Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/17/13
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1147 AM MDT MON APR 15 2013
.UPDATE...
ISSUED AT 1147 AM MDT MON APR 15 2013
VERY HEAVY SNOWFALL BEING REPORTED ALONG THE INTERSTATE 70
CORRIDOR FROM RIFLE EAST TO VAIL. CDOT HAS CLOSED PORTIONS OF THE
HIGHWAY DUE TO THE HEAVY SNOW AND REPORTS OF OVER 8 INCHES IN JUST
A FEW HOURS FROM THE GYPSUM AREA. HAVE ADDED ZONE 7...RIFLE
REGION...TO THE WINTER WEATHER ADVISORY AND UPGRADED ZONES 8 AND
10 TO WARNINGS TO DEAL WITH THIS HEAVY WET SNOW AND ENERGETIC
BAND. HAVE CONTINUED TO ADJUST TEMPS DOWNWARD AND ADJUSTED SNOW
LEVELS THROUGH THE REMAINDER OF THE DAY AS THE BAND REMAINS NEARLY
STATIONARY...WITH ALMOST A LIGHT NORTHWARD DRIFT EXPECTED OVER THE
NEXT FEW HOURS.
UPDATE ISSUED AT 912 AM MDT MON APR 15 2013
TEMPS REMAIN COLD ENOUGH ALONG THE INTERSTATE 70 CORRIDOR FROM THE
GLENWOOD CANYON EAST TO VAIL FOR HEAVY SNOW TO CONTINUE FOR A FEW
MORE HOURS. WEB CAMS AND SFC OBS INDICATE POOR CONDITIONS IN THIS
REGION AND ONLY MINOR IMPROVEMENT EXPECTED FOR THE NEXT SEVERAL
HOURS. RAP KEEPS THIS BAND ACTIVE THROUGH THIS AFTERNOON WITH
LITTLE MOVEMENT NORTH OR SOUTH AS THE JET. HAVE CONTINUED TO KNOCK
TEMPS BACK AND EXPAND COVERAGE OF SNOWFALL IN THIS REGION AND
BUMPED THE INTERSTATE 70 CORRIDOR INTO THE GROUPING OF WINTER
WEATHER ADVISORY. WOULD EXPECT A QUICK 2 TO 4 INCHES THIS
MORNING...FOLLOWED BY A MIXED OF RAIN/SNOW THIS AFTERNOON...WITH
ALL SNOW AGAIN TONIGHT.
UPDATE ISSUED AT 840 AM MDT MON APR 15 2013
HAVE UPGRADED ZONES 4 AND 13 TO WINTER STORM WARNINGS THROUGH
EARLY TUESDAY MORNING. BAND OF HEAVIER SNOWFALL WILL CONTINUE TO
IMPACT THE SOUTHERN PORTIONS OF THESE ZONES THROUGH THIS
MORNING...WITH ACTIVITY DIMINISHING A BIT THIS AFTERNOON...BEFORE
THE BAND LIFTS BACK NORTH TONIGHT...PER LATEST RAP RUN. SNOTELS
GENERALLY IN THE 2 TO 6 INCH RANGE SO FAR AND ANTICIPATE LOW END
WARNING LEVELS TO HIT BY LATE TONIGHT. SPOTTER REPORTS IN THE
VICINITY OF STEAMBOAT SPRINGS AND WEB CAMS INDICATE SNOWFALL
APPROACHING ADVISORY LEVELS AND MOST ROADWAYS IN THE AREA REMAIN
ICY AND SNOW PACKED. MADE SOME ADJUSTMENTS TO TEMPS AND BOOSTED
SNOWFALL AMOUNTS THROUGH LATE TONIGHT IN THE STEAMBOAT SPRINGS
AREA AND ALSO UPGRADED THEM TO AN ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
ANOTHER CHALLENGING STORM GREETS THE NEW WORKWEEK. SNOW HAS
INCREASED ACROSS NE UT/NW CO EARLY THIS MORNING IN ISENTROPIC AND
DYNAMIC UPLIFT AHEAD OF THE NEXT SHORTWAVE/UPPER JET MAX. 400 AM
WEB CAM PICS INDICATED GROUND WARMTH KEEPING ROADS WET AT VERNAL THOUGH
AIR TEMPS HAVE DROPPED BELOW FREEZING...AND SNOW WAS JUST BEGINNING
TO STICK TO THE PAVEMENT AT STEAMBOAT. BOTH NAM AND GFS SHOW A GOOD
COMBINATION OF UPPER DIVERGENCE... FRONTOGENETIC FORCING ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE AT 700 MB...AND MOIST ISENTROPIC
UPGLIDE THROUGH THE MORNING ACROSS THE NORTH. TIME-HEIGHT SECTIONS
OF -PVU ALSO INDICATE THE POSSIBLY OF SOME BANDED PRECIPITATION FOR
LOCALLY HEAVIER PRECIP...JUST DIFFICULT TO PINPOINT EXACTLY WHERE.
RAPID REFRESH MODEL SHOWED PRECIP TAPERING OFF IN THE NORTHERN
VALLEYS LATER THIS MORNING...BUT WILL STILL HAVE MONITOR SNOW
ACCUMULATION FOR THESE NORTHERN VALLEYS AS SOME LOWER ELEVATION
LOCATIONS MAY SEE A COUPLE INCHES BEFORE TEMPS WARM SUFFICIENTLY.
MAIN CHALLENGE TODAY THROUGH TUESDAY IS SNOW ACCUMS AND LOCATION OF
THE HEAVIER AMTS. BEST PERIOD MAY BE TODAY GIVEN THE COMBINATION OF
FORCING PREVIOUSLY MENTIONED...BUT SOME UNCERTAINTY IN LOCATION WITH
THE NAM FAVORING THE NRN MTNS WHILE THE GFS MORE THE CENTRAL MTNS.
FOR CO ZONE 4 /ELKHEAD AND PARK MTNS/ FLOW TURNS FROM WESTERLY TO
LESS FAVORABLE SOUTHERLY TONIGHT IN RESPONSE TO A DEEPENING TROUGH
OVER NEVADA...BUT CONTINUED DYNAMIC AND ISENTROPIC FORCING SHOULD
COMPENSATE SOMEWHAT. WILL KEEP THE CURRENT WINTER WEATHER ADVISORIES
FOR THE NORTHERN AND CENTRAL MTNS INTACT THOUGH DAY SHIFT WILL HAVE
TO MONITOR FOR ANY UPGRADE TO WARNING.
AS PACIFIC ENERGY OFF THE WA/OR COAST DEVELOP A COLD TROUGH OVER THE
GREAT BASIN BY TUESDAY AFTERNOON...THE UPPER JET AND BAROCLINIC ZONE
ACROSS THE NORTH SHOULD ROTATE COUNTERCLOCKWISE...WITH THE PIVOT
POINT NEAR NE UT. SURFACE LOW DEVELOPS OVER SE UT TUE MORNING AND
SHIFTS INTO SW CO TUE AFTERNOON AS 700 MB LOW MOVES OVER NE UT.
DRYING IS NOT AS PRONOUNCED IN THE WARM SECTOR ACROSS WRN CO AS
EARLIER MODELS INDICATED...SO WILL KEEP SCATTERED TO NUMEROUS
SHOWERS ACROSS THE NORTH BUT WITH LESSER ACCUMULATIONS.
GUSTY WINDS ARE EXPECTED ACROSS SE UT/SW CO TODAY AND TUESDAY. GUSTS
UP TO 40 MPH ARE POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
STRONGEST DEEP LAYERED ASCENT OCCURS TUESDAY NIGHT INTO WEDNESDAY
MORNING ACROSS THE ENTIRE FORECAST AREA...BUT THE BEST QG FORCING
WILL BE CENTERED OVER THE NORTHEAST PORTION OF THE FORECAST AREA.
FAIRLY STRONG MID LEVEL COLD ADVECTION WHERE 700 MB TEMPS BECOME
COLDER THAN -10C ON THE BACK SIDE OF THE TROUGH...SUGGESTING THAT
SNOW PRODUCTION BECOMES MORE EFFICIENT AS THE COLDER SPREADS ACROSS
THE WRN SLOPE. DEEP COLD TROUGH IS MORE ELONGATED...AND THIS IS A
FORECAST CONCERN AS THE OROGRAPHIC COMPONENT WILL BE LESS FAVORABLE
(BECOMING NORTHERLY INSTEAD OF THE PREFERRED POST FRONTAL NORTHWEST
FLOW). ONE STRONG PLUS IS THE 700 MB LOW MOVES ACROSS WRN COLORADO
WITH GOOD MOISTURE CONVERGENCE...AND THAT WILL LEAD TO ROBOST
SNOWFALL RATES AS THE FRONT MOVES ACROSS THE AREA. WILL HOIST A
WINTER STORM WATCH FOR TUESDAY NIGHT THROUGH WEDNESDAY FOR THE WRN
COLORADO HIGH COUNTRY...ALTHOUGH CONFIDENCE IS ONLY 50/50 GIVEN THE
AFOREMENTIONED TROUGH STRUCTURE. THIS COULD EVOLVE INTO THE TYPE OF
STORM WHERE ONE LOCATION RECEIVES A HEALTHY DOSE OF SNOW...AND A FEW
MILES AWAY WITH DIFFERENT TERRAIN GETS SKUNKED. DAGGETT COUNTY IS
ONE AREA THAT COULD RECEIVE HEAVY AMOUNTS...AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING THE WINTER WEATHER ADVISORY TO A
WARNING. THE UNCOMPAHGRE GORGE IS ANOTHER LOCATION THAT MAY BE
ANOTHER TROUBLE SPOT.
MOISTURE DROPS OFF FAIRLY QUICKLY THURSDAY NIGHT AS THE MAIN UPPER
LOW MOVES INTO THE CENTRAL PLAINS. LIGHT OROGRAPHIC SNOW MAY LINGER
TOWARD THE DIVIDE...OTHERWISE CLEARING CONDITIONS FROM THE WEST.
FROSTY CONDITIONS WITH WELL BELOW NORMAL TEMPS THAT POSE A THREAT TO
SENSITIVE VEGETATION.
FRIDAY THROUGH SUNDAY...NORTHWEST FLOW PREVAILS WITH EMBEDDED
PROGRESSIVE SHORT WAVES. ONE FAST MOVING WAVE SKIRTS THE NRN DIVIDE
ON FRIDAY...BUT THE STRONGEST OPEN WAVE SPREADS DECENT PACIFIC
MOISTURE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY AND HAS THE
POTENTIAL TO DROP SEVERAL INCHES OF SNOW OVER THE NRN MOUNTAINS.
OTHERWISE TEMPS WILL BE MODERATING THIS WEEKEND AND SLOWLY CLIMB TO
NEAR CLIMO BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED
AT 912 AM MDT MON APR 15 2013
IFR CONDITIONS IN -SN/SN AND BR WILL BE WIDESPREAD FROM I-70
NORTHWARD THROUGH TONIGHT. THIS INCLUDES KVEL...KRIL...KEGE AND
KASE. THE CENTRAL AND SOUTHERN MOUNTAINS WILL BE OCCASIONALLY OBSCURED
IN -SN. EXPECTED DEGRADED FLIGHT CONDITIONS FOR THE NORTH AND
CENTRAL AREAS THROUGH 18Z TUE. STRONG GUSTY WINDS WILL HAMPER
AVIATION OPERATIONS IN SE UT AND SW CO THIS AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MDT TUESDAY FOR COZ003-005-
007-009-012.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR COZ003-004-009-010-012-013-018.
WINTER STORM WARNING UNTIL 9 AM MDT TUESDAY FOR COZ004-008-010-
013.
UT...WINTER WEATHER ADVISORY UNTIL 6 PM MDT WEDNESDAY FOR UTZ023.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
914 AM MDT MON APR 15 2013
.UPDATE...
ISSUED AT 912 AM MDT MON APR 15 2013
TEMPS REMAIN COLD ENOUGH ALONG THE INTERSTATE 70 CORRIDOR FROM THE
GLENWOOD CANYON EAST TO VAIL FOR HEAVY SNOW TO CONTINUE FOR A FEW
MORE HOURS. WEB CAMS AND SFC OBS INDICATE POOR CONDITIONS IN THIS
REGION AND ONLY MINOR IMPROVEMENT EXPECTED FOR THE NEXT SEVERAL
HOURS. RAP KEEPS THIS BAND ACTIVE THROUGH THIS AFTERNOON WITH
LITTLE MOVEMENT NORTH OR SOUTH AS THE JET. HAVE CONTINUED TO KNOCK
TEMPS BACK AND EXPAND COVERAGE OF SNOWFALL IN THIS REGION AND
BUMPED THE INTERSTATE 70 CORRIDOR INTO THE GROUPING OF WINTER
WEATHER ADVISORY. WOULD EXPECT A QUICK 2 TO 4 INCHES THIS
MORNING...FOLLOWED BY A MIXED OF RAIN/SNOW THIS AFTERNOON...WITH
ALL SNOW AGAIN TONIGHT.
UPDATE ISSUED AT 840 AM MDT MON APR 15 2013
HAVE UPGRADED ZONES 4 AND 13 TO WINTER STORM WARNINGS THROUGH
EARLY TUESDAY MORNING. BAND OF HEAVIER SNOWFALL WILL CONTINUE TO
IMPACT THE SOUTHERN PORTIONS OF THESE ZONES THROUGH THIS
MORNING...WITH ACTIVITY DIMINISHING A BIT THIS AFTERNOON...BEFORE
THE BAND LIFTS BACK NORTH TONIGHT...PER LATEST RAP RUN. SNOTELS
GENERALLY IN THE 2 TO 6 INCH RANGE SO FAR AND ANTICIPATE LOW END
WARNING LEVELS TO HIT BY LATE TONIGHT. SPOTTER REPORTS IN THE
VICINITY OF STEAMBOAT SPRINGS AND WEB CAMS INDICATE SNOWFALL
APPROACHING ADVISORY LEVELS AND MOST ROADWAYS IN THE AREA REMAIN
ICY AND SNOW PACKED. MADE SOME ADJUSTMENTS TO TEMPS AND BOOSTED
SNOWFALL AMOUNTS THROUGH LATE TONIGHT IN THE STEAMBOAT SPRINGS
AREA AND ALSO UPGRADED THEM TO AN ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
ANOTHER CHALLENGING STORM GREETS THE NEW WORKWEEK. SNOW HAS
INCREASED ACROSS NE UT/NW CO EARLY THIS MORNING IN ISENTROPIC AND
DYNAMIC UPLIFT AHEAD OF THE NEXT SHORTWAVE/UPPER JET MAX. 400 AM
WEB CAM PICS INDICATED GROUND WARMTH KEEPING ROADS WET AT VERNAL THOUGH
AIR TEMPS HAVE DROPPED BELOW FREEZING...AND SNOW WAS JUST BEGINNING
TO STICK TO THE PAVEMENT AT STEAMBOAT. BOTH NAM AND GFS SHOW A GOOD
COMBINATION OF UPPER DIVERGENCE... FRONTOGENETIC FORCING ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE AT 700 MB...AND MOIST ISENTROPIC
UPGLIDE THROUGH THE MORNING ACROSS THE NORTH. TIME-HEIGHT SECTIONS
OF -PVU ALSO INDICATE THE POSSIBLY OF SOME BANDED PRECIPITATION FOR
LOCALLY HEAVIER PRECIP...JUST DIFFICULT TO PINPOINT EXACTLY WHERE.
RAPID REFRESH MODEL SHOWED PRECIP TAPERING OFF IN THE NORTHERN
VALLEYS LATER THIS MORNING...BUT WILL STILL HAVE MONITOR SNOW
ACCUMULATION FOR THESE NORTHERN VALLEYS AS SOME LOWER ELEVATION
LOCATIONS MAY SEE A COUPLE INCHES BEFORE TEMPS WARM SUFFICIENTLY.
MAIN CHALLENGE TODAY THROUGH TUESDAY IS SNOW ACCUMS AND LOCATION OF
THE HEAVIER AMTS. BEST PERIOD MAY BE TODAY GIVEN THE COMBINATION OF
FORCING PREVIOUSLY MENTIONED...BUT SOME UNCERTAINTY IN LOCATION WITH
THE NAM FAVORING THE NRN MTNS WHILE THE GFS MORE THE CENTRAL MTNS.
FOR CO ZONE 4 /ELKHEAD AND PARK MTNS/ FLOW TURNS FROM WESTERLY TO
LESS FAVORABLE SOUTHERLY TONIGHT IN RESPONSE TO A DEEPENING TROUGH
OVER NEVADA...BUT CONTINUED DYNAMIC AND ISENTROPIC FORCING SHOULD
COMPENSATE SOMEWHAT. WILL KEEP THE CURRENT WINTER WEATHER ADVISORIES
FOR THE NORTHERN AND CENTRAL MTNS INTACT THOUGH DAY SHIFT WILL HAVE
TO MONITOR FOR ANY UPGRADE TO WARNING.
AS PACIFIC ENERGY OFF THE WA/OR COAST DEVELOP A COLD TROUGH OVER THE
GREAT BASIN BY TUESDAY AFTERNOON...THE UPPER JET AND BAROCLINIC ZONE
ACROSS THE NORTH SHOULD ROTATE COUNTERCLOCKWISE...WITH THE PIVOT
POINT NEAR NE UT. SURFACE LOW DEVELOPS OVER SE UT TUE MORNING AND
SHIFTS INTO SW CO TUE AFTERNOON AS 700 MB LOW MOVES OVER NE UT.
DRYING IS NOT AS PRONOUNCED IN THE WARM SECTOR ACROSS WRN CO AS
EARLIER MODELS INDICATED...SO WILL KEEP SCATTERED TO NUMEROUS
SHOWERS ACROSS THE NORTH BUT WITH LESSER ACCUMULATIONS.
GUSTY WINDS ARE EXPECTED ACROSS SE UT/SW CO TODAY AND TUESDAY. GUSTS
UP TO 40 MPH ARE POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
STRONGEST DEEP LAYERED ASCENT OCCURS TUESDAY NIGHT INTO WEDNESDAY
MORNING ACROSS THE ENTIRE FORECAST AREA...BUT THE BEST QG FORCING
WILL BE CENTERED OVER THE NORTHEAST PORTION OF THE FORECAST AREA.
FAIRLY STRONG MID LEVEL COLD ADVECTION WHERE 700 MB TEMPS BECOME
COLDER THAN -10C ON THE BACK SIDE OF THE TROUGH...SUGGESTING THAT
SNOW PRODUCTION BECOMES MORE EFFICIENT AS THE COLDER SPREADS ACROSS
THE WRN SLOPE. DEEP COLD TROUGH IS MORE ELONGATED...AND THIS IS A
FORECAST CONCERN AS THE OROGRAPHIC COMPONENT WILL BE LESS FAVORABLE
(BECOMING NORTHERLY INSTEAD OF THE PREFERRED POST FRONTAL NORTHWEST
FLOW). ONE STRONG PLUS IS THE 700 MB LOW MOVES ACROSS WRN COLORADO
WITH GOOD MOISTURE CONVERGENCE...AND THAT WILL LEAD TO ROBOST
SNOWFALL RATES AS THE FRONT MOVES ACROSS THE AREA. WILL HOIST A
WINTER STORM WATCH FOR TUESDAY NIGHT THROUGH WEDNESDAY FOR THE WRN
COLORADO HIGH COUNTRY...ALTHOUGH CONFIDENCE IS ONLY 50/50 GIVEN THE
AFOREMENTIONED TROUGH STRUCTURE. THIS COULD EVOLVE INTO THE TYPE OF
STORM WHERE ONE LOCATION RECEIVES A HEALTHY DOSE OF SNOW...AND A FEW
MILES AWAY WITH DIFFERENT TERRAIN GETS SKUNKED. DAGGETT COUNTY IS
ONE AREA THAT COULD RECEIVE HEAVY AMOUNTS...AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING THE WINTER WEATHER ADVISORY TO A
WARNING. THE UNCOMPAHGRE GORGE IS ANOTHER LOCATION THAT MAY BE
ANOTHER TROUBLE SPOT.
MOISTURE DROPS OFF FAIRLY QUICKLY THURSDAY NIGHT AS THE MAIN UPPER
LOW MOVES INTO THE CENTRAL PLAINS. LIGHT OROGRAPHIC SNOW MAY LINGER
TOWARD THE DIVIDE...OTHERWISE CLEARING CONDITIONS FROM THE WEST.
FROSTY CONDITIONS WITH WELL BELOW NORMAL TEMPS THAT POSE A THREAT TO
SENSITIVE VEGETATION.
FRIDAY THROUGH SUNDAY...NORTHWEST FLOW PREVAILS WITH EMBEDDED
PROGRESSIVE SHORT WAVES. ONE FAST MOVING WAVE SKIRTS THE NRN DIVIDE
ON FRIDAY...BUT THE STRONGEST OPEN WAVE SPREADS DECENT PACIFIC
MOISTURE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY AND HAS THE
POTENTIAL TO DROP SEVERAL INCHES OF SNOW OVER THE NRN MOUNTAINS.
OTHERWISE TEMPS WILL BE MODERATING THIS WEEKEND AND SLOWLY CLIMB TO
NEAR CLIMO BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED
AT 912 AM MDT MON APR 15 2013
IFR CONDITIONS IN -SN/SN AND BR WILL BE WIDESPREAD FROM I-70
NORTHWARD THROUGH TONIGHT. THIS INCLUDES KVEL...KRIL...KEGE AND
KASE. THE CENTRAL AND SOUTHERN MOUNTAINS WILL BE OCCASIONALLY OBSCURED
IN -SN. EXPECTED DEGRADED FLIGHT CONDITIONS FOR THE NORTH AND
CENTRAL AREAS THROUGH 18Z TUE. STRONG GUSTY WINDS WILL HAMPER
AVIATION OPERATIONS IN SE UT AND SW CO THIS AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MDT TUESDAY FOR COZ005-
008>010-012.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR COZ003-004-009-010-012-013-018.
WINTER STORM WARNING UNTIL 9 AM MDT TUESDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL 6 PM MDT WEDNESDAY FOR UTZ023.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
840 AM MDT MON APR 15 2013
.UPDATE...
ISSUED AT 840 AM MDT MON APR 15 2013
HAVE UPGRADED ZONES 4 AND 13 TO WINTER STORM WARNINGS THROUGH
EARLY TUESDAY MORNING. BAND OF HEAVIER SNOWFALL WILL CONTINUE TO
IMPACT THE SOUTHERN PORTIONS OF THESE ZONES THROUGH THIS
MORNING...WITH ACTIVITY DIMINISHING A BIT THIS AFTERNOON...BEFORE
THE BAND LIFTS BACK NORTH TONIGHT...PER LATEST RAP RUN. SNOTELS
GENERALLY IN THE 2 TO 6 INCH RANGE SO FAR AND ANTICIPATE LOW END
WARNING LEVELS TO HIT BY LATE TONIGHT. SPOTTER REPORTS IN THE
VICINITY OF STEAMBOAT SPRINGS AND WEB CAMS INDICATE SNOWFALL
APPROACHING ADVISORY LEVELS AND MOST ROADWAYS IN THE AREA REMAIN
ICY AND SNOWPACKED. MADE SOME ADJUSTMENTS TO TEMPS AND BOOSTED
SNOWFALL AMOUNTS THROUGH LATE TONIGHT IN THE STEAMBOAT SPRINGS
AREA AND ALSO UPGRADED THEM TO AN ADVISORY.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
ANOTHER CHALLENGING STORM GREETS THE NEW WORKWEEK. SNOW HAS
INCREASED ACROSS NE UT/NW CO EARLY THIS MORNING IN ISENTROPIC AND
DYNAMIC UPLIFT AHEAD OF THE NEXT SHORTWAVE/UPPER JET MAX. 400 AM
WEBCAM PICS INDICATED GROUND WARMTH KEEPING ROADS WET AT VERNAL THOUGH
AIR TEMPS HAVE DROPPED BELOW FREEZING...AND SNOW WAS JUST BEGINNING
TO STICK TO THE PAVEMENT AT STEAMBOAT. BOTH NAM AND GFS SHOW A GOOD
COMBINATION OF UPPER DIVERGENCE... FRONTOGENETIC FORCING ALONG AN
EAST-WEST ORIENTED BAROCLINIC ZONE AT 700 MB...AND MOIST ISENTROPIC
UPGLIDE THROUGH THE MORNING ACROSS THE NORTH. TIME-HEIGHT SECTIONS
OF -PVU ALSO INDICATE THE POSSIBLY OF SOME BANDED PRECIPITATION FOR
LOCALLY HEAVIER PRECIP...JUST DIFFICULT TO PINPOINT EXACTLY WHERE.
RAPID REFRESH MODEL SHOWED PRECIP TAPERING OFF IN THE NORTHERN
VALLEYS LATER THIS MORNING...BUT WILL STILL HAVE MONITOR SNOW
ACCUMULATION FOR THESE NORTHERN VALLEYS AS SOME LOWER ELEVATION
LOCATIONS MAY SEE A COUPLE INCHES BEFORE TEMPS WARM SUFFICIENTLY.
MAIN CHALLENGE TODAY THROUGH TUESDAY IS SNOW ACCUMS AND LOCATION OF
THE HEAVIER AMTS. BEST PERIOD MAY BE TODAY GIVEN THE COMBINATION OF
FORCING PREVIOUSLY MENTIONED...BUT SOME UNCERTAINTY IN LOCATION WITH
THE NAM FAVORING THE NRN MTNS WHILE THE GFS MORE THE CENTRAL MTNS.
FOR CO ZONE 4 /ELKHEAD AND PARK MTNS/ FLOW TURNS FROM WESTERLY TO
LESS FAVORABLE SOUTHERLY TONIGHT IN RESPONSE TO A DEEPENING TROUGH
OVER NEVADA...BUT CONTINUED DYNAMIC AND ISENTROPIC FORCING SHOULD
COMPENSATE SOMEWHAT. WILL KEEP THE CURRENT WINTER WEATHER ADVISORIES
FOR THE NORTHERN AND CENTRAL MTNS INTACT THOUGH DAYSHIFT WILL HAVE
TO MONITOR FOR ANY UPGRADE TO WARNING.
AS PACIFIC ENERGY OFF THE WA/OR COAST DEVELOP A COLD TROUGH OVER THE
GREAT BASIN BY TUESDAY AFTERNOON...THE UPPER JET AND BAROCLINIC ZONE
ACROSS THE NORTH SHOULD ROTATE COUNTERCLOCKWISE...WITH THE PIVOT
POINT NEAR NE UT. SURFACE LOW DEVELOPS OVER SE UT TUE MORNING AND
SHIFTS INTO SW CO TUE AFTERNOON AS 700 MB LOW MOVES OVER NE UT.
DRYING IS NOT AS PRONOUNCED IN THE WARM SECTOR ACROSS WRN CO AS
EARLIER MODELS INDICATED...SO WILL KEEP SCATTERED TO NUMEROUS
SHOWERS ACROSS THE NORTH BUT WITH LESSER ACCUMULATIONS.
GUSTY WINDS ARE EXPECTED ACROSS SE UT/SW CO TODAY AND TUESDAY. GUSTS
UP TO 40 MPH ARE POSSIBLE.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 507 AM MDT MON APR 15 2013
STRONGEST DEEP LAYERED ASCENT OCCURS TUESDAY NIGHT INTO WEDNESDAY
MORNING ACROSS THE ENTIRE FORECAST AREA...BUT THE BEST QG FORCING
WILL BE CENTERED OVER THE NORTHEAST PORTION OF THE FORECAST AREA.
FAIRLY STRONG MID LEVEL COLD ADVECTION WHERE 700 MB TEMPS BECOME
COLDER THAN -10C ON THE BACK SIDE OF THE TROUGH...SUGGESTING THAT
SNOW PRODUCTION BECOMES MORE EFFICIENT AS THE COLDER SPREADS ACROSS
THE WRN SLOPE. DEEP COLD TROUGH IS MORE ELONGATED...AND THIS IS A
FORECAST CONCERN AS THE OROGRAPHIC COMPONENT WILL BE LESS FAVORABLE
(BECOMING NORTHERLY INSTEAD OF THE PREFERRED POST FRONTAL NORTHWEST
FLOW). ONE STRONG PLUS IS THE 700 MB LOW MOVES ACROSS WRN COLORADO
WITH GOOD MOISTURE CONVERGENCE...AND THAT WILL LEAD TO ROBOST
SNOWFALL RATES AS THE FRONT MOVES ACROSS THE AREA. WILL HOIST A
WINTER STORM WATCH FOR TUESDAY NIGHT THROUGH WEDNESDAY FOR THE WRN
COLORADO HIGH COUNTRY...ALTHOUGH CONFIDENCE IS ONLY 50/50 GIVEN THE
AFOREMENTIONED TROUGH STRUCTURE. THIS COULD EVOLVE INTO THE TYPE OF
STORM WHERE ONE LOCATION RECEIVES A HEALTHY DOSE OF SNOW...AND A FEW
MILES AWAY WITH DIFFERENT TERRAIN GETS SKUNKED. DAGGETT COOUNTY IS
ONE AREA THAT COULD RECEIVE HEAVY AMOUNTS...AND LATER SHIFTS MAY
NEED TO CONSIDER UPGRADING THE WINTER WEATHER ADVISORY TO A
WARNING. THE UNCOMPAHGRE GORGE IS ANOTHER LOCATION THAT MAY BE
ANOTHER TROUBLE SPOT.
MOISTURE DROPS OFF FAIRLY QUICKLY THURSDAY NIGHT AS THE MAIN UPPER
LOW MOVES INTO THE CENTRAL PLAINS. LIGHT OROGRAPHIC SNOW MAY LINGER
TOWARD THE DIVIDE...OTHERWISE CLEARING CONDITIONS FROM THE WEST.
FROSTY CONDITIONS WITH WELL BELOW NORMAL TEMPS THAT POSE A THREAT TO
SENSITIVE VEGETATION.
FRIDAY THROUGH SUNDAY...NORTHWEST FLOW PREVAILS WITH EMBEDDED
PROGRESSIVE SHORT WAVES. ONE FAST MOVING WAVE SKIRTS THE NRN DIVIDE
ON FRIDAY...BUT THE STRONGEST OPEN WAVE SPREADS DECENT PACIFIC
MOISTURE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY AND HAS THE
POTENTIAL TO DROP SEVERAL INCHES OF SNOW OVER THE NRN MOUNTAINS.
OTHERWISE TEMPS WILL BE MODERATING THIS WEEKEND AND SLOWLY CLIMB TO
NEAR CLIMO BY SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 507 AM MDT MON APR 15 2013
IFR CONDITIONS IN -SN/SN AND BR WILL BE WIDESPREAD FROM I-70
NORTHWARD THIS MORNING WITH MOUNTAINS OBSCURED. THIS INCLUDES
KVEL...KRIL...KEGE AND KASE. SOME IMPROVEMENT IS EXPECTED BY
MIDDAY...BUT -SHSN/-SHRA THROUGH THE AFTERNOON WILL CONTINUE. THE
CENTRAL AND SOUTHERN MOUNTAINS WILL BE OCCASIONALLY BE OBSCURED IN
-SN. EXPECTED DEGRADED FLIGHT CONDITIONS FOR THE NORTH AND CENTRAL
AREAS THROUGH 12Z TUE. STRONG GUSTY WINDS WILL HAMPER AVIATION
OPERATIONS IN SE UT AND SW CO THIS AFTERNOON.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MDT TUESDAY FOR COZ005-009-
010-012.
WINTER STORM WATCH FROM TUESDAY EVENING THROUGH WEDNESDAY
AFTERNOON FOR COZ003-004-009-010-012-013-018.
WINTER STORM WARNING UNTIL 9 AM MDT TUESDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL 6 PM MDT WEDNESDAY FOR UTZ023.
&&
$$
UPDATE...JDC
SHORT TERM...JAD
LONG TERM...PF
AVIATION...JAD
AREA FORECAST DISCUSSION
NWS ALBANY NY
954 PM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE SOUTH OF THE REGION THIS
EVENING. HIGH PRESSURE WILL BRIEFLY BUILD IN FROM THE NORTH WITH
FAIR AND DRY WEATHER FOR WEDNESDAY. THE COLD FRONT WILL LIFT BACK
NORTHWARD AS A WARM FRONT WEDNESDAY NIGHT INTO THURSDAY WITH
ISOLATED TO SCATTERED SHOWERS AND A RETURN TO MILDER WEATHER.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 930 PM EDT...CURRENT FORECAST REMAINS ON TRACK AND HAVE MADE
ADJUSTMENTS TO TEMPS AND POPS TO ACCOUNT FOR LATEST OBSERVATIONS.
SHOWERS ASSOCIATED WITH A COLD FRONT NOW PROGRESSING THROUGH WESTERN
NEW YORK CONTINUE TO IMPACT THE FORECAST AREA WITH MOST LOCATIONS
SEEING GENERALLY AROUND A TENTH OF AN INCH OF ACCUMULATION.
RADAR TRENDS CONTINUE TO DEPICT AN OVERALL WEAKENING TREND WITH THE
SHOWER ACTIVITY AS IT MOVES EASTWARD ACROSS THE FORECAST AREA...WITH
THE BEST ORGANIZATION PRIMARILY NORTH OF THE GREATER CAPITAL
DISTRICT. THESE SHOWERS WILL GRADUALLY WEAKEN THROUGH TIME AS THEY
RACE AHEAD OF THE COLD FRONT. SOME BRIEF GUSTY WINDS MAY ACCOMPANY
ANY HEAVIER SHOWERS...ESPECIALLY IN NORTHERN PORTIONS OF THE
FORECAST AREA.
SEE PREVIOUS DISCUSSION BELOW...
AS OF 730 PM EDT...REINVIGORATED BAND OF SHOWERS HAS FORMED AHEAD OF
AND IMMEDIATELY ALONG A COLD FRONT NOW BEGINNING TO MOVE THROUGH
WESTERN NEW YORK. MUCH OF THE MODEL GUIDANCE HAS CONTINUED TO SHOW A
MORE PROGRESSIVE FRONTAL PASSAGE...HOWEVER THE HRRR SEEMS TO BE THE
CLOSEST IN AGREEMENT WITH CURRENT OBSERVATIONS....WHICH WOULD DEPICT
THE COLD FRONT CROSSING THE FORECAST AREA IN THE 06-09Z TIMEFRAME.
HAVE MADE ADJUSTMENTS TO POPS IN GRIDS TO ACCOUNT FOR THIS TIMING.
BEHIND THE COLD FRONT...HIGH PRESSURE OVER NORTHERN-CENTRAL
CANADA WILL BEGIN TO EXTEND ITS INFLUENCES ACROSS THE GREAT LAKES
REGION AND INTO NEW ENGLAND LATE TONIGHT. THIS WILL ALLOW FOR
PARTIAL CLEARING SKIES FROM NORTH TO SOUTH. BASED ON UPSTREAM
TEMPERATURES...WILL FAVOR A BLEND OF MOS GUIDANCE WITH PERHAPS ON
THE COOLER SIDE NORTH OF I90 WHERE SKIES MAY CLEAR FOR A PERIOD OF
TIME BEFORE SUNRISE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY...THE FRONTAL BOUNDARY BECOMES QUASI-STATIONARY OVER
THE I80 CORRIDOR WITH THAT LARGE SURFACE HIGH EXTENDING ITS
INFLUENCES OVER THE NORTHEAST CORRIDOR OF THE CONUS. MOSTLY
SUNNY AND DRY CONDITIONS ARE EXPECTED WITH DECENT MIXING /A FEW
MORE CLOUDS ARE EXPECTED SOUTH OF I90/ AS TEMPERATURES SHOULD AVERAGE
AROUND 60F TO MID 60S IN THE VALLEYS...AND 50S MAINLY OVER THE MTNS
/A FEW U40S OVER THE DACKS AND SOUTHERN GREENS/.
WEDNESDAY NIGHT...AS THE SURFACE HIGH SLIDES NORTHEAST OF THE
REGION...A POTENT STORM TAKES SHAPE ACROSS THE CENTER OF THE
NATION. THIS WILL SET UP AN INCREASING SOUTHERLY FLOW OF WARMER
AND MORE MOIST AIR INTO THE REGION WITH THE PASSAGE OF A WARM
FRONT. THERE ARE INCREASING HINTS THAT THE LOWER LEVEL MOISTURE
WILL INCREASE RATHER QUICKLY WEST OF THE HUDSON TO CONTINUE WITH
THE SLIGHT CHANCE WORDING FOR SHOWERS. OTHERWISE...CLOUDS WILL BE
ON THE INCREASE WITH A RATHER TOUGH TEMPERATURE FORECAST AND MOS
VALUES THE PAST SEVERAL RUNS REMAINS RATHER STEADY. SO WE WILL
UTILIZE A BLENDED APPROACH WHICH LEANS MORE TOWARD THE MET MOS /IE
WARMER/.
THU-THU NIGHT...THE WARM FRONT LIFTS WELL NORTH OF THE REGION
WITH CONTINUED WEAK SYNOPTIC FORCING ASSOCIATED WITH THE DIFFERENTIAL
THERMAL ADVECTION. ISOLD-SCT SHOWERS AND/OR PERIODS OF DRIZZLE CAN
NOT BE RULED OUT WITH INCREASING HUMIDITY LEVELS. H850 TEMPS RISE
TO ~+10C BY LATE IN THE DAY. IT WILL BECOME BREEZY ONCE AGAIN DUE
TO THE INCREASING HORIZONTAL PRESSURE GRADIENT. WIDESPREAD 60S
WILL BE COMMON OVER THE FCST AREA WITH SOME MID AND U50S OVER THE
MTNS. THE SNOW MELT WILL LIKELY INCREASE DURING THIS TIME FRAME OVER
THE SRN DACKS...SRN GREENS...AND NRN BERKS. A MILD NIGHT IS
EXPECTED...AND LOW STRATUS MAY BECOME A PROBLEM IN THE WARM SECTOR
WITH DRIZZLE/ISOLD LIGHT SHOWERS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE PERIOD STARTS OUT ON FRIDAY WITH AN AMPLIFIED PATTERN
ALOFT...WITH A STRONG UPPER LEVEL LOW LIFTING NORTHEASTWARD ACROSS
THE GREAT LAKES REGION AND A STRONG RIDGE POSITIONED OVER THE
WESTERN ATLANTIC. OUR AREA WILL BE IN THE WARM SECTOR AHEAD OF A
COLD FRONT ATTACHED TO THE GREAT LAKES LOW...AND ON THE WESTERN
PERIPHERY OF THE WESTERN ATLANTIC RIDGE. THIS SHOULD RESULT IN A
MILD DAY WITH A GUSTY SOUTHERLY WIND. A FEW COMPLICATING FACTORS
WILL DETERMINE HOW WARM IT WILL GET AT THE SURFACE...INCLUDING THE
DEGREE OF MARINE INFLUENCE AND RESULTING POSSIBLE STRATUS CLOUDS
OVER THE AREA. IF PERIODS OF SUNSHINE CAN BREAK THROUGH...THEN TEMPS
MAY SOAR WELL INTO THE 70S. HOWEVER...IT IS UNCLEAR FOR NOW HOW MUCH
WARMING POTENTIAL WILL BE REALIZED. WILL FORECAST 60S TO LOWER 70S
AT THIS TIME...WHICH CLOSE TO MOST NUMERIC GUIDANCE.
THE AFOREMENTIONED COLD FRONT WILL PASS THROUGH THE REGION FROM WEST
TO EAST SATURDAY NIGHT. THE THREAT FOR SHOWERS WILL INCREASE BY
EVENING...BECOMING MORE PREVALENT BY MID TO LATE EVENING AND LASTING
INTO THE OVERNIGHT HOURS. DUE TO UNFAVORABLE TIME OF DAY AND
POSSIBLE MARINE INFLUENCES...NOT EXPECTING ANY SEVERE CONVECTION AT
THIS TIME BUT THERE IS ENOUGH EVIDENCE OF POSSIBLE ELEVATED
INSTABILITY TO MENTION A CHANCE OF THUNDER. SOUTHERLY WINDS WILL
BECOME QUITE GUSTY AHEAD OF THE COLD FRONT AS WELL. SHOWERS COULD
LINGER INTO SATURDAY MORNING DEPENDING ON THE SPEED OF THE FRONT.
OTHERWISE...COOL AND BREEZY CONDITIONS WITH SCATTERED SHOWERS WILL
ARE EXPECTED THROUGH THE AFTERNOON AS THE UPPER TROUGH AXIS PASSES
THROUGH.
DRYING AND SOME CLEARING SHOULD TAKE PLACE SATURDAY NIGHT...AS
STRONG HIGH PRESSURE OVER THE GREAT LAKES APPROACHES AND THE FLOW
ALOFT BECOMES MORE ZONAL. AFTER A CHILLY START...INCREASING SUNSHINE
AND LIGHTER WINDS LOOK TO BE IN STORE FOR SUNDAY...AS HIGH PRESSURE
CRESTS OVERHEAD. TEMPERATURES WILL STILL BE SLIGHTLY BELOW
NORMAL...BUT RELATIVELY LIGHT WINDS AND SUNSHINE WILL MAKE IT FEEL
PLEASANT. THE HIGH WILL DEPART INTO NEW ENGLAND ON MONDAY...BUT
RIDGING WILL EXTEND SOUTHWARD ALONG THE EASTERN SEABOARD AND SHOULD
KEEP OUR WEATHER DRY INTO TUESDAY. MODERATING TEMPERATURES ARE ALSO
EXPECTED WITH A RETURN SOUTHERLY FLOW DEVELOPING AROUND THE
DEPARTING HIGH.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONTAL PASSAGE BETWEEN 06-09Z AND ASSOCIATED PRECIPITATION
SHIELD WILL BRIEFLY LOWER CEILINGS/VISIBILITIES TO MVFR LEVELS
BEFORE 06Z...BEFORE A WEAK RIDGE OF HIGH PRESSURE RESTORES VFR
CONDITIONS TO ALL TAF SITES FOR THE REMAINDER OF THE TAF PERIOD.
THIS EVENING...LATEST RADAR IMAGERY CONTINUES TO SHOW A
REINVIGORATED BAND OF SHOWERS IMMEDIATELY AHEAD OF AND ALONG A COLD
FRONTAL BOUNDARY THAT IS NOW BEGINNING TO ENTER WESTERN NEW YORK.
THESE SHOWERS WILL CONTINUE TO MAINTAIN THEIR INTENSITY AS THEY
PROGRESS EASTWARD INTO THE FORECAST AREA...AND HAVE INDICATED TEMPO
GROUPS AT ALL TAF SITES FOR MVFR CEILINGS/VISIBILITIES THAT WILL
ACCOMPANY THE PASSAGE OF THE SHOWERS BETWEEN 00Z-06Z. HEAVIER
SHOWERS WILL BE ABLE TO MIX DOWN STRONGER GUSTS AS WELL. SOUTHERLY
WINDS WILL CONTINUE TO BE BREEZY BETWEEN 8-15 KNOTS THROUGH THE
EARLY EVENING HOURS...AS THE PRESSURE GRADIENT REMAINS TIGHT ACROSS
THE REGION.
TONIGHT INTO WEDNESDAY...WINDS WILL DIMINISH SLIGHTLY DURING THE
OVERNIGHT TO GENERALLY LESS THAN 10 KNOTS...AND VEER TO THE
NORTHWEST WITH THE FRONTAL PASSAGE.
SKIES SHOULD COMPLETELY CLEAR OUT BY WEDNESDAY MORNING AS THE WEAK
HIGH PRESSURE CRESTS OVER THE REGION. WINDS WEDNESDAY WILL BE
NORTHWESTERLY AND LIGHT GENERALLY LESS THAN 10 KNOTS.
OUTLOOK...
THU...MAINLY VFR. SLGT CHC -SHRA.
FRI-SAT...VFR-MVFR. BREEZY. CHC -SHRA.
SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
OCCASIONAL SHOWERS WILL MOVE ACROSS THE REGION THROUGH THIS
EVENING AS A COLD FRONT SLIDES ACROSS THE REGION. DRIER WEATHER IS
ON TAP FOR WEDNESDAY WITH WARMER AND MORE HUMID AIR RETURNS FOR
THE LATER HALF OF THE WEEK.
THE RH VALUES WILL INCREASE TO 70 TO 90 PERCENT TONIGHT...AND
THEN LOWER TO 25 TO 35 PERCENT ON WEDNESDAY.
THE WINDS WILL STRENGTHEN FROM THE SOUTH TO SOUTHWEST AT 15 TO 25
MPH WITH SOME GUSTS IN THE 30 TO 45 MPH RANGE THIS AFTERNOON. THE
WINDS WILL SHIFT TO THE WEST TO NORTHWEST TONIGHT AT 5 TO 15 MPH.
EXPECT NORTH TO NORTHWEST WINDS OF 5 TO 10 MPH ON WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED DURING THE WORK WEEK...WITH
SNOW MELT BEING MONITORED OVER THE NORTHERN BASINS IN THE SOUTHERN
ADIRONDACKS...AND SOUTHERN GREEN MOUNTAINS.
RAINFALL AMOUNTS TODAY HAVE REMAINED LESS THAN ONE QUARTER OF AN
INCH BASIN AVERAGE AND DRIER CONDITIONS ARE EXPECTED LATER TONIGHT
IN THE WAKE OF THE FRONTAL PASSAGE.
WITH MILDER TEMPERATURES EXPECTED MUCH OF THE WEEK...WHICH WILL
RESULT IN ADDITIONAL SNOWMELT IN THE SOUTHERN
ADIRONDACKS...SOUTHERN GREENS...AND THE NORTHERN BERKSHIRES. SOME
ISOLATED 5-10 INCH LIQUID EQUIVALENT AMOUNTS ARE IN THE SRN DACKS
AND SRN GREENS BASED ON THE LATEST NOHRSC GRAPHICS. SOME WITHIN
BANK RISES ARE EXPECTED WITH THE SNOWMELT AT SOME SITES.
THE LATEST MMEFS GEFS AND NAEFS INDICATE A 30 PERCENT CHANCE OF
RIVERBANK APPROACHING MINOR FLOOD STAGE TOWARDS THE WEEKEND. THIS
PROBABILITY IS LIKELY DUE TO SNOW MELT COMBINED WITH QPF WITH THE
LATE WEEK FRONT. ALSO...CLIMATOLOGICALLY RIVERBANK HAS MINOR
FLOODING DUE TO SNOW MELT. THIS SITE WILL BE MONITORED CAREFULLY
OVER THE NEXT FEW DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.CLIMATE...
FOR ALBANY WE ARE FORECASTING HIGHS IN THE 60S THIS WEEK WITH 70S
ON FRIDAY. THE LAST TIME TEMPERATURES WERE THIS WARM WAS BACK IN
NOVEMBER ON THE 12TH WITH A HIGH OF 67 DEGREES AND THE 13TH WITH A
HIGH OF 63 DEGREES. THE LAST TIME IT WAS 70+ DEGREES IN ALBANY WAS
BACK IN OCTOBER ON THE 20TH WITH A HIGH OF 70 DEGREES AND THE 5TH
WITH A HIGH OF 74 DEGREES.
THIS SPRING IN ALBANY WE HAVE ONLY HAD THREE HIGH TEMPERATURES IN
THE 60S: APRIL 7TH (60 DEGREES)...APRIL 8TH (61 DEGREES) AND APRIL
9TH (60 DEGREES).
NORMAL TEMPERATURES FOR MID APRIL ARE:
ALBANY: HIGHS AROUND 60. LOWS UPPER 30S.
GLENS FALLS: HIGHS UPPER 50S. LOWS LOWER 30S.
POUGHKEEPSIE: HIGHS LOWER 60S. LOWS UPPER 30S.
BENNINGTON: HIGHS UPPER 50S. LOWS MID 30S.
PITTSFIELD: HIGHS MID 50S. LOWS MID 30S.
&&
.EQUIPMENT...
OUR UPPER AIR EQUIPMENT WILL REMAIN OUT OF SERVICE UNTIL FURTHER
NOTICE...A PART IS ON ORDER.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...IRL/BGM/SNYDER
SHORT TERM...BGM
LONG TERM...JPV
AVIATION...IRL/SNYDER
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS ALBANY NY
741 PM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL SLIDE SOUTH OF THE REGION THIS
EVENING. HIGH PRESSURE WILL BRIEFLY BUILD IN FROM THE NORTH WITH
FAIR AND DRY WEATHER FOR WEDNESDAY. THE COLD FRONT WILL LIFT BACK
NORTHWARD AS A WARM FRONT WEDNESDAY NIGHT INTO THURSDAY WITH
ISOLATED TO SCATTERED SHOWERS AND A RETURN TO MILDER WEATHER.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 730 PM EDT...REINVIGORATED BAND OF SHOWERS HAS FORMED AHEAD OF
AND IMMEDIATELY ALONG A COLD FRONT NOW BEGINNING TO MOVE THROUGH
WESTERN NEW YORK. MUCH OF THE MODEL GUIDANCE HAS CONTINUED TO SHOW A
MORE PROGRESSIVE FRONTAL PASSAGE...HOWEVER THE HRRR SEEMS TO BE THE
CLOSEST IN AGREEMENT WITH CURRENT OBSERVATIONS....WHICH WOULD DEPICT
THE COLD FRONT CROSSING THE FORECAST AREA IN THE 06-09Z TIMEFRAME.
HAVE MADE ADJUSTMENTS TO POPS IN GRIDS TO ACCOUNT FOR THIS TIMING.
A LINE OF HEAVIER SHOWERS HAS DEVELOPED ALONG A WEAK INSTABILITY
AXIS ACROSS PORTIONS OF SOUTHWESTERN NEW YORK. GIVEN WEAK
ELEVATED INSTABILITY ACROSS THE AREA AND LATEST VAD PROFILES
DEPICTING 30-40 KNOTS JUST ABOVE THE SURFACE...ANY SHOWERS THAT
DEVELOP CONVECTIVE ELEMENTS WILL BE ABLE TO MIX DOWN SOME STRONGER
WIND GUSTS. WILL HAVE TO MONITOR THIS ACTIVITY AS IT PROGRESSES
THROUGH THE FORECAST AREA AND ADDRESS WITH SPECIAL WEATHER
STATEMENTS AS NEEDED.
BEHIND THE COLD FRONT...HIGH PRESSURE OVER NORTHERN-CENTRAL
CANADA WILL BEGIN TO EXTEND ITS INFLUENCES ACROSS THE GREAT LAKES
REGION AND INTO NEW ENGLAND LATE TONIGHT. THIS WILL ALLOW FOR
PARTIAL CLEARING SKIES FROM NORTH TO SOUTH. BASED ON UPSTREAM
TEMPERATURES...WILL FAVOR A BLEND OF MOS GUIDANCE WITH PERHAPS ON
THE COOLER SIDE NORTH OF I90 WHERE SKIES MAY CLEAR FOR A PERIOD OF
TIME BEFORE SUNRISE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
WEDNESDAY...THE FRONTAL BOUNDARY BECOMES QUASI-STATIONARY OVER
THE I80 CORRIDOR WITH THAT LARGE SURFACE HIGH EXTENDING ITS
INFLUENCES OVER THE NORTHEAST CORRIDOR OF THE CONUS. MOSTLY
SUNNY AND DRY CONDITIONS ARE EXPECTED WITH DECENT MIXING /A FEW
MORE CLOUDS ARE EXPECTED SOUTH OF I90/ AS TEMPERATURES SHOULD AVERAGE
AROUND 60F TO MID 60S IN THE VALLEYS...AND 50S MAINLY OVER THE MTNS
/A FEW U40S OVER THE DACKS AND SOUTHERN GREENS/.
WEDNESDAY NIGHT...AS THE SURFACE HIGH SLIDES NORTHEAST OF THE
REGION...A POTENT STORM TAKES SHAPE ACROSS THE CENTER OF THE
NATION. THIS WILL SET UP AN INCREASING SOUTHERLY FLOW OF WARMER
AND MORE MOIST AIR INTO THE REGION WITH THE PASSAGE OF A WARM
FRONT. THERE ARE INCREASING HINTS THAT THE LOWER LEVEL MOISTURE
WILL INCREASE RATHER QUICKLY WEST OF THE HUDSON TO CONTINUE WITH
THE SLIGHT CHANCE WORDING FOR SHOWERS. OTHERWISE...CLOUDS WILL BE
ON THE INCREASE WITH A RATHER TOUGH TEMPERATURE FORECAST AND MOS
VALUES THE PAST SEVERAL RUNS REMAINS RATHER STEADY. SO WE WILL
UTILIZE A BLENDED APPROACH WHICH LEANS MORE TOWARD THE MET MOS /IE
WARMER/.
THU-THU NIGHT...THE WARM FRONT LIFTS WELL NORTH OF THE REGION
WITH CONTINUED WEAK SYNOPTIC FORCING ASSOCIATED WITH THE DIFFERENTIAL
THERMAL ADVECTION. ISOLD-SCT SHOWERS AND/OR PERIODS OF DRIZZLE CAN
NOT BE RULED OUT WITH INCREASING HUMIDITY LEVELS. H850 TEMPS RISE
TO ~+10C BY LATE IN THE DAY. IT WILL BECOME BREEZY ONCE AGAIN DUE
TO THE INCREASING HORIZONTAL PRESSURE GRADIENT. WIDESPREAD 60S
WILL BE COMMON OVER THE FCST AREA WITH SOME MID AND U50S OVER THE
MTNS. THE SNOW MELT WILL LIKELY INCREASE DURING THIS TIME FRAME OVER
THE SRN DACKS...SRN GREENS...AND NRN BERKS. A MILD NIGHT IS
EXPECTED...AND LOW STRATUS MAY BECOME A PROBLEM IN THE WARM SECTOR
WITH DRIZZLE/ISOLD LIGHT SHOWERS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE PERIOD STARTS OUT ON FRIDAY WITH AN AMPLIFIED PATTERN
ALOFT...WITH A STRONG UPPER LEVEL LOW LIFTING NORTHEASTWARD ACROSS
THE GREAT LAKES REGION AND A STRONG RIDGE POSITIONED OVER THE
WESTERN ATLANTIC. OUR AREA WILL BE IN THE WARM SECTOR AHEAD OF A
COLD FRONT ATTACHED TO THE GREAT LAKES LOW...AND ON THE WESTERN
PERIPHERY OF THE WESTERN ATLANTIC RIDGE. THIS SHOULD RESULT IN A
MILD DAY WITH A GUSTY SOUTHERLY WIND. A FEW COMPLICATING FACTORS
WILL DETERMINE HOW WARM IT WILL GET AT THE SURFACE...INCLUDING THE
DEGREE OF MARINE INFLUENCE AND RESULTING POSSIBLE STRATUS CLOUDS
OVER THE AREA. IF PERIODS OF SUNSHINE CAN BREAK THROUGH...THEN TEMPS
MAY SOAR WELL INTO THE 70S. HOWEVER...IT IS UNCLEAR FOR NOW HOW MUCH
WARMING POTENTIAL WILL BE REALIZED. WILL FORECAST 60S TO LOWER 70S
AT THIS TIME...WHICH CLOSE TO MOST NUMERIC GUIDANCE.
THE AFOREMENTIONED COLD FRONT WILL PASS THROUGH THE REGION FROM WEST
TO EAST SATURDAY NIGHT. THE THREAT FOR SHOWERS WILL INCREASE BY
EVENING...BECOMING MORE PREVALENT BY MID TO LATE EVENING AND LASTING
INTO THE OVERNIGHT HOURS. DUE TO UNFAVORABLE TIME OF DAY AND
POSSIBLE MARINE INFLUENCES...NOT EXPECTING ANY SEVERE CONVECTION AT
THIS TIME BUT THERE IS ENOUGH EVIDENCE OF POSSIBLE ELEVATED
INSTABILITY TO MENTION A CHANCE OF THUNDER. SOUTHERLY WINDS WILL
BECOME QUITE GUSTY AHEAD OF THE COLD FRONT AS WELL. SHOWERS COULD
LINGER INTO SATURDAY MORNING DEPENDING ON THE SPEED OF THE FRONT.
OTHERWISE...COOL AND BREEZY CONDITIONS WITH SCATTERED SHOWERS WILL
ARE EXPECTED THROUGH THE AFTERNOON AS THE UPPER TROUGH AXIS PASSES
THROUGH.
DRYING AND SOME CLEARING SHOULD TAKE PLACE SATURDAY NIGHT...AS
STRONG HIGH PRESSURE OVER THE GREAT LAKES APPROACHES AND THE FLOW
ALOFT BECOMES MORE ZONAL. AFTER A CHILLY START...INCREASING SUNSHINE
AND LIGHTER WINDS LOOK TO BE IN STORE FOR SUNDAY...AS HIGH PRESSURE
CRESTS OVERHEAD. TEMPERATURES WILL STILL BE SLIGHTLY BELOW
NORMAL...BUT RELATIVELY LIGHT WINDS AND SUNSHINE WILL MAKE IT FEEL
PLEASANT. THE HIGH WILL DEPART INTO NEW ENGLAND ON MONDAY...BUT
RIDGING WILL EXTEND SOUTHWARD ALONG THE EASTERN SEABOARD AND SHOULD
KEEP OUR WEATHER DRY INTO TUESDAY. MODERATING TEMPERATURES ARE ALSO
EXPECTED WITH A RETURN SOUTHERLY FLOW DEVELOPING AROUND THE
DEPARTING HIGH.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONTAL PASSAGE BETWEEN 06-09Z AND ASSOCIATED PRECIPITATION
SHIELD WILL BRIEFLY LOWER CEILINGS/VISIBILITIES TO MVFR LEVELS
BEFORE 06Z...BEFORE A WEAK RIDGE OF HIGH PRESSURE RESTORES VFR
CONDITIONS TO ALL TAF SITES FOR THE REMAINDER OF THE TAF PERIOD.
THIS EVENING...LATEST RADAR IMAGERY CONTINUES TO SHOW A
REINVIGORATED BAND OF SHOWERS IMMEDIATELY AHEAD OF AND ALONG A COLD
FRONTAL BOUNDARY THAT IS NOW BEGINNING TO ENTER WESTERN NEW YORK.
THESE SHOWERS WILL CONTINUE TO MAINTAIN THEIR INTENSITY AS THEY
PROGRESS EASTWARD INTO THE FORECAST AREA...AND HAVE INDICATED TEMPO
GROUPS AT ALL TAF SITES FOR MVFR CEILINGS/VISIBILITIES THAT WILL
ACCOMPANY THE PASSAGE OF THE SHOWERS BETWEEN 00Z-06Z. HEAVIER
SHOWERS WILL BE ABLE TO MIX DOWN STRONGER GUSTS AS WELL. SOUTHERLY
WINDS WILL CONTINUE TO BE BREEZY BETWEEN 8-15 KNOTS THROUGH THE
EARLY EVENING HOURS...AS THE PRESSURE GRADIENT REMAINS TIGHT ACROSS
THE REGION.
TONIGHT INTO WEDNESDAY...WINDS WILL DIMINISH SLIGHTLY DURING THE
OVERNIGHT TO GENERALLY LESS THAN 10 KNOTS...AND VEER TO THE
NORTHWEST WITH THE FRONTAL PASSAGE.
SKIES SHOULD COMPLETELY CLEAR OUT BY WEDNESDAY MORNING AS THE WEAK
HIGH PRESSURE CRESTS OVER THE REGION. WINDS WEDNESDAY WILL BE
NORTHWESTERLY AND LIGHT GENERALLY LESS THAN 10 KNOTS.
OUTLOOK...
THU...MAINLY VFR. SLGT CHC -SHRA.
FRI-SAT...VFR-MVFR. BREEZY. CHC -SHRA.
SUN...VFR. NO SIG WX.
&&
.FIRE WEATHER...
OCCASIONAL SHOWERS WILL MOVE ACROSS THE REGION THROUGH THIS
EVENING AS A COLD FRONT SLIDES ACROSS THE REGION. DRIER WEATHER IS
ON TAP FOR WEDNESDAY WITH WARMER AND MORE HUMID AIR RETURNS FOR
THE LATER HALF OF THE WEEK.
THE RH VALUES WILL INCREASE TO 70 TO 90 PERCENT TONIGHT...AND
THEN LOWER TO 25 TO 35 PERCENT ON WEDNESDAY.
THE WINDS WILL STRENGTHEN FROM THE SOUTH TO SOUTHWEST AT 15 TO 25
MPH WITH SOME GUSTS IN THE 30 TO 45 MPH RANGE THIS AFTERNOON. THE
WINDS WILL SHIFT TO THE WEST TO NORTHWEST TONIGHT AT 5 TO 15 MPH.
EXPECT NORTH TO NORTHWEST WINDS OF 5 TO 10 MPH ON WEDNESDAY.
&&
.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE EXPECTED DURING THE WORK WEEK...WITH
SNOW MELT BEING MONITORED OVER THE NORTHERN BASINS IN THE SOUTHERN
ADIRONDACKS...AND SOUTHERN GREEN MOUNTAINS.
RAINFALL AMOUNTS TODAY HAVE REMAINED LESS THAN ONE QUARTER OF AN
INCH BASIN AVERAGE AND DRIER CONDITIONS ARE EXPECTED LATER TONIGHT
IN THE WAKE OF THE FRONTAL PASSAGE.
WITH MILDER TEMPERATURES EXPECTED MUCH OF THE WEEK...WHICH WILL
RESULT IN ADDITIONAL SNOWMELT IN THE SOUTHERN
ADIRONDACKS...SOUTHERN GREENS...AND THE NORTHERN BERKSHIRES. SOME
ISOLATED 5-10 INCH LIQUID EQUIVALENT AMOUNTS ARE IN THE SRN DACKS
AND SRN GREENS BASED ON THE LATEST NOHRSC GRAPHICS. SOME WITHIN
BANK RISES ARE EXPECTED WITH THE SNOWMELT AT SOME SITES.
THE LATEST MMEFS GEFS AND NAEFS INDICATE A 30 PERCENT CHANCE OF
RIVERBANK APPROACHING MINOR FLOOD STAGE TOWARDS THE WEEKEND. THIS
PROBABILITY IS LIKELY DUE TO SNOW MELT COMBINED WITH QPF WITH THE
LATE WEEK FRONT. ALSO...CLIMATOLOGICALLY RIVERBANK HAS MINOR
FLOODING DUE TO SNOW MELT. THIS SITE WILL BE MONITORED CAREFULLY
OVER THE NEXT FEW DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.CLIMATE...
FOR ALBANY WE ARE FORECASTING HIGHS IN THE 60S THIS WEEK WITH 70S
ON FRIDAY. THE LAST TIME TEMPERATURES WERE THIS WARM WAS BACK IN
NOVEMBER ON THE 12TH WITH A HIGH OF 67 DEGREES AND THE 13TH WITH A
HIGH OF 63 DEGREES. THE LAST TIME IT WAS 70+ DEGREES IN ALBANY WAS
BACK IN OCTOBER ON THE 20TH WITH A HIGH OF 70 DEGREES AND THE 5TH
WITH A HIGH OF 74 DEGREES.
THIS SPRING IN ALBANY WE HAVE ONLY HAD THREE HIGH TEMPERATURES IN
THE 60S: APRIL 7TH (60 DEGREES)...APRIL 8TH (61 DEGREES) AND APRIL
9TH (60 DEGREES).
NORMAL TEMPERATURES FOR MID APRIL ARE:
ALBANY: HIGHS AROUND 60. LOWS UPPER 30S.
GLENS FALLS: HIGHS UPPER 50S. LOWS LOWER 30S.
POUGHKEEPSIE: HIGHS LOWER 60S. LOWS UPPER 30S.
BENNINGTON: HIGHS UPPER 50S. LOWS MID 30S.
PITTSFIELD: HIGHS MID 50S. LOWS MID 30S.
&&
.EQUIPMENT...
OUR UPPER AIR EQUIPMENT WILL REMAIN OUT OF SERVICE UNTIL FURTHER
NOTICE...A PART IS ON ORDER.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...IRL/BGM/SNYDER
SHORT TERM...BGM
LONG TERM...JPV
AVIATION...IRL/SNYDER
FIRE WEATHER...BGM/WASULA
HYDROLOGY...BGM/WASULA
CLIMATE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TOPEKA KS
932 PM CDT TUE APR 16 2013
.UPDATE...
ISSUED AT 912 PM CDT TUE APR 16 2013
00Z SND FROM TOP AND DOWNSTREAM AT DDC AND AMA SHOW A FAIRLY STOUT
CAP ON THE BOTTOM OF THE EML. PARCELS ABOVE THE SHALLOW COLD
AIR-MASS MAY NOT REACH THEIR LFC`S UNTIL LATE TONIGHT WHEN DEEPER
MOISTURE ADVECTION AND A STRENGTHENING LLJ MAY CAUSE PARCELS TO
REACH THEIR LFC. THE HRRR AND RAP MODELS SEEM TO BE THE BEST JOB
WITH INITIALIZATION AND MAY HAVE THE BEST PERFORMANCE WITH
ELEVATED CONVECTION. BOTH MODELS SHOW ELEVATED CONVECTION
DEVELOPING ACROSS CENTRAL AND NORTH CENTRAL KS BY 9Z...WITH THE
ELEVATED THUNDERSTORMS MOVING NORTHEAST ACROSS THE NORTHWEST
COUNTIES OF THE CWA THROUGH THE EARLY MORNING HOURS. ELEVATED
CONVECTION MAY FORM LATE TONIGHT ACROSS SOUTH CENTRAL AND CENTRAL KS AND
INTENSIFY AS IT MOVES NORTHEAST INTO THE REMAINDER OF THE CWA. THE
RAP INCREASES MUCAPE TO 1500 TO 2000 J/KG ACROSS THE WESTERN
COUNTIES OF THE CWA AFTER 12Z. WHILE SFC TO 6KM BULK SHEAR WILL BE
50 TO 60 KTS...THUS SOME OF THE ELEVATED THUNDERSTORMS MAY DEVELOP
MID-LEVEL MESO`S AND PRODUCE LARGE HAIL. THE BIG QUESTION
CONTINUES TO BE CAP STRENGTH...AND WHEN AND WHERE THE ELEVATED
THUNDERSTORMS WILL DEVELOP. MY THINKING IS BETWEEN 7Z-8Z ACROSS
NORTH CENTRAL KS WITH FARTHER DEVELOPMENT ACROSS THE REMAINDER OF
THE CWA TOWARDS 12Z.
SCATTERED SHOWERS MAY DEVELOP BEFORE ANY ELEVATED
CONVECTION DOES...THUS I KEPT SOME POPS THROUGH THE LATE EVENING AND
EARLY MORNING HOURS ACROSS THE CWA.
GARGAN
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE APR 16 2013
SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE CENTRAL PLAINS AS A UPPER
TROUGH DIGS SOUTH ACROSS THE WESTERN U.S. THIS AFTERNOON AT 19Z.
SURFACE FRONTAL BOUNDARY WAS LOCATED FROM NORTHERN TEXAS NORTHEAST
INTO ARKANSAS AND SOUTHEAST MISSOURI. FURTHER NORTH OF THE WARM
FRONT CENTRAL AND EASTERN KANSAS REMAIN IN THE COOL SECTOR WITH
TEMPERATURES IN THE 40S.
FOR TONIGHT...ISENTROPIC LIFT INCREASES THIS EVENING AS PARCELS ARE
LIFTED OVER THE COLD DOME NORTH OF THE WARM FRONT. MOISTURE
TRANSPORT VECTORS INCREASE THIS EVENING AS THE LOW LEVEL JET
INCREASES. LAPSE RATES IN THE MID LEVELS WILL STEEPEN AND ELEVATED
INSTABILITY WILL INCREASE AS WELL ACROSS CENTRAL AND EASTERN KANSAS.
GIVEN FAVORABLE SHEAR...MOISTURE AND INSTABILITY TONIGHT SOME STORMS
MAY BECOME SEVERE AND PRODUCE LARGE HAIL OVERNIGHT.
WEDNESDAY...DIFFERENCES EXIST BETWEEN THE GFS AND THE NAM...ECMWF AS
WELL AS THE UKMET. THE GFS IS FURTHER NORTH WITH THE WARM SECTOR
WHILE THE OTHERS KEEP IT ACROSS EAST CENTRAL KANSAS IN THE
AFTERNOON. AGAIN FAVORABLE SHEAR...INCREASING INSTABILITY AND
MOISTURE WILL COME TOGETHER FOR STRONG TO SEVERE STORMS. THE MORNING
CONVECTION COULD STILL BE PRODUCING HAIL. BY AFTERNOON...AS PARCELS
RISE UP OVER THE FRONT INTO INCREASINGLY UNSTABLE AIR
HOWEVER...SEVERE HAIL WILL REMAIN THE PRIMARY THREAT FOR THE EASTERN
2/3 OF THE FORECAST AREA...WITH RISK OF SURFACE BASED
STORMS/TORNADIC THREAT GENERALLY ALONG AND SE OF THE INTERSTATE 35
CORRIDOR. IF THE WARM AIR IS FURTHER NORTH THEN THE CONVECTION WILL
INCREASE FURTHER NORTH AS WELL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE APR 16 2013
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...
FRONT WILL CONTINUE TO PUSH SOUTH AND EAST OF I 35 THROUGH THE
EVENING. AS THE UPPER LEVEL TROUGH IN THE ROCKIES ADVANCES EASTWARD
INTO THE AREA STRONG FORCING AHEAD OF THE FRONT AND POST FRONTAL
WILL CONTINUE ACROSS THE NORTHEAST AND EAST CENTRAL AREAS...BUT
INSTABILITY WILL SLOWLY DECREASE THROUGH MIDNIGHT WITH AN ADDITIONAL
HALF OF ONE INCH OF RAIN...WITH LIGHTER AMOUNTS OF A QUARTER TO HALF
INCH IN THE NORTH CENTRAL. AS THE COLDER AND DRIER AIR ADVANCES EAST
WARD BEHIND THE FRONT...HIGH POPS ARE STILL WARRANTED...BUT PRECIP
AMOUNTS WILL BE ON THE DECLINE. AS THE COLDER AIR POURS INTO THE CWA
WEDNESDAY NIGHT INTO THURSDAY MORNING ON THE HEELS OF BLUSTERY NORTH
NORTHWEST WINDS...THERE IS A CHANCE FOR THE RAIN TO MIX WITH
SLEET...THEN SNOW IN THE FAR NORTH CENTRAL. UP TO AN INCH OF SNOW IS
POSSIBLE IN THE FAR NORTHWEST CORNER OF THE CWA BEFORE PRECIP
DECREASES TOWARDS MIDDAY. THE RAIN/SNOW MIX COULD MAKE IT AS FAR
EAST AS THE TURNPIKE ON THURSDAY AND LINGER OVER THE NORTHERN AND
EAST CWA THURSDAY EVENING ON THE BACKSIDE OF THE EXITING TROUGH.
AFTER LOWS WEDNESDAY NIGHT IN THE 40S EAST AND THE LOW TO MID 30S
WEST...HIGHS ON THURSDAY WILL ONLY RISE A FEW DEGREES FROM THE
MORNING LOWS.
A COLDER NIGHT IS IN STORE FOR THE AREA THURSDAY NIGHT WITH FREEZING
TEMPS EXPECTED IN MANY AREAS AS LOWS FALL INTO THE MIDDLE 20S NORTH
CENTRAL TO THE LOWER 30S NORTHEAST AND EAST CENTRAL. UNDER MOSTLY
SUNNY SKIES ON FRIDAY HIGH TEMPS WILL RECOVER BACK INTO THE UPPER
40S TO LOWER 50S.
FRIDAY THROUGH TUESDAY...
FRIDAY NIGHT THE LONG WAVE TROUGH WILL CONTINUE TO ADVANCE EASTWARD
AS SURFACE HIGH PRESSURE SETTLES OVERHEAD. WITH LIGHT WINDS AND A
COLD AIR MASS IN PLACE IT WILL BE QUIET CHILLY SATURDAY MORNING
AS LOW TEMPERATURES DROP INTO LOW 30S WHICH IS WELL BELOW NORMAL
THIS TIME OF YEAR. THIS MEANS THERE IS THE POTENTIAL FOR FROST
ACROSS PARTS OF THE REGION. ON SUNDAY A SHORTWAVE WILL DIVE
SOUTHEAST INTO THE NORTHERN AND CENTRAL PLAINS. AHEAD OF THE
APPROACHING SHORTWAVE LOW LEVEL SOUTHERLY FLOW WILL ALLOW MOISTURE
TO RETURN TO THE AREA. THIS BRINGS A CHANCE OF SHOWERS AND
THUNDERSTORMS ON SUNDAY AND MONDAY. THE MAIN TROUGH WILL PROGRESS
INTO THE NORTHERN US AND A TRAILING COLD FRONT WILL EXTEND SOUTH
ACROSS THE REGION. BEHIND THE COLD FRONT ANOTHER SHOT OF
UNSEASONAL COLD AIR WILL FILTER SOUTH ACROSS THE AREA. THE ECMWF
IS SUGGESTING POST FRONTAL PRECIPITATION WHICH WOULD MEAN A MIX OF
RAIN AND SNOW MONDAY NIGHT AND TUESDAY MORNING. DUE TO LOW
UNCERTAINTY DID NOT ADD SNOW INTO THE FORECAST ATTM. THIS SHOT OF
COLD AIR COULD ALSO BRING ANOTHER CHANCE OF FROST MONDAY
NIGHT...BUT WILL HAVE TO MONITOR ADDITIONAL MODEL OUTPUT BEFORE
ADDRESSING THE DETAILS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 637 PM CDT TUE APR 16 2013
VFR STRATUS AT THE TAF SITES WILL GRADUALLY LOWER TO MVFR CEILINGS
THROUGH THE EVENING...THEN IFR CEILINGS AFTER 6Z WED. SHOWERS AND
ELEVATED THUNDERSTORMS WILL DEVELOP LATE TONIGHT ACROSS THE TAF
SITES AND EXTEND THROUGH THE MID MORNING HOURS. IF WINDS BECOME
SOUTHERLY AHEAD OF A SURFACE COLD FRONT THERE MAY BE ENOUGH MIXING
TUESDAY AFTERNOON TO ALLOW CEILINGS TO INCREASE TO MVFR CRITERIA.
THERE WILL ALSO BE A GOOD CHANCE FOR AFTERNOON AND EVENING
THUNDERSTORMS AT THE TAF SITES ON TUESDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...53
LONG TERM...SANDERS/63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
314 AM EDT MON APR 15 2013
.UPDATE...
ISSUED AT 105 AM EDT MON APR 15 2013
UPDATED THE FORECAST TO BETTER REFLECT THE ON-GOING MEASURABLE RAIN
OVER THE NORTHEAST PORTION OF THE CWA. THIS RAIN HAS ALSO KNOCKED
DOWN TEMPERATURES...WAY OFF OF OUR FORECAST DIURNAL TRACK SO THAT
THEY ARE NEAR THE LOWS IN THE SOUTH WHILE STILL DECENT IN THE NORTH.
HAVE ADDRESSED THIS AS WELL WITH THIS UPDATE. LIKEWISE...DECIDED TO
LOAD IN THE LATEST TD GRIDS FROM THE HRRR AS THE OTHER GUIDANCE IS
PRETTY FAR OFF...ASIDE FROM THE GMOS. THE LIGHT RAIN WILL PIVOT OUT
OF THE AREA BY DAWN...LINGERING THE LONGEST OVER OUR FAR EASTERN
TERRITORY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. A
FRESH SET OF ZONES WILL FOLLOW SHORTLY.
UPDATE ISSUED AT 1143 PM EDT SUN APR 14 2013
HAD TO MAKE ANOTHER QUICK UPDATE TO THE FORECAST. SURFACE
OBSERVATIONS FROM LOCATIONS SOUTH AND SOUTHEAST OF THE WEATHER OFFICE
HAVE PICKED UP ENOUGH RAIN OVER THE PAST FEW HOURS TO WARRANT HIGHER
THAN SLIGHT CHANCE POPS. A NUMBER OF RAWS...AWOS...AND OTHER
OBSERVATIONS SITES FROM WAYNE COUNTY EASTWARD TO LETCHER COUNTY HAVE
MEASURED AT LEAST A FEW HUNDREDTHS OF AN INCH OF RAIN SINCE 8 PM.
THEREFORE...DECIDED TO INCREASE PRECIPITATION CHANCES FOR THE 2 TO 6Z
TIME FRAME TONIGHT TO BETTER REFLECT ACTUAL TRENDS IN THE WEATHER.
THE APPROPRIATE CHANGES WERE MADE TO THE QPF AND WEATHER GRIDS AS
WELL BASED ON THE NEW POP FORECAST. THE REST OF THE FORECAST WAS IN
GOOD SHAPE AS IS.
UPDATE ISSUED AT 927 PM EDT SUN APR 14 2013
WITH MEASURABLE PRECIPITATION ALREADY OCCURRING BETWEEN THE TENNESSEE
BORDER AND THE HAL ROGERS PARKWAY HIGHWAY 80 CORRIDOR...WAS NECESSARY
TO UPDATE THE FORECAST TO REFLECT THE CURRENT TRENDS AND CONDITIONS.
IN A NUTSHELL...MEASURABLE PRECIPITATION IS OCCURRING EARLIER AND A
BIT FURTHER NORTH THEN THE INHERITED FORECAST WAS INDICATING...SO THE
APPROPRIATE CHANGES HAVE BEEN MADE TO BOTH THE GRIDS AND THE ZONE
FORECAST TEXT PRODUCT. THE TEMPERATURES...WIND...AND SKY COVER
FORECAST ELEMENTS ARE ALL ON TRACK FOR THE NIGHT...SO NO CHANGES WERE
MADE TO ANY OF THOSE. THE UPDATED FORECAST HAS ALREADY BEEN ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 331 PM EDT SUN APR 14 2013
HIGH CLOUDS CONTINUE TO STREAM IN FROM THE SOUTHWEST OUT AHEAD OF A
SHORT WAVE TROUGH SWINGING THROUGH THE GULF COAST STATES. THE MODELS
ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...SWINGING THIS WAVE
NORTHEAST ACROSS THE SOUTHERN APPALACHIANS TONIGHT...BEFORE EXITING
ACROSS THE MID-ATLANTIC ON MONDAY...WITH WEAK RIDGING TO FOLLOW
ACROSS THE EASTERN SEABOARD.
THE MODELS HAVE TRENDED A BIT MORE AGGRESSIVE WITH THE POPS ACROSS
SOUTHEASTERN KENTUCKY TONIGHT. GIVEN THE AGREEMENT...INCREASED POPS
SOMEWHAT...ALTHOUGH WITH THE CURRENT LOW LEVEL DRY AIR IN PLACE...AM
NOT TOO CONFIDENT THIS FAIRLY FAST MOVING SYSTEM WILL BE ABLE TO
SATURATE THE LOW LEVELS IN TIME FOR MEASURABLE PRECIPITATION.
THE THICKER CLOUDS WILL MITIGATE THE RIDGE/VALLEY SPLIT TONIGHT...WITH
MOST LOCATIONS BOTTOMING OUT IN THE LOW TO MID 50S. CLOUDS WILL BE ON
THE DECREASE BY MONDAY AFTERNOON AS SOME SHORT WAVE RIDGING FOLLOWS
IN THE WAKE OF THE EXITING SHORT WAVE TROUGH. HIGHS WILL REBOUND TO
THE MID AND UPPER 70S.
FOR MONDAY NIGHT...A WEAKENING COLD FRONT WILL ATTEMPT TO APPROACH
FROM THE NORTHWEST...BUT LOOKS TO STAY NORTH OF THE OHIO RIVER. WILL
CONTINUE WITH JUST A SLIGHT CHANCE OF A SHOWER OR STORM THREATENING
THE BLUEGRASS LATE. CLOUDS WILL BE LESS EXTENSIVE MONDAY NIGHT...AND
WITH LIGHT SOUTHERLY WINDS...THIS SHOULD SET UP MORE A RIDGE/VALLEY
SPLIT. COOLER VALLEYS WILL BOTTOM OUT IN THE LOWER 50S...WHILE RIDGES
STAY UP AT AROUND 60.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 314 AM EDT MON APR 15 2013
FORECAST CONCERNS FOR THE PERIOD CONTINUE TO REVOLVE AROUND
THUNDERSTORM CHANCES MIDWEEK AND THEN TIMING OF A FRONTAL PASSAGE
THROUGH OUR REGION LATE IN THE WORK WEEK.
MODELS CONTINUE TO BUILD AN UPPER LEVEL RIDGE INTO THE SOUTHERN
APPALACHIANS ON TUESDAY NIGHT AND WEDNESDAY. THEY ALSO INDICATE
PLENTY OF SURFACE BASED INSTABILITY ALONG WITH WEAK DISTURBANCES
PASSING OVER OUR REGION AS THEY ROUND THE TOP OF THE RIDGE. THUS
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TUESDAY
NIGHT INTO THE DAY ON WEDNESDAY. GIVEN ANY SUNSHINE AT ALL WE SHOULD
BE ABLE TO CLIMB INTO THE LOW 80S FOR MOST LOCATIONS WEDNESDAY
AFTERNOON.
STRONG SOUTHERLY FLOW WILL THEN COMMENCE WEDNESDAY NIGHT INTO THE
DAY ON THURSDAY AS AN UPPER LEVEL TROUGH BEGINS TO TREK ACROSS THE
PLAINS INTO THE MIDWEST. THIS DOWNSLOPE FLOW SHOULD DECREASE OUR
INSTABILITY AND THUNDERSTORM CHANCES ON THURSDAY...AND HELP US WARM
INTO THE LOW TO MID 80S. SURFACE WINDS ARE EXPECTED TO GUST UP TO 30
MPH DURING THE AFTERNOON HOURS AS WELL.
THE COLD FRONT IS THEN PROGGED TO PASS THROUGH EAST KENTUCKY ON
FRIDAY MORNING. IT WILL BE STRUNG OUT BY THE TIME IT REACHES US WITH
VERY LITTLE IF ANY INSTABILITY SHOWING UP IN THE PROGS AND WILL ONLY
ADVERTISE A SLIGHT CHANCE OF THUNDER IN ADVANCE OF THE FRONT
THURSDAY NIGHT...AND WITH THE FRONT ON FRIDAY. STILL CANNOT RULE OUT
THIS THING SLOWING DOWN EVEN MORE EITHER SO WILL HOLD ONTO A SMALL
POP FRIDAY NIGHT. OTHERWISE...THE WEEKEND LOOKS DRY WITH
TEMPERATURES COOLING BACK DOWN INTO THE 50S TO LOW 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 115 AM EDT MON APR 15 2013
THE SFC WAVE PASSING BY TO THE SOUTHEAST WILL CLEAR OUT THE LIGHT
RAIN FROM THE TAF SITES DURING THE EARLY MORNING HOURS AND THE REST
OF THE AREA BY DAWN. EVEN AS THE WX IMPROVES...THE CIGS WILL PROBABLY
BRIEFLY FALL TO MVFR AROUND DAWN. THE WAVE WILL EVENTUALLY GET FAR
ENOUGH EAST TO ALLOW CIGS TO CLIMB OR CLEAR OUT ENTIRELY RESUMING THE
VFR CONDITIONS BY MID MORNING MONDAY. THIS SHOULD BE THE CASE THROUGH
EVENING...THOUGH CIGS WILL LIKELY RETURN AND LOWER TOWARDS MIDNIGHT
AHEAD OF A SAGGING FRONT FROM THE NORTHWEST. WINDS WILL BE GENERALLY
LIGHT FROM THE SOUTH THROUGH THE PERIOD...THOUGH A FEW GUSTS TO 15
KTS WILL BE POSSIBLE OVER THE NEXT COUPLE OF HOURS AND AGAIN LATE
MONDAY EVENING AS THAT NEXT BOUNDARY CLOSES IN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...ABE
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
115 AM EDT MON APR 15 2013
.UPDATE...
ISSUED AT 105 AM EDT MON APR 15 2013
UPDATED THE FORECAST TO BETTER REFLECT THE ON-GOING MEASURABLE RAIN
OVER THE NORTHEAST PORTION OF THE CWA. THIS RAIN HAS ALSO KNOCKED
DOWN TEMPERATURES...WAY OFF OF OUR FORECAST DIURNAL TRACK SO THAT
THEY ARE NEAR THE LOWS IN THE SOUTH WHILE STILL DECENT IN THE NORTH.
HAVE ADDRESSED THIS AS WELL WITH THIS UPDATE. LIKEWISE...DECIDED TO
LOAD IN THE LATEST TD GRIDS FROM THE HRRR AS THE OTHER GUIDANCE IS
PRETTY FAR OFF...ASIDE FROM THE GMOS. THE LIGHT RAIN WILL PIVOT OUT
OF THE AREA BY DAWN...LINGERING THE LONGEST OVER OUR FAR EASTERN
TERRITORY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. A
FRESH SET OF ZONES WILL FOLLOW SHORTLY.
UPDATE ISSUED AT 1143 PM EDT SUN APR 14 2013
HAD TO MAKE ANOTHER QUICK UPDATE TO THE FORECAST. SURFACE
OBSERVATIONS FROM LOCATIONS SOUTH AND SOUTHEAST OF THE WEATHER OFFICE
HAVE PICKED UP ENOUGH RAIN OVER THE PAST FEW HOURS TO WARRANT HIGHER
THAN SLIGHT CHANCE POPS. A NUMBER OF RAWS...AWOS...AND OTHER
OBSERVATIONS SITES FROM WAYNE COUNTY EASTWARD TO LETCHER COUNTY HAVE
MEASURED AT LEAST A FEW HUNDREDTHS OF AN INCH OF RAIN SINCE 8 PM.
THEREFORE...DECIDED TO INCREASE PRECIPITATION CHANCES FOR THE 2 TO 6Z
TIME FRAME TONIGHT TO BETTER REFLECT ACTUAL TRENDS IN THE WEATHER.
THE APPROPRIATE CHANGES WERE MADE TO THE QPF AND WEATHER GRIDS AS
WELL BASED ON THE NEW POP FORECAST. THE REST OF THE FORECAST WAS IN
GOOD SHAPE AS IS.
UPDATE ISSUED AT 927 PM EDT SUN APR 14 2013
WITH MEASURABLE PRECIPITATION ALREADY OCCURRING BETWEEN THE TENNESSEE
BORDER AND THE HAL ROGERS PARKWAY HIGHWAY 80 CORRIDOR...WAS NECESSARY
TO UPDATE THE FORECAST TO REFLECT THE CURRENT TRENDS AND CONDITIONS.
IN A NUTSHELL...MEASURABLE PRECIPITATION IS OCCURRING EARLIER AND A
BIT FURTHER NORTH THEN THE INHERITED FORECAST WAS INDICATING...SO THE
APPROPRIATE CHANGES HAVE BEEN MADE TO BOTH THE GRIDS AND THE ZONE
FORECAST TEXT PRODUCT. THE TEMPERATURES...WIND...AND SKY COVER
FORECAST ELEMENTS ARE ALL ON TRACK FOR THE NIGHT...SO NO CHANGES WERE
MADE TO ANY OF THOSE. THE UPDATED FORECAST HAS ALREADY BEEN ISSUED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 331 PM EDT SUN APR 14 2013
HIGH CLOUDS CONTINUE TO STREAM IN FROM THE SOUTHWEST OUT AHEAD OF A
SHORT WAVE TROUGH SWINGING THROUGH THE GULF COAST STATES. THE MODELS
ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM...SWINGING THIS WAVE
NORTHEAST ACROSS THE SOUTHERN APPALACHIANS TONIGHT...BEFORE EXITING
ACROSS THE MID-ATLANTIC ON MONDAY...WITH WEAK RIDGING TO FOLLOW
ACROSS THE EASTERN SEABOARD.
THE MODELS HAVE TRENDED A BIT MORE AGGRESSIVE WITH THE POPS ACROSS
SOUTHEASTERN KENTUCKY TONIGHT. GIVEN THE AGREEMENT...INCREASED POPS
SOMEWHAT...ALTHOUGH WITH THE CURRENT LOW LEVEL DRY AIR IN PLACE...AM
NOT TOO CONFIDENT THIS FAIRLY FAST MOVING SYSTEM WILL BE ABLE TO
SATURATE THE LOW LEVELS IN TIME FOR MEASURABLE PRECIPITATION.
THE THICKER CLOUDS WILL MITIGATE THE RIDGE/VALLEY SPLIT TONIGHT...WITH
MOST LOCATIONS BOTTOMING OUT IN THE LOW TO MID 50S. CLOUDS WILL BE ON
THE DECREASE BY MONDAY AFTERNOON AS SOME SHORT WAVE RIDGING FOLLOWS
IN THE WAKE OF THE EXITING SHORT WAVE TROUGH. HIGHS WILL REBOUND TO
THE MID AND UPPER 70S.
FOR MONDAY NIGHT...A WEAKENING COLD FRONT WILL ATTEMPT TO APPROACH
FROM THE NORTHWEST...BUT LOOKS TO STAY NORTH OF THE OHIO RIVER. WILL
CONTINUE WITH JUST A SLIGHT CHANCE OF A SHOWER OR STORM THREATENING
THE BLUEGRASS LATE. CLOUDS WILL BE LESS EXTENSIVE MONDAY NIGHT...AND
WITH LIGHT SOUTHERLY WINDS...THIS SHOULD SET UP MORE A RIDGE/VALLEY
SPLIT. COOLER VALLEYS WILL BOTTOM OUT IN THE LOWER 50S...WHILE RIDGES
STAY UP AT AROUND 60.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 331 PM EDT SUN APR 14 2013
MODEL FORECASTS HAVE TRENDED A BIT WETTER SINCE YESTERDAY FOR THE
EARLY PART OF THE FORECAST PERIOD. MOIST GULF OF MEXICO AIR SHOULD
BE IN PLACE LOCALLY...ON THE SOUTH SIDE OF A FRONT STALLING OUT NEAR
THE OHIO RIVER ON TUESDAY. A WEAK SHORTWAVE TROUGH RIPPLING EAST
OVER THE REGION MAY AID DEVELOPMENT OF SHOWERS/THUNDERSTORMS ON
TUESDAY. AS THE WAVE MOVES AWAY AND HEATING IS LOST...WILL LOOK FOR
A DECREASE IN PRECIP ON TUESDAY NIGHT. HEATING ON WEDNESDAY MAY GET
SOME MORE SHOWERS/THUNDERSTORMS GOING...POSSIBLY AIDED BY ANOTHER
VERY WEAK WAVE. ON BOTH DAYS...WILL CARRY THE HIGHEST POPS IN THE
NORTHERN PART OF THE AREA CLOSEST TO THE SURFACE FRONT. THIS SHOULD
BE FOLLOWED BY ANOTHER PRECIP LULL WITH LOSS OF HEATING ON WEDNESDAY
NIGHT.
BY THURSDAY THE STALLED FRONTAL BOUNDARY SHOULD HAVE LIFTED MUCH
FURTHER NORTH...BEING DRIVEN BY A LOW PRESSURE SYSTEM TRACKING NE
OVER THE MIDWEST. WILL NOT RULE OUT SHOWERS/THUNDERSTORMS DEVELOPING
ON THURSDAY...BUT BOTH THE GFS AND ECMWF FOCUS THE BULK OF THE
PRECIP CLOSER TO THE FRONTAL BOUNDARIES TO OUR NORTH AND WEST. THE
12Z GFS DEVELOPS AN ADDITIONAL LOW PRESSURE SYSTEM ALONG THE FRONT
OVER THE MIDWEST LATE THURSDAY AND THURSDAY NIGHT...LEADING TO A
SLIGHTLY SLOWER MOVEMENT OF A STRONG LATE WEEK COLD FRONT AS
COMPARED TO EARLIER RUNS OF THE GFS OR ECMWF. EVEN SO...THE 12Z GFS
IS ONLY ABOUT 4-5 HOURS SLOWER THAN THE CONSISTENT EARLIER RUNS.
THAT BEING THE CASE...WILL STILL OPT FOR FROPA ON FRIDAY
MORNING...WHICH WOULD LIKELY YIELD TEMPS BELOW GFS MOS GUIDANCE ON
FRIDAY. HIGHEST POPS OF THE LONG TERM WILL BE IN LIKELY CATEGORY
NEAR AND BEHIND THE COLD FRONT. IT SHOULD STILL EXIT TO THE EAST BY
FRIDAY NIGHT...LEAVING DRY AND MUCH COOLER WEATHER TO FINISH THE
PERIOD. IN FACT...FROST AGAIN LOOKS LIKE IT COULD BE A CONCERN NEXT
WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 115 AM EDT MON APR 15 2013
THE SFC WAVE PASSING BY TO THE SOUTHEAST WILL CLEAR OUT THE LIGHT
RAIN FROM THE TAF SITES DURING THE EARLY MORNING HOURS AND THE REST
OF THE AREA BY DAWN. EVEN AS THE WX IMPROVES...THE CIGS WILL PROBABLY
BRIEFLY FALL TO MVFR AROUND DAWN. THE WAVE WILL EVENTUALLY GET FAR
ENOUGH EAST TO ALLOW CIGS TO CLIMB OR CLEAR OUT ENTIRELY RESUMING THE
VFR CONDITIONS BY MID MORNING MONDAY. THIS SHOULD BE THE CASE THROUGH
EVENING...THOUGH CIGS WILL LIKELY RETURN AND LOWER TOWARDS MIDNIGHT
AHEAD OF A SAGGING FRONT FROM THE NORTHWEST. WINDS WILL BE GENERALLY
LIGHT FROM THE SOUTH THROUGH THE PERIOD...THOUGH A FEW GUSTS TO 15
KTS WILL BE POSSIBLE OVER THE NEXT COUPLE OF HOURS AND AGAIN LATE
MONDAY EVENING AS THAT NEXT BOUNDARY CLOSES IN.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...HAL
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
537 AM EDT MON APR 15 2013
.SYNOPSIS...
HIGH PRESSURE WILL BE IN PLACE TODAY WITH FAIR WEATHER EXPECTED. A
COLD FRONT APPROACHES FROM THE WEST TUESDAY...BRINGING WITH IT
SHOWERS. HIGH PRESSURE BUILDS IN FROM THE NORTH DURING THE DAY
WEDNESDAY INTO WEDNESDAY NIGHT. A WARM FRONT LIFTS NORTH ACROSS
THE REGION ON THURSDAY. ANOTHER COLD FRONT SLOWLY MOVES ACROSS THE
REGION FRIDAY THROUGH SATURDAY...PRODUCING ANOTHER THREAT FOR
SHOWERS. COOLER HIGH PRESSURE BUILDS IN ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...A FEW CHANGES TO REFLECT CURRENT OBSERVATIONAL TRENDS.
BACKDOOR COLD FNT LIKE FEATURE IS SPREADING LOW CLOUDS INTO
DOWNEAST ATTM. TIME OF ARRIVAL TOOL AS WELL AS LATEST HRRR BRING
THIS DECK INTO THE WRN PENOBSCOT BAY AREA AROUND 12Z BEFORE
SCATTERING OUT. HAVE UPDATED THE SKY GRIDS TO REFLECT THIS.
PREVIOUS DISCUSSION...HIGH PRES HAS SETTLED ACROSS THE NORTHEAST
THIS MORNING. THIS SHOULD KEEP CLOUDS ASSOCIATED WITH LIFTING WARM
FNT MOSTLY AT BAY...EXCEPT FOR SOME HIGH...THIN CLOUDINESS.
WEAK PRES GRADIENT WILL ALLOW FOR SEA BREEZE TO DEVELOP WITH
DAYTIME HEATING. THIS ONSHORE FLOW WILL MOST AFFECT WRN ME. THIS
WILL KEEP TEMPS IN THE 50S...WHILE SLY FLOW AND MOSTLY SUNNY SKIES
ACROSS NH WILL BRING SRN AREAS TO NEAR 60. BLENDED IN THE LOCAL
WRF TEMPS TO TRACK PROGRESS OF SEA BREEZE FNT INLAND DURING THE
DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MID LVL WARM FNT WILL CONTINUE LIFTING ACROSS THE AREA TONIGHT.
CLOUDS WILL GENERALLY BE OF A MID TO HIGH LVL VARIETY...SO PLAYED
THEM DOWN A LITTLE IN THE GRIDS AS THE IMPACT SHOULD BE MINOR.
WARM FNT CONTINUES TO LIFT THRU THE CWAF TUE...BUT MODEL GUIDANCE
CAN GET OVERLY AGGRESSIVE IN BRINGING THESE FEATURES NWD THIS TIME
OF YEAR. HOWEVER...IN THIS CASE NWP HAS A NICE CONSENSUS OF THE
FNT HANGING UP AROUND THE MIDCOAST AND STRUGGLING TO BRING SFC
WARMTH THAT FAR N. AS SUCH A MAV/MET/ECMWF MOS BLEND LOOKED GOOD
FOR TEMPS. ALSO BACKED OFF THE TIMING OF PCPN INTO THE AREA SOME.
PREFER LEAVING TUE MOSTLY DRY OUTSIDE OF SHWRS IN THE MTNS DURING
THE DAY. IT ISN/T UNTIL LATER IN THE AFTN THAT SHWRS WILL ENCROACH
UPON THE COAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MODELS ARE IN DECENT AGREEMENT THROUGH LATE IN THE WEEKEND. WE
BEGIN THE PERIOD WITH A SHORTWAVE CROSSING QUEBEC AND AN ASSOCIATED
COLD FRONT CROSSING THE FORECAST AREA. IN THE WAKE OF THIS SYSTEM...A
BUILDING EASTERN RIDGE WITH A DOWNSTREAM UPPER TROUGH OVER THE ROCKIES.
MILD AND INCREASINGLY UNSETTLED THROUGH SATURDAY AS THE UPPER TROUGH
SHEARS OUT AND DRIVES A STRONG COLD FRONT ACROSS THE AREA DURING THE
FIRST HALF OF THE WEEKEND. IN THE DAILIES...HIGH PRESSURE WILL BUILD
SOUTH AND EAST INTO NEW ENGLAND FOR WEDNESDAY AND WEDNESDAY NIGHT.
LOW PRESSURE PASSING TO OUR WEST WILL DRAG A WARM FRONT NORTH ACROSS
THE REGION THURSDAY. A SLOW-MOVING COLD FRONT WILL APPROACH THE
AREA LATE FRIDAY AND FRIDAY NIGHT THEN EXIT THE COAST ON SATURDAY.
HIGH PRESSURE AND DRY AIR BUILDS EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
SHORT TERM...VFR CONDS EXPECTED TO PREVAIL TODAY. IFR OR LOWER
CIGS MAY IMPACT KRKD EARLY THIS MORNING BEFORE SCATTERING OUT THIS
AFTERNOON. PATCHY VALLEY FOG IS PSBL AGAIN BUT NOT AS WIDESPREAD
AS YESTERDAY MORNING. TUE AFTERNOON MVFR CONDS WILL WORK INTO THE
AREA FROM NW TO SE AS COLD FNT APPROACHES. CLOUDS AND SHWRS WILL
CONTINUE WORKING SE THRU THE REST OF THE DAY.
LONG TERM...
TUE - TUE NIGHT...AREAS OF MVFR IN RAIN SHOWERS.
FRI...SCT MVFR IN SHOWERS...WITH LCL IFR POSSIBLE VCNTY OF THE
COAST IN STRATUS AND FOG.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SCA THRESHOLDS
THRU TONIGHT. WINDS AND SEAS THEN INCREASE AS SWLY FLOW DEVELOPS
AHEAD OF APPROACHING COLD FNT. INVERSION OVER THE WATERS WILL
TEMPER WIND GUSTS SOMEWHAT...BUT SEAS WILL LIKELY BUILD OVER SCA
THRESHOLDS.
LONG TERM...
TUE NIGHT...GALE FORCE WINDS ARE POSSIBLE.
THU NIGHT - FRI...GALE FORCE WINDS ARE POSSIBLE.
&&
.FIRE WEATHER...
FIRE WEATHER DANGER WILL REMAIN LOW TODAY. COOLER...ONSHORE FLOW
WILL KEEP RH VALUES ABOVE 35 PERCENT. TEMPS WARM AND WINDS
INCREASE TUE...BUT THE CHANCE FOR WETTING RAINS WILL ALSO BE ON
THE INCREASE AS A COLD FNT APPROACHES FROM THE NW.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...LEGRO
SHORT TERM...LEGRO
LONG TERM...SCHWIBS
AVIATION...LEGRO/SCHWIBS
MARINE...LEGRO/SCHWIBS
FIRE WEATHER...LEGRO
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
657 AM EDT MON APR 15 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER SOUTHWEST VIRGINIA IS TRACKING
INTO THE MID ATLANTIC REGION THIS MORNING. A COLD FRONT WILL APPROACH THE
AREA TUESDAY BEFORE STALLING OVERHEAD WEDNESDAY. THIS BOUNDARY
WILL RETURN NORTH AS A WARM FRONT THURSDAY BEFORE A STRONGER COLD
FRONT MOVES IN FROM THE WEST LATE FRIDAY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON CURRENT OBS/RDR HV INCRSD THE POPS IN THE CENTRAL SHEN
VLLY TO CAT FOR THE MRNG HRS. QPF SHOULD ONLY BE A FEW HUNDRETHS
OF AN INCH BUT THIS IS MORE THAN "CHC" SHOULD BE HANDLING. RA IS
CURRENTLY TRACKING INTO NOVA. POPS WERE INCRSD/NOWCAST IN EFFECT.
PRVS DSCN...
HIGH PRES HAS MOVED FAR ENOUGH OFFSHORE THAT ITS INFLUENCE APPEARS
TO BE WANING IN THE MID ATLC. EVEN THO THE 00Z RNK AND IAD SNDGS
WERE QUITE DRY THIS IS BEING OVERCOME BY MOISTURE W/ THE APRCHG
SHORT WV. AS A RESULT ENTIRE AREA HAS GONE OVC AND THE RAFL ASSO W/
THE UPR LVL SHORT WV HAS PUSHED N OF CHO. BOTH GFS AND NAM ARE
GIVING CHC POPS TO THE ENTIRE RGN TDA...AND HV MADE THAT
ADJUSTMENT W/ THE XCPTN OF LKLY POPS IN THE CENTRAL SHEN VLLY.
QUSTN THEN BECOMES WHAT TIME IS THE BEST FOR MEASURABLE PCPN.
GIVEN CURRENT PCPN MVMNT...AND THE HRRR/LAV PROJECTION FEEL THE
MRNG HRS HV THE BETTER CHC - HRRR IMPLIES THE PCPN BRKG UP THIS
AFTN. REGARDLESS SKIES WL BE CLDY TDA W/ ONLY VERY LOW QPF AMTS.
HIGH TEMPS GNRLY IN M60S XCPT COOLER IN THE HIGHLANDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
CLDY SKIES XPCTD TO CONT TNGT FM THE FLOW OFF THE OCEAN DUE TO THE
HIGH OVR ATLC CANADA. NOT MUCH OF A DIURNAL TEMP SPREAD - LOWS IN
THE LML50S XCPT 40S IN THE HIGHLANDS. PCPN WOULD BE LGT AND
SPOTTY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY BEFORE
MOVING OUT TO SEA TUESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH
PENNSYLVANIA TUESDAY BEFORE MOVING INTO NORTHERN MARYLAND LATE
TUESDAY NIGHT.
AN ONSHORE FLOW AROUND THE SURFACE HIGH WILL CAUSE LOW CLOUDS ALONG
WITH OCCASIONAL DRIZZLE TUESDAY MORNING. THE BEST CHANCE FOR DRIZZLE
WILL BE NORTH AND WEST OF THE I-95 CORRIDOR WHERE THE SUBSIDENCE
INVERSION WILL BE HIGHER. A STRENGTHENING PRESSURE GRADIENT BETWEEN
THE APPROACHING COLD FRONT AND THE DEPARTING HIGH SHOULD CAUSE
ENOUGH OF A GRADIENT TO MIX OUT THE MARINE LAYER TUESDAY AFTERNOON.
THERE SHOULD BE ENOUGH BREAKS OF SUNSHINE FOR MAX TEMPS TO REACH THE
70S ACROSS MOST LOCATIONS. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...WHERE THE
SUBSIDENCE INVERSION WILL BE WEAKEST.
THE COLD FRONT WILL CONTINUE TO DROP SOUTH THROUGH PENNSYLVANIA
TUESDAY EVENING BEFORE MOVING INTO NORTHERN MARYLAND OVERNIGHT. WARM
CONDITIONS ARE EXPECTED AHEAD OF THE BOUNDARY AND SHOWERS ARE
POSSIBLE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE CWA. MIN
TEMPS WILL RANGE FROM THE MIDDLE 50S IN NORTHERN MARYLAND AND THE
POTOMAC HIGHLANDS TO THE LOWER 60S IN DOWNTOWN WASHINGTON AND
BALTIMORE.
THE COLD FRONT WILL STALL OUT OVER THE REGION WEDNESDAY INTO
THURSDAY BEFORE MOVING NORTH AS A WARM FRONT LATER THURSDAY AND
THURSDAY NIGHT. THE EXACT POSITION OF THE BOUNDARY REMAINS UNCERTAIN
AT THIS TIME WHICH MEANS THAT THERE IS A LOW CERTAINTY IN THE
FORECAST. THE BOUNDARY WILL SEPARATE COOL MARINE AIR TO THE NORTH
AND EAST FROM A WARM AND MOIST AIRMASS TO THE SOUTH AND WEST.
SHOWERS AND T-STORMS ARE POSSIBLE ALONG AND AHEAD OF THE
BOUNDARY...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH
DAY.
A STRONGER COLD FRONT WILL APPROACH THE AREA FRIDAY BEFORE MOVING
THROUGH FRIDAY NIGHT. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG AND AHEAD OF THIS BOUNDARY. THUNDERSTORMS WILL HAVE
THE POTENTIAL TO PRODUCE GUSTY WINDS. CANADIAN HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
OVC SKIES TDA BUT CIGS XPCTD TO RMN ABV LOW VFR LVLS. LGT RA XPCTD
AT TAF SITES THIS MRNG BUT DRY THIS AFTN.
LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE WILL IMPACT THE
TERMINALS TUESDAY MORNING. IFR CONDITIONS ARE EXPECTED. CIGS/VSBYS
WILL IMPROVE TUESDAY AFTERNOON. A COLD FRONT WILL APPROACH THE
TERMINALS TUESDAY NIGHT BEFORE STALLING OVERHEAD WEDNESDAY INTO
THURSDAY. SHOWERS AND T-STORMS ARE POSSIBLE WEDNESDAY AND
THURSDAY. A STRONGER COLD FRONT WILL APPROACH THE TERMINALS LATER
FRIDAY AND FRIDAY NIGHT. WIDESPREAD SHOWERS/THUNDERSTORMS ARE
POSSIBLE. SOME THUNDERSTORMS MAY CONTAIN GUSTY WINDS.
&&
.MARINE...
MARGINAL SCA IN EFFECT FOR THE AFTN HRS TDA.
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY WHILE A
COLD FRONT APPROACHES FROM PENNSYLVANIA. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE WATERS TUESDAY AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS TUESDAY NIGHT. THE COLD FRONT WILL
STALL OVER THE WATERS WEDNESDAY INTO THURSDAY. A STRONGER COLD FRONT
WILL APPROACH THE WATERS FRIDAY BEFORE PASSING THROUGH FRIDAY NIGHT.
SHOWERS AND T-STORMS AHEAD OF THIS BOUNDARY MAY BECOME MORE
WIDESPREAD AND GUSTY WINDS ARE POSSIBLE IN ANY THUNDERSTORMS THAT
DEVELOP.
&&
.TIDES/COASTAL FLOODING...
AT THE MOMENT WATER LVLS IN THE BAY ARE SLTLY ABV NRML...BUT NOT
HIGH ENOUGH TO WARRANT AN ADVSRY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT TUESDAY FOR
ANZ530>543.
&&
$$
PRODUCTS...WOODY!/BJL
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
521 AM EDT MON APR 15 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER SOUTHWEST VIRGINIA IS TRACKING
INTO THE MID ATLANTIC REGION THIS MORNING. A COLD FRONT WILL APPROACH THE
AREA TUESDAY BEFORE STALLING OVERHEAD WEDNESDAY. THIS BOUNDARY
WILL RETURN NORTH AS A WARM FRONT THURSDAY BEFORE A STRONGER COLD
FRONT MOVES IN FROM THE WEST LATE FRIDAY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
BASED ON CURRENT OBS/RDR HV INCRSD THE POPS IN THE CENTRAL SHEN
VLLY TO CAT FOR THE MRNG HRS. QPF SHOULD ONLY BE A FEW HUNDRETHS
OF AN INCH BUT THIS IS MORE THAN "CHC" SHOULD BE HANDLING.
PRVS DSCN...
HIGH PRES HAS MOVED FAR ENOUGH OFFSHORE THAT ITS INFLUENCE APPEARS
TO BE WANING IN THE MID ATLC. EVEN THO THE 00Z RNK AND IAD SNDGS
WERE QUITE DRY THIS IS BEING OVERCOME BY MOISTURE W/ THE APRCHG
SHORT WV. AS A RESULT ENTIRE AREA HAS GONE OVC AND THE RAFL ASSO W/
THE UPR LVL SHORT WV HAS PUSHED N OF CHO. BOTH GFS AND NAM ARE
GIVING CHC POPS TO THE ENTIRE RGN TDA...AND HV MADE THAT
ADJUSTMENT W/ THE XCPTN OF LKLY POPS IN THE CENTRAL SHEN VLLY.
QUSTN THEN BECOMES WHAT TIME IS THE BEST FOR MEASURABLE PCPN.
GIVEN CURRENT PCPN MVMNT...AND THE HRRR/LAV PROJECTION FEEL THE
MRNG HRS HV THE BETTER CHC - HRRR IMPLIES THE PCPN BRKG UP THIS
AFTN. REGARDLESS SKIES WL BE CLDY TDA W/ ONLY VERY LOW QPF AMTS.
HIGH TEMPS GNRLY IN M60S XCPT COOLER IN THE HIGHLANDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
CLDY SKIES XPCTD TO CONT TNGT FM THE FLOW OFF THE OCEAN DUE TO THE
HIGH OVR ATLC CANADA. NOT MUCH OF A DIURNAL TEMP SPREAD - LOWS IN
THE LML50S XCPT 40S IN THE HIGHLANDS. PCPN WOULD BE LGT AND
SPOTTY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY BEFORE
MOVING OUT TO SEA TUESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH
PENNSYLVANIA TUESDAY BEFORE MOVING INTO NORTHERN MARYLAND LATE
TUESDAY NIGHT.
AN ONSHORE FLOW AROUND THE SURFACE HIGH WILL CAUSE LOW CLOUDS ALONG
WITH OCCASIONAL DRIZZLE TUESDAY MORNING. THE BEST CHANCE FOR DRIZZLE
WILL BE NORTH AND WEST OF THE I-95 CORRIDOR WHERE THE SUBSIDENCE
INVERSION WILL BE HIGHER. A STRENGTHENING PRESSURE GRADIENT BETWEEN
THE APPROACHING COLD FRONT AND THE DEPARTING HIGH SHOULD CAUSE
ENOUGH OF A GRADIENT TO MIX OUT THE MARINE LAYER TUESDAY AFTERNOON.
THERE SHOULD BE ENOUGH BREAKS OF SUNSHINE FOR MAX TEMPS TO REACH THE
70S ACROSS MOST LOCATIONS. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...WHERE THE
SUBSIDENCE INVERSION WILL BE WEAKEST.
THE COLD FRONT WILL CONTINUE TO DROP SOUTH THROUGH PENNSYLVANIA
TUESDAY EVENING BEFORE MOVING INTO NORTHERN MARYLAND OVERNIGHT. WARM
CONDITIONS ARE EXPECTED AHEAD OF THE BOUNDARY AND SHOWERS ARE
POSSIBLE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE CWA. MIN
TEMPS WILL RANGE FROM THE MIDDLE 50S IN NORTHERN MARYLAND AND THE
POTOMAC HIGHLANDS TO THE LOWER 60S IN DOWNTOWN WASHINGTON AND
BALTIMORE.
THE COLD FRONT WILL STALL OUT OVER THE REGION WEDNESDAY INTO
THURSDAY BEFORE MOVING NORTH AS A WARM FRONT LATER THURSDAY AND
THURSDAY NIGHT. THE EXACT POSITION OF THE BOUNDARY REMAINS UNCERTAIN
AT THIS TIME WHICH MEANS THAT THERE IS A LOW CERTAINTY IN THE
FORECAST. THE BOUNDARY WILL SEPARATE COOL MARINE AIR TO THE NORTH
AND EAST FROM A WARM AND MOIST AIRMASS TO THE SOUTH AND WEST.
SHOWERS AND T-STORMS ARE POSSIBLE ALONG AND AHEAD OF THE
BOUNDARY...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH
DAY.
A STRONGER COLD FRONT WILL APPROACH THE AREA FRIDAY BEFORE MOVING
THROUGH FRIDAY NIGHT. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG AND AHEAD OF THIS BOUNDARY. THUNDERSTORMS WILL HAVE
THE POTENTIAL TO PRODUCE GUSTY WINDS. CANADIAN HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE WILL IMPACT THE TERMINALS
TUESDAY MORNING. IFR CONDITIONS ARE EXPECTED. CIGS/VSBYS WILL
IMPROVE TUESDAY AFTERNOON. A COLD FRONT WILL APPROACH THE TERMINALS
TUESDAY NIGHT BEFORE STALLING OVERHEAD WEDNESDAY INTO THURSDAY.
SHOWERS AND T-STORMS ARE POSSIBLE WEDNESDAY AND THURSDAY. A STRONGER
COLD FRONT WILL APPROACH THE TERMINALS LATER FRIDAY AND FRIDAY
NIGHT. WIDESPREAD SHOWERS/THUNDERSTORMS ARE POSSIBLE. SOME
THUNDERSTORMS MAY CONTAIN GUSTY WINDS.
&&
.MARINE...
MARGINAL SCA IN EFFECT FOR THE AFTN HRS TDA.
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY WHILE A
COLD FRONT APPROACHES FROM PENNSYLVANIA. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE WATERS TUESDAY AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS TUESDAY NIGHT. THE COLD FRONT WILL
STALL OVER THE WATERS WEDNESDAY INTO THURSDAY. A STRONGER COLD FRONT
WILL APPROACH THE WATERS FRIDAY BEFORE PASSING THROUGH FRIDAY NIGHT.
SHOWERS AND T-STORMS AHEAD OF THIS BOUNDARY MAY BECOME MORE
WIDESPREAD AND GUSTY WINDS ARE POSSIBLE IN ANY THUNDERSTORMS THAT
DEVELOP.
&&
.TIDES/COASTAL FLOODING...
AT THE MOMENT WATER LVLS IN THE BAY ARE SLTLY ABV NRML...BUT NOT
HIGH ENOUGH TO WARRANT AN ADVSRY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT TUESDAY FOR
ANZ530>543.
&&
$$
PRODUCTS...WOODY!/BJL
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
341 AM EDT MON APR 15 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE OVER SOUTHWEST VIRGINIA IS TRACKING
INTO THE MID ATLANTIC REGION THIS MORNING. A COLD FRONT WILL APPROACH THE
AREA TUESDAY BEFORE STALLING OVERHEAD WEDNESDAY. THIS BOUNDARY
WILL RETURN NORTH AS A WARM FRONT THURSDAY BEFORE A STRONGER COLD
FRONT MOVES IN FROM THE WEST LATE FRIDAY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /TODAY/...
HIGH PRES HAS MOVED FAR ENOUGH OFFSHORE THAT ITS INFLUENCE APPEARS
TO BE WANING IN THE MID ATLC. EVEN THO THE 00Z RNK AND IAD SNDGS
WERE QUITE DRY THIS IS BEING OVERCOME BY MOISTURE W/ THE APRCHG
SHORT WV. AS A RESULT ENTIRE AREA HAS GONE OVC AND THE RAFL ASSO W/
THE UPR LVL SHORT WV HAS PUSHED N OF CHO. BOTH GFS AND NAM ARE
GIVING CHC POPS TO THE ENTIRE RGN TDA...AND HV MADE THAT
ADJUSTMENT W/ THE XCPTN OF LKLY POPS IN THE CENTRAL SHEN VLLY.
QUSTN THEN BECOMES WHAT TIME IS THE BEST FOR MEASURABLE PCPN.
GIVEN CURRENT PCPN MVMNT...AND THE HRRR/LAV PROJECTION FEEL THE
MRNG HRS HV THE BETTER CHC - HRRR IMPLIES THE PCPN BRKG UP THIS
AFTN. REGARDLESS SKIES WL BE CLDY TDA W/ ONLY VERY LOW QPF AMTS.
HIGH TEMPS GNRLY IN M60S XCPT COOLER IN THE HIGHLANDS.
&&
.SHORT TERM /TONIGHT/...
CLDY SKIES XPCTD TO CONT TNGT FM THE FLOW OFF THE OCEAN DUE TO THE
HIGH OVR ATLC CANADA. NOT MUCH OF A DIURNAL TEMP SPREAD - LOWS IN
THE LML50S XCPT 40S IN THE HIGHLANDS. PCPN WOULD BE LGT AND
SPOTTY.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY BEFORE
MOVING OUT TO SEA TUESDAY NIGHT. A COLD FRONT WILL MOVE THROUGH
PENNSYLVANIA TUESDAY BEFORE MOVING INTO NORTHERN MARYLAND LATE
TUESDAY NIGHT.
AN ONSHORE FLOW AROUND THE SURFACE HIGH WILL CAUSE LOW CLOUDS ALONG
WITH OCCASIONAL DRIZZLE TUESDAY MORNING. THE BEST CHANCE FOR DRIZZLE
WILL BE NORTH AND WEST OF THE I-95 CORRIDOR WHERE THE SUBSIDENCE
INVERSION WILL BE HIGHER. A STRENGTHENING PRESSURE GRADIENT BETWEEN
THE APPROACHING COLD FRONT AND THE DEPARTING HIGH SHOULD CAUSE
ENOUGH OF A GRADIENT TO MIX OUT THE MARINE LAYER TUESDAY AFTERNOON.
THERE SHOULD BE ENOUGH BREAKS OF SUNSHINE FOR MAX TEMPS TO REACH THE
70S ACROSS MOST LOCATIONS. A FEW SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...WHERE THE
SUBSIDENCE INVERSION WILL BE WEAKEST.
THE COLD FRONT WILL CONTINUE TO DROP SOUTH THROUGH PENNSYLVANIA
TUESDAY EVENING BEFORE MOVING INTO NORTHERN MARYLAND OVERNIGHT. WARM
CONDITIONS ARE EXPECTED AHEAD OF THE BOUNDARY AND SHOWERS ARE
POSSIBLE ACROSS THE NORTHERN AND WESTERN PORTIONS OF THE CWA. MIN
TEMPS WILL RANGE FROM THE MIDDLE 50S IN NORTHERN MARYLAND AND THE
POTOMAC HIGHLANDS TO THE LOWER 60S IN DOWNTOWN WASHINGTON AND
BALTIMORE.
THE COLD FRONT WILL STALL OUT OVER THE REGION WEDNESDAY INTO
THURSDAY BEFORE MOVING NORTH AS A WARM FRONT LATER THURSDAY AND
THURSDAY NIGHT. THE EXACT POSITION OF THE BOUNDARY REMAINS UNCERTAIN
AT THIS TIME WHICH MEANS THAT THERE IS A LOW CERTAINTY IN THE
FORECAST. THE BOUNDARY WILL SEPARATE COOL MARINE AIR TO THE NORTH
AND EAST FROM A WARM AND MOIST AIRMASS TO THE SOUTH AND WEST.
SHOWERS AND T-STORMS ARE POSSIBLE ALONG AND AHEAD OF THE
BOUNDARY...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS EACH
DAY.
A STRONGER COLD FRONT WILL APPROACH THE AREA FRIDAY BEFORE MOVING
THROUGH FRIDAY NIGHT. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG AND AHEAD OF THIS BOUNDARY. THUNDERSTORMS WILL HAVE
THE POTENTIAL TO PRODUCE GUSTY WINDS. CANADIAN HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
LOW CLOUDS ALONG WITH OCCASIONAL DRIZZLE WILL IMPACT THE TERMINALS
TUESDAY MORNING. IFR CONDITIONS ARE EXPECTED. CIGS/VSBYS WILL
IMPROVE TUESDAY AFTERNOON. A COLD FRONT WILL APPROACH THE TERMINALS
TUESDAY NIGHT BEFORE STALLING OVERHEAD WEDNESDAY INTO THURSDAY.
SHOWERS AND T-STORMS ARE POSSIBLE WEDNESDAY AND THURSDAY. A STRONGER
COLD FRONT WILL APPROACH THE TERMINALS LATER FRIDAY AND FRIDAY
NIGHT. WIDESPREAD SHOWERS/THUNDERSTORMS ARE POSSIBLE. SOME
THUNDERSTORMS MAY CONTAIN GUSTY WINDS.
&&
.MARINE...
MARGINAL SCA IN EFFECT FOR THE AFTN HRS TDA.
HIGH PRESSURE WILL REMAIN OFF THE NEW ENGLAND COAST TUESDAY WHILE A
COLD FRONT APPROACHES FROM PENNSYLVANIA. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE WATERS TUESDAY AND THE SMALL CRAFT ADVISORY MAY BE
NEEDED FOR PORTIONS OF THE WATERS TUESDAY NIGHT. THE COLD FRONT WILL
STALL OVER THE WATERS WEDNESDAY INTO THURSDAY. A STRONGER COLD FRONT
WILL APPROACH THE WATERS FRIDAY BEFORE PASSING THROUGH FRIDAY NIGHT.
SHOWERS AND T-STORMS AHEAD OF THIS BOUNDARY MAY BECOME MORE
WIDESPREAD AND GUSTY WINDS ARE POSSIBLE IN ANY THUNDERSTORMS THAT
DEVELOP.
&&
.TIDES/COASTAL FLOODING...
AT THE MOMENT WATER LVLS IN THE BAY ARE SLTLY ABV NRML...BUT NOT
HIGH ENOUGH TO WARRANT AN ADVSRY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EDT THIS EVENING
FOR ANZ530>543.
SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT TUESDAY FOR
ANZ530>543.
&&
$$
PRODUCTS...WOODY!/BAJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
737 PM EDT TUE APR 16 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NRN QUEBEC THROUGH JAMES BAY INTO NRN ONTARIO WAS DEPARTING TO THE
EAST. UPSTREAM...SW FLOW PREVAILED THROUGH THE PLAINS AHEAD OF A
TROUGH FROM THE NRN ROCKIES THROUGH THE GREAT BASIN. WITH CONFLUENT
FLOW WITH QVECTOR DIV AND SUBSIDENCE OVER THE NRN GREAT LAKES...THE
SCT FLURRIES HAD DIMINISHED THIS AFTERNOON.
AS HIGH PRES BUILDS INTO NRN ONTARIO TONIGHT BRINGING ENE ACYC FLOW
INTO UPPER MI AND DAYTIME HEATING FADES...EXPECT THAT WINDS WILL
DIMINISH AND CLOUDS WILL THIN OUT ENOUGH FOR TEMPS TO DROP INTO THE
20S.
AS THE WRN TROUGH EDGES TO THE EAST AND A SFC-850 MB TROUGH DEVELOPS
FROM THE SRN PLAINS INTO THE UPPER MS VALLEY...WAA AND MOISTURE
ADVECTION WILL INCREASE QUICKLY BY WED AFTERNOON. THE INITIAL AREA
OF PCPN IS EXPECTED INTO THE WEST...WHERE 295K-300K ISENTROPIC LIFT
IS STRONGEST. GIVEN THE DRY ERLY FLOW AS THE HIGH GRADUALLY MOVES
EAST THROUGH NRN ONTARIO...THE SLOWER PROGRESSION OF PCPN INTO
UPPER...PER NAM...WAS PREFERRED COMPARED TO THE GFS/ECMWF. EXPECT
ENOUGH OF A LINGERING WARM LOWER LAYER FOR MOSTLY RAIN AT THE ONSET
OF MAINLY LIGHT PCPN AS AFTERNOON TEMPS CLIMB INTO THE 40F TO 45F
RANGE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
MAIN ATTENTION FOR THE LONG TERM PORTION OF THE FORECAST ARE THE
TWO WAVES OF PRECIPITATION ASSOCIATED WITH ENERGY AND LOW PRESSURE
SYSTEMS EXITING FROM THE UPPER TROUGH CURRENTLY MOVING THROUGH THE
WESTERN CONUS.
FIRST WAVE WILL BE INFLUENCING THE AREA AT THE START OF THE LONG
TERM PERIOD WILL BE ASSOCIATED WITH SHORTWAVE ENERGY EJECTING AHEAD
OF THE TROUGH EXPECTED TO BE IN THE CENTRAL ROCKIES. AT THE
SURFACE...A LOW CENTERED IN WESTERN OKLAHOMA AND THE
PANHANDLE OF TEXAS WILL BEGIN ELONGATING A TROUGH NORTHEAST INT HE
MID MISSISSIPPI VALLEY ON WEDNESDAY AFTERNOON AND THEN NORTHEAST
INTO NORTHERN LAKE MICHIGAN BY 12Z THURSDAY. WITH THE STRONG MID
LEVEL FORCING ASSOCIATED WITH 925-700MB WARM AIR ADVECTION AND
LIKELY CONVECTION ON THE EAST SIDE OF THE TROUGH...WOULD EXPECT THE
HEAVIEST PRECIPITATION TO BE JUST TO THE SOUTHEAST OF THE CWA OR
BRUSH THE SOUTHEAST PART OF THE CWA. BUT...WITH THE AREA UNDER THE
RIGHT REAR OF THE UPPER JET AND ENOUGH OVERRIDING FLOW WITH THAT
WARM AIR ADVECTION AND ISENTROPIC ASCENT ON THE 280-300K
SFCS...STILL THINK THAT THERE WILL BE ENOUGH FORCING FOR MODERATE
PRECIPITATION ACROSS MUCH OF THE CWA. GENERAL MODEL CONSENSUS OF
0.50-0.80 INCH SEEMS REASONABLE FOR MUCH OF THE AREA...WITH VALUES
APPROACHING AN INCH ALONG THE LAKE MICHIGAN SHORELINE. THIS TRICKY
PART OF THIS FORECAST IS WHAT AMOUNT OF THE PRECIP WILL FALL AS
RAIN OVER THE WESTERN HALF OF THE CWA DUE TO THE ELEVATED WARM
LAYER. THERE CONTINUES TO BE SOME DISCREPANCY IN THE AMOUNT OF WARM
AIR THAT MOVES OVER THE CENTRAL CWA AND HOW FAR WEST THAT MOVES.
THINK THE FAR WESTERN CWA WILL LIKELY SEE MAINLY SNOW /FROM
KCMX TO KIWD/...BUT COULD SEE A BRIEF PERIOD OF FREEZING RAIN
OVERNIGHT. THE AREA BETWEEN THERE AND A LINE FROM MARQUETTE TO IRON
MOUNTAIN IS THE TRICKY AREA...SINCE THERE WILL LIKELY BE ENOUGH
WARM AIR TO MELT THE SNOW ALOFT. THEN PRECIP TYPE COMES DOWN TO
SURFACE TEMPERATURES...SINCE 925MB TEMPS ARE WELL BELOW FREEZING.
WILL CONTINUE TO MENTION MAINLY FREEZING RAIN IN THAT AREA...WITH
SOME MENTION OF SNOW. ALL IN ALL...APPEARS THAT THIS WILL LIKELY BE
A SOLID ADVISORY FOR THE WESTERN HALF OF THE CWA AND THERE IS SOME
CONCERN FOR DECENT ICE ACCUMULATION DEPENDING ON WHAT THE SURFACE
TEMPS ARE. THIS ENERGY WILL SHIFT NORTHEAST ON THURSDAY MORNING AND
WITH THE 850MB FLOW BECOMING MORE SOUTHWEST...WOULD EXPECT THE
PRECIPITATION TO WEAKEN HEADING INTO THE AFTERNOON.
NEXT SYSTEM TO AFFECT THE AREA WILL BE AS THE UPPER TROUGH LIFTS TO
THE NORTHEAST AND MOVES TOWARDS THE UPPER GREAT LAKES ON THURSDAY
NIGHT INTO FRIDAY. THIS WILL INTENSIFY A LOW ALONG THE LINGERING
SURFACE TROUGH AND THEN LIKELY TRACK TOWARDS THE STRAITS OF
MACKINAC BY 12Z FRIDAY. THE MAIN CONCERN FOR WIDESPREAD
PRECIPITATION FOR THE AREA IS THE TRACK/LOCATION OF THE DRY SLOT
SURGING NORTHEAST ON THURSDAY NIGHT INTO FRIDAY. THERE ARE STILL
SOME DIFFERENCES IN THE LOW TRACK WITH THE NAM/GEM...SO OPTED TO
FOLLOW THE MORE CONSISTENT IDEA OF THE GFS/ECMWF FOR THE FORECAST.
LATEST INDICATIONS IN THE MODELS THAT THE DRY SLOT WILL AFFECT THE
CENTRAL/EASTERN CWA...BETWEEN THE DEFORMATION PRECIPITATION
AFFECTING THE WESTERN CWA AND THE CONVECTION AND HEAVY RAIN
AFFECTING LOWER MICHIGAN AHEAD OF THE COLD FRONT. THUS...WOULD
EXPECT THE HEAVIEST PRECIPITATION TO OCCUR OVER THE WESTERN THIRD OF
THE CWA THURSDAY NIGHT INTO FRIDAY...WITH THE REST OF THE AREA
SEEING LIGHTER PRECIPITATION. BASED OFF THE THERMAL PROFILE...THAT
ALSO SEEMS TO BE THE LOCATION OF THE RAIN/SNOW/MIXED PRECIPITATION
LINE...LARGELY STRETCHING FROM KIMT/KSAW. THE CONCERN FOR THE
CENTRAL CWA WILL BE THE EXPECTED AREA OF SUBFREEZING TEMPERATURES
BELOW 875MB WHICH WOULD LEAD TO THE RAIN FREEZING WHEN IT GETS TO
THE SURFACE. OUT WEST...THE PRECIPITATION WILL LIKELY START OUT AS
FREEZING RAIN AS THE WARM NOSE ROTATES THROUGH AND THEN TRANSITION
TO SNOW FROM WEST TO EAST. WHEN COMBINED WITH THE NORTHERLY FLOW OFF
LAKE SUPERIOR WITH 850MB TEMPS FALLING TO -10C ON FRIDAY SHOULD SEE
LAKE ENHANCEMENT REALLY INCREASE AMOUNTS OVER GOGEBIC/ONTONAGON
COUNTIES THROUGH THE DAY ON FRIDAY. WITH THAT AREA SEEING BOTH THE
DEFORMATION PRECIPITATION AND THE LAKE ENHANCEMENT...CURRENT
EXPECTATION WOULD BE WARNING SNOWFALL AMOUNTS AND SOME LOCATIONS
COULD SEE SOME SIGNIFICANT SNOWFALL AMOUNTS FOR MID-LATE APRIL. IN
ADDITION TO THE SNOW...STRONG NORTHERLY WINDS FROM THE KEWEENAW
THROUGH GOGEBIC COUNTY WILL LEAD TO NEAR BLIZZARD CONDITIONS EVEN
THOUGH THE SNOW WILL LIKELY BE ON THE WETTER SIDE INITIALLY.
WILL CONTINUE THE SPS FOR THE WEDNESDAY NIGHT THROUGH FRIDAY
PERIOD...SINCE I FEEL THAT ENCOMPASSES THE ENTIRE SYSTEM WELL AND
SINCE THE THE MOST SIGNIFICANT EVENT WILL BE THE SECOND SYSTEM.
COULD HAVE DONE A LONG PERIOD WATCH TO COVER BOTH EVENTS...BUT SINCE
THE FIRST WAVE SEEMS TO BE MORE OF AN ADVISORY SITUATION AND THEN A
BRIEF BREAK ON THURSDAY AFTERNOON...WASN`T SURE IF THAT WOULD COME
ACROSS WELL WITH A LONG TERM WATCH HEADLINE.
EXPECT THE LAKE ENHANCED SNOW TO CONTINUE INTO FRIDAY NIGHT BUT
WILL QUICKLY COME TO AN END ON SATURDAY AS THE UPPER TROUGH LIFTS
TO THE NORTHEAST AND SURFACE HIGH PRESSURE BUILDS OVER THE AREA.
THIS SHOULD LEAD TO A NICE BUT COOL START TO THE WEEKEND...WITH
HIGHS ONLY REACHING THE 30S IN MOST LOCATIONS. THEN AS THE HIGH AND
UPPER RIDGE SHIFTS TO THE EAST ON SUNDAY...THE NEXT WAVE FROM THE
PACIFIC NORTHWEST WILL BE APPROACHING THE AREA FOR SUNDAY NIGHT AND
CONTINUING INTO MONDAY NIGHT AND TUESDAY. THERE CONTINUES TO BE
SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND THERE ENSEMBLE
MEANS...BUT THE GENERAL IDEA OF THE UPPER TROUGH AND COLD FRONT
MOVING THROUGH THE AREA DURING THAT TIME SEEMS REASONABLE. THE AREA
WILL LIKELY SEE A BRIEF WARM UP FOR SUNDAY INTO MONDAY...BACK INTO
THE 40S...BUT THEN COOL TO BELOW NORMAL VALUES BEHIND THE COLD FRONT
ON TUESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 736 PM EDT TUE APR 16 2013
CONVERGENCE ZONE IS HELPING TO MAINTAIN MVFR CIGS AT KCMX. MODEL
GUIDANCE SUGGESTS THAT THE CONVERGENCE WILL BREAKDOWN OVER THE NEXT
COUPLE OF HRS AS WINDS GENERALLY BECOME MORE NORTHEASTERLY ACROSS
LAKE SUPERIOR. THIS SHOULD ALLOW MVFR CIGS TO SCATTER OUT BY LATE
EVENING. LATER IN THE NIGHT...BAND OF MVFR CIGS CURRENTLY N AND NE
OF THE LAKE MAY REACH KCMX. EXPECT MVFR CIGS TO SCATTER OUT EARLY IN
THE AFTN. AT KSAW...SATELLITE IMAGERY INDICATES A SUBTLE INCREASE IN
STRATOCU TO THE NW OF KSAW. WITH LOSS OF DAYTIME HEATING...THIS
STRATOCU MAY CONTINUE TO EXPAND...BRINGING POTENTIAL OF MVFR CIGS TO
KSAW BY LATE EVENING. MVFR CIGS SHOULD SCATTER OUT BY LATE WED
MORNING. AT KIWD...WITH A DOWNSLOPE COMPONENT TO DEVELOPING LIGHT
EASTERLY WIND...EXPECT VFR CONDITIONS TO PREVAIL AT KIWD. NEXT
SYSTEM MAY BRING MVFR CONDITIONS WITH -RASN TO KIWD LATE IN THE
AFTN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 436 PM EDT TUE APR 16 2013
WINDS WILL STAY BELOW 30 KNOTS THROUGH THU BEFORE INCREASING OUT OF
THE NORTH THURSDAY NIGHT INTO FRIDAY NIGHT WHEN NORTH GALES ARE
LIKELY AS A DEEP LOW PRESSURE SYSTEM MOVES TOWARD NORTHERN LAKE
MICHIGAN AND EAST UPPER MICHIGAN. THERE IS THE POTENTIAL FOR HIGHER
END GALES WITH THIS SYSTEM IN THE 40 TO 45 KNOT RANGE. THE WINDS
WILL DIMINISH FRI NIGHT INTO SAT AS THE LOW MOVES QUICKLY TO THE
NORTHEAST OF THE REGION AND HIGH PRES BUILDS IN FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
452 PM EDT MON APR 15 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 451 PM EDT MON APR 15 2013
THERE ARE A COUPLE OF PERIODS OF CONCERN IN THIS LONG TERM PERIOD.
THE FIRST WILL PUSH IN FROM THE SOUTHWEST WEDNESDAY EVENING THROUGH
THURSDAY MORNING...WITH A SECONDARY SURGE OF MOISTURE SLIDING ACROSS
UPPER MICHIGAN THURSDAY NIGHT INTO FRIDAY. LATE THIS WEEKEND INTO
EARLY NEXT WEEK MAY ALSO END UP BEING INTERESTING...WITH ANOTHER
SURGE OF WARM AIR PUSHES IN FROM THE SOUTH.
AT 00Z WEDNESDAY A WEAK SFC TROUGH MAY STILL BE OVER CENTRAL LAKE
SUPERIOR AND NORTHERN UPPER MICHIGAN...BUT THAT FEATURE SHOULD EXIT
QUICKLY AS THE LARGE AREA OF HIGH PRESSURE OVER CENTRAL CANADA
PUSHES INTO ONTARIO AND LAKE SUPERIOR OVERNIGHT. KEPT CONDITIONS DRY
FOR NOW...ALTHOUGH SOME OF THE SMALLER SCALE MODELS DID INDICATE A
FEW LIGHT FLURRIES OR SNOW SHOWERS. OTHERWISE...DRY CONDITIONS
SHOULD LINGER THROUGH WEDNESDAY MORNING...AS THE HIGH PRESSURE
SYSTEM SLOWLY EXITS TO EASTERN ONTARIO AND OVER JAMES BAY BY 00Z
THURSDAY.
WILL CONTINUE TO HEDGE THE FORECAST CLOSER TO THE ECMWF WITH THIS
PACKAGE UPDATE. ALTHOUGH IT IS A LITTLE WEAKER AND EASTWARD WITH
THE SURFACE LOW TO OUR SOUTH AND EAST DURING THE DAY THURSDAY...BOTH
THE GFS AND ECMWF HAVE THE SURFACE LOW OVER FAR EASTERN UPPER
MICHIGAN AT 18Z FRIDAY /ALTHOUGH THE GFS IS DEEPER WITH THE SYSTEM/.
PRECIPITATION TYPE AND AMOUNTS REMAIN A CONCERN...WITH RAIN MAINLY
CENTRAL AND EAST...CLOSER TO THE LOW. WEDNESDAY NIGHT STILL LOOKS
LIKE A POTENTIAL FOR FREEZING RAIN...WITH SURFACE TEMPERATURES OF
29-32F BETWEEN 01-11Z THURSDAY. WHILE THE TYPICAL ROADWAYS MAY STAY
WARM ENOUGH FOR WET CONDITIONS DUE TO LINGER SALT DEPOSITS ALREADY
ON THEM...AND BEING MORE WELL-TRAVELED. AS WE MOVE DEEPER INTO THE
SPRING SEASON IT BECOME INCREASINGLY DIFFICULT FOR ROADWAYS TO STAY
BELOW FREEZING FOR TOO LONG. STILL HAVE A GOOD CHANCE OF FREEZING
RAIN ACCUMULATING TO GENERALLY LESS THAN A TENTH OF AN INCH. KEPT
THE MENTION IN THE HWO AT THIS POINT. ALSO HAVE THE POTENTIAL FOR
2-4 INCHES OF HEAVY WET SNOW OVER THE HIGHER TERRAIN OF THE WEST
WEDNESDAY NIGHT...LINGERING INTO THURSDAY WITH A SMALL BREAK FIGURED
BEFORE WE COME UNDER THE INFLUENCE OF THE 500MB TROUGH AND COLDER
AIR PUSHING IN FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT.
NNE 850MB WINDS OF 30-50KT LOOK REALISTIC FROM 06-15Z
FRIDAY...BEFORE TURNING MORE NORTHERLY AS THE LOW PUSHES ACROSS
EASTERN UPPER MICHIGAN. INTRODUCED GALE FORCE VALUES TO PORTIONS OF
MAINLY CENTRAL LAKE SUPERIOR FRIDAY INTO FRIDAY EVENING...BUT WOULD
NOT BE SURPRISED IF WE NEED TO BUMP UP OUR FORECAST FOR THE NE WINDS
FUNNELING DOWN THE WESTERN HALF OF LAKE SUPERIOR EARLIER IN THE DAY.
THE WEST END OF THE CWA /GOGEBIC AND ONTONAGON COUNTIES/ WILL ALSO
HAVE THE BEST CHANCE OF LAKE EFFECT/LAKE ENHANCED SNOW
ACCUMULATIONS...WITH 850MB TEMPS GENERALLY COOLING BELOW -6C.
LIGHTER AMOUNTS ARE FIGURED EAST...WITH WARMER AIR WILL AROUND AND A
MIX OF RAIN OR SNOW POSSIBLE FAR EAST THROUGH THE DAY FRIDAY.
DRY WEATHER SHOULD BE THE RULE ONCE AGAIN STARTING SATURDAY AS HIGH
PRESSURE BUILDS IN AT THE SFC. HOWEVER WITH NW FLOW LINGERING ALOFT
AND N-NNW WINDS AT THE SURFACE...ALONG WITH 850MB TEMPS OF -11 TO
-14C...LINGERING SNOW SHOWERS WILL BE POSSIBLE EAST OF MARQUETTE
NEAR LAKE SUPERIOR INTO THE MID/LATE MORNING HOURS.
THERE ARE SIGNIFICANT TIMING DIFFERENCES WITH THE APPROACH OF THE
NEXT SYSTEM. THEY DO AGREE ON STRONG S WINDS AT 850MB...AGAIN
APPROACHING THE 40-55KT RANGE FROM MAINLY LATE SUNDAY AFTERNOON
THROUGH MONDAY MORNING...AS THE LLJ PUSHES W TO E ACROSS THE CWA.
THE MAIN ISSUE IS REGARDING THE TIMING OF THE NEXT SURGE OF
MOISTURE/PRECIPITATION...WHICH THE 15/12Z GFS IS MUCH MORE
PROGRESSIVE AND BRINGS IN MORNING TO THE WEST HALF. THIS IS APPROX 6
OR MORE HOURS FASTER THAN THE 15/06Z GFS RUN. THE 12Z ECMWF SHOWED A
SLOWER SOLUTION. GIVEN THE VARIABILITY SHOWN IN THE AVAILABLE
MODELS...IT SEEMS REASONABLE TO CONCENTRATE A BIT MORE ON THE NEAR
TERM...AND RUN WITH A CONTINUED CONSENSUS APPROACH AFTER 00Z MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 138 PM EDT MON APR 15 2013
ALTHOUGH MVFR CONDITIONS ARE POSSIBLE THIS AFTN AT IWD/CMX CLOSER TO
DEEPER MSTR ASSOCIATED WITH LO PRES IN MN MOVING INTO NW ONTARIO...
EXPECT PREDOMINANT VFR WX TO PREVAIL AT THE TAF SITES. DATYIME
HEATING/MIXING WL BRING GUSTY SW WINDS...WHICH WL SUBSIDE AT SUNSET
WITH SOME NOCTURNAL COOLING/STABILIZATION. APRCH OF LO PRES TROF/
SOMEWHAT DEEPER MSTR TNGT WL BRING A RETURN OF PREDOMINANT MVFR
CONDITIONS...ESPECIALLY AT CMX WITH MORE SIGNIFICANT UPSLOPE WIND
COMPONENT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EDT MON APR 15 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 459 AM EDT MON APR 15 2013
LARGER SCALE FEATURES AN UPPER TROUGH OVER UPPER LAKES EARLY THIS
WEEK WITH THE TROUGH MOVING INTO NORTHERN QUEBEC ON TUESDAY.
ASSOCIATED SURFACE LOW LIFTS TO SOUTH END OF JAMES BAY BY 12Z ON
TUESDAY AS MAIN COLD FRONT SLIDES EAST...FROM SOUTHERN QUEBEC INTO
THE MID MISSISSIPPI RIVER VALLEY.
WEAK SURFACE TROUGH MOVES ACROSS LAKE SUPERIOR AND UPPER MICHIGAN ON
TUESDAY BUT DRY AIR IN WAKE OF MAIN COLD FRONT RESULTS IN MINIMAL
CHANCES OF ANY PRECIPITATION. NORTH WIND OFF LK SUPERIOR WILL KEEP
TEMPS CHILLY AND THERE SHOULD BE BKN STRATOCU CLOUDS AROUND. QUIET
CONDITIONS STAY IN PLACE THROUGH WEDNESDAY AS HIGH PRESSURE MOVES BY
ACROSS NORTHERN ONTARIO. MID CLOUDS WILL BE ON THE INCREASE LATER
WEDNESDAY AHEAD OF DEVELOPING LOW PRESSURE SYSTEM OVER THE SOUTHERN
PLAINS. LAST 3 RUNS OF NAM HAVE TRENDED DRIER THROUGH 00Z THURSDAY.
00Z NAM HAS ONLY LGT QPF ALONG WI BORDER THROUGH 00Z THURSDAY...THEN
BRINGS HEAVIER QPF IN OVERNIGHT WEDNESDAY NIGHT. NAM SOUNDINGS SHOW
DRY LAYER FM H9-H7 LINGERING THROUGH THE DAY RESULTING IN DELAY OF
QPF INTO UPR MICHIGAN. ECMWF HAS BEEN CONSISTENT WITH HANDLING OF
THE SYSTEM AND MULTIPLE RUNS OF ECMWF SHOW QPF ARRIVING BY WEDNESDAY
AFTN...THOUGH LATEST ECMWF IS NOT AS BULLISH WITH QPF OVER FAR EAST
CWA THROUGH 00Z THURSDAY. NAM OVERALL APPEARS AT LEAST 6 HOURS
SLOWER WITH ARRIVAL OF LEAD SHORTWAVE/VORT MAX SLIDING OVER UPR
MICHIGAN/NORTHERN WI/NORTHERN LK MICHIGAN. 00Z GFS IN LINE WITH
ECMWF IDEA WITH TIMING OF SHORTWAVE AND ASSOCIATED QPF...THOUGH OVER
THE EAST IT IS ALSO A BIT SLOWER WITH ARRIVAL. SINCE THERE IS LARGE
SFC HIGH/DRY AIR FAIRLY CLOSE BY TO START DAY ON WEDNESDAY...THINK
SLOWER ARRIVAL OF QPF INTO EASTERN CWA HAS SOME MERIT. ADJUSTED
FORECAST ACCORDINGLY AND KEPT SLIGHTLY LOWER POPS INTO WEDNESDAY
EVENING OVER EAST AS WELL.
AS IT GOES WITH CURRENT SYSTEM...PTYPE WILL BE AN ISSUE WITH THIS
NEXT SYSTEM. PER FAVORED WPC/ECMWF IDEA...SFC-H85 LOW TROUGH AT
00Z THU WILL BE SET UP FROM MO INTO WESTERN WI. SFC FLOW WILL BE
FROM EAST...WHILE 925-850MB FLOW IS SE GOING TO SRLY. WARM AIR WILL
BE ON ITS WAY NORTH WEDNESDAY NIGHT AND THURSDAY. BASED ON 925-850MB
TEMPS AND 1000-850MB THICKNESSES IT APPEARS THAT FAR WEST/NORTHWEST
STAYS MAINLY IN THE FORM OF SNOW INTO THURSDAY WHILE CNTRL CWA WILL
BE MORE ON THE RAIN/SNOW EDGE. EASTERLY FLOW AT SFC AND SFC TEMPS
ONLY MARGINALLY ABOVE FREEZING ALONG WITH LIMITED WARM AIR ADVECTION
SFC-H9 POINT TO FREEZING RAIN POTENTIAL LATER WEDNESDAY NIGHT.
ALREADY MENTIONED HEAVY SNOW IN PREVIOUS HAZARDOUS WEATHER OUTLOOK.
WILL NOW ADD MENTION OF FZRA. SHOULD BE SUFFICIENTLY WARM ENOUGH FOR
JUST RAIN OVER SOUTH AND EAST CWA...THOUGH WITH INITIAL DYNAMIC
COOLING THERE MAY SOME SNOW MIXING IN WEDNESDAY EVENING OVER MUCH OF
CWA. ONLY PROBLEM IS BLYR MAY BE TOO WARM TO SUPPORT THAT AS TEMPS
ON WED AFTN MAY PUSH ABOVE 45 DEGREES BEFORE CLOUDS THICKEN. WILL
JUST USE LARGER SCALE THICKNESSES NOW AND KEEP IT ONLY RAIN FOR
SOUTH AND EAST.
GFS STARTS TO STRAY WITH HANDLING OF ENTIRE UPPER TROUGH AND SURFACE
LOWS THURSDAY NIGHT INTO FRIDAY. LAST TWO RUNS OF GFS INDICATE
STRONG SURFACE LOW DEVELOPING OVR THE CNTRL GREAT LAKES AND PRECIP
LINGERING OVER UPR MICHIGAN INTO FRIDAY NIGHT. ECMWF HAS SECONDARY
LOW PRESSURE AND MAYBE A THIRD ONE BUT IS NOT AS WRAPPED UP AS GFS.
DO THINK THERE IS NOW MORE OF A CHANCE OF SEEING LINGERING SNOW
SHOWERS DUE TO LAKE ENHANCEMENT THURSDAY NIGHT INTO FRIDAY WITH
SFC-H85 CYCLONIC FLOW AND SINCE H85 TEMPS ARE AOB -6C. TWEAKED POPS
UPWARD ON THURSDAY NIGHT...BUT THESE MAY NEED FURTHER INCREASING IF
TRENDS FROM 00Z ECMWF AND 18Z/00Z GFS CONTINUE.
ECMWF TRENDING SLOWER WITH LOW PRESSURE SYSTEM MOVING ACROSS LATE
NEXT WEEKEND. LOWERED CONSENSUS POPS TO JUST SLIGHT CHANCE FOR NEXT
SUNDAY. CONSENSUS OF MODELS KEEPS COOLER THAN AVERAGE TEMPS GOING
THROUGH NEXT WEEKEND. NO REASON TO DOUBT THIS IDEA SINCE LARGER
SCALE TROUGHING ONLY SLOWLY RELAXES THROUGH END OF EXTENDED PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 138 PM EDT MON APR 15 2013
ALTHOUGH MVFR CONDITIONS ARE POSSIBLE THIS AFTN AT IWD/CMX CLOSER TO
DEEPER MSTR ASSOCIATED WITH LO PRES IN MN MOVING INTO NW ONTARIO...
EXPECT PREDOMINANT VFR WX TO PREVAIL AT THE TAF SITES. DATYIME
HEATING/MIXING WL BRING GUSTY SW WINDS...WHICH WL SUBSIDE AT SUNSET
WITH SOME NOCTURNAL COOLING/STABILIZATION. APRCH OF LO PRES TROF/
SOMEWHAT DEEPER MSTR TNGT WL BRING A RETURN OF PREDOMINANT MVFR
CONDITIONS...ESPECIALLY AT CMX WITH MORE SIGNIFICANT UPSLOPE WIND
COMPONENT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 459 AM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
111 AM EDT MON APR 15 2013
.UPDATE...
ISSUED AT 1046 PM EDT SUN APR 14 2013
TRANSITION FROM SNOW TO SLEET/FZRA IS PROGRESSING FAIRLY CLOSE TO
EXPECTATIONS. HOWEVER...TEMPS ARE NOT RISING ACROSS UPPER MI AND
EVEN INTO NRN WI UNDER STEADY EASTERLY WINDS. AS A RESULT...FZRA IS
LIKELY TO BECOME MORE OF A PROBLEM. ON ROADWAYS THAT HAVE SEEN A
COUPLE OF INCHES OF WET/SLUSHY SNOW ACCUMULATION...FZRA MAY NOT ADD
MUCH ADDITIONAL HAZARD TO THE ALREADY VERY HAZARDOUS SLOP ON THE
ROADS. HOWEVER...ELEVATED SURFACES (CARS/TREES/POWER LINES) MAY GET
A COUPLE OF TENTHS OF ICE COATING. WITH GUSTY WINDS...WEAKENED TREE
LIMBS COULD BREAK...AND THERE MAY BE SOME POWER OUTAGES. OVER THE
FAR NW...KEWEENAW IN PARTICULAR...SNOWFALL RATES WILL LIKELY SUPPORT
ADVY HEADLINE EVEN WITHOUT THE ADDITIONAL ISSUE OF SLEET/FZRA THAT
WILL OCCUR FOR A FEW HRS LATER IN THE NIGHT. SO ADVYS HAVE BEEN
POSTED FOR DICKINSON/MARQUETTE COUNTIES WESTWARD WHERE PCPN HAS BEEN
OCCURRING THIS EVENING. ADVYS WILL EXPIRE AT 06Z EXCEPT KEWEENAW
(09Z) WITH EXPECTATION OF SFC TEMPS WARMING SUFFICIENTLY TO GET
ABOVE FREEZING. NOT MUCH PCPN HAS BEEN OCCURRING OVER THE
SCNTRL/E...BUT EXPECT A PERIOD OF RAIN TO SWEEP ACROSS THAT AREA
OVERNIGHT PER RADAR IMAGERY AND MODEL FCSTS.
&&
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 428 PM EDT SUN APR 14 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOWLY RETREATING
CLOSED LO OVER SE CANADA GIVING WAY TO SHRTWV RDGING INTO THE GREAT
LKS. WITH SFC RDG AXIS/LLVL DRY AIR SHOWN ON THE 12Z GRB RAOB UNDER
THE UPR RDGING /H925-85 DEWPTS DOWN TO -12 TO -13C/...QUIET WX IS
CURRENTLY IN PLACE OVER UPR MI. BUT MID/HI CLDS IN ADVANCE OF POTENT
NEGATIVELY TILTED SHRTWV FOLLOWING THIS RDG INTO THE NRN PLAINS ARE
SPREADING INTO THE UPR LKS. 00Z-12Z H3 HGT FALLS WERE UP TO 150M
OVER THE NRN ROCKIES/PLAINS IN ADVANCE OF THIS DISTURBANCE. LEADING
EDGE OF BAND OF WAD PCPN THAT CORRESPONDS BEST WITH SHARPER PRES
GRADIENT/ ISENTROPIC ASCENT SHOWN ON THE 290-295K ISENTROPIC SFCS
/H85-75/ IS ADVANCING NEWD THRU WI AND HAS REACHED MNM THIS AFTN.
PCPN WAS FALLING AS SN AT THE LEADING EDGE OF THIS PCPN BAND...BUT
HAS CHANGED TO FZRA/RA ON THE SRN EDGE. THE BAND IS THINNEST OVER
THE E HALF OF WI...AND PCPN HAS ENDED S OF GRB. THERE WERE ALSO
SOME TS THIS MRNG AS FAR N AS IOWA NEAR H85 WARM FNT AND AT NOSE OF
65KT H85 SW LLJ SHOWN S OF THE WARM FNT AT TOPEKA KS.
MAIN FCST CONCERNS IN THE SHORT TERM ARE PCPN TIMING/TRENDS AND
PTYPE AS WELL AS QPF.
LATE THIS AFTN...SLOWED DOWN FCST ARRIVAL OF PCPN TO ACCOUNT FOR
DRYNESS OF AIRMASS IN THE UPR GRT LKS AS WELL AS LOCATION OF BETTER
ISENTROPIC ASCENT SO FAR TO THE S. BUT ARRIVAL OF SHARPER PRES
GRADIENT/LIFT SHOWN ON THE NAM FCST 290-295K ISENTROPIC SFCS SUGGEST
PCPN WL BEGIN IN MNM COUNTY BY 21Z. FCST SDNGS/SFC OBS TO THE S SUG
BULK OF PCPN AT THE PCPN ONSET WL FALL AS SN BEFORE MIXING WITH
SLEET AND PSBLY RA OVER THE FAR S AT MNM AS ELEVATED WRMG PUSHES
TEMPS IN THE H8-75 LYR ABV ZERO. THERE COULD BE SOME SN ACCUMS UP TO
AN INCH NEAR THE WI BORDER OVER THE HIER TERRAIN W OF IMT.
TNGT...POTENT NEGATIVELY TILTED SHRTWV/SFC LO OVER SDAKOTA AT 00Z IS
FCST TO LIFT NE INTO NCENTRAL MN BY 12Z MON AND BECOME CUTOFF.
SHARPER H85-7 FGEN/MSTR CNVGC ASSOCIATED WITH H85 SE WINDS INCRSG UP
TO 50KTS BY 00Z AHEAD OF WARM FNT AS WELL AS MOST IMPRESSIVE H7 UVV
UNDER SHARPER DEEP LYR QVECTOR CNVGC OVER THE W CLOSER TO APRCHG
SHRTWV WARRANTS HIER POPS OVER THE W THIS EVNG...WITH A MORE NARROW
BAND OF LIGHTER PCPN PASSING THRU THE ERN ZNS AS SHOWN BY HIER RES
MODELS. AS THE SHRTWV SHIFTS FARTHER E AND ACCOMPANYING WARM
CONVEYOR BELT MSTR RIBBON UNDER IMPRESSIVE UPR DVGC AHEAD OF H3 JET
MAX SHIFTING ARND THE SRN FLANK OF THE CLOSED LO IN MN SHIFTS TO THE
E...HIER POPS WL ARRIVE OVER THE E AS WELL AFT 06Z AT NOSE OF
VEERING H85 WINDS TO S AND INCRSG TO 60KTS LIFTING PWAT 0.75 INCH TO
1 INCH...OR ALMOST 200 PCT OF NORMAL. THESE VIGOROUS DYNAMICS/
MOISTENING JUSTIFY QPF NEAR 1 INCH OVER THE W HALF...BUT THERE WL BE
LOWER TOTALS OVER THE E HALF BECAUSE THE WARM CONVEYOR BELT MSTR WL
MOVE STEADILY TO THE E AND LIMIT RESIDENCE TIME OF ANY HEAVIER RA.
RUNOFF FM THE HEAVY RA OVER THE W HALF IN THE PRESENCE OF LINGERING
SN PILES MAY CAUSE SOME PONDING OF WATER. MAINTAINED MENTION OF
ELEVATED TS OVER THE SE AT THE NOSE OF THIS LLJ AND WHERE H875 TEMPS
TO THE N OF SFC WARM FNT ARE PROGGED TO RISE NEAR 10C. ARRIVAL OF
VIGOROUS DRY SLOTTING IN THE JET SURGE WL DIMINISH THE PCPN LATE
TNGT SW TO NE...WITH BACK EDGE OF WARM CONVEYOR BELT MSTR NEARING
ERY-MSQ TOWARD 12Z. IN FACT...FCST SDNGS INDICATE THERE MAY BE SOME
CLRG OVER THE SW LATE WITH VIGOROUS LLVL DRYING.
MAIN FCST CONCERNS TNGT ARE FOCUSED ON PTYPE AND POTENTIAL SN/ICE
ACCUMS. WITH THE VIGOROUS WAD...FCST SDNGS SHOW EXPANDING ELEVATED
WARM LYR ARRIVING S TO N...SO SN AT ONSET OF PCPN WL CHG TO RA. BEST
CHC FOR SEVERAL INCHES OF WET SNOW WL BE OVER THE HIER TERRAIN OF
THE KEWEENAW WHERE THE WARM AIR WL ARRIVE LATEST AND TEMPS STAYED A
BIT LOWER TDAY IN THE PRESENCE OF UPSLOPE COOLING OFF THE CHILLY
WATERS OF LK SUP. THERE WL BE SOME SLEET AS WELL AS EVAPORATIVE
COOLING ASSOCIATED WITH DRY AIR SHOWN ON THE 12Z GRB RAOB MAINTAINS
SUFFICIENTLY COLD TEMPS IN THE LYR BLO THE ELEVATED WARM NOSE FOR RA
DROPS TO REFREEZE INTO ICE PELLETS. BUT AS THIS LYR SATURATES AND
WARMS...SLEET SHOULD END AND GIVE WAY TO ONLY RA AS SFC TEMPS SLOWLY
RISE THRU THE 30S. THE BIG QUESTION IS HOW LONG SFC TEMPS WL BE NEAR
32 TO ALLOW FOR FZRA. EXPLICIT MODEL FCST SNDGS HAVE INDICATED FOR
SOME TIME THAT A PERIOD OF FZRA WL OCCUR. ATLHOUGH THE TIME OF YEAR
SHOULD RULE OUT FZRA AND SFC TEMPS HAVE RISEN WELL ABV 32 AT MOST
SPOTS THIS AFTN...LINGERING LO DEWPTS/POTENTIAL FOR EVAPORATE
COOLING AS WELL AS THE FCST SDNGS INDICATE THIS THREAT MIGHT BE REAL
MAINLY OVER THE HIER TERRAIN W OF MQT-IMT. THE NAM SHOWS LINGERING
AXIS OF LOWER DEWPTS IN THE H925 LYR IN THE ELY SFC FLOW N OF WARM
FNT. OPTED TO INCLUDE A MENTION OF FZRA THIS EVNG INTO THE EARLY
OVERNGT OVER THE HIER TERRAIN OF THE NW WHERE UPSLOPE COOLING WL
KEEP TEMPS AT LEAST CLOSE TO 32 AFTER SUNSET.
CONSIDERING THE POTENTIAL FOR SOME LOCALLY HVY SN...-FZRA...AND
PONDING OF WATER ACCOMPANYING HEAVIER RA...OPTED TO ISSUE AN SPS FOR
THE W HALF OF THE CWA TO HIGHLIGHT THESE POSSIBLE HAZARDS.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 428 PM EDT SUN APR 14 2013
BY MON MORNING...THE STACKED LOW WILL BE OVER NRN MN...WITH THE
ASSOCIATED OCCLUDED FRONT NE OF THE CWA...ALLOWING THE DRY SLOT TO
QUICKLY COVER MUCH OF THE CWA BY MID MORNING. THE EXCEPTION TO THIS
WILL BE OVER THE WRN THIRD OF THE U.P. WHERE WRAP AROUND LOW LEVEL
MOISTURE WILL MOVE IN. MODELS HAVE BEEN TRENDING SLIGHTLY FARTHER E
WITH THE SFC LOW AS IT MOVES ACROSS THE MN ARROWHEAD AND FAR NRN
LAKE SUPERIOR...SO THE LOW LEVEL MOISTURE COVERAGE HAS ALSO BEEN
TRENDING FARTHER E. THE IMPACT OF THE LOW LEVEL MOISTURE WILL BE TO
ALLOW CONVECTIVE RAIN/SNOW SHOWERS DUE TO THE COLD AIR OVERHEAD IN
PROXIMITY TO THE UPPER LOW AND STEEP LOW LEVEL LAPSE RATES. WITH
MOST MODELS SHOWING A COUPLE HUNDREDTHS OF AN INCH OF QPF OVER THE
WRN THIRD OF UPPER MI...THINK CHANCE POPS FROM PREVIOUS SHIFT COVERS
IT WELL. THE GOOD LOW LEVEL MIXING WILL ALSO ALLOW FOR MIXING OF
GUSTY WINDS TO THE SFC. THINK THAT MIXING TO AROUND 800MB AS SHOWN
BY MODEL SOUNDINGS SEEMS REALISTIC...AND WITH 800MB WINDS MON OF
AROUND 45KTS...COULD SEE SOME 40-45MPH GUSTS. EVEN THOUGH THE SYSTEM
IS WEAKENING...PRESSURE RISE/FALL COUPLET ORIENTATION WILL ENHANCE
THE GEOSTROPHIC WIND COMPONENT. DO NOT THINK CONDITIONS WARRANT WIND
ADVISORY...BUT WILL BE BORDERLINE. ANOTHER FACTOR WITH THE GOOD
MIXING IS THAT SFC TEMPS WILL BE ABLE TO WARM CONSIDERABLY...AND
SHOULD REACH AT LEAST 40 EVERYWHERE...BUT IN AREAS THAT DO NOT SEE
THE LOW LEVEL MOISTURE /SCENTRAL AND ERN U.P./ WILL GET UP TO AROUND
50. COULD SEE SOME LAKE EFFECT SNOW OVER THE FAR W ALONG AND BEHIND
THE SECONDARY COLD FRONT AS WINDS TURN NWLY...BUT COVERAGE SHOULD BE
LIMITED AT BEST.
RIDGING BUILD IN ON TUE AND TUE NIGHT...SO WILL SEE QUIET WEATHER.
GFS CONTINUES TO SHOW SOME QPF OVER THE WRN HALF OF UPPER MI
TUE...BUT GIVEN DOWNWARD MOTION WILL KEEP THE FORECAST DRY.
WED NIGHT AND THURSDAY...ATTENTION THEN TURNS TO A DEEP UPPER TROUGH
THAT WILL TRAVERSE THE MID SECTION OF THE COUNTRY FROM MID TO LATE
WEEK. THIS TROUGH RESULTS IN A SFC LOW MOVING THROUGH THE
REGION...ALTHOUGH THE EXACT TRACK REMAINS UNCERTAIN. DEFINITELY
FAVOR THE TRACK GIVEN BY THE ECMWF WHICH HAS MUCH BETTER CONTINUITY
IN BRINGING THE SFC LOW FROM NRN IL AT 06Z THU TO NEAR TRAVERSE CITY
MI BY 12Z THU THEN TO LAKE HURON BY 18Z THU. THE ECMWF HAS BEEN
TRENDING EVER SO SLIGHTLY WESTWARD WITH THE LOW TRACK...BUT NOT
NEARLY AS MUCH AS THE GFS AND GEM WHICH HAVE SHOWN POOR RUN TO RUN
CONTINUITY AND NOW WITH THE LATEST RUNS ARE CLOSER TO THE ECMWF
SOLUTION. WITH THE ECMWF SOLUTION...AREAS NEAR LAKE MI AND OVER THE
ERN CWA WOULD BE FAVORED FOR MOSTLY RAIN...WITH THE DRY SLOT MOVING
IN BEFORE THE COLDER AIR CAN TURN THINGS TO SNOW. IN NCENTRAL AND
WRN UPPER MI...TEMPERATURES AND LOW TRACK WILL BE FAVORABLE FOR
HEAVY SNOW. IT IS IMPORTANT TO EMPHASIZE THAT THERE IS CONSIDERABLE
UNCERTAINTY WITH THE TRACK OF THIS SYSTEM...WITH A WIDE RANGE OF
PRECIPITATION POSSIBILITIES DEPENDING ON THE TRACK...RANGING FROM HEAVY
SNOW TO MOSTLY RAIN AND WARMER TEMPERATURES OVER THE DEEP SNOWPACK
ACROSS THE AREA. WHATEVER SCENARIO PLAYS OUT...IT BEARS CLOSELY
WATCHING THIS SYSTEM OVER THE NEXT FEW DAYS. WILL CONTINUE TO
MENTION THE POTENTIAL FOR HEAVY SNOW IN THE HAZARDOUS WEATHER
OUTLOOK.
REGARDLESS OF THE EXACT TRACK...850MB TEMPS DROP TO -10 TO -14C PER
THE GFS AND ECMWF BY 18Z FRI WHICH COMBINED WITH THE UPPER TROUGH AND
N-NW FLOW SHOULD BE ENOUGH FOR AT LEAST SOME LAKE ENHANCED SNOW
FRIDAY INTO SATURDAY MORNING. THIS WILL ALSO ALLOW FOR TEMPS TO BE
WELL BELOW NORMAL ONCE AGAIN WITH TEMPS LIKELY STRUGGLING TO REACH
THE MID 30S SATURDAY. LOTS OF UNCERTAINTY NEXT SUN GIVEN MODEL
DISAGREEMENT AND RUN TO RUN DISCONTINUITY...SO WILL JUST USE A
CONSENSUS OF GUIDANCE AND FOCUS ON SHORTER TERM ISSUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 111 AM EDT MON APR 15 2013
PCPN ASSOCIATED WITH LOW PRES TRACKING NE THRU MN WILL END FROM SW
TO NE LATE IN THE NIGHT. WHILE TEMPS HAVE WARMED ENOUGH FOR PTYPE
TO BE JUST -RA AT KIWD/KSAW...KCMX MAY SEE ANOTHER COUPLE OF HRS OF
FZRASNPL BEFORE IT CHANGES TO RA. DOWNSLOPING E/SE WIND SHOULD HELP
KEEP CONDITIONS NO LWR THAN MVFR AT KIWD. MEANWHILE...UPSLOPE E TO
SE WINDS WILL LIKELY RESULT IN LIFR CONDITIONS CONTINUING AT KCMX
AND LATER AT KSAW. ALTHOUGH LOW-LEVEL JET OF 50-60KT AT 2-5KFT WILL
BE SHIFTING ACROSS THE AREA OVERNIGHT...DID NOT INCLUDE LLWS SINCE
GUSTY SFC WINDS ARE EXPECTED. DRY SLOT WORKING THRU THE AREA IN THE
MORNING SHOULD BRING RAPID IMPROVEMENT TO VFR AT ALL 3 SITES WITH
CLOUDS LIKELY SCATTERING OUT FOR A TIME. THEN...MOISTURE WRAPPING
AROUND SFC LOW LIFTING THRU NRN MN INTO ONTARIO WILL PROBABLY BRING
MVFR CIGS BACK TO KIWD/KCMX DURING THE DAY TODAY. MIGHT BE A FEW
-SHRASN AS WELL...BUT CONFIDENCE IS LOW AND SO NOT WORTH A MENTION
AT THIS TIME. GUSTY SW WINDS ARE EXPECTED TODAY AS THE SFC LOW LIFTS
BY TO THE NW OF THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EDT SUN APR 14 2013
EXPECT ENE WINDS TO 25 TO 30 KTS TO INCREASE TO GALES TO 35 KTS OVER
MUCH OF THE LAKE TONIGHT AND VEER SE AS VIGOROUS LO PRES NOW IN THE
NORTHERN PLAINS MOVES THRU MINNESOTA AND THE PRES GRADIENT TIGHTENS
SHARPLY. THE STRONGEST WINDS WL OCCUR IN AREAS WHERE TOPOGRAPHY
ENHANCES THE E TO SE WINDS. LATER TONIGHT...WINDS OVER THE W HALF
WILL DIMINISH WITH THE CLOSER APPROACH OF THE LOW AND A WEAKER PRES
GRADIENT. MAINTAINED GALE WARNINGS ISSUED EARLIER FOR LATE TODAY
THRU TONIGHT.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE
AGAIN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
MIZ001-003.
FREEZING RAIN ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
MIZ010-011.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT /1 AM CDT/ EARLY THIS
MORNING FOR MIZ002-004-005-009-084.
LAKE SUPERIOR...
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ266-267.
GALE WARNING UNTIL 4 AM EDT /3 AM CDT/ EARLY THIS MORNING FOR
LSZ162-263.
GALE WARNING UNTIL 5 AM EDT EARLY THIS MORNING FOR LSZ244>246-
264-265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...07
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
1243 AM CDT MON APR 15 2013
.AVIATION.../06Z TAF ISSUANCE/
WITH THE DRY SLOT MOVING THROUGH THE FA...THERE WILL BE A MIX OF
PTYPES INCLUDING SNOW/FZRA/DZ/BR/FG AND BLSN. CIGS/VSBYS WILL RUN
THE GAMUT FROM MVFR/IFR/LIFR AND BACK. THE SFC LOW WILL MOVE
NEARBY AND THE GUSTY SFC WINDS WILL SUBSIDE BEFORE INCREASING
AGAIN BY 15Z OUT OF THE WEST.
&&
.PREV DISCUSSION... /ISSUED 941 PM CDT SUN APR 14 2013/
UPDATE...DRY SLOT IS BEGINNING TO WORK ITS WAY INTO THE SW
PORTION OF THE FA PER SATELLITE IMAGERY. MOISTURE FROM THE GULF
CONTINUES TO ADVECT INTO MUCH OF THE FA WHICH HAS LED TO THE PCPN
IN NW WI CHANGING OVER TO RAIN. HOWEVER...SFC TEMPS ARE HOVERING
AROUND 32F SO WILL PERSIST IN MONITORING FOR ADDITIONAL FZRA. SFC
OBS INDICATE THE FZRA HAS ENDED IN NW WI FOR NOW. EXPECT THE DRY
SLOT TO REACH THE TWIN PORTS AROUND 530Z. THIS WILL BRING THE
GUSTY WINDS TO AN END AS SEEN IN OBS DOWNSTREAM WHERE DRY SLOT HAS
ALREADY PASSED. MADE SOME MINOR ADJUSTMENTS TO THE WIND AS A
RESULT. REST OF THE FORECAST IN THE BALLPARK INCLUDING HEADLINES.
PREV DISCUSSION... /ISSUED 730 PM CDT SUN APR 14 2013/
UPDATE...ADDED FZRA TO NW WI AS FZRA HAS BEEN REPORTED AT
HYR AND SHELL LAKE. BAND OF HIGHER REFLECTIVITIES CURRENTLY ON
RADAR HAS BEEN MOSTLY FZRA...BUT REPORTS ARE BEGINNING TO INDICATE
IT IS CHANGING OVER TO RAIN. HAVE EXTENDED THE WINTER WEATHER
ADVISORIES IN MUCH OF NORTHWEST WI THAT WERE DUE TO EXPIRE AT 00Z
TO 06Z. THIS IS TO ACCOUNT FOR THE FZRA AND THE CONTINUED WINTRY
MIX THIS EVENING. NO OTHER BIG CHANGES.
AVIATION...00Z TAFS.
A WINTRY MIXED BAG OF PCPN TYPES ARE FORECAST AS THE SFC LOW MOVES
INTO SOUTHERN MN. CIGS AND VSBYS WILL VARY WILDLY FROM MVFR TO IFR
TO LIFR AND BACK AGAIN. SNOW WILL BE THE PREDOMINATE PTYPE FROM
BRD TO HIB AND INL WITH SNOW/SLEET AT DLH AND SNOW/FZRA/SLEET/RAIN
AFFECTING HYR. THIS WILL PERSIST THROUGH THE FORECAST. GUSTY SFC
WINDS WILL PREVAIL THROUGH THE FORECAST AS WELL.
PREV DISCUSSION... /ISSUED 308 PM CDT SUN APR 14 2013/
SHORT TERM.../NOW - MONDAY/
THE FOCUS REMAINS THE WINTRY STORM SYSTEM THAT IS BEGINNING TO
MOVE INTO THE SOUTHERN FORECAST AREA. OVERALL...THIS SYSTEM HAS
BEEN DIFFICULT TO FORECAST FOR DUE TO DELAYS IN WHICH THE PCPN
FORMS AND MOVES INTO THE FORECAST AREA...CONSIDERABLE MODEL
DIFFERENCES IN SNOWFALL AMOUNTS...AND PCPN TYPE ISSUES FOR
NW WISCONSIN AND EAST CENTRAL MINNESOTA. THROUGH THE COURSE OF
THIS SHIFT...I HAVE ATTEMPTED TO DELAY THE ONSET OF THE PCPN AND
COMMUNICATE THE DELAY VIA THE GRAPHIC WEATHER STORY AND ON
FACEBOOK. THE MODELS SUGGEST THAT THE PCPN WILL INCREASE IN ITS
NORTHWARD SPEED LATER THIS AFTERNOON...SO I THINK WE MAY HAVE
FINALLY GOTTEN CLOSER TO BETTER DETERMINING TIMING. I EXTENDED
SOME ADVISORIES INTO EARLY THIS EVENING BASED ON THE PCPN DELAY
AND TO ALLOW THE EVENING SHIFT FORECASTER TIME TO SEE HOW THINGS
PAN OUT. I ALSO NOW THINK SOME AREAS OF NORTHERN MINNESOTA COULD
GET ANOTHER INCH OR TWO OF MORE SNOW THAN PREVIOUSLY
THOUGHT...SUCH AS ALONG THE NORTH SHORE.
THROUGH TONIGHT...A POTENT MID/UPPER LEVEL LOW IN THE NORTHERN
HIGH PLAINS AND ITS ASSOCIATED SURFACE LOW IN THE CENTRAL PLAINS
(EASTERN NEBRASKA AND WESTERN IOWA) WILL LIFT INTO MINNESOTA
TONIGHT. THE PCPN EXPECTED WITH THIS SYSTEM IS MOVING NORTHWARD
FROM EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN AND ALREADY
BEGINNING TO MOVE INTO NORTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. THE PCPN IS EXPECTED TO SPREAD ACROSS THE REST OF THE
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN THROUGH THE REST OF
THE AFTERNOON AND INTO THIS EVENING. THE MODELS SUGGEST THE
INITIAL BAND OF PCPN WILL COME DOWN AS SNOW AND MAY COME DOWN
QUITE FAST...WITH LIKELY SNOW RATES OF UP TO 1 TO 2 INCHES PER
HOUR IF NOT MORE. RECENT HRRR MODEL RUNS HAVE SHOWN SOME PERIODS
LATER THIS AFTERNOON OF 2 TO 3 INCHES PER HOUR. THERE IS STRONG
FRONTOGENESIS WITH THIS INITIAL BAND...SO IT IS CERTAINLY
POSSIBLE. CONSIDERING THE RELATIVELY WARM TEMPERATURES ACROSS THE
FORECAST AREA...MID 30S TO LOW 40S...THE PCPN MAY BRIEFLY BEGIN AS
A LIGHT RAIN BEFORE SWITCHING OVER TO SNOW ONCE THE RATES INCREASE
AND THE COLUMN COOLS. THERE WILL ALSO LIKELY BE A TRANSITION TO
SLEET AND RAIN ACROSS MUCH OF NORTHWEST WISCONSIN LATE THIS
AFTERNOON AND THIS EVENING. MUCH OF NORTHEAST MINNESOTA SHOULD GET
ABOUT 4 TO 9 INCHES OF SNOW...WITH THE GREATEST TOTALS ACROSS FAR
NORTHERN MINNESOTA. SOME AREAS MAY GET UP TO 10 INCHES...SUCH AS
ALONG THE NORTH SHORE OF LAKE SUPERIOR. I EXPECT LESS AMOUNTS OF
SNOW ACROSS NORTHWEST WISCONSIN AND EAST CENTRAL MINNESOTA BECAUSE
OF THE SLEET AND RAIN. HOWEVER...I WOULD NOT BE SURPRISED IF SOME
AREAS SEE CONSIDERABLE ACCUMULATION OF SLEET...WHICH IS WHY I
INCLUDED THE ACCUMULATION IN THE SNOW TOTALS I PROVIDED IN THE
WINTER WEATHER ADVISORIES FOR NORTHWEST WISCONSIN. STRONG EAST
WINDS ARE DEVELOPING ACROSS THE FORECAST AREA THIS AFTERNOON...AND
THEY SHOULD CONTINUE TO STRENGTHEN INTO THIS EVENING. THE WINDS
WILL BE STRONGEST NEAR LAKE SUPERIOR...ESPECIALLY NEAR THE TWIN
PORTS. THE 15 TO 30 MPH WINDS WITH GUSTS UP TO 40 MPH NEAR LAKE
SUPERIOR COULD REALLY REDUCE VISIBILITY DURING THE HEAVIER SNOW
BANDS AND CAUSE BRIEF NEAR WHITE-OUT CONDITIONS.
MONDAY...THE SNOW WILL LIKELY CONTINUE ACROSS MOST OF THE FORECAST
AREA THROUGH AT LEAST THE EARLY AFTERNOON AS THE LOW LIFTS INTO
ONTARIO. UP TO ADDITIONAL 1 TO 3 INCHES OF SNOW COULD FALL ACROSS
THE NORTHERN FORECAST AREA DURING THE DAY. THE WINTER STORM
WARNING FOR THE NORTHERN FORECAST AREA RUNS THROUGH 15Z TOMORROW
MORNING...BUT WE MIGHT NEED TO EXTEND THE WARNING INTO SUNDAY
AFTERNOON IF THE SNOW AND REDUCED VISIBILITY ARE STILL LINGERING.
GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP IN THE WAKE OF THE
PASSING LOW PRESSURE SYSTEM. TEMPERATURES SHOULD BE IN THE UPPER
30S TO LOW 40S.
LONG TERM.../MONDAY NIGHT - SATURDAY/
THE UPPER LOW WILL BE OVER THE NORTHERN MINNESOTA/NORTHERN LAKE
SUPERIOR AREA 00Z TUESDAY THEN CONTINUE E/NE MONDAY NIGHT. A BAGGY
UPPER TROUGH...WITH AN EXTENSION TO THE SURFACE WILL REMAIN OVER
THE CWA INTO MONDAY NIGHT. WE KEPT A CHANCE FOR SNOW OVER MUCH OF
OUR NORTHEAST MINNESOTA ZONES MONDAY NIGHT...WITH THE BEST CHANCE
OVER THE BORDER REGION.
AN UPPER RIDGE WILL BUILD OVER THE REGION BRIEFLY TUESDAY...WITH
MOST AREAS DRY INTO TUESDAY NIGHT.
A DEEP TROUGH WILL THEN MOVE OVER THE ROCKIES TUESDAY
NIGHT...MOVING SLOWLY EAST THROUGH THE WEEK AFFECTING THE
NORTHLAND. ANOTHER SPRING STORM IS POISED TO AFFECT THE NORTHLAND
WEDNESDAY INTO AT LEAST THURSDAY...POSSIBLY LINGERING A BIT
LONGER. BOTH THE GFS AND ECMWF ARE IN GENERAL AGREEMENT WITH THE
TRACK OF THE SURFACE LOW...TAKING IT FROM THE TEXAS PANHANDLE AT
12Z WEDNESDAY TO LAKE MICHIGAN/SOUTHEAST WISCONSIN BY 12Z
THURSDAY...THEN IT CONTINUES NORTHEAST. AS IS THE CASE WITH THESE
SPRING STORMS...THE THERMAL PROFILES WILL BE CRITICAL TO PRECIP
TYPE. IT DOES APPEAR TEMPERATURES WILL BE WARM ENOUGH FOR A MIX
OVER AT LEAST NORTHWEST WISCONSIN. WE HAVE A RAIN/SNOW MIX OVER
NORTHWEST WISCONSIN WEDNESDAY NIGHT/THURSDAY...AND WILL LIKELY
NEED TO ADJUST THAT AS THIS SYSTEM NEARS. THE THREAT FOR MORE
ACCUMULATING SNOW IS INCREASING OVER NORTHEAST MINNESOTA INTO FAR
NORTHWEST WISCONSIN WEDNESDAY INTO THURSDAY. IT`S VERY DIFFICULT
TO TRY AND PLACE A NUMBER ON SNOW ACCUMULATION AT THIS POINT WITH
SO MUCH UNCERTAINTY REVOLVING THE PRECIP TYPE...BUT AT LEAST
SEVERAL INCHES OF SNOW WILL FALL OVER EASTERN MINNESOTA/FAR
NORTHWEST WISCONSIN FROM THIS SYSTEM. THE FORECAST MID-LATE WEEK
IS WORTH MONITORING CLOSELY AS THE PROBABILITY IT WILL HAVE A
SIGNIFICANT IMPACT ON THE NORTHLAND/S WEATHER IS INCREASING. MORE
DETAIL REGARDING PRECIP TYPE/AMOUNTS WILL BE ADDED AS WE PROGRESS
INTO THE EARLY PART OF THE WEEK.
AS THE UPPER TROUGH PASSES LATE IN THE WEEK...A SURFACE HIGH WILL
MOVE OVER THE AREA DRYING THINGS OUT FOR A TIME LATE IN THE
WEEK/EARLY WEEKEND. ANOTHER SHORTWAVE WILL BRING ANOTHER CHANCE
FOR MIXED PRECIP SATURDAY NIGHT/SUNDAY BUT THIS SYSTEM DOES NOT
LOOK TO BE PARTICULARLY STRONG.
TEMPERATURES THROUGH MOST OF THE PERIOD WILL REMAIN BELOW NORMAL.
AVIATION.../18Z TAFS/
AREA RADARS SHOWED PRECIPITATION WAS MOVING NORTH THROUGH
MINNESOTA/WISCONSIN...AND WAS BECOMING MORE WIDESPREAD. THE NAM
HAS A PRETTY GOOD HANDLE ON THIS...AS DO THE HIGH RES MODELS. WE
EXPECT THE PRECIPITATION TO BEGIN AS SNOW ALL AREAS...THEN IT MAY
BECOME A WINTRY MIX AT KHYR...AND POSSIBLY AT KBRD BRIEFLY. TIMING
IN THE TAFS MAY NEED TO BE ADJUSTED BY AN HOUR OR SO...AND WE`LL
DO THAT AS CONFIDENCE INCREASES FOR AN EXACT STARTING TIME.
VSBYS WILL DROP TO IFR OR LIFR WITHIN AN HOUR OF PRECIP
ONSET...AND AREAS AROUND LAKE SUPERIOR WILL SEE WINDY CONDITIONS
FURTHER REDUCING THE VSBY IN BLOWING SNOW. A DRY SLOT WILL WORK
NORTH LATER THIS EVENING/TONIGHT AND CAUSE THE PRECIP TO DIMINISH
OVER MOST OF THE TAFS. FORECAST SOUNDINGS SHOW TOP DOWN
DRYING...SO SOME SPOTTY DRIZZLE OR FREEZING DRIZZLE IS NOT OUT OF
THE QUESTION. WE DID NOT ADD THAT TO THE TAFS AT THIS TIME...AS
THAT IS MORE OF A SHORT TERM FORECAST ISSUE AND CAN BE ADDRESSED
WITH LATER UPDATES.
WINDS WILL SWITCH FROM EASTERLY TO SOUTHERLY LAT TONIGHT/MONDAY
MORNING...THEN BECOME SOUTHWEST.
&&
.POINT TEMPS/POPS...
DLH 30 38 26 34 / 20 10 10 50
INL 26 36 24 37 / 50 20 10 40
BRD 29 38 28 38 / 10 10 10 60
HYR 30 42 27 41 / 10 10 10 60
ASX 31 41 27 37 / 10 10 10 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT THIS MORNING FOR MNZ025-026-
033>035-037.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
MNZ036-038.
WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ010>012-
018>021.
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT EARLY THIS MORNING FOR
WIZ003-004-006>009.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT THIS MORNING FOR WIZ001-
002.
LS...GALE WARNING UNTIL 3 AM CDT EARLY THIS MORNING FOR LSZ121-
140>148.
&&
$$
SHORT TERM...CANNON
LONG TERM....DAP
AVIATION...DAP
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
952 PM CDT TUE APR 16 2013
.UPDATE...
ISSUED AT 951 PM CDT TUE APR 16 2013
FORECAST UPDATED TO ACCOUNT FOR HOURLY TRENDS PERTAINING TO THE
PESKY FRONT THAT IS LINGERING ABOUT THE AREA. THERE CONTINUES TO
BE A SIGNIFICANT TEMPERATURE AND MOISTURE DIFFERENCE ACROSS THE
BOUNDARY AND FURTHER REFINEMENTS ARE LIKELY AS THE NIGHT PROGRESSES.
OBSERVATIONS FROM THIS EVENING SUGGEST THAT MUCH OF THE REGION
WILL REMAIN CAPPED INTO THE OVERNIGHT HOURS. PAST FEW VERSIONS OF
THE RAP WEAKEN THE CAP OF AN ELEVATED PARCEL (AROUND 875 TO 850
MB) IN THE 08Z TO 10Z RANGE ACROSS FAR NORTHWEST PORTIONS OF THE
OUTLOOK AREA. EVEN STILL...THE 850MB FRONT APPEARS TO BE SETTING
UP ACROSS NORTHERN PORTIONS OF KS/MO. WILL NEED TO MONITOR ANY
CONVECTION DEVELOPING IN CENTRAL/WESTERN KANSAS AND THIS MAY CLIP
AREA ALONG/NORTHWEST OF A LINE FROM PITTSBURG KS TO THE LAKE OF
THE OZARKS REGION. PREVIOUS FORECAST UPDATE SHUNTED POPS TO THIS
AREA AND WILL TWEAK AS NECESSARY. WITH AROUND 1500 J/KG OF MUCAPE
POSSIBLE OVERNIGHT...ANY STORMS THAT ARE ABLE TO DEVELOP/MOVE INTO
THE AREA (WHICH WOULD BE ELEVATED IN NATURE) COULD POSE A
MARGINALLY SEVERE HAIL RISK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 644 PM CDT TUE APR 16 2013
A PRETTY INCREDIBLE TEMPERATURE GRADIENT EXISTED OVER THE OZARKS
THIS EVENING...AS A STALLED OUT FRONTAL SYSTEM WAS POSITIONED FROM
TABLE ROCK LAKE UP TO WINONA.
IN CENTRAL MISSOURI...TEMPERATURES WERE IN THE 40S...WHILE MIDDLE
70S WERE COMMON IN PLACES NEAR THE ARKANSAS STATE LINE.
WE MADE SOME ADJUSTMENTS REGARDING PRECIPITATION CHANCES. WE TOOK
OUT POPS FOR LOCATIONS SOUTH OF THE WARM FRONT...AS THIS AIRMASS
REMAINS INHIBITED. WITH NO FORCING MECHANISM TO TRIGGER CONVECTION
WITHIN THE WARM SECTOR...THESE AREAS SHOULD REMAIN DRY THROUGH
TONIGHT.
SHOWERS AND MAYBE A FEW THUNDERSTORMS ARE POSSIBLE NORTH OF
INTERSTATE 44 CORRIDOR. LAST NIGHT...THE CONVECTION WAS POSITIONED
CLOSELY WITH THE 850MB FRONT...WHICH IS UP ACROSS WEST CENTRAL AND
CENTRAL MISSOURI TONIGHT. THESE LOCATIONS WILL EXPERIENCE THE
BETTER CHANCES FOR RAIN...OTHERWISE...MOST LOCATIONS WILL REMAIN
DRY TONIGHT.
THE FRONT SHOULD BEGIN TO LIFT NORTHWARD THROUGH THE WEDNESDAY
MORNING HOURS. THIS WILL CAUSE TEMPERATURES ACROSS MOST OF THE CWA
TO WARM INTO THE 70S AND 80S.
THUNDERSTORMS WILL BE POSSIBLE...PARTICULARLY DURING THE AFTERNOON
AND EVENING HOURS...WITH SOME OF THE THESE STORMS BECOMING SEVERE.
CRAMER
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 228 PM CDT TUE APR 16 2013
THE CONVECTION WILL LIKELY FORM INTO A LINEAR MCS DURING THE
EVENING WITH THE MAIN RISK SHIFTING TO STRAIGHT LINE WIND DAMAGE.
HOWEVER WITH STRONG LOW LEVEL SHEAR PERSISTING THROUGH THE
NIGHT...CAN NOT RULE OUT A FEW QLCS TORNADOES WITHIN THE LINE. THE
FRONT (SIMILAR TO LAST WEEKS SYSTEM) WILL ONLY SLOWLY MAKE
PROGRESS INTO THE CWA BY THURSDAY MORNING WITH THE UPPER LEVEL JET
STREAK LIKELY AIDING IN DEVELOPING LOW PRESSURE ALONG THE FRONTAL
BOUNDARY THROUGH THE MORNING HOURS THURSDAY. THE EASTERN OZARKS
WILL LIKELY HAVE THE BEST CHANCE OF SEEING REDEVELOPMENT OF SEVERE
STORMS DURING THE AFTERNOON/EVENING ON THURSDAY BEFORE THE FRONT
PUSHES EAST OF THE AREA.
COLDER AIR WILL PUSH IN (LIKE LAST WEEK) BEHIND THE FRONT WITH
TEMPERATURES DROPPING INTO THE LOW TO MID 30S OVER THE WESTERN CWA
THURSDAY NIGHT AND MUCH OF THE AREA FRIDAY NIGHT. WILL NEED TO
MONITOR FOR POTENTIAL OF FROST/FREEZE HEADLINES.
SHOULD SEE A MODERATING TEMPERATURE TREND OVER THE WEEKEND WITH
GENERALLY DRY CONDITIONS...HOWEVER UNSETTLED CONDITIONS APPEAR
LIKELY FOR THE FIRST HALF OF NEXT WEEK AS AN UPPER LEVEL TROUGH
BEGINS TO DEVELOP IN THE CENTRAL U.S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 644 PM CDT TUE APR 16 2013
PILOTS FLYING IN AND OUT OF THE SOUTHWEST MISSOURI AIRPORTS CAN
EXPECT VFR CONDITIONS THROUGH THE EVENING HOURS.
HOWEVER...LOWER FLIGHT CONDITIONS WILL BE POSSIBLE AFTER MIDNIGHT
TONIGHT.
LOW CLOUDS AND LIGHT FOG ARE EXPECTED...AS A WARM FRONT LIFTS
THROUGH THE REGION EARLY WEDNESDAY MORNING.
AS THIS FRONT SURGES NORTHWARD...SURFACE WINDS WILL SHIFT TO THE
SOUTHEAST.
PILOTS WILL ALSO NEED TO MONITOR RADAR TRENDS CLOSELY TOMORROW AS
STRONG TO SEVERE STORMS WILL BE POSSIBLE ACROSS THE OZARKS. SAFE TRAVELS.
CRAMER
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY
NIGHT FOR MOZ055>058-066>071-077>081-088>091-093-094-101-
102.
KS...FLASH FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY
NIGHT FOR KSZ073-097-101.
&&
$$
UPDATE...GAGAN
SHORT TERM...CRAMER
LONG TERM...LINDENBERG
AVIATION...CRAMER
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
843 PM CDT Tue Apr 16 2013
.UPDATE...
Issued at 840 PM CDT TUE APR 16 2013
00Z raobs from surrounding sites as well as sites to the south reveal
a very stout elevated mixed layer (EML) that will be difficult to
overcome. Lack of radar returns within a 300 mile radius confirms
this. Have already lowered evening PoPs as a result and am
considering lowering them after midnight as well. Thinking scattered
coverage vs widespread as current PoPs would indicate. Would like to
get a look at the 00Z NAM before committing to lowering the PoPs. Do
believe the 00z RAP looks reasonable with best chances for convection
over the northern /12 of CWA where cap should be weaker.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 425 PM CDT TUE APR 16 2013
Current water vapor imagery and H5 heights indicate a vigorous
trough moving from eastern Ontario into Quebec with associated cold
front draped across the eastern Great Lakes region and into the Ohio
River Valley. Southwest flow aloft will continue over the central
portion of the country as an upper level ridge strengthens in
response to a relatively broad trough continuing to dig into the
inter-mountain west and Great Basin. At the surface...stationary/warm
front extends from central Texas to south-central Oklahoma and on up
into northwest Arkansas and southeast Missouri. Temperatures in the
upper 70s to low 80s made for a nice afternoon south of the this
front with temperatures in the 40s and 50s just north of the frontal
boundary.
Current elevated front will be the focus for convection tonight and
through tomorrow night. Upper level diffluence will increase as the
western trough digs into the Great Basin. With moisture continuing to
pool along and south of the warm front, and steepening lapse rates,
expect elevated scattered thunderstorms to develop near the front
late this evening. Much of the overnight activity will remain along
the 700mb thermal ridge as low-level jet increases across the south-
central plains. Primary severe threat looks to be large hail overnight
tonight and early tomorrow morning as instability increases and bulk
shear values increase to near 50kts. Both the GFS and EC have at
least 500 J/kg of CAPE across much of the CWA and increasing to
around 1500 J/kg by tomorrow afternoon.
Thunderstorm coverage will increase through tomorrow morning and
another chance for severe weather by tomorrow afternoon and evening.
Given decent moisture profiles and the chance for heavy rainfall in
many locations, have decided to issue a flash flood watch
encompassing the entire CWA. The flash flood watch will extend from
noon tomorrow through Thursday. Felt that the main threat would not
be recognized until tomorrow, especially north of I-70 where flash
flood guidance has suggested that higher rainfall amounts will be
needed to achieve saturation and then runoff. Storm relative flow
aligned generally parallel to the surface front will allow for
training of thunderstorm and areas receiving excessive rainfall
amounts.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 425 PM CDT TUE APR 16 2013
Wednesday Night...severe weather may be ongoing as we transit into
the evening and overnight hours of Wednesday. Warm sector showers
and thunderstorm activity will last into the evening hours of
Wednesday before a cold front sweeps from west to east across the
forecast region early late Wednesday night through the afternoon
hours of Thursday. There will be a ongoing threat of severe weather,
though as the evening progresses the instability fueling the
potentially severe storms will be waining taking the threat for
severe weather with it. However, the potential for large hail,
damaging winds and isolated tornadoes will persist into the early
evening hours of Wednesday. As the front moves through the threat
will transit to hail and damaging winds for the late night hours,
though with precipitable water values of 1.5 inches expected and
winds running parallel to the advancing cold front, heavy rain and
flooding will be a persistent concern.
Thursday...severe weather threat should come to an end by the early
morning hours, if the waining instability hasn`t already brought the
threat to an end Wednesday night. However, rain on the backside of
the front may persist long enough to exacerbate the already wet
conditions, which could keep the flooding threat going through much
of the daylight hours. Will leave it to later shifts to perhaps
cancel the Flash Flood Watch early if need be. Otherwise, with the
cold air on the back side of this system, have included a brief
mention of rain and snow early Friday morning, though no
accumulations are expected even if it where all snow.
With the cold temperatures once again sweeping across the region
behind the cold front, expect readings to be suppressed below normal
through the weekend and into next work week, when another reinforcing
shot of cold air will sweep into the Plains States...again.
Otherwise, a shortwave trough in the northwest flow late in the
weekend may bring more showers back to the region, first as it lifts
a modest warm front into Iowa Sunday, before the reinforcing shot of
cold air arrives possibly Monday or Tuesday. This will keep the
threat of rain across the region from Sunday afternoon through
Tuesday, with below normal temperatures.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 640 PM CDT TUE APR 16 2013
MVFR ceilings now over west central MO will gradually spread north
this evening. Still anticipating the low level jet to initiate
widespread elevated convection over KS and spread quickly northeast.
While convection will affect all 3 terminals during this 24-hour
period timing of thunder is questionable. Believe initial activity
arriving after midnight can be captured as prevailing thunder think
later period will be better handled in later forecasts and amendments
after convection forms.
Progged soundings also favor ceilings falling into IFR category for
Wednesday morning and not improving to MVFR until afternoon with the
passage of a warm front. This boundary will likely not reach KSTJ so
there is some potential for them to remain IFR through the day.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from Wednesday afternoon through Thursday
evening FOR KSZ025-057-060-102>105.
MO...FLASH FLOOD WATCH from Wednesday afternoon through Thursday
evening FOR MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054.
&&
$$
UPDATE...MJ
SHORT TERM...PMM
LONG TERM...Cutter
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS HASTINGS NE
103 PM CDT MON APR 15 2013
.UPDATE...
ISSUED AT 103 PM CDT MON APR 15 2013
CONFIDENCE HAS DIMINISHED IN SHORT-TERM CLOUD COVER AND THIS HAS
TEMP IMPLICATIONS AS WELL. WE/VE NOTED RAPID CLEARING FROM OGA-
TIF-ONL. THE ONLY MODEL ONTO THIS IS THE HRRR AND IT INDICATES
COMPLETELY CLEARING. WE HAVE NO CHOICE BUT TO MAKE ADJUSTMENTS BUT
THE MAGNITUDE AND EXTENT ARE NOT EASY.
UPDATE ISSUED AT 955 AM CDT MON APR 15 2013
A REINFORCING SHOT OF COLD AIR MOVED THRU THE FCST AREA THIS MRNG.
THE FRONTAL INVERSION WAS NEAR 2700 FT ON THE 12Z LBF/OAX
SOUNDINGS. DIFFERENTIAL ADVECTION WAS OCCURRING ABOVE AND BELOW
THE FRONTAL ZONE...WITH WAA IN THE MID-LVLS AHEAD OF A WEAK H7 LOW
OVER CO. THIS WAS THE CAUSE FOR THE RETURNS YOU SEE ON RADAR. ONLY
A FEW FLURRIES MADE IT TO THE GROUND AS THE LOW-LEVELS ARE DRY.
CIGS ARE MOSTLY 8-10K FT.
AS FOR THE FCST EXPECT A MAINLY OVC DAY. SOME BREAKS OR THIN SPOTS
ARE LIKELY WELL SE OF THE TRI-CITIES. SATL SHOWS CLEARING OVER NW
KS AND IT APPEARS TO BE ADVANCING NE. RAP MODEL DOES HAVE THE
TREND SO WILL UPDATE THE FCST TO SHOW SOME IMPROVEMENT WITH
DECREASING CLOUDS S OF HWY 6. WITH THIS IN MIND WILL LEAVE HIGH
TEMPS IN THE MID 50S DOWN THERE AS WELL. WITH OVC EXPECTED TO
REMAIN ALONG AND N OF HWY 6...WILL BE LOWERING HIGH TEMPS 3-6F FOR
OUR NRN COUNTIES.
UPDATE ISSUED AT 825 AM CDT MON APR 15 2013
SENT AN UPDATE TO BETTER REFLECT CURRENT CONDS. THIS INCLUDED
TAKING SKY UP TO OVC. A NOWCAST WAS ISSUED AT 815 AM AND HAVE
INCLUDED SCT FLURRIES IN THE FCST FROM THE TRI-CITIES N AND E.
REFLECTIVITY IS MOVING E AROUND 55 KTS. NEW ECHOES ARE DEVELOPING
W OF THE FCST AREA SO WILL REEVALUATE AS I GET INTO THE SWING OF
THINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON APR 15 2013
TEMPERATURES WILL CONTINUE THEIR DOWNWARD TREND TODAY AS COOLER AIR
CONTINUES TO FILTER IN ACROSS THE REGION BEHIND A SECONDARY COLD
FRONT WHICH SAGGED SOUTHWARD OVERNIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL ANOTHER 10 DEGREES OR SO FROM SUNDAYS
HIGHS.
WHILE SOME CLOUDS ARE STARTING TO FILTER IN ACROSS THE LOCAL
AREA FROM THE WEST THIS MORNING...EXPECT CLOUD COVER TO INCREASE
FURTHER THROUGHOUT THE DAY AS THE NEXT UPPER LEVEL DISTURBANCE
CROSSES THE INTERMOUNTAIN WEST. WHILE BOTH THE 00Z WRF AND 06Z NAM
ARE TRYING TO DEVELOP A BAND OF LIGHT PRECIP ACROSS MUCH OF THE
FORECAST AREA OVERNIGHT TONIGHT...MODELED SOUNDINGS INDICATE A
SIGNIFICANT SPREAD BETWEEN SURFACE TEMPS AND DEWPOINTS THROUGH AT
LEAST THE FIRST HALF OF THE NIGHT...WITH WESTERN AREAS BEGINNING
TO SATURATE AS WE ENTER THE EARLY MORNING HOURS TUESDAY. AS A
RESULT...WENT AHEAD AN TRIMMED BACK POPS A BIT DURING THE EVENING
AND OVERNIGHT HOURS...CONTINUING WITH ONLY SMALL CHANCES FOR SOME
LIGHT RAIN OR SNOW IN AN AREA OF ISENTROPIC LIFT AHEAD OF THIS
NEXT DISTURBANCE. EVEN IF PRECIPITATION IS REALIZED...DO NOT
EXPECT MUCH IN THE WAY OF ACCUMULATION...WITH A FEW HUNDREDTHS OF
LIQUID PRECIP EQUIVALENT AT MOST.
IN ADDITION TO TWEAKING DOWN PRECIP CHANCES SOME OVERNIGHT
TONIGHT...ALSO TWEAKED DOWN LOW TEMPERATURES A BIT TUESDAY MORNING TO
BRING CLOSER TO LATEST GUIDANCE AND TO ACCOUNT FOR THIS COOLER
AIRMASS. OTHERWISE...ONLY A FEW MINOR TWEAKS TO THE WIND/DEWPOINT
GRIDS WERE NECESSARY THIS MORNING...WITH NO SIGNIFICANT WEATHER
IMPACTS EXPECTED THROUGH THE SHORT TERM PERIODS AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON APR 15 2013
MAIN FORECAST CONCERNS LIE WITH MID WEEK PRECIPITATION CHANCES...AND
PLENTY OF DETAILS TO IRON OUT BETWEEN MODELS KEEPING CONFIDENCE ON
THE LOWER SIDE.
STARTING OFF THE LONG TERM PERIOD ON TUESDAY...OUTSIDE SOME
LINGERING PRECIPITATION CHANCES DURING THE MORNING ALONG A NARROW
BAND OF MID LEVEL FRONTOGENETICAL FORCING AND ISENTROPIC LIFT...THE
FORECAST IS QUIET...THOUGH WILL HAVE KEEP AN EYE ON THE POTENTIAL
FOR DRIZZLE ACROSS THE SRN PORTIONS OF THE CWA. THE CWA IS SITTING
UNDER SOUTHWESTERLY FLOW IN THE UPPER LEVELS...AHEAD OF ANOTHER
SYSTEM OVER THE ROCKIES...WHICH THROUGH THE DAYTIME HOURS DIGS
FURTHER SOUTH INTO THE ROCKIES. EXPECTING TO SEE EASTERLY WINDS
ACROSS THE CWA AS SFC LOW PRESSURE ORGANIZES OVER THE FOUR CORNERS
REGION. ALONG WITH THE EXPECTED CLOUD COVER AND COOLER AIR MASS IN
PLACE...THINKING HIGH TEMPERATURES IN THE MID 40S LOOKS REASONABLE.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT STILL LOOKING LIKE THE PRIMARY
ACTIVE TIME FRAME OF THE EXTENDED PERIOD...AND EVEN WITH THE EVENT
BEING THIS CLOSE...STILL PLENTY OF VARIATIONS BETWEEN MODELS AND
DETAILS TO IRON OUT. TUESDAY NIGHT...MAIN CONCERN IS PRECIPITATION
POTENTIAL INCREASING...WILL BEGIN TO SEE INCREASING LARGER SCALE
LIFT ACROSS THE REGION AS THE MAIN SYSTEM SHIFT EAST ACROSS THE
ROCKIES...BUT MODELS ARE SHOWING A SRLY LLJ JET NOSING RIGHT INTO
THE CWA. THERE ARE SOME DIFFERENCES BETWEEN MODELS WITH THE
STRENGTH OF THE LLJ...AND WITH THE AMOUNT OF ELEVATED INSTABILITY
AVAILABLE...BUT MENTION OF ISOLATED THUNDER REMAINS IN THE FORECAST
ACROSS SRN PORTIONS OF THE CWA. AS MENTIONED BY PREVIOUS
FORECAST...SOME MODELS CAME IN WARMER AND HAVE REMAINED THAT
WAY...BUT NOT ALL MODELS HAVE. THE ECMWF REMAINS ON THE NOTABLY
COOLER SIDE OF THINGS...5+ DEGREES COOLER IN SOME LOCATIONS. THIS
SOLUTION WOULD BRING A COMPLETE SWITCH OVER TO SNOW TUESDAY NIGHT
FOR A GOOD PORTION OF THE CWA...BUT WITH LITTLE SUPPORT FROM OTHER
MODELS...WILL BE KEEPING PRECIP TYPE AS MAINLY LIQUID WITH A RA/SN
MIX POSSIBLE IN THE NWRN CWA. THIS COOLER ECMWF SOLUTION CONTINUES
THROUGHOUT THE ENTIRE EVENT.
WEDNESDAY...DIDNT MAKE SIGNIFICANT CHANGES TO THE POPS...BUT AM
CONCERNED ABOUT HOW MUCH PRECIPITATION IS ACTUALLY GOING TO BE GOING
ON ONCE THE ACTIVITY FROM OVERNIGHT SLIDES OUT OF THE AREA. MODELS
GENERALLY SHOWING THE SAME BASIC STORY WITH THE MID/UPPER LEVEL
PATTERN THROUGH THE DAYTIME HOURS...CONTINUING ITS EASTWARD SLIDE
AND BY 00Z HAVING AN ELONGATED 700MB LOW ORIENTATED IN A SW/NE LINE
ACROSS WRN PORTIONS OF NEB/KS...WITH A MORE OPEN PATTERN AT 500MB.
AM A LITTLE CONCERNED ABOUT THE 00/06Z NAM RUNS...WHICH BOTH SHOWED
A MORE PRONOUNCED DRY SLOT/BREAK IN PRECIP DURING THE AFTERNOON...BUT
IT IS ALSO MORE ORGANIZED IN THE MID/UPPER LEVELS AND HAS THE LOW
FURTHER N/NE THAN OTHER SOLUTIONS. NOT PUTTING A LOT OF WEIGHT IN
IT...BUT IS SOMETHING TO KEEP AN EYE ON. ANOTHER QUESTION IS WHERE
THE ACCOMPANYING SFC COLD FRONT ENDS UP...AS THIS FRONT WILL PROVIDE
A FOCUS FOR THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON/EVENING
HOURS AS LARGE SCALE LIFT CONTINUES TO INCREASE WITH THE APPROACHING
SYSTEM. THIS TIME ITS THE GFS THAT IS CONCERNING...AS ITS PLACEMENT
OF THE SFC LOW AND FRONTAL BOUNDARY IS FURTHER NORTH THAN THE OTHER
SOLUTIONS...AND IF IT ENDS UP VERIFYING...OUR CWA /ESP THE SRN
PORTIONS/ WOULD BE LOOKING AT A BETTER POTENTIAL FOR
THUNDERSTORMS..INCLUDING SEVERE ONES. AT THIS POINT AM KEEPING THE
FORECAST TRENDED TOWARD THE FURTHER SOUTHWARD PLACEMENT OF THE SFC
FRONT AND ONLY AN ISOLATED MENTION OF THUNDER.
WITH ALL THE VARIATIONS BETWEEN MODELS WITH THE PRECIPITATION
THROUGH THE DAY AND SFC FRONT PLACEMENT...THERE IS A POTENTIAL FOR A
BUST ON AFTERNOON TEMPS...ESP ACROSS THE SOUTHEASTERN HALF. SOME
GUIDANCE/MODELS HAVE HIGHS IN THE 50S/NEAR 60 DEGREES IN THOSE
AREAS...DID BUMP HIGHS A COUPLE DEGREES...BUT WITH SOME MODELS
REMAINING ON THE COOLER SIDE DIDNT WANT TO BUY FULLY INTO THE WARMER
TEMPS QUITE YET.
WEDNESDAY NIGHT/THURSDAY...WHATEVER INSTABILITY THAT IS IN PLACE
OVER THE AREA IS EXPECTED TO QUICKLY FOCUS FURTHER SOUTHEAST OF THE
CWA WEDNESDAY NIGHT...AS THE AXIS OF THE MID/UPPER LEVEL SYSTEM
STARTS TO MOVE FURTHER INTO THE PLAINS...STILL PROVIDING PLENTY OF
LIFT ACROSS THE AREA...BUT BETTER PRECIPITATION CHANCES ARE EXPECTED
TO START SETTING UP OVER ERN PORTIONS OF THE CWA. DID BUMP UP POPS
A TOUCH DURING THE DAY THURSDAY...WITH BETTER AGREEMENT SHOWING THE
SYSTEM A LITTLE SLOWER TO MOVE EAST. MODEL DIFFERENCES WITH THE
THERMAL PROFILE REMAIN IN PLACE...LEAVING SOME QUESTION WITH HOW
QUICKLY A RA/SN MIX OR JUST SN BUILD IN FROM THE WEST. STILL
UNCERTAINTIES WITH ACCUMULATIONS BECAUSE OF THIS ALONG WITH THE
DIFFERENCES IN MODEL QPF ACROSS THE CWA /THE NAM AND SREF HAVE VERY
LITTLE/...BUT THE NORTHWESTERN HALF/THIRD OF THE CWA REMAINS THE
AREA WITH THE BEST POTENTIAL FOR ACCUMULATING SNOWFALL.
LOOKING AT THE FORECAST FOR THURSDAY NIGHT THROUGH
SUNDAY...NORTHWESTERLY FLOW SETS UP IN THE UPPER LEVELS AS THIS MID
WEEK SYSTEM SLIDES FURTHER EAST AND WITH RIDGING OFF THE WEST
COAST. THE FORECAST REMAINS DRY...WITH THE ONE EXCEPTION BEING ON
SUNDAY...WITH MODELS CONTINUING TO SHOW A WEAK UPPER LEVEL
DISTURBANCE SLIDING THROUGH THE REGION. SHOULD BEGIN TO SEE A
REBOUND IN TEMPERATURES...AS THE COLDER AIR SLIDES EAST ALONG WITH
THE MAIN SYSTEM...BUT AT THIS POINT NOT LOOKING AT A SIGNIFICANT WARM
UP...JUST ENOUGH OF ONE TO GET US AT LEAST BACK CLOSER TO AVERAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 103 PM CDT MON APR 15 2013
THIS AFTN: VFR MID-LEVEL CIGS. THERE IS A CHANCE CIGS COULD BECOME
SCT LATE. NW WINDS 10-15 KTS WILL BECOME N.
TNGT: VFR MID-LEVEL CIGS MAY DESCEND TO AROUND 5K FT. THERE IS A
VERY LOW PROB FOR A TOUCH OF MVFR -SN. CONFIDENCE IS NOT HIGH ENUF
TO INCLUDE IN THE TAF. N WINDS AROUND 10 KTS.
TUE THRU 18Z: VFR MID-LEVEL CIGS CONTINUE. NE WINDS 10-15 KTS.
CIG CONFIDENCE: AVERAGE
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: AVERAGE
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
955 AM CDT MON APR 15 2013
.UPDATE...
ISSUED AT 955 AM CDT MON APR 15 2013
A REINFORCING SHOT OF COLD AIR MOVED THRU THE FCST AREA THIS MRNG.
THE FRONTAL INVERSION WAS NEAR 2700 FT ON THE 12Z LBF/OAX
SOUNDINGS. DIFFERENTIAL ADVECTION WAS OCCURRING ABOVE AND BELOW
THE FRONTAL ZONE...WITH WAA IN THE MID-LVLS AHEAD OF A WEAK H7 LOW
OVER CO. THIS WAS THE CAUSE FOR THE RETURNS YOU SEE ON RADAR. ONLY
A FEW FLURRIES MADE IT TO THE GROUND AS THE LOW-LEVELS ARE DRY.
CIGS ARE MOSTLY 8-10K FT.
AS FOR THE FCST EXPECT A MAINLY OVC DAY. SOME BREAKS OR THIN SPOTS
ARE LIKELY WELL SE OF THE TRI-CITIES. SATL SHOWS CLEARING OVER NW
KS AND IT APPEARS TO BE ADVANCING NE. RAP MODEL DOES HAVE THE
TREND SO WILL UPDATE THE FCST TO SHOW SOME IMPROVEMENT WITH
DECREASING CLOUDS S OF HWY 6. WITH THIS IN MIND WILL LEAVE HIGH
TEMPS IN THE MID 50S DOWN THERE AS WELL. WITH OVC EXPECTED TO
REMAIN ALONG AND N OF HWY 6...WILL BE LOWERING HIGH TEMPS 3-6F FOR
OUR NRN COUNTIES.
UPDATE ISSUED AT 825 AM CDT MON APR 15 2013
SENT AN UPDATE TO BETTER REFLECT CURRENT CONDS. THIS INCLUDED
TAKING SKY UP TO OVC. A NOWCAST WAS ISSUED AT 815 AM AND HAVE
INCLUDED SCT FLURRIES IN THE FCST FROM THE TRI-CITIES N AND E.
REFLECTIVITY IS MOVING E AROUND 55 KTS. NEW ECHOES ARE DEVELOPING
W OF THE FCST AREA SO WILL REEVALUATE AS I GET INTO THE SWING OF
THINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT MON APR 15 2013
TEMPERATURES WILL CONTINUE THEIR DOWNWARD TREND TODAY AS COOLER AIR
CONTINUES TO FILTER IN ACROSS THE REGION BEHIND A SECONDARY COLD
FRONT WHICH SAGGED SOUTHWARD OVERNIGHT. AS A RESULT...EXPECT
AFTERNOON TEMPERATURES TO FALL ANOTHER 10 DEGREES OR SO FROM SUNDAYS
HIGHS.
WHILE SOME CLOUDS ARE STARTING TO FILTER IN ACROSS THE LOCAL
AREA FROM THE WEST THIS MORNING...EXPECT CLOUD COVER TO INCREASE
FURTHER THROUGHOUT THE DAY AS THE NEXT UPPER LEVEL DISTURBANCE
CROSSES THE INTERMOUNTAIN WEST. WHILE BOTH THE 00Z WRF AND 06Z NAM
ARE TRYING TO DEVELOP A BAND OF LIGHT PRECIP ACROSS MUCH OF THE
FORECAST AREA OVERNIGHT TONIGHT...MODELED SOUNDINGS INDICATE A
SIGNIFICANT SPREAD BETWEEN SURFACE TEMPS AND DEWPOINTS THROUGH AT
LEAST THE FIRST HALF OF THE NIGHT...WITH WESTERN AREAS BEGINNING
TO SATURATE AS WE ENTER THE EARLY MORNING HOURS TUESDAY. AS A
RESULT...WENT AHEAD AN TRIMMED BACK POPS A BIT DURING THE EVENING
AND OVERNIGHT HOURS...CONTINUING WITH ONLY SMALL CHANCES FOR SOME
LIGHT RAIN OR SNOW IN AN AREA OF ISENTROPIC LIFT AHEAD OF THIS
NEXT DISTURBANCE. EVEN IF PRECIPITATION IS REALIZED...DO NOT
EXPECT MUCH IN THE WAY OF ACCUMULATION...WITH A FEW HUNDREDTHS OF
LIQUID PRECIP EQUIVALENT AT MOST.
IN ADDITION TO TWEAKING DOWN PRECIP CHANCES SOME OVERNIGHT
TONIGHT...ALSO TWEAKED DOWN LOW TEMPERATURES A BIT TUESDAY MORNING TO
BRING CLOSER TO LATEST GUIDANCE AND TO ACCOUNT FOR THIS COOLER
AIRMASS. OTHERWISE...ONLY A FEW MINOR TWEAKS TO THE WIND/DEWPOINT
GRIDS WERE NECESSARY THIS MORNING...WITH NO SIGNIFICANT WEATHER
IMPACTS EXPECTED THROUGH THE SHORT TERM PERIODS AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 430 AM CDT MON APR 15 2013
MAIN FORECAST CONCERNS LIE WITH MID WEEK PRECIPITATION CHANCES...AND
PLENTY OF DETAILS TO IRON OUT BETWEEN MODELS KEEPING CONFIDENCE ON
THE LOWER SIDE.
STARTING OFF THE LONG TERM PERIOD ON TUESDAY...OUTSIDE SOME
LINGERING PRECIPITATION CHANCES DURING THE MORNING ALONG A NARROW
BAND OF MID LEVEL FRONTOGENETICAL FORCING AND ISENTROPIC LIFT...THE
FORECAST IS QUIET...THOUGH WILL HAVE KEEP AN EYE ON THE POTENTIAL
FOR DRIZZLE ACROSS THE SRN PORTIONS OF THE CWA. THE CWA IS SITTING
UNDER SOUTHWESTERLY FLOW IN THE UPPER LEVELS...AHEAD OF ANOTHER
SYSTEM OVER THE ROCKIES...WHICH THROUGH THE DAYTIME HOURS DIGS
FURTHER SOUTH INTO THE ROCKIES. EXPECTING TO SEE EASTERLY WINDS
ACROSS THE CWA AS SFC LOW PRESSURE ORGANIZES OVER THE FOUR CORNERS
REGION. ALONG WITH THE EXPECTED CLOUD COVER AND COOLER AIR MASS IN
PLACE...THINKING HIGH TEMPERATURES IN THE MID 40S LOOKS REASONABLE.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT STILL LOOKING LIKE THE PRIMARY
ACTIVE TIME FRAME OF THE EXTENDED PERIOD...AND EVEN WITH THE EVENT
BEING THIS CLOSE...STILL PLENTY OF VARIATIONS BETWEEN MODELS AND
DETAILS TO IRON OUT. TUESDAY NIGHT...MAIN CONCERN IS PRECIPITATION
POTENTIAL INCREASING...WILL BEGIN TO SEE INCREASING LARGER SCALE
LIFT ACROSS THE REGION AS THE MAIN SYSTEM SHIFT EAST ACROSS THE
ROCKIES...BUT MODELS ARE SHOWING A SRLY LLJ JET NOSING RIGHT INTO
THE CWA. THERE ARE SOME DIFFERENCES BETWEEN MODELS WITH THE
STRENGTH OF THE LLJ...AND WITH THE AMOUNT OF ELEVATED INSTABILITY
AVAILABLE...BUT MENTION OF ISOLATED THUNDER REMAINS IN THE FORECAST
ACROSS SRN PORTIONS OF THE CWA. AS MENTIONED BY PREVIOUS
FORECAST...SOME MODELS CAME IN WARMER AND HAVE REMAINED THAT
WAY...BUT NOT ALL MODELS HAVE. THE ECMWF REMAINS ON THE NOTABLY
COOLER SIDE OF THINGS...5+ DEGREES COOLER IN SOME LOCATIONS. THIS
SOLUTION WOULD BRING A COMPLETE SWITCH OVER TO SNOW TUESDAY NIGHT
FOR A GOOD PORTION OF THE CWA...BUT WITH LITTLE SUPPORT FROM OTHER
MODELS...WILL BE KEEPING PRECIP TYPE AS MAINLY LIQUID WITH A RA/SN
MIX POSSIBLE IN THE NWRN CWA. THIS COOLER ECMWF SOLUTION CONTINUES
THROUGHOUT THE ENTIRE EVENT.
WEDNESDAY...DIDNT MAKE SIGNIFICANT CHANGES TO THE POPS...BUT AM
CONCERNED ABOUT HOW MUCH PRECIPITATION IS ACTUALLY GOING TO BE GOING
ON ONCE THE ACTIVITY FROM OVERNIGHT SLIDES OUT OF THE AREA. MODELS
GENERALLY SHOWING THE SAME BASIC STORY WITH THE MID/UPPER LEVEL
PATTERN THROUGH THE DAYTIME HOURS...CONTINUING ITS EASTWARD SLIDE
AND BY 00Z HAVING AN ELONGATED 700MB LOW ORIENTATED IN A SW/NE LINE
ACROSS WRN PORTIONS OF NEB/KS...WITH A MORE OPEN PATTERN AT 500MB.
AM A LITTLE CONCERNED ABOUT THE 00/06Z NAM RUNS...WHICH BOTH SHOWED
A MORE PRONOUNCED DRY SLOT/BREAK IN PRECIP DURING THE AFTERNOON...BUT
IT IS ALSO MORE ORGANIZED IN THE MID/UPPER LEVELS AND HAS THE LOW
FURTHER N/NE THAN OTHER SOLUTIONS. NOT PUTTING A LOT OF WEIGHT IN
IT...BUT IS SOMETHING TO KEEP AN EYE ON. ANOTHER QUESTION IS WHERE
THE ACCOMPANYING SFC COLD FRONT ENDS UP...AS THIS FRONT WILL PROVIDE
A FOCUS FOR THUNDERSTORM DEVELOPMENT DURING THE AFTERNOON/EVENING
HOURS AS LARGE SCALE LIFT CONTINUES TO INCREASE WITH THE APPROACHING
SYSTEM. THIS TIME ITS THE GFS THAT IS CONCERNING...AS ITS PLACEMENT
OF THE SFC LOW AND FRONTAL BOUNDARY IS FURTHER NORTH THAN THE OTHER
SOLUTIONS...AND IF IT ENDS UP VERIFYING...OUR CWA /ESP THE SRN
PORTIONS/ WOULD BE LOOKING AT A BETTER POTENTIAL FOR
THUNDERSTORMS..INCLUDING SEVERE ONES. AT THIS POINT AM KEEPING THE
FORECAST TRENDED TOWARD THE FURTHER SOUTHWARD PLACEMENT OF THE SFC
FRONT AND ONLY AN ISOLATED MENTION OF THUNDER.
WITH ALL THE VARIATIONS BETWEEN MODELS WITH THE PRECIPITATION
THROUGH THE DAY AND SFC FRONT PLACEMENT...THERE IS A POTENTIAL FOR A
BUST ON AFTERNOON TEMPS...ESP ACROSS THE SOUTHEASTERN HALF. SOME
GUIDANCE/MODELS HAVE HIGHS IN THE 50S/NEAR 60 DEGREES IN THOSE
AREAS...DID BUMP HIGHS A COUPLE DEGREES...BUT WITH SOME MODELS
REMAINING ON THE COOLER SIDE DIDNT WANT TO BUY FULLY INTO THE WARMER
TEMPS QUITE YET.
WEDNESDAY NIGHT/THURSDAY...WHATEVER INSTABILITY THAT IS IN PLACE
OVER THE AREA IS EXPECTED TO QUICKLY FOCUS FURTHER SOUTHEAST OF THE
CWA WEDNESDAY NIGHT...AS THE AXIS OF THE MID/UPPER LEVEL SYSTEM
STARTS TO MOVE FURTHER INTO THE PLAINS...STILL PROVIDING PLENTY OF
LIFT ACROSS THE AREA...BUT BETTER PRECIPITATION CHANCES ARE EXPECTED
TO START SETTING UP OVER ERN PORTIONS OF THE CWA. DID BUMP UP POPS
A TOUCH DURING THE DAY THURSDAY...WITH BETTER AGREEMENT SHOWING THE
SYSTEM A LITTLE SLOWER TO MOVE EAST. MODEL DIFFERENCES WITH THE
THERMAL PROFILE REMAIN IN PLACE...LEAVING SOME QUESTION WITH HOW
QUICKLY A RA/SN MIX OR JUST SN BUILD IN FROM THE WEST. STILL
UNCERTAINTIES WITH ACCUMULATIONS BECAUSE OF THIS ALONG WITH THE
DIFFERENCES IN MODEL QPF ACROSS THE CWA /THE NAM AND SREF HAVE VERY
LITTLE/...BUT THE NORTHWESTERN HALF/THIRD OF THE CWA REMAINS THE
AREA WITH THE BEST POTENTIAL FOR ACCUMULATING SNOWFALL.
LOOKING AT THE FORECAST FOR THURSDAY NIGHT THROUGH
SUNDAY...NORTHWESTERLY FLOW SETS UP IN THE UPPER LEVELS AS THIS MID
WEEK SYSTEM SLIDES FURTHER EAST AND WITH RIDGING OFF THE WEST
COAST. THE FORECAST REMAINS DRY...WITH THE ONE EXCEPTION BEING ON
SUNDAY...WITH MODELS CONTINUING TO SHOW A WEAK UPPER LEVEL
DISTURBANCE SLIDING THROUGH THE REGION. SHOULD BEGIN TO SEE A
REBOUND IN TEMPERATURES...AS THE COLDER AIR SLIDES EAST ALONG WITH
THE MAIN SYSTEM...BUT AT THIS POINT NOT LOOKING AT A SIGNIFICANT WARM
UP...JUST ENOUGH OF ONE TO GET US AT LEAST BACK CLOSER TO AVERAGE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 605 AM CDT MON APR 15 2013
VFR CONDITIONS WILL PREVAIL AT KGRI FOR THE NEXT 24 HOURS. EXPECT
MID LEVEL CLOUD COVER TO INCREASE ACROSS THE LOCAL AREA OVER THE
NEXT COUPLE OF HOURS...WITH OVERCAST SKIES NEAR OR JUST BELOW
10KFT EXPECTED TO REMAIN THROUGH MOST OF THE PERIOD. NORTHWESTERLY
WINDS WILL INCREASE AROUND DAY BREAK...AND BACK AND BECOME
MORE NORTHERLY LATE IN THE DAY BEHIND A PASSING COLD FRONT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
802 PM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING ACCOMPANIED
BY RAIN SHOWERS. A RIDGE OF HIGH PRESSURE WILL BUILD SOUTH INTO
THE REGION FROM CANADA ON WEDNESDAY. A WARM FRONT WILL APPROACH
THE REGION ON THURSDAY. IT WILL WARM AND WINDY FRIDAY FOLLOWED BY
SHOWERS FRIDAY NIGHT AS ANOTHER COLD FRONT MOVES ACROSS THE NORTH
COUNTRY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 654 PM EDT TUESDAY...PRE-FRONTAL RAIN SHOWERS HAVE EXITED
THE NORTH COUNTRY...THOUGH RECENT COMPOSITE RADAR SHOWS A FAIRLY
SOLID LINE OF RAIN SHOWERS APPROACHING THE SAINT LAWRENCE VALLEY
AND NORTHERN ADIRONDACKS OF NEW YORK. THESE SHOWERS ARE TIED TO
THE COLD FRONT AND HAVE GONE WITH AREAL COVERAGE WORDING TO HANDLE
THESE SHOWERS AS THEY MOVE ACROSS THE NORTH COUNTRY. RAP ANALYSES
SHOW A 85-95KT MID-LEVEL JET STREAK ORIENTED NORMAL TO THE SFC
BOUNDARY WHICH SUGGESTS THAT THE FRONT WILL BE QUICK TO MOVE EAST.
EXPECT THAT THESE SHOWERS WILL CONTINUE TO PROGRESS STEADILY
EASTWARD...CLEARING THE NORTH COUNTRY AROUND 05Z OR SO. THERE
COULD BE SOME BRIEF DOWNPOURS WITH THESE SHOWERS AS THEY MOVE
EAST...THOUGH QPF AMOUNTS SHOULD BE ON THE LIGHT SIDE. BEST
INSTABILITY REMAINS WELL SOUTH SO NOT EXPECTING ANY THUNDER WITH
THIS ACTIVITY.
A SHARP WIND SHIFT TO WEST/WEST-NORTHWEST IS EXPECTED WITH
CLEARING SKIES AND A NOTICEABLY DRIER AIR MASS FILTERING INTO THE
REGION. UNTIL THAT TIME...HAVE RAISED DEWPOINTS UP SEVERAL DEGREES
WITH DRYING OCCURRING WITH THE FRONT THEREAFTER. HAVE LEFT
TEMPERATURES LARGELY UNCHANGED AND WILL EVALUATE AS THE EVENING
PROGRESSES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 357 PM EDT TUESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION
ON WEDNESDAY. CENTER OF THE HIGH REMAINS OVER THE JAMES BAY REGION
WITH SEASONABLY COOL NORTHERLY FLOW EXPECTED ACROSS THE NORTH
COUNTRY. THUS...TEMPERATURES WILL BE A LITTLE LOWER THAN ON TUESDAY
WITH HIGHS IN THE 50S. DRY WEATHER CONTINUES WEDNESDAY NIGHT
ALTHOUGH THERE WILL BE AN INCREASE IN CLOUDS WITH ONSET OF WARM AIR
ADVECTION AS HIGH PRESSURE MOVES FURTHER EAST AND RETURN SOUTHERLY
FLOW DEVELOPS BY THURSDAY MORNING. A WARM FRONT WILL APPROACH THE
REGION ON THURSDAY. HAVE GONE WITH CHANCE POPS FOR A FEW
SHOWERS...MAINLY OVER NORTHERN ZONES. DESPITE CLOUD
COVER...INCREASING SOUTHERLY FLOW WILL ALLOW FOR MILDER
TEMPS...WITH HIGHS WELL INTO THE 50S TO LOWER 60S. FURTHER
INCREASE IN SOUTHERLY FLOW THURSDAY NIGHT...SO EXPECT A MILD NIGHT
AND MAINLY DRY AS FORECAST AREA WILL BE IN WARM SECTOR.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 355 PM EDT TUESDAY...CONSISTENT FORECAST CONTINUES WITH
WARM MAX TEMPERATURES ON FRIDAY AS 850MB TEMPS INCREASE TO ABOUT
10C-12C. SOUTHERLY FLOW...WAA AND SOME BREAKS IN CLOUDS WILL WARM
SFC TEMPS INTO THE 60S AND L70S.
A COLD FRONT WILL APPROACH FROM THE WEST ON THE LATTER HALF OF
FRIDAY INTO FRIDAY NIGHT. THIS FRONT COULD TRIGGER SOME ISOLATED
TS...BUT PARAMETERS NOT QUITE LINING UP TIME-WISE. TEMP LAPSE
RATES OF 6+C/KM LOWERING AS AREA OF CAPE MOVES EASTWARD INTO NRN
NY. ALSO LIFTED INDICES STAYING ABOVE ZERO...SO HAVE NOT INCLUDED
TS IN FCST AT THIS TIME. WITH THIS SYSTEM...GEFS SHOWING PWATS
VALUES OF 2-3 STANDARD DEVIATIONS ABOVE NORMAL OVER THE NORTH
COUNTRY...WITH QPF AMOUNTS UP TO A HALF INCH THROUGH SATURDAY.
PRECIP AND COLD FRONT SHOULD EXIT ERN VT SOMETIME ON
SATURDAY...FOLLOWED BY HIGH PRESSURE BUILDING INTO THE GREAT
LAKES REGION. THIS RIDGE OF HIGH PRESSURE WILL CREST OVER THE
REGION SUNDAY NIGHT AND SLIDE EAST OVER NOVA SCOTIA ON MONDAY.
DRY CONDITIONS WILL LINGER INTO THE BEGINNING OF NEXT WEEK.
TEMPERATURES STARTING WARM WITH WAA AND SOUTHERLY FLOW AHEAD OF
THE COLD FRONT. A GENERAL COOLING TREND OVER THE WEEKEND BEHIND
THE FRONT. FRIDAY NT MIN TEMPS WILL BE IN THE 40S. SATURDAY AND
SUNDAY MAX TEMPS WILL BE IN THE 40S TO L50S. SATURDAY NT AND
SUNDAY NT EXPECT BELOW NORMAL MIN TEMPS IN THE L20S-L30S. TEMPS
WILL WARM SLIGHTLY AS THE HIGH PRESSURE CRESTS OVER THE REGION
AND WE GET A RETURN TO SOUTHERLY FLOW. MONDAY MAX TEMPS WILL
REACH THE M40S-U50S AND MIN TEMPS MONDAY NIGHT WILL BE IN THE
M20S-M30S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 00Z WEDNESDAY...BAND OF SHOWERS WILL EXIT NORTHERN NEW
YORK AND VERMONT BY 03Z. VISIBILITIES WITHIN THIS BAND OF SHOWERS
WILL BE IN THE VFR AND MVFR CATEGORIES. CEILINGS WILL ALSO BE IN
THE MVFR AND VFR CATEGORIES THROUGH 12Z WITH PERIODS OF IFR AT
KSLK. LOOK FOR A WIND SHIFT TO THE WEST AND NORTHWEST AFTER 02Z...
WITH GUSTY WINDS IN THE 15 TO 30 KNOT RANGE BEFORE THE WIND SHIFT.
EXPECT MVFR TO VFR CEILINGS ALL AREAS AFTER 12Z WITH NO ADDITIONAL
PRECIPITATION EXPECTED.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
00Z THURSDAY THROUGH 12Z THURSDAY...VFR CONDITIONS EXPECTED AS A
RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION.
12Z THURSDAY THROUGH 00Z FRIDAY...VFR/AREAS OF MVFR POSSIBLE AS A
WARM FRONT WILL BRING A CHANCE OF RAIN SHOWERS TO NY. VFR
EXPECTED OVER VT.
00Z FRIDAY THROUGH 00Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED.
00Z SATURDAY THROUGH 00Z SUNDAY...VFR/MVFR CONDITIONS AS COLD
FRONT BRINGS RAIN ACROSS THE NORTH COUNTRY.
00Z SUNDAY ONWARD...VFR CONDITIONS AS HIGH PRESSURE BUILDS INTO
THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS/LOCONTO
SHORT TERM...RJS
LONG TERM...KGM
AVIATION...EVENSON/KGM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1040 PM EDT TUE APR 16 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS UNTIL A COLD
FRONT CROSSES THE REGION LATE FRIDAY AND FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 1040 PM TUESDAY...
MAIN FORECAST CONCERNS OVERNIGHT INTO WEDNESDAY CENTER ON TWO ITEMS:
1.) EXTENT OF FOG OVERNIGHT AND POTENTIAL FOR DENSE FOG; 2.) IF BAND
OF CONVECTION DRIFTING ESE ACROSS WV EARLY THIS EVENING WILL HAVE
ANY IMPACTS ON OUR WEATHER BY MORNING.
AREAS OF BROKEN STRATOCU EARLIER THIS EVENING HAVE GAVE WAY TO
EITHER CLEAR SKIES OR SCATTERED PATCHES OF STRATOCU. TEMPS HAVE
COOLED INTO THE 60S AREAWIDE LATE THIS EVENING WHILE SFC DEWPOINTS
HOLD IN THE MID-UPPER 50S TO NEAR 60. LIGHT S-SW WIND STILL BEING
REPORTED BY MANY SITES THOUGH SOME AWOS SITES IN THE SOUTH HAVE GONE
CALM. SINCE SKIES EXPECTED TO REMAIN MOSTLY CLEAR ACROSS THE SOUTH
AND EAST SECTIONS OF FORECAST AREA...WILL LIKELY SEE AREAS OF FOG
DEVELOP BETWEEN 3 AM - 5 AM WITH POCKETS OF DENSE FOG PROBABLE NEAR
BODIES OF WATER. DO NOT ANTICIPATE DENSE FOG BEING WIDESPREAD ENOUGH
TO REQUIRE THE ISSUANCE OF AN ADVISORY. ACROSS THE
PIEDMONT...ESPECIALLY THE NW PIEDMONT...CLOUD DEBRIS BLOW OFF FROM
CONVECTION CROSSING THE LOWER OH VALLEY AND CENTRAL APPALACHIANS
WILL LIKELY PROHIBIT FOG FORMATION OVERNIGHT. MIN TEMP FORECAST
APPEARS ON TARGET...55-60 DEGREES.
AREA OF CONVECTION CROSSING THE LOWER OH VALLEY AND CENTRAL
APPALACHIANS DRIFTING ESE WHILE INDIVIDUAL CELLS MOVING EAST.
MODELS VERIFYING POORLY WITH THIS SYSTEM THOUGH LATEST HRRR RADAR
PROJECTION NOT TOO BAD WITH ITS RENDITION AT 03Z. THE RAPID REFRESH
MODEL BRINGS SCATTERED SHOWERS CLOSE TO OUR NW COUNTIES BETWEEN
9Z-12Z. THIS MODEL MAY BE ONTO SOMETHING AS 00Z ANALYSIS DEPICTS
BEST 850MB THETA E ADVECTION ACROSS THE TN AND LOWER OH
VALLEY...EXTENDING EWD INTO VA. THIS SUGGEST A FEW SHOWERS MAY SKIRT
OUR FAR NRN COUNTIES EARLY WED. THUS HAVE INTRODUCED A
SLIGHT/SMALL CHANCE POP ACROSS THIS REGION EARLY WED.
THIS SFC FEATURE MAY END UP BEING A FOCUS FOR ADDITIONAL CONVECTIVE
DEVELOPMENT WEDNESDAY AFTERNOON. MID LEVEL LAPSE RATES PROJECTED TO
BE NEAR 7 DEG C WHILE SFC BASED CAPE CLOSE TO 1000 J/KG BY MID-LATE
AFTERNOON. WOULD NOT BE SURPRISED TO SEE SOME HAIL WITH THE STRONGER
STORMS WITH MARGINALLY SEVERE HAIL POSSIBLE. DAMAGING WIND THREAT
APPEARS WEAK AT THIS TIME. HAVE ADJUSTED SKY FORECAST AS WELL AS
EXTEND POPS A LITTLE FARTHER A SOUTH WEDNESDAY AFTERNOON AS
SCATTERED SHOWERS AND STORMS WILL LIKELY DRIFT SEWD. NOT EXPECTING
MUCH ACTIVITY TOO FAR SOUTH OF HIGHWAY 64 AS MODEL SOUNDINGS SUGGEST
MID LEVEL CAP WILL HOLD IN THIS REGION. DO NOT ADJUST MAX TEMPS BUT
IF CLOUD OR SHOWER COVERAGE MORE EXTENSIVE THAN CURRENT
THINKING...MAX TAMPS ACROSS THE NW AND FAR NORTHERN PIEDMONT MAY
NEED TO BE ADJUSTED DOWN A FEW DEGREES. -WSS
GOOD RADIATIONAL COOLING AGAIN WED NIGHT...WITH AREAS OF RADIATION
FOG...AND NEAR PERSISTENCE LOWS IN THE MIDDLE TO UPPER 50S. -MWS
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...
UPPER RIDGE AXIS SHIFTS OFFSHORE AND SURFACE RIDGING WEAKENS ON
THURSDAY. PLENTY OF SUN AND SOUTHERLY FLOW WILL ALLOW HIGHS TO REACH
THE LOWER 80S..BUT LACK OF FORCING AND A LINGERING CAP ALOFT WILL
PRECLUDE CONVECTION OF SIGNIFICANCE. FLOW WILL GRADUALLY VEER AS THE
RIDGING CONTINUES TO WEAKEN OVERNIGHT AND SCATTERED SHOWERS ARE
POSSIBLE IN THE WEST WITH UPSLOPE COMPONENT AND INCREASING MOISTURE
ADVECTION. CLOUDINESS AND WARM ADVECTION WILL INHIBIT DIURNAL
TEMPERATURE CRASH AND MINS WILL BE MILD...AROUND 60.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM TUESDAY...
A STRONG COLD FRONT WILL BE APPROACHING FROM THE WEST AND MOVING
RATHER SLOWLY ACROSS THE STATE ON FRIDAY. THE PARENT LOW WILL BE
WELL TO THE NORTH AND LIFTING QUICKLY NORTHEAST. TIMING WILL BE
FAVORABLE AND TEMPERATURES WILL GET OFF TO A WARM START BUT WITH
LIMITED INSOLATION...ESPECIALLY WEST. THIS SOMEWHAT LIMITED
INSTABILITY COULD BE THE MAJOR INHIBITING FACTOR AS ELEMENTS
FAVORABLE FOR STRONGER TO SEVERE CONVECTION WILL BE FAIRLY
WELL-ALIGNED IN THE LATE DAY TO EARLY OVERNIGHT AS TO MAXIMIZE DEEP
LIFT. WILL INCREASE POPS FROM CHANCE IN THE WEST EARLY TO LIKELY IN
THE AFTERNOON...WITH LIKELY POPS MIGRATING INTO THE EAST OVERNIGHT
BEFORE TAPERING OFF BY SATURDAY MORNING. HIGHS ON FRIDAY WILL TOP
OUT IN THE MID 70S WEST TO LOWER 80S EAST. COLD AIR ADVECTION WILL
GET UNDERWAY AFTER MIDNIGHT WITH MINS FALLING TO THE UPPER 40S WEST
TO LOW AND MID 50S EAST.
HIGH PRESSURE BUILDING UP THE OHIO VALLEY WILL PROVIDE US WITH A DRY
SOMEWHAT COOLER THAN SEASONABLE WEEKEND. HIGHS SATURDAY AND SUNDAY
WILL BE IN THE 60S...SUNDAY MORNINGS LOW WILL BE IN THE 40S.
THE FRONT THAT PASSED OFFSHORE ON SATURDAY MORNING WILL BE LINGERING
ALONG THE COAST AND IS PROGGED TO RETROGRESS TOWARDS THE COAST
MONDAY WITH AN INVERTED TROF ALONG THE COAST EDGING UP AGAINST THE
COOL RIDGE. THIS WILL REINFORCE COOL AIR WITH GOOD NORTHEAST FLOW
AND POSSIBLY SOME SHOWERS ON TUESDAY. HIGHS MONDAY AND TUESDAY WILL
BE MOSTLY IN THE MID TO UPPER 60S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 820 PM TUESDAY...
SKIES HAVE GENERALLY CLEARED ACROSS THE AREA THIS EVENING WITH THE
LOSS OF DAYTIME HEATING... WITH ONLY A FEW LOCATIONS ACROSS EASTERN
AND SOUTHERN PORTIONS OF THE AREA REPORTING A VFR COULD DECK AROUND
5 TO 8 KFT. EXPECT THE VFR CONDITIONS TO CONTINUE FOR THE REST OF
THIS EVENING. HOWEVER... WITH LIGHT AND VARIABLE TO CALM WINDS AND
MOSTLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED THINK WE WILL SEE
SUB-VFR CONDITIONS DEVELOP AGAIN OVERNIGHT. HOWEVER... EXPECT THE
WORST CONDITIONS (LIFR/IFR) TO BE ACROSS THE EASTERN TAF SITES...
WHERE WE ARE LIKELY TO SEE VISBYS DROP INTO THE IFR/LIFR RANGE...
ALONG WITH LOW STRATUS. FURTHER WEST WE MAY SEE MID AND HIGH LEVEL
CLOUD COVER INCREASE LATE IN THE NIGHT (EARLY WEDNESDAY MORNING)...
ALONG WITH MORE OF A VEERING WEST-SOUTHWESTERLY LIGHT BREEZE.
THUS... WILL GO WITH MVFR VISBYS NEAR SUNRISE AT KGSO AND KINT.
HOWEVER... CANT COMPLETELY RULE OUT A BRIEF BROKEN IFR DECK OF
CLOUDS DEVELOPING SHORTLY AFTER SUNRISE AT KGSO AND KINT... BEFORE
QUICKLY SCATTERING OUT (CONFIDENCE IS TOO LOW TO INCLUDE AT THIS
TIME IN THE TAFS). FURTHER EAST AT KFAY/KRDU/KRWI... WE WILL LIKELY
SEE A TRANSITION FROM THE VERY LOW STATUS AND FOG TO IFR STRATUS AND
EVENTUALLY VFR CONDITIONS BY 15Z WEDNESDAY MORNING. IN ADDITION TO
THE THREAT FOR FOG AND LOW STRATUS TONIGHT.... WE WILL NEED TO KEEP
AN EYE ON THE SHOWERS AND THUNDERSTORMS WELL NORTH OF THE AREA
(ALONG A COLD FRONT). WHILE WE DO NOT ANTICIPATE THE FRONTAL ZONE
DRIFTING SOUTHWARD INTO THE AREA TONIGHT... SOME HI-RES MODELS ARE
HINTING AT THE POSSIBILITY OF THE SHOWERS AND STORMS NOW MAKING IT
INTO OUR NORTHWEST PIEDMONT CLOSE TO DAYBREAK WEDNESDAY. WHILE THIS
SOLUTION IS NOT CURRENTLY FAVORED WE WILL NEED TO WATCH THIS LINE AS
IT BEGINS TO DRIFT SOUTHWARD. GIVEN THE TIME OF DAY (NIGHT TIME...
NOCTURNAL COOLING) EXPECT WE SHOULD SEE AN OVERALL WEAKENING
TREND... EVENTUALLY DISSIPATING AS IT APPROACHES OUR REGION.
HOWEVER... WE MAY SEE SOME REDEVELOPMENT ON WEDNESDAY AFTERNOON AND
POSSIBLY SEE SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
MAKE IT INTO OUR NORTH/NORTHWEST PIEDMONT... POSSIBLY AFFECTING
KGSO/KINT/KRDU.
LOOKING AHEAD: THERE IS A MEDIUM CHANCE OF EARLY MORNING FOG AND/OR
STRATUS THROUGH THU MORNING...PARTICULARLY AT EASTERN
TERMINALS...AND A HIGH CHANCE OF STRATUS FRI TERMINAL-WIDE FRI
MORNING. VFR CONDITIONS WILL OTHERWISE PREVAIL UNTIL A COLD FRONT
AND PRECEDING SHOWERS AND STORMS -- AND SUB-VFR CONDITIONS -- AFFECT
OUR REGION FRI-FRI NIGHT.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...WSS/MWS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...BSD/MWS
AREA FORECAST DISCUSSION
NWS NORMAN OK
1151 PM CDT SUN APR 14 2013
.UPDATE...
LOWERED POPS FOR THE REST OF THE NIGHT...
&&
.DISCUSSION...
ONLY HAD A FEW UPDRAFTS DEVELOP THIS EVENING ALONG THE COLD FRONT
CURRENTLY MOVING SOUTHWARD ACROSS THE SOUTHERN PLAINS. THROUGH 11
PM CDT...ALL CONVECTION HAD CEASED...AS A DRY AND STABLE AIR MASS
WAS QUICK TO SPREAD ACROSS NORTHERN OKLAHOMA AND KANSAS ON THE
HEELS OF THE FRONT. WEATHER SHOULD REMAIN QUIET THROUGH THE
OVERNIGHT FOR OKLAHOMA AND WESTERN NORTH TEXAS. LOWS WILL BE MILD
FROM THE RED RIVER VALLEY...UPPER 50S TO LOWER 60S...TO SEASONABLE
ACROSS NORTHERN AND NORTHWESTERN OKLAHOMA...MID TO UPPER 40S.
WINDS ACROSS SOUTHERN OKLAHOMA AND NORTHERN TEXAS WILL CONTINUE TO
SHIFT OUT OF THE NORTHWEST. WITH WINDS BEHIND THE FRONT BREEZY AT
TIMES...20 TO 25 MPH.
JTK
&&
.PREV DISCUSSION... /ISSUED 639 PM CDT SUN APR 14 2013/
UPDATE...
MESOSCALE ENVIRONMENT UPDATE...
DISCUSSION...
A FEW WEAK UPDRAFTS HAVE FINALLY BEEN ABLE TO FIRE ACROSS NORTH
CENTRAL OKLAHOMA WITHIN A REGION OF CU DEVELOPMENT FOCUSED ALONG
THE FRONTAL BOUNDARY. 14/23Z SURFACE ANALYSIS PLACES THE FRONT
FROM SWRN IA SOUTHWEST THROUGH THE TX PANHANDLE. 21Z RAP SOUNDINGS
AT 23Z JUST AHEAD OF THE FRONT REVEAL A FAIRLY DECENT MIXING FROM
THE SURFACE THROUGH APPROXIMATELY 850MB. WITH SKINNY CAPE
PROFILES...MLCAPE VALUES ON RANGE FROM 250 TO 500 J/KG.
HOWEVER...RAP 0-1KM AGL COMPUTED CAPE (LOW LVL CAPE) SHOWS A NICE
POCKET OF 400 TO 550 J/KG NEAR WHERE 50-60 DPTS HAVE POOLED NEAR
THE INTERSECTION OF THE DRY LINE AND COLD FRONT ACROSS N CENTRAL
OK.
UPSTREAM SURFACE ANALYSIS WOULD INDICATE A SHALLOW PROFILE FOR THE
COLD FRONT. AT 14/23Z...TEMPS BEHIND THE FRONT RANGE FROM THE
UPPER 60S/LOWER 70S ACROSS SRN KS...TO THE MID 50S/LOWER 60S
ACROSS SRN NE. THE COMBINATION OF MIXING AT THE SURFACE...MODEST
INSTABILITY AND WEAK LIFT FROM THE FRONT ARE LIKELY REASON THE
CURRENT UPDRAFTS...WHICH DEVELOPED APPROXIMATELY 530ISH...HAVE
CONTINUED TO STRUGGLE.
HOWEVER...RADAR ANALYSIS INDICATES CURRENT CONVECTION MAY BE
DEVELOPING ALONG A PRE-FRONTAL WIND SHIFT/SFC TROUGH...AS A
SECOND BOUNDARY IS DEFINED ON KVNX FROM NEAR CARRIER TO BRAMAN.
BEHIND THIS BOUNDARY...AIR IS A BIT COOLER (LOWER 70S) AND DRIER
(MID 50S DPTS). AS THIS BOUNDARY CATCHES UP WITH THE ONGOING
CONVECTION...IT COULD OFFER SOME ENHANCEMENT.
OVERALL...SEVERE THREAT FOR NORTH CENTRAL OKLAHOMA LOOKS TO BE
DIMINISHING SLIGHTLY FOR THE MOMENT. HOWEVER...IF THE SECONDARY
BOUNDARY OFFERS A BETTER SOURCE OF LIFT...ONE COULD NOT RULE OUT
AT THIS TIME A FEW STRONG TO SEVERE STORMS DEVELOPING. HAIL TO THE
SIZE OF QUARTERS AND WINDS NEAR 60 MPH WOULD BE THE PRIMARY
CONCERNS.
JTK
PREV DISCUSSION... /ISSUED 238 PM CDT SUN APR 14 2013/
DISCUSSION...
COLD FRONT MOVING THROUGH NORTHWEST OKLAHOMA WILL CONTINUE TO MOVE
SOUTH AND EAST ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT. A
FEW STORMS MAY DEVELOP ALONG THE FRONT LATER TODAY ACROSS MAINLY
NORTH CENTRAL OKLAHOMA. ENOUGH INSTABILITY WILL EXIST FOR THE
POSSIBILITY OF SEVERE WEATHER ASSOCIATED WITH THESE STORMS.
THIS FRONT WILL STALL LATE TONIGHT AND HANG OUT NEAR OR JUST
SOUTH OF THE I-44 CORRIDOR ON MONDAY. WITH NO STRONG FORCING AND
SOME CAPPING ISSUES MUCH OF MONDAY SHOULD REMAIN DRY. THIS FRONT
IS THEN EXPECTED TO TRY AND RETREAT BACK NORTH MONDAY NIGHT AS IT
IS INFLUENCED BY THE STRONGER STORM SYSTEM THAT WILL APPROACH THE
AREA LATER THIS WEEK. AN ISOLATED STORM OR TWO MAY TRY TO DEVELOP
ALONG FRONT OR DRYLINE LATE TUESDAY AFTN INTO THE EVENING HOURS
WITH PERHAPS A BIT BETTER CHANCE TUESDAY NIGHT WITH AID OF
DEVELOPING LLJ.. MAINLY CENTRAL INTO NORTHERN OKLAHOMA.
BY THE TIME WE GET TO WEDNESDAY... SIGNIFICANT DIFFERENCES CONT TO
REMAIN BETWEEN THE MODELS IN LOCATION OF SFC BOUNDARIES. THE
LATEST GFS CONT TO WANT AND TRY TO LIFT THE BOUNDARY WELL NORTH
INTO KANSAS WITH DRYLINE NEAR THE OK/TX BORDER WED AFTN... PUTTING
ALL OF THE AREA IN WARM SECTOR AND A MUCH HIGHER PROBABILITY OF
STRONG/SEVERE STORMS AND HEAVY RAIN ACROSS MUCH OF THE AREA.
HOWEVER... EURO KEEPS BOUNDARY MUCH FARTHER SOUTH AND THIS MAKES
MORE SENSE AS COLDER AIR TO THE NORTH OF THE FRONT WILL BE HARD TO
DISLODGE AND WITH ABUNDANT CLOUD COVER AND PERHAPS ONGOING PRECIP
HAVE A HARD TIME SEEING THIS BOUNDARY MOVE AS FAR NORTH AS GFS
SEEMS TO THINK. WILL THEREFORE CONT TO FOLLOW THE EURO AND KEEP
THE SFC BOUNDARY NEAR OF JUST NORTH OF I-44 CORRIDOR DURING THE
DAY ON WEDNESDAY BEFORE IT SURGES SOUTH LATE WEDNESDAY AND
WEDNESDAY NIGHT.
MUCH COLDER AIRMASS WILL THEN SURGE SOUTH OVERSPREADING THE AREA
WITH A CHANCE TO SEE SOME WINTRY PRECIP... HOWEVER LATEST TRENDS
CONT TO SHOW THIS BEING LESS OF A POSSIBILITY. FOR NOW WILL KEEP A
MENTION OF THIS FOR CONSISTENCY SAKE.
ANOTHER FREEZE MAY THEN OCCUR ACROSS PARTS OF NORTHERN OKLAHOMA
THURSDAY MORNING AND THEN AGAIN FRIDAY MORNING. FREEZING TEMPS
COULD GET NEAR CENTRAL AND INTO SOUTHWEST OKLAHOMA FRIDAY MORNING.
ANOTHER WEAKER FRONT WILL APPROACH NEXT WEEKEND... KEEPING TEMPS
BELOW NORMAL THROUGH REMAINDER OF EXTENDED.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 54 73 55 73 / 10 10 10 10
HOBART OK 48 72 52 74 / 10 10 10 10
WICHITA FALLS TX 55 83 61 87 / 0 10 10 10
GAGE OK 44 66 43 64 / 10 0 10 10
PONCA CITY OK 50 65 46 63 / 40 10 20 10
DURANT OK 64 84 65 83 / 0 10 20 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/02
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
809 PM MDT TUE APR 16 2013
.UPDATE...
ISSUED AT 802 PM MDT TUE APR 16 2013
02Z SURFACE ANALYSIS HAD LOW PRESSURE OVER SOUTH CENTRAL CO WITH
INVERTED TROUGH INTO SOUTHEAST MT. 00Z UPPER AIR ANALYSIS HAD
110KT JET STREAK FROM NORTH CENTRAL CO INTO NORTHWEST SD WITH THE
RIGHT ENTRANCE REGION OF JET RESPONSIBLE FOR BURST OF SN NOW SHIFTING
EAST OF THE BLACK HILLS INTO CENTRAL PORTIONS OF SD. 2-4 INCHES
FELL SOUTHWEST SD...SEE LOCAL STORM REPORTS. RATHER STRONG
850-700MB FRONTOGENESIS NOTED BELOW JET. 00Z RAP DEPICTED FIRST
AREA OF PRECIPITATION DECENTLY...SHIFTING TO THE NORTH AND EAST
THIS EVENING. NEXT IMPULSE APPEARS TO BE OVER SOUTHWEST UT IN LEFT
EXIT REGION OF 100KT JET STREAK PER WATER VAPOUR. THERE MIGHT EVEN
BE AN IMPULSE OVER NORTH CENTRAL CO. ACTIVITY WILL MOVE NORTHEAST
OVERNIGHT BRINGING ANOTHER BURST OR TWO OF MODERATE/HEAVY
SNOW...ESPECIALLY ACROSS SOUTHWEST PORTIONS OF CWA. LATEST
GUIDANCE SUGGESTS 3-6 INCHES ACCUMULATION OVERNIGHT...AND THAT IS
PRETTY CLOSE TO CURRENT FORECAST. WILL LEAVE CURRENT HEADLINES AND
GIST OF FORECAST INTACT...BUT WILL CONTINUE TO WATCH ANY SHIFTS OF
MAIN PRECIPITATION BAND THROUGH THE NIGHT.
&&
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 228 PM MDT TUE APR 16 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHWESTERLY COLORADO
WITH HIGH OVER THE MIDWEST. UPPER LEVEL ANALYSIS PLACES DEEP TROF
OVER THE WESTERN CONUS STRETCHING FROM THE NORTHERN ROCKIES INTO
THE GREAT BASIN. INITIAL WAVES EJECTING AHEAD TO THE TROF THRU
SWRLY FLOW INTO OUR AREA CONTINUE TO BRING BROAD AREA OF SNOW OVER
MUCH OF THE CWA. ACCUMULATIONS HAVE BEEN REPORTED OVER THE SWRN
CWA...THOUGH OVER THE SODAK PLAINS SNOW CONTINUES TO MELT ON
ROADWAYS.
FOR TONIGHT...TROF CONTINUES TO DEEPEN AND STARTS TO SLOWLY SHIFT
TO THE EAST. AS IT DOES...BROAD SCALE LIFT DEVELOPS OVER THE AREA
BRINGING INCREASING SNOWFALL RATES. WITH THIS ALONG WITH LACK OF
INSOLATION...EXPECT SNOW TO START ACCUMULATING OVER REMAINING PTNS
OF THE SODAK PLAINS LATE THIS AFT INTO EARLY THIS EVE. SOME
UPSLOPE ENHANCEMENT MAY DEVELOP OVER THE ERN FOOTHILLS WITH
EASTERLY COMPONENT TO LOW LEVEL FLOW POSSIBLY RESULTING IN SOME
LOCALLY HIGHER AMOUNTS.
ON WEDNESDAY...UPPER TROF CONTINUES TO WORK ITS WAY EAST WITH AXIS
STRETCHING FROM SRN SASKATCHEWAN TOWARDS THE FOUR CORNERS REGION BY
LATE AFTERNOON. BROAD SCALE LIFT CONTINUES THROUGH MOST OF THE DAY
WITH SNOW CONTINUING. SFC LOW PUSHES FROM COLORADO INTO THE PLAINS
WITH PRESSURE GRADIENT TIGHTEN SOME OVER OUR AREA BRINGING BREEZY
CONDITIONS ALONG WITH SOME BLOWING/DRIFTING SNOW. BY LATE
AFTERNOON INTO THE EVENING...TROF AXIS WILL SLOWLY WORK ITS WAY
EAST INTO THE CWA WITH RIDGING QUICKLY DEVELOPING IN ITS WAKE.
SNOW WILL THEN SLOWLY START DIMINISHING FROM WEST TO EAST...LINGERING
OVER SOUTH CENTRAL SD INTO THE MORNING.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 228 PM MDT TUE APR 16 2013
WINTER STORM WILL EXIT THE REGION WEST TO EAST ON THURSDAY WITH
LINGERING SNOW POSSIBLE ACROSS SOUTH CENTRAL SD THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS ARE EXPECTED THURSDAY NIGHT AND FRIDAY AS
A SHORT WAVE RIDGE CROSSES THE NORTHERN PLAINS. A FEW NORTHERN
STREAM WAVES WILL CROSS THE REGION FRIDAY NIGHT THROUGH
MONDAY...BRINGING ADDITIONAL CHANCES FOR LIGHT PRECIPITATION.
TEMPERATURES WILL REMAIN WELL BELOW AVERAGE THROUGH THE EXTENDED
PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 517 PM MDT TUE APR 16 2013
WIDESPREAD IFR/LIFR CONDITIONS DUE TO SN WILL CONTINUE THROUGH
WEDNESDAY AFTERNOON ACROSS NORTHEAST WY AND MUCH OF WESTERN SD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
SDZ024>032-041-042-072>074.
WINTER STORM WARNING UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
SDZ043-044-046-047-049.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
SDZ012>014.
WY...WINTER STORM WARNING UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
WYZ054>058.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
WYZ071.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
644 PM CDT TUE APR 16 2013
.DISCUSSION...
LOOK FOR CHALLENGING FLIGHT WEATHER CONDITIONS TO DEVELOP ACROSS
WEST CENTRAL TEXAS DURING THE NEXT 6 HOURS. AVIATION BELOW HAS
DETAILS.
&&
.AVIATION...
MODELS THIS CYCLE CONTINUE TO INDICATE STRATUS AND MVFR CEILINGS
WILL RETURN TO ALL OF WEST CENTRAL TEXAS BY 06Z TONIGHT. THE NAM
AND GFS 925 MB RELATIVE HUMIDITY FIELDS INCREASE TO NEAR
SATURATION BY 06Z ACROSS ALL OF WEST CENTRAL TEXAS. PLUS...THE GFS
AND NAM MOS GUIDANCE BOTH HOLD MVFR CEILINGS AT ALL FIVE TERMINALS
WELL INTO TOMORROW AFTERNOON. OUR PREVIOUS AVIATION FORECAST
PACKAGE RETURNED VFR CONDITIONS TO ALL FIVE TERMINALS BY 15Z
TOMORROW MORNING. HOWEVER...ALL INDICATORS SUGGEST THE MVFR
CEILINGS WILL LIKELY HOLD UNTIL AROUND 18Z TOMORROW AFTERNOON.
SO...THE NEW TERMINALS HOLD MVFR CEILINGS UNTIL 18Z.
ALSO...A WEAK FRONTAL BOUNDARY HAS STALLED NEAR A SWEETWATER TO
ALBANY LINE. THIS SURFACE BOUNDARY MAY INITIATE SHOWERS AND
THUNDERSTORMS LATER THIS EVENING. HOWEVER...I DECIDED NOT TO
INCLUDE ANY THUNDER IN THE ABILENE TERMINAL BECAUSE MY CONFIDENCE
FOR WHEN AND WHERE THIS CONVECTION MAY INITIATE IS NOT VERY HIGH.
HUBER
&&
.PREV DISCUSSION... /ISSUED 340 PM CDT TUE APR 16 2013/
SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 68 86 56 62 36 / 20 20 40 10 5
SAN ANGELO 70 91 58 65 38 / 10 20 30 10 5
JUNCTION 70 89 63 70 39 / 5 20 50 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1223 PM CDT MON APR 15 2013
.UPDATE...
UPDATED TO ADJUST HIGHS UP A FEW DEGREES. WITH AVIATION DISCUSSION
FOLLOWING AS WELL.
&&
.DISCUSSION...
TEMPERATURES CONTINUE TO RUN AT OR A LITTLE ABOVE WHERE THEY WERE
YESTERDAY AT ANY WEST CENTRAL TEXAS LOCATIONS. LATEST RUC
FORECASTING A LITTLE WARMER AS WELL. USED THE RUC AS A STARTING
POINT AND BOOSTED TEMPS.
&&
.AVIATION...
VFR CONDITIONS TO PREVAIL ACROSS WEST CENTRAL TEXAS TERMINALS WELL
INTO TONIGHT...AS DRY SOUTHWEST TO WEST WINDS PREVAIL. MODELS NOT
FORECASTING MUCH IN THE WAY OF STRATUS RETURN TUESDAY
MORNING...EVEN NEAR JUNCTION AND BRADY...KJCT AND KBBD. BUT BOTH
PERSISTENCE AND CLIMATOLOGY SUGGESTS THERE IS A DECENT CHANCE.
WILL LEAVE IT IN THE FORECAST FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 617 AM CDT MON APR 15 2013/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
MVFR STRATUS WAS APPROACHING KJCT AT 11Z...AS LOW LEVEL MOISTURE
RETURNED FROM THE EAST. STRATUS MAY ALSO AFFECT KBBD AFTER
13Z. STRATUS CIGS SHOULD SCATTER OUT BY MID MORNING AS LOW LEVEL
MOISTURE WAS SHALLOW. MVFR STRATUS WILL RETURN TONIGHT AT KJCT...
KBBD LATE TONIGHT. STRATUS MAY POSSIBLY AFFECT KSOA...BUT WILL NOT
INCLUDE AT THIS TIME AS CONFIDENCE IS LOWER FARTHER WEST.
PREV DISCUSSION... /ISSUED 420 AM CDT MON APR 15 2013/
SHORT TERM...
A WEAK COLD FRONT JUST NORTH OF HASKELL AND THROCKMORTON COUNTIES
THIS MORNING...IS INDICATED TO WASH OUT AND MOVE BACK NORTH WITH
SURFACE HEATING AND MIXING MIDDAY. LOW LEVEL MOISTURE WILL BE
RETURNING FROM THE EAST...AND A DRY LINE SHOULD SET UP THIS
AFTERNOON...FROM JUST EAST OF THROCKMORTON COUNTY TO CROSS PLAINS...
BRADY AND JUNCTION. WHILE THERE IS AN OUTSIDE CHANCE OF A
THUNDERSTORM DEVELOPING IN EASTERN THROCKMORTON COUNTY...ACTIVITY
SHOULD BE SPARSE IF IT OCCURS AND MOVE QUICKLY EAST.
TEMPERATURES TODAY WILL BE WARM...SIMILAR TO YESTERDAY...WITH
SOUTHWEST WINDS BRINGING IN DRY DESERT AIR TO THE WEST OF THE DRY
LINE. WINDS WILL BE WEAKER HOWEVER...KEEPING CONDITIONS BELOW RED
FLAG WARNING CRITERIA FOR FIRE WEATHER.
04
THE HEADLINE FOR THE LATTER PART OF THE SHORT TERM REMAINS
CENTERED ON RAIN CHANCES WITH THIS NEXT COLD FRONT. THE GFS AND
ECMWF ARE NOT IN VERY GOOD AGREEMENT REGARDING THE TIMING OF THE
FRONT WEDNESDAY NIGHT. SO...I DECIDED TO GO WITH A BLEND BETWEEN
WHAT WE HAD IN OUR WIND GRIDS FOR WEDNESDAY NIGHT AND A COMPROMISE
WITH THE GENERAL CONSENSUS FROM OUR NEIGHBORING OFFICES. AS FOR
RAIN CHANCES WEDNESDAY AND WEDNESDAY NIGHT...THE BEST CHANCES
STILL LOOK BEST FOR WEDNESDAY NIGHT. A SURFACE DRYLINE WILL MIX
EAST ACROSS OUR COUNTIES ON WEDNESDAY. THIS BOUNDARY AND THE COLD
FRONT MAY MERGE WEDNESDAY EVENING AND CREATE A FOCUS FOR
THUNDERSTORM DEVELOP. MY CONFIDENCE AS TO WHERE THESE TWO
BOUNDARIES MAY MERGE REMAINS LOW AT THIS TIME...MAINLY GIVEN THE
INCONSISTENCIES AMONG THE WIND FIELD OF THE THE MODELS. SO...I
DECIDED TO LEAVE THE POPS UNCHANGED FOR WEDNESDAY AND WEDNESDAY
NIGHT...EVEN THOUGH THE LATEST MEX MOS GUIDANCE IS PRESENTING 50
POPS FOR WEDNESDAY NIGHT FOR OUR THREE VERIFICATION LOCATIONS.
AS FOR TEMPERATURES FOR THE REMAINDER OF THE SHORT
TERM...AFTERNOON HIGHS TUESDAY WILL BE WELL ABOVE SEASONAL
NORMALS...WITH MUCH COOLER HIGHS FOR WEDNESDAY. THE LATEST MEX MOS
GUIDANCE PRESENTED NUMBERS FOR LOWS WEDNESDAY NIGHT MUCH WARMER
THAN WE HAD IN OUR PREVIOUS FORECAST PACKAGE. WITH MY CONFIDENCE
NOT VERY HIGH REGARDING THE TIMING OF THE FRONT WEDNESDAY
NIGHT...I DECIDED TO NOT INCREASE OUR LOWS FOR WEDNESDAY NIGHT
MORE THAN ONE DEGREE OVER WHAT WE HAD IN OUR PREVIOUS PACKAGE.
HUBER
LONG TERM...
THE LONG TERM...INTO NEXT SUNDAY...LOOKS DRY. COOLER TEMPERATURES
WILL PREVAIL THROUGH THE END OF THIS WEEK...BEFORE RETURN
SOUTHERLY LOW-LEVEL FLOW INITIATES A WARMING REBOUND FOR NEXT
WEEKEND. THE GFS DOES INDICATE THE POSSIBILITY OF ANOTHER COLD
FRONT NEXT SUNDAY. HOWEVER...I DECIDED NOT TO GO WITH THAT
SOLUTION THAT FAR IN ADVANCE. I WILL CONTINUE SOUTH SURFACE WINDS
FOR NEXT SUNDAY...WITH AFTERNOON HIGHS MAINLY IN THE 75 TO 80
RANGE.
HUBER
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED ACROSS MUCH OF WEST
CENTRAL TEXAS THIS AFTERNOON...AS A DRYLINE DEVELOPS FROM NEAR
BRECKENRIDGE TO CROSS PLAINS AND JUNCTION. THE DRYLINE WILL BE
FARTHER WEST TUESDAY AFTERNOON...GENERALLY ALONG AND WEST OF AN
OZONA TO SWEETWATER LINE. ON WEDNESDAY...THE DRYLINE SHOULD SET
UP FARTHER EAST...ALONG AND WEST OF A SONORA...SAN
ANGELO...ABILENE...HASKELL LINE. WHILE RH VALUES WILL FALL BELOW
20 PERCENT WEST OF THE DRYLINE...SOUTHWEST WINDS SHOULD REMAIN
BELOW 20 MPH...KEEPING CONDITIONS FROM BECOMING CRITICAL.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 96 63 90 67 87 / 10 10 10 10 30
SAN ANGELO 96 64 94 72 88 / 5 5 5 10 20
JUNCTION 97 64 91 71 89 / 5 5 5 10 20
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1043 PM CDT TUE APR 16 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
CENTERED OVER CENTRAL CANADA AND A RIDGE AXIS EXTENDING INTO THE
NORTHERN MISSISSIPPI VALLEY. A WEAK COLD FRONT IS EXTENDING ACROSS
LAKE SUPERIOR AND NORTHERN MINNESOTA...WHICH IS CONTRIBUTING TO THE
WIDESPREAD STRATO-CU FIELD OVER NORTHERN PARTS OF WISCONSIN. THIS
STRATO-CU FIELD HAS BEEN SLOWLY RETREATING NORTHWARD THIS
AFTERNOON...AND CLEARING SKIES ARE NOW APPROACHING WAUSAU AND
MARINETTE AT THIS HOUR. MEANWHILE...CONVECTION IS OCCURRING NORTH
OF A STATIONARY FRONT LOCATED ACROSS THE OHIO VALLEY. AS THIS FRONT
LIFTS NORTH TOMORROW...THE MAIN FORECAST CONCERN BECOMES TIMING OF
THE INCOMING PRECIPITATION.
TONIGHT...AS CONVERGENCE ALONG A REINFORCING COLD FRONT
WEAKENS...CANADIAN HIGH PRESSURE WILL FEED IN DRIER AIR...BROUGHT IN
BY LIGHT NE WINDS. MAY SEE SCT CLOUD COVER LINGER INTO THE EARLY
EVENING HOURS OVER N-C WISCONSIN BEFORE DRY AIR EVENTUALLY WINDS OUT
AND SKIES TURN MOSTLY CLEAR. IF AND WHEN THIS OCCURS...TEMPS WILL
HAVE POTENTIAL TO TANK OVER N-C WISCONSIN WHERE THERE REMAINS DEEP
SNOW PACK. HAVE DROPPED LOW TEMPS CONSIDERABLY. OTHERWISE...A WARM
FRONT WILL BE LIFTING NORTH ACROSS THE MID-MISSISSIPPI VALLEY...AND
MID CLOUDS WILL SPREAD NORTH OVER CENTRAL AND EAST-CENTRAL WISCONSIN
AFTER MIDNIGHT. THE DRY AIR FEED TO KEEP PRECIP WELL SOUTH OF THE
REGION THOUGH. LOWS RANGING FROM AROUND 20 DEGREES NORTH TO THE MID
30S SOUTH.
WEDNESDAY...THE WARM FRONT WILL CONTINUE TO GRADUALLY LIFT NORTH
OVER CENTRAL AND NORTHERN ILLINOIS. DRY NE FEED OF AIR WILL TRY TO
HOLD BACK PRECIP DURING THE MORNING...AND IT LOOKS LIKE MODELS HAVE
SLOWED THE NORTHERLY PROGRESS OF PRECIP CHANCES. WILL GO DRY WITH
THE FORECAST THROUGH 18Z. AFTER THAT TIME THOUGH...SOUTHWEST FLOW
WILL STRENGTHEN OVER THE FRONT...WHICH SHOULD LEAD TO PRECIP MOVING
INTO CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON. THE
PRECIP WILL BE FIGHTING THE DRY AIR...SO THINK THE HEAVIER RAIN WILL
NOT ARRIVE UNTIL WEDNESDAY NIGHT...AND FAR NE WISCONSIN MAY NOT SEE
A DROP UNTIL AFTER 00Z AS WELL. HIGH TEMPS WILL LIKELY OCCUR MIDDAY
OR EARLY AFTERNOON BEFORE CLOUDS THICKEN AND/OR PRECIP STARTS
FALLING. PTYPE LIKELY TO BE TRICKY OVER N-C WISCONSIN WHERE THERE
WILL BE A +4C WARM NOSE ABOVE SURFACE TEMPS NEAR FREEZING. PREVIOUS
SHIFT INCLUDED A RAIN/SLEET MIX...AND THAT LOOKS GOOD COMPARED TO
THE PROJECTED SURFACE WET BULB TEMPS. HIGHS IN THE LOW TO MID 40S.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
ACTIVE AND COMPLEX WEATHER SITUATION WITH POTENTIAL FOR A COUPLE
ROUNDS OF SIGNIFICANT PRECIPITATION FOR THE SECOND HALF OF THE
WORK WEEK. SIGNIFICANT TROUGH WILL GRADUALLY SWING INTO THE HIGH
PLAINS BY 12Z THURSDAY AND BECOME NEGATIVELY TILTED AND DEEPEN BY
FRIDAY AFTERNOON.
AS PREVIOUSLY ADVERTISED...STRONG 850 MB JET WILL DEVELOP OVER THE
PLAINS EARLY WEDNESDAY EVENING AND WILL BE THE DRIVING FORCE FOR
STRONG WAA/LIFT AND SIGNIFICANT MOISTURE TRANSPORT INTO THE WESTERN
GREAT LAKES WEDNESDAY NIGHT. LARGE AREA OF MODERATE TO HEAVY
PRECIPTATION IS FORECAST TO BREAKOUT FROM EASTERN NEBRASKA TO
SOUTHWEST WISCONSIN AND SPREAD NORTHEAST ACROSS THE FORECAST AREA
OVERNIGHT INTO EARLY THURSDAY. PRECIPITABLE WATER VALUES OVER THE
MISSISSIPPI VALLEY NORTHWARD INTO WISCONSIN EXPECTED TO BE WELL
ABOVE NORMAL FOR THIS TIME OF YEAR. COMBINATION OF STRONG
FORCING...ANOMALOUSLY HIGH PRECIPITABLE WATER WILL LEAD MODERATE TO
HEAVY RAINFALL. THE GENERAL CONCENSUS OF THE LATEST GUIDANCE SEEMS
TO BE FOCUSING THE MAXIMUM QPF OVER ABOUT THE SOUTHEAST THIRD OF THE
STATE. HELD ONTO THUNDER POTENTIAL...ESPECIALLY OVER THE FOX VALLEY
AS WELL WEDNESDAY NIGHT. CANADIAN MODEL WAS FURTHEST NORTH THAN THE
OTHER GUIDANCE DURING THIS PERIOD...THUS WAS DISCONTED. THE AREA OF
HEAVIEST RAINFALL SHOULD BE EAST OF THE FORECAST AREA BY AROUND NOON
THURSDAY. ACROSS THE NORTHWEST PORTION OF THE FOPRECAST
AREA...APPEARS BOUNDARY LAYER TEMPERATURES WILL BE VERY CLOSE TO
FREEZING...THUS STILL FEEL THERE IS POTENTIAL FOR SOME FREEZING
RAIN...MIXED WITH SLEET AND WET SNOW PARTICULARLY IN THE 06Z TO 12Z
PERIOD THURSDAY MORNING.
UPPER SYSTEM THEN BECOMES NEGATIVELY TILTED THURSDAY EVENING WITH
SURFACE WAVE RAPIDLY INTENSIFYING. PROBLEM IS THAT STILL MUCH
DESCREPANCY IN MODEL GUIDANCE WITH RESPECT TO THE RATE OF
DEEPENING AND MOVEMENT OF THE SURFACE LOW. THUS...HAD TO REAMIN
SOMEWHAT BROAD BRUSH ON QPF AMOUNTS ACROSS THE FORECAST AREA. IT
DOES APPEAR THAT BY EARLY FRIDAY MORNING ENOUGH COLD AIR WILL BE
DRAWN INTO THE SYSTEM TO TURN THE PRECIPITATION OVER TO SNOW. LATER
SHIFTS SHOULD BE ABLE GET A BETTER HANDLE ON THE SYSTEM EVOLUTION
AND ASSOCIATED PRECIPITATION TYPES.
GIVEN THE POTENTIAL FOR A COUPLE ROUNDS OF MODERATE TO HEAVY
RAINFALL...MELTING SNOW AND MANY RIVERS AT OR ABOVE FLOOD STAGE
ALREADY...AREAL FLOOD WATCH HAS BEEN ISSUED. SEE ASSOCIATED
HYDROLOGY DISCUSSION FOR DETAILS BELOW.
LOOKS LIKE QUIETER AND DRIER CONDITIONS TO RETURN OVER THE
UPCOMING WEEKEND...ALTHOUGH TEMPERATUES WILL REMAIN WELL BELOW
NORMAL INTO EARLY NEXT WEEK.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1036 PM CDT TUE APR 16 2013
MID-LEVEL CLOUDS SHOULD LIFT NORTH ACROSS THE FORECAST AREA LATE
TONIGHT INTO EARLY WEDNESDAY...WITH CIGS GRADUALLY LOWERING DURING
THE DAY. LOW PRESSURE WILL BRING MODERATE RAIN TO THE AREA WEDNESDAY
AFTERNOON AND EVENING...WITH A MIX OF LIGHT SNOW/SLEET/RAIN POSSIBLE
OVER NORTH CENTRAL WI DURING THE LATE AFTERNOON AND EARLY EVENING.
CANNOT RULE OUT THE POSSIBILITY OF A BRIEF PERIOD OF FREEZING RAIN
AT RHI...BUT SFC TEMPS MAY STAY JUST ABOVE FREEZING. CIGS WILL
LOWER TO MVFR ONCE THE PCPN BEGINS...THEN DROP TO IFR AT MOST
LOCATIONS BY EVENING.
INSTABILITY WILL INCREASE DURING THE EVENING...SO ADDED A PROB30
FOR TSTMS AT ALL OF THE TAF SITES. LLWS IS ALSO EXPECTED TO
INCREASE BY SUNSET.
&&
.HYDROLOGY...
ISSUED AT 308 PM CDT TUE APR 16 2013
POTENTIAL OF FLOODING ON THE INCREASE THIS WEEK WITH EVEN LONG
TERM ISSUES THROUGH APRIL.
A STRENGTHENING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST TOWARD THE
GREAT LAKES REGION THROUGH FRIDAY. GULF MOISTURE WILL WORK
NORTHWARD TO PRODUCE WELL ABOVE NORMAL PRECIPITABLE WATER AMOUNTS
FOR THIS TIME OF THE YEAR. RIVERS OVER MUCH OF CENTRAL AND EAST
CENTRAL WISCONSIN ALREADY RUNNING HIGH. ADDITIONAL OR LINGERING
SNOW MELT WILL BE AVAILABLE OVER CENTRAL WISCONSIN RIVERS WHILE
AREAS WITH LITTLE SNOW LEFT...THE GROUND IS SATURATED ALONG WITH A
DEPARTING FROST TO PRODUCE ABOVE NORMAL RUN OFF. CONSENSUS OF
AVAILABLE MODEL RUNS FOR A TOTAL RAINFALL AMOUNT FROM LATE
WEDNESDAY AFTERNOON THROUGH FRIDAY MORNING INDICATE AROUND 2
INCHES OF RAIN SOUTHEAST OF A LINE FROM GREEN BAY TO WAUTOMA...AND
UP TO 1.5 INCHES NORTHWARD. THE RAIN WILL BE FOCUSED ALONG OR NEAR
A SOUTHWEST TO NORTHEAST BOUNDARY EXTENDING OVER SOUTHEAST
WISCONSIN. ANY THUNDERSTORMS WHICH CAN DEVELOP...WILL LIKELY
INCREASE THE RAINFALL TOTALS. NORTH CENTRAL WISCONSIN COULD SEE A
RAIN TO SNOW MIX BY FRIDAY FOR LESSER RAINFALL BUT ADDITIONAL
SNOWFALL TO THE PERSISTENT SNOW PACK. WILL ISSUE A FFA AREAL FLOOD
WARNING FOR CENTRAL AND EAST CENTRAL WISCONSIN THROUGH FRIDAY.
WILL CONSIDER AN ESF NORTH. THE AREAL FLOOD WARNING WILL LIKE
TRANSITION TO RIVER FLOOD WARNINGS BY THIS WEEKEND.
FOR A LONGER TERM FLOODING ISSUE DEVELOPING...THE INCREASING FLOWS
ON THE FOX AND WOLF RIVERS COMING INTO LAKE WINNEBAGO WILL
EVENTUALLY CAUSE THE LAKE TO RISE AND REMAIN FAIRLY HIGH FOR MUCH
OF APRIL IF PERIODS OF RAIN CONTINUE. THE COMBINATION OF STRONG
WINDS WITH HIGHER THAN NORMAL LAKE WINNEBAGO LAKE LEVELS WILL
INCREASE THE POTENTIAL OF SHORELINE FLOODING. HIGH LAKE WINNEBAGO
LEVELS WILL LIKELY TEND TO PRODUCE LONG TERM HIGH LEVELS UPSTREAM
ON THE WOLF AND FOX RIVERS THROUGH APRIL...AGAIN DEPENDING ON
ADDITIONAL RAINFALL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY MORNING FOR
WIZ020>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......ESB
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
638 PM CDT TUE APR 16 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
CENTERED OVER CENTRAL CANADA AND A RIDGE AXIS EXTENDING INTO THE
NORTHERN MISSISSIPPI VALLEY. A WEAK COLD FRONT IS EXTENDING ACROSS
LAKE SUPERIOR AND NORTHERN MINNESOTA...WHICH IS CONTRIBUTING TO THE
WIDESPREAD STRATO-CU FIELD OVER NORTHERN PARTS OF WISCONSIN. THIS
STRATO-CU FIELD HAS BEEN SLOWLY RETREATING NORTHWARD THIS
AFTERNOON...AND CLEARING SKIES ARE NOW APPROACHING WAUSAU AND
MARINETTE AT THIS HOUR. MEANWHILE...CONVECTION IS OCCURRING NORTH
OF A STATIONARY FRONT LOCATED ACROSS THE OHIO VALLEY. AS THIS FRONT
LIFTS NORTH TOMORROW...THE MAIN FORECAST CONCERN BECOMES TIMING OF
THE INCOMING PRECIPITATION.
TONIGHT...AS CONVERGENCE ALONG A REINFORCING COLD FRONT
WEAKENS...CANADIAN HIGH PRESSURE WILL FEED IN DRIER AIR...BROUGHT IN
BY LIGHT NE WINDS. MAY SEE SCT CLOUD COVER LINGER INTO THE EARLY
EVENING HOURS OVER N-C WISCONSIN BEFORE DRY AIR EVENTUALLY WINDS OUT
AND SKIES TURN MOSTLY CLEAR. IF AND WHEN THIS OCCURS...TEMPS WILL
HAVE POTENTIAL TO TANK OVER N-C WISCONSIN WHERE THERE REMAINS DEEP
SNOW PACK. HAVE DROPPED LOW TEMPS CONSIDERABLY. OTHERWISE...A WARM
FRONT WILL BE LIFTING NORTH ACROSS THE MID-MISSISSIPPI VALLEY...AND
MID CLOUDS WILL SPREAD NORTH OVER CENTRAL AND EAST-CENTRAL WISCONSIN
AFTER MIDNIGHT. THE DRY AIR FEED TO KEEP PRECIP WELL SOUTH OF THE
REGION THOUGH. LOWS RANGING FROM AROUND 20 DEGREES NORTH TO THE MID
30S SOUTH.
WEDNESDAY...THE WARM FRONT WILL CONTINUE TO GRADUALLY LIFT NORTH
OVER CENTRAL AND NORTHERN ILLINOIS. DRY NE FEED OF AIR WILL TRY TO
HOLD BACK PRECIP DURING THE MORNING...AND IT LOOKS LIKE MODELS HAVE
SLOWED THE NORTHERLY PROGRESS OF PRECIP CHANCES. WILL GO DRY WITH
THE FORECAST THROUGH 18Z. AFTER THAT TIME THOUGH...SOUTHWEST FLOW
WILL STRENGTHEN OVER THE FRONT...WHICH SHOULD LEAD TO PRECIP MOVING
INTO CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON. THE
PRECIP WILL BE FIGHTING THE DRY AIR...SO THINK THE HEAVIER RAIN WILL
NOT ARRIVE UNTIL WEDNESDAY NIGHT...AND FAR NE WISCONSIN MAY NOT SEE
A DROP UNTIL AFTER 00Z AS WELL. HIGH TEMPS WILL LIKELY OCCUR MIDDAY
OR EARLY AFTERNOON BEFORE CLOUDS THICKEN AND/OR PRECIP STARTS
FALLING. PTYPE LIKELY TO BE TRICKY OVER N-C WISCONSIN WHERE THERE
WILL BE A +4C WARM NOSE ABOVE SURFACE TEMPS NEAR FREEZING. PREVIOUS
SHIFT INCLUDED A RAIN/SLEET MIX...AND THAT LOOKS GOOD COMPARED TO
THE PROJECTED SURFACE WET BULB TEMPS. HIGHS IN THE LOW TO MID 40S.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
ACTIVE AND COMPLEX WEATHER SITUATION WITH POTENTIAL FOR A COUPLE
ROUNDS OF SIGNIFICANT PRECIPITATION FOR THE SECOND HALF OF THE
WORK WEEK. SIGNIFICANT TROUGH WILL GRADUALLY SWING INTO THE HIGH
PLAINS BY 12Z THURSDAY AND BECOME NEGATIVELY TILTED AND DEEPEN BY
FRIDAY AFTERNOON.
AS PREVIOUSLY ADVERTISED...STRONG 850 MB JET WILL DEVELOP OVER THE
PLAINS EARLY WEDNESDAY EVENING AND WILL BE THE DRIVING FORCE FOR
STRONG WAA/LIFT AND SIGNIFICANT MOISTURE TRANSPORT INTO THE WESTERN
GREAT LAKES WEDNESDAY NIGHT. LARGE AREA OF MODERATE TO HEAVY
PRECIPTATION IS FORECAST TO BREAKOUT FROM EASTERN NEBRASKA TO
SOUTHWEST WISCONSIN AND SPREAD NORTHEAST ACROSS THE FORECAST AREA
OVERNIGHT INTO EARLY THURSDAY. PRECIPITABLE WATER VALUES OVER THE
MISSISSIPPI VALLEY NORTHWARD INTO WISCONSIN EXPECTED TO BE WELL
ABOVE NORMAL FOR THIS TIME OF YEAR. COMBINATION OF STRONG
FORCING...ANOMALOUSLY HIGH PRECIPITABLE WATER WILL LEAD MODERATE TO
HEAVY RAINFALL. THE GENERAL CONCENSUS OF THE LATEST GUIDANCE SEEMS
TO BE FOCUSING THE MAXIMUM QPF OVER ABOUT THE SOUTHEAST THIRD OF THE
STATE. HELD ONTO THUNDER POTENTIAL...ESPECIALLY OVER THE FOX VALLEY
AS WELL WEDNESDAY NIGHT. CANADIAN MODEL WAS FURTHEST NORTH THAN THE
OTHER GUIDANCE DURING THIS PERIOD...THUS WAS DISCONTED. THE AREA OF
HEAVIEST RAINFALL SHOULD BE EAST OF THE FORECAST AREA BY AROUND NOON
THURSDAY. ACROSS THE NORTHWEST PORTION OF THE FOPRECAST
AREA...APPEARS BOUNDARY LAYER TEMPERATURES WILL BE VERY CLOSE TO
FREEZING...THUS STILL FEEL THERE IS POTENTIAL FOR SOME FREEZING
RAIN...MIXED WITH SLEET AND WET SNOW PARTICULARLY IN THE 06Z TO 12Z
PERIOD THURSDAY MORNING.
UPPER SYSTEM THEN BECOMES NEGATIVELY TILTED THURSDAY EVENING WITH
SURFACE WAVE RAPIDLY INTENSIFYING. PROBLEM IS THAT STILL MUCH
DESCREPANCY IN MODEL GUIDANCE WITH RESPECT TO THE RATE OF
DEEPENING AND MOVEMENT OF THE SURFACE LOW. THUS...HAD TO REAMIN
SOMEWHAT BROAD BRUSH ON QPF AMOUNTS ACROSS THE FORECAST AREA. IT
DOES APPEAR THAT BY EARLY FRIDAY MORNING ENOUGH COLD AIR WILL BE
DRAWN INTO THE SYSTEM TO TURN THE PRECIPITATION OVER TO SNOW. LATER
SHIFTS SHOULD BE ABLE GET A BETTER HANDLE ON THE SYSTEM EVOLUTION
AND ASSOCIATED PRECIPITATION TYPES.
GIVEN THE POTENTIAL FOR A COUPLE ROUNDS OF MODERATE TO HEAVY
RAINFALL...MELTING SNOW AND MANY RIVERS AT OR ABOVE FLOOD STAGE
ALREADY...AREAL FLOOD WATCH HAS BEEN ISSUED. SEE ASSOCIATED
HYDROLOGY DISCUSSION FOR DETAILS BELOW.
LOOKS LIKE QUIETER AND DRIER CONDITIONS TO RETURN OVER THE
UPCOMING WEEKEND...ALTHOUGH TEMPERATUES WILL REMAIN WELL BELOW
NORMAL INTO EARLY NEXT WEEK.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 630 PM CDT TUE APR 16 2013
STRATOCUMULUS OVER NORTHERN WI WAS DISSIPATING EARLY THIS EVG...SO
EXPECT SKIES TO CLEAR THERE SHORTLY AFTER SUNSET. MID-LEVEL
CLOUDS WERE LIFTING NORTH THROUGH SOUTHERN WI...AND SHOULD REACH
CENTRAL WI BY LATE EVG...AND FAR NORTHERN WI TOWARD DAYBREAK ON
WEDNESDAY. LOW PRESSURE WILL BRING SOME LIGHT RAIN TO THE AREA
WEDS AFTERNOON...WITH A MIX OF LIGHT RAIN/SLEET POSSIBLE OVER
NORTH CENTRAL WI LATE IN THE DAY. VFR CONDITIONS ARE EXPECTED
UNTIL THE PCPN ARRIVES...WITH MVFR CIGS/VSBYS ACCOMPANYING THE
STEADIER PCPN DURING THE MID TO LATE AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 308 PM CDT TUE APR 16 2013
POTENTIAL OF FLOODING ON THE INCREASE THIS WEEK WITH EVEN LONG
TERM ISSUES THROUGH APRIL.
A STRENGTHENING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST TOWARD THE
GREAT LAKES REGION THROUGH FRIDAY. GULF MOISTURE WILL WORK
NORTHWARD TO PRODUCE WELL ABOVE NORMAL PRECIPITABLE WATER AMOUNTS
FOR THIS TIME OF THE YEAR. RIVERS OVER MUCH OF CENTRAL AND EAST
CENTRAL WISCONSIN ALREADY RUNNING HIGH. ADDITIONAL OR LINGERING
SNOW MELT WILL BE AVAILABLE OVER CENTRAL WISCONSIN RIVERS WHILE
AREAS WITH LITTLE SNOW LEFT...THE GROUND IS SATURATED ALONG WITH A
DEPARTING FROST TO PRODUCE ABOVE NORMAL RUN OFF. CONSENSUS OF
AVAILABLE MODEL RUNS FOR A TOTAL RAINFALL AMOUNT FROM LATE
WEDNESDAY AFTERNOON THROUGH FRIDAY MORNING INDICATE AROUND 2
INCHES OF RAIN SOUTHEAST OF A LINE FROM GREEN BAY TO WAUTOMA...AND
UP TO 1.5 INCHES NORTHWARD. THE RAIN WILL BE FOCUSED ALONG OR NEAR
A SOUTHWEST TO NORTHEAST BOUNDARY EXTENDING OVER SOUTHEAST
WISCONSIN. ANY THUNDERSTORMS WHICH CAN DEVELOP...WILL LIKELY
INCREASE THE RAINFALL TOTALS. NORTH CENTRAL WISCONSIN COULD SEE A
RAIN TO SNOW MIX BY FRIDAY FOR LESSER RAINFALL BUT ADDITIONAL
SNOWFALL TO THE PERSISTENT SNOW PACK. WILL ISSUE A FFA AREAL FLOOD
WARNING FOR CENTRAL AND EAST CENTRAL WISCONSIN THROUGH FRIDAY.
WILL CONSIDER AN ESF NORTH. THE AREAL FLOOD WARNING WILL LIKE
TRANSITION TO RIVER FLOOD WARNINGS BY THIS WEEKEND.
FOR A LONGER TERM FLOODING ISSUE DEVELOPING...THE INCREASING FLOWS
ON THE FOX AND WOLF RIVERS COMING INTO LAKE WINNEBAGO WILL
EVENTUALLY CAUSE THE LAKE TO RISE AND REMAIN FAIRLY HIGH FOR MUCH
OF APRIL IF PERIODS OF RAIN CONTINUE. THE COMBINATION OF STRONG
WINDS WITH HIGHER THAN NORMAL LAKE WINNEBAGO LAKE LEVELS WILL
INCREASE THE POTENTIAL OF SHORELINE FLOODING. HIGH LAKE WINNEBAGO
LEVELS WILL LIKELY TEND TO PRODUCE LONG TERM HIGH LEVELS UPSTREAM
ON THE WOLF AND FOX RIVERS THROUGH APRIL...AGAIN DEPENDING ON
ADDITIONAL RAINFALL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY MORNING FOR
WIZ020>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......ESB
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
342 PM CDT MON APR 15 2013
.VERY SHORT TERM...TONIGHT AND TUESDAY.
TONIGHT - CONFIDENCE...MEDIUM
PER WATER VAPOR STRONG SOUTHWEST UPPER JET ROUNDING BASE OF TROUGH
NRN MN CIRCULATION CENTER. MODELS ALSO SHOWING DECENT 850/700
MILLIBAR FRONTOGENETICAL FORCING ACROSS PORTIONS OF SRN WI. RAIN
AREA ALREADY WORKING INTO SRN WI. EXPECTED TO AFFECT MUCH SRN WI
INTO THE EVENING HOURS. COMBO OF HRRR AND SPC WRF SUGGESTS BULK OF
PRECIP WILL BE AFFECTING SE 1/2 OF THE CWA DURING THE EVENING HOURS.
TUESDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE GRADUALLY BUILDS IN. MODELS HAVE TRENDED THE QPF
FURTHER SOUTH. 12Z ECMWF DOES HAVE LIGHT QPF IN THE FAR SOUTH DURING
THE AFTERNOON SO HAVE RETAINED A SMALL POP BUT CONFIDENCE NOT GREAT.
THERE IS AN INDICATION OF AN INVERTED TROUGH AND POSSIBLY SOME RIGHT
REAR DIVERGENCE OF JET CORE TO OUR NORTH. SOUNDINGS SHOW LOW LEVELS
BELOW 5K FEET DRY BUT MID LEVEL SATURATION WITH OMEGA WITH SOME
PROGGD FRONTOGENETICAL FORCING IN THE 700-500 MILLIBAR LAYER.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
12Z NAM BRINGS QPF INTO THE FORECAST AREA WITH ISENTROPIC
LIFT/850-700 MB FRONTOGENESIS/850 MB CONVERGENCE AS IT LIFTS 850/700
MB BAROCLINIC ZONES FARTHER NORTH THAN OTHER MODELS. 12Z ECMWF
BRINGS THE PCPN IN TUESDAY AFTERNOON THEN EAST IN THE EVENING...BUT
THE 850MB CONVERGENCE IS BETTER AFTER 06Z WEDNESDAY. IN SPITE OF
RELATIVELY DRY EAST FLOW...WILL KEEP CHANCE POPS IN THE FAR
SOUTH.
WEDNESDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM TO
HIGH.
ELONGATED TROUGH OF SURFACE LOW PRESSURE...WITH MODELS SHOWING TWO
DISTINCT CENTERS...WILL LIFT INTO THE REGION AHEAD OF DEEP LONG WAVE
TROUGH AND THEN CONSOLIDATE OVER THE WESTERN GREAT LAKES. COPIOUS
AMOUNTS OF MOISTURE STREAMING INTO THE REGION WILL PRODUCE PERIODS
OF MODERATE TO HEAVY RAIN.
SOME TRACK LOCATION DIFFERENCES THAT IMPACT THE AMOUNT OF
INSTABILITY AND AREAL EXTENT OF THUNDERSTORMS...BUT CONSENSUS
FORECAST QPF OF 1.6 TO NEARLY 3 INCHES OF RAIN LOOKS TO OCCUR WITH
ONLY ISOLATED THUNDERSTORMS...WITH HIGHER AMOUNTS IF THUNDER BECOMES
MORE WIDESPREAD. HAVE ISSUED AN ESF TO HIGHLIGHT RISK OF INCREASED
FLOODING ACROSS THE REGION...WITH SATURATED GROUND UNABLE TO HOLD
MUCH ADDITIONAL RAINFALL AND MANY RIVERS ALREADY IN OR NEAR
FLOOD.
COLDER AIR WRAPPING IN BEHIND THE LOW WILL BRING A MIX OF RAIN AND
SNOW AFTER MIDNIGHT THURSDAY NIGHT...WITH ALL SNOW EXPECTED
NORTHWEST OF MADISON BY 12Z FRIDAY. BETTER DEFORMATION TO THE
NORTHWEST OF THE FORECAST AREA AND LIGHT QPF AMOUNTS AS TEMPERATURES
COOL SO ONLY MINOR ACCUMULATIONS EXPECTED.
NOT MUCH OF A CHANGE IN TEMPERATURES BETWEEN HIGHS WEDNESDAY AND
OVERNIGHT LOWS WITH EXPECTED NON-DIURNAL TREND. HIGHS NEAR 60 IN THE
FAR SE...THOUGH WARMER GFS MOS GUIDANCE IS PUSHING NEAR 70 IN THE
SOUTH.
.LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE LOW TO
MEDIUM.
KEEPING CHANCE POPS FOR FRIDAY AS REGION REMAINS UNDER THE CYCLONIC
FLOW OF 500 MB TROUGH OVER THE CENTRAL U.S. AT START OF THE
PERIOD...WITH DRY WEATHER FROM OVERNIGHT FRIDAY THROUGH SATURDAY
NIGHT IN NW FLOW AS THE TROUGH SLOWLY PUSHES EAST. ANOTHER
WAVE COMES ASHORE IN THE PACIFIC NW FRIDAY AFTERNOON...REACHING THE
CENTRAL/SRN PLAINS BY SUNDAY MORNING....WHILE ANOTHER WAVE TRACKS
ALONG THE US/CANADIAN BORDER RIGHT BEHIND. THIS BRINGS THE CHANCE
FOR WET WEATHER BACK INTO THE FORECAST SUNDAY THROUGH THE REST OF
THE EXTENDED. BELOW NORMAL TEMPS FRIDAY AND SATURDAY WARM TO NEAR
NORMAL LEVELS SUNDAY AND MONDAY.
&&
.AVIATION/00Z TAFS/...UPPER JET AND LOWER LEVEL FRONTOGENETICALLY
INDUCED AREA OF RAIN TO MOVE THROUGH SOUTHERN WI THIS EVENING. MVFR
CEILINGS/VSBYS POSSIBLE. SOUNDINGS SHOW INITIALLY DRY LAYER IN THE
LOW LEVELS...THIS PROGGD TO MOISTEN UP. WILL GO WITH A MID DECK FOR
TUESDAY WITH LOWER LEVELS FAIRLY DRY. AFTERNOON SHOWERS POSSIBLE IN
FAR SRN WI BUT CONFIDENCE TOO LOW FOR INCLUSION IN TAFS.
&&
.MARINE...SOUTHWEST WINDS STILL GUSTING OVER CRITERIA SO WILL RETAIN
HEADLINE THROUGH 7 PM EXPIRATION. GRADIENT SLACKENS UP TONIGHT. HIGH
GRADUALLY BUILDS IN TUESDAY. WINDS GO NORTHEAST BUT NOT HIGH ENOUGH
TO WARRANT SMALL CRAFT CONCERNS AT THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 AM CDT MON APR 15 2013
.SHORT TERM...
712 PM CDT SUN APR 14 2013
WARM FRONT IS MAKING NORTHWARD PROGRESS ACROSS THE SOUTHERN
PORTIONS OF THE FORECAST AREA EARLY THIS EVENING. TEMPERATURES
WARMED INTO THE LOWER 40S AS FAR NORTH AS KAUM-KFKA-KY51-KDLL
THROUGH 00Z. READINGS HAD SURGED INTO THE LOWER 60S OVER THE FAR
SOUTHERN PART OF THE FORECAST AREA...BUT NOW THAT THE SUN IS
SETTING EXPECT THAT TO FALL BACK. MEANWHILE THE COLD FRONT WAS
MAKING EASTWARD PROGRESS ACROSS CENTRAL IA AS THE SECONDARY LOW
ALONG THE MN/IA BORDER MOVED NORTHEAST. FINALLY...FURTHER NORTH
THE REGION REMAINS LOCKED INTO THE COOL AIR AND MIXED
PRECIPITATION. FROM REPORTS RECEIVED IN WESTERN AND NORTH CENTRAL
WI...OPTED TO EXTEND THE ADVISORY THROUGH 06Z...AND PRECIPITATION
WILL CONTINUE AND TEMPERATURES WILL LIKELY NOT BUDGE.
SHORT TERM MESOSCALE MODELS ARE HANDLING THE SITUATION REASONABLY
WELL...AND HAVE FOLLOWED THE HRRR AND ARXLAPS MODEL RUNS FOR
UPDATES THIS EVENING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CDT SUN APR 14 2013
UPPER LEVEL RIDGING TRANSITIONS OVER THE UPPER MISSISSIPPI RIVER
VALLEY WITH THE EXIT OF THE LOW PRESSURE SYSTEM. THE 14.12Z GFS/NAM
WOULD BRING PIECES OF UPPER LEVEL ENERGY ACROSS THE TOP OF THE
RIDGE...WHILE OVER IA/NORTHERN ILL THEY BOTH SUGGEST AN AREA OF LOW
LEVEL WARM AIR ADVECTION/ISENTROPIC UPGLIDE/SLOPING FRONTOGENETIC
LIFT. BOTH AREAS COULD HAVE ENOUGH FORCING FOR LIGHT PCPN
PRODUCTION...AND THIS IS REFLECTED IN THE GFS/NAM QPF FIELDS. BETTER
CHANCES WOULD BE TO THE SOUTH. HOWEVER...SATURATION LOOKS TO BE AN
ISSUE. NORTH-SOUTH RUNNING X-SECTIONS AND BUFKIT SOUNDINGS SHOW AN
INCREASE IN MOISTURE FROM THE SOUTH...MOSTLY CONFINED AROUND 700
MB...WITH A RELATIVELY DRY ATMOSPHERE SUB 850 MB. THINK THERE WILL
BE ENOUGH LIFT TO WORK WITH THE AVAILABLE SATURATION TO GET THROUGH
THAT DAY LAYER...MOSTLY AS SPRINKLES TO LIGHT SHOWERS. ACCUMULATIONS
LOOK MINIMAL AT THE MOMENT...WITH CHANCES CONFINED TO PARTS OF
NORTHEAST IA/SOUTHWEST WI.
STORM SYSTEM STILL SLATED TO IMPACT THE AREA IN THE WED NIGHT/THU
TIME FRAME...WITH THE GFS/ECMWF BRINGING A SFC LOW FROM THE SOUTHERN
PLAINS TO ACROSS NORTHERN ILL BY 06Z THU. THE GEM IS A BIT FARTHER
NORTH...BUT HAS SIMILAR TIMING. CURRENT TRACK WOULD ALLOW FOR THE
SYSTEM TO BRING A GOOD AMOUNT OF LOW LEVEL WARM AIR
NORTHWARD...WHICH WOULD RESULT IN MAINLY RAIN FOR THE LOCAL FORECAST
AREA...AND THE SYSTEM/S DEFORMATION SNOW BAND LAYING UP ACROSS
NORTHERN MN. THAT SAID...THE MODELS HAVE BEEN JUMPING AROUND QUITE A
BIT...SO CONFIDENCE IS SHAKY IN JUST HOW THIS WILL PLAY OUT. CHANCES
FOR PCPN LOOK FAIRLY HIGH...EVEN LIKELY...BUT JUST WHAT WILL FALL
AND HOW MUCH IS STILL UNCERTAIN. CAN/T RULE OUT ANOTHER SHOT FOR
LATE SEASON SNOW.
CYCLONIC FLOW POST THIS STORM SYSTEM COULD KEEP SOME SMALL PCPN
CHANCES LINGERING INTO NEXT WEEKEND. THERE WILL ALSO BE ANOTHER SHOT
OF UNSEASONABLY COLD AIR. HIGHS WILL BE STUCK IN THE 40S
THU-FRI...WITH BELOW FREEZING LOWS.
&&
.AVIATION...THROUGH 06Z TUESDAY
1157 PM CDT SUN APR 14 2013
RAIN AND ASSOCIATED REDUCTION IN VISIBILITY HAS MOVED EAST OF THE
TAF SITES AS OF 1130 PM. LOW CLOUDS HAVE CLEARED KRST AND WILL
CLEAR KLSE SHORTLY. IMPROVING TREND WILL CONTINUE THROUGH THE
NIGHT. WITH ALL OF THE MOISTURE...SOME THOUGHT FOR FOG POSSIBILITY...
BUT WITH INCREASING WEST WIND AND INFLUX OF DRIER AIR FEEL IT WILL
NOT BE AN ISSUE. WINDS WILL BE KICKING UP FROM THE WEST-SOUTHWEST
AS THE LOW WRAPS UP. SOME GUSTS UP IN THE 20-30 KT RANGE
POSSIBLE...ESPECIALLY ACROSS THE HIGHER TERRAIN...AFFECTING KRST.
&&
.HYDROLOGY...THIS WEEK
ISSUED AT 310 PM CDT SAT APR 12 2013
THE CURRENT PRECIPITATION EVENT IS STILL ON TRACK TO PRODUCE BETWEEN
1 AND 1.5 INCHES OF LIQUID ACROSS MUCH OF THE REGION. THE SLOWER
PROGRESSION OF THE STORM SYSTEM WILL SHIFT THE AXIS OF HEAVIER
RAINFALL A BIT WESTWARD...NOW MORE ALONG AND EAST OF THE MISSISSIPPI
RIVER. LATER THIS EVENING AS THE COLD FRONT CROSSES...CONVECTION
COULD LEAD TO ISOLATED HIGHER RAINFALL AMOUNTS WITH SOME 2.0 INCH
TOTALS POSSIBLE. REGARDLESS...THE FORECAST QPF BRINGS ANOTHER ROUND
OF SIGNIFICANT RISES ON THE BLACK AND KICKAPOO RIVER BASINS TO JUST
SHY OF FLOOD STAGE. ON THE TREMPEALEAU RIVER AT DODGE...A
CONTINUATION OF MINOR FLOODING IS EXPECTED. OTHER TRIBUTARIES ACROSS
SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WESTERN WISCONSIN WILL
SEE WITHIN-BANKFULL RISES OVER THE NEXT FEW DAYS. THE CAVEAT IS IF
OBSERVED RAINFALL TONIGHT IS MUCH HIGHER THAN FORECAST...THEN FLOOD
WARNINGS WOULD BE NEEDED FOR A FEW SITES ON THE KICKAPOO AND
BLACK...SO THOSE WITH INTERESTS ON AREA RIVERS SHOULD STAY TUNED TO
THE LATEST RIVER STATEMENTS AND FORECASTS.
THE MAIN STEM OF THE MISSISSIPPI RIVER WILL REMAIN NEARLY STEADY OR
SEE A GRADUAL UPTICK THIS WEEK AS RAIN AND SNOWMELT TODAY/TONIGHT
WORKS ITS WAY DOWNSTREAM. THE ONLY EXCEPTION IS AT MCGREGOR
IOWA...WHERE THE RIVER LEVEL RISES ENOUGH SUCH THAT BY WEDNESDAY
NIGHT INTO THURSDAY IT APPROACHES FLOOD STAGE.
LOOKING AHEAD...ANOTHER SYSTEM SYSTEM LOOKS TO IMPACT THE ENTIRE
REGION WEDNESDAY NIGHT AND THURSDAY. CURRENT HPC DAY 4-5 QPF POINTS
TO ANYWHERE FROM 3/4 TO 1.5 INCHES OF LIQUID. THESE AMOUNTS
CERTAINLY WOULD INITIATE SOME AND/OR PROLONG FLOODING CONCERNS
ACROSS THE REGION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
712 PM CDT SUN APR 14 2013
WI...WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...MW
LONG TERM....RIECK
AVIATION...MW
HYDROLOGY....ZT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1128 PM CDT SUN APR 14 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 813 PM CDT SUN APR 14 2013
MAIN AREA OF PCPN WAS OCCURRING ACROSS NC WI EARLY THIS EVG...WITH
DRY CONDITIONS FARTHER SE...INCLUDING THE FOX VALLEY AND LKSHR AREAS.
WARM AIR ALOFT HAD CHANGED THE SNOW TO FREEZING RAIN OVER NC WI...
WHERE SFC TEMPS WERE STILL AT OR SLIGHTLY BLO FREEZING. SFC WET BULB
TEMPS REMAINED BLO FREEZING OVER NC/FAR NE WI...AND MODEL FCSTS SHOW
THIS CONTINUING OVER FAR NORTHERN WI UNTIL AT LEAST 06Z. GIVEN THIS...
PLUS SEVERAL REPORTS OF ICING AND ONE REPORT OF CARS IN DITCHES...
HAVE OPTED TO ISSUE A FREEZING RAIN ADVISORY FOR THE NEXT 5 HOURS
OR SO.
RAIN WILL FILL IN ACROSS THE SE HALF OF THE CWA LATE THIS EVG AND
EARLY MONDAY MORNING...AS THE OCCLUDED FRONT MOVES THROUGH. ONCE
THE FRONT PASSES THROUGH...PCPN SHOULD DECREASE RAPIDLY. ALTHOUGH
TSTMS OVER N IA HAVE DISSIPATED...DECIDED TO KEEP A CHANCE OF THUNDER
IN C/EC WI DURING THE LATE EVG/EARLY MONDAY MORNING PERIOD...AS BEST
LI`S DROP TO ZERO TO -1 C.
HOURLY POP/WX GRIDS HAVE BEEN UPDATED TO MATCH EXPECTED TRENDS FOR
THE REST OF THE NIGHT.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ELONGATED LOW
PRESSURE SPINNING ALONG THE IOWA/NEBRASKA BORDER THIS
AFTERNOON...AND A SURFACE WARM FRONT EXTENDING EASTWARD ACROSS
NORTHERN ILLINOIS. SOUTH OF THE WARM FRONT...TEMPERATURES ARE IN
THE 60S AND 70S. BUT NORTH OF THE FRONT...A 50KT SSW LLJ IS LEADING TO
A BAND OF PRECIPITATION WHICH IS NOW PUSHING INTO THE NORTHERN
SECTIONS OF THE BADGER STATE. TEMPERATURES REMAIN IN THE 20S AND
30S WITHIN THIS BAND OF PRECIP...WHERE LOCATIONS OVER CENTRAL
WISCONSIN HAVE PICKED UP A QUICK 2-3 INCHES OF WET SNOW. A FEW
SPOTTER REPORTS HAVE CONFIRMED WHAT DUAL POL IS SHOWING...THAT SNOW
IS MIXING WITH RAIN AND SLEET...WITH THE CHANGE OVER NOW SPREADING
INTO SOUTHERN MARATHON AND SHAWANO COUNTIES. ADDITIONALLY...SURFACE
WET BULB ZERO TEMPS ARE SPREADING NORTHEAST INTO EAST-CENTRAL
WISCONSIN...SO SHOULDNT SEE TOO MUCH MORE ACCUMS IN THESE AREAS.
STILL EXPECTING THE MODERATE TO HEAVY SNOW TO SPREAD INTO
NORTH-CENTRAL WISCONSIN THIS AFTERNOON WHERE A QUICK 3 INCHES WILL
LIKELY FALL. WILL CONTINUE TO HANDLE THE SNOWFALL WITH SPS
UPDATES. PRECIP CONTINUES TO BE THE MAIN FORECAST CONCERN FOR THIS
FORECAST.
TONIGHT...LOW PRESSURE WILL OCCLUDE AS IT LIFTS NORTH OVER SOUTHERN
MINNESOTA...WHILE THE OCCLUDED/COLD FRONT WILL SWEEP ACROSS THE AREA
LATE THIS EVENING AND THROUGH THE OVERNIGHT HOURS. SNOW/SLEET LOOK
TO BE ONGOING OVER NORTH-CENTRAL WISCONSIN AT THE START OF THE
EVENING WHILE CONDITIONS LOOK TO BE DRY FOR A PERIOD OVER
EAST-CENTRAL AND POSSIBLY FAR NORTHEAST WISCONSIN. THIS DRY PERIOD
OVER THE EAST WILL BE SHORT-LIVED HOWEVER...AS A BAND OF SHOWERS AND
EMBEDDED THUNDERSTORMS WILL MOVE THROUGH ALONG THE OCCLUDED/COLD
FRONT. PROGGED SOUNDINGS INDICATE THAT PTYPE SHOULD BE MAINLY RAIN
ACROSS THE REGION BY THE TIME THIS BAND ARRIVES...WHICH WILL LOOK TO
DUMP AROUND 0.75 INCHES OF RAIN OVER WESTERN SECTIONS OF THE CWA.
AMOUNTS SHOULD DROP OFF TO THE EAST AS INSTABILITY IS LOST THROUGH
THE NIGHT. BEST CHANCES OF THUNDER LOOK TO OCCUR OVER CENTRAL AND
EAST-CENTRAL AND WILL KEEP IT IN THE FORECAST. TEMPERATURES WILL
LIKELY PEAK LATE IN THE EVENING OR EARLY OVERNIGHT...JUST AHEAD OF
THE FRONT. LOWS IN THE 30S AND 40S.
MONDAY...OCCLUDED LOW PRESSURE WILL LIFT NE ACROSS NORTHERN
MINNESOTA. PRECIP WILL HAVE EXITED ALONG THE FRONT BY THE START OF
THE PERIOD AND SKIES WILL LIKELY TURN MOSTLY CLEAR FOR A PERIOD
DURING THE MORNING. HOWEVER...AS COLDER AIR FILTERS IN FROM THE
WEST AND MID-LEVEL TEMPS COOL...STEEPENING LOW LEVEL LAPSE RATES AND
WRAP AROUND MOISTURE WILL LEAD TO INCREASING CLOUDS FROM LATE
MORNING THROUGH THE REST OF THE DAY. COULD SEE A FEW INSTABILITY
RAIN AND SNOW SHOWERS DEVELOP OVER CENTRAL AND NORTHEAST WISCONSIN
IN THE AFTERNOON. GUSTY SOUTHWEST WINDS WILL BRING IN THE WARMEST
TEMPS THE AREA HAS SEEN IN SOME TIME...AND WILL GO WITH HIGHS
RANGING FROM THE LOW 40S NORTH TO THE MID 50S NEAR LAKE MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
FLOOD POTENTIAL IS PROBABLY THE MAIN CHALLENGE FOR THIS FORECAST
PERIOD. THE COLD FRONT MOVES THROUGH MONDAY WITH DRY BUT
SEASONABLE AIR FOLLOWING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT.
SNOW WILL PROBABLY BE GONE OVER MUCH OF THE AREA BELOW 1000 FT
ELEVATION BY THEN WITH THAT SNOW MELT PROBABLY CONTRIBUTING TO
RISES OF THE WOLF RIVER AND SMALL STREAMS OVER EAST CENTRAL
WISCONSIN. MODELS ARE NOW IN GENERAL AGREEMENT WITH SURFACE LOW THAT
MOVES NORTHEAST FROM SOUTHERN PLAINS TO LOWER MICHIGAN WEDNESDAY
THROUGH THURSDAY. LOOKS LIKE THIS WILL BE A LARGELY RAIN EVENT
UNLESS THE STORM TRACKS FURTHER SOUTH. A RAIN EVENT COUPLED BY
SNOW MELT IN THE NORTH WILL LIKELY CAUSE SOME FLOODING OF SMALL
STREAMS AROUND THE AREA BY THURSDAY BUT SIGNIFICANTLY COLDER AND
DRIER AIR WILL SLOW SNOW MELT FRIDAY AND SATURDAY.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1120 PM CDT SUN APR 14 2013
TEMPERATURES WILL CONTINUE TO GRADUALLY WARM OVERNIGHT...SO ANY
LINGERING FREEZING RAIN IN NC WI SHOULD COME TO AN END. SINCE TEMPS
HAVE RISEN TO JUST ABOVE FREEZING AT RHI/AUW/CWA...DO NOT PLAN TO
CARRY ANY FREEZING RAIN ON THE 06Z TAFS. A LARGE BAND OF SHOWERS WILL
ACCOMPANY A FRONTAL BOUNDARY AS MOVES THROUGH THE AREA OVERNIGHT. THE
SHOWERS SHOULD END FROM WEST TO EAST BETWEEN 08Z-10Z. THE MAIN FOCUS
FOR THUNDERSTORMS APPEARS TO HAVE SHIFTED SOUTH...SO WILL NOT MENTION
ANY TSTMS IN THE NEW SET OF TAFS. AFTER THE PCPN ENDS...SOME SCT
IFR/MVFR CIGS WILL LIKELY LINGER LATE TONIGHT INTO EARLY MONDAY.
GUSTY SW WINDS ARE EXPECTED TO DEVELOP BY MIDDAY MONDAY.
LLWS WILL CONTINUE ACROSS THE REGION UNTIL THE OCCLUDED FRONT
MOVES THROUGH OVERNIGHT. THE LLWS SHOULD WANE AT THE TAF SITES
FROM WEST TO EAST BETWEEN 08Z-10Z.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN APR 14 2013
CONTINUED CONCERNS FOR FLOODING ISSUES GIVEN EXPECTED
QPF WITH THE FRONTAL PASSAGE TONIGHT. AN ADDITIONAL THREE QUARTERS
TO AN INCH OF PRECIP MAY FALL OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN BY MONDAY MORNING. WARMER TEMPERATURES TONIGHT AND MONDAY
WILL ADD SNOW MELT INTO THE EQUATIONS. CONCERNS ADDRESSED IN CURRENT
ESF PRODUCT AND RIVER FLOOD STATEMENTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 1 AM CDT MONDAY FOR WIZ005-010>012-
018-019.
&&
$$
UPDATE.........KIECKBUSCH
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS TAUNTON MA
157 AM EDT WED APR 17 2013
.SYNOPSIS...
SCATTERED SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM WILL MOVE
ACROSS THE REGION WITH A COLD FRONT TONIGHT. DRY PLEASANT WEATHER
FOLLOWS WEDNESDAY INTO THURSDAY AS HIGH PRESSURE BUILDS ACROSS
NORTHERN NEW ENGLAND. A WARM FRONT MAY BRING A FEW PASSING SHOWERS
TO THE REGION THU NIGHT AND FRI. A PERIOD OF HEAVY RAIN WITH
PERHAPS A FEW THUNDERSTORMS ARE EXPECTED FRI NIGHT INTO SAT...WITH
DRIER/COOLER WEATHER FOLLOWING SUN AND MON.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
2 AM UPDATE...
THE EVOLUTION AND CHARACTERISTICS OF SHOWER ACTIVITY AHEAD OF AN
APPROACHING COLD FRONT HAS PROVEN DIFFICULT TO FORECAST. FEEL THE
LATEST RAP GUIDANCE HAS THE BEST HANDLE /EARLIER 16.12Z ECMWF MAY
BE A CLOSE SECOND/. EXPECT WIDELY SCATTERED SHOWERS TO IMPACT
SOUTHERN NEW ENGLAND INTO THE MORNING BY WHICH POINT THE COLD
FRONT SHOULD HAVE SWEPT THROUGH THE REGION MOVING SOUTH AND OUT TO
SEA. WILL CONTINUE WITH A MENTION OF ISOLATED THUNDER WITH
CONVECTIVE INDICES JUST ON THE CUSP.
TEMPERATURES AND DEWPOINTS REMAIN ON TRACK ALBEIT A DEGREE OR TWO
WARMER IN SOME AREAS THAN PRESENTLY FORECASTED. THE SLUGGISHNESS
OF THE COLD FRONT TO MOVE THROUGH THE REGION WILL LIKELY HAVE
IMPLICATIONS OF KEEPING TEMPERATURES MILDER THAN ORIGINALLY
THOUGH...ALLOWING WARMER CONDITIONS FOR TOMORROW.
WILL CONTINUE WITH MINIMUM TEMPERATURES TONIGHT AROUND THE MID TO
UPPER 40S. COLDEST SPOTS WILL BE THE HIGHER ELEVATIONS OF THE
BERKSHIRES AND MONADNOCKS /UPPER 30S/. WARMEST LOCALES ALONG THE
SHORES. SOUTHWESTERLY FLOW WILL REMAIN BLUSTERY AT TIMES AHEAD OF
THE COLD FRONT BACKING WEST-NORTHWEST WITH PASSAGE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
WEDNESDAY...
WITH UPPER LEVEL PATTERN BECOMING SOMEWHAT ZONAL ACROSS THE
NORTHEASTERN U.S...THE COLD FRONT WILL STALL S OF THE REGION.
HOWEVER...IT WILL BE FAR ENOUGH OFFSHORE THAT DRY CONDITIONS WILL
BE IN PLACE. MID AND HIGH CLOUDS WILL LINGER ACROSS SOUTHERN
AREAS WITH THE STALLED FRONT TO THE S. HIGH PRES WILL SLOWLY MOVE
ACROSS NORTHERN NEW ENGLAND DURING THE DAY...SO WINDS WILL BECOME
LIGHT N-NE. EXPECT DAYTIME HIGHS IN THE LOWER-MID 60S...EXCEPT IN
THE MID-UPPER 50S ALONG THE COAST.
WEDNESDAY NIGHT...
THE HIGH WILL MOVE ACROSS MAINE/EASTERN QUEBEC AS LOW PRES
DEVELOPS ACROSS THE MID MISSISSIPPI VALLEY. WILL SEE ANOTHER DRY
NIGHT...WITH MAINLY CLEAR SKIES ESPECIALLY ACROSS S NH AND N MA
WITH SOME MID AND HIGH CLOUDS LINGERING ACROSS THE S COAST. THE
CLOUDS WILL START TO INCREASE AFTER MIDNIGHT AS THE STALLED FRONT
TO THE S WILL START TO PUSH N AS A WARM FRONT. WILL BE A CHILLY
NIGHT ACROSS S NH WITH OVERNIGHT LOWS IN THE MID-UPPER 30S...
RANGING TO THE LOWER-MID 40S ALONG THE S COAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* FEW SHOWERS THU NIGHT INTO FRI AFTERNOON BUT NOT A WASHOUT
* HEAVY RAIN AND ISOLATED THUNDER LATE FRI NIGHT INTO SAT
* DRY WEATHER WITH BELOW NORMAL TEMPS SUN AND MON
DETAILS...
THURSDAY...
UPPER LEVEL RIDGING SHOULD RESULT IN A PLEASANT DAY. SOME
SUNSHINE IS EXPECTED AT LEAST FOR THE FIRST PART OF THE DAY...BUT
CLOUDS WILL INCREASE A BIT FROM THE WEST DURING THE AFTERNOON.
HIGHS SHOULD TOP OUT IN THE UPPER 50S AND LOWER 60S ACROSS MOST
LOCATIONS...BUT IT MAY BE SEVERAL DEGREES COOLER ALONG THE
IMMEDIATE COAST AS A RESULT OF SEA BREEZES.
THURSDAY NIGHT AND FRIDAY...
THE BEST DYNAMICS/FORCING WILL REMAIN WELL TO OUR WEST THU NIGHT
INTO FRI AFTERNOON. HOWEVER...A STRONG SOUTH TO SOUTHWEST LOW
LEVEL JET WILL RESULT IN WARM ADVECTION AND SOME MID LEVEL LIFT
INTO SOUTHERN NEW ENGLAND. THIS MAY RESULT IN A FEW SHOWERS FROM
TIME TO TIME...BUT CERTAINLY FAR FROM A WASHOUT AND MOST OF THE
TIME DRY WEATHER SHOULD DOMINATE. AS FOR TEMPS...DESPITE SOME
CLOUDS AROUND STRONG WARM ADVECTION SHOULD PUSH HIGHS FRI INTO THE
UPPER 60S AND LOWER 70S ACROSS MUCH OF THE REGION.
LATE FRIDAY NIGHT AND SATURDAY...
STILL A WAYS OUT...BUT THERE ARE SOME GOOD INDICATORS FOR A
PERIOD OF HEAVY RAINFALL ALONG WITH ISOLATED THUNDER AS A STRONG
COLD FRONT MOVES THROUGH THE REGION. DEEP MERIDIONAL FLOW SHOULD
RESULT IN PWAT VALUES OF AROUND 1.5 INCHES. STRONG FORCING/LIFT
SHOULD COMBINED WITH THE HIGH PWAT VALUES FOR A PERIOD OF HEAVY
RAINFALL. TIMING IS STILL TRICKY...BUT CURRENT INDICATIONS ARE FOR
LATE FRI NIGHT INTO MID AFTERNOON SAT FOR THE MAIN AFFECTS. AT
THIS TIME...THE FRONT LOOKS PROGRESSIVE ENOUGH TO PREVENT A
SIGNIFICANT FLOOD EVENT. HOWEVER...NUISANCE POOR DRAINAGE STREET
FLOODING IS CERTAINLY A POSSIBILITY.
AS FOR CONVECTIVE CHANCES...INSTABILITY PARAMETERS DON/T LOOK TO BE
ENOUGH FOR SEVERE WEATHER...BUT CERTAINLY COULD BE SOME ISOLATED
EMBEDDED THUNDER SO HAVE INCLUDED IN THE FORECAST. ALSO...WITH
THE STRONG LOW LEVEL JET THERE IS A LOW PROBABILITY THAT BRIEF
WIND ADVISORY CRITERIA IS MET.
SUNDAY AND MONDAY...
LARGE HIGH PRESSURE WILL BUILD INTO THE REGION RESULTING IN DRY
WEATHER BUT TEMPERATURES A BIT BELOW NORMAL FOR THE LATTER HALF OF
APRIL.
MONDAY NIGHT AND TUESDAY...
LOW CONFIDENCE BUT IF A WAVE OF LOW PRESSURE GETS CLOSE ENOUGH TO
US WE COULD HAVE A COLD RAIN. IF IT STAYS MORE OUT TO SEA THEN
WILL REMAIN DRY. JUST TOO EARLY TO SAY MUCH MORE AT THIS POINT SO
SOME LOW POPS IN THE FORECAST.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...
* MODERATE CONFIDENCE INTO MORNING...
* HIGH CONFIDENCE WEDNESDAY INTO WEDNESDAY NIGHT...
* MODERATE CONFIDENCE THURSDAY...
SCT -SHRA DIFFICULT TO FORECAST RESULTING IN MODERATE CONFIDENCE.
WILL PREVAIL WITH VCSH. LESSER CONFIDENCE CONCERNING MVFR CIGS AND
VSBY IMPACTS. SHOULD ANY -SHRA IMPACT TERMINALS...A BRIEF PERIOD
OF MVFR VSBYS IS CERTAINLY PLAUSIBLE. 2-3 KFT AGL 50 KT SW JET PER
BOS TDWR. LLWS TO IMPACT TERMINALS S AND E OF IJD-TAN-GHG INTO THE
MORNING.
THEREAFTER...VFR FOR WEDNESDAY INTO WEDNESDAY NIGHT. TWO CONCERNS...
SEA-BREEZES ALONG ALL SHORELINES AROUND 18Z...AND THE POSSIBILITY
FOR ISOLATED PATCHY FOG OVERNIGHT. HIGHER CONFIDENCE FOR THE PRIOR
OVER THE LATTER. WILL SEE INCREASING CLOUDS AND THE CHANCE OF
-SHRA INTO LATE THURSDAY FROM THE SW. FEEL VFR WILL PREVAIL.
KBOS TERMINAL...MODERATE CONFIDENCE.
UNCERTAINTY OVER -SHRA SO WILL PREVAIL VCSH. ANTICIPATING SEA-
BREEZE IMPACTS AROUND 18Z WITH WINDS BECOMING 090...REVERTING NE
AFTER DUSK.
KBDL TERMINAL...MODERATE CONFIDENCE.
WILL PREVAIL WITH VCSH UNDER SIMILAR CIRCUMSTANCES AT KBOS ABOVE.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
THURSDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE. PERIODS OF
MVFR-IFR CONDITIONS IN SCATTERED SHOWERS/LOW CLOUDS AND FOG
PATCHES. ISOLATED THUNDER AND LLWS ARE POSSIBILITIES FRI NIGHT/SAT
MORNING
SATURDAY NIGHT THROUGH SUNDAY...MODERATE CONFIDENCE IN MAINLY VFR
CONDITIONS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE THROUGH WEDNESDAY NIGHT.
TONIGHT...CONTINUED SMALL CRAFT WITH SW GUSTS UP TO 25-30 KT. MAY
SEE BRIEFLY HIGHER GUSTS IN ANY HEAVY DOWNPOURS OR TSTMS. WINDS
START TO DIMINISH AFTER MIDNIGHT AS FRONT PASSES AND SHIFT TO
W-NW.
WEDNESDAY...ANY LEFTOVER SMALL CRAFT GUSTS AND SEAS DIMINISH
QUICKLY WED MORNING. EXPECT NW WINDS TO SHIFT TO N-NE AND CONTINUE
TO DIMINISH AS HIGH PRES BUILDS N OF THE WATERS.
WEDNESDAY NIGHT...WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE TO HIGH CONFIDENCE THROUGH THE PERIOD.
THURSDAY AND FRIDAY...PERSISTENT SOUTHERLY FLOW AND LONG FETCH WILL
RESULT IN SEAS BUILDING TO SCA LEVELS OVER MOST OPEN WATERS THU
NIGHT/FRI. IN ADDITION...SCA WIND GUSTS WILL BE POSSIBLE AT TIMES
ESPECIALLY NEAR SHORE THU AND FRI AFTERNOON/S. AREAS OF FOG MAY
AFFECT THE WATERS THU NIGHT INTO FRI MORNING.
FRIDAY NIGHT AND SATURDAY...STRONG SOUTHWEST SCA WIND GUSTS ARE
EXPECTED AHEAD OF AN APPROACHING COLD FRONT. MAY EVEN BE A BRIEF
PERIOD OF MARGINAL GALE FORCE SOUTHWEST WIND GUSTS. SEAS SHOULD
APPROACH 10 FEET ACROSS THE SOUTHERN EASTERN ATLANTIC WATERS.
AREAS OF FOG AND PERHAPS EVEN AN ISOLATED THUNDERSTORM OR TWO WILL
BE POSSIBLE.
SATURDAY NIGHT AND SUNDAY...A PERIOD OF WESTERLY SCA WIND GUSTS ARE
POSSIBLE BEHIND THE STRONG COLD FRONT.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR
ANZ230>234-236.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR ANZ235-
237-250-251-254>256.
&&
$$
SYNOPSIS...FRANK/EVT
NEAR TERM...SIPPRELL
SHORT TERM...EVT
LONG TERM...FRANK
AVIATION...FRANK/SIPPRELL
MARINE...FRANK/EVT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1203 AM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 912 PM CDT TUE APR 16 2013
00Z SND FROM TOP AND DOWNSTREAM AT DDC AND AMA SHOW A FAIRLY STOUT
CAP ON THE BOTTOM OF THE EML. PARCELS ABOVE THE SHALLOW COLD
AIR-MASS MAY NOT REACH THEIR LFC`S UNTIL LATE TONIGHT WHEN DEEPER
MOISTURE ADVECTION AND A STRENGTHENING LLJ MAY CAUSE PARCELS TO
REACH THEIR LFC. THE HRRR AND RAP MODELS SEEM TO BE THE BEST JOB
WITH INITIALIZATION AND MAY HAVE THE BEST PERFORMANCE WITH
ELEVATED CONVECTION. BOTH MODELS SHOW ELEVATED CONVECTION
DEVELOPING ACROSS CENTRAL AND NORTH CENTRAL KS BY 9Z...WITH THE
ELEVATED THUNDERSTORMS MOVING NORTHEAST ACROSS THE NORTHWEST
COUNTIES OF THE CWA THROUGH THE EARLY MORNING HOURS. ELEVATED
CONVECTION MAY FORM LATE TONIGHT ACROSS SOUTH CENTRAL AND CENTRAL KS AND
INTENSIFY AS IT MOVES NORTHEAST INTO THE REMAINDER OF THE CWA. THE
RAP INCREASES MUCAPE TO 1500 TO 2000 J/KG ACROSS THE WESTERN
COUNTIES OF THE CWA AFTER 12Z. WHILE SFC TO 6KM BULK SHEAR WILL BE
50 TO 60 KTS...THUS SOME OF THE ELEVATED THUNDERSTORMS MAY DEVELOP
MID-LEVEL MESO`S AND PRODUCE LARGE HAIL. THE BIG QUESTION
CONTINUES TO BE CAP STRENGTH...AND WHEN AND WHERE THE ELEVATED
THUNDERSTORMS WILL DEVELOP. MY THINKING IS BETWEEN 7Z-8Z ACROSS
NORTH CENTRAL KS WITH FARTHER DEVELOPMENT ACROSS THE REMAINDER OF
THE CWA TOWARDS 12Z.
SCATTERED SHOWERS MAY DEVELOP BEFORE ANY ELEVATED
CONVECTION DOES...THUS I KEPT SOME POPS THROUGH THE LATE EVENING AND
EARLY MORNING HOURS ACROSS THE CWA.
GARGAN
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE APR 16 2013
SOUTHWEST FLOW ALOFT CONTINUES ACROSS THE CENTRAL PLAINS AS A UPPER
TROUGH DIGS SOUTH ACROSS THE WESTERN U.S. THIS AFTERNOON AT 19Z.
SURFACE FRONTAL BOUNDARY WAS LOCATED FROM NORTHERN TEXAS NORTHEAST
INTO ARKANSAS AND SOUTHEAST MISSOURI. FURTHER NORTH OF THE WARM
FRONT CENTRAL AND EASTERN KANSAS REMAIN IN THE COOL SECTOR WITH
TEMPERATURES IN THE 40S.
FOR TONIGHT...ISENTROPIC LIFT INCREASES THIS EVENING AS PARCELS ARE
LIFTED OVER THE COLD DOME NORTH OF THE WARM FRONT. MOISTURE
TRANSPORT VECTORS INCREASE THIS EVENING AS THE LOW LEVEL JET
INCREASES. LAPSE RATES IN THE MID LEVELS WILL STEEPEN AND ELEVATED
INSTABILITY WILL INCREASE AS WELL ACROSS CENTRAL AND EASTERN KANSAS.
GIVEN FAVORABLE SHEAR...MOISTURE AND INSTABILITY TONIGHT SOME STORMS
MAY BECOME SEVERE AND PRODUCE LARGE HAIL OVERNIGHT.
WEDNESDAY...DIFFERENCES EXIST BETWEEN THE GFS AND THE NAM...ECMWF AS
WELL AS THE UKMET. THE GFS IS FURTHER NORTH WITH THE WARM SECTOR
WHILE THE OTHERS KEEP IT ACROSS EAST CENTRAL KANSAS IN THE
AFTERNOON. AGAIN FAVORABLE SHEAR...INCREASING INSTABILITY AND
MOISTURE WILL COME TOGETHER FOR STRONG TO SEVERE STORMS. THE MORNING
CONVECTION COULD STILL BE PRODUCING HAIL. BY AFTERNOON...AS PARCELS
RISE UP OVER THE FRONT INTO INCREASINGLY UNSTABLE AIR
HOWEVER...SEVERE HAIL WILL REMAIN THE PRIMARY THREAT FOR THE EASTERN
2/3 OF THE FORECAST AREA...WITH RISK OF SURFACE BASED
STORMS/TORNADIC THREAT GENERALLY ALONG AND SE OF THE INTERSTATE 35
CORRIDOR. IF THE WARM AIR IS FURTHER NORTH THEN THE CONVECTION WILL
INCREASE FURTHER NORTH AS WELL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE APR 16 2013
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...
FRONT WILL CONTINUE TO PUSH SOUTH AND EAST OF I 35 THROUGH THE
EVENING. AS THE UPPER LEVEL TROUGH IN THE ROCKIES ADVANCES EASTWARD
INTO THE AREA STRONG FORCING AHEAD OF THE FRONT AND POST FRONTAL
WILL CONTINUE ACROSS THE NORTHEAST AND EAST CENTRAL AREAS...BUT
INSTABILITY WILL SLOWLY DECREASE THROUGH MIDNIGHT WITH AN ADDITIONAL
HALF OF ONE INCH OF RAIN...WITH LIGHTER AMOUNTS OF A QUARTER TO HALF
INCH IN THE NORTH CENTRAL. AS THE COLDER AND DRIER AIR ADVANCES EAST
WARD BEHIND THE FRONT...HIGH POPS ARE STILL WARRANTED...BUT PRECIP
AMOUNTS WILL BE ON THE DECLINE. AS THE COLDER AIR POURS INTO THE CWA
WEDNESDAY NIGHT INTO THURSDAY MORNING ON THE HEELS OF BLUSTERY NORTH
NORTHWEST WINDS...THERE IS A CHANCE FOR THE RAIN TO MIX WITH
SLEET...THEN SNOW IN THE FAR NORTH CENTRAL. UP TO AN INCH OF SNOW IS
POSSIBLE IN THE FAR NORTHWEST CORNER OF THE CWA BEFORE PRECIP
DECREASES TOWARDS MIDDAY. THE RAIN/SNOW MIX COULD MAKE IT AS FAR
EAST AS THE TURNPIKE ON THURSDAY AND LINGER OVER THE NORTHERN AND
EAST CWA THURSDAY EVENING ON THE BACKSIDE OF THE EXITING TROUGH.
AFTER LOWS WEDNESDAY NIGHT IN THE 40S EAST AND THE LOW TO MID 30S
WEST...HIGHS ON THURSDAY WILL ONLY RISE A FEW DEGREES FROM THE
MORNING LOWS.
A COLDER NIGHT IS IN STORE FOR THE AREA THURSDAY NIGHT WITH FREEZING
TEMPS EXPECTED IN MANY AREAS AS LOWS FALL INTO THE MIDDLE 20S NORTH
CENTRAL TO THE LOWER 30S NORTHEAST AND EAST CENTRAL. UNDER MOSTLY
SUNNY SKIES ON FRIDAY HIGH TEMPS WILL RECOVER BACK INTO THE UPPER
40S TO LOWER 50S.
FRIDAY THROUGH TUESDAY...
FRIDAY NIGHT THE LONG WAVE TROUGH WILL CONTINUE TO ADVANCE EASTWARD
AS SURFACE HIGH PRESSURE SETTLES OVERHEAD. WITH LIGHT WINDS AND A
COLD AIR MASS IN PLACE IT WILL BE QUIET CHILLY SATURDAY MORNING
AS LOW TEMPERATURES DROP INTO LOW 30S WHICH IS WELL BELOW NORMAL
THIS TIME OF YEAR. THIS MEANS THERE IS THE POTENTIAL FOR FROST
ACROSS PARTS OF THE REGION. ON SUNDAY A SHORTWAVE WILL DIVE
SOUTHEAST INTO THE NORTHERN AND CENTRAL PLAINS. AHEAD OF THE
APPROACHING SHORTWAVE LOW LEVEL SOUTHERLY FLOW WILL ALLOW MOISTURE
TO RETURN TO THE AREA. THIS BRINGS A CHANCE OF SHOWERS AND
THUNDERSTORMS ON SUNDAY AND MONDAY. THE MAIN TROUGH WILL PROGRESS
INTO THE NORTHERN US AND A TRAILING COLD FRONT WILL EXTEND SOUTH
ACROSS THE REGION. BEHIND THE COLD FRONT ANOTHER SHOT OF
UNSEASONAL COLD AIR WILL FILTER SOUTH ACROSS THE AREA. THE ECMWF
IS SUGGESTING POST FRONTAL PRECIPITATION WHICH WOULD MEAN A MIX OF
RAIN AND SNOW MONDAY NIGHT AND TUESDAY MORNING. DUE TO LOW
UNCERTAINTY DID NOT ADD SNOW INTO THE FORECAST ATTM. THIS SHOT OF
COLD AIR COULD ALSO BRING ANOTHER CHANCE OF FROST MONDAY
NIGHT...BUT WILL HAVE TO MONITOR ADDITIONAL MODEL OUTPUT BEFORE
ADDRESSING THE DETAILS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1200 AM CDT WED APR 17 2013
MVR CEILINGS WILL GRADUALLY DROP TO THE IFR CATEGORY THROUGH THE
EARLY MORNING HOURS. SHOWERS AND THUNDERSTORMS WILL DEVELOP
THROUGH THE MORNING...THEN WE MAY SEE A BREAK IN THE LATE MORNING
BEFORE SHOWERS AND THUNDERSTORMS REDEVELOP AND CONTINUE INTO THE
EVENING. THERE MAY BE A WINDOW OF MVFR CEILINGS THIS AFTERNOON BUT
IFR CEILINGS SHOULD DEVELOP BEHIND THE COLD FRONT THIS EVENING.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...53
LONG TERM...SANDERS/63
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 AM EDT WED APR 17 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NRN QUEBEC THROUGH JAMES BAY INTO NRN ONTARIO WAS DEPARTING TO THE
EAST. UPSTREAM...SW FLOW PREVAILED THROUGH THE PLAINS AHEAD OF A
TROUGH FROM THE NRN ROCKIES THROUGH THE GREAT BASIN. WITH CONFLUENT
FLOW WITH QVECTOR DIV AND SUBSIDENCE OVER THE NRN GREAT LAKES...THE
SCT FLURRIES HAD DIMINISHED THIS AFTERNOON.
AS HIGH PRES BUILDS INTO NRN ONTARIO TONIGHT BRINGING ENE ACYC FLOW
INTO UPPER MI AND DAYTIME HEATING FADES...EXPECT THAT WINDS WILL
DIMINISH AND CLOUDS WILL THIN OUT ENOUGH FOR TEMPS TO DROP INTO THE
20S.
AS THE WRN TROUGH EDGES TO THE EAST AND A SFC-850 MB TROUGH DEVELOPS
FROM THE SRN PLAINS INTO THE UPPER MS VALLEY...WAA AND MOISTURE
ADVECTION WILL INCREASE QUICKLY BY WED AFTERNOON. THE INITIAL AREA
OF PCPN IS EXPECTED INTO THE WEST...WHERE 295K-300K ISENTROPIC LIFT
IS STRONGEST. GIVEN THE DRY ERLY FLOW AS THE HIGH GRADUALLY MOVES
EAST THROUGH NRN ONTARIO...THE SLOWER PROGRESSION OF PCPN INTO
UPPER...PER NAM...WAS PREFERRED COMPARED TO THE GFS/ECMWF. EXPECT
ENOUGH OF A LINGERING WARM LOWER LAYER FOR MOSTLY RAIN AT THE ONSET
OF MAINLY LIGHT PCPN AS AFTERNOON TEMPS CLIMB INTO THE 40F TO 45F
RANGE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
MAIN ATTENTION FOR THE LONG TERM PORTION OF THE FORECAST ARE THE
TWO WAVES OF PRECIPITATION ASSOCIATED WITH ENERGY AND LOW PRESSURE
SYSTEMS EXITING FROM THE UPPER TROUGH CURRENTLY MOVING THROUGH THE
WESTERN CONUS.
FIRST WAVE WILL BE INFLUENCING THE AREA AT THE START OF THE LONG
TERM PERIOD WILL BE ASSOCIATED WITH SHORTWAVE ENERGY EJECTING AHEAD
OF THE TROUGH EXPECTED TO BE IN THE CENTRAL ROCKIES. AT THE
SURFACE...A LOW CENTERED IN WESTERN OKLAHOMA AND THE
PANHANDLE OF TEXAS WILL BEGIN ELONGATING A TROUGH NORTHEAST INT HE
MID MISSISSIPPI VALLEY ON WEDNESDAY AFTERNOON AND THEN NORTHEAST
INTO NORTHERN LAKE MICHIGAN BY 12Z THURSDAY. WITH THE STRONG MID
LEVEL FORCING ASSOCIATED WITH 925-700MB WARM AIR ADVECTION AND
LIKELY CONVECTION ON THE EAST SIDE OF THE TROUGH...WOULD EXPECT THE
HEAVIEST PRECIPITATION TO BE JUST TO THE SOUTHEAST OF THE CWA OR
BRUSH THE SOUTHEAST PART OF THE CWA. BUT...WITH THE AREA UNDER THE
RIGHT REAR OF THE UPPER JET AND ENOUGH OVERRIDING FLOW WITH THAT
WARM AIR ADVECTION AND ISENTROPIC ASCENT ON THE 280-300K
SFCS...STILL THINK THAT THERE WILL BE ENOUGH FORCING FOR MODERATE
PRECIPITATION ACROSS MUCH OF THE CWA. GENERAL MODEL CONSENSUS OF
0.50-0.80 INCH SEEMS REASONABLE FOR MUCH OF THE AREA...WITH VALUES
APPROACHING AN INCH ALONG THE LAKE MICHIGAN SHORELINE. THIS TRICKY
PART OF THIS FORECAST IS WHAT AMOUNT OF THE PRECIP WILL FALL AS
RAIN OVER THE WESTERN HALF OF THE CWA DUE TO THE ELEVATED WARM
LAYER. THERE CONTINUES TO BE SOME DISCREPANCY IN THE AMOUNT OF WARM
AIR THAT MOVES OVER THE CENTRAL CWA AND HOW FAR WEST THAT MOVES.
THINK THE FAR WESTERN CWA WILL LIKELY SEE MAINLY SNOW /FROM
KCMX TO KIWD/...BUT COULD SEE A BRIEF PERIOD OF FREEZING RAIN
OVERNIGHT. THE AREA BETWEEN THERE AND A LINE FROM MARQUETTE TO IRON
MOUNTAIN IS THE TRICKY AREA...SINCE THERE WILL LIKELY BE ENOUGH
WARM AIR TO MELT THE SNOW ALOFT. THEN PRECIP TYPE COMES DOWN TO
SURFACE TEMPERATURES...SINCE 925MB TEMPS ARE WELL BELOW FREEZING.
WILL CONTINUE TO MENTION MAINLY FREEZING RAIN IN THAT AREA...WITH
SOME MENTION OF SNOW. ALL IN ALL...APPEARS THAT THIS WILL LIKELY BE
A SOLID ADVISORY FOR THE WESTERN HALF OF THE CWA AND THERE IS SOME
CONCERN FOR DECENT ICE ACCUMULATION DEPENDING ON WHAT THE SURFACE
TEMPS ARE. THIS ENERGY WILL SHIFT NORTHEAST ON THURSDAY MORNING AND
WITH THE 850MB FLOW BECOMING MORE SOUTHWEST...WOULD EXPECT THE
PRECIPITATION TO WEAKEN HEADING INTO THE AFTERNOON.
NEXT SYSTEM TO AFFECT THE AREA WILL BE AS THE UPPER TROUGH LIFTS TO
THE NORTHEAST AND MOVES TOWARDS THE UPPER GREAT LAKES ON THURSDAY
NIGHT INTO FRIDAY. THIS WILL INTENSIFY A LOW ALONG THE LINGERING
SURFACE TROUGH AND THEN LIKELY TRACK TOWARDS THE STRAITS OF
MACKINAC BY 12Z FRIDAY. THE MAIN CONCERN FOR WIDESPREAD
PRECIPITATION FOR THE AREA IS THE TRACK/LOCATION OF THE DRY SLOT
SURGING NORTHEAST ON THURSDAY NIGHT INTO FRIDAY. THERE ARE STILL
SOME DIFFERENCES IN THE LOW TRACK WITH THE NAM/GEM...SO OPTED TO
FOLLOW THE MORE CONSISTENT IDEA OF THE GFS/ECMWF FOR THE FORECAST.
LATEST INDICATIONS IN THE MODELS THAT THE DRY SLOT WILL AFFECT THE
CENTRAL/EASTERN CWA...BETWEEN THE DEFORMATION PRECIPITATION
AFFECTING THE WESTERN CWA AND THE CONVECTION AND HEAVY RAIN
AFFECTING LOWER MICHIGAN AHEAD OF THE COLD FRONT. THUS...WOULD
EXPECT THE HEAVIEST PRECIPITATION TO OCCUR OVER THE WESTERN THIRD OF
THE CWA THURSDAY NIGHT INTO FRIDAY...WITH THE REST OF THE AREA
SEEING LIGHTER PRECIPITATION. BASED OFF THE THERMAL PROFILE...THAT
ALSO SEEMS TO BE THE LOCATION OF THE RAIN/SNOW/MIXED PRECIPITATION
LINE...LARGELY STRETCHING FROM KIMT/KSAW. THE CONCERN FOR THE
CENTRAL CWA WILL BE THE EXPECTED AREA OF SUBFREEZING TEMPERATURES
BELOW 875MB WHICH WOULD LEAD TO THE RAIN FREEZING WHEN IT GETS TO
THE SURFACE. OUT WEST...THE PRECIPITATION WILL LIKELY START OUT AS
FREEZING RAIN AS THE WARM NOSE ROTATES THROUGH AND THEN TRANSITION
TO SNOW FROM WEST TO EAST. WHEN COMBINED WITH THE NORTHERLY FLOW OFF
LAKE SUPERIOR WITH 850MB TEMPS FALLING TO -10C ON FRIDAY SHOULD SEE
LAKE ENHANCEMENT REALLY INCREASE AMOUNTS OVER GOGEBIC/ONTONAGON
COUNTIES THROUGH THE DAY ON FRIDAY. WITH THAT AREA SEEING BOTH THE
DEFORMATION PRECIPITATION AND THE LAKE ENHANCEMENT...CURRENT
EXPECTATION WOULD BE WARNING SNOWFALL AMOUNTS AND SOME LOCATIONS
COULD SEE SOME SIGNIFICANT SNOWFALL AMOUNTS FOR MID-LATE APRIL. IN
ADDITION TO THE SNOW...STRONG NORTHERLY WINDS FROM THE KEWEENAW
THROUGH GOGEBIC COUNTY WILL LEAD TO NEAR BLIZZARD CONDITIONS EVEN
THOUGH THE SNOW WILL LIKELY BE ON THE WETTER SIDE INITIALLY.
WILL CONTINUE THE SPS FOR THE WEDNESDAY NIGHT THROUGH FRIDAY
PERIOD...SINCE I FEEL THAT ENCOMPASSES THE ENTIRE SYSTEM WELL AND
SINCE THE THE MOST SIGNIFICANT EVENT WILL BE THE SECOND SYSTEM.
COULD HAVE DONE A LONG PERIOD WATCH TO COVER BOTH EVENTS...BUT SINCE
THE FIRST WAVE SEEMS TO BE MORE OF AN ADVISORY SITUATION AND THEN A
BRIEF BREAK ON THURSDAY AFTERNOON...WASN`T SURE IF THAT WOULD COME
ACROSS WELL WITH A LONG TERM WATCH HEADLINE.
EXPECT THE LAKE ENHANCED SNOW TO CONTINUE INTO FRIDAY NIGHT BUT
WILL QUICKLY COME TO AN END ON SATURDAY AS THE UPPER TROUGH LIFTS
TO THE NORTHEAST AND SURFACE HIGH PRESSURE BUILDS OVER THE AREA.
THIS SHOULD LEAD TO A NICE BUT COOL START TO THE WEEKEND...WITH
HIGHS ONLY REACHING THE 30S IN MOST LOCATIONS. THEN AS THE HIGH AND
UPPER RIDGE SHIFTS TO THE EAST ON SUNDAY...THE NEXT WAVE FROM THE
PACIFIC NORTHWEST WILL BE APPROACHING THE AREA FOR SUNDAY NIGHT AND
CONTINUING INTO MONDAY NIGHT AND TUESDAY. THERE CONTINUES TO BE
SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND THERE ENSEMBLE
MEANS...BUT THE GENERAL IDEA OF THE UPPER TROUGH AND COLD FRONT
MOVING THROUGH THE AREA DURING THAT TIME SEEMS REASONABLE. THE AREA
WILL LIKELY SEE A BRIEF WARM UP FOR SUNDAY INTO MONDAY...BACK INTO
THE 40S...BUT THEN COOL TO BELOW NORMAL VALUES BEHIND THE COLD FRONT
ON TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 410 AM EDT WED APR 17 2013
BAND OF MOISTURE/MVFR CIGS THAT HAS BEEN DRIFTING S ACROSS NRN
ONTARIO AND LAKE SUPERIOR SHOULD LEAD TO OCNL MVFR CIGS AT KCMX/KSAW
OVERNIGHT INTO THE MORNING HRS. MVFR CIGS SHOULD THEN SCATTER OUT BY
LATE MORNING. AT KIWD...DOWNSLOPE COMPONENT TO DEVELOPING LIGHT
EASTERLY WIND SHOULD WORK TO MAINTAIN VFR CONDITIONS THRU THE NIGHT.
SURGE OF WARM/MOISTURE N INTO THE GREAT LAKES LATE THIS AFTN/TONIGHT
WILL BRING A WINTRY MIX OF PCPN TO ALL 3 SITES. EXPECT PCPN TO BEGIN
AS -SN OR BRIEFLY -SNRA AT KIWD EARLY EVENING AND THEN MIX WITH PL
BY LATE EVENING AS WARMER AIR ALOFT CONTINUES TO SURGE N. DOWNSLOPE
COMPONENT TO E WIND SHOULD HELP TO KEEP CONDITIONS FROM FALLING BLO
MVFR AT KIWD. FARTHER INTO THE COLD AIR...PCPN SHOULD BE ALL SN AT
KCMX WHEN IT BEGINS IN THE EVENING. EXPECT CONDITIONS AT KCMX TO
FALL TO IFR SOON AFTER THE SNOW BEGINS DUE TO UPSLOPE E WIND. AT
KSAW...PCPN SHOULD BEGIN AS -SNPL IN THE EVENING AND THEN MIX WITH
OR CHANGE TO MAINLY -FZRA BY LATE EVENING. CONDITIONS AT KSAW SHOULD
FALL TO LOW MVFR...PERHAPS IFR...AFTER THE PCPN BEGINS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 436 PM EDT TUE APR 16 2013
WINDS WILL STAY BELOW 30 KNOTS THROUGH THU BEFORE INCREASING OUT OF
THE NORTH THURSDAY NIGHT INTO FRIDAY NIGHT WHEN NORTH GALES ARE
LIKELY AS A DEEP LOW PRESSURE SYSTEM MOVES TOWARD NORTHERN LAKE
MICHIGAN AND EAST UPPER MICHIGAN. THERE IS THE POTENTIAL FOR HIGHER
END GALES WITH THIS SYSTEM IN THE 40 TO 45 KNOT RANGE. THE WINDS
WILL DIMINISH FRI NIGHT INTO SAT AS THE LOW MOVES QUICKLY TO THE
NORTHEAST OF THE REGION AND HIGH PRES BUILDS IN FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EDT
THURSDAY FOR MIZ001-003>005-084.
WINTER WEATHER ADVISORY FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO
10 AM EDT /9 AM CDT/ THURSDAY FOR MIZ002-009.
LAKE SUPERIOR...
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH LATE FRIDAY NIGHT
FOR LSZ263>266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...JLB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1215 AM CDT Wed Apr 17 2013
.UPDATE...
Issued at 840 PM CDT TUE APR 16 2013
00Z raobs from surrounding sites as well as sites to the south reveal
a very stout elevated mixed layer (EML) that will be difficult to
overcome. Lack of radar returns within a 300 mile radius confirms
this. Have already lowered evening PoPs as a result and am
considering lowering them after midnight as well. Thinking scattered
coverage vs widespread as current PoPs would indicate. Would like to
get a look at the 00Z NAM before committing to lowering the PoPs. Do
believe the 00z RAP looks reasonable with best chances for convection
over the northern /12 of CWA where cap should be weaker.
&&
.SHORT TERM...(This Evening through Wednesday)
Issued at 425 PM CDT TUE APR 16 2013
Current water vapor imagery and H5 heights indicate a vigorous
trough moving from eastern Ontario into Quebec with associated cold
front draped across the eastern Great Lakes region and into the Ohio
River Valley. Southwest flow aloft will continue over the central
portion of the country as an upper level ridge strengthens in
response to a relatively broad trough continuing to dig into the
inter-mountain west and Great Basin. At the surface...stationary/warm
front extends from central Texas to south-central Oklahoma and on up
into northwest Arkansas and southeast Missouri. Temperatures in the
upper 70s to low 80s made for a nice afternoon south of the this
front with temperatures in the 40s and 50s just north of the frontal
boundary.
Current elevated front will be the focus for convection tonight and
through tomorrow night. Upper level diffluence will increase as the
western trough digs into the Great Basin. With moisture continuing to
pool along and south of the warm front, and steepening lapse rates,
expect elevated scattered thunderstorms to develop near the front
late this evening. Much of the overnight activity will remain along
the 700mb thermal ridge as low-level jet increases across the south-
central plains. Primary severe threat looks to be large hail overnight
tonight and early tomorrow morning as instability increases and bulk
shear values increase to near 50kts. Both the GFS and EC have at
least 500 J/kg of CAPE across much of the CWA and increasing to
around 1500 J/kg by tomorrow afternoon.
Thunderstorm coverage will increase through tomorrow morning and
another chance for severe weather by tomorrow afternoon and evening.
Given decent moisture profiles and the chance for heavy rainfall in
many locations, have decided to issue a flash flood watch
encompassing the entire CWA. The flash flood watch will extend from
noon tomorrow through Thursday. Felt that the main threat would not
be recognized until tomorrow, especially north of I-70 where flash
flood guidance has suggested that higher rainfall amounts will be
needed to achieve saturation and then runoff. Storm relative flow
aligned generally parallel to the surface front will allow for
training of thunderstorm and areas receiving excessive rainfall
amounts.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 425 PM CDT TUE APR 16 2013
Wednesday Night...severe weather may be ongoing as we transit into
the evening and overnight hours of Wednesday. Warm sector showers
and thunderstorm activity will last into the evening hours of
Wednesday before a cold front sweeps from west to east across the
forecast region early late Wednesday night through the afternoon
hours of Thursday. There will be a ongoing threat of severe weather,
though as the evening progresses the instability fueling the
potentially severe storms will be waining taking the threat for
severe weather with it. However, the potential for large hail,
damaging winds and isolated tornadoes will persist into the early
evening hours of Wednesday. As the front moves through the threat
will transit to hail and damaging winds for the late night hours,
though with precipitable water values of 1.5 inches expected and
winds running parallel to the advancing cold front, heavy rain and
flooding will be a persistent concern.
Thursday...severe weather threat should come to an end by the early
morning hours, if the waining instability hasn`t already brought the
threat to an end Wednesday night. However, rain on the backside of
the front may persist long enough to exacerbate the already wet
conditions, which could keep the flooding threat going through much
of the daylight hours. Will leave it to later shifts to perhaps
cancel the Flash Flood Watch early if need be. Otherwise, with the
cold air on the back side of this system, have included a brief
mention of rain and snow early Friday morning, though no
accumulations are expected even if it where all snow.
With the cold temperatures once again sweeping across the region
behind the cold front, expect readings to be suppressed below normal
through the weekend and into next work week, when another reinforcing
shot of cold air will sweep into the Plains States...again.
Otherwise, a shortwave trough in the northwest flow late in the
weekend may bring more showers back to the region, first as it lifts
a modest warm front into Iowa Sunday, before the reinforcing shot of
cold air arrives possibly Monday or Tuesday. This will keep the
threat of rain across the region from Sunday afternoon through
Tuesday, with below normal temperatures.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1210 AM CDT WED APR 17 2013
Scattered elevated showers now heading towards the terminals and
expect to see this area increase in coverage as it spreads across
northern MO overnight. Thunder chances may be more isolated or widely
scattered but increase as sunrise approaches. Will likely see
several periods of thunderstorms during the during this forecast
period with timing being a problem due to the activity being elevated
and not tied to any one boundary.
MVFR ceilings top start off but they will gradually lower overnight
as the depth of the moisture deepens. MVFR fog also expected to form
as the showers become more widespread and continuous on Wednesday.
Brisk easterly winds until a warm front surges north late in the
afternoon. This should also allow ceilings to improve some, but still
remain MVFR. A cold front will sweep through towards the end of the
forecast with a line of thunderstorms accompanying it. Ceilings are
also expected to drop to IFR in the post frontal airmass.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from Noon CDT today through Thursday evening
FOR KSZ025-057-060-102>105.
MO...FLASH FLOOD WATCH from Noon CDT today through Thursday evening
FOR MOZ001>008-011>017-020>025-028>033-037>040-043>046-053-
054.
&&
$$
UPDATE...MJ
SHORT TERM...PMM
LONG TERM...Cutter
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1213 AM CDT WED APR 17 2013
UPDATE TO AVIATION
.UPDATE...
ISSUED AT 951 PM CDT TUE APR 16 2013
FORECAST UPDATED TO ACCOUNT FOR HOURLY TRENDS PERTAINING TO THE
PESKY FRONT THAT IS LINGERING ABOUT THE AREA. THERE CONTINUES TO
BE A SIGNIFICANT TEMPERATURE AND MOISTURE DIFFERENCE ACROSS THE
BOUNDARY AND FURTHER REFINEMENTS ARE LIKELY AS THE NIGHT PROGRESSES.
OBSERVATIONS FROM THIS EVENING SUGGEST THAT MUCH OF THE REGION
WILL REMAIN CAPPED INTO THE OVERNIGHT HOURS. PAST FEW VERSIONS OF
THE RAP WEAKEN THE CAP OF AN ELEVATED PARCEL (AROUND 875 TO 850
MB) IN THE 08Z TO 10Z RANGE ACROSS FAR NORTHWEST PORTIONS OF THE
OUTLOOK AREA. EVEN STILL...THE 850MB FRONT APPEARS TO BE SETTING
UP ACROSS NORTHERN PORTIONS OF KS/MO. WILL NEED TO MONITOR ANY
CONVECTION DEVELOPING IN CENTRAL/WESTERN KANSAS AND THIS MAY CLIP
AREA ALONG/NORTHWEST OF A LINE FROM PITTSBURG KS TO THE LAKE OF
THE OZARKS REGION. PREVIOUS FORECAST UPDATE SHUNTED POPS TO THIS
AREA AND WILL TWEAK AS NECESSARY. WITH AROUND 1500 J/KG OF MUCAPE
POSSIBLE OVERNIGHT...ANY STORMS THAT ARE ABLE TO DEVELOP/MOVE INTO
THE AREA (WHICH WOULD BE ELEVATED IN NATURE) COULD POSE A
MARGINALLY SEVERE HAIL RISK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 644 PM CDT TUE APR 16 2013
A PRETTY INCREDIBLE TEMPERATURE GRADIENT EXISTED OVER THE OZARKS
THIS EVENING...AS A STALLED OUT FRONTAL SYSTEM WAS POSITIONED FROM
TABLE ROCK LAKE UP TO WINONA.
IN CENTRAL MISSOURI...TEMPERATURES WERE IN THE 40S...WHILE MIDDLE
70S WERE COMMON IN PLACES NEAR THE ARKANSAS STATE LINE.
WE MADE SOME ADJUSTMENTS REGARDING PRECIPITATION CHANCES. WE TOOK
OUT POPS FOR LOCATIONS SOUTH OF THE WARM FRONT...AS THIS AIRMASS
REMAINS INHIBITED. WITH NO FORCING MECHANISM TO TRIGGER CONVECTION
WITHIN THE WARM SECTOR...THESE AREAS SHOULD REMAIN DRY THROUGH
TONIGHT.
SHOWERS AND MAYBE A FEW THUNDERSTORMS ARE POSSIBLE NORTH OF
INTERSTATE 44 CORRIDOR. LAST NIGHT...THE CONVECTION WAS POSITIONED
CLOSELY WITH THE 850MB FRONT...WHICH IS UP ACROSS WEST CENTRAL AND
CENTRAL MISSOURI TONIGHT. THESE LOCATIONS WILL EXPERIENCE THE
BETTER CHANCES FOR RAIN...OTHERWISE...MOST LOCATIONS WILL REMAIN
DRY TONIGHT.
THE FRONT SHOULD BEGIN TO LIFT NORTHWARD THROUGH THE WEDNESDAY
MORNING HOURS. THIS WILL CAUSE TEMPERATURES ACROSS MOST OF THE CWA
TO WARM INTO THE 70S AND 80S.
THUNDERSTORMS WILL BE POSSIBLE...PARTICULARLY DURING THE AFTERNOON
AND EVENING HOURS...WITH SOME OF THE THESE STORMS BECOMING SEVERE.
CRAMER
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 228 PM CDT TUE APR 16 2013
THE CONVECTION WILL LIKELY FORM INTO A LINEAR MCS DURING THE
EVENING WITH THE MAIN RISK SHIFTING TO STRAIGHT LINE WIND DAMAGE.
HOWEVER WITH STRONG LOW LEVEL SHEAR PERSISTING THROUGH THE
NIGHT...CAN NOT RULE OUT A FEW QLCS TORNADOES WITHIN THE LINE. THE
FRONT (SIMILAR TO LAST WEEKS SYSTEM) WILL ONLY SLOWLY MAKE
PROGRESS INTO THE CWA BY THURSDAY MORNING WITH THE UPPER LEVEL JET
STREAK LIKELY AIDING IN DEVELOPING LOW PRESSURE ALONG THE FRONTAL
BOUNDARY THROUGH THE MORNING HOURS THURSDAY. THE EASTERN OZARKS
WILL LIKELY HAVE THE BEST CHANCE OF SEEING REDEVELOPMENT OF SEVERE
STORMS DURING THE AFTERNOON/EVENING ON THURSDAY BEFORE THE FRONT
PUSHES EAST OF THE AREA.
COLDER AIR WILL PUSH IN (LIKE LAST WEEK) BEHIND THE FRONT WITH
TEMPERATURES DROPPING INTO THE LOW TO MID 30S OVER THE WESTERN CWA
THURSDAY NIGHT AND MUCH OF THE AREA FRIDAY NIGHT. WILL NEED TO
MONITOR FOR POTENTIAL OF FROST/FREEZE HEADLINES.
SHOULD SEE A MODERATING TEMPERATURE TREND OVER THE WEEKEND WITH
GENERALLY DRY CONDITIONS...HOWEVER UNSETTLED CONDITIONS APPEAR
LIKELY FOR THE FIRST HALF OF NEXT WEEK AS AN UPPER LEVEL TROUGH
BEGINS TO DEVELOP IN THE CENTRAL U.S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1213 AM CDT WED APR 17 2013
EXTRAORDINARY CHALLENGING FORECAST FOR THE NEXT 24 HOURS. SURFACE
COLD FRONT HAS ONCE AGAIN MOVED SOUTH OF THE AREA. THE BEHAVIOR OF
THIS FRONT IS ONE OF THE MORE CRUCIAL ISSUES OF THE FORECAST AS IT
WILL DICTATE HOW CURRENT CIGS BEHAVE AND WHETHER OR NOT SHRA/TSRA
WILL DEVELOP DURING THE DAY WEDNESDAY. HAVE GENERALLY FOLLOWED A
CONSENSUS OF THE SHORT RANGE...MESOSCALE MODELS THAT SLOWLY LIFT
THE FRONT BACK NORTHWARD THROUGH THE AREA OVER THE NEXT 12 HOURS.
IFR CIGS AT JLN/SGF SHOULD TENUOUSLY HOLD...THOUGH IT IS WORTH
NOTING THAT CLEARING IS LITERALLY JUST MILES TO THE SOUTH OF THE
AERODROMES. BBG SHOULD REMAIN VFR AS A MID LEVEL DECK OVERSPREADS
THE AREA IN THE NEXT FEW HOURS. SCATTERED THUNDERSTORMS WILL BE
POSSIBLE ALONG THE WARM FRONT WEDNESDAY MORNING INTO THE EARLY
AFTERNOON HOURS. CONFIDENCE IN OCCURRENCE AT BBG/SGF IS TOO LOW TO
PUT MORE THAN VCTS IN...CONFIDENCE IN ACTIVITY AFFECTING JLN IS
HIGHER AND HAVE USED A TEMPO FOR THE LATE MORNING/EARLY AFTERNOON
HOURS. ONCE THE WARM FRONT LIFTS NORTH OF THE REGION...THE
ATMOSPHERE SHOULD BE CAPPED AND HAVE KEPT ANY MENTION OF THUNDER
OUT. CIGS SHOULD LIFT TO LOW END VFR WITH GUSTY SOUTHERLY WINDS
DEVELOPING THROUGH THE DAY WEDNESDAY. LOW LEVEL WIND SHEAR WILL BE
AN ISSUE BOTH THIS MORNING AND AGAIN TONIGHT.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH FROM NOON CDT TODAY THROUGH LATE THURSDAY
NIGHT FOR MOZ055>058-066>071-077>081-088>091-093-094-101-
102.
KS...FLASH FLOOD WATCH FROM NOON CDT TODAY THROUGH LATE THURSDAY
NIGHT FOR KSZ073-097-101.
&&
$$
UPDATE...GAGAN
SHORT TERM...CRAMER
LONG TERM...LINDENBERG
AVIATION...GAGAN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
135 AM EDT WED APR 17 2013
.SYNOPSIS...
AN INCREASINGLY WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE OVER THE
AREA UNTIL A COLD FRONT CROSSES THE REGION LATE FRIDAY AND FRIDAY
NIGHT. COOL HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH THROUGH
THE WEEKEND.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
AS OF 1040 PM TUESDAY...
MAIN FORECAST CONCERNS OVERNIGHT INTO WEDNESDAY CENTER ON TWO ITEMS:
1.) EXTENT OF FOG OVERNIGHT AND POTENTIAL FOR DENSE FOG; 2.) IF BAND
OF CONVECTION DRIFTING ESE ACROSS WV EARLY THIS EVENING WILL HAVE
ANY IMPACTS ON OUR WEATHER BY MORNING.
AREAS OF BROKEN STRATOCU EARLIER THIS EVENING HAVE GAVE WAY TO
EITHER CLEAR SKIES OR SCATTERED PATCHES OF STRATOCU. TEMPS HAVE
COOLED INTO THE 60S AREAWIDE LATE THIS EVENING WHILE SFC DEWPOINTS
HOLD IN THE MID-UPPER 50S TO NEAR 60. LIGHT S-SW WIND STILL BEING
REPORTED BY MANY SITES THOUGH SOME AWOS SITES IN THE SOUTH HAVE GONE
CALM. SINCE SKIES EXPECTED TO REMAIN MOSTLY CLEAR ACROSS THE SOUTH
AND EAST SECTIONS OF FORECAST AREA...WILL LIKELY SEE AREAS OF FOG
DEVELOP BETWEEN 3 AM - 5 AM WITH POCKETS OF DENSE FOG PROBABLE NEAR
BODIES OF WATER. DO NOT ANTICIPATE DENSE FOG BEING WIDESPREAD ENOUGH
TO REQUIRE THE ISSUANCE OF AN ADVISORY. ACROSS THE
PIEDMONT...ESPECIALLY THE NW PIEDMONT...CLOUD DEBRIS BLOW OFF FROM
CONVECTION CROSSING THE LOWER OH VALLEY AND CENTRAL APPALACHIANS
WILL LIKELY PROHIBIT FOG FORMATION OVERNIGHT. MIN TEMP FORECAST
APPEARS ON TARGET...55-60 DEGREES.
AREA OF CONVECTION CROSSING THE LOWER OH VALLEY AND CENTRAL
APPALACHIANS DRIFTING ESE WHILE INDIVIDUAL CELLS MOVING EAST.
MODELS VERIFYING POORLY WITH THIS SYSTEM THOUGH LATEST HRRR RADAR
PROJECTION NOT TOO BAD WITH ITS RENDITION AT 03Z. THE RAPID REFRESH
MODEL BRINGS SCATTERED SHOWERS CLOSE TO OUR NW COUNTIES BETWEEN
9Z-12Z. THIS MODEL MAY BE ONTO SOMETHING AS 00Z ANALYSIS DEPICTS
BEST 850MB THETA E ADVECTION ACROSS THE TN AND LOWER OH
VALLEY...EXTENDING EWD INTO VA. THIS SUGGEST A FEW SHOWERS MAY SKIRT
OUR FAR NRN COUNTIES EARLY WED. THUS HAVE INTRODUCED A
SLIGHT/SMALL CHANCE POP ACROSS THIS REGION EARLY WED.
THIS SFC FEATURE MAY END UP BEING A FOCUS FOR ADDITIONAL CONVECTIVE
DEVELOPMENT WEDNESDAY AFTERNOON. MID LEVEL LAPSE RATES PROJECTED TO
BE NEAR 7 DEG C WHILE SFC BASED CAPE CLOSE TO 1000 J/KG BY MID-LATE
AFTERNOON. WOULD NOT BE SURPRISED TO SEE SOME HAIL WITH THE STRONGER
STORMS WITH MARGINALLY SEVERE HAIL POSSIBLE. DAMAGING WIND THREAT
APPEARS WEAK AT THIS TIME. HAVE ADJUSTED SKY FORECAST AS WELL AS
EXTEND POPS A LITTLE FARTHER A SOUTH WEDNESDAY AFTERNOON AS
SCATTERED SHOWERS AND STORMS WILL LIKELY DRIFT SEWD. NOT EXPECTING
MUCH ACTIVITY TOO FAR SOUTH OF HIGHWAY 64 AS MODEL SOUNDINGS SUGGEST
MID LEVEL CAP WILL HOLD IN THIS REGION. DO NOT ADJUST MAX TEMPS BUT
IF CLOUD OR SHOWER COVERAGE MORE EXTENSIVE THAN CURRENT
THINKING...MAX TAMPS ACROSS THE NW AND FAR NORTHERN PIEDMONT MAY
NEED TO BE ADJUSTED DOWN A FEW DEGREES. -WSS
GOOD RADIATIONAL COOLING AGAIN WED NIGHT...WITH AREAS OF RADIATION
FOG...AND NEAR PERSISTENCE LOWS IN THE MIDDLE TO UPPER 50S. -MWS
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM TUESDAY...
UPPER RIDGE AXIS SHIFTS OFFSHORE AND SURFACE RIDGING WEAKENS ON
THURSDAY. PLENTY OF SUN AND SOUTHERLY FLOW WILL ALLOW HIGHS TO REACH
THE LOWER 80S..BUT LACK OF FORCING AND A LINGERING CAP ALOFT WILL
PRECLUDE CONVECTION OF SIGNIFICANCE. FLOW WILL GRADUALLY VEER AS THE
RIDGING CONTINUES TO WEAKEN OVERNIGHT AND SCATTERED SHOWERS ARE
POSSIBLE IN THE WEST WITH UPSLOPE COMPONENT AND INCREASING MOISTURE
ADVECTION. CLOUDINESS AND WARM ADVECTION WILL INHIBIT DIURNAL
TEMPERATURE CRASH AND MINS WILL BE MILD...AROUND 60.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM TUESDAY...
A STRONG COLD FRONT WILL BE APPROACHING FROM THE WEST AND MOVING
RATHER SLOWLY ACROSS THE STATE ON FRIDAY. THE PARENT LOW WILL BE
WELL TO THE NORTH AND LIFTING QUICKLY NORTHEAST. TIMING WILL BE
FAVORABLE AND TEMPERATURES WILL GET OFF TO A WARM START BUT WITH
LIMITED INSOLATION...ESPECIALLY WEST. THIS SOMEWHAT LIMITED
INSTABILITY COULD BE THE MAJOR INHIBITING FACTOR AS ELEMENTS
FAVORABLE FOR STRONGER TO SEVERE CONVECTION WILL BE FAIRLY
WELL-ALIGNED IN THE LATE DAY TO EARLY OVERNIGHT AS TO MAXIMIZE DEEP
LIFT. WILL INCREASE POPS FROM CHANCE IN THE WEST EARLY TO LIKELY IN
THE AFTERNOON...WITH LIKELY POPS MIGRATING INTO THE EAST OVERNIGHT
BEFORE TAPERING OFF BY SATURDAY MORNING. HIGHS ON FRIDAY WILL TOP
OUT IN THE MID 70S WEST TO LOWER 80S EAST. COLD AIR ADVECTION WILL
GET UNDERWAY AFTER MIDNIGHT WITH MINS FALLING TO THE UPPER 40S WEST
TO LOW AND MID 50S EAST.
HIGH PRESSURE BUILDING UP THE OHIO VALLEY WILL PROVIDE US WITH A DRY
SOMEWHAT COOLER THAN SEASONABLE WEEKEND. HIGHS SATURDAY AND SUNDAY
WILL BE IN THE 60S...SUNDAY MORNINGS LOW WILL BE IN THE 40S.
THE FRONT THAT PASSED OFFSHORE ON SATURDAY MORNING WILL BE LINGERING
ALONG THE COAST AND IS PROGGED TO RETROGRESS TOWARDS THE COAST
MONDAY WITH AN INVERTED TROF ALONG THE COAST EDGING UP AGAINST THE
COOL RIDGE. THIS WILL REINFORCE COOL AIR WITH GOOD NORTHEAST FLOW
AND POSSIBLY SOME SHOWERS ON TUESDAY. HIGHS MONDAY AND TUESDAY WILL
BE MOSTLY IN THE MID TO UPPER 60S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 130 AM WEDNESDAY...
WHILE ITS NOT A NON-ZERO THREAT...THE POTENTIAL FOR WIDESPREAD
FOG AND/OR STRATUS DEVELOPMENT OVERNIGHT LOOKS TO BE ON THE
DECREASE...OWING TO A NOCTURNAL 30KT LOW-LEVEL JET JUST OFF THE
SURFACE PER KRAX VWP. ANOTHER FACTOR THAT WILL DETER WIDESPREAD
FOG/STRATUS DEVELOPMENT WILL BE THE INCREASE IN MID AND HIGH LEVEL
DEBRIS CLOUD COVER FROM THE NORTH/NORTHWEST AS A WEAKENING LINE OF
CONVECTION PROGRESSES EASTWARD OFF THE MOUNTAINS OF WEST VA. AS
SUCH...OUTSIDE OF PATCHY FOG AT KRWI AND KFAY...WILL HAVE
PREDOMINATELY VFR CONDITIONS THROUGH THE TAF PERIOD. HOWEVER THERE
IS CHANCE THAT SOME ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS COULD IMPACT NORTH/NORTHWESTERN TERMINALS THIS
AFTERNOON.
LOOKING AHEAD: MORNING FOG/STRATUS WILL POSE A THREAT THURSDAY
MORNING AND AGAIN FRIDAY MORNING. OTHERWISE EXPECT VFR CONDITIONS
UNTIL THE ARRIVAL OF A COLD FRONT AND PRECEDING SHOWERS AND STORMS
FRI-FRI NIGHT. VFR CONDITIONS IN ASSOCIATED WITH SURFACE HIGH
PRESSURE RETURN FOR THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...WSS/MWS
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
432 AM EDT WED APR 17 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS THE REGION
TODAY...LIFTING NORTH OF THE REGION AS A WARM FRONT BY TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. WARM SOUTHERLY FLOW WILL
EXIST OVER THE REGION ON THURSDAY...BEFORE A STRONG COLD FRONT
BRINGS SHOWERS AND STORMS (AND MUCH COLDER TEMPERATURES) EARLY
FRIDAY MORNING. COOLER CONDITIONS ARE EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THUNDER CONTINUES TO RUMBLE ACROSS THE REGION EARLY THIS
MORNING...PARTICULARLY ACROSS THE IND AND ILN FORECAST AREAS.
CONVECTION IS REPEATEDLY DEVELOPING ON THE COOL SIDE OF THE
SURFACE BOUNDARY...AIDED BY QUITE A BIT OF CONVERGENCE AND
MOISTURE TRANSPORT JUST OFF THE SURFACE. THIS FORCING WAS TOUGH TO
PICK OUT...AS IT APPEARS TO BE WITHIN A LAYER OF SOUTHWESTERLY
FLOW FROM JUST OFF THE SURFACE TO AROUND 875MB. WINDS AT 850MB
AND ABOVE ARE MORE WESTERLY THAN SOUTHWESTERLY.
ALL SIGNS (QPF OUTPUT...HIGH-RES SIMULATED REFLECTIVITY...AND A
WEAKENING TO THE SOUTHWESTERLY FLOW) POINT TOWARD A GRADUAL
WEAKENING TREND LATER IN MORNING HOURS. HOWEVER...THE ACTIVITY IS
EXPECTED TO PERSIST FOR THE NEXT SEVERAL HOURS AT LEAST...AND THE
RECENT HRRR RUNS ARE FINALLY PICKING UP ON THIS A BIT (THOUGH THEY
SEEM TO MOVE THE CONVECTION ON TOO SOUTHERLY A TRAJECTORY). POPS
ARE VERY HIGH (AS HIGH AS 100 PERCENT) DURING THE EARLY
MORNING...BEFORE DIMINISHING SIGNIFICANTLY BY LATE MORNING AND
AFTERNOON.
THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH LATER TODAY...BUT IT
IS NOT AS WELL DEFINED AS IT WAS YESTERDAY. SUPPORT FOR FORCING IS
ALSO NOT ESPECIALLY STRONG...AS 500MB HEIGHTS RISE.
THEREFORE...CONVECTION IS NOT EXPECTED TO BE AS WIDESPREAD AS IT
WAS ON TUESDAY...NOR WILL IT BE LIKELY TO BE AS STRONG. THERE
SHOULD BE ENOUGH INSTABILITY ALONG AND SOUTH OF THE BOUNDARY TO
SUPPORT A LOW-END SEVERE THREAT...BUT SHEAR IS NOT IMPRESSIVE
(20-30 KNOTS 0-6KM...PERHAPS EVEN LESS IN THE FAR SOUTH).
TEMPERATURE LEVELS WILL ALSO BE RISING A BIT FROM WHERE THEY ARE
AT NOW (AND WHERE THEY WERE LAST EVENING). SO...THE HWO WILL
INCLUDE A HEDGED MENTION...AS SEVERE WEATHER LOOKS UNLIKELY BUT
NOT TOTALLY IMPOSSIBLE.
TEMPS WERE NOT EASY TODAY...GIVEN THE ABUNDANCE OF CLOUDS AND THE
TOUGH FORECAST FOR THE LOCATION OF THE BOUNDARY. TEMPS WERE KEPT
CLOSE TO GUIDANCE...THOUGH COOLER THAN THE RAW NAM12. THE GRADIENT
ACROSS THE CWA IS TIGHT...WITH UPPER 70S IN THE FAR SOUTH AND MID
60S IN THE FAR NORTH. DEPENDING ON HOW SLOW THE MORNING CONVECTION
DISSIPATES...THERE COULD BE BUST POTENTIAL WITH THESE NUMBERS
BEING TOO HIGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL BE NORTH OF THE REGION BY WEDNESDAY
NIGHT...WITH THE CWA UNDER A MID-LEVEL RIDGE AND ENTERING A REGIME
OF SOUTHERLY FLOW. THIS SHOULD LOCK MOST OF THE CWA (ALL BUT THE
NORTHWEST CORNER) IN THE WARM SECTOR...HELPING TO SIGNIFICANTLY
DIMINISH CHANCES OF PRECIPITATION THROUGH THE DAY ON THURSDAY.
WHILE SOME DIURNAL CONVECTION MAY BE POSSIBLE AT THE NORTH AND
WEST FRINGES OF THE CWA ON THURSDAY AFTERNOON...A LACK OF FORCING
AND PERHAPS SOME CAPPING WILL LIMIT THIS POTENTIAL. THE
SOUTHEASTERN HALF OF THE CWA SHOULD ALMOST CERTAINLY REMAIN DRY.
AS THE SOUTHWESTERLY FLOW INCREASES...AND CONDITIONS MIX RATHER
WELL ON THURSDAY...WIND GUSTS INTO THE 30-40 MPH RANGE APPEAR
POSSIBLE. IN FACT...BOTH THE GFS/NAM ARE SHOWING GUSTS AS HIGH AS
45 MPH ON BUFKIT IN THE FAR NORTH (NEAR LIMA OH). WITH THE STRONG
WARM ADVECTION...THE MAX TEMP FORECAST FOR THURSDAY REMAINS WELL
ABOVE NORMAL...WITH MID 80S IN THE SOUTHEAST PART OF THE CWA.
MODELS APPEAR TO BE IN VERY GOOD AGREEMENT ON THE BIG CONCLUSION
TO THE UNSETTLED WEATHER THIS WEEK. LOW PRESSURE IS FORECAST TO
MOVE NORTHEAST TOWARD CHICAGO BY THURSDAY NIGHT...AND THEN ONWARD
TO THE STRAITS OF MACKINAC BY FRIDAY MORNING. A STRONG COLD FRONT
WILL MOVE EASTWARD THROUGH THE MISSISSIPPI VALLEY THURSDAY
EVENING...AND THEN THROUGH THE OHIO VALLEY INTO THE ILN CWA BY
EARLY FRIDAY MORNING.
SPC HAS PLACED A LARGE AREA INTO A HIGH-END SLIGHT
RISK ON DAY2. THIS RISK AREA IS GENERALLY ALONG AND AHEAD OF THE
EXPECTED POSITION OF THE COLD FRONT...AS IT PROGRESSES FROM THE
AFTERNOON INTO THE EARLY OVERNIGHT HOURS ON THURSDAY. THERE IS NO
QUESTION THAT THE BEST SEVERE POTENTIAL IS WEST OF THE ILN
CWA...WHERE DIURNAL INSTABILITY WILL BE GREATEST. HOWEVER...SHEAR
WILL CONTINUE TO BE VERY STRONG EVEN THROUGH THE OVERNIGHT HOURS
AND INTO FRIDAY MORNING. FLOW AT ALL LEVELS WILL INCREASE AHEAD OF
THE FRONT...WITH A LOW-LEVEL JET OF 60-70 KNOTS AT 850MB NEAR 06Z.
INSTABILITY WILL BE THE POTENTIAL LIMITING FACTOR FOR SEVERE
WEATHER...GIVEN UNFAVORABLE NEAR-SURFACE THERMODYNAMIC PROFILES AT
THE TIME THE WEAKENING FRONTAL CONVECTION IS MOVING INTO THE CWA.
AT THEIR MOST FAVORABLE...SOME OF THE MODEL SOUNDINGS ARE ROUGHLY
MOIST-ADIABATIC...WHILE OTHERS DISPLAY MORE OF A SLIGHTLY-INVERTED
PROFILE.
THIS SCENARIO WILL BE CLOSELY MONITORED OVER THE NEXT FEW
DAYS...AS THE STRONG WIND FIELDS MEAN THAT SEVERE WEATHER COULD BE
POSSIBLE EVEN WITH THE UNFAVORABLE TIMING. EVEN ASIDE FROM THE
CONVECTIVE POTENTIAL...BUFKIT SOUNDINGS ARE INDICATING WIND GUSTS
OF 25-30 KNOTS BEHIND THE FRONT. THE PROGRESSIVE NATURE OF THE
FRONT WILL LIKELY LIMIT ANY POTENTIAL FLOODING ISSUES...BUT THE
MOISTURE TRANSPORT APPEARS TO BE VERY STRONG...AND RAINFALL
AMOUNTS OF OVER AN INCH WILL BE POSSIBLE (ESPECIALLY IN THE
WESTERN HALF OF THE CWA).
NON-DIURNAL TEMPS WERE DRAWN IN FOR FRIDAY...WITH MAX TEMPS
EXPECTED IN THE MORNING...AND A SIGNIFICANT DECREASE BEHIND THE
FRONT. AS AN EXAMPLE OF THE EXPECTED CHANGE IN AIR MASS...NAM12
850MB TEMPS AT KILN ARE FORECAST TO GO FROM +14C AT 06Z FRIDAY
MORNING TO -5C JUST 24 HOURS LATER.
BEHIND THE FRONT...LOW LEVEL MOISTURE IS EXPECTED TO BE VERY SLOW
TO SCOUR OUT. SOME TROUGHING ALOFT WILL BRING A SLIGHT CHANCE OF
SHOWERS TO THE NORTHERN CWA ON FRIDAY AFTERNOON...BUT A LACK OF
DEEPER MOISTURE IS LIMITING QPF AMOUNTS TO JUST A FEW HUNDREDTHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRESSURE AND DRY AIR WILL BUILD IN FOR SATURDAY THROUGH MONDAY.
ANOTHER STRONG COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
AFTER A MORNING HIGH NEAR 60 ON FRIDAY...HIGHS WILL BE MAINLY IN THE
50S SATURDAY AND SUNDAY. A REBOUND BACK INTO THE 60S IS INDICATED
FOR MONDAY AND TUESDAY AS WARM ADVECTION OCCURS IN THE RETURN FLOW
OF HIGH PRESSURE. TO COINCIDE WITH THE START OF OUR FROST/FREEZE
PROGRAM FOR THE ENTIRE ILN AREA...FROST WILL BE POSSIBLE SUNDAY
MORNING WHEN TEMPERATURES ARE FORECAST TO FALL TO THE LOWER TO
MIDDLE 30S.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT NEAR THE OHIO RIVER THIS MORNING WILL
MOVE SLOWLY BACK NORTH AS A WARM FRONT TODAY...AND WILL LIFT INTO
THE SOUTHERN GREAT LAKES TONIGHT.
COMPLEX TAF PROBLEM THIS MORNING GIVEN AMPLE LOW LEVEL MOISTURE
AND ONGOING ELEVATED CONVECTION. AN EMBEDDED WEATHER DISTURBANCE
WILL RIDE WEST TO EAST ALONG AFOREMENTIONED STATIONARY FRONT THIS
MORNING. THIS WILL KEEP THE THREAT FOR SHOWERS AND THUNDERSTORMS
GOING THROUGH DAYBREAK...BUT WITH ACTIVITY AND COVERAGE DECREASING
BY THEN AS WELL. PREVIOUS CONVECTION FROM THE AFTERNOON AND
EVENING ON TUESDAY HAS PROVIDED AMPLE LOW LEVEL MOISTURE...AND ON
THE COOL SIDE OF THE BOUNDARY...LOW STRATUS HAS FORMED. THUS...AM
EXPECTING CIGS TO BE NEAR OR BELOW ALTERNATE MINS AT THE TAF SITES
OUTSIDE OF CONVECTION...WHICH IN THE CONVECTION ITSELF...CIGS MAY
ACTUALLY TEMPORARILY LIFT TO MVFR DUE TO MIXING. VSBYS WILL BE
MVFR WITH IFR VSBYS POSSIBLE IN HEAVIER PCPN.
FOR LATER THIS MORNING AND THIS AFTN...FRONTAL BOUNDARY WILL BE
SLOW TO MOVE NORTH AND AS SUCH IT WILL TAKE SOME TIME FOR LOW
LEVEL MOISTURE TO MIX INTO A LOW VFR CUMULUS DECK. AM HAVING A
HARD TIME FINDING ANY SUPPLEMENTAL TRIGGERING MECHANISMS FOR
SHOWERS AND STORMS OTHER THAN THE FRONTAL BOUNDARY ITSELF THIS
AFTERNOON SO HAVE KEPT A MENTION OF VCTS/CB AT THE SRN/WRN TAF
SITES WHERE THREAT IS THE HIGHEST.
FOR TONIGHT...LARGE SCALE MID LVL TROUGH WILL PUSH EAST INTO THE
PLAINS. THIS WILL ALLOW THE MID LVL FLOW TO BUCKLE AS WARM FRONT
ADVANCES NORTH INTO THE SOUTHERN GREAT LAKES. SOME MODELS SUGGEST
THAT SOME CONVECTION COULD GRAZE OUR WESTERN FORECAST AREA EARLY
ON..BUT CONFIDENCE IN THIS IS LOW ATTM SO HAVE MAINTAINED A DRY
FORECAST. OTHERWISE...VFR CONDITIONS ARE EXPECTED OVERNIGHT.
OUTLOOK...GUSTY SOUTH/SOUTHWEST WINDS TO 30 KNOTS ON THURSDAY.
SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
409 AM EDT WED APR 17 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS THE REGION
TODAY...LIFTING NORTH OF THE REGION AS A WARM FRONT BY TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. WARM SOUTHERLY FLOW WILL
EXIST OVER THE REGION ON THURSDAY...BEFORE A STRONG COLD FRONT
BRINGS SHOWERS AND STORMS (AND MUCH COLDER TEMPERATURES) EARLY
FRIDAY MORNING. COOLER CONDITIONS ARE EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THUNDER CONTINUES TO RUMBLE ACROSS THE REGION EARLY THIS
MORNING...PARTICULARLY ACROSS THE IND AND ILN FORECAST AREAS.
CONVECTION IS REPEATEDLY DEVELOPING ON THE COOL SIDE OF THE
SURFACE BOUNDARY...AIDED BY QUITE A BIT OF CONVERGENCE AND
MOISTURE TRANSPORT JUST OFF THE SURFACE. THIS FORCING WAS TOUGH TO
PICK OUT...AS IT APPEARS TO BE WITHIN A LAYER OF SOUTHWESTERLY
FLOW FROM JUST OFF THE SURFACE TO AROUND 875MB. WINDS AT 850MB
AND ABOVE AE MORE WESTERLY THAN SOUTHWESTERLY.
ALL SIGNS (QPF OUTPUT...HIGH-RES SIMULATED REFLECTIVITY...AND A
WEAKENING TO THE SOUTHWESTERLY FLOW) POINT TOWARD A GRADUAL
WEAKENING TREND LATER IN MORNING HOURS. HOWEVER...THE ACTIVITY IS
EXPECTED TO PERSIST FOR THE NEXT SEVERAL HOURS AT LEAST...AND THE
RECENT HRRR RUNS ARE FINALLY PICKING UP ON THIS A BIT (THOUGH THEY
SEEM TO MOVE THE CONVECTION ON TOO SOUTHERLY A TRAJECTORY). POPS
ARE VERY HIGH (AS HIGH AS 100 PERCENT) DURING THE EARLY
MORNING...BEFORE DIMINISHING SIGNIFICANTLY BY LATE MORNING AND
AFTERNOON.
THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH LATER TODAY...BUT IT
IS NOT AS WELL DEFINED AS IT WAS YESTERDAY. SUPPORT FOR FORCING IS
ALSO NOT ESPECIALLY STRONG...AS 500MB HEIGHTS RISE.
THEREFORE...CONVECTION IS NOT EXPECTED TO BE AS WIDESPREAD AS IT
WAS ON TUESDAY...NOR WILL IT BE LIKELY TO BE AS STRONG. THERE
SHOULD BE ENOUGH INSTABILITY ALONG AND SOUTH OF THE BOUNDARY TO
SUPPORT A LOW-END SEVERE THREAT...BUT SHEAR IS NOT IMPRESSIVE
(20-30 KNOTS 0-6KM...PERHAPS EVEN LESS IN THE FAR SOUTH).
TEMPERATURE LEVELS WILL ALSO BE RISING A BIT FROM WHERE THEY ARE
AT NOW (AND WHERE THEY WERE LAST EVENING). SO...THE HWO WILL
INCLUDE A HEDGED MENTION...AS SEVERE WEATHER LOOKS UNLIKELY BUT
NOT TOTALLY IMPOSSIBLE.
TEMPS WERE NOT EASY TODAY...GIVEN THE ABUNDANCE OF CLOUDS AND THE
TOUGH FORECAST FOR THE LOCATION OF THE BOUNDARY. TEMPS WERE KEPT
CLOSE TO GUIDANCE...THOUGH COOLER THAN THE RAW NAM12. THE GRADIENT
ACROSS THE CWA IS TIGHT...WITH UPPER 70S IN THE FAR SOUTH AND MID
60S IN THE FAR NORTH. DEPENDING ON HOW SLOW THE MORNING CONVECTION
DISSIPATES...THERE COULD BE BUST POTENTIAL WITH THESE NUMBERS
BEING TOO HIGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
(UPDATED SHORT TERM DISCUSSION COMING SOON)
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
STRONG COLD FRONT WILL BE EXITING TO THE EAST ON FRIDAY. SHOWERS
AND THUNDERSTORMS WILL BE ENDING FROM EAST TO WEST. HIGH
TEMPERATURES WILL PROBABLY OCCUR IN THE MORNING WITH COLDER AIR
RUSHING IN ON A BRISK WESTERLY FLOW BEHIND THE FRONT.
HIGH PRESSURE AND DRY AIR WILL BUILD IN FOR SATURDAY THROUGH MONDAY.
ANOTHER STRONG COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
AFTER A MORNING HIGH NEAR 60 ON FRIDAY...HIGHS WILL BE MAINLY IN THE
50S SATURDAY AND SUNDAY. A REBOUND BACK INTO THE 60S IS INDICATED
FOR MONDAY AND TUESDAY AS WARM ADVECTION OCCURS IN THE RETURN FLOW
OF HIGH PRESSURE. TO COINCIDE WITH THE START OF OUR FROST/FREEZE
PROGRAM FOR THE ENTIRE ILN AREA...FROST WILL BE POSSIBLE SUNDAY
MORNING WHEN TEMPERATURES ARE FORECAST TO FALL TO THE LOWER TO
MIDDLE 30S.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT NEAR THE OHIO RIVER THIS MORNING WILL
MOVE SLOWLY BACK NORTH AS A WARM FRONT TODAY...AND WILL LIFT INTO
THE SOUTHERN GREAT LAKES TONIGHT.
COMPLEX TAF PROBLEM THIS MORNING GIVEN AMPLE LOW LEVEL MOISTURE
AND ONGOING ELEVATED CONVECTION. AN EMBEDDED WEATHER DISTURBANCE
WILL RIDE WEST TO EAST ALONG AFOREMENTIONED STATIONARY FRONT THIS
MORNING. THIS WILL KEEP THE THREAT FOR SHOWERS AND THUNDERSTORMS
GOING THROUGH DAYBREAK...BUT WITH ACTIVITY AND COVERAGE DECREASING
BY THEN AS WELL. PREVIOUS CONVECTION FROM THE AFTERNOON AND
EVENING ON TUESDAY HAS PROVIDED AMPLE LOW LEVEL MOISTURE...AND ON
THE COOL SIDE OF THE BOUNDARY...LOW STRATUS HAS FORMED. THUS...AM
EXPECTING CIGS TO BE NEAR OR BELOW ALTERNATE MINS AT THE TAF SITES
OUTSIDE OF CONVECTION...WHICH IN THE CONVECTION ITSELF...CIGS MAY
ACTUALLY TEMPORARILY LIFT TO MVFR DUE TO MIXING. VSBYS WILL BE
MVFR WITH IFR VSBYS POSSIBLE IN HEAVIER PCPN.
FOR LATER THIS MORNING AND THIS AFTN...FRONTAL BOUNDARY WILL BE
SLOW TO MOVE NORTH AND AS SUCH IT WILL TAKE SOME TIME FOR LOW
LEVEL MOISTURE TO MIX INTO A LOW VFR CUMULUS DECK. AM HAVING A
HARD TIME FINDING ANY SUPPLEMENTAL TRIGGERING MECHANISMS FOR
SHOWERS AND STORMS OTHER THAN THE FRONTAL BOUNDARY ITSELF THIS
AFTERNOON SO HAVE KEPT A MENTION OF VCTS/CB AT THE SRN/WRN TAF
SITES WHERE THREAT IS THE HIGHEST.
FOR TONIGHT...LARGE SCALE MID LVL TROUGH WILL PUSH EAST INTO THE
PLAINS. THIS WILL ALLOW THE MID LVL FLOW TO BUCKLE AS WARM FRONT
ADVANCES NORTH INTO THE SOUTHERN GREAT LAKES. SOME MODELS SUGGEST
THAT SOME CONVECTION COULD GRAZE OUR WESTERN FORECAST AREA EARLY
ON..BUT CONFIDENCE IN THIS IS LOW ATTM SO HAVE MAINTAINED A DRY
FORECAST. OTHERWISE...VFR CONDITIONS ARE EXPECTED OVERNIGHT.
OUTLOOK...GUSTY SOUTH/SOUTHWEST WINDS TO 30 KNOTS ON THURSDAY.
SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
422 AM CDT WED APR 17 2013
.DISCUSSION...
FRONTAL BOUNDARY HAS BEGUN TO SLOWLY LIFT NORTH AS A WARM FRONT
AND THE NORTHWARD PROGRESS OF THIS FRONT SHOULD ACCELERATE OVER
THE NEXT FEW HOURS WITH THE ENTIRE FORECAST AREA IN THE WARM
SECTOR BY LATER THIS MORNING. CONVECTIVE EVOLUTION TODAY IS
UNCLEAR WITH A MYRIAD OF SOLUTIONS DEPICTED BY THE VARIOUS MODELS.
LARGE SCALE HEIGHT FALLS WILL BEGIN THIS MORNING AHEAD OF THE
UPPER SYSTEM CURRENTLY IN UTAH AND THIS SHOULD RESULT IN A
WEAKENING OF THE CAP. SEVERAL MODELS INCLUDING THE HRRR DEPICT A
GRADUAL UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY THIS
MORNING...MAINLY ACROSS NORTHEAST OKLAHOMA. WILL CARRY THE HIGHEST
POPS IN THIS AREA TODAY WITH MUCH LOWER POPS TO THE SOUTH. ANY
STORMS THAT REMAIN DISCRETE TODAY WILL CARRY A HIGH SEVERE
POTENTIAL.
CONVECTIVE COVERAGE WILL INCREASE OVERNIGHT AS THE UPPER SYSTEM
AND ASSOCIATED COLD FRONT APPROACH THE AREA. A SQUALL LINE WILL
EVENTUALLY DEVELOP ALONG THE COLD FRONT AND SWEEP ACROSS THE AREA
OVERNIGHT. SHOWERS AND STORMS WILL LINGER BEHIND THE FRONT BUT THE
LATEST DATA SUPPORT A QUICKER EXIT TO THE RAIN THURSDAY. THIS
SHOULD ALLOW FOR SOME TEMPERATURE RECOVERY THURSDAY AFTERNOON.
TOTAL RAINFALL AMOUNTS FROM THIS SYSTEM MAY BE NEAR 3 INCHES IN
SOME PLACES...MAINLY IN THE NORTH...SO WILL HAVE TO WATCH THE
FLOODING POTENTIAL ESPECIALLY OVERNIGHT INTO THURSDAY MORNING.
TEMPERATURES WILL DROP TO NEAR OR BELOW FREEZING IN MANY PLACES
THURSDAY NIGHT WITH SOME PLACES LIKELY SEEING THEIR COLDEST
READINGS RECORDED FOR SO LATE IN THE SEASON. APRIL 15TH IS THE
LATESE FREEZE ON RECORD IN MCALESTER AND TULSA HAS NEVER BEEN
COLDER THAN 32 AFTER APRIL 18TH DURING THE PERIOD OF RECORD. A
WARMING TREND WILL TAKE PLACE OVER THE WEEKEND BUT ANOTHER STRONG
COLD FRONT IS SET TO MOVE THROUGH THE AREA EARLY NEXT WEEK. THE
LATEST DATA SUPPORTS A SLOWER FRONTAL PASSAGE SO THE HIGHEST RAIN
CHANCES WILL BE MONDAY NIGHT AND TUESDAY. TEMPERATURES BEHIND THIS
FRONT MAY ONCE AGAIN FLIRT WITH THE FREEZING MARK IN SOME PLACES
BY NEXT WEDNESDAY MORNING.
MADE SOME SIGNIFICANT ADJUSTMENTS TO GUIDANCE TEMPERATURES AGAIN
FOR TONIGHT AND THURSDAY BASED ON THE FORECAST FRONTAL MOVEMENT
AND THE VERIFICATION CUTOFF TIMES...WITH THE SIMILAR ECMWF AND NAM
FOLLOWED ON FRONTAL TIMING.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 78 43 54 32 / 60 90 50 10
FSM 84 53 65 35 / 30 60 80 10
MLC 81 45 56 32 / 30 70 60 10
BVO 76 40 52 29 / 70 90 40 10
FYV 79 49 56 29 / 40 70 80 10
BYV 80 62 65 30 / 40 60 80 10
MKO 80 45 55 32 / 50 80 70 10
MIO 78 43 52 31 / 70 90 70 10
F10 79 43 55 32 / 40 90 60 10
HHW 83 52 61 36 / 30 60 80 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...23
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1017 PM MDT TUE APR 16 2013
.UPDATE...
ISSUED AT 802 PM MDT TUE APR 16 2013
02Z SURFACE ANALYSIS HAD LOW PRESSURE OVER SOUTH CENTRAL CO WITH
INVERTED TROUGH INTO SOUTHEAST MT. 00Z UPPER AIR ANALYSIS HAD
110KT JET STREAK FROM NORTH CENTRAL CO INTO NORTHWEST SD WITH THE
RIGHT ENTRANCE REGION OF JET RESPONSIBLE FOR BURST OF SN NOW SHIFTING
EAST OF THE BLACK HILLS INTO CENTRAL PORTIONS OF SD. 2-4 INCHES
FELL SOUTHWEST SD...SEE LOCAL STORM REPORTS. RATHER STRONG
850-700MB FRONTOGENESIS NOTED BELOW JET. 00Z RAP DEPICTED FIRST
AREA OF PRECIPITATION DECENTLY...SHIFTING TO THE NORTH AND EAST
THIS EVENING. NEXT IMPULSE APPEARS TO BE OVER SOUTHWEST UT IN LEFT
EXIT REGION OF 100KT JET STREAK PER WATER VAPOUR. THERE MIGHT EVEN
BE AN IMPULSE OVER NORTH CENTRAL CO. ACTIVITY WILL MOVE NORTHEAST
OVERNIGHT BRINGING ANOTHER BURST OR TWO OF MODERATE/HEAVY
SNOW...ESPECIALLY ACROSS SOUTHWEST PORTIONS OF CWA. LATEST
GUIDANCE SUGGESTS 3-6 INCHES ACCUMULATION OVERNIGHT...AND THAT IS
PRETTY CLOSE TO CURRENT FORECAST. WILL LEAVE CURRENT HEADLINES AND
GIST OF FORECAST INTACT...BUT WILL CONTINUE TO WATCH ANY SHIFTS OF
MAIN PRECIPITATION BAND THROUGH THE NIGHT.
&&
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 228 PM MDT TUE APR 16 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER SOUTHWESTERLY COLORADO
WITH HIGH OVER THE MIDWEST. UPPER LEVEL ANALYSIS PLACES DEEP TROF
OVER THE WESTERN CONUS STRETCHING FROM THE NORTHERN ROCKIES INTO
THE GREAT BASIN. INITIAL WAVES EJECTING AHEAD TO THE TROF THRU
SWRLY FLOW INTO OUR AREA CONTINUE TO BRING BROAD AREA OF SNOW OVER
MUCH OF THE CWA. ACCUMULATIONS HAVE BEEN REPORTED OVER THE SWRN
CWA...THOUGH OVER THE SODAK PLAINS SNOW CONTINUES TO MELT ON
ROADWAYS.
FOR TONIGHT...TROF CONTINUES TO DEEPEN AND STARTS TO SLOWLY SHIFT
TO THE EAST. AS IT DOES...BROAD SCALE LIFT DEVELOPS OVER THE AREA
BRINGING INCREASING SNOWFALL RATES. WITH THIS ALONG WITH LACK OF
INSOLATION...EXPECT SNOW TO START ACCUMULATING OVER REMAINING PTNS
OF THE SODAK PLAINS LATE THIS AFT INTO EARLY THIS EVE. SOME
UPSLOPE ENHANCEMENT MAY DEVELOP OVER THE ERN FOOTHILLS WITH
EASTERLY COMPONENT TO LOW LEVEL FLOW POSSIBLY RESULTING IN SOME
LOCALLY HIGHER AMOUNTS.
ON WEDNESDAY...UPPER TROF CONTINUES TO WORK ITS WAY EAST WITH AXIS
STRETCHING FROM SRN SASKATCHEWAN TOWARDS THE FOUR CORNERS REGION BY
LATE AFTERNOON. BROAD SCALE LIFT CONTINUES THROUGH MOST OF THE DAY
WITH SNOW CONTINUING. SFC LOW PUSHES FROM COLORADO INTO THE PLAINS
WITH PRESSURE GRADIENT TIGHTEN SOME OVER OUR AREA BRINGING BREEZY
CONDITIONS ALONG WITH SOME BLOWING/DRIFTING SNOW. BY LATE
AFTERNOON INTO THE EVENING...TROF AXIS WILL SLOWLY WORK ITS WAY
EAST INTO THE CWA WITH RIDGING QUICKLY DEVELOPING IN ITS WAKE.
SNOW WILL THEN SLOWLY START DIMINISHING FROM WEST TO EAST...LINGERING
OVER SOUTH CENTRAL SD INTO THE MORNING.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 228 PM MDT TUE APR 16 2013
WINTER STORM WILL EXIT THE REGION WEST TO EAST ON THURSDAY WITH
LINGERING SNOW POSSIBLE ACROSS SOUTH CENTRAL SD THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS ARE EXPECTED THURSDAY NIGHT AND FRIDAY AS
A SHORT WAVE RIDGE CROSSES THE NORTHERN PLAINS. A FEW NORTHERN
STREAM WAVES WILL CROSS THE REGION FRIDAY NIGHT THROUGH
MONDAY...BRINGING ADDITIONAL CHANCES FOR LIGHT PRECIPITATION.
TEMPERATURES WILL REMAIN WELL BELOW AVERAGE THROUGH THE EXTENDED
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1015 PM MDT TUE APR 16 2013
WIDESPREAD IFR/LIFR CONDITIONS DUE TO SN WILL CONTINUE THROUGH
WEDNESDAY AFTERNOON ACROSS MUCH OF THE. CONDITIONS WILL SLOWLY
IMPROVE WEDNESDAY EVENING AS HEAVIEST SNOWS PUSHES EAST.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
SDZ024>032-041-042-072>074.
WINTER STORM WARNING UNTIL 6 AM MDT /7 AM CDT/ THURSDAY FOR
SDZ043-044-046-047-049.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
SDZ012>014.
WY...WINTER STORM WARNING UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
WYZ054>058.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT WEDNESDAY NIGHT FOR
WYZ071.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...15
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1211 AM CDT WED APR 17 2013
.DISCUSSION...
THIS MODEL RUN CONTINUES TO BRING MVFR CEILINGS BACK TO WEST
CENTRAL TEXAS DURING THE NEXT SEVERAL HOURS. SEE AVIATION BELOW
FOR MORE INFORMATION.
&&
.AVIATION...
MODELS THIS CYCLE INDICATE LITTLE NEED FOR CHANGES TO THE
TERMINALS. I DID ADJUST THE ONSET TIMING OF THE STRATUS BASED ON
SATELLITE DATA. HOWEVER...I STILL ANTICIPATE MVFR CEILINGS ACROSS
ALL OF WEST CENTRAL TEXAS BY 12Z TOMORROW MORNING. FLIGHT WEATHER
CONDITIONS SHOULD RETURN TO VFR BY 18Z...AS MIXING OF DRIER AIR
ALOFT BREAKS THE STRATUS CEILING. AS FOR THUNDERSTORMS TOMORROW
AFTERNOON AND EVENING...THE NAM AND GFS THIS CYCLE CONTINUE TO
SHOW DIFFERENT SOLUTIONS. THE NAM IS DRY UNTIL AFTER 06Z TOMORROW
NIGHT...WHILE THE GFS DOES INDICATE POSSIBLE CONVECTION ACROSS THE
BIG COUNTRY BETWEEN 00 AND 06Z. GIVEN THESE DIVERGING SOLUTIONS...I
DECIDED TO NOT INCLUDE ANY THUNDER IN ANY OF THE TERMINALS THIS
CYCLE.
HUBER
&&
.PREV DISCUSSION... /ISSUED 1148 PM CDT TUE APR 16 2013/
DISCUSSION...
HAVE REMOVED MENTION OF PRECIPITATION FROM THE FORECAST. WE MAY
SEE SOME LIGHT DRIZZLE OR FOG NORTH OF INTERSTATE 20 LATER TONIGHT
NEAR THE STALLED COLD FRONTAL BOUNDARY...BUT NOT EXPECTING ANY
SIGNIFICANT PRECIPITATION TO DEVELOP THROUGH THE REST OF THE
OVERNIGHT HOURS AT THIS TIME. 20
PREV DISCUSSION... /ISSUED 644 PM CDT TUE APR 16 2013/
DISCUSSION...
LOOK FOR CHALLENGING FLIGHT WEATHER CONDITIONS TO DEVELOP ACROSS
WEST CENTRAL TEXAS DURING THE NEXT 6 HOURS. AVIATION BELOW HAS
DETAILS.
AVIATION...
MODELS THIS CYCLE CONTINUE TO INDICATE STRATUS AND MVFR CEILINGS
WILL RETURN TO ALL OF WEST CENTRAL TEXAS BY 06Z TONIGHT. THE NAM
AND GFS 925 MB RELATIVE HUMIDITY FIELDS INCREASE TO NEAR
SATURATION BY 06Z ACROSS ALL OF WEST CENTRAL TEXAS. PLUS...THE GFS
AND NAM MOS GUIDANCE BOTH HOLD MVFR CEILINGS AT ALL FIVE TERMINALS
WELL INTO TOMORROW AFTERNOON. OUR PREVIOUS AVIATION FORECAST
PACKAGE RETURNED VFR CONDITIONS TO ALL FIVE TERMINALS BY 15Z
TOMORROW MORNING. HOWEVER...ALL INDICATORS SUGGEST THE MVFR
CEILINGS WILL LIKELY HOLD UNTIL AROUND 18Z TOMORROW AFTERNOON.
SO...THE NEW TERMINALS HOLD MVFR CEILINGS UNTIL 18Z.
ALSO...A WEAK FRONTAL BOUNDARY HAS STALLED NEAR A SWEETWATER TO
ALBANY LINE. THIS SURFACE BOUNDARY MAY INITIATE SHOWERS AND
THUNDERSTORMS LATER THIS EVENING. HOWEVER...I DECIDED NOT TO
INCLUDE ANY THUNDER IN THE ABILENE TERMINAL BECAUSE MY CONFIDENCE
FOR WHEN AND WHERE THIS CONVECTION MAY INITIATE IS NOT VERY HIGH.
HUBER
PREV DISCUSSION... /ISSUED 340 PM CDT TUE APR 16 2013/
SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 62 36 62 41 / 40 10 5 5 0
SAN ANGELO 58 65 38 67 43 / 30 10 5 5 0
JUNCTION 63 70 39 67 41 / 50 10 5 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1148 PM CDT TUE APR 16 2013
.DISCUSSION...
HAVE REMOVED MENTION OF PRECIPITATION FROM THE FORECAST. WE MAY
SEE SOME LIGHT DRIZZLE OR FOG NORTH OF INTERSTATE 20 LATER TONIGHT
NEAR THE STALLED COLD FRONTAL BOUNDARY...BUT NOT EXPECTING ANY
SIGNIFICANT PRECIPITATION TO DEVELOP THROUGH THE REST OF THE
OVERNIGHT HOURS AT THIS TIME. 20
&&
.PREV DISCUSSION... /ISSUED 644 PM CDT TUE APR 16 2013/
DISCUSSION...
LOOK FOR CHALLENGING FLIGHT WEATHER CONDITIONS TO DEVELOP ACROSS
WEST CENTRAL TEXAS DURING THE NEXT 6 HOURS. AVIATION BELOW HAS
DETAILS.
AVIATION...
MODELS THIS CYCLE CONTINUE TO INDICATE STRATUS AND MVFR CEILINGS
WILL RETURN TO ALL OF WEST CENTRAL TEXAS BY 06Z TONIGHT. THE NAM
AND GFS 925 MB RELATIVE HUMIDITY FIELDS INCREASE TO NEAR
SATURATION BY 06Z ACROSS ALL OF WEST CENTRAL TEXAS. PLUS...THE GFS
AND NAM MOS GUIDANCE BOTH HOLD MVFR CEILINGS AT ALL FIVE TERMINALS
WELL INTO TOMORROW AFTERNOON. OUR PREVIOUS AVIATION FORECAST
PACKAGE RETURNED VFR CONDITIONS TO ALL FIVE TERMINALS BY 15Z
TOMORROW MORNING. HOWEVER...ALL INDICATORS SUGGEST THE MVFR
CEILINGS WILL LIKELY HOLD UNTIL AROUND 18Z TOMORROW AFTERNOON.
SO...THE NEW TERMINALS HOLD MVFR CEILINGS UNTIL 18Z.
ALSO...A WEAK FRONTAL BOUNDARY HAS STALLED NEAR A SWEETWATER TO
ALBANY LINE. THIS SURFACE BOUNDARY MAY INITIATE SHOWERS AND
THUNDERSTORMS LATER THIS EVENING. HOWEVER...I DECIDED NOT TO
INCLUDE ANY THUNDER IN THE ABILENE TERMINAL BECAUSE MY CONFIDENCE
FOR WHEN AND WHERE THIS CONVECTION MAY INITIATE IS NOT VERY HIGH.
HUBER
PREV DISCUSSION... /ISSUED 340 PM CDT TUE APR 16 2013/
SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 68 86 56 62 36 / 10 20 40 10 5
SAN ANGELO 70 91 58 65 38 / 10 20 30 10 5
JUNCTION 70 89 63 70 39 / 5 20 50 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
957 AM EDT WED APR 17 2013
.UPDATE...
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT TO MODERATE
SHOWERS PUSHING SOUTHWEST ACROSS BISCAYNE BAY. LATEST HRRR AND
LOCAL SHORT RANGE MODELS KEEP THESE SHOWERS MAINLY ALONG AND SOUTH
OF U.S. HIGHWAY 41 THROUGH MUCH OF THE AFTERNOON. UPDATED POP AND
SKY GRIDS TO ACCOUNT FOR THIS. ALSO ADJUSTED TEMPERATURES
SLIGHTLY. UPDATE WILL BE SENT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 739 AM EDT WED APR 17 2013/
AVIATION...VFR WILL PREVAIL. A BRIEF SHOWER CANNOT BE RULED OUT
EAST COAST, BUT COVERAGE LOOKS SPARSE ENOUGH THROUGH THE PERIOD TO
PRECLUDE VCSH MENTION IN THE TAFS. HOWEVER, A GULF SEA BREEZE
DEVELOPING AT KAPF COULD ALLOW FOR A FEW SHOWERS, AND POSSIBLY A
TSTORM TO DEVELOP. FOR NOW INCLUDE VCSH THERE. WINDS WILL PREVAIL
OUT OF THE NE BECOMING EAST INCREASING TO 10-15KT THIS AFTERNOON,
EXCEPT THE SW GULF SEA BREEZE DEVELOPING AT KAPF MID AFTERNOON.
/GREGORIA
PREV DISCUSSION... /ISSUED 409 AM EDT WED APR 17 2013/
SHORT TERM (TODAY-FRIDAY)...
THE LATEST NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH THE SHORT-TERM PERIOD AND INDICATES THE UPPER RIDGE HOLDING
IN PLACE THROUGH TONIGHT...THEN GRADUALLY WEAKENING AND SHIFTING
EAST OVER THE WESTERN ATLANTIC AHEAD OF AN APPROACHING UPPER TROUGH
BY FRIDAY. AT THE SURFACE...THE LATEST IR LOOP AND ASCAT PASS SHOWED
A WEAK LOW CENTERED NNE OF THE BAHAMAS WITH A WEAK BOUNDARY
EXTENDING SW TOWARD SOUTH FLORIDA. THIS WEAK BOUNDARY COMBINED WITH
LIGHT EASTERLY LOW-LEVEL FLOW WILL KEEP A SLIGHT CHANCE OF MAINLY
LIGHT SHOWERS OVER THE ADJACENT ATLANTIC WATERS AND ALONG THE EAST
COAST AREAS THROUGH THE EARLY MORNING HOURS. SIMILAR TO
YESTERDAY...THE BEST CHANCE FOR AFTERNOON SHOWERS WILL REMAIN INLAND
TOWARD THE GULF COAST AS THE WEST COAST SEA BREEZE BEGINS TO
DEVELOP. THE LATEST MODEL SOUNDINGS OVER THESE INTERIOR AREAS ARE
SIMILAR TO YESTERDAY...HOWEVER...INDICATE DRIER AIR THROUGH THE
MID/UPPER LEVELS (PWAT VALUES AROUND 1.4") WITH THE BEST SOURCE OF
MOISTURE REMAINING WITHIN THE LOWER 5-10 KFT. AS A RESULT...
CONFIDENCE IN ANY DEEP MOIST CONVECTION OR THUNDERSTORM DEVELOPMENT
IS LOW. HOWEVER...A STORM OR TWO CAN NOT BE COMPLETELY RULED OUT
TODAY AS TEMPERATURES CLIMB BACK INTO THE LOWER 90S AND DEWPOINTS
REMAIN IN THE MID TO UPPER 60S. ON THURSDAY...THE LOW-LEVEL FLOW
WILL BEGIN TO SHIFT TOWARD THE SOUTHEAST...WHICH WILL TRANSLATE TO
THE BEST AFTERNOON SHOWER/TSTM CHANCES OVER THE NORTHWEST INTERIOR
OR FROM NAPLES TO THE LAKE REGION. ELSEWHERE...THE WARM CONDITIONS
WILL PERSIST WITH AFTERNOON HIGHS CLIMBING BACK INTO THE LOWER 80S
NEAR THE EAST COAST TO THE LOWER 90S INLAND. OVERNIGHT LOWS ARE
FORECAST TO RANGE FROM THE UPPER 60S INLAND TO THE LOW TO MID 70S
OVER THE EAST COAST AND METRO AREAS (SEVERAL DEGREES ABOVE THE
NORMAL LOWS) EACH NIGHT. ON FRIDAY...A COLD FRONT ASSOCIATED WITH
THE PREVIOUSLY MENTIONED UPPER TROUGH WILL BEGIN TO APPROACH THE
STATE. MOST OF THE SHOWERS/TSTM COVERAGE...HOWEVER...SHOULD REMAIN
NORTH OF OUR AREA THROUGH THE AFTERNOON PERIOD. PATCHY FOG WILL
REMAIN POSSIBLE EACH NIGHT...MAINLY OVER THE INTERIOR AREAS...WHICH
LINES UP WELL WITH THE LATEST SHORT-RANGE ENSEMBLE GUIDANCE.
LONG TERM (FRIDAY NIGHT-WEDNESDAY)...
THE EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT AND SHOWS THE
UPPER RIDGE CONTINUING TO SHIFT EAST OVER THE WESTERN ATLANTIC AS A
BROAD UPPER TROUGH SHIFTS EAST OVER THE REGION. A COLD FRONT
ASSOCIATED WITH THIS UPPER FEATURE IS FORECAST TO APPROACH AND BEGIN
TO IMPACT THE STATE OVER THE WEEKEND. INCREASING DEEP LAYER MOISTURE
COMBINED WITH THE APPROACHING FRONT/UPPER TROUGH WILL TRANSLATE TO
INCREASING RAINFALL CHANCES THROUGH THIS TIME. DEEP LAYER SOUTHWEST
FLOW WILL FAVOR ENHANCED ACTIVITY OVER THE EAST COAST
AREAS...ESPECIALLY FROM BROWARD COUNTY TO THE LAKE REGION. AS THE
FORECAST CONFIDENCE CONTINUES TO INCREASE THROUGH THE MID-WEEK
PERIOD...WE WILL BEGIN TO REFLECT THIS WITH INCREASING RAINFALL
CHANCES...ESPECIALLY FOR SATURDAY AND SUNDAY. CONFIDENCE BEYOND THIS
PERIOD INTO THE UPCOMING WEEK BEGINS TO DECREASE DUE TO SOME MODEL
DIFFERENCES. TEMPERATURES ARE FORECAST TO REMAIN AROUND OR SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS WILL BEGIN TO SHIFT TO THE
SOUTHEAST THURSDAY THROUGH FRIDAY AHEAD OF AN APPROACHING FRONTAL
BOUNDARY. THE COLD FRONT WILL LEAD TO INCREASING RAINFALL CHANCES
FRIDAY THROUGH THE UPCOMING WEEKEND AS THE BOUNDARY STALLS NEAR OR
OVER THE AREA. WINDS WILL SHIFT BACK TO THE EAST LATER IN THE
WEEKEND AND INTO THE UPCOMING WEEK AS THE FRONT WEAKENS AND HIGH
PRESSURE BUILDS BACK OVER THE REGION.
FIRE WEATHER...
PLENTY OF MOISTURE WITH DEWPOINTS REMAINING IN THE MID 60S WILL
KEEP RELATIVE HUMIDITIES WELL ABOVE CRITICAL LEVELS THROUGH THE
AFTERNOON PERIODS. LOW-LEVEL FLOW WILL REMAIN OUT OF THE EAST AND
SOUTHEAST WITH THE BEST CHANCE FOR AFTERNOON SHOWERS AND POSSIBLY
A STORM OR TWO REMAINING OVER THE INTERIOR LOCATIONS TOWARD THE
GULF COAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 83 74 / 10 - 10 10
FORT LAUDERDALE 82 76 84 77 / 10 - 10 20
MIAMI 84 73 85 75 / 20 - 10 10
NAPLES 88 69 88 70 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1124 AM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS THROUGH
THURSDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1120 AM WEDNESDAY...
TODAY: FORECAST CHALLENGE REMAINS THE THREAT OF SHOWERS/STORMS. A
MESO-CONVECTIVE VORTEX NEAR KMTV...PER RADAR AND VISIBLE IMAGERY
THIS MORNING...IS FORECAST BY THE THE RAP/RUC TO DRIFT SLOWLY IN WNW
FLOW ALOFT ACROSS THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN
THROUGH 00Z. SHOWERS IN THE DEFORMATION ZONE TO THE NORTH OF THE
VORT CENTER ARE ALL THAT REMAIN...AND THESE WILL AFFECT AREAS
ADJACENT TO THE VA BORDER DURING THE NEXT SEVERAL HOURS. IN ADVANCE
OF THESE SHOWERS AND ASSOCIATED MID LEVEL CEILINGS - GENERALLY
ACROSS ALL BUT THE NW PIEDMONT - THE AIR MASS WILL DESTABILIZE WITH
STRONG INSOLATION AS TEMPERATURES RISE INTO THE LOWER TO MIDDLE
80S...AND BECOME PRIMED FOR SCATTERED STORM DEVELOPMENT WITH THE
APPROACH OF THE MCV. CORFIDI VECTORS INDICATE THE UPSTREAM MCS
MOVING INTO THE NORTHERN NC MOUNTAINS WILL ONLY GRAZE THE FAR
WESTERN AND SOUTHERN PIEDMONT AND/OR WEAKEN. GIVEN VERY WEAK
WINDS ALOFT... PRIMARILY ONLY A DISORGANIZED/PULSE SUB-SEVERE
CONVECTIVE MODE IS EXPECTED. HOWEVER...IF STORMS DEVELOP IN AN ARC
IN ADVANCE OF THE MCV AS THE HRRR SUGGESTS...MULTI-CELL MERGING OF
THE ASSOCIATED COLD POOLS...AND RELATIVELY STEEP LOW LEVEL LAPSE
RATES (AROUND 8 C/KM)...WOULD PROMOTE A MARGINALLY SEVERE WIND
THREAT.
AS OF 300 AM WEDNESDAY...
TONIGHT: ANY ONGOING CONVECTION SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING WITH AREAS OF FOG AND OR STRATUS POSSIBLE. LOWS IN
THE MIDDLE TO UPPER 50S
THURSDAY AND THURSDAY NIGHT:
AS THE UPPER TROUGH PROGRESSES SLOWLY EASTWARD INTO THE PLAINS AND
UPPER MIDWEST ON THURSDAY...RIDGE ALOFT WILL SHIFT EAST AND
OFFSHORE. A NICE 15 TO 20 KT OF ONSHORE FLOW DEVELOPS WITH ANY
CONVECTION LARGELY REMAINING ALONG THE UPSLOPE REGIME IN THE
FOOTHILLS AND MOUNTAINS WITH THE RE-EMERGENCE OF A STRONG MID-LEVEL
CAP OVER THE AREA KEEPING IT DRY. HIGHS IN THE UPPER 70S TO LOWER
80S. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THE APPROACHING COLD
FRONT WILL KEEP LOWS THURSDAY NIGHT IN THE LOWER 60S WITH AREAS OF
LOW CLOUDS/STRATUS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM WEDNESDAY...
A DEAMPLIFYING UPPER TROUGH WILL CONTINUE TO PUSH EAST THROUGHOUT
THE DAY ON FRIDAY...PROPELLING A TRAILING COLD FRONT THROUGH THE
REGION FRIDAY/FRIDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY
THIS SYSTEM AS IT MOVES ACROSS CENTRAL NC AND THE MAIN CONCERN
CONTINUES TO BE THE POTENTIAL FOR SEVERE WEATHER. MODELS ARE IN
DECENT AGREEMENT WITH THE LINE OF SHOWERS AND THUNDERSTORMS MOVING
ACROSS CENTRAL NC FROM WEST TO EAST LATE FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS IS COMMONLY THE CASE...PLENTY OF SHEAR
WILL BE IN PLACE...BUT THE AMOUNT OF INSTABILITY WILL BE THE MAIN
LIMITING FACTOR. MODELS CONTINUE TO PROG ONLY WEAK/MARGINAL
INSTABILITY...LIKELY DUE TO THE EXTENSIVE CLOUD COVER EXPECTED AHEAD
OF THE APPROACHING FRONT...AS WELL AS THE MOSTLY NOCTURNAL TIMING OF
THE PRECIP (THIS SECOND POINT WILL MOSTLY COME INTO PLAY ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA). THIS WILL CONTINUE TO BE
MONITORED...AS TIMING STILL COULD CHANGE. NEVERTHELESS...WILL
CONTINUE TO MENTION THE POSSIBILITY OF STRONG TO SEVERE
STORMS...WITH THE PRIMARY THREAT BEING DAMAGING WIND...IN THE HWO.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE UPPER 70S ACROSS THE
WEST TO LOW/MID 80S FURTHER EAST. OVERNIGHT LOWS ON FRIDAY NIGHT
WILL BE DEPENDENT ON THE TIMING OF THE EXITING PRECIP AND
COMMENCEMENT OF COLD AIR ADVECTION. AT THIS TIME...IT APPEARS PRECIP
SHOULD CLEAR OUT OF AT LEAST THE WESTERN PORTIONS OF THE FORECAST
AREA BEFORE DAYBREAK AND THEREFORE AM EXPECTING TEMPS TO RANGE FROM
THE UPPER 40S/LOWER 50S ACROSS THE WEST TO MID/UPPER 60S FURTHER
EAST. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY ON SATURDAY AND
WITH COLD AIR ADVECTION PERSISTING...HIGHS SHOULD GENERALLY BE IN
THE MID/UPPER 60S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
BEHIND THE DEPARTING FRONT...HIGH PRESSURE WILL BUILD INTO THE
REGION...RESULTING IN COOLER AND DRIER WEATHER FOR THE WEEKEND.
THEN...THERE CONTINUES TO BE SOME UNCERTAINTY WITH RESPECT TO PRECIP
EARLY NEXT WEEK. THE FRONT IS PROGGED TO STALL NOT TOO FAR OFFSHORE
AND MODELS PROG A WAVE/INVERTED TROUGH THAT DEVELOPING ALONG IT
EARLY NEXT WEEK. BOTH THE GFS AND ECMWF INDICATE THIS SCENARIO
OCCURRING...BUT DIFFER ON THE TIMING OF SPREADING ANY PRECIP BACK
TOWARDS THE REGION. FOR NOW WILL MAINTAIN SLIGHT CHANCE
POPS...MAINLY CENTERED ACROSS THE EAST...BOTH MONDAY AND TUESDAY
(ALTHOUGH CONFIDENCE IS FAIRLY LOW). REGARDLESS...AS HIGH PRESSURE
RIDGES DOWN THE EASTERN SLOPES OF THE MOUNTAINS AND AN INVERTED
TROUGH DEVELOPS ACROSS THE WESTERN ATLANTIC...COOL AND MOIST
NORTHEASTERLY FLOW WILL PERSIST ACROSS CENTRAL NC. THIS WILL LEAD TO
A STRETCH OF BELOW NORMAL TEMPS...WITH HIGHS GENERALLY IN THE 60S
AND OVERNIGHT LOWS IN THE 40S EXPECTED THROUGH EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM WEDNESDAY...
ANY PATCHY FOG WILL QUICKLY LIFT AND DISSIPATE SHORTLY AFTER 12Z
WITH PREDOMINATELY VFR CONDITIONS INTO THE AFTERNOON BEFORE SCATTERED
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL BRING THE
THREAT FOR LOCALIZED SUB-VFR CONDITIONS IN HEAVY RAIN. CONVECTION
WILL DIMINISH AFTER SUNSET WITH AREAS OF FOG/STRATUS POSSIBLE
THURSDAY MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAIN.
LOOKING AHEAD: MORNING FOG/STRATUS WILL POSE A THREAT AGAIN FRIDAY
MORNING. OTHERWISE EXPECT VFR CONDITIONS UNTIL THE ARRIVAL OF A COLD
FRONT AND PRECEDING SHOWERS AND STORMS FRI-FRI NIGHT. VFR CONDITIONS
IN ASSOCIATED WITH SURFACE HIGH PRESSURE RETURN FOR THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
638 AM EDT WED APR 17 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN STALLED ACROSS THE REGION
TODAY...LIFTING NORTH OF THE REGION AS A WARM FRONT BY TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. WARM SOUTHERLY FLOW WILL
EXIST OVER THE REGION ON THURSDAY...BEFORE A STRONG COLD FRONT
BRINGS SHOWERS AND STORMS (AND MUCH COLDER TEMPERATURES) EARLY
FRIDAY MORNING. COOLER CONDITIONS ARE EXPECTED FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THUNDER CONTINUES TO RUMBLE ACROSS THE REGION EARLY THIS
MORNING...PARTICULARLY ACROSS THE IND AND ILN FORECAST AREAS.
CONVECTION IS REPEATEDLY DEVELOPING ON THE COOL SIDE OF THE
SURFACE BOUNDARY...AIDED BY QUITE A BIT OF CONVERGENCE AND
MOISTURE TRANSPORT JUST OFF THE SURFACE. THIS FORCING WAS TOUGH TO
PICK OUT...AS IT APPEARS TO BE WITHIN A LAYER OF SOUTHWESTERLY
FLOW FROM JUST OFF THE SURFACE TO AROUND 875MB. WINDS AT 850MB
AND ABOVE ARE MORE WESTERLY THAN SOUTHWESTERLY.
ALL SIGNS (QPF OUTPUT...HIGH-RES SIMULATED REFLECTIVITY...AND A
WEAKENING TO THE SOUTHWESTERLY FLOW) POINT TOWARD A GRADUAL
WEAKENING TREND LATER IN MORNING HOURS. HOWEVER...THE ACTIVITY IS
EXPECTED TO PERSIST FOR THE NEXT SEVERAL HOURS AT LEAST...AND THE
RECENT HRRR RUNS ARE FINALLY PICKING UP ON THIS A BIT (THOUGH THEY
SEEM TO MOVE THE CONVECTION ON TOO SOUTHERLY A TRAJECTORY). POPS
ARE VERY HIGH (AS HIGH AS 100 PERCENT) DURING THE EARLY
MORNING...BEFORE DIMINISHING SIGNIFICANTLY BY LATE MORNING AND
AFTERNOON.
THE FRONTAL BOUNDARY WILL BEGIN TO LIFT NORTH LATER TODAY...BUT IT
IS NOT AS WELL DEFINED AS IT WAS YESTERDAY. SUPPORT FOR FORCING IS
ALSO NOT ESPECIALLY STRONG...AS 500MB HEIGHTS RISE.
THEREFORE...CONVECTION IS NOT EXPECTED TO BE AS WIDESPREAD AS IT
WAS ON TUESDAY...NOR WILL IT BE LIKELY TO BE AS STRONG. THERE
SHOULD BE ENOUGH INSTABILITY ALONG AND SOUTH OF THE BOUNDARY TO
SUPPORT A LOW-END SEVERE THREAT...BUT SHEAR IS NOT IMPRESSIVE
(20-30 KNOTS 0-6KM...PERHAPS EVEN LESS IN THE FAR SOUTH).
TEMPERATURE LEVELS WILL ALSO BE RISING A BIT FROM WHERE THEY ARE
AT NOW (AND WHERE THEY WERE LAST EVENING). SO...THE HWO WILL
INCLUDE A HEDGED MENTION...AS SEVERE WEATHER LOOKS UNLIKELY BUT
NOT TOTALLY IMPOSSIBLE.
TEMPS WERE NOT EASY TODAY...GIVEN THE ABUNDANCE OF CLOUDS AND THE
TOUGH FORECAST FOR THE LOCATION OF THE BOUNDARY. TEMPS WERE KEPT
CLOSE TO GUIDANCE...THOUGH COOLER THAN THE RAW NAM12. THE GRADIENT
ACROSS THE CWA IS TIGHT...WITH UPPER 70S IN THE FAR SOUTH AND MID
60S IN THE FAR NORTH. DEPENDING ON HOW SLOW THE MORNING CONVECTION
DISSIPATES...THERE COULD BE BUST POTENTIAL WITH THESE NUMBERS
BEING TOO HIGH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
THE FRONTAL BOUNDARY WILL BE NORTH OF THE REGION BY WEDNESDAY
NIGHT...WITH THE CWA UNDER A MID-LEVEL RIDGE AND ENTERING A REGIME
OF SOUTHERLY FLOW. THIS SHOULD LOCK MOST OF THE CWA (ALL BUT THE
NORTHWEST CORNER) IN THE WARM SECTOR...HELPING TO SIGNIFICANTLY
DIMINISH CHANCES OF PRECIPITATION THROUGH THE DAY ON THURSDAY.
WHILE SOME DIURNAL CONVECTION MAY BE POSSIBLE AT THE NORTH AND
WEST FRINGES OF THE CWA ON THURSDAY AFTERNOON...A LACK OF FORCING
AND PERHAPS SOME CAPPING WILL LIMIT THIS POTENTIAL. THE
SOUTHEASTERN HALF OF THE CWA SHOULD ALMOST CERTAINLY REMAIN DRY.
AS THE SOUTHWESTERLY FLOW INCREASES...AND CONDITIONS MIX RATHER
WELL ON THURSDAY...WIND GUSTS INTO THE 30-40 MPH RANGE APPEAR
POSSIBLE. IN FACT...BOTH THE GFS/NAM ARE SHOWING GUSTS AS HIGH AS
45 MPH ON BUFKIT IN THE FAR NORTH (NEAR LIMA OH). WITH THE STRONG
WARM ADVECTION...THE MAX TEMP FORECAST FOR THURSDAY REMAINS WELL
ABOVE NORMAL...WITH MID 80S IN THE SOUTHEAST PART OF THE CWA.
MODELS APPEAR TO BE IN VERY GOOD AGREEMENT ON THE BIG CONCLUSION
TO THE UNSETTLED WEATHER THIS WEEK. LOW PRESSURE IS FORECAST TO
MOVE NORTHEAST TOWARD CHICAGO BY THURSDAY NIGHT...AND THEN ONWARD
TO THE STRAITS OF MACKINAC BY FRIDAY MORNING. A STRONG COLD FRONT
WILL MOVE EASTWARD THROUGH THE MISSISSIPPI VALLEY THURSDAY
EVENING...AND THEN THROUGH THE OHIO VALLEY INTO THE ILN CWA BY
EARLY FRIDAY MORNING.
SPC HAS PLACED A LARGE AREA INTO A HIGH-END SLIGHT
RISK ON DAY2. THIS RISK AREA IS GENERALLY ALONG AND AHEAD OF THE
EXPECTED POSITION OF THE COLD FRONT...AS IT PROGRESSES FROM THE
AFTERNOON INTO THE EARLY OVERNIGHT HOURS ON THURSDAY. THERE IS NO
QUESTION THAT THE BEST SEVERE POTENTIAL IS WEST OF THE ILN
CWA...WHERE DIURNAL INSTABILITY WILL BE GREATEST. HOWEVER...SHEAR
WILL CONTINUE TO BE VERY STRONG EVEN THROUGH THE OVERNIGHT HOURS
AND INTO FRIDAY MORNING. FLOW AT ALL LEVELS WILL INCREASE AHEAD OF
THE FRONT...WITH A LOW-LEVEL JET OF 60-70 KNOTS AT 850MB NEAR 06Z.
INSTABILITY WILL BE THE POTENTIAL LIMITING FACTOR FOR SEVERE
WEATHER...GIVEN UNFAVORABLE NEAR-SURFACE THERMODYNAMIC PROFILES AT
THE TIME THE WEAKENING FRONTAL CONVECTION IS MOVING INTO THE CWA.
AT THEIR MOST FAVORABLE...SOME OF THE MODEL SOUNDINGS ARE ROUGHLY
MOIST-ADIABATIC...WHILE OTHERS DISPLAY MORE OF A SLIGHTLY-INVERTED
PROFILE.
THIS SCENARIO WILL BE CLOSELY MONITORED OVER THE NEXT FEW
DAYS...AS THE STRONG WIND FIELDS MEAN THAT SEVERE WEATHER COULD BE
POSSIBLE EVEN WITH THE UNFAVORABLE TIMING. EVEN ASIDE FROM THE
CONVECTIVE POTENTIAL...BUFKIT SOUNDINGS ARE INDICATING WIND GUSTS
OF 25-30 KNOTS BEHIND THE FRONT. THE PROGRESSIVE NATURE OF THE
FRONT WILL LIKELY LIMIT ANY POTENTIAL FLOODING ISSUES...BUT THE
MOISTURE TRANSPORT APPEARS TO BE VERY STRONG...AND RAINFALL
AMOUNTS OF OVER AN INCH WILL BE POSSIBLE (ESPECIALLY IN THE
WESTERN HALF OF THE CWA).
NON-DIURNAL TEMPS WERE DRAWN IN FOR FRIDAY...WITH MAX TEMPS
EXPECTED IN THE MORNING...AND A SIGNIFICANT DECREASE BEHIND THE
FRONT. AS AN EXAMPLE OF THE EXPECTED CHANGE IN AIR MASS...NAM12
850MB TEMPS AT KILN ARE FORECAST TO GO FROM +14C AT 06Z FRIDAY
MORNING TO -5C JUST 24 HOURS LATER.
BEHIND THE FRONT...LOW LEVEL MOISTURE IS EXPECTED TO BE VERY SLOW
TO SCOUR OUT. SOME TROUGHING ALOFT WILL BRING A SLIGHT CHANCE OF
SHOWERS TO THE NORTHERN CWA ON FRIDAY AFTERNOON...BUT A LACK OF
DEEPER MOISTURE IS LIMITING QPF AMOUNTS TO JUST A FEW HUNDREDTHS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRESSURE AND DRY AIR WILL BUILD IN FOR SATURDAY THROUGH MONDAY.
ANOTHER STRONG COLD FRONT WILL APPROACH FROM THE WEST ON TUESDAY
BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
AFTER A MORNING HIGH NEAR 60 ON FRIDAY...HIGHS WILL BE MAINLY IN THE
50S SATURDAY AND SUNDAY. A REBOUND BACK INTO THE 60S IS INDICATED
FOR MONDAY AND TUESDAY AS WARM ADVECTION OCCURS IN THE RETURN FLOW
OF HIGH PRESSURE. TO COINCIDE WITH THE START OF OUR FROST/FREEZE
PROGRAM FOR THE ENTIRE ILN AREA...FROST WILL BE POSSIBLE SUNDAY
MORNING WHEN TEMPERATURES ARE FORECAST TO FALL TO THE LOWER TO
MIDDLE 30S.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A NEARLY STATIONARY FRONT NEAR THE OHIO RIVER THIS MORNING WILL
MOVE SLOWLY BACK NORTH AS A WARM FRONT TODAY...AND WILL LIFT INTO
THE SOUTHERN GREAT LAKES TONIGHT.
SCATTERED SHOWERS AND A FEW RUMBLES OF THUNDER THIS MORNING SHOULD
DWINDLE IN COVERAGE AS A WEAK LOW LEVEL JET/CONVERGENCE AXIS
NORTH OF THE STATIONARY BOUNDARY EVENTUALLY WEAKEN BY MID DAY.
THEREAFTER...PROSPECTS OF CONTINUE CONVECTION APPEAR LOW AT THIS
TIME AND WILL DEPEND ON HOW MUCH SURFACE BASED INSTABILITY CAN BE
REALIZED NEAR THE FRONT. DO NOT HAVE CONFIDENCE TO PLACE IN THE
TAFS AT THIS TIME SO HAVE LEFT OUT.
THE OTHER CONCERN THIS MORNING INTO THE EARLY AFTERNOON HOURS WILL
BE THE AMPLE LOW LEVEL MOISTURE THAT IS IN PLACE FROM THE RECENT
RAINS. THIS WILL LIKELY YIELD IFR CIGS AND MVFR VSBYS EARLY ON.
DAYTIME HEATING SHOULD ALLOW BOTH TO IMPROVE TO VFR DURING THE
AFTERNOON HOURS.
FOR TONIGHT...LARGE SCALE MID LVL TROUGH WILL PUSH EAST INTO THE
PLAINS. THIS WILL ALLOW THE MID LVL FLOW TO BUCKLE AS WARM FRONT
ADVANCES NORTH INTO THE SOUTHERN GREAT LAKES. SOME MODELS SUGGEST
THAT SOME CONVECTION COULD GRAZE OUR WESTERN FORECAST AREA EARLY
ON..BUT CONFIDENCE IN THIS IS LOW ATTM SO HAVE MAINTAINED A DRY
FORECAST. OTHERWISE...VFR CONDITIONS ARE EXPECTED OVERNIGHT.
OUTLOOK...GUSTY SOUTH/SOUTHWEST WINDS OF 30 TO 35 KNOTS LIKELY ON
THURSDAY. SHOWERS AND THUNDERSTORMS THURSDAY NIGHT INTO FRIDAY.
GUSTY WEST WINDS TO 30 KNOTS LIKELY BEHIND FRONTAL PASSAGE ON
FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
632 AM CDT WED APR 17 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
ACTIVE TAF PERIOD WITH TSRA CHANCES INCREASING AT ALL TAF SITES...
ESPECIALLY AFTER 00Z. MVFR CIGS EXPECTED THROUGH 16-18Z...WITH
A BRIEF WINDOW FOR VFR CONDITIONS THROUGH LATE AFTERNOON. CIGS TO
LOWER TO MVFR CATEGORIES FROM LATE AFTERNOON THROUGH THE REST OF
THE TAF PERIOD. TSRA WILL START TO BECOMING MORE WIDESPREAD...AND
AFFECTING THE OK TAF SITES AFTER SUNSET. WINDS WILL SHIFT TO THE
NORTHWEST WITH FROPA AROUND 09Z. MVFR CIGS AND RAIN TO CONTINUE
BEHIND THE FRONT.
&&
.PREV DISCUSSION... /ISSUED 422 AM CDT WED APR 17 2013/
DISCUSSION...
FRONTAL BOUNDARY HAS BEGUN TO SLOWLY LIFT NORTH AS A WARM FRONT
AND THE NORTHWARD PROGRESS OF THIS FRONT SHOULD ACCELERATE OVER
THE NEXT FEW HOURS WITH THE ENTIRE FORECAST AREA IN THE WARM
SECTOR BY LATER THIS MORNING. CONVECTIVE EVOLUTION TODAY IS
UNCLEAR WITH A MYRIAD OF SOLUTIONS DEPICTED BY THE VARIOUS MODELS.
LARGE SCALE HEIGHT FALLS WILL BEGIN THIS MORNING AHEAD OF THE
UPPER SYSTEM CURRENTLY IN UTAH AND THIS SHOULD RESULT IN A
WEAKENING OF THE CAP. SEVERAL MODELS INCLUDING THE HRRR DEPICT A
GRADUAL UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY THIS
MORNING...MAINLY ACROSS NORTHEAST OKLAHOMA. WILL CARRY THE HIGHEST
POPS IN THIS AREA TODAY WITH MUCH LOWER POPS TO THE SOUTH. ANY
STORMS THAT REMAIN DISCRETE TODAY WILL CARRY A HIGH SEVERE
POTENTIAL.
CONVECTIVE COVERAGE WILL INCREASE OVERNIGHT AS THE UPPER SYSTEM
AND ASSOCIATED COLD FRONT APPROACH THE AREA. A SQUALL LINE WILL
EVENTUALLY DEVELOP ALONG THE COLD FRONT AND SWEEP ACROSS THE AREA
OVERNIGHT. SHOWERS AND STORMS WILL LINGER BEHIND THE FRONT BUT THE
LATEST DATA SUPPORT A QUICKER EXIT TO THE RAIN THURSDAY. THIS
SHOULD ALLOW FOR SOME TEMPERATURE RECOVERY THURSDAY AFTERNOON.
TOTAL RAINFALL AMOUNTS FROM THIS SYSTEM MAY BE NEAR 3 INCHES IN
SOME PLACES...MAINLY IN THE NORTH...SO WILL HAVE TO WATCH THE
FLOODING POTENTIAL ESPECIALLY OVERNIGHT INTO THURSDAY MORNING.
TEMPERATURES WILL DROP TO NEAR OR BELOW FREEZING IN MANY PLACES
THURSDAY NIGHT WITH SOME PLACES LIKELY SEEING THEIR COLDEST
READINGS RECORDED FOR SO LATE IN THE SEASON. APRIL 15TH IS THE
LATESE FREEZE ON RECORD IN MCALESTER AND TULSA HAS NEVER BEEN
COLDER THAN 32 AFTER APRIL 18TH DURING THE PERIOD OF RECORD. A
WARMING TREND WILL TAKE PLACE OVER THE WEEKEND BUT ANOTHER STRONG
COLD FRONT IS SET TO MOVE THROUGH THE AREA EARLY NEXT WEEK. THE
LATEST DATA SUPPORTS A SLOWER FRONTAL PASSAGE SO THE HIGHEST RAIN
CHANCES WILL BE MONDAY NIGHT AND TUESDAY. TEMPERATURES BEHIND THIS
FRONT MAY ONCE AGAIN FLIRT WITH THE FREEZING MARK IN SOME PLACES
BY NEXT WEDNESDAY MORNING.
MADE SOME SIGNIFICANT ADJUSTMENTS TO GUIDANCE TEMPERATURES AGAIN
FOR TONIGHT AND THURSDAY BASED ON THE FORECAST FRONTAL MOVEMENT
AND THE VERIFICATION CUTOFF TIMES...WITH THE SIMILAR ECMWF AND NAM
FOLLOWED ON FRONTAL TIMING.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...23
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1058 AM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS EXPECTED TO
CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND REMAIN
IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 EDT...CONVECTIVE CLUSTER OVER NE TN/SE KY HAS ENTERED NW
CAROLINA AND CONTINUES TO MOVE SE. LATEST HRRR CONTINUES TO LATCH
ONTO TO THIS CONVECTION AND MOVE/DEVELOP NUMEROUS CONVECTIVE CELLS
ACROSS THE NC MOUNTAINS IN THE EARLY TO MID AFTENROON HOURS...AND
THEN INTO THE PIEDMONT MID TO LATE AFTERNOON. MADE SOME ADJUSTMENTS
TO POP GRID TO INCREASE COVERAGE AND TWEAK TIMING.
PREVIOUS DISCUSSION:
AS OF 915AM...CURRENT REGIONAL RADARS SHOW A CLUSTER OF
SHOWERS/STORMS OVER NE TN/SW VA AND SE KY MOVING SE. THIS MOVEMENT
WILL BRING AT LEAST SCT SHOWERS/THUNDERSTORMS INTO THE NORTHERN
MOUNTAINS THIS MORNING. THE LATEST HRRR SHOWS NUMEROUS
SHOWERS/THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS AROUND MIDDAY
APPARENTLY ACTIONG ON THE OUTFLOW BOUNDARY FROM THE EARLY MORNING
CONVECTION. THE HRRR THEN MOVES THE CONVECTION INTO THE PIEDMONT BY
LATE AFTERNOON. THE 06Z NAM SUPPORTS THIS GENERAL IDEA AS WELL.
HENCE...HAVE UPPED POPS INTO THE NUMEROUS RANGE FOR MOST OF THE
MOUNTAINS TODAY WITH SCATTERED COVERAGE OVER THE PIEDMONT
AREAS...EXCEPT ISOLD THE SOUTHERN UPSTATE. ALSO UPDATED
TEMP/DEWPOINT/WIND TRENDS FOR THE MORNING.
CANNOT RULE OUT ISOLATED SVR STORMS...MAINLY ACROSS THE MTNS...WITH
LOW WET BULB ZERO LEVELS AND SOME DCAPE DEVELOPING. HIGHS LOOK TO BE
A TAD COOLER THAN PREV FCST...BUT STILL ABOUT 10 DEGREES ABOVE
NORMAL.
CONVECTION WILL LINGER INTO THE EARLY EVENING...BUT DISSIPATE DURING
THE LATE EVENING WITH LOSS OF HEATING. LOW LEVEL SELY FLOW DEVELOPS
OVERNIGHT. WITH CONTINUED COPIOUS LOW LEVEL MOISTURE...EXPECT
ISOLATED SHOWERS TO LINGER ALONG THE BLUE RIDGE EVEN AFTER MIDNIGHT.
THIS WILL ALSO LEAD TO CONTINUED CLOUDINESS. LOWS SHUD BE 10 TO 15
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AT 230 AM EST WEDNESDAY...AN UPPER RIDGE WIL BE OFF THE EAST COAST
ON THURSDAY...WITH A TROUGH OVER THE PLAINS. BY FRIDAY MORNING...
THE TROUGH WILL BE OVER THE MS RIVER VALLEY. ON FRIDAY NIGHT THE
TROUGH WILL START TO DEAMPLIFY OVER THE CENTRAL AND SOUTHERN
APPALACHIANS.
A MOIST SOUTHEASTERLY FLOW WILL BE OVER GA AND THE CAROLINAS ON
THURSDAY IN ADVANCE OF A COLD FRONT MOVING INTO THE MS RIVER VALLEY.
THE MODELS SHOW RATHER LIMITED INSTABILITY DURING THE DAY...MAINLY
OVER THE MOUNTAINS AND THE PIEDMONT. AS THE FRONT CROSSES THE TN
RIVER VALLEY FRIDAY NIGHT...MOIST INFLOW INCREASES WITH A TIGHTENING
PRESSURE GRADIENT...SUPPORTING INCREASING POPS. INSTABILITY WILL
WANE IN THE EVENING..THEN INCREASE TOWARD DAYBREAK IN THE
MOUNTAINS...COINCIDING WITH MODERATE SHEAR. BY MIDDAY FRIDAY THE
FRONT WILL BE ALONG THE INTERSTATE 85 CORRIDOR...BY WHICH TIME THE
MODEL SHOW THE BEST INSTABILITY OUT AHEAD OF THE BEST HELICITY...
ALTHOUGH ENOUGH OVERLAP IS PRESENT TO BE OF CONCERN. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT UNTIL FRIDAY...WHEN CLOUDS
AND PRECIPITATION WILL HOLD MAXIMUMS TO AROUND NORMAL.
THE FRONT WILL MOVE EAST OF OUR AREA SATURDAY EVENING...WITH A DRIER
AND COOLER AIR MASS MOVING IN FROM THE WEST OVERNIGHT. ALTHOUGH
MINIMUM TEMPERATURES WILL BE IN THE MID 30S AT HIGHER ELEVATIONS OF
THE NC MOUNTAINS... THE DRIER AIR COMBINED WITH POST FRONTAL WINDS
SHOULD PREVENT FROST FROM FORMING.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AT 230 AM EST WEDNESDAY...THE EASTERN TROUGH WILL CONTINUE TO
DEAMPLIFY OVER THE WEEKEND...WHILE ANOTHER TROUGH SLOWLY AMPLIFIES
OVER THE PLAINS. THE RESULT WILL BE A NEARLY ZONAL FLOW OVER THE
EASTERN TWO THIRDS OF THE NATION. BY MONDAY THE PATTERN AMPLIFIES...
WITH AN EAST COAST RIDGE AND CENTRAL USA TROUGH. ON TUESDAY THE
TROUGH MOVES OFF THE EAST COAST...AND THE RIDGE UPSTREAM REACHES THE
MS RIVER VALLEY.
SATURDAY AND SUNDAY FEATURE DRY HIGH PRESSURE MOVING ACROSS THE
APPALACHIANS. BY MONDAY THIS SURFACE HIGH WILL EXTEND ALONG THE
EASTERN SEABOARD...WHILE THE OLD SURFACE FRONT WILL BE STALED NEAR
THE GULF COAST. ISENTROPIC UPGLIDE OVER THIS BOUNDARY WILL SPREAD
CLOUDS AND PRECIPITATION NORTH ACROSS OUR AREA. THE SURFACE RIDGE
WEAKENS ON TUESDAY...WHILE ANOTHER COLD FRONT WILL MOVE INTO THE TN
RIVER VALLEY FORM THE WEST. MAXIMUM TEMPERATURES WILL RUN AROUND SIX
OR SEVEN DEGREES BELOW NORMAL FROM SATURDAY THROUGH TUESDAY....WHILE
MINIMUM TEMPERATURES RUN AROUND NORMAL.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP. HOWEVER...EXPECT SCT
LOW VFR WITH BKN HIGHER CLOUDS THIS MORNING AS CONVECTIVE DEBRIS
FROM THE DYING CONVECTION TO THE NW MOVES OVERHEAD. DO NOT EXPECT
THIS CONVECTION TO AFFECT THE AIRFIELD...CANNOT RULE OUT SOME
SPRINKLES THIS MORNING. OTHERWISE...LOW VFR SHUD DEVELOP DURING THE
AFTERNOON. GUIDANCE STILL SUGGESTS BETTER CHC OF CONVECTION OVER THE
PIEDMONT THIS AFTERNOON. THEREFORE...HAVE INCLUDED A PROB30 FOR LATE
AFTERNOON/EARLY EVENING. CONVECTION SHUD DIE OFF DURING THE
EVENING...BUT LOW VFR CONTINUES OVERNIGHT. HAVE KEPT IT AT VFR FOR
NOW EVEN THO SOME GUIDANCE SUGGESTING LOWER CIGS. SWLY WINDS BECOME
SLY THRU THE DAY AND SELY OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP
BUT NEITHER DID FOG. HAVE INCLUDED EARLY PRECIP AT KAVL/KHKY TO
ACCOUNT FOR THE CURRENT CONVECTION. HOWEVER...DO NOT EXPECT ANY
RESTRICTIONS...BUT WOULD BE BRIEF IF THEY DID DEVELOP. STILL EXPECT
BETTER CHC OF CONVECTION AT KHKY/KAVL WITH ONLY SLIGHT CHC OVER THE
SC SITES. KEPT THE PROB30 GOING FOR KHKY/KAVL. CONVECTION SHUD
DIMINISH DURING THE EVENING...BUT LOW LEVEL SELY FLOW COULD KEEP
ISOLATED SHRA GOING ALONG THE BLUE RIDGE. DO NOT EXPECT ANY
RESTRICTIONS EXCEPT NEAR CONVECTION UNTIL OVERNIGHT NEAR THE BLUE
RIDGE WITH THE MOIST SELY FLOW. THEREFORE...DID BRING MVFR TO KAVL
BY MORNING. GENERALLY SWLY FLOW BECOMES SLY THEN SELY THRU THE
PERIOD.
OUTLOOK...SOUTHERLY FLOW WILL INCREASE ACROSS THE AREA ON THU. A
COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH THUNDERSTORMS AND
ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES WILL RETURN OVER THE
WEEKEND.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 100% HIGH 100% HIGH 98% HIGH 90%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KAVL HIGH 100% HIGH 100% HIGH 98% HIGH 87%
KHKY HIGH 100% HIGH 100% HIGH 98% MED 72%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 80%
KAND HIGH 100% HIGH 100% HIGH 98% HIGH 90%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
919 AM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS EXPECTED TO
CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND REMAIN
IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 915AM...CURRENT REGIONAL RADARS SHOW A CLUSTER OF SHOWERS/STORMS
OVER NE TN/SW VA AND SE KY MOVING SE. THIS MOVEMENT WILL BRING AT
LEAST SCT SHOWERS/THUNDERSTORMS INTO THE NORTHERN MOUNTAINS THIS
MORNING. THE LATEST HRRR SHOWS NUMEROUS SHOWERS/THUNDERSTORMS
DEVELOPING OVER THE MOUNTAINS AROUND MIDDAY APPARENTLY ACTING ON
THE OUTFLOW BOUNDARY FROM THE EARLY MORNING CONVECTION. THE HRRR
THEN MOVES THE CONVECTION INTO THE PIEDMONT BY LATE AFTERNOON. THE
06Z NAM SUPPORTS THIS GENERAL IDEA AS WELL. HENCE...HAVE UPPED
POPS INTO THE NUMEROUS RANGE FOR MOST OF THE MOUNTAINS TODAY WITH
SCATTERED COVERAGE OVER THE PIEDMONT AREAS...EXCEPT ISOLD THE
SOUTHERN UPSTATE. ALSO UPDATED TEMP/DEWPOINT/WIND TRENDS FOR THE
MORNING.
PREVIOUS DISCUSSION:
AS OF 7 AM...LINE OF CONVECTION MOVED INTO THE NC MTNS AND BECAME AN
AREA OF SHRA. EXPECT THE SHRA TO MOVE ACROSS THE NRN TIER...AND
POSSIBLY INTO THE SRN NC FOOTHILLS AND PIEDMONT BEFORE DISSIPATING
BY MID MORNING. STILL LOOKS LIKE AT LEAST SCT COVERAGE REDEVELOPS
DURING THE AFTERNOON IN INCREASING INSTABILITY. WE MAY END UP WITH
SCT COVERAGE OVER NE GA/UPSTATE...ESPECIALLY IF AN OUTFLOW BOUNDARY
FROM THE MORNING CONVECTION MOVES THRU. HOWEVER...NOT CONFIDENT ENUF
OT UP POP ATTM.
PREVIOUS DISCUSSION...REGIONAL RADAR CONTINUES TO SHOW MCS
CONVECTION MOVING TOWARD THE AREA FROM NE TN/SW VA. THERE IS A SLY
TRAJECTORY TO THE CONVECTION AND CORFIDI VECTORS INDICATE THE
CONVECTION COULD SLIDE INTO THE NRN MTNS AND FOOTHILLS. HAVE GONE
WITH SCT CONVECTION MOVING INTO THAT AREA...BUT DISSIPATING BEFORE
MOVING OUT OF THE BLUE RIDGE. THE TRAJECTORY OF THE CONVECTION
BEHIND THE INITIAL MCS IS CURRENTLY ENE. THEREFORE...DISSIPATE THE
INITIAL CONVECTION AFTER DAYBREAK... BEFORE DEVELOPING CONVECTION
OVER THE AREA AGAIN DURING THE AFTERNOON AS INSTABILITY DEVELOPS.
THE GUIDANCE IS NOW INDICATING INSTABILITY ACROSS THE NC FOOTHILLS
AND PIEDMONT AS WELL AS THE MTNS. THEREFORE...HAVE UPPED COVERAGE TO
SCT FOR ALL OF NC. KEPT CONVECTION ISOLATED OVER SC AS THERE IS
INSTABILITY THERE...BUT LESS IN THE WAY OF LOW LEVEL FORCING FOR
INCREASED COVERAGE. CANNOT RULE OUT ISOLATED SVR STORMS...MAINLY
ACROSS THE MTNS...WITH LOW WET BULB ZERO LEVELS AND SOME DCAPE
DEVELOPING. HIGHS LOOK TO BE A TAD COOLER THAN PREV FCST...BUT STILL
ABOUT 10 DEGREES ABOVE NORMAL.
CONVECTION WILL LINGER INTO THE EARLY EVENING...BUT DISSIPATE DURING
THE LATE EVENING WITH LOSS OF HEATING. LOW LEVEL SELY FLOW DEVELOPS
OVERNIGHT. WITH CONTINUED COPIOUS LOW LEVEL MOISTURE...EXPECT
ISOLATED SHOWERS TO LINGER ALONG THE BLUE RIDGE EVEN AFTER MIDNIGHT.
THIS WILL ALSO LEAD TO CONTINUED CLOUDINESS. LOWS SHUD BE 10 TO 15
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AT 230 AM EST WEDNESDAY...AN UPPER RIDGE WIL BE OFF THE EAST COAST
ON THURSDAY...WITH A TROUGH OVER THE PLAINS. BY FRIDAY MORNING...
THE TROUGH WILL BE OVER THE MS RIVER VALLEY. ON FRIDAY NIGHT THE
TROUGH WILL START TO DEAMPLIFY OVER THE CENTRAL AND SOUTHERN
APPALACHIANS.
A MOIST SOUTHEASTERLY FLOW WILL BE OVER GA AND THE CAROLINAS ON
THURSDAY IN ADVANCE OF A COLD FRONT MOVING INTO THE MS RIVER VALLEY.
THE MODELS SHOW RATHER LIMITED INSTABILITY DURING THE DAY...MAINLY
OVER THE MOUNTAINS AND THE PIEDMONT. AS THE FRONT CROSSES THE TN
RIVER VALLEY FRIDAY NIGHT...MOIST INFLOW INCREASES WITH A TIGHTENING
PRESSURE GRADIENT...SUPPORTING INCREASING POPS. INSTABILITY WILL
WANE IN THE EVENING..THEN INCREASE TOWARD DAYBREAK IN THE
MOUNTAINS...COINCIDING WITH MODERATE SHEAR. BY MIDDAY FRIDAY THE
FRONT WILL BE ALONG THE INTERSTATE 85 CORRIDOR...BY WHICH TIME THE
MODEL SHOW THE BEST INSTABILITY OUT AHEAD OF THE BEST HELICITY...
ALTHOUGH ENOUGH OVERLAP IS PRESENT TO BE OF CONCERN. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT UNTIL FRIDAY...WHEN CLOUDS
AND PRECIPITATION WILL HOLD MAXIMUMS TO AROUND NORMAL.
THE FRONT WILL MOVE EAST OF OUR AREA SATURDAY EVENING...WITH A DRIER
AND COOLER AIR MASS MOVING IN FROM THE WEST OVERNIGHT. ALTHOUGH
MINIMUM TEMPERATURES WILL BE IN THE MID 30S AT HIGHER ELEVATIONS OF
THE NC MOUNTAINS... THE DRIER AIR COMBINED WITH POST FRONTAL WINDS
SHOULD PREVENT FROST FROM FORMING.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AT 230 AM EST WEDNESDAY...THE EASTERN TROUGH WILL CONTINUE TO
DEAMPLIFY OVER THE WEEKEND...WHILE ANOTHER TROUGH SLOWLY AMPLIFIES
OVER THE PLAINS. THE RESULT WILL BE A NEARLY ZONAL FLOW OVER THE
EASTERN TWO THIRDS OF THE NATION. BY MONDAY THE PATTERN AMPLIFIES...
WITH AN EAST COAST RIDGE AND CENTRAL USA TROUGH. ON TUESDAY THE
TROUGH MOVES OFF THE EAST COAST...AND THE RIDGE UPSTREAM REACHES THE
MS RIVER VALLEY.
SATURDAY AND SUNDAY FEATURE DRY HIGH PRESSURE MOVING ACROSS THE
APPALACHIANS. BY MONDAY THIS SURFACE HIGH WILL EXTEND ALONG THE
EASTERN SEABOARD...WHILE THE OLD SURFACE FRONT WILL BE STALED NEAR
THE GULF COAST. ISENTROPIC UPGLIDE OVER THIS BOUNDARY WILL SPREAD
CLOUDS AND PRECIPITATION NORTH ACROSS OUR AREA. THE SURFACE RIDGE
WEAKENS ON TUESDAY...WHILE ANOTHER COLD FRONT WILL MOVE INTO THE TN
RIVER VALLEY FORM THE WEST. MAXIMUM TEMPERATURES WILL RUN AROUND SIX
OR SEVEN DEGREES BELOW NORMAL FROM SATURDAY THROUGH TUESDAY....WHILE
MINIMUM TEMPERATURES RUN AROUND NORMAL.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP. HOWEVER...EXPECT SCT
LOW VFR WITH BKN HIGHER CLOUDS THIS MORNING AS CONVECTIVE DEBRIS
FROM THE DYING CONVECTION TO THE NW MOVES OVERHEAD. DO NOT EXPECT
THIS CONVECTION TO AFFECT THE AIRFIELD...CANNOT RULE OUT SOME
SPRINKLES THIS MORNING. OTHERWISE...LOW VFR SHUD DEVELOP DURING THE
AFTERNOON. GUIDANCE STILL SUGGESTS BETTER CHC OF CONVECTION OVER THE
PIEDMONT THIS AFTERNOON. THEREFORE...HAVE INCLUDED A PROB30 FOR LATE
AFTERNOON/EARLY EVENING. CONVECTION SHUD DIE OFF DURING THE
EVENING...BUT LOW VFR CONTINUES OVERNIGHT. HAVE KEPT IT AT VFR FOR
NOW EVEN THO SOME GUIDANCE SUGGESTING LOWER CIGS. SWLY WINDS BECOME
SLY THRU THE DAY AND SELY OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...WIDESPREAD STRATOCU DID NOT DEVELOP
BUT NEITHER DID FOG. HAVE INCLUDED EARLY PRECIP AT KAVL/KHKY TO
ACCOUNT FOR THE CURRENT CONVECTION. HOWEVER...DO NOT EXPECT ANY
RESTRICTIONS...BUT WOULD BE BRIEF IF THEY DID DEVELOP. STILL EXPECT
BETTER CHC OF CONVECTION AT KHKY/KAVL WITH ONLY SLIGHT CHC OVER THE
SC SITES. KEPT THE PROB30 GOING FOR KHKY/KAVL. CONVECTION SHUD
DIMINISH DURING THE EVENING...BUT LOW LEVEL SELY FLOW COULD KEEP
ISOLATED SHRA GOING ALONG THE BLUE RIDGE. DO NOT EXPECT ANY
RESTRICTIONS EXCEPT NEAR CONVECTION UNTIL OVERNIGHT NEAR THE BLUE
RIDGE WITH THE MOIST SELY FLOW. THEREFORE...DID BRING MVFR TO KAVL
BY MORNING. GENERALLY SWLY FLOW BECOMES SLY THEN SELY THRU THE
PERIOD.
OUTLOOK...SOUTHERLY FLOW WILL INCREASE ACROSS THE AREA ON THU. A
COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH THUNDERSTORMS AND
ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES WILL RETURN OVER THE
WEEKEND.
CONFIDENCE TABLE...
13-19Z 19-01Z 01-07Z 07-13Z
KCLT HIGH 99% HIGH 100% HIGH 100% HIGH 98%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 91%
KAVL HIGH 100% HIGH 100% HIGH 98% HIGH 88%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 86%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 91%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...RWH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1043 AM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 1042 AM CDT WED APR 17 2013
MADE A BIT OF A MODIFICATION TO THE WINTER WEATHER ADVISORY IN
THAT WE POSTPONED THE START OF THE ADVISORY FOR MUCH OF OUR
WESTERN ZONES UNTIL 00Z THIS EVENING. WE DID KEEP IT AS IS FOR
GREGORY AND BRULE COUNTIES...PRIMARILY FOR THE THREAT OF LIGHT
FREEZING DRIZZLE. WINNER CONTINUES TO REPORT SOME SORT OF LIGHT
MIXED PRECIPITATION...AND TEMPERATURES SO FAR IN SOUTH CENTRAL SD
ARE BELOW FREEZING. THAT SAID...CHAMBERLAIN AND SURROUNDING
VICINITY MAY WARM UP TO JUST ABOVE FREEZING THIS AFTERNOON. BUT
SOME EXISTING SNOW COVER IN THOSE AREAS...THE ACTUAL GROUND
TEMPERATURE MAY BE A BIT COOLER ALLOWING ANY DRIZZLE TO PARTIALLY
FREEZE ON CONTACT.
OTHERWISE...THE WARM AIR ADVECTION WHICH HELPED TO CAUSE THE
PRECIPITATION THIS MORNING IN NORTHWEST IOWA IS EXITING AT THIS
TIME. THEREFORE A BULK OF OUR FORECAST AREA IS LEFT WITH MOISTURE
STARVED MID LEVELS...SEEN BEST ON THE RAP SOUNDINGS. THERE IS SNOW
TO THE WEST OF OUR FORECAST AREA WHERE 650MB FRONTOGENESIS IS
MAXIMIZED AND WHERE THERE IS MID LEVEL MOISTURE. HOWEVER IN OUR
FORECAST AREA...THE MAXIMIZED FRONTOGENESIS IS LOWER...AROUND
750MB TO 700MB...AND CONDITIONS ARE QUITE DRY IN THAT LAYER
THROUGH MUCH OF THE AFTERNOON. IN FACT IN OUR SOUTHEAST ZONES...
THE FRONTOGENESIS WAS IN THE LOWER LEVELS EARLIER TODAY...AND THAT
TOO IS TEMPORARILY WANING. SO THINKING OF LOWERING POPS IN MANY
AREAS UNTIL 21Z AND INCLUDE DRIZZLE...THEN BEGIN TO RAMP UP THE
POPS AGAIN LATE THIS AFTERNOON AS THE NEXT WELL ADVERTISED STRONG
WAVE APPROACHES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT WED APR 17 2013
COMPLEX SET UP THIS MORNING WITH A COUPLE OF AREAS OF PRECIPITATION.
THE FIRST WAS A SNOW BAND THAT WAS VERY SLOWLY WORKING EAST INTO THE
FAR WESTERN CWA THIS MORNING. THE SOUTH AND EAST EDGE OF THIS BAND
HAS REALLY STRUGGLED TO DEVELOP BUT SOME HINTS THAT THERE WILL BE
SOME DEVELOPMENT THROUGH THE MORNING INTO THE WESTERN CWA. THE
SECOND AREA WAS ASSOCIATED WITH A POTENT AREA OF THETA E ADVECTION
AND MODERATE INSTABILITY ACROSS KANSAS. EXPECT THIS AREA TO
CONTINUE TO DEVELOP NORTHEAST THROUGH THE EARLY MORNING HOURS AND
CLIP THE SOUTHEAST THIRD OF THE CWA. WILL HAVE THUNDER OVER PARTS OF
NORTHWEST IOWA WITH DECENT ELEVATED INSTABILITY BUT NOT THINKING
SEVERE. INCREASED QPF AMOUNTS A BIT IN THESE AREAS AS WELL TO AROUND
A QUARTER TO THREE QUARTERS OF AN INCH THIS MORNING. IN BETWEEN
THESE TWO AREAS OVER EAST CENTRAL SOUTH DAKOTA AND SOUTHWEST
MINNESOTA THE POTENTIAL FOR NOT TOO MUCH ACTIVITY AS THE BAND OF
SNOW LOCKS UP TOT HE EAST TODAY AND THE CONVECTIVE ELEMENTS REMAIN
MAINLY SOUTH AND EAST. HOWEVER...ONCE THE UPPER LEVEL SUPPORT MOVES
INTO NEBRASKA TONIGHT EXPECT THIS RELATIVE BLANK SPOT TO FILL IN
QUICKLY THIS EVENING. SUSPECT MAINLY RAIN IN THE EASTERN CWA WHILE
THE WEST WILL BE MAINLY SNOW.
TONIGHT INTO THURSDAY POSES A PROBLEM FOR THE AREA WITH
FAIRLY GOOD AGREEMENT AMONGST THE VARIOUS MODELS DYNAMICALLY. THEY
ALL AGREE IN SWINGING THE STRONGEST PV ADVECTION NORTHWARD LATE
WEDNESDAY NIGHT INTO SOUTHEAST SOUTH DAKOTA THEN SHIFT IT EAST
GRADUALLY THROUGH THE DAY THURSDAY. IN FACT MEASURABLE SNOWFALL IS
PRETTY LIKELY IN THE EASTERN CWA THURSDAY EVENING. IT APPEARS THAT
THERE WILL BE A VERY STRONG MID LEVEL BOUNDARY IN PLACE WHICH WILL
COME NORTH THIS MORNING WITH THE STRONG LOW AND MID LEVEL THETA E
ADVECTION. THIS WAVE WILL BE ABLE TO INTERACT WITH THIS THERMAL
BOUNDARY AND IF THE SOUNDINGS ARE CORRECT SOMETHING CLOSE TO THE
750MB FRONT WILL YIELD THE MOST POTENT PRECIPITATION RATES AS A
PARCEL LIFTED FROM THIS LEVEL WOULD HAVE ABOUT 150 TO 300 J/KG
UNCAPPED CAPE TO WORK WITH. THERE MAY BE A SMALL RIBBON OF SLEET OR
FREEZING RAIN FROM ABOUT 22Z THROUGH 5Z BUT THIS LOOKS TO BE MORE OF
A TRANSITIONAL ISSUE VERSUS LAST WEEKS SUSTAINED PERIOD OF SLEET AND
FREEZING RAIN. SO FOR NOW NOT PLANNING ON ANY MAJOR ICE PROBLEMS AND
ONLY A BRIEF PERIOD FOR 1 TO 2 HOURS FROM ABOUT INTERSTATE 29 EAST
VERY LATE THIS AFTERNOON AND THIS EVENING. FAIRLY CONSISTENT SIGNALS
FROM THE MODELS THAT FROM ABOUT 0Z THURSDAY THROUGH 0Z FRIDAY A HALF
TO THREE QUARTERS OF AN INCH OF LIQUID WILL BE LIKELY AND MOST OF
THIS WILL FALL AS SNOW...AGAIN POSSIBLY A LITTLE SLEET TO START.
SUSPECT SNOWFALL RATIOS WILL BE LIMITED AND WILL AIM FOR AN AVERAGE
OF ABOUT 9:1 THROUGH THE EVENT...ALTHOUGH SOMETHING CLOSE TO 12:1
WILL BE POSSIBLE THURSDAY AFTERNOON. WILL ISSUE AN ADVISORY FOR
SOUTHWEST MINNESOTA INTO SOUTHEAST SOUTH DAKOTA FOR THE EXPECTED
SNOW TONIGHT INTO THURSDAY. BORDERLINE WARNING CRITERIA BUT WITH A
WET SNOW AND MELTING/COMPACTION POTENTIAL WILL LEAN TOWARDS A HIGH
END ADVISORY.
THE SNOW SHOULD WIND DOWN THURSDAY NIGHT WITH FRIDAY JUST LOOKING
WINDY AND COLD. TEMPERATURES FROM TODAY INTO FRIDAY SHOULD BE ABOUT
20 TO 25 DEGREES BELOW NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED APR 17 2013
THIS WEEKEND INTO EARLY NEXT WEEK SHOULD SEE CONTINUED BELOW NORMAL
TEMPERATURES WITH TROUGHING REMAINING OVER THE CENTRAL US. WAVE
MOVING THROUGH SATURDAY NIGHT INTO SUNDAY SHOULD BRING AT LEAST
SCATTERED SHOWERS TO THE AREA...THERMAL PROFILES LOOK WARM ENOUGH FOR
ANY PRECIP TO BE RAIN WITH THIS WAVE. HIGHS SATURDAY SHOULD MAINLY
BE IN THE 40S...COULD SEE SOME 50S ON SUNDAY AHEAD OF THE
APPROACHING COLD FRONT. THE FRONT PUSHES THROUGH SUNDAY NIGHT INTO
MONDAY RESULTING IN HIGHS BACK INTO THE 40S FOR EARLY NEXT WEEK.
RAIN SHOWER CHANCES CONTINUE SUNDAY NIGHT INTO MONDAY WITH THIS
FRONTAL PASSAGE AND DIGGING WAVE. THERMAL PROFILES SUGGEST BY LATER
MONDAY ANYTHING THAT FALLS COULD BE SNOW. HOWEVER MODELS DIFFER ON
THEIR HANDLING OF THE DIGGING WAVE...WITH THE LATEST 0Z ECMWF THE
MOST AGGRESSIVE WITH THE SYSTEM...CUTTING THE LOW OFF TO OUR SOUTH AND
GIVING PORTIONS OF OUR CWA SNOW OR RAIN ON TUESDAY. THIS IS AN
OUTLIER SOLUTION AT THIS TIME...WITH THE MORE LIKELY RESULT BEING A
MORE PROGRESSIVE WAVE AND JUST LIGHTER QPF AMOUNTS SUNDAY NIGHT INTO
MONDAY NIGHT. HOWEVER WILL HAVE TO CONTINUE TO MONITOR TRENDS ON
THIS SYSTEM. FURTHER IN THE EXTENDED...FINALLY SOME DECENT SIGNS IN
THE LONG TERM ENSEMBLES THAT WE SEE TEMPERATURES WARMING TO AT OR
ABOVE NORMAL BY AROUND THE LAST WEEKEND OF THE MONTH. OF COURSE THIS
IS STILL FAR OUT...BUT MAYBE A SIGN THAT SPRING WILL FINALLY ARRIVE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 645 AM CDT WED APR 17 2013
COMPLEX WEATHER SYSTEM WILL IMPACT THE AREA THROUGH THE TAF PERIOD.
CURRENTLY SEEING AN AREA OF MODERATE RAIN AND EMBEDDED THUNDER MOVING
ACROSS NORTHWEST IOWA. THIS AREA SHOULD EXIT TO THE EAST BY MID
MORNING. OTHERWISE THE TREND IS FOR LIGHTER PRECIPITATION TODAY WITH
SLIGHTLY HIGHER CIGS AND VIS THAN PREVIOUSLY THOUGHT. THINK AREA OF
LIGHT PRECIPITATION WILL DEVELOP LATER THIS MORNING ACROSS THE AREA.
THIS WILL BE MAINLY SNOW AT KHON...ALTHOUGH VISIBILITIES SHOULD NOT
BE IMPACTED TOO MUCH. CLOSER TO KFSD...LOOKING AT A LIGHT WINTRY
MIX...AND MAINLY RAIN AT KSUX THROUGH THE DAY. SLOWLY LOWERED CIGS
THROUGH THE DAY...WITH MVFR BECOMING DOMINANT BY AFTERNOON. ANOTHER
HEAVIER BATCH OF PRECIPITATION SHOULD FORM OVER NEBRASKA AND MOVE
INTO OUR AREA TONIGHT INTO THURSDAY. THIS SHOULD BE MAINLY SNOW AT
KFSD AND KHON...WITH LOWERING CIGS AND VIS LIKELY INTO THE IFR AND
POSSIBLY LIFR RANGE AT TIMES. KSUX SHOULD SEE THIS BEGIN AS RAIN AND
TRANSITION TO SNOW BY 12Z. NORTHERLY WINDS WILL ALSO PICK UP BY LATER
TONIGHT...GUSTING INTO THE 20 TO 30 KT RANGE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR SDZ038>040-052>056-058>071.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ050-057.
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR MNZ071-072-080-081-089-090-097-098.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR IAZ001-002-012-020.
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR NEZ013.
&&
$$
UPDATE...MJF
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1129 AM MDT WED APR 17 2013
.UPDATE...
&&
.SHORT TERM...OVERALL CURRENT FORECASTS SEEM ON TRACK WITH WARNINGS
AND ADVISORIES STILL LOOK REASONABLE. STRONGER WINDS ACROSS
PLAINS MAY BE DELAYED A FEW HOURS BASED ON LATEST RAP AND HRRR AND
PERHAPS NOT AS STRONG AS CURRENTLY EXPECTED. SNOW TO CONTINUE TO
SPREAD ACROSS PLAINS WHILE CONTINUING INTO THE MOUNTAINS. EXPECTED
SNOW AMOUNTS SEEM ON TRACK...MAY NEED TO ADD A FEW INCHES ACROSS
PLAINS IF HEAVIER BANDS PERSIST. MESSY AFTERNOON/EVENING COMMUTE
STILL ANTICIPATED.
.AVIATION...SNOW PERSISTING ACROSS DENVER AREA WITH OCCASIONAL
BANDS OF MODERATE TO HEAVY SNOW. MVFR CONDITIONS TO PREVAIL WITH
PERIODS OF IFR OR LIFR POSSIBLE WITH THE HEAVIER SNOW. LATEST
MODELS SHOWING LESS WIND AT KDEN...MAY NEED TO DECREASE A BIT.
STILL SOME POTENTIAL FOR BLOWING SNOW. WILL FOLLOW CURRENT TAF
TRENDS AT THIS TIME...THOUGH THE PREVAILING 1/2 MILE FROM 21Z TO
03Z MAY BE A BIT OVERDONE. WILL ADJUST THAT LATER.
&&
.PREV DISCUSSION... /ISSUED 849 AM MDT WED APR 17 2013/
UPDATE...
SHORT TERM...DOES NOT LOOK LIKE BLIZZARD CONDITIONS ARE EXPECTED
TO BE WIDESPREAD ENOUGH ACROSS MUCH OF THE PLAINS: ZONES 42..44..
48>51..TO WARRANT UPGRADING BLIZZARD WATCH TO WARNING AND WILL
HOIST A WINTER STORM WARNING THERE INSTEAD WITH THE POTENTIAL FOR
CONSIDERABLE BLOWING AND DRIFTING SNOW. WIDESPREAD BLIZZARD
CONDITIONS LOOK TO BE MORE PROMISING FOR THE PALMER DIVIDE: ZONES
41 AND 46...SO THE WATCH WAS UPGRADED THERE TO A BLIZZARD WARNING.
NO OTHER CHANGES AT THIS TIME. WILL NEED TO WATCH DENVER AREA FOR
POTENTIAL UPGRADE TO WINTER STORM WARNING. AT THIS TIME...CURRENT
ADVISORY LOOKS OKAY. NO OTHER CHANGES AT THIS TIME. LATEST
OBSERVATIONS AND WEB CAMS SHOW THAT THE MIXED BAG OF FREEZING
RAIN/DRIZZLE AND LIGHT SNOW ALONG THE URBAN CORRIDOR AND ADJACENT
PLAINS BEGINNING TO CHANGE OVER TO ALL SNOW SNOW AS THE DEEPER
MOISTURE AND MID LEVEL ASCENT HAS ARRIVED. SHOULD BE ALL SNOW
SHORTLY.
$$
AVIATION...STILL SOME FREEZING DRIZZLE BEING REPORTED AT
KBJC...WITH ALL SNOW AT KDEN AND KAPA. WITH DEEPER MOISTURE
SPREADING OVER AREA...KBJC SHOULD CHANGE OVER TO ALL SNOW IN THE
BY 16Z. MAY HAVE TO EXTEND THE FREEZING DRIZZLE POTENTIAL THERE
ANOTHER HOUR. NO OTHER CHANGES ANTICIPATED AT THIS TIME.
PREV DISCUSSION... /ISSUED 414 AM MDT WED APR 17 2013/
SHORT TERM...STILL A RATHER COMPLEX WEATHER SCENARIO FOR
NORTHEAST AND NORTH CENTRAL COLORADO. WATER VAPOR LOOP SHOWS A
DEEP BUT ELONGATED UPPER LEVEL TROUGH BEGINNING TO PUSH MORE
EASTWARD ACROSS THE GREAT BASIN AND NORTHERN ROCKIES THIS MORNING.
THERE WAS A LARGE AREA OF MODERATE Q-G VERTICAL MOTION AHEAD OF
THIS TROUGH AXIS...AND THIS WILL SHIFT EAST ACROSS THE FORECAST
AREA TODAY BRINGING WIDESPREAD SNOW.
INITIALLY...THE AIRMASS IS ONLY MOIST IN THE LOW LEVELS OVER THE
PLAINS. THIS WILL KEEP FREEZING DRIZZLE IN THE FORECAST UNTIL
DEEPER MOISTURE AND LIFT ARRIVE LATER THIS MORNING. THERE WERE
SIGNS OF THIS DEEPER MOISTURE ARRIVING FROM THE WEST...WITH
COOLING CLOUD TOPS NOTED THE LAST COUPLE HOURS OVER THE WESTERN
HALF OF COLORADO. THE DEEPER CLOUDS AND SNOW SHOULD ARRIVE ACROSS
THE FRONT RANGE FOOTHILLS BY EARLY/MID MORNING AND THEN SPREAD
EASTWARD OVER THE PLAINS LATER THIS MORNING THROUGH THE AFTERNOON.
WITH REGARD TO SNOW AMOUNTS...THE GFS AND CANADIAN WERE STILL THE
MOST AGGRESSIVE WITH SNOW ACCUMULATIONS WHILE THE NAM AND MOST
MESOSCALE MODELS FOLLOWING THE NAMS LEAD WITH LIGHTER ACCUMS. THE
ECMWF PRETTY MUCH SPLIT THE DIFFERENCE. GIVEN THE ELONGATED TROUGH
AND SOME SIGN OF SPLITTING ENERGY AS SEEN IN THE FORECAST Q-G
VERTICAL MOTION FIELDS LATER THIS AFTERNOON/EVENING...CURRENT
THINKING IS WE WILL END UP CLOSER TO THE SLIGHTLY LOWER
EC/NAM/SREF AVERAGES. DESPITE THIS...WE MAY STILL END UP WITH A
SIGNIFICANT WINTER WEATHER EVENT GIVEN A COUPLE FACTORS.
ONE...THERE IS ALREADY SNOW COVERING THE GROUND ALONG AND NORTH OF
THE I-76 CORRIDOR SO ANY NEW SNOW THAT FALLS WILL BE EASILY BLOWN
ABOUT. TWO...STRONG NORTH WINDS OF 20-30 MPH WITH GUSTS TO 40-50
MPH CAN BE EXPECTED ON THE PLAINS. THIS SHOULD CREATE CONSIDERABLE
BLOWING/DRIFTING SNOW AND NEAR BLIZZARD CONDITIONS ESPECIALLY IN
LOCALES WITH PRE-EXISTING SNOW COVER. THERE IS STILL CONSIDERABLE
UNCERTAINTY WITH REGARD TO IMPACTS AT THIS TIME SO WILL MAINTAIN
A BLIZZARD WATCH FOR THE EASTERN PLAINS WITH POSSIBLE MARGINAL
SNOW ACCUMULATIONS IN AREAS THAT HAVE LITTLE/NO PRE-EXISTING SNOW
COVER.
IN THE FRONT RANGE METRO AREAS...WINDS WILL LIKELY BE STRONG
ENOUGH TO PRODUCE CONSIDERABLE BLOWING/DRIFTING SNOW AND HIGHER
IMPACTS GIVEN EXISTING SNOW COVER AND COLDER TEMPERATURES ALLOWING
FOR MORE SNOW ACCUMULATION ON ROADS. THIS WILL VERY LIKELY DEPEND
ON SNOW INTENSITY BUT THERE IS STILL SOME POTENTIAL FOR AN UPGRADE
OF THE ADVISORY TO A WINTER STORM WARNING. THE AFTERNOON COMMUTE
LOOKS NASTY.
THE ONLY CHANGE TO CURRENT HIGHLIGHTS WILL BE TO DELAY THE START
TIME A COUPLE HOURS FOR LOCATIONS EAST OF I-25 GIVEN A SLIGHTLY
SLOWER ARRIVAL OF DEEPER MOISTURE.
LONG TERM...THE DEPARTING STORM SYSTEM WILL LEAVE THE STATE UNDER
NORTHWEST FLOW THURSDAY. SOME MOISTURE WILL STILL BE EXITING THE
STATE AND WILL LIKELY SEE SOME LIGHT SNOW REMAINING OVER THE FAR
EASTERN PLAINS IN THE MORNING AS WELL AS SOME OROGRAPHIC SNOW
LASTING OVER THE MOUNTAINS THROUGH THE AFTERNOON. TEMPERATURES
WILL STAY COLD...IN THE 30S FOR THE PLAINS AND IN THE 20S FOR THE
MOUNTAINS. NORTHERLY WINDS WILL STILL BE A BIT STRONG DURING THE
DAY...AROUND 15 TO 25 MPH WITH SOME GUSTS AS HIGH AS 40 MPH OVER
THE PLAINS...WHICH WILL CAUSE AREAS OF BLOWING SNOW. THOSE WINDS
SHOULD DIMINISH IN THE EVENING EXCEPT WHERE THEY WILL BE STAYING
GUSTY OUT OF THE WEST IN THE FOOTHILLS.
FRIDAY WILL SEE A SLIGHT WARM UP AND MAINLY DRY WEATHER...BUT
MOISTURE WILL BE INCREASING OVER THE NORTHERN MOUNTAINS LATER IN
THE DAY THROUGH THE NIGHT AS A WEAK DISTURBANCE NEARS THE STATE IN
THE NORTHWEST FLOW. TEMPERATURES SHOULD WARM SIGNIFICANTLY WITH
WARM ADVECTION MOVING IN...AND THE INTENSE APRIL SUN HELPING TO
MELT ANY REMAINING SNOW. READINGS OF UPPER 40S TO NEAR 50 OVER THE
PLAINS AND LOW TO MID 30S FOR THE MOUNTAINS ARE EXPECTED. STILL
ABOUT 10 DEGREES COOLER THAN NORMAL. THE WEAK DISTURBANCE IS
EXPECTED TO INCREASE SHOWERS OVER THE MOUNTAINS AND BRING A SLIGHT
CHANCE OF RAIN SHOWERS TO THE PLAINS SATURDAY AFTERNOON.
TEMPERATURES WILL BE SLIGHTLY WARMER THAN FRIDAY.
SUNDAY...A STRONGER DISTURBANCE WILL BE MOVING OVER THE NORTHERN
ROCKIES AND NEARING THE STATE IN THE NORTHWEST FLOW ALOFT. THIS
DISTURBANCE IS THEN EXPECTED...AS PROGGED BY THE GFS...ECMWF AND
GEM...TO DEEPEN AND DROP SOUTH OVER THE STATE BY MONDAY. THIS WILL
BRING YET ANOTHER ROUND OF COLDER TEMPERATURES AND A CHANCE OF
SNOW FORECAST AREA WIDE STARTING SUNDAY AND LASTING INTO
TUESDAY. HAVE INCREASED POPS FOR THIS PERIOD AND LOWERED
TEMPERATURES TO SHOW THIS BETTER CONFIDENCE IN THE FORECAST. SEEMS
LIKE THE ONGOING ACTIVE WEATHER PATTERN OF APRIL WILL CONTINUE
INTO NEXT WEEK.
AVIATION...LIGHT FREEZING DRIZZLE/FLURRIES WILL CONTINUE EARLY
THIS MORNING WITH MORE WIDESPREAD AND HEAVIER SNOW THEN DEVELOPING
LATE THIS MORNING INTO EARLY AFTERNOON. IFR/LIFR CONDITIONS WILL
PREVAIL. CYCLONIC CONVERGENCE ZONE WILL FLUSH SOUTH WITH ARRIVAL
OF COLD FRONT BY EARLY AFTERNOON WITH STRONGER NORTH WINDS WITH
GUSTS UP TO 30-35 KTS...STRONGEST AT KDEN. CONSIDERABLE
BLOWING/DRIFTING SNOW EXPECTED WITH STRENGTH OF WINDS. SNOW SHOULD
DECREASE AFTER 03Z-06Z WITH AN ENDING 09Z-12Z AND VFR CONDITIONS
DEVELOPING. TOTAL SNOW ACCUMULATIONS MOST LIKELY WILL BE IN THE
4-6 INCH RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MDT THURSDAY FOR COZ042-044-
045-048>051.
WINTER STORM WARNING UNTIL MIDNIGHT MDT TONIGHT FOR COZ031-033-
035.
WINTER WEATHER ADVISORY UNTIL 10 PM MDT THIS EVENING FOR COZ030-
032-034.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ036-
038-039.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ040-
043.
BLIZZARD WARNING UNTIL 6 AM MDT THURSDAY FOR COZ041-046.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MIAMI FL
150 PM EDT WED APR 17 2013
.AVIATION...VFR WILL PREVAIL. SHOWERS ARE OVER THE SOUTHERN TIP OF
THE PENINSULA AND EXPECTED TO STAY THERE WITH A SLIGHT CHANCE OF
SHOWERS, AND PERHAPS A THUNDERSTORM, ALONG THE GULF COAST, BUT
GIVEN SUCH LOW PROB`S OF TSRA, DECIDED TO JUST KEEP VCSH FOR KAPF
AND ELSEWHERE NO MENTION. NE WINDS WILL BECOME ESE ON THURSDAY
WITH SPEEDS 10-15 KT, DECREASING BY ABOUT 5 KT OVERNIGHT, THEN
BECOMING ESE AROUND 10 KT ON THU. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 957 AM EDT WED APR 17 2013/
UPDATE...
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT TO MODERATE
SHOWERS PUSHING SOUTHWEST ACROSS BISCAYNE BAY. LATEST HRRR AND
LOCAL SHORT RANGE MODELS KEEP THESE SHOWERS MAINLY ALONG AND SOUTH
OF U.S. HIGHWAY 41 THROUGH MUCH OF THE AFTERNOON. UPDATED POP AND
SKY GRIDS TO ACCOUNT FOR THIS. ALSO ADJUSTED TEMPERATURES
SLIGHTLY. UPDATE WILL BE SENT SHORTLY.
PREV DISCUSSION... /ISSUED 739 AM EDT WED APR 17 2013/
AVIATION...VFR WILL PREVAIL. A BRIEF SHOWER CANNOT BE RULED OUT
EAST COAST, BUT COVERAGE LOOKS SPARSE ENOUGH THROUGH THE PERIOD TO
PRECLUDE VCSH MENTION IN THE TAFS. HOWEVER, A GULF SEA BREEZE
DEVELOPING AT KAPF COULD ALLOW FOR A FEW SHOWERS, AND POSSIBLY A
TSTORM TO DEVELOP. FOR NOW INCLUDE VCSH THERE. WINDS WILL PREVAIL
OUT OF THE NE BECOMING EAST INCREASING TO 10-15KT THIS AFTERNOON,
EXCEPT THE SW GULF SEA BREEZE DEVELOPING AT KAPF MID AFTERNOON.
/GREGORIA
PREV DISCUSSION... /ISSUED 409 AM EDT WED APR 17 2013/
SHORT TERM (TODAY-FRIDAY)...
THE LATEST NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT
THROUGH THE SHORT-TERM PERIOD AND INDICATES THE UPPER RIDGE HOLDING
IN PLACE THROUGH TONIGHT...THEN GRADUALLY WEAKENING AND SHIFTING
EAST OVER THE WESTERN ATLANTIC AHEAD OF AN APPROACHING UPPER TROUGH
BY FRIDAY. AT THE SURFACE...THE LATEST IR LOOP AND ASCAT PASS SHOWED
A WEAK LOW CENTERED NNE OF THE BAHAMAS WITH A WEAK BOUNDARY
EXTENDING SW TOWARD SOUTH FLORIDA. THIS WEAK BOUNDARY COMBINED WITH
LIGHT EASTERLY LOW-LEVEL FLOW WILL KEEP A SLIGHT CHANCE OF MAINLY
LIGHT SHOWERS OVER THE ADJACENT ATLANTIC WATERS AND ALONG THE EAST
COAST AREAS THROUGH THE EARLY MORNING HOURS. SIMILAR TO
YESTERDAY...THE BEST CHANCE FOR AFTERNOON SHOWERS WILL REMAIN INLAND
TOWARD THE GULF COAST AS THE WEST COAST SEA BREEZE BEGINS TO
DEVELOP. THE LATEST MODEL SOUNDINGS OVER THESE INTERIOR AREAS ARE
SIMILAR TO YESTERDAY...HOWEVER...INDICATE DRIER AIR THROUGH THE
MID/UPPER LEVELS (PWAT VALUES AROUND 1.4") WITH THE BEST SOURCE OF
MOISTURE REMAINING WITHIN THE LOWER 5-10 KFT. AS A RESULT...
CONFIDENCE IN ANY DEEP MOIST CONVECTION OR THUNDERSTORM DEVELOPMENT
IS LOW. HOWEVER...A STORM OR TWO CAN NOT BE COMPLETELY RULED OUT
TODAY AS TEMPERATURES CLIMB BACK INTO THE LOWER 90S AND DEWPOINTS
REMAIN IN THE MID TO UPPER 60S. ON THURSDAY...THE LOW-LEVEL FLOW
WILL BEGIN TO SHIFT TOWARD THE SOUTHEAST...WHICH WILL TRANSLATE TO
THE BEST AFTERNOON SHOWER/TSTM CHANCES OVER THE NORTHWEST INTERIOR
OR FROM NAPLES TO THE LAKE REGION. ELSEWHERE...THE WARM CONDITIONS
WILL PERSIST WITH AFTERNOON HIGHS CLIMBING BACK INTO THE LOWER 80S
NEAR THE EAST COAST TO THE LOWER 90S INLAND. OVERNIGHT LOWS ARE
FORECAST TO RANGE FROM THE UPPER 60S INLAND TO THE LOW TO MID 70S
OVER THE EAST COAST AND METRO AREAS (SEVERAL DEGREES ABOVE THE
NORMAL LOWS) EACH NIGHT. ON FRIDAY...A COLD FRONT ASSOCIATED WITH
THE PREVIOUSLY MENTIONED UPPER TROUGH WILL BEGIN TO APPROACH THE
STATE. MOST OF THE SHOWERS/TSTM COVERAGE...HOWEVER...SHOULD REMAIN
NORTH OF OUR AREA THROUGH THE AFTERNOON PERIOD. PATCHY FOG WILL
REMAIN POSSIBLE EACH NIGHT...MAINLY OVER THE INTERIOR AREAS...WHICH
LINES UP WELL WITH THE LATEST SHORT-RANGE ENSEMBLE GUIDANCE.
LONG TERM (FRIDAY NIGHT-WEDNESDAY)...
THE EXTENDED GUIDANCE REMAINS IN DECENT AGREEMENT AND SHOWS THE
UPPER RIDGE CONTINUING TO SHIFT EAST OVER THE WESTERN ATLANTIC AS A
BROAD UPPER TROUGH SHIFTS EAST OVER THE REGION. A COLD FRONT
ASSOCIATED WITH THIS UPPER FEATURE IS FORECAST TO APPROACH AND BEGIN
TO IMPACT THE STATE OVER THE WEEKEND. INCREASING DEEP LAYER MOISTURE
COMBINED WITH THE APPROACHING FRONT/UPPER TROUGH WILL TRANSLATE TO
INCREASING RAINFALL CHANCES THROUGH THIS TIME. DEEP LAYER SOUTHWEST
FLOW WILL FAVOR ENHANCED ACTIVITY OVER THE EAST COAST
AREAS...ESPECIALLY FROM BROWARD COUNTY TO THE LAKE REGION. AS THE
FORECAST CONFIDENCE CONTINUES TO INCREASE THROUGH THE MID-WEEK
PERIOD...WE WILL BEGIN TO REFLECT THIS WITH INCREASING RAINFALL
CHANCES...ESPECIALLY FOR SATURDAY AND SUNDAY. CONFIDENCE BEYOND THIS
PERIOD INTO THE UPCOMING WEEK BEGINS TO DECREASE DUE TO SOME MODEL
DIFFERENCES. TEMPERATURES ARE FORECAST TO REMAIN AROUND OR SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD.
MARINE...
LIGHT TO MODERATE EASTERLY WINDS WILL BEGIN TO SHIFT TO THE
SOUTHEAST THURSDAY THROUGH FRIDAY AHEAD OF AN APPROACHING FRONTAL
BOUNDARY. THE COLD FRONT WILL LEAD TO INCREASING RAINFALL CHANCES
FRIDAY THROUGH THE UPCOMING WEEKEND AS THE BOUNDARY STALLS NEAR OR
OVER THE AREA. WINDS WILL SHIFT BACK TO THE EAST LATER IN THE
WEEKEND AND INTO THE UPCOMING WEEK AS THE FRONT WEAKENS AND HIGH
PRESSURE BUILDS BACK OVER THE REGION.
FIRE WEATHER...
PLENTY OF MOISTURE WITH DEWPOINTS REMAINING IN THE MID 60S WILL
KEEP RELATIVE HUMIDITIES WELL ABOVE CRITICAL LEVELS THROUGH THE
AFTERNOON PERIODS. LOW-LEVEL FLOW WILL REMAIN OUT OF THE EAST AND
SOUTHEAST WITH THE BEST CHANCE FOR AFTERNOON SHOWERS AND POSSIBLY
A STORM OR TWO REMAINING OVER THE INTERIOR LOCATIONS TOWARD THE
GULF COAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 83 74 / 10 - 10 10
FORT LAUDERDALE 82 76 84 77 / 10 - 10 20
MIAMI 84 73 85 75 / 20 - 10 10
NAPLES 88 69 88 70 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
316 PM MDT WED APR 17 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 132 PM MDT WED APR 17 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS POSITIVELY
TITLED LONGWAVE TROUGH EXTENDING SOUTH ALONG CENTRAL ROCKIES WITH
DRY SLOT/AREA OF SUBSIDENCE IN PLACE AHEAD OF THIS OVER WESTERN
KANSAS AND CENTRAL NEBRASKA. LOW AT THE SURFACE A STALLED FRONT
EXTENDS FROM THE TEXAS PANHANDLE ACROSS CENTRAL OKLAHOMA TO
SOUTHEAST KANSAS. NORTHWEST FLOW IS IN PLACE ACROSS OUR CWA WITH
VERY MOIST BL CONDITIONS PERSISTING...WHICH HAS RESULTED IN AREAS
OF FOG AND DRIZZLE PERSISTING THROUGH THE AFTERNOON HOURS. WITH
TEMPERATURES NEAR OR BELOW FREEZING...WE COULD CONTINUE TO SEE
LIGHT ICE ACCUMULATIONS ON ELEVATED SURFACES BEFORE SNOW DEVELOPS
LATER.
THE PRIMARY FORECAST FOCUS IS ON DEVELOPING WINTER STORM FOR
LATE THIS AFTERNOON THROUGH EARLY THURSDAY MORNING.
UPPER LEVEL TROUGH IS PROGGED TO SHIFT EAST THIS EVENING...WITH
LARGE SCALE ASCENT AND MID LEVEL MOISTURE OVERSPREADING THE CWA.
BROAD AXIS OF MID LEVEL FRONTOGENESIS IS EXPECTED TO SET UP ACROSS
THE NORTHWEST HALF OF OUR CWA THIS EVENING. LIGHT SNOW AND
BANDS OF MODERATE SNOW TRAINING FROM THE SOUTH TO THE NORTH. WITH
SURFACE TEMPS ALREADY BELOW FREEZING THIS AFTERNOON IN THE
NORTHWEST AND A SECOND COLD SURGE EXPECTED LATE THIS
AFTERNOON/EARLY THIS EVENING...I THINK WE SHOULD SEE A FAST
RAIN/SNOW CHANGEOVER WITH ALL SNOW IN OUR CWA THIS EVENING AND
TONIGHT. THERE IS QUITE A BIT OF SPREAD REGARDING QPF
VALUES...WITH GFS THE HIGH OUTLIER. WITH SREF (TRADITIONALLY HIGH)
AND OTHER GUIDANCE MORE IN LINE WITH PREVIOUS FORECAST QPF/SNOW
TOTALS I DISCOUNTED THE GFS SOLUTION AND ONLY MADE MINOR CHANGES
TO AMOUNTS. WE ARE CURRENTLY FORECAST 3-5 INCHES FOR MOST OF THE
AREA...WITH HIGHS AMOUNTS MORE LIKELY NORTH OF INTERSTATE 70.
OTHER CONCERN (AND POSSIBLY THE HIGHER IMPACT) IS STRONG WINDS
PROGGED TO DEVELOP THIS EVENING. ALL GUIDANCE IS SUPPORTIVE OF
GUSTY WINDS...HOWEVER GFS/MAV CONTINUES TO BE THE HIGH OUTLIER
WITH GUSTS IN EXCESS OF 60 MPH. NAM/SREF/ECMWF ALL ARE LOWER...AND
WITH BEST PRESSURE RISES ADVERTISED TO BE FURTHER SOUTH...THESE
SOLUTIONS MAY BE MORE REASONABLE. I USED A BLEND THAT FAVORED THE
NAM MIXED LAYER WINDS AND NUDGED A LITTLE TOWARDS GFS/MAV WHICH
RESULTS IN GUSTS THIS EVENING TO 50 MPH. EVEN WITH THE LOWER END
OF GUIDANCE WE SHOULD SEE BLOWING SNOW WITH REDUCED VISIBILITIES. THE
SPREAD IN GUIDANCE AND POSSIBLE LIMITED DURATION OF THE STRONGEST
WINDS IN OUR AREA RAISES QUESTIONS TO HOW LOW THESE VISIBILITIES WILL
BE AND HOW LONG. I FELT THE WINTER WEATHER ADVISORY WAS APPROPRIATE
WITH BRIEF BLIZZARD CONDITIONS POSSIBLE. IF WINDS END UP BEING MORE
IN LINE WITH GFS SOLUTION WE MAY NEED TO CONVERT WESTERN LOCATIONS TO
A BLIZZARD WARNING...CONFIDENCE JUST ISNT THERE RIGHT NOW.
THE WORST CONDITIONS SHOULD BE 03Z THROUGH ABOUT 09Z TONIGHT...WITH
SNOW ENDING QUICKLY FROM THE WEST TO THE EAST EARLY THU MORNING.
WE COULD SEE LINGERING SNOW INTO THU IN OUR NORTHEAST...HOWEVER
WITH BEST FORCING/MOISTURE OUTSIDE OUR AREA I AM NOT ANTICIPATING
VERY MUCH ADDITIONAL ACCUMULATION. WE SHOULD SEE ANOTHER BLUSTERY
DAY THURSDAY WITH HIGHS IN THE 30S AND GUSTY WINDS THROUGH THE
DAY. GFS/MAV IS AGAIN MUCH HIGHER ON WINDS THU AND MIGHT SUPPORT
ADVISORY CRITERIA. I WILL HAVE TO SEE WHAT KIND OF BIAS THE GFS
HAD TONIGHT TO HAVE ANY ANY CONFIDENCE IN THE HIGHER WINDS THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 PM MDT WED APR 17 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA.
THURSDAY NIGHT...SYSTEM THAT WILL HAVE BROUGHT THE AREA SNOW AND
WIND WILL CONTINUE TO MOVE AWAY. MODERATE GRADIENT CONTINUES THROUGH
THE NIGHT AND LOOKS LIKE THE WINDS WILL STAY UP ENOUGH TO KEEP THE
TEMPERATURES FROM BOTTOMING OUT.
FRIDAY/FRIDAY NIGHT...RIGHT REAR QUADRANT OF UPPER JET GOES ACROSS
THE NORTHERN PORTION OF THE AREA DURING THE DAY. AT THIS TIME WITH
A LARGE DRY LAYER IN THE LOW AND MID LEVELS...THIS ONLY LOOKS LIKE
IT WILL SPREAD CLOUDS ACROSS THE AREA. DURING THE NIGHT...THE LEFT
FRONT QUADRANT IS NEAR OR JUST SOUTHWEST OF THE SOUTHWEST PORTION OF
OUR AREA. AS IT LOOKS THE MAIN MID LEVEL LIFT LOOKS TO STAY TO NORTH
AND SOUTH OF THE AREA. ALSO PROBLEM AGAIN LOOKS TO BE A LACK OF
MOISTURE IN THE LOW LEVELS. SO WILL KEEP THIS PERIOD DRY AS WELL.
CLOUDS WILL DECREASE THROUGH THE NIGHT WITH THE MODELS SHOWING A
HIGHLY VARIABLE WIND FIELD AND DISAGREE WITH EACH OTHER. WILL TEND
TOWARD THE COOLER SIDE.
SATURDAY...MAIN JET REMAINS SOUTH AND WEST OF THE AREA. HIGHER LEVEL
CLOUD COVER INCREASES THROUGH THE DAY AS A COUPLE DIFFERENT SHORTWAVE
TROUGHS MOVE THROUGH. THIS MAY HINDER THE TEMPERATURES. HOWEVER...
MODELS HAVE BEEN MISSING THE BOAT ON TEMPERATURES HERE RECENTLY. HAVE
A LIGHT AND VARIABLE WIND FIELD WHICH ALSO DOES NOT BODE WELL FOR
GOING TOO WARM. MODELS HANDLE THIS DIFFERENTLY DUE TO THE DIFFERENT
HANDLING OF THE INCOMING SYSTEM. 700 TO 500 MB PATTERN WOULD
DEFINITELY SUPPORT AN EARLIER SURFACE TROUGH/FRONTAL PASSAGE. MORE
SUPPORT FOR GOING WARMER SO DID NUDGE UP TEMPERATURES A LITTLE BUT
NOT A LOT OF CONFIDENCE IN THIS DUE TO RECENT TEMPERATURE
PERFORMANCE.
NOT A LOT OF SURFACE CONVERGENCE WITH THIS WIND FIELD. PLUS ALL THE
MOISTURE LOOKS TO BE ABOVE 700 MB. SO WILL KEEP THIS PERIOD DRY.
SATURDAY NIGHT THROUGH WEDNESDAY...IN GENERAL THE MODELS ARE
CAPTURING THE OVERALL PATTERN. THE MODELS DROP A SYSTEM INTO THE
NORTH CENTRAL PORTION OF THE COUNTRY SUNDAY INTO MONDAY AND THEN
BRING THE UPPER TROUGH THROUGH AROUND TUESDAY AND THEN EAST OF THE
AREA. HOWEVER...THEY ARE DIFFERING ON THE TIMING OF THE NUMEROUS
SHORTWAVE TROUGHS THAT MOVE THROUGH IN THE WESTERLY FLOW ALOFT PRIOR
TO THE UPPER TROUGH MOVING THROUGH. THEY ALSO DIFFER IN HOW FAR SOUTH
AND HOW FAST THEY TAKE THE UPPER TROUGH THROUGH.
SO IN GENERAL THEY AGREE ON MAKING IT WET BUT NOT THE TIMING. THE
BIGGEST PROBLEM ON TIMING CENTERS AROUND TUESDAY. THE ECMWF TAKES
THE UPPER TROUGH THROUGH SOONER THAN THE GFS AND CANADIAN. SO DID
NOT HAVE ANY PROBLEM WITH WHAT THE CRH INIT GAVE ME WHICH IS
RAMPING UP POPS SUNDAY NIGHT WITH THE HIGHEST POPS MONDAY INTO
MONDAY NIGHT. FOR TUESDAY THE INIT GAVE ME POPS IN THE MIDDLE OF
THE TWO CAMPS AND COULD LIVE WITH THAT. AFTER TUESDAY IT LOOKS DRY.
STRONG COLD FRONT COMES THROUGH LATE SUNDAY NIGHT INTO EARLY MONDAY
MORNING. PER THIS RATHER FAST FRONTAL PASSAGE AND COLLABORATION
CHOSE TO LOWER MONDAY AND TUESDAY MAXES FROM WHAT THE CRH INIT GAVE
ME. OTHERWISE MADE NO OTHER CHANGES
THANKS TO ALL FOR THE COLLABORATION
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1127 AM MDT WED APR 17 2013
THIS AFTERNOON...LOW STRATUS/IFR CIGS WILL PERSIST THROUGH THE
AFTERNOON...WITH LIFR VIS AT KGLD ASSOCIATED WITH DENSE
FOG/FREEZING DRIZZLE. SHORT RANGE GUIDANCE CONTINUES TO INDICATE
VIS IMPROVING EARLY THIS AFTERNOON...HOWEVER WITH NE FLOW AT THE
SURFACE AND MOIST BOUNDARY LAYER I ADJUSTED TAFS TO INDICATE
LINGERING LIFR CONDITIONS AT KGLD THROUGH 21Z WHEN SNOW OVER
EASTERN COLORADO SPREADS EAST AND SHOULD HELP MIX OUT THE LOW
LEVELS.
THIS EVENING-THURSDAY...WINTER STORM STILL EXPECTED TO IMPACT BOTH
TERMINALS STARTING THIS EVENING WITH LOW VIS ASSOCIATED WITH
SNOW/BLOWING SNOW EXPECTED THROUGH EARLY THURSDAY MORNING. LIGHT
SNOW/BLOWING SNOW MAY LINGER LONGER AT KMCK AS UPPER LEVEL SYSTEM
MOVES EAST. OVERALL VIS SHOULD IMPROVE TO VFR AT BOTH TERMINALS BY
SUNRISE...WITH CIGS IMPROVING TO MVFR BY MID MORNING THURSDAY.
&&
.CLIMATE...
ISSUED AT 330 AM MDT WED APR 17 2013
RECORD LOW HIGH TEMPERATURES IN JEOPARDY THURSDAY:
GOODLAND.....38 DEGREES
HILL CITY....47 DEGREES
MCCOOK.......35 DEGREES
BURLINGTON...35 DEGREES
YUMA.........36 DEGREES
COLBY........39 DEGREES
TRIBUNE......40 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR KSZ001>004-013>016-027>029-
041-042.
CO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MDT
THURSDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...DR
CLIMATE...JTL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
344 PM CDT WED APR 17 2013
...UPDATED SYNOPSIS AND SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 343 PM CDT WED APR 17 2013
THE 12Z UPPER AIR ANALYSIS SHOWED A DEEP TROUGH EXTENDING FROM THE
NORTHERN ROCKIES INTO THE GREAT BASIN. A 150+ KNOT UPPER LEVEL JET
WAS IN THE BASE OF THE TROUGH OVER SOUTHERN ARIZONA AND NEW MEXICO.
AT THE 850 MB LEVEL...LOW PRESSURE WAS CENTERED OVER NORTHERN NEW
MEXICO. EAST OF THE LOW...A NEARLY STATIONARY FRONTAL BOUNDARY
EXTENDED EAST ACROSS THE NORTHERN TEXAS PANHANDLE INTO SOUTH CENTRAL
AND EASTERN KANSAS. AT THE SURFACE...THE FRONTAL BOUNDARY EXTENDED
FROM EASTERN NEW MEXICO ACROSS WEST TEXAS AND THEN NORTHEAST ACROSS
CENTRAL OKLAHOMA. WARM AND MOIST AIR WAS STREAMING NORTH ACROSS
TEXAS INTO THE CENTRAL PLAINS AND WAS CONTRIBUTING TO A VERY
UNSTABLE AIRMASS ACROSS OKLAHOMA INTO SOUTH CENTRAL AND SOUTHEAST
KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 343 PM CDT WED APR 17 2013
THERE WILL BE A CONTINUED THREAT FOR SEVERE WEATHER OVER SOUTH
CENTRAL KANSAS THIS EVENING. THE NAM IS INDICATING THAT THE 850 MB
FRONTAL BOUNDARY WILL BE IN THE AREA FROM COLDWATER AND MEDICINE
LODGE TO ST JOHN THIS EVENING BEFORE SHIFTING SOUTH OF THE AREA BY
MIDNIGHT. RAP MODEL SOUNDINGS SHOW AROUND 1500 J/KG OF ELEVATED CAPE
IN THAT AREA. AS THE SOUTHWESTERN U.S. UPPER JET PROPAGATES EASTWARD
INTO THE SOUTHERN PLAINS THIS EVENING...INCREASING UPWARD VERTICAL
MOTION COULD AID IN THE DEVELOPMENT OF ADDITIONAL THUNDERSTORMS.
THERE WILL BE A THREAT FOR HAIL UP TO QUARTER SIZE IN THAT AREA.
THE UPPER TROUGH MOVES EAST OUT OVER THE HIGH PLAINS TONIGHT. MODEL
SOUNDINGS ARE INDICATING SATURATED CONDITIONS GENERALLY BELOW 700 MB
THROUGH THE NIGHT WITH THE LEVELS ABOVE 700 MB SATURATING FOR A 3-6
HOUR TIME FRAME DURING THE NIGHT. LOCATIONS FARTHER WEST ACROSS
WESTERN KANSAS WILL SEE AREAS OF DRIZZLE CONTINUING ALONG WITH A
CHANCE FOR RAIN SHOWERS. THERE WILL BE A TRANSITION FROM RAIN TO
SNOW WITH A PERIOD OF SLEET/FREEZING RAIN POSSIBLE IN BETWEEN. THE
ATMOSPHERE SHOULD COOL OFF ENOUGH FOR SNOW TO DEVELOP OVER WEST
CENTRAL KANSAS DURING THE EVENING HOURS WITH THIS SPREADING INTO
CENTRAL KANSAS AFTER MIDNIGHT. GIVEN THE SHORT WINDOW OF OPPORTUNITY
FOR THE SEEDER/FEEDER MECHANISM TO OCCUR...DO NOT EXPECT SNOW
AMOUNTS TO BE SIGNIFICANT WITH ONLY SOME LIGHT ACCUMULATIONS
POSSIBLE ON GRASSY AREAS. AM NOT ANTICIPATING ANY SIGNIFICANT ICE
ACCUMULATIONS TO OCCUR ALTHOUGH SOME ELEVATED SURFACES COULD GET
SOME LIGHT COATINGS.
AS COLD AIR ADVECTION INCREASES...STRONG NORTHERLY WINDS DEVELOP
OVER THE WESTERN HIGH PLAINS AND SPREAD EASTWARD TONIGHT. LOW LEVEL
WINDS THROUGH THE 850 MB LEVEL INCREASE TO 40-50 KNOTS OVERNIGHT
WHICH SHOULD SUPPORT WIND ADVISORY CRITERIA WINDS LATER TONIGHT INTO
THURSDAY MORNING. HAVE ISSUED A WIND ADVISORY FOR MIDNIGHT TONIGHT
UNTIL NOON THURSDAY FOR ALL OF SOUTHWEST AND CENTRAL KANSAS.
PRECIPITATION SHOULD BE WINDING DOWN FAIRLY QUICKLY LATE TONIGHT AND
THURSDAY MORNING AS THE UPPER SYSTEM MOVES EAST OF THE REGION.
CLOUDS SHOULD BE BREAKING UP FROM WEST TO EAST DURING THE DAY. WITH
SOME SUN...AFTERNOON HIGH TEMPERATURES MAY BE ABLE TO CLIMB INTO THE
LOWER 40S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED APR 17 2013
FRIDAY:
UPPER LEVEL WNW FLOW WILL CONTINUE ON FRIDAY. AT THE SURFACE, HIGH
PRESSURE WILL RIDGE ACROSS THE PLAINS. NORTHWESTERLY WINDS WILL
EVENTUALLY BECOME SOUTHERLY AFTER SUNSET. HIGHS WILL BE IN THE 50S
AND LOWS WILL BE IN THE 20S. NO PRECIPITATION IS EXPECTED AS DRY
FLOW ALOFT AND LACK OF BL MOISTURE CONTINUES.
WEEKEND:
AN UPPER LEVEL TROUGH WILL DIG ACROSS THE CENTRAL AND SOUTHERN
ROCKIES THROUGH THE WEEKEND. THIS WILL PROMOTE A WARM AIR ADVECTION
PATTERN DOWNSTREAM ACROSS OUR REGION. A WARM 850 HPA PLUME WILL
ADVECT OFF THE ROCKIES AND OUT ACROSS SOUTHWEST KANSAS SATURDAY.
THIS WILL FAVOR DEEP MIXING AND HIGHS IN THE UPPER 60S TO LOWER 70S.
OVERNIGHT LOWS WILL MODERATE AS WELL WITH 30S ON SATURDAY AND 40S ON
SUNDAY. TEMPERATURES AROUND 70 DEG F CAN BE EXPECTED SUNDAY AS THE
AFOREMENTIONED WARM PLUME CONTINUES ACROSS THE REGION. THERE COULD BE
A FEW SHOWERS ACROSS SC/S KANSAS IN ASSOCIATION WITH WARM ADVECTION
BUT CONFIDENCE IS LOW AND MODELS ARE FAIRLY LIGHT ON QPF.
NEXT WEEK AND BEYOND:
A MAJOR CHANGE IN WEATHER IS POSSIBLE MONDAY OR TUESDAY. ANOTHER TROF
DIGGING OUT OF THE NORTHERN ROCKIES WILL USHER IN THE PASSAGE OF A
SIGNIFICANT COLD FRONT. THE ECMWF IS FAIRLY COLD WITH 850 HPA
TEMPERATURES DECREASING DOWN TO -6 DEG C. BOTH THE GFS AND ECMWF
INDICATE SOME LIGHT SNOWFALL ACROSS THE REGION ASSOCIATED WITH THIS
FRONT. CONFIDENCE IS LOW FOR PRECIPITATION TYPE BUT THERE IS HIGHER
CONFIDENCE IN LOWER TEMPERATURES WITH 40S AND 50S FOR HIGHS BY
TUESDAY/WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1249 PM CDT WED APR 17 2013
A COOL MOIST UPSLOPE FLOW OVER SOUTHWEST KANSAS WILL KEEP IFR/LIFR
CIGS IN PLACE THROUGH THE REMAINDER OF TODAY INTO TONIGHT. AREAS
OF DRIZZLE WILL CONTINUE TO PREVAIL AT GARDEN CITY AND DODGE
CITY. RAIN SHOWERS WILL BE IN THE VICINITY OF HAYS THROUGH PARTS OF
THE AFTERNOON. COLDER AIR WILL MOVE INTO WESTERN KANSAS THIS
EVENING AND WILL RESULT IN AREAS OF SLEET AND SNOW DEVELOPING
BETWEEN 03Z AND 06Z. CONDITIONS SHOULD BE IMPROVING AROUND 10-12Z
WITH CIGS AND VSBYS IMPROVING INTO THE MVFR/VFR CATEGORY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 27 40 24 59 / 50 10 0 0
GCK 25 40 22 60 / 60 20 0 0
EHA 25 42 23 60 / 50 10 0 0
LBL 26 43 23 60 / 50 10 0 0
HYS 27 39 23 58 / 60 30 0 0
P28 32 44 28 60 / 60 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM MIDNIGHT CDT /11 PM MDT/ TONIGHT TO NOON CDT
/11 AM MDT/ THURSDAY FOR KSZ030-031-043>046-061>066-074>081-
084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS GOODLAND KS
132 PM MDT WED APR 17 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 132 PM MDT WED APR 17 2013
EARLY AFTERNOON WV IMAGERY AND RAP H5 ANALYSIS SHOWS POSITIVELY
TITLED LONGWAVE TROUGH EXTENDING SOUTH ALONG CENTRAL ROCKIES WITH
DRY SLOT/AREA OF SUBSIDENCE IN PLACE AHEAD OF THIS OVER WESTERN
KANSAS AND CENTRAL NEBRASKA. LOW AT THE SURFACE A STALLED FRONT
EXTENDS FROM THE TEXAS PANHANDLE ACROSS CENTRAL OKLAHOMA TO
SOUTHEAST KANSAS. NORTHWEST FLOW IS IN PLACE ACROSS OUR CWA WITH
VERY MOIST BL CONDITIONS PERSISTING...WHICH HAS RESULTED IN AREAS
OF FOG AND DRIZZLE PERSISTING THROUGH THE AFTERNOON HOURS. WITH
TEMPERATURES NEAR OR BELOW FREEZING...WE COULD CONTINUE TO SEE
LIGHT ICE ACCUMULATIONS ON ELEVATED SURFACES BEFORE SNOW DEVELOPS
LATER.
THE PRIMARY FORECAST FOCUS IS ON DEVELOPING WINTER STORM FOR
LATE THIS AFTERNOON THROUGH EARLY THURSDAY MORNING.
UPPER LEVEL TROUGH IS PROGGED TO SHIFT EAST THIS EVENING...WITH
LARGE SCALE ASCENT AND MID LEVEL MOISTURE OVERSPREADING THE CWA.
BROAD AXIS OF MID LEVEL FRONTOGENESIS IS EXPECTED TO SET UP ACROSS
THE NORTHWEST HALF OF OUR CWA THIS EVENING. LIGHT SNOW AND
BANDS OF MODERATE SNOW TRAINING FROM THE SOUTH TO THE NORTH. WITH
SURFACE TEMPS ALREADY BELOW FREEZING THIS AFTERNOON IN THE
NORTHWEST AND A SECOND COLD SURGE EXPECTED LATE THIS
AFTERNOON/EARLY THIS EVENING...I THINK WE SHOULD SEE A FAST
RAIN/SNOW CHANGEOVER WITH ALL SNOW IN OUR CWA THIS EVENING AND
TONIGHT. THERE IS QUITE A BIT OF SPREAD REGARDING QPF
VALUES...WITH GFS THE HIGH OUTLIER. WITH SREF (TRADITIONALLY HIGH)
AND OTHER GUIDANCE MORE IN LINE WITH PREVIOUS FORECAST QPF/SNOW
TOTALS I DISCOUNTED THE GFS SOLUTION AND ONLY MADE MINOR CHANGES
TO AMOUNTS. WE ARE CURRENTLY FORECAST 3-5 INCHES FOR MOST OF THE
AREA...WITH HIGHS AMOUNTS MORE LIKELY NORTH OF INTERSTATE 70.
OTHER CONCERN (AND POSSIBLY THE HIGHER IMPACT) IS STRONG WINDS
PROGGED TO DEVELOP THIS EVENING. ALL GUIDANCE IS SUPPORTIVE OF
GUSTY WINDS...HOWEVER GFS/MAV CONTINUES TO BE THE HIGH OUTLIER
WITH GUSTS IN EXCESS OF 60 MPH. NAM/SREF/ECMWF ALL ARE LOWER...AND
WITH BEST PRESSURE RISES ADVERTISED TO BE FURTHER SOUTH...THESE
SOLUTIONS MAY BE MORE REASONABLE. I USED A BLEND THAT FAVORED THE
NAM MIXED LAYER WINDS AND NUDGED A LITTLE TOWARDS GFS/MAV WHICH
RESULTS IN GUSTS THIS EVENING TO 50 MPH. EVEN WITH THE LOWER END
OF GUIDANCE WE SHOULD SEE BLOWING SNOW WITH REDUCED
VISIBILITIES. THE SPREAD IN GUIDANCE AND AND POSSIBLE LIMITED
DURATION OF THE STRONGEST WINDS IN OUR AREA RAISES QUESTIONS TO
HOW LOW THESE VISIBILITIES WILL BE AND HOW LONG. I FELT THE WINTER
WEATHER ADVISORY WAS APPROPRIATE WITH BRIEF BLIZZARD
CONDITIONS POSSIBLE. IF WINDS END UP BEING MORE IN LINE WITH GFS
SOLUTION WE MAY NEED TO CONVERT WESTERN LOCATIONS TO A BLIZZARD
WARNING...CONFIDENCE JUST ISNT THERE RIGHT NOW.
THE WORST CONDITIONS SHOULD BE 03Z THROUGH ABOUT 09Z TONIGHT...WITH
SNOW ENDING QUICKLY FROM THE WEST TO THE EAST EARLY THU MORNING.
WE COULD SEE LINGERING SNOW INTO THU IN OUR NORTHEAST...HOWEVER
WITH BEST FORCING/MOISTURE OUTSIDE OUR AREA I AM NOT ANTICIPATING
VERY MUCH ADDITIONAL ACCUMULATION. WE SHOULD SEE ANOTHER BLUSTERY
DAY THURSDAY WITH HIGHS IN THE 30S AND GUSTY WINDS THROUGH THE
DAY. GFS/MAV IS AGAIN MUCH HIGHER ON WINDS THU AND MIGHT SUPPORT
ADVISORY CRITERIA. I WILL HAVE TO SEE WHAT KIND OF BIAS THE GFS
HAD TONIGHT TO HAVE ANY ANY CONFIDENCE IN THE HIGHER WINDS THURSDAY.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 345 AM MDT WED APR 17 2013
A SERIES OF WEAK SHORTWAVE TROUGHS WILL MOVE THROUGH THE CWA. AS
THE SHORTWAVES MOVE THROUGH THE AREA SATURDAY AFTERNOON THROUGH
SUNDAY AFTERNOON A CHANCE OF RAIN CAN BE EXPECTED. THE FORCING
THAT IS AVAILABLE SEEMS TO BE A LITTLE ON THE WEAK SIDE AND MUCAPE
IS NOT VERY GOOD (BELOW 200 J/KG)...HOWEVER WOULD NOT RULE OUT AN
ELEVATED ISOLATED TSTORM IN THE CWA BEHIND THE SURFACE TROUGH AXIS
SATURDAY AFTERNOON/EVENING.
MONDAY-TUESDAY NIGHT...A MORE POTENT UPPER LEVEL SHORTWAVE TROUGH
WITH A STRONG COLD FRONT WILL SWING THROUGH THE CWA ON MONDAY.
TIMING OF THE FROPA IS ALL OVER THE PLACE WITH THE MODELS...THE
ECMWF HAS IT MOVING THROUGH EARLY MONDAY MORNING WHILE THE GFS HAS
IT MOVING THROUGH LATER ON MONDAY. SINCE MODELS CAN/T COME TO A
CONSENSUS...DETERMINING PRECIP TYPE BECOMES MORE CHALLENGING MONDAY
NIGHT INTO TUESDAY MORNING...BELIEVE RIGHT NOW THAT PRECIP WILL
CHANGE FROM RAIN TO SNOW EARLY TUESDAY MORNING. ONCE THE TROUGH
MOVES THROUGH CANADIAN HIGH PRESSURE WILL SETTLE INTO THE CWA
CAUSING HIGH TEMPS TO BE COOLER IN THE MID TO UPPER 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1127 AM MDT WED APR 17 2013
THIS AFTERNOON...LOW STRATUS/IFR CIGS WILL PERSIST THROUGH THE
AFTERNOON...WITH LIFR VIS AT KGLD ASSOCIATED WITH DENSE
FOG/FREEZING DRIZZLE. SHORT RANGE GUIDANCE CONTINUES TO INDICATE
VIS IMPROVING EARLY THIS AFTERNOON...HOWEVER WITH NE FLOW AT THE
SURFACE AND MOIST BOUNDARY LAYER I ADJUSTED TAFS TO INDICATE
LINGERING LIFR CONDITIONS AT KGLD THROUGH 21Z WHEN SNOW OVER
EASTERN COLORADO SPREADS EAST AND SHOULD HELP MIX OUT THE LOW
LEVELS.
THIS EVENING-THURSDAY...WINTER STORM STILL EXPECTED TO IMPACT BOTH
TERMINALS STARTING THIS EVENING WITH LOW VIS ASSOCIATED WITH
SNOW/BLOWING SNOW EXPECTED THROUGH EARLY THURSDAY MORNING. LIGHT
SNOW/BLOWING SNOW MAY LINGER LONGER AT KMCK AS UPPER LEVEL SYSTEM
MOVES EAST. OVERALL VIS SHOULD IMPROVE TO VFR AT BOTH TERMINALS BY
SUNRISE...WITH CIGS IMPROVING TO MVFR BY MID MORNING THURSDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR KSZ001>004-013>016-027>029-
041-042.
CO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MDT
THURSDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY FROM 6 PM MDT /7 PM CDT/ THIS EVENING TO
6 AM MDT /7 AM CDT/ THURSDAY FOR NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...ALW
AVIATION...DR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS THROUGH
THURSDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1120 AM WEDNESDAY...
TODAY: FORECAST CHALLENGE REMAINS THE THREAT OF SHOWERS/STORMS. A
MESO-CONVECTIVE VORTEX NEAR KMTV...PER RADAR AND VISIBLE IMAGERY
THIS MORNING...IS FORECAST BY THE THE RAP/RUC TO DRIFT SLOWLY IN WNW
FLOW ALOFT ACROSS THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN
THROUGH 00Z. SHOWERS IN THE DEFORMATION ZONE TO THE NORTH OF THE
VORT CENTER ARE ALL THAT REMAIN...AND THESE WILL AFFECT AREAS
ADJACENT TO THE VA BORDER DURING THE NEXT SEVERAL HOURS. IN ADVANCE
OF THESE SHOWERS AND ASSOCIATED MID LEVEL CEILINGS - GENERALLY
ACROSS ALL BUT THE NW PIEDMONT - THE AIR MASS WILL DESTABILIZE WITH
STRONG INSOLATION AS TEMPERATURES RISE INTO THE LOWER TO MIDDLE
80S...AND BECOME PRIMED FOR SCATTERED STORM DEVELOPMENT WITH THE
APPROACH OF THE MCV. CORFIDI VECTORS INDICATE THE UPSTREAM MCS
MOVING INTO THE NORTHERN NC MOUNTAINS WILL ONLY GRAZE THE FAR
WESTERN AND SOUTHERN PIEDMONT AND/OR WEAKEN. GIVEN VERY WEAK
WINDS ALOFT... PRIMARILY ONLY A DISORGANIZED/PULSE SUB-SEVERE
CONVECTIVE MODE IS EXPECTED. HOWEVER...IF STORMS DEVELOP IN AN ARC
IN ADVANCE OF THE MCV AS THE HRRR SUGGESTS...MULTI-CELL MERGING OF
THE ASSOCIATED COLD POOLS...AND RELATIVELY STEEP LOW LEVEL LAPSE
RATES (AROUND 8 C/KM)...WOULD PROMOTE A MARGINALLY SEVERE WIND
THREAT.
AS OF 300 AM WEDNESDAY...
TONIGHT: ANY ONGOING CONVECTION SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING WITH AREAS OF FOG AND OR STRATUS POSSIBLE. LOWS IN
THE MIDDLE TO UPPER 50S
THURSDAY AND THURSDAY NIGHT:
AS THE UPPER TROUGH PROGRESSES SLOWLY EASTWARD INTO THE PLAINS AND
UPPER MIDWEST ON THURSDAY...RIDGE ALOFT WILL SHIFT EAST AND
OFFSHORE. A NICE 15 TO 20 KT OF ONSHORE FLOW DEVELOPS WITH ANY
CONVECTION LARGELY REMAINING ALONG THE UPSLOPE REGIME IN THE
FOOTHILLS AND MOUNTAINS WITH THE RE-EMERGENCE OF A STRONG MID-LEVEL
CAP OVER THE AREA KEEPING IT DRY. HIGHS IN THE UPPER 70S TO LOWER
80S. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THE APPROACHING COLD
FRONT WILL KEEP LOWS THURSDAY NIGHT IN THE LOWER 60S WITH AREAS OF
LOW CLOUDS/STRATUS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 310 PM WEDNESDAY...
..STORMY PERIOD ON FRIDAY AND FRIDAY NIGHT...
NWP GUIDANCE IS IN GOOD AGREEMENT ON MOVING A DEAMPLIFYING UPPER
TROUGH AND ASSOCIATED COLD FRONT ACROSS CENTRAL NC FOR THE FRIDAY
THROUGH SATURDAY PERIOD. GUIDANCE SUGGESTS THE COLD FRONT SHOULD
CROSS THE SOUTHERN APPALACHIANS AROUND OR JUST AFTER MIDDAY ON
FRIDAY AND REACH THE COASTAL PLAIN TOWARD MIDNIGHT. THE AIR MASS
AHEAD OF THE CONVECTION WILL BE CHARACTERIZED BY A MARGINALLY
UNSTABLE AIR MASS WITH CAPE VALUES OF AROUND 500-1000 J/KG. BUFR
FORECAST SOUNDINGS NOTE A CAPPING INVERSION EARLY IN THE DAY FRIDAY
WHICH ERODES BY AFTERNOON. THE STRONGEST LOW LEVEL FLOW TRANSLATES
NORTH AHEAD OF THE FRONT ACROSS WESTERN NC AND INTO THE MID ATLANTIC
BY FRIDAY EVENING. A REGION OF VERY IMPRESSIVE DEEP LAYER SHEAR
DRIVEN BY THE MID/UPPER JET THE LAGS BEHIND THE COLD FRONT. SPC HAS
MUCH OF THE REGION IN THE DAY 3 SEE TEXT AREA NOTING THE POTENTIAL
FOR SOME STRONG-SEVERE CONVECTION WITH THE MARGINAL INSTABILITY
BEING A LIMITING FACTOR. THE MOST LIKELY SCENARIO FEATURES
THICKENING CLOUD COVER ON FRIDAY WITH A BROAD LINE OF CONVECTION
INCLUDING A LEADING LINE OF DEEP CONVECTION SWEEPING ACROSS CENTRAL
NC DURING THE AFTERNOON AND OVERNIGHT. THE PRECIPITATION WILL BE
SLOW TO EXIT THE COASTAL PLAIN ON SATURDAY MORNING WITH THE DEEP
LAYER FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...SUPPORTING
A REGION OF POST FRONTAL RAIN. WILL ADD A SMALL CHANCE POP TO THE
FORECAST IN THE EAST FOR SATURDAY. HIGH TEMPERATURES WILL RANGE IN
THE UPPER 70S TO LOWER 80S ON FRIDAY AND IN THE MID 60S ON SATURDAY.
OVERNIGHT LOWS FRIDAY NIGHT WILL RANGE IN THE UPPER 40S WEST TO MID
50S EAST. -BLAES
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 310 PM WEDNESDAY...
THE NORTHERN STREAM TROUGH DRIVING MUCH OF THE WEATHER IN THE SHORT
TERM LIFTS NORTHEAST INTO THE GREAT LAKES AND EASTERN CANADA OVER
THE WEEKEND. A DEAMPLIFIED FLOW AND A BROAD TROUGH IS LEFT IN ITS
WAKE FOR THE FIRST PART OF THE WORK WEEK BEFORE THE PATTERN BECOMES
MUCH MORE AMPLIFIED AS A STRONG TROUGH DEVELOPS OVER THE UPPER
MISSISSIPPI VALLEY.
SURFACE HIGH PRESSURE OVER THE NORTHEAST WILL RIDGE INTO THE MID
ATLANTIC/CAROLINAS FOR LATE SAT THROUGH SUNDAY NIGHT. THE SENSIBLE
WEATHER WILL FEATURE COOLER THAN NORMAL TEMPERATURES WITH HIGHS IN
THE LOWER TO MID 60S ON SUN AND LOWS IN THE LOWER TO MID 40S.
A FAIR AMOUNT OF UNCERTAINTY EXISTS WITH THE WEATHER ON MONDAY AND
TUESDAY. A STALLED FRONT OFF THE COAST BUCKLES BACK TOWARD THE COAST
IN RESPONSE TO A SHORT WAVE MOVING THROUGH THE SOUTHERN STREAM. HPC
NOTED THAT CONFIDENCE IN THE EVOLUTION OF THE FEATURE IS LOW BUT THE
PATTERN WARRANTS AT LEAST SLIGHT CHC POPS AND INCREASED CLOUD COVER
DURING THE LATE MONDAY THROUGH TUESDAY AFTERNOON PERIOD. THE
GREATEST POPS WILL REMAIN FOCUSED TOWARD THE COAST. A PERIOD OF
PARTLY TO MOSTLY CLOUDY SKIES IS EXPECTED DURING THIS PERIOD WITH A
COOL NORTHEAST BREEZE.
A PERIOD OF FAIR WEATHER IS EXPECTED TUESDAY NIGHT INTO EARLY
WEDNESDAY WITH SOME SHORT WAVE RIDING AHEAD OF THE NEXT DEVELOPING
TROUGH AND COLD FRONT THAT WILL APPROACH THE AREA LATE WEDNESDAY.
THIS WILL WARRANT THE ADDITION OF SLIGHT CHANCE/CHC POPS IN THE WEST
FOR WEDNESDAY AFTERNOON. HIGHS IN THE LOW TO MID 70S ARE EXPECTED ON
WEDNESDAY. -BLAES
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM WEDNESDAY...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF PERIOD...WITH
TWO EXCEPTIONS. THE FIRST WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH SUNSET...IN ASSOCIATION WITH THE SLOW PASSAGE
OF A MID LEVEL DISTURBANCE. THE PROBABILITY OF OCCURRENCE AT
ANY PARTICULAR TERMINAL IS RELATIVELY LOW...HOWEVER...SO SHOWERS
AND/OR STORMS HAVE BEEN INCLUDED ONLY IN THE VICINITY UNTIL THE
THREAT BECOMES MORE IMMINENT. THEREAFTER...VFR WILL RULE THROUGH
AROUND 07-09Z...AFTER WHICH TIME THERE IS A MEDIUM TO HIGH CHANCE OF
EARLY MORNING FOG AND/OR STRATUS...WITH CONFIDENCE HIGHEST AT KFAY
AND KRWI (WHERE IT HAS OCCURRED RECENT MORNINGS). WINDS WILL BE
LIGHT AND VARIABLE OUTSIDE OF ANY GUSTINESS AND WIND SHIFTS
ASSOCIATED WITH STORMS.
LOOKING AHEAD: THERE IS A HIGH CHANCE OF LIFR-IFR STRATUS
TERMINAL-WIDE FRI MORNING...FOLLOWED BY A PERIOD OF MVFR CEILINGS AS
THE MOIST LAYER RISES WITH DIURNAL HEATING THROUGH FRI AFTERNOON.
SHOWERS AND STORMS -- AND ASSOCIATED SUB-VFR CONDITIONS -- WILL
BECOME WIDESPREAD LATE FRI-FRI NIGHT...AND SOME STORMS WILL BE
STRONG TO SEVERE. IFR CONDITIONS AND RAIN THEN POSSIBLE IN
ASSOCIATION WITH A MIDDLE ATLANTIC COASTAL STORM ON MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...BLAES
LONG TERM...BLAES
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
232 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND WESTWARD INTO THE CAROLINAS THROUGH
THURSDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1120 AM WEDNESDAY...
TODAY: FORECAST CHALLENGE REMAINS THE THREAT OF SHOWERS/STORMS. A
MESO-CONVECTIVE VORTEX NEAR KMTV...PER RADAR AND VISIBLE IMAGERY
THIS MORNING...IS FORECAST BY THE THE RAP/RUC TO DRIFT SLOWLY IN WNW
FLOW ALOFT ACROSS THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN
THROUGH 00Z. SHOWERS IN THE DEFORMATION ZONE TO THE NORTH OF THE
VORT CENTER ARE ALL THAT REMAIN...AND THESE WILL AFFECT AREAS
ADJACENT TO THE VA BORDER DURING THE NEXT SEVERAL HOURS. IN ADVANCE
OF THESE SHOWERS AND ASSOCIATED MID LEVEL CEILINGS - GENERALLY
ACROSS ALL BUT THE NW PIEDMONT - THE AIR MASS WILL DESTABILIZE WITH
STRONG INSOLATION AS TEMPERATURES RISE INTO THE LOWER TO MIDDLE
80S...AND BECOME PRIMED FOR SCATTERED STORM DEVELOPMENT WITH THE
APPROACH OF THE MCV. CORFIDI VECTORS INDICATE THE UPSTREAM MCS
MOVING INTO THE NORTHERN NC MOUNTAINS WILL ONLY GRAZE THE FAR
WESTERN AND SOUTHERN PIEDMONT AND/OR WEAKEN. GIVEN VERY WEAK
WINDS ALOFT... PRIMARILY ONLY A DISORGANIZED/PULSE SUB-SEVERE
CONVECTIVE MODE IS EXPECTED. HOWEVER...IF STORMS DEVELOP IN AN ARC
IN ADVANCE OF THE MCV AS THE HRRR SUGGESTS...MULTI-CELL MERGING OF
THE ASSOCIATED COLD POOLS...AND RELATIVELY STEEP LOW LEVEL LAPSE
RATES (AROUND 8 C/KM)...WOULD PROMOTE A MARGINALLY SEVERE WIND
THREAT.
AS OF 300 AM WEDNESDAY...
TONIGHT: ANY ONGOING CONVECTION SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING WITH AREAS OF FOG AND OR STRATUS POSSIBLE. LOWS IN
THE MIDDLE TO UPPER 50S
THURSDAY AND THURSDAY NIGHT:
AS THE UPPER TROUGH PROGRESSES SLOWLY EASTWARD INTO THE PLAINS AND
UPPER MIDWEST ON THURSDAY...RIDGE ALOFT WILL SHIFT EAST AND
OFFSHORE. A NICE 15 TO 20 KT OF ONSHORE FLOW DEVELOPS WITH ANY
CONVECTION LARGELY REMAINING ALONG THE UPSLOPE REGIME IN THE
FOOTHILLS AND MOUNTAINS WITH THE RE-EMERGENCE OF A STRONG MID-LEVEL
CAP OVER THE AREA KEEPING IT DRY. HIGHS IN THE UPPER 70S TO LOWER
80S. STRENGTHENING SOUTHERLY FLOW IN ADVANCE OF THE APPROACHING COLD
FRONT WILL KEEP LOWS THURSDAY NIGHT IN THE LOWER 60S WITH AREAS OF
LOW CLOUDS/STRATUS POSSIBLE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM WEDNESDAY...
A DEAMPLIFYING UPPER TROUGH WILL CONTINUE TO PUSH EAST THROUGHOUT
THE DAY ON FRIDAY...PROPELLING A TRAILING COLD FRONT THROUGH THE
REGION FRIDAY/FRIDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL ACCOMPANY
THIS SYSTEM AS IT MOVES ACROSS CENTRAL NC AND THE MAIN CONCERN
CONTINUES TO BE THE POTENTIAL FOR SEVERE WEATHER. MODELS ARE IN
DECENT AGREEMENT WITH THE LINE OF SHOWERS AND THUNDERSTORMS MOVING
ACROSS CENTRAL NC FROM WEST TO EAST LATE FRIDAY AFTERNOON THROUGH
EARLY SATURDAY MORNING. AS IS COMMONLY THE CASE...PLENTY OF SHEAR
WILL BE IN PLACE...BUT THE AMOUNT OF INSTABILITY WILL BE THE MAIN
LIMITING FACTOR. MODELS CONTINUE TO PROG ONLY WEAK/MARGINAL
INSTABILITY...LIKELY DUE TO THE EXTENSIVE CLOUD COVER EXPECTED AHEAD
OF THE APPROACHING FRONT...AS WELL AS THE MOSTLY NOCTURNAL TIMING OF
THE PRECIP (THIS SECOND POINT WILL MOSTLY COME INTO PLAY ACROSS THE
EASTERN PORTIONS OF THE FORECAST AREA). THIS WILL CONTINUE TO BE
MONITORED...AS TIMING STILL COULD CHANGE. NEVERTHELESS...WILL
CONTINUE TO MENTION THE POSSIBILITY OF STRONG TO SEVERE
STORMS...WITH THE PRIMARY THREAT BEING DAMAGING WIND...IN THE HWO.
HIGHS ON FRIDAY ARE EXPECTED TO RANGE FROM THE UPPER 70S ACROSS THE
WEST TO LOW/MID 80S FURTHER EAST. OVERNIGHT LOWS ON FRIDAY NIGHT
WILL BE DEPENDENT ON THE TIMING OF THE EXITING PRECIP AND
COMMENCEMENT OF COLD AIR ADVECTION. AT THIS TIME...IT APPEARS PRECIP
SHOULD CLEAR OUT OF AT LEAST THE WESTERN PORTIONS OF THE FORECAST
AREA BEFORE DAYBREAK AND THEREFORE AM EXPECTING TEMPS TO RANGE FROM
THE UPPER 40S/LOWER 50S ACROSS THE WEST TO MID/UPPER 60S FURTHER
EAST. CONDITIONS WILL IMPROVE THROUGHOUT THE DAY ON SATURDAY AND
WITH COLD AIR ADVECTION PERSISTING...HIGHS SHOULD GENERALLY BE IN
THE MID/UPPER 60S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...
BEHIND THE DEPARTING FRONT...HIGH PRESSURE WILL BUILD INTO THE
REGION...RESULTING IN COOLER AND DRIER WEATHER FOR THE WEEKEND.
THEN...THERE CONTINUES TO BE SOME UNCERTAINTY WITH RESPECT TO PRECIP
EARLY NEXT WEEK. THE FRONT IS PROGGED TO STALL NOT TOO FAR OFFSHORE
AND MODELS PROG A WAVE/INVERTED TROUGH THAT DEVELOPING ALONG IT
EARLY NEXT WEEK. BOTH THE GFS AND ECMWF INDICATE THIS SCENARIO
OCCURRING...BUT DIFFER ON THE TIMING OF SPREADING ANY PRECIP BACK
TOWARDS THE REGION. FOR NOW WILL MAINTAIN SLIGHT CHANCE
POPS...MAINLY CENTERED ACROSS THE EAST...BOTH MONDAY AND TUESDAY
(ALTHOUGH CONFIDENCE IS FAIRLY LOW). REGARDLESS...AS HIGH PRESSURE
RIDGES DOWN THE EASTERN SLOPES OF THE MOUNTAINS AND AN INVERTED
TROUGH DEVELOPS ACROSS THE WESTERN ATLANTIC...COOL AND MOIST
NORTHEASTERLY FLOW WILL PERSIST ACROSS CENTRAL NC. THIS WILL LEAD TO
A STRETCH OF BELOW NORMAL TEMPS...WITH HIGHS GENERALLY IN THE 60S
AND OVERNIGHT LOWS IN THE 40S EXPECTED THROUGH EARLY NEXT WEEK.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM WEDNESDAY...
MOSTLY VFR CONDITIONS ARE EXPECTED THROUGH THE 18Z TAF PERIOD...WITH
TWO EXCEPTIONS. THE FIRST WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS THROUGH SUNSET...IN ASSOCIATION WITH THE SLOW PASSAGE
OF A MID LEVEL DISTURBANCE. THE PROBABILITY OF OCCURRENCE AT
ANY PARTICULAR TERMINAL IS RELATIVELY LOW...HOWEVER...SO SHOWERS
AND/OR STORMS HAVE BEEN INCLUDED ONLY IN THE VICINITY UNTIL THE
THREAT BECOMES MORE IMMINENT. THEREAFTER...VFR WILL RULE THROUGH
AROUND 07-09Z...AFTER WHICH TIME THERE IS A MEDIUM TO HIGH CHANCE OF
EARLY MORNING FOG AND/OR STRATUS...WITH CONFIDENCE HIGHEST AT KFAY
AND KRWI (WHERE IT HAS OCCURRED RECENT MORNINGS). WINDS WILL BE
LIGHT AND VARIABLE OUTSIDE OF ANY GUSTINESS AND WIND SHIFTS
ASSOCIATED WITH STORMS.
LOOKING AHEAD: THERE IS A HIGH CHANCE OF LIFR-IFR STRATUS
TERMINAL-WIDE FRI MORNING...FOLLOWED BY A PERIOD OF MVFR CEILINGS AS
THE MOIST LAYER RISES WITH DIURNAL HEATING THROUGH FRI AFTERNOON.
SHOWERS AND STORMS -- AND ASSOCIATED SUB-VFR CONDITIONS -- WILL
BECOME WIDESPREAD LATE FRI-FRI NIGHT...AND SOME STORMS WILL BE
STRONG TO SEVERE. IFR CONDITIONS AND RAIN THEN POSSIBLE IN
ASSOCIATION WITH A MIDDLE ATLANTIC COASTAL STORM ON MONDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
340 PM CDT WED APR 17 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE CONTINUING
CHANCES FOR LIGHT SNOW ACROSS THE SOUTHERN JAMES RIVER VALLEY NOW
THROUGH TONIGHT AND INTO THURSDAY.
CURRENTLY...A DYNAMIC UPPER LEVEL LONG WAVE TROUGH WAS OVER THE
ROCKIES WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS.
MULTIPLE EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTHEAST
FROM THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDS FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA INTO NORTHERN
MINNESOTA...PROVIDING THE FOCUS AREA FOR A PERSISTENT BAND OF
LIGHT TO MODERATE SNOW OVER MY SOUTHEAST SINCE EARLIER THIS
MORNING TILL NOW. WHILE SOME ACCUMULATIONS ARE OCCURRING...THIS IS
MAINLY ON GRASSY AREAS WITH ROAD SURFACES WET THANKS TO ROAD
SURFACE TEMPERATURES AT 60F OR HIGHER.
DUE IN PART TO OUR RECENT SNOWFALL...HIGH BOUNDARY LAYER MOISTURE
REMAINS ACROSS THE LOCAL REGION RESULTING IN A PERSISTENT STRATUS
DECK STILL IN PLACE OVER MOST OF WEST AND CENTRAL NORTH DAKOTA. DO
NOT SEE THIS DISSIPATING UNTIL MAYBE TOMORROW MORNING/AFTERNOON
WHEN A S/WV RIDGE MOVES INTO THE STATE HELPING TO SCOUR OUT THE
LOW CLOUDS.
WILL CONTINUE WITH THE SPS THROUGH THIS EVENING WITH SOME
ADDITIONAL LIGHT ACCUMULATIONS POSSIBLE SOUTHEAST WITH BOTH THE
NAM AND RAP BRINGING ANOTHER S/WV NORTHEAST ACROSS PORTIONS OF THE
JAMES BASIN THIS EVENING. ALREADY SEE THIS ENHANCED AREA OF
PRECIP EAST OF THE BLACK HILLS AND WEST OF PIERRE ADVECTING
NORTHEAST. WITH NIGHTFALL...ROAD SURFACE TEMPERATURES...AS THEY
DID LAST NIGHT...WILL FALL TO AROUND FREEZING...SO ICY CONDITIONS
ARE POSSIBLE AND WILL MENTION THIS WITHIN THE SPS.
SNOW CHANCES DECREASE THURSDAY MORNING/AFTERNOON ACROSS THE
SOUTHEAST AS THE UPPER JET MIGRATES EAST AND WEAK HIGH PRESSURE
BUILDS IN ACROSS CENTRAL NORTH DAKOTA. WITH THE CLOUDS SCOURING
OUT AND WITH THE S/WV RIDGE PROVIDING SOME WAA...HAVE FORECAST
HIGHS THURSDAY NEAR 40 WEST. 30S CENTRAL AND EAST WITH A MODERATE
NORTH FLOW REMAINING IN PLACE ALONG WITH A LONGER DURATION OF
CLOUDS.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 PM CDT WED APR 17 2013
NO SIGNIFICANT STORMS IN THE LONG TERM PERIOD...HOWEVER EXPECT AN
ACTIVE PERIOD THROUGH SUNDAY AS PERIODIC CHANCES FOR SNOW/SLEET/RAIN
OCCURS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THIS WILL RESULT IN
A COUPLE OF INCHES OF MORE SNOW TO ACCUMULATE ESPECIALLY OVER NORTH
CENTRAL NORTH DAKOTA THROUGH SUNDAY. H5 PATTERN FOR MID TO LATE NEXT
WEEK STILL IN GOOD AGREEMENT WITH ESTABLISHING A H5 RIDGE OVER THE
NORTHERN ROCKIES WITH A GRADUAL MODERATING TREND AS DENOTED IN THE
H85 TEMPERATURES ACROSS MONTANA INTO WESTERN AND CENTRAL NORTH
DAKOTA.
BEGINNING THURSDAY NIGHT...A WEAK ALBERTA CLIPPER SYSTEM SLIDES INTO
NORTHWEST NORTH DAKOTA THURSDAY NIGHT AND INTO SOUTH CENTRAL NORTH
DAKOTA 12Z FRIDAY. SHORT RANGE MODELS SHOW A BAND OF LIGHT SNOW OR
POSSIBLY A WINTRY MIX ORIENTED NORTHWEST TO SOUTHEAST WITH UP TO
ONE INCH OF SNOW IN NORTH CENTRAL NORTH DAKOTA...FROM BOWBELLS TO
STANLEY...EAST TO MINOT AND SHERWOOD. PERHAPS A DUSTING COULD OCCUR
ELSEWHERE IN CENTRAL NORTH DAKOTA. LINGERING LIGHT SNOW CONTINUES
INTO FRIDAY MORNING WITH THE LOW EXITING FRIDAY AFTERNOON. EXPECT A
BRIEF PERIOD OF DRY WEATHER FRIDAY AFTERNOON INTO A PORTION OF
FRIDAY NIGHT.
FRIDAY NIGHT/SATURDAY/SUNDAY...SURFACE LOW PRESSURE/WARM FRONT IN
EASTERN MONTANA WILL PROGRESS EAST...RESULTING IN DECENT ISENTROPIC
ASCENT ON THE 285K-295K PRESSURE SURFACES. THIS PRODUCES HIGH
CHC/LIKELY POPS BY LATE FRIDAY NIGHT WEST...AND SPREADING INTO
CENTRAL NORTH DAKOTA SATURDAY. WARMER TEMPERATURES ALOFT WILL RESULT
IN RAIN ACROSS SOUTHWEST NORTH DAKOTA SATURDAY...WITH LIGHT SNOW
ELSEWHERE. WIDESPREAD SNOWFALL ACCUMULATIONS OF UP TO ONE INCH WILL
BE COMMON...WITH A COUPLE OF INCHES FAVORING NORTH CENTRAL NORTH
DAKOTA. ABOVE FREEZING ROAD TEMPERATURES DURING THE DAYLIGHT HOURS
SHOULD ALLOW FOR MELTING...WITH SNOWFALL ACCUMULATIONS MAINLY ON THE
GRASSY AREAS.
FOR MONDAY...A NORTHERN STREAM UPPER LOW/TROUGH FOLLOWS...AND DIGS
INTO WESTERN NORTH DAKOTA WITH A PRECIPITATION THREAT REMAINING
WEST...SOUTH...AND EAST OF THE FORECAST AREA. THIS LOW EJECTS OUT
LATE TUESDAY WITH A BUILDING H5 RIDGE DEVELOPING ALONG THE WEST
COAST. THIS RIDGE SLOWLY SIDES EAST INTO THE NORTHERN ROCKIES
WEDNESDAY THROUGH FRIDAY WITH A GRADUAL WARMUP. ABOVE AVERAGE
TEMPERATURES LIKELY IN THE WEST BY LATE NEXT WEEK. THIS SHOULD ALSO
PROMOTE A GENTLE MELT OF THE SNOWPACK UNDER A DRY WEATHER REGIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 340 PM CDT WED APR 17 2013
WIDESPREAD MVFR STRATUS WILL PERSIST TONIGHT...ALONG WITH AREAS OF
IFR CIGS. SHOULD SEE THE STRATUS START TO DISSIPATE THURSDAY
MORNING/AFTERNOON...ESPECIALLY WEST INTO NORTH CENTRAL...AS AN
AREA OF HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. A LINGERING
THREAT FOR LIGHT SNOW AND MVFR-IFR VIS PERSIST AT KJMS...WITH THE
CHANCES FOR LIGHT SNOW ENDING BY EARLY AFTERNOON THURSDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NH
LONG TERM...KS
AVIATION...NH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1208 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 1205 PM CDT WED APR 17 2013
ADJUSTMENTS TO POPS WERE THE MAIN CHANGES FOR THIS UPDATE...BASED
ON LATEST REGIONAL RADAR IMAGERY. NEAR TERM MODELS ARE HAVING
DIFFICULTIES TO SAY THE LEAST WITH SEVERAL SMALL-SCALE EMBEDDED
WAVES MOVING ACROSS THE REGION IN SOUTHWEST FLOW ALOFT. SURFACE
HIGH PRESSURE OVER THE REGION IS ALSO ACTING TO SUPPRESS
PRECIPITATION ACTIVITY TO SOME DEGREE. MAIN AREA OF LIGHT SNOW
REMAINS OVER MY SOUTHEAST...BUT DID SCALE BACK THERE FOR AN HOUR
OR TWO MID MORNING. ANOTHER EMBEDDED WAVE VIA THE RAP IS LIFTING
THROUGH CENTRAL SOUTH DAKOTA...AND HAS ACTED TO ENHANCE THE SNOW
BAND ONCE AGAIN THE LAST HOUR WITH LIGHT SNOW SPREADING
SLOWLY/SLIGHTLY NORTH ONCE AGAIN. WILL CONTINUE TO ADJUST POPS AS
NEEDED.
UPDATE
ISSUED AT 940 AM CDT WED APR 17 2013
INCREASED POPS TO CATEGORICAL SOUTHEAST TO ACCOUNT FOR MODERATE TO
HEAVY SNOW BAND STRETCHING FROM FAR NORTH CENTRAL SOUTH DAKOTA
THROUGH MY SOUTHEASTERN COUNTIES INTO FARGO. SNOW IS NOT
ACCUMULATING ON ROAD SURFACES...BUT HAVE HAD REPORTS OF 2 INCHES
OF WET SNOW ON GRASSY AREAS WITH 1-3 MORE EXPECTED. OPTED TO
CONTINUE WITH THE SPECIAL WEATHER STATEMENT WITH IMPACTS MINIMAL
AFTER CALLING STATE RADIO...LOCAL LAW ENFORCEMENT...AND EMERGENCY
MANAGERS. LOWERED/MODIFIED POPS ELSEWHERE QUITE A BIT WITH LITTLE
IF ANYTHING OCCURRING.
UPDATE ISSUED AT 652 AM CDT WED APR 17 2013
AREAS OF FOG HAVE DEVELOPED ACROSS SOUTHWESTERN NORTH DAKOTA THIS
MORNING. FURTHERMORE...PATCHY FOG HAS DEVELOPED ACROSS NORTH
CENTRAL NORTH DAKOTA IN THE VICINITY OF THE TURTLE MOUNTAIN
REGION. AS A RESULT...UPDATED THE FORECAST TO ADD AREAS OF FOG
SOUTHWEST AND PATCHY FOG NORTH CENTRAL UNTIL 15Z. THE REMAINING
FORECAST ELEMENTS ARE IN GOOD SHAPE. THE UPDATED GRIDDED AND TEXT
PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CDT WED APR 17 2013
MAIN FORECAST HIGHLIGHT IN THE SHORT TERM PERIOD WILL BE CHANCES
FOR LIGHT ACCUMULATING SNOWFALL SOUTH TODAY AND TONIGHT.
CURRENTLY...AN UPPER LEVEL LONG WAVE TROUGH WAS OVER THE ROCKIES
WITH SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS. SEVERAL
EMBEDDED SHORTWAVES IN THE FLOW WERE MOVING NORTH AND EAST FROM
THE BASE OF THE TROUGH ACROSS THE SOUTHERN ROCKIES INTO THE
CENTRAL AND NORTHERN PLAINS. AN UPPER LEVEL JET EXTENDED FROM THE
BASE OF THE TROUGH TO CENTRAL SOUTH DAKOTA AND PROVIDING UPPER
LEVEL SUPPORT FOR A LARGE AREA OF LIGHT SNOW THAT CONTINUED TO
DEVELOP FROM YESTERDAY AFTERNOON. AT THE SURFACE...BROAD LOW
PRESSURE WAS CENTERED OVER COLORADO/NEW MEXICO AND HIGH PRESSURE
WAS OVER SASKATCHEWAN/ALBERTA/WRN MONTANA RESULTING IN AN
EAST/NORTHEAST SURFACE WIND FLOW ACROSS MUCH OF THE NORTHERN
PLAINS.
THE AREA OF LIGHT SNOW HAD EXPANDED INTO WESTERN NORTH
DAKOTA...AND REGIONAL RADARS INDICATE THAT EITHER LIGHT SNOW OR
VIRGA (SNOW NOT YET REACHING THE GROUND) SHOULD ALREADY HAVE
REACHED INTO NEAR BISMARCK AND JAMESTOWN. THE LARGE AREA OF LIGHT
SNOW FROM SOUTHWESTERN SD INTO NORTHEASTERN SD AND SOUTHEASTERN ND
WAS ASSOCIATED WITH ONE OF THE MORE SIGNIFICANT SHORTWAVES MOVING
NORTHEASTWARD. THIS WAVE IS FORECAST TO CONTINUE MOVING NORTHWARD
AND WEAKEN AS IT CONTINUES INTO CANADA BY AFTERNOON. THUS HAVE
RAISED CHANCES OF LIGHT SNOW THIS MORNING ACROSS SOUTHERN NORTH
DAKOTA. AFTER NOON...THERE APPEARS TO BE A PERIOD IN WHICH UPPER
LEVEL SHORTWAVE ENERGY DECREASES OVER NORTH DAKOTA (THOUGH SEVERAL
WAVES STILL MOVING NORTHWARD IN THE UPPER LEVEL FLOW TO OUR SOUTH)
AND THE UPPER LEVEL JET SHIFTS EASTWARD AND WEAKENS OVER NORTH
DAKOTA. THUS KEPT HIGHER PRECIP CHANCES SOUTH OF JAMESTOWN AND
HAVE DECREASING CHANCES NORTH AND WEST.
TONIGHT ANOTHER SIGNIFICANT SHORTWAVE MOVES NORTHWARD TOWARDS THE
JAMES RIVER VALLEY OF NORTH DAKOTA. THE UPPER LEVEL TROUGH
CONTINUES MOVING EASTWARD ACROSS THE PLAINS...REACHING THE CENTRAL
DAKOTAS BY DAYBREAK THURSDAY MORNING. THE LIGHT SNOW SHOULD TAPER
OFF QUICKLY IN THE JAMES RIVER BASING BY DAYBREAK THURSDAY.
SNOWFALL TOTALS FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT ARE
FORECAST TO RANGE FROM 2 TO 3 INCHES IN MCINTOSH/LAMOURE/DICKEY
COUNTIES...TO 1 TO 2 INCHES ALONG AND SOUTH OF INTERSTATE 94 WEST
OF THE JAMES RIVER BASIN...TO LESS THAN AN INCH FOR NORTHERN NORTH
DAKOTA. SOME LOCALES IN DICKEY COUNTY MAY SEE UP TO 4 INCHES.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 343 AM CDT WED APR 17 2013
SURFACE HIGH PRESSURE BUILDING INTO WESTERN AND CENTRAL NORTH
DAKOTA WILL GENERATE DRY CONDITIONS FOR MOST OF THE REGION
THURSDAY. PRECIPITATION CHANCES WILL TAPER OFF ACROSS THE EXTREME
SOUTHEASTERN CWA THROUGH THURSDAY AFTERNOON. DRY CONDITIONS WILL
CONTINUE THROUGH FRIDAY AS HIGH PRESSURE CRESTS ACROSS THE REGION.
FRIDAY AFTERNOON TEMPERATURES WILL INCREASE TO THE UPPER 30S AND
40S. HOWEVER...THIS IS STILL ABOUT 15 DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR.
A SHORTWAVE TROUGH AND ITS ATTENDANT WARM FRONT IS PROGGED TO
ENTER WESTERN NORTH DAKOTA SATURDAY. DEPENDING ON HOW THE
THERMODYNAMIC PROFILE EVOLVES...PARTS OF WESTERN NORTH DAKOTA
COULD SEE ALL RAIN. HOWEVER...GIVEN THE MODEL SPREAD...WILL
FORECAST A CHANCE FOR A WINTRY MIX ACROSS WESTERN AND CENTRAL
NORTH DAKOTA SATURDAY. THE ATTENDANT COLD FRONT ASSOCIATED WITH
THE AFOREMENTIONED SHORTWAVE IS THEN PROGGED TO PUSH THROUGH THE
REGION LATE SATURDAY NIGHT/SUNDAY. CHANCES FOR A WINTRY MIX WILL
LINGER THROUGH THE LATE WEEKEND AS A RESULT. THE CHANCES FOR
PRECIPITATION WILL DIMINISH MONDAY AND TUESDAY AS HIGH PRESSURE
BUILDS INTO THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 652 AM CDT WED APR 17 2013
LIGHT TO MODERATE SNOW MAINLY SOUTH OF KJMS. A FEW LIGHT SNOW
SHOWERS ALSO AROUND KBIS. LITTLE IF ANYTHING ELSEWHERE AT THIS
TIME. AREAS OF MVFR CIGS AND VSBYS. EXPECT OCCASIONAL IFR AS
WELL. LIGHT SNOW SHOULD LINGER NEAR TO SOUTH OF KJMS FOR THE
ENTIRE TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...TM
AVIATION...NH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
407 PM EDT WED APR 17 2013
.SYNOPSIS...
A POTENT SPRING STORM SYSTEM WILL EJECT NORTHEAST THROUGH THE MID
MISSISSIPPI VALLEY TONIGHT THROUGH FRIDAY...BRINGING A WILD SWING
IN TEMPERATURE AND THE THREAT OF STRONG TO SEVERE THUNDERSTORMS.
VERY WARM CONDITIONS ON THURSDAY WITH GUSTY SOUTH WINDS WILL BE
FOLLOWED BY EVEN GUSTIER NORTHWEST WINDS AND TEMPERATURES SOME 30
DEGREES LOWER THAN THAN ON THURSDAY. IN THE WAKE OF THIS
SYSTEM...COOL CANADIAN HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY FOR THE WEEKEND WITH THE THREAT OF MORNING FROST AND SOME
DRY WEATHER.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
KIND OF A TRICKY NEAR TERM FORECAST. SURFACE ANALYSIS/METARS
CLEARLY SHOW A MORE SYNOPTIC SCALE WARM FRONTAL BOUNDARY LIFTING
THROUGH THE I-70 CORRIDOR RIGHT NOW WITH COOL 50S AND EASTERLY
FLOW OVER NRN OHIO/IND...AND SLY FLOW AND MILD 70S OVER SRN
OH/IND. HOWEVER...A PERSISTENT/REMNANT OUTFLOW BOUNDARY CONTINUES
TO PERCOLATE WITH CONVECTION IN A NW-SE AXIS FROM BLOOMINGTON IND
TO LOUISVILLE AND ON TO THE SOUTHEAST FROM THERE. LOCAL LAPS
ANALYSIS SHOWS THAT SURFACE BASED INSTBY HAS LEAKED NORTH OF THE
OUTFLOW BOUNDARY INTO THE TRI STATE AREA...WITH MLCAPES AROUND
1000 J/KG. HOWEVER...FLOW ATOP THE OUTFLOW BOUNDARY IS MODESTLY
WEAK FOR MID APRIL...AND SHEAR IS MARGINAL FOR ORGANIZED STORM
DEVELOPMENT /RIGHT AROUND 30KTS IN THE LOWEST 6KM/ GIVEN THE ALREADY
WEAK INSTBY. LATEST /17.12Z 4KM SPC WRF AND 17.15Z EXPERIMENTAL
3KM HRRR/ RUNS HAVE BEEN TRYING TO SUGGEST THAT ISOLD/SCT UPDRAFTS
WILL SLOWLY MOVE/DEVELOP NORTHEAST TOWARD THE TRI-STATE...MOVING
OFF THE OUTFLOW BOUNDARY BEFORE COLLAPSING SOMEWHERE IN SWRN/WRN
OH OR ERN IND. THIS SEEMS PLAUSIBLE GIVEN THE INSTBY THAT HAS
LEAKED NORTH OF THE OUTFLOW. BACKGROUND ASCENT IS VERY WEAK...THUS
FEEL ANY UPDRAFTS/STORMS WILL BE TIED CLOSELY TO THE DIURNAL
INSTBY CYCLE AND LOCALIZED CONVERGENCE NEAR THE OUTFLOW. HAVE
ALLOWED FOR A 25-30% PROBABILITY OF STORMS IN THE TRI-STATE FOR
THE NEXT 3-4 HOURS BEFORE BACKING OFF INTO LOWER PROBS FURTHER
NORTH AS THE NIGHT WEARS ON. NOT OUT OF THE REALM OF POSSIBILITIES
THAT BRIEF HAIL WOULD BE POSSIBLE WITH THE STRONGER CORES...AND
POCKET OF ELEVATED DCAPE PER SPC MESOA EVEN LENDS SUGGESTION OF A
GUSTY STORM OR TWO. CURRENT TRAJECTORY OF NON-SEVERE CORES
IMMEDIATELY WEST OF KLMK SUGGESTS THAT OWEN/CARROL COUNTIES IN A
FEW HOURS MAY HAVE SOME STRONGER STORMS TO DEAL WITH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
FOUND MODEL AGREEMENT TO BE VERY STRONG THROUGH THIS PERIOD AND
GOING FORECAST HAD LARGELY CAPTURED THE ENTIRE FCST SCENARIO
EXTREMELY WELL...THUS CHANGES WERE REALLY FOCUSED ON DETAILS OF
WINDS/TIMING OF STORMS...AND TIGHTENING UP GRADIENTS AHEAD/BEHIND
THE EXPECTED COLD FRONT TOMORROW NIGHT.
AFTERNOON GOES WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED A
VERY DYNAMIC AND COLD LONGWAVE TROUGH /-30C AT 500MB NEAR SLC AT
12Z/ OVER THE INTERMOUNTAIN WEST WITH SEVERAL IMPRESSIVE
CONVECTIVE COMPLEXES DOWNSTREAM NEAR THE ATTENDANT FRONTAL
SYSTEMS OVER THE MID MS VALLEY. HEIGHTS HAVE BEEN RISING OVER THE
OHIO VALLEY MUCH OF THE DAY BUT THAT PROCESS WILL TURN AROUND AS A
STRONG SHORTWAVE TROUGH/UPPER JET DIGS THROUGH THE LONGWAVE TROUGH
AND EJECTS INTO THE CENTRAL PLAINS...LOWERING HEIGHTS DOWNSTREAM
OVER THE OHIO VALLEY AND ALLOWING A STRONG COLD FRONT AND LOW
PRESSURE TO FURTHER ORGANIZE AND PUSH EAST TOWARD THE AREA.
POOL OF VERY WARM /+15C AT H85/ AIR JUST TO OUR SOUTHWEST WILL
LIFT NORTHWARD AS WARM MENTIONED ABOVE CONTINUES NORTH AND DEEPER
SLY FLOW IS ATTAINED. AS DYNAMICS REALLY BEGIN TO INCREASE ON
THURSDAY MORNING...LOW LEVEL WIND FIELD AND FALLING PRESSURES TO
THE WEST WILL INDUCE A POTENT WARM ADVECTION REGIME...WITH
EFFICIENT MIXING UNDER PARTLY CLOUDY SKIES. NAM/GFS SFC PRESSURE
GRADIENT MAGNITUDES AND SOUNDING ANALYSIS VALID THURS AFTN
SUGGESTS A WINDY DAY...SUSTAINED 20 TO 30 MPH WITH GUSTS TO 40
MPH...ESPECIALLY WEST OF I-71 FROM 10 AM THROUGH THE AFTN. A
LITTLE CONCERNED FOR WIND ADVISORY CONDITIONS IN OUR FAR NORTHWEST
WHICH IS A WIND PRONE AREA AND WILL BE UNDER THE STRONGEST
INFLUENCE OF THE DEVELOPING/DEEPENING SFC-850MB CYCLONE AND
ATTENDANT LOW LEVEL JET. WILL CONTINUE TO HIGHLIGHT WIND THREAT ON
HWO. MAX TEMPS SHOULD WARM CONSIDERABLY...INTO THE 80S MOST AREAS
AND WITH A MORE SELY TRAJECTORY OVER OUR EAST...THIS IS
DOWNSLOPE/DRYING OFF THE APPALACHIAN RISE AND MAY ALLOW BETTER
DEW POINT REDUCTION/WARMING. LIKELY WILL FALL A FEW DEGREES SHORT
OF RECORDS...WHICH ARE IN THE MID/UPPER 80S.
GETS VERY INTERESTING THURSDAY AFTER ABOUT 5 PM WHEN STRONG DEEP
LAYERED ASCENT AND LOW LEVEL CONVERGENCE IN VICINITY OF FRONTAL
ZONE TO THE WEST SHOULD CONTINUE TO FOSTER DEVELOPMENT OF A VERY
LONG/STRONG SQUALL LINE. THERE/S BEEN HINTS IN THE HIGHER RES
CONVECTION ALLOWING DATA THAT A FEW DISCRETE CELLS MAY FORM IN THE
WARM SECTOR OVER OUR FAR WEST LATE AFTN/EARLY EVENING AND THAT
WOULD BE PROBLEMATIC GIVEN A WEAK MLCINH FIELD /ERODED CAP/ AND
MLCAPE AROUND 1500 J/KG AMIDST VERY STRONG FLOW /SHEAR/. RIGHT NOW
AM NOT SEEING A STRONG/CONSISTENT SIGNAL THERE...SO KEEPING RAIN
CHANCES LOW THROUGH THE DAY.
AS THE EVENING WEARS ON...ADVANCING FRONTAL ZONE /OR PREFRONTAL
TROUGH/ WILL BECOME FOCUS FOR CONTINUED ADVANCEMENT AND
DEVELOPMENT OF CONVECTIVE SQUALL LINE INTO THE WFO ILN AREA
SOMETIME BETWEEN 10 PM AND 2 AM. THINK LATEST SWODY2 FROM SPC IS
REALISTIC...THAT WFO ILN WRN CWA WILL BE A TRANSITION AREA FROM A
VERY POTENT QLCS WITH SEVERE THREAT...TO A NON-LIGHTNING PRODUCING
LINE OF RAIN OR SHOWERS LATE IN THE NIGHT INTO THE EARLY MORNING HOURS ON
FRIDAY.
CLEARLY THE HIGHEST THREATS LOCALLY OF WIND ARE IN OUR FAR WEST
BEFORE CONVECTION ENTRAINS AN INCREASINGLY HOSTILE LOW LEVEL
AIRMASS /REF ABOVE COMMENT ABOUT DRYING ON SOUTH-SELY FLOW INTO ERN
AREAS/...AND SOUNDING ANALYSIS FROM A MULTITUDE OF NWP SOURCES
INDICATES ANY SURFACE BASED/NEAR SURFACE BASED INSTBY WILL BE
MINIMAL AT BEST /100 J/KG/ WEST OF I-75. PRIOR NOCTURNAL QLCS
EVENTS HOWEVER SUGGEST MLCAPE/MUCAPE IN THESE STRONGLY FORCED
EVENTS IS OVERRATED TO A DEGREE...AND GIVEN THE EXPECTED 0-1KM
SHEAR TOWARD 50KTS...THE SHAPE/ORIENTATION OF THE LOWEST 1KM TEMP
TRACE IS VERY IMPORTANT FOR QLCS COUPLETS AND/OR DAMAGING WIND
TRANSPORT TO THE SURFACE. FCST SOUNDINGS ARE HARD TO BUY INTO
GIVEN FICKLE NATURE OF BOUNDARY LAYER RESOLUTION IN NWP...BUT
ISOTHERMAL TO WEAKLY NEGATIVE LAPSE RATES INDEED SUGGESTS WE MAY
VERY WELL HAVE A THREAT FOR DAMAGING GUSTS ESP IN THE FIRST COUPLE
OF HOURS OF THE EVENT WEST OF I-75. WITH TIME...BUOYANCY REALLY
TANKS AND EXPECT THIS CONVECTIVE SYSTEM TO STRUGGLE TO OR NOT
PRODUCE LIGHTNING OVER THE ERN 1/2 OF THE FORECAST AREA LATE IN
THE NIGHT AND FRIDAY MORNING.
ALSO...WHILE WINDS MAY DECREASE EARLY IN THE EVENING...ISALLOBARIC
COMPONENT IMMEDIATELY IN ADVANCE OF THE VERY SHARP/STRONG FRONAL
ZONE WILL PROBABLY ALLOW FOR A BRIEF/RAPID INCREASE IN SUSTAINED
AND GUSTS IMMEDIATELY AHEAD OF THE SQUALL LINE.
FOR FLOOD CONCERN...SYSTEM WILL BE PROGRESSIVE AND HAVE HIGH
CONFIDENCE IN RAIN AMOUNTS REMAINING LESS THAN AN INCH IN MOST
AREAS. HEAVIEST WEST...LIGHTEST EAST. FEEL ANY FLOODING ISSUES
WOULD BE BRIEF/NUISANCE AND TIED TO AREAS OF VERY MOIST SOILS FROM
MERCER INTO HARDIN/DELAWARE COUNTIES.
FRIDAY TO BE POLAR OPPOSITE OF THURSDAY...A 30 DEGREE TEMP CHANGE
/PERHAPS MORE IN THE WEST/ FROM DAYTIME MAX TO DAYTIME MAX...WITH
MORE GUSTY WINDS AND A RAPID END TO THE RAIN WITH DRY SLOT. THINK
WIND ADVISORY MAY BECOME LIKELY IN NORTH/WEST AT SOME POINT AS SFC
CYCLONE REACHES LOWEST PRESSURES /SUB-990MB/ OVER LAKE SUPERIOR. A
VERY CHILLY/MISERABLE DAY IN COMPARISON TO THURSDAY.
ENOUGH WEAKENING IN THE MSLP GRADIENT FRIDAY NIGHT AND POTENTIAL
CLEARING TO WARRANT INSERT OF PATCHY FROST...THOUGH FOLLOWING
NIGHT LOOKS EVEN BETTER FOR FROST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
A STRONG AREA OF HIGH PRESSURE WILL BUILD IN THE MID SECTION OF THE
COUNTRY ON SATURDAY AND NOSE INTO THE GREAT LAKES AND OHIO VALLEY
REGION BY EVENING. SOUTHEAST FLOW WILL THEN GRADUALLY TURN SOUTH
AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE THROUGH LATE IN THE
FORECAST PERIOD.
MODELS ARE IN A WIDE RANGE FOR TIMING FOR THE TUESDAY/WEDNESDAY
SYSTEM. THE PREVIOUS FORECAST APPEARS TO HAVE THE BEST INITIAL
CONDITIONS BUT SOME NEIGHBORING OFFICES APPEAR HIGHER THAN I AM
WILLING TO GO WITH RAIN CHANCES OVERNIGHT TUESDAY. GIVEN THE LATEST
EUROPEAN WHICH SPINS THE SYSTEM UP IN THE MIDWEST ON TUESDAY...IT
HAS A MUCH SLOWER AND MORE DEVELOPED SYSTEM THAN THE GFS WHICH IS
INDICATING AN OPEN WAVE YET STRONG COLD FRONTAL PASSAGE EARLY
WEDNESDAY. WPC HAS THIS FRONT ON THE OTHER SIDE OF THE APPALACHIANS
AT THIS TIME WHICH APPEARS INCONSISTENT WITH THE REST OF THE
GUIDANCE I SEE.
UNTIL THE RAIN HITS WITH THE NEXT SYSTEM DAYS 6/7...TEMPERATURES
WILL BE ON THE INCREASE AND START FROM A COOLER 50S ON SATURDAY WITH
OVERNIGHT LOWS LIKELY NEEDING FROST HEADLINES. BY THIS TIME NEXT
WEEK AHEAD OF THE COLD FRONT...70S WILL BE FOUND AGAIN WITH
OVERNIGHT LOWS IN THE 50S. HAVE GONE WARMER THAN GUIDANCE AHEAD OF
THE NEXT SYSTEM BUT FEEL THAT THE FORECAST WILL CONTINUE TO BE
ADJUSTED UPWARD A LITTLE BIT EACH DAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
MAINLY MVFR CEILINGS ARE BEGINNING TO SCATTER AND SHOULD CONTINUE
TO DO SO EARLY IN THE PERIOD LEAVING VFR CONDITIONS. REMAINING
CUMULUS ARE FORECAST TO DISSIPATE BY EVENING LEAVING JUST HIGH
CLOUDS THROUGH THE REST OF THE TAF PERIOD. APPEARS THAT THERE
COULD BE ENOUGH LOW LEVEL MOISTURE FOR SOME MINOR VISIBILITY
RESTRICTIONS LATE TONIGHT THROUGH 12Z. WINDS WILL GRADUALLY VEER
THROUGH THE NIGHT. SOUTH WINDS WILL STRENGTHEN CONSIDERABLY LATE
IN THE TAF PERIOD WITH GUSTS OF 30 KT OR GREATER.
OUTLOOK...GUSTY SOUTHERLY WINDS WILL CONTINUE THROUGH LATE
THURSDAY AFTERNOON. A BRIEF PERIOD OF MVFR CEILINGS AND
VISIBILITIES ARE POSSIBLE AS SHOWERS AND THUNDERSTORMS MOVE
THROUGH LATE THURSDAY NIGHT AND EARLY FRIDAY MORNING. WEST WINDS
GUSTING TO 30 KT LIKELY FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...FRANKS
AVIATION...
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
341 PM EDT WED APR 17 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST OUT OF THE PLAINS TONIGHT AND
LIFT A WARM FRONT NORTH ACROSS THE AREA. THIS SYSTEM WILL CONTINUE
TO TRACK NORTHEAST ACROSS THE GREAT LAKES REGION ON FRIDAY...PULLING
A STRONG COLD FRONT EAST ACROSS OHIO AND WESTERN PENNSYLVANIA.
HIGH PRESSURE WILL BUILD IN FOR SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WARM FRONT/STATIONARY FRONT NEAR THE OHIO RIVER WITH LOW LEVEL ELY FLOW
ACROSS NRN OHIO. ELEVATED BAROCLINIC ZONE HOWEVER (925-850MB) IS
WELL NORTH OF THE SURFACE FRONT SHOWN BY THE RUC MODEL ACROSS NRN
INDIANA/SRN LWR MI. CAPES IN THE WARM SECTOR ARE 1-2000J/KG AND
WITH SLY FLOW OVERRUNNING THE BOUNDARY...CONVECTION IS OCCURRING
FROM NRN IL ACRS SRN LM INTO SRN LWR MI. STORM ALSO DEVELOPING IN
NRN INDIANA...MOVING INTO FAR NWRN OHIO. AS THE BAROCLINIC ZONE
LIFTS NORTH OVERNIGHT EXPECTING THE GENERATION ZONE FOR CONVECTION
TO ALSO LIFT. HOWEVER THROUGH THE EVENING CONCERNED WITH STORMS
GETTING INTO THE WESTERN/NWRN COUNTIES. WILL HAVE LIKELY POPS FAR
NORTHWEST WITH CHANCE ACROSS THE REMAINDER OF THE WESTERN COUNTIES.
EXPECTING FOCUS OF CONVECTION TO BE TO OUR NORTH AND WEST
OVERNIGHT BUT STILL KEPT CHANCE POPS FOR THE WEST HALF OF THE AREA
IN THE UNSTABLE AIR.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
AN ENERGETIC PATTERN FOR THE SHORT TERM WITH SEVERAL CONCERNS. FOR
THURSDAY...THE AREA WILL BE WELL INTO THE WARM SECTOR WITH HIGHS
FROM THE UPPER 70S TO AROUND 80. AS THE SYSTEM CONTINUES TO DEEPEN
TO OUR WEST SOUTHERLY FLOW WILL INCREASE THROUGH THE DAY. AM
CONCERNED ABOUT THE NEED FOR A WIND ADVISORY. WILL HAVE
STRONG/GUSTY WINDS IN THE FORECAST AND AN ADVISORY MAY BE NEEDED
ESPECIALLY FOR THE AFTERNOON/EVENING WITH DIURNAL HEATING AS THE
MOMENTUM MIXES DOWN. WINDS WILL REMAIN GUSTY THURSDAY NIGHT AHEAD
OF THE APPROACHING COLD FRONT HOWEVER BASED ON GUIDANCE...JUST
BELOW ADVISORY CRITERIA. STILL THE POTENTIAL FOR GUSTS COULD
REMAIN AS 850MB JET OF 70KTS WILL PASS ACROSS THE AREA. FRIDAY IN
COLD ADVECTION WINDS ARE AGAIN EXPECTED TO INCREASE BACK TO
ADVISORY LEVELS. BACK TO WEATHER...FOR THURSDAY WILL HAVE A LOW
CHANCE POP EVERYWHERE GUST GIVEN THE INSTABILITY WITH LIKELY POPS
IN THE AFTERNOON FAR NORTHWEST AS PREFRONTAL CONVECTION NEARS THE
AREA. THE STRONG COLD FRONT MOVES IN THURSDAY NIGHT FROM THE WEST
WITH BEST CHANCES AFTER MIDNIGHT. WILL HAVE CAT POPS SPREADING
EAST THROUGH THE NIGHT REACHING KCLE BY 12Z AND THEN CONTINUING
EAST AFTER 12Z WHILE THE WEST DRIES OUT IN STRONG SUBSIDENCE POST
FRONT. NOT CONVINCED PRECIP WILL BE OVER WEST AS WRAP AROUND
MOISTURE SPREADS BACK INTO THE AREA SO WILL MAINTAIN A CHANCE POP
FOR SHOWERS. SIGNIFICANT COOL DOWN POST FRONT WITH -11C AT 850MB OVER
THE LAKE SATURDAY MORNING. WILL LIKELY SEE LAKE EFFECT SNOW BUT AT
THIS TIME WILL NOT HAVE ACCUMS AS AIRMASS REALLY DRIES OUT AS
WELL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
FEW CHANGES IN THE EXTENDED FORECAST. MODELS CONTINUE TO MOVE HIGH
PRESSURE OFF THE NEW ENGLAND COAST ON SUNDAY ALLOWING SOUTHERLY FLOW
TO SET UP AND USHERING IN WARMER TEMPERATURES. HOWEVER WE WILL
STILL REMAIN BELOW NORMAL FOR TEMPS. GFS CONTINUES TO BE QUICKER
WITH THE NEXT SYSTEM THAN ECMWF...MOVING LOW INTO NW OHIO TUESDAY.
THE ECMWF ON THE OTHER HAND HOLDS OFF LOW UNTIL TUESDAY NIGHT. FOR
NOW WILL JUST KEEP CHANCE POPS GOING FOR NW OHIO ON TUESDAY. BEST
CHANCE FOR CONVECTION WILL BE TUESDAY NIGHT INTO WEDNESDAY.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
FRONT THAT MOVED ACROSS THE AREA MONDAY IS STALLED NEAR THE OHIO
RIVER. MODELS CONSISTENT MOVING THE FRONT NORTH AS A WARM FRONT
TONIGHT. AS THE FRONT LIFTS NORTH CIGS WILL GRADUALLY DROP TO IFR
FROM THE SOUTH OVERNIGHT. HOWEVER THINK IT WILL BE DIFFICULT FOR
IFR ALONG THE LAKESHORE WITH A SOUTHEAST FLOW SETTING UP OVERNIGHT.
BELIEVE THAT TREND IS RIGHT IN TAFS...BUT LOW CONFIDENCE ON THE
PRECISE TIMING OF THE FRONT.
CONDITIONS WILL IMPROVE TO VFR FROM THE SOUTH TOMORROW MORNING AS
THE FRONT LIFTS NORTH. HOWEVER...SOUTH-SOUTHWEST WINDS OF 20G30KT
WILL SET UP TOMORROW AFTERNOON AS LOW LEVEL JET SETS UP.
COULD SEE SOME SCATTERED SHOWERS/TSRA IN THE WEST TOMORROW
MORNING...AND ALMOST ANYWHERE TOMORROW AFTERNOON.
.OUTLOOK...NON VFR THURSDAY NIGHT AND FRIDAY IN TSRA/SHRA.
&&
.MARINE...
NORTHEAST FLOW ON THE LAKE THIS EVENING WILL SHIFT AROUND TO THE
SOUTHEAST BY MORNING AS A WARM FRONT PUSHES NORTH. A SMALL CRAFT
ADVISORY WILL BE NEEDED THURSDAY AS WINDS STEADILY INCREASE
THROUGHOUT THE DAY...HITTING/EXCEEDING THE 22 KNOT THRESHOLD.
THUNDERSTORMS WILL BE POSSIBLE JUST ABOUT ANYTIME BETWEEN NOW
THROUGH FRIDAY...BUT THE STRONG COLD FRONT WITH THIS SYSTEM WILL BE
CROSSING THE FRIDAY. THERE WILL BE SIGNIFICANT GUSTS WITH ANY
CONVECTION THURSDAY NIGHT/FRIDAY AND THEN SUSTAINED WINDS WILL
INCREASE WITH THE COLD AIR ADVECTION FROM THE WEST-SOUTHWEST FRIDAY
AFTERNOON. WINDS STILL MAY BE APPROACHING GALE FORCE FRIDAY
AFTERNOON/EVENING. CONDITIONS ON THE LAKE IMPROVE SATURDAY AS HIGH
PRESSURE MOVES OVERHEAD. SUNDAY WILL BE QUIET. THE HIGH WILL HAVE
SHIFTED EAST MONDAY...ALLOWING FOR SOUTHERLY FLOW AGAIN ON THE LAKE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...DJB
AVIATION...DJB
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
241 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS THEN EXPECTED
TO CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL BUILD OVER THE REGION AGAIN FROM THE
NORTHWEST AND REMAIN IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AT 215 PM...CONVECTION HAS BECOME MORE WIDESPREAD AS EXPECTED. COLD
POOL...OR BACKDOOR COLD FRONT IF YOU WISH WAS PUSHING S-SE OUT OF
WESTERN NC AND WILL ENTER UPSTATE SC/SOUTHERN NC PIEDMONT BY MID
AFTERNOON. SPC MESO ANAL PAGE SHOWS CAPES INCREASING TO NEAR
1000J/KG FROM FAR WESTERN NC...THROUGH NE GA/UPSTATE SC TOWARD CLT.
EXPECT NUMEROUS SHOWERS/THUNDERSTORMS WILL DEVELOP IN THIS AREA
DURING THE MID/LATE AFTERNOON TIME PERIOD. LAPSE RATES MAY BE
SUFFICENT FOR A FEW STRONG STORMS AND POSSIBLY EVEN ISOLATED SEVERE
STORMS WITH LARGE HAIL/AND OR DAMAGING WINDS. THE HRRR HAS HAD A
DECENT HANDLE ON THE CONVECTIVE TRENDS TODAY SO WILL TREND FORECAST
TOWARD ITS EXPLICIT CONVECTIVE FORECASTS WHICH PUSHES ALL OF THE
CONVECTION THROUGH THE UPSTATE BY ABOUT 00Z WITH SOME LINGERING
SHOWERS CONTINUING INTO THE EVENING NE GA/FAR WESTERN UPSTATE.
FOR THE OVERNIGHT...WILL FASHION THE FORECAST TOWARD THE DRYER 12Z
NAM/CMC REGIONAL AND 00Z ECM. GFS CONTINUES PRECIP OVERNIGHT
APPARENTLY DUE TO ISENTROPIC LIFT OVER COOL POOL ESTABLISHED BY
TODAY`S CONVECTION. WILL BANK ON THE COOL POOL BEING TOO SHALLOW FOR
ENOUGH LIFT TO PRODUCE PRECIP. HOWEVER...EXPECT THAT CLOUD COVER
WILL REMAIN WIDESPREAD OVERNIGHT. MILD TEMPS ARE STILL EXPECTED
OVERNIGHT EVEN WITH THE BACKDOOR FRONTAL PASSAGE. LOWS FROM THE
UPPER 50S TO LOWER 60S ARE FORECAST.
ON THURSDAY...THE CONSENSUS IS THAT IT WILL BE A MUCH QUIETER DAY AS
THE WESTERN ATLANTIC HIGH DOMINATES. ONLY ISOLATED AFTERNOON SHOWERS
AND THUNDRSTORMS AT BEST...AND THOSE WOULD BE MAINLY OVER THE
NORTHERN NC MOUNTAINS/FOOTHILLS. ANOTHE WARM DAY IS IN STORE WITH
HIGHSTOPPING OUT AROUND 80 OUTSIDE THE MOUNTAINS WITH MID 70S
MOUNTAIN VALLEYS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AT 230 PM EST WEDNESDAY...I WILL USE A BLEND OF THE NAM AND GFS FOR
THE PLACEMENT AND TIMING OF THE COLD FRONT. GUIDANCE CONTINUES TO
INDICATE THAT MOIST AND WEAKLY UNSTABLE RETURN FLOW SHOULD SUPPORT
UPSLOPE SHRA ACROSS THE MTNS THURSDAY EVENING INTO FRIDAY MORNING. I
WILL INDICATE SCT SHRA DEVELOPING OVER THE SE FACING MTNS AS EARLY
AS 3Z FRI...EXPANDING TO NUMEROUS SHRA BY SUNRISE FRI. THE BAND OF
SHRA/TSRA SHOULD REACH THE WESTERN NC MTNS BY 15Z...OVER THE CENTRAL
CWA BETWEEN 18-21Z...PUSHING EAST OF THE CWA BY 6Z. I WILL TIME CATE
POPS ACROSS THE CWA TO HIGHLIGHT LATEST MODEL GUIDANCE. HIGHS UNDER
THICK CLOUD COVER AND RAINFALL WILL REMAIN LIMITED...BUT EXPECTED TO
RANGE NEAR NORMAL.
NAM FORECAST SOUNDINGS ALONG AND AHEAD OF THE COLD FRONT CONTINUES
TO INDICATE WEAK INSTABILITY...GENERALLY BETWEEN 200-400 J/KG.
INSTABILITY ACROSS THE MTNS IS EVEN WEAKER. HELICITY VALUES BETWEEN
0-1 KM CONTINUE TO RANGE BETWEEN 200-250 M2/S2. EHI VALUES GENERALLY
REMAIN BELOW .5 M2/S2...HOWEVER...AREAS ACROSS THE I-77 CORRDIOR MAY
PEAK ABOVE 1 M2/S2 DURING THE MID AFTERNOON. THE LOW CAPE/HIGH SHEAR
ENVIRONMENT MAY SUPPORT WELL ORGANIZED LINES OF THUNDERSTORMS.
TIMING AND SHEAR/INSTABILITY VALUES APPEAR TO HAVE THE GREATEST
OVERLAP ACROSS THE PIEDMONT. WE WILL CONTINUE TO HIGHLIGHT THE
SEVERE POTENTIAL IN THE HWO...EMPHASIZING THE RISK FOR DAMAGING WIND
GUSTS.
THE FRONT SHOULD PUSH EAST OVER THE CWA BY LATE FRIDAY EVENING. IN
THE WAKE OF THE FRONT...A DRY AND COOL CANADIAN AIR MASS WILL SPREAD
OVER THE CENTRAL CONUS. MIN TEMPERATURES ARE FORECAST TO FALL A
COUPLE OF DEGREES BELOW NORMAL. RIDGES MAY SEE MID 30S TO NEAR
FREEZING TEMPERATURES BY 12Z SAT. COOL TEMPERATURE PROFILES WILL
REMAIN OVER THE CWA ON SATURDAY. MOS CONSENSUS INDICATES HIGH
TEMPERATURES FORECAST TO RANGE FROM THE L60S ACROSS THE MTNS TO MID
TO UPPER 60S EAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 2 PM EST WEDNESDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
SUNDAY WITH THE BROAD UPPER TROF DEAMPLIFYING AS IT LIFTS OVER NEW
ENGLAND AS HEIGHTS RISE OVER THE CAROLINAS. SOME WEAK H5 SHORTWAVE
ACTIVITY WILL PASS TO OUR NORTH ON SUNDAY AND MONDAY AS ANOTHER
LONGWAVE UPPER TROF BEGINS TO DIG DOWN OVER THE ROCKIES. THE TROF
WILL AMPLIFY EARLY NEXT WEEK AS IT APPROACHES THE FCST AREA. BY NEW
DAY 7...THE LONG RANGE MODELS INDICATE THAT THE TROF WILL BE
APPROACHING THE MISS RIVER VALLEY WITH HEIGHTS BEGINNING TO FALL
OVER THE GSP FCST AREA.
AT THE SFC...DRY AND COOL HIGH PRESSURE WILL SPREAD OVER THE REGION
ON SAT AND SUN AS LOW LVL WINDS BECOME NLY AND THEN NELY. THERE IS
SOME DISAGREEMENT WRT THE EVOLUTION OF THE SFC PATTERN ON MON AND
TUES OF NEXT WEEK. THE MODELS AGREE THAT AS THE SFC HIGH SLIDES OFF
THE NEW ENGLAND COAST THAT A WEDGE PATTERN WILL SET UP OVER THE
CAROLINAS. HOWEVER...THE ECMWF TRIES TO DEVELOP A SFC LOW...WITH SIG
WRAP AROUND MOISTURE...OFF THE CAROLINAS COAST ON TUES WHILE THE 12Z
GFS DOES NOT. EITHER WAY...THE NEXT MAJOR FRONTAL SYSTEM WILL
APPROACH THE CWFA BY THE END OF THE PERIOD ON WED AS WINDS BECOME
SELY. FOR THE TIME BEING...I HAVE USED A MORE GFS LIKE SOLUTION FOR
MON AND TUES AND ONLY HAVE A SLIGHT CHANCE POP FOR THAT TIME PERIOD.
POPS RAMP UP TO HIGH END SOLID CHANCE ON WED AS THE FRONT
APPROACHES. TEMPS ARE EXPECTED TO START OUT BELOW NORMAL OVER THE
WEEKEND AND SLOWLY CLIMB TO NEAR NORMAL BY THE END OF THE PERIOD.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...MAIN FOCUS IN THE NEAR TERM IS THUNDERSTORM THREAT AT THE
AIRFIELD. BACKDOOR COLD FRONT MOVING TOWARD THE AREA SHOULD TRIGGER
SCT/NUMEROUS SHOWERS/THUDNERSTORMS AS IT ENCOUNTERS MORE UNSTABLE
AIR VICINITY KCLT. HENCE...HAVE MAINTAINED A TEMPO FOR TSRA FROM 20
TO 22Z. SOMOE MVFR RESTRICTIONS AND GUSTY NW WINDS POSSIBLE WITH
PASSAGE OF THUDNERSTORMS. AFTER THUNDERSTORMS END...EXPECT A VFR SKY
CONDITION FOR THE OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...MAIN ISSUE IS WITH THUNDERSTORMS
THIS AFTERNNON. SHOWERS/TSRA WERE IN TEH VICINITY OF AVL/HKY AT TAF
TIME AND WILL CONTINUE A MENTION IN THE TAK UNTIL ABOUT 22Z. THE SC
AIRFIELDS WILL SEE SCT/NUMEROUS TSRA IN THE 20-23Z TIMEFRAME. EXPECT
STORMS TO DISSIPATE THIS EVENING. THE EXPECTATION IS FOR GENERALLY
VFR SKY CONDITIONS FOR THE OVERNIGHT...BUT HAVE LOWERED CIGS TO MVFR
AT KAVL AS UPSLOPE FLOW DEVELOPS LATE TONIGHT.
OUTLOOK...VFR CONDTIONS ARE EXPECTED FROM THU AFTERNOON THROUGH THU
NIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH
THUNDERSTORMS AND ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES
WILL RETURN OVER THE WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 95% HIGH 95% HIGH 96% HIGH 96%
KGSP HIGH 91% HIGH 95% MED 77% HIGH 98%
KAVL HIGH 95% HIGH 100% HIGH 81% HIGH 90%
KHKY HIGH 100% HIGH 95% HIGH 97% HIGH 95%
KGMU HIGH 91% HIGH 95% MED 77% HIGH 98%
KAND HIGH 100% HIGH 91% MED 79% HIGH 96%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...LG
SHORT TERM...NED
LONG TERM...JPT
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
142 PM EDT WED APR 17 2013
.SYNOPSIS...
HIGH PRESSURE WILL WEAKEN OVER THE AREA AND MOVE EAST BRINGING A
MOIST SOUTHERLY FLOW THROUGH THURSDAY. A COLD FRONT IS EXPECTED TO
CROSS THE REGION ON FRIDAY AND REACH THE ATLANTIC COAST BY EARLY
SATURDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH AND REMAIN
IN PLACE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 125 PM...SHOWERS/THUNDERSTORMS INCREASING IN COVERAGE AS
BACKDOOR COLD FRONT/COLD POOL MOVES INTO WESTERN NC. CURRENT
FORECAST ESSENTIALLY ON TRACK WITH POPS...BUT MAY HAVE TO MAKE SOME
ADJUSTMENTS TO TEMPS WHERE PRECIP OCCURRING. ATMOSPHERE
DESTABALIZING OVER THE PIEDMONT PER SPC MESOANAL PAGE...SO HRRR IDEA
OF BRING CONVECTION INTO THE PIEDMONT MID/LATE AFTERNOON LOOKS VERY
REASONABLE.
PREVIOUS DISCUSSION:
AS OF 915AM...CURRENT REGIONAL RADARS SHOW A CLUSTER OF SHOWERS/STORMS
OVER NE TN/SW VA AND SE KY MOVING SE. THIS MOVEMENT WILL BRING AT
LEAST SCT SHOWERS/THUNDERSTORMS INTO THE NORTHERN MOUNTAINS THIS
MORNING. THE LATEST HRRR SHOWS NUMEROUS SHOWERS/THUNDERSTORMS
DEVELOPING OVER THE MOUNTAINS AROUND MIDDAY APPARENTLY ACTIONG ON
THE OUTFLOW BOUNDARY FROM THE EARLY MORNING CONVECTION. THE HRRR
THEN MOVES THE CONVECTION INTO THE PIEDMONT BY LATE AFTERNOON. THE
06Z NAM SUPPORTS THIS GENERAL IDEA AS WELL. HENCE...HAVE UPPED POPS
INTO THE NUMEROUS RANGE FOR MOST OF THE MOUNTAINS TODAY WITH
SCATTERED COVERAGE OVER THE PIEDMONT AREAS...EXCEPT ISOLD THE
SOUTHERN UPSTATE. ALSO UPDATED TEMP/DEWPOINT/WIND TRENDS FOR THE
MORNING.
AS OF 7 AM...LINE OF CONVECTION MOVED INTO THE NC MTNS AND BECAME AN
AREA OF SHRA. EXPECT THE SHRA TO MOVE ACROSS THE NRN TIER...AND
POSSIBLY INTO THE SRN NC FOOTHILLS AND PIEDMONT BEFORE DISSIPATING
BY MID MORNING. STILL LOOKS LIKE AT LEAST SCT COVERAGE REDEVELOPS
DURING THE AFTERNOON IN INCREASING INSTABILITY. WE MAY END UP WITH
SCT COVERAGE OVER NE GA/UPSTATE...ESPECIALLY IF AN OUTFLOW BOUNDARY
FROM THE MORNING CONVECTION MOVES THRU. HOWEVER...NOT CONFIDENT ENUF
OT UP POP ATTM.
PREVIOUS DISCUSSION...REGIONAL RADAR CONTINUES TO SHOW MCS
CONVECTION MOVING TOWARD THE AREA FROM NE TN/SW VA. THERE IS A SLY
TRAJECTORY TO THE CONVECTION AND CORFIDI VECTORS INDICATE THE
CONVECTION COULD SLIDE INTO THE NRN MTNS AND FOOTHILLS. HAVE GONE
WITH SCT CONVECTION MOVING INTO THAT AREA...BUT DISSIPATING BEFORE
MOVING OUT OF THE BLUE RIDGE. THE TRAJECTORY OF THE CONVECTION
BEHIND THE INITIAL MCS IS CURRENTLY ENE. THEREFORE...DISSIPATE THE
INITIAL CONVECTION AFTER DAYBREAK... BEFORE DEVELOPING CONVECTION
OVER THE AREA AGAIN DURING THE AFTERNOON AS INSTABILITY DEVELOPS.
THE GUIDANCE IS NOW INDICATING INSTABILITY ACROSS THE NC FOOTHILLS
AND PIEDMONT AS WELL AS THE MTNS. THEREFORE...HAVE UPPED COVERAGE TO
SCT FOR ALL OF NC. KEPT CONVECTION ISOLATED OVER SC AS THERE IS
INSTABILITY THERE...BUT LESS IN THE WAY OF LOW LEVEL FORCING FOR
INCREASED COVERAGE. CANNOT RULE OUT ISOLATED SVR STORMS...MAINLY
ACROSS THE MTNS...WITH LOW WET BULB ZERO LEVELS AND SOME DCAPE
DEVELOPING. HIGHS LOOK TO BE A TAD COOLER THAN PREV FCST...BUT STILL
ABOUT 10 DEGREES ABOVE NORMAL.
CONVECTION WILL LINGER INTO THE EARLY EVENING...BUT DISSIPATE DURING
THE LATE EVENING WITH LOSS OF HEATING. LOW LEVEL SELY FLOW DEVELOPS
OVERNIGHT. WITH CONTINUED COPIOUS LOW LEVEL MOISTURE...EXPECT
ISOLATED SHOWERS TO LINGER ALONG THE BLUE RIDGE EVEN AFTER MIDNIGHT.
THIS WILL ALSO LEAD TO CONTINUED CLOUDINESS. LOWS SHUD BE 10 TO 15
DEGREES ABOVE NORMAL.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AT 230 AM EST WEDNESDAY...AN UPPER RIDGE WIL BE OFF THE EAST COAST
ON THURSDAY...WITH A TROUGH OVER THE PLAINS. BY FRIDAY MORNING...
THE TROUGH WILL BE OVER THE MS RIVER VALLEY. ON FRIDAY NIGHT THE
TROUGH WILL START TO DEAMPLIFY OVER THE CENTRAL AND SOUTHERN
APPALACHIANS.
A MOIST SOUTHEASTERLY FLOW WILL BE OVER GA AND THE CAROLINAS ON
THURSDAY IN ADVANCE OF A COLD FRONT MOVING INTO THE MS RIVER VALLEY.
THE MODELS SHOW RATHER LIMITED INSTABILITY DURING THE DAY...MAINLY
OVER THE MOUNTAINS AND THE PIEDMONT. AS THE FRONT CROSSES THE TN
RIVER VALLEY FRIDAY NIGHT...MOIST INFLOW INCREASES WITH A TIGHTENING
PRESSURE GRADIENT...SUPPORTING INCREASING POPS. INSTABILITY WILL
WANE IN THE EVENING..THEN INCREASE TOWARD DAYBREAK IN THE
MOUNTAINS...COINCIDING WITH MODERATE SHEAR. BY MIDDAY FRIDAY THE
FRONT WILL BE ALONG THE INTERSTATE 85 CORRIDOR...BY WHICH TIME THE
MODEL SHOW THE BEST INSTABILITY OUT AHEAD OF THE BEST HELICITY...
ALTHOUGH ENOUGH OVERLAP IS PRESENT TO BE OF CONCERN. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT UNTIL FRIDAY...WHEN CLOUDS
AND PRECIPITATION WILL HOLD MAXIMUMS TO AROUND NORMAL.
THE FRONT WILL MOVE EAST OF OUR AREA SATURDAY EVENING...WITH A DRIER
AND COOLER AIR MASS MOVING IN FROM THE WEST OVERNIGHT. ALTHOUGH
MINIMUM TEMPERATURES WILL BE IN THE MID 30S AT HIGHER ELEVATIONS OF
THE NC MOUNTAINS... THE DRIER AIR COMBINED WITH POST FRONTAL WINDS
SHOULD PREVENT FROST FROM FORMING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AT 230 AM EST WEDNESDAY...THE EASTERN TROUGH WILL CONTINUE TO
DEAMPLIFY OVER THE WEEKEND...WHILE ANOTHER TROUGH SLOWLY AMPLIFIES
OVER THE PLAINS. THE RESULT WILL BE A NEARLY ZONAL FLOW OVER THE
EASTERN TWO THIRDS OF THE NATION. BY MONDAY THE PATTERN AMPLIFIES...
WITH AN EAST COAST RIDGE AND CENTRAL USA TROUGH. ON TUESDAY THE
TROUGH MOVES OFF THE EAST COAST...AND THE RIDGE UPSTREAM REACHES THE
MS RIVER VALLEY.
SATURDAY AND SUNDAY FEATURE DRY HIGH PRESSURE MOVING ACROSS THE
APPALACHIANS. BY MONDAY THIS SURFACE HIGH WILL EXTEND ALONG THE
EASTERN SEABOARD...WHILE THE OLD SURFACE FRONT WILL BE STALED NEAR
THE GULF COAST. ISENTROPIC UPGLIDE OVER THIS BOUNDARY WILL SPREAD
CLOUDS AND PRECIPITATION NORTH ACROSS OUR AREA. THE SURFACE RIDGE
WEAKENS ON TUESDAY...WHILE ANOTHER COLD FRONT WILL MOVE INTO THE TN
RIVER VALLEY FORM THE WEST. MAXIMUM TEMPERATURES WILL RUN AROUND SIX
OR SEVEN DEGREES BELOW NORMAL FROM SATURDAY THROUGH TUESDAY....WHILE
MINIMUM TEMPERATURES RUN AROUND NORMAL.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...MAIN FOCUS IN THE NEAR TERM IS THUNDERSTORM THREAT AT THE
AIRFIELD. BACKDOOR COLD FRONT MOVING TOWARD THE AREA SHOULD TRIGGER
SCT/NUMEROUS SHOWERS/THUDNERSTORMS AS IT ENCOUNTERS MORE UNSTABLE
AIR VICINITY KCLT. HENCE...HAVE MAINTAINED A TEMPO FOR TSRA FROM 20
TO 22Z. SOMOE MVFR RESTRICTIONS AND GUSTY NW WINDS POSSIBLE WITH
PASSAGE OF THUDNERSTORMS. AFTER THUNDERSTORMS END...EXPECT A VFR SKY
CONDITION FOR THE OVERNIGHT.
ELSEWHERE...JUST LIKE AT KCLT...MAIN ISSUE IS WITH THUNDERSTORMS
THIS AFTERNNON. SHOWERS/TSRA WERE IN TEH VICINITY OF AVL/HKY AT TAF
TIME AND WILL CONTINUE A MENTION IN THE TAK UNTIL ABOUT 22Z. THE SC
AIRFIELDS WILL SEE SCT/NUMEROUS TSRA IN THE 20-23Z TIMEFRAME. EXPECT
STORMS TO DISSIPATE THIS EVENING. THE EXPECTATION IS FOR GENERALLY
VFR SKY CONDITIONS FOR THE OVERNIGHT...BUT HAVE LOWERED CIGS TO MVFR
AT KAVL AS UPSLOPE FLOW DEVELOPS LATE TONIGHT.
OUTLOOK...VFR CONDTIONS ARE EXPECTED FROM THU AFTERNOON THROUGH THU
NIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION FRI...WITH
THUNDERSTORMS AND ASSOCIATED RESTRICTIONS POSSIBLE. DRY HIGH PRES
WILL RETURN OVER THE WEEKEND.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-17Z
KCLT HIGH 100% HIGH 100% HIGH 96% HIGH 90%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KAVL HIGH 100% HIGH 100% HIGH 94% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 96% MED 65%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 90%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 87%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...LG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1244 PM CDT WED APR 17 2013
.UPDATE...
ISSUED AT 1042 AM CDT WED APR 17 2013
MADE A BIT OF A MODIFICATION TO THE WINTER WEATHER ADVISORY IN
THAT WE POSTPONED THE START OF THE ADVISORY FOR MUCH OF OUR
WESTERN ZONES UNTIL 00Z THIS EVENING. WE DID KEEP IT AS IS FOR
GREGORY AND BRULE COUNTIES...PRIMARILY FOR THE THREAT OF LIGHT
FREEZING DRIZZLE. WINNER CONTINUES TO REPORT SOME SORT OF LIGHT
MIXED PRECIPITATION...AND TEMPERATURES SO FAR IN SOUTH CENTRAL SD
ARE BELOW FREEZING. THAT SAID...CHAMBERLAIN AND SURROUNDING
VICINITY MAY WARM UP TO JUST ABOVE FREEZING THIS AFTERNOON. BUT
SOME EXISTING SNOW COVER IN THOSE AREAS...THE ACTUAL GROUND
TEMPERATURE MAY BE A BIT COOLER ALLOWING ANY DRIZZLE TO PARTIALLY
FREEZE ON CONTACT.
OTHERWISE...THE WARM AIR ADVECTION WHICH HELPED TO CAUSE THE
PRECIPITATION THIS MORNING IN NORTHWEST IOWA IS EXITING AT THIS
TIME. THEREFORE A BULK OF OUR FORECAST AREA IS LEFT WITH MOISTURE
STARVED MID LEVELS...SEEN BEST ON THE RAP SOUNDINGS. THERE IS SNOW
TO THE WEST OF OUR FORECAST AREA WHERE 650MB FRONTOGENESIS IS
MAXIMIZED AND WHERE THERE IS MID LEVEL MOISTURE. HOWEVER IN OUR
FORECAST AREA...THE MAXIMIZED FRONTOGENESIS IS LOWER...AROUND
750MB TO 700MB...AND CONDITIONS ARE QUITE DRY IN THAT LAYER
THROUGH MUCH OF THE AFTERNOON. IN FACT IN OUR SOUTHEAST ZONES...
THE FRONTOGENESIS WAS IN THE LOWER LEVELS EARLIER TODAY...AND THAT
TOO IS TEMPORARILY WANING. SO THINKING OF LOWERING POPS IN MANY
AREAS UNTIL 21Z AND INCLUDE DRIZZLE...THEN BEGIN TO RAMP UP THE
POPS AGAIN LATE THIS AFTERNOON AS THE NEXT WELL ADVERTISED STRONG
WAVE APPROACHES.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CDT WED APR 17 2013
COMPLEX SET UP THIS MORNING WITH A COUPLE OF AREAS OF PRECIPITATION.
THE FIRST WAS A SNOW BAND THAT WAS VERY SLOWLY WORKING EAST INTO THE
FAR WESTERN CWA THIS MORNING. THE SOUTH AND EAST EDGE OF THIS BAND
HAS REALLY STRUGGLED TO DEVELOP BUT SOME HINTS THAT THERE WILL BE
SOME DEVELOPMENT THROUGH THE MORNING INTO THE WESTERN CWA. THE
SECOND AREA WAS ASSOCIATED WITH A POTENT AREA OF THETA E ADVECTION
AND MODERATE INSTABILITY ACROSS KANSAS. EXPECT THIS AREA TO
CONTINUE TO DEVELOP NORTHEAST THROUGH THE EARLY MORNING HOURS AND
CLIP THE SOUTHEAST THIRD OF THE CWA. WILL HAVE THUNDER OVER PARTS OF
NORTHWEST IOWA WITH DECENT ELEVATED INSTABILITY BUT NOT THINKING
SEVERE. INCREASED QPF AMOUNTS A BIT IN THESE AREAS AS WELL TO AROUND
A QUARTER TO THREE QUARTERS OF AN INCH THIS MORNING. IN BETWEEN
THESE TWO AREAS OVER EAST CENTRAL SOUTH DAKOTA AND SOUTHWEST
MINNESOTA THE POTENTIAL FOR NOT TOO MUCH ACTIVITY AS THE BAND OF
SNOW LOCKS UP TOT HE EAST TODAY AND THE CONVECTIVE ELEMENTS REMAIN
MAINLY SOUTH AND EAST. HOWEVER...ONCE THE UPPER LEVEL SUPPORT MOVES
INTO NEBRASKA TONIGHT EXPECT THIS RELATIVE BLANK SPOT TO FILL IN
QUICKLY THIS EVENING. SUSPECT MAINLY RAIN IN THE EASTERN CWA WHILE
THE WEST WILL BE MAINLY SNOW.
TONIGHT INTO THURSDAY POSES A PROBLEM FOR THE AREA WITH
FAIRLY GOOD AGREEMENT AMONGST THE VARIOUS MODELS DYNAMICALLY. THEY
ALL AGREE IN SWINGING THE STRONGEST PV ADVECTION NORTHWARD LATE
WEDNESDAY NIGHT INTO SOUTHEAST SOUTH DAKOTA THEN SHIFT IT EAST
GRADUALLY THROUGH THE DAY THURSDAY. IN FACT MEASURABLE SNOWFALL IS
PRETTY LIKELY IN THE EASTERN CWA THURSDAY EVENING. IT APPEARS THAT
THERE WILL BE A VERY STRONG MID LEVEL BOUNDARY IN PLACE WHICH WILL
COME NORTH THIS MORNING WITH THE STRONG LOW AND MID LEVEL THETA E
ADVECTION. THIS WAVE WILL BE ABLE TO INTERACT WITH THIS THERMAL
BOUNDARY AND IF THE SOUNDINGS ARE CORRECT SOMETHING CLOSE TO THE
750MB FRONT WILL YIELD THE MOST POTENT PRECIPITATION RATES AS A
PARCEL LIFTED FROM THIS LEVEL WOULD HAVE ABOUT 150 TO 300 J/KG
UNCAPPED CAPE TO WORK WITH. THERE MAY BE A SMALL RIBBON OF SLEET OR
FREEZING RAIN FROM ABOUT 22Z THROUGH 5Z BUT THIS LOOKS TO BE MORE OF
A TRANSITIONAL ISSUE VERSUS LAST WEEKS SUSTAINED PERIOD OF SLEET AND
FREEZING RAIN. SO FOR NOW NOT PLANNING ON ANY MAJOR ICE PROBLEMS AND
ONLY A BRIEF PERIOD FOR 1 TO 2 HOURS FROM ABOUT INTERSTATE 29 EAST
VERY LATE THIS AFTERNOON AND THIS EVENING. FAIRLY CONSISTENT SIGNALS
FROM THE MODELS THAT FROM ABOUT 0Z THURSDAY THROUGH 0Z FRIDAY A HALF
TO THREE QUARTERS OF AN INCH OF LIQUID WILL BE LIKELY AND MOST OF
THIS WILL FALL AS SNOW...AGAIN POSSIBLY A LITTLE SLEET TO START.
SUSPECT SNOWFALL RATIOS WILL BE LIMITED AND WILL AIM FOR AN AVERAGE
OF ABOUT 9:1 THROUGH THE EVENT...ALTHOUGH SOMETHING CLOSE TO 12:1
WILL BE POSSIBLE THURSDAY AFTERNOON. WILL ISSUE AN ADVISORY FOR
SOUTHWEST MINNESOTA INTO SOUTHEAST SOUTH DAKOTA FOR THE EXPECTED
SNOW TONIGHT INTO THURSDAY. BORDERLINE WARNING CRITERIA BUT WITH A
WET SNOW AND MELTING/COMPACTION POTENTIAL WILL LEAN TOWARDS A HIGH
END ADVISORY.
THE SNOW SHOULD WIND DOWN THURSDAY NIGHT WITH FRIDAY JUST LOOKING
WINDY AND COLD. TEMPERATURES FROM TODAY INTO FRIDAY SHOULD BE ABOUT
20 TO 25 DEGREES BELOW NORMAL.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 329 AM CDT WED APR 17 2013
THIS WEEKEND INTO EARLY NEXT WEEK SHOULD SEE CONTINUED BELOW NORMAL
TEMPERATURES WITH TROUGHING REMAINING OVER THE CENTRAL US. WAVE
MOVING THROUGH SATURDAY NIGHT INTO SUNDAY SHOULD BRING AT LEAST
SCATTERED SHOWERS TO THE AREA...THERMAL PROFILES LOOK WARM ENOUGH FOR
ANY PRECIP TO BE RAIN WITH THIS WAVE. HIGHS SATURDAY SHOULD MAINLY
BE IN THE 40S...COULD SEE SOME 50S ON SUNDAY AHEAD OF THE
APPROACHING COLD FRONT. THE FRONT PUSHES THROUGH SUNDAY NIGHT INTO
MONDAY RESULTING IN HIGHS BACK INTO THE 40S FOR EARLY NEXT WEEK.
RAIN SHOWER CHANCES CONTINUE SUNDAY NIGHT INTO MONDAY WITH THIS
FRONTAL PASSAGE AND DIGGING WAVE. THERMAL PROFILES SUGGEST BY LATER
MONDAY ANYTHING THAT FALLS COULD BE SNOW. HOWEVER MODELS DIFFER ON
THEIR HANDLING OF THE DIGGING WAVE...WITH THE LATEST 0Z ECMWF THE
MOST AGGRESSIVE WITH THE SYSTEM...CUTTING THE LOW OFF TO OUR SOUTH AND
GIVING PORTIONS OF OUR CWA SNOW OR RAIN ON TUESDAY. THIS IS AN
OUTLIER SOLUTION AT THIS TIME...WITH THE MORE LIKELY RESULT BEING A
MORE PROGRESSIVE WAVE AND JUST LIGHTER QPF AMOUNTS SUNDAY NIGHT INTO
MONDAY NIGHT. HOWEVER WILL HAVE TO CONTINUE TO MONITOR TRENDS ON
THIS SYSTEM. FURTHER IN THE EXTENDED...FINALLY SOME DECENT SIGNS IN
THE LONG TERM ENSEMBLES THAT WE SEE TEMPERATURES WARMING TO AT OR
ABOVE NORMAL BY AROUND THE LAST WEEKEND OF THE MONTH. OF COURSE THIS
IS STILL FAR OUT...BUT MAYBE A SIGN THAT SPRING WILL FINALLY ARRIVE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1244 PM CDT WED APR 17 2013
STILL SEEING SOME VFR CONDITIONS NORTH OF I-90 AT THE START OF THE
PERIOD. HOWEVER...DETERIORATING CONDITIONS SPREADING NORTH ACROSS THE
AREA FROM NEBRASKA...WITH MVFR-IFR CEILINGS/VISIBILITY IN -DZ/BR
EXPECTED TO BE THE NORM THROUGHOUT THE AREA BY 21Z. IFR-LIFR CEILINGS
ALONG WITH IFR VISIBILITY THEN EXPECTED TO DOMINATE FOR THE REMAINDER
OF THE TAF PERIOD. PRECIPITATION TYPE WILL VARY FROM -DZ TO -SN...
DEPENDENT UPON MID LEVEL MOISTURE. CURRENT MODELS SHOWING -DZ MORE
LIKELY THROUGH THE EVENING...WITH -SN BECOMING MORE LIKELY AFTER
18/06Z. SNOW COULD BECOME MODERATE AT TIMES THROUGH CENTRAL PORTIONS
OF THE FORECAST AREA...INCLUDING AT KFSD...DURING THE LATTER HALF OF
THE TAF PERIOD...RESULTING IN MORE WIDESPREAD LIFR VISIBILITY WITH
PERIODS OF VLIFR VISIBILITY POSSIBLE. INCREASING NORTHERLY WINDS WILL
COMPOUND VISIBILITY ISSUES DURING THE LATTER HALF OF THE TAF PERIOD
AS WINDS GUSTING OVER 25KTS PRODUCE AREAS OF BLOWING SNOW ALONG WITH
THE FALLING SNOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR SDZ038>040-052>056-058>071.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT FRIDAY FOR SDZ050-057.
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR MNZ071-072-080-081-089-090-097-098.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR IAZ001-002-012-020.
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM CDT
FRIDAY FOR NEZ013.
&&
$$
UPDATE...MJF
SHORT TERM...08
LONG TERM...CHENARD
AVIATION...JH
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
426 PM CDT WED APR 17 2013
.MESOSCALE UPDATE...SEVERE THUNDERSTORM WATCH CONTINUES UNTIL 9 PM.
ONGOING CONVECTION OVER EASTERN COUNTIES BEING MONITORED FOR
POSSIBLE INTENSIFICATION AT THIS TIME OF MAX HEATING, AND
SATELLITE PICS SHOW GUST FRONT MOVING WESTWARD TOWARD THE I-65
CORRIDOR IS ASSOCIATED WITH A BAND OF MODERATE CU. DOPPLER
INDICATES GUSTS OF 25 TO 30 MPH WILL OCCUR WITH THE PASSAGE OF THE
GUST FRONT FRONT AND ASSOCIATED BAND OF CU WILL ALSO HAVE TO BE
MONITORED FOR THUNDERSTORM DEVELOPMENT AS IT PUSHES THROUGH AN
UNSTABLE AIR MASS (WHERE RUC SOUNDINGS SHOW LI`S AROUND -6 AND
CAPES OF 2500 J/KG).
ONE CAVEAT IS THAT LATEST RUC SHOWS UPPER LEVEL SUBSIDENCE MAY BE
WORKING AGAINST DEVELOPMENT OVER WESTERN PARTS OF THE WATCH AREA
THIS AFTERNOON. HOWEVER, STILL CAN`T RULE OUT SOME ISOLATED
CONVECTION POPPING UP IN THE AFTERNOON HEAT.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
19
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1257 PM CDT WED APR 17 2013
.AVIATION...
BREEZY SW WINDS AT KLBB WILL CONTINUE THROUGH EARLY EVENING WITH SOME
MINOR VSBY RESTRICTIONS DUE TO BLDU. A COLD FRONT WILL MOVE
THROUGH OVERNIGHT WITH BRISK NORTH WINDS CONTINUING THROUGH
THURSDAY MORNING. AT KCDS...LOW CEILINGS MAY BREAK OUT FOR A
PERIOD IN THE AFTERNOON BUT CONFIDENCE IS LOW. THERE IS ALSO
UNCERTAINTY IN THE WIND DIRECTION AND THUNDERSTORM ACTIVITY IS EXPECTED
IN THE VICINITY. THE COLD FRONT WILL MOVE THOUGH AROUND 05-06Z AND
SKY CONDITIONS SHOULD IMPROVE THURSDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 1145 AM CDT WED APR 17 2013/
UPDATE...
THE CONVECTIVE FORECAST FOR THIS AFTERNOON AND EVENING IS TRICKY AS
IT HINGES ON THE COMPLEX INTERPLAY OF STRONG DYNAMICS ALOFT AND
SEVERAL MORE MESOSCALE-TYPE FEATURES AT THE SURFACE. AT 11 AM...A
SURFACE LOW WAS DEEPENING ACROSS ERN NM WITH A DRYLINE FORMING UP
ALONG THE NM/TX STATE LINE. FARTHER EAST...COOL...AND MOIST AIR
REMAINED BANKED UP AGAINST THE CAPROCK WITH A WARM FRONT NOSING
NORTHWARD INTO STONEWALL COUNTY. THIS IS CREATING QUITE A WIDE
RANGE OF SENSIBLE WX CONDITIONS ACROSS THE AREA LATE THIS MORNING.
MUCH OF THE MORNING MODEL GUIDANCE DO NOT HANDLE THE POSITION OF
THE SURFACE FEATURES WELL WHICH LOWERS CONFIDENCE IN THEIR
AFTERNOON PROJECTIONS.
THE GENERAL TREND OF THE FORECAST REMAINS INTACT THOUGH AS THE
DRYLINE SHOULD MIX ACROSS MOST OF THE CAPROCK. HOWEVER...THE
DRYLINE WILL ENCOUNTER MORE RESISTANCE ACROSS THE NORTH...NAMELY
SWISHER...BRISCOE AND FLOYD COUNTIES WHERE COOL UPSLOPE FLOW IS
PERSISTENT. THE 15Z RAP NEVER ERODES THIS COOL WEDGE AND INSTEAD
IT SERVES AS A BOUNDARY TO INITIATE CONVECTION AROUND 20 UTC.
OTHER GUIDANCE STILL TAKES THE DRYLINE FARTHER EAST...ALTHOUGH
PERHAPS NOT QUITE AS FAR AS PREVIOUSLY INDICATED. ANOTHER CONCERN
IS TEMPERATURES AND PROGRESS OF THE WARM SECTOR. WHILE THERE
SHOULD BE PLENTY OF CONDITIONAL INSTABILITY /SBCAPES IN EXCESS OF
2000 J/KG ACROSS THE ROLLING PLAINS...IT IS POSSIBLE THAT CLOUD
COVER AND COOLER TEMPS MAY HELP KEEP OUR NE ZONES CAPPED. WHILE IT
APPEARS THAT THE MOST LIKELY SCENARIO IS THAT T-STORM DEVELOPMENT WILL
BE FAVORED FROM ERN PORTIONS OF COTTLE AND KING COUNTIES NEWD TO
THE RED RIVER VALLEY WHERE THE DRYLINE/FRONT TRIPLE POINT IS
EXPECTED TO BE LOCATED...WE HAVE GONE AHEAD AND PULLED POPS BACK
WEST ACROSS THE FAR SRN PANHANDLE AND NRN ROLLING PLAINS IN CASE
1. THE DRYLINE HANGS UP FARTHER WEST IN THAT AREA...AND 2. THE CAP
CAN BREAK DESPITE THE COOLER TEMPS. CAPE AND SHEAR SHOULD BE MORE
THAN ADEQUATE FOR SUPERCELLS AND A THREAT OF HAIL/DAMAGING WINDS
AND ISOLATED TORNADOES...ESPECIALLY ALONG THE REMNANT FRONTAL
BOUNDARY...WHICH COULD BE PRESENT IN THE ERN ROLLING PLAINS.
PREV DISCUSSION... /ISSUED 658 AM CDT WED APR 17 2013/
AVIATION...
WE ARE STARTING OUT WITH AN LIFR CIG AND VSBY AT KCDS AND UNSETTLED
IFR TO MVFR CONDITIONS AT KLBB. TIMING THE IMPROVEMENT OF THESE
CONDITIONS WILL BE TRICKY...THOUGH KLBB WILL CERTAINLY IMPROVE
RAPIDLY BY MID MORNING OR SO...PERHAPS AN HOUR EARLIER OR LATER
THAN STATED IN THE TAF. VSBY AT KLBB LIKELY TO DETERIORATE HOWEVER
BY LATER IN THE AFTERNOON AS STRONG SOUTHWEST WINDS SHOULD BE ABLE
TO KICK BLOWING DUST INTO THE AIR WITH POSSIBLE MVFR VSBY ONCE
AGAIN. THERE IS GREATER UNCERTAINTY IN TIMING IMPROVEMENT AT KCDS
AS SOME SOLUTIONS INDICATE VERY LITTLE TO NO IMPROVEMENT WHILE
OTHERS INDICATE LOW CLOUDS COMPLETELY CLEARING OUT BY MID
AFTERNOON. WE HAVE KCDS PLAYED IN-BETWEEN THESE TWO CAMPS. A
STRONG COLD FRONT WILL ARRIVE DURING THE EVENING...EARLY AT KCDS
AND NEARER MIDNIGHT OR 06Z AT KLBB. THIS FRONT MAY PROVE A FOCUS
FOR SEVERE WEATHER MAINLY NEAR OR JUST EAST OF KCDS LATER TODAY SO
AVIATION USING THAT TERMINAL SHOULD PAY CONSIDERABLE ATTENTION TO
TAF UPDATES AND RADAR TRENDS. AN MVFR LAYER SEEMS MOST LIKELY AT
KCDS AGAIN TOWARDS THE END OF THIS FORECAST FOLLOWING THE
FRONT...AND LIKELY WILL OCCUR JUST BEYOND THIS FORECAST AT KLBB AS
WELL. RMCQUEEN
PREV DISCUSSION... /ISSUED 447 AM CDT WED APR 17 2013/
SHORT TERM...
LOW LEVEL MOISTURE WAS EDGING BACK WEST VIA ANOTHER WEAKENING AND
SHALLOW FRONTAL SLOSH THROUGH NORTHERN AND EASTERN ZONES AND
SOUTHEAST COMPONENT RETURNING MOISTURE ONTO THE CAPROCK. LIFT WAS
OCCURRING ALONG THE WESTERN BORDER WITH A WAVE LIFTING NORTHEAST
ACROSS THE AREA...BUT ONLY RESULTING IN MARGINAL ENHANCEMENT OF MID
AND HIGH CLOUDS. THUNDER WAS DEVELOPING MUCH FURTHER UPSTREAM OVER
THE CENTRAL PLAINS FROM THIS WAVE AS OUR AIRMASS REMAINED
CONSTRAINED BY A SOLID CAP NEAR THE 800 MB LEVEL. LOW CLOUDS SHOULD
EVENTUALLY EXPAND OVER MOST OF THE CENTRAL AND EASTERN AREAS BY
EARLY WEDNESDAY AND ALONG WITH LIGHT SHOWER OR DRIZZLE CHANCES
SHOULD BE THE DOMINANT WEATHER FOR THE MORNING. WE ALSO WILL SEE THE
LOW CLOUDS ERODE QUICKLY BY MID TO LATE MORNING ON THE CAPROCK WITH
DEEPER MIXING INTO THE STRONGER SOUTHWEST COMPONENTS ALOFT.
BY AFTERNOON THE DRY GUSTY SOUTHWEST WINDS SHOULD BE THE PRIMARY
WEATHER WITH MOISTURE CONTINUING TO ERODE SLOWLY THROUGH PARTS OF
THE ROLLING PLAINS AS WELL. CONSIDERABLE DISAGREEMENT REMAINS
BETWEEN MODEL CAMPS HOWEVER REGARDING NORTHWARD AND WESTWARD EXTENT
OF MIXED AIRMASS THROUGH THE ROLLING PLAINS. WE TEND TO LEAN TOWARDS
A MORE BACKED LOW LEVEL COMPONENT YET ARE NOT CONVINCED THAT AT
LEAST SOME PERIOD OF DEEP MIXING COULD ALSO WORK AS FAR NORTH AND
EAST AS CHILDRESS. A CONDITIONAL MENTION OF THUNDER AND SEVERE
STORMS WILL DEVELOP FROM THE FRONT AND DRY-LINE INTERSECTION
SOUTHWARD THROUGH EASTERN PORTIONS OF THE ROLLING PLAINS
ESPECIALLY...WHICH IS CONSISTENT WITH PREVIOUS FORECAST.
THUNDER CHANCES SHOULD INCREASE WITH ARRIVAL OF A STRONGER COLD
FRONT THIS EVENING THAT COULD FINALLY ALLOW CONVECTION TO DEEPEN AND
REALIZE THE CONSIDERABLE BUOYANT AND SHEARED ENVIRONMENT. THE SLOWLY
ERODING AND LIFTING CAP MAY STILL OFFER SOME RESISTANCE...HOWEVER...
THUS LIMITING CONFIDENCE FURTHER SOUTH THROUGH THE ROLLING PLAINS.
COLD FRONT WILL SURGE SOUTHWARD OVERNIGHT SPREADING LOW CLOUDS ONCE
MORE ACROSS MUCH OF THE AREA. WINDS MAY BECOME CLOSE TO WIND
ADVISORY LEVELS. PRECIPITATION CHANCES BEHIND THE FRONT APPEAR
SMALL...THOUGH WE RETAINED MINIMAL DRIZZLE MENTION NORTHERN ZONES
INCLUDING FREEZING DRIZZLE WITH TEMPERATURES EXPECTED TO DROP A
LITTLE BELOW FREEZING LATER TONIGHT ACROSS THE SOUTHWEST PANHANDLE
COUNTIES. RMCQUEEN
LONG TERM...
THURSDAY MORNING WILL START OFF BRISK ACROSS THE FAR SOUTHERN TEXAS
PANHANDLE...SOUTH PLAINS...AND ROLLING PLAINS BEHIND A STRONG COLD
FRONT EXHIBITING ABRUPT PRESSURE RISES. DO NOT BELIEVE WIND ADVISORY
CRITERIA WILL BE MET FOR AN EXTENDED PERIOD GIVEN AN OVERNIGHT
FRONTAL PASSAGE AND H70 200 NAUTICAL MILE HEIGHT GRADIENTS
SUPPORTING WINDS TOPPING OUT NEAR THE LOW END THRESHOLD OF 30 MPH.
SKIES SHOULD QUICKLY CLEAR AS DRIER AIR FILTERS IN ALONG WITH STOUT
COLD AIR ADVECTION ONLY ALLOWING HIGH TEMPERATURES TO REACH THE
UPPER 40S NORTHWEST TO MID-UPPER 50S SOUTHEAST. WINDS WILL DECREASE
THROUGH THE AFTERNOON AS JET MAX ALOFT PUSHES EAST AND PRESSURE
GRADIENT WEAKENS AHEAD OF APPROACHING SURFACE RIDGE FROM THE
ROCKIES. WHILE PORTIONS OF THE CAPROCK NORTH AND WEST OF LUBBOCK MAY
SEE FREEZING TEMPERATURES THURSDAY MORNING...A WIDESPREAD AND MUCH
HARDER FREEZE WILL TAKE PLACE FRIDAY MORNING AS CLEAR SKIES...LIGHT
WINDS...AND DRY CONDITIONS PROMOTE STRONG RADIATIONAL COOLING WITH
SURFACE RIDGING EXTENDING ACROSS THE AREA. NORTHWEST ZONES WILL
LIKELY BOTTOM OUT IN THE MID 20S WHILE UPPER 20S TO LOW 30S OCCUR
ELSEWHERE. FORECASTING LUBBOCK AND CHILDRESS TO BOTH BREAK THEIR
RECORD LOWS OF 31 AND 35 RESPECTIVELY. WILL CONTINUE TO MONITOR
TRENDS FOR FREEZE WATCH ISSUANCE AND HOLD OFF FOR NOW TO ALLOW THE
WEATHER SCENARIO FOR TODAY/TONIGHT DISCUSSED IN THE SHORT TERM TO
PLAY OUT.
NORTHWEST FLOW AND RISING HEIGHTS WILL TAKE PLACE ALOFT IN WAKE OF
THE EXITING UPPER TROUGH AND GENERATE LEE TROUGHING ACROSS SOUTHEAST
COLORADO AND NORTHEAST NEW MEXICO FRIDAY...BACKING WINDS
SOUTH/SOUTHWESTERLY AND SUBSEQUENTLY WARMING TEMPERATURES BACK INTO
THE 60S WITH OVERNIGHT LOWS FRIDAY INTO SATURDAY REMAINING ABOVE THE
FREEZING MARK. WARMING LOOKS TO CONTINUE INTO THE WEEKEND BEFORE A
SUBTLE SHORTWAVE TROUGH BACKS THE UPPER FLOW AND SENDS A WEAK COOL
FRONT/WIND SHIFT TOWARD THE REGION...POSSIBLY STALLING BEFORE
CLEARING THE ROLLING PLAINS. THUS...DO NOT EXPECT HIGHS TO TAKE MUCH
OF A HIT FROM SATURDAY/S IN THE MID TO UPPER 70S.
MONDAY IS SETTING UP TO BE ANOTHER SEASONABLE DAY IN THE MID TO
UPPER 70S AS SOUTHERLY WINDS DRAW IN WARM AIR AHEAD OF A SURFACE LOW
NEAR THE TEXAS PANHANDLE. AN UPPER TROUGH DIGGING OUT OF THE
INTERMOUNTAIN WEST WILL BE APPROACHING ALOFT AND PROVIDING SOME
LARGE SCALE FORCING FOR ASCENT. WILL HAVE TO SEE HOW MOISTURE RETURN
PLAYS OUT AS TO WHETHER STORMS WILL BE POSSIBLE...MOST LIKELY IN THE
FAR SOUTHEAST PANHANDLE AND ROLLING PLAINS. WILL KEEP THE FORECAST
DRY AT THIS POINT GIVEN NWP INCONSISTENCIES IN THE INTENSITY OF THE
TROUGH AND ASSOCIATED COLD FRONT. NONETHELESS...TUESDAY LOOKS COOLER
ONCE AGAIN BEFORE TEMPERATURES REBOUND INTO MID-LATE WEEK AS HEIGHTS
INCREASE ALOFT.
FIRE WEATHER...
THERE APPEARS TO BE LITTLE DISAGREEMENT THAT STRONG SOUTHWEST WINDS
WILL DEVELOP FOR MOST IF NOT ALL LOCATIONS ON THE CAP-ROCK THIS
AFTERNOON LASTING INTO THE EARLY EVENING. THE PERIOD WITH STRONGEST
WINDS SHOULD BE LATE IN THE AFTERNOON PERHAPS INTO THE EARLY
EVENING. THERE REMAINS UNCERTAINTY...HOWEVER...ABOUT POTENTIAL FOR
THE STRONG DRY WINDS TO SCOUR OUT THE MOISTURE OVER THE ROLLING
PLAINS. WE FAVOR A BLEND THAT RETAINS A SOMEWHAT BACKED LOW LEVEL
FLOW ACROSS THE ROLLING PLAINS...ESPECIALLY THE FAR EASTERN ROW OF
COUNTIES THROUGH THE AFTERNOON. THIS STILL MAY ALLOW ELEVATED AND
EVEN BRIEFLY CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP FROM
BRISCOE AND HALL COUNTIES SOUTHWARD THROUGH KENT COUNTY. FUEL LOADS
REMAIN MINIMAL BUT THE ENERGY RELEASE COMPONENTS HAVE BECOME MORE
ELEVATED. SO...WE WILL ISSUE A RED FLAG WARNING FOR AREAS ON THE
CAPROCK WITH A FIRE DANGER STATEMENT FOR PORTIONS OF THE ROLLING
PLAINS AS WELL. RMCQUEEN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 30 48 24 60 35 / 10 0 0 0 0
TULIA 31 49 25 61 36 / 10 0 0 0 0
PLAINVIEW 34 51 26 61 38 / 10 0 0 0 0
LEVELLAND 34 54 28 63 37 / 0 0 0 0 0
LUBBOCK 37 54 29 62 40 / 0 0 0 0 0
DENVER CITY 39 55 29 62 39 / 0 0 0 0 0
BROWNFIELD 39 55 30 62 38 / 0 0 0 0 0
CHILDRESS 37 53 30 64 41 / 40 0 0 0 0
SPUR 41 55 30 64 38 / 20 0 0 0 0
ASPERMONT 47 57 31 65 40 / 40 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>023-027>030-033>036-039>042.
&&
$$
33
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1145 AM CDT WED APR 17 2013
.UPDATE...
THE CONVECTIVE FORECAST FOR THIS AFTERNOON AND EVENING IS TRICKY AS
IT HINGES ON THE COMPLEX INTERPLAY OF STRONG DYNAMICS ALOFT AND
SEVERAL MORE MESOSCALE-TYPE FEATURES AT THE SURFACE. AT 11 AM...A
SURFACE LOW WAS DEEPENING ACROSS ERN NM WITH A DRYLINE FORMING UP
ALONG THE NM/TX STATE LINE. FARTHER EAST...COOL...AND MOIST AIR
REMAINED BANKED UP AGAINST THE CAPROCK WITH A WARM FRONT NOSING
NORTHWARD INTO STONEWALL COUNTY. THIS IS CREATING QUITE A WIDE
RANGE OF SENSIBLE WX CONDITIONS ACROSS THE AREA LATE THIS MORNING.
MUCH OF THE MORNING MODEL GUIDANCE DO NOT HANDLE THE POSITION OF
THE SURFACE FEATURES WELL WHICH LOWERS CONFIDENCE IN THEIR
AFTERNOON PROJECTIONS.
THE GENERAL TREND OF THE FORECAST REMAINS INTACT THOUGH AS THE
DRYLINE SHOULD MIX ACROSS MOST OF THE CAPROCK. HOWEVER...THE
DRYLINE WILL ENCOUNTER MORE RESISTANCE ACROSS THE NORTH...NAMELY
SWISHER...BRISCOE AND FLOYD COUNTIES WHERE COOL UPSLOPE FLOW IS
PERSISTENT. THE 15Z RAP NEVER ERODES THIS COOL WEDGE AND INSTEAD
IT SERVES AS A BOUNDARY TO INITIATE CONVECTION AROUND 20 UTC.
OTHER GUIDANCE STILL TAKES THE DRYLINE FARTHER EAST...ALTHOUGH
PERHAPS NOT QUITE AS FAR AS PREVIOUSLY INDICATED. ANOTHER CONCERN
IS TEMPERATURES AND PROGRESS OF THE WARM SECTOR. WHILE THERE
SHOULD BE PLENTY OF CONDITIONAL INSTABILITY /SBCAPES IN EXCESS OF
2000 J/KG ACROSS THE ROLLING PLAINS...IT IS POSSIBLE THAT CLOUD
COVER AND COOLER TEMPS MAY HELP KEEP OUR NE ZONES CAPPED. WHILE IT
APPEARS THAT THE MOST LIKELY SCENARIO IS THAT T-STORM DEVELOPMENT WILL
BE FAVORED FROM ERN PORTIONS OF COTTLE AND KING COUNTIES NEWD TO
THE RED RIVER VALLEY WHERE THE DRYLINE/FRONT TRIPLE POINT IS
EXPECTED TO BE LOCATED...WE HAVE GONE AHEAD AND PULLED POPS BACK
WEST ACROSS THE FAR SRN PANHANDLE AND NRN ROLLING PLAINS IN CASE
1. THE DRYLINE HANGS UP FARTHER WEST IN THAT AREA...AND 2. THE CAP
CAN BREAK DESPITE THE COOLER TEMPS. CAPE AND SHEAR SHOULD BE MORE
THAN ADEQUATE FOR SUPERCELLS AND A THREAT OF HAIL/DAMAGING WINDS
AND ISOLATED TORNADOES...ESPECIALLY ALONG THE REMNANT FRONTAL
BOUNDARY...WHICH COULD BE PRESENT IN THE ERN ROLLING PLAINS.
&&
.PREV DISCUSSION... /ISSUED 658 AM CDT WED APR 17 2013/
AVIATION...
WE ARE STARTING OUT WITH AN LIFR CIG AND VSBY AT KCDS AND UNSETTLED
IFR TO MVFR CONDITIONS AT KLBB. TIMING THE IMPROVEMENT OF THESE
CONDITIONS WILL BE TRICKY...THOUGH KLBB WILL CERTAINLY IMPROVE
RAPIDLY BY MID MORNING OR SO...PERHAPS AN HOUR EARLIER OR LATER
THAN STATED IN THE TAF. VSBY AT KLBB LIKELY TO DETERIORATE HOWEVER
BY LATER IN THE AFTERNOON AS STRONG SOUTHWEST WINDS SHOULD BE ABLE
TO KICK BLOWING DUST INTO THE AIR WITH POSSIBLE MVFR VSBY ONCE
AGAIN. THERE IS GREATER UNCERTAINTY IN TIMING IMPROVEMENT AT KCDS
AS SOME SOLUTIONS INDICATE VERY LITTLE TO NO IMPROVEMENT WHILE
OTHERS INDICATE LOW CLOUDS COMPLETELY CLEARING OUT BY MID
AFTERNOON. WE HAVE KCDS PLAYED IN-BETWEEN THESE TWO CAMPS. A
STRONG COLD FRONT WILL ARRIVE DURING THE EVENING...EARLY AT KCDS
AND NEARER MIDNIGHT OR 06Z AT KLBB. THIS FRONT MAY PROVE A FOCUS
FOR SEVERE WEATHER MAINLY NEAR OR JUST EAST OF KCDS LATER TODAY SO
AVIATION USING THAT TERMINAL SHOULD PAY CONSIDERABLE ATTENTION TO
TAF UPDATES AND RADAR TRENDS. AN MVFR LAYER SEEMS MOST LIKELY AT
KCDS AGAIN TOWARDS THE END OF THIS FORECAST FOLLOWING THE
FRONT...AND LIKELY WILL OCCUR JUST BEYOND THIS FORECAST AT KLBB AS
WELL. RMCQUEEN
PREV DISCUSSION... /ISSUED 447 AM CDT WED APR 17 2013/
SHORT TERM...
LOW LEVEL MOISTURE WAS EDGING BACK WEST VIA ANOTHER WEAKENING AND
SHALLOW FRONTAL SLOSH THROUGH NORTHERN AND EASTERN ZONES AND
SOUTHEAST COMPONENT RETURNING MOISTURE ONTO THE CAPROCK. LIFT WAS
OCCURRING ALONG THE WESTERN BORDER WITH A WAVE LIFTING NORTHEAST
ACROSS THE AREA...BUT ONLY RESULTING IN MARGINAL ENHANCEMENT OF MID
AND HIGH CLOUDS. THUNDER WAS DEVELOPING MUCH FURTHER UPSTREAM OVER
THE CENTRAL PLAINS FROM THIS WAVE AS OUR AIRMASS REMAINED
CONSTRAINED BY A SOLID CAP NEAR THE 800 MB LEVEL. LOW CLOUDS SHOULD
EVENTUALLY EXPAND OVER MOST OF THE CENTRAL AND EASTERN AREAS BY
EARLY WEDNESDAY AND ALONG WITH LIGHT SHOWER OR DRIZZLE CHANCES
SHOULD BE THE DOMINANT WEATHER FOR THE MORNING. WE ALSO WILL SEE THE
LOW CLOUDS ERODE QUICKLY BY MID TO LATE MORNING ON THE CAPROCK WITH
DEEPER MIXING INTO THE STRONGER SOUTHWEST COMPONENTS ALOFT.
BY AFTERNOON THE DRY GUSTY SOUTHWEST WINDS SHOULD BE THE PRIMARY
WEATHER WITH MOISTURE CONTINUING TO ERODE SLOWLY THROUGH PARTS OF
THE ROLLING PLAINS AS WELL. CONSIDERABLE DISAGREEMENT REMAINS
BETWEEN MODEL CAMPS HOWEVER REGARDING NORTHWARD AND WESTWARD EXTENT
OF MIXED AIRMASS THROUGH THE ROLLING PLAINS. WE TEND TO LEAN TOWARDS
A MORE BACKED LOW LEVEL COMPONENT YET ARE NOT CONVINCED THAT AT
LEAST SOME PERIOD OF DEEP MIXING COULD ALSO WORK AS FAR NORTH AND
EAST AS CHILDRESS. A CONDITIONAL MENTION OF THUNDER AND SEVERE
STORMS WILL DEVELOP FROM THE FRONT AND DRY-LINE INTERSECTION
SOUTHWARD THROUGH EASTERN PORTIONS OF THE ROLLING PLAINS
ESPECIALLY...WHICH IS CONSISTENT WITH PREVIOUS FORECAST.
THUNDER CHANCES SHOULD INCREASE WITH ARRIVAL OF A STRONGER COLD
FRONT THIS EVENING THAT COULD FINALLY ALLOW CONVECTION TO DEEPEN AND
REALIZE THE CONSIDERABLE BUOYANT AND SHEARED ENVIRONMENT. THE SLOWLY
ERODING AND LIFTING CAP MAY STILL OFFER SOME RESISTANCE...HOWEVER...
THUS LIMITING CONFIDENCE FURTHER SOUTH THROUGH THE ROLLING PLAINS.
COLD FRONT WILL SURGE SOUTHWARD OVERNIGHT SPREADING LOW CLOUDS ONCE
MORE ACROSS MUCH OF THE AREA. WINDS MAY BECOME CLOSE TO WIND
ADVISORY LEVELS. PRECIPITATION CHANCES BEHIND THE FRONT APPEAR
SMALL...THOUGH WE RETAINED MINIMAL DRIZZLE MENTION NORTHERN ZONES
INCLUDING FREEZING DRIZZLE WITH TEMPERATURES EXPECTED TO DROP A
LITTLE BELOW FREEZING LATER TONIGHT ACROSS THE SOUTHWEST PANHANDLE
COUNTIES. RMCQUEEN
LONG TERM...
THURSDAY MORNING WILL START OFF BRISK ACROSS THE FAR SOUTHERN TEXAS
PANHANDLE...SOUTH PLAINS...AND ROLLING PLAINS BEHIND A STRONG COLD
FRONT EXHIBITING ABRUPT PRESSURE RISES. DO NOT BELIEVE WIND ADVISORY
CRITERIA WILL BE MET FOR AN EXTENDED PERIOD GIVEN AN OVERNIGHT
FRONTAL PASSAGE AND H70 200 NAUTICAL MILE HEIGHT GRADIENTS
SUPPORTING WINDS TOPPING OUT NEAR THE LOW END THRESHOLD OF 30 MPH.
SKIES SHOULD QUICKLY CLEAR AS DRIER AIR FILTERS IN ALONG WITH STOUT
COLD AIR ADVECTION ONLY ALLOWING HIGH TEMPERATURES TO REACH THE
UPPER 40S NORTHWEST TO MID-UPPER 50S SOUTHEAST. WINDS WILL DECREASE
THROUGH THE AFTERNOON AS JET MAX ALOFT PUSHES EAST AND PRESSURE
GRADIENT WEAKENS AHEAD OF APPROACHING SURFACE RIDGE FROM THE
ROCKIES. WHILE PORTIONS OF THE CAPROCK NORTH AND WEST OF LUBBOCK MAY
SEE FREEZING TEMPERATURES THURSDAY MORNING...A WIDESPREAD AND MUCH
HARDER FREEZE WILL TAKE PLACE FRIDAY MORNING AS CLEAR SKIES...LIGHT
WINDS...AND DRY CONDITIONS PROMOTE STRONG RADIATIONAL COOLING WITH
SURFACE RIDGING EXTENDING ACROSS THE AREA. NORTHWEST ZONES WILL
LIKELY BOTTOM OUT IN THE MID 20S WHILE UPPER 20S TO LOW 30S OCCUR
ELSEWHERE. FORECASTING LUBBOCK AND CHILDRESS TO BOTH BREAK THEIR
RECORD LOWS OF 31 AND 35 RESPECTIVELY. WILL CONTINUE TO MONITOR
TRENDS FOR FREEZE WATCH ISSUANCE AND HOLD OFF FOR NOW TO ALLOW THE
WEATHER SCENARIO FOR TODAY/TONIGHT DISCUSSED IN THE SHORT TERM TO
PLAY OUT.
NORTHWEST FLOW AND RISING HEIGHTS WILL TAKE PLACE ALOFT IN WAKE OF
THE EXITING UPPER TROUGH AND GENERATE LEE TROUGHING ACROSS SOUTHEAST
COLORADO AND NORTHEAST NEW MEXICO FRIDAY...BACKING WINDS
SOUTH/SOUTHWESTERLY AND SUBSEQUENTLY WARMING TEMPERATURES BACK INTO
THE 60S WITH OVERNIGHT LOWS FRIDAY INTO SATURDAY REMAINING ABOVE THE
FREEZING MARK. WARMING LOOKS TO CONTINUE INTO THE WEEKEND BEFORE A
SUBTLE SHORTWAVE TROUGH BACKS THE UPPER FLOW AND SENDS A WEAK COOL
FRONT/WIND SHIFT TOWARD THE REGION...POSSIBLY STALLING BEFORE
CLEARING THE ROLLING PLAINS. THUS...DO NOT EXPECT HIGHS TO TAKE MUCH
OF A HIT FROM SATURDAY/S IN THE MID TO UPPER 70S.
MONDAY IS SETTING UP TO BE ANOTHER SEASONABLE DAY IN THE MID TO
UPPER 70S AS SOUTHERLY WINDS DRAW IN WARM AIR AHEAD OF A SURFACE LOW
NEAR THE TEXAS PANHANDLE. AN UPPER TROUGH DIGGING OUT OF THE
INTERMOUNTAIN WEST WILL BE APPROACHING ALOFT AND PROVIDING SOME
LARGE SCALE FORCING FOR ASCENT. WILL HAVE TO SEE HOW MOISTURE RETURN
PLAYS OUT AS TO WHETHER STORMS WILL BE POSSIBLE...MOST LIKELY IN THE
FAR SOUTHEAST PANHANDLE AND ROLLING PLAINS. WILL KEEP THE FORECAST
DRY AT THIS POINT GIVEN NWP INCONSISTENCIES IN THE INTENSITY OF THE
TROUGH AND ASSOCIATED COLD FRONT. NONETHELESS...TUESDAY LOOKS COOLER
ONCE AGAIN BEFORE TEMPERATURES REBOUND INTO MID-LATE WEEK AS HEIGHTS
INCREASE ALOFT.
FIRE WEATHER...
THERE APPEARS TO BE LITTLE DISAGREEMENT THAT STRONG SOUTHWEST WINDS
WILL DEVELOP FOR MOST IF NOT ALL LOCATIONS ON THE CAP-ROCK THIS
AFTERNOON LASTING INTO THE EARLY EVENING. THE PERIOD WITH STRONGEST
WINDS SHOULD BE LATE IN THE AFTERNOON PERHAPS INTO THE EARLY
EVENING. THERE REMAINS UNCERTAINTY...HOWEVER...ABOUT POTENTIAL FOR
THE STRONG DRY WINDS TO SCOUR OUT THE MOISTURE OVER THE ROLLING
PLAINS. WE FAVOR A BLEND THAT RETAINS A SOMEWHAT BACKED LOW LEVEL
FLOW ACROSS THE ROLLING PLAINS...ESPECIALLY THE FAR EASTERN ROW OF
COUNTIES THROUGH THE AFTERNOON. THIS STILL MAY ALLOW ELEVATED AND
EVEN BRIEFLY CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP FROM
BRISCOE AND HALL COUNTIES SOUTHWARD THROUGH KENT COUNTY. FUEL LOADS
REMAIN MINIMAL BUT THE ENERGY RELEASE COMPONENTS HAVE BECOME MORE
ELEVATED. SO...WE WILL ISSUE A RED FLAG WARNING FOR AREAS ON THE
CAPROCK WITH A FIRE DANGER STATEMENT FOR PORTIONS OF THE ROLLING
PLAINS AS WELL. RMCQUEEN
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 81 30 48 24 60 / 0 10 0 0 0
TULIA 84 31 49 25 61 / 10 10 0 0 0
PLAINVIEW 86 34 51 26 61 / 10 10 0 0 0
LEVELLAND 85 34 54 28 63 / 0 0 0 0 0
LUBBOCK 87 37 54 29 62 / 10 0 0 0 0
DENVER CITY 85 39 55 29 62 / 0 0 0 0 0
BROWNFIELD 86 39 55 30 62 / 0 0 0 0 0
CHILDRESS 78 37 53 30 64 / 30 40 0 0 0
SPUR 89 41 55 30 64 / 20 20 0 0 0
ASPERMONT 87 47 57 31 65 / 20 40 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 9 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>023-027>030-033>036-039>042.
&&
$$
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