Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 03/13/12
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
215 PM EDT SUN MAR 11 2012
.UPDATE...
INCREASED THE SKY GRIDS IN THE WESTERN PORTION OF THE FORECAST
AREA TO HIGHLIGHT THE LATEST SATELLITE TREND AND SURFACE OBS.
OTHERWISE...NO OTHER CHANGES NEEDED AS MAX TEMPS...POPS AND
SURFACE WINDS ARE ON TRACK.
16
&&
.PREV DISCUSSION... /ISSUED 818 AM EDT SUN MAR 11 2012/
SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC CONTINUES TO DOMINATE
THE AREA TODAY WITH RIDGING BUILDING IN ALOFT AND GENERAL EASTERLY
FLOW AT THE SURFACE. EXPECT HIGH TEMPS ONLY SLIGHTLY WARMER TODAY
THAN YESTERDAY. CUTOFF LOW OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE NORTHEAST AS CLOUDS AND PRECIPITATION SPREAD OVER THE
LOWER MISSISSIPPI VALLEY. AS SURFACE FLOW SHIFTS TO MORE
SOUTHEASTERLY LATER TODAY IN RESPONSE TO THE APPROACHING FRONT...
ADDITIONAL MOISTURE WILL BE ADVECTED INTO THE REGION. THE NAM IS A
LITTLE STRONGER THAN MODEL CONSENSUS WITH THE SURFACE SYSTEM
APPROACHING THE AREA...WITH STRONGER SOUTHERLY FLOW AHEAD OF THE
FRONT. IT THUS HAS A FASTER PACE OF RETURN MOISTURE AND ISENTROPIC
LIFT. HAVE GENERALLY SIDED WITH THE GFS/ECMWF...BUT IN-HOUSE 4KM
WRF AND HRRR HINT THAT THE NAM MAY BE ONTO SOMETHING AND THAT
ISOLATED SHOWERS COULD DEVELOP IN RESPONSE TO THE ISENTROPIC
UPGLIDE TODAY. HAVE CONTINUED TREND OF SLIGHT CHANCE SHOWERS
BEGINNING EARLY THIS AFTERNOON MAINLY SOUTH AND WEST...ALONG THE
WESTERN PERIPHERY OF THE SURFACE HIGH.
LOW TEMPS TONIGHT /AS IN SUNDAY NIGHT/ WILL BE MARKEDLY HIGHER
THAN LOW TEMPS AT AFD TIME /SUNDAY MORNING LOWS/ DUE TO THE
MOISTURE INCREASE AND INCREASING CLOUD COVER. HIGH TEMPS MONDAY
SHOULD BEGIN THEIR SLOW BUT STEADY INCREASE THAT WILL CONTINUE
THROUGH THE WEEK. FRONT BEGINS TO APPROACH THE AREA ON MONDAY WITH
AFTERNOON CAPES PROGGED IN THE 200-400 J/KG RANGE MAINLY IN
EXTREME WESTERN ZONES. BEST CAPE REMAINS OVER ALABAMA BUT WITH THE
PROXIMITY OF THE FRONT...CANNOT RULE OUT THUNDER ON MONDAY
AFTERNOON BUT HAVE LIMITED IT TO SLIGHT CHANCE. POPS IN NORTH
GEORGIA REMAIN VERY HIGH BUT EXPECT LOW QPF AMOUNTS.
AS MAIN DYNAMICS LIFT NORTH WITH THE CLOSED LOW...WHICH WILL BE
ABSORBED BY THE LONGWAVE SYSTEM IN CANADA...THE FRONT BEGINS TO
STALL AND DISSIPATE. SOME UNCERTAINTY IN AMOUNT OF MOISTURE AND
LIFT AVAILABLE MONDAY NIGHT SO HAVE LIMITED POPS TO SLIGHT
CHANCE...BUT LATER FORECASTS MAY NEED TO INCREASE POPS ESPECIALLY
NORTH MONDAY AFTERNOON INTO MONDAY NIGHT.
TDP
LONG TERM /TUESDAY THROUGH SATURDAY/...
NEARLY ZONAL FLOW ALOFT KEEPS THE SURFACE FRONT FROM PROGRESSING
THROUGH THE CWA ON TUESDAY. HOWEVER THE CWA IS LEFT WITH INCREASING
MOIST SOUTHERLY FLOW. ALTHOUGH THE UPPER RIDGE BUILDS DURING THE
EXTENDED PERIOD...THE GFS ESPECIALLY SHOWS A SERIES OF SHORT WAVES
ORIGINATING IN THE SOUTHERN STREAM AND MOVING OVER THE RIDGE TO
AFFECT NORTH AND CENTRAL GEORGIA. ECMWF SHOWS THE SHORT WAVES BEING
PUSHED FURTHER TO OUR NORTH. WITH THIS UNCERTAIN PATTERN...LOW POPS
SEEM REASONABLE FOR EACH PERIOD. CAPES ARE FORECAST TO RANGE BETWEEN
500 AND 1000 DURING THE WEEK...SO HAVE LEFT IN A MENTION OF THUNDER
FOR EACH DAY. WITH RIDGING ALOFT...TEMPERATURES SHOULD REMAIN WARM
AND SHOULD BE A BIT ABOVE NORMAL FOR MOST AREAS.
41
AVIATION...
18Z UPDATE...
MIXTURE OF MOSTLY VFR WITH SCATTERED MVFR CONDITIONS CURRENTLY
SHOULD BECOME VFR AREAWIDE BY 20Z. MVFR CONDITIONS SPREAD NORTHWARD
ACROSS THE FORECAST AREA BETWEEN 02Z AND 06Z WITH IFR CONDITIONS
PREDOMINATING AFTER 10Z. SOME IMPROVEMENT POSSIBLE BACK INTO THE
MVFR RANGE AFTER 16Z. WINDS WILL REMAIN SOUTHEAST THROUGH THE
PERIOD. WINDS SPEEDS 7-10KT THROUGH 00Z WITH GUSTS 15-18KT...
BECOMING 5KT OR LESS THROUGH 13Z BEFORE BEGINNING TO INCREASE ONCE
AGAIN INTO THE 5-10KT RANGE. CHANCE OF RAIN WILL INCREASE AFTER
MIDNIGHT WITH SHOWERS LIKELY ACROSS NORTH GEORGIA BY EARLY MONDAY.
CHANCE OF ISOLATED THUNDER LIMITED TO AFTER 16Z MONDAY.
//ATL CONFIDENCE...18Z UPDATE...
HIGH ON WINDS.
MEDIUM OTHER ELEMENTS.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 48 66 52 / 10 30 40 40
ATLANTA 64 51 66 56 / 20 50 50 40
BLAIRSVILLE 62 46 59 50 / 10 70 80 50
CARTERSVILLE 64 51 66 54 / 20 70 80 50
COLUMBUS 67 55 73 58 / 20 30 40 40
GAINESVILLE 64 50 64 53 / 10 50 60 40
MACON 66 54 74 56 / 20 30 20 30
ROME 67 53 69 54 / 20 80 80 50
PEACHTREE CITY 65 52 69 52 / 20 50 50 40
VIDALIA 68 53 73 55 / 10 10 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1248 PM EDT SUN MAR 11 2012
.UPDATE...
INCREASED THE SKY GRIDS IN THE WESTERN PORTION OF THE FORECAST
AREA TO HIGHLIGHT THE LATEST SATELLITE TREND AND SURFACE OBS.
OTHERWISE...NO OTHER CHANGES NEEDED AS MAX TEMPS...POPS AND
SURFACE WINDS ARE ON TRACK.
16
&&
.PREV DISCUSSION... /ISSUED 818 AM EDT SUN MAR 11 2012/
SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC CONTINUES TO DOMINATE
THE AREA TODAY WITH RIDGING BUILDING IN ALOFT AND GENERAL EASTERLY
FLOW AT THE SURFACE. EXPECT HIGH TEMPS ONLY SLIGHTLY WARMER TODAY
THAN YESTERDAY. CUTOFF LOW OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE NORTHEAST AS CLOUDS AND PRECIPITATION SPREAD OVER THE
LOWER MISSISSIPPI VALLEY. AS SURFACE FLOW SHIFTS TO MORE
SOUTHEASTERLY LATER TODAY IN RESPONSE TO THE APPROACHING FRONT...
ADDITIONAL MOISTURE WILL BE ADVECTED INTO THE REGION. THE NAM IS A
LITTLE STRONGER THAN MODEL CONSENSUS WITH THE SURFACE SYSTEM
APPROACHING THE AREA...WITH STRONGER SOUTHERLY FLOW AHEAD OF THE
FRONT. IT THUS HAS A FASTER PACE OF RETURN MOISTURE AND ISENTROPIC
LIFT. HAVE GENERALLY SIDED WITH THE GFS/ECMWF...BUT IN-HOUSE 4KM
WRF AND HRRR HINT THAT THE NAM MAY BE ONTO SOMETHING AND THAT
ISOLATED SHOWERS COULD DEVELOP IN RESPONSE TO THE ISENTROPIC
UPGLIDE TODAY. HAVE CONTINUED TREND OF SLIGHT CHANCE SHOWERS
BEGINNING EARLY THIS AFTERNOON MAINLY SOUTH AND WEST...ALONG THE
WESTERN PERIPHERY OF THE SURFACE HIGH.
LOW TEMPS TONIGHT /AS IN SUNDAY NIGHT/ WILL BE MARKEDLY HIGHER
THAN LOW TEMPS AT AFD TIME /SUNDAY MORNING LOWS/ DUE TO THE
MOISTURE INCREASE AND INCREASING CLOUD COVER. HIGH TEMPS MONDAY
SHOULD BEGIN THEIR SLOW BUT STEADY INCREASE THAT WILL CONTINUE
THROUGH THE WEEK. FRONT BEGINS TO APPROACH THE AREA ON MONDAY WITH
AFTERNOON CAPES PROGGED IN THE 200-400 J/KG RANGE MAINLY IN
EXTREME WESTERN ZONES. BEST CAPE REMAINS OVER ALABAMA BUT WITH THE
PROXIMITY OF THE FRONT...CANNOT RULE OUT THUNDER ON MONDAY
AFTERNOON BUT HAVE LIMITED IT TO SLIGHT CHANCE. POPS IN NORTH
GEORGIA REMAIN VERY HIGH BUT EXPECT LOW QPF AMOUNTS.
AS MAIN DYNAMICS LIFT NORTH WITH THE CLOSED LOW...WHICH WILL BE
ABSORBED BY THE LONGWAVE SYSTEM IN CANADA...THE FRONT BEGINS TO
STALL AND DISSIPATE. SOME UNCERTAINTY IN AMOUNT OF MOISTURE AND
LIFT AVAILABLE MONDAY NIGHT SO HAVE LIMITED POPS TO SLIGHT
CHANCE...BUT LATER FORECASTS MAY NEED TO INCREASE POPS ESPECIALLY
NORTH MONDAY AFTERNOON INTO MONDAY NIGHT.
TDP
LONG TERM /TUESDAY THROUGH SATURDAY/...
NEARLY ZONAL FLOW ALOFT KEEPS THE SURFACE FRONT FROM PROGRESSING
THROUGH THE CWA ON TUESDAY. HOWEVER THE CWA IS LEFT WITH INCREASING
MOIST SOUTHERLY FLOW. ALTHOUGH THE UPPER RIDGE BUILDS DURING THE
EXTENDED PERIOD...THE GFS ESPECIALLY SHOWS A SERIES OF SHORT WAVES
ORIGINATING IN THE SOUTHERN STREAM AND MOVING OVER THE RIDGE TO
AFFECT NORTH AND CENTRAL GEORGIA. ECMWF SHOWS THE SHORT WAVES BEING
PUSHED FURTHER TO OUR NORTH. WITH THIS UNCERTAIN PATTERN...LOW POPS
SEEM REASONABLE FOR EACH PERIOD. CAPES ARE FORECAST TO RANGE BETWEEN
500 AND 1000 DURING THE WEEK...SO HAVE LEFT IN A MENTION OF THUNDER
FOR EACH DAY. WITH RIDGING ALOFT...TEMPERATURES SHOULD REMAIN WARM
AND SHOULD BE A BIT ABOVE NORMAL FOR MOST AREAS.
41
AVIATION...
12Z UPDATE...
LOW VFR TO MVFR CIGS MOVING IN ACROSS THE SOUTHERN TAF AREAS THIS
MORNING. THIS WILL CONTINUE TO SPREAD NORTH THROUGH THE MORNING
HOURS...WITH SOME BRIEF IMPROVEMENT POSSIBLE WITH THE HEATING OF
THE DAY AT NORTHERN TAFS. FOR SOUTHERN TAFS...EXPECT MVFR
CONDITIONS TO PREVAIL THROUGH THE DAY. AS THE FRONT APPROACHES
MOISTURE WILL INCREASE AND MVFR CIGS WILL LOWER EVERYWHERE AFTER
00Z WITH -SHRA MOVING IN AS WELL. TIMING OF IFR CIGS STILL UNCERTAIN
WITH SOME GUIDANCE BRINGING IT IN AS EARLY AS 03Z. HAVE CONTINUED
TREND FROM PREVIOUS TAF OF TAKING COMPROMISE AT 09Z. EAST TO
SOUTHEASTERLY WINDS THROUGH THE PERIOD 5-10KT WITH GUSTS 15-20KT
FROM APPROXIMATELY 15Z-00Z TODAY.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON WINDS.
MEDIUM ON VSBY.
HIGH ON OCCURRENCE OF MVFR CIGS...MEDIUM ON IFR.
MEDIUM ON TIMING OF MVFR CIGS...LOW ON IFR.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 48 66 52 / 10 30 40 40
ATLANTA 64 51 66 56 / 20 50 50 40
BLAIRSVILLE 62 46 59 50 / 10 70 80 50
CARTERSVILLE 64 51 66 54 / 20 70 80 50
COLUMBUS 67 55 73 58 / 20 30 40 40
GAINESVILLE 64 50 64 53 / 10 50 60 40
MACON 66 54 74 56 / 20 30 20 30
ROME 67 53 69 54 / 20 80 80 50
PEACHTREE CITY 65 52 69 52 / 20 50 50 40
VIDALIA 68 53 73 55 / 10 10 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
818 AM EDT SUN MAR 11 2012
.PREV DISCUSSION... /ISSUED 331 AM EDT SUN MAR 11 2012/
SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC CONTINUES TO DOMINATE
THE AREA TODAY WITH RIDGING BUILDING IN ALOFT AND GENERAL EASTERLY
FLOW AT THE SURFACE. EXPECT HIGH TEMPS ONLY SLIGHTLY WARMER TODAY
THAN YESTERDAY. CUTOFF LOW OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE NORTHEAST AS CLOUDS AND PRECIPITATION SPREAD OVER THE
LOWER MISSISSIPPI VALLEY. AS SURFACE FLOW SHIFTS TO MORE
SOUTHEASTERLY LATER TODAY IN RESPONSE TO THE APPROACHING FRONT...
ADDITIONAL MOISTURE WILL BE ADVECTED INTO THE REGION. THE NAM IS A
LITTLE STRONGER THAN MODEL CONSENSUS WITH THE SURFACE SYSTEM
APPROACHING THE AREA...WITH STRONGER SOUTHERLY FLOW AHEAD OF THE
FRONT. IT THUS HAS A FASTER PACE OF RETURN MOISTURE AND ISENTROPIC
LIFT. HAVE GENERALLY SIDED WITH THE GFS/ECMWF...BUT IN-HOUSE 4KM
WRF AND HRRR HINT THAT THE NAM MAY BE ONTO SOMETHING AND THAT
ISOLATED SHOWERS COULD DEVELOP IN RESPONSE TO THE ISENTROPIC
UPGLIDE TODAY. HAVE CONTINUED TREND OF SLIGHT CHANCE SHOWERS
BEGINNING EARLY THIS AFTERNOON MAINLY SOUTH AND WEST...ALONG THE
WESTERN PERIPHERY OF THE SURFACE HIGH.
LOW TEMPS TONIGHT /AS IN SUNDAY NIGHT/ WILL BE MARKEDLY HIGHER
THAN LOW TEMPS AT AFD TIME /SUNDAY MORNING LOWS/ DUE TO THE
MOISTURE INCREASE AND INCREASING CLOUD COVER. HIGH TEMPS MONDAY
SHOULD BEGIN THEIR SLOW BUT STEADY INCREASE THAT WILL CONTINUE
THROUGH THE WEEK. FRONT BEGINS TO APPROACH THE AREA ON MONDAY WITH
AFTERNOON CAPES PROGGED IN THE 200-400 J/KG RANGE MAINLY IN
EXTREME WESTERN ZONES. BEST CAPE REMAINS OVER ALABAMA BUT WITH THE
PROXIMITY OF THE FRONT...CANNOT RULE OUT THUNDER ON MONDAY
AFTERNOON BUT HAVE LIMITED IT TO SLIGHT CHANCE. POPS IN NORTH
GEORGIA REMAIN VERY HIGH BUT EXPECT LOW QPF AMOUNTS.
AS MAIN DYNAMICS LIFT NORTH WITH THE CLOSED LOW...WHICH WILL BE
ABSORBED BY THE LONGWAVE SYSTEM IN CANADA...THE FRONT BEGINS TO
STALL AND DISSIPATE. SOME UNCERTAINTY IN AMOUNT OF MOISTURE AND
LIFT AVAILABLE MONDAY NIGHT SO HAVE LIMITED POPS TO SLIGHT
CHANCE...BUT LATER FORECASTS MAY NEED TO INCREASE POPS ESPECIALLY
NORTH MONDAY AFTERNOON INTO MONDAY NIGHT.
TDP
LONG TERM /TUESDAY THROUGH SATURDAY/...
NEARLY ZONAL FLOW ALOFT KEEPS THE SURFACE FRONT FROM PROGRESSING
THROUGH THE CWA ON TUESDAY. HOWEVER THE CWA IS LEFT WITH INCREASING
MOIST SOUTHERLY FLOW. ALTHOUGH THE UPPER RIDGE BUILDS DURING THE
EXTENDED PERIOD...THE GFS ESPECIALLY SHOWS A SERIES OF SHORT WAVES
ORIGINATING IN THE SOUTHERN STREAM AND MOVING OVER THE RIDGE TO
AFFECT NORTH AND CENTRAL GEORGIA. ECMWF SHOWS THE SHORT WAVES BEING
PUSHED FURTHER TO OUR NORTH. WITH THIS UNCERTAIN PATTERN...LOW POPS
SEEM REASONABLE FOR EACH PERIOD. CAPES ARE FORECAST TO RANGE BETWEEN
500 AND 1000 DURING THE WEEK...SO HAVE LEFT IN A MENTION OF THUNDER
FOR EACH DAY. WITH RIDGING ALOFT...TEMPERATURES SHOULD REMAIN WARM
AND SHOULD BE A BIT ABOVE NORMAL FOR MOST AREAS.
41
&&
.AVIATION...
12Z UPDATE...
LOW VFR TO MVFR CIGS MOVING IN ACROSS THE SOUTHERN TAF AREAS THIS
MORNING. THIS WILL CONTINUE TO SPREAD NORTH THROUGH THE MORNING
HOURS...WITH SOME BRIEF IMPROVEMENT POSSIBLE WITH THE HEATING OF
THE DAY AT NORTHERN TAFS. FOR SOUTHERN TAFS...EXPECT MVFR
CONDITIONS TO PREVAIL THROUGH THE DAY. AS THE FRONT APPROACHES
MOISTURE WILL INCREASE AND MVFR CIGS WILL LOWER EVERYWHERE AFTER
00Z WITH -SHRA MOVING IN AS WELL. TIMING OF IFR CIGS STILL UNCERTAIN
WITH SOME GUIDANCE BRINGING IT IN AS EARLY AS 03Z. HAVE CONTINUED
TREND FROM PREVIOUS TAF OF TAKING COMPROMISE AT 09Z. EAST TO
SOUTHEASTERLY WINDS THROUGH THE PERIOD 5-10KT WITH GUSTS 15-20KT
FROM APPROXIMATELY 15Z-00Z TODAY.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON WINDS.
MEDIUM ON VSBY.
HIGH ON OCCURRENCE OF MVFR CIGS...MEDIUM ON IFR.
MEDIUM ON TIMING OF MVFR CIGS...LOW ON IFR.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 48 66 52 / 10 30 40 40
ATLANTA 64 51 66 56 / 20 50 50 40
BLAIRSVILLE 62 46 59 50 / 10 70 80 50
CARTERSVILLE 64 51 66 54 / 20 70 80 50
COLUMBUS 67 55 73 58 / 20 30 40 40
GAINESVILLE 64 50 64 53 / 10 50 60 40
MACON 66 54 74 56 / 20 30 20 30
ROME 67 53 69 54 / 20 80 80 50
PEACHTREE CITY 65 52 69 52 / 20 50 50 40
VIDALIA 68 53 73 55 / 10 10 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
331 AM EDT SUN MAR 11 2012
.SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
SURFACE HIGH PRESSURE OVER THE MID-ATLANTIC CONTINUES TO DOMINATE
THE AREA TODAY WITH RIDGING BUILDING IN ALOFT AND GENERAL EASTERLY
FLOW AT THE SURFACE. EXPECT HIGH TEMPS ONLY SLIGHTLY WARMER TODAY
THAN YESTERDAY. CUTOFF LOW OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE NORTHEAST AS CLOUDS AND PRECIPITATION SPREAD OVER THE
LOWER MISSISSIPPI VALLEY. AS SURFACE FLOW SHIFTS TO MORE
SOUTHEASTERLY LATER TODAY IN RESPONSE TO THE APPROACHING FRONT...
ADDITIONAL MOISTURE WILL BE ADVECTED INTO THE REGION. THE NAM IS A
LITTLE STRONGER THAN MODEL CONSENSUS WITH THE SURFACE SYSTEM
APPROACHING THE AREA...WITH STRONGER SOUTHERLY FLOW AHEAD OF THE
FRONT. IT THUS HAS A FASTER PACE OF RETURN MOISTURE AND ISENTROPIC
LIFT. HAVE GENERALLY SIDED WITH THE GFS/ECMWF...BUT IN-HOUSE 4KM
WRF AND HRRR HINT THAT THE NAM MAY BE ONTO SOMETHING AND THAT
ISOLATED SHOWERS COULD DEVELOP IN RESPONSE TO THE ISENTROPIC
UPGLIDE TODAY. HAVE CONTINUED TREND OF SLIGHT CHANCE SHOWERS
BEGINNING EARLY THIS AFTERNOON MAINLY SOUTH AND WEST...ALONG THE
WESTERN PERIPHERY OF THE SURFACE HIGH.
LOW TEMPS TONIGHT /AS IN SUNDAY NIGHT/ WILL BE MARKEDLY HIGHER
THAN LOW TEMPS AT AFD TIME /SUNDAY MORNING LOWS/ DUE TO THE
MOISTURE INCREASE AND INCREASING CLOUD COVER. HIGH TEMPS MONDAY
SHOULD BEGIN THEIR SLOW BUT STEADY INCREASE THAT WILL CONTINUE
THROUGH THE WEEK. FRONT BEGINS TO APPROACH THE AREA ON MONDAY WITH
AFTERNOON CAPES PROGGED IN THE 200-400 J/KG RANGE MAINLY IN
EXTREME WESTERN ZONES. BEST CAPE REMAINS OVER ALABAMA BUT WITH THE
PROXIMITY OF THE FRONT...CANNOT RULE OUT THUNDER ON MONDAY
AFTERNOON BUT HAVE LIMITED IT TO SLIGHT CHANCE. POPS IN NORTH
GEORGIA REMAIN VERY HIGH BUT EXPECT LOW QPF AMOUNTS.
AS MAIN DYNAMICS LIFT NORTH WITH THE CLOSED LOW...WHICH WILL BE
ABSORBED BY THE LONGWAVE SYSTEM IN CANADA...THE FRONT BEGINS TO
STALL AND DISSIPATE. SOME UNCERTAINTY IN AMOUNT OF MOISTURE AND
LIFT AVAILABLE MONDAY NIGHT SO HAVE LIMITED POPS TO SLIGHT
CHANCE...BUT LATER FORECASTS MAY NEED TO INCREASE POPS ESPECIALLY
NORTH MONDAY AFTERNOON INTO MONDAY NIGHT.
TDP
.LONG TERM /TUESDAY THROUGH SATURDAY/...
NEARLY ZONAL FLOW ALOFT KEEPS THE SURFACE FRONT FROM PROGRESSING
THROUGH THE CWA ON TUESDAY. HOWEVER THE CWA IS LEFT WITH INCREASING
MOIST SOUTHERLY FLOW. ALTHOUGH THE UPPER RIDGE BUILDS DURING THE
EXTENDED PERIOD...THE GFS ESPECIALLY SHOWS A SERIES OF SHORT WAVES
ORIGINATING IN THE SOUTHERN STREAM AND MOVING OVER THE RIDGE TO
AFFECT NORTH AND CENTRAL GEORGIA. ECMWF SHOWS THE SHORT WAVES BEING
PUSHED FURTHER TO OUR NORTH. WITH THIS UNCERTAIN PATTERN...LOW POPS
SEEM REASONABLE FOR EACH PERIOD. CAPES ARE FORECAST TO RANGE BETWEEN
500 AND 1000 DURING THE WEEK...SO HAVE LEFT IN A MENTION OF THUNDER
FOR EACH DAY. WITH RIDGING ALOFT...TEMPERATURES SHOULD REMAIN WARM
AND SHOULD BE A BIT ABOVE NORMAL FOR MOST AREAS.
41
&&
.AVIATION...
06Z UPDATE...
VFR THROUGH AT LEAST 00Z TONIGHT...THOUGH EARLY THIS MORNING
CIRRUS COVERAGE WILL INCREASE WITH LOW VFR CLOUDS BUILDING INTO
THE AREA BETWEEN 15-18Z. WINDS EAST TO SOUTHEASTERLY 5-10KT
THROUGH THE PERIOD...GUSTING TO 15-20KT BETWEEN APPROXIMATELY
15-00Z TODAY. AFTER 00Z...CIGS BEGIN TO LOWER WITH MVFR CIGS
MOVING IN WITH -SHRA IN THE METRO AREA JUST BEFORE 06Z. SOME
UNCERTAINTY WITH HOW LOW CIGS WILL DROP AFTER 06Z...HAVE
INTRODUCED IFR CONDITIONS AT ATL BUT HAVE KEPT IT AT OVC010.
//ATL CONFIDENCE...06Z UPDATE...
HIGH ON WINDS AND VSBY.
MEDIUM ON TIMING OF MVFR CIGS MOVING IN AND LOW ON
DEVELOPMENT/TIMING OF IFR CIGS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 48 66 52 / 10 30 40 40
ATLANTA 64 51 66 56 / 10 50 50 40
BLAIRSVILLE 62 46 59 50 / 10 60 60 50
CARTERSVILLE 64 51 66 54 / 10 70 70 50
COLUMBUS 67 55 73 58 / 10 30 30 40
GAINESVILLE 64 50 64 53 / 10 50 50 40
MACON 66 54 74 56 / 10 20 20 30
ROME 67 53 69 54 / 10 70 70 50
PEACHTREE CITY 65 52 69 52 / 10 50 50 40
VIDALIA 68 53 73 55 / 10 10 20 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BOISE ID
307 PM MDT SUN MAR 11 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY...COLD FRONT WITH ISOLATED
THUNDERSTORMS EXTENDED FROM AROUND DONNELLY TO JORDAN VALLEY AT
230 PM. EXPOSED FLAGSTAFF HILL RAWS GUSTED TO 64 MPH AS A
THUNDERSTORM CROSSED IT. A SPOTTER NEAR INDIAN VALLEY ESTIMATED
WIND GUSTS OF 50-60 MPH AS A SEPARATE THUNDERSTORM DEVELOPED
THERE...THEN WEAKENED AS IT MOVED TOWARDS THE LONG VALLEY. GUSTY
SW WINDS TO AROUND 50 MPH WERE REPORTED ACROSS A WIDE AREA WITH
AND BEHIND THE FRONT ESPECIALLY OVER HARNEY AND MALHEUR COUNTIES. GUSTY
WINDS WILL PROGRESS THROUGH SW IDAHO THEN DROP OFF AFTER SUNSET AS
A SURFACE HIGH PRESSURE RIDGE WITH WEAK GRADIENT CROSSES SE OREGON
AND SW IDAHO OVERNIGHT. SATELLITE GOES LI WERE NEGATIVE IS SPOTS
NORTH THROUGH WEST OF BOISE AS OF 2 PM AND THE RUC MODELED CAPE
EXCEEDED 200 J/KG IN EAST CENTRAL OREGON INCLUDING MUCH OF BAKER
COUNTY AT 18Z/NOON MDT. THE NEXT SYSTEM WILL AMPLIFY DRAMATICALLY
OFFSHORE BRINGING A ROUND OF SHOWERS AND GUSTY STRONG SOUTH WINDS
TO OREGON AND CLOUDS WITH LOW POPS AND LESS STRONG EAST TO SE
WINDS OVER IDAHO. THIS NEXT FRONT MOVES THROUGH SW IDAHO MONDAY
NIGHT AND TUESDAY MORNING. TIMING CHANGES ARE POSSIBLE AS THE
SYSTEM IS SO AMPLIFIED.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...A MOIST SOUTHWEST FLOW
ALOFT WILL HOLD TEMPERATURES 5 TO 8 DEGREES ABOVE NORMAL THROUGH
THURSDAY NIGHT. THERE WILL BE PRECIPITATION THROUGH THE PERIOD...
WITH THE BEST CHANCES TUESDAY NIGHT AND AGAIN THURSDAY NIGHT AND
FRIDAY. SNOW LEVELS WILL BE MAINLY ABOVE 5000 FEET TUESDAY NIGHT
RISING TO OVER 7000 FEET THURSDAY NIGHT. ON FRIDAY A COLD FRONT WILL
CROSS OUR AREA FOLLOWED BY MUCH COOLER WEATHER FOR THE WEEKEND AS A
MAJOR UPPER LEVEL TROUGH DEEPENS OVER THE WESTERN U.S. MAX
TEMPERATURES SATURDAY AND SUNDAY WILL BE 5 TO 10 DEGREES BELOW
NORMAL...WITH MINS RETURNING TO NEAR NORMAL FOR FRIDAY NIGHT AND
SATURDAY NIGHT. SHOWERS WILL BE SCATTERED...IN THE FORM OF SNOW OVER
THE MOUNTAINS AND A MIX OF SNOW AND RAIN IN THE VALLEYS.
&&
.AVIATION...THE LOWER VALLEYS WILL CONTINUE VFR WITH SCATTERED
SHOWERS. IN THE MOUNTAINS WIDESPREAD MVFR/LOCAL IFR SNOW SHOWERS
WILL DECREASE TO SCATTERED AFTER 06Z. EXPECT ISOLATED THUNDERSTORMS
WITH STRONG GUSTY WINDS OVER CENTRAL AND SOUTHWEST IDAHO UNTIL ABOUT
03Z AS A COLD FRONT CROSSES THE AREA. MONDAY WILL BE VFR WITH
SCATTERED SNOW SHOWERS OVER THE NORTHERN MOUNTAINS. SOUTHWEST TO
WEST SURFACE WINDS 15-25 KTS LOCALLY GUSTING OVER 40 KTS WILL
DECREASE AFTER 03Z. WINDS ALOFT WILL BE SOUTHWEST UP TO 30 KTS AT
10K FEET MSL. &&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING IDZ011>015-029-033.
OR...WIND ADVISORY UNTIL 6 PM MDT /5 PM PDT/ THIS EVENING ORZ061>064.
&&
$$
WEATHER.GOV/BOISE
SHORT TERM...VM
LONG TERM....JT/WH
AVIATION.....JT
AREA FORECAST DISCUSSION...CORRECTED
NWS INDIANAPOLIS IN
1027 PM EDT MON MAR 12 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH
TONIGHT...AS A WEAK FRONTAL BOUNDARY PASSES THROUGH THE LOWER GREAT
LAKES. HIGH PRESSURE WILL THEN BUILD IN THROUGH MIDWEEK...BRINGING
DRY AND UNSEASONABLY WARM WEATHER. CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURN BEGINNING WEDNESDAY NIGHT AND CONTINUING INTO
THE WEEKEND...AS MOISTURE INCREASES AND A FRONTAL BOUNDARY BECOMES
NEARLY STATIONARY NORTH OF THE FORECAST AREA.
&&
.NEAR TERM /REST OF TONIGHT/...
ISOLATED SHOWERS WILL REMAIN POSSIBLE MAINLY ACROSS THE FAR
NORTHERN AND EASTERN TIER OF THE FORECAST AREA OVERNIGHT AS A WEAK
BOUNDARY PUSHES ACROSS THE AREA. BASED ON INSTABILITY INDICES
APPEARS THUNDER ACTIVITY SHOULD REMAIN WELL NORTH OF THE CWA...SO
OPTED WITH THIS UPDATE TO REMOVE THUNDER MENTION AT THIS TIME.
OTHER...REST OF THE FORECAST APPEARS TO BE ON TRACK FOR PARTLY
CLOUDY SKIES ON AVERAGE AND LOW TEMPS ON ONLY GETTING DOWN INTO
THE 50S.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
THE MAIN FOCUS OF THIS SHORT TERM FORECAST WILL CONTINUE TO REMAIN
ON THE UNSEASONABLY WARM TEMPERATURES AND POP CHANCES TOWARD THE END
OF THE SHORT TERM TIMEFRAME.
UPPER RIDGE AND SURFACE HIGH PRESSURE MOVES TOWARD THE AREA
TUESDAY AND TUESDAY NIGHT...BRINGING DRY CONDITIONS TO THE OHIO
VALLEY. UNSEASONABLY WARM TEMPERATURES ARE EXPECTED TO CONTINUE
THROUGH THE ENTIRE SHORT RANGE...WITH A GRADUAL WARMING ON
WEDNESDAY AS THE SFC HIGH PRESSES EAST AND S/SW WINDS RETURN. NOT
MUCH CHANGE TO TEMPS AS THEY MATCHED UP WELL WITH MOS GUIDANCE.
STAYED ON THE HIGH SIDE OF ENSEMBLE MOS SPREAD ON WEDNESDAY AND
AFTER.
WITH MINOR UPPER LEVEL DISTURBANCES PUSHING TOWARD THE FORECAST AREA
UNDER SOUTHWEST FLOW ALOFT...POPS MAKE A RETURN TO THE FORECAST AREA
WEDNESDAY NIGHT...OWING TO INCREASING MOISTURE AND ISENTROPIC LIFT
AOA THE 300-305K SFCS. INCREASING GULF MOISTURE AND AT LEAST MODEST
INSTABILITY IS EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY.
THUS...KEPT THUNDER GOING IN WX GRIDS. ON THURSDAY AFTN...THE NAM
FCST SOUNDINGS HAS 2500-3000 J/KG OF CAPE FORECAST WITH A MEAGER
20KT 0-6KM BULK SHEAR...WHILE THE GFS IS LESS BULLISH WITH THE CAPE
AOA 900 J/KG. IF THE NAM PANS OUT AND CONVECTIVE TEMPERATURES ARE
REACHED...ISOLATED SEVERE MAY BE POSSIBLE ON THURSDAY. LARGE HAIL
BEING THE MAIN THREAT WITH A FREEZING LEVEL FROM 9-10K. RIGHT NOW
CONFIDENCE IS LOW IN THIS SCENARIO...AS MODEL FORECAST SOUNDINGS
DISAGREE. WILL CONTINUE TO MONITOR.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS INDICATE AN UPPER AIR DISTURBANCE WILL BE MOVING ACROSS OUR
REGION EARLY IN THE EXTENDED PERIOD AND WILL AFFECT OUR
WEATHER...ESPECIALLY THURSDAY NIGHT. WILL MENTION LIKELY POPS
HERE. OTHERWISE IT IS HARD TO KEY ON ANYTHING ONE SYSTEM FRIDAY
THROUGH SATURDAY EXCEPT MODELS HAVE US UNDER A WARM HUMID AIRMASS
AND CONTINUALLY ARE PRODUCING QPF ACROSS OUR REGION AND WILL
CONTINUE CHANCE POPS HERE..
ENSEMBLES AMPLIFY THE UPPER RIDGE STRONGLY ACROSS OUR REGION EARLY
NEXT WEEK AS A STRONG UPPER TROUGH MOVES INTO THE WESTERN U.S. WILL
CONTINUE WITH A DRY FORECAST FOR SUNDAY AND I HAVE DOUBTS ABOUT ANY
PRECIP MONDAY GIVEN THE STRENGTH OF THE UPPER HIGH. FOR NOW WILL
ONLY MENTION 20 PERCENT POPS FOR MONDAY.
AS FAR AS TEMPERATURES ARE CONCERNED...FOLLOWED ALL BLEND NUMBERS
EARLY ON AND THEN WENT WITH A MIX OF HPC AND ALL BLEND NUMBERS FROM
THE WEEKEND ON. I SUSPECT ALL BLEND MAY BE A BIT COOL DURING THE
DAY AND A BIT TOO WARM AT NIGHT SUNDAY AND MONDAY GIVEN THAT THE
AIRMASS WILL BE DRYING OUT SOME.
&&
.AVIATION /DISCUSSION FOR 130300Z TAF ISSUANCE/...
JUST TWEAKED CURRENT CONDITIONS. PREVIOUS DISCUSSION FOLLOWS...
SUSTAINED WINDS WILL DROP DURING THE NIGHT TO AROUND 5 - 10KTS BY
6Z. WHILE MAV SHOWS ONLY A COUPLE OF HOURS OF MVFR MAINLY BASED ON
VISIBILITIES OVERNIGHT...MET NUMBERS BRING IN MVFR AND THEN AROUND 6
HOURS OF IFR CEILINGS. BOTH NAM AND RUC FORECAST SOUNDINGS SUPPORT
THE INCLUSION OF IFR...AND VSREFS SHOW A MEAN OF MVFR CEILINGS OVER
THE ENTIRE AREA AFTER ABOUT 3-4Z WITH A HIGH PROBABILITY OF IFR
CEILINGS DEVELOPING AT LEAST OVER THE WEST AFTER 6Z. WILL FAVOR A
PREVAILING MVFR SOLUTION WITH PERHAPS THE INCLUSION OF A FEW HOURS
OF TEMPO IFR AT KIND AND KBMG BASED ON THE MORE NUMEROUS PESSIMISTIC
SOLUTIONS. WILL KEEP THE WESTERN SITES OUT OF THE IFR AS CEILINGS
MAY NOT BUILD BACK THAT FAR. CEILINGS SHOULD BE COMING BACK UP TO
VFR BETWEEN 12 AND 15Z. ON ANOTHER NOTE...MODELS ARE SHOWING SOME
POSSIBILITY THAT KLAF COULD SEE A SHOWER OR THUNDERSTORM TONIGHT IN
THE 3-6Z TIMEFRAME AT THE TAIL END OF A SQUALL LINE HEADING THROUGH
MICHIGAN. STILL LOOKS LIKE PROBABILITY IS LOW ENOUGH TO LEAVE OUT OF
FORECAST AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MRD
NEAR TERM...SMF
SHORT TERM...MRD
LONG TERM....JH
AVIATION...CP
AREA FORECAST DISCUSSION...CORRECTED
NWS INDIANAPOLIS IN
1013 PM EDT MON MAR 12 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH
TONIGHT...AS A WEAK FRONTAL BOUNDARY PASSES THROUGH THE LOWER GREAT
LAKES. HIGH PRESSURE WILL THEN BUILD IN THROUGH MIDWEEK...BRINGING
DRY AND UNSEASONABLY WARM WEATHER. CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURN BEGINNING WEDNESDAY NIGHT AND CONTINUING INTO
THE WEEKEND...AS MOISTURE INCREASES AND A FRONTAL BOUNDARY BECOMES
NEARLY STATIONARY NORTH OF THE FORECAST AREA.
&&
.NEAR TERM /REST OF TONIGHT/...
ISOLATED SHOWERS WILL REMAIN POSSIBLE MAINLY ACROSS THE FAR
NORTHERN AND EASTERN TIER OF THE FORECAST AREA OVERNIGHT AS A WEAK
BOUNDARY PUSHES ACROSS THE AREA. BASED ON INSTABILITY INDICES
APPEARS THUNDER ACTIVITY SHOULD REMAIN WELL NORTH OF THE CWA...SO
OPTED WITH THIS UPDATE TO REMOVE THUNDER MENTION AT THIS TIME.
OTHER...REST OF THE FORECAST APPEARS TO BE ON TRACK FOR PARTLY
CLOUDY SKIES ON AVERAGE AND LOW TEMPS ON ONLY GETTING DOWN INTO
THE 50S.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
THE MAIN FOCUS OF THIS SHORT TERM FORECAST WILL CONTINUE TO REMAIN
ON THE UNSEASONABLY WARM TEMPERATURES AND POP CHANCES TOWARD THE END
OF THE SHORT TERM TIMEFRAME.
UPPER RIDGE AND SURFACE HIGH PRESSURE MOVES TOWARD THE AREA
TUESDAY AND TUESDAY NIGHT...BRINGING DRY CONDITIONS TO THE OHIO
VALLEY. UNSEASONABLY WARM TEMPERATURES ARE EXPECTED TO CONTINUE
THROUGH THE ENTIRE SHORT RANGE...WITH A GRADUAL WARMING ON
WEDNESDAY AS THE SFC HIGH PRESSES EAST AND S/SW WINDS RETURN. NOT
MUCH CHANGE TO TEMPS AS THEY MATCHED UP WELL WITH MOS GUIDANCE.
STAYED ON THE HIGH SIDE OF ENSEMBLE MOS SPREAD ON WEDNESDAY AND
AFTER.
WITH MINOR UPPER LEVEL DISTURBANCES PUSHING TOWARD THE FORECAST AREA
UNDER SOUTHWEST FLOW ALOFT...POPS MAKE A RETURN TO THE FORECAST AREA
WEDNESDAY NIGHT...OWING TO INCREASING MOISTURE AND ISENTROPIC LIFT
AOA THE 300-305K SFCS. INCREASING GULF MOISTURE AND AT LEAST MODEST
INSTABILITY IS EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY.
THUS...KEPT THUNDER GOING IN WX GRIDS. ON THURSDAY AFTN...THE NAM
FCST SOUNDINGS HAS 2500-3000 J/KG OF CAPE FORECAST WITH A MEAGER
20KT 0-6KM BULK SHEAR...WHILE THE GFS IS LESS BULLISH WITH THE CAPE
AOA 900 J/KG. IF THE NAM PANS OUT AND CONVECTIVE TEMPERATURES ARE
REACHED...ISOLATED SEVERE MAY BE POSSIBLE ON THURSDAY. LARGE HAIL
BEING THE MAIN THREAT WITH A FREEZING LEVEL FROM 9-10K. RIGHT NOW
CONFIDENCE IS LOW IN THIS SCENARIO...AS MODEL FORECAST SOUNDINGS
DISAGREE. WILL CONTINUE TO MONITOR.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS INDICATE AN UPPER AIR DISTURBANCE WILL BE MOVING ACROSS OUR
REGION EARLY IN THE EXTENDED PERIOD AND WILL AFFECT OUR
WEATHER...ESPECIALLY THURSDAY NIGHT. WILL MENTION LIKELY POPS
HERE. OTHERWISE IT IS HARD TO KEY ON ANYTHING ONE SYSTEM FRIDAY
THROUGH SATURDAY EXCEPT MODELS HAVE US UNDER A WARM HUMID AIRMASS
AND CONTINUALLY ARE PRODUCING QPF ACROSS OUR REGION AND WILL
CONTINUE CHANCE POPS HERE..
ENSEMBLES AMPLIFY THE UPPER RIDGE STRONGLY ACROSS OUR REGION EARLY
NEXT WEEK AS A STRONG UPPER TROUGH MOVES INTO THE WESTERN U.S. WILL
CONTINUE WITH A DRY FORECAST FOR SUNDAY AND I HAVE DOUBTS ABOUT ANY
PRECIP MONDAY GIVEN THE STRENGTH OF THE UPPER HIGH. FOR NOW WILL
ONLY MENTION 20 PERCENT POPS FOR MONDAY.
AS FAR AS TEMPERATURES ARE CONCERNED...FOLLOWED ALL BLEND NUMBERS
EARLY ON AND THEN WENT WITH A MIX OF HPC AND ALL BLEND NUMBERS FROM
THE WEEKEND ON. I SUSPECT ALL BLEND MAY BE A BIT COOL DURING THE
DAY AND A BIT TOO WARM AT NIGHT SUNDAY AND MONDAY GIVEN THAT THE
AIRMASS WILL BE DRYING OUT SOME.
&&
.AVIATION /DISCUSSION FOR 130000Z TAF ISSUANCE/...
WIND GUSTS OUT OF THE SOUTHWEST OF 20-30 KTS SHOULD BE DROPPING
OFF AROUND THE TIME OF ISSUANCE BUT MAY SEE ISOLATED GUSTS HANG
ON THROUGH 0-1Z BEFORE DROPPING OFF COMPLETELY. SUSTAINED WINDS
WILL DROP DURING THE NIGHT TO AROUND 5 - 10KTS BY 6Z. WHILE MAV
SHOWS ONLY A COUPLE OF HOURS OF MVFR MAINLY BASED ON VISIBILITIES
OVERNIGHT...MET NUMBERS BRING IN MVFR AND THEN AROUND 6 HOURS OF
IFR CEILINGS. BOTH NAM AND RUC FORECAST SOUNDINGS SUPPORT THE
INCLUSION OF IFR...AND VSREFS SHOW A MEAN OF MVFR CEILINGS OVER
THE ENTIRE AREA AFTER ABOUT 3-4Z WITH A HIGH PROBABILITY OF IFR
CEILINGS DEVELOPING AT LEAST OVER THE WEST AFTER 6Z. WILL FAVOR A
PREVAILING MVFR SOLUTION WITH PERHAPS THE INCLUSION OF A FEW HOURS
OF TEMPO IFR AT KIND AND KBMG BASED ON THE MORE NUMEROUS
PESSIMISTIC SOLUTIONS. WILL KEEP THE WESTERN SITES OUT OF THE IFR
AS CEILINGS MAY NOT BUILD BACK THAT FAR. CEILINGS SHOULD BE COMING
BACK UP TO VFR BETWEEN 12 AND 15Z. ON ANOTHER NOTE...MODELS ARE
SHOWING SOME POSSIBILITY THAT KLAF COULD SEE A SHOWER OR
THUNDERSTORM TONIGHT IN THE 3-6Z TIMEFRAME AT THE TAIL END OF A
SQUALL LINE HEADING THROUGH MICHIGAN. STILL LOOKS LIKE PROBABILITY
IS LOW ENOUGH TO LEAVE OUT OF FORECAST AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MRD
NEAR TERM...SMF
SHORT TERM...MRD
LONG TERM....JH
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1009 PM EDT MON MAR 12 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISOLATED SHOWERS AND THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH
TONIGHT...AS A WEAK FRONTAL BOUNDARY PASSES THROUGH THE LOWER GREAT
LAKES. HIGH PRESSURE WILL THEN BUILD IN THROUGH MIDWEEK...BRINGING
DRY AND UNSEASONABLY WARM WEATHER. CHANCES FOR SHOWERS AND
THUNDERSTORMS RETURN BEGINNING WEDNESDAY NIGHT AND CONTINUING INTO
THE WEEKEND...AS MOISTURE INCREASES AND A FRONTAL BOUNDARY BECOMES
NEARLY STATIONARY NORTH OF THE FORECAST AREA.
&&
.NEAR TERM /REST OF TONIGHT/...
ISOLATED SHOWERS WILL REMAIN POSSIBLE MAINLY ACROSS THE FAR
NORTHERN AND EASTERN TIER OF THE FORECAST AREA OVERNIGHT AS A WEAK
BOUNDARY LIFTS NORTH OVER THE AREA. BASED ON INSTABILITY INDICES
APPEARS THUNDER ACTIVITY SHOULD REMAIN WELL NORTH OF THE CWA FOR
OPTED TO REMOVE THUNDER MENTION AT THIS TIME. OTHER...REST OF THE
FORECAST APPEARS TO BE ON TRACK FOR PARTLY CLOUDY SKIES ON AVERAGE
AND LOW TEMPS ON ONLY GETTING DOWN INTO THE 50S.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
THE MAIN FOCUS OF THIS SHORT TERM FORECAST WILL CONTINUE TO REMAIN
ON THE UNSEASONABLY WARM TEMPERATURES AND POP CHANCES TOWARD THE END
OF THE SHORT TERM TIMEFRAME.
UPPER RIDGE AND SURFACE HIGH PRESSURE MOVES TOWARD THE AREA
TUESDAY AND TUESDAY NIGHT...BRINGING DRY CONDITIONS TO THE OHIO
VALLEY. UNSEASONABLY WARM TEMPERATURES ARE EXPECTED TO CONTINUE
THROUGH THE ENTIRE SHORT RANGE...WITH A GRADUAL WARMING ON
WEDNESDAY AS THE SFC HIGH PRESSES EAST AND S/SW WINDS RETURN. NOT
MUCH CHANGE TO TEMPS AS THEY MATCHED UP WELL WITH MOS GUIDANCE.
STAYED ON THE HIGH SIDE OF ENSEMBLE MOS SPREAD ON WEDNESDAY AND
AFTER.
WITH MINOR UPPER LEVEL DISTURBANCES PUSHING TOWARD THE FORECAST AREA
UNDER SOUTHWEST FLOW ALOFT...POPS MAKE A RETURN TO THE FORECAST AREA
WEDNESDAY NIGHT...OWING TO INCREASING MOISTURE AND ISENTROPIC LIFT
AOA THE 300-305K SFCS. INCREASING GULF MOISTURE AND AT LEAST MODEST
INSTABILITY IS EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY.
THUS...KEPT THUNDER GOING IN WX GRIDS. ON THURSDAY AFTN...THE NAM
FCST SOUNDINGS HAS 2500-3000 J/KG OF CAPE FORECAST WITH A MEAGER
20KT 0-6KM BULK SHEAR...WHILE THE GFS IS LESS BULLISH WITH THE CAPE
AOA 900 J/KG. IF THE NAM PANS OUT AND CONVECTIVE TEMPERATURES ARE
REACHED...ISOLATED SEVERE MAY BE POSSIBLE ON THURSDAY. LARGE HAIL
BEING THE MAIN THREAT WITH A FREEZING LEVEL FROM 9-10K. RIGHT NOW
CONFIDENCE IS LOW IN THIS SCENARIO...AS MODEL FORECAST SOUNDINGS
DISAGREE. WILL CONTINUE TO MONITOR.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS INDICATE AN UPPER AIR DISTURBANCE WILL BE MOVING ACROSS OUR
REGION EARLY IN THE EXTENDED PERIOD AND WILL AFFECT OUR
WEATHER...ESPECIALLY THURSDAY NIGHT. WILL MENTION LIKELY POPS
HERE. OTHERWISE IT IS HARD TO KEY ON ANYTHING ONE SYSTEM FRIDAY
THROUGH SATURDAY EXCEPT MODELS HAVE US UNDER A WARM HUMID AIRMASS
AND CONTINUALLY ARE PRODUCING QPF ACROSS OUR REGION AND WILL
CONTINUE CHANCE POPS HERE..
ENSEMBLES AMPLIFY THE UPPER RIDGE STRONGLY ACROSS OUR REGION EARLY
NEXT WEEK AS A STRONG UPPER TROUGH MOVES INTO THE WESTERN U.S. WILL
CONTINUE WITH A DRY FORECAST FOR SUNDAY AND I HAVE DOUBTS ABOUT ANY
PRECIP MONDAY GIVEN THE STRENGTH OF THE UPPER HIGH. FOR NOW WILL
ONLY MENTION 20 PERCENT POPS FOR MONDAY.
AS FAR AS TEMPERATURES ARE CONCERNED...FOLLOWED ALL BLEND NUMBERS
EARLY ON AND THEN WENT WITH A MIX OF HPC AND ALL BLEND NUMBERS FROM
THE WEEKEND ON. I SUSPECT ALL BLEND MAY BE A BIT COOL DURING THE
DAY AND A BIT TOO WARM AT NIGHT SUNDAY AND MONDAY GIVEN THAT THE
AIRMASS WILL BE DRYING OUT SOME.
&&
.AVIATION /DISCUSSION FOR 130000Z TAF ISSUANCE/...
WIND GUSTS OUT OF THE SOUTHWEST OF 20-30 KTS SHOULD BE DROPPING
OFF AROUND THE TIME OF ISSUANCE BUT MAY SEE ISOLATED GUSTS HANG
ON THROUGH 0-1Z BEFORE DROPPING OFF COMPLETELY. SUSTAINED WINDS
WILL DROP DURING THE NIGHT TO AROUND 5 - 10KTS BY 6Z. WHILE MAV
SHOWS ONLY A COUPLE OF HOURS OF MVFR MAINLY BASED ON VISIBILITIES
OVERNIGHT...MET NUMBERS BRING IN MVFR AND THEN AROUND 6 HOURS OF
IFR CEILINGS. BOTH NAM AND RUC FORECAST SOUNDINGS SUPPORT THE
INCLUSION OF IFR...AND VSREFS SHOW A MEAN OF MVFR CEILINGS OVER
THE ENTIRE AREA AFTER ABOUT 3-4Z WITH A HIGH PROBABILITY OF IFR
CEILINGS DEVELOPING AT LEAST OVER THE WEST AFTER 6Z. WILL FAVOR A
PREVAILING MVFR SOLUTION WITH PERHAPS THE INCLUSION OF A FEW HOURS
OF TEMPO IFR AT KIND AND KBMG BASED ON THE MORE NUMEROUS
PESSIMISTIC SOLUTIONS. WILL KEEP THE WESTERN SITES OUT OF THE IFR
AS CEILINGS MAY NOT BUILD BACK THAT FAR. CEILINGS SHOULD BE COMING
BACK UP TO VFR BETWEEN 12 AND 15Z. ON ANOTHER NOTE...MODELS ARE
SHOWING SOME POSSIBILITY THAT KLAF COULD SEE A SHOWER OR
THUNDERSTORM TONIGHT IN THE 3-6Z TIMEFRAME AT THE TAIL END OF A
SQUALL LINE HEADING THROUGH MICHIGAN. STILL LOOKS LIKE PROBABILITY
IS LOW ENOUGH TO LEAVE OUT OF FORECAST AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MRD
NEAR TERM...SMF
SHORT TERM...MRD
LONG TERM....JH
AVIATION...CP
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
719 PM EDT MON MAR 12 2012
.AVIATION... / 00Z TAFS /
MAIN FOCUS THIS EVENING IS CONVECTIVE EVOLUTION ALONG A SEWD SINKING
LOW LEVEL CONVERGENT BOUNDARY. THIS AREA OF MOISTURE CONVERGENCE
WILL WEAKEN A BIT WITH TIME AS PRIMARY SHORTWAVE AND MID LVL JET
MAXIMA SHIFT OFF TO THE NORTHEAST...ALTHOUGH SHOULD SEE AT LEAST SCT
CONVECTION MAKE IT TO FWA BTW 02-05Z PER LATEST HRRR GUIDANCE AS
A WEAKER SECONDARY VORT MAX ROTATES THROUGH THE SRN GREAT LAKES.
SBN APPEARS TO BE IN THE CLEAR AS WINDS HAVE VEERED MORE WESTERLY
JUST BEHIND THE FRONT. DECOUPLING COMBINED WITH SOME LINGERING
LOW LVL MOISTURE ALONG AND JUST BEHIND THIS FEATURE MAY ALLOW FOR
MVFR VIS RESTRICTIONS TOWARDS DAYBREAK TOMORROW AT FWA.
OTHERWISE...VFR WITH LITTLE IN THE WAY OF CLOUD COVER AS LOW LEVEL
RIDGING BUILDS IN FROM THE WEST.
&&
.PREV DISCUSSION... /ISSUED 338 PM EDT MON MAR 12 2012/
SHORT TERM.../TONIGHT THROUGH TUESDAY NIGHT/
MAIN FOCUS ON NEAR TERM CONVECTIVE POTENTIAL THROUGH EARLY EVENING
WITH MUCH QUIETER TUES/TUES NGT IN STORE.
SFC BASED INSTABILITY CONTINUES TO EXPAND ACROSS CENTRAL ILLINOIS
INTO WESTERN INDIANA AND FAR SW MICHIGAN IN ASSOCIATION WITH UPPER
LOW MOVING ACROSS THE WESTERN GREAT LAKES. SVR PARAMETERS IN PLACE
FOR STG-SVR STORMS LATE AFTERNOON INTO EARLY EVENING WITH ANY SFC
BASED CONVECTION HAVING 1) CAPES 500-1000 J/KG 2) EFFECTIVE SHEAR OF
50 TO 60 KTS 3) SFC BASED LI`S -3 TO -5 C. SOME INDICATIONS OF
INCREASING LL CONVERGENCE AND FORCING BEING NOTED ACROSS NORTHERN
ILLINOIS WHERE NEW CONVECTION WAS ATTEMPTING TO FIRE JUST WEST OF
BEST INSTABILITY. SLOW OVERALL MVMT SUGGEST IT WILL TAKE TILL AFTER
22Z IF NOT A BIT LATER FOR CONVECTION TO MAKE IT IN HERE. HAVE
EXPANDED NUMEROUS STORM WORDING FURTHER SOUTH IN CWA TO MATCH WITH
30 PERCENT PROB FOR DAMAGING WINDS. GIVEN MODEL TRENDS...THINK
ENTIRE AREA WILL STILL SEE AT LEAST A CHANCE FOR A SHOWER OR STORM.
WILL HOLD OFF ON ADDITION OF SVR MENTION FOR THE TIME BEING. MODELS
LINGER PRECIP INTO THE OVERNIGHT HOURS ACROSS MAINLY NORTHERN AREAS.
DID NOT EXPAND POPS ANY FURTHER SINCE LESS FAVORABLE TIME OF THE DAY
AND BEST FORCING WILL BE SHIFTING WELL NORTH.
MOSTLY SUNNY TO SUNNY SKIES ARE EXPECTED BY LATE TUESDAY MORNING
ACROSS THE AREA AS SUBSIDENCE ALLOWS FOR INCREASED MIXING AND
LOWERING OF RH VALUES. TEMPS SHOULD REBOUND BACK INTO MID TO UPPER
60S IN MOST LOCATIONS EXPECT ALONG LAKE SHORE AREAS WITH ONSHORE
FLOW/LAKE BREEZE DEVELOPMENT TO HINDER FULL MIXING. OVERNIGHT LOWS
WILL FALL BACK INTO THE LOW TO MID 40S TUES NGT.&&
LONG TERM.../WED-MON/
SHRTWV EXPECTED TO TRACK ACROSS WRN CANADA TO MANITOBA WED WITH
UPR RIDGE IN ADVANCE OF IT BUILDING THROUGH THE GRTLKS TO ERN
ONTARIO. THIS SHOULD RESULT IN VERY WARM TEMPS IN OUR AREA WITH
NEAR RECORD HIGHS IN THE M-U70S WED. SOME FLATTENING OF THE RIDGE
EXPECTED THU-FRI AS THE SRN EXTENT OF THE SHRTWV MOVES ACROSS THE
GRTLKS. WK SFC CDFNT ASSOCIATED WITH THIS SHRTWV EXPECTED TO SAG
SLOWLY SE INTO OUR AREA THU-FRI... AND THEN LIFT SLOWLY NORTH
SATURDAY-MONDAY AS UPR LEVEL FLOW OVER N.AM. AMPLIFIES ONCE AGAIN
AS DEEPENING TROF MOVES INTO WRN U.S. AND RIDGE BUILDS IN THE
EAST. WITH A MOIST AND UNSTABLE AIRMASS IN PLACE OVER OUR AREA
THROUGH THIS TIMEFRAME... THE COMBINATION OF THE WK SFC BOUNDARY IN
THE AREA AND POTENTIAL FOR WK SHRTWVS EJECTING NE FROM THE WEST
COAST TROF SUGGESTS LOW CHC OF TSTMS THROUGH MUCH OF THE PERIOD.
BEST CHC ATTM APPEARS TO BE THU WHEN FRONT INITIALLY SAGS INTO THE
AREA. SEVERAL NEGATIVE FACTORS WRT DEEP CONVECTION THROUGH THIS
PERIOD...ESPECIALLY FRI-MON INCLUDING UNCERTAINTY ON WHERE THE SFC
BOUNDARY WILL STALL...DIFFERENCES IN TIMING OF WK SHRTWV`S LIFTING
NE THROUGH THE AREA... AND POTENTIAL FOR CAPPING THROUGH MUCH OF
THE PERIOD. TEMPS SHOULD COOL A BIT INTO THE 60S OVER MOST OF THE
AREA THU-FRI WITH SFC BOUNDARY IN THE AREA... THEN WARM BACK UP
INTO THE 70S SAT-MON AS RIDGE ALOFT REBUILDS AND SFC BOUNDARY LIKELY
LIFTS NORTH.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
648 PM CDT MON MAR 12 2012
.AVIATION...
AVIATION...
VFR CONDITIONS TO CONTINUE THROUGH 00Z/14. SKIES WILL CLEAR WITHIN
A COUPLE OF HOURS AFTER SUNSET AND REMAIN CLEAR THROUGH TOMORROW NIGHT
AS WEAK HIGH PRESSURE MOVES IN. LIGHT WESTERLY WINDS WILL BECOME
NEARLY CALM TUESDAY MORNING BEFORE SHIFTING TO THE SOUTH IN THE
AFTERNOON. ..NICHOLS..
&&
.PREV DISCUSSION... /ISSUED 310 PM CDT MON MAR 12 2012/
SYNOPSIS...
12Z UA ANALYSIS HAD A 700MB LOW OVER WESTERN MINNESOTA WITH SEVERAL
TROFS RUNNING FROM THE WESTERN GREAT LAKES BACK INTO THE PLAINS. A
MODERATELY STRONG LLJ RAN FROM THE OKLAHOMA PANHANDLE INTO THE GREAT
LAKES. SATELLITE TRENDS SHOWS A VORT MAX MOVING FROM NORTHERN
MISSOURI INTO NORTHERN ILLINOIS WHILE THE MAIN VORT MAX MOVES INTO
NORTHERN WISCONSIN. RADAR SHOWS SPRINKLES OVER THE AREA WITH SOME
LOW CONVECTION OVER NORTHEAST ILLINOIS.
18Z SFC ANALYSIS HAS A WEAK LOW NEAR KDLH WITH A WARM FRONT RUNNING
SOUTHEAST TO NEAR DETROIT. A COLD FRONT RAN FROM THE LOW SOUTH TO
KUIN. DEW POINTS WERE IN THE 50S AND 60S OVER THE GREAT LAKES AND
LOWER MISSISSIPPI VALLEY WITH 30S AND 40S OVER MUCH OF THE PLAINS.
SHORT TERM...TONIGHT AND TUESDAY...
REFER TO THE CLIMATE SECTION BELOW FOR RECORD HIGHS FOR MARCH 13TH
AND 14TH.
CURRENT OBSERVATIONS THROUGH 20Z COMBINED WITH RECENT RUC TRENDS
INDICATE THE WINDOW OF OPPORTUNITY FOR ANY NEW CONVECTION IS
CLOSING. RADAR INDICATES SPRINKLES WITH SOME VERY MINOR SHOWERS OVER
THE SOUTHEAST HALF OF THE CWFA BUT RUC TRENDS INDICATE THE
INSTABILITY NEEDED TO GET ANYTHING STRONGER GOING WILL END BY 2130Z.
THUS SPRINKLES WITH PERHAPS A FEW SHRA WILL CONTINUE THROUGH SUNSET
WITH POSSIBLY AN ISOLD TSRA IN THE FAR EASTERN/SOUTHEASTERN CWFA.
SATELLITE TRENDS INDICATE THE CLOUDS ARE TAKING ON A MORE CELLULAR
NATURE AND WILL SLOWLY DISSIPATE WITH SUNSET.
SO A CLEARING TREND WILL OCCUR TONIGHT AS THE STORM SYSTEM MOVES
INTO CANADA. HIGH PRESSURE BUILDING INTO THE CWFA LATE TONIGHT WILL
RESULT IN LIGHT WINDS WHICH SHOULD ALLOW TEMPERATURES TO BECOME
CHILLY BUT STILL ABOVE NORMAL.
THE HIGH WILL INITIALLY LIMIT MIXING ON TUESDAY UNTIL IT MOVES EAST
OF THE AREA. RETURN FLOW DEVELOPING BY MID DAY COMBINED WITH THE
STRONG MARCH SUN WILL ALLOW TEMPERATURES TO CLIMB WELL ABOVE NORMAL.
THE NORTHERN THIRD OR SO OF THE CWFA SHOULD REACH THE UPPER 60S WITH
70 TO 75 ELSEWHERE. ..08..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BOTH SFC AND UPPER RIDGE
AXIS WILL MIGRATE OFF TO THE EAST OF THE CWA INTO WED MORNING
ALLOWING RETURN FLOW TO INCREASE LATE TUE NIGHT FOR NON-DIURNAL
TEMP CURVES. LOWS WILL PROBABLY OCCUR FROM 03Z-07Z WED BEFORE STEADY
TO SLOW RISE TREND BEGINS. AS SFC FRONT TRIES TO SAG TOWARD THE CWA
FROM THE NORTHWEST...THE CWA WILL BECOME UNDER FULL INFLUENCE OF
WARM THRUST. ONLY THE WET BIASED 12Z GFS BREAKS OUT PRECIP ON WED
BEFORE 00Z THU AND WILL REMOVE ANY DAYTIME POPS. MORE INSOLATION AND
EXTENT OF CURRENTLY PROGGED THERMAL PROFILES SUGGEST HIGHS IN THE
MID TO UPPER 70S ON WED WITH THE SHOT AT A FEW 80S...ALL OF WHICH
WILL BE RECORD HIGH TERRITORY FOR ALL CLIMATE SITES FOR MARCH 14TH.
FLATTENING RIDGE-RIDING VORT WILL COMBINE WITH LLVL MOISTURE
CONVERGENCE ALONG THE INCOMING FRONT FOR A CHANCE AT SOME NOCTURNAL
SHOWERS AND THUNDERSTORMS WED NIGHT. IF A STORM COULD GET GOING IN
THE LOCAL AREA WED AFTERNOON AND EARLY EVENING AND BECOME SOMEWHAT
ORGANIZED...FCST SOUNDINGS SUGGEST A POTENTIAL FOR A SVR STORM WITH
LARGE HAIL AND DAMAGING WIND...BUT AGAIN A TRIGGER DOES NOT APPEAR
UNTIL LATER THAT NIGHT. ALSO THESE SVR PARAMETERS ARE BEING
ADVERTISED ON THE GFS AND ESPECIALLY THE NAM FCST SOUNDINGS WHICH MAY
AGAIN BE OVERDOING BOUNDARY LAYER MOISTURE.
THURSDAY AND FRIDAY...FLATTENING NON-SENSIBLE FLOW ACRS THE
MIDWEST...UNSEASONABLY MILD REGIME CONTINUES WITH LITTLE FOCUS FOR
ORGANIZED CONVECTION. WILL KEEP LOW POPS FOR WDLY SCTRD SHOWERS OR
THUNDERSTORMS POPPING UP IN THE AFTERNOON CAPES. HIGHS IN THE MID TO
UPPER 70S BOTH DAYS AS MAY ARRIVES EARLY.
SATURDAY THROUGH MONDAY...MOST 12Z RUN MEDIUM RANGE SOLUTIONS AND
LATEST ENSEMBLES SUGGEST PATTERN TO BECOME HIGH AMPLITUDE SINE WAVE
PATTERN ACRS THE CONUS...WITH THE MID MS RVR VALLEY STUCK IN THE
MIDDLE FOR THE REST OF THE EXTENDED. WARM MOIST CONVEYOR UP OFF THE
WESTERN GULF TO CONTINUE TO FLOW UP INTO THE REGION TO FUEL POSSIBLE
SHOWER AND THUNDERSTORM ACTIVITY...BUT AGAIN NO REAL SYNOPTICS SCALE
FEATURES TO SUGGEST MORE ORGANIZATION TO THE CONVECTION EVIDENT AT
THIS TIME THROUGH AT LEAST MON NIGHT...POSSIBLY NOT UNTIL MID NEXT
WEEK AS HIGH AMPLITUDE PATTERN SLOW TO MOVE. THUS WILL KEEP LOW
DIURNAL CHANCES FOR WDLY SCTRD UNORGANIZED CONVECTION IN MAINLY
DAYTIME HEATING WHICH MAY LEAD TO HIGHS IN THE MID TO UPPER 70S
EVERY DAY. ..12..
CLIMATE... RECORD HIGHS FOR MARCH 13TH...
BURLINGTON........77 IN 2007 AND OTHER YEARS
CEDAR RAPIDS......74 IN 2007
DUBUQUE...........71 IN 2007
MOLINE............77 IN 2007
RECORD HIGHS FOR MARCH 14TH...
BURLINGTON........76 IN 1995
CEDAR RAPIDS......75 IN 1995
DUBUQUE...........72 IN 1995
MOLINE............77 IN 1995
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
327 PM CDT SUN MAR 11 2012
...UPDATED SHORT TERM AND LONG TERM SECTIONS...
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 323 PM CDT SUN MAR 11 2012
SYNOPSIS:
ON THE SYNOPTIC SCALE...A SLOW MOVING UPPER LEVEL LOW WAS CENTERED
OVER SOUTHWEST KANSAS DURING THE MID AFTERNOON HOURS. THE RUC MODEL
WAS ANALYZING A -26C COLD CENTER AT 500MB AT THE CENTER OF THE
LOW...AND AROUND -8C AT 700MB. LOW LEVEL MOISTURE HAD WRAPPED ALL
AROUND THE LOW CENTER WHICH PREVENTED THE EROSION OF LOW STRATUS
CLOUDS...KEEPING SURFACE TEMPERATURES IN THE LOWER TO MID 40S
THROUGH THE MID AFTERNOON HOURS. THE HIGH RESOLUTION SHORT TERM
HRRR AND RUC MODELS DID AN EXCELLENT JOB WITH THE TEMPERATURES
TODAY...WITH THE NAM12 PERFORMING POORLY AS IT WAS WARMING THE
SURFACE TOO MUCH WITH CLOUDS ERODING. AS A RESULT...SURFACE-BASED
INSTABILITY DID NOT DEVELOP...AND A MORE STRATIFIED AREA OF RAIN WAS
THE RESULT ACROSS THE SOUTHERN/CENTRAL SECTIONS OF THE DDC FORECAST
AREA.
FORECAST:
WILL BE CARRYING LIKELY TO CATEGORICAL POPS THROUGH THE EARLY
EVENING HOURS ACROSS CENTRAL AND EASTERN SECTIONS OF THE FORECAST
AREA WITH DRYING BEGINNING IN THE WAKE OF THE LOW OVER THE WESTERN
COUNTIES EARLY THIS EVENING. CLEARING IS ACTUALLY STARTING TO TAKE
SHAPE OVER EXTREME SOUTHEAST COLORADO BEHIND THE LOW...AND THIS WILL
ONLY EXPAND EAST INTO SOUTHWEST KANSAS THROUGH THE EVENING. THERE
WILL NOT BE ANY COLD AIR ADVECTION BEHIND THIS LOW WITH TEMPERATURES
ACTUALLY QUITE A BIT WARMER OUTSIDE OF THE LOW AREA (NORTH, WEST,
AND SOUTH). AS FAR AS LOW TEMPERATURES ARE CONCERNED TONIGHT...HAVE
DROPPED THE LOWS A FEW DEGREES OUT WEST GIVEN THE TIMING OF CLOUD
EROSION AND THE ALREADY COOL START TO THE EVENING. RADIATIONAL
COOLING, EVEN WITH 10 KNOTS OF WIND FROM THE WEST, SHOULD DROP
TEMPERATURES DOWN INTO THE LOWER 30S PROBABLY BY MIDNIGHT...THEN
BEGIN TO STABILIZE DURING MUCH OF THE REST OF THE OVERNIGHT HOURS AS
WINDS AVERAGE 10 TO 12 KNOTS FROM THE WEST-SOUTHWEST.
TOMORROW WILL BE A VERY PLEASANT DAY AS HEIGHTS RISE WITH THE
DEPARTURE OF THE LOW NORTHEAST. 850-700MB TEMPERATURES WILL BE
WARMING SUBSTANTIALLY TONIGHT WHICH WILL SET THE STAGE FOR
TEMPERATURES TO RISE RAPIDLY AFTER SUNRISE TOMORROW. IN FACT BY
NOON TOMORROW...TEMPERATURES WILL PROBABLY ALREADY BE WELL INTO THE
MID TO UPPER 60S. HAVE NOT REALLY CHANGED THE PREVIOUS FORECAST AT
ALL REGARDING HIGHS TOMORROW...WITH WIDESPREAD MID TO PERHAPS UPPER
70S EXPECTED. THE LACK OF AN APPRECIABLE PRESSURE GRADIENT/LEESIDE
TROUGH WILL YIELD LIGHT WINDS...LIKELY LESS THAN 10 KNOTS ALL DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 323 PM CDT SUN MAR 11 2012
THE THEME FOR THE EXTENDED PERIOD IS WARM TEMPS (WELL ABOVE NORMAL
TEMPERATURES...20 TO 30 DEGREES ABOVE NORMAL) AND SOME SMALL CHANCES
FOR THUNDERSTORMS LATE IN THE PERIOD.
FOR TUESDAY, THE LEE SURFACE TROUGH WILL STRENGTHEN WITH SW 20 TO 30
KT OF WIND DEVELOPING AT 850 HPA AND AROUND 15 TO 20 MPH
SOUTHWESTERLY DOWNSLOPE WINDS EXPECTED AT THE SFC. THIS WILL RESULT
IN A WELL MIXED ATMOSPHERE WITH RESULTANT GUSTY SOUTHWESTERLY WINDS.
MIXING FROM FORECAST SOUNDINGS IS EXPECTED TO ABOUT 700 HPA. MIX
DOWN TEMPERATURES SUPPORT LOW TO MID 80S DEG F ACROSS MUCH OF SW
KANSAS. DEWPOINTS WILL MIX DOWN TO LOW 20S DEG F TO POSSIBLY UPPER
TEENS DEG F WHICH WILL RESULT IN RH`S CRASHING DOWN TO 10 TO 15
PERCENT. AS A RESULT OF THE AFOREMENTIONED CONCERNS, HAVE ISSUED A
FIRE WEATHER WATCH (RFW) FOR TUESDAY AFTERNOON FOR FAR WESTERN
KANSAS.
BEYOND TUESDAY, A BROAD UPPER AND LOW LEVEL RIDGE ACROSS THE
SOUTHEAST ALONG WITH CONTINUED LEE SURFACE TROUGHING WILL RESULT IN
RETURN FLOW ACROSS THE SOUTHERN/CENTRAL PLAINS. THE DRYLINE SHOULD
BEGIN TO SHARPEN WEDNESDAY WITH UPPER 50S DEG F DEWPOINTS SOUTH OF
THE DRYLINE LOCATED ACROSS SOUTH CENTRAL/SE KANSAS. THE INCREASING
DEWPOINTS WILL LEAD TO MILD LOWS TOWARDS KP28 THROUGH THE REST OF
THE PD.
THE DRYLINE WILL EVENTUALLY MIX WESTWARD AS UPPER LEVEL FLOW BECOMES
MORE MERIDIONAL. THE EXACT DRYLINE POSITION FOR ANY GIVEN DAY IS
UNCERTAIN AT THIS POINT, HOWEVER...THE GENERAL TREND IN THE MODELS
IS TO MIX THE DRYLINE WESTWARD THROUGH THE END OF NEXT WEEK.
THE DRYLINE IN COMBINATION WITH WEAK IMPULSES EMBEDDED IN THE FLOW
ALOFT COULD LEAD TO SOME ISOLATED CONVECTION BEGINNING THURSDAY AND
CONTINUING THROUGH THE WEEKEND. DID NOT DEVIATE FROM THE ALLBLEND
APPROACH AS CONFIDENCE IN STORM INITIATION IS LOW AT THIS POINT. THE
BEST LOCATION FOR SEEING THUNDERSTORM ACTIVITY WILL BE ACROSS SOUTH
CENTRAL KANSAS WHERE BETTER BOUNDARY LAYER MOISTURE/HIGHER CAPE
VALUES IS EXPECTED. CAPPING COULD BE A CONCERN, PARTICULARLY IF YOU
BUY THE WARMER AND DRIER ECMWF.
LOOKING AT WEEK TWO, THE MODELS CONTINUE TO STRUGGLE WITH TIMING OF
THE EJECTION OF THE UPPER LEVEL TROUGH. BY MARCH 19TH, UL FLOW
BECOMES STRONGER AND MORE SOUTHERLY. CAPE VALUES FROM THE ECMWF SHOW
AROUND 2000 J/KG AND 0 TO 6 KM SHEAR INCREASES TO AROUND 50 KT. AT
SOME POINT SEVERE WEATHER COULD BE A SIGNIFICANT CONCERN...
PARTICULARLY AS THE UPPER LEVEL WAVE FINALLY EJECTS OUT ACROSS THE
PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1237 PM CDT SUN MAR 11 2012
FLIGHT CATEGORY WAS IMPROVING TO SLIGHTLY ABOVE IFR THRESHOLD AS
CEILING WAS AVERAGING 1000 TO 1500 ACROSS SOUTHWEST KANSAS
INCLUDING GCK, DDC, AND HYS TERMINALS. THE FLIGHT CATEGORY IS
EXPECTED TO REMAIN MVFR FOR THE REMAINDER OF THE AFTERNOON AS
CEILING STABILIZES AROUND 1500 TO 2000 FEET WITH THE UPPER LEVEL
LOW MOVING OVERHEAD. SOME SCATTERED RAIN SHOWERS WILL REDEVELOP
THIS AFTERNOON ACROSS MUCH OF SOUTHWEST KANSAS AND HAVE GONE WITH
VCSH IN THE GCK, DDC, HYS TAFS FROM ROUGHLY 20Z TO 00Z. AFTER
00Z ONCE THE UPPER LOW MOVES EAST...DRY ADVECTION IS EXPECTED WITH
WINDS BECOMING MORE WESTERLY. AS A RESULT...FLIGHT CATEGORY IS
EXPECTED TO BECOME VFR THIS EVENING WITH WEST-SOUTHWEST WIND
AVERAGING 8 TO 12 KNOTS THROUGH THE NIGHT.
&&
.FIRE WEATHER...
ISSUED AT 403 AM CDT SUN MAR 11 2012
RED FLAG WARNING CRITERIA MAY BE MET TUESDAY BEHIND THE SURFACE DRYLINE
ALONG AND WEST OF A LINE FROM DIGHTON TO GARDEN CITY TO LIBERAL.
MID-LEVEL MOMENTUM IS EXPECTED TO EASILY MIX TO THE SURFACE DURING
THE AFTERNOON WITH WIND GUSTS AS HIGH AS 25-30 KTS FOR A FEW
HOURS, ALONG WITH RELATIVE HUMIDITY VALUES BETWEEN 10 AND 15
PERCENT.
FIRE WEATHER MAY ALSO BE A CONCERN JUST ABOUT EVERY DAY IN FAR
SOUTHWEST KANSAS BEHIND THE DRYLINE FROM WEDNESDAY THROUGH THE
WEEKEND, BUT PARTICULARLY FROM FRIDAY INTO SUNDAY AS SURFACE
PRESSURES FALL IN THE LEE OF THE ROCKIES AND SURFACE WINDS
INCREASE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 34 76 40 83 / 30 0 0 0
GCK 31 77 37 82 / 20 0 0 0
EHA 35 75 35 82 / 10 0 0 0
LBL 33 76 38 81 / 20 0 0 0
HYS 36 77 41 82 / 30 0 0 0
P28 38 78 43 81 / 30 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR KSZ043-044-061>063-074>077-084>087.
&&
$$
UPDATE...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM....SUGDEN
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
623 AM CDT SUN MAR 11 2012
...AVIATION UPDATE...
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
THERE IS A BIT OF UNCERTAINTY IN HOW LOW THE CIGS WILL GO TODAY.
OBS OVER SOUTHERN KS HAVE GENERALLY REMAIN ABOVE 2 KFT WHILE THE
RUC AND NAM PROGS WOULD SUGGEST IFR CIGS. THE RUC ESPECIALLY
LOOKS AGGRESSIVE WITH CIGS COMPARED TO LATEST OBS. THERE IS THE
POTENTIAL FOR SOME IFR CIGS TO MOVE IN BUT THERE IS LITTLE
CONFIDENCE IN TIMING THEM. BECAUSE OF THIS HAVE LEANED MORE
OPTIMISTICALLY TOWARDS THE 1-2 KFT CIGS UNTIL THE IFR CIGS BECOME A
LITTLE MORE APPARENT. STILL FEEL LIKE THERE WILL BE A BREAK IN
PRECIP WITH THE INITIAL WAVE NOW MOVING ACROSS THE AREA BREAKING
UP BY EARLY AFTERNOON. THEN ANOTHER ROUND IS POSSIBLE AS THE UPPER
LOW PASSES OVERHEAD THIS EVENING. TEMPS SHOULD BE WARM ENOUGH FOR
PRECIP TO BE ALL LIQUID.
WOLTERS
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT SUN MAR 11 2012/
TODAY/TONIGHT...WATER VAPOR SHOWS UPPER LOW OVER EASTERN NEW
MEXICO FINALLY ON THE MOVE. AHEAD OF THE LOW...BROAD WARM AIR
ADVECTION WAS ALLOWING FOR AN EXPANSIVE AREA OF SCT SHOWERS FROM
WESTERN/SOUTHERN KANSAS INTO OKLAHOMA. ANTICIPATE ACTIVITY TO THE
SOUTH TO CONTINUE NORTHWARD INTO THE CWA THROUGH THE MORNING
HOURS. MODEL GUIDANCE AND CONSENSUS DATA SUGGEST HEAVIEST
PRECIPITATION TO OCCUR OVER THE EASTERN HALF OF THE CWA BETWEEN
12-16Z THIS MORNING. THEREAFTER THERE MAY BE A BREAK IN THE
PRECIPITATION UNTIL ADDITIONAL ACTIVITY DEVELOPS WITH APPROACH OF
UPPER LOBE OF VORTICITY...MOST LIKELY BEST COVERAGE IN THE EASTERN
SECTIONS OF THE CWA. A THIRD AREA OF PRECIPITATION MAY EVOLVE
UNDERNEATH THE UPPER LOW IN CENTRAL KANSAS DURING THE AFTERNOON
AND MOVE NORTHEAST THROUGH PORTIONS OF THE CWA. THE END RESULT
WILL BE LIKELY TO DEFINITE PROBABILITIES OF MEASURABLE
PRECIPITATION OVER ALL OF THE CWA DURING PERIODS OF THE NEXT 18
HOURS. INSTABILITY WITH THIS SETUP IS VERY MEAGER...AND ONLY A
COUPLE RUMBLES OF THUNDER IS EXPECTED OVER THE CWA. THE LONE
EXCEPTION MAY BE JUST TO THE SOUTHWEST OF THE CWA UNDERNEATH THE
UPPER LOW...WHERE ANY POTENTIAL CLEARING MAY ALLOW FOR STEEPER
LAPSE RATES AND SHALLOW CONVECTION WITH MODEST SHEAR PROFILES.
TEMPERATURES TODAY WILL BE TEMPERED BY THE EXPANSIVE CLOUD COVER
AND BOUTS OF PRECIPITATION...WITH HIGHS IN THE MIDDLE 50S. THE
UPPER LOW WILL QUICKLY DEPART THE CWA TONIGHT...WITH MOST SHOWER
COVERAGE ENDING SHORTLY AFTER MIDNIGHT. LOWS WILL RANGE FROM THE
LOWER 40S WEST TO THE UPPER 40S EAST. MOST CLOUD COVER WILL CLEAR
THE CWA BY SUNRISE MONDAY.
MONDAY THROUGH SATURDAY...A PERSISTENT UPPER PATTERN WITH LARGE
SCALE RIDGING OVER THE CENTRAL CONUS WILL FEATURE THIS ENTIRE
PERIOD. THIS WILL YIELD WELL ABOVE NORMAL TEMPERATURES EACH
DAY...WITH HIGH TEMPERATURES IN THE 70S FOR ALL LOCATIONS IN THE
CWA. A FEW LOCATIONS MAY EVEN REACH OR EXCEED 80 DEGREES ON TUE AND
WED. SLIGHT CHANCES OF THUNDERSTORMS WILL BE POSSIBLE THU-SAT AS THE
CWA RESIDES IN THE WARM SECTOR EAST OF A DRYLINE. WHILE NO
SUBSTANTIAL UPPER FORCING REMAINS EVIDENT IN THIS PERIOD...ANY MINOR
UPPER DISTURBANCE MAY ALLOW FOR A FEW SCT THUNDERSTORMS...ESPECIALLY
DURING PEAK HEATING/INSTABILITY.
BLAIR
&&
.TOP WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
821 PM EDT MON MAR 12 2012
.SYNOPSIS...
ISSUED AT 413 PM EDT MON MAR 12 2012
UNSEASONABLY WARM WEATHER WILL DOMINATE THIS WEEK AS ABOVE NORMAL
500MB HEIGHTS RISE SLOWLY OVERALL. INTO THE UPCOMING WEEKEND...500MB
HEIGHT ANOMALIES OVER THE UPPER LAKES WILL INCREASE FROM 2 TO 2.5
STANDARD DEVIATIONS ABOVE THE LONG TERM AVG FOR MID MARCH. 850MB
TEMPS WILL ALSO BE RUNNING 2-2.5 STANDARD DEVIATIONS ABOVE THE LONG
TERM AVG. OVERALL...IT WILL PROBABLY FEEL MORE LIKE MID MAY THAN MID
MARCH. AT LEAST HERE AT THE OFFICE...SEVERAL HIGH TEMP RECORDS WILL
PROBABLY BE CHALLENGED OVER THE NEXT 7 DAYS. RAIN CHANCES LOOK
LIMITED WITH TROF SETTING UP WELL TO THE W OVER THE WRN CONUS AND A
STRONG RIDGE BUILDING OVER THE ERN CONUS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 413 PM EDT MON MAR 12 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL
LOW SPINNING NE THRU WI. MAIN ARC OF STEADIER PCPN ASSOCIATED WITH
SYSTEM HAS LIFTED N AND E THRU UPPER MI TODAY. SCT PCPN IS OCCURRING
CLOSER TO THE CENTER OF THE MID LEVEL LOW WITH COVERAGE GENERALLY
INCREASING. UNDER APPROACHING COLD POCKET ALOFT ASSOCIATED WITH THE
LOW...A FEW LIGHTNING STRIKES HAVE FINALLY BEEN NOTED OVER CNTRL WI.
AFTER MORNING RAINFALL SATURATED THE LOW-LEVELS AND WITH PCPN LESS
WIDESPREAD THIS AFTN...FOG IS FAIRLY WIDESPREAD WITH SOME AREAS OF
DENSE FOG ALONG LAKE MICHIGAN AND WHERE WINDS ARE UPSLOPING.
WITH MID LEVEL LOW MOVING ACROSS THE AREA THIS EVENING...EXPECT
SCT/NMRS SHRA THIS EVENING. MAINTAINED SLIGHT CHC THUNDER OVER THE
SCNTRL THRU LATE AFTN SINCE SHRA ACTIVITY AROUND LOW APPEARS TO BE
INCREASING IN INTENSITY AND A FEW LIGHTNING STRIKES HAVE RECENTLY
OCCURRED IN CNTRL WI. SHORTWAVE CURRENTLY OVER THE DAKOTAS MAY WORK
TO MAINTAIN BETTER COVERAGE OF SHRA INTO THE LATE EVENING HRS OVER
THE NW PORTION OF THE FCST AREA AS IT TRACKS TO LAKE SUPERIOR.
OTHERWISE...PCPN LOOKS TO END RATHER QUICKLY OVERNIGHT FROM W TO E
AS STRONG DRYING SURGES INTO THE AREA UNDERNEATH UPPER JET.
-SHRA MAY LINGER INTO THE MORNING HRS OVER THE FAR NE FCST AREA.
OTHERWISE...THE STRONG DRYING WILL SET THE STAGE FOR A SUNNY DAY
TUE. DEEP DRY AIRMASS WILL SUPPORT DEEP MIXING...PERHAPS TO
800-750MB. PER FCST SOUNDINGS...THAT WILL YIELD MAX TEMPS AROUND 60F
OVER THE SCNTRL WHERE DOWNSLOPING WRLY WINDS WILL AID WARMING. 50S
SHOULD BE THE RULE ELSEWHERE...WITH LWR 40S ON THE W SIDE OF THE
KEWEENAW AND ALONG LAKE SUPERIOR E OF MUNISING DUE TO WINDS OFF THE
COLD WATERS. GIVEN THE VERY DRY AIRMASS ALOFT THAT CAN BE TAPPED...
LEANED TOWARD DWPTS THAT CAN BE ACHIEVED BY MIXING TUE AFTN.
ALTHOUGH POTENTIAL IS THERE FOR DWPTS TO CRASH TOWARD 0F OVER THE
FAR W AND CNTRL FCST AREA...OPTED TO JUST TREND FCST IN THAT
DIRECTION BY LOWERING GOING FCST SEVERAL DEGREES TO AROUND 10F AS A
START. THIS WILL PUT AFTN RH VALUES DOWN AROUND 15PCT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 413 PM EDT MON MAR 12 2012
THE PERIOD STARTS 00Z WEDNESDAY WITH A LOW PRESSURE SYSTEM ENE OF
THE CWA AND A 500MB RIDGE OF HIGH PRESSURE CENTERED JUST W OF THE
CWA. AT THE SAME TIME...AN UPPER SHORTWAVE TROUGH WILL BE OVER THE
NWRN CONUS/WRN CANADA...WITH A SFC LOW OVER SASK AND SFC TROUGHING
LEEWARD OF THE ROCKIES STRETCHING INTO CO.
THE UPPER RIDGE WILL BE OVER THE CENTER OF THE CWA BY 12Z WED. THE
NW CONUS SHORTWAVE WILL BE NEAR THE NRN SASK/MANITOBA
BORDER...PUSHING THE SFC TROUGH FARTHER E INTO FAR WRN MN. THE
EASTWARD MOVING TROUGH COMBINED WITH A SFC RIDGE JUST E OF THE CWA
WILL RESULT IN INCREASING SW WAA TUE NIGHT INTO WED. 850MB TEMPS
WILL INCREASE FROM 0-5C BY 00Z WED TO 10-13C BY 18Z WED. THIS
RESULTS IN VERY WARM TEMPS FOR WED...WITH HIGHS IN THE MID TO UPPER
60S EXPECTED OVER PORTIONS OF CENTRAL AND WRN UPPER MI...ESPECIALLY
IN DOWNSLOPING AREAS. OVER ERN UPPER MI...HIGHS WILL BE LOWER IN THE
LOW TO MID 50S WITH THE SSW FLOW OFF LAKE MI. THROUGH 00Z THU THINGS
SHOULD STAY DRY AS THE SFC TROUGH MOVES INTO THE FAR WRN CWA. THE
NAM SHOWS SOME CONVECTION POPPING UP BETWEEN 18Z WED AND 00Z THU
OVER THE FAR ERN CWA...BUT THE NAM IS ALSO THE FASTEST WITH MOVING
THE COLD FRONT THROUGH. WITH THE CONSENSUS IDEA...THE COLD FRONT
WILL BE MOVING OUT OF THE SERN CWA BY 00Z FRI. CONSENSUS MODELS ALSO
SHOW CONVECTION OVER CENTRAL AND ERN UPPER MI...BUT MAINLY NEAR LAKE
MI AND OVER FAR ERN UPPER MI AFTER 00Z THU. THE HEAVIER CONVECTION
SHOULD STAY S/SE OF THE CWA AS MODELS SHOW TOO MUCH CAPPING THIS FAR
N...SO SLIGHT CHANCE OF THUNDER WAS RETAINED FROM PREVIOUS FORECAST.
THURSDAY...WITH THE COLD FRONT STALLING JUST SE OF THE CWA...RAIN
WILL REMAIN POSSIBLE NEAR LAKE MI AND E...BUT ONLY CHANCE TO SLIGHT
CHANCE POPS SEEM WARRANTED AT THIS TIME. THURSDAY LOOKS TO BE COOLER
BEHIND THE COLD FRONT WITH 850MB TEMPS AROUND 7C...SO HIGHS WILL BE
IN THE 40S NEAR LAKE SUPERIOR AND NEAR 60 NEAR THE WI BORDER.
FOR THE EXTENDED...MODELS SHOW ANOTHER UPPER DISTURBANCE MOVING N OF
THE CWA THU NIGHT...WITH AN UPPER RIDGE MOVING OVER THE CWA ON FRI.
AFTER FRI...CONFIDENCE IS DECREASED SOME AS MODELS SHOW DIFFERING
SOLUTIONS WITH THE PASSAGE OF A SERIES OF SHORTWAVES THROUGH MONDAY.
HOWEVER...WARM CONDITIONS ARE A CERTAINTY INTO EARLY NEXT WEEK GIVEN
STEADY S/SW FLOW WITH SFC HIGH PRESSURE E AND LOW PRESSURE W. USED
CONSENSUS OF MODELS THROUGH THE EXTENDED WITH SLIGHT CHANCE TO LOW
CHANCE POPS AS MODELS SHOW SOME PRECIP/CONVECTION IN THE WAA REGIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 812 PM EDT MON MAR 12 2012
MID LVL LOW OVER WRN UPR MI WILL LIFT NE OF THE REGION OVERNIGHT.
EXPECT DENSE FOG/VLIFR CONDITIONS AT KSAW TO DISSIPATE EARLY THIS
EVENING AS WINDS SHIFT FROM SSE TO SW BEHIND A SFC TROF PASSAGE. AT
KCMX...VFR CONDITIONS UNDER SW WINDS WILL LOWER TO MVFR AND THEN TO
IFR BY LATE EVENING AS WINDS BCM AN UPSLOPE WRLY DIRECTION.
WITH DOWNSLOPING WINDS AT KIWD...CONDITIONS SHOULD CONTINUE TO BE
MVFR THROUGH THIS EVENING. AS THE LOW MOVES NE OVERNIGHT...EXPECT A
FAIRLY QUICK TRANSITION TO CLEAR SKIES AT ALL TAF SITES UNDER STRONG
DRYING. INTRODUCED LLWS AT KSAW THIS EVENING THROUGH THE OVERNIGHT
HRS AS WINDS ARE EXPECTED TO DECOUPLED THERE. EXPECT WRLY WIND GUSTS
TO APPROACH 30 KTS AT KCMX DURING THE DAY ON TUESDAY .
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 413 PM EDT MON MAR 12 2012
UPPER LEVEL DISTURBANCE AND SURFACE TROF WILL MOVE ENE ACROSS LAKE
SUPERIOR TONIGHT. AHEAD OF THE TROF...SHOWERS AND INCREASINGLY MOIST
AIRMASS WILL SUPPORT SOME FOG...ESPECIALLY OVER WRN AND NRN PORTIONS
OF THE LAKE. FOG SHOULD THIN OUT AFTER TROF PASSES AND WINDS SHIFT
AROUND TO THE W AND INCREASE. WARM AIR ABOVE THE SURFACE WILL LIKELY
KEEP THE MARINE LAYER IN PLACE AND LIMIT THE STRONGER WINDS ALOFT
FROM REACHING THE SURFACE LATE TONIGHT AND TUE. AT THIS TIME...ONLY
EXPECT GUSTS REACHING 30KTS. AFTER TUE...WINDS WILL PROBABLY REMAIN
MOSTLY UNDER 20KTS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. UNSEASONABLY WARM AIRMASS OVER THE UPPER GREAT LAKES WILL
ALSO RESULT IN PERSISTENT MARINE LAYER/STRONG STABILITY OVER THE
LAKE...HELPING TO KEEP WINDS LIGHTER.
&&
.HYDROLOGY...
ISSUED AT 413 PM EDT MON MAR 12 2012
NEAR RECORD TO RECORD SETTING TEMPS YESTERDAY HAS HELPED RIPEN THE
SNOW PACK. RAIN MOVING THROUGH TODAY WILL EXIT THE AREA TONIGHT. THE
BULK OF THE RAIN FELL DURING THE MORNING TO EARLY AFTERNOON HOURS
TODAY...WITH ACCUMULATIONS OF AROUND 0.25 TO 0.70IN. THE
RAIN...COMBINED WITH DEWPOINTS IN THE 40S...WILL HELP TO QUICKEN
SNOWMELT THIS EVENING. AS OF THIS AFTERNOON...LARGER RIVERS ARE
STARTING TO SHOW SOME INCREASED RESPONSE TO THE MELTING AND
PRECIPITATION.
THE RAIN AND SNOW MELT TODAY...COMBINED WITH ABOVE NORMAL
TEMPERATURES THROUGH NEXT WEEKEND WILL LEAD TO A INCREASE IN
RIVER AND STREAM LEVELS OVER THE NEXT SEVERAL DAYS. EXPECT SOME OF
THE RIVERS ACROSS THE AREA TO EXCEED THEIR BANKS BY THE END OF THIS
WEEK. PERSONS LIVING NEAR RIVERS AND STREAMS SHOULD
MONITOR THE LATEST RIVER CONDITIONS AND USE CAUTION IF WALKING
ALONG RIVER BANKS...ESPECIALLY THE CHOCOLAY RIVER...TRAP ROCK
RIVER...AND THE STURGEON RIVER IN WESTERN UPPER MICHIGAN.
ICE JAM WISE...NOT MUCH ICE HAS BEEN NOTED BY OBSERVERS ON THE
FASTER FLOWING RIVERS OVER NRN UPPER MI. BUT THE FORD RIVER...BOTH
AT HYDE AND THE MOUTH AT LK MI...STILL HAS GOOD ICE COVER THAT
LEADS TO SOME CONCERN FOR ICE JAM POTENTIAL WITH THE FASTER RUNOFF.
ALTHOUGH LIMITED SNOW WAS NOTED NEAR LK MI...THERE IS STILL 3-8IN
OF SNOW ...AND NOHRSC ESTIMATED AROUND 1.25IN OF LIQUID...TOWARDS
THE HEADWATERS THAT WILL BE MELTED OVER THE COMING DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...ROLFSON
SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...VOSS
MARINE...ROLFSON
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
754 PM EDT MON MAR 12 2012
.AVIATION...
//DISCUSSION...
AREA OF SHOWERS AND THUNDERSTORMS ANCHORED WITHIN A ZONE OF WEAK BUT
SUFFICIENT INSTABILITY IMMEDIATELY AHEAD OF A COLD FRONT WILL SHIFT
ACROSS SOUTHEAST MICHIGAN THROUGH 06Z. GIVEN THE ORIENTATION AND
EXTRAPOLATING THE UPSTREAM MOVEMENT EASTWARD BRINGS PRECIPITATION
INTO MBS/FNT TO BEGIN TO TAF...PTK 01-02Z...AND THE DETROIT CORRIDOR
03-04Z. ENOUGH CONFIDENCE EXISTS PER LATEST RADAR TRENDS TO SUPPORT
A THUNDER MENTION AT MBS/FNT/PTK...BUT A LACK OF EVIDENCE THUS FAR
WILL PRECLUDE A SPECIFIC MENTION IN DTW. PRECIPITATION LINGERING
POST-FRONTAL MVFR CIGS OVERNIGHT WILL SCATTER BY MID MORNING. WINDS
VEER TO WESTERLY IN THE WAKE OF THE FRONT AND HOLD THROUGH TUESDAY.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH 12Z.
* LOW CONFIDENCE IN THUNDERSTORM COVERAGE THIS EVENING.
&&
.PREV DISCUSSION...ISSUED 351 PM EDT MON MAR 12 2012
SHORT TERM...THIS EVENING AND TONIGHT
STRONG UPPER LOW NOW LOCATED OVER NORTHERN WISCONSIN WILL CONTINUE
TO TRACK TO THE NE ACROSS LAKE SUPERIOR TONIGHT. THE SURFACE
REFLECTION IS RATHER WEAK AS IT REMAINS AN OPEN TROUGH TIED TO A
CLOSED CIRCULATION FURTHER NW OVER MANITOBA. MID LEVEL DRY SLOT IS
WORKING ITS WAY ACROSS SOUTHERN MI PUSHING THE DEEPER MOISTURE FROM
THIS MORNING OFF TO THE EAST. BREAKS IN THE CLOUD COVER HAS ALLOWED
SOME DIURNAL HEATING OVER FAR SW LOWER MI. TEMPS ARE PUSHING THE
UPPER 60S IN THOSE LOCATIONS. IN ADDITION...S/SW WINDS GUSTING UP TO
25 KNOTS HAS BROUGHT IN ABUNDANT SFC MOISTURE WITH DEWPOINTS IN THE
MID 50S ACROSS ALL OF SOUTHERN MI. THE EXCEPTION IS OVER THE EXTREME
EASTERN PORTIONS OF THE CWA WHERE A SE COMPONENT IS STILL HANGING
ON. THIS HELD THE SUB 1000FT CLOUDS FIRMLY UNTIL ABOUT THE LAST WHEN
THEY STARTED TO SCATTER OUT. THUNDERSTORM COMPLEX FROM EARLIER WEST
OF CHICAGO HAS TRACKED NORTH INTO WESTERN MI NORTH OF MUSKEGON. WITH
WIND SHEAR NEARLY UNIDIRECTIONAL FROM THE SW...COMPLEX IS STRUGGLING
TO MAKE ANY EASTWARD PROGRESS.
FOR TONIGHT...THREAT FOR SEVERE WEATHER LATE THIS EVENING REMAINS
CONDITIONAL ON AMOUNT OF SURFACE BASED INSTABILITY WE CAN ACHIEVE.
THERE LOOKS TO BE PLENTY OF WIDESPREAD LIFT SUPPORTING STORM
DEVELOPMENT WITH THE UPPER LEVEL COLD POOL IN PLACE AND THE ENTRANCE
REGION OF A JET STREAK OVER THE REGION. THERE ARE FAVORABLE WIND
PARAMETERS ASSOCIATED WITH THE FRONTAL PASSAGE. BULK SHEAR VALUES
AROUND 40-50 KNOTS...BOTH 0-3KM AND 0-1 KN HELICITY IN EXCESS OF 300
M2/S2. LOOKING AT CAPE VALUES...THOUGH NAM MUCAPE IS ADVERTISED AT
800J/KG...NEITHER THE NAM OR RUC FIND MUCH IN THE WAY OF SFC BASED
CAPE WITH VALUES UP TO 100-200 J/KG WITH HIGHEST AMOUNTS FOR THE
WESTERN PART OF THE CWA. HIRES MODELS SHOW SOME ISOLATED CELLS
TRYING TO GO UP IN ADVANCE OF THE COLD FRONT WITH THE BULK OF THE
SHOWERS/STORMS OCCURRING THE FRONT ITSELF MAINLY FROM
23Z-05Z...WORKING SOUTH FROM MBS TO DTW. LOOKS LIKE SMALL HAIL AND
WIND GUSTS TO 50MPH WILL BE THE MOST LIKELY RESULTS OF THESE
STORMS...ALTHOUGH IF WE CAN GET MORE SFC BASED INSTABILITY SEVERE
STORMS WILL NOT BE OUT OF THE QUESTION.
LONG TERM...
THE WARM PATTERN LOOKS TO STICKING AROUND FOR THE EXTENDED
PERIOD...WITH POTENTIAL PSEUDO OMEGA BLOCKING PATTERN SETTING UP
LATE IN THE WEEKEND/EARLY NEXT WEEK.
CONSOLIDATING UPPER WAVES TAKES PLACE OVER ONTARIO TOMORROW...WITH
SHORTWAVE TROUGH AXIS AND SLIGHT HEIGHT FALLS TAKING PLACE LATE IN
THE DAY. STILL...WITH FAVORABLE WESTERLY WINDS AND THE TEMP GRADIENT
ADVERTISED (925 MB TEMPS OF 8 C NORTH TO 11 C SOUTH)...LOOKING AT
UPPER 50S NORTH TO MID 60S SOUTH WITH PLENTY OF SUNSHINE.
SURFACE RIDGE AXIS ARRIVING TOMORROW EVENING SHOULD ALLOW FOR
FAVORABLE RADIATING CONDITIONS...BUT WE ALREADY HAVE MODEST LOW
LEVEL WARM ADVECTION RETURNING BY SUNRISE WEDNESDAY. GUIDANCE TEMPS
IN THE 30S APPEAR REASONABLE.
A DRY WARM FRONT EXPECTED TO PUSH NORTH OF SOUTHERN LOWER MICHIGAN
DURING WEDNESDAY AS UPPER LEVEL RIDGE BUILDS OVERHEAD...PUSHING
TEMPS TO 70 DEGREES OR BETTER BASED ON FORECASTED 925 MB TEMPS OF
+15 TO +16 C. THE EXCEPTION WILL BE ACROSS THUMB REGION WHERE FRONT
WILL PROBABLY NOT CLEAR BY DAYS END...WITH BACKED SOUTHEAST FLOW
COMING OFF COOL WATERS OF SOUTHERN LAKE HURON.
DEEP SOUTHWEST FLOW OVER THE CENTRAL CONUS THURSDAY/FRIDAY...WITH
POTENTIAL UPPER LEVEL PV FILAMENT ROLLING THROUGH ON THURSDAY...PER
12Z GFS...TO TRIGGER SHOWERS AND POSSIBLE THUNDERSTORMS...AS
RESPECTABLE SURGE IN MOISTURE TAKES PLACE. CLOUDS AND CONVECTIVE
ACTIVITY COULD BE ENOUGH TO KEEP TEMPS STUCK IN THE UPPER 60S
DESPITE THE VERY MILD START TO THE DAY. THE 12Z EUROPEAN OFFERS A
DIFFERENT SOLUTION AND SUGGESTS THE SHORTWAVE/TROUGH COMING OUT OF
THE NORTHERN PLAINS WILL BE STRONGER...MOVING THROUGH ON FRIDAY.
THIS WOULD TRANSLATE TO A WARM DAY ON THURSDAY (70S) AND BETTER
CHANCE OF SHOWERS ON FRIDAY. THE CANADIAN IS MORE IN LINE WITH THE
GFS...SO WILL NOT MAKE A BIG PUSH TO EXTENDED GRIDS MUCH.
MEDIUM RANGE MODELS STILL FORECASTING AMPLIFIED PATTERN FOR THE
WEEKEND INTO EARLY NEXT WEEK...WITH LONGWAVE TROUGH OUT WEST AND
UPPER LEVEL RIDGE BUILDING NEAR THE GREAT LAKES REGION. ALMOST
SUMMER LIKE RIDGE (582-586 DAM AT 500 MB)...AND TEMPS APPROACHING 80
DEGREES IS NOT OUT OF THE QUESTION AS WE GET TO TUESDAY AS 1000-500
MB THICKNESSES CLIMB TOWARD 564 DAM. LAKE BREEZES WOULD LIKELY BE
COMING INTO PLAY HOWEVER AND WILL NEED TO REMAIN MORE CONSERVATIVE
THAT FAR OUT...ESPECIALLY WITH THE EUROPEAN PROFILES A BIT COOLER.
MARINE...
OUTSIDE OF A FEW POSSIBLE THUNDERSTORMS THIS EVENING...MARINE
CONDITIONS ARE EXPECTED TO REMAIN QUIET. UNUSUALLY MILD AIR IN PLACE
FOR EARLY MARCH WILL LEAD TO STABLE STABLE LOW LEVEL PROFILES OVER
THE GREAT LAKES. THIS WILL MINIMIZE THE GUST POTENTIAL TO AROUND 20
KNOTS OVER THE NEXT SEVERAL DAYS. THOSE STRONGER WINDS LOOKED TO BE
CONFINED TO THE NORTH THIRD OF LAKE HURON TOMORROW...AS CHANNELING
OCCURS WITH WESTERLY FLOW. THE NEXT CHANCE OF THUNDERSTORMS RETURNS
ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....99
SHORT TERM...DRK
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS
ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS JACKSON MS
319 PM CDT SUN MAR 11 2012
.SHORT TERM...
MAIN FOCUS IN SHORT TERM IS POTENTIAL FOR STRONG/SEVERE THUNDERSTORMS
TONIGHT AND MONDAY AND LOCALLY HEAVY RAIN IN WESTERN AREAS TONIGHT.
FIRST OFF FOR TONIGHT...CONTINUE TO MONITOR CONVECTIVE BAND RUNNING
FROM KTXK SSW TO NEAR KGLS. MOST INTENSE BAND IS EMBEDDED WITHIN A
LARGE PRECIP SHIELD WHICH IS GENERALLY NOT PARTICULARLY FAVORABLE FOR
SEVERE WX. HOWEVER...AREAS WITHIN THE BAND HAVE EXHIBITED BOW/LEWP
TYPE STRUCTURES...PARTICULARLY FEATURE OVER EC TX NE OF KLFK WHICH
HAS SHOWN PERSISTENT ROTATION/MARC. BASED ON SETUP OF STRENGTHENING
WIND FIELDS AHEAD OF EJECTING UPPER LOW AND INCREASING SFC BASED
INSTABILITY THIS AFTERNOON OVER LA...EXPECT ACTIVITY TO CONTINUE TO
SHOW BOW/LEWP CHARACTERSTICS WITH CORRESPONDING RISK OF SPORADIC
DAMAGING WIND GUSTS AND POSSIBLY A TORNADO. BEST RISK WILL LIKELY BE
OVER NE LA PARISHES WHICH SHOULD HAVE BEST OVERLAY BETWEEN STRONGEST
SBCAPE...CURRENTLY 1000-1500 J/KG S OF HWY 84...AND MAX IN WIND SHEAR
PULLING THROUGH AR. EXTRAPOLATION AND HRRR CONTINUE TO SHOW ACTIVITY
REACHING FAR WRN AREAS 22Z-00Z. THREAT OF SEVERE WX SHOULD DIMINISH
AFTER 03Z AS UPPER LOW PULLS AWAY AND FORCING DIMINISHES.
AS FAR AS HEAVY RAINFALL...AS MENTIONED IN HPC QPF DISCUSSION EXPECT
THIS CONVECTION TO BE EFFICIENT AT PRODUCING RAINFALL GIVEN TALL
CAPES AND PW VALUES AROUND 200 PCT OF NORMAL. HIGH RES MODELS
GENERALLY SHOW WIDESPREAD 0.5 TO 1 INCH TOTALS OVERNIGHT GENERALLY NW
OF THE NATCHEZ TRACE...WITH LOCALIZED AMOUNTS OF 1-3"...WHICH SEEMS
REASONABLE. HAVE SOME CONCERN ABOUT THE POSSIBILITY OF SOMEWHERE IN
THE WESTERN PART OF THE AREA GETTING SOME LOCALIZED EVEN HEAVIER
TOTALS GIVEN THAT THE UPPER TROUGH WILL BE PULLING AWAY AND MCS IS
LIKELY TO SLOW DOWN OR EVEN STALL. THIS IS HINTED AT IN SOME OF THE
MODEL GUIDANCE WITH CORFIDI VECTORS GET VERY SMALL...AND HIGH RES NMM
MODEL SHOWS AREA OF 5+ INCHES OF RAIN IN PARTS OF THE LOWER DELTA.
NOT READY TO JUMP ON THOSE KIND OF LOCALIZED AMOUNTS...ESPECIALLY AS
850 MB FLOW WILL BE WEAKENING AND LOW LEVEL MOISTURE VALUES ARE NOT
EXTREME. HOWEVER THIS WILL BE SOMETHING LATER SHIFTS WILL NEED TO
KEEP AN EYE ON.
AS FAR AS MONDAY...CONVECTION WILL LIKELY BE ONGOING IN A BAND
SOMEWHERE ALONG THE NATCHEZ TRACE IN THE MORNING. AS DAYTIME HEATING
CAUSES DESTABILIZATION...EXPECT ACTIVITY TO GRADUALLY INCREASE IN
COVERAGE AND INTENSITY INTO THE ATMOSPHERE. WHILE MAIN 500 MB TROUGH
WILL CONTINUE TO PULL AWAY...AREA WILL REMAIN IN RIGHT ENTRANCE
REGION OF 250 MB JET...AND INCREASE IN MID LEVEL FLOW AND SUBTLE
HEIGHT FALLS INDICATE A WEAK DISTURBANCE MAY MOVE THROUGH TO HELP
CONVECTION REENERGIZE IN THE AFTERNOON. IF ROBUST CONVECTION CAN GET
GOING...EXPECT AT LEAST AN ISOLATED SEVERE RISK GIVEN MLCAPE VALUES
AROUND 2000 J/KG AND GOOD DCAPE VALUES. COULD SEE SOME GOOD HAIL
GIVEN COLD TEMPERATURES ALOFT AND LARGE CAPE VALUES ABOVE FREEZING
LEVEL. WOULD EXPECT BEST CONVECTIVE RISK TO BE ALONG/SE OF TRACE
WHERE BEST UPPER SUPPORT AND LOW LEVEL MOISTURE CONVERGENCE AHEAD OF
OVERNIGHT CONVECTION SHOULD EXIST.
CONVECTION SHOULD DECREASE MONDAY NIGHT WITH JUST SOME WIDELY
SCATTERED DIURNAL CONVECTION EXPECTED TUESDAY. WILL HAVE TO WATCH FOR
FOG POTENTIAL MONDAY NIGHT IF SFC FLOW CAN FULLY DECOUPLE. MAV MOS IS
HINTING AT VERY LOW CIG/VSBYS BUT DID NOT WANT TO JUMP ON THAT YET
GIVEN DECENT PRESSURE GRADIENT FORECAST BY MODELS.
.LONG TERM...
PATTERN OVER AREA FOR LATTER PART OF THE WEEK WILL BE MORE LIKE LATE
SPRING WITH UPPER RIDGING PROVIDING UNSEASONABLY WARM CONDITIONS.
MAIN PRECIP THREAT WILL BE ASSOCIATED WITH ISOLATED DIURNAL
CONVECTION. ONE FLY IN THE OINTMENT COULD COME AROUND MIDWEEK WHEN
GFS/EC IMPLY THAT OLD BOUNDARY COULD GET REENERGIZED INTO SUPPORTING
AN MCS ALONG IT NW OF US WHICH WOULD ROLL ESE IN GRADIENT OF THETA-E.
THIS WILL HAVE TO BE WATCHED BUT FOR NOW CURRENT FORECAST HANDLES
OVERALL SITUATION QUITE WELL SO NO CHANGES WERE MADE TO FORECAST
BEYOND TUESDAY NIGHT.
&&
.AVIATION...
GUSTY SE SFC WINDS WILL PERSIST THRU THE AFTN AND INTO THIS EVENING
BEFORE THE GUSTS TAPER OFF NEAR/AFTER 01Z...WITH SUSTAINED SOUTHERLY
WINDS NEAR 10KTS XPCTD THRU THE NIGHT. CIG WILL REMAIN MVFR FOR A
GOOD PORTION OF THE ARKLAMISS TODAY AS LOW LEVEL MOISTURE IS PULLED
NORTH IN WAKE OF A WARM FRONT MOVING NORTH. A TREND TOWARD IFR CIG
WILL BEGIN AFTER 03Z TONIGHT HOWEVER SFC VSBYS WILL REMAIN VFR THRU
THE NIGHT THANKS TO THE WINDS. +SHRA/TSRA ASSOCIATED WITH A WEAK
BOUNDARY OVER NE TX WILL BEGIN TO IMPACT NE LA/SE AR AND THE DELTA
REGION OF MS AROUND 00Z THIS EVENING. SOME OF THIS ACTIVITY COULD
CONTAIN SEVERE TSRA HOWEVER THIS SHOULD COME TO AN END AFTER 06Z.
LINGERING SHRA WILL CONTINUE INTO TONIGHT PRIMARILY N OF I-20. /BK/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 63 79 60 79 / 77 46 25 22
MERIDIAN 61 81 59 80 / 54 60 39 31
VICKSBURG 64 79 59 79 / 84 39 14 15
HATTIESBURG 64 82 62 82 / 27 53 33 37
NATCHEZ 62 78 60 78 / 74 33 15 16
GREENVILLE 61 79 59 80 / 99 39 10 11
GREENWOOD 62 79 59 80 / 92 54 19 14
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AEG/BK
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1255 PM CDT SUN MAR 11 2012
.UPDATE...
ADJUSTED GRIDS AND RAN ZONE UPDATE TO REDUCE POPS MOST AREAS THIS
AFTERNOON. SHOWERS HAVE GENERALLY BEEN DECREASING IN COVERAGE OVER
THE LAST 2 HOURS...AND WHILE SOME SCATTERED SHRA CAN STILL BE
EXPECTED ESPECIALLY IN WESTERN AND NORTHERN AREAS...COVERAGE DOES
NOT APPEAR TO WARRANT POPS AS HIGH AS WHAT WE HAD GOING. RADAR
TRENDS AND LATEST HIGH RESOLUTION MODELS CONTINUE TO SUPPORT BAND OF
STRONG TO LOCALLY SEVERE STORMS MOVING INTO OUR WESTERN AREAS IN THE
22Z TO 00Z TIMEFRAME. 15Z HRRR AND 12Z HIGHRES NMM-WRF IN PARTICULAR
ARE RELATIVELY AGGRESSIVE IN SHOWING WELL DEFINED BOWING SEGMENTS
AND SOLID UPDRAFT HELICITY VALUES AS ACTIVITY MOVES INTO NE LA AND
SE AR. CURRENT HWO AND GRAPHICASTS SEEM TO HANDLE THIS SCENARIO WELL.
&&
.AVIATION...
GUSTY SE SFC WINDS WILL PERSIST THRU THE AFTN AND INTO THIS EVENING
BEFORE THE GUSTS TAPER OFF NEAR/AFTER 01Z...WITH SUSTAINED SOUTHERLY
WINDS NEAR 10KTS XPCTD THRU THE NIGHT. CIG WILL REMAIN MVFR FOR A
GOOD PORTION OF THE ARKLAMISS TODAY AS LOW LEVEL MOISTURE IS PULLED
NORTH IN WAKE OF A WARM FRONT MOVING NORTH. A TREND TOWARD IFR CIG
WILL BEGIN AFTER 03Z TONIGHT HOWEVER SFC VSBYS WILL REMAIN VFR THRU
THE NIGHT THANKS TO THE WINDS. +SHRA/TSRA ASSOCIATED WITH A WEAK
BOUNDARY OVER NE TX WILL BEGIN TO IMPACT NE LA/SE AR AND THE DELTA
REGION OF MS AROUND 00Z THIS EVENING. SOME OF THIS ACTIVITY COULD
CONTAIN SEVERE TSRA HOWEVER THIS SHOULD COME TO AN END AFTER 06Z.
LINGERING SHRA WILL CONTINUE INTO TONIGHT PRIMARILY N OF I-20. /BK/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AG/BK
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
945 AM CDT SUN MAR 11 2012
.UPDATE...INITIAL BATCH OF PRECIPITATION NOW PASSING THROUGH WESTERN
MS PER LATEST RADAR IMAGERY. THIS ACTIVITY SHOULD CONTINUE TO LIFT
NE ACROSS N/W AREAS THIS MORNING...AND THIS IS HANDLED WELL IN
CURRENT FORECAST. AFTER THIS PASSES THROUGH...INITIAL VISIBLE
SATELLITE IMAGES SHOW SOME BREAKS IN CLOUDS ACROSS LA/SOUTHERN MS
WHICH SHOULD ALLOW SOME FILTERED PEEKS OF SUN AT TIMES ESPECIALLY
ACROSS S AND W AREAS TODAY. THIS SHOULD ALLOW TEMPS TO REACH
FORECAST MAXES IN THE LOW/MID 70S...THOUGH WILL HAVE TO KEEP AN EYE
ON THINGS IN NORTHERN AREAS WHERE MORE CLOUDS AND MORE EASTERLY LOW
LEVEL FLOW COULD KEEP THINGS A BIT COOLER THAN CURRENTLY FORECAST.
AS FAR LATEST THINKING FOR CONVECTIVE RISK OVER WESTERN AREAS WHERE
SPC HAS OUTLOOKED A SLIGHT RISK OF SEVERE...RADAR/SATELLITE
INDICATES THAT CONVECTIVE BAND IS CURRENTLY INCREASING OVER EASTERN
TX. MODELS SUGGEST THIS ACTIVITY WILL GRADUALLY BECOME MORE ROBUST
AS INSTABILITY INCREASES DURING THE DAY AND FORCING INTENSIFIES AS
UPPER LOW CURRENTLY OVER OVER TX PANHANDLE BEGINS TO EJECT OUT TO
THE NE. SFC DEWPOINTS ARE CURRENTLY RUNNING IN THE 50S/LOWER 60S
ACROSS LA...BUT 12Z RAOBS INDICATE THAT BETTER MOISTURE/INSTABILITY
EXISTS JUST ABOVE A RELATIVELY SHALLOW LAYER OF COOLER AIR. EXPECT
THAT EVEN WITH WIDESPREAD CLOUDS...INCREASING LOW LEVEL FLOW AND
SOME FILTERED SUN WILL ALLOW MUCH OF THIS LOW LEVEL COOLER AIR TO BE
MIXED OUT AND THAT CONVECTION OVER E TX WILL GRADUALLY BECOME MORE
SFC BASED AS IT MOVES INTO LA. LATEST 11Z HRRR INDICATES BAND OF
STRONG CONVECTION WITH EMBEDDED SUPERCELLS...UPDRAFT HELCITIY VALUES
IN EXCESS OF 125 M2/S2...WILL MOVE INTO OUR WESTERN AREAS AROUND
00Z. THIS SEEMS REASONABLE ASSUMING THAT INSTABILITY CAN EVOLVE IN
MANNER SUGGESTED BY HIGH RES MODELS AND 12Z NAM/00Z EC. GIVEN QUITE
FAVORABLE LOOKING SHEAR PROFILES WITH STRONGLY TURNING CLOCKWISE
HODOGRAPHS...0-1 KM SREH VALUES IN EXCESS OF 300 M2/S2...WOULD
EXPECT RISK OF A FEW SEVERE STORMS WITH DAMAGING WINDS AND POSSIBLY
A COUPLE OF TORNADOES WITH THIS ACTIVITY. PRIMARY RISK OF SEVERE IS
FOCUSED ALONG W OF MS RIVER AND ESPECIALLY NW OF A DELHI LA TO
INDIANOLA MS LINE WHERE BEST FORCING FROM EJECTING UPPER SYSTEM WILL
EXIST ALONG WITH MOST FAVORABLE OVERLAY OF SHEAR/INSTABILITY. MAIN
WINDOW OF SEVERE DEFINITELY LOOKS TO EXIST IN 00Z-06Z PERIOD WHEN
UPPER FORCING IS MAXIMIZED...THIS IS ALSO SUPPORTED BY LOCAL WRF
WHICH HAS MAIN AREA OF STRONG STORMS PRODUCING DECENT WIND GUSTS
MOVING THROUGH DELTA DURING THIS TIME PERIOD. WE HAVE TWEAKED THE
GRAPHICASTS TO MATCH ALL THIS THINKING. /08/
&&
.PREV DISCUSSION... /ISSUED 420 AM CDT SUN MAR 11 2012/
.SHORT TERM...TODAY THROUGH MONDAY NIGHT...JUST A QUICK HEADS UP
THAT IF YOU ARE READING THIS AND DO NOT REALIZE THE TIME HAS CHANGED
THEN YOU MIGHT BE AN HOUR LATE FOR SOMETHING.
IMPRESSIVE AND PHASING CLOSED LOW NOW CENTERED OVER THE PANHANDLES
OF TEXAS AND OKLAHOMA WILL BE MOVING NORTHEAST AT AN INCREASING PACE
THROUGH TONIGHT...WITH THE SOUTHEASTERN EXTENT OF UPPER FORCING
AFFECTING THE LOWER MS VALLEY. SOMEWHAT COMPLEX FRONTAL EVOLUTION
WILL TAKE PLACE IN OUR VICINITY THROUGH THIS TIME IN RESPONSE.
INITIALLY...PREVIOUSLY STALLED FRONT ACROSS THE NORTHERN GULF OF
MEXICO WILL BE MOVING NORTH ACROSS THE REGION THROUGH THE DAY AS A
WARM FRONT...BUT PERHAPS NOT CLEARING THE GOLDEN TRIANGLE REGION
UNTIL THIS EVENING. PRECIPITATION POTENTIAL WITH THIS WARM FRONTAL
PASSAGE DID NOT LOOK OVERLY IMPRESSIVE ON PREVIOUS EXAMINATION BUT
LATEST MODEL GUIDANCE AND CURRENT REGIONAL RADARS GIVE THE
IMPRESSION MANY AREAS COULD SEE MEASURABLE PRECIP THROUGH EARLY
AFTERNOON. THINKING IS STILL THAT THIS INITIAL SHOWERY STUFF SHOULD
NOT STICK AROUND TOO LONG AND WILL BE GENERALLY LIGHT.
BY MID TO LATE AFTERNOON MOST OF THE REGION SHOULD BE IN THE WARM
SECTOR WITH RATHER GUSTY SOUTH TO SOUTHEASTERLY WINDS AND MAYBE A
FEW PATCHES OF SUNSHINE. A FEW SHOWERS WILL STILL BE ABOUT WITH
INCREASING INSTABILITY MEANING A STRAY THUNDERSTORMS IS NOT OUT OF
THE QUESTION EITHER (ALTHOUGH THE LATTER MAINLY APPLIES TO LOCATIONS
ALONG AND WEST OF THE HIGHWAY 49 CORRIDOR). BUT SOMEONE VIEWING
REGIONAL RADARS AT LATE AFTERNOON WILL PROBABLY FIND VIGOROUS SHOWER
AND STORM ACTIVITY LINING UP JUST WEST OF THE REGION ALONG A WEAK
COLD FRONT PRESSING IN FROM THE WEST.
THE STORM PREDICTION CENTER HAS ASSESSED A SLIGHT RISK OF SEVERE
WEATHER WITH THE ACTIVITY ALONG THIS JUST-MENTIONED FRONTAL ZONE
THIS AFTERNOON AND INTO THIS EVENING. THEIR SLIGHT RISK BASICALLY
COVERS OUR NW COUNTIES ALONG THE RIVER AND ALL OUR AR COUNTIES AND
NE LA PARISHES WITH DAMAGING WINDS AND HAIL TO QUARTER SIZE BEING
THE MAIN RISKS. AN EXCEPTION TO TO THE LATTER STATEMENT COULD BE
ACROSS SE AR AND MOREHOUSE PARISH WHERE THE RISK OF A TORNADO IS
HIGHER DUE TO THERE RESPECTIVE PROXIMITY TO EXPECTED
INSTABILITY/SHEAR MAXIMUM. THE SPC`S ASSESSMENT SEEMS GOOD FROM OUR
VIEWPOINT BECAUSE WE ARE EXPECTING THE VIGOROUS STORMS ASSOCIATED
WITH THE FRONT TO BE MOVING INTO OUR FAR WESTERN AREAS IN THE EARLY
EVENING WITH WANING INSTABILITY MUCH AFTER THAT POINT REALLY RAMPING
DOWN SEVERE RISK FURTHER EAST. WILL UPDATE THE HWO TO REFINE SEVERE
RISKS...LOCATION AND TIMING.
AS MENTIONED IN PREVIOUS FORECASTS...HEAVY DOWNPOURS LOOK TO OCCUR
OVERNIGHT WITH ACTIVITY MOVING IN FROM THE WEST AND THE EXPECTATION
OF SLOW MOVEMENT OF THE AXIS OF SHOWERS AND STORMS MEANS THAT SOME
AREAS COULD EXPERIENCE REPEATED HEAVY DOWNPOURS. ISOLATED RAINFALL
TOTALS (PARTICULARLY IN THE UPPER ARKLAMISS DELTA) BY DAYBREAK
MONDAY OF UP TO 2 INCHES ARE POSSIBLE BUT THIS SHOULD NOT CAUSE ANY
MAJOR FLOODING PROBLEMS. FURTHER EAST IN THE FORECAST AREA
ANTICIPATING AT LEAST SHOWERY ACTIVITY WITH SOME EMBEDDED STORMS TO
PICK UP AS THE NIGHT GOES ON AND BETTER GULF MOISTURE SURGES NORTH.
THE WEAK FRONT MOVING IN TONIGHT WILL DRAPE FROM SW TO NE ACROSS THE
UPPER DELTA BY DAYBREAK MONDAY AND WILL BE BASICALLY STALLED AND
DILUTING...ALTHOUGH A DRYING AXIS ABOVE THE GROUND WILL STILL BE
PUSHING EAST AND LEAVING THE STALLED SURFACE BOUNDARY BEHIND.
MODERATE UPPER LEVEL FLOW WILL REMAIN FROM THE SOUTHWEST AND WILL BE
SOMEWHAT PERTURBED...BUT THERE WILL BE NO BIG SHORTWAVES TO PROVIDE
LIFT. HOWEVER...LATEST MODEL GUIDANCE GIVES CONFIDENCE THERE WILL BE
JUST ENOUGH LIFT TO ENSURE TRIAD OF MOISTURE/LIFT/INSTABILITY IS MET
AND SHOWERS AND THUNDERSTORM FORM (ESPECIALLY SOUTHEAST OF THE
NATCHEZ TRACE) AS WE GO THROUGH THE MIDDAY AND AFTERNOON HOURS. PEAK
MEAN LAYER CAPE VALUES WILL EASILY RANGE FROM 1000-1500 J/KG IN MOST
OF THE REGION WITH DEEP LAYER SHEAR RUNNING 10 KTS OR SO BELOW 40 KT
THRESHOLD FOR FULL STORM ORGANIZATION. THIS ASSESSMENT SUGGESTS AT
LEAST A STRONG STORM IS POSSIBLE ANYWHERE...BUT ANY ISOLATED SEVERE
ACTIVITY WILL PROBABLY BE MAINLY LIMITED TO THE VICINITY OF THE
NATCHEZ TRACE CORRIDOR IN MS WHERE SREF SUGGESTS PEAK MLCAPE VALUES
EXCEEDING 1500 J/KG IS A DECENT POSSIBILITY. SEVERE STORM RISKS FOR
MONDAY SHOULD BE LIMITED TO HAIL AND WIND GUSTS. OH YEA...IT WILL
ALSO BE QUITE WARM ON MONDAY DESPITE THE CLOUDS WITH SOME FOG
POSSIBLE OVERNIGHT AFTER MOST OF THE ACTIVITY DIMINISHES IN THE
EVENING. /BB/
.LONG TERM...TUESDAY THROUGH LATE WEEKEND....ABOVE AVERAGE
TEMPERATURES EXPECTED THROUGH LONG TERM WITH DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORMS MOST AFTERNOONS/EARLY EVENINGS.
SYNOPTIC PATTERN BY EARLY/MID WEEK WILL FEATURE AN EXITING TROUGH
ACROSS THE EASTERN CANADIAN MARITIME WITH SUBTROPICAL RIDGING TAKING
HOLD OVER THE SE CONUS. THIS SUBTROPICAL RIDGING...ALONG WITH IN
SITU LOW-LVL MOISTURE CHARACTERIZED BY SFC DEWPOINTS VARYING BETWEEN
THE UPPER 50S TO MID 60S THROUGH OUT THE WEEK...WILL KEEP AREA QUITE
WARM. MIN LOW TEMPS THROUGH PERIOD WILL BE ~10-14 DEGREES F ABOVE
NORMAL AND HIGHS BEING ROUGHLY 10 DEGREES F ABOVE NORMAL FOR THIS
TIME OF YEAR. THE LONG TERM PATTERN IS MORE REMINISCENT OF THE MONTH
OF MAY OPPOSED TO MARCH.
DUE TO INCREASING H7-H5 HEIGHTS ALONG WITH SLIGHT RIDGING TO ZONAL
SW FLOW ACROSS CENTRAL CONUS...MUCH OF THE JET STREAM ENERGY WILL BE
FAR REMOVED TO THE NORTH...LEAVING LITTLE...IF ANY DYNAMIC LIFTING
TO EFFECT THE REGION. HOWEVER...WITH ELEVATED SFC DEWPOINTS IN THE
LOW 60S AND DAYTIME TEMPS EXPECTED TO RISE INTO THE U70S/L80S...
MLCAPES OF 1500-2000 J/KG COULD BE REACHED DURING THE PEAK HEATING
HOURS THROUGH THE LONG TERM PERIOD. WHILE SUBTLE DIFFERENCES WILL
EXIST EACH DAY THAT WILL DETERMINE OVERALL THUNDERSTORM COVERAGE AND
POTENCY...(I.E. CAPPING AND LOWER THETA-E POCKETS ENTRAINED WITHIN
SE FLOW FROM GOM VS. SUBTLE S/WV`S EMBEDDED WITHIN SW H5 FLOW) EACH
DAY THROUGH SUNDAY APPEARS TO HAVE AT LEAST ISOLATED TO SCATTERED
SHOWER/TSTORM COVERAGE. IT COULD ALSO BE CONCEIVABLE THAT WITH THE
RIGHT SUPPORT...SOME STORMS COULD BECOME STRONG AS THE H5-H3
TEMPERATURE PROFILE STILL REMAINS COOL AIDING IN BETTER LAPSE RATES.
AN OVERALL PATTERN CHANGE LOOKS TO OCCUR THROUGH THE LATE WEEKEND AS
A LARGE...HIGHLY AMPLIFIED TROUGH BEGINS TO MIGRATE ACROSS THE
WESTERN CONUS. THIS SYSTEM MAY BE ABLE TO SWING A FRONT THROUGH
THROUGH THE MID PORTIONS OF NEXT WEEK (10-13 DAY TIME FRAME).
FOR FORECAST SPECIFICS...MIN LOW TEMPS WERE BUMPED UP 3-6 DEGREES
THROUGH PERIOD OVER MEXMOS GUIDANCE AS BOTH GFS/EC WERE IN
AGREEMENT OF HIGHER MOISTURE INFLUX. USED RAW GFS DEWPOINTS WITH
SOME ADJUSTMENTS AS MOS VALUES APPEARED TO LOW. POPS WERE
GENERALLY ACCEPTED BUT TWEAKED A BIT ON FRIDAY AS LARGER DRY POCKET
PER GFS/EC LOOKS TO ROTATE AROUND THE HIGH PRESSURE GYRE. GIVEN LACK
OF ANY LIFT OTHER THAN THERMODYNAMIC BUOYANCY DURING PEAK HEATING
HOURS AND SOME SUSTAINING OUTFLOW COLLISIONS...POPS WERE CUT BACK
DURING MOST OF THE OVERNIGHT PERIODS AS STABILIZATION OCCURS. /ALLEN/
&&
.AVIATION...PATCHY SUB-VFR (MAINLY MVFR) FLIGHT CATS WILL BUILD IN
FROM SW TO NE THIS MORNING DUE TO CEILINGS AS A WARM FRONT COMES UP
FROM THE SOUTH. SHOWERS ASSOCIATED WITH THIS FRONT THROUGH EARLY
AFTERNOON WILL BE MOST PREVALENT NORTHWEST OF THE NATCHEZ
TRACE...BUT SHOULD GENERALLY NOT BE HEAVY. WINDS WILL BECOME
CONSISTENTLY FROM THE SOUTHEAST AFTER THE WARM FRONT PASSES AND WILL
BE GUSTY BY AFTERNOON. EXPECT A WEAK APPROACHING COLD FRONT TO BRING
MORE VIGOROUS SHOWERS AND STORMS TO THE AXIS OF THE MS RIVER BY MID
EVENING WITH AT LEAST SOME OF THIS ACTIVITY BUILDING FURTHER EAST
OVERNIGHT. OTHERWISE...EXPECT MVFR TO IFR FLIGHT CATS LATER TONIGHT
DUE MAINLY TO CEILING RESTRICTIONS. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 74 62 80 61 / 68 77 57 25
MERIDIAN 72 60 81 60 / 50 54 67 39
VICKSBURG 76 63 80 61 / 80 82 43 14
HATTIESBURG 73 62 81 63 / 31 27 61 33
NATCHEZ 75 63 78 63 / 74 74 46 15
GREENVILLE 72 60 79 60 / 86 99 43 10
GREENWOOD 73 62 80 61 / 77 92 58 19
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AG/BB/ALLEN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
310 PM CDT SUN MAR 11 2012
.DISCUSSION...
THE UPPER LEVEL LOW ACROSS ERN COLO/WRN KS WILL LIFT SLOWLY NORTHEAST
THRU ERN NEB OVERNIGHT. CURRENT RADAR TRENDS AND THE RUC SUGGEST
ISOLATED SHOWERS THIS EVENING AS FAR WEST AS SWRN NEB WHICH THEN
SPREAD NORTHEAST OVERNIGHT AND EXIT THE FCST AREA BY ROUGHLY 12Z
MONDAY.
ANOTHER BIG FIRE DAY IS POSSIBLE MONDAY. BLENDED BIAS CORRECTED
MET MAV DEW PT DATA POINTS TOWARD DEW POINTS IN THE UPPER TEENS.
MEANWHILE THE STRONGER MAV WINDS AND ASSOCIATED DEEPER MIXING
PRODUCES STRONGER WINDS. SO RED FLAG CONDITIONS ARE POSSIBLE
ACROSS A LARGE PART OF THE FCST AREA. GREATER FIRE DANGER COULD
DEVELOP TUESDAY AS LOW PRESSURE ACROSS ALBERTA AND SASKATCHEWAN
DEEPENS TO AROUND 985 MB. A DRY LINE IS FCST TO DEVELOP AND PUSH
EAST TO AROUND HIGHWAY 183 WITH WINDS GUSTING TO 25 TO 30KTS. ON
WEDNESDAY CANADIAN LOW PRESSURE WILL FORCE THE DRY LINE FARTHER
EAST TO NEAR OMAHA WHICH COULD ALSO PRODUCE CRITICAL FIRE DANGER.
TEMPERATURES CONTINUE TO SOAR IN ALL MODEL SOLNS THROUGH WEDNESDAY.
THE CANADIAN LOW PRESSURE SYSTEMS WILL TRACK FAR ENOUGH NORTH TO
PREVENT ANY KIND OF STRONG COLD FRONTS AND COOLER TEMPS FROM
MOVING THROUGH THE FCST AREA BUT IT APPEARS THE SYSTEMS WILL BE
STRONG ENOUGH TO PREVENT THE DRY LINE FROM BACKING UP VERY FAR
WEST. THIS IS VERY UNCERTAIN AT THIS POINT AS WE HAVE YET TO SEE
THIS TYPE OF PATTERN AND IN WET YEARS THE DRY LINE TENDS TO HANG
OUT AROUND HIGHWAY 61.
THE GFS CONTINUES TO INDICATE SOME CIRRUS TUESDAY AND WEDNESDAY
BUT THIS SHOULD BE A FAIRLY THIN VEIL AND HAVE ONLY MINOR IMPACT ON
MAX TEMPS.
THURSDAY THROUGH SUNDAY...THE ECM CONTINUES TO KEEP A DEVELOPING
LONG WAVE TROF WEST OF THE FCST AREA. WITH NO SIGNIFICANT NRN
STREAM LEAD SHORT WAVE...THE FCST AREA SHOULD REMAIN IN THE WARM
SECTOR. A SERIES OF LOW PRESSURE SYSTEMS LIFT OUT OF THE TROF AND
THROUGH THE ROCKIES AND HIGH PLAINS. EACH WILL SUBSEQUENTLY DRAW
HIGH PRESSURE AND COOLER TEMPS CLOSER TO THE FCST AREA. THE
EARLIEST WE MIGHT SEE COOLING IS NEXT SUNDAY WHEN WINDS MAY BACK
AROUND TO THE EAST IN RESPONSE TO DEEP LOW PRESSURE ACROSS ERN WY.
THE GFS IS FASTER BRINGING THE LONG WAVE TROF EAST QUICKER. THE
FCST LEANS TOWARD THE SLOWER ECM AND WARMER TEMPS.
THERE IS SOME SPREAD IN THE POSITION OF A VERY STRONG DRY LINE FCST
TO DEVELOP ACROSS CNTL NEB IN THE EXTENDED FCST. ALL SOLNS INDICATE
DEW POINTS IN THE 50S ACROSS ERN NEB WITH 20S OVER WRN NEB. THESE
DIFFERENCES APPEAR TO BE RELATED TO THE TIMING...LOCATION AND
INTENSITY OF THE DISTURBANCES LIFTING OUT OF THE LONG WAVE TROF.
THE MODELS APPEAR TO BE DEVELOPING A BROAD AREA OF NOCTURNAL
STRATUS IN THE DEEPER MOISTURE EAST OF THE DRY LINE SO THE POSITION OF THE
DRY LINE WILL BE CLOSELY WATCHED. LATER MODEL SOLNS MAY SHOW THE
DRY LINE BACKING UP WESTWARD TOWARD A MORE CLIMATOLOGICAL
LOCATION.
&&
.AVIATION...
MVFR CEILINGS TO CONTINUE ACROSS MUCH OF WESTERN SOUTHWEST NEBRASKA
THROUGH LATE AFTERNOON TODAY...THEN EXPECTING GRADUAL CLEARING AS AN
UPPER LEVEL SYSTEM BEGINS TO PUSH EAST OF THE REGION. EXPECT
CEILINGS TO LIFT ABOVE THE MVFR FLIGHT CATEGORY SOMETIME AROUND 00Z
FOR THE KLBF FLIGHT TERMINAL. FURTHER NORTH AT KONL AND KVTN SKIES
HAVE REMAINED MOSTLY CLEAR THROUGH MUCH OF THE DAY...WITH THE CLOUD
BANK STILL SOUTH AND EAST OF THE RESPECTIVE TERMINALS. HOWEVER
STILL POSSIBLE THAT STRAY CLOUDINESS MAY INVADE THESE NORTHERN
TERMINALS...BUT UNLIKELY AT THIS POINT IN TIME. OTHERWISE GUSTY
WINDS /19020G27KT/ TO CONTINUE ACROSS NORTHERN NEBRASKA LATE THIS
AFTERNOON AS INDICATED BY MODEL GUIDANCE...BUT THEN WEAKEN OVERNIGHT
AND VEER TO THE NORTHWEST BY EARLY MORNING TOMORROW. FOR
KLBF...SOUTHERLY WIND GUSTS TO 20KTS ARE A POSSIBILITY LATE
TODAY...BUT AS WITH THE CASE OF KVTN...EXPECT THE WINDS TO REMAIN
AOB 10KTS OVERNIGHT AND VEER TO THE WEST NORTHWEST.
&&
.FIRE WEATHER...
A FIRE WEATHER WATCH HAS BEEN ISSUED FOR FIRE ZONES
204...206...209...210 AND 219 MONDAY AFTERNOON. THE COMBINATION OF
CURED FUELS...WEST NORTHWESTERLY DOWNSLOPING WIND...AND ABNORMALLY
WARM TEMPERATURES WILL CREATE CONDITIONS FAVORABLE FOR EXTREME FIRE
GROWTH. ONE CAVEAT HOWEVER...WIND SPEEDS MAY BE MARGINAL /BELOW RFW
CRITERIA/ AS HIGH PRESSURE BUILDS OVER THE REGION. BUT EMPLOYING
THE USE MAV GUIDANCE WOULD INDICATE THE POTENTIAL FOR GUSTS OF 25
MPH FOR A THREE TO FOUR HOUR PERIOD EARLY MONDAY AFTERNOON. BUFR
SOUNDINGS AND OTHER GUIDANCE INDICATE A WEAKER WIND PROFILE...WITH
THE NAM GOING AS FAR AS TO SUGGEST WIND SPEEDS OF LESS THAN 20 KTS
AT 700MB OVER MUCH OF THE CWA BY 21Z CONSIDERING THAT THE MODELS
INDICATE A RELAXING PRESSURE GRADIENT...PEAK WIND SPEEDS MAY NOT
CORRESPOND WITH PEAK HEATING/MINIMUM RH. HOWEVER...THE MODELS
GENERALLY HAVE STRUGGLED RECENTLY AND UNDERESTIMATED NOT ONLY WIND
SPEEDS BUT ALSO TEMPERATURES/RH VALUES DURING PEAK HEATING...FELT
THAT CONFIDENCE WAS HIGH ENOUGH FOR AT LEAST A FIRE WEATHER WATCH AT
THIS TIME. WILL INCLUDE MOST OF WESTERN AND NORTH CENTRAL NEBRASKA
IN THIS WATCH THAT WILL BE IN EFFECT FROM 17Z MONDAY UNTIL 01Z
TUESDAY.
FIRE HEADLINES MAY BE NEEDED FOR THE REMAINDER OF NEXT WEEK AS
RIDGING BUILDS OVER THE CENTRAL AND NORTHERN PLAINS. TEMPERATURES
BEYOND MONDAY SHOULD REMAIN IN THE 70S FOR HIGHS THROUGH THE END OF
THE WORK WEEK. IN FACT...TEMPERATURES TUESDAY THROUGH THURSDAY MAY
APPROACH 80 DEGREES ALONG AND SOUTH OF THE INTERSTATE 80
CORRIDOR...AND ACROSS MUCH OF THE CENTRAL/NORTHERN SAND HILLS. WITH
CURED FUELS IN PLACE...THESE ABOVE NORMAL TEMPERATURES WILL COMBINE
WITH MEAGER ATMOSPHERIC MOISTURE AND AT TIMES GUSTY WIND SPEEDS TO
CREATE CONDITIONS FAVORABLE FOR EXTREME FIRE BEHAVIOR. ALL FIRE
INTERESTS SHOULD MONITOR THIS SITUATION CLOSELY UNTIL APPRECIABLE
MOISTURE FALLS OR GREEN UP OCCURS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...FIRE WEATHER WATCH FROM MONDAY
AFTERNOON THROUGH MONDAY EVENING FOR NEZ204-206-209-210-219.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
918 PM EDT MON MAR 12 2012
.SYNOPSIS...
A WARM FRONT WILL BRING SHOWERS TO THE REGION AS IT MOVES THROUGH
THIS EVENING. UNSETTLED WEATHER WILL CONTINUE THROUGH TOMORROW AS
A COLD FRONT SLIDES THROUGH THE AREA. THERE WILL BE ADDITIONAL
SHOWERS...AND POSSIBLY A RUMBLE OF THUNDER...TOMORROW WITH THE
COLD FRONT PASSAGE. DRY CONDITIONS WILL ARRIVE TUESDAY NIGHT AS
HIGH PRESSURE BUILDS OVER THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
9PM UPDATE...THE MAIN WAVE OF PRECIPITATION IS NEARLY THROUGH THE
CWA, AS PREVIOUSLY THOUGHT, IF NOT EVEN A TAD QUICKER THAN THAT.
THE THIRD LINE OF PRECIPITATION HAS BARELY HELD ITS OWN. IT LOOKS
TO MAINLY AFFECT NEPA AND THE SOUTHERN EDGE OF THE SOUTHERN TIER.
IT IS A SMALL, QUICK MOVING LINE THAT WILL ONLY TAKE ABOUT 20 TO
30 MINUTES TO TRAVERSE A LOCATION. GIVEN THIS, DID NOT
SIGNIFICANTLY RAISE POPS FOR THIS, BUT DID KEEP A MENTION OF RAIN
IN THE FORECAST FOR MOST OF THE NIGHT. A COLD FRONT IS STILL
EXPECTED TO MOVE THROUGH TOMORROW, BRINGING ANOTHER ROUND OF RAIN
SHOWERS ACROSS THE CWA, AND MAYBE SOME THUNDER TO NEPA, SOUTHERN
TIER OF NY, AND WESTERN CATSKILLS.
7PM UPDATE...FORECASTED PRECIP IS COMING IN, BUT AHEAD OF
SCHEDULE. THE SECOND LINE OF SHOWERS IS ALREADY ENTERING THE
WESTERN ZONES. THE HRRR HAS HAD A PRETTY GOOD HANDLE ON, SO HAVE
FOLLOWED ITS LEAD WITH TIMING. HOWEVER, THERE IS A THIRD, WEAKER
LINE OF SHOWERS THAT THE HRRR MAY BE HAVING A LITTLE TROUBLE WITH.
WITH HAVE TO WATCH THIS LINE TO SEE IF IT HOLDS TOGETHER AS IT
APPROACHES THE CWA. HAVE MADE ADJUSTMENTS TO THE FORECAST IN
REGARDS TO TIMING.
FOR TOMORROW, HAVE ALSO TWEAKED TIMING AND ANY CONVECTION WITH NEW
MODEL UPDATES. NOT MANY CHANGES TO TOMORROWS FORECAST, OTHER THEN
TIMING AND CONVECTION COVERAGE.
PREVIOUS DISCUSSION...MAIN STORY DURING THE NEAR TERM WILL BE
UNSETTLED WEATHER CONDITIONS BOTH TONIGHT AND ON TUESDAY AS AN
OCCLUDED WEATHER SYSTEM PASSES TO OUR NORTH. LATEST SURFACE
ANALYSIS PLACES THE MAIN WARM FRONT OF INTEREST FROM WEST-CENTRAL
MI...SOUTHEAST THROUGH WESTERN OH AND SOUTHERN WV. REGIONAL RADARS
SHOWING A WELL DEVELOPED RAIN SHIELD HEADING OUR WAY WITH LATEST
RADAR SHOTS FROM KBUF SHOWING PRECIP NOW AS FAR EAST AS THE
WESTERN SOUTHERN TIER. AS THE LATE AFTERNOON/EARLY EVENING HOURS
PROGRESS...EXPECT RAIN TO GRADUALLY OVERSPREAD THE REGION AND HAVE
PRETTY MUCH GONE WITH CATEGORICAL POPS EVERYWHERE THROUGH 09Z.
PRECIP WILL QUICKLY EXIT OFF TO OUR EAST ON BY 10Z AS A MID-LEVEL
DRY PUNCH ENTERS OUR REGION AHEAD THE NEXT COLD FRONT PROGGED TO
ENTER AROUND 12Z TUE.
COLD FRONT WILL QUICKLY APPROACH THE AREA FROM THE NORTHWEST AFTER
12Z TUE. MAIN CONCERN WITH ITS PASSAGE WILL BE POSSIBLE THUNDER
ACTIVITY AS ATMOSPHERE AHEAD OF THE BOUNDARY BECOMES WEAKLY
UNSTABLE WITH BUFKIT DEFINED MLCAPE VALUES APPROACHING 700 J/KG
ACROSS NORTHEAST PA. LATEST SPC DAY 2 OUTLOOK PLACES SOUTHERN
TWO-THIRDS OF THE CWA IN GENERAL THUNDER WITH A "SEE TEXT" FOR LOW
END SEVERE POTENTIAL. BEST INSTABILITY WILL BE LOCATED SOUTH OF
THE STATE LINE...WHERE UPPER-LEVEL WIND FIELDS WILL BE SLIGHTLY
WEAKER DUE TO FURTHER DISPLACEMENT FROM MAIN POLAR VORTEX SPINNING
ACROSS SOUTHERN ONTARIO. THAT SAID...0-6KM BULK SHEAR VECTORS
APPROACH 40 KTS PRIOR TO FRONTAL PASSAGE WHICH MAY SUPPORT
ISOLATED STRONG STORMS ALONG AND HEAD OF THE BOUNDARY AS IT PASSES
SOUTHEAST ACROSS THE CWA. MODEL RH FIELDS AND ACCOMPANYING
THERMODYNAMIC PROFILES SHOW A FAIR AMOUNT OF DRY AIR ALOFT WHICH
COULD SUPPORT ISOLATED STRONG WIND POTENTIAL WITH ANY DEVELOPING
DOWNDRAFTS. WITH PROSPECTS FOR ORGANIZED CONVECTION AND THE EARLY
SEASON NATURE OF THE EVENT...WILL HIGHLIGHT CONCERNS IN THE HWO
PRODUCT.
COLD FRONT TO QUICKLY EXIT OFF TO OUR SOUTH AND EAST TUE NIGHT
WHICH WILL BE FOLLOWED BY ARRIVING HIGH PRESSURE AND DRY
CONDITIONS FOR THE OVERNIGHT PERIOD.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
UPR LOW OVER SRN QUEBEC MVS SLOWLY EAST ON WED. ENUF INFLUENCE
FROM THE COLD POOL ALOFT TO BRING A CHANCE OF SHWRS TO THE XTRM
NORTH ON WED...WHILE DRIER AIR ROTATES ARND THE LOW INTO THE CNTRL
AND SRN ZONES. RDGG CONTS TO BLD LTR WED INTO THU AS THE UPR LOW
DRIFTS EAST. A WEAK SFC HIPRES BLDS IN FOR THU AS MOISTURE SLAMS
INTO THE RDG OVER THE LAKES. RDG HOLDS FAST SO PCPN NOT
XPCTD...BUT SOME PTCHY CLDS SEEM LIKELY ON THU AS THE UPR MOISTURE
SLOWLY RETURNS.
TEMPS SHD REBOUND QUICKLY AS H8 TEMPS RISE FROM NEAR 0C WED TO 8C
BY THU.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS ARE IN PRETTY GOOD AGREEMENT FOR THURSDAY NIGHT. THEY
INDICATE A LARGE AREA OF UNSETTLED WEATHER OVER THE MISSISSIPPI
VALLEY AND THE MIDWEST, THROUGH THE GREAT LAKES. THERE WILL
SOUTHERLY FLOW FROM THE GULF OF MEXICO, WHICH WILL BRING UP SOME
MOISTURE. THERE ARE ALSO SEVERAL EMBEDDED SHORT WAVES IN A WEAK
500MB RIDGE. THERE ALSO LOOKS TO BE SEVERAL WEAK TROUGHS AT THE
SFC. GIVEN ALL THESE INGREDIENTS, THERE WILL BE A LOT OF
INSTABILITY AROUND, WITH PLENTY OF AVAILABLE MOISTURE TO ALLOW
CONVECTION TO FIRE. THE AREA OF INSTABILITY SHOULD PUSH OFF TO THE
EAST ON FRIDAY AND BEGIN TO AFFECT THE CWA. BOTH THE GFS AND THE
ECMWF ARE KEEPING A MORE STABLE AIR MASS OVER THE AREA. SO,
THINKING IS THAT WHILE STORMS MAY APPROACH THE AREA, THEY WILL
WEAKEN AND BEGIN TO FALL APART AS THEY ARRIVE, LEAVING SCATTERED
RAIN SHOWERS TO MOVE ACROSS. SATURDAY WILL BE A LITTLE MORE OF THE
SAME, BUT CAPE AND NEGATIVE LIS MAY TRY TO INTRUDE ON THE AREA,
SO, WOULD NOT BE SURPRISED IF THERE ARE FEW RUMBLES OF THUNDER
FRIDAY OR SATURDAY. BOTH MODELS ARE IN GOOD AGREEMENT WITH A
STRONG RIDGE BUILDING FOR THE BEGINNING OF THE WEEK. THEY SHOW THE
RIDGE AXIS NEARLY OVER THE CWA, WITH 500MB HEIGHTS AT 580DM+. WILL
BE INTERESTING TO SEE HOW THIS EVOLVES. IF THEY ARE CORRECT, THE
AREA COULD HAVE A STRONG CAP FOR THE BEGINNING OF NEXT WEEK, AS
WELL AS TEMPERATURES THAT ARE WELL ABOVE NORMAL, EVEN POSSIBLE
RECORD SETTING. HOWEVER, IT IS STILL WELL INTO THE FUTURE AND
STILL A GREAT DEAL OF UNCERTAINTY EXISTS.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
LOW MVG THRU THE WESTERN LAKES WILL PUSH AN UPR LVL WRM FNT AND
MOISTURE INTO THE AREA TNGT PERSISTING INTO TUE MRNG...WITH CDFNT
FOLLOWING CLOSE BEHIND. BAND OF --SHRA CRNTLY MOVG THRU THE RGN WITH
VFR...BUT CIGS WILL LOWER LATER THIS EVNG AND OVRNGT TO MVFR/IFR
AND PERSIST INTO TUE MRNG. AS THE CDFNT MOVS THRU ON TUE...POTNL FOR
ADDNL -SHRA AND PSBLY -TSRA. BEST CHC SEEMS TO BE AT AVP IN THE
AFTN SO INDICATED A PROB30 THERE. XPCT CONDITIONS TO IMPRV ON TUE
AFTN AS DRIER AIR WORKS IN BEHIND THE FNT. ONE OTHER CNCRN FOR
TNGT IS STRONG LL WINDS JUST ABV THE DECK AS THE BNDRY LYR
STABILIZES. THIS COULD ALLOW FOR LLWS OVER THE NY COUNTIES WITH
SWLY FLOW NEAR 40KTS AT 2K FT.
.OUTLOOK...
TUE NGT THRU THU...MAINLY VFR.
FRI/SAT...POSSIBLE MVFR/IFR IN -SHRA. CLRG LATE SAT.
&&
.FIRE WEATHER...
FOR TODAY...MINIMUM RH VALUES WILL BE A LITTLE HIGHER RUNNING IN THE
LOW TO MID 30S IN NORTHEAST PENNSYLVANIA AND INTO THE MID 30S TO
LOWER 40S IN CENTRAL NY. IN ADDITION...WINDS GUSTS WILL BE LESS
THAN 15-20 MPH. FINE FUELS THOUGH WILL REMAIN DRY THRU THIS AFTERNOON
UNTIL SHOWERS ARRIVE LATE IN THE DAY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/SLI
NEAR TERM...CMG/SLI
SHORT TERM...DGM
LONG TERM...SLI
AVIATION...
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
741 PM EDT MON MAR 12 2012
.SYNOPSIS...
A WARM FRONT WILL BRING SHOWERS TO THE REGION AS IT MOVES THROUGH.
UNSETTLED WEATHER WILL CONTINUE THROUGH TOMORROW AS A COLD FRONT SLIDES
THROUGH THE AREA. THERE WILL BE ADDITIONAL SHOWERS...AND POSSIBLY A
RUMBLE OF THUNDER...TOMORROW WITH THE COLD FRONT PASSAGE. DRY CONDITIONS
WILL ARRIVE TUESDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
7PM UPDATE...FORECASTED PRECIP IS COMING IN, BUT AHEAD OF
SCHEDULE. THE SECOND LINE OF SHOWERS IS ALREADY ENTERING THE
WESTERN ZONES. THE HRRR HAS HAD A PRETTY GOOD HANDLE ON, SO HAVE
FOLLOWED ITS LEAD WITH TIMING. HOWEVER, THERE IS A THIRD, WEAKER
LINE OF SHOWERS THAT THE HRRR MAY BE HAVING A LITTLE TROUBLE WITH.
WITH HAVE TO WATCH THIS LINE TO SEE IF IT HOLDS TOGETHER AS IT
APPROACHES THE CWA. HAVE MADE ADJUSTMENTS TO THE FORECAST IN
REGARDS TO TIMING.
FOR TOMORROW, HAVE ALSO TWEAKED TIMING AND ANY CONVECTION WITH NEW
MODEL UPDATES. NOT MANY CHANGES TO TOMORROWS FORECAST, OTHER THEN
TIMING AND CONVECTION COVERAGE.
PREVIOUS DISCUSSION...MAIN STORY DURING THE NEAR TERM WILL BE
UNSETTLED WEATHER CONDITIONS BOTH TONIGHT AND ON TUESDAY AS AN
OCCLUDED WEATHER SYSTEM PASSES TO OUR NORTH. LATEST SURFACE
ANALYSIS PLACES THE MAIN WARM FRONT OF INTEREST FROM WEST-CENTRAL
MI...SOUTHEAST THROUGH WESTERN OH AND SOUTHERN WV. REGIONAL RADARS
SHOWING A WELL DEVELOPED RAIN SHIELD HEADING OUR WAY WITH LATEST
RADAR SHOTS FROM KBUF SHOWING PRECIP NOW AS FAR EAST AS THE
WESTERN SOUTHERN TIER. AS THE LATE AFTERNOON/EARLY EVENING HOURS
PROGRESS...EXPECT RAIN TO GRADUALLY OVERSPREAD THE REGION AND HAVE
PRETTY MUCH GONE WITH CATEGORICAL POPS EVERYWHERE THROUGH 09Z.
PRECIP WILL QUICKLY EXIT OFF TO OUR EAST ON BY 10Z AS A MID-LEVEL
DRY PUNCH ENTERS OUR REGION AHEAD THE NEXT COLD FRONT PROGGED TO
ENTER AROUND 12Z TUE.
COLD FRONT WILL QUICKLY APPROACH THE AREA FROM THE NORTHWEST AFTER
12Z TUE. MAIN CONCERN WITH ITS PASSAGE WILL BE POSSIBLE THUNDER
ACTIVITY AS ATMOSPHERE AHEAD OF THE BOUNDARY BECOMES WEAKLY
UNSTABLE WITH BUFKIT DEFINED MLCAPE VALUES APPROACHING 700 J/KG
ACROSS NORTHEAST PA. LATEST SPC DAY 2 OUTLOOK PLACES SOUTHERN
TWO-THIRDS OF THE CWA IN GENERAL THUNDER WITH A "SEE TEXT" FOR LOW
END SEVERE POTENTIAL. BEST INSTABILITY WILL BE LOCATED SOUTH OF
THE STATE LINE...WHERE UPPER-LEVEL WIND FIELDS WILL BE SLIGHTLY
WEAKER DUE TO FURTHER DISPLACEMENT FROM MAIN POLAR VORTEX SPINNING
ACROSS SOUTHERN ONTARIO. THAT SAID...0-6KM BULK SHEAR VECTORS
APPROACH 40 KTS PRIOR TO FRONTAL PASSAGE WHICH MAY SUPPORT
ISOLATED STRONG STORMS ALONG AND HEAD OF THE BOUNDARY AS IT PASSES
SOUTHEAST ACROSS THE CWA. MODEL RH FIELDS AND ACCOMPANYING
THERMODYNAMIC PROFILES SHOW A FAIR AMOUNT OF DRY AIR ALOFT WHICH
COULD SUPPORT ISOLATED STRONG WIND POTENTIAL WITH ANY DEVELOPING
DOWNDRAFTS. WITH PROSPECTS FOR ORGANIZED CONVECTION AND THE EARLY
SEASON NATURE OF THE EVENT...WILL HIGHLIGHT CONCERNS IN THE HWO
PRODUCT.
COLD FRONT TO QUICKLY EXIT OFF TO OUR SOUTH AND EAST TUE NIGHT
WHICH WILL BE FOLLOWED BY ARRIVING HIGH PRESSURE AND DRY
CONDITIONS FOR THE OVERNIGHT PERIOD.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
UPR LOW OVER SRN QUEBEC MVS SLOWLY EAST ON WED. ENUF INFLUENCE
FROM THE COLD POOL ALOFT TO BRING A CHANCE OF SHWRS TO THE XTRM
NORTH ON WED...WHILE DRIER AIR ROTATES ARND THE LOW INTO THE CNTRL
AND SRN ZONES. RDGG CONTS TO BLD LTR WED INTO THU AS THE UPR LOW
DRIFTS EAST. A WEAK SFC HIPRES BLDS IN FOR THU AS MOISTURE SLAMS
INTO THE RDG OVER THE LAKES. RDG HOLDS FAST SO PCPN NOT
XPCTD...BUT SOME PTCHY CLDS SEEM LIKELY ON THU AS THE UPR MOISTURE
SLOWLY RETURNS.
TEMPS SHD REBOUND QUICKLY AS H8 TEMPS RISE FROM NEAR 0C WED TO 8C
BY THU.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS ARE IN PRETTY GOOD AGREEMENT FOR THURSDAY NIGHT. THEY
INDICATE A LARGE AREA OF UNSETTLED WEATHER OVER THE MISSISSIPPI
VALLEY AND THE MIDWEST, THROUGH THE GREAT LAKES. THERE WILL
SOUTHERLY FLOW FROM THE GULF OF MEXICO, WHICH WILL BRING UP SOME
MOISTURE. THERE ARE ALSO SEVERAL EMBEDDED SHORT WAVES IN A WEAK
500MB RIDGE. THERE ALSO LOOKS TO BE SEVERAL WEAK TROUGHS AT THE
SFC. GIVEN ALL THESE INGREDIENTS, THERE WILL BE A LOT OF
INSTABILITY AROUND, WITH PLENTY OF AVAILABLE MOISTURE TO ALLOW
CONVECTION TO FIRE. THE AREA OF INSTABILITY SHOULD PUSH OFF TO THE
EAST ON FRIDAY AND BEGIN TO AFFECT THE CWA. BOTH THE GFS AND THE
ECMWF ARE KEEPING A MORE STABLE AIR MASS OVER THE AREA. SO,
THINKING IS THAT WHILE STORMS MAY APPROACH THE AREA, THEY WILL
WEAKEN AND BEGIN TO FALL APART AS THEY ARRIVE, LEAVING SCATTERED
RAIN SHOWERS TO MOVE ACROSS. SATURDAY WILL BE A LITTLE MORE OF THE
SAME, BUT CAPE AND NEGATIVE LIS MAY TRY TO INTRUDE ON THE AREA,
SO, WOULD NOT BE SURPRISED IF THERE ARE FEW RUMBLES OF THUNDER
FRIDAY OR SATURDAY. BOTH MODELS ARE IN GOOD AGREEMENT WITH A
STRONG RIDGE BUILDING FOR THE BEGINNING OF THE WEEK. THEY SHOW THE
RIDGE AXIS NEARLY OVER THE CWA, WITH 500MB HEIGHTS AT 580DM+. WILL
BE INTERESTING TO SEE HOW THIS EVOLVES. IF THEY ARE CORRECT, THE
AREA COULD HAVE A STRONG CAP FOR THE BEGINNING OF NEXT WEEK, AS
WELL AS TEMPERATURES THAT ARE WELL ABOVE NORMAL, EVEN POSSIBLE
RECORD SETTING. HOWEVER, IT IS STILL WELL INTO THE FUTURE AND
STILL A GREAT DEAL OF UNCERTAINTY EXISTS.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
LOW MVG THRU THE WESTERN LAKES WILL PUSH AN UPR LVL WRM FNT AND
MOISTURE INTO THE AREA TNGT PERSISTING INTO TUE MRNG...WITH CDFNT
FOLLOWING CLOSE BEHIND. BAND OF --SHRA CRNTLY MOVG THRU THE RGN WITH
VFR...BUT CIGS WILL LOWER LATER THIS EVNG AND OVRNGT TO MVFR/IFR
AND PERSIST INTO TUE MRNG. AS THE CDFNT MOVS THRU ON TUE...POTNL FOR
ADDNL -SHRA AND PSBLY -TSRA. BEST CHC SEEMS TO BE AT AVP IN THE
AFTN SO INDICATED A PROB30 THERE. XPCT CONDITIONS TO IMPRV ON TUE
AFTN AS DRIER AIR WORKS IN BEHIND THE FNT. ONE OTHER CNCRN FOR
TNGT IS STRONG LL WINDS JUST ABV THE DECK AS THE BNDRY LYR
STABILIZES. THIS COULD ALLOW FOR LLWS OVER THE NY COUNTIES WITH
SWLY FLOW NEAR 40KTS AT 2K FT.
.OUTLOOK...
TUE NGT THRU THU...MAINLY VFR.
FRI/SAT...POSSIBLE MVFR/IFR IN -SHRA. CLRG LATE SAT.
&&
.FIRE WEATHER...
FOR TODAY...MINIMUM RH VALUES WILL BE A LITTLE HIGHER RUNNING IN THE
LOW TO MID 30S IN NORTHEAST PENNSYLVANIA AND INTO THE MID 30S TO
LOWER 40S IN CENTRAL NY. IN ADDITION...WINDS GUSTS WILL BE LESS
THAN 15-20 MPH. FINE FUELS THOUGH WILL REMAIN DRY THRU THIS AFTERNOON
UNTIL SHOWERS ARRIVE LATE IN THE DAY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/SLI
SHORT TERM...DGM
LONG TERM...SLI
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
709 PM EDT MON MAR 12 2012
.SYNOPSIS...
A WARM FRONT WILL BRING SHOWERS TO THE REGION AS IT MOVES THROUGH.
UNSETTLED WEATHER WILL CONTINUE THROUGH TOMORROW AS A COLD FRONT SLIDES
THROUGH THE AREA. THERE WILL BE ADDITIONAL SHOWERS...AND POSSIBLY A
RUMBLE OF THUNDER...TOMORROW WITH THE COLD FRONT PASSAGE. DRY CONDITIONS
WILL ARRIVE TUESDAY NIGHT AS HIGH PRESSURE BUILDS OVER THE AREA.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
7PM UPDATE...FORECASTED PRECIP IS COMING IN, BUT AHEAD OF
SCHEDULE. THE SECOND LINE OF SHOWERS IS ALREADY ENTERING THE
WESTERN ZONES. THE HRRR HAS HAD A PRETTY GOOD HANDLE ON, SO HAVE
FOLLOWED ITS LEAD WITH TIMING. HOWEVER, THERE IS A THIRD, WEAKER
LINE OF SHOWERS THAT THE HRRR MAY BE HAVING A LITTLE TROUBLE WITH.
WITH HAVE TO WATCH THIS LINE TO SEE IF IT HOLDS TOGETHER AS IT
APPROACHES THE CWA. HAVE MADE ADJUSTMENTS TO THE FORECAST IN
REGARDS TO TIMING.
FOR TOMORROW, HAVE ALSO TWEAKED TIMING AND ANY CONVECTION WITH NEW
MODEL UPDATES. NOT MANY CHANGES TO TOMORROWS FORECAST, OTHER THEN
TIMING AND CONVECTION COVERAGE.
PREVIOUS DISCUSSION...MAIN STORY DURING THE NEAR TERM WILL BE
UNSETTLED WEATHER CONDITIONS BOTH TONIGHT AND ON TUESDAY AS AN
OCCLUDED WEATHER SYSTEM PASSES TO OUR NORTH. LATEST SURFACE
ANALYSIS PLACES THE MAIN WARM FRONT OF INTEREST FROM WEST-CENTRAL
MI...SOUTHEAST THROUGH WESTERN OH AND SOUTHERN WV. REGIONAL RADARS
SHOWING A WELL DEVELOPED RAIN SHIELD HEADING OUR WAY WITH LATEST
RADAR SHOTS FROM KBUF SHOWING PRECIP NOW AS FAR EAST AS THE
WESTERN SOUTHERN TIER. AS THE LATE AFTERNOON/EARLY EVENING HOURS
PROGRESS...EXPECT RAIN TO GRADUALLY OVERSPREAD THE REGION AND HAVE
PRETTY MUCH GONE WITH CATEGORICAL POPS EVERYWHERE THROUGH 09Z.
PRECIP WILL QUICKLY EXIT OFF TO OUR EAST ON BY 10Z AS A MID-LEVEL
DRY PUNCH ENTERS OUR REGION AHEAD THE NEXT COLD FRONT PROGGED TO
ENTER AROUND 12Z TUE.
COLD FRONT WILL QUICKLY APPROACH THE AREA FROM THE NORTHWEST AFTER
12Z TUE. MAIN CONCERN WITH ITS PASSAGE WILL BE POSSIBLE THUNDER
ACTIVITY AS ATMOSPHERE AHEAD OF THE BOUNDARY BECOMES WEAKLY
UNSTABLE WITH BUFKIT DEFINED MLCAPE VALUES APPROACHING 700 J/KG
ACROSS NORTHEAST PA. LATEST SPC DAY 2 OUTLOOK PLACES SOUTHERN
TWO-THIRDS OF THE CWA IN GENERAL THUNDER WITH A "SEE TEXT" FOR LOW
END SEVERE POTENTIAL. BEST INSTABILITY WILL BE LOCATED SOUTH OF
THE STATE LINE...WHERE UPPER-LEVEL WIND FIELDS WILL BE SLIGHTLY
WEAKER DUE TO FURTHER DISPLACEMENT FROM MAIN POLAR VORTEX SPINNING
ACROSS SOUTHERN ONTARIO. THAT SAID...0-6KM BULK SHEAR VECTORS
APPROACH 40 KTS PRIOR TO FRONTAL PASSAGE WHICH MAY SUPPORT
ISOLATED STRONG STORMS ALONG AND HEAD OF THE BOUNDARY AS IT PASSES
SOUTHEAST ACROSS THE CWA. MODEL RH FIELDS AND ACCOMPANYING
THERMODYNAMIC PROFILES SHOW A FAIR AMOUNT OF DRY AIR ALOFT WHICH
COULD SUPPORT ISOLATED STRONG WIND POTENTIAL WITH ANY DEVELOPING
DOWNDRAFTS. WITH PROSPECTS FOR ORGANIZED CONVECTION AND THE EARLY
SEASON NATURE OF THE EVENT...WILL HIGHLIGHT CONCERNS IN THE HWO
PRODUCT.
COLD FRONT TO QUICKLY EXIT OFF TO OUR SOUTH AND EAST TUE NIGHT
WHICH WILL BE FOLLOWED BY ARRIVING HIGH PRESSURE AND DRY
CONDITIONS FOR THE OVERNIGHT PERIOD.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
UPR LOW OVER SRN QUEBEC MVS SLOWLY EAST ON WED. ENUF INFLUENCE
FROM THE COLD POOL ALOFT TO BRING A CHANCE OF SHWRS TO THE XTRM
NORTH ON WED...WHILE DRIER AIR ROTATES ARND THE LOW INTO THE CNTRL
AND SRN ZONES. RDGG CONTS TO BLD LTR WED INTO THU AS THE UPR LOW
DRIFTS EAST. A WEAK SFC HIPRES BLDS IN FOR THU AS MOISTURE SLAMS
INTO THE RDG OVER THE LAKES. RDG HOLDS FAST SO PCPN NOT
XPCTD...BUT SOME PTCHY CLDS SEEM LIKELY ON THU AS THE UPR MOISTURE
SLOWLY RETURNS.
TEMPS SHD REBOUND QUICKLY AS H8 TEMPS RISE FROM NEAR 0C WED TO 8C
BY THU.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS ARE IN PRETTY GOOD AGREEMENT FOR THURSDAY NIGHT. THEY
INDICATE A LARGE AREA OF UNSETTLED WEATHER OVER THE MISSISSIPPI
VALLEY AND THE MIDWEST, THROUGH THE GREAT LAKES. THERE WILL
SOUTHERLY FLOW FROM THE GULF OF MEXICO, WHICH WILL BRING UP SOME
MOISTURE. THERE ARE ALSO SEVERAL EMBEDDED SHORT WAVES IN A WEAK
500MB RIDGE. THERE ALSO LOOKS TO BE SEVERAL WEAK TROUGHS AT THE
SFC. GIVEN ALL THESE INGREDIENTS, THERE WILL BE A LOT OF
INSTABILITY AROUND, WITH PLENTY OF AVAILABLE MOISTURE TO ALLOW
CONVECTION TO FIRE. THE AREA OF INSTABILITY SHOULD PUSH OFF TO THE
EAST ON FRIDAY AND BEGIN TO AFFECT THE CWA. BOTH THE GFS AND THE
ECMWF ARE KEEPING A MORE STABLE AIR MASS OVER THE AREA. SO,
THINKING IS THAT WHILE STORMS MAY APPROACH THE AREA, THEY WILL
WEAKEN AND BEGIN TO FALL APART AS THEY ARRIVE, LEAVING SCATTERED
RAIN SHOWERS TO MOVE ACROSS. SATURDAY WILL BE A LITTLE MORE OF THE
SAME, BUT CAPE AND NEGATIVE LIS MAY TRY TO INTRUDE ON THE AREA,
SO, WOULD NOT BE SURPRISED IF THERE ARE FEW RUMBLES OF THUNDER
FRIDAY OR SATURDAY. BOTH MODELS ARE IN GOOD AGREEMENT WITH A
STRONG RIDGE BUILDING FOR THE BEGINNING OF THE WEEK. THEY SHOW THE
RIDGE AXIS NEARLY OVER THE CWA, WITH 500MB HEIGHTS AT 580DM+. WILL
BE INTERESTING TO SEE HOW THIS EVOLVES. IF THEY ARE CORRECT, THE
AREA COULD HAVE A STRONG CAP FOR THE BEGINNING OF NEXT WEEK, AS
WELL AS TEMPERATURES THAT ARE WELL ABOVE NORMAL, EVEN POSSIBLE
RECORD SETTING. HOWEVER, IT IS STILL WELL INTO THE FUTURE AND
STILL A GREAT DEAL OF UNCERTAINTY EXISTS.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
LOW MVG THRU THE WESTERN LAKES WILL PUSH AN UPR LVL WRM FNT AND
MOISTURE INTO THE AREA TNGT AND EARLY TUE. THIS WILL RESULT IN
LWRD CIGS AND VSBYS AFT 00Z WITH SCT SHWRS. OTR CNCRN IS STRONG LL
WINDS...JUST ABV THE DECK AS THE BNDRY LYR STABILIZES OVRNGT. THIS
COULD ALLOW FOR LLWS OVER THE NY COUNTIES WITH SWLY FLOW NEAR
40KTS AT 2K FT. OTRW...XPCT SLOW IMPRVMT AFT 12Z TUE AS DRIER AIR
BEGINS TO WRK IN FROM THE SW AND THE BNDRY LYR MIXES.
.OUTLOOK...
TUE AFTN...MVFR IN -SHRA...WITH SCT TSRA POSSIBLE.
TUE NGT THRU THU...MAINLY VFR.
FRI/SAT...POSSIBLE MVFR/IFR IN -SHRA. CLRG LATE SAT.
&&
.FIRE WEATHER...
FOR TODAY...MINIMUM RH VALUES WILL BE A LITTLE HIGHER RUNNING IN THE
LOW TO MID 30S IN NORTHEAST PENNSYLVANIA AND INTO THE MID 30S TO
LOWER 40S IN CENTRAL NY. IN ADDITION...WINDS GUSTS WILL BE LESS
THAN 15-20 MPH. FINE FUELS THOUGH WILL REMAIN DRY THRU THIS AFTERNOON
UNTIL SHOWERS ARRIVE LATE IN THE DAY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG
NEAR TERM...CMG/SLI
SHORT TERM...DGM
LONG TERM...SLI
AVIATION...DGM
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
940 PM EDT MON MAR 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO LINGER OFFSHORE...AND EXTEND OVER
MUCH OF THE REGION...FOR A GOOD PART OF THE WORK WEEK. AN UPPER
LEVEL DISTURBANCE APPROACHES OVERNIGHT AND TUESDAY...BRINGING A GOOD
CHANCE OF SHOWERS TO THE REGION. TEMPERATURES SHOULD BE WELL ABOVE
NORMAL AT LEAST THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM MONDAY...
PRECIP JUST TO THE WEST OF THE FORECAST AREA SEEMS TO BE DRIVEN
MOSTLY BY A MID-LEVEL VORT MAX THAT MOST LIKELY DEVELOPED FROM THE
DEEP CONVECTION THAT OCCURRED ACROSS THE LA/MS GULF COAST REGION
THIS MORNING. THE LATEST RUC DATA...AS WELL AS OTHER MODELS...HAVE
PICKED THIS FEATURE UP RATHER WELL AND SHOWS IT PROGRESSING THROUGH
CENTRAL NC OVERNIGHT. IT APPEARS THE DPVA ASSOCIATED WITH THIS
FEATURE WILL PROVIDE ENOUGH FORCING AND DESPITE THE POOR
THERMODYNAMICS...SCATTERED SHOWERS WILL BE POSSIBLE. AS SUCH...MANY
OF THE LATEST HIGH RES SIMULATED REFLECTIVITY DATA (WRF NMM, WRF
ARW, HRRR, AMONG OTHERS) SHOW AN AREA OF LIGHT TO MODERATE PRECIP
MOVING THROUGH THE FORECAST AREA FROM WEST TO EAST OVERNIGHT AND
INTO TUESDAY MORNING...BEGINNING AROUND 03-06Z ACROSS THE WEST.
THEREFORE...WENT AHEAD AND INCREASED POPS TO HIGH END CHANCE ACROSS
THE ENTIRE FORECAST AREA OVERNIGHT. AT THIS TIME...IT APPEARS LITTLE
TO NO INSTABILITY WILL BE PRESENT DURING THE OVERNIGHT HOURS AND
THEREFORE...THUNDER SHOULD NOT BE A THREAT. ANOTHER SHORTWAVE WILL
APPROACH FROM THE WEST BY EARLY TUESDAY WHICH MAY ALSO ENHANCE THE
FORCING OVER THE AREA...BUT AT THIS TIME IT APPEARS THE BEST FORCING
ASSOCIATED WITH THIS WAVE WILL OCCUR AFTER SUNRISE (SEE SHORT TERM
DISCUSSION BELOW FOR MORE DETAILS). WITH MOSTLY CLOUDY OR OVERCAST
SKIES AND THE INCREASE IN LOW LEVEL MOISTURE...AM EXPECTING WARMER
OVERNIGHT LOWS TONIGHT...GENERALLY IN THE LOW TO MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM MONDAY...
TUESDAY:
AN AMPLIFYING SHORTWAVE IS EXPECTED TO PROGRESS EASTWARD ACROSS THE
CAROLINAS DURING THE DAY TUE...THOUGH THE EXACT TIMING REMAINS
SOMEWHAT UNCERTAIN. IN THE LOWER LEVELS...A PIEDMONT TROUGH DURING
IS PROGGED TO DEVELOP DURING PEAK HEATING. OTHERWISE...LIFT WILL BE
CONFINED TO VERY WEAK/BROAD LOW-LEVEL WARM ADVECTION AND MID-LEVEL
HEIGHT FALLS. W/REGARD TO THERMODYNAMICS...DESTABILIZATION WILL
LIKELY BE HAMPERED BY PERVASIVE CLOUD COVER THROUGH MUCH OF THE
DAY...PARTICULARLY EAST OF HIGHWAY 1. SOME CLEARING IS EXPECTED IN
THE WEST/NW PIEDMONT BY ~18Z IN THE PRESENCE OF A CONTINUED MOIST
BOUNDARY LAYER...AND INSTABILITY COULD ACTUALLY BE MORE FAVORABLE
WEST OF HWY 1. HOWEVER...SIGNIFICANT DRYING ALOFT IS ALSO EXPECTED
AS A MUCH DRIER MID/UPPER LEVEL AIRMASS ADVECTS INTO WESTERN
PORTIONS OF THE STATE TUE AFTERNOON...AND DRY AIR ENTRAINMENT MAY
OFFSET OR COMPLETELY NEGATE THE BENEFIT OF BETTER INSOLATION.
REGARDLESS...WITH WEAK MID-LEVEL LAPSE RATES OVER MOST OF THE AREA
(ASIDE FROM WEST/NW PIEDMONT) DURING PEAK HEATING...MLCAPE VALUES
WILL LIKELY NOT EXCEED 250-500 J/KG. WITH THE ABOVE IN MIND...EXPECT
SUFFICIENT FORCING AND INSTABILITY TO WARRANT AT LEAST A LOW CHANCE
(20-30%) OF SHOWERS/ STORMS...WITH THE BEST CHANCE OF THUNDER EAST
OF HIGHWAY 1. HOWEVER...IF FORCING ASSOC/W THE UPPER LEVEL WAVE IS
STRONG ENOUGH TO OVERCOME THE SIGNIFICANT AMOUNT OF DRY AIR ALOFT
PROGGED IN THE WEST/NW PIEDMONT...THUNDER WILL BE POSSIBLE THERE AS
WELL. GIVEN MARGINAL INSTABILITY...0-6 KM BULK SHEAR VALUES NO
HIGHER THAN 20-25 KT (BARELY SUPPORTIVE OF MULTICELLULAR
CONVECTION)...AND A RELATIVELY SHALLOW MIXED LAYER WITH LITTLE
POTENTIAL FOR EVAPORATIVELY ENHANCED DOWNDRAFTS...DO NOT ANTICIPATE
A SEVERE THREAT WITH ANY CONVECTION. EXPECT HIGHS ON TUE TO RANGE
FROM THE UPPER 60S/LOWER 70S IN THE EAST TO THE LOWER/MID 70S IN THE
WEST.
TUESDAY NIGHT:
SUBSIDENCE AND SHORTWAVE RIDGING BUILDING INTO THE AREA IN THE WAKE
OF THE SHORTWAVE SHOULD RESULT IN MOSTLY CLEAR SKIES TUE NIGHT.
GIVEN A WEAK/BAGGY MSLP GRADIENT AND THE CONTINUED PRESENCE OF A
MOIST BOUNDARY LAYER...ANTICIPATE A POTENTIAL FOR FOG ACROSS THE
AREA 06-12Z WED MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAINFALL
DURING THE DAY TUE. EXPECT LOWS IN THE LOWER/MID 50S. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...
AS SURFACE SYSTEM MOVES OFFSHORE EARLY WEDNESDAY...WARM AIR WILL BE
SPREADING NORTH DUE TO SUBTROPICAL RIDGING INTO THE SOUTHERN PLAINS
AND WESTERN GULF STATES. HIGHS WEDNESDAY WILL BE 15 TO 20 DEGREES
ABOVE NORMAL...UPPER 70S OVER MOST OF THE AREA. MOISTURE WILL BE
BUILDING NORTH INTO THE TENNESSEE VALLEY AND POOLING ON THE WESTERN
SLOPES AS THE RIDGE HOLDS TIGHT THROUGH THURSDAY...INSTABILITY WILL
BE MINIMAL AND CAPPED...PROVIDING ANOTHER WARM DRY DAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S AFTER MILD MORNING LOWS IN THE LOWER 50S.
A MID LEVEL WAVE ORIGINATING IN THE SOUTHERN PLAINS WILL BE
DAMPENING THE RIDGE AMPLITUDE WITH WEAK SURFACE HIGH PRESSURE
SHIFTING OFFSHORE. THIS WILL PRODUCE A SLIGHT CHANCE OF SHOWERS
THURSDAY NIGHT...WITH A LITTLE BETTER CHANCES ON FRIDAY AS A WEAK
SURFACE FRONT EDGES VERY SLOWLY SOUTH AND EAST INTO THE MID ATLANTIC
REGION. PROGGED INSTABILITY IS SUFFICIENT FOR THUNDER GIVEN THE LOW
LEVEL FORCING AS HIGHS FRIDAY WILL STILL BE ON THE WARM SIDE...MID
TO UPPER 70S.
THE SURFACE FRONT WILL SAG FURTHER SOUTH ON SATURDAY AS LOW PRESSURE
AREA DEVELOPS OFF THE MID ATLANTIC COAST...WILL MAINTAIN SLIGHT
CHANCE TO CHANCE POPS ACROSS THE AREA THROUGH SATURDAY...AGAIN WITH
A CHANCE OF THUNDER GIVEN THE WARM AIRMASS AND POTENTIAL FOR THE
FRONT TO STALL OVER THE AREA. HIGHS WILL STILL BE IN THE MID TO
UPPER 70S.
THE FRONTS WILL BE SHOVED SOUTH OF THE AREA...SATURDAY NIGHT OR
SUNDAY AND WILL MAINTAIN SLIGHT CHANCES TO COVER THE TIMING
UNCERTAINTY. HIGH PRESSURE WILL WEDGE DOWN THE COAST SUNDAY/MONDAY
AND WILL TAPER OFF THE POPS SUNDAY NIGHT AND LEAVE MONDAY DRY FOR
NOW. HIGHS SUNDAY WILL BE IN THE LOW TO MID 70S WITH COOLER TEMPS IN
THE NORTHEAST WITH LINGERING CLOUD COVERAGE AND COOL AIR WEDGING
IN...WITH HIGHS ON MONDAY A TOUCH COOLER...LOWER 70S ACROSS THE
AREA.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 740 PM MONDAY...
VFR CONDITIONS SHOULD GRADUALLY DETERIORATE TO AT LEAST LOW MVFR
CONDITIONS OVERNIGHT IN CENTRAL NORTH CAROLINA...WITH THE GREATEST
CHANCE OF IFR CONDITIONS WITH LOW CLOUDS TOWARD THE TRIAD AND KRDU
STARTING AROUND 09Z AND CONTINUING THROUGH NEARLY TO 15Z. GUIDANCE
PROBABILITY OF THE BEST CHANCE OF SUB-MVFR CLOUDS IS IN THAT TIME
PERIOD AND IN THOSE LOCATIONS...WITH LESSER CHANCES TOWARD KFAY AND
ESPECIALLY KRWI AS IT WILL TAKE LONGER INTO THE NIGHT AND INTO THE
DAY TUESDAY TO GET INCREASING...DEEPER MOISTURE INTO THE BOUNDARY
LAYER AS SHOWN ON MODEL FORECAST SOUNDINGS. SCATTERED TO NUMEROUS
PATCHES OF LIGHT RAIN ARE ANTICIPATED LATE TONIGHT INTO TUESDAY
MORNING MOVING FROM WEST TO EAST...WITH THE AMOUNT OF CEILING HEIGHT
RISES SOMEWHAT IN QUESTION FOR TUESDAY FROM LATE MORNING INTO THE
AFTERNOON DUE TO THE AMOUNT OF LOW-LEVEL MOISTURE EXPECTED TO
REMAIN. SOME GUIDANCE SUGGESTS MORE CLEARING OF THE MVFR AND LOW VFR
LINGERING STRATOCU...BUT HAVE FORECAST THESE CONDITIONS LINGERING
DUE TO THE AMOUNT OF LOW-LEVEL MOISTURE REMAINING ON STATISTICAL
GUIDANCE AND MODEL FORECAST UPPER-AIR SOUNDINGS.
BEYOND THE 00Z VALID TAF PERIOD...PRIMARY IMPACTS ARE EXPECTED TO BE
AREAS OF FOG TUESDAY NIGHT INTO WEDNESDAY MORNING IN LINGERING
LOW-LEVEL MOISTURE AND WITH CLEARING. ANY FOG SHOULD BE MORE LOCAL
WEDNESDAY NIGHT AND THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE FRIDAY AFTERNOON INTO SATURDAY DUE TO AN UPPER-LEVEL
DISTURBANCE AND WEAK SURFACE LOW PRESSURE MOVING THROUGH THE AREA.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...KRR
SHORT TERM...VINCENT
LONG TERM...MLM
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
740 PM EDT MON MAR 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO LINGER OFFSHORE...AND EXTEND OVER
MUCH OF THE REGION...FOR A GOOD PART OF THE WORK WEEK. AN UPPER
LEVEL DISTURBANCE APPROACHES OVERNIGHT AND TUESDAY...BRINGING A GOOD
CHANCE OF SHOWERS TO THE REGION. TEMPERATURES SHOULD BE WELL ABOVE
NORMAL AT LEAST THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 215 PM MONDAY...
THIS AFTERNOON:
THE PROGRESSIVE UPPER LOW CURRENTLY IN THE NORTHERN MS RIVER VALLEY
WILL TRACK NORTHEAST INTO ONTARIO TODAY...WHILE ADDITIONAL SHORTWAVE
ENERGY CURRENTLY OVER SASKATCHEWAN/MONTANA PROGRESSES EAST TOWARD
MANITOBA. HEIGHT FALLS (ASSOC/W THE AFOREMENTIONED UPPER LOW) OVER
THE OH VALLEY/MID-ATLANTIC WILL PUSH THE H5 RIDGE OFFSHORE
TODAY...WITH INCREASINGLY WESTERLY FLOW ALOFT OVER CENTRAL NC. A
MINOR SHORTWAVE WAS PRESENT UPSTREAM OVER OKLAHOMA AT 15Z...AND IS
PROGGED TO PROGRESS EAST INTO THE WESTERN TN VALLEY BY 00Z THIS
EVENING. THE LATEST RUC MODEL DATA SHOWED A MID-LEVEL VORTICITY
MAXIMUM OVER THE DEEP SOUTH AT 15Z...APPARENTLY EMANATING FROM DEEP
CONVECTION/STRONG MID-LEVEL LATENT HEATING PRESENT OVER THE LA/MS
GULF COAST THIS MORNING...AND THE RUC SHOWS THIS FEATURE PROGRESSING
NORTHEAST INTO GA/UPSTATE SC/WESTERN NC BY 00Z THIS EVENING. IN THE
LOWER LEVELS...A 5-10 KT SOUTHERLY RETURN FLOW WILL PREVAIL OVER THE
AREA...ON THE WESTERN PERIPHERY OF THE LOW-LEVEL RIDGE AXIS NOW
CENTERED OFFSHORE THE CAROLINA COAST. W/REGARD TO PRECIP CHANCES...
LITTLE OR NO FORCING FOR ASCENT WILL BE PRESENT THIS AFTERNOON...
ASIDE FROM VERY WEAK/BROAD WARM ADVECTION ASSOC/W SOUTHERLY RETURN
FLOW. INCREASING MID/UPPER LEVEL CLOUD COVER (LIMITING INSOLATION IN
THE WEST) AND A LINGERING MID-LEVEL SUBSIDENCE INVERSION (ASSOC/W
THE DEPARTING H5 RIDGE AXIS IN THE EAST) SHOULD SIGNIFICANTLY HAMPER
ANY DIURNAL DESTABILIZATION THIS AFTERNOON...WITH VERY LITTLE OR NO
AVAILABLE INSTABILITY. AS A RESULT...EXPECT A DRY FORECAST THROUGH
00Z THIS EVENING. HIGHS WILL PRIMARILY DEPEND ON THE TIMING AND
COVERAGE OF MID/UPPER LEVEL CLOUD COVER SLOWLY PROGRESSING INTO THE
AREA FROM THE WEST. WILL FCST HIGHS RANGING FROM THE MID/UPPER 60S
(W/NW PIEDMONT) TO UPPER 60S/LOWER 70S ELSEWHERE.
TONIGHT:
UNCERTAINTY INCREASES TONIGHT...PRIMARILY WITH THE PRECIPITATION
FORECAST. FORCING FOR ASCENT OVER CENTRAL NC OVERNIGHT WILL
GENERALLY BE LIMITED TO WEAK/BROAD MID-LEVEL HEIGHT FALLS AND
LOW-LEVEL WARM ADVECTION. W/REGARD TO THERMODYNAMICS...WEAK
MID-LEVEL LAPSE RATES AND BAD DIURNAL TIMING WILL CONTRIBUTE TO VERY
LITTLE OR NO AVAILABLE INSTABILITY OVERNIGHT. THE ABOVE ALONE WOULD
ARGUE FOR VERY LITTLE OR NO CHANCE OF SHOWER ACTIVITY OVERNIGHT...
AND VIRTUALLY NO CHANCE OF THUNDER. HOWEVER...THE MID-LEVEL
VORTICITY MAXIMUM THAT DEVELOPED IN ASSOC/W DEEP CONVECTION UPSTREAM
OF THE AREA THIS MORNING IS PROGGED TO APPROACH THE WEST/SW PIEDMONT
BY ~00Z...PROGRESSING THROUGH CENTRAL NC OVERNIGHT. DESPITE POOR
THERMODYNAMICS AND WEAK BACKGROUND/SYNOPTIC ASCENT...DPVA ASSOC/W
THIS FEATURE WILL PROVIDE ADDITIONAL/FOCUSED FORCING...AND ISOLD/SCT
SHOWER ACTIVITY WILL CERTAINLY BE POSSIBLE. THE LATEST 12Z WRF-NMM
SIMULATED REFLECTIVITY PRODUCT IS MORE ROBUST THAN THE 00Z RUN IN
SHOWING SHOWER ACTIVITY DEVELOPING OVERNIGHT IN ASSOC/W THIS FEATURE.
ADDITIONALLY...THE SHORTWAVE CURRENTLY IN OKLAHOMA WILL APPROACH THE
SOUTHERN APPALACHIANS BY ~12Z TUE...AND SOME WEAK AMPLIFICATION WILL
BE POSSIBLE AS ADDITIONAL UPPER LEVEL ENERGY PROGRESSES FROM THE
DESERT SOUTHWEST INTO THE TN VALLEY. THIS COULD PROVIDE ADDITIONAL
FORCING FOR ASCENT FROM THE WEST CLOSE TO SUNRISE TUE MORNING...
ALTHOUGH THE LATEST GUIDANCE CONTINUES TO SUGGEST THE BEST FORCING
ASSOC/W THE SECOND WAVE WILL MOST LIKELY OCCUR AFTER SUNRISE...
DURING THE DAY TUE. WITH THE ABOVE IN MIND...FEEL THAT A SMALL
INCREASE IN PRECIP CHANCES IS WARRANTED OVERNIGHT...AND WILL
INDICATE A 30% CHANCE OF SHOWERS EVERYWHERE. DESPITE THE PRESENCE OF
AN UPPER LEVEL DISTURBANCE...GIVEN POOR DIURNAL TIMING AND WEAK/
INCREASINGLY MOIST ADIABATIC LAPSE RATES...LITTLE IF ANY INSTABILITY
IS EXPECTED...AND WILL LEAVE OUT MENTION OF THUNDER. WITH MOSTLY
CLOUDY OR OVERCAST SKIES...EXPECT LOWS MUCH WARMER THAN IN RECENT
DAYS...IN THE LOWER/MID 50S. -VINCENT
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM MONDAY...
TUESDAY:
AS MENTIONED IN THE NEAR TERM DISCUSSION...AN AMPLIFYING SHORTWAVE
IS EXPECTED TO PROGRESS EASTWARD ACROSS THE CAROLINAS DURING THE DAY
TUE...THOUGH THE EXACT TIMING REMAINS SOMEWHAT UNCERTAIN. IN THE
LOWER LEVELS...A PIEDMONT TROUGH DURING IS PROGGED TO DEVELOP DURING
PEAK HEATING. OTHERWISE...LIFT WILL BE CONFINED TO VERY WEAK/BROAD
LOW-LEVEL WARM ADVECTION AND MID-LEVEL HEIGHT FALLS. W/REGARD TO
THERMODYNAMICS...DESTABILIZATION WILL LIKELY BE HAMPERED BY
PERVASIVE CLOUD COVER THROUGH MUCH OF THE DAY...PARTICULARLY EAST OF
HIGHWAY 1. SOME CLEARING IS EXPECTED IN THE WEST/NW PIEDMONT BY ~18Z
IN THE PRESENCE OF A CONTINUED MOIST BOUNDARY LAYER...AND
INSTABILITY COULD ACTUALLY BE MORE FAVORABLE WEST OF HWY 1.
HOWEVER...SIGNIFICANT DRYING ALOFT IS ALSO EXPECTED AS A MUCH DRIER
MID/UPPER LEVEL AIRMASS ADVECTS INTO WESTERN PORTIONS OF THE STATE
TUE AFTERNOON...AND DRY AIR ENTRAINMENT MAY OFFSET OR COMPLETELY
NEGATE THE BENEFIT OF BETTER INSOLATION. REGARDLESS...WITH WEAK
MID-LEVEL LAPSE RATES OVER MOST OF THE AREA (ASIDE FROM WEST/NW
PIEDMONT) DURING PEAK HEATING...MLCAPE VALUES WILL LIKELY NOT EXCEED
250-500 J/KG. WITH THE ABOVE IN MIND...EXPECT SUFFICIENT FORCING AND
INSTABILITY TO WARRANT AT LEAST A LOW CHANCE (20-30%) OF SHOWERS/
STORMS...WITH THE BEST CHANCE OF THUNDER EAST OF HIGHWAY 1.
HOWEVER...IF FORCING ASSOC/W THE UPPER LEVEL WAVE IS STRONG ENOUGH
TO OVERCOME THE SIGNIFICANT AMOUNT OF DRY AIR ALOFT PROGGED IN THE
WEST/NW PIEDMONT...THUNDER WILL BE POSSIBLE THERE AS WELL. GIVEN
MARGINAL INSTABILITY...0-6 KM BULK SHEAR VALUES NO HIGHER THAN 20-25
KT (BARELY SUPPORTIVE OF MULTICELLULAR CONVECTION)...AND A
RELATIVELY SHALLOW MIXED LAYER WITH LITTLE POTENTIAL FOR
EVAPORATIVELY ENHANCED DOWNDRAFTS...DO NOT ANTICIPATE A SEVERE
THREAT WITH ANY CONVECTION. EXPECT HIGHS ON TUE TO RANGE FROM THE
UPPER 60S/LOWER 70S IN THE EAST TO THE LOWER/MID 70S IN THE WEST.
TUESDAY NIGHT:
SUBSIDENCE AND SHORTWAVE RIDGING BUILDING INTO THE AREA IN THE WAKE
OF THE SHORTWAVE SHOULD RESULT IN MOSTLY CLEAR SKIES TUE NIGHT.
GIVEN A WEAK/BAGGY MSLP GRADIENT AND THE CONTINUED PRESENCE OF A
MOIST BOUNDARY LAYER...ANTICIPATE A POTENTIAL FOR FOG ACROSS THE
AREA 06-12Z WED MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAINFALL
DURING THE DAY TUE. EXPECT LOWS IN THE LOWER/MID 50S. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...
AS SURFACE SYSTEM MOVES OFFSHORE EARLY WEDNESDAY...WARM AIR WILL BE
SPREADING NORTH DUE TO SUBTROPICAL RIDGING INTO THE SOUTHERN PLAINS
AND WESTERN GULF STATES. HIGHS WEDNESDAY WILL BE 15 TO 20 DEGREES
ABOVE NORMAL...UPPER 70S OVER MOST OF THE AREA. MOISTURE WILL BE
BUILDING NORTH INTO THE TENNESSEE VALLEY AND POOLING ON THE WESTERN
SLOPES AS THE RIDGE HOLDS TIGHT THROUGH THURSDAY...INSTABILITY WILL
BE MINIMAL AND CAPPED...PROVIDING ANOTHER WARM DRY DAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S AFTER MILD MORNING LOWS IN THE LOWER 50S.
A MID LEVEL WAVE ORIGINATING IN THE SOUTHERN PLAINS WILL BE
DAMPENING THE RIDGE AMPLITUDE WITH WEAK SURFACE HIGH PRESSURE
SHIFTING OFFSHORE. THIS WILL PRODUCE A SLIGHT CHANCE OF SHOWERS
THURSDAY NIGHT...WITH A LITTLE BETTER CHANCES ON FRIDAY AS A WEAK
SURFACE FRONT EDGES VERY SLOWLY SOUTH AND EAST INTO THE MID ATLANTIC
REGION. PROGGED INSTABILITY IS SUFFICIENT FOR THUNDER GIVEN THE LOW
LEVEL FORCING AS HIGHS FRIDAY WILL STILL BE ON THE WARM SIDE...MID
TO UPPER 70S.
THE SURFACE FRONT WILL SAG FURTHER SOUTH ON SATURDAY AS LOW PRESSURE
AREA DEVELOPS OFF THE MID ATLANTIC COAST...WILL MAINTAIN SLIGHT
CHANCE TO CHANCE POPS ACROSS THE AREA THROUGH SATURDAY...AGAIN WITH
A CHANCE OF THUNDER GIVEN THE WARM AIRMASS AND POTENTIAL FOR THE
FRONT TO STALL OVER THE AREA. HIGHS WILL STILL BE IN THE MID TO
UPPER 70S.
THE FRONTS WILL BE SHOVED SOUTH OF THE AREA...SATURDAY NIGHT OR
SUNDAY AND WILL MAINTAIN SLIGHT CHANCES TO COVER THE TIMING
UNCERTAINTY. HIGH PRESSURE WILL WEDGE DOWN THE COAST SUNDAY/MONDAY
AND WILL TAPER OFF THE POPS SUNDAY NIGHT AND LEAVE MONDAY DRY FOR
NOW. HIGHS SUNDAY WILL BE IN THE LOW TO MID 70S WITH COOLER TEMPS IN
THE NORTHEAST WITH LINGERING CLOUD COVERAGE AND COOL AIR WEDGING
IN...WITH HIGHS ON MONDAY A TOUCH COOLER...LOWER 70S ACROSS THE
AREA.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 740 PM MONDAY...
VFR CONDITIONS SHOULD GRADUALLY DETERIORATE TO AT LEAST LOW MVFR
CONDITIONS OVERNIGHT IN CENTRAL NORTH CAROLINA...WITH THE GREATEST
CHANCE OF IFR CONDITIONS WITH LOW CLOUDS TOWARD THE TRIAD AND KRDU
STARTING AROUND 09Z AND CONTINUING THROUGH NEARLY TO 15Z. GUIDANCE
PROBABILITY OF THE BEST CHANCE OF SUB-MVFR CLOUDS IS IN THAT TIME
PERIOD AND IN THOSE LOCATIONS...WITH LESSER CHANCES TOWARD KFAY AND
ESPECIALLY KRWI AS IT WILL TAKE LONGER INTO THE NIGHT AND INTO THE
DAY TUESDAY TO GET INCREASING...DEEPER MOISTURE INTO THE BOUNDARY
LAYER AS SHOWN ON MODEL FORECAST SOUNDINGS. SCATTERED TO NUMEROUS
PATCHES OF LIGHT RAIN ARE ANTICIPATED LATE TONIGHT INTO TUESDAY
MORNING MOVING FROM WEST TO EAST...WITH THE AMOUNT OF CEILING HEIGHT
RISES SOMEWHAT IN QUESTION FOR TUESDAY FROM LATE MORNING INTO THE
AFTERNOON DUE TO THE AMOUNT OF LOW-LEVEL MOISTURE EXPECTED TO
REMAIN. SOME GUIDANCE SUGGESTS MORE CLEARING OF THE MVFR AND LOW VFR
LINGERING STRATOCU...BUT HAVE FORECAST THESE CONDITIONS LINGERING
DUE TO THE AMOUNT OF LOW-LEVEL MOISTURE REMAINING ON STATISTICAL
GUIDANCE AND MODEL FORECAST UPPER-AIR SOUNDINGS.
BEYOND THE 00Z VALID TAF PERIOD...PRIMARY IMPACTS ARE EXPECTED TO BE
AREAS OF FOG TUESDAY NIGHT INTO WEDNESDAY MORNING IN LINGERING
LOW-LEVEL MOISTURE AND WITH CLEARING. ANY FOG SHOULD BE MORE LOCAL
WEDNESDAY NIGHT AND THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL
BE POSSIBLE FRIDAY AFTERNOON INTO SATURDAY DUE TO AN UPPER-LEVEL
DISTURBANCE AND WEAK SURFACE LOW PRESSURE MOVING THROUGH THE AREA.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...MLM
AVIATION...DJF
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
840 PM CDT MON MAR 12 2012
.DISCUSSION...
LAST OF THE CLOUDS CLEARING THE FAR EASTERN FCST AREA. EXPECT A
CLEAR SKY OVERNIGHT ALL AREA. WINDS DIMINISHING QUICKLY AND
OVERNIGHT WILL SEE A LOW LEVEL INVERSION SET UP WITH WINDS AT THE
SFC UNDER 10 KTS DESPITE 50 KTS AT 925 MB. GOOD RADIATIONAL
COOLING EXPECTED AND DROPPED LOWS A FEW DEGREES TO ALLOW MORE
UPPER 20S REGION WIDE. QUESTION IS FOG CHANCES IN NW/WCNTRL MN.
CLEARING OCCURRED LATE AND DRIEST OF THE AIRMASS DID NOT FILTER
IN. LIGHT WINDS AND MOIST GROUND AND LOW LEVEL INVERSION MAY SET
THE STAGE FOR PATCHY FOG OVER NW/WCNTRL MN...ESP TREED AREAS.
VSREF AND HRRR DONT SHOW WEAK TO MODERATE FOG POTENTIAL ROX-FFM
EASTWARD WITH HIGHEST CHANCES EAST AND SOUTHEAST OF FCST AREA. BUT
CHANCES THERE SO WILL INCLUDE.
&&
.PREV DISCUSSION... /ISSUED 601 PM CDT MON MAR 12 2012/
UPDATE...
WIND ADVISORY EXPIRED AT 23Z SO SEND OUT UPDATED NPW AND ZONES.
PREV DISCUSSION... /ISSUED 309 PM CDT MON MAR 12 2012/
SHORT TERM...
TIMING OF PRECIP ENDING THIS EVENING ALONG WITH TEMPERATURES
THROUGHOUT THE PERIOD WILL BE THE PRIMARY FORECAST CONCERN.
BAND OF RAIN CURRENTLY STRETCHING FROM ROSEAU TO WADENA HAS
ACCELERATED A BIT DURING THE LAST FEW HOURS AFTER HANGING OVER THE
RED RIVER VALLEY THIS MORNING. THIS HAS BEEN IN RESPONSE TO THE
NORTHERN BRANCH SHORTWAVE MOVING FROM MT INTO ND THAT HAS FINALLY
SHOVED THE MID LEVEL DEFORMATION ZONE OFF TO THE EAST. SPEED TOOLS
HAVE THE BAND EXITING THE EASTERN CWA SHORTLY BEFORE 00Z. WILL
CONTINUE TO GO DRY FOR THIS EVENING...BUT WILL TAKE A LAST LOOK
AT RADAR BEFORE FORECAST ISSUANCE AND REFINE IF NEEDED.
WESTERLY WINDS HAVE PICKED UP IN THE NORTHWESTERN CWA ON THE
BACKSIDE OF THE SFC TROUGH AND WHERE SKIES HAVE STARTED TO CLEAR.
KDVL AND MOST OF THE AWOS SITES HAVE STAYED MOSTLY BELOW WIND
ADVISORY CRITERIA. ON THE OTHER HAND...STRONG WINDS ARE JUST
OUTSIDE THE CWA AT KRUG AND K46D. A FEW OF THE ND DOT SITES HAVE
ALSO SHOWN WINDS AT CRITERIA. GOING HEADLINE GOES THROUGH 23Z AND
WILL HANG ONTO IT FOR NOW...BUT WILL KEEP AN EYE IN CASE WINDS DIE
OFF MORE THAN EXPECTED IN THE NEXT HOUR.
TONIGHT AND TOMORROW...UPPER RIDGING MOVES BACK INTO THE
AREA...WITH THE SFC TROUGH MOVING OFF TO THE EAST AND WEAK HIGH
PRESSURE BUILDING IN BRIEFLY. WEST WINDS WILL DECREASE TONIGHT AND
THEN SHIFT AROUND TO THE SOUTH. THERE IS A PRETTY GOOD AMOUNT OF
DRY AIR MOVING IN BEHIND THE SFC TROUGH...BUT WINDS SHOULD KEEP US
FAIRLY MIXED AND LOWS IN THE UPPER 20S TO LOW 30S. THE SOUTHERLY
WINDS THROUGHOUT THE DAY TOMORROW SHOULD BRING WARMER TEMPS...WITH
850MB READINGS GETTING BACK TO AROUND 12-14 C. EXACT HIGHS WILL
DEPEND ON HOW MUCH SNOW WE LOST TODAY...WHICH IS HARD TO TELL WITH
OUR CURRENT CLOUD COVER. FOR NOW KEPT HIGHS IN THE 50S WITH SOME
LOWER 60S IN THE WESTERN COUNTIES.
SOUTHWESTERLY FLOW ALOFT SETS UP FOR TUESDAY NIGHT AND CONTINUES
THROUGH THURSDAY. A WEAK SHORTWAVE MOVING FROM SASKATCHEWAN INTO
MANITOBA WILL HELP PUSH A COLD FRONT DOWN INTO THE CWA ON
WEDNESDAY. THUS TUESDAY NIGHT LOWS SHOULD BE FAIRLY MILD IN THE
30S TO LOW 40S WITH HIGHS MAINLY IN THE 50S. WINDS SHIFT BACK TO
THE SOUTH ON WEDNESDAY NIGHT AND THURSDAY AS A WEAK SFC TROUGH
SETS UP TO OUR WEST. WINDS WILL BE FAIRLY LIGHT AND THERE WILL NOT
BE A LARGE AMOUNT OF MIXING ON THURSDAY...BUT HIGHS SHOULD STILL
BE WELL ABOVE AVERAGE IN THE 50S TO LOW 60S.
LONG TERM...THURSDAY NIGHT THROUGH MONDAY
MEDIUM RANGE MODELS CONTINUE TO SHOW A SIGNIFICANT PATTERN SHIFT
THIS WEEKEND INTO EARLY NEXT WEEK AS A LARGE TROUGH ENVELOPES THE
WESTERN HALF OF THE NATION. THIS PLACES THE FORECAST AREA IN DEEP/
MOIST SOUTHWEST FLOW ALOFT AND INCREASES THE POSSIBILITY OF SHOWERS
AND THUNDERSTORMS. STILL NO REAL STRONG FORCING MECHANISM
APPARENT...SO WILL MAINTAIN PERIODS OF 20-30 POPS SATURDAY THROUGH
MONDAY. TEMPERATURES THROUGH THE PERIOD WILL REMAIN WELL ABOVE
SEASONAL NORMALS WITH PERHAPS THE FIRST 70 DEGREE READINGS ACROSS
THE SOUTHERN VALLEY BY FRIDAY/SATURDAY.
AVIATION...
THIN LINE OF LIGHT RAIN SHOWERS NOW EXTENDS FROM KROX TO KAXN AND IS
MOVING TO THE EAST AROUND 25 KTS. SOME SHOWERS ARE EXPECTED AT KBJI
OVER THE NEXT HOUR WITH DRY CONDITIONS AT ALL OTHER TAF SITES.
IFR/MVFR CLOUD DECK CLEARING LINE EXTENDS FROM KD55 TO KGWR...SUCH
THAT CEILINGS SHOULD IMPROVE TO VFR FOR VALLEY AIRFIELDS BY 21 UTC
AND BY 23 UTC AT KBJI. WINDS WILL SHIFT TO THE WEST-NORTHWEST WITH
SOME GUSTS TO 25 KTS.
HYDROLOGY...
WARM TEMPERATURES THE PAST FEW DAYS HAVE REALLY ERODED THE SNOW PACK
ACROSS THE REGION. SOME MINOR RISES HAVE ALSO BEEN SHOWING UP ON
AREA RIVERS. THE RAINFALL AND MILD TEMPERATURES TODAY WILL ALSO CUT
INTO THE REMAINING SNOW. HAVE NOT RECEIVED MANY RAINFALL REPORTS AND
NOT SURE HOW MANY OBSERVERS HAVE THEIR RAIN GAUGES OUT YET. THE ASOS
AT KFAR/KGFK REPORTED ABOUT 0.20 BUT THERE COULD BE SOME HIGHER
AMOUNTS BACK BY VALLEY CITY AND LISBON. WITH THE WARM TEMPERATURES
FORECAST THIS WEEK THE MELT PROCESS WILL CONTINUE. A RIVER STATEMENT
WAS ISSUED TODAY FOR THE RED RIVER AT WAHPETON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
319 AM CDT SUN MAR 11 2012
.SHORT TERM...TODAY THROUGH MONDAY...
LATEST WATER VAPOR IMAGERY SHOWS A BROAD SOUTHWEST FLOW ALOFT INTO
NORTH DAKOTA. CLOSED LOW ALOFT EJECTING OUT OF EASTERN NEW MEXICO
THIS MORNING IS FORECAST TO MOVE NORTHEAST...ACROSS MINNEAPOLIS
MONDAY. THIS LOW WILL PUSH A SLUG OF H85-H7 MOISTURE INTO SOUTH
CENTRAL NORTH DAKOTA SUNDAY AFTERNOON THROUGH MONDAY MORNING. MODELS
HAVE BEEN CONSISTENTLY SHOWING SOME RAIN SHOWER INTO OUR FAR
SOUTHEAST COUNTIES SUNDAY NIGHT THROUGH MONDAY MORNING. THUS HAVE
PAINTED IN A CHANCE OF RAIN IN THIS AREA WITH DRY WEATHER CONDITIONS
ELSEWHERE. A SURFACE TROUGH WILL SLIDE THROUGH WESTERN NORTH DAKOTA
TODAY WITH A WIND SHIFT TO THE NORTHWEST. THIS WILL SUPPRESS
TEMPERATURES A COUPLE DEGREES IN THE WEST FROM WHAT OCCURRED
SATURDAY...BUT OVERALL EXPECT ANOTHER WARM DAY AHEAD. BISMARCK
AND JAMESTOWN WILL REMAIN IN THE WARM SECTOR TODAY AND SHOULD
CLIMB TO NEAR RECORD HIGHS TODAY. THE FOLLOWING TABLE SHOWS
FORECAST HIGHS AND THE RECORD HIGHS FOR MARCH 11:
SITE FORECAST RECORD YEAR
WILLISTON 64 71 1990
MINOT 62 66 1990
DICKINSON 70 71 1990
BISMARCK 67 67 1934
JAMESTOWN 60 62 1934
A COLD FRONT WILL PUSH THROUGH WESTERN NORTH DAKOTA BETWEEN 06Z-
12Z MONDAY...AND INTO CENTRAL NORTH DAKOTA BETWEEN 12Z-18Z. GUSTY
NORTHWEST WINDS OF 20 TO 30 MPH WILL ENSUE BEHIND THE FRONT.
EXPECTING A DRY FRONTAL PASSAGE...BUT GUSTY WINDS AND COOLER
TEMPERATURES THROUGH MONDAY AFTERNOON.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
MEDIUM RANGE MODELS CONTINUE IN GOOD AGREEMENT WITH EXTENDED
PORTIONS OF THE FORECAST TONIGHT AND USED A BLEND OF MODELS FOR THE
GRIDS.
LARGE FLAT RIDGE REMAINS OVER CENTRAL PORTIONS OF NORTH AMERICA
THROUGH THE BEGINNING OF THE EXTENDED PERIODS. SEVERAL SHORTWAVE
SYSTEMS MOVE THROUGH OR OVER THE MEAN RIDGE POSITION...FLATTENING IT
AS IT MOVES SLOWLY EAST THROUGH THE PERIOD. BY END OF THE EXTENDED
PERIODS RIDGE IS POSITIONED ALONG THE EASTERN SEABOARD WITH A BROAD
TROUGH OVER WEST COAST AND ROCKIES.
A CUT OFF LOW IN SOUTHERN STREAM WILL EJECT INTO THE MID WEST AT THE
START OF THE EXTENDED BUT MOST EFFECTS OF THIS ENERGY WILL MISS WESTERN AND
CENTRAL NORTH DAKOTA.
LARGE SCALE SOUTHWEST FLOW EXTENDS FROM WEST COAST TO EASTERN CANADA
WITH SHORTWAVES MOVING PROGRESSIVELY THROUGH THE FLOW. LITTLE TIME
FOR MOISTURE TO BE ADVECTED NORTH AND THE EXTENDED PERIODS REMAIN
MILD AND MAINLY DRY. DAY SEVEN ALL BLEND INTRODUCES SOME LIGHT
PRECIPITATION TO THE WESTERN PORTIONS OF THE FORECAST AREA.
&&
.AVIATION...SOME MOISTURE BEGINS TO APPEAR IN THE TAFS LATE IN
PERIODS AS CUT OFF LOW OVER SOUTHWEST MOVES TOWARD THE GREAT
LAKES. NAM TIME SECTIONS BEGIN TO INTRODUCE SOME LOWER LEVEL
MOISTURE BEGINNING AFTER 00Z MONDAY. HOWEVER NUMERICAL GUIDANCE
FROM GFS AND TIME LOW LEVEL MOISTURE FORECAST FROM HRRR DO NOT
SUPPORT THIS AT LEAST IN THE FIRST PORTIONS OF THE PERIOD AND WILL
CONTINUE VFR FORECAST IN TAFS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KS
LONG TERM....HW
AVIATION...HW
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1243 AM EST SUN MAR 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL PUSH EAST OF THE AREA TONIGHT AND REMAIN
OFFSHORE THE EASTERN SEABOARD FOR SEVERAL DAYS. A WEAK FRONT WILL
BRUSH THE REGION ON MONDAY NIGHT BRINGING A CHANCE OF SHOWERS.
OTHERWISE... THE COMING WEEK WILL BE FAIR AND UNSEASONABLY WARM.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
DESPITE CLEAR SKIES AND LOW DEWPOINTS...TEMPS SLOW TO FALL
TONIGHT DUE TO A DEVELOPING SW BREEZE. HRRR AND RUC GUIDANCE
INDICATE LITTLE CHANGE IN TEMPS BTWN 05Z-12Z WITH READINGS
AVERAGING IN THE L30S BY DAWN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
A RAPID WARM UP IS IN STORE SUNDAY...AS THE SURFACE HIGH MOVES
EAST OF THE AREA AND MILDER RETURN SOUTHWEST FLOW ADVECTS MUCH
WARMER AIR ALOFT. EVEN WITHOUT IDEAL MIXING...THE ABUNDANT
SUNSHINE...COMBINED WITH 850 MB TEMPS INCREASING TO 5C SHOULD
TRANSLATE TO HIGHS IN THE UPPER 50S AND LOWER 60S. AS PREVIOUS
SHIFT NOTED...THESE HIGHS COULD BE AT LEAST A FEW DEG F TOO COOL
ACROSS THE CENTRAL VALLEYS AND SUSQ VALLEY...SHOULD MIXING DEEPEN
ENOUGH TO TAP THE WARMER AIR ALOFT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS WE HAVE SEEN FOR THE LAST FEW DAYS...THE LONG TERM MODELS AND
GENERAL PATTERN LEAD A HIGH CONFIDENCE FORECAST OF VERY WARM
TEMPERATURES AND NORMAL TO BELOW NORMAL RAINFALL. THE LONG WAVE
RIDGE IN PLACE AS WE START THE PERIOD WILL BE WEAKENED SLIGHTLY
BY A COUPLE OF SYSTEMS ROLLING OFF TO OUR NORTH.
STRONG SFC ANTICYCLONE - A BERMUDA HIGH - OFF KHAT WILL DIRECT THE
FIRST SYSTEM WELL TO THE NORTH OF THE AREA MONDAY NIGHT. THE
THINNING MOISTURE RIBBON OF /INITIALLY/ 1 INCH PWATS ALONG OF THE
WARM FRONT WILL LEAD TO A SLUG OF WARM ADVECTIVE RAIN/SHOWERS.
TIMING FOR SHOWERS WOULD BE MONDAY AFTN/EVENING. INSTABILITY PROGS
YIELD BARELY MARGINAL LI/S EXIST AS IT MOVES THROUGH...BUT ELEVATED
THUNDER POSSIBLE IN THE WEST. ALL THIS IS WELL-COLLABORATED AMONG
THE VARIOUS MODELS AND ENSEMBLE MEMBERS. DRYING BEHIND THE FIRST
SYSTEM MAY TAKE A DAY OR SO WITH MOIST SWRLY FLOW AT THE SFC IN THE
WARM SECTOR. SCT SHRA EXPECTED ON TUES AS THE LEADING EDGE OF COOLER
- BUT STILL ABNORMALLY MILD - AIR MOVES DOWN FROM THE GREAT LAKES.
RIDGE ALOFT IS FLATTENED A BIT BUT REBOUNDS QUICKLY WITH THE AXIS
OVER THE CENTRAL US AND UPPER GREAT LAKES. THE BERMUDA HIGH WEAKENS
AND GETS DISPLACED TO THE SOUTH BUT THEN REBOUNDS AND THE LLVL FLOW
REMAINS DECIDEDLY S/SW. THE SECOND AND VERY WEAK UPPER SHORT WAVE IS
A TINY TAIL FROM A SYSTEM THAT GOES OVER HUDSON BAY. THE SHORT WAVE
TROUGH GETS LOST IN THE VERY HIGH HEIGHTS OVER THE BULK OF THE
CONUS. BUT ENOUGH FORCING AND INFLOW FROM THE WESTERN GULF EXISTS
THURS/FRI TO KEEP A VERY LOW CHC OF PRECIP IN FOR THE END OF THE
WEEK...BUT MOST OF THE TIME WILL BE DRY BETWEEN TUESDAY AND
SATURDAY/DAY 7 AS THE RIDGE SLIDES TO THE EAST. FAIRLY HIGH
CONFIDENCE FOR THE LAST DAY OF A 7-DAY FORECAST. DEEP LONG-WAVE
TROUGH IN THE WEST AND OUR BIG RIDGE OVERHEAD WILL KEEP THE HIGHEST
MOISTURE TO OUR WEST. WILL DRAW A LOW CHC OF PRECIP IN FOR SAT
SINCE THE SWRLY FLOW ALOFT AND HIGH MOISTURE MAY BE ABLE TO FORM A
WEAK SFC TROUGH OVER THE MS/OH VALLEYS AND BRING SCT SHOWERS TO THE
REGION.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE ANCHORED ALONG THE SRN MID-ATLC COAST WILL YIELD TO
AN APPROACHING FRONTAL SYSTEM BY MON AFTN. THIS SYSTEM MAY BRING
REDUCED FLYING CONDS LATER MONDAY INTO TUESDAY WITH OCNL -SHRA.
HIGH PRES RETURNS FOR MID TO LATE WEEK WITH MAINLY VFR CONDS XPCD.
OUTLOOK...
MON NGT-TUE...CHC OF SHRA/REDUCED CIGS MAINLY N-W MTNS.
WED-THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...DANGELO
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1228 AM EST SUN MAR 11 2012
.SYNOPSIS...
HIGH PRESSURE WILL PUSH EAST OF THE AREA TONIGHT AND REMAIN OFF OF
THE EASTERN SEABOARD FOR SEVERAL DAYS. A WEAK FRONT WILL BRUSH THE
REGION ON MONDAY NIGHT BRINGING A CHANCE OF SHOWERS. OTHERWISE...
THE COMING WEEK WILL BE FAIR AND UNSEASONABLY WARM.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
DESPITE CLEAR SKIES AND LOW DEWPOINTS...TEMPS SLOW TO FALL
TONIGHT DUE TO A DEVELOPING SW BREEZE. HRRR AND RUC GUIDANCE
INDICATE LITTLE CHANGE IN TEMPS BTWN 05Z-12Z WITH READINGS
AVERAGING IN THE L30S BY DAWN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
A RAPID WARM UP IS IN STORE SUNDAY...AS THE SURFACE HIGH MOVES
EAST OF THE AREA AND MILDER RETURN SOUTHWEST FLOW ADVECTS MUCH
WARMER AIR ALOFT. EVEN WITHOUT IDEAL MIXING...THE ABUNDANT
SUNSHINE...COMBINED WITH 850 MB TEMPS INCREASING TO 5C SHOULD
TRANSLATE TO HIGHS IN THE UPPER 50S AND LOWER 60S. AS PREVIOUS
SHIFT NOTED...THESE HIGHS COULD BE AT LEAST A FEW DEG F TOO COOL
ACROSS THE CENTRAL VALLEYS AND SUSQ VALLEY...SHOULD MIXING DEEPEN
ENOUGH TO TAP THE WARMER AIR ALOFT.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS WE HAVE SEEN FOR THE LAST FEW DAYS...THE LONG TERM MODELS AND
GENERAL PATTERN LEAD A HIGH CONFIDENCE FORECAST OF VERY WARM
TEMPERATURES AND NORMAL TO BELOW NORMAL RAINFALL. THE LONG WAVE
RIDGE IN PLACE AS WE START THE PERIOD WILL BE WEAKENED SLIGHTLY
BY A COUPLE OF SYSTEMS ROLLING OFF TO OUR NORTH.
STRONG SFC ANTICYCLONE - A BERMUDA HIGH - OFF KHAT WILL DIRECT THE
FIRST SYSTEM WELL TO THE NORTH OF THE AREA MONDAY NIGHT. THE
THINNING MOISTURE RIBBON OF /INITIALLY/ 1 INCH PWATS ALONG OF THE
WARM FRONT WILL LEAD TO A SLUG OF WARM ADVECTIVE RAIN/SHOWERS.
TIMING FOR SHOWERS WOULD BE MONDAY AFTN/EVENING. INSTABILITY PROGS
YIELD BARELY MARGINAL LI/S EXIST AS IT MOVES THROUGH...BUT ELEVATED
THUNDER POSSIBLE IN THE WEST. ALL THIS IS WELL-COLLABORATED AMONG
THE VARIOUS MODELS AND ENSEMBLE MEMBERS. DRYING BEHIND THE FIRST
SYSTEM MAY TAKE A DAY OR SO WITH MOIST SWRLY FLOW AT THE SFC IN THE
WARM SECTOR. SCT SHRA EXPECTED ON TUES AS THE LEADING EDGE OF COOLER
- BUT STILL ABNORMALLY MILD - AIR MOVES DOWN FROM THE GREAT LAKES.
RIDGE ALOFT IS FLATTENED A BIT BUT REBOUNDS QUICKLY WITH THE AXIS
OVER THE CENTRAL US AND UPPER GREAT LAKES. THE BERMUDA HIGH WEAKENS
AND GETS DISPLACED TO THE SOUTH BUT THEN REBOUNDS AND THE LLVL FLOW
REMAINS DECIDEDLY S/SW. THE SECOND AND VERY WEAK UPPER SHORT WAVE IS
A TINY TAIL FROM A SYSTEM THAT GOES OVER HUDSON BAY. THE SHORT WAVE
TROUGH GETS LOST IN THE VERY HIGH HEIGHTS OVER THE BULK OF THE
CONUS. BUT ENOUGH FORCING AND INFLOW FROM THE WESTERN GULF EXISTS
THURS/FRI TO KEEP A VERY LOW CHC OF PRECIP IN FOR THE END OF THE
WEEK...BUT MOST OF THE TIME WILL BE DRY BETWEEN TUESDAY AND
SATURDAY/DAY 7 AS THE RIDGE SLIDES TO THE EAST. FAIRLY HIGH
CONFIDENCE FOR THE LAST DAY OF A 7-DAY FORECAST. DEEP LONG-WAVE
TROUGH IN THE WEST AND OUR BIG RIDGE OVERHEAD WILL KEEP THE HIGHEST
MOISTURE TO OUR WEST. WILL DRAW A LOW CHC OF PRECIP IN FOR SAT
SINCE THE SWRLY FLOW ALOFT AND HIGH MOISTURE MAY BE ABLE TO FORM A
WEAK SFC TROUGH OVER THE MS/OH VALLEYS AND BRING SCT SHOWERS TO THE
REGION.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL PROVIDE VFR CONDS FOR THE NEXT FEW DAYS. LIGHT
WINDS WILL BECOME SOUTHWEST ON SUNDAY. NO SIGNIFICANT WEATHER
UNTIL MONDAY EVENING.
OUTLOOK...
MON NGT-TUE...CHC OF SHRA/REDUCED CIGS MAINLY NW MTNS. WED-
THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...FITZGERALD
SHORT TERM...DEVOIR/FITZGERALD
LONG TERM...DANGELO
AVIATION...DEVOIR/CERU
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1055 PM CST SAT MAR 10 2012
.DISCUSSION.../ISSUED AT 850 PM CST/
ALLOWED RED FLAG WARNING TO EXPIRE AS PLANNED WITH WINDS DIMINISHING
AND RH VALUES CLIMBING AS SURFACE TEMPERATURES COOLED. OTHER THAN
FRESHENING UP THE GRIDS...FORECAST LOOKS TO BE ON TRACK WITH MINOR
UPDATES OUT.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
TONIGHT...VFR CONDITIONS WILL PREVAIL. HOWEVER THERE ARE SOME NON
CONVECTIVE LOW LEVEL WIND SHEAR CONCERNS IN OUR NORTHWESTERN ZONES...
WHICH INCLUDES THE HURON TAF. ALTHOUGH THE LOW LEVEL JET WILL REMAIN
STRONG EVERYWHERE IN OUR FORECAST AREA...OUR NORTHWEST ZONES WILL
SEE THE MOST DECOUPLING AT THE SURFACE CREATING FAIRLY LIGHT
WINDS...AND THUS THE MOST LOW LEVEL WIND SHEAR. OTHERWISE ON
SUNDAY...AN UPPER LEVEL LOW WILL MOVE NORTHWARD. MVFR CONDITIONS
WILL LIKELY ENCROACH IN ALONG AND EAST OF I 29 AS THE DAY PROGRESSES
ON SUNDAY...WITH RAIN CHANCES IN THE MID AND LATE AFTERNOON
THROUGHOUT THAT SAME AREA. ON SUNDAY EVENING...MVFR IN RAIN WILL
MOVE THROUGH MUCH OF THE FORECAST AREA...ESPECIALLY EAST OF THE
JAMES RIVER.
&&
.PREV DISCUSSION.../ISSUED AT 300 PM CST/
ADDED LAST FIRE WEATHER ZONE TO RED FLAG WARNING PRIOR TO 19Z...AS
SOUTHERN PARTS OF THAT ZONE WERE ALSO FALLING TO BELOW 25 PERCENT RH
AND WINDS THERE GUSTING TO NEAR 25 MPH OR SLIGHTLY HIGHER. NORTHERN
PARTS OF THAT ZONE NOT LIKELY TO HIT RED FLAG CRITERIA...BUT LATEST
OBS ARE SHOWING RH VALUES AT KHON FLIRTING WITH 25 PERCENT AS OF 20Z
AS WELL. DEW POINTS HAVE BEEN SLOWLY CLIMBING ACROSS OUR SD COUNTIES
AS THE HRRR ALLUDED TO ON ITS EARLIER RUNS...WHICH LENDS CONFIDENCE
TO USING THIS FOR SOME GUIDANCE THROUGH THE EVENING HOURS. INCREASED
DEW POINTS NOT ENOUGH TO RAISE RELATIVE HUMIDITY SIGNIFICANTLY IN
OUR SOUTHWEST THOUGH...AS TEMPS WARMING INTO THE LOWER TO MID 70S
ARE KEEPING RH VALUES AT OR BELOW 20 PERCENT. SOUTHWEST MINNESOTA
NOT YET DOWN TO 25 PERCENT BUT GETTING VERY CLOSE AS OF 20Z AND
STRONGEST WINDS STILL SEEN IN THAT AREA WITH GUSTS TO 35+MPH MUCH OF
THE AFTERNOON. SO ALL IN ALL LOOKS LIKE A GOOD RED FLAG WARNING
THROUGHOUT THE AREA THIS AFTERNOON.
AS FOR TONIGHT...EXPECT DEW POINTS TO JUMP A BIT AND WIND GUSTS TO
DROP OFF WITH SUNSET...SO EXPIRATION OF RED FLAG WARNING AT 6PM
LOOKS OK. SOUTHERLY FLOW SHOULD STAY FAIRLY STEADY IN 10-15MPH MOST
AREAS TONIGHT. SLIGHTLY HIGHER SOUTH-SOUTHWEST WINDS IN HIGHER
ELEVATIONS...BUT NOT EXPECTED TO BE AS STRONG AS LAST NIGHT AS LOW
LEVEL JET NOT AS STRONG ACROSS THIS AREA. THE MODEST WINDS AND SOME
INCREASE IN LOW LEVEL MOISTURE WITH MORE SOUTHERLY LOW LEVEL FETCH
WILL HOLD TEMPS UP A BIT FROM LAST NIGHT...AND HAVE BUMPED LOWS UP A
FEW DEGREES INTO THE LOWER TO MID 40S.
APPROACH OF UPPER LOW SUNDAY WILL BRING INCREASING CLOUDS AND LOW
LEVEL MOISTURE. STILL THE INITIAL INTRUSION OF SHOWERS ALOFT WILL
HAVE TROUBLE GETTING TO THE SURFACE AND WILL CONTINUE TO LEAVE
PRECIPITATION OUT OF THE MORNING. OTHERWISE EXPECT THE UPPER LOW AND
ITS HALF DECENT DYNAMICS TO COMBINE WITH THE INCREASING MOISTURE
AND MEAGER THERMAL SUPPORT TO PRODUCE A HIGH PROBABILITY/ LOW QPF
EVENT OF RAIN FOR OUR EASTERN FORECAST AREA...THOUGH NOT SO LOW THAT
A TENTH OF AN INCH OR TWO COULD NOT BE SPIT OUT. A FEW LIGHT SHOWERS
MAY GET INTO THE WEST ALSO. TIMING IS MAINLY SUNDAY NIGHT...WITH
SYSTEM MOVING OUT STEADILY MONDAY AND DRY OVER THE AREA BY NOON. MID
AND DRY WEATHER EXPECTED FROM MONDAY AFTERNOON THROUGH MOST OF THE
FORECAST PERIOD WHICH GOES INTO THE COMING WEEKEND. STEADILY
INCREASING LOW LEVEL MOISTURE WILL PUMP UP LOW TEMPERATURES WHILE
DAYTIME HIGHS ARE IN THE 60S AND 70S. BASICALLY MID TO LATE APRIL
WEATHER. AS MAJOR TROUGH DIGS OVER THE WEST COAST THERE COULD BE A
WEAK WAVE OR TWO COME UP AHEAD OF TROUGH IN SOUTHWESTERLY UPPER
FLOW. ACCORDINGLY HAVE MENTIONED A CHANCE OF THUNDERSTORMS FOR
SATURDAY. THIS IS AHEAD OF MAIN SYSTEM AND THE DRY WARM SPELL COULD
GO THROUGH THE WEEKEND. HOWEVER THE AIR WILL BE GETTING MORE
UNSTABLE IN ADDITION TO THE MOISTURE INCREASE...SO THE GUIDANCE
INDICATION OF PRECIPITATION THREAT WILL BE FOLLOWED FOR NOW. THREAT
OF SIGNIFICANT SYSTEM AND SEVERE WEATHER EVENT CONTINUES TO BE
BEYOND FORECAST PERIOD AS 00Z GFS RUN WAS NOT ACCEPTED HERE.
/WILLIAMS
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
903 PM EDT MON MAR 12 2012
.SYNOPSIS...
A VERY WEAK COLD FRONT WILL DRIFT SLOWLY TOWARD OUR AREA THROUGH
TONIGHT AND PASS ACROSS OUR REGION TUESDAY AFTERNOON AND EVENING.
HIGH PRESSURE WILL CONTROL OUR WEATHER PATTERN FOR WEDNESDAY AND
MUCH OF THURSDAY...WHILE ANOTHER WEAK COLD FRONT WILL APPROACH THE
REGION ON FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 835 PM EDT MONDAY...
SCATTERED SHOWERS ALONG WITH PATCHY LIGHT RAIN CONTINUE TO DRIFT NE
ACROSS THE REGION THIS EVENING IN ADVANCE OF THE FRONT ALOFT WEST
OF THE MOUNTAINS. LATEST EVENING RAOBS SHOW RATHER DEEP MOISTURE AS
PLUME OF HIGHER PWATS...PER BLENDED TPW DEPICTION...SLIDES ACROSS
AIDED BY WEAK ISENTROPIC LIFT. THIS WILL LIKELY BE ENOUGH TO KEEP
BANDS OF -SHRA GOING FOR A WHILE LONGER WITH SCTD SHRA COVERAGE
THRU LATE THIS EVENING...AND LOW CHANCES AFTER MIDNIGHT. THIS IN
LINE WITH THE LATEST HRRR WHICH SEEMS BEST IN SHIFTING A FINAL
BROKEN AREA OF SHRA NOW TO THE WEST ACROSS THE REGION THRU THE
OVERNIGHT. HOWEVER SINCE EXPECT A BIT OVERDONE GIVEN WEAK LIFT AND
LITTLE SUPPORT ALOFT...WILL KEEP POPS MAINLY CHANCE AND W/OUT ANY
THUNDER MENTION PER LACK OF ANY INSTABILITY OFF MSAS. OTRW LOTS OF
CLOUDS TO LINGER OVERNIGHT WHICH SHOULD KEEP TEMPS QUITE MILD WITH
MOST OUTSIDE OF THE VALLEYS STAYING IN THE 50 TO 55 RANGE.
PREVIOUS DISCUSSION AS OF 340 PM EDT MONDAY...
RADAR IMAGERY INDICATES SHOWERS MAKING THEIR WAY NORTHEAST ACROSS
OUR AREA FROM THE NORTH CAROLINA MOUNTAINS THROUGH THE ALLEGHANY
HIGHLANDS THIS AFTERNOON. RAINFALL HAS BEEN LIGHT FOR THE MOST
PART...AND EXPECT THE SHOWER ACTIVITY TO REMAIN THAT WAY INTO THE
OVERNIGHT HOURS. RAINFALL WILL SPREAD EAST THROUGH THE EVENING...
WITH MOST LOCATIONS ACROSS OUR REGION OBSERVING SOME RAINFALL BY
MIDNIGHT.
WITH SOUTHWESTERLY WINDS AND ABUNDANT CLOUD COVER ACROSS THE AREA
OVERNIGHT...TEMPERATURES WILL REMAIN ON MILD SIDE. EXPECT OVERNIGHT
LOW TEMPERATURES TO RANGE FROM THE UPPER 40S TO THE LOWER 50S
AREAWIDE. THE MAIN AREA OF RAINFALL WILL TRANSITION FROM SOUTHEAST
WEST VIRGINIA...THE ALLEGHANY HIGHLANDS AND THE SHENANDOAH VALLEY
TONIGHT...INTO THE PIEDMONTS BY SUNRISE TUESDAY MORNING.
LOOKING INTO TUESDAY AFTERNOON...THE UPPER LEVEL PORTION OF THE
LOW PRESSURE SYSTEM TRIGGERING OUR SHOWER ACTIVITY WILL BE
PASSING EAST OF OUR AREA BY LATE MORNING...CAUSING SHOWER ACTIVITY
ACROSS THE PIEDMONTS TO DIMINISH BY NOON. HOWEVER...WILL EXPECT A
COLD FRONT TO PASS ACROSS OUR AREA DURING THE AFTERNOON AND
EVENING. WHILE THIS COLD FRONT IS WEAK...CANNOT RULE OUT THE
POSSIBILITY OF A FEW SHOWERS AND ISOLATED THUNDERSTORMS DEVELOP
AHEAD OF THE BOUNDARY...ESPECIALLY ACROSS THE PIEDMONT. BUT WITH
LITTLE UPPER ATMOSPHERIC SUPPORT TO THIS ACTIVITY...DO NOT EXPECT
ANY THUNDERSTORMS TO BECOME SEVERE AS THE COLD FRONT PASSES.
AFTERNOON HIGH TEMPERATURES WILL CONTINUE TO BE QUITE WARM...WITH
HIGHS RANGING FROM UPPER 60S WEST...TO THE MID 70S EAST.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 155 PM EDT MONDAY...
ANTICIPATE PRECIPITATION ASSOCIATED WITH THE COLD FRONTAL PASSAGE
TO BE SOUTHEAST OF THE REGION BY TUESDAY NIGHT. AS SUCH...WILL
CONTINUE WITH A DRY FORECAST FOR THIS TIME FRAME...BUT KEEP THE
TREND OF MORE CLOUDS IN THE EVENING GIVING WAY TO CLEARING THROUGH
THE NIGHT.
WEDNESDAY THROUGH THURSDAY AN UPPER RIDGE OF HIGH PRESSURE WILL BUILD
ACROSS THE REGION WHILE DISTURBANCE RIDGE ALONG THE NORTHERN EXTENT
OF THE RIDGE NEAR THE U.S./CANADIAN BORDER. WILL HAVE A DRY AND MILD
FORECAST THROUGH THIS PERIOD WITH 850 MB TEMPS INCREASING TO AROUND
+12 C BY THURSDAY. ANTICIPATING HIGHS IN THE UPPER 70S TO 80 DEGREES
EAST OF THE BLUE RIDGE WITH A MIX OF LOWER AND MID 70S ACROSS THE
MOUNTAINS BY THIS DAY. MOISTURE WILL BEGIN TO POOL ON THE WEST SIDE
OF THE SURFACE HIGH BY THURSDAY AFTERNOON AND HEAD NORTH INTO THE
OHIO VALLEY. WE MAY SEE SOME ISOLATED SHOWERS OR THUNDERSTORMS
ACROSS SE WV THURSDAY AFTERNOON IN ASSOCIATION WITH THIS MOISTURE
AND THE INFLUENCE OF THE TROUGH RIDING ALONG THE CREST OF THE RIDGE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 1047 AM EDT MONDAY...
THURSDAY NIGHT THROUGH FRIDAY...AN UPPER RIDGE WILL BE PARKED OVER
THE APPALACHIANS. CONCURRENTLY...AN AREA OF LOW PRESSURE WILL BE
MOVING ACROSS THE GREAT LAKES REGION. THIS SYSTEMS ASSOCIATED WARM
FRONT WILL EXTEND SOUTHEAST THROUGH PENNSYLVANIA. THIS PATTERN WILL
ALLOW FOR A MILD AND MOIST SOUTHERLY FLOW TO HEAD NORTH INTO THE
OHIO VALLEY...AND AS THE LOW MAKES ITS WAY EASTWARD...SO TOO WILL
THIS MOISTURE AND INSTABILITY INTO OUR FORECAST AREA. WE ARE
EXPECTING SCATTERED SHOWERS TO ARRIVE IN THE WEST THURSDAY
NIGHT...WITH BETTER COVERAGE ACROSS THE ENTIRE REGION ON
FRIDAY...ALONG WITH THE POTENTIAL FOR THUNDERSTORMS.
BY SATURDAY...THE LOW ACROSS THE GREAT LAKES WILL HAVE MOVED OVER
NEW ENGLAND...AND HIGH PRESSURE WILL BUILD IN BEHIND THE LOW AND ITS
ASSOCIATED FRONTAL BOUNDARIES. THIS INTERACTION WILL REVERSE THE
PREVIOUS WARM FRONT INTO A WEAK BACKDOOR FRONT THAT WILL APPROACH
THE REGION ON SATURDAY. THIS SCENARIO KEEPS THE MILD AND MOIST AIR
OVER OUR REGION ON SATURDAY...BUT ALSO MAINTAINS A FOCUS FOR
ADDITIONAL NIGHTTIME SHOWERS AND DAYTIME SHOWERS AND STORMS FRIDAY
NIGHT INTO SATURDAY.
SATURDAY NIGHT INTO SUNDAY...THE BACKDOOR FRONT SINKS SOUTH THROUGH
THE REGION AND WE BEGIN THE ONSET OF A PERIOD OF COLD AIR DAMMING.
ANTICIPATE THE SURFACE HIGH TO BECOME CENTERED OVER NEW ENGLAND AND
NOSE SOUTH ALONG THE LEE OF THE APPALACHIANS. TEMPERATURES WILL
TREND COOLER...WITH CLOUD COVER AND SCATTERED SHOWERS LINGERING.
THUNDERSTORMS STILL MAY BE POSSIBLE ALONG THE WESTERN SECTIONS OF
THE FORECAST AREA THAT WILL BE OUTSIDE THE INFLUENCE OF THE WEDGE.
MONDAY IS LOOKING LIKE A QUESTIONABLE DAY. SOME MODELS ARE MORE
PROGRESSIVE IN RETURNING SOUTHERLY FLOW TO THE AREA AND ERODING THE
WEDGE. OTHERS VEER THE LOW LEVEL WINDS MORE EASTERLY WITH AN
ATLANTIC FETCH THAT WOULD HELP TO MAINTAIN...IF NOT STRENGTHEN THE
CLOUDY AND COOL CONDITIONS IN THE EAST. OUR FORECAST WILL REFLECT
THE LATTER OF THESE TWO SCENARIOS GIVEN MODEL TENDENCY TO ERODE
WEDGES QUICKER THAN REALITY TURNS OUT TO BE.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
AS OF 750 PM EDT MONDAY...
SHOWERS WILL BE SPOTTY AT BEST OVERNIGHT WITH CIGS LOWERING.
GUIDANCE CONTINUES TO INDICATE A FEW HRS OF IFR CIG NEAR
DAWN...BUT WILL CONTINUE WITH JUST A SCT DECK BELOW 1KFT.
KLWB/KBLF STAND THE BEST CHC OF EXPERIENCING IFR CIGS...AS SHOWERS
HAVE BEEN MORE NUMEROUS THERE FOR MUCH OF TODAY. ANY IFR CIGS
SHOULD BE BRIEF WITH CIGS RISING DURING THE MORNING HOURS.
SHOWER ACTIVITY IS EXPECTED TO LINGER ACROSS THE EASTERN HALF OF
THE AREA THROUGH LATE TUESDAY AFTERNOON BEFORE FINALLY MOVING
AWAY. WE CAN EXPECT MAINLY VFR CONDITIONS WEDNESDAY THROUGH
FRIDAY...ALTHOUGH WE CANNOT RULE OUT SOME SCATTERED SHOWERS MAINLY
IN THE WEST...AS MOIST SOUTHERLY FLOW REDEVELOPS ONCE HIGH
PRESSURE MOVES EAST OF THE AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...NF
NEAR TERM...JH/NF
SHORT TERM...DS
LONG TERM...DS
AVIATION...KM/NF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
656 PM CDT MON MAR 12 2012
...NEAR OR ABOVE RECORD HIGHS EXPECTED THROUGHOUT MUCH OF THE
FORECAST...
.SHORT TERM...TONIGHT THROUGH THURSDAY
303 PM CDT MON MAR 12 2012
CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT
ANALYSIS SHOWED SOUTHWEST FLOW FROM THE PACIFIC NORTHWEST TO
HUDSON BAY... WITH A SHORTWAVE TROUGH OVER SASKATCHEWAN. IN THE
SOUTHERN STREAM...AN UPPER LOW WAS NEAR EAU CLAIRE WITH A
SHORTWAVE ROUNDING ITS BASE OVER NORTHERN ILLINOIS. THIS LATTER
SHORTWAVE IS HELPING TO SUSTAIN SHOWERS AND A FEW THUNDERSTORMS
OVER SOUTHEAST WISCONSIN AND NORTHERN ILLINOIS...AIDED BY DAYTIME
HEATING. OTHER SHOWER ACTIVITY WAS OVER NORTHERN AND CENTRAL
WISCONSIN...AIDED BY DPVA FORCING AHEAD OF THE UPPER LOW. ANOTHER
AREA OF SHOWERS WERE WEST OF MINNEAPOLIS IN THE DEFORMATION ON THE
BACK SIDE OF THE UPPER LOW. THERE HAS BEEN SOME PARTIAL CLEARING
TODAY SOUTH OF I-90...THANKS TO DRY AIR WRAPPING AROUND THE UPPER
LOW. THIS CLEARING COMBINED WITH A WARM LAST NIGHT HAS ALLOWED
TEMPERATURES TO CLIMB MOSTLY INTO THE 50S...DESPITE 850MB TEMPS
WHICH HAVE DROPPED TO 2-4C PER RUC ANALYSIS...AND THE 3C READING
AT OAX AT 12Z. MUCH WARMER AIR AT 850MB EXISTS OVER THE
DAKOTAS...THOUGH...WITH READINGS OF 12C AT BIS AND UNR AT 12Z.
TONIGHT AND TUESDAY...THE UPPER LOW OVER WESTERN WISCONSIN IS
PROGGED TO CONTINUE ITS NORTHEASTWARD TREK...LIFTING INTO NORTHEAST
ONTARIO BY 12Z TUESDAY. IT APPEARS THIS UPPER LOW WILL THEN SLOW
DOWN...DUE TO THE CURRENT SHORTWAVE TROUGH IN SASKATCHEWAN WHICH
MODELS HAVE IT PHASING WITH THE UPPER LOW. THE ONLY IMPACTS THIS
PHASING HAS ON OUR FORECAST AREA IS NORTH OF I-94 TUESDAY
MORNING...WHERE SLIGHTLY COOLER AND DRIER AIR WILL MOVE IN.
OTHERWISE...850MB TEMPS ARE PROGGED TO BE ON THE RISE THROUGHOUT
THIS TIME PERIOD. AT 12Z TUESDAY...THEY SHOULD RANGE FROM
4-8C...THEN RISE TO 8-12C BY 00Z WEDNESDAY. THIS WARMING COMBINED
WITH CLEARING SKIES AND DRIER AIR FOR TUESDAY SHOULD RESULT IN
DECENT MIXING. STAYED TOWARD THE HIGH END OF GUIDANCE FOR HIGHS
WHICH PUTS THEM CLOSE TO OR ABOVE RECORD VALUES. REGARDING TONIGHTS
LOWS...PRECIPITABLE WATER VALUES ARE FORECAST TO DROP TO 0.25 INCH
BY 12Z OR LOWER AFTER BEING UP BETWEEN 0.5-0.75 INCHES. THIS DRY AIR
SHOULD HELP TEMPERATURES DROP...THOUGH WINDS KIND OF STAY UP THROUGH
MUCH OF THE NIGHT UNTIL LATE. THEREFORE HAVE TAKEN A BLEND OF
GUIDANCE APPROACH. COULD HAVE SOME PATCHY FOG WHERE WINDS CAN
DECOUPLE DUE TO RECENT RAINS...WHILE THE OVERALL WIND ESPECIALLY
RIGHT ABOVE THE SURFACE KEEPS THE FOG FROM BECOMING MORE WIDESPREAD.
TUESDAY NIGHT THROUGH THURSDAY...A BIG CHUNK OF THE UPPER TROUGHING
CURRENTLY OFF THE PACIFIC NORTHWEST COAST IS FORECAST TO LIFT OUT
INTO SOUTHWEST CANADA TUESDAY NIGHT...THEN UP TO HUDSON BAY BY
WEDNESDAY NIGHT. A STRONG LOW PRESSURE SYSTEM DEVELOPS FROM THIS
UPPER TROUGHING...THOUGH AGAIN WELL OFF TO OUR NORTH. HOWEVER...
THERE ARE GOING TO BE SOME IMPACTS FROM IT. FIRST...A SURGE OF WARM
AIR CAUSED BY DOWNSLOPING OFF THE ROCKIES WILL MOVE INTO THE AREA.
THE FIRST FEELING OF THIS COMES TUESDAY NIGHT AS INCREASING
SOUTHEAST TO SOUTH WINDS BRING HIGHER DEWPOINTS AND 850MB TEMPS RISE
TO 12-14C. THIS SITUATION MAY KEEP TEMPERATURES FROM FALLING BELOW
50 ALONG AND WEST OF THE MISSISSIPPI RIVER. ON WEDNESDAY...WINDS
TURN SOUTHWEST AHEAD OF THE LOW PRESSURE SYSTEMS COLD FRONT
CROSSING MINNESOTA. THERE ARE INDICATIONS FROM THE 12.12Z NAM/ECMWF
THAT 850MB TEMPS COULD EVEN RISE TO 16C OVER NORTHEAST IOWA...ALMOST
3 STANDARD DEVIATIONS ABOVE NORMAL. WITH PLENTY OF SUN AND A WARM
START...TEMPERATURES SHOULD EASILY CLIMB INTO THE 70S. AN 80F
READING MAY EVEN OCCUR (NOTE 81F HIGH FOR SPARTA OFF MET GUIDANCE).
DEWPOINTS ARE ALSO EXPECTED TO CLIMB INTO THE 50S WITH A GOOD FETCH
COMING OUT OF THE GULF OF MEXICO. THE COMBINATION OF THE
UNPRECEDENTED WARMTH AND DEWPOINTS WILL LIKELY LEAD TO CUMULUS
DEVELOPMENT...MAKING IT FEEL MORE LIKE LATE SPRING THAN MID MARCH.
FOR WEDNESDAY NIGHT INTO THURSDAY...THE UPPER FLOW TURNS A LITTLE
MORE TOWARDS WEST...ENOUGH TO ALLOW THE WEAKENING COLD FRONT TO MOVE
INTO THE FORECAST AREA. BELIEVE THE 12.12Z NAM IS TOO AGGRESSIVE ON
THE SPEED GIVEN THE 12.12Z GFS/UKMET/ECMWF SLOWER. IN ANY EVENT...
THE FRONT WILL RE-ORIENT ITSELF WEST-EAST...LIKELY OCCURRING ON
THURSDAY NEAR OR JUST SOUTH OF I-90. CONVECTIVE INITIATION ON THE
FRONT DOES NOT SEEM LIKELY...DUE TO CAPPING. THE 12.12Z GFS DOES TRY
TO SPIT OUT THESE VERY LIGHT QPF VALUES...BUT THIS IS MORE FROM THE
MODEL BRINGING IN TOO MUCH LOW LEVEL MOISTURE AND GENERATING
STRATUS/DRIZZLE VERSUS CONVECTION. EVEN THEN...THE PATTERN DOES NOT
FAVOR STRATUS/DRIZZLE AND THE MODEL SEEMS TO HAVE A HIGH MOISTURE
BIAS. EVEN WITH THE FRONTAL PASSAGE...850MB TEMPS ONLY DROP TO
10-12C SO THURSDAY MAY ONLY END UP A LITTLE COOLER THAN WEDNESDAY.
WEDNESDAY NIGHT ALSO LIKELY STAYING MILD...ESPECIALLY AHEAD OF THE
FRONT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
303 PM CDT MON MAR 12 2012
MAIN STORY REMAINS THE UNPRECEDENTED WARMTH WHICH LOOKS TO PERSIST
THROUGH THE ENTIRE LONG TERM PERIOD AND BEYOND.
VERY GOOD MODEL AGREEMENT EXISTS THAT A DEEP UPPER LEVEL TROUGH IS
GOING TO DEVELOP ALONG THE WEST COAST OF THE U.S. FRIDAY INTO
SATURDAY. AS A RESULT...RIDGING BUILDS DOWNSTREAM OVER THE CENTRAL
AND EASTERN U.S.. THIS RIDGE BECOMES QUITE STRONG AND ACCORDING TO
THE CFS V2 MODEL...IT MAY PERSIST RIGHT THROUGH THE END OF THE
MONTH...WHILE THE WEST COAST TROUGH STAYS PUT OR CUTS-OFF. SINCE THE
CFS HAS BEEN DOING VERY WELL OVER THE PAST FEW MONTHS...HAVE
PREFERRED MODEL SCENARIOS WHICH KEEP THE WESTERN TROUGH IN
PLACE...WHICH LUCKILY MOST MODELS DO INCLUDING THE NEW 12.12Z ECMWF.
FOLLOWING THIS IDEA...850MB TEMPS THROUGHOUT THE LONG TERM PERIOD
STAY BETWEEN 10-14C OR 2-2.5 STANDARD DEVIATIONS ABOVE NORMAL. THIS
WOULD MEAN HIGHS NEAR OR ABOVE RECORD HIGHS. HAVE ADJUSTED ALL HIGH
TEMPERATURES TOWARDS THE HIGH END OF GUIDANCE. A PERSISTENT SOUTH
WIND OF 20-40 KT AT 925MB WILL HELP TO KEEP A PULL OF MOISTURE OUT
OF THE GULF OF MEXICO...THOUGH LACK OF VEGETATION AND THE DISTANCE
FROM THE GULF SHOULD HOLD DEWPOINTS BELOW 60. WITH THE WARM
TEMPERATURES AND DEWPOINTS...ANTICIPATING A LOT OF PARTLY SUNNY DAYS
DUE TO CUMULUS DEVELOPMENT.
PRECIPITATION CHANCES ARE VERY UNCERTAIN AND IT IS ENTIRELY POSSIBLE
THAT THE WHOLE LONG TERM PERIOD ENDS UP DRY. HOWEVER...WITH THE WELL
ABOVE NORMAL DEWPOINTS INTERACTING WITH WEAK SHORTWAVES COMING OUT
OF THE PACIFIC THROUGH THE BUILDING RIDGING...CANNOT RULE OUT A FEW
PERIODS OF SHOWERS AND THUNDERSTORMS. HAVE 20-30 PERCENT CHANCES
THROUGHOUT MUCH OF THE LONG TERM AS A RESULT. MUST BE STRESSED THAT
MUCH OF THIS PERIOD WILL LIKELY BE DRY.
&&
.AVIATION...TONIGHT AND TUESDAY
656 PM CDT MON MAR 12 2012
RADAR/SATELLITE SHOW A BAND OF SHOWERS/MVFR CUMULUS AND
STRATOCUMULUS //ASSOCIATED WITH EXITING UPPER LEVEL LOW OVER UPPER
MI// EXTENDING FROM NORTH CENTRAL MN SOUTHEASTWARD INTO SOUTHEAST
MN/SOUTHWEST WI...INCLUDING THE KRST/KLSE TAF SITES. BACK EDGE OF
THESE CLOUDS AND EMBEDDED SCATTERED -SHRA ACTIVITY WILL EXIT EAST
OF KRST AROUND 03Z AND KLSE AROUND 04Z AS THE LOW CONTINUES TO
MOVE EAST OF THE REGION AND HIGH PRESSURE BUILDS IN FROM THE
NORTHERN PLAINS. CLEAR SKIES EXPECTED AFTER THAT. STILL SOME
QUESTION FOR SOME FOG FORMATION UNDER THE RIDGE AXIS IN THE
MORNING IN THE 10-14Z TIME FRAME. MODELS INDICATE LIGHT STIRRING
OF THE WINDS FROM THE WEST WHICH WOULD INHIBIT WIDESPREAD FOG
FORMATION...BUT CANNOT RULE OUT AREAS OF FOG WHERE THE WIND DECOUPLES.
WILL CONTINUE THE 6SM BR AT THE KRST TAF SITES IN THE 10-14Z TIME
FRAME AND CONTINUE TO MONITOR THE SITUATION CLOSELY THIS EVENING/OVERNIGHT.
OTHERWISE...SKC/P6SM CONDITIONS EXPECTED THROUGH TUESDAY WITH
WEST/SOUTHWEST WINDS OF 5-10KT BACKING TO THE SOUTH LATER IN THE
AFTERNOON ON THE BACKSIDE OF THE HIGH PRESSURE RIDGE AXIS.
&&
.CLIMATE...THROUGH EARLY NEXT WEEK
303 PM CDT MON MAR 12 2012
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGHOUT MUCH OF THE
NEXT 7 DAYS AND LIKELY BEYOND. AT LA CROSSE AND ROCHESTER...THE NEXT
3 DAYS APPEAR TO BE RELATIVE MINIMUMS FOR WHAT THE GOING RECORDS
ARE...SO ANY OF THE DAYS WILL HOLD A CHANCE FOR BREAKING THE RECORD.
WEDNESDAY STILL LOOKS LIKE THE WARMEST DAY OF THE WEEK AND HOLDS THE
HIGHEST POTENTIAL FOR BREAKING THE RECORDS WITH HIGHS EXPECTED IN
THE 70S. A FEW PLACES COULD EVEN APPROACH 80. HEADING INTO THE
WEEKEND AND EARLY NEXT WEEK...RECORDS VARY IN TERMS OF HOW HIGH THEY
ARE...BUT DEFINITELY POTENTIAL EXISTS FOR MORE RECORDS TO BE BROKEN.
SEE OUR WEBSITE FOR A LISTING OF RECORD HIGHS THROUGH EARLY NEXT
WEEK.
&&
.HYDROLOGY...
1232 PM CDT MON MAR 12 2012
ACCORDING TO OFFICIALS THERE HAVE BEEN SOME LOCALIZED ICE BLOCKAGES
ALONG THE BLACK RIVER FROM AROUND THE NEILLSVILLE AREA DOWN TO THE
UPPER PORTION OF LAKE ARBUTUS NEAR HATFIELD. REPORTS INDICATE THAT
THERE ARE LARGE BLOCKS OF ICE MOVING DOWN THE RIVER...AND THEY ARE
OCCASIONALLY GETTING HUNG UP ON RIVER BENDS AND WHERE ROCKS CAUSE
CONSTRICTIONS IN THE RIVER.
AT THIS POINT...IT DOES NOT APPEAR THERE IS A LARGE RISK FOR
FLOODING DUE TO ICE JAMS. BUT THERE IS A RISK FOR RAPID WITHIN-BANK
RISES ALONG THE BLACK RIVER DUE TO THIS ICE ACTION. WE HAVE ALREADY
SEEN SOME RISES ON THE RIVER MONITORING GAUGES IN THAT AREA.
THERE IS STILL SOME SNOW COVER OVER THE HEADWATER OF THE BLACK RIVER
BASIN...FROM WITHEE UP TO MEDFORD. WITH THE WARM TEMPERATURES
EXPECTED THIS WEEK...THAT SNOW IS EXPECTED TO MELT AND RUNOFF
QUICKLY INTO THE RIVER. THE ICE THAT REMAINS IN THE RIVER IS
EXPECTED TO BREAK UP AND MOVE DOWNSTREAM...SO WATER LEVELS WILL NEED
TO BE MONITORED THIS WEEK AS THAT COMBINATION WILL LEAD TO HIGHER
WATER ALONG THE BLACK RIVER THIS WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
303 PM CDT MON MAR 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
CLIMATE...AJ
HYDROLOGY...MW
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
255 PM CDT SUN MAR 11 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
255 PM CDT SUN MAR 11 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION TONIGHT INTO MONDAY AS
WELL AS THE ABOVE NORMAL TEMPERATURES THROUGHOUT.
CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED AN UPPER TROUGH FROM THE NORTHEAST PACIFIC INTO THE PACIFIC
NORTHWEST...THEN ZONAL FLOW FROM MANITOBA EAST INTO QUEBEC. IN THE
SOUTHERN STREAM...AN UPPER LOW WAS OVER THE OKLAHOMA PANHANDLE WITH
RIDGING BUILDING DOWNSTREAM INTO THE UPPER MISSISSIPPI RIVER VALLEY
REGION. AHEAD OF THE UPPER LOW...SHOWERS AND EMBEDDED THUNDERSTORMS
EXTENDED FROM FAR SOUTHWEST IOWA INTO KANSAS...MISSOURI AND SOUTH TO
THE GULF COAST. THE PRECIPITATION WAS BEING FORCED FROM A NUMBER OF
FACTORS: DPVA AHEAD OF THE UPPER LOW THE BIG ONE...A STREAM OF LOW
LEVEL MOISTURE TRANSPORT NOTED BY 30-40 KT 925-850MB WINDS ON
PROFILER DATA...INSTABILITY PRODUCED BY DAYTIME HEATING ACTING WITH
THE UPPER LOW AND SURFACE DEWPOINTS CLIMBING INTO THE 40S AND 50S.
PRECIPITABLE WATER VALUES IN THE MOISTURE STREAM ARE 1-1.5 INCHES OR
200-270 PERCENT OF NORMAL PER 12Z RAOBS. OVER THE FORECAST
AREA...DRY AIR ON THE 12Z MPX AND DVN SOUNDINGS HAVE KEPT ANY CLOUD
COVERAGE AHEAD OF THE PRECIPITATION LIMITED TO CIRRUS AND MID-LEVEL
CLOUDS THUS FAR...AND THESE ARE JUST COMING INTO LOCATIONS ALONG AND
SOUTH OF I-90. WITH PLENTY OF SUN...850MB TEMPS BETWEEN 8-10C PER
12Z RAOB ANALYSIS AND A RELATIVELY BREEZY SOUTH WIND...TEMPERATURES
HAVE CLIMBED AGAIN INTO THE 60S TODAY.
TONIGHT AND MONDAY...UPPER LOW OVER THE CENTRAL PLAINS IS FORECAST
TO LIFT NORTHEAST...CROSSING THE AREA SHORTLY AFTER 12Z MONDAY...
THEN REACH LAKE SUPERIOR BY 00Z TUESDAY. THIS EJECTION IS IN
RESPONSE TO THE TROUGHING CURRENTLY OVER THE PACIFIC NORTHWEST
LIFTING INTO MANITOBA. PRETTY IMPRESSIVE 500MB HEIGHT FALLS PROGGED
TONIGHT INTO MONDAY MORNING...ANYWHERE BETWEEN 150 AND 200 METERS.
SO NEEDLESS TO SAY THE DYNAMIC FORCING IS REALLY STRONG. A STRONG
SURGE OF MOISTURE COMES UP AHEAD OF THE LOW...SEEN IN PRECIPITABLE
WATER PROGS OF AROUND 1 INCH OR 300 PERCENT OF NORMAL. THEREFORE...
THE DYNAMICS SHOULD HAVE NO PROBLEM BRINGING PRECIPITATION TO THE
AREA. DESPITE THE ABOVE NORMAL MOISTURE...NOT ANTICIPATING THIS TO
BE A HEAVY QPF EVENT FOR A NUMBER OF REASONS: THE HIGH AMOUNT OF
MOISTURE DOES NOT STICK AROUND LONG DUE TO THE UPPER LOW MOVING
QUICKLY...MUCAPE FROM THE NAM FOR MUCH OF THIS TIME PERIOD STAYS
BELOW 200 J/KG LIMITING THUNDERSTORMS TO ISOLATED AT BEST...NO UPPER
JET SUPPORT AND BEST 850MB MOISTURE TRANSPORT AIMED EAST OF HERE.
WHAT INSTABILITY DOES EXIST IS OVER WISCONSIN DURING THE DAY
MONDAY...THUS HAVE KEPT A SLIGHT CHANCE FOR THUNDER THEN. REGARDING
PRECIPITATION TRENDS IN THE FORECAST...SHOULD SEE SHOWERS MOVE IN
THIS EVENING OVER MUCH OF THE FORECAST AREA...THEN BECOME MORE
SCATTERED ON MONDAY AS THE UPPER LOW PULLS AWAY BUT ITS COLD POOL
ALOFT LINGERS. TEMPERATURES ARE LIKELY TO REMAIN MILD TONIGHT WITH
CLOUDS AND HIGHER DEWPOINTS MOVING IN. LITTLE CHANGE REQUIRED FOR
LOWS. HIGHS ON MONDAY ARE TRICKY GIVEN THAT ONLY SUN POTENTIAL WOULD
OCCUR IN THE AFTERNOON AND SOUTH OF I-90. FOR NOW STUCK WITH A BLEND
OF GUIDANCE...BUT IF CLOUDS STAY AROUND LONGER THAN FORECAST...HIGHS
MAY NEED TO BE COOLED.
MONDAY NIGHT THROUGH WEDNESDAY...UPPER LOW IS PROGGED TO MOVE
FURTHER AWAY FROM THE REGION WHILE A FEW NEW TROUGHS DROP DOWN INTO
THE PACIFIC NORTHWEST AND EJECT UP INTO CENTRAL CANADA. THE RESPONSE
OF ALL OF THIS IS TO BUILD RIDGING OVER THE UPPER MISSISSIPPI RIVER
VALLEY REGION...SENDING A SURGE OF WARMER AIR INTO THE FORECAST
AREA. 850MB TEMPS WHICH START OFF AT 4-8C AT 12Z TUESDAY ARE
FORECAST TO CLIMB TO 8-12C BY 00Z WEDNESDAY AND TO 12-14C FOR THE
WHOLE DAYTIME HOURS ON WEDNESDAY. THERE ARE EVEN SOME HINTS OF 16C
850MB TEMPS APPROACHING THE WESTERN PORTION OF THE FORECAST AREA ON
WEDNESDAY...AHEAD OF A DYING SURFACE COLD FRONT COMING INTO
MINNESOTA. THESE 850MB READINGS ARE 2-2.5 STANDARD DEVIATIONS ABOVE
NORMAL...FAVORING TEMPERATURES APPROACHING OR EXCEEDING RECORD HIGHS
GIVEN TOO THAT PLENTY OF SUN SHOULD OCCUR BOTH DAYS. LEANED TOWARDS
THE HIGH END OF ALL GUIDANCE AS A RESULT FOR HIGHS. SOME
PRECIPITATION NOTES. THE 11.12Z NAM SHOWS ELEVATED CONVECTION
BETWEEN 09-15Z WEDNESDAY OVER EASTERN IOWA AND FAR SOUTHWEST
WISCONSIN. THIS PRECIPITATION FORMS DUE TO THE PRESENCE OF A WEAK
SHORTWAVE...A WARM FRONT AND ELEVATED CAPE VALUES BETWEEN 1000-1500
J/KG. HOWEVER...THE 850MB DEWPOINT HELPING TO PRODUCE THIS CAPE IS
AROUND 10C...OR 8C HIGHER THAN THE ECMWF. THE GFS IS ALSO SLIGHTLY
LOWER. THEREFORE AM DISCOUNTING THE NAM AT THE PRESENT TIME. ON
WEDNESDAY...THE GFS SEEMS TO HAVE TOO MUCH MOISTURE AT AND BELOW
900MB...A KNOWN PROBLEM SEEN IN SOME RECENT WARM EVENTS...AND THUS
STRATUS AND DRIZZLE OUT. DISCOUNTING THIS SCENARIO AS WELL SINCE IT
DOES NOT AGREE WITH THE ECMWF/NAM/CANADIAN. LASTLY...ON WEDNESDAY
AFTERNOON THE NAM CONVECTS OVER EASTERN IOWA AND SOUTHERN
WISCONSIN...THOUGH THERE IS NO SURFACE TRIGGER. IN ADDITION...THE
MODEL BRINGS SURFACE DEWPOINTS INTO THE 60S WHICH SEEMS WAY TOO
HIGH. AS SUCH...HAVE FOLLOWED THE DRY ECMWF/CANADIAN SCENARIO.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
255 PM CDT SUN MAR 11 2012
GOOD MODEL AGREEMENT EXISTS THAT THE FLOW OF TROUGHS COMING INTO THE
PACIFIC NORTHWEST THEN LIFTING INTO NORTH CENTRAL CANADA PERSISTS
THROUGH THURSDAY NIGHT. THEN ON FRIDAY AND HEADING INTO THE
WEEKEND...ALL MODELS SHOW A REALLY DEEP TROUGH FORMING ALONG THE
WEST COAST OF THE U.S. THE 11.12Z GFS IS BY FAR THE MOST PROGRESSIVE
WITH A STRONG SHORTWAVE COMING OUT OF THIS TROUGH...RESULTING IN A
FRONT MOVING THROUGH THE AREA AT 12Z SUNDAY. THE 11.00Z/12Z ECMWF
AND 11.12Z CANADIAN KEEPS THIS SHORTWAVE WRAPPED IN THE TROUGH WHICH
SEEMS MORE REASONABLE. BASICALLY ALL THIS MEANS IS THAT THE FORECAST
AREA STAYS UNDER UPPER RIDGING AND IN THE WARM SECTOR. THERE IS ONE
POTENTIAL CAVEAT TO THE WARM SECTOR WHICH IS THE COLD FRONT FROM
WEDNESDAY OVER MINNESOTA. MODELS PROG THIS FRONT TO DIE AS IT COMES
INTO THE FORECAST AREA WEDNESDAY NIGHT AND THURSDAY...WHILE BECOMING
ORIENTED MORE WEST-EAST WITH THE UPPER FLOW. AT THIS TIME HAVE
MAINTAINED A CONSENSUS 20 PERCENT CHANCES FOR PRECIPITATION ON THUS
FRONT OVER SOUTHWEST WISCONSIN WEDNESDAY NIGHT...THEN IN NORTHEAST
IOWA ON THURSDAY. STILL...THINKING MUCH OF THIS PERIOD WILL END UP
DRY. AFTER THIS...IT BECOMES A LITTLE MORE DIFFICULT TO PINPOINT
WHEN PRECIPITATION OCCURS. AS THE UPPER LEVEL FLOW AMPLIFIES...THERE
ARE INDICATIONS OF A FEW SHORTWAVES RIDING THROUGH DURING THE FRIDAY
THROUGH SATURDAY NIGHT TIME PERIOD. DEPENDING ON THE MODEL THE
TIMING VARIES. FOR NOW HAVE STAYED WITH A CONSENSUS APPROACH WHICH
RESULTS IN MUCH OF THE FORECAST AREA HAVING 20-40 PERCENT CHANCES.
STRONGER UPPER RIDGING ON SUNDAY SHOULD PREVENT ANY PRECIPITATION.
THE MAIN STORY CONTINUES TO BE THE WARMTH. 850MB TEMPS ON AVERAGE
HOLD BETWEEN 10-14C...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL.
THIS SHOULD HELP TO KEEP HIGH TEMPERATURES MOSTLY IN THE 70S AND
NEAR OR ABOVE RECORDS. PERHAPS THE ONLY EXCEPTION TO THIS MIGHT BE
ON THURSDAY OVER NORTH CENTRAL WISCONSIN ON THE NORTH SIDE OF THAT
DYING COLD FRONT. ALSO OF NOTE IS THAT LOW TEMPERATURES ARE GOING TO
BE VERY WARM FOR THIS TIME OF YEAR TOO...AIDED BY DEWPOINTS HOLDING
MAINLY IN THE 50S. IN FACT...LOWS COULD BE 10-15 DEGREES ABOVE
NORMAL HIGHS.
&&
.AVIATION...THROUGH 18Z MONDAY
1234 PM CDT SUN MAR 11 2012
MAIN FORECAST CONCERN IS LOW PRESSURE OVER THE CENTRAL PLAINS TO
LIFT NORTHWARD INTO THE GREAT LAKES REGION AND SPREAD CLOUDS INTO
THE AREA AFTER 00Z MONDAY. THE LATEST 11.12Z NAM AND RUC BUFKIT
SOUNDINGS SHOW THE ATMOSPHERE COLUMN SATURATING THIS AFTERNOON AND
EVENING...AS LIFT IN ASSOCIATION WITH LOW PRESSURE MOVES OVER THE
RST AND LSE TAF SITES. BOTH THE DETERMINISTIC MODELS INDICATE
CEILINGS LOWERING INTO THE LIFR/IFR AT BOTH THE TAF SITES AFTER 03Z
MONDAY AND CONTINUE THESE CONDITIONS INTO MONDAY MORNING. NEXT
CONCERN IS THE 11.12Z NAM IS INDICATING WEAK ELEVATED INSTABILITY OF
100 TO 300 J/KG MOST UNSTABLE CAPE AT THE 0-6KM LAYER MAINLY ALONG
AND EAST OF THE MISSISSIPPI RIVER AFTER 15Z MONDAY. WITH
THIS...THERE IS THE POSSIBILITY OF AN ISOLATED THUNDERSTORM
EAST OF THE MISSISSIPPI RIVER AFTER 12Z MONDAY. FOR NOW...WILL NOT
MENTION ANY THUNDERSTORM AT BOTH TAF SITES...DUE TO CONFIDENCE OF A
THUNDERSTORM OCCURRING AT ANY GIVEN LOCATION IS LOW.
&&
.CLIMATE...
255 PM CDT SUN MAR 11 2012
RECORD HIGHS HAVE BEEN BROKEN AT KLSE AND KRST...JUST BARELY WITH
ONLY BEING 1 DEGREE ABOVE THEM...BUT RECORDS NONETHELESS. POTENTIAL
STILL EXISTS FOR A DEGREE OR TWO RISE SO RECORD EVENT REPORTS WILL
BE HELD UNTIL DAYTIME HEATING ENDS AROUND 5 PM.
BEING NEAR OR AT RECORDS FOR HIGHS WILL BE THE NORM HERE STARTING
TUESDAY AND LASTING PERHAPS INTO EARLY NEXT WEEK. AN ANOMALOUS WARM
PATTERN IS SETTING UP OVER THE FORECAST AREA. LOW TEMPERATURES COULD
EVEN BE HIGH ENOUGH THAT WE SET NEW RECORD HIGH MINIMUMS. SEE OUR
WEBSITE FOR DETAILS ON RECORD HIGHS.
&&
.HYDROLOGY...THROUGH MONDAY
255 PM CDT SUN MAR 11 2012
NOT MUCH IN THE WAY OF ANY CHANGES TO THE GOING FORECAST. SNOWPACK
IN TAYLOR COUNTY IS IN FULL MELT MODE NOW / PER NOHRSC SNOW PACK
TEMPERATURE ANALYSIS / AND WILL CONTINUE TO MELT DURING THE NEXT
COUPLE OF DAYS. FORECAST RAINFALL AMOUNTS ARE STILL IN THE 0.35 TO
0.60 INCH RANGE WHICH WILL LIKELY LEAD TO SOME RISES ALONG THE
BLACK AND TREMPEALEAU RIVERS...BUT STILL NOT UP TO FLOOD STAGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CDT SUN MAR 11 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DTJ
CLIMATE...AJ
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1234 PM CDT SUN MAR 11 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
317 AM CDT SUN MAR 11 2012
THE MAIN STORIES IN THE SHORT TERM ARE WITH THE RAIN CHANCES
TONIGHT INTO MONDAY FOLLOWED BY THE QUICK RETURN OF WARM AIR TO
THE REGION TUESDAY AND WEDNESDAY.
CLEAR SKIES WERE IN PLACE THROUGHOUT THE REGION WITH BROAD RIDGING
ALOFT STRETCHING ACROSS MUCH OF THE US WITH A CUT OFF LOW STARTING
TO PROGRESS EASTWARD OUT OF THE FOUR CORNERS REGION. AT THE
SURFACE...A BROAD TROUGH OF LOW PRESSURE STRETCHES ALONG THE LEE
OF THE ROCKIES WHILE A RIDGE OF HIGH PRESSURE EXTENDS ALONG THE
ATLANTIC COAST. THE PRESSURE GRADIENT BETWEEN THESE TWO FEATURES
HAS RELAXED AND HAS ALLOWED FOR WIND SPEEDS TO WEAKEN OVERNIGHT
THOUGH STILL REMAIN GUSTY AT TIMES TO BETWEEN 20 TO 25KTS IN
SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THE INITIAL FOCUS IS ON THE CUTOFF LOW TO THE SOUTH AND WHEN ITS
IMPACTS WILL REACH THE REGION. UPPER LEVEL CLOUD COVER IS ALREADY
ON THE DOOR STEP OF SOUTHWEST IOWA WITH THESE CLOUDS EXPECTED TO
LIFT INTO THE REGION LATER THIS MORNING AS THE LOW CONTINUES TO
PROPAGATE NORTHEAST OUT OF THE SOUTHWEST. THESE UPPER LEVEL CLOUDS
WILL THICKEN THROUGH THE DAY...BUT THE DEEPER LOW LEVEL MOISTURE
WILL NOT GET IN UNTIL TONIGHT AS THE BETTER FORCING COMES IN JUST
AHEAD OF THE LOW. EVERYTHING COMES TOGETHER TONIGHT AS THE LOW
GETS INTO THE CENTRAL PLAINS WITH THE COMBINATION OF STRONG LOW
LEVEL MOISTURE TRANSPORT AND MID LEVEL QG FORCING COMING IN AT THE
SAME TIME FROM THE SOUTH. THIS SHOULD LEAD TO A BAND OF RAIN
LIFTING NORTHWARD ACROSS THE REGION OVERNIGHT BEFORE REACHING
NORTHERN WISCONSIN MONDAY MORNING. SCATTERED SHOWERS WILL THEN
PERSIST INTO MONDAY AS THE CORE OF THE LOW MOVES THROUGH WITH
LAPSE RATES STEEPENING THROUGH THE LOW TO MID LEVELS. THESE
STEEPENING LAPSE RATES MAY LEAD TO SOME VERY SKINNY CAPE
DEVELOPING ACROSS THE EASTERN HALF OF THE FORECAST AREA ON
MONDAY...MAINLY ALONG AND EAST OF THE MISSISSIPPI...PARTICULARLY
IF ANY BREAKS IN THE CLOUDS ALLOW FOR SURFACE TEMPERATURES TO
WARM. THE 11.00Z NAM AND GFS BOTH SHOW THIS WITH THEIR FORECAST
SOUNDINGS...SO HAVE ADDED AN ISOLATED THUNDER MENTION TO THE
FORECAST FOR MONDAY.
AFTER THIS SYSTEM EXITS THE REGION BY MONDAY EVENING...A RIDGE OF
HIGH PRESSURE WILL MOVE THROUGH ON TUESDAY WITH WARMER AIR COMING
BACK INTO THE REGION AS THIS RIDGE COMES IN. 850MB TEMPERATURE
ANOMALIES SHOW STANDARD DEVIATIONS OF +1 TO +2 ABOVE THE NORM
TUESDAY INTO WEDNESDAY...WHICH WOULD MEAN LEANING CLOSER TOWARD
NEAR RECORD HIGHS THAN AWAY FROM THEM. THUS...HAVE KEPT THE UPPER
60S TO LOWER 70S GOING FOR THESE DAYS. THE COLD FRONT THAT HAD
PREVIOUSLY BEEN PROGGED TO COME THROUGH THE REGION ON WEDNESDAY
NOW APPEARS TO HANG UP TO THE WEST WITH NOT MUCH OF A CHANCE FOR
RAIN SHOWERS TO FORM ALONG IT.
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY NIGHT
317 AM CDT SUN MAR 11 2012
NO END IN SIGHT FOR THE WARM TREND WITH IT EXPECTED TO GO THROUGH
THE REST OF THE WEEK AND NEXT WEEKEND AS SOUTHWESTERLY FLOW ALOFT
PERSISTS. THIS WILL KEEP TEMPERATURES WELL ABOVE NORMAL AND
CLOSE TO RECORD BREAKING THROUGH THIS TIME FRAME. RAIN CHANCES
ARE A LITTLE TOUGHER TO PIN DOWN WITHOUT ANY SYSTEMS COMING
THROUGH TO FOCUS THE LIFT...THOUGH THE 11.00Z GFS SUGGESTS THAT
THE 925-850MB MOISTURE TRANSPORT WILL BE ANGLED NORTHWARD FROM THE
GULF TOWARD THE REGION AND MAY BE ENOUGH TO POP OFF SOME SHOWERS
AND THUNDERSTORMS. DETAILS WILL HAVE TO BE WORKED OUT AS WE GET
CLOSER TO THIS TIME FRAME BUT THERE IS AT LEAST ENOUGH OF A CHANCE
TO WARRANT SOME SMALL PRECIPITATION CHANCES FRIDAY INTO SATURDAY
NIGHT.
&&
.AVIATION...THROUGH 18Z MONDAY
1234 PM CDT SUN MAR 11 2012
MAIN FORECAST CONCERN IS LOW PRESSURE OVER THE CENTRAL PLAINS TO
LIFT NORTHWARD INTO THE GREAT LAKES REGION AND SPREAD CLOUDS INTO
THE AREA AFTER 00Z MONDAY. THE LATEST 11.12Z NAM AND RUC BUFKIT
SOUNDINGS SHOW THE ATMOSPHERE COLUMN SATURATING THIS AFTERNOON AND
EVENING...AS LIFT IN ASSOCIATION WITH LOW PRESSURE MOVES OVER THE
RST AND LSE TAF SITES. BOTH THE DETERMINISTIC MODELS INDICATE
CEILINGS LOWERING INTO THE LIFR/IFR AT BOTH THE TAF SITES AFTER 03Z
MONDAY AND CONTINUE THESE CONDITIONS INTO MONDAY MORNING. NEXT
CONCERN IS THE 11.12Z NAM IS INDICATING WEAK ELEVATED INSTABILITY OF
100 TO 300 J/KG MOST UNSTABLE CAPE AT THE 0-6KM LAYER MAINLY ALONG
AND EAST OF THE MISSISSIPPI RIVER AFTER 15Z MONDAY. WITH
THIS...THERE IS THE POSSIBILITY OF AN ISOLATED THUNDERSTORM
EAST OF THE MISSISSIPPI RIVER AFTER 12Z MONDAY. FOR NOW...WILL NOT
MENTION ANY THUNDERSTORM AT BOTH TAF SITES...DUE TO CONFIDENCE OF A
THUNDERSTORM OCCURRING AT ANY GIVEN LOCATION IS LOW.
&&
.CLIMATE...TODAY
317 AM CDT SUN MAR 11 2012
THE COMBINATION OF ABUNDANT SUNSHINE THIS MORNING...SOUTH WINDS IN
THE 10 TO 15 KNOT RANGE...AND AN UNUSUALLY WARM START TO THE DAY
/TEMPERATURES ARE STILL RANGING FROM AROUND 40 TO THE LOWER 50S/
WILL RESULT IN THE MAXIMUM TEMPERATURES ONCE AGAIN APPROACHING
RECORD LEVELS TODAY. THE RECORD MAXIMUM TEMPERATURES FOR TODAY ARE
IN THE UPPER 50S NORTH OF THE INTERSTATE 94 CORRIDOR...AND IN THE
LOWER AND MID 60S ELSEWHERE. IN MOST CASES...THEY WERE ESTABLISHED
IN 1977...1990...AND 2006.
&&
.HYDROLOGY...THROUGH MONDAY
317 AM CDT SUN MAR 11 2012
NOT MUCH IN THE WAY OF ANY CHANGES TO THE GOING FORECAST...THOUGH
SOME ISOLATED THUNDERSTORMS DO APPEAR POSSIBLE ON MONDAY. THERE
STILL IS A HEALTHY SNOW PACK OF UP TO A FOOT ACROSS NORTHERN
CLARK INTO TAYLOR COUNTIES WHICH WILL CONTINUALLY ERODE THROUGH
THE EARLY PART OF THE UPCOMING WEEK. FORECAST RAINFALL AMOUNTS ARE
STILL IN THE 0.25 TO 0.50 INCH RANGE WHICH WILL LIKELY LEAD TO
SOME RISES ALONG THE BLACK AND TREMPEALEAU RIVERS...BUT STILL NOT
UP TO FLOOD STAGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
317 AM CDT SUN MAR 11 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DTJ
CLIMATE...BOYNE
HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1101 PM CST SAT MAR 10 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY
252 PM CST SAT MAR 10 2012
MAIN FORECAST CONCERNS ARE ON THE EXPECTED PRECIPITATION SUNDAY
NIGHT AND MONDAY...ALONG WITH TEMPERATURES THROUGHOUT.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED THE MAIN BELT OF THE WESTERLIES TRAVERSING FROM THE PACIFIC
NORTHWEST INTO SOUTH CENTRAL CANADA...THEN DOWN INTO TROUGHING OVER
NEW ENGLAND. HOWEVER...IN THE SOUTHERN STREAM...AN UPPER LOW WAS
PRESENT OVER NEW MEXICO WITH RIDGING BUILDING UP AHEAD OF IT OVER THE
MISSISSIPPI RIVER VALLEY. MOISTURE SO FAR AHEAD OF THIS UPPER LOW
HAS ADVECTED INTO OKLAHOMA...NOTED BY SHOWERS...LOWER LEVEL STRATUS
AND DEWPOINTS IN THE LOW TO MID 30S. A MUCH DIFFERENT SITUATION
EXISTS ACROSS THE UPPER MIDWEST INTO OUR REGION...THOUGH. 12Z
SOUNDINGS FROM BIS...ABR...OAX AND MPX ALL DEPICTED A VERY DRY
ATMOSPHERE. 850MB TEMPS HAVE WARMED FAIRLY DRAMATICALLY SINCE LAST
NIGHT TOO...WITH MPX JUMPING FROM -1C AT 00Z TO 13C AT 12Z. PLENTY
OF SUNSHINE...BREEZY SOUTHWEST WINDS WITH GUSTS FROM 30 TO 45 MPH
AND THE DRY AIR HAS ALLOWED FOR TEMPERATURES TO CLIMB INTO THE 60S
OVER MUCH OF THE FORECAST AREA. EXCEPTION TO THIS IS OVER THE
SNOWPACK IN TAYLOR COUNTY WHERE READINGS ARE STILL IN THE MID 50S.
DEWPOINTS HAVE STRUGGLED TO FALL MUCH SO FAR EARLY THIS AFTERNOON...
THOUGH. THINKING THIS IS DUE TO MOISTURE STILL IN THE SOIL
EVAPOTRANSPIRATING. CONDITIONS ARE STILL CONDUCIVE FOR FIRES...
THOUGH...NOTED BY A FIRE THAT OCCURRED NEAR MANKATO MN SEEN ON MPX
RADAR.
TONIGHT AND SUNDAY...TROUGHING OVER THE NORTHEAST PACIFIC IS PROGGED
TO SLIDE INTO THE PACIFIC NORTHWEST...CAUSING THE UPPER LOW IN NEW
MEXICO TO LIFT UP INTO THE CENTRAL PLAINS. THE SPEED OF THIS UPPER
LOW EJECTION HAS REMAINED NEARLY CONSISTENT FOR THE PAST FEW
DAYS...THOUGH THE SPEED AT WHICH MOISTURE/PRECIPITATION AHEAD OF THE
UPPER LOW HAS SLOWED DOWN. IN FACT...THE 10.12Z ECMWF...GFS...NAM...
CANADIAN AND UKMET ARE ALL NOW DRY FOR SUNDAY. GIVEN THE CURRENT DRY
AIRMASS...THINK THE DRIER TREND IS THE WAY TO GO AND REMOVED ANY
PRECIPITATION CHANCES FOR SUNDAY. WE SHOULD SEE SOME MID/HIGH CLOUD
COVER ADVECT IN FROM THE SOUTH DURING THE DAY SUNDAY...THOUGH. A
WEAKER PRESSURE GRADIENT IS PROGGED TONIGHT THAN WHAT OCCURRED THIS
MORNING...BUT A 5 TO 15 MPH SOUTHWEST WIND LOOKS TO PERSIST. THE
WIND WILL HELP TO KEEP TEMPERATURES UP SOMEWHAT...THOUGH THE DRY
AIRMASS DOES LEND ITSELF FOR BETTER RADIATIONAL COOLING.
THEREFORE...HAVE KEPT THE PREVIOUS FORECAST LOWS ABOUT THE SAME.
HIGHS ON SUNDAY ARE TRICKY BECAUSE OF THE INCOMING CLOUDS. CERTAINLY
THE DRY AIR AND A SOUTH TO SOUTHWEST WIND ARE HELPFUL TO HAVE
ANOTHER WARM DAY...IN ADDITION TO 850MB TEMPS HOLDING BETWEEN 8-10C.
DECIDED TO LEAN TOWARDS A BLEND OF THE MET/ECMWF/REGIONAL CANADIAN
GUIDANCE GIVEN GOOD PERFORMANCE IN THESE ABOVE NORMAL SCENARIOS.
SUNDAY NIGHT AND MONDAY...THE UPPER LOW IS FORECAST TO CONTINUE
EJECTING NORTHEASTWARD...CROSSING THE FORECAST AREA MONDAY MORNING.
BY 00Z TUESDAY...THE UPPER LOW SHOULD BE LOCATED OVER EASTERN LAKE
SUPERIOR. IMPRESSIVE CHANGE IN 500MB HEIGHTS FOR THE FORECAST AREA.
FROM 00-12Z MONDAY...THESE HEIGHTS FALL AROUND 150 METERS. SO
DEFINITELY GOOD FORCING IN THIS TIME PERIOD FOR PRECIPITATION. ON
THE FLIP SIDE...BETWEEN 12Z MONDAY-00Z TUESDAY...THE HEIGHTS RISE
40-100 METERS...INDICATING DECENT SUBSIDENCE. WHEN LOOKING AT MODEL
QPF OUTPUT THE SAME SIGNAL SHOWS UP...WHERE SHOWERS SPREAD SOUTH TO
NORTH SUNDAY NIGHT...THEN END SOUTHWEST TO NORTHEAST MONDAY. VERY
GOOD AGREEMENT EXISTS AMONGST THE MODELS FOR PRECIPITATION...SO HAVE
RAISED PRECIPITATION CHANCES UP TO 100 WITH A LITTLE EXTRA TIMING
INFORMATION INCLUDED. AS FAR AS QPF AMOUNTS GO...PRECIPITABLE WATER
VALUES CLIMB TO 250-300 PERCENT OF NORMAL...THOUGH MUCH OF THE LOW
LEVEL MOISTURE TRANSPORT ENDS UP SHUNTED OFF TO THE EAST. VERY
LITTLE IF ANY CAPE IS PROGGED DUE TO MOIST ADIABATIC LAPSE RATES. NO
HINTS AT ANY UPPER JET FORCING EITHER. THEREFORE...THINK QPF AMOUNTS
OVERALL WILL BE FAIRLY LIGHT...ON THE ORDER OF 0.25-0.5 INCHES. WITH
THE MOISTURE COMING UP...EXPECT LOWS TO STAY ON THE MILD SIDE SUNDAY
NIGHT. ON THE OTHER HAND...THE CLOUDS AND PRECIPITATION WILL TEND TO
KEEP THINGS COOLER ON MONDAY...RELATIVELY SPEAKING FOR MID MARCH
GIVEN THAT HIGHS ARE STILL GOING TO BE WELL ABOVE NORMAL.
MONDAY NIGHT AND TUESDAY...500MB HEIGHTS ARE PROGGED TO RISE
FURTHER...DUE TO THE UPPER LOW MOVING FARTHER AWAY...AND YET ANOTHER
UPPER TROUGH FORECAST TO DIG INTO THE PACIFIC NORTHWEST. AS
SUCH...WE GET A SURGE OF WARMER AIR AT 850MB TEMPS TO ADVECT INTO
THE FORECAST AREA...CLIMBING FROM 6-10C AT 12Z TUESDAY TO 10-12C AT
00Z WEDNESDAY. OTHER THAN A LITTLE LINGERING STRATUS EARLY MONDAY
NIGHT IN THE WAKE OF THE UPPER LOW...AS WELL AS A FEW MID CLOUDS TO
PASS THROUGH THE AREA ON TUESDAY...MUCH OF THIS TIME PERIOD LOOKS TO
BE CLEAR. IN FACT...SOUNDINGS ON TUESDAY LOOK PRETTY DRY WHICH
SHOULD ALLOW US TO WARM NICELY. SO AFTER A NIGHT IN THE MID 30S TO
LOW 40S MONDAY NIGHT...ANTICIPATING TEMPERATURES TO REBOUND BACK
WELL INTO THE 60S. IN FACT...SOME LOCATIONS COULD REACH 70...
ESPECIALLY IN FAR WESTERN SECTIONS.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
252 PM CST SAT MAR 10 2012
AS STATED IN PREVIOUS DISCUSSIONS AND STILL HOLDS TRUE...THE MAIN
STORY IS THE WELL ABOVE NORMAL WARMTH. PRETTY MUCH THE ENTIRE LONG
TERM PERIOD...ACCORDING TO ALL 10.00Z/12Z MODELS...FEATURES
SOUTHWEST FLOW FROM SAY NORTHERN CALIFORNIA INTO HUDSON BAY...
ALLOWING FOR RIDGING AND DOWNSLOPED PACIFIC AIR TO DOMINATE THE
EASTERN TWO THIRDS OF THE U.S.. TOWARDS THE WEEKEND...THE SOUTHWEST
FLOW AMPLIFIES OVER THE WESTERN U.S. AS DEEP TROUGHING FORMS ALONG
THE WEST COAST. IF ANYTHING...THIS COULD SEND EVEN WARMER AIR
TOWARDS THE FORECAST AREA. 850MB TEMPS THROUGHOUT THE LONG TERM
PERIOD ARE PROGGED AT 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. AS
SUCH...WE COULD BE DEALING WITH TEMPERATURES AT OR ABOVE RECORD
HIGHS EVERY DAY. IN GENERAL 850MB TEMPS HOLD BETWEEN 10-14C...WITH
THE WARMEST OF THESE ON WEDNESDAY. WITH WHAT LOOKS TO BE PLENTY OF
SUNSHINE THROUGHOUT...STAYED TOWARDS THE HIGH END OF ALL AVAILABLE
GUIDANCE AND FORECASTED HIGHS FROM THE UPPER 60S TO LOW 70S. THESE
ARE READINGS ARE MORE SIMILAR OF MID MAY THAN MID MARCH.
REGARDING PRECIPITATION CHANCES...THESE ARE RESTRICTED TO WEDNESDAY
NIGHT AND THEN FRIDAY THROUGH SATURDAY. FOR WEDNESDAY NIGHT...A
DYING COLD FRONT PROGGED TO MOVE THROUGH THE EASTERN PART OF THE
FORECAST AREA. NOT SURE IF THIS FRONT WILL CONVECT...BUT THE 10.12Z
ECMWF DOES SHOW A SHORTWAVE MOVING THROUGH THE FLOW ALOFT. THIS
SHORTWAVE COMBINED WITH A STREAM OF 850MB MOISTURE TRANSPORT AND
INSTABILITY COULD RESULT IN SOME CONVECTION. MAINTAINED JUST A 20
PERCENT CHANCE IN FAR SOUTHWEST WISCONSIN. FOR FRIDAY THROUGH
SATURDAY...A STREAM OF MOISTURE AND INSTABILITY COMING UP OUT OF THE
GULF OF MEXICO MAY COMBINE WITH SOME SHORTWAVES MOVING THROUGH THE
SOUTHWEST FLOW ALOFT TO INITIATE CONVECTION. HARD TO TIME AND EXACT
DETAILS VERY UNCERTAIN...THUS CHANCES ARE KEPT AT A MODEL CONSENSUS
20-40 VALUE.
IF THE CFS MODEL IS RIGHT...WHICH IT HAS BEEN DOING FAIRLY WELL THE
PAST FEW MONTHS...THE WELL ABOVE NORMAL WARMTH LOOKS TO PERSIST
THROUGH THE END OF THE MONTH AND INTO THE BEGINNING OF APRIL.
CERTAINLY IN THE LATEST 10.12Z ECMWF...THE WARM AIR AT LEAST STICKS
AROUND THROUGH NEXT MONDAY AND LIKELY WELL BEYOND.
&&
.AVIATION...THROUGH 06Z MONDAY
1101 PM CST SAT MAR 10 2012
VFR CONDITIONS EXPECTED THROUGH 03Z MONDAY. SOUTHERLY FLOW WILL
CONTINUE THROUGH THE TAF PERIOD WITH WIND SPEEDS GENERALLY 10 TO
15 KNOTS. SOME GUSTS TO 25 KNOTS IS POSSIBLE AT KRST BETWEEN 15Z-
22Z SUNDAY. CLOUDS WILL THICKEN SUNDAY AFTERNOON AHEAD OF AN
APPROACHING STORM SYSTEM LIFTING OUT OF THE DESERT SOUTHWEST.
MODELS CONSISTENT IN SHOWING LOW LEVEL SATURATION AND
PRECIPITATION BREAKING OUT BETWEEN 03Z-06Z AT BOTH TAF SITES. DID
LOWER CEILINGS INTO THE MVFR CATEGORY AT KRST AROUND 05Z AND COULD
POSSIBLE SEE MVFR CEILINGS PRIOR TO 06Z AT KLSE.
BEYOND THE TAF PERIOD EXPECT CEILINGS TO CONTINUE TO DROP...WITH
IFR CONDITIONS POSSIBLE...ESPECIALLY AT KRST AFTER 06Z.
&&
.CLIMATE...THROUGH SATURDAY
252 PM CST SAT MAR 10 2012
WE ARE APPROACHING RECORD HIGHS THIS AFTERNOON. WITH A FEW MORE
HOURS TO GO...POTENTIAL EXISTS FOR EITHER TYING OR BREAKING.
STATIONS THAT HAVE LONG PERIODS OF RECORD...OVER 115 YEARS...1894
RECORDS EXIST FOR DECORAH /66F/...LA CROSSE /67F/...MEDFORD
/53F/...AND WINONA /64F/. MEANWHILE THOSE WITH SHORTER DATA
BASES...THE TEMPERATURES WILL THREATEN RECORDS EITHER SET IN 1967
OR 1977.
LOOKING AHEAD...A STRING OF NEAR RECORDS OR RECORD HIGHS APPEAR
LIKELY FOR TUESDAY THROUGH SATURDAY...AND COULD EVEN GO BEYOND
THIS. IN ADDITION...WE COULD ALSO APPROACH OR BREAK RECORD HIGH
MINIMUMS. AN ABNORMALLY STRONG RIDGE AND WARM AIR IS PROGGED TO
REMAIN IN PLACE OVER THE EASTERN TWO THIRDS OF THE FORECAST AREA.
READINGS LOOK TO BE MORE SIMILAR OF MID MAY VERSUS MID MARCH. STAY
TUNED TO SEE HOW WARM WE ACTUALLY GET. RECORDS HAVE BEEN POSTED ON
OUR WEBSITE.
&&
.HYDROLOGY...THROUGH MONDAY
252 PM CST SAT MAR 10 2012
SIMILAR TO THE EARLIER HYDROLOGY DISCUSSION...SOME MINOR CONCERNS
ABOUT WHETHER ANY FLOODING WILL OCCUR ACROSS NORTH CENTRAL WISCONSIN
AS A RESULT OF A MELTING SNOW PACK AND RAIN SUNDAY NIGHT INTO
MONDAY. QPF AMOUNTS ARE STILL FORECAST BETWEEN 0.25-0.5 INCHES OVER
A LONG PERIOD WITH NO THUNDERSTORMS EXPECTED TO OCCUR. WITH GRADUAL
MELTING DUE TO THE WARMER TEMPERATURES...CURRENTLY EXPECT TO SEE
SOME RIVER RISES ALONG THE BLACK AND MAYBE TREMPEALEAU RIVERS...BUT
PROBABLY NOT UP TO FLOOD STAGE AT THIS POINT.
&&
.FIRE WEATHER...THROUGH SUNDAY
550 PM CST SAT MAR 10 2012
WILL ALLOW RED FLAG WARNING TO EXPIRE AT 6 PM.
LOOKING AHEAD TO SUNDAY...MORE MOISTURE STREAMING FROM THE SOUTH AND
INCREASING CLOUDS IN THE AFTERNOON SHOULD KEEP THE RELATIVE
HUMIDITIES FROM DROPPING BELOW 30 PERCENT. LOWEST HUMIDITIES ARE
PLANNED OVER SOUTHWEST WISCONSIN...WHICH IN THIS AREA THE FUELS ARE
A LITTLE MORE MOIST. WINDS ARE ALSO EXPECTED TO BE QUITE A BIT
LIGHTER THAN THOSE SEEN TODAY. THEREFORE...CONDITIONS FOR FIRES WILL
NOT BE AS GOOD AS THEY WERE TODAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
550 PM CST SAT MAR 10 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RABERDING
CLIMATE...BOYNE/AJ
HYDROLOGY...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1058 PM MST SAT MAR 10 2012
.UPDATE...
DEW POINT DEPRESSIONS ARE DOWN TO 5 DEGREES HERE AT KCYS AND 7 OUT
AT KSNY. HRRR IS BEGINNING TO CATCH ON TO THE POSSIBILITY OF FOG
DEVELOPMENT IN EXTREME SOUTHEAST WYOMING AND THE SOUTHERN HALF OF
THE NEBRASKA PANHANDLE THROUGH THE REST OF THE OVERNIGHT HOURS.
THE ONE CONCERN IS THAT MID/UPPER-LEVEL CLOUDS WILL BE THICKENING
AT THE SAME TIME WHICH MAY LIMIT THE SPATIAL EXTENT OF ANY FOG.
CONFIDENCE IS HIGH ENOUGH TO ADD AT LEAST PATCHY MENTION TO THE
FORECAST IN THESE AREAS.
&&
.AVIATION...06Z TAF ISSUANCE...
MOISTURE CONTINUES TO STREAM NORTH ALONG THE FRONT RANGE...SO AM
GROWING MORE CONCERNED FOR FOG DEVELOPMENT AT KCYS...KBFF...KSNY
AND KAIA THROUGH SUNRISE. ONE FLY IN THE OINTMENT IS MID/UPPER-
LEVEL CLOUDS THAT WILL BE STREAM NORTH INTO THE AREA AS
WELL...WHICH MAY LIMIT SOME OF THE LOWER FOG DEVELOPMENT.
CONFIDENCE IS HIGH ENOUGH TO ADD FOG MENTION TO THE AFOREMENTIONED
TAF SITES. ELSEWHERE...THE AIR MASS WILL REMAIN JUST TOO DRY FOR
ANY FOG DEVELOPMENT...SO KEPT THEM VFR THROUGH THE PERIOD. ANY FOG
THAT IS ABLE TO DEVELOP WILL LIFT BY THE MID-MORNING HOURS GIVING
WAY TO BREEZY VFR CONDITIONS ON SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 522 PM MST SAT MAR 10 2012/
UPDATE...
COOLING TEMPERATURES...CLIMBING RELATIVE HUMIDITIES AND CALMING
WINDS THIS EVENING HAS BROUGHT AN END TO CRITICAL FIRE WEATHER
CONDITIONS ACROSS THE WESTERN NEBRASKA PANHANDLE. THEREFORE...HAVE
ALLOWED THE RED FLAG WARNING TO EXPIRE ON TIME AT 5 PM.
AVIATION...00Z TAF ISSUANCE. CLEAR SKIES ACROSS THE FORECAST AREA
TONIGHT. WINDS RELATIVELY LIGHT ACROSS MOST LOCATIONS WITH SOME
GUSTS AROUND 20 KNOTS EARLY THIS EVENING.
PREV DISCUSSION... /ISSUED 304 PM MST SAT MAR 10 2012/
SHORT TERM...TONIGHT THROUGH TUESDAY
FORECAST CHALLENGES DEAL WITH TEMPERATURES...WINDS AND FIRE
WEATHER CONDITIONS THROUGH TUESDAY.
CURRENTLY...LEE SIDE TROUGH SEEN IN SURFACE ANALYSIS ACROSS EXTREME
EASTERN WYOMING THIS AFTERNOON IS MAKING A TRICKY SITUATION FOR
WINDS AND HUMIDITIES IN THE PANHANDLE. LOW LEVEL MOISTURE IS
ADVECTING NORTH FROM SOUTHERN COLORADO. HAVE 30 DEGREE DEW POINTS
IN THE SOUTHERN PANHANDLE AT SIDNEY WHILE JUST A COUNTY AWAY IN
KIMBALL...DEW POINTS ARE CURRENTLY 5. CURRENT RED FLAG WARNING IS
VERIFYING IN SOME LOCATIONS IN THE PANHANDLE...NAMELY
KIMBALL...BANNER AND BOX BUTTE COUNTIES...WITH THE REMAINDER OF
THE PANHANDLE PRETTY CLOSE. SO WILL KEEP THE RFW GOING THROUGH ITS
EXPIRATION TIME OF 5 PM. FURTHER SOUTH ACROSS NEW MEXICO...A
CUTOFF UPPER LOW CONTINUES TO SPIN...MOVING EVER SO SLOWLY
EASTWARD. THIS SYSTEM WILL GIVE US A REPRIEVE ON THE DRY
CONDITIONS POSSIBLY SUNDAY.
BY SUNDAY AFTERNOON...UPPER LOW IS FORECAST TO BE SITUATED ACROSS
THE WESTERN KANSAS/NEBRASKA BORDER JUST SOUTHWEST OF LEXINGTON
NEBRASKA. WINDS LOOK TO BE FAIRLY LIGHT ON THE NORTHWEST SIDE OF
THE LOW. MODELS HINT AT SOME VERY LIGHT QPF OVER THE SOUTHERN
PANHANDLE NEAR SIDNEY TONIGHT INTO SUNDAY AND CONTINUED THE
INHERITED SLIGHT CHANCE POPS FOR CHEYENNE COUNTY.
WINDS BEGIN TO INCREASE SUNDAY NIGHT INTO MONDAY AS A SHORTWAVE
TROUGH TRACKS FROM SOUTHERN IDAHO INTO MONTANA. 700MB WINDS
RESPOND BY INCREASING TO 50KT BY 12Z MONDAY...CONTINUING THROUGH
TUESDAY. AT THIS TIME...HAVE OUR WIND PRONE AREAS APPROACHING HIGH
WIND WARNING CRITERIA. WILL NEED TO WATCH FOR POSSIBLE HEADLINES
FOR MONDAY NIGHT INTO TUESDAY. VERY DRY CONDITIONS FORECAST EAST
OF THE LARAMIE RANGE WITH STRONG DOWNSLOPING WINDS. CONFIDENCE
GROWING THAT FIRE WEATHER HEADLINES WILL BE NEEDED FOR OUR FIRE
WEATHER ZONES REPORTING CURED FUELS FOR BOTH MONDAY AND TUESDAY
AFTERNOON.
LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...LONG RANGE MODELS
CONTINUE TO SHOW A BROAD UPPER LEVEL RIDGE DOMINATING THE WEATHER
PATTERN ACROSS THE CENTRAL UNITED STATES INTO FRIDAY AS A STRONG
UPPER LEVEL TROUGH REMAINS NEAR THE PACIFIC COASTLINE. THIS WILL
RESULT IN WEST TO SOUTHWEST FLOW ALOFT AND A CONTINUATION OF DRY
WEATHER ALONG WITH WARMER THAN NORMAL TEMPERATURES. HIGH
TEMPERATURES WILL BE MAINLY IN THE UPPER 60S TO MIDDLE 70S EAST OF
THE LARAMIE RANGE THROUGH NEXT WEEK WITH SOME RECORD HIGHS
POSSIBLE ON WEDNESDAY AND THURSDAY. WEST OF THE LARAMIE RANGE WILL
BE SLIGHTLY COOLER OVER THE HIGHER ELEVATIONS...BUT HIGHS WILL
STILL BE AROUND 60 DEGREES. A WEAK COOL FRONT WILL BRUSH THE
FORECAST AREA TUESDAY NIGHT AND WEDNESDAY...RESULTING IN WINDY
CONDITIONS ACROSS MOST OF SOUTHEAST WYOMING AS 700MB WINDS
INCREASE TO 50 KNOTS.
BY FRIDAY AND SATURDAY...MODELS SHOW SHORT WAVE ENERGY FROM THE
MAIN PACIFIC TROUGH EJECTING EAST AND NORTHEAST. THE TIMING OF THE
COOLER AIR AND POSSIBLE RAIN/SNOW IS UNCERTAIN...BUT EXPECT A
DRAMATIC CHANGE TO THE WEATHER PATTERN BY THE THIRD WEEK OF MARCH.
CONTINUED TO LOWER TEMPERATURES AND INCREASED POP ESPECIALLY WEST
OF THE LARAMIE RANGE THROUGH SATURDAY.
&&
.FIRE WEATHER...
WINDS WILL CONTINUE TO DECREASE THIS EVENING WITH FAIR TO
EXCELLENT OVERNIGHT HUMIDITY RECOVERIES. LOOK FOR A BRIEF REPRIEVE
IN THE WINDS SUNDAY BEFORE THEY BEGIN TO INCREASE AGAIN MONDAY
THROUGH TUESDAY. SIGNIFICANT FIRE WEATHER CONDITIONS WITH HIGH
WINDS AND LOW HUMIDITIES ARE POSSIBLE BOTH MONDAY AND TUESDAY
AFTERNOON FOR THE PANHANDLE AND EAST OF THE LARAMIE RANGE IN
SOUTHEAST WYOMING.
&&
.HYDROLOGY...WITH UNSEASONABLY WARM TEMPERATURES FORECAST FOR
THE NEXT SEVERAL DAYS...THE POTENTIAL FOR ICE JAM BREAKING AND
FLOODING WILL EXIST ALONG RIVERS AND STEAMS WEST OF THE LARAMIE
RANGE. THIS INCLUDES THE MEDICINE BOW...ENCAMPMENT...LITTLE SNAKE
AND UPPER NORTH PLATTE RIVERS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE/AVIATION...HAHN
SHORT TERM/FIRE WEATHER...CLAYCOMB
LONG TERM...TJT
AREA FORECAST DISCUSSION
NWS ALBANY NY
148 AM EDT TUE MAR 13 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION OVERNIGHT...AND THEN PASS
THROUGH EASTERN NEW YORK AND WESTERN NEW ENGLAND TOMORROW AFTERNOON.
THEN A BRIEF HIGH PRESSURE RIDGE WILL BE FOLLOWED BY ANOTHER SYSTEM
AT THE END OF THE WORK WEEK. HIGH PRESSURE WILL BUILD AND DROP IN
FROM SOUTHERN QUEBEC NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 130 AM...A BATCH OF SHOWERS MOVED THROUGH THE REGION WITH VERY
LITTLE QPF. AS OF NOW...THE RADAR INDICATED ONLY ISOLATED COVERAGE
AT THE MOMENT. FOLLOWED THE HRRR WHICH INDICATED A SLIGHT INCREASE
IN COVERAGE TO OUR SOUTH IN THE NEXT FEW HOURS. RADARS DO INDICATE A
BIT MORE ACTIVITY UPSTREAM THE HUDSON VALLEY...ACROSS THE POCONOS OF
PA...BUT AGAIN VERY LIGHT.
PHENOMENALLY MILD TEMPERATURES CONTINUE WITH THE CLOUDS OVER AND A
BIT OF A SOUTHERLY BREEZE. MOST PLACES HAVE TEMPERATURES IN THE
50S...WITH USUAL SPOTS IN MID TO UPPER 40S. SEE NO WAY TEMPERATURES
WILL FALL ALL THAT MUCH MORE OVERNIGHT AS DEWPOINTS LOOK TO INCREASE
SOME AS A VERY WEAK WARM FRONT MOVES TOWARD US. RAISED EVERYONE
ABOUT 3 DEGREES. THESE OVERNIGHT LOWS RANGING FROM THE LOWER 50S TO
LOWER 40S ARE MORE REPRESENTATIVE OF MID MAY THAN MID MARCH.
THE AXIS OF DEEPEST MOISTURE SEEN ON WATER VAPOR SATELLITE IMAGERY
HAS NOW TRACKED TO OUR EAST.
VERY LITTLE IF ANY RAIN IN THE DRY SLOT ACROSS WESTERN NEW YORK.
HOWEVER...A SOLID LINE OF SHOWERS AND SOME THUNDERSTORMS STILL
EVIDENT ACROSS EXTREME SOUTHEAST MICHIGAN ABOUT TO MOVE INTO NEW
YORK STATE. THIS LINE IS AHEAD OF A COLD FRONT THIS LOOKS TO CROSS
OUR REGION LATER TODAY. MORE ABOUT THAT IN OUR SHORT TERM.
FOR THE REST OF THE OVERNIGHT...NOTHING MORE THAN A LIGHT SHOWER OR
TWO...MAINLY SOUTH AND NORTH OF ALBANY. OTHERWISE ENJOY MILD
CONDITIONS WITH LOWS ONLY DOWN TO THE LOWER 50S CAPITAL
DISTRICT...45-50 MOST OTHER PLACES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 130 AM...DECIDED TO GO AHEAD AND TWEAK POPS LATER TUESDAY. IT
IS NOW CLEARLY EVIDENT THAT WHATEVER LINE ASSOCIATED WITH THE COLD
FRONT WILL GO THOUGH A LITTLE FASTER THAN EARLIER THOUGHT. HAVE SPED
IT UP A BIT...PROBABLY NOT ENOUGH BUT AT LEAST THE RIGHT TREND. THIS
LINE LOOKS TO MOVE ACROSS OUR REGION STARTING MID MORNING IN
NORTHWESTERN ZONES...SWEEPING OUR SOUTHEASTERN ZONES BY LATE
AFTERNOON. BEST FORCING REMAINS NORTH BUT BEST INSTABILITY SOUTH.
DECIDED TO MENTION SLIGHT CHANCE OF THUNDER EVERYWHERE BUT WILL
REVISIT CONVECTION ISSUES LATER ON.
NO CHANGE TO TEMPERATURES FOR TUESDAY AND BEYOND FOR NOW. IN
FACT...NO CHANGE TO LATER FORECASTS EXCEPT TO MAKE TUESDAY NIGHT
MAINLY DRY NOW.
WENT WITH ADJMET FOR TEMPS.
NEAR RECORD TEMPERATURES ARE POSSIBLE ONCE AGAIN ON TUESDAY...
THOUGH LESS PROBABLE...WITH HIGHS MAINLY FROM THE 60S TO LOWER
70S. WARMER AIR WILL HAVE A TOUGHER TIME GETTING UP THROUGH THE
OBSTRUCTING HIGHER TERRAIN...AND THERE...HIGHS WILL BE IN MAINLY
THE 50S. LOWS TUESDAY NIGHT WILL BE IN MAINLY THE 30S AND 40S...
AND WEDNESDAY WILL BE NOTICEABLY COOLER BEHIND THE FRONT...WITH
HIGHS FROM AROUND 40 DEGREES IN THE ADIRONDACK HIGH PEAKS...TO THE
MID 60S IN THE LOWER MID HUDSON VALLEY.
WEDNESDAY NIGHT LOOKS TO BE THE DRY PART OF THE EXTENDED AS
MARITIME RIDGE CRESTS DOWN THE NORTHEAST COAST. LOWS WEDNESDAY
NIGHT WILL BE MOSTLY IN THE UPPER 20S AND THE 30S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
HE LONG TERM PERIOD WILL START WITH A SFC HIGH PRESSURE RIDGE
DRAPING SOUTHWEST OVER THE ST LAWRENCE RIVER VALLEY THROUGH LONG
ISLAND WILL PRODUCE DRY WARM WEATHER ON THURSDAY. SFC LOW PRESSURE
OVER THE CENTRAL GREAT LAKES REGION ON THURSDAY WILL MOVE EASTWARD
FRIDAY...TOWARD WESTERN NY. THIS SYSTEM WILL BRING A WARM FRONT
FOLLOWED BY A COLD FRONT THROUGH THE NORTHEAST FRIDAY AND FRIDAY
NIGHT. MODEL GUIDANCE DIFFERING ON ASSOCIATED UPPER LEVEL FEATURE
TO THIS SYSTEM. GFS SHOWING THE UPPER LEVEL TROUGH TRACKING FURTHER
NORTH...WHILE THE ECMWF BREAKS A PIECE OF ENERGY FROM THE MAIN
TROUGH. THE MAIN TROUGH DIGS DEEPER SOUTH ON THE ECMWF...PRODUCING A
LONGER PERIOD OF RAIN SHOWERS. WITH LACK OF CAPE AND JET
DYNAMICS...HAVE NOT INCLUDED ANY EMBEDDED CONVECTIVE ACTIVITY AT
THIS TIME.
SFC HIGH PRESSURE WILL BUILD INTO THE NORTHEAST FROM THE JAMES BAY
AREA LATE SATURDAY...BRINGING AN END TO CHC OF PRECIP THROUGH MONDAY.
ABOVE NORMAL TEMPS WILL TREND EVEN WARMER...ESPECIALLY FOR THE
WEEKEND INTO THE EARLY WORK WEEK. MAX TEMPS RUNNING ABOUT 10 DEGREES
ABOVE NORMAL AT THE END OF THE WORK WEEK...WILL HAVE REINFORCED WAA
FROM SOUTHERLY FLOW THURSDAY AND FRIDAY...WARMING 850HPA TEMPS TO
6C-8C. THE AFOREMENTIONED WEAK COLD FRONT WILL SHIFT WINDS OUT OF
THE NORTH...KEEPING TEMPS AROUND 10 DEGREES ABOVE NORMAL OVER THE
WEEKEND. WARMEST TEMPS EXPECTED ON MONDAY AS HIGH PRESSURE PROVIDES
SUNNY SKIES AND 850 HPA TEMPS INCREASED TO AROUND 10C. THIS WILL
RESULT IN SFC MAX TEMPS IN THE 60S-L70S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
WHILE MAINLY VFR CONDITIONS ARE EXPECTED...THE CHANCE FOR MVFR
THRESHOLDS BEING SATISFIED ARE AROUND 50 PERCENT.
LATEST RADAR IMAGERY REVEALS DISORGANIZED AREA OF SHOWERS MIGRATING
ACROSS THE REGION THIS EARLY TUESDAY MORNING. WITHIN THESE
SHOWERS...CIGS DROP BACK BUT REMAIN WITHIN VFR CATEGORY. LATEST
RUC13/HRRR POINTS TOWARD A RENEW REGION OF SHOWERS EAST OF I81 AND
MIGRATING ACROSS THE REGION. WE WILL PLACE A TEMPO GROUP FOR MVFR
CIGS AT THIS TIME. THESE SHOWERS DEPART TO OUR EAST AROUND SUNRISE
WITH BORDERLINE VFR/MVFR CIGS REMAINING IN ITS WAKE. AS DAYTIME
HEATING COMMENCES...EXPECTATIONS ARE FOR THE CIGS TO IMPROVE TO
VFR.
THE CHANCE FOR CONVECTION APPEARS RATHER LOW AT THIS TIME AS THE
BEST DYNAMICS REMAIN TO OUR WEST AND NORTH. FOR THIS REASON...WE
WILL UTILIZE THE PROB30 GROUP NORTH OF KPOU FOR LATE MORNING INTO
THE MID AFTERNOON HOURS.
WINDS OVERNIGHT WILL BE SOUTH AT 5 KT OR LESS. A WEAK COLD FRONT
WILL TRACK THROUGH THE REGION BY MIDDAY TUESDAY. SO...WINDS WILL
BECOME WEST TO SOUTHWEST AT AROUND 10 KT.
OUTLOOK...
TUE NT-THU NT...VFR. NO SIG WX.
FRI-SAT...VFR/MVFR. CHC -SHRA.
&&
.FIRE WEATHER...
NO FIRE CONCERNS AS SHOWERS MOVE IN OVERNIGHT AND TEMPERATURES
DROP INTO THE 40S AT MOST LOCATIONS. LOW RHS TUESDAY WILL BE IN
MAINLY THE 45 TO 55 PERCENT RANGE. SCT SHOWERS WILL AFFECT MOST OF
THE REGION...ESPECIALLY IN THE AFTERNOON WITH THE POSSIBLE
ACCOMPANIMENT OF THUNDERSTORMS.
&&
.HYDROLOGY...
TOTAL QPFS SHOULD BE GENERALLY UNDER A QUARTER OF AN INCH...
ALTHOUGH LOCALLY UP TO A HALF INCH IS POSSIBLE. PERHAPS A DRY
PERIOD TUE MORNING BEFORE THE SHOWERS RETURN.
&&
.CLIMATE...
RECORD HIGHS
ALBANY NY: RECORDS DATE BACK TO 1874
MARCH 12: 67 DEGREES 1890
THE HIGH TODAY 69 DEGREES (AT 2:45 PM EDT)
MARCH 13: 70 DEGREES 1946
(PROJECT HIGH TUESDAY 67 DEGREES) NORMAL HIGH IS 43 DEGREES AND
LOW 24 DEGREES
GLENS FALLS NY: RECORDS DATE BACK TO 1949 MARCH 12: 66 DEGREES
1977 TIED AT 66 DEGREES AS OF 5 PM
MARCH 13: 71 DEGREES 1990 (PROJECTED HIGH TUESDAY 66 DEGREES)
NORMAL HIGH IS 41 DEGREES AND LOW 19 DEGREES
POUGHKEEPSIE NY: RECORDS DATE BACK TO 1949
MARCH 12: 65 DEGREES 1977
THE HIGH SO TODAY 72 DEGREES AS OF 5 PM
MARCH 13: 82 DEGREES 1990 (PROJECTED HIGH TUESDAY 72 DEGREES)
NORMAL HIGH IS 47 DEGREES AND LOW 24 DEGREES
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...ELH/NAS
NEAR TERM...HWJIV/KGM
SHORT TERM...ELH/HWJIV
LONG TERM...KGM
AVIATION...BGM
FIRE WEATHER...ELH
HYDROLOGY...IAA/HWJIV
CLIMATE...
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1147 PM CDT MON MAR 12 2012
.AVIATION...
PATCHY GROUND FOG EXPECTED THAT MAY REDUCE VISIBILITIES TO 1 TO 4
MILES THROUGH 13Z. THEN...VFR CONDITIONS TO CONTINUE THROUGH 06Z/14.
WITH CLEAR SKIES FROM WEAK HIGH PRESSURE. LIGHT WESTERLY WINDS TO
BECOME NEARLY CALM TUESDAY MORNING BEFORE SHIFTING TO THE SOUTH
IN THE AFTERNOON. ..NICHOLS..
&&
.PREV DISCUSSION... /ISSUED 310 PM CDT MON MAR 12 2012/
SYNOPSIS...
12Z UA ANALYSIS HAD A 700MB LOW OVER WESTERN MINNESOTA WITH
SEVERAL TROFS RUNNING FROM THE WESTERN GREAT LAKES BACK INTO THE
PLAINS. A MODERATELY STRONG LLJ RAN FROM THE OKLAHOMA PANHANDLE
INTO THE GREAT LAKES. SATELLITE TRENDS SHOWS A VORT MAX MOVING
FROM NORTHERN MISSOURI INTO NORTHERN ILLINOIS WHILE THE MAIN VORT
MAX MOVES INTO NORTHERN WISCONSIN. RADAR SHOWS SPRINKLES OVER THE
AREA WITH SOME LOW CONVECTION OVER NORTHEAST ILLINOIS.
18Z SFC ANALYSIS HAS A WEAK LOW NEAR KDLH WITH A WARM FRONT RUNNING
SOUTHEAST TO NEAR DETROIT. A COLD FRONT RAN FROM THE LOW SOUTH TO
KUIN. DEW POINTS WERE IN THE 50S AND 60S OVER THE GREAT LAKES AND
LOWER MISSISSIPPI VALLEY WITH 30S AND 40S OVER MUCH OF THE PLAINS.
SHORT TERM...TONIGHT AND TUESDAY...
REFER TO THE CLIMATE SECTION BELOW FOR RECORD HIGHS FOR MARCH 13TH
AND 14TH.
CURRENT OBSERVATIONS THROUGH 20Z COMBINED WITH RECENT RUC TRENDS
INDICATE THE WINDOW OF OPPORTUNITY FOR ANY NEW CONVECTION IS
CLOSING. RADAR INDICATES SPRINKLES WITH SOME VERY MINOR SHOWERS OVER
THE SOUTHEAST HALF OF THE CWFA BUT RUC TRENDS INDICATE THE
INSTABILITY NEEDED TO GET ANYTHING STRONGER GOING WILL END BY 2130Z.
THUS SPRINKLES WITH PERHAPS A FEW SHRA WILL CONTINUE THROUGH SUNSET
WITH POSSIBLY AN ISOLD TSRA IN THE FAR EASTERN/SOUTHEASTERN CWFA.
SATELLITE TRENDS INDICATE THE CLOUDS ARE TAKING ON A MORE CELLULAR
NATURE AND WILL SLOWLY DISSIPATE WITH SUNSET.
SO A CLEARING TREND WILL OCCUR TONIGHT AS THE STORM SYSTEM MOVES
INTO CANADA. HIGH PRESSURE BUILDING INTO THE CWFA LATE TONIGHT WILL
RESULT IN LIGHT WINDS WHICH SHOULD ALLOW TEMPERATURES TO BECOME
CHILLY BUT STILL ABOVE NORMAL.
THE HIGH WILL INITIALLY LIMIT MIXING ON TUESDAY UNTIL IT MOVES EAST
OF THE AREA. RETURN FLOW DEVELOPING BY MID DAY COMBINED WITH THE
STRONG MARCH SUN WILL ALLOW TEMPERATURES TO CLIMB WELL ABOVE NORMAL.
THE NORTHERN THIRD OR SO OF THE CWFA SHOULD REACH THE UPPER 60S WITH
70 TO 75 ELSEWHERE. ..08..
LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BOTH SFC AND UPPER RIDGE
AXIS WILL MIGRATE OFF TO THE EAST OF THE CWA INTO WED MORNING
ALLOWING RETURN FLOW TO INCREASE LATE TUE NIGHT FOR NON-DIURNAL
TEMP CURVES. LOWS WILL PROBABLY OCCUR FROM 03Z-07Z WED BEFORE STEADY
TO SLOW RISE TREND BEGINS. AS SFC FRONT TRIES TO SAG TOWARD THE CWA
FROM THE NORTHWEST...THE CWA WILL BECOME UNDER FULL INFLUENCE OF
WARM THRUST. ONLY THE WET BIASED 12Z GFS BREAKS OUT PRECIP ON WED
BEFORE 00Z THU AND WILL REMOVE ANY DAYTIME POPS. MORE INSOLATION AND
EXTENT OF CURRENTLY PROGGED THERMAL PROFILES SUGGEST HIGHS IN THE
MID TO UPPER 70S ON WED WITH THE SHOT AT A FEW 80S...ALL OF WHICH
WILL BE RECORD HIGH TERRITORY FOR ALL CLIMATE SITES FOR MARCH 14TH.
FLATTENING RIDGE-RIDING VORT WILL COMBINE WITH LLVL MOISTURE
CONVERGENCE ALONG THE INCOMING FRONT FOR A CHANCE AT SOME NOCTURNAL
SHOWERS AND THUNDERSTORMS WED NIGHT. IF A STORM COULD GET GOING IN
THE LOCAL AREA WED AFTERNOON AND EARLY EVENING AND BECOME SOMEWHAT
ORGANIZED...FCST SOUNDINGS SUGGEST A POTENTIAL FOR A SVR STORM WITH
LARGE HAIL AND DAMAGING WIND...BUT AGAIN A TRIGGER DOES NOT APPEAR
UNTIL LATER THAT NIGHT. ALSO THESE SVR PARAMETERS ARE BEING
ADVERTISED ON THE GFS AND ESPECIALLY THE NAM FCST SOUNDINGS WHICH MAY
AGAIN BE OVERDOING BOUNDARY LAYER MOISTURE.
THURSDAY AND FRIDAY...FLATTENING NON-SENSIBLE FLOW ACRS THE
MIDWEST...UNSEASONABLY MILD REGIME CONTINUES WITH LITTLE FOCUS FOR
ORGANIZED CONVECTION. WILL KEEP LOW POPS FOR WDLY SCTRD SHOWERS OR
THUNDERSTORMS POPPING UP IN THE AFTERNOON CAPES. HIGHS IN THE MID TO
UPPER 70S BOTH DAYS AS MAY ARRIVES EARLY.
SATURDAY THROUGH MONDAY...MOST 12Z RUN MEDIUM RANGE SOLUTIONS AND
LATEST ENSEMBLES SUGGEST PATTERN TO BECOME HIGH AMPLITUDE SINE WAVE
PATTERN ACRS THE CONUS...WITH THE MID MS RVR VALLEY STUCK IN THE
MIDDLE FOR THE REST OF THE EXTENDED. WARM MOIST CONVEYOR UP OFF THE
WESTERN GULF TO CONTINUE TO FLOW UP INTO THE REGION TO FUEL POSSIBLE
SHOWER AND THUNDERSTORM ACTIVITY...BUT AGAIN NO REAL SYNOPTICS SCALE
FEATURES TO SUGGEST MORE ORGANIZATION TO THE CONVECTION EVIDENT AT
THIS TIME THROUGH AT LEAST MON NIGHT...POSSIBLY NOT UNTIL MID NEXT
WEEK AS HIGH AMPLITUDE PATTERN SLOW TO MOVE. THUS WILL KEEP LOW
DIURNAL CHANCES FOR WDLY SCTRD UNORGANIZED CONVECTION IN MAINLY
DAYTIME HEATING WHICH MAY LEAD TO HIGHS IN THE MID TO UPPER 70S
EVERY DAY. ..12..
CLIMATE... RECORD HIGHS FOR MARCH 13TH...
BURLINGTON........77 IN 2007 AND OTHER YEARS
CEDAR RAPIDS......74 IN 2007
DUBUQUE...........71 IN 2007
MOLINE............77 IN 2007
RECORD HIGHS FOR MARCH 14TH...
BURLINGTON........76 IN 1995
CEDAR RAPIDS......75 IN 1995
DUBUQUE...........72 IN 1995
MOLINE............77 IN 1995
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 AM EDT TUE MAR 13 2012
.SYNOPSIS...
ISSUED AT 413 PM EDT MON MAR 12 2012
UNSEASONABLY WARM WEATHER WILL DOMINATE THIS WEEK AS ABOVE NORMAL
500MB HEIGHTS RISE SLOWLY OVERALL. INTO THE UPCOMING WEEKEND...500MB
HEIGHT ANOMALIES OVER THE UPPER LAKES WILL INCREASE FROM 2 TO 2.5
STANDARD DEVIATIONS ABOVE THE LONG TERM AVG FOR MID MARCH. 850MB
TEMPS WILL ALSO BE RUNNING 2-2.5 STANDARD DEVIATIONS ABOVE THE LONG
TERM AVG. OVERALL...IT WILL PROBABLY FEEL MORE LIKE MID MAY THAN MID
MARCH. AT LEAST HERE AT THE OFFICE...SEVERAL HIGH TEMP RECORDS WILL
PROBABLY BE CHALLENGED OVER THE NEXT 7 DAYS. RAIN CHANCES LOOK
LIMITED WITH TROF SETTING UP WELL TO THE W OVER THE WRN CONUS AND A
STRONG RIDGE BUILDING OVER THE ERN CONUS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 413 PM EDT MON MAR 12 2012
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL
LOW SPINNING NE THRU WI. MAIN ARC OF STEADIER PCPN ASSOCIATED WITH
SYSTEM HAS LIFTED N AND E THRU UPPER MI TODAY. SCT PCPN IS OCCURRING
CLOSER TO THE CENTER OF THE MID LEVEL LOW WITH COVERAGE GENERALLY
INCREASING. UNDER APPROACHING COLD POCKET ALOFT ASSOCIATED WITH THE
LOW...A FEW LIGHTNING STRIKES HAVE FINALLY BEEN NOTED OVER CNTRL WI.
AFTER MORNING RAINFALL SATURATED THE LOW-LEVELS AND WITH PCPN LESS
WIDESPREAD THIS AFTN...FOG IS FAIRLY WIDESPREAD WITH SOME AREAS OF
DENSE FOG ALONG LAKE MICHIGAN AND WHERE WINDS ARE UPSLOPING.
WITH MID LEVEL LOW MOVING ACROSS THE AREA THIS EVENING...EXPECT
SCT/NMRS SHRA THIS EVENING. MAINTAINED SLIGHT CHC THUNDER OVER THE
SCNTRL THRU LATE AFTN SINCE SHRA ACTIVITY AROUND LOW APPEARS TO BE
INCREASING IN INTENSITY AND A FEW LIGHTNING STRIKES HAVE RECENTLY
OCCURRED IN CNTRL WI. SHORTWAVE CURRENTLY OVER THE DAKOTAS MAY WORK
TO MAINTAIN BETTER COVERAGE OF SHRA INTO THE LATE EVENING HRS OVER
THE NW PORTION OF THE FCST AREA AS IT TRACKS TO LAKE SUPERIOR.
OTHERWISE...PCPN LOOKS TO END RATHER QUICKLY OVERNIGHT FROM W TO E
AS STRONG DRYING SURGES INTO THE AREA UNDERNEATH UPPER JET.
-SHRA MAY LINGER INTO THE MORNING HRS OVER THE FAR NE FCST AREA.
OTHERWISE...THE STRONG DRYING WILL SET THE STAGE FOR A SUNNY DAY
TUE. DEEP DRY AIRMASS WILL SUPPORT DEEP MIXING...PERHAPS TO
800-750MB. PER FCST SOUNDINGS...THAT WILL YIELD MAX TEMPS AROUND 60F
OVER THE SCNTRL WHERE DOWNSLOPING WRLY WINDS WILL AID WARMING. 50S
SHOULD BE THE RULE ELSEWHERE...WITH LWR 40S ON THE W SIDE OF THE
KEWEENAW AND ALONG LAKE SUPERIOR E OF MUNISING DUE TO WINDS OFF THE
COLD WATERS. GIVEN THE VERY DRY AIRMASS ALOFT THAT CAN BE TAPPED...
LEANED TOWARD DWPTS THAT CAN BE ACHIEVED BY MIXING TUE AFTN.
ALTHOUGH POTENTIAL IS THERE FOR DWPTS TO CRASH TOWARD 0F OVER THE
FAR W AND CNTRL FCST AREA...OPTED TO JUST TREND FCST IN THAT
DIRECTION BY LOWERING GOING FCST SEVERAL DEGREES TO AROUND 10F AS A
START. THIS WILL PUT AFTN RH VALUES DOWN AROUND 15PCT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 413 PM EDT MON MAR 12 2012
THE PERIOD STARTS 00Z WEDNESDAY WITH A LOW PRESSURE SYSTEM ENE OF
THE CWA AND A 500MB RIDGE OF HIGH PRESSURE CENTERED JUST W OF THE
CWA. AT THE SAME TIME...AN UPPER SHORTWAVE TROUGH WILL BE OVER THE
NWRN CONUS/WRN CANADA...WITH A SFC LOW OVER SASK AND SFC TROUGHING
LEEWARD OF THE ROCKIES STRETCHING INTO CO.
THE UPPER RIDGE WILL BE OVER THE CENTER OF THE CWA BY 12Z WED. THE
NW CONUS SHORTWAVE WILL BE NEAR THE NRN SASK/MANITOBA
BORDER...PUSHING THE SFC TROUGH FARTHER E INTO FAR WRN MN. THE
EASTWARD MOVING TROUGH COMBINED WITH A SFC RIDGE JUST E OF THE CWA
WILL RESULT IN INCREASING SW WAA TUE NIGHT INTO WED. 850MB TEMPS
WILL INCREASE FROM 0-5C BY 00Z WED TO 10-13C BY 18Z WED. THIS
RESULTS IN VERY WARM TEMPS FOR WED...WITH HIGHS IN THE MID TO UPPER
60S EXPECTED OVER PORTIONS OF CENTRAL AND WRN UPPER MI...ESPECIALLY
IN DOWNSLOPING AREAS. OVER ERN UPPER MI...HIGHS WILL BE LOWER IN THE
LOW TO MID 50S WITH THE SSW FLOW OFF LAKE MI. THROUGH 00Z THU THINGS
SHOULD STAY DRY AS THE SFC TROUGH MOVES INTO THE FAR WRN CWA. THE
NAM SHOWS SOME CONVECTION POPPING UP BETWEEN 18Z WED AND 00Z THU
OVER THE FAR ERN CWA...BUT THE NAM IS ALSO THE FASTEST WITH MOVING
THE COLD FRONT THROUGH. WITH THE CONSENSUS IDEA...THE COLD FRONT
WILL BE MOVING OUT OF THE SERN CWA BY 00Z FRI. CONSENSUS MODELS ALSO
SHOW CONVECTION OVER CENTRAL AND ERN UPPER MI...BUT MAINLY NEAR LAKE
MI AND OVER FAR ERN UPPER MI AFTER 00Z THU. THE HEAVIER CONVECTION
SHOULD STAY S/SE OF THE CWA AS MODELS SHOW TOO MUCH CAPPING THIS FAR
N...SO SLIGHT CHANCE OF THUNDER WAS RETAINED FROM PREVIOUS FORECAST.
THURSDAY...WITH THE COLD FRONT STALLING JUST SE OF THE CWA...RAIN
WILL REMAIN POSSIBLE NEAR LAKE MI AND E...BUT ONLY CHANCE TO SLIGHT
CHANCE POPS SEEM WARRANTED AT THIS TIME. THURSDAY LOOKS TO BE COOLER
BEHIND THE COLD FRONT WITH 850MB TEMPS AROUND 7C...SO HIGHS WILL BE
IN THE 40S NEAR LAKE SUPERIOR AND NEAR 60 NEAR THE WI BORDER.
FOR THE EXTENDED...MODELS SHOW ANOTHER UPPER DISTURBANCE MOVING N OF
THE CWA THU NIGHT...WITH AN UPPER RIDGE MOVING OVER THE CWA ON FRI.
AFTER FRI...CONFIDENCE IS DECREASED SOME AS MODELS SHOW DIFFERING
SOLUTIONS WITH THE PASSAGE OF A SERIES OF SHORTWAVES THROUGH MONDAY.
HOWEVER...WARM CONDITIONS ARE A CERTAINTY INTO EARLY NEXT WEEK GIVEN
STEADY S/SW FLOW WITH SFC HIGH PRESSURE E AND LOW PRESSURE W. USED
CONSENSUS OF MODELS THROUGH THE EXTENDED WITH SLIGHT CHANCE TO LOW
CHANCE POPS AS MODELS SHOW SOME PRECIP/CONVECTION IN THE WAA REGIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 127 AM EDT TUE MAR 13 2012
MID LVL TROF WILL LIFT NE OF THE REGION OVERNIGHT ALLOWING FOR MUCH
DRIER AIR TO MOVE IN FROM THE SW SCOURING OUT STRATUS CLOUD DECK.
MVFR CLOUD DECK SHOULD DISSIPATE BY TAF VALID TIME AT KIWD AND BY 09Z
AT KSAW. AT KCMX...UPSLOPE AIDED IFR CIGS AT KCMX SHOULD ALSO LIFT BY
09Z WITH INFLUX OF DRIER AIR. KEPT LLWS AT KSAW AS WINDS REMAIN
DECOUPLED OVERNIGHT. WITH DEEP MIXING EXPECTED UNDER SUNNY
SKIES...EXPECT WRLY WIND GUSTS TO APPROACH 30 KTS AT KCMX DURING THE
DAY ON TUESDAY AND AOA 20 KTS AT BOTH KSAW AND KIWD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 413 PM EDT MON MAR 12 2012
UPPER LEVEL DISTURBANCE AND SURFACE TROF WILL MOVE ENE ACROSS LAKE
SUPERIOR TONIGHT. AHEAD OF THE TROF...SHOWERS AND INCREASINGLY MOIST
AIRMASS WILL SUPPORT SOME FOG...ESPECIALLY OVER WRN AND NRN PORTIONS
OF THE LAKE. FOG SHOULD THIN OUT AFTER TROF PASSES AND WINDS SHIFT
AROUND TO THE W AND INCREASE. WARM AIR ABOVE THE SURFACE WILL LIKELY
KEEP THE MARINE LAYER IN PLACE AND LIMIT THE STRONGER WINDS ALOFT
FROM REACHING THE SURFACE LATE TONIGHT AND TUE. AT THIS TIME...ONLY
EXPECT GUSTS REACHING 30KTS. AFTER TUE...WINDS WILL PROBABLY REMAIN
MOSTLY UNDER 20KTS WITH A RELATIVELY WEAK PRESSURE GRADIENT IN
PLACE. UNSEASONABLY WARM AIRMASS OVER THE UPPER GREAT LAKES WILL
ALSO RESULT IN PERSISTENT MARINE LAYER/STRONG STABILITY OVER THE
LAKE...HELPING TO KEEP WINDS LIGHTER.
&&
.HYDROLOGY...
ISSUED AT 413 PM EDT MON MAR 12 2012
NEAR RECORD TO RECORD SETTING TEMPS YESTERDAY HAS HELPED RIPEN THE
SNOW PACK. RAIN MOVING THROUGH TODAY WILL EXIT THE AREA TONIGHT. THE
BULK OF THE RAIN FELL DURING THE MORNING TO EARLY AFTERNOON HOURS
TODAY...WITH ACCUMULATIONS OF AROUND 0.25 TO 0.70IN. THE
RAIN...COMBINED WITH DEWPOINTS IN THE 40S...WILL HELP TO QUICKEN
SNOWMELT THIS EVENING. AS OF THIS AFTERNOON...LARGER RIVERS ARE
STARTING TO SHOW SOME INCREASED RESPONSE TO THE MELTING AND
PRECIPITATION.
THE RAIN AND SNOW MELT TODAY...COMBINED WITH ABOVE NORMAL
TEMPERATURES THROUGH NEXT WEEKEND WILL LEAD TO A INCREASE IN
RIVER AND STREAM LEVELS OVER THE NEXT SEVERAL DAYS. EXPECT SOME OF
THE RIVERS ACROSS THE AREA TO EXCEED THEIR BANKS BY THE END OF THIS
WEEK. PERSONS LIVING NEAR RIVERS AND STREAMS SHOULD
MONITOR THE LATEST RIVER CONDITIONS AND USE CAUTION IF WALKING
ALONG RIVER BANKS...ESPECIALLY THE CHOCOLAY RIVER...TRAP ROCK
RIVER...AND THE STURGEON RIVER IN WESTERN UPPER MICHIGAN.
ICE JAM WISE...NOT MUCH ICE HAS BEEN NOTED BY OBSERVERS ON THE
FASTER FLOWING RIVERS OVER NRN UPPER MI. BUT THE FORD RIVER...BOTH
AT HYDE AND THE MOUTH AT LK MI...STILL HAS GOOD ICE COVER THAT
LEADS TO SOME CONCERN FOR ICE JAM POTENTIAL WITH THE FASTER RUNOFF.
ALTHOUGH LIMITED SNOW WAS NOTED NEAR LK MI...THERE IS STILL 3-8IN
OF SNOW ...AND NOHRSC ESTIMATED AROUND 1.25IN OF LIQUID...TOWARDS
THE HEADWATERS THAT WILL BE MELTED OVER THE COMING DAYS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...ROLFSON
SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...VOSS
MARINE...ROLFSON
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
103 AM EDT TUE MAR 13 2012
.AVIATION...
//DISCUSSION...
SHOWERS WILL CONTINUE TO SETTLE SOUTHEAST OF THE TERMINALS...ENDING
AT YIP/DTW/DET RIGHT ABOUT THE START OF THE FORECAST PERIOD. VFR
CIGS WILL PERSIST A BIT LONGER...WITH ~10KFT AC DECK UNTIL 08Z-10Z.
THEREAFTER...STRATUS WILL WRAP AROUND THE DEPARTING UPPER LOW AND
BRING A SLIGHTLY LOWER DECK INTO MBS/FNT...WITH CIGS IN THE 4-5KFT
AREA LATE TONIGHT INTO EARLY WEDNESDAY. OTHERWISE...CLEARING SKIES
CAN BE EXPECTED DURING THE DAY WITH GUSTY WEST WINDS DURING THE BEST
MIXING FROM LATE MORNING INTO LATE AFTERNOON...WITH WIND GUSTS TO 25
KNOTS AT TIMES. HIGH PRESSURE WILL MAINTAIN CLEAR SKIES INTO THE END
OF THE FORECAST PERIOD...AND ALSO ALLOW WINDS TO DROP OFF QUICKLY
AFTER 22Z-00Z.
//DTW THRESHOLD THREATS...
* NONE
&&
.PREV DISCUSSION...ISSUED 351 PM EDT MON MAR 12 2012
SHORT TERM...THIS EVENING AND TONIGHT
STRONG UPPER LOW NOW LOCATED OVER NORTHERN WISCONSIN WILL CONTINUE
TO TRACK TO THE NE ACROSS LAKE SUPERIOR TONIGHT. THE SURFACE
REFLECTION IS RATHER WEAK AS IT REMAINS AN OPEN TROUGH TIED TO A
CLOSED CIRCULATION FURTHER NW OVER MANITOBA. MID LEVEL DRY SLOT IS
WORKING ITS WAY ACROSS SOUTHERN MI PUSHING THE DEEPER MOISTURE FROM
THIS MORNING OFF TO THE EAST. BREAKS IN THE CLOUD COVER HAS ALLOWED
SOME DIURNAL HEATING OVER FAR SW LOWER MI. TEMPS ARE PUSHING THE
UPPER 60S IN THOSE LOCATIONS. IN ADDITION...S/SW WINDS GUSTING UP TO
25 KNOTS HAS BROUGHT IN ABUNDANT SFC MOISTURE WITH DEWPOINTS IN THE
MID 50S ACROSS ALL OF SOUTHERN MI. THE EXCEPTION IS OVER THE EXTREME
EASTERN PORTIONS OF THE CWA WHERE A SE COMPONENT IS STILL HANGING
ON. THIS HELD THE SUB 1000FT CLOUDS FIRMLY UNTIL ABOUT THE LAST WHEN
THEY STARTED TO SCATTER OUT. THUNDERSTORM COMPLEX FROM EARLIER WEST
OF CHICAGO HAS TRACKED NORTH INTO WESTERN MI NORTH OF MUSKEGON. WITH
WIND SHEAR NEARLY UNIDIRECTIONAL FROM THE SW...COMPLEX IS STRUGGLING
TO MAKE ANY EASTWARD PROGRESS.
FOR TONIGHT...THREAT FOR SEVERE WEATHER LATE THIS EVENING REMAINS
CONDITIONAL ON AMOUNT OF SURFACE BASED INSTABILITY WE CAN ACHIEVE.
THERE LOOKS TO BE PLENTY OF WIDESPREAD LIFT SUPPORTING STORM
DEVELOPMENT WITH THE UPPER LEVEL COLD POOL IN PLACE AND THE ENTRANCE
REGION OF A JET STREAK OVER THE REGION. THERE ARE FAVORABLE WIND
PARAMETERS ASSOCIATED WITH THE FRONTAL PASSAGE. BULK SHEAR VALUES
AROUND 40-50 KNOTS...BOTH 0-3KM AND 0-1 KN HELICITY IN EXCESS OF 300
M2/S2. LOOKING AT CAPE VALUES...THOUGH NAM MUCAPE IS ADVERTISED AT
800J/KG...NEITHER THE NAM OR RUC FIND MUCH IN THE WAY OF SFC BASED
CAPE WITH VALUES UP TO 100-200 J/KG WITH HIGHEST AMOUNTS FOR THE
WESTERN PART OF THE CWA. HIRES MODELS SHOW SOME ISOLATED CELLS
TRYING TO GO UP IN ADVANCE OF THE COLD FRONT WITH THE BULK OF THE
SHOWERS/STORMS OCCURRING THE FRONT ITSELF MAINLY FROM
23Z-05Z...WORKING SOUTH FROM MBS TO DTW. LOOKS LIKE SMALL HAIL AND
WIND GUSTS TO 50MPH WILL BE THE MOST LIKELY RESULTS OF THESE
STORMS...ALTHOUGH IF WE CAN GET MORE SFC BASED INSTABILITY SEVERE
STORMS WILL NOT BE OUT OF THE QUESTION.
LONG TERM...
THE WARM PATTERN LOOKS TO STICKING AROUND FOR THE EXTENDED
PERIOD...WITH POTENTIAL PSEUDO OMEGA BLOCKING PATTERN SETTING UP
LATE IN THE WEEKEND/EARLY NEXT WEEK.
CONSOLIDATING UPPER WAVES TAKES PLACE OVER ONTARIO TOMORROW...WITH
SHORTWAVE TROUGH AXIS AND SLIGHT HEIGHT FALLS TAKING PLACE LATE IN
THE DAY. STILL...WITH FAVORABLE WESTERLY WINDS AND THE TEMP GRADIENT
ADVERTISED (925 MB TEMPS OF 8 C NORTH TO 11 C SOUTH)...LOOKING AT
UPPER 50S NORTH TO MID 60S SOUTH WITH PLENTY OF SUNSHINE.
SURFACE RIDGE AXIS ARRIVING TOMORROW EVENING SHOULD ALLOW FOR
FAVORABLE RADIATING CONDITIONS...BUT WE ALREADY HAVE MODEST LOW
LEVEL WARM ADVECTION RETURNING BY SUNRISE WEDNESDAY. GUIDANCE TEMPS
IN THE 30S APPEAR REASONABLE.
A DRY WARM FRONT EXPECTED TO PUSH NORTH OF SOUTHERN LOWER MICHIGAN
DURING WEDNESDAY AS UPPER LEVEL RIDGE BUILDS OVERHEAD...PUSHING
TEMPS TO 70 DEGREES OR BETTER BASED ON FORECASTED 925 MB TEMPS OF
+15 TO +16 C. THE EXCEPTION WILL BE ACROSS THUMB REGION WHERE FRONT
WILL PROBABLY NOT CLEAR BY DAYS END...WITH BACKED SOUTHEAST FLOW
COMING OFF COOL WATERS OF SOUTHERN LAKE HURON.
DEEP SOUTHWEST FLOW OVER THE CENTRAL CONUS THURSDAY/FRIDAY...WITH
POTENTIAL UPPER LEVEL PV FILAMENT ROLLING THROUGH ON THURSDAY...PER
12Z GFS...TO TRIGGER SHOWERS AND POSSIBLE THUNDERSTORMS...AS
RESPECTABLE SURGE IN MOISTURE TAKES PLACE. CLOUDS AND CONVECTIVE
ACTIVITY COULD BE ENOUGH TO KEEP TEMPS STUCK IN THE UPPER 60S
DESPITE THE VERY MILD START TO THE DAY. THE 12Z EUROPEAN OFFERS A
DIFFERENT SOLUTION AND SUGGESTS THE SHORTWAVE/TROUGH COMING OUT OF
THE NORTHERN PLAINS WILL BE STRONGER...MOVING THROUGH ON FRIDAY.
THIS WOULD TRANSLATE TO A WARM DAY ON THURSDAY (70S) AND BETTER
CHANCE OF SHOWERS ON FRIDAY. THE CANADIAN IS MORE IN LINE WITH THE
GFS...SO WILL NOT MAKE A BIG PUSH TO EXTENDED GRIDS MUCH.
MEDIUM RANGE MODELS STILL FORECASTING AMPLIFIED PATTERN FOR THE
WEEKEND INTO EARLY NEXT WEEK...WITH LONGWAVE TROUGH OUT WEST AND
UPPER LEVEL RIDGE BUILDING NEAR THE GREAT LAKES REGION. ALMOST
SUMMER LIKE RIDGE (582-586 DAM AT 500 MB)...AND TEMPS APPROACHING 80
DEGREES IS NOT OUT OF THE QUESTION AS WE GET TO TUESDAY AS 1000-500
MB THICKNESSES CLIMB TOWARD 564 DAM. LAKE BREEZES WOULD LIKELY BE
COMING INTO PLAY HOWEVER AND WILL NEED TO REMAIN MORE CONSERVATIVE
THAT FAR OUT...ESPECIALLY WITH THE EUROPEAN PROFILES A BIT COOLER.
MARINE...
OUTSIDE OF A FEW POSSIBLE THUNDERSTORMS THIS EVENING...MARINE
CONDITIONS ARE EXPECTED TO REMAIN QUIET. UNUSUALLY MILD AIR IN PLACE
FOR EARLY MARCH WILL LEAD TO STABLE STABLE LOW LEVEL PROFILES OVER
THE GREAT LAKES. THIS WILL MINIMIZE THE GUST POTENTIAL TO AROUND 20
KNOTS OVER THE NEXT SEVERAL DAYS. THOSE STRONGER WINDS LOOKED TO BE
CONFINED TO THE NORTH THIRD OF LAKE HURON TOMORROW...AS CHANNELING
OCCURS WITH WESTERLY FLOW. THE NEXT CHANCE OF THUNDERSTORMS RETURNS
ON THURSDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...DRK
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS RALEIGH NC
200 AM EDT TUE MAR 13 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO LINGER OFFSHORE...AND EXTEND OVER
MUCH OF THE REGION...FOR A GOOD PART OF THE WORK WEEK. AN UPPER
LEVEL DISTURBANCE WILL CROSS THE AREA LATER TODAY...BRINGING A
CHANCE OF SHOWERS TO THE REGION. TEMPERATURES SHOULD BE WELL ABOVE
NORMAL AT LEAST THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM MONDAY...
PRECIP JUST TO THE WEST OF THE FORECAST AREA SEEMS TO BE DRIVEN
MOSTLY BY A MID-LEVEL VORT MAX THAT MOST LIKELY DEVELOPED FROM THE
DEEP CONVECTION THAT OCCURRED ACROSS THE LA/MS GULF COAST REGION
THIS MORNING. THE LATEST RUC DATA...AS WELL AS OTHER MODELS...HAVE
PICKED THIS FEATURE UP RATHER WELL AND SHOWS IT PROGRESSING THROUGH
CENTRAL NC OVERNIGHT. IT APPEARS THE DPVA ASSOCIATED WITH THIS
FEATURE WILL PROVIDE ENOUGH FORCING AND DESPITE THE POOR
THERMODYNAMICS...SCATTERED SHOWERS WILL BE POSSIBLE. AS SUCH...MANY
OF THE LATEST HIGH RES SIMULATED REFLECTIVITY DATA (WRF NMM, WRF
ARW, HRRR, AMONG OTHERS) SHOW AN AREA OF LIGHT TO MODERATE PRECIP
MOVING THROUGH THE FORECAST AREA FROM WEST TO EAST OVERNIGHT AND
INTO TUESDAY MORNING...BEGINNING AROUND 03-06Z ACROSS THE WEST.
THEREFORE...WENT AHEAD AND INCREASED POPS TO HIGH END CHANCE ACROSS
THE ENTIRE FORECAST AREA OVERNIGHT. AT THIS TIME...IT APPEARS LITTLE
TO NO INSTABILITY WILL BE PRESENT DURING THE OVERNIGHT HOURS AND
THEREFORE...THUNDER SHOULD NOT BE A THREAT. ANOTHER SHORTWAVE WILL
APPROACH FROM THE WEST BY EARLY TUESDAY WHICH MAY ALSO ENHANCE THE
FORCING OVER THE AREA...BUT AT THIS TIME IT APPEARS THE BEST FORCING
ASSOCIATED WITH THIS WAVE WILL OCCUR AFTER SUNRISE (SEE SHORT TERM
DISCUSSION BELOW FOR MORE DETAILS). WITH MOSTLY CLOUDY OR OVERCAST
SKIES AND THE INCREASE IN LOW LEVEL MOISTURE...AM EXPECTING WARMER
OVERNIGHT LOWS TONIGHT...GENERALLY IN THE LOW TO MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM MONDAY...
TUESDAY:
AN AMPLIFYING SHORTWAVE IS EXPECTED TO PROGRESS EASTWARD ACROSS THE
CAROLINAS DURING THE DAY TUE...THOUGH THE EXACT TIMING REMAINS
SOMEWHAT UNCERTAIN. IN THE LOWER LEVELS...A PIEDMONT TROUGH DURING
IS PROGGED TO DEVELOP DURING PEAK HEATING. OTHERWISE...LIFT WILL BE
CONFINED TO VERY WEAK/BROAD LOW-LEVEL WARM ADVECTION AND MID-LEVEL
HEIGHT FALLS. W/REGARD TO THERMODYNAMICS...DESTABILIZATION WILL
LIKELY BE HAMPERED BY PERVASIVE CLOUD COVER THROUGH MUCH OF THE
DAY...PARTICULARLY EAST OF HIGHWAY 1. SOME CLEARING IS EXPECTED IN
THE WEST/NW PIEDMONT BY ~18Z IN THE PRESENCE OF A CONTINUED MOIST
BOUNDARY LAYER...AND INSTABILITY COULD ACTUALLY BE MORE FAVORABLE
WEST OF HWY 1. HOWEVER...SIGNIFICANT DRYING ALOFT IS ALSO EXPECTED
AS A MUCH DRIER MID/UPPER LEVEL AIRMASS ADVECTS INTO WESTERN
PORTIONS OF THE STATE TUE AFTERNOON...AND DRY AIR ENTRAINMENT MAY
OFFSET OR COMPLETELY NEGATE THE BENEFIT OF BETTER INSOLATION.
REGARDLESS...WITH WEAK MID-LEVEL LAPSE RATES OVER MOST OF THE AREA
(ASIDE FROM WEST/NW PIEDMONT) DURING PEAK HEATING...MLCAPE VALUES
WILL LIKELY NOT EXCEED 250-500 J/KG. WITH THE ABOVE IN MIND...EXPECT
SUFFICIENT FORCING AND INSTABILITY TO WARRANT AT LEAST A LOW CHANCE
(20-30%) OF SHOWERS/ STORMS...WITH THE BEST CHANCE OF THUNDER EAST
OF HIGHWAY 1. HOWEVER...IF FORCING ASSOC/W THE UPPER LEVEL WAVE IS
STRONG ENOUGH TO OVERCOME THE SIGNIFICANT AMOUNT OF DRY AIR ALOFT
PROGGED IN THE WEST/NW PIEDMONT...THUNDER WILL BE POSSIBLE THERE AS
WELL. GIVEN MARGINAL INSTABILITY...0-6 KM BULK SHEAR VALUES NO
HIGHER THAN 20-25 KT (BARELY SUPPORTIVE OF MULTICELLULAR
CONVECTION)...AND A RELATIVELY SHALLOW MIXED LAYER WITH LITTLE
POTENTIAL FOR EVAPORATIVELY ENHANCED DOWNDRAFTS...DO NOT ANTICIPATE
A SEVERE THREAT WITH ANY CONVECTION. EXPECT HIGHS ON TUE TO RANGE
FROM THE UPPER 60S/LOWER 70S IN THE EAST TO THE LOWER/MID 70S IN THE
WEST.
TUESDAY NIGHT:
SUBSIDENCE AND SHORTWAVE RIDGING BUILDING INTO THE AREA IN THE WAKE
OF THE SHORTWAVE SHOULD RESULT IN MOSTLY CLEAR SKIES TUE NIGHT.
GIVEN A WEAK/BAGGY MSLP GRADIENT AND THE CONTINUED PRESENCE OF A
MOIST BOUNDARY LAYER...ANTICIPATE A POTENTIAL FOR FOG ACROSS THE
AREA 06-12Z WED MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAINFALL
DURING THE DAY TUE. EXPECT LOWS IN THE LOWER/MID 50S. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...
AS SURFACE SYSTEM MOVES OFFSHORE EARLY WEDNESDAY...WARM AIR WILL BE
SPREADING NORTH DUE TO SUBTROPICAL RIDGING INTO THE SOUTHERN PLAINS
AND WESTERN GULF STATES. HIGHS WEDNESDAY WILL BE 15 TO 20 DEGREES
ABOVE NORMAL...UPPER 70S OVER MOST OF THE AREA. MOISTURE WILL BE
BUILDING NORTH INTO THE TENNESSEE VALLEY AND POOLING ON THE WESTERN
SLOPES AS THE RIDGE HOLDS TIGHT THROUGH THURSDAY...INSTABILITY WILL
BE MINIMAL AND CAPPED...PROVIDING ANOTHER WARM DRY DAY WITH HIGHS IN
THE UPPER 70S TO LOWER 80S AFTER MILD MORNING LOWS IN THE LOWER 50S.
A MID LEVEL WAVE ORIGINATING IN THE SOUTHERN PLAINS WILL BE
DAMPENING THE RIDGE AMPLITUDE WITH WEAK SURFACE HIGH PRESSURE
SHIFTING OFFSHORE. THIS WILL PRODUCE A SLIGHT CHANCE OF SHOWERS
THURSDAY NIGHT...WITH A LITTLE BETTER CHANCES ON FRIDAY AS A WEAK
SURFACE FRONT EDGES VERY SLOWLY SOUTH AND EAST INTO THE MID ATLANTIC
REGION. PROGGED INSTABILITY IS SUFFICIENT FOR THUNDER GIVEN THE LOW
LEVEL FORCING AS HIGHS FRIDAY WILL STILL BE ON THE WARM SIDE...MID
TO UPPER 70S.
THE SURFACE FRONT WILL SAG FURTHER SOUTH ON SATURDAY AS LOW PRESSURE
AREA DEVELOPS OFF THE MID ATLANTIC COAST...WILL MAINTAIN SLIGHT
CHANCE TO CHANCE POPS ACROSS THE AREA THROUGH SATURDAY...AGAIN WITH
A CHANCE OF THUNDER GIVEN THE WARM AIRMASS AND POTENTIAL FOR THE
FRONT TO STALL OVER THE AREA. HIGHS WILL STILL BE IN THE MID TO
UPPER 70S.
THE FRONTS WILL BE SHOVED SOUTH OF THE AREA...SATURDAY NIGHT OR
SUNDAY AND WILL MAINTAIN SLIGHT CHANCES TO COVER THE TIMING
UNCERTAINTY. HIGH PRESSURE WILL WEDGE DOWN THE COAST SUNDAY/MONDAY
AND WILL TAPER OFF THE POPS SUNDAY NIGHT AND LEAVE MONDAY DRY FOR
NOW. HIGHS SUNDAY WILL BE IN THE LOW TO MID 70S WITH COOLER TEMPS IN
THE NORTHEAST WITH LINGERING CLOUD COVERAGE AND COOL AIR WEDGING
IN...WITH HIGHS ON MONDAY A TOUCH COOLER...LOWER 70S ACROSS THE
AREA.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 200 AM TUESDAY...
LIGHT RAIN IS MOVING FROM KINT/KGSO TO JUST NORTH OF KRDU/KRWI...BUT
THE RAIN HAS BEEN LIGHT AND CEILINGS HAVE REMAINED ABOVE 3K FT.
MOST OBSERVING SITES OVER THE WESTERN PIEDMONT ARE STILL REPORTING
3-4K FT CEILINGS...SO IT IS UNCERTAIN AT THIS TIME HOW LOW CEILINGS
WILL GET BEFORE SUNRISE. A PERIOD OF MVFR CONDITIONS WILL STILL BE
REFLECTED IN THE CURRENT TAF. IF CEILINGS DO FALL TO MVFR...THEY
SHOULD HOLD RELATIVELY CLOSE TO 3K FT THROUGH THIS AFTERNOON AS LOW
LEVEL MOISTURE REMAINS HIGH AND MIXING IS SHALLOW. AN UPPER LEVEL
DISTURBANCE WILL CROSS THE AREA FROM WEST TO EAST THIS AFTERNOON
AND MAY SPARK A FEW ISOLATED SHOWERS OR STORMS....MAINLY OVER THE
WESTERN PIEDMONT. HOWEVER... CONFIDENCE IN TIMING AND LOCATION IS
MUCH TOO LOW FOR MENTION IN THE CURRENT TAF. CLEARING SKIES AFTER
00Z AND LIGHT WINDS WILL PROMOTE FOG DEVELOP TONIGHT...MOST LIKELY
AFTER 06Z.
BEYOND THE 00Z VALID TAF PERIOD...VFR CONDITIONS ARE EXPECTED TO
PREVAIL EACH DAY...BUT A PERIOD OF FOG/STRATUS IS POSSIBLE DURING
THE MORNING HOURS. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE FRIDAY
AFTERNOON INTO SATURDAY DUE TO AN UPPER-LEVEL DISTURBANCE AND WEAK
SURFACE LOW PRESSURE MOVING THROUGH THE AREA.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...KRR
SHORT TERM...VINCENT
LONG TERM...MLM
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
345 AM CDT TUE MAR 13 2012
.SHORT TERM...
RELATIVELY QUIET PERIOD AS STRONG WAVE CRASHES PAC NORTHWEST THEN
MOVES INTO SASKATCHEWAN TONIGHT. THE RESULTANT LOW PRESSURE
GRADIENT WILL TIGHTEN UP AND MAKE IT SOMEWHAT BREEZY TODAY.
BETWEEN YESTERDAYS RAIN AND RECENT WARM TEMPERATURES SNOW PACK IS
ALL BUT GONE...SO WITH PLENTY OF SOLAR EXPECT ANOTHER WARM DAY.
MODELS IN DECENT AGREEMENT WITH WARM AIR MOVING NORTH TODAY. TODAYS
RECORD HIGH FOR GFK IS 51F AND FGF IS 55F. HAVE NEAR 60F IN GRIDS
SO EXPECT RECORDS TO FALL AGAIN. FAR IS 64 SO WILL BE CLOSE THERE.
BOUNDARY LAYER WINDS CRANK UP TO 20-25 KTS WITH 850 WINDS TO 40KTS
IN NAM AND GFS. LOWER LAYERS FAIRLY STABLE AS COOLER AIR RETREATS
AND DIRECTIONAL COMPONENT NOT OPTIMAL...SO EXPECT GUSTS TO 30 KTS
WEST OF VALLEY IN FAVORED HIGH TERRAIN. ON-LINE VERSION HRRR HAD
BEEN CONSISTENT IN GUSTS TO 35 KNOTS KABC TO KDVL...WITH LATEST
RUNS BACKING OFF. HAVE NEAR 30 KT GUSTS IN GRIDS ALONG WEST
VALLEY SO DO NOT ANTICIPATE WIND ADVISORY ATTM.
WINDS DIMINISH TONIGHT AS TROUGH REACHES DVL BASIN AROUND 06Z AND
THERMAL RIDGE MOVES INTO RRV. DRY AIR...CLEAR SKIES AND WARM AIR
ALOFT...HAVE UPPED MINS DUE TO THE WARMER AIR ALOFT KEEPING
TEMPERATURES A BIT HIGHER. WIND SHIFT PASSES AROUND SUNRISE
WEDNESDAY. WITH ONLY SLIGHT COOLING...ABOUT 4C TO 6C...EXPECT ONLY A
FEW DEGREES COOLER WEDNESDAY. THIS MAY WELL KEEP US FROM HAVING
ANOTHER RECORD WARM DAY.
SURFACE HIGH SETTLES OVER VALLEY WEDNESDAY NIGHT...WITH MAINLY
CLEAR SKIES AND CALM WINDS BY THURSDAY MORNING. DUE TO LOSS OF
SNOW...WET SOILS AND A BIT MORE CLOUD COVER KEPT MINS ABOVE 32F
MOST AREAS. COULD BE FOG THURSDAY MORN BUT WILL ASSESS THAT
POTENTIAL LATER. RETREATING HIGH AND FAIR AMOUNT OF SOLAR AGAIN
SO EXPECT ANOTHER UNSEASONALLY WARM DAY.
.LONG TERM (FRIDAY-MONDAY)...ENSEMBLES AND OPERATIONAL MODELS IN
AGREEMENT WITH DEVELOPING EASTERN CONUS RIDGE AND WESTERN CONUS
TROUGH. AS THIS PATTERN DEVELOPS THERE WILL LIKELY BE A SURGE OF
MOISTURE/INSTABILITY BY SUNDAY. NEIGHBORING OFFICES DECIDED THAT A
DRY FORECAST WOULD BE BEST THROUGH SUNDAY NIGHT GIVEN NO STRONG
FORCING MECHANISM REPRESENTED BY THE MODELS. ALTHOUGH ISOLATED
THUNDER APPEARS POSSIBLE...FOLLOWED WITH THE NEIGHBORS. ON
MONDAY...GFS IS A BIT FURTHER EAST WITH OVERALL PATTERN COMPARED
WITH THE ECMWF. GFS PLACES A FRONTAL BOUNDARY THROUGH THE FA (WET)
WHILE THE ECMWF HAS UPPER RIDGING (DRY). KEPT THE THUNDER CHANCES IN
THE FORECAST FOR MONDAY. TEMPERATURES WILL CONTINUE ABOVE NORMAL.
&&
.AVIATION...
SO FAR...BR HAS YET TO DEVELOP EAST OF VALLEY AS WINDS STAYING UP
JUST ENOUGH. IF IT DOES DEVELOP SHOULD DISSIPATE QUICKLY...SO DO
NOT PLAN ON PUTTING IT IN UPDATES. WIND GUSTS TO NEAR 30 KTS
POSSIBLE KDVL AND 25 KTS KFAR/KGFK 17Z-21Z. SLIGHTLY LOWER
EXPECTED EAST OF VALLEY...BUT WILL NEED TO MONITOR DEPENDENT ON
EXTENT OF MIXING.
&&
.HYDROLOGY...
WARM TEMPERATURES THE PAST FEW DAYS HAVE ALL BUT ELIMINATED THE
SNOW PACK ACROSS THE REGION. AS A RESULT MINOR RISES HAVE BEEN
SHOWING UP ON AREA RIVERS. MONDAYS RAINFALL TOTALS...BASED ON
REPORTS AND 88D ESTIMATES...WERE GENERALLY LESS THAN ONE HALF
INCH. ISOLATED AMOUNTS UP TO ONE INCH IN THE LOWER SHEYENNE AND
UPPER SNAKE BASED ON THE 88D WILL NEED TO BE VERIFIED. WITH THE
WARM TEMPERATURES FORECAST THIS WEEK ABOUT THE ONLY SNOW THAT WILL
BE LEFT SHOULD BE IN TOWNS AND SHELTERED AREAS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
EWENS/TG
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
317 AM CDT TUE MAR 13 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH
SURFACE LOW NORTH OF LAKE HURON WILL PUSH EAST AS HIGH PRESSURE FROM
WESTERN MINNESOTA TO MISSOURI MOVES INTO WISCONSIN DURING THE LATE
AFTERNOON AND EARLY EVENING. THE WEST WINDS AROUND 28 KNOTS AT
1 THSD FT DIMINISH TO 15 KNOTS BEFORE LAPSE RATES STEEPEN TO 9.5
C/KM FROM 900 MB DURING THE EARLY AFTERNOON. THEREFORE ONLY A
NARROW WINDOW FOR GUSTS TO AROUND 20 TO 25 MPH AROUND NOON.
THINK THERE WILL BE A LAKE BREEZE IN THE AFTERNOON...ESPECIALLY LATE
AS THE SURFACE HIGH APPROACHES LAKE MICHIGAN. LOCAL 4KM MESO MODEL
KEEPS A WEST/NORTHWEST SURFACE FLOW THROUGH 18Z...THE FARTHEST THE
MODEL RUNS. HOWEVER THE HRRR DOES BEGIN TO BRING SOME ONSHORE WINDS
SOUTH OF MILWAUKEE. EXPECT LATER MESO RUNS WILL SHOW SOME LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON. EVEN SO...TEMPS WILL HAVE
WARMED QUITE A BIT BY THE TIME THE LAKE BREEZE WOULD PUSH
INLAND...SO WENT WITH MILD HIGH TEMPS ALL THE WAY TO THE
LAKESHORE...THEN FALLING DURING THE MID AFTERNOON.
850 MB WARM AIR ADVECTION BEGINS ESPECIALLY OVER SOUTH CENTRAL
WISCONSIN LATER IN THE AFTERNOON AND CONTINUING TONIGHT.
LACK OF MOISTURE SO LITTLE IN WAY OF ALTOCUMULUS CLOUDS EXPECTED.
DRY LOW LEVELS SO FEW IF ANY CUMULUS.
WARM AIR ADVECTION CONTINUES OVERNIGHT. 925/850 MB MOISTURE
INCREASES TOWARD SUNRISE...ESPECIALLY OVER SOUTH CENTRAL WISCONSIN
AS 850 MB WINDS INCREASE TO 35 KNOTS.
WEDNESDAY - CONFIDENCE...MEDIUM
BROAD ANTICYCLONIC UPPER FLOW WITH WARM SOUTHWEST WINDS BRINGING 925
TEMPS INTO THE 17-19C RANGE. THIS SUGGESTS TEMPS WELL INTO THE 70S
QUITE PLAUSIBLE. MOS GUIDANCE LOOKS TOO COLD AS DO THE 2 METER
TEMPS. BUFKIT MIXED SOUNDINGS LOOK MORE REASONABLE AND MATCHES UP
BETTER WITH 925 TEMP TECHNIQUE.
WEDNESDAY NIGHT - CONFIDENCE...MEDIUM
SURFACE FRONT PUSHES ACROSS SRN WI WITH A RELATIVELY WEAK VORT LOBE.
DECENT INSTABILITY ABOVE 700 MILLIBARS WITH INITIAL LOW LEVEL
NEGATIVE AREA ON SOUNDING...MORE PRONOUNCED ON GFS. BUT THE CAP DOES
ERODE SOME INTO THE OVERNIGHT HOURS. WONDERING WHAT TO MAKE OF THE
CONSENSUS OF MOS SHOWING DENSE FOG DEVELOPMENT. IF WE GET SOME
SHOWERS/STORMS...FLOW DOES BECOME BAGGY SO FOG POTENTIAL DOES HAVE
SOME MERIT.
THURSDAY - CONFIDENCE...MEDIUM
EAST/WEST BOUNDARY LINGERS NEAR SRN WI. BULK OF MODELS SUGGEST QPF
IN THE SOUTHEAST CWA...IN LINE WITH GOING FORECAST. NAM SOUNDING
MUCH MORE ROBUST THAN THE GFS. NAM SHOWS CAPES OVER 1K WITH INVERTED
V LOOK TO SOUNDING. TEMPS HIGHLY DEPENDENT ON FRONTAL PLACEMENT AND
POTENTIAL FOR MORE LAKE INFLUENCE. 925 TEMPS STILL TOASTY. SO INLAND
AREAS THAT SEE SUN SHOULD MAKE THE 70S ONCE AGAIN.
FRIDAY THROUGH MONDAY - CONFIDENCE...LOW TO MEDIUM
CONSENSUS FROM SURROUNDING OFFICES IS TO GO WITH THE DRY LOOK RATHER
THAN THE SLIGHT POPS. UPPER RIDGE GRADUALLY BUILDS UP. APPEARS
FORCING WILL STAY WEST OF THE AREA CLOSER TO HIGHLY AMPLIFIED/SLOW
MOVING DEEP TROUGH. NOT A SLAM DUNK ON THIS AS MODELS SHOW A FEW
WEAK VORTS FLOATING BY HERE AND THERE BUT THINKING WAS TO JUST GO
DRY RATHER THAN HAVE SLIGHTS SPLASHED EVERYWHERE. UNSEASONABLE
WARMTH GOES ON AND ON.
&&
.AVIATION/12Z TAFS/...AFTER LINGERING PATCHES OF STRATOCUMULUS CLEARS
EARLY THIS MORNING ONLY FEW-SCATTERED CU EXPECTED WITH VFR CONDITIONS
EXPECTED THIS MORNING AND AFTERNOON AS HIGH PRESSURE PUSHES INTO
WISCONSIN LATE THIS AFTERNOON AND EVENING.
&&
.MARINE...WEST TO NORTHWEST WINDS WILL DIMINISH AS HIGH PRESSURE
PUSHES ACROSS LAKE MICHIGAN THIS EVENING. EXPECT A LAKE BREEZE TO
DEVELOP LATER THIS AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
WEDNESDAY THROUGH MONDAY...COLLAR
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
305 AM CDT TUE MAR 13 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE MOVING EAST OVER SOUTHERN ONTARIO EARLY THIS MORNING WHILE
WEAK HIGH PRESSURE IS SHIFTING INTO THE NORTHERN MISSISSIPPI
VALLEY. LOW CLOUDS ARE IN THE PROCESS OF EXITING NE WISCONSIN...AND
ONLY HIGH CIRRUS IS PUSHING ACROSS THE DAKOTAS UPSTREAM. LOW LEVELS
ARE QUITE DRY THERE...AND THIS DRY AIRMASS WILL MOVE INTO THE REGION
TODAY. FORECAST CONCERNS ARE RELATIVELY MINIMAL FOR THIS TIME OF
THE YEAR...AND INCLUDE MIN HUMIDITIES TODAY...AND TEMPERATURES TODAY
AND TOMORROW.
TODAY...SHORTWAVE TROUGH OVER SOUTHEAST ONTARIO WILL LIFT NE...WHILE
A SHEARED WAVE OVER THE ARROWHEAD MOVES EAST OVER LAKE SUPERIOR.
DESPITE THE SHORTWAVES ALOFT PASSING NEARBY...CYCLONIC FLOW AT THE
SURFACE WILL BE ABATING...WHILE A WEAK RIDGE AXIS SHIFTS INTO THE
REGION THIS AFTERNOON. DRIER AIR OVER THE NORTHERN PLAINS WILL BE
PUSHING ACROSS THE AREA EARLY THIS MORNING...AND THE MVFR STRATUS
WILL BE EXITING NE WISCONSIN BY 09Z OR SO. A VERY DRY AIRMASS WILL
THEN BE IN PLACE FOR THE REST OF THE DAY. THOUGH MIXING MAY ONLY
REACH TO AROUND 900MB...WINDS SHOULD ALLOW FOR DRY AIR ABOVE THE
INVERSION TO CRASH TO THE SURFACE...ESPECIALLY OVER NORTHERN AND FAR
NORTHEAST WISCONSIN WHERE THE GRADIENT WILL BE THE TIGHTEST. HAVE
LOWERED DEWPOINTS TO THE MID TEENS UP NORTH...WHICH GIVES RH/S IN
THE 20-25 PCT RANGE. BOTH THE NAM AND GFS AGREE THAT 925MB TEMPS
WILL RANGE FROM 5-10C ACROSS THE AREA...WHICH CORRESPONDS THE MOST
WITH THE BCCONSRAW AND ECMWBC...THAT GIVES HIGHS RANGING FROM THE
MID 50S NORTH TO MID 60S SOUTH.
TONIGHT...RIDGING WILL BE PASSING OVERHEAD ACROSS THE REGION. WILL
SEE CLEAR TO MOSTLY CLEAR SKIES WITH LIGHT WINDS IN THE EVENING
BECOMING SOUTHEASTERLY. AXIS OF LOW LEVEL MOISTURE WILL GET DRAWN
NORTHWARD INTO CENTRAL WISCONSIN LATE. WITH LOW LEVEL TEMPS ALSO
WARMING AND NO SIGNS OF STRATUS UPSTREAM...THINK POSSIBILITIES OF
LOW STRATUS IS RELATIVELY LOW. LOWS RANGING FROM THE MID 30S
NORTH...TO THE MID 40S SOUTH.
WEDNESDAY...STRONG SHORTWAVE TROUGH WILL BE LIFTING NE OVER CENTRAL
CANADA...WHILE ITS COLD FRONT SAGS INTO NORTHWEST WISCONSIN IN THE
AFTERNOON. AHEAD OF THE FRONT...SOUTHWEST WINDS WILL ADVECT A VERY
WARM AND RELATIVELY MOIST AIRMASS INTO THE REGION. SLIGHTLY BACKED
SE WINDS WILL KEEP FAR NE WISCONSIN A LITTLE COOLER THAN THE REST OF
THE STATE...AND WILL GO WITH HIGHS IN THE UPPER 60S NORTH TO THE
MIDDLE 70S SOUTH. TEMPS MAY STRUGGLE TO GET OUT OF THE 50S ALONG
THE LAKESHORE THOUGH. WEAK CONVERGENCE ALONG THE FRONT COMBINED
WITH A LACK OF UPPER SUPPORT SHOULD KEEP THE FRONT INACTIVE TOMORROW
AFTERNOON SO NO REAL SHOWER OR THUNDER THREAT FORESEEN.
.LONG TERM...WEDNESDAY NIGHT THRU MONDAY. MAIN FORECAST CONCERN IS
HOW HIGH TO GO WITH TEMPS...AND PINNING DOWN BEST CHANCE FOR
SHOWERS/STORMS.
SW FLOW ALOFT WILL CONTINUE THROUGH THE PERIOD...WITH NO COLD AIR
IN SIGHT. TEMPS ALOFT ACTUALLY DO NOT CHANGE MUCH...WITH ONLY A
SLIGHT RISE IN HEIGHTS THIS WEEKEND AND EARLY NEXT WEEK AS THE
UPPER RIDGE BUILDS NORTH INTO ONTARIO. EXPECT 60S FOR MOST
LOCATIONS...WITH SOME 70S POSSIBLE ACROSS CENTRAL WI AND THE FOX
VALLEY NEXT WEEK. SEVERAL RECORDS ARE LIKELY TO FALL. ONLY
EXCEPTION TO THE VERY MILD AIR WILL BE ALONG THE LAKESHORE...AS A
SE SURFACE FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS IN THE UPPER
40S AND 50S THROUGH MOST OF THE PERIOD.
FIRST CHANCE FOR SHOWERS/ISO STORMS WILL BE WEDNESDAY NIGHT AS A
WEAK FRONTAL BOUNDARY CROSSES THE AREA. NOT MANY POSITIVES TO GET
SHOWER/STORM ACTIVITY GOING...AS SURFACE CONVERGENCE IS WEAK AND
VERY LITTLE IF ANY UPPER LEVEL SUPPORT...PLUS BETTER MOISTURE
FORECAST TO BE JUST SOUTH/WEST OF THE AREA. THERE WILL BE FAIRLY
STEEP MID-LEVEL LAPSE RATES...ESPECIALLY ACROSS EASTERN WI...SO
WILL CONTINUE WITH HIGHER POPS THERE...BUT KEPT THE CHANCES LOW.
PREVIOUS ECMWF SHOWED A SHORTWAVE OVER THE NORTHERN PLAINS
THURSDAY...AND TOOK THIS FEATURE OVER LAKE SUPERIOR THURSDAY
NIGHT. THIS WOULD HAVE BROUGHT A DECENT CHANCE FOR PRECIP ACROSS
THE NORTH...HOWEVER LATEST RUN AS WELL AS OTHER MODELS AND
ENSEMBLES HAVE RIDGING AND WITH NOT MUCH UPPER SUPPORT OR
MOISTURE...WILL LEAVE THURSDAY NIGHT DRY. IF THIS SHORTWAVE
MATERIALIZES AND SLOWS A LITTLE...PASSING OVER THE AREA ON
FRIDAY...WE COULD GET SOME ACTIVITY TO DEVELOP...BUT THINK THIS IS
UNLIKELY WITH THIS PATTERN. AS WE WORK INTO THIS WEEKEND AND
EARLY NEXT WEEK...TIMING BEST CHANCES FOR SHOWERS/STORMS WILL BE
DIFFICULT AS SYNOPTIC PATTERN DOES NOT SUPPORT PRECIP. MODELS SHOW
POTENTIAL FOR WEAK SHORTWAVES MOVING THROUGH THE PLAINS AND GREAT
LAKES IN THE SW FLOW ALOFT...WHICH WOULD BRING A CHANCE OF
SHOWERS/STORMS. AFTER COORDINATION WITH SURROUNDING OFFICES...WENT
DRY FRIDAY-TUESDAY AS NO PERIOD LOOKS MORE LIKELY THAN THE OTHER
FOR SMALL CHANCE POPS AND UPPER RIDGE BUILDS OVERHEAD. BETTER
CHANCE FOR WIDESPREAD ACTIVITY LOOKS TO ARRIVE MID TO LATE NEXT
WEEK AS CLOSED UPPER LOW EJECTS OUT INTO THE PLAINS.
&&
.AVIATION...CLDS PROGRESSING EWD ABOUT AS EXPECTED. CLDS SHOULD
CONT TO DECR FM W-E OVERNIGHT AS UPR LOW PULLS AWAY. THEN EXPECT
VFR CONDITIONS THRU TOMORROW.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/BERSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 PM CDT MON MAR 12 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY
303 PM CDT MON MAR 12 2012
CURRENTLY AS OF 19Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT
ANALYSIS SHOWED SOUTHWEST FLOW FROM THE PACIFIC NORTHWEST TO
HUDSON BAY... WITH A SHORTWAVE TROUGH OVER SASKATCHEWAN. IN THE
SOUTHERN STREAM...AN UPPER LOW WAS NEAR EAU CLAIRE WITH A
SHORTWAVE ROUNDING ITS BASE OVER NORTHERN ILLINOIS. THIS LATTER
SHORTWAVE IS HELPING TO SUSTAIN SHOWERS AND A FEW THUNDERSTORMS
OVER SOUTHEAST WISCONSIN AND NORTHERN ILLINOIS...AIDED BY DAYTIME
HEATING. OTHER SHOWER ACTIVITY WAS OVER NORTHERN AND CENTRAL
WISCONSIN...AIDED BY DPVA FORCING AHEAD OF THE UPPER LOW. ANOTHER
AREA OF SHOWERS WERE WEST OF MINNEAPOLIS IN THE DEFORMATION ON THE
BACK SIDE OF THE UPPER LOW. THERE HAS BEEN SOME PARTIAL CLEARING
TODAY SOUTH OF I-90...THANKS TO DRY AIR WRAPPING AROUND THE UPPER
LOW. THIS CLEARING COMBINED WITH A WARM LAST NIGHT HAS ALLOWED
TEMPERATURES TO CLIMB MOSTLY INTO THE 50S...DESPITE 850MB TEMPS
WHICH HAVE DROPPED TO 2-4C PER RUC ANALYSIS...AND THE 3C READING
AT OAX AT 12Z. MUCH WARMER AIR AT 850MB EXISTS OVER THE
DAKOTAS...THOUGH...WITH READINGS OF 12C AT BIS AND UNR AT 12Z.
TONIGHT AND TUESDAY...THE UPPER LOW OVER WESTERN WISCONSIN IS
PROGGED TO CONTINUE ITS NORTHEASTWARD TREK...LIFTING INTO NORTHEAST
ONTARIO BY 12Z TUESDAY. IT APPEARS THIS UPPER LOW WILL THEN SLOW
DOWN...DUE TO THE CURRENT SHORTWAVE TROUGH IN SASKATCHEWAN WHICH
MODELS HAVE IT PHASING WITH THE UPPER LOW. THE ONLY IMPACTS THIS
PHASING HAS ON OUR FORECAST AREA IS NORTH OF I-94 TUESDAY
MORNING...WHERE SLIGHTLY COOLER AND DRIER AIR WILL MOVE IN.
OTHERWISE...850MB TEMPS ARE PROGGED TO BE ON THE RISE THROUGHOUT
THIS TIME PERIOD. AT 12Z TUESDAY...THEY SHOULD RANGE FROM
4-8C...THEN RISE TO 8-12C BY 00Z WEDNESDAY. THIS WARMING COMBINED
WITH CLEARING SKIES AND DRIER AIR FOR TUESDAY SHOULD RESULT IN
DECENT MIXING. STAYED TOWARD THE HIGH END OF GUIDANCE FOR HIGHS
WHICH PUTS THEM CLOSE TO OR ABOVE RECORD VALUES. REGARDING TONIGHTS
LOWS...PRECIPITABLE WATER VALUES ARE FORECAST TO DROP TO 0.25 INCH
BY 12Z OR LOWER AFTER BEING UP BETWEEN 0.5-0.75 INCHES. THIS DRY AIR
SHOULD HELP TEMPERATURES DROP...THOUGH WINDS KIND OF STAY UP THROUGH
MUCH OF THE NIGHT UNTIL LATE. THEREFORE HAVE TAKEN A BLEND OF
GUIDANCE APPROACH. COULD HAVE SOME PATCHY FOG WHERE WINDS CAN
DECOUPLE DUE TO RECENT RAINS...WHILE THE OVERALL WIND ESPECIALLY
RIGHT ABOVE THE SURFACE KEEPS THE FOG FROM BECOMING MORE WIDESPREAD.
TUESDAY NIGHT THROUGH THURSDAY...A BIG CHUNK OF THE UPPER TROUGHING
CURRENTLY OFF THE PACIFIC NORTHWEST COAST IS FORECAST TO LIFT OUT
INTO SOUTHWEST CANADA TUESDAY NIGHT...THEN UP TO HUDSON BAY BY
WEDNESDAY NIGHT. A STRONG LOW PRESSURE SYSTEM DEVELOPS FROM THIS
UPPER TROUGHING...THOUGH AGAIN WELL OFF TO OUR NORTH. HOWEVER...
THERE ARE GOING TO BE SOME IMPACTS FROM IT. FIRST...A SURGE OF WARM
AIR CAUSED BY DOWNSLOPING OFF THE ROCKIES WILL MOVE INTO THE AREA.
THE FIRST FEELING OF THIS COMES TUESDAY NIGHT AS INCREASING
SOUTHEAST TO SOUTH WINDS BRING HIGHER DEWPOINTS AND 850MB TEMPS RISE
TO 12-14C. THIS SITUATION MAY KEEP TEMPERATURES FROM FALLING BELOW
50 ALONG AND WEST OF THE MISSISSIPPI RIVER. ON WEDNESDAY...WINDS
TURN SOUTHWEST AHEAD OF THE LOW PRESSURE SYSTEMS COLD FRONT
CROSSING MINNESOTA. THERE ARE INDICATIONS FROM THE 12.12Z NAM/ECMWF
THAT 850MB TEMPS COULD EVEN RISE TO 16C OVER NORTHEAST IOWA...ALMOST
3 STANDARD DEVIATIONS ABOVE NORMAL. WITH PLENTY OF SUN AND A WARM
START...TEMPERATURES SHOULD EASILY CLIMB INTO THE 70S. AN 80F
READING MAY EVEN OCCUR (NOTE 81F HIGH FOR SPARTA OFF MET GUIDANCE).
DEWPOINTS ARE ALSO EXPECTED TO CLIMB INTO THE 50S WITH A GOOD FETCH
COMING OUT OF THE GULF OF MEXICO. THE COMBINATION OF THE
UNPRECEDENTED WARMTH AND DEWPOINTS WILL LIKELY LEAD TO CUMULUS
DEVELOPMENT...MAKING IT FEEL MORE LIKE LATE SPRING THAN MID MARCH.
FOR WEDNESDAY NIGHT INTO THURSDAY...THE UPPER FLOW TURNS A LITTLE
MORE TOWARDS WEST...ENOUGH TO ALLOW THE WEAKENING COLD FRONT TO MOVE
INTO THE FORECAST AREA. BELIEVE THE 12.12Z NAM IS TOO AGGRESSIVE ON
THE SPEED GIVEN THE 12.12Z GFS/UKMET/ECMWF SLOWER. IN ANY EVENT...
THE FRONT WILL RE-ORIENT ITSELF WEST-EAST...LIKELY OCCURRING ON
THURSDAY NEAR OR JUST SOUTH OF I-90. CONVECTIVE INITIATION ON THE
FRONT DOES NOT SEEM LIKELY...DUE TO CAPPING. THE 12.12Z GFS DOES TRY
TO SPIT OUT THESE VERY LIGHT QPF VALUES...BUT THIS IS MORE FROM THE
MODEL BRINGING IN TOO MUCH LOW LEVEL MOISTURE AND GENERATING
STRATUS/DRIZZLE VERSUS CONVECTION. EVEN THEN...THE PATTERN DOES NOT
FAVOR STRATUS/DRIZZLE AND THE MODEL SEEMS TO HAVE A HIGH MOISTURE
BIAS. EVEN WITH THE FRONTAL PASSAGE...850MB TEMPS ONLY DROP TO
10-12C SO THURSDAY MAY ONLY END UP A LITTLE COOLER THAN WEDNESDAY.
WEDNESDAY NIGHT ALSO LIKELY STAYING MILD...ESPECIALLY AHEAD OF THE
FRONT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
303 PM CDT MON MAR 12 2012
MAIN STORY REMAINS THE UNPRECEDENTED WARMTH WHICH LOOKS TO PERSIST
THROUGH THE ENTIRE LONG TERM PERIOD AND BEYOND.
VERY GOOD MODEL AGREEMENT EXISTS THAT A DEEP UPPER LEVEL TROUGH IS
GOING TO DEVELOP ALONG THE WEST COAST OF THE U.S. FRIDAY INTO
SATURDAY. AS A RESULT...RIDGING BUILDS DOWNSTREAM OVER THE CENTRAL
AND EASTERN U.S.. THIS RIDGE BECOMES QUITE STRONG AND ACCORDING TO
THE CFS V2 MODEL...IT MAY PERSIST RIGHT THROUGH THE END OF THE
MONTH...WHILE THE WEST COAST TROUGH STAYS PUT OR CUTS-OFF. SINCE THE
CFS HAS BEEN DOING VERY WELL OVER THE PAST FEW MONTHS...HAVE
PREFERRED MODEL SCENARIOS WHICH KEEP THE WESTERN TROUGH IN
PLACE...WHICH LUCKILY MOST MODELS DO INCLUDING THE NEW 12.12Z ECMWF.
FOLLOWING THIS IDEA...850MB TEMPS THROUGHOUT THE LONG TERM PERIOD
STAY BETWEEN 10-14C OR 2-2.5 STANDARD DEVIATIONS ABOVE NORMAL. THIS
WOULD MEAN HIGHS NEAR OR ABOVE RECORD HIGHS. HAVE ADJUSTED ALL HIGH
TEMPERATURES TOWARDS THE HIGH END OF GUIDANCE. A PERSISTENT SOUTH
WIND OF 20-40 KT AT 925MB WILL HELP TO KEEP A PULL OF MOISTURE OUT
OF THE GULF OF MEXICO...THOUGH LACK OF VEGETATION AND THE DISTANCE
FROM THE GULF SHOULD HOLD DEWPOINTS BELOW 60. WITH THE WARM
TEMPERATURES AND DEWPOINTS...ANTICIPATING A LOT OF PARTLY SUNNY DAYS
DUE TO CUMULUS DEVELOPMENT.
PRECIPITATION CHANCES ARE VERY UNCERTAIN AND IT IS ENTIRELY POSSIBLE
THAT THE WHOLE LONG TERM PERIOD ENDS UP DRY. HOWEVER...WITH THE WELL
ABOVE NORMAL DEWPOINTS INTERACTING WITH WEAK SHORTWAVES COMING OUT
OF THE PACIFIC THROUGH THE BUILDING RIDGING...CANNOT RULE OUT A FEW
PERIODS OF SHOWERS AND THUNDERSTORMS. HAVE 20-30 PERCENT CHANCES
THROUGHOUT MUCH OF THE LONG TERM AS A RESULT. MUST BE STRESSED THAT
MUCH OF THIS PERIOD WILL LIKELY BE DRY.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1149 PM CDT MON MAR 12 2012
IR SATELLITE SHOWING BACK EDGE OF MVFR/VFR STRATOCUMULUS PUSHING
EAST OF THE MISSISSIPPI RIVER NOW AS A RIDGE OF HIGH PRESSURE
BUILDS IN FROM THE PLAINS. CLEAR SKIES AND LIGHT WINDS NEAR THE
RIDGE AXIS MAY PRODUCE SOME PATCHY FOG ACROSS PORTIONS OF
SOUTHEAST MN INCLUDING KRST IN THE 10-13Z TIME FRAME...BUT
CONFIDENCE IS NOT HIGH DUE TO LIGHT WESTERLY COMPONENT TO THE
SURFACE WIND. WILL CONTINUE MENTION OF SOME LIGHT 6SM BR IN THAT
TIME FRAME. OTHERWISE...VFR/CLEAR CONDITIONS EXPECTED THROUGH
TUESDAY EVENING. LOOK FOR LIGHT WESTERLY WINDS IN THE 5 TO 10KT
RANGE TO BACK TO THE SOUTH TODAY AS THE RIDGE AXIS SHIFTS EAST OF
THE REGION.
&&
.CLIMATE...THROUGH EARLY NEXT WEEK
303 PM CDT MON MAR 12 2012
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED THROUGHOUT MUCH OF THE
NEXT 7 DAYS AND LIKELY BEYOND. AT LA CROSSE AND ROCHESTER...THE NEXT
3 DAYS APPEAR TO BE RELATIVE MINIMUMS FOR WHAT THE GOING RECORDS
ARE...SO ANY OF THE DAYS WILL HOLD A CHANCE FOR BREAKING THE RECORD.
WEDNESDAY STILL LOOKS LIKE THE WARMEST DAY OF THE WEEK AND HOLDS THE
HIGHEST POTENTIAL FOR BREAKING THE RECORDS WITH HIGHS EXPECTED IN
THE 70S. A FEW PLACES COULD EVEN APPROACH 80. HEADING INTO THE
WEEKEND AND EARLY NEXT WEEK...RECORDS VARY IN TERMS OF HOW HIGH THEY
ARE...BUT DEFINITELY POTENTIAL EXISTS FOR MORE RECORDS TO BE BROKEN.
SEE OUR WEBSITE FOR A LISTING OF RECORD HIGHS THROUGH EARLY NEXT
WEEK.
&&
.HYDROLOGY...
1232 PM CDT MON MAR 12 2012
ACCORDING TO OFFICIALS THERE HAVE BEEN SOME LOCALIZED ICE BLOCKAGES
ALONG THE BLACK RIVER FROM AROUND THE NEILLSVILLE AREA DOWN TO THE
UPPER PORTION OF LAKE ARBUTUS NEAR HATFIELD. REPORTS INDICATE THAT
THERE ARE LARGE BLOCKS OF ICE MOVING DOWN THE RIVER...AND THEY ARE
OCCASIONALLY GETTING HUNG UP ON RIVER BENDS AND WHERE ROCKS CAUSE
CONSTRICTIONS IN THE RIVER.
AT THIS POINT...IT DOES NOT APPEAR THERE IS A LARGE RISK FOR
FLOODING DUE TO ICE JAMS. BUT THERE IS A RISK FOR RAPID WITHIN-BANK
RISES ALONG THE BLACK RIVER DUE TO THIS ICE ACTION. WE HAVE ALREADY
SEEN SOME RISES ON THE RIVER MONITORING GAUGES IN THAT AREA.
THERE IS STILL SOME SNOW COVER OVER THE HEADWATER OF THE BLACK RIVER
BASIN...FROM WITHEE UP TO MEDFORD. WITH THE WARM TEMPERATURES
EXPECTED THIS WEEK...THAT SNOW IS EXPECTED TO MELT AND RUNOFF
QUICKLY INTO THE RIVER. THE ICE THAT REMAINS IN THE RIVER IS
EXPECTED TO BREAK UP AND MOVE DOWNSTREAM...SO WATER LEVELS WILL NEED
TO BE MONITORED THIS WEEK AS THAT COMBINATION WILL LEAD TO HIGHER
WATER ALONG THE BLACK RIVER THIS WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
303 PM CDT MON MAR 12 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
CLIMATE...AJ
HYDROLOGY...MW
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
745 AM EDT TUE MAR 13 2012
.PREV DISCUSSION... /ISSUED 716 AM EDT TUE MAR 13 2012/
UPDATE...
SENDING A QUICK UPDATE MAINLY TO INCREASE POPS ACROSS THE AREA.
SHOWERS HAVE INCREASED IN COVERAGE...WITH ISOLATED LIGHTNING
STRIKES...SO HAVE UPDATED THE WX GRIDS TO INCLUDE THUNDER
BEGINNING IMMEDIATELY...THOUGH HAVE LIMITED THUNDER TO SLIGHT
CHANCE. HRRR HAS A GOOD HANDLE ON PRECIPITATION AND HAS THE
SHOWERS PUSHING THROUGH THE CWA THROUGH THE MORNING HOURS. IT ALSO
DOES NOT REALLY DEVELOP ANY ADDITIONAL ACTIVITY THIS AFTERNOON SO
TRENDS WILL HAVE TO BE MONITORED IN CASE POPS NEED TO BE LOWERED
ACROSS NORTH GEORGIA EARLIER.
TDP
PREV DISCUSSION... /ISSUED 318 AM EDT TUE MAR 13 2012/
SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE OVER THE WESTERN ATLANTIC CONTINUES TO RIDGE INTO
THE SOUTHEAST. MEANWHILE THE REMNANTS OF A FRONT...ASSOCIATED
WITH THE MIDLEVEL LOW THAT PUSHED THROUGH THE CENTER OF THE
COUNTRY...CONTINUES TO APPROACH THE AREA. MOIST SOUTHERLY FLOW
AROUND THE WESTERN PERIPHERY OF THE HIGH WILL ALLOW INSTABILITY TO
CLIMB SIGNIFICANTLY TODAY...WITH MLCAPE VALUES EXCEEDING 1000 J/KG
IN SOME AREAS. LIMITING FACTOR FOR STORM DEVELOPMENT WILL BE THE
AMOUNT OF DEEP MOISTURE AVAILABLE...THUS POPS TODAY REMAIN IN THE
SLIGHT CHANCE TO CHANCE CATEGORY. VERY LITTLE SHEAR TO SPEAK OF
AND THUS DESPITE THE INCREASING INSTABILITY...DO NOT EXPECT SEVERE
STORMS.
TEMPERATURES TODAY WILL AGAIN BE ON THE INCREASE...WITH HIGH TEMPS
PROGGED IN THE 70S JUST ABOUT EVERYWHERE. HAVE GENERALLY SIDED
WITH THE WARMER MET/GFS TEMPS AS IT IS IN BETTER AGREEMENT WITH
ECMWF.
THE FRONT MOVES THROUGH THE AREA LATE TONIGHT INTO EARLY
WEDNESDAY...BUT IN THE END IT IS HARDLY ANYTHING MORE THAN A
BRIEF WIND SHIFT AS ALL DYNAMICS REMAIN TO THE NORTH. TEMPERATURES
WILL REMAIN VERY WARM...CLIMBING INTO THE 80S IN MANY AREAS /STILL
BELOW RECORD HIGHS/. THE FRONT WILL DO LITTLE TO SENSIBLE WEATHER
EXCEPT TO PUSH THE BETTER MOISTURE SOUTH...AND THUS HAVE TRENDED
POPS DOWN FOR WEDNESDAY AFTERNOON WITH ONLY SLIGHT CHANCE
REMAINING SOUTH AND NO POPS FOR WEDNESDAY NIGHT. THIS IS SHORT-
LIVED...HOWEVER...AS RIDGING BUILDING IN ALOFT AND CONTINUED
SOUTHERLY FLOW WILL BRING MOISTURE BACK TO THE REGION FOR THE
EXTENDED.
TDP
LONG TERM /THURSDAY THROUGH MONDAY/...
ECMWF AND GFS KEEP A PROGRESSIVE FLOW OVER THE CWA AT THE EARLY PART
OF THE LONG TERM...BUT THEN BUILDS A LARGE H5 RIDGE OVER THE EASTERN
U.S. DURING THE WEEKEND WHICH WILL HOLD INTO THE EARLY PART OF NEXT
WEEK. FOR THURSDAY AND FRIDAY...A SERIES OF SHORT WAVES WILL MOVE
THROUGH THE FLOW KEEPING THE RISK OF SHOWERS/THUNDERSTORMS OVER THE
CWA. MODELS BEGIN DIFFERING ON THE SOLUTION FOR THE WEEKEND. GFS
DOESNT CLEAR OUT THE MOISTURE COMPLETELY AND THIS WOULD KEEP THE
RISK OF SHOWERS/THUNDERSTORMS IN THE FORECAST THROUGH THE WEEKEND.
THE ECMWF BUILDS A RIDGE OF HIGH PRESSURE AT THE SURFACE WHICH NOSES
INTO THE CWA. THIS BRINGS MORE STABLE AND SLIGHTLY COOLER AIR INTO
THE CWA...BUT CONTINUES TO HOLD ON TO MOISTURE. THE END RESULT OF
BOTH MODELS IS THERE IS ENOUGH MOISTURE TO KEEP THE RISK OF AT LEAST
SHOWERS IN THE LONG TERM FOR THE WEEKEND AND INTO EARLY NEXT WEEK.
MEX GUIDANCE IS INDICATING RECORD OR NEAR RECORD HIGH TEMPS FOR
THURSDAY AND FRIDAY WITH A SLIGHT COOL DOWN FOR THE WEEKEND AND INTO
EARLY NEXT WEEK AS THE SURFACE FLOW BECOMES EAST TO NORTHEAST. THIS
IS THE SECOND NIGHT IN A ROW THAT THE MODELS ARE GOING FOR
RECORD/NEAR RECORD TEMPS AND SEE NO REASON TO GO AGAINST THIS AT
THIS TIME.
17
&&
.AVIATION...
12Z UPDATE...
IFR TO LIFR CIGS HAVE DEVELOPED ACROSS THE NORTHERN TAFS THIS
MORNING WITH -SHRA AND MVFR VSBY AS WELL. MCN AND CSG STILL VFR
ON CIGS AND HOVERING MVFR ON VSBY. SHOULD SEE GRADUAL IMPROVEMENT
THROUGH THE MORNING BUT EXPECT MAINLY IFR CONDITIONS TO REMAIN
THROUGH 18Z...THEN LIFTING TO MVFR AND VFR BY 00Z. ALL GUIDANCE
INDICATING VLIFR CONDITIONS TOMORROW WITH RADIATIONAL FOG
DEVELOPING. HAVE INCLUDED 1SM FEW001...LATER FORECASTS WILL WORK
OUT THE DETAILS. THUNDER IS POSSIBLE AT ANY TIME TODAY BUT
EXPECTING MOSTLY -SHRA SO HAVE NOT INCLUDED TSRA IN TAFS AT THIS
TIME. SOUTHWEST WINDS THROUGH THE PERIOD...GENERALLY BELOW 5KT
EXCEPT BRIEFLY HIGHER THIS AFTERNOON.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON WINDS.
MEDIUM ON CIGS/VSBY THIS MORNING...MEDIUM-HIGH ON CIGS/VSBY
WEDNESDAY MORNING.
MEDIUM ON OCCURRENCE OF THUNDER...LOW ON POTENTIAL IMPACTS TO ATL.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 75 53 83 52 / 80 10 10 5
ATLANTA 74 57 81 59 / 90 10 10 5
BLAIRSVILLE 71 51 76 49 / 60 10 10 5
CARTERSVILLE 76 50 80 49 / 90 10 10 10
COLUMBUS 75 56 83 56 / 90 10 20 5
GAINESVILLE 72 54 80 56 / 90 10 10 5
MACON 76 54 83 50 / 70 10 20 5
ROME 77 51 81 50 / 70 10 10 10
PEACHTREE CITY 75 50 80 46 / 90 10 10 5
VIDALIA 78 59 84 58 / 30 10 20 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TDP
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
716 AM EDT TUE MAR 13 2012
.UPDATE...
SENDING A QUICK UPDATE MAINLY TO INCREASE POPS ACROSS THE AREA.
SHOWERS HAVE INCREASED IN COVERAGE...WITH ISOLATED LIGHTNING
STRIKES...SO HAVE UPDATED THE WX GRIDS TO INCLUDE THUNDER
BEGINNING IMMEDIATELY...THOUGH HAVE LIMITED THUNDER TO SLIGHT
CHANCE. HRRR HAS A GOOD HANDLE ON PRECIPITATION AND HAS THE
SHOWERS PUSHING THROUGH THE CWA THROUGH THE MORNING HOURS. IT ALSO
DOES NOT REALLY DEVELOP ANY ADDITIONAL ACTIVITY THIS AFTERNOON SO
TRENDS WILL HAVE TO BE MONITORED IN CASE POPS NEED TO BE LOWERED
ACROSS NORTH GEORGIA EARLIER.
TDP
&&
.PREV DISCUSSION... /ISSUED 318 AM EDT TUE MAR 13 2012/
SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE OVER THE WESTERN ATLANTIC CONTINUES TO RIDGE INTO
THE SOUTHEAST. MEANWHILE THE REMNANTS OF A FRONT...ASSOCIATED
WITH THE MIDLEVEL LOW THAT PUSHED THROUGH THE CENTER OF THE
COUNTRY...CONTINUES TO APPROACH THE AREA. MOIST SOUTHERLY FLOW
AROUND THE WESTERN PERIPHERY OF THE HIGH WILL ALLOW INSTABILITY TO
CLIMB SIGNIFICANTLY TODAY...WITH MLCAPE VALUES EXCEEDING 1000 J/KG
IN SOME AREAS. LIMITING FACTOR FOR STORM DEVELOPMENT WILL BE THE
AMOUNT OF DEEP MOISTURE AVAILABLE...THUS POPS TODAY REMAIN IN THE
SLIGHT CHANCE TO CHANCE CATEGORY. VERY LITTLE SHEAR TO SPEAK OF
AND THUS DESPITE THE INCREASING INSTABILITY...DO NOT EXPECT SEVERE
STORMS.
TEMPERATURES TODAY WILL AGAIN BE ON THE INCREASE...WITH HIGH TEMPS
PROGGED IN THE 70S JUST ABOUT EVERYWHERE. HAVE GENERALLY SIDED
WITH THE WARMER MET/GFS TEMPS AS IT IS IN BETTER AGREEMENT WITH
ECMWF.
THE FRONT MOVES THROUGH THE AREA LATE TONIGHT INTO EARLY
WEDNESDAY...BUT IN THE END IT IS HARDLY ANYTHING MORE THAN A
BRIEF WIND SHIFT AS ALL DYNAMICS REMAIN TO THE NORTH. TEMPERATURES
WILL REMAIN VERY WARM...CLIMBING INTO THE 80S IN MANY AREAS /STILL
BELOW RECORD HIGHS/. THE FRONT WILL DO LITTLE TO SENSIBLE WEATHER
EXCEPT TO PUSH THE BETTER MOISTURE SOUTH...AND THUS HAVE TRENDED
POPS DOWN FOR WEDNESDAY AFTERNOON WITH ONLY SLIGHT CHANCE
REMAINING SOUTH AND NO POPS FOR WEDNESDAY NIGHT. THIS IS SHORT-
LIVED...HOWEVER...AS RIDGING BUILDING IN ALOFT AND CONTINUED
SOUTHERLY FLOW WILL BRING MOISTURE BACK TO THE REGION FOR THE
EXTENDED.
TDP
LONG TERM /THURSDAY THROUGH MONDAY/...
ECMWF AND GFS KEEP A PROGRESSIVE FLOW OVER THE CWA AT THE EARLY PART
OF THE LONG TERM...BUT THEN BUILDS A LARGE H5 RIDGE OVER THE EASTERN
U.S. DURING THE WEEKEND WHICH WILL HOLD INTO THE EARLY PART OF NEXT
WEEK. FOR THURSDAY AND FRIDAY...A SERIES OF SHORT WAVES WILL MOVE
THROUGH THE FLOW KEEPING THE RISK OF SHOWERS/THUNDERSTORMS OVER THE
CWA. MODELS BEGIN DIFFERING ON THE SOLUTION FOR THE WEEKEND. GFS
DOESNT CLEAR OUT THE MOISTURE COMPLETELY AND THIS WOULD KEEP THE
RISK OF SHOWERS/THUNDERSTORMS IN THE FORECAST THROUGH THE WEEKEND.
THE ECMWF BUILDS A RIDGE OF HIGH PRESSURE AT THE SURFACE WHICH NOSES
INTO THE CWA. THIS BRINGS MORE STABLE AND SLIGHTLY COOLER AIR INTO
THE CWA...BUT CONTINUES TO HOLD ON TO MOISTURE. THE END RESULT OF
BOTH MODELS IS THERE IS ENOUGH MOISTURE TO KEEP THE RISK OF AT LEAST
SHOWERS IN THE LONG TERM FOR THE WEEKEND AND INTO EARLY NEXT WEEK.
MEX GUIDANCE IS INDICATING RECORD OR NEAR RECORD HIGH TEMPS FOR
THURSDAY AND FRIDAY WITH A SLIGHT COOL DOWN FOR THE WEEKEND AND INTO
EARLY NEXT WEEK AS THE SURFACE FLOW BECOMES EAST TO NORTHEAST. THIS
IS THE SECOND NIGHT IN A ROW THAT THE MODELS ARE GOING FOR
RECORD/NEAR RECORD TEMPS AND SEE NO REASON TO GO AGAINST THIS AT
THIS TIME.
17
AVIATION...
06Z UPDATE...
MAINLY VFR CONDITIONS ACROSS THE AREA AT AFD/TAF TIME...WITH SOME
MVFR AND IFR VSBYS IN AREAS OF PATCHY FOG. GUIDANCE HAS NOT
HANDLED TRENDS WELL...FORECASTING MUCH LOWER CONDITIONS THAN
OBSERVED. OVERALL THOUGH EXPECT A LOWERING TREND TO CONTINUE WITH
IFR CIGS DEVELOPING NEAR 12Z. SE WINDS SHIFT SW NEAR 12Z AS WELL.
CIGS WILL LIFT THIS AFTERNOON BUT SHOULD REMAIN MVFR THROUGH 00Z
OR SO. THERE IS A CHANCE OF THUNDER THIS AFTERNOON BUT CONFIDENCE
IS LOW ON WHERE STORMS WILL DEVELOP. WILL CONTINUE PROB30 GROUP
FOR ALL TAFS FOR NOW. GUIDANCE HINTING AT LIFR FOG DEVELOPING
WEDNESDAY MORNING BUT HAVE ONLY INTRODUCED MVFR VSBY AT THIS TIME.
//ATL CONFIDENCE...
06Z UPDATE...
HIGH ON WINDS.
MEDIUM ON VSBY.
MEDIUM ON OCCURRENCE OF CONVECTION 18-00Z...LOW ON POTENTIAL
IMPACTS TO ATL.
MEDIUM-LOW ON CIGS...ESPECIALLY POTENTIAL DEVELOPMENT AND TIMING
OF IFR CONDITIONS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 75 53 83 52 / 80 10 10 5
ATLANTA 74 57 81 59 / 90 10 10 5
BLAIRSVILLE 71 51 76 49 / 60 10 10 5
CARTERSVILLE 76 50 80 49 / 90 10 10 10
COLUMBUS 75 56 83 56 / 90 10 20 5
GAINESVILLE 72 54 80 56 / 90 10 10 5
MACON 76 54 83 50 / 70 10 20 5
ROME 77 51 81 50 / 70 10 10 10
PEACHTREE CITY 75 50 80 46 / 90 10 10 5
VIDALIA 78 59 84 58 / 30 10 20 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
25
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1131 AM EDT TUE MAR 13 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE AREA LATER LATER THIS
AFTERNOON AND EVENING...BRINGING WITH IT A CHANCE OF SHOWERS OR
ISOLATED THUNDERSTORMS. AN UPPER LEVEL RIDGE WILL BUILD INTO THE
AREA WEDNESDAY THROUGH THE REMAINDER OF THE WORK WEEK...RESULTING IN
ABOVE NORMAL TEMPERATURES THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM TUESDAY...
OVERVIEW:
IN THE UPPER LEVELS...WESTERLY FLOW ALOFT WILL PREVAIL THROUGH
TONIGHT OVER THE CAROLINAS AND MID-ATLANTIC. AN UPPER LEVEL
DISTURBANCE THAT EMANATED FROM CONVECTION ALONG THE CENTRAL GULF
COAST YESTERDAY MORNING AND THAT PROGRESSED THROUGH CENTRAL NC
OVERNIGHT WAS LOCATED IN THE EASTERN CAROLINAS THIS MORNING...AND
WILL PROGRESS OFFSHORE BY NOON. AN H3 SHORTWAVE WAS NOTED IN CENTRAL
TN AT 15Z THIS MORNING...WITH ADDITIONAL SHORTWAVE ENERGY SLIGHTLY
UPSTREAM OVER ARKANSAS AND NORTHERN MS. THE LATEST RUC INDICATES THE
CENTRAL TN SHORTWAVE WILL PROGRESS INTO THE WEST/NW PIEDMONT BETWEEN
18-21Z...AND THE AR/MS SHORTWAVE WILL PROGRESS THROUGH NORTHERN
AL/GA INTO UPSTATE SC BY 21Z. THESE FEATURES ARE PROGGED TO INTERACT
TO SOME DEGREE...PROGRESSING THROUGH CENTRAL NC TO THE COAST BY OR
SHORTLY AFTER 00-03Z THIS EVENING. IN THE LOWER LEVELS...THE
OFFSHORE RIDGE WILL CONTINUE TO WEAKEN...WITH H85 FLOW VEERING FROM
SOUTHWESTERLY TO WESTERLY BY 00Z...THEN NORTHWEST OVERNIGHT AS A
WEAK H85 TROUGH PROGRESSES THROUGH THE MID-ATLANTIC/CAROLINAS.
TODAY:
SHOWER ACTIVITY PROGRESSING EASTWARD THROUGH THE AREA AT ~25 MPH
THIS MORNING IS LIKELY BEING FORCED BY THE UPPER LEVEL DISTURBANCE
THAT PUSHED INTO THE AREA FROM THE SOUTHWEST LAST NIGHT AND WHICH IS
CURRENTLY PROGRESSING INTO EASTERN NC. SHOWER ACTIVITY SHOULD
CONTINUE TO WANE AS THE AFOREMENTIONED DISTURBANCE TRACKS EAST AWAY
FROM CENTRAL NC...AND WILL INDICATE PRECIP CHANCES LOWERING AND
ENDING FROM WEST-EAST THROUGH 16-18Z. POCKETS OF SUNSHINE WERE NOTED
ON VIS SAT IMAGERY IN THE WAKE OF SHOWER ACTIVITY WEST OF HWY 1 AT
15Z...ALTHOUGH LOW STRATUS (CEILINGS ~1000-1500 FT AGL) HAS RECENTLY
DEVELOPED/EXPANDED UPSTREAM ALONG THE I-77 CORRIDOR AND MAY HELP
LIMIT HEATING THROUGH NOON IN THE WESTERN PIEDMONT BEFORE
STRENGTHENING INSOLATION/MIXING HELP SCATTER IT OUT TO SOME DEGREE.
AT THE VERY LEAST EXPECT POCKETS OF HEATING ACROSS THE AREA THIS
AFTERNOON...MORE-SO IN THE WESTERN PIEDMONT ASSUMING THE
AFOREMENTIONED STRATUS DOES NOT LINGER LONGER THAN EXPECTED.
W/REGARD TO INSTABILITY...SFC DEWPOINTS (MID/UPPER 50S) SHOULD BE
RELATIVELY UNIFORM ACROSS THE AREA THIS AFTERNOON...ALTHOUGH TEMPS
ARE EXPECTED TO BE A FEW DEGREES WARMER AND MID-LEVEL LAPSE RATES
ARE PROGGED TO BE ~1C STEEPER IN W/NW PORTIONS OF THE AREA. AS A
RESULT...THE RELATIVE BEST INSTABILITY THIS AFTERNOON SHOULD BE IN
THE WEST/NW PIEDMONT...WHERE 500-1000 J/KG OF MLCAPE COULD BE
PRESENT. FURTHER EAST...MLCAPE VALUES MAY BE LIMITED TO ~500 J/KG.
W/REGARD TO FORCING...THE SHORTWAVE PROGRESSING INTO EASTERN TN AND
THE OTHER SHORTWAVE PROGRESSING INTO NORTHERN AL AT 15Z THIS MORNING
WILL PROGRESS INTO THE CAROLINAS THIS AFTERNOON. ALTHOUGH LOWER
LEVEL FORCING WILL BE LARGELY ABSENT TODAY...THE AFOREMENTIONED
UPPER WAVES SHOULD PROVIDE SUFFICIENT ASCENT FOR AT LEAST ISOLD
CONVECTION TO DEVELOP IN THE PRESENCE OF MARGINAL INSTABILITY AND
FAVORABLE DIURNAL TIMING. THE 00/06Z HIGH-RES WRF/NMM MODELS DO NOT
ADD MUCH CONFIDENCE TO THE CONVECTIVE FCST...SHOWING A VARIETY OF
SOLUTIONS THAT DIFFER BOTH IN COVERAGE AND IN TIME. WITH THE ABOVE
IN MIND...WILL KEEP THE PRECIP FORECAST AS IS...INDICATING A 30%
CHANCE OF SHOWERS/STORMS THROUGH 00Z...THOUGH IT IS POSSIBLE ISOLD
CONVECTION (SHOULD IT DEVELOP) COULD PERSIST INTO THE 00-03Z TIME
FRAME EAST OF HWY 1. GIVEN RELATIVELY HOMOGENEOUS THICKNESSES ACROSS
THE AREA...HIGHS WILL BE DICTATED PRIMARILY BY CLOUD COVER. EXPECT
HIGHS RANGING FROM THE MID 70S (~75F) WEST OF HWY 1 TO LOWER 70S
EAST OF I-95.
SEVERE THREAT:
0-6KM BULK SHEAR VALUES TODAY ARE PROGGED TO BE 20-25 KT OR LESS. AS
A RESULT...EVEN IF CONVECTION DEVELOPS THIS AFTERNOON...BULK SHEAR
VALUES WILL ONLY BE MARGINALLY SUPPORTIVE OF MULTICELLULAR
ORGANIZATION. ADDITIONALLY...THE MIXED LAYER SHOULD BE RELATIVELY
SHALLOW TODAY...WITH LITTLE DCAPE/EVAP COOLING POTENTIAL...NOT TO
MENTION LOW/MID LEVEL FLOW (SFC-10 KFT) WILL BE NO MORE THAN 15-25
KT. WITH THE ABOVE IN MIND...DO NOT ANTICIPATE ANY SEVERE THREAT.
TONIGHT:
A MUCH DRIER MID/UPPER LEVEL AIRMASS WILL ADVECT INTO THE AREA VIA
WESTERLY FLOW ALOFT AFTER 00Z THIS EVENING...AND THIS SHOULD ALLOW
FOR A FAIR AMOUNT OF CLEARING FROM WEST-EAST BETWEEN 00-06Z. GIVEN
EXPECTED CLEARING AND THE PRESENCE OF A WEAK/BAGGY MSLP GRADIENT...
RADIATIONAL COOLING SHOULD ALLOW A NOCTURNAL INVERSION TO DEVELOP
WITHIN A FEW HRS AFTER SUNSET. DESPITE ADDITIONAL H3 SHORTWAVE
ENERGY EXPECTED TO DIG INTO THE AREA FROM THE N/NW OVERNIGHT...THE
COMBINATION OF DRY MID/UPPER LEVELS AND NOCTURNAL STABILIZATION WILL
PRECLUDE THE POTENTIAL FOR ANY PRECIPITATION. GIVEN NO REAL AIRMASS
CHANGE (STAGNANT GRADIENT)...EXPECT LOWS SIMILAR TO LAST NIGHT...IN
THE LOWER/MID 50S...WARMEST EAST/SE. GIVEN CALM WINDS AND RESIDUAL
BOUNDARY LAYER MOISTURE...AS LONG AS SKIES CLEAR AS EXPECTED...
WIDESPREAD FOG IS A GOOD BET TONIGHT. AREAS OF DENSE FOG OR EVEN
WIDESPREAD DENSE FOG WILL BE POSSIBLE...AND A DENSE FOG ADVISORY MAY
BE NEEDED LATE TONIGHT/WED MORNING. -VINCENT
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...
THE UPPER LEVEL RIDGE WILL BEGIN TO AMPLIFY WEDNESDAY WHILE THE
850MB HIGH BEGINS TO STRENGTHEN OVER THE SOUTHEAST US. DRY
ADIABATIC MIXING TO 850MB...WHICH SEEMS POSSIBLE WITH THE 850MB HIGH
STILL TO THE SOUTHWEST AND NORTHWESTERLY FLOW OVER THE CWA...YIELDS
HIGHS IN THE LOWER 80S. STATISTICAL GUIDANCE HAS BEEN INCHING IN
THIS DIRECTION ALSO...SO THERE IS FAIRLY GOOD CONFIDENCE THAT MOST
LOCATIONS WILL REACH 80 DEGREES. WILL FORECAST 79-82 WITH WARMEST
READINGS IN THE SOUTHEAST. -BLS
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT: CONTINUED DRY AND VERY
WARM. THE MID LEVEL LOW OVER SOUTHERN QUEBEC WEDNESDAY EVENING
CROSSES NEW ENGLAND AND MOVES TO JUST OFF THE CANADIAN MARITIMES BY
THURSDAY NIGHT. AS THIS LOW AND ASSOCIATED MID LEVEL TROUGH MOVE TO
OUR NORTHEAST... A MID LEVEL RIDGE AXIS SHIFTS EASTWARD OVER NC
WEDNESDAY NIGHT/THURSDAY... ENSURING CONTINUED DRY AND SINKING AIR
IN THE MID-UPPER LEVELS. THE SURFACE BACKDOOR FRONT ASSOCIATED WITH
THIS NEW ENGLAND LOW IS EXPECTED TO MOVE NO FURTHER SOUTHEAST THAN
NORTHEAST VA... WHICH WILL KEEP NC WITHIN A LIGHT/VARIABLE SURFACE
REGIME BECOMING SOUTHERLY THURSDAY. AFTER POCKETS OF DAYBREAK FOG
THURSDAY MORNING THAT SHOULD EASILY MIX OUT BY MID MORNING... THE
WEAK WARM AIR ADVECTION AND LACK OF CLOUDS ALOFT WILL ALLOW FOR
STRONG HEATING AS THICKNESSES REMAIN (AS MODELS HAVE INDICATED FOR
SEVERAL DAYS NOW) 40-50 METERS ABOVE NORMAL. LOWS 50-55 AND HIGHS
78-82. THE MID LEVEL RIDGE AXIS DROPS TO OUR SOUTHEAST THURSDAY
NIGHT AS A WEAK SOUTHERN STREAM WAVE MOVES ACROSS KY AND THE OH
VALLEY TOWARD THE CENTRAL/SRN APPALACHIANS. SLOWLY INCREASING
925-850 MB WINDS FROM WEST TO EAST ACROSS WV/VA WILL HELP SHARPEN
THE LEE TROUGH OVERNIGHT... AND THIS INCREASING LOW LEVEL MASS
CONVERGENCE AND APPROACH OF THE MID LEVEL WAVE WILL LEAD TO SKIES
BECOMING PARTLY TO MOSTLY CLOUDY WEST TO EAST. LOWS THURSDAY NIGHT
54-58 WITH ANOTHER ROUND OF PATCHY GROUND FOG POSSIBLE TOWARD DAWN.
-GIH
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 310 AM TUESDAY...
FOR FRIDAY THROUGH SATURDAY NIGHT: MOSTLY CLOUDY AND WARM WITH AN
IMPROVING CHANCE OF SHOWERS. AS THE AFOREMENTIONED WAVE CROSSES THE
CENTRAL/SRN APPALACHIANS FRIDAY MORNING... A NORTHERN STREAM WAVE IS
EXPECTED TO CROSS SRN ONTARIO INTO SRN QUEBEC AND EVENTUALLY
ATTEMPTS TO MERGE WITH THE SOUTHERN STREAM WAVE... CULMINATING IN A
WEAK BUT EXPANSIVE TROUGH FROM THE CANADIAN MARITIMES ALONG THE EAST
COAST BY EARLY SATURDAY... ACCOMPANIED BY A BACKDOOR SURFACE FRONT
MOVING SOUTHWARD THROUGH THE NORTHEAST AND MIDATLANTIC REGION. THE
ECMWF DEPARTS FROM THE GFS HERE WITH A FASTER NORTHERN STREAM WAVE
WHICH DIGS MORE STRONGLY TO THE SOUTHWEST OVER OH AND RESULTS IN
MUCH MORE PRECIP AS ITS CLOSED LOW DROPS THROUGH WV/VA/NRN NC
THROUGH SATURDAY NIGHT. WHILE THE ECMWF HAS FAVORED A STRONGER
SYSTEM OFF THE NORTHEAST/MIDATLANTIC FOR ITS LAST FEW RUNS... THIS
DOESN`T AGREE WITH ITS ENS MEAN... AND THE GFS HAS BEEN MORE
CONSISTENT WITH THE EVOLUTION OF THE TRAILING PORTION OF THIS MID
LEVEL TROUGH... KEEPING IT WEAKER AND JUST OFF THE COAST. FOLLOWING
THIS LATTER SOLUTION... EXPECT THE BACKDOOR FRONT TO PUSH SSE TO THE
NC/VA BORDER FRIDAY NIGHT THEN EASE SLOWLY SOUTHWARD THROUGH NC
DURING SATURDAY. REGARDING SENSIBLE WEATHER... AS MOISTURE STEADILY
INCREASES AND DEEPENS WITH THE APPROACHING MID LEVEL WAVE... EXPECT
FRIDAY MORNING SLIGHT RAIN CHANCES TO RISE TO CHANCE AND SPREAD
EASTWARD DURING FRIDAY AFTERNOON. AN ISOLATED STORM OR TWO IS
POSSIBLE... ALTHOUGH THE MOIST MID-UPPER LEVELS (PRECIP WATER RISING
TO 200-250% OF NORMAL) WILL LIMIT MID LEVEL LAPSE RATES. EXPECT THE
CHANCE OF SHOWERS TO DROP BACK DOWN WITH THE LOSS OF HEATING FRIDAY
NIGHT... BUT WITH THE HIGH MOISTURE CONTENT AND RENEWED HEATING
SATURDAY... EXPECT ANOTHER CHANCE OF SHOWERS ESPECIALLY NEAR THE
SLOW-MOVING BACKDOOR FRONTAL ZONE ACROSS THE EASTERN AND SOUTHERN
CWA SATURDAY AFTERNOON INTO THE EVENING. CONTINUED WARM DESPITE THE
CLOUDS WITH THICKNESSES HOLDING WELL ABOVE NORMAL. HIGHS BOTH DAYS
IN THE MID-UPPER 70S. LOWS 57-60 FRIDAY NIGHT AND 54-58 SATURDAY
NIGHT AS HIGH PRESSURE BEGINS TO NOSE INTO NC FROM THE NNE.
FOR SUNDAY/MONDAY: DEEP MID LEVEL LONGWAVE TROUGHING DIGS OVER THE
WEST COAST AND ROCKIES... WHICH SERVES TO BUILD UP THE RIDGE OVER
THE EASTERN U.S.... POTENTIALLY LEADING TO DEVELOPMENT OF AN OMEGA
BLOCK OVER THE GREAT LAKES AND INTERIOR NORTHEAST BY MONDAY. SURFACE
HIGH PRESSURE INITIALLY CENTERED OVER THE NEW ENGLAND COAST SLIDES
SOUTHWARD JUST OFF THE MIDATLANTIC COAST WHILE EXTENDING THROUGH NC.
HINTS WITHIN THE GFS AND ECMWF OF A LINGERING WEAK SHEAR ZONE OVER
THE CAROLINAS (SSE OF THE BLOCK) AND POTENTIAL LOW LEVEL EASTERLY
FLOW OFF THE ATLANTIC MAY LEAD TO PATCHY SHOWERS OVER NC IN THIS
TIME FRAME... BUT CONFIDENCE AT THIS RANGE IS SUFFICIENTLY LOW TO
KEEP THE FORECAST DRY. THICKNESSES DROP WITHIN THE SURFACE RIDGE BUT
REMAIN ABOVE SEASONAL NORMALS. EXPECT HIGHS CLOSE TO 70 AND LOWS IN
THE 40S. -GIH
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 730 AM TUESDAY...
PATCHES OF LIGHT RAIN ARE MOVING ACROSS CENTRAL NC THIS MORNING AS A
SERIES OF UPPER LEVEL DISTURBANCES DRIFT ACROSS THE AREA.
CEILINGS..HOWEVER..HAVE YET TO FALL BELOW 3K FT...AND OUTSIDE OF A
HEAVIER SHOWER THIS MORNING...CEILINGS SHOULD REMAIN VFR AS HEATING
AND WEAK MIXING COMMENCE. THERE IS QUITE A BIT OF UNCERTAINTY AS TO
HOW PRECIP WILL EVOLVE TODAY...AND THUS THERE IS LOW CONFIDENCE IN
TIMING AND IMPACT AT INDIVIDUAL TERMINALS. IN GENERAL.. CEILINGS
AND VSBYS SHOULD REMAIN IN THE 2500 TO 4000FT RANGE. THE LAST OF
THE AFOREMENTIONED UPPER DISTURBANCES SHOULD CROSS THE AREA BETWEEN
15Z AND 21Z...DURING WHICH TIME THERE WILL BE A CHANCE OF ANOTHER
ROUND OF SHOWERS OR AN ISOLATED THUNDERSTORM. ALL SHOWERS/STORMS
ARE EXPECTED TO BE EAST OF KFAY/KRWI BY 21Z-00Z.
SKIES WILL CLEAR TONIGHT AND WEST-NORTHWESTERLY WINDS ARE FORECAST
TO BE LIGHT. LOW LEVEL MOISTURE WILL REMAIN HIGH HOWEVER...WHICH
SHOULD LEAD TO A GOOD CHANCE OF FOG AT ALL TERMINALS. CONFIDENCE IN
FOG DEVELOPMENT IS HIGHEST AT KRDU/KRWI/KFAY...WHERE GUIDANCE SHOWS
FOG DEVELOPING JUST AFTER MIDNIGHT.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED TO PREVAIL EACH DAY...BUT A PERIOD OF
FOG/STRATUS IS POSSIBLE DURING THE MORNING HOURS. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE FRIDAY AFTERNOON INTO SATURDAY DUE
TO AN UPPER-LEVEL DISTURBANCE AND WEAK SURFACE LOW PRESSURE MOVING
THROUGH THE AREA.
&&
.CLIMATE...
HERE ARE UPCOMING HIGH TEMPERATURES RECORDS...
AT RDU:
03/14: 86 IN 1990
03/15: 87 IN 1973
03/16: 86 IN 1945
AT GSO:
03/14: 82 IN 1990
03/15: 87 IN 1967
03/16: 85 IN 1945
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
CLIMATE...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1030 AM CDT TUE MAR 13 2012
.DISCUSSION...
MADE ONLY A FEW MINOR TWEAKS TO THE GOING FORECAST AS TODAY
CONTINUES TO BE ON TRACK FOR A WARM DAY WITH BREEZY WINDS IN THE
AFTERNOON. INVERSION HAS YET TO FULLY MIX OUT SO WINDS HAVE BEEN
FAIRLY LIGHT SO FAR BUT WITH THE PRESSURE GRADIENT INCREASING THIS
AFTERNOON THEY SHOULD COME UP INTO THE 15 TO 25 KT RANGE. TEMPS
CONTINUE TO BE ON TRACK TO CLIMB INTO THE UPPER 50S AND LOW
60S...SO ONLY ADJUSTED A BIT TO FIT CURRENT HOURLY TRENDS.
INCREASED CLOUDS JUST A BIT AS CIRRUS MOVES IN FROM THE
WEST...ALTHOUGH IT WILL BE THIN AND PLENTY OF SUN SHOULD STILL GET
THROUGH.
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE. SOUTHEAST WINDS WILL PICK UP INTO
THE 15 TO 20 KT RANGE WITH GUSTS UP TO 25 KTS.
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT TUE MAR 13 2012/
SHORT TERM...
RELATIVELY QUIET PERIOD AS STRONG WAVE CRASHES PAC NORTHWEST THEN
MOVES INTO SASKATCHEWAN TONIGHT. THE RESULTANT LOW PRESSURE
GRADIENT WILL TIGHTEN UP AND MAKE IT SOMEWHAT BREEZY TODAY.
BETWEEN YESTERDAYS RAIN AND RECENT WARM TEMPERATURES SNOW PACK IS
ALL BUT GONE...SO WITH PLENTY OF SOLAR EXPECT ANOTHER WARM DAY.
MODELS IN DECENT AGREEMENT WITH WARM AIR MOVING NORTH TODAY. TODAYS
RECORD HIGH FOR GFK IS 51F AND FGF IS 55F. HAVE NEAR 60F IN GRIDS
SO EXPECT RECORDS TO FALL AGAIN. FAR IS 64 SO WILL BE CLOSE THERE.
BOUNDARY LAYER WINDS CRANK UP TO 20-25 KTS WITH 850 WINDS TO 40KTS
IN NAM AND GFS. LOWER LAYERS FAIRLY STABLE AS COOLER AIR RETREATS
AND DIRECTIONAL COMPONENT NOT OPTIMAL...SO EXPECT GUSTS TO 30 KTS
WEST OF VALLEY IN FAVORED HIGH TERRAIN. ON-LINE VERSION HRRR HAD
BEEN CONSISTENT IN GUSTS TO 35 KNOTS KABC TO KDVL...WITH LATEST
RUNS BACKING OFF. HAVE NEAR 30 KT GUSTS IN GRIDS ALONG WEST
VALLEY SO DO NOT ANTICIPATE WIND ADVISORY ATTM.
WINDS DIMINISH TONIGHT AS TROUGH REACHES DVL BASIN AROUND 06Z AND
THERMAL RIDGE MOVES INTO RRV. DRY AIR...CLEAR SKIES AND WARM AIR
ALOFT...HAVE UPPED MINS DUE TO THE WARMER AIR ALOFT KEEPING
TEMPERATURES A BIT HIGHER. WIND SHIFT PASSES AROUND SUNRISE
WEDNESDAY. WITH ONLY SLIGHT COOLING...ABOUT 4C TO 6C...EXPECT ONLY A
FEW DEGREES COOLER WEDNESDAY. THIS MAY WELL KEEP US FROM HAVING
ANOTHER RECORD WARM DAY.
SURFACE HIGH SETTLES OVER VALLEY WEDNESDAY NIGHT...WITH MAINLY
CLEAR SKIES AND CALM WINDS BY THURSDAY MORNING. DUE TO LOSS OF
SNOW...WET SOILS AND A BIT MORE CLOUD COVER KEPT MINS ABOVE 32F
MOST AREAS. COULD BE FOG THURSDAY MORN BUT WILL ASSESS THAT
POTENTIAL LATER. RETREATING HIGH AND FAIR AMOUNT OF SOLAR AGAIN
SO EXPECT ANOTHER UNSEASONALLY WARM DAY.
LONG TERM (FRIDAY-MONDAY)...ENSEMBLES AND OPERATIONAL MODELS IN
AGREEMENT WITH DEVELOPING EASTERN CONUS RIDGE AND WESTERN CONUS
TROUGH. AS THIS PATTERN DEVELOPS THERE WILL LIKELY BE A SURGE OF
MOISTURE/INSTABILITY BY SUNDAY. NEIGHBORING OFFICES DECIDED THAT A
DRY FORECAST WOULD BE BEST THROUGH SUNDAY NIGHT GIVEN NO STRONG
FORCING MECHANISM REPRESENTED BY THE MODELS. ALTHOUGH ISOLATED
THUNDER APPEARS POSSIBLE...FOLLOWED WITH THE NEIGHBORS. ON
MONDAY...GFS IS A BIT FURTHER EAST WITH OVERALL PATTERN COMPARED
WITH THE ECMWF. GFS PLACES A FRONTAL BOUNDARY THROUGH THE FA (WET)
WHILE THE ECMWF HAS UPPER RIDGING (DRY). KEPT THE THUNDER CHANCES IN
THE FORECAST FOR MONDAY. TEMPERATURES WILL CONTINUE ABOVE NORMAL.
HYDROLOGY...
WARM TEMPERATURES THE PAST FEW DAYS HAVE ALL BUT ELIMINATED THE
SNOW PACK ACROSS THE REGION. AS A RESULT MINOR RISES HAVE BEEN
SHOWING UP ON AREA RIVERS. MONDAYS RAINFALL TOTALS...BASED ON
REPORTS AND 88D ESTIMATES...WERE GENERALLY LESS THAN ONE HALF
INCH. ISOLATED AMOUNTS UP TO ONE INCH IN THE LOWER SHEYENNE AND
UPPER SNAKE BASED ON THE 88D WILL NEED TO BE VERIFIED. WITH THE
WARM TEMPERATURES FORECAST THIS WEEK ABOUT THE ONLY SNOW THAT WILL
BE LEFT SHOULD BE IN TOWNS AND SHELTERED AREAS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
951 AM EDT TUE MAR 13 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION TODAY FOLLOWED BY
SUBTROPICAL HIGH BUILDING INTO THE REGION THROUGH THE WEEKEND. THIS
WILL RESULT IN AFTERNOON CONVECTION THROUGH THE PERIOD.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM...A CHANNELED VORTMAX WAS ANALYZED ON THE WATER VAPOR
AND RUC 500MB SFC OVR CENTRAL TN...TRACKING THRU QUASI-ZONAL FLOW.
SCATTERED SHOWERS AND A COUPLE OF ISOLD TSTMS WERE BEING TRIGGERED
BY THE ASSOCIATED DPVA ACRS ERN TN/GA. THIS ACTIVITY LOOKS TO REMAIN
ISOLD AND PROBABLY ON A WEAKENING TREND AS IT ENTERS THE CWFA THIS
MORNING...AS SPC MESOANALYSIS SHOWS MUCAPES <500 J/KG IN THE
ENVIRONMENT THE CONVECTION IS MOVING. AS FOR CONVECTION THIS
AFTN...GUIDANCE STILL RATHER SUBDUED DESPITE DESTABILIZATION TO OVER
1500 J/KG AND THE VORTMAX STILL NOT THRU THE AREA BY PEAK HEATING.
ONLY THE 4 KM NCEP WRF HAS ANYTHING MORE THAN A STRAY STORM THIS
AFTN ACRS THE CWFA. BUT I AM GOING TO LEAVE THE LOW-END
CHC/SCATTERED WORDING FOR THE PIEDMONT DUE TO THE TIMING OF THE
VORTMAX FOR NOW. OTHERWISE...ONLY MINOR TWEAKS WERE MADE FOR THE
TODAY PERIOD.
PREVIOUS DISCUSSION...
AT 3 AM EDT TUESDAY...AN UPPER TROUGH AXIS WILL PROGRESS FROM THE OH
AND TN VALLEYS TO THE APPALACHIANS TODAY. A SHORTWAVE MOVING THROUGH
THIS TROUGH WILL CROSS OUR AREA AT MIDDAY. MOISTURE AHEAD OF THE
REMNANTS OF A FRONT WILL CONTINUE TO SUPPORT SHOWERS ACROSS OUR AREA
TODAY...BUT WITH LESS COVERAGE THAN BEFORE AS VEERING LOW LEVEL FLOW
LEADS TO LESS OF AN UPSLOPE COMPONENT AND WEAKER ISENTROPIC UPGLIDE.
FORECAST MAXIMUM TEMPERATURES WILL BE WELL ABOVE NORMAL TODAY IN
WARM ADVECTION...AND MODEL CAPE IS QUITE HIGH DURING PEAK HEATING...
WITH THE NAM SHOWING ALMOST 3000 J/KG IN UPSTATE SC...AND THE GFS
2000 J/KG IN NE GA. WITH MODEST SPEED AND DIRECTIONAL SHEAR...SOME
THUNDERSTORMS COULD BE STRONG. DRIER AIR ALOFT AND LOW WET BULB
ZEROS COULD SUPPORT HAIL AND GUSTY WINDS IN THE STRONGER STORMS.
BY THIS EVENING VEERING FLOW ALOFT WILL LEAD TO DRYING FROM THE
WEST...ENDING THE CHANCE OF PRECIPITATION. AFTER MIDNIGHT WINDS
SHIFT TO NW AT THE SURFACE AS THE REMNANTS OF THE FRONT MOVE BY.
MINIMUM TEMPERATURES WILL BE WELL ABOVE NORMAL AS HEIGHTS RISE WITH
THE PROGRESSION OF THE UPPER TROUGH...AND A LIGHT DOWNSLOPE FLOW
ENSUES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 230 AM EDT TUE...AN UPPER LEVEL RIDGE WILL REMAIN DOMINANT
ACROSS THE EAST THROUGH THE SHORT TERM PERIOD. ANY ISOLATED
CONVECTION UNDER THE RIDGE LATE WED AFTN SHOULD BE LIMITED TO A FEW
MTN RIDGETOP LOCATIONS WHERE UPSLOPE FLOW AND DIFFERENTIAL HEATING
CAN PROVIDE SOME WEAK TRIGGERING. THE MAIN STORY WILL BE WARM
TEMPERATURES...WITH 70S IN THE MTNS AT ALL BUT THE HIGHEST
ELEVATIONS...AND LOWER 80S ACROSS MOST OF THE FOOTHILLS AND
PIEDMONT. THIS SHOULD FALL A DEGREE OR TWO SHORT OF THE RECORDS AT
GSP/84...AND CLT/82.
MTN CONVECTIVE COVERAGE MAY BE JUST A BIT BETTER ON THU AFTN AS LOW
LEVEL CONVERGENCE IN THE WIND FIELD IMPROVES SLIGHTLY.
HOWEVER...DEEP LAYER CAPE SHOULD CONTINUE TO BE RATHER LIMITED AS
MID LEVEL TEMPS WARM FURTHER UNDER THE BUILDING RIDGE. MAX TEMPS
WILL BE COMPARABLE TO A DEGREE WARMER THAN WED. A WEAK WAVE MAY TOP
THE RIDGE THU NIGHT...BUT WITH THE MAIN MOISTURE AND FORCING PASSING
NORTH OF THE REGION THROUGH THE EARLY MORNING HOURS. WILL KEEP SCHC
TO CHC SHOWERS GOING MAINLY IN THE WRN/NRN MTNS FOR THE NIGHTTIME
PERIOD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AT 230 AM TUESDAY...BOTH THE GFS AND THE ECMWF ARE IN GOOD AGREEMENT
THROUGH THE EXTENDED FORECAST PERIOD. A BROAD UPPER LEVEL RIDGE OF
HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST...WITH A SERIES OF
SHORTWAVES ORIGINATING IN THE SOUTHERN STREAM MOVING OVER THE RIDGE
ON FRIDAY AND SATURDAY. THE UPPER RIDGING WILL AMPLIFY SIGNIFICANTLY
SUNDAY INTO EARLY NEXT WEEK.
FRIDAY AND SATURDAY...A BROAD SUBTROPICAL HIGH OVER THE SOUTHEAST
U.S. WILL SLOWLY SHIFT EAST AND HEIGHTS WILL BE LOWERED. THIS WILL
ALLOW A SERIES OF WEAK SHORTWAVES OVER THE MISSISSIPPI VALLEYS TO
MOVE NE ACROSS OUR FORECAST AREA DURING THE PERIOD. THE LATEST
FORECAST SOUNDINGS CONTINUE TO INDICATE THAT PRECIPITABLE WATER
VALUES WILL RANGE FROM 1 TO 1.20 INCHES AND LIFTED INDEX VALUES WILL
BE AS LOW AS -4. ALSO...AFTERNOON SURFACE BASED CAPE VALUES WILL BE
IN THE 700 TO 1500 J/KG RANGE OVER MUCH OF OUR CWA. A COMBINATION OF
DECENT DIURNAL INSTABILITY...UPPER DYNAMICS AND DEEP MOISTURE ALOFT
WILL SUPPORT FOR THE DEVELOPMENT OF THUNDERSTORMS. HOWEVER...THE
DEGREE OF INSTABILITY AND UPPER LEVEL SYNOPTIC SCALE FORCING REMAIN
A BIT UNCERTAIN. SO I WILL CONTINUE TO CARRY 30S AND 40S POPS IN THE
AFTERNOON/EVENING HOURS. SUNDAY AND MONDAY...RATHER DRIER CONDITIONS
ARE EXPECTED AS THE UPPER RIDGING SIGNIFICANTLY AMPLIFIES OVER THE
REGION. TEMPERATURES UNDER THE RIDGE WILL BE 1O TO 15 DEGREES ABOVE
NORMAL THROUGH THE FORECAST PERIOD.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AT KCLT...GUIDANCE CONSENSUS SUPPORTS THE DEVELOPMENT OF AN MVFR CIG
THIS MORNING THAT LASTS UNTIL MIDDAY. LIGHT SHOWERS MOVING EAST
ACROSS THE FIELD ARE NOT PRODUCING VSBY RESTRICTIONS...AND GUIDANCE
HAS VFR VSBY. CIG IMPROVE TO LOW VFR THIS AFTERNOON...WHEN HEATING
AND INSTABILITY LEND SUPPORT FOR THUNDERSTORMS. COVERAGE WILL BE TOO
SCATTERED TO CARRY THUNDER...BUT CB WILL BE CARRIED IN THE TAF. NO
CIG IS EXPECTED BY EARLY EVENING AS CLOUDS DECREASE WITH A DRYING
WEST WIND ALOFT. SW WINDS APPROACH 10 KNOTS WITH GUSTS TODAY...THEN
GO LIGHT THIS EVENING...VEERING TO NW BEFORE DAWN WEDNESDAY AS THE
REMAIN OF AN OLD FRONT MOVE THROUGH. GUIDANCE SUPPORTS MVFR VSBY
TOWARD DAWN WEDNESDAY MORNING...PERHAPS IFR...BUT CONFIDENCE IS TOO
LOW FOR IFR THIS TIME.
ELSEWHERE...A CONSENSUS OF GUIDANCE SUGGESTS MVFR CIGS WILL CONTINUE
THIS MORNING...WITH PERHAPS SOME BRIEF IFR AT KAVL AND KGSP AT
DAYBREAK. THIS AFTERNOON CIGS RISE TO LOW VFR BEFORE DISSIPATING AS
DRIER AIR MOVES IN WITH WESTERLY FLOW ALOFT. INSTABILITY WILL BE
SUFFICIENT FOR THUNDERSTORMS...HOWEVER COVERAGE WILL BE TOO
SCATTERED FOR INCLUSION IN THE TAFS. CB WILL BE CARRIED HOWEVER.
CLOUDS DECREASE THIS EVENING WITH FURTHER DRYING. LIGHT SW WINDS
WILL APPROACH 10 KNOTS TODAY...THEN BECOME LIGHT AGAIN THIS EVENING.
WINDS VEER TO NW AFTER MIDNIGHT AS THE REMAINS OF A FRONT PASS BY.
GUIDANCE SUGGEST MVFR VSBY TOWARD DAWN WEDNESDAY...PERHAPS IFR AT
KAND...BUT CONFIDENCE IS TOO LIMITED TO CARRY IFR AT THIS TIME.
OUTLOOK...ISOLD-SCT SHRA/TSRA EXPECTED EACH AFTN. EARLY MORNING CIG
AND VSBY RESTRICTIONS POSSIBLE EACH MORNING NEAR AREAS OF RECENT
RAINFALL AND IN MOUNTAIN VALLEYS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...ARK/JAT
SHORT TERM...HG
LONG TERM...JOH
AVIATION...JAT
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
544 AM CDT TUE MAR 13 2012
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE.
.SHORT TERM...TODAY THROUGH WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE MOVING EAST OVER SOUTHERN ONTARIO EARLY THIS MORNING WHILE
WEAK HIGH PRESSURE IS SHIFTING INTO THE NORTHERN MISSISSIPPI
VALLEY. LOW CLOUDS ARE IN THE PROCESS OF EXITING NE WISCONSIN...AND
ONLY HIGH CIRRUS IS PUSHING ACROSS THE DAKOTAS UPSTREAM. LOW LEVELS
ARE QUITE DRY THERE...AND THIS DRY AIRMASS WILL MOVE INTO THE REGION
TODAY. FORECAST CONCERNS ARE RELATIVELY MINIMAL FOR THIS TIME OF
THE YEAR...AND INCLUDE MIN HUMIDITIES TODAY...AND TEMPERATURES TODAY
AND TOMORROW.
TODAY...SHORTWAVE TROUGH OVER SOUTHEAST ONTARIO WILL LIFT NE...WHILE
A SHEARED WAVE OVER THE ARROWHEAD MOVES EAST OVER LAKE SUPERIOR.
DESPITE THE SHORTWAVES ALOFT PASSING NEARBY...CYCLONIC FLOW AT THE
SURFACE WILL BE ABATING...WHILE A WEAK RIDGE AXIS SHIFTS INTO THE
REGION THIS AFTERNOON. DRIER AIR OVER THE NORTHERN PLAINS WILL BE
PUSHING ACROSS THE AREA EARLY THIS MORNING...AND THE MVFR STRATUS
WILL BE EXITING NE WISCONSIN BY 09Z OR SO. A VERY DRY AIRMASS WILL
THEN BE IN PLACE FOR THE REST OF THE DAY. THOUGH MIXING MAY ONLY
REACH TO AROUND 900MB...WINDS SHOULD ALLOW FOR DRY AIR ABOVE THE
INVERSION TO CRASH TO THE SURFACE...ESPECIALLY OVER NORTHERN AND FAR
NORTHEAST WISCONSIN WHERE THE GRADIENT WILL BE THE TIGHTEST. HAVE
LOWERED DEWPOINTS TO THE MID TEENS UP NORTH...WHICH GIVES RH/S IN
THE 20-25 PCT RANGE. BOTH THE NAM AND GFS AGREE THAT 925MB TEMPS
WILL RANGE FROM 5-10C ACROSS THE AREA...WHICH CORRESPONDS THE MOST
WITH THE BCCONSRAW AND ECMWBC...THAT GIVES HIGHS RANGING FROM THE
MID 50S NORTH TO MID 60S SOUTH.
TONIGHT...RIDGING WILL BE PASSING OVERHEAD ACROSS THE REGION. WILL
SEE CLEAR TO MOSTLY CLEAR SKIES WITH LIGHT WINDS IN THE EVENING
BECOMING SOUTHEASTERLY. AXIS OF LOW LEVEL MOISTURE WILL GET DRAWN
NORTHWARD INTO CENTRAL WISCONSIN LATE. WITH LOW LEVEL TEMPS ALSO
WARMING AND NO SIGNS OF STRATUS UPSTREAM...THINK POSSIBILITIES OF
LOW STRATUS IS RELATIVELY LOW. LOWS RANGING FROM THE MID 30S
NORTH...TO THE MID 40S SOUTH.
WEDNESDAY...STRONG SHORTWAVE TROUGH WILL BE LIFTING NE OVER CENTRAL
CANADA...WHILE ITS COLD FRONT SAGS INTO NORTHWEST WISCONSIN IN THE
AFTERNOON. AHEAD OF THE FRONT...SOUTHWEST WINDS WILL ADVECT A VERY
WARM AND RELATIVELY MOIST AIRMASS INTO THE REGION. SLIGHTLY BACKED
SE WINDS WILL KEEP FAR NE WISCONSIN A LITTLE COOLER THAN THE REST OF
THE STATE...AND WILL GO WITH HIGHS IN THE UPPER 60S NORTH TO THE
MIDDLE 70S SOUTH. TEMPS MAY STRUGGLE TO GET OUT OF THE 50S ALONG
THE LAKESHORE THOUGH. WEAK CONVERGENCE ALONG THE FRONT COMBINED
WITH A LACK OF UPPER SUPPORT SHOULD KEEP THE FRONT INACTIVE TOMORROW
AFTERNOON SO NO REAL SHOWER OR THUNDER THREAT FORESEEN.
.LONG TERM...WEDNESDAY NIGHT THRU MONDAY. MAIN FORECAST CONCERN IS
HOW HIGH TO GO WITH TEMPS...AND PINNING DOWN BEST CHANCE FOR
SHOWERS/STORMS.
SW FLOW ALOFT WILL CONTINUE THROUGH THE PERIOD...WITH NO COLD AIR
IN SIGHT. TEMPS ALOFT ACTUALLY DO NOT CHANGE MUCH...WITH ONLY A
SLIGHT RISE IN HEIGHTS THIS WEEKEND AND EARLY NEXT WEEK AS THE
UPPER RIDGE BUILDS NORTH INTO ONTARIO. EXPECT 60S FOR MOST
LOCATIONS...WITH SOME 70S POSSIBLE ACROSS CENTRAL WI AND THE FOX
VALLEY NEXT WEEK. SEVERAL RECORDS ARE LIKELY TO FALL. ONLY
EXCEPTION TO THE VERY MILD AIR WILL BE ALONG THE LAKESHORE...AS A
SE SURFACE FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS IN THE UPPER
40S AND 50S THROUGH MOST OF THE PERIOD.
FIRST CHANCE FOR SHOWERS/ISO STORMS WILL BE WEDNESDAY NIGHT AS A
WEAK FRONTAL BOUNDARY CROSSES THE AREA. NOT MANY POSITIVES TO GET
SHOWER/STORM ACTIVITY GOING...AS SURFACE CONVERGENCE IS WEAK AND
VERY LITTLE IF ANY UPPER LEVEL SUPPORT...PLUS BETTER MOISTURE
FORECAST TO BE JUST SOUTH/WEST OF THE AREA. THERE WILL BE FAIRLY
STEEP MID-LEVEL LAPSE RATES...ESPECIALLY ACROSS EASTERN WI...SO
WILL CONTINUE WITH HIGHER POPS THERE...BUT KEPT THE CHANCES LOW.
PREVIOUS ECMWF SHOWED A SHORTWAVE OVER THE NORTHERN PLAINS
THURSDAY...AND TOOK THIS FEATURE OVER LAKE SUPERIOR THURSDAY
NIGHT. THIS WOULD HAVE BROUGHT A DECENT CHANCE FOR PRECIP ACROSS
THE NORTH...HOWEVER LATEST RUN AS WELL AS OTHER MODELS AND
ENSEMBLES HAVE RIDGING AND WITH NOT MUCH UPPER SUPPORT OR
MOISTURE...WILL LEAVE THURSDAY NIGHT DRY. IF THIS SHORTWAVE
MATERIALIZES AND SLOWS A LITTLE...PASSING OVER THE AREA ON
FRIDAY...WE COULD GET SOME ACTIVITY TO DEVELOP...BUT THINK THIS IS
UNLIKELY WITH THIS PATTERN. AS WE WORK INTO THIS WEEKEND AND
EARLY NEXT WEEK...TIMING BEST CHANCES FOR SHOWERS/STORMS WILL BE
DIFFICULT AS SYNOPTIC PATTERN DOES NOT SUPPORT PRECIP. MODELS SHOW
POTENTIAL FOR WEAK SHORTWAVES MOVING THROUGH THE PLAINS AND GREAT
LAKES IN THE SW FLOW ALOFT...WHICH WOULD BRING A CHANCE OF
SHOWERS/STORMS. AFTER COORDINATION WITH SURROUNDING OFFICES...WENT
DRY FRIDAY-TUESDAY AS NO PERIOD LOOKS MORE LIKELY THAN THE OTHER
FOR SMALL CHANCE POPS AND UPPER RIDGE BUILDS OVERHEAD. BETTER
CHANCE FOR WIDESPREAD ACTIVITY LOOKS TO ARRIVE MID TO LATE NEXT
WEEK AS CLOSED UPPER LOW EJECTS OUT INTO THE PLAINS.
&&
.AVIATION...MVFR STRATUS IS DEPARTING EASTERN WISCONSIN THIS
MORNING...WHICH SHOULD SET UP VFR CONDITIONS FOR THE REST OF THE TAF
PERIOD. MAY INCLUDE LLWS AT RHI THROUGH MID-MORNING BEFORE WINDS
JUST OFF THE DECK SUBSIDE. OTHERWISE...CLEAR CONDITIONS AS WEAK
HIGH PRESSURE MOVES ACROSS THE REGION.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
214 PM EDT TUE MAR 13 2012
.PREV DISCUSSION... /ISSUED 745 AM EDT TUE MAR 13 2012/
UPDATE...
SENDING A QUICK UPDATE MAINLY TO INCREASE POPS ACROSS THE AREA.
SHOWERS HAVE INCREASED IN COVERAGE...WITH ISOLATED LIGHTNING
STRIKES...SO HAVE UPDATED THE WX GRIDS TO INCLUDE THUNDER
BEGINNING IMMEDIATELY...THOUGH HAVE LIMITED THUNDER TO SLIGHT
CHANCE. HRRR HAS A GOOD HANDLE ON PRECIPITATION AND HAS THE
SHOWERS PUSHING THROUGH THE CWA THROUGH THE MORNING HOURS. IT ALSO
DOES NOT REALLY DEVELOP ANY ADDITIONAL ACTIVITY THIS AFTERNOON SO
TRENDS WILL HAVE TO BE MONITORED IN CASE POPS NEED TO BE LOWERED
ACROSS NORTH GEORGIA EARLIER.
TDP
PREV DISCUSSION... /ISSUED 318 AM EDT TUE MAR 13 2012/
SHORT TERM /TODAY THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE OVER THE WESTERN ATLANTIC CONTINUES TO RIDGE INTO
THE SOUTHEAST. MEANWHILE THE REMNANTS OF A FRONT...ASSOCIATED
WITH THE MIDLEVEL LOW THAT PUSHED THROUGH THE CENTER OF THE
COUNTRY...CONTINUES TO APPROACH THE AREA. MOIST SOUTHERLY FLOW
AROUND THE WESTERN PERIPHERY OF THE HIGH WILL ALLOW INSTABILITY TO
CLIMB SIGNIFICANTLY TODAY...WITH MLCAPE VALUES EXCEEDING 1000 J/KG
IN SOME AREAS. LIMITING FACTOR FOR STORM DEVELOPMENT WILL BE THE
AMOUNT OF DEEP MOISTURE AVAILABLE...THUS POPS TODAY REMAIN IN THE
SLIGHT CHANCE TO CHANCE CATEGORY. VERY LITTLE SHEAR TO SPEAK OF
AND THUS DESPITE THE INCREASING INSTABILITY...DO NOT EXPECT SEVERE
STORMS.
TEMPERATURES TODAY WILL AGAIN BE ON THE INCREASE...WITH HIGH TEMPS
PROGGED IN THE 70S JUST ABOUT EVERYWHERE. HAVE GENERALLY SIDED
WITH THE WARMER MET/GFS TEMPS AS IT IS IN BETTER AGREEMENT WITH
ECMWF.
THE FRONT MOVES THROUGH THE AREA LATE TONIGHT INTO EARLY
WEDNESDAY...BUT IN THE END IT IS HARDLY ANYTHING MORE THAN A
BRIEF WIND SHIFT AS ALL DYNAMICS REMAIN TO THE NORTH. TEMPERATURES
WILL REMAIN VERY WARM...CLIMBING INTO THE 80S IN MANY AREAS /STILL
BELOW RECORD HIGHS/. THE FRONT WILL DO LITTLE TO SENSIBLE WEATHER
EXCEPT TO PUSH THE BETTER MOISTURE SOUTH...AND THUS HAVE TRENDED
POPS DOWN FOR WEDNESDAY AFTERNOON WITH ONLY SLIGHT CHANCE
REMAINING SOUTH AND NO POPS FOR WEDNESDAY NIGHT. THIS IS SHORT-
LIVED...HOWEVER...AS RIDGING BUILDING IN ALOFT AND CONTINUED
SOUTHERLY FLOW WILL BRING MOISTURE BACK TO THE REGION FOR THE
EXTENDED.
TDP
LONG TERM /THURSDAY THROUGH MONDAY/...
ECMWF AND GFS KEEP A PROGRESSIVE FLOW OVER THE CWA AT THE EARLY PART
OF THE LONG TERM...BUT THEN BUILDS A LARGE H5 RIDGE OVER THE EASTERN
U.S. DURING THE WEEKEND WHICH WILL HOLD INTO THE EARLY PART OF NEXT
WEEK. FOR THURSDAY AND FRIDAY...A SERIES OF SHORT WAVES WILL MOVE
THROUGH THE FLOW KEEPING THE RISK OF SHOWERS/THUNDERSTORMS OVER THE
CWA. MODELS BEGIN DIFFERING ON THE SOLUTION FOR THE WEEKEND. GFS
DOESNT CLEAR OUT THE MOISTURE COMPLETELY AND THIS WOULD KEEP THE
RISK OF SHOWERS/THUNDERSTORMS IN THE FORECAST THROUGH THE WEEKEND.
THE ECMWF BUILDS A RIDGE OF HIGH PRESSURE AT THE SURFACE WHICH NOSES
INTO THE CWA. THIS BRINGS MORE STABLE AND SLIGHTLY COOLER AIR INTO
THE CWA...BUT CONTINUES TO HOLD ON TO MOISTURE. THE END RESULT OF
BOTH MODELS IS THERE IS ENOUGH MOISTURE TO KEEP THE RISK OF AT LEAST
SHOWERS IN THE LONG TERM FOR THE WEEKEND AND INTO EARLY NEXT WEEK.
MEX GUIDANCE IS INDICATING RECORD OR NEAR RECORD HIGH TEMPS FOR
THURSDAY AND FRIDAY WITH A SLIGHT COOL DOWN FOR THE WEEKEND AND INTO
EARLY NEXT WEEK AS THE SURFACE FLOW BECOMES EAST TO NORTHEAST. THIS
IS THE SECOND NIGHT IN A ROW THAT THE MODELS ARE GOING FOR
RECORD/NEAR RECORD TEMPS AND SEE NO REASON TO GO AGAINST THIS AT
THIS TIME.
17
&&
.AVIATION...
18Z UPDATE...
IMMEDIATE CONCERN IS LIKELIHOOD AND COVERAGE OF SHRA OR EVEN TSRA
THIS AFTERNOON. CONTINUE TO SEE ISOLD SHRA...SOME HEAVY...OVER ATL
METRO AND ALL AREAS SOUTH. WITH THIS COVERAGE...USED VCSH IN MOST
AREAS. ADDED VCTS AT KMCN AND KCSG WHERE COVERAGE OF SHRA/TSRA WILL
BE MORE WIDESPREAD. OTHER CONCERN IS POSSIBILITY OF RADIATIONAL
FOG/STRATUS LATE TONIGHT. NO FRONT OR DRY ADVECTION EXPECTED TO
PUSH IN BEHIND PRECIP TONIGHT...SO DEWPOINTS WILL REMAIN HIGH. IF
WE GET ENOUGH CLEARING AND CALM SFC WINDS SHOULD SEE FAIRLY GOOD
FOG EVENT. NOT SURE WE AGREE WITH GUIDANCE FCSTS OF LIFR VSBYS WITH
NO CIGS IN THIS PATTERN SO HAVE KEPT VSBYS AT 1-2SM WITH CIGS OF
500FT FROM 10Z-13Z. IFR RADIATIONAL FOG VERY RARE AT KATL
...PERHAPS THERE IS AN ISSUE WITH GUIDANCE THIS TIME OF YEAR. NO
OTHER PROBLEMS EXPECTED.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON PRECIP COVERAGE THIS AFTERNOON AND IFR
CIGS/VSBYS THIS MORNING. HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 74 53 83 52 / 80 10 10 5
ATLANTA 73 57 81 59 / 90 10 10 5
BLAIRSVILLE 71 51 76 49 / 60 10 10 5
CARTERSVILLE 76 50 80 49 / 90 10 10 10
COLUMBUS 74 56 83 56 / 90 10 20 5
GAINESVILLE 72 54 80 56 / 90 10 10 5
MACON 75 54 83 50 / 60 10 20 5
ROME 77 51 81 50 / 70 10 10 10
PEACHTREE CITY 73 50 80 46 / 90 10 10 5
VIDALIA 80 59 84 58 / 30 10 20 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
13
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1226 PM EDT TUE MAR 13 2012
.SYNOPSIS...
A WEAK FRONT WILL CROSS THE REGION TODAY WITH THE CHANCE FOR
SHOWERS AND PERHAPS A THUNDERSTORM. HIGH PRESSURE WILL THEN BRING
DRY AND WARM WEATHER UNTIL THE APPROACH OF AN UPPER DISTURBANCE ON
THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHOWERS FELL APART ACROSS THE CWA AS HRRR INDICATED. CLOUD COVER
REMAINS ACROSS THE SOUTHERN HALF OF THE CWA. ADJUSTED CLOUD GRIDS
TO REFLECT IT.
BEHIND THE BOUNDARY A SLIGHT COOL DOWN FOR TONIGHT WITH LOWS INTO
THE 40S, AND READINGS IN THE UPPER 30S ACROSS THE NORTHERN TIER.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
A BROAD RIDGE OF HIGH PRESSURE WILL BE OVER MUCH OF THE EASTERN
STATES WITH THE RIDGE AXIS SLIDING ACROSS THE GREAT LAKES. DRY
WEATHER AND WARM TEMPERATURES MAY THUS BE EXPECTED UNTIL A
SHORTWAVE IN SOUTHWESTERLY FLOW PROVIDES A SHOWER AND THUNDERSTORM
CHANCE ON THURSDAY.
TEMPERATURE READINGS WERE FORECAST ABOUT 20 DEGREES ABOVE THE
SEASONAL AVERAGES USING A GUIDANCE BLEND.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
BLEND OF HPC-PREFERRED ECMWF ENSEMBLE MEAN AND NAEFS MODEL OUTPUT
SHOW DEEP TROUGHING ALONG THE PACIFIC COAST RESULTING IN AN
AMPLIFYING RIDGE OVER THE EASTERN CONUS BY NEXT WEEKEND. THIS
PATTERN WOULD ENSURE CONTINUED WARMTH FOR THE UPPER OHIO VALLEY
REGION DURING THE LONG TERM PERIOD AS WELL AS DIMINISHING PRECIP
PROBABILITIES FOLLOWING PASSAGE OF THE AFOREMENTIONED
THURSDAY/FRIDAY SHORTWAVE.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
WARM FRONT HAS SHIFTED JUST FAR ENOUGH NORTH TO ALLOW FOR A PERIOD
OF VFR CONDITIONS ACROSS SOUTHERN PORTS. HOWEVER, ACROSS THE NORTH
IFR TO LOW MVFR CONDITIONS CONTINUE AND WILL DO SO THROUGH THE
MORNING HOURS. AS COLD FRONT APPROACHES, SOUTHERN PORTS WILL LOWER
TO MVFR WITH OCCASIONAL IFR POSSIBLE. SOUTHERLY SFC WINDS WILL
GENERALLY BE FROM 10 TO 15KTS THROUGH THE MORNING, WITH GUSTS TO 20
KTS POSSIBLE. AHEAD OF THE FRONT, SCT SHOWERS, WITH AN ISO TRW, IS
POSSIBLE AT FKL AND DUJ AROUND DAWN. DRIER AIR WILL MOVE IN BEHIND
THE COLD FRONT THIS AFTERNOON BRINGING A RETURN TO VFR CONDITIONS.
WINDS WILL BECOME WESTERLY DURING THE LATE MORNING/EARLY AFTERNOON
HOURS WITH GUSTS TO 20KTS POSSIBLE.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
VFR THROUGH THURSDAY. SHOWERS WILL BE POSSIBLE THURSDAY NIGHT THROUGH
SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
647 PM EDT TUE MAR 13 2012
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL EXTEND WESTWARD ACROSS THE EASTERN
CAROLINAS INTO EARLY NEXT WEEK. SOUTHERLY WINDS WILL BRING WARM
TEMPERATURES. A WEAK FRONT MAY BRIEFLY REACH THE AREA WEDNESDAY
BEFORE DISSIPATING. THERE WILL BE SOME OPPORTUNITY FOR RAINFALL
INTO TONIGHT...AND THEN AGAIN DURING THE WEEKEND AS A COLD FRONT
APPROACHES THE AREA.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 6:45 PM TUESDAY...HAVE DROPPED POPS TO THE SLIGHT CHANCE
CATEGORY AND ELIMINATED QPF FOR THE EVENING HOURS. CONVECTION JUST
CANNOT GET GOING LATE THIS AFTERNOON. RADAR LOOPS SHOW SOME BRIEF
FLARE-UPS OVER OUR SC COUNTIES...THEN A FEW SCANS LATER...GONE.
WATER VAPOR LOOPS SHOW BULK OF SHORT WAVE ENERGY PASSING TO OUR
SOUTH AND WITH LOSS OF DAYTIME HEATING SEE LITTLE IN THE WAY OF
TRIGGERS FOR SIGNIFICANT CONVECTION FOR THE REMAINDER OF THE NEAR
TERM. NEXT UPDATE WILL LIKELY ELIMINATE POPS COMPLETELY. HAVE ALSO
ADJUSTED THE TEMPERATURE CURVE UPWARDS BY A FEW DEGREES FOR THE
AFTERNOON AND EVENING HOURS. LATEST OBS SHOW PLENTY OF MID 70S AND
EVEN SOME UPPER 70S WELL INLAND. PREVIOUS DISCUSSION FOLLOWS:
SHORTWAVE EVIDENT ON WV IMAGERY MOVING ACROSS THE UPSTATE OF SC IS
CREATING SOME SCATTERED SHOWERS/TSTMS WHICH ARE PUSHING EAST
TOWARDS THE ILM CWA. THIS ACTIVITY IS NOT AS WIDESPREAD AS
PREVIOUSLY ANTICIPATED...WHICH IS INTERESTING SINCE CLOUDS HAVE
BROKEN...WHICH WAS EXPECTED TO BE THE LIMITING FACTOR TO
CONVECTIVE TRIGGER. A GLANCE AT LATEST RUC SOUNDINGS INDICATE A
SUBADIABATIC LAYER BETWEEN 950MB-800MB WHICH IS LIKELY ACTING AS A
WEAK CAP TO INHIBIT SURFACE PARCELS FROM BECOMING UNSTABLE...AND
LACK OF AGITATED CU IN THE CLEAR BREAKS IS A FURTHER SIGNAL OF
THIS. APPEARS THE NAM/SREF ARE OVERDOING CONVECTIVE POTENTIAL
THROUGH TONIGHT...SO HAVE TRIMMED SPATIAL COVERAGE OF CHANCE POP.
EXPECT THE AREA OF TSTMS JUST AHEAD OF THE S/W TO PUSH EAST AND
SURVIVE TO THE COAST IN THE NEXT SEVERAL HOURS...WITH HIGH CHANCE
TSTMS FROM ALONG AND SOUTH OF A LINE FROM HVS...TO MYR.
OTHERWISE...NO SIGNIFICANT PRECIP EXPECTED TO DEVELOP...WITH ONLY
SCHC POP ACROSS NORTHERN ZONES THROUGH TONIGHT BEFORE ACTIVITY
WILL ERODE DIURNALLY.
ONE LAST S/W WILL PIVOT THROUGH TONIGHT AND A WEAK COLD FRONT
APPROACHES FROM THE NW TRAILED FROM A LOW MOVING ACROSS NEW
ENGLAND. LATEST GUIDANCE HAS SPED UP THIS FRONT JUST
SLIGHTLY...AND HAVE VEERED WINDS TO THE WEST BY MORNING WEDNESDAY.
THIS FRONT ACTS AS THE MAIN PLAYER INTO FOG/STRATUS DEVELOPMENT
OVERNIGHT. DO NOT EXPECT FULL DECOUPLING SINCE THE GRADIENT WILL
REMAIN SLIGHTLY PINCHED...AND MET/MAV WIND VALUES REFLECT THIS
WELL. AT THE SAME TIME...FORECAST SOUNDINGS DEPICT A LLJ OF AROUND
20 KTS JUST ABOVE THE SURFACE INVERSION...ALL OF THESE WOULD POINT
TOWARDS A STRATUS EVENT TONIGHT IN THE MOIST ATMOSPHERE AS OPPOSED
TO FOG. HOWEVER...MODERATELY STEEP LOW LEVEL HYDROLAPSE RATES AND
CLEARING SKY CONDITIONS FAVOR FOG...AND CROSSOVER TEMPS WILL
LIKELY BE REACHED AT MOST LOCALES. FOR THIS REASON HAVE KEPT AREAS
OF FOG TO BE CONSISTENT WITH NEIGHBORS...BUT NOT MENTIONED
WIDESPREAD FOR THE POTENTIAL OF MORE STRATUS THAN FOG. HAVE
DROPPED MINS A DEGREE ACROSS THE BOARD FOR THE SLIGHTLY FASTER
VEER IN WIND DIRECTION...WITH LOW 50S FAR NW AND MID 50S AT THE
COAST. IF STRATUS BECOMES PREDOMINANT OR DEVELOPS MORE
RAPIDLY...THESE MINS MAY BE A BIT TOO COOL.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...FAIR WEATHER EXPECTED THROUGH THE PERIOD AS
HIGH PRESSURE CONTROLS AREA WEATHER. EXPECT HIGHS EACH DAY IN THE
UPPER 70S TO LOWER 80S...PERHAPS MID 80S WELL INLAND...WITH COOLER
ON TAP NEARER THE BEACHES. LOWS EACH NIGHT WILL FALL INTO THE
MIDDLE 50S. AFTER WEDNESDAY MORNING...SKIES SHOULD BE MAINLY CLEAR
THOUGH SOME INCREASE IN CLOUDS IS POSSIBLE IN ADVANCE OF THE NEXT
SYSTEM THURSDAY NIGHT. IT IS WORTH NOTING THAT ISOLATED SHOWERS ARE
POSSIBLE ALONG THE SEA BREEZE EACH AFTERNOON BUT THE PROBABILITY OF
SHOWERS IS LOW ENOUGH THAT MENTION IN THE FORECAST IS NOT WARRANTED
AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...DECENT MODEL COHESIVENESS FRIDAY THROUGH
TUESDAY IN DEPICTING A DEVELOPING OMEGA-BLOCK PATTERN OVER THE
CONUS...WITH SUBTLE BUT IMPORTANT DIFFERENCES IN THE LONGITUDINAL
PLACEMENT OF THE OMEGA-RIDGE AXIS. THE FARTHER WEST POSITIONING
OFFERED IN THE ECMWF IMPLIES A MARITIME OR COASTAL-LOW INFLUENCE
IN OUR FORECASTS...WHEREAS THE GFS ENVELOPS THE REGION IN AN
AMPLIFYING UPPER RIDGE THROUGH THE EVOLUTION OF THE OMEGA-BLOCK
FORMATION...YIELDING WARM AND DRY. HAVE OPTED FOR SLIGHTLY LESS
AMPLIFIES SOLUTION TO THE GFS.
AT THE SURFACE...A WEAK SURFACE TROUGH WILL RESIDE ACROSS THE AREA
LATE FRIDAY THROUGH SATURDAY WITH ENOUGH MOISTURE TO WARRANT
MENTIONABLE POP VALUES. THE BOUNDARY WILL STALL SOUTH OF OUR AREA
SUNDAY ONWARD. RETURN FLOW SHOULD BRING A SLIGHT CHANCE OF SHOWERS
BY TUE. THIS PERIOD WILL BE MARKED BY ABOVE NORMAL TEMPERATURES
SINCE WE WILL BE IMPACTED BY THE RIDGE PORTION OF THE OMEGA-BLOCK.
THE COLD FRONTS WILL BE SHALLOW AND THE UPPER RIDGE WILL BE HIGHLY
AMPLIFIED OVER OR JUST WEST OF THE FORECAST AREA.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 18Z...AN APPROACHING SHORTWAVE OVER WESTERN SOUTH CAROLINA
WILL SHIFT ACROSS THE TAF SITES AND WILL EXIT THE COAST BY 00 UTC.
THERE IS A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. AT
THIS TIME FORCING IS WEAK SO HAVE ONLY GONE WITH A MENTION OF VCSH.
CLEARING AHEAD OF THE VORTICITY MAXIMUM WILL ALLOW FOR SOME HEATING
BUT WILL REMAIN WITH SHOWERS AT THIS TIME.
TONIGHT DECENT LOW LEVEL MOISTURE...AND LIGHT WINDS AT THE SURFACE
MAY INDUCE THE DEVELOPMENT OF FOG. A NEGATIVE INFLUENCE WILL BE THE
POSSIBLE DEVELOPMENT OF A LOW LEVEL JET AT 22 TO 25 KNOTS BETWEEN 1
AND 2 THOUSAND FEET AT ALL TAF SITES. THIS MAY HELP THE DEVELOPMENT
OF A STRATUS LAYER AND WILL INHIBIT DENSE FOG FROM DEVELOPING. SO AT
THIS TIME HAVE PUT THE MENTION OF IFR CEILINGS AND MVFR RESTRICTION
TO VISION STARTING AT 08 UTC.
EXTENDED OUTLOOK...MORNING IFR FOG POSSIBLE THURSDAY. VFR FRIDAY.
SHOWERS POSSIBLE LATE FRIDAY INTO SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:45 PM TUESDAY...WINDS HAVE PICKED UP A TAD OVER THE WATERS
BUT ARE STILL LIGHT...IN THE 10 KNOT RANGE EXCEPT NEAR THE COAST
WHERE THE SEA BREEZE CIRCULATION IS KICKING WINDS UP INTO THE 15
KT RANGE. SEAS RIGHT AROUND 2 TO 3 FT THIS EVENING. NO CHANGES
ANTICIPATED TO GOING FORECAST. PREVIOUS DISCUSSION FOLLOWS:
VERY LIGHT GRADIENT OVER THE WATERS CONTRIBUTING TO WINDS LESS
THAN 5 KTS AT ALL BUOYS. OF COURSE WITH NO WIND...THERE IS NO
MEANINGFUL WIND CHOP...AND THE WAVE SPECTRUM IS COMPLETELY
DOMINATED BY A SE 3FT/9SEC SWELL. THIS SWELL HAS ERODED A BIT ON
ACCOUNT OF THE POSITIONING OF THE OFFSHORE RIDGE NOT ALLOWING FOR
IDEAL SE FETCH...SO WAVE GUIDANCE HAS OVERESTIMATED SEAS BY ABOUT
A FOOT THIS AFTN...AND SEAS OF ONLY 2-3 FT PRESENTLY OCCURRING.
EXPECT FAIRLY UNIFORM WIND/WAVE CONDITIONS THROUGH
NIGHTFALL...BEFORE WINDS WILL INCREASE TO AROUND 10 KTS AS
GRADIENT BECOMES PINCHED JUST SLIGHTLY AND AIR TEMPS FALL TO
VALUES BELOW OCEAN TEMPS. THIS WILL CREATE SEAS BUILDING TO 3-4 FT
BY TUESDAY MORNING.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...GENERALLY EXPECT LIGHT SW FLOW THROUGH THE
PERIOD BUT THE PRESSURE GRADIENT WILL BE WEAK ENOUGH DURING THE
PERIOD THAT THE SEA BREEZE BY DAY AND LAND BREEZE BY NIGHT COULD
BECOME DOMINANT AT TIMES. THIS COULD PRODUCE S TO SE WINDS NEAR
SHORE IN THE AFTERNOON AND MORE WESTERLY WINDS OVERNIGHT. SPEEDS
WILL REMAIN BELOW 15 KT THROUGH THE PERIOD WITH MAXIMUM SEAS OF 3 FT
EXPECTED.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...DECENT MARINE CONDITIONS FRI-SUN WITH
SUB-ADVISORY SW WINDS FRI AND SAT AHEAD OF AN INLAND SURFACE
TROUGH. THIS FEATURE WILL PUSH SOUTH OF OUR WATERS AS A COLD FRONT
SUNDAY WITH NE WIND FLOW BEHIND IT...BUT BELOW ADVISORY WIND SPEEDS
EXPECTED. IT WILL BE A BUMPY 3-4 FEET SUNDAY...AS THE NNE WIND-
WAVES CO-MINGLE WITH RESIDUAL SOUTH WAVE ENERGY. A FEW SHOWERS
POSSIBLE FRI AND SAT BUT NO TSTMS EXPECTED. PATCHY INSHORE FOG IS
POSSIBLE LATE FRIDAY AND SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...REK/JDW
SHORT TERM...RAN
LONG TERM...MJC
AVIATION...99
MARINE...MJC/REK/JDW/RAN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
302 PM EDT TUE MAR 13 2012
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL RIDGE WESTWARD ACROSS THE EASTERN
CAROLINAS INTO EARLY NEXT WEEK. SOUTHERLY WINDS WILL BRING WARM
TEMPERATURES. A WEAK FRONT MAY BRIEFLY REACH THE AREA WEDNESDAY
BEFORE DISSIPATING. THERE WILL BE SOME OPPORTUNITY FOR RAINFALL INTO
TONIGHT...AND THEN AGAIN DURING THE WEEKEND AS A COLD FRONT
APPROACHES THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM TUESDAY...SHORTWAVE EVIDENT ON WV IMAGERY MOVING ACROSS
THE UPSTATE OF SC IS CREATING SOME SCATTERED SHOWERS/TSTMS WHICH ARE
PUSHING EAST TOWARDS THE ILM CWA. THIS ACTIVITY IS NOT AS WIDESPREAD
AS PREVIOUSLY ANTICIPATED...WHICH IS INTERESTING SINCE CLOUDS HAVE
BROKEN...WHICH WAS EXPECTED TO BE THE LIMITING FACTOR TO CONVECTIVE
TRIGGER. A GLANCE AT LATEST RUC SOUNDINGS INDICATE A SUBADIABATIC
LAYER BETWEEN 950MB-800MB WHICH IS LIKELY ACTING AS A WEAK CAP TO
INHIBIT SURFACE PARCELS FROM BECOMING UNSTABLE...AND LACK OF
AGITATED CU IN THE CLEAR BREAKS IS A FURTHER SIGNAL OF THIS. APPEARS
THE NAM/SREF ARE OVERDOING CONVECTIVE POTENTIAL THROUGH TONIGHT...SO
HAVE TRIMMED SPATIAL COVERAGE OF CHANCE POP. EXPECT THE AREA OF
TSTMS JUST AHEAD OF THE S/W TO PUSH EAST AND SURVIVE TO THE COAST IN
THE NEXT SEVERAL HOURS...WITH HIGH CHANCE TSTMS FROM ALONG AND SOUTH
OF A LINE FROM HVS...TO MYR. OTHERWISE...NO SIGNIFICANT PRECIP
EXPECTED TO DEVELOP...WITH ONLY SCHC POP ACROSS NORTHERN ZONES
THROUGH TONIGHT BEFORE ACTIVITY WILL ERODE DIURNALLY.
ONE LAST S/W WILL PIVOT THROUGH TONIGHT AND A WEAK COLD FRONT
APPROACHES FROM THE NW TRAILED FROM A LOW MOVING ACROSS NEW ENGLAND.
LATEST GUIDANCE HAS SPED UP THIS FRONT JUST SLIGHTLY...AND HAVE
VEERED WINDS TO THE WEST BY MORNING WEDNESDAY.
THIS FRONT ACTS AS THE MAIN PLAYER INTO FOG/STRATUS DEVELOPMENT
OVERNIGHT. DO NOT EXPECT FULL DECOUPLING SINCE THE GRADIENT WILL
REMAIN SLIGHTLY PINCHED...AND MET/MAV WIND VALUES REFLECT THIS WELL.
AT THE SAME TIME...FORECAST SOUNDINGS DEPICT A LLJ OF AROUND 20 KTS
JUST ABOVE THE SURFACE INVERSION...ALL OF THESE WOULD POINT TOWARDS
A STRATUS EVENT TONIGHT IN THE MOIST ATMOSPHERE AS OPPOSED TO FOG.
HOWEVER...MODERATELY STEEP LOW LEVEL HYDROLAPSE RATES AND CLEARING
SKY CONDITIONS FAVOR FOG...AND CROSSOVER TEMPS WILL LIKELY BE
REACHED AT MOST LOCALES. FOR THIS REASON HAVE KEPT AREAS OF FOG TO
BE CONSISTENT WITH NEIGHBORS...BUT NOT MENTIONED WIDESPREAD FOR THE
POTENTIAL OF MORE STRATUS THAN FOG. HAVE DROPPED MINS A DEGREE
ACROSS THE BOARD FOR THE SLIGHTLY FASTER VEER IN WIND
DIRECTION...WITH LOW 50S FAR NW AND MID 50S AT THE COAST. IF STRATUS
BECOMES PREDOMINANT OR DEVELOPS MORE RAPIDLY...THESE MINS MAY BE A
BIT TOO COOL.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...FAIR WEATHER EXPECTED THROUGH THE PERIOD AS
HIGH PRESSURE CONTROLS AREA WEATHER. EXPECT HIGHS EACH DAY IN THE
UPPER 70S TO LOWER 80S...PERHAPS MID 80S WELL INLAND...WITH COOLER
ON TAP NEARER THE BEACHES. LOWS EACH NIGHT WILL FALL INTO THE
MIDDLE 50S. AFTER WEDNESDAY MORNING...SKIES SHOULD BE MAINLY CLEAR
THOUGH SOME INCREASE IN CLOUDS IS POSSIBLE IN ADVANCE OF THE NEXT
SYSTEM THURSDAY NIGHT. IT IS WORTH NOTING THAT ISOLATED SHOWERS ARE
POSSIBLE ALONG THE SEA BREEZE EACH AFTERNOON BUT THE PROBABILITY OF
SHOWERS IS LOW ENOUGH THAT MENTION IN THE FORECAST IS NOT WARRANTED
AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...DECENT MODEL COHESIVENESS FRIDAY THROUGH
TUESDAY IN DEPICTING A DEVELOPING OMEGA-BLOCK PATTERN OVER THE
CONUS...WITH SUBTLE BUT IMPORTANT DIFFERENCES IN THE LONGITUDINAL
PLACEMENT OF THE OMEGA-RIDGE AXIS. THE FARTHER WEST POSITIONING
OFFERED IN THE ECMWF IMPLIES A MARITIME OR COASTAL-LOW INFLUENCE
IN OUR FORECASTS...WHEREAS THE GFS ENVELOPS THE REGION IN AN
AMPLIFYING UPPER RIDGE THROUGH THE EVOLUTION OF THE OMEGA-BLOCK
FORMATION...YIELDING WARM AND DRY. HAVE OPTED FOR SLIGHTLY LESS
AMPLIFIES SOLUTION TO THE GFS.
AT THE SURFACE...A WEAK SURFACE TROUGH WILL RESIDE ACROSS THE AREA
LATE FRIDAY THROUGH SATURDAY WITH ENOUGH MOISTURE TO WARRANT
MENTIONABLE POP VALUES. THE BOUNDARY WILL STALL SOUTH OF OUR AREA
SUNDAY ONWARD. RETURN FLOW SHOULD BRING A SLIGHT CHANCE OF SHOWERS
BY TUE. THIS PERIOD WILL BE MARKED BY ABOVE NORMAL TEMPERATURES
SINCE WE WILL BE IMPACTED BY THE RIDGE PORTION OF THE OMEGA-BLOCK.
THE COLD FRONTS WILL BE SHALLOW AND THE UPPER RIDGE WILL BE HIGHLY
AMPLIFIED OVER OR JUST WEST OF THE FORECAST AREA.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...AN APPROACHING SHORTWAVE OVER WESTERN SOUTH CAROLINA
WILL SHIFT ACROSS THE TAF SITES AND WILL EXIT THE COAST BY 00 UTC.
THERE IS A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. AT
THIS TIME FORCING IS WEAK SO HAVE ONLY GONE WITH A MENTION OF VCSH.
CLEARING AHEAD OF THE VORTICITY MAXIMUM WILL ALLOW FOR SOME HEATING
BUT WILL REMAIN WITH SHOWERS AT THIS TIME.
TONIGHT DECENT LOW LEVEL MOISTURE...AND LIGHT WINDS AT THE SURFACE
MAY INDUCE THE DEVELOPMENT OF FOG. A NEGATIVE INFLUENCE WILL BE THE
POSSIBLE DEVELOPMENT OF A LOW LEVEL JET AT 22 TO 25 KNOTS BETWEEN 1
AND 2 THOUSAND FEET AT ALL TAF SITES. THIS MAY HELP THE DEVELOPMENT
OF A STRATUS LAYER AND WILL INHIBIT DENSE FOG FROM DEVELOPING. SO AT
THIS TIME HAVE PUT THE MENTION OF IFR CEILINGS AND MVFR RESTRICTION
TO VISION STARTING AT 08 UTC.
EXTENDED OUTLOOK...MORNING IFR FOG POSSIBLE THURSDAY. VFR FRIDAY.
SHOWERS POSSIBLE LATE FRIDAY INTO SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM TUESDAY...VERY LIGHT GRADIENT OVER THE WATERS
CONTRIBUTING TO WINDS LESS THAN 5 KTS AT ALL BUOYS. OF COURSE WITH
NO WIND...THERE IS NO MEANINGFUL WIND CHOP...AND THE WAVE SPECTRUM
IS COMPLETELY DOMINATED BY A SE 3FT/9SEC SWELL. THIS SWELL HAS
ERODED A BIT ON ACCOUNT OF THE POSITIONING OF THE OFFSHORE RIDGE NOT
ALLOWING FOR IDEAL SE FETCH...SO WAVE GUIDANCE HAS OVERESTIMATED
SEAS BY ABOUT A FOOT THIS AFTN...AND SEAS OF ONLY 2-3 FT PRESENTLY
OCCURRING. EXPECT FAIRLY UNIFORM WIND/WAVE CONDITIONS THROUGH
NIGHTFALL...BEFORE WINDS WILL INCREASE TO AROUND 10 KTS AS GRADIENT
BECOMES PINCHED JUST SLIGHTLY AND AIR TEMPS FALL TO VALUES BELOW
OCEAN TEMPS. THIS WILL CREATE SEAS BUILDING TO 3-4 FT BY TUESDAY
MORNING.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...GENERALLY EXPECT LIGHT SW FLOW THROUGH THE
PERIOD BUT THE PRESSURE GRADIENT WILL BE WEAK ENOUGH DURING THE
PERIOD THAT THE SEA BREEZE BY DAY AND LAND BREEZE BY NIGHT COULD
BECOME DOMINANT AT TIMES. THIS COULD PRODUCE S TO SE WINDS NEAR
SHORE IN THE AFTERNOON AND MORE WESTERLY WINDS OVERNIGHT. SPEEDS
WILL REMAIN BELOW 15 KT THROUGH THE PERIOD WITH MAXIMUM SEAS OF 3 FT
EXPECTED.
LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...DECENT MARINE CONDITIONS FRI-SUN WITH
SUB-ADVISORY SW WINDS FRI AND SAT AHEAD OF AN INLAND SURFACE
TROUGH. THIS FEATURE WILL PUSH SOUTH OF OUR WATERS AS A COLD FRONT
SUNDAY WITH NE WIND FLOW BEHIND IT...BUT BELOW ADVISORY WIND SPEEDS
EXPECTED. IT WILL BE A BUMPY 3-4 FEET SUNDAY...AS THE NNE WIND-
WAVES CO-MINGLE WITH RESIDUAL SOUTH WAVE ENERGY. A FEW SHOWERS
POSSIBLE FRI AND SAT BUT NO TSTMS EXPECTED. PATCHY INSHORE FOG IS
POSSIBLE LATE FRIDAY AND SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...31
LONG TERM...MJC
AVIATION...HAWKINS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
216 PM EDT TUE MAR 13 2012
.SYNOPSIS...
HIGH PRESSURE OFFSHORE WILL RIDGE WESTWARD ACROSS THE EASTERN
CAROLINAS INTO EARLY NEXT WEEK. SOUTHERLY WINDS WILL BRING WARM
TEMPERATURES. A WEAK FRONT MAY BRIEFLY REACH THE AREA WEDNESDAY
BEFORE DISSIPATING. THERE WILL BE SOME OPPORTUNITY FOR RAINFALL
TODAY...AND THEN AGAIN DURING THE WEEKEND AS A COLD FRONT APPROACHES
THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM TUESDAY...SHORTWAVE EVIDENT ON WV IMAGERY MOVING ACROSS
THE UPSTATE OF SC IS CREATING SOME SCATTERED SHOWERS/TSTMS WHICH ARE
PUSHING EAST TOWARDS THE ILM CWA. THIS ACTIVITY IS NOT AS WIDESPREAD
AS PREVIOUSLY ANTICIPATED...WHICH IS INTERESTING SINCE CLOUDS HAVE
BROKEN...WHICH WAS EXPECTED TO BE THE LIMITING FACTOR TO CONVECTIVE
TRIGGER. A GLANCE AT LATEST RUC SOUNDINGS INDICATE A NEARLY
ISOTHERMAL LAYER BETWEEN 950MB-800MB WHICH IS LIKELY ACTING AS A
WEAK CAP TO INHIBIT SURFACE PARCELS FROM BECOMING UNSTABLE...AND
LACK OF AGITATED CU IN THE CLEAR BREAKS IS A FURTHER SIGNAL OF THIS.
APPEARS THE NAM/SREF ARE OVERDOING CONVECTIVE POTENTIAL THROUGH
TONIGHT...SO HAVE TRIMMED SPATIAL COVERAGE OF CHANCE POP. EXPECT THE
AREA OF TSTMS JUST AHEAD OF THE S/W TO PUSH EAST AND SURVIVE TO THE
COAST IN THE NEXT SEVERAL HOURS...WITH HIGH CHANCE TSTMS FROM ALONG
AND SOUTH OF A LINE FROM HVS...TO MYR. OTHERWISE...NO SIGNIFICANT
PRECIP EXPECTED TO DEVELOP...WITH ONLY SCHC POP ACROSS NORTHERN
ZONES THROUGH TONIGHT BEFORE ACTIVITY WILL ERODE DIURNALLY.
ONE LAST S/W WILL PIVOT THROUGH TONIGHT AND A WEAK COLD FRONT
APPROACHES FROM THE NW TRAILED FROM A LOW MOVING ACROSS NEW ENGLAND.
LATEST GUIDANCE HAS SPED UP THIS FRONT JUST SLIGHTLY...AND HAVE
VEERED WINDS TO THE WEST BY MORNING WEDNESDAY.
THIS FRONT ACTS AS THE MAIN PLAYER INTO FOG/STRATUS DEVELOPMENT
OVERNIGHT. DO NOT EXPECT FULL DECOUPLING SINCE THE GRADIENT WILL
REMAIN SLIGHTLY PINCHED...AND MET/MAV WIND VALUES REFLECT THIS WELL.
AT THE SAME TIME...FORECAST SOUNDINGS DEPICT A LLJ OF AROUND 20 KTS
JUST ABOVE THE SURFACE INVERSION...ALL OF THESE WOULD POINT TOWARDS
A STRATUS EVENT TONIGHT IN THE MOIST ATMOSPHERE AS OPPOSED TO FOG.
HOWEVER...MODERATELY STEEP LOW LEVEL HYDROLAPSE RATES AND CLEARING
SKY CONDITIONS FAVOR FOG...AND CROSSOVER TEMPS WILL LIKELY BE
REACHED AT MOST LOCALES. FOR THIS REASON HAVE KEPT AREAS OF FOG TO
BE CONSISTENT WITH NEIGHBORS...BUT NOT MENTIONED WIDESPREAD FOR THE
POTENTIAL OF MORE STRATUS THAN FOG. HAVE DROPPED MINS A DEGREE
ACROSS THE BOARD FOR THE SLIGHTLY FASTER VEER IN WIND
DIRECTION...WITH LOW 50S FAR NW AND MID 50S AT THE COAST. IF STRATUS
BECOMES PREDOMINANT OR DEVELOPS MORE RAPIDLY...THESE MINS MAY BE A
BIT TOO COOL.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...DRY ADVECTION AND HEIGHT RISES BEHIND TUESDAY`S
WEAK DISTURBANCE WILL BRING A DRY AND UNSEASONABLY WARM DAY ON
WEDNESDAY. SURFACE FLOW LOOKS VERY LIGHT DUE TO DISSIPATING TROUGH
COMING THROUGH FROM THE NORTH. GIVEN THE WARMTH A STRONG SEA BREEZE
CIRCULATION SHOULD DEVELOP ALTHOUGH ITS INLAND PROGRESSION WILL BE
HINDERED SLIGHTLY BY THE OFFSHORE BOUNDARY LAYER WINDS. UPPER RIDGE
TRIES TO CONTINUE TO BUILD IN AMPLITUDE ON THURSDAY BUT IS HELD BACK
BY UPPER LOW DEEPENING OFF OF NEW ENGLAND COAST. SURFACE GRADIENT
REMAINS QUITE LIGHT AND SO BASICALLY LOOKING FOR LARGELY A REPEAT
FORECAST. AFTERNOON HIGHS WELL ABOVE CLIMO AND A COOLING SEA BREEZE
ALONG THE IMMEDIATE COAST. MAIN DIFFERENCE IS THAT THURSDAY SEA
BREEZE WILL MOVE FURTHER INLAND DUE TO LESS OF A DEFINED OFFSHORE
FLOW IN THE BL.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...UNSEASONABLE WARMTH WILL CONTINUE TO BE THE
MAIN HEADLINE OF THE LONG TERM. UPPER RIDGE ACROSS MOST OF THE GULF
OF MEXICO WHILE SURFACE HIGH PRESSURE STRUGGLES TO HAVE A
WELL-DEFINED CENTER OFF THE SOUTHEAST COAST. MODELS HAVE BEEN FAIRLY
CONSISTENT IN SHOWING A RIDGE TOPPING SET OF VORT MAXES COMING
ACROSS FRIDAY NIGHT INTO SATURDAY ACCOMPANIED BY A WEAK SURFACE
TROUGH. IT SEEMS PLAUSIBLE THAT THIS SHOULD LEAD TO SOME RAIN
CHANCES EVEN IF ONLY POPS AROUND THE LOW SIDE OF CHANCE RANGE. GFS
SHOWS THIS AS MORE OF A BONA FIDE FRONT WITH SOME SLIGHT COOLING
BEHIND IN STORE FOR THE LATTER PART OF THE LONG TERM (COOLER BUT
STILL ABOVE CLIMO). THE CANADIAN AND EC ARE NOT SO SUGGESTIVE OF
THIS SO FAIRLY SIZABLE DEVIATIONS FROM CLIMO WARMTH WILL REMAIN IN
THE FORECAST.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...AN APPROACHING SHORTWAVE OVER WESTERN SOUTH CAROLINA
WILL SHIFT ACROSS THE TAF SITES AND WILL EXIT THE COAST BY 00 UTC.
THERE IS A SLIGHT CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS. AT
THIS TIME FORCING IS WEAK SO HAVE ONLY GONE WITH A MENTION OF VCSH.
CLEARING AHEAD OF THE VORTICITY MAXIMUM WILL ALLOW FOR SOME HEATING
BUT WILL REMAIN WITH SHOWERS AT THIS TIME.
TONIGHT DECENT LOW LEVEL MOISTURE...AND LIGHT WINDS AT THE SURFACE
MAY INDUCE THE DEVELOPMENT OF FOG. A NEGATIVE INFLUENCE WILL BE THE
POSSIBLE DEVELOPMENT OF A LOW LEVEL JET AT 22 TO 25 KNOTS BETWEEN 1
AND 2 THOUSAND FEET AT ALL TAF SITES. THIS MAY HELP THE DEVELOPMENT
OF A STRATUS LAYER AND WILL INHIBIT DENSE FOG FROM DEVELOPING. SO AT
THIS TIME HAVE PUT THE MENTION OF IFR CEILINGS AND MVFR RESTRICTION
TO VISION STARTING AT 08 UTC.
EXTENDED OUTLOOK...MORNING IFR FOG POSSIBLE THURSDAY. VFR FRIDAY.
SHOWERS POSSIBLE LATE FRIDAY INTO SATURDAY. VFR SUNDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM TUESDAY...VERY LIGHT GRADIENT OVER THE WATERS
CONTRIBUTING TO WINDS LESS THAN 5 KTS AT ALL BUOYS. OF COURSE WITH
NO WIND...THERE IS NO MEANINGFUL WIND CHOP...AND THE WAVE SPECTRUM
IS COMPLETELY DOMINATED BY A SE 3FT/9SEC SWELL. THIS SWELL HAS
ERODED A BIT ON ACCOUNT OF THE POSITIONING OF THE OFFSHORE RIDGE NOT
ALLOWING FOR IDEAL SE FETCH...SO WAVE GUIDANCE HAS OVERESTIMATED
SEAS BY ABOUT A FOOT THIS AFTN...AND SEAS OF ONLY 2-3 FT PRESENTLY
OCCURRING. EXPECT FAIRLY UNIFORM WIND/WAVE CONDITIONS THROUGH
NIGHTFALL...BEFORE WINDS WILL INCREASE TO AROUND 10 KTS AS GRADIENT
BECOMES PINCHED JUST SLIGHTLY AND AIR TEMPS FALL TO VALUES BELOW
OCEAN TEMPS. THIS WILL CREATE SEAS BUILDING TO 3-4 FT BY TUESDAY
MORNING.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...WIND WILL BE LIGHT AND PREDOMINANTLY OUT OF THE
SOUTHWEST ON WEDNESDAY WITH ONLY A 2 TO 3 FT WIND WAVE EXPECTED. A
NEARSHORE SEA BREEZE WILL BE OBSERVED AND IT MAY END UP ADDING SOME
GUSTINESS BUT THE TURN TO ONSHORE DIRECTION WILL BE MORE NOTICEABLE
AS LIGHT BOUNDARY LAYER WINDS WILL FAVOR MODEST GUSTS AT BEST. WIND
DIRECTION THEN STRUGGLES TO BE WELL DEFINED BY THURSDAY AS PRESSURE
GRADIENT WEAKENS. SEAS RELATIVELY UNCHANGED.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...AS WIND REMAINS LIGHT ON FRIDAY A DEFINED
SOUTHWESTERLY DIRECTION MAY GET RE-ESTABLISHED AFTER THURSDAYS
RELATIVE VARIABILITY. THIS WILL BE IN RESPONSE TO THE APPROACH OF A
TROUGH SLATED TO COME THROUGH FRIDAY NIGHT OR SATURDAY. THE VEER
ASSOC WITH THE BOUNDARY WILL DEPEND ON ITS STRENGTH BUT CURRENT
FAVORED SOLUTION KEEPS IT WEAK ENOUGH TO PRECLUDE ANY NORTHERLY
COMPONENT FROM EVER DEVELOPING.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...HAWKINS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
110 PM EDT TUE MAR 13 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL CROSS THE AREA LATER LATER THIS
AFTERNOON AND EVENING...BRINGING WITH IT A CHANCE OF SHOWERS OR
ISOLATED THUNDERSTORMS. AN UPPER LEVEL RIDGE WILL BUILD INTO THE
AREA WEDNESDAY THROUGH THE REMAINDER OF THE WORK WEEK...RESULTING IN
ABOVE NORMAL TEMPERATURES THROUGH FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM TUESDAY...
OVERVIEW:
IN THE UPPER LEVELS...WESTERLY FLOW ALOFT WILL PREVAIL THROUGH
TONIGHT OVER THE CAROLINAS AND MID-ATLANTIC. AN UPPER LEVEL
DISTURBANCE THAT EMANATED FROM CONVECTION ALONG THE CENTRAL GULF
COAST YESTERDAY MORNING AND THAT PROGRESSED THROUGH CENTRAL NC
OVERNIGHT WAS LOCATED IN THE EASTERN CAROLINAS THIS MORNING...AND
WILL PROGRESS OFFSHORE BY NOON. AN H3 SHORTWAVE WAS NOTED IN CENTRAL
TN AT 15Z THIS MORNING...WITH ADDITIONAL SHORTWAVE ENERGY SLIGHTLY
UPSTREAM OVER ARKANSAS AND NORTHERN MS. THE LATEST RUC INDICATES THE
CENTRAL TN SHORTWAVE WILL PROGRESS INTO THE WEST/NW PIEDMONT BETWEEN
18-21Z...AND THE AR/MS SHORTWAVE WILL PROGRESS THROUGH NORTHERN
AL/GA INTO UPSTATE SC BY 21Z. THESE FEATURES ARE PROGGED TO INTERACT
TO SOME DEGREE...PROGRESSING THROUGH CENTRAL NC TO THE COAST BY OR
SHORTLY AFTER 00-03Z THIS EVENING. IN THE LOWER LEVELS...THE
OFFSHORE RIDGE WILL CONTINUE TO WEAKEN...WITH H85 FLOW VEERING FROM
SOUTHWESTERLY TO WESTERLY BY 00Z...THEN NORTHWEST OVERNIGHT AS A
WEAK H85 TROUGH PROGRESSES THROUGH THE MID-ATLANTIC/CAROLINAS.
TODAY:
SHOWER ACTIVITY PROGRESSING EASTWARD THROUGH THE AREA AT ~25 MPH
THIS MORNING IS LIKELY BEING FORCED BY THE UPPER LEVEL DISTURBANCE
THAT PUSHED INTO THE AREA FROM THE SOUTHWEST LAST NIGHT AND WHICH IS
CURRENTLY PROGRESSING INTO EASTERN NC. SHOWER ACTIVITY SHOULD
CONTINUE TO WANE AS THE AFOREMENTIONED DISTURBANCE TRACKS EAST AWAY
FROM CENTRAL NC...AND WILL INDICATE PRECIP CHANCES LOWERING AND
ENDING FROM WEST-EAST THROUGH 16-18Z. POCKETS OF SUNSHINE WERE NOTED
ON VIS SAT IMAGERY IN THE WAKE OF SHOWER ACTIVITY WEST OF HWY 1 AT
15Z...ALTHOUGH LOW STRATUS (CEILINGS ~1000-1500 FT AGL) HAS RECENTLY
DEVELOPED/EXPANDED UPSTREAM ALONG THE I-77 CORRIDOR AND MAY HELP
LIMIT HEATING THROUGH NOON IN THE WESTERN PIEDMONT BEFORE
STRENGTHENING INSOLATION/MIXING HELP SCATTER IT OUT TO SOME DEGREE.
AT THE VERY LEAST EXPECT POCKETS OF HEATING ACROSS THE AREA THIS
AFTERNOON...MORE-SO IN THE WESTERN PIEDMONT ASSUMING THE
AFOREMENTIONED STRATUS DOES NOT LINGER LONGER THAN EXPECTED.
W/REGARD TO INSTABILITY...SFC DEWPOINTS (MID/UPPER 50S) SHOULD BE
RELATIVELY UNIFORM ACROSS THE AREA THIS AFTERNOON...ALTHOUGH TEMPS
ARE EXPECTED TO BE A FEW DEGREES WARMER AND MID-LEVEL LAPSE RATES
ARE PROGGED TO BE ~1C STEEPER IN W/NW PORTIONS OF THE AREA. AS A
RESULT...THE RELATIVE BEST INSTABILITY THIS AFTERNOON SHOULD BE IN
THE WEST/NW PIEDMONT...WHERE 500-1000 J/KG OF MLCAPE COULD BE
PRESENT. FURTHER EAST...MLCAPE VALUES MAY BE LIMITED TO ~500 J/KG.
W/REGARD TO FORCING...THE SHORTWAVE PROGRESSING INTO EASTERN TN AND
THE OTHER SHORTWAVE PROGRESSING INTO NORTHERN AL AT 15Z THIS MORNING
WILL PROGRESS INTO THE CAROLINAS THIS AFTERNOON. ALTHOUGH LOWER
LEVEL FORCING WILL BE LARGELY ABSENT TODAY...THE AFOREMENTIONED
UPPER WAVES SHOULD PROVIDE SUFFICIENT ASCENT FOR AT LEAST ISOLD
CONVECTION TO DEVELOP IN THE PRESENCE OF MARGINAL INSTABILITY AND
FAVORABLE DIURNAL TIMING. THE 00/06Z HIGH-RES WRF/NMM MODELS DO NOT
ADD MUCH CONFIDENCE TO THE CONVECTIVE FCST...SHOWING A VARIETY OF
SOLUTIONS THAT DIFFER BOTH IN COVERAGE AND IN TIME. WITH THE ABOVE
IN MIND...WILL KEEP THE PRECIP FORECAST AS IS...INDICATING A 30%
CHANCE OF SHOWERS/STORMS THROUGH 00Z...THOUGH IT IS POSSIBLE ISOLD
CONVECTION (SHOULD IT DEVELOP) COULD PERSIST INTO THE 00-03Z TIME
FRAME EAST OF HWY 1. GIVEN RELATIVELY HOMOGENEOUS THICKNESSES ACROSS
THE AREA...HIGHS WILL BE DICTATED PRIMARILY BY CLOUD COVER. EXPECT
HIGHS RANGING FROM THE MID 70S (~75F) WEST OF HWY 1 TO LOWER 70S
EAST OF I-95.
SEVERE THREAT:
0-6KM BULK SHEAR VALUES TODAY ARE PROGGED TO BE 20-25 KT OR LESS. AS
A RESULT...EVEN IF CONVECTION DEVELOPS THIS AFTERNOON...BULK SHEAR
VALUES WILL ONLY BE MARGINALLY SUPPORTIVE OF MULTICELLULAR
ORGANIZATION. ADDITIONALLY...THE MIXED LAYER SHOULD BE RELATIVELY
SHALLOW TODAY...WITH LITTLE DCAPE/EVAP COOLING POTENTIAL...NOT TO
MENTION LOW/MID LEVEL FLOW (SFC-10 KFT) WILL BE NO MORE THAN 15-25
KT. WITH THE ABOVE IN MIND...DO NOT ANTICIPATE ANY SEVERE THREAT.
TONIGHT:
A MUCH DRIER MID/UPPER LEVEL AIRMASS WILL ADVECT INTO THE AREA VIA
WESTERLY FLOW ALOFT AFTER 00Z THIS EVENING...AND THIS SHOULD ALLOW
FOR A FAIR AMOUNT OF CLEARING FROM WEST-EAST BETWEEN 00-06Z. GIVEN
EXPECTED CLEARING AND THE PRESENCE OF A WEAK/BAGGY MSLP GRADIENT...
RADIATIONAL COOLING SHOULD ALLOW A NOCTURNAL INVERSION TO DEVELOP
WITHIN A FEW HRS AFTER SUNSET. DESPITE ADDITIONAL H3 SHORTWAVE
ENERGY EXPECTED TO DIG INTO THE AREA FROM THE N/NW OVERNIGHT...THE
COMBINATION OF DRY MID/UPPER LEVELS AND NOCTURNAL STABILIZATION WILL
PRECLUDE THE POTENTIAL FOR ANY PRECIPITATION. GIVEN NO REAL AIRMASS
CHANGE (STAGNANT GRADIENT)...EXPECT LOWS SIMILAR TO LAST NIGHT...IN
THE LOWER/MID 50S...WARMEST EAST/SE. GIVEN CALM WINDS AND RESIDUAL
BOUNDARY LAYER MOISTURE...AS LONG AS SKIES CLEAR AS EXPECTED...
WIDESPREAD FOG IS A GOOD BET TONIGHT. AREAS OF DENSE FOG OR EVEN
WIDESPREAD DENSE FOG WILL BE POSSIBLE...AND A DENSE FOG ADVISORY MAY
BE NEEDED LATE TONIGHT/WED MORNING. -VINCENT
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...
THE UPPER LEVEL RIDGE WILL BEGIN TO AMPLIFY WEDNESDAY WHILE THE
850MB HIGH BEGINS TO STRENGTHEN OVER THE SOUTHEAST US. DRY
ADIABATIC MIXING TO 850MB...WHICH SEEMS POSSIBLE WITH THE 850MB HIGH
STILL TO THE SOUTHWEST AND NORTHWESTERLY FLOW OVER THE CWA...YIELDS
HIGHS IN THE LOWER 80S. STATISTICAL GUIDANCE HAS BEEN INCHING IN
THIS DIRECTION ALSO...SO THERE IS FAIRLY GOOD CONFIDENCE THAT MOST
LOCATIONS WILL REACH 80 DEGREES. WILL FORECAST 79-82 WITH WARMEST
READINGS IN THE SOUTHEAST. -BLS
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT: CONTINUED DRY AND VERY
WARM. THE MID LEVEL LOW OVER SOUTHERN QUEBEC WEDNESDAY EVENING
CROSSES NEW ENGLAND AND MOVES TO JUST OFF THE CANADIAN MARITIMES BY
THURSDAY NIGHT. AS THIS LOW AND ASSOCIATED MID LEVEL TROUGH MOVE TO
OUR NORTHEAST... A MID LEVEL RIDGE AXIS SHIFTS EASTWARD OVER NC
WEDNESDAY NIGHT/THURSDAY... ENSURING CONTINUED DRY AND SINKING AIR
IN THE MID-UPPER LEVELS. THE SURFACE BACKDOOR FRONT ASSOCIATED WITH
THIS NEW ENGLAND LOW IS EXPECTED TO MOVE NO FURTHER SOUTHEAST THAN
NORTHEAST VA... WHICH WILL KEEP NC WITHIN A LIGHT/VARIABLE SURFACE
REGIME BECOMING SOUTHERLY THURSDAY. AFTER POCKETS OF DAYBREAK FOG
THURSDAY MORNING THAT SHOULD EASILY MIX OUT BY MID MORNING... THE
WEAK WARM AIR ADVECTION AND LACK OF CLOUDS ALOFT WILL ALLOW FOR
STRONG HEATING AS THICKNESSES REMAIN (AS MODELS HAVE INDICATED FOR
SEVERAL DAYS NOW) 40-50 METERS ABOVE NORMAL. LOWS 50-55 AND HIGHS
78-82. THE MID LEVEL RIDGE AXIS DROPS TO OUR SOUTHEAST THURSDAY
NIGHT AS A WEAK SOUTHERN STREAM WAVE MOVES ACROSS KY AND THE OH
VALLEY TOWARD THE CENTRAL/SRN APPALACHIANS. SLOWLY INCREASING
925-850 MB WINDS FROM WEST TO EAST ACROSS WV/VA WILL HELP SHARPEN
THE LEE TROUGH OVERNIGHT... AND THIS INCREASING LOW LEVEL MASS
CONVERGENCE AND APPROACH OF THE MID LEVEL WAVE WILL LEAD TO SKIES
BECOMING PARTLY TO MOSTLY CLOUDY WEST TO EAST. LOWS THURSDAY NIGHT
54-58 WITH ANOTHER ROUND OF PATCHY GROUND FOG POSSIBLE TOWARD DAWN.
-GIH
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 110 PM TUESDAY...
SURFACE HIGH PRESSURE ORIENTED WEST-EAST ACROSS THE NORTHERN GULF
RETREATS EAST INTO THE ATLANTIC WITH INCREASING MOISTURE RETURN INTO
THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS THURSDAY INTO FRIDAY.
INITIALLY THE BUILDING MID LEVEL RIDGE OVER THE EASTERN CONUS WILL
BLOCK THIS MOISTURE AND A VERY WARM DAY IS ON TAP THURSDAY.
THICKNESSES AND MOS GUIDANCE HAVE TRENDED UPWARDS...WITH LOW 80S NOW
WIDESPREAD AND NEAR RECORD MID 80S NOT OUT OF THE QUESTION. LOW
LEVEL MOISTURE WILL BE ON THE INCREASE THURSDAY NIGHT AS THE SURFACE
HIGH MOVES EAST ALLOWING MORE SOUTH TO SOUTHWEST FLOW. IN
ADDITION...AN UPPER WAVE MOVES ACROSS THE RIDGE AND A WEAK BACK DOOR
FRONT WILL BE SAGGING SOUTH INTO THE MID ATLANTIC. COULD SEE SOME
PATCHY LIGHT RAIN IN THE WEST LATE THURSDAY NIGHT...OTHERWISE
BECOMING MOSTLY CLOUDY AND MILD WITH LOWS IN THE MID 50S.
LONG-TERM GUIDANCE TRENDS SHOW A TENDENCY TO BE FARTHER WEST WITH
THE RIDGE AXIS ALOFT...WITH LOWER HEIGHTS OFFSHORE OVER THE WESTERN
ATLANTIC. THE ECMWF HAS TRENDED STRONGEST WITH UPPER-LEVEL LOW
PRESSURE MOVING OVER THE BROAD UPPER RIDGE...WHICH IN TURN PUSHES A
STRONGER COLD FRONT FROM THE NORTH THROUGH CENTRAL NORTH CAROLINA
EARLY IN THIS LONG-TERM PERIOD. THE GFS AND CANADIAN TREND WEAKER
AND GENERALLY SLOWER...AND THOUGH THE GFS HAS TRENDED LOWER WITH ITS
HEIGHTS ALOFT OFFSHORE...FRONTAL CONVERGENCE STILL APPEARS WEAKER
WITH WEAKER MID- AND UPPER-LEVEL FORCING THAT LINGERS LONGER INTO
THE WEEKEND.
GFSX MOS ENSEMBLE CHANCES FOR PRECIPITATION ARE CONSISTENTLY ABOVE
CLIMATOLOGY FRIDAY INTO SATURDAY...AND EVEN INTO SUNDAY...
DIMINISHING BY MONDAY AS DRIER AIR SHOULD GRADUALLY MOVE INTO
CENTRAL NORTH CAROLINA FROM THE NORTH AND NORTHEAST BEHIND ANY
SURFACE BOUNDARY. THE PATTERN OF DIMINISHING 850MB THETA-E FROM THE
NORTHEAST ON THE ECMWF DURING THE LATER PART OF THE WEEKEND APPEARS
REASONABLE...WITH MAINLY THE TIMING IN QUESTION. WILL FOCUS CHANCES
FOR SHOWERS HIGHER IN THE WESTERN PIEDMONT AND TOWARD THE VIRGINIA
BORDER FRIDAY NIGHT...WITH HIGHER CHANCES TRANSITIONING SOUTH
SATURDAY AND SATURDAY NIGHT AS THE SURFACE BOUNDARY MOVES SOUTH AND
MORE STABLE AIR GRADUALLY MOVES IN FROM THE NORTH. GIVEN SURFACE
RIDGING OVER THE SOUTHEAST STATES INTO THE EASTERN GULF...DO NOT
EXPECT ANY PERIOD TO BE A WASHOUT...WITH SCATTERED SHOWERS OR
PERIODS OF SHOWERS PRIMARILY EXPECTED. ABNORMALLY WARM THICKNESSES
AND COOLING ALOFT WITH TROUGHING COULD LEAD TO STEEP ENOUGH LAPSE
RATES TO PROVIDE FOR THUNDER...AS NOTED ON COARSE ECMWF MODEL
SOUNDINGS.
COOLER AIR WILL BE IN PLACE TUESDAY BUT THERE ARE CONSIDERABLE
DIFFERENCES IN MODELS CONCERNING SMALLER SCALE DETAILS WHICH WILL
DETERMINE SKY COVER AND THE POSSIBLITY OF SHOWERS IN THE
EAST...WHICH WILL BE NEARER IN PROXIMITY TO AN UPPER LOW OFFSHORE.
WILL HAVE A DRY FORECAST WITH A LOW PERCENTAGE OF CLOUD COVER
LEADING TO HIGHS IN THE MID 70S.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 730 AM TUESDAY...
PATCHES OF LIGHT RAIN ARE MOVING ACROSS CENTRAL NC THIS MORNING AS A
SERIES OF UPPER LEVEL DISTURBANCES DRIFT ACROSS THE AREA.
CEILINGS..HOWEVER..HAVE YET TO FALL BELOW 3K FT...AND OUTSIDE OF A
HEAVIER SHOWER THIS MORNING...CEILINGS SHOULD REMAIN VFR AS HEATING
AND WEAK MIXING COMMENCE. THERE IS QUITE A BIT OF UNCERTAINTY AS TO
HOW PRECIP WILL EVOLVE TODAY...AND THUS THERE IS LOW CONFIDENCE IN
TIMING AND IMPACT AT INDIVIDUAL TERMINALS. IN GENERAL.. CEILINGS
AND VSBYS SHOULD REMAIN IN THE 2500 TO 4000FT RANGE. THE LAST OF
THE AFOREMENTIONED UPPER DISTURBANCES SHOULD CROSS THE AREA BETWEEN
15Z AND 21Z...DURING WHICH TIME THERE WILL BE A CHANCE OF ANOTHER
ROUND OF SHOWERS OR AN ISOLATED THUNDERSTORM. ALL SHOWERS/STORMS
ARE EXPECTED TO BE EAST OF KFAY/KRWI BY 21Z-00Z.
SKIES WILL CLEAR TONIGHT AND WEST-NORTHWESTERLY WINDS ARE FORECAST
TO BE LIGHT. LOW LEVEL MOISTURE WILL REMAIN HIGH HOWEVER...WHICH
SHOULD LEAD TO A GOOD CHANCE OF FOG AT ALL TERMINALS. CONFIDENCE IN
FOG DEVELOPMENT IS HIGHEST AT KRDU/KRWI/KFAY...WHERE GUIDANCE SHOWS
FOG DEVELOPING JUST AFTER MIDNIGHT.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED TO PREVAIL EACH DAY...BUT A PERIOD OF
FOG/STRATUS IS POSSIBLE DURING THE MORNING HOURS. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE FRIDAY AFTERNOON INTO SATURDAY DUE
TO AN UPPER-LEVEL DISTURBANCE AND WEAK SURFACE LOW PRESSURE MOVING
THROUGH THE AREA.
&&
.CLIMATE...
HERE ARE UPCOMING HIGH TEMPERATURES RECORDS...
AT RDU:
03/14: 86 IN 1990
03/15: 87 IN 1973
03/16: 86 IN 1945
AT GSO:
03/14: 82 IN 1990
03/15: 87 IN 1967
03/16: 85 IN 1945
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...SMITH/HARTFIELD
LONG TERM...DJF/MLM
AVIATION...SMITH
CLIMATE...HARTFIELD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
144 PM EDT TUE MAR 13 2012
.SYNOPSIS...
SUBTROPICAL HIGH PRESSURE WILL BE IN CONTROL OF OUR WEATHER THROUGH
NEXT WEEKEND PROVIDING MUCH ABOVE NORMAL TEMPERATURES. AN INCREASE
IN MOISTURE WITH A FEW MINOR DISTURBANCES WILL RESULT IN AFTERNOON
AND EVENING SHOWERS AND THUNDERSTORMS AT THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM...A CHANNELED VORTMAX WAS ANALYZED ON THE WATER VAPOR
AND RUC 500MB SFC OVR CENTRAL TN...TRACKING THRU QUASI-ZONAL FLOW.
SCATTERED SHOWERS AND A COUPLE OF ISOLD TSTMS WERE BEING TRIGGERED
BY THE ASSOCIATED DPVA ACRS ERN TN/GA. THIS ACTIVITY LOOKS TO REMAIN
ISOLD AND PROBABLY ON A WEAKENING TREND AS IT ENTERS THE CWFA THIS
MORNING...AS SPC MESOANALYSIS SHOWS MUCAPES <500 J/KG IN THE
ENVIRONMENT THE CONVECTION IS MOVING. AS FOR CONVECTION THIS
AFTN...GUIDANCE STILL RATHER SUBDUED DESPITE DESTABILIZATION TO OVER
1500 J/KG AND THE VORTMAX STILL NOT THRU THE AREA BY PEAK HEATING.
ONLY THE 4 KM NCEP WRF HAS ANYTHING MORE THAN A STRAY STORM THIS
AFTN ACRS THE CWFA. BUT I AM GOING TO LEAVE THE LOW-END
CHC/SCATTERED WORDING FOR THE PIEDMONT DUE TO THE TIMING OF THE
VORTMAX FOR NOW. OTHERWISE...ONLY MINOR TWEAKS WERE MADE FOR THE
TODAY PERIOD.
PREVIOUS DISCUSSION...
AT 3 AM EDT TUESDAY...AN UPPER TROUGH AXIS WILL PROGRESS FROM THE OH
AND TN VALLEYS TO THE APPALACHIANS TODAY. A SHORTWAVE MOVING THROUGH
THIS TROUGH WILL CROSS OUR AREA AT MIDDAY. MOISTURE AHEAD OF THE
REMNANTS OF A FRONT WILL CONTINUE TO SUPPORT SHOWERS ACROSS OUR AREA
TODAY...BUT WITH LESS COVERAGE THAN BEFORE AS VEERING LOW LEVEL FLOW
LEADS TO LESS OF AN UPSLOPE COMPONENT AND WEAKER ISENTROPIC UPGLIDE.
FORECAST MAXIMUM TEMPERATURES WILL BE WELL ABOVE NORMAL TODAY IN
WARM ADVECTION...AND MODEL CAPE IS QUITE HIGH DURING PEAK HEATING...
WITH THE NAM SHOWING ALMOST 3000 J/KG IN UPSTATE SC...AND THE GFS
2000 J/KG IN NE GA. WITH MODEST SPEED AND DIRECTIONAL SHEAR...SOME
THUNDERSTORMS COULD BE STRONG. DRIER AIR ALOFT AND LOW WET BULB
ZEROS COULD SUPPORT HAIL AND GUSTY WINDS IN THE STRONGER STORMS.
BY THIS EVENING VEERING FLOW ALOFT WILL LEAD TO DRYING FROM THE
WEST...ENDING THE CHANCE OF PRECIPITATION. AFTER MIDNIGHT WINDS
SHIFT TO NW AT THE SURFACE AS THE REMNANTS OF THE FRONT MOVE BY.
MINIMUM TEMPERATURES WILL BE WELL ABOVE NORMAL AS HEIGHTS RISE WITH
THE PROGRESSION OF THE UPPER TROUGH...AND A LIGHT DOWNSLOPE FLOW
ENSUES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 230 AM EDT TUE...AN UPPER LEVEL RIDGE WILL REMAIN DOMINANT
ACROSS THE EAST THROUGH THE SHORT TERM PERIOD. ANY ISOLATED
CONVECTION UNDER THE RIDGE LATE WED AFTN SHOULD BE LIMITED TO A FEW
MTN RIDGETOP LOCATIONS WHERE UPSLOPE FLOW AND DIFFERENTIAL HEATING
CAN PROVIDE SOME WEAK TRIGGERING. THE MAIN STORY WILL BE WARM
TEMPERATURES...WITH 70S IN THE MTNS AT ALL BUT THE HIGHEST
ELEVATIONS...AND LOWER 80S ACROSS MOST OF THE FOOTHILLS AND
PIEDMONT. THIS SHOULD FALL A DEGREE OR TWO SHORT OF THE RECORDS AT
GSP/84...AND CLT/82.
MTN CONVECTIVE COVERAGE MAY BE JUST A BIT BETTER ON THU AFTN AS LOW
LEVEL CONVERGENCE IN THE WIND FIELD IMPROVES SLIGHTLY.
HOWEVER...DEEP LAYER CAPE SHOULD CONTINUE TO BE RATHER LIMITED AS
MID LEVEL TEMPS WARM FURTHER UNDER THE BUILDING RIDGE. MAX TEMPS
WILL BE COMPARABLE TO A DEGREE WARMER THAN WED. A WEAK WAVE MAY TOP
THE RIDGE THU NIGHT...BUT WITH THE MAIN MOISTURE AND FORCING PASSING
NORTH OF THE REGION THROUGH THE EARLY MORNING HOURS. WILL KEEP SCHC
TO CHC SHOWERS GOING MAINLY IN THE WRN/NRN MTNS FOR THE NIGHTTIME
PERIOD.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AT 230 AM TUESDAY...BOTH THE GFS AND THE ECMWF ARE IN GOOD AGREEMENT
THROUGH THE EXTENDED FORECAST PERIOD. A BROAD UPPER LEVEL RIDGE OF
HIGH PRESSURE WILL PERSIST OVER THE SOUTHEAST...WITH A SERIES OF
SHORTWAVES ORIGINATING IN THE SOUTHERN STREAM MOVING OVER THE RIDGE
ON FRIDAY AND SATURDAY. THE UPPER RIDGING WILL AMPLIFY SIGNIFICANTLY
SUNDAY INTO EARLY NEXT WEEK.
FRIDAY AND SATURDAY...A BROAD SUBTROPICAL HIGH OVER THE SOUTHEAST
U.S. WILL SLOWLY SHIFT EAST AND HEIGHTS WILL BE LOWERED. THIS WILL
ALLOW A SERIES OF WEAK SHORTWAVES OVER THE MISSISSIPPI VALLEYS TO
MOVE NE ACROSS OUR FORECAST AREA DURING THE PERIOD. THE LATEST
FORECAST SOUNDINGS CONTINUE TO INDICATE THAT PRECIPITABLE WATER
VALUES WILL RANGE FROM 1 TO 1.20 INCHES AND LIFTED INDEX VALUES WILL
BE AS LOW AS -4. ALSO...AFTERNOON SURFACE BASED CAPE VALUES WILL BE
IN THE 700 TO 1500 J/KG RANGE OVER MUCH OF OUR CWA. A COMBINATION OF
DECENT DIURNAL INSTABILITY...UPPER DYNAMICS AND DEEP MOISTURE ALOFT
WILL SUPPORT FOR THE DEVELOPMENT OF THUNDERSTORMS. HOWEVER...THE
DEGREE OF INSTABILITY AND UPPER LEVEL SYNOPTIC SCALE FORCING REMAIN
A BIT UNCERTAIN. SO I WILL CONTINUE TO CARRY 30S AND 40S POPS IN THE
AFTERNOON/EVENING HOURS. SUNDAY AND MONDAY...RATHER DRIER CONDITIONS
ARE EXPECTED AS THE UPPER RIDGING SIGNIFICANTLY AMPLIFIES OVER THE
REGION. TEMPERATURES UNDER THE RIDGE WILL BE 1O TO 15 DEGREES ABOVE
NORMAL THROUGH THE FORECAST PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT AND ELSEWHERE...STRATUS IS FINALLY LIFTING AND SCATTERING
OUT ACRS THE AREA EARLY THIS AFTN...BUT SOME LINGERING MVFR CIGS
POSSIBLE FOR NEXT HOUR OR SO OVER THE UPSTATE AND KCLT.
OTHERWISE...THE TRENDS ON SATELLITE AND RADAR SEEM TO LINE UP WITH
GUIDANCE WHICH INDICATES ANY CONVECTION THAT DEVELOPS THIS AFTN WILL
PROBABLY BE FAIRLY ISOLATED. SO NO MENTION WILL BE CARRIED IN ANY OF
THE TAF SITES. SKIES GENERALLY CLEAR OUT THIS EVENING...AND GUIDANCE
IS TRENDING MORE PESSIMISTIC WITH FOG DEVELOPMENT EARLY WEDNESDAY
MORNING. SO HAVE GONE A LITTLE LOWER ON VSBY RESTRICTIONS STARTING
AROUND 08-10Z...THEN BURNING OFF QUICKLY BY 14Z.
OUTLOOK...A FEW ISOLD SHRA/TSRA IN THE MTNS WED AND THU AFTNS...WITH
MORNING FOG POSSIBLE IN MOUNTAIN VALLEYS. GREATER COVERAGE OF
SHRA/TSRA EXPECTED FRIDAY AFTN.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JOH
NEAR TERM...ARK/JAT
SHORT TERM...HG
LONG TERM...JOH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1252 PM CDT TUE MAR 13 2012
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY THROUGH WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE MOVING EAST OVER SOUTHERN ONTARIO EARLY THIS MORNING WHILE
WEAK HIGH PRESSURE IS SHIFTING INTO THE NORTHERN MISSISSIPPI
VALLEY. LOW CLOUDS ARE IN THE PROCESS OF EXITING NE WISCONSIN...AND
ONLY HIGH CIRRUS IS PUSHING ACROSS THE DAKOTAS UPSTREAM. LOW LEVELS
ARE QUITE DRY THERE...AND THIS DRY AIRMASS WILL MOVE INTO THE REGION
TODAY. FORECAST CONCERNS ARE RELATIVELY MINIMAL FOR THIS TIME OF
THE YEAR...AND INCLUDE MIN HUMIDITIES TODAY...AND TEMPERATURES TODAY
AND TOMORROW.
TODAY...SHORTWAVE TROUGH OVER SOUTHEAST ONTARIO WILL LIFT NE...WHILE
A SHEARED WAVE OVER THE ARROWHEAD MOVES EAST OVER LAKE SUPERIOR.
DESPITE THE SHORTWAVES ALOFT PASSING NEARBY...CYCLONIC FLOW AT THE
SURFACE WILL BE ABATING...WHILE A WEAK RIDGE AXIS SHIFTS INTO THE
REGION THIS AFTERNOON. DRIER AIR OVER THE NORTHERN PLAINS WILL BE
PUSHING ACROSS THE AREA EARLY THIS MORNING...AND THE MVFR STRATUS
WILL BE EXITING NE WISCONSIN BY 09Z OR SO. A VERY DRY AIRMASS WILL
THEN BE IN PLACE FOR THE REST OF THE DAY. THOUGH MIXING MAY ONLY
REACH TO AROUND 900MB...WINDS SHOULD ALLOW FOR DRY AIR ABOVE THE
INVERSION TO CRASH TO THE SURFACE...ESPECIALLY OVER NORTHERN AND FAR
NORTHEAST WISCONSIN WHERE THE GRADIENT WILL BE THE TIGHTEST. HAVE
LOWERED DEWPOINTS TO THE MID TEENS UP NORTH...WHICH GIVES RH/S IN
THE 20-25 PCT RANGE. BOTH THE NAM AND GFS AGREE THAT 925MB TEMPS
WILL RANGE FROM 5-10C ACROSS THE AREA...WHICH CORRESPONDS THE MOST
WITH THE BCCONSRAW AND ECMWBC...THAT GIVES HIGHS RANGING FROM THE
MID 50S NORTH TO MID 60S SOUTH.
TONIGHT...RIDGING WILL BE PASSING OVERHEAD ACROSS THE REGION. WILL
SEE CLEAR TO MOSTLY CLEAR SKIES WITH LIGHT WINDS IN THE EVENING
BECOMING SOUTHEASTERLY. AXIS OF LOW LEVEL MOISTURE WILL GET DRAWN
NORTHWARD INTO CENTRAL WISCONSIN LATE. WITH LOW LEVEL TEMPS ALSO
WARMING AND NO SIGNS OF STRATUS UPSTREAM...THINK POSSIBILITIES OF
LOW STRATUS IS RELATIVELY LOW. LOWS RANGING FROM THE MID 30S
NORTH...TO THE MID 40S SOUTH.
WEDNESDAY...STRONG SHORTWAVE TROUGH WILL BE LIFTING NE OVER CENTRAL
CANADA...WHILE ITS COLD FRONT SAGS INTO NORTHWEST WISCONSIN IN THE
AFTERNOON. AHEAD OF THE FRONT...SOUTHWEST WINDS WILL ADVECT A VERY
WARM AND RELATIVELY MOIST AIRMASS INTO THE REGION. SLIGHTLY BACKED
SE WINDS WILL KEEP FAR NE WISCONSIN A LITTLE COOLER THAN THE REST OF
THE STATE...AND WILL GO WITH HIGHS IN THE UPPER 60S NORTH TO THE
MIDDLE 70S SOUTH. TEMPS MAY STRUGGLE TO GET OUT OF THE 50S ALONG
THE LAKESHORE THOUGH. WEAK CONVERGENCE ALONG THE FRONT COMBINED
WITH A LACK OF UPPER SUPPORT SHOULD KEEP THE FRONT INACTIVE TOMORROW
AFTERNOON SO NO REAL SHOWER OR THUNDER THREAT FORESEEN.
.LONG TERM...WEDNESDAY NIGHT THRU MONDAY. MAIN FORECAST CONCERN IS
HOW HIGH TO GO WITH TEMPS...AND PINNING DOWN BEST CHANCE FOR
SHOWERS/STORMS.
SW FLOW ALOFT WILL CONTINUE THROUGH THE PERIOD...WITH NO COLD AIR
IN SIGHT. TEMPS ALOFT ACTUALLY DO NOT CHANGE MUCH...WITH ONLY A
SLIGHT RISE IN HEIGHTS THIS WEEKEND AND EARLY NEXT WEEK AS THE
UPPER RIDGE BUILDS NORTH INTO ONTARIO. EXPECT 60S FOR MOST
LOCATIONS...WITH SOME 70S POSSIBLE ACROSS CENTRAL WI AND THE FOX
VALLEY NEXT WEEK. SEVERAL RECORDS ARE LIKELY TO FALL. ONLY
EXCEPTION TO THE VERY MILD AIR WILL BE ALONG THE LAKESHORE...AS A
SE SURFACE FLOW OFF OF LAKE MICHIGAN WILL KEEP TEMPS IN THE UPPER
40S AND 50S THROUGH MOST OF THE PERIOD.
FIRST CHANCE FOR SHOWERS/ISO STORMS WILL BE WEDNESDAY NIGHT AS A
WEAK FRONTAL BOUNDARY CROSSES THE AREA. NOT MANY POSITIVES TO GET
SHOWER/STORM ACTIVITY GOING...AS SURFACE CONVERGENCE IS WEAK AND
VERY LITTLE IF ANY UPPER LEVEL SUPPORT...PLUS BETTER MOISTURE
FORECAST TO BE JUST SOUTH/WEST OF THE AREA. THERE WILL BE FAIRLY
STEEP MID-LEVEL LAPSE RATES...ESPECIALLY ACROSS EASTERN WI...SO
WILL CONTINUE WITH HIGHER POPS THERE...BUT KEPT THE CHANCES LOW.
PREVIOUS ECMWF SHOWED A SHORTWAVE OVER THE NORTHERN PLAINS
THURSDAY...AND TOOK THIS FEATURE OVER LAKE SUPERIOR THURSDAY
NIGHT. THIS WOULD HAVE BROUGHT A DECENT CHANCE FOR PRECIP ACROSS
THE NORTH...HOWEVER LATEST RUN AS WELL AS OTHER MODELS AND
ENSEMBLES HAVE RIDGING AND WITH NOT MUCH UPPER SUPPORT OR
MOISTURE...WILL LEAVE THURSDAY NIGHT DRY. IF THIS SHORTWAVE
MATERIALIZES AND SLOWS A LITTLE...PASSING OVER THE AREA ON
FRIDAY...WE COULD GET SOME ACTIVITY TO DEVELOP...BUT THINK THIS IS
UNLIKELY WITH THIS PATTERN. AS WE WORK INTO THIS WEEKEND AND
EARLY NEXT WEEK...TIMING BEST CHANCES FOR SHOWERS/STORMS WILL BE
DIFFICULT AS SYNOPTIC PATTERN DOES NOT SUPPORT PRECIP. MODELS SHOW
POTENTIAL FOR WEAK SHORTWAVES MOVING THROUGH THE PLAINS AND GREAT
LAKES IN THE SW FLOW ALOFT...WHICH WOULD BRING A CHANCE OF
SHOWERS/STORMS. AFTER COORDINATION WITH SURROUNDING OFFICES...WENT
DRY FRIDAY-TUESDAY AS NO PERIOD LOOKS MORE LIKELY THAN THE OTHER
FOR SMALL CHANCE POPS AND UPPER RIDGE BUILDS OVERHEAD. BETTER
CHANCE FOR WIDESPREAD ACTIVITY LOOKS TO ARRIVE MID TO LATE NEXT
WEEK AS CLOSED UPPER LOW EJECTS OUT INTO THE PLAINS.
&&
.AVIATION...EXPECT PATCHY MVFR OR ISOLATED IFR VSBYS IN FOG AROUND
SUNRISE. OTHERWISE...VFR CONDITIONS SHOULD PERSIST ACROSS THE
AREA THROUGHOUT THE TAF PERIOD.
MG
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1108 AM CDT TUE MAR 13 2012
.UPDATE...
CLEAR SKIES WITH DRY AIR AND A HIGH PRESSURE RIDGE MOVING OVERHEAD.
INCREASED TEMPS A DEGREE OR TWO ACROSS THE FORECAST AREA. FULL SUN
AND MIXING TO ALMOST 925 TEMPS OF 10 TO 12C THIS AFTERNOON SHOULD
ALLOW FOR PLENTY OF HEATING INTO THE MID 60S...UPPER 60S TOWARD
SOUTH CENTRAL WI. PRESSURE GRADIENT SHOULD REMAIN TIGHT ENOUGH IN
EASTERN FORECAST AREA TO KEEP OFFSHORE FLOW...SO NO LAKE BREEZE
EXPECTED UNTIL LATE THIS AFTERNOON...AFTER DAYTIME HIGHS ARE MET.
&&
.AVIATION/18Z TAFS/...
A HIGH PRESSURE RIDGE WILL PUSH INTO WISCONSIN LATE THIS AFTERNOON
AND EVENING. WITH DRY AIR IN PLACE...ONLY HIGH CLOUDS OVERHEAD TODAY.
FAIRLY STRONG PRESSURE GRADIENT ALONG THE LAKESHORE TODAY...SO
WESTERLY WINDS WILL DOMINATE. LAKE BREEZE NOT EXPECTED TO REACH MKE
UNTIL EARLY EVENING...AND WINDS WILL BE LIGHT BY THEN.
LIGHT WINDS TONIGHT AND INCREASING LOW LEVEL MOISTURE...SO THERE
COULD BE SOME PATCHY FOG OVERNIGHT...ESPECIALLY IN LOW LYING AREAS.
BREEZY AND VERY WARM ON WEDNESDAY WITH MAINLY CLEAR SKIES. A FRONT
WILL CROSS SOUTHERN WI WED EVENING...POSSIBLY BRINGING SOME SHOWERS
AND THUNDERSTORMS.
&&
.PREV DISCUSSION... /ISSUED 317 AM CDT TUE MAR 13 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH
SURFACE LOW NORTH OF LAKE HURON WILL PUSH EAST AS HIGH PRESSURE FROM
WESTERN MINNESOTA TO MISSOURI MOVES INTO WISCONSIN DURING THE LATE
AFTERNOON AND EARLY EVENING. THE WEST WINDS AROUND 28 KNOTS AT
1 THSD FT DIMINISH TO 15 KNOTS BEFORE LAPSE RATES STEEPEN TO 9.5
C/KM FROM 900 MB DURING THE EARLY AFTERNOON. THEREFORE ONLY A
NARROW WINDOW FOR GUSTS TO AROUND 20 TO 25 MPH AROUND NOON.
THINK THERE WILL BE A LAKE BREEZE IN THE AFTERNOON...ESPECIALLY LATE
AS THE SURFACE HIGH APPROACHES LAKE MICHIGAN. LOCAL 4KM MESO MODEL
KEEPS A WEST/NORTHWEST SURFACE FLOW THROUGH 18Z...THE FARTHEST THE
MODEL RUNS. HOWEVER THE HRRR DOES BEGIN TO BRING SOME ONSHORE WINDS
SOUTH OF MILWAUKEE. EXPECT LATER MESO RUNS WILL SHOW SOME LAKE
BREEZE DEVELOPMENT DURING THE AFTERNOON. EVEN SO...TEMPS WILL HAVE
WARMED QUITE A BIT BY THE TIME THE LAKE BREEZE WOULD PUSH
INLAND...SO WENT WITH MILD HIGH TEMPS ALL THE WAY TO THE
LAKESHORE...THEN FALLING DURING THE MID AFTERNOON.
850 MB WARM AIR ADVECTION BEGINS ESPECIALLY OVER SOUTH CENTRAL
WISCONSIN LATER IN THE AFTERNOON AND CONTINUING TONIGHT.
LACK OF MOISTURE SO LITTLE IN WAY OF ALTOCUMULUS CLOUDS EXPECTED.
DRY LOW LEVELS SO FEW IF ANY CUMULUS.
WARM AIR ADVECTION CONTINUES OVERNIGHT. 925/850 MB MOISTURE
INCREASES TOWARD SUNRISE...ESPECIALLY OVER SOUTH CENTRAL WISCONSIN
AS 850 MB WINDS INCREASE TO 35 KNOTS.
WEDNESDAY - CONFIDENCE...MEDIUM
BROAD ANTICYCLONIC UPPER FLOW WITH WARM SOUTHWEST WINDS BRINGING 925
TEMPS INTO THE 17-19C RANGE. THIS SUGGESTS TEMPS WELL INTO THE 70S
QUITE PLAUSIBLE. MOS GUIDANCE LOOKS TOO COLD AS DO THE 2 METER
TEMPS. BUFKIT MIXED SOUNDINGS LOOK MORE REASONABLE AND MATCHES UP
BETTER WITH 925 TEMP TECHNIQUE.
WEDNESDAY NIGHT - CONFIDENCE...MEDIUM
SURFACE FRONT PUSHES ACROSS SRN WI WITH A RELATIVELY WEAK VORT LOBE.
DECENT INSTABILITY ABOVE 700 MILLIBARS WITH INITIAL LOW LEVEL
NEGATIVE AREA ON SOUNDING...MORE PRONOUNCED ON GFS. BUT THE CAP DOES
ERODE SOME INTO THE OVERNIGHT HOURS. WONDERING WHAT TO MAKE OF THE
CONSENSUS OF MOS SHOWING DENSE FOG DEVELOPMENT. IF WE GET SOME
SHOWERS/STORMS...FLOW DOES BECOME BAGGY SO FOG POTENTIAL DOES HAVE
SOME MERIT.
THURSDAY - CONFIDENCE...MEDIUM
EAST/WEST BOUNDARY LINGERS NEAR SRN WI. BULK OF MODELS SUGGEST QPF
IN THE SOUTHEAST CWA...IN LINE WITH GOING FORECAST. NAM SOUNDING
MUCH MORE ROBUST THAN THE GFS. NAM SHOWS CAPES OVER 1K WITH INVERTED
V LOOK TO SOUNDING. TEMPS HIGHLY DEPENDENT ON FRONTAL PLACEMENT AND
POTENTIAL FOR MORE LAKE INFLUENCE. 925 TEMPS STILL TOASTY. SO INLAND
AREAS THAT SEE SUN SHOULD MAKE THE 70S ONCE AGAIN.
FRIDAY THROUGH MONDAY - CONFIDENCE...LOW TO MEDIUM
CONSENSUS FROM SURROUNDING OFFICES IS TO GO WITH THE DRY LOOK RATHER
THAN THE SLIGHT POPS. UPPER RIDGE GRADUALLY BUILDS UP. APPEARS
FORCING WILL STAY WEST OF THE AREA CLOSER TO HIGHLY AMPLIFIED/SLOW
MOVING DEEP TROUGH. NOT A SLAM DUNK ON THIS AS MODELS SHOW A FEW
WEAK VORTS FLOATING BY HERE AND THERE BUT THINKING WAS TO JUST GO
DRY RATHER THAN HAVE SLIGHTS SPLASHED EVERYWHERE. UNSEASONABLE
WARMTH GOES ON AND ON.
AVIATION/12Z TAFS/...AFTER LINGERING PATCHES OF STRATOCUMULUS CLEARS
EARLY THIS MORNING ONLY FEW-SCATTERED CU EXPECTED WITH VFR CONDITIONS
EXPECTED THIS MORNING AND AFTERNOON AS HIGH PRESSURE PUSHES INTO
WISCONSIN LATE THIS AFTERNOON AND EVENING.
MARINE...WEST TO NORTHWEST WINDS WILL DIMINISH AS HIGH PRESSURE
PUSHES ACROSS LAKE MICHIGAN THIS EVENING. EXPECT A LAKE BREEZE TO
DEVELOP LATER THIS AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MRC
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
WEDNESDAY THROUGH MONDAY...COLLAR