Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/14/13
AREA FORECAST DISCUSSION
NWS TAUNTON MA
717 AM EDT TUE MAR 12 2013
.SYNOPSIS...
A COLD FRONT WILL BRING WET WEATHER TO THE REGION...WITH LOCALLY
HEAVY RAINFALL...TODAY INTO TONIGHT. MAINLY DRY AND CHILLIER
WEATHER WILL RETURN WED NIGHT INTO FRI BEHIND THIS COLD FRONT. A
LOW PRESSURE MAY BRING SOME RAIN OR SNOW TO THE REGION SAT. DRY
AND UNSEASONABLY CHILLY WEATHER IS EXPECTED SUNDAY INTO MON...BUT
THERE IS THE POTENTIAL FOR A SIGNIFICANT STORM IN THE EARLY TO
MIDDLE PORTION OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
RAIN WITH EMBEDDED HEAVIER SHOWERS BEGINNING TO PRESS INTO THE
WESTERN FORECAST AREA. SOUTHERLY FLOW IS BEGINNING TO ENHANCE WITH
THE APPROACH OF THE COLD FRONT DRIVING BOTH TEMPERATURES AND
DEWPOINTS GRADUALLY HIGHER. HAVE SEEN A NON-DIURNAL TREND IN
TEMPERATURES OVERNIGHT...AND ANTICIPATE WARMING THROUGHOUT THE DAY
PRIOR TO THE COLD FRONTAL PASSAGE LATE.
FORECAST TRENDS ARE ON TRACK AND THERE HAS BEEN LITTLE CHANGE IN
THE FORECAST THE PAST 3 HOURS OTHER THAN MODIFYING THE ANTICIPATED
FOG OUTCOMES. STILL A CONSIDERABLE CHALLENGE...BUT EXPECT MUCH OF
THE REGION TO BE IN A SOUP AS A VERY MOIST AIRMASS ADVECTS NORTH
ACROSS A GROUND IN WHERE SOIL TEMPERATURES ARE AT /ESPECIALLY FOR
SNOW COVERED AREAS/ OR JUST ABOVE FREEZING.
PREVIOUS DISCUSSION...
12/00Z GUIDANCE SUITE IS IN FAIRLY GOOD AGREEMENT WITH THE TIMING
OF A COLD FRONT ACROSS SOUTHERN NEW ENGLAND LATER TODAY. GENERALLY
USED A BLEND OF THE 12/03Z RAP AND 11/21Z SREF SINCE THEY SEEMED
TO HAVE A GOOD HANDLE ON THE TIMING DETAILS OF THIS FRONT.
TEMPERATURES WILL LIKELY REMAIN WELL ABOVE FREEZING THE REST OF
THE EARLY MORNING HOURS...WHICH MEANS CONTINUING SNOW MELT ACROSS
THE REGION. THIS SNOW MELT COMBINED WITH EXPECTED RAINFALL LATER
TODAY...COULD LEAD TO MINOR FLOODING. MORE DETAILS IN THE
HYDROLOGY SECTION BELOW.
A BLEND OF MOS GUIDANCE LOOKS QUITE REASONABLE FOR TEMPERATURES
TODAY. NOT MUCH SUNSHINE EXPECTED...BUT AN INCREASING SOUTH WIND
SHOULD BE THE DRIVING FORCE FOR WARMER TEMPERATURES TODAY.
CONVECTIVE INDICES INDICATE SOME POTENTIAL FOR THUNDERSTORMS THIS
AFTERNOON. AT THIS TIME THINKING THUNDER IS TOO LOW A PROBABILITY
TO WARRANT A MENTION IN THE FORECAST. DO THINK THERE WILL BE AREAS
OF MODERATE TO HEAVY RAINFALL THOUGH. STILL THINKING ABOUT
POSSIBLY EXPANDING FLOOD WATCH TO COVER OTHER PORTIONS OF SOUTHERN
NEW ENGLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
EXPECTING THIS COLD FRONT TO PUSH OFFSHORE AFTER MIDNIGHT. STILL A
LOW PROBABILITY FOR THUNDERSTORMS UNTIL IT DOES. EXPECTING DRY
WEATHER ACROSS ALL OF SOUTHERN NEW ENGLAND BY MID-MORNING
WEDNESDAY. DRIER WEATHER WITH MORE SUNSHINE EXPECTED ACROSS ALL OF
SOUTHERN NEW ENGLAND FOR WEDNESDAY AFTERNOON.
TEMPERATURES FOR MOST AREAS WILL LIKELY REMAIN ABOVE FREEZING
TONIGHT AS WELL...CONTINUING THE SNOW MELT PROCESS. EXPECTING
TEMPERATURES TO BE 10-15 DEGREES ABOVE NORMAL TONIGHT AND
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HEADLINES...
* BELOW-NORMAL CONDITIONS FOR WEDNESDAY NIGHT INTO FRIDAY NIGHT.
* CLIPPER LOW AND SOME POSSIBLE SNOW ACCUMULATIONS FOR SATURDAY.
* A RETURN OF BELOW-NORMAL CONDITIONS SUNDAY INTO MONDAY.
* POTENTIAL STORM BY TUESDAY INTO THE LATE WEEK.
*/OVERVIEW AND MODEL CONSENSUS...
A STRONG NEGATIVE NAO/AO STATE IS IN THE CARDS AS ANOMALOUS RIDGING
/HEIGHT RISES/ ACROSS THE DAVIS STRAIGHT AND GREENLAND PERSERVERE
THROUGH THE MAJORITY OF THE LONG-TERM FORECAST. THE STRONG
BLOCKING PATTERN LENDS TO PRONOUNCED AND PROLONGED TROUGHING
ACROSS THE NORTHEASTERN CONUS AND EASTERN CANADIAN MARITIMES.
CONSEQUENTIAL TO THE TROUGHING PATTERN...COOLER CONDITIONS ARE
ANTICIPATED WITH H85 TEMPERATURES REMAINING A FEW TO SEVERAL
DEGREES BELOW FREEZING AND COLDER ARCTIC AIR BUILDING SOUTH INTO
CENTRAL CANADA. AN ACTIVE PATTERN IS IN STORE AND IT DOES NOT
APPEAR WE ARE OUT OF THE WOODS YET IN REGARDS TO WINTER STORMS. IT
SHOULD NOT COME AS A SURPRISE THAT THE BULK OF THE FORECAST HINGES
UPON OUTCOMES FORECAST BY THE ECMWF...WITH SOME WEIGHT OF THE
GFS/NAM/CANADIAN OUT TO MONDAY.
*/DAY-TO-DAY DETAILS...
*/WEDNESDAY NIGHT INTO FRIDAY NIGHT...
COLDER AIRMASS BUILDING ACROSS THE REGION UNDER NORTHWESTERLY FLOW
WILL MAKE FOR BELOW NORMAL TEMPERATURES FOR THE FORECAST PERIOD.
INITIALLY COOL WEDNESDAY INTO THURSDAY...WILL SEE A REINFORCING SHOT
OF ARCTIC-LIKE AIR THURSDAY NIGHT INTO FRIDAY BEHIND A DRY SECONDARY
COLD FRONT. MAY SEE A SPOT SHOWER ALONG THE FRONT...BUT AIRMASS IS
CONTINENTAL-POLAR IN NATURE WITH LITTLE AVAILABLE MOISTURE. BEST
CHANCE FOR ANY SNOW SHOWERS WILL BE ALONG NORTH/WEST FACING HIGHER
TERRAIN /DOWNWARD SLOPING COMPONENT OF WIND ON THE LEEWARD SIDES OF
HIGHER TERRAIN SHOULD DIMINISH POP CHANCES OTHERWISE...AND LIKELY
WILL MAKE CLOUD COVER A NON-ISSUE/. STEEP LOW-LEVEL LAPSE RATES UP
TO AROUND H85 ALLOWING FOR MIX-DOWN OF FASTER MOMENTUM ALOFT AND
DRIER AIR DURING THE DAY /MORE BLUSTERY FRIDAY/.
*/SATURDAY INTO SATURDAY NIGHT...
WEAK WAVE QUICK-MOVING CLIPPER LOW SWEEPS ACROSS NEW ENGLAND WITH
THE POSSIBILITY OF LIGHT SNOW ACCUMULATIONS /BELOW ADVISORY LEVEL/.
WITH SOME UNCERTAINTY...WILL LEAN WITH A SOUTHERN LOW SOLUTION. A
FEW POINTS TO CONSIDER...AS THE WAVE APPROACHES AND THEN EMERGES
OFFSHORE...MID-LEVEL FLOW IS AMPLIFIED IN RESPONSE TO THE WAVE
MOVING INTO A REGION OF BETTER BAROCLINICITY...SUBSEQUENTLY
DEEPENING. AN AREA OF LOCALIZED CONVERGENCE IS PRESENT ACROSS
INTERIOR NEW ENGLAND AND EFFECTIVE MOISTURE TRANSPORT EMERGES WITHIN
THE LOW-LEVELS TO TAP INTO THE WESTERN ATLANTIC. WHILE BELIEVED THAT
PRIOR BELOW-NORMAL CONDITIONS WILL NOT BE WASHED OUT EFFECTIVELY
ACROSS THE INTERIOR...THE DAYTIME PASSAGE WILL LIKELY RESULT IN SOME
CAVEATS WITH REGARDS TO SNOW ACCUMULATIONS. BEST SNOW ACCUMULATIONS
SHOULD BE ACROSS INTERIOR NEW ENGLAND...ESPECIALLY ACROSS HIGHER
TERRAIN. LIKELY POPS ARE WARRANTED AS A MAJORITY OF MODEL SOLUTIONS
ARE IN AGREEMENT.
*/SUNDAY INTO MONDAY...
COLDER AIR RESURGES BACK ACROSS THE REGION SUNDAY AND SUNDAY
NIGHT UNDER NORTH-NORTHWEST FLOW /BLUSTERY AT TIMES AS WELL-MIXED
LAPSE RATES UP TO H85 WILL ALLOW FOR THE MIX-DOWN OF FASTER
MOMENTUM AND DRIER AIR/. TEMPERATURES MAY BE ABLE TO DROP
SIGNIFICANTLY SUNDAY NIGHT SHOULD HIGH PRESSURE DOMINATE THE AREAS
WEATHER LENDING TO LIGHT AND VARIABLE WINDS /EFFECTIVE RADIATIONAL
COOLING/. MONDAY APPEARS TO BE ON THE MORE MILD SIDE AS HIGH
PRESSURE SHIFTS EAST ALLOWING FOR MORE EAST-SOUTHEASTERLY ONSHORE
FLOW. PER THE ECMWF...SHOULD BEGIN TO SEE THE INCREASE IN CLOUDS
AND PRECIPITATION ALONG AND AHEAD AN ATTENDANT APPROACHING WARM
FRONT.
*/MONDAY NIGHT INTO WEDNESDAY...
ECMWF HAS BEEN CONSISTENT ON A POTENTIAL STORM BUT HAS DIFFERED ON
OUTCOMES. UNCERTAIN WITH SPECIFICS. SHOULD THE STORM BE AN INSIDE
RUNNER AND A DOUBLE BARREL LOW SETUP...ARCTIC AIR WILL BE DIS-
CONNECTED FROM THE EASTERLY LOW. SUCH A SETUP WOULD YIELD INTERIOR
HIGHER ELEVATION SNOWS...OTHERWISE WITH THE COUPLED FACT OF A
DAYTIME WARM FRONTAL PASSAGE ON TUESDAY...THIS STORM MAY BE NOTHING
MORE THAN A WET-SNOW NUISANCE TRANSITIONING TO RAIN /STILL SOME
QUESTION ON POTENTIAL COLD AIR DAMMING/. DO NOT TRUST THE FORECASTED
SNOW OUTCOMES PER THE ECMWF.
DRY SLOTTING COULD TAKE PLACE WEDNESDAY AS THE LOW UNDERGOES
OCCLUSION BECOMING STACKED. PRECIPITATION CHANCES MAY INCREASE
BEYOND WEDNESDAY INTO THE LATE WEEK AS THE STACKED LOW WOBBLES
ACROSS NEW ENGLAND...UNABLE TO EXIT STAGE LEFT AGAINST THE
AFOREMENTIONED ANOMALOUS RIDGING OVER THE DAVIS
STRAIGHT/GREENLAND.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR-TERM /INTO WEDNESDAY/...HIGH CONFIDENCE.
ALONG AND AHEAD OF AN APPROACHING COLD FRONT...RAIN WILL
OVERSPREAD THE TERMINALS WITH EMBEDDED HEAVIER SHOWERS. ANTICIPATING
A MIX OF MVFR-LIFR CIGS AND MVFR-IFR VSBYS. CONDITIONS ARE LIKELY
TO WOBBLE THROUGHOUT THE DAY. WITH HEAVIER SHOWERS...LIFR VSBYS
BELOW 1 SM ARE POSSIBLE. LLWS WILL ALSO BE AN ISSUE WITH STRONG
SOUTHERLY FLOW AROUND 50 KTS AT 2 KFT AGL PRIOR TO THE COLD FRONT.
CONDITIONS WILL QUICKLY IMPROVE TO VFR AFTER THE PASSAGE OF THE
COLD FRONT. HAVE GONE WITH GRADUAL IMPROVING TRENDS AS THERE STILL
REMAINS SOME UNCERTAINTY. WINDS TO BACK OUT OF THE W/NW.
KBOS TAF...MODERATE CONFIDENCE IN TAF.
KBDL TAF...MODERATE CONFIDENCE IN TAF.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE TO HIGH CONFIDENCE.
NW WINDS...BLUSTERY MORE SO THURSDAY NIGHT INTO FRIDAY. BETTER
CHANCES OF LOW-VFR CLOUDS OVER WESTERN AND CENTRAL HIGH TERRAIN.
SATURDAY...MODERATE CONFIDENCE.
LIGHT SN OVERSPREADING TERMINALS...TRANSITIONING TO LIGHT RA S/SE
TO N/NW. LOW VFR TO MVFR CIGS WITH MVFR-IFR VSBYS. SOUTHERLY FLOW
INITIALLY BECOMING LIGHT AND VARIABLE BEFORE BACKING OUT OF THE NW
LATE.
&&
.MARINE...
TONIGHT THROUGH TUESDAY NIGHT...HIGH CONFIDENCE.
HIGH SWELLS CONTINUE ACROSS THE OPEN WATERS...BUT ALSO EXPECT S-SW
WINDS TO PICK UP TODAY. SMALL CRAFT ADVISORIES EXTENDED INTO
WEDNESDAY FOR MOST WATERS AS SEAS WILL REMAIN ROUGH...ESPECIALLY
ACROSS THE COASTAL WATERS LOW PROBABILITY FOR 25 KT WIND GUSTS
ACROSS CAPE COD BAY AND NANTUCKET SOUND. SMALL CRAFT ADVISORIES
MAY NEED TO BE EXPANDED THERE BY NEXT SHIFT.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE TO HIGH CONFIDENCE.
NORTHWEST WINDS...THE STRONGER AND MORE BLUSTERY OF WHICH WILL BE
THURSDAY NIGHT INTO FRIDAY WITH GUSTS EXCEEDING 25 KTS. ANTICIPATE
SEAS IN EXCESS OF 5 FEET ON THE OUTER WATERS...POSSIBLY INTO RI/BI
SOUNDS.
SATURDAY...MODERATE CONFIDENCE.
WINDS VEERING OUT OF THE SOUTH INITIALLY...BECOMING LIGHT AND
VARIABLE INTO EVENING AS AN AREA OF LOW PRESSURE SWEEPS ACROSS THE
WATERS...THEN BACKING OUT OF THE NORTHWEST LATE INTO SUNDAY MORNING.
SEAS WILL BE ALLOWED TO SUBSIDE FOR A MAJORITY OF THE PERIOD BEFORE
BECOMING CHOPPY AGAIN LATE SATURDAY INTO SATURDAY NIGHT.
&&
.HYDROLOGY...
RAINFALL AND SNOW MELT THIS AFTERNOON AND EVENING MAY BE ENOUGH
TO PRODUCE MINOR FLOODING OF SOME SMALL STREAMS AS WELL AS POOR
DRAINAGE FLOODING ACROSS PORTIONS OF MA AND NH WHERE A FLOOD
WATCH HAS BEEN ISSUED. RAINFALL PROJECTED TO APPROACH AN INCH IN
6 TO 8 HOURS. MODELS INDICATE A 40 TO 50 KT LOW LEVEL JET BUT LOW
LEVEL THERMO PROFILE INDICATES THAT ONLY A LITTLE BIT OF THAT WIND
IS LIKELY TO MIX DOWN TO THE SURFACE. THE SNOW PACK ACROSS MOST OF
SOUTHERN NEW ENGLAND IS FAIRLY RIPE WITH TEMPERATURES NEAR
32F. THE EXPECTED RAINFALL WITH DEWPOINTS IN THE MID/UPPER 40S
OUGHT TO RELEASE AT LEAST AN INCH OR SO OF WATER FROM THE
SNOWPACK.
AS FAR AS THE MAINSTEM RIVERS...NERFC GUIDANCE SHOWS ONLY THE
ASSABET AT MAYNARD GOING INTO FLOOD WITH GENERALLY 2+ INCHES OF
RAIN NEEDED TO BRING OTHER FORECAST POINTS INTO FLOOD. EVEN
SO...WE SHOULD KEEP AN EYE ON THE NORTH NASHUA AT FITCHBURG AND
THE SHAWSHEEN. BOTH THE SUDBURY AND PAWTUXET MAY SHOW FAIRLY SHARP
RISES BUT FOR NOW ARE EXPECTED TO REMAIN BELOW FLOOD STAGE UNLESS
SIGNIFICANTLY HEAVIER RAIN AND/OR HIGHER DEWPOINTS OCCUR. SLOW
RISERS SUCH AS THE CHARLES AT DOVER...TAUNTON AT W BRIDGEWATER
WILL LIKELY REMAIN BELOW FLOOD STAGE BUT BECOME ELEVATED AND
SUSCEPTIBLE TO ANY HEAVY RAIN EVENTS IN THE NOT TOO DISTANT
FUTURE. WILL ALSO HAVE TO WATCH THE CONNECTICUT RIVER ONCE LATER
THIS WEEK AS WATER ENTERING THE RIVER FROM NORTHERN NEW ENGLAND
MAKES ITS WAY SOUTH.
THE RAIN THIS AFTERNOON AND EVENING SHOULD BE HEAVY ENOUGH TO
CAUSE LOCALIZED STREET/POOR DRAINAGE FLOODING...ESPECIALLY WHERE
SNOW MIGHT BE BLOCKING CATCH BASINS OR DRAINS. THIS COULD HAVE
SOME IMPACT ON THE EVENING COMMUTE.
EXPANDED THE FLOOD WATCH ACROSS SOUTHERN NH AND WESTERN MA DUE TO
POTENTIAL FOR LOCALLY HEAVIER RAINFALL AS WELL AS STRONG SNOW MELT
ACROSS THE HIGHER ELEVATIONS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR MAZ002>006-008>014-017-018-026.
NH...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR NHZ011-012-015.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR ANZ233-234.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ235-237-
250-251-254>256.
&&
$$
SYNOPSIS...BELK/SIPPRELL
NEAR TERM...BELK/SIPPRELL
SHORT TERM...BELK
LONG TERM...SIPPRELL
AVIATION...BELK/SIPPRELL
MARINE...BELK/SIPPRELL
HYDROLOGY...BELK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
435 AM EDT TUE MAR 12 2013
.SYNOPSIS...
A COLD FRONT WILL BRING WET WEATHER TO THE REGION...WITH LOCALLY
HEAVY RAINFALL...TODAY INTO TONIGHT. MAINLY DRY AND CHILLIER
WEATHER WILL RETURN WED NIGHT INTO FRI BEHIND THIS COLD FRONT. A
LOW PRESSURE MAY BRING SOME RAIN OR SNOW TO THE REGION SAT. DRY
AND UNSEASONABLY CHILLY WEATHER IS EXPECTED SUNDAY INTO MON...BUT
THERE IS THE POTENTIAL FOR A SIGNIFICANT STORM IN THE EARLY TO
MIDDLE PORTION OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
12/00Z GUIDANCE SUITE IS IN FAIRLY GOOD AGREEMENT WITH THE TIMING
OF A COLD FRONT ACROSS SOUTHERN NEW ENGLAND LATER TODAY. GENERALLY
USED A BLEND OF THE 12/03Z RAP AND 11/21Z SREF SINCE THEY SEEMED
TO HAVE A GOOD HANDLE ON THE TIMING DETAILS OF THIS FRONT.
TEMPERATURES WILL LIKELY REMAIN WELL ABOVE FREEZING THE REST OF
THE EARLY MORNING HOURS...WHICH MEANS CONTINUING SNOW MELT ACROSS
THE REGION. THIS SNOW MELT COMBINED WITH EXPECTED RAINFALL LATER
TODAY...COULD LEAD TO MINOR FLOODING. MORE DETAILS IN THE
HYDROLOGY SECTION BELOW.
A BLEND OF MOS GUIDANCE LOOKS QUITE REASONABLE FOR TEMPERATURES
TODAY. NOT MUCH SUNSHINE EXPECTED...BUT AN INCREASING SOUTH WIND
SHOULD BE THE DRIVING FORCE FOR WARMER TEMPERATURES TODAY.
CONVECTIVE INDICES INDICATE SOME POTENTIAL FOR THUNDERSTORMS THIS
AFTERNOON. AT THIS TIME THINKING THUNDER IS TOO LOW A PROBABILITY
TO WARRANT A MENTION IN THE FORECAST. DO THINK THERE WILL BE AREAS
OF MODERATE TO HEAVY RAINFALL THOUGH. STILL THINKING ABOUT
POSSIBLY EXPANDING FLOOD WATCH TO COVER OTHER PORTIONS OF SOUTHERN
NEW ENGLAND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
EXPECTING THIS COLD FRONT TO PUSH OFFSHORE AFTER MIDNIGHT. STILL A
LOW PROBABILITY FOR THUNDERSTORMS UNTIL IT DOES. EXPECTING DRY
WEATHER ACROSS ALL OF SOUTHERN NEW ENGLAND BY MID-MORNING
WEDNESDAY. DRIER WEATHER WITH MORE SUNSHINE EXPECTED ACROSS ALL OF
SOUTHERN NEW ENGLAND FOR WEDNESDAY AFTERNOON.
TEMPERATURES FOR MOST AREAS WILL LIKELY REMAIN ABOVE FREEZING
TONIGHT AS WELL...CONTINUING THE SNOW MELT PROCESS. EXPECTING
TEMPERATURES TO BE 10-15 DEGREES ABOVE NORMAL TONIGHT AND
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HEADLINES...
* BELOW-NORMAL CONDITIONS FOR WEDNESDAY NIGHT INTO FRIDAY NIGHT.
* CLIPPER LOW AND SOME POSSIBLE SNOW ACCUMULATIONS FOR SATURDAY.
* A RETURN OF BELOW-NORMAL CONDITIONS SUNDAY INTO MONDAY.
* POTENTIAL STORM BY TUESDAY INTO THE LATE WEEK.
*/OVERVIEW AND MODEL CONSENSUS...
A STRONG NEGATIVE NAO/AO STATE IS IN THE CARDS AS ANOMALOUS RIDGING
/HEIGHT RISES/ ACROSS THE DAVIS STRAIGHT AND GREENLAND PERSERVERE
THROUGH THE MAJORITY OF THE LONG-TERM FORECAST. THE STRONG
BLOCKING PATTERN LENDS TO PRONOUNCED AND PROLONGED TROUGHING
ACROSS THE NORTHEASTERN CONUS AND EASTERN CANADIAN MARITIMES.
CONSEQUENTIAL TO THE TROUGHING PATTERN...COOLER CONDITIONS ARE
ANTICIPATED WITH H85 TEMPERATURES REMAINING A FEW TO SEVERAL
DEGREES BELOW FREEZING AND COLDER ARCTIC AIR BUILDING SOUTH INTO
CENTRAL CANADA. AN ACTIVE PATTERN IS IN STORE AND IT DOES NOT
APPEAR WE ARE OUT OF THE WOODS YET IN REGARDS TO WINTER STORMS. IT
SHOULD NOT COME AS A SURPRISE THAT THE BULK OF THE FORECAST HINGES
UPON OUTCOMES FORECAST BY THE ECMWF...WITH SOME WEIGHT OF THE
GFS/NAM/CANADIAN OUT TO MONDAY.
*/DAY-TO-DAY DETAILS...
*/WEDNESDAY NIGHT INTO FRIDAY NIGHT...
COLDER AIRMASS BUILDING ACROSS THE REGION UNDER NORTHWESTERLY FLOW
WILL MAKE FOR BELOW NORMAL TEMPERATURES FOR THE FORECAST PERIOD.
INITIALLY COOL WEDNESDAY INTO THURSDAY...WILL SEE A REINFORCING SHOT
OF ARCTIC-LIKE AIR THURSDAY NIGHT INTO FRIDAY BEHIND A DRY SECONDARY
COLD FRONT. MAY SEE A SPOT SHOWER ALONG THE FRONT...BUT AIRMASS IS
CONTINENTAL-POLAR IN NATURE WITH LITTLE AVAILABLE MOISTURE. BEST
CHANCE FOR ANY SNOW SHOWERS WILL BE ALONG NORTH/WEST FACING HIGHER
TERRAIN /DOWNWARD SLOPING COMPONENT OF WIND ON THE LEEWARD SIDES OF
HIGHER TERRAIN SHOULD DIMINISH POP CHANCES OTHERWISE...AND LIKELY
WILL MAKE CLOUD COVER A NON-ISSUE/. STEEP LOW-LEVEL LAPSE RATES UP
TO AROUND H85 ALLOWING FOR MIX-DOWN OF FASTER MOMENTUM ALOFT AND
DRIER AIR DURING THE DAY /MORE BLUSTERY FRIDAY/.
*/SATURDAY INTO SATURDAY NIGHT...
WEAK WAVE QUICK-MOVING CLIPPER LOW SWEEPS ACROSS NEW ENGLAND WITH
THE POSSIBILITY OF LIGHT SNOW ACCUMULATIONS /BELOW ADVISORY LEVEL/.
WITH SOME UNCERTAINTY...WILL LEAN WITH A SOUTHERN LOW SOLUTION. A
FEW POINTS TO CONSIDER...AS THE WAVE APPROACHES AND THEN EMERGES
OFFSHORE...MID-LEVEL FLOW IS AMPLIFIED IN RESPONSE TO THE WAVE
MOVING INTO A REGION OF BETTER BAROCLINICITY...SUBSEQUENTLY
DEEPENING. AN AREA OF LOCALIZED CONVERGENCE IS PRESENT ACROSS
INTERIOR NEW ENGLAND AND EFFECTIVE MOISTURE TRANSPORT EMERGES WITHIN
THE LOW-LEVELS TO TAP INTO THE WESTERN ATLANTIC. WHILE BELIEVED THAT
PRIOR BELOW-NORMAL CONDITIONS WILL NOT BE WASHED OUT EFFECTIVELY
ACROSS THE INTERIOR...THE DAYTIME PASSAGE WILL LIKELY RESULT IN SOME
CAVEATS WITH REGARDS TO SNOW ACCUMULATIONS. BEST SNOW ACCUMULATIONS
SHOULD BE ACROSS INTERIOR NEW ENGLAND...ESPECIALLY ACROSS HIGHER
TERRAIN. LIKELY POPS ARE WARRANTED AS A MAJORITY OF MODEL SOLUTIONS
ARE IN AGREEMENT.
*/SUNDAY INTO MONDAY...
COLDER AIR RESURGES BACK ACROSS THE REGION SUNDAY AND SUNDAY
NIGHT UNDER NORTH-NORTHWEST FLOW /BLUSTERY AT TIMES AS WELL-MIXED
LAPSE RATES UP TO H85 WILL ALLOW FOR THE MIX-DOWN OF FASTER
MOMENTUM AND DRIER AIR/. TEMPERATURES MAY BE ABLE TO DROP
SIGNIFICANTLY SUNDAY NIGHT SHOULD HIGH PRESSURE DOMINATE THE AREAS
WEATHER LENDING TO LIGHT AND VARIABLE WINDS /EFFECTIVE RADIATIONAL
COOLING/. MONDAY APPEARS TO BE ON THE MORE MILD SIDE AS HIGH
PRESSURE SHIFTS EAST ALLOWING FOR MORE EAST-SOUTHEASTERLY ONSHORE
FLOW. PER THE ECMWF...SHOULD BEGIN TO SEE THE INCREASE IN CLOUDS
AND PRECIPITATION ALONG AND AHEAD AN ATTENDANT APPROACHING WARM
FRONT.
*/MONDAY NIGHT INTO WEDNESDAY...
ECMWF HAS BEEN CONSISTENT ON A POTENTIAL STORM BUT HAS DIFFERED ON
OUTCOMES. UNCERTAIN WITH SPECIFICS. SHOULD THE STORM BE AN INSIDE
RUNNER AND A DOUBLE BARREL LOW SETUP...ARCTIC AIR WILL BE DIS-
CONNECTED FROM THE EASTERLY LOW. SUCH A SETUP WOULD YIELD INTERIOR
HIGHER ELEVATION SNOWS...OTHERWISE WITH THE COUPLED FACT OF A
DAYTIME WARM FRONTAL PASSAGE ON TUESDAY...THIS STORM MAY BE NOTHING
MORE THAN A WET-SNOW NUISANCE TRANSITIONING TO RAIN /STILL SOME
QUESTION ON POTENTIAL COLD AIR DAMMING/. DO NOT TRUST THE FORECASTED
SNOW OUTCOMES PER THE ECMWF.
DRY SLOTTING COULD TAKE PLACE WEDNESDAY AS THE LOW UNDERGOES
OCCLUSION BECOMING STACKED. PRECIPITATION CHANCES MAY INCREASE
BEYOND WEDNESDAY INTO THE LATE WEEK AS THE STACKED LOW WOBBLES
ACROSS NEW ENGLAND...UNABLE TO EXIT STAGE LEFT AGAINST THE
AFOREMENTIONED ANOMALOUS RIDGING OVER THE DAVIS
STRAIGHT/GREENLAND.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY THROUGH TONIGHT...HIGH CONFIDENCE IN TRENDS. MODERATE
CONFIDENCE IN EXACT TIMING.
EXPECT MVFR TO IFR CONDITIONS AS RAIN MOVES IN WITH DEEP LOW AND
MID LEVEL MOIST FLOW ON S-SW WINDS. MAY SEE LOCALLY HEAVY RAINFALL
NEAR AND AHEAD OF A COLD FRONT. LLWS ON 40-50 KT S-SW LOW LEVEL
JET...WHICH SHOULD SHIFT OFFSHORE AS THIS FRONT PASSES THROUGH THE
REGION THIS AFTERNOON AND OVERNIGHT. CONDITIONS IMPROVE TO VFR
SHORTLY AFTER FRONTAL PASSAGE LATE TONIGHT ACROSS CENTRAL AND
WESTERN AREAS...BUT MAY LINGER TO AROUND 12Z WED ACROSS E.
WEDNESDAY....HIGH CONFIDENCE VFR BY MID-MORNING FOR ALL OF
SOUTHERN NEW ENGLAND.
KBOS TAF...MODERATE CONFIDENCE IN TAF.
KBDL TAF...MODERATE CONFIDENCE IN TAF.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE TO HIGH CONFIDENCE.
NW WINDS...BLUSTERY MORE SO THURSDAY NIGHT INTO FRIDAY. BETTER
CHANCES OF LOW-VFR CLOUDS OVER WESTERN AND CENTRAL HIGH TERRAIN.
SATURDAY...MODERATE CONFIDENCE.
LIGHT SN OVERSPREADING TERMINALS...TRANSITIONING TO LIGHT RA S/SE
TO N/NW. LOW VFR TO MVFR CIGS WITH MVFR-IFR VSBYS. SOUTHERLY FLOW
INITIALLY BECOMING LIGHT AND VARIABLE BEFORE BACKING OUT OF THE NW
LATE.
&&
.MARINE...
TONIGHT THROUGH TUESDAY NIGHT...HIGH CONFIDENCE.
HIGH SWELLS CONTINUE ACROSS THE OPEN WATERS...BUT ALSO EXPECT S-SW
WINDS TO PICK UP TODAY. SMALL CRAFT ADVISORIES EXTENDED INTO
WEDNESDAY FOR MOST WATERS AS SEAS WILL REMAIN ROUGH...ESPECIALLY
ACROSS THE COASTAL WATERS LOW PROBABILITY FOR 25 KT WIND GUSTS
ACROSS CAPE COD BAY AND NANTUCKET SOUND. SMALL CRAFT ADVISORIES
MAY NEED TO BE EXPANDED THERE BY NEXT SHIFT.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE TO HIGH CONFIDENCE.
NORTHWEST WINDS...THE STRONGER AND MORE BLUSTERY OF WHICH WILL BE
THURSDAY NIGHT INTO FRIDAY WITH GUSTS EXCEEDING 25 KTS. ANTICIPATE
SEAS IN EXCESS OF 5 FEET ON THE OUTER WATERS...POSSIBLY INTO RI/BI
SOUNDS.
SATURDAY...MODERATE CONFIDENCE.
WINDS VEERING OUT OF THE SOUTH INITIALLY...BECOMING LIGHT AND
VARIABLE INTO EVENING AS AN AREA OF LOW PRESSURE SWEEPS ACROSS THE
WATERS...THEN BACKING OUT OF THE NORTHWEST LATE INTO SUNDAY MORNING.
SEAS WILL BE ALLOWED TO SUBSIDE FOR A MAJORITY OF THE PERIOD BEFORE
BECOMING CHOPPY AGAIN LATE SATURDAY INTO SATURDAY NIGHT.
&&
.HYDROLOGY...
RAINFALL AND SNOW MELT THIS AFTERNOON AND EVENING MAY BE ENOUGH
TO PRODUCE MINOR FLOODING OF SOME SMALL STREAMS AS WELL AS POOR
DRAINAGE FLOODING ACROSS PORTIONS OF MA AND NH WHERE A FLOOD
WATCH HAS BEEN ISSUED. RAINFALL PROJECTED TO APPROACH AN INCH IN
6 TO 8 HOURS. MODELS INDICATE A 40 TO 50 KT LOW LEVEL JET BUT LOW
LEVEL THERMO PROFILE INDICATES THAT ONLY A LITTLE BIT OF THAT WIND
IS LIKELY TO MIX DOWN TO THE SURFACE. THE SNOW PACK ACROSS MOST OF
SOUTHERN NEW ENGLAND IS FAIRLY RIPE WITH TEMPERATURES NEAR
32F. THE EXPECTED RAINFALL WITH DEWPOINTS IN THE MID/UPPER 40S
OUGHT TO RELEASE AT LEAST AN INCH OR SO OF WATER FROM THE
SNOWPACK.
AS FAR AS THE MAINSTEM RIVERS...NERFC GUIDANCE SHOWS ONLY THE
ASSABET AT MAYNARD GOING INTO FLOOD WITH GENERALLY 2+ INCHES OF
RAIN NEEDED TO BRING OTHER FORECAST POINTS INTO FLOOD. EVEN
SO...WE SHOULD KEEP AN EYE ON THE NORTH NASHUA AT FITCHBURG AND
THE SHAWSHEEN. BOTH THE SUDBURY AND PAWTUXET MAY SHOW FAIRLY SHARP
RISES BUT FOR NOW ARE EXPECTED TO REMAIN BELOW FLOOD STAGE UNLESS
SIGNIFICANTLY HEAVIER RAIN AND/OR HIGHER DEWPOINTS OCCUR. SLOW
RISERS SUCH AS THE CHARLES AT DOVER...TAUNTON AT W BRIDGEWATER
WILL LIKELY REMAIN BELOW FLOOD STAGE BUT BECOME ELEVATED AND
SUSCEPTIBLE TO ANY HEAVY RAIN EVENTS IN THE NOT TOO DISTANT
FUTURE. WILL ALSO HAVE TO WATCH THE CONNECTICUT RIVER ONCE LATER
THIS WEEK AS WATER ENTERING THE RIVER FROM NORTHERN NEW ENGLAND
MAKES ITS WAY SOUTH.
THE RAIN THIS AFTERNOON AND EVENING SHOULD BE HEAVY ENOUGH TO
CAUSE LOCALIZED STREET/POOR DRAINAGE FLOODING...ESPECIALLY WHERE
SNOW MIGHT BE BLOCKING CATCH BASINS OR DRAINS. THIS COULD HAVE
SOME IMPACT ON THE EVENING COMMUTE.
EXPANDED THE FLOOD WATCH ACROSS SOUTHERN NH AND WESTERN MA DUE TO
POTENTIAL FOR LOCALLY HEAVIER RAINFALL AS WELL AS STRONG SNOW MELT
ACROSS THE HIGHER ELEVATIONS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR MAZ002>006-008>014-017-018-026.
NH...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR NHZ011-012-015.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 AM EDT
WEDNESDAY FOR ANZ233-234.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ235-237-
250-251-254>256.
&&
$$
SYNOPSIS...BELK/SIPPRELL
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...SIPPRELL
AVIATION...BELK/SIPPRELL
MARINE...BELK/SIPPRELL
HYDROLOGY...THOMPSON/BELK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
244 AM EDT TUE MAR 12 2013
.SYNOPSIS...
A COLD FRONT WILL BRING WET WEATHER TO THE REGION...WITH LOCALLY
HEAVY RAINFALL...TODAY INTO TONIGHT. MAINLY DRY AND CHILLIER
WEATHER WILL RETURN WED NIGHT INTO FRI BEHIND THIS COLD FRONT. A
LOW PRESSURE MAY BRING SOME RAIN OR SNOW TO THE REGION SAT. DRY
AND UNSEASONABLY CHILLY WEATHER IS EXPECTED SUNDAY INTO MON...BUT
THERE IS THE POTENTIAL FOR A SIGNIFICANT STORM IN THE EARLY TO
MIDDLE PORTION OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
12/00Z GUIDANCE SUITE IS IN FAIRLY GOOD AGREEMENT WITH THE TIMING
OF A COLD FRONT ACROSS SOUTHERN NEW ENGLAND LATER TODAY. GENERALLY
USED A BLEND OF THE 12/03Z RAP AND 11/21Z SREF SINCE THEY SEEMED
TO HAVE A GOOD HANDLE ON THE TIMING DETAILS OF THIS FRONT.
TEMPERATURES WILL LIKELY REMAIN WELL ABOVE FREEZING THE REST OF
THE EARLY MORNING HOURS...WHICH MEANS CONTINUING SNOW MELT ACROSS
THE REGION. THIS SNOW MELT COMBINED WITH EXPECTED RAINFALL LATER
TODAY...COULD LEAD TO MINOR FLOODING. MORE DETAILS IN THE
HYDROLOGY SECTION BELOW.
A BLEND OF MOS GUIDANCE LOOKS QUITE REASONABLE FOR TEMPERATURES
TODAY. NOT MUCH SUNSHINE EXPECTED...BUT AN INCREASING SOUTH WIND
SHOULD BE THE DRIVING FORCE FOR WARMER TEMPERATURES TODAY.
CONVECTIVE INDICES INDICATE SOME POTENTIAL FOR THUNDERSTORMS THIS
AFTERNOON. AT THIS TIME THINKING THUNDER IS TOO LOW A PROBABILITY
TO WARRANT A MENTION IN THE FORECAST. DO THINK THERE WILL BE AREAS
OF MODERATE TO HEAVY RAINFALL THOUGH. STILL THINKING ABOUT
POSSIBLY EXPANDING FLOOD WATCH TO COVER OTHER PORTIONS OF SOUTHERN
NEW ENGLAND.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
EXPECTING THIS COLD FRONT TO PUSH OFFSHORE AFTER MIDNIGHT. STILL A
LOW PROBABILITY FOR THUNDERSTORMS UNTIL IT DOES. EXPECTING DRY
WEATHER ACROSS ALL OF SOUTHERN NEW ENGLAND BY MID-MORNING
WEDNESDAY. DRIER WEATHER WITH MORE SUNSHINE EXPECTED ACROSS ALL OF
SOUTHERN NEW ENGLAND FOR WEDNESDAY AFTERNOON.
TEMPERATURES FOR MOST AREAS WILL LIKELY REMAIN ABOVE FREEZING
TONIGHT AS WELL...CONTINUING THE SNOW MELT PROCESS. EXPECTING
TEMPERATURES TO BE 10-15 DEGREES ABOVE NORMAL TONIGHT AND
WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* MILD TEMPS WITH MAINLY DRY WEATHER WEDNESDAY
* MAINLY DRY WEATHER CONTINUES THU/FRI BUT TURNS CHILLIER
* SOME RAIN OR SNOW POSSIBLE SAT
* LARGER STORM POSSIBLE EARLY TO MIDDLE OF NEXT WEEK BUT LOW
CONFIDENCE
DETAILS...
THURSDAY AND FRIDAY...UPPER TROUGH SETTING UP OVER THE NORTHEAST
WILL RESULT IN CHILLY WEATHER WITH TEMPS A BIT BELOW NORMAL FOR
THIS TIME OF YEAR. THE TROUGH AXIS SHOULD BE TO THE EAST OF OUR
REGION...SO MAINLY DRY WEATHER IS ANTICIPATED ALTHOUGH CAN/T RULE
OUT AN INSTABILITY SPOT RAIN/SNOW SHOWER.
SATURDAY...A WAVE OF LOW PRESSURE IS EXPECTED TO CROSS SOUTHERN
NEW ENGLAND. THERE IS MODEL UNCERTAINTY IF THE WAVE OF LOW
PRESSURE WILL PASS TO OUR SOUTH OR NORTH. IF IT ENDS UP PASSING TO
OUR NORTH...MAINLY JUST SOME RAIN SHOWERS WOULD OCCUR.
HOWEVER...IF IT ENDS UP PASSING TO OUR SOUTH THERE WOULD BE A
POSSIBILITY FOR SOME ACCUMULATING SNOW FOR A PORTION OF OUR
REGION. ITS STILL 5 DAYS AWAY...SO WAY TOO EARLY TO LOCK IN ANY
SOLUTION. WE WILL SAY THAT THIS WILL BE A MUCH MORE
PROGRESSIVE/WEAKER SYSTEM WITH LESS MOISTURE THAT WHAT WAS
EXPERIENCED LAST THU NIGHT/FRI. SO WHILE ACCUMULATING SNOW IS
POSSIBLE FOR A PORTION OF OUR REGION "IF" THE WAVE PASSES TO OUR
SOUTH...THE ODDS OF A BLOCKBUSTER STORM ARE QUITE LOW. THE BEST
CHANCE OF ANY ACCUMULATING SNOW WILL BE ACROSS THE INTERIOR HIGH
TERRAIN...ESPECIALLY IF THE BULK OF THE EVENT ENDS UP OCCURRING
DURING THE DAYLIGHT HOURS.
SUNDAY AND MONDAY...DRY AND UNSEASONABLY CHILLY WEATHER FOLLOWS
THE DEPARTING LOW PRESSURE SYSTEM SUN INTO MON. THEREAFTER...THERE
ARE SOME INDICATIONS FOR THE POTENTIAL OF A SIGNIFICANT STORM FOR
THE EARLY TO MIDDLE PORTION OF NEXT WEEK. KEEP IN MIND
THOUGH...THIS IS MORE THAN A WEEK OUT SO CONFIDENCE REMAINS LOW ON
WHETHER THIS COMES TO FRUITION. IN FACT...IT WILL BE MANY DAYS
UNTIL WE WILL BE ABLE TO SAY MUCH MORE ON THIS POTENTIAL. IF IT
DOES DEVELOP THOUGH...THERE LOOKS TO BE AN UNUSUAL AMOUNT OF COLD
AIR IN PLACE FOR THE SECOND HALF OF MARCH...SO THERE WOULD BE THE
POTENTIAL FOR SOME WINTRY WEATHER AT LEAST AT THE ONSET.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY THROUGH TONIGHT...HIGH CONFIDENCE IN TRENDS. MODERATE
CONFIDENCE IN EXACT TIMING.
TODAY AND TONIGHT...EXPECT MVFR TO IFR CONDITIONS AS RAIN MOVES
IN WITH DEEP LOW AND MID LEVEL MOIST FLOW ON S-SW WINDS. MAY SEE
LOCALLY HEAVY RAINFALL NEAR AND AHEAD OF A COLD FRONT. LLWS ON
40-50 KT S-SW LOW LEVEL JET...WHICH SHOULD SHIFT OFFSHORE AS THIS
FRONT PASSES THROUGH THE REGION THIS AFTERNOON AND OVERNIGHT.
CONDITIONS IMPROVE TO VFR SHORTLY AFTER FRONTAL PASSAGE LATE
TONIGHT ACROSS CENTRAL AND WESTERN AREAS...BUT MAY LINGER TO
AROUND 12Z WED ACROSS E.
WEDNESDAY....HIGH CONFIDENCE VFR BY MID-MORNING FOR ALL OF
SOUTHERN NEW ENGLAND.
KBOS TAF...MODERATE CONFIDENCE IN TAF.
KBDL TAF...MODERATE CONFIDENCE IN TAF.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
WEDNESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE IN MAINLY VFR
CONDITIONS. HOWEVER...BRIEF MARGINAL MVFR CIGS AND PERHAPS A SPOT
RAIN/SNOW SHOWER CAN/T BE RULE OUT WITH COLD POOL ALOFT.
SATURDAY...MODERATE CONFIDENCE. A PERIOD OF MVFR-IFR CONDITIONS
WILL BE POSSIBLE IN SOME RAIN OR SNOW.
&&
.MARINE...
TONIGHT THROUGH TUESDAY NIGHT...HIGH CONFIDENCE.
HIGH SWELLS CONTINUE ACROSS THE OPEN WATERS...BUT ALSO EXPECT S-SW
WIND GUSTS TO PICK UP DURING THE NIGHT. CONVERTED OVER TO A
GENERIC SMALL CRAFT FOR THE OPEN WATERS AS WELL AS VINEYARD SOUND
AND BUZZARDS BAY FOR GUSTS UP TO 25-30 KT DURING TUE/TUE NIGHT.
SEAS WILL REMAIN HIGH...AND WILL BUILD FURTHER ON THE SOUTHERN
WATERS UP TO 7-9 FT.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
MODERATE TO HIGH CONFIDENCE.
COLD ADVECTION WEDNESDAY NIGHT THROUGH FRIDAY WILL RESULT IN
NORTHWEST SCA WIND GUSTS OF 25 TO 30 KNOTS ACROSS THE OPEN WATERS
MUCH OF THE TIME. SCA FOR SEAS ARE ALSO EXPECTED FOR MUCH OF THIS
PERIOD ACROSS THE OUTER WATERS. WINDS AND SEAS WILL TEMPORARILY
DIMINISH FOR A TIME FRI NIGHT/SAT AS COLD AIR ADVECTION DIMINISHES
AND A WEAK WAVE OF LOW PRESSURE MOVES ACROSS THE WATERS.
&&
.HYDROLOGY...
RAINFALL AND SNOW MELT THIS AFTERNOON AND EVENING MAY BE ENOUGH
TO PRODUCE MINOR FLOODING OF SOME SMALL STREAMS AS WELL AS POOR
DRAINAGE FLOODING ACROSS PORTIONS OF MA AND NH WHERE A FLOOD
WATCH HAS BEEN ISSUED. RAINFALL PROJECTED TO APPROACH AN INCH IN
6 TO 8 HOURS. MODELS INDICATE A 40 TO 50 KT LOW LEVEL JET BUT LOW
LEVEL THERMO PROFILE INDICATES THAT ONLY A LITTLE BIT OF THAT WIND
IS LIKELY TO MIX DOWN TO THE SURFACE. THE SNOW PACK ACROSS MOST OF
SOUTHERN NEW ENGLAND IS FAIRLY RIPE WITH TEMPERATURES NEAR
32F. THE EXPECTED RAINFALL WITH DEWPOINTS IN THE MID/UPPER 40S
OUGHT TO RELEASE AT LEAST AN INCH OR SO OF WATER FROM THE
SNOWPACK.
AS FAR AS THE MAINSTEM RIVERS...NERFC GUIDANCE SHOWS ONLY THE
ASSABET AT MAYNARD GOING INTO FLOOD WITH GENERALLY 2+ INCHES OF
RAIN NEEDED TO BRING OTHER FORECAST POINTS INTO FLOOD. EVEN
SO...WE SHOULD KEEP AN EYE ON THE NORTH NASHUA AT FITCHBURG AND
THE SHAWSHEEN. BOTH THE SUDBURY AND PAWTUXET MAY SHOW FAIRLY SHARP
RISES BUT FOR NOW ARE EXPECTED TO REMAIN BELOW FLOOD STAGE UNLESS
SIGNIFICANTLY HEAVIER RAIN AND/OR HIGHER DEWPOINTS OCCUR. SLOW
RISERS SUCH AS THE CHARLES AT DOVER...TAUNTON AT W BRIDGEWATER
WILL LIKELY REMAIN BELOW FLOOD STAGE BUT BECOME ELEVATED AND
SUSCEPTIBLE TO ANY HEAVY RAIN EVENTS IN THE NOT TOO DISTANT
FUTURE. WILL ALSO HAVE TO WATCH THE CONNECTICUT RIVER ONCE LATER
THIS WEEK AS WATER ENTERING THE RIVER FROM NORTHERN NEW ENGLAND
MAKES ITS WAY SOUTH.
THE RAIN THIS AFTERNOON AND EVENING SHOULD BE HEAVY ENOUGH TO
CAUSE LOCALIZED STREET/POOR DRAINAGE FLOODING...ESPECIALLY WHERE
SNOW MIGHT BE BLOCKING CATCH BASINS OR DRAINS. THIS COULD HAVE
SOME IMPACT ON THE EVENING COMMUTE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FLOOD WATCH FROM THIS AFTERNOON THROUGH WEDNESDAY MORNING FOR
MAZ004>006-012>014-017-018-026.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 AM EDT
WEDNESDAY FOR ANZ233-234.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ235-237-
250-251-254>256.
&&
$$
SYNOPSIS...BELK/FRANK
NEAR TERM...BELK
SHORT TERM...BELK
LONG TERM...FRANK
AVIATION...BELK/FRANK
MARINE...FRANK/EVT
HYDROLOGY...THOMPSON/BELK
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
143 AM EDT TUE MAR 12 2013
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT OFFSHORE THROUGH THE EVENING. A COLD FRONT
WILL ADVANCE INTO CENTRAL GEORGIA AND THE CAROLINAS TONIGHT. THE
FRONT WILL MOVE OFF THE COAST TUESDAY MORNING FOLLOWED BY HIGH
PRESSURE THROUGH SATURDAY. A WEAK BACKDOOR COLD FRONT MAY APPROACH
FROM THE NORTH ON SUNDAY AND POSSIBLY LINGER IN THE AREA INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
RAIN CHANCES WILL STEADILY INCREASE FROM WEST-EAST OVERNIGHT AS
THE COLD FRONT DRAWS CLOSER AND SHORTWAVE ENERGY CURRENTLY MOVING
ACROSS THE SOUTHERN MISSISSIPPI VALLEY EJECTS NORTHEAST ACROSS
NORTHERN GEORGIA AND THE SOUTHERN APPALACHIANS. WILL INCREASE POPS
TO 100 PERCENT FOR ALL AREAS TONIGHT WITH THE BULK OF THE HEAVIEST
RAINS LIKELY FALLING BETWEEN MIDNIGHT AND SUNRISE...POSSIBLY A BIT
EARLIER ACROSS FAR INTERIOR SOUTHEAST GEORGIA. GENERALLY USED A
BLEND OF THE HIGHER RESOLUTION H3R AND RAP RUNS TO CONSTRUCT
HOURLY WEATHER PARAMETERS THROUGH 6 AM.
HOURLY TEMPERATURES WILL BE A BIT ATYPICAL WITH THE AREA HOLDING
WELL INTO THE WARM SECTOR UNTIL EARLY TUESDAY MORNING. LOWS WILL
RANGE FROM THE MID 50S ACROSS FAR INTERIOR SOUTHEAST GEORGIA TO
THE LOWER 60S AT THE COAST. MIDNIGHT UPDATE INITIALIZED WITH
SOME MILDER TEMPS IN THE CHARLESTON TRI-COUNTY AREA...65 TO 67
DEGREES EARLY THIS MORNING BEFORE THE RAINS BEGIN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/...
TUESDAY...THERE ARE SOME SLIGHT TIMING DIFFERENCES REGARDING THE
COLD FRONTAL PASSAGE IN THE LATEST 12Z NUMERICAL MODEL
SOLUTIONS...YET EVEN THE SLOWEST SCENARIOS HAVE THE FRONT
OFFSHORE BY MID TO LATE MORNING. WILL THUS CONTINUE TO ADVERTISE
70 TO 80 PERCENT RAIN CHANCES GENERALLY ALONG AND EAST OF
INTERSTATE 95 AT DAYBREAK...WITH POPS 50 PERCENT AND LOWER JUST TO
THE WEST. PRECIPITATION POTENTIAL WILL RAPIDLY DIMINISH BEHIND
THE FRONT AS THE MORNING PROGRESSES...AND HAVE INDICATED ONLY
SLIGHT CHANCES REMAINING FOR THE CHARLESTON TRI COUNTY AREA BY MID
AFTERNOON. TEMPERATURES WILL ONLY BE A FEW DEGREES COOLER THAN
MONDAY...PEAKING FROM 70 TO 72 DEGREES...A COMBINED RESULT OF
DELAYED COLD ADVECTION BEHIND THE FRONT AND THE WARMING EFFECTS OF
INCREASING SUNSHINE AND DOWNSLOPE FLOW. MINIMUM TEMPERATURES
TUESDAY NIGHT WILL REFLECT THE COOLING TREND...FALLING MORE THAN
10 DEGREES LOWER THAN THE PREVIOUS NIGHT...INTO THE 40 DEGREE
RANGE.
WEDNESDAY AND THURSDAY...THE AXIS OF A SHORTWAVE TROUGH WILL SWING
ACROSS THE EAST COAST WEDNESDAY AFTERNOON...AS CENTRAL CANADIAN
HIGH PRESSURE BUILDS INTO THE REGION THROUGH THE LATE WEEK PERIOD.
STRONG COLD ADVECTION WILL INITIATE ACCORDINGLY...AND WHEN COMBINED
WITH LOWERING HEIGHTS ALOFT...WILL SUPPRESS HIGH TEMPERATURES IN
THE MID TO UPPER 60S WEDNESDAY AFTERNOON. BREEZY CONDITIONS ARE
ALSO EXPECTED DURING THE DAYTIME HOURS ON WEDNESDAY...AS DECENT
DIURNAL MIXING TAPS INTO 30 KT BOUNDARY LAYER WINDS. HIGH
TEMPERATURES WILL ACTUALLY BE A DEGREE OR TWO LOWER ON
THURSDAY...WITH WINDS VEERING TOWARD THE NORTH AND DOWNSLOPE
WARMING EFFECTS DIMINISHING. ABUNDANT SUNSHINE AND DRY CONDITIONS
WILL PREVAIL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BROAD UPPER RIDGE WILL SPREAD EAST THURSDAY NIGHT THROUGH
SATURDAY...SUPPORTING A WARMING TREND AND DRY WEATHER.
TEMPERATURES WILL BE BACK INTO THE 70S BY SATURDAY GIVEN CURRENT
TRENDS. UNCERTAINTY INCREASES SUNDAY INTO MONDAY CONSIDERING SOME
DISCREPANCIES IN MEDIUM RANGE MODEL SOLUTIONS. THE LATEST ECMWF IS
STILL SHOWING A PRONOUNCED UPPER TROUGH DIGGING INTO THE CENTRAL
UNITED STATES ON MONDAY...WITH THE 12Z GFS COMING MORE INTO LINE
WITH THIS SCENARIO. HAVE MAINTAINED A DRY EXTENDED FORECAST WITH
ABOVE NORMAL TEMPERATURES...WHILE SHOWING AN INCREASE IN CLOUD
COVER TO ACCOUNT FOR A MORE UNSETTLED PATTERN TOWARD THE END OF
THE PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
RAINS WERE GRADUALLY ON THE INCREASE TO THE SW AND W OF THE TERMINALS
AT 06Z. MVFR CIGS/VSBYS SHOULD DEVELOP TOWARD 09Z THIS MORNING WITH
A CHANCE OF IFR CIGS 10Z-14Z JUST AHEAD OF THE COLD FRONT. WE HAVE
CONTINUED SIMILAR TIMING TO OUR PREVIOUS TAF SET AND ALLOW FOR
CLEARING CONDITIONS THIS AFTERNOON WITH A RETURN TO VFR CONDITIONS
AFTER MVFR OR LOWER CIGS AND VSBYS WITH THE FRONTAL RAINS A FEW
HOURS EITHER SIDE OF DAYBREAK THIS MORNING. PERIODS OF BREEZY
CONDITIONS WITH W WINDS THIS AFTERNOON GUSTING OVER 20 KT AT TIMES.
EXTENDED AVIATION OUTLOOK...MAINLY VFR CONDITIONS EXPECTED TO
PERSIST THROUGH THE PERIOD.
&&
.MARINE...
OVERNIGHT...STRONGEST WINDS OUTSIDE THE CHILLY SHELF WATERS AND
EVEN OVER LAND-BASED AREAS WHERE TEMPS IN THE MID/UPPER 60S. THE
SMALL CRAFT ADVISORY OVER NEAR SHORE GEORGIA WATERS LOOKS QUITE
MARGINAL GIVEN 4 FT SEAS AT GRAYS REEF...S FLOW AND FORECAST WAVE
TRAJECTORIES...BUT WILL LET IT RIDE OVERNIGHT GIVEN THE VARIOUS
UNCERTAINTIES.
WINDS AND SEAS FOR THE NEARSHORE WATERS WILL DIMINISH NO LATER
THAN TUESDAY AFTERNOON AS THE COLD FRONT PUSHES OFFSHORE...WHILE
SEAS MAINTAIN ADVISORY CONDITIONS ACROSS THE OUTER GEORGIA WATERS.
COLD ADVECTION WILL BE SLIGHTLY DELAYED BEHIND THE FRONT...WITH
THE MAIN SURGE EXPECTED MORE TOWARD WEDNESDAY. THE DEEPEST MIXING
WILL BE ACROSS THE WARMER OFFSHORE WATERS...MAINLY BEYOND 20 NM
FROM THE COAST. THUS THE OUTER GEORGIA MARINE ZONES WILL REMAIN
UNDER A SMALL CRAFT ADVISORY THROUGH THURSDAY. FREQUENT GUSTS UP
TO 25 KT ACROSS PORTIONS OF THE NEARSHORE WATERS COULD NECESSITATE
ADVISORIES FOR THOSE AREAS AS WELL. MUCH WEAKER FLOW EXPECTED
THURSDAY INTO THE WEEKEND AS HIGH PRESSURE BUILDS FROM THE
WEST/NORTHWEST.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR AMZ350-
352.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT THURSDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ354.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...79
LONG TERM...79
AVIATION...
MARINE...ST
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1058 PM MDT MON MAR 11 2013
.UPDATE...
ISSUED AT 1004 PM MDT MON MAR 11 2013
JUST COMPLETED AN UPDATE TO ADJUST FOR THE AREA OF SNOW. VERY
NARROW BAND OF LIGHT TO POSSIBLY MODERATE SNOWFALL IN LEFT FRONT
QUADRANT AND MODERATE FRONTOGENESIS. THE SNOWFALL AND THE LIFT
MOVE SOUTHEAST OR REMAINS TIED TO HIGHER TO THE WEST. THE LIFT AND
SNOWFALL WEAKENS WITH TIME PER THE MODEL WORLD AND LATEST RADAR
TRENDS WOULD SUPPORT THAT. SO KEPT THE HIGHEST POPS IN THE
SOUTHWEST AND RAPIDLY DECREASE THEM FROM 06Z TO 09Z. ACCUMULATIONS
WILL BE AN INCH OR LESS. REMAINDER OF THE FORECAST LOOKS FINE.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1215 PM MDT MON MAR 11 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS INDICATE NW FLOW IN PLACE
ACROSS PLAINS WITH TROUGH OVER GREAT LAKES AND RIDGE BUILDING ALONG
WEST COAST. SEVERAL WEAK SHORTWAVES WITHIN THE MEAN FLOW HAVE LEAD
TO DEVELOPMENT OF HIGH CLOUDS ACROSS THE REGION.
PRIMARY FORECAST CONCERN FOR SHORT TERM WILL BE POTENTIAL FOR LIGHT
SNOW LATE TONIGHT ACROSS THE CWA. A FAST MOVING SHORTWAVE TROUGH
OVER THE NORTHERN PLAINS WILL SHIFT SOUTH THIS EVENING AND OVER THE
CWA TONIGHT. LARGE SCALE FORCING IS ADVERTISED ACROSS THE CENTRAL
PART OF THE CWA...WITH MOISTURE PROFILES SATURATING LATER THIS
EVENING. THERE IS GOOD MODEL OVERLAP IN TIMING OF QPF FROM WEST TO
EAST THROUGH THE EVENING AND OVERNIGHT...WITH PRECIP STARTING AS
RAIN LATE THIS AFTERNOON OVER EASTERN COLORADO AND TRANSITIONING TO
ALL SNOW THIS EVENING. WITH INCREASING CONFIDENCE IN MEASURABLE
PRECIP I INCREASED POPS TO LIKELY CATEGORY ACROSS THE CENTRAL PART
OF THE CWA IN LINE WITH MODEL CONSENSUS. THERE IS STILL WEAK
INSTABILITY ADVERTISED WITH SNOW BAND...AND WITH STRONG FRONTOGENESIS
IMMEDIATELY BEHIND SHORTWAVE WE COULD SEE NARROW BANDING. QPF AMOUNTS
ARE GENERALLY LIGHT...AND WITH MARGINAL MOISTURE ADVECTION AND THE
FAST NATURE OF THIS SYSTEM I AM ONLY ANTICIPATING AROUND ONE INCH OF
SNOWFALL AT THE MOST. ANY LINGERING SNOW SHOULD QUICKLY COME TO AN
END AROUND SUNRISE TUESDAY MORNING.
DRY CONDITIONS ARE THEN EXPECTED THROUGH THE REST OF THE DAY TUESDAY
WITH ONLY HIGH CLOUDS POSSIBLY LINGERING THROUGH THE DAY. AIR MASS
SHOULD BE COOLER THAN TODAY...THOUGH IMPACTS FROM SNOW PACK SHOULD
BE MINIMAL. WE COULD SEE IMPACT FROM SKY COVER...BUT FOR NOW I KEPT
FORECAST SIMILAR TO TODAY...WITH MID/UPPER 40S IN THE NORTHEAST TO
LOW 50S IN THE SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 PM MDT MON MAR 11 2013
FORECAST CONCERN IN THE LONG TERM PERIOD IS THE POSSIBILITY OF
PRECIPITATION THIS WEEKEND.
THE AXIS OF THE BROAD UPPER RIDGE TRANSLATES FROM THE WEST COAST
TO THE INTERMOUNTAIN AND ROCKY MOUNTAIN REGION BETWEEN TUESDAY
NIGHT AND THURSDAY NIGHT. BY FRIDAY THE RIDGE BEGINS TO FLATTEN AS
SEVERAL SHORT WAVE TROUGH BEGIN TO RIDE UP OVER THE APEX OF THE
RIDGE. THESE WAVES ARE EXPECTED TO REMAIN NORTH OF THE CENTRAL
HIGH PLAINS REGION THROUGH AT LEAST SATURDAY MORNING.
THEREFORE...THE FORECAST AREA IS EXPECTED TO REMAIN DRY AND WARM
THROUGH SATURDAY NIGHT WITH A PERSISTENT LEE TROUGH REMAINING IN
PLACE IN THE VICINITY OF THE EASTERN COLORADO BORDER AREA.
EARLY SATURDAY...IT APPEARS THAT A COOLER AREA OF HIGH PRESSURE
WILL MOVE SOUTHWARD ACROSS THE PLAINS STATES WITH A BACKDOOR COLD
FRONT PUSHING INITIALLY INTO THE EASTERN PORTION OF THE FORECAST
AREA WITH COOLER AIR REMAINING GENERALLY IN PLACE ACROSS THE
PLAINS THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF
NEXT WEEK. THE GFS AND ECMWF ARE NO LONGER COMPLETELY OUT OF PHASE
WITH EACH OTHER AT THIS POINT...BUT CONTINUE TO OFFER SOMEWHAT
DIFFERENT SOLUTIONS WITH THE NEXT UPPER TROUGH ENTERING THE
PACIFIC NORTHWEST AND TRACKING EAST OF THE ROCKIES SOMETIME IN THE
SUNDAY TO SUNDAY NIGHT TIME FRAME. WITH SEVERAL SMALLER SHORT WAVE
TROUGHS PRECEDING THE MAIN UPPER TROUGH AND WITH THE APPROACH AND
PASSAGE OF THE MAIN UPPER TROUGH...EXPECT AT LEAST A SLIGHT CHANCE
OF PRECIPITATION OVER THE FORECAST AREA FROM LATE SATURDAY THROUGH
AT LEAST SUNDAY NIGHT AND POSSIBLY THE DAY ON MONDAY...DEPENDING
UPON THE MODEL SOLUTION THAT ENDS UP CLOSER TO REALITY. HAVE
THEREFORE GONE WITH A FAIRLY BROAD BRUSHED SOLUTION THROUGH THE
WEEKEND AND INTO MONDAY WITH A SLIGHT CHANCE OF LIGHT RAIN WITH
LIGHT ACCUMULATIONS DURING THAT TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1055 PM MDT MON MAR 11 2013
VFR CONDITIONS ARE EXPECTED AT BOTH SITES. MAIN AREA OF SNOW HAS
MOVED SOUTH AND EAST OF KGLD. SOME VERY LIGHT SNOW COULD OCCUR
VERY EARLY IN THE PERIOD WITH LITTLE TO NO VISIBILITY RESTRICTIONS.
SNOW WILL REMAIN WELL SOUTH OF KMCK. OTHERWISE...CEILINGS WILL
GRADUALLY RISE WITH CLEARING SKIES BY LATE TO MID MORNING. AFTER
CLEARING OCCURS AND THE SUN COMES UP...NORTHWEST WINDS WILL
INCREASE AND BECOME GUSTY UNTIL LATE IN THE AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1011 PM MDT MON MAR 11 2013
.UPDATE...
ISSUED AT 1004 PM MDT MON MAR 11 2013
JUST COMPLETED AN UPDATE TO ADJUST FOR THE AREA OF SNOW. VERY
NARROW BAND OF LIGHT TO POSSIBLY MODERATE SNOWFALL IN LEFT FRONT
QUADRANT AND MODERATE FRONTOGENESIS. THE SNOWFALL AND THE LIFT
MOVE SOUTHEAST OR REMAINS TIED TO HIGHER TO THE WEST. THE LIFT AND
SNOWFALL WEAKENS WITH TIME PER THE MODEL WORLD AND LATEST RADAR
TRENDS WOULD SUPPORT THAT. SO KEPT THE HIGHEST POPS IN THE
SOUTHWEST AND RAPIDLY DECREASE THEM FROM 06Z TO 09Z. ACCUMULATIONS
WILL BE AN INCH OR LESS. REMAINDER OF THE FORECAST LOOKS FINE.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1215 PM MDT MON MAR 11 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS INDICATE NW FLOW IN PLACE
ACROSS PLAINS WITH TROUGH OVER GREAT LAKES AND RIDGE BUILDING ALONG
WEST COAST. SEVERAL WEAK SHORTWAVES WITHIN THE MEAN FLOW HAVE LEAD
TO DEVELOPMENT OF HIGH CLOUDS ACROSS THE REGION.
PRIMARY FORECAST CONCERN FOR SHORT TERM WILL BE POTENTIAL FOR LIGHT
SNOW LATE TONIGHT ACROSS THE CWA. A FAST MOVING SHORTWAVE TROUGH
OVER THE NORTHERN PLAINS WILL SHIFT SOUTH THIS EVENING AND OVER THE
CWA TONIGHT. LARGE SCALE FORCING IS ADVERTISED ACROSS THE CENTRAL
PART OF THE CWA...WITH MOISTURE PROFILES SATURATING LATER THIS
EVENING. THERE IS GOOD MODEL OVERLAP IN TIMING OF QPF FROM WEST TO
EAST THROUGH THE EVENING AND OVERNIGHT...WITH PRECIP STARTING AS
RAIN LATE THIS AFTERNOON OVER EASTERN COLORADO AND TRANSITIONING TO
ALL SNOW THIS EVENING. WITH INCREASING CONFIDENCE IN MEASURABLE
PRECIP I INCREASED POPS TO LIKELY CATEGORY ACROSS THE CENTRAL PART
OF THE CWA IN LINE WITH MODEL CONSENSUS. THERE IS STILL WEAK
INSTABILITY ADVERTISED WITH SNOW BAND...AND WITH STRONG FRONTOGENESIS
IMMEDIATELY BEHIND SHORTWAVE WE COULD SEE NARROW BANDING. QPF AMOUNTS
ARE GENERALLY LIGHT...AND WITH MARGINAL MOISTURE ADVECTION AND THE
FAST NATURE OF THIS SYSTEM I AM ONLY ANTICIPATING AROUND ONE INCH OF
SNOWFALL AT THE MOST. ANY LINGERING SNOW SHOULD QUICKLY COME TO AN
END AROUND SUNRISE TUESDAY MORNING.
DRY CONDITIONS ARE THEN EXPECTED THROUGH THE REST OF THE DAY TUESDAY
WITH ONLY HIGH CLOUDS POSSIBLY LINGERING THROUGH THE DAY. AIR MASS
SHOULD BE COOLER THAN TODAY...THOUGH IMPACTS FROM SNOW PACK SHOULD
BE MINIMAL. WE COULD SEE IMPACT FROM SKY COVER...BUT FOR NOW I KEPT
FORECAST SIMILAR TO TODAY...WITH MID/UPPER 40S IN THE NORTHEAST TO
LOW 50S IN THE SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 PM MDT MON MAR 11 2013
FORECAST CONCERN IN THE LONG TERM PERIOD IS THE POSSIBILITY OF
PRECIPITATION THIS WEEKEND.
THE AXIS OF THE BROAD UPPER RIDGE TRANSLATES FROM THE WEST COAST
TO THE INTERMOUNTAIN AND ROCKY MOUNTAIN REGION BETWEEN TUESDAY
NIGHT AND THURSDAY NIGHT. BY FRIDAY THE RIDGE BEGINS TO FLATTEN AS
SEVERAL SHORT WAVE TROUGH BEGIN TO RIDE UP OVER THE APEX OF THE
RIDGE. THESE WAVES ARE EXPECTED TO REMAIN NORTH OF THE CENTRAL
HIGH PLAINS REGION THROUGH AT LEAST SATURDAY MORNING.
THEREFORE...THE FORECAST AREA IS EXPECTED TO REMAIN DRY AND WARM
THROUGH SATURDAY NIGHT WITH A PERSISTENT LEE TROUGH REMAINING IN
PLACE IN THE VICINITY OF THE EASTERN COLORADO BORDER AREA.
EARLY SATURDAY...IT APPEARS THAT A COOLER AREA OF HIGH PRESSURE
WILL MOVE SOUTHWARD ACROSS THE PLAINS STATES WITH A BACKDOOR COLD
FRONT PUSHING INITIALLY INTO THE EASTERN PORTION OF THE FORECAST
AREA WITH COOLER AIR REMAINING GENERALLY IN PLACE ACROSS THE
PLAINS THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF
NEXT WEEK. THE GFS AND ECMWF ARE NO LONGER COMPLETELY OUT OF PHASE
WITH EACH OTHER AT THIS POINT...BUT CONTINUE TO OFFER SOMEWHAT
DIFFERENT SOLUTIONS WITH THE NEXT UPPER TROUGH ENTERING THE
PACIFIC NORTHWEST AND TRACKING EAST OF THE ROCKIES SOMETIME IN THE
SUNDAY TO SUNDAY NIGHT TIME FRAME. WITH SEVERAL SMALLER SHORT WAVE
TROUGHS PRECEDING THE MAIN UPPER TROUGH AND WITH THE APPROACH AND
PASSAGE OF THE MAIN UPPER TROUGH...EXPECT AT LEAST A SLIGHT CHANCE
OF PRECIPITATION OVER THE FORECAST AREA FROM LATE SATURDAY THROUGH
AT LEAST SUNDAY NIGHT AND POSSIBLY THE DAY ON MONDAY...DEPENDING
UPON THE MODEL SOLUTION THAT ENDS UP CLOSER TO REALITY. HAVE
THEREFORE GONE WITH A FAIRLY BROAD BRUSHED SOLUTION THROUGH THE
WEEKEND AND INTO MONDAY WITH A SLIGHT CHANCE OF LIGHT RAIN WITH
LIGHT ACCUMULATIONS DURING THAT TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 544 PM MDT MON MAR 11 2013
VFR TO MVFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT MCK AND
GLD. LIGHT RAIN AND SNOW SHOWERS DEVELOPED OVER NORTHEAST COLORADO
LATE THIS AFTERNOON AND WILL CONTINUE TO MOVE EAST AS A WEAK
SHORTWAVE TROUGH MOVES THROUGH THE CENTRAL HIGH PLAINS. CURRENT
GUIDANCE LINES UP WELL WITH CURRENT WEATHER AS DEPICTED ON RADAR
AND VERIFIED WITH SURFACE OBSERVING SITES. COULD SEE AN HOUR OR
TWO OF IFR CONDITIONS AT GLD...BUT HAVE STRONG CONFIDENCE THAT
THIS EVENT WILL REMAIN VFR/MVFR. CEILINGS WILL BE MORE OF A
CONCERN THAN VISIBILITY FOR MOST OF THE PERIOD...WITH MVFR VIS
EXPECTED DURING THE PERIODS OF SNOW. WINDS WILL BE LIGHT DURING
THE EVENT OUT OF THE NORTH-NORTHWEST. LIGHT SNOW SHOWERS SHOULD
TAPER OFF AROUND 08Z AT GLD AND 10Z AT MCK GIVING WAY TO A BREEZY
CONDITIONS TOMORROW WITH NORTHWEST WINDS GUSTING TO 25KTS OR SO.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
810 PM EDT WED MAR 13 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 421 PM EDT WED MAR 13 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF/
CLOSED UPR LO CENTERED JUST S OF JAMES BAY MOVING STEADILY TO THE
E...ALLOWING A RDG OVER THE ROCKIES TO EXPAND TO THE E...WITH
00Z-12Z H3 HGT RISES UP TO 150M EVIDENT OVER THE NRN PLAINS/UPR MS
RIVER VALLEY. ALTHOUGH A STEADY NNW FLOW BTWN ASSOCIATED SFC LO OVER
SE CANADA AND HI PRES RDG AXIS STRETCHING FM NW ONTARIO INTO THE
CENTRAL PLAINS IS PUSHING H85 TEMPS AS LO AS -13C TO -15C INTO THE
UPR LKS...THE AIRMASS IMMEDIATELY UPSTREAM IS SO DRY PER 12Z INL
RAOB THAT THERE ARE NO -SHSN OR EVEN MUCH IN THE WAY OF LK CLDS OVER
UPR MI ATTM. LOOKING A BIT FARTHER TO THE NW...THERE WAS SOME SC
NOTED EARLIER OVER PORTIONS OF NW ONTARIO ASSOCIATED WITH A BIT MORE
MSTR SHOWN ON THE 12Z YPL RAOB...BUT SUBSIDENCE ASSOCIATED WITH THE
APRCHG H3 HGT RISES/SFC ACYC FLOW AS WELL AS SOME DAYTIME HEATING
HAS CAUSED THIS CLD TO DISSIPATE. FARTHER TO THE NW...A SHRTWV
MOVING THRU ALBERTA AND INTO SASKATCHEWAN IS ROUNDING THE UPR RDG
OVER THE ROCKIES. MID/HI CLDS AHEAD OF THIS DISTURBANCE AND
ASSOCIATED WARM FNT OVER THE HI PLAINS ARE PUSHING E THRU THE
DAKOTAS/SCENTRAL CANADA THIS AFTN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/IMPACT ON TEMPS.
TNGT...ALTHOUGH LK CLDS HAVE DISSIPATED WITH ARRIVAL OF DRIER AIR/
DAYTIME HEATING WITH HIER MARCH SUN ANGLE THAT TENDS TO CAUSE
SUBSIDENCE OVER LK SUP...CONCERNED SOME CLDS WL REFORM THIS EVNG
WITH LOSS OF HEATING/ARRIVAL OF MSTR NOTED IN NW ONTARIO IN THE
PRESENCE OF H85 TEMPS NEAR -12C AND THEN SPREAD INLAND INTO MAINLY
THE NCENTRL AND ERN CWA IN NW FLOW AHEAD OF APRCHG HI PRES RDG AXIS.
BUT AS THE HI PRES RDG AXIS APRCHS FM THE W...INCRSG SUBSIDENCE/MORE
ACYC LLVL FLOW IS FCST TO SINK THE SUBSIDENCE INVRN LO ENUF ANY LO
CLD SHOULD DSPT W-E. ALTHOUGH FCST H85 TEMPS ARE MARGINAL FOR LES...
LO INVRN BASE 2-3K FT AGL WL LIMIT LES TO PERHAPS SOME FLURRIES OVER
THE ERN ZNS DOWNWIND OF THE LK IN LLVL NW FLOW. PREVIOUS FCST HAD A
REASONABLE HANDLE ON THESE EXPECTATIONS...SO MADE FEW CHANGES TO
THESE GRIDS. SOME MID/HI CLDS WELL IN ADVANCE OF APRCHG SHRTWV/WARM
FNT TO THE W ARE FCST TO MOVE INTO THE WRN ZNS LATE TNGT. BUT WITH A
PERIOD OF MAINLY CLR SKIES/LGT WINDS...WL MAINTAIN MIN TEMPS FCST
NEAR LO END OF GUIDANCE OVER MUCH OF THE INTERIOR W HALF.
THU...SHRTWV NOW MOVING THRU SCENTRAL CANADA OVER TOP OF ROCKIES RDG
IS FCST TO MOVE THRU NW ONTARIO. ALTHOUGH CLD WL OVERSPREAD UPR MI
W-E AHEAD OF THE WARM FNT...PASSAGE OF SHARPER DPVA/DEEP LYR QVECTOR
CNVGC TO THE N CLOSER TO TRACK OF DISTURBANCE AS WELL AS LIMITED
DEPTH OF ABSOLUTE MSTR RETURN SHOULD RESULT IN A DRY DAY. H85 TEMPS
ARE FCST TO RISE TO BTWN ABOUT -2C OVER THE W AND -8C OVER THE E BY
00Z FRI AS A SW FLOW DVLPS ON THE WRN FLANK OF RETREATING HI PRES...
SO EXPECT A WARMER DAY ESPECIALLY OVER THE W HALF.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 421 PM EDT WED MAR 13 2013
UPPER LEVEL PATTERN STARTS OFF LONG TERM WITH ELONGATED TROUGH OVER
MOST OF NORTHERN AND EASTERN CANADA AND RIDGING OVER WESTERN CANADA.
OVER TIME RIDGE IS FLATTENED AS TROUGHING OVR CANADA SETTLES INTO
NORTHERN TIER OF CONUS THROUGH THE UPCOMING WEEKEND. ZONAL WNW FLOW
RESULTS AND WILL BRING STRONGER SHORTWAVE ACROSS NORTHERN PLAINS AND
UPPER GREAT LAKES THURSDAY NIGHT AND FRIDAY. TRICKY SYSTEM WITH
REGARD TO NORTHERN EXTENT OF HEAVIER SNOW. AS ALLUDED TO YDY...WILL
GREATLY DEPEND ON HOW FAR SOUTH SFC-H85 BAROCLINIC ZONE ALLIGNS IN
WAKE OF NORTHERN STREAM SHORTWAVE MOVING THROUGH THURSDAY NIGHT. GFS
AND GEM-NH FARTHER SOUTH /12Z GFS TRENDED EVEN FARTHER SOUTH/ WHILE
NAM IS MUCH FARTHER NORTH. ECMWF/UKMET A COMPROMISE...BUT THE ECMWF
DID TREND FARTHER SOUTH COMPARED TO THE 12Z RUN FROM YDY/12 MARCH.
SEEMS LIKE THE NAM IS BECOMING MORE OF A NORTHERN OUTLIER...SO WILL
TEND TO TREND AWAY FROM THAT IDEA AND ANY MODELS THAT ARE
INITIALIZED OFF OF IT SUCH AS OUR LOCAL WRF. STILL THINK THAT THE
LOCATION OF TIGHTER LOW-LEVEL TEMPERATURE GRADIENT WILL BE
ULTIMATELY WHERE HEAVIEST QPF/SNOW SETS UP ON FRIDAY AS SHORTWAVE
AND SFC-H85 LOWS MOVE IN FROM NORTHERN PLAINS.
WHERE THE TIGHT THERMAL GRADIENT OCCURS THERE IS A POTENTIAL FOR A
NARROW STRIPE OF HEAVY SNOW DUE TO LOW-MID LEVEL FRONTOGENESIS AMD
DIVERGENCE ALOFT FROM RIGHT ENTRANCE REGION OF JET STREAK DROPPING
INTO GREAT LAKES FROM ONTARIO ALONG WITH DECENT MOISTURE ADVECTION
WITH H7 MIXING RATIOS 3-4G/KG. SFC-H85 LOWS/LOW-LEVEL FLOW IS
SHOWING A STRENGTHENING TREND OVERALL AS WELL. BASED ON MODEL
CONSENSUS...SEEMS LIKE BETTER CHANCE FOR ENHANCEMENT/HEAVIER SNOW TO
COME TOGETHER MAY END UP JUST TO OUR SOUTH. WILL KEEP POPS LIKELY
TOWARD THE WEST AND SOUTH...WHERE MODEL AGREEMENT IS HIGHER THAT
SNOW OCCURS. MAY NEED HEADLINES...LIKELY ADVISORIES...IN THESE AREAS
FRIDAY INTO FRIDAY EVENING. WWD DAY2 GRAPHICS INDICATE SWATH OF 2-4
INCHES OF SNOW FRIDAY ALONG WI BORDER...WITH JUST A COUPLE INCHES
OVER NORTHERN UPR MICHIGAN. BASED ON CROSS SECTIONS FROM GFS AND
JUST THE LOOK FROM QPF FIELDS...COULD BE A VERY SHARP CUTOFF TO SNOW
ON NORTH SIDE. AS AGEOSTROPIC CIRCULATION WITHIN H85-H7 FRONTOGENEIS
OCCURS THERE ARE INDICATIONS THAT SUBSIDENCE AREA OVER NORTHERN UPR
MICHIGAN WILL DRAW INCREASINGLY DRIER AIR IN FROM CANADA. GRADIENT
OF SNOW AMOUNTS MAY END UP SIMILAR TO SNOW EVENT FROM LATE MARCH OF
2011 THAT IMPACTED FAR SOUTH CENTRAL CWA WITH OVER A FOOT OF SNOW
WHILE NORTHERN CWA ONLY SAW FLURRIES. WE SHALL SEE. ONCE SNOW TAPERS
OFF...DESPITE SUFFICIENT COLD AIR IN LOW-LEVELS...UNSURE ON EXTENT
OF LK EFFECT GIVEN CONCERNS WITH THE DRY AIR.
FAIRLY QUIET LATER FRIDAY NIGHT INTO SATURDAY MORNING. MAY SEE SOME
SNOW SHOWERS FLARE UP SATURDAY AFTN INTO SATURDAY NIGHT WITH ARRIVAL
OF SHORTWAVE/COLD AIR ADVECTION DRIVING H85 TEMPS DOWN TO NEAR -20C.
MODELS HINT AT SHARPER LOW-LEVEL TROUGH MOVING THROUGH SATURDAY
EVENING WHICH MAY ALSO ENHANCE THE SNOW. INCREASED POPS A BIT INTO
SATURDAY NIGHT. GIVEN FAVORABLE LOCATION OF DGZ WITHIN MOIST LAYER
PRESENT WITH LAKE EQLS UP TO 10KFT...MAY SEE SEVERAL INCHES OF
FLUFFY SNOW ALONG LK SUPERIOR. INVERSION LOWERS BLO 5KFT THROUGH
DAY ON SUNDAY...BUT ENOUGH COLD AIR LINGERS FOR NW FLOW AREAS TO SEE
SCT LK EFFECT SNOW SHOWERS.
ATTN THEN TURNS TO SHORTWAVE TROUGHING DIGGING ACROSS ROCKIES BY
SUNDAY HELPING TO DEEPEN SFC LOW ON THE LEE SIDE OF THE ROCKIES.
UPPER TROUGH/SFC LOW IS FORECAST TO HEAD EAST AND DEEPEN AS
SHORTWAVE IN THE NORTHERN BRANCH ATTEMPTS TO PHASE WITH THE SOUTHERN
STREAM SYSTEM. SFC LOW DEEPENS FURTHER AND LIFTS ACROSS GREAT LAKES
WHICH MAY LEAD TO A SIGNIFICANT SNOW STORM OVER PORTIONS OF THE
UPPER GREAT LAKES. UP TO 12Z THERE WAS ACTUALLY GOOD AGREEMENT FROM
THE ECMWF AND GFS ON TRACK OF THE LOW. 12Z ECMWF JOGGED FARTHER WEST
THOUGH IT WOULD STILL BE MAINLY A SNOW EVENT. WAVES PRODUCING THIS
WEATHER SYSTEM ARE STILL WELL TO THE NORTH...UNDERSTATEMENT...OVER
THE NORTHWEST TERRITORIES OF CANADA...AND IN THE VCNTY OF THE NORTH
POLE. THERE IS A LOT OF INTERACTION THAT HAS TO OCCUR YET BTWN THESE
WAVES...AND LIKELY OTHERS AS WELL...BEFORE A FINAL SOLUTION IS
DETERMINED. CERTAINLY A SYSTEM TO WATCH THOUGH AS IT WILL HAVE GULF
MOISTURE TO WORK ON. CONVECTION TO THE SOUTH TOO SO THAT INTERACTION
WILL NEED TO BE ADDRESSED BY MODELS AS WELL. MID SHIFT PUT A MENTION
IN HWO...WHICH SEEMS LIKE GOOD CALL IN THIS SITUATION. STRONGER
SYSTEM DRAWS DOWN CONTINUAL COLD AIR ACROSS LK SUPERIOR THROUGH
MIDWEEK SO PUT CHANCE POPS IN OVER NORTHERN CWA. LAST PANELS OF GFS
AND ECMWF INDICATE SOME POTENTIAL FOR MODERATING TEMPS TOWARD LAST
WEEK OF MARCH AS MEAN TROUGH ATTEMPTS TO SHIFT INTO EASTERN CANADA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 809 PM EDT WED MAR 13 2013
SATELLITE TRENDS AND LOW LEVEL WINDS FCST SUGGEST THAT LAKE EFFECT
CLOUDS WILL REMAIN WEST OF BOTH CMX AND SAW. AS A HIGH PRES RIDGE
BUILDS INTO THE REGION...EXPECT THAT THE SUBSIDENCE INVERSION WILL
LOWER ENOUGH TONIGHT TO DISSIPATE ANY LOWER CLOUDS THAT DO FORM.
ALTHOUGH SOME MID/HI CLOUDS WILL SPREAD ACROSS THE AREA ON THU...
PREVAILING DRY LOW LEVEL AIR WILL RESULT IN VFR CONDITIONS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EDT WED MAR 13 2013
AS HI PRES RIDGE AXIS MOVES IN FROM THE W TONIGHT...THE PRES
GRADIENT WILL WEAKEN OVER LAKE SUP...CAUSING NNW WINDS UP TO 30 KTS
LATE THIS AFTERNOON OVER THE E HALF TO DIMINISH AND FREEZING SPRAY
TO END. WINDS WILL SHIFT TO THE SW ON THU AS THE RIDGE AXIS MOVES TO
THE E...BUT WINDS WILL BE UNDER 20 KTS UNTIL LATE IN THE DAY OVER
THE W AS ANOTHER TROF APPROACHES FROM THE NW AND SHARPENS THE PRES
GRADIENT.
DUE TO THAT TIGHTER PRESSURE GRADIENT...W WINDS TO 25 KTS INCREASE TO
30 KTS WHILE SHIFTING N-NW ON THU NIGHT. SLIGHT RISK THAT GALE GUSTS
COULD OCCUR RIGHT IN WAKE OF THE WIND SHIFT THURSDAY EVENING OVER
EASTERN LK SUPERIOR. EXPECT N-NE WINDS TO 25 KTS THROUGH FRI AS LOW
PRESSURE PASSES SOUTH OF THE REGION. AFTER LIGHTER WINDS INTO SAT
MORNING ANOTHER TROUGH WILL SHIFT WINDS TO NW TO 25 KTS SAT NIGHT.
WINDS DIMINISH ON SUN BUT INCREASE YET AGAIN LATE ON MON AS STRONG
LOW PRESSURE SYSTEM LIFTS ACROSS THE UPR LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...JLB
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
414 PM EDT TUE MAR 12 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE MAR 12 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF
CENTERED OVER THE GREAT LKS BTWN UPR RDGS ALONG THE W COAST AND OFF
THE E COAST. WITH DEEP CYC NW FLOW...ABUNDANT MSTR SHOWN ON THE 12Z
GRB RAOB...AND H85 TEMPS IN THE -13C TO -16C RANGE...SHSN HAVE BEEN
COMMON OVER THE CWA TODAY UNDER CLDY SKIES...ESPECIALLY NEAR LK SUP
IN AREAS FAVORED BY THE NW LLVL FLOW. THE SN HAS BEEN RATHER FLUFFY
AS MODEL SDNGS INDICATE THE DGZ IS SEVERAL THOUSAND FEET DEEP GIVEN
FVRBL H85 TEMPS. THERE IS A SHRTWV DROPPING SEWD THRU MN ACCOMPANIED
BY A FAIRLY WELL DEFINED TROF AT H85-7. UPSTREAM OBS AT GRAND MARAIS
ON THE MN NORTH SHORE AND AT THUNDER BAY IN ONTARIO INDICATE SOME
HEAVIER SHSN ACCOMPANY THIS TROF PASSAGE FARTHER TO THE E-SE AWAY FM
DRIER AIR SHOWN ON THE 12Z INL/YPL RAOBS. APRCHG FCST ISSUANCE...
SOME OF THE HEAVIER SHSN HAVE ARRIVED OVER THE WRN COUNTIES. CMX HAS
REPORTED VSBY DOWN TO 1/4SM AT TIMES...AND REPORTS FM GOGEBIC COUNTY
INDICATE AS MUCH AS 5 INCHES OF SN FELL THERE THRU 18Z.
LATE THIS AFTN/TNGT...AS SHRTWV IN MN DIGS SEWD...GUIDANCE SHOWS
PRONOUNCED H85 WSHFT ASSOCIATED WITH TROF PASSAGE AS WELL AS AREA OF
H85-5 QVECTOR CNVGC CROSSING THE CWA NW-SE. EXPECT SHSN TO INCRS IN
INTENSITY WITH THIS ENHANCED SUPPORT IN PRESENCE OF DEEP MSTR. FCST
SDNGS CONTINUE TO SHOW UVV FOCUSED IN THE DGZ...SO EXPECT HI SN/
WATER RATIOS AOA 20:1. LATER TNGT IN THE WAKE OF THE TROF PASSAGE...
DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE OF THE SHRTWV/TROF WL
CONSPIRE TO LOWER INVRN BASES DOWN TO 2-3K FT AGL. WITH ARRIVAL OF
LLVL DRY AIR SHOWN ON THE 12Z INL/YPL RAOBS...EXPECT LES TO DIMINISH
FAIRLY STEADILY AFT 06Z. OVERALL...SHIFTING WINDS FM NW TO N AND
LIMITED 6-9HR WINDOW OR SO FOR HEAVIER SHSN WL LIMIT TOTAL SN
FALL...SO EXPECT SN TOTALS TO REMAIN WITHIN ADVY LIMITS DESPITE
FVRBL SN/WATER RATIOS. THGE ONLY EXCEPTION IS OVER THE FAR W...WHERE
SOME HEAVY SN FELL DURING THE AFTN AS NOTED ABV. SINCE THERE WL BE
PERIODS OF +SHSN THRU THIS EVNG IN THAT AREA WITH SOME FOCUSED LLVL
CNVGC IN FVRBL CYC NNW FLOW...OPTED TO UPGRADE ADVY TO A WARNING FOR
GOGEBIC/ONTONAGON COUNTIES. ALSO EXTENDED ADVY OVER THE ERN ZNS THRU
12Z GIVEN MORE PERSISTENT FORCING/DEEPER MSTR THERE.
WED...AXIS OF MUCH DRIER AIR WITH H85 DEWPTS AS LO AS -40C AS WELL
AS DEEP LYR QVECTOR DVGC/SUBSIDENCE UNDER STEADILY RISING H5 HGTS
FOLLOWING SHIFT OF UPR TROF AXIS TO THE E WL RESULT IN MAINLY DRY WX
AFTER LINGERING SHSN OVER MAINLY THE E DIMINISH IN THE MRNG. IN
FACT...FCST SDNGS SUG SKIES MAY TURN MOSUNNY IN THE AFTN...
ESPECIALLY NEAR LK SUP WITH A TENDENCY FOR CLRG OVER THE WATER UNDER
STRENGTHENING LATE WINTER SUNSHINE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 PM EDT TUE MAR 12 2013
TO START THE LONG TERM PERIOD...OVERVIEW OF LARGE SCALE FEATURES
TROUGH OVER GREAT LAKES AND EASTERN CANADA WITH BROAD RIDGING
EXTENDING WELL UPSTREAM INTO EASTERN PORTION OF PACIFIC OCEAN.
FARTHER UPSTREAM TROUGHING IS PRESENT NORTH OF HAWAII. THAT TROUGH
IS ESSENTIALLY EXTENSION OF TROUGHING RESIDING OVER NORTHERN
PORTIONS OF CANADA ON NORTHERN PORTION OF WESTERN CONUS RIDGE. OVER
TIME...TROUGH OVER GREAT LAKES SYNCS UP WITH TROUGHING OVER NORTHERN
CANADA RESULTING IN FAST AND ACTIVE WEST-NORTHWEST FLOW ACROSS
MOST OF THE CONUS THROUGH THE UPCOMING WEEKEND.
TWO SHORTWAVES PROGGED TO DROP THROUGH IN THIS FLOW PATTERN INTO
THIS WEEKEND. FIRST WAVE ALONG WITH WEAK SFC-H85 LOW-LEVEL WARM AIR
ADVECTION GLANCES UPR LAKES TO WEST ON THURSDAY. WAVE IS DIGGING
INTO THE MEAN TROUGH WHICH FAVORS MORE OF A SOUTH AND/OR WEST TRACK
AND IS PRETTY PROGRESSIVE. ALSO LOOKS LIKE ANY UPPER JET SUPPORT
REMAINS WEST OF UPR MICHIGAN. MODELS VARY WILDLY FROM SOUTH TO NORTH
WHERE THE MOST QPF/SNOW IS EXPECTED. GEM-NH ON SOUTHERN EXTREME...
TRACKING ACROSS IOWA...WHILE NAM IS OVER WESTERN UPR MICHIGAN. NAM
IS ON NORTH EDGE OF EVEN SREF...SO IT IS CERTAINLY AN OUTLIER. GFS
AND ECMWF IN BTWN...BUT ARE STILL MAINLY OVER WISCONSIN. SINCE THERE
IS A SLIGHT EASTWARD TREND IN MODELS...WILL BRING CHANCE POPS OVER
WESTERN CWA ON THURSDAY. OTHER ISSUE...PREVIOUSLY MENTIONED BY MID
SHIFT...IS POSSIBLE FREEZING DRIZZLE LATER THURSDAY INTO THURSDAY
NIGHT. BASED ON FORECAST SOUNDINGS...WI BORDER/SCNTRL...WILL HAVE
BEST CHANCE SEEING THIS ONCE ANY SNOW DECREASES. ELSEWHERE...THINK
TOO MUCH DRIER AIR IS AROUND BLO H85 TO HAVE IN THERE. SINCE AM NOT
CERTAIN WHERE ULTIMATELY THE STEADIER SNOW SETS UP OVR CWA...IF IT
DOES AT ALL...WILL KEEP FZDZ OUT OF FCST.
COUPLE OF SUBTLE THINGS HAPPEN LATER THURSDAY INTO THURSDAY NIGHT
THAT MAY HAVE LARGE IMPACT ON FORECAST FOR FRIDAY. ALL MODELS INDICATE
STRONGER NORTHERN STREAM WAVE TRACKS WELL TO THE NORTH OVER NORTHWEST
ONTARIO THURSDAY NIGHT. WE ARE GOOD THERE. TROUBLE IS THAT SAME
MODELS DIFFER ON HOW FAR SOUTH TO BRING LOW-LEVEL COLD AIR IN WAKE OF
SHORTWAVE BY FRIDAY MORNING. GEM-NH FARTHER SOUTH WITH COLD AIR AND
TRENDS FROM GFS ALSO INDICATE FARTHER SOUTH LOW-LEVEL TEMPERATURE
GRADIENT AT SFC-H85. ECMWF NOT AS COLD THOUGH. LOCATION OF TIGHTER
LOW-LEVEL TEMPERATURE GRADIENT COULD PAVE THE WAY FOR WHERE HEAVIER
QPF/SNOW SETS UP ON FRIDAY AS SHORTWAVE AND SFC-H85 LOWS MOVE IN FROM
NORTHERN PLAINS.
THIS SECOND SHORTWAVE IS MUCH STRONGER THAN ONE MOVING THROUGH 24 HR
EARLIER AND HAS POTENTIAL TO BRING WIDESRPEAD SNOW TO UPPER LAKES ON
FRIDAY. WHERE EVER LOW-LEVEL BAROCLINIC ZONE SETS UP THERE ARE
ENHANCING FACTORS THAT MAY RESULT IN SWATH OF MODERATE TO HEAVY SNOW
INCLUDING DIVERGENCE ALOFT FROM RIGHT ENTRANCE REGION OF JET STREAK
DROPPING INTO GREAT LAKES FROM ONTARIO...DECENT MOISTURE ADVECTION
WITH H7 MIXING RATIOS OVR 3G/KG...AND OVERALL STRENGTHENING SFC-H85
LOWS/LOW-LEVEL FLOW. ADVY LEVEL SNOWS CERTAINLY POSSIBLE. INCREASED
POPS TO LIKELY OVER WEST AND SOUTH...WHERE MODEL AGREEMENT IS HIGHER
THAT SNOW OCCURS. WWD DAY 3 GRAPHICS INDICATE UP TO 4 INCHES OVER
WEST THIRD OF CWA ON FRIDAY. IF FARTHER NORTH ECMWF AND GEM-NH ARE
CORRECT...THEN LIKELY POPS WILL BE NEEDED FOR MOST AREAS ON FRIDAY.
AT FIRST GLANCE A MAINLY QUIET WEEKEND AS HIGH PRESSURE IS MAIN
FEATURE OVER REGION. COULD BE RE-INFORCING SHOT OF COLDER AIR AND
SOME DEEPER MOISTURE COME IN LATER SATURDAY AND SATURDAY NIGHT.
GFS/ECMWF INDICATE INCREASE IN POPS DURING THAT TIME. KEPT CHANCY
POPS IN ALONG LK SUPERIOR WITH ADDED POTENTIAL FOR LK EFFECT AS H85
TEMPS DROP INTO THE -15C TO -20C RANGE. RECORD SETTING WARMTH OF MID
MARCH IN 2012 WILL BE BUT A DISTANT MEMORY COMPARED TO THE CHILL OF
THIS YEAR.
COOL AND ACTIVE PATTERN CONTINUES INTO EARLY NEXT WEEK...AND
PROBABLY EVEN INTO LATER MARCH AS WELL. CERTAINLY NOT DONE WITH
WINTER YET. DEEPER SHORTWAVE TROUGH EMERGES FROM TROUGHING OVER
NORTHERN CANADA AND EVENTUALLY TRACKS ACROSS ROCKIES LATE IN THE
WEEKEND. THIS TROUGH THEN DEEPENS ACROSS THE MIDDLE CONUS MONDAY AND
MOVES INTO THE GREAT LAKES ON TUESDAY. DEEPENING LOW PRESSURE SYSTEM
RESULTS WHICH DRAWS UP GULF MOISTURE AND COULD LEAD TO SIGNIFICANT
SNOW SOMEWHERE UPPER MIDWEST THROUGH THE GREAT LAKES...INCLUDING UPR
MICHIGAN. OVERALL THE ECMWF IS DEEPER AND FARTHER NORTH WITH SFC
LOW...THOUGH LATEST RUN BACKED OFF WITH STRENGTH OF LOW. GFS IS MORE
SUPPRESSED WITH TRACK OF SFC LOW. WPC...FORMALLY HPC...HAND DRAWN
PROGS BTWN THE TWO WITH LOW MOVING ACROSS LOWER LAKES AND UPR
MICHIGAN JUST ON THE FRINGE. CONSENSUS POPS ARE IN THE CHANCE RANGE
WHICH IS FINE AT THIS POINT. GIVEN NORTHEAST WINDS AND COOLER
AIR...INCREASED POPS CLOSER TO LK SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 121 PM EDT TUE MAR 12 2013
EXPECT PREVAILING IFR/MVFR CONDITIONS TO GIVE WAY TO A PERIOD OF
LIFR CONDITIONS AT ALL 3 SITES LATE THIS AFTN/EVNG AS A LO PRES
TROF/AREA OF DEEPER MSTR CROSSES UPR MI AND BRINGS AT LEAST SEVERAL
HRS OF LK ENHANCED SHSN. SUBSIDENCE/DRYING IN THE WAKE OF THE TROF
PASSAGE WL RESULT IN CONDITIONS IMPROVING TO HI END MVFR OR EVEN VFR
LATE TNGT/WED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE MAR 12 2013
UNDER THE TIGHTENING PRES GRADIENT IN THE WAKE OF A TROF PASSAGE
THIS EVENING...EXPECT A N GALE UP TO 35 KTS OVER PORTIONS OF
NCENTRAL LAKE SUP MUCH OF TONIGHT. FREEZING SPRAY WILL BE
WIDESPREAD. AS THE GRADIENT WEAKENS LATE TONIGHT THRU WED...THE
WINDS WILL GRADUALLY DIMINISH AND BACK TOWARD THE NW WITH APPROACH
OF HI PRES FROM THE W. WINDS OF LESS THAN 20 KTS PERSIST INTO
THURSDAY AS HIGH PRESSURE SLIDES ACROSS. SOUTHWESTERLY RETURN FLOW
ON BACK SIDE OF HIGH MAY GET GUSTY OVER 25 KTS BY THU NIGHT. COLD
FRONT SHIFTS THROUGH OVERNIGHT THURSDAY NIGHT WITH NORTHWEST WINDS
TRYING TO REACH 30 KTS. NORTHERLY WINDS TO 25 KTS CONTINUE INTO FRI.
WINDS DIMINISH THROUGH REST OF WEEKEND AS HIGH PRESSURE RETURNS. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR MIZ006-007-
085.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR MIZ001-
003>005-084.
LAKE EFFECT SNOW WARNING UNTIL 2 AM EDT /1 AM CDT/ WEDNESDAY FOR
MIZ002-009.
LAKE SUPERIOR...
GALE WARNING FROM 8 PM THIS EVENING TO 5 AM EDT WEDNESDAY FOR
LSZ243-244-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
120 AM EDT TUE MAR 12 2013
.UPDATE...
ISSUED AT 636 PM EDT MON MAR 11 2013
PER WATER VAPOR IMAGERY...SHORTWAVE LIFTING N THRU WRN LWR MI IS
LOOKING INCREASINGLY IMPRESSIVE...AND IR IMAGERY SHOWS RAPIDLY
COOLING CLOUD TOPS THRU NRN LWR MI AS DEEP LAYER FORCING
STRENGTHENS. AS A RESULT...RADAR IMAGERY SHOWS EXPANDING PCPN ACROSS
NRN LWR MI. HAVE INCREASED POPS TO CATEGORICAL OVER THE FAR ERN FCST
AREA FOR SEVERAL HRS THIS EVENING AS EXPANDING/INTENSIFYING PCPN
SHIELD LIFTS N. COLUMN SHOULD RAPIDLY COOL...GIVING A QUICK
TRANSITION FROM MOSTLY LIQUID TO SNOW AS PCPN ARRIVES. INCLUDED 1-2
INCH SNOW AMOUNTS ACROSS LUCE COUNTY...BUT WILL NEED TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HRS AS IT`S NOT OUT OF THE QUESTION
THAT THIS COULD TURN INTO AN ADVY TYPE SNOW EVENT OVER THE FAR E
GIVEN THE STRENGTHENING SHORTWAVE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF OVER
CENTRAL AND ERN NAMERICA. NEGATIVELY TILTED CLOSED LO OVER THE LOWER
GRT LKS IS TENDING TO LIFT TO THE NE AS ANOTHER SHRTWV DROPPING THRU
SCENTRAL CANADA DIGS INTO THE NRN PLAINS. THE SFC LO ASSOCIATED WITH
THIS DISTURBANCE HAS PUSHED TO NEAR MANISTIQUE AS OF MID AFTN. SFC
TEMPS AT ISQ/ERY HAVE RISEN INTO THE MID/UPR 30S TO THE E OF THE SFC
LO...AND THERE IS SOME FOG HERE WITH THE DRY AIR MOVING OVER
LINGERING LLVL MSTR. THE ARRIVAL OF THE DRY SLOT ASSOCIATED WITH THE
UPR LO HAS ENDED MOST OF THE PCPN EXCEPT OVER THE WRN COUNTIES...
WHICH LIE UNDER THE DEFORMATION ZN ON THE CYC SIDE OF THE H7 LO
TRACK. PERIODS OF SN HAVE BEEN MOST PERSISTENT IN THESE AREAS
TDAY...WITH SN FALL RATES UP TO 0.5-0.75 INCH/HR. ALTHOUGH THE DRY
SLOT HAS SWEPT THRU THE CNTRL COUNTIES...SOME -SN CONTINUES OVER
MAINLY NCENTRAL MQT COUNTY WITH CYC UPSLOPE N WIND PROVIDING
SUFFICIENT LIFT. ANOTHER AREA OF -SHRASN ASSOCIATED WITH THE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THE UPR LO IS APRCHG THE SE
COUNTIES...BUT PRESENCE OF LARGER SCALE DRY SLOT LOOKS TO BE
LIMITING THE COVERAGE TO SCT -SHRASN. TO THE W...12Z YPL/INL RAOBS
SHOW A DRIER/MORE STABLE AIRMASS IS PRESENT OVHD TO THE W OF THE
DEFORMATION ZN IN MN...AND THERE IS LTL PCPN FALLING THERE. ALTHOUGH
A FAIRLY IMPRESSIVE COMMA CLD APPEARS ASSOCIATED WITH THE SHRTWV
DIGGING INTO THE NRN PLAINS...PCPN APPEARS TO BE CONFINED TO AN AREA
NEAR LK WINNIPEG RIGHT UNDER THE COMMA HEAD.
MAIN FCST CONCERNS TNGT ARE SN TRENDS/GOING HEADLINES. FOCUS FOR TUE
SHIFTS TO POTENTIAL IMPACT OF SHRTWV DIGGING INTO THE NRN PLAINS.
TNGT...MODELS SHOW SFC LO LIFTING NEWD INTO SE ONTARIO TNGT...BUT
CLOSED LO/DEEPER MSTR TENDING TO LINGER OVER THE UPR LKS DESPITE
ARRIVAL OF DEEP LYR QVECTOR DVGC BY 06Z. AREA OF -SHRASN LIFTING NWD
THRU LK MI AHEAD OF THE UPR LO WL IMPACT THE ERN ZNS THIS EVNG WITH
AREAS OF FOG LINGERING THERE UNTIL SFC LO PASSES TO THE NE THIS EVNG
AND COLDER AIR ARRIVES. SUSPECT LINGERING DEFORMATION ZN PCPN OVER
THE WRN CWA WL SLOWLY DIMINISH WITH ARRIVAL OF THE NEGATIVE
FORCING...SO ENDED THE GOING HEADLINES AS SCHEDULED 00Z TO 06Z FM SW
TO NE. DOWNGRADED THE WARNINGS FOR BARAGA/MQT COUNTIES VALID THRU 0Z
WITH BULK OF PCPN EXPECTED TO FALL FARTHER W ON CYC SIDE OF H7 LO
TRACK. EVEN THOUGH THE STEADY SN WL TEND TO DIMINISH OVER THE
W...CYC NW FLOW OF AIR/ARRIVAL OF COLDER AIR WITH H85 TEMPS PROGGED
TO SINK AS LO AS -14C TO -15C BY 12Z TUE WL CAUSE NMRS SHSN TO
PERSIST. BUT CONCERNED LO INVRN HGTS/DRY MID LVL AIR SHOWN ON THE
12Z INL/YPL RAOBS WL LIMIT THE COVERAGE/INTENSITY OF THE SHSN...SO
WENT NO HIER THAN LIKELY POPS FOR NOW.
TUE...DISTURBANCE MOVING THRU THE NRN PLAINS/ACCOMPANYING DEEP LYR
QVECTOR CNVGC IS PROGGED TO MOVE TOWARD THE CWA...SO MAINTAINED
GOING INCRSG POPS TO CATEGOCIAL NEAR LK SUP BY LATE AFTN WITH FAIRLY
SHARP CYC NW FLOW ACTING AS AN ENHANCEMENT FACTOR IN THE PRESENCE OF
DEEPER MSTR/H85 TEMPS NOT FAR FM -15C. SINCE FCST SDNGS SHOW THE DGZ
SEVERAL THOUSAND FEET DEEP IN THE CONVECTIVE LYR...CONCERNED SOME
ADVY INTENSITY LES MIGHT OCCUR LATER IN THE DAY...ESPECIALLY IN THE
UPSLOPE AREAS OVER THE W.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
WITH AN UPPER LOW JUST E OF THE CWA AT 00Z WED AND A SFC TROUGH OVER
LAKE SUPERIOR...850MB TEMPS WILL BE AROUND -14 WITH CYCLONIC NW-NNW
LOW LEVEL WINDS. THESE CONDITIONS WILL BE FAVORABLE FOR LES TUE
NIGHT...WITH WARMING TEMPS VERY DRY LOW LEVEL AIR MOVING IN WITH A
SFC RIDGE LATE TUE NIGHT INTO WED NIGHT. EXPECT A RELATIVELY QUICK
BURST OF MODERATE LES ALONG AND JUST BEHIND THE SFC TROUGH THAT MAY
BRING A QUICK 2-4 INCHES OF SNOW OVER THE FAVORED HIGHER TERRAIN.
WITH THE RATE THAT THE VERY DRY AIR MOVES IN LATE TUE NIGHT...LES
WILL QUICKLY WEAKEN...AND SHOULD BE ALMOST COMPLETELY GONE BY 15Z
WED /IF NOT A BIT EARLIER/. MODELS THEN INDICATE AN AREA OF
INCREASED LOW LEVEL MOISTURE AND INCREASED LAKE INDUCED EQUILIBRIUM
LEVELS MOVING ACROSS CENTRAL LAKE SUPERIOR ALONG A WEAK SFC TROUGH
WED NIGHT. WILL KEEP SLIGHT CHANCE POPS E OF MARQUETTE AS CONDITIONS
WILL STILL ONLY BE MARGINAL FOR LES. ELSEWHERE WED NIGHT...CLEARING
OVER THE INTERIOR W SHOULD ALLOW MIN TEMPS TO FALL TO NEAR ZERO.
A COUPLE OF SHORTWAVES LOOK TO MOVE NEARBY THU/THU NIGHT...BUT
CONSENSUS OF MODELS PLACES BEST FORCING AND PRECIP N AND S OF THE
CWA...SO WILL KEEP ANY POPS ON THE LOW SIDE.
ANOTHER SHORTWAVE...BACKED UP BY THE LEFT EXIT REGION OF A 120+KT
JET...MOVES THROUGH FRI INTO FRI NIGHT. MODEL VARY WITH TIMING...BUT
GENERALLY AGREE ON OVERALL EXTENT/STRENGTH OF THE SYSTEM. MODELS
PAINT A QUARTER TO A THIRD OF AN INCH OF QPF...AND THE BEST OMEGA
LOOKS TO BE JUST BELOW AND INTO THE DGZ...WHICH SHOULD KEEP SNOW TO
LIQUID RATIOS FROM GETTING TOO LOW. STILL DIFFICULT TO SAY GIVEN
VOLATILE NATURE OF SHORTWAVES THAT FAR OUT...BUT COULD SEE A FEW
INCHES OF SNOW ACROSS THE AREA. 850MB TEMPS AOB -14C AND N-NW FLOW
BEHIND THE SYSTEM WOULD BRING SOME ADDITIONAL LES INTO SAT /AND
POSSIBLY BEYOND BUT TOO UNCERTAIN IN ANY DETAILS THAT FAR OUT TO
MENTION OR ADD TO THE FORECAST/.
HIGHS TEMPS WILL BE IN THE 20S ON WED...WITH A WARM UP TO AROUND 30
ON THU AND INTO THE MID 30S ON FRI. TEMPS LOOK TO DECREASE GOING
INTO THE WEEKEND AND EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 119 AM EDT TUE MAR 12 2013
WITH ABUNDANT MOISTURE AND CYCLONIC FLOW...MVFR/IFR CONDITIONS WILL
CONTINUE THRU THIS FCST PERIOD. AT KIWD AND KCMX...EXPECT PREVAILING
MVFR CONDITIONS TO FALL TO IFR OVERNIGHT AS COOLING AIRMASS/CYCLONIC
FLOW AID -SHSN OFF THE LAKE. AT KSAW...MVFR CONDITIONS WILL LIKELY
PERSIST OVERNIGHT AS NW FLOW WILL NOT BE AS FAVORABLE FOR DEVELOPING
LAKE EFFECT -SHSN. NEXT DISTURBANCE DROPPING INTO THE GREAT LAKES
TODAY WILL BRING AN INCREASE IN COVERAGE/INTENSITY OF SHSN LATE
MORNING THRU THE AFTN. IFR CONDITIONS SHOULD GENERALLY PREVAIL AT
ALL 3 SITES IN THE AFTN WITH THE POTENTIAL FOR BRIEF LIFR AT TIMES
AT KIWD/KCMX. EXPECT SOME PERIODS OF MVFR AS WELL. IMPROVEMENT WILL
GET UNDERWAY TONIGHT AS MID LEVEL TROF DEPARTS...ALLOWING RATHER
SIGNIFICANT DRYING TO SPREAD INTO THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT MON MAR 11 2013
EXPECT SLOWLY DIMINISHING NNE WINDS TO BACK TO THE NW TNGT INTO TUE
AS SFC LO OVER ERN UPR MI THIS EVNG MOVES NEWD THRU ONTARIO TOWARD
JAMES BAY. EVEN THOUGH WINDS WL BE SLOWLY DIMINISHING...THE ARRIVAL
OF COLDER AIR WL RESULT IN SOME FREEZING SPRAY.
A TROUGH WILL MOVE THROUGH LATE TUESDAY AND TUESDAY NIGHT...CAUSING
WINDS TO GUST NEAR 35KTS OVER CENTRAL AND EASTERN LAKE SUPERIOR.
WINDS RELAX WEDNESDAY AND WEDNESDAY NIGHT AS A RIDGE MOVES THROUGH.
BEHIND THE RIDGE. WINDS WILL REMAIN BELOW 20KTS THROUGH THE REST OF
THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC/TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
912 PM CDT WED MAR 13 2013
.UPDATE...
UPDATED THE GRIDS FOR LATER TONIGHT TO ACCOUNT FOR A NARROWER
BAND OF SNOW THAN WAS ANTICIPATED EARLIER. THE HI RES MODELS AND
MESOSCALE MODELS OF HOPWRF...NAM...AND RAP ALL INDICATE A NARROW
BAND OF MODERATE SNOW SLIDING SOUTHEAST ACROSS CENTRAL MN...
INTO...OR JUST EAST OF THE TWIN CITIES METRO...AND ALONG THE
MISSISSIPPI RIVER OF SERN MN BY THURSDAY MORNING. 21Z RUN OF THE
HOPWRF IS SHIFTING THIS POTENTIAL A ROW OF COUNTIES FURTHER EAST.
WILL SEE A QUICK 1 TO 3 INCHES WITHIN 4 OR 5 HOURS WITH THIS BAND.
BEST TIMING WOULD BE BETWEEN MIDNIGHT AND 4 AM ACROSS CENTRAL
MN...3 TO 7 AM FOR THE TWIN CITIES METRO AND WRN WI...AND 5 TO 9
AM ACROSS SERN MN.
THINK THE POTENTIAL IS LOW ENOUGH ACROSS SWRN MN TO REMOVE MENTION
OF POP ALTOGETHER...ALTHOUGH A FEW FLURRIES ARE THEORETICALLY
POSSIBLE.
GRIDS ARE PUBLISHED AND TEXT PRODUCTS HAVE BEEN ISSUED.
BORGHOFF
&&
.PREV DISCUSSION...
/ISSUED 350 PM CDT WED MAR 13 2013/
SEVERAL CONCERNS ONCE AGAIN THIS FORECAST PERIOD. A COUPLE OF
CLIPPER TYPE SYSTEMS WITH SOME P-TYPE ISSUES ASSOCIATED WITH THEM
AND THEN THE LONGER TERM TRENDS OF THE MORE SIGNIFICANT STORM
POSSIBLE LATER SUNDAY NIGHT INTO MONDAY NIGHT.
FIRST SHORT WAVE TROUGH TO MOVE INTO THE AREA LATE THIS EVENING
AND SPREAD RAPIDLY SOUTHEAST THROUGH 12Z. THICKNESS PROGS DO
INDICATE POSSIBLE LIGHT FREEZING RAIN THREAT INTO SOUTHWEST
MINNESOTA DURING THE LATE NIGHT/EARLY MORNING. WILL HAVE TO
MONITOR THIS THREAT THIS EVENING TO SEE IF THIS WILL BE WIDESPREAD
OR NOT. OTHERWISE IT REMAINS COLD ENOUGH FOR SNOW IN THE NORTHEAST
TWO THIRDS OF THE CWA OVERNIGHT. TIMING IS RATHER POOR FOR EAST
CENTRAL MN AS IT APPEARS THE BEST SHOT OF SNOW WILL BE AROUND THE
RUSH HOUR THURSDAY MORNING. AT THE MOMENT WE HAVE 1 TO 2 INCH
ACCUMULATIONS IN THIS QUADRANT THROUGH THE DAY THURSDAY.
BRIEF RESPITE IN THE PRECIPITATION THREAT EARLY THURSDAY NIGHT
BEFORE THE NEXT SHORT WAVE DROPS SOUTHEAST OVER THE AREA FOR FRIDAY.
FOLLOWED MORE OF A GFS SOLUTION DURING THE PERIOD...WHICH WOULD
FAVOR MAINLY SNOW OVER THE NORTHERN CWA. COULD BE A MIX OF
FREEZING RAIN/RAIN MORNING/EARLY AFTERNOON...BUT MUCH OF THIS
SHOULD FALL AS SNOW. FARTHER SOUTH...MIXED FREEZING RAIN AND SNOW
POSSIBLE IN THE SOUTHERN CWA...AND MAY CHANGE OVER TO JUST RAIN IN
THE AFTERNOON...AS THICKNESS VALUES REMAIN HIGH OVER THE FAR
SOUTH. STILL APPEARS WHATEVER REMAINS WILL CHANGE BACK OVER TO
LIGHT SNOW LATE IN THE AFTERNOON. FORECAST SNOW ACCUMULATION DOES
JUMP INTO THE ADVISORY REALM WITH 2 TO 5 INCHES MAINLY NORTH OF
MORRIS...GLENCOE AND RED WING LINE. WILL HAVE TO MONITOR SOUTHERN
AREAS EARLY FOR POSSIBLE MIXED PRECIPITATION HAZARDS.
COOL TEMPERATURES REMAIN INTO NEXT WEEK. LONG TERM MODELS CONTINUE
TO SHOW STRONG STORM MOVING INTO THE REGION LATER SUNDAY AND
LASTING THROUGH MONDAY. BOTH THE 12Z ECMWF AND GFS SHOW HEAVY
ACCUMULATIONS AND STRONG WINDS IN THE STORMS WAKE. THE 12Z ECMWF
OCCLUDES THE STORM EARLY MONDAY BUT REMAINS COLD ENOUGH FOR JUST
SNOW DURING THE PERIOD. THE GFS HINTS AT A POSSIBLE MIX
EARLY...BUT THE STRONG HEIGHT FALLS/DYNAMICS ASSOCIATED WITH THE
LOW SHOULD BE STRONG ENOUGH TO CHANGE ANY MIX IN THE SOUTH TO SNOW
FAIRLY RAPIDLY. THE LATEST TREND ON THE FIM MODEL ALSO INDICATES
THE DEEP LOW TRAVERSING EXTREME SOUTHERN MN AS WELL. SIGNIFICANT
IMPACTS WILL LIKELY OCCUR WITH THIS SYSTEM IF CURRENT TRENDS
CONTINUE.
&&
.AVIATION.../00Z TAF ISSUANCE/
CHANGES MADE IN THE TAF PACKAGE INCLUDED SPEEDING UP ARRIVAL OF
POTENTIAL SNOW TONIGHT...REMOVING SN MENTION FROM AXN...AND
IMPROVING CLOUD HEIGHTS CONSIDERABLY. IMPROVEMENTS BASED ON
CURRENT OBS IN NODAK AND SRN CANADA...WHICH SHOW NOT MUCH SNOW IS
FALLING OR MVFR CIGS MATERIALIZING...CONTRARY TO WHAT MUCH OF THE
EARLIER GUIDANCE SUGGESTED. BASED SNOWFALL IN TAFS ON A BLEND OF THE
18Z NAM AND RAP...WHICH BOTH SHOW NOT MUCH MORE THAN A 30 MILE WIDE
BAND OF SNOW WORKING SE FROM NW MN ACROSS ERN MN AND WRN WI.
THOUGH NARROW...THIS WILL BE A POTENT AND QUICK HITTING BURST OF
SNOW...WITH A QUICK 1-2 INCHES OF SNOW EXPECTED WITHIN ABOUT A 3
HOUR WINDOW. BEHIND THIS SYSTEM...NAM/GFS SOUNDINGS SHOW LOTS OF
LOW LEVEL MOISTURE HANGING OUT ACROSS THE AREA AHEAD OF A COLD
FRONT THAT ARRIVES IN CENTRAL MN THU EVENING. THIS INDICATES THE
POTENTIAL FOR LOTS OF IFR OR LOWER STRATUS AND MVFR OR LOWER
BR...BUT LIKE THE SNOW...LACK OF OBS TO THE WEST PUSHED THESE TAFS
TOWARD THE OPTIMISTIC VFR END OF THINGS. LOOKING AT NAM/GFS
925-850 RH...REALLY NOT SEEING A STRONG SIGNAL FOR THE RETURN OF
LOW STRATUS UNTIL FRI MORNING.
KMSP...STILL QUESTIONABLE IF MSP SEES SNOW...WITH THE 22 AND 23Z
RUNS OF THE RAP KEEPING THE NARROW BAND OF SNOW EAST OF THE FIELD.
BASED ON NAM/HOPWRF ENSEMBLE MEMBERS...BEST TIMING FOR SNOW LOOKS
TO BE A VERY NARROW WINDOW BETWEEN 9Z AND 11Z...WITH ALL PRECIP
OUT OF THE AREA BY 13Z. THIS IS GOOD...SINCE IF PRECIP LASTED MUCH
LONGER...THEN WOULD HAVE TO WORRY ABOUT P-TYPE. WIND DIRECTION
FORECAST ALSO LOOKS TO GET TRICKY BY THURSDAY AFTERNOON...AS
GRADIENT GETS BAGGY OUT AHEAD OF THE COLD FRONT FOR THU NIGHT.
FOLLOWED TREND OF GUIDANCE...WHICH IS TO TAKE LIGHT WINDS
GRADUALLY OVER TO THE WNW. OTHER AREA OF CONCERN IS THAT BOTH THE
NAM/GFS WOULD SAY MSP ENDS UP IN IFR OR LOWER STRATUS BEHIND THE
MORNING WAVE. AT THIS POINT...NOTHING LIKE THIS IS BEING OBSERVED
NORTHWEST OF HERE SO WENT OPTIMISTIC WITH THIS TAF...BUT IF IT
DOES START TO APPEAR LATER TONIGHT...THEN MSP COULD SPEND MUCH OF
THURSDAY WITH IFR CIGS AND MVFR VIS.
/OUTLOOK FOR KMSP/
FRI...IFR/MVFR CIGS. CHC OF SN/FZRA/RA. WINDS N/NE 5-10 KTS.
SAT...MVFR/VFR CIGS. WINDS NW 5-10 KTS.
SUN...VFR EARLY...WITH MVFR/IFR CIGS/VSBYS IN SN LATE. WINDS E
5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
721 PM CDT WED MAR 13 2013
.UPDATE...
00Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 350 PM CDT WED MAR 13 2013/
SEVERAL CONCERNS ONCE AGAIN THIS FORECAST PERIOD. A COUPLE OF
CLIPPER TYPE SYSTEMS WITH SOME P-TYPE ISSUES ASSOCIATED WITH THEM
AND THEN THE LONGER TERM TRENDS OF THE MORE SIGNIFICANT STORM
POSSIBLE LATER SUNDAY NIGHT INTO MONDAY NIGHT.
FIRST SHORT WAVE TROUGH TO MOVE INTO THE AREA LATE THIS EVENING
AND SPREAD RAPIDLY SOUTHEAST THROUGH 12Z. THICKNESS PROGS DO
INDICATE POSSIBLE LIGHT FREEZING RAIN THREAT INTO SOUTHWEST
MINNESOTA DURING THE LATE NIGHT/EARLY MORNING. WILL HAVE TO
MONITOR THIS THREAT THIS EVENING TO SEE IF THIS WILL BE WIDESPREAD
OR NOT. OTHERWISE IT REMAINS COLD ENOUGH FOR SNOW IN THE NORTHEAST
TWO THIRDS OF THE CWA OVERNIGHT. TIMING IS RATHER POOR FOR EAST
CENTRAL MN AS IT APPEARS THE BEST SHOT OF SNOW WILL BE AROUND THE
RUSH HOUR THURSDAY MORNING. AT THE MOMENT WE HAVE 1 TO 2 INCH
ACCUMULATIONS IN THIS QUADRANT THROUGH THE DAY THURSDAY.
BRIEF RESPITE IN THE PRECIPITATION THREAT EARLY THURSDAY NIGHT
BEFORE THE NEXT SHORT WAVE DROPS SOUTHEAST OVER THE AREA FOR FRIDAY.
FOLLOWED MORE OF A GFS SOLUTION DURING THE PERIOD...WHICH WOULD
FAVOR MAINLY SNOW OVER THE NORTHERN CWA. COULD BE A MIX OF
FREEZING RAIN/RAIN MORNING/EARLY AFTERNOON...BUT MUCH OF THIS
SHOULD FALL AS SNOW. FARTHER SOUTH...MIXED FREEZING RAIN AND SNOW
POSSIBLE IN THE SOUTHERN CWA...AND MAY CHANGE OVER TO JUST RAIN IN
THE AFTERNOON...AS THICKNESS VALUES REMAIN HIGH OVER THE FAR
SOUTH. STILL APPEARS WHATEVER REMAINS WILL CHANGE BACK OVER TO
LIGHT SNOW LATE IN THE AFTERNOON. FORECAST SNOW ACCUMULATION DOES
JUMP INTO THE ADVISORY REALM WITH 2 TO 5 INCHES MAINLY NORTH OF
MORRIS...GLENCOE AND RED WING LINE. WILL HAVE TO MONITOR SOUTHERN
AREAS EARLY FOR POSSIBLE MIXED PRECIPITATION HAZARDS.
COOL TEMPERATURES REMAIN INTO NEXT WEEK. LONG TERM MODELS CONTINUE
TO SHOW STRONG STORM MOVING INTO THE REGION LATER SUNDAY AND
LASTING THROUGH MONDAY. BOTH THE 12Z ECMWF AND GFS SHOW HEAVY
ACCUMULATIONS AND STRONG WINDS IN THE STORMS WAKE. THE 12Z ECMWF
OCCLUDES THE STORM EARLY MONDAY BUT REMAINS COLD ENOUGH FOR JUST
SNOW DURING THE PERIOD. THE GFS HINTS AT A POSSIBLE MIX
EARLY...BUT THE STRONG HEIGHT FALLS/DYNAMICS ASSOCIATED WITH THE
LOW SHOULD BE STRONG ENOUGH TO CHANGE ANY MIX IN THE SOUTH TO SNOW
FAIRLY RAPIDLY. THE LATEST TREND ON THE FIM MODEL ALSO INDICATES
THE DEEP LOW TRAVERSING EXTREME SOUTHERN MN AS WELL. SIGNIFICANT
IMPACTS WILL LIKELY OCCUR WITH THIS SYSTEM IF CURRENT TRENDS
CONTINUE.
&&
.AVIATION.../00Z TAF ISSUANCE/
CHANGES MADE IN THE TAF PACKAGE INCLUDED SPEEDING UP ARRIVAL OF
POTENTIAL SNOW TONIGHT...REMOVING SN MENTION FROM AXN...AND
IMPROVING CLOUD HEIGHTS CONSIDERABLY. IMPROVEMENTS BASED ON
CURRENT OBS IN NODAK AND SRN CANADA...WHICH SHOW NOT MUCH SNOW IS
FALLING OR MVFR CIGS MATERIALIZING...CONTRARY TO WHAT MUCH OF THE
EARLIER GUIDANCE SUGGESTED. BASED SNOWFALL IN TAFS ON A BLEND OF THE
18Z NAM AND RAP...WHICH BOTH SHOW NOT MUCH MORE THAN A 30 MILE WIDE
BAND OF SNOW WORKING SE FROM NW MN ACROSS ERN MN AND WRN WI.
THOUGH NARROW...THIS WILL BE A POTENT AND QUICK HITTING BURST OF
SNOW...WITH A QUICK 1-2 INCHES OF SNOW EXPECTED WITHIN ABOUT A 3
HOUR WINDOW. BEHIND THIS SYSTEM...NAM/GFS SOUNDINGS SHOW LOTS OF
LOW LEVEL MOISTURE HANGING OUT ACROSS THE AREA AHEAD OF A COLD
FRONT THAT ARRIVES IN CENTRAL MN THU EVENING. THIS INDICATES THE
POTENTIAL FOR LOTS OF IFR OR LOWER STRATUS AND MVFR OR LOWER
BR...BUT LIKE THE SNOW...LACK OF OBS TO THE WEST PUSHED THESE TAFS
TOWARD THE OPTIMISTIC VFR END OF THINGS. LOOKING AT NAM/GFS
925-850 RH...REALLY NOT SEEING A STRONG SIGNAL FOR THE RETURN OF
LOW STRATUS UNTIL FRI MORNING.
KMSP...STILL QUESTIONABLE IF MSP SEES SNOW...WITH THE 22 AND 23Z
RUNS OF THE RAP KEEPING THE NARROW BAND OF SNOW EAST OF THE FIELD.
BASED ON NAM/HOPWRF ENSEMBLE MEMBERS...BEST TIMING FOR SNOW LOOKS
TO BE A VERY NARROW WINDOW BETWEEN 9Z AND 11Z...WITH ALL PRECIP
OUT OF THE AREA BY 13Z. THIS IS GOOD...SINCE IF PRECIP LASTED MUCH
LONGER...THEN WOULD HAVE TO WORRY ABOUT P-TYPE. WIND DIRECTION
FORECAST ALSO LOOKS TO GET TRICKY BY THURSDAY AFTERNOON...AS
GRADIENT GETS BAGGY OUT AHEAD OF THE COLD FRONT FOR THU NIGHT.
FOLLOWED TREND OF GUIDANCE...WHICH IS TO TAKE LIGHT WINDS
GRADUALLY OVER TO THE WNW. OTHER AREA OF CONCERN IS THAT BOTH THE
NAM/GFS WOULD SAY MSP ENDS UP IN IFR OR LOWER STRATUS BEHIND THE
MORNING WAVE. AT THIS POINT...NOTHING LIKE THIS IS BEING OBSERVED
NORTHWEST OF HERE SO WENT OPTIMISTIC WITH THIS TAF...BUT IF IT
DOES START TO APPEAR LATER TONIGHT...THEN MSP COULD SPEND MUCH OF
THURSDAY WITH IFR CIGS AND MVFR VIS.
/OUTLOOK FOR KMSP/
FRI...IFR/MVFR CIGS. CHC OF SN/FZRA/RA. WINDS N/NE 5-10 KTS.
SAT...MVFR/VFR CIGS. WINDS NW 5-10 KTS.
SUN...VFR EARLY...WITH MVFR/IFR CIGS/VSBYS IN SN LATE. WINDS E
5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
101 AM CDT TUE MAR 12 2013
.AVIATION...06Z TAFS.
MVFR CIGS WITH SOME FLURRIES OR LIGHT SNOW E OF A SFC TROF
BISECTING THE FA WITH VFR W OF THE TROF AT THE BEGINNING OF THE
FORECAST. EXPECT THESE CONDITIONS TO PERSIST UNTIL AFTER 12Z WHEN
AN IMPROVEMENT TO VFR IS EXPECTED. THE EXCEPTION WILL BE DLH AND
HYR WHERE MVFR WILL CONTINUE UNTIL 21Z AT DLH AND LAST THROUGH THE
FORECAST PERIOD AT HYR WITH PERIODS OF LES SHOWERS.
&&
.PREV DISCUSSION... /ISSUED 612 PM CDT MON MAR 11 2013/
AVIATION...00Z TAFS.
A MIX OF MVFR AND VFR THROUGH THE FORECAST AS CLOUDS WILL BE
DIFFICULT TO TIME. OFF AND ON FLURRIES ARE ALSO EXPECTED WITH A
PREDOMINATE LIGHT SNOW POSSIBLE AT HYR AS SOME LAKE EFFECT SNOW
SHOWERS PASS THROUGH. A GUSTY NW SFC WIND WILL DEVELOP AROUND 12Z
AT ALL SITES BUT HYR.
PREV DISCUSSION... /ISSUED 317 PM CDT MON MAR 11 2013/
SHORT TERM...CWA REMAINS UNDER THE INFLUENCE OF A CYCLONIC
CIRCULATION TO THE EAST OF THE REGION. ORGANIZED FORCING IN THE
FORM OF WEAK FRONTOGENESIS HAS KEPT MORE PERSISTENT SNOW OVER ERN
EDGE OF REGION. ELSEWHERE...ABUNDANT CLOUD COVER AND A FEW
FLURRIES ARE OCCURRING.
TONIGHT...AN AMPLIFYING MID LVL SYSTEM WILL TRACK FROM SRN
MANITOBA TO JUST SOUTH OF THE BRD LAKES VICINITY. IT IS DIFFICULT
TO FIND MUCH IN THE WAY OF A SFC REFLECTION ASSOCIATED WITH THIS
FEATURE EITHER IN THE PRESSURE OR WIND FIELDS. USED A BLEND OF THE
SREF AND EC TO KEEP POPS FOCUSED IN TWO AREAS. FIRST...ACROSS THE
SRN TIER OF ZONES CLOSER TO TRACK OF UPPER FEATURE. SECOND...AS
COLDER AIR MOVES ACROSS LAKE SUPERIOR...SOME INCREASE IN LES MAY
OCCUR OVER ERN WISC SNOWBELTS.
TOMORROW...UPPER LOW SCOOTS QUICKLY SE OF REGION BY MIDDAY WITH
DEEPENING OF NLY FLOW ACROSS CWA. MOST PROBABLE AREAS FOR PRECIP
WILL BE OVER ARROWHEAD AND WISC SNOWBELTS. A WRAPAROUND LOBE OF
DEEP LAYER MOISTURE ASSOCIATED WITH A MIGRATORY SHORTWAVE TROF
WILL ROTATE WESTWARD INTO ARROWHEAD DURING THE DAY. THIS IS
REFLECTED IN THE EC AND THE SPC WRF/NMM. 85H THERMAL TROUGH
SETTLES SOUTHWARD ACROSS LAKE SUPERIOR IN THE AFTERNOON. NEARLY
UNIDIRECTIONAL FLOW IN SFC/85H LAYER COMBINED WITH INCREASINGLY
FAVORABLE SYNOPTIC SCALE MOISTURE WILL PROMOTE ADDITIONAL SNOW
INTO SNOWBELTS. MAY NEED TO CONSIDER AN ADVISORY FOR LATE
AFTERNOON INTO EVENING.
TUESDAY NIGHT THROUGH MONDAY.
THE NORTHLAND WILL CONTINUE TO BE INFLUENCED BY A TROUGH TUESDAY
NIGHT...WITH SOME LIGHT SNOW OR FLURRIES WILL LINGERING TUESDAY
EVENING...BUT DIMINISHING OVERNIGHT. LITTLE ACCUMULATION IS EXPECTED
FOR MOST AREAS. THE EXCEPTION WILL BE ALONG THE SOUTH SHORE...MAINLY
THE SNOWBELT REGION OF ASHLAND/IRON COUNTIES. CHANCES FOR LAKE
EFFECT SNOW SHOWERS LOOK PRETTY GOOD WITH NORTHERLY WINDS AND 850MB
TEMPERATURES DROPPING TO AROUND -14C TO -16C. WE INCREASED POPS AND
SNOW AMOUNTS ACROSS ASHLAND/IRON COUNTIES TUESDAY NIGHT...WITH THE
BEST CHANCE FROM 00Z WED TO ABOUT 09Z WED. INVERSION LEVELS DROP
LATE AND DRIER AIR MOVES OVER THE LAKE LATE TUESDAY NIGHT AND
THROUGH WEDNESDAY. WINDS WILL ALSO BACK WEDNESDAY. AN ADVISORY MAY
BE NEEDED FOR IRON AND ASHLAND COUNTIES.
A WEST NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE REST OF
PERIOD WITH SEVERAL SHORTWAVES MOVING THROUGH AND BRINGING PERIODIC
CHANCES FOR PRECIPITATION. MOST OF THE SHORTWAVES WILL ONLY BRING
LIGHT PRECIPITATION.
WE HAVE A CHANCE FOR LIGHT SNOW WEDNESDAY NIGHT INTO THURSDAY AS WAA
MOVES THROUGH THE AREA. THE PRECIP LOOKS RATHER LIGHT...AND PRECIP
TYPE COULD BE IN QUESTION. 850MB TEMPS ARE FORECAST TO RISE TO
AROUND +4C OVER OUR SOUTHWEST ZONES BY 00Z FRI...AND REMAIN AROUND
-4C FAR NORTHEAST. FORECAST SOUNDINGS ALSO SHOW THE MOIST LAYER IS
RATHER LIMITED...WITH ICE CRYSTAL PRESENCE IN QUESTION. LATER SHIFTS
MAY HAVE TO ADD SOME MIXED PRECIP ONCE WE GET CLOSER.
A MORE SIGNIFICANT CLIPPER SYSTEM IS FORECAST BY THE ECMWF TO AFFECT
THE NORTHLAND FRIDAY INTO FRIDAY NIGHT...WITH THE GFS ABOUT 12 HOURS
FASTER. A MIX COULD BE POSSIBLE ONCE AGAIN...ESPECIALLY OVER THE
SOUTHERN HALF. A FEW INCHES OF SNOW WILL BE POSSIBLE WITH THIS
SYSTEM. THE GFS SHOWS THE CORE OF THE PRECIPITATION FURTHER NORTH
THAN THE ECMWF. BOTH THE GFS AND ECMWF DO SHOW COLDER AIR MOVING IN
BEHIND THIS CLIPPER...LASTING INTO THE WEEKEND.
HIGH TEMPERATURES WILL RANGE FROM THE UPPER TWENTIES TO LOWER
THIRTIES WEDNESDAY. THEY WILL WARM INTO THE LOWER TO MID THIRTIES
THURSDAY/FRIDAY...AND COOL A BIT BEHIND THE CLIPPER OVER THE WEEKEND.
AVIATION...18Z TAFS
MIX OF MVFR AND LOW VFR CONDITIONS COVERED THE NORTHLAND EARLY
THIS AFTERNOON...WITH SOME LIGHT SNOW OR FLURRIES IN SPOTS.
OVERALL...WE EXPECT THESE CONDITIONS TO CONTINUE THROUGH THE
PERIOD. THE RUC 900-925MB PRESSURE DEFICITS WERE INDICATING SOME
DECREASE IN CLOUD COVER THIS EVENING...BUT JUST DON`T HAVE THE
CONFIDENCE TO DIMINISH CEILINGS TOO MUCH. A CLIPPER MAY SPREAD
ADDITIONAL CLOUDS AND PERHAPS SOME ADDITIONAL LIGHT SNOW TO THE
REGION TONIGHT.
&&
.POINT TEMPS/POPS...
DLH 11 30 16 34 / 10 0 10 30
INL 6 29 14 35 / 10 0 20 20
BRD 10 30 17 36 / 10 10 20 20
HYR 12 32 14 36 / 20 10 10 30
ASX 15 30 16 35 / 30 10 0 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....DAP
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
325 PM CDT TUE MAR 12 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY.
MOSTLY CLOUDY CONDITIONS HAD DEVELOPED THROUGH THE DAY IN THE
NORTHEASTERN 2/3 OF THE FORECAST AREA...WITHIN AN AREA CYCLONIC
NORTHWESTERLY FLOW AROUND STRONG CLOSED LOW PRESSURE ACROSS THE
WESTERN GREAT LAKES. A FEW FLURRIES HAD DEVELOPED IN NORTHEAST
NEBRASKA AND NORTHWEST IOWA...BUT MORE IMPORTANTLY...WINDS GUSTING
30 TO 35 MPH HAS ALSO CREATED AREAS OF BLOWING SNOW OUT IN OPEN
RURAL AREAS. THIS WAS CREATING SOME VISIBILITY ISSUES...AS WELL
AS SOME SLICK ROADWAYS. THIS TREND WILL CONTINUE THROUGH EARLY
EVENING UNTIL THE WINDS BEGIN TO DIMINISH BY 5 TO 7 PM...ALTHOUGH
ISOLATED FLURRIES COULD STILL BE POSSIBLE IN WESTERN IOWA FOR
ANOTHER HOUR OR TWO BEYOND THAT. CLOUD TRENDS OVERNIGHT WILL BE
ALSO BE TRICKY TO FORECAST. SURFACE HIGH PRESSURE RIDGE WILL
CONTINUE MOVING IN FROM THE WEST. THIS WILL ALLOW SOME OF THE
DIURNAL CLOUDS TO DISSIPATE ON THE SOUTHWEST EDGE...HOWEVER AS
WITH PAST SEVERAL SYSTEMS...THE RAP SEEMS TO HAVE A MUCH BETTER
HANDLE ON THE LOW LEVEL CLOUDINESS...LINGERING IT MUCH LONGER THAN
OTHER MODELS WOULD SUGGEST. THIS COULD ALSO AFFECT HOURLY
TEMPERATURES...AS SKIES CLEAR IN SOME AREAS AND WINDS BECOME LIGHT
AND PERHAPS EVEN CALM IN OUR WESTERN CWA. SOME CIRRUS COULD ALSO
BEGIN TO MOVE INTO THESE SAME AREAS TOWARD DAYBREAK...AS AREAS
ALONG/EAST OF THE MISSOURI RIVER FINALLY BEGIN TO SCATTER OUT.
SOUTHEASTERLY SURFACE FLOW DEVELOPS ON WEDNESDAY AS THE MID/HIGH
CLOUDS MOVE ACROSS THE REGION. TEMPS SHOULD WARM INTO THE MID 30S
OVER THE SNOWFIELD, AND THE LOWER/MID 40S ELSEWHERE.
MEANWHILE...WARM AIR ADVECTION ALOFT WILL CONTINUE THROUGH THE
REMAINDER OF THE PERIOD. ANOTHER WEAK CLIPPER SYSTEM WILL MOVE
THROUGH THE DAKOTAS WEDNESDAY NIGHT. WHILE THIS COULD GENERATE A
SPRINKLE OR TWO IN OUR AREA AND MAYBE EVEN MEASURABLE PRECIP JUST
TO OUR NORTH/NORTHEAST...WILL MAINTAIN A DRY FORECAST AT THIS
TIME WITH PARTLY TO MOSTLY CLOUDY SKIES EXPECTED. THIS SHOULD
TRANSLATE TO DECENT WARMING ON THURSDAY...UPPER 40S OVER THE
DIMINISHING SNOW PACK...WHICH IS STILL UNDER MAV/MET GUIDANCE...
TO THE LOWER 60S OVER THE SNOW FREE AREAS. FRIDAY SHOULD BE THE
WARMEST DAY OF THE WEEK AS TEMPERATURES WARM SIGNIFICANTLY AHEAD
OF THE NEXT COLD FRONT EXPECTED FOR THE WEEKEND. TEMPS FRIDAY
SHOULD REACH THE MID 50S WHERE SOME SNOW STILL EXISTS...AND EVEN
IN THE MID TO UPPER 60S ELSEWHERE.
DEWALD
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
THE EXTENDED PERIOD LOOKS TO BE A PERIOD OF BELOW NORMAL
TEMPERATURES WITH UNSETTLED WEATHER SATURDAY THROUGH MONDAY. WEATHER
DISTURBANCES MOVING THROUGH THE WEST AND NORTHWEST FLOW ALOFT AND
WILL BRING CHANCES OF PRECIPITATION. THE LONG RANGE MODELS ARE NOT
IN GOOD AGREEMENT IN SPECIFIC TIMING AND STRENGTH OF THE
SYSTEMS...THUS LOW CONFIDENCE IN PINNING DOWN THE THERMAL STRUCTURE
AND TIMING. A WEAK WAVE APPEARS TO MOVE THROUGH THE CENTRAL/NORTHER
PLAINS SATURDAY AND SATURDAY NIGHT...AND THE GFS LINGERS IT INTO
SUNDAY...WITH SNOW...SLEET...AND RAIN POSSIBLE. SUNDAY NIGHT INTO
MONDAY...ANOTHER STRONGER SYSTEM MOVES THROUGH. THE EC IS STRONGER
WITH THE WAVE...FARTHER NORTH WITH THE PRECIP AND MOVES IT THROUGH
FASTER WITH MORE COLD AIR AND STRONGER WINDS AVAILABLE. FOR NOW HAVE
CHANCE POPS FOR RAIN OR SNOW MENTIONED FOR SUNDAY NIGHT AND MONDAY.
ZAPOTOCNY
&&
.AVIATION...18Z TAFS FOR KOFK...KOMA AND KLNK.
AREA OF MVFR CIGS AND LIGHT SNOW CONTINUES TO DROP SOUTHEAST
ACROSS EASTERN NEBRASKA AND WESTERN IOWA...WITH KLNK ON THE EDGE.
NORTHWEST SFC WINDS 15-25 MPH WITH GUSTS TO 30 MPH WILL CONTINUE
THROUGH 00Z AND BEGIN TO SUBSIDE THEREAFTER. VFR CONDITIONS ARE
EXPECTED AFTER 06Z AT ALL THREE SITES.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
812 PM EDT WED MAR 13 2013
.SYNOPSIS...
COLD NORTHWEST WINDS FLOWING OVER THE RELATIVELY WARM WATERS OF
LAKE ONTARIO WILL BRING SNOW SHOWERS TO THE AREA TONIGHT INTO
THURSDAY. A FEW INCHES OF SNOW COULD ACCUMULATE OVER OUR NORTHERN
COUNTIES... WITH LESS TO THE SOUTH. HIGH PRESSURE WILL BRING DRY
WEATHER THURSDAY NIGHT INTO FRIDAY... THEN THE NEXT STORM SYSTEM
APPROACHING FROM THE WEST WILL BRING A CHANCE OF LIGHT SNOW OR
MIXED PRECIPITATION BY LATE FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
SNOW SHOWERS ASSOCIATED WITH A POOL OF COLD AIR ALOFT WILL MOVE
ACROSS THE AREA LATE THIS AFTERNOON THROUGH MID-EVENING... WITH
SNOW SHOWERS DIMINISHING AFTER SUNSET. LATEST RAP SHORT-RANGE
FORECAST SOUNDINGS ARE STILL SHOWING SOME CAPE... GENERALLY 50 TO
150 J/KG ALONG WITH STEEP LOW-LEVEL LAPSE RATES. AS A RESULT SOME
REPORTS OF THUNDER HAVE BEEN RECEIVED FROM THE HEAVIEST SNOW
SHOWERS. WILL HAVE TO WATCH FOR SOME LOCALIZED AREAS OF SLICK
TRAVEL EARLY THIS EVENING AS ANY HEAVIER SQUALL COULD BRING A
QUICK COATING TO AN INCH OF SNOW ALONG WITH TEMPERATURES FALLING
TO NEAR OR JUST BELOW FREEZING.
SOME LAKE EFFECT SNOW BANDS WILL DEVELOP LATER THIS EVENING
THROUGH THE OVERNIGHT HOURS AS LOSS OF DIURNAL HEATING ALLOWS FOR
MORE ORGANIZATION OF THE RADAR ECHOES. LATEST GUIDANCE INDICATES
THAT 850 MB TEMPERATURES WILL FALL ALL THE WAY TO -20 C LATE
TONIGHT WHICH CERTAINLY WILL BE COLD ENOUGH FOR SOME LAKE EFFECT
GIVEN ADEQUATE SYNOPTIC-SCALE MOISTURE WHICH WILL ALSO BE IN
PLACE. FLOW WILL BE FROM AROUND 270 DEGREES LATE THIS EVENING
WHICH WILL FAVOR ANY ORGANIZED BAND TO BE NORTH OF SYRACUSE AND
THE THRUWAY. LATER TONIGHT THE FLOW SHIFTS TO BETWEEN 300 AND 310
DEGREES WHICH WILL FAVOR MULTIBANDS ACROSS A WIDE SECTION OF
CENTRAL NY. AT THIS POINT EXPECTING 2 OR 3 INCHES ACROSS MUCH OF
THE NORTHERN 1/3 OF THE FORECAST AREA BY THURSDAY MORNING.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
SNOW SHOWERS WILL CONTINUE THURSDAY WITH A FLOW VECTOR FROM AROUND
300 DEGREES. ANOTHER COUPLE OF INCHES COULD FALL OVER THE NORTHERN
1/3 OF THE FORECAST AREA THROUGH LATE MORNING. DURING THE
AFTERNOON EXPECT SNOW SHOWERS TO BECOME DISORGANIZED WITH
INCREASING DIURNAL HEATING. 850 MB TEMPERATURES WILL RISE ONLY
SLIGHTLY DURING THE DAY AND ENOUGH SYNOPTIC SCALE MOISTURE WILL
REMAIN IN PLACE TO KEEP SOME SNOW SHOWERS GOING INTO THURSDAY
EVENING. TEMPERATURES WILL LIKELY REMAIN BELOW FREEZING ACROSS THE
ENTIRE AREA THROUGH THURSDAY DESPITE THE STRONG MARCH SUNSHINE.
A WEAK RIDGE OF HI PRESSURE WILL BRING A PERIOD OF DRY WEATHER
THURSDAY NIGHT INTO FRIDAY MORNING. LOW PRESSURE WILL TRACK ACROSS
SOUTHERN CANADA ON FRIDAY... DRAGGING A FRONTAL BOUNDARY SOUTH
ACROSS THE AREA DURING THE AFTERNOON. SOME MOISTURE STREAKING OUT
AHEAD OF AN APPROACHING CLIPPER SYSTEM MAY TRAIN ALONG THIS FRONT
FRIDAY AFTERNOON ALLOWING FOR SOME LIGHT SNOW OR A MIX OF LIGHT
RAIN AND SNOW TO BREAK OUT ACROSS THE AREA DURING THE DAY.
TEMPERATURES WILL RECOVER BACK ABOVE FREEZING FRIDAY AFTERNOON SO
THAT ANY SNOW THAT DOES FALL WILL LIKELY NOT ACCUMULATE MUCH.
CLIPPER SYSTEM PASSES SOUTH OF OUR AREA FRIDAY NIGHT INTO
SATURDAY. MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE TRACK
AND INTENSITY OF THIS SYSTEM... AND AS OF NOW IT LOOKS LIKE THIS
SYSTEM WILL PRODUCE A PERIOD OF ACCUMULATING SNOW FRIDAY NIGHT
INTO SATURDAY MORNING ACROSS AT LEAST A PORTION OF THE AREA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A HIGHLY ACTIVE PATTERN WILL DOMINATE THE NORTHERN HEMISPHERE
DURING THIS PERIOD WITH A SERIES OF FRONTAL SYSTEMS AND LOW
PRESSURE SYSTEMS PASSING THROUGH...OR NEAR THE NORTHEASTERN
AND MID-ATLANTIC STATES.
THE INITIAL WAVE IN THE SERIES IS HANDLED DIFFERENTLY BY THE GFS
AND ECMWF MODEL TRENDS. THE 13/00Z EC WOULD BRING A PERIOD OF SNOW
THROUGH PA AND SOUTHERN NY DURING SUNDAY AFTERNOON AND EVENING
WHILE THE 13/12Z GFS REMAINS SUPPRESSED FURTHER SOUTH. THE 13/12Z
CANADIAN GGEM MODEL LEANS WITH A DRIER SOLUTION FOR THIS REGION.
AT THIS TIME IT IS PRUDENT TO MENTION A CHANCE OF PRECIP EXTENDING
ACROSS NEPA AND THE SOUTHERN HALF OF CNY.
A MORE SUBSTANTIAL SYSTEM IS GENERALLY AGREED UPON WITHIN THE
MODEL SOLUTIONS TO SLIDE THROUGH THE REGION LATER MONDAY INTO
TUESDAY AS AN OCCLUDED SYSTEM. THE GFS IS A LITTLE MORE WRAPPED UP
AND FURTHER N/W. THE SYSTEM GENERALLY LOOKS MILD WITH RAIN...ALTHOUGH
A MIX WITH SNOW IS STILL HIGHLY POSSIBLE. THIS SYSTEM WILL ALSO
USHER IN AN ANOMALOUSLY SHOT OF COLD AIR TO THE REGION FOR THE
LATTER HALF OF THE WEEK.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
CONVECTIVE SNOW SHOWER ACTIVITY HAS DIED DOWN THIS EVENING AS
DAYTIME THERMALS HAVE DISAPPEARED. HOWEVER THERE IS STILL THE
SLIGHT CHANCE FOR A VERY BRIEF PERIOD OF IFR RESTRICTIONS IN
STRAY SNOW SHOWER ACTIVITY THROUGH THE NEXT FEW HOURS.
A LAKE EFFECT SNOW BAND WILL DROP ACROSS THE RME TERMINAL BETWEEN
4Z AND 7Z, AND THEN TOWARD THE SYR TERMINAL BY 8Z. ADDITIONAL SNOW
SHOWER ACTIVITY WILL DEVELOP DOWNSTREAM. LOW MVFR TO IFR
CONDITIONS WILL AFFECT THE TERMINALS IN LAKE SNOWS.
WINDS WILL BECOME GUSTY TOWARD SUNRISE. NORTHWEST WINDS WILL GUST
TO 20 TO 30 KNOTS THROUGHOUT THE MORNING AND AFTERNOON HOURS.
.OUTLOOK...
FRIDAY NIGHT/SATURDAY EVE...RESTRICTIONS POSSIBLE IN LIGHT SNOW.
SUNDAY...VFR.
MONDAY...BECOMING MVFR IN A RAIN/SNOW MIX.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MSE
NEAR TERM...MSE
SHORT TERM...MSE
LONG TERM...JAB
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
202 PM EDT TUE MAR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL BRING MODERATE TO BRIEFLY HEAVY RAIN
TODAY AND POSSIBLE MINOR FLOODING ACROSS CENTRAL AND SOUTHERN
VERMONT AND ESSEX COUNTY NEW YORK THIS AFTERNOON THROUGH TONIGHT.
PRECIPITATION ENDS AS A BRIEF PERIOD OF WET SNOW TONIGHT AS THE
COLD FRONT PUSHES EAST THROUGH THE REGION USHERING IN COOLER
TEMPERATURES. TEMPERATURES CLOSER TO SEASONAL LEVELS FOR MID-
MARCH ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK. A LINGERING
UPPER DISTURBANCE WILL BRING SNOW SHOWERS TO THE REGION WEDNESDAY
NIGHT AND THURSDAY RESULTING IN MINOR SNOW ACCUMULATIONS IN THE
VALLEYS...WITH SEVERAL INCHES EXPECTED ACROSS THE NORTHERN
ADIRONDACKS AND NORTHERN GREEN MOUNTAINS.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 111 PM EDT TUESDAY...CURRENT FORECAST IS ON TRACK...NO
CHANGES MADE FOR THIS MORNING UPDATE. PREVIOUS DISCUSSION
FOLLOWS.
WIDESPREAD RAINFALL EXPECTED TODAY WITH CONTINUED BREEZY AND MILD
TEMPERATURES THIS MORNING (50F AT BTV AT 11Z)...THEN LESS WIND
THIS AFTN. THE NORTH COUNTRY REMAINS IN PREVAILING DEEP-LAYER SLY
FLOW IN ADVANCE OF SLOW- MOVING OCCLUSION NOW ACROSS W-CENTRAL
NY. RUC ANALYSIS SHOWS PW PLUME OF 0.9 TO 1.0" PRECEDING THE
FRONT ACROSS NRN NY AND WILL SHIFT SLOWLY EWD ACROSS VT THIS
AFTN. NOTED OVERALL MODEST INCREASE IN QPF PER 00Z GUIDANCE
SUITE...ESPECIALLY AS SECONDARY WAVE LOW DEVELOPS ALONG THE
OCCLUSION THIS AFTN AND TRACKS NNEWD ACROSS WRN NEW ENGLAND THIS
AFTN. ADDED MENTION OF HEAVY RAIN ACROSS SRN HALF OF CWA THIS
AFTN BASED ON POSSIBLE 0.5-0.6" RAINFALL IN 6 HR PERIOD.
THIS INCREASE IN RAINFALL AMTS -- COMBINED WITH 3-DAYS OF TEMPS
WELL-ABOVE AVERAGE AND ASSOCIATED SNOW MELT -- HAS WARRANTED
ISSUANCE OF FLOOD WATCH FOR ROUGHLY SRN HALF OF THE CWA. ISSUED
WATCH FOR THOSE COUNTIES WHERE BASIN-AVERAGED STORM TOTAL
RAINFALL IS EXPECTED TO EXCEED 1"...WHICH INCLUDES ESSEX COUNTY
NY AND CENTRAL/S-CENTRAL VT EWD TO CALEDONIA COUNTY AND POINTS
SOUTH. RIVER FLOODING WILL GENERALLY BE IN THE MINOR
CATEGORY...BUT WITH ADDED UNCERTAINTY OF BREAK-UP/MOVING RIVER
ICE...THERE COULD BE SOME LOCALIZED GREATER FLOODING
THREAT...ESPECIALLY ON SMALLER STEMS.
HIGH TEMPERATURES WILL GENERALLY OCCUR THIS MORNING WITH TEMPS
AREAWIDE MOSTLY IN THE 40S TO NEAR 50 IN THE CHAMPLAIN VALLEY.
SOUTH WINDS STILL LOCALLY GUSTY ESPECIALLY ACROSS THE HIR TRRN.
LOWER ELEVATION WINDS WILL GRADUALLY SUBSIDE TODAY AS RAINFALL
TENDS TO STABILIZE PBL AND P-GRADIENT FLATTENS THIS AFTN WITH
DEVELOPMENT OF SFC WAVE TO OUR SOUTH.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH THURSDAY/...
AS OF 415 AM EDT TUESDAY...SFC OCCLUSION SHIFTS EWD ACROSS THE
REGION AND LIKELY SHIFTS ACROSS THE CHAMPLAIN VALLEY AROUND
00Z...AND THEN EAST OF THE CT RIVER BY 06Z. VERTICAL TEMP PROFILE
COOLS ABRUPTLY...AND ANTICIPATE A FEW HOURS OF WET SNOW BEFORE
PRECIPITATION ENDS THIS EVENING UNTIL ABOUT MIDNIGHT CENTRAL VT
AND POINTS WEST...AND PERHAPS HANGING ON IN ERN VT AS LATE AS
09Z. SHOULD SEE A COATING TO AN INCH MOST LOCATIONS...BUT LOCALLY
UP TO 2" ACROSS THE NORTHEAST KINGDOM AS WAVE LOW DEEPENS TO THE
EAST ACROSS NRN NH/ME. OVERNIGHT LOWS GENERALLY IN THE UPR 20S TO
LOWER 30S...BUT A FEW COLDER READINGS ARE EXPECTED IN THE NRN
ADIRONDACKS WITH COLDER 850MB TEMPS PUSHING IN FROM THE WEST. A
FEW BREAKS IN THE OVERCAST ARE POSSIBLE BY DAYBREAK ACROSS
S-CENTRAL VT AND THE ST. LAWRENCE VALLEY.
WEDNESDAY WILL GENERALLY BE A MOSTLY CLOUDY DAY BUT NOT
ANTICIPATING MUCH IN THE WAY OF SNOW SHOWER ACTIVITY UNTIL LATE
IN THE DAY ACROSS NRN NY. TRAILING 500MB TROUGH KEEPS MID-LEVEL
FLOW S/SW ACROSS THE REGION UNTIL WEDNESDAY NIGHT...AND AT THAT
POINT WE SHOULD SEE AN INCREASE IN THE OROGRAPHIC SNOW SHOWER
ACTIVITY ACROSS THE NRN ADIRONDACKS AND NRN GREENS. HAVE
GENERALLY DRY BUT CLOUDY CONDITIONS WED WITH HIGHS IN THE UPR 30S
TO LOWER 40S. WED NIGHT INTO THU AM...BETTER POTL FOR SNOW
SHOWERS AND HAVE RAISED POPS TO LIKELY ACROSS THE NRN ADIRONDACKS
AND NRN GREENS. SNOWFALL AMTS WILL BE LARGELY ELEVATION
DEPENDENT...BUT BY THU MORNING LOOKING AT JUST A DUSTING TO AN
INCH IN THE CHAMPLAIN/CT/ST LAWRENCE VALLEY BUT LOCALLY 2-4" IN
THE NRN ADIRONDACKS AND NRN GREENS. LOWS WEDNESDAY NIGHT MOSTLY
IN THE LOWER 20S...WITH TEENS IN NRN NY. HIGHS THURSDAY WILL BE
BELOW AVG AND GENERALLY 28-32F...WITH MID 20S ACROSS NRN NY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 451 AM EDT MONDAY... FAIRLY GOOD CONGRUENCE EXISTS BETWEEN
00Z GLOBAL MODELS THROUGH THE UPCOMING WEEKEND. CLOSED UPPER LOW
GRADUALLY BEGINS TO LIFT OUT/DE-AMPLIFY THURSDAY NIGHT INTO FRIDAY
WITH UPPER-LEVEL FLOW BECOMING MORE QUASI-ZONAL. A WEAK CLIPPER
MOVES IN LATE FRIDAY NIGHT INTO SATURDAY EXITING THE NORTH
COUNTRY ON SATURDAY NIGHT. SIGNIFICANT DIFFERENCES THEN BEGIN TO
APPEAR SUNDAY NIGHT INTO EARLY NEXT WEEK REGARDING UPPER- LEVEL
ENERGY EJECTION INTO THE CENTRAL AND EASTERN CONUS AND ASSOCIATED
SFC DEVELOPMENT.
UPSLOPE SNOW SHOWERS CONTINUE INTO THURSDAY NIGHT WITH CLEARING
EXPECTED BY FRIDAY. ANY SNOW ACCUMULATION LIMITED TO THE HIGHER
TERRAIN AND LIKELY NOT AMOUNTING TO MUCH MORE THAN A DUSTING TO
2". MDT-STG COLD ADVECTION WITH 925MB TEMPS FALLING TO -8 TO -12C
WITH BELOW NORMAL LOWS FOR THURSDAY NIGHT (UPPER SINGLE DIGITS TO
THE TEENS IN THE WARMER VALLEYS).
WEAK LOW-LEVEL WARM ADVECTION BEGINS AHEAD OF APPROACHING CLIPPER
SYSTEM FOR FRIDAY NIGHT. SLIGHT CHANCE TO CHANCE PRECIPITATION
PROBABILITIES FRIDAY NIGHT BECOMING ALL CHANCE/HIGH CHANCE FOR
SATURDAY...WITH SLIGHTLY HIGHER PROBABILITIES LOCATED ACROSS
SOUTHERN VERMONT. EXPECTING MOSTLY SNOW SHOWERS BUT A RAIN/SNOW
MIX IS EXPECTED IN THE VALLEYS DURING THE AFTERNOON. OROGRAPHIC
SNOW SHOWERS FOR SATURDAY NIGHT. SATURDAY NIGHT ALSO LOOKS TO BE
RATHER COLD FOR MID- MARCH UNDER MDT- STG COLD ADVECTION (925MB
TEMPERATURES FALLING TO -12 TO -14C).
FAIRLY QUIET UNTIL MONDAY WHERE DIFFERENCES BETWEEN 00Z GFS/ECMWF
CLOUDS THE FORECAST. NOTABLY...THE ECMWF SHOWING A STRONGER
SHORTWAVE TROUGH DIGGING INTO THE ROCKIES WITH A SIGNIFICANT
CENTRAL/EASTERN CONUS STORM SYSTEM WHILE THE GFS OFFERS A
WEAKER/LESS PHASED SOLUTION. PREFERENCE IS TOWARD THE MORE
CONSISTENT 00Z ECMWF FOR THIS PERIOD. IF CORRECT...THIS WOULD BE
A FAIRLY MILD SYSTEM WITH POTENTIAL FOR PRECIPITATION TYPE
CHANGES BUT WITH SPECIFIC DETAILS TO EVOLVE IN THE COMING DAYS.
THEREFORE HAVE SLIGHT CHANCE PRECIPITATION PROBABILITIES THROUGH
MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...COLD FRONT CONTINUING TO TRAVERSE OVER
THE NORTH COUNTRY AND PRODUCE RAIN AND VRB CONDITIONS THIS
AFTERNOON INTO EVENING. SURGE OF MODERATE TO HEAVY PRECIP MOVING
NORTHWARD FROM CENTRAL AND ERN NY THIS AFTERNOON. THIS WILL BRING
WIDESPREAD MVFR CONDITIONS THROUGH THE EVENING HOURS. AS FRONT
GRADUALLY MOVES EAST...SO WILL BACK EDGE OF PRECIP...WITH KMSS
EXPECTING DRY AND IMPROVING CONDITIONS TO MVFR/VFR AROUND 02Z.
MVFR/IFR CONDITIONS AT KSLK WILL PERSIST THROUGH THE EARLY
OVERNIGHT PERIOD WITH SW FLOW KEEPING MVFR CIGS OVER THE TAF
SITE. IN THE CPV...WINDS BEING CHANNELED UP THE VALLEY...HELPING
TO KEEP VFR CONDITIONS WITH TEMPO FOR MVFR CIGS IN THE HEAVIER
PRECIP. EXPECT PRECIP TAPERING OFF IN CPV AFTER 04Z WITH VFR
CONDITIONS. AT KMPV...MVFR CONDITIONS WILL CONTINUE INTO THE
EVENING AND EARLY OVERNIGHT...WITH VFR CONDITIONS HOLDING OFF
UNTIL LATE MORNING HRS. IN KRUT...SE WINDS AND VFR CIGS WILL SEE
MVFR CIGS AT TIMES MAINLY IN AREAS OF PRECIP LATE THIS AFTN INTO
EVENING.
LLJ MOVING SLIGHTLY AHEAD OF THE COLD FRONT WILL PRODUCE LLWS AND
OR GUSTY WINDS THIS AFTERNOON. JET MOVES OUT OF ERN VT AROUND
00Z...AS WINDS BEHIND THE FRONT BRIEFLY BECM LGT AND VRB...BEFORE
SHIFTING OUT OF THE W. WINDS WILL RECOVER OUT OF THE W-NW AT
5-10KTS OVERNIGHT TOWARDS WEDNESDAY MORNING.
OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WEDNESDAY THROUGH 06Z FRIDAY...SCATTERED RAIN/SNOW SHOWERS
DEVELOP ACROSS THE REGION IN NW FLOW ALOFT...MOST PERSISTENT AT
MPV/SLK WITH OROGRAPHIC EFFECTS. PERIODS OF MVFR/IFR POSSIBLE.
06Z FRIDAY THROUGH 06Z SATURDAY...CONDITIONS IMPROVE TO VFR.
06Z SATURDAY THROUGH 06Z SUNDAY...LOWERING CEILINGS 06-12Z
SATURDAY WITH PERIODS OF MVFR/IFR POSSIBLE SATURDAY MORNING IN
LIGHT RAIN/SNOW ASSOCIATED WITH CLIPPER SYSTEM.
06Z SUNDAY ONWARD...VFR CONDITIONS WITH HIGH PRESSURE AT THE SFC.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR VTZ007>012-018-019.
NY...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NYZ034-035.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/NEILES
SHORT TERM...BANACOS
LONG TERM...LOCONTO
AVIATION...KGM
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
111 PM EDT TUE MAR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL BRING MODERATE TO BRIEFLY HEAVY RAIN
TODAY AND POSSIBLE MINOR FLOODING ACROSS CENTRAL AND SOUTHERN
VERMONT AND ESSEX COUNTY NEW YORK THIS AFTERNOON THROUGH TONIGHT.
PRECIPITATION ENDS AS A BRIEF PERIOD OF WET SNOW TONIGHT AS THE
COLD FRONT PUSHES EAST THROUGH THE REGION USHERING IN COOLER
TEMPERATURES. TEMPERATURES CLOSER TO SEASONAL LEVELS FOR MID-
MARCH ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK. A LINGERING
UPPER DISTURBANCE WILL BRING SNOW SHOWERS TO THE REGION WEDNESDAY
NIGHT AND THURSDAY RESULTING IN MINOR SNOW ACCUMULATIONS IN THE
VALLEYS...WITH SEVERAL INCHES EXPECTED ACROSS THE NORTHERN
ADIRONDACKS AND NORTHERN GREEN MOUNTAINS.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 111 PM EDT TUESDAY...CURRENT FORECAST IS ON TRACK...NO
CHANGES MADE FOR THIS MORNING UPDATE. PREVIOUS DISCUSSION
FOLLOWS.
WIDESPREAD RAINFALL EXPECTED TODAY WITH CONTINUED BREEZY AND MILD
TEMPERATURES THIS MORNING (50F AT BTV AT 11Z)...THEN LESS WIND
THIS AFTN. THE NORTH COUNTRY REMAINS IN PREVAILING DEEP-LAYER SLY
FLOW IN ADVANCE OF SLOW- MOVING OCCLUSION NOW ACROSS W-CENTRAL
NY. RUC ANALYSIS SHOWS PW PLUME OF 0.9 TO 1.0" PRECEDING THE
FRONT ACROSS NRN NY AND WILL SHIFT SLOWLY EWD ACROSS VT THIS
AFTN. NOTED OVERALL MODEST INCREASE IN QPF PER 00Z GUIDANCE
SUITE...ESPECIALLY AS SECONDARY WAVE LOW DEVELOPS ALONG THE
OCCLUSION THIS AFTN AND TRACKS NNEWD ACROSS WRN NEW ENGLAND THIS
AFTN. ADDED MENTION OF HEAVY RAIN ACROSS SRN HALF OF CWA THIS
AFTN BASED ON POSSIBLE 0.5-0.6" RAINFALL IN 6 HR PERIOD.
THIS INCREASE IN RAINFALL AMTS -- COMBINED WITH 3-DAYS OF TEMPS
WELL-ABOVE AVERAGE AND ASSOCIATED SNOW MELT -- HAS WARRANTED
ISSUANCE OF FLOOD WATCH FOR ROUGHLY SRN HALF OF THE CWA. ISSUED
WATCH FOR THOSE COUNTIES WHERE BASIN-AVERAGED STORM TOTAL
RAINFALL IS EXPECTED TO EXCEED 1"...WHICH INCLUDES ESSEX COUNTY
NY AND CENTRAL/S-CENTRAL VT EWD TO CALEDONIA COUNTY AND POINTS
SOUTH. RIVER FLOODING WILL GENERALLY BE IN THE MINOR
CATEGORY...BUT WITH ADDED UNCERTAINTY OF BREAK-UP/MOVING RIVER
ICE...THERE COULD BE SOME LOCALIZED GREATER FLOODING
THREAT...ESPECIALLY ON SMALLER STEMS.
HIGH TEMPERATURES WILL GENERALLY OCCUR THIS MORNING WITH TEMPS
AREAWIDE MOSTLY IN THE 40S TO NEAR 50 IN THE CHAMPLAIN VALLEY.
SOUTH WINDS STILL LOCALLY GUSTY ESPECIALLY ACROSS THE HIR TRRN.
LOWER ELEVATION WINDS WILL GRADUALLY SUBSIDE TODAY AS RAINFALL
TENDS TO STABILIZE PBL AND P-GRADIENT FLATTENS THIS AFTN WITH
DEVELOPMENT OF SFC WAVE TO OUR SOUTH.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH THURSDAY/...
AS OF 415 AM EDT TUESDAY...SFC OCCLUSION SHIFTS EWD ACROSS THE
REGION AND LIKELY SHIFTS ACROSS THE CHAMPLAIN VALLEY AROUND
00Z...AND THEN EAST OF THE CT RIVER BY 06Z. VERTICAL TEMP PROFILE
COOLS ABRUPTLY...AND ANTICIPATE A FEW HOURS OF WET SNOW BEFORE
PRECIPITATION ENDS THIS EVENING UNTIL ABOUT MIDNIGHT CENTRAL VT
AND POINTS WEST...AND PERHAPS HANGING ON IN ERN VT AS LATE AS
09Z. SHOULD SEE A COATING TO AN INCH MOST LOCATIONS...BUT LOCALLY
UP TO 2" ACROSS THE NORTHEAST KINGDOM AS WAVE LOW DEEPENS TO THE
EAST ACROSS NRN NH/ME. OVERNIGHT LOWS GENERALLY IN THE UPR 20S TO
LOWER 30S...BUT A FEW COLDER READINGS ARE EXPECTED IN THE NRN
ADIRONDACKS WITH COLDER 850MB TEMPS PUSHING IN FROM THE WEST. A
FEW BREAKS IN THE OVERCAST ARE POSSIBLE BY DAYBREAK ACROSS
S-CENTRAL VT AND THE ST. LAWRENCE VALLEY.
WEDNESDAY WILL GENERALLY BE A MOSTLY CLOUDY DAY BUT NOT
ANTICIPATING MUCH IN THE WAY OF SNOW SHOWER ACTIVITY UNTIL LATE
IN THE DAY ACROSS NRN NY. TRAILING 500MB TROUGH KEEPS MID-LEVEL
FLOW S/SW ACROSS THE REGION UNTIL WEDNESDAY NIGHT...AND AT THAT
POINT WE SHOULD SEE AN INCREASE IN THE OROGRAPHIC SNOW SHOWER
ACTIVITY ACROSS THE NRN ADIRONDACKS AND NRN GREENS. HAVE
GENERALLY DRY BUT CLOUDY CONDITIONS WED WITH HIGHS IN THE UPR 30S
TO LOWER 40S. WED NIGHT INTO THU AM...BETTER POTL FOR SNOW
SHOWERS AND HAVE RAISED POPS TO LIKELY ACROSS THE NRN ADIRONDACKS
AND NRN GREENS. SNOWFALL AMTS WILL BE LARGELY ELEVATION
DEPENDENT...BUT BY THU MORNING LOOKING AT JUST A DUSTING TO AN
INCH IN THE CHAMPLAIN/CT/ST LAWRENCE VALLEY BUT LOCALLY 2-4" IN
THE NRN ADIRONDACKS AND NRN GREENS. LOWS WEDNESDAY NIGHT MOSTLY
IN THE LOWER 20S...WITH TEENS IN NRN NY. HIGHS THURSDAY WILL BE
BELOW AVG AND GENERALLY 28-32F...WITH MID 20S ACROSS NRN NY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 451 AM EDT MONDAY... FAIRLY GOOD CONGRUENCE EXISTS BETWEEN
00Z GLOBAL MODELS THROUGH THE UPCOMING WEEKEND. CLOSED UPPER LOW
GRADUALLY BEGINS TO LIFT OUT/DE-AMPLIFY THURSDAY NIGHT INTO FRIDAY
WITH UPPER-LEVEL FLOW BECOMING MORE QUASI-ZONAL. A WEAK CLIPPER
MOVES IN LATE FRIDAY NIGHT INTO SATURDAY EXITING THE NORTH
COUNTRY ON SATURDAY NIGHT. SIGNIFICANT DIFFERENCES THEN BEGIN TO
APPEAR SUNDAY NIGHT INTO EARLY NEXT WEEK REGARDING UPPER- LEVEL
ENERGY EJECTION INTO THE CENTRAL AND EASTERN CONUS AND ASSOCIATED
SFC DEVELOPMENT.
UPSLOPE SNOW SHOWERS CONTINUE INTO THURSDAY NIGHT WITH CLEARING
EXPECTED BY FRIDAY. ANY SNOW ACCUMULATION LIMITED TO THE HIGHER
TERRAIN AND LIKELY NOT AMOUNTING TO MUCH MORE THAN A DUSTING TO
2". MDT-STG COLD ADVECTION WITH 925MB TEMPS FALLING TO -8 TO -12C
WITH BELOW NORMAL LOWS FOR THURSDAY NIGHT (UPPER SINGLE DIGITS TO
THE TEENS IN THE WARMER VALLEYS).
WEAK LOW-LEVEL WARM ADVECTION BEGINS AHEAD OF APPROACHING CLIPPER
SYSTEM FOR FRIDAY NIGHT. SLIGHT CHANCE TO CHANCE PRECIPITATION
PROBABILITIES FRIDAY NIGHT BECOMING ALL CHANCE/HIGH CHANCE FOR
SATURDAY...WITH SLIGHTLY HIGHER PROBABILITIES LOCATED ACROSS
SOUTHERN VERMONT. EXPECTING MOSTLY SNOW SHOWERS BUT A RAIN/SNOW
MIX IS EXPECTED IN THE VALLEYS DURING THE AFTERNOON. OROGRAPHIC
SNOW SHOWERS FOR SATURDAY NIGHT. SATURDAY NIGHT ALSO LOOKS TO BE
RATHER COLD FOR MID- MARCH UNDER MDT- STG COLD ADVECTION (925MB
TEMPERATURES FALLING TO -12 TO -14C).
FAIRLY QUIET UNTIL MONDAY WHERE DIFFERENCES BETWEEN 00Z GFS/ECMWF
CLOUDS THE FORECAST. NOTABLY...THE ECMWF SHOWING A STRONGER
SHORTWAVE TROUGH DIGGING INTO THE ROCKIES WITH A SIGNIFICANT
CENTRAL/EASTERN CONUS STORM SYSTEM WHILE THE GFS OFFERS A
WEAKER/LESS PHASED SOLUTION. PREFERENCE IS TOWARD THE MORE
CONSISTENT 00Z ECMWF FOR THIS PERIOD. IF CORRECT...THIS WOULD BE
A FAIRLY MILD SYSTEM WITH POTENTIAL FOR PRECIPITATION TYPE
CHANGES BUT WITH SPECIFIC DETAILS TO EVOLVE IN THE COMING DAYS.
THEREFORE HAVE SLIGHT CHANCE PRECIPITATION PROBABILITIES THROUGH
MONDAY.
&&
.AVIATION /17Z TUESDAY THROUGH SUNDAY/...
THROUGH 12Z WEDNESDAY...COLD FRONT CONTINUES TO APPROACH FROM THE
WEST WITH MAINLY LIGHT RAIN ALONG/AHEAD OF IT. GUSTS HAVE DROPPED
OFF SOME BUT EXPECT THE GUSTS TO INCREASE AGAIN EARLY THIS
MORNING. LLWS WILL ALSO CONTINUE TO REMAIN A RISK FOR MOST OF THE
TAFS UNTIL FRONTAL PASSAGE. VISIBILITIES IN THE SHOWERS HAVE BEEN
MAINLY 3-6SM AND WOULD EXPECT THIS TO CONTINUE. HIGH RES MODELS
CONTINUE TO SHOW ENHANCEMENT ACROSS CENTRAL/SOUTHERN VT JUST
BEFORE FRONTAL PASSAGE SO WILL NEED TO WATCH POTENTIAL FOR BRIEF
LOWER VISIBILITIES AT RUT AND MPV. FRONTAL PASSAGE EXPECTED
BETWEEN 18-23Z WITH DRIER CONDITIONS EXPECTED EXCEPT FOR SOME
LINGERING RAIN/SNOW SHOWERS AT SLK. WIND SHIFT TO WEST WITH
DROPOFF IN WIND SPEEDS AND GUSTS EXPECTED BEHIND THE FRONT.
THOUGH VISIBILITIES IMPROVE...CEILINGS WILL LIKELY STAY MVFR/VFR
THROUGH THE REST OF THE TAF PERIOD.
OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY...
12Z WEDNESDAY THROUGH 18Z WEDNESDAY...MAINLY MVFR/VFR DUE TO
LOWER CEILINGS AND WITH PERIODS OF RAIN/SNOW SHOWERS AT MPV/SLK.
18Z WEDNESDAY THROUGH 06Z FRIDAY...SCATTERED RAIN/SNOW SHOWERS
DEVELOP ACROSS THE REGION IN NW FLOW ALOFT...MOST PERSISTENT AT
MPV/SLK WITH OROGRAPHIC EFFECTS. PERIODS OF MVFR/IFR POSSIBLE.
06Z FRIDAY THROUGH 06Z SATURDAY...CONDITIONS IMPROVE TO VFR.
06Z SATURDAY ONWARD...LOWERING CEILINGS 06-12Z SATURDAY WITH PERIODS
OF MVFR/IFR POSSIBLE SATURDAY MORNING IN LIGHT RAIN/SNOW
ASSOCIATED WITH CLIPPER SYSTEM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR VTZ007>012-018-019.
NY...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NYZ034-035.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/NEILES
SHORT TERM...BANACOS
LONG TERM...LOCONTO
AVIATION...LOCONTO
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1025 AM EDT TUE MAR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL BRING MODERATE TO BRIEFLY HEAVY RAIN
TODAY AND POSSIBLE MINOR FLOODING ACROSS CENTRAL AND SOUTHERN
VERMONT AND ESSEX COUNTY NEW YORK THIS AFTERNOON THROUGH TONIGHT.
PRECIPITATION ENDS AS A BRIEF PERIOD OF WET SNOW TONIGHT AS THE
COLD FRONT PUSHES EAST THROUGH THE REGION USHERING IN COOLER
TEMPERATURES. TEMPERATURES CLOSER TO SEASONAL LEVELS FOR MID-
MARCH ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK. A LINGERING
UPPER DISTURBANCE WILL BRING SNOW SHOWERS TO THE REGION WEDNESDAY
NIGHT AND THURSDAY RESULTING IN MINOR SNOW ACCUMULATIONS IN THE
VALLEYS...WITH SEVERAL INCHES EXPECTED ACROSS THE NORTHERN
ADIRONDACKS AND NORTHERN GREEN MOUNTAINS.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 1023 AM EDT TUESDAY...CURRENT FORECAST IS ON TRACK...NO
CHANGES MADE FOR THIS MORNING UPDATE. PREVIOUS DISCUSSION
FOLLOWS.
WIDESPREAD RAINFALL EXPECTED TODAY WITH CONTINUED BREEZY AND MILD
TEMPERATURES THIS MORNING (50F AT BTV AT 11Z)...THEN LESS WIND
THIS AFTN. THE NORTH COUNTRY REMAINS IN PREVAILING DEEP-LAYER SLY
FLOW IN ADVANCE OF SLOW- MOVING OCCLUSION NOW ACROSS W-CENTRAL
NY. RUC ANALYSIS SHOWS PW PLUME OF 0.9 TO 1.0" PRECEDING THE
FRONT ACROSS NRN NY AND WILL SHIFT SLOWLY EWD ACROSS VT THIS
AFTN. NOTED OVERALL MODEST INCREASE IN QPF PER 00Z GUIDANCE
SUITE...ESPECIALLY AS SECONDARY WAVE LOW DEVELOPS ALONG THE
OCCLUSION THIS AFTN AND TRACKS NNEWD ACROSS WRN NEW ENGLAND THIS
AFTN. ADDED MENTION OF HEAVY RAIN ACROSS SRN HALF OF CWA THIS
AFTN BASED ON POSSIBLE 0.5-0.6" RAINFALL IN 6 HR PERIOD.
THIS INCREASE IN RAINFALL AMTS -- COMBINED WITH 3-DAYS OF TEMPS
WELL-ABOVE AVERAGE AND ASSOCIATED SNOW MELT -- HAS WARRANTED
ISSUANCE OF FLOOD WATCH FOR ROUGHLY SRN HALF OF THE CWA. ISSUED
WATCH FOR THOSE COUNTIES WHERE BASIN-AVERAGED STORM TOTAL
RAINFALL IS EXPECTED TO EXCEED 1"...WHICH INCLUDES ESSEX COUNTY
NY AND CENTRAL/S-CENTRAL VT EWD TO CALEDONIA COUNTY AND POINTS
SOUTH. RIVER FLOODING WILL GENERALLY BE IN THE MINOR
CATEGORY...BUT WITH ADDED UNCERTAINTY OF BREAK-UP/MOVING RIVER
ICE...THERE COULD BE SOME LOCALIZED GREATER FLOODING
THREAT...ESPECIALLY ON SMALLER STEMS.
HIGH TEMPERATURES WILL GENERALLY OCCUR THIS MORNING WITH TEMPS
AREAWIDE MOSTLY IN THE 40S TO NEAR 50 IN THE CHAMPLAIN VALLEY.
SOUTH WINDS STILL LOCALLY GUSTY ESPECIALLY ACROSS THE HIR TRRN.
LOWER ELEVATION WINDS WILL GRADUALLY SUBSIDE TODAY AS RAINFALL
TENDS TO STABILIZE PBL AND P-GRADIENT FLATTENS THIS AFTN WITH
DEVELOPMENT OF SFC WAVE TO OUR SOUTH.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH THURSDAY/...
AS OF 415 AM EDT TUESDAY...SFC OCCLUSION SHIFTS EWD ACROSS THE
REGION AND LIKELY SHIFTS ACROSS THE CHAMPLAIN VALLEY AROUND
00Z...AND THEN EAST OF THE CT RIVER BY 06Z. VERTICAL TEMP PROFILE
COOLS ABRUPTLY...AND ANTICIPATE A FEW HOURS OF WET SNOW BEFORE
PRECIPITATION ENDS THIS EVENING UNTIL ABOUT MIDNIGHT CENTRAL VT
AND POINTS WEST...AND PERHAPS HANGING ON IN ERN VT AS LATE AS
09Z. SHOULD SEE A COATING TO AN INCH MOST LOCATIONS...BUT LOCALLY
UP TO 2" ACROSS THE NORTHEAST KINGDOM AS WAVE LOW DEEPENS TO THE
EAST ACROSS NRN NH/ME. OVERNIGHT LOWS GENERALLY IN THE UPR 20S TO
LOWER 30S...BUT A FEW COLDER READINGS ARE EXPECTED IN THE NRN
ADIRONDACKS WITH COLDER 850MB TEMPS PUSHING IN FROM THE WEST. A
FEW BREAKS IN THE OVERCAST ARE POSSIBLE BY DAYBREAK ACROSS
S-CENTRAL VT AND THE ST. LAWRENCE VALLEY.
WEDNESDAY WILL GENERALLY BE A MOSTLY CLOUDY DAY BUT NOT
ANTICIPATING MUCH IN THE WAY OF SNOW SHOWER ACTIVITY UNTIL LATE
IN THE DAY ACROSS NRN NY. TRAILING 500MB TROUGH KEEPS MID-LEVEL
FLOW S/SW ACROSS THE REGION UNTIL WEDNESDAY NIGHT...AND AT THAT
POINT WE SHOULD SEE AN INCREASE IN THE OROGRAPHIC SNOW SHOWER
ACTIVITY ACROSS THE NRN ADIRONDACKS AND NRN GREENS. HAVE
GENERALLY DRY BUT CLOUDY CONDITIONS WED WITH HIGHS IN THE UPR 30S
TO LOWER 40S. WED NIGHT INTO THU AM...BETTER POTL FOR SNOW
SHOWERS AND HAVE RAISED POPS TO LIKELY ACROSS THE NRN ADIRONDACKS
AND NRN GREENS. SNOWFALL AMTS WILL BE LARGELY ELEVATION
DEPENDENT...BUT BY THU MORNING LOOKING AT JUST A DUSTING TO AN
INCH IN THE CHAMPLAIN/CT/ST LAWRENCE VALLEY BUT LOCALLY 2-4" IN
THE NRN ADIRONDACKS AND NRN GREENS. LOWS WEDNESDAY NIGHT MOSTLY
IN THE LOWER 20S...WITH TEENS IN NRN NY. HIGHS THURSDAY WILL BE
BELOW AVG AND GENERALLY 28-32F...WITH MID 20S ACROSS NRN NY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 451 AM EDT MONDAY... FAIRLY GOOD CONGRUENCE EXISTS BETWEEN
00Z GLOBAL MODELS THROUGH THE UPCOMING WEEKEND. CLOSED UPPER LOW
GRADUALLY BEGINS TO LIFT OUT/DE-AMPLIFY THURSDAY NIGHT INTO FRIDAY
WITH UPPER-LEVEL FLOW BECOMING MORE QUASI-ZONAL. A WEAK CLIPPER
MOVES IN LATE FRIDAY NIGHT INTO SATURDAY EXITING THE NORTH
COUNTRY ON SATURDAY NIGHT. SIGNIFICANT DIFFERENCES THEN BEGIN TO
APPEAR SUNDAY NIGHT INTO EARLY NEXT WEEK REGARDING UPPER- LEVEL
ENERGY EJECTION INTO THE CENTRAL AND EASTERN CONUS AND ASSOCIATED
SFC DEVELOPMENT.
UPSLOPE SNOW SHOWERS CONTINUE INTO THURSDAY NIGHT WITH CLEARING
EXPECTED BY FRIDAY. ANY SNOW ACCUMULATION LIMITED TO THE HIGHER
TERRAIN AND LIKELY NOT AMOUNTING TO MUCH MORE THAN A DUSTING TO
2". MDT-STG COLD ADVECTION WITH 925MB TEMPS FALLING TO -8 TO -12C
WITH BELOW NORMAL LOWS FOR THURSDAY NIGHT (UPPER SINGLE DIGITS TO
THE TEENS IN THE WARMER VALLEYS).
WEAK LOW-LEVEL WARM ADVECTION BEGINS AHEAD OF APPROACHING CLIPPER
SYSTEM FOR FRIDAY NIGHT. SLIGHT CHANCE TO CHANCE PRECIPITATION
PROBABILITIES FRIDAY NIGHT BECOMING ALL CHANCE/HIGH CHANCE FOR
SATURDAY...WITH SLIGHTLY HIGHER PROBABILITIES LOCATED ACROSS
SOUTHERN VERMONT. EXPECTING MOSTLY SNOW SHOWERS BUT A RAIN/SNOW
MIX IS EXPECTED IN THE VALLEYS DURING THE AFTERNOON. OROGRAPHIC
SNOW SHOWERS FOR SATURDAY NIGHT. SATURDAY NIGHT ALSO LOOKS TO BE
RATHER COLD FOR MID- MARCH UNDER MDT- STG COLD ADVECTION (925MB
TEMPERATURES FALLING TO -12 TO -14C).
FAIRLY QUIET UNTIL MONDAY WHERE DIFFERENCES BETWEEN 00Z GFS/ECMWF
CLOUDS THE FORECAST. NOTABLY...THE ECMWF SHOWING A STRONGER
SHORTWAVE TROUGH DIGGING INTO THE ROCKIES WITH A SIGNIFICANT
CENTRAL/EASTERN CONUS STORM SYSTEM WHILE THE GFS OFFERS A
WEAKER/LESS PHASED SOLUTION. PREFERENCE IS TOWARD THE MORE
CONSISTENT 00Z ECMWF FOR THIS PERIOD. IF CORRECT...THIS WOULD BE
A FAIRLY MILD SYSTEM WITH POTENTIAL FOR PRECIPITATION TYPE
CHANGES BUT WITH SPECIFIC DETAILS TO EVOLVE IN THE COMING DAYS.
THEREFORE HAVE SLIGHT CHANCE PRECIPITATION PROBABILITIES THROUGH
MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THROUGH 12Z WEDNESDAY...COLD FRONT CONTINUES TO APPROACH FROM THE
WEST WITH MAINLY LIGHT RAIN ALONG/AHEAD OF IT. GUSTS HAVE DROPPED
OFF SOME BUT EXPECT THE GUSTS TO INCREASE AGAIN EARLY THIS
MORNING. LLWS WILL ALSO CONTINUE TO REMAIN A RISK FOR MOST OF THE
TAFS UNTIL FRONTAL PASSAGE. VISIBILITIES IN THE SHOWERS HAVE BEEN
MAINLY 3-6SM AND WOULD EXPECT THIS TO CONTINUE. HIGH RES MODELS
CONTINUE TO SHOW ENHANCEMENT ACROSS CENTRAL/SOUTHERN VT JUST
BEFORE FRONTAL PASSAGE SO WILL NEED TO WATCH POTENTIAL FOR BRIEF
LOWER VISIBILITIES AT RUT AND MPV. FRONTAL PASSAGE EXPECTED
BETWEEN 18-23Z WITH DRIER CONDITIONS EXPECTED EXCEPT FOR SOME
LINGERING RAIN/SNOW SHOWERS AT SLK. WIND SHIFT TO WEST WITH
DROPOFF IN WIND SPEEDS AND GUSTS EXPECTED BEHIND THE FRONT.
THOUGH VISIBILITIES IMPROVE...CEILINGS WILL LIKELY STAY MVFR/VFR
THROUGH THE REST OF THE TAF PERIOD.
OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY...
12Z WEDNESDAY THROUGH 18Z WEDNESDAY...MAINLY MVFR/VFR DUE TO
LOWER CEILINGS AND WITH PERIODS OF RAIN/SNOW SHOWERS AT MPV/SLK.
18Z WEDNESDAY THROUGH 06Z FRIDAY...SCATTERED RAIN/SNOW SHOWERS
DEVELOP ACROSS THE REGION IN NW FLOW ALOFT...MOST PERSISTENT AT
MPV/SLK WITH OROGRAPHIC EFFECTS. PERIODS OF MVFR/IFR POSSIBLE.
06Z FRIDAY THROUGH 06Z SATURDAY...CONDITIONS IMPROVE TO VFR.
06Z SATURDAY ONWARD...LOWERING CEILINGS 06-12Z SATURDAY WITH PERIODS
OF MVFR/IFR POSSIBLE SATURDAY MORNING IN LIGHT RAIN/SNOW
ASSOCIATED WITH CLIPPER SYSTEM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR VTZ007>012-018-019.
NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR NYZ034-035.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS/NEILES
SHORT TERM...BANACOS
LONG TERM...LOCONTO
AVIATION...LOCONTO
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
732 AM EDT TUE MAR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL BRING MODERATE TO BRIEFLY HEAVY RAIN
TODAY AND POSSIBLE MINOR FLOODING ACROSS CENTRAL AND SOUTHERN
VERMONT AND ESSEX COUNTY NEW YORK THIS AFTERNOON THROUGH TONIGHT.
PRECIPITATION ENDS AS A BRIEF PERIOD OF WET SNOW TONIGHT AS THE
COLD FRONT PUSHES EAST THROUGH THE REGION USHERING IN COOLER
TEMPERATURES. TEMPERATURES CLOSER TO SEASONAL LEVELS FOR MID-MARCH
ARE EXPECTED THROUGH THE REMAINDER OF THE WEEK. A LINGERING UPPER
DISTURBANCE WILL BRING SNOW SHOWERS TO THE REGION WEDNESDAY NIGHT
AND THURSDAY RESULTING IN MINOR SNOW ACCUMULATIONS IN THE
VALLEYS...WITH SEVERAL INCHES EXPECTED ACROSS THE NORTHERN ADIRONDACKS
AND NORTHERN GREEN MOUNTAINS.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
AS OF 727 AM EDT TUESDAY...WIDESPREAD RAINFALL EXPECTED TODAY WITH
CONTINUED BREEZY AND MILD TEMPERATURES THIS MORNING (50F AT BTV
AT 11Z)...THEN LESS WIND THIS AFTN. THE NORTH COUNTRY REMAINS IN
PREVAILING DEEP-LAYER SLY FLOW IN ADVANCE OF SLOW- MOVING
OCCLUSION NOW ACROSS W-CENTRAL NY. RUC ANALYSIS SHOWS PW PLUME OF
0.9 TO 1.0" PRECEDING THE FRONT ACROSS NRN NY AND WILL SHIFT SLOWLY
EWD ACROSS VT THIS AFTN. NOTED OVERALL MODEST INCREASE IN QPF PER
00Z GUIDANCE SUITE...ESPECIALLY AS SECONDARY WAVE LOW DEVELOPS
ALONG THE OCCLUSION THIS AFTN AND TRACKS NNEWD ACROSS WRN NEW
ENGLAND THIS AFTN. ADDED MENTION OF HEAVY RAIN ACROSS SRN HALF OF
CWA THIS AFTN BASED ON POSSIBLE 0.5-0.6" RAINFALL IN 6 HR PERIOD.
THIS INCREASE IN RAINFALL AMTS -- COMBINED WITH 3-DAYS OF TEMPS
WELL-ABOVE AVERAGE AND ASSOCIATED SNOW MELT -- HAS WARRANTED
ISSUANCE OF FLOOD WATCH FOR ROUGHLY SRN HALF OF THE CWA. ISSUED
WATCH FOR THOSE COUNTIES WHERE BASIN-AVERAGED STORM TOTAL RAINFALL
IS EXPECTED TO EXCEED 1"...WHICH INCLUDES ESSEX COUNTY NY AND
CENTRAL/S-CENTRAL VT EWD TO CALEDONIA COUNTY AND POINTS SOUTH. RIVER
FLOODING WILL GENERALLY BE IN THE MINOR CATEGORY...BUT WITH ADDED
UNCERTAINTY OF BREAK-UP/MOVING RIVER ICE...THERE COULD BE SOME
LOCALIZED GREATER FLOODING THREAT...ESPECIALLY ON SMALLER STEMS.
HIGH TEMPERATURES WILL GENERALLY OCCUR THIS MORNING WITH TEMPS
AREAWIDE MOSTLY IN THE 40S TO NEAR 50 IN THE CHAMPLAIN VALLEY. SOUTH
WINDS STILL LOCALLY GUSTY ESPECIALLY ACROSS THE HIR TRRN. LOWER
ELEVATION WINDS WILL GRADUALLY SUBSIDE TODAY AS RAINFALL TENDS TO
STABILIZE PBL AND P-GRADIENT FLATTENS THIS AFTN WITH DEVELOPMENT
OF SFC WAVE TO OUR SOUTH.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH THURSDAY/...
AS OF 415 AM EDT TUESDAY...SFC OCCLUSION SHIFTS EWD ACROSS THE REGION
AND LIKELY SHIFTS ACROSS THE CHAMPLAIN VALLEY AROUND 00Z...AND
THEN EAST OF THE CT RIVER BY 06Z. VERTICAL TEMP PROFILE COOLS
ABRUPTLY...AND ANTICIPATE A FEW HOURS OF WET SNOW BEFORE
PRECIPITATION ENDS THIS EVENING UNTIL ABOUT MIDNIGHT CENTRAL VT
AND POINTS WEST...AND PERHAPS HANGING ON IN ERN VT AS LATE AS 09Z.
SHOULD SEE A COATING TO AN INCH MOST LOCATIONS...BUT LOCALLY UP TO
2" ACROSS THE NORTHEAST KINGDOM AS WAVE LOW DEEPENS TO THE EAST
ACROSS NRN NH/ME. OVERNIGHT LOWS GENERALLY IN THE UPR 20S TO LOWER
30S...BUT A FEW COLDER READINGS ARE EXPECTED IN THE NRN
ADIRONDACKS WITH COLDER 850MB TEMPS PUSHING IN FROM THE WEST. A
FEW BREAKS IN THE OVERCAST ARE POSSIBLE BY DAYBREAK ACROSS
S-CENTRAL VT AND THE ST. LAWRENCE VALLEY.
WEDNESDAY WILL GENERALLY BE A MOSTLY CLOUDY DAY BUT NOT ANTICIPATING
MUCH IN THE WAY OF SNOW SHOWER ACTIVITY UNTIL LATE IN THE DAY ACROSS
NRN NY. TRAILING 500MB TROUGH KEEPS MID-LEVEL FLOW S/SW ACROSS THE
REGION UNTIL WEDNESDAY NIGHT...AND AT THAT POINT WE SHOULD SEE AN
INCREASE IN THE OROGRAPHIC SNOW SHOWER ACTIVITY ACROSS THE NRN
ADIRONDACKS AND NRN GREENS. HAVE GENERALLY DRY BUT CLOUDY CONDITIONS
WED WITH HIGHS IN THE UPR 30S TO LOWER 40S. WED NIGHT INTO THU
AM...BETTER POTL FOR SNOW SHOWERS AND HAVE RAISED POPS TO LIKELY
ACROSS THE NRN ADIRONDACKS AND NRN GREENS. SNOWFALL AMTS WILL BE
LARGELY ELEVATION DEPENDENT...BUT BY THU MORNING LOOKING AT JUST A
DUSTING TO AN INCH IN THE CHAMPLAIN/CT/ST LAWRENCE VALLEY BUT
LOCALLY 2-4" IN THE NRN ADIRONDACKS AND NRN GREENS. LOWS WEDNESDAY
NIGHT MOSTLY IN THE LOWER 20S...WITH TEENS IN NRN NY. HIGHS
THURSDAY WILL BE BELOW AVG AND GENERALLY 28-32F...WITH MID 20S
ACROSS NRN NY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 451 AM EDT MONDAY... FAIRLY GOOD CONGRUENCE EXISTS BETWEEN
00Z GLOBAL MODELS THROUGH THE UPCOMING WEEKEND. CLOSED UPPER LOW
GRADUALLY BEGINS TO LIFT OUT/DEAMPLIFY THURSDAY NIGHT INTO FRIDAY
WITH UPPER-LEVEL FLOW BECOMING MORE QUASI-ZONAL. A WEAK CLIPPER
MOVES IN LATE FRIDAY NIGHT INTO SATURDAY EXITING THE NORTH COUNTRY
ON SATURDAY NIGHT. SIGNIFICANT DIFFERENCES THEN BEGIN TO APPEAR
SUNDAY NIGHT INTO EARLY NEXT WEEK REGARDING UPPER- LEVEL ENERGY
EJECTION INTO THE CENTRAL AND EASTERN CONUS AND ASSOCIATED SFC
DEVELOPMENT.
UPSLOPE SNOW SHOWERS CONTINUE INTO THURSDAY NIGHT WITH CLEARING
EXPECTED BY FRIDAY. ANY SNOW ACCUMULATION LIMITED TO THE HIGHER
TERRAIN AND LIKELY NOT AMOUNTING TO MUCH MORE THAN A DUSTING TO 2".
MDT-STG COLD ADVECTION WITH 925MB TEMPS FALLING TO -8 TO -12C WITH
BELOW NORMAL LOWS FOR THURSDAY NIGHT (UPPER SINGLE DIGITS TO THE
TEENS IN THE WARMER VALLEYS).
WEAK LOW-LEVEL WARM ADVECTION BEGINS AHEAD OF APPROACHING CLIPPER
SYSTEM FOR FRIDAY NIGHT. SLIGHT CHANCE TO CHANCE PRECIPITATION
PROBABILITIES FRIDAY NIGHT BECOMING ALL CHANCE/HIGH CHANCE FOR
SATURDAY...WITH SLIGHTLY HIGHER PROBABILITIES LOCATED ACROSS
SOUTHERN VERMONT. EXPECTING MOSTLY SNOW SHOWERS BUT A RAIN/SNOW
MIX IS EXPECTED IN THE VALLEYS DURING THE AFTERNOON. OROGRAPHIC
SNOW SHOWERS FOR SATURDAY NIGHT. SATURDAY NIGHT ALSO LOOKS TO BE
RATHER COLD FOR MID- MARCH UNDER MDT- STG COLD ADVECTION (925MB
TEMPERATURES FALLING TO -12 TO -14C).
FAIRLY QUIET UNTIL MONDAY WHERE DIFFERENCES BETWEEN 00Z GFS/ECMWF
CLOUDS THE FORECAST. NOTABLY...THE ECMWF SHOWING A STRONGER
SHORTWAVE TROUGH DIGGING INTO THE ROCKIES WITH A SIGNIFICANT
CENTRAL/EASTERN CONUS STORM SYSTEM WHILE THE GFS OFFERS A
WEAKER/LESS PHASED SOLUTION. PREFERENCE IS TOWARD THE MORE
CONSISTENT 00Z ECMWF FOR THIS PERIOD. IF CORRECT...THIS WOULD BE A
FAIRLY MILD SYSTEM WITH POTENTIAL FOR PRECIPITATION TYPE CHANGES
BUT WITH SPECIFIC DETAILS TO EVOLVE IN THE COMING DAYS. THEREFORE
HAVE SLIGHT CHANCE PRECIPITATION PROBABILITIES THROUGH MONDAY.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
THROUGH 12Z WEDNESDAY...COLD FRONT CONTINUES TO APPROACH FROM THE
WEST WITH MAINLY LIGHT RAIN ALONG/AHEAD OF IT. GUSTS HAVE DROPPED
OFF SOME BUT EXPECT THE GUSTS TO INCREASE AGAIN EARLY THIS
MORNING. LLWS WILL ALSO CONTINUE TO REMAIN A RISK FOR MOST OF THE
TAFS UNTIL FRONTAL PASSAGE. VISIBILITIES IN THE SHOWERS HAVE BEEN
MAINLY 3-6SM AND WOULD EXPECT THIS TO CONTINUE. HIGH RES MODELS
CONTINUE TO SHOW ENHANCEMENT ACROSS CENTRAL/SOUTHERN VT JUST
BEFORE FRONTAL PASSAGE SO WILL NEED TO WATCH POTENTIAL FOR BRIEF
LOWER VISIBILITIES AT RUT AND MPV. FRONTAL PASSAGE EXPECTED
BETWEEN 18-23Z WITH DRIER CONDITIONS EXPECTED EXCEPT FOR SOME
LINGERING RAIN/SNOW SHOWERS AT SLK. WIND SHIFT TO WEST WITH
DROPOFF IN WIND SPEEDS AND GUSTS EXPECTED BEHIND THE FRONT. THOUGH
VISIBILITIES IMPROVE...CEILINGS WILL LIKELY STAY MVFR/VFR THROUGH
THE REST OF THE TAF PERIOD.
OUTLOOK 12Z WEDNESDAY THROUGH SATURDAY...
12Z WEDNESDAY THROUGH 18Z WEDNESDAY...MAINLY MVFR/VFR DUE TO LOWER
CEILINGS AND WITH PERIODS OF RAIN/SNOW SHOWERS AT MPV/SLK.
18Z WEDNESDAY THROUGH 06Z FRIDAY...SCATTERED RAIN/SNOW SHOWERS DEVELOP
ACROSS THE REGION IN NW FLOW ALOFT...MOST PERSISTENT AT MPV/SLK
WITH OROGRAPHIC EFFECTS. PERIODS OF MVFR/IFR POSSIBLE.
06Z FRIDAY THROUGH 06Z SATURDAY...CONDITIONS IMPROVE TO VFR.
06Z SATURDAY ONWARD...LOWERING CEILINGS 06-12Z SATURDAY WITH PERIODS
OF MVFR/IFR POSSIBLE SATURDAY MORNING IN LIGHT RAIN/SNOW
ASSOCIATED WITH CLIPPER SYSTEM.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR VTZ007>012-018-019.
NY...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH WEDNESDAY
MORNING FOR NYZ034-035.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...LOCONTO
AVIATION...LOCONTO
AREA FORECAST DISCUSSION
NWS BUFFALO NY
112 AM EDT TUE MAR 12 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE INTO QUEBEC TONIGHT...PUSHING A
STRONG COLD FRONT ACROSS THE REGION ALONG WITH A PERIOD OF RAIN
SHOWERS. BEHIND THE FRONT...MUCH COLDER AIR WILL RETURN FOR THE REST
OF THE WEEK WITH PERIODIC LIGHT SNOW SHOWERS...ALTHOUGH HEAVIER LAKE
SNOWS ARE POSSIBLE SOUTHEAST OF THE GREAT LAKES WEDNESDAY NIGHT INTO
THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
COLD FRONT NOW LOCATED FROM NEAR TORONTO THEN SOUTH AND BOWED A BIT
EAST TO BUFFALO THEN BACK SOUTHWEST TO ERIE PA LATE THIS EVENING.
AREA RADARS SHOWING TWO AREAS OF HEAVIER RAIN SHOWERS. ONE IS OUT
AHEAD OF THE COLD FRONT AND IS NOW MOVING ACROSS THE NIAGARA
FRONTIER AND WESTERN SOUTHERN TIER. THE SECOND IS LOCATED BACK
ALONG THE COLD FRONT. IN BETWEEN THESE TWO AREAS JUST LIGHT RAIN
SHOWERS ARE FOUND. THE OTHER CONCERN IS WITH THE GUSTY WINDS AHEAD
OF AND ALONG THE COLD FRONT. AREA SURFACE OBSERVATIONS ACROSS THE
NIAGARA FRONTIER ARE SHOWING GUSTS UP TO 35 MPH WHILE FURTHER SOUTH
IN THE HIGHER TERRAIN OF THE SOUTHERN TIER SOME SITES HAVE REPORTED
UP TO 45 MPH.
WE ARE LOOKING AT A 3 TO 6 HOUR PERIOD OF RAIN... HEAVY AT TIMES
AHEAD OF AND ALONG THE FRONT. MODEL AND WPC CONSENSUS QPF IS IN THE
0.33 TO 0.67 INCH RANGE. FORECAST GRIDS CONTINUE TO SHOW TIMING OF
RAIN SHOWERS ALONG THE LINES OF CURRENT RADAR LOOPS AND RECENT RUNS
OF THE HRRR MODEL WHICH IS HANDLING THE LINE OF SHOWERS WELL.
SHOWERS WILL CONTINUE TO MOVE EAST ACROSS WNY FOR THE NEXT FEW HOURS
WITH THE ENDING TIME FOR SHOWERS RUNNING AROUND 2AM/06Z FOR THE FAR
WEST. THE BEST START TIMING FOR THE GENESEE VALLEY AND FINGER LAKES
REGION WILL BE NEAR MIDNIGHT ENDING AROUND 4AM/08Z. SOME SHOWERS
HAVE REACHED PORTIONS OF THE NORTH COUNTY ALREADY BUT THE STEADIER
RAIN SHOULD HOLD OFF UNTIL AFTER MIDNIGHT AND RUNNING THROUGH THE
EARLY MORNING. THERE IS POTENTIAL FOR SOME LOCALIZED PONDING OR LOW LYING
CONCERNS...BUT SEE NO REAL HYDROLOGIC ISSUES WITH THIS RAIN EVENT.
TEMPERATURES WILL DROP OFF SHARPLY AS MODEST COLD AIR ADVECTION
SETS IN BEHIND THE FRONT. OVERNIGHT READINGS FALLING TO THE UPPER
30S ACROSS THE FAR WEST AND THE LOWER TO MID 40S ELSEWHERE.
MODEST COLD AIR ADVECTION CONTINUING DURING THE DAY TUESDAY WILL
KEEP TEMPERATURES FROM RISING MUCH...WITH MOST HIGHS IN THE LOWER TO
MID 40S...BUT PROBABLY REMAINING IN THE 30S OVER THE HIGHER TERRAIN
OF THE SOUTHERN TIER. LOW LEVEL RIDGING AND MID LEVEL DRYING WILL
LIKELY KEEP ANY PRECIPITATION LIMITED DURING TUESDAY WITH THE BEST
CHANCES FOR ANY DEVELOPMENT IN FAVORED UPSLOPE AREAS. ANY
PRECIPITATION THAT DOES MANAGE TO DEVELOP WILL LIKELY BE IN THE FORM
OF A RAIN/SNOW MIX FOR MUCH OF THE DAY...BUT LIKELY TRANSITIONING
OVER TO ALL SNOW BY THE END OF THE DAY AS THE COLD AIR CONTINUED TO
DEEPEN...ESPECIALLY ACROSS THE SOUTHERN TIER.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
TEMPERATURES WILL CONTINUE A SHARP DOWNWARD TREND TUESDAY NIGHT IN
THE WAKE OF THE AFOREMENTIONED COLD FRONT...WHICH SHOULD JUST BE
EXITING THE NORTH COUNTRY THURSDAY EVENING. EXPECT TEMPERATURES TO
FALL BELOW THE FREEZING MARK OVERNIGHT AS SUBSTANTIALLY COLDER AIR
FILTERS ACROSS THE LOWER GREAT LAKES IN ASSOCIATION WITH A DEEP
LONGWAVE TROUGH DROPPING ACROSS THE REGION. AS THIS LONGWAVE TROUGH
SHIFTS OVERHEAD THE LOWER GREAT LAKES EXPECT SCATTERED SNOW SHOWERS
TO DEVELOP ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY.
AS EVEN COLDER AIR PUSHES ACROSS THE REGION LATER IN THE DAY ON
WEDNESDAY AND 850 MB TEMPS DROP BELOW -10C...LOOK FOR SHOWER
ACTIVITY TO PICK UP WITH THE DEVELOPMENT OF LAKE EFFECT SNOW SHOWERS
DOWNWIND OF THE LAKES WEDNESDAY THROUGH THURSDAY MORNING. GIVEN THAT
THE FLOW WILL BE WEST-NORTHWESTERLY WITH EQUILIBRIUM LEVELS QUICKLY
FALLING FROM AROUND 8KFT TO 5KFT...DO NOT EXPECT ACCUMULATIONS TO
RUN MORE THAN A COUPLE OF INCHES OFF OF LAKE ERIE WITH SNOWS
ACCUMULATING MAINLY SOUTH OF BUFFALO. HOWEVER...ACCUMULATIONS
SOUTHEAST OF LAKE ONTARIO MAY APPROACH ADVISORY LEVELS WEDNESDAY
NIGHT INTO THURSDAY GIVEN LONGER FETCH OF THE LAKE ALONG WITH THE
PRESENCE OF COLDER ALOFT WITH 850MB TEMPS RUNNING IN THE
NEIGHBORHOOD OF -15C TO -18C. THE PERIOD OF SNOW SHOWERS WILL BE
REALTIVELY SHORT-LIVED HOWEVER AS THE UPPER LEVEL TROUGH TRANSITS
THE REGION AND SHORTWAVE RIDGING MOVES INTO THE REGION...BRINGING AN
END TO THE BULK OF ANY ACTIVITY.
THE SIGNIFICANTLY COLDER AIRMASS ASSOCIATED WITH THE UPPER LEVEL
TROUGH WILL BE REFLECTED IN THE SURFACE TEMPERATURES AS WELL AS
HIGHS IN THE LOW TO MID 30S WEDNESDAY GIVE WAY TO READINGS THAT
SHOULD ONLY TOP OUT IN THE 20S THURSDAY. ABUNDANT CLOUD COVER
COUPLED WITH THE LONGER DAYS SHUOLD HELP LIMIT THE TEMPERATURE DROP
OVERNIGHT...SUGGESTING LOWS IN THE UPPER TEENS INLAND WITH LOW TO
MID 20S NEAR THE LAKES BOTH WEDNESDAY AND THURSDAY NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
FRIDAY WILL START OUT QUIET AND DRY ACROSS MOST AREAS AS SHORTWAVE
RIDGING MOVES ACROSS THE LOWER GREAT LAKES. THE MAIN CHANCE OF
PRECIPITATION THIS WEEKEND WILL BE ASSOCIATED WITH A FAST-MOVING
CLIPPER DROPS ACROSS THE GREAT LAKES. MODELS ARE IN GOOD AGREEMENT
ON THIS SYSTEM CROSSING THE AREA SOMETIME FRIDAY NIGHT OR SATURDAY
AND WARM ADVECTION AHEAD OF THE SURFACE SLOW WILL LIKELY BRING A
BRIEF MODERATION IN TEMPERATURES ALONG WITH A WIDESPREAD INCH OR TWO
OF WET SNOW. THERE ARE ISSUES IN THE EXACT TIMING OF THIS SYSTEM AND
AS A RESULT HAVE OPTED TO JUST STICK WITH A CHANCE OF SNOW UNTIL
TIMING FIRMS UP.
THE SECOND HALF OF THE WEEKEND SHUOLD BE DRY AS HIGH PRESSURE BUILDS
ACROSS THE REGION IN THE WAKE OF THE CLIPPER...HOWEVER LOOK FOR
TEMPERATURES TO REMAIN BELOW NORMAL AS THE HIGH WILL BE ACCOMPANIED
BY PLENTY OF COLD AIR.
&&
.AVIATION /05Z TUESDAY THROUGH SATURDAY/...
AS OF 05Z...THE SURFACE COLD FRONTAL BOUNDARY AND AXIS OF AN
ASSOCIATED BAND OF SHOWERS WAS DRAPED FROM KROC TO KBFD. THE FRONT
AND BAND OF SHOWERS WILL CONTINUE TO PRESS EASTWARD THROUGH THE
REMAINDER OF THE OVERNIGHT HOURS...WITH ANY LINGERING LLWS
ENDING...SURFACE WINDS SHIFTING TO WEST-SOUTHWESTERLY...AND CIGS
FALLING TO MVFR/LOCALIZED IFR WITH ITS PASSAGE. IMMEDIATELY BEHIND
THE FRONT...SOME SHOWERS WILL LINGER FOR A FEW HOURS FOLLOWING THE
FROPA...THEN MAINLY DRY WEATHER IS EXPECTED FOR THE BALANCE OF THE
PERIOD WITH CIGS IMPROVING BACK TO LOWER-END VFR FROM WEST TO EAST
DURING THE COURSE OF TUESDAY. THIS SAID...WINDS WILL REMAIN FAIRLY
BRISK OUT OF THE WEST-SOUTHWEST DOWNWIND OF LAKE ERIE...WHERE GUSTS
TO 25-30 KTS WILL BE LIKELY FOR MOST OF THE DAY.
OUTLOOK...
WEDNESDAY...MVFR WITH SNOW SHOWERS LIKELY.
THURSDAY...VFR/MVFR WITH SCATTERED SNOW SHOWERS.
FRIDAY AND SATURDAY...VFR.
&&
.MARINE...
LOW PRESSURE WILL LIFT FROM THE CENTRAL GREAT LAKES INTO WESTERN
QUEBEC...WITH ITS TRAILING COLD FRONT CROSSING THE REGION OVERNIGHT.
IN THE WAKE OF THIS FRONT...A WESTERLY FLOW OF MUCH COLDER AIR
WILL OVERSPREAD THE LOWER LAKES...WITH THE COMBINATION OF THE COLD
AIR ADVECTION AND A TIGHTENING PRESSURE GRADIENT LIKELY BRINGING AN
EXTENDED PERIOD OF ADVISORY LEVEL WINDS AND WAVES FROM TUESDAY
THROUGH THURSDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 6 PM EDT
WEDNESDAY FOR LEZ040-041.
&&
$$
SYNOPSIS...TMA
NEAR TERM...SMITH/TMA
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...JJR/SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
726 PM CDT WED MAR 13 2013
.DISCUSSION...REPORTS OF FREEZING RAIN COMING FROM CANADA...AND
RUGBY ALSO REPORTING -RA. WILL NEED TO ISSUE A FREEZING RAIN
ADVISORY FOR THE DEVILS LAKE BASIN THROUGH THE EVENING HOURS. NOT
QUITE SURE HOW THIS SYSTEM WILL EVOLVE OVER THE NEXT FEW
HOURS...WITH THE MAIN QUESTIONS BEING SOUTHERN EXTENT OF PRECIP
AND THE EASTERN EXTENT OF FZRA (WHEN IT BECOMES SNOW). FOLLOWING
THE 23Z RAP 850MB TEMPS...THE CURRENT ADVISORY AREA MAY NEED TO BE
EXPANDED A TIER OF COUNTIES EAST...BUT SHOULD BE ALL SNOW EAST OF
THE VALLEY. WILL MONITOR AND UPDATE AS NEEDED.
&&
.AVIATION...
FREEZING RAIN A STRONG POSSIBILITY FROM THE VALLEY WEST. EXPECT A
BRIEF PERIOD OF MVFR CIGS ALONG WITH PRECIP...THEN MORE WIDESPREAD
LOW CIGS THUR MORNING.
&&
.PREV DISCUSSION... /ISSUED 323 PM CDT WED MAR 13 2013/
SHORT TERM...TONIGHT THROUGH FRIDAY
CHALLENGES INCLUDE MIXED PRECIPITATION TONIGHT AND THEN THE NEXT
ROUND OF SNOW THURSDAY NIGHT THROUGH FRIDAY. GFS/NAM/ECMWF/GEM ARE
IN GOOD OVERALL AGREEMENT AND WILL USE A BLENDED SOLUTION.
20 UTC WATER VAPOR LOOP SHOWS A SHORT-WAVE ROUNDING THE TOP OF THE
500 HPA INTER-MOUNTAIN RIDGE AND MOVING ACROSS SOUTHWEST SASKATCHEWAN
INTO NORTHEAST MT. THIS WAVE WILL MOVE ACROSS THE FORECAST AREA
TONIGHT IN NORTHWEST FLOW ALOFT...BRINGING WITH IT A SNOW/FREEZING
RAIN MIX. REGIONAL RADARS CURRENTLY SHOWING VERY FEW ECHOES ACROSS
THE ENTIRE REGION...WHICH IS LIKELY A REFLECTION OF VERY DRY AIR
ABOVE THE BOUNDARY LAYER. IT WILL TAKE SOME TIME TO OVERCOME THIS
DRY AIR AND SATURATE...BUT MODELS SUGGEST 2 TO 4 G/KG MIXING RATIOS
WILL ADVECT INTO THE AREA COINCIDENT WITH STRONG MID-LEVEL WARM
AIR ADVECTION...ISENTROPIC LIFT ON THE 280 TO 290 K SURFACE AND
UPPER LEVEL SUPPORT FROM THE LEFT EXIT REGION OF A 100+ KT 300 HPA
JET.
MID-LEVEL THERMAL ADVECTION WILL RESULT IN A 800 TO 850 HPA WARM
LAYER FROM +2 TO +5 C MOVING ACROSS THE FORECAST AREA FROM WEST TO
EAST. SURFACE TEMPERATURES IN THE 20S WILL ALLOW ANY RAIN THAT FALLS
TO FREEZE ON CONTACT. BASED ON THIS THERMAL PROFILE...SREF PROBABILITY
OF P-TYPE SHOWS THE BEST CHANCE FOR FREEZING RAIN ALONG AND SOUTHWEST
OF A LINE FROM CANDO TO GRAND FORKS TO WADENA. FARTHER NORTH AND
EAST...TEMPERATURES SHOULD REMAIN COLD ENOUGH FOR ALL SNOW. TOTAL
SNOW ACCUMULATIONS SHOULD GENERALLY BE AN INCH OR LESS...ALTHOUGH
UP TO 2 INCHES ARE POSSIBLE ACROSS PORTIONS OF NORTHWEST AND WEST
CENTRAL MN. OTHERWISE...FREEZING RAIN/ICE ACCUMULATIONS OF A FEW
HUNDREDTHS ARE POSSIBLE MAINLY ACROSS EASTERN ND. EVEN A THIN
GLAZE WILL RESULT IN VERY SLICK CONDITIONS...MAKING TRAVEL TONIGHT
VERY DIFFICULT IN PLACES.
CONTEMPLATED ISSUING A WINTER WEATHER ADVISORY FOR A SNOW/FREEZING
RAIN MIX...BUT CONFIDENCE NOT HIGH ENOUGH IN EXACT PLACEMENT OR
AMOUNTS...ESPECIALLY GIVEN LACK OF CURRENT RADAR ECHOES. MOST
PRECIPITATION SHOULD HOLD OFF UNTIL 03 UTC AND THIS WILL GIVE THE
EVENING SHIFT ENOUGH TIME TO EVALUATE THE LATEST CONDITIONS AND
ISSUE AN ADVISORY IF NECESSARY.
THURSDAY WILL BE MOSTLY DRY WITH CLOUD COVER SLOWLY DECREASING
FROM WEST TO EAST AS HIGH PRESSURE NOSES INTO THE NORTHERN PLAINS.
IT WILL BE THE WARMEST DAY OF THE WEEK WITH HIGH TEMPERATURES AT
OR ABOVE FREEZING.
ATTENTION THEN TURNS TO THURSDAY NIGHT THROUGH FRIDAY AS COLD
CANADIAN AIR MASS OOZES SOUTHWARD FROM POLAR VORTEX...TIGHTENING THE
MID-LEVEL THERMAL GRADIENT ACROSS THE FORECAST AREA. ALL MODELS
DEVELOP A BAND OF LIGHT SNOW ALONG THIS GRADIENT. A MIX OF
FREEZING RAIN IS STILL POSSIBLE ACROSS THE SOUTH BEFORE COLDER AIR
ADVECTS INTO THE REGION...BUT LOOK FOR TOTAL SNOW ACCUMULATIONS OF
2 TO 4 INCHES ACROSS MOST OF THE FORECAST AREA. THE HIGHEST TOTALS
APPROACHING 5 TO 6 INCHES SHOULD BE ALONG A LINE FROM NEW ROCKFORD
TO MAYVILLE TO WADENA...WHICH IS SLIGHTLY FARTHER SOUTH THAN THE
PREVIOUS FORECAST. NOT A LOT OF WIND WITH THIS SYSTEM...BUT SOME
BLOWING AND DRIFTING WILL BE POSSIBLE ON FRIDAY AFTER WINDS SHIFT
TO THE NORTH FROM 10 TO 20 MPH AND GUSTS TO 25 MPH.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY
FOCUS FOR LONG TERM FORECAST WILL BE YET ANOTHER HYBRID SYSTEM
COMING OUT OF THE PAC NW. MODELS STILL IN GENERAL AGREEMENT WITH THE
SOUTHERN RRV HAVING THE BEST CHANCE FOR SNOWFALL...HOWEVER THE GFS
MOVES THE UPPER WAVE THROUGH FASTER. NEW ECMWF HAS SHIFTED FROM A
CLOSED UPPER LOW TO AN UPPER WAVE (AND ALSO A TAD FURTHER NORTH)...
WHICH THE GFS HAS SHOWN THE LAST TWO RUNS. ALLBLEND SOLUTION YIELDED
BORDERLINE LIKELIES FOR SOUTHERN VALLEY...SO IN COORDINATION WITH
NEIGHBORS DID INCREASE POPS ACROSS THE SOUTH. AMPLE MOISTURE EXPECTED
WITH THIS SYSTEM AND WILL LIKELY PROLONG THE SNOWPACK SEASON AND
FURTHER DELAY THE SPRING MELT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FREEZING RAIN ADVISORY UNTIL 1 AM CDT THURSDAY FOR NDZ006-007-
014-015-024-026-054.
MN...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
345 PM CDT TUE MAR 12 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 342 PM CDT TUE MAR 12 2013
TEMPERATURES AND TRENDS TONIGHT WILL BE VERY DEPENDENT ON A
DIFFICULT CLOUD FORECAST. A LARGE PART OF CURRENT CLOUD COVERAGE IS
DIURNALLY SUPPORTED AS BREAKS HAVE FILLED BACK IN DURING THE
DAY...WITH SCATTERED COVERAGE OF VERY LIGHT SNOW OR FLURRIES OVER
MUCH OF THE CWA. RAP SOMEWHAT A JECKYLL AND HYDE OF LATE WHEN IT
COMES TO LOWER CLOUD PREDICTION...BUT GENERALLY SEEMS ON TRACK WITH
CURRENT CLOUDS. HAS A MUCH SLOWER CLEARING RATE FROM WEST TO
EAST...BUT PROBABLY TOO MUCH SO WITH THE DEGREE OF DIURNALLY DRIVEN
CLOUDS WHICH WILL ERODE QUICKLY WEST...AND TO SOME DEGREE IN THE FAR
EAST AS WELL...LEAVING A MORE PERSISTENT BAND DOWN THE MIDDLE TO
DISSIPATE MORE SLOWLY AND BUILD EAST. COMPLICATING TRENDS WILL BE
THE SLOW EASTWARD SHIFT IN SURFACE RIDGE...BRINGING LIGHT RETURN
FLOW TO AREAS FROM THE JAMES VALLEY WEST LATER NIGHT...ALONG WITH
INCREASING HIGH LEVEL CLOUDS.
COULD BE A FEW LOCATIONS OF BLOWING SNOW THROUGH LATE AFTERNOON IN
DEEPER SNOW AREAS NORTH AND EAST...BUT OVERALL TREND IN WINDS GOING
INTO THE EVENING WILL BE DOWN...AND EXPECT WILL NOT CONTINUE INTO
THE EVENING. MUCH OF CURRENT PRECIPITATION RESULT OF THE STEEP LOW
LEVEL LAPSE RATES...AND WILL PROBABLY TAKE A COUPLE OF HOURS INTO
THE EVENING BEFORE FULLY LOSING A FLURRY THREAT WITH TEMPS IN CLOUD
LAYER SUPPORTIVE OF ICE PROCESS.
ON WEDNESDAY...DECENT COVERAGE OF MID/HIGH CLOUDS WILL PUSH EASTWARD
ACROSS THE AREA. WEAKER LOW LEVEL GRADIENT AND SNOWCOVER EAST WILL
RESTRAIN TEMPERATURES TO THE LOWER PORTIONS OF GUIDANCE RANGE WITH
UPPER 20S. MUCH WARMER AIRMASS PUSHES INTO THE WEST...SHOULD ALLOW
SOME LOWER 40S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 342 PM CDT TUE MAR 12 2013
BOTH THURSDAY AND FRIDAY PLACE THE CWA RIGHT ALONG A STRONG THERMAL
GRADIENT IN THE LOW LEVELS WHICH MAKES FORECASTING HIGHS TRICKY. NOT
JUST SIMPLY DUE TO THE STRONG THERMAL GRADIENT BUT IF THURSDAY DOES
NOT PROVIDE ENOUGH SOLAR RADIATION THE SNOW MAY NOT MELT AS MUCH AS
EXPECTED WHICH COULD INFLUENCE HIGHS ON THURSDAY. WILL PLAN ON SOME
MELTING TO OCCUR WEDNESDAY IN CENTRAL SOUTH DAKOTA WHICH WILL ALLOW
TEMPERATURES TO CLIMB A BIT SOUTH OF INTERSTATE 90 WHERE MUCH OF
THAT AREA IS ALREADY SNOW FREE...ON THE SOUTH DAKOTA SIDE OF THINGS.
SO WILL GO CLOSE TO 60 IN THESE LOCATIONS TAPERING OFF TO NEAR 40 IN
SOUTHWEST MINNESOTA. BUT AGAIN...WITH THE TIGHT THERMAL GRADIENT
CONFIDENCE IS NOT EXTREMELY HIGH. THIS THERMAL GRADIENT SHIFTS A BIT
NORTHWARD ON THURSDAY NIGHT INTO FRIDAY BEFORE SLIDING BACK
SOUTHWARD AS A WAVE MOVES THROUGH NORTH DAKOTA WHICH WILL PUSH THIS
COLDER AIR SOUTH. WILL KEEP TEMPERATURES MILD THURSDAY NIGHT...WITH
LOWS IN UPPER 20S TO LOWER 30S. WILL RULE OUT THE GFS AND LEAN
TOWARDS THE EC AND NAM OUTPUT ON FRIDAY. THE GFS DOES NOT SEEM TO
HANDLE LOW LEVEL FEATURES OF SYSTEMS TO THE NORTH VERY WELL AS IT
TENDS TO COLLAPSE THE COLD AIR INTO THE PRE FRONTAL TROUGH WHILE THE
EC AND NAM TEND TO HANDLE THIS BETTER. WHAT THIS MEANS IS THAT
FRIDAY SHOULD BE VERY MILD ...ESPECIALLY DOWN THE MISSOURI RIVER
WHICH WILL AGAIN SEE TEMPERATURES CLIMB TO AROUND 60 WHILE 40 TO 45
SHOULD BE MORE COMMON IN THE NORTH. IN FACT IF THINGS ARE AS SLOW AS
THE NAM SUGGESTS IT COULD CLIMB INTO THE LOWER 50S ALONG THE HIGHWAY
14 CORRIDOR.
SATURDAY AND SUNDAY WILL SEE FAIRLY STRONG WEST/NORTHWEST FLOW ALOFT
AHEAD OF A MARGINALLY AGREED UPON FORECAST TROUGH OF LOW PRESSURE
FOR SUNDAY NIGHT INTO MONDAY NIGHT. WITH COLD AIR IN PLACE ON
SATURDAY MORNING WEAK EAST TO SOUTHEAST FLOW WILL TRY TO RETURN
CONDITIONS BACK TO NORMAL BUT COLDER AIR WILL BEGIN TO SINK SOUTH
SUNDAY AHEAD OF THE TROUGH OF LOW PRESSURE. OVERALL EACH OF THE
MODELS IS COLD ENOUGH THAT ANY PRECIPITATION THAT FALLS WOULD BE
SNOW WITH AN EAST TO SOUTHEAST LOW LEVEL FLOW ADVECTING IN THE
COOLER AND DRIER AIR TO THE EAST. COLDER AIR BURIES IN BEHIND THIS
WAVE TUESDAY INTO WEDNESDAY BUT AGAIN...SOME DECENT TIMING
DIFFERENCES SO CONFIDENCE IS AVERAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1252 PM CDT TUE MAR 12 2013
MVFR CEILINGS THROUGH THE AFTERNOON FOR SITES...REDEVELOPING A
SLIGHTLY LOWER STRATOCUMULUS LAYER WITH SURFACE BASED HEATING.
SHOULD SEE A FAIRLY RAPID WEST TO EAST DISSIPATION OF CEILINGS
INTO JAMES VALLEY...AND SLOWING A BIT HEADING EAST. CARRIED LESS
TEMPORAL MENTION THROUGH THE AFTERNOON FOR SPOTTY MVFR
VISIBILITIES IN SNOW SHOWERS AT TAF SITES...WITH INCREASINGLY
SCATTERED NATURE OF SNOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHAPMAN
LONG TERM...08
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
904 PM CDT WED MAR 13 2013
.SHORT TERM...TONIGHT INTO TOMORROW MORNING
904 PM CDT WED MAR 13 2013
THE MAIN SHORT TERM FOCUS IS ON THE SNOW POTENTIAL OVERNIGHT INTO
TOMORROW MORNING. THIS SYSTEM IS CURRENTLY IN EASTERN NORTH DAKOTA
WHERE A BAND OF SNOW IS SHOWING UP ON RADAR. HOWEVER...SOME OF
THIS SNOW IS NOT MAKING IT DOWN TO THE GROUND DUE TO A DRY LAYER
OBSERVED BETWEEN 900-700MB ON MPX/INL/ABR 14.00Z SOUNDINGS. THE
13.23Z AND PREVIOUS RUNS OF THE HRRR SEEM TO HAVE A GOOD HANDLE ON
THIS BAND OF SNOW AS IT DROPS DOWN INTO THE REGION OVERNIGHT WITH
IT BECOMING ALIGNED ALONG THE MISSISSIPPI RIVER BY 12Z TOMORROW
MORNING ALL THE WAY DOWN INTO NORTHEAST IOWA. MID LEVEL FORCING IS
RATHER WEAK AS THE MID LEVEL TROUGH IS NOT VERY DEEP. SO...MUCH
OF THE FORCING IS FROM LOW LEVEL WARM AIR ADVECTION AND ISENTROPIC
LIFT ON THE 285K SURFACE. THIS LIFT QUICKLY DROPS TO THE SOUTHEAST
TOMORROW MORNING...LEAVING THE REGION WITH A 3-5 HOUR CLIP FOR
THIS SNOW. CONSIDERED DROPPING DOWN THE 1-2 INCH SNOW BAND IN THE
FORECAST DOWN TO JUST AROUND AN INCH BECAUSE OF THE DRY WEDGE IN
PLACE...BUT THE POTENTIAL FOR SOME BANDING COULD LEAD TO SOME
LOCALLY HIGHER AMOUNTS THAT PERHAPS APPROACH TWO INCHES.
OVERALL...EXPECT THAT MOST OF THE AREA WILL JUST SEE A DUSTING TO UP TO
AN INCH OF SNOW FROM THIS BEFORE IT ENDS BY NOON TOMORROW MORNING.
AS FAR AS THE FREEZING DRIZZLE IS CONCERNED...THE ISENTROPIC LIFT
WEAKENS RATHER QUICKLY AND AM NOT VERY CONFIDENT THAT THERE WILL
BE ANY SORT OF LIFT LEFT AS THE COLUMN LOSES ICE THROUGH THE
MORNING. DUE TO THIS...WILL BE REMOVING THIS FROM THE FORECAST FOR
TOMORROW MORNING.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
316 PM CDT WED MAR 13 2013
13.00Z/13.12Z MEDIUM RANGE MODELS IN MODEST AGREEMENT SUN THRU MON
AS A STRONGER SHORTWAVE TROUGH DIGS THRU THE NORTHERN ROCKIES SUN
THEN INTO THE UPPER MIDWEST BY MON. OVERALL TREND IS A BIT SLOWER/
STRONGER...WITH MODELS FLIP-FLOPPING A BIT ON TIMING/STRENGTH.
MODEST BETWEEN MODEL AGREEMENT CONTINUES MON NIGHT-WED AS THIS
TROUGH MOVES EAST AND THRU THE EASTERN CONUS AND FLAT RIDGING MOVES
ACROSS CENTRAL NOAM. HOWEVER MORE BETWEEN MODEL TIMING DIFFERENCES
BY WED...FASTER GFS VS. SLOWER ECMWF WITH THE NEXT ENERGY COMING
THRU THE FLOW...START TO HAVE A BIG IMPACT ON THE POTENTIAL SENSIBLE
WEATHER FOR DAY 7. FCST CONFIDENCE AVERAGE SUN-TUE THEN ON THE LOW
SIDE WED. CAN HIGH PRESSURE REMAINS OVER THE UPPER MIDWEST SUN FOR
WHAT SHOULD BE A QUIET WEATHER DAY WITH CONTINUED BELOW NORMAL
TEMPS. BY SUN NIGHT AND FOR MON/MON NIGHT THE NEXT STRONGER
TROUGH...SFC LOW AND ROUND OF DEEP LAYERED FORCING/LIFT SPREAD
ACROSS THE REGION. CONSISTENT SIGNAL FOR THE AREA TO RECEIVE PRECIP
CENTERED ON MON. MODEL CONSENSUS PRECIP CHANCES INCREASING SUN
NIGHT...60-70 PERCENT MON AND DECREASING MON NIGHT LOOK GOOD UNTIL
THE TIMING/STRENGTH DETAILS BECOME CLEARER. FAVORING THE MODEL
CONSENSUS...APPEARS BULK OF THE PRECIP WITH THIS SYSTEM WOULD FALL
AS SNOW BUT AMOUNTS REMAIN IN QUESTION. DRY/COOL CAN HIGH PRESSURE
SETTLES ACROSS THE REGION FOR TUE. BY WED...FASTER GFS SPREADS THE
NEXT ROUND OF FORCING/LIFT AND WINTRY PRECIP INTO THE AREA WHILE
SLOWER ECMWF HOLDS THE AREA DRY UNDER THE CAN HIGH PRESSURE. WITH
LITTLE FCST CONFIDENCE BY WED...SMALL CONSENSUS PRECIP CHANCE WED OK
FOR NOW. GIVEN CAN HIGH PRESSURE OR WINTRY PRECIP PRODUCING SYSTEMS
IMPACTING THE REGION...MODEL CONSENSUS TEMPS A CATEGORY OR TWO BELOW
NORMAL LOOK WELL TRENDED FOR DAYS 4-7.
&&
.AVIATION...TONIGHT AND THURSDAY
639 PM CDT WED MAR 13 2013
THE MAIN FOCUS WITH THE TAFS IS WITH THE SNOW MOVING IN LATE
OVERNIGHT INTO TOMORROW MORNING. IFR CONDITIONS ARE EXPECTED TO
DEVELOP AS THE LIGHT SNOW MOVES IN AROUND 10Z AT RST AND 12Z AT
LSE AS THE NEXT SYSTEM MOVES INTO THE REGION. HIGH LEVEL CLOUD
COVER IS ALREADY SPREADING IN FROM THE NORTHWEST IN ADVANCE OF
THIS SYSTEM...BUT CONDITIONS WILL STAY VFR UNTIL THE SNOW BEGINS
TO FALL TOMORROW MORNING. VISIBILITY SHOULD DROP TO AROUND 2SM OR
LESS AT TIMES WITH THE SNOW WITH RST MORE LIKELY TO SEE IFR
CEILINGS OCCUR AS WELL.
THE 13.22Z RAP AND 13.18Z NAM/GFS ARE HINTING THAT THE LOW LAYERS
DRY OUT FAIRLY QUICKLY AS THE LIFT SHIFTS TO THE EAST WITH IFR
CONDITIONS SCATTERING OUT BEFORE 18Z. WITH THIS WEAKENING LIFT AND
LOWER RH...AM NOT AS CONFIDENT IN THE FREEZING DRIZZLE
OCCURRING...SO HAVE PULLED THAT MENTION WITH THESE TAFS. WINDS
WILL START OUT OF THE WEST THIS EVENING BEFORE SHIFTING AROUND TO
THE SOUTHEAST LATER TONIGHT BUT MAINLY STAYING ON THE LIGHT SIDE
WITH SOME 10-12KT SUSTAINED WINDS EXPECTED FOR A BRIEF PERIOD
TOMORROW MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 PM CDT WED MAR 13 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....RRS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
639 PM CDT WED MAR 13 2013
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
316 PM CDT WED MAR 13 2013
MAIN FORECAST CONCERNS THIS PACKAGE...SNOW/MIXED PRECIP CHANCES
CENTERED ON THU MORNING AND AGAIN ON FRI...TEMPERATURES THRU THE
PERIOD.
18Z DATA ANALYSIS HAD A BROAD RIDGE OF HIGH PRESSURE FROM EASTERN
MAN/WESTERN ONT THRU MN TO KS/MO. WV IMAGERY SHOWING DRY NORTHWEST
FLOW ALOFT OVER MN/IA/WI. VIS IMAGERY AND SFC OBS INDICATED
GENERALLY CLEAR SKIES ACROSS THE UPPER MIDWEST AT MID-DAY. EVEN WITH
THE CLEAR/SUNNY SKIES...TEMPERATURES WERE ON THE COOL SIDE FOR A
MID MARCH DAY. MOST MID-DAY TEMPS WERE IN THE 20S TO AROUND 30 OVER
THE SNOW COVER AND WITH SOME LIGHT NORTHWEST WIND FLOW.
13.12Z MODEL RUNS LOOK TO HAVE INITIALIZED WELL AND OFFER AS SIMILAR
OF SOLUTIONS AS CAN BE EXPECTED FOR TONIGHT INTO SAT NIGHT...WITH
MULTIPLE SHORTWAVES IN NORTHWEST FLOW TO IMPACT THE AREA. SOME LOWER
LEVEL TEMPERATURE DIFFERENCES WHICH WOULD IMPACT PRECIP TYPES ON FRI
BUT AGAIN THIS NOT COMPLETELY UNEXPECTED. DPROG/DT OF 500MB HGTS AT
13.12Z SHOWED THE MODEL RUNS OF 11.12Z AND 12.12Z VERIFIED QUITE
WELL ACROSS NOAM/EASTERN PAC...WITH BETTER RUN-TO-RUN CONSISTENCY TO
GFS. MODELS CONVERGING ON A TIGHTER CONSENSUS TOWARD THE STRONGER OF
EARLIER RUNS AS A SHORTWAVE TO DROP ACROSS THE REGION THU. TREND
GENERALLY FAVORS STRONGER OF EARLIER RUNS WITH A TIGHTER CONSENSUS
ON THE SHORTWAVE TO DROP ACROSS THE UPPER MIDWEST FRI/FRI NIGHT. BY
SAT/SAT NIGHT PLENTY OF BETWEEN MODEL AND RUN-TO-RUN DETAIL
DIFFERENCES WITH BROAD TROUGHING OVER THE REGION AND WITH THE NEXT
STRONGER TROUGH/ENERGY APPROACHING THE WEST COAST. ECMWF WITH
SOMEWHAT BETTER RUN-TO-RUN CONSISTENCY THRU FRI NIGHT...THEN NO
MODEL CLEARLY BETTER BY SAT NIGHT. CHECK OF OBS VS. MODEL DATA AT
18Z SHOWED MODELS ALL REASONABLE WITH THE SFC MASS FIELDS ACROSS
THE CENTRAL CONUS. PER WV IMAGERY MODELS ALL LOOK GOOD WITH THE
OVERALL SHORTWAVE PICTURE ACROSS NOAM/EASTERN PAC...BUT LOOK TO BE
STRUGGLING A BIT WITH THE WEAKER SHORTWAVE CROSSING THE ROCKIES
JUST NORTH OF THE US/CAN BORDER /THE WAVE OF INTEREST FOR THU/.
NO CLEAR MODEL FAVORITE THIS CYCLE. WITH GFS/ECMWF SHOWING SOME OF
THE BETTER RUN-TO-RUN CONSISTENCY...FAVORED A MODEL BLEND WEIGHTED
TOWARD THESE 2 THIS CYCLE. SHORT TERM FCST CONFIDENCE GOOD THRU FRI
NIGHT...THEN AVERAGE SAT/SAT NIGHT.
IN THE SHORT TERM...LOWER LEVEL THERMODYNAMIC FORCING/LIFT AND 925-
500MB MOISTURE...AHEAD OF THE SHORTWAVE CROSSING THE CAN ROCKIES...
SPREADS QUICKLY SOUTHEAST AND INTO THE AREA TONIGHT. MOISTURE/CLOUDS
CAN BE SEEN INCREASING OVER THE DAKOTAS AND SOUTH-CENTRAL CAN EARLY
THIS AFTERNOON. BY LATE TONIGHT...GOOD MODEL CONSENSUS FOR THE
THE MOISTURE/LIFT TO BE DEEP/STRONG ENOUGH TO SPREAD SOME -SN INTO
THE NORTHWEST HALF OF THE FCST AREA. INCREASED SNOW CHANCES OVER
THE NORTHWEST END OF THE FCST AREA INTO THE 60-90 PERCENT RANGE BY
11-12Z THU...THEN SPREAD THESE SNOW CHANCES SOUTHEAST ACROSS THE
FCST AREA THU MORNING. IN THE 09Z-15Z PERIOD...MODEL SOUNDINGS
SHOWING MOISTURE COLUMN DEEP/COLD ENOUGH FOR ICE IN THE CLOUDS.
HOWEVER...925-850MB WARMING SPREADS EAST ACROSS THE FCST AREA THRU
THE MORNING WHILE THE COLUMN ABOVE ABOUT 800MB DRIES OUT...WITH A
RATHER RAPID LOSS OF ICE IN THE CLOUDS AFTER ABOUT 16Z. EXPANDED THE
CHANCES OF MIXED PRECIP/-FZDZ EAST ACROSS THE FCST AREA THRU THE
LATE MORNING AND AFTERNOON HOURS. BY THE TIME THE LOSS OF CLOUD ICE
OCCURS...MOST OF THE FORCING/LIFT HAS EXITED THE AREA...THUS LITTLE
MORE THAN PATCHY -FZDZ/-DZ OR FLURRIES EXPECT BY AND AFTER 18Z.
GIVEN THE FAST MOVEMENT OF THE SYSTEM...MOST SNOW AMOUNTS LOOK TO BE
1/2 TO 2 INCHES.
BRIEF BREAK LATE THU AFTERNOON/EVENING BEFORE THE NEXT NORTHWEST
FLOW SHORTWAVE BEGINS TO IMPACT THE AREA BY LATE THU NIGHT THRU FRI
INTO FRI NIGHT. BULK OF THE DEEPER MOISTURE/SATURATION AND STRONGER
OF THE LOWER LEVEL THERMODYNAMIC FORCING AND DYNAMIC LIFT WITH THIS
SHORTWAVE TROUGH PASS ACROSS THE NORTHEAST HALF OF THE FCST AREA ON
FRI. GIVEN TIGHTER MODEL CONSENSUS...RAISED PRECIP CHANCES OVER THE
NORTHEAST HALF OF THE FCST AREA INTO THE 60-80 PERCENT RANGE FOR
FRIDAY. MODELS DIFFER ON NORTHWARD EXTENT OF THE 925-850MB WARM
LAYER FRI...NAM ONE OF THE WARMER/GFS ONE OF THE COLDER...WHICH
IMPACTS PRECIP TYPE ACROSS THE CENTRAL 1/3 TO 1/2 OF THE FCST AREA.
DEPTH OF MOISTURE AND PRESENCE OF ICE IN THE CLOUDS ALSO A CONCERN
OVER THE SOUTHWEST HALF OF THE FCST AREA ALSO A CONCERN ON FRI.
DEPENDING ON WHICH MODEL IS MORE CORRECT...PRECIP IN A BAND 50 MILES
EITHER SIDE OF I-90 COULD BE -RA/-FZRA/SLEET OR SNOW. WITH DEEPER
MOISTURE/STRONGER LIFT NORTH OF THIS AREA...WHATEVER PRECIP OCCURS
LOOKS TO BE LIGHT...WITH AFTERNOON TEMPS WARMING INTO THE MID/UPPER
30S ALLEVIATING MUCH OF THE ICING POTENTIAL. FURTHER NORTH IN
CLARK/TAYLOR COUNTIES...AIRMASS LOOKS TO REMAIN COLD ENOUGH FOR
MOSTLY SNOW...WITH AS MUCH AS 2-4 INCHES POSSIBLE. MAY YET NEED A
WINTER WEATHER ADVISORY FOR THE NORTH END OF THE FCST AREA FRI INTO
FRI EVENING...BUT WILL GET PAST THE THU SYSTEM AND WAIT FOR A BETTER
MODEL CONSENSUS ON THE LOWER LEVEL THERMAL PROFILE.
COLDER/DRIER CANADIAN HIGH PRESSURE BUILDS SOUTHEAST ACROSS MN/IA/WI
FOR SAT/SAT NIGHT. HOWEVER...WITH SOME BROADER 850-500MB CYCLONIC
FLOW OVER THE WESTERN GREAT LAKES...APPEARS SOME MOISTURE AROUND
850MB TO LINGER OVER THE AREA. WITH THE LOWER LEVEL COLD ADVECTION
PUTTING THE SQUEEZE ON THE AIRMASS...MAY BE SOME FLURRIES AROUND THE
AREA SAT/SAT EVENING BUT LEFT SAT/SAT NIGHT DRY FOR NOW.
FAVORING THE MODEL/ENSEMBLE CONSENSUS...TRENDED TOWARD A BLEND OF
THE NUMERICAL GUIDANCE LOWS/HIGHS FOR TONIGHT THRU SAT NIGHT. SOME
CONCERN HIGHS FRI MAY BE TOO WARM IF COLDER/STRONGER MODELS ARE
MORE CORRECT AND PRECIP IS MORE WIDESPREAD DURING THE DAY.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
316 PM CDT WED MAR 13 2013
13.00Z/13.12Z MEDIUM RANGE MODELS IN MODEST AGREEMENT SUN THRU MON
AS A STRONGER SHORTWAVE TROUGH DIGS THRU THE NORTHERN ROCKIES SUN
THEN INTO THE UPPER MIDWEST BY MON. OVERALL TREND IS A BIT SLOWER/
STRONGER...WITH MODELS FLIP-FLOPPING A BIT ON TIMING/STRENGTH.
MODEST BETWEEN MODEL AGREEMENT CONTINUES MON NIGHT-WED AS THIS
TROUGH MOVES EAST AND THRU THE EASTERN CONUS AND FLAT RIDGING MOVES
ACROSS CENTRAL NOAM. HOWEVER MORE BETWEEN MODEL TIMING DIFFERENCES
BY WED...FASTER GFS VS. SLOWER ECMWF WITH THE NEXT ENERGY COMING
THRU THE FLOW...START TO HAVE A BIG IMPACT ON THE POTENTIAL SENSIBLE
WEATHER FOR DAY 7. FCST CONFIDENCE AVERAGE SUN-TUE THEN ON THE LOW
SIDE WED. CAN HIGH PRESSURE REMAINS OVER THE UPPER MIDWEST SUN FOR
WHAT SHOULD BE A QUIET WEATHER DAY WITH CONTINUED BELOW NORMAL
TEMPS. BY SUN NIGHT AND FOR MON/MON NIGHT THE NEXT STRONGER
TROUGH...SFC LOW AND ROUND OF DEEP LAYERED FORCING/LIFT SPREAD
ACROSS THE REGION. CONSISTENT SIGNAL FOR THE AREA TO RECEIVE PRECIP
CENTERED ON MON. MODEL CONSENSUS PRECIP CHANCES INCREASING SUN
NIGHT...60-70 PERCENT MON AND DECREASING MON NIGHT LOOK GOOD UNTIL
THE TIMING/STRENGTH DETAILS BECOME CLEARER. FAVORING THE MODEL
CONSENSUS...APPEARS BULK OF THE PRECIP WITH THIS SYSTEM WOULD FALL
AS SNOW BUT AMOUNTS REMAIN IN QUESTION. DRY/COOL CAN HIGH PRESSURE
SETTLES ACROSS THE REGION FOR TUE. BY WED...FASTER GFS SPREADS THE
NEXT ROUND OF FORCING/LIFT AND WINTRY PRECIP INTO THE AREA WHILE
SLOWER ECMWF HOLDS THE AREA DRY UNDER THE CAN HIGH PRESSURE. WITH
LITTLE FCST CONFIDENCE BY WED...SMALL CONSENSUS PRECIP CHANCE WED OK
FOR NOW. GIVEN CAN HIGH PRESSURE OR WINTRY PRECIP PRODUCING SYSTEMS
IMPACTING THE REGION...MODEL CONSENSUS TEMPS A CATEGORY OR TWO BELOW
NORMAL LOOK WELL TRENDED FOR DAYS 4-7.
&&
.AVIATION...TONIGHT AND THURSDAY
639 PM CDT WED MAR 13 2013
THE MAIN FOCUS WITH THE TAFS IS WITH THE SNOW MOVING IN LATE
OVERNIGHT INTO TOMORROW MORNING. IFR CONDITIONS ARE EXPECTED TO
DEVELOP AS THE LIGHT SNOW MOVES IN AROUND 10Z AT RST AND 12Z AT
LSE AS THE NEXT SYSTEM MOVES INTO THE REGION. HIGH LEVEL CLOUD
COVER IS ALREADY SPREADING IN FROM THE NORTHWEST IN ADVANCE OF
THIS SYSTEM...BUT CONDITIONS WILL STAY VFR UNTIL THE SNOW BEGINS
TO FALL TOMORROW MORNING. VISIBILITY SHOULD DROP TO AROUND 2SM OR
LESS AT TIMES WITH THE SNOW WITH RST MORE LIKELY TO SEE IFR
CEILINGS OCCUR AS WELL.
THE 13.22Z RAP AND 13.18Z NAM/GFS ARE HINTING THAT THE LOW LAYERS
DRY OUT FAIRLY QUICKLY AS THE LIFT SHIFTS TO THE EAST WITH IFR
CONDITIONS SCATTERING OUT BEFORE 18Z. WITH THIS WEAKENING LIFT AND
LOWER RH...AM NOT AS CONFIDENT IN THE FREEZING DRIZZLE
OCCURRING...SO HAVE PULLED THAT MENTION WITH THESE TAFS. WINDS
WILL START OUT OF THE WEST THIS EVENING BEFORE SHIFTING AROUND TO
THE SOUTHEAST LATER TONIGHT BUT MAINLY STAYING ON THE LIGHT SIDE
WITH SOME 10-12KT SUSTAINED WINDS EXPECTED FOR A BRIEF PERIOD
TOMORROW MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 PM CDT WED MAR 13 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GOODLAND KS
308 AM MDT THU MAR 14 2013
.SHORT TERM...(TODAY AND THURSDAY)
ISSUED AT 308 AM MDT THU MAR 14 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOWS LARGE SCALE TROUGH IN
PLACE ACROSS NEW ENGLAND AND A RIDGE CENTERED ACROSS THE SOUTHWEST
US. BETWEEN THESE FEATURES NW FLOW EXTENDS ACROSS THE NORTHERN AND
CENTRAL PLAINS. EMBEDDED WITHIN THE MEAN FLOW SEVERAL WEAK SHORTWAVE
TROUGHS ARE PRODUCING HIGH CLOUDS WHICH ARE QUICKLY STREAMING FROM
THE NW TO SE ACROSS THE CWA. SOUNDS ARE VERY DRY SO DESPITE PRESENCE
OF ELEVATED FORCING WE SHOULD CONTINUE TO SEE DRY CONDITIONS.
H5 RIDGE IN OVER THE SOUTHWEST US IS PROGGED TO FLATTED WITH NW FLOW
TRANSITIONING TO WESTERLY FLOW BY FRIDAY. BL FLOW WILL CONTINUE TO
BE WESTERLY/DOWNSLOPE TODAY WITH DRY/WARM AIRMASS EXPECTED TODAY AND
FRIDAY. H85 TEMPS ARE ADVERTISED TO BE 2-3C WARMER THAN WED AND ON
FRI ALMOST 5-10C WARMER. ACCOUNTING FOR SIMILAR BIAS WE COULD SEE
TEMPS IN THE LOW TO MID 70S FOR MOST LOCATIONS TODAY AND 80F OR
WARMER ON FRI. THE COMBINATION OF WARM TEMPS/VERY DRY
CONDITIONS...COMBINED WITH INCREASING WINDS FRI AFTERNOON COULD LEAD
TO DEVELOPMENT OF CRITICAL FIRE CONDITIONS. RIGHT NOW CALCULATED RH
VALUES RANGE FROM NEAR 10 PERCENT IN OUR SOUTHWEST TO AROUND 15
PERCENT IN THE NORTH. WITH UNIDIRECTIONAL WESTERLY FLOW AND
STRENGTHENING SURFACE TROUGH WE SHOULD SEE AT LEAST BREEZY
CONDITIONS DEVELOP FRI AFTERNOON THOUGH LOCATION/MAGNITUDE OF
STRONGEST GUSTS IS STILL IN QUESTION. LOWEST RH VALUES AND WINDS IN
HE 20-25MPH RANGE MAY NOT OVERLAP BUT IT COULD BE CLOSE. WILL NOT
ISSUE ANY FIRE WEATHER HIGHLIGHTS DURING THIS FORECAST CYCLE AND WILL
ALLOW SUBSEQUENT SHIFTS TO FINE TUNE.
A BACKDOOR COLD FRONT WILL DROP SOUTH OVER THE CWA BY SATURDAY. WEAK
ENERGY WITHIN MEAN W/NW FLOW AHEAD OF THIS FRONT AND ELEVATED
INSTABILITY COULD SUPPORT SHOWER DEVELOPMENT LATE FRIDAY NIGHT WITH
INCREASING COVERAGE WITH FROPA SAT AND APPROACHING SHORTWAVE TROUGH
OVER THE PAC NW SAT NIGHT. MOISTURE PROFILES REMAIN DRY BELOW 600MB
THROUGH SAT AND REALLY DO NO BEGIN TO COMPLETELY MOISTEN UNTIL
SATURDAY AFTERNOON/EVENING. MOISTURE ADVECTION IS ALSO FAIRLY
UNIMPRESSIVE AHEAD OF THIS FRONT WITH BETTER MOISTURE RETURN
GENERALLY IN THE SOUTH. I DECIDED AGAINST INCREASING POPS SAT/SAT
NIGHT BEYOND CHANCE CATEGORY AND LEANED TOWARDS THE LOWER END OF
GUIDANCE ON QPF WITH PRECIP THAT OCCURS EXPECTED TO BE ON LIGHTER
SIDE. WITH MOST GUIDANCE ON THE WARMER SIDE RAIN SHOWERS WILL
LIKELY BE FAVORED WITH ONLY A BRIEF RAIN/SNOW MIX POSSIBLE LATE
SAT NIGHT ASSUMING WE SEE EVAPORATIVE COOLING PROCESSES. I DOUBT
WE WOULD SEE MUCH SNOW ACCUMULATION SAT NIGHT IF WE DID
TRANSITION OVER WITH LIGHT PRECIP RATES AND WARM GROUND TEMPS
EXPECTED.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 308 AM MDT THU MAR 14 2013
MODELS HAVE COME INTO SOMEWHAT BETTER AGREEMENT WITH THE WEATHER
SYSTEM EXPECTED TO SWING ACROSS THE PLAINS SUNDAY EVENING INTO
MONDAY MORNING...HOWEVER QUESTIONS STILL LINGER WITH RESPECT TO
TEMPERATURES AND THUS WEATHER TYPES.
THE GFS...CANADIAN AND EUROPEAN MODELS ARE IN FAIRLY GOOD AGREEMENT
WITH RESPECT TO THE TIMING OF STRONG UPPER LEVEL SHORTWAVE AND
DEVELOPMENT OF A SURFACE LOW AS THE SHORTWAVE MOVES ACROSS THE
PLAINS. THE GFS MODEL STANDS OUT FROM THE CANADIAN AND EUROPEAN
MODELS IN THAT IT IS STILL FORECASTING MUCH WARMER TEMPERATURES
DURING THE AFTERNOON ON SUNDAY. THE EUROPEAN AND CANADIAN ARE
SUGGESTING A COOLER...MORE STABLE ATMOSPHERE WHICH WOULD LIMIT
INSTABILITY AND WOULD GIVE A BETTER CHANCE AT SOME WINTRY
PRECIPITATION EARLY ON SUNDAY MORNING. THEREFORE...FOR THE TIME
BEING A RAIN SNOW MIX HAS BEEN MENTIONED FOR ROUGHLY THE NORTHERN
HALF OF THE FORECAST AREA SUNDAY MORNING DUE TO TEMPERATURE
UNCERTAINTY. IF THE GFS PANS OUT...THERE WOULD BE A BETTER CHANCE OF
SOME THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT WILL MOVE
THROUGH SUNDAY EVENING. EITHER WAY...ALL THREE MODELS ARE
FORECASTING PRECIPITATION ALONG AND AHEAD OF THE COLD FRONT. THE
QUESTION THAT REMAINS IS WILL THERE BE THUNDERSTORMS AND THUS
HEAVIER PRECIPITATION AMOUNTS POSSIBLE. ANOTHER CAUSE FOR CONCERN IS
THAT THE CANADIAN AND EUROPEAN MODELS ARE SUGGESTING A WARM FRONT
WILL REMAIN OVER THE AREA THROUGHOUT THE DAY ON SUNDAY WITH
PRECIPITATION DEVELOPING ALONG THE FRONT. IF THIS WERE TO
OCCUR...THE POPS ARE UNDERDONE DURING THE DAY ON SUNDAY AND WOULD
NEED TO BE INCREASED IN LATER FORECAST CYCLES. ALL PRECIP DURING THE
DAYLIGHT HOURS ON SUNDAY SHOULD NOT BE FROZEN IN NATURE.
ONCE THE COLD FRONT PUSHES THROUGH SUNDAY NIGHT...PRECIPITATION
CHANCES WILL DECREASE. A BRIEF CHANGE TO SNOW IS FORECAST BEHIND THE
FRONT AS TEMPERATURES ALOFT COOL ENOUGH TO ALLOW SNOW TO REACH THE
GROUND WITHOUT MELTING. THE EUROPEAN MODEL IS ABOUT 6 HOURS SLOWER
THAN THE OTHER TWO MODELS. THIS WOULD MEAN A BETTER CHANCE FOR SNOW
BEHIND THE FRONT ACROSS MAINLY NORTHEAST PORTIONS OF THE FORECAST
AREA. TRIED TO REFLECT CHANCES OF PRECIPITATION DECREASING BEHIND
THE FRONT AFTER MIDNIGHT BASED ON MODEL GUIDANCE.
FOLLOWING THIS WEATHER SYSTEM...A RIDGE OF HIGH PRESSURE WILL BUILD
IN ACROSS THE ROCKIES...LEADING TO DRY WEATHER ACROSS THE HIGH
PLAINS SINCE ANY DISTURBANCES WILL STAY WELL TO THE NORTH. MODELS
ARE BEGINNING TO SUGGEST A LARGE LONGWAVE TROUGH DEVELOPING OVER THE
WESTERN UNITED STATES AND MOVING ACROSS THE CENTRAL PLAINS BY THE
MIDDLE TO END OF NEXT WEEK. UNFORTUNATELY THE GFS AND EUROPEAN
MODELS HAVE LARGE DIFFERENCES BETWEEN THEIR SOLUTIONS WITH THE GFS
ABOUT A DAY FASTER THAN THE EUROPEAN. THE CR INIT PROCEDURE
SUGGESTED LIKELY POPS BEGINNING THURSDAY NIGHT BUT HAVE CUT THOSE IN
HALF TO START DUE TO THE LARGE DIFFERENCES IN MODEL SOLUTIONS.
AS THE RIDGE BUILDS IN...WARMER WEATHER WILL AGAIN RETURN. HAVE
INCREASED TEMPERATURES SLIGHTLY AS THE PATTERN WILL BE FAVORABLE FOR
A WARMING TREND. TEMPERATURES SHOULD BE ABOVE NORMAL FROM THIS
TUESDAY ONWARD WITH NEAR NORMAL TEMPERATURES BEHIND THE COLD
FRONT THIS MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1000 PM MDT WED MAR 13 2013
FOR KGLD AND KMCK...VFR THROUGH THE PERIOD. A SFC TROUGHS WILL
MOVE ACROSS THE AREA DURING THE FIRST 12 HOURS OF THE TAF PERIOD
WHERE WINDS WILL START THE PERIOD FROM THE WEST/SOUTHWEST AROUND
10KTS VEERING TO THE NORTHWEST AROUND 10KTS BY EARLY AFTERNOON
BEFORE BACKING TO THE WEST BY 00Z. FROM 00Z TO 06Z WINDS WILL BACK
FURTHER TO THE SOUTHWEST AT 5-10KTS. CLOUDINESS WILL BE LIMITED TO
CIRRUS LEVEL PERIODICALLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...99
AREA FORECAST DISCUSSION
NWS TOPEKA KS
339 AM CDT THU MAR 14 2013
.DISCUSSION...
0Z UPPER AIR DATA SHOWED RATHER WIDESPREAD 60M-PLUS 500MB HEIGHT
RISES FROM THE NORTHERN AND CENTRAL PLAINS INTO THE OHIO VALLEY AS A
DEEP UPPER LOW WAS MOVING OUT OF THE LATTER REGION. 850MB TEMPS FROM
THE HIGH PLAINS RAOBS WERE AT LEAST 10C. 07Z SURFACE PRESSURES
FALLING NICELY OVER THE MISSOURI VALLEY AHEAD OF A WEAK TROF.
WEST LOW LEVEL WINDS ALONG AND AHEAD OF THE TROF WILL USHER THE
WARMER AIRMASS EAST THIS MORNING AND EARLY THIS AFTERNOON WITH WEAK
NORTHERLY WINDS TAKING HOLD BY LATE DAY. WITH 850MB TEMPS AROUND 10C
WARMER THAN WEDNESDAY EVENING AND ONLY THIN CIRRUS ALOFT...HIGHS
NEAR 70 ARE ON TRACK. WEST WINDS RETURN OFF THE SURFACE TONIGHT AND
PERSIST THROUGH MUCH OF FRIDAY WITH 850MB TEMPS RISING ANOTHER 3-5C.
DEEPER MIXING VIA NEAR UNIDIRECTIONAL FLOW WILL SUPPORT EVEN WARMER
TEMPS...THOUGH STILL 3-5F SHORT OF RECORD VALUES. AT THIS POINT
RELATIVE HUMIDITIES AND WIND SPEEDS BOTH FALL SHORT OF MUCH OF A
FIRE WEATHER CONCERN.
COLD FRONT WILL SURGE SOUTH THROUGH THE AREA BY SATURDAY MORNING DRY
WITH MOISTURE VIA THE DEEP WESTERLY FLOW RATHER LIMITED. MOISTURE
PROFILES IMPROVE SOMEWHAT FOR SATURDAY INTO SUNDAY BUT A LACK OF
PERSISTENT FORCING AND STILL DRY AIR AROUND 850MB KEEPS PRECIP
CHANCES ON THE MODEST SIDE. BEST CHANCES SHOULD COME SUNDAY NIGHT
WHEN A STRONGER AND MORE AGREED UPON WAVE BREAKS DOWN THE WESTERN
RIDGE AND ENTERS THE PLAINS. GUIDANCE TEMPERATURES FOR SATURDAY VARY
QUITE A BIT WITH HOW STRONG THE COLD AIR ADVECTION WILL BE...BUT
LEVELS SOME 25-30F BELOW FRIDAYS LEVELS ARE LIKELY. THERE WILL BE
SOME CONCERN FOR LIGHT MIXED PRECIP AROUND SUNRISE OF SUNDAY AND
MONDAY FOR NORTHERN LOCATIONS WITH LOWS AROUND FREEZING...THOUGH A
MODIFYING AIRMASS AND MORE PERSISTENT CLOUD KEEP MONDAYS CONCERN
MORE LIMITED. THE UPPER RIDGE REBUILDS TO THE WEST TUESDAY AND
SLIDES EAST WEDNESDAY FOR WARMING AND DRY CONDITIONS.
65
&&
.AVIATION...
MODELS SHOW LITTLE IN THE WAY OF FORCING OR DEEP MOISTURE. THEREFORE
A VFR FORECAST IS EXPECTED TO PERSISTS WITH A WEAK SFC TROUGH MOVING
ACROSS THE AREA THROUGH THE DAY THURSDAY. THE RAP AND NAM SHOW THE
LOW LEVEL JET INCREASING TO AROUND 40KTS OVERNIGHT SO CONTINUED WITH
LLWS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
115 AM EDT THU MAR 14 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 421 PM EDT WED MAR 13 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW DEEP UPR TROF/
CLOSED UPR LO CENTERED JUST S OF JAMES BAY MOVING STEADILY TO THE
E...ALLOWING A RDG OVER THE ROCKIES TO EXPAND TO THE E...WITH
00Z-12Z H3 HGT RISES UP TO 150M EVIDENT OVER THE NRN PLAINS/UPR MS
RIVER VALLEY. ALTHOUGH A STEADY NNW FLOW BTWN ASSOCIATED SFC LO OVER
SE CANADA AND HI PRES RDG AXIS STRETCHING FM NW ONTARIO INTO THE
CENTRAL PLAINS IS PUSHING H85 TEMPS AS LO AS -13C TO -15C INTO THE
UPR LKS...THE AIRMASS IMMEDIATELY UPSTREAM IS SO DRY PER 12Z INL
RAOB THAT THERE ARE NO -SHSN OR EVEN MUCH IN THE WAY OF LK CLDS OVER
UPR MI ATTM. LOOKING A BIT FARTHER TO THE NW...THERE WAS SOME SC
NOTED EARLIER OVER PORTIONS OF NW ONTARIO ASSOCIATED WITH A BIT MORE
MSTR SHOWN ON THE 12Z YPL RAOB...BUT SUBSIDENCE ASSOCIATED WITH THE
APRCHG H3 HGT RISES/SFC ACYC FLOW AS WELL AS SOME DAYTIME HEATING
HAS CAUSED THIS CLD TO DISSIPATE. FARTHER TO THE NW...A SHRTWV
MOVING THRU ALBERTA AND INTO SASKATCHEWAN IS ROUNDING THE UPR RDG
OVER THE ROCKIES. MID/HI CLDS AHEAD OF THIS DISTURBANCE AND
ASSOCIATED WARM FNT OVER THE HI PLAINS ARE PUSHING E THRU THE
DAKOTAS/SCENTRAL CANADA THIS AFTN.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/IMPACT ON TEMPS.
TNGT...ALTHOUGH LK CLDS HAVE DISSIPATED WITH ARRIVAL OF DRIER AIR/
DAYTIME HEATING WITH HIER MARCH SUN ANGLE THAT TENDS TO CAUSE
SUBSIDENCE OVER LK SUP...CONCERNED SOME CLDS WL REFORM THIS EVNG
WITH LOSS OF HEATING/ARRIVAL OF MSTR NOTED IN NW ONTARIO IN THE
PRESENCE OF H85 TEMPS NEAR -12C AND THEN SPREAD INLAND INTO MAINLY
THE NCENTRL AND ERN CWA IN NW FLOW AHEAD OF APRCHG HI PRES RDG AXIS.
BUT AS THE HI PRES RDG AXIS APRCHS FM THE W...INCRSG SUBSIDENCE/MORE
ACYC LLVL FLOW IS FCST TO SINK THE SUBSIDENCE INVRN LO ENUF ANY LO
CLD SHOULD DSPT W-E. ALTHOUGH FCST H85 TEMPS ARE MARGINAL FOR LES...
LO INVRN BASE 2-3K FT AGL WL LIMIT LES TO PERHAPS SOME FLURRIES OVER
THE ERN ZNS DOWNWIND OF THE LK IN LLVL NW FLOW. PREVIOUS FCST HAD A
REASONABLE HANDLE ON THESE EXPECTATIONS...SO MADE FEW CHANGES TO
THESE GRIDS. SOME MID/HI CLDS WELL IN ADVANCE OF APRCHG SHRTWV/WARM
FNT TO THE W ARE FCST TO MOVE INTO THE WRN ZNS LATE TNGT. BUT WITH A
PERIOD OF MAINLY CLR SKIES/LGT WINDS...WL MAINTAIN MIN TEMPS FCST
NEAR LO END OF GUIDANCE OVER MUCH OF THE INTERIOR W HALF.
THU...SHRTWV NOW MOVING THRU SCENTRAL CANADA OVER TOP OF ROCKIES RDG
IS FCST TO MOVE THRU NW ONTARIO. ALTHOUGH CLD WL OVERSPREAD UPR MI
W-E AHEAD OF THE WARM FNT...PASSAGE OF SHARPER DPVA/DEEP LYR QVECTOR
CNVGC TO THE N CLOSER TO TRACK OF DISTURBANCE AS WELL AS LIMITED
DEPTH OF ABSOLUTE MSTR RETURN SHOULD RESULT IN A DRY DAY. H85 TEMPS
ARE FCST TO RISE TO BTWN ABOUT -2C OVER THE W AND -8C OVER THE E BY
00Z FRI AS A SW FLOW DVLPS ON THE WRN FLANK OF RETREATING HI PRES...
SO EXPECT A WARMER DAY ESPECIALLY OVER THE W HALF.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 421 PM EDT WED MAR 13 2013
UPPER LEVEL PATTERN STARTS OFF LONG TERM WITH ELONGATED TROUGH OVER
MOST OF NORTHERN AND EASTERN CANADA AND RIDGING OVER WESTERN CANADA.
OVER TIME RIDGE IS FLATTENED AS TROUGHING OVR CANADA SETTLES INTO
NORTHERN TIER OF CONUS THROUGH THE UPCOMING WEEKEND. ZONAL WNW FLOW
RESULTS AND WILL BRING STRONGER SHORTWAVE ACROSS NORTHERN PLAINS AND
UPPER GREAT LAKES THURSDAY NIGHT AND FRIDAY. TRICKY SYSTEM WITH
REGARD TO NORTHERN EXTENT OF HEAVIER SNOW. AS ALLUDED TO YDY...WILL
GREATLY DEPEND ON HOW FAR SOUTH SFC-H85 BAROCLINIC ZONE ALLIGNS IN
WAKE OF NORTHERN STREAM SHORTWAVE MOVING THROUGH THURSDAY NIGHT. GFS
AND GEM-NH FARTHER SOUTH /12Z GFS TRENDED EVEN FARTHER SOUTH/ WHILE
NAM IS MUCH FARTHER NORTH. ECMWF/UKMET A COMPROMISE...BUT THE ECMWF
DID TREND FARTHER SOUTH COMPARED TO THE 12Z RUN FROM YDY/12 MARCH.
SEEMS LIKE THE NAM IS BECOMING MORE OF A NORTHERN OUTLIER...SO WILL
TEND TO TREND AWAY FROM THAT IDEA AND ANY MODELS THAT ARE
INITIALIZED OFF OF IT SUCH AS OUR LOCAL WRF. STILL THINK THAT THE
LOCATION OF TIGHTER LOW-LEVEL TEMPERATURE GRADIENT WILL BE
ULTIMATELY WHERE HEAVIEST QPF/SNOW SETS UP ON FRIDAY AS SHORTWAVE
AND SFC-H85 LOWS MOVE IN FROM NORTHERN PLAINS.
WHERE THE TIGHT THERMAL GRADIENT OCCURS THERE IS A POTENTIAL FOR A
NARROW STRIPE OF HEAVY SNOW DUE TO LOW-MID LEVEL FRONTOGENESIS AMD
DIVERGENCE ALOFT FROM RIGHT ENTRANCE REGION OF JET STREAK DROPPING
INTO GREAT LAKES FROM ONTARIO ALONG WITH DECENT MOISTURE ADVECTION
WITH H7 MIXING RATIOS 3-4G/KG. SFC-H85 LOWS/LOW-LEVEL FLOW IS
SHOWING A STRENGTHENING TREND OVERALL AS WELL. BASED ON MODEL
CONSENSUS...SEEMS LIKE BETTER CHANCE FOR ENHANCEMENT/HEAVIER SNOW TO
COME TOGETHER MAY END UP JUST TO OUR SOUTH. WILL KEEP POPS LIKELY
TOWARD THE WEST AND SOUTH...WHERE MODEL AGREEMENT IS HIGHER THAT
SNOW OCCURS. MAY NEED HEADLINES...LIKELY ADVISORIES...IN THESE AREAS
FRIDAY INTO FRIDAY EVENING. WWD DAY2 GRAPHICS INDICATE SWATH OF 2-4
INCHES OF SNOW FRIDAY ALONG WI BORDER...WITH JUST A COUPLE INCHES
OVER NORTHERN UPR MICHIGAN. BASED ON CROSS SECTIONS FROM GFS AND
JUST THE LOOK FROM QPF FIELDS...COULD BE A VERY SHARP CUTOFF TO SNOW
ON NORTH SIDE. AS AGEOSTROPIC CIRCULATION WITHIN H85-H7 FRONTOGENEIS
OCCURS THERE ARE INDICATIONS THAT SUBSIDENCE AREA OVER NORTHERN UPR
MICHIGAN WILL DRAW INCREASINGLY DRIER AIR IN FROM CANADA. GRADIENT
OF SNOW AMOUNTS MAY END UP SIMILAR TO SNOW EVENT FROM LATE MARCH OF
2011 THAT IMPACTED FAR SOUTH CENTRAL CWA WITH OVER A FOOT OF SNOW
WHILE NORTHERN CWA ONLY SAW FLURRIES. WE SHALL SEE. ONCE SNOW TAPERS
OFF...DESPITE SUFFICIENT COLD AIR IN LOW-LEVELS...UNSURE ON EXTENT
OF LK EFFECT GIVEN CONCERNS WITH THE DRY AIR.
FAIRLY QUIET LATER FRIDAY NIGHT INTO SATURDAY MORNING. MAY SEE SOME
SNOW SHOWERS FLARE UP SATURDAY AFTN INTO SATURDAY NIGHT WITH ARRIVAL
OF SHORTWAVE/COLD AIR ADVECTION DRIVING H85 TEMPS DOWN TO NEAR -20C.
MODELS HINT AT SHARPER LOW-LEVEL TROUGH MOVING THROUGH SATURDAY
EVENING WHICH MAY ALSO ENHANCE THE SNOW. INCREASED POPS A BIT INTO
SATURDAY NIGHT. GIVEN FAVORABLE LOCATION OF DGZ WITHIN MOIST LAYER
PRESENT WITH LAKE EQLS UP TO 10KFT...MAY SEE SEVERAL INCHES OF
FLUFFY SNOW ALONG LK SUPERIOR. INVERSION LOWERS BLO 5KFT THROUGH
DAY ON SUNDAY...BUT ENOUGH COLD AIR LINGERS FOR NW FLOW AREAS TO SEE
SCT LK EFFECT SNOW SHOWERS.
ATTN THEN TURNS TO SHORTWAVE TROUGHING DIGGING ACROSS ROCKIES BY
SUNDAY HELPING TO DEEPEN SFC LOW ON THE LEE SIDE OF THE ROCKIES.
UPPER TROUGH/SFC LOW IS FORECAST TO HEAD EAST AND DEEPEN AS
SHORTWAVE IN THE NORTHERN BRANCH ATTEMPTS TO PHASE WITH THE SOUTHERN
STREAM SYSTEM. SFC LOW DEEPENS FURTHER AND LIFTS ACROSS GREAT LAKES
WHICH MAY LEAD TO A SIGNIFICANT SNOW STORM OVER PORTIONS OF THE
UPPER GREAT LAKES. UP TO 12Z THERE WAS ACTUALLY GOOD AGREEMENT FROM
THE ECMWF AND GFS ON TRACK OF THE LOW. 12Z ECMWF JOGGED FARTHER WEST
THOUGH IT WOULD STILL BE MAINLY A SNOW EVENT. WAVES PRODUCING THIS
WEATHER SYSTEM ARE STILL WELL TO THE NORTH...UNDERSTATEMENT...OVER
THE NORTHWEST TERRITORIES OF CANADA...AND IN THE VCNTY OF THE NORTH
POLE. THERE IS A LOT OF INTERACTION THAT HAS TO OCCUR YET BTWN THESE
WAVES...AND LIKELY OTHERS AS WELL...BEFORE A FINAL SOLUTION IS
DETERMINED. CERTAINLY A SYSTEM TO WATCH THOUGH AS IT WILL HAVE GULF
MOISTURE TO WORK ON. CONVECTION TO THE SOUTH TOO SO THAT INTERACTION
WILL NEED TO BE ADDRESSED BY MODELS AS WELL. MID SHIFT PUT A MENTION
IN HWO...WHICH SEEMS LIKE GOOD CALL IN THIS SITUATION. STRONGER
SYSTEM DRAWS DOWN CONTINUAL COLD AIR ACROSS LK SUPERIOR THROUGH
MIDWEEK SO PUT CHANCE POPS IN OVER NORTHERN CWA. LAST PANELS OF GFS
AND ECMWF INDICATE SOME POTENTIAL FOR MODERATING TEMPS TOWARD LAST
WEEK OF MARCH AS MEAN TROUGH ATTEMPTS TO SHIFT INTO EASTERN CANADA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 114 AM EDT THU MAR 14 2013
LAKE EFFECT CLOUDS HAVE SHIFTED SOUTH OF CMX AND STARTED TO DISSIPATE
AS A HIGH PRES RIDGE BUILDS INTO THE REGION AND THE SUBSIDENCE
INVERSION LOWERS. ALTHOUGH SOME MID/HI CLOUDS WILL SPREAD ACROSS THE
AREA ON THU...PREVAILING DRY LOW LEVEL AIR WILL RESULT IN VFR
CONDITIONS FOR MOST OF THE DAY. INCREASING LOW LEVEL MOISTURE IS
EXPECTED TO MOVE IN BY THE LATE AFTERNOON AND EVENING IN A
STRENGTHENING PATTERN WITH MVFR CIGS DEVELOPING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EDT WED MAR 13 2013
AS HI PRES RIDGE AXIS MOVES IN FROM THE W TONIGHT...THE PRES
GRADIENT WILL WEAKEN OVER LAKE SUP...CAUSING NNW WINDS UP TO 30 KTS
LATE THIS AFTERNOON OVER THE E HALF TO DIMINISH AND FREEZING SPRAY
TO END. WINDS WILL SHIFT TO THE SW ON THU AS THE RIDGE AXIS MOVES TO
THE E...BUT WINDS WILL BE UNDER 20 KTS UNTIL LATE IN THE DAY OVER
THE W AS ANOTHER TROF APPROACHES FROM THE NW AND SHARPENS THE PRES
GRADIENT.
DUE TO THAT TIGHTER PRESSURE GRADIENT...W WINDS TO 25 KTS INCREASE TO
30 KTS WHILE SHIFTING N-NW ON THU NIGHT. SLIGHT RISK THAT GALE GUSTS
COULD OCCUR RIGHT IN WAKE OF THE WIND SHIFT THURSDAY EVENING OVER
EASTERN LK SUPERIOR. EXPECT N-NE WINDS TO 25 KTS THROUGH FRI AS LOW
PRESSURE PASSES SOUTH OF THE REGION. AFTER LIGHTER WINDS INTO SAT
MORNING ANOTHER TROUGH WILL SHIFT WINDS TO NW TO 25 KTS SAT NIGHT.
WINDS DIMINISH ON SUN BUT INCREASE YET AGAIN LATE ON MON AS STRONG
LOW PRESSURE SYSTEM LIFTS ACROSS THE UPR LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...JLB
MARINE...KC/JLA
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1213 AM CDT THU MAR 14 2013
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.
&&
.UPDATE... /ISSUED AT 912 PM CDT WED MAR 13 2013/
UPDATED THE GRIDS FOR LATER TONIGHT TO ACCOUNT FOR A NARROWER
BAND OF SNOW THAN WAS ANTICIPATED EARLIER. THE HI RES MODELS AND
MESOSCALE MODELS OF HOPWRF...NAM...AND RAP ALL INDICATE A NARROW
BAND OF MODERATE SNOW SLIDING SOUTHEAST ACROSS CENTRAL MN...
INTO...OR JUST EAST OF THE TWIN CITIES METRO...AND ALONG THE
MISSISSIPPI RIVER OF SERN MN BY THURSDAY MORNING. 21Z RUN OF THE
HOPWRF IS SHIFTING THIS POTENTIAL A ROW OF COUNTIES FURTHER EAST.
WILL SEE A QUICK 1 TO 3 INCHES WITHIN 4 OR 5 HOURS WITH THIS BAND.
BEST TIMING WOULD BE BETWEEN MIDNIGHT AND 4 AM ACROSS CENTRAL
MN...3 TO 7 AM FOR THE TWIN CITIES METRO AND WRN WI...AND 5 TO 9
AM ACROSS SERN MN.
THINK THE POTENTIAL IS LOW ENOUGH ACROSS SWRN MN TO REMOVE MENTION
OF POP ALTOGETHER...ALTHOUGH A FEW FLURRIES ARE THEORETICALLY
POSSIBLE.
GRIDS ARE PUBLISHED AND TEXT PRODUCTS HAVE BEEN ISSUED.
BORGHOFF
&&
.PREV DISCUSSION... /ISSUED 350 PM CDT WED MAR 13 2013/
SEVERAL CONCERNS ONCE AGAIN THIS FORECAST PERIOD. A COUPLE OF
CLIPPER TYPE SYSTEMS WITH SOME P-TYPE ISSUES ASSOCIATED WITH THEM
AND THEN THE LONGER TERM TRENDS OF THE MORE SIGNIFICANT STORM
POSSIBLE LATER SUNDAY NIGHT INTO MONDAY NIGHT.
FIRST SHORT WAVE TROUGH TO MOVE INTO THE AREA LATE THIS EVENING
AND SPREAD RAPIDLY SOUTHEAST THROUGH 12Z. THICKNESS PROGS DO
INDICATE POSSIBLE LIGHT FREEZING RAIN THREAT INTO SOUTHWEST
MINNESOTA DURING THE LATE NIGHT/EARLY MORNING. WILL HAVE TO
MONITOR THIS THREAT THIS EVENING TO SEE IF THIS WILL BE WIDESPREAD
OR NOT. OTHERWISE IT REMAINS COLD ENOUGH FOR SNOW IN THE NORTHEAST
TWO THIRDS OF THE CWA OVERNIGHT. TIMING IS RATHER POOR FOR EAST
CENTRAL MN AS IT APPEARS THE BEST SHOT OF SNOW WILL BE AROUND THE
RUSH HOUR THURSDAY MORNING. AT THE MOMENT WE HAVE 1 TO 2 INCH
ACCUMULATIONS IN THIS QUADRANT THROUGH THE DAY THURSDAY.
BRIEF RESPITE IN THE PRECIPITATION THREAT EARLY THURSDAY NIGHT
BEFORE THE NEXT SHORT WAVE DROPS SOUTHEAST OVER THE AREA FOR FRIDAY.
FOLLOWED MORE OF A GFS SOLUTION DURING THE PERIOD...WHICH WOULD
FAVOR MAINLY SNOW OVER THE NORTHERN CWA. COULD BE A MIX OF
FREEZING RAIN/RAIN MORNING/EARLY AFTERNOON...BUT MUCH OF THIS
SHOULD FALL AS SNOW. FARTHER SOUTH...MIXED FREEZING RAIN AND SNOW
POSSIBLE IN THE SOUTHERN CWA...AND MAY CHANGE OVER TO JUST RAIN IN
THE AFTERNOON...AS THICKNESS VALUES REMAIN HIGH OVER THE FAR
SOUTH. STILL APPEARS WHATEVER REMAINS WILL CHANGE BACK OVER TO
LIGHT SNOW LATE IN THE AFTERNOON. FORECAST SNOW ACCUMULATION DOES
JUMP INTO THE ADVISORY REALM WITH 2 TO 5 INCHES MAINLY NORTH OF
MORRIS...GLENCOE AND RED WING LINE. WILL HAVE TO MONITOR SOUTHERN
AREAS EARLY FOR POSSIBLE MIXED PRECIPITATION HAZARDS.
COOL TEMPERATURES REMAIN INTO NEXT WEEK. LONG TERM MODELS CONTINUE
TO SHOW STRONG STORM MOVING INTO THE REGION LATER SUNDAY AND
LASTING THROUGH MONDAY. BOTH THE 12Z ECMWF AND GFS SHOW HEAVY
ACCUMULATIONS AND STRONG WINDS IN THE STORMS WAKE. THE 12Z ECMWF
OCCLUDES THE STORM EARLY MONDAY BUT REMAINS COLD ENOUGH FOR JUST
SNOW DURING THE PERIOD. THE GFS HINTS AT A POSSIBLE MIX
EARLY...BUT THE STRONG HEIGHT FALLS/DYNAMICS ASSOCIATED WITH THE
LOW SHOULD BE STRONG ENOUGH TO CHANGE ANY MIX IN THE SOUTH TO SNOW
FAIRLY RAPIDLY. THE LATEST TREND ON THE FIM MODEL ALSO INDICATES
THE DEEP LOW TRAVERSING EXTREME SOUTHERN MN AS WELL. SIGNIFICANT
IMPACTS WILL LIKELY OCCUR WITH THIS SYSTEM IF CURRENT TRENDS
CONTINUE.
&&
.AVIATION.../06Z TAF ISSUANCE/
BAND OF SNOW ACROSS NWRN MN WILL SLIDE SOUTHEAST ACROSS CNTRL/ERN
MN AND WRN WI TONIGHT AND EARLY THURSDAY. THE NARROW BAND SHOULD
IMPACT STC/MSP/RNH/EAU...BUT WILL BE MOST INTENSE ALONG THE MN/WI
BORDER BETWEEN 10-12Z. MVFR CONDS WILL ACCOMPANY THE SNOW...BUT
WILL FALL TO IFR IN THE HEAVIEST SNOW. NOT EXPECTING A LOT OF LOW
CIGS BEHIND IT AS CURRENT CONDITIONS INDICATE VFR IMMEDIATELY
SURROUNDING THE SNOW.
KMSP...SNOW IS STILL ON TRACK BETWEEN 09-13Z PER LATEST TRENDS AND
GOOD MESOSCALE MODEL CONSISTENCY. SHOULD SEE EMBEDDED IFR
CONDITIONS WITH A QUICK 1-2 INCHES OF SNOW DURING THIS TIME WITH
PREVAILING VFR CONDITIONS BEFORE AND AFTER. THE HEAVIEST PORTION
OF THE BAND AND MOST ACCUMULATION SHOULD OCCUR JUST EAST OF THE
TERMINAL.
/OUTLOOK FOR KMSP/
FRI...IFR/MVFR CIGS. CHC OF SN/FZRA/RA. WINDS N/NE 5-10 KTS.
SAT...MVFR/VFR CIGS. WINDS NW 5-10 KTS.
SUN...VFR EARLY...WITH MVFR/IFR CIGS/VSBYS IN SN LATE. WINDS E
5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/BORGHOFF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT WED MAR 13 2013
.SHORT TERM...TONIGHT INTO TOMORROW MORNING
904 PM CDT WED MAR 13 2013
THE MAIN SHORT TERM FOCUS IS ON THE SNOW POTENTIAL OVERNIGHT INTO
TOMORROW MORNING. THIS SYSTEM IS CURRENTLY IN EASTERN NORTH DAKOTA
WHERE A BAND OF SNOW IS SHOWING UP ON RADAR. HOWEVER...SOME OF
THIS SNOW IS NOT MAKING IT DOWN TO THE GROUND DUE TO A DRY LAYER
OBSERVED BETWEEN 900-700MB ON MPX/INL/ABR 14.00Z SOUNDINGS. THE
13.23Z AND PREVIOUS RUNS OF THE HRRR SEEM TO HAVE A GOOD HANDLE ON
THIS BAND OF SNOW AS IT DROPS DOWN INTO THE REGION OVERNIGHT WITH
IT BECOMING ALIGNED ALONG THE MISSISSIPPI RIVER BY 12Z TOMORROW
MORNING ALL THE WAY DOWN INTO NORTHEAST IOWA. MID LEVEL FORCING IS
RATHER WEAK AS THE MID LEVEL TROUGH IS NOT VERY DEEP. SO...MUCH
OF THE FORCING IS FROM LOW LEVEL WARM AIR ADVECTION AND ISENTROPIC
LIFT ON THE 285K SURFACE. THIS LIFT QUICKLY DROPS TO THE SOUTHEAST
TOMORROW MORNING...LEAVING THE REGION WITH A 3-5 HOUR CLIP FOR
THIS SNOW. CONSIDERED DROPPING DOWN THE 1-2 INCH SNOW BAND IN THE
FORECAST DOWN TO JUST AROUND AN INCH BECAUSE OF THE DRY WEDGE IN
PLACE...BUT THE POTENTIAL FOR SOME BANDING COULD LEAD TO SOME
LOCALLY HIGHER AMOUNTS THAT PERHAPS APPROACH TWO INCHES.
OVERALL...EXPECT THAT MOST OF THE AREA WILL JUST SEE A DUSTING TO UP TO
AN INCH OF SNOW FROM THIS BEFORE IT ENDS BY NOON TOMORROW MORNING.
AS FAR AS THE FREEZING DRIZZLE IS CONCERNED...THE ISENTROPIC LIFT
WEAKENS RATHER QUICKLY AND AM NOT VERY CONFIDENT THAT THERE WILL
BE ANY SORT OF LIFT LEFT AS THE COLUMN LOSES ICE THROUGH THE
MORNING. DUE TO THIS...WILL BE REMOVING THIS FROM THE FORECAST FOR
TOMORROW MORNING.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
316 PM CDT WED MAR 13 2013
13.00Z/13.12Z MEDIUM RANGE MODELS IN MODEST AGREEMENT SUN THRU MON
AS A STRONGER SHORTWAVE TROUGH DIGS THRU THE NORTHERN ROCKIES SUN
THEN INTO THE UPPER MIDWEST BY MON. OVERALL TREND IS A BIT SLOWER/
STRONGER...WITH MODELS FLIP-FLOPPING A BIT ON TIMING/STRENGTH.
MODEST BETWEEN MODEL AGREEMENT CONTINUES MON NIGHT-WED AS THIS
TROUGH MOVES EAST AND THRU THE EASTERN CONUS AND FLAT RIDGING MOVES
ACROSS CENTRAL NOAM. HOWEVER MORE BETWEEN MODEL TIMING DIFFERENCES
BY WED...FASTER GFS VS. SLOWER ECMWF WITH THE NEXT ENERGY COMING
THRU THE FLOW...START TO HAVE A BIG IMPACT ON THE POTENTIAL SENSIBLE
WEATHER FOR DAY 7. FCST CONFIDENCE AVERAGE SUN-TUE THEN ON THE LOW
SIDE WED. CAN HIGH PRESSURE REMAINS OVER THE UPPER MIDWEST SUN FOR
WHAT SHOULD BE A QUIET WEATHER DAY WITH CONTINUED BELOW NORMAL
TEMPS. BY SUN NIGHT AND FOR MON/MON NIGHT THE NEXT STRONGER
TROUGH...SFC LOW AND ROUND OF DEEP LAYERED FORCING/LIFT SPREAD
ACROSS THE REGION. CONSISTENT SIGNAL FOR THE AREA TO RECEIVE PRECIP
CENTERED ON MON. MODEL CONSENSUS PRECIP CHANCES INCREASING SUN
NIGHT...60-70 PERCENT MON AND DECREASING MON NIGHT LOOK GOOD UNTIL
THE TIMING/STRENGTH DETAILS BECOME CLEARER. FAVORING THE MODEL
CONSENSUS...APPEARS BULK OF THE PRECIP WITH THIS SYSTEM WOULD FALL
AS SNOW BUT AMOUNTS REMAIN IN QUESTION. DRY/COOL CAN HIGH PRESSURE
SETTLES ACROSS THE REGION FOR TUE. BY WED...FASTER GFS SPREADS THE
NEXT ROUND OF FORCING/LIFT AND WINTRY PRECIP INTO THE AREA WHILE
SLOWER ECMWF HOLDS THE AREA DRY UNDER THE CAN HIGH PRESSURE. WITH
LITTLE FCST CONFIDENCE BY WED...SMALL CONSENSUS PRECIP CHANCE WED OK
FOR NOW. GIVEN CAN HIGH PRESSURE OR WINTRY PRECIP PRODUCING SYSTEMS
IMPACTING THE REGION...MODEL CONSENSUS TEMPS A CATEGORY OR TWO BELOW
NORMAL LOOK WELL TRENDED FOR DAYS 4-7.
&&
.AVIATION...THROUGH 06Z FRIDAY
1140 PM CDT WED MAR 13 2013
MAIN FOCUS CONTINUES TO BE WITH THE BAND OF SNOW THAT HAS FORMED
ACROSS EASTERN NORTH DAKOTA AND WILL DROP DOWN INTO THE REGION
THURSDAY MORNING. VISIBILITY HAS DROPPED INTO THE 1-3SM RANGE
UNDER THE MAIN SNOW BAND AND EXPECT THAT THIS WILL BE THE CASE AT
RST/LSE THURSDAY MORNING AS THE SNOW MOVES THROUGH. CEILINGS HAVE
MAINLY BEEN MVFR TO VFR ACROSS THIS SNOW BAND...THOUGH THEY HAVE
BRIEFLY DROPPED DOWN TO IFR AS THE HEAVIEST SNOW COMES THROUGH.
SKIES DO CLEAR OUT QUICKLY AS THE SYSTEM COMES TO AN END...SO
EXPECT THAT THE WORST CONDITIONS WILL BE FAIRLY SHORT LIVED AT 3-5
HOURS THIS MORNING. SKIES SHOULD CLEAR OUT IN THE
AFTERNOON/EVENING...THOUGH SOME HIGH LEVEL CLOUD COVER WILL LIKELY
BE MOVING IN AHEAD OF THE NEXT SYSTEM.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
316 PM CDT WED MAR 13 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....RRS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
925 AM EDT THU MAR 14 2013
.UPDATE (TODAY - FRIDAY)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED UPPER LEVEL
PATTERN ACROSS THE CONUS. NORTHERN STREAM FLOW FORMS A LARGE
LONGWAVE RIDGE ACROSS THE INTER-MOUNTAIN WEST BEFORE CARVING A
LONGWAVE TROUGH DOWNSTREAM OVER THE EASTERN HALF OF THE NATION. THE
FLORIDA PENINSULA RESIDES AT THE BASE OF THIS DEEP TROUGH EMBEDDED
WITHIN A DEEP LAYER NW FLOW PATTERN. 12Z KTBW SOUNDING PROFILE SHOWS
A DRY COLUMN THROUGH A DEEP LAYER ABOVE OUR HEADS WITH A PW VALUE OF
ONLY AROUND 0.20". PROFILE BECOMES MORE MOIST ABOVE 25-30KFT AND
SHOULD ALLOW MORE SOME PASSING CIRRUS TODAY...ESPECIALLY ACROSS THE
SOUTHERN HALF OF THE AREA. OTHER THAN SOME PASSING CIRRUS...THE
FORECAST WILL FEATURE ABUNDANT SUNSHINE AND COOL TEMPERATURES FOR
MID MARCH THROUGH THE AFTERNOON HOURS. AREAS ALONG AND NORTH OF I-4
WILL STRUGGLE INTO THE UPPER 60S...WHILE LOCATIONS FURTHER SOUTH
REACH THE LOWER 70S. THESE READINGS ARE SEVERAL DEGREES BELOW
NORMAL.
AT THE SURFACE...A LARGE RIDGE OF HIGH PRESSURE IS EXPANDING ALONG
THE NORTHERN GULF COAST AND WILL SLOWLY APPROACH AND SETTLE OVER-TOP
THE PENINSULA DURING FRIDAY. SO...A FAIRLY TIGHT GRADIENT STILL IN
PLACE THROUGH MID-AFTERNOON WILL ALLOW FOR SOME GUSTY CONDITIONS AS
THE BOUNDARY LAYER BEGINS TO MIX OUT. HOWEVER THIS EVENING...THE
WEAKENING GRADIENT AND LOSS OF DIURNAL MIXING SHOULD SETTLE THOSE
WINDS DOWN AND EVENTUALLY ALLOW SOME PLACES TO DECOUPLE LATE ACROSS
THE INTERIOR NATURE COAST...AND POSSIBLY DOWN TOWARD HIGHLANDS/DE
SOTO/HARDEE COUNTIES. WHILE EVERYWHERE WILL BE CHILLY FOR MID MARCH
TONIGHT...THESE AREAS THAT DECOUPLE WILL HAVE THE BEST CHANCE AT
SOME PATCHY FROST TOWARD DAWN. WILL WAIT AND SEE THE 12Z GUIDANCE
PACKAGE NUMBERS...BUT A FROST ADVISORY MAY BECOME NECESSARY...
ESPECIALLY FOR PORTIONS OF THE INTERIOR NATURE COAST WHERE THE BEST
COMBINATION OF RIDGE POSITION...DEWPOINT RECOVERY...AND SOIL TYPE
WILL BE FOUND.
AFTER THE CHILLY EARLY MORNING...FRIDAY IS LOOKING TO BE A BEAUTIFUL
DAY WITH PLENTY OF SUNSHINE...LIGHT WINDS...AND TEMPERATURES INTO
THE 70S. ENJOY!
&&
.AVIATION...
VFR CONDITIONS WITH SOME HIGH CIRRUS. GUSTY NORTHERLY WINDS BACK TO
NW AND DIMINISH LATE AFTERNOON.
&&
.MARINE...
SMALL CRAFT ADVISORY CONTINUES THROUGH THIS AFTERNOON FOR ALL AREAS
EXCEPT TAMPA BAY. EXERCISE CAUTION LEVEL WINDS WILL EXIST ACROSS THE
BAY. A WEAKENING GRADIENT AS HIGH PRESSURE SETTLES OVER THE EASTERN
GULF WILL DROP WINDS AND SEAS BELOW HEADLINE CRITERIA BY LATE
TONIGHT...AND THROUGH AT LEAST THE FIRST HALF OF THE UPCOMING
WEEKEND.
&&
.FIRE WEATHER...
THE CURRENT RED FLAG WARNING LOOKS GOOD FOR POLK...PINELLAS...
SARASOTA...AND LEE COUNTIES. THE ENTIRE AREA WILL BE DRY...BUT FOR
NOW...WINDS APPEAR MARGINAL FOR A WARNING ELSEWHERE.
&&
PRELIMINARY POINT TEMPS/POPS...
TPA 67 45 72 53 / 0 0 0 10
FMY 74 44 76 50 / 0 0 0 10
GIF 70 39 74 47 / 0 0 0 10
SRQ 68 44 71 53 / 0 0 0 10
BKV 67 35 74 45 / 0 0 0 10
SPG 68 51 72 59 / 0 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT UNTIL 4 PM EDT THIS AFTERNOON FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR LEE-PINELLAS-POLK-SARASOTA.
FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR CITRUS-
HERNANDO-LEVY-SUMTER.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR
BONITA BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO TARPON SPRINGS
OUT 20 NM-ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM-
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
902 AM CDT THU MAR 14 2013
.DISCUSSION...
758 AM CDT
JUST A QUICK BLURB AS SOME PERIODIC HEAVY SNOWFALL RATES CONTINUE
TO BE OBSERVED UPSTREAM...WITH EVEN A COUPLE CG LIGHTNING STRIKES
ACROSS NC IOWA. MPX AND DVN SOUNDINGS INDICATE STEEP LAPSE
RATES...WITH THE RAP EVEN ANALYZING THESE RATES TOWARD 8 C/KM IN
THE MID-LEVELS ATOP WHERE THE STRIKES OCCURRED. SHORT TERM GUIDANCE
ADVECTS THIS WITH THE SHORT WAVE ACROSS THE FAR WESTERN FORECAST
AREA /ROCKFORD TO OTTAWA TO GIBSON CITY AND WEST/ BETWEEN 16Z AND
20Z. SO IN THAT PERIOD THERE COULD BE A FEW BURSTS OF HALF MILE
VISIBILITY TYPE SNOW...WHICH COULD LEAD TO UP TO AN INCH OF
ACCUMULATION EVEN WITH TEMPS LIKELY HOVERING AROUND FREEZING AT
THAT TIME.
MTF
&&
.PREV DISCUSSION...
334 AM CDT
TODAY AND TONIGHT...
FORECAST CHALLENGE FOR THE DAY CONTINUES TO FOCUS ON THE PRECIP
TIMING AND INTENSITY OF THE CLIPPER SYSTEM...THAT SHOULD ARRIVE JUST
AFTER DAYBREAK ACROSS THE FAR NORTHWEST PORTIONS OF THE CWFA.
IR IMAGERY EARLY THIS MORNING CONTINUES TO SHOW MINIMAL CLOUD COVER
ACROSS THE CWFA AS THE WEAK ANTI-CYCLONIC FLOW THAT BROUGHT MOSTLY
SUNNY SKIES WEDNESDAY STEADILY RETREATS SOUTH. DESPITE MOSTLY CLEAR
SKIES FOR A PERIOD OF TIME...TEMPS HAVE ONLY RADIATED INTO THE
LOW/MID 20S WHILE SUBSIDENCE HAS ALLOWED DEW PTS TO PUSH INTO THE
MID TEENS. CIRRUS CLOUDS EARLY THIS MORNING ARE BEGINNING TO ARRIVE
ACROSS THE WESTERN COUNTIES OF IL...AS THE LEADING EDGE OF THE
CLIPPER SYSTEM APPROACHES. THIS CIRRUS SHIELD WILL ARRIVE ACROSS THE
REMAINDER OF THE CWFA ARND DAYBREAK.
UPSTREAM THE CLIPPER SYSTEM THAT HAS BEEN PROGGED FOR SEVERAL
DAYS...HAS PUSHED INTO THE UPPER MIDWEST EARLY THIS MORNING. SFC
OBSERVATIONS UNDERNEATH THE CLOUD SHIELD AND WHERE IT IS
PRECIPITATING...HAVE SUGGESTED ONSET OF PRECIP TO BE ABRUPT. OBS
HAVE GONE FROM NO SNOW TO LGT/MOD SNOW WITHIN MINUTES OF
ARRIVAL...AND VSBYS HAVE QUICKLY BEEN REDUCED TO ARND 1SM. WHEN THIS
SYSTEM WAS OVER NORTH DAKOTA OBS WERE SLIGHTLY LOWER WITH VSBYS ARND
1/2SM. CLOUD TOPS APPEAR TO BE COOLING WITH THE LATEST SCANS...AND
THIS INDICATES SOME STRENGTHENING MIGHT BE TAKING PLACE THE FURTHER
SOUTHEAST THE SYSTEM SLIDES.
GUIDANCE HAS BACKED OFF ON THE INTENSITY AND COVERAGE OF THE PRECIP
WITH THE SYSTEM TODAY...POSSIBLY A BY-PRODUCT OF THE LACK OF LLVL
MOISTURE AND HOW QUICKLY SATURATION TAKES PLACE. TIMING STILL LOOKS
GOOD WITH AN ARRIVAL ACROSS THE FAR NW CWFA ARND 14-15Z...STREAMING
SE FROM ROCKFORD/STERLING TO KANKAKEE/PAXTON BY 16-18Z.
THE DGZ REMAINS CONSISTENT ARND 10KFT AGL...WITH A GOOD SLUG OF LIFT
INTO THE CORE OF THE BEST GROWTH ZONE AT 15 TO 17Z...MAINLY WEST OF
A HARVARD TO VALPARAISO LINE. WITHIN THIS CHANNEL OF PRECIP...THE
BEST FORCING CONTINUES TO BE ALONG A ROCKFORD TO PONTIAC. HI-RES LCL
WRF AND RAP13 HAVE INDICATED A SIMILAR FORECAST. EXPECT THE FORCING
TO BE RATHER MODEST JUST AFTER ONSET OF PRECIP...WHICH SHOULD ALLOW
FOR POSSIBLY A PERIOD OF MODERATE OR A BRIEF HEAVY BURST OF SNOW.
THIS COULD RESULT IN RATES ARND 0.75-1"/HR...HOWEVER IT DOES NOT
APPEAR THIS WOULD OCCUR FOR ANY PROLONGED PERIOD OF TIME. SFC TEMPS
SHOULD REMAIN COOL ENOUGH THAT ALMOST ALL PRECIP WILL FALL AS SNOW.
TOTAL QPF WITH THIS EVENT HAVE HOVERED ARND 0.10" TO JUST UNDER
THIS...AGAIN THE HIGHEST QPF IS FOCUSED ALONG THE MAIN AXIS.
SNOWFALL ACCUMS WILL GENERALLY BE 1" OR LESS...WITH THE EXCEPTION OF
AREAS WEST/SOUTHWEST OF ROCKFORD THAT COULD PICK UP ARND 1-2". ALL
PRECIP WILL QUICKLY COME TO AN END THIS AFTN FROM NORTHWEST TO
SOUTHEAST.
WITH CONSIDERABLE CLOUD COVER EXPECTED FOR THE BULK OF THE
DAY...TEMPS MAY ONLY WARM INTO THE MID 30S.
OVERNIGHT WEAK DIFFLUENT FLOW SLIDES OVERHEAD AND SHOULD FROM SOME
THINNING OF THE CLOUD SHIELD. OTHERWISE THE OVERNIGHT PERIOD APPEARS
TO BE DRY WITH TEMPS COOLING INTO THE MID/UPR 20S.
CONFIDENCE IN TIMING OF SNOW...HIGH.
CONFIDENCE IN SNOWFALL TOTALS...MEDIUM.
CONFIDENCE IN TEMPERATURES...HIGH.
FRIDAY THROUGH WEDNESDAY...
ENSEMBLES HAVE MAINTAINED A RELATIVELY DECENT AGREEMENT...WITH
MINIMAL SPREAD BEING DEMONSTRATED WITH THE CURRENT FORECAST CYCLE. A
TREND OF LATE HAS BEEN FOR WEAKENING IN THE HEIGHT FIELDS OVER THE
GREAT LAKES REGION IN THE SUN-TUE TIMEFRAME...POSSIBLY SUGGESTING
SOME WEAK TROUGHING MAY DEVELOP AND KEEP THE REGION IN A WEAK
NORTHWEST FLOW. A ROBUST 500MB VORT OVER HUDSON BAY CONTINUES TO BE
A FOCUS OF CONCERN IN THE EXTENDED PERIODS...WHICH COULD SEND A FEW
LOBES OR VORTICITY/SHORTWAVES AROUND THE WESTERN PERIPHERY INTO THE
GREAT LAKES REGION. WITH A WEAKENING PAC-NW 500MB RIDGE...THE
PROBABILITY OF A FEW WEAK WAVES SLIDING ACROSS THE CWFA LOOKS
PROBABLE. THE TIMING OF SUCH AN EVENT IS DIFFICULT GIVEN THE FLUID
NATURE OF THE ENVIRONMENT.
AT THE ONSET OF THE EXTENDED IT APPEARS A SHORTWAVE DOES DEVELOP
ACROSS THE CENTRAL PLAINS AND SLIDE EAST...WITH A BNDRY SAGGING
SOUTH ACROSS THE UPPER MIDWEST/GREAT LAKES. SOUTHERLY FLOW SHOULD
AID IN ADVECTING WARMER AIR INTO THE CWFA...AND PUSH SFC TEMPS INTO
THE MID/UPR 40S OR POSSIBLY THE LOW 50S FOR THE SOUTHERN CWFA FRI.
LATEST SREF SOLUTION HAS INCREASED THE CONFIDENCE IN PRECIP...THUS
HAVE PUSHED POPS TO CATEGORICAL FRI AFTN. THIS WAVE THEN SLIDES
EAST...HOWEVER HAVE OPTED TO HOLD ONTO LIKELY POPS FRI EVE...AS IT
APPEARS THE ATMOSPHERE WILL LACK A MECHANISM TO COMPLETELY LOSE THE
PRECIP. EXPECT THE BULK OF THE PRECIP TO FALL AS RAIN...HOWEVER SOME
SNOW MAY BEGIN TO MIX IN ACROSS THE FAR NORTHERN CWFA OVERNIGHT INTO
EARLY SAT.
THEN WEAK ANTI-CYCLONIC FLOW ARRIVES SAT...HOWEVER THIS TOO APPEARS
TO BE SHORT-LIVED AS YET ANOTHER SYSTEM IS PROGGED TO ARRIVE
SUN/MON. THIS SYSTEM EARLY NEXT WEEK CONTINUES TO FAVOR A PATH FROM
THE CENTRAL PLAINS TOWARDS THE UPPER MIDWEST. SOUTHERLY FLOW WILL
ALLOW GULF MOISTURE TO FEED INTO THIS FEATURE...ENHANCING THE QPF
TOTALS. AT THIS TIME THIS FEATURE APPEARS TO BRING RAIN TO THE
AREA...POSSIBLY MIXED WITH SNOW DURING THE OVERNIGHT HOURS. THEN
ENSEMBLE PROG A BROAD ANTI-CYCLONIC FLOW TO DIVE SOUTHEAST FROM THE
CANADIAN ROCKIES INTO THE CENTRAL CONUS TUE. TEMPS WILL CONTINUE TO
BE SUB-SEASONAL TUE. BEYOND TUE IT APPEARS THE FLOW REMAINS
RELATIVELY FLAT...WHICH WILL ALLOW TEMPS TO SLOWLY RETURN TO
SEASONAL CONDS.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* TIMING AND DURATION OF BRIEF LIGHT SNOW EVENT BY EARLY AFTERNOON.
* LOWERING OF CIGS AND VSBYS WITH AFOREMENTIONED LIGHT SNOW.
ILX
//DISCUSSION...UPDATED 12Z...
A FAST MOVING CLIPPER TYPE SYSTEM REMAINS ON TRACK TO BRING AN
AREA OF SNOW STREAKING SOUTHEAST ACROSS NORTH CENTRAL TO EAST
CENTRAL ILLINOIS FROM MID-LATE MORNING INTO THE MID AFTERNOON
TODAY. ORD AND MDW WILL BE ON THE EASTERN PERIPHERY OF THIS
PRECIPITATION AREA WITH SOME QUESTION AS TO BOTH THE DURATION AND
INTENSITY OF ANY SNOWFALL AT THE AIRFIELDS... WITH THE BETTER SNOW
CHANCES REMAINING TO THE WEST. A SLIGHT SHIFT EASTWARD OF THE SNOW
BAND COULD RESULT IN A LONGER PERIOD OF SNOW AS WELL AS LOWER
VISIBILITY RESTRICTION AND GREATER ACCUMULATION. CURRENTLY THE
BEST FORECAST REMAINS IS FOR A BRIEF DURATION LIGHT SNOW OR FLURRY
LASTING A COUPLE OF HOURS WITH ONLY MARGINALLY RESTRICTED
VISIBILITY AND LITTLE TO NO ACCUMULATION AT ORD AND MDW. THE BEST
WINDOW FOR THIS TO HAPPEN REMAINS AROUND AND EITHER SIDE OF
18-19Z.
CIGS AROUND 10K FT SPREADING SOUTH AND EAST WILL GRADUALLY LOWER
THIS MORNING HOWEVER ANY CIG BLO 4500 FT AT ORD OR MDW IS
EXPECTED TO LAST ONLY A COUPLE OF HOURS... BARING ANY EASTWARD
SHIFT IN THE PRECIPITATION AREA. POINTS WESTWARD FROM ORD/MDW...
INCLUDING ROCKFORD... ARE EXPECTED TO SEE A GREATER BURST OF SNOW
BOTH IN DURATION AND INTENSITY... WITH A LONGER PERIOD OF LOWERED
CIGS AND VSBYS... AS WELL AS A MINOR ACCUMULATION (I.E. UP TO
AROUND AN INCH).
WINDS WILL REMAIN GENERALLY LESS THAN 10 KTS THROUGHOUT THE
DAY... BEGINNING WESTERLY AND TURNING MORE SOUTHERLY THIS
MORNING... AND THEN VEERING BACK SOUTHWEST THIS EVENING.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* MEDIUM TO HIGH CONFIDENCE IN GOING EXPECTATIONS OF TIMING AND
DURATION OF LIGHT SNOW...AND ASSOCIATED RESTRICTIONS OF
VISIBILITY AND LOWERING OF CIGS BRIEFLY TO MVFR AT TIMES THIS
AFTERNOON.
* HIGH CONFIDENCE IN WIND DIRECTION FORECASTS AND WIND SPEEDS
REMAINING GENERALLY LESS THAN 10 KTS THROUGHOUT THE DAY AS WSW
WINDS TURN SSW.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR WITH RN LIKELY DURING THE EVENING... CHANCE
-RASN OVERNIGHT.
SATURDAY...VFR. CHANCE OF MORNING FLURRIES.
SUNDAY...VFR. FAIR.
MONDAY...VFR. CHANCE -RASN.
TUESDAY...VFR.
WEDNESDAY...VFR.
ED F
&&
.MARINE...
314 AM CDT
WINDS WILL CONTINUE TO SLACKEN THIS MORNING ACROSS LAKE MICHIGAN
AS STRONG LOW PRESSURE MOVES OFF TO THE EAST THROUGH THE CANADIAN
MARITIME AND WEAK HIGH PRESSURE SETTLES IN ACROSS THE NORTHERN
GREAT LAKES. MEANWHILE... A CLIPPER TYPE LOW PRESSURE AREA WILL
STREAK QUICKLY SOUTHEAST FROM THE EASTERN DAKOTAS TO MISSOURI
TODAY. AS THIS LOW MOVES FARTHER SOUTHEAST AND WEAKENS THIS
EVENING... WEAK HIGH PRESSURE WILL BUILD SOUTHWARD ACROSS LAKE
MICHIGAN.
STRONG HIGH PRESSURE OVER THE NORTHERN PRAIRIE PROVINCES WILL THEN DRIVE
A COLD FRONT SOUTHWARD INTO NORTHERN LAKE MICHIGAN BY DAYBREAK
FRIDAY. THIS FRONT WILL CONTINUE TO MOVE SOUTH REACHING THE SOUTH
END OF LAKE MICHIGAN FRIDAY EVENING AS LOW PRESSURE THEN FORMS
ALONG THE FRONT AND MOVES EAST INTO NORTHERN ILLINOIS FRIDAY
NIGHT. FOLLOWING A PERIOD OF PREVAILING HIGH PRESSURE ACROSS LAKE
MICHIGAN LATER SATURDAY INTO SUNDAY... A STRONG LOW PRESSURE
SYSTEM WILL ORGANIZE IN THE LEE OF THE ROCKY MOUNTAINS AND MOVE
EAST INTO THE UPPER GREAT LAKES MONDAY NIGHT INTO TUESDAY. THIS
LOW MAY BRING A PERIOD OF GALE FORCE WINDS TO THE LAKE MONDAY
NIGHT AND TUESDAY.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
758 AM CDT THU MAR 14 2013
.DISCUSSION...
758 AM CDT
JUST A QUICK BLURB AS SOME PERIODIC HEAVY SNOWFALL RATES CONTINUE
TO BE OBSERVED UPSTREAM...WITH EVEN A COUPLE CG LIGHTNING STRIKES
ACROSS NC IOWA. MPX AND DVN SOUNDINGS INDICATE STEEP LAPSE
RATES...WITH THE RAP EVEN ANALYZING THESE RATES TOWARD 8 C/KM IN
THE MID-LEVELS ATOP WHERE THE STRIKES OCCURRED. SHORT TERM GUIDANCE
ADVECTS THIS WITH THE SHORT WAVE ACROSS THE FAR WESTERN FORECAST
AREA /ROCKFORD TO OTTAWA TO GIBSON CITY AND WEST/ BETWEEN 16Z AND
20Z. SO IN THAT PERIOD THERE COULD BE A FEW BURSTS OF HALF MILE
VISIBILITY TYPE SNOW...WHICH COULD LEAD TO UP TO AN INCH OF
ACCUMULATION EVEN WITH TEMPS LIKELY HOVERING AROUND FREEZING AT
THAT TIME.
MTF
&&
.PREV DISCUSSION...
334 AM CDT
TODAY AND TONIGHT...
FORECAST CHALLENGE FOR THE DAY CONTINUES TO FOCUS ON THE PRECIP
TIMING AND INTENSITY OF THE CLIPPER SYSTEM...THAT SHOULD ARRIVE JUST
AFTER DAYBREAK ACROSS THE FAR NORTHWEST PORTIONS OF THE CWFA.
IR IMAGERY EARLY THIS MORNING CONTINUES TO SHOW MINIMAL CLOUD COVER
ACROSS THE CWFA AS THE WEAK ANTI-CYCLONIC FLOW THAT BROUGHT MOSTLY
SUNNY SKIES WEDNESDAY STEADILY RETREATS SOUTH. DESPITE MOSTLY CLEAR
SKIES FOR A PERIOD OF TIME...TEMPS HAVE ONLY RADIATED INTO THE
LOW/MID 20S WHILE SUBSIDENCE HAS ALLOWED DEW PTS TO PUSH INTO THE
MID TEENS. CIRRUS CLOUDS EARLY THIS MORNING ARE BEGINNING TO ARRIVE
ACROSS THE WESTERN COUNTIES OF IL...AS THE LEADING EDGE OF THE
CLIPPER SYSTEM APPROACHES. THIS CIRRUS SHIELD WILL ARRIVE ACROSS THE
REMAINDER OF THE CWFA ARND DAYBREAK.
UPSTREAM THE CLIPPER SYSTEM THAT HAS BEEN PROGGED FOR SEVERAL
DAYS...HAS PUSHED INTO THE UPPER MIDWEST EARLY THIS MORNING. SFC
OBSERVATIONS UNDERNEATH THE CLOUD SHIELD AND WHERE IT IS
PRECIPITATING...HAVE SUGGESTED ONSET OF PRECIP TO BE ABRUPT. OBS
HAVE GONE FROM NO SNOW TO LGT/MOD SNOW WITHIN MINUTES OF
ARRIVAL...AND VSBYS HAVE QUICKLY BEEN REDUCED TO ARND 1SM. WHEN THIS
SYSTEM WAS OVER NORTH DAKOTA OBS WERE SLIGHTLY LOWER WITH VSBYS ARND
1/2SM. CLOUD TOPS APPEAR TO BE COOLING WITH THE LATEST SCANS...AND
THIS INDICATES SOME STRENGTHENING MIGHT BE TAKING PLACE THE FURTHER
SOUTHEAST THE SYSTEM SLIDES.
GUIDANCE HAS BACKED OFF ON THE INTENSITY AND COVERAGE OF THE PRECIP
WITH THE SYSTEM TODAY...POSSIBLY A BY-PRODUCT OF THE LACK OF LLVL
MOISTURE AND HOW QUICKLY SATURATION TAKES PLACE. TIMING STILL LOOKS
GOOD WITH AN ARRIVAL ACROSS THE FAR NW CWFA ARND 14-15Z...STREAMING
SE FROM ROCKFORD/STERLING TO KANKAKEE/PAXTON BY 16-18Z.
THE DGZ REMAINS CONSISTENT ARND 10KFT AGL...WITH A GOOD SLUG OF LIFT
INTO THE CORE OF THE BEST GROWTH ZONE AT 15 TO 17Z...MAINLY WEST OF
A HARVARD TO VALPARAISO LINE. WITHIN THIS CHANNEL OF PRECIP...THE
BEST FORCING CONTINUES TO BE ALONG A ROCKFORD TO PONTIAC. HI-RES LCL
WRF AND RAP13 HAVE INDICATED A SIMILAR FORECAST. EXPECT THE FORCING
TO BE RATHER MODEST JUST AFTER ONSET OF PRECIP...WHICH SHOULD ALLOW
FOR POSSIBLY A PERIOD OF MODERATE OR A BRIEF HEAVY BURST OF SNOW.
THIS COULD RESULT IN RATES ARND 0.75-1"/HR...HOWEVER IT DOES NOT
APPEAR THIS WOULD OCCUR FOR ANY PROLONGED PERIOD OF TIME. SFC TEMPS
SHOULD REMAIN COOL ENOUGH THAT ALMOST ALL PRECIP WILL FALL AS SNOW.
TOTAL QPF WITH THIS EVENT HAVE HOVERED ARND 0.10" TO JUST UNDER
THIS...AGAIN THE HIGHEST QPF IS FOCUSED ALONG THE MAIN AXIS.
SNOWFALL ACCUMS WILL GENERALLY BE 1" OR LESS...WITH THE EXCEPTION OF
AREAS WEST/SOUTHWEST OF ROCKFORD THAT COULD PICK UP ARND 1-2". ALL
PRECIP WILL QUICKLY COME TO AN END THIS AFTN FROM NORTHWEST TO
SOUTHEAST.
WITH CONSIDERABLE CLOUD COVER EXPECTED FOR THE BULK OF THE
DAY...TEMPS MAY ONLY WARM INTO THE MID 30S.
OVERNIGHT WEAK DIFFLUENT FLOW SLIDES OVERHEAD AND SHOULD FROM SOME
THINNING OF THE CLOUD SHIELD. OTHERWISE THE OVERNIGHT PERIOD APPEARS
TO BE DRY WITH TEMPS COOLING INTO THE MID/UPR 20S.
CONFIDENCE IN TIMING OF SNOW...HIGH.
CONFIDENCE IN SNOWFALL TOTALS...MEDIUM.
CONFIDENCE IN TEMPERATURES...HIGH.
FRIDAY THROUGH WEDNESDAY...
ENSEMBLES HAVE MAINTAINED A RELATIVELY DECENT AGREEMENT...WITH
MINIMAL SPREAD BEING DEMONSTRATED WITH THE CURRENT FORECAST CYCLE. A
TREND OF LATE HAS BEEN FOR WEAKENING IN THE HEIGHT FIELDS OVER THE
GREAT LAKES REGION IN THE SUN-TUE TIMEFRAME...POSSIBLY SUGGESTING
SOME WEAK TROUGHING MAY DEVELOP AND KEEP THE REGION IN A WEAK
NORTHWEST FLOW. A ROBUST 500MB VORT OVER HUDSON BAY CONTINUES TO BE
A FOCUS OF CONCERN IN THE EXTENDED PERIODS...WHICH COULD SEND A FEW
LOBES OR VORTICITY/SHORTWAVES AROUND THE WESTERN PERIPHERY INTO THE
GREAT LAKES REGION. WITH A WEAKENING PAC-NW 500MB RIDGE...THE
PROBABILITY OF A FEW WEAK WAVES SLIDING ACROSS THE CWFA LOOKS
PROBABLE. THE TIMING OF SUCH AN EVENT IS DIFFICULT GIVEN THE FLUID
NATURE OF THE ENVIRONMENT.
AT THE ONSET OF THE EXTENDED IT APPEARS A SHORTWAVE DOES DEVELOP
ACROSS THE CENTRAL PLAINS AND SLIDE EAST...WITH A BNDRY SAGGING
SOUTH ACROSS THE UPPER MIDWEST/GREAT LAKES. SOUTHERLY FLOW SHOULD
AID IN ADVECTING WARMER AIR INTO THE CWFA...AND PUSH SFC TEMPS INTO
THE MID/UPR 40S OR POSSIBLY THE LOW 50S FOR THE SOUTHERN CWFA FRI.
LATEST SREF SOLUTION HAS INCREASED THE CONFIDENCE IN PRECIP...THUS
HAVE PUSHED POPS TO CATEGORICAL FRI AFTN. THIS WAVE THEN SLIDES
EAST...HOWEVER HAVE OPTED TO HOLD ONTO LIKELY POPS FRI EVE...AS IT
APPEARS THE ATMOSPHERE WILL LACK A MECHANISM TO COMPLETELY LOSE THE
PRECIP. EXPECT THE BULK OF THE PRECIP TO FALL AS RAIN...HOWEVER SOME
SNOW MAY BEGIN TO MIX IN ACROSS THE FAR NORTHERN CWFA OVERNIGHT INTO
EARLY SAT.
THEN WEAK ANTI-CYCLONIC FLOW ARRIVES SAT...HOWEVER THIS TOO APPEARS
TO BE SHORT-LIVED AS YET ANOTHER SYSTEM IS PROGGED TO ARRIVE
SUN/MON. THIS SYSTEM EARLY NEXT WEEK CONTINUES TO FAVOR A PATH FROM
THE CENTRAL PLAINS TOWARDS THE UPPER MIDWEST. SOUTHERLY FLOW WILL
ALLOW GULF MOISTURE TO FEED INTO THIS FEATURE...ENHANCING THE QPF
TOTALS. AT THIS TIME THIS FEATURE APPEARS TO BRING RAIN TO THE
AREA...POSSIBLY MIXED WITH SNOW DURING THE OVERNIGHT HOURS. THEN
ENSEMBLE PROG A BROAD ANTI-CYCLONIC FLOW TO DIVE SOUTHEAST FROM THE
CANADIAN ROCKIES INTO THE CENTRAL CONUS TUE. TEMPS WILL CONTINUE TO
BE SUB-SEASONAL TUE. BEYOND TUE IT APPEARS THE FLOW REMAINS
RELATIVELY FLAT...WHICH WILL ALLOW TEMPS TO SLOWLY RETURN TO
SEASONAL CONDS.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* TIMING AND DURATION OF BRIEF LIGHT SNOW EVENT AROUND THE MIDDAY
TO EARLY AFTERNOON.
* LOWERING OF CIGS AND VSBYS WITH AFOREMENTIONED SNOW.
ED F
//DISCUSSION...UPDATED 12Z...
A FAST MOVING CLIPPER TYPE SYSTEM REMAINS ON TRACK TO BRING AN
AREA OF SNOW STREAKING SOUTHEAST ACROSS NORTH CENTRAL TO EAST
CENTRAL ILLINOIS FROM MID-LATE MORNING INTO THE MID AFTERNOON
TODAY. ORD AND MDW WILL BE ON THE EASTERN PERIPHERY OF THIS
PRECIPITATION AREA WITH SOME QUESTION AS TO BOTH THE DURATION AND
INTENSITY OF ANY SNOWFALL AT THE AIRFIELDS... WITH THE BETTER SNOW
CHANCES REMAINING TO THE WEST. A SLIGHT SHIFT EASTWARD OF THE SNOW
BAND COULD RESULT IN A LONGER PERIOD OF SNOW AS WELL AS LOWER
VISIBILITY RESTRICTION AND GREATER ACCUMULATION. CURRENTLY THE
BEST FORECAST REMAINS IS FOR A BRIEF DURATION LIGHT SNOW OR FLURRY
LASTING A COUPLE OF HOURS WITH ONLY MARGINALLY RESTRICTED
VISIBILITY AND LITTLE TO NO ACCUMULATION AT ORD AND MDW. THE BEST
WINDOW FOR THIS TO HAPPEN REMAINS AROUND AND EITHER SIDE OF
18-19Z.
CIGS AROUND 10K FT SPREADING SOUTH AND EAST WILL GRADUALLY LOWER
THIS MORNING HOWEVER ANY CIG BLO 4500 FT AT ORD OR MDW IS
EXPECTED TO LAST ONLY A COUPLE OF HOURS... BARING ANY EASTWARD
SHIFT IN THE PRECIPITATION AREA. POINTS WESTWARD FROM ORD/MDW...
INCLUDING ROCKFORD... ARE EXPECTED TO SEE A GREATER BURST OF SNOW
BOTH IN DURATION AND INTENSITY... WITH A LONGER PERIOD OF LOWERED
CIGS AND VSBYS... AS WELL AS A MINOR ACCUMULATION (I.E. UP TO
AROUND AN INCH).
WINDS WILL REMAIN GENERALLY LESS THAN 10 KTS THROUGHOUT THE
DAY... BEGINNING WESTERLY AND TURNING MORE SOUTHERLY THIS
MORNING... AND THEN VEERING BACK SOUTHWEST THIS EVENING.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN GOING EXPECTATIONS OF TIMING AND DURATION
OF LIGHT SNOW... AND ASSOCIATED RESTRICTIONS OF VISIBILITY AND
LOWERING OF CIGS.
* HIGH CONFIDENCE IN WIND DIRECTION FORECASTS AND WIND SPEEDS REMAINING
GENERALLY LESS THAN 10 KTS THROUGHOUT THE DAY.
ED F
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...MVFR WITH RN LIKELY DURING THE EVENING... CHANCE
-RASN OVERNIGHT.
SATURDAY...VFR. CHANCE OF MORNING FLURRIES.
SUNDAY...VFR. FAIR.
MONDAY...VFR. CHANCE -RASN.
TUESDAY...VFR.
WEDNESDAY...VFR.
ED F
&&
.MARINE...
314 AM CDT
WINDS WILL CONTINUE TO SLACKEN THIS MORNING ACROSS LAKE MICHIGAN
AS STRONG LOW PRESSURE MOVES OFF TO THE EAST THROUGH THE CANADIAN
MARITIME AND WEAK HIGH PRESSURE SETTLES IN ACROSS THE NORTHERN
GREAT LAKES. MEANWHILE... A CLIPPER TYPE LOW PRESSURE AREA WILL
STREAK QUICKLY SOUTHEAST FROM THE EASTERN DAKOTAS TO MISSOURI
TODAY. AS THIS LOW MOVES FARTHER SOUTHEAST AND WEAKENS THIS
EVENING... WEAK HIGH PRESSURE WILL BUILD SOUTHWARD ACROSS LAKE
MICHIGAN.
STRONG HIGH PRESSURE OVER THE NORTHERN PRAIRIE PROVINCES WILL THEN DRIVE
A COLD FRONT SOUTHWARD INTO NORTHERN LAKE MICHIGAN BY DAYBREAK
FRIDAY. THIS FRONT WILL CONTINUE TO MOVE SOUTH REACHING THE SOUTH
END OF LAKE MICHIGAN FRIDAY EVENING AS LOW PRESSURE THEN FORMS
ALONG THE FRONT AND MOVES EAST INTO NORTHERN ILLINOIS FRIDAY
NIGHT. FOLLOWING A PERIOD OF PREVAILING HIGH PRESSURE ACROSS LAKE
MICHIGAN LATER SATURDAY INTO SUNDAY... A STRONG LOW PRESSURE
SYSTEM WILL ORGANIZE IN THE LEE OF THE ROCKY MOUNTAINS AND MOVE
EAST INTO THE UPPER GREAT LAKES MONDAY NIGHT INTO TUESDAY. THIS
LOW MAY BRING A PERIOD OF GALE FORCE WINDS TO THE LAKE MONDAY
NIGHT AND TUESDAY.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1045 AM CDT THU MAR 14 2013
...UPDATE TO SYNOPSIS AND CLIMATE SECTIONS...
.SYNOPSIS...
ISSUED AT 1045 AM CDT THU MAR 14 2013
THE 12Z PI 250 HPA RAOB MAP SHOWED NORTHWESTERLY 55 KT FLOW OVER KDDC.
THE STRONGEST JET WINDS OBSERVED ACROSS PORTIONS OF THE RAOB NETWORK
WAS LOCATED ACROSS NORTHERN FLORIDA WITH WINDS AT 150 KT FROM THE WEST-
SOUTHWEST. THE 500 HPA GEOPOTENTIAL HEIGHT PATTERN SHOWED A BROAD RIDGE
ACROSS THE WESTERN U.S. AND AN AMPLIFIED TROF ACROSS THE NORTHEAST AND
INTO PORTIONS OF QUEBEC. SOME MID LEVEL MOISTURE WAS MOVING ACROSS THE
TOP OF THE RIDGE AXIS FROM THE PACNW TO THE NORTHERN ROCKIES. AT 700/850
HPA, WARMING WAS NOTED AT KDDC WITH TEMPS AT 0C AND 14C, RESPECTIVELY.
AT THE SURFACE, A FRAGMENTED TROF AXIS WAS ANALYZED ACROSS KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 220 AM CDT THU MAR 14 2013
TRANQUIL WEATHER IS ANTICIPATED THROUGHOUT THE SHORT TERM PERIOD AS
NORTHWEST FLOW ALOFT SUPPRESSES ANY SIGNIFICANT WEATHER FEATURES
FROM FORMING. ONLY HIGH CLOUDS WILL BE OBSERVED TODAY THROUGH
TOMORROW MORNING. AS FOR WINDS, A WEAK SURFACE TROUGH WILL MOVE
THROUGH WESTERN KANSAS EARLY THIS MORNING SHIFTING WINDS TO THE
NORTHWEST BY THIS AFTERNOON. THIS WILL BE SHORT LIVED AS AN AXIS OF
A RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION THIS EVENING
ALLOWING WINDS TO BECOME LIGHT AN VARIABLE. A SECOND SURFACE TROUGH
THEN DEVELOPS ACROSS EASTERN COLORADO OVERNIGHT TONIGHT SHIFTING
WINDS BACK TO THE SOUTHWEST BY TOMORROW MORNING. ABOVE NORMAL
TEMPERATURES ARE FORECASTED TODAY INTO TOMORROW AS 850 TEMPERATURES
RISE INTO THE MID TO UPPER TEENS. THIS IN CONJUNCTION WITH THE
DOWNSLOPE WINDS AT THE SURFACE WILL ALLOW HIGHS TODAY TO RANGE FROM
AROUND 70 ACROSS THE I-70 CORRIDOR TO UPPER 70S ACROSS PARTS OF THE
KS/OK BORDER. LOWS BY TOMORROW MORNING ARE FORECASTED TO RANGE FROM
THE UPPER 30S ACROSS THE KS/CO BORDER TO LOWER 40S ACROSS CENTRAL
AND SOUTH CENTRAL KANSAS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 AM CDT THU MAR 14 2013
UPPER LEVEL RIDGE AXIS LOCATED ACROSS THE WESTERN UNITED STATES LATE
WEEK WILL WEAKEN AS AN UPPER LEVEL JET STREAK MOVES ACROSS IDAHO AND
MONTANA. AS THIS UPPER LEVEL JET MOVES OUT INTO THE NORTHERN PLAINS
FRIDAY AFTERNOON, A COLD FRONT WILL DROP SOUTH INTO NORTHERN KANSAS
BY LATE DAY. SOUTH OF THE COLD FRONT THE NAM, GFS, AND ECMWF WERE
ALL IN DECENT AGREEMENT WITH THE 850MB TEMPERATURES AT 00Z SATURDAY
ACROSS SOUTHWEST KANSAS RANGING FROM 20C TO NEAR 25C. BASED ON THIS
THE PREVIOUS FORECAST WITH AFTERNOON HIGHS IN THE UPPER 70S TO LOWER
80S STILL APPEARS ON TRACK. CONSMOS AND MOSGUIDE ALSO SUPPORTING
SIMILAR HIGHS ALSO.
BY 12Z SATURDAY THIS FRONT IS FORECAST TO BE LOCATED ACROSS OKLAHOMA
AND THE TEXAS PANHANDLE AS AN EASTERLY UPSLOPE FLOW DEVELOPS NEAR
THE SURFACE ACROSS WESTERN KANSAS. IN ADDITION 850-700MB WARM AIR
ADVECTION AND MOISTURE WILL BE IMPROVING THROUGH SATURDAY NIGHT.
925MB TO 850MB TEMPERATURE PROFILES SUGGESTS ANY PRECIPITATION THAT
DOES DEVELOP WILL BE IN LIQUID FORM EARLY THIS WEEKEND, HOWEVER A
REINFORCEMENT OF COLDER AIR IS EXPECTED TO INVADE POTIONS OF NORTH
CENTRAL KANSAS LATE SUNDAY AS AN UPPER LEVEL TROUGH MOVES ACROSS THE
NORTHERN PLAINS. QUICK LOOK AT SOUNDINGS SUNDAY NIGHT STILL SUPPORTS
MAINLY RAIN BUT WILL NEED TO MONITOR THE MAGNITUDE OF THE COLD AIR
INVADING THE I-70 CORRIDOR SUNDAY NIGHT. A PERIOD OF LIGHT SNOW MAY
BE POSSIBLE IF THE COLDER ECMWF VERIFIES.
HIGH PRESSURE AT THE SURFACE WILL BUILD ACROSS THE PLAINS EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE MOVES EAST ACROSS THE WESTERN UNITED
STATES. DOWNSLOPE FLOW WILL BE DEVELOPING IN WESTERN KANSAS AND SOME
COOLER AIR WILL BE RECIRCULATING AROUND THE SURFACE HIGHS IN CENTRAL
KANSAS. THIS WILL RESULT IN A GRADIENT OF TEMPERATURES ACROSS
SOUTHWEST KANSAS THROUGH MID WEEK. AT THIS TIME BASED ON THE
925-850MB WARMING TREND SUGGESTED BY THE GFS AND ECMWF EARLY NEXT
WEEK THE HIGHS REBOUNDING BACK INTO THE 60S BY TUESDAY STILL LOOKS
REASONABLE ACROSS FAR WESTERN KANSAS. A FEW LOWER 70S ARE NOT OUT OF
THE QUESTION IN FAR SOUTHWEST KANSAS BY WEDNESDAY. FURTHER EAST AM A
LITTLE CONCERNED ABOUT HOW QUICKLY THE TEMPERATURES WILL REBOUND
ACROSS SOUTH CENTRAL AND NORTH CENTRAL KANSAS. AT THIS TIME HAVE
DECIDED TO STAY CLOSE TO THE CREXTENDFCST_INIT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 606 AM CDT THU MAR 14 2013
THE NAM AND HRRR WERE IN DECENT AGREEMENT IN MOVING A SURFACE
BOUNDARY ACROSS WESTERN KANSAS EARLY THIS MORNING. AS THIS
BOUNDARY PASSES A NORTHWEST WIND WILL DEVELOP. NORTHWEST WINDS AT
AROUND 10KTS WILL THEN BECOME LIGHT AND VARIABLE BY 00Z FRIDAY.
BASED ON BUFR SOUNDINGS VFR CONDITIONS ARE EXPECTED TO CONTINUE
FOR THE NEXT 24 HOURS.
&&
.FIRE WEATHER...
ISSUED AT 320 AM CDT THU MAR 14 2013
ON FRIDAY THE AFTERNOON RELATIVE HUMIDITIES WILL FALL BACK INTO THE
10 TO 15 PERCENT RANGE ACROSS POTIONS OF WESTERN KANSAS. SUSTAINED
WIND SPEEDS FRIDAY AFTERNOON HOWEVER ARE EXPECTED TO AVERAGE BETWEEN
10 TO 15 MPH. ALTHOUGH CRITICAL FIRE WEATHER CONDITIONS ARE NOT
EXPECTED...GIVEN THE LOW RELATIVE HUMIDITIES FRIDAY AFTERNOON THIS
WILL RESULT IN ELEVATED FIRE WEATHER CONCERNS ALONG AND WEST OF
HIGHWAY 83.
&&
.CLIMATE...
ISSUED AT 1045 AM CDT THU MAR 14 2013
THERE IS THE POTENTIAL FOR RECORDS MAXIMUMS TO BE SMASHED TOMORROW.
SEE THE PUBLIC INFORMATION STATEMENT (TOPPNSDDC) FOR SPECIFIC RECORD
VALUES FOR FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 74 41 82 43 / 0 0 0 0
GCK 74 40 82 42 / 0 0 0 0
EHA 74 40 83 43 / 0 0 0 0
LBL 76 40 83 43 / 0 0 0 0
HYS 70 41 80 40 / 0 0 0 0
P28 74 42 83 45 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...HOVORKA_42
LONG TERM...BURGERT
AVIATION...BURGERT
FIRE WEATHER...BURGERT
CLIMATE...WFODDC
AREA FORECAST DISCUSSION
NWS GOODLAND KS
522 AM MDT THU MAR 14 2013
.SHORT TERM...(TODAY AND THURSDAY)
ISSUED AT 308 AM MDT THU MAR 14 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOWS LARGE SCALE TROUGH IN
PLACE ACROSS NEW ENGLAND AND A RIDGE CENTERED ACROSS THE SOUTHWEST
US. BETWEEN THESE FEATURES NW FLOW EXTENDS ACROSS THE NORTHERN AND
CENTRAL PLAINS. EMBEDDED WITHIN THE MEAN FLOW SEVERAL WEAK SHORTWAVE
TROUGHS ARE PRODUCING HIGH CLOUDS WHICH ARE QUICKLY STREAMING FROM
THE NW TO SE ACROSS THE CWA. SOUNDS ARE VERY DRY SO DESPITE PRESENCE
OF ELEVATED FORCING WE SHOULD CONTINUE TO SEE DRY CONDITIONS.
H5 RIDGE IN OVER THE SOUTHWEST US IS PROGGED TO FLATTED WITH NW FLOW
TRANSITIONING TO WESTERLY FLOW BY FRIDAY. BL FLOW WILL CONTINUE TO
BE WESTERLY/DOWNSLOPE TODAY WITH DRY/WARM AIRMASS EXPECTED TODAY AND
FRIDAY. H85 TEMPS ARE ADVERTISED TO BE 2-3C WARMER THAN WED AND ON
FRI ALMOST 5-10C WARMER. ACCOUNTING FOR SIMILAR BIAS WE COULD SEE
TEMPS IN THE LOW TO MID 70S FOR MOST LOCATIONS TODAY AND 80F OR
WARMER ON FRI. THE COMBINATION OF WARM TEMPS/VERY DRY
CONDITIONS...COMBINED WITH INCREASING WINDS FRI AFTERNOON COULD LEAD
TO DEVELOPMENT OF CRITICAL FIRE CONDITIONS. RIGHT NOW CALCULATED RH
VALUES RANGE FROM NEAR 10 PERCENT IN OUR SOUTHWEST TO AROUND 15
PERCENT IN THE NORTH. WITH UNIDIRECTIONAL WESTERLY FLOW AND
STRENGTHENING SURFACE TROUGH WE SHOULD SEE AT LEAST BREEZY
CONDITIONS DEVELOP FRI AFTERNOON THOUGH LOCATION/MAGNITUDE OF
STRONGEST GUSTS IS STILL IN QUESTION. LOWEST RH VALUES AND WINDS IN
HE 20-25MPH RANGE MAY NOT OVERLAP BUT IT COULD BE CLOSE. WILL NOT
ISSUE ANY FIRE WEATHER HIGHLIGHTS DURING THIS FORECAST CYCLE AND WILL
ALLOW SUBSEQUENT SHIFTS TO FINE TUNE.
A BACKDOOR COLD FRONT WILL DROP SOUTH OVER THE CWA BY SATURDAY. WEAK
ENERGY WITHIN MEAN W/NW FLOW AHEAD OF THIS FRONT AND ELEVATED
INSTABILITY COULD SUPPORT SHOWER DEVELOPMENT LATE FRIDAY NIGHT WITH
INCREASING COVERAGE WITH FROPA SAT AND APPROACHING SHORTWAVE TROUGH
OVER THE PAC NW SAT NIGHT. MOISTURE PROFILES REMAIN DRY BELOW 600MB
THROUGH SAT AND REALLY DO NO BEGIN TO COMPLETELY MOISTEN UNTIL
SATURDAY AFTERNOON/EVENING. MOISTURE ADVECTION IS ALSO FAIRLY
UNIMPRESSIVE AHEAD OF THIS FRONT WITH BETTER MOISTURE RETURN
GENERALLY IN THE SOUTH. I DECIDED AGAINST INCREASING POPS SAT/SAT
NIGHT BEYOND CHANCE CATEGORY AND LEANED TOWARDS THE LOWER END OF
GUIDANCE ON QPF WITH PRECIP THAT OCCURS EXPECTED TO BE ON LIGHTER
SIDE. WITH MOST GUIDANCE ON THE WARMER SIDE RAIN SHOWERS WILL
LIKELY BE FAVORED WITH ONLY A BRIEF RAIN/SNOW MIX POSSIBLE LATE
SAT NIGHT ASSUMING WE SEE EVAPORATIVE COOLING PROCESSES. I DOUBT
WE WOULD SEE MUCH SNOW ACCUMULATION SAT NIGHT IF WE DID
TRANSITION OVER WITH LIGHT PRECIP RATES AND WARM GROUND TEMPS
EXPECTED.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 308 AM MDT THU MAR 14 2013
MODELS HAVE COME INTO SOMEWHAT BETTER AGREEMENT WITH THE WEATHER
SYSTEM EXPECTED TO SWING ACROSS THE PLAINS SUNDAY EVENING INTO
MONDAY MORNING...HOWEVER QUESTIONS STILL LINGER WITH RESPECT TO
TEMPERATURES AND THUS WEATHER TYPES.
THE GFS...CANADIAN AND EUROPEAN MODELS ARE IN FAIRLY GOOD AGREEMENT
WITH RESPECT TO THE TIMING OF STRONG UPPER LEVEL SHORTWAVE AND
DEVELOPMENT OF A SURFACE LOW AS THE SHORTWAVE MOVES ACROSS THE
PLAINS. THE GFS MODEL STANDS OUT FROM THE CANADIAN AND EUROPEAN
MODELS IN THAT IT IS STILL FORECASTING MUCH WARMER TEMPERATURES
DURING THE AFTERNOON ON SUNDAY. THE EUROPEAN AND CANADIAN ARE
SUGGESTING A COOLER...MORE STABLE ATMOSPHERE WHICH WOULD LIMIT
INSTABILITY AND WOULD GIVE A BETTER CHANCE AT SOME WINTRY
PRECIPITATION EARLY ON SUNDAY MORNING. THEREFORE...FOR THE TIME
BEING A RAIN SNOW MIX HAS BEEN MENTIONED FOR ROUGHLY THE NORTHERN
HALF OF THE FORECAST AREA SUNDAY MORNING DUE TO TEMPERATURE
UNCERTAINTY. IF THE GFS PANS OUT...THERE WOULD BE A BETTER CHANCE OF
SOME THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT WILL MOVE
THROUGH SUNDAY EVENING. EITHER WAY...ALL THREE MODELS ARE
FORECASTING PRECIPITATION ALONG AND AHEAD OF THE COLD FRONT. THE
QUESTION THAT REMAINS IS WILL THERE BE THUNDERSTORMS AND THUS
HEAVIER PRECIPITATION AMOUNTS POSSIBLE. ANOTHER CAUSE FOR CONCERN IS
THAT THE CANADIAN AND EUROPEAN MODELS ARE SUGGESTING A WARM FRONT
WILL REMAIN OVER THE AREA THROUGHOUT THE DAY ON SUNDAY WITH
PRECIPITATION DEVELOPING ALONG THE FRONT. IF THIS WERE TO
OCCUR...THE POPS ARE UNDERDONE DURING THE DAY ON SUNDAY AND WOULD
NEED TO BE INCREASED IN LATER FORECAST CYCLES. ALL PRECIP DURING THE
DAYLIGHT HOURS ON SUNDAY SHOULD NOT BE FROZEN IN NATURE.
ONCE THE COLD FRONT PUSHES THROUGH SUNDAY NIGHT...PRECIPITATION
CHANCES WILL DECREASE. A BRIEF CHANGE TO SNOW IS FORECAST BEHIND THE
FRONT AS TEMPERATURES ALOFT COOL ENOUGH TO ALLOW SNOW TO REACH THE
GROUND WITHOUT MELTING. THE EUROPEAN MODEL IS ABOUT 6 HOURS SLOWER
THAN THE OTHER TWO MODELS. THIS WOULD MEAN A BETTER CHANCE FOR SNOW
BEHIND THE FRONT ACROSS MAINLY NORTHEAST PORTIONS OF THE FORECAST
AREA. TRIED TO REFLECT CHANCES OF PRECIPITATION DECREASING BEHIND
THE FRONT AFTER MIDNIGHT BASED ON MODEL GUIDANCE.
FOLLOWING THIS WEATHER SYSTEM...A RIDGE OF HIGH PRESSURE WILL BUILD
IN ACROSS THE ROCKIES...LEADING TO DRY WEATHER ACROSS THE HIGH
PLAINS SINCE ANY DISTURBANCES WILL STAY WELL TO THE NORTH. MODELS
ARE BEGINNING TO SUGGEST A LARGE LONGWAVE TROUGH DEVELOPING OVER THE
WESTERN UNITED STATES AND MOVING ACROSS THE CENTRAL PLAINS BY THE
MIDDLE TO END OF NEXT WEEK. UNFORTUNATELY THE GFS AND EUROPEAN
MODELS HAVE LARGE DIFFERENCES BETWEEN THEIR SOLUTIONS WITH THE GFS
ABOUT A DAY FASTER THAN THE EUROPEAN. THE CR INIT PROCEDURE
SUGGESTED LIKELY POPS BEGINNING THURSDAY NIGHT BUT HAVE CUT THOSE IN
HALF TO START DUE TO THE LARGE DIFFERENCES IN MODEL SOLUTIONS.
AS THE RIDGE BUILDS IN...WARMER WEATHER WILL AGAIN RETURN. HAVE
INCREASED TEMPERATURES SLIGHTLY AS THE PATTERN WILL BE FAVORABLE FOR
A WARMING TREND. TEMPERATURES SHOULD BE ABOVE NORMAL FROM THIS
TUESDAY ONWARD WITH NEAR NORMAL TEMPERATURES BEHIND THE COLD
FRONT THIS MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 522 AM MDT THU MAR 14 2013
VFR CONDITIONS WILL PREVAIL AT BOTH KGLD AND KMCK TERMINALS THROUGH
THE PERIOD. WESTERLY WINDS BELOW 12KT ARE EXPECTED TO PREVAIL
THROUGH THE TAF PERIOD. BY MIDDAY A SURFACE TROUGH WILL MOVE OVER
KMCK WITH WINDS GOING LIGHT AND VARIABLE...HOWEVER THEY SHOULD
VEER BACK TO THE SOUTHWEST LATER THIS AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
608 AM CDT THU MAR 14 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 220 AM CDT THU MAR 14 2013
TRANQUIL WEATHER IS ANTICIPATED THROUGHOUT THE SHORT TERM PERIOD AS
NORTHWEST FLOW ALOFT SUPPRESSES ANY SIGNIFICANT WEATHER FEATURES
FROM FORMING. ONLY HIGH CLOUDS WILL BE OBSERVED TODAY THROUGH
TOMORROW MORNING. AS FOR WINDS, A WEAK SURFACE TROUGH WILL MOVE
THROUGH WESTERN KANSAS EARLY THIS MORNING SHIFTING WINDS TO THE
NORTHWEST BY THIS AFTERNOON. THIS WILL BE SHORT LIVED AS AN AXIS OF
A RIDGE OF HIGH PRESSURE MOVES ACROSS THE REGION THIS EVENING
ALLOWING WINDS TO BECOME LIGHT AN VARIABLE. A SECOND SURFACE TROUGH
THEN DEVELOPS ACROSS EASTERN COLORADO OVERNIGHT TONIGHT SHIFTING
WINDS BACK TO THE SOUTHWEST BY TOMORROW MORNING. ABOVE NORMAL
TEMPERATURES ARE FORECASTED TODAY INTO TOMORROW AS 850 TEMPERATURES
RISE INTO THE MID TO UPPER TEENS. THIS IN CONJUNCTION WITH THE
DOWNSLOPE WINDS AT THE SURFACE WILL ALLOW HIGHS TODAY TO RANGE FROM
AROUND 70 ACROSS THE I-70 CORRIDOR TO UPPER 70S ACROSS PARTS OF THE
KS/OK BORDER. LOWS BY TOMORROW MORNING ARE FORECASTED TO RANGE FROM
THE UPPER 30S ACROSS THE KS/CO BORDER TO LOWER 40S ACROSS CENTRAL
AND SOUTH CENTRAL KANSAS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 AM CDT THU MAR 14 2013
UPPER LEVEL RIDGE AXIS LOCATED ACROSS THE WESTERN UNITED STATES LATE
WEEK WILL WEAKEN AS AN UPPER LEVEL JET STREAK MOVES ACROSS IDAHO AND
MONTANA. AS THIS UPPER LEVEL JET MOVES OUT INTO THE NORTHERN PLAINS
FRIDAY AFTERNOON, A COLD FRONT WILL DROP SOUTH INTO NORTHERN KANSAS
BY LATE DAY. SOUTH OF THE COLD FRONT THE NAM, GFS, AND ECMWF WERE
ALL IN DECENT AGREEMENT WITH THE 850MB TEMPERATURES AT 00Z SATURDAY
ACROSS SOUTHWEST KANSAS RANGING FROM 20C TO NEAR 25C. BASED ON THIS
THE PREVIOUS FORECAST WITH AFTERNOON HIGHS IN THE UPPER 70S TO LOWER
80S STILL APPEARS ON TRACK. CONSMOS AND MOSGUIDE ALSO SUPPORTING
SIMILAR HIGHS ALSO.
BY 12Z SATURDAY THIS FRONT IS FORECAST TO BE LOCATED ACROSS OKLAHOMA
AND THE TEXAS PANHANDLE AS AN EASTERLY UPSLOPE FLOW DEVELOPS NEAR
THE SURFACE ACROSS WESTERN KANSAS. IN ADDITION 850-700MB WARM AIR
ADVECTION AND MOISTURE WILL BE IMPROVING THROUGH SATURDAY NIGHT.
925MB TO 850MB TEMPERATURE PROFILES SUGGESTS ANY PRECIPITATION THAT
DOES DEVELOP WILL BE IN LIQUID FORM EARLY THIS WEEKEND, HOWEVER A
REINFORCEMENT OF COLDER AIR IS EXPECTED TO INVADE POTIONS OF NORTH
CENTRAL KANSAS LATE SUNDAY AS AN UPPER LEVEL TROUGH MOVES ACROSS THE
NORTHERN PLAINS. QUICK LOOK AT SOUNDINGS SUNDAY NIGHT STILL SUPPORTS
MAINLY RAIN BUT WILL NEED TO MONITOR THE MAGNITUDE OF THE COLD AIR
INVADING THE I-70 CORRIDOR SUNDAY NIGHT. A PERIOD OF LIGHT SNOW MAY
BE POSSIBLE IF THE COLDER ECMWF VERIFIES.
HIGH PRESSURE AT THE SURFACE WILL BUILD ACROSS THE PLAINS EARLY NEXT
WEEK AS AN UPPER LEVEL RIDGE MOVES EAST ACROSS THE WESTERN UNITED
STATES. DOWNSLOPE FLOW WILL BE DEVELOPING IN WESTERN KANSAS AND SOME
COOLER AIR WILL BE RECIRCULATING AROUND THE SURFACE HIGHS IN CENTRAL
KANSAS. THIS WILL RESULT IN A GRADIENT OF TEMPERATURES ACROSS
SOUTHWEST KANSAS THROUGH MID WEEK. AT THIS TIME BASED ON THE
925-850MB WARMING TREND SUGGESTED BY THE GFS AND ECMWF EARLY NEXT
WEEK THE HIGHS REBOUNDING BACK INTO THE 60S BY TUESDAY STILL LOOKS
REASONABLE ACROSS FAR WESTERN KANSAS. A FEW LOWER 70S ARE NOT OUT OF
THE QUESTION IN FAR SOUTHWEST KANSAS BY WEDNESDAY. FURTHER EAST AM A
LITTLE CONCERNED ABOUT HOW QUICKLY THE TEMPERATURES WILL REBOUND
ACROSS SOUTH CENTRAL AND NORTH CENTRAL KANSAS. AT THIS TIME HAVE
DECIDED TO STAY CLOSE TO THE CREXTENDFCST_INIT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 606 AM CDT THU MAR 14 2013
THE NAM AND HRRR WERE IN DECENT AGREEMENT IN MOVING A SURFACE
BOUNDARY ACROSS WESTERN KANSAS EARLY THIS MORNING. AS THIS
BOUNDARY PASSES A NORTHWEST WIND WILL DEVELOP. NORTHWEST WINDS AT
AROUND 10KTS WILL THEN BECOME LIGHT AND VARIABLE BY 00Z FRIDAY.
BASED ON BUFR SOUNDINGS VFR CONDITIONS ARE EXPECTED TO CONTINUE
FOR THE NEXT 24 HOURS.
&&
.FIRE WEATHER...
ISSUED AT 320 AM CDT THU MAR 14 2013
ON FRIDAY THE AFTERNOON RELATIVE HUMIDITIES WILL FALL BACK INTO THE
10 TO 15 PERCENT RANGE ACROSS POTIONS OF WESTERN KANSAS. SUSTAINED
WIND SPEEDS FRIDAY AFTERNOON HOWEVER ARE EXPECTED TO AVERAGE BETWEEN
10 TO 15 MPH. ALTHOUGH CRITICAL FIRE WEATHER CONDITIONS ARE NOT
EXPECTED...GIVEN THE LOW RELATIVE HUMIDITIES FRIDAY AFTERNOON THIS
WILL RESULT IN ELEVATED FIRE WEATHER CONCERNS ALONG AND WEST OF
HIGHWAY 83.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 74 41 82 43 / 0 0 0 0
GCK 74 40 82 42 / 0 0 0 0
EHA 74 40 83 43 / 0 0 0 0
LBL 76 40 83 43 / 0 0 0 0
HYS 70 41 80 40 / 0 0 0 0
P28 74 42 83 45 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HOVORKA_42
LONG TERM...BURGERT
AVIATION...BURGERT
FIRE WEATHER...BURGERT
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
355 PM EDT THU MAR 14 2013
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN AMPLIFIED UPPER LEVEL
PATTERN ACROSS THE CONUS. NORTHERN STREAM FLOW FORMS A LARGE
LONGWAVE RIDGE ACROSS THE INTER-MOUNTAIN WEST BEFORE CARVING A
LONGWAVE TROUGH DOWNSTREAM OVER THE EASTERN HALF OF THE NATION. THE
FLORIDA PENINSULA RESIDES AT THE BASE OF THIS DEEP TROUGH EMBEDDED
WITHIN A DEEP LAYER NW FLOW PATTERN. 12Z KTBW SOUNDING PROFILE SHOWS
A DRY COLUMN THROUGH A DEEP LAYER ABOVE OUR HEADS WITH A PW VALUE OF
ONLY AROUND 0.20". PROFILE BECOMES MORE MOIST ABOVE 25-30KFT AND HAS
ALLOWED FOR A FEW PASSING PATCHES OF CIRRUS TODAY...ACROSS THE
SOUTHERN HALF OF THE AREA. OTHER THAN SOME PASSING CIRRUS...THE
ABUNDANT SUNSHINE AND COOL TEMPERATURES FOR MID MARCH CONTINUE FOR
THE REMAINDER OF THE AFTERNOON.
AT THE SURFACE...A LARGE RIDGE OF HIGH PRESSURE IS EXPANDING ALONG
THE NORTHERN GULF COAST AND WILL SLOWLY APPROACH AND SETTLE OVER-TOP
THE PENINSULA LATER TONIGHT AND FRIDAY.
&&
.SHORT TERM (TONIGHT THROUGH SATURDAY NIGHT)...
TONIGHT...WEAKENING GRADIENT AND LOSS OF DIURNAL MIXING SHOULD
SETTLE WINDS DOWN AND EVENTUALLY ALLOW SOME PLACES TO DECOUPLE LATE
ACROSS THE INTERIOR NATURE COAST...AND POSSIBLY FOR MORE SHELTERED
LOCATIONS DOWN TOWARD HIGHLANDS/DE SOTO/HARDEE COUNTIES. WHILE
EVERYWHERE WILL BE CHILLY FOR MID MARCH TONIGHT (WIDESPREAD UPPER
30S - MID 40S)...THOSE AREAS THAT DO DECOUPLE WILL HAVE THE BEST
CHANCE AT REACHING THE LOWER/MIDDLE 30S WITH SOME PATCHY FROST
TOWARD DAWN. THE MOST FAVORABLE CONDITIONS OF LIGHT WINDS...DRY
CONDITIONS...AND SMALL DEWPOINT DEPRESSIONS APPEAR TO ALIGN ACROSS
THE NATURE COAST...MAINLY TO THE NORTH OF I-4...AND A FROST ADVISORY
HAS BEEN ISSUED FOR THESE AREAS. AT THIS POINT...WIDESPREAD FROST IS
NOT ANTICIPATED...HOWEVER WITH THE GROWING SEASON UNDERWAY...EVEN
PATCHY FROST WILL CAUSE PROBLEMS FOR YOUNG AND SENSITIVE PLANTS.
FRIDAY/FRIDAY NIGHT...
AFTER THE CHILLY EARLY MORNING...FRIDAY IS LOOKING TO BE A BEAUTIFUL
DAY AS HIGH PRESSURE SETTLES ON TOP OF THE REGION. FORECAST WILL
SHOW PLENTY OF SUNSHINE...LIGHT WINDS...AND TEMPERATURES INTO THE
LOWER 70S NORTH AND MIDDLE 70S SOUTH. AN LIGHT ONSHORE WIND
COMPONENT LATE IN THE DAY ALONG THE NATURE COAST MAY HELP COOL TEMPS
BACK DOWN INTO THE 60S FOR THE SECOND HALF OF THE AFTERNOON. WITH
THE SURFACE HIGH NEARBY AND A DRY COLUMN...TEMPERATURES WILL ONCE
AGAIN BECOME QUITE CHILLY FRIDAY NIGHT. AT THIS TIME IT APPEARS THAT
FRIDAY NIGHT WILL BE AT LEAST SEVERAL DEGREES WARMER THAN
TONIGHT...AND SO NOT EXPECTING A FROST THREAT FOR EVEN THE COLDEST
LOCATIONS. HOWEVER...TEMPERATURES WILL NEED TO BE MONITORED CLOSELY
IN CASE ANY COOLER TRENDS DEVELOP.
SATURDAY/SATURDAY NIGHT...
THE WARMING TREND CONTINUES INTO THE WEEKEND. SURFACE HIGH PRESSURE
WILL REMAIN OVER THE PENINSULA UNDERNEATH A ZONAL MID/UPPER LEVEL
FLOW PATTERN. AFTER A COOL START TO THE DAY...TEMPERATURES WILL
QUICKLY WARM UNDER ABUNDANT SUNSHINE TO NEAR NORMAL OR EVEN SLIGHTLY
ABOVE NORMAL VALUES. CURRENT FORECAST WILL SHOW UPPER 70S TO NEAR 80
NORTH AND LOWER 80S SOUTH AWAY FROM THE IMMEDIATE COAST. AT THE
BEACHES...THE LIGHT GRADIENT AND STRONG TERRESTRIAL HEATING SHOULD
FORCE AT LEAST A FEEBLE SEA-BREEZE CIRCULATION TO HOLD TEMPS DOWN
SEVERAL DEGREES OFF THE COOLER SHELF WATERS. SATURDAY NIGHT SEES
TEMPS DIP INTO THE MIDDLE 40S FOR THE COOLEST SPOTS WITH UPPER 40S
TO LOWER 50S MORE COMMON.
&&
.LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)...
ZONAL FLOW ACROSS THE CONUS WILL PERSIST THROUGH THE EXTENDED PERIOD
WITH A STRONG U/L DISTURBANCE MOVING FROM THE PACIFIC NORTHWEST
SATURDAY NIGHT...ACROSS THE UPPER MISSISSIPPI VALLEY MONDAY...THEN
DIGGING THROUGH THE OHIO RIVER VALLEY AND NEW ENGLAND ON TUESDAY.
U/L DYNAMICS WILL REMAIN WELL NORTH OF OUR FORECAST AREA...HOWEVER
THE DIGGING TROUGH OVER THE EASTERN HALF OF THE U.S. ON TUESDAY WILL
PUSH A COLD FRONT SOUTH ACROSS WEST CENTRAL AND SOUTHWEST FLORIDA
TUESDAY AND TUESDAY NIGHT WITH A SLIGHT CHANCE OF A LIGHT SHOWER.
SURFACE HIGH PRESSURE WILL BUILD OVER THE FORECAST AREA BEHIND THE
FRONT ON WEDNESDAY WITH SLIGHTLY COOLER DRIER AIR ADVECTING OVER THE
REGION.
&&
.AVIATION...
VFR CONDITIONS WITH SOME HIGH CIRRUS. GUSTY NORTHERLY WINDS BACK TO
NW AND DIMINISH LATE AFTERNOON.
&&
.MARINE...
EXERCISE CAUTION WINDS AND SEAS WILL CONTINUES THROUGH THIS EVENING
FOR WATERS SOUTH OF TARPON SPRINGS...EXCLUDING TAMPA BAY. A
WEAKENING GRADIENT AS HIGH PRESSURE SETTLES OVER THE EASTERN GULF
WILL DROP WINDS AND SEAS BELOW HEADLINE CRITERIA BY LATE
TONIGHT...AND THROUGH AT LEAST THE FIRST HALF OF THE UPCOMING
WEEKEND.
&&
.FIRE WEATHER...
A VERY DRY AIR MASS WILL REMAIN IN PLACE THROUGH SATURDAY. AN
EXTENDED PERIOD OF CRITICALLY LOW RELATIVE HUMIDITY WILL ONCE AGAIN
COMBINE WITH ERC VALUES OF 37 OR HIGHER ACROSS
PINELLAS...POLK...SARASOTA...AND LEE COUNTIES TO RESULT IN RED FLAG
CONDITIONS FROM MIDDAY FRIDAY THROUGH EARLY FRIDAY EVENING. LONG
DURATIONS OF CRITICALLY LOW RELATIVE HUMIDITY ARE EXPECTED ACROSS
THE REMAINING COUNTIES WITHIN THE FORECAST AREA AS WELL...HOWEVER
FORECAST ERC VALUES ARE CURRENTLY BELOW 37...PREVENTING RED FLAG
CONDITIONS FROM BEING MET.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 44 70 51 76 / 0 0 0 0
FMY 44 76 52 80 / 0 0 0 0
GIF 40 74 47 79 / 0 0 0 0
SRQ 44 70 48 75 / 0 0 0 0
BKV 33 72 38 79 / 0 0 0 0
SPG 52 70 56 76 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR CHARLOTTE-
LEE-PINELLAS-POLK-SARASOTA.
RED FLAG WARNING FROM NOON TO 8 PM EDT FRIDAY FOR LEE-
PINELLAS-POLK-SARASOTA.
FROST ADVISORY FROM 4 AM TO 9 AM EDT FRIDAY FOR CITRUS-
HERNANDO-LEVY-PASCO-SUMTER.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...OGLESBY
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1021 AM MDT THU MAR 14 2013
.UPDATE...
ISSUED AT 1012 AM MDT THU MAR 14 2013
RAISED TEMPERATURES SEVERAL DEGREES THIS AFTERNOON BASED ON 12Z
RAOBS...LATEST NUMERICAL GUIDANCE...AND THE FACT THAT MANY
OBSERVATIONS ARE RUNNING ABOUT 10 DEGREES WARMER THAN YESTERDAY AT
THIS TIME.
&&
.SHORT TERM...(TODAY AND THURSDAY)
ISSUED AT 308 AM MDT THU MAR 14 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOWS LARGE SCALE TROUGH IN
PLACE ACROSS NEW ENGLAND AND A RIDGE CENTERED ACROSS THE SOUTHWEST
US. BETWEEN THESE FEATURES NW FLOW EXTENDS ACROSS THE NORTHERN AND
CENTRAL PLAINS. EMBEDDED WITHIN THE MEAN FLOW SEVERAL WEAK SHORTWAVE
TROUGHS ARE PRODUCING HIGH CLOUDS WHICH ARE QUICKLY STREAMING FROM
THE NW TO SE ACROSS THE CWA. SOUNDS ARE VERY DRY SO DESPITE PRESENCE
OF ELEVATED FORCING WE SHOULD CONTINUE TO SEE DRY CONDITIONS.
H5 RIDGE IN OVER THE SOUTHWEST US IS PROGGED TO FLATTED WITH NW FLOW
TRANSITIONING TO WESTERLY FLOW BY FRIDAY. BL FLOW WILL CONTINUE TO
BE WESTERLY/DOWNSLOPE TODAY WITH DRY/WARM AIRMASS EXPECTED TODAY AND
FRIDAY. H85 TEMPS ARE ADVERTISED TO BE 2-3C WARMER THAN WED AND ON
FRI ALMOST 5-10C WARMER. ACCOUNTING FOR SIMILAR BIAS WE COULD SEE
TEMPS IN THE LOW TO MID 70S FOR MOST LOCATIONS TODAY AND 80F OR
WARMER ON FRI. THE COMBINATION OF WARM TEMPS/VERY DRY
CONDITIONS...COMBINED WITH INCREASING WINDS FRI AFTERNOON COULD LEAD
TO DEVELOPMENT OF CRITICAL FIRE CONDITIONS. RIGHT NOW CALCULATED RH
VALUES RANGE FROM NEAR 10 PERCENT IN OUR SOUTHWEST TO AROUND 15
PERCENT IN THE NORTH. WITH UNIDIRECTIONAL WESTERLY FLOW AND
STRENGTHENING SURFACE TROUGH WE SHOULD SEE AT LEAST BREEZY
CONDITIONS DEVELOP FRI AFTERNOON THOUGH LOCATION/MAGNITUDE OF
STRONGEST GUSTS IS STILL IN QUESTION. LOWEST RH VALUES AND WINDS IN
HE 20-25MPH RANGE MAY NOT OVERLAP BUT IT COULD BE CLOSE. WILL NOT
ISSUE ANY FIRE WEATHER HIGHLIGHTS DURING THIS FORECAST CYCLE AND WILL
ALLOW SUBSEQUENT SHIFTS TO FINE TUNE.
A BACKDOOR COLD FRONT WILL DROP SOUTH OVER THE CWA BY SATURDAY. WEAK
ENERGY WITHIN MEAN W/NW FLOW AHEAD OF THIS FRONT AND ELEVATED
INSTABILITY COULD SUPPORT SHOWER DEVELOPMENT LATE FRIDAY NIGHT WITH
INCREASING COVERAGE WITH FROPA SAT AND APPROACHING SHORTWAVE TROUGH
OVER THE PAC NW SAT NIGHT. MOISTURE PROFILES REMAIN DRY BELOW 600MB
THROUGH SAT AND REALLY DO NO BEGIN TO COMPLETELY MOISTEN UNTIL
SATURDAY AFTERNOON/EVENING. MOISTURE ADVECTION IS ALSO FAIRLY
UNIMPRESSIVE AHEAD OF THIS FRONT WITH BETTER MOISTURE RETURN
GENERALLY IN THE SOUTH. I DECIDED AGAINST INCREASING POPS SAT/SAT
NIGHT BEYOND CHANCE CATEGORY AND LEANED TOWARDS THE LOWER END OF
GUIDANCE ON QPF WITH PRECIP THAT OCCURS EXPECTED TO BE ON LIGHTER
SIDE. WITH MOST GUIDANCE ON THE WARMER SIDE RAIN SHOWERS WILL
LIKELY BE FAVORED WITH ONLY A BRIEF RAIN/SNOW MIX POSSIBLE LATE
SAT NIGHT ASSUMING WE SEE EVAPORATIVE COOLING PROCESSES. I DOUBT
WE WOULD SEE MUCH SNOW ACCUMULATION SAT NIGHT IF WE DID
TRANSITION OVER WITH LIGHT PRECIP RATES AND WARM GROUND TEMPS
EXPECTED.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 308 AM MDT THU MAR 14 2013
MODELS HAVE COME INTO SOMEWHAT BETTER AGREEMENT WITH THE WEATHER
SYSTEM EXPECTED TO SWING ACROSS THE PLAINS SUNDAY EVENING INTO
MONDAY MORNING...HOWEVER QUESTIONS STILL LINGER WITH RESPECT TO
TEMPERATURES AND THUS WEATHER TYPES.
THE GFS...CANADIAN AND EUROPEAN MODELS ARE IN FAIRLY GOOD AGREEMENT
WITH RESPECT TO THE TIMING OF STRONG UPPER LEVEL SHORTWAVE AND
DEVELOPMENT OF A SURFACE LOW AS THE SHORTWAVE MOVES ACROSS THE
PLAINS. THE GFS MODEL STANDS OUT FROM THE CANADIAN AND EUROPEAN
MODELS IN THAT IT IS STILL FORECASTING MUCH WARMER TEMPERATURES
DURING THE AFTERNOON ON SUNDAY. THE EUROPEAN AND CANADIAN ARE
SUGGESTING A COOLER...MORE STABLE ATMOSPHERE WHICH WOULD LIMIT
INSTABILITY AND WOULD GIVE A BETTER CHANCE AT SOME WINTRY
PRECIPITATION EARLY ON SUNDAY MORNING. THEREFORE...FOR THE TIME
BEING A RAIN SNOW MIX HAS BEEN MENTIONED FOR ROUGHLY THE NORTHERN
HALF OF THE FORECAST AREA SUNDAY MORNING DUE TO TEMPERATURE
UNCERTAINTY. IF THE GFS PANS OUT...THERE WOULD BE A BETTER CHANCE OF
SOME THUNDERSTORMS ALONG AND AHEAD OF THE COLD FRONT THAT WILL MOVE
THROUGH SUNDAY EVENING. EITHER WAY...ALL THREE MODELS ARE
FORECASTING PRECIPITATION ALONG AND AHEAD OF THE COLD FRONT. THE
QUESTION THAT REMAINS IS WILL THERE BE THUNDERSTORMS AND THUS
HEAVIER PRECIPITATION AMOUNTS POSSIBLE. ANOTHER CAUSE FOR CONCERN IS
THAT THE CANADIAN AND EUROPEAN MODELS ARE SUGGESTING A WARM FRONT
WILL REMAIN OVER THE AREA THROUGHOUT THE DAY ON SUNDAY WITH
PRECIPITATION DEVELOPING ALONG THE FRONT. IF THIS WERE TO
OCCUR...THE POPS ARE UNDERDONE DURING THE DAY ON SUNDAY AND WOULD
NEED TO BE INCREASED IN LATER FORECAST CYCLES. ALL PRECIP DURING THE
DAYLIGHT HOURS ON SUNDAY SHOULD NOT BE FROZEN IN NATURE.
ONCE THE COLD FRONT PUSHES THROUGH SUNDAY NIGHT...PRECIPITATION
CHANCES WILL DECREASE. A BRIEF CHANGE TO SNOW IS FORECAST BEHIND THE
FRONT AS TEMPERATURES ALOFT COOL ENOUGH TO ALLOW SNOW TO REACH THE
GROUND WITHOUT MELTING. THE EUROPEAN MODEL IS ABOUT 6 HOURS SLOWER
THAN THE OTHER TWO MODELS. THIS WOULD MEAN A BETTER CHANCE FOR SNOW
BEHIND THE FRONT ACROSS MAINLY NORTHEAST PORTIONS OF THE FORECAST
AREA. TRIED TO REFLECT CHANCES OF PRECIPITATION DECREASING BEHIND
THE FRONT AFTER MIDNIGHT BASED ON MODEL GUIDANCE.
FOLLOWING THIS WEATHER SYSTEM...A RIDGE OF HIGH PRESSURE WILL BUILD
IN ACROSS THE ROCKIES...LEADING TO DRY WEATHER ACROSS THE HIGH
PLAINS SINCE ANY DISTURBANCES WILL STAY WELL TO THE NORTH. MODELS
ARE BEGINNING TO SUGGEST A LARGE LONGWAVE TROUGH DEVELOPING OVER THE
WESTERN UNITED STATES AND MOVING ACROSS THE CENTRAL PLAINS BY THE
MIDDLE TO END OF NEXT WEEK. UNFORTUNATELY THE GFS AND EUROPEAN
MODELS HAVE LARGE DIFFERENCES BETWEEN THEIR SOLUTIONS WITH THE GFS
ABOUT A DAY FASTER THAN THE EUROPEAN. THE CR INIT PROCEDURE
SUGGESTED LIKELY POPS BEGINNING THURSDAY NIGHT BUT HAVE CUT THOSE IN
HALF TO START DUE TO THE LARGE DIFFERENCES IN MODEL SOLUTIONS.
AS THE RIDGE BUILDS IN...WARMER WEATHER WILL AGAIN RETURN. HAVE
INCREASED TEMPERATURES SLIGHTLY AS THE PATTERN WILL BE FAVORABLE FOR
A WARMING TREND. TEMPERATURES SHOULD BE ABOVE NORMAL FROM THIS
TUESDAY ONWARD WITH NEAR NORMAL TEMPERATURES BEHIND THE COLD
FRONT THIS MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1012 AM MDT THU MAR 14 2013
VFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK THROUGH THE FORECAST
PERIOD...ONLY PERIODS OF CIRRUS CLOUDS WILL MOVE OVER THE SITES.
BY 18Z FRIDAY...SURFACE WINDS WILL NORTHWEST AROUND 15 KTS WITH
GUSTS TO 25 KNOTS.
&&
.FIRE WEATHER...
ISSUED AT 1012 AM MDT THU MAR 14 2013
RELATIVE HUMIDITIES WILL RANGE FROM 10 TO 15 PERCENT SOUTH OF
INTERSTATE 70 FRIDAY AFTERNOON. HOWEVER...SURFACE WINDS WILL ONLY
BE AROUND 15 KNOTS. THEREFORE...WILL NOT HOIST ANY FIRE WEATHER
HIGHLIGHTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...DR
LONG TERM...RRH
AVIATION...MENTZER
FIRE WEATHER...MENTZER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
400 PM EDT THU MAR 14 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 357 PM EDT THU MAR 14 2013
WATER VAPOR LOOP AND RUC ANALYSIS SHOWS A NW ALOFT OVER THE UPPER
GREAT LAKES BETWEEN THE WRN CONUS RDG AND TROF OVER THE EAST COAST.
ONE SHORTWAVE MOVING INTO NW ONTARIO WAS BRINGING AN INCREASE IN
CLOUD COVER THERE SOUTHWARD INTO THE ARROWHEAD OF MN AND NW WI. HIGH
PRESSURE OVER MUCH OF THE WRN GREAT LAKES HAS SUPPORTED MOSTLY SUNNY
SKIES INTO THE AFTERNOON HOURS ACROSS MUCH OF THE CWA. AS A RESULT
OF THE SUNNY SKIES...TEMPERATURES THUS FAR HAVE RISEN INTO THE MID
30S ACROSS MUCH OF THE INTERIOR WEST THIS AFTERNOON.
THE ONTARIO SHORTWAVE IS EXPECTED TO REMAIN WELL NORTH OF LAKE
SUPERIOR AS IT CONTINUES TO TRACK ESE ACROSS THE PROVINCE TONIGHT.
MUCH OF THE MOISTURE/FORCING AND THUS SNOW SHOULD STAY OVER THE
NORTHEAST HALF OF LAKE SUPERIOR...BUT THE ASSOCIATED SURFACE TROUGH
AND LOW LEVEL MOISTURE ON THE BACK SIDE SHOULD BE ENOUGH TO PRODUCE
A SOME SNOW SHOWERS ACROSS UPPER MICHIGAN TONIGHT. WILL CONTINUE
MENTION OF HIGHER CHC TO LIKELY POPS ACROSS THE NRN TIER WITH THE
PASSAGE OF THE FRONT. AS WINDS SHIFT TO THE WEST AND THEN
NORTHERLY...EXPECT A TRANSITION TO LAKE ENHANCED/LAKE EFFECT SNOW
AND WILL CONTINUE HIGHER POPS FOR NORTH FACING HIGHER TERRAIN WHERE
UPSLOPE WILL AID PRECIPITATION. SNOWFALL AMOUNTS WILL LIKELY BE
LIMITED AS TEMPS AT TOP OF MIXED LAYER (BTWN 900-875 MB) ONLY LOWER
TO ONLY AROUND -11C. OVER MOST OF THE NORTHERN AREAS...THE
PRECIPITATION WILL LIKELY BE SNOW. BUT FCST SNDGS SUGGEST DRYING
ALOFT BEHIND THE FRONT LATE TONIGHT...ESPECIALLY TOWARDS THE
IRONWOOD AREA...WHERE CLOUD LAYER IS IN THE MARGINAL AREA FOR ICE
CRYSTALS. WILL MENTION SLIGHT CHC FOR -FZDZ ALONG WITH SNOW LATE
TONIGHT. GIVEN MARGINALLY COLD TEMPS...EXPECT TOTAL SNOW
ACCUMULATION TO BE INCH OR LESS ACROSS THE NRN TIER COUNTIES.
MODELS CONTINUE TO TREND WEAKER AND FARTHER SOUTH WITH NEXT
SHORTWAVE MOVING IN OFF THE PAC NW FOR FRI AFTERNOON WITH MAJORITY
OF MODELS KEEPING RESULTING PCPN TO THE SOUTH...MAINLY OVER CENTRAL
AND SRN WI. DUE TO THESE TRENDS HAVE DECIDED TO CUT BACK POPS EVEN
MORE DRAMATICALLY OVER THE CWA ON FRIDAY. JUST HAVE SLIGHT CHC POPS
IN OVER THE NRN COUNTIES FOR LINGERING LIGHT LES...MAINLY IN THE
MORNING. HAVE TRIMMED BACK POPS FOR SYSTEM SNOW TO SLIGHT CHC ALONG
THE WI BDR FRIDAY MORNING...ONLY RAISING TO 30 PCT POPS IN THE
AFTERNOON AS SYSTEM SLIDES JUST TO THE SOUTH.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 357 PM EDT THU MAR 14 2013
FRI NGT...MODELS HAVE CONTINUED TREND TOWARD A FARTHER S TRACK FOR
CLIPPER LO THRU THE OH RIVER VALLEY...ALLOWING DRY AIR ASSOCIATED
WITH HI PRES OVER ONTARIO TO HAVE A MORE SGNFT INFLUENCE ON UPR MI
WX. ALTHOUGH SOME DPVA/H85-5 QVECTOR CNVGC ASSOCIATED WITH A
TRAILING SHRTWV IS FCST TO MOVE OVER UPR MI AND H85 TEMPS FCST AS LO
AS -18C WOULD BE SUFFICIENT FOR LES...THE ACYC NATURE OF THE FCST
H925-85 FLOW...INVRN BASE NOT FAR FM 3K FT AGL...AND H85 DEWPTS FCST
AS LO AS -20C TO -40C WL NEGATIVELY IMPACT THIS POTENTIAL. GIVEN
THESE NEGATIVES AND THE OVERALL TREND TOWARD A FARTHER S TRACK FOR
THE CLIPPER...CUT PREVIOUS FCST POPS A BIT...WITH THE SOMEWHAT HIER
CHC POPS ALONG THE WI BORDER CLOSER TO THE LO TRACK AND IN THE
UPSLOPE AREAS OF THE NCNTRL IN LLVL NNE FLOW.
SAT...ANY LINGERING PCPN FM FRI NGT SHOULD DIMINISH EARLY AS THE
LLVL FLOW SHIFTS TO THE WSW IN ADVANCE OF APRCHG COLD FNT ASSOCIATED
WITH NEXT ARCTIC BRANCH SHRTWV DIGGING SEWD THRU ONTARIO. THIS FNT
IS FCST TO PUSH THRU THE NW ZNS LATE IN THE DAY. SINCE THE MOST
IMPRESSIVE ASSOCIATED DPVA AND LARGER SCALE FORCING ARE FCST TO PASS
TO THE N ON THE CYC SIDE OF UPR JET AXIS ACRS LK SUP AND MSTR RETURN
AHEAD OF THE COLD FROPA WL BE QUITE LIMITED WITH FCST PWAT UNDER
0.20 INCH...SUSPECT ACCOMPANYING PCPN WL BE LIMITED TO THE W HALF
WITH ONLY LO CHC POPS APPROPRIATE. THE ONE EXCEPTION MIGHT BE THE
AREA FM ONTONAGON COUNTY THRU THE KEWEENAW...WHICH WL BE CLOSER TO
THE SHARPER DPVA...WHERE UPSLOPE W FLOW ACCOMPANYING THE FROPA MIGHT
RESULT IN SOME ENHANCEMENT...AND WHERE FCST SDNGS SHOW FAIRLY DEEP
UNSTABLE LYR AS WELL AS SOME SHARP UVV WITHIN A DGZ SEVERAL THOUSAND
FEET DEEP. AT LEAST A BRIEF PERIOD OF HEAVIER... MORE NMRS SHSN
APPEAR PSBL IN THIS AREA IN THE AFTN.
SAT NGT...AS COLD FNT SWINGS THRU THE UPR LKS IN THE EVNG...EXPECT
THE SAME ADVANTAGES THAT WOULD BRING HIER POPS TO THE KEWEENAW TO
CAUSE MORE NMRS SHSN OVER AREAS NEAR LK SUP E OF MQT. BUT QUICK
ARRIVAL OF LARGER SCALE SUBSIDENCE IN THE DNVA/CAD BEHIND THE
SHRTWV...FCST STEADY TRANSITION TO MORE ACYC FLOW...AND EXPECTED
DRYNESS OF INCOMING AIRMASS WL TEND TO LIMIT THE LES IN THE WAKE OF
THE FROPA DESPITE ARRIVAL OF H85 THERMAL TROF/TEMPS ARND -20C. BEST
CHC FOR MORE PERSISTENT SHSN WL BE IN THE NW WIND SN BELTS E OF
MQT...WHERE LONGER FETCH/MOISTENING ACRS THE LK IN LLVL NW FLOW WL
MITIGATE THE LARGER SCALE DRYING. THE FROPA SHOULD BE DRY OVER THE
SCENTRAL GIVEN TRACK OF DYNAMIC SUPPORT/LACK OF MOISTENING.
SUN...EXPECT SFC HI PRES TO BLD OVER THE CWA IN ADVANCE OF APRCHG H5
SHRTWV RDG AND UNDER CONFLUENT WNW FLOW ALF. LINGERING SHSN NEAR LK
SUP SHOULD END BY AFTN WITH A COMBINATION OF NEGATIVE DYNAMICS/
INCRSG ACYC FLOW/DRYING/DAYTIME HEATING WITH INCRSG MARCH INSOLATION
DISRUPTING THE LES PROCESS. IN FACT...THE DAY IS LIKELY TO TURN
MOSUNNY IN THE AFTN W-E WITH WSHFT TO THE S FOLLOWING PASSAGE OF HI
PRES RDG AXIS. DESPITE THE RETURN OF MORE SUNSHINE...THE DAY WL
FEATURE BLO NORMAL MAX TEMPS MAINLY IN THE 20S WITH H85 TEMPS
RECOVERING TO -12C TO -14C IN THE AFTN.
SUN NGT THRU TUE...ALTHOUGH THERE IS INCRSG CONSENSUS A SGNFT LO
PRES WL DVLP SOMEWHERE NEAR THE GRT LKS EARLY NEXT WEEK...THE EXACT
DETAILS ON TIMING AND LOCATION/IMPACT ON UPR MI WL DEPEND ON THE
PHASING OF SHRTWVS EMBEDDED IN THE ARCTIC AND POLAR BRANCHES. SOME
FCSTS SUCH AS THE 00Z CNDN MODEL SHOW THE SHRTWVS REMAINING OUT OF
PHASE FOR A LONGER TIME WITH SFC LO INTENSIFICATION TOO FAR TO THE E
TO HAVE A REAL BIG IMPACT ON UPR MI. THE 00Z ECWMF ON THE OTHER HAND
INDICATED A QUICKER PHASING WITH A DEEP SFC LO OVER LOWER MI MON NGT
HAVING A SGNFT IMPACT ON THE CWA. ALTHOUGH THE NUMERICAL MODELS
OFTEN HAVE A DIFFICULT TIME WITH THE DETAILS OF THESE
INTERACTIONS...THE 12Z RUNS HAVE TRENDED TOWARD THE FASTER PHASING/
DEEPER LO CLOSER TO UPR MI. SO BUMPED POPS UP A BIT TO LIKELY OVER
THE CONSENSUS CHC POPS FCST.
EXTENDED...AS HAS BEEN COMMON RECENTLY...THE UPR FLOW DURING THE
EXTENDED WL FEATURE A BLOCKING PATTERN WITH AN UPR RDG OVER NE
CANADA HOLDING IN PLACE A CUTOFF LO OVER THE NE CONUS/FAR SE CANADA.
THIS NEGATIVE NAO PATTERN COMMONLY RESULTS IN BLO NORMAL TEMPS OVER
THE GREAT LKS AS COLD AIR IS LOCKED IN PLACE WITH N-NE FLOW BTWN
HUDSON BAY HI PRES AND THE CLOSED LO TO THE E. COMBINATION OF TREND
TOWARD DRIER...MORE ACYC FLOW WITH HUDSON BAY HI PRES RDG
DOMINATING/SUBSIDENCE WARMING OF H85 TEMPS/STRENGTHENING MAR SUN WL
TEND TO DISSIPATE LES THAT WL STILL BE ONGOING ON TUE NGT INTO WED
IN LLVL CYC NW FLOW LEFT IN THE WAKE OF SLOWLY DEPARTING SFC LO PRES
TOWARD THE CNDN MARITIMES/CUTOFF LO IN PLACE THERE. CONSIDERING THE
STRENGTH OF THE HUDSON BAY HI PRES/NEGATIVE NAO...THE 12Z GFS SEEMS
TOO AGGRESSIVE AT LIFTING A LO PRES NE TOWARD THE UPR LKS NEXT
WED/THU. EXCEPT FOR LINGERING LES ON WED...WENT DRY FOR THESE DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 142 PM EDT THU MAR 14 2013
HIGH PRESSURE OVER THE UPPER GREAT LAKES REGION WILL GET PUSHED
SLOWLY EASTWARD AS A COLD FRONT APPROACHES FROM NORTHWEST MINNESOTA
THIS LATE THIS AFTERNOON AND EVENING. EXPECT CONDITIONS TO LOWER TO
MVFR AT BOTH KIWD AND KCMX LATE THIS AFTERNOON/TOWARD EVENING WITH
SOME SCT SNOW SHOWERS EXPECTED AS WINDS TURN NORTH-NORTHWESTERLY
BEHIND THE FRONT LEADING TO LIGHT UPSLOPE CONDITIONS AND SOME LAKE
EFFECT SNOW. AT KSAW...EXPECT CONDITIONS TO LOWER TO MVFR BY LATE
EVENING WITH THE ARRIVAL OF THE COLD FRONT AS WINDS VEER INITIALLY
WESTERLY AND THEN NORTHERLY AFTER MIDNIGHT. DRIER AIR WILL ARRIVE AT
MID-LEVELS LATE TONIGHT AND COULD BRING THE POTENTIAL FOR FREEZING
DRIZZLE...ESPECIALLY AT KIWD...AS THE CLOUD LAYER STRUGGLES TO REACH
THE FAVORABLE ICE CRYSTAL ZONE. UPSLOPE NORTHERLY WINDS WILL LIKELY
MAINTAIN MVFR CONDITIONS THROUGH FRIDAY MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT THU MAR 14 2013
HIGH PRESSURE CURRENTLY OVER THE UPPER GREAT LAKES REGION WILL SLIDE
EAST TODAY AND LEAD TO INCREASING SOUTHERLY FLOW AHEAD OF AN
APPROACHING COLD FRONT. THIS FRONT WILL MOVE ACROSS LAKE SUPERIOR
TONIGHT AND SHIFT WINDS TO THE NORTH AT 20-30KTS. A HIGH PRESSURE
RIDGE WILL THEN NOSE OVER LAKE SUPERIOR ON FRIDAY FROM A PARENT HIGH
OVER NORTHERN ALBERTA AS NORTH WINDS GRADUALLY DIMINISH TO 15-25
KTS.
STEADY NE WINDS UP TO 25 KTS WILL DIMINISH FRI NIGHT AS HI PRES
RIDGE AXIS BUILDS OVER THE UPPER GREAT LAKES. A SHARP COLD FRONT
WILL SWING ACROSS THE AREA LATE SAT...WITH NW WINDS IN ITS WAKE
CLIMBING UP TO 30 KTS AND FREEZING SPRAY DEVELOPING. EXPECT THESE
WINDS TO DIMINISH QUICKLY SUN AS ANOTHER AREA OF HI PRES BUILDS INTO
THE UPPER LAKES. ANOTHER PERIOD OF STRONG N-NW WINDS ARE LIKELY ON
MON INTO TUE AS A LO PRES DEEPENS NEAR LOWER MI AND SHIFTS SLOWLY
INTO SE ONTARIO. DEPENDING ON HOW QUICKLY THIS LO DEVELOPS...NW
GALES/HEAVY FREEZING SPRAY WILL BE POSSIBLE...ESPECIALLY MON NIGHT
AND TUE. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KC
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT THU MAR 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL HOLD OVER THE GULF COAST AND SOUTHEAST STATES
THROUGH EARLY FRIDAY. A WARM FRONT WILL MOVE NORTHEASTWARD THROUGH
THE CAROLINAS ON FRIDAY... THEN A BACKDOOR COLD FRONT WILL DROP INTO
THE AREA FROM THE NORTH BY LATE SATURDAY... AND REMAIN ACROSS NORTH
CAROLINA THROUGH SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 305 PM THURSDAY...
THROUGH TONIGHT: WE`RE ALREADY SEEING SOME OROGRAPHIC CIRRUS OVER
THE FAR WRN CWA... AND THE MID/HIGH CLOUDS ASSOCIATED WITH THE MID
LEVEL SHORTWAVE DIVING QUICKLY TO THE SOUTHEAST TOWARD GA/SC IS ON
TRACK TO OVERSPREAD THE CAROLINAS WITHIN THE NEXT HOUR OR TWO.
EXPECT SKIES TO BECOME PARTLY TO MOSTLY CLOUDY... WITH THE THICKEST
CLOUDS IN THE SOUTHWEST CWA. CLOUD COVER IS EXPECTED TO DECREASE
TOWARD MORNING AS THE WAVE PUSHES OFF THE GA/SC COAST. WITH THE
CLOUDS EXPECTED TO PROVIDE ENOUGH DOWNWARD IR TO TEMPER NIGHTTIME
COOLING... HAVE ADJUSTED LOWS UP SLIGHTLY... TO 28-34.
FOR FRIDAY/FRIDAY NIGHT: THE NAM/GFS INDICATE A SHOT OF SHALLOW AND
MARGINALLY MOIST UPGLIDE AROUND 290K FRIDAY... SUGGESTIVE OF AREAS
OF STRATOCU THROUGH THE DAY... ALTHOUGH THE LATTER HOURS OF THE
LATEST RAP RUNS SHOW LESS IN THE WAY OF CLOUDS... AND THE NAM
DEPICTS LESS MOISTURE THAN THE GFS. EXPECT SKIES TO BE PARTLY CLOUDY
FOR MUCH OF THE DAY PARTICULARLY IN THE NORTH WHERE THE UPGLIDE
ITSELF IS STRONGER... ALTHOUGH PERIODS OF MOSTLY SUNNY SKIES ARE
EXPECTED ESPECIALLY IN THE SOUTH DURING THE EARLY TO MID AFTERNOON.
THE MODEL-PROJECTED LOW LEVEL THERMAL STRUCTURE SUPPORTS AN UPWARD
NUDGE TO FORECAST HIGHS... TO 61-67 WITH THE ONSET OF LOW LEVEL WARM
AIR ADVECTION AS WINDS BECOME SOUTHWESTERLY. MID AND HIGH CLOUDS NOW
OVER THE INTERIOR PACIFIC NORTHWEST ASSOCIATED WITH THE SURFACE
FRONTAL SYSTEM ARE EXPECTED TO OVERSPREAD THE REGION FROM MID-LATE
FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. WHILE THE LOW LEVELS ARE
LIKELY TO DECOUPLE WITH AN INCOMING 45-50 KT WRLY 850 MB JET MOVING
IN FROM THE WEST... I SUSPECT THAT FORECAST SOUNDINGS ARE SHOWING
SURFACE TEMPS THAT ARE TOO COOL BASED ON A STEADY SW BREEZE...
TIGHTENING MSLP GRADIENT... AND THE INCREASE AND THICKENING OF
CLOUDS. HAVE BROUGHT UP LOW TEMPS FRIDAY NIGHT TO 43-50... A BIT
ABOVE STATISTICAL GUIDANCE. -GIH
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 245 PM THURSDAY...
SATURDAY INTO SUNDAY...MODEL GUIDANCE HAS COME INTO BETTER AGREEMENT
FOR SATURDAY THROUGH EARLY SUNDAY...DRIFTING A SFC COLD FRONT SWD
INTO CENTRAL NC BY SATURDAY NIGHT...THEN STALLING THIS FEATURE
ACROSS THE SOUTHERN COUNTIES ON SUNDAY. AHEAD OF THIS FEATURE ON
SATURDAY...EXPECT WARM CONDITIONS AS THICKNESSES PROJECTED TO BE IN
THE 1370S...30-35M ABOVE NORMAL. THIS IS SUPPORTIVE OF TEMPS IN THE
70S. RH CROSS SECTIONS SUGGEST THAT UPPER LEVEL MOISTURE MAY BE
PLENTIFUL ENOUGH TO PRODUCE AN OPAQUE VEIL OF HIGH CLOUDS...ENOUGH
TO LIMIT INSOLATION. IF FULL SUN CONDITIONS WERE TO OCCUR...COULD
EASILY SEE TEMPS IN THE 75-80 DEGREE RANGE. SINCE BANKING ON SOME
DEGREE OF CLOUDINESS...FAVOR MAX TEMPS MORE IN THE LOW-MID 70S.
THREAT OF CONVECTION WILL EXIST SATURDAY AFTERNOON AND SATURDAY
NIGHT AS SFC FRONT DRIFTS SWD TOWARD AND INTO THE REGION. BEST
PARAMETERS FOR T-STORMS WILL BE SATURDAY AFTERNOON AS MID LEVEL
LAPSE RATES PROJECTED TO BE AROUND 7 DEG C/KM WITH SFC BASED CAPE IN
THE 500-1000J/KG RANGE...MAINLY ACROSS THE NORTH. PROJECTED BULK
SHEAR VALUES NOT TOO SHABBY WITH VALUES RANGING FROM 35-55KTS. THESE
PARAMETERS SUGGEST POTENTIAL FOR A FEW STRONG T-STORMS BUT LACK OF
LOW LEVEL INSTABILITY SHOULD LIMIT SEVERITY. WILL NEED TO MONITOR
LOW LEVEL CONDITIONS LEADING UP TO SATURDAY AFTERNOON-EVENING.
FOR SUNDAY...NOW APPEARS A LITTLE MORE LIKELY THAT A WEAK HYBRID
DAMMING EVENT MAY OCCUR ACROSS THE NORTH AS A WEAK, NARROW DRY AIR
RIDGE EXTENDS INTO THE NORTHERN COUNTIES. MEANWHILE SSW FLOW ALOFT
WILL SPREAD MOISTURE UP OVER THE STALLED FRONT ACROSS THE
SOUTH...SETTING UP THE POSSIBILITY OF AREAS OF LIGHT RAIN/DRIZZLE
ACROSS THE NORTH LATE SUNDAY INTO SUNDAY NIGHT. NONETHELESS...SHOULD
SEE A WIDE TEMP VARIANCE ACROSS THE FORECAST AREA WITH TEMPS NEAR
AND SOUTH OF THE BOUNDARY NEAR 70...WHILE TEMPS IN THE FAVORED
DAMMING REGION MAY HOLD IN THE 50S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 245 PM THURSDAY...
MONDAY...WILL LIKELY SEE A CONTINUANCE OF A WEAK CAD OR RESIDUAL CAD
AIR MASS OVER THE NORTHERN PIEDMONT AS STALLED BOUNDARY....DUE TO
LACK OF A MECHANISM TO PUSH BOUNDARY NWD UNTIL LATE...WILL LINGER
OVER THE SOUTH HALF OF THE FORECAST AREA. WILL STILL SEE A THREAT OF
RAIN ALONG AND NORTH OF THE BOUNDARY THOUGH APPEARS PRECIP WILL BE
SPARSE AND LIGHT IN INTENSITY. CLOUDS AND A COOL E-NE SFC FLOW WILL
KEEP TEMPS BELOW NORMAL ACROSS THE NORTH. MEANWHILE S-SW FLOW OVER
THE FAR SOUTH WILL RESULT IN ANOTHER DAY OF MILD TEMPS. MAX TEMPS
55-60 NORTH...NEAR 70 SOUTH.
MONDAY NIGHT AND TUESDAY...A SFC COLD FRONT ASSOCIATED WITH A S/W
TROUGH CROSSING THE GREAT LAKES WILL ADVANCE TOWARD CENTRAL NC
MONDAY NIGHT...AND CROSS THE PIEDMONT PRIOR TO DAYBREAK
TUESDAY...EXITING OUR COASTAL PLAIN COUNTIES PRIOR TO NOON. BEST MID
LEVEL CONFLUENCE AND UPPER LEVEL LIFT/SUPPORT OCCUR NORTH OF CENTRAL
NC. APPEARS THAT A RELATIVELY NARROW BAND OF SHOWERS WILL OCCUR
ALONG/AHEAD OF THE FRONT WITH RAPID DRYING/CLEARING OCCURRING
IMMEDIATELY BEHIND THE FRONT. THUS...APPEARS BEST CHANCE FOR RAIN
WILL OCCUR ACROSS THE WEST BETWEEN 06-12Z TUE...AND 09Z-15Z IN THE
EAST. STRONG CAA BEHIND FRONT BUT DOWNSLOPE COMPONENT TO LOW LEVEL
FLOW WILL OFFSET THE INITIAL SURGE OF COLD AIR. EXPECT MAX TEMPS
UPPER 50S NW TO LOW-MID 60S SE.
WEDNESDAY-THURSDAY...SENSIBLE WEATHER WILL BE DICTATED BY STRENGTH
OF UPPER TROUGH OVER THE NE U.S.. ECMWF DEEPER WITH THIS TROUGH WITH
THE PARENT LOW OVER SOUTHERN NEW ENGLAND. GFS NOT AS DEEP AND HAS
PARENT LOW FARTHER NORTH...OVER THE CANADIAN MARITIME. GFS ALLOWS
MINOR S/W RIDGE TO BUILD INTO THE SE U.S. RESULTING IN MILDER TEMPS
(COMPARED TO THE COLDER ECMWF). IT APPEARS THAT THE GFS IS TOO
PROGRESSIVE WITH THE UPSTREAM UPPER TROUGH MAKING ITS WAYS INTO THE
PACIFIC NW. THUS...WILL LEAN MORE TOWARD THE COLDER ECMWF SOLUTION.
VORTICITY MAXIMUM EMBEDDED IN THE NW FLOW ALOFT MAY CAUSE A PERIOD
OF CLOUDINESS THIS PERIOD BUT LACK OF MOISTURE FEED INTO THE REGION
SUGGEST LITTLE IF ANY CHANCES FOR APPRECIABLE PRECIPITATION.
EXISTENCE OF DEEP TROUGH SUGGEST TEMPS WELL BELOW NORMAL FOR MID
MARCH WITH AFTERNOON MAX TEMPS POSSIBLY AS MUCH AS 10-15 DEGREES
BELOW NORMAL (40S TO LOWER 50S). DO NOT PLAN TO GO THAT EXTREME THIS
FAR OUT. FAVOR MAX TEMPS 4-7 DEGREES BELOW NORMAL WED...AND 3-5
DEGREES BELOW THU.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 1235 PM THURSDAY...
HIGH CONFIDENCE IN VFR CONDITIONS HOLDING THROUGH FRIDAY... AS
SURFACE HIGH PRESSURE CENTERED OVER THE GULF COAST WILL CONTINUE TO
EXTEND INTO THE CAROLINAS. AN UPPER LEVEL DISTURBANCE NOW LOCATED
OVER THE MIDWEST WILL RAPIDLY DIVE TO THE SOUTHEAST... CROSSING GA
AND SC TONIGHT AND BRINGING MAINLY BKN MID AND HIGH CLOUDS TO
CENTRAL NC. CLOUD BASES ABOVE 12 THOUSAND FT AGL THIS EVENING WILL
DROP TO AROUND 6-7 THOUSAND FT AGL OVERNIGHT AND REMAIN THERE
THROUGH FRIDAY. WINDS FROM THE NW WILL DIMINISH LATE TODAY... REMAIN
LIGHT TONIGHT... THEN INCREASE OUT OF THE SOUTHWEST FRIDAY AFTERNOON
AT 12-16 KTS GUSTING TO 20-25 KTS.
LOOKING BEYOND 18Z FRIDAY... GUSTY SW WINDS WILL HOLD THROUGH THE
REST OF FRIDAY AFTERNOON. AS THE LOW LEVELS DECOUPLE AFTER SUNSET
AND SW WINDS STRENGTHEN ALOFT... LOW LEVEL WIND SHEAR IS LIKELY
FRIDAY NIGHT INTO EARLY SATURDAY. BREEZY AND GUSTY WINDS FROM THE
WSW ARE LIKELY THROUGH SATURDAY BUT WITH PREVAILING VFR CONDITIONS.
A BACKDOOR COLD FRONT WILL DROP IN FROM THE NORTH AND STALL OVER THE
REGION OVER THE WEEKEND... PRODUCING A GOOD CHANCE OF MVFR TO IFR
CONDITIONS FROM LATE SATURDAY NIGHT THROUGH MONDAY. THIS FRONT
SHOULD SHIFT NORTHWARD LATE MONDAY... WITH A TREND BACK TO BLUSTERY
SW WINDS AND VFR CONDITIONS... THEN A COLD FRONT PASSAGE MAY BRING A
BRIEF RETURN TO MVFR/IFR CONDITIONS IN SHOWERS ON TUESDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM..WSS
LONG TERM...WSS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
346 PM CDT THU MAR 14 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...
LATEST SURFACE ANALYSIS AND RAP 925MB TEMPS SHOWS A COLD FRONT
NOW ACROSS NORTHERN NORTH DAKOTA...FROM NEAR A TIOGA TO MINOT AND
RUGBY LINE. THERE IS A SHARP TRANSITION FROM TEMPERATURES IN THE 30S
JUST SOUTH OF THE FRONT TO TEENS AND 20S NORTH. THE GREATEST
WARMTH THIS AFTERNOON IS BEING FELT ACROSS THE SOUTHWEST WHERE
TEMPERATURES WILL CONTINUE TO RISE THROUGH THE 60S TO NEAR 70.
UTILIZED A MODEL BLEND OF THE NAM/GFS/RAP FOR MAXIMUM TEMPERATURES
ALOFT AND PRECIPITATION TYPES. THE MODELS DIFFER ON THE START TIME
ACROSS CENTRAL NORTH DAKOTA WITH GOOD AGREEMENT IN THE NORTH THIS
AFTERNOON THROUGH TONIGHT. BASICALLY THE TREND IS 90 TO 100 POPS
IN THE NORTH TONIGHT...MAINLY ALONG AND NORTH OF HIGHWAY 2 ARCHING
BACK INTO THE JAMES RIVER VALLEY. POPS WILL TAPER OFF SOUTH AND
WEST OF INTERSTATE 94. TOTAL SNOWFALL AMOUNTS IN THE WINTER
WEATHER ADVISORY OF 3 TO 6 INCHES STILL LOOKS ON TRACK. THERE
COULD BE ISOLATED POCKETS SLIGHTLY HIGHER THAN 6 INCHES IF ANY
HEAVY BANDING SNOW SETS UP ACROSS THE NORTH. THE NAM QPF AMOUNTS
ALONG AND NORTH OF HIGHWAY 2 ARE HIGHER THAN WHAT THE GFS/ECMWF
ARE ADVERTISING.
TEMPERATURES ALOFT SHOW THAT THERE COULD BE A QUICK TRANSITION
FROM LIGHT FREEZING RAIN TO SLEET AND SNOW FROM BISMARCK NORTH
AND EAST WHILE THE WARM POCKET ALOFT IS PUSHED WEST QUICKER.
SOUNDINGS SHOW THAT SLEET MAY BECOME COMMON WITH THE WARM POCKET
IN PLACE AND SURFACE TEMPS AT OR BELOW -6C FOR A PERIOD OF TIME.
THUS IN THE FREEZING RAIN ADVISORY...EXPECTING A MIX OF SLEET AND
SNOW TO OCCUR AND CHANGEOVER TO SNOW FRIDAY MORNING. SNOWFALL
ACCUMULATIONS IN THE FREEZING RAIN ADVISORY WILL RANGE FROM A
TRACE TO ONE INCH.
THE SNOW WILL TAPER OFF FRIDAY BUT CONTINUE FOR THE MAJORITY OF
THE DAY IN JAMES RIVER VALLEY BEFORE ENDING FRIDAY EVENING. MUCH
COLDER AIR IS FORECAST BEHIND THIS FRONT FOR FRIDAY WITH HIGHS
AROUND 10 IN THE FAR NORTH TO LOWER 50S FAR SOUTHWEST.
.LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
ACTIVE WINTER/SPRING WEATHER PATTERN FOR MUCH OF THE LONG TERM
FORECAST PERIOD.
WELL BELOW NORMAL TEMPERATURES ON SATURDAY IN THE WAKE OF A STRONG
UPPER LOW PUSHING EAST ACROSS SOUTHERN CANADA. 850MB TEMPS 00Z
SUNDAY ARE FORECAST TO RANGE FROM -20C OVER THE TURTLE MOUNTAINS TO
0C OVER THE EXTREME SOUTHWEST. THIS RESULTS IN HIGHS SATURDAY FROM
10F ABOVE OVER MY NORTHEAST TO AROUND 40F SOUTHWEST WHERE THE GROUND
REMAINS BARE. WILL MAINTAIN SLIGHT CHANCE POPS WEST NEAR THE
BAROCLINIC ZONE...WITH PRECIP TYPE DEPENDENT ON SFC TEMPERATURES.
WE WILL SLOWLY MODERATE OUR TEMPERATURES SATURDAY NIGHT AS RETURN
FLOW DEVELOPS...BUT STILL LOOKS TO BE COLD OVER THE TURTLE MOUNTAIN
REGION NEAR 10F BELOW ZERO. FARTHER SOUTHWEST...LOWS IN THE MID 20S
ARE FORECAST NEAR AN APPROACHING WARM FRONT. AS THE SFC HIGH MOVES
EAST SATURDAY NIGHT...THE BAROCLINIC ZONE ALSO SHIFTS EAST AND
RESULTS IN SLIGHT CHANCES FOR PRECIPITATION TO EXPAND INTO CENTRAL
PORTIONS OF THE STATE. WITH TEMPS ALOFT SUB-FREEZING...SHOULD SEE
MAINLY LIGHT SNOW.
MAIN ATTENTION IN THE LONG TERM PERIOD WILL BE ON THE TRACK OF A
STRONG S/WV MOVING INTO THE PACIFIC NORTHWEST SATURDAY
NIGHT...ADVECTING EAST ACROSS THE ROCKIES SUNDAY THEN LIFTING
THROUGH THE DAKOTAS SUNDAY NIGHT. 12Z GFS/ECMWF IN DECENT AGREEMENT
WITH WIDESPREAD QPF ACROSS WEST/CENTRAL NORTH DAKOTA SUNDAY MORNING
THROUGH SUNDAY EVENING...WITH THE MAIN PRECIP TYPE SNOW. MAX TEMP
ALOFT AROUND ZERO ACROSS THE SOUTH MAY RESULT IN A MIX SUNDAY
DAYTIME. WITH QPF AMOUNTS FROM A QUARTER TO NEAR THREE QUARTERS OF
AN INCH...POTENTIAL SNOW AMOUNTS WILL RANGE ANYWHERE FROM FOUR TO
EIGHT INCHES...POSSIBLY NEAR TEN. DID INCREASE PRECIP CHANCES TO
LIKELY BOTH SUNDAY AND SUNDAY NIGHT...BUT CANNOT STRESS ENOUGH THE
UNCERTAINTY OF HOW MUCH MOISTURE WILL ACTUALLY FALL. COULD BE
WIDESPREAD 3-7 INCH AMOUNTS IF THE ENERGY SPLITS...OR COULD SEE
HEAVY BANDED SNOW SOME AREAS IF MORE OF A COMPACT SYSTEM DEVELOPS.
WILL OF COURSE MONITOR CLOSELY AND MENTION THE POTENTIAL STORM IN
THE CURRENT WSW AND THE HWO WITH THIS FORECAST PACKAGE. ANOTHER
POTENTIAL HAZARD WITH THIS SYSTEM WILL BE STRONG WINDS...BOTH AHEAD
AND BEHIND THE SFC LOW. THIS WILL ALSO DEPEND ON WHETHER THE ENERGY
SPLITS OR NOT.
CHANCES FOR SNOW END MONDAY DAYTIME WEST TO EAST. BELOW NORMAL
TEMPERATURES WITH CAA IN THE WAKE OF THE S/WV.
NEXT BEST CHANCE FOR WIDESPREAD PRECIPITATION WILL COME LATER IN THE
WORK WEEK WHEN MODELS PROJECT ANOTHER UPPER LEVEL TROUGH MOVING EAST
ACROSS THE ROCKIES TOWARDS THE PLAINS. RIGHT NOW THE GFS AND THE
ECMWF DIFFER ON WHETHER THIS ENERGY NEGATIVELY TILTS OR MORPHS INTO
SPLIT FLOW.
&&
.AVIATION...IFR-LIFR STRATUS NOW OVER NORTHWEST AND NORTH CENTRAL
NORTH DAKOTA THIS AFTERNOON AS A FRONTAL BOUNDARY STARTS TO MOVE
SOUTH ACROSS THE STATE FROM CANADA. EXPECT CONDITIONS TO
DETERIORATE SOUTHWARD THIS EVENING AS THE FRONT CONTINUES SOUTH.
DO EXPECT SOME PERIODS OF MVFR-VFR TO INTERMINGLE WITH THE LOW
STRATUS INITIALLY NOW THROUGH MID EVENING...BUT SHOULD BE MAINLY
WIDESPREAD LATE EVENING THROUGH THE OVERNIGHT. A MIX OF
SNOW/SLEET/FREEZING RAIN LOOKS TO IMPACT KISN MID EVENING...AND
KBIS AFTER 06Z. THERE IS A SLIGHT CHANCE OF LIGHT FREEZING RAIN AT
KDIK TONIGHT THROUGH FRIDAY MORNING. MODERATE TO POSSIBLE PERIODS
OF HEAVY SNOW WILL IMPACT KMOT BEGINNING THIS EVENING WITH
CONDITIONS DETERIORATING OVERNIGHT THROUGH FRIDAY MORNING.
VISIBILITIES AT KMOT WILL LIKELY APPROACH AIRPORT MINIMUMS. FOR
KJMS...MAINLY SNOW IS EXPECTING...STARTING THIS EVENING AND
CONTINUING THROUGH FRIDAY MORNING WITH VISIBILITIES IN SNOW
FALLING TO IFR AND BELOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY FROM 1 AM CDT /MIDNIGHT MDT/ TO 10 AM CDT
/9 AM MDT/ FRIDAY FOR NDZ017>020-031>035-041-042-045>047-050-051.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 PM CDT
FRIDAY FOR NDZ001>005-009>013-021>023-025-036-037-048.
&&
$$
SHORT TERM...KS
LONG TERM/AVIATION...NH