Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/17/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
329 PM MST FRI FEB 15 2013
.SHORT TERM...WEAK SHORTWAVE IN NORTHWEST FLOW ALOFT CLIPPING
NORTHEAST PLAINS OF COLORADO AT PRESENT TIME. RADAR INDICATING A
FEW LIGHT SHOWERS MOVING SOUTHEAST ACROSS WASHINGTON AND ELBERT
COUNTIES ON BACK EDGE OF THE MID LEVEL ASCENT. DOESN`T APPEAR MUCH
IS REACHING THE GROUND BASED ON WEB CAMS AND SURFACE OBS. ENOUGH
MIXING BEHIND SURGE HAS HELPED TO PRODUCE GUSTY WINDS ACROSS MUCH
OF PLAINS WITH SOME GUSTS NEAR 40 MPH FROM DENVER NORTH TOWARD THE
WYOMING BORDER. OVER THE MOUNTAINS...WEB CAMS STILL SHOWING LIGHT
SNOW ALONG THE CONTINENTAL DIVIDE OF SUMMIT AND GRAND COUNTIES...
THOUGH HAS BEEN SHOWING SIGNS OF DECREASING DURING THE PAST
COUPLE OF HOURS. GUSTY WINDS ALSO OCCURRING ACROSS THE MOUNTAINS
AND ALONG THE FOOTHILLS. LATEST RAP SHOWS MOISTURE DEPTH
DECREASING DURING THE EVENING ACROSS THE MOUNTAINS. DESPITE
CONTINUED OROGRAPHICS...SHOULD SEE SNOW DECREASE THROUGH THE
EVENING AND COME TO AN END AROUND MIDNIGHT AS MID LEVEL WARMING
INCREASES AND LAPSE RATES DECREASE. ANY ADDITIONAL ACCUMULATIONS
WILL BE LIGHT. MID LEVEL WARMING TO DEVELOP MOUNTAIN WAVE BY
MIDNIGHT. INCREASING SUBSIDENCE WILL HELP WITH DOWNWARD MOMENTUM
TO INCREASE WINDS ACROSS MOUNTAINS AND ALONG FOOTHILLS. DOES NOT
LOOK LIKE A HIGH WIND SITUATION AS CROSS MOUNTAIN FLOW EXPECTED TO
BE AROUND 40 KTS. MODELS SHOW SOME HINTS OF THE WAVE WEAKENING
AFTER MIDNIGHT...WITH PERHAPS A DECREASE IN THE SPEEDS. ACROSS THE
PLAINS...WINDS TO GRADUALLY DECREASE DURING THE EVENING AS SURFACE
GRADIENT WEAKENS...THOUGH MAY REMAIN GUSTY NEAR THE BASE OF THE
FOOTHILLS AND FAR EASTERN PLAINS. OVERNIGHT TEMPERATURES TO BE
SLIGHTLY WARMER MOST AREAS DUE TO THE WARM AIR ADVECTION AND WIND.
HOWEVER...LOW LYING AREAS BELOW THE MID LEVEL INVERSION TO BE MUCH
COLDER WITH PERHAPS BELOW ZERO READINGS IN THE VALLEYS OF GRAND
AND JACKSON COUNTIES. ON SATURDAY...NORTHWEST FLOW ALOFT TO
CONTINUE AS UPPER RIDGE BUILDS ACROSS THE GREAT BASIN...THOUGH
GRADIENT WILL BE WEAKER. SO WINDS TO BE LIGHTER...THOUGH WILL
STILL BE A BIT GUSTY ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS.
SOME MIXING POSSIBLE OVER THE PLAINS COULD CREATE SOME GUSTY
NORTHWEST WINDS DURING THE AFTERNOON. HIGHS TO WARM INTO THE 50S
ACROSS THE PLAINS.
.LONG TERM...ON SATURDAY NIGHT...AN UPPER LEVEL TROUGH WILL BE OVER
THE NORTHERN ROCKIES WHILE A WEAK RIDGE MOVES ACROSS COLORADO. THIS
IS EXPECTED TO BRING DRY CONDITIONS SATURDAY NIGHT AND FOR MOST OF
SUNDAY. COULD SEE A FEW LIGHT SNOW SHOWERS LATE SUNDAY AFTERNOON
OVER THE MOUNTAINS OF NORTH CENTRAL COLORADO AS THE UPPER LEVEL
TROUGH OVER THE NORTHERN ROCKIES SHIFTS EAST-SOUTHEAST. A SURFACE
LOW WILL FORM OVER SOUTHEAST COLORADO SUNDAY IN ADVANCE OF THE
TROUGH. THIS WILL CAUSE WINDS TO TURN NORTHERLY OVER NORTHEAST
COLORADO SUNDAY AFTERNOON. EXPECT THIS TO START PULLING IN COOLER
AIR SO DROPPED HIGHS FOR SUNDAY A FEW DEGREES. HOWEVER...IT WILL
STILL BE MILD WITH HIGHS IN THE 50S.
THE BASE OF THE TROUGH WILL MOVE ACROSS WYOMING AND NORTHERN
COLORADO SUNDAY NIGHT AND EARLY MONDAY. THIS WILL LIKELY BRING A
SHOT OF LIGHT SNOW TO THE MOUNTAINS. FOR THE FRONT RANGE...NOT A
FAVORABLE SET UP BUT WINDS MAY TURN UPSLOPE FOR LONG ENOUGH TO
PRODUCE LIGHT SNOW ALONG THE FRONT RANGE. THE PLAINS MAY SEE A LIGHT
DUSTING AT BEST. SNOW MAY LINGER INTO MONDAY MORNING OVER THE
MOUNTAINS AND PALMER DIVIDE BEFORE DRIER MOVES IN FOR MONDAY
AFTERNOON.
A WEAK RIDGE WILL KEEP DRY CONDITIONS OVER COLORADO MONDAY NIGHT AND
TUESDAY. HIGHS WILL BE NEAR NORMAL TUESDAY WITH READINGS IN THE 40S.
A DEEP TROUGH WILL MOVE ONTO THE CALIFORNIA COAST TUESDAY. GENERAL
PATTERN HAS BEEN CONSISTENT FOR THE PAST FEW DAYS WITH THIS DEEP
TROUGH CLOSING OFF AND MOVING ACROSS THE GREAT BASIN AND THEN THE
ROCKIES BY MID TO LATE WEEK. DETAILS ON TRACK DEVELOPMENT STILL
NEEDS TO BE WORKED OUT. TEMPERATURES WILL BE COOL WITH MOST PLACES
SEEING PRECIPITATION SOMETIME LATE WEDNESDAY THROUGH THURSDAY. MANY
OF THE MODELS ARE SHOWING A CLOSED LOW LIFTING NORTHEAST ACROSS UTAH
ON WEDNESDAY AND THEN REFORMING THE MAIN LOW OVER SOUTHEAST COLORADO
BY THURSDAY MORNING. THIS WOULD WORK AGAINST HEAVY SNOW FOR THE
FRONT RANGE. ONCE THE LOW REFORMS OVER SOUTHEAST COLORADO...IT WILL
THEN LIFT NORTHEAST ACROSS THE CENTRAL PLAINS WHERE IT WILL LIKELY
PRODUCE BLIZZARD CONDITIONS THURSDAY AND THURSDAY NIGHT. WILL HAVE
THE HIGHEST POPS OVER THE COLORADO EASTERN PLAINS BECAUSE OF THIS.
EXPECT COOL CONDITIONS TO PREVAIL FRIDAY BECAUSE OF A LONG WAVE
TROUGH STILL OVER THE WESTERN U.S. A WEAKER TROUGH WILL BE OVER THE
GREAT BASIN FRIDAY AND WILL HAVE LOW POPS IN THE MOUNTAINS FOR THIS
SYSTEM.
&&
.AVIATION...GUSTY NORTHERLY WINDS AT DEN BEGINNING TO SHOW SOME
SIGNS OF DECREASING AND SHIFTING TO THE NORTHEAST. GRADIENT WEAKER
AND BJC AND APA. CEILINGS HAVE INCREASED TO ABOVE 7000 FEET AGL
WITH VFR PREVAILING. WINDS TO CONTINUE TO WEAKEN ACROSS THE AREA
AIRPORTS...BECOMING SOUTHEAST AROUND 03Z. SOUTHWEST DRAINAGE WINDS
TO THEN DEVELOP BY 06Z...THOUGH MAY BE MORE WESTERLY AT BJC.
POSSIBLE MOUNTAIN WAVE OVER FRONT RANGE OVERNIGHT WITH POTENTIAL
GUSTS TO 40 KTS AT BJC. WINDS TO SHIFT TO THE NORTHWEST AT 15Z
SATURDAY. SOME GUSTS TO 20 KTS POSSIBLE AT DEN. VFR TO CONTINUE
WITH UNLIMTED CEILINGS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....MEIER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1022 AM MST FRI FEB 15 2013
.UPDATE...
&&
.AVIATION...WILL NEED TO DELAY THE ONSET OF THE NORTHERLY WINDS
TIL 20Z BASED ON CURRENT CONDITIONS AND LATEST RAP AND HRRR
SOLUTIONS. ALL ELSE SEEM IN ORDER.
&&
.PREV DISCUSSION... /ISSUED 1017 AM MST FRI FEB 15 2013/
UPDATE...
SHORT TERM...CURRENT FORECASTS LOOK ON TRACK. PASSING SHORTWAVE
ACROSS PLAINS IN NORTHWEST FLOW PRODUCING LIGHT SNOW SHOWERS NORTH
AND EAST OF DENVER AREA. ACROSS MOUNTAINS...GOOD OROGRAPHICS
KEEPING LIGHT SNOW GOING DESPITE STRONG SUBSIDENCE AND STABILITY.
LATEST RAP CROSS SECTIONS SHOWING ANOTHER WEAK MID LEVEL SHORTWAVE
CLIPPING THE NORTHEAST CORNER DURING THE AFTERNOON WITH SOME MID
LEVEL QG ASCENT. NEARBY JET WILL HELP PRODUCE SOME SNOW SHOWERS
ACROSS THE PLAINS INTO THE EARLY EVENING. NOT EXPECTING MUCH IN
THE WAY OF ACCUMULATION WITH THE SHOWERS...THOUGH THE LIFT AND
SLIGHT COOLING WITH A FRONTAL SURGE COULD PRODUCE SOME BRIEF
ACCUMULATION WITH THE STRONGER SHOWERS. STILL EXPECTING ANY
ACCUMULATION TO BE LESS THAN AN INCH...EVEN WITH THE STRONGER
ACTIVITY. MOUNTAIN ACTIVITY TO GRADUALLY DECREASE BY THE EVENING
AS MOISTURE DEPTH DECREASES. FOR TONIGHT...DESPITE THE WARMING
ALOFT AND POTENTIAL FOR BRIEF MOUNTAIN WAVE...THREAT FOR HIGH
WINDS APPEARS LOW WITH THE GUSTY WINDS CONFINED TO THE HIGHER
RIDGES.
AVIATION...CURRENT TAF TRENDS ON TRACK WITH VFR CONDITIONS
PREVAILING. WEAK NORTHERLY SURGE EXPECTED TO PASS ACROSS THE AREA
AIRPORTS WITH WINDS BECOMING NORTHERLY AROUND 18Z. A FEW PASSING
SNOW SHOWERS STILL EXPECTED ACROSS THE PLAINS THROUGH THE
AFTERNOON...MAINLY NORTH AND EAST OF THE DENVER AREA. A SMALL
CHANCE OF SHOWERS MOVING ACROSS THE AREA AIRPORTS WITH POSSIBLE
MVFR CONDITIONS. SNOW FALL THAT DOES OCCUR WILL BE LIGHT WITH LESS
THAN AN INCH OF SNOW ACCUMULATION. MOUNTAIN WAVE APPEARS LESS
LIKELY FOR THE FRONT RANGE TONIGHT...BUT WILL KEEP THE POTENTIAL
FOR SOME GUSTS TO 40 KTS AT BJC.
PREV DISCUSSION... /ISSUED 418 AM MST FRI FEB 15 2013/
SHORT TERM...A SERIES OF RIPPLES IN NORTHWEST FLOW ALOFT WILL
CONTINUE TODAY. VERY LIGHT SNOW SHOWERS CONTINUE ON THE
PLAINS...WITH NORTHWEST WINDS ALOFT SHIELDING AREAS CLOSE TO THE
FOOTHILLS. SURFACE OBSERVATIONS HAVE SHOWN DECENT SHOWER COVERAGE
BACK THROUGH THE LAST WAVE IN WYOMING DESPITE ONLY VERY WEAK RADAR
ECHOES. MOISTURE...LIFT...AND INSTABILITY ALL MORE LIMITED TODAY
ALTHOUGH THERE WILL BE SOME COOLING AGAIN WITH A FRONTAL SURGE
AROUND MIDDAY. THIS COULD ALLOW SHOWERS TO BE A BIT STRONGER AND
COULD ALLOW FOR THE SHOWERS TO BACK INTO DENVER OR BRIEFLY
OVERPOWER THE DOWNSLOPING...BUT STILL EXPECT ANYTHING TO BE QUITE
LIGHT. MADE ONLY A SLIGHT UPWARD NUDGE TO POPS AS MUCH OF THE SNOW
WILL BE TRACE AMOUNTS.
STRONG WARMING ALOFT SHOULD BRING A QUICK END TO THE SHOWERS IN
THE LATE AFTERNOON OR EARLY EVENING. SOME CLOUD COVER STILL
EXPECTED...ENHANCED BY A PERIOD OF MOUNTAIN WAVE ACTIVITY AS THE
WARMING ALOFT KICKS IN THIS EVENING. COULD EVEN BE A BRIEF HIGH
WIND THREAT...BUT CONDITIONS WILL ONLY BE FAVORABLE FOR A FEW
HOURS AND LOW LEVEL STABILITY WOULD LIKELY KEEP THE STRONGEST
WINDS FROM REACHING THE PLAINS. BEST GUESS IS A BRIEF MARGINAL
EVENT FOR THE BOULDER/NORTHERN JEFFCO FOOTHILLS AND NOT A LOT
ELSEWHERE...THEN THE AMPLIFICATION SHOULD DIMINISH OVERNIGHT BUT
MORE WIDESPREAD WINDY CONDITIONS AT LEAST ABOVE 7500 FEET.
DEVELOPING WINDS AND SOME CLOUD COVER WILL LIKELY BRING SOME
WARMING LATER TONIGHT IN MANY AREAS...AND MILDER TEMPERATURES
EVERYWHERE WITH THE POSSIBLE EXCEPTION OF JACKSON/GRAND COUNTY
VALLEYS WHICH WILL LIKELY BE BELOW ZERO UNDER MOSTLY CLEAR SKIES.
LONG TERM...FAIRLY WEAK NORTHWESTERLY FLOW ALOFT IS PROGGED ON
SATURDAY WITH AN UPPER RIDGE TO MOVE ACROSS COLORADO THROUGH THE DAY
INTO SATURDAY NIGHT. THE FLOW ALOFT BECOME WESTERLY LATE SATURDAY
NIGHT...THEN WEST-SOUTHWESTERLY ON SUNDAY. THE NEXT UPPER TROUGH
IS PROGGED TO MOVE ACROSS COLORADO SUNDAY NIGHT INTO MONDAY
MORNING. THE SYNOPTIC SCALE ENERGY FOR THE CWA IS BENIGN SATURDAY
AND SATURDAY NIGHT. ON SUNDAY AND SUNDAY EVENING...UPWARD ENERGY
IS EXPECTED. DOWNWARD MOTION IS PROGGED FOR THE FORECAST AREA BY
12Z MONDAY MORNING. THE BOUNDARY LAYER WINDS ARE PROGGED TO BE
DOWNSLOPING IN NATURE SATURDAY INTO SATURDAY NIGHT. SUNDAY`S
SHOULD BE NORMAL PATTERNS EARLY...THEN A COLD FRONT WITH UPSLOPE IS
PROGGED IN DURING THE AFTERNOON. THE NORTHERLY FLOW BECOMES MORE
NORTHWESTERLY BY LATER SUNDAY NIGHT. FOR MOISTURE...SATURDAY AND
SATURDAY NIGHT ARE DRY...THEN MOISTURE INCREASES AND DEEPENS
SOMEWHAT THROUGH THE DAY SUNDAY. MOISTURE LOOKS FAIRLY DEEP
SUNDAY NIGHT AND THE NAM ACTUALLY HAS MORE THAN THE GFS. THE
ECMWF HAS THE LEAST MOISTURE. THE QPF FIELDS HAVE NO MEASURABLE
PRECIPITATION SATURDAY THROUGH SUNDAY. THEN BY SUNDAY NIGHT...
THERE IS A TAD OF MEASURABLE SNOWFALL OVER THE MOUNTAINS...
FOOTHILLS AND IMMEDIATE PLAINS. WILL GO WITH "CHANCE"S OVER THE
FOOTHILLS AND MOUNTAINS SUNDAY NIGHT...AND "SLIGHT CHANCE"S OVER
THE WESTERN PLAINS AND PALMER RIDGE. NOT TOO EXCITING. FOR
TEMPERATURES...SATURDAY`S HIGHS STILL LOOK TO BE 7-11 C WARMER THAN
TODAY`S. SUNDAY`S ARE CLOSE TO SATURDAY`S. FOR THE LATER DAYS...
MONDAY THROUGH THURSDAY...MODELS GET THE WEAK UPPER TROUGH
THROUGH THE CWA EARLY MONDAY MORNING...WITH STRONG NORTHWESTERLY
FLOW ALOFT MONDAY. THE FLOW ALOFT DECREASES AND BECOMES ZONAL
LATER MONDAY INTO MID DAY TUESDAY AS AN UPPER RIDGE MOVES ACROSS
COLORADO. SOUTHWESTERLY FLOW ALOFT INCREASES OVER THE CWA TUESDAY
AND WEDNESDAY. BY LATE WEDNESDAY AND WEDNESDAY NIGHT...MODELS SHOW
A PRETTY DECENT UPPER TROUGH/CLOSED LOW TO GET INTO COLORADO. THE
ECMWF SOLUTION LOOKS MORE FAVORABLE FOR A DECENT SNOWFALL EAST OF
THE DIVIDE WITH THE CIRCULATION CENTER TO MOVE EASTWARD ACROSS
NORTHERN NEW MEXICO WEDNESDAY NIGHT INTO THURSDAY MORNING. THE GFS
ISN`T BAD...SHOWING THE CIRCULATION A TAD FURTHER NORTH...HOWEVER
IT ALSO HAS ANOTHER CIRCULATION WELL NORTH OF COLORADO INSIDE THE
LARGE UPPER TROUGH. IT`S STILL SO EARLY...ESPECIALLY CONSIDERING
THE MODEL PERFORMANCE THESE DAYS. MONDAY INTO EARLY WEDNESDAY LOOK
DRY WITH NEAR NORMALS TEMPERATURES. WILL GO WITH OR KEEP IN SNOW
CHANCES...OR SLIGHT CHANCES...WEDNESDAY AFTERNOON INTO THURSDAY
AFTERNOON.
AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT. LIGHT
SNOW SHOWERS WILL MAINLY BE EAST OF DENVER...BUT THERE IS A CHANCE
THAT THEY WILL BACK OVER THE CITY AND BRING MVFR CONDITIONS AND
LESS THAN AN INCH OF SNOW. THE HIGHEST THREAT FOR THIS IS IN THE
EARLY AFTERNOON. SHOWERS AND THE THREAT OF LOWER CEILINGS WILL BE
ENDING IN THE LATE AFTERNOON. MOUNTAIN WAVE LIKELY OVER THE FRONT
RANGE TONIGHT...STRONG WINDS MAINLY EXPECTED OVER THE FOOTHILLS
BUT POSSIBLE LLWS OR OCCASIONAL GUSTS TO 40 KNOTS AT KBJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1017 AM MST FRI FEB 15 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS LOOK ON TRACK. PASSING SHORTWAVE
ACROSS PLAINS IN NORTHWEST FLOW PRODUCING LIGHT SNOW SHOWERS NORTH
AND EAST OF DENVER AREA. ACROSS MOUNTAINS...GOOD OROGRAPHICS
KEEPING LIGHT SNOW GOING DESPITE STRONG SUBSIDENCE AND STABILITY.
LATEST RAP CROSS SECTIONS SHOWING ANOTHER WEAK MID LEVEL SHORTWAVE
CLIPPING THE NORTHEAST CORNER DURING THE AFTERNOON WITH SOME MID
LEVEL QG ASCENT. NEARBY JET WILL HELP PRODUCE SOME SNOW SHOWERS
ACROSS THE PLAINS INTO THE EARLY EVENING. NOT EXPECTING MUCH IN
THE WAY OF ACCUMULATION WITH THE SHOWERS...THOUGH THE LIFT AND
SLIGHT COOLING WITH A FRONTAL SURGE COULD PRODUCE SOME BRIEF
ACCUMULATION WITH THE STRONGER SHOWERS. STILL EXPECTING ANY
ACCUMULATION TO BE LESS THAN AN INCH...EVEN WITH THE STRONGER
ACTIVITY. MOUNTAIN ACTIVITY TO GRADUALLY DECREASE BY THE EVENING
AS MOISTURE DEPTH DECREASES. FOR TONIGHT...DESPITE THE WARMING
ALOFT AND POTENTIAL FOR BRIEF MOUNTAIN WAVE...THREAT FOR HIGH
WINDS APPEARS LOW WITH THE GUSTY WINDS CONFINED TO THE HIGHER
RIDGES.
.AVIATION...CURRENT TAF TRENDS ON TRACK WITH VFR CONDITIONS
PREVAILING. WEAK NORTHERLY SURGE EXPECTED TO PASS ACROSS THE AREA
AIRPORTS WITH WINDS BECOMING NORTHERLY AROUND 18Z. A FEW PASSING
SNOW SHOWERS STILL EXPECTED ACROSS THE PLAINS THROUGH THE
AFTERNOON...MAINLY NORTH AND EAST OF THE DENVER AREA. A SMALL
CHANCE OF SHOWERS MOVING ACROSS THE AREA AIRPORTS WITH POSSIBLE
MVFR CONDITIONS. SNOW FALL THAT DOES OCCUR WILL BE LIGHT WITH LESS
THAN AN INCH OF SNOW ACCUMULATION. MOUNTAIN WAVE APPEARS LESS
LIKELY FOR THE FRONT RANGE TONIGHT...BUT WILL KEEP THE POTENTIAL
FOR SOME GUSTS TO 40 KTS AT BJC.
&&
.PREV DISCUSSION... /ISSUED 418 AM MST FRI FEB 15 2013/
SHORT TERM...A SERIES OF RIPPLES IN NORTHWEST FLOW ALOFT WILL
CONTINUE TODAY. VERY LIGHT SNOW SHOWERS CONTINUE ON THE
PLAINS...WITH NORTHWEST WINDS ALOFT SHIELDING AREAS CLOSE TO THE
FOOTHILLS. SURFACE OBSERVATIONS HAVE SHOWN DECENT SHOWER COVERAGE
BACK THROUGH THE LAST WAVE IN WYOMING DESPITE ONLY VERY WEAK RADAR
ECHOES. MOISTURE...LIFT...AND INSTABILITY ALL MORE LIMITED TODAY
ALTHOUGH THERE WILL BE SOME COOLING AGAIN WITH A FRONTAL SURGE
AROUND MIDDAY. THIS COULD ALLOW SHOWERS TO BE A BIT STRONGER AND
COULD ALLOW FOR THE SHOWERS TO BACK INTO DENVER OR BRIEFLY
OVERPOWER THE DOWNSLOPING...BUT STILL EXPECT ANYTHING TO BE QUITE
LIGHT. MADE ONLY A SLIGHT UPWARD NUDGE TO POPS AS MUCH OF THE SNOW
WILL BE TRACE AMOUNTS.
STRONG WARMING ALOFT SHOULD BRING A QUICK END TO THE SHOWERS IN
THE LATE AFTERNOON OR EARLY EVENING. SOME CLOUD COVER STILL
EXPECTED...ENHANCED BY A PERIOD OF MOUNTAIN WAVE ACTIVITY AS THE
WARMING ALOFT KICKS IN THIS EVENING. COULD EVEN BE A BRIEF HIGH
WIND THREAT...BUT CONDITIONS WILL ONLY BE FAVORABLE FOR A FEW
HOURS AND LOW LEVEL STABILITY WOULD LIKELY KEEP THE STRONGEST
WINDS FROM REACHING THE PLAINS. BEST GUESS IS A BRIEF MARGINAL
EVENT FOR THE BOULDER/NORTHERN JEFFCO FOOTHILLS AND NOT A LOT
ELSEWHERE...THEN THE AMPLIFICATION SHOULD DIMINISH OVERNIGHT BUT
MORE WIDESPREAD WINDY CONDITIONS AT LEAST ABOVE 7500 FEET.
DEVELOPING WINDS AND SOME CLOUD COVER WILL LIKELY BRING SOME
WARMING LATER TONIGHT IN MANY AREAS...AND MILDER TEMPERATURES
EVERYWHERE WITH THE POSSIBLE EXCEPTION OF JACKSON/GRAND COUNTY
VALLEYS WHICH WILL LIKELY BE BELOW ZERO UNDER MOSTLY CLEAR SKIES.
LONG TERM...FAIRLY WEAK NORTHWESTERLY FLOW ALOFT IS PROGGED ON
SATURDAY WITH AN UPPER RIDGE TO MOVE ACROSS COLORADO THROUGH THE DAY
INTO SATURDAY NIGHT. THE FLOW ALOFT BECOME WESTERLY LATE SATURDAY
NIGHT...THEN WEST-SOUTHWESTERLY ON SUNDAY. THE NEXT UPPER TROUGH
IS PROGGED TO MOVE ACROSS COLORADO SUNDAY NIGHT INTO MONDAY
MORNING. THE SYNOPTIC SCALE ENERGY FOR THE CWA IS BENIGN SATURDAY
AND SATURDAY NIGHT. ON SUNDAY AND SUNDAY EVENING...UPWARD ENERGY
IS EXPECTED. DOWNWARD MOTION IS PROGGED FOR THE FORECAST AREA BY
12Z MONDAY MORNING. THE BOUNDARY LAYER WINDS ARE PROGGED TO BE
DOWNSLOPING IN NATURE SATURDAY INTO SATURDAY NIGHT. SUNDAY`S
SHOULD BE NORMAL PATTERNS EARLY...THEN A COLD FRONT WITH UPSLOPE IS
PROGGED IN DURING THE AFTERNOON. THE NORTHERLY FLOW BECOMES MORE
NORTHWESTERLY BY LATER SUNDAY NIGHT. FOR MOISTURE...SATURDAY AND
SATURDAY NIGHT ARE DRY...THEN MOISTURE INCREASES AND DEEPENS
SOMEWHAT THROUGH THE DAY SUNDAY. MOISTURE LOOKS FAIRLY DEEP
SUNDAY NIGHT AND THE NAM ACTUALLY HAS MORE THAN THE GFS. THE
ECMWF HAS THE LEAST MOISTURE. THE QPF FIELDS HAVE NO MEASURABLE
PRECIPITATION SATURDAY THROUGH SUNDAY. THEN BY SUNDAY NIGHT...
THERE IS A TAD OF MEASURABLE SNOWFALL OVER THE MOUNTAINS...
FOOTHILLS AND IMMEDIATE PLAINS. WILL GO WITH "CHANCE"S OVER THE
FOOTHILLS AND MOUNTAINS SUNDAY NIGHT...AND "SLIGHT CHANCE"S OVER
THE WESTERN PLAINS AND PALMER RIDGE. NOT TOO EXCITING. FOR
TEMPERATURES...SATURDAY`S HIGHS STILL LOOK TO BE 7-11 C WARMER THAN
TODAY`S. SUNDAY`S ARE CLOSE TO SATURDAY`S. FOR THE LATER DAYS...
MONDAY THROUGH THURSDAY...MODELS GET THE WEAK UPPER TROUGH
THROUGH THE CWA EARLY MONDAY MORNING...WITH STRONG NORTHWESTERLY
FLOW ALOFT MONDAY. THE FLOW ALOFT DECREASES AND BECOMES ZONAL
LATER MONDAY INTO MID DAY TUESDAY AS AN UPPER RIDGE MOVES ACROSS
COLORADO. SOUTHWESTERLY FLOW ALOFT INCREASES OVER THE CWA TUESDAY
AND WEDNESDAY. BY LATE WEDNESDAY AND WEDNESDAY NIGHT...MODELS SHOW
A PRETTY DECENT UPPER TROUGH/CLOSED LOW TO GET INTO COLORADO. THE
ECMWF SOLUTION LOOKS MORE FAVORABLE FOR A DECENT SNOWFALL EAST OF
THE DIVIDE WITH THE CIRCULATION CENTER TO MOVE EASTWARD ACROSS
NORTHERN NEW MEXICO WEDNESDAY NIGHT INTO THURSDAY MORNING. THE GFS
ISN`T BAD...SHOWING THE CIRCULATION A TAD FURTHER NORTH...HOWEVER
IT ALSO HAS ANOTHER CIRCULATION WELL NORTH OF COLORADO INSIDE THE
LARGE UPPER TROUGH. IT`S STILL SO EARLY...ESPECIALLY CONSIDERING
THE MODEL PERFORMANCE THESE DAYS. MONDAY INTO EARLY WEDNESDAY LOOK
DRY WITH NEAR NORMALS TEMPERATURES. WILL GO WITH OR KEEP IN SNOW
CHANCES...OR SLIGHT CHANCES...WEDNESDAY AFTERNOON INTO THURSDAY
AFTERNOON.
AVIATION...VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT. LIGHT
SNOW SHOWERS WILL MAINLY BE EAST OF DENVER...BUT THERE IS A CHANCE
THAT THEY WILL BACK OVER THE CITY AND BRING MVFR CONDITIONS AND
LESS THAN AN INCH OF SNOW. THE HIGHEST THREAT FOR THIS IS IN THE
EARLY AFTERNOON. SHOWERS AND THE THREAT OF LOWER CEILINGS WILL BE
ENDING IN THE LATE AFTERNOON. MOUNTAIN WAVE LIKELY OVER THE FRONT
RANGE TONIGHT...STRONG WINDS MAINLY EXPECTED OVER THE FOOTHILLS
BUT POSSIBLE LLWS OR OCCASIONAL GUSTS TO 40 KNOTS AT KBJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1032 PM MST THU FEB 14 2013
.UPDATE...
ISSUED AT 546 PM MST THU FEB 14 2013
ADJUSTED POPS TO REDUCE COVERAGE OF SNOW ACROSS THE SOUTHEAST MTS/PLAINS.
GREATEST COVERAGE FOR THE NEXT COUPLE HOURS WILL BE ACROSS THE
LOWER EASTERN SLOPES OF THE SANGRES/WETS AND SRN I-25 CORRIDOR.
TREND WILL BE FOR WINDS TO SHIFT OUT OF THE SOUTHEAST WITH SOME
ISOLATED TO SCATTERED SNOW SHOWERS POSSIBLE ACROSS PORTIONS OF
SOUTHERN EL PASO COUNTY. DOESN`T APPEAR SNOWFALL WILL AMOUNT TO
MUCH WITH MOST AMOUNTS STAYING WELL UNDER 1 INCH. LATEST HIGH RES
MODELS REALLY DIMINISH PCPN QUICKLY TOWARDS 06Z. CURRENT GRIDS
ALREADY HAD THIS TREND WELL DEPICTED SO MAIN CHANGE WAS TO THE
FIRST 3 HOURS. -KT
&&
.SHORT TERM...(TONIGHT AND TOMORROW)
ISSUED AT 308 PM MST THU FEB 14 2013
A FAST MOVING COLD FRONT HAS MOVED SOUTH OF HIGHWAY 50. THE FRONT
SHOULD CLEAR THE CO/NM BORDER BY 22Z. THE HRRR AND RAP PROG ANY
LINGERING SNOW SHOWERS TO END BY MIDNIGHT ACROSS THE AREA.
HOWEVER...THE NAM12 AND GFS ARE HOLDING ON TO SNOW SHOWERS
THROUGH 12Z ACROSS THE SOUTHERN I-25 CORRIDOR. DECIDED TO LEAVE
SOME 15 TO 35 POPS SOUTH AND WEST OF TAD IN THE GRIDS. DUE TO TO
THE FAST MOVEMENT OF THE FRONT/PRECIP...LITTLE TO NO ACCUMULATIONS
ARE EXPECTED UNDER ANY OF THE SNOW SHOWERS EAST OF THE CONTINENTAL
DIVIDE. GUSTY NORTHEAST WINDS WILL BEGIN TO RELAX AFTER 02Z. WEST
OF THE I-25 CORRIDOR...LIGHT SNOW SHOWERS WILL CONTINUE IN AND
AROUND THE LEADVILLE AREA OVERNIGHT INTO TOMORROW MORNING. THE
SAN LUIS VALLEY WILL BE MOSTLY CLEAR...COLD...AND DRY OVERNIGHT
FRIDAY...MODELS CONTINUE TO SHOW LIGHT SNOW SHOWERS IN THE LEADVILLE
AREA THROUGH FRIDAY AFTERNOON AND HAVE KEPT POPS IN PLACE AS PREVIOUSLY
FORECASTED. 700MB TEMPERATURES WILL FALLING TO -11 TO -13.5C WILL
KEEP HIGH TEMPERATURES 3-5 DEGREES COOLER ACROSS MOST LOCATIONS
FRIDAY AFTERNOON. A FEW LINGERING CLOUDS ACROSS THE AREA WILL ALSO
HELP TO CAP HIGH TEMPERATURES TOMORROW AFTERNOON. -PJC
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 308 PM MST THU FEB 14 2013
(FRIDAY NIGHT-THURSDAY)
FRIDAY NIGHT-SUNDAY...STRONG NORTH TO NORTHWEST FLOW ALOFT ACROSS
THE REGION FRIDAY NIGHT MODERATES AND BECOMES MORE WESTERLY THROUGH
THE DAY SUNDAY AS UPPER LEVEL RIDGING BUILDING ACROSS THE GREAT
BASIN FLATTENS ACROSS THE STATE AHEAD OF MORE SHORT WAVE ENERGY
MOVING ONSHORE ACROSS THE PAC NORTHWEST COAST. DRY WEATHER WITH WELL
ABOVE SEASONAL TEMPERATURES EXPECTED THROUGH THE FIRST PART OF THE
HOLIDAY WEEKEND...WITH BREEZY WEST WINDS ACROSS THE HIGHER TERRAIN
AND IMMEDIATE ADJACENT PLAINS SATURDAY AND SATURDAY NIGHT. SHOULD
SEE INCREASING HIGH CLOUDS FROM WEST TO EAST THROUGH THE DAY SUNDAY
AS THE SYSTEM CONTINUES TO MOVE ACROSS THE GREAT BASIN.
SUNDAY NIGHT-MONDAY NIGHT...STILL SOME MODEL DIFFERENCES ON AMPLITUDE
OF GREAT BASIN SYSTEM MOVING ACROSS THE ROCKIES WITH THE 12Z GFS
STILL DIGGING FURTHER SOUTH THAN THE ECMWF...HOWEVER THE GFS HAS
STARTED TO TREND FURTHER NORTH AND IS WEAKER WITH THE SYSTEM THAN
PREVIOUS RUNS. WITH THAT SAID...SHOULD STILL SEE A HEALTHY COLD
FRONT WITH A 10-20 DEGREE DROP IN TEMPERATURES FROM SUNDAY...MOST
NOTICEABLE ACROSS EASTERN COLORADO. HAVE ALSO KEPT ISOLATED TO
SCATTERED POPS INTACT ACROSS THE HIGHER TERRAIN AND IMMEDIATE
ADJACENT PLAINS...WITH NOT MUCH PRECIPITATION EXPECTED...ESPECIALLY
IF THE SYSTEM CONTINUES TO TREND FURTHER NORTH.
TUESDAY-THURSDAY...WARMER WESTERLY FLOW PROGGED ACROSS THE AREA
TUESDAY WITH INCREASING SOUTHWEST FLOW TUESDAY NIGHT AND WEDNESDAY
AHEAD OF A STRONGER SYSTEM MOVING INTO THE GREAT BASIN. SOME
DIFFERENCES IN MOVEMENT OF THIS SYSTEM WITH THE GFS LIFTING IT
ACROSS SOUTH CENTRAL COLORADO WEDNESDAY NIGHT AND INTO THE NORTHWEST
KANSAS ON THURSDAY. THE LATEST EC IS A TAD FURTHER SOUTH WITH THE
SYSTEM ACROSS SOUTHWEST KANSAS ON THURSDAY...WHICH PRODUCES BETTER
CHANCES OF SNOW AND BLOWING SNOW ACROSS THE SOUTHEAST PLAINS NORTH
OF HIGHWAY 50...ESPECIALLY AREAS ALONG THE PALMER DVD. AT ANY
RATE...MODEL CONSENSUS IS FAIRLY CONSERVATIVE THIS FAR OUT AND
HAVE INCREASED POPS TO CHANCES ALONG THE CONTDVD FOR THE WEDNESDAY
THROUGH EARLY THURSDAY PERIODS. HAVE ALSO INCREASED POPS TO SLIGHT
CHANCES ACROSS PORTIONS OF THE PLAINS. THIS SYSTEM WILL LIKELY
PRODUCE SIGNIFICANT WEATHER SOMEWHERE ACROSS THE REGION...THOUGH
TIME WILL TELL AS TO EXACTLY WHERE. -MW
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1027 PM MST THU FEB 14 2013
VFR CONDITIONS TO CONTINUE FOR KPUB AND KALS OVER THE NEXT 24 HRS.
FOR KCOS AND MUCH OF EL PASO COUNTY AND THE PALMER DVD...VERY
ISOLATED SNOW AND MVFR CLOUD DECK IS EXPECTED TO PERSIST FOR MUCH
OF THE NIGHT THROUGH 14Z TOMORROW MORNING BEFORE BREAKING UP.
BRISK N-NW SFC WINDS WILL REDEVELOP BETWEEN 16Z AND 18Z MOST
LOCATIONS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TORGERSON
SHORT TERM...PJC
LONG TERM...MW
AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
346 PM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT MOVES ACROSS THE REGION TONIGHT AND STALLS TO OUR EAST
ON SATURDAY. A NOR`EASTER WILL DEVELOP SATURDAY NIGHT WELL
SOUTHEAST OF MONTAUK AND TRACK TOWARDS THE CANADIAN MARITIMES WITH
THE HEAVIEST PRECIPITATION REMAINING JUST EAST OF THE AREA. COLD
CANADIAN HIGH PRESSURE GRADUALLY BUILDS IN FOR SUNDAY INTO
MONDAY. A COLD FRONT TRACKS ACROSS THE REGION LATE TUESDAY
FOLLOWED BY HIGH PRESSURE WEDNESDAY THROUGH THURSDAY. A COMPLEX
FRONTAL SYSTEM WILL APPROACH ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 3 PM...COLD FRONT IS ENTERING ORANGE COUNTY WITH WIND SHIFT
SEEN IN THE METARS. FRONT SLIDES EAST OF US TONIGHT WITH COLD
ADVECTION OVER THE REGION BEGINS. LIGHT PCPN OVER SOUTH CENTRAL PA
EXPANDS RAPIDLY THIS EVENING WITH ONSET AROUND 10 PM OVER NE NJ.
LATEST HRRR THOUGH SUGGEST LIGHT PCPN COULD EVEN MOVE IN A BIT
SOONER.
WE`RE IN AN AREA OF COUPLED JET STREAKS THAT IS PROVIDING ENOUGH
OMEGA FOR THE LIGHT PCPN. QPF IS LESS THAN A QUARTER INCH AND
PERHAPS LESS THAN A TENTH. TEMPS WILL FALL INTO THE 20`S OVER THE
INTERIOR WITH 30`S ALONG THE COAST. THUS...PCPN STARTS AS LIGHT
RAIN ALONG THE COAST AND THEN MIXES WITH WET SNOW...LITTLE OR NO
ACCUMULATION. INLAND...THE PCPN IS MAINLY LIGHT SNOW...THUS 1 TO
LOCALLY 2 INCHES ARE FCST WITH THE MAIN ACCUMULATION OCCURRING ON
THE SNOW PACK DUE TO MARGINAL TEMPS AT THE START OF THE PCPN.
LIGHT PCPN AXIS SLOWLY SHIFTS EAST BY EARLY SATURDAY.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
FOCUS OF ATTENTION IS ON EXPLOSIVE CYCLOGENESIS FORCED BY THE
160+ KT SUB TROPICAL JET LEFT FRONT QUAD ON SATURDAY NIGHT. BASED
ON EXTENSIVE ANALYSIS OF ENSEMBLE SYSTEMS AND COLLABORATION WITHIN
THE NATIONAL WEATHER SERVICE INCLUDING 6 COASTAL WFO`S AND HPC
WWD...CONFIDENCE IS INCREASING ON A NEAR MISS FOR SIGNIFICANT
PCPN SATURDAY NIGHT IN OUR FCST AREA.
HAVE SEEN 12Z ECMWF...15Z SREF...12Z GEFS AND 18Z NAM.
THUS...GOING WITH A CHANCE FOR VERY LIGHT PCPN WHICH WOULD
INCLUDE SPRINKLES AND FLURRIES DURING THE DAY ON SATURDAY WITH
HIGH TEMPS CLOSE TO THE SLIGHT COOLER NAM MOS.
AS THE NOR`EASTER SPINS UP WELL OFF THE MID ATLANTIC COAST
SATURDAY EVENING...POPS INCREASE TO CATEGORICAL EAST WITH LOW
CHANCE WEST. PCPN IS ALL SNOW. HAVE AMOUNTS OF 2-3" FAR EAST AND
AROUND AN INCH FROM NEW HAVEN TO WESTERN SUFFOLK. ELSEWHERE IT`S
JUST A DUSTING. EVEN THESE AMOUNTS COULD BE HIGH.
WILL KEEP THE OUTLOOK FOR THE FAR EASTERN ZONE WITH LOW CHANCE FOR
THE TRACK TO SHIFT BACK SLIGHTLY TO THE WEST.
WINDS REALLY START TO INCREASE AFTER MIDNIGHT.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
MEDIUM RANGE MODEL GUIDANCE IS STILL IN GENERAL AGREEMENT THROUGH
THE END OF THE WEEK. TO START...INTENSE LOW PRESSURE WILL BE MOVING
UP TROUGH THE CANADIAN MARITIMES ON SUNDAY AS ITS PARENT CLOSED
UPPER LOW TRAVERSES THE REGION ON SUNDAY...WITH COLD/BLUSTERY
CONDITIONS. NW FLOW 20-30 MPH WITH GUSTS 35-45 MPH AND TEMPS ONLY
RISING TO THE UPPER 20S AND LOWER 30S WILL RESULT IN WIND CHILLS IN
THE TEENS DURING THE DAY ON SUNDAY. WINDS WILL STILL REMAIN QUITE
BRISK IN TO SUNDAY NIGHT...SO AS TEMPS FALL INTO THE TEENS AND LOWER
20S SUNDAY NIGHT...WIND CHILLS OF OF ZERO TO 10 BELOW ARE LIKELY.
TEMPS AND WIND CHILLS SHOULD RECOVER A LITTLE MON INTO MON NIGHT AS
A NARROW HIGH PRESSURE RIDGE SLIDES ACROSS...WITH HIGHS MAINLY 30-35
AND LOWS MON NIGHT IN THE 20S. AN ACCOMPANYING UPPER RIDGE SHOULD
SLIDE BY TUE MORNING...ALLOWING A FRONTAL SYSTEM TO IMPACT THE AREA
FROM THE WEST TUE INTO TUE NIGHT. IF PCPN ARRIVES EARLY ENOUGH ON
TUE...IT COULD BEGIN AS A BRIEF PD OF SNOW OR A RAIN/SNOW MIX ACROSS
THE INTERIOR...OTHERWISE RAIN SHOULD BE THE PREDOMINANT P-TYPE
DURING THE DAY. AFTER COLD FROPA TUE EVENING...PCPN COULD CHANGE
BACK TO SNOW...ESPECIALLY OVER THE INTERIOR...AS COLDER AIR BEGINS
TO FILTER BACK IN.
THE FLOW ALOFT WILL BEGIN TO TRANSITION TO A MORE BLOCKY REGIME
DURING MID TO LATE NEXT WEEK...WITH TEMPS GENERALLY NEAR AVG.
FIRST...HIGH PRESSURE WILL SLIDE ACROSS WED INTO THU EVENING...THEN
AS ONE LEG OF A DEVELOPING OMEGA OR REX BLOCK BECOMES ESTABLISHED
OVER THE NRN PLAINS LATE IN THE WEEK...A SERIES OF SRN STREAM
DISTURBANCES TRAVELING ALONG ITS SRN PERIPHERY WILL IMPACT THE AREA.
THE FIRST OF THESE SHOULD BRING A LIGHT SNOWFALL EVENT FRI INTO FRI
NIGHT...AS HIGH PRESSURE TO THE NE SUPPLIES COLD SFC AIR AND
WESTERLY FLOW ALOFT PREVENTS MID LEVEL WARMING. THE ECMWF HAS BEEN
CONSISTENTLY PREDICTING A MORE SIGNIFICANT SRN STREAM LOW BEYOND THE
END OF THE FCST PERIOD THAT WILL NEED TO BE WATCHED...SO WINTER
APPEARS FAR FROM BEING OVER.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
A COLD FRONT APPROACHES THIS AFTERNOON AND STALLS BRIEFLY ACROSS
THE AREA AS A WAVE OF LOW PRESSURE PASSES TO THE SOUTH AND EAST
TONIGHT. THE FRONT THEN GRADUALLY WORKS EAST ON SAT.
S/SW WINDS LESS THAN 10 KT THIS AFT MAY BRIEFLY BECOME VARIABLE
OR A LIGHT W/NW THIS EVENING AS THE FRONT MOVES INTO THE AREA.
POTENTIAL FOR POST-FRONTAL PCPN TO DEVELOP LATE TONIGHT WITH MVFR
CONDITIONS. IFR POSSIBLE ACROSS THE LOWER HUDSON VALLEY WHERE PCPN
WILL LIKELY BE ALL SNOW. LIGHT RAIN AT THE ONSET WOULD TRANSITION
OVER TO A WET SNOW TOWARD DAYBREAK. POTENTIAL FOR AROUND AN INCH
AT KHPN AND KSWF...ELSEWHERE LITTLE OR NO SNOW ACCUMULATION
ON RUNWAYS WITH TEMPERATURES JUST ABOVE FREEZING.
GENERALLY VFR ON SAT WITH N WINDS AROUND 10 KT. OCCASIONAL MVFR
CIGS...ESPECIALLY EAST OF THE NYC TERMINALS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: WINDS MAY BECOME LIGHT AND VARIABLE OR LIGHT
W/NW PRIOR TO 22Z.
KJFK FCSTER COMMENTS: WINDS MAY VARY BETWEEN 190-220 THIS AFTERNOON.
KLGA FCSTER COMMENTS: AN OCCASIONAL GUST INTO THE UPPER TEENS
POSSIBLE THIS AFTERNOON.
KTEB FCSTER COMMENTS: WINDS MAY BECOME LIGHT AND VARIABLE OR LIGHT
W/NW PRIOR TO 22Z.
KHPN FCSTER COMMENTS: WINDS MAY BECOME LIGHT AND VARIABLE OR LIGHT
W/NW PRIOR TO 22Z.
KISP FCSTER COMMENTS: WINDS MAY VARY BETWEEN 190-220 THIS AFTERNOON.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.SAT...MVFR POSSIBLE EAST OF NYC TERMINALS IN THE AFT.
.SAT NIGHT-SUN...OFFSHORE LOW DEVELOPMENT WILL NEED TO WATCHED FOR
ADDITIONAL PCPN. STRONG NW FLOW WITH GUSTS OF 35 TO 40 KT POSSIBLE
ON SUN.
.MON...VFR. GUSTY NW FLOW 25 TO 30 KT.
.TUE...PSBL MVFR OR LOWER WITH PCPN. GUSTY SW FLOW.
.WED...VFR. GUSTY W FLOW.
&&
.MARINE...
SUB-SCA CONDITIONS PREVAIL ON ALL WATERS INTO SATURDAY. WINDS VEER
NORTH BY LATE TONIGHT AND INCREASE ON SATURDAY.
GALES WILL LIKELY DEVELOP...ESPECIALLY EAST...LATE SAT
NIGHT AS LOW PRESSURE WELL SOUTHEAST OF MONTAUK RAPIDLY DEEPENS.
THUS GALE WATCH HAS BEEN ISSUED.
GALES LIKELY ON ALL WATERS ON SUNDAY IN THE WAKE OF INTENSE LOW
PRESSURE DEPARTING INTO THE CANADIAN MARITIMES...LASTING INTO SUNDAY
NIGHT-MON ON THE OCEAN AND THE EASTERN SOUND/BAYS.
QUIET CONDS SHOULD RETURN BY LATE DAY MON OR MON EVENING AS WEAK
HIGH PRESSURE SLIDES ACROSS. INCREASING SW FLOW AHEAD OF AN
APPROACHING FRONTAL SYSTEM COULD BRING MARGINAL SCA CONDS TO THE
OCEAN WATERS FROM LATE DAY TUE INTO TUE EVENING...CONTINUING IN W-NW
POST-FRONTAL FLOW ON WED.&&
.HYDROLOGY...
NO HYDROLOGIC IMPACT EXPECTED WITH LIGHT PCPN THOUGH SATURDAY
NIGHT.
QPF WITH FRONTAL SYSTEMS ON TUE /MOSTLY RAIN/ AND AGAIN ON FRI
/SNOW/ SHOULD BE LIGHT AND NOT PRESENT ANY PROBLEMS.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...GOODMAN
AVIATION...DW
MARINE...GOODMAN/TONGUE
HYDROLOGY...TONGUE
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
249 PM EST FRI FEB 15 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 335 AM EST FRI FEB 15 2013
A BROAD UPPER LEVEL LOW WILL SPREAD ACROSS THE GREAT LAKES REGION
THROUGH TOMORROW BRINGING PERIODIC CHANCES FOR LIGHT SNOW SHOWERS.
HIGH PRESSURE WILL THEN BUILD INTO CENTRAL INDIANA BY SUNDAY AS
THE AFOREMENTIONED LOW PUSHES OFF TO THE EAST. AFTER DRY CONDITIONS
ON SUNDAY...ANOTHER UPPER LEVEL LOW WILL BRING PRECIP TO THE
REGION ON MONDAY AND TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1240 PM EST FRI FEB 15 2013
1230 PM UPDATE...CONVECTIVE BANDS OF MODERATE TO HEAVY SNOW IMPACT
THE NORTHERN PORTIONS OF THE FORECAST AREA AT THIS TIME. HAVE BUMPED
UP TO A BRIEF PERIOD OF LIKELY POPS FROM KOKOMO AND TIPTON EAST
THROUGH MUNCIE AND WINCHESTER FOR THE NEXT COUPLE HOURS BASED ON
RADAR TRENDS. BRIEF PERIODS OF HEAVY SNOW DROPPING VISIBILITIES
BELOW 1/2SM IN THE STRONGER SNOW SHOWERS AND CONSIDERING THE
CONVECTIVE NATURE OF THE PRECIP...COULD SEE ICE PELLETS MIX IN
SPORADICALLY. ALSO LIKELY TO SEE QUICK ACCUMS OF A DUSTING TO HALF
INCH WITH THE HEAVIER SNOW SHOWERS...MELTING ONCE SNOW ENDS AS TEMPS
HOVER NEAR FREEZING.
PREVIOUS DISCUSSION FOLLOWS.
SCATTERED LIGHT SNOW AND FLURRIES EXPANDING ACROSS MUCH OF THE
NORTHERN PART OF THE FORECAST AREA SO FAR THIS MORNING AS THE
UPPER WAVE AND ITS ASSOCIATED FORCING MOVE THROUGH. TEMPS ACROSS
THE FORECAST AREA WERE IN THE LOWER AND MID 30S AT 14Z.
FORECAST IN GREAT SHAPE AND HAVE MADE ONLY MINOR ADJUSTMENTS TO
ACCOUNT FOR ONGOING OBS. SCATTERED LIGHT SNOW DEVELOPING A TOUCH
FASTER THAN PREVIOUSLY THOUGHT AS THE STRONGEST FORCING ALOFT
ALREADY INTO THE REGION. EXPECT SNOW SHOWERS TO CONTINUE THROUGH
MID AFTERNOON AS THE UPPER WAVE TRANSITIONS ACROSS THE REGION AND
WILL CONTINUE WITH CHANCE POPS. RAP SOUNDINGS SHOWING SOME WEAK
INSTABILITY DEVELOPING THROUGH EARLY AFTERNOON ALONG WITH
STEEPENING LAPSE RATES UP THROUGH ABOUT 800MB. THIS WILL
CONTRIBUTE TO THE DEVELOPMENT OF A FEW STRONGER CONVECTIVE SNOW
SHOWERS BUT WITH SURFACE TEMPS NEAR TO JUST ABOVE FREEZING AND
LIMITED MOISTURE AVAILABLE...ACCUMULATION POTENTIAL WILL BE
MITIGATED WITH MOST LOCATIONS ONLY SEEING A FEW TENTHS AT BEST.
THE BIGGER IMPACT TO TRAVEL LIKELY TO BE QUICK DROPS IN
VISIBILITIES WITHIN HEAVIER SNOW SHOWERS. MOST PRECIP WILL BE DONE
BY MID AFTERNOON AS THE UPPER WAVE MOVES INTO OHIO. FORECAST HIGHS
IN THE LOW/MID 30S STILL LOOK TO BE ON TRACK.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 335 AM EST FRI FEB 15 2013
DRY CONDITIONS WILL PREVAIL TONIGHT...BUT THE POTENTIAL FOR
PERIODIC SNOW SHOWERS WILL RETURN EARLY SATURDAY MORNING AND
LINGER THROUGH THE DAY AS ANOTHER WEAKER SHORTWAVE PASSES IN THE
UPPER FLOW. WEAK LAKE EFFECT ENHANCEMENT COULD CONTRIBUTE TO SOME
LIGHT SNOW SHOWERS OVER THE NORTHEAST/EASTERN PORTIONS OF CENTRAL
INDIANA THROUGH SATURDAY NIGHT.
HIGH PRESSURE WILL RE-ESTABLISH ITSELF OVER THE AREA ON SATURDAY
NIGHT...RESULTING IN DRY CONDITIONS FOR SUNDAY. MODELS SEEM TO
HAVE A GOOD HANDLE ON THE COOLER AIR ASSOCIATED WITH THE SECOND
WAVE ON SATURDAY...SO STUCK CLOSE TO GUIDANCE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 248 PM EST FRI FEB 15 2013
MODELS ARE IN GOOD AGREEMENT EARLY BUT SOLUTIONS SPREAD BY LATER IN
THE WEEK. THE LONG TERM WILL BEGIN WITH RAIN MONDAY NIGHT AS A COLD
FRONT APPROACHES CENTRAL INDIANA AND MOVES THROUGH THE STATE DURING
THE OVERNIGHT HOURS. RAIN WILL CHANGE OVER TO A MIX BEHIND THE COLD
FRONTAL PASSAGE LATE MONDAY NIGHT. ON TUESDAY MORNING COULD SEE A
BRIEF SNOW SHOWER BEFORE THE SYSTEM MOVES OUT AND COULD HOLD ON TO
FLURRIES IN THE NORTHEAST THROUGH THE DAY. CANADIAN HIGH PRESSURE
WILL MOVE INTO THE AREA AFTER THAT BRINGING EVEN COLDER TEMPERATURES
AND DRY WEATHER WITH IT. BY THURSDAY THE NEXT SYSTEM WILL SWING OUT
OF THE PLAINS AND BRING SOME ISENTROPIC LIFT TO THE AREA. MODELS ARE
SHOWING SOME DECENT TIMING DIFFERENCES ON THIS SYSTEM AND WITH THE
COLD AIR ENTRENCHED CAN SEE POTENTIAL FOR A WINTRY MIX WHICH COULD
INCLUDE ICE EARLY IN THE DAY. WITH HIGH UNCERTAINTY THAT FAR OUT
THOUGH WILL LEAVE AS SNOW IN THE MORNING WITH RAIN SNOW MIX
THEREAFTER AS THE WARMER AIR ARRIVES. THURSDAY NIGHT COULD CONTINUE
WITH THE RAIN SNOW MIX IN THE SOUTH AND SNOW IN THE NORTH. ALLBLEND
GENERALLY ACCEPTED. TEMPERATURES SHOULD BE NEAR NORMAL AFTER MONDAY
NIGHT.
&&
.AVIATION /DISCUSSION FOR 151800Z TAF ISSUANCE/...
ISSUED AT 1158 AM EST FRI FEB 15 2013
MAINLY MVFR CONDITIONS AT THE SITES FOR THE FIRST FEW HOURS THIS
AFTERNOON WITH SNOW SHOWERS MOVING THROUGH KLAF AND KIND ON AN
UPPER WAVE. COULD SEE A STRAY FLAKE AT KBMG OR KHUF BUT FOR THE
MOST PART SNOW SHOULD STAY TO THE NORTH. MVFR CEILINGS CAN BE FOUND
TO THE SOUTH THOUGH. RH CROSS SECTIONS INDICATE THAT
CLEARING/SCATTERING OUT COULD OCCUR AROUND 20-21Z IN THE NORTHWEST
AND MOVE ACROSS THE AREA FROM THERE. THESE FIELDS ALSO SHOW CLOUD
COVER FILLING BACK IN AFTER 9Z FROM THE NORTH.
CLOUDS MOVING OUT OF THE NW BY AROUND 21Z AND BACK IN AROUND 9Z AND
OVERSPREADING TO THE SOUTH AND EAST. CLOUD COVER MAY SCATTER UP
SATURDAY AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....CP
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1240 PM EST FRI FEB 15 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 335 AM EST FRI FEB 15 2013
A BROAD UPPER LEVEL LOW WILL SPREAD ACROSS THE GREAT LAKES REGION
THROUGH TOMORROW BRINGING PERIODIC CHANCES FOR LIGHT SNOW SHOWERS.
HIGH PRESSURE WILL THEN BUILD INTO CENTRAL INDIANA BY SUNDAY AS
THE AFOREMENTIONED LOW PUSHES OFF TO THE EAST. AFTER DRY CONDITIONS
ON SUNDAY...ANOTHER UPPER LEVEL LOW WILL BRING PRECIP TO THE
REGION ON MONDAY AND TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1240 PM EST FRI FEB 15 2013
1230 PM UPDATE...CONVECTIVE BANDS OF MODERATE TO HEAVY SNOW IMPACT
THE NORTHERN PORTIONS OF THE FORECAST AREA AT THIS TIME. HAVE BUMPED
UP TO A BRIEF PERIOD OF LIKELY POPS FROM KOKOMO AND TIPTON EAST
THROUGH MUNCIE AND WINCHESTER FOR THE NEXT COUPLE HOURS BASED ON
RADAR TRENDS. BRIEF PERIODS OF HEAVY SNOW DROPPING VISIBILITIES
BELOW 1/2SM IN THE STRONGER SNOW SHOWERS AND CONSIDERING THE
CONVECTIVE NATURE OF THE PRECIP...COULD SEE ICE PELLETS MIX IN
SPORADICALLY. ALSO LIKELY TO SEE QUICK ACCUMS OF A DUSTING TO HALF
INCH WITH THE HEAVIER SNOW SHOWERS...MELTING ONCE SNOW ENDS AS TEMPS
HOVER NEAR FREEZING.
PREVIOUS DISCUSSION FOLLOWS.
SCATTERED LIGHT SNOW AND FLURRIES EXPANDING ACROSS MUCH OF THE
NORTHERN PART OF THE FORECAST AREA SO FAR THIS MORNING AS THE
UPPER WAVE AND ITS ASSOCIATED FORCING MOVE THROUGH. TEMPS ACROSS
THE FORECAST AREA WERE IN THE LOWER AND MID 30S AT 14Z.
FORECAST IN GREAT SHAPE AND HAVE MADE ONLY MINOR ADJUSTMENTS TO
ACCOUNT FOR ONGOING OBS. SCATTERED LIGHT SNOW DEVELOPING A TOUCH
FASTER THAN PREVIOUSLY THOUGHT AS THE STRONGEST FORCING ALOFT
ALREADY INTO THE REGION. EXPECT SNOW SHOWERS TO CONTINUE THROUGH
MID AFTERNOON AS THE UPPER WAVE TRANSITIONS ACROSS THE REGION AND
WILL CONTINUE WITH CHANCE POPS. RAP SOUNDINGS SHOWING SOME WEAK
INSTABILITY DEVELOPING THROUGH EARLY AFTERNOON ALONG WITH
STEEPENING LAPSE RATES UP THROUGH ABOUT 800MB. THIS WILL
CONTRIBUTE TO THE DEVELOPMENT OF A FEW STRONGER CONVECTIVE SNOW
SHOWERS BUT WITH SURFACE TEMPS NEAR TO JUST ABOVE FREEZING AND
LIMITED MOISTURE AVAILABLE...ACCUMULATION POTENTIAL WILL BE
MITIGATED WITH MOST LOCATIONS ONLY SEEING A FEW TENTHS AT BEST.
THE BIGGER IMPACT TO TRAVEL LIKELY TO BE QUICK DROPS IN
VISIBILITIES WITHIN HEAVIER SNOW SHOWERS. MOST PRECIP WILL BE DONE
BY MID AFTERNOON AS THE UPPER WAVE MOVES INTO OHIO. FORECAST HIGHS
IN THE LOW/MID 30S STILL LOOK TO BE ON TRACK.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 335 AM EST FRI FEB 15 2013
DRY CONDITIONS WILL PREVAIL TONIGHT...BUT THE POTENTIAL FOR
PERIODIC SNOW SHOWERS WILL RETURN EARLY SATURDAY MORNING AND
LINGER THROUGH THE DAY AS ANOTHER WEAKER SHORTWAVE PASSES IN THE
UPPER FLOW. WEAK LAKE EFFECT ENHANCEMENT COULD CONTRIBUTE TO SOME
LIGHT SNOW SHOWERS OVER THE NORTHEAST/EASTERN PORTIONS OF CENTRAL
INDIANA THROUGH SATURDAY NIGHT.
HIGH PRESSURE WILL RE-ESTABLISH ITSELF OVER THE AREA ON SATURDAY
NIGHT...RESULTING IN DRY CONDITIONS FOR SUNDAY. MODELS SEEM TO
HAVE A GOOD HANDLE ON THE COOLER AIR ASSOCIATED WITH THE SECOND
WAVE ON SATURDAY...SO STUCK CLOSE TO GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 330 AM EST FRI FEB 15 2013
MAIN FOCUS TO THE EXTENDED WILL BE ON POPS AS TWO SEPARATE SYSTEMS
WILL BRING CHANCES TO CENTRAL INDIANA NEXT WEEK.
LONG RANGE MODELS...INCLUDING THE ENSEMBLES...ARE HAVING SOME
DIFFERENCES HANDING THESE SYSTEMS WITH THE 00Z GEFS AND GFS
GENERALLY QUICKER AND NORTHEAST WITH THE ASSOCIATED LOW PRESSURE
CENTERS AND QPF ACROSS THE FORECAST AREA. THE REGIONAL
INITIALIZATION FORECAST SEEMS TO TAKE A BLEND OF THE EXTENDED OUTPUT
WHICH LOOKS REASONABLE.
A MODEL BLEND WOULD BRING A WARM FRONT ASSOCIATED WITH AN OCCLUDED
SYSTEM ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY A COLD FRONT
MONDAY NIGHT. MODELS BRING MOST OF THE QPF IN MONDAY AFTERNOON AND
NIGHT AND BUFKIT PARTIAL THICKNESS METHOD ALONG WITH SOUNDINGS
SUGGEST ALL RAIN UNTIL AFTER 06Z...WHEN THE RAIN SHOULD MIX WITH OR
TURN TO SNOW FROM NORTHWEST TO SOUTHEAST BEHIND THE COLD FRONT. LEFT
SMALL TUESDAY MORNING SNOW CHANCES IN...BUT THEN HIGH PRESSURE WILL
BUILD IN FROM CENTRAL CANADA LEADING TO DRY AND COLDER WEATHER
THROUGH WEDNESDAY NIGHT. FINALLY...THE 12Z GFS AND GEFS WERE FURTHER
NORTH AND STRONGER BRINGING A STRONG LOW PRESSURE SYSTEM TO CENTRAL
MISSOURI BY 00Z FRIDAY FEBRUARY 22. THE 00Z ECMWF HAD IT MORE
UNORGANIZED ACROSS OKLAHOMA AND ARKANSAS BY THEN. AS A RESULT...NICE
GULF RETURN FLOW HAPPENS A BIT QUICKER IN THE GFS AND GEFS SOLUTIONS
AS DOES QPF BY 18Z MONDAY. AGAIN...WITH MODEL UNCERTAINTY...WILL
ACCEPT THE REGIONAL INITIALIZATION WHICH BRINGS LIKELY POPS
SOUTHWEST HALF ON THURSDAY. BUKFIT PARTIAL THICKNESSES SUGGEST THE
PRECIPITATION WILL START OFF ALL SNOW AND THEN MIX WITH RAIN IN THE
AFTERNOON FROM SOUTHWEST TO NORTHEAST.
WILL NOT MAKE ANY CHANGES TO TEMPERATURES AS OF YET WITH WELL ABOVE
NORMAL HIGHS IN THE 40S AND 50S ON MONDAY FALLING TO NORMAL TO BELOW
NORMAL THE REST OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR 151800Z TAF ISSUANCE/...
ISSUED AT 1158 AM EST FRI FEB 15 2013
MAINLY MVFR CONDITIONS AT THE SITES FOR THE FIRST FEW HOURS THIS
AFTERNOON WITH SNOW SHOWERS MOVING THROUGH KLAF AND KIND ON AN
UPPER WAVE. COULD SEE A STRAY FLAKE AT KBMG OR KHUF BUT FOR THE
MOST PART SNOW SHOULD STAY TO THE NORTH. MVFR CEILINGS CAN BE FOUND
TO THE SOUTH THOUGH. RH CROSS SECTIONS INDICATE THAT
CLEARING/SCATTERING OUT COULD OCCUR AROUND 20-21Z IN THE NORTHWEST
AND MOVE ACROSS THE AREA FROM THERE. THESE FIELDS ALSO SHOW CLOUD
COVER FILLING BACK IN AFTER 9Z FROM THE NORTH.
CLOUDS MOVING OUT OF THE NW BY AROUND 21Z AND BACK IN AROUND 9Z AND
OVERSPREADING TO THE SOUTH AND EAST. CLOUD COVER MAY SCATTER UP
SATURDAY AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1214 PM EST FRI FEB 15 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 335 AM EST FRI FEB 15 2013
A BROAD UPPER LEVEL LOW WILL SPREAD ACROSS THE GREAT LAKES REGION
THROUGH TOMORROW BRINGING PERIODIC CHANCES FOR LIGHT SNOW SHOWERS.
HIGH PRESSURE WILL THEN BUILD INTO CENTRAL INDIANA BY SUNDAY AS
THE AFOREMENTIONED LOW PUSHES OFF TO THE EAST. AFTER DRY CONDITIONS
ON SUNDAY...ANOTHER UPPER LEVEL LOW WILL BRING PRECIP TO THE
REGION ON MONDAY AND TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 940 AM EST FRI FEB 15 2013
SCATTERED LIGHT SNOW AND FLURRIES EXPANDING ACROSS MUCH OF THE
NORTHERN PART OF THE FORECAST AREA SO FAR THIS MORNING AS THE
UPPER WAVE AND ITS ASSOCIATED FORCING MOVE THROUGH. TEMPS ACROSS
THE FORECAST AREA WERE IN THE LOWER AND MID 30S AT 14Z.
FORECAST IN GREAT SHAPE AND HAVE MADE ONLY MINOR ADJUSTMENTS TO
ACCOUNT FOR ONGOING OBS. SCATTERED LIGHT SNOW DEVELOPING A TOUCH
FASTER THAN PREVIOUSLY THOUGHT AS THE STRONGEST FORCING ALOFT
ALREADY INTO THE REGION. EXPECT SNOW SHOWERS TO CONTINUE THROUGH
MID AFTERNOON AS THE UPPER WAVE TRANSITIONS ACROSS THE REGION AND
WILL CONTINUE WITH CHANCE POPS. RAP SOUNDINGS SHOWING SOME WEAK
INSTABILITY DEVELOPING THROUGH EARLY AFTERNOON ALONG WITH
STEEPENING LAPSE RATES UP THROUGH ABOUT 800MB. THIS WILL
CONTRIBUTE TO THE DEVELOPMENT OF A FEW STRONGER CONVECTIVE SNOW
SHOWERS BUT WITH SURFACE TEMPS NEAR TO JUST ABOVE FREEZING AND
LIMITED MOISTURE AVAILABLE...ACCUMULATION POTENTIAL WILL BE
MITIGATED WITH MOST LOCATIONS ONLY SEEING A FEW TENTHS AT BEST.
THE BIGGER IMPACT TO TRAVEL LIKELY TO BE QUICK DROPS IN
VISIBILITIES WITHIN HEAVIER SNOW SHOWERS. MOST PRECIP WILL BE DONE
BY MID AFTERNOON AS THE UPPER WAVE MOVES INTO OHIO. FORECAST HIGHS
IN THE LOW/MID 30S STILL LOOK TO BE ON TRACK.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 335 AM EST FRI FEB 15 2013
DRY CONDITIONS WILL PREVAIL TONIGHT...BUT THE POTENTIAL FOR
PERIODIC SNOW SHOWERS WILL RETURN EARLY SATURDAY MORNING AND
LINGER THROUGH THE DAY AS ANOTHER WEAKER SHORTWAVE PASSES IN THE
UPPER FLOW. WEAK LAKE EFFECT ENHANCEMENT COULD CONTRIBUTE TO SOME
LIGHT SNOW SHOWERS OVER THE NORTHEAST/EASTERN PORTIONS OF CENTRAL
INDIANA THROUGH SATURDAY NIGHT.
HIGH PRESSURE WILL RE-ESTABLISH ITSELF OVER THE AREA ON SATURDAY
NIGHT...RESULTING IN DRY CONDITIONS FOR SUNDAY. MODELS SEEM TO
HAVE A GOOD HANDLE ON THE COOLER AIR ASSOCIATED WITH THE SECOND
WAVE ON SATURDAY...SO STUCK CLOSE TO GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 330 AM EST FRI FEB 15 2013
MAIN FOCUS TO THE EXTENDED WILL BE ON POPS AS TWO SEPARATE SYSTEMS
WILL BRING CHANCES TO CENTRAL INDIANA NEXT WEEK.
LONG RANGE MODELS...INCLUDING THE ENSEMBLES...ARE HAVING SOME
DIFFERENCES HANDING THESE SYSTEMS WITH THE 00Z GEFS AND GFS
GENERALLY QUICKER AND NORTHEAST WITH THE ASSOCIATED LOW PRESSURE
CENTERS AND QPF ACROSS THE FORECAST AREA. THE REGIONAL
INITIALIZATION FORECAST SEEMS TO TAKE A BLEND OF THE EXTENDED OUTPUT
WHICH LOOKS REASONABLE.
A MODEL BLEND WOULD BRING A WARM FRONT ASSOCIATED WITH AN OCCLUDED
SYSTEM ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY A COLD FRONT
MONDAY NIGHT. MODELS BRING MOST OF THE QPF IN MONDAY AFTERNOON AND
NIGHT AND BUFKIT PARTIAL THICKNESS METHOD ALONG WITH SOUNDINGS
SUGGEST ALL RAIN UNTIL AFTER 06Z...WHEN THE RAIN SHOULD MIX WITH OR
TURN TO SNOW FROM NORTHWEST TO SOUTHEAST BEHIND THE COLD FRONT. LEFT
SMALL TUESDAY MORNING SNOW CHANCES IN...BUT THEN HIGH PRESSURE WILL
BUILD IN FROM CENTRAL CANADA LEADING TO DRY AND COLDER WEATHER
THROUGH WEDNESDAY NIGHT. FINALLY...THE 12Z GFS AND GEFS WERE FURTHER
NORTH AND STRONGER BRINGING A STRONG LOW PRESSURE SYSTEM TO CENTRAL
MISSOURI BY 00Z FRIDAY FEBRUARY 22. THE 00Z ECMWF HAD IT MORE
UNORGANIZED ACROSS OKLAHOMA AND ARKANSAS BY THEN. AS A RESULT...NICE
GULF RETURN FLOW HAPPENS A BIT QUICKER IN THE GFS AND GEFS SOLUTIONS
AS DOES QPF BY 18Z MONDAY. AGAIN...WITH MODEL UNCERTAINTY...WILL
ACCEPT THE REGIONAL INITIALIZATION WHICH BRINGS LIKELY POPS
SOUTHWEST HALF ON THURSDAY. BUKFIT PARTIAL THICKNESSES SUGGEST THE
PRECIPITATION WILL START OFF ALL SNOW AND THEN MIX WITH RAIN IN THE
AFTERNOON FROM SOUTHWEST TO NORTHEAST.
WILL NOT MAKE ANY CHANGES TO TEMPERATURES AS OF YET WITH WELL ABOVE
NORMAL HIGHS IN THE 40S AND 50S ON MONDAY FALLING TO NORMAL TO BELOW
NORMAL THE REST OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR 151800Z TAF ISSUANCE/...
ISSUED AT 1158 AM EST FRI FEB 15 2013
MAINLY MVFR CONDITIONS AT THE SITES FOR THE FIRST FEW HOURS THIS
AFTERNOON WITH SNOW SHOWERS MOVING THROUGH KLAF AND KIND ON AN
UPPER WAVE. COULD SEE A STRAY FLAKE AT KBMG OR KHUF BUT FOR THE
MOST PART SNOW SHOULD STAY TO THE NORTH. MVFR CEILINGS CAN BE FOUND
TO THE SOUTH THOUGH. RH CROSS SECTIONS INDICATE THAT
CLEARING/SCATTERING OUT COULD OCCUR AROUND 20-21Z IN THE NORTHWEST
AND MOVE ACROSS THE AREA FROM THERE. THESE FIELDS ALSO SHOW CLOUD
COVER FILLING BACK IN AFTER 9Z FROM THE NORTH.
CLOUDS MOVING OUT OF THE NW BY AROUND 21Z AND BACK IN AROUND 9Z AND
OVERSPREADING TO THE SOUTH AND EAST. CLOUD COVER MAY SCATTER UP
SATURDAY AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
940 AM EST FRI FEB 15 2013
.UPDATE...
THE NEAR TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 335 AM EST FRI FEB 15 2013
A BROAD UPPER LEVEL LOW WILL SPREAD ACROSS THE GREAT LAKES REGION
THROUGH TOMORROW BRINGING PERIODIC CHANCES FOR LIGHT SNOW SHOWERS.
HIGH PRESSURE WILL THEN BUILD INTO CENTRAL INDIANA BY SUNDAY AS
THE AFOREMENTIONED LOW PUSHES OFF TO THE EAST. AFTER DRY CONDITIONS
ON SUNDAY...ANOTHER UPPER LEVEL LOW WILL BRING PRECIP TO THE
REGION ON MONDAY AND TUESDAY.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 940 AM EST FRI FEB 15 2013
SCATTERED LIGHT SNOW AND FLURRIES EXPANDING ACROSS MUCH OF THE
NORTHERN PART OF THE FORECAST AREA SO FAR THIS MORNING AS THE
UPPER WAVE AND ITS ASSOCIATED FORCING MOVE THROUGH. TEMPS ACROSS
THE FORECAST AREA WERE IN THE LOWER AND MID 30S AT 14Z.
FORECAST IN GREAT SHAPE AND HAVE MADE ONLY MINOR ADJUSTMENTS TO
ACCOUNT FOR ONGOING OBS. SCATTERED LIGHT SNOW DEVELOPING A TOUCH
FASTER THAN PREVIOUSLY THOUGHT AS THE STRONGEST FORCING ALOFT
ALREADY INTO THE REGION. EXPECT SNOW SHOWERS TO CONTINUE THROUGH
MID AFTERNOON AS THE UPPER WAVE TRANSITIONS ACROSS THE REGION AND
WILL CONTINUE WITH CHANCE POPS. RAP SOUNDINGS SHOWING SOME WEAK
INSTABILITY DEVELOPING THROUGH EARLY AFTERNOON ALONG WITH
STEEPENING LAPSE RATES UP THROUGH ABOUT 800MB. THIS WILL
CONTRIBUTE TO THE DEVELOPMENT OF A FEW STRONGER CONVECTIVE SNOW
SHOWERS BUT WITH SURFACE TEMPS NEAR TO JUST ABOVE FREEZING AND
LIMITED MOISTURE AVAILABLE...ACCUMULATION POTENTIAL WILL BE
MITIGATED WITH MOST LOCATIONS ONLY SEEING A FEW TENTHS AT BEST.
THE BIGGER IMPACT TO TRAVEL LIKELY TO BE QUICK DROPS IN
VISIBILITIES WITHIN HEAVIER SNOW SHOWERS. MOST PRECIP WILL BE DONE
BY MID AFTERNOON AS THE UPPER WAVE MOVES INTO OHIO. FORECAST HIGHS
IN THE LOW/MID 30S STILL LOOK TO BE ON TRACK.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 335 AM EST FRI FEB 15 2013
DRY CONDITIONS WILL PREVAIL TONIGHT...BUT THE POTENTIAL FOR
PERIODIC SNOW SHOWERS WILL RETURN EARLY SATURDAY MORNING AND
LINGER THROUGH THE DAY AS ANOTHER WEAKER SHORTWAVE PASSES IN THE
UPPER FLOW. WEAK LAKE EFFECT ENHANCEMENT COULD CONTRIBUTE TO SOME
LIGHT SNOW SHOWERS OVER THE NORTHEAST/EASTERN PORTIONS OF CENTRAL
INDIANA THROUGH SATURDAY NIGHT.
HIGH PRESSURE WILL RE-ESTABLISH ITSELF OVER THE AREA ON SATURDAY
NIGHT...RESULTING IN DRY CONDITIONS FOR SUNDAY. MODELS SEEM TO
HAVE A GOOD HANDLE ON THE COOLER AIR ASSOCIATED WITH THE SECOND
WAVE ON SATURDAY...SO STUCK CLOSE TO GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 330 AM EST FRI FEB 15 2013
MAIN FOCUS TO THE EXTENDED WILL BE ON POPS AS TWO SEPARATE SYSTEMS
WILL BRING CHANCES TO CENTRAL INDIANA NEXT WEEK.
LONG RANGE MODELS...INCLUDING THE ENSEMBLES...ARE HAVING SOME
DIFFERENCES HANDING THESE SYSTEMS WITH THE 00Z GEFS AND GFS
GENERALLY QUICKER AND NORTHEAST WITH THE ASSOCIATED LOW PRESSURE
CENTERS AND QPF ACROSS THE FORECAST AREA. THE REGIONAL
INITIALIZATION FORECAST SEEMS TO TAKE A BLEND OF THE EXTENDED OUTPUT
WHICH LOOKS REASONABLE.
A MODEL BLEND WOULD BRING A WARM FRONT ASSOCIATED WITH AN OCCLUDED
SYSTEM ACROSS CENTRAL INDIANA ON MONDAY FOLLOWED BY A COLD FRONT
MONDAY NIGHT. MODELS BRING MOST OF THE QPF IN MONDAY AFTERNOON AND
NIGHT AND BUFKIT PARTIAL THICKNESS METHOD ALONG WITH SOUNDINGS
SUGGEST ALL RAIN UNTIL AFTER 06Z...WHEN THE RAIN SHOULD MIX WITH OR
TURN TO SNOW FROM NORTHWEST TO SOUTHEAST BEHIND THE COLD FRONT. LEFT
SMALL TUESDAY MORNING SNOW CHANCES IN...BUT THEN HIGH PRESSURE WILL
BUILD IN FROM CENTRAL CANADA LEADING TO DRY AND COLDER WEATHER
THROUGH WEDNESDAY NIGHT. FINALLY...THE 12Z GFS AND GEFS WERE FURTHER
NORTH AND STRONGER BRINGING A STRONG LOW PRESSURE SYSTEM TO CENTRAL
MISSOURI BY 00Z FRIDAY FEBRUARY 22. THE 00Z ECMWF HAD IT MORE
UNORGANIZED ACROSS OKLAHOMA AND ARKANSAS BY THEN. AS A RESULT...NICE
GULF RETURN FLOW HAPPENS A BIT QUICKER IN THE GFS AND GEFS SOLUTIONS
AS DOES QPF BY 18Z MONDAY. AGAIN...WITH MODEL UNCERTAINTY...WILL
ACCEPT THE REGIONAL INITIALIZATION WHICH BRINGS LIKELY POPS
SOUTHWEST HALF ON THURSDAY. BUKFIT PARTIAL THICKNESSES SUGGEST THE
PRECIPITATION WILL START OFF ALL SNOW AND THEN MIX WITH RAIN IN THE
AFTERNOON FROM SOUTHWEST TO NORTHEAST.
WILL NOT MAKE ANY CHANGES TO TEMPERATURES AS OF YET WITH WELL ABOVE
NORMAL HIGHS IN THE 40S AND 50S ON MONDAY FALLING TO NORMAL TO BELOW
NORMAL THE REST OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 151500Z TAF UPDATE/...
ISSUED AT 940 AM EST FRI FEB 15 2013
CEILINGS OSCILLATING BETWEEN 1500 AND 3000 FT AT ALL TERMINALS
ALREADY THIS MORNING...WITH LIGHT SNOW SHOWERS AND FLURRIES
EXPANDING ACROSS THE NORTHERN COUNTIES. HAVE INCLUDED A MENTION OF
5SM -SN AT BOTH KIND AND KLAF IN TEMPO GROUPS FOR THE NEXT FEW
HOURS AS THE UPPER LEVEL DISTURBANCE PASSES THROUGH THE REGION.
WINDS WILL VEER TO A NORTHWEST DIRECTION BY MIDDAY AND CONTINUE
INTO THE AFTERNOON. REST UNCHANGED.
12Z DISCUSSION FOLLOWS.
ELONGATED UPPER LEVEL DISTURBANCE WILL DROP SOUTHEAST ACROSS THE
TERMINALS TODAY PERHAPS TRIGGERING A FEW SNOW SHOWERS THIS MORNING
ENDING AFTER 16Z AT LAF. HOWEVER...LITTLE IN THE WAY SHOWING UP ON
UPSTREAM OBSERVATIONS AND MOISTURE CONFINED TO BELOW 750
MILLIBARS...SO WILL LEAVE THE TAFS DRY. SOME MVFR CEILINGS WERE
ACROSS NORTHERN ILLINOIS AND NOW LAF AND WILL SETTLE SOUTHEAST BUT
BECOME VFR ONCE AGAIN AFTER THE UPPER WAVE AND SNOW THREAT PASSES.
WOULD NOT RULE OUT A FEW LAKE EFFECT SNOW SHOWERS OVERNIGHT TONIGHT
AT IND AND LAF...BUT CHANCES TOO LOW TO MENTION.
NORTHWEST WINDS AROUND 10 KNOTS TODAY WILL BE LESS THAN 10 KNOTS
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...RYAN
SHORT TERM...TDUD
LONG TERM....MK
AVIATION...MK/RYAN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1143 PM CST THU FEB 14 2013
.SHORT TERM /TONIGHT/...
FORECAST CONCERN IS FOCUSED ON QUICK MOVING SHORTWAVE TO BRING SOME
LIGHT PRECIP TO THE FORECAST AREA THROUGH THIS EVENING. WEAK BROAD
FORCING ALONG THE COLD FRONT WILL BRING LIGHT SNOW OR RAIN THROUGH
THE LATE AFTERNOON BEFORE SWITCHING OVER TO ALL SNOW AFTER 00Z
FRIDAY. BUFR SOUNDINGS SHOWING BRIEF WINDOW OF FAIRLY DEEP
SATURATION FROM 21Z OR CURRENTLY THROUGH 03Z FRIDAY. COLUMN LOSES
ICE INTRODUCTION AND FORCING ACROSS NORTHERN IOWA B/T 00-03Z.
BELIEVE MODELS ARE BIT SLOW WITH MOVING THIS SYSTEM OUT AND CUT BACK
ON POPS PAST 03Z. 17Z HRRR QUICKLY DIMINISHES PRECIP BY 02Z WHICH
COINCIDES WITH SEVERAL OF THE HIRES WRF MODELS AND NAM12. ALSO
DECREASED SNOW AMOUNTS WITH THE QUICKER MOVEMENT...WEAKER FORCING
AND LESS MOISTURE AVAILABLE.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
COLD AIR SETTLING INTO THE REGION BY 12Z FRIDAY WITH GENERALLY A
CLOUDY DAY IN STORE. LINGERING FLURRIES WILL BE POSSIBLE FRIDAY WITH
WEAK WAVE PASSING THROUGH THE REGION DURING THE DAYTIME HOURS.
OTHERWISE TEMPERATURES WILL CREEP BACK UP DURING THE DAY TO NEAR 20
NORTH AND THE LOWER 30S IN THE SOUTH. AS HIGH BUILDS SOUTH FRIDAY
NIGHT SKIES WILL CLEAR OUT AND COLDER NIGHT IN STORE. LOWS WILL DROP
OFF INTO THE SINGLE DIGITS NORTH WITH THE TEENS IN THE SOUTHEAST.
H850 TEMPS REMAIN RATHER COLD THROUGH THE EARLY PART OF THE FORECAST
BUT AS THE RIDGE AXIS SLIPS EAST SATURDAY EVENING...TEMPS WARM
OVERNIGHT INTO SUNDAY MORNING. WARM AIR ADVECTION WILL INITIATE
CLOUDS WITH GENERALLY LIGHT FLOW OVERNIGHT. BY SUNDAY MED RANGE
MODELS CONTINUE WITH PREVIOUS RUNS TO SHOW DECENT WARM UP BY LATE
DAY. H850 TEMPS WARM TO NEAR 0C NORTHEAST AND TO NEAR 4-5C SOUTHWEST
AND WEST BY 00Z. THIS BODES WELL FOR TRENDS OF HIGHS IN THE 50S
ACROSS THE SOUTHWEST PORTION OF THE FORECAST AREA WITH HIGHS ABOVE
THE FREEZING MARK IN THE NORTHEAST. AS THE NEXT UPSTREAM WAVE
APPROACHES THE AREA ANOTHER STRONG COLD FRONT WILL PASS SOUTHEAST
THROUGH IOWA ON MONDAY. LIFT ASSOCIATED WITH IT WILL ALLOW FOR A
RAIN OR RAIN/SNOW MIXTURE TO OCCUR SOUTHEAST BY LATE IN THE
AFTERNOON. ANOTHER STRETCH OF COLDER THAN NORMAL WEATHER IS
ANTICIPATED FOR THE EARLY PORTION OF NEXT WEEK WITH A SLOW
MODERATION TOWARD THURSDAY...BUT STILL BELOW THE FREEZING MARK. MED
RANGE MODELS STILL PAINT AN ACTIVE STORM OVER THE FORECAST AREA BY
LATE WED OR EARLY THURSDAY WITH THE MAIN PORTION OF THE STORM TO HIT
THURSDAY THROUGH FRIDAY. SIGNATURE HAS SHOWN UP FOR TWO DAYS NOW IN
MOST MED RANGE MODELS...BUT EVEN SO...AT SEVEN DAYS OUT THERE ARE
STILL TO BE MANY CHANGES IN THE TRACK AND DETAILS. AT THIS TIME WILL
EMPHASIZE ONLY A STRONGER SYSTEM OVER THE CENTRAL STATES LOOKS MORE
LIKELY BUT WAY TOO EARLY TO BECOME OVERLY EXCITED ABOUT MODEL
DETAILS...ESPECIALLY GIVEN THAT THE 12Z GFS IS ABOUT 10 MB STRONGER
THAN THE 12Z EURO MODEL TODAY.
&&
.AVIATION...15/06Z
CLOUDS AND COLD FRONT HAVE MOVED SOUTH OF IA AND WINDS WILL DIMINISH
EARLY IN THE TAF PERIOD. ANOTHER SHORT WAVE WILL DROP SOUTHEAST
ACROSS IA ON FRI BRINGING WITH IT LOCAL MVFR/IFR CONDITIONS IN CIG
AND -SHSN TO THE NORTHERN TAF SITES. EXPECT THE SRN SITES TO REMAIN
VFR WITH ISOLATED -SHSN DURING THE DAY. CLEARING OVERSPREADING THE
STATE FRI EVE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MS FEB 13
LONG TERM...REV
AVIATION...MS FEB 13
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 PM CST THU FEB 14 2013
.AVIATION...
A FAST MOVING UPPER LEVEL DISTURBANCE IN NORTHERN ILLINOIS IS
MOVING EAST BRINGING CLEARING SKIES. NORTHWEST WINDS OF 10 TO 20
KTS WILL GRADUALLY LOWER TO AROUND 10 TO 15 KTS ON FRIDAY AS
CANADIAN HIGH PRESSURE MOVES IN FROM THE DAKOTAS.
NICHOLS
&&
.PREV DISCUSSION... /ISSUED 320 PM CST THU FEB 14 2013/
SYNOPSIS...
18Z SURFACE ANALYSIS INDICATED LOW PRESSURE OVER NORTHERN LOWER MI
WITH A TROUGH OR WEAK COLD FRONT REACHING SOUTH-SOUTHWEST ACROSS
IL...MO INTO EASTERN OK. A SECOND REINFORCING COLD FRONT EXTENDED
WEST FROM THE LOW ACROSS WI TO ALONG THE IA/MN BORDER. SOUTH OF THIS
FRONT...TEMPERATURES WERE IN THE 30S TO LOWER 40S WITH BRISK W-NW
WINDS ACROSS THE FORECAST AREA. ALOFT...A BROAD CYCLONIC FLOW
ENCOMPASSED THE EASTERN 2/3RDS OF THE CONTINENTAL U.S. THERE WERE A
SERIES OF SHORTWAVES EMBEDDED IN THIS FLOW FROM THE GREAT LAKES TO
THE CANADIAN ROCKIES. THE FOCUS IN THE SHORT TERM IS A VORT MAX
EVIDENT ON SATELLITE WV IMAGES OVER N CENTRAL IA...WHERE AREA RADARS
AND SURFACE REPORTS WERE INDICATING SNOW SHOWERS.
SHORT TERM...TONIGHT AND FRIDAY...
MAIN FOCUS IS ON THE SNOW SHOWERS THAT WILL OVERSPREAD THE AREA
LATE THIS AFTERNOON AND EVENING...THEN COOLER TEMPERATURES AND
POTENTIAL FLURRIES THROUGH FRIDAY.
AN AXIS OF ROTATION SEEN IN RECENT KDMX 88D LOOPS INDICATED THE
UPSTREAM VORT MAX WAS CENTERED ROUGHLY NORTH OF WEBSTER CITY AT 20Z.
THIS WAS WELL SOUTH OF THE OPERATIONAL NAM...GFS AND ECMWF TRACKS
FROM THIS MORNING. THE RECENT RAP RUNS APPEARED TO HAVE A DECENT
CAPTURE OF THIS VORT CENTER AND WILL FOLLOW ITS OVERALL
SOUTHEASTWARD TRACK. THIS WILL SEND THE UPSTREAM SNOW SHOWERS...
TRENDING HEAVIEST ALONG AND NORTH OF THE VORT MAX...SOUTHEAST
THROUGH THE EAST CENTRAL IA AND THEN W CENTRAL IL OVER THE NEXT
SEVERAL HOURS. COLD ADVECTION ALOFT WAS SHOWN LEADING TO STEEP MID
LEVEL LAPSE RATES ON THE ORDER OF 7 TO 8 DEG C/KM IN THIS MORNING/S
MODEL RUNS. THIS...COMBINED WITH THE UPPER LEVEL FORCING AND LIFT
ALONG THE SOUTHWARD MOVING COLD FRONT WILL SUPPORT CONTINUED LIGHT
TO MODERATE SNOW SHOWERS AND AT LEAST LIGHT ACCUMULATIONS. THE HIGH
RES RAP CONTINUES TO INDICATE QPF VALUES IN THE RANGE OF .2 TO .3
INCHES AS SNOW SHOWERS TRACK FROM ABOUT CID THROUGH THE QUAD CITIES
TO NEAR KEWANEE BETWEEN 23Z AND 05Z AND HAVE LIKELY POPS ALONG THIS
AXIS. WHILE THIS LOOKS OVERDONE BASED ON MEAGER PRECIPITATION
AMOUNTS REPORTED SO FAR AT AUTOMATED UPSTREAM SITES...CANNOT RULE
OUT BANDS OF 1 TO POSSIBLY 2 INCH SNOW ACCUMULATIONS IF THE
CONVECTION TAPS INTO THE DEEPER INSTABILITY OVER THE NEXT SEVERAL
HOURS. BASED ON THE INITIAL WARM LOW LEVELS AND TEMPERATURES IN
THE 30S TO LOWER 40S LEADING TO A RAIN/SNOW MIX AT ONSET...WILL
STAY CLOSE TO A MORE CONSERVATIVE .5 TO 1 INCH SNOWFALL RANGE FOR
NOW AND WATCH TRENDS CLOSELY.
THE CURRENT PACE OF THE VORT MAX SHOULD SEND THE SHOWERS EAST OF THE
AREA BY MID EVENING...AND HAVE ONLY SLIGHT CHANCE POPS AFTER
MIDNIGHT IN THE EAST AND SOUTHEAST. THE COLD FRONT SHOULD SLIDE
THROUGH THE ENTIRE AREA BY MIDNIGHT...FOLLOWED BY PARTIAL CLEARING
BASED ON SATELLITE TRENDS. GUIDANCE LOWS BY SUNRISE IN THE MID TEENS
NORTH TO MID 20S SOUTH LOOK REASONABLE.
FRIDAY...WILL KEEP A MENTION OF SCATTERED FLURRIES GOING IN THE
FORECAST BASED ON THE STREAM OF WEAK IMPULSES AND MID LEVEL MOISTURE
IN THE CYCLONIC FLOW ALOFT. CLOUD COVER AND COLD AIR ADVECTION
SHOULD LIMIT THE DIURNAL TEMPERATURE RISE. HAVE STAYED CLOSE TO
THE PREVIOUS FORECAST AND LATEST MODEL GUIDANCE WITH HIGHS
RANGING FROM THE LOWER 20S NORTH TO LOWER 30S SOUTH.
SHEETS
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
FRIDAY NIGHT AND SATURDAY WE REMAIN IN THE NORTHWEST CYCLONIC FLOW
AND STEEP MID LEVEL LAPSE RATES WITH ENOUGH LOW LEVEL MOISTURE TO
ALLOW FOR FLURRIES DURING THE OVERNIGHT AND SATURDAY MORNING. WE
ALSO HAVE SOME UPPER LEVEL VORT MAXES THAT SHOULD ALSO HELP TO
TRIGGER THESE FLURRIES. THERE IS NOT REALLY ENOUGH MOISTURE FOR MORE
THAN THAT...THOUGH A DUSTING IS POSSIBLE IF REPEAT ACTIVITY AFFECTS
THE SAME AREA. TEMPERATURES TO REMAIN COLD THROUGH SATURDAY WITH
HIGHS SATURDAY IN THE 20S TO AROUND 30. WARMED MINS FRIDAY NIGHT DUE
TO THE EXTRA CLOUD COVER AND RANGE FROM 10-20.
STRONG WARM AIR ADVECTION SETS IN OVER THE AREA AT 850MB SATURDAY
NIGHT AND SUNDAY. THIS IS LIKELY TO BRING ANOTHER BAND OF CLOUD
COVER ACROSS THE AREA OVERNIGHT AND SUNDAY MORNING. SATURDAY NIGHT
MINS ARE LIKELY TO NOT SHOW MUCH CHANGE YET AS MOST OF THE WARMING
IS ALOFT. SUNDAY HOWEVER WE ARE LIKELY TO SEE A BIG WARM-UP WITH
HIGHS IN THE MID 30S NORTHEAST TO THE UPPER 40S SOUTHWEST.
TEMPERATURES APPROACHING 50 ARE POSSIBLE IF WE CAN CLEAR OUT AND MIX
DEEPLY ENOUGH.
THE NEXT PUZZLE OF THE DAY IS MONDAY AND MONDAY NIGHT AS OUR NEXT
STRONG STORM SYSTEM CROSSES THE MIDWEST. A RELATIVELY SHALLOW
LONGWAVE TROUGH MOVES ACROSS THE AREA WITH TWO SEPARATE PIECES OF
ENERGY...ONE FARTHER NORTH THAT GENERATES A SURFACE LOW OVER
SOUTHERN MINNESOTA BY MONDAY MORNING. ANOTHER PIECE OF ENERGY IS
OVER NEW MEXICO WHICH GENERATES A SURFACE LOW OVER OKLAHOMA AT THE
SAME TIME. THIS SYSTEM SWEEPS OUT ACROSS THE MIDWEST MONDAY AND
MONDAY NIGHT. MODELS HAVE BEEN VARYING ON HOW WELL PHASED THESE
SYSTEMS WILL BE OVER THE PAST COUPLE DAYS AS WELL AS HOW MUCH ENERGY
WILL BE WITH EACH. THUS...THE IMPACT FOR OUR CWA HAS VARIED FROM
DRY TO A RAIN/SNOW MIX. FOR NOW MODELS ARE COMING IN A LITTLE
SLOWER AND STRONGER...AND ARE BRINGING MORE MOISTURE AND WARMTH INTO
THE AREA. THUS...HAVE RAISED POPS THROUGH THE PERIOD. ALSO...HAVE
CONVERTED MONDAY TO NEARLY ALL RAIN...WITH JUST A RAIN SNOW MIX
ACROSS THE NORTH. MONDAY NIGHT WE GRADUALLY SWITCH TO ALL
SNOW...BUT THE TIMING IS STILL VERY MUCH UP IN THE AIR. DUE TO THE
START BEING ALL RAIN...SNOWFALL AMOUNTS WILL BE LIGHT.
TUESDAY AND WEDNESDAY ARE RELATIVELY QUIET WITH A STRONG SURFACE
RIDGE BUILDING INTO THE AREA FOR DRY AND COLD CONDITIONS. IN
FACT...IF WE CAN GET DECENT RADIATIONAL CONDITIONS FOR TUESDAY NIGHT
MIN TEMPS COULD DIP INTO THE SINGLE DIGITS OVER A FAIRLY LARGE
PORTION OF THE AREA. HOWEVER...THIS IS STILL SOMEWHAT QUESTIONABLE
AND HAVE STAYED A LITTLE WARMER FOR NOW.
THE BIG QUESTION OF THE FORECAST COMES THURSDAY. FOR SEVERAL MODEL
RUNS NOW...THE ECMWF AND GFS HAVE BEEN ADVERTISING A VERY STRONG
STORM FOR THE MIDWEST ON THURSDAY AND FRIDAY. THERE IS REMARKABLE
CONSISTENCY AND CONFIDENCE IS GROWING THAT SOMEWHERE IN THE MIDWEST
THERE WILL BE A MAJOR WINTER STORM...IF NOT A BLIZZARD.
HOWEVER...WHETHER OUR AREA WILL BE AFFECTED OR NOT IS VERY MUCH IN
QUESTION. WE CURRENTLY HAVE DIFFERING MODEL SOLUTIONS...ONE OF WHICH
DEPICTS THE WINTER STORM AFFECTING THE CWA WITH MAJOR SNOW
ACCUMULATIONS...ANOTHER WHICH BRINGS IN MORE WARM AIR AND AFFECTS US
WITH ANOTHER RAIN/SNOW MIX EVENT WITH LESSER ACCUMULATIONS. IN
GENERAL PREFER THE MORE CONSISTENT AND BETTER VERIFYING ECMWF WHICH
HAS THE LARGER SNOW ACCUMULATIONS...BUT CANNOT TOTALLY DISCOUNT THE
WARMER GFS EITHER. WE WILL HAVE TO WATCH THIS STORM VERY CAREFULLY
OVER THE NEXT SEVERAL DAYS TO MONITOR THESE TRENDS. YOU WILL
DEFINITELY WANT TO KEEP UP WITH THE LATEST INFORMATION REGARDING
THIS WINTER STORM SYSTEM. FOR NOW THE LATEST FORECAST REFLECTS A
BLENDED APPROACH...AND WE WILL HAVE TO REFINE WITH LATER FORECASTS.
LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
311 PM CST FRI FEB 15 2013
.DISCUSSION...
12Z UPPER AIR DATA DEPICTED AT 130KT JET DIVING SOUTH OUT OF WESTERN
SASKATCHEWAN WITH WIDESPREAD 500MB TEMPS OF AROUND -40C OVER THE
NORTHERN PLAINS AND EASTERN CANADA. AN UPPER LEVEL TROF WAS MAKING
SOUTHWARD PROGRESS OUT OF THE WESTERN DAKOTAS IN RECENT HOURS PER
WATER VAPOR IMAGERY. WEAK RADAR RETURNS HAVE DEVELOPED OVER MUCH OF
NORTHERN KANSAS THOUGH DEWPOINT DEPRESSIONS AROUND 20F ARE LIKELY
KEEP MUCH OF THIS WEAK ACTIVITY FROM REACHING THE GROUND. 20Z
SURFACE-3KM LAPSE RATES NEAR 9C/KM WERE NOTED IN CENTRAL
NEBRASKA...WITH AROUND 8C/KM VALUES EAST AND ALSO SOUTHEAST INTO THE
LOCAL AREA.
THE MAIN ISSUES TONIGHT ARE WHERE AND HOW LONG THE SNOW SHOWERS WILL
LAST. THE VARIOUS GUIDANCE ALL POINTS TO A MORE SUSTAINED AREA OF
PRECIPITATION SOMEWHERE IN NORTHEAST KANSAS...WITH THE DETAILS THE
MAIN ISSUE. AS THE UPPER TROF CONTINUES SOUTH TO SOUTHEAST...THE
LAPSE RATES REMAIN NEAR 8C/KM WELL INTO THE NIGHT AS FRONTOGENESIS
AROUND 750MB INCREASES AND FOCUSES ON THE NORTHEAST TIP OF A
DEVELOPING THETA-E RIDGE AT THIS LEVEL...RESULTING IN GOOD LIFT
THROUGH THE DENDRITIC GROWTH ZONE. THE MOST RECENT HRRR AND RAP DATA
HAS BEEN PUSHING THIS AREA NORTHEAST...FAVORING FAR NORTHEAST KANSAS
MAINLY AROUND 03Z. HAVE INCREASED CHANCES AND AMOUNTS UP HERE...BUT
STILL LIMITED MOISTURE AND THE COVERAGE OF ANY BANDS AND EXACTLY
WHERE THIS WILL END UP KEEPS CHANCES BELOW LIKELY LEVELS. SOME BRIEF
MODERATE SNOWFALLS CAN BE EXPECTED IN THE HEAVIEST PRECIPITATION...
AND LOCAL AMOUNTS NEAR AN INCH SEEM PLAUSIBLE. ANY ACCUMULATING SNOW
SHOULD END WELL BEFORE SUNRISE AS THE UPPER TROF SWINGS INTO THE
MISSISSIPPI VALLEY. WESTERN AREAS SEE A QUICKLY DRYING TROPOSPHERE
THIS EVENING...BUT HIGH CLOUD RETURNS THERE LATE TONIGHT AS WARM AIR
ADVECTION ENSUES FROM THE UPPER PATTERN SHIFTING EAST. THOUGH
INSOLATION WILL BE LIMITED AS THE CLOUDS DEEPEN SATURDAY...SOUTHWEST
WINDS SHOULD SUPPORT TEMPS SEVERAL DEGREES ABOVE TODAYS LEVELS FOR
CENTRAL AND WESTERN LOCATIONS.
65
SHORTWAVE RIDGING AND WARM AIR ADVECTION IS EXPECTED TO BRING WARMER
TEMPS AND SUNNY SKIES TO THE AREA FOR SUNDAY. THEN THE NEXT
SHORTWAVE IS EXPECTED TO MOVE ACROSS THE CENTRAL AND NORTHERN PLAINS
BRINGING A COLD FRONT THROUGH THE AREA LATE SUNDAY NIGHT AND MONDAY
MORNING. MODELS CONTINUE TO SHOW THE BETTER MOISTURE TO THE EAST OF
THE FORECAST AREA. AND WITH THE FRONT PUSHING INTO MO BY THE LATE
MORNING HOURS...PRECIP CHANCES SHOULD BE CONFINED TO FAR EASTERN KS
DURING THE DAY MONDAY.
TUESDAY AND WEDNESDAY LOOK TO BE IN BETWEEN SYSTEMS WITH SURFACE
RIDGING BUILDING SOUTH THROUGH THE PLAINS. THIS SHOULD KEEP TEMPS
FROM WARMING UP VERY MUCH. THE NEXT BIG WEATHER MAKER LOOKS TO
IMPACT THE REGION WEDNESDAY NIGHT AND THURSDAY. BOTH THE GFS AND
ECMWF HAVE TRENDED SLIGHTLY SLOWER WITH THE UPPER CLOSED LOW AS IT
MOVES OUT OF THE SOUTHERN ROCKIES. HOWEVER THE GFS REMAINS SLIGHTLY
FASTER THAN THE GFS. THE OTHER TREND OF NOTE IS THE ECMWF FURTHER
NORTH WITH THE TRACK OF THE LOW PRESSURE SYSTEM. THIS COMPLICATES
THE FORECAST OF PRECIP TYPE QUITE A BIT. INITIALLY WITH THE COLD
SURFACE RIDGE IN PLACE WEDNESDAY...GFS FORECAST SOUNDINGS SUPPORT
ALL SNOW WEDNESDAY EVENING. HOWEVER BOTH MODELS SHOW STRONG WARM AIR
ADVECTION ALOFT AND A WARM NOSE DEVELOPING THROUGH THE NIGHT WITH
SURFACE TEMPS REMAINING IN THE 20S AND LOWER 30S. AS THE WARM AIR
ADVECTION DEVELOPS...FREEZING RAIN AND SLEET BECOME POSSIBLE WHILE
SURFACE TEMPS ARE BELOW FREEZING. ON TOP OF THIS IS THE POTENTIAL
FOR MID LEVEL DRY AIR TO WRAP UP IN THE SYSTEM AND FOR THE SOUNDINGS
TO LOOSE SATURATION WITHIN THE DENDRITIC GROWTH LAYER ADDING TO THE
POTENTIAL FOR FREEZING RAIN. REALLY THE TRACK OF THE SYSTEM DOES NOT
FAVOR AN ALL SNOW EVENT FOR THE BULK OF THE FORECAST AREA.
CONFIDENCE IN TRYING TO NAIL DOWN PRECIP TYPE IS VERY LOW AT THIS
POINT GIVEN THAT IT IS 6 DAYS OUT...BUT THINK THAT THE PROBABILITY
OF MIX WINTRY PRECIP IS HIGH ENOUGH THAT IT SHOULD BE MENTIONED IN
THE FORECAST. ONE SHOULD NOT GET CAUGHT UP ON WHERE THE FORECAST HAS
THE RAIN/SNOW LINE /WHICH IS LIKELY TO FLUCTUATE IN THE COMING
DAYS/...BUT THAT THERE IS THE POTENTIAL FOR A MIXED BAG OF PRECIP.
THINGS THAT COULD CHANGE THIS IS IF THE MAGNITUDE OF LOW LEVEL WARM
AIR ADVECTION WERE TO INCREASE AND RAISE SURFACE TEMPS ABOVE
FREEZING OR IF THE STORM SYSTEM TRENDS SOUTH AGAIN. IN ANY CASE IT
LOOKS TO BE MESSY.
WOLTERS
&&
.AVIATION...
CONFIDENCE IS NOT HIGH...BUT THERE CONTINUES TO BE INDICATIONS OF
SMALL AREAS OF SNOW DEVELOPING AFTER 23Z...WITH THE HEART AROUND
04Z AND IN THE KTOP AND KFOE VICINITY. THE MAIN ISSUES ARE JUST WHERE
THE SMALL AREAS WILL FORM AND HOW LOW CONDITIONS WILL GET. ENOUGH
CONFIDENCE EXISTS FOR A TEMPORARY IFR FORECAST FOR KTOP AND KFOE
WHEN THE SNOW SHOULD BE THE HEAVIEST.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
619 PM EST SAT FEB 16 2013
...Updated Aviation Discussion...
.Short Term (Now - Sunday)...
Issued at 310 PM EST Sat Feb 16 2013
An upper-level trough axis is currently passing over the forecast
area as it heads toward the east coast. With cold air advection,
temperatures struggled to rise this afternoon. Most places have
managed to at least reach the freezing mark and areas with more sun
have pushed mid 30s. As expected, snow showers developed along the
windward side of the Appalachians early this afternoon. These
showers will continue to push east with the trough and dissipate as
sunset nears.
Ridging at the surface and aloft will build across the Ohio Valley
starting tonight and shift east through the day Sunday. With the
center of the surface high passing by to our south, expect our
current breezy northwest winds to weaken and transition to westerly
for tomorrow and southerly by tomorrow night. Generally light winds
and partly cloudy skies tonight will allow temperatures to bottom
out in the mid teens to low 20s. Believe some low-level clouds will
build across at least a portion of the forecast area overnight,
which will keep some locations from reaching full radiational
cooling potential. Right now, have stretched this anticipated band
of clouds southeastward from Orange/Dubois counties in Indiana to
the Lake Cumberland region mainly after midnight, which is supported
by most hires guidance. There is some uncertainty to just how thick
the cloud deck will be, but this is where temps in the lower 20s are
likely. Of course, any shift in this cloud band will cause a shift
in temperatures as well. These clouds will quickly clear after
daybreak. A warming trend will commence tomorrow as increasing
temperatures/heights aloft, light west surface winds, and mostly
sunny skies push high temperatures to the middle 30s across the
Lexington area and to middle 40s across the Bowling Green area.
.Long Term (Sunday Night - Saturday)...
Issued at 300 PM EST Sat Feb 16 2013
Progressive longwave pattern aloft through the coming week will
provide a little bit of everything, with two main weathermakers on
Monday night and Thursday-Friday.
Modifying Canadian surface high will start to retreat east of
Kentucky on Sunday night, allowing return flow to start to develop.
However, we do expect a strong enough inversion that the effects
will be mostly aloft, so temps will still be near normal even after
leveling off by about midnight.
Monday will be unseasonably mild and breezy with the southerly flow
well established, and much of the day to warm up ahead of the
incoming precip shield. Most noticeable feature will be south winds
at a solid 20 mph with gusts in the 30s. This is below advisory
criteria but will keep the mention in the HWO. Max temps should be a
solid 10 degrees above climo. Will start to see showers ahead of the
front, with POPs ramping up in the afternoon, mainly west of I-65.
Look for a clean FROPA on Monday night, with categorical POPs and
QPF on the order of a half inch. Will be mild enough not to have
precip type issues, and stable enough to minimize any chance of
thunder. Can`t rule out some gusty showers, but even that is an
outside shot in the stable environment.
Minimal recovery in the cold advection on Tuesday as a 1040mb
Canadian high builds south toward Lake Superior. However, the
coldest air will remain bottled up in the Great Lakes and Canada,
with shortwave upper ridging over the Ohio Valley. Temps slightly
below normal, but by no means Arctic for Tue-Thu.
Next system will eject out of the southern Rockies on Thursday, but
will occlude over the Plains as a block develops along the East
Coast. The Ohio Valley will be in for stratiform warm frontal
precip, especially Thursday night where we will carry likely POPs.
Thermal profiles will be marginal, especially in our northern
counties. Expect it to be a race between the warmth and the
moisture, and confidence in the precip type forecast is quite low.
Temps will start below freezing throughout the area Thursday
morning, but it could take most of the day to saturate the column.
If precip arrives too quickly we could be looking at snow or
freezing rain, especially in the north and west. By Thursday night
it should be all rain across all but a few southern Indiana
counties. However, confidence in the precip type forecast is
currently too low to add any more value than the mention of rain or
snow, just as a heads-up to the possibility of mixed precip.
Pacific air mass will follow for the end of the week, with dry
weather and seasonable temps.
&&
.Aviation (0Z TAF Issuance)...
Issued at 615 PM EST Sat Feb 16 2013
Sfc high pressure looks to dominate the region for this TAF period
with upper level ridging working eastward into the region through
tomorrow. The only minor TAF concern will be clouds over central IN
that are progged by the NAM and RAP to move south into the SDF/LEX
taf sites tonight. Although most of the cigs up north are currently
at low end VFR levels, short range models suggests these cigs may
lower to between 2-4 kft tonight as they move into our region. The
best time for this to happen looks to be between 1Z-10Z overnight.
Still not confident that the whole cloud deck over central IN won`t
drift farther east and miss the terminals completely and not sure
how solid the deck will be after a portion of it dissipates due to
loss of afternoon instability. Therefore, went with a bkn035 deck
at this time. Will monitor closely this evening and amend if
necessary.
Wind gusts should be declining shortly with a WNW wind expected
overnight probably remaining elevated around 7kts at SDF/LEX.
Expect more westerly winds for tomorrow with wind speeds maxing out
in the 5-7 kt range during the afternoon hours.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......MJP
Long Term........RAS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
403 PM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS EVENING AND BRING SNOW SHOWERS
TO THE AREA. IN THE WAKE OF THE FRONT...COLDER TEMPERATURES WITH
SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD 500MB TROUGH
ACROSS THE MIDWEST WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY
FLOW AHEAD OF THIS FEATURE. 700MB OMEGA INDICATES AN AREA OF LIFT
PUSHING EAST OF THE ALLEGHENY FRONT. THIS LIFT HAS BEEN
RESPONSIBLE FOR GENERALLY 1-2 INCHES OF SNOW ACCUMULATION IN THE
HIGHER ELEVATIONS OF THE ALLEGHENY FRONT. AT THE SURFACE...A COLD
FRONT HAS PUSHED NOW PUSHED EAST OF ZANESVILLE AND IS MOVING
ACROSS EASTERN OHIO. WITH THE FRONT...NUMEROUS SNOW SHOWERS ARE MOVING
ACROSS THE OHIO VALLEY.
THIS EVENING...THE COLD FRONT IS PROGGED TO BE REACH THE PITTSBURGH
METRO BY AROUND 23Z. THE FRONT WILL BRING SNOW SHOWERS...MODERATE
TO HEAVY AT TIMES IN LOCALIZED AREAS. WITH WARMER GROUND AHEAD OF THE
FRONT AND SHOT OF CAA LAGGING SOMEWHAT BEHIND THE FRONT...BELIEVE
THIS WILL LIMIT ACCUMULATION. THUS...WITH THE FRONTAL PASSAGE
ITSELF...SNOW ACCUMULATION WILL MOSTLY BE AN INCH OR LESS ACROSS
THE AREA...NOT OUT OF THE QUESTION A LOCATION COULD GET 2 INCHES
IN MORE LOCALIZED SNOW SHOWERS. HOWEVER...ACCUMULATION WILL MOSTLY
JUST BE ON GRASSY SURFACES AS THE BIGGER IMPACT WITH THE FRONTAL
PASSAGE WILL BE REDUCED VISIBILITIES TO LESS THAN A HALF MILE IN
THE STRONGER SNOW SHOWERS.
TONIGHT...THE FRONT WILL SLIDE EAST OF THE AREA AND CAA WILL
ENSUE. BEHIND THE FRONT...A WESTERLY COMPONENT WILL ALLOW FOR SOME
UPSLOPING ACROSS THE LAUREL HIGHLANDS AND ALLEGHENY FRONT
OVERNIGHT. HOWEVER...DEEP MOISTURE WILL NOT BE PRESENT IN THE WAKE
OF THE FRONT AND THUS ANTICIPATE THAT SNOW WILL BE GENERALLY LIGHT
WITH ADDITIONAL OVERNIGHT ACCUMULATION OF 1 TO 3 INCHES FOR
LOCATIONS ABOVE 2000 FT. ACROSS THE LOWLANDS...AN INVERSION AROUND
4-5KFT WILL LIMIT SNOW SHOWERS AND THUS ANTICIPATE LITTLE OR NO
ACCUMULATION OVERNIGHT. WITH A POST-FRONTAL ARCTIC AIR MASS
SETTLING INTO THE REGION...TEMPS TONIGHT WILL BE NOTICEABLY
COLDER. A MAV/MET BLEND WAS USED WITH LOWS RANGING FROM THE MID
TEENS NORTH AND EAST OF PITTSBURGH TO NEAR 20 IN PORTIONS OF
EASTERN OHIO AND NORTHERN WV.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
A MODEL CONSENSUS INDICATES THAT A MID-LEVEL TROUGH WILL CROSS THE
UPPER OHIO VALLEY SATURDAY INTO SATURDAY NIGHT...PROVIDING FORCING
FOR SCATTERED SNOW SHOWERS BEGINNING IN THE LATE MORNING INTO THE
AFTERNOON ON SATURDAY. WITH THE PASSAGE OF THE TROUGH AROUND AN
INCH OF SNOW IS EXPECTED GENERALLY ACROSS THE AREA...ALTHOUGH
LOCALIZED HIGHER AMOUNTS UP TO THREE INCHES CANNOT BE RULED
OUT...ESPECIALLY WITH UPSLOPING IN THE HIGHER
ELEVATIONS...DEPENDING ON WHERE SCATTERED SNOW SHOWERS DEVELOP.
THE TROUGH WILL SHIFT EAST OF THE AREA ON SUNDAY...WITH SNOW
SHOWERS DIMINISHING IN COVERAGE AND COMING TO AN END FOR MOST OF
THE AREA BY THE AFTERNOON. MODELS REMAIN IN AGREEMENT THAT HIGH
PRESSURE WILL BUILD IN FROM THE SOUTHWEST BEHIND THIS FEATURE AND
ALLOW FOR A DRY FORECAST SUNDAY NIGHT INTO MONDAY.
FOR TEMPS...A NOTICEABLY COLDER WEEKEND IS AHEAD IN CAA BEHIND THE
FRONT. TEMPS WILL STRUGGLE TO REACH 30 ACROSS THE AREA EACH DAY
WITH TEMPS AROUND 10 TO 15 DEGREES BELOW NORMAL. WAA WILL RETURN
AHEAD OF THE FRONT ON MONDAY...ALLOWING FOR TEMPS TO WARM TO A FEW
DEGREES ABOVE SEASONAL NORMS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A STRONG COLD FRONT WILL PUSH ACROSS THE DISTRICT TUESDAY
BRINGING SHOWERS AND WARMER TEMPERATURES AHEAD OF THE FRONT. AS
THE FRONT PUSHES EAST OF THE DISTRICT RAIN SHOWERS WILL CHANGE TO
SNOW SHOWERS AS COLDER TEMPERATURES MOVE IN FOR TUESDAY NIGHT INTO
WEDNESDAY. NORTHWEST FLOW OFF THE LAKES BEHIND THE FRONT WILL
BRING SOME SNOW SHOWERS WEDNESDAY NIGHT. HIGH PRESSURE WILL BRING
DRY WEATHER FOR THURSDAY. ANOTHER COLD FRONT WILL BRING A RISK OF
SHOWERS FOR FRIDAY.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
A COLD FRONT MOVING ACROSS THE DISTRICT THIS EVENING WILL BRING
PERIODS OF SNOW WITH MVFR TO IFR RESTRICTIONS WHEN THE SNOW
IS OCCURRING. GENERAL MVFR OVERCAST CEILINGS CAN BE EXPECTED
TONIGHT WHERE NO SNOW IS FALLING. SNOW IS MOST LIKELY ACROSS THE
SOUTHERN PORTS.
.OUTLOOK.../SATURDAY THROUGH WEDNESDAY/...
PERIODIC RESTRICTIONS ARE POSSIBLE THROUGH SUNDAY AS SEVERAL FAST
MOVING DISTURBANCES MOVE ACROSS THE GREAT LAKES REGION. HIGH
PRESSURE AND VFR CONDITIONS ARE FORECAST TO RETURN MONDAY AND LAST
UNTIL A COLD FRONT APPROACHES TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
SHORT TERM...WOODRUM
LONG TERM...RSD
AVIATION...RSD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1258 PM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA THIS AFTERNOON INTO THE EVENING.
THIS SYSTEM WILL PROVIDE SNOW SHOWERS...WHICH MAY MIX WITH RAIN IN
THE SOUTH. IN THE WAKE OF THE FRONT...COLDER TEMPERATURES WITH
SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO SPEED
UP ONSET OF LIKELY POPS WITH SNOW SHOWERS RELATED TO THE COLD FRONT.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD 500MB TROUGH
ACROSS THE MIDWEST WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY
FLOW AHEAD OF THIS FEATURE. 700MB OMEGA INDICATES AN AREA OF LIFT
ALONG THE OH/WV BORDER THAT IS SHIFTING NORTHEASTWARD INTO NORTH-
CENTRAL WV. THIS LIFT HAS BEEN SUFFICIENT FOR A MIX OF RAIN AND
SNOW SHOWERS MOVING INTO WV. AT THE SURFACE...A COLD FRONT EXTENDS
FROM ONTARIO SOUTHWARD ACROSS CENTRAL OHIO. WITH THE
FRONT...SCATTERED SNOW SHOWERS ARE MOVING ACROSS THE OHIO VALLEY.
TODAY...THE INITIAL AREA OF 700MB OMEGA WILL SLIDE INTO NORTHERN
WV...SOUTHWEST PA...AND WESTERN MD...WITH A STRONG ENOUGH
1000-900MB MELTING LAYER ALLOWING FOR A RAIN/SNOW MIX TO PUSH
INTO THESE AREAS THROUGH THE EARLY AFTERNOON. PRECIPITATION WILL
BE ALL SNOW ACROSS THE ALLEGHENY FRONT AND LAUREL HIGHLANDS AS
ELEVATION NEGATES THE MELTING LAYER. ANY SNOW ACCUMULATION WITH THIS
WILL BE LIMITED TO THE HIGHER ELEVATIONS AND WILL BE GENERALLY
LESS THAN AN INCH. TEMPS TODAY ARE CLOSEST TO LAMP GUIDANCE WITH THE
HRRR TOO WARM. HIGHS WILL RANGE FROM THE MID 30S ALONG THE I-80
AND EASTERN RIDGES TO THE LOWER 40S IN NORTH-CENTRAL WV.
THE COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND IS
PROGGED TO BE BISECTING THE PITTSBURGH METRO BY 00Z. THE FRONT WILL
BRING SNOW SHOWERS TO THE AREA...CHANGING PRECIPITATION TO ALL
SNOW. WITH WARMER GROUND AHEAD OF THE FRONT AND SHOT OF CAA
LAGGING SOMEWHAT BEHIND THE FRONT...BELIEVE THIS WILL LIMIT
ACCUMULATION. THUS...WITH THE FRONTAL PASSAGE ITSELF...SNOW
ACCUMULATION WILL BE AN INCH OR LESS ACROSS THE AREA.
TONIGHT...THE FRONT WILL SLIDE EAST OF THE AREA AND CAA WILL
ENSUE. BEHIND THE FRONT...A WESTERLY COMPONENT WILL ALLOW FOR SOME
UPSLOPING ACROSS THE LAUREL HIGHLANDS AND ALLEGHENY FRONT
OVERNIGHT. HOWEVER...DEEP MOISTURE WILL NOT BE PRESENT IN THE WAKE
OF THE FRONT AND THUS ANTICIPATE THAT SNOW WILL BE GENERALLY LIGHT
WITH ADDITIONAL OVERNIGHT ACCUMULATION OF 1 TO 2 INCHES FOR
LOCATIONS ABOVE 2000 FT. ACROSS THE LOWLANDS...AN INVERSION AROUND
4-5KFT WILL LIMIT SNOW SHOWERS AND THUS ANTICIPATE LITTLE OR NO
ACCUMULATION OVERNIGHT. WITH A POST-FRONTAL ARCTIC AIR MASS
SETTLING INTO THE REGION...TEMPS TONIGHT WILL BE NOTICEABLY
COLDER. A MAV/MET BLEND WAS USED WITH LOWS RANGING FROM THE MID
TEENS NORTH AND EAST OF PITTSBURGH TO NEAR 20 IN PORTIONS OF
EASTERN OHIO AND NORTHERN WV.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SNOW SHOWERS WILL REDEVELOP LATER SATURDAY AND CONTINUE INTO
EARLY SUNDAY AS A TROUGH AXIS...ASSOCIATED WITH UPPER LEVEL LOW
OVER THE NORTHERN GREAT LAKES...SWINGS THROUGH. THIS SYSTEM WILL
ALSO PROVIDE ANOTHER REINFORCING SHOT OF COLD AIR.
SNOW SHOWERS WILL DIMINISH ON SUNDAY AS WINDS BACK TO THE WEST AND
SFC HIGH MOVES THROUGH THE MID-ATLANTIC.
TEMPS THROUGH THE WEEKEND WILL BE BELOW NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE WILL BRING DRY WEATHER AND SEASONABLE TEMPERATURES FOR
SUNDAY NIGHT INTO MONDAY NIGHT. A STRONG COLD FRONT WILL PUSH ACROSS
THE DISTRICT TUESDAY BRINGING SHOWERS AND WARMER TEMPERATURES AHEAD
OF THE FRONT. AS THE FRONT PUSHES EAST OF THE DISTRICT RAIN SHOWERS
WILL CHANGE TO SNOW SHOWERS AS COLDER TEMPERATURES MOVE IN FOR
TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN OF
DRY WEATHER FOR WEDNESDAY NIGHT INTO THURSDAY.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
SCATTERED SHOWERS ARE EXPECTED WITH AN UPPER WAVE THIS AFTERNOON.
THE NORTHERN EXTENT OF RESTRICTIONS IN SNOW IS STILL UP FOR DEBATE
BUT MOST LIKELY AT KMGW. THE SNOW COULD REACH AS FAR NORTH AS KPIT
AND KHLG. VFR CEILINGS WILL PREVAIL AT MOST PORTS THIS AFTERNOON WITH
JUST OCCASIONAL MVFR CEILINGS WHERE THE SNOW IS NOT FALLING. SOME
IFR CONDITIONS ARE POSSIBLE WHERE THE SNOW PERSISTS FOR SEVERAL
HOURS.
A STRONGER COLD FRONT SHOULD BRING ANOTHER WIND SHIFT THIS EVENING
ALONG WITH THE POSSIBILITY OF CIGS DROPPING BACK TO MVFR IN MORE
SCATTERED SHOWERS.
.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
PERIODIC RESTRICTIONS ARE POSSIBLE THROUGH SUNDAY AS SEVERAL FAST
MOVING DISTURBANCES MOVE ACROSS THE GREAT LAKES REGION. HIGH
PRESSURE AND VFR CONDITIONS ARE FORECAST TO RETURN MONDAY AND LAST
UNTIL A COLD FRONT APPROACHES TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AVIATION...RSD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1040 AM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA LATE THIS AFTERNOON INTO THE EVENING.
THIS SYSTEM WILL PROVIDE SNOW SHOWERS...WHICH MAY MIX WITH RAIN
IN THE SOUTH. IN THE WAKE OF THE FRONT...COLDER TEMPERATURES WITH
SNOW SHOWERS ARE EXPECTED THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ADJUST
POPS AND WX GRIDS THIS AFTERNOON.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A BROAD 500MB TROUGH
ACROSS THE MIDWEST WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY
FLOW AHEAD OF THIS FEATURE. 700MB OMEGA INDICATES AN AREA OF LIFT
ALONG THE OH/WV BORDER THAT IS SHIFTING NORTHEASTWARD INTO NORTH-
CENTRAL WV. THIS LIFT HAS BEEN SUFFICIENT FOR A MIX OF RAIN AND
SNOW SHOWERS MOVING INTO WV. AT THE SURFACE...A COLD FRONT EXTENDS
FROM ONTARIO SOUTHWARD ACROSS WESTERN OHIO. WITH THE
FRONT...SCATTERED LIGHT SNOW SHOWERS ARE MOVING ACROSS THE OHIO
VALLEY.
TODAY...THE INITIAL AREA OF 700MB OMEGA WILL SLIDE INTO NORTHERN
WV...SOUTHWEST PA...AND WESTERN MD...WITH A STRONG ENOUGH
1000-900MB MELTING LAYER ALLOWING FOR A RAIN/SNOW MIX TO PUSH
INTO THESE AREAS THROUGH THE EARLY AFTERNOON. PRECIPITATION WILL
BE ALL SNOW ACROSS THE ALLEGHENY FRONT AND LAUREL HIGHLANDS AS
ELEVATION NEGATES THE MELTING LAYER. ANY SNOW ACCUMULATION WITH THIS
WILL BE LIMITED TO THE HIGHER ELEVATIONS AND WILL BE GENERALLY
LESS THAN AN INCH. TEMPS TODAY ARE CLOSEST TO LAMP GUIDANCE WITH THE
HRRR TOO WARM. HIGHS WILL RANGE FROM THE MID 30S ALONG THE I-80
AND EASTERN RIDGES TO THE LOWER 40S IN NORTH-CENTRAL WV.
THE COLD FRONT WILL APPROACH FROM THE WEST THIS AFTERNOON AND IS
PROGGED TO BE BISECTING THE PITTSBURGH METRO AT 00Z. THE FRONT
WILL BRING SNOW SHOWERS TO THE AREA...CHANGING PRECIPITATION TO
ALL SNOW. WITH WARMER GROUND AHEAD OF THE FRONT AND SHOT OF CAA
LAGGING SOMEWHAT BEHIND THE FRONT...BELIEVE THIS WILL LIMIT
ACCUMULATION. THUS...WITH THE FRONTAL PASSAGE ITSELF...SNOW
ACCUMULATION WILL BE AN INCH OR LESS ACROSS THE AREA.
TONIGHT...THE FRONT WILL SLIDE EAST OF THE AREA AND CAA WILL
ENSUE. BEHIND THE FRONT...A WESTERLY COMPONENT WILL ALLOW FOR SOME
UPSLOPING ACROSS THE LAUREL HIGHLANDS AND ALLEGHENY FRONT
OVERNIGHT. HOWEVER...DEEP MOISTURE WILL NOT BE PRESENT IN THE WAKE
OF THE FRONT AND THUS ANTICIPATE THAT SNOW WILL BE GENERALLY LIGHT
WITH ADDITIONAL OVERNIGHT ACCUMULATION OF 1 TO 2 INCHES FOR
LOCATIONS ABOVE 2000 FT. ACROSS THE LOWLANDS...AN INVERSION AROUND
4-5KFT WILL LIMIT SNOW SHOWERS AND THUS ANTICIPATE LITTLE OR NO
ACCUMULATION OVERNIGHT. WITH A POST-FRONTAL ARCTIC AIR MASS
SETTLING INTO THE REGION...TEMPS TONIGHT WILL BE NOTICEABLY
COLDER. A MAV/MET BLEND WAS USED WITH LOWS RANGING FROM THE MID
TEENS NORTH AND EAST OF PITTSBURGH TO NEAR 20 IN PORTIONS OF
EASTERN OHIO AND NORTHERN WV.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
SNOW SHOWERS WILL REDEVELOP LATER SATURDAY AND CONTINUE INTO
EARLY SUNDAY AS A TROUGH AXIS...ASSOCIATED WITH UPPER LEVEL LOW
OVER THE NORTHERN GREAT LAKES...SWINGS THROUGH. THIS SYSTEM WILL
ALSO PROVIDE ANOTHER REINFORCING SHOT OF COLD AIR.
SNOW SHOWERS WILL DIMINISH ON SUNDAY AS WINDS BACK TO THE WEST AND
SFC HIGH MOVES THROUGH THE MID-ATLANTIC.
TEMPS THROUGH THE WEEKEND WILL BE BELOW NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE WILL BRING DRY WEATHER AND SEASONABLE TEMPERATURES FOR
SUNDAY NIGHT INTO MONDAY NIGHT. A STRONG COLD FRONT WILL PUSH ACROSS
THE DISTRICT TUESDAY BRINGING SHOWERS AND WARMER TEMPERATURES AHEAD
OF THE FRONT. AS THE FRONT PUSHES EAST OF THE DISTRICT RAIN SHOWERS
WILL CHANGE TO SNOW SHOWERS AS COLDER TEMPERATURES MOVE IN FOR
TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN OF
DRY WEATHER FOR WEDNESDAY NIGHT INTO THURSDAY.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
SCATTERED SHOWERS ARE EXPECTED WITH AN UPPER WAVE EARLY THIS
AFTERNOON...BUT CONFIDENCE IS ONLY HIGH ENOUGH AT MGW TO INCLUDE
IN TAFS AT THIS TIME. HIGHEST CHANCES FOR PRECIPITATION WILL BE
SOUTH OF PITTSBURGH.
A STRONGER COLD FRONT SHOULD BRING ANOTHER WIND SHIFT THIS EVENING
ALONG WITH THE POSSIBILITY OF CIGS DROPPING BACK TO MVFR IN MORE
SCATTERED SHOWERS.
.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
PERIODIC RESTRICTIONS ARE POSSIBLE THROUGH SUNDAY AS SEVERAL FAST
MOVING DISTURBANCES MOVE ACROSS THE GREAT LAKES REGION. HIGH
PRESSURE AND VFR CONDITIONS ARE FORECAST TO RETURN MONDAY AND LAST
UNTIL A COLD FRONT APPROACHES TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1044 PM EST SAT FEB 16 2013
.UPDATE...
UPDATED TO UPGRADE SANILAC COUNTY TO LAKE EFFECT SNOW WARNING AS
SNOW SHOWERS INDEED CONSOLIDATED INTO AN INTENSE SNOW BAND AROUND
THE PERIPHERY OF NOW WELL DEVELOPED MESO VORTICITY OVER THE
SOUTHERN EDGE OF THE LAKE. CONVECTIVE TOPS CONTINUE TO RUN AT
10KFT WITH 30-35 DBZ RETURNS COMMON ON EXETER WSO RADAR (PUSHING
30 DBZ ON KDTX 88D @ AROUND 8KFT)...SO SUSPECT 2 TO 3 INCH PER
HOUR SNOWFALL RATES IN THE CORE OF THE LARGEST BAND. ORIENTATION
OF THIS BAND AND ANOTHER WEAKER ONE JUST TO ITS NORTH SUGGEST
PARTS OF THE COUNTY WILL RECEIVE 3 TO 4 HOURS WORTH OF AT LEAST 2
INCH PER HOUR SNOW...SO 8+ INCHES WILL BE QUITE POSSIBLE.
&&
.AVIATION...ISSUED 608 PM EST SAT FEB 16 2013
//DISCUSSION...
SCATTERED SNOW SHOWERS WILL GRADUALLY DIMINISH IN INTENSITY AND
COVERAGE THIS EVENING AS SHORTWAVE PIVOTS EAST OF THE AREA. MVFR TO
LOWER VFR CIGS CAN BE EXPECTED WITH THESE SHOWERS WITH OCCASIONAL
VSBYS AOB 2-3SM. MOST ACTIVITY WILL BE OUT OF TERMINALS BY 03Z-04Z
WITH SOME BRIEF CLEARING OVERNIGHT BEFORE DIURNAL STRATO-CU DEVELOPS
BY LATE SUNDAY MORNING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FEET THROUGH 07Z-09Z
TONIGHT.
* HIGH CONFIDENCE IN PRECIPITATION TYPE BEING SNOW.
&&
.PREV DISCUSSION...ISSUED 731 PM EST SAT FEB 16 2013
UPDATE...
WILL MAINTAIN WINTER WEATHER ADVISORY FOR HURON...SANILAC AND ST
CLAIR COUNTIES AS SYNOPTIC SCALE SNOW TRANSITIONS TO SCATTERED TO
NUMEROUS LAKE EFFECT SNOW SHOWERS THIS EVENING AS SHORTWAVE PIVOTS
EAST INTO ONTARIO.
VISIBLE SATELLITE EARLIER DENOTED TWO MAIN MESO-VORTICITY CENTERS
ENHANCING INTENSE SNOW SHOWERS OVER LAKE HURON...ONE 50 KM NORTH
OF GODERICH ONTARIO AND THE OTHER PIVOT SOUTH ONTO THE TIP OF THE
THUMB. HIRES MODELS...3KM HRRR...LOCAL 4KM WRF AND 13KM RUC...HAD
DECENT HANDLE ON EASTERNMOST VORT CENTER...BUT ALL BUT MISSED THE
WESTERNMOST CENTER.
AS THE EVENING HAS PROGRESSED...THIS WESTERN VORTICITY CENTER HAS
TRACKED THROUGH THE THUMB AND BROUGHT ISOLATED INTENSE SNOW
SHOWERS. IT HAS ALSO SEEMED TO ACCELERATE THE SOUTHWARD PIVOT OF
THE OTHER CENTER...AS COMPARED TO THE HIRES MODEL SOLUTIONS WHICH
BROUGHT A GOOD DEAL OF CONVERGENCE ON SHORE...CENTERED ON SANILAC
COUNTY. AS LONG AS THIS TREND CONTINUES (AND THE MOST RECENT 21Z
HRRR RUN SHIFTED THIS DIRECTION)...THE MOST INTENSE AND PERSISTENT
SNOW SQUALLS WILL REMAIN MAINLY OFFSHORE. STILL EXPECT 3 TO 6
INCHES OF SNOW IN LOCAL AREAS NEAR THE LAKE HURON SHORELINE AS
THIS AREA OF SNOW SHOWERS PIVOTS SOUTH AND BRUSHES THE REGION.
IF SECOND MESO VORT IS ABLE TO WOBBLE WESTWARD AT ALL LATER THIS
EVNEING AS IT WORKS IN BEHIND THE FIRST CENTER...A LAKE EFFECT SNOW
WARNING WOULD BE REQUIRED AS ECHO TOPS ON KAPX/KDTX 88DS HAVE BEEN
RUNNING AT 10+ KFT WITH EXETER WSO RADAR SHOWING 30-35 DBZ CORES
IN SIMILAR INTENSE SNOW SHOWERS. THESE TOGETHER SUPPORT 2 TO 3
INCH PER HOUR SNOWFALL RATES IN THE MOST INTENSE SQUALLS SO ANY
BANDING SETTING UP ONSHORE FOR 2 TO 3 HOURS WOULD BRING TOTALS IN
EXCESS OF 6 INCHES.
PREV DISCUSSION...ISSUED 352 PM EST SAT FEB 16 2013
SHORT TERM...THIS AFTERNOON AND TONIGHT
UPPER LEVEL WAVE AND MID LEVEL COLD POOL HAVE BROUGHT SEVERAL SNOW
SQUALLS TO SOUTHEAST MICHIGAN TODAY...DROPPING A QUICK 1 TO 2 INCHES
OF SNOW ACROSS AREAS ALONG AND SOUTH OF THE INTERSTATE 69 CORRIDOR.
HOWEVER THE SURFACE TROUGH AND PV ANOMALY HAVE YET TO TRACK THROUGH
SOUTHEAST MICHIGAN. THESE FEATURES WILL TRACK THROUGH DURING THE
EVENING HOURS AND TURN WINDS TO A NORTHERLY DIRECTION...BRINGING
COOLER AIR AND LAKE MOISTURE IN FROM LAKE HURON. ALTHOUGH THE DTX
HIRES WRF RUNS DEVELOP AN IMPRESSIVE LAKE EFFECT BAND THAT TRACKS
THROUGH THE THUMB REGION BETWEEN 21Z AND 06Z...MODEL INITIALIZATION
IS VERY POOR AS THE 20Z PANEL INDICATES THERE SHOULD BE AN
IMPRESSIVE BAND JUST OFFSHORE OF HURON COUNTY...WHICH BY THE VISIBLE
SATELLITE IMAGERY IS FAR FROM REALITY. THIS FAILURE IN THE MODEL
LOOKS TO BE THE FAILURE OF A MESOLOW TO DEVELOP ACROSS CENTRAL LAKE
HURON...INSTEAD THE LAKE EFFECT IS IN A NORTHWEST TO SOUTHEAST
ORIENTATION BEHIND THE MAIN SURFACE TROUGH. THIS IS ACTUALLY
DEPICTED RATHER WELL BY THE HRRR MODEL WHICH BRINGS THIS FEATURE
SOUTH THROUGH THE EARLY EVENING HOURS AND DEVELOPS A NORTH-SOUTH
BAND OF LAKE EFFECT SNOW ACROSS THE EASTERN THUMB WITH SIGNIFICANT
ASSISTANCE FROM CONVERGENCE AS NORTH-NORTHWEST WINDS OVER THE LAKE
CONVERGE WITH NORTHEASTERLY WINDS ACROSS SOUTHERN LAKE HURON. THIS
SETUP WOULD BRING SEVERAL INCHES OF ACCUMULATING SNOW TO SANILAC AND
ST. CLAIR COUNTIES DURING THE EVENING HOURS UNTIL LAKE WINDS TURN
MORE NORTHERLY AND CONVERGENCE ALONG THE LAKE BECOMES BROADER. TO
ADD TO THE CONFUSION THE NAM MODEL IS VERY BRIEF WITH THE
CONVERGENCE AND KEEPS MOST OF THE LAKE EFFECT SNOW OFFSHORE DURING
THE EVENING HOURS.
GIVEN THE GOOD INITIALIZATION INCLINATION IS TO LEAN TOWARDS THE
HRRR SOLUTION AS EAST-WEST BANDS TEND TO TRANSITION TO NORTH-SOUTH
AS THEY ENCOUNTER THE TOPOGRAPHY OF THE THUMB REGION...HOWEVER
CANNOT RULE OUT THE POSSIBILITY OF A MESOLOW FORMING AND TRACKING
FARTHER INLAND THAN SANILAC AND ST. CLAIR COUNTIES. THEREFORE WILL
HANG ONTO THE WINTER WEATHER ADVISORY FOR THE THUMB REGION AND LET
LATER SHIFTS PARE DOWN THE HEADLINE AS THE NATURE AND ORIENTATION OF
THE LAKE EFFECT BECOME APPARENT DURING THE EVENING HOURS. THE
PREVIOUS FORECAST AMOUNTS STILL LOOK SOLID IN THIS REGION WITH A
GOOD 2 TO 4 INCHES EXPECTED WITH ISOLATED 6 INCH AMOUNTS NEAR THE
LAKE HURON SHORELINE AREAS.
LONG TERM...SUNDAY THROUGH FRIDAY
VERY STRONG NEGATIVE POTENTIAL VORTICITY ADVECTION FROM RETREATING
LARGE WAVELENGTH UPPER LEVEL TROUGH WILL LEAD TO RAPID 1000-500MB
GEOPOTENTIAL HIGH RISES OVER SOUTHEASTERN MICHIGAN 12-00Z SUNDAY.
THE MAXIMUM OF GEOPOTENTIAL HEIGHT RISES WILL REMAIN OVER THE
SOUTHERN APPALACHIANS IN RESPONSE TO THE BOMBING
NOR`EASTER...HOWEVER...HEIGHT RISE RIDGE AXIS WILL EXTEND NORTHWARD
INTO CENTRAL GREAT LAKES. REMNANT LAKE EFFECT WILL BE ONGOING OVER
SOUTH LAKE HURON THROUGH SUNDAY AFTERNOON BEFORE SWEEPING EASTWARD
DUE TO INCREASING WESTERLY COLUMN FLOW. HIGH TEMPERATURES TOMORROW
WILL BE CONSIDERABLY COLD...SOME 10-13 DEGREES BELOW NORMAL. A
RATHER RAW DAY WITH JUST ENOUGH WIND MAGNITUDE TO ALLOW FOR WIND
CHILL VALUES IN THE SINGLE DIGITS BEFORE NOON...TOPPING OUT BETWEEN
10-15 DEGREES FOR THE AFTERNOON. TYPICAL QUESTION MARK EXISTS
CONCERNING POTENTIAL FOR STRATOCUMULUS TOMORROW. THE AREAS
POSITION/PROXIMITY WITHIN EDGE OF RETREATING TROUGH AND OVERALL
ARCTIC AIRMASS SUGGESTS SUNSHINE WILL GREET US IN THE MORNING. THIS
CERTAINLY HAS SUPPORT WHEN LOOKING AT SATELLITE IMAGERY OVER
NORTHERN MINNESOTA. THE MODELED INVERSION AT ROUGHLY 5 KFT AGL IS
INTERESTING AS THE SOLUTION SHOWS NO MOISTURE TRAPPED WITHIN THE
STABLE STRATIFIED LAYER IMMEDIATELY ABOVE INVERSION BASE OR EVEN AT
THE INVERSION BASE ITSELF. WILL CONTINUE WITH THE INHERITED FORECAST
WHICH CALLS FOR SUNSHINE TOMORROW.
MODELS ARE COMING INTO AN AGREEMENT WITH THE SYSTEM THAT WILL
APPROACH THE AREA MONDAY NIGHT. OVERALL...SYSTEM DYNAMICAL SUPPORT
APPEARS ABOVE AVERAGE AS THE SOUTHERN EXTENSION OF THE MIDLEVEL
TROUGH WILL BECOME LINKED TO SOUTHERN STREAM JET STREAM ENERGY OVER
THE FOUR CORNERS AREA SUNDAY NIGHT. THE TROUGH AXIS WHICH WILL BEGIN
AT A POSITIVE TILT WILL TURN NEUTRAL MONDAY NIGHT AND EVENTUALLY
NEGATIVE BY TUESDAY MORNING. THE PRECEDING WARM AIR ADVECTION...WING
OF ISENTROPIC LIFT IS SHOWN TO BE DRY. IT WILL REQUIRE ACTUAL
MOISTURE TRANSPORT AND UPPER LEVEL JET SUPPORT TO GET PRECIPITATION
GOING. DELAYED PRECIPITATION ONSET TIMING A FEW HOURS...NOW EXPECTED
MAINLY FOR THE FIRST HALF OF MONDAY NIGHT. THE GFS SOLUTION AND
RESULTANT PRECIPITATION TYPE SEEMS HIGHLY SUSPECT GIVEN THE OVERALL
HEIGHT PATTERN AND FORECASTED WIND FIELD. REST OF THE MEDIUM RANGE
SUITE SUGGESTS THAT A SUBSTANTIAL WARM LAYER FROM SFC-5 KFT AGL WILL
SLIDE IN SUPPORTING A RAPID TRANSITION TO RAIN. FROM THIS VANTAGE
POINT THIS SYSTEM HAS THE POTENTIAL TO BECOME A HIGHER IMPACT WIND
EVENT. RIGHT NOW...FORECASTED VALUES OF UPWARDS OF 30 KNOTS SEEMS
GOOD...WITH ALL THE MAIN FEATURE SLIGHTLY OUT OF PHASE. SUBSEQUENT
SHIFTS CAN FINE TUNE THIS.
MARINE...
OTHER THAN AN ACTIVE SNOW SHOWER PATTERN TONIGHT...MARINE CONDITIONS
WILL BE FAVORABLE THROUGH SUNDAY IN TERMS OF WIND OVER ALL MARINE
AREAS AND WAVES OVER THE OPEN WATERS OF LAKE HURON. AFTER THAT...A
STRONG LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE PLAINS
AND MIDWEST AND MOVE THROUGH THE GREAT LAKES MONDAY AND TUESDAY.
MILD AIR SPREADING NORTHWARD AHEAD OF THE SYSTEM WILL BRING RAIN TO
ALL AREAS EXCEPT THE FAR NORTH REACHES OF LAKE HURON. A STRONG COLD
FRONT IS EXPECTED TO BRING A SHARP WESTERLY WIND SHIFT TUESDAY
MORNING BUT SPEEDS ARE EXPECTED TO REMAIN BELOW GALE FORCE FOR
NOW. STRONG NORTHWEST WIND TRAILING THE FRONT WILL EASE IN SPEED
DURING WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING...MIZ055...UNTIL 2 AM SUNDAY.
WINTER WEATHER ADVISORY...MIZ049...UNTIL MIDNIGHT SUNDAY.
WINTER WEATHER ADVISORY...MIZ063...UNTIL 2 AM SUNDAY.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......DG
AVIATION.....DG
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
731 PM EST SAT FEB 16 2013
.UPDATE...
WILL MAINTAIN WINTER WEATHER ADVISORY FOR HURON...SANILAC AND ST
CLAIR COUNTIES AS SYNOPTIC SCALE SNOW TRANSITIONS TO SCATTERED TO
NUMEROUS LAKE EFFECT SNOW SHOWERS THIS EVENING AS SHORTWAVE PIVOTS
EAST INTO ONTARIO.
VISIBLE SATELLITE EARLIER DENOTED TWO MAIN MESO-VORTICITY CENTERS
ENHANCING INTENSE SNOW SHOWERS OVER LAKE HURON...ONE 50 KM NORTH
OF GODERICH ONTARIO AND THE OTHER PIVOT SOUTH ONTO THE TIP OF THE
THUMB. HIRES MODELS...3KM HRRR...LOCAL 4KM WRF AND 13KM RUC...HAD
DECENT HANDLE ON EASTERNMOST VORT CENTER...BUT ALL BUT MISSED THE
WESTERNMOST CENTER.
AS THE EVENING HAS PROGRESSED...THIS WESTERN VORTICITY CENTER HAS
TRACKED THROUGH THE THUMB AND BROUGHT ISOLATED INTENSE SNOW
SHOWERS. IT HAS ALSO SEEMED TO ACCELERATE THE SOUTHWARD PIVOT OF
THE OTHER CENTER...AS COMPARED TO THE HIRES MODEL SOLUTIONS WHICH
BROUGHT A GOOD DEAL OF CONVERGENCE ON SHORE...CENTERED ON SANILAC
COUNTY. AS LONG AS THIS TREND CONTINUES (AND THE MOST RECENT 21Z
HRRR RUN SHIFTED THIS DIRECTION)...THE MOST INTENSE AND PERSISTENT
SNOW SQUALLS WILL REMAIN MAINLY OFFSHORE. STILL EXPECT 3 TO 6
INCHES OF SNOW IN LOCAL AREAS NEAR THE LAKE HURON SHORELINE AS
THIS AREA OF SNOW SHOWERS PIVOTS SOUTH AND BRUSHES THE REGION.
IF SECOND MESO VORT IS ABLE TO WOBBLE WESTWARD AT ALL LATER THIS
EVNEING AS IT WORKS IN BEHIND THE FIRST CENTER...A LAKE EFFECT SNOW
WARNING WOULD BE REQUIRED AS ECHO TOPS ON KAPX/KDTX 88DS HAVE BEEN
RUNNING AT 10+ KFT WITH EXETER WSO RADAR SHOWING 30-35 DBZ CORES
IN SIMILAR INTENSE SNOW SHOWERS. THESE TOGETHER SUPPORT 2 TO 3
INCH PER HOUR SNOWFALL RATES IN THE MOST INTENSE SQUALLS SO ANY
BANDING SETTING UP ONSHORE FOR 2 TO 3 HOURS WOULD BRING TOTALS IN
EXCESS OF 6 INCHES.
&&
.AVIATION...ISSUED 608 PM EST SAT FEB 16 2013
//DISCUSSION...
SCATTERED SNOW SHOWERS WILL GRADUALLY DIMINISH IN INTENSITY AND
COVERAGE THIS EVENING AS SHORTWAVE PIVOTS EAST OF THE AREA. MVFR TO
LOWER VFR CIGS CAN BE EXPECTED WITH THESE SHOWERS WITH OCCASIONAL
VSBYS AOB 2-3SM. MOST ACTIVITY WILL BE OUT OF TERMINALS BY 03Z-04Z
WITH SOME BRIEF CLEARING OVERNIGHT BEFORE DIURNAL STRATO-CU DEVELOPS
BY LATE SUNDAY MORNING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FEET THROUGH 07Z-09Z
TONIGHT.
* HIGH CONFIDENCE IN PRECIPITATION TYPE BEING SNOW.
&&
.PREV DISCUSSION...ISSUED 352 PM EST SAT FEB 16 2013
SHORT TERM...THIS AFTERNOON AND TONIGHT
UPPER LEVEL WAVE AND MID LEVEL COLD POOL HAVE BROUGHT SEVERAL SNOW
SQUALLS TO SOUTHEAST MICHIGAN TODAY...DROPPING A QUICK 1 TO 2 INCHES
OF SNOW ACROSS AREAS ALONG AND SOUTH OF THE INTERSTATE 69 CORRIDOR.
HOWEVER THE SURFACE TROUGH AND PV ANOMALY HAVE YET TO TRACK THROUGH
SOUTHEAST MICHIGAN. THESE FEATURES WILL TRACK THROUGH DURING THE
EVENING HOURS AND TURN WINDS TO A NORTHERLY DIRECTION...BRINGING
COOLER AIR AND LAKE MOISTURE IN FROM LAKE HURON. ALTHOUGH THE DTX
HIRES WRF RUNS DEVELOP AN IMPRESSIVE LAKE EFFECT BAND THAT TRACKS
THROUGH THE THUMB REGION BETWEEN 21Z AND 06Z...MODEL INITIALIZATION
IS VERY POOR AS THE 20Z PANEL INDICATES THERE SHOULD BE AN
IMPRESSIVE BAND JUST OFFSHORE OF HURON COUNTY...WHICH BY THE VISIBLE
SATELLITE IMAGERY IS FAR FROM REALITY. THIS FAILURE IN THE MODEL
LOOKS TO BE THE FAILURE OF A MESOLOW TO DEVELOP ACROSS CENTRAL LAKE
HURON...INSTEAD THE LAKE EFFECT IS IN A NORTHWEST TO SOUTHEAST
ORIENTATION BEHIND THE MAIN SURFACE TROUGH. THIS IS ACTUALLY
DEPICTED RATHER WELL BY THE HRRR MODEL WHICH BRINGS THIS FEATURE
SOUTH THROUGH THE EARLY EVENING HOURS AND DEVELOPS A NORTH-SOUTH
BAND OF LAKE EFFECT SNOW ACROSS THE EASTERN THUMB WITH SIGNIFICANT
ASSISTANCE FROM CONVERGENCE AS NORTH-NORTHWEST WINDS OVER THE LAKE
CONVERGE WITH NORTHEASTERLY WINDS ACROSS SOUTHERN LAKE HURON. THIS
SETUP WOULD BRING SEVERAL INCHES OF ACCUMULATING SNOW TO SANILAC AND
ST. CLAIR COUNTIES DURING THE EVENING HOURS UNTIL LAKE WINDS TURN
MORE NORTHERLY AND CONVERGENCE ALONG THE LAKE BECOMES BROADER. TO
ADD TO THE CONFUSION THE NAM MODEL IS VERY BRIEF WITH THE
CONVERGENCE AND KEEPS MOST OF THE LAKE EFFECT SNOW OFFSHORE DURING
THE EVENING HOURS.
GIVEN THE GOOD INITIALIZATION INCLINATION IS TO LEAN TOWARDS THE
HRRR SOLUTION AS EAST-WEST BANDS TEND TO TRANSITION TO NORTH-SOUTH
AS THEY ENCOUNTER THE TOPOGRAPHY OF THE THUMB REGION...HOWEVER
CANNOT RULE OUT THE POSSIBILITY OF A MESOLOW FORMING AND TRACKING
FARTHER INLAND THAN SANILAC AND ST. CLAIR COUNTIES. THEREFORE WILL
HANG ONTO THE WINTER WEATHER ADVISORY FOR THE THUMB REGION AND LET
LATER SHIFTS PARE DOWN THE HEADLINE AS THE NATURE AND ORIENTATION OF
THE LAKE EFFECT BECOME APPARENT DURING THE EVENING HOURS. THE
PREVIOUS FORECAST AMOUNTS STILL LOOK SOLID IN THIS REGION WITH A
GOOD 2 TO 4 INCHES EXPECTED WITH ISOLATED 6 INCH AMOUNTS NEAR THE
LAKE HURON SHORELINE AREAS.
LONG TERM...SUNDAY THROUGH FRIDAY
VERY STRONG NEGATIVE POTENTIAL VORTICITY ADVECTION FROM RETREATING
LARGE WAVELENGTH UPPER LEVEL TROUGH WILL LEAD TO RAPID 1000-500MB
GEOPOTENTIAL HIGH RISES OVER SOUTHEASTERN MICHIGAN 12-00Z SUNDAY.
THE MAXIMUM OF GEOPOTENTIAL HEIGHT RISES WILL REMAIN OVER THE
SOUTHERN APPALACHIANS IN RESPONSE TO THE BOMBING
NOR`EASTER...HOWEVER...HEIGHT RISE RIDGE AXIS WILL EXTEND NORTHWARD
INTO CENTRAL GREAT LAKES. REMNANT LAKE EFFECT WILL BE ONGOING OVER
SOUTH LAKE HURON THROUGH SUNDAY AFTERNOON BEFORE SWEEPING EASTWARD
DUE TO INCREASING WESTERLY COLUMN FLOW. HIGH TEMPERATURES TOMORROW
WILL BE CONSIDERABLY COLD...SOME 10-13 DEGREES BELOW NORMAL. A
RATHER RAW DAY WITH JUST ENOUGH WIND MAGNITUDE TO ALLOW FOR WIND
CHILL VALUES IN THE SINGLE DIGITS BEFORE NOON...TOPPING OUT BETWEEN
10-15 DEGREES FOR THE AFTERNOON. TYPICAL QUESTION MARK EXISTS
CONCERNING POTENTIAL FOR STRATOCUMULUS TOMORROW. THE AREAS
POSITION/PROXIMITY WITHIN EDGE OF RETREATING TROUGH AND OVERALL
ARCTIC AIRMASS SUGGESTS SUNSHINE WILL GREET US IN THE MORNING. THIS
CERTAINLY HAS SUPPORT WHEN LOOKING AT SATELLITE IMAGERY OVER
NORTHERN MINNESOTA. THE MODELED INVERSION AT ROUGHLY 5 KFT AGL IS
INTERESTING AS THE SOLUTION SHOWS NO MOISTURE TRAPPED WITHIN THE
STABLE STRATIFIED LAYER IMMEDIATELY ABOVE INVERSION BASE OR EVEN AT
THE INVERSION BASE ITSELF. WILL CONTINUE WITH THE INHERITED FORECAST
WHICH CALLS FOR SUNSHINE TOMORROW.
MODELS ARE COMING INTO AN AGREEMENT WITH THE SYSTEM THAT WILL
APPROACH THE AREA MONDAY NIGHT. OVERALL...SYSTEM DYNAMICAL SUPPORT
APPEARS ABOVE AVERAGE AS THE SOUTHERN EXTENSION OF THE MIDLEVEL
TROUGH WILL BECOME LINKED TO SOUTHERN STREAM JET STREAM ENERGY OVER
THE FOUR CORNERS AREA SUNDAY NIGHT. THE TROUGH AXIS WHICH WILL BEGIN
AT A POSITIVE TILT WILL TURN NEUTRAL MONDAY NIGHT AND EVENTUALLY
NEGATIVE BY TUESDAY MORNING. THE PRECEDING WARM AIR ADVECTION...WING
OF ISENTROPIC LIFT IS SHOWN TO BE DRY. IT WILL REQUIRE ACTUAL
MOISTURE TRANSPORT AND UPPER LEVEL JET SUPPORT TO GET PRECIPITATION
GOING. DELAYED PRECIPITATION ONSET TIMING A FEW HOURS...NOW EXPECTED
MAINLY FOR THE FIRST HALF OF MONDAY NIGHT. THE GFS SOLUTION AND
RESULTANT PRECIPITATION TYPE SEEMS HIGHLY SUSPECT GIVEN THE OVERALL
HEIGHT PATTERN AND FORECASTED WIND FIELD. REST OF THE MEDIUM RANGE
SUITE SUGGESTS THAT A SUBSTANTIAL WARM LAYER FROM SFC-5 KFT AGL WILL
SLIDE IN SUPPORTING A RAPID TRANSITION TO RAIN. FROM THIS VANTAGE
POINT THIS SYSTEM HAS THE POTENTIAL TO BECOME A HIGHER IMPACT WIND
EVENT. RIGHT NOW...FORECASTED VALUES OF UPWARDS OF 30 KNOTS SEEMS
GOOD...WITH ALL THE MAIN FEATURE SLIGHTLY OUT OF PHASE. SUBSEQUENT
SHIFTS CAN FINE TUNE THIS.
MARINE...
OTHER THAN AN ACTIVE SNOW SHOWER PATTERN TONIGHT...MARINE CONDITIONS
WILL BE FAVORABLE THROUGH SUNDAY IN TERMS OF WIND OVER ALL MARINE
AREAS AND WAVES OVER THE OPEN WATERS OF LAKE HURON. AFTER THAT...A
STRONG LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE PLAINS
AND MIDWEST AND MOVE THROUGH THE GREAT LAKES MONDAY AND TUESDAY.
MILD AIR SPREADING NORTHWARD AHEAD OF THE SYSTEM WILL BRING RAIN TO
ALL AREAS EXCEPT THE FAR NORTH REACHES OF LAKE HURON. A STRONG COLD
FRONT IS EXPECTED TO BRING A SHARP WESTERLY WIND SHIFT TUESDAY
MORNING BUT SPEEDS ARE EXPECTED TO REMAIN BELOW GALE FORCE FOR
NOW. STRONG NORTHWEST WIND TRAILING THE FRONT WILL EASE IN SPEED
DURING WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY...MIZ049...UNTIL MIDNIGHT SUNDAY.
WINTER WEATHER ADVISORY...MIZ055-MIZ063...UNTIL 2 AM SUNDAY.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......DG
AVIATION.....DG
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
608 PM EST SAT FEB 16 2013
.AVIATION...
//DISCUSSION...
SCATTERED SNOW SHOWERS WILL GRADUALLY DIMINISH IN INTENSITY AND
COVERAGE THIS EVENING AS SHORTWAVE PIVOTS EAST OF THE AREA. MVFR TO
LOWER VFR CIGS CAN BE EXPECTED WITH THESE SHOWERS WITH OCCASIONAL
VSBYS AOB 2-3SM. MOST ACTIVITY WILL BE OUT OF TERMINALS BY 03Z-04Z
WITH SOME BRIEF CLEARING OVERNIGHT BEFORE DIURNAL STRATO-CU DEVELOPS
BY LATE SUNDAY MORNING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FEET THROUGH 07Z-09Z
TONIGHT.
* HIGH CONFIDENCE IN PRECIPITATION TYPE BEING SNOW.
&&
.PREV DISCUSSION...ISSUED 352 PM EST SAT FEB 16 2013
SHORT TERM...THIS AFTERNOON AND TONIGHT
UPPER LEVEL WAVE AND MID LEVEL COLD POOL HAVE BROUGHT SEVERAL SNOW
SQUALLS TO SOUTHEAST MICHIGAN TODAY...DROPPING A QUICK 1 TO 2 INCHES
OF SNOW ACROSS AREAS ALONG AND SOUTH OF THE INTERSTATE 69 CORRIDOR.
HOWEVER THE SURFACE TROUGH AND PV ANOMALY HAVE YET TO TRACK THROUGH
SOUTHEAST MICHIGAN. THESE FEATURES WILL TRACK THROUGH DURING THE
EVENING HOURS AND TURN WINDS TO A NORTHERLY DIRECTION...BRINGING
COOLER AIR AND LAKE MOISTURE IN FROM LAKE HURON. ALTHOUGH THE DTX
HIRES WRF RUNS DEVELOP AN IMPRESSIVE LAKE EFFECT BAND THAT TRACKS
THROUGH THE THUMB REGION BETWEEN 21Z AND 06Z...MODEL INITIALIZATION
IS VERY POOR AS THE 20Z PANEL INDICATES THERE SHOULD BE AN
IMPRESSIVE BAND JUST OFFSHORE OF HURON COUNTY...WHICH BY THE VISIBLE
SATELLITE IMAGERY IS FAR FROM REALITY. THIS FAILURE IN THE MODEL
LOOKS TO BE THE FAILURE OF A MESOLOW TO DEVELOP ACROSS CENTRAL LAKE
HURON...INSTEAD THE LAKE EFFECT IS IN A NORTHWEST TO SOUTHEAST
ORIENTATION BEHIND THE MAIN SURFACE TROUGH. THIS IS ACTUALLY
DEPICTED RATHER WELL BY THE HRRR MODEL WHICH BRINGS THIS FEATURE
SOUTH THROUGH THE EARLY EVENING HOURS AND DEVELOPS A NORTH-SOUTH
BAND OF LAKE EFFECT SNOW ACROSS THE EASTERN THUMB WITH SIGNIFICANT
ASSISTANCE FROM CONVERGENCE AS NORTH-NORTHWEST WINDS OVER THE LAKE
CONVERGE WITH NORTHEASTERLY WINDS ACROSS SOUTHERN LAKE HURON. THIS
SETUP WOULD BRING SEVERAL INCHES OF ACCUMULATING SNOW TO SANILAC AND
ST. CLAIR COUNTIES DURING THE EVENING HOURS UNTIL LAKE WINDS TURN
MORE NORTHERLY AND CONVERGENCE ALONG THE LAKE BECOMES BROADER. TO
ADD TO THE CONFUSION THE NAM MODEL IS VERY BRIEF WITH THE
CONVERGENCE AND KEEPS MOST OF THE LAKE EFFECT SNOW OFFSHORE DURING
THE EVENING HOURS.
GIVEN THE GOOD INITIALIZATION INCLINATION IS TO LEAN TOWARDS THE
HRRR SOLUTION AS EAST-WEST BANDS TEND TO TRANSITION TO NORTH-SOUTH
AS THEY ENCOUNTER THE TOPOGRAPHY OF THE THUMB REGION...HOWEVER
CANNOT RULE OUT THE POSSIBILITY OF A MESOLOW FORMING AND TRACKING
FARTHER INLAND THAN SANILAC AND ST. CLAIR COUNTIES. THEREFORE WILL
HANG ONTO THE WINTER WEATHER ADVISORY FOR THE THUMB REGION AND LET
LATER SHIFTS PARE DOWN THE HEADLINE AS THE NATURE AND ORIENTATION OF
THE LAKE EFFECT BECOME APPARENT DURING THE EVENING HOURS. THE
PREVIOUS FORECAST AMOUNTS STILL LOOK SOLID IN THIS REGION WITH A
GOOD 2 TO 4 INCHES EXPECTED WITH ISOLATED 6 INCH AMOUNTS NEAR THE
LAKE HURON SHORELINE AREAS.
LONG TERM...SUNDAY THROUGH FRIDAY
VERY STRONG NEGATIVE POTENTIAL VORTICITY ADVECTION FROM RETREATING
LARGE WAVELENGTH UPPER LEVEL TROUGH WILL LEAD TO RAPID 1000-500MB
GEOPOTENTIAL HIGH RISES OVER SOUTHEASTERN MICHIGAN 12-00Z SUNDAY.
THE MAXIMUM OF GEOPOTENTIAL HEIGHT RISES WILL REMAIN OVER THE
SOUTHERN APPALACHIANS IN RESPONSE TO THE BOMBING
NOR`EASTER...HOWEVER...HEIGHT RISE RIDGE AXIS WILL EXTEND NORTHWARD
INTO CENTRAL GREAT LAKES. REMNANT LAKE EFFECT WILL BE ONGOING OVER
SOUTH LAKE HURON THROUGH SUNDAY AFTERNOON BEFORE SWEEPING EASTWARD
DUE TO INCREASING WESTERLY COLUMN FLOW. HIGH TEMPERATURES TOMORROW
WILL BE CONSIDERABLY COLD...SOME 10-13 DEGREES BELOW NORMAL. A
RATHER RAW DAY WITH JUST ENOUGH WIND MAGNITUDE TO ALLOW FOR WIND
CHILL VALUES IN THE SINGLE DIGITS BEFORE NOON...TOPPING OUT BETWEEN
10-15 DEGREES FOR THE AFTERNOON. TYPICAL QUESTION MARK EXISTS
CONCERNING POTENTIAL FOR STRATOCUMULUS TOMORROW. THE AREAS
POSITION/PROXIMITY WITHIN EDGE OF RETREATING TROUGH AND OVERALL
ARCTIC AIRMASS SUGGESTS SUNSHINE WILL GREET US IN THE MORNING. THIS
CERTAINLY HAS SUPPORT WHEN LOOKING AT SATELLITE IMAGERY OVER
NORTHERN MINNESOTA. THE MODELED INVERSION AT ROUGHLY 5 KFT AGL IS
INTERESTING AS THE SOLUTION SHOWS NO MOISTURE TRAPPED WITHIN THE
STABLE STRATIFIED LAYER IMMEDIATELY ABOVE INVERSION BASE OR EVEN AT
THE INVERSION BASE ITSELF. WILL CONTINUE WITH THE INHERITED FORECAST
WHICH CALLS FOR SUNSHINE TOMORROW.
MODELS ARE COMING INTO AN AGREEMENT WITH THE SYSTEM THAT WILL
APPROACH THE AREA MONDAY NIGHT. OVERALL...SYSTEM DYNAMICAL SUPPORT
APPEARS ABOVE AVERAGE AS THE SOUTHERN EXTENSION OF THE MIDLEVEL
TROUGH WILL BECOME LINKED TO SOUTHERN STREAM JET STREAM ENERGY OVER
THE FOUR CORNERS AREA SUNDAY NIGHT. THE TROUGH AXIS WHICH WILL BEGIN
AT A POSITIVE TILT WILL TURN NEUTRAL MONDAY NIGHT AND EVENTUALLY
NEGATIVE BY TUESDAY MORNING. THE PRECEDING WARM AIR ADVECTION...WING
OF ISENTROPIC LIFT IS SHOWN TO BE DRY. IT WILL REQUIRE ACTUAL
MOISTURE TRANSPORT AND UPPER LEVEL JET SUPPORT TO GET PRECIPITATION
GOING. DELAYED PRECIPITATION ONSET TIMING A FEW HOURS...NOW EXPECTED
MAINLY FOR THE FIRST HALF OF MONDAY NIGHT. THE GFS SOLUTION AND
RESULTANT PRECIPITATION TYPE SEEMS HIGHLY SUSPECT GIVEN THE OVERALL
HEIGHT PATTERN AND FORECASTED WIND FIELD. REST OF THE MEDIUM RANGE
SUITE SUGGESTS THAT A SUBSTANTIAL WARM LAYER FROM SFC-5 KFT AGL WILL
SLIDE IN SUPPORTING A RAPID TRANSITION TO RAIN. FROM THIS VANTAGE
POINT THIS SYSTEM HAS THE POTENTIAL TO BECOME A HIGHER IMPACT WIND
EVENT. RIGHT NOW...FORECASTED VALUES OF UPWARDS OF 30 KNOTS SEEMS
GOOD...WITH ALL THE MAIN FEATURE SLIGHTLY OUT OF PHASE. SUBSEQUENT
SHIFTS CAN FINE TUNE THIS.
MARINE...
OTHER THAN AN ACTIVE SNOW SHOWER PATTERN TONIGHT...MARINE CONDITIONS
WILL BE FAVORABLE THROUGH SUNDAY IN TERMS OF WIND OVER ALL MARINE
AREAS AND WAVES OVER THE OPEN WATERS OF LAKE HURON. AFTER THAT...A
STRONG LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE PLAINS
AND MIDWEST AND MOVE THROUGH THE GREAT LAKES MONDAY AND TUESDAY.
MILD AIR SPREADING NORTHWARD AHEAD OF THE SYSTEM WILL BRING RAIN TO
ALL AREAS EXCEPT THE FAR NORTH REACHES OF LAKE HURON. A STRONG COLD
FRONT IS EXPECTED TO BRING A SHARP WESTERLY WIND SHIFT TUESDAY
MORNING BUT SPEEDS ARE EXPECTED TO REMAIN BELOW GALE FORCE FOR
NOW. STRONG NORTHWEST WIND TRAILING THE FRONT WILL EASE IN SPEED
DURING WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY...MIZ049-MIZ054-MIZ062...UNTIL 10 PM
SATURDAY.
WINTER WEATHER ADVISORY...MIZ055-MIZ063...UNTIL 2 AM SUNDAY.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
113 PM EST FRI FEB 15 2013
.SYNOPSIS...
ISSUED AT 1053 AM EST FRI FEB 15 2013
SNOW WILL INTENSIFY THIS EVENING AND LINGER THROUGH SATURDAY
EVENING. THIS WILL BRING SIX TO NINE INCHES OF SNOW TO THE
LAKESHORE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THIS GREATEST
SNOWFALL AMOUNTS ARE EXPECTED MAINLY ALONG THE LAKESHORE COUNTIES.
FARTHER INLAND CLOSER TO THE US-131 CORRIDOR...TOTALS OF 2 TO 5
INCHES WILL BE MORE COMMON...WITH EVEN LESSER AMOUNTS FARTHER
EAST.
THE SNOW WILL DIMINISH INTO SATURDAY NIGHT WITH SOME SUNSHINE
EXPECTED BY SUNDAY. THEN ANOTHER PERIOD OF SNOW IS EXPECTED FOR
MONDAY AND MONDAY NIGHT. WITH MORE SNOW POSSIBLE AGAIN BY THE END
OF THE WORK WEEK.
&&
.UPDATE...
ISSUED AT 1053 AM EST FRI FEB 15 2013
TRIMMED BACK SNOW ACCUMULATIONS TODAY BASED ON LATEST OBSERVATIONS
AND MODEL GUIDANCE. LATEST RUNS OF THE RAP MODEL SUGGEST ACCUMULATING
SNOW WILL BE DELAYED UNTIL AFTER 6 TO 7 PM TONIGHT. ALSO LOWERED
INLAND SNOW AMOUNTS OVERALL AS WE EXPECT A FAIRLY SHARP DROP OFF
IN ACCUMULATIONS AWAY FROM THE LAKE SHORE BASED ON THE REASONING
IN THE PREVIOUS DISCUSSION REGARDING CROSS HAIR SIGNATURE
PLACEMENT AND LIKELY INLAND CELLULAR NATURE OF PRECIPITATION
SATURDAY. WILL BE ISSUING AN ADVISORY UPDATE SHORTLY TO REFLECT
THIS CHANGE IN THINKING.
WE ARE LOOKING AT THE POTENTIAL FOR SIGNIFICANT SNOWFALL ENHANCEMENT
ACROSS OUR NORTHERN ZONES AFTER MIDNIGHT AS THE NAM SUGGESTS A
MESOLOW WILL ZIP SOUTHEAST THROUGH LUDINGTON. THIS WILL BE
SOMETHING TO WATCH FOR THE AFTERNOON UPDATE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 342 AM EST FRI FEB 15 2013
HAVE DECIDED TO GO WITH A LAKE EFFECT SNOW ADVISORY FOR ROUGHLY THE
WESTERN HALF OF THE CWA STARTING LATE THIS AFTERNOON AND CONTINUING
INTO SATURDAY EVENING.
LONG DURATION LAKE EFFECT EVENT WILL RAMP UP LATE THIS AFTERNOON A
STRONG WAVE ENERGY PIVOTS IN. INVERSION HEIGHTS WILL CLIMB LEADING
TO AN INCREASED INTENSITY TO THE THE SNOW SHOWERS. FAVORABLE OMEGA
CROSS HAIR SIGNATURE WITHIN THE DGZ LINES UP ALONG THE LAKE SHORE
COUNTIES BY THIS EVENING AND REMAINS PERSISTENT RIGHT INTO SATURDAY
EVENING. MEAN FLOW WILL WAVER SOMEWHAT...SO NOT SURE HOW PERSISTENT
THE SNOW WILL BE AT ANY ONE SPOT...HENCE THE ADVISORY VERSUS A
WARNING. THE FLOW WILL BE 290-300 MUCH OF TONIGHT...BUT THEN IT
BECOMES 310-340 FOR SATURDAY/SATURDAY EVENING WHICH WILL SHIFT THE
SNOW BANDS A BIT.
ANOTHER CONSIDERATION WILL BE THE IMPACT OF THE HIGHER SUN ANGLE
THIS TIME OF YEAR. WE ARE GETTING INTO THAT TIME OF YEAR WHERE THE
LAKE EFFECT CAN BECOME MORE CELLULAR DUE TO DAYTIME CONVECTIVE
ELEMENTS. THIS COULD ALSO LOWER ACCUMS A BIT...OR AT LEAST AFFECT A
PERSISTENT DAYTIME HEAVY SNOW BAND.
ALL IN ALL...EXPECT SOME AREAS ALONG THE LAKE SHORE COUNTIES MAY SEE
UP TO NINE INCHES OF SNOW OVER THE 30 HOUR HEADLINE PERIOD. AMOUNTS
WILL LOWER FURTHER INLAND...BUT THE U.S. 131 COUNTIES WILL STILL SEE
A PERSISTENT SNOW WITH 4 TO 8 INCHES POSSIBLE THERE. EASTERN
COUNTIES WILL SEE SNOW TOO DUE THE SYNOPTIC SHORT WAVE AND SOME LAKE
ENHANCEMENT. FEEL A 2 TO 4 INCH ACCUM SHOULD OCCUR OVER THE SAME
30 HOUR PERIOD.
OTHERWISE...UNTIL WE SEE THE RAMP UP LATE THIS AFTERNOON...THE SNOW
SHOWERS WILL CONTINUE ON A LIGHTER RATE. INVERSION LEVELS STAY
AROUND 5K FEET UNTIL THE SHORT WAVE ARRIVES.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 342 AM EST FRI FEB 15 2013
TWO STORMS ARE EXPECTED NEXT WEEK AND THE SECOND ONE COULD BE MAJOR.
FIRST UP...A CLIPPER MOVES TOWARDS LOWER MICHIGAN ON MONDAY WHILE
PHASING WITH A SOUTHERN STREAM LOW RIGHT OVER LOWER MICHIGAN.
FORECAST CONFIDENCE IS HIGH IN THAT THE MODELS HAVE AGREED ON A RAIN
AND SNOW MIX MOVING IN LATE MONDAY...CHANGING TO SNOW MONDAY NIGHT.
THIS IS FOLLOWED BY WEST FLOW LAKE EFFECT SNOW FROM TUESDAY
AFTERNOON INTO WEDNESDAY.
SFC AND SHORTWAVE UPPER RIDGING MOVES IN TO END THE LAKE EFFECT ON
WEDNESDAY NIGHT...BUT THE LULL WILL BE SHORT LIVED AS A STORM
APPEARS TO BE TAKING SHAPE ACROSS THE PLAINS. THE GULF IS WIDE OPEN
FOR THIS ONE AND A COLD SFC HIGH IS IN PLACE ACROSS EASTERN CANADA.
MODELS HAVE SHOWN THIS STORM FOR A COUPLE DAYS NOW WITH PRETTY GOOD
CONSISTENCY. THURSDAY COULD SEE THE ONSET OF THE STORM WITH SNOW
BREAKING OUT LATE IN THE AFTERNOON...ALTHOUGH BOTH THE GFS AND ECMWF
SHOW THE HEAVIER SNOW NOT ARRIVING UNTIL THURSDAY NIGHT OR FRIDAY.
EVEN AT THIS LONG RANGE THE MODELS ARE SHOWING STRONG F-GEN
POTENTIAL SO THIS COULD BE THE BIGGEST SYNOPTIC SNOW EVENT OF THE
WINTER SO FAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 113 PM EST FRI FEB 15 2013
MAIN FOCUS OF THE 18Z FCSTS IS LAKE EFFECT TRENDS THROUGH THE
PERIOD. LIGHT LAKE EFFECT IS CURRENTLY OCCURRING ACROSS THE AREA
THIS AFTERNOON. OBVIOUSLY THE BEST CONCENTRATION IS CLOSER TO THE
LAKESHORE SOUTH OF KMKG AND WEST OF KGRR. NOT A LOT OF MESOSCALE SUPPORT
THIS AFTERNOON FOR LAKE EFFECT...WHICH IS LEADING TO CONDITIONS
REMAINING MVFR OR BETTER. WE EXPECT THAT THE LAKE EFFECT WILL
INTENSIFY LATER THIS EVENING AND ESPECIALLY OVERNIGHT...ESPECIALLY
AT THE FOUR MOST WRN TERMINALS. IFR WILL BECOME LIKELY AS
CONDITIONS BECOME MORE FAVORABLE FOR LAKE EFFECT. KLAN AND KJXN
WILL SEE LESS IN THE WAY OF IMPACT.
LAKE EFFECT SHOULD DIMINISH INLAND MID MORNING ON SAT AS THE FLOW
BECOMES MORE NW AS A LOW PUSHES AWAY FROM THE AREA. KAZO WILL BE
THE MOST IMPACTED TERMINAL WITH CONTINUED POSSIBLE IFR WITH THE NW
FLOW.
&&
.MARINE...
ISSUED AT 1053 EST FRI FEB 15 2013
KEPT THE SMALL CRAFT ADVISORY INTACT...BUT THERE ARE INDICATIONS
WE WILL STAY BELOW THRESHOLDS AFTER THIS EVENING. WE ARE CONSIDERING
SCALING BACK THE DURATION OF THE SCA FOR THE AFTERNOON UPDATE.
&&
.HYDROLOGY...
ISSUED AT 342 AM EST FRI FEB 15 2013
ONLY ONE FLOOD ADVISORY REMAINS ON THE PERE MARQUETTE AT
SCOTTVILLE. THIS IS EXPECTED TO REMAIN FAIRLY STEADY OVER THE SHORT
TERM. OTHERWISE WITH THE POLAR AIR COMING IN ANY MELT OFF HAS ENDED
THROUGH AT LEAST THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 PM EST SATURDAY FOR MIZ037-
043-050-056-064-071-072.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SATURDAY FOR MIZ038-044-057-065-073.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...TJT
SYNOPSIS...TJT
SHORT TERM...JK
LONG TERM...OSTUNO
AVIATION...NJJ
HYDROLOGY...JK
MARINE...TJT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1231 PM EST FRI FEB 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EST FRI FEB 15 2013
THE LOW THAT AFFECTED THE SOUTHERN PART OF THE CWA YESTERDAY MORNING
HAS LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. RUC ANALYZED
850MB TEMPS ARE AROUND -16C OVER LAKE SUPERIOR AND NORTH-NORTHWEST
WINDS ALOFT HAS LED TO LAKE EFFECT SNOW OVER PORTIONS OF LAKE
SUPERIOR EARLY THIS MORNING. THE BEST SNOW HAS BEEN OCCURRING OVER
IN THE MULTI-BANDED SNOW OVER EASTERN LAKE SUPERIOR...WHERE
INVERSION HEIGHTS ARE AROUND 8KFT BASED OF KMQT RADAR AND THERE IS
ENOUGH MOISTURE PRESENT. FARTHER WEST...DRIER AIR THIS EVENING HAS
LIMITED MUCH OF THE LAKE EFFECT SNOW THUS FAR. BUT WITH A SHORTWAVE
JUST NORTHWEST OF LAKE SUPERIOR EXPECTED TO INCREASE MOISTURE ACROSS
THE AREA...HAVE SEEN A SLIGHT INCREASE IN COVERAGE ON SATELLITE
BETWEEN THE HIGHER CLOUDS. THIS WILL ALSO INCREASE THE INVERSION
HEIGHTS FROM 3-4KFT TO 6-8KFT OVER THE WEST. THUS...EXPECT THE LAKE
EFFECT TO TO CONTINUE TO INCREASE IN INTENSITY/COVERAGE FOR BOTH
WEST/EAST THROUGH THE MORNING HOURS FOR LOCATIONS FAVORED BY
NORTH-NORTHWEST WINDS. WITH MUCH OF THE CONVECTIVE PORTION OF THE
CLOUD WITHIN THE DGZ...EXPECT VERY FLUFFY LAKE EFFECT AND SNOW
RATIOS IN THE 30-1 RANGE. THIS WILL ALLOW FOR QUICK ACCUMULATIONS IN
THE STRONGER BANDS...ESPECIALLY SINCE WINDS WILL HAVE DECREASED FROM
THE 20-30KTS SEEN AROUND MIDNIGHT. ONE ITEM OF CONCERN FOR THE
INTENSITY THIS MORNING OVER THE WEST...ESPECIALLY OVER THE
KEWEENAW...IS THE 30 DEGREES OF SHEAR BETWEEN THE TOP OF THE
INVERSION /800MB/ AND THE MIDDLE OF THE CONVECTIVE CLOUD /900MB/.
THIS MAY LIMIT THE DEEP AND ORGANIZED BANDS THAT WOULD PROMOTE VERY
HEAVY SNOW.
AS THIS SHORTWAVE DEPARTS LATE THIS MORNING AND INTO THE
AFTERNOON...WOULD THINK THE LAKE EFFECT WILL DIMINISH SOME AS
DIURNAL MIXING HELPS REDUCE THE INTENSITY OF THE BANDS OVER THE
WEST. IN ADDITION...THE DEEPER MOISTURE SLIDES MORE OVER THE EASTERN
LAKE WHILE WINDS BACK TO THE NORTHWEST. THIS WILL HELP REDUCE THE
INTENSITY OF THE BANDS SLIGHTLY...BUT THE BACKING WINDS WILL CAUSE
THE HEAVIEST SNOW TO SHIFT FROM THE MORE NNW FAVORED AREAS TO NW
AREAS. ALTHOUGH THIS WILL SPREAD THE LAKE EFFECT TO MORE AREAS...IT
MIGHT CAUSE SOME LIMITATION IN THE HIGHER SNOWFALL AMOUNTS IN ONE
LOCATION TO BE PRIMARILY IN THE ADVISORY CRITERIA CATEGORY. HIGHER
RESOLUTION MODELS DO PICK UP ON BOTH OF THESE FEATURES WELL AND
WILL FOLLOW THEIR TIMING FOR THE MOVEMENT AND INTENSITY FOR THIS
AFTERNOON. OVER THE EAST...INVERSION HEIGHTS OVER THE EAST RISE TO
8-10KFT THIS AFTERNOON AND CONTINUE INTO THE EVENING. WITH THE
DEEPER MOISTURE FROM THE SHORTWAVE AND SOME ENHANCED CONVERGENCE ON
THE SOUTHWEST EDGE OF THE LAKE EFFECT...EXPECT A FAIRLY HEAVY BAND
OR TWO WITHIN THE MULTI-BAND SNOW TO SETUP SOMEWHERE BETWEEN
MUNISING AND GRAND MARAIS. THIS NW WIND WILL ALSO LEAD TO
AN INCREASED PERIOD OF SNOW FOR NORTHERN LUCE COUNTY LATER THIS
AFTERNOON AND INTO THE EARLY EVENING. THIS IS DUE TO THE LONGER
FETCH THAN THEY WILL SEE FOR THE FIRST PART OF TODAY WITH THE
NORTHERLY WINDS. THERE IS THE POTENTIAL FOR SOME HEAVIER SNOWFALL
RATES AND ADVISORY SNOWFALL DURING THAT PERIOD...SO FELT
COMFORTABLE ISSUING AN ADVISORY EVEN THOUGH THERE IS SOME CONCERN
ON THE TIMING OF WHEN THE BAND WILL BACK TO THE WEST TONIGHT AS
WINDS SHIFT TO THE NORTHEAST.
COLDER AIR ARRIVES TONIGHT...WITH 850MB TEMPS FALLING TOWARDS -22C
OVER THE WEST AND -20C OVER THE EAST. OVER THE WEST...THE PRODUCES
SOME CONCERN AS IT WILL PUT A PORTION OF THE CONVECTIVE CLOUD LAYER
AT THE TOP OF OR ABOVE THE DGZ AND LIKELY REDUCE THE SNOW RATIOS
SOMEWHAT. BUT INCREASED CONVERGENCE AS WINDS VEER TO A MORE
NORTHERLY DIRECTION DURING THE EVENING...DUE TO THE APPROACHING HIGH
IN THE NORTHERN PLAINS...WILL HELP INCREASE THE
INTENSITY OF THE SNOW BEFORE RETURNING TO MORE OF A GENERAL
MULTI-BAND LAKE EFFECT DURING THE OVERNIGHT HOURS. ALSO...ANOTHER
WEAK SHORTWAVE IN THE UPPER TROUGH WILL HELP INCREASE MOISTURE AND
KEEP INVERSION HEIGHTS IN THE 7-8KFT RANGE.
OVER THE EAST...THERE DOES SEEM TO BE A SLIGHT SLOWDOWN TO THE
WESTWARD TRANSITION OF THE LAKE EFFECT FROM THE NORTHWEST FAVORED
AREAS TO MORE NORTHERLY COMPARED TO 24HRS AGO...AS THE SURFACE
TROUGH OVER EASTERN LAKE SUPERIOR WEAKENS AND LAND BREEZE INFLUENCES
OFF ONTARIO TAKE OVER. SOME OF THE HIGHER RESOLUTION MODEL RUNS EVEN
TRY TO DEVELOP A WEAK MESO-LOW...WHICH WOULD COMPLICATE MATTERS
FURTHER. THUS...HAVE SLOWED THE WESTWARD TRANSITION A TOUCH AS THE
STRONGER BANDS MAKE THE WESTWARD TRACK ACROSS ALGER AND NORTHERN
SCHOOLCRAFT COUNTIES DURING THE NIGHT. THE INCREASED CONVERGENCE
WITHIN THIS BAND SHOULD LEAD TO SOME HEAVY SNOWFALL RATES AS IT
TRANSITIONS TO THE WEST.
ALL IN ALL...WILL LEAVE THE WARNING HEADLINES AS IS AND ADD
THE LUCE ADVISORY. THERE IS SOME SLIGHT CONCERN ON GETTING WARNING
AMOUNTS IN A WIDESPREAD AREA OF GOGEBIC/ONTONAGON
COUNTIES...BUT SHOULD EASILY SEE THE 12 INCHES IN 24HRS OVER
THE PORKIES. THE ONE QUESTION TO CARRY FORWARD TO THE DAY SHIFT IS
THE BORDERLINE ADVISORY SNOW FOR NORTHERN HOUGHTON AND KEWEENAW
COUNTIES. DIDN/T HAVE A GOOD FEELING ON ADVISORY AMOUNTS FOR
TODAY...ALTHOUGH WITH THE FLUFFY NATURE...COULD SEE A QUICK 4 INCHES
IN A LOCATION IF A BAND SETS UP FOR A FEW HOURS THIS MORNING. IN
ADDITION...WITH THE WINDS BACKING TO THE NW THIS AFTERNOON AND THEN
MORE OUT OF THE NORTH TONIGHT...WOULDN/T THINK THEY WOULD SEE A
PERSISTENT AREA OF TO RAISE CONFIDENCE ENOUGH FOR AN ADVISORY AT
THIS TIME. WITH THE MORE FAVORABLE MOISTURE TONIGHT AND SOME
ENHANCED CONVERGENCE...WOULD THINK THE BEST POTENTIAL FOR ADVISORY
SNOW WOULD BE OVER NORTHERN HOUGHTON COUNTY TOWARDS TWIN LAKES AND
THE DAY SHIFT MAY NEED TO SEE IF THAT IDEA CONTINUES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EST FRI FEB 15 2013
SATURDAY...HIGHER RES MODELS SUGGEST THAT LAKE INDUCED TROUGHING WILL
FOCUS STRONGEST LOW LEVEL CONV AND LES INTO NORTH CENTRAL UPPER MI
BTWN MARQUETTE AND MUNISING. CONTINUED HIGH SLR NEAR 30/1 WOULD
SUPPORT SOME SNOW TOTALS IN THE 4 TO 7 INCH RANGE. CONFIDENCE IN THE
LOCATION OF THIS MESO SCALE FEATURE IS LIMITED BUT A HEADLINE FOR THE FAR
EASTERN PORTION OF MARQUETTE COUNTY MAY BE NECESSARY IF MODEL
AGREEMENT IS CONSISTENT. OVER THE WEST...LES WILL DIMINISH MORE
QUICKLY WITH THE SFC RIDGE AND DRIER AIR BUILDING INTO THE AREA
LEADING TO ADDITIONAL TOTALS ONLY IN THE 1 TO 4 INCH RANGE. A SHALLOW
DGZ WITH LESS FAVORABLE SLR WOULD ALSO LIMIT ACCUMULATION POTENTIAL.
SAT NIGHT...ALTHOUGH LES WILL CONTINUE TO DIMINISH WITH THE RIDGE
BUILDING INTO THE AREA...LIGHT WIND FIELDS AND CONTINUED LOW LEVEL
CONV...ESPECIALLY NEAR THE SHORELINE VCNTY KP53 COULD PRODUCE
SEVERAL ADDITIONAL INCHES OF SNOW. OTHERWISE...CLEARING WITH
FAVORABLE RADIATIONAL COOLING CONDITIONS WILL SUPPORT MIN TEMPS NEAR
THE LOWER END OF GUIDANCE...INTO THE -15F TO -20F RANGE INTERIOR
WEST HALF.
SUN AND SUN NIGHT...A PROGRESSIVE PATTERN WITH THE SFC RIDGE
SHIFTING TO THE EAST...A TROUGH INTO THE NRN PLAINS TO THE UPPER MS
VALLEY AND A STRENGTHENING WAA PATTERN WILL ALLOW MOISTURE TO
INCREASE. BOTH THE GFS AND ECMWF SUGGEST THE STRONGEST ISENTROPIC
LIFT WILL REMAIN NORTH OF THE CWA WITH ONLY CHANCE POPS FOR LIGHT
SNOW BY LATE SUN NIGHT.
MON INTO MON NIGHT...MODELS WERE SIMILAR WITH A MID/UPPER LEVEL
TROUGH INTO THE WRN GREAT LAKES. THE ECMWF WAS A BIT SLOWER AND MORE
AGGRESSIVE IN DIGGING THE TROUGH AND SFC LOW TO THE SOUTH COMPARED
TO THE GFS...BUT NOT AS MUCH AS THE CMC...RESULTING IN GREATER PCPN
ACROSS UPPER MICHIGAN. WITH SUFFICIENT MOISTURE INFLOW BRINGING PWAT
TO NEAR 200 PCT NORMAL THE POTENTIAL REMAINS FOR MODERATE SNOW
ACCUMULATIONS WITH THE SYSTEM.
TUE-WED...SIGNFICANT/HEAVY LES WILL BE POSSIBLE IN THE WAKE OF THE
LOW WITH STRONG CAA DROPPING 850 MB TEMPS INTO THE -15C TO -20C
RANGE ALONG WITH CYCLONIC NNW FLOW AND ABUNDANT 850-700
MOISTURE...PER ECMWF. LES SHOULD DIMINISH WED AS RIDGING AGAIN
BUILDS INTO THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1227 PM EST FRI FEB 15 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE AT ALL SITES. EXPECT THE
STRONGEST SNOW THROUGH MUCH OF THE DAYTIME HOURS AT KIWD WITH THE
MORE FAVORABLE AND CONVERGENT FLOW EARLY THIS AFTERNOON. BUT AS
WINDS BACK MORE TO THE NORTHWEST...EXPECT CONDITIONS TO BECOME LESS
FAVORABLE AT KIWD. EXPECT PERIODS OF ALTERNATE LANDING MINIMUMS
VISIBILITIES TONIGHT AS LOW LEVEL CONVERGENCE INCREASES WITH WINDS
VEERING TO THE NNW...INCREASING THE INTENSITY OF THE SNOW.
AT KSAW...UNFAVORABLE DOWNSLOPING NW FLOW WILL GENERALLY KEEP
BORDERLINE MVFR/VFR CEILINGS THROUGH THE PERIOD WITH OCCASIONAL
SNOW SHOWERS FROM ENHANCED SNOW OFF THE HURON MOUNTAINS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST FRI FEB 15 2013
NORTHWEST WINDS OF 20-30KTS WILL DIMINISH TODAY AS HIGH PRESSURE IN
THE NORTHERN PLAINS SLOWLY SHIFTS EAST INTO THE UPPER GREAT LAKES.
THIS WILL CONTINUE TO DIMINISH THE WINDS ON THROUGH SATURDAY.
BEFORE THE WINDS DIMINISH...HEAVY FREEZING SPRAY IS EXPECTED OVER
PORTIONS OF LAKE SUPERIOR THROUGH TONIGHT. AS THE HIGH SHIFTS EAST
ON SUNDAY A LOW PRESSURE SYSTEM WILL APPROACH THE UPPER GREAT LAKES
ON MONDAY AND MOVE THROUGH ON TUESDAY. THIS WILL BRING INCREASING
SOUTHERLY FLOW ON MONDAY...TO 25KTS OVER THE EAST...AND THEN STRONG
NORTHERLY WINDS BEHIND THE LOW ON TUESDAY AFTERNOON...TO 30KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST SATURDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST SATURDAY FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ SATURDAY FOR
MIZ002-009.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST SATURDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...TITUS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1054 AM EST FRI FEB 15 2013
.SYNOPSIS...
ISSUED AT 1053 EST FRI FEB 15 2013
SNOW WILL INTENSIFY THIS EVENING AND LINGER THROUGH SATURDAY
EVENING. THIS WILL BRING SIX TO NINE INCHES OF SNOW TO THE
LAKESHORE...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THIS GREATEST
SNOWFALL AMOUNTS ARE EXPECTED MAINLY ALONG THE LAKESHORE COUNTIES.
FARTHER INLAND CLOSER TO THE US-131 CORRIDOR...TOTALS OF 2 TO 5
INCHES WILL BE MORE COMMON...WITH EVEN LESSER AMOUNTS FARTHER
EAST.
THE SNOW WILL DIMINISH INTO SATURDAY NIGHT WITH SOME SUNSHINE
EXPECTED BY SUNDAY. THEN ANOTHER PERIOD OF SNOW IS EXPECTED FOR
MONDAY AND MONDAY NIGHT. WITH MORE SNOW POSSIBLE AGAIN BY THE END
OF THE WORK WEEK.
&&
.UPDATE...
ISSUED AT 1053 EST FRI FEB 15 2013
TRIMMED BACK SNOW ACCUMULATIONS TODAY BASED ON LATEST OBSERVATIONS
AND MODEL GUIDANCE. LATEST RUNS OF THE RAP MODEL SUGGEST ACCUMULATING
SNOW WILL BE DELAYED UNTIL AFTER 6 TO 7 PM TONIGHT. ALSO LOWERED
INLAND SNOW AMOUNTS OVERALL AS WE EXPECT A FAIRLY SHARP DROP OFF
IN ACCUMULATIONS AWAY FROM THE LAKE SHORE BASED ON THE REASONING
IN THE PREVIOUS DISCUSSION REGARDING CROSS HAIR SIGNATURE
PLACEMENT AND LIKELY INLAND CELLULAR NATURE OF PRECIPITATION
SATURDAY. WILL BE ISSUING AN ADVISORY UPDATE SHORTLY TO REFLECT
THIS CHANGE IN THINKING.
WE ARE LOOKING AT THE POTENTIAL FOR SIGNIFICANT SNOWFALL ENHANCEMENT
ACROSS OUR NORTHERN ZONES AFTER MIDNIGHT AS THE NAM SUGGESTS A
MESOLOW WILL ZIP SOUTHEAST THROUGH LUDINGTON. THIS WILL BE
SOMETHING TO WATCH FOR THE AFTERNOON UPDATE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 342 AM EST FRI FEB 15 2013
HAVE DECIDED TO GO WITH A LAKE EFFECT SNOW ADVISORY FOR ROUGHLY THE
WESTERN HALF OF THE CWA STARTING LATE THIS AFTERNOON AND CONTINUING
INTO SATURDAY EVENING.
LONG DURATION LAKE EFFECT EVENT WILL RAMP UP LATE THIS AFTERNOON A
STRONG WAVE ENERGY PIVOTS IN. INVERSION HEIGHTS WILL CLIMB LEADING
TO AN INCREASED INTENSITY TO THE THE SNOW SHOWERS. FAVORABLE OMEGA
CROSS HAIR SIGNATURE WITHIN THE DGZ LINES UP ALONG THE LAKE SHORE
COUNTIES BY THIS EVENING AND REMAINS PERSISTENT RIGHT INTO SATURDAY
EVENING. MEAN FLOW WILL WAVER SOMEWHAT...SO NOT SURE HOW PERSISTENT
THE SNOW WILL BE AT ANY ONE SPOT...HENCE THE ADVISORY VERSUS A
WARNING. THE FLOW WILL BE 290-300 MUCH OF TONIGHT...BUT THEN IT
BECOMES 310-340 FOR SATURDAY/SATURDAY EVENING WHICH WILL SHIFT THE
SNOW BANDS A BIT.
ANOTHER CONSIDERATION WILL BE THE IMPACT OF THE HIGHER SUN ANGLE
THIS TIME OF YEAR. WE ARE GETTING INTO THAT TIME OF YEAR WHERE THE
LAKE EFFECT CAN BECOME MORE CELLULAR DUE TO DAYTIME CONVECTIVE
ELEMENTS. THIS COULD ALSO LOWER ACCUMS A BIT...OR AT LEAST AFFECT A
PERSISTENT DAYTIME HEAVY SNOW BAND.
ALL IN ALL...EXPECT SOME AREAS ALONG THE LAKE SHORE COUNTIES MAY SEE
UP TO NINE INCHES OF SNOW OVER THE 30 HOUR HEADLINE PERIOD. AMOUNTS
WILL LOWER FURTHER INLAND...BUT THE U.S. 131 COUNTIES WILL STILL SEE
A PERSISTENT SNOW WITH 4 TO 8 INCHES POSSIBLE THERE. EASTERN
COUNTIES WILL SEE SNOW TOO DUE THE SYNOPTIC SHORT WAVE AND SOME LAKE
ENHANCEMENT. FEEL A 2 TO 4 INCH ACCUM SHOULD OCCUR OVER THE SAME
30 HOUR PERIOD.
OTHERWISE...UNTIL WE SEE THE RAMP UP LATE THIS AFTERNOON...THE SNOW
SHOWERS WILL CONTINUE ON A LIGHTER RATE. INVERSION LEVELS STAY
AROUND 5K FEET UNTIL THE SHORT WAVE ARRIVES.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 342 AM EST FRI FEB 15 2013
TWO STORMS ARE EXPECTED NEXT WEEK AND THE SECOND ONE COULD BE MAJOR.
FIRST UP...A CLIPPER MOVES TOWARDS LOWER MICHIGAN ON MONDAY WHILE
PHASING WITH A SOUTHERN STREAM LOW RIGHT OVER LOWER MICHIGAN.
FORECAST CONFIDENCE IS HIGH IN THAT THE MODELS HAVE AGREED ON A RAIN
AND SNOW MIX MOVING IN LATE MONDAY...CHANGING TO SNOW MONDAY NIGHT.
THIS IS FOLLOWED BY WEST FLOW LAKE EFFECT SNOW FROM TUESDAY
AFTERNOON INTO WEDNESDAY.
SFC AND SHORTWAVE UPPER RIDGING MOVES IN TO END THE LAKE EFFECT ON
WEDNESDAY NIGHT...BUT THE LULL WILL BE SHORT LIVED AS A STORM
APPEARS TO BE TAKING SHAPE ACROSS THE PLAINS. THE GULF IS WIDE OPEN
FOR THIS ONE AND A COLD SFC HIGH IS IN PLACE ACROSS EASTERN CANADA.
MODELS HAVE SHOWN THIS STORM FOR A COUPLE DAYS NOW WITH PRETTY GOOD
CONSISTENCY. THURSDAY COULD SEE THE ONSET OF THE STORM WITH SNOW
BREAKING OUT LATE IN THE AFTERNOON...ALTHOUGH BOTH THE GFS AND ECMWF
SHOW THE HEAVIER SNOW NOT ARRIVING UNTIL THURSDAY NIGHT OR FRIDAY.
EVEN AT THIS LONG RANGE THE MODELS ARE SHOWING STRONG F-GEN
POTENTIAL SO THIS COULD BE THE BIGGEST SYNOPTIC SNOW EVENT OF THE
WINTER SO FAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 647 AM EST FRI FEB 15 2013
VFR CONDITIONS EXPECTED TO PREVAIL THIS MORNING BUT LAKE EFFECT
SNOW SHOWERS WILL START THIS AFTERNOON WITH IFR CONDITIONS
EXPECTED FROM MKG TO AZO AND POSSIBLY INTO BTL AND GRR AT TIMES
TONIGHT.
&&
.MARINE...
ISSUED AT 1053 EST FRI FEB 15 2013
KEPT THE SMALL CRAFT ADVISORY INTACT...BUT THERE ARE INDICATIONS
WE WILL STAY BELOW THRESHOLDS AFTER THIS EVENING. WE ARE CONSIDERING
SCALING BACK THE DURATION OF THE SCA FOR THE AFTERNOON UPDATE.
&&
.HYDROLOGY...
ISSUED AT 342 AM EST FRI FEB 15 2013
ONLY ONE FLOOD ADVISORY REMAINS ON THE PERE MARQUETTE AT
SCOTTVILLE. THIS IS EXPECTED TO REMAIN FAIRLY STEADY OVER THE SHORT
TERM. OTHERWISE WITH THE POLAR AIR COMING IN ANY MELT OFF HAS ENDED
THROUGH AT LEAST THE WEEKEND.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY FROM 4 PM THIS AFTERNOON TO 10 PM EST
SATURDAY FOR MIZ037-043-050-056-064-071-072.
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SATURDAY FOR MIZ038-044-057-065-073.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM EST SUNDAY FOR LMZ844>849.
&&
$$
UPDATE...TJT
SYNOPSIS...TJT
SHORT TERM...JK
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...JK
MARINE...TJT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
650 AM EST FRI FEB 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EST FRI FEB 15 2013
THE LOW THAT AFFECTED THE SOUTHERN PART OF THE CWA YESTERDAY MORNING
HAS LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. RUC ANALYZED
850MB TEMPS ARE AROUND -16C OVER LAKE SUPERIOR AND NORTH-NORTHWEST
WINDS ALOFT HAS LED TO LAKE EFFECT SNOW OVER PORTIONS OF LAKE
SUPERIOR EARLY THIS MORNING. THE BEST SNOW HAS BEEN OCCURRING OVER
IN THE MULTI-BANDED SNOW OVER EASTERN LAKE SUPERIOR...WHERE
INVERSION HEIGHTS ARE AROUND 8KFT BASED OF KMQT RADAR AND THERE IS
ENOUGH MOISTURE PRESENT. FARTHER WEST...DRIER AIR THIS EVENING HAS
LIMITED MUCH OF THE LAKE EFFECT SNOW THUS FAR. BUT WITH A SHORTWAVE
JUST NORTHWEST OF LAKE SUPERIOR EXPECTED TO INCREASE MOISTURE ACROSS
THE AREA...HAVE SEEN A SLIGHT INCREASE IN COVERAGE ON SATELLITE
BETWEEN THE HIGHER CLOUDS. THIS WILL ALSO INCREASE THE INVERSION
HEIGHTS FROM 3-4KFT TO 6-8KFT OVER THE WEST. THUS...EXPECT THE LAKE
EFFECT TO TO CONTINUE TO INCREASE IN INTENSITY/COVERAGE FOR BOTH
WEST/EAST THROUGH THE MORNING HOURS FOR LOCATIONS FAVORED BY
NORTH-NORTHWEST WINDS. WITH MUCH OF THE CONVECTIVE PORTION OF THE
CLOUD WITHIN THE DGZ...EXPECT VERY FLUFFY LAKE EFFECT AND SNOW
RATIOS IN THE 30-1 RANGE. THIS WILL ALLOW FOR QUICK ACCUMULATIONS IN
THE STRONGER BANDS...ESPECIALLY SINCE WINDS WILL HAVE DECREASED FROM
THE 20-30KTS SEEN AROUND MIDNIGHT. ONE ITEM OF CONCERN FOR THE
INTENSITY THIS MORNING OVER THE WEST...ESPECIALLY OVER THE
KEWEENAW...IS THE 30 DEGREES OF SHEAR BETWEEN THE TOP OF THE
INVERSION /800MB/ AND THE MIDDLE OF THE CONVECTIVE CLOUD /900MB/.
THIS MAY LIMIT THE DEEP AND ORGANIZED BANDS THAT WOULD PROMOTE VERY
HEAVY SNOW.
AS THIS SHORTWAVE DEPARTS LATE THIS MORNING AND INTO THE
AFTERNOON...WOULD THINK THE LAKE EFFECT WILL DIMINISH SOME AS
DIURNAL MIXING HELPS REDUCE THE INTENSITY OF THE BANDS OVER THE
WEST. IN ADDITION...THE DEEPER MOISTURE SLIDES MORE OVER THE EASTERN
LAKE WHILE WINDS BACK TO THE NORTHWEST. THIS WILL HELP REDUCE THE
INTENSITY OF THE BANDS SLIGHTLY...BUT THE BACKING WINDS WILL CAUSE
THE HEAVIEST SNOW TO SHIFT FROM THE MORE NNW FAVORED AREAS TO NW
AREAS. ALTHOUGH THIS WILL SPREAD THE LAKE EFFECT TO MORE AREAS...IT
MIGHT CAUSE SOME LIMITATION IN THE HIGHER SNOWFALL AMOUNTS IN ONE
LOCATION TO BE PRIMARILY IN THE ADVISORY CRITERIA CATEGORY. HIGHER
RESOLUTION MODELS DO PICK UP ON BOTH OF THESE FEATURES WELL AND
WILL FOLLOW THEIR TIMING FOR THE MOVEMENT AND INTENSITY FOR THIS
AFTERNOON. OVER THE EAST...INVERSION HEIGHTS OVER THE EAST RISE TO
8-10KFT THIS AFTERNOON AND CONTINUE INTO THE EVENING. WITH THE
DEEPER MOISTURE FROM THE SHORTWAVE AND SOME ENHANCED CONVERGENCE ON
THE SOUTHWEST EDGE OF THE LAKE EFFECT...EXPECT A FAIRLY HEAVY BAND
OR TWO WITHIN THE MULTI-BAND SNOW TO SETUP SOMEWHERE BETWEEN
MUNISING AND GRAND MARAIS. THIS NW WIND WILL ALSO LEAD TO
AN INCREASED PERIOD OF SNOW FOR NORTHERN LUCE COUNTY LATER THIS
AFTERNOON AND INTO THE EARLY EVENING. THIS IS DUE TO THE LONGER
FETCH THAN THEY WILL SEE FOR THE FIRST PART OF TODAY WITH THE
NORTHERLY WINDS. THERE IS THE POTENTIAL FOR SOME HEAVIER SNOWFALL
RATES AND ADVISORY SNOWFALL DURING THAT PERIOD...SO FELT
COMFORTABLE ISSUING AN ADVISORY EVEN THOUGH THERE IS SOME CONCERN
ON THE TIMING OF WHEN THE BAND WILL BACK TO THE WEST TONIGHT AS
WINDS SHIFT TO THE NORTHEAST.
COLDER AIR ARRIVES TONIGHT...WITH 850MB TEMPS FALLING TOWARDS -22C
OVER THE WEST AND -20C OVER THE EAST. OVER THE WEST...THE PRODUCES
SOME CONCERN AS IT WILL PUT A PORTION OF THE CONVECTIVE CLOUD LAYER
AT THE TOP OF OR ABOVE THE DGZ AND LIKELY REDUCE THE SNOW RATIOS
SOMEWHAT. BUT INCREASED CONVERGENCE AS WINDS VEER TO A MORE
NORTHERLY DIRECTION DURING THE EVENING...DUE TO THE APPROACHING HIGH
IN THE NORTHERN PLAINS...WILL HELP INCREASE THE
INTENSITY OF THE SNOW BEFORE RETURNING TO MORE OF A GENERAL
MULTI-BAND LAKE EFFECT DURING THE OVERNIGHT HOURS. ALSO...ANOTHER
WEAK SHORTWAVE IN THE UPPER TROUGH WILL HELP INCREASE MOISTURE AND
KEEP INVERSION HEIGHTS IN THE 7-8KFT RANGE.
OVER THE EAST...THERE DOES SEEM TO BE A SLIGHT SLOWDOWN TO THE
WESTWARD TRANSITION OF THE LAKE EFFECT FROM THE NORTHWEST FAVORED
AREAS TO MORE NORTHERLY COMPARED TO 24HRS AGO...AS THE SURFACE
TROUGH OVER EASTERN LAKE SUPERIOR WEAKENS AND LAND BREEZE INFLUENCES
OFF ONTARIO TAKE OVER. SOME OF THE HIGHER RESOLUTION MODEL RUNS EVEN
TRY TO DEVELOP A WEAK MESO-LOW...WHICH WOULD COMPLICATE MATTERS
FURTHER. THUS...HAVE SLOWED THE WESTWARD TRANSITION A TOUCH AS THE
STRONGER BANDS MAKE THE WESTWARD TRACK ACROSS ALGER AND NORTHERN
SCHOOLCRAFT COUNTIES DURING THE NIGHT. THE INCREASED CONVERGENCE
WITHIN THIS BAND SHOULD LEAD TO SOME HEAVY SNOWFALL RATES AS IT
TRANSITIONS TO THE WEST.
ALL IN ALL...WILL LEAVE THE WARNING HEADLINES AS IS AND ADD
THE LUCE ADVISORY. THERE IS SOME SLIGHT CONCERN ON GETTING WARNING
AMOUNTS IN A WIDESPREAD AREA OF GOGEBIC/ONTONAGON
COUNTIES...BUT SHOULD EASILY SEE THE 12 INCHES IN 24HRS OVER
THE PORKIES. THE ONE QUESTION TO CARRY FORWARD TO THE DAY SHIFT IS
THE BORDERLINE ADVISORY SNOW FOR NORTHERN HOUGHTON AND KEWEENAW
COUNTIES. DIDN/T HAVE A GOOD FEELING ON ADVISORY AMOUNTS FOR
TODAY...ALTHOUGH WITH THE FLUFFY NATURE...COULD SEE A QUICK 4 INCHES
IN A LOCATION IF A BAND SETS UP FOR A FEW HOURS THIS MORNING. IN
ADDITION...WITH THE WINDS BACKING TO THE NW THIS AFTERNOON AND THEN
MORE OUT OF THE NORTH TONIGHT...WOULDN/T THINK THEY WOULD SEE A
PERSISTENT AREA OF TO RAISE CONFIDENCE ENOUGH FOR AN ADVISORY AT
THIS TIME. WITH THE MORE FAVORABLE MOISTURE TONIGHT AND SOME
ENHANCED CONVERGENCE...WOULD THINK THE BEST POTENTIAL FOR ADVISORY
SNOW WOULD BE OVER NORTHERN HOUGHTON COUNTY TOWARDS TWIN LAKES AND
THE DAY SHIFT MAY NEED TO SEE IF THAT IDEA CONTINUES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EST FRI FEB 15 2013
SATURDAY...HIGHER RES MODELS SUGGEST THAT LAKE INDUCED TROUGHING WILL
FOCUS STRONGEST LOW LEVEL CONV AND LES INTO NORTH CENTRAL UPPER MI
BTWN MARQUETTE AND MUNISING. CONTINUED HIGH SLR NEAR 30/1 WOULD
SUPPORT SOME SNOW TOTALS IN THE 4 TO 7 INCH RANGE. CONFIDENCE IN THE
LOCATION OF THIS MESO SCALE FEATURE IS LIMITED BUT A HEADLINE FOR THE FAR
EASTERN PORTION OF MARQUETTE COUNTY MAY BE NECESSARY IF MODEL
AGREEMENT IS CONSISTENT. OVER THE WEST...LES WILL DIMINISH MORE
QUICKLY WITH THE SFC RIDGE AND DRIER AIR BUILDING INTO THE AREA
LEADING TO ADDITIONAL TOTALS ONLY IN THE 1 TO 4 INCH RANGE. A SHALLOW
DGZ WITH LESS FAVORABLE SLR WOULD ALSO LIMIT ACCUMULATION POTENTIAL.
SAT NIGHT...ALTHOUGH LES WILL CONTINUE TO DIMINISH WITH THE RIDGE
BUILDING INTO THE AREA...LIGHT WIND FIELDS AND CONTINUED LOW LEVEL
CONV...ESPECIALLY NEAR THE SHORELINE VCNTY KP53 COULD PRODUCE
SEVERAL ADDITIONAL INCHES OF SNOW. OTHERWISE...CLEARING WITH
FAVORABLE RADIATIONAL COOLING CONDITIONS WILL SUPPORT MIN TEMPS NEAR
THE LOWER END OF GUIDANCE...INTO THE -15F TO -20F RANGE INTERIOR
WEST HALF.
SUN AND SUN NIGHT...A PROGRESSIVE PATTERN WITH THE SFC RIDGE
SHIFTING TO THE EAST...A TROUGH INTO THE NRN PLAINS TO THE UPPER MS
VALLEY AND A STRENGTHENING WAA PATTERN WILL ALLOW MOISTURE TO
INCREASE. BOTH THE GFS AND ECMWF SUGGEST THE STRONGEST ISENTROPIC
LIFT WILL REMAIN NORTH OF THE CWA WITH ONLY CHANCE POPS FOR LIGHT
SNOW BY LATE SUN NIGHT.
MON INTO MON NIGHT...MODELS WERE SIMILAR WITH A MID/UPPER LEVEL
TROUGH INTO THE WRN GREAT LAKES. THE ECMWF WAS A BIT SLOWER AND MORE
AGGRESSIVE IN DIGGING THE TROUGH AND SFC LOW TO THE SOUTH COMPARED
TO THE GFS...BUT NOT AS MUCH AS THE CMC...RESULTING IN GREATER PCPN
ACROSS UPPER MICHIGAN. WITH SUFFICIENT MOISTURE INFLOW BRINGING PWAT
TO NEAR 200 PCT NORMAL THE POTENTIAL REMAINS FOR MODERATE SNOW
ACCUMULATIONS WITH THE SYSTEM.
TUE-WED...SIGNFICANT/HEAVY LES WILL BE POSSIBLE IN THE WAKE OF THE
LOW WITH STRONG CAA DROPPING 850 MB TEMPS INTO THE -15C TO -20C
RANGE ALONG WITH CYCLONIC NNW FLOW AND ABUNDANT 850-700
MOISTURE...PER ECMWF. LES SHOULD DIMINISH WED AS RIDGING AGAIN
BUILDS INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 649 AM EST FRI FEB 15 2013
LAKE EFFECT SNOW SHOWERS WILL BE ON THE INCREASE AT KCMX/KIWD
THROUGH THE MORNING HOURS. EXPECT THE STRONGEST SNOW THROUGH MUCH
OF THE DAYTIME HOURS AT KIWD WITH THE MORE FAVORABLE AND
CONVERGENT FLOW THIS MORNING. BUT AS WINDS BACK MORE TO
THE NORTHWEST...EXPECT CONDITIONS TO DROP TO IFR/MVFR AT
KCMX WHILE THEY BECOME LESS FAVORABLE AT KIWD. EXPECT PERIODS OF
ALTERNATE LANDING MINIMUMS VISIBILITIES TONIGHT AS LOW LEVEL
CONVERGENCE INCREASES WITH WINDS VEERING TO THE NNW...INCREASING
THE INTENSITY OF THE SNOW.
AT KSAW...UNFAVORABLE DOWNSLOPING NW FLOW WILL GENERALLY KEEP
BORDERLINE MVFR/VFR CEILINGS THROUGH THE PERIOD WITH OCCASIONAL
SNOW SHOWERS FROM ENHANCED SNOW OFF THE HURON MOUNTAINS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST FRI FEB 15 2013
NORTHWEST WINDS OF 20-30KTS WILL DIMINISH TODAY AS HIGH PRESSURE IN
THE NORTHERN PLAINS SLOWLY SHIFTS EAST INTO THE UPPER GREAT LAKES.
THIS WILL CONTINUE TO DIMINISH THE WINDS ON THROUGH SATURDAY.
BEFORE THE WINDS DIMINISH...HEAVY FREEZING SPRAY IS EXPECTED OVER
PORTIONS OF LAKE SUPERIOR THROUGH TONIGHT. AS THE HIGH SHIFTS EAST
ON SUNDAY A LOW PRESSURE SYSTEM WILL APPROACH THE UPPER GREAT LAKES
ON MONDAY AND MOVE THROUGH ON TUESDAY. THIS WILL BRING INCREASING
SOUTHERLY FLOW ON MONDAY...TO 25KTS OVER THE EAST...AND THEN STRONG
NORTHERLY WINDS BEHIND THE LOW ON TUESDAY AFTERNOON...TO 30KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST SATURDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST SATURDAY FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ SATURDAY FOR
MIZ002-009.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST SATURDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
501 AM EST FRI FEB 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EST FRI FEB 15 2013
THE LOW THAT AFFECTED THE SOUTHERN PART OF THE CWA YESTERDAY MORNING
HAS LEFT A SURFACE TROUGH OVER EASTERN LAKE SUPERIOR. RUC ANALYZED
850MB TEMPS ARE AROUND -16C OVER LAKE SUPERIOR AND NORTH-NORTHWEST
WINDS ALOFT HAS LED TO LAKE EFFECT SNOW OVER PORTIONS OF LAKE
SUPERIOR EARLY THIS MORNING. THE BEST SNOW HAS BEEN OCCURRING OVER
IN THE MULTI-BANDED SNOW OVER EASTERN LAKE SUPERIOR...WHERE
INVERSION HEIGHTS ARE AROUND 8KFT BASED OF KMQT RADAR AND THERE IS
ENOUGH MOISTURE PRESENT. FARTHER WEST...DRIER AIR THIS EVENING HAS
LIMITED MUCH OF THE LAKE EFFECT SNOW THUS FAR. BUT WITH A SHORTWAVE
JUST NORTHWEST OF LAKE SUPERIOR EXPECTED TO INCREASE MOISTURE ACROSS
THE AREA...HAVE SEEN A SLIGHT INCREASE IN COVERAGE ON SATELLITE
BETWEEN THE HIGHER CLOUDS. THIS WILL ALSO INCREASE THE INVERSION
HEIGHTS FROM 3-4KFT TO 6-8KFT OVER THE WEST. THUS...EXPECT THE LAKE
EFFECT TO TO CONTINUE TO INCREASE IN INTENSITY/COVERAGE FOR BOTH
WEST/EAST THROUGH THE MORNING HOURS FOR LOCATIONS FAVORED BY
NORTH-NORTHWEST WINDS. WITH MUCH OF THE CONVECTIVE PORTION OF THE
CLOUD WITHIN THE DGZ...EXPECT VERY FLUFFY LAKE EFFECT AND SNOW
RATIOS IN THE 30-1 RANGE. THIS WILL ALLOW FOR QUICK ACCUMULATIONS IN
THE STRONGER BANDS...ESPECIALLY SINCE WINDS WILL HAVE DECREASED FROM
THE 20-30KTS SEEN AROUND MIDNIGHT. ONE ITEM OF CONCERN FOR THE
INTENSITY THIS MORNING OVER THE WEST...ESPECIALLY OVER THE
KEWEENAW...IS THE 30 DEGREES OF SHEAR BETWEEN THE TOP OF THE
INVERSION /800MB/ AND THE MIDDLE OF THE CONVECTIVE CLOUD /900MB/.
THIS MAY LIMIT THE DEEP AND ORGANIZED BANDS THAT WOULD PROMOTE VERY
HEAVY SNOW.
AS THIS SHORTWAVE DEPARTS LATE THIS MORNING AND INTO THE
AFTERNOON...WOULD THINK THE LAKE EFFECT WILL DIMINISH SOME AS
DIURNAL MIXING HELPS REDUCE THE INTENSITY OF THE BANDS OVER THE
WEST. IN ADDITION...THE DEEPER MOISTURE SLIDES MORE OVER THE EASTERN
LAKE WHILE WINDS BACK TO THE NORTHWEST. THIS WILL HELP REDUCE THE
INTENSITY OF THE BANDS SLIGHTLY...BUT THE BACKING WINDS WILL CAUSE
THE HEAVIEST SNOW TO SHIFT FROM THE MORE NNW FAVORED AREAS TO NW
AREAS. ALTHOUGH THIS WILL SPREAD THE LAKE EFFECT TO MORE AREAS...IT
MIGHT CAUSE SOME LIMITATION IN THE HIGHER SNOWFALL AMOUNTS IN ONE
LOCATION TO BE PRIMARILY IN THE ADVISORY CRITERIA CATEGORY. HIGHER
RESOLUTION MODELS DO PICK UP ON BOTH OF THESE FEATURES WELL AND
WILL FOLLOW THEIR TIMING FOR THE MOVEMENT AND INTENSITY FOR THIS
AFTERNOON. OVER THE EAST...INVERSION HEIGHTS OVER THE EAST RISE TO
8-10KFT THIS AFTERNOON AND CONTINUE INTO THE EVENING. WITH THE
DEEPER MOISTURE FROM THE SHORTWAVE AND SOME ENHANCED CONVERGENCE ON
THE SOUTHWEST EDGE OF THE LAKE EFFECT...EXPECT A FAIRLY HEAVY BAND
OR TWO WITHIN THE MULTI-BAND SNOW TO SETUP SOMEWHERE BETWEEN
MUNISING AND GRAND MARAIS. THIS NW WIND WILL ALSO LEAD TO
AN INCREASED PERIOD OF SNOW FOR NORTHERN LUCE COUNTY LATER THIS
AFTERNOON AND INTO THE EARLY EVENING. THIS IS DUE TO THE LONGER
FETCH THAN THEY WILL SEE FOR THE FIRST PART OF TODAY WITH THE
NORTHERLY WINDS. THERE IS THE POTENTIAL FOR SOME HEAVIER SNOWFALL
RATES AND ADVISORY SNOWFALL DURING THAT PERIOD...SO FELT
COMFORTABLE ISSUING AN ADVISORY EVEN THOUGH THERE IS SOME CONCERN
ON THE TIMING OF WHEN THE BAND WILL BACK TO THE WEST TONIGHT AS
WINDS SHIFT TO THE NORTHEAST.
COLDER AIR ARRIVES TONIGHT...WITH 850MB TEMPS FALLING TOWARDS -22C
OVER THE WEST AND -20C OVER THE EAST. OVER THE WEST...THE PRODUCES
SOME CONCERN AS IT WILL PUT A PORTION OF THE CONVECTIVE CLOUD LAYER
AT THE TOP OF OR ABOVE THE DGZ AND LIKELY REDUCE THE SNOW RATIOS
SOMEWHAT. BUT INCREASED CONVERGENCE AS WINDS VEER TO A MORE
NORTHERLY DIRECTION DURING THE EVENING...DUE TO THE APPROACHING HIGH
IN THE NORTHERN PLAINS...WILL HELP INCREASE THE
INTENSITY OF THE SNOW BEFORE RETURNING TO MORE OF A GENERAL
MULTI-BAND LAKE EFFECT DURING THE OVERNIGHT HOURS. ALSO...ANOTHER
WEAK SHORTWAVE IN THE UPPER TROUGH WILL HELP INCREASE MOISTURE AND
KEEP INVERSION HEIGHTS IN THE 7-8KFT RANGE.
OVER THE EAST...THERE DOES SEEM TO BE A SLIGHT SLOWDOWN TO THE
WESTWARD TRANSITION OF THE LAKE EFFECT FROM THE NORTHWEST FAVORED
AREAS TO MORE NORTHERLY COMPARED TO 24HRS AGO...AS THE SURFACE
TROUGH OVER EASTERN LAKE SUPERIOR WEAKENS AND LAND BREEZE INFLUENCES
OFF ONTARIO TAKE OVER. SOME OF THE HIGHER RESOLUTION MODEL RUNS EVEN
TRY TO DEVELOP A WEAK MESO-LOW...WHICH WOULD COMPLICATE MATTERS
FURTHER. THUS...HAVE SLOWED THE WESTWARD TRANSITION A TOUCH AS THE
STRONGER BANDS MAKE THE WESTWARD TRACK ACROSS ALGER AND NORTHERN
SCHOOLCRAFT COUNTIES DURING THE NIGHT. THE INCREASED CONVERGENCE
WITHIN THIS BAND SHOULD LEAD TO SOME HEAVY SNOWFALL RATES AS IT
TRANSITIONS TO THE WEST.
ALL IN ALL...WILL LEAVE THE WARNING HEADLINES AS IS AND ADD
THE LUCE ADVISORY. THERE IS SOME SLIGHT CONCERN ON GETTING WARNING
AMOUNTS IN A WIDESPREAD AREA OF GOGEBIC/ONTONAGON
COUNTIES...BUT SHOULD EASILY SEE THE 12 INCHES IN 24HRS OVER
THE PORKIES. THE ONE QUESTION TO CARRY FORWARD TO THE DAY SHIFT IS
THE BORDERLINE ADVISORY SNOW FOR NORTHERN HOUGHTON AND KEWEENAW
COUNTIES. DIDN/T HAVE A GOOD FEELING ON ADVISORY AMOUNTS FOR
TODAY...ALTHOUGH WITH THE FLUFFY NATURE...COULD SEE A QUICK 4 INCHES
IN A LOCATION IF A BAND SETS UP FOR A FEW HOURS THIS MORNING. IN
ADDITION...WITH THE WINDS BACKING TO THE NW THIS AFTERNOON AND THEN
MORE OUT OF THE NORTH TONIGHT...WOULDN/T THINK THEY WOULD SEE A
PERSISTENT AREA OF TO RAISE CONFIDENCE ENOUGH FOR AN ADVISORY AT
THIS TIME. WITH THE MORE FAVORABLE MOISTURE TONIGHT AND SOME
ENHANCED CONVERGENCE...WOULD THINK THE BEST POTENTIAL FOR ADVISORY
SNOW WOULD BE OVER NORTHERN HOUGHTON COUNTY TOWARDS TWIN LAKES AND
THE DAY SHIFT MAY NEED TO SEE IF THAT IDEA CONTINUES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EST FRI FEB 15 2013
SATURDAY...HIGHER RES MODELS SUGGEST THAT LAKE INDUCED TROUGHING WILL
FOCUS STRONGEST LOW LEVEL CONV AND LES INTO NORTH CENTRAL UPPER MI
BTWN MARQUETTE AND MUNISING. CONTINUED HIGH SLR NEAR 30/1 WOULD
SUPPORT SOME SNOW TOTALS IN THE 4 TO 7 INCH RANGE. CONFIDENCE IN THE
LOCATION OF THIS MESO SCALE FEATURE IS LIMITED BUT A HEADLINE FOR THE FAR
EASTERN PORTION OF MARQUETTE COUNTY MAY BE NECESSARY IF MODEL
AGREEMENT IS CONSISTENT. OVER THE WEST...LES WILL DIMINISH MORE
QUICKLY WITH THE SFC RIDGE AND DRIER AIR BUILDING INTO THE AREA
LEADING TO ADDITIONAL TOTALS ONLY IN THE 1 TO 4 INCH RANGE. A SHALLOW
DGZ WITH LESS FAVORABLE SLR WOULD ALSO LIMIT ACCUMULATION POTENTIAL.
SAT NIGHT...ALTHOUGH LES WILL CONTINUE TO DIMINISH WITH THE RIDGE
BUILDING INTO THE AREA...LIGHT WIND FIELDS AND CONTINUED LOW LEVEL
CONV...ESPECIALLY NEAR THE SHORELINE VCNTY KP53 COULD PRODUCE
SEVERAL ADDITIONAL INCHES OF SNOW. OTHERWISE...CLEARING WITH
FAVORABLE RADIATIONAL COOLING CONDITIONS WILL SUPPORT MIN TEMPS NEAR
THE LOWER END OF GUIDANCE...INTO THE -15F TO -20F RANGE INTERIOR
WEST HALF.
SUN AND SUN NIGHT...A PROGRESSIVE PATTERN WITH THE SFC RIDGE
SHIFTING TO THE EAST...A TROUGH INTO THE NRN PLAINS TO THE UPPER MS
VALLEY AND A STRENGTHENING WAA PATTERN WILL ALLOW MOISTURE TO
INCREASE. BOTH THE GFS AND ECMWF SUGGEST THE STRONGEST ISENTROPIC
LIFT WILL REMAIN NORTH OF THE CWA WITH ONLY CHANCE POPS FOR LIGHT
SNOW BY LATE SUN NIGHT.
MON INTO MON NIGHT...MODELS WERE SIMILAR WITH A MID/UPPER LEVEL
TROUGH INTO THE WRN GREAT LAKES. THE ECMWF WAS A BIT SLOWER AND MORE
AGGRESSIVE IN DIGGING THE TROUGH AND SFC LOW TO THE SOUTH COMPARED
TO THE GFS...BUT NOT AS MUCH AS THE CMC...RESULTING IN GREATER PCPN
ACROSS UPPER MICHIGAN. WITH SUFFICIENT MOISTURE INFLOW BRINGING PWAT
TO NEAR 200 PCT NORMAL THE POTENTIAL REMAINS FOR MODERATE SNOW
ACCUMULATIONS WITH THE SYSTEM.
TUE-WED...SIGNFICANT/HEAVY LES WILL BE POSSIBLE IN THE WAKE OF THE
LOW WITH STRONG CAA DROPPING 850 MB TEMPS INTO THE -15C TO -20C
RANGE ALONG WITH CYCLONIC NNW FLOW AND ABUNDANT 850-700
MOISTURE...PER ECMWF. LES SHOULD DIMINISH WED AS RIDGING AGAIN
BUILDS INTO THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1232 AM EST FRI FEB 15 2013
ARRIVAL OF DRIER/MORE STABLE AIRMASS SHOWN ON THE 12Z INL RAOB HAS
CAUSED THE LES TO DIMINISH AT THE TAF SITES EARLY THIS MRNG...WITH
VFR/HIER END MVFR CONDITIONS THE RULE AT TAF ISSUANCE. BUT EXPECT AN
UPTICK IN LES INTENSITY BY 12Z MAINLY AT IWD WITH SHARPER LLVL CNVGC
AND MORE FVRBL UPSLOPE NNW FLOW AS COLDER AIR AS WELL AS MORE MID
LVL MSTR SHOWN ON THE 00Z INL RAOB AND UPSTREAM SFC OBS MOVE ACRS
THE LK. SINCE THE FLOW AT CMX WL NOT AS FVRBL THRU MUCH OF TODAY...
MVFR CONDITIONS SHOULD BE THE RULE THERE. IFR WX MAY DVLP BY THIS
EVNG AT THAT SITE WITH SHARPENING LLVL CNVGC. GENERAL DOWNSLOPE WIND
COMPONENT THRU THE FCST PERIOD AT SAW SHOULD MAINTAIN PREDOMINANT
VFR TO OCNL HIER END MVFR CONDITIONS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EST FRI FEB 15 2013
NORTHWEST WINDS OF 20-30KTS WILL DIMINISH TODAY AS HIGH PRESSURE IN
THE NORTHERN PLAINS SLOWLY SHIFTS EAST INTO THE UPPER GREAT LAKES.
THIS WILL CONTINUE TO DIMINISH THE WINDS ON THROUGH SATURDAY.
BEFORE THE WINDS DIMINISH...HEAVY FREEZING SPRAY IS EXPECTED OVER
PORTIONS OF LAKE SUPERIOR THROUGH TONIGHT. AS THE HIGH SHIFTS EAST
ON SUNDAY A LOW PRESSURE SYSTEM WILL APPROACH THE UPPER GREAT LAKES
ON MONDAY AND MOVE THROUGH ON TUESDAY. THIS WILL BRING INCREASING
SOUTHERLY FLOW ON MONDAY...TO 25KTS OVER THE EAST...AND THEN STRONG
NORTHERLY WINDS BEHIND THE LOW ON TUESDAY AFTERNOON...TO 30KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST SATURDAY FOR MIZ006-085.
LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST SATURDAY FOR MIZ007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST /NOON CST/ SATURDAY FOR
MIZ002-009.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST SATURDAY FOR
LSZ264>266.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST THIS EVENING FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1148 PM EST THU FEB 14 2013
.AVIATION...
//DISCUSSION...
AREA OF LIGHT SNOW WITH CLIPPER WILL EXIT EAST OF KMBS/KFNT AS THE
FORECAST PERIOD BEGINS. FURTHER SOUTH...BAND OF LAKE EFFECT SNOW
SHOWERS WILL AFFECT THE I-94 CORRIDOR FOR A FEW HOURS EARLY IN THE
FORECAST BEFORE SHIFTING SOUTH. OTHERWISE...BKN-OVC MVFR CIGS WILL
BE COMMON THROUGHOUT THE FORECAST PERIOD...AVERAGING 1500-2500 THRU
10Z TO 12Z AND 2500-3500 ON FRIDAY.
FOR DTW...CIGS WILL BOUNCE GENERALLY BETWEEN 2-3KFT OVERNIGHT WITH A
FEW SNOW SHOWERS EARLY AS LAKE EFFECT BAND BRUSHES THE AREA. CIGS
WILL RISE CLOSER TO 3500 FEET ON FRIDAY AS COLD...CYCLONIC NORTHWEST
FLOW PERSISTS...WITH A BETTER CHANCE FOR SNOW SHOWERS LATE FRIDAY
NIGHT AS NEXT SHORTWAVE IMPULSE ROTATES SOUTHEAST INTO THE REGION.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FEET THROUGHOUT MUCH
IF NOT ALL OF THE TAF PERIOD.
&&
.PREV DISCUSSION...ISSUED 359 PM EST THU FEB 14 2013
SHORT TERM...THIS EVENING AND TONIGHT
THE VORTICITY RICH POTENTIAL VORTICITY ANOMALY NOW SPINNING ACROSS
CENTRAL LAKE MICHIGAN HAS LED TO A NUMBER OF SPOKES/BANDS OF
PRECIPITATION SLIDING THROUGH LOWER MICHIGAN. SINCE MIDDAY THESE
BANDS HAVE BEEN NOTHING MORE THAN LIGHT RAIN SHOWERS OR SPRINKLES
PER SFC REPORTS AND A NEAR SURFACE MELTING LAYER AT GREATER THAN 4C.
VARIOUS HIRES MODELS ARE SUGGESTING THAT CONVECTION/SHOWER
DEVELOPMENT WILL TAKE PLACE ALONG AND AHEAD OF THE COLD FRONT
BETWEEN 21-00Z. THIS IDEA REMAINS VALID. DIFFICULT TO EVALUATE THE
OVERALL THERMODYNAMIC PROFILE OR HOW MUCH CAPE IS OUT THERE WITH THE
VALID RUC BASED SPC MESOANALYSIS GRAPHIC SHOWING NOTHING IN THE WAY
OF MUCAPE. GOING THROUGH MODEL DATA THOUGH SUGGESTS THAT 50 TO 100
J/KG IS PLAUSIBLE GIVEN SFC/DWPT VALUES THAT ARE ON TARGET.
EVOLUTION OF MODEL SOUNDINGS SUGGESTS THAT IT WILL REQUIRE SOME
COOLING FROM APPROACHING COLD FRONT TO ERODE A LOW CAPPING LAYER TO
ALLOW FOR INITIATION. THE POTENTIAL EXISTS FOR CONVECTION TO YIELD
GRAUPEL/ICE PELLETS. ADDITIONALLY...THERE REMAINS A POSSIBILITY THAT
BURSTS COULD PRODUCE MORE IN THE WAY OF SNOW...AND THE PERCENTAGE OF
OCCURRENCE IS AN UNKNOWN. FARTHER NORTH...EXPECTING THE ACTIVITY TO
FALL AS RAIN...ALTHOUGH THIS AREAS STANDS A BETTER CHANCE TO SEE
SOME LIGHT SNOW WITH MINOR ACCUMULATIONS. WINDS WILL INCREASE...UP
TO 25 TO 30 MPH...AS WIND DIRECTIONS SHIFT FROM 200 TO 240 POST COLD
FRONT.
ISENTROPIC DOWNGLIDE WILL COMMENCE BETWEEN 00-03Z...KICKING IT UP A
COUPLE OF GEARS BETWEEN 03-09Z. THE COLUMN IS SHOWN TO BECOME QUITE
STABLE IN THE 900-700MB LAYER...TOO STABLE TO SUPPORT MUCH IN THE
WAY OF SNOW TONIGHT. NAM IS HIGHLIGHTING SOME LAKE EFFECT
BANDING/ENHANCED CONVERGENCE ACROSS SW LOWER LATE TONIGHT. DID LEAVE
A LOW CHANCE FOR LIGHT IN ACROSS THE SOUTH AS THERE IS SOME
POTENTIAL FOR SOME SNOWFLAKES TO MAKE THE TRIP ACROSS THE PENINSULA.
OTHERWISE...FLURRIES FOR A MAJORITY OF THE AREA. LOWS TONIGHT WERE
DERIVED FROM A BLEND OF RAW MODEL OUTPUT...A DECENT ADJUSTMENT
DOWNWARD UPPER TEENS NORTH TO UPPER 20S SOUTH.
LONG TERM...FRIDAY THROUGH NEXT THURSDAY
LONGWAVE TROUGH WILL LOCK COOL AIR IN PLACE OVER THE GREAT LAKES
THROUGH THE WEEKEND...AS H850 TEMPS DROP TO AROUND -18C (BY SAT
NIGHT) IN THE POST-FRONTAL AIRMASS. CHANCES FOR ACCUMULATING SNOW
LOOK FAIRLY LOW FOR THIS SIDE OF THE STATE...AND WILL BE DUE TO A
COMBINATION OF WEAK SHORTWAVES AND LAKE EFFECT. SHORTWAVES MAY BE A
LITTLE HARD TO TIME DUE TO SMALL NATURE AND LACK OF SAMPLING (AT
THIS TIME) AND FORECAST ADJUSTMENTS ARE STILL POSSIBLE AS CHANGES IN
TIMING/LOCATION OF SHORTWAVES IMPACT LAKE EFFECT PARAMETERS SUCH AS
STABILITY...MOISTURE...AND WIND SPEED AND TRAJECTORY.
MODEL GUIDANCE TAKES THE WAVE NOW DROPPING THROUGH SOUTHERN MANITOBA
ACROSS NORTHERN LOWER MICHIGAN TOMORROW...WHILE ALSO SHEARING APART
ANOTHER SHORTWAVE AS IT DROPS FROM THE DAKOTAS DOWN INTO THE OHIO
VALLEY. VERY WEAK LIFT ASSOCIATED WITH THESE WAVES COULD PROVIDE A
BRIEF SNOW SHOWER TO THE AREA...BUT MAINLY EXPECT A LOT OF CLOUDS
AND FLURRIES AROUND DUE TO LAKE EFFECT AND STEEP LAPSE RATES. DID
KEEP LOW POPS IN THE FORECAST...BUT THINK FAIRLY WEAK FLOW OVER THE
LAKE AND ONLY MODERATE INSTABILITY SHOULD KEEP ACCUMULATIONS TO OUR
WEST. SIMILAR POP FORECAST EXISTS ON FRIDAY NIGHT. ALTHOUGH MOISTURE
DEPTH AND COLD AIR ADVECTION WILL INCREASE...MEAN SURFACE-850MB FLOW
ACROSS LAKE MICHIGAN WILL ONLY RUN 10-15 KNOTS...AND WILL TURN A
LITTLE MORE TO THE NORTHWEST. AGAIN WOULD EXPECT MOSTLY
FLURRIES...AND ONLY LOW CHANCES FOR LIGHT ACCUMULATIONS SOUTH OF A
LINE FROM HOWELL TO DETROIT.
POTENTIAL FOR LIGHT SNOW LOOKS A LITTLE BETTER ON SATURDAY AS A
SHORTWAVE TROUGH AXIS CLIPS ACROSS THE AREA. LAKE EFFECT ENHANCEMENT
ALSO LOOKS MORE LIKELY AS EQUILIBRIUM HEIGHTS OVER LAKE
MICHIGAN HIT THEIR PEAK AROUND 12KFT AND LAKE TO H850 DELTA T VALUES
RISE TO OVER 20 C. LIMITING FACTORS FOR THIS SIDE OF THE STATE ONCE
AGAIN WILL BE LIGHT FLOW AND WINDS TURNING MORE TO THE
NORTH-NORTHWEST. WOULD EXPECT FLURRIES AND SCATTERED LIGHT SNOW
SHOWERS ACROSS THE AREA IN THIS SET-UP...WITH BETTER POTENTIAL
(HIGHER POPS) SOUTH OF M-59 WHERE CONVERGENCE SHOULD BE BETTER.
LONGWAVE TROUGH WILL PUSH TO THE EAST COAST DURING THE SECOND HALF
OF THE WEEKEND...ALLOWING AN UPSTREAM RIDGE TO SLIDE IN OVERHEAD
SUNDAY INTO MONDAY. ENERGY DIVING OUT OF THE GULF OF ALASKA WILL
DROP THROUGH THE CENTRAL ROCKIES MONDAY...PULLING ADDITIONAL ENERGY
OUT OF THE SOUTHERN STREAM BEFORE IT BECOMES MORE ORGANIZED AND
DEEPENS OVER THE GREAT LAKES MONDAY NIGHT AND TUESDAY (AIDED BY GOOD
HEIGHT FALLS AND STRONG JET DYNAMICS). TRENDS WITH THE EURO AND GFS
HAVE BEEN TO SHIFT THIS SYSTEM FURTHER NORTH OVER THE PAST 24
HOURS...WITH A SURFACE LOW CENTER TRACK MORE ACROSS CENTRAL OR
NORTHERN MICHIGAN. GIVEN THAT THE GEM AND UKMET ARE STILL FURTHER
SOUTH WITH THE TRACK...MADE JUST MINOR ADJUSTMENTS TO PRECIPITATION
TYPE THIS FORECAST CYCLE TO INCREASE RAIN POTENTIAL. 14.12Z EURO/GFS
SOLUTIONS NOW SUPPORT ALL RAIN MONDAY NIGHT BEFORE A CHANGEOVER TO
SNOW BEHIND A STRONG COLD FRONT ON TUESDAY. ACCUMULATIONS STILL LOOK
POSSIBLE...BUT MAY BE DELAYED UNTIL TUESDAY.
MARINE...
LOW PRESSURE WILL TRACK THROUGH LOWER MICHIGAN THIS AFTERNOON AND
ACROSS NORTHERN LAKE HURON THIS EVENING. CURRENT SURFACE
OBSERVATIONS IN THE INCREASED GRADIENT PORTION OF THE SURFACE LOW IS
SUPPORTING WIND GUSTS OF UP TO 30 KNOTS. WITH NO EXPECTED
DEEPENING/ACTUAL MIDLEVEL WEAKENING RATES WILL CANCEL THE GALE WATCH
AND FORGO A GALE WARNING. THIS IS ALSO SUPPORTED BY THE VERY BRIEF
DURATION TIME. HOWEVER...WITH THE COLD NORTHWEST FLOW FOLLOWING THE
CYCLONE...DID ISSUE A BRISK WIND ADVISORY FOR ALL NEARSHORE ZONES.
WINDS WILL WEAKEN ON FRIDAY AS ARCTIC HIGH PRESSURE BUILDS INTO THE
WESTERN GREAT LAKES REGION. THIS HIGH WILL KEEP RELATIVELY LIGHT
WINDS ON THE LAKES THROUGH THE WEEKEND. A LOW PRESSURE SYSTEM IS
FORECAST TO INTENSIFY OVER THE GREAT LAKES REGION MONDAY NIGHT INTO
TUESDAY AND WILL OFFER THE NEXT CHANCE FOR STRONG WINDS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
BRISK WIND ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
HURON INCLUDING SAGINAW BAY...UNTIL 10 AM FRIDAY.
LAKE ST CLAIR...
BRISK WIND ADVISORY...UNTIL 4 AM FRIDAY.
MI WATERS OF LAKE ERIE...
BRISK WIND ADVISORY...UNTIL 4 AM FRIDAY.
&&
$$
AVIATION.....DG
SHORT TERM...CB
LONG TERM....HLO
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
412 PM CST FRI FEB 15 2013
.DISCUSSION...
Short Range (Tonight through Sunday)...
Main weather concern for this period centers on the overnight period
but confined to only the western third of the CWA. One last
vorticity max/shortwave diving down the backside of a retreating
broad upper trough will drop south-southeast across eastern NE
passing just west of the MO/KS state line overnight. Satellite
imagery and radar returns suggest two vorticity maxima...one moving
into northeast NE and a second west of BIE. Features are best seen
on NAM h7 prog. Scattered snow showers a bit more widespread than
shown by NAM output while RAP looks too generous on qpf. Prefer
blending the two model outputs which results in higher pops and
expanding snow shield a bit more east. Moderately high liquid/snow
ratios show potential for a narrow swath of 1+ inches of snow over
the far western counties. Given the expected scattered coverage of
the snow prefer keeping pops under the likely category for now. Snow
will have exited the southwestern CWA by Saturday morning with
clearing from north to south.
Saturday will bring the start of a welcome warmup over the Plains
which will quickly spread east...reaching into the western counties
by the afternoon hours. A band of dense mid level clouds will spread
from west to east Saturday night and herald the arrival of the
deepening warm air advection zone. Still expecting a significant
warmup on Sunday although there may be a tighter west to east
gradient due as boundary layer winds take on a south-southeast
direction which will limit the degree of warming further east.
MJ
Medium Range (Monday through Friday)...
Next week continues to look very active, with two systems moving
through the Plains on Monday night and again from Wednesday night
through early Friday. The primary focus will be the significant
system for Wednesday night through Thursday night, which has the
potential to be a fairly major winter storm if the current track
pans out.
On Monday, a deep longwave trough will dive through the Central
Plains, driving a surface cold front through the CWA during the
daylight hours. A broad area of scattered rain showers will be
possible along and ahead of the front, but amounts will be light as
moisture return into the Plains will be quite limited. A brief mix
with snow may be possible along our eastern border if any light
precipitation can linger behind the surface boundary, but no snow
accumulation is expected.
By Wednesday night, a deep upper low will begin to eject out of the
four corners region. As it moves eastward into the southern Plains,
strong southerly flow will draw Gulf moisture into the system, which
will combine with the existing Pacific moisture and enhance
precipitation coverage and intensity as the system begins to lift
northeast. All model solutions bring the elevated warm front into at
least the southeastern two thirds of the CWA by Thursday morning but
keep cold air lingering at the surface over almost the entirety of
the area, indicating a potential for freezing rain in those areas.
Since this is a deviation from previous forecasts, have started out
with a slight chance for freezing rain on top of the primary
rain/snow mix, but the probability for ice may need to be heightened
if future forecasts look similar. As cold air wraps in behind the
850mb low, precipitation should change to all snow from west to east
during the day on Thursday, becoming all snow and lifting out of the
area after 00z Friday. Very preliminary snowfall totals range from
more than 6 inches across the northern third of the forecast area
where precipitation type is likely to be snow during the majority of
the event, to 2-3 inches in west central and eastern parts of the
CWA, then tapering to less than 2 inches in the far southwest where
rain or freezing rain will be the predominant precipitation type
during the majority of the event.
With the consistency of model solutions, both temporally and between
different model configurations, the overall potential for a winter
storm is increasing. However, precipitation types and snowfall
amounts are still somewhat uncertain and will need to be further
refined, especially as this system heads onshore early next week.
Laflin
&&
.AVIATION...
For the 18z TAF...VFR conditions will continue into early this
evening although mid level cigs will move in around sunset in
advance of an approaching vorticity maxima. Satellite imagery
suggests this feature is loosely held together as it moves into
northeast NE. System is best modeled at 700mb with the NAM tracking
the center across eastern KS tonight. Narrow swath of snow expected
to fall close the the vorticity center. Low confidence on
accumulating snow reaching the terminals so have improved
visibilities and raised cigs to high end MVFR. Better bet for lower
cigs/vsbys and snow will be over eastern KS. Looks like a 3-5 hour
window for snow threat.
MVFR cigs will improve to VFR Saturday morning as winds back from
north to west indicating warm air advection process beginning.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1122 AM CST FRI FEB 15 2013
.UPDATE...
ISSUED AT 919 AM CST FRI FEB 15 2013
UPDATED FORECAST TO REMOVE FLURRIES AND CLEAR SKIES FOR TODAY.
CVKING
&&
.SHORT TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TODAY)
EARLY MORNING RUC ANALYSES OF THE 1.5 PVU SFC COMBINED WITH WATER
VAPOR IMAGERY DEPICTED A REASONABLY STRONG PV ANOMALY MOVING ACROSS
NRN MO. THIS FEATURE IS EXPECTED TO CONTINUE MOVING ACROSS THE AREA
TODAY WITHIN A BROADER PATTN OF NW FLOW ALOFT. DESPITE THE PRESENCE
OF A FORCING MECHANISM...THE LIMITING FACTOR FOR MEASURABLE PCPN
TODAY WILL BE MOISTURE GIVEN THE FAIRLY DRY LOW AND MID LEVELS AS
WELL AS DECREASING PW VALUES THROUGH THE DAY. AT THE SFC...A CDFNT
WAS LOCATED FM CENTRAL KS THROUGH NRN MO INTO NRN IL AT 06Z. THIS
FRONT WILL CONTINUE MOVING SEWD TODAY...LEADING TO A COMPLICATED
FCST OF TEMPERATURE TRENDS DUE TO THE COMPETING FACTORS OF LOW LEVEL
CAA...POTENTIAL MIXING ABOVE 900 MB...AND THE EFFECTS OF POSTFRONTAL
CLOUDINESS DURING THE LATE MORNING FOLLOWED BY ADDITIONAL CLOUDS
ADVECTING SWD DURING THE LATE AFTN.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TONIGHT THROUGH SUNDAY)
SHORT RANGE MODELS ARE MAINTAINING GOOD RUN TO RUN CONTINUITY
WITH SYNOPTIC FEATURES HEADING INTO THE WEEKEND. ANOTHER SHORTWAVE
WILL DROP SOUTH ACROSS THE PLAINS TONIGHT ON THE BACK SIDE OF THE
UPPER LEVEL TROF...BRINGING A REINFORCING SHOT OF COLD AIR TO THE
AREA FOR SATURDAY. DYNAMICS WITH THIS FEATURE SHOULD CONFINE ANY
PRECIP THREAT TO THE WEST OF OUR CWA...BUT WITH DIRTY NW FLOW AND
MEAN TROF AXIS REMAINING PARKED OVER AREA WE SHOULD CERTAINLY SEE
SOME CLOUDINESS OVERNIGHT AND AT LEAST INTO SATURDAY MORNING.
TEMPERATURE TRENDS IN GOING FORECAST STILL LOOK PRETTY GOOD. THIS
AMS IS FAIRLY CHILLY BUT DUE TO THE EXPECTED CLOUDS OVERNIGHT I HAVE
FOUGHT THE TEMPTATION TO GO TOO COLD...AND STILL HAVE LOWS IN THE
UPPER TEENS TO LOWER 20S. HIGHS SHOULD REBOUND INTO THE L-M30S ON
SATURDAY.
TROF IS STILL ON SCHEDULE TO SWING INTO THE EASTERN U.S. ON SUNDAY.
THIS WILL ALLOW A RAPID TEMPERATURE MODERATION OVER THE CWA...
WITH HIGHS RANGING FROM THE MID 40S OVER OUR E COUNTIES...TO THE
MID 50S OVER MID MO.
(MONDAY-THURSDAY)
ITS PROBABLY A BIT OF AN UNDERSTATEMENT TO SAY THAT THE UA PATTERN
OVER THE CONUS WILL BE ACTIVE FOR MUCH OF NEXT WEEK...WITH THE VERY
AMPLIFIED AND PROGRESSIVE PATTERN PROGGED TO BRING TWO STORM
SYSTEMS INTO THE CENTRAL U.S. MEDIUM RANGE SOLUTIONS ARE
REMAINING IN REMARKABLE RUN TO RUN AND MODEL TO MODEL AGREEMENT
WITH THE TIMING OF THESE SYSTEMS...WITH THE FIRST IMPACTING THE
REGION ON MONDAY AND MONDAY NIGHT AND THE SECOND...AND PROBABLY
STRONGER...SYSTEM ARRIVING LATE WEDNESDAY AND THURSDAY.
MONDAY AND MONDAY NIGHT`S SYSTEM WILL PRIMARILY BE A RAIN
EVENT...WITH THE BULK OF THE PRECIP SHUTTING DOWN ON MONDAY NIGHT
WITH THE ARRIVAL OF THE COLD AIR PREVENTING ANY SIGNIFICANT PERIOD
OF SNOWFALL. SOLUTIONS HAVE NOT BACKED OFF OF THE THINKING THAT
MOISTURE ADVECTION IN ADVANCE OF THE SYSTEM AND DYNAMICS WILL BE
STRONG...SO LIKELY POPS OVER MOST OF THE CWA STILL LOOK LIKE A GOOD
CALL.
ANOTHER SHOT OF COLD AIR IN THE WAKE OF MONDAY`S SYSTEM WILL DROP
TEMPS BACK TO BELOW AVERAGE LEVELS FOR TUESDAY AND WEDNESDAY...AND
THIS COLD AIR WILL SET THE STAGE FOR THE BIG QUESTION MARK FOR
THURSDAY`S SYSTEM...WHICH IS PTYPE. IT CERTAINLY APPEARS THAT THE
FIRST SHOT OF PRECIP INTO THE AREA LATE WEDNESDAY NIGHT AND THURSDAY
MORNING ASSOCIATED WITH INITIAL SURGE OF WARM ADVECTION WILL LIKELY
BE SNOW...BUT PRIMARY QUESTION IS WHAT PTYPES WILL DO DURING THE DAY
ON THURSDAY. OPERATIONAL GFS AND ECMWF ARE BOTH PROGGING VERY
STRONG 850 WAA INTO THE CWA BUT 850 TEMPS...ON BOTH SOLUTIONS...
APPEAR TO BE VERY RELUCTANT TO WARM DURING THE DAY. THIS TREND
LOOKS TO BE TOO COLD GIVEN PLACEMENT OF 850 LOW AND STRENGTH OF
WAA....BUT IT IS PROBABLY A STRONG SIGNAL THAT BOTH MODELS ARE
SUGGESTING THAT THE EVAPORATIVE COOLING THAT DEVELOPS WITH THE
ONSET OF PRECIP WILL BE TOUGH TO OVERCOME.
IF THE CONSENSUS OF THESE SOLUTIONS AND THE LATEST GFS ENSEMBLE
VERIFY...PTYPE WOULD BE ALL SNOW IN THE FAR NORTH AND ALL RAIN IN
THE FAR SOUTH...BUT OVER MOST OF THE CWA PTYPE COULD GO EITHER
WAY. AS MENTIONED BY THE DAY SHIFT YESTERDAY PTYPE FORECASTS WILL
LIKELY BE CHANGING SEVERAL TIMES AS THE EVENT GETS CLOSER IN
TIME...AND SINCE THE STORM IS STILL 7 DAYS OUT WILL MAINTAIN A
BROAD BRUSH APPROACH FOR PTYPE.
TRUETT
&&
.AVIATION...
ISSUED AT 1112 AM CST FRI FEB 15 2013
VFR CONDITIONS ARE EXPECTED. THE NEXT UPPER LEVEL DISTURBANCE
DROPPING SOUTHEAST FROM EASTERN NEBRASKA AND SOUTH DAKOTA WILL
BRING A PERIOD OF MOSTLY MID LEVEL CLOUDS TO THE REGION THIS
EVENING AND EARLY SATURDAY MORNING. UPSTREAM OBSERVATIONS SHOWS A
SMALL AREA OF MVFR CEILINGS AT THE CORE OF THE SYSTEM...WITH EVEN
A FEW FLURRIES. MODELS SUGGEST THAT ANY CHANCE OF MEASURABLE SNOW
AND LOWER CEILINGS WILL REMAIN WEST OF THE CWA. FAST UPPER LEVEL
FLOW WILL MEAN SKIES WILL CLEAR FROM THE NORTHWEST BY DAYBREAK
ACROSS THE CWA. WIND WILL REMAIN NORTHWEST AROUND 10KT.
SPECIFICS FOR KSTL...
VFR CONDITIONS WITH A PERIOD OF MID CLOUDS THIS EVENING. WIND
REMAINS NORTHWEST AROUND 10KT.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
921 AM CST FRI FEB 15 2013
.UPDATE...
ISSUED AT 919 AM CST FRI FEB 15 2013
UPDATED FORECAST TO REMOVE FLURRIES AND CLEAR SKIES FOR TODAY.
CVKING
&&
.SHORT TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TODAY)
EARLY MORNING RUC ANALYSES OF THE 1.5 PVU SFC COMBINED WITH WATER
VAPOR IMAGERY DEPICTED A REASONABLY STRONG PV ANOMALY MOVING ACROSS
NRN MO. THIS FEATURE IS EXPECTED TO CONTINUE MOVING ACROSS THE AREA
TODAY WITHIN A BROADER PATTN OF NW FLOW ALOFT. DESPITE THE PRESENCE
OF A FORCING MECHANISM...THE LIMITING FACTOR FOR MEASURABLE PCPN
TODAY WILL BE MOISTURE GIVEN THE FAIRLY DRY LOW AND MID LEVELS AS
WELL AS DECREASING PW VALUES THROUGH THE DAY. AT THE SFC...A CDFNT
WAS LOCATED FM CENTRAL KS THROUGH NRN MO INTO NRN IL AT 06Z. THIS
FRONT WILL CONTINUE MOVING SEWD TODAY...LEADING TO A COMPLICATED
FCST OF TEMPERATURE TRENDS DUE TO THE COMPETING FACTORS OF LOW LEVEL
CAA...POTENTIAL MIXING ABOVE 900 MB...AND THE EFFECTS OF POSTFRONTAL
CLOUDINESS DURING THE LATE MORNING FOLLOWED BY ADDITIONAL CLOUDS
ADVECTING SWD DURING THE LATE AFTN.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TONIGHT THROUGH SUNDAY)
SHORT RANGE MODELS ARE MAINTAINING GOOD RUN TO RUN CONTINUITY
WITH SYNOPTIC FEATURES HEADING INTO THE WEEKEND. ANOTHER SHORTWAVE
WILL DROP SOUTH ACROSS THE PLAINS TONIGHT ON THE BACK SIDE OF THE
UPPER LEVEL TROF...BRINGING A REINFORCING SHOT OF COLD AIR TO THE
AREA FOR SATURDAY. DYNAMICS WITH THIS FEATURE SHOULD CONFINE ANY
PRECIP THREAT TO THE WEST OF OUR CWA...BUT WITH DIRTY NW FLOW AND
MEAN TROF AXIS REMAINING PARKED OVER AREA WE SHOULD CERTAINLY SEE
SOME CLOUDINESS OVERNIGHT AND AT LEAST INTO SATURDAY MORNING.
TEMPERATURE TRENDS IN GOING FORECAST STILL LOOK PRETTY GOOD. THIS
AMS IS FAIRLY CHILLY BUT DUE TO THE EXPECTED CLOUDS OVERNIGHT I HAVE
FOUGHT THE TEMPTATION TO GO TOO COLD...AND STILL HAVE LOWS IN THE
UPPER TEENS TO LOWER 20S. HIGHS SHOULD REBOUND INTO THE L-M30S ON
SATURDAY.
TROF IS STILL ON SCHEDULE TO SWING INTO THE EASTERN U.S. ON SUNDAY.
THIS WILL ALLOW A RAPID TEMPERATURE MODERATION OVER THE CWA...
WITH HIGHS RANGING FROM THE MID 40S OVER OUR E COUNTIES...TO THE
MID 50S OVER MID MO.
(MONDAY-THURSDAY)
ITS PROBABLY A BIT OF AN UNDERSTATEMENT TO SAY THAT THE UA PATTERN
OVER THE CONUS WILL BE ACTIVE FOR MUCH OF NEXT WEEK...WITH THE VERY
AMPLIFIED AND PROGRESSIVE PATTERN PROGGED TO BRING TWO STORM
SYSTEMS INTO THE CENTRAL U.S. MEDIUM RANGE SOLUTIONS ARE
REMAINING IN REMARKABLE RUN TO RUN AND MODEL TO MODEL AGREEMENT
WITH THE TIMING OF THESE SYSTEMS...WITH THE FIRST IMPACTING THE
REGION ON MONDAY AND MONDAY NIGHT AND THE SECOND...AND PROBABLY
STRONGER...SYSTEM ARRIVING LATE WEDNESDAY AND THURSDAY.
MONDAY AND MONDAY NIGHT`S SYSTEM WILL PRIMARILY BE A RAIN
EVENT...WITH THE BULK OF THE PRECIP SHUTTING DOWN ON MONDAY NIGHT
WITH THE ARRIVAL OF THE COLD AIR PREVENTING ANY SIGNIFICANT PERIOD
OF SNOWFALL. SOLUTIONS HAVE NOT BACKED OFF OF THE THINKING THAT
MOISTURE ADVECTION IN ADVANCE OF THE SYSTEM AND DYNAMICS WILL BE
STRONG...SO LIKELY POPS OVER MOST OF THE CWA STILL LOOK LIKE A GOOD
CALL.
ANOTHER SHOT OF COLD AIR IN THE WAKE OF MONDAY`S SYSTEM WILL DROP
TEMPS BACK TO BELOW AVERAGE LEVELS FOR TUESDAY AND WEDNESDAY...AND
THIS COLD AIR WILL SET THE STAGE FOR THE BIG QUESTION MARK FOR
THURSDAY`S SYSTEM...WHICH IS PTYPE. IT CERTAINLY APPEARS THAT THE
FIRST SHOT OF PRECIP INTO THE AREA LATE WEDNESDAY NIGHT AND THURSDAY
MORNING ASSOCIATED WITH INITIAL SURGE OF WARM ADVECTION WILL LIKELY
BE SNOW...BUT PRIMARY QUESTION IS WHAT PTYPES WILL DO DURING THE DAY
ON THURSDAY. OPERATIONAL GFS AND ECMWF ARE BOTH PROGGING VERY
STRONG 850 WAA INTO THE CWA BUT 850 TEMPS...ON BOTH SOLUTIONS...
APPEAR TO BE VERY RELUCTANT TO WARM DURING THE DAY. THIS TREND
LOOKS TO BE TOO COLD GIVEN PLACEMENT OF 850 LOW AND STRENGTH OF
WAA....BUT IT IS PROBABLY A STRONG SIGNAL THAT BOTH MODELS ARE
SUGGESTING THAT THE EVAPORATIVE COOLING THAT DEVELOPS WITH THE
ONSET OF PRECIP WILL BE TOUGH TO OVERCOME.
IF THE CONSENSUS OF THESE SOLUTIONS AND THE LATEST GFS ENSEMBLE
VERIFY...PTYPE WOULD BE ALL SNOW IN THE FAR NORTH AND ALL RAIN IN
THE FAR SOUTH...BUT OVER MOST OF THE CWA PTYPE COULD GO EITHER
WAY. AS MENTIONED BY THE DAY SHIFT YESTERDAY PTYPE FORECASTS WILL
LIKELY BE CHANGING SEVERAL TIMES AS THE EVENT GETS CLOSER IN
TIME...AND SINCE THE STORM IS STILL 7 DAYS OUT WILL MAINTAIN A
BROAD BRUSH APPROACH FOR PTYPE.
TRUETT
&&
.AVIATION...
ISSUED AT 548 AM CST FRI FEB 15 2013
SCT-BKN MVFR CLOUDS INVOF A CDFNT SHOULD MOVE SOUTH AND EAST OF
THE TERMINALS THIS MORNING. SCT FLURRIES ARE POSSIBLE HOWEVER NO
VIS RESTRICTIONS ARE ANTICIPATED. WINDS WILL REMAIN NWLY THROUGH
THE PD. ADDITIONAL CLOUDS SHOULD REDEVELOP TONIGHT AHEAD OF AN
APPROACHING UPPER LEVEL DISTURBANCE HOWEVER IT APPEARS THAT CIGS
WILL REMAIN VFR TONIGHT DUE TO LIMITED MOISTURE IN THE ATMOSPHERE.
SPECIFICS FOR KSTL...SCT-BKN MVFR CLOUDS INVOF A CDFNT SHOULD MOVE
SOUTH AND EAST OF KSTL THIS MORNING. SCT FLURRIES ARE POSSIBLE
HOWEVER NO VIS RESTRICTIONS ARE ANTICIPATED. WINDS WILL REMAIN
NWLY THROUGH THE PD.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
609 AM CST FRI FEB 15 2013
.SHORT TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TODAY)
EARLY MORNING RUC ANALYSES OF THE 1.5 PVU SFC COMBINED WITH WATER
VAPOR IMAGERY DEPICTED A REASONABLY STRONG PV ANOMALY MOVING ACROSS
NRN MO. THIS FEATURE IS EXPECTED TO CONTINUE MOVING ACROSS THE AREA
TODAY WITHIN A BROADER PATTN OF NW FLOW ALOFT. DESPITE THE PRESENCE
OF A FORCING MECHANISM...THE LIMITING FACTOR FOR MEASURABLE PCPN
TODAY WILL BE MOISTURE GIVEN THE FAIRLY DRY LOW AND MID LEVELS AS
WELL AS DECREASING PW VALUES THROUGH THE DAY. AT THE SFC...A CDFNT
WAS LOCATED FM CENTRAL KS THROUGH NRN MO INTO NRN IL AT 06Z. THIS
FRONT WILL CONTINUE MOVING SEWD TODAY...LEADING TO A COMPLICATED
FCST OF TEMPERATURE TRENDS DUE TO THE COMPETING FACTORS OF LOW LEVEL
CAA...POTENTIAL MIXING ABOVE 900 MB...AND THE EFFECTS OF POSTFRONTAL
CLOUDINESS DURING THE LATE MORNING FOLLOWED BY ADDITIONAL CLOUDS
ADVECTING SWD DURING THE LATE AFTN.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TONIGHT THROUGH SUNDAY)
SHORT RANGE MODELS ARE MAINTAINING GOOD RUN TO RUN CONTINUITY
WITH SYNOPTIC FEATURES HEADING INTO THE WEEKEND. ANOTHER SHORTWAVE
WILL DROP SOUTH ACROSS THE PLAINS TONIGHT ON THE BACK SIDE OF THE
UPPER LEVEL TROF...BRINGING A REINFORCING SHOT OF COLD AIR TO THE
AREA FOR SATURDAY. DYNAMICS WITH THIS FEATURE SHOULD CONFINE ANY
PRECIP THREAT TO THE WEST OF OUR CWA...BUT WITH DIRTY NW FLOW AND
MEAN TROF AXIS REMAINING PARKED OVER AREA WE SHOULD CERTAINLY SEE
SOME CLOUDINESS OVERNIGHT AND AT LEAST INTO SATURDAY MORNING.
TEMPERATURE TRENDS IN GOING FORECAST STILL LOOK PRETTY GOOD. THIS
AMS IS FAIRLY CHILLY BUT DUE TO THE EXPECTED CLOUDS OVERNIGHT I HAVE
FOUGHT THE TEMPTATION TO GO TOO COLD...AND STILL HAVE LOWS IN THE
UPPER TEENS TO LOWER 20S. HIGHS SHOULD REBOUND INTO THE L-M30S ON
SATURDAY.
TROF IS STILL ON SCHEDULE TO SWING INTO THE EASTERN U.S. ON SUNDAY.
THIS WILL ALLOW A RAPID TEMPERATURE MODERATION OVER THE CWA...
WITH HIGHS RANGING FROM THE MID 40S OVER OUR E COUNTIES...TO THE
MID 50S OVER MID MO.
(MONDAY-THURSDAY)
ITS PROBABLY A BIT OF AN UNDERSTATEMENT TO SAY THAT THE UA PATTERN
OVER THE CONUS WILL BE ACTIVE FOR MUCH OF NEXT WEEK...WITH THE VERY
AMPLIFIED AND PROGRESSIVE PATTERN PROGGED TO BRING TWO STORM
SYSTEMS INTO THE CENTRAL U.S. MEDIUM RANGE SOLUTIONS ARE
REMAINING IN REMARKABLE RUN TO RUN AND MODEL TO MODEL AGREEMENT
WITH THE TIMING OF THESE SYSTEMS...WITH THE FIRST IMPACTING THE
REGION ON MONDAY AND MONDAY NIGHT AND THE SECOND...AND PROBABLY
STRONGER...SYSTEM ARRIVING LATE WEDNESDAY AND THURSDAY.
MONDAY AND MONDAY NIGHT`S SYSTEM WILL PRIMARILY BE A RAIN
EVENT...WITH THE BULK OF THE PRECIP SHUTTING DOWN ON MONDAY NIGHT
WITH THE ARRIVAL OF THE COLD AIR PREVENTING ANY SIGNIFICANT PERIOD
OF SNOWFALL. SOLUTIONS HAVE NOT BACKED OFF OF THE THINKING THAT
MOISTURE ADVECTION IN ADVANCE OF THE SYSTEM AND DYNAMICS WILL BE
STRONG...SO LIKELY POPS OVER MOST OF THE CWA STILL LOOK LIKE A GOOD
CALL.
ANOTHER SHOT OF COLD AIR IN THE WAKE OF MONDAY`S SYSTEM WILL DROP
TEMPS BACK TO BELOW AVERAGE LEVELS FOR TUESDAY AND WEDNESDAY...AND
THIS COLD AIR WILL SET THE STAGE FOR THE BIG QUESTION MARK FOR
THURSDAY`S SYSTEM...WHICH IS PTYPE. IT CERTAINLY APPEARS THAT THE
FIRST SHOT OF PRECIP INTO THE AREA LATE WEDNESDAY NIGHT AND THURSDAY
MORNING ASSOCIATED WITH INITIAL SURGE OF WARM ADVECTION WILL LIKELY
BE SNOW...BUT PRIMARY QUESTION IS WHAT PTYPES WILL DO DURING THE DAY
ON THURSDAY. OPERATIONAL GFS AND ECMWF ARE BOTH PROGGING VERY
STRONG 850 WAA INTO THE CWA BUT 850 TEMPS...ON BOTH SOLUTIONS...
APPEAR TO BE VERY RELUCTANT TO WARM DURING THE DAY. THIS TREND
LOOKS TO BE TOO COLD GIVEN PLACEMENT OF 850 LOW AND STRENGTH OF
WAA....BUT IT IS PROBABLY A STRONG SIGNAL THAT BOTH MODELS ARE
SUGGESTING THAT THE EVAPORATIVE COOLING THAT DEVELOPS WITH THE
ONSET OF PRECIP WILL BE TOUGH TO OVERCOME.
IF THE CONSENSUS OF THESE SOLUTIONS AND THE LATEST GFS ENSEMBLE
VERIFY...PTYPE WOULD BE ALL SNOW IN THE FAR NORTH AND ALL RAIN IN
THE FAR SOUTH...BUT OVER MOST OF THE CWA PTYPE COULD GO EITHER
WAY. AS MENTIONED BY THE DAY SHIFT YESTERDAY PTYPE FORECASTS WILL
LIKELY BE CHANGING SEVERAL TIMES AS THE EVENT GETS CLOSER IN
TIME...AND SINCE THE STORM IS STILL 7 DAYS OUT WILL MAINTAIN A
BROAD BRUSH APPROACH FOR PTYPE.
TRUETT
&&
.AVIATION...
ISSUED AT 548 AM CST FRI FEB 15 2013
SCT-BKN MVFR CLOUDS INVOF A CDFNT SHOULD MOVE SOUTH AND EAST OF
THE TERMINALS THIS MORNING. SCT FLURRIES ARE POSSIBLE HOWEVER NO
VIS RESTRICTIONS ARE ANTICIPATED. WINDS WILL REMAIN NWLY THROUGH
THE PD. ADDITIONAL CLOUDS SHOULD REDEVELOP TONIGHT AHEAD OF AN
APPROACHING UPPER LEVEL DISTURBANCE HOWEVER IT APPEARS THAT CIGS
WILL REMAIN VFR TONIGHT DUE TO LIMITED MOISTURE IN THE ATMOSPHERE.
SPECIFICS FOR KSTL...SCT-BKN MVFR CLOUDS INVOF A CDFNT SHOULD MOVE
SOUTH AND EAST OF KSTL THIS MORNING. SCT FLURRIES ARE POSSIBLE
HOWEVER NO VIS RESTRICTIONS ARE ANTICIPATED. WINDS WILL REMAIN
NWLY THROUGH THE PD.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
316 AM CST FRI FEB 15 2013
.SHORT TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TODAY)
EARLY MORNING RUC ANALYSES OF THE 1.5 PVU SFC COMBINED WITH WATER
VAPOR IMAGERY DEPICTED A REASONABLY STRONG PV ANOMALY MOVING ACROSS
NRN MO. THIS FEATURE IS EXPECTED TO CONTINUE MOVING ACROSS THE AREA
TODAY WITHIN A BROADER PATTN OF NW FLOW ALOFT. DESPITE THE PRESENCE
OF A FORCING MECHANISM...THE LIMITING FACTOR FOR MEASURABLE PCPN
TODAY WILL BE MOISTURE GIVEN THE FAIRLY DRY LOW AND MID LEVELS AS
WELL AS DECREASING PW VALUES THROUGH THE DAY. AT THE SFC...A CDFNT
WAS LOCATED FM CENTRAL KS THROUGH NRN MO INTO NRN IL AT 06Z. THIS
FRONT WILL CONTINUE MOVING SEWD TODAY...LEADING TO A COMPLICATED
FCST OF TEMERATURE TRENDS DUE TO THE COMPETING FACTORS OF LOW LEVEL
CAA...POTENTIAL MIXING ABOVE 900 MB...AND THE EFFECTS OF POSTFRONTAL
CLOUDINESS DURING THE LATE MORNING FOLLOWED BY ADDITIONAL CLOUDS
ADVECTING SWD DURING THE LATE AFTN.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 303 AM CST FRI FEB 15 2013
(TONIGHT THROUGH SUNDAY)
SHORT RANGE MODELS ARE MAINTAINING GOOD RUN TO RUN CONTINUITY
WITH SYNOPTIC FEATURES HEADING INTO THE WEEKEND. ANOTHER SHORTWAVE
WILL DROP SOUTH ACROSS THE PLAINS TONIGHT ON THE BACK SIDE OF THE
UPPER LEVEL TROF...BRINGING A REINFORCING SHOT OF COLD AIR TO THE
AREA FOR SATURDAY. DYNAMICS WITH THIS FEATURE SHOULD CONFINE ANY
PRECIP THREAT TO THE WEST OF OUR CWA...BUT WITH DIRTY NW FLOW AND
MEAN TROF AXIS REMAINING PARKED OVER AREA WE SHOULD CERTAINLY SEE
SOME CLOUDINESS OVERNIGHT AND AT LEAST INTO SATURDAY MORNING.
TEMPERATURE TRENDS IN GOING FORECAST STILL LOOK PRETTY GOOD. THIS
AMS IS FAIRLY CHILLY BUT DUE TO THE EXPECTED CLOUDS OVERNIGHT I HAVE
FOUGHT THE TEMPTATION TO GO TOO COLD...AND STILL HAVE LOWS IN THE
UPPER TEENS TO LOWER 20S. HIGHS SHOULD REBOUND INTO THE L-M30S ON
SATURDAY.
TROF IS STILL ON SCHEDULE TO SWING INTO THE EASTERN U.S. ON SUNDAY.
THIS WILL ALLOW A RAPID TEMPERATURE MODERATION OVER THE CWA...
WITH HIGHS RANGING FROM THE MID 40S OVER OUR E COUNTIES...TO THE
MID 50S OVER MID MO.
(MONDAY-THURSDAY)
ITS PROBABLY A BIT OF AN UNDERSTATEMENT TO SAY THAT THE UA PATTERN
OVER THE CONUS WILL BE ACTIVE FOR MUCH OF NEXT WEEK...WITH THE VERY
AMPLIFIED AND PROGRESSIVE PATTERN PROGGED TO BRING TWO STORM
SYSTEMS INTO THE CENTRAL U.S. MEDIUM RANGE SOLUTIONS ARE
REMAINING IN REMARKABLE RUN TO RUN AND MODEL TO MODEL AGREEMENT
WITH THE TIMING OF THESE SYSTEMS...WITH THE FIRST IMPACTING THE
REGION ON MONDAY AND MONDAY NIGHT AND THE SECOND...AND PROBABLY
STRONGER...SYSTEM ARRIVING LATE WEDNESDAY AND THURSDAY.
MONDAY AND MONDAY NIGHT`S SYSTEM WILL PRIMARILY BE A RAIN
EVENT...WITH THE BULK OF THE PRECIP SHUTTING DOWN ON MONDAY NIGHT
WITH THE ARRIVAL OF THE COLD AIR PREVENTING ANY SIGNIFICANT PERIOD
OF SNOWFALL. SOLUTIONS HAVE NOT BACKED OFF OF THE THINKING THAT
MOISTURE ADVECTION IN ADVANCE OF THE SYSTEM AND DYNAMICS WILL BE
STRONG...SO LIKELY POPS OVER MOST OF THE CWA STILL LOOK LIKE A GOOD
CALL.
ANOTHER SHOT OF COLD AIR IN THE WAKE OF MONDAY`S SYSTEM WILL DROP
TEMPS BACK TO BELOW AVERAGE LEVELS FOR TUESDAY AND WEDNESDAY...AND
THIS COLD AIR WILL SET THE STAGE FOR THE BIG QUESTION MARK FOR
THURSDAY`S SYSTEM...WHICH IS PTYPE. IT CERTAINLY APPEARS THAT THE
FIRST SHOT OF PRECIP INTO THE AREA LATE WEDNESDAY NIGHT AND THURSDAY
MORNING ASSOCIATED WITH INITIAL SURGE OF WARM ADVECTION WILL LIKELY
BE SNOW...BUT PRIMARY QUESTION IS WHAT PTYPES WILL DO DURING THE DAY
ON THURSDAY. OPERATIONAL GFS AND ECMWF ARE BOTH PROGGING VERY
STRONG 850 WAA INTO THE CWA BUT 850 TEMPS...ON BOTH SOLUTIONS...
APPEAR TO BE VERY RELUCTANT TO WARM DURING THE DAY. THIS TREND
LOOKS TO BE TOO COLD GIVEN PLACEMENT OF 850 LOW AND STRENGTH OF
WAA....BUT IT IS PROBABLY A STRONG SIGNAL THAT BOTH MODELS ARE
SUGGESTING THAT THE EVAPORATIVE COOLING THAT DEVELOPS WITH THE
ONSET OF PRECIP WILL BE TOUGH TO OVERCOME.
IF THE CONSENSUS OF THESE SOLUTIONS AND THE LATEST GFS ENSEMBLE
VERIFY...PTYPE WOULD BE ALL SNOW IN THE FAR NORTH AND ALL RAIN IN
THE FAR SOUTH...BUT OVER MOST OF THE CWA PTYPE COULD GO EITHER
WAY. AS MENTIONED BY THE DAY SHIFT YESTERDAY PTYPE FORECASTS WILL
LIKELY BE CHANGING SEVERAL TIMES AS THE EVENT GETS CLOSER IN
TIME...AND SINCE THE STORM IS STILL 7 DAYS OUT WILL MAINTAIN A
BROAD BRUSH APPROACH FOR PTYPE.
TRUETT
&&
.AVIATION...
ISSUED AT 1045 PM CST THU FEB 14 2013
WEAK UPPER LEVEL DISTURBANCE OVER N CNTRL MO WILL DROP SEWD
THROUGH OUR AREA LATE TGT BRINGING LOW-MID LEVEL CLOUD COVER...
POSSIBLY BRIEFLY DOWN TO THE MVFR CATAGORY ALONG WITH A BRIEF
PERIOD OF LIGHT SNOW OR FLURRIES. AT THIS TIME IT LOOKS LIKE THE
LIGHT SNOW WILL BE PATCHY...SO WILL ONLY INCLUDE TEMPO GROUPS FOR
LIGHT SNOW OR FLURRIES IN THE TAFS LATE TGT INTO EARLY FRI MRNG.
ANY LIGHT PRECIPITATION WILL MOVE OUT OF UIN BY 09Z FRI AND THE
REST OF THE TAF SITES EARLY FRI MRNG WHILE THE LOW-MID LEVEL CLOUD
CEILING SCATTERS OUT AS COLD...DRY AIR FILTERS SEWD INTO THE
REGION. NWLY SFC WINDS WILL STRENGTHEN LATE TGT AFTER THE PASSAGE
OF A SECONDARY REINFORCING COLD FRONT. THESE NWLY SFC WINDS WILL
CONTINUE ON FRI AND FRI EVNG.
SPECIFICS FOR KSTL...THE CLOUD CEILING WILL LOWER LATE TGT WITH A
BRIEF PERIOD OF LIGHT SNOW OR FLURRIES POSSIBLE LATE TGT AND
EARLY FRI MRNG. MOST OF THIS SNOW SHOULD BE IN THE FORM OF
FLURRIES WITH UNRESTRICTED VSBSYS...BUT THERE COULD BE A BRIEF
PERIOD OF LIGHT SNOW OR SNOW SHOWERS DROPPING THE VSBY TO AROUND
5-6SM. THE CEILING MAY BRIEFLY LOWER TO AROUND 2000-3000 FT AT OR
JUST BEFORE 12Z FRI THEN SCATTER OUT LATER FRI MRNG. NWLY SFC
WINDS SHOULD STRENGTHEN LATE TGT AND FRI MRNG TO AROUND 12 KTS...
THEN WEAKEN LATE FRI AFTN AND EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
834 PM MST SAT FEB 16 2013
.SHORT TERM...VALID FOR SUN AND MON...
EVENING MOISTURE CHANNEL IMAGERY SHOWS THE AXIS OF A VIGOROUS MID-
LEVEL SHORT WAVE TROUGH CROSSING CENTRAL WA AND OR...WITH A RATHER
NICE PLUME OF HIGH-LEVEL PACIFIC MOISTURE AHEAD OF ITS DYNAMICS. A
BROAD AREA OF DOWNSTREAM AND LEE-SIDE SURFACE PRESSURE FALLS IS IN
PLACE...AND HAS ENABLED INCREASING GAP-AIDED WINDS FOR LIVINGSTON.
OUR WIND ADVISORY IS THUS ON TRACK. FORECAST SOUNDINGS SUGGEST THE
MID-LEVEL STABILITY NECESSARY FOR GAP WINDS WILL ERODE AS THE COLD
FRONT APPROACHES BY 12 UTC...SO THE ADVISORY MAY BE CANCELLED JUST
A BIT EARLY /PERHAPS EVEN WITH THE 4 AM MST FORECAST PACKAGE/.
AS FAR AS THE OVERNIGHT FORECAST GOES...WE BLENDED LOWS WITH A MIX
OF RECENT RAP AND LAMP MOS GUIDANCE. THAT MEANT RAISING LOWS FOR A
LARGE PART OF THE AREA...EXCEPT IN SOME VALLEYS LIKE AROUND BAKER.
THERE IS ENOUGH DRY AIR AND A WEAKNESS IN LOW-LEVEL FLOW FOR US TO
BUY INTO SOME DECENT RADIATIONAL COOLING THERE. OTHERWISE...WE ARE
ADVERTISING INCREASING PRECIPITATION CHANCES OVER SOUTH CENTRAL MT
IN THE 06 TO 12 UTC TIME FRAME...AND THAT SHOULD BE A GOOD CALL AS
500-300 HPA Q-VECTOR FORCING RAMPS UP. PLUS...THE PLUME OF PACIFIC
MOISTURE OBSERVED THIS EVENING AHEAD OF THE WAVE CERTAINLY MAKES A
CASE FOR POPS...THOUGH DOWNSLOPE LOW-LEVEL FLOW COULD KEEP MUCH OF
ANY SHOWER ACTIVITY FOCUSED OVER THE MOUNTAINS OVERNIGHT. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MINOR CHANGES TO GOING FORECAST...BUT A PRETTY BIG CHANGE IN
CONSISTENCY BETWEEN MODELS WITH THE 12Z RUN. LATEST MODELS IN GOOD
AGREEMENT BRINGING UPPER LOW DOWN INTO CALIFORNIA ON TUESDAY THEN
UP INTO SOUTHERN COLORADO WEDNESDAY AND INTO THE CENTRAL PLAINS OF
NEBRASKA ON THURSDAY. THIS IS A COMPROMISE PATH BETWEEN YESTERDAYS
ECMWF AND GFS...BUT IS CONSISTENT WITH THE CANADIAN MODEL AS WELL.
MODELS DIVERGE AFTER THURSDAY WITH GFS PINWHEELING THE LOW TO THE
NORTH INTO THE DAKOTAS WHILE THE OTHER MODELS CONTINUE
NORTHEASTWARD TRACK INTO THE GREAT LAKES. AS PREVIOUSLY STATED
THIS TYPE OF SYSTEM CAN BE A SIGNIFICANT PRECIPITATION PRODUCER
FOR THE AREA IF IT PUSHES THE RIGHT TRACK...BASICALLY FROM SALT
LAKE TO RAPID CITY. HOWEVER THIS SYSTEM IS NOW TRACKING FAR
ENOUGH SOUTH THAT EVEN IF THE GFS SOLUTION VERIFIES THE BULK OF
THE PRECIPITATION WILL BE EAST AND SOUTH OF THE AREA. WILL STILL
BE UNDER THE TROF WITH COLD AIR IN PLACE FOR A SIGNIFICANT PERIOD
SO EXPECT UNSETTLED COLD CONDITIONS NEXT WEEK. SHOULD THE SYSTEM
TRACK FURTHER NORTH AND WEST WILL NEED TO BUMP PRECIPITATION
CHANCES UP. WITH UNCERTAINTY BUILDING IN THE MODELS AFTER THURSDAY
KEPT BELOW NORMAL TEMPERATURES AND CLIMO TYPE PRECIPITATION
CHANCES IN PLACE FOR THE LATER EXTENDED. CHAMBERS
&&
.AVIATION...
SOUTHWEST WINDS WILL REMAIN STRONG TONIGHT AT KLVM WITH SOME
GUSTS TO 50KTS. THE WINDS WILL DECREASE SUNDAY MORNING. BY THE
EARLY MORNING HOURS...A PACIFIC STORM SYSTEM WILL BRING INCREASING
SNOW SHOWERS TO THE AREA WITH CEILINGS LOWERING TO NEAR MVFR
LEVELS. MOUNTAIN OBSCURATIONS WILL DEVELOP AFTER MIDNIGHT AND
CONTINUE THROUGH THE DAY SUNDAY. SOME MVFR CONDITIONS WILL BE
POSSIBLE WITH SCATTERED SNOW SHOWERS AND LOWERING CEILINGS BY
SUNDAY MORNING...MAINLY FROM LOCATIONS ALONG AND SOUTH OF A KBIL
TO KLVM LINE. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
SUN MON TUE WED THU FRI SAT
-----------------------------------------------------------
BIL 034/043 021/032 014/030 015/026 013/027 016/033 020/034
16/J 43/J 01/B 23/S 32/S 21/B 11/B
LVM 033/039 018/034 014/032 016/028 013/029 016/034 016/034
66/J 42/J 02/J 34/S 32/S 22/S 22/J
HDN 028/041 020/030 009/029 014/028 010/027 010/032 015/033
06/J 53/J 01/B 13/S 42/S 21/B 11/B
MLS 032/043 019/026 007/027 011/025 010/025 011/026 014/029
06/J 64/J 00/B 12/S 32/S 22/S 11/B
4BQ 030/041 020/027 008/027 011/028 011/027 010/027 013/029
05/J 63/J 00/U 14/S 43/S 22/S 11/B
BHK 027/040 017/020 002/020 005/019 006/020 005/022 011/024
04/J 65/J 00/U 02/S 33/S 32/S 21/B
SHR 022/039 017/029 008/030 015/029 009/028 010/032 015/033
05/J 53/J 00/B 14/S 43/S 22/S 12/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 8 AM MST SUNDAY FOR ZONES
65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 PM EST SAT FEB 16 2013
.SYNOPSIS...
LOW PRESSURE INTENSIFYING OFF THE CAROLINA COAST WILL MOVE NORTHEAST
AWAY FROM THE AREA OVERNIGHT. HIGH PRESSURE WILL BUILD IN FROM THE
SOUTHWEST SUNDAY AND SUNDAY NIGHT. THE HIGH WILL MOVE OFF THE
SOUTHEAST COAST ON MONDAY... THEN ANOTHER STORM SYSTEM WILL APPROACH
FROM THE WEST AND BRING RAIN CHANCES FOR TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 PM SATURDAY...
INTERESTING SNOW EVENT HERE FOR CENTRAL NC WITH WIDELY VARYING
TOTALS RANGING FROM ALMOST NOTHING (MELTED AS IT FELL) TO ABOUT TWO
AND A HALF INCHES. RAPID CLASSIC CYCLOGENESIS IS CURRENTLY TAKING
PLACE OFF THE NC COAST... NOTED WELL IN IR AND WATER VAPOR IMAGERY
BY THE DISTINCT BAROCLINIC LEAF STRUCTURE AND WITH A VERY STRONG
(170+ KT) UPPER JET CORE OFF THE COAST... AND BY THE INCREASE IN
LIGHTNING STRIKES EAST OF HATTERAS. WE STILL HAVE FOCUSED AREAS OF
SNOW... ONE OVER NORTHEAST SC ASSOCIATED WITH INTENSE DVPA
(OCCURRING WITH 500 MB VORTICITY MAX PASSAGE) AND UPRIGHT
INSTABILITY... WHILE ANOTHER BAND OF SNOW ROTATES ACROSS THE
NORTHEAST FORECAST AREA ASSOCIATED WITH A MID LEVEL DEFORMATION
BAND. THE FORMER FEATURE AND ITS VIGOROUS LIFT HAS LARGELY HELD
SOUTH OF THE NC/SC BORDER AS WAS SUGGESTED BY RECENT HRRR RUNS...
AND WILL CONTINUE TO MOVE ESE AWAY FROM CENTRAL NC. THE LATTER
FEATURE IS FORECAST TO WEAKEN AND SLIDE EASTWARD OVER THE NEXT FEW
HOURS... ALTHOUGH IT MAY DROP ANOTHER QUICK DUSTING TO ISOLATED HALF
INCH AMOUNTS IN AREAS NORTH AND EAST OF RALEIGH. SURFACE FLOW HAS
BECOME NORTHWESTERLY AND CYCLONIC OVER CENTRAL NC AND DOWNSLOPE
DRYING ALONG WITH INCREASING SUBSIDENCE BEHIND THE DEPARTING 850-700
MB TROUGH IS HELPING TO SCOUR OUT CLOUDS WEST TO EAST. THIS TREND
SHOULD CONTINUE WITH THE REMAINING LIGHT SNOW DIMINISHING THROUGH
08Z... ENDING LAST IN AREAS EAST OF RWI/GSB. THE INFLUX OF VERY DRY
AIR HAS BEEN IMPRESSIVE WITH DEW POINTS ALREADY HAVING DROPPED FROM
THE LOW 30S INTO THE LOW-MID TEENS IN THE TRIAD... AND THIS TREND
TOO SHOULD PERSIST INTO THE OVERNIGHT HOURS... AS THE DRY AIR
SPREADS EASTWARD WHILE TEMPERATURES DROP INTO THE 20S. WHILE 4 INCH
SOIL TEMPS ARE STILL SITTING IN THE LOW-MID 40S... ROAD SURFACES ARE
MARKEDLY COOLER... ESPECIALLY BRIDGES AND OVERPASSES WHICH ARE
LIKELY TO SEE SOME REFREEZING OF THE RESIDUAL WATER ON ROADS
OVERNIGHT. AS SUCH... THE EARLIER WINTER WEATHER ADVISORY FOR SNOW
HAS BEEN CANCELED EARLY... AND ANOTHER ADVISORY FOR BLACK ICE WILL
BE ISSUED FROM MIDNIGHT UNTIL 11 AM SUNDAY MORNING... WHEN TEMPS ARE
EXPECTED TO SURPASS THE FREEZING MARK OVER MUCH OF THE AREA. LOWS
TONIGHT 23-28. -GIH
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 240 PM SATURDAY...
THE SHORT TERM PERIOD WILL START WITH A COLD UPPER TROUGH OVER THE
EASTERN US...WHILE AT THE SURFACE...HIGH PRESSURE WILL GRADUALLY
BUILD IN BEHIND THE DEPARTING LOW THAT WILL BE TRACKING UP THE EAST
COAST. HIGHS ON SUNDAY WILL BE RATHER CHILLY...WITH TEMPS ONLY
RISING INTO THE MID/UPPER 30S TO LOWER 40S. IN ADDITION...WINDS WILL
BE QUITE BREEZY AS THE PRESSURE GRADIENT REMAINS TIGHT OVER THE AREA
BETWEEN THE DEPARTING AND DEEPENING LOW AND THE HIGH BUILDING IN.
THE PRESSURE GRADIENT WILL RELAX SUNDAY NIGHT AS THE HIGH BUILDS
NEARLY OVERHEAD AND GOOD RADIATIONAL COOLING CONDITIONS WILL SET
UP...ALLOWING OVERNIGHT LOWS TO FALL INTO THE LOW TO MID 20S. TEMPS
WILL BEGIN TO MODERATE ON MONDAY AS SHORTWAVE RIDGING BUILDS EAST
AND THE HIGH SLIPS OFFSHORE RESULTING IN A RETURN TO SOUTHERLY FLOW.
HIGHS IN THE UPPER 40S TO LOW/MID 50S ARE EXPECTED ON MONDAY...WITH
OVERNIGHT LOWS GENERALLY IN THE LOW/MID 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 240 PM SATURDAY...
SOUTHERLY FLOW WILL INCREASE AHEAD OF AN APPROACHING FRONT ON
TUESDAY AND THIS WILL ALLOW TEMPS TO WARM EVEN MORE...WITH HIGHS
POSSIBLY APPROACHING 60 DEGREES ACROSS THE SOUTHEAST. HOWEVER...
FURTHER TO THE NORTH AND WEST...INCREASING CLOUDS/PRECIP CHANCES
EARLIER IN THE DAY SHOULD HOLD TEMPS IN THE LOW/MID 50S (MAYBE EVEN
SOME UPPER 40S). THE FRONT IS EXPECTED TO CROSS THE REGION THROUGH
TUESDAY EVENING AND BRING WITH IT A GOOD CHANCE OF SHOWERS. BEHIND
THE FRONT...THERE SHOULD BE ENOUGH CLEARING TUESDAY NIGHT WHERE
TEMPS WOULD DROP INTO THE LOW/MID 30S.
SURFACE HIGH PRESSURE AND SHORTWAVE RIDGING WILL THEN DOMINATE THE
WEATHER ACROSS CENTRAL NC THROUGH THURSDAY. THIS WILL RESULT IN FAIR
WEATHER CONDITIONS AND NEAR NORMAL TEMPS. THE NEXT SYSTEM LOOKS TO
APPROACH THE AREA LATE THURSDAY NIGHT INTO FRIDAY. ALSO...THERE
CONTINUES TO BE INDICATIONS OF A CAD EVENT SETTING UP ACROSS THE
REGION AND THIS WILL HAVE TO BE MONITORED FOR POTENTIAL P-TYPE
ISSUES (ESPECIALLY AT THE ONSET OF ANY PRECIP) AND COOLER THAN
EXPECTED TEMPS...ESPECIALLY ACROSS THE NORTHWEST. FOR NOW...WILL
SHOW RAIN CHANCES INCREASING FROM WEST TO EAST DURING THE DAY ON
FRIDAY...WITH HIGHS RANGING FROM THE 40S ACROSS THE NORTHWEST TO
UPPER 50S (MAYBE NEAR 60 DEGREES) ACROSS THE EXTREME SOUTHEAST.
THERE IS UNCERTAINTY WITH RESPECT TO HOW QUICKLY THIS SYSTEM WILL
PROGRESS ACROSS THE REGION...WITH THE ECMWF MAINTAINING PRECIP
CHANCES THROUGH SATURDAY AS THE FRONT STALLS NEAR THE REGION. FOR
NOW WILL SHOW PRECIP ENDING ON SATURDAY...BUT CLOUDY CONDITIONS
PERSISTING.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 645 PM SATURDAY...
A STRONG LOW PRESSURE CURRENTLY CROSSING THE REGION CONTINUES TO
PRODUCE BANDS OF LIGHT TO MODERATE SNOW OVER CENTRAL NC...WITH THE
HEAVIEST AREA OF SNOW FOCUSED JUST SOUTH OF KCLT INTO SC. THE MAIN
BROKEN BAND OF SNOW CURRENTLY STRETCHES FROM KAFP TO KRDU TO
KHNZ...WITH VSBYS PREDOMINATELY IN THE 3-6SM RANGE AND POCKETS OF
LOCALLY HEAVIER SNOW AND LOWER VSBYS. NEAR TERM MODELS SUGGEST
THERE MAY BE SOME ADDITIONAL STRENGTHENING AND FILLING IN OF THE
BAND AS IT MOVES EAST OF KRDU TOWARD KFAY AND KRWI THROUGH 06Z.
HOWEVER... IT APPEARS SNOW WILL NOT BE HEAVY ENOUGH TO DROP VSBYS
BELOW 1-2SM.
AS THE LOW STRENGTHENS OFF THE NC COAST AND BEGINS TO MOVE NORTHEAST
AWAY FROM THE AREA TONIGHT...DRIER AIR WILL SPREAD ACROSS
NC...SCOURING OUT THE LOW CLOUDS AND EVENTUALLY BRINGING ALL SITES
BACK TO VFR. NORTHWESTERLY WINDS MAY GUST TO NEAR 20KT AT TIMES
OVERNIGHT...INCREASING TO AROUND 12KT WITH GUSTS TO 25-30KT DURING
THE DAY ON SUNDAY.
OUTLOOK...
THE NEXT CHANCE FOR ADVERSE AVIATION CONDITIONS WILL OCCUR
ON TUESDAY AS ANOTHER SYSTEM APPROACHES THE AREA. VFR CONDITIONS ARE
THEN EXPECTED AGAIN PM WEDNESDAY AND THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...SMITH
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
824 PM CST SAT FEB 16 2013
.UPDATE...
CLOUDS AND TEMPERATURES THE MAIN CHALLENGE. THE WESTERN EDGE OF
THE LOW CLOUD DECK WILL LIKELY REMAIN IN PLACE UNTIL LOW-LEVEL
FLOW BECOMES WESTERLY (ON SUNDAY). THE EASTERN EDGE SHOULD
CONTINUE TO ADVECT TO THE EAST AND OVERTAKE THE ENTIRE FA SOMETIME
TONIGHT. KEPT TEMPS STEADY WHERE CLOUDS ARE CURRENTLY
LOCATED...AND ALLOWED FOR SOME DROP ACROSS THE NORTHEAST FA WHERE
SKIES ARE CURRENTLY CLEAR. THE OTHER CONCERN WILL BE FOG/DRIZZLE
POTENTIAL. EXPECTING BREEZY CONDITIONS OVERNIGHT...AND THIS MIXING
SHOULD PREVENT FOG/DRIZZLE. FORECAST IS IN GOOD SHAPE AND ONLY
MINOR CHANGES NEEDED.
&&
.SHORT TERM...
TEMPS TONIGHT A CHALLENGE ONCE AGAIN. LOW CLOUDS/FOG FROM THIS
MORNING CLEARED OFF AND A SOUTH-SOUTHEAST WIND HELPING TO WARM
THINGS UP A BIT...BUT TEMPS QUITE VARIABLE WITH TEMPS STRUGGLING
INTO THE MID TEENS IN MOST OF THE FCST AREA WHILE A FEW SPOTS IN
THE MN TREES SEEING MID 20S. AREA OF CLOUD COVER DVL-JMS REGION
REALLY BREAKING UP SOME THIS AFTN BUT IDEA IS THESE CLOUDS ASSOC
WITH 850MB WARM ADV WILL SPREAD EAST TONIGHT. UPSTREAM CANADIAN
RADAR AND OBS SHOWS SOME LIGHT SNOW BRANDON-DAUPHIN-PORTAGE MB
REGION AND DID COORD WITH WFO BIS AND SPREAD SOME FLURRIES
SOUTHEAST THIS EVENING INTO NE ND. FOR LATER TONIGHT...CLOUD BAND
MOVES MORE INTO MN FCST AREA AND RAP ISENTROPIC FCSTS INDICATE
SOME LIFT 750-850 MB REGION DEVELOPING IN BDE-BJI AREA BY 12Z SUN.
THUS KEPT LOW POP FOR -SN IN LAKE OF THE WOODS REGION AND SPREAD
MENTION OF FLURRIES A BIT MORE BACK INTO NRN VALLEY AND REST OF NW
MN. BUFKIT SOUNDINGS SHOW PTYPE ALL -SN THRU 12Z.
AS FOR TEMPS...QUITE CHALLENGING AS SHOULD SEE SOME DROP AGAIN IN
THE EAST BUT OTHERWISE FAIRLY STEADY IF NOT RISE A BIT OVERNIGHT
IN ERN ND. USED A BLEND OF MODEL GUIDANCE FOR HOURLY TEMPS.
FOR SUNDAY...MAIN ISENTROPIC LIFT HANGS OVER LAKE OF THE WOODS
REGION WITH MAJORITY OF THE FCST IN DRY SLOT AT 850 MB. SOUNDINGS
DO SHOW SOME 925 MB MOISTURE BUT LIFT IN THAT LAYER APPEARS
INSUFFICIENT TO PRODUCE ANY FZDZ WE HAD IN THE PREV FCST. THROUGH
COORD WITH ABR/MPX/BIS REMOVED FZDZ MENTION SUNDAY. PTYPES IN FAR
NW MN WHERE POPS ARE WOULD BE -SN. TEMPS SHOULD WARM ESP LATER ON
IN THE DAY AS WINDS TURN A MORE WEST AND ALLOW TEMPS TO WARM INTO
THE LOWER 30S. OTHERWISE EXPECT A STIFF SOUTH-SOUTHEAST WINDS LATE
TONIGHT THRU SUNDAY MIDDAY.
12Z GFS MODEL A BIT MORE LIKE THE OTHER MODELS NOW IN REGARDS TO
SUN NIGHT-MON SYSTEM. 00Z/06Z SAT RUNS A BIT AGGRESSIVE. SFC LOW
WILL MOVE FROM EC SASK INTO SW MB SUNDAY AFTN THEN TOWARD LAKE OF
THE WOODS REGION 06Z MON. MAIN SNOW WITH THIS LOW AND KEPT IDEA OF
2-4 INCHES IN RRT/BDE AREAS. OTHERWISE MAIN ACTION WILL WAIT WITH
COLD FRONT WHICH WILL DROP DOWN SUN LATE NIGHT INTO MONDAY
MORNING. SHOULD SEE SOME LIGHT SNOW WITH THIS...MORE SNOW
SHOWERY...ALONG WITH A PD OF STRONG WINDS MONDAY. BUFKIT SOUNDINGS
SHOW ADIABATIC TO AROUND 880 MB AT GFK/FAR MONDAY MIDDAY WHERE
WINDS OF 30-35 KTS SHOULD MIX DOWN. STRONG COLD ADV AS WELL AS
HIGH BUILDS IN AND SFC LOW STRENGTHENS TO OUR EAST. ISSUED A
SPECIAL WX STATEMENT FOR MONDAY AS WIND AND LIGHT SNOW WILL CAUSE
BLOWING SNOW AND LIKELY NASTY TRAVEL CONDITIONS.
TEMPS TO DROP WELL BLOW ZERO MONDAY NIGHT AND RECOVER ONLY
SLIGHTLY TO THE SINGLE DIGITS ABOVE AND BLO ZERO TUESDAY WITH
DIMINISHING WINDS. WIND CHILLS THOUGH EARLY TUESDAY MAY DROP TO
-30 TO -35F IN NE ND.
.LONG TERM (TUE NIGHT-SAT)...
MID LEVEL RIDGING AND SFC HIGH PRESSURE SHOULD BE OVER THE FA TO
START THE LONG TERM PERIOD. WITH THE SFC HIGH AND A COLD AIRMASS IN
PLACE TEMPS WILL STILL BE CHILLY TUE NIGHT INTO WED. FLOW WILL
TRANSITION BACK TO THE SOUTHWEST WITH ANOTHER COLORADO LOW SYSTEM
EJECTING OUT ON THU. HPC MEAN TAKES THIS LOW FROM SE COLORADO AT 12Z
THU TO NEAR CHICAGO BY 12Z FRI WHICH USES A GLOBAL MEAN. LATEST RAW
12Z MODEL GUIDANCE FROM BOTH THE ECMWF AND GFS IS FURTHER WEST WITH
THE SFC LOW. THEREFORE THERE IS STILL UNCERTAINTY WITH THE TRACK OF
THIS NEXT SYSTEM YET. AS FOR NOW WILL LEAVE HIGHER THAN GUIDANCE
PCPN CHANCES ACROSS THE SOUTHEAST FA FOR THU INTO THU NIGHT AND SEE
WHAT LATER RUNS HAVE IN STORE. MAY BE LINGERING LIGHT SNOW FROM THIS
SYSTEM ALL THE WAY INTO SAT.
&&
.AVIATION...GAINING MORE CONFIDENCE THAT LOW CLOUDS (MVFR/IFR)
WILL HANG AROUND TONIGHT INTO MUCH OF SUNDAY. LOW LEVEL FLOW WILL
REMAIN SOUTH/SOUTHWEST INTO SUNDAY AFTERNOON. LOW LEVEL WESTERLY
FLOW WILL LIKELY BE NEEDED TO ADVECT THESE CLOUDS TO THE
EAST...WHICH DOES NOT OCCUR UNTIL LATE SUNDAY AFTERNOON (EXCEPT
FOR KDVL WHICH MAY HAVE LOW LEVEL WESTERLY FLOW BY LATE TONIGHT).
21Z RAP GUIDANCE SUGGESTS THAT LOW CLOUDS WILL REMAIN AND SPREAD
EASTWARD THROUGH THE NIGHT...WITH SOME FOG POSSIBLE. STUCK CLOSE
TO THE 21Z RAP GUIDANCE FOR THIS SET OF TAF FORECASTS CONSIDERING
THE ABOVE THINKING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
AVIATION...TG
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
526 PM CST SAT FEB 16 2013
UPDATED AVIATION SECTION
.SHORT TERM...
TEMPS TONIGHT A CHALLENGE ONCE AGAIN. LOW CLOUDS/FOG FROM THIS
MORNING CLEARED OFF AND A SOUTH-SOUTHEAST WIND HELPING TO WARM
THINGS UP A BIT...BUT TEMPS QUITE VARIABLE WITH TEMPS STRUGGLING
INTO THE MID TEENS IN MOST OF THE FCST AREA WHILE A FEW SPOTS IN
THE MN TREES SEEING MID 20S. AREA OF CLOUD COVER DVL-JMS REGION
REALLY BREAKING UP SOME THIS AFTN BUT IDEA IS THESE CLOUDS ASSOC
WITH 850MB WARM ADV WILL SPREAD EAST TONIGHT. UPSTREAM CANADIAN
RADAR AND OBS SHOWS SOME LIGHT SNOW BRANDON-DAUPHIN-PORTAGE MB
REGION AND DID COORD WITH WFO BIS AND SPREAD SOME FLURRIES
SOUTHEAST THIS EVENING INTO NE ND. FOR LATER TONIGHT...CLOUD BAND
MOVES MORE INTO MN FCST AREA AND RAP ISENTROPIC FCSTS INDICATE
SOME LIFT 750-850 MB REGION DEVELOPING IN BDE-BJI AREA BY 12Z SUN.
THUS KEPT LOW POP FOR -SN IN LAKE OF THE WOODS REGION AND SPREAD
MENTION OF FLURRIES A BIT MORE BACK INTO NRN VALLEY AND REST OF NW
MN. BUFKIT SOUNDINGS SHOW PTYPE ALL -SN THRU 12Z.
AS FOR TEMPS...QUITE CHALLENGING AS SHOULD SEE SOME DROP AGAIN IN
THE EAST BUT OTHERWISE FAIRLY STEADY IF NOT RISE A BIT OVERNIGHT
IN ERN ND. USED A BLEND OF MODEL GUIDANCE FOR HOURLY TEMPS.
FOR SUNDAY...MAIN ISENTROPIC LIFT HANGS OVER LAKE OF THE WOODS
REGION WITH MAJORITY OF THE FCST IN DRY SLOT AT 850 MB. SOUNDINGS
DO SHOW SOME 925 MB MOISTURE BUT LIFT IN THAT LAYER APPEARS
INSUFFICIENT TO PRODUCE ANY FZDZ WE HAD IN THE PREV FCST. THROUGH
COORD WITH ABR/MPX/BIS REMOVED FZDZ MENTION SUNDAY. PTYPES IN FAR
NW MN WHERE POPS ARE WOULD BE -SN. TEMPS SHOULD WARM ESP LATER ON
IN THE DAY AS WINDS TURN A MORE WEST AND ALLOW TEMPS TO WARM INTO
THE LOWER 30S. OTHERWISE EXPECT A STIFF SOUTH-SOUTHEAST WINDS LATE
TONIGHT THRU SUNDAY MIDDAY.
12Z GFS MODEL A BIT MORE LIKE THE OTHER MODELS NOW IN REGARDS TO
SUN NIGHT-MON SYSTEM. 00Z/06Z SAT RUNS A BIT AGGRESSIVE. SFC LOW
WILL MOVE FROM EC SASK INTO SW MB SUNDAY AFTN THEN TOWARD LAKE OF
THE WOODS REGION 06Z MON. MAIN SNOW WITH THIS LOW AND KEPT IDEA OF
2-4 INCHES IN RRT/BDE AREAS. OTHERWISE MAIN ACTION WILL WAIT WITH
COLD FRONT WHICH WILL DROP DOWN SUN LATE NIGHT INTO MONDAY
MORNING. SHOULD SEE SOME LIGHT SNOW WITH THIS...MORE SNOW
SHOWERY...ALONG WITH A PD OF STRONG WINDS MONDAY. BUFKIT SOUNDINGS
SHOW ADIABATIC TO AROUND 880 MB AT GFK/FAR MONDAY MIDDAY WHERE
WINDS OF 30-35 KTS SHOULD MIX DOWN. STRONG COLD ADV AS WELL AS
HIGH BUILDS IN AND SFC LOW STRENGTHENS TO OUR EAST. ISSUED A
SPECIAL WX STATEMENT FOR MONDAY AS WIND AND LIGHT SNOW WILL CAUSE
BLOWING SNOW AND LIKELY NASTY TRAVEL CONDITIONS.
TEMPS TO DROP WELL BLOW ZERO MONDAY NIGHT AND RECOVER ONLY
SLIGHTLY TO THE SINGLE DIGITS ABOVE AND BLO ZERO TUESDAY WITH
DIMINISHING WINDS. WIND CHILLS THOUGH EARLY TUESDAY MAY DROP TO
-30 TO -35F IN NE ND.
.LONG TERM (TUE NIGHT-SAT)...
MID LEVEL RIDGING AND SFC HIGH PRESSURE SHOULD BE OVER THE FA TO
START THE LONG TERM PERIOD. WITH THE SFC HIGH AND A COLD AIRMASS IN
PLACE TEMPS WILL STILL BE CHILLY TUE NIGHT INTO WED. FLOW WILL
TRANSITION BACK TO THE SOUTHWEST WITH ANOTHER COLORADO LOW SYSTEM
EJECTING OUT ON THU. HPC MEAN TAKES THIS LOW FROM SE COLORADO AT 12Z
THU TO NEAR CHICAGO BY 12Z FRI WHICH USES A GLOBAL MEAN. LATEST RAW
12Z MODEL GUIDANCE FROM BOTH THE ECMWF AND GFS IS FURTHER WEST WITH
THE SFC LOW. THEREFORE THERE IS STILL UNCERTAINTY WITH THE TRACK OF
THIS NEXT SYSTEM YET. AS FOR NOW WILL LEAVE HIGHER THAN GUIDANCE
PCPN CHANCES ACROSS THE SOUTHEAST FA FOR THU INTO THU NIGHT AND SEE
WHAT LATER RUNS HAVE IN STORE. MAY BE LINGERING LIGHT SNOW FROM THIS
SYSTEM ALL THE WAY INTO SAT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
GAINING MORE CONFIDENCE THAT LOW CLOUDS (MVFR/IFR) WILL HANG
AROUND TONIGHT INTO MUCH OF SUNDAY. LOW LEVEL FLOW WILL REMAIN
SOUTH/SOUTHWEST INTO SUNDAY AFTERNOON. LOW LEVEL WESTERLY FLOW
WILL LIKELY BE NEEDED TO ADVECT THESE CLOUDS TO THE EAST...WHICH
DOES NOT OCCUR UNTIL LATE SUNDAY AFTERNOON (EXCEPT FOR KDVL WHICH
MAY HAVE LOW LEVEL WESTERLY FLOW BY LATE TONIGHT). 21Z RAP
GUIDANCE SUGGESTS THAT LOW CLOUDS WILL REMAIN AND SPREAD EASTWARD
THROUGH THE NIGHT...WITH SOME FOG POSSIBLE. STUCK CLOSE TO THE 21Z
RAP GUIDANCE FOR THIS SET OF TAF FORECASTS CONSIDERING THE ABOVE
THINKING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
641 PM EST SAT FEB 16 2013
.SYNOPSIS...
IN THE WAKE OF A DEPARTING UPPER LEVEL TROUGH...HIGH PRESSURE
WILL BUILD OVER THE AREA ON SUNDAY. RETURN FLOW AND SOUTHERLY
WINDS WILL BRING WARMER AIR TO THE REGION MONDAY AND OVERNIGHT
AHEAD OF THE NEXT COLD FRONT THAT WILL CROSS LATE MONDAY NIGHT.
RAIN WILL OVERSPREAD THE REGION AHEAD OF THIS NEXT FRONTAL
PASSAGE.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPPER LEVEL TROUGH IS MOVING EAST THROUGH THE NORTHERN OHIO
VALLEY/GREAT LAKES REGION TONIGHT. THE BEST COLD PUSH IS ONGOING
RIGHT NOW AND HELPING TO CONTINUE THE CONVECTION GOING ON THIS
AFTERNOON. WITH THE LOSS OF DAYTIME INSOLATION THE SURFACE WILL
COOL OFF TONIGHT AND THERMAL DIFFERENTIAL CAUSING THE SNOW
SHOWERS WILL QUICKLY DISSIPATE THIS EARLY EVENING...EVEN AS THE
COLDEST AIR CONTINUES TO SETTLE OVER THE REGION LATE TONIGHT.
NAM AND HRRR WERE PREVIOUSLY SHOWING A WEAK AREA OF FORCING AND
LIGHT SNOW RUNNING FROM ABOUT INDIANAPOLIS AT 0Z TONIGHT TOWARDS
CINCINNATI AROUND 6Z AND THEN SOUTH OF A MAYSVILLE/VANCEBURG LINE
BY DAYBREAK. I INCLUDED SOME LIGHT SNOW IN THESE AREAS BUT THE
ACTUAL OCCURRENCE OF THIS EVENT REMAINS TO BE SEEN AND MAY NOT
MATERIALIZE.
SKY COVER IS QUITE CELLULAR LOOKING IN NATURE AND SHOULD DISSIPATE
RELATIVELY QUICKLY OUTSIDE OF CENTRAL OHIO TONIGHT...AND IN THE
INDY-CINCY-NORTHERN KY LINE PREVIOUSLY MENTIONED FOR INCREASED
SNOW POTENTIAL. THIS RELATIVE CLEARING WILL LET TEMPERATURES DROP
INTO THE TEENS WITH SOME SINGLE DIGITS POSSIBLY IN COLDER LOW-
LYING AREAS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
A BRIEF RESPITE BETWEEN SYSTEMS WILL BE FOUND SUNDAY AND WARMER
AIR WILL REALLY BEGIN TO BE USHERED IN MONDAY AFTER A MINOR DROP
OR RELATIVELY STEADY TEMPERATURES IN THE LOWER 20S SUNDAY NIGHT.
MILD AIR ON MONDAY AND OVERNIGHT WILL BE SHORT LIVED. RAIN WILL
SPREAD EAST IN THE EVENING AS THE DAYTIME SHOULD JUST SEE
INCREASING CLOUD COVER FROM WEST TO EAST. THE RAIN WILL BE
EVERYWHERE BY MIDNIGHT AND IS EXPECTED TO TAIL OFF QUICKLY WITH
THE PASSAGE OF THE FRONT...BEFORE DAYBREAK IN INDIANA. WINDS WILL
SHIFT WEST BEHIND THE FRONT AND DRIER AIR BEING USHERED IN WILL
MARK THE END OF THE RAIN. TEMPERATURES IN THE WARM SECTOR MONDAY
SHOULD RISE INTO THE UPPER 40S AND LOW 50S...WITH SOME MID 50S
POSSIBLE IN KENTUCKY.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
PERIOD BEGINS WITH A CDFNT FORECASTED TO BE PUSHING ACROSS THE
FA. EXACT PLACEMENT OF THE FRONT AT 12Z TUESDAY WILL AFFECT THE
PCPN TYPE AND POPS FOR THE FIRST FEW HOURS OF THE DAY. THE 12Z NAM
APPEARS TO BE THE QUICKEST WITH THE FRONT...PUSHING IT INTO THE
APPALACHIANS ALREADY. THE MORE GLOBAL MODELS HAVE THE FRONT
SLOWER...MAYBE AROUND I-75. TRENDED TOWARDS THE CONSENSUS...THUS
KEPT LIKELY POPS IN THE E AHEAD OF THE FNT...BUT DRIED OUT THE
POPS POST FRONTAL. WITH FROPA SO EARLY...WILL PROBABLY SEE FALLING
OR STEADY TEMPERATURES FOR TUESDAY. ALSO THREW IN A MENTION OF A
CHC OF SNOW SHOWERS FOR LATE TUE MORNING INTO TUE AFTN AS THE
MODELS ARE SHOWING CYCLONIC SFC FLOW COMBINING WITH WLY CAA AT H8.
HIGH PRESSURE BUILDS DOWN INTO THE LOWER OHIO VALLEY TUE NIGHT
INTO WED BEFORE LIFTING NE ACROSS THE FA WED NGT. THIS SHOULD
PROVIDE DRY CONDITIONS FOR THE PERIOD...WITH NRN SECTIONS SEEING
MORE CLOUDS THAN THE S TUE NGT AND WED...BEFORE MOSTLY CLEAR SKIES
PREVAIL WED NGT.
SYSTEM DIGS INTO THE SRN ROCKIES WED NGT...THEN EJECTS OUT THU
INTO THU NGT. MODELS ARE SHOWING THEIR TYPICAL SPREAD. THE CMC IS
THE QUICKEST THIS RUN IN BRINGING RETURN PCPN TO THE FA THU AFTN.
THE 12Z RUNS OF THE GFS AND ECMWF ARE SLOWER...LIMITING POPS TO
THE SW. THICKNESSES WILL BE COLD ENUF FOR SOME RAIN/SNOW AT THE
ONSET. AS THE CENTER OF THE SYSTEM LIFTS OUT THRU THE PLAINS...AN
AREA OF PCPN WILL BE PUSHED ACROSS THE FA THU NGT INTO FRI. PCPN
WILL EITHER BE SN OR RA/SN MIX UNTIL A WRMFNT GRADUALLY BRINGS IN
WARMER AIR CHANGING THE PCPN TO RA BEFORE IT ENDS ON FRIDAY. HIGH
PRESSURE THEN BUILDS IN FOR FRIDAY.
COLD AIR WILL WORK IN TUESDAY NIGHT DROPPING TEMPERATURES IN THE
TEENS AND LOWER 20S. THE COOL NLY FLOW ON WED WILL KEEP TEMPS DOWN
IN THE UPPER 20S N TO THE MID 30S NRN KY. THE CLEAR SKIES WILL
ALLOW TEMPERATURES TO DROP BACK INTO THE TEENS AND LOWER 20S
AGAIN. ONLY EXPECT HIGHS ON THU TO MAKE THE 30S AHEAD OF THE STORM
SYSTEM...BUT WITH RISING TEMPS THU NGT. HIGHS FRIDAY SHOULD MAKE
THE 40S AS THE REGION GETS WARM SECTORED.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
MOSTLY VFR DECK WILL REMAIN ACROSS THE REGION THROUGH THE FIRST
PART OF THE TAF PERIOD. APPEARS THAT ANOTHER BURST OF SNOW SHOWERS
WILL PUSH THROUGH THE COLUMBUS AREA BY 02Z WHICH WILL TEMPORARILY
LOWER CONDITIONS THERE. NEBULOUS SIGNALS WHETHER ANY OTHER SNOW
SHOWERS COULD AFFECT THE TERMINALS THROUGH THE NIGHT. SO HAVE KEPT
VFR CONDITIONS OTHERWISE. CLOUDS WILL SCATTER DURING THE DAY
EXCEPT PERHAPS IN CENTRAL OHIO WITH WINDS EVENTUALLY BACKING TO
SOUTHWEST.
OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE MONDAY NIGHT AND EARLY
TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...FRANKS
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1145 AM EST FRI FEB 15 2013
.SYNOPSIS...
A WEAK WAVE PASSING TO OUR SOUTH WILL SPREAD SOME LIGHT RAIN AND
SNOW OVER THE SOUTHERN PARTS OF THE REGION LATE TODAY AND
TONIGHT. A COLD NORTHWEST FLOW WILL PREVAIL FOR THE REMAINDER OF
THE WEEKEND WITH SCATTERED LAKE EFFECT SNOW SHOWERS AND FLURRIES.
SOME MODERATION IN TEMPERATURES IS EXPECTED EARLY NEXT WEEK WITH
ANOTHER FRONTAL SYSTEM EXPECTED TO APPROACH BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATYEST NAM AND SREF 09Z RUNS HAVE NUDGED PRECIP ACCUMS HIGHER
THAN PREV SOLNS. HRRR AND NEWEST RUC SUPPORT THE EVOLUTION IN NAM
STYLE ALSO. WILL NUDGE SNOW ACCUMS UP JUST ABOUT 50PCT FOR THE
EVENING...BUT HOLD OFF ON ENOUGH OF A BUMP TO PASS THOUGH THE ADVY
THRESHOLD. KEEPING FCST DOWN AT 1-3 INCHES FOR YORK AND LANCASTER
COS. OTHERWISE NO CHANGES.
THE BIGGEST SHORT TERM FORECAST PROBLEM WILL CENTER ON A WAVE OF
LOW PRESSURE THAT THE MODELS WANT TO SEE DEVELOP ALONG THE WEAK
FRONT THAT WILL BE MOVING THROUGH VIRGINIA. THE GFS IS THE MOST
AGGRESSIVE SNOW MAKER WITH THIS SYSTEM...IMPLYING THAT ADVISORY
SNOWS ARE POSSIBLE OVER THE LOWER SUSQ VALLEY FROM ABOUT ADAMS
COUNTY EASTWARD. THE GEFS IS TAMER...WITH AN INCH OR TWO INDICATED
IN THE THREATS OUTPUT. THE SREF SIMILARLY DOWNPLAYS THE SNOW
POTENTIAL...WHICH ALSO MATCHES THE OPERATIONAL ECMWF. ALL OF WHICH
SHOW THAT DESPITE IT BEING COLD ENOUGH ALOFT...SKIN TEMPS OVER THE
SE WILL BE INITIALLY PRETTY WARM IMPLYING THAT EVEN IF SNOW IS THE
PREDOM PRECIP TYPE...MELTING WILL KEEP NUMBERS DOWN.
HIGHS NEAR FREEZING OVER THE NW TODAY WILL ACTUALLY BE VERY CLOSE
TO MID FEB NORMALS...WHILE TEMPS APPROACHING 50 OVER THE SE WILL
BE MORE LIKE 5 TO 10 DEG ABOVE NORMAL.
TIMING OF THE PRECIP LOOKS LIKE THINGS WILL WIND DOWN DURING THE
EVENING WITH LITTLE MORE BUT SOME LINGERING LIGHT SNOW OR FLURRIES
LEFTOVER AFTER MIDNIGHT. LOWS WILL DROP BACK INTO THE TEENS OVER
THE NW...TO NEAR FREEZING OVER THE SE.
&&
.SHORT TERM /SATURDAY/...
AN UPPER TROUGH/LOW WILL CONTINUE THE PROGRESS OF DEEPENING DOWN
INTO THE EASTERN GR LAKES...HELPING DELIVER A LATE WINTER SHOT OF
ARCTIC AIR. IT DOESN`T LOOK LIKE THE COLDEST AIR WE HAVE
EXPERIENCED THIS WINTER...BUT IT WILL CHILL US DOWN BACK BELOW
NORMAL NONE THE LESS.
PRECIP WILL BE ON THE LIGHT SIDE AND MAINLY CONFINED TO THE USUAL
PARTS OF THE STATE FAVORED BY POST FRONTAL LOW LEVEL COLD
ADVECTION SNOW SHOWERS. EXPECT ACCUMULATIONS TO BE LIGHT OVER THE
NW AS LOW LEVEL WINDS WILL INITIALLY NOT ATTAIN A FAVORABLE OVER-
LAKE TRAJECTORY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE UPPER TROUGH IS FCST TO DEEPEN AND CLOSE OFF TO A TIDY UPPER
LOW OVER OR JUST NORTH OF PA DURING THE DAY SUNDAY. THE VARIOUS
OPERATIONAL MODELS USE THIS DEEPENING SYSTEM ALOFT TO DEVELOP
ANOTHER LOW ALONG THE FRONT ALONG OR JUST OFF THE EAST COAST. THE
GFS/ECMWF ACTUALLY SHOW THE PRECIP BRUSHING THE EAST
COAST...POSSIBLY JUST NUDGING INTO MY SERN ZONES A BIT WITH LIGHT
AMOUNTS SUNDAY. THE GEFS LOOKS MORE REASONABLE HOWEVER KEEPING
PRECIP OUT OF MY FCST AREA AND MAINLY OFFSHORE. SO SUNDAY I KEPT
THE FCST DRY EXCEPT FOR THE USUAL WESTERN SNOW SHOWERS.
THE NEXT SYSTEM OF NOTE LOOKS TO ARRIVE ON TUESDAY. AS THE HIGH
SLIDES OFF TO OUR EAST...WE SHOULD SEE WARM AIR FLOOD BACK INTO
THE REGION MAKING FOR MAINLY A RAIN EVENT WITH THE APPROACHING
FRONT. HOWEVER WE WILL HAVE TO WATCH FOR THE POTENTIAL OF A WINTRY
MIX AT THE ONSET IF THE PRECIP ARRIVES EARLY ENOUGH TUESDAY.
IT WILL COOL DOWN ONCE AGAIN BEHIND THE FRONT FOR MID
WEEK...BEFORE MILDER AIR STARTS TO MOVE BACK TOWARD THE REGION
LATE IN THE WEEK. THE PATTERN IS COMPLICATED HOWEVER WITH MODELS
HINTING AT AN UPPER BLOCK DEVELOPING OVER SOUTHERN CANADA. THIS
COULD SUPPRESS THE WARM AIR AND KEEP US JUST COLD ENOUGH THAT ANY
MOISTURE THAT HEADS OUR WAY COULD CREATE THE POTENTIAL FOR SNOW OR
A WINTRY MIX BY WEEK`S END.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
WAVE SLIDING EAST THROUGH VA THIS EVENING IS ALREADY SPREDING
LIGHT PRECIP THROUGH THE UPPER OH VALLEY. THIS PRECIP SHOULD
CREATE LIMITED VISBYS AT JST-AOO-MDT-LNS LATE THIS AFTN AND ALL
EVENING. THE PRECIP AND LOW CLOUDS WILL LIKELY GET CLOSE TO OR
JUST TO THE NORTH OF UNV...BUT NOT UP TO BFD. HOWEVER...WRLY FLOW
AND THE UPPER LEVEL WAVE TO THE NORTH IS CREATING -SHSN OVER NERN
OH AND THESE COULD IMPACT BFD THROUGH THE EVENING AS WELL. WILL
KEEP MENTIONS OF IFR TO THE SRN TIER TERMINALS...AND ONLY FOR
3-6HRS THIS EVENING - BASICALLY WITHIN A FEW HOURS OF 00Z-03Z.
NW FLOW KICKS IN FOR SAT...WITH TYPICAL N/W TERMINALS IN AND OUT
OF MVFR-IFR CONDS THROUGH SUNDAY. IMPROVING CONDITIONS FOR
MONDAY...AS HIGH PRESSURE BUILDS NORTHWARD.
SOME SHOWERS ON TUE...AS NEXT COLD FRONT MOVES TOWARD THE
AREA.
OUTLOOK...
SAT...SHSN/REDUCED VSBYS POSSIBLE W MTNS...ESP LATE.
SUN...BREEZY WITH SHSN POSSIBLE...MAINLY W MTNS.
MON...NO SIG WX EXPECTED.
TUE...SHRASN/REDUCED CIGS POSSIBLE...MAINLY W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...DANGELO/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1058 AM EST FRI FEB 15 2013
.SYNOPSIS...
A WEAK CLIPPER WILL PASS TO THE NORTH OF THE STATE TODAY. THE
TRAILING FRONT OVER THE VIRGINIAS WILL SPAWN A WEAK WAVE THAT
COULD SPREAD SOME RAIN AND SNOW OVER THE SOUTHEASTERN PARTS OF THE
REGION LATER TODAY AND TONIGHT.
A COLD NORTHWEST FLOW WILL PREVAIL FOR THE REMAINDER OF THE
WEEKEND WITH SCATTERED LAKE EFFECT SNOW SHOWERS AND FLURRIES. SOME
MODERATION IN TEMPERATURES IS EXPECTED EARLY NEXT WEEK WITH ANOTHER
FRONTAL SYSTEM EXPECTED TO APPROACH BY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATYEST NAM AND SREF 09Z RUNS HAVE NUDGED PRECIP ACCUMS HIGHER
THAN PREV SOLNS. HRRR AND NEWEST RUC SUPPORT THE EVOLUTION IN NAM
STYLE ALSO. WILL NUDGE SNOW ACCUMS UP JUST ABOUT 50PCT FOR THE
EVENING...BUT HOLD OFF ON ENOUGH OF A BUMP TO PASS THOUGH THE ADVY
THRESHOLD. KEEPING FCST DOWN AT 1-3 INCHES FOR YORK AND LANCASTER
COS. OTHERWISE NO CHANGES.
THE BIGGEST SHORT TERM FORECAST PROBLEM WILL CENTER ON A WAVE OF
LOW PRESSURE THAT THE MODELS WANT TO SEE DEVELOP ALONG THE WEAK
FRONT THAT WILL BE MOVING THROUGH VIRGINIA. THE GFS IS THE MOST
AGGRESSIVE SNOW MAKER WITH THIS SYSTEM...IMPLYING THAT ADVISORY
SNOWS ARE POSSIBLE OVER THE LOWER SUSQ VALLEY FROM ABOUT ADAMS
COUNTY EASTWARD. THE GEFS IS TAMER...WITH AN INCH OR TWO INDICATED
IN THE THREATS OUTPUT. THE SREF SIMILARLY DOWNPLAYS THE SNOW
POTENTIAL...WHICH ALSO MATCHES THE OPERATIONAL ECMWF. ALL OF WHICH
SHOW THAT DESPITE IT BEING COLD ENOUGH ALOFT...SKIN TEMPS OVER THE
SE WILL BE INITIALLY PRETTY WARM IMPLYING THAT EVEN IF SNOW IS THE
PREDOM PRECIP TYPE...MELTING WILL KEEP NUMBERS DOWN.
HIGHS NEAR FREEZING OVER THE NW TODAY WILL ACTUALLY BE VERY CLOSE
TO MID FEB NORMALS...WHILE TEMPS APPROACHING 50 OVER THE SE WILL
BE MORE LIKE 5 TO 10 DEG ABOVE NORMAL.
TIMING OF THE PRECIP LOOKS LIKE THINGS WILL WIND DOWN DURING THE
EVENING WITH LITTLE MORE BUT SOME LINGERING LIGHT SNOW OR FLURRIES
LEFTOVER AFTER MIDNIGHT. LOWS WILL DROP BACK INTO THE TEENS OVER
THE NW...TO NEAR FREEZING OVER THE SE.
&&
.SHORT TERM /SATURDAY/...
AN UPPER TROUGH/LOW WILL CONTINUE THE PROGRESS OF DEEPENING DOWN
INTO THE EASTERN GR LAKES...HELPING DELIVER A LATE WINTER SHOT OF
ARCTIC AIR. IT DOESN`T LOOK LIKE THE COLDEST AIR WE HAVE
EXPERIENCED THIS WINTER...BUT IT WILL CHILL US DOWN BACK BELOW
NORMAL NONE THE LESS.
PRECIP WILL BE ON THE LIGHT SIDE AND MAINLY CONFINED TO THE USUAL
PARTS OF THE STATE FAVORED BY POST FRONTAL LOW LEVEL COLD
ADVECTION SNOW SHOWERS. EXPECT ACCUMULATIONS TO BE LIGHT OVER THE
NW AS LOW LEVEL WINDS WILL INITIALLY NOT ATTAIN A FAVORABLE OVER-
LAKE TRAJECTORY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE UPPER TROUGH IS FCST TO DEEPEN AND CLOSE OFF TO A TIDY UPPER
LOW OVER OR JUST NORTH OF PA DURING THE DAY SUNDAY. THE VARIOUS
OPERATIONAL MODELS USE THIS DEEPENING SYSTEM ALOFT TO DEVELOP
ANOTHER LOW ALONG THE FRONT ALONG OR JUST OFF THE EAST COAST. THE
GFS/ECMWF ACTUALLY SHOW THE PRECIP BRUSHING THE EAST
COAST...POSSIBLY JUST NUDGING INTO MY SERN ZONES A BIT WITH LIGHT
AMOUNTS SUNDAY. THE GEFS LOOKS MORE REASONABLE HOWEVER KEEPING
PRECIP OUT OF MY FCST AREA AND MAINLY OFFSHORE. SO SUNDAY I KEPT
THE FCST DRY EXCEPT FOR THE USUAL WESTERN SNOW SHOWERS.
THE NEXT SYSTEM OF NOTE LOOKS TO ARRIVE ON TUESDAY. AS THE HIGH
SLIDES OFF TO OUR EAST...WE SHOULD SEE WARM AIR FLOOD BACK INTO
THE REGION MAKING FOR MAINLY A RAIN EVENT WITH THE APPROACHING
FRONT. HOWEVER WE WILL HAVE TO WATCH FOR THE POTENTIAL OF A WINTRY
MIX AT THE ONSET IF THE PRECIP ARRIVES EARLY ENOUGH TUESDAY.
IT WILL COOL DOWN ONCE AGAIN BEHIND THE FRONT FOR MID
WEEK...BEFORE MILDER AIR STARTS TO MOVE BACK TOWARD THE REGION
LATE IN THE WEEK. THE PATTERN IS COMPLICATED HOWEVER WITH MODELS
HINTING AT AN UPPER BLOCK DEVELOPING OVER SOUTHERN CANADA. THIS
COULD SUPPRESS THE WARM AIR AND KEEP US JUST COLD ENOUGH THAT ANY
MOISTURE THAT HEADS OUR WAY COULD CREATE THE POTENTIAL FOR SNOW OR
A WINTRY MIX BY WEEK`S END.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
NO MAJOR CHANGES MADE TO 12Z TAF PACKAGE.
EARLIER DISCUSSION BELOW.
A LOW PRES SYSTEM TRACKING NORTH OF PA THROUGH THE GRT LKS WILL
DRAG A WEAK COLD FRONT ACROSS THE REGION THIS MORNING. MOST OF
THE LOWER CIGS WILL BE ACROSS THE WESTERN PART OF THE STATE.
OTHER THAN BFD AND JST...AND TIMES AOO...MOST AREAS WILL BE VFR
TODAY. SOME HINTS THAT CONDITIONS COULD BE MVFR AT TIMES BY LATE
AFTERNOON AND THIS COULD LINGER INTO TONIGHT...AS A WEAK WAVE
FORMS ON THE FRONT AND LIFTS NE.
HINTS THAT THIS COULD OCCUR AGAIN LATE FRIDAY...AND AGAIN
LATER ON SAT. THE SYSTEM FOR FRIDAY NIGHT WOULD MOST LIKELY
BE THE STRONGER ONE...COMPARED TO THE ONE LATE THU...OR ON
SAT.
COLDER AND MORE WIND FOR THE WEEKEND.
IMPROVING CONDITIONS FOR MONDAY...AS HIGH PRESSURE BUILDS
NORTHWARD.
SOME SHOWERS ON TUE...AS NEXT COLD FRONT MOVES TOWARD THE
AREA.
OUTLOOK...
SAT...SHSN/REDUCED VSBYS POSSIBLE W MTNS...ESP LATE.
SUN...BREEZY WITH SHSN POSSIBLE...MAINLY W MTNS.
MON...NO SIG WX EXPECTED.
TUE...SHRASN/REDUCED CIGS POSSIBLE...MAINLY W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...MARTIN
AREA FORECAST DISCUSSION...UPDATED
NWS BLACKSBURG VA
450 PM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT CROSSES THE REGION TONIGHT...FOLLOWED BY A STRONGER
ARCTIC COLD FRONT SATURDAY NIGHT. MEANWHILE...AN AREA OF LOW
PRESSURE WILL FORM ALONG THE FIRST BOUNDARY AND MOVE OFF THE
CAROLINA COAST BEFORE TURNING NORTH LATER SATURDAY. HIGH PRESSURE
ARRIVES SUNDAY NIGHT BEFORE ANOTHER COLD FRONT ENTERS THE
APPALACHIANS LATE MONDAY NIGHT.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 445 PM EST FRIDAY...
SENDING A QUICK UPDATE TO PUSH SNOWFALL EAST FASTER BASED ON
CURRENT OBS SHOWING SNOW ALREADY OVER MUCH OF SE WVA. ALSO UPPED
POPS TO REFLECT CURRENT COVERAGE WITH MORE CATEGORICAL FLAVOR OVER
THE WEST EARLY THIS EVENING. LOWERED CURRENT TEMPS WITH READINGS
QUICKLY FALLING FROM THE 40S TO NEAR FREEZING IN AN HOUR OR SO
OVER THE FAR WEST.
AS OF 330 PM EST FRIDAY...
A SHARPENING AND DEEPENING UPPER LEVEL TROF WILL
TAKE SHAPE ACROSS THE EASTERN UNITED STATES BRINING A RETURN TO
WINTER LIKE WEATHER. THE FIRST SHORT WAVE PIVOTS ACROSS THE EASTERN
OHIO VALLEY THEN LIFTS NORTHEAST TONIGHT. THIS PUSHES A COLD FRONT
THROUGH OUR AREA TONIGHT...EXITING THE SOUTHEAST PORTION OF THE
FORECAST AREA BY 02Z.
AS THE BEST LIFT MOVES AWAY FROM OUR AREA...PRECIP CHANCES WILL BE
GREATEST DURING THE EVENING HOURS. BEFORE WE LOSE THE LIFT...STRONG
CAA BEHIND THE SFC FRONT WILL CHANGE THE PRECIP TO SNOW OR A
RAIN/SNOW MIX IN THE MOUNTAINS. ACROSS THE WESTERN SLOPES...CAA AND
A NORTHWEST FLOW WILL SQUEEZE OUT UPSLOPE SNOW SHOWERS WELL INTO THE
NIGHT.
A MORE POTENT UPPER LEVEL WAVE PUSHING INTO THE CENTRAL PLAINS THIS
AFTERNOON WILL MOVE ACROSS THE CAROLINAS ON SATURDAY...WHICH SPINS
UP A SFC LOW OFF THE NC COAST. MODELS SHOW GOOD 700MB FRONTOGENESIS
FORMING IN ADVANCE OF THIS SYSTEM...SUGGESTING HEAVY BANDS OF PRECIP
WILL DEVELOP ACROSS NC AND IN THE EASTERN PORTION OF OUR FORECAST
AREA. FORECAST SOUNDINGS SUGGEST TEMPS ALOFT WILL SUPPORT SNOW...OR
A RAIN/SNOW MIX. DYNAMIC COOLING WITH THIS STRONG SYSTEM SHOULD KEEP
MOST OF THE PRECIP IN THE FORM OF SNOW. SOME FACTORS THAT COULD
LIMIT SNOW ACCUMULATION ARE THE WARM GROUND TEMPS AND THE FACT OUR
AREA WILL BE ON THE NORTHWEST SIDE OF THE BEST LIFT. IN FACT...THE
GFS IS AN OUTLIER WITH THE WESTERN EXTENT OF THE PRCIP SHIELD...AND
A SLIGHTLY MORE EASTERN TRACK...AS SHOWN BY THE 12Z ECMWF KEEPS THE
HEAVIEST AMOUNTS OUT OF FORECAST AREA.
STILL...WILL ISSUE WINTER WEATHER ADVISORIES FOR THE NC MOUNTAINS
FOR NEAR ADVISORY CRITERIA IN HIGHER ELEVATIONS...BUT LESS AMOUNTS
TO THE EAST AND NO HEADLINES.
AS THE SFC LOW DEEPENS...WINDS WILL INCREASE FROM THE NORTHWEST AND
UPSLOPE SNOW SHOWERS WILL AGAIN DEVELOP ACROSS SOUTHEAST WEST
VIRGINIA.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 408 PM EST FRIDAY...
LOW PRESSURE MOVING ALONG TONIGHT`S COLD FRONT SATURDAY WILL BE
MOVING FAR ENOUGH AWAY FROM OUR AREA TO PULL ITS PRECIP SHIELD
JUST OUT OF OUR EXTREME EASTERN COUNTIES EARLY SATURDAY NIGHT.
DEPENDING UPON HOW DEEP THIS LOW TURNS OUT TO BE...SNOW MAY HOLD
ALONG THESE COUNTIES A LITTLE LONGER THAN CURRENTLY FORECAST.
ARCTIC BOUNDARY ARRIVING WILL GENERATE UPSLOPE SNOW SHOWERS AGAIN
SATURDAY NIGHT...WITH ENOUGH MOISTURE TO POSSIBLY DELIVER SOME
SNOW SHOWERS INTO THE NEW RIVER VALLEY. AS AN UPPER LEVEL
DISTURBANCE LEAVES AFTER MIDNIGHT INTO SUNDAY MORNING...MOISTURE
DRIES OUT RAPIDLY AND SNOW SHOWERS WILL BE MORE CONFINED TO SE
WEST VA. EXPECTING THE GREATEST COVERAGE OF SNOW SHOWERS AROUND
6Z/1AM SUNDAY. UP TO 4" MAY FALL ACROSS WESTERN GREENBRIER WITH AN
INCH OR TWO DOWN INTO BLF AND SIMILAR LOCATIONS ABOVE 2500 FEET.
WIND DIRECTION SHOULD ALSO DELIVER SOME SNOW BANDS INTO NW NC
WHERE AN INCH OR LESS IS EXPECTED BUT 2" ABOVE 3500 FEET. AS
CLOUDS ARE REMOVED AND BETTER MIXING OCCURS ADVISORY CRITERIA WIND
GUSTS ARE LIKELY ASHE/WATAUGA/GRAYSON AND A HIGH WIND WATCH MAY
NEED TO BE CONSIDERED. AGAIN...MOS TEMPS LOOK TOO WARM WITH A
SHALLOW ARCTIC AIRMASS SO USED SOME OF THE COLDER VALUES. SINGLE
DIGITS DEWPOINTS AND RELAXING OF WIND WILL ALLOW DECOUPLING
AND WIDESPREAD LOWS IN THE MIDDLE TEENS SUNDAY NIGHT. UPPER
TROUGH LEAVES MONDAY WITH QUICK WAA...BUT A LOW MOVING INTO THE
GREAT LAKES WILL DRAG A FRONT AND PRECIP ACROSS THE REGION LATE
MONDAY NIGHT...WITH EVAP COOLING LIKELY PRODUCING A QUICK SHOT OF
SLEET AND MAYBE SOME FREEZING RAIN ACROSS GREENBRIER INITIALLY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 350 PM EST FRIDAY...
HIGH PRESSURE DRIFTS OFF THE SOUTHEAST COAST ALLOWING A COLD FRONT
TO PASS OVER THE REGION TUESDAY. A WINTRY MIX OF RAIN/SNOW/SLEET MAY
STILL BE FALLING ACROSS THE GREENBRIER VALLEY AND ALLEGHANY
HIGHLANDS TUESDAY MORNING. TEMPERATURES WARM BY MID MORNING WITH ALL
PRECIPITATION FALLING AS RAIN. RAIN EXITS QUICKLY BY THE EVENING RUSH
HOUR WITH WINDS INCREASING FROM THE WEST. WE WILL SEE CLEARING
CONDITIONS FROM EAST TO WEST OVERNIGHT WITH SOME LINGERING
CLOUDS/UPSLOPE SNOW SHOWERS INTO EARLY WEDNESDAY MORNING. TRAJECTORIES
ARE NOT FAVORABLE FOR SIGNIFICANT UPSLOPE ACCUMULATIONS. MOISTURE
COULD BE SHALLOW BY THE TIME THE COLDEST AIR ARRIVES TO JUST HAVE
SPOTTY FREEZING DRIZZLE/SCATTERED FLURRIES.
STRONG SOUTHWEST FLOW AHEAD OF THE FRONT MAY CREATE SOME WIND
PROBLEMS ACROSS THE BLUEFIELD/RICHLANDS AREA TUESDAY MORNING. AS THE
JET TRANSFERS EAST OF THE APPALACHIANS...STRONG WINDS MIXING TO THE
SURFACE COULD PRODUCE ADVISORY GUSTS FOR THE REST OF THE AREA. WILL
CONTINUE TO HIGHLIGHT IN THE HWO. STRONG AND GUSTY WINDS WILL ALSO
FOLLOW THE FRONT WITH ANY ADVISORY GUSTS REMAINING ALONG THE HIGHER
RIDGES ALONG THE BLUE RIDGE.
HIGH PRESSURE WILL MOVE OVER THE REGION WEDNESDAY AFTERNOON WITH
BREEZY CONDITIONS RELAXING BY THE EVENING. A WARM FRONT IS EXPECTED
TO OVERRUN THIS SURFACE HIGH PRESSURE ON THURSDAY. LIGHT
PRECIPITATION COULD START FALLING AS EARLY AS THURSDAY AFTERNOON (12Z
GFS) OR START EARLY FRIDAY MORNING (12Z ECMWF). AS PRECIPITATION
FALLS INTO THIS RIDGE...AN INSITU WEDGE WILL DEVELOP WITH A
PERSISTENT EASTERLY FLOW THROUGH THE DAY FRIDAY. DESPITE THE TIMING
DIFFERENCES...EVAPORATIVE COOLING IN BOTH MODELS OVERNIGHT SUPPORT
FROZEN PRECIPITATION THURSDAY NIGHT INTO FRIDAY. GFS FORECAST
SOUNDING SUGGESTING FREEZING RAIN. WITH UNCERTAINTY LOOMING LARGE
THIS FAR OUT...WILL KEEP GRIDS SIMPLE WITH RAIN/SNOW. GFS IS ALSO
BREAKING THE WEDGE QUICKLY FRIDAY MORNING. KEPT THE WEDGE IN LONGER
AND COULD SEE IT BREAKING FRIDAY NIGHT VIA PRESSURE FALLS OVER THE
OHIO VALLEY PER THE ECMWF.
TEMPERATURES WILL HOVER AROUND NORMAL ON TUESDAY. CHILLY HIGH
PRESSURE WILL TREND AFTERNOON TEMPERATURES BELOW NORMAL WEDNESDAY
AND THURSDAY. TEMPERATURES WILL CONTINUE TO TREND COLDER FRIDAY WITH
A WET COLD AIR DAMMING EVENT EXPECTED.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AS OF 110 PM EST FRIDAY...
COLD FRONT AND ASSOCIATED PCPN POISED TO ENTER THE AREA FROM THE
NW ATTM. RUC AND WRF SEEM TO HAVE SOMEWHAT OF A HANDLE ON THIS SO
WILL USE SHORT TERM EXTRAPOLATION FOR ARRIVAL OF PCPN AND FOLLOW
MESO MODEL GUIDANCE THEREAFTER. BASED ON UPSTREAM CIGS/VSBYS...DO
NOT EXPECT ANYTHING LOWER THAN MVFR WITH THE PCPN. TYPICAL
DOWNSLOPING EAST OF THE BLUE RIDGE SHOULD HELP KEEP THINGS VFR FOR
KROA...KLYH... AND KDAN. WEST OF THE BLUE RIDGE...KLWB AND KBLF
WILL TRANSITION TO AN UPSLOPING PCPN -SHSN EVENT THIS EVENING AND
CONTINUE THROUGH TOMORROW. STILL LOOKING FOR MVFR CIGS/VSBYS AND
EXPECT -SHSN TO BE LIGHT.
KDAN IS INTERESTING FOR THE LATTER PORTION OF THE TAF PERIOD. LIFT
DEVELOPING ON THE BACK SIDE OF THE DEEPENING LOW SLIDING OFF THE COAST
WILL BEGIN TO DEVELOP A PRECIPITATION SHIELD. IT CURRENTLY LOOKS LIKE
KDAN WILL BE ON THE EDGE OF THIS AND WILL KEEP SOME BORDERLINE VFR CIGS
IN AFTER 12Z ALONG WITH SOME PCPN.
LOW LEVEL WINDS DO NOT RAMP UP UNTIL LATER IN THE DAY SATURDAY IN RESPONSE
TO DEEPENING OF COASTAL LOW SO DO NOT EXPECT SIGNIFICANT WINDS TO HAMPER
AVIATION INTERESTS THROUGH THIS TAF PERIOD.
EXTENDED AVIATION DISCUSSION...
REASONING THROUGH THE EXTENDED PORTION STILL APPLIES AS PER PREVIOUS
DISCUSSION:
HIGH PRESSURE AND VFR CONDITIONS WILL RETURN TO THE MOUNTAINS BY
SUNDAY. GOOD FLYING WEATHER SHOULD PREVAIL UNTIL TUESDAY...WHEN A
NEW COLD FRONT COULD BRING SHOWERS WITH GUSTY WINDS ALONG WITH
MVFR/IFR CEILINGS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST SUNDAY FOR NCZ001-018.
WV...NONE.
&&
$$
SYNOPSIS...AMS/KM
NEAR TERM...AMS/JH/PH
SHORT TERM...KM
LONG TERM...RCS
AVIATION...AMS/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
416 PM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT CROSSES THE REGION TONIGHT...FOLLOWED BY A STRONGER
ARCTIC COLD FRONT SATURDAY NIGHT. MEANWHILE...AN AREA OF LOW
PRESSURE WILL FORM ALONG THE FIRST BOUNDARY AND MOVE OFF THE
CAROLINA COAST BEFORE TURNING NORTH LATER SATURDAY. HIGH PRESSURE
ARRIVES SUNDAY NIGHT BEFORE ANOTHER COLD FRONT ENTERS THE
APPALACHIANS LATE MONDAY NIGHT.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 330 PM EST FRIDAY...
A SHARPENING AND DEEPENING UPPER LEVEL TROF WILL
TAKE SHAPE ACROSS THE EASTERN UNITED STATES BRINING A RETURN TO
WINTER LIKE WEATHER. THE FIRST SHORT WAVE PIVOTS ACROSS THE EASTERN
OHIO VALLEY THEN LIFTS NORTHEAST TONIGHT. THIS PUSHES A COLD FRONT
THROUGH OUR AREA TONIGHT...EXITING THE SOUTHEAST PORTION OF THE
FORECAST AREA BY 02Z.
AS THE BEST LIFT MOVES AWAY FROM OUR AREA...PRECIP CHANCES WILL BE
GREATEST DURING THE EVENING HOURS. BEFORE WE LOSE THE LIFT...STRONG
CAA BEHIND THE SFC FRONT WILL CHANGE THE PRECIP TO SNOW OR A
RAIN/SNOW MIX IN THE MOUNTAINS. ACROSS THE WESTERN SLOPES...CAA AND
A NORTHWEST FLOW WILL SQUEEZE OUT UPSLOPE SNOW SHOWERS WELL INTO THE
NIGHT.
A MORE POTENT UPPER LEVEL WAVE PUSHING INTO THE CENTRAL PLAINS THIS
AFTERNOON WILL MOVE ACROSS THE CAROLINAS ON SATURDAY...WHICH SPINS
UP A SFC LOW OFF THE NC COAST. MODELS SHOW GOOD 700MB FRONTOGENESIS
FORMING IN ADVANCE OF THIS SYSTEM...SUGGESTING HEAVY BANDS OF PRECIP
WILL DEVELOP ACROSS NC AND IN THE EASTERN PORTION OF OUR FORECAST
AREA. FORECAST SOUNDINGS SUGGEST TEMPS ALOFT WILL SUPPORT SNOW...OR
A RAIN/SNOW MIX. DYNAMIC COOLING WITH THIS STRONG SYSTEM SHOULD KEEP
MOST OF THE PRECIP IN THE FORM OF SNOW. SOME FACTORS THAT COULD
LIMIT SNOW ACCUMULATION ARE THE WARM GROUND TEMPS AND THE FACT OUR
AREA WILL BE ON THE NORTHWEST SIDE OF THE BEST LIFT. IN FACT...THE
GFS IS AN OUTLIER WITH THE WESTERN EXTENT OF THE PRCIP SHIELD...AND
A SLIGHTLY MORE EASTERN TRACK...AS SHOWN BY THE 12Z ECMWF KEEPS THE
HEAVIEST AMOUNTS OUT OF FORECAST AREA.
STILL...WILL ISSUE WINTER WEATHER ADVISORIES FOR THE NC MOUNTAINS
FOR NEAR ADVISORY CRITERIA IN HIGHER ELEVATIONS...BUT LESS AMOUNTS
TO THE EAST AND NO HEADLINES.
AS THE SFC LOW DEEPENS...WINDS WILL INCREASE FROM THE NORTHWEST AND
UPSLOPE SNOW SHOWERS WILL AGAIN DEVELOP ACROSS SOUTHEAST WEST
VIRGINIA.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 408 PM EST FRIDAY...
LOW PRESSURE MOVING ALONG TONIGHT`S COLD FRONT SATURDAY WILL BE
MOVING FAR ENOUGH AWAY FROM OUR AREA TO PULL ITS PRECIP SHIELD
JUST OUT OF OUR EXTREME EASTERN COUNTIES EARLY SATURDAY NIGHT.
DEPENDING UPON HOW DEEP THIS LOW TURNS OUT TO BE...SNOW MAY HOLD
ALONG THESE COUNTIES A LITTLE LONGER THAN CURRENTLY FORECAST.
ARCTIC BOUNDARY ARRIVING WILL GENERATE UPSLOPE SNOW SHOWERS AGAIN
SATURDAY NIGHT...WITH ENOUGH MOISTURE TO POSSIBLY DELIVER SOME
SNOW SHOWERS INTO THE NEW RIVER VALLEY. AS AN UPPER LEVEL
DISTURBANCE LEAVES AFTER MIDNIGHT INTO SUNDAY MORNING...MOISTURE
DRIES OUT RAPIDLY AND SNOW SHOWERS WILL BE MORE CONFINED TO SE
WEST VA. EXPECTING THE GREATEST COVERAGE OF SNOW SHOWERS AROUND
6Z/1AM SUNDAY. UP TO 4" MAY FALL ACROSS WESTERN GREENBRIER WITH AN
INCH OR TWO DOWN INTO BLF AND SIMILAR LOCATIONS ABOVE 2500 FEET.
WIND DIRECTION SHOULD ALSO DELIVER SOME SNOW BANDS INTO NW NC
WHERE AN INCH OR LESS IS EXPECTED BUT 2" ABOVE 3500 FEET. AS
CLOUDS ARE REMOVED AND BETTER MIXING OCCURS ADVISORY CRITERIA WIND
GUSTS ARE LIKELY ASHE/WATAUGA/GRAYSON AND A HIGH WIND WATCH MAY
NEED TO BE CONSIDERED. AGAIN...MOS TEMPS LOOK TOO WARM WITH A
SHALLOW ARCTIC AIRMASS SO USED SOME OF THE COLDER VALUES. SINGLE
DIGITS DEWPOINTS AND RELAXING OF WIND WILL ALLOW DECOUPLING
AND WIDESPREAD LOWS IN THE MIDDLE TEENS SUNDAY NIGHT. UPPER
TROUGH LEAVES MONDAY WITH QUICK WAA...BUT A LOW MOVING INTO THE
GREAT LAKES WILL DRAG A FRONT AND PRECIP ACROSS THE REGION LATE
MONDAY NIGHT...WITH EVAP COOLING LIKELY PRODUCING A QUICK SHOT OF
SLEET AND MAYBE SOME FREEZING RAIN ACROSS GREENBRIER INITIALLY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 350 PM EST FRIDAY...
HIGH PRESSURE DRIFTS OFF THE SOUTHEAST COAST ALLOWING A COLD FRONT
TO PASS OVER THE REGION TUESDAY. A WINTRY MIX OF RAIN/SNOW/SLEET MAY
STILL BE FALLING ACROSS THE GREENBRIER VALLEY AND ALLEGHANY
HIGHLANDS TUESDAY MORNING. TEMPERATURES WARM BY MID MORNING WITH ALL
PRECIPITATION FALLING AS RAIN. RAIN EXITS QUICKLY BY THE EVENING RUSH
HOUR WITH WINDS INCREASING FROM THE WEST. WE WILL SEE CLEARING
CONDITIONS FROM EAST TO WEST OVERNIGHT WITH SOME LINGERING
CLOUDS/UPSLOPE SNOW SHOWERS INTO EARLY WEDNESDAY MORNING. TRAJECTORIES
ARE NOT FAVORABLE FOR SIGNIFICANT UPSLOPE ACCUMULATIONS. MOISTURE
COULD BE SHALLOW BY THE TIME THE COLDEST AIR ARRIVES TO JUST HAVE
SPOTTY FREEZING DRIZZLE/SCATTERED FLURRIES.
STRONG SOUTHWEST FLOW AHEAD OF THE FRONT MAY CREATE SOME WIND
PROBLEMS ACROSS THE BLUEFIELD/RICHLANDS AREA TUESDAY MORNING. AS THE
JET TRANSFERS EAST OF THE APPALACHIANS...STRONG WINDS MIXING TO THE
SURFACE COULD PRODUCE ADVISORY GUSTS FOR THE REST OF THE AREA. WILL
CONTINUE TO HIGHLIGHT IN THE HWO. STRONG AND GUSTY WINDS WILL ALSO
FOLLOW THE FRONT WITH ANY ADVISORY GUSTS REMAINING ALONG THE HIGHER
RIDGES ALONG THE BLUE RIDGE.
HIGH PRESSURE WILL MOVE OVER THE REGION WEDNESDAY AFTERNOON WITH
BREEZY CONDITIONS RELAXING BY THE EVENING. A WARM FRONT IS EXPECTED
TO OVERRUN THIS SURFACE HIGH PRESSURE ON THURSDAY. LIGHT
PRECIPITATION COULD START FALLING AS EARLY AS THURSDAY AFTERNOON (12Z
GFS) OR START EARLY FRIDAY MORNING (12Z ECMWF). AS PRECIPITATION
FALLS INTO THIS RIDGE...AN INSITU WEDGE WILL DEVELOP WITH A
PERSISTENT EASTERLY FLOW THROUGH THE DAY FRIDAY. DESPITE THE TIMING
DIFFERENCES...EVAPORATIVE COOLING IN BOTH MODELS OVERNIGHT SUPPORT
FROZEN PRECIPITATION THURSDAY NIGHT INTO FRIDAY. GFS FORECAST
SOUNDING SUGGESTING FREEZING RAIN. WITH UNCERTAINTY LOOMING LARGE
THIS FAR OUT...WILL KEEP GRIDS SIMPLE WITH RAIN/SNOW. GFS IS ALSO
BREAKING THE WEDGE QUICKLY FRIDAY MORNING. KEPT THE WEDGE IN LONGER
AND COULD SEE IT BREAKING FRIDAY NIGHT VIA PRESSURE FALLS OVER THE
OHIO VALLEY PER THE ECMWF.
TEMPERATURES WILL HOVER AROUND NORMAL ON TUESDAY. CHILLY HIGH
PRESSURE WILL TREND AFTERNOON TEMPERATURES BELOW NORMAL WEDNESDAY
AND THURSDAY. TEMPERATURES WILL CONTINUE TO TREND COLDER FRIDAY WITH
A WET COLD AIR DAMMING EVENT EXPECTED.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AS OF 110 PM EST FRIDAY...
COLD FRONT AND ASSOCIATED PCPN POISED TO ENTER THE AREA FROM THE
NW ATTM. RUC AND WRF SEEM TO HAVE SOMEWHAT OF A HANDLE ON THIS SO
WILL USE SHORT TERM EXTRAPOLATION FOR ARRIVAL OF PCPN AND FOLLOW
MESO MODEL GUIDANCE THEREAFTER. BASED ON UPSTREAM CIGS/VSBYS...DO
NOT EXPECT ANYTHING LOWER THAN MVFR WITH THE PCPN. TYPICAL
DOWNSLOPING EAST OF THE BLUE RIDGE SHOULD HELP KEEP THINGS VFR FOR
KROA...KLYH... AND KDAN. WEST OF THE BLUE RIDGE...KLWB AND KBLF
WILL TRANSITION TO AN UPSLOPING PCPN -SHSN EVENT THIS EVENING AND
CONTINUE THROUGH TOMORROW. STILL LOOKING FOR MVFR CIGS/VSBYS AND
EXPECT -SHSN TO BE LIGHT.
KDAN IS INTERESTING FOR THE LATTER PORTION OF THE TAF PERIOD. LIFT
DEVELOPING ON THE BACK SIDE OF THE DEEPENING LOW SLIDING OFF THE COAST
WILL BEGIN TO DEVELOP A PRECIPITATION SHIELD. IT CURRENTLY LOOKS LIKE
KDAN WILL BE ON THE EDGE OF THIS AND WILL KEEP SOME BORDERLINE VFR CIGS
IN AFTER 12Z ALONG WITH SOME PCPN.
LOW LEVEL WINDS DO NOT RAMP UP UNTIL LATER IN THE DAY SATURDAY IN RESPONSE
TO DEEPENING OF COASTAL LOW SO DO NOT EXPECT SIGNIFICANT WINDS TO HAMPER
AVIATION INTERESTS THROUGH THIS TAF PERIOD.
EXTENDED AVIATION DISCUSSION...
REASONING THROUGH THE EXTENDED PORTION STILL APPLIES AS PER PREVIOUS
DISCUSSION:
HIGH PRESSURE AND VFR CONDITIONS WILL RETURN TO THE MOUNTAINS BY
SUNDAY. GOOD FLYING WEATHER SHOULD PREVAIL UNTIL TUESDAY...WHEN A
NEW COLD FRONT COULD BRING SHOWERS WITH GUSTY WINDS ALONG WITH
MVFR/IFR CEILINGS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST SUNDAY FOR NCZ001-018.
WV...NONE.
&&
$$
SYNOPSIS...KM
NEAR TERM...AMS/PH
SHORT TERM...KM
LONG TERM...RCS
AVIATION...AMS/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
108 PM EST FRI FEB 15 2013
.SYNOPSIS...
A COLD FRONT EXTENDED FROM A LOW OVER THE GREAT LAKES INTO THE
SOUTHERN PLAINS. ANOTHER LOW ALONG THIS FRONT...OVER THE
TENNESSEE VALLEY WILL MOVE EAST ACROSS THE MID ATLANTIC REGION
TODAY THEN OFF THE EAST COAST ON SATURDAY. HIGH PRESSURE WILL
COVER THE EASTERN UNITED STATES SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM EST FRIDAY...
UPDATED THE FORECAST TO REFLECT THE SLOWER ARRIVAL OF THE INITIAL
SFC FRONT...WHICH EARLY THIS AFTERNOON WAS JUST ENTERING THE FAR
NORTHERN PART OF OUR FORECAST AREA. THIS SLOWER ARRIVAL HAS
ALLOWED TEMPERATURES TO CLIMB MUCH HIGHER THAN MODEL GUIDANCE AND
PREVIOUS FORECASTS. HAVE PUSHED HIGHS TODAY WELL INTO THE 60S EAST
OF THE BLUE RIDGE.
PER THE HIGH RES ARW MODEL...RAIN APPROACHING THE WESTERN PORTION
OF THE FORECAST AREA WILL OVERSPREAD THE MOUNTAINS BETWEEN 21Z-00Z
TONIGHT...ONCE THE FRONT COMES THROUGH AND WINDS BECOME
NORTHWEST...MOUNTAINS WILL GO BACK INTO UPSLOPE SNOW SHOWERS.
EXPECT MUCH OF THE AREA WEST OF A HOT SPRINGS TO BOONE LINE WILL
CHANGE OVER TO SNOW SHOWERS EARLY THIS EVENING. SNOW ACCUMULATIONS
WILL REMAIN VERY LIGHT IN ALL BUT SOUTHEAST WEST VIRGINIA. EVEN IN
THE FAVORED AREAS OF WESTERN GREENBRIER COUNTY NOT EXPECTING
SNOWFALL OF MORE THAN ONE INCH EVERY 12 HOURS. WILL HOLD OFF ON
ANY ADVISORY FOR NOW.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EST FRIDAY...
WILL START SATURDAY MORNING OFF WITH SNOW SHOWERS ALREADY ONGOING
ACROSS OUR TYPICAL NORTHWEST WIND UPSLOPE AREAS FROM SOUTHEAST WEST
VIRGINIA THROUGH THE NORTH CAROLINA MOUNTAINS. SNOW SHOWER ACTIVITY
WILL BECOME AMPLIFIED FOR A FEW HOURS DURING THE AFTERNOON AS A DEEP
SHORTWAVE ROUNDS THE BASE OF THE LARGER LONG WAVE UPPER LEVEL TROUGH
STRETCHING FROM THE GREAT LAKES THROUGH THE GULF OF MEXICO.
HOWEVER...THIS SHORTWAVE WILL MOVE TO THE EAST QUICKLY...SPREADING
SNOW SHOWER ACTIVITY ACROSS THE VIRGINIA AND NORTH CAROLINA
PIEDMONTS BY EVENING AS A DEEP SURFACE LOW DEVELOPS OFF THE NORTH
CAROLINA COAST.
WITH THE PASSAGE OF THIS SHORTWAVE TROUGH...WE CAN EXPECT THE LARGER
LONGWAVE TROUGH TO GRADUALLY SHIFT EAST THROUGH SATURDAY NIGHT AND
SUNDAY...LEADING TO AN OVERALL DECREASE IN MOUNTAIN SNOW SHOWERS AS
SURFACE HIGH PRESSURE MOVES EAST ALONG THE GULF COAST. SNOW SHOWER
ACTIVITY IS EXPECTED TO END FOR OUR AREA BY SUNDAY AFTERNOON...WITH
CLEARING SKIES AREAWIDE. REGARDLESS...THE UPPER TROUGH WILL STILL BE
CLOSE ENOUGH TO KEEP TEMPERATURES ON THE CHILLY SIDE...RANGING FROM
THE UPPER 20S IN SOUTHEAST WEST VIRGINIA TO THE LOW 40S IN NORTH
CENTRAL NORTH CAROLINA FOR SUNDAY AFTERNOON HIGHS.
HIGH PRESSURE WILL SHIFT EAST SUNDAY NIGHT...ALLOWING WINDS TO
BECOME INCREASINGLY SOUTHERLY. THE SOUTHERLY FLOW WILL ALLOW WARMER
AIR TO BUILD INTO THE AREA...LEADING TO A SIGNIFICANT WARMUP FOR
MONDAY WITH AFTERNOON HIGHS REACHING INTO THE 40S AND LOW 50S. WIND
SPEEDS WILL INCREASE ACROSS THE MOUNTAINS MONDAY NIGHT AS ANOTHER
STRONG COLD FRONT APPROACHES THE AREA...AND MAY SEE ANOTHER ROUND OF
STRONG GUSTS DEVELOP ACROSS THE MOUNTAIN EMPIRE THROUGH THE NORTH
CAROLINA MOUNTAINS DURING THE OVERNIGHT HOURS. AS THE COLD FRONT
NEARS MONDAY NIGHT...SHOWER ACTIVITY WILL BEGIN TO ENTER THE AREA.
DESPITE THE WARMER AIR BUILDING ALOFT...BELIEVE SURFACE TEMPERATURES
WILL TAKE LONGER TO REBOUND...LEADING TO RAIN SHOWERS MIXED WITH
SLEET OR SNOW AT TIMES FOR THE MOUNTAINS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 400 AM EST FRIDAY...
A COLD FRONT WILL SWING ACROSS THE REGION TUESDAY...WITH A MIX OF
RAIN AND WINTRY PRECIPITATION CONTINUING ACROSS THE MOUNTAINS FOR
TUESDAY MORNING...THEN SHOWERS FOR THE ENTIRE AREA TUESDAY
AFTERNOON. THE FRONT MAY GET STUCK ALONG THE EAST COAST TUESDAY
NIGHT AS A LOW PRESSURE SYSTEM DEVELOPS ACROSS THE SOUTHEASTERN USA.
THIS FRONT WILL THEN JOG OUT TO SEA ON WEDNESDAY WITH A CHILLY HIGH
PRESSURE SYSTEM SETTLING OVER THE REGION THROUGH THURSDAY. POCKETS
OF FREEZING RAIN MAY AGAIN DEVELOP IN SOME MOUNTAIN VALLEYS FRIDAY
MORNING AS THE NEXT FRONTAL SYSTEM SWINGS ACROSS THE REGION.
TEMPERATURES WILL RUN ABOVE NORMAL MONDAY AND TUESDAY. TEMPERATURES
WILL DIP BELOW NORMAL ON WEDNESDAY...THEN REBOUND TOWARD NORMAL ON
THURSDAY.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 110 PM EST FRIDAY...
COLD FRONT AND ASSOCIATED PCPN POISED TO ENTER THE AREA FROM THE
NW ATTM. RUC AND WRF SEEM TO HAVE SOMEWHAT OF A HANDLE ON THIS SO
WILL USE SHORT TERM EXTRAPOLATION FOR ARRIVAL OF PCPN AND FOLLOW
MESO MODEL GUIDANCE THEREAFTER. BASED ON UPSTREAM CIGS/VSBYS...DO
NOT EXPECT ANYTHING LOWER THAN MVFR WITH THE PCPN. TYPICAL
DOWNSLOPING EAST OF THE BLUE RIDGE SHOULD HELP KEEP THINGS VFR FOR
KROA...KLYH... AND KDAN. WEST OF THE BLUE RIDGE...KLWB AND KBLF
WILL TRANSITION TO AN UPSLOPING PCPN -SHSN EVENT THIS EVENING AND
CONTINUE THROUGH TOMORROW. STILL LOOKING FOR MVFR CIGS/VSBYS AND
EXPECT -SHSN TO BE LIGHT.
KDAN IS INTERESTING FOR THE LATTER PORTION OF THE TAF PERIOD. LIFT
DEVELOPING ON THE BACK SIDE OF THE DEEPENING LOW SLIDING OFF THE COAST
WILL BEGIN TO DEVELOP A PRECIPITATION SHIELD. IT CURRENTLY LOOKS LIKE
KDAN WILL BE ON THE EDGE OF THIS AND WILL KEEP SOME BORDERLINE VFR CIGS
IN AFTER 12Z ALONG WITH SOME PCPN.
LOW LEVEL WINDS DO NOT RAMP UP UNTIL LATER IN THE DAY SATURDAY IN RESPONSE
TO DEEPENING OF COASTAL LOW SO DO NOT EXPECT SIGNIFICANT WINDS TO HAMPER
AVIATION INTERESTS THROUGH THIS TAF PERIOD.
...EXTENDED AVIATION DISCUSSION...
REASONING THROUGH THE EXTENDED PORTION STILL APPLIES AS PER PREVIOUS
DISCUSSION:
HIGH PRESSURE AND VFR CONDITIONS WILL RETURN TO THE MOUNTAINS BY
SUNDAY. GOOD FLYING WEATHER SHOULD PREVAIL UNTIL TUESDAY...WHEN A
NEW COLD FRONT COULD BRING SHOWERS WITH GUSTY WINDS ALONG WITH
MVFR/IFR CEILINGS.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/PH
SHORT TERM...NF
LONG TERM...NF/RCS
AVIATION...AMS/NF
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
602 PM CST SAT FEB 16 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SYNOPSIS...
ISSUED AT 223 PM CST SAT FEB 16 2013
MODERATING TEMPS WITH SOME LIGHT TO MODERATE PRECIPITATION MONDAY
NIGHT AND TUESDAY. STILL PLENTY OF QUESTIONS ABOUT THE NEXT SYSTEM
EXPECTED TO ARRIVE LATE IN THE WEEK.
UPR FLOW ACRS NOAM WL START OUT WITH A BROAD RIDGE OVER THE ERN
PAC/WRN NOAM...ALBEIT WITH STG SHRTWV RIGHT IN THE MIDDLE OF THE
RIDGE POSN. A DEEP TROF WAS OVER ERN NOAM...WITH RIDGING OVER THE
WRN ATL. THE SHRTWV NOW IN THE WRN RIDGE POSN AND ITS SUCCESSOR WL
BOTH DIG PROGRESSIVELY FARTHER W...EVENTUALLY PULLING THE MEAN
TROF POSN BACK INTO THE WESTERN CONUS BY MID-WK. MEANWHILE...THE
DOWNSTREAM PATTERN OVER THE ATL WL BREAK DOWN INTO A COMPLEX
BLOCKING REGIME. THE BLOCKING WL EVOLVE WWD WITH TIME...
RESULTING IN A SPLIT FLOW ACRS MUCH OF THE CONUS BY NEXT WEEKEND.
THE TWO MAJOR SHRTWVS WORKING ACRS THE CONUS DURING THE PERIOD WL
BOTH SUPPORT STG CYCLONES. THE CHANGING UPR PATTERN AND PASSAGE OF
THE CYCLONES WL TAKE TEMPS ON A ROLLERCOASTER RIDE DURING THE
PERIOD. THEY/LL START OUT COLD...QUICKLY WARM EARLY IN THE WEEK...
DROP BACK TO BLO NORMAL MID-WEEK...THEN SETTLE BACK CLOSER TO
NORMAL AS THE FLOW SETTLES INTO SPLIT REGIME. GIVEN THE 2 SIG
SYSTEMS LIKELY TO IMPACT THE AREA...PCPN AMNTS WL PROBABLY END UP
AOA NORMAL.
&&
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 223 PM CST SAT FEB 16 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE RIDGE STRETCHING FROM TEXAS TO ONTARIO THIS AFTERNOON.
STEEPENING LOW LEVEL LAPSE RATES AND FLOW OFF SUPERIOR CONTRIBUTED
TO A WIDESPREAD DIURNAL CU FIELD...WHICH SPREAD SOUTH ACROSS MUCH
OF THE CWA BY EARLY THIS AFTERNOON. LAKE EFFECT SNOW SHOWERS
REMAINED CONFINED TO NORTHERN VILAS COUNTY AND POINTS NORTH AND
VSBYS IN THIS AREA SUGGEST ONLY MINOR ACCUMS AT BEST. PRETTY QUIET
UPSTREAM AS WELL. FGEN INDUCED BAND OF CLOUDS AND LIGHT SNOW OVER
THE PLAINS IS SLIDING SE WHILE SKY CONDITIONS ARE CLEARING OVER
MINNESOTA. CLOUD TRENDS AND TEMPS ARE THE MAIN FORECAST CONCERNS
IN THE SHORT TERM.
TONIGHT...SURFACE HIGH PRESSURE TO MOVE ACROSS THE REGION AND
THIS SHOULD RESULT IN LOW LEVEL FLOW BECOMING LIGHT THIS EVENING.
ANTICIPATING STRATO-CU TO RAPIDLY DIMINISH WITH LOSS OF DAYTIME
HEATING EARLY THIS EVENING...EXCEPT OVER NORTH-CENTRAL WISCONSIN
WHERE IT SHOULD TAKE A FEW HOURS LONGER. AS A RESULT...EXPECT SKY
CONDITIONS TO BECOME CLEAR TO MOSTLY CLEAR ACROSS THE REGION BY
LATE THIS EVENING. STRATUS UPSTREAM THIS MORNING BENEATH THE RIDGE
AXIS SEEMED ALIGNED WITH A LOW LEVEL THERMAL GRADIENT. THIS
GRADIENT DOES NOT MOVE MUCH TONIGHT...SO AM NOT EXPECTING CLOUDS
TO REFORM BENEATH THE SURFACE HIGH. TEMPS LAST NIGHT FELL INTO THE
TEENS BELOW ZERO OVER N-C WISCONSIN. SHOULD HAVE LIGHTER WINDS IN
THE BOUNDARY LAYER AND THE PWAT MINIMUM OVERHEAD...SO HAVE DROPPED
TEMPS FROM THE PREVIOUS FORECAST.
SUNDAY...HIGH PRESSURE MOVES EAST OF THE REGION AND RETURN FLOW
WILL PUSH A WARM FRONT INTO THE NORTHERN MISSISSIPPI VALLEY BY THE
AFTERNOON. THOUGH MID AND HIGH CLOUDS WILL BE INCREASING THROUGH
THE DAY...DEEPER MOISTURE WILL STAY WELL OFF TO THE NORTHWEST OVER
NORTHERN MINNESOTA AND SOUTH-CENTRAL CANADA. HIGHS WILL BE
CONSIDERABLY WARMER THAN TODAYS READINGS...AND MOSTLY RANGE FROM
THE LOWER TO MIDDLE 20S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 223 PM CST SAT FEB 16 2013
WAA ON THE BACK SIDE OF DEPARTING RIDGE WL KICK INTO HIGH GEAR
SUN NGT. THE STRONGEST ISENT LIFT AND BEST CHC AT SATURATION WL BE
ACRS THE N. WENT WITH CHC POPS THERE...AND KEPT THE S DRY. EXPECT
EVENING MINS THEN RISING TEMPS.
COMPLEX STORM SYSTEM DRIVEN BY PHASING SHRTWVS WL BE ORGANIZING
AS IT CROSSES THE AREA MON...THEN DEEPEN JUST OFF TO OUR E MON NGT
INTO TUE. RAISED POPS AS FORCING LOOKS FAIRLY STG. BUT MOISTURE WL
BE LIMITED...ESP INITIALLY. THAT WL PROBABLY RESULT IN ANOTHER
EVENT WITH MESSY MIX OF SN/DZ/FZDZ DEPENDING ON WHETHER SUFFICIENT
MID-LVL MOISTURE IS PRESENT AT ANY TIME TO SEED THE LOWER CLDS FM
ABV. MODEL FCST SOUNDINGS SUGGEST LOWER-LEVELS OVER E-C WI COULD
BRIEFLY BE WARM ENOUGH FOR JUST RAIN MON AFTN EVEN IF MOISTURE IS
DEEP AT THAT TIME. WENT WITH MAINLY SN/FZDZ ACRS THE NW AND RA/SN
IN THE SE ON MON. E-C WI COULD CERTAINLY SEE DZ RATHER THAN
RAIN... BUT WANTED TO AVOID HAVING TOO MANY PCPN TYPES IN THE
FCST.
PCPN SHOULD CHG TO SNOW MON NGT...WITH SHSN ON THE BACK SIDE OF
THE SYSTEM CONTG INTO TUE. UPPED POPS AS UPR TROF WL BE SHARPENING
RIGHT ACRS THE AREA DURING THAT TIME. THINKING RIGHT NOW IS THAT
THIS WL BE A 1-3 INCH EVENT...WITH THE HIGHER TOTALS IN THE NE.
LAKE-EFFECT OFF LAKE SUPERIOR COULD BOOST TOTALS EVEN FURTHER OVER
THE SNOWBELT...THOUGH THAT DEPENDS ON EXACT TRAJECTORIES SO WON/T
GET TOO SPECIFIC WITH THAT YET.
A BREAK FM THE SIG PCPN THEN EXPECTED WED INTO THU AS UPR RIDGE
SHARPENS ACRS THE AREA. STG...COLD...VERY DRY LOW-LEVEL
ANTICYCLONE WL BE RIDGING SWD INTO THE RGN FM THE HUDSON BAY AREA.
LOW-LEVEL WINDS WL VEER ARND TO THE E...AND ALTHOUGH THE UPSTREAM
AIR WL BE VERY DRY AND INVERSION HEIGHTS WL BE LOW...WL PROBABLY
GET SOME LAKE FLURRIES INTO E-C WI.
STILL A LOT OF QUESTIONS ABOUT THE SYSTEM HEADING INTO THE AREA
DURING THE LATTER PART OF THE WEEK. DON/T LIKE THAT THE SYSTEM WL
BE DRIVING INTO A DOWNSTREAM BLOCK AND HAVE VERY DRY AIR FEEDING
INTO IT FM THE E AT LOW-LEVELS. THAT/S A CLASSIC LATE WINTER/EARLY
SPRING FCST PROBLEM HERE...AND IT TYPICALLY RESULTS IN A CONSTANT
DELAYING OF THE ONSET OF PCPN...AND OFTEN A REDUCTION IN PCPN
TOTALS. ON THE OTHER HAND...IF SYSTEM CAN GET PCPN INTO THE
AREA...DOWNSTREAM BLOCKING WL CAUSE IT TO SLOW TO A CRAWL...AND
RESULT IN A LONG-DURATION EVENT.
FEELING RIGHT NOW IS THAT THIS IS A SYSTEM THAT WL HAVE IT/S
GREATEST IMPACT OUT IN THE PLAINS. MAX SNOWS WL PROBABLY END UP IN
THE SW PART OF THE FCST AREA...AND THEY WILL PROBABLY BE
CONSIDERABLY LESS THAN WHAT FALLS TO OUR SW. AT THIS POINT...WAS
CONTENT WITH INITIALIZATION GRIDS THAT NEVER WENT BEYOND LIKELY
POPS. CERTAINLY PLENTY OF TIME FOR LATER SHIFTS TO ADJUST FCST.
WL CONT TO MENTION SYSTEM IN THE HWO...BUT DON/T PLAN ON PLAYING
THIS UP AS A BIG STORM.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
DIURNALLY DRIVEN CLOUDS WILL QUICKLY ERODE THIS EVENING...WITH
LAKE EFFECT CLOUDS ALSO DIMINISHING AS RIDGE MOVES OVER AREA. VFR
CONDITIONS EXPECTED THROUGH THE PERIOD...WITH ONLY AN INCREASE OF
MID LEVEL CLOUDS AS WARMER AIR WORKS NORTH INTO THE REGION ON
SUNDAY.
TE
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
531 PM CST SAT FEB 16 2013
.SHORT TERM...THROUGH TUESDAY NIGHT
326 PM CST SAT FEB 16 2013
MUCH OF THE TIME TODAY WAS SPENT WORKING ON MONDAY INTO TUESDAY.
IMPACTS LOOK TO BE MINIMAL AS MAIN PRECIPITATION REGION LOOKS TO
ADVECT IN JUST EAST OF THE FORECAST AREA.
CLOUDS HAVE BEEN A TOUGH FORECAST AS OF LATE...AND TONIGHT THEY
COULD HAVE A HUGE IMPACT ON LOW TEMPERATURES. CURRENT GOES
SATELLITE IMAGERY SHOWING CLOUDS EXPANDING IN WRN MN WEST OF THE
SURFACE RIDGE AXIS FROM KINL TO KALO. MAINLY CUMULUS FIELDS
ARE AFFECTING THE FORECAST AREA WITH THOSE EXPECTED TO DISSIPATE
BY LATE AFTERNOON. SURFACE OBSERVATIONS SHOWING A STATIONARY FRONT
LOCATED FROM ABOUT KFSD-KDSM WITH WARM AIR TO THE SOUTHWEST AND
CONVERGENT FLOW INTO NE IA.
GOES WATER VAPOR SHOWING THE MONDAY S/WV WELL NOW COMING ONTO THE
WEST COAST WITH THE NRN ENERGY OVER BRITISH COLUMBIA AND THE
16.19Z RAP INDICATING A TROPOPAUSE FOLD TO 400MB INTO THE OR
COAST REPRESENTING THE SRN ENERGY THAT IS FORECAST TO DIG INTO THE
CENTRAL U.S. KUIL WASHINGTON RAOB HAD A 150M/12HR HEIGHT FALL THIS
MORNING AHEAD OF THIS POTENT SHORTWAVE TROUGH.
HAVE LOWERED THE LOW TONIGHT ACROSS CENTRAL WI AS THE SURFACE
RIDGE WILL BE RIGHT OVERHEAD MOST OF THE NIGHT AND CLOUDS ARE
FORECAST TO REMAIN MINIMAL. HAVE DROPPED LOWS 5-7F THERE TONIGHT
FROM PREVIOUS FORECAST. CLOUDS ARE TOUGH THOUGH AND AM THINKING
TWO AREAS COULD DEVELOP STRATUS...CURRENT HEAVY CUMULUS AREA OVER
NRN WI AND CONVERGENT BOUNDARY ACROSS IA. THE NRN WI AREA COULD
EXPAND OVER NRN FORECAST AREA LATE AND CLOUDS WILL ALSO SPREAD IN
FROM THE SW. THUS...LOW CONFIDENCE IN FORECAST CLOUDS AND LOWS
TONIGHT...BUT FORECASTING THE CENTRAL FORECAST AREA TO REMAIN
MOSTLY CLEAR.
WARM ADVECTION TO KICK IN SUNDAY AND PEAK SUNDAY NIGHT WITH
WARMING OCCURRING INTO MONDAY WEATHER SYSTEM. 16.12Z MODEL
CONSENSUS IS TO STILL DEVELOP THE NRN CYCLONE THE MOST...NORTH OF
THE GREAT LAKES...WITH THE SRN ENERGY CAUSING WEAK CYCLOGENESIS
ALONG THE FRONTAL BOUNDARY AS IT PASSES TO THE SE OF THE FORECAST
AREA. SOME SPREAD STILL REMAINS IN THE GUIDANCE. THE 16.12Z NAM
REMAINS CONSISTENT WITH IT/S PREVIOUS RUNS OF THE DRY OUTLIER. THE
16.12Z CANADIAN GLOBAL GEM STILL INSISTS ON A WET 0.30 INCHES
AREA-WIDE WITH THIS SYSTEM /AND HIGHS IN THE 40S/. STILL PREFER THE
CONSISTENT ECMWF/GFS RUNS ON THE OUTCOME FOR THIS SYSTEM. IT
APPEARS THE MAIN MOISTURE AXIS WILL ONLY GRAZE THE ERN FORECAST
AREA FROM CENTRAL WI TO SWRN WI...A STEP EAST FROM PREVIOUS MODEL
RUNS. THIS SAME AREA WILL SEE THE DEEPEST SURFACE-BASED SATURATION
COME IN MONDAY MORNING /KOVS 0-2 KM/...WITH THE LAYER MORE SHALLOW
FURTHER TO THE NW /KEAU 1KM/. NW OF THE SURFACE WAVE...WOULD THINK
A BIT OF ENHANCEMENT IN THE DEFORMATION WILL OCCUR AND HAVE KEPT
HIGHEST PRECIPITATION CHANCES IN THAT SWRN-CENTRAL WI
AREA...TAPERING LOWER TO THE NORTHWEST.
IT APPEARS DEEP SATURATION TO COLDER THAN -10C TO GET ICE GROWTH WILL
BE TROUBLESOME/SPOTTY OR JUST PLAIN HARD TO FORECAST WITH THIS
SYSTEM. THE Q-G FORCING IS MODERATE ALOFT AND WEAKER IN THE LOW
LEVELS PROVIDING OVERALL A WEAK BUT PRESENT LIFT SIGNAL. BUT
REVIEWING MODEL SOUNDINGS FROM THE 16.09Z SREF AND 16.12Z NAM/GFS
THERE IS CONSISTENT STRUGGLES WITH SATURATION NOTED...AND THUS
HAVE GONE WITH A MAJORITY OF LIQUID IN THE FORECAST UNTIL THE COLD
FRONT MOVES IN LATER MONDAY WITH VERY STRONG COLD ADVECTION TO DRIVE
THE ICE PROCESS AND SNOW CONVERSION. THIS SATURATION STRUGGLE AWAY
FROM THE SURFACE WAVE IS ALSO WHY PRECIPITATION CHANCES ARENT
HIGHER FOR THIS FORECAST.
MONDAY MORNING WILL SEE THE MOISTURE INCREASE AND SURFACE TEMPERATURES
WARMING TO NEAR OR ABOVE FREEZING IN THE AFTERNOON. THIS WILL
CAUSE A FZDZ POSSIBILITY MAINLY IN THE MORNING IF THE LAYER CAN
PRECIPITATE...PROBABLY VERY LIGHT AMOUNTS AROUND 0.01-0.02 INCHES
TO PROVIDE A LIGHT GLAZE AFTER COMMUTE TIME. MANY AREAS SOUTH OF
I-90 WILL WARM TO ABOVE FREEZING BY MID-DAY...ESPECIALLY CLOSE TO
THE MOIST AXIS SO IMPACTS WOULD BE MINIMAL THERE...OR AT LEAST
SHORT LIVED. HAVE KEPT FZDZ STILL POSSIBLE FOR POINTS WITH AIR
TEMPERATURES OF 35F OR COLDER AS ROADS MAY STILL BE SLOWER TO
RECOVER TO ABOVE FREEZING.
THE NORTHERN AND WESTERN AREAS COULD SEE FZDZ PERIODICALLY MONDAY
THROUGH THE DAY...POSSIBLE MIXING WITH SNOW AS SATURATION OCCURS
IN A PATCHY WAY. THE COLD FRONT WILL SWEEP IN WITH VERY STRONG
COLD ADVECTION CONVERTING ALL LIGHT LIQUID PRECIPITATION TO SNOW.
WITH THE COLD ADVECTION STRONG...LAPSE RATES IN THE LOWEST 1 KM
ARE QUITE STEEP AND WILL PROMOTE WIND GUSTS IN THE 25 TO 35 MPH
RANGE LATE MONDAY AND OVERNIGHT. HAVE INCREASED THE WINDS WITH
THIS FORECAST BASED ON 16.12Z NAM/GFS BLEND.
OVERALL...COMFORT REMAINS LOW ON THIS SYSTEM /I HAVE MORE
CONFIDENCE IN THE THU-FRI SNOW/ BUT MY FEELING IS THAT THE IMPACTS
WILL BE MINOR. DO NOT FEEL A NEED FOR A HEADLINE ON THIS SYSTEM AS
THE LIQUID AMOUNTS LOOK TO BE PRETTY LIGHT. IN THE DEFORMATION
AREA TEMPERATURES WOULD BE WARMEST AND MAINLY RAIN WOULD FALL. BUT
THERE ARE SOME HINTS THAT UP TO A TENTH OF PRECIPITATION COULD
FALL MONDAY AWAY FROM THE MOISTURE AXIS /KEAU SREF MEAN GIVES 0.07
OF FZDZ/ SO IT IS STILL A SYSTEM TO WATCH.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
326 PM CST SAT FEB 16 2013
THE FOCUS REMAINS ON THE INCREASINGLY ADVERTISED LATE WEEK SYSTEM
AND THE DEGREE OF IMPACT IT WILL HAVE ON THE UPPER MIDWEST. LEADING
UP TO THAT FEATURE...WEDNESDAY LOOKS TO BE A TRANSITION DAY WITH
MORNING COLD ADVECTION AS A SURFACE HIGH AND UPPER LEVEL RIDGE AXIS
REMAINS TO THE WEST OF THE FORECAST AREA. A COLD DAY ON TAP AS
MORNING LOWS IN THE SINGLE DIGITS BELOW/ABOVE ZERO LOOK TO RISE INTO
ONLY THE TEENS. THE RIDGE IS THEN EXPECTED TO BUILD ACROSS BY
WEDNESDAY NIGHT...LEADING TO RETURN SOUTHERLY FLOW. A WESTERN CONUS
TROUGH THEN DIGS AND MOVES EAST...EJECTING THE MAIN SHORTWAVE
TROUGH OUT OF THE COLORADO ROCKIES BY 12Z THURSDAY. SURFACE LOW
DEEPENS RAPIDLY ACROSS THE CENTRAL PLAINS THURSDAY...LIFTING
TOWARD THE AREA.
THE 16.12Z GFS ENSEMBLE REMAINS CLOSELY PACKED WITH A LOW TRACK
ALONG A KANSAS CITY TO NORTHERN ILLINOIS LINE THURSDAY NIGHT INTO
FRIDAY AFTERNOON. THE 16.12Z ECMWF TOOK A STEP NORTHWEST WITH ITS
SURFACE LOW TRACK AND THE 16.12Z GEM AND FIM REMAIN THE SOUTHERLY
OUTLIERS. THE GFS SEEMS TO BE A GOOD COMPROMISE. EARLIER TIMING
ISSUES APPEAR TO BE RESOLVED FOR NOW. YESTERDAY/S CONCERNS ABOUT THE
FILLING UPPER LEVEL TROUGH / SURFACE LOW AND ITS IMPACT WERE MUTED
SLIGHTLY SINCE THE 16.12Z GFS...ECMWF AND FIM CAME IN A BIT
STRONGER. HOWEVER...500 MB HEIGHT STANDARDIZED ANOMALIES STILL RISE
FROM -3.5 ACROSS THE CENTRAL PLAINS...TO AROUND -0.5 BY 12Z FRIDAY
WHICH SUGGESTS A WEAKENING TREND AND THE SYSTEM NOT NEARLY AS WOUND
UP AS IT MAY BE IN THE CENTRAL PLAINS.
PRECIPITATION WOULD OVERSPREAD THE AREA DURING THE AFTERNOON
THURSDAY...WITH THE MAIN WARM ADVECTIVE WING SWINGING THROUGH
THURSDAY NIGHT AND OVERNIGHT FRIDAY. THIS WOULD BE WHEN THE HIGHEST
SNOW RATES OCCUR. AS THE SURFACE LOW THEN MOVES NEARBY...WRAP AROUND
/ DEFORMATION BANDING SNOW WOULD LINGER THROUGHOUT FRIDAY. SOUNDINGS
STILL POINT TO AN ALL SNOW EVENT WITH THE WARMEST AIR REMAINING
SOUTH OF THE AREA.
THE MODEL CONSISTENCY AND RUN-TO-RUN SIMILARITIES REMAIN VERY ABOVE
AVERAGE AND REMARKABLE FOR IT STILL BEING 6 DAYS OUT. GIVEN THE
FEATURE IS CURRENTLY OVER THE DATA SPARSE NORTHERN PACIFIC...THERE
CERTAINLY WILL BE FINE-TUNE DETAILS TO ESTABLISH. PRECIPITATION
AMOUNTS TOOK A STEP UP IN THE LATEST ROUND OF GUIDANCE THOUGH STILL
REMAIN BETWEEN 0.7 TO 1.0 INCH. CONFIDENCE CONTINUES TO GROW IN A
WARNING LEVEL EVENT WITH WIDESPREAD 6 TO 10 INCH AMOUNTS IF THE
CURRENT AND PAST SOLUTIONS INDEED VERIFY. THE BIG PICTURE IS THAT
THOSE WITH INTERESTS AND TRAVEL CONCERNS LATE NEXT WEEK SHOULD
CONTINUE TO MONITOR AND FOR NOW...HAVE CONTINUED TO PUSH HIGHER
PRECIPITATION CHANCES THURSDAY NIGHT...AND TRENDED FRIDAY HIGHER AS
WELL SINCE IF THE SYSTEM DOES SLOW DOWN / FILL IN THEN THERE WOULD
CERTAINLY BE LINGERING DEFORMATION BANDING SNOW ACROSS MUCH OF THE
AREA. THE PROLONGED DURATION / THURSDAY NIGHT THROUGH LATE FRIDAY
NIGHT / COULD PRESENT SOME CHALLENGES FOR TRAVELERS AND ROAD CREWS
AS WELL.
&&
.AVIATION...TONIGHT AND SUNDAY
531 PM CST SAT FEB 16 2013
CLEAR SKIES WILL DOMINATE THIS EVENING AT BOTH TAF SITES WITH HIGH
PRESSURE FIRMLY IN CONTROL. AFTER MIDNIGHT AND INTO EARLY
SUNDAY...INCREASING VFR STRATUS CLOUDS SEEN OVER WESTERN
MINNESOTA ARE EXPECTED TO MOVE ACROSS THE TAF SITES...ASSOCIATED
WITH A LOW PRESSURE SYSTEM OVER THE PLAINS GRADUALLY SHIFTING
EAST. LOOK FOR THE STRATUS TO PERSIST MUCH OF SUNDAY AT
KLSE...THOUGH THE BACK EDGE SHOULD WORK EAST OUT OF KRST DURING
THE AFTERNOON. IN ADDITION TO THE INCREASE OF CLOUDS...EXPECT
SOUTHEAST WINDS TO GRADUALLY INCREASE THROUGH SUNDAY. GUSTS OF 15
TO 25 KT ARE POSSIBLE DURING THE AFTERNOON ON SUNDAY...AIDED BY
DAYTIME MIXING...WITH THE HIGHEST GUSTS AT KRST WHERE THE PRESSURE
GRADIENT IS TIGHTEST AND MIXING IS GREATEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
151 PM CST SAT FEB 16 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...TAYLOR
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
319 PM CST FRI FEB 15 2013
.SHORT TERM...THROUGH MONDAY NIGHT
319 PM CST FRI FEB 15 2013
BENIGN WEATHER THROUGH THE WEEKEND LEADS INTO MONDAYS WEATHER
SYSTEM WHICH WILL NEED TO BE WATCHED FOR CHANGES.
MUCH LESS CLOUD ACROSS THE AREA TODAY THAN FORECAST WITH MIXING
NOT DEEP ENOUGH TO FORM MUCH STRATOCUMULUS EXCEPT OVER
NORTHCENTRAL WI. LONGWAVE TROUGH AXIS CONTINUES EASTWARD PROGRESS
WITH LAST OF SHORTWAVE TROUGH ENERGY COMING THROUGH TONIGHT AND
EARLY SATURDAY. LATEST RAP AND WATER VAPOR HAS THIS BROAD
CIRCULATION AXIS FROM KINL-KLBF...AND SURFACE LOW PRESSURE IN
EASTERN NEB. CLOUD COVER OVER NWRN MN MOVING TOWARD THE AREA WILL
ARRIVE THIS EVENING FOR A CLOUD PERIOD INTO SATURDAY MORNING. NOT
TO CONFIDENT ON THE COVERAGE OF THIS CLOUD COMING IN...IT MAY BE
MORE IN AREAS. HAVE LEFT A MENTION OF FLURRIES IN THIS WEAKLY
LIFTED AIR MASS THROUGH NOON SATURDAY.
AGGRESSIVE RIDGE BUILDING THEN TAKES PLACE LATER SATURDAY AND
SUNDAY. UPSTREAM RAOB HEIGHT RISES SEEN ACROSS WRN CANADA WITH
THIS PROGRESSIVE HIGHER AMPLITUDE RIDGE. HAVE COOLED THE LOW
TEMPERATURES SUNDAY MORNING OVER CENTRAL WI WITH NEARLY CALM WINDS
AND LITTLE CLOUD UNDER LOW-LEVEL RIDGING. THESE ARE BELOW MOS
GUIDANCE BY ABOUT 5-7F. WARM ADVECTION WILL BEGIN TO RAISE
TEMPERATURES SUNDAY AND THE FORCING DOES NOT SEEM SUFFICIENT TO
CREATE PRECIPITATION PER CONSENSUS 15.12Z MODEL GUIDANCE.
HOWEVER...THE WARM ADVECTION AND THERMAL RIBBON LIFTING ACROSS THE
AREA WILL CREATE AN ARC OF CLOUDS ORIENTED NW-SE TO SHIFT NEWRD
ACROSS THE AREA. HAVE INCREASED SKY COVER A BIT FOR SUNDAY...SOME
FLURRIES MAY BE POSSIBLE BUT HAVE NOT INCLUDED THEM IN THE
FORECAST.
FAIRLY INTERESTING TROUGH TO SHIFT INTO THE AREA MONDAY. THE
TROUGH IS CURRENTLY IN THE ERN PACIFIC APPROACHING 47N/140W PER
GOES WATER VAPOR. MODEL GUIDANCE CONSENSUS FROM 15.12Z IS THAT
THERE WILL NRN AND SRN ENERGY IN THIS TROUGH. THE SRN PIECE OF
ENERGY IS HANDLED DIFFERENTLY BY THE LATEST GUIDANCE. THE 15.12Z
NAM/SREF DEVELOP ONLY A WEAK CYCLONE VIA THE SRN ENERGY...WHILE THE
GEM GLOBAL AND 15.00Z FIM MODEL ARE AGGRESSIVE WITH THE CYCLONE
DEEPENING IT ALONG A KANSAS CITY TO MILWAUKEE TRACK...AND DROPPING
A 4-8 INCH SNOW BAND ACROSS WI. 15.12Z ECMWF/GFS ARE SIMILAR AND
OFFER A COMPROMISE BETWEEN THE TWO CAMPS WITH THE CYCLONE
DEEPENING LATER...INTO MICHIGAN. HAVE GONE WITH THIS COMPROMISE ON
TIMING AND INTENSITY.
MONDAY WILL SEE A GULF SURGE OF MOISTURE IN THE SOUTHERLY FLOW...
DEEPENING A SURFACE-BASED LAYER TO OVER 1 KM DEEP. THIS WILL BE
PRE-FRONTAL IN THE SOUTHERLY FLOW AND WITHOUT DEEP CLOUD AND
ICE...BUT ISENTROPIC LIFT OF 3-5 UB/S IN THE LAYER ...DZ/FZDZ
WILL BE POSSIBLE. THE MOIST TONGUE IS MAINLY IN WI AND EAST AND
THAT IS WHERE DZ/FZDZ CHANCES WILL BE BEST. TEMPERATURES WILL BE
WARMING MONDAY WITH ABOVE FREEZING HIGHS AROUND I-90 AND SOUTH
EXPECTED. THUS...DZ OR RAIN SHOWERS COULD BE FREEZING IN THE EARLY
AFTERNOON IF ROADS DO NOT RESPOND TO WARMING. WITH QPFS LESS THAN
0.10 INCHES...WOULD EXPECT ONLY LIGHT ICING TO OCCUR. AS TROUGH
SHIFTS EAST LATE MONDAY AND MONDAY EVENING...A TRANSITION TO SNOW
WILL OCCUR FROM WEST TO EAST WITH SNOW AMOUNTS OF LESS THAN AN
INCH. HAVE INCREASED PRECIPITATION CHANCES OVERALL...BUT WI LOOKS
TO BE THE MAIN WEATHER AREA FOR THIS SYSTEM. THERE IS A CHANCE
THIS COULD NEED AN ADVISORY IF FREEZING PRECIPITATION LOOKS MORE
WIDESPREAD OR THE MORE AGGRESSIVE CYCLONE SOLUTION IN THE GEM
SHOULD BECOME MORE PROBABLE. THE SPREAD IN THE CYCLOGENESIS SEEN
FROM THE SRN ENERGY IN THE MODEL GUIDANCE SUGGESTS THIS IS AN
UNSTABLE SYSTEM AND COULD LEAD TO FORECAST CHANGES. WILL TAKE A
STEP UP IN OUR FORECAST VISIBILITY OF THIS SYSTEM.
.LONG TERM...TUESDAY THROUGH FRIDAY
319 PM CST FRI FEB 15 2013
ACTIVE EXTENDED PERIOD SETTING UP WITH THE FOCUS ON A SHORT ARCTIC
INTRUSION MID WEEK FOLLOWED BY THE POTENTIAL OF A WINTER STORM TO
IMPACT THE UPPER MIDWEST NEXT THURSDAY NIGHT AND FRIDAY.
GOING INTO TUESDAY...A LOT DEPENDS ON THE EVOLUTION AND PHASING OF
THE STORM SYSTEM THAT IS EXPECTED TO TRACK THROUGH MONDAY AND MONDAY
NIGHT...AND HOW MUCH ARCTIC AIR IS PULLED SOUTH IN ITS WAKE. 15.12Z
GUIDANCE SHOWS SIMILAR SOLUTIONS FOR 850 MB TEMPERATURES TO PLUMMET
AS LOW AS -15C TO -20C TUESDAY AND WEDNESDAY. STANDARDIZED
ANOMALIES FOR THIS PERIOD RANGE FROM 1 TO 1.5 BELOW NORMAL AND WITH
BROAD CYCLONIC FLOW ALOFT...IT WILL MAKE FOR A COUPLE COLD WINTER
DAYS. HIGHS IN THE TEENS AND OVERNIGHT LOWS IN THE SINGLE DIGITS
ABOVE ZERO...WITH OCCASIONAL LIGHT SNOW OR FLURRIES TUESDAY.
THE COLD AIRMASS SETS THE STAGE FOR LATER IN THE WEEK AS A WESTERN
CONUS TROUGH DEEPENS AND MOVES EAST. AS HAS BEEN ALLUDED TO IN
PREVIOUS DISCUSSIONS...THE RUN-TO-RUN AND MODEL CONSISTENCY FOR
THIS FEATURE REMAINS VERY HIGH. DETERMINISTIC MODELS STILL POINT
FOR A SURFACE LOW TRACK THROUGH THE CENTRAL PLAINS TO NORTHERN
ILLINOIS BY 12Z FRIDAY BRINGING WIDESPREAD PRECIPITATION TO THE
ENTIRE AREA WITH A CLASSIC DEFORMATION BAND OF SNOW SETTING UP.
LOOKING AT THE 15.12Z GFS ENSEMBLE...SURFACE LOW TRACK LOCATIONS
VARY FROM EASTERN IOWA...SOUTHERN WISCONSIN...AND ILLINOIS.
SIMILAR IDEAS ARE FOUND IN THE 15.00Z ECMWF ENSEMBLE. THE
STABILITY AND LACK OF SPREAD WITHIN THE NUMERICAL GUIDANCE FOR
THIS WEATHER SYSTEM ARE VERY HIGH.
ONE ISSUE THAT MAY PRECLUDE THIS FROM BEING A MORE SIGNIFICANT EVENT
IS THAT THE BOTH THE UPPER LEVEL AND SURFACE WAVES APPEAR TO BE
WEAKENING AS IT APPROACHES THE UPPER MIDWEST. 500 MB STANDARDIZED
ANOMALIES DROP FROM -2.5 ACROSS KANSAS TO BARELY BELOW NORMAL AS IT
CROSSES THE AREA. THIS IS REFLECTED IN THE SURFACE LOW PRESSURE
WHICH REMAINS AROUND 1000 MB THROUGHOUT. EARLIER RUNS SHOWED DEEPER
CYCLOGENESIS WITH 980-990 MB LOWS. THE 15.12Z ECMWF REALLY DAMPENS
OUT THE UPPER LEVEL AND SURFACE WAVE...BECOMING ALMOST OCCLUDED BY
FRIDAY AFTERNOON.
TEMPERATURE PROFILES ACROSS THE AREA CONTINUE TO SHOW AN ALL SNOW
EVENT...THOUGH THERE IS A SLIGHT WARMING TREND NOTED. IF THE
SYSTEM WERE TO DEEPEN AND WRAP UP MORE...THEN A PUSH OF WARMER AIR
COULD PRESENT A RAIN/SNOW MIX BUT RIGHT NOW THIS IS NOT THE CASE.
HAVE TRENDED PRECIPITATION CHANCES ABOVE MODEL CONSENSUS THURSDAY
NIGHT GIVEN CONTINUED EXCELLENT MODEL AGREEMENT AND THE SLOWER
TIMING OF THE SYSTEM.
ALTHOUGH IT IS A BIT TOO EARLY TO SPECULATE ON AMOUNTS...25.12Z GFS
ENSEMBLE AND 25.12Z ECMWF SHOW WIDESPREAD AMOUNTS OF 0.50 TO 0.75
INCHES OF LIQUID. SNOW RATIOS ARE NOT VERY HIGH...MOST LIKELY A BIT
BELOW CLIMATOLOGICAL VALUES /10 TO 12:1/ SO IN SHORT...WARNING
LEVEL /6 INCHES/ SNOW TOTALS COULD BE MET OR EXCEEDED ACROSS PARTS
OF THE AREA.
&&
.AVIATION...THROUGH 18Z SATURDAY
1148 AM CST FRI FEB 15 2013
LOW CONFIDENCE FORECAST ON CLOUD TRENDS TODAY INTO TOMORROW AS THE
REGION REMAINS IN NORTHWESTERLY FLOW. MAINLY JUST HIGH LEVEL CLOUD
COVER TO CURRENTLY CONTEND WITH BUT SOME OF THE SHORT TERM
GUIDANCE...SUCH AS THE 15.15Z HRRR...STILL WANT TO DEVELOP A LOW
LEVEL CUMULUS FIELD EARLY THIS AFTERNOON AND KEEP IT GOING INTO
THE EVENING. A MORE WIDESPREAD STRATUS DECK PERCHED IN NORTHWEST
MINNESOTA LOOKS LIKE IT WILL MOVE IN THIS EVENING AND SHOULD
PERSIST INTO TOMORROW MORNING. SINCE THERE IS LITTLE ON SATELLITE
AT THE MOMENT SHOWING THE CU DEVELOPING...HAVE SCALED BACK ON THE
MVFR CEILINGS FORMING THIS AFTERNOON AND PUSHED IT BACK TO WHEN
THE MORE WIDESPREAD STRATUS MOVES IN TONIGHT. WITH ANY LOW LEVEL
CLOUDS THAT DO FORM...SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE
THAT COULD BRING VISIBILITY BRIEFLY DOWN TO 1-3SM AT TIMES. WINDS
WILL REMAIN OUT OF THE NORTHWEST AT 7-15KTS THROUGHOUT THE PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
319 PM CST FRI FEB 15 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...TAYLOR/BAUMGARDT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1116 PM CST THU FEB 14 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY
237 PM CST THU FEB 14 2013
MAIN FORECAST CONCERNS FOR THE SHORT TERM PERIOD:
1. TEMPERATURE AND CLOUD TRENDS THROUGHOUT
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING JUST OFF THE WEST COAST OF THE U.S. INTO BRITISH
COLUMBIA...WHILE TROUGHING COVERED MUCH OF EASTERN CANADA INTO THE
NORTHERN PLAINS AND WESTERN GREAT LAKES REGION. COMING THROUGH THE
TROUGH WAS A SHORTWAVE TROUGH APPROACHING THE SIOUX FALLS SOUTH
DAKOTA AREA...WHILE ANOTHER SHORTWAVE WAS SEEN IN CENTRAL
SASKATCHEWAN. THE SHORTWAVE THAT AFFECTED THE AREA LAST NIGHT INTO
THIS MORNING HAS MOVED OFF INTO LOWER MICHIGAN. RADAR IMAGERY SHOWED
A FEW RAIN/SNOW SHOWERS OVER MUCH OF WISCONSIN IN THE WAKE OF THE
LOWER MICHIGAN SHORTWAVE...DUE TO CYCLONIC FLOW OF LOW LEVEL
MOISTURE AND STEEP LOW LEVEL LAPSE RATES. TO THE WEST...RADAR ALSO
SHOWS A BAND OF RAIN/SNOW FROM CENTRAL SOUTH DAKOTA INTO NORTHWEST
IOWA...ASSOCIATED WITH THE SIOUX FALLS SHORTWAVE. NORTHWEST LOW
LEVEL WINDS BETWEEN THE TWO SHORTWAVES ARE GRADUALLY BRINGING IN
COLDER AIR. SOUNDINGS AT BIS...ABR...MPX AND INL ALL HAD 850MB TEMPS
DROP 3-4C BETWEEN 00Z AND 12Z...ALL BETWEEN -7 AND -12C AS OF 12Z.
SOME DRIER AIR WAS ALSO ACCOMPANYING THE NORTHWEST WINDS...NOTED BY
SATELLITE IMAGERY SHOWING CLEARING ACROSS NORTHERN MN.
TONIGHT THROUGH SATURDAY DEFINITELY ARE GOING TO BE COLDER THAN
AS OF LATE. THE SHORTWAVE OVER CENTRAL SASKATCHEWAN COMBINED WITH
ANOTHER SHORTWAVE CURRENTLY UP IN NORTHERN MANITOBA ARE GOING TO
DIG SOUTH...CARVING OUT A DEEP TROUGH OVER THE REGION BY 00Z
SATURDAY. 850MB TEMPS FALL AS THIS TROUGH FORMS...DROPPING TO -14
TO -18C BY 18Z FRIDAY AND -16 TO -20C BY 12Z SATURDAY PER MODEL
CONSENSUS. THOSE AT 12Z SATURDAY ARE 1.5 STANDARD DEVIATIONS BELOW
NORMAL. THE ONLY MITIGATING FACTOR TO THE COLD AIR WOULD BE THE
LACK OF SNOW OVER THE SOUTHWEST HALF OF THE FORECAST AREA...WHICH
IF SOME SUN CAN OCCUR WOULD REALLY HELP TO BOOST TEMPS UP GIVEN
THE CLIMBING SUN ANGLE NOW. GENERALLY FOLLOWED A BLEND OF THE
ECMWF AND 30 DAY BIAS CORRECTED GFS GRIDDED MOS GUIDANCE DATA
SINCE THEY HAVE BEEN DOING WELL AS OF LATE FOR HIGHS. LOWS ARE
HIGHLY CONTINGENT ON CLOUD COVER. AFTER SOME CLEARING TONIGHT...
MORE LOW TO MID CLOUDS MOVE IN FROM THE NORTHWEST FOR FRIDAY AND
FRIDAY NIGHT...ASSOCIATED WITH THAT SHORTWAVE DROPPING DOWN OUT OF
MANITOBA. THESE CLOUDS COMBINED WITH A NORTHWEST BREEZE SHOULD
HELP KEEP LOWS FROM BOTTOMING OUT...THUS A BLEND OF GUIDANCE FOR
LOWS SEEMS REASONABLE.
HANDLING CLOUD COVER SATURDAY COULD BE TRICKY. A RIDGE OF HIGH
PRESSURE IS PROGGED TO BUILD INTO THE WESTERN PORTIONS OF THE
FORECAST AREA. WILL FOLLOW THE GENERAL MODEL CONSENSUS OF THE LOW
CLOUDS BREAKING UP THROUGH THE DAY...DUE TO A COMBINATION OF THE LOW
LEVEL FLOW BECOMING ANTICYCLONIC AND DAYTIME MIXING. HOWEVER...IT IS
POSSIBLE THE CLOUDS COULD HANG ON FOR MUCH OF THE DAY. THIS COMBINED
WITH 850MB TEMPS STILL ONLY BETWEEN -14C WEST TO -20C EAST AT 18Z
WILL KEEP TEMPERATURES SEASONABLY COOL.
FOR SATURDAY NIGHT AND SUNDAY...A POTENT SHORTWAVE TROUGH IS PROGGED
TO DROP INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES...FORMING
TWO DISTINCT LOW PRESSURE AREAS ACROSS THE PLAINS DURING THE DAY
SUNDAY. A SOUTHERLY LOW LEVEL JET WILL DEVELOP AHEAD OF THESE TWO
LOWS...BRINGING UP WARMER AIR. AN INCREASE OF MID AND HIGH CLOUDS
ARE LIKELY TO ACCOMPANY THIS WARM ADVECTION. SO THE QUESTION FOR
LOWS SATURDAY NIGHT IS TIMING OF WHEN THE WARM ADVECTION STARTS UP
AND MID CLOUDS MOVE IN...VERSUS THE DEPARTURE TO THE EAST OF THE
SURFACE RIDGE. OUR WISCONSIN COUNTIES HAVE THE BEST SHOT OF
FAVORABLE RADIATIONAL COOLING CONDITIONS...THUS LEANED TOWARDS THE
COLDER SIDE OF GUIDANCE THERE. TEMPERATURES SHOULD RISE FROM LATE
SATURDAY NIGHT THROUGH SUNDAY AT MOST LOCATIONS AS SOUTHERLY WINDS
INCREASE. QUESTION ON SUNDAY IS HOW WARM DO WE GET...WITH 850MB
TEMPS THAT COULD APPROACH 0C NEAR CHARLES CITY IA BY 00Z MONDAY. IT
APPEARS SUNSHINE WILL BE ON THE INCREASE WEST OF THE MS RIVER AS THE
MID CLOUD LIFTS TO THE NORTH. GIVEN THE LACK OF SNOW OVER THE
SOUTHWEST HALF OF THE FORECAST AREA...LEANED MORE TOWARDS THE
CONSISTENTLY WARM ECMWF...BRINGING HIGHS AT LEAST TO THE MID 30S
AROUND CHARLES CITY.
PRECIPITATION WISE...MUCH OF THE SHORT TERM LOOKS DRY WITH RESPECT
TO REACHING 0.01" OF LIQUID EQUIVALENT IN ANY 12 HOUR PERIOD.
FLURRIES LOOK LIKELY...HOWEVER...FOR FRIDAY AND FRIDAY NIGHT OUT OF
THOSE LOW CLOUDS SINCE THEY EXIST WITHIN THE DENDRITIC GROWTH ZONE
AND HAVE WEAK LIFT FROM THE SHORTWAVE. PREVIOUS FORECAST MENTIONED
CONCERN THAT AS THE WARM ADVECTION STARTS UP SATURDAY NIGHT THAT WE
COULD SEE SOME SNOW FALL OUT OF THE ASSOCIATED MID CLOUD DECK. THAT
STILL REMAINS A CONCERN...THOUGH THINK FLURRIES WOULD BE THE MOST
THAT GETS PRODUCED. THEN AGAIN...THESE FLURRIES MIGHT BE ABSORBED BY
LOWER LEVEL DRY AIR. FOR NOW HAVE KEPT THE FORECAST DRY FOR SATURDAY
NIGHT AND SUNDAY.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
237 PM CST THU FEB 14 2013
MAIN CONCERNS FOR THE LONG TERM PERIOD...
1. TEMPERATURES AND PRECIPITATION POTENTIAL THROUGH MONDAY
2. BRIEF ARCTIC AIR SHOT FOR MID-WEEK
3. POTENTIAL FOR A WINTER STORM TO IMPACT THE AREA LATE IN THE WEEK
VERY GOOD MODEL AGREEMENT EXISTS AMONGST THE 14.12Z
ECMWF/GFS/CANADIAN/UKMET THROUGHOUT MUCH OF THE LONG TERM PERIOD.
FOR SUNDAY NIGHT INTO MONDAY...THE TROUGHING THAT WAS COMING ACROSS
THE NORTHERN ROCKIES EVOLVES BY MONDAY EVENING INTO A FULL
LONGITUDINAL TROUGH ACROSS THE CANADIAN AND U.S. PLAINS. THIS
TROUGHING EVENTUALLY PHASES TOGETHER AS IT CROSSES THE REGION AND
HEADS INTO THE GREAT LAKES FOR TUESDAY. PRIOR TO THE PHASING...A
REALLY STRONG PUSH OF WARM AIR COMES UP AT THE REGION WITH 850MB
TEMPS BETWEEN -2C AND +4C AT 12Z MONDAY. HAVE BOOSTED HIGH
TEMPERATURES FOR MONDAY AS A RESULT...THOUGH COULD BE EVEN HIGHER AS
NOTED BY THE 14.12Z ECMWF. ALSO...MODELS CONTINUE TO TREND
FARTHER WEST WITH THE SOUTHERN LOW COMING OUT OF THE SOUTHERN
PLAINS. AS SUCH...NOW ABOUT THE EASTERN TWO THIRDS OF THE AREA IS
AFFECTED BY LIGHT PRECIPITATION FOR MONDAY AFTERNOON AND EVENING.
THUS...HAVE EXPANDED LOW PRECIPITATION CHANCES FARTHER WEST AND
RAISED THEM 5-10 PERCENT. IF TRENDS CONTINUE...THESE CHANCES WILL
NEED TO BE RAISED MORE. WITH THE WARMER TEMPERATURES TOO...MIXING
WITH OR CHANGING TO RAIN IS AN ISSUE AS WELL.
AS THE PHASED TROUGH FORMS OVER THE AREA MONDAY NIGHT AND TUESDAY...
ARCTIC AIR FLOWS INTO THE REGION. 850MB TEMPS PLUMMET TO -12 TO -14C
BY 12Z TUESDAY AND -14 TO -20C BY 12Z WEDNESDAY. THUS...A MUCH
COOLER PERIOD IS ON TAP AGAIN. CANADIAN HIGH PRESSURE BUILDING DOWN
INTO THE NORTHERN PLAINS...IN THE WAKE OF THE PHASED TROUGH...WILL
PROVIDE FOR BLUSTERY CONDITIONS. WIND CHILLS RIGHT NOW LOOK TO STAY
JUST ABOVE ADVISORY CRITERIA...BOTTOMING OUT AT MOST IN THE -15 TO
-20F RANGE WEDNESDAY MORNING.
LASTLY...ABOUT THE POTENTIAL WINTER STORM LATE IN THE WEEK. THERE IS
SURPRISINGLY CONSISTENT AND GOOD MODEL AGREEMENT AMONGST THE
ECMWF...GFS AND THEIR RESPECTIVE ENSEMBLES OF A DEEP TROUGH FORMING
OVER THE WESTERN U.S. ON WEDNESDAY. AS THIS TROUGH HEADS EAST
TOWARDS THE PLAINS...A DEEP LOW PRESSURE AREA DEVELOPS OVER THE
CENTRAL PLAINS BY THURSDAY MORNING. THERE ARE A FEW QUESTIONS FROM
HERE ON...WHICH MAY TAKE AT LEAST A FEW MORE DAYS TO ANSWER:
1. TIMING AND STRENGTH AS USUAL
2. HOW QUICK DOES THE PRECIPITATION SPREAD INTO THE AREA IF IT
INDEED AFFECTS US
3. HOW MUCH PRECIPITATION WOULD OCCUR
4. DEPENDING ON HOW MUCH THE SYSTEM WRAPS UP...MAY HAVE TO DEAL WITH
PRECIPITATION TYPE ISSUES
FOR NOW HAVE STAYED WITH A CONSENSUS APPROACH...WHICH BY THURSDAY
NIGHT YIELDS 50-60 PERCENT CHANCES OF PRECIPITATION REGION-WIDE. ALL
PRECIPITATION RIGHT NOW LOOKS TO FALL AS SNOW...WHICH COULD BE
SIGNIFICANT. SINCE THE STORM IS VERY FAR OUT IN THE FORECAST AND
JUST BEYOND THE CURRENT HWO PERIOD...HAVE KEPT THE MENTION OF THE
STORM TO THIS DISCUSSION ONLY. HOWEVER...IF TRENDS ON THIS SYSTEM
CONTINUE...LATER SHIFTS WILL NEED TO MENTION THE STORM IN THE HWO
AND IN OTHER DECISION SUPPORT SERVICES.
&&
.AVIATION...THROUGH 06Z SATURDAY
1116 PM CST THU FEB 14 2013
SKIES HAVE CLEARED AT BOTH RST AND LSE...SO THE QUESTION NOW IS
WHEN DO THE CLOUDS RETURN AND WILL THEY PRODUCE ANY FLURRIES. THE
NEXT BATCH OF CLOUDS APPEARS TO BE FORMING IN NORTHWEST MINNESOTA
AND SHOULD REACH THE AREA AROUND OR SHORTLY AFTER SUN RISE FRIDAY.
A FEW FLURRIES HAVE BEEN REPORTING UNDER THIS DECK...SO CAN NOT
RULE OUT A FEW AS THESE CLOUDS ARRIVE FRIDAY MORNING THOUGH
VISIBILITY IS EXPECTED TO STAY AT 6SM OR GREATER. CEILINGS WILL
LIKELY VARY BETWEEN VFR AND MVFR THROUGH MUCH OF FRIDAY...SO IT
IS HARD TO PIN DOWN SPECIFICS ON THE TIMING OF THESE CHANGES.
BASED ON FORECAST SOUNDINGS...IT APPEARS THAT THE SATURATED LAYER
IS MAINLY MVFR...SO WENT WITH THAT FOR CEILINGS FOR MUCH OF THE
DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 PM CST THU FEB 14 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
945 PM MST SAT FEB 16 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 144 PM MST SAT FEB 16 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH ACROSS
WESTERN US WITH ITS AXIS CENTERED ALONG THE ROCKY MOUNTAINS...AND A
LARGE SCALE TROUGH ACROSS THE EASTERN US. A SHORTWAVE TROUGH
UPSTREAM OF THE H5 RIDGE IS DEEPENING OVER THE PACIFIC NW COAST.
THE H5 RIDGE IS EXPECTED TO SHIFT EAST WITH A VERY DRY AIRMASS
MOVING OVER OUR CWA. THE SHORTWAVE TROUGH UPSTREAM WILL DIG SOUTH
TOWARDS THE GREAT BASIN OVERNIGHT AND TOWARDS THE CENTRAL ROCKIES
MIDDAY. SURFACE GRADIENT WILL INCREASE AHEAD OF AN APPROACHING COLD
FRONT WITH WINDS INCREASING ACROSS THE SOUTHERN HALF OF THE CWA
THROUGH THE DAY. A PRE-FRONTAL TROUGH AXIS WILL MOVE INTO THE
NORTHERN HALF OF THE CWA DURING THE AFTERNOON HOURS SUNDAY WITH
WINDS DECREASING ALONG AND IMMEDIATELY BEHIND THIS FEATURE. WITH
STRONG WAA AND DEEP MIXING EXPECTED WE ARE LIKELY TO SEE NEAR RECORD
HIGH TEMPERATURES IN THE MID/UPPER 60S...POSSIBLY 70F.
VERY LOW TD VALUES ARE ALSO EXPECTED BY SUNDAY AFTERNOON...WITH RH
VALUES DROPPING TO RFW CRITERIA ACROSS MOST OF THE CWA DURING THE
AFTERNOON. WE COULD SEE SINGLE DIGIT RH VALUES IN THE SOUTH AND
WEST. AT THIS TIME...I AM MOST CONFIDENT IN WIND/RH CROSSOVER SOUTH
OF I-70 WHERE I HAVE ISSUED RED FLAG WARNING. WITH THE POSSIBILITY
OF WINDS DIMINISHING ACROSS THE NORTH...I AM NOT AS CONFIDENT IN
WIND/RH CROSSOVER...SO I ISSUED A FIRE WEATHER WATCH ACROSS THE
CENTRAL AND NORTHEASTERN PARTS OF THE CWA.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 219 PM MST SAT FEB 16 2013
LONG TERM FOCUS IS ON THE LOW PRESSURE SYSTEM MOVING EAST OF THE
ROCKIES AND ACROSS THE CENTRAL HIGH PLAINS REGION WEDNESDAY NIGHT
THROUGH THURSDAY NEXT WEEK.
SUNDAY NIGHT A COLD FRONT MOVES THROUGH THE REGION WITH THE UPPER
TROUGH MOVING THROUGH THE CENTRAL ROCKIES TO MOVE ACROSS THE
CENTRAL HIGH PLAINS BY MID DAY ON MONDAY. SINCE CONDITIONS WILL BE
MOSTLY DRY...EXPECT ONLY AN INCREASE IN CLOUDS AND COOLER
TEMPERATURES WITHOUT ANY PRECIPITATION. HIGH TEMPERATURES WILL BE
ABOUT 20 DEGREES COOLER ON MONDAY THAN THEY WERE ON SUNDAY. GUSTY
NORTHWEST WINDS ARE ALSO EXPECTED DURING THE DAY BEHIND THE FRONT.
SHORT WAVE RIDGING ALOFT IS EXPECTED ON TUESDAY AND TUESDAY NIGHT
IN THE WAKE OF THE EXITING TROUGH AND PRIOR TO THE NEXT
APPROACHING LOW PRESSURE CENTER DIVING SOUTH ALONG THE WEST COAST
THAT MOVES INTO THE FAR SOUTHWEST UNITED STATES BY WEDNESDAY
MORNING. A COOL HIGH PRESSURE AREA REMAINS OVER THE NORTHERN
PLAINS AND EXTENDS INTO THE CENTRAL PLAINS THROUGH
WEDNESDAY...TRANSPORTING LOW LEVEL MOISTURE INTO THE SOUTHERN AND
CENTRAL HIGH PLAINS REGIONS WITH THE POSSIBILITY OF A LITTLE
INSTABILITY MOVING OVER THE FORECAST AREA TO PRODUCE A MIX OF RAIN
AND SNOW SHOWERS AND POSSIBLY EVEN A RUMBLE OF THUNDER LATE IN THE
DAY ON WEDNESDAY IN THE WARM SECTOR AHEAD OF THE MAIN UPPER LOW
CENTER AS IT MOVES EAST OF THE ROCKIES IN THE VICINITY OF
SOUTHEAST COLORADO. HAVE LEFT THE MENTION OF THUNDER OUT FOR NOW.
RAIN TRANSITIONS TO SNOW OVERNIGHT WEDNESDAY NIGHT AND EARLY
THURSDAY MORNING AS COLDER AIR IS BROUGHT FURTHER SOUTH ACROSS THE
HIGH PLAINS. DEPENDING UPON THE TIMING OF THE CHANGE OVER TO SNOW
AND THE AMOUNT OF MOISTURE AND INSTABILITY THAT ACTUALLY AFFECTS
THE FORECAST AREA...THERE IS THE POTENTIAL FOR A SIGNIFICANT
SNOWFALL ACROSS THE CENTRAL HIGH PLAINS REGION MAINLY ACROSS THE
NORTHEAST HALF OF THE FORECAST AREA. IT`S STILL FAR ENOUGH OUT
THAT CONFIDENCE IS A LITTLE LACKING...BUT MODEL SOLUTIONS HAVE
BEEN ADVERTISING REASONABLY SIMILAR SOLUTIONS THROUGH THE LATTER
PORTIONS OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 945 PM MST SAT FEB 16 2013
VFR THROUGH THE PERIOD AT KGLD AND KMCK. W/SW WINDS UNDER 10KTS AT
THE START OF THE PERIOD WILL REMAIN SO THROUGH 17Z OR SO BEFORE
INCREASING AND BECOMING GUSTY FROM THE SOUTHWEST BY 19Z AND
CONTINUING THROUGH 23Z OR SO. PEAK GUSTS DURING THE AFTERNOON AT
KGLD AROUND 26KTS WITH 20KTS OR SO AT KMCK. COLD FRONT MOVES IN
AROUND 03Z AT BOTH TERMINALS WITH NW WINDS GUSTING 25-30KTS
THROUGH THE REMAINDER OF THE PERIOD. LITTLE TO NO CLOUDINESS
TIL CIRRUS INCREASE FROM THE NORTHWEST BY MID TO LATE AFTERNOON
WITH MID LEVEL CLOUDS BETWEEN 10-15K FT ARRIVING TOWARD THE END OF
THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...RED FLAG WARNING FROM 11 AM MST /NOON CST/ TO 6 PM MST /7 PM
CST/ SUNDAY FOR KSZ027>029-041-042.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR KSZ003-004-013>016.
CO...RED FLAG WARNING FROM 11 AM TO 6 PM MST SUNDAY FOR COZ254.
FIRE WEATHER WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR COZ253.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...99
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1157 PM EST SAT FEB 16 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1100 PM EST Sat Feb 16 2013
Updated the forecast to adjust sky cover and temps as well as add
isld flurries to portions of southern Indiana and north central KY
in the area from Louisville to Lexington and northward. RAP
guidance has the best handle on low clouds this evening that have
been dropping southeastward through southern Indiana and portions of
north central KY. Therefore adjusted sky cover to account for these
recent trends. Also receiving some reports of flurries and even a
few snow showers in these low clouds. Don`t think any location will
see measurable precip from this shallow low level moisture, but did
insert isld flurries into the forecast for tonight. Also adjusted
temps to the HRRR model which depicts better cool/warm areas based
on the anticipated sky cover over northern sections of the forecast
area. This results in low temps in the mid to upper teens over much
of southern Indiana and central KY with locations in the Bluegrass
only falling into the upper teens and lower 20s since they will have
a longer period of mostly cloudy skies tonight.
&&
.Short Term (Now - Sunday)...
Issued at 310 PM EST Sat Feb 16 2013
An upper-level trough axis is currently passing over the forecast
area as it heads toward the east coast. With cold air advection,
temperatures struggled to rise this afternoon. Most places have
managed to at least reach the freezing mark and areas with more sun
have pushed mid 30s. As expected, snow showers developed along the
windward side of the Appalachians early this afternoon. These
showers will continue to push east with the trough and dissipate as
sunset nears.
Ridging at the surface and aloft will build across the Ohio Valley
starting tonight and shift east through the day Sunday. With the
center of the surface high passing by to our south, expect our
current breezy northwest winds to weaken and transition to westerly
for tomorrow and southerly by tomorrow night. Generally light winds
and partly cloudy skies tonight will allow temperatures to bottom
out in the mid teens to low 20s. Believe some low-level clouds will
build across at least a portion of the forecast area overnight,
which will keep some locations from reaching full radiational
cooling potential. Right now, have stretched this anticipated band
of clouds southeastward from Orange/Dubois counties in Indiana to
the Lake Cumberland region mainly after midnight, which is supported
by most hires guidance. There is some uncertainty to just how thick
the cloud deck will be, but this is where temps in the lower 20s are
likely. Of course, any shift in this cloud band will cause a shift
in temperatures as well. These clouds will quickly clear after
daybreak. A warming trend will commence tomorrow as increasing
temperatures/heights aloft, light west surface winds, and mostly
sunny skies push high temperatures to the middle 30s across the
Lexington area and to middle 40s across the Bowling Green area.
.Long Term (Sunday Night - Saturday)...
Issued at 300 PM EST Sat Feb 16 2013
Progressive longwave pattern aloft through the coming week will
provide a little bit of everything, with two main weathermakers on
Monday night and Thursday-Friday.
Modifying Canadian surface high will start to retreat east of
Kentucky on Sunday night, allowing return flow to start to develop.
However, we do expect a strong enough inversion that the effects
will be mostly aloft, so temps will still be near normal even after
leveling off by about midnight.
Monday will be unseasonably mild and breezy with the southerly flow
well established, and much of the day to warm up ahead of the
incoming precip shield. Most noticeable feature will be south winds
at a solid 20 mph with gusts in the 30s. This is below advisory
criteria but will keep the mention in the HWO. Max temps should be a
solid 10 degrees above climo. Will start to see showers ahead of the
front, with POPs ramping up in the afternoon, mainly west of I-65.
Look for a clean FROPA on Monday night, with categorical POPs and
QPF on the order of a half inch. Will be mild enough not to have
precip type issues, and stable enough to minimize any chance of
thunder. Can`t rule out some gusty showers, but even that is an
outside shot in the stable environment.
Minimal recovery in the cold advection on Tuesday as a 1040mb
Canadian high builds south toward Lake Superior. However, the
coldest air will remain bottled up in the Great Lakes and Canada,
with shortwave upper ridging over the Ohio Valley. Temps slightly
below normal, but by no means Arctic for Tue-Thu.
Next system will eject out of the southern Rockies on Thursday, but
will occlude over the Plains as a block develops along the East
Coast. The Ohio Valley will be in for stratiform warm frontal
precip, especially Thursday night where we will carry likely POPs.
Thermal profiles will be marginal, especially in our northern
counties. Expect it to be a race between the warmth and the
moisture, and confidence in the precip type forecast is quite low.
Temps will start below freezing throughout the area Thursday
morning, but it could take most of the day to saturate the column.
If precip arrives too quickly we could be looking at snow or
freezing rain, especially in the north and west. By Thursday night
it should be all rain across all but a few southern Indiana
counties. However, confidence in the precip type forecast is
currently too low to add any more value than the mention of rain or
snow, just as a heads-up to the possibility of mixed precip.
Pacific air mass will follow for the end of the week, with dry
weather and seasonable temps.
&&
.Aviation (6Z TAF Issuance)...
Issued at 1155 PM EST Sat Feb 16 2013
Sfc high pressure looks to dominate the region for this TAF period
with upper level ridging working eastward into the region through
tomorrow. The only minor TAF concern will be low VFR clouds moving
south into the SDF/LEX taf sites tonight. Although most of the cigs
are currently at low end VFR levels, some cigs upstream have dropped
to high end MVFR in isld snow showers. This looks most likely to
occur at LEX which was reporting a sct deck of 2700 ft with a snow
shower as of 4Z. High end MVFR and a snow shower could also happen
at SDF, but don`t think it`s as likely as LEX as SDF should remain
on the edge of the low cloud deck. Will monitor closely though and
amend if necessary.
A WNW wind is expected overnight probably remaining elevated around
5-7kts at SDF/LEX. Expect more westerly winds for tomorrow with
wind speeds maxing out in the 5-7 kt range during the afternoon
hours. Tomorrow evening, winds will shift to the SE ahead of the
next weather system.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJP
Long Term........RAS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1108 PM EST SAT FEB 16 2013
.Forecast Update...
Issued at 1100 PM EST Sat Feb 16 2013
Updated the forecast to adjust sky cover and temps as well as add
isld flurries to portions of southern Indiana and north central KY
in the area from Louisville to Lexington and northward. RAP
guidance has the best handle on low clouds this evening that have
been dropping southeastward through southern Indiana and portions of
north central KY. Therefore adjusted sky cover to account for these
recent trends. Also receiving some reports of flurries and even a
few snow showers in these low clouds. Don`t think any location will
see measurable precip from this shallow low level moisture, but did
insert isld flurries into the forecast for tonight. Also adjusted
temps to the HRRR model which depicts better cool/warm areas based
on the anticipated sky cover over northern sections of the forecast
area. This results in low temps in the mid to upper teens over much
of southern Indiana and central KY with locations in the Bluegrass
only falling into the upper teens and lower 20s since they will have
a longer period of mostly cloudy skies tonight.
&&
.Short Term (Now - Sunday)...
Issued at 310 PM EST Sat Feb 16 2013
An upper-level trough axis is currently passing over the forecast
area as it heads toward the east coast. With cold air advection,
temperatures struggled to rise this afternoon. Most places have
managed to at least reach the freezing mark and areas with more sun
have pushed mid 30s. As expected, snow showers developed along the
windward side of the Appalachians early this afternoon. These
showers will continue to push east with the trough and dissipate as
sunset nears.
Ridging at the surface and aloft will build across the Ohio Valley
starting tonight and shift east through the day Sunday. With the
center of the surface high passing by to our south, expect our
current breezy northwest winds to weaken and transition to westerly
for tomorrow and southerly by tomorrow night. Generally light winds
and partly cloudy skies tonight will allow temperatures to bottom
out in the mid teens to low 20s. Believe some low-level clouds will
build across at least a portion of the forecast area overnight,
which will keep some locations from reaching full radiational
cooling potential. Right now, have stretched this anticipated band
of clouds southeastward from Orange/Dubois counties in Indiana to
the Lake Cumberland region mainly after midnight, which is supported
by most hires guidance. There is some uncertainty to just how thick
the cloud deck will be, but this is where temps in the lower 20s are
likely. Of course, any shift in this cloud band will cause a shift
in temperatures as well. These clouds will quickly clear after
daybreak. A warming trend will commence tomorrow as increasing
temperatures/heights aloft, light west surface winds, and mostly
sunny skies push high temperatures to the middle 30s across the
Lexington area and to middle 40s across the Bowling Green area.
.Long Term (Sunday Night - Saturday)...
Issued at 300 PM EST Sat Feb 16 2013
Progressive longwave pattern aloft through the coming week will
provide a little bit of everything, with two main weathermakers on
Monday night and Thursday-Friday.
Modifying Canadian surface high will start to retreat east of
Kentucky on Sunday night, allowing return flow to start to develop.
However, we do expect a strong enough inversion that the effects
will be mostly aloft, so temps will still be near normal even after
leveling off by about midnight.
Monday will be unseasonably mild and breezy with the southerly flow
well established, and much of the day to warm up ahead of the
incoming precip shield. Most noticeable feature will be south winds
at a solid 20 mph with gusts in the 30s. This is below advisory
criteria but will keep the mention in the HWO. Max temps should be a
solid 10 degrees above climo. Will start to see showers ahead of the
front, with POPs ramping up in the afternoon, mainly west of I-65.
Look for a clean FROPA on Monday night, with categorical POPs and
QPF on the order of a half inch. Will be mild enough not to have
precip type issues, and stable enough to minimize any chance of
thunder. Can`t rule out some gusty showers, but even that is an
outside shot in the stable environment.
Minimal recovery in the cold advection on Tuesday as a 1040mb
Canadian high builds south toward Lake Superior. However, the
coldest air will remain bottled up in the Great Lakes and Canada,
with shortwave upper ridging over the Ohio Valley. Temps slightly
below normal, but by no means Arctic for Tue-Thu.
Next system will eject out of the southern Rockies on Thursday, but
will occlude over the Plains as a block develops along the East
Coast. The Ohio Valley will be in for stratiform warm frontal
precip, especially Thursday night where we will carry likely POPs.
Thermal profiles will be marginal, especially in our northern
counties. Expect it to be a race between the warmth and the
moisture, and confidence in the precip type forecast is quite low.
Temps will start below freezing throughout the area Thursday
morning, but it could take most of the day to saturate the column.
If precip arrives too quickly we could be looking at snow or
freezing rain, especially in the north and west. By Thursday night
it should be all rain across all but a few southern Indiana
counties. However, confidence in the precip type forecast is
currently too low to add any more value than the mention of rain or
snow, just as a heads-up to the possibility of mixed precip.
Pacific air mass will follow for the end of the week, with dry
weather and seasonable temps.
&&
.Aviation (0Z TAF Issuance)...
Issued at 615 PM EST Sat Feb 16 2013
Sfc high pressure looks to dominate the region for this TAF period
with upper level ridging working eastward into the region through
tomorrow. The only minor TAF concern will be clouds over central IN
that are progged by the NAM and RAP to move south into the SDF/LEX
taf sites tonight. Although most of the cigs up north are currently
at low end VFR levels, short range models suggests these cigs may
lower to between 2-4 kft tonight as they move into our region. The
best time for this to happen looks to be between 1Z-10Z overnight.
Still not confident that the whole cloud deck over central IN won`t
drift farther east and miss the terminals completely and not sure
how solid the deck will be after a portion of it dissipates due to
loss of afternoon instability. Therefore, went with a bkn035 deck
at this time. Will monitor closely this evening and amend if
necessary.
Wind gusts should be declining shortly with a WNW wind expected
overnight probably remaining elevated around 7kts at SDF/LEX.
Expect more westerly winds for tomorrow with wind speeds maxing out
in the 5-7 kt range during the afternoon hours.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......MJP
Long Term........RAS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
401 AM EST SUN FEB 17 2013
.SYNOPSIS...
AN UPPER TROUGH PASSES THROUGH THE REGION THIS MORNING. LOW
PRESSURE WILL RAPIDLY INTENSIFY TODAY AS IT MOVES NORTHEASTWARD.
HIGH PRESSURE BUILDS IN THIS AFTERNOON THROUGH MONDAY BEFORE A
COLD FRONT MOVES THROUGH TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY.
A WAVE OF LOW PRESSURE MAY IMPACT THE MID-ATLANTIC REGION LATE IN
THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN AREA OF LOPRES IS CURRENTLY LOCATED OFF THE NRN MID-ATLANTIC
COAST ERY THIS MRNG. AS THE COASTAL LOW DEEPENS RAPIDLY AND
TRACKS NEWD TO OFF THE NEW ENGLAND COAST TDA...THE PRESSURE
GRADIENT WILL STRENGTHEN ON THE BACKSIDE OF THE LOW. A BRISK NW
WIND GUSTING 20-30 MPH THIS MRNG WILL INCREASE TO 40 MPH THIS
AFTN.
MEANWHILE...A NEGATIVELY-TILTED TROUGH ASSOCIATED WITH AN UPPER LOW
OVER SRN QUEBEC-ONTARIO WILL PROGRESS THRU THE AREA THIS MRNG.
DPVA AHEAD OF THE UPPER TROUGH HAS PROVIDED LIFT FOR LAKE-EFFECT
SNOW SHOWERS TO MOVE SEWD FROM LAKE ERIE TO THE ALLEGHENY FRONT.
WINTER WX ADVISORY REMAINS IN EFFECT TDA FOR THE WRN SLOPES OF THE
ALLEGHENY FRONT...WHERE SNOWFALL ACCUMULATIONS OF 2-4 INCHES ARE
EXPECTED. COMBINED WITH THE GUSTY NW WINDS...TEMPORARY VSBYS OF A
QUARTER MILE OR LESS ARE POSSIBLE IN HEAVIER SNOW SHOWERS.
TYPICALLY SNOW SHOWER ACTIVITY DISSIPATES AS IT MOVES EAST OF THE
ALLEGHENY FRONT...BUT CAA WILL PROVIDE AN ENVIRONMENT CONDUCIVE FOR
CONTINUATION OF ISO TO SCT SNOW SHOWERS FARTHER DOWNSTREAM. 00Z
NAM/GFS AND LATEST RAP BUFKIT PROFILES INDICATE STEEP LAPSE RATES
BELOW H7 TDA WITH LIMITED CONVECTIVE INSTABILITY WITHIN DENDRITIC
GROWTH ZONE. THERMAL PROFILES WILL BE FAVORABLE FOR DOWNWARD
TRANSPORT OF GUSTY WINDS ALOFT IN THESE SNOW SHOWERS. ACCORDINGLY...
THERE IS A POTENTIAL FOR LOCALLY/BRIEF HEAVIER SNOW SHOWERS OR
SQUALLS THAT COULD DROPPRODUCE A QUICK LGT ACCUMULATION...LOW
VSBYS AND GUSTY WINDS. IN WAKE OF THE UPPER TROUGH PASSAGE...
EXPECT A DOWNWARD TREND IN SNOW SHOWER ACTIVITY THRUOUT THE AFTN.
ANY ISO SNOW SHOWERS THIS AFTN THOUGH WILL HAVE THE POTENTIAL TO
MIX DOWN 35-45 MPH GUSTS.
LLVL JET MOVES THRU THIS EVE. OPTED TO NOT ISSUE A WIND ADVISORY
FOR THE HIGHER RIDGES AND IN NRN MD. ALTHOUGH WINDS JUST ABOVE THE
SFC WILL BE CLOSE TO 40 KT...CAA CEASES AND LAPSE RATES BEGIN TO
WEAKEN.
WITH CAA REGIME...USED A BLEND OF BIAS-CORRECTED MAV/MET GUIDANCE
FOR MAX/MIN TEMPS...WHICH WERE ON THE COLDER SIDE TDA AND WARMER
SIDE TNGT. TEMPS THIS AFTN WILL STRUGGLE TO REACH THE FREEZING
MARK NORTH AND WEST OF THE CITIES. MIN TEMPS IN THE TEENS AND 20S
TNGT...EXCEPT SINGLE DIGITS ALONG THE RIDGES. WIND CHILLS MAY DROP
BELOW ZERO IN THE WRN POTOMAC HIGHLANDS...BUT CONFIDENCE NOT HIGH
ENOUGH ATTM TO ISSUE A SECOND PERIOD WIND CHILL ADVISORY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AN ACTIVE PATTERN TO SAY THE LEAST...AS WE GO INTO AN ALMOST
EVERY-OTHER-DAY WX SYSTEM FOR THE COMING WEEK - IF NOT LONGER.
MONDAY WILL BE THE REPRIEVE FROM THIS WEEKEND`S SYSTEM. PART OF THE
ERN SECTION OF THE CWA WILL STILL BE ON THE TAIL-END OF THE EXITING
SYSTEM...KEEPING TEMPS A FEW DEGREES LOWER MON AFTN THAN THE
SHENANDOAH VLY. ALL AREAS WILL APPROACH 40 DEG BY MID AFTN...THOUGH
WEAK DOWNSLOPING ACROSS THE WRN MTNS/VLYS WILL HELP WARM TEMPS UP A
FEW MORE DEGREES...POSSIBLY REACHING THE M-U40S IN PLACES ALONG AND
E OF I-81.
SKIES WILL CLEAR OUT OTHER THAN SOME PASSING CIRRUS/MID LEVEL
STRATUS - THE TAIL END OF A WARM FRONT THAT WILL PASS WELL TO OUR
NORTH. THE FRONT WILL BE THE PRECURSOR TO THE NEXT SYSTEM THAT WILL
QUICKLY DEVELOP E OF THE MS RVR...REACH PEAK INTENSITY JUST TO OUR
WEST OVER THE OHIO RVR VLY AND DISSIPATE AS IT MOVES ACROSS THE ERN
SEABOARD.
DESPITE LOSING MUCH OF ITS MOISTURE OVER THE UPPER MIDWEST BEFORE
EVEN CROSSING THE MTNS...WHAT PRECIP DOES MOVE ACROSS THE AREA WILL
START OFF AS A WINTRY MIX ACROSS MUCH OF THE AREA TO START THE DAY
ON TUE. ENOUGH LOW LEVEL SUBFREEZING AIR WILL BE IN PLACE NEAR THE
SFC...WHILE A WARM NOSE ALOFT IN THE BOUNDARY LAYER (FROM A STRONG
LOW LEVEL JET MAX) WILL BE AT LEAST A COUPLE/FEW DEGREES ABOVE
FREEZING. THE NAM DEPICTS A GOOD COMPACT LOW LEVEL JET MAX...W/ THE
GFS SHOWING MORE OF A BROAD COLUMN OF STRONGER WINDS...WHICH IS
LIKELY A BIT TOO STRONG.
A MIX OF RAIN/SLEET/FREEZING RAIN POSSIBLE FROM ONSET - PREDAWN HRS
THRU MID-LATE MRNG. MORE OF A SNOW/WINTRY MIX FOR THE WRN ZONES AND
HIGHER TERRAIN. PRECIP WILL BECOME ALL-RAIN OUTSIDE THE MTNS FOR THE
EARLY-MID AFTN HRS...STILL ONLY LIGHT QPF...UNTIL THE INCOMING COLD
FRONT MOVES THIS ACTIVITY EAST OF THE AREA BY LATE AFTN/EARLY EVE.
MOST GUIDANCE MEMBERS IN GOOD AGREEMENT ON TIMING/QPF ASSOCIATED W/
SYSTEM BUT WENT W/ MORE OF A MET BLEND - SLIGHTLY LOWER TEMPS - AND
MORE CLOUD COVER LINGERING INTO THE LATE AFTN BEHIND THE FRONTAL
PASSAGE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WE`LL HAVE A COUPLE OF DAYS BEFORE THE NEXT SYSTEM ARRIVES - WED
AND THU. THE DEEP PARENT UPPER LOW RESPONSIBLE FOR THE TUE SYSTEM
WILL SWING BY TO OUR NORTH ON WED...KEEPING TEMPS BELOW AVG EACH
DAY. EVEN ON THU...THE BEFORE FRONTAL HIGH PRESSURE RIDGE WON`T BE
ABLE TO BUILD IN STRONG ENOUGH TO BRING MORE MILD TEMPS TO THE
AREA. EACH DAY WILL HOWEVER BE DRY AND MOSTLY CLEAR...THOUGH THE
NEXT LOW PRESSURE SYSTEM WILL BE ON THE DOORSTEP THU NIGHT.
GFS/EURO IS GOOD AGREEMENT THIS FAR OUT THAT THE NEXT LOW PRESSURE
SYSTEM WILL DEVELOP OVER THE CNTRL PLAINS MID WEEK...W/ THE SYSTEM
BASICALLY SPLITTING IN HALF AS IT MOVES EWD. THE SRN BRANCH WILL
THEN BE PICKED UP AND MOVE TOWARD THE AREA INTO THE COMING
WEEKEND...W/ ANOTHER POSSIBLE WINTRY MIX FRI AND SAT.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
PREDOMINANTLY VFR CONDITIONS TDA. MAIN WX CONCERN WILL BE THE GUSTY
NW WINDS AND SHSN. COVERAGE OF SHSN WILL BE LOW TDA...SO UNCERTAINTY
IN TIMING OF THIS ACTIVITY AT A SPECIFIC TERMINAL IS VERY HIGH.
THERE IS A POTENTIAL FOR SOME OF THESE SHSN TO BRIEFLY PRODUCE LOW
VSBYS AND GUSTY WINDS /25-30 KT THIS MRNG AND 30-40 KT THIS AFTN/.
MORE DETAIL WE NEED TO BE ADDED TO SUBSEQUENT TAFS AS WE MONITOR
THIS ACTIVITY ON RADAR.
VFR CONDITIONS TNGT. BREEZY NW WINDS CONTINUE THIS EVE WITH GUSTS TO
35 KT POSSIBLE. WINDS WEAKEN OVNGT.
HIGH PRESSURE MONDAY...WEST WINDS 10-15KT AND MOSTLY CLEAR SKIES.
A COLD FRONT WILL QUICKLY SLIDE OVER THE AREA TUE AFTN...BRINGING
SOME WINTRY MIX OUT AHEAD OF IT...CHANGING TO RAIN BY AFTN AND
MOVING OFF THE COAST TUE EVE. WED-THU MORE HIGH PRESSURE...THEN AN
ACTIVE END TO THE WEEK AS A FRONTAL BOUNDARY SIMILAR TO TUESDAY`S
PASSAGE BRINGS MORE WINTRY PRECIP ON FRI.
&&
.MARINE...
A GALE WRNG HAS BEEN ISSUED FOR ALL MARINE ZONES TDA AND TNGT...WITH
GALES LIKELY OCCURRING DURING THE AFTN AND EVE /BUT MAY CONTINUE A
FEW HRS OVNGT IN THE CHSPK BAY/. ISO SNOW SHOWERS WILL PRODUCE
LOCALLY HIGHER GUSTS AND BRIEF REDUCTIONS IN VSBYS FROM MID MRNG
THRU ERY AFTN.
SCA CONDITIONS WILL REAPPEAR ON MON NIGHT...AFTER A RELATIVELY
QUIET DAY OF HIGH PRES. A WEAK COLD FRONT WILL MOVE THRU W/ LIGHT
PRECIP ON TUE...THOUGH WINDS WILL PICK UP AGAIN WELL INTO SCA
RANGE TUE INTO WED. HIGH PRESSURE FOR THE BACK HALF OF THE
WEEK...AHEAD OF ANOTHER LOW PRESSURE SYSTEM FOR THE END OF THE WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MDZ501.
VA...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
WVZ501-503-505.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
ANZ530>543.
GALE WARNING UNTIL 6 AM EST MONDAY FOR ANZ530>543.
&&
$$
KLEIN/GMS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1205 AM EST SUN FEB 17 2013
.AVIATION...
//DISCUSSION...
DRIER IS WORKING IN FROM THE NORTHWEST EARLY THIS MORNING...WHICH
SHOULD ALLOW TAF SITES TO GO CLEAR-SCT FROM NORTH TO SOUTH OVER THE
NEXT SEVERAL HOURS. DIURNAL STRATO-CU (2500-3500) IS EXPECTED TO
DEVELOP BY LATE MORNING...PERSISTING FOR THE AFTERNOON HOURS.
SURFACE RIDGE IN PLACE FOR THE EARLY EVENING HOURS IS EXPECTED TO
YIELD CLEAR-SCT CLOUDS ONCE AGAIN...BUT A QUICK RAMP IN MID CLOUDS
WILL OCCUR TOWARD MONDAY MORNING.
FOR DTW...ONE LAST BATCH OF SNOW SHOWERS DROPPING SOUTH FROM OAKLAND
COUNTY MAY HOLD TOGETHER AND PRODUCE MVFR SNOW 6-8Z...WITH PARTIAL
CLEARING OCCURRING SHORTLY THEREAFTER.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FEET 06-08Z...LOW
CONFIDENCE 9-15Z...WITH MEDIUM CONFIDENCE 15-01Z.
* HIGH CONFIDENCE IN PRECIPITATION TYPE BEING SNOW.
&&
.PREV DISCUSSION...ISSUED 1044 PM EST SAT FEB 16 2013
UPDATE...
UPDATED TO UPGRADE SANILAC COUNTY TO LAKE EFFECT SNOW WARNING AS
SNOW SHOWERS INDEED CONSOLIDATED INTO AN INTENSE SNOW BAND AROUND
THE PERIPHERY OF NOW WELL DEVELOPED MESO VORTICITY OVER THE
SOUTHERN EDGE OF THE LAKE. CONVECTIVE TOPS CONTINUE TO RUN AT
10KFT WITH 30-35 DBZ RETURNS COMMON ON EXETER WSO RADAR (PUSHING
30 DBZ ON KDTX 88D @ AROUND 8KFT)...SO SUSPECT 2 TO 3 INCH PER
HOUR SNOWFALL RATES IN THE CORE OF THE LARGEST BAND. ORIENTATION
OF THIS BAND AND ANOTHER WEAKER ONE JUST TO ITS NORTH SUGGEST
PARTS OF THE COUNTY WILL RECEIVE 3 TO 4 HOURS WORTH OF AT LEAST 2
INCH PER HOUR SNOW...SO 8+ INCHES WILL BE QUITE POSSIBLE.
PREV DISCUSSION...ISSUED 731 PM EST SAT FEB 16 2013
UPDATE...
WILL MAINTAIN WINTER WEATHER ADVISORY FOR HURON...SANILAC AND ST
CLAIR COUNTIES AS SYNOPTIC SCALE SNOW TRANSITIONS TO SCATTERED TO
NUMEROUS LAKE EFFECT SNOW SHOWERS THIS EVENING AS SHORTWAVE PIVOTS
EAST INTO ONTARIO.
VISIBLE SATELLITE EARLIER DENOTED TWO MAIN MESO-VORTICITY CENTERS
ENHANCING INTENSE SNOW SHOWERS OVER LAKE HURON...ONE 50 KM NORTH
OF GODERICH ONTARIO AND THE OTHER PIVOT SOUTH ONTO THE TIP OF THE
THUMB. HIRES MODELS...3KM HRRR...LOCAL 4KM WRF AND 13KM RUC...HAD
DECENT HANDLE ON EASTERNMOST VORT CENTER...BUT ALL BUT MISSED THE
WESTERNMOST CENTER.
AS THE EVENING HAS PROGRESSED...THIS WESTERN VORTICITY CENTER HAS
TRACKED THROUGH THE THUMB AND BROUGHT ISOLATED INTENSE SNOW
SHOWERS. IT HAS ALSO SEEMED TO ACCELERATE THE SOUTHWARD PIVOT OF
THE OTHER CENTER...AS COMPARED TO THE HIRES MODEL SOLUTIONS WHICH
BROUGHT A GOOD DEAL OF CONVERGENCE ON SHORE...CENTERED ON SANILAC
COUNTY. AS LONG AS THIS TREND CONTINUES (AND THE MOST RECENT 21Z
HRRR RUN SHIFTED THIS DIRECTION)...THE MOST INTENSE AND PERSISTENT
SNOW SQUALLS WILL REMAIN MAINLY OFFSHORE. STILL EXPECT 3 TO 6
INCHES OF SNOW IN LOCAL AREAS NEAR THE LAKE HURON SHORELINE AS
THIS AREA OF SNOW SHOWERS PIVOTS SOUTH AND BRUSHES THE REGION.
IF SECOND MESO VORT IS ABLE TO WOBBLE WESTWARD AT ALL LATER THIS
EVNEING AS IT WORKS IN BEHIND THE FIRST CENTER...A LAKE EFFECT SNOW
WARNING WOULD BE REQUIRED AS ECHO TOPS ON KAPX/KDTX 88DS HAVE BEEN
RUNNING AT 10+ KFT WITH EXETER WSO RADAR SHOWING 30-35 DBZ CORES
IN SIMILAR INTENSE SNOW SHOWERS. THESE TOGETHER SUPPORT 2 TO 3
INCH PER HOUR SNOWFALL RATES IN THE MOST INTENSE SQUALLS SO ANY
BANDING SETTING UP ONSHORE FOR 2 TO 3 HOURS WOULD BRING TOTALS IN
EXCESS OF 6 INCHES.
PREV DISCUSSION...ISSUED 352 PM EST SAT FEB 16 2013
SHORT TERM...THIS AFTERNOON AND TONIGHT
UPPER LEVEL WAVE AND MID LEVEL COLD POOL HAVE BROUGHT SEVERAL SNOW
SQUALLS TO SOUTHEAST MICHIGAN TODAY...DROPPING A QUICK 1 TO 2 INCHES
OF SNOW ACROSS AREAS ALONG AND SOUTH OF THE INTERSTATE 69 CORRIDOR.
HOWEVER THE SURFACE TROUGH AND PV ANOMALY HAVE YET TO TRACK THROUGH
SOUTHEAST MICHIGAN. THESE FEATURES WILL TRACK THROUGH DURING THE
EVENING HOURS AND TURN WINDS TO A NORTHERLY DIRECTION...BRINGING
COOLER AIR AND LAKE MOISTURE IN FROM LAKE HURON. ALTHOUGH THE DTX
HIRES WRF RUNS DEVELOP AN IMPRESSIVE LAKE EFFECT BAND THAT TRACKS
THROUGH THE THUMB REGION BETWEEN 21Z AND 06Z...MODEL INITIALIZATION
IS VERY POOR AS THE 20Z PANEL INDICATES THERE SHOULD BE AN
IMPRESSIVE BAND JUST OFFSHORE OF HURON COUNTY...WHICH BY THE VISIBLE
SATELLITE IMAGERY IS FAR FROM REALITY. THIS FAILURE IN THE MODEL
LOOKS TO BE THE FAILURE OF A MESOLOW TO DEVELOP ACROSS CENTRAL LAKE
HURON...INSTEAD THE LAKE EFFECT IS IN A NORTHWEST TO SOUTHEAST
ORIENTATION BEHIND THE MAIN SURFACE TROUGH. THIS IS ACTUALLY
DEPICTED RATHER WELL BY THE HRRR MODEL WHICH BRINGS THIS FEATURE
SOUTH THROUGH THE EARLY EVENING HOURS AND DEVELOPS A NORTH-SOUTH
BAND OF LAKE EFFECT SNOW ACROSS THE EASTERN THUMB WITH SIGNIFICANT
ASSISTANCE FROM CONVERGENCE AS NORTH-NORTHWEST WINDS OVER THE LAKE
CONVERGE WITH NORTHEASTERLY WINDS ACROSS SOUTHERN LAKE HURON. THIS
SETUP WOULD BRING SEVERAL INCHES OF ACCUMULATING SNOW TO SANILAC AND
ST. CLAIR COUNTIES DURING THE EVENING HOURS UNTIL LAKE WINDS TURN
MORE NORTHERLY AND CONVERGENCE ALONG THE LAKE BECOMES BROADER. TO
ADD TO THE CONFUSION THE NAM MODEL IS VERY BRIEF WITH THE
CONVERGENCE AND KEEPS MOST OF THE LAKE EFFECT SNOW OFFSHORE DURING
THE EVENING HOURS.
GIVEN THE GOOD INITIALIZATION INCLINATION IS TO LEAN TOWARDS THE
HRRR SOLUTION AS EAST-WEST BANDS TEND TO TRANSITION TO NORTH-SOUTH
AS THEY ENCOUNTER THE TOPOGRAPHY OF THE THUMB REGION...HOWEVER
CANNOT RULE OUT THE POSSIBILITY OF A MESOLOW FORMING AND TRACKING
FARTHER INLAND THAN SANILAC AND ST. CLAIR COUNTIES. THEREFORE WILL
HANG ONTO THE WINTER WEATHER ADVISORY FOR THE THUMB REGION AND LET
LATER SHIFTS PARE DOWN THE HEADLINE AS THE NATURE AND ORIENTATION OF
THE LAKE EFFECT BECOME APPARENT DURING THE EVENING HOURS. THE
PREVIOUS FORECAST AMOUNTS STILL LOOK SOLID IN THIS REGION WITH A
GOOD 2 TO 4 INCHES EXPECTED WITH ISOLATED 6 INCH AMOUNTS NEAR THE
LAKE HURON SHORELINE AREAS.
LONG TERM...SUNDAY THROUGH FRIDAY
VERY STRONG NEGATIVE POTENTIAL VORTICITY ADVECTION FROM RETREATING
LARGE WAVELENGTH UPPER LEVEL TROUGH WILL LEAD TO RAPID 1000-500MB
GEOPOTENTIAL HIGH RISES OVER SOUTHEASTERN MICHIGAN 12-00Z SUNDAY.
THE MAXIMUM OF GEOPOTENTIAL HEIGHT RISES WILL REMAIN OVER THE
SOUTHERN APPALACHIANS IN RESPONSE TO THE BOMBING
NOR`EASTER...HOWEVER...HEIGHT RISE RIDGE AXIS WILL EXTEND NORTHWARD
INTO CENTRAL GREAT LAKES. REMNANT LAKE EFFECT WILL BE ONGOING OVER
SOUTH LAKE HURON THROUGH SUNDAY AFTERNOON BEFORE SWEEPING EASTWARD
DUE TO INCREASING WESTERLY COLUMN FLOW. HIGH TEMPERATURES TOMORROW
WILL BE CONSIDERABLY COLD...SOME 10-13 DEGREES BELOW NORMAL. A
RATHER RAW DAY WITH JUST ENOUGH WIND MAGNITUDE TO ALLOW FOR WIND
CHILL VALUES IN THE SINGLE DIGITS BEFORE NOON...TOPPING OUT BETWEEN
10-15 DEGREES FOR THE AFTERNOON. TYPICAL QUESTION MARK EXISTS
CONCERNING POTENTIAL FOR STRATOCUMULUS TOMORROW. THE AREAS
POSITION/PROXIMITY WITHIN EDGE OF RETREATING TROUGH AND OVERALL
ARCTIC AIRMASS SUGGESTS SUNSHINE WILL GREET US IN THE MORNING. THIS
CERTAINLY HAS SUPPORT WHEN LOOKING AT SATELLITE IMAGERY OVER
NORTHERN MINNESOTA. THE MODELED INVERSION AT ROUGHLY 5 KFT AGL IS
INTERESTING AS THE SOLUTION SHOWS NO MOISTURE TRAPPED WITHIN THE
STABLE STRATIFIED LAYER IMMEDIATELY ABOVE INVERSION BASE OR EVEN AT
THE INVERSION BASE ITSELF. WILL CONTINUE WITH THE INHERITED FORECAST
WHICH CALLS FOR SUNSHINE TOMORROW.
MODELS ARE COMING INTO AN AGREEMENT WITH THE SYSTEM THAT WILL
APPROACH THE AREA MONDAY NIGHT. OVERALL...SYSTEM DYNAMICAL SUPPORT
APPEARS ABOVE AVERAGE AS THE SOUTHERN EXTENSION OF THE MIDLEVEL
TROUGH WILL BECOME LINKED TO SOUTHERN STREAM JET STREAM ENERGY OVER
THE FOUR CORNERS AREA SUNDAY NIGHT. THE TROUGH AXIS WHICH WILL BEGIN
AT A POSITIVE TILT WILL TURN NEUTRAL MONDAY NIGHT AND EVENTUALLY
NEGATIVE BY TUESDAY MORNING. THE PRECEDING WARM AIR ADVECTION...WING
OF ISENTROPIC LIFT IS SHOWN TO BE DRY. IT WILL REQUIRE ACTUAL
MOISTURE TRANSPORT AND UPPER LEVEL JET SUPPORT TO GET PRECIPITATION
GOING. DELAYED PRECIPITATION ONSET TIMING A FEW HOURS...NOW EXPECTED
MAINLY FOR THE FIRST HALF OF MONDAY NIGHT. THE GFS SOLUTION AND
RESULTANT PRECIPITATION TYPE SEEMS HIGHLY SUSPECT GIVEN THE OVERALL
HEIGHT PATTERN AND FORECASTED WIND FIELD. REST OF THE MEDIUM RANGE
SUITE SUGGESTS THAT A SUBSTANTIAL WARM LAYER FROM SFC-5 KFT AGL WILL
SLIDE IN SUPPORTING A RAPID TRANSITION TO RAIN. FROM THIS VANTAGE
POINT THIS SYSTEM HAS THE POTENTIAL TO BECOME A HIGHER IMPACT WIND
EVENT. RIGHT NOW...FORECASTED VALUES OF UPWARDS OF 30 KNOTS SEEMS
GOOD...WITH ALL THE MAIN FEATURE SLIGHTLY OUT OF PHASE. SUBSEQUENT
SHIFTS CAN FINE TUNE THIS.
MARINE...
OTHER THAN AN ACTIVE SNOW SHOWER PATTERN TONIGHT...MARINE CONDITIONS
WILL BE FAVORABLE THROUGH SUNDAY IN TERMS OF WIND OVER ALL MARINE
AREAS AND WAVES OVER THE OPEN WATERS OF LAKE HURON. AFTER THAT...A
STRONG LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE PLAINS
AND MIDWEST AND MOVE THROUGH THE GREAT LAKES MONDAY AND TUESDAY.
MILD AIR SPREADING NORTHWARD AHEAD OF THE SYSTEM WILL BRING RAIN TO
ALL AREAS EXCEPT THE FAR NORTH REACHES OF LAKE HURON. A STRONG COLD
FRONT IS EXPECTED TO BRING A SHARP WESTERLY WIND SHIFT TUESDAY
MORNING BUT SPEEDS ARE EXPECTED TO REMAIN BELOW GALE FORCE FOR
NOW. STRONG NORTHWEST WIND TRAILING THE FRONT WILL EASE IN SPEED
DURING WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING...MIZ055...UNTIL 2 AM SUNDAY.
WINTER WEATHER ADVISORY...MIZ063...UNTIL 2 AM SUNDAY.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SF
UPDATE.......DG
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EST SUN FEB 17 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BUILD TOWARD THE CAROLINAS FROM THE
SOUTHWEST TODAY AS A RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM
OFFSHORE THE MID ATLANTIC COAST TRACKS NORTHEAST TOWARD THE CANADIAN
MARITIMES. HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT BEFORE
MOVING OFFSHORE LATE MONDAY INTO MONDAY NIGHT AS A COLD FRONT
APPROACHES THE MOUNTAINS FROM THE WEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM SUNDAY...
THIS MORNING:
A LINGERING NNW-SSE ORIENTED BAND OF SNOW OVER THE COASTAL PLAIN
WILL CONTINUE TO WEAKEN...DISSIPATING BY 300-330 AM AS THE UPPER
LEVEL TROUGH AXIS PROGRESSES EAST OF CENTRAL NC AND STRENGTHENING
SYNOPTIC SUBSIDENCE RESULTS IN RAPID DRYING ALOFT. AS MUCH AS 1.0 TO
1.5 INCHES OF SNOW ACCUMULATION OCCURRED IN ASSOCIATION WITH THIS
BAND OVER GRANVILLE...VANCE...FRANKLIN...EASTERN WAKE... JOHNSTON...
WAYNE AND EASTERN SAMPSON COUNTIES BETWEEN 900 PM SATURDAY EVENING
AND 200 AM THIS MORNING. EXPECT DANGEROUS ROAD CONDITIONS ALONG THE
INTERSTATE 85 CORRIDOR FROM DURHAM NORTH TO THE VIRGINIA
BORDER...ALONG THE INTERSTATE 40 CORRIDOR FROM RALEIGH EAST TO
BENSON-HOBBTON-WARSAW...AND ALONG THE INTERSTATE 95 CORRIDOR FROM
BENSON NORTH TO ROANOKE RAPIDS. HAVE HIGHLIGHTED THESE AREAS IN THE
WINTER WEATHER ADVISORY THAT REMAINS IN EFFECT UNTIL 10 AM THIS
MORNING...WHEN TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING.
ADDITIONAL SHORTWAVE ENERGY APPROACHING WEST VIRGINIA AT 07Z IS
PROGGED TO TRACK SOUTHEAST THROUGH SOUTHERN VA AND NORTHEAST NC
BETWEEN 12-15Z THIS MORNING...IN THE PRESENCE OF LINGERING LOW-LEVEL
MOISTURE AND STEEP MID-LEVEL LAPSE RATES (7-7.5 C/KM) OVER THE N/NE
OF THE TRIANGLE INTO CENTRAL/SOUTHEAST VA (PER 00Z RAOB AND THE
LATEST RAP MODEL DATA). IT IS POSSIBLE THAT FLURRIES MAY OCCUR N AND
NE OF THE TRIANGLE TOWARD THE VA BORDER (ROXBORO EAST TO ROANOKE
RAPIDS) BETWEEN 09-15Z WHERE DPVA IN THE PRESENCE OF STEEP MID-LEVEL
LAPSE RATES AND LINGERING LOW-LEVEL MOISTURE IN THE ICE NUCLEATION
ZONE MAY (BARELY) OVERCOME STRENGTHENING SUBSIDENCE ALOFT...THOUGH
NO MEASURABLE PRECIPITATION WOULD BE EXPECTED. 07Z RADAR DATA FROM
KFCX LENDS CREDENCE TO THIS POSSIBILITY.
THIS AFTERNOON THROUGH TONIGHT:
PRONOUNCED DRYING ALOFT (ESPECIALLY 8+ KFT AGL) WILL OCCUR
THROUGHOUT THE DAY AS THE UPPER LEVEL TROUGH AXIS PROGRESSES
OFFSHORE THE MID-ATLANTIC AND CAROLINA COAST. LOW-LEVEL MOISTURE
PROGGED TO ADVECT INTO THE REGION FROM THE NW UNDERNEATH THE
STRENGTHENING MID-LEVEL SUBSIDENCE INVERSION MAY ALLOW FOR SCATTERED
CLOUD COVER WITH BASES AT 5-7 KFT AGL TODAY. OTHERWISE...EXPECT
MOSTLY SUNNY SKIES. 1000-850 MB THICKNESSES AND H85 TEMPS SUGGEST
CHILLY TEMPS TODAY...RANGING FROM THE MID 30S N/NE TO UPPER 30S AND
LOWER 40S FAR S/SW. 25-35 KT FLOW NW FLOW IN THE MIXED LAYER
(STRONGEST THROUGH 18Z) WILL RESULT IN BREEZY CONDITIONS...
ESPECIALLY N/NE OF THE TRIANGLE. EXPECT SUSTAINED NW WINDS AT 10-20
MPH WITH GUSTS GENERALLY IN THE 20-30 MPH RANGE...THOUGH SPORADIC
HIGHER GUSTS UP TO 35 MPH WILL BE POSSIBLE. EXPECT WIND CHILL VALUES
IN THE TEENS (PRIMARILY NORTH OF HWY 64) THIS MORNING...AND
LINGERING IN THE 20S THIS AFTERNOON...ESPECIALLY IN THE NORTH. WITH
A COLD/DRY AIRMASS IN PLACE...CLEAR SKIES AND AND CALM WINDS TONIGHT
AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST... EXPECT EXCELLENT RADIATIONAL COOLING WITH CHILLY LOWS
RANGING FROM THE MID/UPPER TEENS IN RURAL/LOW-LYING AREAS TO LOWER
20S IN URBAN AREAS. -VINCENT
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
AS THE COLD MODIFIED ARCTIC SURFACE HIGH SLIPS EAST AND OFFSHORE
MONDAY... THE RETURN FLOW WILL BRING A STRONG WARMING TREND BY
AFTERNOON. HOWEVER... THE AIR MASS WILL REMAIN DRY AND WITH THE
BREEZY WINDS (EVEN IF THEY ARE FROM THE SW) IT WILL STILL FEEL
RATHER CHILLY. HIGHS 50-55 EXPECTED WITH MOSTLY SUNNY SKIES.
INCREASING MID AND HIGH LEVEL MOISTURE WILL LEAD TO PARTLY CLOUDY
BECOMING MOSTLY CLOUDY SKIES MONDAY NIGHT. LOWS WILL BE MUCH MILDER
WITH LOWS IN THE UPPER 30S TO MID 40S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 317 AM SUNDAY...
THE MAIN STORM TRACK WITH THE NEXT APPROACHING SYSTEM IS EXPECTED TO
BE FROM THE MIDWEST NE ACROSS THE GREAT LAKES TUE-TUE NIGHT. THE
TRAILING COLD FRONT IS EXPECTED TO PUSH EAST ACROSS OUR REGION
TUESDAY. INITIALLY... A STRONG AND MOIST FLOW FROM THE GULF WILL
ALLOW FOR SIGNIFICANT RAIN INTO THE TENNESSEE VALLEY INTO FAR
WESTERN NC INTO MONDAY NIGHT. HOWEVER... AS THE STORM MOVES OVER THE
GREAT LAKES... THE MEAN FLOW IS EXPECTED TO BECOME PROGRESSIVELY
MORE WESTERLY AS THE SYSTEM MOVES ACROSS THE APPALACHIANS TO THE
MID-ATLANTIC COAST TUESDAY AFTERNOON AND EVENING. THIS EFFECTIVELY
SHUTS DOWN THE GULF INFLOW AS THE COLD FRONT MOVES THROUGH CENTRAL
NC. WE WILL CONTINUE TO CARRY HIGH POPS BUT LOW QPF. MOST AREAS
SHOULD SEE LESS THAN 0.25 WITH EASTERN ZONES POSSIBLY LESS THAN
0.10. THE LIKELY POP WILL BE CONFINED TO TUESDAY... WITH RAPIDLY
DECREASING POP TUESDAY EVENING FROM WEST TO EAST AS THE COLD FRONT
REACHES THE COAST. HIGHS TUESDAY WILL BE HELD DOWN DUE TO THE CLOUDS
AND SHOWERS. EXPECT SOME 40S TO HOLD ON OVER THE PIEDMONT... WITH
50S SE. SKIES WILL BECOME PARTLY CLOUDY TUESDAY NIGHT WITH CAA
LEADING TO LOWS OF 30-35.
WED-THU... VERY COLD AND STRONG ARCTIC HIGH PRESSURE WILL AFFECT THE
UPPER MIDWEST AND GREAT LAKES. THIS HIGH PRESSURE IS FORECAST TO
BUILD SOUTH INTO NC THIS PERIOD. HOWEVER... THE CORE OF THE ARCTIC
AIR IS FORECAST TO REMAIN FROM AROUND NORTHERN VA NORTHWARD. YET...
THE FEED OF DRY AND COLD AIR WILL ALLOW TEMPS TO FALL BELOW NORMAL
WED NIGHT AND THURSDAY. MOSTLY CLEAR SKIES ARE EXPECTED WED-THU...
HIGHS WED SHOULD BE IN THE UPPER 40S TO MID 50S... COOLING INTO THE
MID 40S TO LOWER 50S THURSDAY. LOWS WED SHOULD BE 25-30.
BY FRIDAY... ANOTHER STORM SYSTEM IS EXPECTED TO FOLLOW THE SAME
GENERAL TRACK AS THE LAST SEVERAL STORMS... FROM THE PLAINS TO THE
GREAT LAKES. HOWEVER... THE LARGE COLD SURFACE HIGH SHOULD BE
LOCATED OVER NEW ENGLAND THU NIGHT... THEN SLOWLY DRIFT EAST BY
FRIDAY AND FRIDAY NIGHT. THE HIGH IS FORECAST TO BE MORE THAN STRONG
ENOUGH... AND IN MORE THAN ADEQUATE POSITION TO FAVOR A CLASSICAL TO
HYBRID CAD EVENT FOR FRI-FRI NIGHT AS THE PRECIPITATION ASSOCIATED
WITH THE STORM SYSTEM ARRIVES FROM THE WEST. FOR NOW... IT DOES
APPEAR TO BE WARM ENOUGH FOR RAIN... ALTHOUGH THIS WILL HAVE TO BE
WATCHED CLOSELY FOR FRIDAY. LOWS 30-35. HIGHS 38-48 NW TO SE.
THE FRONT SHOULD SETTLE SOUTH OF THE REGION OVER THE WEEKEND... WITH
ANOTHER POTENTIAL STORM WITH SIGNIFICANT PRECIPITATION OVER THE SE
INTO THE MID-ATLANTIC LATER IN THE WEEKEND. THE POTENTIAL STORM
TRACK FROM THE GULF TO THE SE STATES ALLOWS POTENTIAL FOR WINTERY
PRECIP INTO THE MID-ATLANTIC STATES... BUT THE QUESTION WILL BE THE
POSITION AND STRENGTH OF THE SURFACE HIGH THAT WILL FOLLOW THE
FRONT FRIDAY... AND HOW FAR SOUTH THE COLD AIR CAN REACH.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD AS AN INTENSIFYING
LOW PRESSURE SYSTEM TRACKS FURTHER OFFSHORE INTO THE ATLANTIC. THE
PRIMARY AVIATION CONCERN WILL BE BREEZY WNW/NW WINDS TODAY...
SUSTAINED AT 15 KT WITH GUSTS GENERALLY TO 25 KT...THOUGH A PERIOD
OF STRONGER WINDS SUSTAINED AT 20 KT WITH GUSTS UP TO 30 KT WILL BE
POSSIBLE...PRIMARILY BETWEEN 12-18Z...ESPECIALLY AT THE RWI
TERMINAL. WINDS WILL DECREASE TO 5-10 KT AFTER 21Z...BECOMING LIGHT
AND VARIABLE AFTER 00Z.
LOOKING AHEAD:
VFR CONDITIONS WILL RULE THROUGH MONDAY IN ASSOCIATION WITH DRY HIGH
PRESSURE. HIGH PRESSURE WILL MOVE OFFSHORE MONDAY NIGHT AS A COLD
FRONT APPROACHES THE MOUNTAINS FROM THE WEST. EXPECT DETERIORATING
CONDITIONS WITH MVFR/IFR CEILINGS DEVELOPING IN ASSOC/W AN
INCREASINGLY MOIST RETURN FLOW BETWEEN 06-12Z TUE AND INCREASING
CHANCES FOR RAIN FROM WEST-EAST BETWEEN 12-18Z TUE. A PERIOD OF
SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL BE POSSIBLE BETWEEN 06Z TUE
MORNING AND 18Z TUE AFTERNOON AS A 40-45 KT LLJ DEVELOPS AS LOW DOWN
AS 1500-2000 FT AGL. EXPECT RAPID CLEARING AND A RETURN TO VFR
CONDITIONS IN THE WAKE OF THE COLD FRONTAL PASSAGE LATE TUE INTO TUE
NIGHT. VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY AS DRY HIGH
PRESSURE BUILDS OVER THE CAROLINAS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
258 AM EST SUN FEB 17 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BUILD TOWARD THE CAROLINAS FROM THE
SOUTHWEST TODAY AS A RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM
OFFSHORE THE MID ATLANTIC COAST TRACKS NORTHEAST TOWARD THE CANADIAN
MARITIMES. HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT BEFORE
MOVING OFFSHORE LATE MONDAY INTO MONDAY NIGHT AS A COLD FRONT
APPROACHES THE MOUNTAINS FROM THE WEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM SUNDAY...
THIS MORNING:
A LINGERING NNW-SSE ORIENTED BAND OF SNOW OVER THE COASTAL PLAIN
WILL CONTINUE TO WEAKEN...DISSIPATING BY 300-330 AM AS THE UPPER
LEVEL TROUGH AXIS PROGRESSES EAST OF CENTRAL NC AND STRENGTHENING
SYNOPTIC SUBSIDENCE RESULTS IN RAPID DRYING ALOFT. AS MUCH AS 1.0 TO
1.5 INCHES OF SNOW ACCUMULATION OCCURRED IN ASSOCIATION WITH THIS
BAND OVER GRANVILLE...VANCE...FRANKLIN...EASTERN WAKE... JOHNSTON...
WAYNE AND EASTERN SAMPSON COUNTIES BETWEEN 900 PM SATURDAY EVENING
AND 200 AM THIS MORNING. EXPECT DANGEROUS ROAD CONDITIONS ALONG THE
INTERSTATE 85 CORRIDOR FROM DURHAM NORTH TO THE VIRGINIA
BORDER...ALONG THE INTERSTATE 40 CORRIDOR FROM RALEIGH EAST TO
BENSON-HOBBTON-WARSAW...AND ALONG THE INTERSTATE 95 CORRIDOR FROM
BENSON NORTH TO ROANOKE RAPIDS. HAVE HIGHLIGHTED THESE AREAS IN THE
WINTER WEATHER ADVISORY THAT REMAINS IN EFFECT UNTIL 10 AM THIS
MORNING...WHEN TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING.
ADDITIONAL SHORTWAVE ENERGY APPROACHING WEST VIRGINIA AT 07Z IS
PROGGED TO TRACK SOUTHEAST THROUGH SOUTHERN VA AND NORTHEAST NC
BETWEEN 12-15Z THIS MORNING...IN THE PRESENCE OF LINGERING LOW-LEVEL
MOISTURE AND STEEP MID-LEVEL LAPSE RATES (7-7.5 C/KM) OVER THE N/NE
OF THE TRIANGLE INTO CENTRAL/SOUTHEAST VA (PER 00Z RAOB AND THE
LATEST RAP MODEL DATA). IT IS POSSIBLE THAT FLURRIES MAY OCCUR N AND
NE OF THE TRIANGLE TOWARD THE VA BORDER (ROXBORO EAST TO ROANOKE
RAPIDS) BETWEEN 09-15Z WHERE DPVA IN THE PRESENCE OF STEEP MID-LEVEL
LAPSE RATES AND LINGERING LOW-LEVEL MOISTURE IN THE ICE NUCLEATION
ZONE MAY (BARELY) OVERCOME STRENGTHENING SUBSIDENCE ALOFT...THOUGH
NO MEASURABLE PRECIPITATION WOULD BE EXPECTED. 07Z RADAR DATA FROM
KFCX LENDS CREDENCE TO THIS POSSIBILITY.
THIS AFTERNOON THROUGH TONIGHT:
PRONOUNCED DRYING ALOFT (ESPECIALLY 8+ KFT AGL) WILL OCCUR
THROUGHOUT THE DAY AS THE UPPER LEVEL TROUGH AXIS PROGRESSES
OFFSHORE THE MID-ATLANTIC AND CAROLINA COAST. LOW-LEVEL MOISTURE
PROGGED TO ADVECT INTO THE REGION FROM THE NW UNDERNEATH THE
STRENGTHENING MID-LEVEL SUBSIDENCE INVERSION MAY ALLOW FOR SCATTERED
CLOUD COVER WITH BASES AT 5-7 KFT AGL TODAY. OTHERWISE...EXPECT
MOSTLY SUNNY SKIES. 1000-850 MB THICKNESSES AND H85 TEMPS SUGGEST
CHILLY TEMPS TODAY...RANGING FROM THE MID 30S N/NE TO UPPER 30S AND
LOWER 40S FAR S/SW. 25-35 KT FLOW NW FLOW IN THE MIXED LAYER
(STRONGEST THROUGH 18Z) WILL RESULT IN BREEZY CONDITIONS...
ESPECIALLY N/NE OF THE TRIANGLE. EXPECT SUSTAINED NW WINDS AT 10-20
MPH WITH GUSTS GENERALLY IN THE 20-30 MPH RANGE...THOUGH SPORADIC
HIGHER GUSTS UP TO 35 MPH WILL BE POSSIBLE. EXPECT WIND CHILL VALUES
IN THE TEENS (PRIMARILY NORTH OF HWY 64) THIS MORNING...AND
LINGERING IN THE 20S THIS AFTERNOON...ESPECIALLY IN THE NORTH. WITH
A COLD/DRY AIRMASS IN PLACE...CLEAR SKIES AND AND CALM WINDS TONIGHT
AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST... EXPECT EXCELLENT RADIATIONAL COOLING WITH CHILLY LOWS
RANGING FROM THE MID/UPPER TEENS IN RURAL/LOW-LYING AREAS TO LOWER
20S IN URBAN AREAS. -VINCENT
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 240 PM SATURDAY...
TEMPS WILL BEGIN TO MODERATE ON MONDAY AS SHORTWAVE RIDGING BUILDS
EAST AND THE HIGH SLIPS OFFSHORE RESULTING IN A RETURN TO SOUTHERLY
FLOW. HIGHS IN THE UPPER 40S TO LOW/MID 50S ARE EXPECTED ON
MONDAY...WITH OVERNIGHT LOWS GENERALLY IN THE LOW/MID 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 240 PM SATURDAY...
SOUTHERLY FLOW WILL INCREASE AHEAD OF AN APPROACHING FRONT ON
TUESDAY AND THIS WILL ALLOW TEMPS TO WARM EVEN MORE...WITH HIGHS
POSSIBLY APPROACHING 60 DEGREES ACROSS THE SOUTHEAST. HOWEVER...
FURTHER TO THE NORTH AND WEST...INCREASING CLOUDS/PRECIP CHANCES
EARLIER IN THE DAY SHOULD HOLD TEMPS IN THE LOW/MID 50S (MAYBE EVEN
SOME UPPER 40S). THE FRONT IS EXPECTED TO CROSS THE REGION THROUGH
TUESDAY EVENING AND BRING WITH IT A GOOD CHANCE OF SHOWERS. BEHIND
THE FRONT...THERE SHOULD BE ENOUGH CLEARING TUESDAY NIGHT WHERE
TEMPS WOULD DROP INTO THE LOW/MID 30S.
SURFACE HIGH PRESSURE AND SHORTWAVE RIDGING WILL THEN DOMINATE THE
WEATHER ACROSS CENTRAL NC THROUGH THURSDAY. THIS WILL RESULT IN FAIR
WEATHER CONDITIONS AND NEAR NORMAL TEMPS. THE NEXT SYSTEM LOOKS TO
APPROACH THE AREA LATE THURSDAY NIGHT INTO FRIDAY. ALSO...THERE
CONTINUES TO BE INDICATIONS OF A CAD EVENT SETTING UP ACROSS THE
REGION AND THIS WILL HAVE TO BE MONITORED FOR POTENTIAL P-TYPE
ISSUES (ESPECIALLY AT THE ONSET OF ANY PRECIP) AND COOLER THAN
EXPECTED TEMPS...ESPECIALLY ACROSS THE NORTHWEST. FOR NOW...WILL
SHOW RAIN CHANCES INCREASING FROM WEST TO EAST DURING THE DAY ON
FRIDAY...WITH HIGHS RANGING FROM THE 40S ACROSS THE NORTHWEST TO
UPPER 50S (MAYBE NEAR 60 DEGREES) ACROSS THE EXTREME SOUTHEAST.
THERE IS UNCERTAINTY WITH RESPECT TO HOW QUICKLY THIS SYSTEM WILL
PROGRESS ACROSS THE REGION...WITH THE ECMWF MAINTAINING PRECIP
CHANCES THROUGH SATURDAY AS THE FRONT STALLS NEAR THE REGION. FOR
NOW WILL SHOW PRECIP ENDING ON SATURDAY...BUT CLOUDY CONDITIONS
PERSISTING.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD AS AN INTENSIFYING
LOW PRESSURE SYSTEM TRACKS FURTHER OFFSHORE INTO THE ATLANTIC. THE
PRIMARY AVIATION CONCERN WILL BE BREEZY WNW/NW WINDS TODAY...
SUSTAINED AT 15 KT WITH GUSTS GENERALLY TO 25 KT...THOUGH A PERIOD
OF STRONGER WINDS SUSTAINED AT 20 KT WITH GUSTS UP TO 30 KT WILL BE
POSSIBLE...PRIMARILY BETWEEN 12-18Z...ESPECIALLY AT THE RWI
TERMINAL. WINDS WILL DECREASE TO 5-10 KT AFTER 21Z...BECOMING LIGHT
AND VARIABLE AFTER 00Z.
LOOKING AHEAD:
VFR CONDITIONS WILL RULE THROUGH MONDAY IN ASSOCIATION WITH DRY HIGH
PRESSURE. HIGH PRESSURE WILL MOVE OFFSHORE MONDAY NIGHT AS A COLD
FRONT APPROACHES THE MOUNTAINS FROM THE WEST. EXPECT DETERIORATING
CONDITIONS WITH MVFR/IFR CEILINGS DEVELOPING IN ASSOC/W AN
INCREASINGLY MOIST RETURN FLOW BETWEEN 06-12Z TUE AND INCREASING
CHANCES FOR RAIN FROM WEST-EAST BETWEEN 12-18Z TUE. A PERIOD OF
SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL BE POSSIBLE BETWEEN 06Z TUE
MORNING AND 18Z TUE AFTERNOON AS A 40-45 KT LLJ DEVELOPS AS LOW DOWN
AS 1500-2000 FT AGL. EXPECT RAPID CLEARING AND A RETURN TO VFR
CONDITIONS IN THE WAKE OF THE COLD FRONTAL PASSAGE LATE TUE INTO TUE
NIGHT. VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY AS DRY HIGH
PRESSURE BUILDS OVER THE CAROLINAS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
257 AM EST SUN FEB 17 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BUILD TOWARD THE CAROLINAS FROM THE
SOUTHWEST TODAY AS A RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM
OFFSHORE THE MID ATLANTIC COAST TRACKS NORTHEAST TOWARD THE CANADIAN
MARITIMES. HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT BEFORE
MOVING OFFSHORE LATE MONDAY INTO MONDAY NIGHT AS A COLD FRONT
APPROACHES THE MOUNTAINS FROM THE WEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM SUNDAY...
THIS MORNING:
A LINGERING NNW-SSE ORIENTED BAND OF SNOW OVER THE COASTAL PLAIN
WILL CONTINUE TO WEAKEN...DISSIPATING BY 300-330 AM AS THE UPPER
LEVEL TROUGH AXIS PROGRESSES EAST OF CENTRAL NC AND STRENGTHENING
SYNOPTIC SUBSIDENCE RESULTS IN RAPID DRYING ALOFT. AS MUCH AS 1.0 TO
1.5 INCHES OF SNOW ACCUMULATION OCCURRED IN ASSOCIATION WITH THIS
BAND OVER GRANVILLE...VANCE...FRANKLIN...EASTERN WAKE... JOHNSTON...
WAYNE AND EASTERN SAMPSON COUNTIES BETWEEN 900 PM SATURDAY EVENING
AND 200 AM THIS MORNING. EXPECT DANGEROUS ROAD CONDITIONS ALONG THE
INTERSTATE 85 CORRIDOR FROM DURHAM NORTH TO THE VIRGINIA
BORDER...ALONG THE INTERSTATE 40 CORRIDOR FROM RALEIGH EAST TO
BENSON-HOBBTON-WARSAW...AND ALONG THE INTERSTATE 95 CORRIDOR FROM
BENSON NORTH TO ROANOKE RAPIDS. HAVE HIGHLIGHTED THESE AREAS IN THE
WINTER WEATHER ADVISORY THAT REMAINS IN EFFECT UNTIL 10 AM THIS
MORNING...WHEN TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING.
ADDITIONAL SHORTWAVE ENERGY APPROACHING WEST VIRGINIA AT 07Z IS
PROGGED TO TRACK SOUTHEAST THROUGH SOUTHERN VA AND NORTHEAST NC
BETWEEN 12-15Z THIS MORNING...IN THE PRESENCE OF LINGERING LOW-LEVEL
MOISTURE AND STEEP MID-LEVEL LAPSE RATES (7-7.5 C/KM) OVER THE N/NE
OF THE TRIANGLE INTO CENTRAL/SOUTHEAST VA (PER 00Z RAOB AND THE
LATEST RAP MODEL DATA). IT IS POSSIBLE THAT FLURRIES MAY OCCUR N AND
NE OF THE TRIANGLE TOWARD THE VA BORDER (ROXBORO EAST TO ROANOKE
RAPIDS) BETWEEN 09-15Z WHERE DPVA IN THE PRESENCE OF STEEP MID-LEVEL
LAPSE RATES AND LINGERING LOW-LEVEL MOISTURE IN THE ICE NUCLEATION
ZONE MAY (BARELY) OVERCOME STRENGTHENING SUBSIDENCE ALOFT...THOUGH
NO MEASURABLE PRECIPITATION WOULD BE EXPECTED. 07Z RADAR DATA FROM
KFCX LENDS CREDENCE TO THIS POSSIBILITY.
THIS AFTERNOON THROUGH TONIGHT:
PRONOUNCED DRYING ALOFT (ESPECIALLY 8+ KFT AGL) WILL OCCUR
THROUGHOUT THE DAY AS THE UPPER LEVEL TROUGH AXIS PROGRESSES
OFFSHORE THE MID-ATLANTIC AND CAROLINA COAST. LOW-LEVEL MOISTURE
PROGGED TO ADVECT INTO THE REGION FROM THE NW UNDERNEATH THE
STRENGTHENING MID-LEVEL SUBSIDENCE INVERSION MAY ALLOW FOR SCATTERED
CLOUD COVER WITH BASES AT 5-7 KFT AGL TODAY. OTHERWISE...EXPECT
MOSTLY SUNNY SKIES. 1000-850 MB THICKNESSES AND H85 TEMPS SUGGEST
CHILLY TEMPS TODAY...RANGING FROM THE MID 30S N/NE TO UPPER 30S AND
LOWER 40S FAR S/SW. 25-35 KT FLOW NW FLOW IN THE MIXED LAYER
(STRONGEST THROUGH 18Z) WILL RESULT IN BREEZY CONDITIONS...
ESPECIALLY N/NE OF THE TRIANGLE. EXPECT SUSTAINED NW WINDS AT 10-20
MPH WITH GUSTS GENERALLY IN THE 20-30 MPH RANGE...THOUGH SPORADIC
HIGHER GUSTS UP TO 35 MPH WILL BE POSSIBLE. EXPECT WIND CHILL VALUES
IN THE TEENS (PRIMARILY NORTH OF HWY 64) THIS MORNING...AND
LINGERING IN THE 20S THIS AFTERNOON...ESPECIALLY IN THE NORTH. WITH
A COLD/DRY AIRMASS IN PLACE...CLEAR SKIES AND AND CALM WINDS TONIGHT
AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST... EXPECT EXCELLENT RADIATIONAL COOLING WITH CHILLY LOWS
RANGING FROM THE MID/UPPER TEENS IN RURAL/LOW-LYING AREAS TO LOWER
20S IN URBAN AREAS. -VINCENT
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 240 PM SATURDAY...
THE SHORT TERM PERIOD WILL START WITH A COLD UPPER TROUGH OVER THE
EASTERN US...WHILE AT THE SURFACE...HIGH PRESSURE WILL GRADUALLY
BUILD IN BEHIND THE DEPARTING LOW THAT WILL BE TRACKING UP THE EAST
COAST. HIGHS ON SUNDAY WILL BE RATHER CHILLY...WITH TEMPS ONLY
RISING INTO THE MID/UPPER 30S TO LOWER 40S. IN ADDITION...WINDS WILL
BE QUITE BREEZY AS THE PRESSURE GRADIENT REMAINS TIGHT OVER THE AREA
BETWEEN THE DEPARTING AND DEEPENING LOW AND THE HIGH BUILDING IN.
THE PRESSURE GRADIENT WILL RELAX SUNDAY NIGHT AS THE HIGH BUILDS
NEARLY OVERHEAD AND GOOD RADIATIONAL COOLING CONDITIONS WILL SET
UP...ALLOWING OVERNIGHT LOWS TO FALL INTO THE LOW TO MID 20S. TEMPS
WILL BEGIN TO MODERATE ON MONDAY AS SHORTWAVE RIDGING BUILDS EAST
AND THE HIGH SLIPS OFFSHORE RESULTING IN A RETURN TO SOUTHERLY FLOW.
HIGHS IN THE UPPER 40S TO LOW/MID 50S ARE EXPECTED ON MONDAY...WITH
OVERNIGHT LOWS GENERALLY IN THE LOW/MID 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 240 PM SATURDAY...
SOUTHERLY FLOW WILL INCREASE AHEAD OF AN APPROACHING FRONT ON
TUESDAY AND THIS WILL ALLOW TEMPS TO WARM EVEN MORE...WITH HIGHS
POSSIBLY APPROACHING 60 DEGREES ACROSS THE SOUTHEAST. HOWEVER...
FURTHER TO THE NORTH AND WEST...INCREASING CLOUDS/PRECIP CHANCES
EARLIER IN THE DAY SHOULD HOLD TEMPS IN THE LOW/MID 50S (MAYBE EVEN
SOME UPPER 40S). THE FRONT IS EXPECTED TO CROSS THE REGION THROUGH
TUESDAY EVENING AND BRING WITH IT A GOOD CHANCE OF SHOWERS. BEHIND
THE FRONT...THERE SHOULD BE ENOUGH CLEARING TUESDAY NIGHT WHERE
TEMPS WOULD DROP INTO THE LOW/MID 30S.
SURFACE HIGH PRESSURE AND SHORTWAVE RIDGING WILL THEN DOMINATE THE
WEATHER ACROSS CENTRAL NC THROUGH THURSDAY. THIS WILL RESULT IN FAIR
WEATHER CONDITIONS AND NEAR NORMAL TEMPS. THE NEXT SYSTEM LOOKS TO
APPROACH THE AREA LATE THURSDAY NIGHT INTO FRIDAY. ALSO...THERE
CONTINUES TO BE INDICATIONS OF A CAD EVENT SETTING UP ACROSS THE
REGION AND THIS WILL HAVE TO BE MONITORED FOR POTENTIAL P-TYPE
ISSUES (ESPECIALLY AT THE ONSET OF ANY PRECIP) AND COOLER THAN
EXPECTED TEMPS...ESPECIALLY ACROSS THE NORTHWEST. FOR NOW...WILL
SHOW RAIN CHANCES INCREASING FROM WEST TO EAST DURING THE DAY ON
FRIDAY...WITH HIGHS RANGING FROM THE 40S ACROSS THE NORTHWEST TO
UPPER 50S (MAYBE NEAR 60 DEGREES) ACROSS THE EXTREME SOUTHEAST.
THERE IS UNCERTAINTY WITH RESPECT TO HOW QUICKLY THIS SYSTEM WILL
PROGRESS ACROSS THE REGION...WITH THE ECMWF MAINTAINING PRECIP
CHANCES THROUGH SATURDAY AS THE FRONT STALLS NEAR THE REGION. FOR
NOW WILL SHOW PRECIP ENDING ON SATURDAY...BUT CLOUDY CONDITIONS
PERSISTING.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD AS AN INTENSIFYING
LOW PRESSURE SYSTEM TRACKS FURTHER OFFSHORE INTO THE ATLANTIC. THE
PRIMARY AVIATION CONCERN WILL BE BREEZY WNW/NW WINDS TODAY...
SUSTAINED AT 15 KT WITH GUSTS GENERALLY TO 25 KT...THOUGH A PERIOD
OF STRONGER WINDS SUSTAINED AT 20 KT WITH GUSTS UP TO 30 KT WILL BE
POSSIBLE...PRIMARILY BETWEEN 12-18Z...ESPECIALLY AT THE RWI
TERMINAL. WINDS WILL DECREASE TO 5-10 KT AFTER 21Z...BECOMING LIGHT
AND VARIABLE AFTER 00Z.
LOOKING AHEAD:
VFR CONDITIONS WILL RULE THROUGH MONDAY IN ASSOCIATION WITH DRY HIGH
PRESSURE. HIGH PRESSURE WILL MOVE OFFSHORE MONDAY NIGHT AS A COLD
FRONT APPROACHES THE MOUNTAINS FROM THE WEST. EXPECT DETERIORATING
CONDITIONS WITH MVFR/IFR CEILINGS DEVELOPING IN ASSOC/W AN
INCREASINGLY MOIST RETURN FLOW BETWEEN 06-12Z TUE AND INCREASING
CHANCES FOR RAIN FROM WEST-EAST BETWEEN 12-18Z TUE. A PERIOD OF
SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL BE POSSIBLE BETWEEN 06Z TUE
MORNING AND 18Z TUE AFTERNOON AS A 40-45 KT LLJ DEVELOPS AS LOW DOWN
AS 1500-2000 FT AGL. EXPECT RAPID CLEARING AND A RETURN TO VFR
CONDITIONS IN THE WAKE OF THE COLD FRONTAL PASSAGE LATE TUE INTO TUE
NIGHT. VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY AS DRY HIGH
PRESSURE BUILDS OVER THE CAROLINAS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
128 AM EST SUN FEB 17 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BUILD TOWARD THE CAROLINAS FROM THE
SOUTHWEST TODAY AS A RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM
OFFSHORE THE MID ATLANTIC COAST TRACKS NORTHEAST TOWARD THE CANADIAN
MARITIMES. HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT BEFORE
MOVING OFFSHORE LATE MONDAY INTO MONDAY NIGHT AS A COLD FRONT
APPROACHES THE MOUNTAINS FROM THE WEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 PM SATURDAY...
INTERESTING SNOW EVENT HERE FOR CENTRAL NC WITH WIDELY VARYING
TOTALS RANGING FROM ALMOST NOTHING (MELTED AS IT FELL) TO ABOUT TWO
AND A HALF INCHES. RAPID CLASSIC CYCLOGENESIS IS CURRENTLY TAKING
PLACE OFF THE NC COAST... NOTED WELL IN IR AND WATER VAPOR IMAGERY
BY THE DISTINCT BAROCLINIC LEAF STRUCTURE AND WITH A VERY STRONG
(170+ KT) UPPER JET CORE OFF THE COAST... AND BY THE INCREASE IN
LIGHTNING STRIKES EAST OF HATTERAS. WE STILL HAVE FOCUSED AREAS OF
SNOW... ONE OVER NORTHEAST SC ASSOCIATED WITH INTENSE DVPA
(OCCURRING WITH 500 MB VORTICITY MAX PASSAGE) AND UPRIGHT
INSTABILITY... WHILE ANOTHER BAND OF SNOW ROTATES ACROSS THE
NORTHEAST FORECAST AREA ASSOCIATED WITH A MID LEVEL DEFORMATION
BAND. THE FORMER FEATURE AND ITS VIGOROUS LIFT HAS LARGELY HELD
SOUTH OF THE NC/SC BORDER AS WAS SUGGESTED BY RECENT HRRR RUNS...
AND WILL CONTINUE TO MOVE ESE AWAY FROM CENTRAL NC. THE LATTER
FEATURE IS FORECAST TO WEAKEN AND SLIDE EASTWARD OVER THE NEXT FEW
HOURS... ALTHOUGH IT MAY DROP ANOTHER QUICK DUSTING TO ISOLATED HALF
INCH AMOUNTS IN AREAS NORTH AND EAST OF RALEIGH. SURFACE FLOW HAS
BECOME NORTHWESTERLY AND CYCLONIC OVER CENTRAL NC AND DOWNSLOPE
DRYING ALONG WITH INCREASING SUBSIDENCE BEHIND THE DEPARTING 850-700
MB TROUGH IS HELPING TO SCOUR OUT CLOUDS WEST TO EAST. THIS TREND
SHOULD CONTINUE WITH THE REMAINING LIGHT SNOW DIMINISHING THROUGH
08Z... ENDING LAST IN AREAS EAST OF RWI/GSB. THE INFLUX OF VERY DRY
AIR HAS BEEN IMPRESSIVE WITH DEW POINTS ALREADY HAVING DROPPED FROM
THE LOW 30S INTO THE LOW-MID TEENS IN THE TRIAD... AND THIS TREND
TOO SHOULD PERSIST INTO THE OVERNIGHT HOURS... AS THE DRY AIR
SPREADS EASTWARD WHILE TEMPERATURES DROP INTO THE 20S. WHILE 4 INCH
SOIL TEMPS ARE STILL SITTING IN THE LOW-MID 40S... ROAD SURFACES ARE
MARKEDLY COOLER... ESPECIALLY BRIDGES AND OVERPASSES WHICH ARE
LIKELY TO SEE SOME REFREEZING OF THE RESIDUAL WATER ON ROADS
OVERNIGHT. AS SUCH... THE EARLIER WINTER WEATHER ADVISORY FOR SNOW
HAS BEEN CANCELED EARLY... AND ANOTHER ADVISORY FOR BLACK ICE WILL
BE ISSUED FROM MIDNIGHT UNTIL 11 AM SUNDAY MORNING... WHEN TEMPS ARE
EXPECTED TO SURPASS THE FREEZING MARK OVER MUCH OF THE AREA. LOWS
TONIGHT 23-28. -GIH
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 240 PM SATURDAY...
THE SHORT TERM PERIOD WILL START WITH A COLD UPPER TROUGH OVER THE
EASTERN US...WHILE AT THE SURFACE...HIGH PRESSURE WILL GRADUALLY
BUILD IN BEHIND THE DEPARTING LOW THAT WILL BE TRACKING UP THE EAST
COAST. HIGHS ON SUNDAY WILL BE RATHER CHILLY...WITH TEMPS ONLY
RISING INTO THE MID/UPPER 30S TO LOWER 40S. IN ADDITION...WINDS WILL
BE QUITE BREEZY AS THE PRESSURE GRADIENT REMAINS TIGHT OVER THE AREA
BETWEEN THE DEPARTING AND DEEPENING LOW AND THE HIGH BUILDING IN.
THE PRESSURE GRADIENT WILL RELAX SUNDAY NIGHT AS THE HIGH BUILDS
NEARLY OVERHEAD AND GOOD RADIATIONAL COOLING CONDITIONS WILL SET
UP...ALLOWING OVERNIGHT LOWS TO FALL INTO THE LOW TO MID 20S. TEMPS
WILL BEGIN TO MODERATE ON MONDAY AS SHORTWAVE RIDGING BUILDS EAST
AND THE HIGH SLIPS OFFSHORE RESULTING IN A RETURN TO SOUTHERLY FLOW.
HIGHS IN THE UPPER 40S TO LOW/MID 50S ARE EXPECTED ON MONDAY...WITH
OVERNIGHT LOWS GENERALLY IN THE LOW/MID 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 240 PM SATURDAY...
SOUTHERLY FLOW WILL INCREASE AHEAD OF AN APPROACHING FRONT ON
TUESDAY AND THIS WILL ALLOW TEMPS TO WARM EVEN MORE...WITH HIGHS
POSSIBLY APPROACHING 60 DEGREES ACROSS THE SOUTHEAST. HOWEVER...
FURTHER TO THE NORTH AND WEST...INCREASING CLOUDS/PRECIP CHANCES
EARLIER IN THE DAY SHOULD HOLD TEMPS IN THE LOW/MID 50S (MAYBE EVEN
SOME UPPER 40S). THE FRONT IS EXPECTED TO CROSS THE REGION THROUGH
TUESDAY EVENING AND BRING WITH IT A GOOD CHANCE OF SHOWERS. BEHIND
THE FRONT...THERE SHOULD BE ENOUGH CLEARING TUESDAY NIGHT WHERE
TEMPS WOULD DROP INTO THE LOW/MID 30S.
SURFACE HIGH PRESSURE AND SHORTWAVE RIDGING WILL THEN DOMINATE THE
WEATHER ACROSS CENTRAL NC THROUGH THURSDAY. THIS WILL RESULT IN FAIR
WEATHER CONDITIONS AND NEAR NORMAL TEMPS. THE NEXT SYSTEM LOOKS TO
APPROACH THE AREA LATE THURSDAY NIGHT INTO FRIDAY. ALSO...THERE
CONTINUES TO BE INDICATIONS OF A CAD EVENT SETTING UP ACROSS THE
REGION AND THIS WILL HAVE TO BE MONITORED FOR POTENTIAL P-TYPE
ISSUES (ESPECIALLY AT THE ONSET OF ANY PRECIP) AND COOLER THAN
EXPECTED TEMPS...ESPECIALLY ACROSS THE NORTHWEST. FOR NOW...WILL
SHOW RAIN CHANCES INCREASING FROM WEST TO EAST DURING THE DAY ON
FRIDAY...WITH HIGHS RANGING FROM THE 40S ACROSS THE NORTHWEST TO
UPPER 50S (MAYBE NEAR 60 DEGREES) ACROSS THE EXTREME SOUTHEAST.
THERE IS UNCERTAINTY WITH RESPECT TO HOW QUICKLY THIS SYSTEM WILL
PROGRESS ACROSS THE REGION...WITH THE ECMWF MAINTAINING PRECIP
CHANCES THROUGH SATURDAY AS THE FRONT STALLS NEAR THE REGION. FOR
NOW WILL SHOW PRECIP ENDING ON SATURDAY...BUT CLOUDY CONDITIONS
PERSISTING.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD AS AN INTENSIFYING
LOW PRESSURE SYSTEM TRACKS FURTHER OFFSHORE INTO THE ATLANTIC. THE
PRIMARY AVIATION CONCERN WILL BE BREEZY WNW/NW WINDS TODAY...
SUSTAINED AT 15 KT WITH GUSTS GENERALLY TO 25 KT...THOUGH A PERIOD
OF STRONGER WINDS SUSTAINED AT 20 KT WITH GUSTS UP TO 30 KT WILL BE
POSSIBLE...PRIMARILY BETWEEN 12-18Z...ESPECIALLY AT THE RWI
TERMINAL. WINDS WILL DECREASE TO 5-10 KT AFTER 21Z...BECOMING LIGHT
AND VARIABLE AFTER 00Z.
LOOKING AHEAD:
VFR CONDITIONS WILL RULE THROUGH MONDAY IN ASSOCIATION WITH DRY HIGH
PRESSURE. HIGH PRESSURE WILL MOVE OFFSHORE MONDAY NIGHT AS A COLD
FRONT APPROACHES THE MOUNTAINS FROM THE WEST. EXPECT DETERIORATING
CONDITIONS WITH MVFR/IFR CEILINGS DEVELOPING IN ASSOC/W AN
INCREASINGLY MOIST RETURN FLOW BETWEEN 06-12Z TUE AND INCREASING
CHANCES FOR RAIN FROM WEST-EAST BETWEEN 12-18Z TUE. A PERIOD OF
SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL BE POSSIBLE BETWEEN 06Z TUE
MORNING AND 18Z TUE AFTERNOON AS A 40-45 KT LLJ DEVELOPS AS LOW DOWN
AS 1500-2000 FT AGL. EXPECT RAPID CLEARING AND A RETURN TO VFR
CONDITIONS IN THE WAKE OF THE COLD FRONTAL PASSAGE LATE TUE INTO TUE
NIGHT. VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY AS DRY HIGH
PRESSURE BUILDS OVER THE CAROLINAS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...HARTFIELD
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
459 AM EST SUN FEB 17 2013
.SYNOPSIS...
LOW PRESSURE WAS WELL OFF THE NEW JERSEY COAST THIS MORNING.
HIGH PRESSURE WAS CENTERED OVER MISSISSIPPI AND ALABAMA. THIS HIGH
WILL COVER MUCH OF THE MID ATLANTIC REGION AND SOUTHEAST UNITED
STATES THROUGH MONDAY MORNING. A COLD FRONT WILL MOVE INTO THE
AREA EARLY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 440 AM EST SUNDAY...
LATEST RAP AND LOCAL WRF CONTINUED TO SHOW BANDS OF SNOW SHOWERS
ACROSS THE MOUNTAINS...AND FOR A FEW HOURS THIS MORNING. SPILLING
INTO FRANKLIN...HENRY AND PATRICK COUNTIES. VISIBILITIES WERE
DROPPING TO AROUND A MILE UNDER THE HEAVY SNOW BANDS. HAVE SPREAD
THE FORECAST FOR ACCUMULATING SNOW LATER INTO THE MORNING FOR THE
WESTERN UPSLOPE COUNTIES AND THE NEW RIVER VALLEY.
BUFKIT SHOWED THE POTENTIAL FOR WIND GUSTS AROUND 40 KNOTS AT TNB
BUT ONLY 30 KNOTS FOR MOST OTHER LOCATIONS. NO WIND ADVISORY
PLANNED FOR NOW. JUST HIGHLIGHTED WINDS IN THE ONGOING WINTER
WEATHER ADVISORY.
850 MB TEMPERATURES THIS MORNING SHOULD BE IN THE -14 TO -18
DEGREE CELCIUS RANGE. HAVE ISSUED A WIND CHILL ADVISORY FROM
TAZEWELL COUNTY INTO GRAYSON COUNTY WHERE WINDS CHILLS WILL MEET
CRITERIA THIS MORNING.
SURFACE HIGH PRESSURE WILL BUILD OVER THE SOUTHEAST UNITED STATES
THIS AFTERNOON. THIS WILL RESULT IN DIMINISHING WINDS AND
DECREASING COVERAGE OF SNOW SHOWERS. ONCE THE SUN SETS...WIND
SPEEDS ARE EXPECTED TO DROP OFF TO LESS THAN 10 MPH SO EVEN THOUGH
OVERNIGHT LOW TEMPERATURES WILL AGAIN BE IN THE SINGLE DIGITS TO
AROUND 20...THE WIND CHILL WILL NOT BE A FACTOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
ON MONDAY...WE WILL HAVE ONE DRY AND MILDER...AND LESS WINDY DAY AS
HIGH PRESSURE BUILDS OVER THE REGION. WE EXPECTING HIGHS IN THE MID
TO UPPER 40S ACROSS THE MOUNTAINS WITH UPPER 40S EAST OF THE CREST
OF THE BLUE RIDGE.
MONDAY NIGHT THROUGH TUESDAY...A QUICK MOVING COLD FRONT WILL
APPROACH AND THEN CROSS THE REGION. WE WILL FIRST EXPERIENCE
INCREASING CLOUD COVER MONDAY EVENING...AND THEN PRECIPITATION WILL
MOVE INTO THE REGION FROM THE WEST AFTER MIDNIGHT AHEAD OF THE COLD
FRONT. THE PRECIPITATION WILL BE ACCOMPANIED BY A WARM NOSE ALOFT
OVER A MIX OF ABOVE AND BELOW TEMPERATURES AT THE SURFACE. MODEL
GUIDANCE HAS TRENDED COLDER WITH THE MAGNITUDE OF THE WARM NOSE. WE
ARE SEEING A TREND TOWARDS MORE SNOW AND SLEET ACROSS THE MOUNTAINS
AND THE NORTHERN THIRD OF THE FORECAST AREA LATE MONDAY NIGHT INTO
EARLY TUESDAY MORNING. AFTER ROUGHLY 9 OR 10 AM
TUESDAY...TEMPERATURES WILL BE MILD ENOUGH FOR MOST OF THE AREA TO
RECEIVE RAIN. THERE STILL MAY BE SOME SNOW IN WESTERN GREENBRIER
COUNTY WV THROUGH THE DAYTIME TUESDAY. BY TUESDAY AFTERNOON...THE
COLD FRONT WILL BE HEADING EAST OF THE FORECAST AREA AND THE
PRECIPITATION WILL BEGIN TO BECOME CONFINED TO THE UPSLOPE REGIONS
OF SOUTHEAST WEST VIRGINIA. AS WE HEAD INTO TUESDAY NIGHT...THIS
PRECIPITATION WILL QUICKLY TRANSITION INTO SNOW SHOWERS...BUT
TREND TOWARDS DECREASING COVERAGE THROUGH THE NIGHT. THE REMAINDER
OF THE FORECAST AREA WILL BE PRECIPITATION FREE.
WE ARE STILL CONCERNED ABOUT GUSTY/DAMAGING WINDS AHEAD OF THE FRONT
ON TUESDAY AND THEN BEHIND THE FRONT TUESDAY NIGHT. MODEL GUIDANCE
PLACES A SOUTHWEST 850 MB JET AROUND 60 TO 65 KTS JUST IN ADVANCE OF
THE FRONT. SOME STRONGER GUSTS MAY BE ABLE TO ACCOMPANY THE HEAVIER
SHOWERS TO THE SURFACE. TUESDAY NIGHT...NORTHWEST 850 MB WINDS OF 50
KTS ARE EXPECTED BY MIDNIGHT...AND 50 TO 60 KTS ARE EXPECTED BY
SUNRISE WEDNESDAY. CONFIDENCE IS GROWING FOR THE POTENTIAL FOR AT
LEAST A WIND ADVISORY TUESDAY AND THEN AGAIN TUESDAY NIGHT INTO
EARLY WEDNESDAY.
WEDNESDAY INTO WEDNESDAY NIGHT...A DRY FORECAST IS EXPECTED AND
WINDS WILL EXPERIENCE A GRADUAL DECREASE AS THE CENTER OF HIGH
PRESSURE DRAWS CLOSER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 320 PM EST SATURDAY...
BY THURSDAY AFTERNOON...AN INVERTED TROUGH WILL DEVELOP ACROSS
EASTERN KENTUCKY AND WEST VIRGINIA. THIS WILL ALLOW THE WINDS TO
BECOME EASTERLY WITH UNIFORM TEMPERATURES IN THE 40S ACROSS THE
AREA.
A WARM FRONT WILL OVERRUN THIS SURFACE RIDGE THURSDAY NIGHT WITH
PRECIPITATION TRACKING FROM SOUTHWEST TO NORTHEAST. THIS
PRECIPITATION WILL BE FALLING INTO DRY AIR WITH DEW POINTS IN THE
UPPER TEENS TO MID 20S. INITIAL P-TYPE WILL BE A BRIEF PERIOD OF
SLEET FOLLOWED BY RAIN AND FREEZING RAIN. FORECAST SOUNDINGS
CONTINUES TO SUPPORT FREEZING RAIN FRIDAY MORNING. CHANCES OF
FREEZING RAIN ARE MORESO ALONG THE EASTERN SLOPES OF THE BLUE
RIDGE AND POSSIBLY ACROSS THE GREENBRIER AND SOUTH SHENANDOAH
VALLEY. CONVECTION TRACKING ACROSS THE SOUTHEASTERN US MAY KEEP
RAIN/ICE AMOUNTS LOWER THAN CURRENTLY FORECASTED BY THE MODELS.
THE GFS/ECMWF HAS A QUARTER TO A HALF INCH OF LIQUID WITH THIS
SYSTEM.
BULK OF THE PRECIPITATION WILL MOVE EAST FRIDAY
AFTERNOON...HOWEVER...THE INSITU WEDGE WITH COLD...GRAY...DAMP
CONDITIONS MAY LINGER ACROSS THE PIEDMONT INTO FRIDAY NIGHT. AS
THE WEDGE BREAKS...TEMPERATURES WILL WARM ABOVE FREEZING. FOG
COULD THEN BECOME A PROBLEM FRIDAY NIGHT INTO SATURDAY MORNING. BY
SATURDAY AFTERNOON...THE WINDS BECOME WESTERLY WITH TEMPERATURES
POSSIBLY WARMING ABOVE NORMAL.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
AS OF 1205 AM EST SUNDAY...
NORTHWEST FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION TONIGHT
THROUGH SUNDAY. BANDS OF SNOW SHOWERS ARE OCCURRING ACROSS THE
MOUNTAINS...AND THESE WILL CONTINUE...BUT TREND TOWARD DECREASING
COVERAGE AFTER SUNRISE. LOCALIZED IFR CONDITIONS ARE EXPECTED
WITHIN THE HEAVIER BANDS...WITH VFR CONDITIONS THE NORM ELSEWHERE.
SURFACE GUSTS IN THE MOUNTAINS WILL INCREASE TO AROUND 25 KTS BY
12Z/7AM WITH READINGS AROUND 30-35 KTS NEAR THE CREST OF THE BLUE
RIDGE BY 15Z/10AM. WINDS WILL GRADUALLY DECREASE DURING SUNDAY
AFTERNOON...BUT THE NOTABLE DECREASE WILL OCCUR AROUND SUNSET AS
BOTH THE NOCTURNAL INVERSION DEVELOPS AND WINDS ALOFT START TO
DECREASE IN SPEED.
HIGH PRESSURE WILL BUILD IN FOR SUNDAY NIGHT AND MONDAY...BUT HE
BREAK WILL BE SHORT LIVED AS LOW PRESSURE MOVING INTO THE GREAT
LAKES REGION WILL PUSH A COLD FRONT THROUGH THE AREA ON
TUESDAY...WITH PCPN AHEAD OF THE FRONT MAKING ITS WAY INTO THE TAF
SITES LATE MONDAY NIGHT. EXPECT IFR CONDITIONS WITH PCPN AND WINDY
CONDITIONS WITH FROPA ON TUESDAY AND WINDS CONTINUING BEHIND THE
FRONT ON WEDNESDAY. HIGH PRESSURE WILL THEN BUILD IN FOR THURSDAY
ALLOWING A BRIEF SPELL OF VFR.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR VAZ007-
009-010-012-015.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ001-018.
WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
WVZ045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...RCS
AVIATION...AMS/DS/JH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CST SAT FEB 16 2013
.SHORT TERM...THROUGH TUESDAY NIGHT
326 PM CST SAT FEB 16 2013
MUCH OF THE TIME TODAY WAS SPENT WORKING ON MONDAY INTO TUESDAY.
IMPACTS LOOK TO BE MINIMAL AS MAIN PRECIPITATION REGION LOOKS TO
ADVECT IN JUST EAST OF THE FORECAST AREA.
CLOUDS HAVE BEEN A TOUGH FORECAST AS OF LATE...AND TONIGHT THEY
COULD HAVE A HUGE IMPACT ON LOW TEMPERATURES. CURRENT GOES
SATELLITE IMAGERY SHOWING CLOUDS EXPANDING IN WRN MN WEST OF THE
SURFACE RIDGE AXIS FROM KINL TO KALO. MAINLY CUMULUS FIELDS
ARE AFFECTING THE FORECAST AREA WITH THOSE EXPECTED TO DISSIPATE
BY LATE AFTERNOON. SURFACE OBSERVATIONS SHOWING A STATIONARY FRONT
LOCATED FROM ABOUT KFSD-KDSM WITH WARM AIR TO THE SOUTHWEST AND
CONVERGENT FLOW INTO NE IA.
GOES WATER VAPOR SHOWING THE MONDAY S/WV WELL NOW COMING ONTO THE
WEST COAST WITH THE NRN ENERGY OVER BRITISH COLUMBIA AND THE
16.19Z RAP INDICATING A TROPOPAUSE FOLD TO 400MB INTO THE OR
COAST REPRESENTING THE SRN ENERGY THAT IS FORECAST TO DIG INTO THE
CENTRAL U.S. KUIL WASHINGTON RAOB HAD A 150M/12HR HEIGHT FALL THIS
MORNING AHEAD OF THIS POTENT SHORTWAVE TROUGH.
HAVE LOWERED THE LOW TONIGHT ACROSS CENTRAL WI AS THE SURFACE
RIDGE WILL BE RIGHT OVERHEAD MOST OF THE NIGHT AND CLOUDS ARE
FORECAST TO REMAIN MINIMAL. HAVE DROPPED LOWS 5-7F THERE TONIGHT
FROM PREVIOUS FORECAST. CLOUDS ARE TOUGH THOUGH AND AM THINKING
TWO AREAS COULD DEVELOP STRATUS...CURRENT HEAVY CUMULUS AREA OVER
NRN WI AND CONVERGENT BOUNDARY ACROSS IA. THE NRN WI AREA COULD
EXPAND OVER NRN FORECAST AREA LATE AND CLOUDS WILL ALSO SPREAD IN
FROM THE SW. THUS...LOW CONFIDENCE IN FORECAST CLOUDS AND LOWS
TONIGHT...BUT FORECASTING THE CENTRAL FORECAST AREA TO REMAIN
MOSTLY CLEAR.
WARM ADVECTION TO KICK IN SUNDAY AND PEAK SUNDAY NIGHT WITH
WARMING OCCURRING INTO MONDAY WEATHER SYSTEM. 16.12Z MODEL
CONSENSUS IS TO STILL DEVELOP THE NRN CYCLONE THE MOST...NORTH OF
THE GREAT LAKES...WITH THE SRN ENERGY CAUSING WEAK CYCLOGENESIS
ALONG THE FRONTAL BOUNDARY AS IT PASSES TO THE SE OF THE FORECAST
AREA. SOME SPREAD STILL REMAINS IN THE GUIDANCE. THE 16.12Z NAM
REMAINS CONSISTENT WITH IT/S PREVIOUS RUNS OF THE DRY OUTLIER. THE
16.12Z CANADIAN GLOBAL GEM STILL INSISTS ON A WET 0.30 INCHES
AREA-WIDE WITH THIS SYSTEM /AND HIGHS IN THE 40S/. STILL PREFER THE
CONSISTENT ECMWF/GFS RUNS ON THE OUTCOME FOR THIS SYSTEM. IT
APPEARS THE MAIN MOISTURE AXIS WILL ONLY GRAZE THE ERN FORECAST
AREA FROM CENTRAL WI TO SWRN WI...A STEP EAST FROM PREVIOUS MODEL
RUNS. THIS SAME AREA WILL SEE THE DEEPEST SURFACE-BASED SATURATION
COME IN MONDAY MORNING /KOVS 0-2 KM/...WITH THE LAYER MORE SHALLOW
FURTHER TO THE NW /KEAU 1KM/. NW OF THE SURFACE WAVE...WOULD THINK
A BIT OF ENHANCEMENT IN THE DEFORMATION WILL OCCUR AND HAVE KEPT
HIGHEST PRECIPITATION CHANCES IN THAT SWRN-CENTRAL WI
AREA...TAPERING LOWER TO THE NORTHWEST.
IT APPEARS DEEP SATURATION TO COLDER THAN -10C TO GET ICE GROWTH WILL
BE TROUBLESOME/SPOTTY OR JUST PLAIN HARD TO FORECAST WITH THIS
SYSTEM. THE Q-G FORCING IS MODERATE ALOFT AND WEAKER IN THE LOW
LEVELS PROVIDING OVERALL A WEAK BUT PRESENT LIFT SIGNAL. BUT
REVIEWING MODEL SOUNDINGS FROM THE 16.09Z SREF AND 16.12Z NAM/GFS
THERE IS CONSISTENT STRUGGLES WITH SATURATION NOTED...AND THUS
HAVE GONE WITH A MAJORITY OF LIQUID IN THE FORECAST UNTIL THE COLD
FRONT MOVES IN LATER MONDAY WITH VERY STRONG COLD ADVECTION TO DRIVE
THE ICE PROCESS AND SNOW CONVERSION. THIS SATURATION STRUGGLE AWAY
FROM THE SURFACE WAVE IS ALSO WHY PRECIPITATION CHANCES ARENT
HIGHER FOR THIS FORECAST.
MONDAY MORNING WILL SEE THE MOISTURE INCREASE AND SURFACE TEMPERATURES
WARMING TO NEAR OR ABOVE FREEZING IN THE AFTERNOON. THIS WILL
CAUSE A FZDZ POSSIBILITY MAINLY IN THE MORNING IF THE LAYER CAN
PRECIPITATE...PROBABLY VERY LIGHT AMOUNTS AROUND 0.01-0.02 INCHES
TO PROVIDE A LIGHT GLAZE AFTER COMMUTE TIME. MANY AREAS SOUTH OF
I-90 WILL WARM TO ABOVE FREEZING BY MID-DAY...ESPECIALLY CLOSE TO
THE MOIST AXIS SO IMPACTS WOULD BE MINIMAL THERE...OR AT LEAST
SHORT LIVED. HAVE KEPT FZDZ STILL POSSIBLE FOR POINTS WITH AIR
TEMPERATURES OF 35F OR COLDER AS ROADS MAY STILL BE SLOWER TO
RECOVER TO ABOVE FREEZING.
THE NORTHERN AND WESTERN AREAS COULD SEE FZDZ PERIODICALLY MONDAY
THROUGH THE DAY...POSSIBLE MIXING WITH SNOW AS SATURATION OCCURS
IN A PATCHY WAY. THE COLD FRONT WILL SWEEP IN WITH VERY STRONG
COLD ADVECTION CONVERTING ALL LIGHT LIQUID PRECIPITATION TO SNOW.
WITH THE COLD ADVECTION STRONG...LAPSE RATES IN THE LOWEST 1 KM
ARE QUITE STEEP AND WILL PROMOTE WIND GUSTS IN THE 25 TO 35 MPH
RANGE LATE MONDAY AND OVERNIGHT. HAVE INCREASED THE WINDS WITH
THIS FORECAST BASED ON 16.12Z NAM/GFS BLEND.
OVERALL...COMFORT REMAINS LOW ON THIS SYSTEM /I HAVE MORE
CONFIDENCE IN THE THU-FRI SNOW/ BUT MY FEELING IS THAT THE IMPACTS
WILL BE MINOR. DO NOT FEEL A NEED FOR A HEADLINE ON THIS SYSTEM AS
THE LIQUID AMOUNTS LOOK TO BE PRETTY LIGHT. IN THE DEFORMATION
AREA TEMPERATURES WOULD BE WARMEST AND MAINLY RAIN WOULD FALL. BUT
THERE ARE SOME HINTS THAT UP TO A TENTH OF PRECIPITATION COULD
FALL MONDAY AWAY FROM THE MOISTURE AXIS /KEAU SREF MEAN GIVES 0.07
OF FZDZ/ SO IT IS STILL A SYSTEM TO WATCH.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
326 PM CST SAT FEB 16 2013
THE FOCUS REMAINS ON THE INCREASINGLY ADVERTISED LATE WEEK SYSTEM
AND THE DEGREE OF IMPACT IT WILL HAVE ON THE UPPER MIDWEST. LEADING
UP TO THAT FEATURE...WEDNESDAY LOOKS TO BE A TRANSITION DAY WITH
MORNING COLD ADVECTION AS A SURFACE HIGH AND UPPER LEVEL RIDGE AXIS
REMAINS TO THE WEST OF THE FORECAST AREA. A COLD DAY ON TAP AS
MORNING LOWS IN THE SINGLE DIGITS BELOW/ABOVE ZERO LOOK TO RISE INTO
ONLY THE TEENS. THE RIDGE IS THEN EXPECTED TO BUILD ACROSS BY
WEDNESDAY NIGHT...LEADING TO RETURN SOUTHERLY FLOW. A WESTERN CONUS
TROUGH THEN DIGS AND MOVES EAST...EJECTING THE MAIN SHORTWAVE
TROUGH OUT OF THE COLORADO ROCKIES BY 12Z THURSDAY. SURFACE LOW
DEEPENS RAPIDLY ACROSS THE CENTRAL PLAINS THURSDAY...LIFTING
TOWARD THE AREA.
THE 16.12Z GFS ENSEMBLE REMAINS CLOSELY PACKED WITH A LOW TRACK
ALONG A KANSAS CITY TO NORTHERN ILLINOIS LINE THURSDAY NIGHT INTO
FRIDAY AFTERNOON. THE 16.12Z ECMWF TOOK A STEP NORTHWEST WITH ITS
SURFACE LOW TRACK AND THE 16.12Z GEM AND FIM REMAIN THE SOUTHERLY
OUTLIERS. THE GFS SEEMS TO BE A GOOD COMPROMISE. EARLIER TIMING
ISSUES APPEAR TO BE RESOLVED FOR NOW. YESTERDAY/S CONCERNS ABOUT THE
FILLING UPPER LEVEL TROUGH / SURFACE LOW AND ITS IMPACT WERE MUTED
SLIGHTLY SINCE THE 16.12Z GFS...ECMWF AND FIM CAME IN A BIT
STRONGER. HOWEVER...500 MB HEIGHT STANDARDIZED ANOMALIES STILL RISE
FROM -3.5 ACROSS THE CENTRAL PLAINS...TO AROUND -0.5 BY 12Z FRIDAY
WHICH SUGGESTS A WEAKENING TREND AND THE SYSTEM NOT NEARLY AS WOUND
UP AS IT MAY BE IN THE CENTRAL PLAINS.
PRECIPITATION WOULD OVERSPREAD THE AREA DURING THE AFTERNOON
THURSDAY...WITH THE MAIN WARM ADVECTIVE WING SWINGING THROUGH
THURSDAY NIGHT AND OVERNIGHT FRIDAY. THIS WOULD BE WHEN THE HIGHEST
SNOW RATES OCCUR. AS THE SURFACE LOW THEN MOVES NEARBY...WRAP AROUND
/ DEFORMATION BANDING SNOW WOULD LINGER THROUGHOUT FRIDAY. SOUNDINGS
STILL POINT TO AN ALL SNOW EVENT WITH THE WARMEST AIR REMAINING
SOUTH OF THE AREA.
THE MODEL CONSISTENCY AND RUN-TO-RUN SIMILARITIES REMAIN VERY ABOVE
AVERAGE AND REMARKABLE FOR IT STILL BEING 6 DAYS OUT. GIVEN THE
FEATURE IS CURRENTLY OVER THE DATA SPARSE NORTHERN PACIFIC...THERE
CERTAINLY WILL BE FINE-TUNE DETAILS TO ESTABLISH. PRECIPITATION
AMOUNTS TOOK A STEP UP IN THE LATEST ROUND OF GUIDANCE THOUGH STILL
REMAIN BETWEEN 0.7 TO 1.0 INCH. CONFIDENCE CONTINUES TO GROW IN A
WARNING LEVEL EVENT WITH WIDESPREAD 6 TO 10 INCH AMOUNTS IF THE
CURRENT AND PAST SOLUTIONS INDEED VERIFY. THE BIG PICTURE IS THAT
THOSE WITH INTERESTS AND TRAVEL CONCERNS LATE NEXT WEEK SHOULD
CONTINUE TO MONITOR AND FOR NOW...HAVE CONTINUED TO PUSH HIGHER
PRECIPITATION CHANCES THURSDAY NIGHT...AND TRENDED FRIDAY HIGHER AS
WELL SINCE IF THE SYSTEM DOES SLOW DOWN / FILL IN THEN THERE WOULD
CERTAINLY BE LINGERING DEFORMATION BANDING SNOW ACROSS MUCH OF THE
AREA. THE PROLONGED DURATION / THURSDAY NIGHT THROUGH LATE FRIDAY
NIGHT / COULD PRESENT SOME CHALLENGES FOR TRAVELERS AND ROAD CREWS
AS WELL.
&&
.AVIATION...THROUGH 06Z MONDAY
1100 PM CST SAT FEB 16 2013
BAND OF VFR STRATUS APPROACHING INTERSTATE 35 IS A LITTLE LESS
EXPANSIVE THAN PREVIOUSLY THOUGHT TO THIS POINT...BUT PERSISTENT
WARM AIR AND SOME MOISTURE SHOULD EVENTUALLY RESULT IN EITHER A
SCATTERED OR BROKEN DECK CROSSING THE TAF SITES TODAY. BASES LOOK
TO BE AT OR ABOVE 6000 FT. FARTHER TO THE WEST...AN AREA OF MVFR
STRATUS EXISTS OVER EASTERN SOUTH DAKOTA. AS LOW LEVEL WINDS TURN
MORE SOUTH TO SOUTHWEST TODAY...THIS LOW STRATUS DECK LOOKS TO
LIFT TO THE NORTHEAST...THUS STAYING AWAY FROM THE TAF SITES.
OTHERWISE...THE ONLY CLOUDS TO CONTEND WITH WILL BE SOME
CIRROSTRATUS DROPPING SOUTH OUT OF NORTH DAKOTA.
WINDS ARE AN ISSUE FOR THE FORECAST. THE PRESSURE GRADIENT IS
FORECAST TO TIGHTEN OVER THE TAF SITES TODAY INTO THIS
EVENING...IN RESPONSE TO LOW PRESSURE APPROACHING THE AREA FROM
THE PLAINS. SOUTHEAST WINDS LOOK TO KICK UP TO 10-20 KT WITH GUSTS
OF 15-25KT. THE STRONGEST WINDS AND BULK OF THE GUSTS WILL OCCUR
AT KRST WHERE THE GRADIENT IS TIGHTEST AND THE AIR CAN STAY MORE
MIXED. AT KLSE...AFTER A BRIEF PERIOD OF GUSTS IN THE AFTERNOON...
COOLING IN THE EVENING IS EXPECTED TO ALLOW FOR LOW LEVEL WIND
SHEAR TO DEVELOP. SOUTH WINDS OF 40-50 KT ARE SUGGESTED BETWEEN
1500-2000 FT FOR MUCH OF TONIGHT AT BOTH TAF SITES...BUT THE
STRONGER SURFACE WINDS AT KRST PRECLUDES THE NEED FOR LOW LEVEL
WIND SHEAR THERE.
LOOKING AHEAD...LOW CLOUDS ALONG WITH A LIGHT WINTRY MIX COULD
IMPACT BOTH TAF SITES ON MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
151 PM CST SAT FEB 16 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM...TAYLOR
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1033 PM CST SAT FEB 16 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SYNOPSIS...
ISSUED AT 223 PM CST SAT FEB 16 2013
MODERATING TEMPS WITH SOME LIGHT TO MODERATE PRECIPITATION MONDAY
NIGHT AND TUESDAY. STILL PLENTY OF QUESTIONS ABOUT THE NEXT SYSTEM
EXPECTED TO ARRIVE LATE IN THE WEEK.
UPR FLOW ACRS NOAM WL START OUT WITH A BROAD RIDGE OVER THE ERN
PAC/WRN NOAM...ALBEIT WITH STG SHRTWV RIGHT IN THE MIDDLE OF THE
RIDGE POSN. A DEEP TROF WAS OVER ERN NOAM...WITH RIDGING OVER THE
WRN ATL. THE SHRTWV NOW IN THE WRN RIDGE POSN AND ITS SUCCESSOR WL
BOTH DIG PROGRESSIVELY FARTHER W...EVENTUALLY PULLING THE MEAN
TROF POSN BACK INTO THE WESTERN CONUS BY MID-WK. MEANWHILE...THE
DOWNSTREAM PATTERN OVER THE ATL WL BREAK DOWN INTO A COMPLEX
BLOCKING REGIME. THE BLOCKING WL EVOLVE WWD WITH TIME...
RESULTING IN A SPLIT FLOW ACRS MUCH OF THE CONUS BY NEXT WEEKEND.
THE TWO MAJOR SHRTWVS WORKING ACRS THE CONUS DURING THE PERIOD WL
BOTH SUPPORT STG CYCLONES. THE CHANGING UPR PATTERN AND PASSAGE OF
THE CYCLONES WL TAKE TEMPS ON A ROLLERCOASTER RIDE DURING THE
PERIOD. THEY/LL START OUT COLD...QUICKLY WARM EARLY IN THE WEEK...
DROP BACK TO BLO NORMAL MID-WEEK...THEN SETTLE BACK CLOSER TO
NORMAL AS THE FLOW SETTLES INTO SPLIT REGIME. GIVEN THE 2 SIG
SYSTEMS LIKELY TO IMPACT THE AREA...PCPN AMNTS WL PROBABLY END UP
AOA NORMAL.
&&
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 223 PM CST SAT FEB 16 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE RIDGE STRETCHING FROM TEXAS TO ONTARIO THIS AFTERNOON.
STEEPENING LOW LEVEL LAPSE RATES AND FLOW OFF SUPERIOR CONTRIBUTED
TO A WIDESPREAD DIURNAL CU FIELD...WHICH SPREAD SOUTH ACROSS MUCH
OF THE CWA BY EARLY THIS AFTERNOON. LAKE EFFECT SNOW SHOWERS
REMAINED CONFINED TO NORTHERN VILAS COUNTY AND POINTS NORTH AND
VSBYS IN THIS AREA SUGGEST ONLY MINOR ACCUMS AT BEST. PRETTY QUIET
UPSTREAM AS WELL. FGEN INDUCED BAND OF CLOUDS AND LIGHT SNOW OVER
THE PLAINS IS SLIDING SE WHILE SKY CONDITIONS ARE CLEARING OVER
MINNESOTA. CLOUD TRENDS AND TEMPS ARE THE MAIN FORECAST CONCERNS
IN THE SHORT TERM.
TONIGHT...SURFACE HIGH PRESSURE TO MOVE ACROSS THE REGION AND
THIS SHOULD RESULT IN LOW LEVEL FLOW BECOMING LIGHT THIS EVENING.
ANTICIPATING STRATO-CU TO RAPIDLY DIMINISH WITH LOSS OF DAYTIME
HEATING EARLY THIS EVENING...EXCEPT OVER NORTH-CENTRAL WISCONSIN
WHERE IT SHOULD TAKE A FEW HOURS LONGER. AS A RESULT...EXPECT SKY
CONDITIONS TO BECOME CLEAR TO MOSTLY CLEAR ACROSS THE REGION BY
LATE THIS EVENING. STRATUS UPSTREAM THIS MORNING BENEATH THE RIDGE
AXIS SEEMED ALIGNED WITH A LOW LEVEL THERMAL GRADIENT. THIS
GRADIENT DOES NOT MOVE MUCH TONIGHT...SO AM NOT EXPECTING CLOUDS
TO REFORM BENEATH THE SURFACE HIGH. TEMPS LAST NIGHT FELL INTO THE
TEENS BELOW ZERO OVER N-C WISCONSIN. SHOULD HAVE LIGHTER WINDS IN
THE BOUNDARY LAYER AND THE PWAT MINIMUM OVERHEAD...SO HAVE DROPPED
TEMPS FROM THE PREVIOUS FORECAST.
SUNDAY...HIGH PRESSURE MOVES EAST OF THE REGION AND RETURN FLOW
WILL PUSH A WARM FRONT INTO THE NORTHERN MISSISSIPPI VALLEY BY THE
AFTERNOON. THOUGH MID AND HIGH CLOUDS WILL BE INCREASING THROUGH
THE DAY...DEEPER MOISTURE WILL STAY WELL OFF TO THE NORTHWEST OVER
NORTHERN MINNESOTA AND SOUTH-CENTRAL CANADA. HIGHS WILL BE
CONSIDERABLY WARMER THAN TODAYS READINGS...AND MOSTLY RANGE FROM
THE LOWER TO MIDDLE 20S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 223 PM CST SAT FEB 16 2013
WAA ON THE BACK SIDE OF DEPARTING RIDGE WL KICK INTO HIGH GEAR
SUN NGT. THE STRONGEST ISENT LIFT AND BEST CHC AT SATURATION WL BE
ACRS THE N. WENT WITH CHC POPS THERE...AND KEPT THE S DRY. EXPECT
EVENING MINS THEN RISING TEMPS.
COMPLEX STORM SYSTEM DRIVEN BY PHASING SHRTWVS WL BE ORGANIZING
AS IT CROSSES THE AREA MON...THEN DEEPEN JUST OFF TO OUR E MON NGT
INTO TUE. RAISED POPS AS FORCING LOOKS FAIRLY STG. BUT MOISTURE WL
BE LIMITED...ESP INITIALLY. THAT WL PROBABLY RESULT IN ANOTHER
EVENT WITH MESSY MIX OF SN/DZ/FZDZ DEPENDING ON WHETHER SUFFICIENT
MID-LVL MOISTURE IS PRESENT AT ANY TIME TO SEED THE LOWER CLDS FM
ABV. MODEL FCST SOUNDINGS SUGGEST LOWER-LEVELS OVER E-C WI COULD
BRIEFLY BE WARM ENOUGH FOR JUST RAIN MON AFTN EVEN IF MOISTURE IS
DEEP AT THAT TIME. WENT WITH MAINLY SN/FZDZ ACRS THE NW AND RA/SN
IN THE SE ON MON. E-C WI COULD CERTAINLY SEE DZ RATHER THAN
RAIN... BUT WANTED TO AVOID HAVING TOO MANY PCPN TYPES IN THE
FCST.
PCPN SHOULD CHG TO SNOW MON NGT...WITH SHSN ON THE BACK SIDE OF
THE SYSTEM CONTG INTO TUE. UPPED POPS AS UPR TROF WL BE SHARPENING
RIGHT ACRS THE AREA DURING THAT TIME. THINKING RIGHT NOW IS THAT
THIS WL BE A 1-3 INCH EVENT...WITH THE HIGHER TOTALS IN THE NE.
LAKE-EFFECT OFF LAKE SUPERIOR COULD BOOST TOTALS EVEN FURTHER OVER
THE SNOWBELT...THOUGH THAT DEPENDS ON EXACT TRAJECTORIES SO WON/T
GET TOO SPECIFIC WITH THAT YET.
A BREAK FM THE SIG PCPN THEN EXPECTED WED INTO THU AS UPR RIDGE
SHARPENS ACRS THE AREA. STG...COLD...VERY DRY LOW-LEVEL
ANTICYCLONE WL BE RIDGING SWD INTO THE RGN FM THE HUDSON BAY AREA.
LOW-LEVEL WINDS WL VEER ARND TO THE E...AND ALTHOUGH THE UPSTREAM
AIR WL BE VERY DRY AND INVERSION HEIGHTS WL BE LOW...WL PROBABLY
GET SOME LAKE FLURRIES INTO E-C WI.
STILL A LOT OF QUESTIONS ABOUT THE SYSTEM HEADING INTO THE AREA
DURING THE LATTER PART OF THE WEEK. DON/T LIKE THAT THE SYSTEM WL
BE DRIVING INTO A DOWNSTREAM BLOCK AND HAVE VERY DRY AIR FEEDING
INTO IT FM THE E AT LOW-LEVELS. THAT/S A CLASSIC LATE WINTER/EARLY
SPRING FCST PROBLEM HERE...AND IT TYPICALLY RESULTS IN A CONSTANT
DELAYING OF THE ONSET OF PCPN...AND OFTEN A REDUCTION IN PCPN
TOTALS. ON THE OTHER HAND...IF SYSTEM CAN GET PCPN INTO THE
AREA...DOWNSTREAM BLOCKING WL CAUSE IT TO SLOW TO A CRAWL...AND
RESULT IN A LONG-DURATION EVENT.
FEELING RIGHT NOW IS THAT THIS IS A SYSTEM THAT WL HAVE IT/S
GREATEST IMPACT OUT IN THE PLAINS. MAX SNOWS WL PROBABLY END UP IN
THE SW PART OF THE FCST AREA...AND THEY WILL PROBABLY BE
CONSIDERABLY LESS THAN WHAT FALLS TO OUR SW. AT THIS POINT...WAS
CONTENT WITH INITIALIZATION GRIDS THAT NEVER WENT BEYOND LIKELY
POPS. CERTAINLY PLENTY OF TIME FOR LATER SHIFTS TO ADJUST FCST.
WL CONT TO MENTION SYSTEM IN THE HWO...BUT DON/T PLAN ON PLAYING
THIS UP AS A BIG STORM.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH AN INCREASE OF
MID LEVEL CLOUDS AS WARMER AIR WORKS NORTH INTO THE REGION ON
SUNDAY AND SUN EVENING. STRONG LOW LEVEL WINDS FROM THE SOUTHWEST WILL
LEAD TO LOW LEVEL WINDSHEAR DURING THE EVENING WEST...EAST AROUND MIDNIGHT.
TE
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1031 AM EST SUN FEB 17 2013
.SYNOPSIS...
SNOW SHOWERS WILL DECREASE IN COVERAGE TODAY. HIGH PRESSURE WILL
THEN BUILD IN TONIGHT WITH DRY AND WARMER WEATHER ARRIVING ON
MONDAY. A COLD FRONT WILL THEN RETURN RAIN AND SNOW TO THE AREA ON
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED THIS MORNING TO
UPDATE THE WINTER WEATHER HEADLINES...EXPANDING THE ADVISORY FOR
THE RIDGES UNTIL 21Z...AND ADDING THE MENTION OF STORM TOTAL
AMOUNTS.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A MID-LEVEL TROUGH
AXIS CENTERED ACROSS EASTERN PA...LEAVING THE UPPER OHIO VALLEY IN
A NORTHWESTERLY FLOW IN THE WAKE OF THIS FEATURE. AT 850MB...A
NORTH-NORTHWESTERLY FLOW IS IN PLACE ACROSS THE LOWLANDS...WITH
MORE OF WESTERLY COMPONENT ACROSS THE LAUREL HIGHLANDS AND
ALLEGHENY FRONT OF WV/PA/MD. AT THE SURFACE...A LOW PRESSURE
SYSTEM IS OFF THE COAST OF NEW ENGLAND WITH A BROAD AREA OF HIGH
PRESSURE EXTENDING FROM THE UPPER MIDWEST TO THE GULF OF MEXICO.
THE COMBINATION OF WEAK VORT ENERGY SWINGING SOUTHEASTWARD ON THE
BACK END OF THE TROUGH ALONG WITH MOISTURE FILTERING IN FROM LAKE
HURON HAS ALLOWED SCATTERED SNOW SHOWERS TO CONTINUE ACROSS MUCH
OF THE AREA...WITH MORE WIDESPREAD SNOW SHOWERS WITH UPSLOPING
ACROSS THE RIDGES.
THIS AFTERNOON...THE UPPER TROUGH WILL PUSH OFF THE EAST COAST
WITH THE AREA REMAINING IN A NORTHWESTERLY FLOW AS HIGH PRESSURE
BEGINS TO BUILD IN FROM THE SOUTHWEST. VORT ENERGY SLIDING
EASTWARD WILL ALLOW FOR SNOW SHOWERS TO CONTINUE...BUT MOISTURE
WILL BECOME MORE SHALLOW WITH AN INVERSION LOWERING THIS
AFTERNOON...ALLOWING FOR SNOWFALL TO CONTINUE TO DECREASE IN
COVERAGE AND DIMINISH. UPSLOPING WILL ALLOW FOR ACCUMULATING
SNOWFALL TO CONTINUE IN THE EASTERN RIDGES...WITH AN ADDITIONAL 1
TO 3 INCHES THERE. WITH AMOUNTS ALREADY REPORTED AS HIGH AS 7
INCHES NEAR SEVEN SPRINGS...HAVE DECIDED TO MENTION ISOLATED 7 TO
10 STORM TOTAL AMOUNTS FOR THE HIGHEST ELEVATIONS...PARTICULARLY
OF WESTMORELAND AND FAYETTE COUNTIES.
TEMPS WILL ONLY INCREASE A FEW DEGREES TODAY...WITH HIGHS NEAR
LAMP GUIDANCE...RANGING FROM THE MID TEENS ACROSS THE EASTERN
RIDGES TO THE MID 20S SOUTH AND WEST OF PITTSBURGH. WITH A
TIGHTENED PRESSURE GRADIENT SETUP BETWEEN THE COASTAL LOW AND HIGH
APPROACHING FROM THE SOUTHWEST...WINDS OF 10 TO 15 MPH ARE
FORECAST WITH GUSTS TO 25 MPH FOR THE LOWLANDS AND 35 MPH FOR THE
RIDGES. THIS WILL LEAD TO WIND CHILLS BELOW 0 FOR THE RIDGES.
TONIGHT...HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST WITH AN
850MB RIDGE MOVING INTO THE AREA AND BRINGING AN END TO LINGERING
UPSLOPING SNOWS FOR THE RIDGES. SKIES WILL CLEAR OUT WITH WINDS
DECREASING TO AROUND 5 MPH. WITH 850MB TEMPS AS COLD AS
16C...ALONG WITH CLEARING AND DECREASED WINDS CONTRIBUTING TO SOME
RADIATIONAL COOLING...LOWS TONIGHT WILL RANGE FROM THE SINGLE
DIGITS ACROSS THE HIGHER ELEVATIONS TO THE MID TEENS ACROSS THE
LOWLANDS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
SOUTHERLY WINDS ON MONDAY ALONG WITH MOSTLY SUNNY SKIES WILL BRING A
MUCH WARMER DAY. COLD FRONT THAT WILL CROSS THE REGION MONDAY NIGHT
AND TUESDAY APPEARS TO BE MOVING SLIGHTLY SLOWER...AND HAVE DELAYED
FRONTAL PASSAGE BY A FEW HOURS. NO CHANGE TO CATEGORICAL POPS IN THE
FORECAST. HAVE REMOVED MENTION OF FREEZING PRECIPITATION WITH MODELS
NOT SHOWING MUCH OF A WARM TONGUE ALOFT. HOWEVER...WITH LOWS MONDAY
NIGHT EXPECTED TO BE IN THE MID 30S...TEMPERATURES WILL BE MARGINAL
FOR SNOW. A CHANGE IN THE TEMPERATURE FORECAST BY JUST A COUPLE OF
DEGREES COULD HAVE SIGNIFICANT IMPACTS TO THE PRECIPITATION TYPE
FORECAST AND POSSIBLE SNOWFALL ACCUMULATION. WITH THIS FORECAST
UPDATE...HAVE ADDED SOME LIGHT SNOW ACCUMULATIONS...GENERALLY NORTH
OF PITTSBURGH. NEARLY ALL LOCATIONS WILL SEE AT LEAST SOME RAIN ON
TUESDAY MORNING...WITH PRECIPITATION CHANGING OVER TO SNOW DURING
THE AFTERNOON HOURS BEHIND THE COLD FRONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AN ECMWF/GFS/CANADIAN BLEND INDICATES A CLOSED UPPER LEVEL VORTEX
CENTERED ACROSS THE NORTHERN GREAT LAKES WITH THE COLD FRONT
SHIFTING EAST OF THE AREA TUESDAY NIGHT. LINGERING SNOW SHOWERS ON
THE BACK SIDE OF THE FRONT WILL BE MOSTLY DIMINISHING TUESDAY
NIGHT. THE CHC OF SNOW SHOWERS WILL LINGER INTO WEDNESDAY FOR THE
HIGHER ELEVATIONS WITH UPSLOPING FAVORED BY A WESTERLY FLOW
VEERING TO WEST-NWRLY.
A GFSE/NAEFS MODEL CONSENSUS INDICATES A MID-LEVEL RIDGE AND SURFACE
HIGH SHIFTING PUSHING INTO THE UPPER OHIO VALLEY WEDNESDAY NIGHT
INTO THURSDAY WITH A DRY FORECAST IN PLACE.
A DEEP TROUGH ACROSS THE WESTERN CONUS WILL CLOSE OFF INTO A LOW
ACROSS THE NORTHERN PLAINS THURSDAY NIGHT. THE LOW WILL SWING A
FRONTAL BOUNDARY NORTHEASTWARD INTO THE UPPER OHIO VALLEY THROUGH
THE DAY FRIDAY. GFS/ECMWF ARE INDICATING THE 1000-850MB 1300M
THICKNESS LINE SLIPPING NORTHWARD ACROSS WESTERN PA ON FRIDAY. WITH
A WARMER WEDGE OF AIR ADVECTING INTO THE AREA AND CREATING A
MELTING LAYER ALOFT...THERE IS THE POTENTIAL FOR A WINTRY MIX EVENT
ACROSS THE AREA EARLY ON FRIDAY. GIVEN THAT THIS IS A DAY 6
FORECAST...THERE IS STILL QUITE A BIT OF UNCERTAINTY WITH HOW THE
THERMAL PROFILE AND AVAILABLE MOISTURE WILL SETUP WITH THIS
EVENT...SO HAVE GONE WITH A MIX OF RAIN AND SNOW AT THIS TIME.
HOWEVER...MODEL SOUNDINGS ARE HINTING AT THE POTENTIAL FOR
SLEET/FZRA AT THE ONSET OF PRECIP. THUS...THIS POTENTIAL EVENT WILL
NEED TO BE MONITORED IN THE COMING DAYS.
MODELS DIVERGE FRIDAY NIGHT INTO SATURDAY AND THUS DO NOT WAVER FAR
FROM HPC FORECAST WITH SCHC POPS FOR THE END OF THE FORECAST PERIOD.
TEMPS WILL BE AROUND 10 DEGREES BELOW NORMAL BEHIND THE FRONT ON
WEDNESDAY AND THEN MODERATE EACH DAY TO NEAR NORMAL SEASONAL VALUES
FRIDAY INTO SATURDAY.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
GENERAL MVFR FORECAST FOR REMAINDER OF MORNING WITH ISOLATED IFR AT
TIMES IN ANY HEAVIER SQUALL. SNOW SHOWERS AND SNOW BANDS WILL BEGIN
TO DIMINISH BY 17Z AND END DURING THE AFTERNOON WITH IFR RETURNING
WEST TO EAST ACROSS TERMINALS.
COASTAL LOW MOVING OFF OF NEW ENGLAND WILL TIGHTEN THE SFC PRESSURE
GRADIENT WILL PROVIDE GUSTY WINDS THIS AFTERNOON.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
HI PRES/VFR EXPD SUN NT AND MON. A CDFNT IS EXPD TO BRING
RESTRICTIONS TUE...WITH RESTRICTIONS LINGERING IN COLD NWRLY FLOW
AFT FROPA THRU WED. HI PRES/VFR EXPD FOR THU.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
WVZ023-041.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
647 AM EST SUN FEB 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST SUN FEB 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED NNW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE NRN PLAINS INTO MANITOBA. UPSTREAM ANOTHER THROUGH
AND VIGOROUS SHRTWV WAS MOVING THROUGH THE NRN ROCKIES. AT THE
SFC...A RIDGE EXTENDED FROM W OF JAMES BAY INTO UPPER MI AND WI.
WITH VERY LIGHT SYNOPTIC SCALE WINDS...LAKE INDUCED TROUGHING AND
WIND FIELDS DOMINATED LAKE SUPERIOR. LAND BREEZES ALONG WITH A WEAK
NRLY GRADIENT FLOW HAS RESULTING IN STRONGEST AREA OF LOW LEVEL CONV
OVER E CNTRL LAKE SUPERIOR FOCUSING LES INTO THE PICTURED ROCKS AND
FAR NRN SCHOOLCRAFT COUNTY. HOWEVER...SNOW INTENSITY HAS
DIMINISHED...PER RADAR REFLECTIVITY TRENDS. UPSTREAM...CLOUDS WERE
THICKENING ACROSS MN WITH WAA PATTERN AHEAD OF A TROUGH FROM SRN
SASK INTO ERN MT.
AS THE HIGH SHIFTS TO THE EAST...WINDS OVER ERN LAKE SUPERIOR WILL
FINALLY BECOME SRLY...PUSHING ANY REMAINING LES OFFSHORE. ADDITIONAL
ACCUMULATIONS AROUND AN INCH MAY BE POSSIBLE NEAR THE SHORE FROM
PICTURED ROCKS TO GRAND MARAIS. WAA WITH INCREASING SRLY WINDS AND
SUNSHINE DURING MUCH OF THE DAY WILL HELP TEMPS RECOVER QUICKLY FROM
THE FRIGID START WITH MAX READINGS CLOSER TO SEASONAL
AVERAGES...FROM AROUND 20 CNTRL TO 25 WEST.
NAM/GFS 280K-295K ISENTROPIC PROGS AND SATELLITE TRENDS SUGGEST THAT
CLOUDS WILL MOVE IN LATE TODAY AND THICKEN ACROSS THE AREA THIS
EVENING. THE STRONGEST ASCENT AND BEST CHANCE TO SATURATE THE LOWER
LEVELS IN THE VERY DRY ANTECEDENT AIRMASS WILL BE ACROSS LAKE
SUPERIOR AND THE TIP OF THE KEWEENAW. TO THE SOUTH...A LARGE PORTION
OF ANY PCPN MAY EVAPORATE BEFORE REACHING THE SFC. SO...A QPF
PATTERN MORE IN LINE WITH THE NAM WAS FAVORED. ONLY CHANCE POPS WERE
INCLUDED WITH MINIMAL IF ANY SNOW ACCUMULATIONS LESS THAN A HALF
INCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 514 AM EST SUN FEB 17 2013
ACTIVE WINTER PATTERN CONTINUES THROUGH THE UPCOMING WEEK. A COUPLE
SHOTS AT WIDESPREAD SYNOPTIC SNOWFALL...FIRST ON MONDAY/MONDAY NIGHT
THEN AGAIN ON FRIDAY. BETWEEN THESE SYSTEMS...ROBUST NNW-NW FLOW
LAKE EFFECT EVENT AFFECTS NORTHERN HALF OF UPR MICHIGAN TUESDAY INTO
WEDNESDAY. AFTER ABOVE NORMAL TEMPERATURES ON MONDAY IN SOUTHERLY
FLOW AHEAD OF LOW PRESSURE...TEMPERATURES MOST OF THE WEEK WILL BE
AT OR BLO NORMAL. COLDEST TIME APPEARS TO BE TUESDAY INTO WEDNESDAY.
TEMPERATURES REBOUND TO AROUND NORMAL TO CLOSE THE WEEK.
FIRST ISSUE IS LGT SNOW ON MONDAY AS UPR TROUGH AND DEEPENING
SFC-H85 LOWS MOVE TOWARD UPR LAKES FROM SCNTRL CANADA. WARM AIR
ADVECTION BATCH OF LGT SNOW SHOULD BE ONGOING TO START THE DAY
ACROSS LAKE SUPERIOR AND FAR NORTHERN CWA. INDICATIONS ARE THAT MOST
OF THIS SNOW WILL BE DIMINISHING THROUGH THE MORNING...LEAVING A
LULL OVER MUCH OF CWA UNTIL THE AFTN. AFT 18Z...SOUNDINGS INDICATE
DEEP MOISTENING FROM ABOVE H8 AS SFC-H85 LOWS DEEPEN WHILE MOVING
INTO WESTERN HALF OF UPR MICHIGAN. AT THIS POINT IS WHERE MODELS
DIVERGE IN HANDLING TRACK OF SFC LOW. GFS/ECMWF STAYING CONSISTENT
WITH SFC LOW MOVING INTO SOUTH CNTRL UPR MICHIGAN BY 00Z TUESDAY AND
MOVING JUST EAST OF UPR MICHIGAN BY 12Z TUESDAY. GEM-NH/UKMET SLOWER
AND FARTHER WEST WITH THE SFC LOW AS THEY SHOW IT OVER NORTHERN LK
MICHIGAN/STRAITS BY 12Z TUESDAY. ONLY A SUBTLE DIFFERENCE BUT IT IS
RESULT OF DEEPER/CLOSED OFF UPR TROUGH. A DEEPER SYSTEM WOULD RESULT
IN LGT-MODERATE SYNOPTIC SNOW OVER EAST HALF OF CWA THROUGH MOST OF
MONDAY NIGHT COMPARED TO GFS/ECMWF. MORE MOISTURE IS ALSO BROUGHT
INTO SYSTEM MONDAY AFTN/EVENING...SO ULTIMATELY SNOW AMOUNTS WOULD
BE CLOSE TO ADVY LEVELS. NOT GOING THAT WAY NOW...THOUGH WILL ADMIT
THE GEM-NH CONSISTENCY IS A BIT CONCERNING. EVEN SO...PRIMARY
WEST-EAST JET ENERGY STAYS LOCKED INTO SOUTHERN STREAM OF THE UPPER
TROUGH WHICH SUPPORTS GOING WITH MORE PROGRESSIVE UPR TROUGH AND A
FARTHER EAST SFC LOW TRACK. UPSHOT...A FEW INCHES OF SNOW IN THE
EAST WITH JUST AN INCH OR TWO ELSEWHERE OVR CWA. SNOW WILL BE A
WETTER TYPE SNOW...NOT THE REALLY FLUFFY VARIETY THAT HAS BEEN WITH
US LATELY.
DEEPENING UPPER TROUGH SWINGS ACROSS GREAT LAKES ON TUESDAY HELPING
TO DRAW IN MUCH COLDER AIR YET AGAIN. H85 TEMPS AT 06Z TUESDAY ONLY
AS COLD AS AROUND -13C OVR LK SUPERIOR BUT BY 18Z TUESDAY ARE
ALREADY DOWN BLO -20C. ALL THE WHILE...SINCE UPR TROUGH IS DEEPENING
OVR THE AREA...THERE IS PLENTY OF DEEPER MOISTURE PRESENT WITH
STRONG CYCLONIC N-NW FLOW. KIND OF A PSUEDO LAKE ENHANCED SETUP
THOUGH THERE DOES NOT LOOK TO BE MUCH LARGE SCALE LIFT GOING ON.
SLR/S IN THEORY SHOULD END UP OVR 30:1 BUT GIVEN STRONG WINDS OVR 30
KTS IN THE BLYR...EXPECT FRACTURING TO HOLD SLR/S DOWN TO AN AVERAGE
OF 25-30:1. FIRST PASS AT SNOW AMOUNTS INDICATES HIGH-END ADVY BUT
SIMILAR TO LAST EVENT...LONG DURATION OF THE SNOW MAY RESULT IN SNOW
TOTALS FROM LATE MONDAY NIGHT THROUGH TUESDAY NIGHT AND WEDNESDAY
OVER A FOOT IN SOME LOCATIONS. FAVORED LOCATIONS WITH EXPECTED NNW
WINDS WOULD BE MUCH OF HIGHER TERRAIN OF ONTONAGON COUNTY THROUGH
TWIN LAKES...HIGHER TERRAIN OF BARAGA AND NORTHERN MARQUETTE
COUNTY...THEN EVENTUALLY THE SNOWBELTS OVER OF THE EASTERN CWA LATER
TUESDAY THROUGH WEDNESDAY. UNLIKE RECENT LAKE SNOW EVENT...WIND/BLSN
WILL BE BIGGER ISSUE WITH WELL MIXED BLYR. EXPECT WIDESPREAD BLSN
AND REDUCED VSBY ALONG WITH MODERATE TO HEAVY SNOW SHOWERS.
SINCE WE STILL HAVE TO GET THROUGH THE WIDESPREAD SYNOPTIC LGT SNOW
MONDAY AND MONDAY EVENING AND THIS IS MAINLY A 5TH PERIOD AND BEYOND
EVENT DID NOT ISSUE ANY HEADLINES AT THIS POINT. WILL MENTION IN HWO
AND HIT UP THE BLSN AS WELL. SEEMS THAT TRAVEL MAY BE DIFFICULT NEAR
MUCH OF LK SUPERIOR TUESDAY INTO TUESDAY EVENING.
REST OF LONG TERM...LK EFFECT DIMINISHES STEADILY ON WEDNESDAY FROM
WEST TO EAST AS UPR TROUGH/DEEPER MOISTURE EXITS TO EAST. LEFT OVER
LAKE EFFECT WILL BE PLAGUED BY LOWERING INVERSION AND DIMINISHING
CYCLONIC FLOW. WEAKER LK EFFECT AND/OR FLURRIES HANG ON THROUGH
THURSDAY OVER NCNTRL CWA WITH WINDS BECOMING N/NE. DRY ELSEWHERE AS
WE AWAIT SYSTEM THAT WILL BE BRINGING SNOW TO PARTS OF NORTHERN
PLAINS AND MO RIVER VALLEY ON THURSDAY. GFS/ECMWF IN VERY GOOD
AGREEMENT THAT SFC LOW LIFTS TOWARD UPR MISSISSIPPI RIVER VALLEY BY
DAYBREAK FRIDAY AND WEAKENS WHILE MOVING INTO UPR LAKES LATE FRIDAY.
SWATH OF LGT SNOW COMES IN FROM SOUTHWEST LATE THURSDAY NIGHT AND A
GENERAL DECAYING TREND TO SNOW CONTINUES ON FRIDAY...THOUGH AT LEAST
LGT ACCUMS WILL AFFECT MUCH OF UPR MICHIGAN ON FRIDAY. POPS HIGH
CHANCE FOR NOW BUT IF MODELS REMAIN IN GOOD AGREEMENT COULD
EVENTUALLY SEE NEED FOR LIKELY POPS THU NIGHT INTO FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 645 AM EST SUN FEB 17 2013
EXPECT VFR CONDITIONS EARLY TODAY WITH HIGH PRES AND DRY AIR DOMINATING.
THE EXCEPTION WILL BE AT CMX...WHERE ONSHORE/UPSLOPE HAS WILL KEEP
SOME LAKE CLOUDS/MVFR CIGS FOR THE FIRST COUPLE HOURS OF THE TAF
PERIOD. TODAY WILL FEATURE RATHER TRANQUIL VFR WX WITH THE HIGH
DRIFTING TO THE E AND SOME INCREASING HIGH CLOUDS E OF A TROUGH
MOVING THROUGH THE NRN PLAINS. A GUSTY S WIND WILL DEVELOP AT IWD IN
THE AFTERNOON AND CONTINUE THROUGH THE EVENING AS THE PRES GRADIENT
TIGHTENS. ALTHOUGH THE CLOUDS WILL THICKEN TONIGHT...SLY FLOW OF DRY
LLVL AIR AS WELL AS DOWNSLOPE NATURE OF THE FLOW AT IWD/CMX WILL
FAVOR VFR CIGS THROUGH THE EVENING. ENOUGH LOW LEVEL MOISTURE WITH
UPSLOPE FLOW INTO CENTRAL UPPER MI IS EXPECTED TO LEAD TO MVFR CIGS
AT SAW OVERNIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST SUN FEB 17 2013
AS HIGH PRES SHIFTS TO THE EAST...A LOW PRESSURE SYSTEM WILL
APPROACH THE UPPER GREAT LAKES ON MONDAY AND MOVE THROUGH ON
TUESDAY. THIS WILL BRING INCREASING SOUTHERLY WINDS ON MONDAY...TO
30 KTS OVER THE EAST...AND THEN STRONG NORTHERLY GALES BEHIND THE
LOW ON TUESDAY AND TUESDAY NIGHT...TO 45 KTS. THERE COULD BE A FEW
GALE FORCE GUSTS TO 35 KNOTS ON MONDAY OVER EASTERN LAKE SUPERIOR.
WITH THE HIGHER WINDS AND COLDER AIR TUESDAY INTO WEDNESDAY...HEAVY
FREEZING SPRAY IS ALSO EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ006-
085.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR
LSZ245>251-265>267.
GALE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR
LSZ162.
GALE WATCH FROM LATE MONDAY NIGHT THROUGH WEDNESDAY AFTERNOON
FOR LSZ240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
517 AM EST SUN FEB 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST SUN FEB 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED NNW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE NRN PLAINS INTO MANITOBA. UPSTREAM ANOTHER THROUGH
AND VIGOROUS SHRTWV WAS MOVING THROUGH THE NRN ROCKIES. AT THE
SFC...A RIDGE EXTENDED FROM W OF JAMES BAY INTO UPPER MI AND WI.
WITH VERY LIGHT SYNOPTIC SCALE WINDS...LAKE INDUCED TROUGHING AND
WIND FIELDS DOMINATED LAKE SUPERIOR. LAND BREEZES ALONG WITH A WEAK
NRLY GRADIENT FLOW HAS RESULTING IN STRONGEST AREA OF LOW LEVEL CONV
OVER E CNTRL LAKE SUPERIOR FOCUSING LES INTO THE PICTURED ROCKS AND
FAR NRN SCHOOLCRAFT COUNTY. HOWEVER...SNOW INTENSITY HAS
DIMINISHED...PER RADAR REFLECTIVITY TRENDS. UPSTREAM...CLOUDS WERE
THICKENING ACROSS MN WITH WAA PATTERN AHEAD OF A TROUGH FROM SRN
SASK INTO ERN MT.
AS THE HIGH SHIFTS TO THE EAST...WINDS OVER ERN LAKE SUPERIOR WILL
FINALLY BECOME SRLY...PUSHING ANY REMAINING LES OFFSHORE. ADDITIONAL
ACCUMULATIONS AROUND AN INCH MAY BE POSSIBLE NEAR THE SHORE FROM
PICTURED ROCKS TO GRAND MARAIS. WAA WITH INCREASING SRLY WINDS AND
SUNSHINE DURING MUCH OF THE DAY WILL HELP TEMPS RECOVER QUICKLY FROM
THE FRIGID START WITH MAX READINGS CLOSER TO SEASONAL
AVERAGES...FROM AROUND 20 CNTRL TO 25 WEST.
NAM/GFS 280K-295K ISENTROPIC PROGS AND SATELLITE TRENDS SUGGEST THAT
CLOUDS WILL MOVE IN LATE TODAY AND THICKEN ACROSS THE AREA THIS
EVENING. THE STRONGEST ASCENT AND BEST CHANCE TO SATURATE THE LOWER
LEVELS IN THE VERY DRY ANTECEDENT AIRMASS WILL BE ACROSS LAKE
SUPERIOR AND THE TIP OF THE KEWEENAW. TO THE SOUTH...A LARGE PORTION
OF ANY PCPN MAY EVAPORATE BEFORE REACHING THE SFC. SO...A QPF
PATTERN MORE IN LINE WITH THE NAM WAS FAVORED. ONLY CHANCE POPS WERE
INCLUDED WITH MINIMAL IF ANY SNOW ACCUMULATIONS LESS THAN A HALF
INCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 514 AM EST SUN FEB 17 2013
ACTIVE WINTER PATTERN CONTINUES THROUGH THE UPCOMING WEEK. A COUPLE
SHOTS AT WIDESPREAD SYNOPTIC SNOWFALL...FIRST ON MONDAY/MONDAY NIGHT
THEN AGAIN ON FRIDAY. BETWEEN THESE SYSTEMS...ROBUST NNW-NW FLOW
LAKE EFFECT EVENT AFFECTS NORTHERN HALF OF UPR MICHIGAN TUESDAY INTO
WEDNESDAY. AFTER ABOVE NORMAL TEMPERATURES ON MONDAY IN SOUTHERLY
FLOW AHEAD OF LOW PRESSURE...TEMPERATURES MOST OF THE WEEK WILL BE
AT OR BLO NORMAL. COLDEST TIME APPEARS TO BE TUESDAY INTO WEDNESDAY.
TEMPERATURES REBOUND TO AROUND NORMAL TO CLOSE THE WEEK.
FIRST ISSUE IS LGT SNOW ON MONDAY AS UPR TROUGH AND DEEPENING
SFC-H85 LOWS MOVE TOWARD UPR LAKES FROM SCNTRL CANADA. WARM AIR
ADVECTION BATCH OF LGT SNOW SHOULD BE ONGOING TO START THE DAY
ACROSS LAKE SUPERIOR AND FAR NORTHERN CWA. INDICATIONS ARE THAT MOST
OF THIS SNOW WILL BE DIMINISHING THROUGH THE MORNING...LEAVING A
LULL OVER MUCH OF CWA UNTIL THE AFTN. AFT 18Z...SOUNDINGS INDICATE
DEEP MOISTENING FROM ABOVE H8 AS SFC-H85 LOWS DEEPEN WHILE MOVING
INTO WESTERN HALF OF UPR MICHIGAN. AT THIS POINT IS WHERE MODELS
DIVERGE IN HANDLING TRACK OF SFC LOW. GFS/ECMWF STAYING CONSISTENT
WITH SFC LOW MOVING INTO SOUTH CNTRL UPR MICHIGAN BY 00Z TUESDAY AND
MOVING JUST EAST OF UPR MICHIGAN BY 12Z TUESDAY. GEM-NH/UKMET SLOWER
AND FARTHER WEST WITH THE SFC LOW AS THEY SHOW IT OVER NORTHERN LK
MICHIGAN/STRAITS BY 12Z TUESDAY. ONLY A SUBTLE DIFFERENCE BUT IT IS
RESULT OF DEEPER/CLOSED OFF UPR TROUGH. A DEEPER SYSTEM WOULD RESULT
IN LGT-MODERATE SYNOPTIC SNOW OVER EAST HALF OF CWA THROUGH MOST OF
MONDAY NIGHT COMPARED TO GFS/ECMWF. MORE MOISTURE IS ALSO BROUGHT
INTO SYSTEM MONDAY AFTN/EVENING...SO ULTIMATELY SNOW AMOUNTS WOULD
BE CLOSE TO ADVY LEVELS. NOT GOING THAT WAY NOW...THOUGH WILL ADMIT
THE GEM-NH CONSISTENCY IS A BIT CONCERNING. EVEN SO...PRIMARY
WEST-EAST JET ENERGY STAYS LOCKED INTO SOUTHERN STREAM OF THE UPPER
TROUGH WHICH SUPPORTS GOING WITH MORE PROGRESSIVE UPR TROUGH AND A
FARTHER EAST SFC LOW TRACK. UPSHOT...A FEW INCHES OF SNOW IN THE
EAST WITH JUST AN INCH OR TWO ELSEWHERE OVR CWA. SNOW WILL BE A
WETTER TYPE SNOW...NOT THE REALLY FLUFFY VARIETY THAT HAS BEEN WITH
US LATELY.
DEEPENING UPPER TROUGH SWINGS ACROSS GREAT LAKES ON TUESDAY HELPING
TO DRAW IN MUCH COLDER AIR YET AGAIN. H85 TEMPS AT 06Z TUESDAY ONLY
AS COLD AS AROUND -13C OVR LK SUPERIOR BUT BY 18Z TUESDAY ARE
ALREADY DOWN BLO -20C. ALL THE WHILE...SINCE UPR TROUGH IS DEEPENING
OVR THE AREA...THERE IS PLENTY OF DEEPER MOISTURE PRESENT WITH
STRONG CYCLONIC N-NW FLOW. KIND OF A PSUEDO LAKE ENHANCED SETUP
THOUGH THERE DOES NOT LOOK TO BE MUCH LARGE SCALE LIFT GOING ON.
SLR/S IN THEORY SHOULD END UP OVR 30:1 BUT GIVEN STRONG WINDS OVR 30
KTS IN THE BLYR...EXPECT FRACTURING TO HOLD SLR/S DOWN TO AN AVERAGE
OF 25-30:1. FIRST PASS AT SNOW AMOUNTS INDICATES HIGH-END ADVY BUT
SIMILAR TO LAST EVENT...LONG DURATION OF THE SNOW MAY RESULT IN SNOW
TOTALS FROM LATE MONDAY NIGHT THROUGH TUESDAY NIGHT AND WEDNESDAY
OVER A FOOT IN SOME LOCATIONS. FAVORED LOCATIONS WITH EXPECTED NNW
WINDS WOULD BE MUCH OF HIGHER TERRAIN OF ONTONAGON COUNTY THROUGH
TWIN LAKES...HIGHER TERRAIN OF BARAGA AND NORTHERN MARQUETTE
COUNTY...THEN EVENTUALLY THE SNOWBELTS OVER OF THE EASTERN CWA LATER
TUESDAY THROUGH WEDNESDAY. UNLIKE RECENT LAKE SNOW EVENT...WIND/BLSN
WILL BE BIGGER ISSUE WITH WELL MIXED BLYR. EXPECT WIDESPREAD BLSN
AND REDUCED VSBY ALONG WITH MODERATE TO HEAVY SNOW SHOWERS.
SINCE WE STILL HAVE TO GET THROUGH THE WIDESPREAD SYNOPTIC LGT SNOW
MONDAY AND MONDAY EVENING AND THIS IS MAINLY A 5TH PERIOD AND BEYOND
EVENT DID NOT ISSUE ANY HEADLINES AT THIS POINT. WILL MENTION IN HWO
AND HIT UP THE BLSN AS WELL. SEEMS THAT TRAVEL MAY BE DIFFICULT NEAR
MUCH OF LK SUPERIOR TUESDAY INTO TUESDAY EVENING.
REST OF LONG TERM...LK EFFECT DIMINISHES STEADILY ON WEDNESDAY FROM
WEST TO EAST AS UPR TROUGH/DEEPER MOISTURE EXITS TO EAST. LEFT OVER
LAKE EFFECT WILL BE PLAGUED BY LOWERING INVERSION AND DIMINISHING
CYCLONIC FLOW. WEAKER LK EFFECT AND/OR FLURRIES HANG ON THROUGH
THURSDAY OVER NCNTRL CWA WITH WINDS BECOMING N/NE. DRY ELSEWHERE AS
WE AWAIT SYSTEM THAT WILL BE BRINGING SNOW TO PARTS OF NORTHERN
PLAINS AND MO RIVER VALLEY ON THURSDAY. GFS/ECMWF IN VERY GOOD
AGREEMENT THAT SFC LOW LIFTS TOWARD UPR MISSISSIPPI RIVER VALLEY BY
DAYBREAK FRIDAY AND WEAKENS WHILE MOVING INTO UPR LAKES LATE FRIDAY.
SWATH OF LGT SNOW COMES IN FROM SOUTHWEST LATE THURSDAY NIGHT AND A
GENERAL DECAYING TREND TO SNOW CONTINUES ON FRIDAY...THOUGH AT LEAST
LGT ACCUMS WILL AFFECT MUCH OF UPR MICHIGAN ON FRIDAY. POPS HIGH
CHANCE FOR NOW BUT IF MODELS REMAIN IN GOOD AGREEMENT COULD
EVENTUALLY SEE NEED FOR LIKELY POPS THU NIGHT INTO FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 622 PM EST SAT FEB 16 2013
THE ARRIVAL OF LARGER SCALE SUBSIDENCE/SFC HI PRES RDG WL CAUSE
LINGERING LES AT CMX/IWD TO DIMINISH THIS EVNG. WITH BACKING LLVL
FLOW TO W AND THEN S...EXPECT SKIES TO CLR AT IWD...WITH VFR
CONDITIONS SOON AFTER FCST ISSUANCE. WITH A W ONSHORE/UPSLOPE
FLOW...MVFR CIGS/SOME -SHSN OR FLURRIES WL LINGER MUCH OF THE NGT AT
CMX UNTIL WINDS BACK SUFFICIENTLY LATER TO PUSH LK CLDS TO THE N OF
THIS SITE AND VFR WX TAKES HOLD. EXPECT EXPERIENCE VFR CONDITIONS AT
SAW WITH DOWNSLOPING ACYC FLOW. SUN WL FEATURE RATHER TRANQUIL VFR
WX WITH INCRSG HI CLDS E OF LO PRES TROF MOVING THRU THE NRN PLAINS.
A GUSTY S WIND WL DVLP AT IWD IN THE AFTN AS PRES GRADIENT TIGHTENS
AHEAD OF THIS FEATURE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST SUN FEB 17 2013
AS HIGH PRES SHIFTS TO THE EAST...A LOW PRESSURE SYSTEM WILL
APPROACH THE UPPER GREAT LAKES ON MONDAY AND MOVE THROUGH ON
TUESDAY. THIS WILL BRING INCREASING SOUTHERLY WINDS ON MONDAY...TO
30 KTS OVER THE EAST...AND THEN STRONG NORTHERLY GALES BEHIND THE
LOW ON TUESDAY AND TUESDAY NIGHT...TO 45 KTS. THERE COULD BE A FEW
GALE FORCE GUSTS TO 35 KNOTS ON MONDAY OVER EASTERN LAKE SUPERIOR.
WITH THE HIGHER WINDS AND COLDER AIR TUESDAY INTO WEDNESDAY...HEAVY
FREEZING SPRAY IS ALSO EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ006-
085.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR
LSZ245>251-265>267.
GALE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR
LSZ162.
GALE WATCH FROM LATE MONDAY NIGHT THROUGH WEDNESDAY AFTERNOON
FOR LSZ240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
558 AM CST SUN FEB 17 2013
.SHORT TERM...
ISSUED AT 311 AM CST SUN FEB 17 2013
(TODAY)
WINDS WILL BECOME SELY TODAY AS A SFC RIDGE AXIS SHIFTS EAST OF THE
AREA. TEMPERATURES ALOFT WILL RISE DURING THE DAY AS THE UPPER LEVEL
RIDGE ALSO SHIFTS EWD. ALTHOUGH NO MODEL IS HANDLING THE PATCH OF
WAA CLOUDS OVERHEAD VERY WELL...RAP FCSTS OF CONDENSATION PRESSURE
DEFICITS BETWEEN 875-800MB DO SUGGEST SOME THINNING WILL OCCUR BY
18Z AS THE THICKER CLOUDS SHIFT SOUTHEAST OF THE CWA. GIVEN THESE
EXPECTED CLOUD TRENDS AND A SLY WIND COMPONENT...AFTN HIGHS IN THE
MID 40S TO MID 50S LOOK REASONABLE BASED ON 21Z T85 FCSTS OF -4 TO 0
DEG C WITH AFTN MIXING TO BETWEEN H9-H85.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 311 AM CST SUN FEB 17 2013
THE UPCOMING WEEK WILL BE DOMINATED BY TWO STORM SYSTEMS...ONE ON
MONDAY AND THE OTHER PRIMARILY FOR THURSDAY.
(TONIGHT - MONDAY NIGHT)
A STRONG SHORTWAVE OVER THE PAC NW ATTM WILL RAPIDLY TRANSLATE E IN
A LONGWAVE FLOW THAT IS TRANSITIONAL...AS ONE LONGWAVE TROF EXITS
OFF THE ERN CONUS AND ANOTHER IS EXPECTED TO MOVE INTO THE WRN CONUS
BY MID-WEEK. STRONG LO LEVEL JET OF 65KTS EXPECTED TO DEVELOP THIS
EVENING WILL HELP FUNNEL GULF OF MEXICO MOISTURE INTO THE MID MS
VALLEY ON MONDAY JUST AS THE DEEPER LIFT FROM THE SHORTWAVE
APPROACH. THE RESULT SHOULD BE RAPIDLY DEVELOPING PCPN ON MONDAY
THRU EARLY AFTERNOON WITH THE PCPN THEN SHOVING OFF TO THE E DURING
THE EVENING. VERTICAL TEMP PROFILES TOO WARM FOR ANYTHING BUT
LIQUID PCPN FOR THE EVENT...BUT FCST SOUNDINGS DO INDICATE
SUFFICIENT INSTABILITY TO SUPPORT SOME THUNDER THAT IS ELEVATED IN
NATURE...ALTHOUGH WITH SKINNY CAPES INDICATED...SHOULD SEE SHRA WITH
EMBEDDED TSRA AND THIS IS WELL HANDLED BY PREVIOUS FCST ALREADY AND
SO LET RIDE. SFC-BASED CONVECTION SEEMS REMOTE WITH DWPTS NOT
EXPECTED TO EXCEED 50F.
LIKELY-CATEGORICAL POPS STILL LOOK GOOD...WITH THE HIGHEST POPS FOR
STL METRO AND S AND E DURING MONDAY AFTERNOON.
THE STRONG LO LEVEL JET WILL ALSO CREATE ANOTHER PROBLEM...NAMELY
THE POTENTIAL TO MIX DOWN TO THE SFC. MODELS INDICATE SPEEDS OF
60KTS AS LO AS JUST 2KFT OFF THE SFC AND MIXING HEIGHTS...WHILE
LO...WILL HAVE THE ABILITY TO TAP GUSTS APPROACHING ADVISORY
CRITERIA OF 45MPH...ESPECIALLY IN AREAS TO THE S AND E OF STL
METRO. HAVE BUMPED UP GUSTS TO 40MPH IN THESE AREAS FOR NOW.
TEMPS WILL DO MUCH...IF NOT ALL...OF THEIR DROP THIS EVENING BEFORE
STRONGER S FLOW KICKS IN AND CLOUDS THICKEN. AT THAT POINT...LOOK
FOR STEADY OR SLOWLY RISING OVERNIGHT. MONDAY MOS TEMPS LOOK TOO
WARM IN SPOTS...NAMELY FOR STL METRO...BUT OTHERWISE LO-MID 50S
FOR MOST LOCALES LOOKS GOOD.
(TUESDAY - WEDNESDAY)
A COLD AIRMASS WILL TAKE HOLD DURING THIS PERIOD...WITH IT JUST
STARTING TO GET ESTABLISHED ON TUESDAY AND IT SHOULD BE WELL
ENTRENCHED INTO THE AREA ON WEDNESDAY. FAVORED WARMER END OF MOS ON
TUESDAY WITH GOOD SUNSHINE EXPECTED AND DEEP MIXING...MOS SEEMS TO
BE CONSISTENTLY TOO COOL IN THESE SITUATIONS. WEDNESDAY EXPECTED TO
BE COLDER WITH COLDER EARLY MORNING START...NE-E FLOW...AND
INCREASING CLOUDS.
(THURSDAY - SATURDAY)
WITH LONGWAVE TROF ANTICIPATED TO REFORM OVER THE WRN CONUS...WE
WILL BEGIN TO SEE STORMS APPROACH FROM THE SW AGAIN AND THE THURSDAY
STORM WILL BE THE FIRST IN THAT SERIES.
AN INITIAL IMPULSE...WHICH IS COMMON IN THESE TYPES OF STORMS...WILL
SHOOT OUT AHEAD OF THE MAIN STORM AND PERHAPS AFFECT THE AREA LATE
WEDNESDAY NIGHT WITH THE MAIN EVENT STILL ON TRACK FOR THURSDAY AND
PERHAPS A PERIOD OF DRIZZLE THURSDAY NIGHT AS THE OCCLUDED FRONT
MOVES THRU IN REGION OF CYCLONIC LO LEVEL FLOW AND SLOWLY RETREATING
LO CLOUD.
VERY FEW CHANGES MADE TO CURRENT FCST WITH RESPECT TO PCPN-TYPES AND
TIMING AS IT STILL LOOKS ON TARGET WITH THE DATA WE HAVE. OCCLUDED
SYSTEM CENTER TO PASS TO OUR NW...BUT THAT IS THE KEY...OCCLUDED
SYSTEM...WITH COLD AIR AT THE LO LEVELS TO REMAIN IN PLACE ACROSS
THE FA...THE MAIN WARM SECTOR STAYING TO THE S. AS IT STANDS
NOW...WAA EVENT WILL FEATURE A WINTRY MIX ACROSS THE FA... WITH
MAINLY SNOW AND SLEET IN NERN MO AND W-CNTRL IL...FZRA/RA FOR AREAS
FURTHER S...DEPENDING ON EXACTLY WHERE THE 32F LINE IS AT THE SFC.
AND THAT IS ANOTHER THING TO KEEP IN MIND...SKILL AT FCSTG 32F LINE
SIMPLY NOT SUFFICIENT AT THIS TIME TO SAY WHO WILL RECEIVE A HIGH
IMPACT EVENT AND WHO WILL NOT. BUT BASED ON OUR CURRENT
DETERMINISTIC FCST...COULD SEE FAIRLY SIZABLE SNOW AND ICE ACCUMS BY
THE TIME IT IS ALL SAID AND DONE...WITH THE BEST PROBS FOR THIS WILL
BE ALG-N OF I-70. PERIODS OF FZDZ-DZ THEN LOOKS TO BE A GOOD BET
FOR THURS NGT.
BELOW AVERAGE TEMPS THEN EXPECTED FOR FRIDAY AND SATURDAY. SEVERAL
ADDITIONAL DISTURBANCES WILL PUSH THRU IN THE WAKE OF THE THURSDAY
STORM...BUT MOISTURE WILL BE LIMITED...UNLESS A SYSTEM CAN GENERATE
ENOUGH LIFT. ONLY PLACED IN SLIGHT CHC POPS FOR SATURDAY.
TES
&&
.AVIATION...
ISSUED AT 537 AM CST SUN FEB 17 2013
THE 6-8 KFT CLOUD DECK THAT WAS LOCATED OVER THE TERMINALS AT TAF
ISSUANCE IS EXPECTED TO SHIFT SEWD AND THIN OUT OVER THE NEXT
SEVERAL HOURS BASED ON RAP FCSTS OF CONDENSATION PRESSURE
DEFICITS. SFC WINDS WILL BECOME SELY TODAY THEN INCREASE TONIGHT
ONCE THE PRESSURE GRADIENT TIGHTENS AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM. A LOW LEVEL JET WILL ALSO DEVELOP TONIGHT AND
PRODUCE LLWS CONDITIONS FROM LATE TONIGHT THROUGH EARLY TOMORROW
MORNING. BEYOND THE END OF THE 24 HR TAF PD...RAIN SHOWERS ARE
EXPECTED TO SPREAD ACROSS THE REGION WITH CIG/VIS RESTRICTIONS
LIKELY.
SPECIFICS FOR KSTL...VFR CONDITIONS ARE EXPECTED FOR AT LEAST THE
FIRST 12-18 HOURS OF THE TAF PD. THE 6-8 KFT CLOUD DECK THAT WAS
LOCATED OVER KSTL AT TAF ISSUANCE IS EXPECTED TO SHIFT SEWD AND
THIN OUT OVER THE NEXT SEVERAL HOURS. SFC WINDS BECOME SELY TODAY
THEN INCREASE TONIGHT ONCE THE PRESSURE GRADIENT TIGHTENS AHEAD OF
AN APPROACHING LOW PRESSURE SYSTEM. A LOW LEVEL JET WILL DEVELOP
TONIGHT AND PRODUCE LLWS CONDITIONS FROM LATE TONIGHT THROUGH
EARLY TOMORROW MORNING. RAIN SHOWERS WITH CIG/VIS RESTRICTIONS ARE
EXPECTED TOMORROW MORNING AT KSTL.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
626 AM EST SUN FEB 17 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE WILL BUILD TOWARD THE CAROLINAS FROM THE
SOUTHWEST TODAY AS A RAPIDLY INTENSIFYING LOW PRESSURE SYSTEM
OFFSHORE THE MID ATLANTIC COAST TRACKS NORTHEAST TOWARD THE CANADIAN
MARITIMES. HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT BEFORE
MOVING OFFSHORE LATE MONDAY INTO MONDAY NIGHT AS A COLD FRONT
APPROACHES THE MOUNTAINS FROM THE WEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM SUNDAY...
THIS MORNING:
A LINGERING NNW-SSE ORIENTED BAND OF SNOW OVER THE COASTAL PLAIN
WILL CONTINUE TO WEAKEN...DISSIPATING BY 300-330 AM AS THE UPPER
LEVEL TROUGH AXIS PROGRESSES EAST OF CENTRAL NC AND STRENGTHENING
SYNOPTIC SUBSIDENCE RESULTS IN RAPID DRYING ALOFT. AS MUCH AS 1.0 TO
1.5 INCHES OF SNOW ACCUMULATION OCCURRED IN ASSOCIATION WITH THIS
BAND OVER GRANVILLE...VANCE...FRANKLIN...EASTERN WAKE... JOHNSTON...
WAYNE AND EASTERN SAMPSON COUNTIES BETWEEN 900 PM SATURDAY EVENING
AND 200 AM THIS MORNING. EXPECT DANGEROUS ROAD CONDITIONS ALONG THE
INTERSTATE 85 CORRIDOR FROM DURHAM NORTH TO THE VIRGINIA
BORDER...ALONG THE INTERSTATE 40 CORRIDOR FROM RALEIGH EAST TO
BENSON-HOBBTON-WARSAW...AND ALONG THE INTERSTATE 95 CORRIDOR FROM
BENSON NORTH TO ROANOKE RAPIDS. HAVE HIGHLIGHTED THESE AREAS IN THE
WINTER WEATHER ADVISORY THAT REMAINS IN EFFECT UNTIL 10 AM THIS
MORNING...WHEN TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING.
ADDITIONAL SHORTWAVE ENERGY APPROACHING WEST VIRGINIA AT 07Z IS
PROGGED TO TRACK SOUTHEAST THROUGH SOUTHERN VA AND NORTHEAST NC
BETWEEN 12-15Z THIS MORNING...IN THE PRESENCE OF LINGERING LOW-LEVEL
MOISTURE AND STEEP MID-LEVEL LAPSE RATES (7-7.5 C/KM) OVER THE N/NE
OF THE TRIANGLE INTO CENTRAL/SOUTHEAST VA (PER 00Z RAOB AND THE
LATEST RAP MODEL DATA). IT IS POSSIBLE THAT FLURRIES MAY OCCUR N AND
NE OF THE TRIANGLE TOWARD THE VA BORDER (ROXBORO EAST TO ROANOKE
RAPIDS) BETWEEN 09-15Z WHERE DPVA IN THE PRESENCE OF STEEP MID-LEVEL
LAPSE RATES AND LINGERING LOW-LEVEL MOISTURE IN THE ICE NUCLEATION
ZONE MAY (BARELY) OVERCOME STRENGTHENING SUBSIDENCE ALOFT...THOUGH
NO MEASURABLE PRECIPITATION WOULD BE EXPECTED. 07Z RADAR DATA FROM
KFCX LENDS CREDENCE TO THIS POSSIBILITY.
THIS AFTERNOON THROUGH TONIGHT:
PRONOUNCED DRYING ALOFT (ESPECIALLY 8+ KFT AGL) WILL OCCUR
THROUGHOUT THE DAY AS THE UPPER LEVEL TROUGH AXIS PROGRESSES
OFFSHORE THE MID-ATLANTIC AND CAROLINA COAST. LOW-LEVEL MOISTURE
PROGGED TO ADVECT INTO THE REGION FROM THE NW UNDERNEATH THE
STRENGTHENING MID-LEVEL SUBSIDENCE INVERSION MAY ALLOW FOR SCATTERED
CLOUD COVER WITH BASES AT 5-7 KFT AGL TODAY. OTHERWISE...EXPECT
MOSTLY SUNNY SKIES. 1000-850 MB THICKNESSES AND H85 TEMPS SUGGEST
CHILLY TEMPS TODAY...RANGING FROM THE MID 30S N/NE TO UPPER 30S AND
LOWER 40S FAR S/SW. 25-35 KT FLOW NW FLOW IN THE MIXED LAYER
(STRONGEST THROUGH 18Z) WILL RESULT IN BREEZY CONDITIONS...
ESPECIALLY N/NE OF THE TRIANGLE. EXPECT SUSTAINED NW WINDS AT 10-20
MPH WITH GUSTS GENERALLY IN THE 20-30 MPH RANGE...THOUGH SPORADIC
HIGHER GUSTS UP TO 35 MPH WILL BE POSSIBLE. EXPECT WIND CHILL VALUES
IN THE TEENS (PRIMARILY NORTH OF HWY 64) THIS MORNING...AND
LINGERING IN THE 20S THIS AFTERNOON...ESPECIALLY IN THE NORTH. WITH
A COLD/DRY AIRMASS IN PLACE...CLEAR SKIES AND AND CALM WINDS TONIGHT
AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION FROM THE
SOUTHWEST... EXPECT EXCELLENT RADIATIONAL COOLING WITH CHILLY LOWS
RANGING FROM THE MID/UPPER TEENS IN RURAL/LOW-LYING AREAS TO LOWER
20S IN URBAN AREAS. -VINCENT
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...
AS THE COLD MODIFIED ARCTIC SURFACE HIGH SLIPS EAST AND OFFSHORE
MONDAY... THE RETURN FLOW WILL BRING A STRONG WARMING TREND BY
AFTERNOON. HOWEVER... THE AIR MASS WILL REMAIN DRY AND WITH THE
BREEZY WINDS (EVEN IF THEY ARE FROM THE SW) IT WILL STILL FEEL
RATHER CHILLY. HIGHS 50-55 EXPECTED WITH MOSTLY SUNNY SKIES.
INCREASING MID AND HIGH LEVEL MOISTURE WILL LEAD TO PARTLY CLOUDY
BECOMING MOSTLY CLOUDY SKIES MONDAY NIGHT. LOWS WILL BE MUCH MILDER
WITH LOWS IN THE UPPER 30S TO MID 40S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 317 AM SUNDAY...
THE MAIN STORM TRACK WITH THE NEXT APPROACHING SYSTEM IS EXPECTED TO
BE FROM THE MIDWEST NE ACROSS THE GREAT LAKES TUE-TUE NIGHT. THE
TRAILING COLD FRONT IS EXPECTED TO PUSH EAST ACROSS OUR REGION
TUESDAY. INITIALLY... A STRONG AND MOIST FLOW FROM THE GULF WILL
ALLOW FOR SIGNIFICANT RAIN INTO THE TENNESSEE VALLEY INTO FAR
WESTERN NC INTO MONDAY NIGHT. HOWEVER... AS THE STORM MOVES OVER THE
GREAT LAKES... THE MEAN FLOW IS EXPECTED TO BECOME PROGRESSIVELY
MORE WESTERLY AS THE SYSTEM MOVES ACROSS THE APPALACHIANS TO THE
MID-ATLANTIC COAST TUESDAY AFTERNOON AND EVENING. THIS EFFECTIVELY
SHUTS DOWN THE GULF INFLOW AS THE COLD FRONT MOVES THROUGH CENTRAL
NC. WE WILL CONTINUE TO CARRY HIGH POPS BUT LOW QPF. MOST AREAS
SHOULD SEE LESS THAN 0.25 WITH EASTERN ZONES POSSIBLY LESS THAN
0.10. THE LIKELY POP WILL BE CONFINED TO TUESDAY... WITH RAPIDLY
DECREASING POP TUESDAY EVENING FROM WEST TO EAST AS THE COLD FRONT
REACHES THE COAST. HIGHS TUESDAY WILL BE HELD DOWN DUE TO THE CLOUDS
AND SHOWERS. EXPECT SOME 40S TO HOLD ON OVER THE PIEDMONT... WITH
50S SE. SKIES WILL BECOME PARTLY CLOUDY TUESDAY NIGHT WITH CAA
LEADING TO LOWS OF 30-35.
WED-THU... VERY COLD AND STRONG ARCTIC HIGH PRESSURE WILL AFFECT THE
UPPER MIDWEST AND GREAT LAKES. THIS HIGH PRESSURE IS FORECAST TO
BUILD SOUTH INTO NC THIS PERIOD. HOWEVER... THE CORE OF THE ARCTIC
AIR IS FORECAST TO REMAIN FROM AROUND NORTHERN VA NORTHWARD. YET...
THE FEED OF DRY AND COLD AIR WILL ALLOW TEMPS TO FALL BELOW NORMAL
WED NIGHT AND THURSDAY. MOSTLY CLEAR SKIES ARE EXPECTED WED-THU...
HIGHS WED SHOULD BE IN THE UPPER 40S TO MID 50S... COOLING INTO THE
MID 40S TO LOWER 50S THURSDAY. LOWS WED SHOULD BE 25-30.
BY FRIDAY... ANOTHER STORM SYSTEM IS EXPECTED TO FOLLOW THE SAME
GENERAL TRACK AS THE LAST SEVERAL STORMS... FROM THE PLAINS TO THE
GREAT LAKES. HOWEVER... THE LARGE COLD SURFACE HIGH SHOULD BE
LOCATED OVER NEW ENGLAND THU NIGHT... THEN SLOWLY DRIFT EAST BY
FRIDAY AND FRIDAY NIGHT. THE HIGH IS FORECAST TO BE MORE THAN STRONG
ENOUGH... AND IN MORE THAN ADEQUATE POSITION TO FAVOR A CLASSICAL TO
HYBRID CAD EVENT FOR FRI-FRI NIGHT AS THE PRECIPITATION ASSOCIATED
WITH THE STORM SYSTEM ARRIVES FROM THE WEST. FOR NOW... IT DOES
APPEAR TO BE WARM ENOUGH FOR RAIN... ALTHOUGH THIS WILL HAVE TO BE
WATCHED CLOSELY FOR FRIDAY. LOWS 30-35. HIGHS 38-48 NW TO SE.
THE FRONT SHOULD SETTLE SOUTH OF THE REGION OVER THE WEEKEND... WITH
ANOTHER POTENTIAL STORM WITH SIGNIFICANT PRECIPITATION OVER THE SE
INTO THE MID-ATLANTIC LATER IN THE WEEKEND. THE POTENTIAL STORM
TRACK FROM THE GULF TO THE SE STATES ALLOWS POTENTIAL FOR WINTERY
PRECIP INTO THE MID-ATLANTIC STATES... BUT THE QUESTION WILL BE THE
POSITION AND STRENGTH OF THE SURFACE HIGH THAT WILL FOLLOW THE
FRONT FRIDAY... AND HOW FAR SOUTH THE COLD AIR CAN REACH.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 625 AM SUNDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL RULE THROUGH THE TAF PERIOD AS AN INTENSIFYING
LOW PRESSURE SYSTEM TRACKS FURTHER OFFSHORE INTO THE ATLANTIC. THE
PRIMARY AVIATION CONCERN WILL BE BREEZY WNW/NW WINDS TODAY...
SUSTAINED AT 15 KT WITH GUSTS GENERALLY TO 25 KT...THOUGH A PERIOD
OF STRONGER WINDS SUSTAINED AT 20 KT WITH GUSTS UP TO 30 KT WILL BE
POSSIBLE...PRIMARILY BETWEEN 12-18Z...ESPECIALLY AT THE RWI
TERMINAL. WINDS WILL DECREASE TO 5-10 KT AFTER 21Z...BECOMING LIGHT
AND VARIABLE AFTER 00Z.
LOOKING AHEAD:
VFR CONDITIONS WILL RULE THROUGH MONDAY IN ASSOCIATION WITH DRY HIGH
PRESSURE. HIGH PRESSURE WILL MOVE OFFSHORE MONDAY NIGHT AS A COLD
FRONT APPROACHES THE MOUNTAINS FROM THE WEST. EXPECT DETERIORATING
CONDITIONS WITH MVFR/IFR CEILINGS DEVELOPING IN ASSOC/W AN
INCREASINGLY MOIST RETURN FLOW BETWEEN 06-12Z TUE AND INCREASING
CHANCES FOR RAIN FROM WEST-EAST BETWEEN 12-18Z TUE. A PERIOD OF
SOUTHWESTERLY LOW LEVEL WIND SHEAR WILL BE POSSIBLE BETWEEN 06Z TUE
MORNING AND 18Z TUE AFTERNOON AS A 40-45 KT LLJ DEVELOPS AS LOW DOWN
AS 1500-2000 FT AGL. EXPECT RAPID CLEARING AND A RETURN TO VFR
CONDITIONS IN THE WAKE OF THE COLD FRONTAL PASSAGE LATE TUE INTO TUE
NIGHT. VFR CONDITIONS WILL PREVAIL THROUGH THURSDAY AS DRY HIGH
PRESSURE BUILDS OVER THE CAROLINAS. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
949 AM EST SUN FEB 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA TODAY. AS IT PUSHES OFF TO
THE EAST THROUGH THE DAY ON MONDAY...INCREASING SOUTHERLY WINDS
WILL PULL WARMER AIR INTO THE REGION. RAIN WILL OVERSPREAD THE
AREA MONDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED THE FORECAST TO ACCOUNT FOR PESKY BANDS OF LOW CLOUDS AND
FLURRIES ACROSS WCNTL/CNTL OHIO. 17.12Z KILN SOUNDING WAS QUITE
DRY /PWAT 0.09 INCH/ SUGGESTING MOISTURE IS VERY THIN/SHALLOW BUT
GIVEN VERY COLD THICKNESSES AND NWLY LOW LEVEL FLOW THERE IS STILL
ENOUGH TO WRING OUT A LITTLE -SN ACTIVITY. WITH RAP 900MB FLOW
STILL NNWLY THROUGH MIDDAY EXPECT CLOUDS TO BUILD/DEVELOP SLOWLY
SOUTHEAST THROUGH REMAINDER OF CNTL INTO SCNTL OHIO THROUGH EARLY
AFTERNOON...AND MAY NEED TO UPDATE FORECAST TO BE A LITTLE MORE
BULLISH ON CLOUD COVER IN COMPARISON TO THIS UPDATE. WITH 925MB
TEMPS STILL -14C...AND FLOW NOT EXPECTED TO BACK AROUND TO W/SW
UNTIL MID AFTN...HAVE DROPPED FCST MAX TEMPS A DEGREE OR TWO ALL
AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
HIGH PRESSURE WILL SLIDE EAST OF THE AREA TONIGHT WITH RETURN FLOW
SETTING UP FOR MONDAY AHEAD OF AN APPROACHING COLD FRONT. GOOD WAA
WILL DEVELOP THROUGH THE DAY ON MONDAY AS A 40-50 KNOT 925 JET WORKS
IN FROM THE WEST THROUGH THE AFTERNOON. THIS WILL HELP PUSH
TEMPERATURES WELL ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER
40S NORTH TO LOWER/MID 50S ACROSS THE SOUTH.
IN A DEVELOPING ISENTROPIC FLOW PATTERN...A FEW SHOWERS COULD
SNEAK INTO OUR WEST LATE IN THE DAY. HOWEVER...BULK OF PCPN SHOULD
HOLD OFF UNTIL MONDAY EVENING WHEN IT OVERSPREADS OUR AREA FROM
THE WEST AND THEN CONTINUES THROUGH THE OVERNIGHT HOURS. THE COLD
FRONT WILL PUSH IN FROM THE WEST LATE MONDAY NIGHT. THIS WILL
ALLOW FOR TEMPERATURES TO DROP OFF QUICKLY ACROSS THE WEST
LATE...WITH RAIN STARTING TO MIX WITH/CHANGE TO SNOW. GOOD CAA
WILL OVERSPREAD THE AREA THROUGH TUESDAY MORNING WITH ANY
LINGERING RAIN CHANGING OVER TO ALL SNOW. AS DRIER AIR MOVES IN
FROM THE WEST...PCPN SHOULD TAPER OFF TO A FEW SHOWERS HEADING
THROUGH THE REST OF THE DAY. EXPECT ANY SNOW ACCUMULATIONS TO BE ON
THE LIGHT SIDE AS MORE SIGNIFICANT PCPN SHOULD BE ENDING AS
THE COLDER AIR WORKS IN. GIVEN THE GOOD CAA ON TUESDAY...DO NOT
EXPECT MUCH TEMPERATURE RECOVERY...WITH EARLY HIGHS LIKELY ACROSS
THE EAST WITH TEMPERATURES THEN FALLING OFF THROUGH THE REST OF
THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE BUILDS DOWN INTO THE LOWER OHIO VALLEY TUE NIGHT
INTO WED BEFORE LIFTING NE ACROSS THE FA WED NGT. THIS SHOULD
PROVIDE DRY CONDITIONS FOR THE PERIOD...WITH NRN SECTIONS SEEING
MORE CLOUDS THAN THE S TUE NGT AND WED...BEFORE MOSTLY CLEAR SKIES
PREVAIL WED NGT.
SYSTEM DIGS INTO THE SRN ROCKIES WED NGT...THEN EJECTS OUT THU
INTO THU NGT. MODELS ARE SHOWING THEIR TYPICAL SPREAD. THE CMC IS
THE QUICKEST THIS RUN IN BRINGING RETURN PCPN TO THE FA THU AFTN.
THE 12Z RUNS OF THE GFS AND ECMWF ARE SLOWER...LIMITING POPS TO
THE SW. THICKNESSES WILL BE COLD ENUF FOR SOME RAIN/SNOW AT THE
ONSET. AS THE CENTER OF THE SYSTEM LIFTS OUT THRU THE PLAINS...AN
AREA OF PCPN WILL BE PUSHED ACROSS THE FA THU NGT INTO FRI. PCPN
WILL EITHER BE SN OR RA/SN MIX UNTIL A WRMFNT GRADUALLY BRINGS IN
WARMER AIR CHANGING THE PCPN TO RA BEFORE IT ENDS ON FRIDAY. HIGH
PRESSURE THEN BUILDS IN FOR FRIDAY.
COLD AIR WILL WORK IN TUESDAY NIGHT DROPPING TEMPERATURES IN THE
TEENS AND LOWER 20S. THE COOL NLY FLOW ON WED WILL KEEP TEMPS DOWN
IN THE UPPER 20S N TO THE MID 30S NRN KY. THE CLEAR SKIES WILL
ALLOW TEMPERATURES TO DROP BACK INTO THE TEENS AND LOWER 20S
AGAIN. ONLY EXPECT HIGHS ON THU TO MAKE THE 30S AHEAD OF THE STORM
SYSTEM...BUT WITH RISING TEMPS THU NGT. HIGHS FRIDAY SHOULD MAKE
THE 40S AS THE REGION GETS WARM SECTORED.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
LINGERING LOW LEVEL MOISTURE DUE TO NORTHWESTERLY FLOW OFF THE
GREAT LAKES WILL BRING A MIX OF VFR AND MVFR CLOUDS ACROSS THE
AREA THROUGHOUT THE DAY. THE BEST CHANCE FOR MVFR CIGS WILL BE
ACROSS THE NORTH...CLOSER TO THE LAKES. AS HIGH PRESSURE SHIFTS
EAST OF OUR AREA THIS EVENING...NORTHWESTERLY FLOW WILL
CEASE...AND SOUTHERLY FLOW WILL BEGIN TO DEVELOP. AS THIS
OCCURS...LOW LEVEL CLOUDS WILL DECREASE. THIS SHOULD RESULT IN VFR
CONDITIONS FOR ALL TERMINALS FROM THIS EVENING THROUGH SUNDAY
MORNING.
OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE MONDAY NIGHT AND EARLY
TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...BINAU
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1024 AM EST SUN FEB 17 2013
.SYNOPSIS...
HIGH PRESSURE IS GOING TO MOVE EAST AND COVER THE AREA BY TONIGHT.
THIS HIGH LINGERS INTO MONDAY...SHIFTING OFF THE COAST MONDAY
AFTERNOON. A COLD FRONT WILL MOVE INTO THE AREA EARLY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 AM EST SUNDAY...
WIND CHILL ADVISORY WAS ALLOWED TO EXPIRE FOR THE SOUTHWEST VA/SRN
WV MTNS THIS MORNING. WIND CHILLS IN MOST PLACES ARE WARMER THAN 5
BELOW OUTSIDE THE HIGHEST PEAKS.
DEALING WITH A SHORTWAVE THAT IS MOVING NORTHEAST OVER THE AREA
THIS MORNING. MOST OF THE SNOW SHOWERS HAVE TAPERED OFF EAST OF
THE UPSLOPE ZONES. THINK THE NAM/LOCAL WRF USUALLY DO A BETTER JOB
OF LEAVING SNOW SHOWERS IN LONGER AND WILL SEE SNOW SHOWERS
LINGERING TIL ABOUT EARLY AFTERNOON OVER THE NC MTNS...BEFORE
ENDING. HOWEVER...DO NOT FORESEE ANY ACCUMULATIONS ABOVE AN INCH
SO WILL MORE THAN LIKELY ALLOW THE ADVISORY FOR THE HIGHER
ELEVATIONS TO EXPIRE AT NOON. THERE WILL BE SOME BANDING STILL
GOING ON THROUGH THE AFTERNOON NORTH OF A RICHLANDS TO BURKES
GARDEN LINE...THINKING THE HIGHER SLOPES OF MERCER TO GREENBRIER
RECEIVE AT LEAST ANOTHER INCH IF NOT MORE BEFORE MOISTURE
DIMINISHES AROUND DUSK.
TEMPERATURES/WIND CHILLS ARE GOING TO STAY VERY COLD TODAY AND DO
NOT FORESEE THE HIGHER ELEVATIONS MAKING IT OUT OF THE LOWER
TEENS. MOST AREAS WEST OF THE BLUE RIDGE SHOULD REACH THE
20S...WHILE THE EAST GETS TO AT LEAST FREEZING. SNOW COVER EAST OF
LYH MAY HOLD TEMPS DOWN THERE SOME.
LATEST RAP AND LOCAL WRF CONTINUED TO SHOW BANDS OF SNOW SHOWERS
ACROSS THE MOUNTAINS...AND FOR A FEW HOURS THIS MORNING. SPILLING
INTO FRANKLIN...HENRY AND PATRICK COUNTIES. VISIBILITIES WERE
DROPPING TO AROUND A MILE UNDER THE HEAVY SNOW BANDS. HAVE SPREAD
THE FORECAST FOR ACCUMULATING SNOW LATER INTO THE MORNING FOR THE
WESTERN UPSLOPE COUNTIES AND THE NEW RIVER VALLEY.
BUFKIT SHOWED THE POTENTIAL FOR WIND GUSTS AROUND 40 KNOTS AT TNB
BUT ONLY 30 KNOTS FOR MOST OTHER LOCATIONS. NO WIND ADVISORY
PLANNED FOR NOW. JUST HIGHLIGHTED WINDS IN THE ONGOING WINTER
WEATHER ADVISORY.
PREVIOUS VALID DISCUSSION...
ONCE THE SUN SETS...WIND SPEEDS ARE EXPECTED TO DROP OFF TO LESS
THAN 10 MPH SO EVEN THOUGH OVERNIGHT LOW TEMPERATURES WILL AGAIN
BE IN THE SINGLE DIGITS TO AROUND 20...THE WIND CHILL WILL NOT BE
A FACTOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
ON MONDAY...WE WILL HAVE ONE DRY AND MILDER...AND LESS WINDY DAY AS
HIGH PRESSURE BUILDS OVER THE REGION. WE EXPECTING HIGHS IN THE MID
TO UPPER 40S ACROSS THE MOUNTAINS WITH UPPER 40S EAST OF THE CREST
OF THE BLUE RIDGE.
MONDAY NIGHT THROUGH TUESDAY...A QUICK MOVING COLD FRONT WILL
APPROACH AND THEN CROSS THE REGION. WE WILL FIRST EXPERIENCE
INCREASING CLOUD COVER MONDAY EVENING...AND THEN PRECIPITATION WILL
MOVE INTO THE REGION FROM THE WEST AFTER MIDNIGHT AHEAD OF THE COLD
FRONT. THE PRECIPITATION WILL BE ACCOMPANIED BY A WARM NOSE ALOFT
OVER A MIX OF ABOVE AND BELOW TEMPERATURES AT THE SURFACE. MODEL
GUIDANCE HAS TRENDED COLDER WITH THE MAGNITUDE OF THE WARM NOSE. WE
ARE SEEING A TREND TOWARDS MORE SNOW AND SLEET ACROSS THE MOUNTAINS
AND THE NORTHERN THIRD OF THE FORECAST AREA LATE MONDAY NIGHT INTO
EARLY TUESDAY MORNING. AFTER ROUGHLY 9 OR 10 AM
TUESDAY...TEMPERATURES WILL BE MILD ENOUGH FOR MOST OF THE AREA TO
RECEIVE RAIN. THERE STILL MAY BE SOME SNOW IN WESTERN GREENBRIER
COUNTY WV THROUGH THE DAYTIME TUESDAY. BY TUESDAY AFTERNOON...THE
COLD FRONT WILL BE HEADING EAST OF THE FORECAST AREA AND THE
PRECIPITATION WILL BEGIN TO BECOME CONFINED TO THE UPSLOPE REGIONS
OF SOUTHEAST WEST VIRGINIA. AS WE HEAD INTO TUESDAY NIGHT...THIS
PRECIPITATION WILL QUICKLY TRANSITION INTO SNOW SHOWERS...BUT
TREND TOWARDS DECREASING COVERAGE THROUGH THE NIGHT. THE REMAINDER
OF THE FORECAST AREA WILL BE PRECIPITATION FREE.
WE ARE STILL CONCERNED ABOUT GUSTY/DAMAGING WINDS AHEAD OF THE FRONT
ON TUESDAY AND THEN BEHIND THE FRONT TUESDAY NIGHT. MODEL GUIDANCE
PLACES A SOUTHWEST 850 MB JET AROUND 60 TO 65 KTS JUST IN ADVANCE OF
THE FRONT. SOME STRONGER GUSTS MAY BE ABLE TO ACCOMPANY THE HEAVIER
SHOWERS TO THE SURFACE. TUESDAY NIGHT...NORTHWEST 850 MB WINDS OF 50
KTS ARE EXPECTED BY MIDNIGHT...AND 50 TO 60 KTS ARE EXPECTED BY
SUNRISE WEDNESDAY. CONFIDENCE IS GROWING FOR THE POTENTIAL FOR AT
LEAST A WIND ADVISORY TUESDAY AND THEN AGAIN TUESDAY NIGHT INTO
EARLY WEDNESDAY.
WEDNESDAY INTO WEDNESDAY NIGHT...A DRY FORECAST IS EXPECTED AND
WINDS WILL EXPERIENCE A GRADUAL DECREASE AS THE CENTER OF HIGH
PRESSURE DRAWS CLOSER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 320 PM EST SATURDAY...
BY THURSDAY AFTERNOON...AN INVERTED TROUGH WILL DEVELOP ACROSS
EASTERN KENTUCKY AND WEST VIRGINIA. THIS WILL ALLOW THE WINDS TO
BECOME EASTERLY WITH UNIFORM TEMPERATURES IN THE 40S ACROSS THE
AREA.
A WARM FRONT WILL OVERRUN THIS SURFACE RIDGE THURSDAY NIGHT WITH
PRECIPITATION TRACKING FROM SOUTHWEST TO NORTHEAST. THIS
PRECIPITATION WILL BE FALLING INTO DRY AIR WITH DEW POINTS IN THE
UPPER TEENS TO MID 20S. INITIAL P-TYPE WILL BE A BRIEF PERIOD OF
SLEET FOLLOWED BY RAIN AND FREEZING RAIN. FORECAST SOUNDINGS
CONTINUES TO SUPPORT FREEZING RAIN FRIDAY MORNING. CHANCES OF
FREEZING RAIN ARE MORESO ALONG THE EASTERN SLOPES OF THE BLUE
RIDGE AND POSSIBLY ACROSS THE GREENBRIER AND SOUTH SHENANDOAH
VALLEY. CONVECTION TRACKING ACROSS THE SOUTHEASTERN US MAY KEEP
RAIN/ICE AMOUNTS LOWER THAN CURRENTLY FORECASTED BY THE MODELS.
THE GFS/ECMWF HAS A QUARTER TO A HALF INCH OF LIQUID WITH THIS
SYSTEM.
BULK OF THE PRECIPITATION WILL MOVE EAST FRIDAY
AFTERNOON...HOWEVER...THE INSITU WEDGE WITH COLD...GRAY...DAMP
CONDITIONS MAY LINGER ACROSS THE PIEDMONT INTO FRIDAY NIGHT. AS
THE WEDGE BREAKS...TEMPERATURES WILL WARM ABOVE FREEZING. FOG
COULD THEN BECOME A PROBLEM FRIDAY NIGHT INTO SATURDAY MORNING. BY
SATURDAY AFTERNOON...THE WINDS BECOME WESTERLY WITH TEMPERATURES
POSSIBLY WARMING ABOVE NORMAL.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 655 AM EST SUNDAY...
NORTHWEST WINDS WILL CONTINUE TO PRODUCE BANDS OF SNOW SHOWERS
OVER THE MOUNTAINS. WITHIN THE BANDS OF SNOW VISIBILITIES DROP TO
LESS THAN ONE MILE AND CEILINGS DROP BELOW 1000 FT AGL...SO EXPECT
THESE CONDITIONS IF ONE OF THESE BANDS TRACKS DIRECTLY OVER AN
AIRPORT. BLF AND LWB HAVE THE GREATEST CHANCE FOR SNOW THIS
MORNING...AND THE CHANCE AT ROA AND BCB WILL BE LOWER.
BUFKIT SHOULD WIND GUSTS TODAY REACHING 30 TO 40 KNOTS IN THE
MOUNTAINS...ESPECIALLY AT HIGHER ELEVATIONS ALONG THE SOUTHERN
BLUE RIDGE. EAST OF THE BLUE RIDGE...INCLUDING AT ROA...PLAN
ON WIND GUSTS MAINLY FROM 20 TO 30 KNOTS.
HIGH PRESSURE WILL BUILD IN FOR TONIGHT AND MONDAY MORNING. AFTER
SUNSET WINDS WILL DIMINISH AND THE SKY WILL BE CLEAR. HIGH
CONFIDENCE FOR VFR CONDITIONS THROUGH THE END OF THE DAY ON
MONDAY.
A COLD FRONT WILL APPROACH THE AREA EARLY TUESDAY...WITH A MIX OF
WINTER PRECIPITATION POSSIBLE IN THE MOUNTAINS STARTING LATE
MONDAY NIGHT. EXPECT IFR CONDITIONS WITH THIS PRECIPITATION AND
STRONGER WINDS AHEAD OF THE FRONT ON TUESDAY. GUSTY WINDS WILL
CONTINUE BEHIND THE FRONT ON TUESDAY NIGHT AND WEDNESDAY. HIGH
PRESSURE WILL THEN BUILD IN FOR THURSDAY ALLOWING FOR VFR WEATHER.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ001-018.
WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
WVZ045.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...AMS/WP
SHORT TERM...DS
LONG TERM...RCS
AVIATION...AMS/DS/JH
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
703 AM EST SUN FEB 17 2013
.SYNOPSIS...
LOW PRESSURE WAS WELL OFF THE NEW JERSEY COAST THIS MORNING.
HIGH PRESSURE WAS CENTERED OVER MISSISSIPPI AND ALABAMA. THIS HIGH
WILL COVER MUCH OF THE MID ATLANTIC REGION AND SOUTHEAST UNITED
STATES THROUGH MONDAY MORNING. A COLD FRONT WILL MOVE INTO THE
AREA EARLY TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 440 AM EST SUNDAY...
LATEST RAP AND LOCAL WRF CONTINUED TO SHOW BANDS OF SNOW SHOWERS
ACROSS THE MOUNTAINS...AND FOR A FEW HOURS THIS MORNING. SPILLING
INTO FRANKLIN...HENRY AND PATRICK COUNTIES. VISIBILITIES WERE
DROPPING TO AROUND A MILE UNDER THE HEAVY SNOW BANDS. HAVE SPREAD
THE FORECAST FOR ACCUMULATING SNOW LATER INTO THE MORNING FOR THE
WESTERN UPSLOPE COUNTIES AND THE NEW RIVER VALLEY.
BUFKIT SHOWED THE POTENTIAL FOR WIND GUSTS AROUND 40 KNOTS AT TNB
BUT ONLY 30 KNOTS FOR MOST OTHER LOCATIONS. NO WIND ADVISORY
PLANNED FOR NOW. JUST HIGHLIGHTED WINDS IN THE ONGOING WINTER
WEATHER ADVISORY.
850 MB TEMPERATURES THIS MORNING SHOULD BE IN THE -14 TO -18
DEGREE CELCIUS RANGE. HAVE ISSUED A WIND CHILL ADVISORY FROM
TAZEWELL COUNTY INTO GRAYSON COUNTY WHERE WINDS CHILLS WILL MEET
CRITERIA THIS MORNING.
SURFACE HIGH PRESSURE WILL BUILD OVER THE SOUTHEAST UNITED STATES
THIS AFTERNOON. THIS WILL RESULT IN DIMINISHING WINDS AND
DECREASING COVERAGE OF SNOW SHOWERS. ONCE THE SUN SETS...WIND
SPEEDS ARE EXPECTED TO DROP OFF TO LESS THAN 10 MPH SO EVEN THOUGH
OVERNIGHT LOW TEMPERATURES WILL AGAIN BE IN THE SINGLE DIGITS TO
AROUND 20...THE WIND CHILL WILL NOT BE A FACTOR.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 330 AM EST SUNDAY...
ON MONDAY...WE WILL HAVE ONE DRY AND MILDER...AND LESS WINDY DAY AS
HIGH PRESSURE BUILDS OVER THE REGION. WE EXPECTING HIGHS IN THE MID
TO UPPER 40S ACROSS THE MOUNTAINS WITH UPPER 40S EAST OF THE CREST
OF THE BLUE RIDGE.
MONDAY NIGHT THROUGH TUESDAY...A QUICK MOVING COLD FRONT WILL
APPROACH AND THEN CROSS THE REGION. WE WILL FIRST EXPERIENCE
INCREASING CLOUD COVER MONDAY EVENING...AND THEN PRECIPITATION WILL
MOVE INTO THE REGION FROM THE WEST AFTER MIDNIGHT AHEAD OF THE COLD
FRONT. THE PRECIPITATION WILL BE ACCOMPANIED BY A WARM NOSE ALOFT
OVER A MIX OF ABOVE AND BELOW TEMPERATURES AT THE SURFACE. MODEL
GUIDANCE HAS TRENDED COLDER WITH THE MAGNITUDE OF THE WARM NOSE. WE
ARE SEEING A TREND TOWARDS MORE SNOW AND SLEET ACROSS THE MOUNTAINS
AND THE NORTHERN THIRD OF THE FORECAST AREA LATE MONDAY NIGHT INTO
EARLY TUESDAY MORNING. AFTER ROUGHLY 9 OR 10 AM
TUESDAY...TEMPERATURES WILL BE MILD ENOUGH FOR MOST OF THE AREA TO
RECEIVE RAIN. THERE STILL MAY BE SOME SNOW IN WESTERN GREENBRIER
COUNTY WV THROUGH THE DAYTIME TUESDAY. BY TUESDAY AFTERNOON...THE
COLD FRONT WILL BE HEADING EAST OF THE FORECAST AREA AND THE
PRECIPITATION WILL BEGIN TO BECOME CONFINED TO THE UPSLOPE REGIONS
OF SOUTHEAST WEST VIRGINIA. AS WE HEAD INTO TUESDAY NIGHT...THIS
PRECIPITATION WILL QUICKLY TRANSITION INTO SNOW SHOWERS...BUT
TREND TOWARDS DECREASING COVERAGE THROUGH THE NIGHT. THE REMAINDER
OF THE FORECAST AREA WILL BE PRECIPITATION FREE.
WE ARE STILL CONCERNED ABOUT GUSTY/DAMAGING WINDS AHEAD OF THE FRONT
ON TUESDAY AND THEN BEHIND THE FRONT TUESDAY NIGHT. MODEL GUIDANCE
PLACES A SOUTHWEST 850 MB JET AROUND 60 TO 65 KTS JUST IN ADVANCE OF
THE FRONT. SOME STRONGER GUSTS MAY BE ABLE TO ACCOMPANY THE HEAVIER
SHOWERS TO THE SURFACE. TUESDAY NIGHT...NORTHWEST 850 MB WINDS OF 50
KTS ARE EXPECTED BY MIDNIGHT...AND 50 TO 60 KTS ARE EXPECTED BY
SUNRISE WEDNESDAY. CONFIDENCE IS GROWING FOR THE POTENTIAL FOR AT
LEAST A WIND ADVISORY TUESDAY AND THEN AGAIN TUESDAY NIGHT INTO
EARLY WEDNESDAY.
WEDNESDAY INTO WEDNESDAY NIGHT...A DRY FORECAST IS EXPECTED AND
WINDS WILL EXPERIENCE A GRADUAL DECREASE AS THE CENTER OF HIGH
PRESSURE DRAWS CLOSER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 320 PM EST SATURDAY...
BY THURSDAY AFTERNOON...AN INVERTED TROUGH WILL DEVELOP ACROSS
EASTERN KENTUCKY AND WEST VIRGINIA. THIS WILL ALLOW THE WINDS TO
BECOME EASTERLY WITH UNIFORM TEMPERATURES IN THE 40S ACROSS THE
AREA.
A WARM FRONT WILL OVERRUN THIS SURFACE RIDGE THURSDAY NIGHT WITH
PRECIPITATION TRACKING FROM SOUTHWEST TO NORTHEAST. THIS
PRECIPITATION WILL BE FALLING INTO DRY AIR WITH DEW POINTS IN THE
UPPER TEENS TO MID 20S. INITIAL P-TYPE WILL BE A BRIEF PERIOD OF
SLEET FOLLOWED BY RAIN AND FREEZING RAIN. FORECAST SOUNDINGS
CONTINUES TO SUPPORT FREEZING RAIN FRIDAY MORNING. CHANCES OF
FREEZING RAIN ARE MORESO ALONG THE EASTERN SLOPES OF THE BLUE
RIDGE AND POSSIBLY ACROSS THE GREENBRIER AND SOUTH SHENANDOAH
VALLEY. CONVECTION TRACKING ACROSS THE SOUTHEASTERN US MAY KEEP
RAIN/ICE AMOUNTS LOWER THAN CURRENTLY FORECASTED BY THE MODELS.
THE GFS/ECMWF HAS A QUARTER TO A HALF INCH OF LIQUID WITH THIS
SYSTEM.
BULK OF THE PRECIPITATION WILL MOVE EAST FRIDAY
AFTERNOON...HOWEVER...THE INSITU WEDGE WITH COLD...GRAY...DAMP
CONDITIONS MAY LINGER ACROSS THE PIEDMONT INTO FRIDAY NIGHT. AS
THE WEDGE BREAKS...TEMPERATURES WILL WARM ABOVE FREEZING. FOG
COULD THEN BECOME A PROBLEM FRIDAY NIGHT INTO SATURDAY MORNING. BY
SATURDAY AFTERNOON...THE WINDS BECOME WESTERLY WITH TEMPERATURES
POSSIBLY WARMING ABOVE NORMAL.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 655 AM EST SUNDAY...
NORTHWEST WINDS WILL CONTINUE TO PRODUCE BANDS OF SNOW SHOWERS
OVER THE MOUNTAINS. WITHIN THE BANDS OF SNOW VISIBILITIES DROP TO
LESS THAN ONE MILE AND CEILINGS DROP BELOW 1000 FT AGL...SO EXPECT
THESE CONDITIONS IF ONE OF THESE BANDS TRACKS DIRECTLY OVER AN
AIRPORT. BLF AND LWB HAVE THE GREATEST CHANCE FOR SNOW THIS
MORNING...AND THE CHANCE AT ROA AND BCB WILL BE LOWER.
BUFKIT SHOULD WIND GUSTS TODAY REACHING 30 TO 40 KNOTS IN THE
MOUNTAINS...ESPECIALLY AT HIGHER ELEVATIONS ALONG THE SOUTHERN
BLUE RIDGE. EAST OF THE BLUE RIDGE...INCLUDING AT ROA...PLAN
ON WIND GUSTS MAINLY FROM 20 TO 30 KNOTS.
HIGH PRESSURE WILL BUILD IN FOR TONIGHT AND MONDAY MORNING. AFTER
SUNSET WINDS WILL DIMINISH AND THE SKY WILL BE CLEAR. HIGH
CONFIDENCE FOR VFR CONDITIONS THROUGH THE END OF THE DAY ON
MONDAY.
A COLD FRONT WILL APPROACH THE AREA EARLY TUESDAY...WITH A MIX OF
WINTER PRECIPITATION POSSIBLE IN THE MOUNTAINS STARTING LATE
MONDAY NIGHT. EXPECT IFR CONDITIONS WITH THIS PRECIPITATION AND
STRONGER WINDS AHEAD OF THE FRONT ON TUESDAY. GUSTY WINDS WILL
CONTINUE BEHIND THE FRONT ON TUESDAY NIGHT AND WEDNESDAY. HIGH
PRESSURE WILL THEN BUILD IN FOR THURSDAY ALLOWING FOR VFR WEATHER.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND CHILL ADVISORY UNTIL 10 AM EST THIS MORNING FOR VAZ007-
009-010-012-015.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ001-018.
WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
WVZ045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...DS
LONG TERM...RCS
AVIATION...AMS/DS/JH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
305 PM MST SUN FEB 17 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW SHORTWAVE RIDGE OVER
THE CWA...WITH SHORTWAVE TROUGH ACROSS THE NORTHERN ROCKIES
EXTENDING SOUTH OVER THE GREAT BASIN. AT THE SURFACE A STRONG COLD
FRONT EXTENDS FROM NORTH DAKOTA ACROSS EASTERN WYOMING AND SOUTH
ACROSS EASTERN UTAH. STRONG SUBSIDENCE IS ALREADY APPARENT ON WV
IMAGERY BEHIND THIS FRONT.
CLOUD COVER HAS REMAINED IN PLACE OVER THE CWA...WHICH HAS
RESTRICTED MIXING RESULTING IN WEAKER WINDS THAN ORIGINALLY
EXPECTED. RH VALUES HAVE DROPPED WELL BELOW RFW CRITERIA ACROSS THE
REGION...WITH SINGLE DIGIT RH VALUES AT MANY LOCATIONS. ONLY A FEW
LOCATIONS SO FAR HAVE REACHED WIND CRITERIA FOR WIND...WITH MANY
OTHER LOCATIONS BORDERLINE. I PLAN ON LEAVING THE RFW IN PLACE FOR
NOW...DUE TO HOW DRY WE ARE...AND THE POTENTIAL FOR WINDS TO
INCREASE BETWEEN NOW AND 00Z.
A STRONG COLD FRONT OVER THE NORTHERN PLAINS WILL DROP SOUTH OVER
THE CWA THIS EVENING AND OVERNIGHT. GFS/NAM BOTH INDICATE 40-50KT
WINDS BEHIND THIS FRONT OVER OUR CWA...WITH BL WINDS 20-30KT. STRONG
PRESSURE GRADIENT COMBINED WITH STRONG SUBSIDENCE SHOULD HELP BRING
WINDS TO THE SURFACE. WHILE THESE CONDITIONS MAY ONLY LAST AN HOUR
OR TWO AT THE MOST...I WAS CONFIDENT ENOUGH TO ISSUE WIND ADVISORY
FOR THE SUDDEN ONSET OF GUSTS TO 55 MPH AND THE POSSIBILITY OF
BLOWING DUST STARTING AT 03Z. ORIGINALLY I CONSIDERING EXTENDING
THIS ADVISORY THROUGH THE DAY TOMORROW. HOWEVER...PRESSURE GRADIENT
SHOULD BEGIN TO RELAX AS FRONT MOVES SOUTH AND EAST...AND DAYTIME
MIXING IS STILL IN QUESTION IF CLOUDS LINGER THROUGH THE DAY. I
HAVE CURRENT ADVISORY ENDING AT 12Z TO ALLOW NEXT SHIFTS TO
REEVALUATE FOR TOMORROW.
STRONG FORCING AND DECENT MID LEVEL MOISTURE WILL BE IN PLACE
OVERNIGHT WITH SHORTWAVE TROUGH PASSAGE...HOWEVER LOWER LEVELS
REMAIN VERY DRY. GFS/ECMWF ARE SHOWING LIGHT QPF IN THE WEST...WITH
GEM CREATING A BULLSEYE IN THE NORTHEAST. WHILE I COULDNT RULE OUT A
FEW FLURRIES OR SPRINKLES...I WAS NOT CONFIDENT ENOUGH THAT ANYTHING
WOULD REACH THE GROUND...SO I LEFT MENTION OUT.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 229 PM MST SUN FEB 17 2013
LONG TERM FOCUS REMAINS ON THE UPPER 4-CORNERS LOW EMERGING EAST
OF THE ROCKIES OVER THE HIGH PLAINS IN THE VICINITY OF NORTHEAST
NEW MEXICO/SOUTHEAST COLORADO/SOUTHWEST KANSAS EARLY THURSDAY
MORNING. MODELS HAVE REMAINED CONSISTENT WITH EACH OTHER AND HAVE
ONLY VARIED SLIGHTLY WITH LOW CENTER PLACEMENT FROM RUN TO RUN.
AM THEREFORE CONFIDENT WITH WIDESPREAD PRECIPITATION SHOWN ACROSS
THE ENTIRE FORECAST AREA AND AM CONFIDENT IN STAYING WITH THE
HIGHER POPS FOR THIS EVENT. TEMPERATURES ARE SOMEWHAT MORE
QUESTIONABLE AS THERE HAS BEEN SOME VARIATION IN TIMING AND EXTENT
OF THE COLD AIR MOVING INTO THE REGION ALONG WITH THE EVENTUAL
CHANGE OVER TO SNOW AND THE POSSIBILITY OF SOME INSTABILITY AND
THUNDER AS THIS EVENT INITIATES.
CONDITIONS WILL REMAIN DRY WITH HIGH TEMPERATURES ON TUESDAY
REMAINING SIMILAR TO MONDAY. OVERNIGHT LOWS WILL BE WARMER
TUESDAY NIGHT/EARLY WEDNESDAY AS CLOUDS BEGIN TO SPREAD EAST OF
THE ROCKIES AHEAD OF THE LOW PRESSURE SYSTEM AS IT MOVES INTO THE
INTERMOUNTAIN REGION. COOLER HIGH PRESSURE AT THE SURFACE WILL
CONTINUE TO SLIDE SOUTH INTO THE PLAINS STATES AND BACK INTO THE
FORECAST AREA FROM THE EAST WITH RETURN FLOW AROUND THE HIGH
BRINGING MORE MOISTURE INTO THE REGION. IT APPEARS A DRYLINE/WARM
FRONT FEATURE MOVES ACROSS THE CENTRAL HIGH PLAINS BY LATE
WEDNESDAY...BRINGING THE POTENTIAL FOR ISOLATED THUNDERSTORMS
ALONG WITH RAIN SHOWERS FOR THE WARMER AREAS WHILE SNOW IS
POSSIBLE MAINLY ACROSS THE NORTHEAST LATE. WEDNESDAY NIGHT/EARLY
THURSDAY THE LOW CENTER MOVES INTO SOUTHWEST KANSAS...WRAPPING
COLDER AIR AND MOISTURE AROUND THE SYSTEM WITH POSSIBLE HEAVY SNOW
ACROSS THE NORTHEAST PORTION OF THE FORECAST AREA DURING THAT
TIME. PRECIPITATION IS EXPECTED TO TAPER OFF DURING THE DAY ON
THURSDAY AND END BY THURSDAY EVENING. WINDS MAY BE GUSTY WITH THE
SYSTEM AND PRODUCE AREA OF BLOWING SNOW.
COLDEST TEMPERATURES OF THE WEEK WILL BE ON THURSDAY AND THURSDAY
NIGHT AS THE SYSTEM MOVES OUT WITH FRESH SNOW AND A POSSIBLE
DECREASE IN SKY COVER OVERNIGHT. CONDITIONS FRIDAY AND SATURDAY
WILL BE DRY WITH TEMPERATURES WARMING GRADUALLY WITH A BRIEF SHORT
WAVE RIDGE ALOFT ON SATURDAY AHEAD OF THE NEXT TROUGH SWINGING
THROUGH THE UPPER FLOW AND ACROSS THE ROCKIES LATE SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1045 AM MST SUN FEB 17 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK.
WINDS WILL BE LIGHT OUT OF THE SOUTHWEST THIS AFTERNOON WITH HIGH
CIRRUS CLOUDS. THIS EVENING A STRONG COLD FRONT WILL PUSH THROUGH
BOTH TAF SITES WITH BREEZY TO GUSTY NORTHWEST WINDS TONIGHT AND
THROUGH TOMORROW. WINDS WILL BE 20-25KTS SUSTAINED OVERNIGHT INTO
TOMORROW WITH GUSTS UP TO 40KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY FROM 8 PM MST /9 PM CST/ THIS EVENING TO 5 AM MST
/6 AM CST/ MONDAY FOR KSZ001>004-013>016-027>029-041-042.
RED FLAG WARNING UNTIL 6 PM MST /7 PM CST/ THIS EVENING FOR
KSZ002>004-013>016-027>029-041-042.
CO...WIND ADVISORY FROM 8 PM THIS EVENING TO 5 AM MST MONDAY FOR
COZ090>092.
RED FLAG WARNING UNTIL 6 PM MST THIS EVENING FOR COZ253-254.
NE...WIND ADVISORY FROM 8 PM MST /9 PM CST/ THIS EVENING TO 5 AM MST
/6 AM CST/ MONDAY FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
428 PM EST SUN FEB 17 2013
.SYNOPSIS...
SNOW SHOWERS WILL DECREASE IN COVERAGE THIS EVENING. HIGH PRESSURE
WILL THEN BUILD IN TONIGHT WITH A COLD NIGHT BEFORE DRY AND WARMER
WEATHER ARRIVING ON MONDAY. A COLD FRONT WILL THEN RETURN A WINTRY
MIX EARLY ON TUESDAY WITH SNOW SHOWERS IN ITS WAKE ON TUESDAY
NIGHT AND EARLY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A MID-LEVEL TROUGH
AXIS CENTERED ACROSS THE JERSEY COAST...LEAVING THE UPPER OHIO
VALLEY IN A NORTHWESTERLY FLOW IN THE WAKE OF THIS FEATURE. AT
850MB...A NORTH-NORTHWESTERLY FLOW IS IN PLACE ACROSS THE
LOWLANDS...WITH MORE OF WESTERLY COMPONENT ACROSS THE LAUREL
HIGHLANDS AND ALLEGHENY FRONT OF WV/PA/MD. AT THE SURFACE...A LOW
PRESSURE SYSTEM IS OFF THE COAST OF NEW ENGLAND WITH A BROAD AREA
OF HIGH PRESSURE EXTENDING FROM THE UPPER MIDWEST TO THE GULF OF
MEXICO. THE COMBINATION OF WEAK VORT ENERGY SWINGING SOUTHEASTWARD
ON THE BACK END OF THE TROUGH ALONG WITH MOISTURE FILTERING IN
FROM LAKE HURON HAS ALLOWED SCATTERED SNOW SHOWERS TO CONTINUE
ACROSS MUCH OF THE AREA...WITH MORE NUMEROUS SNOW SHOWERS WITH
UPSLOPING ACROSS THE RIDGES. WITH THE LOSS OF HEATING AND MOISTURE
PULLING AWAY...SNOW SHOWERS ARE BEGINNING TO DIMINISH.
THIS EVENING...THE UPPER TROUGH WILL PUSH OFF THE EAST COAST
WITH THE AREA REMAINING IN A NORTHWESTERLY FLOW AS HIGH PRESSURE
BEGINS TO BUILD IN FROM THE SOUTHWEST. VORT ENERGY SLIDING
EASTWARD WILL ALLOW FOR SNOW SHOWERS TO CONTINUE TO DIMINISH WITH
MOISTURE BECOMING MORE SHALLOW AND AN INVERSION LOWERING THIS
EVENING...ALLOWING FOR SNOWFALL TO CONTINUE TO DECREASE IN
COVERAGE AND DIMINISH. UPSLOPING WILL ALLOW FOR ACCUMULATING
SNOWFALL TO CONTINUE IN THE EASTERN RIDGES...WITH AN ADDITIONAL
INCH THERE.
TONIGHT...HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST WITH AN
850MB RIDGE MOVING INTO THE AREA AND BRINGING AN END TO LINGERING
UPSLOPING SNOWS FOR THE RIDGES. SKIES WILL CLEAR OUT WITH WINDS
DECREASING TO AROUND 5 MPH. WITH 850MB TEMPS AS COLD AS
16C...ALONG WITH CLEARING AND DECREASED WINDS CONTRIBUTING TO SOME
RADIATIONAL COOLING...LOWS TONIGHT WILL RANGE FROM THE SINGLE
DIGITS ACROSS THE HIGHER ELEVATIONS TO THE MID TEENS ACROSS THE
LOWLANDS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
A MODEL CONSENSUS INDICATES A MID-LEVEL RIDGE CROSSING THE AREA ON
MONDAY WITH HIGH PRESSURE PASSING SOUTHWARD. THIS WILL ALLOW FOR A
DRY DAY WITH ABUNDANT SUNSHINE TO START THE DAY. AS A LOW-LEVEL
RIDGE SHIFTS EAST OF THE AREA...THE FLOW WILL BECOME
SOUTHWESTERLY AND ALLOW FOR WEAK WAA TO ENSUE. THIS ALONG WITH
SUNSHINE WILL CONTRIBUTE TO MAKE HIGHS A FEW DEGREES ABOVE
SEASONAL NORMALS ON MONDAY.
SOME UNCERTAINTY ENTERS THE FORECAST MONDAY NIGHT INTO TUESDAY AS
A COLD FRONT MOVES INTO THE REGION. GFS/NAM INDICATE THAT THERE
WILL BE LITTLE LOW-LEVEL MOISTURE AVAILABLE AHEAD OF THE FRONT WITH
CAA QUICKLY ENSUING AS LOWER LEVELS SATURATE. THUS...ANTICIPATE
A SHORT PERIOD OF MOSTLY RAIN ACROSS THE AREA EARLY TUESDAY WITH
850MB TEMPS WARMING TO 0-4C AND SUFFICIENT FOR MELTING. THE
EXCEPTION AT THE ONSET WILL BE ACROSS THE RIDGES AND NORTHEAST OF
PITTSBURGH WHERE A BRIEF PERIOD OF SLEET AND FREEZING RAIN WILL BE
POSSIBLE AND FZRA MAY LEAD TO BRIEFING ICING AT THE ONSET. PRECIP
WILL THEN QUICKLY TURN TO SNOW BY 18Z ACROSS THE AREA. GIVEN THE
PASSAGE OF THE FRONT AND 0.2-0.3 OF PRECIP WITH IT CROSSING DURING
THE DAY ADDS TO THE UNCERTAINTY OF HOW MUCH SNOW ACCUMULATION WILL
OCCUR. MOST OF THE ACCUMULATION HAS BEEN LIMITED TO NORTH AND EAST
OF PITTSBURGH AT THIS TIME. HIGHS ON TUESDAY WILL MOSTLY BE REACH
BEFORE 18Z...AROUND 5 DEGREES ABOVE NORMAL WITH MANY LOWLAND
LOCATIONS WARMING TO AROUND 40.
TUESDAY NIGHT INTO WEDNESDAY...BEHIND THE FRONT...LOW-LEVEL FLOW
WILL SHIFT TO WESTERLY ON TUESDAY NIGHT AND AID UPSLOPING FOR THE
RIDGES. THIS WILL CONTINUE INTO EARLY ON WEDNESDAY. WITH INITIAL
SNOW WITH FRONTAL PASSAGE THEN UPSLOPING...ANTICIPATE COMBINED
TUESDAY INTO WEDNESDAY TOTALS OF 3 TO 6 INCHES FOR THE RIDGES AND
2 TO 5 NORTH OF PITTSBURGH AT THIS TIME. WITH STRONG CAA BEHIND
THE FRONT...TEMPS WILL BE AROUND 10 DEGREES BELOW NORMAL FOR LOWS
TUESDAY NIGHT AND HIGHS ON WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY NIGHT
WITH DRY CONDITIONS AND BELOW NORMAL TEMPERATURES INTO THURSDAY.
A DEEP TROUGH ACROSS THE WESTERN CONUS WILL CLOSE OFF INTO A LOW
ACROSS THE NORTHERN PLAINS THURSDAY NIGHT WITH AN OCCLUDING OR
OCCLUDED FRONTAL BOUNDARY APPROACHING THE UPPER OHIO VALLEY. THIS
FRONT WILL CROSS THE REGION LATER THURSDAY NIGHT AND FRIDAY. LIKELY
POPS AS THIS SYSTEM PASSES WITH SNOW TO A MIX THEN RAIN AS THE FRONT
PROGRESSES EASTWARD. REGION WILL THEN BE IN WEAK COLD ADVECTION
FRIDAY NIGHT INTO SATURDAY AS A SECONDARY COASTAL LOW MAY FORM OFF
OF NEW ENGLAND. SCATTERED RAIN AND SNOW SHOWERS WILL DIMINISH BY
LATE SATURDAY. HIGH PRESSURE WILL THEN RETURN FOR DRY AND SEASONABLE
CONDITIONS FOR SUNDAY.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
GENERAL MVFR FORECAST INTO LATE AFTERNOON WITH BRIEF IFR IN SNOW
SHOWERS. BY THIS EVENING SURFACE RIDGE ADVANCING EAST FROM OHIO WILL
GRADUALLY END SNOW SHOWERS AND EVENTUALLY CLEAR OUT SKIES FOR THE
OVERNIGHT. WINDS GUSTING OVER 20KTS FROM THE NORTHWEST INTO THE
EVENING WILL SUBSIDE TO LIGHT AND VARIABLE BETWEEN 02-05Z. ON MONDAY
SURFACE HIGH WILL SLIDE EAST WITH VFR AND A SOUTH WIND TO 10 KTS
DEVELOPING MID TO LATE MORNING.
.OUTLOOK.../SUNDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL BRING RESTRICTIONS IN MIXED PRECIPITATION LATER
MONDAY NIGHT AND TUESDAY. EXPECT RESTRICTIONS TO LINGER IN COLD
NORTHWEST FLOW BEHIND FRONT THROUGH WEDNESDAY. VFR THURSDAY UNDER
HIGH PRESSURE. RESTRICTIONS POSSIBLE IN MIXED PRECIPITATION FOR
FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
041.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
SHORT TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
122 PM EST SUN FEB 17 2013
.SYNOPSIS...
SNOW SHOWERS WILL DECREASE IN COVERAGE THIS EVENING. HIGH PRESSURE
WILL THEN BUILD IN TONIGHT WITH DRY AND WARMER WEATHER ARRIVING
ON MONDAY. A COLD FRONT WILL THEN RETURN RAIN AND SNOW TO THE AREA
ON TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT
FOR THE LATEST TRENDS IN RADAR AND SKY COVERAGE.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A MID-LEVEL TROUGH
AXIS CENTERED ACROSS EASTERN PA...LEAVING THE UPPER OHIO VALLEY IN
A NORTHWESTERLY FLOW IN THE WAKE OF THIS FEATURE. AT 850MB...A
NORTH-NORTHWESTERLY FLOW IS IN PLACE ACROSS THE LOWLANDS...WITH
MORE OF WESTERLY COMPONENT ACROSS THE LAUREL HIGHLANDS AND
ALLEGHENY FRONT OF WV/PA/MD. AT THE SURFACE...A LOW PRESSURE
SYSTEM IS OFF THE COAST OF NEW ENGLAND WITH A BROAD AREA OF HIGH
PRESSURE EXTENDING FROM THE UPPER MIDWEST TO THE GULF OF MEXICO.
THE COMBINATION OF WEAK VORT ENERGY SWINGING SOUTHEASTWARD ON THE
BACK END OF THE TROUGH ALONG WITH MOISTURE FILTERING IN FROM LAKE
HURON HAS ALLOWED SCATTERED SNOW SHOWERS TO CONTINUE ACROSS MUCH
OF THE AREA...WITH MORE WIDESPREAD SNOW SHOWERS WITH UPSLOPING
ACROSS THE RIDGES.
THIS AFTERNOON...THE UPPER TROUGH WILL PUSH OFF THE EAST COAST
WITH THE AREA REMAINING IN A NORTHWESTERLY FLOW AS HIGH PRESSURE
BEGINS TO BUILD IN FROM THE SOUTHWEST. VORT ENERGY SLIDING
EASTWARD WILL ALLOW FOR SNOW SHOWERS TO CONTINUE...BUT MOISTURE
WILL BECOME MORE SHALLOW WITH AN INVERSION LOWERING THIS
AFTERNOON...ALLOWING FOR SNOWFALL TO CONTINUE TO DECREASE IN
COVERAGE AND DIMINISH. UPSLOPING WILL ALLOW FOR ACCUMULATING
SNOWFALL TO CONTINUE IN THE EASTERN RIDGES...WITH AN ADDITIONAL 1
TO 2 INCHES THERE. WITH AMOUNTS ALREADY REPORTED AS HIGH AS 7
INCHES NEAR SEVEN SPRINGS...HAVE DECIDED TO MENTION ISOLATED 7 TO
10 STORM TOTAL AMOUNTS FOR THE HIGHEST ELEVATIONS...PARTICULARLY
OF WESTMORELAND AND FAYETTE COUNTIES.
TEMPS WILL ONLY INCREASE A FEW DEGREES TODAY...WITH HIGHS NEAR
LAMP GUIDANCE...RANGING FROM THE MID TEENS ACROSS THE EASTERN
RIDGES TO THE MID 20S SOUTH AND WEST OF PITTSBURGH. WITH A
TIGHTENED PRESSURE GRADIENT SETUP BETWEEN THE COASTAL LOW AND HIGH
APPROACHING FROM THE SOUTHWEST...WINDS OF 10 TO 15 MPH ARE
FORECAST WITH GUSTS TO 25 MPH FOR THE LOWLANDS AND 35 MPH FOR THE
RIDGES. THIS WILL LEAD TO WIND CHILLS BELOW 0 FOR THE RIDGES.
TONIGHT...HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST WITH AN
850MB RIDGE MOVING INTO THE AREA AND BRINGING AN END TO LINGERING
UPSLOPING SNOWS FOR THE RIDGES. SKIES WILL CLEAR OUT WITH WINDS
DECREASING TO AROUND 5 MPH. WITH 850MB TEMPS AS COLD AS
16C...ALONG WITH CLEARING AND DECREASED WINDS CONTRIBUTING TO SOME
RADIATIONAL COOLING...LOWS TONIGHT WILL RANGE FROM THE SINGLE
DIGITS ACROSS THE HIGHER ELEVATIONS TO THE MID TEENS ACROSS THE
LOWLANDS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
SOUTHERLY WINDS ON MONDAY ALONG WITH MOSTLY SUNNY SKIES WILL BRING A
MUCH WARMER DAY. COLD FRONT THAT WILL CROSS THE REGION MONDAY NIGHT
AND TUESDAY APPEARS TO BE MOVING SLIGHTLY SLOWER...AND HAVE DELAYED
FRONTAL PASSAGE BY A FEW HOURS. NO CHANGE TO CATEGORICAL POPS IN THE
FORECAST. HAVE REMOVED MENTION OF FREEZING PRECIPITATION WITH MODELS
NOT SHOWING MUCH OF A WARM TONGUE ALOFT. HOWEVER...WITH LOWS MONDAY
NIGHT EXPECTED TO BE IN THE MID 30S...TEMPERATURES WILL BE MARGINAL
FOR SNOW. A CHANGE IN THE TEMPERATURE FORECAST BY JUST A COUPLE OF
DEGREES COULD HAVE SIGNIFICANT IMPACTS TO THE PRECIPITATION TYPE
FORECAST AND POSSIBLE SNOWFALL ACCUMULATION. WITH THIS FORECAST
UPDATE...HAVE ADDED SOME LIGHT SNOW ACCUMULATIONS...GENERALLY NORTH
OF PITTSBURGH. NEARLY ALL LOCATIONS WILL SEE AT LEAST SOME RAIN ON
TUESDAY MORNING...WITH PRECIPITATION CHANGING OVER TO SNOW DURING
THE AFTERNOON HOURS BEHIND THE COLD FRONT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AN ECMWF/GFS/CANADIAN BLEND INDICATES A CLOSED UPPER LEVEL VORTEX
CENTERED ACROSS THE NORTHERN GREAT LAKES WITH THE COLD FRONT
SHIFTING EAST OF THE AREA TUESDAY NIGHT. LINGERING SNOW SHOWERS ON
THE BACK SIDE OF THE FRONT WILL BE MOSTLY DIMINISHING TUESDAY
NIGHT. THE CHC OF SNOW SHOWERS WILL LINGER INTO WEDNESDAY FOR THE
HIGHER ELEVATIONS WITH UPSLOPING FAVORED BY A WESTERLY FLOW
VEERING TO WEST-NWRLY.
A GFSE/NAEFS MODEL CONSENSUS INDICATES A MID-LEVEL RIDGE AND SURFACE
HIGH SHIFTING PUSHING INTO THE UPPER OHIO VALLEY WEDNESDAY NIGHT
INTO THURSDAY WITH A DRY FORECAST IN PLACE.
A DEEP TROUGH ACROSS THE WESTERN CONUS WILL CLOSE OFF INTO A LOW
ACROSS THE NORTHERN PLAINS THURSDAY NIGHT. THE LOW WILL SWING A
FRONTAL BOUNDARY NORTHEASTWARD INTO THE UPPER OHIO VALLEY THROUGH
THE DAY FRIDAY. GFS/ECMWF ARE INDICATING THE 1000-850MB 1300M
THICKNESS LINE SLIPPING NORTHWARD ACROSS WESTERN PA ON FRIDAY. WITH
A WARMER WEDGE OF AIR ADVECTING INTO THE AREA AND CREATING A
MELTING LAYER ALOFT...THERE IS THE POTENTIAL FOR A WINTRY MIX EVENT
ACROSS THE AREA EARLY ON FRIDAY. GIVEN THAT THIS IS A DAY 6
FORECAST...THERE IS STILL QUITE A BIT OF UNCERTAINTY WITH HOW THE
THERMAL PROFILE AND AVAILABLE MOISTURE WILL SETUP WITH THIS
EVENT...SO HAVE GONE WITH A MIX OF RAIN AND SNOW AT THIS TIME.
HOWEVER...MODEL SOUNDINGS ARE HINTING AT THE POTENTIAL FOR
SLEET/FZRA AT THE ONSET OF PRECIP. THUS...THIS POTENTIAL EVENT WILL
NEED TO BE MONITORED IN THE COMING DAYS.
MODELS DIVERGE FRIDAY NIGHT INTO SATURDAY AND THUS DO NOT WAVER FAR
FROM HPC FORECAST WITH SCHC POPS FOR THE END OF THE FORECAST PERIOD.
TEMPS WILL BE AROUND 10 DEGREES BELOW NORMAL BEHIND THE FRONT ON
WEDNESDAY AND THEN MODERATE EACH DAY TO NEAR NORMAL SEASONAL VALUES
FRIDAY INTO SATURDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
GENERAL MVFR FORECAST INTO MID AFTERNOON WITH BRIEF IFR IN SNOW
SHOWERS. BY THIS EVENING SURFACE RIDGE WILL BRING AN END TO SNOW
SHOWERS AND GRADUALLY CLEAR OUT SKIES FOR THE OVERNIGHT. WINDS
GUSTING OVER 20KTS FROM THE NORTHWEST INTO THE EVENING WILL SUBSIDE
TO LIGHT AND VARIABLE BETWEEN 02-05Z. ON MONDAY SURFACE HIGH WILL
SLIDE EAST WITH VFR AND A SOUTH WIND TO 10 KTS DEVELOPING MID
MORNING.
.OUTLOOK.../SUNDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL BRING RESTRICTIONS IN RAIN OR SNOW LATER MONDAY
NIGHT AND TUESDAY. EXPECT RESTRICTIONS LINGER IN COLD NWRLY FLOW
BEHIND FRONT THROUGH WEDNESDAY. VFR THURSDAY UNDER HIGH PRESSURE.
RESTRICTIONS POSSIBLE IN MIXED PRECIPITATION FOR FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ074-076.
WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
WVZ023-041.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1241 PM EST SUN FEB 17 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 514 AM EST SUN FEB 17 2013
WV IMAGERY AND RUC ANALYSIS INDICATED NNW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A TROUGH INTO THE ERN LAKES AND
A RIDGE OVER THE NRN PLAINS INTO MANITOBA. UPSTREAM ANOTHER THROUGH
AND VIGOROUS SHRTWV WAS MOVING THROUGH THE NRN ROCKIES. AT THE
SFC...A RIDGE EXTENDED FROM W OF JAMES BAY INTO UPPER MI AND WI.
WITH VERY LIGHT SYNOPTIC SCALE WINDS...LAKE INDUCED TROUGHING AND
WIND FIELDS DOMINATED LAKE SUPERIOR. LAND BREEZES ALONG WITH A WEAK
NRLY GRADIENT FLOW HAS RESULTING IN STRONGEST AREA OF LOW LEVEL CONV
OVER E CNTRL LAKE SUPERIOR FOCUSING LES INTO THE PICTURED ROCKS AND
FAR NRN SCHOOLCRAFT COUNTY. HOWEVER...SNOW INTENSITY HAS
DIMINISHED...PER RADAR REFLECTIVITY TRENDS. UPSTREAM...CLOUDS WERE
THICKENING ACROSS MN WITH WAA PATTERN AHEAD OF A TROUGH FROM SRN
SASK INTO ERN MT.
AS THE HIGH SHIFTS TO THE EAST...WINDS OVER ERN LAKE SUPERIOR WILL
FINALLY BECOME SRLY...PUSHING ANY REMAINING LES OFFSHORE. ADDITIONAL
ACCUMULATIONS AROUND AN INCH MAY BE POSSIBLE NEAR THE SHORE FROM
PICTURED ROCKS TO GRAND MARAIS. WAA WITH INCREASING SRLY WINDS AND
SUNSHINE DURING MUCH OF THE DAY WILL HELP TEMPS RECOVER QUICKLY FROM
THE FRIGID START WITH MAX READINGS CLOSER TO SEASONAL
AVERAGES...FROM AROUND 20 CNTRL TO 25 WEST.
NAM/GFS 280K-295K ISENTROPIC PROGS AND SATELLITE TRENDS SUGGEST THAT
CLOUDS WILL MOVE IN LATE TODAY AND THICKEN ACROSS THE AREA THIS
EVENING. THE STRONGEST ASCENT AND BEST CHANCE TO SATURATE THE LOWER
LEVELS IN THE VERY DRY ANTECEDENT AIRMASS WILL BE ACROSS LAKE
SUPERIOR AND THE TIP OF THE KEWEENAW. TO THE SOUTH...A LARGE PORTION
OF ANY PCPN MAY EVAPORATE BEFORE REACHING THE SFC. SO...A QPF
PATTERN MORE IN LINE WITH THE NAM WAS FAVORED. ONLY CHANCE POPS WERE
INCLUDED WITH MINIMAL IF ANY SNOW ACCUMULATIONS LESS THAN A HALF
INCH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 514 AM EST SUN FEB 17 2013
ACTIVE WINTER PATTERN CONTINUES THROUGH THE UPCOMING WEEK. A COUPLE
SHOTS AT WIDESPREAD SYNOPTIC SNOWFALL...FIRST ON MONDAY/MONDAY NIGHT
THEN AGAIN ON FRIDAY. BETWEEN THESE SYSTEMS...ROBUST NNW-NW FLOW
LAKE EFFECT EVENT AFFECTS NORTHERN HALF OF UPR MICHIGAN TUESDAY INTO
WEDNESDAY. AFTER ABOVE NORMAL TEMPERATURES ON MONDAY IN SOUTHERLY
FLOW AHEAD OF LOW PRESSURE...TEMPERATURES MOST OF THE WEEK WILL BE
AT OR BLO NORMAL. COLDEST TIME APPEARS TO BE TUESDAY INTO WEDNESDAY.
TEMPERATURES REBOUND TO AROUND NORMAL TO CLOSE THE WEEK.
FIRST ISSUE IS LGT SNOW ON MONDAY AS UPR TROUGH AND DEEPENING
SFC-H85 LOWS MOVE TOWARD UPR LAKES FROM SCNTRL CANADA. WARM AIR
ADVECTION BATCH OF LGT SNOW SHOULD BE ONGOING TO START THE DAY
ACROSS LAKE SUPERIOR AND FAR NORTHERN CWA. INDICATIONS ARE THAT MOST
OF THIS SNOW WILL BE DIMINISHING THROUGH THE MORNING...LEAVING A
LULL OVER MUCH OF CWA UNTIL THE AFTN. AFT 18Z...SOUNDINGS INDICATE
DEEP MOISTENING FROM ABOVE H8 AS SFC-H85 LOWS DEEPEN WHILE MOVING
INTO WESTERN HALF OF UPR MICHIGAN. AT THIS POINT IS WHERE MODELS
DIVERGE IN HANDLING TRACK OF SFC LOW. GFS/ECMWF STAYING CONSISTENT
WITH SFC LOW MOVING INTO SOUTH CNTRL UPR MICHIGAN BY 00Z TUESDAY AND
MOVING JUST EAST OF UPR MICHIGAN BY 12Z TUESDAY. GEM-NH/UKMET SLOWER
AND FARTHER WEST WITH THE SFC LOW AS THEY SHOW IT OVER NORTHERN LK
MICHIGAN/STRAITS BY 12Z TUESDAY. ONLY A SUBTLE DIFFERENCE BUT IT IS
RESULT OF DEEPER/CLOSED OFF UPR TROUGH. A DEEPER SYSTEM WOULD RESULT
IN LGT-MODERATE SYNOPTIC SNOW OVER EAST HALF OF CWA THROUGH MOST OF
MONDAY NIGHT COMPARED TO GFS/ECMWF. MORE MOISTURE IS ALSO BROUGHT
INTO SYSTEM MONDAY AFTN/EVENING...SO ULTIMATELY SNOW AMOUNTS WOULD
BE CLOSE TO ADVY LEVELS. NOT GOING THAT WAY NOW...THOUGH WILL ADMIT
THE GEM-NH CONSISTENCY IS A BIT CONCERNING. EVEN SO...PRIMARY
WEST-EAST JET ENERGY STAYS LOCKED INTO SOUTHERN STREAM OF THE UPPER
TROUGH WHICH SUPPORTS GOING WITH MORE PROGRESSIVE UPR TROUGH AND A
FARTHER EAST SFC LOW TRACK. UPSHOT...A FEW INCHES OF SNOW IN THE
EAST WITH JUST AN INCH OR TWO ELSEWHERE OVR CWA. SNOW WILL BE A
WETTER TYPE SNOW...NOT THE REALLY FLUFFY VARIETY THAT HAS BEEN WITH
US LATELY.
DEEPENING UPPER TROUGH SWINGS ACROSS GREAT LAKES ON TUESDAY HELPING
TO DRAW IN MUCH COLDER AIR YET AGAIN. H85 TEMPS AT 06Z TUESDAY ONLY
AS COLD AS AROUND -13C OVR LK SUPERIOR BUT BY 18Z TUESDAY ARE
ALREADY DOWN BLO -20C. ALL THE WHILE...SINCE UPR TROUGH IS DEEPENING
OVR THE AREA...THERE IS PLENTY OF DEEPER MOISTURE PRESENT WITH
STRONG CYCLONIC N-NW FLOW. KIND OF A PSUEDO LAKE ENHANCED SETUP
THOUGH THERE DOES NOT LOOK TO BE MUCH LARGE SCALE LIFT GOING ON.
SLR/S IN THEORY SHOULD END UP OVR 30:1 BUT GIVEN STRONG WINDS OVR 30
KTS IN THE BLYR...EXPECT FRACTURING TO HOLD SLR/S DOWN TO AN AVERAGE
OF 25-30:1. FIRST PASS AT SNOW AMOUNTS INDICATES HIGH-END ADVY BUT
SIMILAR TO LAST EVENT...LONG DURATION OF THE SNOW MAY RESULT IN SNOW
TOTALS FROM LATE MONDAY NIGHT THROUGH TUESDAY NIGHT AND WEDNESDAY
OVER A FOOT IN SOME LOCATIONS. FAVORED LOCATIONS WITH EXPECTED NNW
WINDS WOULD BE MUCH OF HIGHER TERRAIN OF ONTONAGON COUNTY THROUGH
TWIN LAKES...HIGHER TERRAIN OF BARAGA AND NORTHERN MARQUETTE
COUNTY...THEN EVENTUALLY THE SNOWBELTS OVER OF THE EASTERN CWA LATER
TUESDAY THROUGH WEDNESDAY. UNLIKE RECENT LAKE SNOW EVENT...WIND/BLSN
WILL BE BIGGER ISSUE WITH WELL MIXED BLYR. EXPECT WIDESPREAD BLSN
AND REDUCED VSBY ALONG WITH MODERATE TO HEAVY SNOW SHOWERS.
SINCE WE STILL HAVE TO GET THROUGH THE WIDESPREAD SYNOPTIC LGT SNOW
MONDAY AND MONDAY EVENING AND THIS IS MAINLY A 5TH PERIOD AND BEYOND
EVENT DID NOT ISSUE ANY HEADLINES AT THIS POINT. WILL MENTION IN HWO
AND HIT UP THE BLSN AS WELL. SEEMS THAT TRAVEL MAY BE DIFFICULT NEAR
MUCH OF LK SUPERIOR TUESDAY INTO TUESDAY EVENING.
REST OF LONG TERM...LK EFFECT DIMINISHES STEADILY ON WEDNESDAY FROM
WEST TO EAST AS UPR TROUGH/DEEPER MOISTURE EXITS TO EAST. LEFT OVER
LAKE EFFECT WILL BE PLAGUED BY LOWERING INVERSION AND DIMINISHING
CYCLONIC FLOW. WEAKER LK EFFECT AND/OR FLURRIES HANG ON THROUGH
THURSDAY OVER NCNTRL CWA WITH WINDS BECOMING N/NE. DRY ELSEWHERE AS
WE AWAIT SYSTEM THAT WILL BE BRINGING SNOW TO PARTS OF NORTHERN
PLAINS AND MO RIVER VALLEY ON THURSDAY. GFS/ECMWF IN VERY GOOD
AGREEMENT THAT SFC LOW LIFTS TOWARD UPR MISSISSIPPI RIVER VALLEY BY
DAYBREAK FRIDAY AND WEAKENS WHILE MOVING INTO UPR LAKES LATE FRIDAY.
SWATH OF LGT SNOW COMES IN FROM SOUTHWEST LATE THURSDAY NIGHT AND A
GENERAL DECAYING TREND TO SNOW CONTINUES ON FRIDAY...THOUGH AT LEAST
LGT ACCUMS WILL AFFECT MUCH OF UPR MICHIGAN ON FRIDAY. POPS HIGH
CHANCE FOR NOW BUT IF MODELS REMAIN IN GOOD AGREEMENT COULD
EVENTUALLY SEE NEED FOR LIKELY POPS THU NIGHT INTO FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM EST SUN FEB 17 2013
EXPECT VFR CONDITIONS TO DECREASE TONIGHT AS A LOW PRESSURE SYSTEM
MOVES IN FROM THE WEST. LLWS IS POSSIBLE TONIGHT AT ALL SITES WITH
STRONG SOUTHERLY FLOW AHEAD OF THE LOW PRESSURE SYSTEM...BUT THINK
IT WILL BE GUSTY ENOUGH TO KEEP LLWS OUT OF THE TAF. MAIN WEATHER
THIS TAF PERIOD IS SOME LIGHT SNOW AT CMX TONIGHT...AND FREEZING
DRIZZLE AT SAW DUE TO UPSLOPE SE WINDS...AMPLE LOW LEVEL MOISTURE
AND NO MOISTURE IN THE ICE PRODUCING LATER ALOFT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 514 AM EST SUN FEB 17 2013
AS HIGH PRES SHIFTS TO THE EAST...A LOW PRESSURE SYSTEM WILL
APPROACH THE UPPER GREAT LAKES ON MONDAY AND MOVE THROUGH ON
TUESDAY. THIS WILL BRING INCREASING SOUTHERLY WINDS ON MONDAY...TO
30 KTS OVER THE EAST...AND THEN STRONG NORTHERLY GALES BEHIND THE
LOW ON TUESDAY AND TUESDAY NIGHT...TO 45 KTS. THERE COULD BE A FEW
GALE FORCE GUSTS TO 35 KNOTS ON MONDAY OVER EASTERN LAKE SUPERIOR.
WITH THE HIGHER WINDS AND COLDER AIR TUESDAY INTO WEDNESDAY...HEAVY
FREEZING SPRAY IS ALSO EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR
LSZ245>251-265>267.
GALE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR
LSZ162.
GALE WATCH FROM LATE MONDAY NIGHT THROUGH WEDNESDAY AFTERNOON
FOR LSZ240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
319 PM CST SUN FEB 17 2013
.SHORT TERM...
MAIN CHALLENGE FOR THIS PORTION OF THE FORECAST WILL BE HOW TO
HANDLE HEADLINES WITH THE LOW CROSSING THE AREA TONIGHT INTO
MONDAY. MODELS STILL HAVE SOME SUBTLE DIFFERENCES IN REGARD TO
SNOWFALL AMOUNTS TONIGHT BUT GUSTY WIND LOOKS LIKE A SURE BET.
TONIGHT...SFC LOW IS CURRENTLY OVER NORTH CENTRAL/NORTHEAST ND
WITH VERY MILD AIR ASSOCIATED WITH IT. GETTING A SOUTHWEST SFC
COMPONENT TO THE WINDS OVER THE FAR WESTERN FA WHERE TEMPS HAVE
CLIMBED INTO THE LOW TO MID 30S. OTHER AREAS WILL PROBABLY SEE
SOME LATE AFTERNOON OR EARLY EVENING RISE BEFORE FALLING LATE.
STIFF SOUTH WINDS ARE CAUSING SOME DRIFTING SNOW ACROSS SOME ROADS
AND WITH THE MILD ROAD TEMPS ARE MELTING AND THEN REFREEZING.
OTHERWISE THE WARM TEMPS SHOULD BE GIVING A BIT OF A CRUST TO THE
SNOW IN THOSE AREAS ABOVE 32F. RADAR STILL SHOWING SOME ECHOES
ACROSS THE EAST BUT ONLY KBDE/KFGN ARE STILL REPORTING SOME LIGHT
SNOW. NOT REALLY EXPECTING SNOW ACROSS THE SOUTHERN FA PRIOR TO
MIDNIGHT. THERE SHOULD BE IN THE NORTH THOUGH WITH BEST CHANCES
ALONG THE CANADIAN BORDER. NEW 18Z NAM HAS COME IN SHOWING A BAND
DEVELOPING ACROSS THE CENTRAL RED RIVER VALLEY IN THE EVENING
WHICH LOOKS A LITTLE ODD. THE 12Z GFS SHOWS A BAND DEVELOPING
ACROSS CENTRAL ND AND LIFTING INTO THE NORTHERN RED RIVER VALLEY.
ECMWF SEEMS PRETTY CONSISTENT IN HITTING NORTHEAST ND INTO
PORTIONS OF NORTHWEST MN OR AREAS MAINLY NORTH OF HIGHWAY 2 WITH
THE MOST SNOW. THEREFORE WILL STICK WITH THE IDEA OF 3 TO 6 INCHES
ACROSS THIS AREA TAPERING TO LITTLE OR NOTHING ACROSS THE FAR
SOUTH. WIND SPEEDS WILL NOT KICK IN UNTIL LATE TONIGHT. GENERALLY
EXPECTING THIS AFTER MIDNIGHT IN THE FAR NORTH AND AROUND 09Z MON
IN THE KGFK AREA. STRONG WINDS SHOULD NOT HIT THE KFAR AREA DOWN
TO WAHPETON UNTIL 12Z OR LATER. WITH SNOW AND WIND POTENTIAL WILL
ISSUE BLIZZARD WARNINGS FOR NORTHEAST ND INTO THE RED RIVER VALLEY
COUNTIES OF EXTREME NORTHWEST MN STARTING AFTER MIDNIGHT. WITH THE
SNOWFALL UNCERTAINTIES WILL LEAVE THE VALLEY CITY TO FARGO TO ADA
AREA IN THE BLIZZARD WATCH YET. WILL COVER THE FAR SOUTH WITH A
WINTER WEATHER ADVISORY WHICH WILL HAVE TO BE MONITORED IF THE
SNOW MAKES IT FURTHER SOUTH. WENT WITH WINTER STORM WARNING FOR
THE ROSEAU TO KTVF AREA AND LAKE OF THE WOODS AREA FOR 4 TO 6
INCHES OF SNOW WITH GUSTY WINDS. WILL LEAVE THE MAHNOMEN TO KBJI
AREA IN A WINTER STORM WATCH DUE THE UNCERTAINTY WITH SNOWFALL
YET.
MON-WED...WINDS SHOULD BE GOING PRETTY WELL BY SUNRISE AND SHOULD
CONTINUE HOWLING THROUGH THE DAY. LEFT ALL HEADLINES IN EFFECT
THROUGH 00Z TUE EXCEPT THE WINTER WEATHER ADVISORY AREA...WHICH
GOES UNTIL 03Z TUE. OTHER AREAS MAY NEED SOME EXTENDING OR
TWEAKING BUT LATER SHIFTS CAN ALWAYS DO THIS. SFC HIGH BUILDS IN
ON TUE AND SHOULD KEEP THINGS CLEAR THRU MOST OF WED. THIS WILL
SET THE STAGE FOR SOME COLD DAYS AND NIGHTS AND THE POTENTIAL FOR
SOME WIND CHILL ISSUES WHICH WILL NEED TO BE ADDRESSED LATER.
.LONG TERM (THU-SUN)...
MAIN ISSUE REVOLVE AROUND THE NORTHWARD EXTENT OF PRECIPITATION FROM
THE CENTRAL PLAINS STORM. GEM/GFS/EURO ALL BRING SFC LOW INTO
KANSAS THURSDAY THEN MOVE IT NORTHEAST AND WEAKEN WITH WITH TIME
WHILE A LARGE UPPER LOW FORMS IN NEBRASKA AND DRIFTS NORTH INTO THE
EASTERN DAKOTAS FRI. MODEL DIFFERENCES CONCERN THE AMOUNT OF PRECIP
THAT WILL SPREAD NORTH AS STORM WEAKENS...WITH 00Z-12Z ECMWF STILL A
BIT MORE WET THAN GFS AND ESP THE GEM. THAT SAID WILL CONTINUE WITH
GENERAL MODEL BLEND FORECAST OF LIKELY POPS OR HIGH CHANCE IN THE
SOUTH THURSDAY NIGHT INTO FRIDAY...WITH LOWER POPS NORTH. ALL
MODELS KEEP UPPER LOW AROUND SAT-SUN WITH SOME CHANCES FOR VERY
LIGHT SNOW.
&&
.AVIATION...
LOWER CLDS HAVE CLEARED OUT OF ALL THE FCST AREA THIS AFTN LEAVING A
VFR CLOUD DECK IN THE MINNESOTA AND A MORE CIRRUS DECK IN ERN ND.
SOUTH WINDS REMAIN GUSTY TO 25 KTS IN THE RED RIVER VALLEY BUT ARE
TENDING TO SLOWLY DIMINISH AND WILL LOOK FOR THE WIND TO CONTINUE TO
DIMINISH SLOWLY THROUGH EARLY EVENING AS SFC LOW IN SOUTHEAST SASK
MOVES CLOSER. FOCUS TONIGHT INTO MONDAY WILL BE TIMING OF WIND
SHIFT AND THEN VSBY/CIGS WITH SNOW EXPECTED ESP DVL-GFK-TVF
REGIONS. BASED WIND CHANGE AND SNOW TIMING ON RAP MODEL WITH STRONG
WINDS NOT HITTING TIL A FEW HOURS AFTER FRONTAL PASSAGE. VSBYS AND
CIGS MONDAY MAY BE QUITE VARIABLE BUT GENERALLY IFR DVL-GFK-TVF IN
BLSN...FARGO-BJI A MIX OF MVFR AND IFR MAINLY DUE TO VSBYS. WINDS
IN THE RED RIVER VALLEY AND DVL REGION WILL GUST TO 40 KTS OR HIGHER
AT TIMES MONDAY WITH 25 TO 30 KTS PSBL MON AFTN IN BEMIDJI.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY FROM 6 AM TO 9 PM CST MONDAY FOR NDZ049-
052-053.
BLIZZARD WARNING FROM 3 AM TO 6 PM CST MONDAY FOR NDZ016-024-
026>030.
BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 PM CST MONDAY FOR
NDZ006>008-014-015-054.
BLIZZARD WATCH FROM MONDAY MORNING THROUGH MONDAY AFTERNOON FOR
NDZ038-039.
MN...WINTER WEATHER ADVISORY FROM 6 AM TO 9 PM CST MONDAY FOR MNZ027-
029>031-040.
WINTER STORM WATCH FROM MIDNIGHT CST TONIGHT THROUGH MONDAY
AFTERNOON FOR MNZ015>017-022.
BLIZZARD WARNING FROM 3 AM TO 6 PM CST MONDAY FOR MNZ001-004-007.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM CST MONDAY
FOR MNZ005-006-008-009-013-014.
BLIZZARD WATCH FROM MONDAY MORNING THROUGH MONDAY AFTERNOON FOR
MNZ002-003.
&&
$$
GODON/RIDDLE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1246 PM EST SUN FEB 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE AREA TODAY. AS IT PUSHES OFF TO
THE EAST THROUGH THE DAY ON MONDAY...INCREASING SOUTHERLY WINDS
WILL PULL WARMER AIR INTO THE REGION. RAIN WILL OVERSPREAD THE
AREA MONDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED THE FORECAST TO ACCOUNT FOR PESKY BANDS OF LOW CLOUDS AND
FLURRIES ACROSS WCNTL/CNTL OHIO. 17.12Z KILN SOUNDING WAS QUITE
DRY /PWAT 0.09 INCH/ SUGGESTING MOISTURE IS VERY THIN/SHALLOW BUT
GIVEN VERY COLD THICKNESSES AND NWLY LOW LEVEL FLOW THERE IS STILL
ENOUGH TO WRING OUT A LITTLE -SN ACTIVITY. WITH RAP 900MB FLOW
STILL NNWLY THROUGH MIDDAY EXPECT CLOUDS TO BUILD/DEVELOP SLOWLY
SOUTHEAST THROUGH REMAINDER OF CNTL INTO SCNTL OHIO THROUGH EARLY
AFTERNOON...AND MAY NEED TO UPDATE FORECAST TO BE A LITTLE MORE
BULLISH ON CLOUD COVER IN COMPARISON TO THIS UPDATE. WITH 925MB
TEMPS STILL -14C...AND FLOW NOT EXPECTED TO BACK AROUND TO W/SW
UNTIL MID AFTN...HAVE DROPPED FCST MAX TEMPS A DEGREE OR TWO ALL
AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
HIGH PRESSURE WILL SLIDE EAST OF THE AREA TONIGHT WITH RETURN FLOW
SETTING UP FOR MONDAY AHEAD OF AN APPROACHING COLD FRONT. GOOD WAA
WILL DEVELOP THROUGH THE DAY ON MONDAY AS A 40-50 KNOT 925 JET WORKS
IN FROM THE WEST THROUGH THE AFTERNOON. THIS WILL HELP PUSH
TEMPERATURES WELL ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER
40S NORTH TO LOWER/MID 50S ACROSS THE SOUTH.
IN A DEVELOPING ISENTROPIC FLOW PATTERN...A FEW SHOWERS COULD
SNEAK INTO OUR WEST LATE IN THE DAY. HOWEVER...BULK OF PCPN SHOULD
HOLD OFF UNTIL MONDAY EVENING WHEN IT OVERSPREADS OUR AREA FROM
THE WEST AND THEN CONTINUES THROUGH THE OVERNIGHT HOURS. THE COLD
FRONT WILL PUSH IN FROM THE WEST LATE MONDAY NIGHT. THIS WILL
ALLOW FOR TEMPERATURES TO DROP OFF QUICKLY ACROSS THE WEST
LATE...WITH RAIN STARTING TO MIX WITH/CHANGE TO SNOW. GOOD CAA
WILL OVERSPREAD THE AREA THROUGH TUESDAY MORNING WITH ANY
LINGERING RAIN CHANGING OVER TO ALL SNOW. AS DRIER AIR MOVES IN
FROM THE WEST...PCPN SHOULD TAPER OFF TO A FEW SHOWERS HEADING
THROUGH THE REST OF THE DAY. EXPECT ANY SNOW ACCUMULATIONS TO BE ON
THE LIGHT SIDE AS MORE SIGNIFICANT PCPN SHOULD BE ENDING AS
THE COLDER AIR WORKS IN. GIVEN THE GOOD CAA ON TUESDAY...DO NOT
EXPECT MUCH TEMPERATURE RECOVERY...WITH EARLY HIGHS LIKELY ACROSS
THE EAST WITH TEMPERATURES THEN FALLING OFF THROUGH THE REST OF
THE DAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE BUILDS DOWN INTO THE LOWER OHIO VALLEY TUE NIGHT
INTO WED BEFORE LIFTING NE ACROSS THE FA WED NGT. THIS SHOULD
PROVIDE DRY CONDITIONS FOR THE PERIOD...WITH NRN SECTIONS SEEING
MORE CLOUDS THAN THE S TUE NGT AND WED...BEFORE MOSTLY CLEAR SKIES
PREVAIL WED NGT.
SYSTEM DIGS INTO THE SRN ROCKIES WED NGT...THEN EJECTS OUT THU
INTO THU NGT. MODELS ARE SHOWING THEIR TYPICAL SPREAD. THE CMC IS
THE QUICKEST THIS RUN IN BRINGING RETURN PCPN TO THE FA THU AFTN.
THE 12Z RUNS OF THE GFS AND ECMWF ARE SLOWER...LIMITING POPS TO
THE SW. THICKNESSES WILL BE COLD ENUF FOR SOME RAIN/SNOW AT THE
ONSET. AS THE CENTER OF THE SYSTEM LIFTS OUT THRU THE PLAINS...AN
AREA OF PCPN WILL BE PUSHED ACROSS THE FA THU NGT INTO FRI. PCPN
WILL EITHER BE SN OR RA/SN MIX UNTIL A WRMFNT GRADUALLY BRINGS IN
WARMER AIR CHANGING THE PCPN TO RA BEFORE IT ENDS ON FRIDAY. HIGH
PRESSURE THEN BUILDS IN FOR FRIDAY.
COLD AIR WILL WORK IN TUESDAY NIGHT DROPPING TEMPERATURES IN THE
TEENS AND LOWER 20S. THE COOL NLY FLOW ON WED WILL KEEP TEMPS DOWN
IN THE UPPER 20S N TO THE MID 30S NRN KY. THE CLEAR SKIES WILL
ALLOW TEMPERATURES TO DROP BACK INTO THE TEENS AND LOWER 20S
AGAIN. ONLY EXPECT HIGHS ON THU TO MAKE THE 30S AHEAD OF THE STORM
SYSTEM...BUT WITH RISING TEMPS THU NGT. HIGHS FRIDAY SHOULD MAKE
THE 40S AS THE REGION GETS WARM SECTORED.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
PRIMARY BAND OF MVFR CIGS WITH -SN HAS BEEN THROUGH DAY/CMH THIS
MORNING AND NOW INDICATIONS THAT THIS IS BEGINNING TO BREAK UP AS
LOW LEVEL FLOW IS STARTING TO BACK MORE SUBSTANTIALLY NOW.
NUMEROUS OTHER CELLULAR CUMULUS NOW POPPING AROUND THAT MAIN BAND
AND MAY AFFECT ALL TERMINALS WITH A BRIEF MVFR/VFR CIG THIS
AFTN...BUT FOR THE MOST PART EXPECT SCT CUMULUS TO REMAIN NORTH OF
CVG/LUK...AFFECTING DAY/ILN AND OF COURSE LCK/CMH WHERE CLOUDS
REMAIN THE THICKEST. AS RIDGE AXIS COMES ACROSS THE SITES LATE
THIS AFTN/EVE...WINDS SHOULD BECOME VARIABLE/LIGHT ALL SITES AND
THEN IMMEDIATELY INCREASE FROM SOUTHEAST AFT 03Z OR SO. MORE
SUBSTANTIAL DECREASE IN CUMULUS SHOULD ALSO OCCUR DURING THIS TIME. LIGHT
SELY FLOW EXPECTED OVERNIGHT WITH MORE SUBSTANTIAL STRENGTHENING
/WITH GUSTS/ EXPECTED ON MONDAY AS FLOW BECOMES MORE SLY. DO
EXPECT A BAND OF WARM ADVECTION VFR CIGS TO SPREAD ACROSS THE
SITES AFTER 07Z AND THEN EXIT MOST AREAS BY 15Z AS MUCH WARMER AIR
STREAMS IN ALOFT. NEXT CYCLE OF CVG TAFS WILL NEED TO ADDRESS RAIN
MOVING INTO THAT AREA IN THE 24-30 HOUR FORECAST.
OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE MONDAY NIGHT AND EARLY
TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JGL
NEAR TERM...BINAU
SHORT TERM...JGL
LONG TERM...SITES
AVIATION...BINAU
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1150 AM CST SUN FEB 17 2013
.DISCUSSION.../ISSUED AT 1015 AM CST/
SURFACE LOW PRESSURE MOVING ACROSS THE CANADIAN BORDER WILL PUSH A
COLD FRONT THROUGH THE AREA TONIGHT. TODAY WILL BE A MILD AND BREEZY
DAY OUT AHEAD OF THIS FRONT. STILL EXPECTING SOUTHERLY WINDS TO
CONTINUE TO INCREASE THIS AFTERNOON...WITH GUSTS AROUND 30
MPH...ESPECIALLY ALONG AND EAST OF INTERSTATE 29. SEEING A BIT MORE
CIRRUS THAN FORECAST..SO WENT AHEAD AND UPPED CLOUD COVER...HOWEVER
SHOULD STILL SEE PARTLY SUNNY SKIES. CIRRUS PROBABLY WONT HAVE TOO
MUCH OF AN IMPACT ON HIGHS...ESPECIALLY SINCE A THINNER AREA SHOULD
BE OVER THE CWA FOR THE NEXT SEVERAL HOURS. GOING HIGHS LOOK IN
PRETTY GOOD SHAPE...ALTHOUGH DID GO AHEAD AND RAISE HIGHS A COUPLE
DEGREES IN OUR SOUTH BASED ON LATEST RAP AND HRRR TRENDS. /CHENARD
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS WILL CONTINUE THROUGH THE DAY. WINDS WILL BE BREEZY
THROUGH THIS AFTERNOON OUT OF THE SOUTH...WITH GUSTS AROUND 25
KTS...ESPECIALLY ALONG AND EAST OF INTERSTATE 29. COLD FRONT WILL
MOVE THROUGH TONIGHT...WITH WINDS TURNING WESTERLY AND EVENTUALLY
NORTHWESTERLY. WINDS WILL BEGIN TO PICK UP BY MORNING...WITH GUSTS
UP TO 35 KTS BY MID MORNING. STRATUS WILL LIKELY MAKE A RETURN IN
THE MORNING AS WELL...WITH MVFR CIGS EXPECTED ACROSS MOST OF THE
CWA. /CHENARD
&&
.PREVIOUS DISCUSSION.../ISSUED AT 243 AM CST/
ONE FINAL MILD DAY TODAY BEFORE A WEEK OF BELOW NORMAL TEMPERATURES
COMING UP. YESTERDAY GOT A LITTLE WARMER THAN ANTICIPATED AND SEE NO
REASON WHY TEMPERATURES WILL NOT WARM NICELY TODAY. COMPARING
YESTERDAYS 925MB TEMPERATURES WITH WHAT IS EXPECTED TODAY PLAN ON
MOST LOCATIONS ADDING ABOUT 5 TO 10 DEGREES TO HIGHS TODAY WITH LESS
CLOUD COVER AND A WARMER LOW LEVEL THERMAL FIELD. SO...HIGHS SHOULD
RANGE FROM THE MID 30S ALONG HIGHWAY 14 TO AROUND 50 DOWN THE
MISSOURI RIVER CORRIDOR. A BREEZY SOUTH WIND WILL ACCOMPANY THE WARM
UP SO THE WARMER READINGS WILL COME WITH A BIT OF A CHILL.
WINDS WILL GRADUALLY TURN TO THE NORTHWEST OVERNIGHT WITH MID AND
HIGH CLOUDS EXPECTED TO INCREASE AS WELL. THIS WILL KEEP
TEMPERATURES FROM FALLING SO ANTICIPATE A MILD MONDAY
MORNING...ALBEIT BRIEFLY AS THE FRONT SURGES SOUTH FAIRLY QUICKLY
MONDAY MORNING. LOW TEMPERATURES WILL MAINLY BE IN THE 20S WITH HIGH
TEMPERATURES ON MONDAY REACHED FAIRLY EARLY IN THE MORNING THEN
FALLING THROUGH THE DAY. STILL LOOKS LIKE NEAR WIND ADVISORY
CRITERIA BUT WILL HOLD OFF ON ANY ADVISORIES AT THIS TIME. WITH
925MB WINDS AROUND 30 TO 35 KNOTS THE SURFACE WIND USUALLY DOES NOT
QUITE REACH WIND ADVISORY CRITERIA BUT IF MODELS TREND CLOSER TO 40
KNOTS AN ADVISORY MAY BE NEEDED AS MIXING WILL BE SIGNIFICANT WITH
STRONG COLD AIR ADVECTION THROUGH THE DAY.
MUCH COLDER AIR WILL WORK INTO THE AREA MONDAY NIGHT INTO TUESDAY
LEADING TOWARDS ONE OF THE COLDER PERIODS THIS WINTER. TUESDAY
MORNING LOWS WILL DROP TO AROUND ZERO TO BELOW ZERO FROM INTERSTATE
90 NORTH AND WHEN COUPLED WITH A FAIRLY STOUT NORTH WIND...WIND
CHILL VALUES WILL DROP TO 20 TO 30 BELOW ZERO FOR A TIME FROM ABOUT
MIDNIGHT TO NOON TUESDAY. A WIND CHILL ADVISORY MAY BE NEEDED FOR
THIS TIME FRAME. ALSO OF CONCERN LATE MONDAY AFTERNOON AND MONDAY
NIGHT WILL BE A WEAK WAVE MOVING EAST THROUGH THE REGION WHICH COULD
BRING SOME LIGHT SNOW AND BLOWING SNOW DOWN THE HIGHWAY 14 CORRIDOR.
WILL MAINTAIN SOME LOWER END POPS TO ACCOMMODATE THIS THREAT.
IN THE LATTER PERIODS(WED/SAT)...THIS PERIOD CONTINUES TO BE
DOMINATED BY THE POTENTIAL FOR A WINTER STORM ON THURSDAY AND
THURSDAY NIGHT. ALL INDICATIONS ARE THAT THIS WILL LEAN MORE TOWARDS
AN ISENTROPIC WIDESPREAD MODERATE TO HEAVY SNOW EVENT VS. A FRONTAL
BAND OR A RAPIDLY DEEPENING HIGH WIND/BLIZZARD LIKE EVENT. SO MAYBE
LOOKING AT 5 TO 10 INCHES OF SNOWFALL WITH WINDS IN THE 15 TO 30 MPH
RANGE AND NOT BECOMING EXCESSIVELY COLD BEHIND THE SYSTEM. WITH THIS
IN MIND ANTICIPATE THAT ANY STORM TRACK THAT KEEPS THE UPPER LEVEL
LOW ALONG AND SOUTH OF THE CWA WILL BRING A DECENT AMOUNT OF SNOW TO
MOST OF THE AREA. THE LATEST ECMWF IS TAKING A BIT OF A TURN TO THE
NORTHWEST WHICH IF THIS TREND CONTINUED COULD TAKE A LOT OF THE
HEAVIEST ACTIVITY TO THE NORTH AND WEST OF THE AREA. HOWEVER...FEEL
THAT THERE WILL BE PLENTY OF MOISTURE WITH THIS SYSTEM THAT IT WILL
TAKE SOME PRETTY BIG CHANGES TO THE NORTH AND WEST TO NOT GET SOME
MEASURABLE SNOWFALL. THUS WILL CONTINUE WITH 80+ POPS FOR THURSDAY
AND THURSDAY NIGHT MANY AREAS AND CONTINUE TO HINT AT THE POTENTIAL
FOR A WINTER STORM/HEAVY SNOW IN THE HWO. GENERALLY THINKING HIGHS
IN THE UPPER TEENS TO 20S AS THE STORM EXITS ON FRIDAY AND SATURDAY.
/08
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1016 AM CST SUN FEB 17 2013
.DISCUSSION.../ISSUED AT 1015 AM CST/
SURFACE LOW PRESSURE MOVING ACROSS THE CANADIAN BORDER WILL PUSH A
COLD FRONT THROUGH THE AREA TONIGHT. TODAY WILL BE A MILD AND BREEZY
DAY OUT AHEAD OF THIS FRONT. STILL EXPECTING SOUTHERLY WINDS TO
CONTINUE TO INCREASE THIS AFTERNOON...WITH GUSTS AROUND 30
MPH...ESPECIALLY ALONG AND EAST OF INTERSTATE 29. SEEING A BIT MORE
CIRRUS THAN FORECAST..SO WENT AHEAD AND UPPED CLOUD COVER...HOWEVER
SHOULD STILL SEE PARTLY SUNNY SKIES. CIRRUS PROBABLY WONT HAVE TOO
MUCH OF AN IMPACT ON HIGHS...ESPECIALLY SINCE A THINNER AREA SHOULD
BE OVER THE CWA FOR THE NEXT SEVERAL HOURS. GOING HIGHS LOOK IN
PRETTY GOOD SHAPE...ALTHOUGH DID GO AHEAD AND RAISE HIGHS A COUPLE
DEGREES IN OUR SOUTH BASED ON LATEST RAP AND HRRR TRENDS. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 243 AM CST/
ONE FINAL MILD DAY TODAY BEFORE A WEEK OF BELOW NORMAL TEMPERATURES
COMING UP. YESTERDAY GOT A LITTLE WARMER THAN ANTICIPATED AND SEE NO
REASON WHY TEMPERATURES WILL NOT WARM NICELY TODAY. COMPARING
YESTERDAYS 925MB TEMPERATURES WITH WHAT IS EXPECTED TODAY PLAN ON
MOST LOCATIONS ADDING ABOUT 5 TO 10 DEGREES TO HIGHS TODAY WITH LESS
CLOUD COVER AND A WARMER LOW LEVEL THERMAL FIELD. SO...HIGHS SHOULD
RANGE FROM THE MID 30S ALONG HIGHWAY 14 TO AROUND 50 DOWN THE
MISSOURI RIVER CORRIDOR. A BREEZY SOUTH WIND WILL ACCOMPANY THE WARM
UP SO THE WARMER READINGS WILL COME WITH A BIT OF A CHILL.
WINDS WILL GRADUALLY TURN TO THE NORTHWEST OVERNIGHT WITH MID AND
HIGH CLOUDS EXPECTED TO INCREASE AS WELL. THIS WILL KEEP
TEMPERATURES FROM FALLING SO ANTICIPATE A MILD MONDAY
MORNING...ALBEIT BRIEFLY AS THE FRONT SURGES SOUTH FAIRLY QUICKLY
MONDAY MORNING. LOW TEMPERATURES WILL MAINLY BE IN THE 20S WITH HIGH
TEMPERATURES ON MONDAY REACHED FAIRLY EARLY IN THE MORNING THEN
FALLING THROUGH THE DAY. STILL LOOKS LIKE NEAR WIND ADVISORY
CRITERIA BUT WILL HOLD OFF ON ANY ADVISORIES AT THIS TIME. WITH
925MB WINDS AROUND 30 TO 35 KNOTS THE SURFACE WIND USUALLY DOES NOT
QUITE REACH WIND ADVISORY CRITERIA BUT IF MODELS TREND CLOSER TO 40
KNOTS AN ADVISORY MAY BE NEEDED AS MIXING WILL BE SIGNIFICANT WITH
STRONG COLD AIR ADVECTION THROUGH THE DAY.
MUCH COLDER AIR WILL WORK INTO THE AREA MONDAY NIGHT INTO TUESDAY
LEADING TOWARDS ONE OF THE COLDER PERIODS THIS WINTER. TUESDAY
MORNING LOWS WILL DROP TO AROUND ZERO TO BELOW ZERO FROM INTERSTATE
90 NORTH AND WHEN COUPLED WITH A FAIRLY STOUT NORTH WIND...WIND
CHILL VALUES WILL DROP TO 20 TO 30 BELOW ZERO FOR A TIME FROM ABOUT
MIDNIGHT TO NOON TUESDAY. A WIND CHILL ADVISORY MAY BE NEEDED FOR
THIS TIME FRAME. ALSO OF CONCERN LATE MONDAY AFTERNOON AND MONDAY
NIGHT WILL BE A WEAK WAVE MOVING EAST THROUGH THE REGION WHICH COULD
BRING SOME LIGHT SNOW AND BLOWING SNOW DOWN THE HIGHWAY 14 CORRIDOR.
WILL MAINTAIN SOME LOWER END POPS TO ACCOMMODATE THIS THREAT.
IN THE LATTER PERIODS(WED/SAT)...THIS PERIOD CONTINUES TO BE
DOMINATED BY THE POTENTIAL FOR A WINTER STORM ON THURSDAY AND
THURSDAY NIGHT. ALL INDICATIONS ARE THAT THIS WILL LEAN MORE TOWARDS
AN ISENTROPIC WIDESPREAD MODERATE TO HEAVY SNOW EVENT VS. A FRONTAL
BAND OR A RAPIDLY DEEPENING HIGH WIND/BLIZZARD LIKE EVENT. SO MAYBE
LOOKING AT 5 TO 10 INCHES OF SNOWFALL WITH WINDS IN THE 15 TO 30 MPH
RANGE AND NOT BECOMING EXCESSIVELY COLD BEHIND THE SYSTEM. WITH THIS
IN MIND ANTICIPATE THAT ANY STORM TRACK THAT KEEPS THE UPPER LEVEL
LOW ALONG AND SOUTH OF THE CWA WILL BRING A DECENT AMOUNT OF SNOW TO
MOST OF THE AREA. THE LATEST ECMWF IS TAKING A BIT OF A TURN TO THE
NORTHWEST WHICH IF THIS TREND CONTINUED COULD TAKE A LOT OF THE
HEAVIEST ACTIVITY TO THE NORTH AND WEST OF THE AREA. HOWEVER...FEEL
THAT THERE WILL BE PLENTY OF MOISTURE WITH THIS SYSTEM THAT IT WILL
TAKE SOME PRETTY BIG CHANGES TO THE NORTH AND WEST TO NOT GET SOME
MEASURABLE SNOWFALL. THUS WILL CONTINUE WITH 80+ POPS FOR THURSDAY
AND THURSDAY NIGHT MANY AREAS AND CONTINUE TO HINT AT THE POTENTIAL
FOR A WINTER STORM/HEAVY SNOW IN THE HWO. GENERALLY THINKING HIGHS
IN THE UPPER TEENS TO 20S AS THE STORM EXITS ON FRIDAY AND SATURDAY.
/08
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
VERY LOCAL CEILINGS BELOW 1K FEET THROUGH 16Z WITH PATCHES AT 12Z
JUST WEST OF HON AND NORTHEAST OF FSD. OTHERWISE VFR CONDITIONS
EXPECTED THROUGH 18/12Z. CEILINGS WILL BE UNLIMITED MOST OF THIS
TIME BUT MAY LOWER TO 3-5K FEET NORTH AFTER 18/06Z. FURTHER LOWERING
TO MVFR CEILINGS POSSIBLE OVER AREA AFTER 18/12Z. SOUTH WINDS
THROUGH 18/03Z SHOULD GRADUALLY BECOME WEST AND NORTHWEST AFTER
18/03Z BUT GUSTS ARE EXPECTED TO STAY BELOWE 25 KNOTS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$