Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/29/13
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
1207 PM CDT SAT APR 27 2013
.DISCUSSION...
UPDATED TO INCLUDE THE 18Z AVIATION DISCUSSION BELOW...
&&
.AVIATION...
WEAK SFC LOW PRESSURE WILL CONTINUE MOVING ACROSS THE STATE
THROUGH THIS AFTERNOON...WITH CHANCES FOR SHRA/TSRA PERSISTING FOR
MOST SITES THROUGH THE AFTERNOON HRS. MANY SITES HAVE CONTINUED
WITH MVFR TO LIFR CIGS/VIS THIS MORNING WHERE WINDS WERE LIGHT AND
WHERE PRECIP HAD BEEN OBSERVED. THE EXCEPTION BEING THE SRN SITES
WHERE RECENTLY VFR CONDITIONS HAD DEVELOPED AS RESULT OF STRONGER
SRLY WINDS AND LACK OF PRECIP. AFTER THIS SFC LOW EXITS THE STATE
TO THE EAST TONIGHT...WEST AND NW WINDS WILL BE SEEN...BUT REMAIN
FAIRLY LIGHT. AS A RESULT...WILL LIKELY SEE SOME FOG DEVELOP
DURING THE OVERNIGHT HRS...WITH IFR TO EVEN LIFR CONDITIONS
POSSIBLE. IMPROVING CONDITIONS WILL THEN BE SEEN LATER ON SUN.
&&
PREV DISCUSSION... /ISSUED 349 AM CDT SAT APR 27 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT
UNSETTLED CONDITIONS ARE EXPECTED FOR THE FIRST BACK OF THE
WEEKEND BUT THE SECOND HALF APPEARS TO BE MUCH BETTER AT THIS
POINT. GFS SOLUTION HAS BEEN THE MOST CONSISTENT MODEL OF LATE IN
THE SYNOPTIC SCALE AND SEE NO REAL REASON TO STRAY FROM IT AT THIS
POINT.
SHORTWAVE TROUGH...CLEARLY EVIDENT ON MOISTURE CHANNEL IMAGERY THIS
MORNING...EXTENDS FROM EASTERN KANSAS DOWN TO THE TEXAS PANHANDLE.
FEATURE IS EXPECTED TO MOVE TO THE EAST OVER THE NEXT 24 HOURS OR SO
WITH A WEAK H5 LOW DEVELOPING AS IT DOES. ON THE SURFACE...LATEST
ANALYSIS PLACES A WEAK WARM FRONT ALONG THE ARKANSAS/LOUISIANA
BORDER ANCHORED BY WEAK LOW PRESSURE ALONG THE RED RIVER. THIS
FEATURE APPEARS TO BE STARTING TO MOVE TOWARDS THE NORTH.
RADAR IMAGERY ACROSS THE REGION SHOWS ONGOING...SCATTERED SHOWER
ACTIVITY ACROSS THE STATE THAT IS LIKELY BEING GENERATED IN AN AREA
OF ASCENT ASSOCIATED WITH THE LOW LEVEL JET. CONVECTIVE COMPLEX
OVER EASTERN OKLAHOMA/WESTERN ARKANSAS HAS BEEN STEADILY WEAKENING
WITH TIME. THE AFOREMENTIONED TROUGH WILL PUSH SLOWLY EAST TODAY AS
FRONTAL SYSTEM LIFTS TO THE NORTH WITH WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY CONTINUING.
BEST CHANCES OF PRECIPITATION LOOK TO BE EARLY IN THE DAY WITH
CHANCES DECREASING DURING THE DAY AS SYSTEM LIFTS THROUGH. BEST
CHANCES WILL THEN BE CONFINED TO THE TRAILING COLD FRONT AND THERE
REMAINS A CHANCE OF SOME STRONGER CONVECTION OVER THE SOUTHEAST PART
OF THE STATE. WILL HOLD ONTO LINGERING PRECIPITATION CHANCES
EARLY ON SUNDAY BEFORE ENDING THE RAINFALL ENTIRELY.
QPF FORECASTS ALL OVER PLACE THIS MORNING BUT HRRR MODEL ACTUALLY
SEEMS TO HAVE THE BEST HANDLE ON THE SYSTEM. AS SUCH...WILL FOLLOW
ITS TRENDS CONCERNING PRECIPITATION COVERAGE AND WILL TRIM BACK THE
AMOUNTS. WILL BLEND ECMWF/MAV NUMBERS FOR TEMPERATURES.
REMAINDER OF THE SHORT TERM PERIOD LOOKS RATHER EVENTFUL AS SURFACE
HIGH PRESSURE MOVES ACROSS AND EVENTUALLY EAST OF THE FORECAST AREA.
SOUTHERLY SURFACE WINDS AND A RATHER NONDESCRIPT UPPER FLOW WILL
ALLOW TEMPERATURES TO GET ABOVE NORMALS FOR LATE APRIL/EARLY MAY.
NEXT SYSTEM WILL BEGIN TO DROP DOWN INTO THE CENTRAL PLAINS LATE BUT
ITS IMPACTS WILL LIKELY BE FELT IN THE EXTENDED PERIOD.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
AN UPPER TROUGH WILL BE OVER THE NORTHERN PLAINS TO BEGIN THE
PERIOD WITH A RIDGE OVER THE EASTERN U.S. THE UPPER TROUGH WILL
DEEPEN THROUGH THE SOUTHERN PLAINS WEDNESDAY NIGHT AND THURSDAY.
BY FRIDAY IT BECOMES A CLOSED LOW OVER THE OHIO RIVER VALLEY
PROVIDING NORTHWEST FLOW TO ARKANSAS.
A COLD FRONT WILL MOVE THROUGH ARKANSAS WEDNESDAY. MOISTURE WILL
STREAM NORTH OUT OF THE GULF OF MEXICO. CHANCES OF SHOWERS AND
THUNDERSTORMS WILL INCREASE THROUGH WEDNESDAY...REACH THEIR PEAK
WEDNESDAY NIGHT...AND END THURSDAY MORNING. HIGH PRESSURE WILL BUILD
OVER THE AREA THURSDAY AND FRIDAY. MUCH COOLER AND DRIER AIR WILL BE
USHERED IN WITH THIS COLD HIGH PRESSURE SYSTEM. ABOVE NORMAL
TEMPERATURES ARE EXPECTED WEDNESDAY AND MUCH BELOW NORMAL FOR
THURSDAY AND FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 70 52 72 52 / 80 40 20 10
CAMDEN AR 78 57 77 51 / 60 30 10 10
HARRISON AR 65 49 72 51 / 80 20 10 10
HOT SPRINGS AR 74 54 76 52 / 60 20 10 10
LITTLE ROCK AR 74 55 75 54 / 70 30 10 10
MONTICELLO AR 79 59 76 54 / 80 40 20 10
MOUNT IDA AR 73 52 76 51 / 60 20 10 10
MOUNTAIN HOME AR 66 50 72 51 / 80 30 10 10
NEWPORT AR 71 54 72 52 / 80 40 20 10
PINE BLUFF AR 77 57 76 54 / 70 40 20 10
RUSSELLVILLE AR 70 51 74 53 / 70 20 10 10
SEARCY AR 72 54 73 53 / 80 40 20 10
STUTTGART AR 75 56 75 54 / 80 40 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...62
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
652 AM CDT SAT APR 27 2013
.AVIATION...
LOW PRESSURE IS LOCATED NEAR THE TEXAS AND OKLAHOMA BORDER. THIS
WILL MOVE ALONG A WARM FRONT THIS MORNING AND WILL BRING A
TRAILING COLD FRONT ACROSS THE AREA THIS AFTERNOON. SHOWERS AND
THUNDERSTORMS WILL CONTINUE THROUGH MUCH OF THE DAY. RAIN CHANCES
WILL DECREASE THIS EVENING AND CEILINGS WILL RISE. PATCHY FOG WILL
DEVELOP OVERNIGHT. LIFR TO MVFR CONDITIONS ARE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT SAT APR 27 2013/
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
USETTLED CONDITIONS ARE EXPECTED FOR THE FIRST BACK OF THE WEEKEND
BUT THE SECOND HALF APPEARS TO BE MUCH BETTER AT THIS POINT. GFS
SOLUTION HAS BEEN THE MOST CONSISTENT MODEL OF LATE IN THE SYNOPTIC
SCALE AND SEE NO REAL REASON TO STRAY FROM IT AT THIS POINT.
SHORTWAVE TROUGH...CLEARLY EVIDENT ON MOISTURE CHANNEL IMAGERY THIS
MORNING...EXTENDS FROM EASTERN KANSAS DOWN TO THE TEXAS PANHANDLE.
FEATURE IS EXPECTED TO MOVE TO THE EAST OVER THE NEXT 24 HOURS OR SO
WITH A WEAK H5 LOW DEVELOPING AS IT DOES. ON THE SURFACE...LATEST
ANALYSIS PLACES A WEAK WARM FRONT ALONG THE ARKANSAS/LOUISIANA
BORDER ANCHORED BY WEAK LOW PRESSURE ALONG THE RED RIVER. THIS
FEATURE APPEARS TO BE STARTING TO MOVE TOWARDS THE NORTH.
RADAR IMAGERY ACROSS THE REGION SHOWS ONGOING...SCATTERED SHOWER
ACTIVITY ACROSS THE STATE THAT IS LIKELY BEING GENERATED IN AN AREA
OF ASCENT ASSOCIATED WITH THE LOW LEVEL JET. CONVECTIVE COMPLEX
OVER EASTERN OKLAHOMA/WESTERN ARKANSAS HAS BEEN STEADILY WEAKENING
WITH TIME. THE AFOREMENTIONED TROUGH WILL PUSH SLOWLY EAST TODAY AS
FRONTAL SYSTEM LIFTS TO THE NORTH WITH WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY CONTINUING.
BEST CHANCES OF PRECIPITATION LOOK TO BE EARLY IN THE DAY WITH
CHANCES DECREASING DURING THE DAY AS SYSTEM LIFTS THROUGH. BEST
CHANCES WILL THEN BE CONFINED TO THE TRAILING COLD FRONT AND THERE
REMAINS A CHANCE OF SOME STRONGER CONVECTION OVER THE SOUTHEAST PART
OF THE STATE. WILL HOLD ONTO LINGERING PRECIPITATION CHANCES
EARLY ON SUNDAY BEFORE ENDING THE RAINFALL ENTIRELY.
QPF FORECASTS ALL OVER PLACE THIS MORNING BUT HRRR MODEL ACTUALLY
SEEMS TO HAVE THE BEST HANDLE ON THE SYSTEM. AS SUCH...WILL FOLLOW
ITS TRENDS CONCERNING PRECIPITATION COVERAGE AND WILL TRIM BACK THE
AMOUNTS. WILL BLEND ECWMF/MAV NUMBERS FOR TEMPERATURES.
REMAINDER OF THE SHORT TERM PERIOD LOOKS RATHER EVENTFUL AS SURFACE
HIGH PRESSURE MOVES ACROSS AND EVENTUALLY EAST OF THE FORECAST AREA.
SOUTHERLY SURFACE WINDS AND A RATHER NONDESCRIPT UPPER FLOW WILL
ALLOW TEMPERATURES TO GET ABOVE NORMALS FOR LATE APRIL/EARLY MAY.
NEXT SYSTEM WILL BEGIN TO DROP DOWN INTO THE CENTRAL PLAINS LATE BUT
ITS IMPACTS WILL LIKELY BE FELT IN THE EXTENDED PERIOD.
LONG TERM...WEDNESDAY THROUGH FRIDAY...
AN UPPER TROUGH WILL BE OVER THE NORTHERN PLAINS TO BEGIN THE PERIOD
WITH A RIDGE OVER THE EASTERN U.S. THE UPPER TROUGH WILL DEEPEN
THROUGH THE SOUTHERN PLAINS WEDNESDAY NIGHT AND THURSDAY. BY FRIDAY
IT BECOMES A CLOSED LOW OVER THE OHIO RIVER VALLEY PROVIDING
NORTHWEST FLOW TO ARKANSAS.
A COLD FRONT WILL MOVE THROUGH ARKANSAS WEDNESDAY. MOISTURE WILL
STREAM NORTH OUT OF THE GULF OF MEXICO. CHANCES OF SHOWERS AND
THUNDERSTORMS WILL INCREASE THROUGH WEDNESDAY...REACH THEIR PEAK
WEDNESDAY NIGHT...AND END THURSDAY MORNING. HIGH PRESSURE WILL BUILD
OVER THE AREA THURSDAY AND FRIDAY. MUCH COOLER AND DRIER AIR WILL BE
USHERED IN WITH THIS COLD HIGH PRESSURE SYSTEM. ABOVE NORMAL
TEMPERATURES ARE EXPECTED WEDNESDAY AND MUCH BELOW NORMAL FOR
THURSDAY AND FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 70 52 72 52 / 70 40 20 10
CAMDEN AR 78 57 77 51 / 60 30 10 10
HARRISON AR 65 49 72 51 / 80 20 10 10
HOT SPRINGS AR 74 54 76 52 / 60 20 10 10
LITTLE ROCK AR 74 55 75 54 / 60 30 10 10
MONTICELLO AR 79 59 76 54 / 80 40 20 10
MOUNT IDA AR 73 52 76 51 / 60 20 10 10
MOUNTAIN HOME AR 66 50 72 51 / 80 30 10 10
NEWPORT AR 71 54 72 52 / 70 40 20 10
PINE BLUFF AR 77 57 76 54 / 70 40 20 10
RUSSELLVILLE AR 70 51 74 53 / 70 20 10 10
SEARCY AR 72 54 73 53 / 70 40 20 10
STUTTGART AR 75 56 75 54 / 70 40 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...51
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
349 AM CDT SAT APR 27 2013
..SHORT TERM...TODAY THROUGH TUESDAY NIGHT
USETTLED CONDITIONS ARE EXPECTED FOR THE FIRST BACK OF THE WEEKEND
BUT THE SECOND HALF APPEARS TO BE MUCH BETTER AT THIS POINT. GFS
SOLUTION HAS BEEN THE MOST CONSISTENT MODEL OF LATE IN THE SYNOPTIC
SCALE AND SEE NO REAL REASON TO STRAY FROM IT AT THIS POINT.
SHORTWAVE TROUGH...CLEARLY EVIDENT ON MOISTURE CHANNEL IMAGERY THIS
MORNING...EXTENDS FROM EASTERN KANSAS DOWN TO THE TEXAS PANHANDLE.
FEATURE IS EXPECTED TO MOVE TO THE EAST OVER THE NEXT 24 HOURS OR SO
WITH A WEAK H5 LOW DEVELOPING AS IT DOES. ON THE SURFACE...LATEST
ANALYSIS PLACES A WEAK WARM FRONT ALONG THE ARKANSAS/LOUISIANA
BORDER ANCHORED BY WEAK LOW PRESSURE ALONG THE RED RIVER. THIS
FEATURE APPEARS TO BE STARTING TO MOVE TOWARDS THE NORTH.
RADAR IMAGERY ACROSS THE REGION SHOWS ONGOING...SCATTERED SHOWER
ACTIVITY ACROSS THE STATE THAT IS LIKELY BEING GENERATED IN AN AREA
OF ASCENT ASSOCIATED WITH THE LOW LEVEL JET. CONVECTIVE COMPLEX
OVER EASTERN OKLAHOMA/WESTERN ARKANSAS HAS BEEN STEADILY WEAKENING
WITH TIME. THE AFOREMENTIONED TROUGH WILL PUSH SLOWLY EAST TODAY AS
FRONTAL SYSTEM LIFTS TO THE NORTH WITH WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY CONTINUING.
BEST CHANCES OF PRECIPITATION LOOK TO BE EARLY IN THE DAY WITH
CHANCES DECREASING DURING THE DAY AS SYSTEM LIFTS THROUGH. BEST
CHANCES WILL THEN BE CONFINED TO THE TRAILING COLD FRONT AND THERE
REMAINS A CHANCE OF SOME STRONGER CONVECTION OVER THE SOUTHEAST PART
OF THE STATE. WILL HOLD ONTO LINGERING PRECIPITATION CHANCES
EARLY ON SUNDAY BEFORE ENDING THE RAINFALL ENTIRELY.
QPF FORECASTS ALL OVER PLACE THIS MORNING BUT HRRR MODEL ACTUALLY
SEEMS TO HAVE THE BEST HANDLE ON THE SYSTEM. AS SUCH...WILL FOLLOW
ITS TRENDS CONCERNING PRECIPITATION COVERAGE AND WILL TRIM BACK THE
AMOUNTS. WILL BLEND ECWMF/MAV NUMBERS FOR TEMPERATURES.
REMAINDER OF THE SHORT TERM PERIOD LOOKS RATHER EVENTFUL AS SURFACE
HIGH PRESSURE MOVES ACROSS AND EVENTUALLY EAST OF THE FORECAST AREA.
SOUTHERLY SURFACE WINDS AND A RATHER NONDESCRIPT UPPER FLOW WILL
ALLOW TEMPERATURES TO GET ABOVE NORMALS FOR LATE APRIL/EARLY MAY.
NEXT SYSTEM WILL BEGIN TO DROP DOWN INTO THE CENTRAL PLAINS LATE BUT
ITS IMPACTS WILL LIKELY BE FELT IN THE EXTENDED PERIOD.
&&
.LONG TERM...WEDNESDAY THROUGH FRIDAY...
AN UPPER TROUGH WILL BE OVER THE NORTHERN PLAINS TO BEGIN THE PERIOD
WITH A RIDGE OVER THE EASTERN U.S. THE UPPER TROUGH WILL DEEPEN
THROUGH THE SOUTHERN PLAINS WEDNESDAY NIGHT AND THURSDAY. BY FRIDAY
IT BECOMES A CLOSED LOW OVER THE OHIO RIVER VALLEY PROVIDING
NORTHWEST FLOW TO ARKANSAS.
A COLD FRONT WILL MOVE THROUGH ARKANSAS WEDNESDAY. MOISTURE WILL
STREAM NORTH OUT OF THE GULF OF MEXICO. CHANCES OF SHOWERS AND
THUNDERSTORMS WILL INCREASE THROUGH WEDNESDAY...REACH THEIR PEAK
WEDNESDAY NIGHT...AND END THURSDAY MORNING. HIGH PRESSURE WILL BUILD
OVER THE AREA THURSDAY AND FRIDAY. MUCH COOLER AND DRIER AIR WILL BE
USHERED IN WITH THIS COLD HIGH PRESSURE SYSTEM. ABOVE NORMAL
TEMPERATURES ARE EXPECTED WEDNESDAY AND MUCH BELOW NORMAL FOR
THURSDAY AND FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 70 52 72 52 / 70 40 20 10
CAMDEN AR 78 57 77 51 / 60 30 10 10
HARRISON AR 65 49 72 51 / 80 20 10 10
HOT SPRINGS AR 74 54 76 52 / 60 20 10 10
LITTLE ROCK AR 74 55 75 54 / 60 30 10 10
MONTICELLO AR 79 59 76 54 / 80 40 20 10
MOUNT IDA AR 73 52 76 51 / 60 20 10 10
MOUNTAIN HOME AR 66 50 72 51 / 80 30 10 10
NEWPORT AR 71 54 72 52 / 70 40 20 10
PINE BLUFF AR 77 57 76 54 / 70 40 20 10
RUSSELLVILLE AR 70 51 74 53 / 70 20 10 10
SEARCY AR 72 54 73 53 / 70 40 20 10
STUTTGART AR 75 56 75 54 / 70 40 20 10 &
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...51 / LONG TERM...56
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
121 PM EDT SAT APR 27 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 326 AM EDT SAT APR 27 2013
SURFACE AND UPPER LOWS WILL MOVE THROUGH CENTRAL INDIANA THIS
WEEKEND BRINGING SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO THE
AREA. DRY WEATHER WILL THEN MOVE IN FOR MUCH OF THE EARLY PART OF
THE WORK WEEK...BUT A COLD FRONT WILL BRING RETURNING CHANCES FOR
RAIN FROM MID TO LATE WEEK NEXT WEEK.
TEMPERATURES WILL GRADUALLY WARM TO ABOVE AVERAGE BY MID WEEK...THEN
FALL TO BELOW AVERAGE BY THE END OF THE WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 1024 AM EDT SAT APR 27 2013
CLOUD SHIELD EXPANDING NORTH THIS MORNING WITH LARGE AREA OF RAIN
APPROACHING FROM THE SOUTHWEST. TEMPS HAD WARMED INTO THE 50S
ACROSS THE FORECAST AREA AT 14Z WITH WARMEST TEMPS OVER NORTHEAST
COUNTIES WHERE SKIES WERE MOSTLY SUNNY.
MAIN CHANGE FOR THE UPDATE IS TO DELAY ONSET OF THE RAINFALL BY
3-4 HOURS ACROSS MUCH OF THE FORECAST AREA LATER TODAY AS DRIER AIR
THROUGH THE LOW LEVELS REMAINS PRESENT. HAVE SEEN A FEW SPRINKLES
INTO THE LOWER WABASH VALLEY ALREADY THIS MORNING BUT MUCH OF THIS
ACTIVITY IS DIMINISHING A IT MOVES NORTHEAST AND RUNS INTO AN
INCREASING DRIER AIRMASS. CURRENT RAP INDICATING DEEPER ISENTROPIC
LIFT REALLY HOLDS OFF ACROSS CENTRAL INDIANA UNTIL AFTER 18Z AND
FOR THE NORTHERN HALF OF THE FORECAST AREA UNTIL BETWEEN 21Z AND
00Z. CONSIDERING THE DEPTH OF THE DRY AIR PRESENT...THE SURGE OF
ISENTROPIC LIFT WILL BE NEEDED TO SATURATE THE LOW LEVELS AND
ENABLE PRECIP SHIELD TO EXPAND NORTH. HAVE THEREFORE SLOWED DOWN
ARRIVAL OF RAINFALL BY A FEW HOURS...WITH MANY AREAS NORTH OF I-70
REMAINING DRY UNTIL AFTER 21-22Z. LEFT FORECAST HIGHS ALONE FOR
THE AFTERNOON WITH THE EXCEPTION OF THE FAR NORTHERN COUNTIES
WHERE SUNSHINE WILL CONTINUE FOR THE NEXT FEW HOURS AND MAY ENABLE
LOCATIONS LIKE KOKOMO AND MUNCIE TO MAKE A RUN AT 70 LATER TODAY.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 326 AM EDT SAT APR 27 2013
FOCUS CONTINUES TO BE ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS
ARE CLOSE ENOUGH THAT A BLEND CAN BE USED FOR MOST ITEMS.
Q-VECTOR FORECAST PLOTS SHOW THE FORCING MOVING INTO THE AREA
TONIGHT ASSOCIATED WITH AN UPPER LOW MOVING INTO THE AREA...SO
GRADUALLY INCREASED POPS ACROSS THE FORECAST AREA TONIGHT. WENT
CLOSE TO MOS POPS WITH LIKELY NORTH AND CATEGORICAL SOUTH.
ON SUNDAY THE SURFACE AND UPPER LOWS WILL MOVE THROUGH THE AREA. MOS
POPS ARE HIGH...BUT MODELS ARE ONLY SHOWING RELATIVELY WEAK FORCING.
FORECAST REFLECTIVITY ALSO SHOWS MORE OF A SCATTERED COVERAGE THAN
WIDESPREAD AT ANY ONE TIME. HOWEVER WITH THE LOWS MOVING THROUGH
CANNOT REALLY ARGUE AGAINST THE HIGH POPS SINCE MOST AREAS COULD SEE
A HUNDREDTH OF AN INCH IN A PASSING SHOWER. WITH THE HIGH POPS WILL
USE OCCASIONAL WORDING TO HIGHLIGHT DRY PERIODS DURING THE
DAY.
SOME INSTABILITY MOVES IN WITH THE SURFACE LOW SO MENTIONED ISOLATED
THUNDERSTORMS SUNDAY.
WENT LOW POPS SUNDAY EVENING AS MODELS CONTINUE TO HINT AT LINGERING
PRECIPITATION. FOR OVERNIGHT SUNDAY NIGHT INTO MONDAY WENT SLIGHT
CHANCE POPS ACROSS THE EAST FOR THE SAME REASON.
FOR TEMPERATURES THROUGH THE FIRST HALF OF THE PERIOD...GENERALLY
WENT WITH THE COOLER OF THE MOS DURING THE DAY AND THE WARMER OF THE
MOS DURING THE NIGHT DUE TO CLOUDS AND RAINFALL. GENERALLY STUCK
WITH A BLEND FOR THE SECOND HALF.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 300 AM EDT SAT APR 27 2013
MODEL TIMING DIFFERENCES REGARDING AN UPPER LOW AND UPSTREAM FRONTAL
SYSTEM WILL CONTINUE TO BE THE MAIN ISSUE IN THE EXTENDED ESPECIALLY
LATE WEEK.
THE 00Z GFS AND GEFS CONTINUE TO BE MUCH FASTER AND WEAKER WITH THE
AFOREMENTIONED UPPER SYSTEM. BY 00Z FRIDAY...THE 12Z ECMWF HAS A
DEEP UPPER LOW ACROSS NORTHEASTERN NEBRASKA...WHILE THE 00Z GFS AND
GEFS HAVE A WEAKER OPEN TROUGH ACROSS EASTERN MISSOURI AND FINALLY
THE 00Z GEM HAS AN UPPER LOW FORMING WITHIN THE TROUGH ACROSS
NORTHERN TEXAS. MEANWHILE...THE GFS AND GEFS WERE MUCH FASTER WITH
THE LEAD FRONT WITH THE ECMWF AND TO A LESSER EXTENT EURO LAGGING
WELL TO THE WEST. THE GEFS AND GFS HAVE THE FRONT ACROSS OHIO...THE
GEM ACROSS EASTERN INDIANA AND EURO ACROSS WESTERN INDIANA AT THAT
TIME. THIS RESULTS IN QUICKER MOISTURE RETURN AND QPF FROM THE GFS
AND GEFS. THE GFS AND GEFS HAS DECENT QPF BY WEDNESDAY NIGHT...WHILE
THE OTHER LONG RANGE MODELS HOLD OFF TIL WEDNESDAY.
WITH A STRONG RIDGING ACROSS THE EASTERN SEABOARD AS WELL AS THE
WEST...PREFER THE SLOWER ECMWF BUT WILL ALLOW FOR SMALL POPS OF THE
REGIONAL INITIALIZATION ON WEDNESDAY IN THE SMALL CHANCE THE GFS
VERIFIES OR THE EURO AND GEM SPEED UP A LITTLE BIT IN LATER RUNS.
ALL MODELS HAVE DECENT QPF ON THURSDAY AND HOLD ON TO IT ALSO FRIDAY
WHICH IS REFLECTED IN CONTINUED REGIONAL INITIALIZATION POPS.
AGAIN WITH LOW CONFIDENCE FROM MODEL DIFFERENCES...WILL ACCEPT THE
REGIONAL TEMPERATURES WHICH HAVE HIGHS IN THE 70S THROUGH WEDNESDAY
AND THEN PROGRESSIVELY COOLER NUMBERS IN THE 60S ON THURSDAY AND 50S
BY FRIDAY AS COLD FRONT SLIDES TO THE EAST.
&&
.AVIATION /DISCUSSION FOR THE 27/1800Z TAF ISSUANCE/...
ISSUED AT 112 PM EDT SAT APR 27 2013
DELAYED ONSET OF RAIN ACROSS TAF SITES THIS AFTERNOON WITH THE BULK OF
PRECIP NOT ENTERING UNTIL LATE AFTERNOON/EARLY EVENING AT KIND/KLAF/KBMG.
THE EXCEPTION WILL BE KHUF WHICH COULD SEE LIGHT RAIN WITHIN THE
NEXT 1 TO 2 HOURS. VFR CONDITIONS WILL PREVAIL UP UNTIL THAT POINT...
BUT CONDITIONS WILL QUICKLY FALL TO MVFR CATEGORY WITH ONSET OF
RAIN...AND CONTINUE TO DETERIORATE FURTHER TONIGHT AS CEILINGS
FALL AND FOG FORMS. IFR/LIFR CATEGORY WILL BE POSSIBLE AS EARLY AS
SUN 00Z. EXPECT MVFR CONDITIONS TO RETURN AROUND MID-MORNING
TOMORROW AT MOST TAF SITES AS RAIN TAPERS OFF. WINDS WILL BE
SOUTHEASTERLY FOR THE MAJORITY OF TAF PERIOD WITH SUSTAINED SPEEDS
OF 6 TO 12 KTS...AND THEN VEER TO THE SOUTHWEST LATE TOMORROW
MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1024 AM EDT SAT APR 27 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 326 AM EDT SAT APR 27 2013
SURFACE AND UPPER LOWS WILL MOVE THROUGH CENTRAL INDIANA THIS
WEEKEND BRINGING SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO THE
AREA. DRY WEATHER WILL THEN MOVE IN FOR MUCH OF THE EARLY PART OF
THE WORK WEEK...BUT A COLD FRONT WILL BRING RETURNING CHANCES FOR
RAIN FROM MID TO LATE WEEK NEXT WEEK.
TEMPERATURES WILL GRADUALLY WARM TO ABOVE AVERAGE BY MID WEEK...THEN
FALL TO BELOW AVERAGE BY THE END OF THE WEEK.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 1024 AM EDT SAT APR 27 2013
CLOUD SHIELD EXPANDING NORTH THIS MORNING WITH LARGE AREA OF RAIN
APPROACHING FROM THE SOUTHWEST. TEMPS HAD WARMED INTO THE 50S
ACROSS THE FORECAST AREA AT 14Z WITH WARMEST TEMPS OVER NORTHEAST
COUNTIES WHERE SKIES WERE MOSTLY SUNNY.
MAIN CHANGE FOR THE UPDATE IS TO DELAY ONSET OF THE RAINFALL BY
3-4 HOURS ACROSS MUCH OF THE FORECAST AREA LATER TODAY AS DRIER AIR
THROUGH THE LOW LEVELS REMAINS PRESENT. HAVE SEEN A FEW SPRINKLES
INTO THE LOWER WABASH VALLEY ALREADY THIS MORNING BUT MUCH OF THIS
ACTIVITY IS DIMINISHING A IT MOVES NORTHEAST AND RUNS INTO AN
INCREASING DRIER AIRMASS. CURRENT RAP INDICATING DEEPER ISENTROPIC
LIFT REALLY HOLDS OFF ACROSS CENTRAL INDIANA UNTIL AFTER 18Z AND
FOR THE NORTHERN HALF OF THE FORECAST AREA UNTIL BETWEEN 21Z AND
00Z. CONSIDERING THE DEPTH OF THE DRY AIR PRESENT...THE SURGE OF
ISENTROPIC LIFT WILL BE NEEDED TO SATURATE THE LOW LEVELS AND
ENABLE PRECIP SHIELD TO EXPAND NORTH. HAVE THEREFORE SLOWED DOWN
ARRIVAL OF RAINFALL BY A FEW HOURS...WITH MANY AREAS NORTH OF I-70
REMAINING DRY UNTIL AFTER 21-22Z. LEFT FORECAST HIGHS ALONE FOR
THE AFTERNOON WITH THE EXCEPTION OF THE FAR NORTHERN COUNTIES
WHERE SUNSHINE WILL CONTINUE FOR THE NEXT FEW HOURS AND MAY ENABLE
LOCATIONS LIKE KOKOMO AND MUNCIE TO MAKE A RUN AT 70 LATER TODAY.
ZONE AND GRID UPDATES OUT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 326 AM EDT SAT APR 27 2013
FOCUS CONTINUES TO BE ON CHANCES FOR RAIN THROUGH THE PERIOD. MODELS
ARE CLOSE ENOUGH THAT A BLEND CAN BE USED FOR MOST ITEMS.
Q-VECTOR FORECAST PLOTS SHOW THE FORCING MOVING INTO THE AREA
TONIGHT ASSOCIATED WITH AN UPPER LOW MOVING INTO THE AREA...SO
GRADUALLY INCREASED POPS ACROSS THE FORECAST AREA TONIGHT. WENT
CLOSE TO MOS POPS WITH LIKELY NORTH AND CATEGORICAL SOUTH.
ON SUNDAY THE SURFACE AND UPPER LOWS WILL MOVE THROUGH THE AREA. MOS
POPS ARE HIGH...BUT MODELS ARE ONLY SHOWING RELATIVELY WEAK FORCING.
FORECAST REFLECTIVITY ALSO SHOWS MORE OF A SCATTERED COVERAGE THAN
WIDESPREAD AT ANY ONE TIME. HOWEVER WITH THE LOWS MOVING THROUGH
CANNOT REALLY ARGUE AGAINST THE HIGH POPS SINCE MOST AREAS COULD SEE
A HUNDREDTH OF AN INCH IN A PASSING SHOWER. WITH THE HIGH POPS WILL
USE OCCASIONAL WORDING TO HIGHLIGHT DRY PERIODS DURING THE
DAY.
SOME INSTABILITY MOVES IN WITH THE SURFACE LOW SO MENTIONED ISOLATED
THUNDERSTORMS SUNDAY.
WENT LOW POPS SUNDAY EVENING AS MODELS CONTINUE TO HINT AT LINGERING
PRECIPITATION. FOR OVERNIGHT SUNDAY NIGHT INTO MONDAY WENT SLIGHT
CHANCE POPS ACROSS THE EAST FOR THE SAME REASON.
FOR TEMPERATURES THROUGH THE FIRST HALF OF THE PERIOD...GENERALLY
WENT WITH THE COOLER OF THE MOS DURING THE DAY AND THE WARMER OF THE
MOS DURING THE NIGHT DUE TO CLOUDS AND RAINFALL. GENERALLY STUCK
WITH A BLEND FOR THE SECOND HALF.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 300 AM EDT SAT APR 27 2013
MODEL TIMING DIFFERENCES REGARDING AN UPPER LOW AND UPSTREAM FRONTAL
SYSTEM WILL CONTINUE TO BE THE MAIN ISSUE IN THE EXTENDED ESPECIALLY
LATE WEEK.
THE 00Z GFS AND GEFS CONTINUE TO BE MUCH FASTER AND WEAKER WITH THE
AFOREMENTIONED UPPER SYSTEM. BY 00Z FRIDAY...THE 12Z ECMWF HAS A
DEEP UPPER LOW ACROSS NORTHEASTERN NEBRASKA...WHILE THE 00Z GFS AND
GEFS HAVE A WEAKER OPEN TROUGH ACROSS EASTERN MISSOURI AND FINALLY
THE 00Z GEM HAS AN UPPER LOW FORMING WITHIN THE TROUGH ACROSS
NORTHERN TEXAS. MEANWHILE...THE GFS AND GEFS WERE MUCH FASTER WITH
THE LEAD FRONT WITH THE ECMWF AND TO A LESSER EXTENT EURO LAGGING
WELL TO THE WEST. THE GEFS AND GFS HAVE THE FRONT ACROSS OHIO...THE
GEM ACROSS EASTERN INDIANA AND EURO ACROSS WESTERN INDIANA AT THAT
TIME. THIS RESULTS IN QUICKER MOISTURE RETURN AND QPF FROM THE GFS
AND GEFS. THE GFS AND GEFS HAS DECENT QPF BY WEDNESDAY NIGHT...WHILE
THE OTHER LONG RANGE MODELS HOLD OFF TIL WEDNESDAY.
WITH A STRONG RIDGING ACROSS THE EASTERN SEABOARD AS WELL AS THE
WEST...PREFER THE SLOWER ECMWF BUT WILL ALLOW FOR SMALL POPS OF THE
REGIONAL INITIALIZATION ON WEDNESDAY IN THE SMALL CHANCE THE GFS
VERIFIES OR THE EURO AND GEM SPEED UP A LITTLE BIT IN LATER RUNS.
ALL MODELS HAVE DECENT QPF ON THURSDAY AND HOLD ON TO IT ALSO FRIDAY
WHICH IS REFLECTED IN CONTINUED REGIONAL INITIALIZATION POPS.
AGAIN WITH LOW CONFIDENCE FROM MODEL DIFFERENCES...WILL ACCEPT THE
REGIONAL TEMPERATURES WHICH HAVE HIGHS IN THE 70S THROUGH WEDNESDAY
AND THEN PROGRESSIVELY COOLER NUMBERS IN THE 60S ON THURSDAY AND 50S
BY FRIDAY AS COLD FRONT SLIDES TO THE EAST.
&&
.AVIATION /DISCUSSION FOR 271500Z TAF UPDATE/...
ISSUED AT 1015 AM EDT FRI APR 27 2013
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
LIGHT RAIN WILL GRADUALLY SPREAD NORTHEAST ACROSS THE TAF SITES
REACHING LAF AND BMG FROM 16Z-18Z...IND FROM 18Z-20Z AND LAF FROM
20-22Z. AS THE RAIN FALLS...VFR CONDITIONS WILL BECOME MVFR AND THEN
IFR SHORTLY THEREAFTER AND REMAIN THAT WAY THROUGH THE NIGHT.
WINDS WILL BE LESS THAN 10 KNOTS FROM THE SOUTHEAST TODAY AND BECOME
LIGHT AND VARIABLE AFTER 00Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....MK
AVIATION...MK/TDUD
AREA FORECAST DISCUSSION
NWS WICHITA KS
1222 PM CDT SAT APR 27 2013
.SYNOPSIS...
ISSUED AT 337 AM CDT SAT APR 27 2013
SCATTERED SHOWERS AND DRIZZLE ARE SLOWLY MAKING THEIR WAY EASTWARD
AS THE UPPER LEVEL SYSTEM MOVES ACROSS THE PLAINS. WHERE CLOUDS
HAVE THINNED OR CLEARED OUT...DENSE FOG HAS DEVELOPED ACROSS
WESTERN AND NORTHERN KANSAS. WINDS HAVE BECOME NORTH TO
NORTHEASTERLY AND ARE LIGHT.
BILLINGS
&&
.UPDATE...
ISSUED AT 1220 PM CDT SAT APR 27 2013
THE CLOUDS HAVE FINALLY STARTED TO ABATE OVER THE WESTERN PART OF
THE FORECAST AREA. CENTRAL KANSAS OVER THE LAST COUPLE OF HOURS
HAS SEEN A SIGNIFICANT REDUCTION OF CLOUDS. MOREOVER...THE
PRECIPITATION OVER EASTERN KANSAS HAS BEEN RELEGATED TO A FEW
SPRINKLES.
THE LAST FEW RUNS OF THE HRRR AND RUC ARE ON TRACK WITH THESE
TRENDS. HAVE ADJUSTED TEMPERATURES TO INDICATED A QUICK WARM UP
THIS AFTERNOON ONCE THE CLOUDS CLEAR. THE MAIN PROBLEM IS
REALLY OVER SOUTHEAST KANSAS AND HOW LONG THE CLOUDS WILL BE
THERE...WHICH WILL AFFECT HIGHS. WILL KEEP HIGHS NEAR 60 THERE FOR
NOW.
FINALLY...THE HRRR HAS CONSISTENTLY INDICATED WEAK CONVECTIVE
DEVELOPMENT FROM THE UPPER LEVEL COLD POOL. THAT COULD BE ENTIRELY
POSSIBLE...BUT AT THIS TIME HAVE REDUCED PRECIPITATION CHANCES AND
JUST STUCK WITH SOME SPRINKLES...WHICH I THINK BETTER INDICATES
WHAT IS EXPECTED.
COOK
UPDATE ISSUED AT 616 AM CDT SAT APR 27 2013
UPDATED THE AVIATION SECTION BELOW FOR THE 12Z TAFS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 337 AM CDT SAT APR 27 2013
THE UPPER LEVEL SYSTEM WILL SLOWLY CONTINUE TO MOVE OUT OF THE
AREA TODAY. EXPECTING SHOWERS AND DRIZZLE TO LINGER ACROSS
SOUTHEASTERN KANSAS THROUGH PART OF THE MORNING. SKIES WILL CLEAR
OUT FROM WEST TO EAST...AND TEMPERATURES WILL RETURN TO NEAR NORMAL.
HOWEVER...TEMPS WILL BE SLIGHTLY COOLER WHERE CLOUDS LINGER
THROUGH PART OF THE DAY. ANOTHER BRIEF WAVE WILL QUICKLY MOVE
ACROSS THE CENTRAL PLAINS...BUT DO LITTLE TO THE SURFACE PATTERN
OVER THE AREA. TEMPERATURES ON SUNDAY AND MONDAY WILL BE IN THE
LOW 80S WITH SOUTHERLY WINDS.
BILLINGS
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 337 AM CDT SAT APR 27 2013
THIS PERIOD IS THE ONE TO WATCH. THE GUIDANCE HAS CONTINUED TO
SHOW AN UPPER WAVE BEING CUT OFF FROM THE MAIN FLOW AND ROTATING
AROUND THE MIDDLE OF THE COUNTRY FOR THURSDAY AND FRIDAY. WHILE THE
GUIDANCE HAS BEEN CONSISTENT IN SHOWING THIS SOLUTION...THEY DO
DIFFER ON TIMING AND PLACEMENT OF THE WAVE/CUT-OFF LOW. THE GFS
AND ECMWF ARE FAIRLY CONSISTENT WITH THE STRONG COLD FRONT MOVING
THROUGH THE REGION ON WEDNESDAY NIGHT/THURSDAY MORNING...BUT THE
GFS BECOMES MORE PROGRESSIVE WITH THE WAVE AS IT PUSHES THE FRONT
THROUGH TO THE OHIO VALLEY...WHILE THE ECMWF KEEPS THE CUT-OFF
LOW OVER THE CENTRAL/SOUTHERN PLAINS.
THESE DISCREPANCIES DO HAVE LARGE IMPACT ON THE FORECAST...WITH
THE GFS KEEPING MOST OF THE PRECIPITATION OVER THE OHIO VALLEY
WHILE THE ECMWF KEEPS THE COOL AIR AND PRECIPITATION OVER KANSAS.
MUCH LIKE THE PREVIOUS FORECAST...THE CONSENSUS WEIGHS MORE
HEAVILY ON THE GFS SOLUTION THAN THE ECMWF...SO IT HAS
PRECIPITATION EXITING THE AREA ON THURSDAY...HOWEVER...IF THE
ECMWF REMAINS CONSISTENT OVER THE NEXT FEW DAYS THE END OF THE
WEEK AND INTO THE WEEKEND NEXT WEEK (BEYOND THE PERIOD) WILL BE
COOL AND RAINY.
BILLINGS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1220 PM CDT SAT APR 27 2013
THE FOG IS MORE OR LESS GONE ACROSS THE AREA...WITH VERY LITTLE
PRECIPITATION. BKN010 CLOUDS MAINLY ALONG AND EAST OF THE KANSAS
TURNPIKE WILL GRADUALLY MOVE EAST. IT SHOULD BE OUT OF
KICT/KHUT/KSLN BY 27.19Z AND OUT OF KCNU BEFORE 28.00Z.
FOG IS EXPECTED TO REDEVELOP AROUND 28.08Z AND LAST THROUGH 28.13Z
AT ALL STATIONS WITH THE EXCEPTION OF KRSL...WHERE THE RIDGE OF
HIGH PRESSURE MOVING IN MAY LIMIT THE FOG DEVELOPMENT.
COOK
&&
.FIRE WEATHER...
ISSUED AT 337 AM CDT SAT APR 27 2013
DESPITE THE WARM TEMPERATURES...THE LIGHT WINDS EXPECTED OVER THE
NEXT COUPLE OF DAYS WILL KEEP GRASSLAND FIRE DANGER LOW.
HOWEVER...VERY HIGH FIRE DANGER IS POSSIBLE TUESDAY WITH GUSTY
SOUTHWEST WINDS AND WARM TEMPERATURES AHEAD OF THE COLD FRONT.
AFTER THE FRONT PASSES...TEMPERATURES WILL COOL AND PRECIPITATION
WILL KEEP FIRE WEATHER CONCERNS AT BAY.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 67 49 81 55 / 20 10 0 0
HUTCHINSON 68 47 82 55 / 10 10 0 0
NEWTON 67 49 80 56 / 30 10 0 0
ELDORADO 66 47 79 55 / 50 10 0 0
WINFIELD-KWLD 68 48 80 56 / 30 10 0 0
RUSSELL 71 47 83 53 / 10 0 0 0
GREAT BEND 72 47 84 54 / 10 0 0 0
SALINA 67 47 82 55 / 10 10 0 0
MCPHERSON 67 47 82 55 / 10 10 0 0
COFFEYVILLE 60 46 77 55 / 60 10 0 0
CHANUTE 60 45 76 54 / 60 10 0 0
IOLA 60 45 76 54 / 60 10 0 0
PARSONS-KPPF 60 46 77 55 / 60 10 0 0
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
402 AM CDT SAT APR 27 2013
.SYNOPSIS...
ISSUED AT 400 AM CDT SAT APR 27 2013
THE 00 UTC OBJECTIVE ANALYSIS INDICATED THE 700 MB LOW WAS
POSITIONED ACROSS SOUTH CENTRAL KANSAS AND SLOWLY TRANSLATING
EASTWARD WITH TIME. THE UPPER FLOW WAS SPLIT WITH THE MAIN UPPER JET
ENERGY FOCUSED ACROSS CANADA AND THE SOUTHERN PLAINS. THIS SLOWLY
MOVING SYSTEM WAS RESPONSIBLE FOR A DECAYING MCS ACROSS CENTRAL
OKLAHOMA OVERNIGHT AND WIDESPREAD STRATUS AND DEVELOPING FOG ACROSS
CENTRAL AND WESTERN KANSAS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 400 AM CDT SAT APR 27 2013
THE CONCERNS IN THE SHORT TERM WILL REVOLVE AROUND FOG THIS MORNING,
FOLLOWED BY TEMPERATURES AND CLEARING THIS AFTERNOON. THE
AFOREMENTIONED 700-500 MB LOW CENTER IS FORECAST TO BE POSITIONED
ACROSS SOUTHEAST KANSAS BY AROUND 12 UTC AND OVER MISSOURI BY THIS
EVENING. WESTERN KANSAS WILL SLOWLY COME UNDER THE INFLUENCE OF
NORTHWEST FLOW ALOFT AND INCREASED SUBSIDENCE ALOFT. WINDS SHOULD
REMAIN LIGHT AND VARIABLE GIVEN THE PRESENCE OF A SURFACE RIDGE
EXTENDING FROM THE UPPER MISSISSIPPI VALLEY INTO CENTRAL KANSAS.
JUST HOW LONG FOG PERSISTS THIS MORNING WILL FIRST DEPEND ON HOW
EXTENSIVE THE FOG DEVELOPS BETWEEN 10 AND 13Z UNDER THE CLEARING MID
LEVEL CLOUDS. LIGHT WESTERLY WINDS MIGHT ALLOW IMPROVEMENT IN THE
SCOTT CITY TO GARDEN CITY AND EVEN DODGE CITY AREAS THIS MORNING,
BUT LIGHT AND VARIABLE WINDS ARE MORE CONCERNING FOR DENSE FOG
ESPECIALLY AROUND HAYS AND SOUTHWARD.
THE BOUNDARY LAYER WILL BE MUCH DRIER ACROSS THE FAR WESTERN KANSAS
COUNTIES THIS AFTERNOON WHICH SHOULD ALLOW TEMPERATURES TO RAPIDLY
WARM INTO THE MID 70`S F BY AROUND NOON. AT THE SAME TIME,
TEMPERATURES ACROSS SOUTH CENTRAL KANSAS, HINDERED BY NORTHEASTERLY
WINDS WILL LIKELY WARM SLOWER, STRUGGLING THROUGH THE 60S FOR MUCH
OF THE DAY. HIGHS NEAR 70 DEGREES SHOULD BE ACHIEVABLE BY MID TO
LATE AFTERNOON. BY SATURDAY NIGHT INTO EARLY SUNDAY MORNING LIGHT
SOUTHWEST WINDS WILL BECOME ESTABLISHED ACROSS THE REGION. WITH NO
SIGNIFICANT CHANGE IN BOUNDARY AIRMASS AND DEW POINTS REMAINING IN
THE MID 40`S, A GENERALLY MILD OVERNIGHT IS EXPECTED. WITH SOUTHWEST
FLOW, FOG DEVELOPMENT IS NOT ANTICIPATED.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 400 AM CDT SAT APR 27 2013
SUNDAY THROUGH TUESDAY:
VERY WARM WEATHER WILL BE THE STORY DURING THIS TIME FRAME...WITH
80S EXPECTED EACH DAY. TUESDAY WILL LIKELY BE THE WARMEST DAY OF THE
THREE AS THE 850-700MB THERMODYNAMIC PROFILE WILL BE VERY WARM IN
THE INCREASING MIDDLE TROPOSPHERIC DOWNSLOPE MOMENTUM. THERE WILL
LIKELY BE A DRYLINE SOMEWHERE ACROSS SOUTHWEST KANSAS INTO THE TEXAS
PANHANDLE...WITH 25 TO 35F DEWPOINTS WEST OF THE DRYLINE AND 50S TO
NEAR 60F DEWPOINTS EAST OF THE DRYLINE. THE SIGNIFICANT AMOUNT OF
WARMTH AT 700MB WILL LIKELY PUT A LID ON ANY THUNDERSTORM FORMATION
ON THE DRYLINE...SO WILL KEEP THE FORECAST TUESDAY DRY.
TUESDAY NIGHT THROUGH THURSDAY:
TO SAY THAT THE FORECAST IN THIS TIME FRAME IS CHALLENGING IS A
MAJOR UNDERSTATEMENT. EVERY SINGLE GLOBAL MODEL IS SHOWING A
PRONOUNCED UPPER LOW DEVELOPMENT ACROSS THE GREAT PLAINS OR MIDWEST
REGION FOLLOWING A POLAR JET AMPLIFICATION EVENT. AS THE TROUGH
UNDERGOES AMPLIFICATION...A VERY INTENSE COLD FRONT WILL PUSH SOUTH
QUICKLY LATE TUESDAY INTO EARLY WEDNESDAY. THE LATEST ECMWF MODEL
SHOWS A SIGNIFICANT AMOUNT OF COLD AIR BEHIND THIS FRONT...WHICH IS
SOMETHING TO TAKE SERIOUSLY BECAUSE THE ECMWF WAS THE FIRST MODEL TO
CATCH ON TO ANOMALOUS COLD EVENTS IN APRIL. YET ANOTHER ANAFRONTAL
PRECIPITATION EVENT MAY UNFOLD IN THE COLD AIR ACROSS THE CENTRAL
PLAINS AS IS SUGGESTED BY THE ECMWF...WHICH COULD INCLUDE FROZEN
PRECIPITATION AS THE 850-700MB COLUMN COOLS DOWN TO AND BELOW ZERO
CELSIUS SOMETIMES LATE WEDNESDAY OR WEDNESDAY NIGHT. AT THIS
TIME...THE OFFICIAL FORECAST WILL REMAIN ON THE CONSERVATIVE SIDE
WITH PRECIPITATION IN THE FORM OF SHOWERS AND ISOLATED
THUNDERSTORMS. IF THE ATMOSPHERE GOES IN THE DIRECTION OF THE
ECMWF...THEN WE WILL HAVE TO THINK ABOUT SOME SLEET OR WET SNOW
AGAIN! EITHER WAY...THE PERIOD WEDNESDAY THROUGH THE END OF THE
UPCOMING WEEK LOOKS WET AND COOL (IF NOT COLD).
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1242 AM CDT SAT APR 27 2013
DENSE FOG IS BECOMING MORE WIDESPREAD ACROSS SOUTHWEST KANSAS EARLY
THIS MORNING. BASED ON THE CURRENT TRENDS AND THE LAST HRRR MODEL AS
WELL AS TRENDS FROM THE LOCAL GFS MOS GUIDANCE, SEVERAL HOURS OF
LIFR/VLIFR VISIBILITIES IN DENSE FOG IS EXPECTED THROUGH SATURDAY
MORNING AT EACH OF THE AREA TERMINALS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 46 84 50 / 0 0 0 10
GCK 77 41 84 48 / 0 0 0 10
EHA 77 45 84 48 / 0 10 0 10
LBL 77 44 85 50 / 0 10 0 10
HYS 73 45 84 50 / 0 0 0 10
P28 72 48 83 55 / 0 0 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ030-031-
043>046-063>065-077>079-087-088.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...UMSCHEID
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1217 AM MDT SAT APR 27 2013
.UPDATE...
ISSUED AT 1212 AM MDT SAT APR 27 2013
FOG STARTING TO DEVELOP ACROSS THE AREA NOW...WITH DENSE FOG
ALREADY REPORTED AT OAKLEY AND VISIBILITIES FALLING TO THE NORTH
AND EAST. THINK THIS AIRMASS WILL SHIFT EAST THROUGH THE
NIGHT...BUT HAVE ISSUED ADVISORY AS FAR WEST AS COLBY AND LEOTI
AREAS AND PLAN ON CLEARING AS FOG THREAT WANES.
UPDATE ISSUED AT 827 PM MDT FRI APR 26 2013
JUST COMPLETED AN UPDATE. MAIN CHANGE WAS TO INTRODUCE FOG FOR
TONIGHT INTO MID MORNING ON SATURDAY. DDC SOUNDING AND SURFACE
OBSERVATIONS WOULD INDICATE A RATHER MOIST TO OUR SOUTH. DEWPOINTS
HAVE BEEN INCREASING AND PUSHING FARTHER WEST THAN ANYTHING
INDICATES. THIS IS A RESULT OF MODELS HANDLING THE WIND/PRESSURE
FIELD POORLY AS WELL. RUC AND HRRR APPEAR TO BE CATCHING ALL THIS
FAIRLY WELL AND USED AS THE BASIS FOR THE UPDATE. ALSO ADJUSTED
SKY COVER UP A LITTLE AND RAISED THE MINS AS WELL.
UPDATE ISSUED AT 624 PM MDT FRI APR 26 2013
LET THE RED FLAG WARNING EXPIRE. PER LATEST OBSERVATIONS INCREASED
CLOUD COVER AND ADJUSTED DEWPOINTS DOWN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 139 PM MDT FRI APR 26 2013
H5 TROUGH AXIS CURRENTLY EXTENDS ACROSS WESTERN KS...WITH H7
CLOSED CENTER OVER SW KS NEAR 0K PANHANDLE. FRONTOGENETICAL FORCING
ALONG NW EXTENT OF H7 LOW HAS COMBINED WITH ELEVATED INSTABILITY
TO PRODUCE SHOWERS AND THUNDERSTORMS OVER PARTS OF SW KS...WITH
THE EDGE OF THIS ACTIVITY JUST SOUTHEAST OF OUR CWA BORDER. SHORT
RANGE GUIDANCE KEEPS THIS ACTIVITY SOUTH AND EAST OF OUR CWA AS
THE H5/H7 TROUGH SHIFTS EAST THIS AFTERNOON AND EVENING. THERE
HAVE BEEN LIGHT RADAR RETURNS OVER OUR SOUTHEASTERN CWA...HOWEVER
WITH MUCH DRIER AIR UNDERCUTTING THE NORTHERN EDGE OF THIS ACIDITY
AND SUBSIDENCE MOVING IN FROM THE NORTHWEST I AM SKEPTICAL THAT WE
WILL SEE MUCH MORE THAN ISOLATED SHOWERS THIS AFTERNOON.
A SURFACE TROUGH AXIS IS CURRENTLY CENTERED ALONG A LINE FROM JUST
EAST OF MCCOOK TO THE SOUTHWEST KS/CO BORDER. WEST OF THIS...VERY
GOOD MIXING ASSOCIATED WITH A DEEP DRY ADIABATIC LAYER (TO ABOUT
700MB) HAS LED TO VERY WARM/DRY CONDITIONS AND GUSTY WINDS MIXING
TO THE SURFACE. RED FLAG WARNING WAS ISSUED IN RESPONSE TO RH
VALUES FALLING TO 10-20% WITH GUSTS TO 30 MPH. AS THIS SURFACE
TROUGH SHIFTS EAST THIS AFTERNOON AND HIGH PRESSURE BUILDS INTO
NORTHEAST COLORADO THE GRADIENT WILL BEGIN TO WEAKEN...AND WINDS
SHOULD DECREASE SOME. I COULD SEE ENDING THE RFW EARLY FOR WESTERN
LOCATIONS...BUT WE SHOULD STILL SEE ABOUT 3HR OF RFW CONDITIONS
BEFORE ALL IS SAID AND DONE.
ANOTHER VERY WARM DAY IS EXPECTED SATURDAY...AND IF HIGH
TEMPERATURES TODAY ARE ANY INDICATION WE SHOULD SEE WIDESPREAD
HIGHS IN THE UPPER 70S/LOW 80S...POSSIBLY WARMER. WE SHOULD ALSO
SEE RH VALUES DROP TO WITHIN RFW CRITERIA...HOWEVER WINDS ALOFT
ARE MUCH LIGHTER...SO I AM NOT EXPECTING A REPEAT OF THIS
AFTERNOON REGARDING FIRE WEATHER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 210 PM MDT FRI APR 26 2013
SATURDAY NIGHT-MONDAY...DRY. GENERALLY CLEAR THROUGH SUNDAY WITH AN
INCREASE IN MID AND HIGH LEVEL CLOUDS SUNDAY NIGHT AS A WEAK WEATHER
SYSTEM MOVES THROUGH UPPER W/NW FLOW ALOFT. BIGGER STORY WILL BE THE
VERY WARM TEMPERATURES.
HIGH TEMPERATURES SUNDAY 75 TO 80 IN FAR EASTERN COLORADO...LOW TO
MID 80S ELSEWHERE. FOR MONDAY 850 TEMPERATURES FROM GFS/NAM/ECMWF
AVERAGE A FEW DEGREES WARMER. DISCREPANCIES SHOW UP WITH REGARD TO
850 THERMAL AXIS. GFS/ECMWF INDICATING LESS AGGRESSIVE WARMING ACROSS
THE EASTERN 1/3 OF THE AREA WHILE NAM/SREF ARE SEVERAL DEGREES
WARMER. THIS DISCREPANCY RESULTS IN A SIGNIFICANT DIFFERENCE IN
TEMPERATURE AS THE COOLER SOLUTION WOULD SUGGEST HIGHS GENERALLY IN
THE MID TO UPPER 80S (WEST TO EAST) WHILE THE WARMER SOLUTIONS WOULD
SUGGEST MID 80S TO MID 90S (WEST TO EAST). IF THE WARMER SOLUTION
VERIFIES RECORD HIGH TEMPERATURES WOULD BE REACHED OR TIED JUST
ABOUT EVERYWHERE. WITH A SOUTHEAST TO SOUTH COMPONENT TO THE SFC
WIND EXPECTED DURING THE DAY WILL TREND TOWARD THE COOLER SOLUTION
WHICH STILL PRODUCES HIGHS IN THE 80S...MUCH ABOVE NORMAL FOR MANY.
TUESDAY...COLD FRONT MOVES THROUGH DURING THE DAY LOWERING AFTERNOON
TEMPERATURES INTO THE LOW TO MID 70S NORTH...LOW 80S SOUTH. HIGH
PRESSURE MOVES IN TUESDAY NIGHT WITH LOWS UPPER 30S WEST...UPPER 40S
EAST. PRECIPITATION CHANCES INCREASE TUESDAY NIGHT AS UPPER TROUGH
MOVES ACROSS THE AREA. NOT TERRIBLY EXCITED ABOUT THUNDER CHANCES
GIVEN LACK OF INSTABILITY AND WEAK MID LEVEL LAPSE RATES.
WEDNESDAY...UPPER TROUGH SLOWLY MOVES EAST ALLOWING SOME WARMER AIR
TO RETURN TO THE WESTERN 1/3 OF THE AREA. HIGH TEMPERATURES WELL
BELOW NORMAL WITH LOW TO MID 50S. LOWS WEDNESDAY NIGHT IN THE LOW TO
MID 30S. NORMALLY COLDER LOCATIONS MAY SEE TEMPERATURES AT OR
SLIGHTLY BELOW FREEZING. WILL CONTINUE WITH SMALL CHANCES FOR RAIN
SHOWERS DURING THE DAY AS UPPER WAVES AND PROXIMITY TO UPPER JET
MOVE QUICKLY THROUGH THE STEEP NORTHWEST FLOW ALOFT. DRY CONDITIONS
EXPECTED WEDNESDAY NIGHT.
THURSDAY-FRIDAY...DRY. TEMPERATURES SLOWLY WARM THROUGH THE PERIOD
WITH HIGHS THURSDAY AROUND 60...65 TO 70 FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1140 PM MDT FRI APR 26 2013
VERY DIFFERENT AIRMASS IN PLACE ACROSS THE AREA TONIGHT WITH DRY
AIR ACROSS THE NORTHWEST AND MUCH MORE HUMID AIR MOVING INTO
EASTERN HALF OF THE FORECAST AREA. OBSERVED SOUNDINGS AT 00Z
SUGGEST THAT HUMIDITY PROFILES ARE FAVORABLE FOR FOG
FORMATION...WITH MAIN CONCERN BEING WHERE DIVIDING LINE BETWEEN
THESE TWO AIR MASSES WILL BE OVERNIGHT. CONFIDENCE IN FOG MUCH
HIGHER AT MCK THAN GLD...BUT EVEN THEN MAJORITY OF GUIDANCE
SUGGEST WINDS WILL SHIFT TO THE WEST AND KEEP FOG TO THE SOUTH AND
EAST OF THE AREA. FOR THE TIME BEING...THINK KEEPING OPERATIONALLY
SIGNIFICANT VISBY RESTRICTIONS WARRANTED FOR THE TIME BEING BUT
CONFIDENCE NOT HIGH ENOUGH FOR WIDESPREAD IFR/LIFR VISBYS.
OTHERWISE....VFR CONDITIONS EXPECTED AFTER 15Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ003-004-
014>016-028-029-042.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...DR
LONG TERM...99
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1149 PM MDT FRI APR 26 2013
.UPDATE...
ISSUED AT 827 PM MDT FRI APR 26 2013
JUST COMPLETED AN UPDATE. MAIN CHANGE WAS TO INTRODUCE FOG FOR
TONIGHT INTO MID MORNING ON SATURDAY. DDC SOUNDING AND SURFACE
OBSERVATIONS WOULD INDICATE A RATHER MOIST TO OUR SOUTH. DEWPOINTS
HAVE BEEN INCREASING AND PUSHING FARTHER WEST THAN ANYTHING
INDICATES. THIS IS A RESULT OF MODELS HANDLING THE WIND/PRESSURE
FIELD POORLY AS WELL. RUC AND HRRR APPEAR TO BE CATCHING ALL THIS
FAIRLY WELL AND USED AS THE BASIS FOR THE UPDATE. ALSO ADJUSTED
SKY COVER UP A LITTLE AND RAISED THE MINS AS WELL.
UPDATE ISSUED AT 624 PM MDT FRI APR 26 2013
LET THE RED FLAG WARNING EXPIRE. PER LATEST OBSERVATIONS INCREASED
CLOUD COVER AND ADJUSTED DEWPOINTS DOWN.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 139 PM MDT FRI APR 26 2013
H5 TROUGH AXIS CURRENTLY EXTENDS ACROSS WESTERN KS...WITH H7
CLOSED CENTER OVER SW KS NEAR 0K PANHANDLE. FRONTOGENETICAL FORCING
ALONG NW EXTENT OF H7 LOW HAS COMBINED WITH ELEVATED INSTABILITY
TO PRODUCE SHOWERS AND THUNDERSTORMS OVER PARTS OF SW KS...WITH
THE EDGE OF THIS ACTIVITY JUST SOUTHEAST OF OUR CWA BORDER. SHORT
RANGE GUIDANCE KEEPS THIS ACTIVITY SOUTH AND EAST OF OUR CWA AS
THE H5/H7 TROUGH SHIFTS EAST THIS AFTERNOON AND EVENING. THERE
HAVE BEEN LIGHT RADAR RETURNS OVER OUR SOUTHEASTERN CWA...HOWEVER
WITH MUCH DRIER AIR UNDERCUTTING THE NORTHERN EDGE OF THIS ACIDITY
AND SUBSIDENCE MOVING IN FROM THE NORTHWEST I AM SKEPTICAL THAT WE
WILL SEE MUCH MORE THAN ISOLATED SHOWERS THIS AFTERNOON.
A SURFACE TROUGH AXIS IS CURRENTLY CENTERED ALONG A LINE FROM JUST
EAST OF MCCOOK TO THE SOUTHWEST KS/CO BORDER. WEST OF THIS...VERY
GOOD MIXING ASSOCIATED WITH A DEEP DRY ADIABATIC LAYER (TO ABOUT
700MB) HAS LED TO VERY WARM/DRY CONDITIONS AND GUSTY WINDS MIXING
TO THE SURFACE. RED FLAG WARNING WAS ISSUED IN RESPONSE TO RH
VALUES FALLING TO 10-20% WITH GUSTS TO 30 MPH. AS THIS SURFACE
TROUGH SHIFTS EAST THIS AFTERNOON AND HIGH PRESSURE BUILDS INTO
NORTHEAST COLORADO THE GRADIENT WILL BEGIN TO WEAKEN...AND WINDS
SHOULD DECREASE SOME. I COULD SEE ENDING THE RFW EARLY FOR WESTERN
LOCATIONS...BUT WE SHOULD STILL SEE ABOUT 3HR OF RFW CONDITIONS
BEFORE ALL IS SAID AND DONE.
ANOTHER VERY WARM DAY IS EXPECTED SATURDAY...AND IF HIGH
TEMPERATURES TODAY ARE ANY INDICATION WE SHOULD SEE WIDESPREAD
HIGHS IN THE UPPER 70S/LOW 80S...POSSIBLY WARMER. WE SHOULD ALSO
SEE RH VALUES DROP TO WITHIN RFW CRITERIA...HOWEVER WINDS ALOFT
ARE MUCH LIGHTER...SO I AM NOT EXPECTING A REPEAT OF THIS
AFTERNOON REGARDING FIRE WEATHER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 210 PM MDT FRI APR 26 2013
SATURDAY NIGHT-MONDAY...DRY. GENERALLY CLEAR THROUGH SUNDAY WITH AN
INCREASE IN MID AND HIGH LEVEL CLOUDS SUNDAY NIGHT AS A WEAK WEATHER
SYSTEM MOVES THROUGH UPPER W/NW FLOW ALOFT. BIGGER STORY WILL BE THE
VERY WARM TEMPERATURES.
HIGH TEMPERATURES SUNDAY 75 TO 80 IN FAR EASTERN COLORADO...LOW TO
MID 80S ELSEWHERE. FOR MONDAY 850 TEMPERATURES FROM GFS/NAM/ECMWF
AVERAGE A FEW DEGREES WARMER. DISCREPANCIES SHOW UP WITH REGARD TO
850 THERMAL AXIS. GFS/ECMWF INDICATING LESS AGGRESSIVE WARMING ACROSS
THE EASTERN 1/3 OF THE AREA WHILE NAM/SREF ARE SEVERAL DEGREES
WARMER. THIS DISCREPANCY RESULTS IN A SIGNIFICANT DIFFERENCE IN
TEMPERATURE AS THE COOLER SOLUTION WOULD SUGGEST HIGHS GENERALLY IN
THE MID TO UPPER 80S (WEST TO EAST) WHILE THE WARMER SOLUTIONS WOULD
SUGGEST MID 80S TO MID 90S (WEST TO EAST). IF THE WARMER SOLUTION
VERIFIES RECORD HIGH TEMPERATURES WOULD BE REACHED OR TIED JUST
ABOUT EVERYWHERE. WITH A SOUTHEAST TO SOUTH COMPONENT TO THE SFC
WIND EXPECTED DURING THE DAY WILL TREND TOWARD THE COOLER SOLUTION
WHICH STILL PRODUCES HIGHS IN THE 80S...MUCH ABOVE NORMAL FOR MANY.
TUESDAY...COLD FRONT MOVES THROUGH DURING THE DAY LOWERING AFTERNOON
TEMPERATURES INTO THE LOW TO MID 70S NORTH...LOW 80S SOUTH. HIGH
PRESSURE MOVES IN TUESDAY NIGHT WITH LOWS UPPER 30S WEST...UPPER 40S
EAST. PRECIPITATION CHANCES INCREASE TUESDAY NIGHT AS UPPER TROUGH
MOVES ACROSS THE AREA. NOT TERRIBLY EXCITED ABOUT THUNDER CHANCES
GIVEN LACK OF INSTABILITY AND WEAK MID LEVEL LAPSE RATES.
WEDNESDAY...UPPER TROUGH SLOWLY MOVES EAST ALLOWING SOME WARMER AIR
TO RETURN TO THE WESTERN 1/3 OF THE AREA. HIGH TEMPERATURES WELL
BELOW NORMAL WITH LOW TO MID 50S. LOWS WEDNESDAY NIGHT IN THE LOW TO
MID 30S. NORMALLY COLDER LOCATIONS MAY SEE TEMPERATURES AT OR
SLIGHTLY BELOW FREEZING. WILL CONTINUE WITH SMALL CHANCES FOR RAIN
SHOWERS DURING THE DAY AS UPPER WAVES AND PROXIMITY TO UPPER JET
MOVE QUICKLY THROUGH THE STEEP NORTHWEST FLOW ALOFT. DRY CONDITIONS
EXPECTED WEDNESDAY NIGHT.
THURSDAY-FRIDAY...DRY. TEMPERATURES SLOWLY WARM THROUGH THE PERIOD
WITH HIGHS THURSDAY AROUND 60...65 TO 70 FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1140 PM MDT FRI APR 26 2013
VERY DIFFERENT AIRMASS IN PLACE ACROSS THE AREA TONIGHT WITH DRY
AIR ACROSS THE NORTHWEST AND MUCH MORE HUMID AIR MOVING INTO
EASTERN HALF OF THE FORECAST AREA. OBSERVED SOUNDINGS AT 00Z
SUGGEST THAT HUMIDITY PROFILES ARE FAVORABLE FOR FOG
FORMATION...WITH MAIN CONCERN BEING WHERE DIVIDING LINE BETWEEN
THESE TWO AIR MASSES WILL BE OVERNIGHT. CONFIDENCE IN FOG MUCH
HIGHER AT MCK THAN GLD...BUT EVEN THEN MAJORITY OF GUIDANCE
SUGGEST WINDS WILL SHIFT TO THE WEST AND KEEP FOG TO THE SOUTH AND
EAST OF THE AREA. FOR THE TIME BEING...THINK KEEPING OPERATIONALLY
SIGNIFICANT VISBY RESTRICTIONS WARRANTED FOR THE TIME BEING BUT
CONFIDENCE NOT HIGH ENOUGH FOR WIDESPREAD IFR/LIFR VISBYS.
OTHERWISE....VFR CONDITIONS EXPECTED AFTER 15Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...99
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1245 AM CDT SAT APR 27 2013
...UPDATED FOR AVIATION...
.UPDATE...
ISSUED AT 1212 AM CDT SAT APR 27 2013
A DENSE FOG ADVISORY HAS BEEN POSTED FOR MOST OF THE REGION BETWEEN
HIGHWAYS 83 AND 183. WIDESPREAD 1 TO 3 DEGREE DEW POINT DEPRESSIONS
CHARACTERIZE THE BOUNDARY LAYER IN THIS REGION, WHILE THE FAR WEST
PERIPHERY FROM GARDEN CITY TO SCOTT CITY HAS ALREADY SEEN
VISIBILITIES DOWN TO 1/4 MILE OR LESS OVER THE LAST COUPLE OF HOURS.
WHILE THE WRF/NAM SOLUTIONS SHOW QUITE DIFFERENT SOLUTIONS, THE
HOURLY RAPID REFRESH MODEL EXPANDS DENSE FOG EASTWARD TO NEAR A HAYS
TO MINNEOLA LINE BY 12Z. GIVEN THE CURRENT TRENDS, THIS SEEM LIKE
THE MOST PROBABLE CASE.
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 210 PM CDT FRI APR 26 2013
SHOWERS AND A FEW ISOLATED THUNDERSTORMS WILL LINGER ACROSS CENTRAL
KANSAS THIS EVENING AS AN UPPER LEVEL SHORTWAVE TRANSITIONS EAST
ACROSS THE CENTRAL PLAINS THROUGH SATURDAY MORNING. PRECIP IS
EXPECTED TO DISSIPATE WEST TO EAST THROUGH LATE THIS EVENING.
WIDESPREAD SEVERE WEATHER IS NOT EXPECTED WITH LIMITED INSTABILITY
PRESENT ACROSS THE AREA. OTHERWISE, DRY AND TRANQUIL CONDITIONS
ARE EXPECTED LATE TONIGHT THROUGH SATURDAY AS THE UPPER LEVEL
FEATURE KICKS FURTHER OFF TO THE EAST WHILE DRIER AIR NEAR THE
SURFACE FILTERS SOUTH INTO WESTERN KANSAS. TEMPERATURES WILL BE
SLIGHTLY COOLER TONIGHT AS A LOW LEVEL NORTHERLY FLOW SETS UP
ACROSS WESTERN KANSAS BEHIND A SURFACE LOW DROPPING SOUTHEAST INTO
NORTH TEXAS. WITH SURFACE DEWPOINTS DROPPING INTO THE 30S(F)
ACROSS WEST CENTRAL KANSAS TO THE 40S(F) ELSEWHERE, LOOK FOR LOWS
MAINLY DOWN INTO THE 40S(F) ACROSS CENTRAL AND SOUTHWEST KANSAS
WITH THE UPPER 30S(F) POSSIBLE IN WEST CENTRAL KANSAS. FOR
SATURDAY, THE SURFACE LOW IS PROJECTED TO PUSH EAST FROM NORTH
TEXAS INTO THE ARK-LA-TEX REGION HELPING TO TURN THE NORTHERLY LOW
LEVEL FLOW MORE NORTHEASTERLY BY SATURDAY AFTERNOON. THE SAME
GENERAL AIR MASS IS EXPECTED TO REMAIN IN PLACE WITH H85
TEMPERATURES RANGING FROM AROUND 10C IN CENTRAL KANSAS TO NEAR 18C
IN FAR SOUTHWEST KANSAS. HOWEVER, WITH DECREASING CLOUDS LOOK FOR
WIDESPREAD 70S(F) FOR HIGHS ACROSS CENTRAL AND SOUTHWEST KANSAS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 333 PM CDT FRI APR 26 2013
THE ECMWF, GFS AND GEM MODELS HAVE ALL CHANGED A LITTLE SINCE
YESTERDAY. THEY ALL KEEP VERY WARM AIR ADVECTING STRONGLY NORTHWARD
SUNDAY, MONDAY AND EVEN MORE SO ON TUESDAY, BEFORE A STRONG COLD
FRONT WILL PLOW SOUTHEASTWARD THROUGH WESTERN KANSAS TUESDAY NIGHT
AND WEDNESDAY. THE UPPER LEVEL WAVE ASSOCIATED WITH THIS FRONT WILL
BE SOMEWHAT DELAYED, CROSSING WESTERN KANSAS WEDNESDAY INTO
WEDNESDAY NIGHT. FOR THIS REASON, AT THIS TIME, I DO NOT EXPECT VERY
MUCH SEVERE WEATHER TO DEVELOP, AND MORE LIKE A ROUND OF ELEVATED
SHOWERS AND THUNDERSTORMS. ALSO, DUE TO THE TIMING OF THE FASTER
MOVING FRONT AND THE DELAYED UPPER LEVEL WAVE, NO PRECIPITATION
CHANCES ARE IN OUR FORECAST AREA FOR TUESDAY AFTERNOON. THE
HIGHEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON
WEDNESDAY, RANGING FROM 30 PERCENT NORTH OF I-70, TO 50 PERCENT
DOWN SOUTHEAST IN THE PRATT TO COLDWATER AREAS. THERE WILL BE 20
PERCENT POPS IN FOR WEDNESDAY NIGHT, BUT JUST IN OUR EASTERN ZONES
MAINLY EAST OF HIGHWAY 283. QPF DOES NOT LOOK TOO SIGNIFICANT
WITH THIS SYSTEM, SO THE DROUGHT WILL CONTINUE AND PERSIST. 850
TEMPS FROM BOTH THE ECMWF AND GFS MODELS SHOW +18C AIR IN OUR
EASTERN CWA AND AS MUCH AS +24C ALONG OUR WESTERN BOUNDARY WITH
COLORADO FOR SUNDAY. BY MONDAY, THE 850MB ATMOSPHERE WILL WARM TO
NEAR +20C ALONG THE PRATT AND KINGMAN LINE, AND TO THE 24C TO 25C
DEGREE RANGE IN THE WEST NEAR COLORADO. THE WARMEST DAY MAY BE
TUESDAY, ESPECIALLY IN OUR SOUTHWEST CORNER NEAR ELKHART AND
LIBERAL, WHERE TEMPERATURES MAY SOAR INTO THE MIDDLE 80S.
JUST HOW FAST THE COLD FRONT COMES DOWN TUESDAY NIGHT IS HANDLED
DIFFERENTLY BY THE LONG RANGE MODELS. THE GFS IS THE FASTEST, AND
THE ECMWF IS SLOWER. FOR NOW, THE CONSENSUS WAS TO GO WITH THE
SLOWER EC MODEL. EITHER WAY, WEDNESDAY LOOKS CONSIDERABLY COLDER
THAN TUESDAY, BY ABOUT 19F TO 25F DEGREES. FOR BOTH WEDNESDAY AND
THURSDAY, WE WILL BE IN THE GRIP OF A COLD HIGH PRESSURE SYSTEM.
HIGHS WILL ONLY BE IN THE UPPER 50S TO LOWER 60S. THE LOWER LEVEL
FLOW WILL RETURN TO THE SOUTH BY FRIDAY, AND FRIDAY SHOULD WARM TO
THE MID 60S TO LOWER 70S. MINIMUM TEMPERATURES WILL RANGE FROM 45F
TO 55F DEGREES SUNDAY AND MONDAY, FROM 50F TO 60F DEGREES TUESDAY,
AND BACK TO THE 45F TO 55F DEGREE RANGE WEDNESDAY. BOTH THURSDAY
AND FRIDAY MORNINGS LOOK COLD, WITH LOWS DIPPING DOWN INTO THE MID
30S TO NEAR 40F DEGREES.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 210 PM CDT FRI APR 26 2013
SHOWERS AND A FEW ISOLATED THUNDERSTORMS WILL LINGER ACROSS CENTRAL
KANSAS THIS EVENING AS AN UPPER LEVEL SHORTWAVE TRANSITIONS EAST
ACROSS THE CENTRAL PLAINS THROUGH SATURDAY MORNING. PRECIP IS
EXPECTED TO DISSIPATE WEST TO EAST THROUGH LATE THIS EVENING.
WIDESPREAD SEVERE WEATHER IS NOT EXPECTED WITH LIMITED INSTABILITY
PRESENT ACROSS THE AREA. OTHERWISE, DRY AND TRANQUIL CONDITIONS
ARE EXPECTED LATE TONIGHT THROUGH SATURDAY AS THE UPPER LEVEL
FEATURE KICKS FURTHER OFF TO THE EAST WHILE DRIER AIR NEAR THE
SURFACE FILTERS SOUTH INTO WESTERN KANSAS. TEMPERATURES WILL BE
SLIGHTLY COOLER TONIGHT AS A LOW LEVEL NORTHERLY FLOW SETS UP
ACROSS WESTERN KANSAS BEHIND A SURFACE LOW DROPPING SOUTHEAST INTO
NORTH TEXAS. WITH SURFACE DEWPOINTS DROPPING INTO THE 30S(F)
ACROSS WEST CENTRAL KANSAS TO THE 40S(F) ELSEWHERE, LOOK FOR LOWS
MAINLY DOWN INTO THE 40S(F) ACROSS CENTRAL AND SOUTHWEST KANSAS
WITH THE UPPER 30S(F) POSSIBLE IN WEST CENTRAL KANSAS. FOR
SATURDAY, THE SURFACE LOW IS PROJECTED TO PUSH EAST FROM NORTH
TEXAS INTO THE ARK-LA-TEX REGION HELPING TO TURN THE NORTHERLY LOW
LEVEL FLOW MORE NORTHEASTERLY BY SATURDAY AFTERNOON. THE SAME
GENERAL AIR MASS IS EXPECTED TO REMAIN IN PLACE WITH H85
TEMPERATURES RANGING FROM AROUND 10C IN CENTRAL KANSAS TO NEAR 18C
IN FAR SOUTHWEST KANSAS. HOWEVER, WITH DECREASING CLOUDS LOOK FOR
WIDESPREAD 70S(F) FOR HIGHS ACROSS CENTRAL AND SOUTHWEST KANSAS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 333 PM CDT FRI APR 26 2013
THE ECMWF, GFS AND GEM MODELS HAVE ALL CHANGED A LITTLE SINCE
YESTERDAY. THEY ALL KEEP VERY WARM AIR ADVECTING STRONGLY NORTHWARD
SUNDAY, MONDAY AND EVEN MORE SO ON TUESDAY, BEFORE A STRONG COLD
FRONT WILL PLOW SOUTHEASTWARD THROUGH WESTERN KANSAS TUESDAY NIGHT
AND WEDNESDAY. THE UPPER LEVEL WAVE ASSOCIATED WITH THIS FRONT WILL
BE SOMEWHAT DELAYED, CROSSING WESTERN KANSAS WEDNESDAY INTO
WEDNESDAY NIGHT. FOR THIS REASON, AT THIS TIME, I DO NOT EXPECT VERY
MUCH SEVERE WEATHER TO DEVELOP, AND MORE LIKE A ROUND OF ELEVATED
SHOWERS AND THUNDERSTORMS. ALSO, DUE TO THE TIMING OF THE FASTER
MOVING FRONT AND THE DELAYED UPPER LEVEL WAVE, NO PRECIPITATION
CHANCES ARE IN OUR FORECAST AREA FOR TUESDAY AFTERNOON. THE
HIGHEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE ON
WEDNESDAY, RANGING FROM 30 PERCENT NORTH OF I-70, TO 50 PERCENT
DOWN SOUTHEAST IN THE PRATT TO COLDWATER AREAS. THERE WILL BE 20
PERCENT POPS IN FOR WEDNESDAY NIGHT, BUT JUST IN OUR EASTERN ZONES
MAINLY EAST OF HIGHWAY 283. QPF DOES NOT LOOK TOO SIGNIFICANT
WITH THIS SYSTEM, SO THE DROUGHT WILL CONTINUE AND PERSIST. 850
TEMPS FROM BOTH THE ECMWF AND GFS MODELS SHOW +18C AIR IN OUR
EASTERN CWA AND AS MUCH AS +24C ALONG OUR WESTERN BOUNDARY WITH
COLORADO FOR SUNDAY. BY MONDAY, THE 850MB ATMOSPHERE WILL WARM TO
NEAR +20C ALONG THE PRATT AND KINGMAN LINE, AND TO THE 24C TO 25C
DEGREE RANGE IN THE WEST NEAR COLORADO. THE WARMEST DAY MAY BE
TUESDAY, ESPECIALLY IN OUR SOUTHWEST CORNER NEAR ELKHART AND
LIBERAL, WHERE TEMPERATURES MAY SOAR INTO THE MIDDLE 80S.
JUST HOW FAST THE COLD FRONT COMES DOWN TUESDAY NIGHT IS HANDLED
DIFFERENTLY BY THE LONG RANGE MODELS. THE GFS IS THE FASTEST, AND
THE ECMWF IS SLOWER. FOR NOW, THE CONSENSUS WAS TO GO WITH THE
SLOWER EC MODEL. EITHER WAY, WEDNESDAY LOOKS CONSIDERABLY COLDER
THAN TUESDAY, BY ABOUT 19F TO 25F DEGREES. FOR BOTH WEDNESDAY AND
THURSDAY, WE WILL BE IN THE GRIP OF A COLD HIGH PRESSURE SYSTEM.
HIGHS WILL ONLY BE IN THE UPPER 50S TO LOWER 60S. THE LOWER LEVEL
FLOW WILL RETURN TO THE SOUTH BY FRIDAY, AND FRIDAY SHOULD WARM TO
THE MID 60S TO LOWER 70S. MINIMUM TEMPERATURES WILL RANGE FROM 45F
TO 55F DEGREES SUNDAY AND MONDAY, FROM 50F TO 60F DEGREES TUESDAY,
AND BACK TO THE 45F TO 55F DEGREE RANGE WEDNESDAY. BOTH THURSDAY
AND FRIDAY MORNINGS LOOK COLD, WITH LOWS DIPPING DOWN INTO THE MID
30S TO NEAR 40F DEGREES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1242 AM CDT SAT APR 27 2013
DENSE FOG IS BECOMING MORE WIDESPREAD ACROSS SOUTHWEST KANSAS EARLY
THIS MORNING. BASED ON THE CURRENT TRENDS AND THE LAST HRRR MODEL AS
WELL AS TRENDS FROM THE LOCAL GFS MOS GUIDANCE, SEVERAL HOURS OF
LIFR/VLIFR VISIBILITIES IN DENSE FOG IS EXPECTED THROUGH SATURDAY
MORNING AT EACH OF THE AREA TERMINALS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 51 82 54 83 / 0 0 10 10
GCK 50 82 53 82 / 0 0 10 0
EHA 50 82 54 83 / 10 0 10 0
LBL 51 82 55 84 / 10 0 10 0
HYS 50 81 54 80 / 0 0 10 10
P28 50 79 56 82 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ030-031-
043>046-063>065-077>079-087-088.
&&
$$
UPDATE...RUSSELL
SHORT TERM...JJOHNSON
LONG TERM...BURKE
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
808 PM EDT SUN APR 28 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN JUST OFFSHORE THROUGH MONDAY...AS LOW
PRESSURE LIFTS NORTHEAST FROM THE MISSISSIPPI VALLEY INTO THE OHIO
VALLEY. THIS AREA OF LOW PRESSURE WILL VERY SLOWLY TRACK ACROSS
THE MID ATLANTIC REGION TONIGHT THROUGH MONDAY NIGHT. LOW PRESSURE
LINGERS OFF THE CAROLINA COAST THROUGH MIDWEEK AS HIGH PRESSURE
REMAINS ANCHORED OVER THE CANADIAN MARITIMES.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
THE LATEST WX ANALYSIS SHOWS ~1028MB SURFACE HIGH WHICH REMAINS
ORIENTED JUST OFF THE MID- ATLANTIC/NORTHEAST COAST. TO THE WEST,
WEAKENING MID/UPPER LEVEL LOW PRESSURE HAS WEAKENED TO AN OPEN
WAVE AS IT CONTINUES TO SLOWLY LIFT NE FROM THE CHICAGOLAND AREA
INTO THE UPPER GREAT LAKES. AREA OF LIGHT RAIN HAS INCREASED ALONG
AND AHEAD OF SLOW MOVING COLD FRONT DRAPED ACROSS THE OH/TN VLY.
CLOSER TO HOME, CLOUD COVER HAS CONTINUED TO THICKEN AND LOWER AS
EXPECTED EARLY THIS AFTN AS EXPECTED, ESPECIALLY ACROSS THE
PIEDMONT. HOWEVER...DESPITE INCREASING CLDS THIS AFTN, THE
INFLUENCE OF THE HIGH ALONG THE EASTERN SEABOARD WILL RESULT IN
PERSISTENT LOW- LEVEL DRY AIR (BELOW 800MB) OVER THE LOCAL AREA
PER FORECAST BUFR SOUNDINGS. GIVEN THIS...WILL DOWNPLAY WIDESPREAD
POPS W/THE USE OF A GENERAL PERSISTENCE FORECAST (WHICH JIVES WELL
WITH RUC DEPICTION OF POPS) FOR THE NEXT FEW HOURS. RAIN CHANCES
HV BEEN BUMPED INTO LKLY RANGE FOR FAR WESTERN PIEDMONT, WITH
SLIGHT CHC/LOW CHANCE POPS FARTHER EAST FOR THE REST OF THE
AFTERNOON.
THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE FROM
YESTERDAY,SO THE MAIN INFLUENCE ON HIGH TEMPERATURES WILL BE
INCREASING CLOUD COVER. THIS HAS HELD MAXIMA LARGELY IN THE
MID/UPPER 60S. EAST OF I-95...TEMPERATURES HV REACHED TO ~70/LOW
70S, AND HAVE EVEN DROPPED OFF SLIGHTLY AS CLDS HV BUILT EAST OVER
THE PAST FEW HRS.
RAIN CHANCES GRADUALLY INCREASE TONIGHT AS UPPER TROUGH
APPROACHES THROUGH LATE TONIGHT. INCREASING SYNOPTIC LIFT WILL
SHUNT A STEADY STREAM OF MOISTURE ADVECTION ACROSS THE AREA
TONIGHT, WHICH DEVELOPS ALONG THE EAST COAST. THIS INCREASE IN PW
IS THE RESULT OF THE APPROACHING TROUGH TO THE WEST AND
AFOREMENTIONED QUASI- STATIONARY HIGH TO THE EAST. THIS MOISTURE
TRANSPORT (GOOD MODEL AGREEMENT IN INCREASING PW VALUES TO ~1.3IN)
WILL OFFSET WEAKENING DYNAMICS AND YIELD A PERIOD OF LIGHT TO
MODERATE PCPN LATE TONIGHT INTO MONDAY MORNING. HAVE
CONTINUED/INCREASED POPS INTO CATEGORICAL RANGE WEST OF THE BAY
AFTER 00Z/8P EDT, WITH RAIN CHANCES INCREASING OVER THE EASTERN
SHORE AFTER 06Z/2AM MONDAY.
FOR LOWS, CLOUDY SKY AND MOISTENING LLVLS SHOULD KEEP HIGHS MILD.
EARLY MORNING LOWS IN THE MID 50S TO NR 60.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH WEDNESDAY/...
BY MONDAY...THE TROUGH AXIS VERY SLOWLY APPROACHES THE WESTERN
PORTION OF THE AREA MONDAY MORNING. STEADY STRATIFORM RAIN TAPERS
TO SOME SHRAS WEST OF I-95 MONDAY AFTN AS THE BEST MOISTURE
TRANSPORT GRADUALLY SHIFTS TOWARD THE COAST. 12Z GFS/NAM EACH
SHUNT OMEGA MAX FROM THE THE EASTERN CAROLINAS ACROSS ATLANTIC
COASTAL AREAS MONDAY AFTERNOON AND EVENING...WHICH MESHES WELL
WITH PROGGED AREA OF UPPER DIVERGENCE. THUS, WILL CONTINUE WITH
50-60 POP DURING THIS TIME FRAME AS RAIN CHCS TAPER TO SLIGHT CHC
WEST OF RIC. GIVEN BKN/OVC SKY COVER AND MEAGER INSTABILITY, HAVE
HELD THUNDER OUT OF THE FORECAST FOR NOW. GIVEN CONTINUED
CLOUDINESS, HIGHS REMAIN COOL FOR LATE APRIL...GENERALLY IN THE
UPR 60S TO NR 70, ALTHOUGH AGAIN LOCALLY COOLER ALONG IMMEDIATE
COASTLINES IN ONSHORE FLOW.
THE MID-LEVEL TROUGH AXIS PIVOTS OFF THE COAST LATE MONDAY NIGHT
AND TUESDAY WITH THE ASSOCIATED FLOW BECOMING NW (ALBEIT WEAK).
HIGH PRESSURE REMAINS TO THE NORTHEAST...AND A WEAK REMNANT LOW
LINGERS OFF THE COAST. THIS WILL ALLOW ONSHORE FLOW TO
PERSIST...WHICH SHOULD MAINTAIN CLOUD COVER ALONG WITH SLIGHT
CHANCE/LOW END CHANCE POPS DURING THIS TIME PERIOD.
HIGHS MONDAY SHOULD BE IN THE LOW/MID 60S DUE TO CLOUD COVER AND
SHOWERS. LOWS MONDAY MORNING SHOULD BE IN THE 50S. HIGHS TUESDAY ARE
FORECAST TO RANGE FROM THE MID 60S TO AROUND 70...WHICH IS BELOW
STATISTICAL GUIDANCE DUE TO EXPECTED CLOUD COVER.
TUESDAY/WEDNESDAY...
MID/UPPER LEVEL FLOW FLATTENS OUT/BECOMES QUASI-ZONAL ON TUESDAY.
THE RESULTANT MODEST DRYING ALOFT SHOULD RESULT IN A FAR DRIER DAY
ON TUESDAY. HOWEVER, STILL CANNOT TOTALLY REMOVE POPS WITH
LINGERING MOISTURE PRESENT IN LOW LEVELS PER MODEL CROSS SECTIONS.
THUS, WL RETAIN A 20-30 POP FOR SOME DIURNALLY DRIVEN SHRAS
TUESDAY AFTN/ERY EVE. FOR TEMPERATURES, FORECAST MAXIMA JUST A BIT
BELOW GUIDANCE GIVEN CONTINUED CLOUD COVER, WITH TEMPS INTO THE
LOW/MID 70S EXPECTED. EARLY MORNING LOWS GENERALLY IN THE MID TO
UPPER 50S.
DRIER ON WEDNESDAY COURTESY OF BUILDING MID-UPR RIDGING ALOFT
(COURTESY OF DEVELOPING UPPER TROUGH UPSTREAM ACROSS THE
INTERMOUNTAIN WEST). GIVEN CONTINUED MOIST LLVLS W/ONSHORE FLOW,
WL RETAIN A LOW POP FOR NOW. OTHERWISE, LOOK FOR HIGHS IN THE UPR
60S TO LOW 70S UNDER A PARTLY TO MOSTLY CLOUDY SKY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
PCPN WILL CONTINUE TO SPREAD SLOWLY EAST ACRS THE TAF SITES DURING
SUNDAY EVENING. CEILINGS START OUT AROUND 10K FT AND LOWER SLOWLY
OVERNIGHT AS LOW LEVELS BECOME MOIST. VSBYS REMAIN 7 MILES OR HIGHER
FOR SEVERAL HOURS AFTER PCPN ONSET DUE TO RELATIVELY LOW RH AT
SFC. PCPN INCREASES DURING THE EARLY MORNING HOURS AND CONTINUES
MONDAY.
THERE IS HIGH CONFIDENCE FOR MVFR CONDS BY THE EARLY MORNING HOURS
BUT LOW CONFIDENCE FOR IFR DURING THE TAF PERIOD. SREF ONLY HAS RIC
WITH SIGNIFICANT CHCS FOR IFR WITH VERY LOW PROBS AT PHF ORF AND
ECG. CIGS HAVE A BETTER CHC FOR IFR THAN VSBY ACCORDING TO MOS.
INCLUDED IFR VSBY ONLY AT RIC AND IFR CIGS AT ALL BUT ECG SOMETIME
MONDAY.
OUTLOOK...CHCS FOR IFR ACRS THE TAF SITES INCREASE BEYOND THIS TAF
PERIOD...MAINLY DURING OVERNIGHT THROUGH MID MORNING HOURS. PCPN
CHCS WILL BE FAIRLY LOW BEGINNING TUESDAY.
&&
.MARINE...
SFC HIGH PRESSURE WILL REMAIN STATIONARY OFF THE MID-ATLANTIC COAST
THIS EVENING LEADING TO ONSHORE FLOW AROUND 10 KT. WAVES OVER THE
BAY GENERALLY 2 FT AND SEAS OVER COASTAL WATERS 3-4 FT. LOW PRESSURE
MOVES THRU THE OHIO VALLEY TONIGHT WITH SOUTHERLY WINDS INCREASING
TO 10-15 KT OVER THE WATERS. THE LOW WEAKENS AS IT APPROACHES THE
WATERS MONDAY. HOWEVER...A TIGHT GRADIENT OVER THE WATERS WITH
STRONG HIGH PRESSURE STILL OFFSHORE WILL ALLOW FOR 15-20 KT
SOUTHERLY WINDS OVER THE BAY AND 20-25 KT OVER THE COASTAL WATERS
WITH SEAS BUILDING TO 5-6 FT. SCA`S REMAIN IN PLACE FOR ALL THE
COASTAL WATERS BEGINNING 6-10 AM MONDAY AND CONTINUING THROUGH
MONDAY NIGHT AND HAVE BEEN RAISED FOR ALL BAY ZONES INCLUDING THE
CURRITUCK SOUND STARTING 7 AM THROUGH 7 PM. SMALL CRAFT CONDITIONS
WILL COME DOWN ON THE BAY/SOUND AS THE PRESSURE GRADIENT BEGINS TO
RELAX MON EVENING. SFC HIGH PRESSURE REMAINS LOCKED IN PLACE OVER
THE NEW ENGLAND COAST THRU THE COMING WEEK ALLOWING FOR PERSISTENT
E-NE WINDS OVER THE LOCAL WATERS. ALTHOUGH WINDS WILL LIKELY REMAIN
SUB-SCA DURING THIS TIME...SEAS WILL REMAIN AOA 5 FT SO SCA`S WILL
LIKELY CONTINUE FOR THE ENTIRE WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 7 PM EDT MONDAY FOR
ANZ630>634.
SMALL CRAFT ADVISORY FROM 10 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ650-652-654.
SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 6 AM EDT TUESDAY FOR
ANZ656-658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...AJZ/MAM
LONG TERM...MAS
AVIATION...LSA
MARINE...JDM/DAP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
816 PM EDT SUN APR 28 2013
.UPDATE...
ISSUED AT 811 PM EDT SUN APR 28 2013
ADDED A SCHC FOR TS OVER THE FAR WRN CWA THIS EVNG TO ACCOUNT FOR
RATHER NARROW LINE OF CONVECTION TAKING SHAPE IN NW WI IN ADVANCE
OF HIER H85 DEWPTS/SSI DOWN TO -1C TO -2C. DRY LLVL AIR WITH INVERTED
V LLVL TEMP/DEWPT PROFILES EVIDENT ON RUC ANALYSIS SDNGS SUG ANY PCPN
WL BE RELATIVELY LGT AND NOT EXACERBATE SN MELT RUNOFF. AS THIS LINE
PRESSES FARTHER TO THE E...EXPECT THE CONVECTION TO WEAKEN WITH ONSET
OF NOCTURNAL COOLING AND AS THE CONVECTION RUNS INTO DRIER ANTECEDENT
AIRMASS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 402 PM EDT SUN APR 28 2013
UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW OVER ILLINOIS WITH
AN ASSOCIATED TROUGH. UPPER FLOW ACROSS THE NORTHERN U.S. IS FAIRLY
ZONAL WITH A MINOR SHORTWAVE OVER EASTERN MT THIS MORNING. THIS
SHORTWAVE MOVES INTO THE AREA TONIGHT AND EXITS THE AREA MON
AFTERNOON. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING
THROUGH ALONG WITH DEEPER MOISTURE TONIGHT INTO MONDAY. GFS AND
ECMWF SHOW ABOUT THE SAME THING.
MOISTURE IS PRETTY LIMITED WITH THIS SYSTEM AND SEE A NARROW BAND OF
PCPN MOVING THROUGH TONIGHT INTO MON WITH THE BAND GETTING HUNG UP
OVER THE EAST LATER IN THE DAY. WITH LIMITED MOISTURE...DO NOT WANT
TO GO MORE THAN LIKELY POPS OR HIGH CHANCE AS THIS BAND SLOWLY MOVES
THROUGH THE AREA. QPF AMOUNTS UP TO 0.30 INCH WITH THIS EVENT SEEM
REASONABLE. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST EXCEPT TO DRY THE WEST OUT A BIT FOR MONDAY AS FRONTAL ZONE
IS ALREADY EAST OF THEM BY AFTERNOON. DID NOT MAKE TOO MANY CHANGES
TO TEMPERATURES EITHER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 402 PM EDT SUN APR 28 2013
AFTER A BRIEF PERIOD OF ZONAL FLOW AND A TASTE OF SPRING...UPPER
HEIGHT PATTERN BECOMES MORE AMPLIFIED BY MID WEEK AS TROUGH DEEPENS
OVER WESTERN CANADA AND RIDGING BUILDS FROM THE LOWER GREAT LAKES
TO EASTERN CANADA. BY LATE WEEK...MODELS INDICATE CUTOFF LOW FORMING
OVER THE CNTRL CONUS. LOW PRESSURE TROUGH MOVES THROUGH EARLY IN THE
WEEK...THEN STALLS OUT JUST TO THE EAST OF UPR GREAT LAKES. BOUNDARY
WILL STAY CLOSE ENOUGH TO UPR MICHIGAN TO RESULT IN CHANCES OF PRECIP
THROUGH THE REST OF THE WEEK.
SFC FRONT ON MONDAY EVENING SHOULD BE JUST TO EAST AND SOUTH OF CWA.
SECONDARY SHORTWAVE MOVING THROUGH IN WSW FLOW ALOFT OUT AHEAD OF
LARGER SCALE TROUGHING TO THE WEST COULD HELP TO DEVELOP MORE
SHOWERS PROBABLY CLOSER TO THE SFC BOUNDARY. HIGHER H85 DWPNTS
LIKELY WILL BE INTERCEPTED BY SFC BOUNDARY OVER NORTHEAST WI TO
ACROSS LK MICHIGAN AND NORTHERN LOWER MICHIGAN. ADVECTION OF THE
MOISTURE THEN LIFTS ACROSS EASTERN HALF OF UPR MICHIGAN THROUGH THE
NIGHT.
LARGER SHORTWAVE/MID-UPPER LEVEL JET STREAK PUSHES ACROSS NORTHERN
PLAINS LATER MONDAY NIGHT AND ACROSS NORTHERN MINNESOTA AND WESTERN
LK SUPERIOR TUESDAY INTO TUESDAY EVENING. MODELS DIFFER ON WHICH
PART OF WAVE IS STRONGER...AND THUS ARE DIFFERENT ON PRIMARY SFC LOW
PLACEMENT. GFS/GEM-NH SHOW A NORTHERN LOW TRACK ALONG MINNESOTA AND
ONTARIO BORDER WHILE ECMWF AND NAM INDICATE DOUBLE BARRELLED LOW
FROM MINNESOTA/ONTARIO AND INTO CENTRAL MINNESOTA. YET...MODELS ALL
SHOW COLD FRONT INTO CNTRL UPR MICHIGAN AROUND 00Z ON WEDNESDAY.
DIFFERNCE MAY IMPACT POTENTIAL FOR CLOUDS AND PRECIP WORKING ACROSS
WESTERN HALF OF UPR MICHIGAN DURING THE FIRST PART OF THE DAY...
WHICH AFFECTS HOW MUCH WARMING WILL BE SEEN AHEAD OF COLD FRONT.
PREFER THE ECMWF/NAM/WPC HAND DRAWN PROG IDEA WITH SECOND SFC LOW
AND POSSIBLE WARM FRONT ACROSS MN/CNTRL WI. SFC-BLYR DWPNTS INTO 50S
WITH THE APPROACHING FRONT ALONG WITH ELEVATED MID-LEVEL LAPSE RATES
SUPPORTS MENTION OF TSRA. BEST CHANCE MID-LATE AFTN WOULD BE OVER
SOUTHWEST AND SOUTH CENTRAL...WITH CHANCES TUESDAY EVENING MOVING
ACROSS REST OF EASTERN HALF OF UPR MICHIGAN FOLLOWING INSTABILITY
AXIS AND STRONGER H85 WINDS. CURRENT POP FORECAST SHOWS EXPECTED
TRENDS WELL. WILL TRIM BACK POPS/QPF OVER THE NORTHWEST CWA ON
TUESDAY EVENING THOUGH IN WAKE OF FRONT AND INSTABILITY AXIS.
APPEARS GREATEST INSTABILITY ON TUESDAY WILL STAY SOUTH OF AREA
CLOSER TO SFC DWPNTS NEAR 60F. SINCE STRONGER WINDS AT H7/H5/H3 ARE
NORTHWEST...REDUCING DEEP LAYER SHEAR...POTENTIAL FOR ANY SVR STORMS
IS LOW OVR CWA. HOWEVER...H85 DWPNTS OVER 10C AND SFC FRONT RUNNING
PARALLEL TO UPPER HEIGHTS COULD RESULT IN HEAVY DOWNPOURS IN THE
CONVECTIVE ELEMENTS. WILL BE SOMETHING TO WATCH AS ANY HEAVIER RAIN
WOULD ONLY AGGREVATE THE ONGOING SNOWMELT AND RISING RIVER LEVELS.
RIDGING ALOFT CONTINUES BUILDING TUESDAY NIGHT INTO WEDNESDAY OVER
THE LOWER GREAT LAKES. UPPER PATTERN WILL CONTINUE TO SLOW. SFC
FRONT THAT MOVES THROUGH ON TUESDAY EVENING MAY NOT EVEN MAKE IT
EAST OF EASTERN UPR OR NORTHERN LOWER MICHIGAN BY 12Z WEDNESDAY. UPR
LAKES WILL BE ON LEADING SIDE OF LARGER TROUGH AND IN AREA OF UPPER
JET DIVERGENCE/H7-H5 JET WEDNESDAY THROUGH THURSDAY. FEASIBLE THAT
ECMWF/GFS IDEA SHOWING PERSISTENT RIBBON OF QPF THROUGH THURSDAY IS
CORRECT WITH THIS LARGE SCALE SETUP AND SINCE UPPER LAKES IS WITHIN
H85 TROUGH/AXIS OF HIGHER H85 DWPNTS NEAR +10C WITH AT LEAST SOME
AREAS OF H85-H7 FRONTOGENESIS. MAIN QUESTION IS EXACTLY WHERE THIS
NARROW RIBBON OF PRECIP WILL SET UP. CONSENSUS OF GFS/ECMWF POINT
TO WESTERN HALF OF UPR MICHIGAN. EXACT LOCATION AND INTENSITY OF THE
PRECIP WILL BE CRITICAL AS IT WILL BE FALLING OVER BASINS THAT
ALREADY SHOULD BE SEEING FLOODING AT THAT TIME. COLDER TEMPS STILL
APPEAR IN THE OFFING JUST IN WAKE OF THE SHARP H85 TROUGH. SINCE
UPPER PATTERN REMAINS AMPLIFIED AND BLOCKED UP WITH SOMEWHAT OF A
OMEGA BLOCK LOOK FROM CNTRL CONUS INTO THE EASTERN ATLANTIC...HAVE
TO GO WITH ECMWF IDEA OF FARTHER WEST POSITION OF H85 TROUGH AND
LESS COLD AIR INTO UPR LAKES. EVEN WITH ECMWF THERMAL FIELDS...
WESTERN AND NORTH CENTRAL PORTIONS OF UPR MICHIGAN WOULD BE ENOUGH
ON THE COLD SIDE TO SEE MAINLY SNOW THURSDAY NIGHT INTO FRIDAY
MORNING. POSSIBLE THAT SOME SNOW ACCUMULATIONS COULD OCCUR OVER
THE HIGHER TERRAIN AREAS.
REST OF THE FORECAST PRETTY UNCERTAIN AS IT WILL ALL DEPEND ON HOW
FAR NORTH CLOSED OFF UPPER LOW MEANDERS NEXT WEEKEND. OVERALL WILL
REMAIN COOL AND UNSETTLED THROUGH THE WEEKEND AND POSSIBLY INTO
EARLY NEXT WEEK AS WELL SINCE THE UPPER LOW ONLY SLOWLY LIFTS OUT OF
THE MIDWEST/GREAT LAKES REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 744 PM EDT SUN APR 28 2013
EXPECT VFR CONDITIONS TO PREVAIL THROUGH THIS EVENING WITH A
RELATIVELY DRY LLVL AIRMASS DOMINATING IN SW FLOW AROUND HIGH
PRESSURE OVER NEW ENGLAND. SOME -SHRA WL ARRIVE AT IWD/CMX AFT 02Z
AHEAD OF AN INCOMING COLD FRONT...BUT LIMITED MSTR RETURN WL LIMIT
PCPN INTENSITY AND THE POTENTIAL FOR CONDITIONS LOWER THAN VFR. NOT
OUT OF THE QUESTION THERE COULD BE SOME TS AT IWD DESPITE THE
LIMITED LLVL MSTR...SO ADDED A CB GROUP TO INDICATE THIS POTENTIAL
FOR THE EVNG. AFTER 06Z...EXPECT ENOUGH LOW LEVEL MOISTENING FOR
MVFR CONDITIONS TO DEVELOP FOLLOWING COLD FROPA. THE ARRIVAL OF HI
PRES AND MUCH DRIER AIR NOW IN THE NRN PLAINS AS WELL AS DAYTIME
HEATING/ MIXING WL ALLOW IMPROVEMENT TO VFR BY MID TO LATE MRNG.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 PM EDT SUN APR 28 2013
WINDS SHOULD STAY BELOW 25KT THROUGH THE PERIOD WITH NO GALES
EXPECTED. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&
.HYDROLOGY...
ISSUED AT 811 PM EDT SUN APR 28 2013
UPDATE...OPTED TO ISSUE FLOOD ADVY FOR THE CHOCOLAY RIVER AT HARVEY
UNTIL TUE AFTN TO ACCOUNT FOR STEEP RISE OF OBSVD WATER LVL AT THAT
SITE. MOST RECENT OB AT 730 PM SHOWED THE LVL AT 9.38 FT...JUST AN
INCH OR TWO BLO BANKFULL. THE UPDATED RFC FCST SHOWS THIS GAUGE
PEAKING AT 9.8 FT MON AFTN...JUST UNDER THE 10.0 FLOOD STAGE. THIS
LATEST FCST SHOWS THE RIVER FALLING BLO BANKFULL TUE AFTN.
ANOTHER DAY IN THE 60S AND 70S HAS KEPT THE MELTING GOING ACROSS THE
CWA. SNOW DEPTHS HAVE FALLEN 15-20 INCHES IN THE LAST WEEK. THE MOST
SNOW REMAINS ON THE GROUND ACROSS NORTHERN UPPER MICHIGAN IN THE
INLAND AND HIGHER TERRAIN AREAS. STILL HAVE TO MELT ANOTHER 12-20
INCHES OF SNOW IN SOME OF THESE AREAS. TROUGH MOVING THROUGH TONIGHT
INTO MONDAY COULD BRING SHOWERS...BUT RAIN AMOUNTS WILL STAY BLO
0.25 INCH. ADDITIONAL RAIN WITH POSSIBLE TSRA MAY OCCUR TUESDAY AS A
COLD FRONT WORKS ACROSS UPR MICHIGAN. HIGHER MOISTURE OVER THE AREA
MAY RESULT IN HEAVY DOWNPOURS WITH ANY THUNDERSTORMS. MUCH COOLER
TEMPERATURES EXPECTED FOR REST OF WEEK BEHIND THE FRONT. ADDITIONAL
CHANCES OF RAIN AND EVEN SNOW WILL ALSO CONTINUE ACROSS UPR MICHIGAN
FOR THE REST OF THE WEEK. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION THAT MAY
OCCUR.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...AND EVENTUALLY
THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. MELTING SCENARIOS
STILL REMAIN THE BIGGEST CONFIDENCE REDUCERS IN RIVER FORECASTS AT
THIS POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE
MELT FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS
WILL LIKELY END UP QUITE A BIT HIGHER. MELT CORRECTION FACTOR
ALREADY WAS INCREASED EARLIER THIS WEEKEND FOR THE MEN RIVER
FORECAST GROUP /RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH
HAS KEPT FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND MODERATE
FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR REPUBLIC/WITCH
LAKE. WFO SURVEY OF THE PESHEKEE RIVER ON SATURDAY REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER ON MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS MAY CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES THROUGH MONDAY. MAIN STEM
RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT OF AREAL
FLOOD PROBLEMS WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. FOR COMPLETE DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND
THE LATEST RIVER FLOOD WATCHES AND WARNINGS /FFAMQT AND FFWMQT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...07
LONG TERM...JLA
AVIATION...KC
MARINE...07
HYDROLOGY...KC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
121 PM CDT SAT APR 27 2013
.UPDATE...
ISSUED AT 1001 AM CDT SAT APR 27 2013
MADE SOME UPDATES TO THE FORECAST TODAY...PRIMARILY TO INCREASE
POPS AND LOWER TEMPERATURES A BIT STRETCHING FROM CENTRAL MISSOURI
THROUGH SOUTHWEST ILLINOIS. UPPER LEVEL LOW IS MOVING SLOWLY INTO
WESTERN MISSOURI AND A BROAD AREA OF LIGHT RAIN EXTENDS FROM
SPRINGFIELD MISSOURI UP THROUGH CENTRAL AND EASTERN MISSOURI INTO
SOUTHWEST ILLINOIS. LATEST HRRR GUIDANCE SUGGESTS THIS WILL
PERSIST THROUGH THE DAY AS THE LOW CONTINUES DRIFTING EAST.
CARNEY
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 320 AM CDT SAT APR 27 2013
THE PRIMARY FCST ISSUE FOR TODAY IS PCPN CHCS/COVERAGE ASSOCIATED
WITH A VORT MAX THAT IS SLOWLY PROGRESSING EWD FM OK/KS TOWARDS
MO/IL. THE SFC REFLECTION OF THIS FEATURE IS EXPECTED TO REMAIN
GENERALLY SOUTH OF THE CWA AS IT LIFTS FM OK THROUGH AR INTO SERN
MO. ALTHOUGH THE SFC LOW WILL LIFT A WMFNT NEWD INTO SRN MO...THE
FRONT IS EXPECTED TO REMAIN SOUTH OF THE CWA THEREFORE TEMPERATURES
WILL BE GOVERNED BY CLOUD COVER AND LIMITED DIURNAL HEATING RATHER
THAN BY ADVECTION.
THERE WERE THREE DISTINCT AREAS OF PCPN OCCURRING ACROSS THE REGION
EARLY THIS MORNING. FIRST...A CONVECTIVE COMPLEX WAS MOVING THROUGH
OK INTO WRN AR AT 08Z. THIS COMPLEX WILL REMAIN SOUTH OF THE CWA.
SECOND...A BROKEN AREA OF SHRA WITH ISO TSRA WAS LOCATED OVER SERN
MO AND WAS MOVING INTO SRN IL AND WRN KY. THIS AREA OF PCPN APPEARS
TO BE FORCED BY LLJ MCONV AND WILL CONTINUE TO AFFECT THE SERN PART
OF THE CWA FOR THE NEXT SEVERAL HOURS UNTIL THE LLJ DIMINISHES.
THIRD...A DEFORMATION ZONE HAS DVLPD ACROSS CENTRAL AND ERN KS AS
WELL AS NWRN MO. AS THE UPPER LOW SHIFTS SLOWLY EWD TODAY SO WILL
THE DEFORMATION ZONE AND ITS PCPN. THERE MAY ALSO BE SOME DIURNAL
ENHANCEMENT OF PCPN COVERAGE. NO MODEL IS HANDLING THE DEFORMATION
ZONE VERY WELL THIS MORNING THEREFORE POPS FOR TODAY ARE BASED ON
THE POSITION OF THE CURRENT DEFORMATION ZONE AND THE FCST POSITION
OF THE CLOSED H5 LOW BY 00Z. IN A DEPARTURE FROM THE PREVIOUS
FCST...PCPN IS NOW EXPECTED TO AFFECT THE MIDDLE AND NRN HALF OF THE
CWA MORE THAN THE SRN HALF.
KANOFSKY
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT APR 27 2013
(TONIGHT - SUNDAY)
A LARGELY NEUTRAL LONGWAVE PATTERN OVER NOAM WILL BEGIN TO
TRANSITION TOWARDS A LONGWAVE RIDGE IN THE E AND A TROF IN THE W
LATER ON SUNDAY. THE MOST PROMINENT FEATURE OF THIS PERIOD WILL BE
THE SYSTEM CENTERED OVER SERN KS CONTINUING TO SLOWLY WORK ITS WAY
THRU OUR REGION...AND SLOWLY IT WILL GO. MODELS HAVE TRENDED ABOUT
6-12 HRS SLOWER WITH THE EWD PROGRESSION OF THIS SYSTEM FROM 24HRS
AGO AND SO HAVING IT ONLY MAKE IT THRU ABOUT TWO-THIRDS THRU THE FA
BY SUNDAY/12Z WITH IT FINALLY EXITING WITH MOST OF ITS DYNAMICS BY
18Z. MAIN DYNAMICS WITH THIS SYSTEM...SINCE IT CLOSED OFF EARLIER
TONIGHT...WILL BE ITS ABILITY NOW TO PRODUCE DEFORMATION ZONE PCPN
FOR AREAS FARTHER N. THIS PCPN SHOULD BE FURTHER ENHANCED DIURNALLY
BY COLD CORE NATURE OF LO ALOFT AND WILL LIKELY SEE THESE EFFECTS
EARLY THIS EVENING BEFORE SUN GOES DOWN. STILL...A GOOD PREVIEW OF
WHAT WE WILL SEE TONIGHT CAN BE SEEN IN ERN KS WITH THE CENTER OF
THE UPPER SYSTEM EXPECTED TO TRACK JUST N OF THE I-70 CORRIDOR.
DEFORMATION ZONE PCPN INITIALLY SHUNTED TO THE NRN HALF OF THE FA
THIS EVENING WILL ERODE ON ITS WRN SIDE AND THEN GRADUALLY TILT MORE
N-S ORIENTED BY SUNDAY MORNING AND DO A FINAL SWEEP ACROSS THE ERN
FA/SWRN IL.
CLOUDS WILL ALSO STICK AROUND SUNDAY LONGER THAN ANTICIPATED 24HRS
AGO...AND THIS WILL TAKE A HIT TO MAX TEMPS...ESPECIALLY FOR STL
METRO AND AREAS SE...WHERE THEY HAVE BEEN TRIMMED A CATEGORY OR
TWO...OR IN LINE WITH THE COOLER MET MOS NUMBERS. FURTHER NW...MAX
TEMPS ARE CLOSE TO A MOS BLEND.
(MONDAY - WEDNESDAY)
UPPER LEVEL RIDGE OVER ERN NOAM WILL DOMINATE THIS PERIOD...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE PLAINS BY WEDNESDAY. THIS
SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.
THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY MAX TEMPS AND
IN SOME PLACES...EDGED EVEN HIGHER. LOOK FOR LO-MID 80S ON TUESDAY
WITH A MORE SW WIND EXPECTED. LARGE ADJUSTMENT MADE TO
INITIALIZATION FOR MAX TEMPS ON WEDNESDAY WITH ECMWF CONSISTENTLY
THE SLOWEST MODEL WITH PROGRESSION WHAT SHOULD BE A STRONG CDFNT AND
EVEN GFS ALSO BACKING OFF. WEDNESDAY MAX TEMPS WITH A CDFNT EITHER
ARRIVING VERY LATE OR NOT AT ALL WILL YIELD VALUES AT LEAST
COMPARABLE TO MONDAY...PROBABLY TUESDAY.
(THURSDAY - FRIDAY)
LARGE DISCREPANCY BETWEEN MODELS ON WHAT TO DO NEXT WITH THAT PLAINS
UPPER LEVEL TROF. WHILE ALL BREAK OFF THE DIGGING SHORTWAVE
RESPONSIBLE AND CUT IT OFF FROM THE MAIN FLOW...WHEN AND WHERE THIS
HAPPENS IS A MATTER OF DISPUTE. THE GEM AND ECMWF PREFER TO MAKE
THIS OCCUR SOONER AND SETUP A CUTOFF LO OVER THE CNTRL-SRN PLAINS
WHILE THE GFS IS A BIT LATER...AND INSTEAD OVER THE MID MS AND LOWER
OH VALLEYS. A HUGE DIFFERENCE IN WHAT I FCST DEPENDING ON WHICH
MODEL WITH SFC CDFNT TIMING DIFFS AND AMOUNT OF TIME FRONT SPENDS
OVER THE FA AS WELL...WITH THE GFS BLOWING IT THRU QUICKLY WHILE THE
ECMWF AND GEM LINGER IT FOR A WHILE. WENT GENEROUS WITH POPS ON THE
TAIL-END TIMING-WISE...NOW EXTENDING CHC CATEGORY INTO THURSDAY
NIGHT FOR SOME AREAS ESPECIALLY WITH WEDNESDAY LOOKING LESS
PROBABLE. BUT OVERALL...A LO CONFIDENCE FCST AT THIS TIME. SHOULD
COLD AIR BLOW THRU PER GFS...COULD BE AN UNUSUALLY COLD COUPLE OF
MORNINGS FOR EARLY MAY.
TES
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1249 PM CDT SAT APR 27 2013
UPPER LEVEL DISTURBANCE OVER NORTHWEST MISSOURI WILL CONTINUE
DRIFTING EAST. OCCASIONAL RAIN/SHOWERS WILL CONTINUE ACROSS MOST
OF THE AREA...WITH IFR FLIGHT CONDITIONS PREVAILING FOR MOST OF
THE AFTERNOON ALONG AND SOUTH OF THE I-70 CORRIDOR. CONDITIONS MAY
IMPROVE TEMPORARILY AT TIMES...BUT GENERALLY SPEAKING CIGS WILL
REMAIN AOB 900FT IN THESE AREAS. FURTHER NORTH...CIGS BETWEEN
1000-1900FT WILL PREVAIL WITH OCCASIONAL DIPS INTO IFR TERRITORY.
THE RAIN WILL EVENTUALLY TAPER OFF AND END LATE THIS
EVENING/OVERNIGHT. HOWEVER...WIDESPREAD IFR FLIGHT CONDITIONS WILL
CONTINUE TO PREVAIL...MOST LIKELY ACROSS THE ENTIRE AREA IN IN THE
WAKE OF THE DISTURBANCE.
SPECIFICS FOR KSTL...
DIFFICULT CEILING FORECAST AT LAMBERT. BEEN WATCHING CIGS CREEP UP
OVER THE PAST FEW HOURS...AND WITH RAIN COMING TO A TEMPORARY END
IT APPEARS THAT CIGS MAY STILL POP UP TO 1000FT OR A BIT HIGHER.
REGARDLESS...THE RISE TO MVFR WILL ONLY BE TEMPORARY AS ANOTHER
ROUND OF RAIN WILL AFFECT THE TERMINAL LATER THIS AFTERNOON/EARLY
THIS EVENING. AGAIN...TIMING WILL BE DIFFICULT AS THE AREA OF RAIN
CONTINUES TO CHANGE SIZE AND SHAPE. IFR CONDITIONS SHOULD PREVAIL
THROUGH THE NIGHT INTO SUNDAY MORNING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1012 AM CDT SAT APR 27 2013
.UPDATE...
ISSUED AT 1001 AM CDT SAT APR 27 2013
MADE SOME UPDATES TO THE FORECAST TODAY...PRIMARILY TO INCREASE
POPS AND LOWER TEMPERATURES A BIT STRETCHING FROM CENTRAL MISSOURI
THROUGH SOUTHWEST ILLINOIS. UPPER LEVEL LOW IS MOVING SLOWLY INTO
WESTERN MISSOURI AND A BROAD AREA OF LIGHT RAIN EXTENDS FROM
SPRINGFIELD MISSOURI UP THROUGH CENTRAL AND EASTERN MISSOURI INTO
SOUTHWEST ILLINOIS. LATEST HRRR GUIDANCE SUGGESTS THIS WILL
PERSIST THROUGH THE DAY AS THE LOW CONTINUES DRIFTING EAST.
CARNEY
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 320 AM CDT SAT APR 27 2013
THE PRIMARY FCST ISSUE FOR TODAY IS PCPN CHCS/COVERAGE ASSOCIATED
WITH A VORT MAX THAT IS SLOWLY PROGRESSING EWD FM OK/KS TOWARDS
MO/IL. THE SFC REFLECTION OF THIS FEATURE IS EXPECTED TO REMAIN
GENERALLY SOUTH OF THE CWA AS IT LIFTS FM OK THROUGH AR INTO SERN
MO. ALTHOUGH THE SFC LOW WILL LIFT A WMFNT NEWD INTO SRN MO...THE
FRONT IS EXPECTED TO REMAIN SOUTH OF THE CWA THEREFORE TEMPERATURES
WILL BE GOVERNED BY CLOUD COVER AND LIMITED DIURNAL HEATING RATHER
THAN BY ADVECTION.
THERE WERE THREE DISTINCT AREAS OF PCPN OCCURRING ACROSS THE REGION
EARLY THIS MORNING. FIRST...A CONVECTIVE COMPLEX WAS MOVING THROUGH
OK INTO WRN AR AT 08Z. THIS COMPLEX WILL REMAIN SOUTH OF THE CWA.
SECOND...A BROKEN AREA OF SHRA WITH ISO TSRA WAS LOCATED OVER SERN
MO AND WAS MOVING INTO SRN IL AND WRN KY. THIS AREA OF PCPN APPEARS
TO BE FORCED BY LLJ MCONV AND WILL CONTINUE TO AFFECT THE SERN PART
OF THE CWA FOR THE NEXT SEVERAL HOURS UNTIL THE LLJ DIMINISHES.
THIRD...A DEFORMATION ZONE HAS DVLPD ACROSS CENTRAL AND ERN KS AS
WELL AS NWRN MO. AS THE UPPER LOW SHIFTS SLOWLY EWD TODAY SO WILL
THE DEFORMATION ZONE AND ITS PCPN. THERE MAY ALSO BE SOME DIURNAL
ENHANCEMENT OF PCPN COVERAGE. NO MODEL IS HANDLING THE DEFORMATION
ZONE VERY WELL THIS MORNING THEREFORE POPS FOR TODAY ARE BASED ON
THE POSITION OF THE CURRENT DEFORMATION ZONE AND THE FCST POSITION
OF THE CLOSED H5 LOW BY 00Z. IN A DEPARTURE FROM THE PREVIOUS
FCST...PCPN IS NOW EXPECTED TO AFFECT THE MIDDLE AND NRN HALF OF THE
CWA MORE THAN THE SRN HALF.
KANOFSKY
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT APR 27 2013
(TONIGHT - SUNDAY)
A LARGELY NEUTRAL LONGWAVE PATTERN OVER NOAM WILL BEGIN TO
TRANSITION TOWARDS A LONGWAVE RIDGE IN THE E AND A TROF IN THE W
LATER ON SUNDAY. THE MOST PROMINENT FEATURE OF THIS PERIOD WILL BE
THE SYSTEM CENTERED OVER SERN KS CONTINUING TO SLOWLY WORK ITS WAY
THRU OUR REGION...AND SLOWLY IT WILL GO. MODELS HAVE TRENDED ABOUT
6-12 HRS SLOWER WITH THE EWD PROGRESSION OF THIS SYSTEM FROM 24HRS
AGO AND SO HAVING IT ONLY MAKE IT THRU ABOUT TWO-THIRDS THRU THE FA
BY SUNDAY/12Z WITH IT FINALLY EXITING WITH MOST OF ITS DYNAMICS BY
18Z. MAIN DYNAMICS WITH THIS SYSTEM...SINCE IT CLOSED OFF EARLIER
TONIGHT...WILL BE ITS ABILITY NOW TO PRODUCE DEFORMATION ZONE PCPN
FOR AREAS FARTHER N. THIS PCPN SHOULD BE FURTHER ENHANCED DIURNALLY
BY COLD CORE NATURE OF LO ALOFT AND WILL LIKELY SEE THESE EFFECTS
EARLY THIS EVENING BEFORE SUN GOES DOWN. STILL...A GOOD PREVIEW OF
WHAT WE WILL SEE TONIGHT CAN BE SEEN IN ERN KS WITH THE CENTER OF
THE UPPER SYSTEM EXPECTED TO TRACK JUST N OF THE I-70 CORRIDOR.
DEFORMATION ZONE PCPN INITIALLY SHUNTED TO THE NRN HALF OF THE FA
THIS EVENING WILL ERODE ON ITS WRN SIDE AND THEN GRADUALLY TILT MORE
N-S ORIENTED BY SUNDAY MORNING AND DO A FINAL SWEEP ACROSS THE ERN
FA/SWRN IL.
CLOUDS WILL ALSO STICK AROUND SUNDAY LONGER THAN ANTICIPATED 24HRS
AGO...AND THIS WILL TAKE A HIT TO MAX TEMPS...ESPECIALLY FOR STL
METRO AND AREAS SE...WHERE THEY HAVE BEEN TRIMMED A CATEGORY OR
TWO...OR IN LINE WITH THE COOLER MET MOS NUMBERS. FURTHER NW...MAX
TEMPS ARE CLOSE TO A MOS BLEND.
(MONDAY - WEDNESDAY)
UPPER LEVEL RIDGE OVER ERN NOAM WILL DOMINATE THIS PERIOD...WITH A
TROF BUILDING OVER THE NWRN CONUS INITIALLY...BUT DEEPENING WITH
TIME AS IT SLOWLY TRANSLATES EWD INTO THE PLAINS BY WEDNESDAY. THIS
SHOULD GIVE US A PERIOD OF WARM AND MAINLY DRY WX.
THE WARMER MAV MOS IS A GOOD PLACE TO START FOR MONDAY MAX TEMPS AND
IN SOME PLACES...EDGED EVEN HIGHER. LOOK FOR LO-MID 80S ON TUESDAY
WITH A MORE SW WIND EXPECTED. LARGE ADJUSTMENT MADE TO
INITIALIZATION FOR MAX TEMPS ON WEDNESDAY WITH ECMWF CONSISTENTLY
THE SLOWEST MODEL WITH PROGRESSION WHAT SHOULD BE A STRONG CDFNT AND
EVEN GFS ALSO BACKING OFF. WEDNESDAY MAX TEMPS WITH A CDFNT EITHER
ARRIVING VERY LATE OR NOT AT ALL WILL YIELD VALUES AT LEAST
COMPARABLE TO MONDAY...PROBABLY TUESDAY.
(THURSDAY - FRIDAY)
LARGE DISCREPANCY BETWEEN MODELS ON WHAT TO DO NEXT WITH THAT PLAINS
UPPER LEVEL TROF. WHILE ALL BREAK OFF THE DIGGING SHORTWAVE
RESPONSIBLE AND CUT IT OFF FROM THE MAIN FLOW...WHEN AND WHERE THIS
HAPPENS IS A MATTER OF DISPUTE. THE GEM AND ECMWF PREFER TO MAKE
THIS OCCUR SOONER AND SETUP A CUTOFF LO OVER THE CNTRL-SRN PLAINS
WHILE THE GFS IS A BIT LATER...AND INSTEAD OVER THE MID MS AND LOWER
OH VALLEYS. A HUGE DIFFERENCE IN WHAT I FCST DEPENDING ON WHICH
MODEL WITH SFC CDFNT TIMING DIFFS AND AMOUNT OF TIME FRONT SPENDS
OVER THE FA AS WELL...WITH THE GFS BLOWING IT THRU QUICKLY WHILE THE
ECMWF AND GEM LINGER IT FOR A WHILE. WENT GENEROUS WITH POPS ON THE
TAIL-END TIMING-WISE...NOW EXTENDING CHC CATEGORY INTO THURSDAY
NIGHT FOR SOME AREAS ESPECIALLY WITH WEDNESDAY LOOKING LESS
PROBABLE. BUT OVERALL...A LO CONFIDENCE FCST AT THIS TIME. SHOULD
COLD AIR BLOW THRU PER GFS...COULD BE AN UNUSUALLY COLD COUPLE OF
MORNINGS FOR EARLY MAY.
TES
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1001 AM CDT SAT APR 27 2013
HAVE UPDATED ALL TERMINALS TO LOWER CIGS INTO THE AFTERNOON BASED
ON CONDITIONAL CLIMATOLOGY AND UPSTREAM OBSERVATIONS. FROM CENTRAL
MISSOURI THROUGH THE STL METRO AREA THIS MEANS IFR INTO THE
AFTERNOON. FURTHER NORTH ACROSS NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS CIGS WILL LIKELY STAY BETWEEN 1000-1900FT.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
927 PM CDT SUN APR 28 2013
.UPDATE...
ISSUED AT 927 PM CDT SUN APR 28 2013
AS OF 02Z RADAR DATA FROM KUEX INDICATES NOTHING IN THE WAY OF
PRECIPITATION OVER OUR CWA. WITH THE LOSS OF DIABATIC HEATING FOR
THE DAY AND POTENTIAL INSTABILITY RAPIDLY DROPPING OFF...PER THE
SPC MESO-ANALYSIS PAGE...THE CHANCES OF CONVECTIVE ACTIVITY BEING
REALIZED ACROSS OUR CWA THIS EVENING ARE QUICKLY DWINDLING. GIVEN
ALL THIS...WENT AHEAD AND PULLED THE ~20% POPS WE PREVIOUSLY HAD
GOING ACROSS OUR NORTHEASTERN CWA THROUGH THIS EVENING. POPS
REMAIN INTACT ACROSS OUR NORTHEAST STARTING AFTER 06Z AS THE
SUBTLE MID LEVEL SHORT WAVE ADVANCES OVER PORTIONS OF THE
REGION...BUT CONVECTIVE ACTIVITY IS NOT CURRENTLY ANTICIPATED WITH
ANY PRECIPITATION AFTER 06Z. THE REMAINDER OF THE FORECAST REMAINS
IN GREAT SHAPE...WITH ONLY SUBTLE CHANGES MADE TO HOURLY
TEMPERATURE...WIND...AND DEWPOINT GRIDS TO BETTER REFLECT CURRENT
OBSERVATIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013
PRIMARY FORECAST CONCERN WILL BE SMALL CHANCES FOR THUNDERSTORMS
LATE THIS AFTERNOON AND EVENING IN THE NORTHEAST PART OF THE CWA
AND THEN ANOTHER SMALL CHANCE FOR SHOWERS IN THE NORTH PART OF THE
CWA OVERNIGHT.
UPPER AIR ANALYSIS AND CURRENT WATER VAPOR IMAGERY SHOW AN UPPER
LEVEL TROUGH MOVING ACROSS THE EASTERN THIRD OF THE COUNTRY WHILE
MORE OF A ZONAL FLOW IS NOTED FROM THE PACIFIC NW INTO THE CENTRAL
PLAINS. THERE ARE A COUPLE OF WEAK SHORT WAVES TO DEAL
WITH...ESPECIALLY ONE MOVING INTO MONTANA WHICH COULD PROVIDE SOME
FORCING ACROSS THE NORTHERN PART OF OUR CWA LATER TONIGHT.
AT THE SURFACE...A TROUGH OF LOW PRESSURE WAS JUST MOVING INTO THE
FAR WESTERN PART OF THE CWA BY 19Z. TEMPERATURES HAVE CLIMBED
STEADILY TODAY AND MOST LOCATIONS SHOULD HIT THE 80S BEFORE THE
AFTERNOON IS OUT. DEW POINTS RANGE FROM THE MID TO UPPER 40S EAST OF
THE SURFACE TROUGH...IN THE MID 30S ALONG THE TROUGH AXIS...AND THEN
DIPPING INTO THE MID 20S 50 TO 100 MILES BEHIND THE TROUGH.
REGARDING FIRE WEATHER CONCERNS...RELATIVE HUMIDITIES HAVE FALLEN
NEAR OR BELOW 20 PERCENT IN THE WEST...BUT WINDS SHOULD STAY BELOW
20 MPH IN THAT PART OF OUR CWA AS THE TROUGH AXIS LIES OVER THAT
AREA. BY THE TIME THE WINDS PICK UP AGAIN FROM THE NW...WE SHOULD BE
A FEW HOURS PAST MAX HEATING.
VARIOUS SHORT RANGE MODELS SHOWING SOME DECENT INSTABILITY AHEAD OF
THE SURFACE TROUGH WHICH COULD TRIGGER CONVECTION LATER THIS
AFTERNOON. BOTH THE HRRR AND THE 4KM WRF SHOWING TSTM DEVELOPMENT IN
THE NORTHEAST PART OF THE CWA FROM ROUGHLY 5 PM THROUGH 10 PM. WHILE
BETTER CHANCES SEEM TO BE JUST A LITTLE FURTHER NORTHEAST THAN OUR
CWA...WILL CONTINUE WITH AT LEAST A SLIGHT CHANCE IN OUR NORTHEAST
AS WE COULD CERTAINLY GET CLIPPED.
THE SHORTWAVE NOTED ABOVE SHOULD HAVE MORE OF AN IMPACT AFTER
MIDNIGHT AND CONTINUED THE CHANCE OF SHOWERS MAINLY IN THE
NORTHEASTERN HALF OF THE CWA. FORCING AND MOISTURE NOT OVERLY
IMPRESSIVE AND WILL KEEP POPS FAIRLY LOW. INSTABILITY ALSO DROPS OFF
QUITE A BIT SO WILL KEEP THUNDER MENTION OUT AFTER MIDNIGHT.
QUIET WEATHER EXPECTED ON MONDAY AS WE AWAIT THE APPROACH OF THE
NEXT SYSTEM UPSTREAM. WITH EASTERLY FLOW AT SURFACE...HIGH
TEMPERATURES SHOULD BE JUST A LITTLE BIT COOLER THAN WHAT WE ARE
SEEING TODAY...BUT ALL IN ALL STILL NOT BAD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013
THE WEATHER PATTERN WILL UNDERGO CHANGES DURING THE EXTENDED PERIODS
WITH A TREND TO COOLER SPRING CONDITIONS.
ON MONDAY NIGHT AN UPPER TROUGH DIGS SOUTH ACROSS THE
NORTHWEST/NORTH CENTRAL TIER STATES AND A SFC COLD FRONTAL BOUNDARY
PUSHES SOUTH FM THE DAKOTAS...AND IS EXPECTED TO STRETCH FM
ROUGHLY KOMA TO KPHG TO SOUTH OF KGLD BY 12Z TUESDAY. WITH FRONT
CROSSING MUCH OF OUR NEB CWA OVERNIGHT...CONSIDERED SOME LOW POPS
TOWARD TUESDAY MORNING BUT CHCS APPEAR HIT OR MISS AND WILL CARRY
SILENT POPS FOR NOW. IN GENERAL...MODELS HAVE CONTINUED TO TREND
FASTER WITH FROPA...WITH THE NAM REMAINING FASTER THAN GFS. THE
FARTHER SOUTH FRONTAL POSITION NEAR THE NEB/KS STATELINE OR IN
NORTHERN KANSAS PLACES CHCS FOR AFTN CONVECTION FARTHER SOUTH AS
WELL. DEPENDING ON TIMING/FRONTAL POSITION THERE STILL APPEARS TO
BE A WINDOW OF OPPORTUNITY...ALBEIT A SHRINKING WINDOW...FOR
POTENTIALLY A STRONG/SEVERE TSTMS IN THE LATE AFTN/EVE FOR OUR
SOUTHEAST ZONES. SOME PRESENCE OF ELEVATED INSTABILITY IS
MAINTAINED INTO THE FIRST PART OF THE NIGHT TUESDAY NIGHT WHICH
SHIFTS SOUTH BY WEDNESDAY MORNING. OVERALL PCPN CHCS INCREASE OVERNIGHT
TUESDAY NIGHT ACROSS OUR ENTIRE CWA IN INCREASING ISENTROPIC LIFT
AHEAD OF THE UPPER TROUGH MOVING ONTO THE CENTRAL PLAINS AND IN
PRESENCE OF STRONG MID LEVEL FRONTOGENESIS. MUCH COLDER AIR
ADVECTS SOUTH BEHIND THE FRONTAL BOUNDARY AND THE R/S LINE ACROSS
WESTERN NEBRASKA LOOKS TO EDGE CLOSE TO OUR NW CWA TOWARDS
WEDNESDAY MORNING.
WEDNESDAY IS SHAPING UP TO BE A COLD...WET...BREEZY/WINDY DAY UNDER
INFLUENCE OF UPPER TROUGH MOVING IN WITH THE BETTER CHCS FOR PCPN
EXPECTED IN THE FIRST PART OF THE DAY BEFORE DRIER AIR ADVECTS IN
FOLLOWING MID LEVEL TROUGH...BUT THIS WILL BE DEPENDENT UPON
SYSTEMN TIMING WITH GFS MORE PROGRESSIVE THAN ECMWF.
MODELS CONTINUE TO DEVIATE ON WHERE UPPER LOW WILL CLOSE OFF
THURS NIGHT/FRI DUE TO A BLOCKING RIDGE TO THE EAST. 24HRS AGO
THE 12Z MODELS CLOSED THE LOW ACROSS THE CENTRAL PLAINS...THEN
THE 00Z SUNDAY RUN OF MODELS CLOSED THE LOW IN EASTERN KS/SOUTHERN
MISSOURI...AND NOW THE 12Z GFS RUN CLOSES THE LOW EAST OF THE
MISSOURI RIVER IN IOWA WITH THE POTENTIAL FOR A CUTOFF SYSTEM TO
LIFT AND RETROGRADE TOWARD THE END OF THE WORKWEEK AND INTO THE
FIRST PART OF NEXT WEEKEND. THE 12Z ECMWF IS A LITTLE MORE SIMILAR
TO ITS PREVIOUS RUN INITIALLY WITH THE SYSTEM CLOSING OFF IN
EASTERN KS WITH THE CUTOFF UPPER LOW MEANDERING ACROSS MISSOURI
THRU THE WEEKEND. PCPN CHCS WILL BE DEPENDENT UPON THE UPPER LOW
PRESSURE SYSTEM POSITION AND IT IS JUST TOO EARLY TO PINPOINT THE
BEST CHCS/TIMING JUST YET GIVEN THE VARYING MODEL SOLUTIONS AND
DID NOT DEVIATE MUCH FROM THE EXTENDED INIT. UNDER THE INFLUENCE
OF THE UPPER LOW/TROUGH PATTERN...TEMPERATURES WILL REMAIN COOL WITH HIGHS
MAINLY 50S...AND LOWS IN THE 30S...ALTHOUGH READINGS COULD RECOVER
SOME IF LOW KICKS OUT TOWARD DAY 7. WITH LOWS IN THE 30S WILL NEED
TO CLOSELY MONITOR POTENTIAL FOR FROST/FREEZE AS SPRING HEADLINES
FOR THIS BEGIN MAY 1.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM CDT SUN APR 28 2013
VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS.
INCREASING HIGH LEVEL CLOUDS WILL BE OBSERVED DURING MUCH OF THE
TAF PERIOD...BUT CEILINGS SHOULD NOT DROP MUCH BELOW 15000FT AGL.
THERE IS A SLIGHT CHANCE OF LIGHT RAIN AT THE TERMINAL BETWEEN 06Z
AND 12Z...BUT AT THIS TIME THE PROBABILITY OF MEASURABLE
PRECIPITATION BEING REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO
TH TAF. THE SURFACE WIND WILL START THE TAF PERIOD FROM THE
SOUTH/SOUTHEAST...BUT TRANSITION TO MORE OF A NORTH/NORTHEASTERLY
DIRECTION LATER TONIGHT. THE SURFACE WIND WILL ALSO BE FAIRLY
STRONG TO START THE TAF PERIOD...SUSTAINED NEAR 15KTS AND GUSTING
TO AROUND 20KTS...BUT THE SURFACE WIND SHOULD WEAKEN TO AROUND 6
OR 8KTS DURING THE OVERNIGHT HOURS. VISIBILITY RESTRICTION IS NOT
EXPECTED AT THE TERMINAL THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...BRYANT
SHORT TERM...EWALD
LONG TERM...FAY
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
639 PM CDT SUN APR 28 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013
PRIMARY FORECAST CONCERN WILL BE SMALL CHANCES FOR THUNDERSTORMS
LATE THIS AFTERNOON AND EVENING IN THE NORTHEAST PART OF THE CWA
AND THEN ANOTHER SMALL CHANCE FOR SHOWERS IN THE NORTH PART OF THE
CWA OVERNIGHT.
UPPER AIR ANALYSIS AND CURRENT WATER VAPOR IMAGERY SHOW AN UPPER
LEVEL TROUGH MOVING ACROSS THE EASTERN THIRD OF THE COUNTRY WHILE
MORE OF A ZONAL FLOW IS NOTED FROM THE PACIFIC NW INTO THE CENTRAL
PLAINS. THERE ARE A COUPLE OF WEAK SHORT WAVES TO DEAL
WITH...ESPECIALLY ONE MOVING INTO MONTANA WHICH COULD PROVIDE SOME
FORCING ACROSS THE NORTHERN PART OF OUR CWA LATER TONIGHT.
AT THE SURFACE...A TROUGH OF LOW PRESSURE WAS JUST MOVING INTO THE
FAR WESTERN PART OF THE CWA BY 19Z. TEMPERATURES HAVE CLIMBED
STEADILY TODAY AND MOST LOCATIONS SHOULD HIT THE 80S BEFORE THE
AFTERNOON IS OUT. DEW POINTS RANGE FROM THE MID TO UPPER 40S EAST OF
THE SURFACE TROUGH...IN THE MID 30S ALONG THE TROUGH AXIS...AND THEN
DIPPING INTO THE MID 20S 50 TO 100 MILES BEHIND THE TROUGH.
REGARDING FIRE WEATHER CONCERNS...RELATIVE HUMIDITIES HAVE FALLEN
NEAR OR BELOW 20 PERCENT IN THE WEST...BUT WINDS SHOULD STAY BELOW
20 MPH IN THAT PART OF OUR CWA AS THE TROUGH AXIS LIES OVER THAT
AREA. BY THE TIME THE WINDS PICK UP AGAIN FROM THE NW...WE SHOULD BE
A FEW HOURS PAST MAX HEATING.
VARIOUS SHORT RANGE MODELS SHOWING SOME DECENT INSTABILITY AHEAD OF
THE SURFACE TROUGH WHICH COULD TRIGGER CONVECTION LATER THIS
AFTERNOON. BOTH THE HRRR AND THE 4KM WRF SHOWING TSTM DEVELOPMENT IN
THE NORTHEAST PART OF THE CWA FROM ROUGHLY 5 PM THROUGH 10 PM. WHILE
BETTER CHANCES SEEM TO BE JUST A LITTLE FURTHER NORTHEAST THAN OUR
CWA...WILL CONTINUE WITH AT LEAST A SLIGHT CHANCE IN OUR NORTHEAST
AS WE COULD CERTAINLY GET CLIPPED.
THE SHORTWAVE NOTED ABOVE SHOULD HAVE MORE OF AN IMPACT AFTER
MIDNIGHT AND CONTINUED THE CHANCE OF SHOWERS MAINLY IN THE
NORTHEASTERN HALF OF THE CWA. FORCING AND MOISTURE NOT OVERLY
IMPRESSIVE AND WILL KEEP POPS FAIRLY LOW. INSTABILITY ALSO DROPS OFF
QUITE A BIT SO WILL KEEP THUNDER MENTION OUT AFTER MIDNIGHT.
QUIET WEATHER EXPECTED ON MONDAY AS WE AWAIT THE APPROACH OF THE
NEXT SYSTEM UPSTREAM. WITH EASTERLY FLOW AT SURFACE...HIGH
TEMPERATURES SHOULD BE JUST A LITTLE BIT COOLER THAN WHAT WE ARE
SEEING TODAY...BUT ALL IN ALL STILL NOT BAD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013
THE WEATHER PATTERN WILL UNDERGO CHANGES DURING THE EXTENDED PERIODS
WITH A TREND TO COOLER SPRING CONDITIONS.
ON MONDAY NIGHT AN UPPER TROUGH DIGS SOUTH ACROSS THE
NORTHWEST/NORTH CENTRAL TIER STATES AND A SFC COLD FRONTAL BOUNDARY
PUSHES SOUTH FM THE DAKOTAS...AND IS EXPECTED TO STRETCH FM
ROUGHLY KOMA TO KPHG TO SOUTH OF KGLD BY 12Z TUESDAY. WITH FRONT
CROSSING MUCH OF OUR NEB CWA OVERNIGHT...CONSIDERED SOME LOW POPS
TOWARD TUESDAY MORNING BUT CHCS APPEAR HIT OR MISS AND WILL CARRY
SILENT POPS FOR NOW. IN GENERAL...MODELS HAVE CONTINUED TO TREND
FASTER WITH FROPA...WITH THE NAM REMAINING FASTER THAN GFS. THE
FARTHER SOUTH FRONTAL POSITION NEAR THE NEB/KS STATELINE OR IN
NORTHERN KANSAS PLACES CHCS FOR AFTN CONVECTION FARTHER SOUTH AS
WELL. DEPENDING ON TIMING/FRONTAL POSITION THERE STILL APPEARS TO
BE A WINDOW OF OPPORTUNITY...ALBEIT A SHRINKING WINDOW...FOR
POTENTIALLY A STRONG/SEVERE TSTMS IN THE LATE AFTN/EVE FOR OUR
SOUTHEAST ZONES. SOME PRESENCE OF ELEVATED INSTABILITY IS
MAINTAINED INTO THE FIRST PART OF THE NIGHT TUESDAY NIGHT WHICH
SHIFTS SOUTH BY WEDNESDAY MORNING. OVERALL PCPN CHCS INCREASE OVERNIGHT
TUESDAY NIGHT ACROSS OUR ENTIRE CWA IN INCREASING ISENTROPIC LIFT
AHEAD OF THE UPPER TROUGH MOVING ONTO THE CENTRAL PLAINS AND IN
PRESENCE OF STRONG MID LEVEL FRONTOGENESIS. MUCH COLDER AIR
ADVECTS SOUTH BEHIND THE FRONTAL BOUNDARY AND THE R/S LINE ACROSS
WESTERN NEBRASKA LOOKS TO EDGE CLOSE TO OUR NW CWA TOWARDS
WEDNESDAY MORNING.
WEDNESDAY IS SHAPING UP TO BE A COLD...WET...BREEZY/WINDY DAY UNDER
INFLUENCE OF UPPER TROUGH MOVING IN WITH THE BETTER CHCS FOR PCPN
EXPECTED IN THE FIRST PART OF THE DAY BEFORE DRIER AIR ADVECTS IN
FOLLOWING MID LEVEL TROUGH...BUT THIS WILL BE DEPENDENT UPON
SYSTEMN TIMING WITH GFS MORE PROGRESSIVE THAN ECMWF.
MODELS CONTINUE TO DEVIATE ON WHERE UPPER LOW WILL CLOSE OFF
THURS NIGHT/FRI DUE TO A BLOCKING RIDGE TO THE EAST. 24HRS AGO
THE 12Z MODELS CLOSED THE LOW ACROSS THE CENTRAL PLAINS...THEN
THE 00Z SUNDAY RUN OF MODELS CLOSED THE LOW IN EASTERN KS/SOUTHERN
MISSOURI...AND NOW THE 12Z GFS RUN CLOSES THE LOW EAST OF THE
MISSOURI RIVER IN IOWA WITH THE POTENTIAL FOR A CUTOFF SYSTEM TO
LIFT AND RETROGRADE TOWARD THE END OF THE WORKWEEK AND INTO THE
FIRST PART OF NEXT WEEKEND. THE 12Z ECMWF IS A LITTLE MORE SIMILAR
TO ITS PREVIOUS RUN INITIALLY WITH THE SYSTEM CLOSING OFF IN
EASTERN KS WITH THE CUTOFF UPPER LOW MEANDERING ACROSS MISSOURI
THRU THE WEEKEND. PCPN CHCS WILL BE DEPENDENT UPON THE UPPER LOW
PRESSURE SYSTEM POSITION AND IT IS JUST TOO EARLY TO PINPOINT THE
BEST CHCS/TIMING JUST YET GIVEN THE VARYING MODEL SOLUTIONS AND
DID NOT DEVIATE MUCH FROM THE EXTENDED INIT. UNDER THE INFLUENCE
OF THE UPPER LOW/TROUGH PATTERN...TEMPERATURES WILL REMAIN COOL WITH HIGHS
MAINLY 50S...AND LOWS IN THE 30S...ALTHOUGH READINGS COULD RECOVER
SOME IF LOW KICKS OUT TOWARD DAY 7. WITH LOWS IN THE 30S WILL NEED
TO CLOSELY MONITOR POTENTIAL FOR FROST/FREEZE AS SPRING HEADLINES
FOR THIS BEGIN MAY 1.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 639 PM CDT SUN APR 28 2013
VFR CONDITIONS EXPECTED THROUGH THE NEXT 24 HOURS.
INCREASING HIGH LEVEL CLOUDS WILL BE OBSERVED DURING MUCH OF THE
TAF PERIOD...BUT CEILINGS SHOULD NOT DROP MUCH BELOW 15000FT AGL.
THERE IS A SLIGHT CHANCE OF LIGHT RAIN AT THE TERMINAL BETWEEN 06Z
AND 12Z...BUT AT THIS TIME THE PROBABILITY OF MEASURABLE
PRECIPITATION BEING REALIZED AT KGRI IS TOO LOW FOR INSERTION INTO
TH TAF. THE SURFACE WIND WILL START THE TAF PERIOD FROM THE
SOUTH/SOUTHEAST...BUT TRANSITION TO MORE OF A NORTH/NORTHEASTERLY
DIRECTION LATER TONIGHT. THE SURFACE WIND WILL ALSO BE FAIRLY
STRONG TO START THE TAF PERIOD...SUSTAINED NEAR 15KTS AND GUSTING
TO AROUND 20KTS...BUT THE SURFACE WIND SHOULD WEAKEN TO AROUND 6
OR 8KTS DURING THE OVERNIGHT HOURS. VISIBILITY RESTRICTION IS NOT
EXPECTED AT THE TERMINAL THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...EWALD
LONG TERM...FAY
AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
101 PM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT SAT APR 27 2013
LOW PRESSURE WILL CONTINUE TO TRACK ACROSS SRN CANADA TODAY
PRODUCING SOUTHWEST WINDS AHEAD OF A NORTHWEST WIND SHIFT ACROSS
NORTHWEST NEBRASKA. LIGHT WINDS...DEEP VERTICAL MIXING...NEARLY FULL
SUN AND A STRONG THERMAL RIDGE SHOULD PRODUCE HIGHS AROUND 80. THE
RAP MODEL IS LEADING THE WAY WITH THIS FEATURE.
TONIGHT...WEST WINDS DEVELOP MAINTAINING A THERMAL RIDGE ACROSS THE
FORECAST AREA AND LOWS IN THE 30S TO NEAR 40.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 348 AM CDT SAT APR 27 2013
ANOTHER DAY OF WELL ABOVE
NORMAL TEMPERATURES WILL BE EXPECTED FOR SUNDAY AS GUIDANCE SUGGEST
H85 TEMPERATURES APPROACHING...IF NOT EXCEEDING 20C. THE WARM LOWER
LEVELS WILL ALLOW SURFACE TEMPERATURES TO CLIMB WELL INTO THE
70S...AND POSSIBLY LOW 80S ACROSS THE ENTIRE FORECAST AREA. WITH THE
WELL ABOVE CLIMO HIGHS EXPECTED...FIRE CONCERNS WILL ONCE AGAIN
FLIRT WITH CRITICAL THRESHOLDS BY EARLY AFTERNOON. THE LOWEST RH
READINGS ARE ANTICIPATED ACROSS OUR WESTERN AND SOUTHERN FIRE ZONES
WHERE A EASTWARD ADVANCING SURFACE TROUGH LOW PRESSURE WILL WORK IN
CONCERT WITH STRONG TROPOSPHERIC MIXING TO ALLOW FOR OCCASIONAL
WIND GUSTS AT OR NEAR 20KTS /SLIGHTLY BELOW RFW WIND THRESHOLD/.
WILL HOLD OFF ON ANY FIRE HEADLINE FOR NOW. INTO THE OVERNIGHT A
WEAK PERTURBATION WILL RAPIDLY ADVANCE THROUGH QUASI-ZONAL FLOW AND
BRING A CHANCE OF A SHOWER...OR POSSIBLY A THUNDERSTORM...TO
NORTHERN PORTIONS OF THE CWA. THE OPERATIONAL MODELS INDICATE
ENOUGH OMEGA FOR PRECIPITATION PRODUCTION FOR MUCH OF THE
CWA...HOWEVER BUFR PROXIMITY SOUNDINGS SUGGEST THE LOWER TROPOSPHERE
WILL REMAIN FAIRLY DRY...THUS WILL MAINTAIN SLIGHT TO LOW END CHANCE
POPS ACROSS OUR NORTH OVERNIGHT SUNDAY INTO MONDAY...GENERALLY TIED
TO THE STRONGEST OMEGA AND BEST LOWER LEVEL MOISTURE PROFILES...BUT
LEAVE THE SOUTHERN HALF OF THE CWA MAINLY DRY...WITH ONLY A MENTION
OF SPRINKLES. SIMILAR CONDITIONS ARE EXPECTED FOR MONDAY...WITH THE
POSSIBILITY OF SLIGHTLY WARMER TEMPERATURES AND GREATER GUSTS. RED
FLAG WARNINGS MAY BE NEEDED FOR THE AFTERNOON HOURS. DRY CONDITIONS
WILL PREVAIL INTO EARLY TUESDAY AS A LACK IN KINEMATIC FORCING
RETURNS ONCE AGAIN...HOWEVER PRECIPITATION CHANCES INCREASE DURING
THE AFTERNOON HOURS ON TUESDAY AS A BAROCLINIC ZONE AND ASSOCIATED
SHORTWAVE CROSSES THE REGION. BESIDES THE PRECIPITATION
CHANCES...TEMPERATURES WILL BE MARKEDLY COOLER FOR MIDWEEK BEHIND
THE PASSING FRONT. IN FACT...FREEZE CONCERNS MAY BE REALIZED EARLY
WEDNESDAY AS THE LONGER RANGE SOLUTIONS SUGGEST H85 TEMPERATURES
FALL SOME 20-25C...WHICH WOULD PROVIDE FOR LOWS IN THE UPPER
20S-LOWER 30S AND HIGHS MAINLY IN THE 50S THROUGH MIDWEEK. THE
LONGER RANGE SOLUTION REMAIN IN POOR AGREEMENT AND THUS CONFIDENCE
IS LOW FOR MIDWEEK AND BEYOND...BUT THE GENERAL IDEA REMAINS OF
BROAD CYCLONIC FLOW ACROSS THE CENTRAL CONUS THROUGH THE END OF THE
WORK WEEK...WITH SLOWLY MODERATING TEMPERATURES AND POSSIBLY A
CHANCE AT ADDITIONAL PRECIPITATION. BUT WITH THE LOW CONFIDENCE IN
THE EXTENDED FORECAST...WILL MAINTAIN A DRY FORECAST BEYOND
WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1259 PM CDT SAT APR 27 2013
RIDGE OF HIGH PRESSURE WILL CONTINUE TO DOMINATE THE REGION INTO
SUNDAY WITH CLEAR VFR SKIES. SOUTHWEST WINDS WILL SLOWLY TURN TO
THE WEST THEN NORTHWEST TODAY. THIS AFTERNOON WINDS WILL GUST TO
AROUND 15 KTS...THEN THIS EVENING DECOUPLING WILL RESULT IN LIGHT
WINDS. TOMORROW WINDS WILL ONCE AGAIN COME UP...ALTHOUGH ONLY TO
10 TO 15 KTS IN THE MORNING.
&&
.FIRE WEATHER...
ISSUED AT 348 AM CDT SAT APR 27 2013
A 75 PERCENT BLEND OF THE RAP AND 25 PERCENT OF THE REST OF THE
MODELS PRODUCES RELATIVE HUMIDITY BETWEEN 10 AND 20 PERCENT ACROSS
THE FCST AREA. ALL INDICATIONS ARE WINDS WILL BE WEAK AT LESS THAN
20 MPH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...MASEK
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1229 PM CDT SAT APR 27 2013
.UPDATE...
ISSUED AT 957 AM CDT SAT APR 27 2013
WILL CONTINUE TO SEE SOME AREAS OF FOG LINGERING THIS
MORNING...PRIMARILY ALONG A PHG/HSI/AUH/JYR LINE...WHERE
VISIBILITIES NEAR 1/2 MILE WILL REMAIN POSSIBLE. HOWEVER...WITH
MOST OTHER AUTOMATED SITES/WEB CAMS SHOWING IMPROVING CONDITIONS
AND THE HRRR SUGGESTING WHAT LINGERING FOG THERE IS NOT LASTING
MUCH LONGER...DECIDED TO LET THE HEADLINE EXPIRE AT 10. OTHERWISE
ONLY MINOR TWEAKS MADE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM CDT SAT APR 27 2013
BIGGEST CHALLENGE WILL BE DETERMINING EXTEND AND TIMING OF FOG THIS
MORNING...AND ALSO HIGH TEMPERATURES FOR TODAY.
WE HAPPEN TO BE IN AN AREA OF LOW-LEVEL CONVERGENCE THAT IS HANDLED
FAIRLY WELL BY THE HRRR...BUT NOT AS WELL BY OTHER MODELS...ALTHOUGH
THE LATEST RUN OF THE SREF ENSEMBLE SEEMS TO BE CATCHING UP WITH THE
HRRR. THE HRRR INDICATES THAT IT COULD BE AS LATE AS 10 AM UNTIL WE
CAN GET THE FOG BURNED OFF.
OVERALL...SPLIT FLOW CONTINUES IN THE UPPER LEVELS...WITH OUR CWA IN
BETWEEN...WHICH WHICH WILL LEND TO LIGHT FLOW IN GENERAL. THERE
SHOULD BE ENOUGH SUBSIDENCE TO HELP SCOUR OUT THE STRATUS AND FOG BY
LATE MORNING...WHICH SHOULD GIVE US PLENTY OF SUN BY AFTERNOON.
AREAS TO THE NORTH/WEST WILL WARM THE MOST AND I HAVE INCREASED HIGH
TEMPERATURES IN THESE AREAS FROM THE PREVIOUS FORECAST...WITH
SOUTHEASTERN AREAS A BIT COOLER WHERE STRATUS MIGHT STICK AROUND A
BIT LONGER AND 850 MB TEMPERATURES WILL BE COOLER. I PLACED QUITE A
BIT OF WEIGHT ON HOW MODELS HAVE PERFORMED VERY RECENTLY TO DERIVE
HIGH TEMPERATURES FOR TODAY. WENT CLOSE TO PREVIOUS FORECAST LOW
TEMPERATURES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 535 AM CDT SAT APR 27 2013
THIS 6-DAY PERIOD LOOKS TO FEATURE QUITE A ROLLER COASTER RIDE IN
TEMPERATURES...STARTING OUT WITH A CONTINUATION OF THE ONGOING
VERY MILD STREAK...BUT THEN SETTLING DOWN BELOW NORMAL AGAIN FOR
WEDNESDAY-FRIDAY. UNFORTUNATELY...THERE ARE SUGGESTIONS BY SOME
MODELS...ESPECIALLY THE ECMWF...THAT THIS NEXT BATCH OF COLD COULD
BE QUITE A BIT MORE INTENSE THAN THE CURRENT FORECAST
DEPICTS...AND DARE WE SAY BRING THE POTENTIAL FOR AT LEAST A
RAIN/SNOW MIX TO SOME AREAS. HOWEVER...GIVEN THAT THIS POTENTIALLY
BIG COOL DOWN IS STILL 4+ DAYS AWAY AND UNCERTAINTY REMAINS
PLENTIFUL...HAVE ONLY MADE MINOR DOWNWARD TWEAKS TO PREVIOUS
FORECAST TEMPS FOR NOW...BUT STAY TUNED FOR POTENTIALLY MORE
DRASTIC CHANGES. GIVEN THAT THIS POTENTIAL COLD SNAP WILL OCCUR IN
EARLY MAY...ITS NOW NOT OUT OF THE QUESTION THAT A FROST
ADVISORY/FREEZE WARNING SITUATION MAY UNFOLD SOMETIME DURING THE
WED-FRI TIME FRAME AS WELL...ALTHOUGH A WIDESPREAD HARD KILLING
FREEZE OF 28 DEGREES OR LOWER DOES NOT SEEM EVIDENT AT THIS TIME.
TURNING TO OTHER ELEMENTS OF THE FORECAST...IT STILL LOOKS LIKE
THE TUES AFTERNOON/EVENING TIME FRAME HOLDS COULD HAVE SEVERE
THUNDERSTORM POTENTIAL...ESPECIALLY WITHIN THE SOUTHEAST 1/3 OF
THE CWA. LAST BUT NOT LEAST...WILL HAVE TO KEEP AN EYE SUNDAY
AFTERNOON FOR AT LEAST LIMITED FIRE DANGER...AS DISCUSSED IN A BIT
MORE DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING IN MORE DETAIL WITH SUNDAY/SUNDAY NIGHT...THE VAST
MAJORITY...IF NOT THE ENTIRE CWA SHOULD STAY DRY...WITH THE
DAYTIME HIGHS LIKELY THE WARMEST OF THE ONGOING WARM
STRETCH...WITH MUCH OF THE CWA FORECAST TO BREACH 80 DEGREES FOR
THE FIRST TIME THIS SPRING. ALOFT...VARIOUS MODELS SUCH AS THE 00Z
NAM/GFS/ECMWF ARE IN DECENT AGREEMENT WITH BROAD WEST-NORTHWEST
FLOW...AS ONE MID LEVEL SHORTWAVE DEPARTS EASTWARD THROUGH THE
MIDWEST/OH VALLEY...WHILE THE NEXT BATCH OF LOW AMPLITUDE MID
LEVEL TROUGHS BRUSHES ACROSS THE DAKOTAS/MAINLY NORTHERN NEB ON
SUN NIGHT. THROUGH MOST OF THE DAY...FAIRLY LIGHT WEST-SOUTHWEST
BREEZES AND PLENTY OF SUNSHINE WILL PREVAIL. HOWEVER...BY LATE
AFTERNOON INTO EARLY EVENING...A WEAK COLD FRONT WILL SAG INTO THE
NORTHERN CWA...PUSHED SOUTHWARD BY THE AFOREMENTIONED NORTHERN
PLAINS ENERGY. ALTHOUGH HAVE LEFT OUT ANY PRECIP MENTION...WENT
AHEAD WITH SILENT 10 POPS ACROSS SEVERAL NORTHERN/WESTERN COUNTIES
LATE AFTERNOON INTO THE EVENING NEAR THIS BOUNDARY TO AT LEAST
HINT AT THE VERY LOW POTENTIAL FOR A SHOWER OR WEAK
THUNDERSTORM...ALTHOUGH THE LATEST 4KM WRF-NMM KEEPS ANY PRECIP
POTENTIAL NORTH OF THE CWA...ALTHOUGH THIS BEARS WATCHING. LATE
SUNDAY NIGHT...KEPT A MEASURABLE POP OUT OF THE FORECAST...BUT
EXPANDED THE PREVIOUSLY INTRODUCED CHANCE OF SPRINKLES ACROSS MOST
OF THE NORTHERN 1/3 OF THE CWA...AS A BAND OF MID LEVEL SATURATION
WORKS EASTWARD ACROSS THE REGION IN ASSOCIATION WITH THE PASSING
WEAK WAVE. ALTHOUGH LATER SHIFTS MAY NEED TO CONSIDER ADDING A LOW
MEASURABLE POP FOR THIS ACTIVITY ESPECIALLY FAR NORTH AROUND
ORD/GREELEY...DRY LOW LEVELS STILL SEEM TO SUGGEST THAT SPRINKLES
SHOULD LARGELY SUFFICE. TEMP-WISE...MADE LITTLE CHANGE TO HIGHS
AND LOWS...WITH ALL AREAS TOPPING OUT SOMEWHERE BETWEEN
79-85...AND BOTTOMING OUT IN THE UPPER 40S TO LOW 50S SUNDAY
NIGHT. BASED ON DRY WESTERLY FLOW ESPECIALLY EVIDENT IN THE LAST
FEW NAM RUNS...AFTERNOON DEWPOINTS WERE LOWERED SEVERAL DEGREES
FROM PREVIOUS...THUS PUSHING A GOOD CHUNK OF THE AREA TO 20
PERCENT OR LOWER RELATIVE HUMIDITY FOR A FEW HOURS.
MONDAY/MONDAY NIGHT...HAVE LEFT THIS ENTIRE 24 HOURS PRECIP
MENTION-FREE FOR NOW...ALTHOUGH AS NOTED BY PREVIOUS FORECASTERS
THIS IS NOT NECESSARILY A GUARANTEE FOR ALL AREAS AND WILL BEAR
WATCHING. IN THE MID LEVELS...THE GENERAL STORY INVOLVES THE
AFOREMENTIONED LOW AMPLITUDE SHORTWAVE TROUGH DEPARTING TO THE
EAST...WHILE A STRONGER UPSTREAM DISTURBANCE AND ASSOCIATED UPPER
JET STREAK STARTS TO CARVE A BIT MORE AMPLIFIED TROUGH ACROSS THE
NORTHERN ROCKIES/NORTHERN PLAINS. BREEZES DURING THE DAY WILL
GRADUALLY TURN FROM EASTERLY TO SOUTHERLY IN RESPONSE TO DEEPENING
LOW PRESSURE TO THE NORTHWEST...WITH THE LEADING EDGES OF THE NEXT
COLD FRONT THEN POSSIBLY REACHING THE NORTHWEST CWA BY SUNRISE
TUESDAY MORNING. AS FOR POSSIBLE PRECIP CHANCES TO CONSIDER IN
LATER FORECASTS...FOR ONE THERE COULD BE A BRIEF PERIOD OF
LINGERING SPRINKLES RIGHT AWAY IN THE MORNING. SECONDLY...THE
LATEST NAM SUGGESTS ANOTHER BATCH OF SHOWER ACTIVITY COULD BRUSH
NORTHERN COUNTIES VERY LATE MON NIGHT...ALTHOUGH THIS IS NOT WELL-
SUPPORTED BY OTHER SOLUTIONS. LASTLY...ALTHOUGH UNLIKELY...SUPPOSE
ITS NOT COMPLETELY OUT OF THE QUESTION THAT A LATE AFTERNOON
THUNDERSTORM COULD DEVELOP PRIMARILY IN THE SOUTHEAST CWA IN
RESPONSE TO 500-1000 J/KG OF 0-1KM MLCAPE...BUT FORECAST SOUNDINGS
SUGGEST THAT CAPPING AND LACK OF LIFT IN THE WAKE OF THE INITIAL
DEPARTING WAVE SHOULD PRECLUDE THIS SCENARIO. BOTTOM LINE...NO
PRECIP RISK MENTIONED AT THIS TIME. TEMP-WISE...ALTHOUGH STILL
QUITE WARM...SLIGHTLY LESS FAVORABLE MIXING THAN SUNDAY IS
EXPECTED TO KEEP TEMPS VERY SLIGHTLY COOLER...AND HAVE MOST AREAS
TOPPING OUT 77-82.
TUESDAY/TUESDAY NIGHT...AS MENTIONED ABOVE...THE LATE
AFTERNOON/EVENING TIME FRAME HOLDS THE BEST POTENTIAL FOR A ROUND
OF POTENTIALLY SEVERE STORMS MAINLY ACROSS THE SOUTHEAST 1/3 TO
1/2 OF THE CWA...BUT THIS IS ALSO FAR FROM A SURE THING AS SO MUCH
WILL DEPEND ON STILL-UNCERTAIN FRONTAL TIMING. ALOFT...BOTH THE
ECMWF/GFS SOLUTIONS ARE STILL IN PRETTY DECENT AGREEMENT AT THIS
POINT THAT A LARGE SCALE TROUGH AXIS WILL CONTINUE TO AMPLIFY
ALONG AN AXIS FROM THE NORTHERN PLAINS TO CENTRAL ROCKIES...WHILE
IN THE LOW LEVELS A RATHER HEALTHY COLD FRONT PUSHES SOUTHWARD
ACROSS THE CWA. ALTHOUGH A DECENT CAP SHOULD HOLD CONVECTION AT
BAY UNTIL AT LEAST MID-AFTERNOON...SOMETIME IN THE 21Z-01Z TIME
FRAME IS CURRENTLY EXPECTED TO FEATURE THE DEVELOPMENT OF STORMS
NEAR THE INVADING COLD FRONT...WHICH COULD BECOME SEVERE IN A
LIKELY QUASI-LINEAR FASHION PER THE ECMWF FORECAST OF 1000-1500
J/KG MLCAPE AND MODEST DEEP LAYER SHEAR. AS THE NIGHT WEARS
ON...THE OVERALL THUNDERSTORM INTENSITY SHOULD DIMINISH...BUT
COVERAGE OF WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS WOULD
INCREASE ACROSS NEARLY THE ENTIRE CWA AS A STRONGLY FORCED BAND OF
MID LEVEL CONVERGENCE/FRONTOGENESIS INVADES THE CWA FROM NORTHWEST
TO SOUTHEAST. ENOUGH CONSISTENCY IN THIS SCENARIO FOR TUESDAY
NIGHT EXISTS THAT POPS WERE RAISED INTO LIKELY TERRITORY IN MANY
AREAS. TEMP-WISE...HIGHS TUESDAY WILL BE TRICKY DUE TO UNCERTAINTY
IN THE SPEED OF THE INVADING COLD FRONT...BUT FOR NOW KEPT A
GENERAL RANGE FROM NEAR 70 NORTH TO NEAR 80 SOUTH.
FOR THE WEDNESDAY-FRIDAY TIME FRAME...THERE JUST ISN/T MUCH TO BE
GAINED YET BY GOING INTO MUCH DETAIL DUE TO VARYING MODEL
SOLUTIONS REGARDING THE EVOLUTION OF THE PASSING LARGE SCALE
TROUGH. IN GENERAL...BOTH THE 00Z ECMWF/GFS SOLUTIONS DEPICT A
SLOWING AND STALLING MID/UPPER TROUGH AS IT PASSES INTO THE
CENTRAL PORTION OF THE NATION...AS AN EXPANSIVE BLOCKING RIDGE
SETS UP SHOP OVER THE EASTERN CONUS. AS THIS BLOCK TAKES SHAPE...A
CLOSED...COLD AND FAIRLY COMPACT MID LEVEL LOW IS PROGGED TO FORM
SOMEWHERE...WITH THE ECMWF CLOSING THIS OFF OVER THE KS/OK AREA BY
THURS NIGHT INTO FRIDAY...WHILE THE GFS CLOSES THIS DEEP LOW OFF
MORE SO OVER MO/AR. ABOUT THE ONLY THING THE CURRENT FORECAST HAS
MUCH CONFIDENCE IN IS THAT DECENT PRECIP CHANCES WILL CONTINUE
ACROSS NEARLY THE ENTIRE CWA DURING THE DAY WEDNESDAY. HAVE KEPT
THIS RAIN FOR NOW...BUT THE VERY COLD ECMWF SOLUTION WOULD SUGGEST
A SNOW MIX POSSIBLE. THE CURRENT FORECAST THEN LINGERS A LESSER
CHANCE OF A RAIN/SNOW MIX ACROSS ROUGHLY THE SOUTHEAST 1/3 OF THE
CWA WED NIGHT...WHILE KEEPING THURSDAY-FRIDAY PRECIP-FREE.
HOWEVER...THIS PRECIP-FREE DEPICTION WILL NOT LAST IF THE ECMWF IS
IN FACT ONTO SOMETHING...AS IT DEPICTS A POSSIBLE RAIN/SNOW MIX
LASTING INTO FRIDAY IN SOME AREAS. RE-EMPHASIZING THE MAIN POINTS
HERE...A MUCH COOLER WEATHER REGIME WILL SETTLE IN BY MID-LATE
WEEK...BUT WE ARE STILL A FEW DAYS AWAY FROM PINNING DOWN JUST
HOW COLD IT MIGHT REALLY GET...AND WHETHER A RISK REALLY EXISTS
FOR POSSIBLY ANOTHER ROUND OF LATE-SEASON SNOW AND/OR SUB-
FREEZING OVERNIGHT LOW TEMPS. STAY TUNED...
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM CDT SAT APR 27 2013
QUIET WEATHER WITH VFR CONDITIONS EXPECTED FOR THIS TAF
PERIOD...WITH UPPER LEVEL SHORTWAVE RIDGING BUILDING INTO THE
REGION. EXPECTING LITTLE IN THE WAY OF CLOUD COVER THROUGH THE
PERIOD...AND SOUTH/SOUTHWESTERLY WINDS WILL REMAIN IN
PLACE WITH SPEEDS GENERALLY NEAR 10 MPH.
&&
.FIRE WEATHER...
ISSUED AT 535 AM CDT SAT APR 27 2013
BOTH TODAY AND SUNDAY...THE LATEST FORECASTS NOW PUSH AFTERNOON
RELATIVE HUMIDITY VALUES BELOW 20 PERCENT IN PARTS OF THE CWA.
HOWEVER...THE PRESENCE OF LIGHTER WINDS THAN THOSE OBSERVED FRIDAY
IS CURRENTLY EXPECTED TO KEEP OVERALL FIRE DANGER RATHER
LIMITED...AS OPPOSED TO ELEVATED TO CRITICAL AS MIGHT BE THE CASE
WITH STRONGER WINDS. FOCUSING FIRST ON TODAY...SUB-20 PERCENT
RELATIVE HUMIDITY IS FORECAST TO FOCUS ONLY IN FAR
WESTERN/NORTHERN AREAS...GENERALLY WEST OF A GREELEY-BEAVER CITY
LINE. THEN ON SUNDAY...SUB-20 PERCENT RH IS PROGGED TO DEVELOP
ACROSS MOST COUNTIES WEST OF THE HIGHWAY 281 CORRIDOR. OF THE TWO
AFTERNOONS...SUNDAY BEARS THE MOST WATCHING TO MAKE SURE WINDS
SPEEDS DON/T CREEP HIGHER THAN CURRENTLY FORECAST.
FOR NOW...SUSTAINED WESTERLY SPEEDS AT MOST 10-15 MPH/GUSTS AT
MOST 15-20 MPH ARE FORECAST...KEEPING THINGS 5-10 MPH SHORT OF
POTENTIALLY CRITICAL FIRE THRESHOLDS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ADO
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...ADO
FIRE WEATHER...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1000 AM CDT SAT APR 27 2013
.UPDATE...
ISSUED AT 957 AM CDT SAT APR 27 2013
WILL CONTINUE TO SEE SOME AREAS OF FOG LINGERING THIS
MORNING...PRIMARILY ALONG A PHG/HSI/AUH/JYR LINE...WHERE
VISIBILITIES NEAR 1/2 MILE WILL REMAIN POSSIBLE. HOWEVER...WITH
MOST OTHER AUTOMATED SITES/WEB CAMS SHOWING IMPROVING CONDITIONS
AND THE HRRR SUGGESTING WHAT LINGERING FOG THERE IS NOT LASTING
MUCH LONGER...DECIDED TO LET THE HEADLINE EXPIRE AT 10. OTHERWISE
ONLY MINOR TWEAKS MADE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM CDT SAT APR 27 2013
BIGGEST CHALLENGE WILL BE DETERMINING EXTEND AND TIMING OF FOG THIS
MORNING...AND ALSO HIGH TEMPERATURES FOR TODAY.
WE HAPPEN TO BE IN AN AREA OF LOW-LEVEL CONVERGENCE THAT IS HANDLED
FAIRLY WELL BY THE HRRR...BUT NOT AS WELL BY OTHER MODELS...ALTHOUGH
THE LATEST RUN OF THE SREF ENSEMBLE SEEMS TO BE CATCHING UP WITH THE
HRRR. THE HRRR INDICATES THAT IT COULD BE AS LATE AS 10 AM UNTIL WE
CAN GET THE FOG BURNED OFF.
OVERALL...SPLIT FLOW CONTINUES IN THE UPPER LEVELS...WITH OUR CWA IN
BETWEEN...WHICH WHICH WILL LEND TO LIGHT FLOW IN GENERAL. THERE
SHOULD BE ENOUGH SUBSIDENCE TO HELP SCOUR OUT THE STRATUS AND FOG BY
LATE MORNING...WHICH SHOULD GIVE US PLENTY OF SUN BY AFTERNOON.
AREAS TO THE NORTH/WEST WILL WARM THE MOST AND I HAVE INCREASED HIGH
TEMPERATURES IN THESE AREAS FROM THE PREVIOUS FORECAST...WITH
SOUTHEASTERN AREAS A BIT COOLER WHERE STRATUS MIGHT STICK AROUND A
BIT LONGER AND 850 MB TEMPERATURES WILL BE COOLER. I PLACED QUITE A
BIT OF WEIGHT ON HOW MODELS HAVE PERFORMED VERY RECENTLY TO DERIVE
HIGH TEMPERATURES FOR TODAY. WENT CLOSE TO PREVIOUS FORECAST LOW
TEMPERATURES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 535 AM CDT SAT APR 27 2013
THIS 6-DAY PERIOD LOOKS TO FEATURE QUITE A ROLLER COASTER RIDE IN
TEMPERATURES...STARTING OUT WITH A CONTINUATION OF THE ONGOING
VERY MILD STREAK...BUT THEN SETTLING DOWN BELOW NORMAL AGAIN FOR
WEDNESDAY-FRIDAY. UNFORTUNATELY...THERE ARE SUGGESTIONS BY SOME
MODELS...ESPECIALLY THE ECMWF...THAT THIS NEXT BATCH OF COLD COULD
BE QUITE A BIT MORE INTENSE THAN THE CURRENT FORECAST
DEPICTS...AND DARE WE SAY BRING THE POTENTIAL FOR AT LEAST A
RAIN/SNOW MIX TO SOME AREAS. HOWEVER...GIVEN THAT THIS POTENTIALLY
BIG COOL DOWN IS STILL 4+ DAYS AWAY AND UNCERTAINTY REMAINS
PLENTIFUL...HAVE ONLY MADE MINOR DOWNWARD TWEAKS TO PREVIOUS
FORECAST TEMPS FOR NOW...BUT STAY TUNED FOR POTENTIALLY MORE
DRASTIC CHANGES. GIVEN THAT THIS POTENTIAL COLD SNAP WILL OCCUR IN
EARLY MAY...ITS NOW NOT OUT OF THE QUESTION THAT A FROST
ADVISORY/FREEZE WARNING SITUATION MAY UNFOLD SOMETIME DURING THE
WED-FRI TIME FRAME AS WELL...ALTHOUGH A WIDESPREAD HARD KILLING
FREEZE OF 28 DEGREES OR LOWER DOES NOT SEEM EVIDENT AT THIS TIME.
TURNING TO OTHER ELEMENTS OF THE FORECAST...IT STILL LOOKS LIKE
THE TUES AFTERNOON/EVENING TIME FRAME HOLDS COULD HAVE SEVERE
THUNDERSTORM POTENTIAL...ESPECIALLY WITHIN THE SOUTHEAST 1/3 OF
THE CWA. LAST BUT NOT LEAST...WILL HAVE TO KEEP AN EYE SUNDAY
AFTERNOON FOR AT LEAST LIMITED FIRE DANGER...AS DISCUSSED IN A BIT
MORE DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING IN MORE DETAIL WITH SUNDAY/SUNDAY NIGHT...THE VAST
MAJORITY...IF NOT THE ENTIRE CWA SHOULD STAY DRY...WITH THE
DAYTIME HIGHS LIKELY THE WARMEST OF THE ONGOING WARM
STRETCH...WITH MUCH OF THE CWA FORECAST TO BREACH 80 DEGREES FOR
THE FIRST TIME THIS SPRING. ALOFT...VARIOUS MODELS SUCH AS THE 00Z
NAM/GFS/ECMWF ARE IN DECENT AGREEMENT WITH BROAD WEST-NORTHWEST
FLOW...AS ONE MID LEVEL SHORTWAVE DEPARTS EASTWARD THROUGH THE
MIDWEST/OH VALLEY...WHILE THE NEXT BATCH OF LOW AMPLITUDE MID
LEVEL TROUGHS BRUSHES ACROSS THE DAKOTAS/MAINLY NORTHERN NEB ON
SUN NIGHT. THROUGH MOST OF THE DAY...FAIRLY LIGHT WEST-SOUTHWEST
BREEZES AND PLENTY OF SUNSHINE WILL PREVAIL. HOWEVER...BY LATE
AFTERNOON INTO EARLY EVENING...A WEAK COLD FRONT WILL SAG INTO THE
NORTHERN CWA...PUSHED SOUTHWARD BY THE AFOREMENTIONED NORTHERN
PLAINS ENERGY. ALTHOUGH HAVE LEFT OUT ANY PRECIP MENTION...WENT
AHEAD WITH SILENT 10 POPS ACROSS SEVERAL NORTHERN/WESTERN COUNTIES
LATE AFTERNOON INTO THE EVENING NEAR THIS BOUNDARY TO AT LEAST
HINT AT THE VERY LOW POTENTIAL FOR A SHOWER OR WEAK
THUNDERSTORM...ALTHOUGH THE LATEST 4KM WRF-NMM KEEPS ANY PRECIP
POTENTIAL NORTH OF THE CWA...ALTHOUGH THIS BEARS WATCHING. LATE
SUNDAY NIGHT...KEPT A MEASURABLE POP OUT OF THE FORECAST...BUT
EXPANDED THE PREVIOUSLY INTRODUCED CHANCE OF SPRINKLES ACROSS MOST
OF THE NORTHERN 1/3 OF THE CWA...AS A BAND OF MID LEVEL SATURATION
WORKS EASTWARD ACROSS THE REGION IN ASSOCIATION WITH THE PASSING
WEAK WAVE. ALTHOUGH LATER SHIFTS MAY NEED TO CONSIDER ADDING A LOW
MEASURABLE POP FOR THIS ACTIVITY ESPECIALLY FAR NORTH AROUND
ORD/GREELEY...DRY LOW LEVELS STILL SEEM TO SUGGEST THAT SPRINKLES
SHOULD LARGELY SUFFICE. TEMP-WISE...MADE LITTLE CHANGE TO HIGHS
AND LOWS...WITH ALL AREAS TOPPING OUT SOMEWHERE BETWEEN
79-85...AND BOTTOMING OUT IN THE UPPER 40S TO LOW 50S SUNDAY
NIGHT. BASED ON DRY WESTERLY FLOW ESPECIALLY EVIDENT IN THE LAST
FEW NAM RUNS...AFTERNOON DEWPOINTS WERE LOWERED SEVERAL DEGREES
FROM PREVIOUS...THUS PUSHING A GOOD CHUNK OF THE AREA TO 20
PERCENT OR LOWER RELATIVE HUMIDITY FOR A FEW HOURS.
MONDAY/MONDAY NIGHT...HAVE LEFT THIS ENTIRE 24 HOURS PRECIP
MENTION-FREE FOR NOW...ALTHOUGH AS NOTED BY PREVIOUS FORECASTERS
THIS IS NOT NECESSARILY A GUARANTEE FOR ALL AREAS AND WILL BEAR
WATCHING. IN THE MID LEVELS...THE GENERAL STORY INVOLVES THE
AFOREMENTIONED LOW AMPLITUDE SHORTWAVE TROUGH DEPARTING TO THE
EAST...WHILE A STRONGER UPSTREAM DISTURBANCE AND ASSOCIATED UPPER
JET STREAK STARTS TO CARVE A BIT MORE AMPLIFIED TROUGH ACROSS THE
NORTHERN ROCKIES/NORTHERN PLAINS. BREEZES DURING THE DAY WILL
GRADUALLY TURN FROM EASTERLY TO SOUTHERLY IN RESPONSE TO DEEPENING
LOW PRESSURE TO THE NORTHWEST...WITH THE LEADING EDGES OF THE NEXT
COLD FRONT THEN POSSIBLY REACHING THE NORTHWEST CWA BY SUNRISE
TUESDAY MORNING. AS FOR POSSIBLE PRECIP CHANCES TO CONSIDER IN
LATER FORECASTS...FOR ONE THERE COULD BE A BRIEF PERIOD OF
LINGERING SPRINKLES RIGHT AWAY IN THE MORNING. SECONDLY...THE
LATEST NAM SUGGESTS ANOTHER BATCH OF SHOWER ACTIVITY COULD BRUSH
NORTHERN COUNTIES VERY LATE MON NIGHT...ALTHOUGH THIS IS NOT WELL-
SUPPORTED BY OTHER SOLUTIONS. LASTLY...ALTHOUGH UNLIKELY...SUPPOSE
ITS NOT COMPLETELY OUT OF THE QUESTION THAT A LATE AFTERNOON
THUNDERSTORM COULD DEVELOP PRIMARILY IN THE SOUTHEAST CWA IN
RESPONSE TO 500-1000 J/KG OF 0-1KM MLCAPE...BUT FORECAST SOUNDINGS
SUGGEST THAT CAPPING AND LACK OF LIFT IN THE WAKE OF THE INITIAL
DEPARTING WAVE SHOULD PRECLUDE THIS SCENARIO. BOTTOM LINE...NO
PRECIP RISK MENTIONED AT THIS TIME. TEMP-WISE...ALTHOUGH STILL
QUITE WARM...SLIGHTLY LESS FAVORABLE MIXING THAN SUNDAY IS
EXPECTED TO KEEP TEMPS VERY SLIGHTLY COOLER...AND HAVE MOST AREAS
TOPPING OUT 77-82.
TUESDAY/TUESDAY NIGHT...AS MENTIONED ABOVE...THE LATE
AFTERNOON/EVENING TIME FRAME HOLDS THE BEST POTENTIAL FOR A ROUND
OF POTENTIALLY SEVERE STORMS MAINLY ACROSS THE SOUTHEAST 1/3 TO
1/2 OF THE CWA...BUT THIS IS ALSO FAR FROM A SURE THING AS SO MUCH
WILL DEPEND ON STILL-UNCERTAIN FRONTAL TIMING. ALOFT...BOTH THE
ECMWF/GFS SOLUTIONS ARE STILL IN PRETTY DECENT AGREEMENT AT THIS
POINT THAT A LARGE SCALE TROUGH AXIS WILL CONTINUE TO AMPLIFY
ALONG AN AXIS FROM THE NORTHERN PLAINS TO CENTRAL ROCKIES...WHILE
IN THE LOW LEVELS A RATHER HEALTHY COLD FRONT PUSHES SOUTHWARD
ACROSS THE CWA. ALTHOUGH A DECENT CAP SHOULD HOLD CONVECTION AT
BAY UNTIL AT LEAST MID-AFTERNOON...SOMETIME IN THE 21Z-01Z TIME
FRAME IS CURRENTLY EXPECTED TO FEATURE THE DEVELOPMENT OF STORMS
NEAR THE INVADING COLD FRONT...WHICH COULD BECOME SEVERE IN A
LIKELY QUASI-LINEAR FASHION PER THE ECMWF FORECAST OF 1000-1500
J/KG MLCAPE AND MODEST DEEP LAYER SHEAR. AS THE NIGHT WEARS
ON...THE OVERALL THUNDERSTORM INTENSITY SHOULD DIMINISH...BUT
COVERAGE OF WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS WOULD
INCREASE ACROSS NEARLY THE ENTIRE CWA AS A STRONGLY FORCED BAND OF
MID LEVEL CONVERGENCE/FRONTOGENESIS INVADES THE CWA FROM NORTHWEST
TO SOUTHEAST. ENOUGH CONSISTENCY IN THIS SCENARIO FOR TUESDAY
NIGHT EXISTS THAT POPS WERE RAISED INTO LIKELY TERRITORY IN MANY
AREAS. TEMP-WISE...HIGHS TUESDAY WILL BE TRICKY DUE TO UNCERTAINTY
IN THE SPEED OF THE INVADING COLD FRONT...BUT FOR NOW KEPT A
GENERAL RANGE FROM NEAR 70 NORTH TO NEAR 80 SOUTH.
FOR THE WEDNESDAY-FRIDAY TIME FRAME...THERE JUST ISN/T MUCH TO BE
GAINED YET BY GOING INTO MUCH DETAIL DUE TO VARYING MODEL
SOLUTIONS REGARDING THE EVOLUTION OF THE PASSING LARGE SCALE
TROUGH. IN GENERAL...BOTH THE 00Z ECMWF/GFS SOLUTIONS DEPICT A
SLOWING AND STALLING MID/UPPER TROUGH AS IT PASSES INTO THE
CENTRAL PORTION OF THE NATION...AS AN EXPANSIVE BLOCKING RIDGE
SETS UP SHOP OVER THE EASTERN CONUS. AS THIS BLOCK TAKES SHAPE...A
CLOSED...COLD AND FAIRLY COMPACT MID LEVEL LOW IS PROGGED TO FORM
SOMEWHERE...WITH THE ECMWF CLOSING THIS OFF OVER THE KS/OK AREA BY
THURS NIGHT INTO FRIDAY...WHILE THE GFS CLOSES THIS DEEP LOW OFF
MORE SO OVER MO/AR. ABOUT THE ONLY THING THE CURRENT FORECAST HAS
MUCH CONFIDENCE IN IS THAT DECENT PRECIP CHANCES WILL CONTINUE
ACROSS NEARLY THE ENTIRE CWA DURING THE DAY WEDNESDAY. HAVE KEPT
THIS RAIN FOR NOW...BUT THE VERY COLD ECMWF SOLUTION WOULD SUGGEST
A SNOW MIX POSSIBLE. THE CURRENT FORECAST THEN LINGERS A LESSER
CHANCE OF A RAIN/SNOW MIX ACROSS ROUGHLY THE SOUTHEAST 1/3 OF THE
CWA WED NIGHT...WHILE KEEPING THURSDAY-FRIDAY PRECIP-FREE.
HOWEVER...THIS PRECIP-FREE DEPICTION WILL NOT LAST IF THE ECMWF IS
IN FACT ONTO SOMETHING...AS IT DEPICTS A POSSIBLE RAIN/SNOW MIX
LASTING INTO FRIDAY IN SOME AREAS. RE-EMPHASIZING THE MAIN POINTS
HERE...A MUCH COOLER WEATHER REGIME WILL SETTLE IN BY MID-LATE
WEEK...BUT WE ARE STILL A FEW DAYS AWAY FROM PINNING DOWN JUST
HOW COLD IT MIGHT REALLY GET...AND WHETHER A RISK REALLY EXISTS
FOR POSSIBLY ANOTHER ROUND OF LATE-SEASON SNOW AND/OR SUB-
FREEZING OVERNIGHT LOW TEMPS. STAY TUNED...
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 546 AM CDT SAT APR 27 2013
REDUCED VISIBILITY IS THE BIGGEST CONCERN FOR THE FIRST 4 HOURS OR
SO. DENSE FOG IS CLOSE BY NEAR THE INTERSTATE AND AT THE AURORA
OBSERVATION. I WENT WITH A MIDDLE ROAD AND ANTICIPATED A 1SM
VISIBILITY ALTHOUGH THE TERMINAL HAS NOT DROPPED BELOW MVFR AS OF
THIS AFD. CONFIDENCE IS NOT HIGH FOR VISIBILITY. STRATUS IS
EXPECTED IN ASSOCIATION WITH THE REDUCED VISIBILITY AND SHOULD
BURN OFF BY LATE MORNING. WIND SHOULD REMAIN LIGHT FOR THIS
FORECAST.
&&
.FIRE WEATHER...
ISSUED AT 535 AM CDT SAT APR 27 2013
BOTH TODAY AND SUNDAY...THE LATEST FORECASTS NOW PUSH AFTERNOON
RELATIVE HUMIDITY VALUES BELOW 20 PERCENT IN PARTS OF THE CWA.
HOWEVER...THE PRESENCE OF LIGHTER WINDS THAN THOSE OBSERVED FRIDAY
IS CURRENTLY EXPECTED TO KEEP OVERALL FIRE DANGER RATHER
LIMITED...AS OPPOSED TO ELEVATED TO CRITICAL AS MIGHT BE THE CASE
WITH STRONGER WINDS. FOCUSING FIRST ON TODAY...SUB-20 PERCENT
RELATIVE HUMIDITY IS FORECAST TO FOCUS ONLY IN FAR
WESTERN/NORTHERN AREAS...GENERALLY WEST OF A GREELEY-BEAVER CITY
LINE. THEN ON SUNDAY...SUB-20 PERCENT RH IS PROGGED TO DEVELOP
ACROSS MOST COUNTIES WEST OF THE HIGHWAY 281 CORRIDOR. OF THE TWO
AFTERNOONS...SUNDAY BEARS THE MOST WATCHING TO MAKE SURE WINDS
SPEEDS DON/T CREEP HIGHER THAN CURRENTLY FORECAST.
FOR NOW...SUSTAINED WESTERLY SPEEDS AT MOST 10-15 MPH/GUSTS AT
MOST 15-20 MPH ARE FORECAST...KEEPING THINGS 5-10 MPH SHORT OF
POTENTIALLY CRITICAL FIRE THRESHOLDS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ADO
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...PFANNKUCH
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
625 AM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT SAT APR 27 2013
LOW PRESSURE WILL CONTINUE TO TRACK ACROSS SRN CANADA TODAY
PRODUCING SOUTHWEST WINDS AHEAD OF A NORTHWEST WIND SHIFT ACROSS
NORTHWEST NEBRASKA. LIGHT WINDS...DEEP VERTICAL MIXING...NEARLY FULL
SUN AND A STRONG THERMAL RIDGE SHOULD PRODUCE HIGHS AROUND 80. THE
RAP MODEL IS LEADING THE WAY WITH THIS FEATURE.
TONIGHT...WEST WINDS DEVELOP MAINTAINING A THERMAL RIDGE ACROSS THE
FORECAST AREA AND LOWS IN THE 30S TO NEAR 40.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 348 AM CDT SAT APR 27 2013
ANOTHER DAY OF WELL ABOVE
NORMAL TEMPERATURES WILL BE EXPECTED FOR SUNDAY AS GUIDANCE SUGGEST
H85 TEMPERATURES APPROACHING...IF NOT EXCEEDING 20C. THE WARM LOWER
LEVELS WILL ALLOW SURFACE TEMPERATURES TO CLIMB WELL INTO THE
70S...AND POSSIBLY LOW 80S ACROSS THE ENTIRE FORECAST AREA. WITH THE
WELL ABOVE CLIMO HIGHS EXPECTED...FIRE CONCERNS WILL ONCE AGAIN
FLIRT WITH CRITICAL THRESHOLDS BY EARLY AFTERNOON. THE LOWEST RH
READINGS ARE ANTICIPATED ACROSS OUR WESTERN AND SOUTHERN FIRE ZONES
WHERE A EASTWARD ADVANCING SURFACE TROUGH LOW PRESSURE WILL WORK IN
CONCERT WITH STRONG TROPOSPHERIC MIXING TO ALLOW FOR OCCASIONAL
WIND GUSTS AT OR NEAR 20KTS /SLIGHTLY BELOW RFW WIND THRESHOLD/.
WILL HOLD OFF ON ANY FIRE HEADLINE FOR NOW. INTO THE OVERNIGHT A
WEAK PERTURBATION WILL RAPIDLY ADVANCE THROUGH QUASI-ZONAL FLOW AND
BRING A CHANCE OF A SHOWER...OR POSSIBLY A THUNDERSTORM...TO
NORTHERN PORTIONS OF THE CWA. THE OPERATIONAL MODELS INDICATE
ENOUGH OMEGA FOR PRECIPITATION PRODUCTION FOR MUCH OF THE
CWA...HOWEVER BUFR PROXIMITY SOUNDINGS SUGGEST THE LOWER TROPOSPHERE
WILL REMAIN FAIRLY DRY...THUS WILL MAINTAIN SLIGHT TO LOW END CHANCE
POPS ACROSS OUR NORTH OVERNIGHT SUNDAY INTO MONDAY...GENERALLY TIED
TO THE STRONGEST OMEGA AND BEST LOWER LEVEL MOISTURE PROFILES...BUT
LEAVE THE SOUTHERN HALF OF THE CWA MAINLY DRY...WITH ONLY A MENTION
OF SPRINKLES. SIMILAR CONDITIONS ARE EXPECTED FOR MONDAY...WITH THE
POSSIBILITY OF SLIGHTLY WARMER TEMPERATURES AND GREATER GUSTS. RED
FLAG WARNINGS MAY BE NEEDED FOR THE AFTERNOON HOURS. DRY CONDITIONS
WILL PREVAIL INTO EARLY TUESDAY AS A LACK IN KINEMATIC FORCING
RETURNS ONCE AGAIN...HOWEVER PRECIPITATION CHANCES INCREASE DURING
THE AFTERNOON HOURS ON TUESDAY AS A BAROCLINIC ZONE AND ASSOCIATED
SHORTWAVE CROSSES THE REGION. BESIDES THE PRECIPITATION
CHANCES...TEMPERATURES WILL BE MARKEDLY COOLER FOR MIDWEEK BEHIND
THE PASSING FRONT. IN FACT...FREEZE CONCERNS MAY BE REALIZED EARLY
WEDNESDAY AS THE LONGER RANGE SOLUTIONS SUGGEST H85 TEMPERATURES
FALL SOME 20-25C...WHICH WOULD PROVIDE FOR LOWS IN THE UPPER
20S-LOWER 30S AND HIGHS MAINLY IN THE 50S THROUGH MIDWEEK. THE
LONGER RANGE SOLUTION REMAIN IN POOR AGREEMENT AND THUS CONFIDENCE
IS LOW FOR MIDWEEK AND BEYOND...BUT THE GENERAL IDEA REMAINS OF
BROAD CYCLONIC FLOW ACROSS THE CENTRAL CONUS THROUGH THE END OF THE
WORK WEEK...WITH SLOWLY MODERATING TEMPERATURES AND POSSIBLY A
CHANCE AT ADDITIONAL PRECIPITATION. BUT WITH THE LOW CONFIDENCE IN
THE EXTENDED FORECAST...WILL MAINTAIN A DRY FORECAST BEYOND
WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 623 AM CDT SAT APR 27 2013
VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT. NEARLY FEATURELESS
WEATHER IS EXPECTED AS STORM SYSTEMS TRACK NORTH AND SOUTH OF THE
FCST AREA.
&&
.FIRE WEATHER...
ISSUED AT 348 AM CDT SAT APR 27 2013
A 75 PERCENT BLEND OF THE RAP AND 25 PERCENT OF THE REST OF THE
MODELS PRODUCES RELATIVE HUMIDITY BETWEEN 10 AND 20 PERCENT ACROSS
THE FCST AREA. ALL INDICATIONS ARE WINDS WILL BE WEAK AT LESS THAN
20 MPH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
557 AM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM CDT SAT APR 27 2013
BIGGEST CHALLENGE WILL BE DETERMINING EXTEND AND TIMING OF FOG THIS
MORNING...AND ALSO HIGH TEMPERATURES FOR TODAY.
WE HAPPEN TO BE IN AN AREA OF LOW-LEVEL CONVERGENCE THAT IS HANDLED
FAIRLY WELL BY THE HRRR...BUT NOT AS WELL BY OTHER MODELS...ALTHOUGH
THE LATEST RUN OF THE SREF ENSEMBLE SEEMS TO BE CATCHING UP WITH THE
HRRR. THE HRRR INDICATES THAT IT COULD BE AS LATE AS 10 AM UNTIL WE
CAN GET THE FOG BURNED OFF.
OVERALL...SPLIT FLOW CONTINUES IN THE UPPER LEVELS...WITH OUR CWA IN
BETWEEN...WHICH WHICH WILL LEND TO LIGHT FLOW IN GENERAL. THERE
SHOULD BE ENOUGH SUBSIDENCE TO HELP SCOUR OUT THE STRATUS AND FOG BY
LATE MORNING...WHICH SHOULD GIVE US PLENTY OF SUN BY AFTERNOON.
AREAS TO THE NORTH/WEST WILL WARM THE MOST AND I HAVE INCREASED HIGH
TEMPERATURES IN THESE AREAS FROM THE PREVIOUS FORECAST...WITH
SOUTHEASTERN AREAS A BIT COOLER WHERE STRATUS MIGHT STICK AROUND A
BIT LONGER AND 850 MB TEMPERATURES WILL BE COOLER. I PLACED QUITE A
BIT OF WEIGHT ON HOW MODELS HAVE PERFORMED VERY RECENTLY TO DERIVE
HIGH TEMPERATURES FOR TODAY. WENT CLOSE TO PREVIOUS FORECAST LOW
TEMPERATURES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 535 AM CDT SAT APR 27 2013
THIS 6-DAY PERIOD LOOKS TO FEATURE QUITE A ROLLER COASTER RIDE IN
TEMPERATURES...STARTING OUT WITH A CONTINUATION OF THE ONGOING
VERY MILD STREAK...BUT THEN SETTLING DOWN BELOW NORMAL AGAIN FOR
WEDNESDAY-FRIDAY. UNFORTUNATELY...THERE ARE SUGGESTIONS BY SOME
MODELS...ESPECIALLY THE ECMWF...THAT THIS NEXT BATCH OF COLD COULD
BE QUITE A BIT MORE INTENSE THAN THE CURRENT FORECAST
DEPICTS...AND DARE WE SAY BRING THE POTENTIAL FOR AT LEAST A
RAIN/SNOW MIX TO SOME AREAS. HOWEVER...GIVEN THAT THIS POTENTIALLY
BIG COOL DOWN IS STILL 4+ DAYS AWAY AND UNCERTAINTY REMAINS
PLENTIFUL...HAVE ONLY MADE MINOR DOWNWARD TWEAKS TO PREVIOUS
FORECAST TEMPS FOR NOW...BUT STAY TUNED FOR POTENTIALLY MORE
DRASTIC CHANGES. GIVEN THAT THIS POTENTIAL COLD SNAP WILL OCCUR IN
EARLY MAY...ITS NOW NOT OUT OF THE QUESTION THAT A FROST
ADVISORY/FREEZE WARNING SITUATION MAY UNFOLD SOMETIME DURING THE
WED-FRI TIME FRAME AS WELL...ALTHOUGH A WIDESPREAD HARD KILLING
FREEZE OF 28 DEGREES OR LOWER DOES NOT SEEM EVIDENT AT THIS TIME.
TURNING TO OTHER ELEMENTS OF THE FORECAST...IT STILL LOOKS LIKE
THE TUES AFTERNOON/EVENING TIME FRAME HOLDS COULD HAVE SEVERE
THUNDERSTORM POTENTIAL...ESPECIALLY WITHIN THE SOUTHEAST 1/3 OF
THE CWA. LAST BUT NOT LEAST...WILL HAVE TO KEEP AN EYE SUNDAY
AFTERNOON FOR AT LEAST LIMITED FIRE DANGER...AS DISCUSSED IN A BIT
MORE DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING IN MORE DETAIL WITH SUNDAY/SUNDAY NIGHT...THE VAST
MAJORITY...IF NOT THE ENTIRE CWA SHOULD STAY DRY...WITH THE
DAYTIME HIGHS LIKELY THE WARMEST OF THE ONGOING WARM
STRETCH...WITH MUCH OF THE CWA FORECAST TO BREACH 80 DEGREES FOR
THE FIRST TIME THIS SPRING. ALOFT...VARIOUS MODELS SUCH AS THE 00Z
NAM/GFS/ECMWF ARE IN DECENT AGREEMENT WITH BROAD WEST-NORTHWEST
FLOW...AS ONE MID LEVEL SHORTWAVE DEPARTS EASTWARD THROUGH THE
MIDWEST/OH VALLEY...WHILE THE NEXT BATCH OF LOW AMPLITUDE MID
LEVEL TROUGHS BRUSHES ACROSS THE DAKOTAS/MAINLY NORTHERN NEB ON
SUN NIGHT. THROUGH MOST OF THE DAY...FAIRLY LIGHT WEST-SOUTHWEST
BREEZES AND PLENTY OF SUNSHINE WILL PREVAIL. HOWEVER...BY LATE
AFTERNOON INTO EARLY EVENING...A WEAK COLD FRONT WILL SAG INTO THE
NORTHERN CWA...PUSHED SOUTHWARD BY THE AFOREMENTIONED NORTHERN
PLAINS ENERGY. ALTHOUGH HAVE LEFT OUT ANY PRECIP MENTION...WENT
AHEAD WITH SILENT 10 POPS ACROSS SEVERAL NORTHERN/WESTERN COUNTIES
LATE AFTERNOON INTO THE EVENING NEAR THIS BOUNDARY TO AT LEAST
HINT AT THE VERY LOW POTENTIAL FOR A SHOWER OR WEAK
THUNDERSTORM...ALTHOUGH THE LATEST 4KM WRF-NMM KEEPS ANY PRECIP
POTENTIAL NORTH OF THE CWA...ALTHOUGH THIS BEARS WATCHING. LATE
SUNDAY NIGHT...KEPT A MEASURABLE POP OUT OF THE FORECAST...BUT
EXPANDED THE PREVIOUSLY INTRODUCED CHANCE OF SPRINKLES ACROSS MOST
OF THE NORTHERN 1/3 OF THE CWA...AS A BAND OF MID LEVEL SATURATION
WORKS EASTWARD ACROSS THE REGION IN ASSOCIATION WITH THE PASSING
WEAK WAVE. ALTHOUGH LATER SHIFTS MAY NEED TO CONSIDER ADDING A LOW
MEASURABLE POP FOR THIS ACTIVITY ESPECIALLY FAR NORTH AROUND
ORD/GREELEY...DRY LOW LEVELS STILL SEEM TO SUGGEST THAT SPRINKLES
SHOULD LARGELY SUFFICE. TEMP-WISE...MADE LITTLE CHANGE TO HIGHS
AND LOWS...WITH ALL AREAS TOPPING OUT SOMEWHERE BETWEEN
79-85...AND BOTTOMING OUT IN THE UPPER 40S TO LOW 50S SUNDAY
NIGHT. BASED ON DRY WESTERLY FLOW ESPECIALLY EVIDENT IN THE LAST
FEW NAM RUNS...AFTERNOON DEWPOINTS WERE LOWERED SEVERAL DEGREES
FROM PREVIOUS...THUS PUSHING A GOOD CHUNK OF THE AREA TO 20
PERCENT OR LOWER RELATIVE HUMIDITY FOR A FEW HOURS.
MONDAY/MONDAY NIGHT...HAVE LEFT THIS ENTIRE 24 HOURS PRECIP
MENTION-FREE FOR NOW...ALTHOUGH AS NOTED BY PREVIOUS FORECASTERS
THIS IS NOT NECESSARILY A GUARANTEE FOR ALL AREAS AND WILL BEAR
WATCHING. IN THE MID LEVELS...THE GENERAL STORY INVOLVES THE
AFOREMENTIONED LOW AMPLITUDE SHORTWAVE TROUGH DEPARTING TO THE
EAST...WHILE A STRONGER UPSTREAM DISTURBANCE AND ASSOCIATED UPPER
JET STREAK STARTS TO CARVE A BIT MORE AMPLIFIED TROUGH ACROSS THE
NORTHERN ROCKIES/NORTHERN PLAINS. BREEZES DURING THE DAY WILL
GRADUALLY TURN FROM EASTERLY TO SOUTHERLY IN RESPONSE TO DEEPENING
LOW PRESSURE TO THE NORTHWEST...WITH THE LEADING EDGES OF THE NEXT
COLD FRONT THEN POSSIBLY REACHING THE NORTHWEST CWA BY SUNRISE
TUESDAY MORNING. AS FOR POSSIBLE PRECIP CHANCES TO CONSIDER IN
LATER FORECASTS...FOR ONE THERE COULD BE A BRIEF PERIOD OF
LINGERING SPRINKLES RIGHT AWAY IN THE MORNING. SECONDLY...THE
LATEST NAM SUGGESTS ANOTHER BATCH OF SHOWER ACTIVITY COULD BRUSH
NORTHERN COUNTIES VERY LATE MON NIGHT...ALTHOUGH THIS IS NOT WELL-
SUPPORTED BY OTHER SOLUTIONS. LASTLY...ALTHOUGH UNLIKELY...SUPPOSE
ITS NOT COMPLETELY OUT OF THE QUESTION THAT A LATE AFTERNOON
THUNDERSTORM COULD DEVELOP PRIMARILY IN THE SOUTHEAST CWA IN
RESPONSE TO 500-1000 J/KG OF 0-1KM MLCAPE...BUT FORECAST SOUNDINGS
SUGGEST THAT CAPPING AND LACK OF LIFT IN THE WAKE OF THE INITIAL
DEPARTING WAVE SHOULD PRECLUDE THIS SCENARIO. BOTTOM LINE...NO
PRECIP RISK MENTIONED AT THIS TIME. TEMP-WISE...ALTHOUGH STILL
QUITE WARM...SLIGHTLY LESS FAVORABLE MIXING THAN SUNDAY IS
EXPECTED TO KEEP TEMPS VERY SLIGHTLY COOLER...AND HAVE MOST AREAS
TOPPING OUT 77-82.
TUESDAY/TUESDAY NIGHT...AS MENTIONED ABOVE...THE LATE
AFTERNOON/EVENING TIME FRAME HOLDS THE BEST POTENTIAL FOR A ROUND
OF POTENTIALLY SEVERE STORMS MAINLY ACROSS THE SOUTHEAST 1/3 TO
1/2 OF THE CWA...BUT THIS IS ALSO FAR FROM A SURE THING AS SO MUCH
WILL DEPEND ON STILL-UNCERTAIN FRONTAL TIMING. ALOFT...BOTH THE
ECMWF/GFS SOLUTIONS ARE STILL IN PRETTY DECENT AGREEMENT AT THIS
POINT THAT A LARGE SCALE TROUGH AXIS WILL CONTINUE TO AMPLIFY
ALONG AN AXIS FROM THE NORTHERN PLAINS TO CENTRAL ROCKIES...WHILE
IN THE LOW LEVELS A RATHER HEALTHY COLD FRONT PUSHES SOUTHWARD
ACROSS THE CWA. ALTHOUGH A DECENT CAP SHOULD HOLD CONVECTION AT
BAY UNTIL AT LEAST MID-AFTERNOON...SOMETIME IN THE 21Z-01Z TIME
FRAME IS CURRENTLY EXPECTED TO FEATURE THE DEVELOPMENT OF STORMS
NEAR THE INVADING COLD FRONT...WHICH COULD BECOME SEVERE IN A
LIKELY QUASI-LINEAR FASHION PER THE ECMWF FORECAST OF 1000-1500
J/KG MLCAPE AND MODEST DEEP LAYER SHEAR. AS THE NIGHT WEARS
ON...THE OVERALL THUNDERSTORM INTENSITY SHOULD DIMINISH...BUT
COVERAGE OF WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS WOULD
INCREASE ACROSS NEARLY THE ENTIRE CWA AS A STRONGLY FORCED BAND OF
MID LEVEL CONVERGENCE/FRONTOGENESIS INVADES THE CWA FROM NORTHWEST
TO SOUTHEAST. ENOUGH CONSISTENCY IN THIS SCENARIO FOR TUESDAY
NIGHT EXISTS THAT POPS WERE RAISED INTO LIKELY TERRITORY IN MANY
AREAS. TEMP-WISE...HIGHS TUESDAY WILL BE TRICKY DUE TO UNCERTAINTY
IN THE SPEED OF THE INVADING COLD FRONT...BUT FOR NOW KEPT A
GENERAL RANGE FROM NEAR 70 NORTH TO NEAR 80 SOUTH.
FOR THE WEDNESDAY-FRIDAY TIME FRAME...THERE JUST ISN/T MUCH TO BE
GAINED YET BY GOING INTO MUCH DETAIL DUE TO VARYING MODEL
SOLUTIONS REGARDING THE EVOLUTION OF THE PASSING LARGE SCALE
TROUGH. IN GENERAL...BOTH THE 00Z ECMWF/GFS SOLUTIONS DEPICT A
SLOWING AND STALLING MID/UPPER TROUGH AS IT PASSES INTO THE
CENTRAL PORTION OF THE NATION...AS AN EXPANSIVE BLOCKING RIDGE
SETS UP SHOP OVER THE EASTERN CONUS. AS THIS BLOCK TAKES SHAPE...A
CLOSED...COLD AND FAIRLY COMPACT MID LEVEL LOW IS PROGGED TO FORM
SOMEWHERE...WITH THE ECMWF CLOSING THIS OFF OVER THE KS/OK AREA BY
THURS NIGHT INTO FRIDAY...WHILE THE GFS CLOSES THIS DEEP LOW OFF
MORE SO OVER MO/AR. ABOUT THE ONLY THING THE CURRENT FORECAST HAS
MUCH CONFIDENCE IN IS THAT DECENT PRECIP CHANCES WILL CONTINUE
ACROSS NEARLY THE ENTIRE CWA DURING THE DAY WEDNESDAY. HAVE KEPT
THIS RAIN FOR NOW...BUT THE VERY COLD ECMWF SOLUTION WOULD SUGGEST
A SNOW MIX POSSIBLE. THE CURRENT FORECAST THEN LINGERS A LESSER
CHANCE OF A RAIN/SNOW MIX ACROSS ROUGHLY THE SOUTHEAST 1/3 OF THE
CWA WED NIGHT...WHILE KEEPING THURSDAY-FRIDAY PRECIP-FREE.
HOWEVER...THIS PRECIP-FREE DEPICTION WILL NOT LAST IF THE ECMWF IS
IN FACT ONTO SOMETHING...AS IT DEPICTS A POSSIBLE RAIN/SNOW MIX
LASTING INTO FRIDAY IN SOME AREAS. RE-EMPHASIZING THE MAIN POINTS
HERE...A MUCH COOLER WEATHER REGIME WILL SETTLE IN BY MID-LATE
WEEK...BUT WE ARE STILL A FEW DAYS AWAY FROM PINNING DOWN JUST
HOW COLD IT MIGHT REALLY GET...AND WHETHER A RISK REALLY EXISTS
FOR POSSIBLY ANOTHER ROUND OF LATE-SEASON SNOW AND/OR SUB-
FREEZING OVERNIGHT LOW TEMPS. STAY TUNED...
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 546 AM CDT SAT APR 27 2013
REDUCED VISIBILITY IS THE BIGGEST CONCERN FOR THE FIRST 4 HOURS OR
SO. DENSE FOG IS CLOSE BY NEAR THE INTERSTATE AND AT THE AURORA
OBSERVATION. I WENT WITH A MIDDLE ROAD AND ANTICIPATED A 1SM
VISIBILITY ALTHOUGH THE TERMINAL HAS NOT DROPPED BELOW MVFR AS OF
THIS AFD. CONFIDENCE IS NOT HIGH FOR VISIBILITY. STRATUS IS
EXPECTED IN ASSOCIATION WITH THE REDUCED VISIBILITY AND SHOULD
BURN OFF BY LATE MORNING. WIND SHOULD REMAIN LIGHT FOR THIS
FORECAST.
&&
.FIRE WEATHER...
ISSUED AT 535 AM CDT SAT APR 27 2013
BOTH TODAY AND SUNDAY...THE LATEST FORECASTS NOW PUSH AFTERNOON
RELATIVE HUMIDITY VALUES BELOW 20 PERCENT IN PARTS OF THE CWA.
HOWEVER...THE PRESENCE OF LIGHTER WINDS THAN THOSE OBSERVED FRIDAY
IS CURRENTLY EXPECTED TO KEEP OVERALL FIRE DANGER RATHER
LIMITED...AS OPPOSED TO ELEVATED TO CRITICAL AS MIGHT BE THE CASE
WITH STRONGER WINDS. FOCUSING FIRST ON TODAY...SUB-20 PERCENT
RELATIVE HUMIDITY IS FORECAST TO FOCUS ONLY IN FAR
WESTERN/NORTHERN AREAS...GENERALLY WEST OF A GREELEY-BEAVER CITY
LINE. THEN ON SUNDAY...SUB-20 PERCENT RH IS PROGGED TO DEVELOP
ACROSS MOST COUNTIES WEST OF THE HIGHWAY 281 CORRIDOR. OF THE TWO
AFTERNOONS...SUNDAY BEARS THE MOST WATCHING TO MAKE SURE WINDS
SPEEDS DON/T CREEP HIGHER THAN CURRENTLY FORECAST.
FOR NOW...SUSTAINED WESTERLY SPEEDS AT MOST 10-15 MPH/GUSTS AT
MOST 15-20 MPH ARE FORECAST...KEEPING THINGS 5-10 MPH SHORT OF
POTENTIALLY CRITICAL FIRE THRESHOLDS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ040-041-
046>049-060>064-072>077-082>087.
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ005>007-
017-018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
535 AM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM CDT SAT APR 27 2013
BIGGEST CHALLENGE WILL BE DETERMINING EXTEND AND TIMING OF FOG THIS
MORNING...AND ALSO HIGH TEMPERATURES FOR TODAY.
WE HAPPEN TO BE IN AN AREA OF LOW-LEVEL CONVERGENCE THAT IS HANDLED
FAIRLY WELL BY THE HRRR...BUT NOT AS WELL BY OTHER MODELS...ALTHOUGH
THE LATEST RUN OF THE SREF ENSEMBLE SEEMS TO BE CATCHING UP WITH THE
HRRR. THE HRRR INDICATES THAT IT COULD BE AS LATE AS 10 AM UNTIL WE
CAN GET THE FOG BURNED OFF.
OVERALL...SPLIT FLOW CONTINUES IN THE UPPER LEVELS...WITH OUR CWA IN
BETWEEN...WHICH WHICH WILL LEND TO LIGHT FLOW IN GENERAL. THERE
SHOULD BE ENOUGH SUBSIDENCE TO HELP SCOUR OUT THE STRATUS AND FOG BY
LATE MORNING...WHICH SHOULD GIVE US PLENTY OF SUN BY AFTERNOON.
AREAS TO THE NORTH/WEST WILL WARM THE MOST AND I HAVE INCREASED HIGH
TEMPERATURES IN THESE AREAS FROM THE PREVIOUS FORECAST...WITH
SOUTHEASTERN AREAS A BIT COOLER WHERE STRATUS MIGHT STICK AROUND A
BIT LONGER AND 850 MB TEMPERATURES WILL BE COOLER. I PLACED QUITE A
BIT OF WEIGHT ON HOW MODELS HAVE PERFORMED VERY RECENTLY TO DERIVE
HIGH TEMPERATURES FOR TODAY. WENT CLOSE TO PREVIOUS FORECAST LOW
TEMPERATURES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 535 AM CDT SAT APR 27 2013
THIS 6-DAY PERIOD LOOKS TO FEATURE QUITE A ROLLER COASTER RIDE IN
TEMPERATURES...STARTING OUT WITH A CONTINUATION OF THE ONGOING
VERY MILD STREAK...BUT THEN SETTLING DOWN BELOW NORMAL AGAIN FOR
WEDNESDAY-FRIDAY. UNFORTUNATELY...THERE ARE SUGGESTIONS BY SOME
MODELS...ESPECIALLY THE ECMWF...THAT THIS NEXT BATCH OF COLD COULD
BE QUITE A BIT MORE INTENSE THAN THE CURRENT FORECAST
DEPICTS...AND DARE WE SAY BRING THE POTENTIAL FOR AT LEAST A
RAIN/SNOW MIX TO SOME AREAS. HOWEVER...GIVEN THAT THIS POTENTIALLY
BIG COOL DOWN IS STILL 4+ DAYS AWAY AND UNCERTAINTY REMAINS
PLENTIFUL...HAVE ONLY MADE MINOR DOWNWARD TWEAKS TO PREVIOUS
FORECAST TEMPS FOR NOW...BUT STAY TUNED FOR POTENTIALLY MORE
DRASTIC CHANGES. GIVEN THAT THIS POTENTIAL COLD SNAP WILL OCCUR IN
EARLY MAY...ITS NOW NOT OUT OF THE QUESTION THAT A FROST
ADVISORY/FREEZE WARNING SITUATION MAY UNFOLD SOMETIME DURING THE
WED-FRI TIME FRAME AS WELL...ALTHOUGH A WIDESPREAD HARD KILLING
FREEZE OF 28 DEGREES OR LOWER DOES NOT SEEM EVIDENT AT THIS TIME.
TURNING TO OTHER ELEMENTS OF THE FORECAST...IT STILL LOOKS LIKE
THE TUES AFTERNOON/EVENING TIME FRAME HOLDS COULD HAVE SEVERE
THUNDERSTORM POTENTIAL...ESPECIALLY WITHIN THE SOUTHEAST 1/3 OF
THE CWA. LAST BUT NOT LEAST...WILL HAVE TO KEEP AN EYE SUNDAY
AFTERNOON FOR AT LEAST LIMITED FIRE DANGER...AS DISCUSSED IN A BIT
MORE DETAIL IN THE SEPARATE FIRE WEATHER SECTION BELOW.
STARTING IN MORE DETAIL WITH SUNDAY/SUNDAY NIGHT...THE VAST
MAJORITY...IF NOT THE ENTIRE CWA SHOULD STAY DRY...WITH THE
DAYTIME HIGHS LIKELY THE WARMEST OF THE ONGOING WARM
STRETCH...WITH MUCH OF THE CWA FORECAST TO BREACH 80 DEGREES FOR
THE FIRST TIME THIS SPRING. ALOFT...VARIOUS MODELS SUCH AS THE 00Z
NAM/GFS/ECMWF ARE IN DECENT AGREEMENT WITH BROAD WEST-NORTHWEST
FLOW...AS ONE MID LEVEL SHORTWAVE DEPARTS EASTWARD THROUGH THE
MIDWEST/OH VALLEY...WHILE THE NEXT BATCH OF LOW AMPLITUDE MID
LEVEL TROUGHS BRUSHES ACROSS THE DAKOTAS/MAINLY NORTHERN NEB ON
SUN NIGHT. THROUGH MOST OF THE DAY...FAIRLY LIGHT WEST-SOUTHWEST
BREEZES AND PLENTY OF SUNSHINE WILL PREVAIL. HOWEVER...BY LATE
AFTERNOON INTO EARLY EVENING...A WEAK COLD FRONT WILL SAG INTO THE
NORTHERN CWA...PUSHED SOUTHWARD BY THE AFOREMENTIONED NORTHERN
PLAINS ENERGY. ALTHOUGH HAVE LEFT OUT ANY PRECIP MENTION...WENT
AHEAD WITH SILENT 10 POPS ACROSS SEVERAL NORTHERN/WESTERN COUNTIES
LATE AFTERNOON INTO THE EVENING NEAR THIS BOUNDARY TO AT LEAST
HINT AT THE VERY LOW POTENTIAL FOR A SHOWER OR WEAK
THUNDERSTORM...ALTHOUGH THE LATEST 4KM WRF-NMM KEEPS ANY PRECIP
POTENTIAL NORTH OF THE CWA...ALTHOUGH THIS BEARS WATCHING. LATE
SUNDAY NIGHT...KEPT A MEASURABLE POP OUT OF THE FORECAST...BUT
EXPANDED THE PREVIOUSLY INTRODUCED CHANCE OF SPRINKLES ACROSS MOST
OF THE NORTHERN 1/3 OF THE CWA...AS A BAND OF MID LEVEL SATURATION
WORKS EASTWARD ACROSS THE REGION IN ASSOCIATION WITH THE PASSING
WEAK WAVE. ALTHOUGH LATER SHIFTS MAY NEED TO CONSIDER ADDING A LOW
MEASURABLE POP FOR THIS ACTIVITY ESPECIALLY FAR NORTH AROUND
ORD/GREELEY...DRY LOW LEVELS STILL SEEM TO SUGGEST THAT SPRINKLES
SHOULD LARGELY SUFFICE. TEMP-WISE...MADE LITTLE CHANGE TO HIGHS
AND LOWS...WITH ALL AREAS TOPPING OUT SOMEWHERE BETWEEN
79-85...AND BOTTOMING OUT IN THE UPPER 40S TO LOW 50S SUNDAY
NIGHT. BASED ON DRY WESTERLY FLOW ESPECIALLY EVIDENT IN THE LAST
FEW NAM RUNS...AFTERNOON DEWPOINTS WERE LOWERED SEVERAL DEGREES
FROM PREVIOUS...THUS PUSHING A GOOD CHUNK OF THE AREA TO 20
PERCENT OR LOWER RELATIVE HUMIDITY FOR A FEW HOURS.
MONDAY/MONDAY NIGHT...HAVE LEFT THIS ENTIRE 24 HOURS PRECIP
MENTION-FREE FOR NOW...ALTHOUGH AS NOTED BY PREVIOUS FORECASTERS
THIS IS NOT NECESSARILY A GUARANTEE FOR ALL AREAS AND WILL BEAR
WATCHING. IN THE MID LEVELS...THE GENERAL STORY INVOLVES THE
AFOREMENTIONED LOW AMPLITUDE SHORTWAVE TROUGH DEPARTING TO THE
EAST...WHILE A STRONGER UPSTREAM DISTURBANCE AND ASSOCIATED UPPER
JET STREAK STARTS TO CARVE A BIT MORE AMPLIFIED TROUGH ACROSS THE
NORTHERN ROCKIES/NORTHERN PLAINS. BREEZES DURING THE DAY WILL
GRADUALLY TURN FROM EASTERLY TO SOUTHERLY IN RESPONSE TO DEEPENING
LOW PRESSURE TO THE NORTHWEST...WITH THE LEADING EDGES OF THE NEXT
COLD FRONT THEN POSSIBLY REACHING THE NORTHWEST CWA BY SUNRISE
TUESDAY MORNING. AS FOR POSSIBLE PRECIP CHANCES TO CONSIDER IN
LATER FORECASTS...FOR ONE THERE COULD BE A BRIEF PERIOD OF
LINGERING SPRINKLES RIGHT AWAY IN THE MORNING. SECONDLY...THE
LATEST NAM SUGGESTS ANOTHER BATCH OF SHOWER ACTIVITY COULD BRUSH
NORTHERN COUNTIES VERY LATE MON NIGHT...ALTHOUGH THIS IS NOT WELL-
SUPPORTED BY OTHER SOLUTIONS. LASTLY...ALTHOUGH UNLIKELY...SUPPOSE
ITS NOT COMPLETELY OUT OF THE QUESTION THAT A LATE AFTERNOON
THUNDERSTORM COULD DEVELOP PRIMARILY IN THE SOUTHEAST CWA IN
RESPONSE TO 500-1000 J/KG OF 0-1KM MLCAPE...BUT FORECAST SOUNDINGS
SUGGEST THAT CAPPING AND LACK OF LIFT IN THE WAKE OF THE INITIAL
DEPARTING WAVE SHOULD PRECLUDE THIS SCENARIO. BOTTOM LINE...NO
PRECIP RISK MENTIONED AT THIS TIME. TEMP-WISE...ALTHOUGH STILL
QUITE WARM...SLIGHTLY LESS FAVORABLE MIXING THAN SUNDAY IS
EXPECTED TO KEEP TEMPS VERY SLIGHTLY COOLER...AND HAVE MOST AREAS
TOPPING OUT 77-82.
TUESDAY/TUESDAY NIGHT...AS MENTIONED ABOVE...THE LATE
AFTERNOON/EVENING TIME FRAME HOLDS THE BEST POTENTIAL FOR A ROUND
OF POTENTIALLY SEVERE STORMS MAINLY ACROSS THE SOUTHEAST 1/3 TO
1/2 OF THE CWA...BUT THIS IS ALSO FAR FROM A SURE THING AS SO MUCH
WILL DEPEND ON STILL-UNCERTAIN FRONTAL TIMING. ALOFT...BOTH THE
ECMWF/GFS SOLUTIONS ARE STILL IN PRETTY DECENT AGREEMENT AT THIS
POINT THAT A LARGE SCALE TROUGH AXIS WILL CONTINUE TO AMPLIFY
ALONG AN AXIS FROM THE NORTHERN PLAINS TO CENTRAL ROCKIES...WHILE
IN THE LOW LEVELS A RATHER HEALTHY COLD FRONT PUSHES SOUTHWARD
ACROSS THE CWA. ALTHOUGH A DECENT CAP SHOULD HOLD CONVECTION AT
BAY UNTIL AT LEAST MID-AFTERNOON...SOMETIME IN THE 21Z-01Z TIME
FRAME IS CURRENTLY EXPECTED TO FEATURE THE DEVELOPMENT OF STORMS
NEAR THE INVADING COLD FRONT...WHICH COULD BECOME SEVERE IN A
LIKELY QUASI-LINEAR FASHION PER THE ECMWF FORECAST OF 1000-1500
J/KG MLCAPE AND MODEST DEEP LAYER SHEAR. AS THE NIGHT WEARS
ON...THE OVERALL THUNDERSTORM INTENSITY SHOULD DIMINISH...BUT
COVERAGE OF WIDESPREAD RAIN AND EMBEDDED THUNDERSTORMS WOULD
INCREASE ACROSS NEARLY THE ENTIRE CWA AS A STRONGLY FORCED BAND OF
MID LEVEL CONVERGENCE/FRONTOGENESIS INVADES THE CWA FROM NORTHWEST
TO SOUTHEAST. ENOUGH CONSISTENCY IN THIS SCENARIO FOR TUESDAY
NIGHT EXISTS THAT POPS WERE RAISED INTO LIKELY TERRITORY IN MANY
AREAS. TEMP-WISE...HIGHS TUESDAY WILL BE TRICKY DUE TO UNCERTAINTY
IN THE SPEED OF THE INVADING COLD FRONT...BUT FOR NOW KEPT A
GENERAL RANGE FROM NEAR 70 NORTH TO NEAR 80 SOUTH.
FOR THE WEDNESDAY-FRIDAY TIME FRAME...THERE JUST ISN/T MUCH TO BE
GAINED YET BY GOING INTO MUCH DETAIL DUE TO VARYING MODEL
SOLUTIONS REGARDING THE EVOLUTION OF THE PASSING LARGE SCALE
TROUGH. IN GENERAL...BOTH THE 00Z ECMWF/GFS SOLUTIONS DEPICT A
SLOWING AND STALLING MID/UPPER TROUGH AS IT PASSES INTO THE
CENTRAL PORTION OF THE NATION...AS AN EXPANSIVE BLOCKING RIDGE
SETS UP SHOP OVER THE EASTERN CONUS. AS THIS BLOCK TAKES SHAPE...A
CLOSED...COLD AND FAIRLY COMPACT MID LEVEL LOW IS PROGGED TO FORM
SOMEWHERE...WITH THE ECMWF CLOSING THIS OFF OVER THE KS/OK AREA BY
THURS NIGHT INTO FRIDAY...WHILE THE GFS CLOSES THIS DEEP LOW OFF
MORE SO OVER MO/AR. ABOUT THE ONLY THING THE CURRENT FORECAST HAS
MUCH CONFIDENCE IN IS THAT DECENT PRECIP CHANCES WILL CONTINUE
ACROSS NEARLY THE ENTIRE CWA DURING THE DAY WEDNESDAY. HAVE KEPT
THIS RAIN FOR NOW...BUT THE VERY COLD ECMWF SOLUTION WOULD SUGGEST
A SNOW MIX POSSIBLE. THE CURRENT FORECAST THEN LINGERS A LESSER
CHANCE OF A RAIN/SNOW MIX ACROSS ROUGHLY THE SOUTHEAST 1/3 OF THE
CWA WED NIGHT...WHILE KEEPING THURSDAY-FRIDAY PRECIP-FREE.
HOWEVER...THIS PRECIP-FREE DEPICTION WILL NOT LAST IF THE ECMWF IS
IN FACT ONTO SOMETHING...AS IT DEPICTS A POSSIBLE RAIN/SNOW MIX
LASTING INTO FRIDAY IN SOME AREAS. RE-EMPHASIZING THE MAIN POINTS
HERE...A MUCH COOLER WEATHER REGIME WILL SETTLE IN BY MID-LATE
WEEK...BUT WE ARE STILL A FEW DAYS AWAY FROM PINNING DOWN JUST
HOW COLD IT MIGHT REALLY GET...AND WHETHER A RISK REALLY EXISTS
FOR POSSIBLY ANOTHER ROUND OF LATE-SEASON SNOW AND/OR SUB-
FREEZING OVERNIGHT LOW TEMPS. STAY TUNED...
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1252 AM CDT SAT APR 27 2013
THE BIGGEST ISSUE WILL BE VISIBILITY. THE HRRR MODEL SEEMS TO BE
DOING THE BEST AT PICKING UP ON FOG AND STRATUS TO THE SOUTH...SO
FOLLOWING THIS MODEL MORE CLOSELY THAN THE OTHERS...WHICH ARE NOT
PREDICTING MUCH FOG IF ANY. SUBSIDENCE SHOULD HELP SCOUR OUT THE
FOG AND STRATUS BY MID-MORNING SATURDAY.
&&
.FIRE WEATHER...
ISSUED AT 535 AM CDT SAT APR 27 2013
BOTH TODAY AND SUNDAY...THE LATEST FORECASTS NOW PUSH AFTERNOON
RELATIVE HUMIDITY VALUES BELOW 20 PERCENT IN PARTS OF THE CWA.
HOWEVER...THE PRESENCE OF LIGHTER WINDS THAN THOSE OBSERVED FRIDAY
IS CURRENTLY EXPECTED TO KEEP OVERALL FIRE DANGER RATHER
LIMITED...AS OPPOSED TO ELEVATED TO CRITICAL AS MIGHT BE THE CASE
WITH STRONGER WINDS. FOCUSING FIRST ON TODAY...SUB-20 PERCENT
RELATIVE HUMIDITY IS FORECAST TO FOCUS ONLY IN FAR
WESTERN/NORTHERN AREAS...GENERALLY WEST OF A GREELEY-BEAVER CITY
LINE. THEN ON SUNDAY...SUB-20 PERCENT RH IS PROGGED TO DEVELOP
ACROSS MOST COUNTIES WEST OF THE HIGHWAY 281 CORRIDOR. OF THE TWO
AFTERNOONS...SUNDAY BEARS THE MOST WATCHING TO MAKE SURE WINDS
SPEEDS DON/T CREEP HIGHER THAN CURRENTLY FORECAST.
FOR NOW...SUSTAINED WESTERLY SPEEDS AT MOST 10-15 MPH/GUSTS AT
MOST 15-20 MPH ARE FORECAST...KEEPING THINGS 5-10 MPH SHORT OF
POTENTIALLY CRITICAL FIRE THRESHOLDS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ040-041-
046>049-060>064-072>077-082>087.
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ005>007-
017-018.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
FIRE WEATHER...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
348 AM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT SAT APR 27 2013
LOW PRESSURE WILL CONTINUE TO TRACK ACROSS SRN CANADA TODAY
PRODUCING SOUTHWEST WINDS AHEAD OF A NORTHWEST WIND SHIFT ACROSS
NORTHWEST NEBRASKA. LIGHT WINDS...DEEP VERTICAL MIXING...NEARLY FULL
SUN AND A STRONG THERMAL RIDGE SHOULD PRODUCE HIGHS AROUND 80. THE
RAP MODEL IS LEADING THE WAY WITH THIS FEATURE.
TONIGHT...WEST WINDS DEVELOP MAINTAINING A THERMAL RIDGE ACROSS THE
FORECAST AREA AND LOWS IN THE 30S TO NEAR 40.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 348 AM CDT SAT APR 27 2013
ANOTHER DAY OF WELL ABOVE
NORMAL TEMPERATURES WILL BE EXPECTED FOR SUNDAY AS GUIDANCE SUGGEST
H85 TEMPERATURES APPROACHING...IF NOT EXCEEDING 20C. THE WARM LOWER
LEVELS WILL ALLOW SURFACE TEMPERATURES TO CLIMB WELL INTO THE
70S...AND POSSIBLY LOW 80S ACROSS THE ENTIRE FORECAST AREA. WITH THE
WELL ABOVE CLIMO HIGHS EXPECTED...FIRE CONCERNS WILL ONCE AGAIN
FLIRT WITH CRITICAL THRESHOLDS BY EARLY AFTERNOON. THE LOWEST RH
READINGS ARE ANTICIPATED ACROSS OUR WESTERN AND SOUTHERN FIRE ZONES
WHERE A EASTWARD ADVANCING SURFACE TROUGH LOW PRESSURE WILL WORK IN
CONCERT WITH STRONG TROPOSPHERIC MIXING TO ALLOW FOR OCCASIONAL
WIND GUSTS AT OR NEAR 20KTS /SLIGHTLY BELOW RFW WIND THRESHOLD/.
WILL HOLD OFF ON ANY FIRE HEADLINE FOR NOW. INTO THE OVERNIGHT A
WEAK PERTURBATION WILL RAPIDLY ADVANCE THROUGH QUASI-ZONAL FLOW AND
BRING A CHANCE OF A SHOWER...OR POSSIBLY A THUNDERSTORM...TO
NORTHERN PORTIONS OF THE CWA. THE OPERATIONAL MODELS INDICATE
ENOUGH OMEGA FOR PRECIPITATION PRODUCTION FOR MUCH OF THE
CWA...HOWEVER BUFR PROXIMITY SOUNDINGS SUGGEST THE LOWER TROPOSPHERE
WILL REMAIN FAIRLY DRY...THUS WILL MAINTAIN SLIGHT TO LOW END CHANCE
POPS ACROSS OUR NORTH OVERNIGHT SUNDAY INTO MONDAY...GENERALLY TIED
TO THE STRONGEST OMEGA AND BEST LOWER LEVEL MOISTURE PROFILES...BUT
LEAVE THE SOUTHERN HALF OF THE CWA MAINLY DRY...WITH ONLY A MENTION
OF SPRINKLES. SIMILAR CONDITIONS ARE EXPECTED FOR MONDAY...WITH THE
POSSIBILITY OF SLIGHTLY WARMER TEMPERATURES AND GREATER GUSTS. RED
FLAG WARNINGS MAY BE NEEDED FOR THE AFTERNOON HOURS. DRY CONDITIONS
WILL PREVAIL INTO EARLY TUESDAY AS A LACK IN KINEMATIC FORCING
RETURNS ONCE AGAIN...HOWEVER PRECIPITATION CHANCES INCREASE DURING
THE AFTERNOON HOURS ON TUESDAY AS A BAROCLINIC ZONE AND ASSOCIATED
SHORTWAVE CROSSES THE REGION. BESIDES THE PRECIPITATION
CHANCES...TEMPERATURES WILL BE MARKEDLY COOLER FOR MIDWEEK BEHIND
THE PASSING FRONT. IN FACT...FREEZE CONCERNS MAY BE REALIZED EARLY
WEDNESDAY AS THE LONGER RANGE SOLUTIONS SUGGEST H85 TEMPERATURES
FALL SOME 20-25C...WHICH WOULD PROVIDE FOR LOWS IN THE UPPER
20S-LOWER 30S AND HIGHS MAINLY IN THE 50S THROUGH MIDWEEK. THE
LONGER RANGE SOLUTION REMAIN IN POOR AGREEMENT AND THUS CONFIDENCE
IS LOW FOR MIDWEEK AND BEYOND...BUT THE GENERAL IDEA REMAINS OF
BROAD CYCLONIC FLOW ACROSS THE CENTRAL CONUS THROUGH THE END OF THE
WORK WEEK...WITH SLOWLY MODERATING TEMPERATURES AND POSSIBLY A
CHANCE AT ADDITIONAL PRECIPITATION. BUT WITH THE LOW CONFIDENCE IN
THE EXTENDED FORECAST...WILL MAINTAIN A DRY FORECAST BEYOND
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1229 AM CDT SAT APR 27 2013
A WEAK SURFACE FRONT...MOSTLY A DEWPOINT CONTRAST...WILL BE THE
BOUNDARY OF SOME STRATUS AND/OR FOG IN PART OF CENTRAL AND SOUTH
CENTRAL NEBRASKA. AT THIS TIME...WE DO NOT EXPECT THOSE CONDITIONS
TO REACH BBW OR LBF. OTHERWISE...CEILINGS AND VISIBILITY WILL BE
UNRESTRICTED THROUGH TONIGHT AND INTO SATURDAY EVENING. WIND IS
EXPECTED TO SWING AROUND TO THE WEST AND SOUTHWEST MOST AREAS BUT
ARE STILL EXPECTED TO BE 12KT OR LOWER.
&&
.FIRE WEATHER...
ISSUED AT 348 AM CDT SAT APR 27 2013
A 75 PERCENT BLEND OF THE RAP AND 25 PERCENT OF THE REST OF THE
MODELS PRODUCES RELATIVE HUMIDITY BETWEEN 10 AND 20 PERCENT ACROSS
THE FCST AREA. ALL INDICATIONS ARE WINDS WILL BE WEAK AT LESS THAN
20 MPH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
310 AM CDT SAT APR 27 2013
.UPDATE...
ISSUED AT 305 AM CDT SAT APR 27 2013
WITH MORE OBSERVATIONS QUICKLY TANKING TO 1/4 VISIBILITY...I
DECIDED TO GO COMPLETELY WITH THE HRRR SOLUTION AND INCLUDE ALL
BUT VALLEY COUNTY IN THE NORTH AND MITCHELL COUNTY IN THE SOUTH IN
THE DENSE FOG ADVISORY. WE SEEM TO BE IN THE MIDST OF A
CONVERGENCE AREA THAT IS PROMOTING FOG AND STRATUS DEVELOPMENT.
UPDATE ISSUED AT 1252 AM CDT SAT APR 27 2013
HIT THE FOG A LITTLE HARDER IN THIS UPDATE AS THE HRRR SEEMS TO BE
PICKING UP THE FOG TO THE SOUTH THE BEST. IF WE CONTINUE TO
TANK...WE COULD END UP WITH A DENSE FOG ADVISORY FOR A GOOD CHUNK
OF THE CWA THIS MORNING.
UPDATE ISSUED AT 902 PM CDT FRI APR 26 2013
WITH TEMPERATURES APPROACHING THE DEW POINTS ACROSS NORTH CENTRAL
KANSAS ALREADY THIS EVENING AND LIGHT SOUTHEASTERLY WINDS
ADVECTING ADDITIONAL MOISTURE NORTHWARD...DECIDED TO INSERT SOME
AREAS OF FOG INTO THE FORECAST DURING THE OVERNIGHT/EARLY MORNING
HOURS TOMORROW. 00Z HRRR IS VERY AGGRESSIVE WITH WIDESPREAD
VISIBILITIES DROPPING TO 1/4 SM...BUT SREF PROBS KEEP LOWER
VISIBILITIES SOUTH OF THE LOCAL AREA...SO WENT AHEAD WITH A
COMPROMISE...BRINGING FOG UP TO AROUND HIGHWAY 6 IN SOUTH CENTRAL
NEBRASKA OVERNIGHT. OTHERWISE...NO ADDITIONAL CHANGES MADE TO
PREVIOUS FORECAST AT THIS TIME.
UPDATE ISSUED AT 650 PM CDT FRI APR 26 2013
WENT AHEAD AND UPDATED THE FORECAST TO REMOVE THE SMALL CHANCES
FOR THUNDERSTORMS THIS EVENING AS WHILE THE SPC MESO ANALYSIS PAGE
INDICATES THERE ARE A COUPLE HUNDRED JOULES OF CAPE ACROSS OUR AREA
RIGHT NOW...THIS WILL DIMINISH OVER THE NEXT COUPLE OF HOURS AND
THUS FAR SHOWERS AND THUNDERSTORMS HAVE LACKED A TRIGGER FOR
DEVELOPMENT. OTHER THAN REMOVING THESE SMALL CHANCES FOR
PRECIPITATION...NO ADDITIONAL CHANGES WERE MADE TO THE PREVIOUS
FORECAST AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CDT FRI APR 26 2013
MAIN FOCUS IN THE SHORT TERM WILL CENTER AROUND SLIGHT CHANCES FOR
THUNDERSTORMS AND HIGH TEMPERATURES SATURDAY.
A QUICK SYNOPTIC ANALYSIS REVEALS MOSTLY ZONAL FLOW ACROSS THE
CONUS WITH THE EXCEPTION OF AN OPEN WAVE TROUGH ACROSS THE
ROCKIES. AT THE SURFACE...HIGH PRESSURE REMAINED SITUATED ACROSS
BOTH COASTS WITH A WEAK LOW PRESSURE SYSTEM ACROSS THE TEXAS
PANHANDLE. THE OPEN WAVE BEGAN TO SHIFT JUST SOUTH OF THE PLAINS
THIS MORNING...WHICH BROUGHT SHOWERS AND THUNDERSTORMS TO PORTIONS
OF KANSAS. SATELLITE IMAGERY REVEALS A THICK CLOUD COVER OVER MUCH
OF SOUTHEAST KANSAS AND MISSOURI WITH THINNING CIRRUS DECK ACROSS
SOUTHERN NEBRASKA AND IOWA. A SURFACE TROUGH ASSOCIATED WITH THE
LOW IN THE PANHANDLE ALSO BEGAN SHIFTING ACROSS THE PLAINS THIS
AFTERNOON AS WELL. A STRONG 850 MB JET STREAK ON THE BACKSIDE OF
THIS TROUGH ALSO SHIFTED ACROSS NEBRASKA THIS AFTERNOON. COMBINED
WITH STRONG MIXING...THIS JET STREAK LED TO A BRIEF PERIOD OF
STRONGER WIND GUSTS NEAR 30 MPH AND LOW RH VALUES NEAR 20 PERCENT.
THESE CONDITIONS WERE SEEN OVER A FAIRLY SMALL LOCALIZED AREA
STRETCHING FROM MCCOOK TO ORD WESTWARD.
FOR THE REST OF THE AFTERNOON...SHORT TERM MODELS INDICATE THE
WEAKENING OF THE 850 JET STREAK WHICH SHOULD RELAX WINDS AND HELP
STEADY RH VALUES. CURRENT THINKING IS WINDS WILL REMAIN MARGINAL
AROUND 20 TO 25 MPH FOR THE NEXT FEW HOURS OR SO ESPECIALLY WEST
OF A LINE FROM MCCOOK TO KEARNEY TO ORD BEFORE DECREASING BY LATE
THIS AFTERNOON AND EARLY EVENING.
AS THE SURFACE TROUGH CONTINUES TO SHIFT EASTWARD...MODELS ALSO
HINT AT THE POSSIBILITY FOR SOME ADDITIONAL SHOWER DEVELOPMENT
NEAR THE BOUNDARY...MAINLY SOUTH OF LINE FROM CAMBRIDGE TO
FULLERTON. WITH INSTABILITY PARAMETERS NEAR 300 TO 500 J/KG KEPT
MENTION OF THUNDER IN THE FORECAST FROM 0Z TO 3Z WITH DIMINISHING
INSTABILITY THEREAFTER LIKELY DECREASING THUNDER THREAT. AT THIS
POINT...REALLY THINKING ISOLATED LIGHT SHOWERS WITH MAYBE A RUMBLE
OF THUNDER OR TWO. HRRR AND 4 KM WRF MODEL ALSO IN AGREEMENT WITH
THIS THINKING.
HEADING INTO SATURDAY...THE UPPER LEVEL RIDGE SLOWLY BEGINS TO
BUILD EASTWARD INTO THE PLAINS BEHIND THE TROUGH AXIS. WARMER 850
MB TEMPERATURES WILL ALSO SLIDE INTO THE REGION. SHOULD BE A
FAIRLY NICE AND BRIGHT DAY WITH SURFACE HIGH PRESSURE OVER THE
FORECAST AREA...LIGHT NORTH WINDS AND TEMPERATURES RANGING IN THE
70S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CDT FRI APR 26 2013
GUIDANCE SUGGESTS AN OVERALL LACK IN KINEMATIC FORCING SHOULD
PROVIDE DRY CONDITIONS TO OUR AREA SUNDAY INTO SUNDAY EVENING.
DURING THE EARLY MORNING HOURS ON MONDAY HOWEVER...THERE ARE
INDICATIONS OF A WEAK MID LEVEL PERTURBATION MOVING OVER THE
REGION WITH PERHAPS ENOUGH OMEGA FOR PRECIPITATION PRODUCTION.
THAT BEING SAID FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR
AREA...PER THE NAM AND OPERATIONAL GFS...SUGGEST THE LOWER
TROPOSPHERE WILL REMAIN FAIRLY DRY AND AS A RESULT...IT IS
CURRENTLY BELIEVED NOTHING MORE THAN A FEW SPRINKLES WILL BE
REALIZED ACROSS THE AREA EARLY MONDAY MORNING. GIVEN ALL
THIS...WENT AHEAD WITH A SPRINKLE MENTION IN THE
FORECAST...PRIMARILY FOR LOCATIONS ACROSS OUR NORTH/NORTHWEST
WHERE OMEGA IS EXPECTED TO BE STRONGEST. DRY CONDITIONS ARE THEN
FORECAST INTO THE DAY MONDAY AND MONDAY NIGHT AS A LACK IN
KINEMATIC FORCING OVERTAKES THE AREA ONCE AGAIN.
ANOTHER CHANCE AT PRECIPITATION IS THEN FORECAST TUESDAY THROUGH
WEDNESDAY NIGHT AS A MID LEVEL SHORT WAVE IS EXPECTED TO MOVE OVER
PORTIONS OF THE NORTHERN AND CENTRAL PLAINS. AN ASSOCIATED SURFACE
LOW IS ALSO EXPECTED TO MOVE ACROSS PORTIONS OF THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY WITH A LOW LEVEL BAROCLINIC
ZONE FORECAST TO MOVE ACROSS OUR CWA AT SOME POINT DURING THE DAY
TUESDAY. TIMING THE PASSAGE OF THE LOW LEVEL BAROCLINIC ZONE IS
DIFFICULT GIVEN THIS SYSTEM IS STILL 4 DAYS OUT...BUT AT THIS TIME
IT APPEARS LOCATIONS AHEAD OF THE BAROCLINIC ZONE WILL OBSERVE A
SURFACE DEWPOINT IN THE MID TO UPPER 50S. THIS LOW LEVEL
MOISTURE...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE
RATES WITH THE APPROACH OF THE MID LEVEL SHORT WAVE...COULD
POTENTIALLY PROMOTE 0-1KM MLCAPE VALUES ANYWHERE BETWEEN 500J/KG
AND 1500J/KG. INCREASING MID TO UPPER LEVEL FLOW IS ALSO EXPECTED
TO INCREASE DEEP LAYER BULK SHEAR TO BETWEEN 30KTS AND 40KTS.
GIVEN ALL THIS...IT CERTAINLY APPEARS SEVERE WEATHER COULD BE
REALIZED AT LOCATIONS STILL OUT AHEAD OF THE LOW LEVEL BAROCLINIC
ZONE TUESDAY AFTERNOON AND EVENING. AT THIS TIME IT ALSO APPEARS
THE SOUTHEASTERN ONE-THIRD OF OUR CWA STANDS THE BEST CHANCE AT
OBSERVING SEVERE WEATHER AND AS A RESULT...WILL CONTINUE SUCH
WORDING IN THE HWO.
ANY SEVERE WEATHER THAT IS REALIZED ACROSS THE AREA TUESDAY
AFTERNOON AND EVENING SHOULD QUICKLY DEPART TO THE EAST/SOUTHEAST
TUESDAY NIGHT AS THE LOW LEVEL BAROCLINIC ZONE DOES THE SAME.
DECREASING LOW LEVEL MOISTURE SHOULD ALLOW FOR DECREASING
POTENTIAL INSTABILITY BUT WITH INCREASING OMEGA DUE TO THE
APPROACHING MID LEVEL SHORT WAVE...CHANCES FOR PRECIPITATION
CONTINUE IN THE FORECAST FOR MOST ALL OF OUR CWA TUESDAY NIGHT
INTO WEDNESDAY...AND LINGERING ACROSS OUR EAST/SOUTHEAST WEDNESDAY
NIGHT. DRY CONDITIONS ARE THEN FORECAST THURSDAY ONWARD.
A VERY WARM LOW LEVEL AIRMASS WILL CONTINUE TO PROMOTE AN
AFTERNOON HIGH TEMPERATURE IN THE 70S TO LOW 80S SUNDAY THROUGH
TUESDAY. THE PASSAGE OF THE LOW LEVEL BAROCLINIC ZONE ON TUESDAY
HOWEVER WILL THEN BRING AN END TO THE WARM WEATHER...WITH A COOLER
LOW LEVEL AIRMASS LIKELY PROMOTING AN AFTERNOON HIGH TEMPERATURE
IN THE 50S AND 60S TO FINISH OUT THE FORECAST PERIOD. AN OVERNIGHT
LOW TEMPERATURE IN THE 40S AND 50S IS EXPECTED SUNDAY NIGHT
THROUGH TUESDAY NIGHT...WITH LOWS RANGING FROM THE MID 30S TO THE
LOW 40S WEDNESDAY NIGHT ONWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1252 AM CDT SAT APR 27 2013
THE BIGGEST ISSUE WILL BE VISIBILITY. THE HRRR MODEL SEEMS TO BE
DOING THE BEST AT PICKING UP ON FOG AND STRATUS TO THE SOUTH...SO
FOLLOWING THIS MODEL MORE CLOSELY THAN THE OTHERS...WHICH ARE NOT
PREDICTING MUCH FOG IF ANY. SUBSIDENCE SHOULD HELP SCOUR OUT THE
FOG AND STRATUS BY MID-MORNING SATURDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ040-041-
046>049-060>064-072>077-082>087.
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ005>007-
017-018.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...SALTZMAN
LONG TERM...BRYANT
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
100 AM CDT SAT APR 27 2013
.UPDATE...
ISSUED AT 1252 AM CDT SAT APR 27 2013
HIT THE FOG A LITTLE HARDER IN THIS UPDATE AS THE HRRR SEEMS TO BE
PICKING UP THE FOG TO THE SOUTH THE BEST. IF WE CONTINUE TO
TANK...WE COULD END UP WITH A DENSE FOG ADVISORY FOR A GOOD CHUNK
OF THE CWA THIS MORNING.
UPDATE ISSUED AT 902 PM CDT FRI APR 26 2013
WITH TEMPERATURES APPROACHING THE DEW POINTS ACROSS NORTH CENTRAL
KANSAS ALREADY THIS EVENING AND LIGHT SOUTHEASTERLY WINDS
ADVECTING ADDITIONAL MOISTURE NORTHWARD...DECIDED TO INSERT SOME
AREAS OF FOG INTO THE FORECAST DURING THE OVERNIGHT/EARLY MORNING
HOURS TOMORROW. 00Z HRRR IS VERY AGGRESSIVE WITH WIDESPREAD
VISIBILITIES DROPPING TO 1/4 SM...BUT SREF PROBS KEEP LOWER
VISIBILITIES SOUTH OF THE LOCAL AREA...SO WENT AHEAD WITH A
COMPROMISE...BRINGING FOG UP TO AROUND HIGHWAY 6 IN SOUTH CENTRAL
NEBRASKA OVERNIGHT. OTHERWISE...NO ADDITIONAL CHANGES MADE TO
PREVIOUS FORECAST AT THIS TIME.
UPDATE ISSUED AT 650 PM CDT FRI APR 26 2013
WENT AHEAD AND UPDATED THE FORECAST TO REMOVE THE SMALL CHANCES
FOR THUNDERSTORMS THIS EVENING AS WHILE THE SPC MESO ANALYSIS PAGE
INDICATES THERE ARE A COUPLE HUNDRED JOULES OF CAPE ACROSS OUR AREA
RIGHT NOW...THIS WILL DIMINISH OVER THE NEXT COUPLE OF HOURS AND
THUS FAR SHOWERS AND THUNDERSTORMS HAVE LACKED A TRIGGER FOR
DEVELOPMENT. OTHER THAN REMOVING THESE SMALL CHANCES FOR
PRECIPITATION...NO ADDITIONAL CHANGES WERE MADE TO THE PREVIOUS
FORECAST AT THIS TIME.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 320 PM CDT FRI APR 26 2013
MAIN FOCUS IN THE SHORT TERM WILL CENTER AROUND SLIGHT CHANCES FOR
THUNDERSTORMS AND HIGH TEMPERATURES SATURDAY.
A QUICK SYNOPTIC ANALYSIS REVEALS MOSTLY ZONAL FLOW ACROSS THE
CONUS WITH THE EXCEPTION OF AN OPEN WAVE TROUGH ACROSS THE
ROCKIES. AT THE SURFACE...HIGH PRESSURE REMAINED SITUATED ACROSS
BOTH COASTS WITH A WEAK LOW PRESSURE SYSTEM ACROSS THE TEXAS
PANHANDLE. THE OPEN WAVE BEGAN TO SHIFT JUST SOUTH OF THE PLAINS
THIS MORNING...WHICH BROUGHT SHOWERS AND THUNDERSTORMS TO PORTIONS
OF KANSAS. SATELLITE IMAGERY REVEALS A THICK CLOUD COVER OVER MUCH
OF SOUTHEAST KANSAS AND MISSOURI WITH THINNING CIRRUS DECK ACROSS
SOUTHERN NEBRASKA AND IOWA. A SURFACE TROUGH ASSOCIATED WITH THE
LOW IN THE PANHANDLE ALSO BEGAN SHIFTING ACROSS THE PLAINS THIS
AFTERNOON AS WELL. A STRONG 850 MB JET STREAK ON THE BACKSIDE OF
THIS TROUGH ALSO SHIFTED ACROSS NEBRASKA THIS AFTERNOON. COMBINED
WITH STRONG MIXING...THIS JET STREAK LED TO A BRIEF PERIOD OF
STRONGER WIND GUSTS NEAR 30 MPH AND LOW RH VALUES NEAR 20 PERCENT.
THESE CONDITIONS WERE SEEN OVER A FAIRLY SMALL LOCALIZED AREA
STRETCHING FROM MCCOOK TO ORD WESTWARD.
FOR THE REST OF THE AFTERNOON...SHORT TERM MODELS INDICATE THE
WEAKENING OF THE 850 JET STREAK WHICH SHOULD RELAX WINDS AND HELP
STEADY RH VALUES. CURRENT THINKING IS WINDS WILL REMAIN MARGINAL
AROUND 20 TO 25 MPH FOR THE NEXT FEW HOURS OR SO ESPECIALLY WEST
OF A LINE FROM MCCOOK TO KEARNEY TO ORD BEFORE DECREASING BY LATE
THIS AFTERNOON AND EARLY EVENING.
AS THE SURFACE TROUGH CONTINUES TO SHIFT EASTWARD...MODELS ALSO
HINT AT THE POSSIBILITY FOR SOME ADDITIONAL SHOWER DEVELOPMENT
NEAR THE BOUNDARY...MAINLY SOUTH OF LINE FROM CAMBRIDGE TO
FULLERTON. WITH INSTABILITY PARAMETERS NEAR 300 TO 500 J/KG KEPT
MENTION OF THUNDER IN THE FORECAST FROM 0Z TO 3Z WITH DIMINISHING
INSTABILITY THEREAFTER LIKELY DECREASING THUNDER THREAT. AT THIS
POINT...REALLY THINKING ISOLATED LIGHT SHOWERS WITH MAYBE A RUMBLE
OF THUNDER OR TWO. HRRR AND 4 KM WRF MODEL ALSO IN AGREEMENT WITH
THIS THINKING.
HEADING INTO SATURDAY...THE UPPER LEVEL RIDGE SLOWLY BEGINS TO
BUILD EASTWARD INTO THE PLAINS BEHIND THE TROUGH AXIS. WARMER 850
MB TEMPERATURES WILL ALSO SLIDE INTO THE REGION. SHOULD BE A
FAIRLY NICE AND BRIGHT DAY WITH SURFACE HIGH PRESSURE OVER THE
FORECAST AREA...LIGHT NORTH WINDS AND TEMPERATURES RANGING IN THE
70S.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 320 PM CDT FRI APR 26 2013
GUIDANCE SUGGESTS AN OVERALL LACK IN KINEMATIC FORCING SHOULD
PROVIDE DRY CONDITIONS TO OUR AREA SUNDAY INTO SUNDAY EVENING.
DURING THE EARLY MORNING HOURS ON MONDAY HOWEVER...THERE ARE
INDICATIONS OF A WEAK MID LEVEL PERTURBATION MOVING OVER THE
REGION WITH PERHAPS ENOUGH OMEGA FOR PRECIPITATION PRODUCTION.
THAT BEING SAID FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR
AREA...PER THE NAM AND OPERATIONAL GFS...SUGGEST THE LOWER
TROPOSPHERE WILL REMAIN FAIRLY DRY AND AS A RESULT...IT IS
CURRENTLY BELIEVED NOTHING MORE THAN A FEW SPRINKLES WILL BE
REALIZED ACROSS THE AREA EARLY MONDAY MORNING. GIVEN ALL
THIS...WENT AHEAD WITH A SPRINKLE MENTION IN THE
FORECAST...PRIMARILY FOR LOCATIONS ACROSS OUR NORTH/NORTHWEST
WHERE OMEGA IS EXPECTED TO BE STRONGEST. DRY CONDITIONS ARE THEN
FORECAST INTO THE DAY MONDAY AND MONDAY NIGHT AS A LACK IN
KINEMATIC FORCING OVERTAKES THE AREA ONCE AGAIN.
ANOTHER CHANCE AT PRECIPITATION IS THEN FORECAST TUESDAY THROUGH
WEDNESDAY NIGHT AS A MID LEVEL SHORT WAVE IS EXPECTED TO MOVE OVER
PORTIONS OF THE NORTHERN AND CENTRAL PLAINS. AN ASSOCIATED SURFACE
LOW IS ALSO EXPECTED TO MOVE ACROSS PORTIONS OF THE NORTHERN
PLAINS AND UPPER MISSISSIPPI VALLEY WITH A LOW LEVEL BAROCLINIC
ZONE FORECAST TO MOVE ACROSS OUR CWA AT SOME POINT DURING THE DAY
TUESDAY. TIMING THE PASSAGE OF THE LOW LEVEL BAROCLINIC ZONE IS
DIFFICULT GIVEN THIS SYSTEM IS STILL 4 DAYS OUT...BUT AT THIS TIME
IT APPEARS LOCATIONS AHEAD OF THE BAROCLINIC ZONE WILL OBSERVE A
SURFACE DEWPOINT IN THE MID TO UPPER 50S. THIS LOW LEVEL
MOISTURE...WORKING IN CONCERT WITH INCREASING MID LEVEL LAPSE
RATES WITH THE APPROACH OF THE MID LEVEL SHORT WAVE...COULD
POTENTIALLY PROMOTE 0-1KM MLCAPE VALUES ANYWHERE BETWEEN 500J/KG
AND 1500J/KG. INCREASING MID TO UPPER LEVEL FLOW IS ALSO EXPECTED
TO INCREASE DEEP LAYER BULK SHEAR TO BETWEEN 30KTS AND 40KTS.
GIVEN ALL THIS...IT CERTAINLY APPEARS SEVERE WEATHER COULD BE
REALIZED AT LOCATIONS STILL OUT AHEAD OF THE LOW LEVEL BAROCLINIC
ZONE TUESDAY AFTERNOON AND EVENING. AT THIS TIME IT ALSO APPEARS
THE SOUTHEASTERN ONE-THIRD OF OUR CWA STANDS THE BEST CHANCE AT
OBSERVING SEVERE WEATHER AND AS A RESULT...WILL CONTINUE SUCH
WORDING IN THE HWO.
ANY SEVERE WEATHER THAT IS REALIZED ACROSS THE AREA TUESDAY
AFTERNOON AND EVENING SHOULD QUICKLY DEPART TO THE EAST/SOUTHEAST
TUESDAY NIGHT AS THE LOW LEVEL BAROCLINIC ZONE DOES THE SAME.
DECREASING LOW LEVEL MOISTURE SHOULD ALLOW FOR DECREASING
POTENTIAL INSTABILITY BUT WITH INCREASING OMEGA DUE TO THE
APPROACHING MID LEVEL SHORT WAVE...CHANCES FOR PRECIPITATION
CONTINUE IN THE FORECAST FOR MOST ALL OF OUR CWA TUESDAY NIGHT
INTO WEDNESDAY...AND LINGERING ACROSS OUR EAST/SOUTHEAST WEDNESDAY
NIGHT. DRY CONDITIONS ARE THEN FORECAST THURSDAY ONWARD.
A VERY WARM LOW LEVEL AIRMASS WILL CONTINUE TO PROMOTE AN
AFTERNOON HIGH TEMPERATURE IN THE 70S TO LOW 80S SUNDAY THROUGH
TUESDAY. THE PASSAGE OF THE LOW LEVEL BAROCLINIC ZONE ON TUESDAY
HOWEVER WILL THEN BRING AN END TO THE WARM WEATHER...WITH A COOLER
LOW LEVEL AIRMASS LIKELY PROMOTING AN AFTERNOON HIGH TEMPERATURE
IN THE 50S AND 60S TO FINISH OUT THE FORECAST PERIOD. AN OVERNIGHT
LOW TEMPERATURE IN THE 40S AND 50S IS EXPECTED SUNDAY NIGHT
THROUGH TUESDAY NIGHT...WITH LOWS RANGING FROM THE MID 30S TO THE
LOW 40S WEDNESDAY NIGHT ONWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1252 AM CDT SAT APR 27 2013
THE BIGGEST ISSUE WILL BE VISIBILITY. THE HRRR MODEL SEEMS TO BE
DOING THE BEST AT PICKING UP ON FOG AND STRATUS TO THE SOUTH...SO
FOLLOWING THIS MODEL MORE CLOSELY THAN THE OTHERS...WHICH ARE NOT
PREDICTING MUCH FOG IF ANY. SUBSIDENCE SHOULD HELP SCOUR OUT THE
FOG AND STRATUS BY MID-MORNING SATURDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...SALTZMAN
LONG TERM...BRYANT
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1147 PM CDT FRI APR 26 2013
.DISCUSSION...
PULLED ALL MENTION OF RAIN FROM THE SOUTHEASTERN FORECAST AREA
TONIGHT AND ON SATURDAY. ALSO ADDED IN SOME PATCHY FOG LATE
TONIGHT AND SATURDAY MORNING ALONG AND SOUTH OF THE STALLED
SURFACE TROUGH THAT EXISTS FROM COLUMBUS TO TEKAMAH WHERE
DEWPOINTS ARE IN THE MID TO UPPER 40S. RUC WAS INDICATING SOME
PROBABILITY FOR DENSE FOG ACROSS SOUTH CENTRAL INTO SOUTHEAST
NEBRASKA...AS WAS THE MOST RECENT MET GUIDANCE. THIS WOULD LIKELY
DEVELOP ON THE NORTHERN FRINGE OF SOME STRATUS THAT REMAINED ALONG
THE NE/SD BORDER REGION. THE STRATUS WAS ALSO SLOWLY MOVING
NORTHWARD ALONG THE MISSOURI RIVER AND INTO SOUTHWEST IOWA.
DEWALD
&&
.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS AT
KOFK WITH LIGHT AND VARIABLE WINDS THROUGH THE PERIOD. FORECAST A
PERIOD OF MVFR CONDITIONS AT KLNK/KOMA FROM 09Z-14Z AS PATCHY FOG
MIGHT DEVELOP. FOG COULD BRIEFLY GO DOWN TO IFR LEVELS AT KLNK
BASED ON MODEL TRENDS. MVFR STRATUS DECK MAY ALSO MOVE INTO KOMA
DURING THAT SAME TIME AS WELL. OTHERWISE...SOUTH TO SOUTHEAST
WINDS LESS THAN 10KTS THROUGH THE PERIOD.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 335 PM CDT FRI APR 26 2013/
SHORT TERM...TONIGHT THROUGH MONDAY.
THERE ARE SEVERAL ISSUES IN THIS TIME PERIOD. THE MAIN ONES ARE THE
CHANCE FOR SHOWERS/ISOLATED THUNDERSTORMS THIS EVENING...THE CHANCE
OF PCPN WITH THE FRONT FROM LATE SUNDAY INTO MONDAY AND TEMPERATURES
THE NEXT FEW DAYS.
TONIGHT...A WEAK FRONTAL BOUNDARY EXTENDING FROM NORTHEAST TO
SOUTHWEST ACROSS THE AREA MAY BE ENOUGH TO HELP TRIGGER SOME VERY
LIGHT SHOWERS OR SPRINKLES THIS EVENING. SOME OF THE MODELS HAVE
BEEN SHOWING THAT...INCLUDING RECENT RUNS OF RAPID REFRESH...
ALTHOUGH THE MOST RECENT RUNS ARE NOT AS BULLISH WITH FORECAST
REFLECTIVITY VALUES AS COMPARED TO THE EARLIER RUNS. THIS IS IN
AREA WHICH APPEARS TO HAVE SLIGHTLY HIGHER 850 MB MOISTURE. THERE
IS ALSO SOME SMALL ELEVATED CAPE...BUT DID NOT MENTION THUNDER AT
THIS POINT. LARGER SCALE FORCING WITH SYSTEM TO THE SOUTH WILL
PRODUCE PCPN ACROSS KANSAS AND MISSOURI...AND POSSIBLY INTO THE
FAR SOUTHWEST CORNER OF IOWA AND SOUTHEAST NEBRASKA. KEPT SOME
POPS IN PLACE FOR THAT. LOWS SHOULD HOLD IN THE LOWER TO MID 40S
SOUTH BUT MAY DROP INTO THE 30S NORTH WHERE CLOUD COVER WILL BE
LESS.
ON SATURDAY...WINDS REMAIN FAIRLY LIGHT AND MIXING WILL BE POOR. THE
RESULT SHOULD BE HIGHS CLOSE TO MOS GUIDANCE...IN THE UPPER 60S OR
LOWER 70S. AGAIN...SOME OF THE MODELS HINT AT SOME LIGHT PCPN IN THE
AFTERNOON ACROSS ABOUT THE SOUTHEAST 1/3 OF THE FORECAST AREA. DID
NOT MENTION ANYTHING FOR MOST AREAS RIGHT NOW...EXCEPT NEAR THE
MISSOURI BORDER. THAT MAY NEED TO BE UPDATED LATER.
ON SUNDAY...FAIRLY WARM AIR MOVES INTO THE REGION AND SOUTHERLY
WINDS SHOULD ALLOW FOR DECENT MIXING. NET RESULT SHOULD BE HIGHS IN
THE UPPER 70S AND LOWER 80S. A COLD FRONT WILL BE MOVING TOWARD
NORTHEAST NEBRASKA THOUGH BY LATE IN THE DAY. AS THE FRONT SAGS TO
THE SOUTH SUNDAY NIGHT...IT APPEARS THAT THERE WILL BE ENOUGH
MOISTURE AND INSTABILITY FOR AT LEAST SOME SCATTERED SHOWERS AND
THUNDERSTORMS. THIS CHANCE CONTINUES INTO MONDAY. THE BEST CHANCE
APPEARS TO BE FROM NORTHEAST NEBRASKA INTO WESTERN IOWA. TIMING OF
THE FRONT...CLOUD COVER AND POSSIBLE PCPN COULD HAVE A BIG AFFECT ON
HIGHS MONDAY...BUT WENT WITH MAINLY 70S. LATEST RUNS OF THE NAM SHOW
HIGHS MAINLY IN THE 80S.
MILLER
LONG TERM...MONDAY NIGHT THROUGH THURSDAY.
THE RECENT TIMING DIFFERENCES IN THE GFS AND ECMWF WILL CONTINUE TO
BE PROBLEMATIC. LEANED MORE TOWARD A BLEND OF MODEL TIMING...BUT 12Z
ECMWF SEEMED TOO COLD AND TOO WET LATE IN THE WEEK. TEMPERATURES
WILL TURN MUCH COLDER AGAIN BY MID WEEK...WITH FAIRLY HIGH RAIN
CHANCES BEHIND THE FRONT FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT.
KEPT POPS BELOW 20 PERCENT THURSDAY AND FRIDAY...SINCE WETTER 12Z
ECMWF SOLUTION WAS NOT PREFERRED.
MILLER
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
731 PM EDT SUN APR 28 2013
.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL LIFT NORTHEAST OUT OF THE OHIO
VALLEY AND BRING SHOWERS TO WESTERN NEW YORK THROUGH THIS
EVENING. SCATTERED SHOWERS WILL LINGER LATE TONIGHT AND INTO
MONDAY. AFTER THIS...A PERSISTENT SOUTHERLY FLOW WILL BRING FAIR
AND WARM WEATHER WHICH WILL LAST THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
A CLOSED UPPER LEVEL LOW ACROSS INDIANA WILL SLOWLY MOVE TO THE
EAST THROUGH THIS EVENING. ASSOCIATED WITH THIS IS A LOW LEVEL JET
OF AROUND 40 KNOTS...WITH A STEADY AREA OF SHOWERS ACROSS
NORTHEASTERN OHIO AND WESTERN PENNSYLVANIA WHICH APPEARS TO BE
ASSOCIATED WITH THE LEADING EDGE OF THIS LOW LEVEL JET. THIS AREA OF
SHOWERS WILL CONTINUE TO GRADUALLY SPREAD INTO WESTERN NEW YORK LATE
THIS AFTERNOON THROUGH THIS EVENING. ITS PROGRESS MAY BE A BIT
SLOWER THAN PURE EXTRAPOLATION DUE TO DRYING FROM DOWNSLOPING. THIS
IS WELL CAPTURED BY THE HRRR AND MOST OTHER GUIDANCE...AND THUS HAVE
HIGH CONFIDENCE THAT THIS WILL BRING A 2-3 HOUR PERIOD OF SHOWERS TO
MOST LOCATIONS WEST OF ROCHESTER. AFTER THIS...THIS MOISTURE WILL BE
STRETCHED OUT CAUSING IT TO FALL APART AS IT APPROACHES THE EASTERN
LAKE ONTARIO REGION.
UNTIL THIS REACHES YOUR LOCATION...IT WILL CONTINUE TO BE WARM AND A BIT
BREEZY. TEMPERATURES ARE IN THE LOWER TO MID 70S IN MANY
LOCATIONS...EXPECT ABOUT 10 DEGREES COOLER IN THE SOUTHERN TIER WERE
CLOUDS CAME IN EARLY. EXPECT THE ONSET OF SHOWERS TO CAUSE A BRIEF
PERIOD OF WIND GUSTS TO 35 MPH AND A QUICK DROP IN TEMPERATURES BOTH
DUE TO EVAPORATIONAL COOLING.
AFTER THIS INITIAL ROUND OF SHOWERS MOVES THROUGH...PRECIPITATION
IS EXPECTED TO BE MUCH MORE HIT OR MISS. THIS CAN BE SEEN UPSTREAM
ON RADAR AS WELL...WITH SHOWERS BEHIND IT QUITE SCATTERED IN
NATURE. WITH THE UPPER TROF APPROACHING A SHOWER CANNOT BE RULED OUT
LATE TONIGHT...BUT EXPECT COVERAGE SOMEWHAT SPARSE. ALSO...THERE
WILL BE A LIMITED AMOUNT OF ELEVATED CAPE...WITH AN ISOLATED
THUNDERSTORM NOT COMPLETELY OUT OF THE QUESTION. FOR NOW...WILL WAIT
FOR UPSTREAM LIGHTNING STRIKES BEFORE ADDING THIS INTO THE FORECAST
GIVEN THE MARGINAL NATURE.
TEMPERATURES WILL DROP TONIGHT MAINLY BECAUSE OF EVAPORATIONAL
COOLING RATHER THAN RADIATIONAL COOLING DUE TO PERSISTENT WINDS
AND CLOUD COVER. LOWS WILL RANGE FROM THE UPPER 40S TO LOWER 50S.
ON MONDAY...THE UPPER LOW WILL CONTINUE TO OPEN UP AND LIFT
NORTHWARD. EXPECT A CONTINUING CHANCE FOR SHOWERS IN THE
MORNING...WITH THESE TAPERING OFF FROM WEST TO EAST DURING THE
AFTERNOON HOURS. TEMPERATURES WILL REMAIN ON THE WARM SIDE...WITH
HIGHS MAINLY IN THE 60S. IT COULD BE LOCALLY WARMER IF THE SUN
BREAKS OUT...BUT AT THIS TIME EXPECT THE UPPER LOW TO KEEP SKIES
CLOUDY FOR THE MAJORITY OF THE DAY.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
THE SURFACE SURFACE LOW WILL LOSE ALMOST ALL INDICATIONS BY MONDAY
NIGHT...ALL THAT REMAINS WILL BE A WEAK TROUGH ALOFT...A 25-35 KNOT
JET AT 850MB AND EXTENDED BUT WEAK CONVERGENCE IN THE LOWER LEVELS.
PRECIPITATION WILL END FROM WEST TO EAST ALTHOUGH THERE WILL BE
LINGERING CHANCE FOR SHOWER ON TUESDAY WITH DAYTIME HEATING.
HIGH PRESSURE AT THE SURFACE WILL REMAIN ANCHORED OFF THE NEW
ENGLAND COAST TUESDAY AND WEDNESDAY. AT THE SAME TIME...A RIDGE OF
HIGH PRESSURE ALOFT WILL STRENGTHEN ACROSS THE OHIO VALLEY AND
EASTERN GREAT LAKES IN RESPONSE TO A TROUGH THAT WILL BE DIGGING
INTO THE UPPER MIDWEST AND PLAINS STATES. THE HIGH SHOULD KEEP US
DRY THROUGH THIS PERIOD...ALTHOUGH WE MAY SEE A FAIR AMOUNT OF
CLOUDS AS A PERSISTENT SOUTH TO SOUTHEAST FLOW AT THE SURFACE TAPS
INTO ATLANTIC MOISTURE. THE REGION WILL ENTER A WARMER PHASE WITH
HIGH TEMPERATURES ON TUESDAY IN THE LOWER TO MID 70S...AND MID TO
UPPER 70S ON WEDNESDAY AS 850MB TEMPS RISE TO A +12C TO +14C RANGE.
SEASONABLY MILD TEMPERATURES WILL BE THE RULE TUESDAY NIGHT AND
WEDNESDAY NIGHT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE GFS AND ECMWF REMAIN IN GOOD AGREEMENT REGARDING THE POSITION
OF THE OMEGA BLOCK THAT WILL BE IN PLACE ACROSS THE EASTERN TWO
THIRDS OF THE NATION DURING THIS PERIOD. SINCE THE RIDGE OF THE
BLOCKING PATTERN IS EXPECTED TO STAY IN PLACE OVER NEW YORK STATE
AND PA...THE MOISTURE ASSOCIATED WITH THE MIDWEST CLOSED LOW SHOULD
STAY WELL TO OUR WEST. THE RIDGE WILL ALSO RESULT IN AN INCREASE IN
SUNSHINE. THIS SHOULD HELP DAYTIME TEMPERATURES HOLD IN THE LOWER
AND MID 70S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A BAND OF SHOWERS WILL PUSH ACROSS WESTERN NEW YORK THROUGH 02Z
AFFECTING THE BUF/JHW/IAG/ROC TERMINALS...BUT WITH THE SOUTHERLY
DOWNSLOPE FLOW EXPECT CIGS AND VSBY TO REMAIN IN THE VFR CATEGORY...
EXPECT FOR KJHW WHICH WILL DROP TO MVFR OR EVEN IFR.
AFTER THIS THE SHOWER ACTIVITY WILL BECOME SCATTERED...BUT COULD
POTENTIALLY BRING BRIEF PERIOD OF MODERATE TO HEAVY RAINFALL.
OTHERWISE...EXPECT MAINLY VFR CONDITIONS TONIGHT...EXPECT FOR JHW
WHERE THE SOUTHERLY FLOW DOES NOT DOWNSLOPE LIKE THE OTHER TAF
LOCATIONS. THE RAIN SHOWERS WILL BE SUPPORTED BY A LOW LEVEL
JET...WHICH WILL PRODUCE SOME LOW LEVEL WIND SHEAR TONIGHT WITH
40-45 KNOT SOUTHERLY WINDS AT 2K FEET.
FOR MONDAY...EXPECT THE MORNING TO MAINLY BE MVFR IN CIGS AS THE
FLOW BECOMES MORE SSW. SCATTERED SHOWERS WILL LINGER IN THE
MORNING...THEN TAPER OFF DURING THE AFTERNOON WITH GENERALLY
IMPROVING CONDITIONS.
OUTLOOK...
MONDAY NIGHT AND TUESDAY...MAINLY VFR. A CHANCE OF SHOWERS.
TUESDAY NIGHT THROUGH FRIDAY...VFR.
&&
.MARINE...
SOUTH TO SOUTHEAST WINDS WILL INCREASE THROUGH THIS EVENING AS THE
PRESSURE GRADIENT INCREASES ACROSS THE LOWER LAKES. WINDS MAY
APPROACH SMALL CRAFT ADVISORY CRITERIA FOR A TIME LATE TONIGHT AND
EARLY MONDAY...BUT OFFSHORE WINDS WILL KEEP THE GREATER WAVE
ACTION IN CANADIAN WATERS.
RELATIVELY LIGHT SOUTH TO SOUTHEAST WINDS ARE THEN EXPECTED TO
PERSIST FROM TUESDAY THROUGH THE END OF THE WEEK.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...APFFEL/TMA
MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
425 AM EDT SAT APR 27 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE MOVING NORTH OF LAKE ONTARIO WILL
BRING A PERIOD OF CLOUD COVER TODAY TO THE NORTH COUNTRY. OTHERWISE
THE REST OF THE AREA WILL BE MOSTLY SUNNY AS HIGH PRESSURE REMAINS
IN PLACE. THE NEXT CHANCE OF RAIN WILL ARRIVE SUNDAY NIGHT AND
MONDAY AS A WEAK AREA OF LOW PRESSURE LIFTS OUT OF THE OHIO VALLEY.
BUILDING WARMTH THIS WEEKEND WILL CONTINUE ALL OF NEXT WEEK WITH AN
EXTENDED PERIOD OF ABOVE AVERAGE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS EARLY THIS MORNING SHOWING HIGH PRESSURE IN PLACE
FROM THE LOWER LAKES INTO NEW ENGLAND. WATER VAPOR IMAGERY AND
OBJECTIVE RUC ANALYSIS SHOWING A WEAK SHORTWAVE CROSSING SOUTHERN
QUEBEC AND SOUTHEAST ONTARIO...WITH AN ASSOCIATED BAND OF MID/HIGH
CLOUDS. THIS FEATURE WILL CROSS THE NORTH COUNTRY THROUGH THE FIRST
HALF OF TODAY WITH A PERIOD OF INCREASED CLOUD COVER. UPSTREAM
RADARS DO SHOW A FEW WEAK BANDS OF SHOWERS OVER SOUTHERN ONTARIO...
BUT SHORT TERM MODEL GUIDANCE SUGGESTS THE RAIN WILL FALL APART FOR
THE MOST PART AS IT MOVES EAST INTO AN EVER DRIER AIRMASS AND
INCREASING SUBSIDENCE. WITH THIS IN MIND WILL JUST CARRY SCATTERED
SPRINKLES FOR THE NORTH COUNTRY FROM MID MORNING THROUGH MIDDAY WITH
THE PASSAGE OF THE MID LEVEL TROUGH AND ASSOCIATED PERIOD OF WEAK
ASCENT.
FOR THE REST OF THE AREA...SOME HIGH CLOUDS ON THE SOUTHERN EDGE OF
THIS SYSTEM WILL CLIP THE AREA...ESPECIALLY FROM THE THRUWAY
NORTHWARD. THESE SHOULD REMAIN THIN ENOUGH TO STILL ALLOW FOR A GOOD
AMOUNT OF SUNSHINE TO FILTER THROUGH. 850MB TEMPS RECOVER TO AROUND
+5C TODAY...WHICH WILL SUPPORT HIGHS IN THE UPPER 60S IN MANY
LOCATIONS WITH A FEW OF THE TYPICALLY WARMER SPOTS POSSIBLY REACHING
70. THE LIGHT SYNOPTIC FLOW COMBINED WITH STRONG DIFFERENTIAL
HEATING WILL SUPPORT LOCAL LAKE BREEZES BY EARLY AFTERNOON WHICH
WILL HOLD THE LAKESHORES IN THE 50S.
TONIGHT HIGH PRESSURE WILL DRIFT OFF THE EASTERN SEABOARD...ALLOWING
FOR ONGOING SOUTHERLY RETURN FLOW. THIS WILL KEEP TEMPS MILDER THAN
RECENT NIGHTS...WITH MID TO UPPER 40S ON THE LAKE PLAINS AND LOWER
40S FARTHER INLAND. A FEW OF THE COLDER SOUTHERN TIER VALLEYS AND
TUG HILL REGION WILL STILL DIP INTO THE UPPER 30S WHERE WINDS ARE
MORE LIKELY TO DECOUPLE. ANY LEFTOVER MID/HIGH CLOUDS EAST OF LAKE
ONTARIO ASSOCIATED WITH THE DEPARTING MID LEVEL SHORTWAVE SHOULD
THIN OUT OVERNIGHT AS MID LEVEL HEIGHTS RISE AND SUBSIDENCE
CONTINUES TO INCREASE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
LOW PRESSURE LOCATED OVER THE SOUTHERN PLAINS EARLY THIS SATURDAY
MORNING WILL LIFT TO THE NORTHEAST AND REACH THE OHIO VALLEY ON
SUNDAY. HIGH PRESSURE ANCHORED OFF THE EAST COAST WILL KEEP OUR AREA
DRY...BUT WARM AIR ADVECTION AHEAD OF THE APPROACHING SURFACE LOW
WILL BRING A GRADUAL INCREASE IN CLOUDS TO WESTERN NEW YORK AND THE
GENESEE VALLEY. THE SOUTHERLY FLOW BETWEEN THESE TWO SYSTEMS WILL
ALLOW TEMPERATURES TO WARM WELL INTO THE 60S...AND MAYBE EVEN LOWER
70S ALONG THE LAKE PLAINS WHERE DOWNSLOPING WINDS WILL GIVE AN ADDED
BOOST TO THE TEMPERATURES. AREAS EAST OF LAKE ONTARIO MAY ALSO WARM
INTO THE LOWER 70S DUE TO MORE SUNSHINE.
SUNDAY NIGHT AND MONDAY...THE WEAKENING SURFACE LOW WILL MOVE SLOWLY
TO THE NORTH WHILE THE UPPER LEVEL TROUGH SHIFTS EAST ACROSS NEW
YORK AND PA. A MODEST LOW LEVEL JET THAT WILL BE LIFTING NORTH
ACROSS NEW YORK STATE WILL TAP INTO THE DEEPER MOISTURE THAT WILL BE
IN PLACE OVER THE OHIO AND TENNESSEE VALLEYS. THIS WILL RESULT IN A
GRADUAL SOUTH TO NORTH INCREASE TO LIKELY POPS DURING THIS PERIOD.
IN TERMS OF QPF...THIS SYSTEM DOES NOT APPEAR AS IF IT WILL BE A BIG
RAIN MAKER...BUT IT WILL KEEP OUR WEATHER A LITTLE UNSETTLED. THE
INCREASE IN CLOUDS AND CHANCES FOR RAIN WILL KEEP TEMPERATURES A
LITTLE COOLER ON MONDAY.
THE SHOWERS WILL SHIFT SLOWLY TO THE EAST MONDAY NIGHT AND TUESDAY
AS THE UPPER TROUGH HEADS EAST TO THE NEW ENGLAND COAST. BASED ON
THIS TREND...EXPECT ANY LINGERING SHOWERS TO BE EAST OF OUR CWA BY
NOONTIME TUESDAY. THE PERSISTENT SOUTHERLY FLOW AND ANTICIPATED
TREND TOWARD SOME INCREASE IN SUNSHINE WILL ALLOW TEMPERATURES TO
WARM WELL INTO THE 60S AGAIN ON TUESDAY. DRY WEATHER AND SEASONABLY
MILD TEMPERATURES WILL CONTINUE THROUGH TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AN UPPER LEVEL TROUGH WILL DIG INTO THE NATIONS MIDSECTION DURING
THE MIDDLE OF THE WEEK...WHILE A RIDGE REMAINS IN PLACE FROM THE
MIDDLE ATLANTIC STATES TO THE CANADIAN MARITIMES. THE UPPER TROUGH
IS FORECAST TO DEEPEN FURTHER AND TRANSITION TO A CUTOFF LOW OVER
THE MID MISSISSIPPI VALLEY BY FRIDAY. THE DEEPENING TROUGH WILL HELP
TO MAINTAIN A DOWNSTREAM RIDGE OVER THE NORTHEAST AND NEW ENGLAND.
THE UPPER RIDGE SHOULD HELP TO KEEP THE STEADIER PCPN...ASSOCIATED
WITH THE UPSTREAM TROUGH...TO OUR WEST.
THE DEEP LAYERED SOUTHERLY FLOW WILL KEEP TEMPERATURES MILD THROUGH
THURSDAY. THICKENING CLOUDS AND SOME INCREASE IN CHANCE FOR SHOWERS
MAY KEEP TEMPERATURES A LITTLE COOLER ON FRIDAY. HOWEVER...IF THE
THE ECMWF`S UPPER LEVEL CONFIGURATION (WHICH FEATURES A STRONGER AND
MORE PERSISTENT UPPER LEVEL RIDGE OVER THE NORTHEAST)
VERIFIES...THEN MILDER AND DRY CONDITIONS MAY LINGER INTO FRIDAY.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
VFR WILL PREVAIL FOR THE 06Z TAF CYCLE. IR SATELLITE IMAGERY SHOWING
MAINLY CLEAR SKIES EARLY THIS MORNING...WITH JUST SOME THIN/HIGH
CIRRUS BEGINNING TO INCREASE. THESE CLOUDS WILL THICKEN AND LOWER
INTO A MID LEVEL DECK BY SATURDAY MORNING ACROSS THE NORTH COUNTRY
INCLUDING KART. THIS AREA MAY EVEN SEE A FEW SPRINKLES OR VERY LIGHT
SHOWERS THROUGH THE FIRST HALF OF SATURDAY...BUT THESE WILL REMAIN
LIGHT ENOUGH TO KEEP VSBY VFR. OTHERWISE THE REST OF THE AREA WILL
JUST SEE SCT CIRRUS LEVEL CLOUDINESS. THE LIGHT BACKGROUND WINDS
WILL ALLOW LOCAL LAKE BREEZES TO DEVELOP DURING THE AFTERNOON WITH
WIND SHIFTS LIKELY OCCURRING WITHIN 10-20 MILES OF THE LAKESHORES.
OUTLOOK...
SUNDAY AND SUNDAY NIGHT...MOSTLY VFR WITH SHOWERS LIKELY DEVELOPING
SUNDAY AFTERNOON AND NIGHT.
MONDAY...MOSTLY VFR WITH A CHANCE OF SHOWERS.
TUESDAY THROUGH WEDNESDAY...VFR.
&&
.MARINE...
HIGH PRESSURE IN PLACE FROM THE OHIO VALLEY TO THE NORTHEAST WILL
PROVIDE LIGHT WINDS TODAY AND TONIGHT. STRONG DIFFERENTIAL HEATING
TODAY WILL SUPPORT LAKE BREEZE DEVELOPMENT BY EARLY AFTERNOON WITH
WINDS BECOMING LOCALLY ONSHORE ON BOTH LAKES ERIE AND ONTARIO. BY
SUNDAY NIGHT AND MONDAY HIGH PRESSURE WILL DRIFT OFF THE EAST COAST.
THIS WILL ALLOW THE PRESSURE GRADIENT TO INCREASE SOMEWHAT...WITH
SOUTH TO SOUTHEAST WINDS INCREASING BUT STILL REMAINING WELL BELOW
SMALL CRAFT ADVISORY CRITERIA. SOUTH TO SOUTHEAST WINDS WILL REMAIN
IN PLACE MUCH OF NEXT WEEK WITH GENERALLY LIGHT WAVE ACTION GIVEN
THE OFFSHORE FLOW.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...HITCHCOCK
NEAR TERM...HITCHCOCK
SHORT TERM...TJP
LONG TERM...TJP
AVIATION...HITCHCOCK
MARINE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1020 AM EDT SAT APR 27 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE TODAY. PASSING SHOWERS WILL
DEVELOP INLAND LATER THIS AFTERNOON AND OVERNIGHT. SEVERAL
DISTURBANCES MOVING EAST ACROSS THE GULF STATES WILL LEAD TO
INCREASING CLOUDS SUNDAY AND ELEVATED RAIN CHANCES LATE SUNDAY
AND MONDAY. A SLIGHT DRYING TREND IS EXPECTED DURING THE MIDDLE OF
NEXT WEEK WITH AN APPROACHING COLD FRONT LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM SATURDAY...THE SHOWERS OVER SOUTH CAROLINA CONTINUE TO
WEAKEN AS THEY MOVE INTO THE DRIER AIR TO THE EAST. THE NAM AND
LATEST RUC ALL ARE SHOWING THE COLUMN FROM 700 MB TO 600 MB
MOISTENING UP WITH THE ONLY MINOR LIFT ABOVE 700 MB. CLOUD COVER
WILL STAY OVER THE SOUTHERN 2/3 OF THE AREA WITH PORTIONS OF
SOUTHEAST NORTH CAROLINA SEEING A FEW MORE BREAKS IN THE CLOUDS
THIS AFTERNOON.
THE 09 UTC SREF IS SHOWING THE PROBABILITY OF 12H PCPN GREATER
THAN 0.01 INCHES TO BE HIGH THIS EVENING AND MAINLY NORTH AND WEST
OF INTERSTATE 20 AND INTERSTATE 95. THE 0.10 INCH PROBABILITY 70%
CHANCE IS JUST WEST OF OUR FORECASTER. AS MENTIONED IN PREVIOUS
DISCUSSION THE LIFT IS ELEVATED AND THE CHANCE OF HEAVY RAIN OR
VERY REMOTE, BUT THE CHANCE OF MEASURABLE PRECIPITATION OUT WEST
INCREASES INTO THE EVENING HOURS.
THERE WERE NO CHANGES ON THE HIGH WITH MAXIMUM TEMPERATURES
REACHING THE LOWER 70S AND TONIGHT THE LOWS ARE EXPECTED TO FALL
TO THE 50-55 DEGREE RANGE.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SURFACE AND MID LEVEL RIDGE AXIS SHIFT
OFFSHORE EARLY IN THE PERIOD ALLOWING DEEP RETURN FLOW. PLENTY OF
DEEP MOISTURE IN PLACE WITH 850-500 LAYER RH VALUES GREATER THAN 75%
FOR THE DURATION OF THE PERIOD. ALTHOUGH SIGNIFICANT DYNAMICAL
FEATURES ARE LACKING THE FLOW ALOFT IS DIVERGENT. ADDITIONALLY THERE
ARE LIKELY TO BE WEAK AREAS OF POSITIVE VORTICITY ADVECTION ROTATING
THROUGH SHORTWAVE TROUGH TO THE WEST. TIMING THESE FEATURES 2 AND 3
DAYS OUT IS DIFFICULT AT BEST BUT THESE WOULD CERTAINLY HELP ENHANCE
ANY ONGOING CONVECTION AS THEY MOVE INTO THE AREA. ALTHOUGH
CONVECTIVE PARAMETERS ARE LIMITED LOW LEVEL CONVERGENCE COMBINED
WITH DIURNAL INSTABILITY SHOULD GENERATE SHOWERS. BEST PRECIP
CHANCES APPEAR TO BE EARLY MON AND MON NIGHT WITH ENHANCED
DIVERGENCE ALOFT AND INCREASED DEEP MOISTURE. HIGHS WILL FALL A
LITTLE SHORT OF CLIMO GIVEN INCREASED CLOUD COVER AND RAIN CHANCES.
ABUNDANT MOISTURE WILL KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...MEDIUM RANGE GUIDANCE CONTINUES TO HAVE
PROBLEMS WITH EVOLUTION OF MID LEVEL PATTERN OVER THE CONUS NEXT
WEEK. HOWEVER SOME NUGGETS OF INFORMATION CAN BE GLEANED FROM THE
CHAOS. EARLY IN THE PERIOD WEAK PATTERN ALOFT AND COASTAL TROUGH
LEAD TO DIURNAL CONVECTION...THOUGH COVERAGE WILL BE LIMITED BY MID
LEVEL DRY AIR. BY THE MIDDLE OF NEXT WEEK THERE WILL BE A SOUTHERN
STREAM SYSTEM CROSSING THE NORTHERN GULF OF MEXICO. AT THE SAME TIME
A SIGNIFICANT COLD FRONT WILL BE DRIVEN ACROSS THE CENTRAL US BY
LONGWAVE MID LEVEL TROUGH. LATE IN THE PERIOD BOTH ECMWF AND GFS
HINT AT SOUTHERN STREAM SHORTWAVE INDUCING A COASTAL LOW OFF THE
SOUTHEAST COAST WHICH IS THEN LIFTED NORTH AHEAD OF THE COLD FRONT.
DESPITE SIMILARITIES BETWEEN THE GFS/ECMWF THERE REMAIN PLENTY OF
MAJOR DIFFERENCES. BOTH MODELS SHOW THE MID LEVEL TROUGH BECOMING
CUTOFF BUT DO SO AT DIFFERENT TIMES AND LOCATIONS. THE GFS IS SLOWER
TO CUTOFF THE 5H TROUGH AND THUS IS FARTHER EAST. GIVEN THE
UNCERTAINTY WILL KEEP POP CAPPED AT CHANCE WITH HIGHEST VALUES
DURING THE DAY. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...VFR AT ALL TERMS THIS MORNING WITH INCREASING MID-
LEVEL CLOUDS AHEAD OF A LOW PRESSURE SYSTEM NEAR TX/AR. RAINFALL
FROM THE WESTERN CAROLINAS IS GENERALLY DISSIPATING AS IT NEARS
OUR CWA...SO DO NOT EXPECT ANY NEAR-TERM IMPACTS TO OUR TAF SITES.
CLOUD COVER WILL PERSIST FOR MUCH OF THE PERIOD WITH 10-15KFT CIGS
AND SCT LOWER CLOUDS AS WELL. LIGHT NE WINDS THIS MORNING WILL
BECOME E/SE 10-12 KTS IN THE AFTN. RAIN CHANCES INCREASE LATER THIS
AFTN AS MOIST ISENTROPIC LIFT COULD RESULT IN SOME SHOWER ACTIVITY
INLAND...MOST LIKELY AT KFLO. THE BEST LIFT WILL LIKELY REMAIN TO
THE WEST OF OUR CWA...BUT HAVE INCLUDED VCSH FOR KFLO/KLBT THRU THE
AFTN/EVENING HOURS. CANNOT RULE OUT A STRAY SHOWER AFTER 00Z ALONG
THE COAST...BUT CHOSE NOT TO MENTION PCPN FOR THE COASTAL SITES ATTM.
EXTENDED OUTLOOK...UNSETTLED WEATHER WILL RESULT IN PERIODS OF RAIN
WITH SUB-VFR CONDITIONS POSSIBLE SUNDAY THROUGH WEDNESDAY. BEST RAIN
CHANCES LOOK TO BE ON MONDAY ASSOCIATED WITH A SHORTWAVE TROUGH.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10115 AM SATURDAY...HIGH PRESSURE WELL TO THE NORTH WILL
CONTINUE TO INFLUENCE THE COASTAL MARINE WATERS. NORTHEAST WINDS
ARE EXPECTED TO VEER TO THE EAST BY THIS AFTERNOON. WINDS SPEEDS
ARE EXPECTED TO INCREASE TO 10 TO 15 KNOTS AND SEAS WILL INCREASE TO
4 FEET.. WITH TO 2 TO 3 FEET NEAR THE BRUNSWICK COUNTY COAST.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...LIGHT EASTERLY FLOW AT THE START OF THE PERIOD
QUICKLY BECOMES SOUTHEAST AS SURFACE RIDGE AXIS SHIFTS EAST OF THE
WATERS. ONLY SUBTLE CHANGES TO THE GRADIENT EXPECTED DURING THE
PERIOD WITH SEA-BREEZE DEVELOPMENT ENHANCING SPEEDS SLIGHTLY. SPEEDS
WILL REMAIN IN THE 10 TO 15 KT RANGE WITH SEAS RUNNING 3 TO 5 FT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...SOUTHERLY FLOW CONTINUES THROUGH THE PERIOD
WITH SURFACE HIGH CENTERED NORTHEAST OF THE WATERS BEING THE
DOMINANT FEATURE. GRADIENT REMAINS ON THE WEAK SIDE WITH SPEEDS
STRUGGLING TO REACH 15 KT EVEN WITH THE HELP OF SEABREEZE
ENHANCEMENT. SEAS WILL RUN 3 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HAWKINS
SHORT TERM...III
LONG TERM...III
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
743 AM EDT SAT APR 27 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE TODAY. PASSING SHOWERS WILL
DEVELOP INLAND LATER THIS AFTERNOON AND OVERNIGHT. SEVERAL
DISTURBANCES MOVING EAST ACROSS THE GULF STATES WILL LEAD TO
INCREASING CLOUDS SUNDAY AND ELEVATED RAIN CHANCES LATE SUNDAY
AND MONDAY. A SLIGHT DRYING TREND IS EXPECTED DURING THE MIDDLE OF
NEXT WEEK WITH AN APPROACHING COLD FRONT LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...THE FIRST WAVE OF RAINFALL ACROSS SOUTH
CAROLINA IS DIMINISHING AS EXPECTED AS IT ENCOUNTERS DEEP DRY AIR
OVER THE EASTERN PIEDMONT AND COASTAL PLAINS. IT APPEARS MEASURABLE
RAINFALL WILL REMAIN SOUTH AND WEST OF KINGSTREE SO I HAVE REMOVED
THE SMALL 20 POP ALONG THE SANTEE RIVER FOR THIS MORNING. 06Z MODELS
HAVE CHANGED LITTLE WITH THEIR DEPICTION OF THIS EVENING`S NEXT WAVE
OF RAIN ACROSS THE PEE DEE REGION SO LITTLE CHANGE HAS BEEN MADE TO
THE FORECAST BEYOND THIS MORNING. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
SURFACE HIGH PRESSURE WILL MOVE OFF THE NEW ENGLAND COASTLINE AND
INTO THE NORTH ATLANTIC THIS AFTERNOON. THIS WILL MAINTAIN A FAIRLY
DRY NORTHEAST TO EAST LOW-LEVEL FLOW INTO THE EASTERN CAROLINAS
THROUGH TONIGHT. SURFACE LOW PRESSURE ALONG THE TX-OK BORDER THIS
MORNING WILL MOVE INTO SOUTHERN ILLINOIS LATE TONIGHT. THIS LOW IS
BEING MAINTAINED BY A SHORTWAVE TROUGH ALMOST CUT OFF FROM THE MAIN
JET STREAM FLOW WELL TO THE NORTH ACROSS THE NORTHERN UNITED STATES.
THICKENING HIGH AND MID LEVEL CLOUDS EARLY THIS MORNING ARE BEING
PRODUCED BY PACIFIC AND NOW GULF MOISTURE BEING ADVECTED OUT AHEAD
OF THE SHORTWAVE DISTURBANCE. DRY LOW LEVELS OF THE ATMOSPHERE PLUS
AND A PERSISTENT MID TO UPPER LEVEL RIDGE ACROSS THE SOUTHERN
APPALACHIANS ARE HELPING ERODE PRECIPITATION THAT IS TRYING TO
STREAM EAST-SOUTHEAST FROM KENTUCKY AND TENNESSEE. RADAR COMPOSITES
SHOW A NARROW BUT IMPRESSIVE AREA OF MODERATE TO HEAVY RAINFALL
ACROSS NORTHERN GEORGIA THAT LOOKS TO BE MOVING IN THE GENERAL
DIRECTION OF THE SANTEE RIVER BASIN. IF ANY OF THIS PRECIPITATION
SURVIVES OUR DRY AIR...IT WOULD REACH WILLIAMSBURG AND GEORGETOWN
COUNTIES BETWEEN 6-9 AM. THE 04Z HRRR APPEARS TO HAVE A GOOD HANDLE
ON THIS PRECIPITATION AND SHOWS ONLY A COUPLE HUNDREDTHS OF AN INCH
SCATTERED ALONG THE SANTEE RIVER LATER THIS MORNING.
PARTLY TO MOSTLY CLOUDY SKIES WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON HOURS. HIGH SUN ANGLES (SAME AS IN MID AUGUST) WILL CUT
THROUGH THE CLOUDS AND PUSH TEMPERATURES INTO THE LOWER TO MID 70S
AWAY FROM THE BEACHES.
AN INTERESTING SITUATION WILL DEVELOP ACROSS CENTRAL SOUTH CAROLINA
LATE THIS AFTERNOON AS THE GFS AND ECMWF SHOW A NARROW ZONE OF
RATHER IMPRESSIVE ISENTROPIC LIFT DEVELOPING ALONG THE 305-310K
THETA SURFACES...APPROXIMATELY 12000-16000 FT AGL. THIS IS MUCH
HIGHER UP THAN WHERE I TYPICALLY ANALYZE ISENTROPIC LIFT BUT APPEARS
TO BE WHAT THE MODELS ARE LATCHING ONTO FOR THE DEVELOPMENT OF RAIN
THAT MAY AFFECT THE SC PEE DEE REGION JUST BEFORE SUNSET. I HAVE
INCREASED POPS TO 30-40 PERCENT MAINLY BETWEEN 5-9 PM...WITH MODELS
INDICATING THAT AGAIN THE RAIN WILL DRY UP AS IT TRIES TO MOVE EAST
TOWARD THE COAST. PERHAPS EVEN MORE INTERESTING IS THE POTENTIAL FOR
SMALL ELEVATED INSTABILITY ORIGINATING FROM VERY HIGH ALOFT...
500-550 MB. IT IS QUITE RARE FOR CONVECTION TO DEVELOP FROM SUCH A
HIGH BASE IN THIS PART OF THE COUNTRY...BUT THIS COULD ADD A LITTLE
CONVECTIVE CHARACTER TO WHAT MAY BE AN OTHERWISE STRATIFORM RAIN
EVENT. EVEN THE MOST AGGRESSIVE MODEL SHOWS CAPE LESS THAN 100 J/KG
SO WE`RE NOT TALKING ABOUT SEVERE WEATHER BY ANY STRETCH.
PRECIPITATION SHOULD DIMINISH IN COVERAGE DURING THE LATE EVENING
HOURS...BUT WITH PLENTY OF CLOUDS REMAINING OVERNIGHT. LOWS SHOULD
FALL TO 50-55...WARMEST ALONG THE SC COAST WITH THE ONSHORE WIND AND
ALSO BACK UNDER THE CLOUDS ACROSS THE PEE DEE REGION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SURFACE AND MID LEVEL RIDGE AXIS SHIFT
OFFSHORE EARLY IN THE PERIOD ALLOWING DEEP RETURN FLOW. PLENTY OF
DEEP MOISTURE IN PLACE WITH 850-500 LAYER RH VALUES GREATER THAN 75%
FOR THE DURATION OF THE PERIOD. ALTHOUGH SIGNIFICANT DYNAMICAL
FEATURES ARE LACKING THE FLOW ALOFT IS DIVERGENT. ADDITIONALLY THERE
ARE LIKELY TO BE WEAK AREAS OF POSITIVE VORTICITY ADVECTION ROTATING
THROUGH SHORTWAVE TROUGH TO THE WEST. TIMING THESE FEATURES 2 AND 3
DAYS OUT IS DIFFICULT AT BEST BUT THESE WOULD CERTAINLY HELP ENHANCE
ANY ONGOING CONVECTION AS THEY MOVE INTO THE AREA. ALTHOUGH
CONVECTIVE PARAMETERS ARE LIMITED LOW LEVEL CONVERGENCE COMBINED
WITH DIURNAL INSTABILITY SHOULD GENERATE SHOWERS. BEST PRECIP
CHANCES APPEAR TO BE EARLY MON AND MON NIGHT WITH ENHANCED
DIVERGENCE ALOFT AND INCREASED DEEP MOISTURE. HIGHS WILL FALL A
LITTLE SHORT OF CLIMO GIVEN INCREASED CLOUD COVER AND RAIN CHANCES.
ABUNDANT MOISTURE WILL KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...MEDIUM RANGE GUIDANCE CONTINUES TO HAVE
PROBLEMS WITH EVOLUTION OF MID LEVEL PATTERN OVER THE CONUS NEXT
WEEK. HOWEVER SOME NUGGETS OF INFORMATION CAN BE GLEANED FROM THE
CHAOS. EARLY IN THE PERIOD WEAK PATTERN ALOFT AND COASTAL TROUGH
LEAD TO DIURNAL CONVECTION...THOUGH COVERAGE WILL BE LIMITED BY MID
LEVEL DRY AIR. BY THE MIDDLE OF NEXT WEEK THERE WILL BE A SOUTHERN
STREAM SYSTEM CROSSING THE NORTHERN GULF OF MEXICO. AT THE SAME TIME
A SIGNIFICANT COLD FRONT WILL BE DRIVEN ACROSS THE CENTRAL US BY
LONGWAVE MID LEVEL TROUGH. LATE IN THE PERIOD BOTH ECMWF AND GFS
HINT AT SOUTHERN STREAM SHORTWAVE INDUCING A COASTAL LOW OFF THE
SOUTHEAST COAST WHICH IS THEN LIFTED NORTH AHEAD OF THE COLD FRONT.
DESPITE SIMILARITIES BETWEEN THE GFS/ECMWF THERE REMAIN PLENTY OF
MAJOR DIFFERENCES. BOTH MODELS SHOW THE MID LEVEL TROUGH BECOMING
CUTOFF BUT DO SO AT DIFFERENT TIMES AND LOCATIONS. THE GFS IS SLOWER
TO CUTOFF THE 5H TROUGH AND THUS IS FARTHER EAST. GIVEN THE
UNCERTAINTY WILL KEEP POP CAPPED AT CHANCE WITH HIGHEST VALUES
DURING THE DAY. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...VFR AT ALL TERMS THIS MORNING WITH INCREASING MID-LEVEL
CLOUDS AHEAD OF A LOW PRESSURE SYSTEM NEAR TX/AR. RAINFALL FROM
THE WESTERN CAROLINAS IS GENERALLY DISSIPATING AS IT NEARS OUR
CWA...SO DO NOT EXPECT ANY NEAR-TERM IMPACTS TO OUR TAF SITES.
CLOUD COVER WILL PERSIST FOR MUCH OF THE PERIOD WITH 10-15KFT CIGS
AND SCT LOWER CLOUDS AS WELL. LIGHT NE WINDS THIS MORNING WILL
BECOME E/SE 10-12 KTS IN THE AFTN. RAIN CHANCES INCREASE LATER THIS
AFTN AS MOIST ISENTROPIC LIFT COULD RESULT IN SOME SHOWER ACTIVITY
INLAND...MOST LIKELY AT KFLO. THE BEST LIFT WILL LIKELY REMAIN TO
THE WEST OF OUR CWA...BUT HAVE INCLUDED VCSH FOR KFLO/KLBT THRU THE
AFTN/EVENING HOURS. CANNOT RULE OUT A STRAY SHOWER AFTER 00Z ALONG
THE COAST...BUT CHOSE NOT TO MENTION PCPN FOR THE COASTAL SITES ATTM.
EXTENDED OUTLOOK...UNSETTLED WEATHER WILL RESULT IN PERIODS OF RAIN
WITH SUB-VFR CONDITIONS POSSIBLE SUNDAY THROUGH WEDNESDAY. BEST RAIN
CHANCES LOOK TO BE ON MONDAY ASSOCIATED WITH A SHORTWAVE TROUGH.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...6 AM OBSERVATIONS OF WIND AND SEAS WERE
RIGHT ON THE MONEY...SO NO CHANGES HAVE BEEN MADE FROM THE PREVIOUS
FORECAST. DISCUSSION FROM 300 AM FOLLOWS...
STRONG HIGH PRESSURE OVER NEW ENGLAND WILL MOVE EAST AND INTO THE
NORTH ATLANTIC LATER TODAY. THE HIGH WILL CONTINUE TO RIDGE
SOUTHWARD TOWARD THE CAROLINAS WITH NORTHEAST TO EAST WIND
CONTINUING. WIND SPEEDS SHOULD REMAIN A VERY CONSISTENT 10-15 KNOTS
THROUGH TONIGHT...WHICH GIVEN THE LONG FETCH ORIGINATING FROM
NEWFOUNDLAND IS ENOUGH TO MAINTAIN A NEARLY STEADY SEA STATE OF 3-4
FT NORTH OF CAPE FEAR AND EAST OF GEORGETOWN...WITH 2-4 FT SEAS
ELSEWHERE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...LIGHT EASTERLY FLOW AT THE START OF THE PERIOD
QUICKLY BECOMES SOUTHEAST AS SURFACE RIDGE AXIS SHIFTS EAST OF THE
WATERS. ONLY SUBTLE CHANGES TO THE GRADIENT EXPECTED DURING THE
PERIOD WITH SEABREEZE DEVELOPMENT ENHANCING SPEEDS SLIGHTLY. SPEEDS
WILL REMAIN IN THE 10 TO 15 KT RANGE WITH SEAS RUNNING 3 TO 5 FT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...SOUTHERLY FLOW CONTINUES THROUGH THE PERIOD
WITH SURFACE HIGH CENTERED NORTHEAST OF THE WATERS BEING THE
DOMINANT FEATURE. GRADIENT REMAINS ON THE WEAK SIDE WITH SPEEDS
STRUGGLING TO REACH 15 KT EVEN WITH THE HELP OF SEABREEZE
ENHANCEMENT. SEAS WILL RUN 3 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 AM EDT SAT APR 27 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE TODAY. PASSING SHOWERS WILL
DEVELOP INLAND LATER THIS AFTERNOON AND OVERNIGHT. SEVERAL
DISTURBANCES MOVING EAST ACROSS THE GULF STATES WILL LEAD TO
INCREASING CLOUDS SUNDAY AND ELEVATED RAIN CHANCES LATE SUNDAY
AND MONDAY. A SLIGHT DRYING TREND IS EXPECTED DURING THE MIDDLE OF
NEXT WEEK WITH AN APPROACHING COLD FRONT LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...THE FIRST WAVE OF RAINFALL ACROSS SOUTH
CAROLINA IS DIMINISHING AS EXPECTED AS IT ENCOUNTERS DEEP DRY AIR
OVER THE EASTERN PIEDMONT AND COASTAL PLAINS. IT APPEARS MEASURABLE
RAINFALL WILL REMAIN SOUTH AND WEST OF KINGSTREE SO I HAVE REMOVED
THE SMALL 20 POP ALONG THE SANTEE RIVER FOR THIS MORNING. 06Z MODELS
HAVE CHANGED LITTLE WITH THEIR DEPICTION OF THIS EVENING`S NEXT WAVE
OF RAIN ACROSS THE PEE DEE REGION SO LITTLE CHANGE HAS BEEN MADE TO
THE FORECAST BEYOND THIS MORNING. PREVIOUS DISCUSSION FROM 300 AM
FOLLOWS...
SURFACE HIGH PRESSURE WILL MOVE OFF THE NEW ENGLAND COASTLINE AND
INTO THE NORTH ATLANTIC THIS AFTERNOON. THIS WILL MAINTAIN A FAIRLY
DRY NORTHEAST TO EAST LOW-LEVEL FLOW INTO THE EASTERN CAROLINAS
THROUGH TONIGHT. SURFACE LOW PRESSURE ALONG THE TX-OK BORDER THIS
MORNING WILL MOVE INTO SOUTHERN ILLINOIS LATE TONIGHT. THIS LOW IS
BEING MAINTAINED BY A SHORTWAVE TROUGH ALMOST CUT OFF FROM THE MAIN
JET STREAM FLOW WELL TO THE NORTH ACROSS THE NORTHERN UNITED STATES.
THICKENING HIGH AND MID LEVEL CLOUDS EARLY THIS MORNING ARE BEING
PRODUCED BY PACIFIC AND NOW GULF MOISTURE BEING ADVECTED OUT AHEAD
OF THE SHORTWAVE DISTURBANCE. DRY LOW LEVELS OF THE ATMOSPHERE PLUS
AND A PERSISTENT MID TO UPPER LEVEL RIDGE ACROSS THE SOUTHERN
APPALACHIANS ARE HELPING ERODE PRECIPITATION THAT IS TRYING TO
STREAM EAST-SOUTHEAST FROM KENTUCKY AND TENNESSEE. RADAR COMPOSITES
SHOW A NARROW BUT IMPRESSIVE AREA OF MODERATE TO HEAVY RAINFALL
ACROSS NORTHERN GEORGIA THAT LOOKS TO BE MOVING IN THE GENERAL
DIRECTION OF THE SANTEE RIVER BASIN. IF ANY OF THIS PRECIPITATION
SURVIVES OUR DRY AIR...IT WOULD REACH WILLIAMSBURG AND GEORGETOWN
COUNTIES BETWEEN 6-9 AM. THE 04Z HRRR APPEARS TO HAVE A GOOD HANDLE
ON THIS PRECIPITATION AND SHOWS ONLY A COUPLE HUNDREDTHS OF AN INCH
SCATTERED ALONG THE SANTEE RIVER LATER THIS MORNING.
PARTLY TO MOSTLY CLOUDY SKIES WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON HOURS. HIGH SUN ANGLES (SAME AS IN MID AUGUST) WILL CUT
THROUGH THE CLOUDS AND PUSH TEMPERATURES INTO THE LOWER TO MID 70S
AWAY FROM THE BEACHES.
AN INTERESTING SITUATION WILL DEVELOP ACROSS CENTRAL SOUTH CAROLINA
LATE THIS AFTERNOON AS THE GFS AND ECMWF SHOW A NARROW ZONE OF
RATHER IMPRESSIVE ISENTROPIC LIFT DEVELOPING ALONG THE 305-310K
THETA SURFACES...APPROXIMATELY 12000-16000 FT AGL. THIS IS MUCH
HIGHER UP THAN WHERE I TYPICALLY ANALYZE ISENTROPIC LIFT BUT APPEARS
TO BE WHAT THE MODELS ARE LATCHING ONTO FOR THE DEVELOPMENT OF RAIN
THAT MAY AFFECT THE SC PEE DEE REGION JUST BEFORE SUNSET. I HAVE
INCREASED POPS TO 30-40 PERCENT MAINLY BETWEEN 5-9 PM...WITH MODELS
INDICATING THAT AGAIN THE RAIN WILL DRY UP AS IT TRIES TO MOVE EAST
TOWARD THE COAST. PERHAPS EVEN MORE INTERESTING IS THE POTENTIAL FOR
SMALL ELEVATED INSTABILITY ORIGINATING FROM VERY HIGH ALOFT...
500-550 MB. IT IS QUITE RARE FOR CONVECTION TO DEVELOP FROM SUCH A
HIGH BASE IN THIS PART OF THE COUNTRY...BUT THIS COULD ADD A LITTLE
CONVECTIVE CHARACTER TO WHAT MAY BE AN OTHERWISE STRATIFORM RAIN
EVENT. EVEN THE MOST AGGRESSIVE MODEL SHOWS CAPE LESS THAN 100 J/KG
SO WE`RE NOT TALKING ABOUT SEVERE WEATHER BY ANY STRETCH.
PRECIPITATION SHOULD DIMINISH IN COVERAGE DURING THE LATE EVENING
HOURS...BUT WITH PLENTY OF CLOUDS REMAINING OVERNIGHT. LOWS SHOULD
FALL TO 50-55...WARMEST ALONG THE SC COAST WITH THE ONSHORE WIND AND
ALSO BACK UNDER THE CLOUDS ACROSS THE PEE DEE REGION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SURFACE AND MID LEVEL RIDGE AXIS SHIFT
OFFSHORE EARLY IN THE PERIOD ALLOWING DEEP RETURN FLOW. PLENTY OF
DEEP MOISTURE IN PLACE WITH 850-500 LAYER RH VALUES GREATER THAN 75%
FOR THE DURATION OF THE PERIOD. ALTHOUGH SIGNIFICANT DYNAMICAL
FEATURES ARE LACKING THE FLOW ALOFT IS DIVERGENT. ADDITIONALLY THERE
ARE LIKELY TO BE WEAK AREAS OF POSITIVE VORTICITY ADVECTION ROTATING
THROUGH SHORTWAVE TROUGH TO THE WEST. TIMING THESE FEATURES 2 AND 3
DAYS OUT IS DIFFICULT AT BEST BUT THESE WOULD CERTAINLY HELP ENHANCE
ANY ONGOING CONVECTION AS THEY MOVE INTO THE AREA. ALTHOUGH
CONVECTIVE PARAMETERS ARE LIMITED LOW LEVEL CONVERGENCE COMBINED
WITH DIURNAL INSTABILITY SHOULD GENERATE SHOWERS. BEST PRECIP
CHANCES APPEAR TO BE EARLY MON AND MON NIGHT WITH ENHANCED
DIVERGENCE ALOFT AND INCREASED DEEP MOISTURE. HIGHS WILL FALL A
LITTLE SHORT OF CLIMO GIVEN INCREASED CLOUD COVER AND RAIN CHANCES.
ABUNDANT MOISTURE WILL KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...MEDIUM RANGE GUIDANCE CONTINUES TO HAVE
PROBLEMS WITH EVOLUTION OF MID LEVEL PATTERN OVER THE CONUS NEXT
WEEK. HOWEVER SOME NUGGETS OF INFORMATION CAN BE GLEANED FROM THE
CHAOS. EARLY IN THE PERIOD WEAK PATTERN ALOFT AND COASTAL TROUGH
LEAD TO DIURNAL CONVECTION...THOUGH COVERAGE WILL BE LIMITED BY MID
LEVEL DRY AIR. BY THE MIDDLE OF NEXT WEEK THERE WILL BE A SOUTHERN
STREAM SYSTEM CROSSING THE NORTHERN GULF OF MEXICO. AT THE SAME TIME
A SIGNIFICANT COLD FRONT WILL BE DRIVEN ACROSS THE CENTRAL US BY
LONGWAVE MID LEVEL TROUGH. LATE IN THE PERIOD BOTH ECMWF AND GFS
HINT AT SOUTHERN STREAM SHORTWAVE INDUCING A COASTAL LOW OFF THE
SOUTHEAST COAST WHICH IS THEN LIFTED NORTH AHEAD OF THE COLD FRONT.
DESPITE SIMILARITIES BETWEEN THE GFS/ECMWF THERE REMAIN PLENTY OF
MAJOR DIFFERENCES. BOTH MODELS SHOW THE MID LEVEL TROUGH BECOMING
CUTOFF BUT DO SO AT DIFFERENT TIMES AND LOCATIONS. THE GFS IS SLOWER
TO CUTOFF THE 5H TROUGH AND THUS IS FARTHER EAST. GIVEN THE
UNCERTAINTY WILL KEEP POP CAPPED AT CHANCE WITH HIGHEST VALUES
DURING THE DAY. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...VFR THROUGH THE PERIOD. INCREASING RAIN CHANCES TONIGHT.
HIGH AND MID CLOUDS WILL CONTINUE TO THICKEN ACROSS THE AREA. LATEST
HIGH-RES MODELS INDICATE MODERATE TO HEAVY RAIN ACROSS S TN AND N GA
MAY MAKE A RUN TOWARD THE FLORENCE AIRPORT 10-13Z. I WILL MONITOR
CLOSELY TO SEE IF RAIN NEEDS TO BE ADDED TO OUR TAF FORECAST.
OTHERWISE RAIN CHANCES INCREASE FOR THE INLAND TERMINALS TOWARDS THE
EVENING HOURS...AND THEN FOR THE COASTAL TERMINALS INTO THE
OVERNIGHT HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER SATURDAY NIGHT THROUGH TUESDAY
AS AN OVERRUNNING SCENARIO GIVES US MOSTLY CLOUDY CONDITIONS THROUGH
WEDNESDAY WITH PERIODS OF RAIN AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM SATURDAY...6 AM OBSERVATIONS OF WIND AND SEAS WERE
RIGHT ON THE MONEY...SO NO CHANGES HAVE BEEN MADE FROM THE PREVIOUS
FORECAST. DISCUSSION FROM 300 AM FOLLOWS...
STRONG HIGH PRESSURE OVER NEW ENGLAND WILL MOVE EAST AND INTO THE
NORTH ATLANTIC LATER TODAY. THE HIGH WILL CONTINUE TO RIDGE
SOUTHWARD TOWARD THE CAROLINAS WITH NORTHEAST TO EAST WIND
CONTINUING. WIND SPEEDS SHOULD REMAIN A VERY CONSISTENT 10-15 KNOTS
THROUGH TONIGHT...WHICH GIVEN THE LONG FETCH ORIGINATING FROM
NEWFOUNDLAND IS ENOUGH TO MAINTAIN A NEARLY STEADY SEA STATE OF 3-4
FT NORTH OF CAPE FEAR AND EAST OF GEORGETOWN...WITH 2-4 FT SEAS
ELSEWHERE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...LIGHT EASTERLY FLOW AT THE START OF THE PERIOD
QUICKLY BECOMES SOUTHEAST AS SURFACE RIDGE AXIS SHIFTS EAST OF THE
WATERS. ONLY SUBTLE CHANGES TO THE GRADIENT EXPECTED DURING THE
PERIOD WITH SEABREEZE DEVELOPMENT ENHANCING SPEEDS SLIGHTLY. SPEEDS
WILL REMAIN IN THE 10 TO 15 KT RANGE WITH SEAS RUNNING 3 TO 5 FT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...SOUTHERLY FLOW CONTINUES THROUGH THE PERIOD
WITH SURFACE HIGH CENTERED NORTHEAST OF THE WATERS BEING THE
DOMINANT FEATURE. GRADIENT REMAINS ON THE WEAK SIDE WITH SPEEDS
STRUGGLING TO REACH 15 KT EVEN WITH THE HELP OF SEABREEZE
ENHANCEMENT. SEAS WILL RUN 3 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
329 AM EDT SAT APR 27 2013
.SYNOPSIS...
CLOUDS WILL BE ON THE INCREASE TODAY. PASSING SHOWERS WILL
DEVELOP INLAND LATER THIS AFTERNOON AND OVERNIGHT. SEVERAL
DISTURBANCES MOVING EAST ACROSS THE GULF STATES WILL LEAD TO
INCREASING CLOUDS SUNDAY AND ELEVATED RAIN CHANCES LATE SUNDAY
AND MONDAY. A SLIGHT DRYING TREND IS EXPECTED DURING THE MIDDLE OF
NEXT WEEK WITH AN APPROACHING COLD FRONT LATE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SATURDAY...SURFACE HIGH PRESSURE WILL MOVE OFF THE NEW
ENGLAND COASTLINE AND INTO THE NORTH ATLANTIC THIS AFTERNOON. THIS
WILL MAINTAIN A FAIRLY DRY NORTHEAST TO EAST LOW-LEVEL FLOW INTO
THE EASTERN CAROLINAS THROUGH TONIGHT. SURFACE LOW PRESSURE ALONG
THE TX-OK BORDER THIS MORNING WILL MOVE INTO SOUTHERN ILLINOIS
LATE TONIGHT. THIS LOW IS BEING MAINTAINED BY A SHORTWAVE TROUGH
ALMOST CUT OFF FROM THE MAIN JET STREAM FLOW WELL TO THE NORTH
ACROSS THE NORTHERN UNITED STATES.
THICKENING HIGH AND MID LEVEL CLOUDS EARLY THIS MORNING ARE BEING
PRODUCED BY PACIFIC AND NOW GULF MOISTURE BEING ADVECTED OUT AHEAD
OF THE SHORTWAVE DISTURBANCE. DRY LOW LEVELS OF THE ATMOSPHERE PLUS
AND A PERSISTENT MID TO UPPER LEVEL RIDGE ACROSS THE SOUTHERN
APPALACHIANS ARE HELPING ERODE PRECIPITATION THAT IS TRYING TO
STREAM EAST-SOUTHEAST FROM KENTUCKY AND TENNESSEE. RADAR COMPOSITES
SHOW A NARROW BUT IMPRESSIVE AREA OF MODERATE TO HEAVY RAINFALL
ACROSS NORTHERN GEORGIA THAT LOOKS TO BE MOVING IN THE GENERAL
DIRECTION OF THE SANTEE RIVER BASIN. IF ANY OF THIS PRECIPITATION
SURVIVES OUR DRY AIR...IT WOULD REACH WILLIAMSBURG AND GEORGETOWN
COUNTIES BETWEEN 6-9 AM. THE 04Z HRRR APPEARS TO HAVE A GOOD HANDLE
ON THIS PRECIPITATION AND SHOWS ONLY A COUPLE HUNDREDTHS OF AN INCH
SCATTERED ALONG THE SANTEE RIVER LATER THIS MORNING.
PARTLY TO MOSTLY CLOUDY SKIES WILL CONTINUE THROUGH THE MORNING AND
AFTERNOON HOURS. HIGH SUN ANGLES (SAME AS IN MID AUGUST) WILL CUT
THROUGH THE CLOUDS AND PUSH TEMPERATURES INTO THE LOWER TO MID 70S
AWAY FROM THE BEACHES.
AN INTERESTING SITUATION WILL DEVELOP ACROSS CENTRAL SOUTH CAROLINA
LATE THIS AFTERNOON AS THE GFS AND ECMWF SHOW A NARROW ZONE OF
RATHER IMPRESSIVE ISENTROPIC LIFT DEVELOPING ALONG THE 305-310K
THETA SURFACES...APPROXIMATELY 12000-16000 FT AGL. THIS IS MUCH
HIGHER UP THAN WHERE I TYPICALLY ANALYZE ISENTROPIC LIFT BUT APPEARS
TO BE WHAT THE MODELS ARE LATCHING ONTO FOR THE DEVELOPMENT OF RAIN
THAT MAY AFFECT THE SC PEE DEE REGION JUST BEFORE SUNSET. I HAVE
INCREASED POPS TO 30-40 PERCENT MAINLY BETWEEN 5-9 PM...WITH MODELS
INDICATING THAT AGAIN THE RAIN WILL DRY UP AS IT TRIES TO MOVE EAST
TOWARD THE COAST. PERHAPS EVEN MORE INTERESTING IS THE POTENTIAL FOR
SMALL ELEVATED INSTABILITY ORIGINATING FROM VERY HIGH ALOFT...
500-550 MB. IT IS QUITE RARE FOR CONVECTION TO DEVELOP FROM SUCH A
HIGH BASE IN THIS PART OF THE COUNTRY...BUT THIS COULD ADD A LITTLE
CONVECTIVE CHARACTER TO WHAT MAY BE AN OTHERWISE STRATIFORM RAIN
EVENT. EVEN THE MOST AGGRESSIVE MODEL SHOWS CAPE LESS THAN 100 J/KG
SO WE`RE NOT TALKING ABOUT SEVERE WEATHER BY ANY STRETCH.
PRECIPITATION SHOULD DIMINISH IN COVERAGE DURING THE LATE EVENING
HOURS...BUT WITH PLENTY OF CLOUDS REMAINING OVERNIGHT. LOWS SHOULD
FALL TO 50-55...WARMEST ALONG THE SC COAST WITH THE ONSHORE WIND AND
ALSO BACK UNDER THE CLOUDS ACROSS THE PEE DEE REGION.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...SURFACE AND MID LEVEL RIDGE AXIS SHIFT
OFFSHORE EARLY IN THE PERIOD ALLOWING DEEP RETURN FLOW. PLENTY OF
DEEP MOISTURE IN PLACE WITH 850-500 LAYER RH VALUES GREATER THAN 75%
FOR THE DURATION OF THE PERIOD. ALTHOUGH SIGNIFICANT DYNAMICAL
FEATURES ARE LACKING THE FLOW ALOFT IS DIVERGENT. ADDITIONALLY THERE
ARE LIKELY TO BE WEAK AREAS OF POSITIVE VORTICITY ADVECTION ROTATING
THROUGH SHORTWAVE TROUGH TO THE WEST. TIMING THESE FEATURES 2 AND 3
DAYS OUT IS DIFFICULT AT BEST BUT THESE WOULD CERTAINLY HELP ENHANCE
ANY ONGOING CONVECTION AS THEY MOVE INTO THE AREA. ALTHOUGH
CONVECTIVE PARAMETERS ARE LIMITED LOW LEVEL CONVERGENCE COMBINED
WITH DIURNAL INSTABILITY SHOULD GENERATE SHOWERS. BEST PRECIP
CHANCES APPEAR TO BE EARLY MON AND MON NIGHT WITH ENHANCED
DIVERGENCE ALOFT AND INCREASED DEEP MOISTURE. HIGHS WILL FALL A
LITTLE SHORT OF CLIMO GIVEN INCREASED CLOUD COVER AND RAIN CHANCES.
ABUNDANT MOISTURE WILL KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM SATURDAY...MEDIUM RANGE GUIDANCE CONTINUES TO HAVE
PROBLEMS WITH EVOLUTION OF MID LEVEL PATTERN OVER THE CONUS NEXT
WEEK. HOWEVER SOME NUGGETS OF INFORMATION CAN BE GLEANED FROM THE
CHAOS. EARLY IN THE PERIOD WEAK PATTERN ALOFT AND COASTAL TROUGH
LEAD TO DIURNAL CONVECTION...THOUGH COVERAGE WILL BE LIMITED BY MID
LEVEL DRY AIR. BY THE MIDDLE OF NEXT WEEK THERE WILL BE A SOUTHERN
STREAM SYSTEM CROSSING THE NORTHERN GULF OF MEXICO. AT THE SAME TIME
A SIGNIFICANT COLD FRONT WILL BE DRIVEN ACROSS THE CENTRAL US BY
LONGWAVE MID LEVEL TROUGH. LATE IN THE PERIOD BOTH ECMWF AND GFS
HINT AT SOUTHERN STREAM SHORTWAVE INDUCING A COASTAL LOW OFF THE
SOUTHEAST COAST WHICH IS THEN LIFTED NORTH AHEAD OF THE COLD FRONT.
DESPITE SIMILARITIES BETWEEN THE GFS/ECMWF THERE REMAIN PLENTY OF
MAJOR DIFFERENCES. BOTH MODELS SHOW THE MID LEVEL TROUGH BECOMING
CUTOFF BUT DO SO AT DIFFERENT TIMES AND LOCATIONS. THE GFS IS SLOWER
TO CUTOFF THE 5H TROUGH AND THUS IS FARTHER EAST. GIVEN THE
UNCERTAINTY WILL KEEP POP CAPPED AT CHANCE WITH HIGHEST VALUES
DURING THE DAY. TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...VFR THROUGH THE PERIOD. INCREASING RAIN CHANCES TONIGHT.
HIGH AND MID CLOUDS WILL CONTINUE TO THICKEN ACROSS THE AREA. LATEST
HIGH-RES MODELS INDICATE MODERATE TO HEAVY RAIN ACROSS S TN AND N GA
MAY MAKE A RUN TOWARD THE FLORENCE AIRPORT 10-13Z. I WILL MONITOR
CLOSELY TO SEE IF RAIN NEEDS TO BE ADDED TO OUR TAF FORECAST.
OTHERWISE RAIN CHANCES INCREASE FOR THE INLAND TERMINALS TOWARDS THE
EVENING HOURS...AND THEN FOR THE COASTAL TERMINALS INTO THE
OVERNIGHT HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER SATURDAY NIGHT THROUGH TUESDAY
AS AN OVERRUNNING SCENARIO GIVES US MOSTLY CLOUDY CONDITIONS THROUGH
WEDNESDAY WITH PERIODS OF RAIN AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SATURDAY...STRONG HIGH PRESSURE OVER NEW ENGLAND WILL
MOVE EAST AND INTO THE NORTH ATLANTIC LATER TODAY. THE HIGH WILL
CONTINUE TO RIDGE SOUTHWARD TOWARD THE CAROLINAS WITH NORTHEAST TO
EAST WIND CONTINUING. WIND SPEEDS SHOULD REMAIN A VERY CONSISTENT
10-15 KNOTS THROUGH TONIGHT...WHICH GIVEN THE LONG FETCH
ORIGINATING FROM NEWFOUNDLAND IS ENOUGH TO MAINTAIN A NEARLY
STEADY SEA STATE OF 3-4 FT NORTH OF CAPE FEAR AND EAST OF
GEORGETOWN...WITH 2-4 FT SEAS ELSEWHERE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...LIGHT EASTERLY FLOW AT THE START OF THE PERIOD
QUICKLY BECOMES SOUTHEAST AS SURFACE RIDGE AXIS SHIFTS EAST OF THE
WATERS. ONLY SUBTLE CHANGES TO THE GRADIENT EXPECTED DURING THE
PERIOD WITH SEABREEZE DEVELOPMENT ENHANCING SPEEDS SLIGHTLY. SPEEDS
WILL REMAIN IN THE 10 TO 15 KT RANGE WITH SEAS RUNNING 3 TO 5 FT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...SOUTHERLY FLOW CONTINUES THROUGH THE PERIOD
WITH SURFACE HIGH CENTERED NORTHEAST OF THE WATERS BEING THE
DOMINANT FEATURE. GRADIENT REMAINS ON THE WEAK SIDE WITH SPEEDS
STRUGGLING TO REACH 15 KT EVEN WITH THE HELP OF SEABREEZE
ENHANCEMENT. SEAS WILL RUN 3 TO 4 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
130 AM EDT SAT APR 27 2013
.SYNOPSIS...
CLEAR WEATHER WILL PREVAIL INTO SATURDAY AS HIGH PRESSURE PASSES
NORTH OF THE REGION. SEVERAL DISTURBANCES MOVING EAST ACROSS THE
GULF STATES...WILL BRING INCREASING CLOUDS SUNDAY AND A CHANCE OF
RAIN LATE SUNDAY THROUGH MONDAY. A DRYING TREND IS EXPECTED DURING
THE MIDDLE OF NEXT WEEK WITH AN APPROACHING COLD FRONT LATE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 130 AM SATURDAY...MID AND HIGH CLOUDS WILL CONTINUE TO PUSH
INTO THE AREA OVERNIGHT. WHILE THE LEADING EDGE OF THE CLOUD COVER
WILL PARTIALLY ERODE THE SKY SHOULD BECOME OVERCAST ACROSS THE SC
PEE DEE REGION BY 4 AM. LATEST HRRR AND GFS SHOW LIGHT PRECIP MAKING
IT AS FAR EAST AS FLORENCE AND KINGSTREE BETWEEN 6-9 AM SATURDAY
MORNING. LOOKING AT UPSTREAM RADARS THERE CERTAINLY IS QUITE A SWATH
OF MODERATE TO HEAVY RAINFALL ACROSS SOUTHERN TENNESSEE AND ENTERING
NORTH GEORGIA...MAKING A BEELINE FOR THIS REGION. MY NEXT UPDATE AT
3 AM WILL BETTER ADDRESS THE POTENTIAL FOR MEASURABLE RAIN ACROSS
THE AREA. OTHERWISE THE ONLY SUBSTANTIAL CHANGE TO THE FORECAST WAS
TO RAISE FORECAST LOW TEMPERATURES BY SEVERAL DEGREES ACROSS THE PEE
DEE REGION WITH THE THICKER CLOUDS EXPECTED TO MOVE IN SHORTLY.
PREVIOUS DISCUSSION FROM 1120 PM FOLLOWS...
EXTRAPOLATION OF THE CURRENT 11-3.9 MICRON SATELLITE IMAGERY LOOPS
INDICATE MAJORITY OF THE OPAQUE MID TO UPPER LEVEL CLOUDS TO REMAIN
NORTH OF THE FA THIS EVENING. DURING THE PRE-DAWN HRS...THIN TO
OPAQUE MID TO UPPER LEVEL CLOUDS WILL FURTHER SPILL OVER THE LOW
AMPLIFIED UPPER RIDGE AND COVERING THE MAJORITY OF THE ILM CWA BY
DAYBREAK. CURRENT MIN TEMP FORECAST BASICALLY ON TARGET...WITH THE
ONLY TWEAKS OF 1 TO 2 DEGREES LOWER TARGETING THE COASTAL ILM NC
COUNTIES. CLOUDINESS OVERSPREADING THE AREA LATER TONIGHT WILL
PREVENT ANY DECENT RADIATIONAL COOLING OVERNIGHT. SFC BASED
INVERSION WILL RESULT IN DECOUPLING WINDS ACROSS INLAND LOCATIONS
WHERE WINDS WILL DROP TO BETWEEN CALM AND NE-E AT 2 MPH. THE
EXCEPTION WILL BE ALONG THE IMMEDIATE COAST...WHERE NE-E WINDS WILL
DROP TO AROUND 5 MPH.
THE TIDE GAGE SITUATED IN THE CAPE FEAR RIVER IN THE VICINITY OF
DOWNTOWN WILMINGTON...IS MODELED TO APPROACH 5.45 FT MLLW AT THE
NEXT HIDE TIDE AROUND MIDNIGHT TONIGHT. THIS REMAINS JUST SHY OF THE
5.5 FT MLLW HEIGHT...WHICH IS THE THRESHOLD FOR MINOR COASTAL
FLOODING ACROSS THOSE USUAL PRONE LOCATIONS. WILL HAVE TO MONITOR
THE HIGH TIDE PROGGED GAGE READINGS FOR TOMORROW NIGHT...WHICH
ARE ALSO MODELED TO BE NEAR MINOR COASTAL FLOODING THRESHOLDS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 315 PM FRIDAY...SHORT WAVE TROUGH CURRENTLY OVER THE CENTRAL
PLAINS WILL DRIFT E OF THE MS VALLEY BY SUNDAY NIGHT. THIS PATTERN
WILL RESULT IN AN INCREASE IN CLOUD COVER SATURDAY THROUGH
SUNDAY...AND RAINFALL INCREASING...ESPECIALLY TOWARD THE LATTER
PORTIONS OF THE PERIOD. FOR SATURDAY...THINK THE BEST...ALBEIT
SLIGHT CHANCES...FOR SHOWERS WILL BE ACROSS THE PEE DEE. HOWEVER BY
SUNDAY EXPECT EQUAL CHANCES FOR SHOWERS FOR MOST LOCATIONS WITHIN
THE FORECAST AREA AS A DIFLUENT PATTERN ALOFT TAKES HOLD WITH THE
PASSAGE OF THE MID/UPPER RIDGE AXIS AND APPROACH OF THE
AFOREMENTIONED SHORT WAVE. COULD SEE ISOLATED TSTMS BY SUNDAY
AFTERNOON/EVENING...BUT CONVECTIVE PARAMETERS ARE NOT ALL THAT
IMPRESSIVE AT THIS TIME. QPF MAY APPROACH 1 INCH ACROSS THE PEE DEE
ZONES THEN GRADUATED LOWER TO A THIRD TO HALF OF AN INCH FOR THE
REMAINDER OF THE AREA. OTHERWISE...MAX TEMPERATURES ARE EXPECTED TO
BE A FEW CATEGORIES BELOW NORMAL LACKING ANY SIGNIFICANT WARM AIR
ADVECTION AND INCREASED CLOUD COVER. MIN TEMPERATURES WILL A NOTCH
BELOW CLIMO SATURDAY NIGHT...THEN BE RIGHT AROUND NORMAL FOR SUNDAY
NIGHT.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 PM FRIDAY...RETURN FLOW AROUND HIGH PRESSURE OFF THE COAST
WILL CONTINUE TO VEER TO THE S-SW AS SURFACE LOW LIFTS OFF TO THE
GREAT LAKES. SHORTWAVE FOLLOWS SUIT LIFTING NORTHEAST THROUGH THE
OHIO VALLEY AND WEAKENING LATE MONDAY NIGHT INTO TUESDAY. BEST
SHORTWAVE ENERGY WILL MOVE THROUGH ON MONDAY BUT WARM MOIST
SOUTHERLY RETURN FLOW WILL PERSIST THROUGH MONDAY INTO TUESDAY. ONCE
SHORTWAVE TROUGH AXIS SHIFTS OFF THE COAST ON TUES...SHOULD SEE SOME
DRYING AND SUBSIDENCE ON BACK END THROUGH MID WEEK. THIS MAY BE
SHORT-LIVED AS A LOW DEVELOPS ALONG THE GULF COAST AND MAY SEE
MOISTURE RETURN WED INTO THURS. GFS TRACKS LOW ACROSS THE CAROLINAS
THURS NIGHT INTO FRIDAY BUT LIFTS IT OFF TO THE NORTHEAST BY LATE
FRIDAY. THE ECMWF IS MUCH SLOWER WITH THE MOVEMENT OF LOW PRESSURE
MOVING UP FROM THE GULF AND SHOWS THE LOW STILL OVER THE CAROLINAS
ON SUNDAY. WITH SO MUCH UNCERTAINTY...BASICALLY KEPT FORECAST AS IS
WITH A CONSIDERABLE AMOUNT OF CLOUDS AND CHC OF SHWRS/TSTMS THURS
AND FRI.
TEMPS SHOULD RUN BELOW CLIMO MON AND TUES WITH GREATER AMT OF CLOUDS
AND PCP AROUND AND KEEPING TEMPS CLOSER TO CLIMO THROUGH THE
REMAINDER OF THE WEEK FOR NOW.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...VFR THROUGH THE PERIOD. INCREASING RAIN CHANCES TONIGHT.
HIGH AND MID CLOUDS WILL CONTINUE TO THICKEN ACROSS THE AREA. LATEST
HIGH-RES MODELS INDICATE MODERATE TO HEAVY RAIN ACROSS S TN AND N GA
MAY MAKE A RUN TOWARD THE FLORENCE AIRPORT 10-13Z. I WILL MONITOR
CLOSELY TO SEE IF RAIN NEEDS TO BE ADDED TO OUR TAF FORECAST.
OTHERWISE RAIN CHANCES INCREASE FOR THE INLAND TERMINALS TOWARDS THE
EVENING HOURS...AND THEN FOR THE COASTAL TERMINALS INTO THE
OVERNIGHT HOURS.
EXTENDED OUTLOOK...UNSETTLED WEATHER SATURDAY NIGHT THROUGH TUESDAY
AS AN OVERRUNNING SCENARIO GIVES US MOSTLY CLOUDY CONDITIONS THROUGH
WEDNESDAY WITH PERIODS OF RAIN AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM SATURDAY...SUSTAINED WINDS ARE AT OR BELOW 15 KNOTS
ACROSS ALL OF THE COASTAL WATERS AND OUT AT THE FRYING PAN SHOALS
BUOY. LATEST HRRR AND RUC NEAR-TERM MODELS HAVE CAPTURED THIS
IMPROVING TREND QUITE WELL AND WERE USED TO MODIFY OUR WIND FORECAST
FOR THE NEXT 9 HOURS. WITH SEAS NOW ONLY 4.9 FEET AT THE FRYING PAN
SHOALS BUOY IT IS UNLIKELY SUBSTANTIAL AREAS OF 5 FOOT SEAS ARE
BEING EXPERIENCED WITHIN 20 MILES OF SHORE. WITH THE MAJORITY OF THE
WAVE ENERGY IN THE LONGER END OF THE ENERGY SPECTRUM...8 TO 11
SECONDS...THE EXERCISE CAUTION HEADLINE HAS BEEN DROPPED WITH THIS
UPDATE.
WIND OBS REPORTED FROM BUOY 41037...THE "OFFSHORE" WRIGHTSVILLE
BEACH BUOY...ARE ABOUT 160% OF THE ACTUAL SUSTAINED WIND AND GUSTS.
THIS HAS BEEN THE CASE FOR AT LEAST THE PAST MONTH. PLEASE USE WITH
CAUTION EVEN AFTER MAKING CORRECTIONS.
SHORT TERM/SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 315 PM FRIDAY...EASTERLY FLOW WILL PREVAIL THROUGH SATURDAY
THEN VEER TO THE SOUTH BY SUNDAY NIGHT AS HIGH PRESSURE MIGRATES OFF
THE MID-ATLANTIC COAST. SPEEDS WILL REMAIN AROUND 10 KT OR AT MOST
IN THE 10-15 KT RANGE THROUGH THE SHORT TERM. WAVES WILL GENERALLY
AVERAGE 3 TO 4 FT...WITH THE HIGHEST VALUES ACROSS THE OUTER COASTAL
WATERS.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 315 PM FRIDAY...SHOULD SEE LIGHT RETURN FLOW BETWEEN HIGH
PRESSURE OFF SHORE AND LOW PRESSURE TRACKING NORTHEAST UP INTO THE
GREAT LAKES MON INTO TUESDAY. EXPECT WINDS OUT OF THE S-SE UP TO 15
KTS. ON SHORE FLOW SHOULD KEEP SEAS AROUND 3 TO 4 FT MON AND
TUESDAY. WINDS SHOULD BECOME MORE EASTERLY THROUGH WEDNESDAY AS LOW
PRESSURE BEGINS TO DEVELOP OVER THE GULF COAST. SOME UNCERTAINTY
EXISTS AS TO HOW THIS LOW WILL AFFECT THE COASTAL WATERS. THEREFORE
LOWER CONFIDENCE FORECAST FROM WEDNESDAY ON.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SRP
NEAR TERM...DCH/TRA
SHORT TERM...SRP
LONG TERM...RGZ
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
753 PM EDT SUN APR 28 2013
.SYNOPSIS...
LOW PRESSURE ALONG THE INDIANA AND OHIO BORDER WILL DRIFT NORTH
AND GRADUALLY DISSIPATE BY MONDAY MORNING. HIGH PRESSURE WILL
BUILD ACROSS THE AREA LATE MONDAY THROUGH AT LEAST MIDWEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST UPDATE IS TO MENTION A CHANCE OF THUNDER IN MORROW...KNOX
AND HOLMES COUNTY THIS EVENING.
THE EARLY EVENING UPDATE WAS TO REFINE TEMPERATURES THROUGH
MIDNIGHT...A LITTLE COOLER AT FIRST WHERE IT HAS BEEN
RAINING...THEN A COUPLE OF DEGREES WARMER THAN THE EARLIER
FORECAST SINCE HIGH DEWPOINTS AND WARMER AIR ARE MOVING IN FROM
THE SOUTH THIS EVENING.
EMPHASIZED SHOWERS MAINLY FOR THIS EVENING FOR NORTHWEST OHIO AND
BEFORE MIDNIGHT NORTH CENTRAL OHIO. DID NOT TRY TO TIME THE
SHOWERS AS MUCH NE OH/NW PA ALTHOUGH THE SHOWERS WILL ALMOST
CERTAINLY TAPER OFF SOMEWHAT DURING THE EARLY MORNING HOURS.
EARLIER DISCUSSION...
KIND OF A TRICKY FORECAST FOR TONIGHT. PRECIP COVERAGE CONTINUES
TO DISSIPATE. COMMA HEAD FROM THE UPPER LOW CLEARLY VISIBLE ON THE
RADAR. THE MAIN AREA OF RAIN IS NOW MOVING OUT OVER LAKE ERIE BUT
NEW DEVELOPMENT CONTINUES TO THE SOUTH. THIS SECOND WAVE OF PRECIP
WILL BE SCATTERED IN NATURE THIS EVENING. ALL OF THE NEW GUIDANCE
INCLUDING THE LATEST HRRR SHOW ABOUT 50 PERCENT COVERAGE MOST OF
THE EVENING. THE SHOWERS WILL BE CELLULAR IN NATURE WHICH WOULD
LEAD ME TO BELIEVE THERE COULD BE SOME ISOLATED THUNDER. JUST
CAN`T SEE THAT HAPPENING THOUGH GIVEN THE THICK CLOUDS AND LACK OF
INSTABILITY OVER THE AREA. WILL REMOVE THE EARLIER MENTION OF
THUNDER FROM THE FORECAST. BY 06Z ANY REMAINING PRECIP SHOULD BE
OVER THE EAST HALF OF THE AREA. CLOUDS EXTEND WEST ACROSS THE
GREAT LAKES AND SEE NO CHANCE OF CLEARING TONIGHT. SOME OF THE
GUIDANCE IS SUGGESTING SOME FOG DEVELOPMENT OVERNIGHT SO THE
EVENING CREW WILL HAVE TO WATCH THAT. USED A BLEND OF GUIDANCE
TEMPS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS IN FAIR AGREEMENT DURING THE PERIOD AND SHOW AN UPPER
TROUGH ROTATING ACROSS THE REGION LATE TONIGHT AND MONDAY. THIS
FEATURE SHOULD KICK OFF A FEW MORE SHOWERS WITH BEST CHANCES BEING
IN THE EAST. SYNOPTIC SCALE SUBSIDENCE BEHIND THE WAVE SHOULD
BRING AN END TO THE PRECIP MONDAY EVENING. THE REMAINDER OF THE
PERIOD SHOULD THEN BE DRY AS THE LOCAL AREA REMAINS BETWEEN WEAK
SYSTEMS. WEAK RIDING WILL TRY TO OCCUR DURING THE PERIOD. THIS MAY
BE ENOUGH TO BREAK UP THE CLOUDS SOME BUT NOT ENOUGH TO CLEAR
THINGS OUT. THE AREA WILL SEE A PROLONGED PERIOD OF S TO SW FLOW
WHICH WILL MODERATE TEMPS. HIGHS COULD GET TO 70 TOMORROW IN THE
WEST AND ACROSS MOST OF THE AREA ON TUESDAY AND WEDNESDAY. LAKE
BREEZES APPEAR LIKELY IN THE AFTERNOON SO THE IMMEDIATE LAKESHORE
AREAS WILL BE COOLER. HAVE USED A BLEND OF GUIDANCE MOST OF THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE APPEARS IT WILL BECOME THE DOMINATING WEATHER FEATURE
ACROSS THE AREA FOR A GOOD PART OF THE EXTENDED PERIODS. UPPER LEVEL
RIDGE BUILDS OVER THE EASTERN UNITED STATES AND SETS UP A SURFACE
HIGH OVER THE EASTERN SEABOARD. THIS FEATURE WILL KEEP A SOUTHERLY
COMPONENT TO THE WIND ALLOWING FOR WARM AIR ADVECTION TO TAKE PLACE
INTO FRIDAY. FRONTAL BOUNDARY WILL STALL WEST OF THE REGION WILL
MAKE SLOW PROGRESS INTO THE AREA ON SATURDAY. THIS FEATURE WILL
BRING THE NEXT CHANCE OF RAIN SATURDAY INTO SATURDAY NIGHT. THERE IS
THE POSSIBILITY THAT THE FRONT COULD LINGER INTO THE AREA ON SUNDAY
WITH A CHANCE OF SHOWERS. MADE A FEW ADJUSTMENTS TO TEMPERATURES
BUT NOTHING MAJOR AS MODELS ARE FAIRLY CONSISTENT WITH YESTERDAYS
RUN.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
LOW CONFIDENCE IN THE VERY SHORT TERM WITH VARIABLE CONDITIONS FOR
THE NEXT SEVERAL HOURS. OTHERWISE ALL INDICATIONS ARE THAT
CONDITIONS WILL DETERIORATE FOR THE OVERNIGHT.
SHOWERS WILL BE AROUND MAINLY THROUGH MIDNIGHT...EXCEPT EARLY
MORNING HOURS ACROSS NE OH/NW PA. THUNDER MAY BE POSSIBLE AT MFD
IN THE NEXT 1 TO 2 HOURS. THIS EVENING MVFR WITH SOME VFR AND
ISOLATED IFR MIXED IN. FOR THE OVERNIGHT TOL WILL MOST LIKELY BE
IFR THROUGH THE NIGHT AS FOG DEVELOPS OVER NW OH. FDY WILL BE ON
THE EDGE. ELSEWHERE HIRES MODELS WANT TO BRING IN LOW END MVFR AND
IFR CIGS OVERNIGHT AND THIS SEEMS REASONABLE. SURFACE LOW IS OVER
WEST-CENTRAL OHIO...BUT WILL DISSIPATE AS IT MOVES NORTHEAST.
IMPROVEMENT MONDAY MORNING AS RIDGE BUILDS IN. MAY STILL HAVE SOME
LINGERING SHOWERS ACROSS THE EAST.
.OUTLOOK...NON-VFR POSSIBLE IN BR THURSDAY AND/OR FRIDAY MORNING.
&&
.MARINE...
ONCE THIS STORM SYSTEM MOVES NORTHEAST OF THE AREA TONIGHT AND
MONDAY MORNING...LOOKING AT RATHER QUIET WEATHER ON THE LAKE. NOT
ANTICIPATING ANY STRONG STORM SYSTEMS TO SUPPORT STRONGER WINDS.
THEREFORE...WILL KEEP WINDS LIGHT AND WAVES ON THE LIGHT SIDE
THROUGH THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KOSARIK/KUBINA
NEAR TERM...KOSARIK/KUBINA
SHORT TERM...KUBINA
LONG TERM...LOMBARDY
AVIATION...OUDEMAN
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
729 PM EDT SUN APR 28 2013
.SYNOPSIS...
LOW PRESSURE ALONG THE INDIANA AND OHIO BORDER WILL DRIFT NORTH
AND GRADUALLY DISSIPATE BY MONDAY MORNING. HIGH PRESSURE WILL
BUILD ACROSS THE AREA LATE MONDAY THROUGH AT LEAST MIDWEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
LATEST UPDATE IS TO MENTION A CHANCE OF THUNDER IN MORROW...KNOX
AND HOLMES COUNTY THIS EVENING.
THE EARLY EVENING UPDATE WAS TO REFINE TEMPERATURES THROUGH
MIDNIGHT...A LITTLE COOLER AT FIRST WHERE IT HAS BEEN
RAINING...THEN A COUPLE OF DEGREES WARMER THAN THE EARLIER
FORECAST SINCE HIGH DEWPOINTS AND WARMER AIR ARE MOVING IN FROM
THE SOUTH THIS EVENING.
EMPHASIZED SHOWERS MAINLY FOR THIS EVENING FOR NORTHWEST OHIO AND
BEFORE MIDNIGHT NORTH CENTRAL OHIO. DID NOT TRY TO TIME THE
SHOWERS AS MUCH NE OH/NW PA ALTHOUGH THE SHOWERS WILL ALMOST
CERTAINLY TAPER OFF SOMEWHAT DURING THE EARLY MORNING HOURS.
EARLIER DISCUSSION...
KIND OF A TRICKY FORECAST FOR TONIGHT. PRECIP COVERAGE CONTINUES
TO DISSIPATE. COMMA HEAD FROM THE UPPER LOW CLEARLY VISIBLE ON THE
RADAR. THE MAIN AREA OF RAIN IS NOW MOVING OUT OVER LAKE ERIE BUT
NEW DEVELOPMENT CONTINUES TO THE SOUTH. THIS SECOND WAVE OF PRECIP
WILL BE SCATTERED IN NATURE THIS EVENING. ALL OF THE NEW GUIDANCE
INCLUDING THE LATEST HRRR SHOW ABOUT 50 PERCENT COVERAGE MOST OF
THE EVENING. THE SHOWERS WILL BE CELLULAR IN NATURE WHICH WOULD
LEAD ME TO BELIEVE THERE COULD BE SOME ISOLATED THUNDER. JUST
CAN`T SEE THAT HAPPENING THOUGH GIVEN THE THICK CLOUDS AND LACK OF
INSTABILITY OVER THE AREA. WILL REMOVE THE EARLIER MENTION OF
THUNDER FROM THE FORECAST. BY 06Z ANY REMAINING PRECIP SHOULD BE
OVER THE EAST HALF OF THE AREA. CLOUDS EXTEND WEST ACROSS THE
GREAT LAKES AND SEE NO CHANCE OF CLEARING TONIGHT. SOME OF THE
GUIDANCE IS SUGGESTING SOME FOG DEVELOPMENT OVERNIGHT SO THE
EVENING CREW WILL HAVE TO WATCH THAT. USED A BLEND OF GUIDANCE
TEMPS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
MODELS IN FAIR AGREEMENT DURING THE PERIOD AND SHOW AN UPPER
TROUGH ROTATING ACROSS THE REGION LATE TONIGHT AND MONDAY. THIS
FEATURE SHOULD KICK OFF A FEW MORE SHOWERS WITH BEST CHANCES BEING
IN THE EAST. SYNOPTIC SCALE SUBSIDENCE BEHIND THE WAVE SHOULD
BRING AN END TO THE PRECIP MONDAY EVENING. THE REMAINDER OF THE
PERIOD SHOULD THEN BE DRY AS THE LOCAL AREA REMAINS BETWEEN WEAK
SYSTEMS. WEAK RIDING WILL TRY TO OCCUR DURING THE PERIOD. THIS MAY
BE ENOUGH TO BREAK UP THE CLOUDS SOME BUT NOT ENOUGH TO CLEAR
THINGS OUT. THE AREA WILL SEE A PROLONGED PERIOD OF S TO SW FLOW
WHICH WILL MODERATE TEMPS. HIGHS COULD GET TO 70 TOMORROW IN THE
WEST AND ACROSS MOST OF THE AREA ON TUESDAY AND WEDNESDAY. LAKE
BREEZES APPEAR LIKELY IN THE AFTERNOON SO THE IMMEDIATE LAKESHORE
AREAS WILL BE COOLER. HAVE USED A BLEND OF GUIDANCE MOST OF THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
HIGH PRESSURE APPEARS IT WILL BECOME THE DOMINATING WEATHER FEATURE
ACROSS THE AREA FOR A GOOD PART OF THE EXTENDED PERIODS. UPPER LEVEL
RIDGE BUILDS OVER THE EASTERN UNITED STATES AND SETS UP A SURFACE
HIGH OVER THE EASTERN SEABOARD. THIS FEATURE WILL KEEP A SOUTHERLY
COMPONENT TO THE WIND ALLOWING FOR WARM AIR ADVECTION TO TAKE PLACE
INTO FRIDAY. FRONTAL BOUNDARY WILL STALL WEST OF THE REGION WILL
MAKE SLOW PROGRESS INTO THE AREA ON SATURDAY. THIS FEATURE WILL
BRING THE NEXT CHANCE OF RAIN SATURDAY INTO SATURDAY NIGHT. THERE IS
THE POSSIBILITY THAT THE FRONT COULD LINGER INTO THE AREA ON SUNDAY
WITH A CHANCE OF SHOWERS. MADE A FEW ADJUSTMENTS TO TEMPERATURES
BUT NOTHING MAJOR AS MODELS ARE FAIRLY CONSISTENT WITH YESTERDAYS
RUN.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
RAIN CONTINUES TO ROTATE THROUGH THE AREA THIS AFTERNOON WITH THE
MAIN BAND LIFTING NORTHEAST ACROSS NORTHEAST OHIO AND NORTHWEST
PENNSYLVANIA. SECONDARY AREA OF CONVECTIVE SHOWERS CONTINUES TO
DEVELOP OVER SOUTH CENTRAL OHIO AND THIS ACTIVITY WILL LIFT
NORTHEAST. ANTICIPATE THE ONLY PLACE WE MAY HEAR THUNDER IS AT
AKRON CANTON AND YOUNGSTOWN. WILL LEAVE MENTION OF THUNDER OUT OF
THE FORECAST ELSEWHERE. PRECIPITATION IS JUST ABOUT DONE IN
NORTHWEST OHIO FOR THE WIDESPREAD RAIN. MAY SEE SOME SCATTERED
SHOWER ACTIVITY THROUGH THE REST OF THE AFTERNOON.
CEILINGS WILL REMAIN FAIRLY LOW THROUGH MUCH OF THE PERIOD BUT
WILL SEE SOME IMPROVEMENT TOWARD THE END OF THE FORECAST PERIOD.
VISIBILITIES COULD BE REDUCED OVERNIGHT BY FOG DEVELOPMENT DUE TO
MOIST GROUND. NOT EXPECTING ANY WORSE THAN A HALF MILE AT ANY
LOCATION.
.OUTLOOK...NON-VFR POSSIBLE IN FOG THURSDAY MORNING.
&&
.MARINE...
ONCE THIS STORM SYSTEM MOVES NORTHEAST OF THE AREA TONIGHT AND
MONDAY MORNING...LOOKING AT RATHER QUIET WEATHER ON THE LAKE. NOT
ANTICIPATING ANY STRONG STORM SYSTEMS TO SUPPORT STRONGER WINDS.
THEREFORE...WILL KEEP WINDS LIGHT AND WAVES ON THE LIGHT SIDE
THROUGH THE PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KOSARIK/KUBINA
NEAR TERM...KOSARIK/KUBINA
SHORT TERM...KUBINA
LONG TERM...LOMBARDY
AVIATION...LOMBARDY
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
201 PM EDT SAT APR 27 2013
.SYNOPSIS...
AN INCREASINGLY MOIST WEDGE OF COOLER AIR WILL OVERSPREAD THE REGION
THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY
ALONG A STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE
COOL AIR WEDGE WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK. OUR
WEATHER PATTERN WILL LIKELY REMAIN UNSETTLED THROUGH NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM...I WILL UPDATE THE FORECAST TO REFINE POPS TO RADAR
TRENDS. BASED ON THE LATEST TRENDS...LIGHT TO MODERATE RAIN SHOWERS
SHOULD SPREAD ACROSS THE CLT METRO AREA OVER THE NEXT HOUR OR TWO.
TEMPERATURES ACROSS THE REGION THIS AFTERNOON WILL REMAIN NEARLY
STEADY.
AS OF 1115 AM...LATEST RADAR TRENDS HAVE INDICATED AN INCREASING
TREND IN RAINFALL RATES ACROSS THE SOUTHERN NC MTNS SE ACROSS THE
SAVANNAH RIVER VALLEY. I WILL INCREASE POPS OVER THE AREA THROUGH
MID DAY. THE REST OF THE CWA HAS MAINLY EXPERIENCED SPRINKLES TO
LIGHT RAIN SHOWERS. THIS TREND MAY CONTINUE OVER THE NEXT COUPLE OF
HOURS. HOWEVER...NEAR TERM MODELS REMAIN IN AGREEMENT WITH SPREADING
COVERAGE EAST ACROSS THE MTNS THIS AFTERNOON WITH THE APPROACH AND
PASSAGE OF A MID LEVEL S/W. I WILL TIME CATE POPS ACROSS THE MTNS
AND ADJACENT FOOTHILLS THIS AFTERNOON. I WILL ALSO COOL TEMPS ACROSS
THE MTNS A COUPLE OF CLICKS...PIEDMONT AREAS APPEARS ON TRACK.
I HAVE ALSO UPDATED THE FORECAST THROUGH SUNDAY. THE MAIN CHANGES
INCLUDE INCREASING POPS AND INDICATING HIGHER QPF OVER UPSLOPE AREAS.
630 AM UPDATE...500MB VORT MAX NOW PASSING THROUGH THE AREA AND
SPARKING A FEW ADDITIONAL SHOWERS OVER THE NW NC PIEDMONT...WHILE
MOST OF THE ACTIVITY REMAINS OVER SW HALF OF CWFA. MADE SOME MORE
ADJUSTMENTS TO POPS INCLUDING SLIGHT EASTWARD EXPANSION TO ACCOUNT
FOR THE PIEDMONT SHOWERS...WHICH LOOK VERY LIGHT ON RADAR AND ARE
NOT LIKELY TO PRODUCE SIGNIFICANT ACCUMS OVER THE NEXT HOUR OR SO.
430 AM UPDATE...ADJUSTED POPS THROUGH DAYBREAK. 06Z NAM DOES NOT
SEEM TO HAVE A GREAT HANDLE ON THE ONGOING PRECIP AROUND THE
REGION...NOT SHOWING ANY ACCUMS FROM THE ACTIVITY IN THE SAVANNAH
RIVER VALLEY. IT DOES CONTINUE TO SUPPORT THE INCREASING POPS NEAR
THE TENN BORDER AFTER SUNRISE. 06Z HRRR SHOWS SOME OF THE CURRENT
ACTIVITY MOVING EAST THEN BRINGS A COUPLE OF WAVES OF SHOWERS ACROSS
BY LATE MORNING. MADE ADJUSTMENTS TO PREVIOUS TREND MOSTLY BASED ON
RADAR MAINLY INTERPRETING THE NEW GUIDANCE AS A CONFIDENCE BOOST.
AS OF EARLY SAT MORNING...SFC HIGH OVER NE CONUS SEEN ON CURRENT SFC
ANALYSIS SITS IN A FAVORABLE POSITION TO ALLOW DEVELOPMENT OF CAD
ACROSS OUR REGION DURING THE NEAR TERM PERIOD. LLVL WINDS ABOVE THE
BOUNDARY LAYER ARE ALREADY SOUTHERLY. THROUGH THE DAY TODAY MIDLEVEL
RIDGE SHIFTS SLIGHTLY EASTWARD AS CLOSED UPPER LOW GROWS OVER THE MID
MISSISSIPPI VALLEY. THE EFFECT WILL BE TO STRENGTHEN THE FLOW OVER
THE CAD WEDGE LEADING TO A SOMEWHAT STEADY INCREASE IN ISENTROPIC
LIFT AND DEEP MOISTURE ADVECTION. MEANWHILE...EXTRA SUPPORT FOR
PRECIP DEVELOPMENT WILL COME FROM VORT MAXES ROUNDING THE SUBTLE
UPPER RIDGE AHEAD OF THE CLOSED LOW. ONE AREA OF PVA IS EXPECTED TO
SPREAD ITS ASSOCIATED PRECIP INTO THE MTNS AROUND DAYBREAK WHILE A
SECOND...SHOWN ON BOTH GFS AND NAM...WILL MOVE THROUGH THIS
AFTERNOON. THAT FEATURE IS CONCURRENT WITH RIGHT REAR QUAD OF 250MB
JET STREAK AND ASSOCIATED DIVERGENCE. UPPER SUPPORT WANES SOMEWHAT ON
GFS THIS EVENING...BUT NAM FEATURES MCV/S MOVING IN AT THAT TIME.
THESE ARE PROBABLY RESULTING FROM CONVECTION UPSTREAM...SO NOT
NECESSARILY BITING ON ANY MODELED EFFECTS FROM THOSE. MIDLEVEL
Q-VECTOR CONVERGENCE DOES CONTINUE TO INCREASE AS HEIGHTS FALL OVER
THE TENN VALLEY AHEAD OF THE UPPER LOW AND AS THE WARM ADVECTION
RAMPS UP.
HAVE NOT MADE MUCH CHANGE TO POP TRENDS WHICH GENERALLY SPREAD WEST
TO EAST DURING THE PERIOD...WITH CATEGORICAL VALUES APPROPRIATE OVER
THE NW HALF OF CWA /WHERE UPSLOPING WILL PLAY THE BIGGEST ROLE AND
ALSO FEATURING THE BEST UPPER SUPPORT/. QPF COULD BE CRITICAL FOR
THIS EVENT AS A WHOLE SO GAVE IT SOME EXTRA THOUGHT. GFS IS THE MOST
ROBUST WITH THE ACTIVITY THIS AFTERNOON WHICH MAKES SENSE GIVEN ITS
EVOLUTION OF THE UPPER FORCING...AND FEATURES LOWER QPF FOR EVENING
BUT WITH SOME INCREASE AGAIN TOWARD SUN MORNING AS THE MOISTURE
DEEPENS. GENERALLY THE DETERMINISTIC TOTALS ARE BACKED UP BY THE
ACCUM PROBABILITIES PRODUCED BY THE ENSEMBLE RUN. CHOSE TO USE A
BLEND OF AVAILABLE DETERMINISTIC GUIDANCE BUT WITH A BIAS TOWARD THE
GFS.
TEMPS TODAY WILL BE BELOW NORMAL GIVEN THE CLOUD COVER AND DEVELOPING
WEDGE...BUT IF PRECIP IS DELAYED OR DOES NOT DEVELOP OVER A
WIDESPREAD AREA TEMPS COULD BE SOMEWHAT WARMER WITHOUT THE RAINFALL
TO LOCK IN THE WEDGE EARLY. WENT WITH RAW MODEL BLEND FOR TONIGHT
ASSUMING THE WEDGE WILL BE FULLY ENTRENCHED BY THEN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 240 AM SATURDAY...AS THE UPPER RIDGE AXIS SHIFTS TO THE
COAST...AND DEEP/VERY MOIST SW FLOW BECOMES ESTABLISHED OVER THE
AREA...POPS WILL CONTINUE TO INCREASE THROUGH SUNDAY WITHIN MODESTLY
STRONG WAA/SOUTHERLY UPSLOPE REGIME. WITH THE CENTER OF THE SURFACE
HIGH EXPECTED TO SHIFT OFF THE NEW ENGLAND COAST BY SUNDAY...IN SITU
COLD AIR DAMMING WILL LIKELY BEGIN TO ERODE AROUND THE PERIPHERY OF
THE FORECAST AREA...ESP THE SOUTHERN PIEDMONT AND FAR SOUTHWEST MTN
ZONES. THIS WILL CREATE THE POTENTIAL FOR INCREASED INSTABILITY/
DEEPER CONVECTION/INCREASED RAINFALL RATES BY AFTERNOON. IN FACT...
SUNDAY AFTERNOON THROUGH SUNDAY NIGHT APPEARS TO BE THE MOST LIKELY
PERIOD OF HEAVY RAINFALL IN LIGHT OF THIS TIME OFFERING THE BEST
JUXTAPOSITION OF UPSLOPE FLOW...INSTABILITY/ MOISTURE...AS WELL AS
INCREASING UPPER LEVEL FORCING. THE LATTER COMES ABOUT AS A RESULT
OF A COUPLED JET STRUCTURE THAT MAXIMIZES SUNDAY EVENING. AREAS
ALONG THE SOUTHERN BLUE RIDGE COULD WELL SEE WIDESPREAD RAINFALL
AMOUNTS OF TWO INCHES WITHIN THIS WINDOW OF TIME ALONE. STORM TOTAL
AMOUNTS OF 2.5 TO 4 INCHES APPEAR TO BE A VERY GOOD BET THROUGH
SUNDAY NIGHT...AND CONFIDENCE IS INCREASING THAT WE MAY HAVE LOCALLY
EXCESSIVE RAINFALL CONCERNS ALONG OUR SOUTHERN BLUE RIDGE COUNTIES.
NEVERTHELESS...I STILL THINK WE ARE AROUND 48 HOURS AWAY FROM SEEING
ANY HYDRO CONCERNS...AND I WOULD LIKE TO SEE HOW TODAY/S RAINFALL
SITUATION UNFOLDS BEFORE HOISTING A WATCH...SO HAVE OPTED TO PUNT TO
THE DAY SHIFT.
BY MONDAY...THE BEST UPPER FORCING AND DEEP MOISTURE WILL SHUNT EAST
OF THE AREA. HOWEVER...SOUTHERLY FLOW WILL PERSIST IN THE LOWER
LEVELS...SUPPORTING AMPLE LOW LEVEL MOISTURE. IN FACT...WITH THE AIR
MASS DRYING SOMEWHAT ALOFT...WE MAY SEE MORE SUN/INSTABILITY MONDAY
AFTERNOON. WITH THE UPPER TROUGH/SHEAR AXIS LINGERING OVER THE
AREA...SOLID CHANCE/LOW LIKELY POPS ARE WARRANTED INTO THE
AFTERNOON. CONVECTION SHOULD BECOME MORE DIURNAL IN NATURE BY THE
END OF THE SHORT TERM PERIOD...SO POPS GRADUALLY TAPER DOWN MONDAY
EVENING.
MAX TEMPERATURES WILL REMAIN BELOW NORMAL SUNDAY UNDER WIDESPREAD
CLOUD COVER AND PRECIPITATION...BUT RETURN TO NEAR CLIMO BY MONDAY.
LOWS WILL BE AT LEAST A CATEGORY ABOVE CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 305 AM SATURDAY...THE MEDIUM RANGE CONTINUES TO APPEAR
UNSETTLED...AS PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW
LEVEL MOISTURE INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES
FOR SHOWERS AND THUNDERSTORMS. THE GLOBAL MODELS CONTINUE TO
ADVERTISE A REASSERTION OF THE EASTERN LOW LEVEL RIDGE AXIS DURING
MID-LATE WEEK. HOWEVER...THEY ARE NOT AS AGGRESSIVE IN DRYING OUT
THE LOWER LEVEL AIR MASS OVER THE CAROLINAS. THERE IS ALSO
CONSIDERABLE UNCERTAINTY REGARDING THE TIMING OF THE NEXT MAJOR
STORM SYSTEM...AS THE PRIMARY GLOBAL MODELS ARE VERY MUCH AT ODDS IN
THEIR HANDLING OF WESTERN CONUS ENERGY LATE IN THE WEEK.
THEREFORE...SLIGHT/CHANCE POPS AND NEAR-CLIMO TEMPS WILL REMAIN IN
THE FORECAST THROUGH THE EXTENDED RANGE PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...THE TERMINAL HAS REMAINED EAST OF THE MAIN BAND OF SHRA
TODAY. HOWEVER...RADAR TRENDS INDICATE THAT LIGHT RAIN WILL REACH
THE TERMINAL AROUND 19Z...POSSIBLY RESULTING IN MVFR VIS BETWEEN
20Z-22Z. -SHRA SHOULD CONTINUE FOR THE REMAINDER OF THE TAF PERIOD.
AFTER SUNSET...MODEL SOUNDINGS AND MOS GUIDANCE INDICATES THAT
MOISTURE WILL INCREASE FROM THE TOP DOWN. BASED ON CONSENSUS OF THE
GUIDANCE...CLOUD BASES MAY REACH MVFR BY 7Z...LOWERING TO JUST ABOVE
010 BY 17Z. MOS INDICATES THE POSSIBILITY OF IFR AFTER SUNRISE...BUT
LEANING ON NAM SOUNDINGS I WILL KEEP IFR OUT OF THE TAF WITH THIS
PACKAGE.
ELSEWHERE...A WIDE BAND OF LIGHT TO MODERATE SHOWERS WILL REMAIN
ACROSS KAVL...KGMU..KGSP THROUGH THIS AFTERNOON. KAND MAY GENERALLY
REMAIN SOUTH OF THE BAND AS KHKY WILL GRADUALLY SEE INCREASING
COVERAGE. CEILINGS WITHIN THE BAND SHOULD REMAIN VFR...WITH ISOLATED
MVFR BASES AT TIMES. RAINFALL SHOULD INITIALLY LIMIT VIS TO MVFR AT
KAVL/KGSP/KGMU THROUGH MID AFTERNOON...THEN EXPECTED TO IMPROVE TO
VFR LATE THIS AFTERNOON. AFTER SUNSET...MODEL SOUNDINGS AND MOS
GUIDANCE INDICATES THAT MOISTURE WILL INCREASE FROM THE TOP DOWN.
BASED ON CONSENSUS OF THE GUIDANCE...CLOUD BASES MAY REACH MVFR
AFTER MIDNIGHT...LOWERING TO IFR AFTER SUNRISE.
OUTLOOK...WIDESPREAD MODERATE TO HEAVY RAIN AND LOW RESTRICTIONS
WILL CONTINUE THROUGH SUNDAY NIGHT. AN UPPER LEVEL WAVE WILL CROSS
THE REGION ON MONDAY...ACCOMPANIED BY SCATTERED THUNDERSTORMS AND
ASSOCIATED RESTRICTIONS. LOW CLOUDS AND FOG WILL THEN BE POSSIBLE
EACH MORNING THROUGH MID WEEK.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 97% MED 79% HIGH 95%
KGSP HIGH 95% HIGH 88% MED 76% HIGH 95%
KAVL HIGH 92% HIGH 86% HIGH 80% HIGH 89%
KHKY HIGH 100% HIGH 92% HIGH 88% HIGH 85%
KGMU HIGH 91% HIGH 87% HIGH 89% MED 78%
KAND HIGH 100% HIGH 83% MED 76% HIGH 93%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...NED/WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...NED
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1122 AM EDT SAT APR 27 2013
.SYNOPSIS...
AN INCREASINGLY MOIST WEDGE OF COOLER AIR WILL OVERSPREAD THE REGION
THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY
ALONG A STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE
COOL AIR WEDGE WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1115 AM...LATEST RADAR TRENDS HAVE INDICATED AN INCREASING
TREND IN RAINFALL RATES ACROSS THE SOUTHERN NC MTNS SE ACROSS THE
SAVANNAH RIVER VALLEY. I WILL INCREASE POPS OVER THE AREA THROUGH
MID DAY. THE REST OF THE CWA HAS MAINLY EXPERIENCED SPRINKLES TO
LIGHT RAIN SHOWERS. THIS TREND MAY CONTINUE OVER THE NEXT COUPLE OF
HOURS. HOWEVER...NEAR TERM MODELS REMAIN IN AGREEMENT WITH SPREADING
COVERAGE EAST ACROSS THE MTNS THIS AFTERNOON WITH THE APPROACH AND
PASSAGE OF A MID LEVEL S/W. I WILL TIME CATE POPS ACROSS THE MTNS
AND ADJACENT FOOTHILLS THIS AFTERNOON. I WILL ALSO COOL TEMPS ACROSS
THE MTNS A COUPLE OF CLICKS...PIEDMONT AREAS APPEARS ON TRACK.
I HAVE ALSO UPDATED THE FORECAST THROUGH SUNDAY. THE MAIN CHANGES
INCLUDE INCREASING POPS AND INDICATING HIGHER QPF OVER UPSLOPE AREAS.
630 AM UPDATE...500MB VORT MAX NOW PASSING THROUGH THE AREA AND
SPARKING A FEW ADDITIONAL SHOWERS OVER THE NW NC PIEDMONT...WHILE
MOST OF THE ACTIVITY REMAINS OVER SW HALF OF CWFA. MADE SOME MORE
ADJUSTMENTS TO POPS INCLUDING SLIGHT EASTWARD EXPANSION TO ACCOUNT
FOR THE PIEDMONT SHOWERS...WHICH LOOK VERY LIGHT ON RADAR AND ARE
NOT LIKELY TO PRODUCE SIGNIFICANT ACCUMS OVER THE NEXT HOUR OR SO.
430 AM UPDATE...ADJUSTED POPS THROUGH DAYBREAK. 06Z NAM DOES NOT
SEEM TO HAVE A GREAT HANDLE ON THE ONGOING PRECIP AROUND THE
REGION...NOT SHOWING ANY ACCUMS FROM THE ACTIVITY IN THE SAVANNAH
RIVER VALLEY. IT DOES CONTINUE TO SUPPORT THE INCREASING POPS NEAR
THE TENN BORDER AFTER SUNRISE. 06Z HRRR SHOWS SOME OF THE CURRENT
ACTIVITY MOVING EAST THEN BRINGS A COUPLE OF WAVES OF SHOWERS ACROSS
BY LATE MORNING. MADE ADJUSTMENTS TO PREVIOUS TREND MOSTLY BASED ON
RADAR MAINLY INTERPRETING THE NEW GUIDANCE AS A CONFIDENCE BOOST.
AS OF EARLY SAT MORNING...SFC HIGH OVER NE CONUS SEEN ON CURRENT SFC
ANALYSIS SITS IN A FAVORABLE POSITION TO ALLOW DEVELOPMENT OF CAD
ACROSS OUR REGION DURING THE NEAR TERM PERIOD. LLVL WINDS ABOVE THE
BOUNDARY LAYER ARE ALREADY SOUTHERLY. THROUGH THE DAY TODAY MIDLEVEL
RIDGE SHIFTS SLIGHTLY EASTWARD AS CLOSED UPPER LOW GROWS OVER THE MID
MISSISSIPPI VALLEY. THE EFFECT WILL BE TO STRENGTHEN THE FLOW OVER
THE CAD WEDGE LEADING TO A SOMEWHAT STEADY INCREASE IN ISENTROPIC
LIFT AND DEEP MOISTURE ADVECTION. MEANWHILE...EXTRA SUPPORT FOR
PRECIP DEVELOPMENT WILL COME FROM VORT MAXES ROUNDING THE SUBTLE
UPPER RIDGE AHEAD OF THE CLOSED LOW. ONE AREA OF PVA IS EXPECTED TO
SPREAD ITS ASSOCIATED PRECIP INTO THE MTNS AROUND DAYBREAK WHILE A
SECOND...SHOWN ON BOTH GFS AND NAM...WILL MOVE THROUGH THIS
AFTERNOON. THAT FEATURE IS CONCURRENT WITH RIGHT REAR QUAD OF 250MB
JET STREAK AND ASSOCIATED DIVERGENCE. UPPER SUPPORT WANES SOMEWHAT ON
GFS THIS EVENING...BUT NAM FEATURES MCV/S MOVING IN AT THAT TIME.
THESE ARE PROBABLY RESULTING FROM CONVECTION UPSTREAM...SO NOT
NECESSARILY BITING ON ANY MODELED EFFECTS FROM THOSE. MIDLEVEL
Q-VECTOR CONVERGENCE DOES CONTINUE TO INCREASE AS HEIGHTS FALL OVER
THE TENN VALLEY AHEAD OF THE UPPER LOW AND AS THE WARM ADVECTION
RAMPS UP.
HAVE NOT MADE MUCH CHANGE TO POP TRENDS WHICH GENERALLY SPREAD WEST
TO EAST DURING THE PERIOD...WITH CATEGORICAL VALUES APPROPRIATE OVER
THE NW HALF OF CWA /WHERE UPSLOPING WILL PLAY THE BIGGEST ROLE AND
ALSO FEATURING THE BEST UPPER SUPPORT/. QPF COULD BE CRITICAL FOR
THIS EVENT AS A WHOLE SO GAVE IT SOME EXTRA THOUGHT. GFS IS THE MOST
ROBUST WITH THE ACTIVITY THIS AFTERNOON WHICH MAKES SENSE GIVEN ITS
EVOLUTION OF THE UPPER FORCING...AND FEATURES LOWER QPF FOR EVENING
BUT WITH SOME INCREASE AGAIN TOWARD SUN MORNING AS THE MOISTURE
DEEPENS. GENERALLY THE DETERMINISTIC TOTALS ARE BACKED UP BY THE
ACCUM PROBABILITIES PRODUCED BY THE ENSEMBLE RUN. CHOSE TO USE A
BLEND OF AVAILABLE DETERMINISTIC GUIDANCE BUT WITH A BIAS TOWARD THE
GFS.
TEMPS TODAY WILL BE BELOW NORMAL GIVEN THE CLOUD COVER AND DEVELOPING
WEDGE...BUT IF PRECIP IS DELAYED OR DOES NOT DEVELOP OVER A
WIDESPREAD AREA TEMPS COULD BE SOMEWHAT WARMER WITHOUT THE RAINFALL
TO LOCK IN THE WEDGE EARLY. WENT WITH RAW MODEL BLEND FOR TONIGHT
ASSUMING THE WEDGE WILL BE FULLY ENTRENCHED BY THEN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 240 AM SATURDAY...AS THE UPPER RIDGE AXIS SHIFTS TO THE
COAST...AND DEEP/VERY MOIST SW FLOW BECOMES ESTABLISHED OVER THE
AREA...POPS WILL CONTINUE TO INCREASE THROUGH SUNDAY WITHIN MODESTLY
STRONG WAA/SOUTHERLY UPSLOPE REGIME. WITH THE CENTER OF THE SURFACE
HIGH EXPECTED TO SHIFT OFF THE NEW ENGLAND COAST BY SUNDAY...IN SITU
COLD AIR DAMMING WILL LIKELY BEGIN TO ERODE AROUND THE PERIPHERY OF
THE FORECAST AREA...ESP THE SOUTHERN PIEDMONT AND FAR SOUTHWEST MTN
ZONES. THIS WILL CREATE THE POTENTIAL FOR INCREASED INSTABILITY/
DEEPER CONVECTION/INCREASED RAINFALL RATES BY AFTERNOON. IN FACT...
SUNDAY AFTERNOON THROUGH SUNDAY NIGHT APPEARS TO BE THE MOST LIKELY
PERIOD OF HEAVY RAINFALL IN LIGHT OF THIS TIME OFFERING THE BEST
JUXTAPOSITION OF UPSLOPE FLOW...INSTABILITY/ MOISTURE...AS WELL AS
INCREASING UPPER LEVEL FORCING. THE LATTER COMES ABOUT AS A RESULT
OF A COUPLED JET STRUCTURE THAT MAXIMIZES SUNDAY EVENING. AREAS
ALONG THE SOUTHERN BLUE RIDGE COULD WELL SEE WIDESPREAD RAINFALL
AMOUNTS OF TWO INCHES WITHIN THIS WINDOW OF TIME ALONE. STORM TOTAL
AMOUNTS OF 2.5 TO 4 INCHES APPEAR TO BE A VERY GOOD BET THROUGH
SUNDAY NIGHT...AND CONFIDENCE IS INCREASING THAT WE MAY HAVE LOCALLY
EXCESSIVE RAINFALL CONCERNS ALONG OUR SOUTHERN BLUE RIDGE COUNTIES.
NEVERTHELESS...I STILL THINK WE ARE AROUND 48 HOURS AWAY FROM SEEING
ANY HYDRO CONCERNS...AND I WOULD LIKE TO SEE HOW TODAY/S RAINFALL
SITUATION UNFOLDS BEFORE HOISTING A WATCH...SO HAVE OPTED TO PUNT TO
THE DAY SHIFT.
BY MONDAY...THE BEST UPPER FORCING AND DEEP MOISTURE WILL SHUNT EAST
OF THE AREA. HOWEVER...SOUTHERLY FLOW WILL PERSIST IN THE LOWER
LEVELS...SUPPORTING AMPLE LOW LEVEL MOISTURE. IN FACT...WITH THE AIR
MASS DRYING SOMEWHAT ALOFT...WE MAY SEE MORE SUN/INSTABILITY MONDAY
AFTERNOON. WITH THE UPPER TROUGH/SHEAR AXIS LINGERING OVER THE
AREA...SOLID CHANCE/LOW LIKELY POPS ARE WARRANTED INTO THE
AFTERNOON. CONVECTION SHOULD BECOME MORE DIURNAL IN NATURE BY THE
END OF THE SHORT TERM PERIOD...SO POPS GRADUALLY TAPER DOWN MONDAY
EVENING.
MAX TEMPERATURES WILL REMAIN BELOW NORMAL SUNDAY UNDER WIDESPREAD
CLOUD COVER AND PRECIPITATION...BUT RETURN TO NEAR CLIMO BY MONDAY.
LOWS WILL BE AT LEAST A CATEGORY ABOVE CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 305 AM SATURDAY...THE MEDIUM RANGE CONTINUES TO APPEAR
UNSETTLED...AS PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW
LEVEL MOISTURE INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES
FOR SHOWERS AND THUNDERSTORMS. THE GLOBAL MODELS CONTINUE TO
ADVERTISE A REASSERTION OF THE EASTERN LOW LEVEL RIDGE AXIS DURING
MID-LATE WEEK. HOWEVER...THEY ARE NOT AS AGGRESSIVE IN DRYING OUT
THE LOWER LEVEL AIR MASS OVER THE CAROLINAS. THERE IS ALSO
CONSIDERABLE UNCERTAINTY REGARDING THE TIMING OF THE NEXT MAJOR
STORM SYSTEM...AS THE PRIMARY GLOBAL MODELS ARE VERY MUCH AT ODDS IN
THEIR HANDLING OF WESTERN CONUS ENERGY LATE IN THE WEEK.
THEREFORE...SLIGHT/CHANCE POPS AND NEAR-CLIMO TEMPS WILL REMAIN IN
THE FORECAST THROUGH THE EXTENDED RANGE PERIOD.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...THE FIELD SHOULD MAINTAIN A SOUTHERLY WIND THROUGH MIDDAY.
WITH HIGH PRESSURE OVER THE MID ATLANTIC COAST HELPING TO DEVELOP
COLD AIR DAMMING AND COOL SFC WEDGE. WARM MOIST FLOW ALOFT OVER THE
WEDGE IS FAIRLY CONSTANT THROUGH THE PERIOD. BETTER UPPER FORCING
AND DEEPENING MOISTURE WILL LEAD TO INCREASING PRECIP CHANCES AND
LOWERING CIGS BY AFTERNOON. BASED ON LATEST GUIDANCE CONSENSUS AND
UPSTREAM ACTIVITY THE SHOWERS ARE NOT EXPECTED TO RESTRICT VSBY.
CIGS SHOULD BE ABLE TO FURTHER DROP TO MVFR BY 06Z...WITH SOME
INDICATION THAT IFR IS POSSIBLE CLOSER TO SUNRISE SUNDAY. WINDS MAY
BE SOMEWHAT VARIABLE THIS AFTERNOON WITH UPPER DISTURBANCE OVERHEAD.
THEY SHOULD TURN BACK TO THE SOUTHEAST AS THE PRECIP AND WEDGE
DEVELOP TONIGHT.
ELSEWHERE...SHOWERS WILL CONTINUE TO DEVELOP THRU THE TAF
PERIOD...WITH RESTRICTIONS BECOMING INCREASINGLY LIKELY...AS WARM
AIR AND MOISTURE ADVECT OVER A WEDGE OF COLD AIR AT THE SURFACE.
SITUATION IS COMPLICATED BY ACTIVE UPPER ATMOSPHERE WHICH WILL
PROVIDE ADDITIONAL LIFT AND ENHANCE PRECIP/CLOUD PRODUCTION AT
TIMES. DO THINK RESTRICTIONS WILL NOT BE SEEN UNTIL AFTERNOON WITH
MOST OF THE UPSTREAM ACTIVITY MAINTAINING LOW VFR EVEN IN SHOWERS.
AS BETTER UPPER SUPPORT MOVES IN TODAY MVFR SHOULD SETTLE IN ACROSS
THE WESTERN PORTIONS OF THE AREA. MVFR CIGS AT KAVL BY
AFTERNOON...AND ELSEWHERE OVERNIGHT. CONDITIONS WILL GENERALLY
CONTINUE TO WORSEN THRU THE END OF THE PERIOD WITH IFR NOT TOTALLY
OUT OF THE QUESTION...LEANING TOWARD MORE OPTIMISTIC GUIDANCE ATTM
AND KEEPING IT MVFR. MAINLY NE TO ENE WINDS WILL PREVAIL WITH THE
WEDGE IN CONTROL.
OUTLOOK...A WEDGE OF COLD AIR WILL PERSIST ACROSS THE REGION SUNDAY
AND MONDAY. PERIODIC PRECIPITATION INTO THIS WEDGE WILL CREATE THE
POSSIBILITY OF FLIGHT RESTRICTIONS.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 100% HIGH 100% HIGH 83% HIGH 81%
KGSP HIGH 100% HIGH 92% HIGH 88% HIGH 100%
KAVL MED 78% MED 78% HIGH 94% HIGH 100%
KHKY HIGH 100% HIGH 97% HIGH 90% HIGH 87%
KGMU HIGH 100% HIGH 92% HIGH 87% HIGH 100%
KAND HIGH 100% HIGH 88% HIGH 83% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...NED/WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
440 AM EDT SAT APR 27 2013
.SYNOPSIS...
AN INCREASINGLY MOIST WEDGE OF COOLER AIR WILL OVERSPREAD THE REGION
THIS WEEKEND AS WEAK LOW PRESSURE MOVES ACROSS THE TENNESSEE VALLEY
ALONG A STALLED COLD FRONT. THE FRONT WILL SLOWLY DISSIPATE AND THE
COOL AIR WEDGE WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
430 AM UPDATE...ADJUSTED POPS THROUGH DAYBREAK. 06Z NAM DOES NOT
SEEM TO HAVE A GREAT HANDLE ON THE ONGOING PRECIP AROUND THE
REGION...NOT SHOWING ANY ACCUMS FROM THE ACTIVITY IN THE SAVANNAH
RIVER VALLEY. IT DOES CONTINUE TO SUPPORT THE INCREASING POPS NEAR
THE TENN BORDER AFTER SUNRISE. 06Z HRRR SHOWS SOME OF THE CURRENT
ACTIVITY MOVING EAST THEN BRINGS A COUPLE OF WAVES OF SHOWERS ACROSS
BY LATE MORNING. MADE ADJUSTMENTS TO PREVIOUS TREND MOSTLY BASED ON
RADAR MAINLY INTERPRETING THE NEW GUIDANCE AS A CONFIDENCE BOOST.
AS OF EARLY SAT MORNING...SFC HIGH OVER NE CONUS SEEN ON CURRENT SFC
ANALYSIS SITS IN A FAVORABLE POSITION TO ALLOW DEVELOPMENT OF CAD
ACROSS OUR REGION DURING THE NEAR TERM PERIOD. LLVL WINDS ABOVE THE
BOUNDARY LAYER ARE ALREADY SOUTHERLY. THROUGH THE DAY TODAY MIDLEVEL
RIDGE SHIFTS SLIGHTLY EASTWARD AS CLOSED UPPER LOW GROWS OVER THE MID
MISSISSIPPI VALLEY. THE EFFECT WILL BE TO STRENGTHEN THE FLOW OVER
THE CAD WEDGE LEADING TO A SOMEWHAT STEADY INCREASE IN ISENTROPIC
LIFT AND DEEP MOISTURE ADVECTION. MEANWHILE...EXTRA SUPPORT FOR
PRECIP DEVELOPMENT WILL COME FROM VORT MAXES ROUNDING THE SUBTLE
UPPER RIDGE AHEAD OF THE CLOSED LOW. ONE AREA OF PVA IS EXPECTED TO
SPREAD ITS ASSOCIATED PRECIP INTO THE MTNS AROUND DAYBREAK WHILE A
SECOND...SHOWN ON BOTH GFS AND NAM...WILL MOVE THROUGH THIS
AFTERNOON. THAT FEATURE IS CONCURRENT WITH RIGHT REAR QUAD OF 250MB
JET STREAK AND ASSOCIATED DIVERGENCE. UPPER SUPPORT WANES SOMEWHAT ON
GFS THIS EVENING...BUT NAM FEATURES MCV/S MOVING IN AT THAT TIME.
THESE ARE PROBABLY RESULTING FROM CONVECTION UPSTREAM...SO NOT
NECESSARILY BITING ON ANY MODELED EFFECTS FROM THOSE. MIDLEVEL
Q-VECTOR CONVERGENCE DOES CONTINUE TO INCREASE AS HEIGHTS FALL OVER
THE TENN VALLEY AHEAD OF THE UPPER LOW AND AS THE WARM ADVECTION
RAMPS UP.
HAVE NOT MADE MUCH CHANGE TO POP TRENDS WHICH GENERALLY SPREAD WEST
TO EAST DURING THE PERIOD...WITH CATEGORICAL VALUES APPROPRIATE OVER
THE NW HALF OF CWA /WHERE UPSLOPING WILL PLAY THE BIGGEST ROLE AND
ALSO FEATURING THE BEST UPPER SUPPORT/. QPF COULD BE CRITICAL FOR
THIS EVENT AS A WHOLE SO GAVE IT SOME EXTRA THOUGHT. GFS IS THE MOST
ROBUST WITH THE ACTIVITY THIS AFTERNOON WHICH MAKES SENSE GIVEN ITS
EVOLUTION OF THE UPPER FORCING...AND FEATURES LOWER QPF FOR EVENING
BUT WITH SOME INCREASE AGAIN TOWARD SUN MORNING AS THE MOISTURE
DEEPENS. GENERALLY THE DETERMINISTIC TOTALS ARE BACKED UP BY THE
ACCUM PROBABILITIES PRODUCED BY THE ENSEMBLE RUN. CHOSE TO USE A
BLEND OF AVAILABLE DETERMINISTIC GUIDANCE BUT WITH A BIAS TOWARD THE
GFS.
TEMPS TODAY WILL BE BELOW NORMAL GIVEN THE CLOUD COVER AND DEVELOPING
WEDGE...BUT IF PRECIP IS DELAYED OR DOES NOT DEVELOP OVER A
WIDESPREAD AREA TEMPS COULD BE SOMEWHAT WARMER WITHOUT THE RAINFALL
TO LOCK IN THE WEDGE EARLY. WENT WITH RAW MODEL BLEND FOR TONIGHT
ASSUMING THE WEDGE WILL BE FULLY ENTRENCHED BY THEN.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 240 AM SATURDAY...AS THE UPPER RIDGE AXIS SHIFTS TO THE
COAST...AND DEEP/VERY MOIST SW FLOW BECOMES ESTABLISHED OVER THE
AREA...POPS WILL CONTINUE TO INCREASE THROUGH SUNDAY WITHIN MODESTLY
STRONG WAA/SOUTHERLY UPSLOPE REGIME. WITH THE CENTER OF THE SURFACE
HIGH EXPECTED TO SHIFT OFF THE NEW ENGLAND COAST BY SUNDAY...IN SITU
COLD AIR DAMMING WILL LIKELY BEGIN TO ERODE AROUND THE PERIPHERY OF
THE FORECAST AREA...ESP THE SOUTHERN PIEDMONT AND FAR SOUTHWEST MTN
ZONES. THIS WILL CREATE THE POTENTIAL FOR INCREASED INSTABILITY/
DEEPER CONVECTION/INCREASED RAINFALL RATES BY AFTERNOON. IN FACT...
SUNDAY AFTERNOON THROUGH SUNDAY NIGHT APPEARS TO BE THE MOST LIKELY
PERIOD OF HEAVY RAINFALL IN LIGHT OF THIS TIME OFFERING THE BEST
JUXTAPOSITION OF UPSLOPE FLOW...INSTABILITY/ MOISTURE...AS WELL AS
INCREASING UPPER LEVEL FORCING. THE LATTER COMES ABOUT AS A RESULT
OF A COUPLED JET STRUCTURE THAT MAXIMIZES SUNDAY EVENING. AREAS
ALONG THE SOUTHERN BLUE RIDGE COULD WELL SEE WIDESPREAD RAINFALL
AMOUNTS OF TWO INCHES WITHIN THIS WINDOW OF TIME ALONE. STORM TOTAL
AMOUNTS OF 2.5 TO 4 INCHES APPEAR TO BE A VERY GOOD BET THROUGH
SUNDAY NIGHT...AND CONFIDENCE IS INCREASING THAT WE MAY HAVE LOCALLY
EXCESSIVE RAINFALL CONCERNS ALONG OUR SOUTHERN BLUE RIDGE COUNTIES.
NEVERTHELESS...I STILL THINK WE ARE AROUND 48 HOURS AWAY FROM SEEING
ANY HYDRO CONCERNS...AND I WOULD LIKE TO SEE HOW TODAY/S RAINFALL
SITUATION UNFOLDS BEFORE HOISTING A WATCH...SO HAVE OPTED TO PUNT TO
THE DAY SHIFT.
BY MONDAY...THE BEST UPPER FORCING AND DEEP MOISTURE WILL SHUNT EAST
OF THE AREA. HOWEVER...SOUTHERLY FLOW WILL PERSIST IN THE LOWER
LEVELS...SUPPORTING AMPLE LOW LEVEL MOISTURE. IN FACT...WITH THE AIR
MASS DRYING SOMEWHAT ALOFT...WE MAY SEE MORE SUN/INSTABILITY MONDAY
AFTERNOON. WITH THE UPPER TROUGH/SHEAR AXIS LINGERING OVER THE
AREA...SOLID CHANCE/LOW LIKELY POPS ARE WARRANTED INTO THE
AFTERNOON. CONVECTION SHOULD BECOME MORE DIURNAL IN NATURE BY THE
END OF THE SHORT TERM PERIOD...SO POPS GRADUALLY TAPER DOWN MONDAY
EVENING.
MAX TEMPERATURES WILL REMAIN BELOW NORMAL SUNDAY UNDER WIDESPREAD
CLOUD COVER AND PRECIPITATION...BUT RETURN TO NEAR CLIMO BY MONDAY.
LOWS WILL BE AT LEAST A CATEGORY ABOVE CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 305 AM SATURDAY...THE MEDIUM RANGE CONTINUES TO APPEAR
UNSETTLED...AS PERSISTENT SOUTH TO SE FLOW MAINTAINS A FETCH OF LOW
LEVEL MOISTURE INTO THE REGION...SUPPORTING MAINLY DIURNAL CHANCES
FOR SHOWERS AND THUNDERSTORMS. THE GLOBAL MODELS CONTINUE TO
ADVERTISE A REASSERTION OF THE EASTERN LOW LEVEL RIDGE AXIS DURING
MID-LATE WEEK. HOWEVER...THEY ARE NOT AS AGGRESSIVE IN DRYING OUT
THE LOWER LEVEL AIR MASS OVER THE CAROLINAS. THERE IS ALSO
CONSIDERABLE UNCERTAINTY REGARDING THE TIMING OF THE NEXT MAJOR
STORM SYSTEM...AS THE PRIMARY GLOBAL MODELS ARE VERY MUCH AT ODDS IN
THEIR HANDLING OF WESTERN CONUS ENERGY LATE IN THE WEEK.
THEREFORE...SLIGHT/CHANCE POPS AND NEAR-CLIMO TEMPS WILL REMAIN IN
THE FORECAST THROUGH THE EXTENDED RANGE PERIOD.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT /09Z UPDATE/...MIDLEVEL CLOUDS NOW OVERHEAD SHOULD REMAIN
VFR THROUGH DAYBREAK AND KEEP DEWPOINT DEPRESSIONS FAR TOO LARGE FOR
ANY FOG RISK. WEAK AREA OF LOW PRESSURE OVER SW VA ASSOCIATED WITH
PASSING UPPER DISTURBANCE PRODUCING A LIGHT SOUTHERLY WIND ATTM WITH
MOST SITES NEARBY BEING CALM. SLY FLOW WILL CONTINUE TO PREVAIL WITH
HIGH PRESSURE OVER THE MID ATLANTIC COAST HELPING TO DEVELOP COLD
AIR DAMMING AND COOL SFC WEDGE. SOUTHERLY FLOW OVER THE WEDGE IS
FAIRLY CONSTANT THROUGH THE PERIOD...BUT BETTER UPPER FORCING AND
DEEPENING MOISTURE WILL LEAD TO INCREASING PRECIP CHANCES AND
LOWERING CIGS BY AFTERNOON...THEN SUFFICIENTLY HIGH FOR A PROB30
SATURDAY EVENING. MODEL CONSENSUS MAINTAINS LOW VFR CIGS THROUGH THE
EVENING BUT THERE IS A CHANCE THEY MAY DROP TO MVFR JUST BEFORE 06Z.
ELSEWHERE...SHOWERS WILL CONTINUE TO DEVELOP THRU THE TAF
PERIOD...WITH RESTRICTIONS BECOMING INCREASINGLY LIKELY...AS WARM
AIR AND MOISTURE ADVECT OVER A WEDGE OF COLD AIR AT THE SURFACE.
SITUATION IS COMPLICATED BY ACTIVE UPPER ATMOSPHERE WHICH WILL
PROVIDE ADDITIONAL LIFT AND ENHANCE PRECIP/CLOUD PRODUCTION AT
TIMES. DO THINK RESTRICTIONS WILL NOT BE SEEN THRU DAYBREAK WITH
MOST OF THE UPSTREAM ACTIVITY MAINTAINING LOW VFR EVEN IN
SHOWERS...THOUGH AS BETTER UPPER SUPPORT MOVES IN TODAY MVFR SHOULD
SETTLE IN ACROSS THE WESTERN PORTIONS OF THE AREA. MVFR CIGS AT KAVL
BY AFTERNOON...AND AT KAND BY EVENING. GUIDANCE SUGGESTS SHOWERS MAY
BRING MVFR VSBY. CONDITIONS WILL GENERALLY CONTINUE TO WORSEN THRU
THE END OF THE PERIOD. MAINLY NE TO ENE WINDS WILL PREVAIL WITH THE
WEDGE IN CONTROL.
OUTLOOK...A WEDGE OF COLD AIR WILL PERSIST ACROSS THE REGION SUNDAY
AND MONDAY. PERIODIC PRECIPITATION INTO THIS WEDGE WILL CREATE THE
POSSIBILITY OF FLIGHT RESTRICTIONS.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 96%
KGSP HIGH 100% HIGH 100% MED 74% MED 60%
KAVL HIGH 93% MED 70% MED 77% HIGH 90%
KHKY HIGH 100% HIGH 98% HIGH 80% MED 75%
KGMU HIGH 100% HIGH 100% MED 75% MED 67%
KAND HIGH 100% HIGH 100% MED 75% LOW 58%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1217 PM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM CDT SAT APR 27 2013
CLEAR SKIES AND WARM TEMPERATURES ON TAP AGAIN FOR TODAY... WITH
TEMPERATURES/HUMIDITY LEVELS THE PRIMARY CHALLENGE OF THE DAY. IN
THE IMMEDIATE TERM...DID ADD SOME PATCHY FOG TO OUR FAR SOUTHEAST
AREAS EARLY THIS MORNING. HIGHER DEW POINTS HAVE BEEN PERSISTING
SOUTH OF WEAKENING RIDGE AXIS OVERNIGHT...AND CAN SOMEWHAT SEE THE
MOISTURE DISCONTINUITY ROUGHLY SOUTH OF VERMILLION TO SPENCER IOWA
LINE ON THE IR SATELLITE IMAGERY THIS MORNING. ANY FOG EXPECTED TO
BE RELATIVELY SHALLOW GIVEN DEVELOPMENT THIS LATE IN THE OVERNIGHT
SO EXPECT IT TO DISSIPATE QUICKLY AS TEMPERATURES BEGIN TO RISE.
WITH SUNSHINE...DEEP DRY ATMOSPHERE...AND RELATIVE DRY GROUND
OUTSIDE THE AREAS WITH MOST RECENT SNOW MELT...TEMPERATURES HAVE BEEN
MIXING TO THE FULLEST AND SEE NO REASON WHY THAT WOULD NOT OCCUR
AGAIN TODAY. THUS HAVE WARMED HIGHS TODAY A LITTLE ABOVE MOST
GUIDANCE...RANGING FROM AROUND 70 OVER THE REMAINING SNOW COVER
ALONG THE BUFFALO RIDGE TO AROUND 80S IN THE WESTERN THIRD OF THE
CWA.
BOUNDARY LAYER DRYING ALSO AN ISSUE...PRIMARILY FOR FIRE WEATHER
CONCERNS. SIMILAR TO YESTERDAY...WOULD EXPECT DRIER AIR TO MIX DOWN
TO THE SURFACE THROUGH THE AFTERNOON. MODELS DID NOT SEEM TO HAVE A
GREAT TRACK RECORD ON DROPPING DOWN THE AFTERNOON DEW POINTS WITH
MIXING YESTERDAY...AND LOOKS LIKE SIMILAR DIFFICULTY MAY BE SEEN
TODAY WITH NAM FORECAST SOUNDINGS SEEMING TO MIX THE SOMEWHAT MORE
MOIST BOUNDARY LAYER UPWARD INSTEAD OF MIXING THE DEEPER DRY AIR
ALOFT DOWNWARD. RAP MODEL SOUNDINGS SEEM TO BETTER REFLECT THIS
THINKING...AND MODEL DEW POINTS RESPOND ACCORDINGLY AND FOLLOWED
THESE MORE CLOSELY FOR DEW POINT/HUMIDITY TRENDS LATER THIS MORNING
THROUGH THE AFTERNOON. THIS WILL RESULT IN HIGH FIRE DANGER ACROSS
OUR WESTERN FORECAST AREA THIS AFTERNOON...BUT WINDS SHOULD BE LIGHT
ENOUGH TO KEEP BELOW VERY HIGH CATEGORY.
START TO SEE SOME INCREASE IN CLOUDS ACROSS OUR NORTHWEST LATER
TONIGHT IN ADVANCE OF UPPER WAVE/ASSOCIATED WEAK COLD FRONT MOVING
INTO THE NORTHERN PLAINS. VERY MILD LOW LEVEL AIR ALONG WITH LIGHT
SOUTHERLY FLOW SHOULD KEEP TEMPERATURES WELL ABOVE NORMAL WITH LOWS
IN THE 40S TO NEAR 50.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 450 AM CDT SAT APR 27 2013
A LITTLE MORE ACTIVE PATTERN SETS UP EARLY NEXT WEEK...INITIALLY
WITH A CHANCE OF LATE AFTERNOON/EVENING SHOWERS OR THUNDERSTORMS
ACROSS OUR EAST SUNDAY AS THE COOL FRONT SLIDES THROUGH A SOMEWHAT
MORE MOIST ATMOSPHERE...THEN WITH A BETTER CHANCE OF RAIN LATER
SUNDAY NIGHT ALONG AND SOUTH OF I-90 AS MID LEVEL MOVES THROUGH THE
REGION. SUNDAY SHOULD BE ANOTHER WARM DAY...LIKELY THE WARMEST OF
THIS STRETCH OVER OUR SOUTHERN AREAS...WHILE THE NORTH SHOULD SEE
TEMPERATURES PEAK MORE IN THE MIDDAY/EARLY AFTERNOON WITH COOLING
THROUGH THE LATER AFTERNOON AS COLD ADVECTION SETS IN AND CLOUDS
INCREASE.
MONDAY WILL BE SLIGHTLY COOLER BEHIND THE FRONT...WITH JUST A CHANCE
OF LINGERING LIGHT RAIN IN OUR FAR SOUTHEAST IN THE MORNING AND
SKIES BECOMING MOSTLY SUNNY AGAIN BY AFTERNOON. WARM RETURN FLOW
QUICKLY SETS LATE MONDAY AFTERNOON/EVENING AND WHILE MID LEVEL
SHOWERS/THUNDERSTORMS ARE POSSIBLE ON THE NOSE OF LOW LEVEL JET...
THIS LOOKS TO BE FOCUSED TO OUR NORTH AND WILL KEEP OUR AREA DRY
THROUGH MONDAY NIGHT.
SHARP COLD FRONT THEN MOVES THROUGH LATE MONDAY NIGHT/TUESDAY...
THOUGH STRONG MIXING BEHIND THE FRONT SHOULD STILL KEEP HIGHS ON
TUESDAY NEAR TO SLIGHTLY ABOVE NORMAL IN THE 60S TO LOWER 70S. 850MB
FRONT STALLS JUST SOUTHEAST OF OUR AREA TUESDAY NIGHT WHILE STRONGER
UPPER TROUGH SWINGS OUT OF THE ROCKIES. THIS WILL BRING INCREASING
RAIN CHANCES TO THE AREA TUESDAY NIGHT INTO WEDNESDAY...MAINLY IN
OUR SOUTHEAST.
SECONDARY COLD FRONT ASSOCIATED WITH THIS WAVE WILL BRING A RETURN
TO BELOW NORMAL TEMPERATURES FROM WEDNESDAY THROUGH THE END OF THE
WEEK. LONG RANGE MODELS VASTLY DIFFERENT ON EVOLUTION OF UPPER
TROUGH AFTER IT PASSES THROUGH OUR AREA WEDNESDAY. GFS DEVELOPS A
CUTOFF LOW OVER THE WESTERN OHIO VALLEY WHILE THE ECMWF BUILDS A
MUCH STRONGER RIDGE OVER THE GREAT LAKES WHICH FORCES THE UPPER LOW
TO DEVELOP OVER THE CENTRAL PLAINS. FORMER WOULD KEEP US DRY THROUGH
THE END OF THE WEEK...WHILE THE LATTER RESULTS IN QUITE A WET PERIOD
FOR PARTS OF THE REGION. GIVEN HIGH DEGREE OF UNCERTAINTY...WILL
KEEP THE LATTER HALF OF THE WEEK DRY FOR NOW...ASIDE FROM LINGERING
LOW CHANCE OF PRECIPITATION IN OUR FAR SOUTHEAST WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1213 PM CDT SAT APR 27 2013
EXPECTING VFR CONDITIONS THROUGH THE PERIOD WITH SOUTH SOUTHWESTERLY
WINDS TODAY AROUND 5 TO 10 KTS. COLD FRONT WILL WORK ACROSS THE AREA
FROM NORTHWEST TO SOUTHEAST TOMORROW...ONLY EXPECTING IT BE THROUGH
KHON BY 18Z...WITH WINDS TURNING NORTH NORTHWESTERLY BEHIND IT AT
AROUND 10 KTS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...JH
LONG TERM...JH
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
546 AM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM CDT SAT APR 27 2013
CLEAR SKIES AND WARM TEMPERATURES ON TAP AGAIN FOR TODAY... WITH
TEMPERATURES/HUMIDITY LEVELS THE PRIMARY CHALLENGE OF THE DAY. IN
THE IMMEDIATE TERM...DID ADD SOME PATCHY FOG TO OUR FAR SOUTHEAST
AREAS EARLY THIS MORNING. HIGHER DEW POINTS HAVE BEEN PERSISTING
SOUTH OF WEAKENING RIDGE AXIS OVERNIGHT...AND CAN SOMEWHAT SEE THE
MOISTURE DISCONTINUITY ROUGHLY SOUTH OF VERMILLION TO SPENCER IOWA
LINE ON THE IR SATELLITE IMAGERY THIS MORNING. ANY FOG EXPECTED TO
BE RELATIVELY SHALLOW GIVEN DEVELOPMENT THIS LATE IN THE OVERNIGHT
SO EXPECT IT TO DISSIPATE QUICKLY AS TEMPERATURES BEGIN TO RISE.
WITH SUNSHINE...DEEP DRY ATMOSPHERE...AND RELATIVE DRY GROUND
OUTSIDE THE AREAS WITH MOST RECENT SNOW MELT...TEMPERATURES HAVE BEEN
MIXING TO THE FULLEST AND SEE NO REASON WHY THAT WOULD NOT OCCUR
AGAIN TODAY. THUS HAVE WARMED HIGHS TODAY A LITTLE ABOVE MOST
GUIDANCE...RANGING FROM AROUND 70 OVER THE REMAINING SNOW COVER
ALONG THE BUFFALO RIDGE TO AROUND 80S IN THE WESTERN THIRD OF THE
CWA.
BOUNDARY LAYER DRYING ALSO AN ISSUE...PRIMARILY FOR FIRE WEATHER
CONCERNS. SIMILAR TO YESTERDAY...WOULD EXPECT DRIER AIR TO MIX DOWN
TO THE SURFACE THROUGH THE AFTERNOON. MODELS DID NOT SEEM TO HAVE A
GREAT TRACK RECORD ON DROPPING DOWN THE AFTERNOON DEW POINTS WITH
MIXING YESTERDAY...AND LOOKS LIKE SIMILAR DIFFICULTY MAY BE SEEN
TODAY WITH NAM FORECAST SOUNDINGS SEEMING TO MIX THE SOMEWHAT MORE
MOIST BOUNDARY LAYER UPWARD INSTEAD OF MIXING THE DEEPER DRY AIR
ALOFT DOWNWARD. RAP MODEL SOUNDINGS SEEM TO BETTER REFLECT THIS
THINKING...AND MODEL DEW POINTS RESPOND ACCORDINGLY AND FOLLOWED
THESE MORE CLOSELY FOR DEW POINT/HUMIDITY TRENDS LATER THIS MORNING
THROUGH THE AFTERNOON. THIS WILL RESULT IN HIGH FIRE DANGER ACROSS
OUR WESTERN FORECAST AREA THIS AFTERNOON...BUT WINDS SHOULD BE LIGHT
ENOUGH TO KEEP BELOW VERY HIGH CATEGORY.
START TO SEE SOME INCREASE IN CLOUDS ACROSS OUR NORTHWEST LATER
TONIGHT IN ADVANCE OF UPPER WAVE/ASSOCIATED WEAK COLD FRONT MOVING
INTO THE NORTHERN PLAINS. VERY MILD LOW LEVEL AIR ALONG WITH LIGHT
SOUTHERLY FLOW SHOULD KEEP TEMPERATURES WELL ABOVE NORMAL WITH LOWS
IN THE 40S TO NEAR 50.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 450 AM CDT SAT APR 27 2013
A LITTLE MORE ACTIVE PATTERN SETS UP EARLY NEXT WEEK...INITIALLY
WITH A CHANCE OF LATE AFTERNOON/EVENING SHOWERS OR THUNDERSTORMS
ACROSS OUR EAST SUNDAY AS THE COOL FRONT SLIDES THROUGH A SOMEWHAT
MORE MOIST ATMOSPHERE...THEN WITH A BETTER CHANCE OF RAIN LATER
SUNDAY NIGHT ALONG AND SOUTH OF I-90 AS MID LEVEL MOVES THROUGH THE
REGION. SUNDAY SHOULD BE ANOTHER WARM DAY...LIKELY THE WARMEST OF
THIS STRETCH OVER OUR SOUTHERN AREAS...WHILE THE NORTH SHOULD SEE
TEMPERATURES PEAK MORE IN THE MIDDAY/EARLY AFTERNOON WITH COOLING
THROUGH THE LATER AFTERNOON AS COLD ADVECTION SETS IN AND CLOUDS
INCREASE.
MONDAY WILL BE SLIGHTLY COOLER BEHIND THE FRONT...WITH JUST A CHANCE
OF LINGERING LIGHT RAIN IN OUR FAR SOUTHEAST IN THE MORNING AND
SKIES BECOMING MOSTLY SUNNY AGAIN BY AFTERNOON. WARM RETURN FLOW
QUICKLY SETS LATE MONDAY AFTERNOON/EVENING AND WHILE MID LEVEL
SHOWERS/THUNDERSTORMS ARE POSSIBLE ON THE NOSE OF LOW LEVEL JET...
THIS LOOKS TO BE FOCUSED TO OUR NORTH AND WILL KEEP OUR AREA DRY
THROUGH MONDAY NIGHT.
SHARP COLD FRONT THEN MOVES THROUGH LATE MONDAY NIGHT/TUESDAY...
THOUGH STRONG MIXING BEHIND THE FRONT SHOULD STILL KEEP HIGHS ON
TUESDAY NEAR TO SLIGHTLY ABOVE NORMAL IN THE 60S TO LOWER 70S. 850MB
FRONT STALLS JUST SOUTHEAST OF OUR AREA TUESDAY NIGHT WHILE STRONGER
UPPER TROUGH SWINGS OUT OF THE ROCKIES. THIS WILL BRING INCREASING
RAIN CHANCES TO THE AREA TUESDAY NIGHT INTO WEDNESDAY...MAINLY IN
OUR SOUTHEAST.
SECONDARY COLD FRONT ASSOCIATED WITH THIS WAVE WILL BRING A RETURN
TO BELOW NORMAL TEMPERATURES FROM WEDNESDAY THROUGH THE END OF THE
WEEK. LONG RANGE MODELS VASTLY DIFFERENT ON EVOLUTION OF UPPER
TROUGH AFTER IT PASSES THROUGH OUR AREA WEDNESDAY. GFS DEVELOPS A
CUTOFF LOW OVER THE WESTERN OHIO VALLEY WHILE THE ECMWF BUILDS A
MUCH STRONGER RIDGE OVER THE GREAT LAKES WHICH FORCES THE UPPER LOW
TO DEVELOP OVER THE CENTRAL PLAINS. FORMER WOULD KEEP US DRY THROUGH
THE END OF THE WEEK...WHILE THE LATTER RESULTS IN QUITE A WET PERIOD
FOR PARTS OF THE REGION. GIVEN HIGH DEGREE OF UNCERTAINTY...WILL
KEEP THE LATTER HALF OF THE WEEK DRY FOR NOW...ASIDE FROM LINGERING
LOW CHANCE OF PRECIPITATION IN OUR FAR SOUTHEAST WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 547 AM CDT SAT APR 27 2013
AREAS OF VISIBILITIES 3-5SM IN LIGHT FOG THROUGH 15Z OVER THE
SOUTHEAST CORNER OF THE AREA...FROM SUX TO SLB...WITH VERY LOCAL
CEILINGS BELOW 1K FEET AND VISIBILITIES BELOW 3SM IN FOG THROUGH
15Z IN THE SAME PART OF THE AREA. THE FOG SHOULD DISSIPATE BY
15Z...OTHERWISE VFR IS EXPECTED OVER THE AREA THROUGH 28/12Z.
STRONGER SURFACE AND LOW LEVEL FLOW SHOULD PREVENT ANY LOWERING OF
CONDITIONS NEAR THE END OF THE PERIOD.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...JH
LONG TERM...JH
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
450 AM CDT SAT APR 27 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM CDT SAT APR 27 2013
CLEAR SKIES AND WARM TEMPERATURES ON TAP AGAIN FOR TODAY... WITH
TEMPERATURES/HUMIDITY LEVELS THE PRIMARY CHALLENGE OF THE DAY. IN
THE IMMEDIATE TERM...DID ADD SOME PATCHY FOG TO OUR FAR SOUTHEAST
AREAS EARLY THIS MORNING. HIGHER DEW POINTS HAVE BEEN PERSISTING
SOUTH OF WEAKENING RIDGE AXIS OVERNIGHT...AND CAN SOMEWHAT SEE THE
MOISTURE DISCONTINUITY ROUGHLY SOUTH OF VERMILLION TO SPENCER IOWA
LINE ON THE IR SATELLITE IMAGERY THIS MORNING. ANY FOG EXPECTED TO
BE RELATIVELY SHALLOW GIVEN DEVELOPMENT THIS LATE IN THE OVERNIGHT
SO EXPECT IT TO DISSIPATE QUICKLY AS TEMPERATURES BEGIN TO RISE.
WITH SUNSHINE...DEEP DRY ATMOSPHERE...AND RELATIVE DRY GROUND
OUTSIDE THE AREAS WITH MOST RECENT SNOW MELT...TEMPERATURES HAVE BEEN
MIXING TO THE FULLEST AND SEE NO REASON WHY THAT WOULD NOT OCCUR
AGAIN TODAY. THUS HAVE WARMED HIGHS TODAY A LITTLE ABOVE MOST
GUIDANCE...RANGING FROM AROUND 70 OVER THE REMAINING SNOW COVER
ALONG THE BUFFALO RIDGE TO AROUND 80S IN THE WESTERN THIRD OF THE
CWA.
BOUNDARY LAYER DRYING ALSO AN ISSUE...PRIMARILY FOR FIRE WEATHER
CONCERNS. SIMILAR TO YESTERDAY...WOULD EXPECT DRIER AIR TO MIX DOWN
TO THE SURFACE THROUGH THE AFTERNOON. MODELS DID NOT SEEM TO HAVE A
GREAT TRACK RECORD ON DROPPING DOWN THE AFTERNOON DEW POINTS WITH
MIXING YESTERDAY...AND LOOKS LIKE SIMILAR DIFFICULTY MAY BE SEEN
TODAY WITH NAM FORECAST SOUNDINGS SEEMING TO MIX THE SOMEWHAT MORE
MOIST BOUNDARY LAYER UPWARD INSTEAD OF MIXING THE DEEPER DRY AIR
ALOFT DOWNWARD. RAP MODEL SOUNDINGS SEEM TO BETTER REFLECT THIS
THINKING...AND MODEL DEW POINTS RESPOND ACCORDINGLY AND FOLLOWED
THESE MORE CLOSELY FOR DEW POINT/HUMIDITY TRENDS LATER THIS MORNING
THROUGH THE AFTERNOON. THIS WILL RESULT IN HIGH FIRE DANGER ACROSS
OUR WESTERN FORECAST AREA THIS AFTERNOON...BUT WINDS SHOULD BE LIGHT
ENOUGH TO KEEP BELOW VERY HIGH CATEGORY.
START TO SEE SOME INCREASE IN CLOUDS ACROSS OUR NORTHWEST LATER
TONIGHT IN ADVANCE OF UPPER WAVE/ASSOCIATED WEAK COLD FRONT MOVING
INTO THE NORTHERN PLAINS. VERY MILD LOW LEVEL AIR ALONG WITH LIGHT
SOUTHERLY FLOW SHOULD KEEP TEMPERATURES WELL ABOVE NORMAL WITH LOWS
IN THE 40S TO NEAR 50.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 450 AM CDT SAT APR 27 2013
A LITTLE MORE ACTIVE PATTERN SETS UP EARLY NEXT WEEK...INITIALLY
WITH A CHANCE OF LATE AFTERNOON/EVENING SHOWERS OR THUNDERSTORMS
ACROSS OUR EAST SUNDAY AS THE COOL FRONT SLIDES THROUGH A SOMEWHAT
MORE MOIST ATMOSPHERE...THEN WITH A BETTER CHANCE OF RAIN LATER
SUNDAY NIGHT ALONG AND SOUTH OF I-90 AS MID LEVEL MOVES THROUGH THE
REGION. SUNDAY SHOULD BE ANOTHER WARM DAY...LIKELY THE WARMEST OF
THIS STRETCH OVER OUR SOUTHERN AREAS...WHILE THE NORTH SHOULD SEE
TEMPERATURES PEAK MORE IN THE MIDDAY/EARLY AFTERNOON WITH COOLING
THROUGH THE LATER AFTERNOON AS COLD ADVECTION SETS IN AND CLOUDS
INCREASE.
MONDAY WILL BE SLIGHTLY COOLER BEHIND THE FRONT...WITH JUST A CHANCE
OF LINGERING LIGHT RAIN IN OUR FAR SOUTHEAST IN THE MORNING AND
SKIES BECOMING MOSTLY SUNNY AGAIN BY AFTERNOON. WARM RETURN FLOW
QUICKLY SETS LATE MONDAY AFTERNOON/EVENING AND WHILE MID LEVEL
SHOWERS/THUNDERSTORMS ARE POSSIBLE ON THE NOSE OF LOW LEVEL JET...
THIS LOOKS TO BE FOCUSED TO OUR NORTH AND WILL KEEP OUR AREA DRY
THROUGH MONDAY NIGHT.
SHARP COLD FRONT THEN MOVES THROUGH LATE MONDAY NIGHT/TUESDAY...
THOUGH STRONG MIXING BEHIND THE FRONT SHOULD STILL KEEP HIGHS ON
TUESDAY NEAR TO SLIGHTLY ABOVE NORMAL IN THE 60S TO LOWER 70S. 850MB
FRONT STALLS JUST SOUTHEAST OF OUR AREA TUESDAY NIGHT WHILE STRONGER
UPPER TROUGH SWINGS OUT OF THE ROCKIES. THIS WILL BRING INCREASING
RAIN CHANCES TO THE AREA TUESDAY NIGHT INTO WEDNESDAY...MAINLY IN
OUR SOUTHEAST.
SECONDARY COLD FRONT ASSOCIATED WITH THIS WAVE WILL BRING A RETURN
TO BELOW NORMAL TEMPERATURES FROM WEDNESDAY THROUGH THE END OF THE
WEEK. LONG RANGE MODELS VASTLY DIFFERENT ON EVOLUTION OF UPPER
TROUGH AFTER IT PASSES THROUGH OUR AREA WEDNESDAY. GFS DEVELOPS A
CUTOFF LOW OVER THE WESTERN OHIO VALLEY WHILE THE ECMWF BUILDS A
MUCH STRONGER RIDGE OVER THE GREAT LAKES WHICH FORCES THE UPPER LOW
TO DEVELOP OVER THE CENTRAL PLAINS. FORMER WOULD KEEP US DRY THROUGH
THE END OF THE WEEK...WHILE THE LATTER RESULTS IN QUITE A WET PERIOD
FOR PARTS OF THE REGION. GIVEN HIGH DEGREE OF UNCERTAINTY...WILL
KEEP THE LATTER HALF OF THE WEEK DRY FOR NOW...ASIDE FROM LINGERING
LOW CHANCE OF PRECIPITATION IN OUR FAR SOUTHEAST WEDNESDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1032 PM CDT FRI APR 26 2013
VFR THROUGH 06Z SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...JH
LONG TERM...JH
AVIATION...
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1245 PM CDT SAT APR 27 2013
.AVIATION UPDATE...FOR 18Z TAF PACKAGE...
LATEST RADAR TRENDS INDICATE RAIN SHIELD MOSTLY EAST OF I65
CORRIDOR. STILL SCATTERED SHOWERS BEING OBSERVED ACROSS WESTERN
AND SOUTHERN MIDDLE TN AT TAF ISSUANCE. VISIBILITIES ARE CLEARING
UP AT KBNA AND KCKV AS WELL. WARM FRONT IS STILL WELL SOUTH OF THE
CWA SO ONLY WENT WITH VCSH FOR KBNA TO PREVAIL FOR THE FIRST FEW
HOURS. THIS AFTERNOON...SCATTERED SHOWERS AND THUNDERSTORMS WILL
REDEVELOP IN THE VICINITY OF KBNA AND KCKV. THESE STORMS WILL
LIKELY BE ORIENTED ALONG THE WARM FRONT AND MOVE NORTHEASTWARD.
AMENDMENTS MAY BE REQUIRED AS IMPACTS TO TERMINALS BECOMES MORE
CLEAR THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 913 AM CDT SAT APR 27 2013/
MESOSCALE UPDATE...
AT 14Z WARM FRONT DRAPED ACROSS SOUTHERN ARKANSAS AND NORTHERN
MISSISSIPPI SOUTH OF CLARKDALE. MID STATE WELL NORTH OF WARM FRONT
AND ON COOL SIDE WITH WIDESPREAD SHOWERS STRUNG OUT FROM WEST TO
EAST ACROSS WEST AND MIDDLE TENNESSEE WORKING EASTWARD. THERE IS A
SMALL CLUSTER OF THUNDERSTORMS CURRENTLY IN PERRY COUNTY WITH A
FEW MORE STORMS STILL IN WESTERN TENNESSEE YET TO COME EAST.
INFRARED CLOUD TOPS HAVE REMAINED COLD LAST FEW IMAGES WITH NO
SIGN OF WARMING. BELIEVE BEST CHANCE FOR LIGHTNING THROUGH 21Z WILL
BE SOUTH OF INTERSTATE 40...THIS BASED ON LATEST SREF RUN.
LOOKS LIKE FRONT IS GOING TO BE SLOW LIFTING NORTH DURING THE DAY
AS UPPER LEVEL ENERGY STILL REMAINS WELL WEST OF SURFACE BOUNDARY.
SURFACE LOW THIS MORNING CENTERED SOUTH OF FORT SMITH AND IS
FORECAST TO MOVE EASTWARD DURING THE DAY AND BE NEAR MEMPHIS BY
00Z THIS EVENING. AM EXPECTING WARM FRONT TO BEGIN LIFTING NORTH
AND INTO SOUTHWEST MIDDLE TENNESSEE AFTER 20Z TODAY WITH
INCREASING CAPES AND INSTABILITY ALONG WITH RISING SURFACE TEMPS
AND DEWPOINTS OVER THE SOUTHWESTERN AREAS DURING THE LATE
AFTERNOON AND WORK NORTHEASTWARD INTO MIDDLE TENNESSEE DURING THE
EARLY EVENING. THINK A FEW STRONG TO SEVERE STORMS ARE POSSIBLE
DURING THE LATE AFTERNOON/EVENING ESPECIALLY SOUTHWEST MIDDLE TENNESSEE
WHERE INSTABILITY LOOKS TO BE THE STRONGEST...BUT ISOLATED SEVERE
CANT BE RULED OUT ELSEWHERE IN THE MID STATE FROM MID TO LATE
EVENING AS INSTABILITY TRIES TO COME NORTH ALONG SURFACE BOUNDARY.
AS FOR TODAYS HIGHS...WARMER TEMPS WILL BE IN THE SOUTHWEST WHERE I
HAVE LOWER 70S WITH 60S ELSEWHERE. ONCE THIS INITIAL ROUND OF
SHOWERS AND ISOLATED THUNDERSTORMS GETS TO OUR EAST AM EXPECTING
NEW DEVELOPMENT TO TAKE PLACE. ALL IN ALL IT LOOKS VERY MUCH LIKE
A WET SATURDAY.
BOYD
PREV DISCUSSION... /ISSUED 716 AM CDT SAT APR 27 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...TODAY WILL BE CHARACTERIZED BY STRONG WARM ADVECTION
IN A VERY MOIST AIRMASS AS UPPER LEVEL LOW OVER KS MOVES SLOWLY
INTO MO. NUMEROUS SHOWERS AND SOME THUNDERSTORMS...ALONG WITH LOW
CIGS AND 3 TO 5 MILE VSBYS...WILL SPREAD ACROSS CKV...BNA...AND
CSV THIS MORNING. MUCH OF THE RAIN WILL DIMINISH BY 18Z AT CKV
.BY 20Z AT BNA...AND BY 22Z AT CSV. HOWEVER...SHOWERS AND STORMS
WILL RETURN OVERNIGHT ACROSS THE ENTIRE REGION AS UPPER TROF
MOVES FROM MO EASTWARD THROUGH THE OHIO VALLEY. A TRAILING WEAK COLD
FRONT WILL MOVE THROUGH MIDDLE TN ON SUNDAY AS THE UPPER TROF
HEADS TOWARD THE GREAT LAKES.
PREV DISCUSSION... /ISSUED 417 AM CDT SAT APR 27 2013/
SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND TONIGHT...
WIDESPREAD RAIN AND THUNDERSTORMS TO CONTINUE THIS WEEKEND...
SHORT TERM...
LATEST RADAR IMAGERY SHOWS WIDESPREAD LIGHT TO MODERATE RAIN
CONTINUES ACROSS MOST OF THE FORECAST AREA...WITH MORE ISOLATED
SHOWERS ACROSS WAYNE/LAWRENCE/GILES COUNTIES. PRECIPITATION
IS BEING AIDED BY A WEAK SHORTWAVE TROUGH EVIDENT ACROSS EASTERN
TENNESSEE...AND IS FOCUSED ALONG AND NORTH OF A 850 MB WARM FRONT
THAT CURRENTLY EXTENDS FROM DYERSBURG TO WINCHESTER. PRECIPITATION
WILL CONTINUE TO BE GENERATED TODAY DUE TO SUSTAINED WAA ABOVE
THE FRONTAL SURFACE...WITH RENEWED DEVELOPMENT TO OUR WEST AS THE
NEXT WEAK SHORTWAVE CURRENTLY SEEN ALONG THE MISSISSIPPI RIVER
APPROACHES. INDEED...MOSAIC RADAR IMAGERY SHOWS A LARGE AREA OF
SHOWERS AND THUNDERSTORMS HAS ALREADY REDEVELOPED IN WESTERN
TENNESSEE WHICH WILL MOVE ACROSS THE CWA LATER THIS MORNING.
HEAVIEST ACTIVITY IS EXPECTED TO BE IN AN ARC FROM NORTHWEST TO
SOUTHEAST ACROSS THE CENTER OF THE CWA...WITH FAR SOUTHWEST AND
NORTHEAST AREAS SEEING MORE SCATTERED ACTIVITY.
BY AFTERNOON...SOME GLOBAL AND MESOSCALE MODELS DEPICT A BREAK IN
THE WIDESPREAD RAINFALL AS SHORTWAVE CURRENTLY ALONG THE MS RIVER
MOVES OFF TO THE EAST. HAVE THUS LOWERED POPS INTO THE LIKELY
CATEGORY THIS AFTERNOON...BUT REMAINS UNCERTAIN HOW MUCH OF A
BREAK WILL BE SEEN AS OTHER MODELS SUCH AS THE HRRR CONTINUE
PRECIPITATION NONSTOP. REGARDLESS...MAIN UPPER LOW SEEN ON WATER
VAPOR IMAGERY ACROSS OK/KS WILL APPROACH THE MISSISSIPPI RIVER
LATER THIS AFTERNOON AND EVENING. AS THIS OCCURS...A WEAK SURFACE
LOW IS PROGGED BY MODELS TO DEVELOP IN NORTHEAST ARKANSAS THEN
MOVE NORTHEAST INTO SOUTHERN KENTUCKY TONIGHT. STRENGTHENING WIND
FIELDS AND HIGHER SURFACE DEWPOINTS ADVECTING NORTHWARD COMBINED
WITH SOME DIURNAL HEATING SHOULD ALLOW FOR DESTABILIZATION OF THE
LOWER LEVELS OVER WESTERN ZONES. ALL GUIDANCE DEVELOPS ADDITIONAL
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING ACROSS
WEST TENNESSEE AND NORTH MISSISSIPPI WHICH THEN MOVE INTO THE MID
STATE THROUGH SATURDAY NIGHT. FORECAST SOUNDINGS SHOW WEAK TO
MODERATE INSTABILITY/SHEAR WITH RELATIVELY COLD MID
LEVELS LATER TODAY...SUGGESTING DAMAGING WINDS AND LARGE HAIL
WOULD BE POSSIBLE WITH THE STRONGEST STORMS. INDEED...MESOSCALE
MODELS SHOW SOME ROBUST STORMS IN OUR WESTERN COUNTIES AROUND 00Z
THIS EVENING. SPC HAS UPGRADED PORTIONS OF WESTERN ZONES INTO A
SLIGHT RISK FOR THIS AFTERNOON AND TONIGHT. EASTWARD EXTENT OF ANY
SEVERE ACTIVITY THAT MAY DEVELOP WILL BE GREATLY LIMITED BY MORE
STABLE CONDITIONS EAST OF THE SLIGHT RISK AREA.
GUIDANCE DEPICTS A DRY SLOT ALOFT ADVANCING ACROSS WESTERN
PORTIONS OF THE MID STATE ON SUNDAY AS UPPER LOW ADVANCES THROUGH
THE OHIO VALLEY. THIS WILL LOWER PRECIP CHANCES OVER THE WEST WITH
HIGH POPS CONTINUING OVER THE EAST. ALL ACTIVITY SHOULD WIND DOWN
BY SUNDAY NIGHT AS UPPER LOW MOVES EAST OF THE REGION. TOTAL
RAINFALL AMOUNTS FOR THIS WEEKEND RAIN EVENT APPEAR TO BE IN THE 1
TO 2 INCH RANGE NORTH OF I-40 WITH 2 TO 3 INCHES SOUTH OF
I-40...BUT SOME 4 INCH AMOUNTS ARE POSSIBLE WITH ANY SUSTAINED
HEAVIER THUNDERSTORMS. ALTHOUGH NO WIDESPREAD FLASH FLOODING IS
EXPECTED...SOME LOCALIZED FLOODING IS CERTAINLY POSSIBLE AND
RUNOFF INTO AREA RIVERS MAY RESULT IN SOME RISING INTO ACTION
STAGE NEXT WEEK.
LONG TERM...
WARMER AND DRIER WEATHER IS ANTICIPATED FOR MONDAY AND TUESDAY AS
WEAK RIDGING ALOFT BUILDS OVER THE TENNESSEE VALLEY REGION. LOW
PRECIP CHANCES RETURN BY WEDNESDAY AS A WEAK UPPER LOW DEVELOPS
IN THE GULF COAST STATES. FOR THE END OF THE FORECAST
PERIOD...00Z GFS/ECMWF HAVE CONTINUED THE HIGHLY ANOMALOUS TREND
OF THE PAST FEW DAYS IN DEVELOPING A LARGE AND INTENSE CUT OFF H5
LOW WHICH THEN MEANDERS FOR DAYS ACROSS THE EASTERN CONUS.
UNFORTUNATELY...GFS AND ECMWF DIFFER BY 600 MILES ON THEIR
PLACEMENT OF THE UPPER LOW WHICH RESULTS IN TEMPERATURE
DIFFERENCES OF 20 DEGREES OR MORE FOR HIGHS AND LOWS. FOR NOW
WILL GO WITH LOW POPS FOR THE END OF NEXT WEEK AND TREND
TEMPERATURES TOWARDS THE COLDER MEX GUIDANCE...ALTHOUGH FORECAST
IN THE LONG RANGE SHOULD BE CONSIDERED EXTREMELY LOW CONFIDENCE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
913 AM CDT SAT APR 27 2013
.MESOSCALE UPDATE...
AT 14Z WARM FRONT DRAPED ACROSS SOUTHERN ARKANSAS AND NORTHERN
MISSISSIPPI SOUTH OF CLARKDALE. MID STATE WELL NORTH OF WARM FRONT
AND ON COOL SIDE WITH WIDESPREAD SHOWERS STRUNG OUT FROM WEST TO
EAST ACROSS WEST AND MIDDLE TENNESSEE WORKING EASTWARD. THERE IS A
SMALL CLUSTER OF THUNDERSTORMS CURRENTLY IN PERRY COUNTY WITH A
FEW MORE STORMS STILL IN WESTERN TENNESSEE YET TO COME EAST.
INFRARED CLOUD TOPS HAVE REMAINED COLD LAST FEW IMAGES WITH NO
SIGN OF WARMING. BELIEVE BEST CHANCE FOR LIGHTNING THROUGH 21Z WILL
BE SOUTH OF INTERSTATE 40...THIS BASED ON LATEST SREF RUN.
LOOKS LIKE FRONT IS GOING TO BE SLOW LIFTING NORTH DURING THE DAY
AS UPPER LEVEL ENERGY STILL REMAINS WELL WEST OF SURFACE BOUNDARY.
SURFACE LOW THIS MORNING CENTERED SOUTH OF FORT SMITH AND IS
FORECAST TO MOVE EASTWARD DURING THE DAY AND BE NEAR MEMPHIS BY
00Z THIS EVENING. AM EXPECTING WARM FRONT TO BEGIN LIFTING NORTH
AND INTO SOUTHWEST MIDDLE TENNESSEE AFTER 20Z TODAY WITH
INCREASING CAPES AND INSTABILITY ALONG WITH RISING SURFACE TEMPS
AND DEWPOINTS OVER THE SOUTHWESTERN AREAS DURING THE LATE
AFTERNOON AND WORK NORTHEASTWARD INTO MIDDLE TENNESSEE DURING THE
EARLY EVENING. THINK A FEW STRONG TO SEVERE STORMS ARE POSSIBLE
DURING THE LATE AFTERNOON/EVENING ESPECIALLY SOUTHWEST MIDDLE TENNESSEE
WHERE INSTABILITY LOOKS TO BE THE STRONGEST...BUT ISOLATED SEVERE
CANT BE RULED OUT ELSEWHERE IN THE MID STATE FROM MID TO LATE
EVENING AS INSTABILITY TRIES TO COME NORTH ALONG SURFACE BOUNDARY.
AS FOR TODAYS HIGHS...WARMER TEMPS WILL BE IN THE SOUTHWEST WHERE I
HAVE LOWER 70S WITH 60S ELSEWHERE. ONCE THIS INITIAL ROUND OF
SHOWERS AND ISOLATED THUNDERSTORMS GETS TO OUR EAST AM EXPECTING
NEW DEVELOPMENT TO TAKE PLACE. ALL IN ALL IT LOOKS VERY MUCH LIKE
A WET SATURDAY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 716 AM CDT SAT APR 27 2013/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...TODAY WILL BE CHARACTERIZED BY STRONG WARM ADVECTION
IN A VERY MOIST AIRMASS AS UPPER LEVEL LOW OVER KS MOVES SLOWLY
INTO MO. NUMEROUS SHOWERS AND SOME THUNDERSTORMS...ALONG WITH LOW
CIGS AND 3 TO 5 MILE VSBYS...WILL SPREAD ACROSS CKV...BNA...AND
CSV THIS MORNING. MUCH OF THE RAIN WILL DIMINISH BY 18Z AT CKV
..BY 20Z AT BNA...AND BY 22Z AT CSV. HOWEVER...SHOWERS AND STORMS
WILL RETURN OVERNIGHT ACROSS THE ENTIRE REGION AS UPPER TROF
MOVES FROM MO EASTWARD THROUGH THE OHIO VALLEY. A TRAILING WEAK COLD
FRONT WILL MOVE THROUGH MIDDLE TN ON SUNDAY AS THE UPPER TROF
HEADS TOWARD THE GREAT LAKES.
PREV DISCUSSION... /ISSUED 417 AM CDT SAT APR 27 2013/
.SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND TONIGHT...
.WIDESPREAD RAIN AND THUNDERSTORMS TO CONTINUE THIS WEEKEND...
SHORT TERM...
LATEST RADAR IMAGERY SHOWS WIDESPREAD LIGHT TO MODERATE RAIN
CONTINUES ACROSS MOST OF THE FORECAST AREA...WITH MORE ISOLATED
SHOWERS ACROSS WAYNE/LAWRENCE/GILES COUNTIES. PRECIPITATION
IS BEING AIDED BY A WEAK SHORTWAVE TROUGH EVIDENT ACROSS EASTERN
TENNESSEE...AND IS FOCUSED ALONG AND NORTH OF A 850 MB WARM FRONT
THAT CURRENTLY EXTENDS FROM DYERSBURG TO WINCHESTER. PRECIPITATION
WILL CONTINUE TO BE GENERATED TODAY DUE TO SUSTAINED WAA ABOVE
THE FRONTAL SURFACE...WITH RENEWED DEVELOPMENT TO OUR WEST AS THE
NEXT WEAK SHORTWAVE CURRENTLY SEEN ALONG THE MISSISSIPPI RIVER
APPROACHES. INDEED...MOSAIC RADAR IMAGERY SHOWS A LARGE AREA OF
SHOWERS AND THUNDERSTORMS HAS ALREADY REDEVELOPED IN WESTERN
TENNESSEE WHICH WILL MOVE ACROSS THE CWA LATER THIS MORNING.
HEAVIEST ACTIVITY IS EXPECTED TO BE IN AN ARC FROM NORTHWEST TO
SOUTHEAST ACROSS THE CENTER OF THE CWA...WITH FAR SOUTHWEST AND
NORTHEAST AREAS SEEING MORE SCATTERED ACTIVITY.
BY AFTERNOON...SOME GLOBAL AND MESOSCALE MODELS DEPICT A BREAK IN
THE WIDESPREAD RAINFALL AS SHORTWAVE CURRENTLY ALONG THE MS RIVER
MOVES OFF TO THE EAST. HAVE THUS LOWERED POPS INTO THE LIKELY
CATEGORY THIS AFTERNOON...BUT REMAINS UNCERTAIN HOW MUCH OF A
BREAK WILL BE SEEN AS OTHER MODELS SUCH AS THE HRRR CONTINUE
PRECIPITATION NONSTOP. REGARDLESS...MAIN UPPER LOW SEEN ON WATER
VAPOR IMAGERY ACROSS OK/KS WILL APPROACH THE MISSISSIPPI RIVER
LATER THIS AFTERNOON AND EVENING. AS THIS OCCURS...A WEAK SURFACE
LOW IS PROGGED BY MODELS TO DEVELOP IN NORTHEAST ARKANSAS THEN
MOVE NORTHEAST INTO SOUTHERN KENTUCKY TONIGHT. STRENGTHENING WIND
FIELDS AND HIGHER SURFACE DEWPOINTS ADVECTING NORTHWARD COMBINED
WITH SOME DIURNAL HEATING SHOULD ALLOW FOR DESTABILIZATION OF THE
LOWER LEVELS OVER WESTERN ZONES. ALL GUIDANCE DEVELOPS ADDITIONAL
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING ACROSS
WEST TENNESSEE AND NORTH MISSISSIPPI WHICH THEN MOVE INTO THE MID
STATE THROUGH SATURDAY NIGHT. FORECAST SOUNDINGS SHOW WEAK TO
MODERATE INSTABILITY/SHEAR WITH RELATIVELY COLD MID
LEVELS LATER TODAY...SUGGESTING DAMAGING WINDS AND LARGE HAIL
WOULD BE POSSIBLE WITH THE STRONGEST STORMS. INDEED...MESOSCALE
MODELS SHOW SOME ROBUST STORMS IN OUR WESTERN COUNTIES AROUND 00Z
THIS EVENING. SPC HAS UPGRADED PORTIONS OF WESTERN ZONES INTO A
SLIGHT RISK FOR THIS AFTERNOON AND TONIGHT. EASTWARD EXTENT OF ANY
SEVERE ACTIVITY THAT MAY DEVELOP WILL BE GREATLY LIMITED BY MORE
STABLE CONDITIONS EAST OF THE SLIGHT RISK AREA.
GUIDANCE DEPICTS A DRY SLOT ALOFT ADVANCING ACROSS WESTERN
PORTIONS OF THE MID STATE ON SUNDAY AS UPPER LOW ADVANCES THROUGH
THE OHIO VALLEY. THIS WILL LOWER PRECIP CHANCES OVER THE WEST WITH
HIGH POPS CONTINUING OVER THE EAST. ALL ACTIVITY SHOULD WIND DOWN
BY SUNDAY NIGHT AS UPPER LOW MOVES EAST OF THE REGION. TOTAL
RAINFALL AMOUNTS FOR THIS WEEKEND RAIN EVENT APPEAR TO BE IN THE 1
TO 2 INCH RANGE NORTH OF I-40 WITH 2 TO 3 INCHES SOUTH OF
I-40...BUT SOME 4 INCH AMOUNTS ARE POSSIBLE WITH ANY SUSTAINED
HEAVIER THUNDERSTORMS. ALTHOUGH NO WIDESPREAD FLASH FLOODING IS
EXPECTED...SOME LOCALIZED FLOODING IS CERTAINLY POSSIBLE AND
RUNOFF INTO AREA RIVERS MAY RESULT IN SOME RISING INTO ACTION
STAGE NEXT WEEK.
LONG TERM...
WARMER AND DRIER WEATHER IS ANTICIPATED FOR MONDAY AND TUESDAY AS
WEAK RIDGING ALOFT BUILDS OVER THE TENNESSEE VALLEY REGION. LOW
PRECIP CHANCES RETURN BY WEDNESDAY AS A WEAK UPPER LOW DEVELOPS
IN THE GULF COAST STATES. FOR THE END OF THE FORECAST
PERIOD...00Z GFS/ECMWF HAVE CONTINUED THE HIGHLY ANOMALOUS TREND
OF THE PAST FEW DAYS IN DEVELOPING A LARGE AND INTENSE CUT OFF H5
LOW WHICH THEN MEANDERS FOR DAYS ACROSS THE EASTERN CONUS.
UNFORTUNATELY...GFS AND ECMWF DIFFER BY 600 MILES ON THEIR
PLACEMENT OF THE UPPER LOW WHICH RESULTS IN TEMPERATURE
DIFFERENCES OF 20 DEGREES OR MORE FOR HIGHS AND LOWS. FOR NOW
WILL GO WITH LOW POPS FOR THE END OF NEXT WEEK AND TREND
TEMPERATURES TOWARDS THE COLDER MEX GUIDANCE...ALTHOUGH FORECAST
IN THE LONG RANGE SHOULD BE CONSIDERED EXTREMELY LOW CONFIDENCE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
716 AM CDT SAT APR 27 2013
.UPDATE...FOR 12Z AVIATION FORECAST
&&
.AVIATION...TODAY WILL BE CHARACTERIZED BY STRONG WARM ADVECTION
IN A VERY MOIST AIRMASS AS UPPER LEVEL LOW OVER KS MOVES SLOWLY
INTO MO. NUMEROUS SHOWERS AND SOME THUNDERSTORMS...ALONG WITH LOW
CIGS AND 3 TO 5 MILE VSBYS...WILL SPREAD ACROSS CKV...BNA...AND
CSV THIS MORNING. MUCH OF THE RAIN WILL DIMINISH BY 18Z AT CKV
...BY 20Z AT BNA...AND BY 22Z AT CSV. HOWEVER...SHOWERS AND STORMS
WILL RETURN OVERNIGHT ACROSS THE ENTIRE REGION AS UPPER TROF
MOVES FROM MO EASTWARD THROUGH THE OHIO VALLEY. A TRAILING WEAK COLD
FRONT WILL MOVE THROUGH MIDDLE TN ON SUNDAY AS THE UPPER TROF
HEADS TOWARD THE GREAT LAKES.
&&
.PREV DISCUSSION... /ISSUED 417 AM CDT SAT APR 27 2013/
..SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND TONIGHT...
..WIDESPREAD RAIN AND THUNDERSTORMS TO CONTINUE THIS WEEKEND...
SHORT TERM...
LATEST RADAR IMAGERY SHOWS WIDESPREAD LIGHT TO MODERATE RAIN
CONTINUES ACROSS MOST OF THE FORECAST AREA...WITH MORE ISOLATED
SHOWERS ACROSS WAYNE/LAWRENCE/GILES COUNTIES. PRECIPITATION
IS BEING AIDED BY A WEAK SHORTWAVE TROUGH EVIDENT ACROSS EASTERN
TENNESSEE...AND IS FOCUSED ALONG AND NORTH OF A 850 MB WARM FRONT
THAT CURRENTLY EXTENDS FROM DYERSBURG TO WINCHESTER. PRECIPITATION
WILL CONTINUE TO BE GENERATED TODAY DUE TO SUSTAINED WAA ABOVE
THE FRONTAL SURFACE...WITH RENEWED DEVELOPMENT TO OUR WEST AS THE
NEXT WEAK SHORTWAVE CURRENTLY SEEN ALONG THE MISSISSIPPI RIVER
APPROACHES. INDEED...MOSAIC RADAR IMAGERY SHOWS A LARGE AREA OF
SHOWERS AND THUNDERSTORMS HAS ALREADY REDEVELOPED IN WESTERN
TENNESSEE WHICH WILL MOVE ACROSS THE CWA LATER THIS MORNING.
HEAVIEST ACTIVITY IS EXPECTED TO BE IN AN ARC FROM NORTHWEST TO
SOUTHEAST ACROSS THE CENTER OF THE CWA...WITH FAR SOUTHWEST AND
NORTHEAST AREAS SEEING MORE SCATTERED ACTIVITY.
BY AFTERNOON...SOME GLOBAL AND MESOSCALE MODELS DEPICT A BREAK IN
THE WIDESPREAD RAINFALL AS SHORTWAVE CURRENTLY ALONG THE MS RIVER
MOVES OFF TO THE EAST. HAVE THUS LOWERED POPS INTO THE LIKELY
CATEGORY THIS AFTERNOON...BUT REMAINS UNCERTAIN HOW MUCH OF A
BREAK WILL BE SEEN AS OTHER MODELS SUCH AS THE HRRR CONTINUE
PRECIPITATION NONSTOP. REGARDLESS...MAIN UPPER LOW SEEN ON WATER
VAPOR IMAGERY ACROSS OK/KS WILL APPROACH THE MISSISSIPPI RIVER
LATER THIS AFTERNOON AND EVENING. AS THIS OCCURS...A WEAK SURFACE
LOW IS PROGGED BY MODELS TO DEVELOP IN NORTHEAST ARKANSAS THEN
MOVE NORTHEAST INTO SOUTHERN KENTUCKY TONIGHT. STRENGTHENING WIND
FIELDS AND HIGHER SURFACE DEWPOINTS ADVECTING NORTHWARD COMBINED
WITH SOME DIURNAL HEATING SHOULD ALLOW FOR DESTABILIZATION OF THE
LOWER LEVELS OVER WESTERN ZONES. ALL GUIDANCE DEVELOPS ADDITIONAL
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING ACROSS
WEST TENNESSEE AND NORTH MISSISSIPPI WHICH THEN MOVE INTO THE MID
STATE THROUGH SATURDAY NIGHT. FORECAST SOUNDINGS SHOW WEAK TO
MODERATE INSTABILITY/SHEAR WITH RELATIVELY COLD MID
LEVELS LATER TODAY...SUGGESTING DAMAGING WINDS AND LARGE HAIL
WOULD BE POSSIBLE WITH THE STRONGEST STORMS. INDEED...MESOSCALE
MODELS SHOW SOME ROBUST STORMS IN OUR WESTERN COUNTIES AROUND 00Z
THIS EVENING. SPC HAS UPGRADED PORTIONS OF WESTERN ZONES INTO A
SLIGHT RISK FOR THIS AFTERNOON AND TONIGHT. EASTWARD EXTENT OF ANY
SEVERE ACTIVITY THAT MAY DEVELOP WILL BE GREATLY LIMITED BY MORE
STABLE CONDITIONS EAST OF THE SLIGHT RISK AREA.
GUIDANCE DEPICTS A DRY SLOT ALOFT ADVANCING ACROSS WESTERN
PORTIONS OF THE MID STATE ON SUNDAY AS UPPER LOW ADVANCES THROUGH
THE OHIO VALLEY. THIS WILL LOWER PRECIP CHANCES OVER THE WEST WITH
HIGH POPS CONTINUING OVER THE EAST. ALL ACTIVITY SHOULD WIND DOWN
BY SUNDAY NIGHT AS UPPER LOW MOVES EAST OF THE REGION. TOTAL
RAINFALL AMOUNTS FOR THIS WEEKEND RAIN EVENT APPEAR TO BE IN THE 1
TO 2 INCH RANGE NORTH OF I-40 WITH 2 TO 3 INCHES SOUTH OF
I-40...BUT SOME 4 INCH AMOUNTS ARE POSSIBLE WITH ANY SUSTAINED
HEAVIER THUNDERSTORMS. ALTHOUGH NO WIDESPREAD FLASH FLOODING IS
EXPECTED...SOME LOCALIZED FLOODING IS CERTAINLY POSSIBLE AND
RUNOFF INTO AREA RIVERS MAY RESULT IN SOME RISING INTO ACTION
STAGE NEXT WEEK.
LONG TERM...
WARMER AND DRIER WEATHER IS ANTICIPATED FOR MONDAY AND TUESDAY AS
WEAK RIDGING ALOFT BUILDS OVER THE TENNESSEE VALLEY REGION. LOW
PRECIP CHANCES RETURN BY WEDNESDAY AS A WEAK UPPER LOW DEVELOPS
IN THE GULF COAST STATES. FOR THE END OF THE FORECAST
PERIOD...00Z GFS/ECMWF HAVE CONTINUED THE HIGHLY ANOMALOUS TREND
OF THE PAST FEW DAYS IN DEVELOPING A LARGE AND INTENSE CUT OFF H5
LOW WHICH THEN MEANDERS FOR DAYS ACROSS THE EASTERN CONUS.
UNFORTUNATELY...GFS AND ECMWF DIFFER BY 600 MILES ON THEIR
PLACEMENT OF THE UPPER LOW WHICH RESULTS IN TEMPERATURE
DIFFERENCES OF 20 DEGREES OR MORE FOR HIGHS AND LOWS. FOR NOW
WILL GO WITH LOW POPS FOR THE END OF NEXT WEEK AND TREND
TEMPERATURES TOWARDS THE COLDER MEX GUIDANCE...ALTHOUGH FORECAST
IN THE LONG RANGE SHOULD BE CONSIDERED EXTREMELY LOW CONFIDENCE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
49
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
417 AM CDT SAT APR 27 2013
...SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND TONIGHT...
...WIDESPREAD RAIN AND THUNDERSTORMS TO CONTINUE THIS WEEKEND...
.SHORT TERM...
LATEST RADAR IMAGERY SHOWS WIDESPREAD LIGHT TO MODERATE RAIN
CONTINUES ACROSS MOST OF THE FORECAST AREA...WITH MORE ISOLATED
SHOWERS ACROSS WAYNE/LAWRENCE/GILES COUNTIES. PRECIPITATION
IS BEING AIDED BY A WEAK SHORTWAVE TROUGH EVIDENT ACROSS EASTERN
TENNESSEE...AND IS FOCUSED ALONG AND NORTH OF A 850 MB WARM FRONT
THAT CURRENTLY EXTENDS FROM DYERSBURG TO WINCHESTER. PRECIPITATION
WILL CONTINUE TO BE GENERATED TODAY DUE TO SUSTAINED WAA ABOVE
THE FRONTAL SURFACE...WITH RENEWED DEVELOPMENT TO OUR WEST AS THE
NEXT WEAK SHORTWAVE CURRENTLY SEEN ALONG THE MISSISSIPPI RIVER
APPROACHES. INDEED...MOSAIC RADAR IMAGERY SHOWS A LARGE AREA OF
SHOWERS AND THUNDERSTORMS HAS ALREADY REDEVELOPED IN WESTERN
TENNESSEE WHICH WILL MOVE ACROSS THE CWA LATER THIS MORNING.
HEAVIEST ACTIVITY IS EXPECTED TO BE IN AN ARC FROM NORTHWEST TO
SOUTHEAST ACROSS THE CENTER OF THE CWA...WITH FAR SOUTHWEST AND
NORTHEAST AREAS SEEING MORE SCATTERED ACTIVITY.
BY AFTERNOON...SOME GLOBAL AND MESOSCALE MODELS DEPICT A BREAK IN
THE WIDESPREAD RAINFALL AS SHORTWAVE CURRENTLY ALONG THE MS RIVER
MOVES OFF TO THE EAST. HAVE THUS LOWERED POPS INTO THE LIKELY
CATEGORY THIS AFTERNOON...BUT REMAINS UNCERTAIN HOW MUCH OF A
BREAK WILL BE SEEN AS OTHER MODELS SUCH AS THE HRRR CONTINUE
PRECIPITATION NONSTOP. REGARDLESS...MAIN UPPER LOW SEEN ON WATER
VAPOR IMAGERY ACROSS OK/KS WILL APPROACH THE MISSISSIPPI RIVER
LATER THIS AFTERNOON AND EVENING. AS THIS OCCURS...A WEAK SURFACE
LOW IS PROGGED BY MODELS TO DEVELOP IN NORTHEAST ARKANSAS THEN
MOVE NORTHEAST INTO SOUTHERN KENTUCKY TONIGHT. STRENGTHENING WIND
FIELDS AND HIGHER SURFACE DEWPOINTS ADVECTING NORTHWARD COMBINED
WITH SOME DIURNAL HEATING SHOULD ALLOW FOR DESTABILIZATION OF THE
LOWER LEVELS OVER WESTERN ZONES. ALL GUIDANCE DEVELOPS ADDITIONAL
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING ACROSS
WEST TENNESSEE AND NORTH MISSISSIPPI WHICH THEN MOVE INTO THE MID
STATE THROUGH SATURDAY NIGHT. FORECAST SOUNDINGS SHOW WEAK TO
MODERATE INSTABILITY/SHEAR WITH RELATIVELY COLD MID
LEVELS LATER TODAY...SUGGESTING DAMAGING WINDS AND LARGE HAIL
WOULD BE POSSIBLE WITH THE STRONGEST STORMS. INDEED...MESOSCALE
MODELS SHOW SOME ROBUST STORMS IN OUR WESTERN COUNTIES AROUND 00Z
THIS EVENING. SPC HAS UPGRADED PORTIONS OF WESTERN ZONES INTO A
SLIGHT RISK FOR THIS AFTERNOON AND TONIGHT. EASTWARD EXTENT OF ANY
SEVERE ACTIVITY THAT MAY DEVELOP WILL BE GREATLY LIMITED BY MORE
STABLE CONDITIONS EAST OF THE SLIGHT RISK AREA.
GUIDANCE DEPICTS A DRY SLOT ALOFT ADVANCING ACROSS WESTERN
PORTIONS OF THE MID STATE ON SUNDAY AS UPPER LOW ADVANCES THROUGH
THE OHIO VALLEY. THIS WILL LOWER PRECIP CHANCES OVER THE WEST WITH
HIGH POPS CONTINUING OVER THE EAST. ALL ACTIVITY SHOULD WIND DOWN
BY SUNDAY NIGHT AS UPPER LOW MOVES EAST OF THE REGION. TOTAL
RAINFALL AMOUNTS FOR THIS WEEKEND RAIN EVENT APPEAR TO BE IN THE 1
TO 2 INCH RANGE NORTH OF I-40 WITH 2 TO 3 INCHES SOUTH OF
I-40...BUT SOME 4 INCH AMOUNTS ARE POSSIBLE WITH ANY SUSTAINED
HEAVIER THUNDERSTORMS. ALTHOUGH NO WIDESPREAD FLASH FLOODING IS
EXPECTED...SOME LOCALIZED FLOODING IS CERTAINLY POSSIBLE AND
RUNOFF INTO AREA RIVERS MAY RESULT IN SOME RISING INTO ACTION
STAGE NEXT WEEK.
.LONG TERM...
WARMER AND DRIER WEATHER IS ANTICIPATED FOR MONDAY AND TUESDAY AS
WEAK RIDGING ALOFT BUILDS OVER THE TENNESSEE VALLEY REGION. LOW
PRECIP CHANCES RETURN BY WEDNESDAY AS A WEAK UPPER LOW DEVELOPS
IN THE GULF COAST STATES. FOR THE END OF THE FORECAST
PERIOD...00Z GFS/ECMWF HAVE CONTINUED THE HIGHLY ANOMALOUS TREND
OF THE PAST FEW DAYS IN DEVELOPING A LARGE AND INTENSE CUT OFF H5
LOW WHICH THEN MEANDERS FOR DAYS ACROSS THE EASTERN CONUS.
UNFORTUNATELY...GFS AND ECMWF DIFFER BY 600 MILES ON THEIR
PLACEMENT OF THE UPPER LOW WHICH RESULTS IN TEMPERATURE
DIFFERENCES OF 20 DEGREES OR MORE FOR HIGHS AND LOWS. FOR NOW
WILL GO WITH LOW POPS FOR THE END OF NEXT WEEK AND TREND
TEMPERATURES TOWARDS THE COLDER MEX GUIDANCE...ALTHOUGH FORECAST
IN THE LONG RANGE SHOULD BE CONSIDERED EXTREMELY LOW CONFIDENCE.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 65 57 73 55 / 100 80 50 10
CLARKSVILLE 64 57 72 52 / 100 80 40 05
CROSSVILLE 60 54 67 53 / 100 80 70 30
COLUMBIA 68 58 73 55 / 100 80 50 10
LAWRENCEBURG 70 59 73 54 / 80 80 50 20
WAVERLY 66 57 71 52 / 100 80 40 0
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
125 PM CDT SAT APR 27 2013
.UPDATE...
A QUICK UPDATE HAS BEEN SENT TO LOWER THIS AFTERNOON/S HIGHS BY A
FEW DEGREES ACROSS THE NORTHERN HALF OF THE FORECAST AREA. HAVE
ALSO TRIMMED THE POPS FROM AREAS NORTH OF A GOLDTHWAITE TO ATHENS
LINE.
58
&&
.AVIATION...
STRATUS BURNING OFF FROM WEST...AND TIMING THE WESTERN EDGE INTO
METROPLEX GIVES VFR CONDITIONS BY 19Z. WACO CURRENTLY CLEAR...BUT
SATELLITE SHOWS SCT VFR CU FAIRLY CLOSE.
METROPLEX EXPECTED TO REMAIN CLEAR THROUGH END OF TAF CYCLE AND
BEYOND...BUT CONVECTION EXPECTED TO DEVELOP SOUTH OF WACO AND
ANVIL SHIELD WILL LIKELY GROW NORTH LATER TODAY THROUGH MOST OF
THE NIGHT. THERE REMAINS A LOW THREAT OF THUNDER/SHOWERS
OVERNIGHT...BUT BASED ON HI RES GUIDANCE FEEL THAT RAIN WILL STAY
SOUTH OF THE WACO AIRPORT.
SOUTH FLOW RETURNS TOMORROW. 84
&&
.PREV UPDATE...
.UPDATE...
A COLD FRONT EXTENDED FROM JUST WEST OF PARIS TO SOUTHEAST OF
GREENVILLE...TERRELL...WEST...GATESVILLE AND LAMPASAS AT 16Z.
THIS FRONT WILL MOVE THROUGH WACO IN THE NEXT HALF HOUR...BUT
STALL OUT OVER THE SOUTHEASTERN PART OF THE FORECAST AREA THIS
AFTERNOON. HAVE ADJUSTED THE HOURLY WIND/TEMPERATURE/DEW POINT
GRIDS BASED ON THE LATEST RUC GUIDANCE WHICH SEEMS TO BE IN LINE
WITH ONGOING TRENDS.
THE 06Z TEXAS TECH WRF AND THE LATEST /12Z/ HIGH RESOLUTION RAPID
REFRESH...INDICATE THAT MOST OF THE SHOWERS AND THUNDERSTORMS
WILL BE TO THE SOUTH OF THE FORECAST AREA THIS AFTERNOON WITH A
LITTLE MORE MOVING INTO THE SOUTHEASTERN ZONES AFTER 23Z. FOR
NOW...HAVE LEFT POPS AS IS...BUT WE MAY BE ABLE TO TRIM A LITTLE
OFF LATER THIS AFTERNOON DEPENDING ON EXACTLY WHERE THE FRONT
STALLS.
58
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 27 2013/
EARLY MORNING WATER VAPOR IMAGERY DEPICTED A CYCLONIC CIRCULATION
CENTERED OVER SOUTH CENTRAL KS OR NORTH CENTRAL OK MOVING EAST.
THIS CIRCULATION WAS LOCATED ON THE EAST END OF A POSITIVELY
TILTED CYCLONIC SHEAR AXIS EXTENDING WSW OVER THE TX PANHANDLE AND
OVER WEST CENTRAL AZ. TO THE EAST OF THE KS/OK UPPER LOW WAS A
LINE OF LOOSELY ORGANIZED THUNDERSTORMS LOCATED FROM NORTHWESTERN
AR SOUTHWEST TO SOUTHEAST OK. 08Z /3AM/ SURFACE OBSERVATIONS
DEPICTED A COLD FRONT LOCATED NEAR A BOWIE TO PK LAKE TO COMANCHE
LINE MOVING SOUTHEAST. THE FWD 00Z RAOB INDICATED A SUBSTANTIAL
CAP IN PLACE OVER NORTH TX...AND THIS CAP WAS LIKELY RESPONSIBLE
FOR THE DEARTH OF PRECIPITATION ALONG THE PORTION OF THE FRONT IN
TEXAS EARLY THIS MORNING.
TODAY AND TONIGHT...GUIDANCE CONSISTENTLY INDICATES THAT THE
CYCLONIC CIRCULATION/UPPER LOW OVER THE KS/OK BORDER EARLY THIS
MORNING WILL DEEPEN INTO A CLOSED LOW WHILE MOVING EAST OVER THE
NEXT 24 HRS. THIS WILL CAUSE THE CYCLONIC SHEAR AXIS TO SWING
SOUTHEAST IN ITS WAKE OVER THE CWA LATE THIS AFTERNOON THROUGH THE
OVERNIGHT HRS. THE EVOLUTION OF THIS UPPER LEVEL SYSTEM WILL HAVE
SOME INTERESTING IMPACTS ON SURFACE FEATURES ACROSS NORTH AND
CENTRAL TX TODAY.
THE SURFACE LOW THAT WAS LOCATED JUST EAST OF WICHITA FALLS AT THE
TIME OF THIS DISCUSSION IS EXPECTED TO MOVE EAST NORTHEAST WITH
THE MAIN UPPER LOW OVER THE NEXT 24 HRS. THIS WILL CAUSE THE COLD
FRONT TO CONTINUE SOUTH ACROSS THE CWA THROUGH THIS AFTERNOON. AS
THE SURFACE LOW IS MOVING EAST ACROSS AR TODAY ANOTHER SURFACE LOW
IS EXPECTED TO DEVELOP OVER NORTHERN MEXICO TO THE WEST OF DEL RIO
IN RESPONSE TO THE CYCLONIC SHEAR AXIS MOVING SOUTHEAST. WITH A
NEW SURFACE LOW DEVELOPING TO THE SOUTHWEST...AND THE OTHER
SURFACE LOW MOVING OFF TO THE EAST...THE COLD FRONT WILL LIKELY
STALL OUT NEAR OR JUST SOUTHEAST OF A LINE FROM ATHENS TO WACO BY
THE MID-AFTERNOON HOURS.
OVERNIGHT MODELS ARE STILL NOT IN COMPLETE AGREEMENT AS TO WHERE
THE FRONT WILL COME TO A REST...BUT SOMEWHERE BETWEEN WACO AND
COLLEGE STATION IS THE CONSENSUS LOCATION. WHEREVER THE FRONT
STALLS...WITH LOW PRESSURE OFF TO THE NORTHEAST AND
SOUTHWEST...THE GENERAL LOW LEVEL WIND FIELD LOOKS TO BE
DOMINATED BY VERY WEAK DEFORMATION ON EITHER SIDE OF THE STALLED
FRONT THIS AFTERNOON. WEAK NORTHEAST WINDS NORTH OF THE FRONT AND
WEAK SOUTHWEST WINDS TO THE SOUTH WILL ACTUALLY MINIMIZE PURE
CONVERGENCE ALONG THE FRONT...MAKING IT VERY DIFFICULT TO
DETERMINE IF THE FRONT WILL BE AN IMPORTANT SOURCE OF LIFT THIS
AFTERNOON.
TEMPERATURES WILL GENERALLY BE WARMER SOUTHEAST OF THE
FRONT...BUT THE GULF MOISTURE IN PLACE WILL ACTUALLY SUPPORT
CLOUDIER CONDITIONS TO THE SOUTHEAST OF THE FRONT THIS AFTERNOON.
DRIER AIR TO THE NORTH COMBINED WITH SUBSIDENCE IN THE WAKE OF THE
DEPARTING UPPER LOW WILL CAUSE SKIES TO CLEAR OUT NORTH OF THE
FRONT. AFTERNOON SUNSHINE WILL WEAKEN THE TEMPERATURE GRADIENT
ALONG THE FRONT...REDUCING FRONTOGENETIC FORCING DURING THE PEAK
HEATING HRS OF THE DAY. AS A RESULT THINK MESOSCALE FORCING FOR
ASCENT ALONG THE FRONT WILL BE FAIRLY WEAK THIS AFTERNOON...
REDUCING CONFIDENCE IN CONVECTION INITIATION ALONG THE STALLED OUT
FRONT DURING THE PEAK HEATING HRS OF THE DAY.
AS A RESULT...BUMPED POPS DOWN A LITTLE BIT THRU SUNSET FOR
LOCATIONS ALONG AND SOUTH OF A LINE FROM COMANCHE TO CANTON.
GUIDANCE CONTINUES TO INDICATE THAT THERE WILL BE OVER 2000 J/KG
OF CAPE AVAILABLE FOR FREE CONVECTION IF STORMS CAN DEVELOP ALONG
THE FRONT. THEREFORE DESPITE THE LOW POPS...WILL CONTINUE TO
MENTION A CHANCE OF STRONG TO SEVERE STORMS AS ANYTHING THAT DOES
MANAGE TO DEVELOP WILL LIKELY BE QUITE STRONG THIS AFTERNOON.
DAMAGING WINDS AND LARGE HAIL WOULD BE THE MOST LIKELY HAZARDS IF
ANYTHING WERE ABLE TO DEVELOP ALONG THE FRONT THRU SUNSET.
TONIGHT...THE DRIER AIR TO THE NORTH WILL ACTUALLY HELP INCREASE
THE THERMAL GRADIENT ALONG THE STALLED OUT FRONT AS THIS AIR WILL
COOL MORE QUICKLY THAN THE CLOUDY AND MORE MOIST AIRMASS TO THE
SOUTH OF THE FRONT. AS A RESULT...EVEN THOUGH THIS SEEMS
COUNTER-INTUITIVE...OUR BEST CHANCES FOR STORMS ALONG THE FRONT MAY
BE WELL AFTER SUNSET TONIGHT. MODELS DO NOT REALLY INDICATE A BIG
INCREASE IN CONVERGENCE ALONG THE FRONT...BUT THE INCREASE IN THE
THERMAL GRADIENT WILL LEAD TO STRONGER MESOSCALE FORCING FOR
ASCENT. THIS COMBINED WITH THE MEAGER LARGE SCALE SUPPORT OFFERED
BY THE CYCLONIC SHEAR AXIS MOVING OVER THE REGION HAS CONFIDENCE A
BIT HIGHER IN STORMS ALONG THE FRONT AFTER SUNSET. AS A RESULT
WENT AHEAD AND BUMPED UP POPS FROM 00-12Z ALONG THE FRONT FOR
TONIGHT. SEVERE WEATHER CHANCES WILL NOT BE AS GREAT AFTER
SUNSET...HOWEVER LARGE HAIL IS STILL A POSSIBILITY WITH THE
STRONGEST STORMS. ANY STORMS THAT DEVELOP WILL LIKELY MOVE
PARALLEL TO THE FRONT...SO THERE IS A RISK FOR LOCALLY HEAVY
RAINFALL DUE TO THE POTENTIAL FOR STORMS TO TRAIN ALONG THE FRONT
TONIGHT. THAT SAID...POPS ARE ONLY IN THE 30 TO 40 PERCENT CHANCE
RANGE...SO IT IS STILL POSSIBLE THAT FORCING REMAINS TOO WEAK FOR
ANYTHING ALONG THE FRONT OVERNIGHT.
SUNDAY THROUGH TUESDAY...GUIDANCE INDICATES THAT WEAK UPPER LEVEL
RIDGING WILL BUILD OVER THE NORTHERN PORTIONS OF THE SOUTH PLAINS
DURING THE PERIOD WHICH SHOULD HELP KEEP US DRY. THE ECMWF
STUBBORNLY INDICATES THAT THE TAILING END OF THE CYCLONIC SHEAR
AXIS MOVING SOUTH OVER TX TONIGHT WILL BECOME ISOLATED FROM THE
DEPARTING UPPER LOW/SHEAR AXIS AND FORM A WEAK CUT-OFF UPPER LOW
OVER THE TX GULF COAST DURING THIS PERIOD. BASED ON THE ECMWFS
EVOLUTION AND TRACK OF THIS FEATURE...IT IS SOMEWHAT
INCONSEQUENTIAL TO NORTH AND CENTRAL TX AS WE WOULD REMAIN NORTH
OR NORTHWEST OF THIS UPPER LOW THRU THE PERIOD. THE ECMWF HAS BEEN
CONSISTENT WITH THIS FEATURE...SO CONFIDENCE IS HIGHER THAT IT
WILL DEVELOP...HOWEVER THIS SHOULD JUST REINFORCE RIDGING OVER THE
CWA INCREASING CONFIDENCE IN A DRY FORECAST FROM SUNDAY AFTERNOON
THRU TUESDAY. EVEN IF THE UPPER LOW DEVELOPS...IT IS EXPECTED TO
REMAIN TOO WEAK TO HAVE A LARGE IMPACT ON THE SURFACE PRESSURE
PATTERN...THEREFORE WE SHOULD REMAIN IN SOUTHERLY FLOW DUE TO LEE
SIDE TROUGHING IN RESPONSE TO A POWERFUL UPPER LOW EXPECTED TO
SWING INTO THE PLAINS MID-WEEK. SOUTH WINDS AND SUBSIDENCE ALOFT
SHOULD HELP US BRING TEMPERATURES UP INTO THE 80S DURING THIS
PERIOD.
MID-WEEK...MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE ON THE
EXACT EVOLUTION OF THE POWERFUL SYSTEM PROGGED TO MOVE OVER THE
PLAINS WEDNESDAY OR WEDNESDAY NIGHT. ASIDE FROM THE FAIRLY LARGE
PLACEMENT DISCREPANCIES BETWEEN THE GFS AND CANADIAN/ECMWF ALL
GUIDANCE AGREES THAT THIS UPPER LEVEL SYSTEM WILL BE UNSEASONABLY
STRONG AND MAY LEAD TO AN EXTENDED PERIOD OF BELOW NORMAL
TEMPERATURES FOR NORTH TX FOR THE FIRST SEVERAL DAYS OF MAY. THIS
FORECAST IS MOST IN LINE WITH THE CONSENSUS OF THE ECMWF/CANADIAN
OPERATIONAL MODELS THAT WERE VALID AT 27/00Z. THESE MODELS BRING
THE INITIAL UPPER LEVEL LOW OVER THE SOUTH PLAINS DRIVING A STRONG
COLD FRONT SOUTH ACROSS NORTH TX LATE WEDNESDAY AFTERNOON THRU THE
OVERNIGHT HRS.
ASSUMING THE UPPER LOW DIGS AS FAR SOUTH AS THESE MODELS
INDICATE...ALMOST ALL OF THE CWA WILL SEE SOME RAIN/THUNDERSTORMS
ALONG THE COLD FRONT AS IT MOVES THROUGH. DID NOT GO CRAZY WITH
THE POPS YET BECAUSE THE GFS CONTINUES TO INDICATE THAT THE UPPER
LOW WILL REMAIN SIGNIFICANTLY FURTHER NORTH...REDUCING
PRECIPITATION CHANCES ALONG THE FRONT. WENT AHEAD WITH 40 POPS
ALONG AND BEHIND THE FRONT WITH THIS FORECAST...BUT POPS MAY NEED
TO BE MUCH HIGHER IF THE CMC/ECMWF TRACK VERIFIES. ITS TOO EARLY
TO DETERMINE SEVERE WEATHER CHANCES...HOWEVER A LARGE OUTBREAK
DOES NOT LOOK LIKELY BECAUSE THE FRONT IS EXPECTED TO MOVE SOUTH
VERY QUICKLY WEDNESDAY AFTERNOON UNDERCUTTING MOST ORGANIZED
CONVECTION THAT INITIATES JUST OUT AHEAD OF THE FRONT.
EXTENDED...THE ECMWF INDICATES THAT A BIG BLOCKING PATTERN SETS
UP AFTER THE UPPER LOW MOVES INTO THE PLAINS FOR THE END OF THE
WEEK. THIS KEEPS THE UPPER LOW IN PLACE OVER THE CENTRAL PLAINS
THRU AT LEAST MAY 5TH...WHICH WOULD TEND TO KEEP TEMPERATURES
BELOW NORMAL OVER MOST OF THE CENTRAL AND SOUTHERN PLAINS THRU THE
FIRST WEEK OF MAY. THE COLDEST TEMPERATURES WOULD BE RIGHT AFTER
THE COLD FRONT...WITH TEMPERATURES MODERATING THEREAFTER AS THE
UPPER LOW DRIFTS NORTH OF THE CWA. CONFIDENCE IN THIS SOLUTION IS
NOT GREAT...HOWEVER MOST GUIDANCE INDICATES SOME SORT OF BLOCKING
PATTERN FOR LATE IN THE WEEK INTO NEXT WEEKEND...SO THE MAIN
FORECAST CONCERN IS WHERE WILL THE UPPER LOW BE WHEN THE BLOCKING
PATTERN SETS UP. AT THIS TIME KEPT TEMPERATURES BELOW NORMAL
DURING THIS PERIOD AS THERE IS NO GUIDANCE THAT SHOWS WE GET STUCK
IN A BLOCKING PATTERN WITH UPPER LEVEL RIDGING OVER THE PLAINS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 56 81 59 86 62 / 5 5 0 0 0
WACO, TX 60 81 57 85 60 / 30 10 0 0 0
PARIS, TX 52 79 52 82 57 / 5 5 0 0 0
DENTON, TX 53 81 55 86 59 / 5 5 0 0 0
MCKINNEY, TX 53 80 56 85 60 / 5 5 0 0 0
DALLAS, TX 56 83 61 86 65 / 10 5 0 0 0
TERRELL, TX 54 81 55 84 59 / 10 5 0 0 0
CORSICANA, TX 59 81 58 83 60 / 20 5 0 0 0
TEMPLE, TX 62 80 58 84 59 / 40 20 0 0 0
MINERAL WELLS, TX 54 83 56 85 59 / 5 5 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/58
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1233 PM CDT SAT APR 27 2013
.AVIATION...
STRATUS BURNING OFF FROM WEST...AND TIMING THE WESTERN EDGE INTO
METROPLEX GIVES VFR CONDITIONS BY 19Z. WACO CURRENTLY CLEAR...BUT
SATELLITE SHOWS SCT VFR CU FAIRLY CLOSE.
METROPLEX EXPECTED TO REMAIN CLEAR THROUGH END OF TAF CYCLE AND
BEYOND...BUT CONVECTION EXPECTED TO DEVELOP SOUTH OF WACO AND
ANVIL SHIELD WILL LIKELY GROW NORTH LATER TODAY THROUGH MOST OF
THE NIGHT. THERE REMAINS A LOW THREAT OF THUNDER/SHOWERS
OVERNIGHT...BUT BASED ON HI RES GUIDANCE FEEL THAT RAIN WILL STAY
SOUTH OF THE WACO AIRPORT.
SOUTH FLOW RETURNS TOMORROW. 84
&&
.UPDATE...
A COLD FRONT EXTENDED FROM JUST WEST OF PARIS TO SOUTHEAST OF
GREENVILLE...TERRELL...WEST...GATESVILLE AND LAMPASAS AT 16Z.
THIS FRONT WILL MOVE THROUGH WACO IN THE NEXT HALF HOUR...BUT
STALL OUT OVER THE SOUTHEASTERN PART OF THE FORECAST AREA THIS
AFTERNOON. HAVE ADJUSTED THE HOURLY WIND/TEMPERATURE/DEW POINT
GRIDS BASED ON THE LATEST RUC GUIDANCE WHICH SEEMS TO BE IN LINE
WITH ONGOING TRENDS.
THE 06Z TEXAS TECH WRF AND THE LATEST /12Z/ HIGH RESOLUTION RAPID
REFRESH...INDICATE THAT MOST OF THE SHOWERS AND THUNDERSTORMS
WILL BE TO THE SOUTH OF THE FORECAST AREA THIS AFTERNOON WITH A
LITTLE MORE MOVING INTO THE SOUTHEASTERN ZONES AFTER 23Z. FOR
NOW...HAVE LEFT POPS AS IS...BUT WE MAY BE ABLE TO TRIM A LITTLE
OFF LATER THIS AFTERNOON DEPENDING ON EXACTLY WHERE THE FRONT
STALLS.
58
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 27 2013/
EARLY MORNING WATER VAPOR IMAGERY DEPICTED A CYCLONIC CIRCULATION
CENTERED OVER SOUTH CENTRAL KS OR NORTH CENTRAL OK MOVING EAST.
THIS CIRCULATION WAS LOCATED ON THE EAST END OF A POSITIVELY
TILTED CYCLONIC SHEAR AXIS EXTENDING WSW OVER THE TX PANHANDLE AND
OVER WEST CENTRAL AZ. TO THE EAST OF THE KS/OK UPPER LOW WAS A
LINE OF LOOSELY ORGANIZED THUNDERSTORMS LOCATED FROM NORTHWESTERN
AR SOUTHWEST TO SOUTHEAST OK. 08Z /3AM/ SURFACE OBSERVATIONS
DEPICTED A COLD FRONT LOCATED NEAR A BOWIE TO PK LAKE TO COMANCHE
LINE MOVING SOUTHEAST. THE FWD 00Z RAOB INDICATED A SUBSTANTIAL
CAP IN PLACE OVER NORTH TX...AND THIS CAP WAS LIKELY RESPONSIBLE
FOR THE DEARTH OF PRECIPITATION ALONG THE PORTION OF THE FRONT IN
TEXAS EARLY THIS MORNING.
TODAY AND TONIGHT...GUIDANCE CONSISTENTLY INDICATES THAT THE
CYCLONIC CIRCULATION/UPPER LOW OVER THE KS/OK BORDER EARLY THIS
MORNING WILL DEEPEN INTO A CLOSED LOW WHILE MOVING EAST OVER THE
NEXT 24 HRS. THIS WILL CAUSE THE CYCLONIC SHEAR AXIS TO SWING
SOUTHEAST IN ITS WAKE OVER THE CWA LATE THIS AFTERNOON THROUGH THE
OVERNIGHT HRS. THE EVOLUTION OF THIS UPPER LEVEL SYSTEM WILL HAVE
SOME INTERESTING IMPACTS ON SURFACE FEATURES ACROSS NORTH AND
CENTRAL TX TODAY.
THE SURFACE LOW THAT WAS LOCATED JUST EAST OF WICHITA FALLS AT THE
TIME OF THIS DISCUSSION IS EXPECTED TO MOVE EAST NORTHEAST WITH
THE MAIN UPPER LOW OVER THE NEXT 24 HRS. THIS WILL CAUSE THE COLD
FRONT TO CONTINUE SOUTH ACROSS THE CWA THROUGH THIS AFTERNOON. AS
THE SURFACE LOW IS MOVING EAST ACROSS AR TODAY ANOTHER SURFACE LOW
IS EXPECTED TO DEVELOP OVER NORTHERN MEXICO TO THE WEST OF DEL RIO
IN RESPONSE TO THE CYCLONIC SHEAR AXIS MOVING SOUTHEAST. WITH A
NEW SURFACE LOW DEVELOPING TO THE SOUTHWEST...AND THE OTHER
SURFACE LOW MOVING OFF TO THE EAST...THE COLD FRONT WILL LIKELY
STALL OUT NEAR OR JUST SOUTHEAST OF A LINE FROM ATHENS TO WACO BY
THE MID-AFTERNOON HOURS.
OVERNIGHT MODELS ARE STILL NOT IN COMPLETE AGREEMENT AS TO WHERE
THE FRONT WILL COME TO A REST...BUT SOMEWHERE BETWEEN WACO AND
COLLEGE STATION IS THE CONSENSUS LOCATION. WHEREVER THE FRONT
STALLS...WITH LOW PRESSURE OFF TO THE NORTHEAST AND
SOUTHWEST...THE GENERAL LOW LEVEL WIND FIELD LOOKS TO BE
DOMINATED BY VERY WEAK DEFORMATION ON EITHER SIDE OF THE STALLED
FRONT THIS AFTERNOON. WEAK NORTHEAST WINDS NORTH OF THE FRONT AND
WEAK SOUTHWEST WINDS TO THE SOUTH WILL ACTUALLY MINIMIZE PURE
CONVERGENCE ALONG THE FRONT...MAKING IT VERY DIFFICULT TO
DETERMINE IF THE FRONT WILL BE AN IMPORTANT SOURCE OF LIFT THIS
AFTERNOON.
TEMPERATURES WILL GENERALLY BE WARMER SOUTHEAST OF THE
FRONT...BUT THE GULF MOISTURE IN PLACE WILL ACTUALLY SUPPORT
CLOUDIER CONDITIONS TO THE SOUTHEAST OF THE FRONT THIS AFTERNOON.
DRIER AIR TO THE NORTH COMBINED WITH SUBSIDENCE IN THE WAKE OF THE
DEPARTING UPPER LOW WILL CAUSE SKIES TO CLEAR OUT NORTH OF THE
FRONT. AFTERNOON SUNSHINE WILL WEAKEN THE TEMPERATURE GRADIENT
ALONG THE FRONT...REDUCING FRONTOGENETIC FORCING DURING THE PEAK
HEATING HRS OF THE DAY. AS A RESULT THINK MESOSCALE FORCING FOR
ASCENT ALONG THE FRONT WILL BE FAIRLY WEAK THIS AFTERNOON...
REDUCING CONFIDENCE IN CONVECTION INITIATION ALONG THE STALLED OUT
FRONT DURING THE PEAK HEATING HRS OF THE DAY.
AS A RESULT...BUMPED POPS DOWN A LITTLE BIT THRU SUNSET FOR
LOCATIONS ALONG AND SOUTH OF A LINE FROM COMANCHE TO CANTON.
GUIDANCE CONTINUES TO INDICATE THAT THERE WILL BE OVER 2000 J/KG
OF CAPE AVAILABLE FOR FREE CONVECTION IF STORMS CAN DEVELOP ALONG
THE FRONT. THEREFORE DESPITE THE LOW POPS...WILL CONTINUE TO
MENTION A CHANCE OF STRONG TO SEVERE STORMS AS ANYTHING THAT DOES
MANAGE TO DEVELOP WILL LIKELY BE QUITE STRONG THIS AFTERNOON.
DAMAGING WINDS AND LARGE HAIL WOULD BE THE MOST LIKELY HAZARDS IF
ANYTHING WERE ABLE TO DEVELOP ALONG THE FRONT THRU SUNSET.
TONIGHT...THE DRIER AIR TO THE NORTH WILL ACTUALLY HELP INCREASE
THE THERMAL GRADIENT ALONG THE STALLED OUT FRONT AS THIS AIR WILL
COOL MORE QUICKLY THAN THE CLOUDY AND MORE MOIST AIRMASS TO THE
SOUTH OF THE FRONT. AS A RESULT...EVEN THOUGH THIS SEEMS
COUNTER-INTUITIVE...OUR BEST CHANCES FOR STORMS ALONG THE FRONT MAY
BE WELL AFTER SUNSET TONIGHT. MODELS DO NOT REALLY INDICATE A BIG
INCREASE IN CONVERGENCE ALONG THE FRONT...BUT THE INCREASE IN THE
THERMAL GRADIENT WILL LEAD TO STRONGER MESOSCALE FORCING FOR
ASCENT. THIS COMBINED WITH THE MEAGER LARGE SCALE SUPPORT OFFERED
BY THE CYCLONIC SHEAR AXIS MOVING OVER THE REGION HAS CONFIDENCE A
BIT HIGHER IN STORMS ALONG THE FRONT AFTER SUNSET. AS A RESULT
WENT AHEAD AND BUMPED UP POPS FROM 00-12Z ALONG THE FRONT FOR
TONIGHT. SEVERE WEATHER CHANCES WILL NOT BE AS GREAT AFTER
SUNSET...HOWEVER LARGE HAIL IS STILL A POSSIBILITY WITH THE
STRONGEST STORMS. ANY STORMS THAT DEVELOP WILL LIKELY MOVE
PARALLEL TO THE FRONT...SO THERE IS A RISK FOR LOCALLY HEAVY
RAINFALL DUE TO THE POTENTIAL FOR STORMS TO TRAIN ALONG THE FRONT
TONIGHT. THAT SAID...POPS ARE ONLY IN THE 30 TO 40 PERCENT CHANCE
RANGE...SO IT IS STILL POSSIBLE THAT FORCING REMAINS TOO WEAK FOR
ANYTHING ALONG THE FRONT OVERNIGHT.
SUNDAY THROUGH TUESDAY...GUIDANCE INDICATES THAT WEAK UPPER LEVEL
RIDGING WILL BUILD OVER THE NORTHERN PORTIONS OF THE SOUTH PLAINS
DURING THE PERIOD WHICH SHOULD HELP KEEP US DRY. THE ECMWF
STUBBORNLY INDICATES THAT THE TAILING END OF THE CYCLONIC SHEAR
AXIS MOVING SOUTH OVER TX TONIGHT WILL BECOME ISOLATED FROM THE
DEPARTING UPPER LOW/SHEAR AXIS AND FORM A WEAK CUT-OFF UPPER LOW
OVER THE TX GULF COAST DURING THIS PERIOD. BASED ON THE ECMWFS
EVOLUTION AND TRACK OF THIS FEATURE...IT IS SOMEWHAT
INCONSEQUENTIAL TO NORTH AND CENTRAL TX AS WE WOULD REMAIN NORTH
OR NORTHWEST OF THIS UPPER LOW THRU THE PERIOD. THE ECMWF HAS BEEN
CONSISTENT WITH THIS FEATURE...SO CONFIDENCE IS HIGHER THAT IT
WILL DEVELOP...HOWEVER THIS SHOULD JUST REINFORCE RIDGING OVER THE
CWA INCREASING CONFIDENCE IN A DRY FORECAST FROM SUNDAY AFTERNOON
THRU TUESDAY. EVEN IF THE UPPER LOW DEVELOPS...IT IS EXPECTED TO
REMAIN TOO WEAK TO HAVE A LARGE IMPACT ON THE SURFACE PRESSURE
PATTERN...THEREFORE WE SHOULD REMAIN IN SOUTHERLY FLOW DUE TO LEE
SIDE TROUGHING IN RESPONSE TO A POWERFUL UPPER LOW EXPECTED TO
SWING INTO THE PLAINS MID-WEEK. SOUTH WINDS AND SUBSIDENCE ALOFT
SHOULD HELP US BRING TEMPERATURES UP INTO THE 80S DURING THIS
PERIOD.
MID-WEEK...MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE ON THE
EXACT EVOLUTION OF THE POWERFUL SYSTEM PROGGED TO MOVE OVER THE
PLAINS WEDNESDAY OR WEDNESDAY NIGHT. ASIDE FROM THE FAIRLY LARGE
PLACEMENT DISCREPANCIES BETWEEN THE GFS AND CANADIAN/ECMWF ALL
GUIDANCE AGREES THAT THIS UPPER LEVEL SYSTEM WILL BE UNSEASONABLY
STRONG AND MAY LEAD TO AN EXTENDED PERIOD OF BELOW NORMAL
TEMPERATURES FOR NORTH TX FOR THE FIRST SEVERAL DAYS OF MAY. THIS
FORECAST IS MOST IN LINE WITH THE CONSENSUS OF THE ECMWF/CANADIAN
OPERATIONAL MODELS THAT WERE VALID AT 27/00Z. THESE MODELS BRING
THE INITIAL UPPER LEVEL LOW OVER THE SOUTH PLAINS DRIVING A STRONG
COLD FRONT SOUTH ACROSS NORTH TX LATE WEDNESDAY AFTERNOON THRU THE
OVERNIGHT HRS.
ASSUMING THE UPPER LOW DIGS AS FAR SOUTH AS THESE MODELS
INDICATE...ALMOST ALL OF THE CWA WILL SEE SOME RAIN/THUNDERSTORMS
ALONG THE COLD FRONT AS IT MOVES THROUGH. DID NOT GO CRAZY WITH
THE POPS YET BECAUSE THE GFS CONTINUES TO INDICATE THAT THE UPPER
LOW WILL REMAIN SIGNIFICANTLY FURTHER NORTH...REDUCING
PRECIPITATION CHANCES ALONG THE FRONT. WENT AHEAD WITH 40 POPS
ALONG AND BEHIND THE FRONT WITH THIS FORECAST...BUT POPS MAY NEED
TO BE MUCH HIGHER IF THE CMC/ECMWF TRACK VERIFIES. ITS TOO EARLY
TO DETERMINE SEVERE WEATHER CHANCES...HOWEVER A LARGE OUTBREAK
DOES NOT LOOK LIKELY BECAUSE THE FRONT IS EXPECTED TO MOVE SOUTH
VERY QUICKLY WEDNESDAY AFTERNOON UNDERCUTTING MOST ORGANIZED
CONVECTION THAT INITIATES JUST OUT AHEAD OF THE FRONT.
EXTENDED...THE ECMWF INDICATES THAT A BIG BLOCKING PATTERN SETS
UP AFTER THE UPPER LOW MOVES INTO THE PLAINS FOR THE END OF THE
WEEK. THIS KEEPS THE UPPER LOW IN PLACE OVER THE CENTRAL PLAINS
THRU AT LEAST MAY 5TH...WHICH WOULD TEND TO KEEP TEMPERATURES
BELOW NORMAL OVER MOST OF THE CENTRAL AND SOUTHERN PLAINS THRU THE
FIRST WEEK OF MAY. THE COLDEST TEMPERATURES WOULD BE RIGHT AFTER
THE COLD FRONT...WITH TEMPERATURES MODERATING THEREAFTER AS THE
UPPER LOW DRIFTS NORTH OF THE CWA. CONFIDENCE IN THIS SOLUTION IS
NOT GREAT...HOWEVER MOST GUIDANCE INDICATES SOME SORT OF BLOCKING
PATTERN FOR LATE IN THE WEEK INTO NEXT WEEKEND...SO THE MAIN
FORECAST CONCERN IS WHERE WILL THE UPPER LOW BE WHEN THE BLOCKING
PATTERN SETS UP. AT THIS TIME KEPT TEMPERATURES BELOW NORMAL
DURING THIS PERIOD AS THERE IS NO GUIDANCE THAT SHOWS WE GET STUCK
IN A BLOCKING PATTERN WITH UPPER LEVEL RIDGING OVER THE PLAINS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 56 81 59 86 / 10 5 5 0 0
WACO, TX 83 60 81 57 85 / 20 30 10 0 0
PARIS, TX 78 52 79 52 82 / 10 5 5 0 0
DENTON, TX 77 53 81 55 86 / 10 5 5 0 0
MCKINNEY, TX 77 53 80 56 85 / 10 5 5 0 0
DALLAS, TX 80 56 83 61 86 / 10 10 5 0 0
TERRELL, TX 80 54 81 55 84 / 20 10 5 0 0
CORSICANA, TX 83 59 81 58 83 / 20 20 5 0 0
TEMPLE, TX 84 62 80 58 84 / 30 40 20 0 0
MINERAL WELLS, TX 80 54 83 56 85 / 10 5 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1228 PM CDT SAT APR 27 2013
.AVIATION...
THE PRIMARY CHALLENGE FOR THIS FORECAST PERIOD WILL BE THE TIMING
OF THUNDERSTORMS FOR THIS EVENING INTO EARLY TONIGHT. A WEAK
FRONTAL BOUNDARY IS CURRENTLY MOVING SLOWLY SOUTH ACROSS NORTHERN
PORTIONS OF THE HILL COUNTRY AND WILL CONTINUE TO MOVE SLOWLY
SOUTH THIS AFTERNOON AND THEN BECOME STATIONARY NEAR HIGHWAY 90
THIS EVENING WHILE AN UPPER LEVEL IMPULSE MOVES EASTWARD OUT OF
NORTHERN MEXICO. THIS FRONTAL BOUNDARY AND THE SIERRA MADRE IN
MEXICO WILL BE THE FOCUS AREAS OF CONVECTIVE DEVELOPMENT. THE
UPPER LEVEL DISTURBANCE WILL HELP IN THE PROPAGATION OF CONVECTION
TO THE EAST AND SOUTHEAST OVERNIGHT. CONTINUE TO LIKE THE 00Z ARW
AND 12Z TTU 3KM WRF FOR THUNDERSTORMS TIMING AND WILL USE A BLEND
OF THE TWO. MVFR CIGS CONTINUE TO LIFT LATE THIS MORNING AND
SHOULD SEE VFR CONDITIONS BETWEEN 19Z-20Z. OVERNIGHT WILL SEE MVFR
CIGS DEVELOP 06Z-08Z THEN FALL TO IFR BY 11Z-12Z. SFC WINDS WILL
BE E TO SE AT 5 TO 10 KTS THIS AFTERNOON AND EAST AT 5 TO 8 KTS
OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1046 AM CDT SAT APR 27 2013/
UPDATE...
TO EXTEND SLIGHT RISK OF SEVERE THUNDERSTORMS AND REMOVE MORNING DRIZZLE.
DISCUSSION...
THE MORNING UPDATE FROM SPC EXTENDED THE SLIGHT RISK AREA TO COVER
ALL OF SOUTH CENTRAL TEXAS. EXPECTING CONVECTION TO DEVELOP OVER
THE MEXICAN MOUNTAINS AND ALONG A COLD FRONT LATER THIS EVENING.
THE COLD FRONT IS CURRENTLY LYING JUST NORTH OF OUR NORTHERN CWA
BORDER FROM AROUND LAMPASAS TO SONORA TO SANDERSON. THIS FRONT
WILL DRIFT SOUTHWARD THROUGH THE AFTERNOON AND WILL LIKELY BE THE
FOCUS FOR THUNDERSTORMS. DEW POINTS SOUTH OF THE FRONT ARE IN THE
MID TO UPPER 60S. CLOUD COVER WILL KEEP TEMPERATURES DOWN UNTIL
AFTERNOON AND LIMITING INSTABILITY IN THE BOUNDARY LAYER. FORECAST
SOUNDINGS SHOW CAPE RISING TO 1500-2000 J/KG LATER TODAY. STILL
DISAGREEMENT ON TIMING. GFS IS LATER TO DEVELOP STRONG INSTABILITY
AND THIS SEEMS MORE LIKELY WITH LATER EROSION OF CLOUD DECK.
OUR FORECAST LOOKS TO BE IN GOOD SHAPE WITH MOST CONVECTION AFTER
00Z. HAVE REMOVED MENTION OF MORNING DRIZZLE. DRIZZLE OR SPRINKLES
MAY STILL OCCUR...BUT WILL BE ISOLATED AND NOT WORTH KEEPING IN
FORECAST. HAVE ALSO MADE MINOR ADJUSTMENTS TO HOURLY GRIDS TO
ACCOUNT FOR OBSERVATIONAL TRENDS.
PREV DISCUSSION... /ISSUED 631 AM CDT SAT APR 27 2013/
DISCUSSION...
SEE AVIATION FOR THE 12Z TAF DISCUSSION.
AVIATION...
THE PRIMARY CHALLENGE FOR THIS TAF PACKAGE IS THE TIMING OF THUNDERSTORMS
FOR THIS EVENING INTO EARLY TONIGHT. A WEAK FRONTAL BOUNDARY WILL FILTER
SOUTHWARD ACROSS THE HILL COUNTRY THIS EVENING BECOMING STATIONARY IN
THE VICINITY OF HIGHWAY 90 WHILE AN UPPER LEVEL IMPULSE MOVES EASTWARD
OUT OF MEXICO. THE FRONTAL BOUNDARY AND THE EASTERN SLOPES OF THE SIERRA
MADRE WILL BE THE FOCUS AREAS OF CONVECTIVE DEVELOPMENT. THE UPPER LEVEL
DISTURBANCE WILL HELP IN THE PROPAGATION OF CONVECTION TO THE EAST AND
SOUTHEAST OVERNIGHT. A BLEND OF THE 00Z ARW...07Z RUC13 AND 00Z TTU
3KM WRF WILL BE USED FOR TIMING OF THUNDERSTORMS IMPACTING THE TAF
SITES. OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING IMPROVING TO VFR
THIS AFTERNOON. CIGS WILL ONCE AGAIN LOWER TO MVFR AFTER 06Z...IFR BY
11Z. SFC WINDS TODAY S TO SE AT 5 TO 10 KTS...BACKING TO THE EAST AT
5 TO 8 KTS OVERNIGHT BECOMING L/V BY SUNDAY MORNING.
PREV DISCUSSION... /ISSUED 325 AM CDT SAT APR 27 2013/
SHORT TERM (TODAY THROUGH SUNDAY)...
INCREASING CHANCES FOR RAIN THIS WEEKEND AS A COLD FRONT SLIDES INTO
THE REGION. FOR TODAY...A CONTINUED SOUTHEAST INFLUX OF LOW LEVEL
MOISTURE WILL KEEP THE AREA POTENTIALLY UNSTABLE AS BOUNDARIES
APPROACH THE AREA. A MIXED LAYER CAP ALOFT WILL KEEP MUCH
CONVECTION FROM FIRING UNTIL AFTER DARK WHEN LOW LEVEL CONVERGENT
FORCES TAKE OVER (ALONG WITH SUPPORT ALOFT FROM A MID LEVEL JET).
HIGHS TODAY WILL BE IN THE 80S. WILL PLACE AT LEAST A SLIGHT
CHANCE OF THUNDERSTORMS OVER OUR NORTHERN CWA ALONG THE FRONT FOR
THIS AFTERNOON. THE COLD FRONT...LOCATED EARLY THIS MORNING OVER
THE TEXAS SOUTH PLAINS WILL SLIP SOUTH INTO OUR NORTHERN CWA BY
AFTERNOON. THE GFS MODEL SOLUTION STALLS THE FRONT OVER OVER
NORTHERN CWA DURING THE EVENING...THEN EDGES IT SOUTHWARD INTO THE
CENTRAL CWA OVERNIGHT. THIS IS SIGNIFICANT IN AS FAR AS RAINFALL
AND POTENTIALLY SEVERE WEATHER ARE CONCERNED AS BURRO MOUNTAIN
(MEXICAN PLATEAU) STORMS WHICH DEVELOP DURING THE LATE AFTERNOON/
EVENING HOURS PUSH EASTWARD AND INTERSECT THE FRONT DURING THE
OVERNIGHT HOURS OVER WESTERN SECTIONS. MOIST LOW LEVEL SOUTHEAST
FLOW (DEWPOINTS IN UPPER 60S) WILL MAINTAIN THESE STORMS AS THEY
TRAVERSE EAST...INTERSECTING THE FRONT AND ENHANCING RAIN AMOUNTS
AND SEVERITY OF STORMS. WILL INCLUDE A CHANCE OF SOME OF THE
STORMS BECOMING SEVERE TONIGHT OVER THE WESTERN HALF OF THE CWA
WITH THE GREATEST THREAT BEING FROM LARGE HAIL. SOME DAMAGING
WIND GUSTS ARE ALSO POSSIBLE. ISOLATED RAIN AMOUNTS OF 1 TO 3
INCHES ARE EXPECTED ALONG THE TRACK OF THE BURRO STORMS AS THEY
INTERSECT THE FRONT OVER WESTERN SECTIONS TONIGHT. SOME
STABILIZATION IS EXPECTED SUNDAY AS THE FRONT AND RAIN-COOLED AIR
SETTLE OVER THE AREA. HOWEVER THERE REMAINS ENOUGH DYNAMICS AND
INSTABILITY ALOFT FOR SOME RE-DEVELOPMENT OF STORMS IN DAYTIME
HEATING. HIGHS SUNDAY IN THE UPPER 70S HILLS...NEAR 80 TO LOW 80S
ELSEWHERE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
AS FRONTOLYSIS (DISSIPATION OR WEAKENING OF A FRONT) OCCURS SUNDAY
NIGHT...SOUTHEAST FLOW AND LIFT OVER THE WEAKENING BOUNDARY MAY BE
ENOUGH FOR ADDITIONAL CONVECTION. IN FACT...ANOTHER THREAT FOR
BURRO DEVELOPMENT MAY OCCUR OVERNIGHT SUNDAY/EARLY MONDAY MORNING
AS MOIST SOUTHEAST FLOW UPLIFTS ACROSS THE MEXICAN PLATEAU AMID A
WEAK UPPER LEVEL SUBTROPICAL JET. THIS INSTABILITY AND UNSETTLED
WEATHER PATTERN WILL LINGER THROUGH TUESDAY AS A MOIST SOUTHEAST
FLOW AT THE SURFACE AND COOLING ALOFT COUPLED WITH DISTURBANCES
TRIGGER FURTHER ACTIVITY ESPECIALLY OVER SOUTHWEST PORTIONS OF THE
CWA. THE UPPER TROUGH WILL EXIT THE REGION WEDNESDAY WITH A STABLE
NORTHERLY FLOW ALOFT IN PLACE. A STRONG COLD FRONT WILL THEN PUSH
RAPIDLY THROUGH THE REGION WEDNESDAY NIGHT WITH LOW CHANCES OF
SHOWERS AND THUNDERSTORMS LINING THE FRONT. DECREASING CLOUDINESS
AND MUCH COOLER THURSDAY WITH HIGHS GENERALLY IN THE 70S. SURFACE
RIDGING WILL SETTLE OVER THE AREA THURSDAY NIGHT AND EARLY FRIDAY
WITH LOWS FRIDAY MORNING MOSTLY IN THE 40S. MOSTLY SUNNY FRIDAY
WITH HIGHS IN THE 70S.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 84 62 83 60 84 / 10 50 30 10 10
AUSTIN BERGSTROM INTL AIRPORT 84 61 82 57 83 / 10 50 30 20 10
NEW BRAUNFELS MUNI AIRPORT 85 61 83 58 83 / 10 60 40 20 20
BURNET MUNI AIRPORT 83 60 81 57 83 / 20 50 20 10 10
DEL RIO INTL AIRPORT 85 66 81 64 84 / 10 60 40 30 20
GEORGETOWN MUNI AIRPORT 82 61 81 58 82 / 20 50 20 10 10
HONDO MUNI AIRPORT 84 63 81 60 83 / 10 70 40 30 20
SAN MARCOS MUNI AIRPORT 83 62 82 58 82 / 10 50 30 20 20
LA GRANGE - FAYETTE REGIONAL 85 66 83 62 84 / 20 40 30 10 20
SAN ANTONIO INTL AIRPORT 83 63 81 60 82 / 10 60 40 30 20
STINSON MUNI AIRPORT 84 63 81 61 82 / 10 60 40 30 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...10
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1227 PM CDT SAT APR 27 2013
.DISCUSSION...
SEE 18Z AVIATION DISCUSSION.
&&
.AVIATION...
4KM WRF IS VERY AGGRESSIVE WITH CONVECTIVE POTENTIAL THIS AFTN
WHICH IS OF SOME CONCERN. OTHER SHORT TERM MODELS ARE LESS BULLISH
WITH THUNDER. A S/WV WILL MOVE TOWARD SE TX THIS AFTN AND THIS
FEATURE COUPLED WITH HIGH PW VALUES...SOME UPPER LEVEL DIVERGENCE
SHOULD YIELD HIGH RAIN CHANCES FOR THIS AFTN AND EVENING. WILL
CARRY VCSH FOR THE AFTN AND EVENING. THE NAM AND RAP HAVE
INITIALIZED BEST SO HAVE LEANED TOWARD THOSE SOLUTIONS AND THIS
KEEPS MOST OF THE ORGANIZED PRECIP AND THUNDER NORTH OF THE
HOUSTON TERMINALS. AM EXPECTING SOME FOG AND IFR/LIFR CIGS TO
DEVELOP AFTER 08Z AREA WIDE. 43
&&
.PREV DISCUSSION... /ISSUED 1058 AM CDT SAT APR 27 2013/
UPDATE...
ELEMENTS ARE BEGINNING TO LINE UP THAT LEAN TOWARDS A HIGHER
CHANCE FOR MORE WIDESPREAD AFTERNOON RAIN AND THUNDER. RECENT
MODELS ARE COMING IN MORE WET...WITH BETTER MID TO UPPER LEVEL
DYNAMICS OVER EASTERN TEXAS WITHIN THE NEXT 24 HOURS. AT THE
SURFACE...AN APPROACHING BOUNDARY NOW NESTLING OVER CENTRAL TEXAS
MAY SAG INTO OUR EXTREME NORTHERN CWA TO PROVIDE BETTER LOW LEVEL
FOCUS AS EARLY PM TEMPERATURES WARM INTO THE UPPER 70S. MOISTURE
IS NOT A PROBLEM WITH PWAT VALUES IN THE 75 PERCENTILE RANGE FOR
LATE APRIL. SHORT TERM MODELS (RAP AND NAM) MAY BE ONTO SOMETHING
AS LOCAL TERMINAL DOPPLERS ARE DISPLAYING INCREASING -SHRA COVERAGE
OVER THE PAST HOUR OR TWO. PROG SOUNDINGS DO ERODE THIS MORNING`S
9-7H CAP...WITH SOME 12Z JET LEVEL DIVERGENCE NOTED AT 3OO MB
(TEXAS LAYING BETWEEN SOUTHERN POLAR BRANCH AND STJ). COMBINE ALL
OF THESE CHARACTERISTICS WITH WHAT APPEARS TO BE A SHORTWAVE
DISTURBANCE WITHIN THE NORTHERN MEXICO JET STREAK AND YOU HAVE A
STRONGER CASE FOR INCREASING OVERALL (SHORT TERM) POPS. 31
PREV DISCUSSION... /ISSUED 642 AM CDT SAT APR 27 2013/
AVIATION...
WIDESPREAD MVFR CEILINGS AGAIN THIS MORNING WITH SOME PATCHES OF
IFR. WILL SEE CEILINGS GRADUALLY RISE LATER THIS MORNING. S/SE
WINDS WILL BE LIGHTER TODAY AS THE PRESSURE GRADIENT HAS WEAKENED.
THERE IS A BOUNDARY THAT WILL LIKELY SERVE TO FOCUS SCT SHWRS AND
TSTMS LATE THIS AFT/EVE ACROSS NORTHERN AREAS. ADDITIONAL SHWR/TSTM
ACTIVITY THAT DEVELOPS WEST OF THE AREA THIS EVENING MAY MOVE EAST
ACROSS CENTRAL PORTIONS OF THE AREA AFTER MIDNIGHT ON SUN. 33
PREV DISCUSSION... /ISSUED 446 AM CDT SAT APR 27 2013/
DISCUSSION...
ADDED MARINE DISCUSSION.
MARINE...
LIGHT TO MODERATE EAST TO SOUTHEAST WINDS WILL CONTINUE INTO THE
MIDDLE OF NEXT WEEK. SIGNIFICANT CHANGE CONCERNING WIND/SEAS WILL
NOT OCCUR UNTIL EARLY THURSDAY OF NEXT WEEK...WHEN AN UNSEASONABLY
STRONG COLD FRONT WILL MOVE ACROSS THE MARINE AREA. EARLY
THURSDAY`S FORECAST CURRENTLY ADVERTISES STRONG POST FRONTAL
NORTHERLY WINDS THAT COULD REACH GALE FORCE IN GUSTS...ESPECIALLY
ACROSS THE OFFSHORE WATERS. THERE IS A CHANCE OF SOME SHOWERS OR
THUNDERSTORMS MOVING OFFSHORE LATE SATURDAY NIGHT OR EARLY SUNDAY.
33
PREV DISCUSSION... /ISSUED 441 AM CDT SAT APR 27 2013/
DISCUSSION...
SFC ANALYSIS AT 09Z HAS SFC LOW IN C OK WITH A WEAK BOUNDARY
TRAILING BACK TO THE SW THROUGH W C TX INTO W TX. MAINLY SSE WINDS
ACROSS THE AREA WITH SFC DEWPOINTS IN THE UPPER 60S ALONG THE
COAST. GULF MOISTURE IS CONTRIBUTING TO LOW STRATOCU DECKS THIS
MORNING WHICH WILL KEEP MIN TEMPS FROM DROPPING TOO MUCH MORE FROM
CURRENT TEMPS. UPPER AIR ANALYSIS HAS UPPER LOW OVER S PLAINS WITH
A JET STREAK STRETCHING FROM W TX TO C TENN. SFC LOW SHOULD MOVE
EAST AS UPPER LOW SLOWLY MOVES TOWARDS MISS RIVER VALLEY. SFC
BOUNDARY SHOULD WORK INTO NORTHERN AREAS OF SE TX FROM BRAZOS
VALLEY TO THE PINEY WOODS. BOUNDARY SHOULD BE FOCUS FOR
THUNDERSTORM ACTIVITY LATER THIS EVENING AND INTO THE OVERNIGHT.
MAIN FORECAST CONCERN THE NEXT COUPLE OF DAYS WILL BE CONVECTION.
UPPER LEVEL SUPPORT BECOMES MORE FAVORABLE TONIGHT INTO SUN
MORNING AS RIGHT ENTRANCE OF THE JET MOVES OVER THE AREA WITH AN
ENHANCED SUB-TROPICAL JET PUSHING ACROSS THE RIO GRANDE AND S TX.
COMBINATION OF DIVERGENCE FROM JET CIRC AND DIFFLUENCE OF JETS MAY
PROVIDE ENOUGH LARGE SCALE ASCENT TO ERODE MID LEVEL CAP
INVERSION. GFS/NAM BUFR SOUNDINGS SEEM TO SUPPORT THIS IDEA AND
ALSO YEILD CAPE AROUND 1500-2500 J/KG FROM COLLEGE STATION TO
CROCKETT JUST SOUTH OF THE FRONTAL BOUNDARY. YET MODELS WAIT UNTIL
THE LATE EVENING AFTER 00Z FOR CONVECTION TO INITIATE. WILL KEEP
POPS AROUND 30 PERCENT IN THE EVENING AND THEN UP TO 40 PERCENT
FOR THE OVERNIGHT TIME FRAME. WRF-ARW SHOWS CONVECTION DEVELOPING
IN THE EVENING OVER THE HILL COUNTRY THAT MAY THEN MOVE INTO SE TX
BY 09-12Z SUN AND CONTINUE UNTIL 18Z. RIGHT NOW SPC DOES NOT HAVE
SE TX IN A SEVERE THUNDERSTORM OUTLOOK BUT THINK IF SFC BASED
CONVECTION DOES FORM WITH AFOREMENTIONED INSTABILITY...COULD SEE
SEVERE STORMS WITH HAIL/WIND THREAT. DEEP LAYER SHEAR AND UPPER
LEVEL JET MAY EVEN SUPPORT ORGANIZED STORM STRUCTURES WHICH WOULD
ALSO ENHANCE THE SEVERE THREAT. AT THIS TIME...JUST A WAITING GAME
TO SEE IF CAP WILL HOLD OR NOT.
FRONTAL BOUNDARY DOES WEAKEN/DISSIPATE MON/TUE SO WILL ONLY CARRY
A SLIGHT CHANCE OF STORMS FOR THIS TIME PERIOD. MOISTURE MAY
INCREASE ENOUGH TUE TO HAVE A FEW MORE SCT STORMS. ALSO LOOKS LIKE
LEFT OVER VORTICITY WILL REMAIN OVER SE TX THROUGH TUE WITH MAIN
UPPER LEVEL SHORT WAVE MOVING OUT OF THE AREA. A FAIRLY STRONG JET
AND UPPER LEVEL TROUGH ALSO DEVELOPS MON/TUE OVER THE INTER
MOUNTAIN WEST. BY WED A STRONG SHORTWAVE DROPS INTO THE ROCKIES
AND C PLAINS. THIS AMPLIFIED PATTERN HELPS SUPPORT A STRONG COLD
FRONT PUSHING INTO TX LATE WED AND WED NIGHT. GFS HAS BEEN QUITE
CONSISTENT WITH FRONTAL PASSAGE IN THE 06Z TO 12Z THUR TIME
FRAME. THE ECMWF HAS BEEN CONSISTENT WITH THIS TIMING BUT THE 00Z
RUNS HAVE BEEN SLOWER WITH THE FRONT. WILL KEEP 30 POPS FOR
CONVECTION ALONG THE FRONT AND POST FRONTAL PRECIP. DO EXPECT
CLEARING TO OCCUR THUR AFTERNOON AND NIGHT. BOTH GFS/ECMWF BRING A
1040MB HIGH INTO THE C AND N PLAINS BY 12Z THUR. SFC HIGH DOES
STRETCH OVER ALL OF THE PLAINS AND DOWN INTO THE GULF. SHOULD
WINDS DECREASE ENOUGH FRI MORNING LOW TEMPS WILL BE IN RECORD LOW
TERRITORY. WILL DROP MIN TEMP TO 48F FOR HOUSTON IAH WHICH IS ONE
DEGREE ABOVE THE RECORD OR COUPLE OF DEGREES BELOW GUIDANCE.
LATEST GFS ENSEMBLE MOS HAS A LOW MEMBER TEMP OF 45F FOR FRI
MORNING. GIVEN SOME MORE CONSISTENCY MAY NEED TO GO WITH A RECORD
LOW FORECAST TEMP. THUR/FRI NEXT WEEK WILL BE ON THE CHILLY SIDE.
NOT SURE HOW MUCH OF A WARM UP WILL OCCUR BEHIND THE FRONT. GFS
BRINGS 850MB TEMPS DOWN TO 2C BY FRI MORNING. GIVE STRONG COLD
ADVECTION...MAY BE TOUGH FOR TEMPS TO REACH THE 70S EACH DAY. THIS
WILL LARGELY DEPEND ON CLOUD COVER AND THE MAGNITUDE OF COLD
ADVECTION. REGARDLESS LOOKS LIKE TEMPS WILL BE A GOOD 10-15
DEGREES BELOW NORMAL FOR THE END OF NEXT WEEK.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 84 67 83 61 84 / 50 40 30 10 10
HOUSTON (IAH) 83 68 82 62 83 / 60 40 40 10 20
GALVESTON (GLS) 77 68 77 66 78 / 40 20 30 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1046 AM CDT SAT APR 27 2013
.UPDATE...
TO EXTEND SLIGHT RISK OF SEVERE THUNDERSTORMS AND REMOVE MORNING DRIZZLE.
&&
.DISCUSSION...
THE MORNING UPDATE FROM SPC EXTENDED THE SLIGHT RISK AREA TO COVER
ALL OF SOUTH CENTRAL TEXAS. EXPECTING CONVECTION TO DEVELOP OVER
THE MEXICAN MOUNTAINS AND ALONG A COLD FRONT LATER THIS EVENING.
THE COLD FRONT IS CURRENTLY LYING JUST NORTH OF OUR NORTHERN CWA
BORDER FROM AROUND LAMPASAS TO SONORA TO SANDERSON. THIS FRONT
WILL DRIFT SOUTHWARD THROUGH THE AFTERNOON AND WILL LIKELY BE THE
FOCUS FOR THUNDERSTORMS. DEW POINTS SOUTH OF THE FRONT ARE IN THE
MID TO UPPER 60S. CLOUD COVER WILL KEEP TEMPERATURES DOWN UNTIL
AFTERNOON AND LIMITING INSTABILITY IN THE BOUNDARY LAYER. FORECAST
SOUNDINGS SHOW CAPE RISING TO 1500-2000 J/KG LATER TODAY. STILL
DISAGREEMENT ON TIMING. GFS IS LATER TO DEVELOP STRONG INSTABILITY
AND THIS SEEMS MORE LIKELY WITH LATER EROSION OF CLOUD DECK.
OUR FORECAST LOOKS TO BE IN GOOD SHAPE WITH MOST CONVECTION AFTER
00Z. HAVE REMOVED MENTION OF MORNING DRIZZLE. DRIZZLE OR SPRINKLES
MAY STILL OCCUR...BUT WILL BE ISOLATED AND NOT WORTH KEEPING IN
FORECAST. HAVE ALSO MADE MINOR ADJUSTMENTS TO HOURLY GRIDS TO
ACCOUNT FOR OBSERVATIONAL TRENDS.
&&
.PREV DISCUSSION... /ISSUED 631 AM CDT SAT APR 27 2013/
DISCUSSION...
SEE AVIATION FOR THE 12Z TAF DISCUSSION.
AVIATION...
THE PRIMARY CHALLENGE FOR THIS TAF PACKAGE IS THE TIMING OF THUNDERSTORMS
FOR THIS EVENING INTO EARLY TONIGHT. A WEAK FRONTAL BOUNDARY WILL FILTER
SOUTHWARD ACROSS THE HILL COUNTRY THIS EVENING BECOMING STATIONARY IN
THE VICINITY OF HIGHWAY 90 WHILE AN UPPER LEVEL IMPULSE MOVES EASTWARD
OUT OF MEXICO. THE FRONTAL BOUNDARY AND THE EASTERN SLOPES OF THE SIERRA
MADRE WILL BE THE FOCUS AREAS OF CONVECTIVE DEVELOPMENT. THE UPPER LEVEL
DISTURBANCE WILL HELP IN THE PROPAGATION OF CONVECTION TO THE EAST AND
SOUTHEAST OVERNIGHT. A BLEND OF THE 00Z ARW...07Z RUC13 AND 00Z TTU
3KM WRF WILL BE USED FOR TIMING OF THUNDERSTORMS IMPACTING THE TAF
SITES. OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING IMPROVING TO VFR
THIS AFTERNOON. CIGS WILL ONCE AGAIN LOWER TO MVFR AFTER 06Z...IFR BY
11Z. SFC WINDS TODAY S TO SE AT 5 TO 10 KTS...BACKING TO THE EAST AT
5 TO 8 KTS OVERNIGHT BECOMING L/V BY SUNDAY MORNING.
PREV DISCUSSION... /ISSUED 325 AM CDT SAT APR 27 2013/
SHORT TERM (TODAY THROUGH SUNDAY)...
INCREASING CHANCES FOR RAIN THIS WEEKEND AS A COLD FRONT SLIDES INTO
THE REGION. FOR TODAY...A CONTINUED SOUTHEAST INFLUX OF LOW LEVEL
MOISTURE WILL KEEP THE AREA POTENTIALLY UNSTABLE AS BOUNDARIES
APPROACH THE AREA. A MIXED LAYER CAP ALOFT WILL KEEP MUCH
CONVECTION FROM FIRING UNTIL AFTER DARK WHEN LOW LEVEL CONVERGENT
FORCES TAKE OVER (ALONG WITH SUPPORT ALOFT FROM A MID LEVEL JET).
HIGHS TODAY WILL BE IN THE 80S. WILL PLACE AT LEAST A SLIGHT
CHANCE OF THUNDERSTORMS OVER OUR NORTHERN CWA ALONG THE FRONT FOR
THIS AFTERNOON. THE COLD FRONT...LOCATED EARLY THIS MORNING OVER
THE TEXAS SOUTH PLAINS WILL SLIP SOUTH INTO OUR NORTHERN CWA BY
AFTERNOON. THE GFS MODEL SOLUTION STALLS THE FRONT OVER OVER
NORTHERN CWA DURING THE EVENING...THEN EDGES IT SOUTHWARD INTO THE
CENTRAL CWA OVERNIGHT. THIS IS SIGNIFICANT IN AS FAR AS RAINFALL
AND POTENTIALLY SEVERE WEATHER ARE CONCERNED AS BURRO MOUNTAIN
(MEXICAN PLATEAU) STORMS WHICH DEVELOP DURING THE LATE AFTERNOON/
EVENING HOURS PUSH EASTWARD AND INTERSECT THE FRONT DURING THE
OVERNIGHT HOURS OVER WESTERN SECTIONS. MOIST LOW LEVEL SOUTHEAST
FLOW (DEWPOINTS IN UPPER 60S) WILL MAINTAIN THESE STORMS AS THEY
TRAVERSE EAST...INTERSECTING THE FRONT AND ENHANCING RAIN AMOUNTS
AND SEVERITY OF STORMS. WILL INCLUDE A CHANCE OF SOME OF THE
STORMS BECOMING SEVERE TONIGHT OVER THE WESTERN HALF OF THE CWA
.WITH THE GREATEST THREAT BEING FROM LARGE HAIL. SOME DAMAGING
WIND GUSTS ARE ALSO POSSIBLE. ISOLATED RAIN AMOUNTS OF 1 TO 3
INCHES ARE EXPECTED ALONG THE TRACK OF THE BURRO STORMS AS THEY
INTERSECT THE FRONT OVER WESTERN SECTIONS TONIGHT. SOME
STABILIZATION IS EXPECTED SUNDAY AS THE FRONT AND RAIN-COOLED AIR
SETTLE OVER THE AREA. HOWEVER THERE REMAINS ENOUGH DYNAMICS AND
INSTABILITY ALOFT FOR SOME RE-DEVELOPMENT OF STORMS IN DAYTIME
HEATING. HIGHS SUNDAY IN THE UPPER 70S HILLS...NEAR 80 TO LOW 80S
ELSEWHERE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
AS FRONTOLYSIS (DISSIPATION OR WEAKENING OF A FRONT) OCCURS SUNDAY
NIGHT...SOUTHEAST FLOW AND LIFT OVER THE WEAKENING BOUNDARY MAY BE
ENOUGH FOR ADDITIONAL CONVECTION. IN FACT...ANOTHER THREAT FOR
BURRO DEVELOPMENT MAY OCCUR OVERNIGHT SUNDAY/EARLY MONDAY MORNING
AS MOIST SOUTHEAST FLOW UPLIFTS ACROSS THE MEXICAN PLATEAU AMID A
WEAK UPPER LEVEL SUBTROPICAL JET. THIS INSTABILITY AND UNSETTLED
WEATHER PATTERN WILL LINGER THROUGH TUESDAY AS A MOIST SOUTHEAST
FLOW AT THE SURFACE AND COOLING ALOFT COUPLED WITH DISTURBANCES
TRIGGER FURTHER ACTIVITY ESPECIALLY OVER SOUTHWEST PORTIONS OF THE
CWA. THE UPPER TROUGH WILL EXIT THE REGION WEDNESDAY WITH A STABLE
NORTHERLY FLOW ALOFT IN PLACE. A STRONG COLD FRONT WILL THEN PUSH
RAPIDLY THROUGH THE REGION WEDNESDAY NIGHT WITH LOW CHANCES OF
SHOWERS AND THUNDERSTORMS LINING THE FRONT. DECREASING CLOUDINESS
AND MUCH COOLER THURSDAY WITH HIGHS GENERALLY IN THE 70S. SURFACE
RIDGING WILL SETTLE OVER THE AREA THURSDAY NIGHT AND EARLY FRIDAY
WITH LOWS FRIDAY MORNING MOSTLY IN THE 40S. MOSTLY SUNNY FRIDAY
WITH HIGHS IN THE 70S.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 84 62 83 60 84 / 10 50 30 10 10
AUSTIN BERGSTROM INTL AIRPORT 84 61 82 57 83 / 10 50 30 20 10
NEW BRAUNFELS MUNI AIRPORT 85 61 83 58 83 / 10 60 40 20 20
BURNET MUNI AIRPORT 83 60 81 57 83 / 20 50 20 10 10
DEL RIO INTL AIRPORT 85 66 81 64 84 / 10 60 40 30 20
GEORGETOWN MUNI AIRPORT 82 61 81 58 82 / 20 50 20 10 10
HONDO MUNI AIRPORT 84 63 81 60 83 / 10 70 40 30 20
SAN MARCOS MUNI AIRPORT 83 62 82 58 82 / 10 50 30 20 20
LA GRANGE - FAYETTE REGIONAL 85 66 83 62 84 / 20 40 30 10 20
SAN ANTONIO INTL AIRPORT 83 63 81 60 82 / 10 60 40 30 20
STINSON MUNI AIRPORT 84 63 81 61 82 / 10 60 40 30 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...10
SYNOPTIC/GRIDS...05
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION...CORRECTED
NWS FORT WORTH TX
1020 AM CDT SAT APR 27 2013
.UPDATE...
A COLD FRONT EXTENDED FROM JUST WEST OF PARIS TO SOUTHEAST OF
GREENVILLE...TERRELL...WEST...GATESVILLE AND LAMPASAS AT 16Z.
THIS FRONT WILL MOVE THROUGH WACO IN THE NEXT HALF HOUR...BUT
STALL OUT OVER THE SOUTHEASTERN PART OF THE FORECAST AREA THIS
AFTERNOON. HAVE ADJUSTED THE HOURLY WIND/TEMPERATURE/DEW POINT
GRIDS BASED ON THE LATEST RUC GUIDANCE WHICH SEEMS TO BE IN LINE
WITH ONGOING TRENDS.
THE 06Z TEXAS TECH WRF AND THE LATEST /12Z/ HIGH RESOLUTION RAPID
REFRESH...INDICATE THAT MOST OF THE SHOWERS AND THUNDERSTORMS
WILL BE TO THE SOUTH OF THE FORECAST AREA THIS AFTERNOON WITH A
LITTLE MORE MOVING INTO THE SOUTHEASTERN ZONES AFTER 23Z. FOR
NOW...HAVE LEFT POPS AS IS...BUT WE MAY BE ABLE TO TRIM A LITTLE
OFF LATER THIS AFTERNOON DEPENDING ON EXACTLY WHERE THE FRONT
STALLS.
58
&&
.AVIATION...
COLD FRONT IS KNOCKING ON THE METROPLEX/S DOOR THIS MORNING. FRONT
IS THROUGH ALLIANCE...AND WILL BE THROUGH THE OTHER 4 SITES IN THE
METRO WITHIN THE NEXT HOUR. LOW CLOUDS HAVE BEEN SCATTERED AHEAD
OF THE FRONT...BUT REMAIN IN PLACE NEAR WACO WHERE THE BEST LOW-
LEVEL MOISTURE IS LOCATED. LOW CLOUDS ARE EXPECTED TO FILL IN
BEHIND THE COLD FRONT. WILL START THE METRO TAF SITES OFF WITH A
NORTHWEST WIND AND LOW MVFR CIGS...EXCEPT KDAL AND KGKY WHERE THE
FROPA IS EXPECTED CLOSER TO 1230Z. CURRENT EXTRAPOLATION HAS THE
FRONT REACHING WACO AROUND 17Z...BEFORE STALLING SOUTH OF THE
AIRPORT. WILL KEEP MVFR IN THE TAFS UNTIL 17Z FOR THE METRO AND
21Z FOR WACO. THIS TIMING IS CLOSE TO WHAT THE LATEST RAP IS
SHOWING. LOW CLOUDS DO NOT EXTEND TOO FAR WEST...AND CLEARING
SHOULD OCCUR EARLIER THAN PREVIOUSLY EXPECTED. CANT RULE OUT A
SHOWER OR THUNDERSTORM CLOSER TO THE FRONT NEAR WACO THIS
AFTERNOON...BUT PROBABILITIES ARE TOO LOW TO MENTION IN THE TAF AT
THIS TIME.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 27 2013/
EARLY MORNING WATER VAPOR IMAGERY DEPICTED A CYCLONIC CIRCULATION
CENTERED OVER SOUTH CENTRAL KS OR NORTH CENTRAL OK MOVING EAST.
THIS CIRCULATION WAS LOCATED ON THE EAST END OF A POSITIVELY
TILTED CYCLONIC SHEAR AXIS EXTENDING WSW OVER THE TX PANHANDLE AND
OVER WEST CENTRAL AZ. TO THE EAST OF THE KS/OK UPPER LOW WAS A
LINE OF LOOSELY ORGANIZED THUNDERSTORMS LOCATED FROM NORTHWESTERN
AR SOUTHWEST TO SOUTHEAST OK. 08Z /3AM/ SURFACE OBSERVATIONS
DEPICTED A COLD FRONT LOCATED NEAR A BOWIE TO PK LAKE TO COMANCHE
LINE MOVING SOUTHEAST. THE FWD 00Z RAOB INDICATED A SUBSTANTIAL
CAP IN PLACE OVER NORTH TX...AND THIS CAP WAS LIKELY RESPONSIBLE
FOR THE DEARTH OF PRECIPITATION ALONG THE PORTION OF THE FRONT IN
TEXAS EARLY THIS MORNING.
TODAY AND TONIGHT...GUIDANCE CONSISTENTLY INDICATES THAT THE
CYCLONIC CIRCULATION/UPPER LOW OVER THE KS/OK BORDER EARLY THIS
MORNING WILL DEEPEN INTO A CLOSED LOW WHILE MOVING EAST OVER THE
NEXT 24 HRS. THIS WILL CAUSE THE CYCLONIC SHEAR AXIS TO SWING
SOUTHEAST IN ITS WAKE OVER THE CWA LATE THIS AFTERNOON THROUGH THE
OVERNIGHT HRS. THE EVOLUTION OF THIS UPPER LEVEL SYSTEM WILL HAVE
SOME INTERESTING IMPACTS ON SURFACE FEATURES ACROSS NORTH AND
CENTRAL TX TODAY.
THE SURFACE LOW THAT WAS LOCATED JUST EAST OF WICHITA FALLS AT THE
TIME OF THIS DISCUSSION IS EXPECTED TO MOVE EAST NORTHEAST WITH
THE MAIN UPPER LOW OVER THE NEXT 24 HRS. THIS WILL CAUSE THE COLD
FRONT TO CONTINUE SOUTH ACROSS THE CWA THROUGH THIS AFTERNOON. AS
THE SURFACE LOW IS MOVING EAST ACROSS AR TODAY ANOTHER SURFACE LOW
IS EXPECTED TO DEVELOP OVER NORTHERN MEXICO TO THE WEST OF DEL RIO
IN RESPONSE TO THE CYCLONIC SHEAR AXIS MOVING SOUTHEAST. WITH A
NEW SURFACE LOW DEVELOPING TO THE SOUTHWEST...AND THE OTHER
SURFACE LOW MOVING OFF TO THE EAST...THE COLD FRONT WILL LIKELY
STALL OUT NEAR OR JUST SOUTHEAST OF A LINE FROM ATHENS TO WACO BY
THE MID-AFTERNOON HOURS.
OVERNIGHT MODELS ARE STILL NOT IN COMPLETE AGREEMENT AS TO WHERE
THE FRONT WILL COME TO A REST...BUT SOMEWHERE BETWEEN WACO AND
COLLEGE STATION IS THE CONSENSUS LOCATION. WHEREVER THE FRONT
STALLS...WITH LOW PRESSURE OFF TO THE NORTHEAST AND
SOUTHWEST...THE GENERAL LOW LEVEL WIND FIELD LOOKS TO BE
DOMINATED BY VERY WEAK DEFORMATION ON EITHER SIDE OF THE STALLED
FRONT THIS AFTERNOON. WEAK NORTHEAST WINDS NORTH OF THE FRONT AND
WEAK SOUTHWEST WINDS TO THE SOUTH WILL ACTUALLY MINIMIZE PURE
CONVERGENCE ALONG THE FRONT...MAKING IT VERY DIFFICULT TO
DETERMINE IF THE FRONT WILL BE AN IMPORTANT SOURCE OF LIFT THIS
AFTERNOON.
TEMPERATURES WILL GENERALLY BE WARMER SOUTHEAST OF THE
FRONT...BUT THE GULF MOISTURE IN PLACE WILL ACTUALLY SUPPORT
CLOUDIER CONDITIONS TO THE SOUTHEAST OF THE FRONT THIS AFTERNOON.
DRIER AIR TO THE NORTH COMBINED WITH SUBSIDENCE IN THE WAKE OF THE
DEPARTING UPPER LOW WILL CAUSE SKIES TO CLEAR OUT NORTH OF THE
FRONT. AFTERNOON SUNSHINE WILL WEAKEN THE TEMPERATURE GRADIENT
ALONG THE FRONT...REDUCING FRONTOGENETIC FORCING DURING THE PEAK
HEATING HRS OF THE DAY. AS A RESULT THINK MESOSCALE FORCING FOR
ASCENT ALONG THE FRONT WILL BE FAIRLY WEAK THIS AFTERNOON...
REDUCING CONFIDENCE IN CONVECTION INITIATION ALONG THE STALLED OUT
FRONT DURING THE PEAK HEATING HRS OF THE DAY.
AS A RESULT...BUMPED POPS DOWN A LITTLE BIT THRU SUNSET FOR
LOCATIONS ALONG AND SOUTH OF A LINE FROM COMANCHE TO CANTON.
GUIDANCE CONTINUES TO INDICATE THAT THERE WILL BE OVER 2000 J/KG
OF CAPE AVAILABLE FOR FREE CONVECTION IF STORMS CAN DEVELOP ALONG
THE FRONT. THEREFORE DESPITE THE LOW POPS...WILL CONTINUE TO
MENTION A CHANCE OF STRONG TO SEVERE STORMS AS ANYTHING THAT DOES
MANAGE TO DEVELOP WILL LIKELY BE QUITE STRONG THIS AFTERNOON.
DAMAGING WINDS AND LARGE HAIL WOULD BE THE MOST LIKELY HAZARDS IF
ANYTHING WERE ABLE TO DEVELOP ALONG THE FRONT THRU SUNSET.
TONIGHT...THE DRIER AIR TO THE NORTH WILL ACTUALLY HELP INCREASE
THE THERMAL GRADIENT ALONG THE STALLED OUT FRONT AS THIS AIR WILL
COOL MORE QUICKLY THAN THE CLOUDY AND MORE MOIST AIRMASS TO THE
SOUTH OF THE FRONT. AS A RESULT...EVEN THOUGH THIS SEEMS
COUNTER-INTUITIVE...OUR BEST CHANCES FOR STORMS ALONG THE FRONT MAY
BE WELL AFTER SUNSET TONIGHT. MODELS DO NOT REALLY INDICATE A BIG
INCREASE IN CONVERGENCE ALONG THE FRONT...BUT THE INCREASE IN THE
THERMAL GRADIENT WILL LEAD TO STRONGER MESOSCALE FORCING FOR
ASCENT. THIS COMBINED WITH THE MEAGER LARGE SCALE SUPPORT OFFERED
BY THE CYCLONIC SHEAR AXIS MOVING OVER THE REGION HAS CONFIDENCE A
BIT HIGHER IN STORMS ALONG THE FRONT AFTER SUNSET. AS A RESULT
WENT AHEAD AND BUMPED UP POPS FROM 00-12Z ALONG THE FRONT FOR
TONIGHT. SEVERE WEATHER CHANCES WILL NOT BE AS GREAT AFTER
SUNSET...HOWEVER LARGE HAIL IS STILL A POSSIBILITY WITH THE
STRONGEST STORMS. ANY STORMS THAT DEVELOP WILL LIKELY MOVE
PARALLEL TO THE FRONT...SO THERE IS A RISK FOR LOCALLY HEAVY
RAINFALL DUE TO THE POTENTIAL FOR STORMS TO TRAIN ALONG THE FRONT
TONIGHT. THAT SAID...POPS ARE ONLY IN THE 30 TO 40 PERCENT CHANCE
RANGE...SO IT IS STILL POSSIBLE THAT FORCING REMAINS TOO WEAK FOR
ANYTHING ALONG THE FRONT OVERNIGHT.
SUNDAY THROUGH TUESDAY...GUIDANCE INDICATES THAT WEAK UPPER LEVEL
RIDGING WILL BUILD OVER THE NORTHERN PORTIONS OF THE SOUTH PLAINS
DURING THE PERIOD WHICH SHOULD HELP KEEP US DRY. THE ECMWF
STUBBORNLY INDICATES THAT THE TAILING END OF THE CYCLONIC SHEAR
AXIS MOVING SOUTH OVER TX TONIGHT WILL BECOME ISOLATED FROM THE
DEPARTING UPPER LOW/SHEAR AXIS AND FORM A WEAK CUT-OFF UPPER LOW
OVER THE TX GULF COAST DURING THIS PERIOD. BASED ON THE ECMWFS
EVOLUTION AND TRACK OF THIS FEATURE...IT IS SOMEWHAT
INCONSEQUENTIAL TO NORTH AND CENTRAL TX AS WE WOULD REMAIN NORTH
OR NORTHWEST OF THIS UPPER LOW THRU THE PERIOD. THE ECMWF HAS BEEN
CONSISTENT WITH THIS FEATURE...SO CONFIDENCE IS HIGHER THAT IT
WILL DEVELOP...HOWEVER THIS SHOULD JUST REINFORCE RIDGING OVER THE
CWA INCREASING CONFIDENCE IN A DRY FORECAST FROM SUNDAY AFTERNOON
THRU TUESDAY. EVEN IF THE UPPER LOW DEVELOPS...IT IS EXPECTED TO
REMAIN TOO WEAK TO HAVE A LARGE IMPACT ON THE SURFACE PRESSURE
PATTERN...THEREFORE WE SHOULD REMAIN IN SOUTHERLY FLOW DUE TO LEE
SIDE TROUGHING IN RESPONSE TO A POWERFUL UPPER LOW EXPECTED TO
SWING INTO THE PLAINS MID-WEEK. SOUTH WINDS AND SUBSIDENCE ALOFT
SHOULD HELP US BRING TEMPERATURES UP INTO THE 80S DURING THIS
PERIOD.
MID-WEEK...MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE ON THE
EXACT EVOLUTION OF THE POWERFUL SYSTEM PROGGED TO MOVE OVER THE
PLAINS WEDNESDAY OR WEDNESDAY NIGHT. ASIDE FROM THE FAIRLY LARGE
PLACEMENT DISCREPANCIES BETWEEN THE GFS AND CANADIAN/ECMWF ALL
GUIDANCE AGREES THAT THIS UPPER LEVEL SYSTEM WILL BE UNSEASONABLY
STRONG AND MAY LEAD TO AN EXTENDED PERIOD OF BELOW NORMAL
TEMPERATURES FOR NORTH TX FOR THE FIRST SEVERAL DAYS OF MAY. THIS
FORECAST IS MOST IN LINE WITH THE CONSENSUS OF THE ECMWF/CANADIAN
OPERATIONAL MODELS THAT WERE VALID AT 27/00Z. THESE MODELS BRING
THE INITIAL UPPER LEVEL LOW OVER THE SOUTH PLAINS DRIVING A STRONG
COLD FRONT SOUTH ACROSS NORTH TX LATE WEDNESDAY AFTERNOON THRU THE
OVERNIGHT HRS.
ASSUMING THE UPPER LOW DIGS AS FAR SOUTH AS THESE MODELS
INDICATE...ALMOST ALL OF THE CWA WILL SEE SOME RAIN/THUNDERSTORMS
ALONG THE COLD FRONT AS IT MOVES THROUGH. DID NOT GO CRAZY WITH
THE POPS YET BECAUSE THE GFS CONTINUES TO INDICATE THAT THE UPPER
LOW WILL REMAIN SIGNIFICANTLY FURTHER NORTH...REDUCING
PRECIPITATION CHANCES ALONG THE FRONT. WENT AHEAD WITH 40 POPS
ALONG AND BEHIND THE FRONT WITH THIS FORECAST...BUT POPS MAY NEED
TO BE MUCH HIGHER IF THE CMC/ECMWF TRACK VERIFIES. ITS TOO EARLY
TO DETERMINE SEVERE WEATHER CHANCES...HOWEVER A LARGE OUTBREAK
DOES NOT LOOK LIKELY BECAUSE THE FRONT IS EXPECTED TO MOVE SOUTH
VERY QUICKLY WEDNESDAY AFTERNOON UNDERCUTTING MOST ORGANIZED
CONVECTION THAT INITIATES JUST OUT AHEAD OF THE FRONT.
EXTENDED...THE ECMWF INDICATES THAT A BIG BLOCKING PATTERN SETS
UP AFTER THE UPPER LOW MOVES INTO THE PLAINS FOR THE END OF THE
WEEK. THIS KEEPS THE UPPER LOW IN PLACE OVER THE CENTRAL PLAINS
THRU AT LEAST MAY 5TH...WHICH WOULD TEND TO KEEP TEMPERATURES
BELOW NORMAL OVER MOST OF THE CENTRAL AND SOUTHERN PLAINS THRU THE
FIRST WEEK OF MAY. THE COLDEST TEMPERATURES WOULD BE RIGHT AFTER
THE COLD FRONT...WITH TEMPERATURES MODERATING THEREAFTER AS THE
UPPER LOW DRIFTS NORTH OF THE CWA. CONFIDENCE IN THIS SOLUTION IS
NOT GREAT...HOWEVER MOST GUIDANCE INDICATES SOME SORT OF BLOCKING
PATTERN FOR LATE IN THE WEEK INTO NEXT WEEKEND...SO THE MAIN
FORECAST CONCERN IS WHERE WILL THE UPPER LOW BE WHEN THE BLOCKING
PATTERN SETS UP. AT THIS TIME KEPT TEMPERATURES BELOW NORMAL
DURING THIS PERIOD AS THERE IS NO GUIDANCE THAT SHOWS WE GET STUCK
IN A BLOCKING PATTERN WITH UPPER LEVEL RIDGING OVER THE PLAINS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 56 81 59 86 / 10 5 5 0 0
WACO, TX 83 60 81 57 85 / 20 30 10 0 0
PARIS, TX 78 52 79 52 82 / 10 5 5 0 0
DENTON, TX 77 53 81 55 86 / 10 5 5 0 0
MCKINNEY, TX 77 53 80 56 85 / 10 5 5 0 0
DALLAS, TX 80 56 83 61 86 / 10 10 5 0 0
TERRELL, TX 80 54 81 55 84 / 20 10 5 0 0
CORSICANA, TX 83 59 81 58 83 / 20 20 5 0 0
TEMPLE, TX 84 62 80 58 84 / 30 40 20 0 0
MINERAL WELLS, TX 80 54 83 56 85 / 10 5 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
84/58
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1018 AM CDT SAT APR 27 2013
.UPDATE...
A COLD FRONT EXTENDED FROM JUST WEST OF PARIS TO SOUTHEAST OF
GREENVILLE...TERRELL...WEST...GATESVILLE AND LAMPASAS AT 16Z.
THIS FRONT WILL MOVE THROUGH WACO IN THE HALF HOUR...BUT STALL
OUT OVER THE SOUTHEASTERN PART OF THE FORECAST AREA THIS
AFTERNOON. HAVE ADJUSTED THE HOURLY WIND/TEMPERATURE/DEW POINT
GRIDS BASED ON THE LATEST RUC GUIDANCE WHICH SEEMS TO BE IN LINE
WITH ONGOING TRENDS.
THE 06Z TEXAS TECH WRF AND THE LATEST /12Z/ HIGH RESOLUTION RAPID
REFRESH...INDICATE THAT BUT MOST OF THE SHOWERS AND THUNDERSTORMS
WILL BE TO THE SOUTH OF THE FORECAST AREA THIS AFTERNOON WITH A
LITTLE MORE MOVING INTO THE SOUTHEASTERN ZONES AFTER 23Z. FOR
NOW...HAVE LEFT POPS AS IS...BUT WE MAY BE ABLE TO TRIM A LITTLE
OFF LATER THIS AFTERNOON DEPENDING ON EXACTLY WHERE THE FRONT
STALLS.
58
&&
.AVIATION...
COLD FRONT IS KNOCKING ON THE METROPLEX/S DOOR THIS MORNING. FRONT
IS THROUGH ALLIANCE...AND WILL BE THROUGH THE OTHER 4 SITES IN THE
METRO WITHIN THE NEXT HOUR. LOW CLOUDS HAVE BEEN SCATTERED AHEAD
OF THE FRONT...BUT REMAIN IN PLACE NEAR WACO WHERE THE BEST LOW-
LEVEL MOISTURE IS LOCATED. LOW CLOUDS ARE EXPECTED TO FILL IN
BEHIND THE COLD FRONT. WILL START THE METRO TAF SITES OFF WITH A
NORTHWEST WIND AND LOW MVFR CIGS...EXCEPT KDAL AND KGKY WHERE THE
FROPA IS EXPECTED CLOSER TO 1230Z. CURRENT EXTRAPOLATION HAS THE
FRONT REACHING WACO AROUND 17Z...BEFORE STALLING SOUTH OF THE
AIRPORT. WILL KEEP MVFR IN THE TAFS UNTIL 17Z FOR THE METRO AND
21Z FOR WACO. THIS TIMING IS CLOSE TO WHAT THE LATEST RAP IS
SHOWING. LOW CLOUDS DO NOT EXTEND TOO FAR WEST...AND CLEARING
SHOULD OCCUR EARLIER THAN PREVIOUSLY EXPECTED. CANT RULE OUT A
SHOWER OR THUNDERSTORM CLOSER TO THE FRONT NEAR WACO THIS
AFTERNOON...BUT PROBABILITIES ARE TOO LOW TO MENTION IN THE TAF AT
THIS TIME.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 27 2013/
EARLY MORNING WATER VAPOR IMAGERY DEPICTED A CYCLONIC CIRCULATION
CENTERED OVER SOUTH CENTRAL KS OR NORTH CENTRAL OK MOVING EAST.
THIS CIRCULATION WAS LOCATED ON THE EAST END OF A POSITIVELY
TILTED CYCLONIC SHEAR AXIS EXTENDING WSW OVER THE TX PANHANDLE AND
OVER WEST CENTRAL AZ. TO THE EAST OF THE KS/OK UPPER LOW WAS A
LINE OF LOOSELY ORGANIZED THUNDERSTORMS LOCATED FROM NORTHWESTERN
AR SOUTHWEST TO SOUTHEAST OK. 08Z /3AM/ SURFACE OBSERVATIONS
DEPICTED A COLD FRONT LOCATED NEAR A BOWIE TO PK LAKE TO COMANCHE
LINE MOVING SOUTHEAST. THE FWD 00Z RAOB INDICATED A SUBSTANTIAL
CAP IN PLACE OVER NORTH TX...AND THIS CAP WAS LIKELY RESPONSIBLE
FOR THE DEARTH OF PRECIPITATION ALONG THE PORTION OF THE FRONT IN
TEXAS EARLY THIS MORNING.
TODAY AND TONIGHT...GUIDANCE CONSISTENTLY INDICATES THAT THE
CYCLONIC CIRCULATION/UPPER LOW OVER THE KS/OK BORDER EARLY THIS
MORNING WILL DEEPEN INTO A CLOSED LOW WHILE MOVING EAST OVER THE
NEXT 24 HRS. THIS WILL CAUSE THE CYCLONIC SHEAR AXIS TO SWING
SOUTHEAST IN ITS WAKE OVER THE CWA LATE THIS AFTERNOON THROUGH THE
OVERNIGHT HRS. THE EVOLUTION OF THIS UPPER LEVEL SYSTEM WILL HAVE
SOME INTERESTING IMPACTS ON SURFACE FEATURES ACROSS NORTH AND
CENTRAL TX TODAY.
THE SURFACE LOW THAT WAS LOCATED JUST EAST OF WICHITA FALLS AT THE
TIME OF THIS DISCUSSION IS EXPECTED TO MOVE EAST NORTHEAST WITH
THE MAIN UPPER LOW OVER THE NEXT 24 HRS. THIS WILL CAUSE THE COLD
FRONT TO CONTINUE SOUTH ACROSS THE CWA THROUGH THIS AFTERNOON. AS
THE SURFACE LOW IS MOVING EAST ACROSS AR TODAY ANOTHER SURFACE LOW
IS EXPECTED TO DEVELOP OVER NORTHERN MEXICO TO THE WEST OF DEL RIO
IN RESPONSE TO THE CYCLONIC SHEAR AXIS MOVING SOUTHEAST. WITH A
NEW SURFACE LOW DEVELOPING TO THE SOUTHWEST...AND THE OTHER
SURFACE LOW MOVING OFF TO THE EAST...THE COLD FRONT WILL LIKELY
STALL OUT NEAR OR JUST SOUTHEAST OF A LINE FROM ATHENS TO WACO BY
THE MID-AFTERNOON HOURS.
OVERNIGHT MODELS ARE STILL NOT IN COMPLETE AGREEMENT AS TO WHERE
THE FRONT WILL COME TO A REST...BUT SOMEWHERE BETWEEN WACO AND
COLLEGE STATION IS THE CONSENSUS LOCATION. WHEREVER THE FRONT
STALLS...WITH LOW PRESSURE OFF TO THE NORTHEAST AND
SOUTHWEST...THE GENERAL LOW LEVEL WIND FIELD LOOKS TO BE
DOMINATED BY VERY WEAK DEFORMATION ON EITHER SIDE OF THE STALLED
FRONT THIS AFTERNOON. WEAK NORTHEAST WINDS NORTH OF THE FRONT AND
WEAK SOUTHWEST WINDS TO THE SOUTH WILL ACTUALLY MINIMIZE PURE
CONVERGENCE ALONG THE FRONT...MAKING IT VERY DIFFICULT TO
DETERMINE IF THE FRONT WILL BE AN IMPORTANT SOURCE OF LIFT THIS
AFTERNOON.
TEMPERATURES WILL GENERALLY BE WARMER SOUTHEAST OF THE
FRONT...BUT THE GULF MOISTURE IN PLACE WILL ACTUALLY SUPPORT
CLOUDIER CONDITIONS TO THE SOUTHEAST OF THE FRONT THIS AFTERNOON.
DRIER AIR TO THE NORTH COMBINED WITH SUBSIDENCE IN THE WAKE OF THE
DEPARTING UPPER LOW WILL CAUSE SKIES TO CLEAR OUT NORTH OF THE
FRONT. AFTERNOON SUNSHINE WILL WEAKEN THE TEMPERATURE GRADIENT
ALONG THE FRONT...REDUCING FRONTOGENETIC FORCING DURING THE PEAK
HEATING HRS OF THE DAY. AS A RESULT THINK MESOSCALE FORCING FOR
ASCENT ALONG THE FRONT WILL BE FAIRLY WEAK THIS AFTERNOON...
REDUCING CONFIDENCE IN CONVECTION INITIATION ALONG THE STALLED OUT
FRONT DURING THE PEAK HEATING HRS OF THE DAY.
AS A RESULT...BUMPED POPS DOWN A LITTLE BIT THRU SUNSET FOR
LOCATIONS ALONG AND SOUTH OF A LINE FROM COMANCHE TO CANTON.
GUIDANCE CONTINUES TO INDICATE THAT THERE WILL BE OVER 2000 J/KG
OF CAPE AVAILABLE FOR FREE CONVECTION IF STORMS CAN DEVELOP ALONG
THE FRONT. THEREFORE DESPITE THE LOW POPS...WILL CONTINUE TO
MENTION A CHANCE OF STRONG TO SEVERE STORMS AS ANYTHING THAT DOES
MANAGE TO DEVELOP WILL LIKELY BE QUITE STRONG THIS AFTERNOON.
DAMAGING WINDS AND LARGE HAIL WOULD BE THE MOST LIKELY HAZARDS IF
ANYTHING WERE ABLE TO DEVELOP ALONG THE FRONT THRU SUNSET.
TONIGHT...THE DRIER AIR TO THE NORTH WILL ACTUALLY HELP INCREASE
THE THERMAL GRADIENT ALONG THE STALLED OUT FRONT AS THIS AIR WILL
COOL MORE QUICKLY THAN THE CLOUDY AND MORE MOIST AIRMASS TO THE
SOUTH OF THE FRONT. AS A RESULT...EVEN THOUGH THIS SEEMS
COUNTER-INTUITIVE...OUR BEST CHANCES FOR STORMS ALONG THE FRONT MAY
BE WELL AFTER SUNSET TONIGHT. MODELS DO NOT REALLY INDICATE A BIG
INCREASE IN CONVERGENCE ALONG THE FRONT...BUT THE INCREASE IN THE
THERMAL GRADIENT WILL LEAD TO STRONGER MESOSCALE FORCING FOR
ASCENT. THIS COMBINED WITH THE MEAGER LARGE SCALE SUPPORT OFFERED
BY THE CYCLONIC SHEAR AXIS MOVING OVER THE REGION HAS CONFIDENCE A
BIT HIGHER IN STORMS ALONG THE FRONT AFTER SUNSET. AS A RESULT
WENT AHEAD AND BUMPED UP POPS FROM 00-12Z ALONG THE FRONT FOR
TONIGHT. SEVERE WEATHER CHANCES WILL NOT BE AS GREAT AFTER
SUNSET...HOWEVER LARGE HAIL IS STILL A POSSIBILITY WITH THE
STRONGEST STORMS. ANY STORMS THAT DEVELOP WILL LIKELY MOVE
PARALLEL TO THE FRONT...SO THERE IS A RISK FOR LOCALLY HEAVY
RAINFALL DUE TO THE POTENTIAL FOR STORMS TO TRAIN ALONG THE FRONT
TONIGHT. THAT SAID...POPS ARE ONLY IN THE 30 TO 40 PERCENT CHANCE
RANGE...SO IT IS STILL POSSIBLE THAT FORCING REMAINS TOO WEAK FOR
ANYTHING ALONG THE FRONT OVERNIGHT.
SUNDAY THROUGH TUESDAY...GUIDANCE INDICATES THAT WEAK UPPER LEVEL
RIDGING WILL BUILD OVER THE NORTHERN PORTIONS OF THE SOUTH PLAINS
DURING THE PERIOD WHICH SHOULD HELP KEEP US DRY. THE ECMWF
STUBBORNLY INDICATES THAT THE TAILING END OF THE CYCLONIC SHEAR
AXIS MOVING SOUTH OVER TX TONIGHT WILL BECOME ISOLATED FROM THE
DEPARTING UPPER LOW/SHEAR AXIS AND FORM A WEAK CUT-OFF UPPER LOW
OVER THE TX GULF COAST DURING THIS PERIOD. BASED ON THE ECMWFS
EVOLUTION AND TRACK OF THIS FEATURE...IT IS SOMEWHAT
INCONSEQUENTIAL TO NORTH AND CENTRAL TX AS WE WOULD REMAIN NORTH
OR NORTHWEST OF THIS UPPER LOW THRU THE PERIOD. THE ECMWF HAS BEEN
CONSISTENT WITH THIS FEATURE...SO CONFIDENCE IS HIGHER THAT IT
WILL DEVELOP...HOWEVER THIS SHOULD JUST REINFORCE RIDGING OVER THE
CWA INCREASING CONFIDENCE IN A DRY FORECAST FROM SUNDAY AFTERNOON
THRU TUESDAY. EVEN IF THE UPPER LOW DEVELOPS...IT IS EXPECTED TO
REMAIN TOO WEAK TO HAVE A LARGE IMPACT ON THE SURFACE PRESSURE
PATTERN...THEREFORE WE SHOULD REMAIN IN SOUTHERLY FLOW DUE TO LEE
SIDE TROUGHING IN RESPONSE TO A POWERFUL UPPER LOW EXPECTED TO
SWING INTO THE PLAINS MID-WEEK. SOUTH WINDS AND SUBSIDENCE ALOFT
SHOULD HELP US BRING TEMPERATURES UP INTO THE 80S DURING THIS
PERIOD.
MID-WEEK...MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE ON THE
EXACT EVOLUTION OF THE POWERFUL SYSTEM PROGGED TO MOVE OVER THE
PLAINS WEDNESDAY OR WEDNESDAY NIGHT. ASIDE FROM THE FAIRLY LARGE
PLACEMENT DISCREPANCIES BETWEEN THE GFS AND CANADIAN/ECMWF ALL
GUIDANCE AGREES THAT THIS UPPER LEVEL SYSTEM WILL BE UNSEASONABLY
STRONG AND MAY LEAD TO AN EXTENDED PERIOD OF BELOW NORMAL
TEMPERATURES FOR NORTH TX FOR THE FIRST SEVERAL DAYS OF MAY. THIS
FORECAST IS MOST IN LINE WITH THE CONSENSUS OF THE ECMWF/CANADIAN
OPERATIONAL MODELS THAT WERE VALID AT 27/00Z. THESE MODELS BRING
THE INITIAL UPPER LEVEL LOW OVER THE SOUTH PLAINS DRIVING A STRONG
COLD FRONT SOUTH ACROSS NORTH TX LATE WEDNESDAY AFTERNOON THRU THE
OVERNIGHT HRS.
ASSUMING THE UPPER LOW DIGS AS FAR SOUTH AS THESE MODELS
INDICATE...ALMOST ALL OF THE CWA WILL SEE SOME RAIN/THUNDERSTORMS
ALONG THE COLD FRONT AS IT MOVES THROUGH. DID NOT GO CRAZY WITH
THE POPS YET BECAUSE THE GFS CONTINUES TO INDICATE THAT THE UPPER
LOW WILL REMAIN SIGNIFICANTLY FURTHER NORTH...REDUCING
PRECIPITATION CHANCES ALONG THE FRONT. WENT AHEAD WITH 40 POPS
ALONG AND BEHIND THE FRONT WITH THIS FORECAST...BUT POPS MAY NEED
TO BE MUCH HIGHER IF THE CMC/ECMWF TRACK VERIFIES. ITS TOO EARLY
TO DETERMINE SEVERE WEATHER CHANCES...HOWEVER A LARGE OUTBREAK
DOES NOT LOOK LIKELY BECAUSE THE FRONT IS EXPECTED TO MOVE SOUTH
VERY QUICKLY WEDNESDAY AFTERNOON UNDERCUTTING MOST ORGANIZED
CONVECTION THAT INITIATES JUST OUT AHEAD OF THE FRONT.
EXTENDED...THE ECMWF INDICATES THAT A BIG BLOCKING PATTERN SETS
UP AFTER THE UPPER LOW MOVES INTO THE PLAINS FOR THE END OF THE
WEEK. THIS KEEPS THE UPPER LOW IN PLACE OVER THE CENTRAL PLAINS
THRU AT LEAST MAY 5TH...WHICH WOULD TEND TO KEEP TEMPERATURES
BELOW NORMAL OVER MOST OF THE CENTRAL AND SOUTHERN PLAINS THRU THE
FIRST WEEK OF MAY. THE COLDEST TEMPERATURES WOULD BE RIGHT AFTER
THE COLD FRONT...WITH TEMPERATURES MODERATING THEREAFTER AS THE
UPPER LOW DRIFTS NORTH OF THE CWA. CONFIDENCE IN THIS SOLUTION IS
NOT GREAT...HOWEVER MOST GUIDANCE INDICATES SOME SORT OF BLOCKING
PATTERN FOR LATE IN THE WEEK INTO NEXT WEEKEND...SO THE MAIN
FORECAST CONCERN IS WHERE WILL THE UPPER LOW BE WHEN THE BLOCKING
PATTERN SETS UP. AT THIS TIME KEPT TEMPERATURES BELOW NORMAL
DURING THIS PERIOD AS THERE IS NO GUIDANCE THAT SHOWS WE GET STUCK
IN A BLOCKING PATTERN WITH UPPER LEVEL RIDGING OVER THE PLAINS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 56 81 59 86 / 10 5 5 0 0
WACO, TX 83 60 81 57 85 / 20 30 10 0 0
PARIS, TX 78 52 79 52 82 / 10 5 5 0 0
DENTON, TX 77 53 81 55 86 / 10 5 5 0 0
MCKINNEY, TX 77 53 80 56 85 / 10 5 5 0 0
DALLAS, TX 80 56 83 61 86 / 10 10 5 0 0
TERRELL, TX 80 54 81 55 84 / 20 10 5 0 0
CORSICANA, TX 83 59 81 58 83 / 20 20 5 0 0
TEMPLE, TX 84 62 80 58 84 / 30 40 20 0 0
MINERAL WELLS, TX 80 54 83 56 85 / 10 5 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
84/58
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
631 AM CDT SAT APR 27 2013
.DISCUSSION...
SEE AVIATION FOR THE 12Z TAF DISCUSSION.
&&
.AVIATION...
THE PRIMARY CHALLENGE FOR THIS TAF PACKAGE IS THE TIMING OF THUNDERSTORMS
FOR THIS EVENING INTO EARLY TONIGHT. A WEAK FRONTAL BOUNDARY WILL FILTER
SOUTHWARD ACROSS THE HILL COUNTRY THIS EVENING BECOMING STATIONARY IN
THE VICINITY OF HIGHWAY 90 WHILE AN UPPER LEVEL IMPULSE MOVES EASTWARD
OUT OF MEXICO. THE FRONTAL BOUNDARY AND THE EASTERN SLOPES OF THE SIERRA
MADRE WILL BE THE FOCUS AREAS OF CONVECTIVE DEVELOPMENT. THE UPPER LEVEL
DISTURBANCE WILL HELP IN THE PROPAGATION OF CONVECTION TO THE EAST AND
SOUTHEAST OVERNIGHT. A BLEND OF THE 00Z ARW...07Z RUC13 AND 00Z TTU
3KM WRF WILL BE USED FOR TIMING OF THUNDERSTORMS IMPACTING THE TAF
SITES. OTHERWISE MVFR CIGS WILL PREVAIL THIS MORNING IMPROVING TO VFR
THIS AFTERNOON. CIGS WILL ONCE AGAIN LOWER TO MVFR AFTER 06Z...IFR BY
11Z. SFC WINDS TODAY S TO SE AT 5 TO 10 KTS...BACKING TO THE EAST AT
5 TO 8 KTS OVERNIGHT BECOMING L/V BY SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT SAT APR 27 2013/
SHORT TERM (TODAY THROUGH SUNDAY)...
INCREASING CHANCES FOR RAIN THIS WEEKEND AS A COLD FRONT SLIDES INTO
THE REGION. FOR TODAY...A CONTINUED SOUTHEAST INFLUX OF LOW LEVEL
MOISTURE WILL KEEP THE AREA POTENTIALLY UNSTABLE AS BOUNDARIES
APPROACH THE AREA. A MIXED LAYER CAP ALOFT WILL KEEP MUCH
CONVECTION FROM FIRING UNTIL AFTER DARK WHEN LOW LEVEL CONVERGENT
FORCES TAKE OVER (ALONG WITH SUPPORT ALOFT FROM A MID LEVEL JET).
HIGHS TODAY WILL BE IN THE 80S. WILL PLACE AT LEAST A SLIGHT
CHANCE OF THUNDERSTORMS OVER OUR NORTHERN CWA ALONG THE FRONT FOR
THIS AFTERNOON. THE COLD FRONT...LOCATED EARLY THIS MORNING OVER
THE TEXAS SOUTH PLAINS WILL SLIP SOUTH INTO OUR NORTHERN CWA BY
AFTERNOON. THE GFS MODEL SOLUTION STALLS THE FRONT OVER OVER
NORTHERN CWA DURING THE EVENING...THEN EDGES IT SOUTHWARD INTO THE
CENTRAL CWA OVERNIGHT. THIS IS SIGNIFICANT IN AS FAR AS RAINFALL
AND POTENTIALLY SEVERE WEATHER ARE CONCERNED AS BURRO MOUNTAIN
(MEXICAN PLATEAU) STORMS WHICH DEVELOP DURING THE LATE AFTERNOON/
EVENING HOURS PUSH EASTWARD AND INTERSECT THE FRONT DURING THE
OVERNIGHT HOURS OVER WESTERN SECTIONS. MOIST LOW LEVEL SOUTHEAST
FLOW (DEWPOINTS IN UPPER 60S) WILL MAINTAIN THESE STORMS AS THEY
TRAVERSE EAST...INTERSECTING THE FRONT AND ENHANCING RAIN AMOUNTS
AND SEVERITY OF STORMS. WILL INCLUDE A CHANCE OF SOME OF THE
STORMS BECOMING SEVERE TONIGHT OVER THE WESTERN HALF OF THE CWA
..WITH THE GREATEST THREAT BEING FROM LARGE HAIL. SOME DAMAGING
WIND GUSTS ARE ALSO POSSIBLE. ISOLATED RAIN AMOUNTS OF 1 TO 3
INCHES ARE EXPECTED ALONG THE TRACK OF THE BURRO STORMS AS THEY
INTERSECT THE FRONT OVER WESTERN SECTIONS TONIGHT. SOME
STABILIZATION IS EXPECTED SUNDAY AS THE FRONT AND RAIN-COOLED AIR
SETTLE OVER THE AREA. HOWEVER THERE REMAINS ENOUGH DYNAMICS AND
INSTABILITY ALOFT FOR SOME RE-DEVELOPMENT OF STORMS IN DAYTIME
HEATING. HIGHS SUNDAY IN THE UPPER 70S HILLS...NEAR 80 TO LOW 80S
ELSEWHERE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
AS FRONTOLYSIS (DISSIPATION OR WEAKENING OF A FRONT) OCCURS SUNDAY
NIGHT...SOUTHEAST FLOW AND LIFT OVER THE WEAKENING BOUNDARY MAY BE
ENOUGH FOR ADDITIONAL CONVECTION. IN FACT...ANOTHER THREAT FOR
BURRO DEVELOPMENT MAY OCCUR OVERNIGHT SUNDAY/EARLY MONDAY MORNING
AS MOIST SOUTHEAST FLOW UPLIFTS ACROSS THE MEXICAN PLATEAU AMID A
WEAK UPPER LEVEL SUBTROPICAL JET. THIS INSTABILITY AND UNSETTLED
WEATHER PATTERN WILL LINGER THROUGH TUESDAY AS A MOIST SOUTHEAST
FLOW AT THE SURFACE AND COOLING ALOFT COUPLED WITH DISTURBANCES
TRIGGER FURTHER ACTIVITY ESPECIALLY OVER SOUTHWEST PORTIONS OF THE
CWA. THE UPPER TROUGH WILL EXIT THE REGION WEDNESDAY WITH A STABLE
NORTHERLY FLOW ALOFT IN PLACE. A STRONG COLD FRONT WILL THEN PUSH
RAPIDLY THROUGH THE REGION WEDNESDAY NIGHT WITH LOW CHANCES OF
SHOWERS AND THUNDERSTORMS LINING THE FRONT. DECREASING CLOUDINESS
AND MUCH COOLER THURSDAY WITH HIGHS GENERALLY IN THE 70S. SURFACE
RIDGING WILL SETTLE OVER THE AREA THURSDAY NIGHT AND EARLY FRIDAY
WITH LOWS FRIDAY MORNING MOSTLY IN THE 40S. MOSTLY SUNNY FRIDAY
WITH HIGHS IN THE 70S.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 84 62 83 60 84 / 10 50 30 10 10
AUSTIN BERGSTROM INTL AIRPORT 84 61 82 57 83 / 10 50 30 20 10
NEW BRAUNFELS MUNI AIRPORT 85 61 83 58 83 / 10 60 40 20 20
BURNET MUNI AIRPORT 83 60 81 57 83 / 20 50 20 10 10
DEL RIO INTL AIRPORT 85 66 81 64 84 / 10 60 40 30 20
GEORGETOWN MUNI AIRPORT 82 61 81 58 82 / 20 50 20 10 10
HONDO MUNI AIRPORT 84 63 81 60 83 / 10 70 40 30 20
SAN MARCOS MUNI AIRPORT 83 62 82 58 82 / 10 50 30 20 20
LA GRANGE - FAYETTE REGIONAL 85 66 83 62 84 / 20 40 30 10 20
SAN ANTONIO INTL AIRPORT 83 63 81 60 82 / 10 60 40 30 20
STINSON MUNI AIRPORT 84 63 81 61 82 / 10 60 40 30 20
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...02
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
630 AM CDT SAT APR 27 2013
.AVIATION...
COLD FRONT IS KNOCKING ON THE METROPLEXS DOOR THIS MORNING. FRONT
IS THROUGH ALLIANCE...AND WILL BE THROUGH THE OTHER 4 SITES IN THE
METRO WITHIN THE NEXT HOUR. LOW CLOUDS HAVE BEEN SCATTERED AHEAD
OF THE FRONT...BUT REMAIN IN PLACE NEAR WACO WHERE THE BEST LOW-
LEVEL MOISTURE IS LOCATED. LOW CLOUDS ARE EXPECTED TO FILL IN
BEHIND THE COLD FRONT. WILL START THE METRO TAF SITES OFF WITH A
NORTHWEST WIND AND LOW MVFR CIGS...EXCEPT KDAL AND KGKY WHERE THE
FROPA IS EXPECTED CLOSER TO 1230Z. CURRENT EXTRAPOLATION HAS THE
FRONT REACHING WACO AROUND 17Z...BEFORE STALLING SOUTH OF THE
AIRPORT. WILL KEEP MVFR IN THE TAFS UNTIL 17Z FOR THE METRO AND
21Z FOR WACO. THIS TIMING IS CLOSE TO WHAT THE LATEST RAP IS
SHOWING. LOW CLOUDS DO NOT EXTEND TOO FAR WEST...AND CLEARING
SHOULD OCCUR EARLIER THAN PREVIOUSLY EXPECTED. CANT RULE OUT A
SHOWER OR THUNDERSTORM CLOSER TO THE FRONT NEAR WACO THIS
AFTERNOON...BUT PROBABILITIES ARE TOO LOW TO MENTION IN THE TAF AT
THIS TIME.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 415 AM CDT SAT APR 27 2013/
EARLY MORNING WATER VAPOR IMAGERY DEPICTED A CYCLONIC CIRCULATION
CENTERED OVER SOUTH CENTRAL KS OR NORTH CENTRAL OK MOVING EAST.
THIS CIRCULATION WAS LOCATED ON THE EAST END OF A POSITIVELY
TILTED CYCLONIC SHEAR AXIS EXTENDING WSW OVER THE TX PANHANDLE AND
OVER WEST CENTRAL AZ. TO THE EAST OF THE KS/OK UPPER LOW WAS A
LINE OF LOOSELY ORGANIZED THUNDERSTORMS LOCATED FROM NORTHWESTERN
AR SOUTHWEST TO SOUTHEAST OK. 08Z /3AM/ SURFACE OBSERVATIONS
DEPICTED A COLD FRONT LOCATED NEAR A BOWIE TO PK LAKE TO COMANCHE
LINE MOVING SOUTHEAST. THE FWD 00Z RAOB INDICATED A SUBSTANTIAL
CAP IN PLACE OVER NORTH TX...AND THIS CAP WAS LIKELY RESPONSIBLE
FOR THE DEARTH OF PRECIPITATION ALONG THE PORTION OF THE FRONT IN
TEXAS EARLY THIS MORNING.
TODAY AND TONIGHT...GUIDANCE CONSISTENTLY INDICATES THAT THE
CYCLONIC CIRCULATION/UPPER LOW OVER THE KS/OK BORDER EARLY THIS
MORNING WILL DEEPEN INTO A CLOSED LOW WHILE MOVING EAST OVER THE
NEXT 24 HRS. THIS WILL CAUSE THE CYCLONIC SHEAR AXIS TO SWING
SOUTHEAST IN ITS WAKE OVER THE CWA LATE THIS AFTERNOON THROUGH THE
OVERNIGHT HRS. THE EVOLUTION OF THIS UPPER LEVEL SYSTEM WILL HAVE
SOME INTERESTING IMPACTS ON SURFACE FEATURES ACROSS NORTH AND
CENTRAL TX TODAY.
THE SURFACE LOW THAT WAS LOCATED JUST EAST OF WICHITA FALLS AT THE
TIME OF THIS DISCUSSION IS EXPECTED TO MOVE EAST NORTHEAST WITH
THE MAIN UPPER LOW OVER THE NEXT 24 HRS. THIS WILL CAUSE THE COLD
FRONT TO CONTINUE SOUTH ACROSS THE CWA THROUGH THIS AFTERNOON. AS
THE SURFACE LOW IS MOVING EAST ACROSS AR TODAY ANOTHER SURFACE LOW
IS EXPECTED TO DEVELOP OVER NORTHERN MEXICO TO THE WEST OF DEL RIO
IN RESPONSE TO THE CYCLONIC SHEAR AXIS MOVING SOUTHEAST. WITH A
NEW SURFACE LOW DEVELOPING TO THE SOUTHWEST...AND THE OTHER
SURFACE LOW MOVING OFF TO THE EAST...THE COLD FRONT WILL LIKELY
STALL OUT NEAR OR JUST SOUTHEAST OF A LINE FROM ATHENS TO WACO BY
THE MID-AFTERNOON HOURS.
OVERNIGHT MODELS ARE STILL NOT IN COMPLETE AGREEMENT AS TO WHERE
THE FRONT WILL COME TO A REST...BUT SOMEWHERE BETWEEN WACO AND
COLLEGE STATION IS THE CONSENSUS LOCATION. WHEREVER THE FRONT
STALLS...WITH LOW PRESSURE OFF TO THE NORTHEAST AND
SOUTHWEST...THE GENERAL LOW LEVEL WIND FIELD LOOKS TO BE
DOMINATED BY VERY WEAK DEFORMATION ON EITHER SIDE OF THE STALLED
FRONT THIS AFTERNOON. WEAK NORTHEAST WINDS NORTH OF THE FRONT AND
WEAK SOUTHWEST WINDS TO THE SOUTH WILL ACTUALLY MINIMIZE PURE
CONVERGENCE ALONG THE FRONT...MAKING IT VERY DIFFICULT TO
DETERMINE IF THE FRONT WILL BE AN IMPORTANT SOURCE OF LIFT THIS
AFTERNOON.
TEMPERATURES WILL GENERALLY BE WARMER SOUTHEAST OF THE
FRONT...BUT THE GULF MOISTURE IN PLACE WILL ACTUALLY SUPPORT
CLOUDIER CONDITIONS TO THE SOUTHEAST OF THE FRONT THIS AFTERNOON.
DRIER AIR TO THE NORTH COMBINED WITH SUBSIDENCE IN THE WAKE OF THE
DEPARTING UPPER LOW WILL CAUSE SKIES TO CLEAR OUT NORTH OF THE
FRONT. AFTERNOON SUNSHINE WILL WEAKEN THE TEMPERATURE GRADIENT
ALONG THE FRONT...REDUCING FRONTOGENETIC FORCING DURING THE PEAK
HEATING HRS OF THE DAY. AS A RESULT THINK MESOSCALE FORCING FOR
ASCENT ALONG THE FRONT WILL BE FAIRLY WEAK THIS AFTERNOON...
REDUCING CONFIDENCE IN CONVECTION INITIATION ALONG THE STALLED OUT
FRONT DURING THE PEAK HEATING HRS OF THE DAY.
AS A RESULT...BUMPED POPS DOWN A LITTLE BIT THRU SUNSET FOR
LOCATIONS ALONG AND SOUTH OF A LINE FROM COMANCHE TO CANTON.
GUIDANCE CONTINUES TO INDICATE THAT THERE WILL BE OVER 2000 J/KG
OF CAPE AVAILABLE FOR FREE CONVECTION IF STORMS CAN DEVELOP ALONG
THE FRONT. THEREFORE DESPITE THE LOW POPS...WILL CONTINUE TO
MENTION A CHANCE OF STRONG TO SEVERE STORMS AS ANYTHING THAT DOES
MANAGE TO DEVELOP WILL LIKELY BE QUITE STRONG THIS AFTERNOON.
DAMAGING WINDS AND LARGE HAIL WOULD BE THE MOST LIKELY HAZARDS IF
ANYTHING WERE ABLE TO DEVELOP ALONG THE FRONT THRU SUNSET.
TONIGHT...THE DRIER AIR TO THE NORTH WILL ACTUALLY HELP INCREASE
THE THERMAL GRADIENT ALONG THE STALLED OUT FRONT AS THIS AIR WILL
COOL MORE QUICKLY THAN THE CLOUDY AND MORE MOIST AIRMASS TO THE
SOUTH OF THE FRONT. AS A RESULT...EVEN THOUGH THIS SEEMS
COUNTER-INTUITIVE...OUR BEST CHANCES FOR STORMS ALONG THE FRONT MAY
BE WELL AFTER SUNSET TONIGHT. MODELS DO NOT REALLY INDICATE A BIG
INCREASE IN CONVERGENCE ALONG THE FRONT...BUT THE INCREASE IN THE
THERMAL GRADIENT WILL LEAD TO STRONGER MESOSCALE FORCING FOR
ASCENT. THIS COMBINED WITH THE MEAGER LARGE SCALE SUPPORT OFFERED
BY THE CYCLONIC SHEAR AXIS MOVING OVER THE REGION HAS CONFIDENCE A
BIT HIGHER IN STORMS ALONG THE FRONT AFTER SUNSET. AS A RESULT
WENT AHEAD AND BUMPED UP POPS FROM 00-12Z ALONG THE FRONT FOR
TONIGHT. SEVERE WEATHER CHANCES WILL NOT BE AS GREAT AFTER
SUNSET...HOWEVER LARGE HAIL IS STILL A POSSIBILITY WITH THE
STRONGEST STORMS. ANY STORMS THAT DEVELOP WILL LIKELY MOVE
PARALLEL TO THE FRONT...SO THERE IS A RISK FOR LOCALLY HEAVY
RAINFALL DUE TO THE POTENTIAL FOR STORMS TO TRAIN ALONG THE FRONT
TONIGHT. THAT SAID...POPS ARE ONLY IN THE 30 TO 40 PERCENT CHANCE
RANGE...SO IT IS STILL POSSIBLE THAT FORCING REMAINS TOO WEAK FOR
ANYTHING ALONG THE FRONT OVERNIGHT.
SUNDAY THROUGH TUESDAY...GUIDANCE INDICATES THAT WEAK UPPER LEVEL
RIDGING WILL BUILD OVER THE NORTHERN PORTIONS OF THE SOUTH PLAINS
DURING THE PERIOD WHICH SHOULD HELP KEEP US DRY. THE ECMWF
STUBBORNLY INDICATES THAT THE TAILING END OF THE CYCLONIC SHEAR
AXIS MOVING SOUTH OVER TX TONIGHT WILL BECOME ISOLATED FROM THE
DEPARTING UPPER LOW/SHEAR AXIS AND FORM A WEAK CUT-OFF UPPER LOW
OVER THE TX GULF COAST DURING THIS PERIOD. BASED ON THE ECMWFS
EVOLUTION AND TRACK OF THIS FEATURE...IT IS SOMEWHAT
INCONSEQUENTIAL TO NORTH AND CENTRAL TX AS WE WOULD REMAIN NORTH
OR NORTHWEST OF THIS UPPER LOW THRU THE PERIOD. THE ECMWF HAS BEEN
CONSISTENT WITH THIS FEATURE...SO CONFIDENCE IS HIGHER THAT IT
WILL DEVELOP...HOWEVER THIS SHOULD JUST REINFORCE RIDGING OVER THE
CWA INCREASING CONFIDENCE IN A DRY FORECAST FROM SUNDAY AFTERNOON
THRU TUESDAY. EVEN IF THE UPPER LOW DEVELOPS...IT IS EXPECTED TO
REMAIN TOO WEAK TO HAVE A LARGE IMPACT ON THE SURFACE PRESSURE
PATTERN...THEREFORE WE SHOULD REMAIN IN SOUTHERLY FLOW DUE TO LEE
SIDE TROUGHING IN RESPONSE TO A POWERFUL UPPER LOW EXPECTED TO
SWING INTO THE PLAINS MID-WEEK. SOUTH WINDS AND SUBSIDENCE ALOFT
SHOULD HELP US BRING TEMPERATURES UP INTO THE 80S DURING THIS
PERIOD.
MID-WEEK...MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE ON THE
EXACT EVOLUTION OF THE POWERFUL SYSTEM PROGGED TO MOVE OVER THE
PLAINS WEDNESDAY OR WEDNESDAY NIGHT. ASIDE FROM THE FAIRLY LARGE
PLACEMENT DISCREPANCIES BETWEEN THE GFS AND CANADIAN/ECMWF ALL
GUIDANCE AGREES THAT THIS UPPER LEVEL SYSTEM WILL BE UNSEASONABLY
STRONG AND MAY LEAD TO AN EXTENDED PERIOD OF BELOW NORMAL
TEMPERATURES FOR NORTH TX FOR THE FIRST SEVERAL DAYS OF MAY. THIS
FORECAST IS MOST IN LINE WITH THE CONSENSUS OF THE ECMWF/CANADIAN
OPERATIONAL MODELS THAT WERE VALID AT 27/00Z. THESE MODELS BRING
THE INITIAL UPPER LEVEL LOW OVER THE SOUTH PLAINS DRIVING A STRONG
COLD FRONT SOUTH ACROSS NORTH TX LATE WEDNESDAY AFTERNOON THRU THE
OVERNIGHT HRS.
ASSUMING THE UPPER LOW DIGS AS FAR SOUTH AS THESE MODELS
INDICATE...ALMOST ALL OF THE CWA WILL SEE SOME RAIN/THUNDERSTORMS
ALONG THE COLD FRONT AS IT MOVES THROUGH. DID NOT GO CRAZY WITH
THE POPS YET BECAUSE THE GFS CONTINUES TO INDICATE THAT THE UPPER
LOW WILL REMAIN SIGNIFICANTLY FURTHER NORTH...REDUCING
PRECIPITATION CHANCES ALONG THE FRONT. WENT AHEAD WITH 40 POPS
ALONG AND BEHIND THE FRONT WITH THIS FORECAST...BUT POPS MAY NEED
TO BE MUCH HIGHER IF THE CMC/ECMWF TRACK VERIFIES. ITS TOO EARLY
TO DETERMINE SEVERE WEATHER CHANCES...HOWEVER A LARGE OUTBREAK
DOES NOT LOOK LIKELY BECAUSE THE FRONT IS EXPECTED TO MOVE SOUTH
VERY QUICKLY WEDNESDAY AFTERNOON UNDERCUTTING MOST ORGANIZED
CONVECTION THAT INITIATES JUST OUT AHEAD OF THE FRONT.
EXTENDED...THE ECMWF INDICATES THAT A BIG BLOCKING PATTERN SETS
UP AFTER THE UPPER LOW MOVES INTO THE PLAINS FOR THE END OF THE
WEEK. THIS KEEPS THE UPPER LOW IN PLACE OVER THE CENTRAL PLAINS
THRU AT LEAST MAY 5TH...WHICH WOULD TEND TO KEEP TEMPERATURES
BELOW NORMAL OVER MOST OF THE CENTRAL AND SOUTHERN PLAINS THRU THE
FIRST WEEK OF MAY. THE COLDEST TEMPERATURES WOULD BE RIGHT AFTER
THE COLD FRONT...WITH TEMPERATURES MODERATING THEREAFTER AS THE
UPPER LOW DRIFTS NORTH OF THE CWA. CONFIDENCE IN THIS SOLUTION IS
NOT GREAT...HOWEVER MOST GUIDANCE INDICATES SOME SORT OF BLOCKING
PATTERN FOR LATE IN THE WEEK INTO NEXT WEEKEND...SO THE MAIN
FORECAST CONCERN IS WHERE WILL THE UPPER LOW BE WHEN THE BLOCKING
PATTERN SETS UP. AT THIS TIME KEPT TEMPERATURES BELOW NORMAL
DURING THIS PERIOD AS THERE IS NO GUIDANCE THAT SHOWS WE GET STUCK
IN A BLOCKING PATTERN WITH UPPER LEVEL RIDGING OVER THE PLAINS.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 56 81 59 86 / 10 5 5 0 0
WACO, TX 83 60 81 57 85 / 20 30 10 0 0
PARIS, TX 78 52 79 52 82 / 30 5 5 0 0
DENTON, TX 77 53 81 55 86 / 10 5 5 0 0
MCKINNEY, TX 77 53 80 56 85 / 10 5 5 0 0
DALLAS, TX 80 56 83 61 86 / 10 10 5 0 0
TERRELL, TX 80 54 81 55 84 / 10 10 5 0 0
CORSICANA, TX 83 59 81 58 83 / 20 20 5 0 0
TEMPLE, TX 84 62 80 58 84 / 30 40 20 0 0
MINERAL WELLS, TX 80 54 83 56 85 / 10 5 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
155 AM EDT SAT APR 27 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE REGION TONIGHT WILL DRIFT OFF THE MID-
ATLANTIC COAST AS AN UPPER DISTURBANCE MOVES EAST FROM THE MID-
MISSISSIPPI VALLEY INTO THE SOUTHERN APPALACHIANS. THIS SYSTEM
WILL SLOW AND LINGER ACROSS THE REGION THROUGH THE MID-PART OF
NEXT WEEK...KEEPING CLOUDS...LIGHT RAIN...AND UNSEASONABLY COOL
TEMPERATURES IN PLACE. A NEW WEATHER SYSTEM WILL APPROACH FROM THE
WEST BY THE END OF NEXT WEEK WITH MORE SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 840 PM EDT FRIDAY...
SOUNDINGS SHOW VERY DRY AIR CONTINUING ESPCLY IN THE LOWER LEVELS
THIS EVENING WITH MOST ADVECTION OF MOISTURE COMING FROM THE WEST
ATTM. THIS DRY AIR HAS BASICALLY DRIED UP THE INITIAL BATCH OF
PRECIP HEADING IN FROM THE WEST WITH THE FIRST FAINT WAVE...WHILE
HAVE ANOTHER WEAK ARC OF ENERGY SET TO ARRIVE FROM TN/KY OVER THE
FAR WEST LATE. LATEST RAP PICKS UP ON THIS AFTER MIDNIGHT AND HAS
SOME SPOTTY -RA OVER THE NW NC RIDGES...AND AREAS WEST OF I-77 IN
VA LATE. MOST OTHER SHORT TERM GUIDANCE QUITE DRY SO ONLY
INCLUDING A SLIGHT POP FOR VERY -RA EXTREME SW BY DAWN. OTRW WILL
SEE VARYING AMOUNTS OF HIGH/MID CLOUDS...WITH A THICKER MID DECK
CANOPY DEVELOPING OVERNIGHT WEST...AND SOME THIN SPOTS OVER THE
NORTH/EAST. BUMPED UP LOW TEMPS A BIT SW DUE TO THICKER CLOUDS
WITH MOST SPOTS IN THE 40S BY MORNING...EXCEPT SOME 30S DEEPER
VALLEYS ACROSS THE NORTH.
HIGH PRESSURE WILL MOVE EAST OFF THE NEW ENGLAND COAST ON SATURDAY.
AN APPROACHING SHORTWAVE COMBINED WITH EASTERLY FLOW WILL INCREASE
MOISTURE ACROSS OUR REGION SATURDAY. PLACED THE HIGHEST POPS ON
SATURDAY ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS...WITH LIGHTER
CHANCES IN THE EAST. HIGH SATURDAY VARY FROM THE LOW 50S ACROSS THE
SOUTHWEST MOUNTAINS TO AROUND 70 IN THE PIEDMONT. A FASTER SPREAD OF
MOISTURE COULD TRIM HIGHS SATURDAY MORE WITH ADDITIONAL CLOUD COVER
AND RAIN.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 345 PM EDT FRIDAY...
ECMWF/GFS IN GENERAL AGREEMENT ON THE EVOLUTION OF THE PATTERN
SUN THROUGH MON...BUT CONTINUE TO DIFFER ON TIMING. HOWEVER...MOST
OF THE TIMING ISSUES APPEAR TO BE RESOLVED BY THE BEGINNING OF THE
SHORT TERM PERIOD. THIS PERIOD CAN BEST BE CHARACTERIZED AS A
RATHER CONTINUOUS PERIOD OF LIGHT RAIN AS A SOUTHERN STREAM
DISTURBANCE SPREADS THROUGH THE REGION IN A FAVORABLE WEDGE AREA.
THE WEDGE WILL BE ENHANCED/REINFORCED AS THE PCPN FALLS INTO AN
INITIALLY DRY/COOL SFC AIR MASS. QPF THROUGH THE PERIOD SHOULD
RANGE FROM 0.25 INCH IN THE NE PART OF THE CWA TO PERHAPS NEAR AN
INCH IN THE NW NC MOUNTAINS AND FAR SW VA. BY SUN AFTERNOON...THE
WEDGE MAY ERODE ENOUGH ALONG THE WESTERN EDGE...FROM MERCER COUNTY
WV DOWN TOWARD NE TN TO SUPPORT ISOLD TSRA WITH DIURNAL HEATING.
THUS...HAVE REINTRODUCED THE MENTION OF TSRA ALONG OUR WESTERN
BORDER. EASTERN AREAS SHOULD REMAIN TOO STABLE/COOL TO SUPPORT
TSRA THROUGH THE SHORT TERM. HAVE NOT INCLUDED ANY MENTION OF DZ
THIS PERIOD AS WITH -RA LIKELY...IT JUST ADDS CONFUSION TO THE
PUBLIC FORECAST. TEMPERATURES WILL BE UNSEASONABLY COOL THROUGH
THE PERIOD WITH HIGHS IN THE 50S SUN ACROSS MUCH OF THE
REGION...EXCEPT THE PERIPHERY OF THE CWA WHERE IT WILL BE IN THE
60S. HAVE LEANED HEAVILY TOWARD THE MUCH COOLER ECMWF MOS THROUGH
THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
CONSIDERABLE QUESTIONS REMAIN WITH RESPECT TO THE EVOLUTION OF
WEATHER FEATURES WITH THE EXTENDED PERIODS...ESPECIALLY THE LATER
PERIODS. THE BIG QUESTION...AS HAS BEEN THE CASE FOR DAYS NOW...IS
THE DEVELOPMENT/MOVEMENT/POSITION OF A POTENTIAL CLOSED UPPER LOW.
ECMWF/GFS CONTINUE TO COVER THE ENTIRE SPECTRUM WITH RESPECT TO
THE DETAILS. THUS...THERE IS LITTLE TO NO RELIABILITY OR
CONFIDENCE IN THE EXTENDED FORECAST...ESPECIALLY THE LATER
PERIODS. AT THE BEGINNING OF THE EXTENDED PERIODS...TUE-
WED...STILL DEALING WITH A LINGERING WEDGE ACROSS THE EASTERN
SECTIONS. GIVEN THE PERSISTENT PATTERN THIS PAST WINTER AND SPRING
SO FAR...HAVE LEANED HEAVILY TOWARD THE ECMWF WHICH IS MUCH SLOWER
TO ERODE THE WEDGE. BETTER PCPN CHANCES WITH BOTH THE GFS/ECMWF
SHIFT SOUTH AND EAST OF THE CWA EARLY...WITH PCPN TRENDING TOWARD
A MORE DIURNAL PATTERN FOCUSING ALONG THE MOUNTAINS IN AREAS OF
BETTER DIFFERENTIAL HEATING. TEMPERATURES SHOULD SLOWLY WARM
TOWARD MORE SEASONAL LEVELS...BUT LIKELY WILL REMAIN JUST BELOW
NORMAL THROUGH THE NEW RIVER VALLEY...SHENANDOAH VALLEY...AND
GREENBRIER VALLEY. DURING THE FINAL DAYS OF THE EXTENDED...NAMELY
THU-FRI...HAVE GONE NEARLY ENTIRELY WITH THE 00Z/12Z ECMWF
SOLUTION AND COMPLETELY IGNORED THE GFS SOLUTION OF A VERY DEEP
CLOSED LOW THROUGH THE SOUTHERN ABLUTIONS WITH ATTENDANT HEAVY
RAIN FOLLOWED BY SNOW AND RIDICULOUSLY COLD TEMPERATURES FOR
EARLY MAY. THE ECMWF OFFERS A MUCH MORE PLAUSIBLE FORECAST FROM
ALL ASPECTS...QPF...POPS...AND TEMPS. A COLD FRONT ON THE FORWARD
FLANK OF ANY LOW PRESSURE AREA ACROSS THE UPPER MID-WEST/OH VALLEY
MAY BEGIN TO APPROACH THE AREA BY SAT WITH INCREASING CHANCES OF
SHRA/TSRA AT THAT TIME.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 140 AM EDT SATURDAY...
CEILINGS WILL GRADUALLY LOWER THROUGHOUT THE DAY. DO NOT EXPECT
MVFR CEILINGS UNTIL WELL AFTER 00Z/8PM THIS EVENING. AS LOW
PRESSURE MOVES ACROSS THE SOUTHERN MISSISSIPPI VALLEY...FORCING
AND INFLOW OF MOISTURE OVER THE SOUTHERN APPALACHIANS WILL GREATLY
INCREASE. RAIN WILL OVERSPREAD THE AREA BEFORE 12Z/8AM SUNDAY.
THIS SHOULD RESULT IN MVFR/IFR CIGS AND VSBYS...ESPECIALLY IN THE
MOUNTAINS DUE TO LIGHT TO MODERATE RAIN.
FLYING WEATHER WILL REMAIN POOR FOR THE NEXT SEVERAL DAYS. SURFACE LOW
PRESSURE WILL MOVE OUT OF THE PLAINS AND INTO THE OHIO VALLEY...
WEAKENING AS IT GOES. NET RESULT WILL BE MOIST SOUTH FLOW AND
PERIODS OF PCPN...LOW CLOUDS AND SUB VFR VISIBILITIES OVER THE
AREA THROUGH MONDAY. HIGH PRESSURE WILL THEN WEDGE DOWN THE ERN
SEABOARD FOR TUESDAY AS A STRONG COLD FRONT APPROACHES ON
WEDNESDAY. MVFR WITH PERIODS OF IF ARE LIKELY FOR MUCH OF NEXT
WEEK.
&&
.EQUIPMENT...
OBSERVATION FROM AUTOMATED EQUIPMENT AT THE VIRGINIA TECH
AIRPORT...KBCB...WAS EXPERIENCING COMMUNICATION PROBLEMS. THIS
OBSERVATION WILL BE UNAVAILABLE UNTIL FURTHER NOTICE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/RAB
NEAR TERM...JH/KK
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...AMS
EQUIPMENT...AMS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
144 AM EDT SAT APR 27 2013
.SYNOPSIS...
HIGH PRESSURE ACROSS THE REGION TONIGHT WILL DRIFT OFF THE MID-
ATLANTIC COAST AS AN UPPER DISTURBANCE MOVES EAST FROM THE MID-
MISSISSIPPI VALLEY INTO THE SOUTHERN APPALACHIANS. THIS SYSTEM
WILL SLOW AND LINGER ACROSS THE REGION THROUGH THE MID-PART OF
NEXT WEEK...KEEPING CLOUDS...LIGHT RAIN...AND UNSEASONABLY COOL
TEMPERATURES IN PLACE. A NEW WEATHER SYSTEM WILL APPROACH FROM THE
WEST BY THE END OF NEXT WEEK WITH MORE SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 840 PM EDT FRIDAY...
SOUNDINGS SHOW VERY DRY AIR CONTINUING ESPCLY IN THE LOWER LEVELS
THIS EVENING WITH MOST ADVECTION OF MOISTURE COMING FROM THE WEST
ATTM. THIS DRY AIR HAS BASICALLY DRIED UP THE INITIAL BATCH OF
PRECIP HEADING IN FROM THE WEST WITH THE FIRST FAINT WAVE...WHILE
HAVE ANOTHER WEAK ARC OF ENERGY SET TO ARRIVE FROM TN/KY OVER THE
FAR WEST LATE. LATEST RAP PICKS UP ON THIS AFTER MIDNIGHT AND HAS
SOME SPOTTY -RA OVER THE NW NC RIDGES...AND AREAS WEST OF I-77 IN
VA LATE. MOST OTHER SHORT TERM GUIDANCE QUITE DRY SO ONLY
INCLUDING A SLIGHT POP FOR VERY -RA EXTREME SW BY DAWN. OTRW WILL
SEE VARYING AMOUNTS OF HIGH/MID CLOUDS...WITH A THICKER MID DECK
CANOPY DEVELOPING OVERNIGHT WEST...AND SOME THIN SPOTS OVER THE
NORTH/EAST. BUMPED UP LOW TEMPS A BIT SW DUE TO THICKER CLOUDS
WITH MOST SPOTS IN THE 40S BY MORNING...EXCEPT SOME 30S DEEPER
VALLEYS ACROSS THE NORTH.
HIGH PRESSURE WILL MOVE EAST OFF THE NEW ENGLAND COAST ON SATURDAY.
AN APPROACHING SHORTWAVE COMBINED WITH EASTERLY FLOW WILL INCREASE
MOISTURE ACROSS OUR REGION SATURDAY. PLACED THE HIGHEST POPS ON
SATURDAY ALONG THE SOUTHERN BLUE RIDGE MOUNTAINS...WITH LIGHTER
CHANCES IN THE EAST. HIGH SATURDAY VARY FROM THE LOW 50S ACROSS THE
SOUTHWEST MOUNTAINS TO AROUND 70 IN THE PIEDMONT. A FASTER SPREAD OF
MOISTURE COULD TRIM HIGHS SATURDAY MORE WITH ADDITIONAL CLOUD COVER
AND RAIN.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 345 PM EDT FRIDAY...
ECMWF/GFS IN GENERAL AGREEMENT ON THE EVOLUTION OF THE PATTERN
SUN THROUGH MON...BUT CONTINUE TO DIFFER ON TIMING. HOWEVER...MOST
OF THE TIMING ISSUES APPEAR TO BE RESOLVED BY THE BEGINNING OF THE
SHORT TERM PERIOD. THIS PERIOD CAN BEST BE CHARACTERIZED AS A
RATHER CONTINUOUS PERIOD OF LIGHT RAIN AS A SOUTHERN STREAM
DISTURBANCE SPREADS THROUGH THE REGION IN A FAVORABLE WEDGE AREA.
THE WEDGE WILL BE ENHANCED/REINFORCED AS THE PCPN FALLS INTO AN
INITIALLY DRY/COOL SFC AIR MASS. QPF THROUGH THE PERIOD SHOULD
RANGE FROM 0.25 INCH IN THE NE PART OF THE CWA TO PERHAPS NEAR AN
INCH IN THE NW NC MOUNTAINS AND FAR SW VA. BY SUN AFTERNOON...THE
WEDGE MAY ERODE ENOUGH ALONG THE WESTERN EDGE...FROM MERCER COUNTY
WV DOWN TOWARD NE TN TO SUPPORT ISOLD TSRA WITH DIURNAL HEATING.
THUS...HAVE REINTRODUCED THE MENTION OF TSRA ALONG OUR WESTERN
BORDER. EASTERN AREAS SHOULD REMAIN TOO STABLE/COOL TO SUPPORT
TSRA THROUGH THE SHORT TERM. HAVE NOT INCLUDED ANY MENTION OF DZ
THIS PERIOD AS WITH -RA LIKELY...IT JUST ADDS CONFUSION TO THE
PUBLIC FORECAST. TEMPERATURES WILL BE UNSEASONABLY COOL THROUGH
THE PERIOD WITH HIGHS IN THE 50S SUN ACROSS MUCH OF THE
REGION...EXCEPT THE PERIPHERY OF THE CWA WHERE IT WILL BE IN THE
60S. HAVE LEANED HEAVILY TOWARD THE MUCH COOLER ECMWF MOS THROUGH
THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
CONSIDERABLE QUESTIONS REMAIN WITH RESPECT TO THE EVOLUTION OF
WEATHER FEATURES WITH THE EXTENDED PERIODS...ESPECIALLY THE LATER
PERIODS. THE BIG QUESTION...AS HAS BEEN THE CASE FOR DAYS NOW...IS
THE DEVELOPMENT/MOVEMENT/POSITION OF A POTENTIAL CLOSED UPPER LOW.
ECMWF/GFS CONTINUE TO COVER THE ENTIRE SPECTRUM WITH RESPECT TO
THE DETAILS. THUS...THERE IS LITTLE TO NO RELIABILITY OR
CONFIDENCE IN THE EXTENDED FORECAST...ESPECIALLY THE LATER
PERIODS. AT THE BEGINNING OF THE EXTENDED PERIODS...TUE-
WED...STILL DEALING WITH A LINGERING WEDGE ACROSS THE EASTERN
SECTIONS. GIVEN THE PERSISTENT PATTERN THIS PAST WINTER AND SPRING
SO FAR...HAVE LEANED HEAVILY TOWARD THE ECMWF WHICH IS MUCH SLOWER
TO ERODE THE WEDGE. BETTER PCPN CHANCES WITH BOTH THE GFS/ECMWF
SHIFT SOUTH AND EAST OF THE CWA EARLY...WITH PCPN TRENDING TOWARD
A MORE DIURNAL PATTERN FOCUSING ALONG THE MOUNTAINS IN AREAS OF
BETTER DIFFERENTIAL HEATING. TEMPERATURES SHOULD SLOWLY WARM
TOWARD MORE SEASONAL LEVELS...BUT LIKELY WILL REMAIN JUST BELOW
NORMAL THROUGH THE NEW RIVER VALLEY...SHENANDOAH VALLEY...AND
GREENBRIER VALLEY. DURING THE FINAL DAYS OF THE EXTENDED...NAMELY
THU-FRI...HAVE GONE NEARLY ENTIRELY WITH THE 00Z/12Z ECMWF
SOLUTION AND COMPLETELY IGNORED THE GFS SOLUTION OF A VERY DEEP
CLOSED LOW THROUGH THE SOUTHERN ABLUTIONS WITH ATTENDANT HEAVY
RAIN FOLLOWED BY SNOW AND RIDICULOUSLY COLD TEMPERATURES FOR
EARLY MAY. THE ECMWF OFFERS A MUCH MORE PLAUSIBLE FORECAST FROM
ALL ASPECTS...QPF...POPS...AND TEMPS. A COLD FRONT ON THE FORWARD
FLANK OF ANY LOW PRESSURE AREA ACROSS THE UPPER MID-WEST/OH VALLEY
MAY BEGIN TO APPROACH THE AREA BY SAT WITH INCREASING CHANCES OF
SHRA/TSRA AT THAT TIME.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 140 AM EDT SATURDAY...
CEILINGS WILL GRADUALLY LOWER THROUGHOUT THE DAY. DO NOT EXPECT
MVFR CEILINGS UNTIL WELL AFTER 00Z/8PM THIS EVENING. AS LOW
PRESSURE MOVES ACROSS THE SOUTHERN MISSISSIPPI VALLEY...FORCING
AND INFLOW OF MOISTURE OVER THE SOUTHERN APPALACHIANS WILL GREATLY
INCREASE. RAIN WILL OVERSPREAD THE AREA BEFORE 12Z/8AM SUNDAY.
THIS SHOULD RESULT IN MVFR/IFR CIGS AND VSBYS...ESPECIALLY IN THE
MOUNTAINS DUE TO LIGHT TO MODERATE RAIN.
FLYING WEATHER WILL REMAIN POOR FOR THE NEXT SEVERAL DAYS. SURFACE LOW
PRESSURE WILL MOVE OUT OF THE PLAINS AND INTO THE OHIO VALLEY...
WEAKENING AS IT GOES. NET RESULT WILL BE MOIST SOUTH FLOW AND
PERIODS OF PCPN...LOW CLOUDS AND SUB VFR VISIBILITIES OVER THE
AREA THROUGH MONDAY. HIGH PRESSURE WILL THEN WEDGE DOWN THE ERN
SEABOARD FOR TUESDAY AS A STRONG COLD FRONT APPROACHES ON
WEDNESDAY. MVFR WITH PERIODS OF IF ARE LIKELY FOR MUCH OF NEXT
WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/RAB
NEAR TERM...JH/KK
SHORT TERM...RAB
LONG TERM...RAB
AVIATION...AMS
AREA FORECAST DISCUSSION
NWS SPOKANE WA
234 PM PDT Sat Apr 27 2013
.SYNOPSIS...
An upper level low pressure system passing through the region
tonight will bring scattered showers along the Cascade crest and
over the Central Panhandle Mountains. Another storm system is
expected Sunday night into Monday and will bring a better chance
for some rain and mountain snow along with stronger winds for
Monday afternoon. This system will usher in much cooler
temperatures for early next week. High pressure will then rebound,
bringing a warming trend for the middle to end of next week.
&&
.DISCUSSION...
Tonight: A cold front is beginning to sag into the region from the
northwest. Water vapor imagery shows a nicely defined dry slot
indicating the back edge of the front from Castlegar in BC to 50
N 160 W in the Gulf of Alaska. A fetch of Pacific moisture is
streaming eastward into the Northwest along the leading edge of
the front and is expected to sag southward with time tonight. This
moisture has generally only yielded some rain across western
Washington up to the crest of the Cascade Mountain Range. Over
eastern WA into the ID Panhandle, we have been too dry for any of
this moisture to reach the surface yet. However, LAPS data has
shown a gradual moistening of the upper atmosphere through time
today, and radar has begin to show some blips to the east and
south of Spokane. We should hold on to a fairly substantial pocket
of dry air through tonight across the basin. Strong westerly flow
across the Cascades will undoubtedly result in conditions
remaining dry east for the western two-thirds of the forecast area
(expect right along the Cascade crest). Eventually we will begin
to see some rain reaching the surface late this afternoon or early
evening. Latest HRRR model guidance suggest that measurable
rainfall will begin in the Central Panhandle Mountains around 6:00
PM or so. Gusty winds across the Wenatchee Area over into the
western portions of the basin are expected to relax this evening
as we begin to decouple a bit from the free atmosphere. I fully
anticipate our Wind Advisory to be able to come down right around
sunset today. /SVH
...BREEZY SUNDAY THEN VERY WINDY ON MONDAY...
Sunday through Monday night: Wind will be the main concern for
the next couple of days as a swift westerly flow remains parked
over the Inland Northwest, along with mostly dry and cool weather.
With a surface low over the Canadian Rockies and a surface high
on the OR coast, a stiff pressure gradient will continue into
Sunday with good mixing kicking up winds in the afternoon and
early evening. Speeds should be similar if not slightly lighter
than experienced today with lack of a frontal boundary. The NAM
and SREF want to hold on to low level moisture across southeast
Washington into the Idaho Sunday morning and given the light
upslope lift, could see light showers across the Palouse, Blue
mountains and into the Idaho panhandle. Anticipate light
orographic showers to persist into the afternoon and evening in
north Idaho. Then late Sunday night, the upper level jet stream
sinks over the region while the next in a series of weather
disturbances drops into eastern Washington. There is a chance of
precipitation, although it will be small and confined to the
orographic favored areas of the Cascade crest, the Blue mountains
and parts of north Idaho. As this features pushes through the
region, winds will steadily increase due the cold and dry air
advection. The jet 120 kt jet core will be over the region by
midday Monday. This will support stronger winds mixing to the
surface and also kicking up some blowing dust. There is also the
potential for mountain wave winds off the lee side of the
Cascades. The GFS MAV seems to have the strongest winds with this
feature, supporting the idea for the potential of high wind
highlights for a good chunk of the forecast area. The NAM MET is
slightly weaker but it still shows windy conditions across the
region. Have bumped up the winds in the forecast for Monday and
will continue to highlight the concern in the Hazardous Weather
Outlook. By Monday night, drier air filters in the region with
clearing skies and winds decrease. Dewpoints take a plunge and
drop into the 20s. In sheltered areas, there is the potential for
some rather chilly freezing temperatures by late Monday night.
/rfox.
Tues to Thu night: After a few showers and breezy conditions,
high pressure brings drier weather by mid-week. Tuesday a surface
trof lingers across N ID and the E 1/3 of WA. A secondary mid-
level shortwave slides by on 130kt+ jet. The jet curves by the
Cascades through north Oregon early, placing some unstable lapse
rates, marginal CAPE (50-200 J/kg) and LI values across NE WA and
N ID. These ingredients will be working against CIN and larger-
scale subsidence with the approaching high. The forecast focuses
the primary shower threat across Idaho in mountains in the
afternoon. Ingredients are marginal for thunder so I kept it out
for now, but I would not be surprised to see some "one-clap-
wonders". I expect locally breezy conditions to continue. However
winds should be much less as compared to the days just prior.
Tuesday night to Thursday night high pressure builds in and, for
the most part, the atmosphere stabilizes with drier, clearer
conditions. A weak impulse approaches late Thursday with a few
more clouds. The threat of precipitation will be minimal.
Temperatures remain cooler than normal on Tuesday, with more
freezing temperatures possible Wednesday morning, but value
moderate toward average by Thursday. /J. Cote`
Friday through Saturday night...The Inland Northwest will be
on the eastern edge of an upper level ridge centered off the
Pacific coast. Weather-wise, this might be the first Saturday that
the weather looks fairly uneventful. The winds do not look like
they will be much of an issue, and precipitation chances will be
limited to the higher elevations of the Idaho panhandle and the
Cascades. Well above normal temperatures are forecast for both.
Friday and Saturday. ty
&&
.AVIATION...
18Z TAFS: A cold front approaching the region from the northwest
has resulted in increasing mid and high level clouds. these clouds
will lower a bit to between 5-8k ft through the afternoon into the
evening as the atmosphere moistens from the top down. Pre-frontal
southwesterly winds will increase this afternoon with gusts up
around 30-35 mph over much of the region. These winds will likely
kick up some dust across the northern Columbia Basin, which may
result in some reduced visibilities at KMWH. We may see some
showers developing in the vicinity of KCOE and KPUW this evening,
but all other TAF sites are expected to remain dry. Models are
indicating the possibility for some low stratus developing near
these TAF sites early Sunday morning, but I don`t have a lot of
confidence with this as boundary layer moisture will be lacking
without much rainfall anticipated with the cold front. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 43 63 43 56 32 53 / 10 10 30 10 0 10
Coeur d`Alene 41 62 40 55 30 52 / 20 20 40 20 10 20
Pullman 41 61 43 54 29 51 / 20 20 30 20 10 20
Lewiston 50 68 48 62 38 57 / 10 10 20 10 10 20
Colville 40 67 42 58 31 58 / 10 10 30 10 0 20
Sandpoint 39 61 39 54 31 50 / 30 20 70 30 10 20
Kellogg 42 59 41 49 31 45 / 60 30 70 70 20 30
Moses Lake 47 70 46 63 33 63 / 0 0 10 0 0 0
Wenatchee 48 66 46 59 37 58 / 0 10 10 0 0 0
Omak 40 68 42 58 32 59 / 0 10 10 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...Wind Advisory until 8 PM PDT this evening for Moses Lake Area-
Upper Columbia Basin-Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 PM CDT SUN APR 28 2013
.UPDATE...
ISSUED AT 558 PM CDT SUN APR 28 2013
CURRENTLY A NARROW LINE OF CONVECTION HAS INITIATED ALONG THE COLD
FRONT IN MINNESOTA FROM RUSH CITY TO MINNEAPOLIS AND ST JAMES.
LAPS ANALYSIS SHOWED MLCAPE VALUES OF 250-600 J/KG...MOSTLY RIGHT
ALONG THE FRONT. KMPX RADAR IMAGERY DOES SUGGEST THAT THE LINE OF
CONVECTION MAY HAVE JUMPED OFF THE FRONT RECENTLY...THOUGH.
MEANWHILE...OVER THE FORECAST AREA...SOME RIDGING HAS BUILT IN
ALOFT PER RAP ANALYSIS...HELPING TO CLEAR SKIES OUT.
PRECIPITATION CHANCES CONTINUE TO BE THE FOCUS TONIGHT. THE
28.12Z REGIONAL CANADIAN AND 28.19/20/21Z HRRR RUNS HAVE BEEN
DOING A GREAT JOB WITH THE CONVECTION ON THE FRONT. ALL OF THESE
MODELS SUGGEST A WEAKENING TREND AS THEY PUSH EAST THROUGH THE
EVENING. THIS MAKES SENSE AS THEY SEEM TO BE DIURNALLY ASSISTED
WITH THE CAPE THAT BUILT AHEAD OF THE FRONT. ONCE DIURNAL COOLING
TAKES PLACE...INSTABILITY WILL WANE AND THUS THE STORMS AS WELL.
PERHAPS A FEW MAY MAKE IT INTO NORTHWEST SECTIONS OF THE FORECAST
AREA...ENOUGH TO WARRANT 20-30 PERCENT CHANCES...LOWER THAN THE
PREVIOUS FORECAST. SEEING SOME OF THE CONVECTION JUMPING OFF THE
FRONT ALSO IS WORRISOME TO HOLD IT TOGETHER BECAUSE INSTABILITY
WANES PRETTY QUICK. THERE COULD BE A GENERALLY DRY PERIOD THEN
UNTIL LATE IN THE NIGHT...WHICH IS WHEN THE COLD FRONT SLIDES INTO
THE AREA. BEHIND THIS FRONT...TWO FORCING MECHANISMS SHOULD HELP
DEVELOP PRECIPITATION...
1. A SHORTWAVE OVER NORTHWEST WYOMING PUSHING EAST INTO EASTERN
SOUTH DAKOTA BY LATE IN THE NIGHT...YIELDING SOME DPVA DOWNSTREAM
INTO NORTHERN IOWA AND SOUTHERN MINNESOTA.
2. MID-LEVEL FRONTOGENESIS IN PLACE BEHIND THE FRONT. RADAR SHOWS
THIS FRONTOGENESIS ALREADY BY A BAND OF SHOWERS FROM NEAR ABERDEEN
SOUTH DAKOTA TO DULUTH MN.
THUS STILL HAVE KEPT SOME HIGHER PRECIPITATION CHANCES FOR LATE IN
THE NIGHT INTO MONDAY MORNING...ESPECIALLY OVER NORTHEAST IOWA
WHERE CONSENSUS EXISTS FROM ALL MODELS FOR PRECIPITATION TO OCCUR.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013
THE MAIN FOCUS FOR TONIGHT INTO MONDAY IS WITH A TWO TIERED SYSTEM
AND THE PRECIPITATION CHANCES THAT COME ALONG WITH IT. THE FIRST
WAVE APPROACHES THE REGION THIS EVENING IN THE FORM OF A SURFACE
COLD FRONT THAT IS CURRENTLY ANALYZED IN WESTERN MINNESOTA. MUCH
OF THE 28.12Z GUIDANCE ARE FORECASTING TOO HIGH OF SURFACE DEW
POINTS...IN THE LOW TO MID 50S WHEN CURRENT OBS SHOW MID
40S...WHICH IN TURN IS MAKING THE INSTABILITY IN THESE MODELS TOO
HIGH. THIS IS CAUSING A LOT OF THE GUIDANCE TO COME UP WITH A
LARGE AREA OF CONVECTION THAT DEVELOPS THIS EVENING AHEAD OF THE
FRONT AND BRINGS IT THROUGH THE REGION IN AN DIMINISHING FASHION
AS THE INSTABILITY WANES OVERNIGHT. THAT TREND IS OKAY...BUT AM
NOT VERY CONFIDENT THAT THIS CONVECTION WILL BE AS WIDESPREAD AS
GUIDANCE SUGGESTS. THE 28.12Z ARW EAST/WEST MODELS SEEM TO DO THE
BEST JOB AT LIMITING THE CLIMBING DEW POINTS AND KEEP 0-3KM MUCAPE
IN THE 200-400 J/KG RANGE OVERNIGHT AND MATCHES BEST TO THESE
THOUGHTS OF MORE SCATTERED THAN WIDESPREAD CONVECTION OVERNIGHT.
WITH JUST A FEW HUNDRED J/KG OF CAPE TO WORK WITH...HAVE LIMITED
THE THUNDER COVERAGE TO BEING ISOLATED TONIGHT. THERE IS SOME
INCREASING MID LEVEL WINDS AS THIS FRONT APPROACHES...SO SHEAR MAY
BE DECENT ENOUGH THAT...COMBINED WITH SOME LOW FREEZING
LEVELS...THERE COULD BE SOME SMALL HAIL THAT OCCURS WITH A FEW OF
THE STORMS BUT NOTHING THAT WOULD BE CONSIDERED SEVERE.
THE MAIN MID LEVEL TROUGH DIVES DOWN ACROSS THE REGION TOMORROW
MORNING AND IS EXPECTED TO DEVELOP A MORE WIDESPREAD AREA OF
CONVECTION ALONG THE WEAKENING SURFACE FRONT. THIS MID LEVEL
TROUGH IS CURRENTLY NOTED ON GOES WATER VAPOR IMAGERY EXTENDING
EAST TO WEST FROM SOUTHWEST ONTARIO INTO SOUTHEAST MONTANA. AS
THIS TROUGH SAGS SOUTHEAST TOMORROW...SOME DIFFERENCES ARISE
BETWEEN THE 28.12Z MESO AND SYNOPTIC SCALE MODELS. THE 28.12Z
NAM/GFS/ECMWF/GEM ALL SHOW SOME STRONG LOW LEVEL MOISTURE
TRANSPORT NOSING UP INTO EASTERN IOWA BY LATE MORNING THAT ALSO
BRING SURFACE DEW POINTS UP INTO THE 60S AHEAD OF THE SURFACE/LOW
LEVEL LOW. THIS BRINGS SFC/0-3KM MUCAPE UP TO ABOVE 2000 J/KG AND
DEVELOPS A WIDESPREAD AREA OF CONVECTION ALONG THE NOSE OF THE LOW
LEVEL JET. MEANWHILE...28.12Z ARW/NMM ARE MUCH MORE TAME WITH THE
MOISTURE RETURN/DEW POINTS/INSTABILITY AND CONVECTIVE DEVELOPMENT.
HAVE KEPT THE LIKELY PRECIPITATION CHANCES GOING FOR NORTHEAST
IOWA/SOUTHWEST WISCONSIN TOMORROW WHERE THIS CONVECTION IS A BIT
MORE CERTAIN...BUT THINK THAT THE SYNOPTIC MODELS ARE A TAD
OVERDONE. IF THE MOISTURE RETURN CAN DEVELOP AS ADVERTISED ON
THESE SYNOPTIC MODELS...WILL HAVE TO WATCH FOR A BRIEF PERIOD OF
SEVERE STORMS THAT COULD PRODUCE SOME LARGE HAIL/GUSTY WINDS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013
THE 28.12Z GUIDANCE REMAINS STUBBORN WITH NO DIFFERING TRENDS
NOTED BETWEEN THIS RUN AND THE 28.00Z RUN FOR A COLD FRONT THAT
WILL MOVE THROUGH ON TUESDAY. AHEAD OF THIS FRONT
ON MONDAY NIGHT...THE LOW LEVEL JET/MOISTURE TRANSPORT WILL PUSH
BACK TO THE NORTH AHEAD OF THE FRONT AND COULD SPARK OFF SOME
CONVECTION AS IT LIFTS NORTHWARD. FOR TUESDAY...THE 28.12Z ECMWF
REMAINS THE SLOW OUTLIER WITH THE EASTWARD PROGRESSION OF THE
SURFACE COLD FRONT ON TUESDAY AND PRESENTS THE WARMEST SOLUTION
FOR TEMPERATURES. BY 00Z WEDNESDAY...THE 28.12Z NAM/GFS BOTH HAVE
THIS FRONT INTO NORTHWEST ILLINOIS WHILE THE ECMWF STILL HAS IT
BACK IN NORTHWEST WISCONSIN/JUST CLEARING SOUTHEAST MINNESOTA.
WITH LOW LEVEL MOISTURE TRANSPORT INCREASING AHEAD OF THIS FRONT
ON TUESDAY AND DECENT LOW LEVEL LIFT ALONG THE FRONT...SOME SEVERE
WEATHER IS POSSIBLE IN THE WARM SECTOR TUESDAY. WHERE THAT WARM
SECTOR IS ALIGNED BY MID AFTERNOON IS UNCERTAIN STILL...BUT WILL
HAVE TO WATCH FOR WHICH WAY THIS FRONT TRENDS. DUE TO THERE NOT
BEING MUCH IN THE WAY OF CHANGES IN THE GUIDANCE...HAVE NOT MADE
MANY ADJUSTMENTS TO THE GOING FORECAST OVER THIS PERIOD.
AFTER THIS COLD FRONT MOVES THROUGH BY TUESDAY NIGHT IT WILL THEN
STALL OUT TO THE EAST OF THE REGION AS A MID TO UPPER LEVEL TROUGH
AMPLIFIES ACROSS THE CENTRAL US TOWARD THE MIDDLE OF THE WEEK.
THIS TROUGH GETS CUT OFF FROM THE FLOW WITH THE CORE OF THE LOW
SITTING RIGHT OVER THE UPPER MISSISSIPPI RIVER VALLEY THROUGH NEXT
WEEKEND. STRONG FORCING WILL DEVELOP ON WEDNESDAY IN RESPONSE TO
A STRENGTHENING LOW TO MID LEVEL BAND OF FRONTOGENESIS THAT FORMS
TO THE WEST OF THE SURFACE FRONT. WHILE THE 28.12Z ECMWF CONTINUES
TO BE AN OUTLIER WITH A WARMER SOLUTION FROM 700MB DOWN TO THE
SURFACE ON WEDNESDAY AND WANTS TO KEEP THE PRECIPITATION AS
MAINLY RAIN TO BEGIN...IT DOES APPEAR TO BE COMING AROUND TO BEING
COLD ENOUGH TO PRODUCE ALL SNOW FROM WEDNESDAY NIGHT INTO EARLY
THURSDAY. THIS IS ESPECIALLY THE CASE ACROSS SOUTHEAST MINNESOTA
AND NORTHEAST IOWA WHERE SOME SIGNIFICANT SNOW RATES AND
ACCUMULATIONS ARE POSSIBLE. 28.12Z GFS THERMAL PROFILES SHOW THAT
THE MAIN QUESTION IS WITH SURFACE TEMPERATURES AND HOW MUCH THEY
WILL COOL AS THE PRECIPITATION COMMENCES ON WEDNESDAY. THE HIGHEST
CONFIDENCE FOR ANY SNOW ACCUMULATION AT THIS POINT IS WEDNESDAY
NIGHT INTO THURSDAY MORNING AS THE COLDEST LOW LEVEL AIR COMES IN.
CURRENT FORECAST TEMPERATURES FOR WEDNESDAY INTO THURSDAY MAY END
UP BEING TOO HIGH...BUT FOR NOW HAVE DONE A SEMI-BLEND OF THE
28.12Z GFS/ECMWF.
BEYOND THIS FEATURE...THE 28.12Z GFS IS FASTER WITH CLEARING OUT
THE PRECIPITATION ON THURSDAY COMPARED TO THE ECMWF AND GEM WHICH
LINGER THE FRONTOGENETIC BAND OVER THE REGION THROUGH THE REST OF
THE WEEK AS THE MID LEVEL LOW GETS CUT OFF FROM THE FLOW. THIS MID
LEVEL AND SURFACE LOW RETROGRADE BACK INTO IOWA/MISSOURI BY NEXT
WEEKEND...WHICH MAY HELP TO BRING SOME SLIGHTLY WARMER AIR BACK
INTO THE REGION. OVERALL...EXPECTING PERIODS OF PRECIPITATION AS
THIS LOW SITS AND SPINS WITH SHORTWAVE TROUGHS ROTATING AROUND IT
THROUGH NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 630 PM CDT SUN APR 28 2013
A COUPLE OF ITEMS OF INTEREST FOR THE AVIATION PERIOD. FIRST IS
THE ONGOING SHOWERS AND A FEW THUNDERSTORMS ALONG A COLD FRONT
STRETCHING FROM MINNEAPOLIS INTO NORTHWEST IOWA. THIS
PRECIPITATION WAS INITIATED BECAUSE OF TEMPERATURES CLIMBING INTO
THE 80S. ONCE TEMPERATURES COOL WITH SUNSET...THINKING THESE
SHOWERS WILL DIMINISH. DID KEEP A VCSH BETWEEN 03-05Z AT KRST IN
THE EVENT THEY CAN SURVIVE TO KRST...WITH THE TIMING BASED ON
EXTRAPOLATION. 10-15 KT SOUTHERLY WINDS AT KRST WILL SWING AROUND
TO THE NORTHWEST WITH THE FRONTAL PASSAGE...AND DECREASE DUE TO
DAYTIME MIXING ENDING. NEXT ITEM OF INTEREST IS A LOW PRESSURE
TROUGH PROGGED TO SLIDE ACROSS THE TAF SITES LATE TONIGHT INTO THE
DAY MONDAY. THERE REMAINS A STRONG SIGNAL FOR SHOWERS AND
POSSIBLY A FEW THUNDERSTORMS TO OCCUR WITH THIS TROUGH...BUT
TIMING AND WHETHER OR NOT THE TAF SITES ARE AFFECTED REMAINS
UNCERTAIN. THEY COULD ENTIRELY STAY TO THE SOUTH. FOR NOW JUST
PLACED A VCSH AT KRST BETWEEN 11-15Z AND 10-21Z AT KLSE. WILL TRY
TO REFINE THE TIMING AND WHETHER OR NOT THE SITES ARE AFFECTED
WITH THE 06Z TAF ISSUANCE.
REGARDING CEILINGS AND VISIBILITIES...GIVEN THAT A LOT OF
UNCERTAINTY EXISTS ON WHETHER ANY PRECIPITATION REACHES THE TAF
SITES...KEPT CONDITIONS VFR AT THIS TIME. ADDITIONALLY...THERE ARE
NO OBSERVATIONS REPORTING LESS THAN VFR AS OF 23Z...EVEN UNDER THE
BAND OF SHOWERS. PLENTY OF ALTOSTRATUS CLOUDS COMING ACROSS SHOULD
ALSO HELP PREVENT ANY BR/FOG FORMATION LATE TONIGHT.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT SUN APR 28 2013
POTENTIAL EXISTS FOR SOME HEAVY RAINFALL THIS WEEK AS A SYSTEM
STALLS OUT ACROSS THE REGION TOWARD MID WEEK. THERE IS SOME
QUESTION ABOUT WHAT THE PRECIPITATION TYPE WILL BE...BUT THE
FORECAST GUIDANCE IS SUGGESTING RAINFALL AMOUNTS OF OVER AN INCH
BY THE END OF THE WEEK. SHOULD THIS PRECIPITATION FALLS AS
RAIN...THERE COULD BE AN INCREASE IN LOCAL RIVER LEVELS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS NEW YORK NY
527 AM EDT MON APR 29 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN ANCHORED FROM THE CANADIAN MARITIMES
THROUGH THE NEW ENGLAND COAST THROUGH THE WEEKEND...WHILE WEAK LOW
PRESSURE PASSES TO THE SOUTH ACROSS THE MID ATLANTIC STATES
TODAY AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAIN ASSOCIATED WITH WEAKENING MID LEVEL SHORTWAVE HAS MOVED INTO
WESTERN ZONES...AND IS MAKING SLOW PROGRESS EASTWARD DUE TO
DOWNSTREAM RIDGING AND SUBSIDENCE. DECREASE POPS TO CHC ACROSS
INTERIOR LOWER HUDSON VALLEY LOCATIONS AS LATEST RADAR TRENDS AND
MODEL GUIDANCE INDICATE THAT IT SHOULD BE MORE SCATTERED IN NATURE
FROM HERE ON OUT. SFC HIGH OFF THE NEW ENGLAND COAST IS EXPECTED
TO LIFT A BIT TO THE NORTH TODAY WHICH WILL ALLOW THE RAIN TO
GRADUALLY SPREAD EASTWARD. TOUGH PART OF THE FORECAST IS HOW FAR
THE PCPN GETS AND WHEN THE DRIER AIR ASSOCIATED WITH THE HIGH
BUILDS BACK IN SHUNTING IT TO THE S AND W. GFS IS AGGRESSIVE
BRINGING THE DRY AIR BACK BY AFTN AND KEEPING ALL PCPN S AND W OF
THE FORECAST AREA THROUGH TUE. MOST OF THE OTHER MODEL GUIDANCE
HOLDS ON TO IT THROUGH AT LEAST THIS EVE. MOST OF THE GUIDANCE WAS
TOO SLOW BRINGING THE PCPN INTO NE NJ AND THE LOWER HUDSON VALLEY
INCLUDING THE WRFNMM/WRFARW AND RUC. THE HRRR HAS BEEN HANDLING
THE SITUATION WELL AND KEEPS PCPN THROUGH THE DAY...ALTHOUGH IT
MAY BE BRINGING IT TOO FAR E (LI FORKS).
ALL THAT SAID...HAVE HIGHEST POPS THIS MORNING AND IN THE WESTERN
THIRD OF THE CWA. WISH THERE WAS MORE CONSISTENCY WITH THE POPS
THIS AFTN AND EVE...BUT HAVE LOW CONFIDENCE IN TIMING...DURATION
AND LOCATION OF PCPN DURING THIS TIME.
HIGHS WILL LIKELY BE A FEW DEGREES WARMER IN EASTERN ZONES WITH
THE EXPECTATION THAT RAIN DOESN`T MAKE IT THAT FAR EAST. HAVE
FORECASTED LOWER 60S ACROSS THE WESTERN HALF OF THE AREA AND MID
TO UPPER 60S EAST...BUT AGAIN WILL ULTIMATELY DEPEND ON WHERE THE
PRECIP COMES TO A HALT.
LOWS TONIGHT ALSO FOLLOW THE AFOREMENTIONED IDEA WITH COOLER TEMPS
EAST WITH CLEARING OCCURRING THERE FIRST AND A FEW DEGREES WARMER
WEST WITH MORE CLOUD COVER.
&&
.SHORT TERM /TUESDAY/...
KEPT A FEW HOURS OF SCHC POPS ACROSS W ZONES TUE MORNING FOR ANY
STRAY AREAS OF RAIN THAT MAY REMAIN. OTHERWISE...RIDGING BUILDS
BACK TO THE W WITH DRY WEATHER AND CLEARING SKIES. WESTERN AREAS
MAY NOT SEE A WHOLE LOT OF SUNSHINE DURING THE DAY WITH THE
DISTURBANCE TO THE SW...HOWEVER STILL EXPECT SLIGHTLY WARMER MAX
TEMPS THAN ON MONDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
CONDITIONS CONTINUE TO LOOK MOSTLY DRY AND QUIET WEDNESDAY THROUGH
THE COMING WEEKEND WITH SURFACE HIGH PRESSURE SITTING OVER THE
NORTHEAST AND UPPER LEVEL RIDGING BUILDING ALOFT.
AS THE RIDGE BUILDS TUES NIGHT INTO WED...A WEAK SHORTWAVE WITH THE
ASSOCIATED VORT MAX LOOKS TO PASS OVER THE FAR WESTERN REGIONS OF
THE CWA. THIS COULD TRIGGER VERY LIGHT PCPN OVER PORTIONS OF NJ
THROUGH THE NIGHT TUES...THOUGH WITH BUFKIT SOUNDINGS INDICATING A
FAIRLY DRY VERTICAL PROFILE...PSBL THAT NO PCPN ACTUALLY OCCURS.
WILL KEEP ONLY LOW END SLIGHT CHC POPS.
THE RIDGE BUILDS AND TAKES HOLD OF THE REGION BY THURS. SOME MODEL
DIFFERENCES ON THE EXTENT OF THE RIDGE AND PLACEMENT...WITH THE 00Z
NAM AND ECMWF BOTH KEEPING THE RIDGE SLIGHTLY FARTHER WEST...AND
THUS ALLOWING MULTIPLE SHORTWAVES TO PASS WITHIN THE VICINITY OF THE
AREA. HOWEVER...WITH LOW CONFIDENCE OF THE SETUP...WILL CONTINUE A
DRY FORECAST THROUGH THE WEEKEND.
THE NEXT CONCERN WILL BE A DEVELOPING CLOSED LOW ALOFT...WITH THE
MODELS NOW SEEMING TO TREND TO A SLIGHTLY SLOWER SOLUTION...KEEPING
IT OVER THE CENTRAL US THROUGH THE WEEKEND. DID BRING IN SLIGHT CHC
POPS AGAIN FOR THE END OF THE FORECAST...THE BEGINNING OF NEXT
WEEK...TO ACCOUNT FOR THE RIDGING PUSHING OFF TO THE EAST...AND
MULTIPLE MORE SHORTWAVES PASSING THROUGH THE REGION.
LITTLE TEMPERATURE VARIATIONS THROUGH THE PERIOD...WITH HIGHS
GENERALLY IN THE 60S TO LOWER 70S...AND OVERNIGHT LOWS IN THE 40S.
ONSHORE FLOW WILL KEEP COASTAL REGIONS COOLER...WITH THE HIGHER
TEMPS OVER INTERIOR NY...AND CT. USED A BLEND OF WPC/MOS FOR TEMPS
AND DEW PTS.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL REMAIN ANCHORED FROM THE CANADIAN MARITIMES
THROUGH THE GULF OF MAINE OVER THE NEXT SEVERAL DAYS.
PERIODS OF LIGHT RAIN WILL IMPACT WRN TERMINALS TODAY. THIS
ACTIVITY HOWEVER LOOKS TO REMAIN VFR. THERE IS A LOW POTENTIAL FOR
A FEW POCKETS OF MVFR THIS AFTN.
ONE OF THE MODELS DOES PROG MORE RAIN AND MVFR/IFR POTENTIAL FOR
TNGT. THIS IS THE RESULT OF CONVECTIVE ENHANCEMENT OF SHRA S OF OUR
AREA TODAY. ALTHOUGH THIS SCENARIO IS A LOW PROBABILITY...THERE IS
A SMALL CHC THAT SIGNIFICANT CHANGES TO THE TAFS ARE POSSIBLE FOR
TNGT.
S FLOW WILL BACK TO THE SE BY 14Z. THE SE FLOW WILL THEN REMAIN IN
PLACE THRU MOST OF TNGT. WIND SPEEDS INCREASE TO 10-15KT BY
18Z...THEN DECREASE AGAIN AFT 00Z.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.
.OUTLOOK FOR 06Z TUE THROUGH FRI...
.MON NGT...MAINLY VFR. MVFR OR LOWER POSSIBLE IS RAIN IS MORE
EXTENSIVE THAT EXPECTED ATTM.
.TUE-FRI...MAINLY VFR. MVFR OR LOWER CONDS POSSIBLE EACH NIGHT AND
MORNING.
&&
.MARINE...
SUB-ADVSY CONDS ARE EXPECTED ON THE WATERS THROUGH TUE WITH SELY
WINDS BACKING TO THE E AS RETREATING HIGH PRES BUILDS BACK DOWN
FROM THE NE TONIGHT AND TUE. WINDS INCREASE A BIT TONIGHT WITH A
TIGHTENING PRES GRADIENT AND GUSTS MAY APPROACH SCA LEVELS
TONIGHT IF THERE IS SOME MIXING...BUT WOULD ONLY EXPECT OCNL
GUSTS UP TO 25 KT AT BEST. ELY SWELL ALSO CONTINUES AND ALTHOUGH
WINDS WILL BE RELATIVELY LIGHT...EXPECT THE COMBINATION OF WIND
WAVES AND SWELL TO INCREASE SEAS TO AROUND 4 FT ON THE OCEAN
WATERS TUE MORNING.
GENERALLY SUB-SCA CONDITIONS ON ALL WATERS
MID WEEK THROUGH THE BEGINNING OF NEXT WEEK. A PERSISTENT EASTERLY
FLOW COULD BUILD THE OCEAN SEAS UP TO 5 FT FOR A PERIOD WED NIGHT
INTO THURS. SEAS COULD REACH 5 FT AGAIN OVER THE COMING WEEKEND
WITH INCREASED NELY FLOW FROM THE INTERACTION BETWEEN THE SITTING
HIGH...AND LOW PRESSURE TO THE SOUTH.
&&
.HYDROLOGY...
A THIRD OF AN INCH OF RAINFALL IS POSSIBLE ON AVERAGE ACROSS NYC
AND POINTS WEST MON/MON NIGHT...WITH LESSER AMOUNTS TO THE EAST.
NO SIGNIFICANT PRECIPITATION IS EXPECTED TUESDAY THROUGH SUNDAY.
&&
.EQUIPMENT...
RIVERHEAD NY NOAA ALL HAZARDS RADIO TRANSMITTER IS OUT OF SERVICE.
RETURN TO SERVICE TIME UNKNOWN ATTM.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
130 AM EDT MON APR 29 2013
.SYNOPSIS...
HIGH PRESSURE HAS RETREATED TO THE EAST. AN BAND OF SHOWERS WAS
ATTEMPTING TO MOVE INTO AREAS WEST OF THE HUDSON. SCATTERED SHOWERS
WILL WORK INTO MOST AREAS ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 PM EDT...WENT AHEAD AND RAISED OVERNIGHT LOW TEMPERATURES
A FULL CATEGORY (3 DEGREES) ACROSS THE BOARD. CLOUDS WERE IN TO
STAY...AND MOST AREAS NOW HAD A BREEZE 5 TO 10 MPH FROM THE
SOUTH...AND IN SOME CASES GUSTING TO OVER 20 MPH. THESE TWO FACTORS
(CLOUDS AND BREEZE) WILL KEEP TEMPERATURES FROM FALLING A WHOLE LOT
MORE OVERNIGHT.
WATCHING A BAND OF SHOWERS NEAR I-81 BUT AS THEY MOVE INTO DRY AIR
HAVE HAD A HARD TIME MOVING EAST. THE EXPERIMENTAL HRRR EARLIER
INDICATED SHOWERS WOULD MOVE INTO THE CAPITAL DISTRICT BY SUNRISE.
HOWEVER...THE LATEST VERSION HAS BACKED OFF THIS ARRIVAL TIME UNTIL
AFTER SUNRISE...WHICH GENERALLY AGREED WITH THE 00Z AND INCOMING 00Z
GFS. FOR NOW...MADE NO CHANGES IN THE POP FIELDS.
SO FOR THE REST OF OVERNIGHT...IT WILL STAY RELATIVELY MILD WITH
LOWS AROUND 50 IN THE GREATER CAPITAL DISTRICT....MID OR UPPER 40S
MOST OTHER PLACES. THE SOUTH BREEZE WILL CONTINUE AND LIGHT
SCATTERED SHOWERS WILL SLOWLY WORK TO THE WEST OF THE HUDSON
BRINGING UNDER A TENTH OF AN INCH OF RAINFALL. IT SHOULD REMAIN DRY
FROM THE HUDSON VALLEY ON EASTWARD ALTHOUGH CLOUDS WILL THICKEN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
SOME QUITE NOTICEABLE DISCREPANCIES IN SOURCES OF GUIDANCE THROUGH
THE PERIOD...ESPECIALLY IN THE TOMORROW NIGHT THROUGH WEDNESDAY
TIME FRAME. UNTIL THEN...THE WEAKENING UPPER DISTURBANCE IS
EXPECTED TO WASH OUT...WITH THE EASTERN EXTENT OF THE AREA OF
SHOWERS A BIT IN QUESTION. THE BATTLE BETWEEN THE RIDGING OFF
CANADA AND THE ADVANCING MOISTURE IN THE WEAKENING UPPER
DISTURBANCE SHOULD SUPPORT SOME AREA OF SCATTERED SHOWERS ALONG
AND WEST OF THE HUDSON VALLEY...WITH ONLY ISOLATED ACTIVITY EAST
OF THE HUDSON VALLEY INTO WESTERN NEW ENGLAND. SOME PARTS OF
WESTERN NEW ENGLAND MAY NOT SEE ANY RAIN THROUGH WEDNESDAY
DEPENDING ON HOW THE WEAKENING UPPER DISTURBANCE EVOLVES.
SO...ON MONDAY...CLOUDS THICKEN...AND SCATTERED SHOWERS GRADUALLY
BUILD EAST. LIGHT SOUTH TO SOUTHEAST WINDS SHOULD NOT HELP MIXING
MUCH. SO HIGHS MAINLY IN THE 60S. SCATTERED SHOWERS CONTINUE TO
GRADUALLY SPREAD EAST MONDAY NIGHT...BUT HOW FAR EAST IS THE
QUESTION. EVEN AREAS THAT DO NOT SEE SHOWERS SHOULD SEE A MOSTLY
CLOUDY TO CLOUDY SKY. LOWS SHOULD BE IN THE MID TO UPPER
40S...SOME LOWER 40S SOUTHERN ADIRONDACKS.
TUESDAY INTO WEDNESDAY IS PERIOD OF VERY LOW CONFIDENCE. ONE SET
OF GUIDANCE HAS HIGH PRESSURE STRENGTHENING OVER SOUTHEASTERN
CANADA AND EASTERN NEW ENGLAND...PUSHING CLEARING AND DRYING WEST
INTO OUR REGION. OTHER SETS OF GUIDANCE HAVE LINGERING CLOUDS AND
A SLOWER MORE GRADUAL STRENGTHENING OF THE HIGH PRESSURE TO THE
EAST AND MORE GRADUAL BUILDING WEST OF THE DRYER AIRMASS. THE
CURRENT CLOUD AND MOISTURE FIELD ASSOCIATED WITH THE SYSTEM IS
QUITE EXTENSIVE...SO IT WOULD SEEM THAT IT WOULD TAKE QUITE A BIT
OF TIME FOR THE ATMOSPHERE TO MIX OUT ALL THAT MOISTURE AS THE
UPPER DISTURBANCE WEAKENS...EVEN WE EXPERIENCE LESS RAIN AND
MOSTLY MID AND HIGH LEVEL CLOUDINESS.
AT THIS TIME...SIDING WITH THE LINGERING MOISTURE AND CLOUDS AND
THE SLOWER DEVELOPMENT OF THE RIDGING...WHICH WOULD LIMIT THE
SUNSHINE TO SOME DEGREE...AND RESULT IN TEMPERATURES ON THE
COOLER SIDE OF GUIDANCE TUESDAY AND LOW TEMPERATURES ON THE WARMER
SIDE OF GUIDANCE TUESDAY NIGHT. COOLER BOUNDARY LAYER TEMPERATURES
ARE FORECASTED BUILD WEST AS THE RIDGING STRENGTHENS TO THE
EAST...SO EVEN IF WE END UP HAVING MORE CLEARING IN EASTERN NY AND
WESTERN NEW ENGLAND...THE WARMING COULD BE LIMITED DUE TO THE
COOLER BOUNDARY LAYER TEMPERATURES. ALSO...WITH SOUTH TO SOUTHEAST
LOW LEVEL FLOW...THERE COULD BE SOME LINGERING MARINE LAYER TYPE
CLOUDS...BUT AGAIN...TOO FAR OUT TO HAVE HIGH CONFIDENCE. ALL
GUIDANCE SUGGESTS THERE SHOULD BE DECREASING COVERAGE OF SHOWERS
LATER MONDAY NIGHT THROUGH TUESDAY NIGHT...ALSO GETTING CONFINED
MORE WESTWARD WITH TIME AS THE UPPER RIDGING DOES BUILD WEST FROM
NEW ENGLAND AND CANADA.
HIGHS TUESDAY IN THE 60S WITH LOWS TUESDAY NIGHT IN THE 40S...SOME
30S IN THE SOUTHERN ADIRONDACKS...AND PARTS OF THE SOUTHERN GREEN
MOUNTAINS AND BERKSHIRES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH MOST OF THIS PERIOD.
THIS SHOULD KEEP OUR REGION GENERALLY FAIR...WITH JUST SOME
OCCASIONAL CLOUDINESS...ESP ACROSS SOUTHERN AREAS WHERE SOME
PERIODIC MARINE INFLUENCE/MOISTURE MAY REACH. TEMPERATURES SHOULD
REMAIN ABOVE SEASONAL LEVELS...WITH MAX TEMPS REACHING 70-75 IN
VALLEY AREAS...WARMEST ACROSS THE WESTERN MOHAWK VALLEY AND UPPER
HUDSON VALLEY WHICH WILL HAVE THE LEAST OF ANY POTENTIAL MARINE
INFLUENCE AND COOLING...AND GENERALLY 65-70 ACROSS HIGHER
ELEVATIONS. OVERNIGHT MINS SHOULD FALL INTO THE LOWER 40S WITHIN
MOST VALLEY LOCALES...AND 30S ACROSS HIGHER ELEVATIONS.
THERE IS SOME POSSIBILITY OF A WEAK BACKDOOR COLD FRONT TO SETTLING
SOUTH/WEST ACROSS THE REGION DURING FRIDAY...WHICH THE 12Z/28 ECMWF
HINTS AT BEST. THIS COULD CREATE A BIT MORE CLOUDINESS AT SOME POINT
ON FRIDAY...AND PERHAPS AN ISOLATED SHOWER OR TWO. HOWEVER...AT THIS
TIME RANGE...IT APPEARS TO BE A LOW ENOUGH PROBABILITY TO KEEP OUT
ANY MENTION IN ONGOING FORECAST.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL SETTLE ALONG THE NEW ENGLAND COAST TONIGHT INTO
MONDAY...AS A WEAKENING UPPER LEVEL DISTURBANCE APPROACHES FROM THE
OHIO VALLEY AND MID ATLANTIC REGION. THIS WILL RESULT IN GRADUALLY
INCREASING CLOUDS WITH LOWERING CIGS THROUGH THE PERIOD ENDING AT
06Z TUESDAY. DESPITE THE APPROACH OF THE UPPER LEVEL DISTURBANCE...
EXPECT MAINLY VFR CONDITIONS AT THE KGFL/KALB/KPOU/KPSF TAF SITES
THROUGH 06Z TUESDAY AS MODELS INDICATE LITTLE IF ANY PCPN WILL REACH
THE TAF SITES. WHERE THE THREAT OF ISOALTED TO SCT SHOWERS EXIST...
HAVE INCLUDED VCSH IN THE FORECAST.
WINDS WILL BE SOUTH TO SOUTHEAST AT 10 KT OR LESS THORUGH A FEW
HOURS AFTER SUNRISE AT KGFL/KALB...BUT THERE COULD STILL BE A FEW
GUSTS UP TO AROUND 15 KTS. AT KPSF/KPOU EXPECT LIGHT WINDS DURING
THIS PERIOD. LATER MONDAY MORNING THE SOUTH TO SOUTHEAST WINDS WILL
INCREASE AGAIN TO 8 TO 12 KTS WITH SOME GUSTS TO 15 TO 18 KTS...
ESPECIALLY AT KALB. AFTER SUNSET WITH WINDS WILL BECOME LIGHT ONCE
AGAIN...EXCEPT REMAIN SOUTH AT AROUND 10 KTS AT KALB.
OUTLOOK...
LATE MON NT...MAINLY VFR. CHC -SHRA AND ASSOC MVFR.
TUE-TUE NT...MAINLY VFR. SLIGHT CHC -SHRA AND POSS STRATUS WITH MVFR.
WED-FRI...VFR. NO SIG WX.
&&
.FIRE WEATHER...
SURFACE HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE NORTHEAST
UNTIL IT MOVES EAST OFF NEW ENGLAND TOMORROW. THE NEXT THREAT
OF RAIN IS LATE TOMORROW INTO TUESDAY AS A WEAK UPPER LEVEL
DISTURBANCE TRACKS THROUGH THE REGION.
RH VALUES WILL INCREASE TO THE 75 TO 100 PERCENT RANGE
TONIGHT...THEN DROP TO DROP TO MAINLY THE 35 TO 45 PERCENT RANGE
TOMORROW AFTERNOON. RH VALUES WILL INCREASE TO THE 75 TO 100
PERCENT RANGE TOMORROW NIGHT...THEN DROP TO DROP TO MAINLY THE 35
TO 45 PERCENT RANGE TUESDAY.
WINDS SHOULD BE SOUTH TO SOUTHEAST AT LESS THAN 15 MPH
TONIGHT...THEN INCREASE TO AROUND 15 MPH TOMORROW...DROPPING BELOW
15 MPH AGAIN TOMORROW NIGHT...AND AROUND 15 MPH TUESDAY.
SHOWERS SHOULD ONLY BE SCATTERED TOMORROW THROUGH TUESDAY...WITH
THE BEST COVERAGE WEST OF THE HUDSON VALLEY. RAINFALL AMOUNTS
SHOULD BE LESS THAN A QUARTER INCH THROUGH THE PERIOD.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED IN THE ALY HYDRO SERVICE AREA THE
NEXT 5 DAYS. RAINFALL WITH THE NEXT SYSTEM LATE TOMORROW INTO
TUESDAY...LOOKS TO BE A QUARTER INCH OR LESS WHICH WOULD RESULT
IN NO SIGNIFICANT RISES ON ANY WATERSHEDS.
DRY WEATHER LOOKS TO RETURN LATER TUESDAY INTO MUCH OF THE REMAINDER
OF WEEK.
THE SPOTTY SNOWPACK IN THE SOUTHERN ADIRONDACKS AND SOUTHERN GREENS
IS NOT EXPECTED TO CAUSE ANY HYDRO CONCERNS. OVERALL...FLOWS WILL
CONTINUE TO LOWER IN THE PREDOMINANTLY DRY REGIME THE NEXT SEVERAL
DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV
NEAR TERM...HWJIV/KL
SHORT TERM...NAS
LONG TERM...KL
AVIATION...GJM
FIRE WEATHER...NAS
HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1230 AM EDT MON APR 29 2013
.SYNOPSIS...
HIGH PRESSURE HAS RETREATED TO THE EAST. AN BAND OF SHOWERS WAS
ATTEMPTING TO MOVE INTO AREAS WEST OF THE HUDSON. SCATTERED SHOWERS
WILL WORK INTO MOST AREAS ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1230 PM EDT...WENT AHEAD AND RAISED OVERNIGHT LOW TEMPERATURES
A FULL CATEGORY (3 DEGREES) ACROSS THE BOARD. CLOUDS WERE IN TO
STAY...AND MOST AREAS NOW HAD A BREEZE 5 TO 10 MPH FROM THE
SOUTH...AND IN SOME CASES GUSTING TO OVER 20 MPH. THESE TWO FACTORS
(CLOUDS AND BREEZE) WILL KEEP TEMPERATURES FROM FALLING A WHOLE LOT
MORE OVERNIGHT.
WATCHING A BAND OF SHOWERS NEAR I-81 BUT AS THEY MOVE INTO DRY AIR
HAVE HAD A HARD TIME MOVING EAST. THE EXPERIMENTAL HRRR EARLIER
INDICATED SHOWERS WOULD MOVE INTO THE CAPITAL DISTRICT BY SUNRISE.
HOWEVER...THE LATEST VERSION HAS BACKED OFF THIS ARRIVAL TIME UNTIL
AFTER SUNRISE...WHICH GENERALLY AGREED WITH THE 00Z AND INCOMING 00Z
GFS. FOR NOW...MADE NO CHANGES IN THE POP FIELDS.
SO FOR THE REST OF OVERNIGHT...IT WILL STAY RELATIVELY MILD WITH
LOWS AROUND 50 IN THE GREATER CAPITAL DISTRICT....MID OR UPPER 40S
MOST OTHER PLACES. THE SOUTH BREEZE WILL CONTINUE AND LIGHT
SCATTERED SHOWERS WILL SLOWLY WORK TO THE WEST OF THE HUDSON
BRINGING UNDER A TENTH OF AN INCH OF RAINFALL. IT SHOULD REMAIN DRY
FROM THE HUDSON VALLEY ON EASTWARD ALTHOUGH CLOUDS WILL THICKEN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
SOME QUITE NOTICEABLE DISCREPANCIES IN SOURCES OF GUIDANCE THROUGH
THE PERIOD...ESPECIALLY IN THE TOMORROW NIGHT THROUGH WEDNESDAY
TIME FRAME. UNTIL THEN...THE WEAKENING UPPER DISTURBANCE IS
EXPECTED TO WASH OUT...WITH THE EASTERN EXTENT OF THE AREA OF
SHOWERS A BIT IN QUESTION. THE BATTLE BETWEEN THE RIDGING OFF
CANADA AND THE ADVANCING MOISTURE IN THE WEAKENING UPPER
DISTURBANCE SHOULD SUPPORT SOME AREA OF SCATTERED SHOWERS ALONG
AND WEST OF THE HUDSON VALLEY...WITH ONLY ISOLATED ACTIVITY EAST
OF THE HUDSON VALLEY INTO WESTERN NEW ENGLAND. SOME PARTS OF
WESTERN NEW ENGLAND MAY NOT SEE ANY RAIN THROUGH WEDNESDAY
DEPENDING ON HOW THE WEAKENING UPPER DISTURBANCE EVOLVES.
SO...ON MONDAY...CLOUDS THICKEN...AND SCATTERED SHOWERS GRADUALLY
BUILD EAST. LIGHT SOUTH TO SOUTHEAST WINDS SHOULD NOT HELP MIXING
MUCH. SO HIGHS MAINLY IN THE 60S. SCATTERED SHOWERS CONTINUE TO
GRADUALLY SPREAD EAST MONDAY NIGHT...BUT HOW FAR EAST IS THE
QUESTION. EVEN AREAS THAT DO NOT SEE SHOWERS SHOULD SEE A MOSTLY
CLOUDY TO CLOUDY SKY. LOWS SHOULD BE IN THE MID TO UPPER
40S...SOME LOWER 40S SOUTHERN ADIRONDACKS.
TUESDAY INTO WEDNESDAY IS PERIOD OF VERY LOW CONFIDENCE. ONE SET
OF GUIDANCE HAS HIGH PRESSURE STRENGTHENING OVER SOUTHEASTERN
CANADA AND EASTERN NEW ENGLAND...PUSHING CLEARING AND DRYING WEST
INTO OUR REGION. OTHER SETS OF GUIDANCE HAVE LINGERING CLOUDS AND
A SLOWER MORE GRADUAL STRENGTHENING OF THE HIGH PRESSURE TO THE
EAST AND MORE GRADUAL BUILDING WEST OF THE DRYER AIRMASS. THE
CURRENT CLOUD AND MOISTURE FIELD ASSOCIATED WITH THE SYSTEM IS
QUITE EXTENSIVE...SO IT WOULD SEEM THAT IT WOULD TAKE QUITE A BIT
OF TIME FOR THE ATMOSPHERE TO MIX OUT ALL THAT MOISTURE AS THE
UPPER DISTURBANCE WEAKENS...EVEN WE EXPERIENCE LESS RAIN AND
MOSTLY MID AND HIGH LEVEL CLOUDINESS.
AT THIS TIME...SIDING WITH THE LINGERING MOISTURE AND CLOUDS AND
THE SLOWER DEVELOPMENT OF THE RIDGING...WHICH WOULD LIMIT THE
SUNSHINE TO SOME DEGREE...AND RESULT IN TEMPERATURES ON THE
COOLER SIDE OF GUIDANCE TUESDAY AND LOW TEMPERATURES ON THE WARMER
SIDE OF GUIDANCE TUESDAY NIGHT. COOLER BOUNDARY LAYER TEMPERATURES
ARE FORECASTED BUILD WEST AS THE RIDGING STRENGTHENS TO THE
EAST...SO EVEN IF WE END UP HAVING MORE CLEARING IN EASTERN NY AND
WESTERN NEW ENGLAND...THE WARMING COULD BE LIMITED DUE TO THE
COOLER BOUNDARY LAYER TEMPERATURES. ALSO...WITH SOUTH TO SOUTHEAST
LOW LEVEL FLOW...THERE COULD BE SOME LINGERING MARINE LAYER TYPE
CLOUDS...BUT AGAIN...TOO FAR OUT TO HAVE HIGH CONFIDENCE. ALL
GUIDANCE SUGGESTS THERE SHOULD BE DECREASING COVERAGE OF SHOWERS
LATER MONDAY NIGHT THROUGH TUESDAY NIGHT...ALSO GETTING CONFINED
MORE WESTWARD WITH TIME AS THE UPPER RIDGING DOES BUILD WEST FROM
NEW ENGLAND AND CANADA.
HIGHS TUESDAY IN THE 60S WITH LOWS TUESDAY NIGHT IN THE 40S...SOME
30S IN THE SOUTHERN ADIRONDACKS...AND PARTS OF THE SOUTHERN GREEN
MOUNTAINS AND BERKSHIRES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH MOST OF THIS PERIOD.
THIS SHOULD KEEP OUR REGION GENERALLY FAIR...WITH JUST SOME
OCCASIONAL CLOUDINESS...ESP ACROSS SOUTHERN AREAS WHERE SOME
PERIODIC MARINE INFLUENCE/MOISTURE MAY REACH. TEMPERATURES SHOULD
REMAIN ABOVE SEASONAL LEVELS...WITH MAX TEMPS REACHING 70-75 IN
VALLEY AREAS...WARMEST ACROSS THE WESTERN MOHAWK VALLEY AND UPPER
HUDSON VALLEY WHICH WILL HAVE THE LEAST OF ANY POTENTIAL MARINE
INFLUENCE AND COOLING...AND GENERALLY 65-70 ACROSS HIGHER
ELEVATIONS. OVERNIGHT MINS SHOULD FALL INTO THE LOWER 40S WITHIN
MOST VALLEY LOCALES...AND 30S ACROSS HIGHER ELEVATIONS.
THERE IS SOME POSSIBILITY OF A WEAK BACKDOOR COLD FRONT TO SETTLING
SOUTH/WEST ACROSS THE REGION DURING FRIDAY...WHICH THE 12Z/28 ECMWF
HINTS AT BEST. THIS COULD CREATE A BIT MORE CLOUDINESS AT SOME POINT
ON FRIDAY...AND PERHAPS AN ISOLATED SHOWER OR TWO. HOWEVER...AT THIS
TIME RANGE...IT APPEARS TO BE A LOW ENOUGH PROBABILITY TO KEEP OUT
ANY MENTION IN ONGOING FORECAST.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL SETTLE ALONG THE NEW ENGLAND COAST TONIGHT INTO
MONDAY...AS A WEAKENING UPPER LEVEL DISTURBANCE APPROACHES FROM THE
OHIO VALLEY AND MID ATLANTIC REGION. THIS WILL RESULT IN GRADUALLY
INCREASING CLOUDS WITH LOWERING CIGS THROUGH THE PERIOD STARTING
THIS EVENING. STILL...CIGS EXPECTED TO REMAIN IN VFR RANGE THROUGH
MOST OF THE 24 HOUR PERIOD ENDING 00Z TUESDAY. WILL INTRODUCE VCSH
AT KPOU AND KALB BETWEEN 08Z-11Z MONDAY ASSOCIATED WITH THE
DISTURBANCE MOVING THROUGH...AND 12Z-14Z AT KGFL AND KPSF...AS
ISOLATED TO SCATTERED...LIGHT RAIN SHOWERS DEVELOP...AND MAY PERSIST
THROUGH MONDAY AFTERNOON.
WINDS WILL BE SOUTH TO SOUTHEAST AT 5-10 KT TONIGHT...AND 8-12 KT BY
MONDAY AFTERNOON. SOME SLIGHTLY STRONGER WINDS WILL BE POSSIBLE AT
KALB DUE TO ENHANCED CHANNELED FLOW WITHIN THE HUDSON RIVER
VALLEY...WITH SOME GUSTS POSSIBLY REACHING AROUND OR OVER 20 KT AT
TIMES TONIGHT THROUGH MONDAY AFTERNOON.
OUTLOOK...
MON NT...MAINLY VFR. CHC -SHRA AND ASSOC MVFR.
TUE-TUE NT...MAINLY VFR. SLIGHT CHC -SHRA AND POSS STRATUS WITH MVFR.
WED-FRI...VFR. NO SIG WX.
&&
.FIRE WEATHER...
SURFACE HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS THE NORTHEAST
UNTIL IT MOVES EAST OFF NEW ENGLAND TOMORROW. THE NEXT THREAT
OF RAIN IS LATE TOMORROW INTO TUESDAY AS A WEAK UPPER LEVEL
DISTURBANCE TRACKS THROUGH THE REGION.
RH VALUES WILL INCREASE TO THE 75 TO 100 PERCENT RANGE
TONIGHT...THEN DROP TO DROP TO MAINLY THE 35 TO 45 PERCENT RANGE
TOMORROW AFTERNOON. RH VALUES WILL INCREASE TO THE 75 TO 100
PERCENT RANGE TOMORROW NIGHT...THEN DROP TO DROP TO MAINLY THE 35
TO 45 PERCENT RANGE TUESDAY.
WINDS SHOULD BE SOUTH TO SOUTHEAST AT LESS THAN 15 MPH
TONIGHT...THEN INCREASE TO AROUND 15 MPH TOMORROW...DROPPING BELOW
15 MPH AGAIN TOMORROW NIGHT...AND AROUND 15 MPH TUESDAY.
SHOWERS SHOULD ONLY BE SCATTERED TOMORROW THROUGH TUESDAY...WITH
THE BEST COVERAGE WEST OF THE HUDSON VALLEY. RAINFALL AMOUNTS
SHOULD BE LESS THAN A QUARTER INCH THROUGH THE PERIOD.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED IN THE ALY HYDRO SERVICE AREA THE
NEXT 5 DAYS. RAINFALL WITH THE NEXT SYSTEM LATE TOMORROW INTO
TUESDAY...LOOKS TO BE A QUARTER INCH OR LESS WHICH WOULD RESULT
IN NO SIGNIFICANT RISES ON ANY WATERSHEDS.
DRY WEATHER LOOKS TO RETURN LATER TUESDAY INTO MUCH OF THE REMAINDER
OF WEEK.
THE SPOTTY SNOWPACK IN THE SOUTHERN ADIRONDACKS AND SOUTHERN GREENS
IS NOT EXPECTED TO CAUSE ANY HYDRO CONCERNS. OVERALL...FLOWS WILL
CONTINUE TO LOWER IN THE PREDOMINANTLY DRY REGIME THE NEXT SEVERAL
DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV
NEAR TERM...HWJIV/KL
SHORT TERM...NAS
LONG TERM...KL
AVIATION...KL/JPV
FIRE WEATHER...NAS
HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
330 AM EDT MON APR 29 2013
.DISCUSSION...
...HIGHER STORM COVERAGE LATER TODAY WITH STRONG STORMS POSSIBLE...
...INCREASINGLY LONG PERIOD SWELL BRINGS HIGH RIP CURRENT THREAT...
CURRENT...AXIS OF MERIDIONAL ATLC HIGH PRESSURE RIDGE LIES ROUGHLY
ALONG 70W...WITH LOW TO MID LEVEL SE-SRLY FLOW IN PLACE OVER THE FL
PENINSULA. WATER VAPOR IMAGERY AND RUC ANLYS FIELDS SHOW POSITIVE
TILT MID-UPPER TROUGH EXTENDING FROM THE CTRL GULF COAST THRU THE
TN VALLEY. JUST AHEAD OF THIS FEATURE THERE APPEARS TO BE A WEAK
VORT INVOF MOBILE BAY. FAIRLY HEALTHY SWATH OF UPPER LEVEL RH AND
DIVG CAN BE SEEN IN THE RUC ANLYS FIELDS TO THE W-NW-N OF FL. SOME
SPOTTY SMALL NWD MOVING SHOWERS NOTED ON LOCAL 88D RADARS STRADDLING
THE PENINSULA OVER BOTH THE GOMEX AND ADJACENT ATLC. SKIES PRETTY
MUCH CLOUD FREE OVER LAND FOR NOW...HOWEVER SOME THICKER CI/CS IS
JUST ABOUT TO MOVE OVHD.
TODAY/TONIGHT...LOCAL AIR MASS WILL TRANSITION TO ONE MUCH MORE
CONDUCIVE FOR PRODUCING PRECIP OVER THE NEXT H12-18 AS DEEPENING
S-SW FLOW DRAWS HIGHER PWAT AIR NORTH AND NEWD ACROSS THE STATE
WHILE INCREASING UPR DIVG WILL AID ASCENT/DEVELOPMENT OF DIURNAL
CONVECTION ALONG/AHEAD OF LOCAL SEA BREEZE BOUNDARIES. THINK MOST
OF THE ACTIVITY WILL TAKE PLACE IN THE 6HR TIME FRAME BETWEEN 4PM
AND 10PM OWING...AS DEEP LAYER MOISTURE WILL HOLD OFF UNTIL AFTER
18Z...WITH PEAK HEATING AND BOUNDARY INTERACTIONS COINCIDING A FEW
HOURS LATER. WENT WITH A 40 POP FOR THIS AFTN ALONG THE SPACE AND
TREASURE COASTS NUDGED POPS UP TO 50 INLAND/VOLUSIA AND 60 AROUND
LAKE OKEECHOBEE OWING TO EXPECTED LAKE ENHANCEMENT TO PRECIP.
KEPT A HEALTHY RAIN CHANCE (50-60) IN FOR MID-LATE AS CONTINUED
FORCED ASCENT COUPLED WITH SUFFICIENTLY DEEP MOISTURE AND NUMEROUS
RESIDUAL OUTFLOW BOUNDARY INTERACTIONS SHOULD KEEP SHOWERS/STORMS
GOING AS THE SWRLY STEERING FLOW CARRIES ACTIVITY BACK TOWARD THE
EAST COAST AND INTO THE ATLC.
PER SWODY1...THERE IS SOME CONCERN FOR SOME STRONG TO MARGINALLY
SEVERE STORMS CENTERED AROUND THE LATE AFTERNOON-SUNSET TIME
FRAME AS TEMPS ALOFT ARE FAIRLY COLD (-12C TO -13C) WHEREAS -10C
IS GENERALLY A RULE OF THUMB VALUE FOR STRONG STORMS. PLAN TO HIT
THE THREATS FOR STRONG WINDS/HAIL IN THE HWO/G-HWO SUITE.
TUE-WED...THE SOUTHERN END OF THE SHORTWAVE MOVING INTO THE EASTERN
US EARLY THIS WEEK WILL CONTINUE ACROSS THE SOUTHEAST TUES AND WED
BEFORE BEING ABSORBED IN THE DEEP TROUGH OVER THE ATLANTIC. THE
ASSOCIATED SURFACE FRONT AND WEAK LOW WILL RUN INTO THE LARGE AREA
OF HIGH PRESSURE JUST OFFSHORE THE EASTERN US AND STALL
OUT...LEAVING WEAK TROUGH ACROSS THE FL PENINSULA THROUGH THE
PERIOD.
THE SMALL DIFFERENCES THAT REMAIN BETWEEN GFS AND ECMWF WITH THE
PLACEMENT OF THE TROUGH/SFC LOW WILL AFFECT WHERE THE HIGHEST RAIN
CHANCES END UP FOR BOTH DAYS. HOWEVER...WITH PLENTIFUL DEEP
MOISTURE...500 MB TEMPS REMAINING AROUND -12C TO -14C...AND THE
SOUTHERN BRANCH OF THE JET STREAM OVER THE SRN GOMEX/GREATER
ANTILLES AT 80-90KTS...EXPECT RAIN CHANCES EVERYWHERE TO REMAIN WELL
ABOVE CLIMO FOR THIS TIME OF YEAR AT 40-60 PERCENT. TUES LOOKS TO BE
THE WETTER OF THE TWO DAYS WITH STEERING FLOW OUT OF THE
WEST...GAINING MORE OF AN EASTERLY COMPONENT ON WED.
MAX TEMPS NEAR AVERAGE...LOW-MID 80S ALONG THE COAST...MID 80S
INLAND. MIN TEMPS SLIGHTLY ABOVE AVERAGE IN THE MID TO UPPER 60S.
THU-SUN...BOTH MODELS SHOW AN OMEGA BLOCK EVOLVING ACROSS THE
CENTRAL-EASTERN US AND WESTERN ATLANTIC BY LATE WEEK...THE
DISAGREEMENT OF COURSE REMAINS IN THE DETAILS.
THE NE SURFACE HIGH WILL EXPAND SOUTHWARDS ON THURSDAY BRINGING THE
WEAK LOW FROM THE EARLIER FRONT BACK INTO THE FL PENINSULA WHERE IT
WILL MEANDER IN THE VICINITY INTO THE WEEKEND. THE ECMWF KEEPS
SIGNIFICANTLY MORE MOISTURE ACROSS THE REGION THROUGH THE
PERIOD...ALONG WITH A SLIGHTLY DEEPER SURFACE LOW UNDER LOWER UPPER
HEIGHTS. THE RESULT IS A MUCH WETTER FRI-SUN WHERE THE GFS HAS POPS
AT 20-30 PERCENT.
HAVE KEPT THE ONGOING FORECAST AT 30-40 PERCENT RATHER THAN GOING
QUITE AS HIGH AS THE ECMWF AS THE FINAL SOLUTION WILL ULTIMATELY
DEPEND ON WHERE THE TROUGH/SFC LOW SETS UP IN RELATION TO THE COAST.
WITH BRISK ONSHORE FLOW DEVELOPING...THERE WILL BE A POSSIBILITY FOR
A FEW HEAVY COASTAL CONVERGENCE BANDS TO SET UP.
&&
.AVIATION...VFR. WITH ISOLD/TS SHRA POSSIBLE ALONG THE VRB-SUA
CORRIDOR STARTING 18Z...THEN INCREASING COVERAGE/THREAT FOR IFR
CIGS/VSBY IN TS RA/+RA AT ALL SITES FROM 20Z-04Z.
&&
.MARINE...SOLID 4-6FT LONG PERIOD 14-15S SWELL WILL REMAIN IN PLACE
TODAY/TONIGHT. WILL KEEP CAUTIONARY STATEMENT IN PLACE...PRIMARILY
FOR HIGHER SEAS AS WINDS SHOULD BE RIGHT AROUND 15KT. AM STRONGLY
CONTEMPLATING GOING WITH CFW FOR HIGH RIP CURRENT RISK AS LOCAL
CHECKLIST YIELDED VALUES IN THE "VERY HIGH" RANGE...EVEN WITH SE
FLOW CREATING A NWD FLOWING LONGSHORE CURRENT...THE ENERGY CREATED
BY THESE VERY LNG PERIOD WAVES ARE SURE TO CUT NUMEROUS...FREQUENT
CHANNELS/BREACHES IN THE SAND BAR UP AND DOWN THE COAST.
TUE-FRI...SURFACE TROUGH WILL MOVE INTO THE CENTRAL PENINSULA ON
TUES WITH SOUTH-SOUTHWEST WINDS EARLY IN THE DAY BECOMING LIGHT AND
VARIABLE BY THE AFTERNOON THROUGH DAYBREAK WED. HIGH PRESSURE WILL
NOSE DOWN THE E COAST IN ITS WAKE WITH STEADY NE FLOW AROUND 10KTS
THROUGH THURSDAY. THE WINDS LATE IN THE WEEK INTO THE WEEKEND WILL
ULTIMATELY DEPEND ON WHERE THE TROUGH AND A WEAK SURFACE LOW SET
UP...BUT MODELS POINT TO A PERIOD OF MODERATE EAST-NORTHEAST FLOW OF
AT LEAST 10-15KTS.
LONG PERIOD SWELL WILL CONTINUE INTO TUES WITH SEAS 4-6FT AT
13-14SEC...SUBSIDING TO 3-5FT WED NIGHT INTO THU...THEN REBUILDING
TO 5-8FT FRI AS THE GRADIENT INCREASES BETWEEN THE TROUGH AND HIGH
TO THE NORTH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 83 65 82 65 / 50 60 60 30
MCO 86 65 86 65 / 40 50 60 20
MLB 83 69 83 68 / 40 60 60 30
VRB 83 69 85 66 / 40 60 60 30
LEE 85 65 85 66 / 50 50 50 20
SFB 87 66 87 67 / 50 50 60 20
ORL 86 66 87 68 / 50 50 60 20
FPR 83 69 85 66 / 40 60 60 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...CRISTALDI
LONG TERM/IMPACT WX....MOSES
AREA FORECAST DISCUSSION...CORRECTED
NWS WAKEFIELD VA
412 AM EDT MON APR 29 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST ACROSS THE MID ATLANTIC TODAY AND OFF
THE COAST TONIGHT. LOW PRESSURE LINGERS OFF THE CAROLINA COAST
THROUGH MIDWEEK AS HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT WATER VAPOR IMAGERY INDICATES A MOIST FRONTAL BAND EXTENDING
FROM THE NORTHERN GULF COAST THROUGH THE MID ATLANTIC AHEAD OF A
MID-LEVEL TROUGH OVER THE OHIO VALLEY. VIGOROUS VERTICAL ASCENT...IN
THE RRQ OF AN 85KT JET CORE OVER THE SUSQUEHANNA VALLEY OF PA (PER
29/06Z RUC) HAS RESULTED IN WIDESPREAD RAIN FROM FROM SC TO NJ AS OF
0730Z. THE LATEST RUC MAINTAINS THIS STRONG LIFT OVER THE LOCAL AREA
THROUGH 12Z BEFORE SHIFTING IT TOWARD THE EASTERN PORTION OF THE
AREA FROM 12-16Z AS THE JET CORE PULLS NE TOWARD LONG ISLAND AND THE
MID-LEVEL TROUGH AXIS INTRUDES FROM THE WEST. THIS SHOULD ALLOW
STEADY RAIN TO SLOWLY TAPER OFF W OF I-95 THROUGH THE MORNING. THE
MAIN AREA OF ASCENT THEN SHIFTS TO SE PORTIONS BY AFTERNOON AS A
SECONDARY SPEED MAX MOVES OVER CENTRAL VA. A FEW RUMBLES OF THUNDER
ARE POSSIBLE OVER SE PORTIONS GIVEN THAT THIS FEATURE ARRIVES DURING
THE AFTERNOON. HOWEVER...AMBIENT RAIN COOLED STABLE CONDITIONS WILL
LIMIT INSTABILITY (AND LIMIT THE POTENTIAL OF DEEP CONVECTION) HENCE
THUNDER WILL NOT BE INCLUDED IN THE GRIDS. THE LATEST DATA SUGGESTS
THAT QPF COULD REACH 1.5IN AND POSSIBLY CLOSE TO 2.0IN FOR SOME
LOCATIONS BY THIS AFTERNOON ACROSS S-CENTRAL/SE VA/EASTERN SHORE/NE
NC. THIS HAS FURTHER SUPPORT FROM UPSTREAM OBS OVER CENTRAL NC WHERE
AMOUNTS HAVE REACHED 1.0-1.5IN AND RAIN CONTINUES.
THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST TONIGHT WITH THE
ASSOCIATED WIND FLOW BECOMING NW (ALBEIT WEAK). THIS SHOULD ALLOW
STEADY RAIN TO TAPER OFF TO SHOWERS THIS EVENING FOR EASTERN AREAS.
THERE IS AN ABUNDANT AMOUNT OF LINGERING LOW-LEVEL MOISTURE THAT
WILL NOT BE SCOURED OUT BY WEAK FLOW...SO WIDESPREAD STRATUS IS
EXPECTED TO DEVELOP. THIS COULD EVENTUALLY SETTLE TO THE SURFACE
RESULTING IN THE POTENTIAL FOR FOG.
CLOUD COVER AND RAIN WILL LIMIT HIGH TEMPERATURES TODAY...WITH
READINGS RANGING FROM THE LOW/MID 60S (UPPER 50S ALONG THE ATLANTIC
COAST) OVER THE EASTERN SHORE TO THE UPPER 60S/NEAR 70 S. LOWS
TONIGHT WILL BE MILD AND LARGELY BE IN THE MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
HIGH PRESSURE RE-EXERTS ITSELF OVER THE CANADIAN MARITIMES TUESDAY
AND WEDNESDAY AND NUDGES SW ALONG THE NEW ENGLAND COAST.
MEANWHILE...A COASTAL TROUGH LINGERS OFF THE CAROLINA COAST. THIS
WILL MAINTAIN ONSHORE FLOW AND PERSISTENT MOSTLY CLOUDY TO OVERCAST
CONDITIONS. THE LATEST GFS/NAM/ECMWF DRAW MOISTURE AROUND THE
NORTHERN PERIPHERY OF THE TROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
AHEAD OF A BACKDOOR FRONT. HOWEVER...CONFIDENCE IS LOW REGARDING
RAIN POTENTIAL AT THIS TIME...SO WILL GO WITH NO HIGHER THAN A 40
POP. THUNDER POTENTIAL SHOULD REMAIN VERY LIMITED DUE TO ONSHORE
FLOW AND SSTS IN THE LOW/MID 50S. IF ANY THUNDER WERE TO OCCUR
(MAINLY TUE) IT WOULD BE OVER INTERIOR NE NC AND S-CENTRAL VA.
AS FOR TEMPERATURES...THE COOLER MAV GUIDANCE HAS BEEN FOLLOWED AS
MET NUMBERS APPEAR TOO WARM BASED ON EXPECTED CLOUD COVER. THIS
RESULTS IN HIGHS TUESDAY RANGING FROM THE LOW/MID 60S OVER THE
EASTERN SHORE...TO THE LOW 70S ALONG AND S OF THE VA/NC BORDER (AWAY
FROM THE COASTS). HIGHS WEDNESDAY SHOULD BE A FEW DEGREES COOLER
RANGING FROM THE LOW 60S OVER THE EASTERN SHORE (PERHAPS UPPER 50S
ALONG THE COAST) THE THE UPPER 60S S. LOW TEMPERATURES SHOULD REMAIN
IN THE 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
STEADIER PCPN HAS BEGUN TO MOVE INTO THE LOCAL AREA EARLY THIS
MORNING WITH MVFR CONDITIONS STARTING TO SHOW UP AT THE TAF SITES.
IFR CONDITIONS ARE EXPECTED TO ARRIVE AROUND DAYBREAK AT KRIC AND
AT ALL OTHER TAF SITES BETWEEN 12-14Z THIS MORNING. IFR CONDITIONS
ARE THEN EXPECTED TO LINGER THE REMAINDER OF THE DAY AS LOW
PRESSURE CONTINUES TO BRING RAIN TO THE AREA. PCPN TRIES TO SLOWLY
TAPER OFF FROM WEST TO EAST TONIGHT BUT MAY NEVER TOTALLY END AT
THE COASTAL SITES. NEVERTHELESS...IFR CIGS EXPECTED TO CONTINUE
INTO TONIGHT. THERE CAN ALSO BE SOME BRIEF IFR CONDITIONS EARLY
THIS MORNING IN BOUTS OF STEADIER RAIN.
OUTLOOK...CONDITIONS IMPROVE ON TUESDAY BUT CHANCES OF RAIN WILL
CONTINUE INTO WEDNESDAY.
&&
.MARINE...
LOW PRESSURE APPROACHES THE AREA FROM THE WEST TODAY...THEN WEAKENS
AS IT CROSSES THE WATERS TONIGHT. LIGHT SE FLOW OVER THE WATERS
EARLY THIS MORNING WILL INCREASE DURING THE DAY TODAY DUE TO AN
INCREASING PRESSURE GRADIENT...ALLOWING FOR WINDS OF 15-20 KNOTS
OVER THE WATERS WITH SOME GUSTS UP TO 25 KT ON THE OCEAN. THE
EASTERLY COMPONENT TO THE WINDS WILL ALLOW SEAS TO BUILD ON THE
OCEAN...REACHING 5-6 BY LATE MORNING. SCA`S REMAIN IN PLACE FOR ALL
THE COASTAL WATERS (MAINLY FOR SEAS) TODAY THRU TUESDAY NIGHT. SCA`S
FOR THE CHES BAY/CURRITUCK SOUND CONTINUE THRU 7 PM THIS EVENING
WHEN THE PRESSURE GRADIENT SHOULD RELAX AND WINDS SUBSIDE. SFC HIGH
PRESSURE REMAINS LOCKED IN PLACE OVER NEW ENGLAND THRU THE COMING
WEEK ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS.
ALTHOUGH WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS
WILL REMAIN AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE
WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>634.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT WEDNESDAY FOR ANZ650-652-
654-656-658.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/LSA
MARINE...JDM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
411 AM EDT MON APR 29 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST ACROSS THE MID ATLANTIC TODAY AND OFF
THE COAST TONIGHT. LOW PRESSURE LINGERS OFF THE CAROLINA COAST
THROUGH MIDWEEK AS HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT WATER VAPOR IMAGERY INDICATES A MOIST FRONTAL BAND EXTENDING
FROM THE NORTHERN GULF COAST THROUGH THE MID ATLANTIC AHEAD OF A
MID-LEVEL TROUGH OVER THE OHIO VALLEY. VIGOROUS VERTICAL ASCENT...IN
THE RRQ OF AN 85KT JET CORE OVER THE SUSQUEHANNA VALLEY OF PA (PER
29/06Z RUC) HAS RESULTED IN WIDESPREAD RAIN FROM FROM SC TO NJ AS OF
0730Z. THE LATEST RUC MAINTAINS THIS STRONG LIFT OVER THE LOCAL AREA
THROUGH 12Z BEFORE SHIFTING IT TOWARD THE EASTERN PORTION OF THE
AREA FROM 12-16Z AS THE JET CORE PULLS NE TOWARD LONG ISLAND AND THE
MID-LEVEL TROUGH AXIS INTRUDES FROM THE WEST. THIS SHOULD ALLOW
STEADY RAIN TO SLOWLY TAPER OFF W OF I-95 THROUGH THE MORNING. THE
MAIN AREA OF ASCENT THEN SHIFTS TO SE PORTIONS BY AFTERNOON AS A
SECONDARY SPEED MAX MOVES OVER CENTRAL VA. A FEW RUMBLES OF THUNDER
ARE POSSIBLE OVER SE PORTIONS GIVEN THAT THIS FEATURE ARRIVES DURING
THE AFTERNOON. HOWEVER...AMBIENT RAIN COOLED STABLE CONDITIONS WILL
LIMIT INSTABILITY (AND LIMIT THE POTENTIAL OF DEEP CONVECTION) HENCE
THUNDER WILL NOT BE INCLUDED IN THE GRIDS. THE LATEST DATA SUGGESTS
THAT QPF COULD REACH 1.5IN AND POSSIBLE CLOSE TO 2.0IN FOR SOME
LOCATIONS BY THIS AFTERNOON ACROSS S-CENTRAL/SE VA/EASTERN SHORE/NE
NC. THIS HAS FURTHER SUPPORT FROM UPSTREAM OBS OVER CENTRAL NC WHERE
AMOUNTS HAVE REACHED 1.0-1.5IN AND RAIN CONTINUES.
THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST TONIGHT WITH THE
ASSOCIATED WIND FLOW BECOMING NW (ALBEIT WEAK). THIS SHOULD ALLOW
STEADY RAIN TO TAPER OFF TO SHOWERS THIS EVENING FOR EASTERN AREAS.
THERE IS AN ABUNDANT AMOUNT OF LINGERING LOW-LEVEL MOISTURE THAT
WILL NOT BE SCOURED OUT BY WEAK FLOW...SO WIDESPREAD STRATUS IS
EXPECTED TO DEVELOP. THIS COULD EVENTUALLY SETTLE TO THE SURFACE
RESULTING IN THE POTENTIAL FOR FOG.
CLOUD COVER AND RAIN WILL LIMIT HIGH TEMPERATURES TODAY...WITH
READINGS RANGING FROM THE LOW/MID 60S (UPPER 50S ALONG THE ATLANTIC
COAST) OVER THE EASTERN SHORE TO THE UPPER 60S/NEAR 70 S. LOWS
TONIGHT WILL BE MILD AND LARGELY BE IN THE MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
HIGH PRESSURE RE-EXERTS ITSELF OVER THE CANADIAN MARITIMES TUESDAY
AND WEDNESDAY AND NUDGES SW ALONG THE NEW ENGLAND COAST.
MEANWHILE...A COASTAL TROUGH LINGERS OFF THE CAROLINA COAST. THIS
WILL MAINTAIN ONSHORE FLOW AND PERSISTENT MOSTLY CLOUDY TO OVERCAST
CONDITIONS. THE LATEST GFS/NAM/ECMWF DRAW MOISTURE AROUND THE
NORTHERN PERIPHERY OF THE TROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
AHEAD OF A BACKDOOR FRONT. HOWEVER...CONFIDENCE IS LOW REGARDING
RAIN POTENTIAL AT THIS TIME...SO WILL GO WITH NO HIGHER THAN A 40
POP. THUNDER POTENTIAL SHOULD REMAIN VERY LIMITED DUE TO ONSHORE
FLOW AND SSTS IN THE LOW/MID 50S. IF ANY THUNDER WERE TO OCCUR
(MAINLY TUE) IT WOULD BE OVER INTERIOR NE NC AND S-CENTRAL VA.
AS FOR TEMPERATURES...THE COOLER MAV GUIDANCE HAS BEEN FOLLOWED AS
MET NUMBERS APPEAR TOO WARM BASED ON EXPECTED CLOUD COVER. THIS
RESULTS IN HIGHS TUESDAY RANGING FROM THE LOW/MID 60S OVER THE
EASTERN SHORE...TO THE LOW 70S ALONG AND S OF THE VA/NC BORDER (AWAY
FROM THE COASTS). HIGHS WEDNESDAY SHOULD BE A FEW DEGREES COOLER
RANGING FROM THE LOW 60S OVER THE EASTERN SHORE (PERHAPS UPPER 50S
ALONG THE COAST) THE THE UPPER 60S S. LOW TEMPERATURES SHOULD REMAIN
IN THE 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
STEADIER PCPN HAS BEGUN TO MOVE INTO THE LOCAL AREA EARLY THIS
MORNING WITH MVFR CONDITIONS STARTING TO SHOW UP AT THE TAF SITES.
IFR CONDITIONS ARE EXPECTED TO ARRIVE AROUND DAYBREAK AT KRIC AND
AT ALL OTHER TAF SITES BETWEEN 12-14Z THIS MORNING. IFR CONDITIONS
ARE THEN EXPECTED TO LINGER THE REMAINDER OF THE DAY AS LOW
PRESSURE CONTINUES TO BRING RAIN TO THE AREA. PCPN TRIES TO SLOWLY
TAPER OFF FROM WEST TO EAST TONIGHT BUT MAY NEVER TOTALLY END AT
THE COASTAL SITES. NEVERTHELESS...IFR CIGS EXPECTED TO CONTINUE
INTO TONIGHT. THERE CAN ALSO BE SOME BRIEF IFR CONDITIONS EARLY
THIS MORNING IN BOUTS OF STEADIER RAIN.
OUTLOOK...CONDITIONS IMPROVE ON TUESDAY BUT CHANCES OF RAIN WILL
CONTINUE INTO WEDNESDAY.
&&
.MARINE...
LOW PRESSURE APPROACHES THE AREA FROM THE WEST TODAY...THEN WEAKENS
AS IT CROSSES THE WATERS TONIGHT. LIGHT SE FLOW OVER THE WATERS
EARLY THIS MORNING WILL INCREASE DURING THE DAY TODAY DUE TO AN
INCREASING PRESSURE GRADIENT...ALLOWING FOR WINDS OF 15-20 KNOTS
OVER THE WATERS WITH SOME GUSTS UP TO 25 KT ON THE OCEAN. THE
EASTERLY COMPONENT TO THE WINDS WILL ALLOW SEAS TO BUILD ON THE
OCEAN...REACHING 5-6 BY LATE MORNING. SCA`S REMAIN IN PLACE FOR ALL
THE COASTAL WATERS (MAINLY FOR SEAS) TODAY THRU TUESDAY NIGHT. SCA`S
FOR THE CHES BAY/CURRITUCK SOUND CONTINUE THRU 7 PM THIS EVENING
WHEN THE PRESSURE GRADIENT SHOULD RELAX AND WINDS SUBSIDE. SFC HIGH
PRESSURE REMAINS LOCKED IN PLACE OVER NEW ENGLAND THRU THE COMING
WEEK ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS.
ALTHOUGH WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS
WILL REMAIN AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE
WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>634.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT WEDNESDAY FOR ANZ650-652-
654-656-658.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/LSA
MARINE...JDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT MON APR 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG 160 KNOT 250-300 MB
JET MOVING INTO THE PAC NW AND A MAINLY ZONAL FLOW DOWNSTREAM TO THE
NRN GREAT LAKES. AT THE SFC...A COLD FRONT EXTENDED FROM LOW PRES
OVER HUDSON BAY TO NEAR JAMES BAY AND THROUGH WRN UPPER MI INTO NW
IA. THE COMBINATION OF LOW LEVEL CONV NEAR THE FRONT AND A WEAK
SHRTWV INTO UPPER SUPPORTED AN AREA OF LIGHT SHOWERS ACROSS CNTRL
UPPER MI INTO ERN LAKE SUPERIOR. HIGH PRES FROM THE NRN PLAINS WAS
BUILDING TOWARD THE REGION BRINGING IN DRIER AIR ALONG WITH CLEARING
SKIES FROM NRN MN INTO WRN LAKE SUPERIOR AND WRN UPPER MI. WITH SOME
LEFTOVER LOW LEVEL MOISTURE FROM THE LIGHT RAIN AND MELTING SNOW
ALONG WITH RADIATIONAL COOLING...SOME FOG HAD DEVELOPED FROM IWD TO
CMX.
RADAR/SATELLITE TRENDS SUGGEST THAT THE AREA OF SHOWERS WILL MOVE
THROUGH THE REST OF THE ERN HALF OF THE CWA THIS MORNING AS THE
FRONT GRADUALLY WEAKENS OVER SRN UPPER MI. AS ANOTHER WEAK SHORTWAVE
OVER SOUTH DAKOTA MOVES TOWARD THE AREA LATE THIS AFTERNOON AND
EVENING...MODELS SUGGEST THAT PCPN WILL AGAIN DEVELOP AND LIFT TO
THE NORTHEAST. HOWEVER...THERE REMAINS SOME UNCERTAINTY WITH THE
TIMING OF THE PCPN DEVELOPMENT AND MOVEMENT AND ON HOW FAR TO THE
NORTH INTO CNTRL UPPER MI THE PCPN WILL EXPAND. SO...ONLY CHANCE
POPS WERE INCLUDED FOR NOW. INSTABILITY TO SUPPORT TSRA...PER MDLS
MUCAPE...IS EXPECTED TO REMAIN SOUTH OF THE AREA.
FARTHER TO THE NORTHWEST...DRY CONDITIONS WILL PREVAIL WITH A
SUNSHINE AND WARM CONDITIONS. WITH 850 MB TEMPS AROUND 8C...TEMPS
SHOULD AGAIN CLIMB INTO THE MID 60S. READINGS IN THE UPPER 50S AND
LOWER 60S AND EXPECTED WHERE GREATER CLOUD COVER PREVAILS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 518 AM EDT MON APR 29 2013
EXTENDED FORECAST BECOMES MORE COMPLEX WITH ADDITION OF
THUNDERSTORMS /SOME ON THE STRONGER SIDE/ TUE AND TUE NIGHT AND SNOW
WED NIGHT INTO FRI. WILL FOCUS ON THESE TWO TIME FRAMES DUE TO MORE
BENIGN WEATHER AT THESE TIMES AND HELPING MANAGE EXTRA WORKLOAD ON
MORE IMPACTFUL HYDROLOGIC ISSUES.
FOR TUE...STARTING 12Z TUE THERE IS WILL BE AN UPPER SHORTWAVE
TROUGH OVER ND...WITH THE ASSOCIATED 995MB SFC LOW OVER NRN MN. THE
SYSTEM WILL MOVE TO HUDSON BAY BY 12Z WED WHILE DRAGGING A COLD
FRONT ACROSS THE CWA. THE COLD FRONT WILL ENCOUNTER VERY WARM LOW
LEVEL TEMPS AS 850MB TEMPS WILL BE AROUND 15C RESULTING IN HIGHS IN
THE 60S AND 70S. THUNDERSTORMS CERTAINLY APPEAR POSSIBLE...WITH EVEN
UP TO AROUND 1000 J/KG OF MUCAPE OVER THE REGION. THANKFULLY...SHEAR
WILL BE WEAK WHICH WILL FURTHER LIMIT SEVERE POTENTIAL. THERE COULD
BE SOME STRONGER STORMS...BUT NO SEVERE WEATHER IS EXPECTED AT THIS
TIME. DO SEE THE FRONT MOVE INTO WRN UPPER MI AROUND 00Z
WED...MOVING TO THE ERN U.P. BY 12Z WED. COULD ALSO SEE SOME HEAVY
RAINFALL...WHICH WILL NOT HELP HYDROLOGIC SITUATION DUE TO SNOWMELT
OVER THE CWA.
AFTER THE SYSTEM MOVES AWAY FROM THE AREA...THE CWA WILL BE SQUEEZED
BETWEEN A DEEPENING UPPER TROUGH JUST W OF THE CWA AND A
STRENGTHENING UPPER RIDGE JUST E OF THE CWA. AN 850MB TROUGH WILL BE
ANCHORED OVER THE CWA. ALL THIS WILL HAPPEN WED AND THU...BEFORE THE
UPPER TROUGH CLOSES OFF OVER MY BY FRI AS THE UPPER RIDGE GETS CUT
OFF AND MOVES INTO THE CWA FROM THE E. FGEN PRECIP ON THE NW SIDE OF
THE 850MB TROUGH WILL LEAD TO THE POSSIBILITY OF SIGNIFICANT PRECIP
OVER THE CENTRAL/WESTERN CWA WED NIGHT INTO FRI...MUCH OF WHICH MAY
BE SNOW OVER THE FARTHER W ZONES. THERE REMAINS A GOOD AMOUNT OF
UNCERTAINTY...BUT HEADLINE WORTHY SNOW DOES LOOK POSSIBLE OVER THE
WRN CWA. WITH AFOREMENTIONED HYDRO CONCERNS...WILL HAVE TO CONTINUE
TO CLOSELY LOOK AT PTYPE/AMOUNTS AS THE WEEK PROGRESSES.
WARMER TEMPS LOOK TO RETURN ON FRI AS 850MB TEMPS INCREASE UP TO
9C...WARMEST E. FOR NEXT WEEKEND...UNCERTAINTY INCREASES
SIGNIFICANTLY...SO WILL JUST USE A CONSENSUS OF MODEL GUIDANCE FOR
THIS PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 132 AM EDT MON APR 29 2013
EXPECT A PERIOD OF MVFR CONDITIONS TO DVLP EARLY THIS MRNG AS
MOISTER LLVL AIR FOLLOWS A BAND OF -SHRA ACRS UPR MI. THE ARRIVAL OF
HI PRES AND DRIER AIR NOW IN THE NRN PLAINS IN THE PRESENCE OF
DAYTIME HEATING LATER THIS MRNG SHOULD BRING AN IMPROVEMENT TO VFR
CONDITIONS AT ALL 3 SITES. MORE CLDS IN ADVANCE OF RETURNING WARM
FNT WL ARRIVE S TO N LATER TODAY. THERE MAY BE SOME -SHRA AND MVFR
CONDITIONS AT SAW BY LATE THIS EVNG CLOSER TO THE RETURNING FNT/MSTR
WITH AN UPSLOPE SE FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT MON APR 29 2013
WINDS SHOULD STAY BELOW 25KT THROUGH THE PERIOD WITH NO GALES
EXPECTED. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&
.HYDROLOGY...
ISSUED AT 518 AM EDT MON APR 29 2013
YESTERDAY SAW TEMPS IN THE 60S AND 70S...FOLLOWED BY LOWS LAST NIGHT
IN THE 40S...WHICH HAS KEPT THE MELTING GOING ACROSS THE CWA. SNOW
DEPTHS HAVE FALLEN 15-20 INCHES IN THE LAST WEEK. THE MOST SNOW
REMAINS ON THE GROUND ACROSS NORTHERN UPPER MICHIGAN IN THE INLAND
AND HIGHER TERRAIN AREAS. STILL HAVE TO MELT ANOTHER 12-20 INCHES OF
SNOW IN SOME OF THESE AREAS. TROUGH MOVING THROUGH TONIGHT INTO
TODAY IS DROPPING GENERALLY AROUND 0.25 INCHES OF RAIN...BUT IN SOME
CASES UP TO .5 INCHES HAS FALLEN. ADDITIONAL RAIN WITH POSSIBLE
THUNDERSTORMS MAY OCCUR TUESDAY INTO TUESDAY NIGHT AS A COLD FRONT
WORKS ACROSS UPPER MICHIGAN. HIGHER MOISTURE OVER THE AREA MAY RESULT
IN HEAVY DOWNPOURS WITH ANY THUNDERSTORMS. MUCH COOLER TEMPERATURES
EXPECTED FOR REST OF WEEK BEHIND THE FRONT. ADDITIONAL CHANCES OF
RAIN AND EVEN SNOW WILL ALSO CONTINUE ACROSS UPPER MICHIGAN FOR THE
REST OF THE WEEK. SO...EVEN THOUGH TEMPERATURES WILL BE COOLER THIS
MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION THAT MAY OCCUR.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...THE ONTONAGON
RIVER AT EWEN AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL REMAIN THE BIGGEST CONFIDENCE
REDUCERS IN RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS
WHERE MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS
YET...ALTHOUGH READINGS WILL BE GATHERED FROM THE PESHEKEE RIVER AND
LAKE MICHIGAMME THIS MORNING BY NWS PERSONNEL WHICH SHOULD HELP GET
A BETTER IDEA OF MELTING CONDITIONS INTO THE BASIN. AT OTHER
LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED TO MORE
ACCURATELY GET A HANDLE OF MELT RATES FOR THE RIVER MODELS. NWS
SURVEY OF THE PESHEKEE RIVER ON SATURDAY REVEALED THICK ICE COVERING
MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4 RIVER GAUGING
LOCATION /AUTOMATED GAUGE DISCONTINUED BUT OBS ARE BEING TAKEN USING
A WIRE WEIGHT GAUGE AT THE LOCATION/ AND THICK ICE COVER ON MOST OF
LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS MAY CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES THROUGH MONDAY. MAIN STEM
RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT OF AREAL
FLOOD PROBLEMS WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. HAVE RECEIVED SOME SPORADIC REPORTS OF AREAL TYPE
FLOODING...BUT NOT ENOUGH SIGNIFICANT REPORTS FOR HAZARD ISSUANCE.
FOR COMPLETE DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE
LATEST RIVER FLOOD WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KC
MARINE...JLB
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
133 AM EDT MON APR 29 2013
.UPDATE...
ISSUED AT 811 PM EDT SUN APR 28 2013
ADDED A SCHC FOR TS OVER THE FAR WRN CWA THIS EVNG TO ACCOUNT FOR
RATHER NARROW LINE OF CONVECTION TAKING SHAPE IN NW WI IN ADVANCE
OF HIER H85 DEWPTS/SSI DOWN TO -1C TO -2C. DRY LLVL AIR WITH INVERTED
V LLVL TEMP/DEWPT PROFILES EVIDENT ON RUC ANALYSIS SDNGS SUG ANY PCPN
WL BE RELATIVELY LGT AND NOT EXACERBATE SN MELT RUNOFF. AS THIS LINE
PRESSES FARTHER TO THE E...EXPECT THE CONVECTION TO WEAKEN WITH ONSET
OF NOCTURNAL COOLING AND AS THE CONVECTION RUNS INTO DRIER ANTECEDENT
AIRMASS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 402 PM EDT SUN APR 28 2013
UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW OVER ILLINOIS WITH
AN ASSOCIATED TROUGH. UPPER FLOW ACROSS THE NORTHERN U.S. IS FAIRLY
ZONAL WITH A MINOR SHORTWAVE OVER EASTERN MT THIS MORNING. THIS
SHORTWAVE MOVES INTO THE AREA TONIGHT AND EXITS THE AREA MON
AFTERNOON. NAM SHOWS SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING
THROUGH ALONG WITH DEEPER MOISTURE TONIGHT INTO MONDAY. GFS AND
ECMWF SHOW ABOUT THE SAME THING.
MOISTURE IS PRETTY LIMITED WITH THIS SYSTEM AND SEE A NARROW BAND OF
PCPN MOVING THROUGH TONIGHT INTO MON WITH THE BAND GETTING HUNG UP
OVER THE EAST LATER IN THE DAY. WITH LIMITED MOISTURE...DO NOT WANT
TO GO MORE THAN LIKELY POPS OR HIGH CHANCE AS THIS BAND SLOWLY MOVES
THROUGH THE AREA. QPF AMOUNTS UP TO 0.30 INCH WITH THIS EVENT SEEM
REASONABLE. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST EXCEPT TO DRY THE WEST OUT A BIT FOR MONDAY AS FRONTAL ZONE
IS ALREADY EAST OF THEM BY AFTERNOON. DID NOT MAKE TOO MANY CHANGES
TO TEMPERATURES EITHER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 402 PM EDT SUN APR 28 2013
AFTER A BRIEF PERIOD OF ZONAL FLOW AND A TASTE OF SPRING...UPPER
HEIGHT PATTERN BECOMES MORE AMPLIFIED BY MID WEEK AS TROUGH DEEPENS
OVER WESTERN CANADA AND RIDGING BUILDS FROM THE LOWER GREAT LAKES
TO EASTERN CANADA. BY LATE WEEK...MODELS INDICATE CUTOFF LOW FORMING
OVER THE CNTRL CONUS. LOW PRESSURE TROUGH MOVES THROUGH EARLY IN THE
WEEK...THEN STALLS OUT JUST TO THE EAST OF UPR GREAT LAKES. BOUNDARY
WILL STAY CLOSE ENOUGH TO UPR MICHIGAN TO RESULT IN CHANCES OF PRECIP
THROUGH THE REST OF THE WEEK.
SFC FRONT ON MONDAY EVENING SHOULD BE JUST TO EAST AND SOUTH OF CWA.
SECONDARY SHORTWAVE MOVING THROUGH IN WSW FLOW ALOFT OUT AHEAD OF
LARGER SCALE TROUGHING TO THE WEST COULD HELP TO DEVELOP MORE
SHOWERS PROBABLY CLOSER TO THE SFC BOUNDARY. HIGHER H85 DWPNTS
LIKELY WILL BE INTERCEPTED BY SFC BOUNDARY OVER NORTHEAST WI TO
ACROSS LK MICHIGAN AND NORTHERN LOWER MICHIGAN. ADVECTION OF THE
MOISTURE THEN LIFTS ACROSS EASTERN HALF OF UPR MICHIGAN THROUGH THE
NIGHT.
LARGER SHORTWAVE/MID-UPPER LEVEL JET STREAK PUSHES ACROSS NORTHERN
PLAINS LATER MONDAY NIGHT AND ACROSS NORTHERN MINNESOTA AND WESTERN
LK SUPERIOR TUESDAY INTO TUESDAY EVENING. MODELS DIFFER ON WHICH
PART OF WAVE IS STRONGER...AND THUS ARE DIFFERENT ON PRIMARY SFC LOW
PLACEMENT. GFS/GEM-NH SHOW A NORTHERN LOW TRACK ALONG MINNESOTA AND
ONTARIO BORDER WHILE ECMWF AND NAM INDICATE DOUBLE BARRELLED LOW
FROM MINNESOTA/ONTARIO AND INTO CENTRAL MINNESOTA. YET...MODELS ALL
SHOW COLD FRONT INTO CNTRL UPR MICHIGAN AROUND 00Z ON WEDNESDAY.
DIFFERNCE MAY IMPACT POTENTIAL FOR CLOUDS AND PRECIP WORKING ACROSS
WESTERN HALF OF UPR MICHIGAN DURING THE FIRST PART OF THE DAY...
WHICH AFFECTS HOW MUCH WARMING WILL BE SEEN AHEAD OF COLD FRONT.
PREFER THE ECMWF/NAM/WPC HAND DRAWN PROG IDEA WITH SECOND SFC LOW
AND POSSIBLE WARM FRONT ACROSS MN/CNTRL WI. SFC-BLYR DWPNTS INTO 50S
WITH THE APPROACHING FRONT ALONG WITH ELEVATED MID-LEVEL LAPSE RATES
SUPPORTS MENTION OF TSRA. BEST CHANCE MID-LATE AFTN WOULD BE OVER
SOUTHWEST AND SOUTH CENTRAL...WITH CHANCES TUESDAY EVENING MOVING
ACROSS REST OF EASTERN HALF OF UPR MICHIGAN FOLLOWING INSTABILITY
AXIS AND STRONGER H85 WINDS. CURRENT POP FORECAST SHOWS EXPECTED
TRENDS WELL. WILL TRIM BACK POPS/QPF OVER THE NORTHWEST CWA ON
TUESDAY EVENING THOUGH IN WAKE OF FRONT AND INSTABILITY AXIS.
APPEARS GREATEST INSTABILITY ON TUESDAY WILL STAY SOUTH OF AREA
CLOSER TO SFC DWPNTS NEAR 60F. SINCE STRONGER WINDS AT H7/H5/H3 ARE
NORTHWEST...REDUCING DEEP LAYER SHEAR...POTENTIAL FOR ANY SVR STORMS
IS LOW OVR CWA. HOWEVER...H85 DWPNTS OVER 10C AND SFC FRONT RUNNING
PARALLEL TO UPPER HEIGHTS COULD RESULT IN HEAVY DOWNPOURS IN THE
CONVECTIVE ELEMENTS. WILL BE SOMETHING TO WATCH AS ANY HEAVIER RAIN
WOULD ONLY AGGREVATE THE ONGOING SNOWMELT AND RISING RIVER LEVELS.
RIDGING ALOFT CONTINUES BUILDING TUESDAY NIGHT INTO WEDNESDAY OVER
THE LOWER GREAT LAKES. UPPER PATTERN WILL CONTINUE TO SLOW. SFC
FRONT THAT MOVES THROUGH ON TUESDAY EVENING MAY NOT EVEN MAKE IT
EAST OF EASTERN UPR OR NORTHERN LOWER MICHIGAN BY 12Z WEDNESDAY. UPR
LAKES WILL BE ON LEADING SIDE OF LARGER TROUGH AND IN AREA OF UPPER
JET DIVERGENCE/H7-H5 JET WEDNESDAY THROUGH THURSDAY. FEASIBLE THAT
ECMWF/GFS IDEA SHOWING PERSISTENT RIBBON OF QPF THROUGH THURSDAY IS
CORRECT WITH THIS LARGE SCALE SETUP AND SINCE UPPER LAKES IS WITHIN
H85 TROUGH/AXIS OF HIGHER H85 DWPNTS NEAR +10C WITH AT LEAST SOME
AREAS OF H85-H7 FRONTOGENESIS. MAIN QUESTION IS EXACTLY WHERE THIS
NARROW RIBBON OF PRECIP WILL SET UP. CONSENSUS OF GFS/ECMWF POINT
TO WESTERN HALF OF UPR MICHIGAN. EXACT LOCATION AND INTENSITY OF THE
PRECIP WILL BE CRITICAL AS IT WILL BE FALLING OVER BASINS THAT
ALREADY SHOULD BE SEEING FLOODING AT THAT TIME. COLDER TEMPS STILL
APPEAR IN THE OFFING JUST IN WAKE OF THE SHARP H85 TROUGH. SINCE
UPPER PATTERN REMAINS AMPLIFIED AND BLOCKED UP WITH SOMEWHAT OF A
OMEGA BLOCK LOOK FROM CNTRL CONUS INTO THE EASTERN ATLANTIC...HAVE
TO GO WITH ECMWF IDEA OF FARTHER WEST POSITION OF H85 TROUGH AND
LESS COLD AIR INTO UPR LAKES. EVEN WITH ECMWF THERMAL FIELDS...
WESTERN AND NORTH CENTRAL PORTIONS OF UPR MICHIGAN WOULD BE ENOUGH
ON THE COLD SIDE TO SEE MAINLY SNOW THURSDAY NIGHT INTO FRIDAY
MORNING. POSSIBLE THAT SOME SNOW ACCUMULATIONS COULD OCCUR OVER
THE HIGHER TERRAIN AREAS.
REST OF THE FORECAST PRETTY UNCERTAIN AS IT WILL ALL DEPEND ON HOW
FAR NORTH CLOSED OFF UPPER LOW MEANDERS NEXT WEEKEND. OVERALL WILL
REMAIN COOL AND UNSETTLED THROUGH THE WEEKEND AND POSSIBLY INTO
EARLY NEXT WEEK AS WELL SINCE THE UPPER LOW ONLY SLOWLY LIFTS OUT OF
THE MIDWEST/GREAT LAKES REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 132 AM EDT MON APR 29 2013
EXPECT A PERIOD OF MVFR CONDITIONS TO DVLP EARLY THIS MRNG AS
MOISTER LLVL AIR FOLLOWS A BAND OF -SHRA ACRS UPR MI. THE ARRIVAL OF
HI PRES AND DRIER AIR NOW IN THE NRN PLAINS IN THE PRESENCE OF
DAYTIME HEATING LATER THIS MRNG SHOULD BRING AN IMPROVEMENT TO VFR
CONDITIONS AT ALL 3 SITES. MORE CLDS IN ADVANCE OF RETURNING WARM
FNT WL ARRIVE S TO N LATER TODAY. THERE MAY BE SOME -SHRA AND MVFR
CONDITIONS AT SAW BY LATE THIS EVNG CLOSER TO THE RETURNING FNT/MSTR
WITH AN UPSLOPE SE FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 PM EDT SUN APR 28 2013
WINDS SHOULD STAY BELOW 25KT THROUGH THE PERIOD WITH NO GALES
EXPECTED. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&
.HYDROLOGY...
ISSUED AT 811 PM EDT SUN APR 28 2013
UPDATE...OPTED TO ISSUE FLOOD ADVY FOR THE CHOCOLAY RIVER AT HARVEY
UNTIL TUE AFTN TO ACCOUNT FOR STEEP RISE OF OBSVD WATER LVL AT THAT
SITE. MOST RECENT OB AT 730 PM SHOWED THE LVL AT 9.38 FT...JUST AN
INCH OR TWO BLO BANKFULL. THE UPDATED RFC FCST SHOWS THIS GAUGE
PEAKING AT 9.8 FT MON AFTN...JUST UNDER THE 10.0 FLOOD STAGE. THIS
LATEST FCST SHOWS THE RIVER FALLING BLO BANKFULL TUE AFTN.
ANOTHER DAY IN THE 60S AND 70S HAS KEPT THE MELTING GOING ACROSS THE
CWA. SNOW DEPTHS HAVE FALLEN 15-20 INCHES IN THE LAST WEEK. THE MOST
SNOW REMAINS ON THE GROUND ACROSS NORTHERN UPPER MICHIGAN IN THE
INLAND AND HIGHER TERRAIN AREAS. STILL HAVE TO MELT ANOTHER 12-20
INCHES OF SNOW IN SOME OF THESE AREAS. TROUGH MOVING THROUGH TONIGHT
INTO MONDAY COULD BRING SHOWERS...BUT RAIN AMOUNTS WILL STAY BLO
0.25 INCH. ADDITIONAL RAIN WITH POSSIBLE TSRA MAY OCCUR TUESDAY AS A
COLD FRONT WORKS ACROSS UPR MICHIGAN. HIGHER MOISTURE OVER THE AREA
MAY RESULT IN HEAVY DOWNPOURS WITH ANY THUNDERSTORMS. MUCH COOLER
TEMPERATURES EXPECTED FOR REST OF WEEK BEHIND THE FRONT. ADDITIONAL
CHANCES OF RAIN AND EVEN SNOW WILL ALSO CONTINUE ACROSS UPR MICHIGAN
FOR THE REST OF THE WEEK. SO...EVEN THOUGH TEMPERATURES WILL BE
COOLER THIS MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION THAT MAY
OCCUR.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...AND EVENTUALLY
THE MICHIGAMME RIVER NEAR REPUBLIC AND WITCH LAKE. MELTING SCENARIOS
STILL REMAIN THE BIGGEST CONFIDENCE REDUCERS IN RIVER FORECASTS AT
THIS POINT...AND IF THE RIVER FORECAST CENTER HAS TO INCREASE THE
MELT FACTOR CORRECTION GOING INTO THE RIVER MODELS THE FORECASTS
WILL LIKELY END UP QUITE A BIT HIGHER. MELT CORRECTION FACTOR
ALREADY WAS INCREASED EARLIER THIS WEEKEND FOR THE MEN RIVER
FORECAST GROUP /RIVERS THAT DRAIN INTO THE MENOMINEE RIVER/...WHICH
HAS KEPT FORECASTS UP TO NEAR RECORD STAGE AT PESHEKEE AND MODERATE
FLOOD STAGE DOWNSTREAM ON THE MICHIGAMME RIVER NEAR REPUBLIC/WITCH
LAKE. WFO SURVEY OF THE PESHEKEE RIVER ON SATURDAY REVEALED THICK
ICE COVERING MOST OF THE RIVER AND THICK ICE COVER ON MOST OF LAKE
MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS MAY CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES THROUGH MONDAY. MAIN STEM
RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT OF AREAL
FLOOD PROBLEMS WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. FOR COMPLETE DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND
THE LATEST RIVER FLOOD WATCHES AND WARNINGS /FFAMQT AND FFWMQT/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...07
LONG TERM...JLA
AVIATION...KC
MARINE...07
HYDROLOGY...KC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
354 AM CDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM CDT MON APR 29 2013
A PACIFIC COLD FRONT...CURRENTLY ENTERING WRN WY...WILL MOVE THROUGH
THE FCST AREA TONIGHT. LOW PRESSURE AHEAD OF THE FRONT WILL DEEPEN
ACROSS WRN SD AND SEND ANOTHER SURGE OF WARM DRY AIR THROUGH THE
FCST AREA. THE RAP WHICH HAS BEEN VERIFYING WELL SUGGESTS 80S FOR
HIGHS TODAY MOST AREAS. DEW POINTS WILL FALL INTO THE 20S ONCE
AGAIN. THE CLEARING AREA ACROSS WY AND SD SHOULD MOVE EAST ACROSS
THE FCST AREA AND PROVIDE SUNNY SKIES TODAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 353 AM CDT MON APR 29 2013
FORECAST CONCERN FOR THE EXTENDED PERIOD REVOLVES AROUND
PRECIPITATION CHANCES MID-WEEK...SOME OF WHICH MAY FALL AS SNOW.
THE UNSETTLED PATTERN REMAINS THROUGH THE ENTIRE FORECAST
PERIOD...AS MODEL CONSENSUS SUGGESTS A STAGNATE PATTERN DEVELOPS
LATE WEEK...WITH A CUTOFF LOW AIMLESSLY MEANDERING THROUGH THE LOWER
MISSOURI VALLEY.
MODELS HAVE COME INTO GOOD AGREEMENT REGARDING THE TIMING OF THE
COLD FRONT...WHICH IS PROGGED TO PASS THROUGH THE FORECAST AREA
EARLY TUESDAY...THUS THE ATMOSPHERE WILL BE CHARACTERIZED BY POST
FRONTAL CONDITIONS...WITH STRONG CAA FILTERING SOUTH ACROSS THE CWA
THROUGH THE DAY ON TUESDAY. HIGHS WILL BE SOME 20-25 DEGREES
FAHRENHEIT COOLER THAN OBSERVED TODAY...WITH MOST READINGS REMAINING
THE 50S. ALSO OF NOTE...SHOWERS WILL BE ON THE INCREASE THROUGH THE
AFTERNOON AS A MID LEVEL SHORTWAVE WORKS IN CONJUNCTION WITH THE
RIGHT REAR ENTRANCE OF A STRONG UPPER JET MAX...PRECIPITATION WILL
SPREAD WEST TO EAST THROUGH THE AFTERNOON...AND SHOULD BECOME
FOCUSED ALONG AN AREA OF MIDLEVEL FRONTOGENETIC FORCING THAT APPEARS
TO BISECT THE CWA FROM SOUTHWEST TO NORTHEAST DURING THE AFTERNOON
HOURS /MAINLY THROUGH THE CENTRAL SANDHILLS/. PRECIPITATION CHANCES
BECOME MORE WIDESPREAD INTO THE EVENING HOURS AND OVERNIGHT AS DPVA
SPREADS EAST FROM ROCKIES ONTO THE NORTHERN HIGH PLAINS. ANALYSIS
OF THE 300-305K ISENTROPIC LAYER INDICATES SEVERAL HOURS /00-06Z
WEDNESDAY/ OF STRONG UPGLIDE TARGETING WESTERN AND NORTH CENTRAL
NEBRASKA...THEREAFTER DOWNGLIDE STARTS TO TAKE CONTROL WITH
CONDENSATION PRESSURE DEFICITS RAPIDLY RISING ABOVE 10MB...THUS CUT
BACK QPF AMOUNTS SOME ON WEDNESDAY WITH MOST LOCATIONS EXPECTING
LESS THAN A HALF OF AN INCH TOTAL QPF. ALSO TRIMMED POPS BACK INTO
THE LOW END CHANCE/SLIGHT CHANCE CATEGORY WEDNESDAY AFTERNOON AS
THE UPPER SUPPORT TRANSITIONS EAST WITH THE BEST UPGLIDE.
PROBLEMATIC TO THE FORECAST IS THE POTENTIAL FOR SNOW OR A RAIN/SNOW
MIX TUESDAY NIGHT AFTER MIDNIGHT THROUGH THE MORNING HOURS ON
WEDNESDAY...AS THE OPERATIONAL MODELS GENERATE AS MUCH AS FOUR TO
SIX INCHES ACROSS THE SANDHILLS...HOWEVER PROXIMITY SOUNDINGS
INDICATE FACTOR THAT MAY LIMIT OVERALL SNOW PRODUCTION AS THE
DENDRITIC LAYER IS CENTERED NEAR 500MB OVER SOUTHERN AND EASTERN
PORTIONS OF THE CWA /600-700 MB ACROSS THE NORTH AND
NORTHWEST/...AND GIVEN A RATHER SHORT PERIOD OF DEEP TROPOSPHERIC
MOISTURE...SNOW PRODUCTION MAY BE LIMITED. ANOTHER FACTOR AGAINST
ACCUMULATING SNOW IS THE RECENT WARM SPELL...WHICH HAS ALLOWED
GROUND TEMPERATURES TO CLIMB INTO THE 40S. SO FOR NOW WILL GO WITH
LIMITED TO NIL ACCUMULATIONS WITH THE IDEA THAT SUBSEQUENT
FORECASTS WILL HAVE A BETTER IDEA OF WHERE AND IF SNOW
ACCUMULATES.
A STRONG /~1040MB/ SURFACE HIGH WILL BUILD ACROSS THE HIGH PLAINS
EARLY ON THURSDAY AND REMAIN THROUGH FRIDAY MORNING...FROST AND/OR
FREEZE CONDITIONS WILL BE POSSIBLE.
THE UPPER PATTERN BECOMES STALE BY LATE WEEK WITH A CUTOFF LOW
FORMING AND REMAINING SOMEWHERE IN THE VICINITY OF THE LOWER
MISSOURI VALLEY. TEMPERATURES HEADING INTO THE WEEKEND SHOULD
SLOWLY MODERATE ACROSS OUR WESTERN ZONES...WITH THE
EAST...INFLUENCED BY THE UPPER LOW...REMAINING RATHER COOL. THE
LONGER RANGE SOLUTIONS CONTINUE TO INDICATE WRAP AROUND QPF POSSIBLY
AS FAR WEST AS HIGHWAY 61 THROUGH THE WEEKEND. CONFIDENCE IN STALE
PATTERNS USUALLY IS FAIRLY LOW...THUS WON/T MAKE ANY WHOLESALE
CHANGES TO THE EXTENDED PROCEDURE FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 100 PM CDT SUN APR 28 2013
ANOTHER HOT DAY WITH VFR CONDITIONS EXPECTED THIS AFTERNOON. A
WEAK COLD FRONT WILL CAUSE A SLIGHT WIND SHIFT FROM THE
WEST/NORTHWEST TO THE NORTH. WINDS SPEEDS WILL BE SIMILAR BOTH
AHEAD AND BEHIND THE FRONT...GUSTING TO 20 TO 25 KTS. A WEAK
DISTURBANCE WILL MOVE ACROSS THE AREA TONIGHT...AND SHOULD BE
ENOUGH TO SPARK SOME ISOLD/SCT SHOWERS AND THUNDERSTORMS...MAINLY
TO IMPACT NORTHERN NEB. FURTHER SOUTH AN INCREASE OF MID/HIGH
CLOUDS...HOWEVER DRIER LOWER LEVEL ATMOSPHERE SHOULD PREVENT ANY
DEVELOP. SYSTEM MOVES THROUGH QUICKLY WITH VFR AND DRY CONDITIONS
FOR MONDAY...WINDS DO BECOME SOUTHERLY DURING THE LATE MORNING
HOURS.
&&
.FIRE WEATHER...
ISSUED AT 353 AM CDT MON APR 29 2013
LOW PRESSURE DEEPENS ACROSS WRN SD THIS AFTERNOON TO AROUND 990 MB.
THIS SEND ANOTHER SURGE OF WEST/SOUTHWEST WINDS AND VERY DRY AIR
THROUGH THE PANHANDLE AND INTO NCNTL NEB. WINDS SHOULD INCREASE TO
15 TO 25 MPH WITH RH BETWEEN 10 AND 15 PERCENT. GREEN UP IS UNDERWAY
SO FUEL STATUS IS QUESTIONABLE FOR CRITICAL FIRE DANGER ACROSS NWRN
NEB. NO RED FLAG WARNING WILL BE ISSUED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1254 AM CDT MON APR 29 2013
.UPDATE...
ISSUED AT 1251 AM CDT MON APR 29 2013
MINOR ADJUSTMENTS WERE MADE FOR THE OVERNIGHT AS THE FORECAST IS
LARGELY ON TRACK. DEWPOINTS ARE NOT REBOUNDING QUITE AS QUICKLY AS
ANTICIPATED FOR SOME SPOTS OF THE CWA...SO MORE ADJUSTMENTS MAY BE
NEEDED.
UPDATE ISSUED AT 927 PM CDT SUN APR 28 2013
AS OF 02Z RADAR DATA FROM KUEX INDICATES NOTHING IN THE WAY OF
PRECIPITATION OVER OUR CWA. WITH THE LOSS OF DIABATIC HEATING FOR
THE DAY AND POTENTIAL INSTABILITY RAPIDLY DROPPING OFF...PER THE
SPC MESO-ANALYSIS PAGE...THE CHANCES OF CONVECTIVE ACTIVITY BEING
REALIZED ACROSS OUR CWA THIS EVENING ARE QUICKLY DWINDLING. GIVEN
ALL THIS...WENT AHEAD AND PULLED THE ~20% POPS WE PREVIOUSLY HAD
GOING ACROSS OUR NORTHEASTERN CWA THROUGH THIS EVENING. POPS
REMAIN INTACT ACROSS OUR NORTHEAST STARTING AFTER 06Z AS THE
SUBTLE MID LEVEL SHORT WAVE ADVANCES OVER PORTIONS OF THE
REGION...BUT CONVECTIVE ACTIVITY IS NOT CURRENTLY ANTICIPATED WITH
ANY PRECIPITATION AFTER 06Z. THE REMAINDER OF THE FORECAST REMAINS
IN GREAT SHAPE...WITH ONLY SUBTLE CHANGES MADE TO HOURLY
TEMPERATURE...WIND...AND DEWPOINT GRIDS TO BETTER REFLECT CURRENT
OBSERVATIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013
PRIMARY FORECAST CONCERN WILL BE SMALL CHANCES FOR THUNDERSTORMS
LATE THIS AFTERNOON AND EVENING IN THE NORTHEAST PART OF THE CWA
AND THEN ANOTHER SMALL CHANCE FOR SHOWERS IN THE NORTH PART OF THE
CWA OVERNIGHT.
UPPER AIR ANALYSIS AND CURRENT WATER VAPOR IMAGERY SHOW AN UPPER
LEVEL TROUGH MOVING ACROSS THE EASTERN THIRD OF THE COUNTRY WHILE
MORE OF A ZONAL FLOW IS NOTED FROM THE PACIFIC NW INTO THE CENTRAL
PLAINS. THERE ARE A COUPLE OF WEAK SHORT WAVES TO DEAL
WITH...ESPECIALLY ONE MOVING INTO MONTANA WHICH COULD PROVIDE SOME
FORCING ACROSS THE NORTHERN PART OF OUR CWA LATER TONIGHT.
AT THE SURFACE...A TROUGH OF LOW PRESSURE WAS JUST MOVING INTO THE
FAR WESTERN PART OF THE CWA BY 19Z. TEMPERATURES HAVE CLIMBED
STEADILY TODAY AND MOST LOCATIONS SHOULD HIT THE 80S BEFORE THE
AFTERNOON IS OUT. DEW POINTS RANGE FROM THE MID TO UPPER 40S EAST OF
THE SURFACE TROUGH...IN THE MID 30S ALONG THE TROUGH AXIS...AND THEN
DIPPING INTO THE MID 20S 50 TO 100 MILES BEHIND THE TROUGH.
REGARDING FIRE WEATHER CONCERNS...RELATIVE HUMIDITIES HAVE FALLEN
NEAR OR BELOW 20 PERCENT IN THE WEST...BUT WINDS SHOULD STAY BELOW
20 MPH IN THAT PART OF OUR CWA AS THE TROUGH AXIS LIES OVER THAT
AREA. BY THE TIME THE WINDS PICK UP AGAIN FROM THE NW...WE SHOULD BE
A FEW HOURS PAST MAX HEATING.
VARIOUS SHORT RANGE MODELS SHOWING SOME DECENT INSTABILITY AHEAD OF
THE SURFACE TROUGH WHICH COULD TRIGGER CONVECTION LATER THIS
AFTERNOON. BOTH THE HRRR AND THE 4KM WRF SHOWING TSTM DEVELOPMENT IN
THE NORTHEAST PART OF THE CWA FROM ROUGHLY 5 PM THROUGH 10 PM. WHILE
BETTER CHANCES SEEM TO BE JUST A LITTLE FURTHER NORTHEAST THAN OUR
CWA...WILL CONTINUE WITH AT LEAST A SLIGHT CHANCE IN OUR NORTHEAST
AS WE COULD CERTAINLY GET CLIPPED.
THE SHORTWAVE NOTED ABOVE SHOULD HAVE MORE OF AN IMPACT AFTER
MIDNIGHT AND CONTINUED THE CHANCE OF SHOWERS MAINLY IN THE
NORTHEASTERN HALF OF THE CWA. FORCING AND MOISTURE NOT OVERLY
IMPRESSIVE AND WILL KEEP POPS FAIRLY LOW. INSTABILITY ALSO DROPS OFF
QUITE A BIT SO WILL KEEP THUNDER MENTION OUT AFTER MIDNIGHT.
QUIET WEATHER EXPECTED ON MONDAY AS WE AWAIT THE APPROACH OF THE
NEXT SYSTEM UPSTREAM. WITH EASTERLY FLOW AT SURFACE...HIGH
TEMPERATURES SHOULD BE JUST A LITTLE BIT COOLER THAN WHAT WE ARE
SEEING TODAY...BUT ALL IN ALL STILL NOT BAD.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 240 PM CDT SUN APR 28 2013
THE WEATHER PATTERN WILL UNDERGO CHANGES DURING THE EXTENDED PERIODS
WITH A TREND TO COOLER SPRING CONDITIONS.
ON MONDAY NIGHT AN UPPER TROUGH DIGS SOUTH ACROSS THE
NORTHWEST/NORTH CENTRAL TIER STATES AND A SFC COLD FRONTAL BOUNDARY
PUSHES SOUTH FM THE DAKOTAS...AND IS EXPECTED TO STRETCH FM
ROUGHLY KOMA TO KPHG TO SOUTH OF KGLD BY 12Z TUESDAY. WITH FRONT
CROSSING MUCH OF OUR NEB CWA OVERNIGHT...CONSIDERED SOME LOW POPS
TOWARD TUESDAY MORNING BUT CHCS APPEAR HIT OR MISS AND WILL CARRY
SILENT POPS FOR NOW. IN GENERAL...MODELS HAVE CONTINUED TO TREND
FASTER WITH FROPA...WITH THE NAM REMAINING FASTER THAN GFS. THE
FARTHER SOUTH FRONTAL POSITION NEAR THE NEB/KS STATELINE OR IN
NORTHERN KANSAS PLACES CHCS FOR AFTN CONVECTION FARTHER SOUTH AS
WELL. DEPENDING ON TIMING/FRONTAL POSITION THERE STILL APPEARS TO
BE A WINDOW OF OPPORTUNITY...ALBEIT A SHRINKING WINDOW...FOR
POTENTIALLY A STRONG/SEVERE TSTMS IN THE LATE AFTN/EVE FOR OUR
SOUTHEAST ZONES. SOME PRESENCE OF ELEVATED INSTABILITY IS
MAINTAINED INTO THE FIRST PART OF THE NIGHT TUESDAY NIGHT WHICH
SHIFTS SOUTH BY WEDNESDAY MORNING. OVERALL PCPN CHCS INCREASE OVERNIGHT
TUESDAY NIGHT ACROSS OUR ENTIRE CWA IN INCREASING ISENTROPIC LIFT
AHEAD OF THE UPPER TROUGH MOVING ONTO THE CENTRAL PLAINS AND IN
PRESENCE OF STRONG MID LEVEL FRONTOGENESIS. MUCH COLDER AIR
ADVECTS SOUTH BEHIND THE FRONTAL BOUNDARY AND THE R/S LINE ACROSS
WESTERN NEBRASKA LOOKS TO EDGE CLOSE TO OUR NW CWA TOWARDS
WEDNESDAY MORNING.
WEDNESDAY IS SHAPING UP TO BE A COLD...WET...BREEZY/WINDY DAY UNDER
INFLUENCE OF UPPER TROUGH MOVING IN WITH THE BETTER CHCS FOR PCPN
EXPECTED IN THE FIRST PART OF THE DAY BEFORE DRIER AIR ADVECTS IN
FOLLOWING MID LEVEL TROUGH...BUT THIS WILL BE DEPENDENT UPON
SYSTEMN TIMING WITH GFS MORE PROGRESSIVE THAN ECMWF.
MODELS CONTINUE TO DEVIATE ON WHERE UPPER LOW WILL CLOSE OFF
THURS NIGHT/FRI DUE TO A BLOCKING RIDGE TO THE EAST. 24HRS AGO
THE 12Z MODELS CLOSED THE LOW ACROSS THE CENTRAL PLAINS...THEN
THE 00Z SUNDAY RUN OF MODELS CLOSED THE LOW IN EASTERN KS/SOUTHERN
MISSOURI...AND NOW THE 12Z GFS RUN CLOSES THE LOW EAST OF THE
MISSOURI RIVER IN IOWA WITH THE POTENTIAL FOR A CUTOFF SYSTEM TO
LIFT AND RETROGRADE TOWARD THE END OF THE WORKWEEK AND INTO THE
FIRST PART OF NEXT WEEKEND. THE 12Z ECMWF IS A LITTLE MORE SIMILAR
TO ITS PREVIOUS RUN INITIALLY WITH THE SYSTEM CLOSING OFF IN
EASTERN KS WITH THE CUTOFF UPPER LOW MEANDERING ACROSS MISSOURI
THRU THE WEEKEND. PCPN CHCS WILL BE DEPENDENT UPON THE UPPER LOW
PRESSURE SYSTEM POSITION AND IT IS JUST TOO EARLY TO PINPOINT THE
BEST CHCS/TIMING JUST YET GIVEN THE VARYING MODEL SOLUTIONS AND
DID NOT DEVIATE MUCH FROM THE EXTENDED INIT. UNDER THE INFLUENCE
OF THE UPPER LOW/TROUGH PATTERN...TEMPERATURES WILL REMAIN COOL WITH HIGHS
MAINLY 50S...AND LOWS IN THE 30S...ALTHOUGH READINGS COULD RECOVER
SOME IF LOW KICKS OUT TOWARD DAY 7. WITH LOWS IN THE 30S WILL NEED
TO CLOSELY MONITOR POTENTIAL FOR FROST/FREEZE AS SPRING HEADLINES
FOR THIS BEGIN MAY 1.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1251 AM CDT MON APR 29 2013
WIND SPEED SHOULD BE A BIT ELEVATED FROM THE NORTHEAST BEHIND A
COLD FRONT...WHICH SEEMS TO BE FRONTOLYTIC. WIND SHOULD BECOME
NEARLY CALM BY MID-DAY MONDAY AS A TRANSITION TO A SOUTH WIND
OCCURS AS A LEE SIDE TROUGH DEVELOPS TO THE WEST. MAINLY MID-LEVEL
CLOUDINESS IS EXPECTED WITH LOW-LEVELS REMAINING DRY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...EWALD
LONG TERM...FAY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1157 PM CDT SUN APR 28 2013
.UPDATE...
ISSUED AT 558 PM CDT SUN APR 28 2013
CURRENTLY A NARROW LINE OF CONVECTION HAS INITIATED ALONG THE COLD
FRONT IN MINNESOTA FROM RUSH CITY TO MINNEAPOLIS AND ST JAMES.
LAPS ANALYSIS SHOWED MLCAPE VALUES OF 250-600 J/KG...MOSTLY RIGHT
ALONG THE FRONT. KMPX RADAR IMAGERY DOES SUGGEST THAT THE LINE OF
CONVECTION MAY HAVE JUMPED OFF THE FRONT RECENTLY...THOUGH.
MEANWHILE...OVER THE FORECAST AREA...SOME RIDGING HAS BUILT IN
ALOFT PER RAP ANALYSIS...HELPING TO CLEAR SKIES OUT.
PRECIPITATION CHANCES CONTINUE TO BE THE FOCUS TONIGHT. THE
28.12Z REGIONAL CANADIAN AND 28.19/20/21Z HRRR RUNS HAVE BEEN
DOING A GREAT JOB WITH THE CONVECTION ON THE FRONT. ALL OF THESE
MODELS SUGGEST A WEAKENING TREND AS THEY PUSH EAST THROUGH THE
EVENING. THIS MAKES SENSE AS THEY SEEM TO BE DIURNALLY ASSISTED
WITH THE CAPE THAT BUILT AHEAD OF THE FRONT. ONCE DIURNAL COOLING
TAKES PLACE...INSTABILITY WILL WANE AND THUS THE STORMS AS WELL.
PERHAPS A FEW MAY MAKE IT INTO NORTHWEST SECTIONS OF THE FORECAST
AREA...ENOUGH TO WARRANT 20-30 PERCENT CHANCES...LOWER THAN THE
PREVIOUS FORECAST. SEEING SOME OF THE CONVECTION JUMPING OFF THE
FRONT ALSO IS WORRISOME TO HOLD IT TOGETHER BECAUSE INSTABILITY
WANES PRETTY QUICK. THERE COULD BE A GENERALLY DRY PERIOD THEN
UNTIL LATE IN THE NIGHT...WHICH IS WHEN THE COLD FRONT SLIDES INTO
THE AREA. BEHIND THIS FRONT...TWO FORCING MECHANISMS SHOULD HELP
DEVELOP PRECIPITATION...
1. A SHORTWAVE OVER NORTHWEST WYOMING PUSHING EAST INTO EASTERN
SOUTH DAKOTA BY LATE IN THE NIGHT...YIELDING SOME DPVA DOWNSTREAM
INTO NORTHERN IOWA AND SOUTHERN MINNESOTA.
2. MID-LEVEL FRONTOGENESIS IN PLACE BEHIND THE FRONT. RADAR SHOWS
THIS FRONTOGENESIS ALREADY BY A BAND OF SHOWERS FROM NEAR ABERDEEN
SOUTH DAKOTA TO DULUTH MN.
THUS STILL HAVE KEPT SOME HIGHER PRECIPITATION CHANCES FOR LATE IN
THE NIGHT INTO MONDAY MORNING...ESPECIALLY OVER NORTHEAST IOWA
WHERE CONSENSUS EXISTS FROM ALL MODELS FOR PRECIPITATION TO OCCUR.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013
THE MAIN FOCUS FOR TONIGHT INTO MONDAY IS WITH A TWO TIERED SYSTEM
AND THE PRECIPITATION CHANCES THAT COME ALONG WITH IT. THE FIRST
WAVE APPROACHES THE REGION THIS EVENING IN THE FORM OF A SURFACE
COLD FRONT THAT IS CURRENTLY ANALYZED IN WESTERN MINNESOTA. MUCH
OF THE 28.12Z GUIDANCE ARE FORECASTING TOO HIGH OF SURFACE DEW
POINTS...IN THE LOW TO MID 50S WHEN CURRENT OBS SHOW MID
40S...WHICH IN TURN IS MAKING THE INSTABILITY IN THESE MODELS TOO
HIGH. THIS IS CAUSING A LOT OF THE GUIDANCE TO COME UP WITH A
LARGE AREA OF CONVECTION THAT DEVELOPS THIS EVENING AHEAD OF THE
FRONT AND BRINGS IT THROUGH THE REGION IN AN DIMINISHING FASHION
AS THE INSTABILITY WANES OVERNIGHT. THAT TREND IS OKAY...BUT AM
NOT VERY CONFIDENT THAT THIS CONVECTION WILL BE AS WIDESPREAD AS
GUIDANCE SUGGESTS. THE 28.12Z ARW EAST/WEST MODELS SEEM TO DO THE
BEST JOB AT LIMITING THE CLIMBING DEW POINTS AND KEEP 0-3KM MUCAPE
IN THE 200-400 J/KG RANGE OVERNIGHT AND MATCHES BEST TO THESE
THOUGHTS OF MORE SCATTERED THAN WIDESPREAD CONVECTION OVERNIGHT.
WITH JUST A FEW HUNDRED J/KG OF CAPE TO WORK WITH...HAVE LIMITED
THE THUNDER COVERAGE TO BEING ISOLATED TONIGHT. THERE IS SOME
INCREASING MID LEVEL WINDS AS THIS FRONT APPROACHES...SO SHEAR MAY
BE DECENT ENOUGH THAT...COMBINED WITH SOME LOW FREEZING
LEVELS...THERE COULD BE SOME SMALL HAIL THAT OCCURS WITH A FEW OF
THE STORMS BUT NOTHING THAT WOULD BE CONSIDERED SEVERE.
THE MAIN MID LEVEL TROUGH DIVES DOWN ACROSS THE REGION TOMORROW
MORNING AND IS EXPECTED TO DEVELOP A MORE WIDESPREAD AREA OF
CONVECTION ALONG THE WEAKENING SURFACE FRONT. THIS MID LEVEL
TROUGH IS CURRENTLY NOTED ON GOES WATER VAPOR IMAGERY EXTENDING
EAST TO WEST FROM SOUTHWEST ONTARIO INTO SOUTHEAST MONTANA. AS
THIS TROUGH SAGS SOUTHEAST TOMORROW...SOME DIFFERENCES ARISE
BETWEEN THE 28.12Z MESO AND SYNOPTIC SCALE MODELS. THE 28.12Z
NAM/GFS/ECMWF/GEM ALL SHOW SOME STRONG LOW LEVEL MOISTURE
TRANSPORT NOSING UP INTO EASTERN IOWA BY LATE MORNING THAT ALSO
BRING SURFACE DEW POINTS UP INTO THE 60S AHEAD OF THE SURFACE/LOW
LEVEL LOW. THIS BRINGS SFC/0-3KM MUCAPE UP TO ABOVE 2000 J/KG AND
DEVELOPS A WIDESPREAD AREA OF CONVECTION ALONG THE NOSE OF THE LOW
LEVEL JET. MEANWHILE...28.12Z ARW/NMM ARE MUCH MORE TAME WITH THE
MOISTURE RETURN/DEW POINTS/INSTABILITY AND CONVECTIVE DEVELOPMENT.
HAVE KEPT THE LIKELY PRECIPITATION CHANCES GOING FOR NORTHEAST
IOWA/SOUTHWEST WISCONSIN TOMORROW WHERE THIS CONVECTION IS A BIT
MORE CERTAIN...BUT THINK THAT THE SYNOPTIC MODELS ARE A TAD
OVERDONE. IF THE MOISTURE RETURN CAN DEVELOP AS ADVERTISED ON
THESE SYNOPTIC MODELS...WILL HAVE TO WATCH FOR A BRIEF PERIOD OF
SEVERE STORMS THAT COULD PRODUCE SOME LARGE HAIL/GUSTY WINDS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 327 PM CDT SUN APR 28 2013
THE 28.12Z GUIDANCE REMAINS STUBBORN WITH NO DIFFERING TRENDS
NOTED BETWEEN THIS RUN AND THE 28.00Z RUN FOR A COLD FRONT THAT
WILL MOVE THROUGH ON TUESDAY. AHEAD OF THIS FRONT
ON MONDAY NIGHT...THE LOW LEVEL JET/MOISTURE TRANSPORT WILL PUSH
BACK TO THE NORTH AHEAD OF THE FRONT AND COULD SPARK OFF SOME
CONVECTION AS IT LIFTS NORTHWARD. FOR TUESDAY...THE 28.12Z ECMWF
REMAINS THE SLOW OUTLIER WITH THE EASTWARD PROGRESSION OF THE
SURFACE COLD FRONT ON TUESDAY AND PRESENTS THE WARMEST SOLUTION
FOR TEMPERATURES. BY 00Z WEDNESDAY...THE 28.12Z NAM/GFS BOTH HAVE
THIS FRONT INTO NORTHWEST ILLINOIS WHILE THE ECMWF STILL HAS IT
BACK IN NORTHWEST WISCONSIN/JUST CLEARING SOUTHEAST MINNESOTA.
WITH LOW LEVEL MOISTURE TRANSPORT INCREASING AHEAD OF THIS FRONT
ON TUESDAY AND DECENT LOW LEVEL LIFT ALONG THE FRONT...SOME SEVERE
WEATHER IS POSSIBLE IN THE WARM SECTOR TUESDAY. WHERE THAT WARM
SECTOR IS ALIGNED BY MID AFTERNOON IS UNCERTAIN STILL...BUT WILL
HAVE TO WATCH FOR WHICH WAY THIS FRONT TRENDS. DUE TO THERE NOT
BEING MUCH IN THE WAY OF CHANGES IN THE GUIDANCE...HAVE NOT MADE
MANY ADJUSTMENTS TO THE GOING FORECAST OVER THIS PERIOD.
AFTER THIS COLD FRONT MOVES THROUGH BY TUESDAY NIGHT IT WILL THEN
STALL OUT TO THE EAST OF THE REGION AS A MID TO UPPER LEVEL TROUGH
AMPLIFIES ACROSS THE CENTRAL US TOWARD THE MIDDLE OF THE WEEK.
THIS TROUGH GETS CUT OFF FROM THE FLOW WITH THE CORE OF THE LOW
SITTING RIGHT OVER THE UPPER MISSISSIPPI RIVER VALLEY THROUGH NEXT
WEEKEND. STRONG FORCING WILL DEVELOP ON WEDNESDAY IN RESPONSE TO
A STRENGTHENING LOW TO MID LEVEL BAND OF FRONTOGENESIS THAT FORMS
TO THE WEST OF THE SURFACE FRONT. WHILE THE 28.12Z ECMWF CONTINUES
TO BE AN OUTLIER WITH A WARMER SOLUTION FROM 700MB DOWN TO THE
SURFACE ON WEDNESDAY AND WANTS TO KEEP THE PRECIPITATION AS
MAINLY RAIN TO BEGIN...IT DOES APPEAR TO BE COMING AROUND TO BEING
COLD ENOUGH TO PRODUCE ALL SNOW FROM WEDNESDAY NIGHT INTO EARLY
THURSDAY. THIS IS ESPECIALLY THE CASE ACROSS SOUTHEAST MINNESOTA
AND NORTHEAST IOWA WHERE SOME SIGNIFICANT SNOW RATES AND
ACCUMULATIONS ARE POSSIBLE. 28.12Z GFS THERMAL PROFILES SHOW THAT
THE MAIN QUESTION IS WITH SURFACE TEMPERATURES AND HOW MUCH THEY
WILL COOL AS THE PRECIPITATION COMMENCES ON WEDNESDAY. THE HIGHEST
CONFIDENCE FOR ANY SNOW ACCUMULATION AT THIS POINT IS WEDNESDAY
NIGHT INTO THURSDAY MORNING AS THE COLDEST LOW LEVEL AIR COMES IN.
CURRENT FORECAST TEMPERATURES FOR WEDNESDAY INTO THURSDAY MAY END
UP BEING TOO HIGH...BUT FOR NOW HAVE DONE A SEMI-BLEND OF THE
28.12Z GFS/ECMWF.
BEYOND THIS FEATURE...THE 28.12Z GFS IS FASTER WITH CLEARING OUT
THE PRECIPITATION ON THURSDAY COMPARED TO THE ECMWF AND GEM WHICH
LINGER THE FRONTOGENETIC BAND OVER THE REGION THROUGH THE REST OF
THE WEEK AS THE MID LEVEL LOW GETS CUT OFF FROM THE FLOW. THIS MID
LEVEL AND SURFACE LOW RETROGRADE BACK INTO IOWA/MISSOURI BY NEXT
WEEKEND...WHICH MAY HELP TO BRING SOME SLIGHTLY WARMER AIR BACK
INTO THE REGION. OVERALL...EXPECTING PERIODS OF PRECIPITATION AS
THIS LOW SITS AND SPINS WITH SHORTWAVE TROUGHS ROTATING AROUND IT
THROUGH NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1157 PM CDT SUN APR 28 2013
CONFIDENCE REMAINS LOW FOR THE AVIATION FORECAST...PRIMARILY ON IF
PRECIPITATION WILL IMPACT THE TAF SITES. AS OF 05Z...A BAND OF
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS STRETCHED FROM NORTHWEST
IOWA TO THE EAU CLAIRE AREA. THIS BAND SHOULD SINK SOUTH WITH
TIME...BUT THERE ARE CONFLICTING SIGNALS AS TO ITS SPEED AND
WHETHER IT WILL HOLD TOGETHER. A STRONGER SIGNAL SHOWS UP IN THE
12-18Z TIME PERIOD OF AN AREA OF SHOWERS AND SOME THUNDERSTORMS
FORMING OVER NORTHERN IOWA AND MARCHING NORTHEAST...POSSIBLY
CLIPPING THE TAF SITES. HAVE KEPT THE VCSH GOING BECAUSE OF THE
UNCERTAINTY...RUNNING FROM 06Z-15Z AT KRST AND 09-21Z AT KLSE.
EVEN IF SHOWERS IMPACT THE TAF SITES...CONDITIONS LOOK TO STAY
VFR. THE BIGGER CONCERN WOULD BE ANY THUNDERSTORMS...BUT GIVEN THE
ISOLATED NATURE OF THEM AND THE UNCERTAINTY ON SHOWERS IMPACTING
THE TAF SITES...HAVE NOT INCLUDED ANY THUNDER IN THE TAFS. DRYING
CONDITIONS LOOK TO TAKE HOLD FOR THE LATE AFTERNOON AND EVENING
HOURS AS THE FORCING FOR PRECIPITATION SHIFTS OFF TO THE EAST.
THE VFR CLOUDS IN PLACE MAY EVEN BREAK UP DURING THIS TIME.
ONE SIDE NOTE IS THAT BETWEEN NOW AND 09Z...CONDITIONS ARE
MARGINAL FOR LOW LEVEL WIND SHEAR AT KLSE. A SOUTHWESTERLY 30-35
KT JET EXISTS BETWEEN 1000-1500 FT AGL DURING THIS TIME. HAVE NOT
INCLUDED THE LOW LEVEL WIND SHEAR DUE TO AGAIN THE MARGINAL
NATURE.
&&
.HYDROLOGY...
ISSUED AT 327 PM CDT SUN APR 28 2013
POTENTIAL EXISTS FOR SOME HEAVY RAINFALL THIS WEEK AS A SYSTEM
STALLS OUT ACROSS THE REGION TOWARD MID WEEK. THERE IS SOME
QUESTION ABOUT WHAT THE PRECIPITATION TYPE WILL BE...BUT THE
FORECAST GUIDANCE IS SUGGESTING RAINFALL AMOUNTS OF OVER AN INCH
BY THE END OF THE WEEK. SHOULD THIS PRECIPITATION FALLS AS
RAIN...THERE COULD BE AN INCREASE IN LOCAL RIVER LEVELS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1121 AM EDT MON APR 29 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST ACROSS THE MID ATLANTIC TODAY AND OFF
THE COAST TONIGHT. LOW PRESSURE LINGERS OFF THE CAROLINA COAST
THROUGH MIDWEEK AS HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT RADAR TRENDS SHOWING PRECIP CONTINUING TO MOVE E/NE THIS
MORNING...WITH AREAS WEST OF RIC BEGINNING TO SEE SOME BREAKS IN THE
PRECIP. HAVE UPDATED POPS TO SHOW THIS TREND...BUT HAVE KEPT 30-50
PERCENT CHANCE OF PRECIP IN THE WEST TO ACCOUNT FOR -SHRA
DEVELOPMENT THIS AFTERNOON. OTHERWISE FORECAST LOOKS ON TARGET.
...PREVIOUS DISCUSSION...
THE LATEST RUC MAINTAINS THIS STRONG LIFT OVER THE LOCAL AREA
THROUGH 12Z BEFORE SHIFTING IT TOWARD THE EASTERN PORTION OF THE
AREA FROM 12-16Z AS THE JET CORE PULLS NE TOWARD LONG ISLAND AND
THE MID-LEVEL TROUGH AXIS INTRUDES FROM THE WEST. THIS SHOULD
ALLOW STEADY RAIN TO SLOWLY TAPER OFF W OF I-95 THROUGH THE
MORNING. THE MAIN AREA OF ASCENT THEN SHIFTS TO SE PORTIONS BY
AFTERNOON AS A SECONDARY SPEED MAX MOVES OVER CENTRAL VA. A FEW
RUMBLES OF THUNDER ARE POSSIBLE OVER SE PORTIONS GIVEN THAT THIS
FEATURE ARRIVES DURING THE AFTERNOON. HOWEVER...AMBIENT RAIN
COOLED STABLE CONDITIONS WILL LIMIT INSTABILITY (AND LIMIT THE
POTENTIAL OF DEEP CONVECTION) HENCE THUNDER WILL NOT BE INCLUDED
IN THE GRIDS. THE LATEST DATA SUGGESTS THAT QPF COULD REACH 1.5IN
AND POSSIBLY CLOSE TO 2.0IN FOR SOME LOCATIONS BY THIS AFTERNOON
ACROSS S-CENTRAL/SE VA/EASTERN SHORE/NE NC. THIS HAS FURTHER
SUPPORT FROM UPSTREAM OBS OVER CENTRAL NC WHERE AMOUNTS HAVE
REACHED 1.0-1.5IN AND RAIN CONTINUES.
THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST TONIGHT WITH THE
ASSOCIATED WIND FLOW BECOMING NW (ALBEIT WEAK). THIS SHOULD ALLOW
STEADY RAIN TO TAPER OFF TO SHOWERS THIS EVENING FOR EASTERN AREAS.
THERE IS AN ABUNDANT AMOUNT OF LINGERING LOW-LEVEL MOISTURE THAT
WILL NOT BE SCOURED OUT BY WEAK FLOW...SO WIDESPREAD STRATUS IS
EXPECTED TO DEVELOP. THIS COULD EVENTUALLY SETTLE TO THE SURFACE
RESULTING IN THE POTENTIAL FOR FOG.
CLOUD COVER AND RAIN WILL LIMIT HIGH TEMPERATURES TODAY...WITH
READINGS RANGING FROM THE LOW/MID 60S (UPPER 50S ALONG THE ATLANTIC
COAST) OVER THE EASTERN SHORE TO THE UPPER 60S/NEAR 70 S. LOWS
TONIGHT WILL BE MILD AND LARGELY BE IN THE MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
HIGH PRESSURE RE-EXERTS ITSELF OVER THE CANADIAN MARITIMES TUESDAY
AND WEDNESDAY AND NUDGES SW ALONG THE NEW ENGLAND COAST.
MEANWHILE...A COASTAL TROUGH LINGERS OFF THE CAROLINA COAST. THIS
WILL MAINTAIN ONSHORE FLOW AND PERSISTENT MOSTLY CLOUDY TO OVERCAST
CONDITIONS. THE LATEST GFS/NAM/ECMWF DRAW MOISTURE AROUND THE
NORTHERN PERIPHERY OF THE TROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
AHEAD OF A BACKDOOR FRONT. HOWEVER...CONFIDENCE IS LOW REGARDING
RAIN POTENTIAL AT THIS TIME...SO WILL GO WITH NO HIGHER THAN A 40
POP. THUNDER POTENTIAL SHOULD REMAIN VERY LIMITED DUE TO ONSHORE
FLOW AND SSTS IN THE LOW/MID 50S. IF ANY THUNDER WERE TO OCCUR
(MAINLY TUE) IT WOULD BE OVER INTERIOR NE NC AND S-CENTRAL VA.
AS FOR TEMPERATURES...THE COOLER MAV GUIDANCE HAS BEEN FOLLOWED AS
MET NUMBERS APPEAR TOO WARM BASED ON EXPECTED CLOUD COVER. THIS
RESULTS IN HIGHS TUESDAY RANGING FROM THE LOW/MID 60S OVER THE
EASTERN SHORE...TO THE LOW 70S ALONG AND S OF THE VA/NC BORDER (AWAY
FROM THE COASTS). HIGHS WEDNESDAY SHOULD BE A FEW DEGREES COOLER
RANGING FROM THE LOW 60S OVER THE EASTERN SHORE (PERHAPS UPPER 50S
ALONG THE COAST) THE THE UPPER 60S S. LOW TEMPERATURES SHOULD REMAIN
IN THE 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
WIDESPREAD RAIN CONTINUES ACRS THE LOCAL AREA THIS MORNING, WITH
IFR/MVFR (LCL LIFR IVOF SBY BETWEEN 12-15Z) TO LINGER THROUGH THE
DAY, AS LOW PRESSURE CONTINUES TO BRING RAIN TO THE AREA. EXPECT
CIGS TO BOUNCE BACK SOME BY THIS AFTN, AT LEAST TO HIGH END MVFR
AT RIC (POTENTIALLY VFR AFTER 18-20Z). OTHERWISE, SUB-VFR CONDS
PERSIST THROUGH THE TAF PERIOD AT COASTAL SITES, REMAINING IN
IFR-MVFR RANGE THROUGH THE DAY AT SBY-PHF-ORF-ECG. PCPN WL SLOWLY
TAPER OFF FROM WEST TO EAST TONIGHT BUT MAY NEVER TOTALLY END AT
THE COASTAL SITES UNTIL LATE TONIGHT.
OUTLOOK...DESPITE PCPN ENDING, DIMINISHING WINDS AND PLENTY OF
REMNANT LLVL MOISTURE SEEM TO POINT TOWARDS A RETURN OF IFR/LIFR
OVERNIGHT IN LOW CLOUDS/FOG OVERNIGHT. CONDITIONS DO GRADUALLY
IMPROVE ON TUESDAY. HOWEVER, PERSISTENT NE FLOW SHOULD RESULT IN
OCCASIONAL RAIN SHOWERS WITH LINGERING LOW CLOUDS, ESPECIALLY AT
COASTAL TERMINALS TUE/WED.
&&
.MARINE...
LOW PRESSURE APPROACHES THE AREA FROM THE WEST TODAY...THEN WEAKENS
AS IT CROSSES THE WATERS TONIGHT. LIGHT SE FLOW OVER THE WATERS
EARLY THIS MORNING WILL INCREASE DURING THE DAY TODAY DUE TO AN
INCREASING PRESSURE GRADIENT...ALLOWING FOR WINDS OF 15-20 KNOTS
OVER THE WATERS WITH SOME GUSTS UP TO 25 KT ON THE OCEAN. THE
EASTERLY COMPONENT TO THE WINDS WILL ALLOW SEAS TO BUILD ON THE
OCEAN...REACHING 5-6 BY LATE MORNING. SCA`S REMAIN IN PLACE FOR ALL
THE COASTAL WATERS (MAINLY FOR SEAS) TODAY THRU TUESDAY NIGHT. SCA`S
FOR THE CHES BAY/CURRITUCK SOUND CONTINUE THRU 7 PM THIS EVENING
WHEN THE PRESSURE GRADIENT SHOULD RELAX AND WINDS SUBSIDE. SFC HIGH
PRESSURE REMAINS LOCKED IN PLACE OVER NEW ENGLAND THRU THE COMING
WEEK ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS.
ALTHOUGH WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS
WILL REMAIN AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE
WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>634.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT WEDNESDAY FOR ANZ650-652-
654-656-658.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/DAP
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/MAM
MARINE...JDM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1057 AM EDT MON APR 29 2013
.SYNOPSIS...
ONE MORE UNSETTLED WEATHER DAY BEFORE HIGH PRESSURE TAKES CHARGE.
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC AND CONTROLS OUR
WEATHER THROUGH THE WEEKEND. THE MIDDLE TO LATTER PART OF THE
WORK WEEK WILL BE THE WARMEST WITH TEMPERATURES 10 DEGREES ABOVE
NORMAL. COME THE WEEKEND...LOOK FOR HIGHS TO FALL BACK TO SEASONAL
NUMBERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCATTERED TO NUMEROUS SHOWERS CONTINUE EAST OF THE OHIO RIVER.
HIGHEST POPS WILL REMAIN THERE THROUGH THE AFTERNOON. FOG IS SLOWLY
LIFTING BASED ON AREA WEB CAMS AND SFC REPORTING SITES IN GARRETT
COUNTY...SO NO NEED TO EXTEND FOG. SKY COVER AND RESULTANT
DAYTIME MAXT ARE THE MAIN FORECAST CHALLENGES. LATEST HRRR CLOUD
COVERAGE PROGS ILLUSTRATES SCT-BKN OPEN CELLULAR CLOUDS ACROSS THE
ENTIRE REGION THIS AFTERNOON ALLOWING THE MERCURY TO CLIMB INTO
THE L-M 60S. THIS CONCURS WITH EXISTING FORECAST...SO ONLY TWEAKS
NEEDED. IT ONLY TAKES A SHORT DURATION OF SUNSHINE TO JUMP TEMPS
INTO THE MID 60S /CASE IN POINT CENTRAL WV ALONG THE OHIO RIVER/.
AS TROUGH AXIS PASSES INTO CENTRAL PENNSYLVANIA THIS EVENING...CHANCE
FOR RAIN SHOULD RAPIDLY DECREASE. HOWEVER...ONLY EXPECT TO SEE
PARTIAL CLEARING WITH FLOW REMAINING OUT OF THE EAST-SOUTHEAST
BRINGING IN MOISTURE FROM THE ATLANTIC OCEAN. PARTLY CLOUDY SKIES
WILL KEEP TEMPERATURES FROM FALLING TOO MUCH...WHICH WILL KEEP
OVERNIGHT LOWS ABOVE GUIDANCE. WITH MOISTURE DEPTH AND AREAS THAT
EXPERIENCE PARTIAL CLEARING...PATCHY FOG WILL BE A CONCERN.
PARCEL TRAJECTORIES TONIGHT ARE FROM IND WHERE WIDESPREAD STRATUS
EXISTS.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
UPPER LEVEL HIGH WILL BEGIN TO ESTABLISH ITSELF ACROSS THE EAST
COAST DURING THE MIDDLE OF THE WORK WEEK WHILE BROAD UPPER LEVEL
TROUGH WILL REMAIN ACROSS THE WESTERN HALF OF THE UNITED STATES.
THIS WILL KEEP WIDESPREAD PRECIPITATION AWAY FROM THE REGION.
HOWEVER...EASTERLY LOW LEVEL FLOW WILL CONTINUE THROUGH THE
PERIOD...WITH ATLANTIC MOISTURE BRINGING CLOUDS AND RAIN EAST OF THE
LAUREL HIGHLANDS. THIS PATTERN SHOULD MANAGE TO KEEP SKIES AT LEAST
PARTLY CLOUDY...AND AN ISOLATED SHOWER CANNOT BE RULED OUT RIGHT
ALONG THE RIDGES. DURING THESE TWO DAYS...TEMPERATURES WILL REMAIN
NEAR NORMAL IN THE CLOUDY EASTERN COUNTIES...AND TEMPERATURES UP TO
10 DEGREES ABOVE NORMAL ARE EXPECTED IN THE SUNNIER WESTERN COUNTIES
OUT IN OHIO.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MODELS STILL IN GENERAL AGREEMENT ON A BLOCKED UPPER LEVEL
PATTERN THROUGH THE EXTENDED AS A POWERFUL COLD CLOSED LOW DIVES
INTO THE NATIONS MID SECTION WITH A CLOSED RIDGE ALOFT ACROSS THE
NORTHEASTERN STATES. NOT A GREAT DEAL OF CHANGE TO PREVIOUS
FORECAST WITH EAST COAST HIGH PRESSURE KEEPING REGION DRY THROUGH
THE WORK WEEK. BY THE WEEKEND MODELS DO DIFFER ON HOW FAST
BLOCKED PATTERN WILL BREAK. A COMPROMISE SOLUTION TOWARD THE HPC
GRIDS BRINGS IN A CHANCE FOR SHOWERS MAINLY SUNDAY AS OCCLUDED
FRONTAL BOUNDARY MOVES INTO REGION AS RIDGE WEAKENS AND CLOSED LOW
BEGINS TO SHIFT EAST. TEMPERATURES WILL TREND BACK TOWARD NORMAL
BY THE WEEKEND.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
MVFR CIGS WILL BE THE RULE THROUGH THE AFTERNOON. MVFR VIS
RESTRICTIONS COULD OCCUR AT FKL/DUJ/PIT/LBE WITH A PASSING SHOWER
THROUGH 21Z. CIGS WILL LIFT TO VFR THIS EVENING AS HIGH PRESSURE
SLOWLY WORKS INTO THE REGION.
LOWER CONFIDENCE ON VIS AND CIGS DURING THE PREDAWN HOURS.
DEPENDING HOW MANY TERMINALS CLEAR OUT WILL DETERMINE HOW
WIDESPREAD OR PATCHY THE FOG IS. IF CLEARING DOES NOT OCCUR
TONIGHT...NEITHER WOULD IFR WX. AFTER ANY MORNING FOG LIFTS LOOK
FOR VFR CONDS TUE.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
NO WIDESPREAD IFR WEATHER FORECAST.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
SYNOPSIS...98
NEAR TERM...98/34
SHORT TERM...34
AVIATION...98
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
759 AM EDT MON APR 29 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST ACROSS THE MID ATLANTIC TODAY AND OFF
THE COAST TONIGHT. LOW PRESSURE LINGERS OFF THE CAROLINA COAST
THROUGH MIDWEEK AS HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT WATER VAPOR IMAGERY INDICATES A MOIST FRONTAL BAND EXTENDING
FROM THE NORTHERN GULF COAST THROUGH THE MID ATLANTIC AHEAD OF A
MID-LEVEL TROUGH OVER THE OHIO VALLEY. VIGOROUS VERTICAL ASCENT...IN
THE RRQ OF AN 85KT JET CORE OVER THE SUSQUEHANNA VALLEY OF PA (PER
29/06Z RUC) HAS RESULTED IN WIDESPREAD RAIN FROM FROM SC TO NJ AS OF
0730Z. THE LATEST RUC MAINTAINS THIS STRONG LIFT OVER THE LOCAL AREA
THROUGH 12Z BEFORE SHIFTING IT TOWARD THE EASTERN PORTION OF THE
AREA FROM 12-16Z AS THE JET CORE PULLS NE TOWARD LONG ISLAND AND THE
MID-LEVEL TROUGH AXIS INTRUDES FROM THE WEST. THIS SHOULD ALLOW
STEADY RAIN TO SLOWLY TAPER OFF W OF I-95 THROUGH THE MORNING. THE
MAIN AREA OF ASCENT THEN SHIFTS TO SE PORTIONS BY AFTERNOON AS A
SECONDARY SPEED MAX MOVES OVER CENTRAL VA. A FEW RUMBLES OF THUNDER
ARE POSSIBLE OVER SE PORTIONS GIVEN THAT THIS FEATURE ARRIVES DURING
THE AFTERNOON. HOWEVER...AMBIENT RAIN COOLED STABLE CONDITIONS WILL
LIMIT INSTABILITY (AND LIMIT THE POTENTIAL OF DEEP CONVECTION) HENCE
THUNDER WILL NOT BE INCLUDED IN THE GRIDS. THE LATEST DATA SUGGESTS
THAT QPF COULD REACH 1.5IN AND POSSIBLY CLOSE TO 2.0IN FOR SOME
LOCATIONS BY THIS AFTERNOON ACROSS S-CENTRAL/SE VA/EASTERN SHORE/NE
NC. THIS HAS FURTHER SUPPORT FROM UPSTREAM OBS OVER CENTRAL NC WHERE
AMOUNTS HAVE REACHED 1.0-1.5IN AND RAIN CONTINUES.
THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST TONIGHT WITH THE
ASSOCIATED WIND FLOW BECOMING NW (ALBEIT WEAK). THIS SHOULD ALLOW
STEADY RAIN TO TAPER OFF TO SHOWERS THIS EVENING FOR EASTERN AREAS.
THERE IS AN ABUNDANT AMOUNT OF LINGERING LOW-LEVEL MOISTURE THAT
WILL NOT BE SCOURED OUT BY WEAK FLOW...SO WIDESPREAD STRATUS IS
EXPECTED TO DEVELOP. THIS COULD EVENTUALLY SETTLE TO THE SURFACE
RESULTING IN THE POTENTIAL FOR FOG.
CLOUD COVER AND RAIN WILL LIMIT HIGH TEMPERATURES TODAY...WITH
READINGS RANGING FROM THE LOW/MID 60S (UPPER 50S ALONG THE ATLANTIC
COAST) OVER THE EASTERN SHORE TO THE UPPER 60S/NEAR 70 S. LOWS
TONIGHT WILL BE MILD AND LARGELY BE IN THE MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
HIGH PRESSURE RE-EXERTS ITSELF OVER THE CANADIAN MARITIMES TUESDAY
AND WEDNESDAY AND NUDGES SW ALONG THE NEW ENGLAND COAST.
MEANWHILE...A COASTAL TROUGH LINGERS OFF THE CAROLINA COAST. THIS
WILL MAINTAIN ONSHORE FLOW AND PERSISTENT MOSTLY CLOUDY TO OVERCAST
CONDITIONS. THE LATEST GFS/NAM/ECMWF DRAW MOISTURE AROUND THE
NORTHERN PERIPHERY OF THE TROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
AHEAD OF A BACKDOOR FRONT. HOWEVER...CONFIDENCE IS LOW REGARDING
RAIN POTENTIAL AT THIS TIME...SO WILL GO WITH NO HIGHER THAN A 40
POP. THUNDER POTENTIAL SHOULD REMAIN VERY LIMITED DUE TO ONSHORE
FLOW AND SSTS IN THE LOW/MID 50S. IF ANY THUNDER WERE TO OCCUR
(MAINLY TUE) IT WOULD BE OVER INTERIOR NE NC AND S-CENTRAL VA.
AS FOR TEMPERATURES...THE COOLER MAV GUIDANCE HAS BEEN FOLLOWED AS
MET NUMBERS APPEAR TOO WARM BASED ON EXPECTED CLOUD COVER. THIS
RESULTS IN HIGHS TUESDAY RANGING FROM THE LOW/MID 60S OVER THE
EASTERN SHORE...TO THE LOW 70S ALONG AND S OF THE VA/NC BORDER (AWAY
FROM THE COASTS). HIGHS WEDNESDAY SHOULD BE A FEW DEGREES COOLER
RANGING FROM THE LOW 60S OVER THE EASTERN SHORE (PERHAPS UPPER 50S
ALONG THE COAST) THE THE UPPER 60S S. LOW TEMPERATURES SHOULD REMAIN
IN THE 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
WIDESPREAD RAIN CONTINUES ACRS THE LOCAL AREA THIS MORNING, WITH
IFR/MVFR (LCL LIFR IVOF SBY BETWEEN 12-15Z) TO LINGER THROUGH THE
DAY, AS LOW PRESSURE CONTINUES TO BRING RAIN TO THE AREA. EXPECT
CIGS TO BOUNCE BACK SOME BY THIS AFTN, AT LEAST TO HIGH END MVFR
AT RIC (POTENTIALLY VFR AFTER 18-20Z). OTHERWISE, SUB-VFR CONDS
PERSIST THROUGH THE TAF PERIOD AT COASTAL SITES, REMAINING IN
IFR-MVFR RANGE THROUGH THE DAY AT SBY-PHF-ORF-ECG. PCPN WL SLOWLY
TAPER OFF FROM WEST TO EAST TONIGHT BUT MAY NEVER TOTALLY END AT
THE COASTAL SITES UNTIL LATE TONIGHT.
OUTLOOK...DESPITE PCPN ENDING, DIMINISHING WINDS AND PLENTY OF
REMNANT LLVL MOISTURE SEEM TO POINT TOWARDS A RETURN OF IFR/LIFR
OVERNIGHT IN LOW CLOUDS/FOG OVERNIGHT. CONDITIONS DO GRADUALLY
IMPROVE ON TUESDAY. HOWEVER, PERSISTENT NE FLOW SHOULD RESULT IN
OCCASIONAL RAIN SHOWERS WITH LINGERING LOW CLOUDS, ESPECIALLY AT
COASTAL TERMINALS TUE/WED.
&&
.MARINE...
LOW PRESSURE APPROACHES THE AREA FROM THE WEST TODAY...THEN WEAKENS
AS IT CROSSES THE WATERS TONIGHT. LIGHT SE FLOW OVER THE WATERS
EARLY THIS MORNING WILL INCREASE DURING THE DAY TODAY DUE TO AN
INCREASING PRESSURE GRADIENT...ALLOWING FOR WINDS OF 15-20 KNOTS
OVER THE WATERS WITH SOME GUSTS UP TO 25 KT ON THE OCEAN. THE
EASTERLY COMPONENT TO THE WINDS WILL ALLOW SEAS TO BUILD ON THE
OCEAN...REACHING 5-6 BY LATE MORNING. SCA`S REMAIN IN PLACE FOR ALL
THE COASTAL WATERS (MAINLY FOR SEAS) TODAY THRU TUESDAY NIGHT. SCA`S
FOR THE CHES BAY/CURRITUCK SOUND CONTINUE THRU 7 PM THIS EVENING
WHEN THE PRESSURE GRADIENT SHOULD RELAX AND WINDS SUBSIDE. SFC HIGH
PRESSURE REMAINS LOCKED IN PLACE OVER NEW ENGLAND THRU THE COMING
WEEK ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS.
ALTHOUGH WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS
WILL REMAIN AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE
WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>634.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT WEDNESDAY FOR ANZ650-652-
654-656-658.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/MAM
MARINE...JDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1203 PM EDT MON APR 29 2013
.SYNOPSIS...
ISSUED AT 344 AM EDT MON APR 29 2013
AREAS OF FOG WILL BE FOUND EARLY THIS MORNING...ESPECIALLY ACROSS
AREAS NEAR AND SOUTH OF I-69. ONCE THE FOG DISSIPATES...MOST AREAS
SHOULD WARM UP NICELY TO AROUND 70 WITH A DECENT AMOUNT OF SUNSHINE.
THERE WILL BE A CHANCE OF SHOWERS UP NORTH THIS AFTERNOON.
A CHANCE OF SHOWERS AND STORMS WILL EXIST TONIGHT AND INTO TUESDAY
AS A WAVE OF LOW PRESSURE AND A SURGE OF WARMER AND MORE MOIST AIR
MOVES TOWARD THE AREA.
A FRONT EXPECTED TO NEARLY STALL OUT TO OUR WEST TUESDAY AND
WEDNESDAY WILL TRY TO LEAN INTO THE AREA ON THURSDAY AND INCREASE
THE CHANCE FOR SHOWERS AND STORMS. MUCH OF THE AREA COULD SEE THEIR
FIRST 80 DEGREE TEMPERATURE OF THIS SPRING ON TUESDAY AND/OR
WEDNESDAY.
&&
.UPDATE...
ISSUED AT 1202 PM EDT MON APR 29 2013
SHORTWAVE TROUGH IS PUSHING FROM MINNESOTA INTO WISCONSIN AT
MIDDAY WITH A SURFACE COLD FRONT LOCATED AHEAD OF IT STRETCHING
FROM WISCONSIN SOUTHWEST INTO IOWA. A BAND OF SHOWERS AND A FEW
EMBEDDED THUNDERSTORMS WERE LOCATED NEAR THE FRONT.
HI-RES WRF MODELS (NSSL AND SPC) AND THE HRRR KEEP THE BULK OF THE
PRECIPITATION TO THE NORTH AND WEST OF THE FORECAST AREA THIS
AFTERNOON. SOME SCATTERED SHOWER ACTIVITY IS POSSIBLE ACROSS ABOUT
THE NORTHERN THIRD OF THE FORECAST AREA AND HAVE MAINTAINED POPS
IN THE FORECAST UP THERE. THROUGH THE AFTERNOON...THE BEST
MOISTURE RETURN AND LIFT SHOULD BE WEST AND NORTH OF THE FORECAST
AREA. THE UPSTREAM SURFACE COLD FRONT ACTUALLY WASHES OUT WITH
TIME OVER ABOUT THE NEXT 18 HOURS AS NEW MID LEVEL ENERGY TAKES
OVER FROM THE WEST.
THE SHOWER AND POSSIBLY SOME THUNDERSTORM ACTIVITY DOES TRY TO
SPILL INTO THE CWA THIS EVENING AND TONIGHT. IT APPEARS THE
NORTHERN CWA MAY SEE PRECIPITATION THIS EVENING...SPREADING INTO
WESTERN PORTIONS OF THE FORECAST OVERNIGHT.
HIGH TEMPERATURES WILL MAKE A RUN INTO THE LOWER TO MIDDLE 70S AT
MOST LOCATIONS WITH COOLER READINGS NEAR LAKE MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 344 AM EDT MON APR 29 2013
FORECAST CONCERNS WITH THE SHORT TERM INCLUDE FOG ISSUES THIS
MORNING AND PCPN TRENDS THROUGH THE PERIOD.
WE HAVE ISSUED A DENSE FOG ADVISORY FOR THE SE CORNER OF THE CWFA
FOR THIS MORNING. OBS AT KJXN...KTEW...KRMY...AND EVEN AT KLAN ARE
ALL AT OR HAVE BEEN AT 1/4SM EARLY THIS MORNING. THESE LOCATIONS
HAVE SEEN THE WORST CONDITIONS AS A RESULT OF THE BETTER RAINFALL
THAT OCCURRED ON SUNDAY. THE WORST VISIBILITIES SEEM TO ALIGN VERY
WELL WITH THE PLACES THAT SAW THE MOST RAIN PER THE KGRR STORM TOTAL
PCPN PRODUCT. WE HAVE KALAMAZOO COUNTY AND EATON COUNTY IN THE
ADVISORY EVEN THOUGH NO OBS OFFICIALLY SUPPORT FOG YET. DUE TO THE
RAINFALL PLACEMENT ON SUN...WE THINK THERE IS A GOOD CHANCE
LOCATIONS IN THESE COUNTIES ARE SEEING ENOUGH FOG TO JUSTIFY THE
ADVISORY THERE.
AS FAR AS PCPN TRENDS ARE CONCERNED...WE HAVE GENERALLY TRENDED THE
CHCS LOWER JUST A LITTLE THROUGH WED AS IT SEEMS LIKE THE FRONT WILL
GET HELD UP A LITTLE FURTHER WEST THAN PREVIOUSLY INDICATED. WE
BELIEVE THIS IS THE CASE SINCE THE MAIN TROUGH THAT FORMS THE UPPER
LOW DIGS A LITTLE FURTHER SOUTH AND WEST...HELPING TO BUILD THE
RIDGE CLOSER TO MI.
WE WILL SEE THE INITIAL FRONT NOW MAKING ITS WAY PAST KMSP AND INTO
WI. THIS FRONT IS EXPECTED TO STALL OUT SOON AS IT ALIGNS WITH THE
MID LEVEL FLOW. THE CONVECTION WITH IT SHOULD STAY CLOSE TO IT...AND
CLOUD SNEAK INTO THE NW CORNER OF THE CWFA LATER TODAY. WE BELIEVE
THAT MOST OF IT SHOULD REMAIN NW OF THE CWFA. THE FRONT WILL
GRADUALLY WASH OUT TONIGHT.
WE WILL SEE A SURGE OF WARM AND MOIST AIR ALOFT TONIGHT AND EARLY
TUE AS A 35-40 KNOT LLJ WILL TRANSLATE NE ACROSS WI AND NRN LOWER
MI. MOST OF THE MODELS KEEP THE CONVECTION JUST TO OUR NW ONCE
AGAIN. THE OUTLIER IS THE TRUSTY EURO WHICH DEVELOPS PCPN OVER THE
NRN 2/3RDS OF THE CWFA AT THE LEADING EDGE OF THE WARM/MOIST SURGE.
THERE HAVE BEEN MANY TIMES THE EURO IS THE OUTLIER WITH A PCPN EVENT
LIKE THIS...AND HAS BEEN CORRECT. WE HAVE MAINTAINED SMALL CHCS OF
SHOWERS AND STORMS TONIGHT AND INTO TUE TO ACCOUNT FOR THAT. WE
SHOULD SEE SUNSHINE BREAK OUT TUE AFTERNOON AND MIX INTO H850 TEMPS
IN THE MID TEENS C. THIS WILL SUPPORT SOME POTENTIAL 80 DEGREE
READINGS TUE AFTERNOON.
ONCE THAT SURGE MOVES N AND E OF THE CWFA...WE SHOULD GENERALLY DRY
OUT FOR THE REMAINDER OF THE SHORT TERM THROUGH WED. THE FRONT WILL
LIKELY LINE UP ALONG THE NW MI COAST ALONG LAKE MICHIGAN. ALL OF THE
PCPN WILL BE ON THE COOL SIDE OF THE FRONT WITH THE WARMER AIR
OVERRIDING THE FRONT. H850 TEMPS REMAIN UP IN THE MID TEENS C...SO
80 DEGREES LOOKS ATTAINABLE ONCE AGAIN DURING THE DAY ON WED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 AM EDT MON APR 29 2013
LONG RANGE MODELS CONTINUE TO HAVE VERY POOR RUN TO RUN CONSISTENCY
WITH THE BLOCKING PATTERN ACROSS THE EASTERN CONUS THIS WEEK. HAVE
BEEN FORCED TO INCLUDE LOW CHANCE OR SLIGHT POPS ALMOST ALL PERIODS
ALTHOUGH IT IS POSSIBLE THAT MOST PERIODS WILL REMAIN DRY.
00Z GFS AND EURO SHOW THE BEST CHANCE FOR RAIN WILL BE ACROSS THE
WESTERN FORECAST AREA THURSDAY INTO FRIDAY AS THE UPPER TROUGH
APPROACHES. THEN IT STALLS AS THE SOUTHERN END OF THE TROUGH CUTS
OFF SPINS SOMEWHERE OVER THE PLAINS.
A NEW WRINKLE WITH THE 00Z EURO IS THAT THE UPPER LOW LIFTS NORTH
AND MISSES THE GREAT LAKES AS UPPER TROUGHING MOVES INTO WESTERN
CANADA. THIS IS A DEPARTURE FROM MOST OF THE PAST RUNS...SO WILL NOT
GIVE IT MUCH WEIGHT FOR NOW. WILL GO MORE WITH THE GFS IDEA OF
BRINGING THE UPPER LOW IN BY SUNDAY...ALTHOUGH THIS HAS TRENDED
SLOWER AND COULD BE DELAYED UNTIL MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 748 AM EDT MON APR 29 2013
SOME PATCHY IFR FOG EARLY THIS MORNING WILL LIFT WITH VFR
CONDITIONS EXPECTED TODAY. SOUTH WINDS WILL BE AROUND 10 KNOTS.
SHOWERS AND SCATTERED THUNDERSTORMS ARE POSSIBLE LATER TONIGHT BUT
COVERAGE SHOULD BE LOW AND SO WERE LEFT OUT OF THE FORECAST FOR
NOW.
&&
.MARINE...
ISSUED AT 344 AM EDT MON APR 29 2013
WE ARE GOING TO ISSUE A SMALL CRAFT ADVISORY FOR THE NEARSHORE
WATERS WITH THIS FCST PACKAGE. WINDS WILL INCREASE TONIGHT AS THE
BETTER PRESSURE GRADIENT MOVES IN ACROSS THE AREA. THIS WILL REMAIN
IN PLACE GENERALLY UNTIL THE MORNING HOURS ON WED BEFORE IT SHIFTS
WEST OF THE AREA WITH THE FRONT.
&&
.FIRE WEATHER...
ISSUED AT 344 AM EDT MON APR 29 2013
A SLIGHTLY ELEVATED FIRE DANGER WILL EXIST OVER THE NEXT FEW DAYS AS
TEMPS WARM UP QUITE A BIT AND WE STILL HAVE A WAYS TO GO BEFORE
GREENUP OCCURS EVERYWHERE. WINDS WILL PICK UP A BIT...ESPECIALLY ON
TUE WHEN THE BETTER GRADIENT WILL BE OVERHEAD. FORTUNATELY...RH
VALUES ARE NOT EXPECTED TO GET SIGNIFICANTLY LOW. WE HAVE NEAR 50
DEGREE DEW POINTS ALREADY ACROSS THE AREA. A SRLY FLOW WILL HELP
KEEP DEW POINTS UP...ALTHOUGH THEY COULD DROP A FEW DEGREES DURING
THE AFTERNOON HOURS DUE TO MIXING. WE ARE EXPECTING MIN RH VALUES IN
THE 35 TO 45 PCT RANGE IN GENERAL FOR THE NEXT FEW DAYS.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT MON APR 29 2013
NO ADDITIONAL HYDROLOGY PROBLEMS EXPECTED ON TOP OF THE RESIDUAL
FLOOD WARNINGS AND ADVISORIES THAT ARE ALREADY OUT FOR SOME OF THE
RIVER POINTS. WE HAVE A CHANCE OF SEEING RAIN ON AT LEAST A COUPLE
OF OCCASIONS THIS WEEK. THE RAINS DO NOT LOOK TO BE HEAVY NOR
WIDESPREAD OVER OUR AREA. AMOUNTS SHOULD GENERALLY STAY BELOW 0.50
INCHES. ADDITIONAL RAIN SHOWERS WILL REMAIN POSSIBLE INTO NEXT
WEEK...WITH NO SIGNIFICANT RAINS EXPECTED AT THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 11 AM EDT
WEDNESDAY FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...OSTUNO
AVIATION...OSTUNO
FIRE WEATHER...NJJ
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
754 AM EDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT MON APR 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG 160 KNOT 250-300 MB
JET MOVING INTO THE PAC NW AND A MAINLY ZONAL FLOW DOWNSTREAM TO THE
NRN GREAT LAKES. AT THE SFC...A COLD FRONT EXTENDED FROM LOW PRES
OVER HUDSON BAY TO NEAR JAMES BAY AND THROUGH WRN UPPER MI INTO NW
IA. THE COMBINATION OF LOW LEVEL CONV NEAR THE FRONT AND A WEAK
SHRTWV INTO UPPER SUPPORTED AN AREA OF LIGHT SHOWERS ACROSS CNTRL
UPPER MI INTO ERN LAKE SUPERIOR. HIGH PRES FROM THE NRN PLAINS WAS
BUILDING TOWARD THE REGION BRINGING IN DRIER AIR ALONG WITH CLEARING
SKIES FROM NRN MN INTO WRN LAKE SUPERIOR AND WRN UPPER MI. WITH SOME
LEFTOVER LOW LEVEL MOISTURE FROM THE LIGHT RAIN AND MELTING SNOW
ALONG WITH RADIATIONAL COOLING...SOME FOG HAD DEVELOPED FROM IWD TO
CMX.
RADAR/SATELLITE TRENDS SUGGEST THAT THE AREA OF SHOWERS WILL MOVE
THROUGH THE REST OF THE ERN HALF OF THE CWA THIS MORNING AS THE
FRONT GRADUALLY WEAKENS OVER SRN UPPER MI. AS ANOTHER WEAK SHORTWAVE
OVER SOUTH DAKOTA MOVES TOWARD THE AREA LATE THIS AFTERNOON AND
EVENING...MODELS SUGGEST THAT PCPN WILL AGAIN DEVELOP AND LIFT TO
THE NORTHEAST. HOWEVER...THERE REMAINS SOME UNCERTAINTY WITH THE
TIMING OF THE PCPN DEVELOPMENT AND MOVEMENT AND ON HOW FAR TO THE
NORTH INTO CNTRL UPPER MI THE PCPN WILL EXPAND. SO...ONLY CHANCE
POPS WERE INCLUDED FOR NOW. INSTABILITY TO SUPPORT TSRA...PER MDLS
MUCAPE...IS EXPECTED TO REMAIN SOUTH OF THE AREA.
FARTHER TO THE NORTHWEST...DRY CONDITIONS WILL PREVAIL WITH A
SUNSHINE AND WARM CONDITIONS. WITH 850 MB TEMPS AROUND 8C...TEMPS
SHOULD AGAIN CLIMB INTO THE MID 60S. READINGS IN THE UPPER 50S AND
LOWER 60S AND EXPECTED WHERE GREATER CLOUD COVER PREVAILS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 518 AM EDT MON APR 29 2013
EXTENDED FORECAST BECOMES MORE COMPLEX WITH ADDITION OF
THUNDERSTORMS /SOME ON THE STRONGER SIDE/ TUE AND TUE NIGHT AND SNOW
WED NIGHT INTO FRI. WILL FOCUS ON THESE TWO TIME FRAMES DUE TO MORE
BENIGN WEATHER AT THESE TIMES AND HELPING MANAGE EXTRA WORKLOAD ON
MORE IMPACTFUL HYDROLOGIC ISSUES.
FOR TUE...STARTING 12Z TUE THERE IS WILL BE AN UPPER SHORTWAVE
TROUGH OVER ND...WITH THE ASSOCIATED 995MB SFC LOW OVER NRN MN. THE
SYSTEM WILL MOVE TO HUDSON BAY BY 12Z WED WHILE DRAGGING A COLD
FRONT ACROSS THE CWA. THE COLD FRONT WILL ENCOUNTER VERY WARM LOW
LEVEL TEMPS AS 850MB TEMPS WILL BE AROUND 15C RESULTING IN HIGHS IN
THE 60S AND 70S. THUNDERSTORMS CERTAINLY APPEAR POSSIBLE...WITH EVEN
UP TO AROUND 1000 J/KG OF MUCAPE OVER THE REGION. THANKFULLY...SHEAR
WILL BE WEAK WHICH WILL FURTHER LIMIT SEVERE POTENTIAL. THERE COULD
BE SOME STRONGER STORMS...BUT NO SEVERE WEATHER IS EXPECTED AT THIS
TIME. DO SEE THE FRONT MOVE INTO WRN UPPER MI AROUND 00Z
WED...MOVING TO THE ERN U.P. BY 12Z WED. COULD ALSO SEE SOME HEAVY
RAINFALL...WHICH WILL NOT HELP HYDROLOGIC SITUATION DUE TO SNOWMELT
OVER THE CWA.
AFTER THE SYSTEM MOVES AWAY FROM THE AREA...THE CWA WILL BE SQUEEZED
BETWEEN A DEEPENING UPPER TROUGH JUST W OF THE CWA AND A
STRENGTHENING UPPER RIDGE JUST E OF THE CWA. AN 850MB TROUGH WILL BE
ANCHORED OVER THE CWA. ALL THIS WILL HAPPEN WED AND THU...BEFORE THE
UPPER TROUGH CLOSES OFF OVER MY BY FRI AS THE UPPER RIDGE GETS CUT
OFF AND MOVES INTO THE CWA FROM THE E. FGEN PRECIP ON THE NW SIDE OF
THE 850MB TROUGH WILL LEAD TO THE POSSIBILITY OF SIGNIFICANT PRECIP
OVER THE CENTRAL/WESTERN CWA WED NIGHT INTO FRI...MUCH OF WHICH MAY
BE SNOW OVER THE FARTHER W ZONES. THERE REMAINS A GOOD AMOUNT OF
UNCERTAINTY...BUT HEADLINE WORTHY SNOW DOES LOOK POSSIBLE OVER THE
WRN CWA. WITH AFOREMENTIONED HYDRO CONCERNS...WILL HAVE TO CONTINUE
TO CLOSELY LOOK AT PTYPE/AMOUNTS AS THE WEEK PROGRESSES.
WARMER TEMPS LOOK TO RETURN ON FRI AS 850MB TEMPS INCREASE UP TO
9C...WARMEST E. FOR NEXT WEEKEND...UNCERTAINTY INCREASES
SIGNIFICANTLY...SO WILL JUST USE A CONSENSUS OF MODEL GUIDANCE FOR
THIS PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 754 AM EDT MON APR 29 2013
THE ARRIVAL OF HIGH PRES AND DRIER AIR IN THE PRESENCE OF DAYTIME
HEATING LATER THIS MORNING SHOULD RESULT IN VFR CONDITIONS AT ALL 3
SITES TODAY. MORE CLOUDS IN ADVANCE OF A RETURNING WARM FRONT WILL
ARRIVE S TO N LATER TODAY. THERE MAY BE SOME -SHRA AND MVFR
CONDITIONS AT SAW BY LATE THIS EVENING CLOSER TO THE RETURNING FRONT
AND MOISTURE WITH AN UPSLOPE SE FLOW. COOLING THIS EVENING AND
OVERNIGHT ALONG WITH THE INFLUX OF LOW LEVEL MOISTURE IS LIKELY TO
BRING FOG TO SAW/CMX WITH LIFR OR VLIFR CONDITIONS OVERNIGHT.
DOWNSLOPE FLOW AT IWD SHOULD LIMIT FOG DEVELOPMENT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT MON APR 29 2013
WINDS SHOULD STAY BELOW 25KT THROUGH THE PERIOD WITH NO GALES
EXPECTED. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&
.HYDROLOGY...
ISSUED AT 518 AM EDT MON APR 29 2013
YESTERDAY SAW TEMPS IN THE 60S AND 70S...FOLLOWED BY LOWS LAST NIGHT
IN THE 40S...WHICH HAS KEPT THE MELTING GOING ACROSS THE CWA. SNOW
DEPTHS HAVE FALLEN 15-20 INCHES IN THE LAST WEEK. THE MOST SNOW
REMAINS ON THE GROUND ACROSS NORTHERN UPPER MICHIGAN IN THE INLAND
AND HIGHER TERRAIN AREAS. STILL HAVE TO MELT ANOTHER 12-20 INCHES OF
SNOW IN SOME OF THESE AREAS. TROUGH MOVING THROUGH TONIGHT INTO
TODAY IS DROPPING GENERALLY AROUND 0.25 INCHES OF RAIN...BUT IN SOME
CASES UP TO .5 INCHES HAS FALLEN. ADDITIONAL RAIN WITH POSSIBLE
THUNDERSTORMS MAY OCCUR TUESDAY INTO TUESDAY NIGHT AS A COLD FRONT
WORKS ACROSS UPPER MICHIGAN. HIGHER MOISTURE OVER THE AREA MAY RESULT
IN HEAVY DOWNPOURS WITH ANY THUNDERSTORMS. MUCH COOLER TEMPERATURES
EXPECTED FOR REST OF WEEK BEHIND THE FRONT. ADDITIONAL CHANCES OF
RAIN AND EVEN SNOW WILL ALSO CONTINUE ACROSS UPPER MICHIGAN FOR THE
REST OF THE WEEK. SO...EVEN THOUGH TEMPERATURES WILL BE COOLER THIS
MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION THAT MAY OCCUR.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...THE ONTONAGON
RIVER AT EWEN AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL REMAIN THE BIGGEST CONFIDENCE
REDUCERS IN RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS
WHERE MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS
YET...ALTHOUGH READINGS WILL BE GATHERED FROM THE PESHEKEE RIVER AND
LAKE MICHIGAMME THIS MORNING BY NWS PERSONNEL WHICH SHOULD HELP GET
A BETTER IDEA OF MELTING CONDITIONS INTO THE BASIN. AT OTHER
LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED TO MORE
ACCURATELY GET A HANDLE OF MELT RATES FOR THE RIVER MODELS. NWS
SURVEY OF THE PESHEKEE RIVER ON SATURDAY REVEALED THICK ICE COVERING
MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4 RIVER GAUGING
LOCATION /AUTOMATED GAUGE DISCONTINUED BUT OBS ARE BEING TAKEN USING
A WIRE WEIGHT GAUGE AT THE LOCATION/ AND THICK ICE COVER ON MOST OF
LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS MAY CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES THROUGH MONDAY. MAIN STEM
RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT OF AREAL
FLOOD PROBLEMS WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. HAVE RECEIVED SOME SPORADIC REPORTS OF AREAL TYPE
FLOODING...BUT NOT ENOUGH SIGNIFICANT REPORTS FOR HAZARD ISSUANCE.
FOR COMPLETE DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE
LATEST RIVER FLOOD WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
636 AM CDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM CDT MON APR 29 2013
A PACIFIC COLD FRONT...CURRENTLY ENTERING WRN WY...WILL MOVE THROUGH
THE FCST AREA TONIGHT. LOW PRESSURE AHEAD OF THE FRONT WILL DEEPEN
ACROSS WRN SD AND SEND ANOTHER SURGE OF WARM DRY AIR THROUGH THE
FCST AREA. THE RAP WHICH HAS BEEN VERIFYING WELL SUGGESTS 80S FOR
HIGHS TODAY MOST AREAS. DEW POINTS WILL FALL INTO THE 20S ONCE
AGAIN. THE CLEARING AREA ACROSS WY AND SD SHOULD MOVE EAST ACROSS
THE FCST AREA AND PROVIDE SUNNY SKIES TODAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 353 AM CDT MON APR 29 2013
FORECAST CONCERN FOR THE EXTENDED PERIOD REVOLVES AROUND
PRECIPITATION CHANCES MID-WEEK...SOME OF WHICH MAY FALL AS SNOW.
THE UNSETTLED PATTERN REMAINS THROUGH THE ENTIRE FORECAST
PERIOD...AS MODEL CONSENSUS SUGGESTS A STAGNATE PATTERN DEVELOPS
LATE WEEK...WITH A CUTOFF LOW AIMLESSLY MEANDERING THROUGH THE LOWER
MISSOURI VALLEY.
MODELS HAVE COME INTO GOOD AGREEMENT REGARDING THE TIMING OF THE
COLD FRONT...WHICH IS PROGGED TO PASS THROUGH THE FORECAST AREA
EARLY TUESDAY...THUS THE ATMOSPHERE WILL BE CHARACTERIZED BY POST
FRONTAL CONDITIONS...WITH STRONG CAA FILTERING SOUTH ACROSS THE CWA
THROUGH THE DAY ON TUESDAY. HIGHS WILL BE SOME 20-25 DEGREES
FAHRENHEIT COOLER THAN OBSERVED TODAY...WITH MOST READINGS REMAINING
THE 50S. ALSO OF NOTE...SHOWERS WILL BE ON THE INCREASE THROUGH THE
AFTERNOON AS A MID LEVEL SHORTWAVE WORKS IN CONJUNCTION WITH THE
RIGHT REAR ENTRANCE OF A STRONG UPPER JET MAX...PRECIPITATION WILL
SPREAD WEST TO EAST THROUGH THE AFTERNOON...AND SHOULD BECOME
FOCUSED ALONG AN AREA OF MIDLEVEL FRONTOGENETIC FORCING THAT APPEARS
TO BISECT THE CWA FROM SOUTHWEST TO NORTHEAST DURING THE AFTERNOON
HOURS /MAINLY THROUGH THE CENTRAL SANDHILLS/. PRECIPITATION CHANCES
BECOME MORE WIDESPREAD INTO THE EVENING HOURS AND OVERNIGHT AS DPVA
SPREADS EAST FROM ROCKIES ONTO THE NORTHERN HIGH PLAINS. ANALYSIS
OF THE 300-305K ISENTROPIC LAYER INDICATES SEVERAL HOURS /00-06Z
WEDNESDAY/ OF STRONG UPGLIDE TARGETING WESTERN AND NORTH CENTRAL
NEBRASKA...THEREAFTER DOWNGLIDE STARTS TO TAKE CONTROL WITH
CONDENSATION PRESSURE DEFICITS RAPIDLY RISING ABOVE 10MB...THUS CUT
BACK QPF AMOUNTS SOME ON WEDNESDAY WITH MOST LOCATIONS EXPECTING
LESS THAN A HALF OF AN INCH TOTAL QPF. ALSO TRIMMED POPS BACK INTO
THE LOW END CHANCE/SLIGHT CHANCE CATEGORY WEDNESDAY AFTERNOON AS
THE UPPER SUPPORT TRANSITIONS EAST WITH THE BEST UPGLIDE.
PROBLEMATIC TO THE FORECAST IS THE POTENTIAL FOR SNOW OR A RAIN/SNOW
MIX TUESDAY NIGHT AFTER MIDNIGHT THROUGH THE MORNING HOURS ON
WEDNESDAY...AS THE OPERATIONAL MODELS GENERATE AS MUCH AS FOUR TO
SIX INCHES ACROSS THE SANDHILLS...HOWEVER PROXIMITY SOUNDINGS
INDICATE FACTOR THAT MAY LIMIT OVERALL SNOW PRODUCTION AS THE
DENDRITIC LAYER IS CENTERED NEAR 500MB OVER SOUTHERN AND EASTERN
PORTIONS OF THE CWA /600-700 MB ACROSS THE NORTH AND
NORTHWEST/...AND GIVEN A RATHER SHORT PERIOD OF DEEP TROPOSPHERIC
MOISTURE...SNOW PRODUCTION MAY BE LIMITED. ANOTHER FACTOR AGAINST
ACCUMULATING SNOW IS THE RECENT WARM SPELL...WHICH HAS ALLOWED
GROUND TEMPERATURES TO CLIMB INTO THE 40S. SO FOR NOW WILL GO WITH
LIMITED TO NIL ACCUMULATIONS WITH THE IDEA THAT SUBSEQUENT
FORECASTS WILL HAVE A BETTER IDEA OF WHERE AND IF SNOW
ACCUMULATES.
A STRONG /~1040MB/ SURFACE HIGH WILL BUILD ACROSS THE HIGH PLAINS
EARLY ON THURSDAY AND REMAIN THROUGH FRIDAY MORNING...FROST AND/OR
FREEZE CONDITIONS WILL BE POSSIBLE.
THE UPPER PATTERN BECOMES STALE BY LATE WEEK WITH A CUTOFF LOW
FORMING AND REMAINING SOMEWHERE IN THE VICINITY OF THE LOWER
MISSOURI VALLEY. TEMPERATURES HEADING INTO THE WEEKEND SHOULD
SLOWLY MODERATE ACROSS OUR WESTERN ZONES...WITH THE
EAST...INFLUENCED BY THE UPPER LOW...REMAINING RATHER COOL. THE
LONGER RANGE SOLUTIONS CONTINUE TO INDICATE WRAP AROUND QPF POSSIBLY
AS FAR WEST AS HIGHWAY 61 THROUGH THE WEEKEND. CONFIDENCE IN STALE
PATTERNS USUALLY IS FAIRLY LOW...THUS WON/T MAKE ANY WHOLESALE
CHANGES TO THE EXTENDED PROCEDURE FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 633 AM CDT MON APR 29 2013
VFR IS EXPECTED ALL AREAS THROUGH 06Z TONIGHT. THEREAFTER...A COLD
FRONT WILL ENTER NRN NEB...POSSIBLY PRODUCING A BAND OF MVFR CIGS
ALONG THE FRONT. GIVEN THE VERY DRY CONDITIONS ONGOING...THE
PROBABILITY OF THIS OCCURRING IS LOW.
&&
.FIRE WEATHER...
ISSUED AT 353 AM CDT MON APR 29 2013
LOW PRESSURE DEEPENS ACROSS WRN SD THIS AFTERNOON TO AROUND 990 MB.
THIS SEND ANOTHER SURGE OF WEST/SOUTHWEST WINDS AND VERY DRY AIR
THROUGH THE PANHANDLE AND INTO NCNTL NEB. WINDS SHOULD INCREASE TO
15 TO 25 MPH WITH RH BETWEEN 10 AND 15 PERCENT. GREEN UP IS UNDERWAY
SO FUEL STATUS IS QUESTIONABLE FOR CRITICAL FIRE DANGER ACROSS NWRN
NEB. NO RED FLAG WARNING WILL BE ISSUED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...CDC
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
652 AM CDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 354 AM CDT MON APR 29 2013
A VERY ACTIVE WEATHER PATTERN IN STORE FOR THE REGION THIS WEEK.
FIRST OFF...WILL BE WATCHING A WEAK COLD FRONT SAGGING SOUTH ACROSS
THE AREA TODAY. TWO SHORTWAVE TROUGHS ARE EXPECTED TO MOVE ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY TODAY AND INTERACT WITH THE FRONT
AS IT EDGES SOUTH...SPARKING OFF SHOWERS AND THUNDERSTORMS. THE
FIRST LEADING SHORTWAVE WAS RACING EAST ACROSS SOUTH DAKOTA EARLY
THIS MORNING WHILE THE SECOND WAVE WAS MOVING EAST ACROSS WYOMING.
THE LEADING TROUGH WILL MOVE ACROSS THE REGION THIS MORNING
KEEPING SHOWERS AND ISOLATED THUNDERSTORMS GOING THROUGH MUCH OF
THE MORNING HOURS. THE TRAILING WAVE WILL ARRIVE EARLY THIS
AFTERNOON...PUSHING ACROSS NORTHERN IOWA THEN INTO SOUTHERN
WISCONSIN BY LATE AFTERNOON INTO THE EARLY EVENING HOURS. THE
FRONT IS EXPECTED TO STALL OUT ACROSS NORTHERN IOWA THROUGH
SOUTHERN WISCONSIN LATE THIS AFTERNOON AND THEN START TO LIFT
NORTH AND ACT AS A WARM FRONT LATE THIS AFTERNOON INTO THIS
EVENING AS VIGOROUS TROUGH DIVES INTO THE NORTHWEST CONUS. AN
INTERESTING ENVIRONMENT SETS UP OVER NORTHEAST IOWA AND FAR
SOUTHWEST WISCONSIN LATE THIS AFTERNOON AS THIS WARM FRONT TAKES
SHAPE. KBLR NAM FORECAST SOUNDINGS SHOW RATHER IMPRESSIVE SHEAR
PROFILES...WITH 0-6 KM BULK SHEAR OF 45 TO 50 KTS...AND 0-1 KM
BULK SHEAR OF 20 TO 25 KTS. CURVATURE ALSO NOTED IN THE HODOGRAPH
FROM THE SURFACE TO 2 KM. THE RAP IS ALSO SHOWING SIMILAR SHEAR
PROFILES. THE NAM IS INDICATING NEARLY 1500 J/KG 0-3KM MUCAPE
VALUES ACROSS THESE AREAS THIS AFTERNOON...BUT THIS IS LIKELY WAY
OVERDONE GIVEN THE NAM IS SHOWING DEWPOINTS CLIMBING TO 60 DEGREES
THIS AFTERNOON. 60 DEGREE DEWPOINTS ARE DISPLACED WAY TO THE
SOUTH...OVER NORTHERN TEXAS. THINKING THE HIGHEST DEWPOINTS THAT
WOULD BE ADVECTED INTO THE AREA WOULD BE IN MID 50S. THE GFS SEEMS
TO BE A LITTLE MORE REALISTIC WITH DEWPOINTS CREEPING INTO THE MID
50S. THINKING THE HIGHEST MUCAPE VALUES WILL BE IN THE 500 TO 800
J/KG RANGE. SOME SURFACE BASED CAPE IS POSSIBLE NEAR THE WARM
FRONT. THE MAJOR LIMITING FACTOR FOR SEVERE THUNDERSTORM POTENTIAL
THIS AFTERNOON IS THE LACK OF MOISTURE/CAPE. THERE MAY BE A BRIEF
WINDOW FOR SEVERE THUNDERSTORMS OVER FAR SOUTHWEST WISCONSIN INTO
NORTHEAST IOWA. PLENTY OF SHEAR FOR SUPERCELLS. THINKING THE MAIN
THREATS WILL BE LARGE HAIL AND DAMAGING WINDS. IF A SURFACE BASED
STORM COULD DEVELOP ALONG THE FRONT...THERE COULD BE A VERY SHORT
WINDOW OF OPPORTUNITY FOR AN ISOLATED TORNADO...BUT IT APPEARS
UNLIKELY AT THIS TIME. WILL HAVE TO KEEP A VERY CLOSE WATCH ALONG
THE WARM FRONT THIS AFTERNOON TO SEE HOW SURFACE DEWPOINTS RESPOND
AS SOUTHERLY FLOW INCREASES INTO THE FRONT. HIGHS TODAY ARE
EXPECTED TO BE A LITTLE COOLER THAN YESTERDAY WITH THE CLOUDS AND
PRECIPITATION OVER THE AREA. PLAN ON HIGHS RANGING FROM THE MID TO
UPPER 60S.
THE WARM FRONT WILL LIFT NORTH ACROSS THE FORECAST AREA TONIGHT
THROUGH EARLY TUESDAY MORNING. 925 MB WARM AIR ADVECTION INCREASES
ACROSS THE FORECAST AREA IN THE WAKE OF THE WARM FRONT...IN THE WARM
SECTOR. DRY AIR ALOFT MOVES IN WITHIN THE WARM SECTOR AND LOOKS TO
EFFECTIVELY CAP THE ENVIRONMENT. HOWEVER...THE NAM IS SUGGESTING
THERE COULD BE ELEVATED CAPE. LIFTING FROM 900 MB YIELDS AROUND 700
J/KG CAPE. DECIDED TO KEEP THE SHOWER AND THUNDERSTORM CHANCES GOING
TONIGHT MAINLY AFTER 06Z. LOWS TONIGHT WILL BE ON THE MILD
SIDE...ESPECIALLY IN THE WAKE OF THE WARM FRONT...WITH LOWS IN THE
MID TO UPPER 50S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 354 AM CDT MON APR 29 2013
THE UPPER TROUGH WILL CONTINUE TO DIG INTO THE CENTRAL CONUS ON
TUESDAY. MEANWHILE...SURFACE LOW PRESSURE IS EXPECTED TO DEEPEN AND
LIFT NORTH ACROSS NORTHERN MINNESOTA AND EVENTUALLY INTO WESTERN
ONTARIO. A COLD FRONT LOOKS TO PUSH SOUTHEAST ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY THROUGH THE DAY ON TUESDAY...WITH SHOWERS
AND THUNDERSTORMS DEVELOPING ALONG THE FRONT MAINLY DURING THE
AFTERNOON HOURS. TEMPERATURES WILL WARM RATHER NICELY AHEAD OF THE
COLD FRONT...WITH HIGHS CLIMBING TO AROUND 80 DEGREES ACROSS
PORTIONS OF NORTHEAST IOWA THROUGH SOUTHWEST WISCONSIN. THE
NAM/GFS/GEM ARE IN FAIRLY DECENT AGREEMENT...SHOWING CONVECTION
DEVELOPING ALONG THE FRONT LATE TUESDAY AFTERNOON INTO TUESDAY
EVENING. THE NAM SEEMS WAY TO AGGRESSIVE WITH ITS DEWPOINTS TUESDAY
AFTERNOON SHOWING SURFACE DEWPOINTS CLIMBING INTO THE MID 60S. MID
TO UPPER 50S SEEM MORE REASONABLE AND THIS IS WHAT IS BEING
ADVERTISED BY THE GEM...WITH 0-3 MUCAPE VALUES AROUND 1500 J/KG. 0-6
KM SHEAR VALUES AROUND 40 KTS WOULD SUPPORT THE POTENTIAL FOR SEVERE
THUNDERSTORMS. PLAN ON SHOWERS AND STORMS ERUPTING ALONG THE FRONT
DURING THE AFTERNOON HOURS. SOME OF THE STORMS MAY BECOME SEVERE
WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. THE TROUGH
CONTINUES TO DIG TUESDAY NIGHT INTO WEDNESDAY WITH A DEFORMATION
ZONE SETTING UP ACROSS THE UPPER MIDWEST...STRETCHING FROM EASTERN
NEBRASKA NORTHEAST THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION
AND NORTH INTO CENTRAL ONTARIO. A VERY IMPRESSIVE FRONTOGENESIS ZONE
SETS UP ACROSS THE AREA TUESDAY NIGHT AND SITS RIGHT OVER THE
FORECAST AREA WEDNESDAY INTO THURSDAY. LOOKING AT FORECAST MODEL
CROSS SECTIONS RUNNING FROM EAST TO WEST ACROSS THE AREA...A VERY
IMPRESSIVE FRONTOGENESIS ZONE SETS UP OVER THE REGION AND EXTENDS
FROM 875 MB THROUGH 500 MB...WITH NEGATIVE EPV POSITIONED RIGHT OVER
THE FRONTOGENESIS ZONE. THIS ZONE STAYS OVER THE AREA ALL THE WAY
INTO THURSDAY. THIS WILL LEAD TO A PROLONGED PERIOD OF
PRECIPITATION OVER THE AREA WHICH COULD BE MODERATE TO HEAVY AT
TIMES. DRY AND COOL NORTHERLY FLOW INTO THE REGION THEN RAISES THE
QUESTION OF PRECIPITATION TYPE. DEPENDING ON WHICH MODEL SOLUTION
VERIFIES...IT APPEARS THAT THE PRECIPITATION SHOULD FALL AS RAIN
TUESDAY NIGHT AND THROUGH MOST OF THE DAY ON WEDNESDAY THEN SWITCH
OVER TO A RAIN SNOW MIX WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING. A RAIN SNOW MIX IS POSSIBLE AGAIN THURSDAY NIGHT...THEN
THE PRECIPITATION WILL SWITCH BACK OVER TO ALL RAIN DURING THE DAY
ON FRIDAY AS THE TROUGH CLOSES INTO AN UPPER LOW OVER MISSOURI AND
WARMER AIR FLOWS BACK TO THE NORTH. SNOW ACCUMULATIONS ARE
POSSIBLE LATE WEDNESDAY NIGHT AND AGAIN THURSDAY NIGHT. AT THIS
TIME IT APPEARS A SLUSHY 1-3 INCHES IS POSSIBLE MAINLY ON GRASS
SURFACES. WILL ALSO HAVE TO KEEP A CLOSE EYE ON PRECIPITATION
TYPE...ESPECIALLY THURSDAY NIGHT INTO FRIDAY MORNING AS THE WARM
LAYER SURGES BACK TO THE NORTH. A BRIEF PERIOD OF SLEET IS
POSSIBLE BEFORE TEMPERATURES NEAR THE SURFACE WARM ABOVE FREEZING.
MODEL SOLUTIONS START TO DIVERGE THIS WEEKEND WITH THE HANDLING OF
THE LOW AS IT CUTS OFF. THE GEM TAKES THE LOW INTO THE SOUTHERN
PLAINS...WHILE THE ECMWF LIFTS IT NORTHWEST THROUGH THE DAKOTAS.
THE GFS KEEPS IT STALLED OVER MISSOURI THEN FINALLY LIFTS IT NORTH
INTO THE GREAT LAKES LATE ON SUNDAY. AFTER A COOL PERIOD THURSDAY
AND FRIDAY...WHERE HIGHS WILL ONLY BE IN THE LOWER 40S...SLIGHTLY
WARMER TEMPERATURES ARE POSSIBLE THIS WEEKEND DESPITE CHANCES FOR
RAIN...WITH HIGHS IN THE LOWER TO MIDDLE 50S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 652 AM CDT MON APR 29 2013
APPEARS THE TAF SITES WILL CATCH A BREAK FROM SHRA AND ANY REDUCED
CIGS/VSBYS THIS MORNING WITH THE FORCING/INSTABILITY SHIFTING SOUTH
OF THE AREA. OVERNIGHT RAINS AT KRST PLUS LIGHT WINDS PRODUCING SOME
BR/FG ACROSS SOUTHEAST MN AND ADDED SOME BR MENTION TO KRST EARLY
THIS MORNING. AFTER THAT THOUGH...CONFIDENCE REMAINS ON THE LOW SIDE
FOR THE AFTERNOON AND TONIGHT AS FAR AS CONVECTION CHANCES AND
EVOLUTION AT THE TAF SITES. A STALLED/WEAKENING FRONTAL BOUNDARY
WILL REMAIN IN THE AREA...AND BE A POTENTIAL TRIGGER FOR MORE
SHRA/TSRA THIS AFTERNOON/EVENING. CONVECTION POTENTIAL IS GOING TO
DEPEND ON HOW MUCH LOWER LEVEL MOISTURE AND INSTABILITY CAN OR DOES
MOVE NORTHWARD INTO THE AREA TODAY. GIVEN INCONSISTENT MODEL SIGNALS
FOR THE MOISTURE INCREASE AND ABILITY OF THE STALLED/WEAKENING
BOUNDARY TO TRIGGER CONVECTION...ONLY INCLUDED A VCSH MENTION AT THE
TAF SITES IN THE 22-02Z TIME PERIOD FOR NOW.
BOUNDARY LIFTS NORTH AS A WARM FRONT TONIGHT...WITH THE INCREASING
LOWER LEVEL MOISTURE EXPECTED TO SPREAD NORTH ACROSS THE AREA. STILL
PLENTY OF POSSIBLE SCENARIOS FOR CONVECTION EVOLUTION TONIGHT INTO
TUE. WITH THE INCREASE OF MOISTURE AND MOISTURE CONVERGENCE LATE
TONIGHT...INCLUDED A VCSH MENTION AFTER 09Z FOR NOW UNTIL A MORE
CONSISTENT SIGNAL IS SEEN. ADDED A LATE NIGHT MVFR BR MENTION AT
KRST AS WELL DUE TO THE SOUTHEAST FLOW AND MOISTURE INCREASE.
&&
.HYDROLOGY...
ISSUED AT 354 AM CDT MON APR 29 2013
HEAVY RAINFALL IS POSSIBLE THIS WEEK AS A SYSTEM STALLS OUT
ACROSS THE REGION TOWARD MID WEEK. FORECAST GUIDANCE SUGGESTS
TOTAL RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE POSSIBLE BY THE END OF
THE WEEK. SOME OF THIS PRECIPITATION COULD FALL AS A SLEET/SNOW
MIX. IF THESE RAINFALL AMOUNTS ARE REALIZED...THERE WOULD BE AN
INCREASE IN RIVER LEVELS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RRS
HYDROLOGY....WETENKAMP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
511 PM CDT MON APR 29 2013
.DISCUSSION...
323 PM CDT
MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.
NEAR TERM...TONIGHT-WEDNESDAY
SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.
ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.
LONGER TERM...THURSDAY-MONDAY
MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* SHRA/TSRA POSSIBLE OVERNIGHT.
MDB
//DISCUSSION...UPDATED 22Z...
SHRA/TSRA THAT WERE MOVING ALONG THE IL/WI STATE LINE HAVE
DISSIPATED WITH A LITTLE LIGHT RAIN REMAINING NEAR UGN. FOCUS
SHIFTS TO EAST-CENTRAL/NORTHEAST IOWA WHERE NEW DEVELOPMENT IS
POSSIBLE THIS EVENING WHICH WOULD TRACK EASTWARD OVERNIGHT.
ADJUSTED TO TEMPO TSRA MENTION AT RFD AS AM UNABLE TO USE PROB30
IN THE FIRST 9 HRS. WITH POTENTIAL AROUND 40 PERCENT FELT TEMPO
BETTER REFLECTED THE SCENARIO THAN DROPPING MENTION ALTOGETHER.
WILL MAINTAIN PROB30 FOR NOW AT THE REMAINING SITES FOR NOW AND
WILL NEED TO RE-EVALUATE WITH 00Z TAF.
MDB
FROM 18Z...
A FRONT IS NEARLY STATIONARY FROM NORTHERN WISCONSIN THROUGH
CENTRAL IOWA. ONE AREA OF TSRA DEVELOPED NEAR THE FRONT IN IOWA THIS
MORNING AND HAS MOVED INTO WISCONSIN. THERE IS POTENTIAL FOR MORE
TSRA TO DEVELOP NEAR THE FRONT THIS AFTERNOON AS AN UPPER LEVEL
WAVE MOVES THROUGH THE AREA. ANY DEVELOPMENT SHOULD REMAIN TO THE
NORTHWEST OF THE TERMINALS...THOUGH IT COULD GET CLOSE TO RFD AT
SOME POINT. CONFIDENCE IS TOO LOW TO INCLUDE ANY TSRA IN THE RFD
TAF FOR THIS AFTERNOON. THEN THERE IS A SLIGHTLY BETTER CHANCE OF
TSRA AT ALL THE TERMINALS OVERNIGHT WITH ANOTHER WAVE MOVING
ACROSS THE AREA.
SOUTHERLY WINDS...GUSTY IN THE AFTERNOON...AND VFR-LEVEL CLOUDS
WILL CONTINUE AT THE TERMINALS AHEAD OF THE FRONT.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* LOW CONFIDENCE IN SHRA/TSRA AT THE TERMINALS...BETTER CHANCE IS
JUST TO THE NORTH. MEDIUM CONFIDENCE IN TIMING OF THE POTENTIAL.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR.
WEDNESDAY...CHC OF TSRA. MVFR POSSIBLE BY NIGHT.
THURSDAY...CHC OF TSRA. MVFR POSSIBLE.
FRIDAY THROUGH SUNDAY...CHC OF SHRA.
BMD
&&
.MARINE...
205 PM CDT
A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.
THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
324 PM CDT MON APR 29 2013
.DISCUSSION...
323 PM CDT
MAIN FORECAST CONCERNS ARE TRYING TO TIME PERIODS OF PRECIP
POTENTIAL THROUGH MID-WEEK...AND WARM TEMPS DURING THE SAME TIME
PERIOD. BEYOND MID-WEEK...CLOSED UPPER LOW LOOKS TO INFLUENCE LOCAL
WEATHER FOR SEVERAL DAYS WITH COOLER TEMPS AND PERSISTENT THREAT OF
SCATTERED SHRA/TSRA.
NEAR TERM...TONIGHT-WEDNESDAY
SMALL CLUSTER OF ISOLATED SHRA/TSRA CONTINUES TO PROPAGATE EAST
ALONG THE IL/WI BORDER THIS AFTERNOON...ON NOSE OF 25-30 KT LOW
LEVEL JET PER LOCAL VWP AND ASSOCIATED WARM/MOIST ADVECTION. HAS NOT
BEEN MUCH REDEVELOPMENT UPSTREAM OF THIS CLUSTER...THOUGH IT HAS
BEEN QUITE PERSISTENT IN MAINTAINING AT LEAST ONE FAIRLY STRONG TSRA
CORE FOR SEVERAL HOURS. EXPECT THIS WILL CONTINUE TO MOVE EAST
ACROSS BOONE/MCHENRY AND LAKE COUNTIES OVER THE NEXT COUPLE OF HOURS
AND MAY PRODUCE SOME ISOLATED NICKEL-QUARTER SIZED HAIL SOUTH OF THE
WI STATE LINE. LOOKING AT THE BIGGER PICTURE...GOES VAPOR IMAGERY
DEPICTS ONE MID-LEVEL SHORT WAVE MOVING ACROSS WI/NORTHERN GREAT
LAKES REGION THIS AFTERNOON...WITH ANOTHER UPSTREAM ACROSS KS/NEBR.
IT WOULD APPEAR THAT THERE WOULD BE A LULL IN PRECIP DEVELOPMENT
BETWEEN THESE TWO FORCING MECHANISMS THIS EVENING...WITH THE PLAINS
WAVE APPROACHING THE AREA LATE TONIGHT. HOWEVER...SEVERAL HIGH-RES
CONVECTION-ALLOWING MODELS INDICATE POTENTIAL REDEVELOPMENT OF
SHRA/TSRA ACROSS EASTERN IA INTO NORTHERN IL THIS EVENING...WHERE
WEAK LOW LEVEL JET AND MOIST/INSTABILITY AXIS LINGER. MID-AFTERNOON
VISIBLE SATELLITE IMAGERY DOES INDICATE SOME CU ATTEMPTING TO FORM
ACROSS SOUTHEAST IA WITHIN SFC MOIST AXIS...THOUGH IT IS NOT TOO
IMPRESSIVE AT THIS TIME. SPC RAP MESOANALYSIS DATA DOES DEPICT AN
AXIS OF 1000-2000 J/KG MLCAPE ACROSS SE IA...THOUGH ALSO INDICATES
SOME 75-100 J/KG OF CIN. BASED ON PRESENCE OF MOIST/UNSTABLE AXIS
AND HIGH-RES GUIDANCE TRENDS OF REDEVELOPMENT HAVE CHOSEN TO
MAINTAIN CHANCE POPS FOR SHRA/TSRA ACROSS MAINLY AREAS NORTH OF I-80
THROUGH TONIGHT...ESPECIALLY WEST THIS EVENING AND SPREADING FARTHER
EAST LATER TONIGHT. LACK OF STRONGER SHORT WAVE FORCING KEEPS
CONFIDENCE ON THE LOW SIDE THIS EVENING HOWEVER...WITH A LITTLE
HIGHER CONFIDENCE OVERNIGHT AS PLAINS SHORT WAVE APPROACHES AND
PASSES ACROSS THE AREA EARLY TUESDAY MORNING.
ON TUESDAY...ONCE MORNING SHORT WAVE PASSES IT APPEARS FORCING FOR
ORGANIZED PRECIP WILL BE LACKING. COLD FRONT TO OUR WEST IS NOT
EXPECTED TO MAKE PROGRESS EAST AS UPPER FLOW AMPLIFIES IN RESPONSE
TO STRONG MID/UPPER LEVEL JET MOVING INTO THE PAC NW. THIS
AMPLIFICATION INDUCES SURFACE LOW PRESSURE DEVELOPING AND LIFTING
NORTHEAST INTO ONTARIO. THIS ALLOWS STRONGER LOW LEVEL SOUTH FLOW
ACROSS IL/IN...WITH WARMER TEMPS. COMBINATION OF LOW LEVEL THERMAL
PROGS...850 MB DERIVED TEMP CLIMATOLOGY AND MOS NUMBERS SUGGEST
AFTERNOON HIGHS 80-85...PROVIDED MORNING CLOUD COVER MOVES OUT AS
EXPECTED. 850 MB TEMPS JUST A BIT LOWER WEDNESDAY AS UPPER TROUGH
CONTINUES TO AMPLIFY AND SURFACE COLD FRONTAL TROUGH DRIFTS EAST
INTO THE REGION...THOUGH ESPECIALLY EASTERN AREAS WILL LIKELY BE
BACK INTO THE LOWER 80S WHILE CLOUDS/PRECIP CHANCES INCREASE FROM
THE WEST. VARIOUS GUIDANCE SOLUTIONS SHOW SOME MINOR DIFFERENCES
WITH TIMING OF ARRIVAL OF THE FRONT AND ASSOCIATED PRECIP...THOUGH
ALL BASICALLY INCREASE POPS FAIRLY QUICKLY ACROSS THE CWA WEDNESDAY
NIGHT.
LONGER TERM...THURSDAY-MONDAY
MODELS CONTINUE THE TREND OF THE AMPLIFYING UPPER TROUGH BECOMING
CUT OFF FROM THE MAIN JET AND BECOMING A CLOSED LOW OVER THE
MID/LOWER MISSOURI VALLEY...THEN DRIFTING THIS CIRCULATION TO THE
EAST/NORTHEAST THROUGH THE REMAINDER OF THE FORECAST PERIOD. QUITE A
BIT OF SPREAD REMAINS IN ENSEMBLE SOLUTIONS...AS WELL AS THE
OPERATIONAL RUNS OF THE ECMWF/GFS. HAVE MADE LITTLE CHANGE TO GOING
FORECAST IN THE EXTENDED PERIOD AT THIS POINT BASED ON FAIRLY LOW
CONFIDENCE GIVEN MODEL SPREAD...AND THE NOTORIOUSLY PROBLEMATIC JOB
OF FORECASTING CUT-OFF CLOSED LOW DETAILS DAYS 4 AND BEYOND. OVERALL
HAVE MAINTAINED A FORECAST UTILIZING A BLEND OF GUIDANCE FOR TEMPS
AND POPS. WHILE COOLER...LOOKS LIKE 50S/60S FOR HIGHS AND 40S FOR
LOWS DEPENDING ON CLOUD COVER AND SHOWER COVERAGE. POPS ARE LIKELY
OVERDONE A BIT...AND WILL LIKELY BE ABLE TO BETTER DETAIL THEM IN
COMING DAYS AS THE PATH OF THE UPPER LOW BECOMES MORE CLEAR.
RATZER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SOUTHERLY WINDS...GUSTY THIS AFTERNOON AND AGAIN TUESDAY
AFTERNOON.
* POTENTIAL FOR SHRA/TSRA THIS AFTERNOON AND LATE TONIGHT.
PAW
//DISCUSSION...UPDATED 18Z...
A FRONT IS NEARLY STATIONARY FROM NORTHERN WISCONSIN THROUGH
CENTRAL IOWA. ONE AREA OF TSRA DEVELOPED NEAR THE FRONT IN IOWA THIS
MORNING AND HAS MOVED INTO WISCONSIN. THERE IS POTENTIAL FOR MORE
TSRA TO DEVELOP NEAR THE FRONT THIS AFTERNOON AS AN UPPER LEVEL
WAVE MOVES THROUGH THE AREA. ANY DEVELOPMENT SHOULD REMAIN TO THE
NORTHWEST OF THE TERMINALS...THOUGH IT COULD GET CLOSE TO RFD AT
SOME POINT. CONFIDENCE IS TOO LOW TO INCLUDE ANY TSRA IN THE RFD
TAF FOR THIS AFTERNOON. THEN THERE IS A SLIGHTLY BETTER CHANCE OF
TSRA AT ALL THE TERMINALS OVERNIGHT WITH ANOTHER WAVE MOVING
ACROSS THE AREA.
SOUTHERLY WINDS...GUSTY IN THE AFTERNOON...AND VFR-LEVEL CLOUDS
WILL CONTINUE AT THE TERMINALS AHEAD OF THE FRONT.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TREND.
* LOW CONFIDENCE IN POTENTIAL FOR SHRA/TSRA THIS AFTERNOON AND LATE
TONIGHT.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR.
WEDNESDAY...CHC OF TSRA. MVFR POSSIBLE BY NIGHT.
THURSDAY...CHC OF TSRA. MVFR POSSIBLE.
FRIDAY THROUGH SUNDAY...CHC OF SHRA.
BMD
&&
.MARINE...
205 PM CDT
A POTENT AREA OF LOW PRESSURE IS FORECAST MOVE EASTWARD ACROSS THE
DAKOTAS TONIGHT...AND THEN MOVE NORTHEASTWARD ACROSS ONTARIO ON
TUESDAY. STRONG PRESSURE FALLS AND A STRENGTHENING PRESSURE GRADIENT
SHOULD LEAD TO A PERIOD OF STRONGER SOUTHERLY WINDS ACROSS THE LAKE
ON TUESDAY. IT APPEARS WINDS WILL INCREASE TO AROUND 30 KT
LAKE-WIDE.
THIS LOW WILL EVENTUALLY BEGIN TO PUSH A COLD FRONT DOWN LAKE
MICHIGAN DURING THE DAY ON WEDNESDAY. HOWEVER...CONFIDENCE ON THE
TIMING OF THIS FRONT IS A BIT LOW AT THIS TIME..ESPECIALLY ALONG
THE SOUTHERN HALF OF LAKE MICHIGAN. IT APPEARS THE FRONT MAY BE
SLOWED BY THE DEVELOPMENT OF ANOTHER AREA OF LOW PRESSURE ACROSS THE
MID MISSISSIPPI VALLEY. THIS WILL ULTIMATELY AFFECT THE WIND
DIRECTIONS ON SOUTHERN LAKE MICHIGAN LATER THIS WEEK. NORTHERLY
WINDS OF 25 TO 30 KT LOOK TO SET UP FOR A PERIOD IN THE WAKE OF THIS
FRONTAL BOUNDARY ON THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
342 PM CDT MON APR 29 2013
.SHORT TERM.../TONIGHT /...
ISSUED AT 338 PM CDT MON APR 29 2013
MAIN CONCERN FOR THE OVERNIGHT PERIOD WILL BE THE TIMING AND
LOCATION OF ANY CONVECTION. INSTABILITY HAS BEEN ON THE INCREASE
THIS AFTERNOON WITH SBCAPES OF 1000 TO 2000 J/KG ACROSS MUCH OF THE
CWA...AND EVEN HIGHER VALUES AROUND THE MISSOURI BORDER. THE 850 TO
700 MB CAP LOOKS TO WEAKEN AFTER THE 23-00Z TIME FRAME AS A 925MB
MOISTURE PLUME OVER KANSAS AND MISSOURI WORKS NORTHWARD. EXPECTING
CONVECTIVE INITIATION IN THE VICINITY OF THE ASSOCIATED THETA-E
CONVERGENCE ZONE IN SOUTHWEST IOWA OR SOUTHEAST NEBRASKA...WITH THE
CONVECTION TRACKING EAST AND NORTH DURING THE OVERNIGHT. THIRTY TO
FORTY KNOTS OF 0-6 KM SHEAR AND A 40 TO 60 KT LLJ BUILDING IN FROM
THE SOUTHWEST AFTER 03Z WILL AID IN INTENSIFYING AND MAINTAINING ANY
STORMS THAT DO FORM THIS EVENING. BOTH ELEVATED AND SURFACE BASED
CONVECTION IS POSSIBLE WITH THE MAIN THREAT FROM THESE STORMS BEING
LARGE HAIL AND DAMAGING WIND GUSTS.
MANY HIGH RESOLUTION MODELS HAVE BEEN TRENDING THE CONVECTION
SLIGHTLY NORTH AND WEST TODAY. THIS HAS ALSO BEEN REFLECTED IN THE
UPDATED SPC CONVECTIVE DAY 1 SLIGHT RISK OUTLOOKS. IN
GENERAL...LEANED TOWARDS A COMBINATION OF THE EAST NMM AND ARW WRF
CORES AND THE 16Z HRRR FOR PLACEMENT OF THE HIGHEST POPS AND QPF
AMOUNTS. HEAVY RAINFALL IS POSSIBLE WITH SOME OF THESE STORMS OVER
CENTRAL IOWA WITH PWATS EXCEEDING ONE INCH AND LOW LEVEL MIXING
RATIOS AROUND 13 G/KG.
STATIONARY SURFACE BOUNDARY OVER WEST CENTRAL AND NORTH CENTRAL IOWA
WASHED OUT EARLY THIS AFTERNOON...ALLOWING WINDS TO VEER SOUTHWARD
AND TEMPERATURES TO RISE BACK INTO THE 70S. THESE SOUTHERLY WINDS
WILL INCREASE OVERNIGHT AS THE PRESSURE GRADIENT TIGHTENS IN RESPONSE
TO AN APPROACHING NORTHERN PLAINS COLD FRONT. COMBINED WITH DEW POINTS IN
THE UPPER 50S TO NEAR 60...EXPECT OVERNIGHT LOWS TO ONLY FALL OFF
INTO THE LOW 60S.
.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 338 PM CDT MON APR 29 2013
I EXPECT SOME ONGOING CONVECTION MAINLY ACROSS THE EAST IN THE
MORNING WITH A LULL LATE MORNING. ANOTHER COLD FRONT WILL STRETCH
ACROSS CENTRAL IOWA DURING THE DAY ON TUESDAY AND MAKE SLOW ESE
PROGRESS. FORECAST SOUNDINGS SHOW A PRETTY STOUT CAP IN PLACE BUT
IT QUICKLY ERODES DURING THE MID TO LATE AFTERNOON AND INTO THE
EVENING AND THIS IS WHEN I EXPECT THUNDERSTORMS TO BREAK OUT...AHEAD
OF THE BOUNDARY. LOOKING AT SHEAR...THERE IS SOME THAT EXISTS ALONG
THE BOUNDARY BUT THE BEST SHEAR IS FOUND BEHIND THE BOUNDARY. SOME
STORMS COULD PRODUCE LARGE HAIL AND DAMAGING WIND. DURING TUESDAY
EVENING ADDITIONAL STORMS COULD DEVELOP BEHIND THE FRONT AS WELL
WHERE THE BETTER SHEAR WILL EXIST AND THERE WILL STILL BE SOME
INSTABILITY.
ON WEDNESDAY THE UPPER TROUGH OUT TO THE WEST WILL DIG SOUTH ON THE
LEE SIDE OF THE ROCKIES CREATING QUITE THE TEMPERATURE GRADIENT
ACROSS IOWA. ACROSS THE NORTHWEST HALF TO TWO THIRDS OF THE STATE
HIGHS WILL ONLY BE IN THE 40S AND 50S WHILE ACROSS THE SOUTHEAST
TEMPERATURES WILL BE IN THE 60S TO 70S. THIS TROUGH WILL CONTINUE
TO DIG AS IT PLOWS EAST THROUGH THURSDAY. FORECAST SOUNDINGS ON
THURSDAY SHOW FALLING TEMPERATURES THROUGHOUT THE AFTERNOON HOURS.
IN FACT IT LOOKS LIKE HIGHS WILL LIKELY BE REACHED IN THE MORNING
AND THOSE READINGS WILL ONLY BE IN THE 40S. PRETTY DECENT MOISTURE
TRANSPORT WILL TAKE PLACE DURING THIS TIME AND PRECIPITATION WILL
YIELD SOME PRETTY HIGH QPF VALUES THROUGH THE REMAINDER OF THE
WEEK. FORECAST SOUNDINGS SHOW THAT WE WILL BE COLD ENOUGH FOR AT
MINIMUM A RAIN/SNOW MIX DURING THE DAY ON THURSDAY. IF YOU BELIEVE
THE NAM WE WILL BE COLD ENOUGH FOR ALL SNOW. I HAD A HARD TIME
BUYING INTO THAT SOLUTION COMPLETELY BECAUSE FOR THE PAST FEW DAYS
THE NAM HAD BEEN OVERDOING THE MOISTURE AND THE COOLING. THIS WILL
CERTAINLY BEAR WATCHING BUT I WOULD NOT BE SURPRISED TO SEE SNOW
THURSDAY AFTERNOON AND THURSDAY NIGHT.
BEYOND THIS PERIOD...THE MODELS CONTINUE TO POORLY HANDLE THE
EVOLUTION OF THE CLOSED LOW THAT DEVELOPS OUT OF THE TROUGH. THE
EURO LIFTS THIS CLOSED LOW INTO IOWA OVER THE WEEKEND THEN INTO THE
GREAT LAKES ON MONDAY WHILE THE GFS AND GEM TAKE THE LOW TO THE
SOUTH ACROSS THE SOUTHERN PLAINS. THIS SOLUTION WOULD DRAW DOWN
MUCH COLDER AIR ACROSS THE STATE FOR THE WEEKEND. I TRIED TO LEAN
COOLER BUT BY SUNDAY FORECAST SOUNDINGS SUPPORT HIGHS IN THE 50S. AT
THIS POINT I KEPT 40S NW TO 50S SE ON SATURDAY BUT WE COULD INDEED
SEE TEMPS SOME 5 TO 8 DEGREES COOLER THAT WHAT I HAVE GOING. WE
WILL NEED TO SEE HOW THAT CLOSED LOW EVOLVES AND SHIFTS ACROSS THE
AREA. BEFORE THAT HAPPENS THERE IS JUST TOO MUCH MODEL UNCERTAINTY
TO STATE A PREFERENCE.
&&
.AVIATION...29/18Z
ISSUED AT 1251 PM CDT MON APR 29 2013
WINDS OVER NORTHERN IOWA WILL VEER TO THE SOUTH THIS AFTERNOON AS
A FRONTAL BOUNDARY WEAKENS AND LIFTS NORTHWARD. OTHERWISE LOOK FOR
MOSTLY VFR CONDITIONS OVER THE REGION...WITH SOME MID TO HIGH MVFR
STRATOCU OVER NORTHEAST IOWA. NEXT SYSTEM APPROACHES FROM THE
SOUTH THE EVENING. PLACEMENT AND TIMING OF THE ASSOCIATED SHOWERS
AND THUNDERSTORMS REMAINS SOMEWHAT UNCERTAIN...BUT THE GENERAL
TREND WILL BE FOR THE STORMS TO LIFT FROM SOUTHWEST TO NORTHEAST
DURING THE OVERNIGHT HOURS...CLEARING THE REGION SHORTLY AFTER 12Z.
&&
.HYDROLOGY...
ISSUED AT 338 PM CDT MON APR 29 2013
HE MODERATE TO HEAVY RAINFALL EVENT FORECAST IN THE LONG TERM
PERIOD OF THE FORECAST MAY RESULT IN SIGNIFICANT WITHIN-BANK RISES
ALONG MANY STREAMS AND RIVERS. FLOODING IS ALSO
POSSIBLE...ESPECIALLY ALONG THE SMALLER STREAMS AND IN AREAS THAT
RECEIVE HEAVIER RAINFALL. AT THIS TIME IT IS DIFFICULT TO PINPOINT
SPECIFIC STREAMS OR RIVERS GIVEN THE UNCERTAINTY IN THE RAINFALL
FORECAST. THE FORECAST WILL HAVE TO BE MONITORED FOR POTENTIAL
IMPACTS ON AREA RIVERS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SKOW
LONG TERM...FAB
AVIATION...SKOW
HYDROLOGY...ZOGG
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
224 PM EDT MON APR 29 2013
.SYNOPSIS...
LOW PRESSURE LIFTS NORTHEAST ACROSS THE MID ATLANTIC TODAY AND OFF
THE COAST TONIGHT. LOW PRESSURE LINGERS OFF THE CAROLINA COAST
THROUGH MIDWEEK AS HIGH PRESSURE BUILDS OFF THE NEW ENGLAND COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT RADAR TRENDS SHOWING PRECIP CONTINUING TO MOVE E/NE THIS
MORNING...WITH AREAS WEST OF RIC BEGINNING TO SEE SOME BREAKS IN THE
PRECIP. HAVE UPDATED POPS TO SHOW THIS TREND...BUT HAVE KEPT 30-50
PERCENT CHANCE OF PRECIP IN THE WEST TO ACCOUNT FOR -SHRA
DEVELOPMENT THIS AFTERNOON. OTHERWISE FORECAST LOOKS ON TARGET.
PREVIOUS DISCUSSION...
THE LATEST RUC MAINTAINS THIS STRONG LIFT OVER THE LOCAL AREA
THROUGH 12Z BEFORE SHIFTING IT TOWARD THE EASTERN PORTION OF THE
AREA FROM 12-16Z AS THE JET CORE PULLS NE TOWARD LONG ISLAND AND
THE MID-LEVEL TROUGH AXIS INTRUDES FROM THE WEST. THIS SHOULD
ALLOW STEADY RAIN TO SLOWLY TAPER OFF W OF I-95 THROUGH THE
MORNING. THE MAIN AREA OF ASCENT THEN SHIFTS TO SE PORTIONS BY
AFTERNOON AS A SECONDARY SPEED MAX MOVES OVER CENTRAL VA. A FEW
RUMBLES OF THUNDER ARE POSSIBLE OVER SE PORTIONS GIVEN THAT THIS
FEATURE ARRIVES DURING THE AFTERNOON. HOWEVER...AMBIENT RAIN
COOLED STABLE CONDITIONS WILL LIMIT INSTABILITY (AND LIMIT THE
POTENTIAL OF DEEP CONVECTION) HENCE THUNDER WILL NOT BE INCLUDED
IN THE GRIDS. THE LATEST DATA SUGGESTS THAT QPF COULD REACH 1.5IN
AND POSSIBLY CLOSE TO 2.0IN FOR SOME LOCATIONS BY THIS AFTERNOON
ACROSS S-CENTRAL/SE VA/EASTERN SHORE/NE NC. THIS HAS FURTHER
SUPPORT FROM UPSTREAM OBS OVER CENTRAL NC WHERE AMOUNTS HAVE
REACHED 1.0-1.5IN AND RAIN CONTINUES.
THE MID-LEVEL TROUGH AXIS MOVES OFF THE COAST TONIGHT WITH THE
ASSOCIATED WIND FLOW BECOMING NW (ALBEIT WEAK). THIS SHOULD ALLOW
STEADY RAIN TO TAPER OFF TO SHOWERS THIS EVENING FOR EASTERN AREAS.
THERE IS AN ABUNDANT AMOUNT OF LINGERING LOW-LEVEL MOISTURE THAT
WILL NOT BE SCOURED OUT BY WEAK FLOW...SO WIDESPREAD STRATUS IS
EXPECTED TO DEVELOP. THIS COULD EVENTUALLY SETTLE TO THE SURFACE
RESULTING IN THE POTENTIAL FOR FOG.
CLOUD COVER AND RAIN WILL LIMIT HIGH TEMPERATURES TODAY...WITH
READINGS RANGING FROM THE LOW/MID 60S (UPPER 50S ALONG THE ATLANTIC
COAST) OVER THE EASTERN SHORE TO THE UPPER 60S/NEAR 70 S. LOWS
TONIGHT WILL BE MILD AND LARGELY BE IN THE MID 50S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
HIGH PRESSURE RE-EXERTS ITSELF OVER THE CANADIAN MARITIMES TUESDAY
AND WEDNESDAY AND NUDGES SW ALONG THE NEW ENGLAND COAST.
MEANWHILE...A COASTAL TROUGH LINGERS OFF THE CAROLINA COAST. THIS
WILL MAINTAIN ONSHORE FLOW AND PERSISTENT MOSTLY CLOUDY TO OVERCAST
CONDITIONS. THE LATEST GFS/NAM/ECMWF DRAW MOISTURE AROUND THE
NORTHERN PERIPHERY OF THE TROUGH LATE TUESDAY NIGHT INTO WEDNESDAY
AHEAD OF A BACKDOOR FRONT. HOWEVER...CONFIDENCE IS LOW REGARDING
RAIN POTENTIAL AT THIS TIME...SO WILL GO WITH NO HIGHER THAN A 40
POP. THUNDER POTENTIAL SHOULD REMAIN VERY LIMITED DUE TO ONSHORE
FLOW AND SSTS IN THE LOW/MID 50S. IF ANY THUNDER WERE TO OCCUR
(MAINLY TUE) IT WOULD BE OVER INTERIOR NE NC AND S-CENTRAL VA.
AS FOR TEMPERATURES...THE COOLER MAV GUIDANCE HAS BEEN FOLLOWED AS
MET NUMBERS APPEAR TOO WARM BASED ON EXPECTED CLOUD COVER. THIS
RESULTS IN HIGHS TUESDAY RANGING FROM THE LOW/MID 60S OVER THE
EASTERN SHORE...TO THE LOW 70S ALONG AND S OF THE VA/NC BORDER (AWAY
FROM THE COASTS). HIGHS WEDNESDAY SHOULD BE A FEW DEGREES COOLER
RANGING FROM THE LOW 60S OVER THE EASTERN SHORE (PERHAPS UPPER 50S
ALONG THE COAST) THE THE UPPER 60S S. LOW TEMPERATURES SHOULD REMAIN
IN THE 50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LONG TERM PERIOD WILL BE CHARACTERIZED BY A STAGNANT BLOCKING
PATTERN WITH AN UPR-LVL RIDGE STRETCHED ALONG THE ERN SEABOARD. AT
THE SFC...HI PRES WILL PERSIST OVER THE MID ATLANTIC OR JUST
OFFSHORE LEADING TO LGT ONSHORE FLOW AND GENLY DRY CONDS. ADJUSTED
ANY CHC POPS DOWN TO SLGT CHC WITH UPR-LVL CUTOFF LO REMAINING WELL
OFFSHORE. OVERALL...STILL FAVORING THE SLIGHTLY SLOWER ECMWF GUIDANCE
WRT THE DEVELOPING CUTOFF LO OVER THE CENTRAL CONUS AS MODELS TEND
TO BREAK DOWN BLOCKING PATTERNS TOO SOON/PROGRESS CUTOFF LOWS TOO
QUICKLY. KEPT POPS CAPPED AT 20-30% OVER THE WEEKEND DUE TO ISSUES
WITH PRECIP TIMING WITH THE APPROACHING LO. AS FOR TEMPS...HIGHS AVG
IN THE UPR 60S/LWR 70S WITH LO TEMPS IN THE UPR 40S/LWR 50S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WIDESPREAD STRATIFORM RAIN CONTINUES TO MOVE SLIDE NW ACROSS
LOWER EASTERN SHORE/NORTHERN NECK THIS AFTN, WITH SOLID IFR/MVFR
CONDS ACROSS AREA TERMINALS. CIGS HAVE BEGUN TO RECOVER AS
EXPECTED WITH LOW CLOUDS GRADUALLY SCOURING OUT WEST OF RIC.
CONDITIONS IMPROVE TO MVFR/VFR AT RIC BY 21-22Z, ONLY TO FALL
BACK INTO IFR SHORTLY AFTER SUNSET, WITH LIFR CONDS POSSIBLE AFTER
06Z/2A TNGT. OVER COASTAL TERMINALS, EXPECT CIGS TO REMAIN IN MVFR
RANGE THROUGH THIS EVENING, FALLING TO IFR (LCL LIFR) IN LOW
CLOUDS/FOG TONIGHT.
OUTLOOK...IFR CONDITIONS DO GRADUALLY IMPROVE LATE TUE MORN.
HOWEVER, PERSISTENT NE FLOW SHOULD RESULT IN OCCASIONAL RAIN
SHOWERS WITH LINGERING LOW CLOUDS THROUGH WED, ESPECIALLY AT
COASTAL TERMINALS.
&&
.MARINE...
LOW PRESSURE APPROACHES THE AREA FROM THE WEST TODAY...THEN WEAKENS
AS IT CROSSES THE WATERS TONIGHT. LIGHT SE FLOW OVER THE WATERS
EARLY THIS MORNING WILL INCREASE DURING THE DAY TODAY DUE TO AN
INCREASING PRESSURE GRADIENT...ALLOWING FOR WINDS OF 15-20 KNOTS
OVER THE WATERS WITH SOME GUSTS UP TO 25 KT ON THE OCEAN. THE
EASTERLY COMPONENT TO THE WINDS WILL ALLOW SEAS TO BUILD ON THE
OCEAN...REACHING 5-6 BY LATE MORNING. SCA`S REMAIN IN PLACE FOR ALL
THE COASTAL WATERS (MAINLY FOR SEAS) TODAY THRU TUESDAY NIGHT. SCA`S
FOR THE CHES BAY/CURRITUCK SOUND CONTINUE THRU 7 PM THIS EVENING
WHEN THE PRESSURE GRADIENT SHOULD RELAX AND WINDS SUBSIDE. SFC HIGH
PRESSURE REMAINS LOCKED IN PLACE OVER NEW ENGLAND THRU THE COMING
WEEK ALLOWING FOR PERSISTENT E-NE WINDS OVER THE LOCAL WATERS.
ALTHOUGH WINDS WILL LIKELY REMAIN SUB-SCA DURING THIS TIME...SEAS
WILL REMAIN AOA 5 FT SO SCA`S WILL LIKELY CONTINUE FOR THE ENTIRE
WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
ANZ630>634.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT WEDNESDAY FOR ANZ650-652-
654-656-658.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ/DAP
SHORT TERM...AJZ
LONG TERM...MAS
AVIATION...JDM/MAM
MARINE...JDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
233 PM EDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT MON APR 29 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG 160 KNOT 250-300 MB
JET MOVING INTO THE PAC NW AND A MAINLY ZONAL FLOW DOWNSTREAM TO THE
NRN GREAT LAKES. AT THE SFC...A COLD FRONT EXTENDED FROM LOW PRES
OVER HUDSON BAY TO NEAR JAMES BAY AND THROUGH WRN UPPER MI INTO NW
IA. THE COMBINATION OF LOW LEVEL CONV NEAR THE FRONT AND A WEAK
SHRTWV INTO UPPER SUPPORTED AN AREA OF LIGHT SHOWERS ACROSS CNTRL
UPPER MI INTO ERN LAKE SUPERIOR. HIGH PRES FROM THE NRN PLAINS WAS
BUILDING TOWARD THE REGION BRINGING IN DRIER AIR ALONG WITH CLEARING
SKIES FROM NRN MN INTO WRN LAKE SUPERIOR AND WRN UPPER MI. WITH SOME
LEFTOVER LOW LEVEL MOISTURE FROM THE LIGHT RAIN AND MELTING SNOW
ALONG WITH RADIATIONAL COOLING...SOME FOG HAD DEVELOPED FROM IWD TO
CMX.
RADAR/SATELLITE TRENDS SUGGEST THAT THE AREA OF SHOWERS WILL MOVE
THROUGH THE REST OF THE ERN HALF OF THE CWA THIS MORNING AS THE
FRONT GRADUALLY WEAKENS OVER SRN UPPER MI. AS ANOTHER WEAK SHORTWAVE
OVER SOUTH DAKOTA MOVES TOWARD THE AREA LATE THIS AFTERNOON AND
EVENING...MODELS SUGGEST THAT PCPN WILL AGAIN DEVELOP AND LIFT TO
THE NORTHEAST. HOWEVER...THERE REMAINS SOME UNCERTAINTY WITH THE
TIMING OF THE PCPN DEVELOPMENT AND MOVEMENT AND ON HOW FAR TO THE
NORTH INTO CNTRL UPPER MI THE PCPN WILL EXPAND. SO...ONLY CHANCE
POPS WERE INCLUDED FOR NOW. INSTABILITY TO SUPPORT TSRA...PER MDLS
MUCAPE...IS EXPECTED TO REMAIN SOUTH OF THE AREA.
FARTHER TO THE NORTHWEST...DRY CONDITIONS WILL PREVAIL WITH A
SUNSHINE AND WARM CONDITIONS. WITH 850 MB TEMPS AROUND 8C...TEMPS
SHOULD AGAIN CLIMB INTO THE MID 60S. READINGS IN THE UPPER 50S AND
LOWER 60S AND EXPECTED WHERE GREATER CLOUD COVER PREVAILS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 518 AM EDT MON APR 29 2013
EXTENDED FORECAST BECOMES MORE COMPLEX WITH ADDITION OF
THUNDERSTORMS /SOME ON THE STRONGER SIDE/ TUE AND TUE NIGHT AND SNOW
WED NIGHT INTO FRI. WILL FOCUS ON THESE TWO TIME FRAMES DUE TO MORE
BENIGN WEATHER AT THESE TIMES AND HELPING MANAGE EXTRA WORKLOAD ON
MORE IMPACTFUL HYDROLOGIC ISSUES.
FOR TUE...STARTING 12Z TUE THERE IS WILL BE AN UPPER SHORTWAVE
TROUGH OVER ND...WITH THE ASSOCIATED 995MB SFC LOW OVER NRN MN. THE
SYSTEM WILL MOVE TO HUDSON BAY BY 12Z WED WHILE DRAGGING A COLD
FRONT ACROSS THE CWA. THE COLD FRONT WILL ENCOUNTER VERY WARM LOW
LEVEL TEMPS AS 850MB TEMPS WILL BE AROUND 15C RESULTING IN HIGHS IN
THE 60S AND 70S. THUNDERSTORMS CERTAINLY APPEAR POSSIBLE...WITH EVEN
UP TO AROUND 1000 J/KG OF MUCAPE OVER THE REGION. THANKFULLY...SHEAR
WILL BE WEAK WHICH WILL FURTHER LIMIT SEVERE POTENTIAL. THERE COULD
BE SOME STRONGER STORMS...BUT NO SEVERE WEATHER IS EXPECTED AT THIS
TIME. DO SEE THE FRONT MOVE INTO WRN UPPER MI AROUND 00Z
WED...MOVING TO THE ERN U.P. BY 12Z WED. COULD ALSO SEE SOME HEAVY
RAINFALL...WHICH WILL NOT HELP HYDROLOGIC SITUATION DUE TO SNOWMELT
OVER THE CWA.
AFTER THE SYSTEM MOVES AWAY FROM THE AREA...THE CWA WILL BE SQUEEZED
BETWEEN A DEEPENING UPPER TROUGH JUST W OF THE CWA AND A
STRENGTHENING UPPER RIDGE JUST E OF THE CWA. AN 850MB TROUGH WILL BE
ANCHORED OVER THE CWA. ALL THIS WILL HAPPEN WED AND THU...BEFORE THE
UPPER TROUGH CLOSES OFF OVER MY BY FRI AS THE UPPER RIDGE GETS CUT
OFF AND MOVES INTO THE CWA FROM THE E. FGEN PRECIP ON THE NW SIDE OF
THE 850MB TROUGH WILL LEAD TO THE POSSIBILITY OF SIGNIFICANT PRECIP
OVER THE CENTRAL/WESTERN CWA WED NIGHT INTO FRI...MUCH OF WHICH MAY
BE SNOW OVER THE FARTHER W ZONES. THERE REMAINS A GOOD AMOUNT OF
UNCERTAINTY...BUT HEADLINE WORTHY SNOW DOES LOOK POSSIBLE OVER THE
WRN CWA. WITH AFOREMENTIONED HYDRO CONCERNS...WILL HAVE TO CONTINUE
TO CLOSELY LOOK AT PTYPE/AMOUNTS AS THE WEEK PROGRESSES.
WARMER TEMPS LOOK TO RETURN ON FRI AS 850MB TEMPS INCREASE UP TO
9C...WARMEST E. FOR NEXT WEEKEND...UNCERTAINTY INCREASES
SIGNIFICANTLY...SO WILL JUST USE A CONSENSUS OF MODEL GUIDANCE FOR
THIS PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 231 PM EDT MON APR 29 2013
VFR CEILINGS AND VIS WILL LIKELY FALL THIS EVENING UNDER FOG...GIVEN
HIGH LEVELS OF LOW LEVEL MOISTURE AND INCREASED SOUTHERLY FLOW. LOOK
FOR FOG TO SLOWLY WEAKEN DURING THE DAY TUESDAY AS STRONGER
SOUTHERLY WINDS TAKE HOLD...WITH GUSTS OF 20-25KTS FROM LATE MORNING
ON. THE STRONGEST WINDS WILL BE LIKELY AT IWD AND SAW THROUGH THE
DAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT MON APR 29 2013
WINDS SHOULD STAY BELOW 25KT THROUGH THE PERIOD WITH NO GALES
EXPECTED. NO STRONG SYSTEMS WILL BE COMING CLOSE TO THE AREA...SO NO
STRONG PRESSURE GRADIENTS ARE EXPECTED.
&&
.HYDROLOGY...
ISSUED AT 518 AM EDT MON APR 29 2013
YESTERDAY SAW TEMPS IN THE 60S AND 70S...FOLLOWED BY LOWS LAST NIGHT
IN THE 40S...WHICH HAS KEPT THE MELTING GOING ACROSS THE CWA. SNOW
DEPTHS HAVE FALLEN 15-20 INCHES IN THE LAST WEEK. THE MOST SNOW
REMAINS ON THE GROUND ACROSS NORTHERN UPPER MICHIGAN IN THE INLAND
AND HIGHER TERRAIN AREAS. STILL HAVE TO MELT ANOTHER 12-20 INCHES OF
SNOW IN SOME OF THESE AREAS. TROUGH MOVING THROUGH TONIGHT INTO
TODAY IS DROPPING GENERALLY AROUND 0.25 INCHES OF RAIN...BUT IN SOME
CASES UP TO .5 INCHES HAS FALLEN. ADDITIONAL RAIN WITH POSSIBLE
THUNDERSTORMS MAY OCCUR TUESDAY INTO TUESDAY NIGHT AS A COLD FRONT
WORKS ACROSS UPPER MICHIGAN. HIGHER MOISTURE OVER THE AREA MAY RESULT
IN HEAVY DOWNPOURS WITH ANY THUNDERSTORMS. MUCH COOLER TEMPERATURES
EXPECTED FOR REST OF WEEK BEHIND THE FRONT. ADDITIONAL CHANCES OF
RAIN AND EVEN SNOW WILL ALSO CONTINUE ACROSS UPPER MICHIGAN FOR THE
REST OF THE WEEK. SO...EVEN THOUGH TEMPERATURES WILL BE COOLER THIS
MAY BE OFFSET BY THE ADDITIONAL PRECIPITATION THAT MAY OCCUR.
RIVERS OF PARTICULAR CONCERN DUE TO MELTING WILL BE THE TRAP ROCK
RIVER...THE STURGEON RIVER OF BARAGA/HOUGHTON COUNTIES...THE
PESHEKEE RIVER...THE PAINT RIVER NEAR CRYSTAL FALLS...THE ONTONAGON
RIVER AT EWEN AND EVENTUALLY THE MICHIGAMME RIVER NEAR REPUBLIC AND
WITCH LAKE. MELTING SCENARIOS STILL REMAIN THE BIGGEST CONFIDENCE
REDUCERS IN RIVER FORECASTS FOR THE PESHEKEE AND MICHIGAMME BASINS
WHERE MOST OF THE MELTING HAS NOT HIT ANY OBSERVED RIVER POINTS
YET...ALTHOUGH READINGS WILL BE GATHERED FROM THE PESHEKEE RIVER AND
LAKE MICHIGAMME THIS MORNING BY NWS PERSONNEL WHICH SHOULD HELP GET
A BETTER IDEA OF MELTING CONDITIONS INTO THE BASIN. AT OTHER
LOCATIONS...SUFFICIENT RUNOFF FROM MELTING HAS BEEN OBSERVED TO MORE
ACCURATELY GET A HANDLE OF MELT RATES FOR THE RIVER MODELS. NWS
SURVEY OF THE PESHEKEE RIVER ON SATURDAY REVEALED THICK ICE COVERING
MOST OF THE RIVER NEAR AND DOWNSTREAM OF THE CHPM4 RIVER GAUGING
LOCATION /AUTOMATED GAUGE DISCONTINUED BUT OBS ARE BEING TAKEN USING
A WIRE WEIGHT GAUGE AT THE LOCATION/ AND THICK ICE COVER ON MOST OF
LAKE MICHIGAMME WHICH THE PESHEKEE DRAINS INTO. ICE JAMS MAY CAUSE
SIGNIFICANT PROBLEMS AS THE RIVER RISES THROUGH MONDAY. MAIN STEM
RIVERS ARE NOT THE ONLY HAZARD...AS THERE IS ALSO A THREAT OF AREAL
FLOOD PROBLEMS WITH SMALLER CREEKS/STREAMS AND STANDING WATER ON
ROADS. HAVE RECEIVED SOME SPORADIC REPORTS OF AREAL TYPE
FLOODING...BUT NOT ENOUGH SIGNIFICANT REPORTS FOR HAZARD ISSUANCE.
FOR COMPLETE DETAILS...SEE THE HYDROLOGIC OUTLOOK /ESF/ AND THE
LATEST RIVER FLOOD WATCHES...WARNINGS AND ADVISORIES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...KF
MARINE...JLB
HYDROLOGY...TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
139 PM EDT MON APR 29 2013
.SYNOPSIS...
ISSUED AT 344 AM EDT MON APR 29 2013
AREAS OF FOG WILL BE FOUND EARLY THIS MORNING...ESPECIALLY ACROSS
AREAS NEAR AND SOUTH OF I-69. ONCE THE FOG DISSIPATES...MOST AREAS
SHOULD WARM UP NICELY TO AROUND 70 WITH A DECENT AMOUNT OF SUNSHINE.
THERE WILL BE A CHANCE OF SHOWERS UP NORTH THIS AFTERNOON.
A CHANCE OF SHOWERS AND STORMS WILL EXIST TONIGHT AND INTO TUESDAY
AS A WAVE OF LOW PRESSURE AND A SURGE OF WARMER AND MORE MOIST AIR
MOVES TOWARD THE AREA.
A FRONT EXPECTED TO NEARLY STALL OUT TO OUR WEST TUESDAY AND
WEDNESDAY WILL TRY TO LEAN INTO THE AREA ON THURSDAY AND INCREASE
THE CHANCE FOR SHOWERS AND STORMS. MUCH OF THE AREA COULD SEE THEIR
FIRST 80 DEGREE TEMPERATURE OF THIS SPRING ON TUESDAY AND/OR
WEDNESDAY.
&&
.UPDATE...
ISSUED AT 1202 PM EDT MON APR 29 2013
SHORTWAVE TROUGH IS PUSHING FROM MINNESOTA INTO WISCONSIN AT
MIDDAY WITH A SURFACE COLD FRONT LOCATED AHEAD OF IT STRETCHING
FROM WISCONSIN SOUTHWEST INTO IOWA. A BAND OF SHOWERS AND A FEW
EMBEDDED THUNDERSTORMS WERE LOCATED NEAR THE FRONT.
HI-RES WRF MODELS (NSSL AND SPC) AND THE HRRR KEEP THE BULK OF THE
PRECIPITATION TO THE NORTH AND WEST OF THE FORECAST AREA THIS
AFTERNOON. SOME SCATTERED SHOWER ACTIVITY IS POSSIBLE ACROSS ABOUT
THE NORTHERN THIRD OF THE FORECAST AREA AND HAVE MAINTAINED POPS
IN THE FORECAST UP THERE. THROUGH THE AFTERNOON...THE BEST
MOISTURE RETURN AND LIFT SHOULD BE WEST AND NORTH OF THE FORECAST
AREA. THE UPSTREAM SURFACE COLD FRONT ACTUALLY WASHES OUT WITH
TIME OVER ABOUT THE NEXT 18 HOURS AS NEW MID LEVEL ENERGY TAKES
OVER FROM THE WEST.
THE SHOWER AND POSSIBLY SOME THUNDERSTORM ACTIVITY DOES TRY TO
SPILL INTO THE CWA THIS EVENING AND TONIGHT. IT APPEARS THE
NORTHERN CWA MAY SEE PRECIPITATION THIS EVENING...SPREADING INTO
WESTERN PORTIONS OF THE FORECAST OVERNIGHT.
HIGH TEMPERATURES WILL MAKE A RUN INTO THE LOWER TO MIDDLE 70S AT
MOST LOCATIONS WITH COOLER READINGS NEAR LAKE MICHIGAN.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 344 AM EDT MON APR 29 2013
FORECAST CONCERNS WITH THE SHORT TERM INCLUDE FOG ISSUES THIS
MORNING AND PCPN TRENDS THROUGH THE PERIOD.
WE HAVE ISSUED A DENSE FOG ADVISORY FOR THE SE CORNER OF THE CWFA
FOR THIS MORNING. OBS AT KJXN...KTEW...KRMY...AND EVEN AT KLAN ARE
ALL AT OR HAVE BEEN AT 1/4SM EARLY THIS MORNING. THESE LOCATIONS
HAVE SEEN THE WORST CONDITIONS AS A RESULT OF THE BETTER RAINFALL
THAT OCCURRED ON SUNDAY. THE WORST VISIBILITIES SEEM TO ALIGN VERY
WELL WITH THE PLACES THAT SAW THE MOST RAIN PER THE KGRR STORM TOTAL
PCPN PRODUCT. WE HAVE KALAMAZOO COUNTY AND EATON COUNTY IN THE
ADVISORY EVEN THOUGH NO OBS OFFICIALLY SUPPORT FOG YET. DUE TO THE
RAINFALL PLACEMENT ON SUN...WE THINK THERE IS A GOOD CHANCE
LOCATIONS IN THESE COUNTIES ARE SEEING ENOUGH FOG TO JUSTIFY THE
ADVISORY THERE.
AS FAR AS PCPN TRENDS ARE CONCERNED...WE HAVE GENERALLY TRENDED THE
CHCS LOWER JUST A LITTLE THROUGH WED AS IT SEEMS LIKE THE FRONT WILL
GET HELD UP A LITTLE FURTHER WEST THAN PREVIOUSLY INDICATED. WE
BELIEVE THIS IS THE CASE SINCE THE MAIN TROUGH THAT FORMS THE UPPER
LOW DIGS A LITTLE FURTHER SOUTH AND WEST...HELPING TO BUILD THE
RIDGE CLOSER TO MI.
WE WILL SEE THE INITIAL FRONT NOW MAKING ITS WAY PAST KMSP AND INTO
WI. THIS FRONT IS EXPECTED TO STALL OUT SOON AS IT ALIGNS WITH THE
MID LEVEL FLOW. THE CONVECTION WITH IT SHOULD STAY CLOSE TO IT...AND
CLOUD SNEAK INTO THE NW CORNER OF THE CWFA LATER TODAY. WE BELIEVE
THAT MOST OF IT SHOULD REMAIN NW OF THE CWFA. THE FRONT WILL
GRADUALLY WASH OUT TONIGHT.
WE WILL SEE A SURGE OF WARM AND MOIST AIR ALOFT TONIGHT AND EARLY
TUE AS A 35-40 KNOT LLJ WILL TRANSLATE NE ACROSS WI AND NRN LOWER
MI. MOST OF THE MODELS KEEP THE CONVECTION JUST TO OUR NW ONCE
AGAIN. THE OUTLIER IS THE TRUSTY EURO WHICH DEVELOPS PCPN OVER THE
NRN 2/3RDS OF THE CWFA AT THE LEADING EDGE OF THE WARM/MOIST SURGE.
THERE HAVE BEEN MANY TIMES THE EURO IS THE OUTLIER WITH A PCPN EVENT
LIKE THIS...AND HAS BEEN CORRECT. WE HAVE MAINTAINED SMALL CHCS OF
SHOWERS AND STORMS TONIGHT AND INTO TUE TO ACCOUNT FOR THAT. WE
SHOULD SEE SUNSHINE BREAK OUT TUE AFTERNOON AND MIX INTO H850 TEMPS
IN THE MID TEENS C. THIS WILL SUPPORT SOME POTENTIAL 80 DEGREE
READINGS TUE AFTERNOON.
ONCE THAT SURGE MOVES N AND E OF THE CWFA...WE SHOULD GENERALLY DRY
OUT FOR THE REMAINDER OF THE SHORT TERM THROUGH WED. THE FRONT WILL
LIKELY LINE UP ALONG THE NW MI COAST ALONG LAKE MICHIGAN. ALL OF THE
PCPN WILL BE ON THE COOL SIDE OF THE FRONT WITH THE WARMER AIR
OVERRIDING THE FRONT. H850 TEMPS REMAIN UP IN THE MID TEENS C...SO
80 DEGREES LOOKS ATTAINABLE ONCE AGAIN DURING THE DAY ON WED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 344 AM EDT MON APR 29 2013
LONG RANGE MODELS CONTINUE TO HAVE VERY POOR RUN TO RUN CONSISTENCY
WITH THE BLOCKING PATTERN ACROSS THE EASTERN CONUS THIS WEEK. HAVE
BEEN FORCED TO INCLUDE LOW CHANCE OR SLIGHT POPS ALMOST ALL PERIODS
ALTHOUGH IT IS POSSIBLE THAT MOST PERIODS WILL REMAIN DRY.
00Z GFS AND EURO SHOW THE BEST CHANCE FOR RAIN WILL BE ACROSS THE
WESTERN FORECAST AREA THURSDAY INTO FRIDAY AS THE UPPER TROUGH
APPROACHES. THEN IT STALLS AS THE SOUTHERN END OF THE TROUGH CUTS
OFF SPINS SOMEWHERE OVER THE PLAINS.
A NEW WRINKLE WITH THE 00Z EURO IS THAT THE UPPER LOW LIFTS NORTH
AND MISSES THE GREAT LAKES AS UPPER TROUGHING MOVES INTO WESTERN
CANADA. THIS IS A DEPARTURE FROM MOST OF THE PAST RUNS...SO WILL NOT
GIVE IT MUCH WEIGHT FOR NOW. WILL GO MORE WITH THE GFS IDEA OF
BRINGING THE UPPER LOW IN BY SUNDAY...ALTHOUGH THIS HAS TRENDED
SLOWER AND COULD BE DELAYED UNTIL MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 139 PM EDT MON APR 29 2013
ADDED THE CHANCE FOR AN ISOLATED THUNDERSTORM AT THE INLAND TAF
SITES FOR THIS EVENING. AN UPPER LEVEL DISTURBANCE WILL CROSS THE
REGION IN THIS TIME FRAME ALONG WITH BUILDING INSTABILITY.
THE SOUTHERN FLOW WILL INCREASE AROUND SUNRISE TUESDAY...REACHING
NEAR 20 KTS TOWARD MID DAY.
&&
.MARINE...
ISSUED AT 344 AM EDT MON APR 29 2013
WE ARE GOING TO ISSUE A SMALL CRAFT ADVISORY FOR THE NEARSHORE
WATERS WITH THIS FCST PACKAGE. WINDS WILL INCREASE TONIGHT AS THE
BETTER PRESSURE GRADIENT MOVES IN ACROSS THE AREA. THIS WILL REMAIN
IN PLACE GENERALLY UNTIL THE MORNING HOURS ON WED BEFORE IT SHIFTS
WEST OF THE AREA WITH THE FRONT.
&&
.FIRE WEATHER...
ISSUED AT 344 AM EDT MON APR 29 2013
A SLIGHTLY ELEVATED FIRE DANGER WILL EXIST OVER THE NEXT FEW DAYS AS
TEMPS WARM UP QUITE A BIT AND WE STILL HAVE A WAYS TO GO BEFORE
GREEN UP OCCURS EVERYWHERE. WINDS WILL PICK UP A BIT...ESPECIALLY ON
TUE WHEN THE BETTER GRADIENT WILL BE OVERHEAD. FORTUNATELY...RH
VALUES ARE NOT EXPECTED TO GET SIGNIFICANTLY LOW. WE HAVE NEAR 50
DEGREE DEW POINTS ALREADY ACROSS THE AREA. A SRLY FLOW WILL HELP
KEEP DEW POINTS UP...ALTHOUGH THEY COULD DROP A FEW DEGREES DURING
THE AFTERNOON HOURS DUE TO MIXING. WE ARE EXPECTING MIN RH VALUES IN
THE 35 TO 45 PCT RANGE IN GENERAL FOR THE NEXT FEW DAYS.
&&
.HYDROLOGY...
ISSUED AT 344 AM EDT MON APR 29 2013
NO ADDITIONAL HYDROLOGY PROBLEMS EXPECTED ON TOP OF THE RESIDUAL
FLOOD WARNINGS AND ADVISORIES THAT ARE ALREADY OUT FOR SOME OF THE
RIVER POINTS. WE HAVE A CHANCE OF SEEING RAIN ON AT LEAST A COUPLE
OF OCCASIONS THIS WEEK. THE RAINS DO NOT LOOK TO BE HEAVY NOR
WIDESPREAD OVER OUR AREA. AMOUNTS SHOULD GENERALLY STAY BELOW 0.50
INCHES. ADDITIONAL RAIN SHOWERS WILL REMAIN POSSIBLE INTO NEXT
WEEK...WITH NO SIGNIFICANT RAINS EXPECTED AT THIS TIME.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 11 AM EDT
WEDNESDAY FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...OSTUNO
AVIATION...JK
FIRE WEATHER...NJJ
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
259 PM CDT MON APR 29 2013
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 256 PM CDT MON APR 29 2013
PRIMARY WEATHER CONCERN FOR TONIGHT IS THE POSSIBILITY OF CONVECTION
ACROSS NORTHERN MISSOURI AND WEST CENTRAL ILLINOIS. RUC CONTINUES
TO FORECAST COPIOUS AMOUNTS OF CAPE SOUTH OF A Q-STATIONARY FRONT
EXTENDING THROUGH NORTHEAST KANSAS INTO SOUTHEAST NEBRASKA AND
WESTERN IOWA LATE THIS AFTERNOON. GREATEST VALUES EXCEED 4000 J/KG
ACROSS PARTS OF WESTERN AND CENTRAL MISSOURI. HOWEVER...RUC ALSO
APPEARS TO BE 3 TO 5 DEGREES TOO MOIST ON DEWPOINT FORECASTS LATER
THIS AFTERNOON INTO THE EVENING WHICH WOULD DEFINITELY ACCOUNT FOR
THE GIHEMOUS CAPE VALUES. THAT BEING SAID...THERE IS SOME
AGITATED CU OVER SOUTH CENTRAL MISSOURI AND ONE LONE THUNDERSTORM
OVER NORTHERN ARKANSAS...SO THERE`S OBVIOUSLY SOME INSTABILITY OUT
THERE. CURRENT THINKING IS THAT THE ISOLATED CONVECTION OVER SOUTH
CENTRAL MISSOURI WON`T MAKE IT TO OUR AREA...AND THAT CONVECTION
WILL FIRE CLOSER TO THE BAROCLINIC ZONE IN NEBRASKA LATE THIS
AFTERNOON/EARLY EVENING AND RIDE UP ACROSS IOWA. COULD SEE THE TAIL
END OF ANY CONVECTIVE COMPLEX THAT FORMS AFFECT NORTHERN PORTIONS OF
THE CWFA SO HAVE KEPT LOW CHANCE POPS UP THERE. OTHERWISE...SHOULD
BE MILD AND QUIET NIGHT.
CARNEY
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 256 PM CDT MON APR 29 2013
TUESDAY THROUGH THURSDAY...CONFIDENCE MEDIUM
WELL ABOVE NORMAL TEMPERATURES ARE EXPECTED TUESDAY AND WEDNESDAY
AHEAD OF THE DIGGING TROF AND COLD FRONT. CAN`T ARGUE MUCH WITH MOS
GUIDANCE WITH HIGHS IN THE LOWER TO MIDDLE 80S AND LOWS IN THE 60S.
MODEL GUIDANCE IN GOOD AGREEMENT THAT COLD FRONT WILL WAIT UNTIL
WEDNESDAY NIGHT AND THURSDAY MORNING TO START MOVING ACROSS THE CWA.
PRECIPITATION CHANCES TO INCREASE FROM THE WEST...BUT BELIEVE A
LARGE PART OF THE CWA WILL REMAIN DRY THROUGH THURSDAY MORNING.
THIS WILL CHANGE THURSDAY AFTERNOON. THE MAIN BAND OF RAIN WILL EDGE
INTO CENTRAL AND NORTHEAST MISSOURI...WHILE CONVECTION FIRES ON THE
FRONT ITSELF ALONG AND EAST OF THE MISSISSIPPI RIVER. I AM SURE
SOMEONE IN THE MIDDLE OF THESE TWO AREAS OF PRECIPITATION MAY REMAIN
DRY...BUT IT IS TOO FAR OUT TO GET TOO CUTE WITH POP GRADIENTS.
SHOULD BE QUITE A TEMPERATURE CONTRAST ACROSS THE CWA ON THURSDAY
WITH STEADY OR SLOWLY FALLING TEMPERATURES IN THE 40S IN THE WESTERN
CWA...TO THE LOW/MIDDLE 70S IN SOUTH CENTRAL ILLINOIS.
FRIDAY THROUGH MONDAY...CONFIDENCE LOW
MODELS ARE STILL HAVING SOME DIFFICULTY IN HOW THEY HANDLE THE TRACK
OF THE CLOSED OFF LOW LATE THIS WEEK AND WEEKEND. PREFER TO KEEP
FORECAST TREND THE SAME...ESSENTIALLY FOLLOWING HPC GUIDANCE AND 12Z
ECWMF...WITH THE CLOSED OFF LOW DEVELOPING TO OUR WEST AND SPINNING
NORTHEAST ACROSS THE MIDWEST TOWARD THE GREAT LAKES THIS WEEKEND.
MARCHED THE MAIN BAND OF RAIN EAST THURSDAY NIGHT AND FRIDAY WITH
LIKELY POPS AND THEN CONTINUED LOW CHANCE POPS FOR RAIN SHOWERS
THROUGH MONDAY AS AREA EXPECTED TO REMAIN AT LEAST IN THE
VICINITY OF THE COLD CORE SYSTEM. FORECAST RAINFALL AMOUNTS WITH
THIS SOLUTION WOULD BE ON THE ORDER OF 1 TO 1.5 INCHES FOR THE
EVENT.
TEMPERATURES STILL ON TRACK TO FALL BACK BELOW NORMAL FRIDAY AND
SATURDAY...BUT SLOWLY WARM SUNDAY AND MONDAY AS INFLUENCE OF THE
SYSTEM WAINS BY THE BEGINING OF NEXT WEEK.
NOTE...THE 12Z GFS AND GEM CAME IN QUITE A BIT FURTHER TO THE
SOUTHWEST AND MUCH SLOWER WITH THE SYSTEM...WHICH WOULD RESULT IN A
PROLONGED PERIOD OF RAIN AS THE FRONT AND TROPICAL FETCH PARK ITSELF
ACROSS THE MISSISSIPPI RIVER VALLEY FOR THE ENTIRE WEEKEND. THIS
SOLUTION WOULD YIELD WIDESPREAD RAINFALL AMOUNTS IN EXCESS OF 2
INCHES...WITH SOME LOCALS OVER 4 INCHES.
CVKING
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1216 PM CDT MON APR 29 2013
VFR FLIGHT CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH TUESDAY
MORNING. THE ONLY POSSIBLE EXCEPTION WILL BE IN NORTHEAST MISSOURI
AND WEST CENTRAL ILLINOIS WHERE A PERIOD OF THUNDERSTORMS WILL BE
POSSIBLE THIS EVENING. LOW LEVEL WIND SHEAR IS LIKELY OVER CENTRAL
AND NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS TONIGHT...THE
WIND SHEAR POTENTIAL WILL DECREASE FURTHER EAST ACROSS EAST
CENTRAL MISSOURI AND SOUTHWEST ILLINOIS.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS ARE EXPECTED TO PREVAIL AT LAMBERT THROUGH
TUESDAY. THERE`S STILL A CHANCE THAT THUNDERSTORMS WILL DEVELOP
OVER PARTS OF NORTHERN MISSOURI THIS EVENING. THIS MAY AFFECT SOME
OF THE NORTHERN/NORTHWESTERN ARRIVAL GATES...BUT NO DIRECT IMPACTS
TO THE TERMINAL ARE EXPECTED.
CARNEY
&&
.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS 62 85 63 85 / 10 5 5 10
QUINCY 60 83 61 80 / 30 10 5 10
COLUMBIA 60 84 60 79 / 10 5 5 10
JEFFERSON CITY 61 84 60 81 / 10 5 5 10
SALEM 59 82 61 82 / 10 5 5 10
FARMINGTON 58 82 59 82 / 10 5 5 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
104 PM CDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM CDT MON APR 29 2013
A PACIFIC COLD FRONT...CURRENTLY ENTERING WRN WY...WILL MOVE THROUGH
THE FCST AREA TONIGHT. LOW PRESSURE AHEAD OF THE FRONT WILL DEEPEN
ACROSS WRN SD AND SEND ANOTHER SURGE OF WARM DRY AIR THROUGH THE
FCST AREA. THE RAP WHICH HAS BEEN VERIFYING WELL SUGGESTS 80S FOR
HIGHS TODAY MOST AREAS. DEW POINTS WILL FALL INTO THE 20S ONCE
AGAIN. THE CLEARING AREA ACROSS WY AND SD SHOULD MOVE EAST ACROSS
THE FCST AREA AND PROVIDE SUNNY SKIES TODAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 353 AM CDT MON APR 29 2013
FORECAST CONCERN FOR THE EXTENDED PERIOD REVOLVES AROUND
PRECIPITATION CHANCES MID-WEEK...SOME OF WHICH MAY FALL AS SNOW.
THE UNSETTLED PATTERN REMAINS THROUGH THE ENTIRE FORECAST
PERIOD...AS MODEL CONSENSUS SUGGESTS A STAGNATE PATTERN DEVELOPS
LATE WEEK...WITH A CUTOFF LOW AIMLESSLY MEANDERING THROUGH THE LOWER
MISSOURI VALLEY.
MODELS HAVE COME INTO GOOD AGREEMENT REGARDING THE TIMING OF THE
COLD FRONT...WHICH IS PROGGED TO PASS THROUGH THE FORECAST AREA
EARLY TUESDAY...THUS THE ATMOSPHERE WILL BE CHARACTERIZED BY POST
FRONTAL CONDITIONS...WITH STRONG CAA FILTERING SOUTH ACROSS THE CWA
THROUGH THE DAY ON TUESDAY. HIGHS WILL BE SOME 20-25 DEGREES
FAHRENHEIT COOLER THAN OBSERVED TODAY...WITH MOST READINGS REMAINING
THE 50S. ALSO OF NOTE...SHOWERS WILL BE ON THE INCREASE THROUGH THE
AFTERNOON AS A MID LEVEL SHORTWAVE WORKS IN CONJUNCTION WITH THE
RIGHT REAR ENTRANCE OF A STRONG UPPER JET MAX...PRECIPITATION WILL
SPREAD WEST TO EAST THROUGH THE AFTERNOON...AND SHOULD BECOME
FOCUSED ALONG AN AREA OF MIDLEVEL FRONTOGENETIC FORCING THAT APPEARS
TO BISECT THE CWA FROM SOUTHWEST TO NORTHEAST DURING THE AFTERNOON
HOURS /MAINLY THROUGH THE CENTRAL SANDHILLS/. PRECIPITATION CHANCES
BECOME MORE WIDESPREAD INTO THE EVENING HOURS AND OVERNIGHT AS DPVA
SPREADS EAST FROM ROCKIES ONTO THE NORTHERN HIGH PLAINS. ANALYSIS
OF THE 300-305K ISENTROPIC LAYER INDICATES SEVERAL HOURS /00-06Z
WEDNESDAY/ OF STRONG UPGLIDE TARGETING WESTERN AND NORTH CENTRAL
NEBRASKA...THEREAFTER DOWNGLIDE STARTS TO TAKE CONTROL WITH
CONDENSATION PRESSURE DEFICITS RAPIDLY RISING ABOVE 10MB...THUS CUT
BACK QPF AMOUNTS SOME ON WEDNESDAY WITH MOST LOCATIONS EXPECTING
LESS THAN A HALF OF AN INCH TOTAL QPF. ALSO TRIMMED POPS BACK INTO
THE LOW END CHANCE/SLIGHT CHANCE CATEGORY WEDNESDAY AFTERNOON AS
THE UPPER SUPPORT TRANSITIONS EAST WITH THE BEST UPGLIDE.
PROBLEMATIC TO THE FORECAST IS THE POTENTIAL FOR SNOW OR A RAIN/SNOW
MIX TUESDAY NIGHT AFTER MIDNIGHT THROUGH THE MORNING HOURS ON
WEDNESDAY...AS THE OPERATIONAL MODELS GENERATE AS MUCH AS FOUR TO
SIX INCHES ACROSS THE SANDHILLS...HOWEVER PROXIMITY SOUNDINGS
INDICATE FACTOR THAT MAY LIMIT OVERALL SNOW PRODUCTION AS THE
DENDRITIC LAYER IS CENTERED NEAR 500MB OVER SOUTHERN AND EASTERN
PORTIONS OF THE CWA /600-700 MB ACROSS THE NORTH AND
NORTHWEST/...AND GIVEN A RATHER SHORT PERIOD OF DEEP TROPOSPHERIC
MOISTURE...SNOW PRODUCTION MAY BE LIMITED. ANOTHER FACTOR AGAINST
ACCUMULATING SNOW IS THE RECENT WARM SPELL...WHICH HAS ALLOWED
GROUND TEMPERATURES TO CLIMB INTO THE 40S. SO FOR NOW WILL GO WITH
LIMITED TO NIL ACCUMULATIONS WITH THE IDEA THAT SUBSEQUENT
FORECASTS WILL HAVE A BETTER IDEA OF WHERE AND IF SNOW
ACCUMULATES.
A STRONG /~1040MB/ SURFACE HIGH WILL BUILD ACROSS THE HIGH PLAINS
EARLY ON THURSDAY AND REMAIN THROUGH FRIDAY MORNING...FROST AND/OR
FREEZE CONDITIONS WILL BE POSSIBLE.
THE UPPER PATTERN BECOMES STALE BY LATE WEEK WITH A CUTOFF LOW
FORMING AND REMAINING SOMEWHERE IN THE VICINITY OF THE LOWER
MISSOURI VALLEY. TEMPERATURES HEADING INTO THE WEEKEND SHOULD
SLOWLY MODERATE ACROSS OUR WESTERN ZONES...WITH THE
EAST...INFLUENCED BY THE UPPER LOW...REMAINING RATHER COOL. THE
LONGER RANGE SOLUTIONS CONTINUE TO INDICATE WRAP AROUND QPF POSSIBLY
AS FAR WEST AS HIGHWAY 61 THROUGH THE WEEKEND. CONFIDENCE IN STALE
PATTERNS USUALLY IS FAIRLY LOW...THUS WON/T MAKE ANY WHOLESALE
CHANGES TO THE EXTENDED PROCEDURE FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 102 PM CDT MON APR 29 2013
COLD FRONT WILL MOVE ACROSS THE AREA TOMORROW MORNING. UNTIL THEN
SOUTH TO SOUTHWEST WINDS...GUSTING TO 20 TO 25 KTS THIS AFTERNOON
BENEATH VFR SKIES. CLEAR SKIES WILL SEE SOME HIGH CLOUDS MOVE IN
FROM THE NW FOR THE AFTERNOON. INCREASING MID HIGH CLOUDS AHEAD OF
THE FRONT OVERNIGHT. LIMITED MOISTURE SO FRONTAL PASSAGE SHOULD BE
DRY...HOWEVER WILL SEE A DRAMATIC SWITCH TO N/NNW WINDS. AS THE
FRONT CONTINUES TO PUSH TO THE SOUTHEAST...WINDS WILL
INCREASE...GUSTING TO 15 TO 25 KTS BY LATE MORNING.
&&
.FIRE WEATHER...
ISSUED AT 353 AM CDT MON APR 29 2013
LOW PRESSURE DEEPENS ACROSS WRN SD THIS AFTERNOON TO AROUND 990 MB.
THIS SEND ANOTHER SURGE OF WEST/SOUTHWEST WINDS AND VERY DRY AIR
THROUGH THE PANHANDLE AND INTO NCNTL NEB. WINDS SHOULD INCREASE TO
15 TO 25 MPH WITH RH BETWEEN 10 AND 15 PERCENT. GREEN UP IS UNDERWAY
SO FUEL STATUS IS QUESTIONABLE FOR CRITICAL FIRE DANGER ACROSS NWRN
NEB. NO RED FLAG WARNING WILL BE ISSUED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...JACOBS
AVIATION...MASEK
FIRE WEATHER...CDC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
158 PM EDT MON APR 29 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE OVER THE EASTERN PART OF THE AREA WILL
WEAKEN AND MOVE NORTHEAST TODAY. HIGH PRESSURE WILL BUILD OVER THE
AREA TUESDAY INTO WEDNESDAY AND REMAIN IN PLACE INTO FRIDAY BEFORE
WEAKENING AND MOVING EAST. A LOW SHOULD APPROACH THE AREA FROM THE
WEST NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST HRRR MODEL SHOWS WEAK LINE OF SHOWERS EXPECTED TO CONTINUE
OVER NORTHEAST OHIO INTO NORTHWEST PENNSYLVANIA EARLY THIS
AFTERNOON. THIS IS ASSOCIATED WITH SURFACE TROUGH THAT WILL
EVENTUALLY PUSH EAST AND OUT OF THE REGION. WILL KEEP THE CHANCE
OF SHOWERS GOING IN THE EAST THROUGH THE AFTERNOON. IN THE
WEST...SOME CLEARING IS TRYING TO PUSH INTO NORTHWEST OHIO AND
THIS SHOULD SUPPORT SOME SUNSHINE THROUGH THE AFTERNOON.
ELSEWHERE...CLOUDS SHOULD HOLD IN WITH A FEW BREAKS IN THE
OVERCAST. DUE TO CLOUDS MOST AREAS AND SHOWERS EAST...WILL GO
AHEAD AND BUMP TEMPERATURES DOWN A FEW DEGREES. I STILL THINK THE
EAST WILL RECOVER SINCE WE STILL HAVE A FAIR AMOUNT OF DAYLIGHT
LEFT THIS AFTERNOON AND EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
MID AND UPPER RIDGING STARTING TO BUILD IN TONIGHT SHOULD CAUSE MOST
OF THE SHRA TO END DURING THE EVENING. LIGHT SOUTH WINDS WILL LIKELY
ALLOW FOR MORE PATCHY FOG TO DEVELOP TONIGHT.
THE MODELS CONTINUE TO SHOW THE HIGH TO THE NE HOLDING MOISTURE
AROUND 850 MB OVER THE EAST HALF OF THE CWA ON TUE AND EVEN PRODUCE
SOME LIGHT PRECIP. HAVING A HARD TIME SEEING TOO MUCH CONVECTION
DEVELOP DUE TO THE UPPER RIDGING SO WILL KEEP POPS TO ONLY A SLIGHT
CHANCE OR LESS.
SIMILAR SITUATION ON WED BUT THE MOISTURE AROUND 850 MB NOW SPREAD
OVER MOST OF THE AREA. NAM AGAIN HAS SOME LIGHT PRECIP OVER THE
CENTRAL PART OF THE CWA. GUIDANCE POPS LOW AND ONGOING FORECAST HAS
BEEN DRY SO WILL MAINTAIN THE CONTINUITY AND KEEP POPS AT 14% OR
LESS.
UPPER TROUGH MOVES EAST TO NEAR THE MS RIVER ON THU INDUCING A
SURFACE LOW TO NOSE NE INTO INDIANA BY LATER IN THE DAY. UPPER
RIDGING SHOULD HOLD OFF THE PRECIP IN THE EAST. THE FAR WEST LOOKS
TO HAVE TOO MUCH MOISTURE TO WORK WITH ALONG WITH A LITTLE BETTER
DYNAMICS SO SOME CONVECTION CAN`T BE RULED OUT. THUS WILL ADD A
SLIGHT CHANCE POP IN FOR THAT AREA WHICH WILL ALSO COLLABORATE
BETTER WITH BORDERING FORECASTS.
TEMPS SHOULD WARM TUE INTO WED THEN STAY ABOVE NORMAL FOR THU.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LONG TERM BEGINS ON FRIDAY WITH THE GFS AND ECMWF FAIRLY CONSISTENT
IN THE PLACEMENT OF WHAT WILL BECOME A CUTOFF UPPER LOW OVER THE
NATIONS MID SECTION. 12Z FRIDAY THE MODELS HAVE THE LOW NEAR KANSAS
CITY WHILE AN UPPER HIGH WILL BE OVER PA AND NY INFLUENCING THE AREA
FROM THE EAST. MEANWHILE WESTERN COUNTIES WILL HAVE INCREASED
MOISTURE FROM THE FLOW AROUND THE LOW. SYSTEMS REMAIN NEARLY
STATIONARY THROUGH SUNDAY THEN BEGIN TO MOVE EAST SUNDAY NIGHT AND
MONDAY. IN GENERAL WILL HAVE CHANCE POPS FOR SHOWERS OR
THUNDERSTORMS WEST WITH MORE CLOUD COVER VS EAST. SATURDAY NIGHT AND
SUNDAY WILL HAVE CHANCE POPS FOR THE ENTIRE AREA AS MOISTURE SHIFTS
EAST. TEMPS MILD WITH NORMAL TO A FEW DEGREES ABOVE NORMAL TEMPS
EXPECTED.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
SCATTERED SHOWERS CONTINUE TO AFFECT PORTIONS OF NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA THIS AFTERNOON AS A WEAK SURFACE TROUGH MOVES
EAST OF THE AREA. EASTERN TAF SITES ARE A MIX OF MVFR AND VFR THIS
AFTERNOON...AND WILL LIKELY HOVER AROUND THIS THRESHOLD FOR THE NEXT
SIX HOURS. DRIER AIR IS BUILDING IN BEHIND THE TROUGH...BUT LOW
LEVEL MOISTURE REMAINS. THE LOW LEVEL MOISTURE COMBINED WITH LIGHT
WINDS WILL HELP IN THE DEVELOPMENT OF FOG AND LOW LEVEL STRATUS IN
THE OVERNIGHT TO EARLY MORNING HOURS. MVFR TO IFR VISIBILITIES ARE
EXPECTED WITH THE FOG...ESPECIALLY AFTER 08Z. FOG WILL DISSIPATE BY
ABOUT 13Z AS THE SURFACE BEGINS TO HEAT. VFR CEILINGS WILL PERSIST
THROUGH THE REST OF THE TAF PERIOD.
.OUTLOOK...NON-VFR POSSIBLE TUESDAY MORNING...THURSDAY MORNING AND
FRIDAY MORNING.
&&
.MARINE...
FOR TODAY LOOKING FOR SOUTH TO SOUTHWEST FLOW BEHIND A WEAK SURFACE
TROF MOVING ACROSS THE REGION. TONIGHT THROUGH FRIDAY...EXPECTING
GENERALLY SOUTH TO SOUTHEAST FLOW FOR MUCH OF THE PERIOD WITH HIGH
PRESSURE TO OUR EAST AND LOW PRESSURE WEST OF THE AREA. NO
HEADLINES ANTICIPATED.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...TK
AVIATION...YEAGER
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1232 PM EDT MON APR 29 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE OVER THE EASTERN PART OF THE AREA WILL
WEAKEN AND MOVE NORTHEAST TODAY. HIGH PRESSURE WILL BUILD OVER THE
AREA TUESDAY INTO WEDNESDAY AND REMAIN IN PLACE INTO FRIDAY BEFORE
WEAKENING AND MOVING EAST. A LOW SHOULD APPROACH THE AREA FROM THE
WEST NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST HRRR MODEL SHOWS WEAK LINE OF SHOWERS EXPECTED TO CONTINUE
OVER NORTHEAST OHIO INTO NORTHWEST PENNSYLVANIA EARLY THIS
AFTERNOON. THIS IS ASSOCIATED WITH SURFACE TROUGH THAT WILL
EVENTUALLY PUSH EAST AND OUT OF THE REGION. WILL KEEP THE CHANCE
OF SHOWERS GOING IN THE EAST THROUGH THE AFTERNOON. IN THE
WEST...SOME CLEARING IS TRYING TO PUSH INTO NORTHWEST OHIO AND
THIS SHOULD SUPPORT SOME SUNSHINE THROUGH THE AFTERNOON.
ELSEWHERE...CLOUDS SHOULD HOLD IN WITH A FEW BREAKS IN THE
OVERCAST. DUE TO CLOUDS MOST AREAS AND SHOWERS EAST...WILL GO
AHEAD AND BUMP TEMPERATURES DOWN A FEW DEGREES. I STILL THINK THE
EAST WILL RECOVER SINCE WE STILL HAVE A FAIR AMOUNT OF DAYLIGHT
LEFT THIS AFTERNOON AND EVENING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
MID AND UPPER RIDGING STARTING TO BUILD IN TONIGHT SHOULD CAUSE MOST
OF THE SHRA TO END DURING THE EVENING. LIGHT SOUTH WINDS WILL LIKELY
ALLOW FOR MORE PATCHY FOG TO DEVELOP TONIGHT.
THE MODELS CONTINUE TO SHOW THE HIGH TO THE NE HOLDING MOISTURE
AROUND 850 MB OVER THE EAST HALF OF THE CWA ON TUE AND EVEN PRODUCE
SOME LIGHT PRECIP. HAVING A HARD TIME SEEING TOO MUCH CONVECTION
DEVELOP DUE TO THE UPPER RIDGING SO WILL KEEP POPS TO ONLY A SLIGHT
CHANCE OR LESS.
SIMILAR SITUATION ON WED BUT THE MOISTURE AROUND 850 MB NOW SPREAD
OVER MOST OF THE AREA. NAM AGAIN HAS SOME LIGHT PRECIP OVER THE
CENTRAL PART OF THE CWA. GUIDANCE POPS LOW AND ONGOING FORECAST HAS
BEEN DRY SO WILL MAINTAIN THE CONTINUITY AND KEEP POPS AT 14% OR
LESS.
UPPER TROUGH MOVES EAST TO NEAR THE MS RIVER ON THU INDUCING A
SURFACE LOW TO NOSE NE INTO INDIANA BY LATER IN THE DAY. UPPER
RIDGING SHOULD HOLD OFF THE PRECIP IN THE EAST. THE FAR WEST LOOKS
TO HAVE TOO MUCH MOISTURE TO WORK WITH ALONG WITH A LITTLE BETTER
DYNAMICS SO SOME CONVECTION CAN`T BE RULED OUT. THUS WILL ADD A
SLIGHT CHANCE POP IN FOR THAT AREA WHICH WILL ALSO COLLABORATE
BETTER WITH BORDERING FORECASTS.
TEMPS SHOULD WARM TUE INTO WED THEN STAY ABOVE NORMAL FOR THU.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
LONG TERM BEGINS ON FRIDAY WITH THE GFS AND ECMWF FAIRLY CONSISTENT
IN THE PLACEMENT OF WHAT WILL BECOME A CUTOFF UPPER LOW OVER THE
NATIONS MID SECTION. 12Z FRIDAY THE MODELS HAVE THE LOW NEAR KANSAS
CITY WHILE AN UPPER HIGH WILL BE OVER PA AND NY INFLUENCING THE AREA
FROM THE EAST. MEANWHILE WESTERN COUNTIES WILL HAVE INCREASED
MOISTURE FROM THE FLOW AROUND THE LOW. SYSTEMS REMAIN NEARLY
STATIONARY THROUGH SUNDAY THEN BEGIN TO MOVE EAST SUNDAY NIGHT AND
MONDAY. IN GENERAL WILL HAVE CHANCE POPS FOR SHOWERS OR
THUNDERSTORMS WEST WITH MORE CLOUD COVER VS EAST. SATURDAY NIGHT AND
SUNDAY WILL HAVE CHANCE POPS FOR THE ENTIRE AREA AS MOISTURE SHIFTS
EAST. TEMPS MILD WITH NORMAL TO A FEW DEGREES ABOVE NORMAL TEMPS
EXPECTED.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
WEAK SURFACE TROF EXTENDING SOUTH FROM THE ISLANDS THROUGH OHIO.
SHOWERS ARE MAINLY EAST OF THE TROF IN A MIX OF MVFR AND IFR
CONDITIONS ACROSS THE ENTIRE AREA. EXPECTING IFR CONDITIONS TO
AFFECT MUCH OF THE AREA INTO THE MORNING HOURS...LIFTING TO MVFR
THROUGH THE LATE MORNING AND EARLY AFTERNOON AS DRIER AIR
EVENTUALLY BEGINS TO MOVE IN FROM THE WEST. CONCERNED THAT WITH
LIGHT FLOW DRYING ALOFT AND LEFTOVER LOW LEVEL MOISTURE...FOG AND
POSSIBLY A LOW STRATUS WILL REDEVELOP TONIGHT.
.OUTLOOK...NON-VFR POSSIBLE TUESDAY MORNING...THURSDAY MORNING AND
FRIDAY MORNING.
&&
.MARINE...
FOR TODAY LOOKING FOR SOUTH TO SOUTHWEST FLOW BEHIND A WEAK SURFACE
TROF MOVING ACROSS THE REGION. TONIGHT THROUGH FRIDAY...EXPECTING
GENERALLY SOUTH TO SOUTHEAST FLOW FOR MUCH OF THE PERIOD WITH HIGH
PRESSURE TO OUR EAST AND LOW PRESSURE WEST OF THE AREA. NO
HEADLINES ANTICIPATED.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
531 PM EDT MON APR 29 2013
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL STRENGTHEN ATOP THE REGION THROUGH
MIDWEEK AND LINGER INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 530 PM...LATEST RUC AND WATER VAPOR IMAGERY SHOW THE AXIS OF A
SHORT WAVE ALREADY EAST OF THE NC FOOTHILLS. NVA BEHIND THIS FEATURE
WAS APPARENTLY DOING ITS BEST TO SQUASH ANY OF THE ENHANCED CU FROM
GROWING TO ANY GREAT EXTENT. THE KGSP WAS RELATIVELY QUIET AND
EXPECT IT TO STAY THAT WAY. HAVE KNOCKED THE POP DOWN TO KEEP IT IN
THE SLIGHT CHANCE RANGE THROUGH THE EARLY PART OF THE EVENING.
PREVIOUS DISCUSSION...
AS OF 230 PM EDT MONDAY...A SHORT WAVE TROUGH WILL PUSH EAST OF THE
REGION THIS EVENING. NVA AND DEEP LAYER RIDGING WILL FOLLOW IN IT/S
WAKE. THERE COULD STILL BE SOME SHOWER OR THUNDERSTORM ACTIVITY LATE
THIS AFTERNOON AND EVENING...PARTICULARLY ALONG THE BLUE RIDGE AND
OUT ACROSS THE NC FOOTHILLS. SO I/VE HELD ON TO SOME LOW END CHANCE
POPS ACROSS THESE ZONES. LATER TONIGHT THE STAGE LOOKS SET FOR
WIDESPREAD DENSE FOG. THE NAM CONDENSATION PRESSURE DEFICITS FALL TO
ZERO ACROSS ALL OF THE FA EXCEPT THE MTN RIDGE-TOPS. THERE WILL BE
DEEP LAYER DRYING AND WINDS WILL BE LIGHT. WE HAD WIDESPREAD RAIN
OVER THE PAST COUPLE DAYS AND THE GROUND IS QUITE MOIST. I DEBATED
ISSUING A DENSE FOG ADVISORY...BUT THERE IS JUST ENOUGH LLVL FLOW
THAT A LOW STRATUS DECK COULD DEVELOP INSTEAD. ALSO...THE
NEIGHBORING OFFICES I SPOKE WITH WERE INCLINED TO WAIT ON ISSUING AN
ADVISORY AND THAT/S WHAT I WILL DO AS WELL. STILL...I DO HAVE
WIDESPREAD DENSE FOG IN THE GRIDS AND I/LL HIT IT IN THE HWO.
THAT DEEP LAYER RIDGE REMAINS OVERHEAD ON TUESDAY. WINDS WILL BE
LIGHT AND THE NAM SOUNDINGS ARE SHOWING A PRONOUNCED INVERSION. A
FEW SHRA ARE POSSIBLE ACROSS THE NC MTNS...BUT I/VE PULLED POPS OVER
THE FOOTHILLS AND PIEDMONT. IT WILL BE A MILD DAY WITH NEAR SEASONAL
TEMPERATURES.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 145 PM MONDAY...AVERAGE MODEL AGREEMENT IN THE SHORT
TERM...GIVEN SUBTLE UPPER FEATURES AND OVERALL WEAK FORCING ACRS THE
CWFA. AN UPPER RIDGE WILL BUILD OVER THE EASTERN GREAT LAKES THRU
THE PERIOD...WHILE A WEAK AREA OF LOW PRES WILL LINGER INVOF THE
EASTERN GULF/FL. THIS PATTERN WILL SET UP A DEEP ELY FLOW...WITH AN
INVERTED TROF OFF THE CAROLINA COASTS AND HIGH PRES ANCHORED OVR NEW
ENGLAND WITH A WEDGE SW DOWN THE ENTIRE APPALACHIAN CHAIN. THERE ARE
SUBTLE DIFFERENCES AMONG THE OP MODELS ON A COUPLE OF WEAK WAVES
IN THE LLVL ELY FLOW. OVERALL...THE GFS IS MORE STABLE WITH AN
ATLANTIC MARINE LAYER AND STRONGER WEDGE THAN THE NAM. A LOOK AT THE
STRENGTH OF THE FLOW (850 MB WINDS GENERALLY UNDER 25 KTS) AND LACK
OF UPPER Q-VECTOR CONVERGENCE...I THINK TUESDAY NIGHT AND WEDNESDAY
WILL BE GENERALLY DRY. THE SW NC MTNS LOOK TO HAVE THE MOST INSTBY
AND WITH MTN-TOP CONVERGENCE...MAY HAVE A FEW SHWRS/TSTMS WED AFTN.
OTHERWISE...EXPECTING AN INCREASE IN STRATOCUMULUS BY DAYBREAK
WEDNESDAY...BREAKING UP SOMEWHAT DURING THE DAY. TEMPS WILL BE NEAR
NORMAL FOR LOWS...AND ABOUT A CATEGORY BELOW NORMAL FOR HIGHS.
THERE SEEMS TO BE A CONSENSUS ON A SURGE IN 850-700 MB ATLANTIC
MOISTURE ADVECTING IN...AS FLOW VEERS FROM ENE TO ESE WEDNESDAY
NIGHT INTO THURSDAY (PASSAGE OF AN ELY WAVE). MEANWHILE...A
SUBSIDENCE INVERSION STRENGTHENS IN BOTH THE NAM AND GFS SNDGS ATOP
THE MOIST LAYER. THIS INVERSION SETS UP AROUND 700-600 MB LAYER BY
THURSDAY AFTN. THE NAM AND GFS 295 K SFC BOTH SHOW SOME MOIST
UPGLIDE. PERSISTING FROM ABOUT 06Z THURSDAY TILL 00Z FRIDAY . THAT
ALONG WILL ELY UPSLOPE FLOW ALONG THE BLUE RIDGE SEEMS TO WARRANT
KEEPING A SHOTGUN LOW-END CHC POP EARLY THURSDAY MORNING...THEN
TAPERING OFF IN THE NE HALF OF THE CWFA THURSDAY AFTN...AS DRY AIR
WORKS BACK IN. MIN TEMPS SIMILAR TO TUESDAY NIGHT...BUT EXPECTING
COOLER TEMPS ON THURSDAY AS THICKNESSES FALL UNDER THE WEDGE
(GENERALLY UPR 60S TO LWR 70S).
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 200 PM MONDAY...THE LATEST AVAILABLE MEDIUM RANGE GUIDANCE IS
STILL PROGGING THE CWFA TO BE WITHIN A MOISTURE AND FORCING MINIMA
ON FRIDAY AND IT IS DEBATABLE IF THE LLVL EASTERLY FLOW WILL BE ENUF
TO FORCE ANYTHING MORE THAN A FEW SHOWERS WHICH I DOUBT. MAX TEMPS
ARE SLATED TO BE COOL FOR EARLY MAY...SVRL CATEGORIES BELOW CLIMO.
OMEGA BLOCKING PATTERN CONTINUES INTO THE WEEKEND...AND WITH THE
29/12 UTC OP GFS RUN TO RUN INCONSISTENCY IN HANDLING PLAINS UPPER
LOW MOVEMENT...PREFER TO LEAN TO 29/00 UTC OP ECMWF WITH RESPECT TO
UPPER RIDGE POSITION. BASED ON THIS...WILL PLAN ON ROUGHLY A COOL
PERSISTENCE FCST FOR SATURDAY AND SUNDAY WITH JUST A TOKEN SHOWER
CHANCE EACH DAY WITH TEMPS BY MONDAY GETTING CLOSER TO CLIMO.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
AT KCLT AND ELSEWHERE...CIGS WILL SLOWLY LIFT INTO THE VFR RANGE BY
LATE AFTN. WINDS WILL GENERALLY BE OUT OF THE SOUTHWEST AT SPEEDS
LESS THAN 10 KTS. IT DOESN/T APPEAR THAT MUCH SHOWER ACTIVITY WILL
DEVELOP...AND THE TEMPO GROUPS FOR SHRA HAVE BEEN REMOVED. THE BIG
NEWS IS THE FOG POTENTIAL FOR TONIGHT. SEVERAL FACTORS SUGGEST DENSE
FOG LATER TONIGHT OVER MOST OF THE REGION. IT WILL BE DRY ALOFT. THE
LLVL WINDS WILL BE LIGHT...WHICH SHOULD KEEP ORGANIZED STRATUS FROM
DEVELOPING. RECENT WIDESPREAD RAIN HAS RESULTED IN VERY MOIST SOIL
CONDITIONS. THEREFORE I/VE ADDED FOG TO ALL THE TAFS FOR TONIGHT.
I/VE CAPPED THE LOWER END OF THE VSBY AT 1/2SM AT MANY
SITES...THOUGH I SUSPECT MOST AIRFIELDS WILL SEE 1/4SM FOR SEVERAL
HOURS LATE TONIGHT.
OUTLOOK...MORNING LOW CLOUDS AND FOG...WITH A SMALL CHANCE OF
AFTERNOON SHOWERS/THUNDERSTORMS EACH DAY THROUGH AT LEAST MID WEEK.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT MED 64% LOW 59% MED 67% HIGH 94%
KGSP HIGH 100% MED 67% LOW 40% HIGH 86%
KAVL HIGH 97% MED 79% MED 62% MED 68%
KHKY HIGH 98% MED 75% LOW 54% HIGH 98%
KGMU HIGH 100% MED 72% LOW 57% HIGH 84%
KAND HIGH 92% MED 78% MED 66% HIGH 84%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...MCAVOY/PM
SHORT TERM...ARK
LONG TERM...CSH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
420 PM CDT MON APR 29 2013
UPDATED TO ADD SMALL CRAFT ADVISORY MARINE ZONE CODING.
.VERY SHORT TERM...TONIGHT AND TUESDAY. FORECAST CONFIDENCE IS
MEDIUM.
LINE OF ELEVATED SHOWERS AND A FEW THUNDERSTORMS SHIFTING EAST
NORTHEAST THROUGH THE AREA AT THIS TIME...BEING FED BY SOUTH
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE. THESE SHOULD CONTINUE TO
MOVE THROUGH THE REMAINDER OF THE AREA LATE THIS AFTERNOON.
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE WILL CONTINUE TO POINT INTO
THE AREA TONIGHT...GRADUALLY INCREASING IN MAGNITUDE. WARM AIR
ADVECTION KICKS IN TONIGHT AS WELL. TAIL END OF 500MB VORTICITY
MAXIMUM OVER SOUTHERN MINNESOTA WILL SHIFT CLIP THE NORTHERN
PORTIONS OF THE AREA THROUGH EARLY EVENING...WITH ANOTHER OVER
EASTERN NEBRASKA SHIFTING INTO THE AREA BY 06Z TUESDAY.
ADJUSTING AREA FORECAST SOUNDINGS FOR LOWER TO MID 50S DEW POINTS
YIELD MEAN LAYER CAPES OF UP TO 500 J/KG INTO EARLY EVENING...THEN
SHOW ELEVATED CAPES INCREASING TONIGHT OVER 1000 J/KG. THIS IS IN
RESPONSE TO MOISTURE BUILDING IN THE 925MB TO 850MB LEVEL. DEEP
LAYER SHEAR IS STRONG INTO EARLY EVENING...THEN WEAKENS SOMEWHAT
LATER TONIGHT AS MID LEVEL WINDS WEAKEN. SPC HAS SLIGHT RISK AREA
INTO JUST THE FAR SOUTHWESTERN SECTIONS OF THE AREA. MAIN RISK
APPEARS TO BE IN IOWA...THOUGH IF HIGHER DEW POINTS MOVE IN AND
INCREASE CAPE THIS EVENING...COULD SEE A SEVERE STORM OR TWO OCCUR.
4KM WRF/NMM MODEL SHOWING SPOTTY SHOWERS AND A FEW STORMS THIS
EVENING...WITH A MORE ORGANIZED AREA OF SHOWERS AND STORMS FOR LATER
TONIGHT WITH LOW LEVEL JET FORCING. HRRR KEEPING BULK OF CONVECTION
JUST SOUTH AND SOUTHWEST OF THE AREA TONIGHT. FOR NOW...WILL GO WITH
SCATTERED SHOWERS AND ISOLATED STORMS EARLY THIS EVENING...WITH
THUNDER FOR LATER THIS EVENING AND OVERNIGHT.
MODELS SHOWING WARM SECTOR AIRMASS MOVING INTO THE AREA
TUESDAY...CAPPING OFF THE AREA FROM PRECIPITATION. GUSTY
SOUTH/SOUTHWEST WINDS AND EXPECTED 925MB TEMPERATURES SHOULD BRING
HIGHS INTO THE LOWER 80S IN MOST AREAS. COOLER VALUES NEAR SHEBOYGAN
WITH SOUTH ONSHORE WINDS. APPROACHING COLD FRONT LATER IN THE
AFTERNOON SHOULD BRING INCREASED CHANCES FOR THUNDERSTORMS...THOUGH
BEST SHOT IS INTO TUESDAY NIGHT.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE LOW TO MEDIUM.
THUNDERSTORMS ALONG AND AHEAD OF THE FRONTAL BOUNDARY ONGOING AT THE
BEGINNING OF THE PERIOD EXPECTED TO TRANSITION TO MAINLY RAIN
SHOWERS FROM NORTHWEST TO SOUTHEAST BEHIND THE FRONT ON WEDNESDAY AS
IT SAGS THROUGH THE FORECAST AREA. THOUGH SURFACE FRONT MAKES IT TO
OR NEAR SE WI BY 12Z WED...UPPER TROUGH STILL WELL TO THE WEST AND
WILL KEEP THE FOCUS FOR PRECIPITATION THROUGH IOWA INTO WESTERN WI.
WILL KEEP CHANCE POPS ALONG THE FRONT.
LOWS WILL NOT FALL OFF MUCH TUESDAY NIGHT UNTIL LATE IN THE
NW...THEN WARM SE WEDNESDAY AHEAD OF STALLED BAROCLINIC ZONE
BISECTING THE CWA...THOUGH COOLER ALONG THE LAKE.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM.
LIKELY POPS INTO THE WESTERN CWA WITH INCREASING FORCING AHEAD OF
SLOWLY APPROACHING TROUGH AS IT DEEPENS OVER THE CENTRAL U.S.
MODELS STILL DIFFER WITH THE PLACEMENT OF BAROCLINIC ZONE WHICH
AFFECTS NOT ONLY TEMPERATURES BUT LOCATION OF BETTER LOW TO MID
LEVEL FRONTOGENESIS AND Q-VECTOR CONVERGENCE.
BLENDED SOLUTION KEEPS LIKELY POPS OVER SOUTH CENTRAL WI THROUGH THE
DAY THURSDAY...THEN SHIFT ACROSS THE ENTIRE CWA THURSDAY NIGHT.
THERMAL RIDGE NOSING INTO THE FAR SOUTH WILL BRING HIGHS IN THE
UPPER 50S THERE...THEN TAPER OFF TO THE MID 40S NW WITH UPPER 40S
ALONG THE LAKE.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE...
LOW.
MODELS STILL TRYING TO GET A HANDLE ON LOW CUTTING-OFF OVER THE
CENTRAL PLAINS THURSDAY NIGHT AND THEN LIFTING SLOWLY NWD INTO THE
UPPER MIDWEST SUNDAY. SOME THERMAL DIFFERENCES THAT MAY IMPACT
PRECIPITATION TYPE AND BRING SOME SNOWFLAKES MIXING IN WITH THE RAIN
IN THE FAR WEST/NW LATE THURSDAY NIGHT...BUT WILL LEAVE ALL LIQUID
FOR NOW. OTHERWISE A CLOUDY...COOL AND WET PERIOD THROUGH THE
WEEKEND WITH TEMPERATURES STRUGGLING INTO THE LOWER 50S...COOLER BY
THE LAKE WITH GENERALLY EASTERLY FLOW. PERIODS OF RAIN...WITH
INTENSITY DEPENDENT ON STRENGTH OF VORTICITY MAXIMA ROTATING THROUGH
THE REGION AND THE AMOUNT OF AVAILABLE MOISTURE WITH STREAMERS OF
DRIER AIR WRAPPING AROUND CIRCULATION. SOME HOPE THAT THE LOW WILL
LIFT FAR ENOUGH AWAY BY MONDAY TO LOWER RAIN CHANCES AND ALLOW
WARMER TEMPS.
AVIATION/00Z TAFS/...
VFR CONDITIONS ARE EXPECTED THIS EVENING ACROSS TAF SITES. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS MOVING THROUGH AT THIS TIME...WITH
MORE AT TIMES MAINLY LATER TONIGHT INTO EARLY TUESDAY MORNING. THERE
WILL BE LULLS IN THE PRECIPITATION.
FOR NOW...WILL KEEP VICINITY THUNDER WORDING IN TAFS...AS THERE IS
SOME UNCERTAINTY WITH THE EXACT TIMING AND AREAL COVERAGE OF THE
SHOWERS AND STORMS. ANY STORMS WOULD BRING VISIBILITIES DOWN TO
NEAR ALTERNATE MINIMUMS...WITH MVFR CEILINGS.
SOUTH WINDS TONIGHT WILL GRADUALLY INCREASE AND SHIFT SOUTHWEST BY
TUESDAY AFTERNOON. GUSTS TO 25 KNOTS OR SO ARE EXPECTED BY TUESDAY
AFTERNOON.
MARINE...
A TIGHT PRESSURE GRADIENT WILL DEVELOP OVER THE NEARSHORE WATERS
TUESDAY...WHICH WILL RESULT IN GUSTY SOUTH WINDS. FREQUENT GUSTS TO
25 KNOTS ARE EXPECTED. THUS...A SMALL CRAFT ADVISORY WILL BE ISSUED
FROM MID MORNING THROUGH EARLY EVENING TUESDAY.
ANOTHER TIGHT PRESSURE GRADIENT WILL DEVELOP WITH THE INFLUX OF
COLDER AIR FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THIS WILL
BRING BRISK AND GUSTY NORTH TO NORTHEAST WINDS DURING THIS
TIME...ALONG WITH HIGH WAVES. A SMALL CRAFT ADVISORY MAY BE NEEDED
DURING THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 10 AM TO 7 PM CDT TUESDAY FOR
LMZ643>646.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
349 PM CDT MON APR 29 2013
.VERY SHORT TERM...TONIGHT AND TUESDAY. FORECAST CONFIDENCE IS MEDIUM.
LINE OF ELEVATED SHOWERS AND A FEW THUNDERSTORMS SHIFTING EAST
NORTHEAST THROUGH THE AREA AT THIS TIME...BEING FED BY SOUTH
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE. THESE SHOULD CONTINUE TO
MOVE THROUGH THE REMAINDER OF THE AREA LATE THIS AFTERNOON.
SOUTHWESTERLY 850MB LOW LEVEL JET NOSE WILL CONTINUE TO POINT INTO
THE AREA TONIGHT...GRADUALLY INCREASING IN MAGNITUDE. WARM AIR
ADVECTION KICKS IN TONIGHT AS WELL. TAIL END OF 500MB VORTICITY
MAXIMUM OVER SOUTHERN MINNESOTA WILL SHIFT CLIP THE NORTHERN
PORTIONS OF THE AREA THROUGH EARLY EVENING...WITH ANOTHER OVER
EASTERN NEBRASKA SHIFTING INTO THE AREA BY 06Z TUESDAY.
ADJUSTING AREA FORECAST SOUNDINGS FOR LOWER TO MID 50S DEW POINTS
YIELD MEAN LAYER CAPES OF UP TO 500 J/KG INTO EARLY EVENING...THEN
SHOW ELEVATED CAPES INCREASING TONIGHT OVER 1000 J/KG. THIS IS IN
RESPONSE TO MOISTURE BUILDING IN THE 925MB TO 850MB LEVEL. DEEP
LAYER SHEAR IS STRONG INTO EARLY EVENING...THEN WEAKENS SOMEWHAT
LATER TONIGHT AS MID LEVEL WINDS WEAKEN. SPC HAS SLIGHT RISK AREA
INTO JUST THE FAR SOUTHWESTERN SECTIONS OF THE AREA. MAIN RISK
APPEARS TO BE IN IOWA...THOUGH IF HIGHER DEW POINTS MOVE IN AND
INCREASE CAPE THIS EVENING...COULD SEE A SEVERE STORM OR TWO OCCUR.
4KM WRF/NMM MODEL SHOWING SPOTTY SHOWERS AND A FEW STORMS THIS
EVENING...WITH A MORE ORGANIZED AREA OF SHOWERS AND STORMS FOR LATER
TONIGHT WITH LOW LEVEL JET FORCING. HRRR KEEPING BULK OF CONVECTION
JUST SOUTH AND SOUTHWEST OF THE AREA TONIGHT. FOR NOW...WILL GO WITH
SCATTERED SHOWERS AND ISOLATED STORMS EARLY THIS EVENING...WITH
THUNDER FOR LATER THIS EVENING AND OVERNIGHT.
MODELS SHOWING WARM SECTOR AIRMASS MOVING INTO THE AREA
TUESDAY...CAPPING OFF THE AREA FROM PRECIPITATION. GUSTY
SOUTH/SOUTHWEST WINDS AND EXPECTED 925MB TEMPERATURES SHOULD BRING
HIGHS INTO THE LOWER 80S IN MOST AREAS. COOLER VALUES NEAR SHEBOYGAN
WITH SOUTH ONSHORE WINDS. APPROACHING COLD FRONT LATER IN THE
AFTERNOON SHOULD BRING INCREASED CHANCES FOR THUNDERSTORMS...THOUGH
BEST SHOT IS INTO TUESDAY NIGHT.
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE LOW TO MEDIUM.
THUNDERSTORMS ALONG AND AHEAD OF THE FRONTAL BOUNDARY ONGOING AT THE
BEGINNING OF THE PERIOD EXPECTED TO TRANSITION TO MAINLY RAIN
SHOWERS FROM NORTHWEST TO SOUTHEAST BEHIND THE FRONT ON WEDNESDAY AS
IT SAGS THROUGH THE FORECAST AREA. THOUGH SURFACE FRONT MAKES IT TO
OR NEAR SE WI BY 12Z WED...UPPER TROUGH STILL WELL TO THE WEST AND
WILL KEEP THE FOCUS FOR PRECIPITATION THROUGH IOWA INTO WESTERN WI.
WILL KEEP CHANCE POPS ALONG THE FRONT.
LOWS WILL NOT FALL OFF MUCH TUESDAY NIGHT UNTIL LATE IN THE
NW...THEN WARM SE WEDNESDAY AHEAD OF STALLED BAROCLINIC ZONE
BISECTING THE CWA...THOUGH COOLER ALONG THE LAKE.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM.
LIKELY POPS INTO THE WESTERN CWA WITH INCREASING FORCING AHEAD OF
SLOWLY APPROACHING TROUGH AS IT DEEPENS OVER THE CENTRAL U.S.
MODELS STILL DIFFER WITH THE PLACEMENT OF BAROCLINIC ZONE WHICH
AFFECTS NOT ONLY TEMPERATURES BUT LOCATION OF BETTER LOW TO MID
LEVEL FRONTOGENESIS AND Q-VECTOR CONVERGENCE.
BLENDED SOLUTION KEEPS LIKELY POPS OVER SOUTH CENTRAL WI THROUGH THE
DAY THURSDAY...THEN SHIFT ACROSS THE ENTIRE CWA THURSDAY NIGHT.
THERMAL RIDGE NOSING INTO THE FAR SOUTH WILL BRING HIGHS IN THE
UPPER 50S THERE...THEN TAPER OFF TO THE MID 40S NW WITH UPPER 40S
ALONG THE LAKE.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE...
LOW.
MODELS STILL TRYING TO GET A HANDLE ON LOW CUTTING-OFF OVER THE
CENTRAL PLAINS THURSDAY NIGHT AND THEN LIFTING SLOWLY NWD INTO THE
UPPER MIDWEST SUNDAY. SOME THERMAL DIFFERENCES THAT MAY IMPACT
PRECIPITATION TYPE AND BRING SOME SNOWFLAKES MIXING IN WITH THE RAIN
IN THE FAR WEST/NW LATE THURSDAY NIGHT...BUT WILL LEAVE ALL LIQUID
FOR NOW. OTHERWISE A CLOUDY...COOL AND WET PERIOD THROUGH THE
WEEKEND WITH TEMPERATURES STRUGGLING INTO THE LOWER 50S...COOLER BY
THE LAKE WITH GENERALLY EASTERLY FLOW. PERIODS OF RAIN...WITH
INTENSITY DEPENDENT ON STRENGTH OF VORTICITY MAXIMA ROTATING THROUGH
THE REGION AND THE AMOUNT OF AVAILABLE MOISTURE WITH STREAMERS OF
DRIER AIR WRAPPING AROUND CIRCULATION. SOME HOPE THAT THE LOW WILL
LIFT FAR ENOUGH AWAY BY MONDAY TO LOWER RAIN CHANCES AND ALLOW
WARMER TEMPS.
&&
.AVIATION/00Z TAFS/...
VFR CONDITIONS ARE EXPECTED THIS EVENING ACROSS TAF SITES. SCATTERED
SHOWERS AND A FEW THUNDERSTORMS MOVING THROUGH AT THIS TIME...WITH
MORE AT TIMES MAINLY LATER TONIGHT INTO EARLY TUESDAY MORNING. THERE
WILL BE LULLS IN THE PRECIPITATION.
FOR NOW...WILL KEEP VICINITY THUNDER WORDING IN TAFS...AS THERE IS
SOME UNCERTAINTY WITH THE EXACT TIMING AND AREAL COVERAGE OF THE
SHOWERS AND STORMS. ANY STORMS WOULD BRING VISIBILITIES DOWN TO
NEAR ALTERNATE MINIMUMS...WITH MVFR CEILINGS.
SOUTH WINDS TONIGHT WILL GRADUALLY INCREASE AND SHIFT SOUTHWEST BY
TUESDAY AFTERNOON. GUSTS TO 25 KNOTS OR SO ARE EXPECTED BY TUESDAY
AFTERNOON.
&&
.MARINE...
A TIGHT PRESSURE GRADIENT WILL DEVELOP OVER THE NEARSHORE WATERS
TUESDAY...WHICH WILL RESULT IN GUSTY SOUTH WINDS. FREQUENT GUSTS TO
25 KNOTS ARE EXPECTED. THUS...A SMALL CRAFT ADVISORY WILL BE ISSUED
FROM MID MORNING THROUGH EARLY EVENING TUESDAY.
ANOTHER TIGHT PRESSURE GRADIENT WILL DEVELOP WITH THE INFLUX OF
COLDER AIR FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THIS WILL
BRING BRISK AND GUSTY NORTH TO NORTHEAST WINDS DURING THIS
TIME...ALONG WITH HIGH WAVES. A SMALL CRAFT ADVISORY MAY BE NEEDED
DURING THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1240 PM CDT MON APR 29 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 354 AM CDT MON APR 29 2013
A VERY ACTIVE WEATHER PATTERN IN STORE FOR THE REGION THIS WEEK.
FIRST OFF...WILL BE WATCHING A WEAK COLD FRONT SAGGING SOUTH ACROSS
THE AREA TODAY. TWO SHORTWAVE TROUGHS ARE EXPECTED TO MOVE ACROSS
THE UPPER MISSISSIPPI RIVER VALLEY TODAY AND INTERACT WITH THE FRONT
AS IT EDGES SOUTH...SPARKING OFF SHOWERS AND THUNDERSTORMS. THE
FIRST LEADING SHORTWAVE WAS RACING EAST ACROSS SOUTH DAKOTA EARLY
THIS MORNING WHILE THE SECOND WAVE WAS MOVING EAST ACROSS WYOMING.
THE LEADING TROUGH WILL MOVE ACROSS THE REGION THIS MORNING
KEEPING SHOWERS AND ISOLATED THUNDERSTORMS GOING THROUGH MUCH OF
THE MORNING HOURS. THE TRAILING WAVE WILL ARRIVE EARLY THIS
AFTERNOON...PUSHING ACROSS NORTHERN IOWA THEN INTO SOUTHERN
WISCONSIN BY LATE AFTERNOON INTO THE EARLY EVENING HOURS. THE
FRONT IS EXPECTED TO STALL OUT ACROSS NORTHERN IOWA THROUGH
SOUTHERN WISCONSIN LATE THIS AFTERNOON AND THEN START TO LIFT
NORTH AND ACT AS A WARM FRONT LATE THIS AFTERNOON INTO THIS
EVENING AS VIGOROUS TROUGH DIVES INTO THE NORTHWEST CONUS. AN
INTERESTING ENVIRONMENT SETS UP OVER NORTHEAST IOWA AND FAR
SOUTHWEST WISCONSIN LATE THIS AFTERNOON AS THIS WARM FRONT TAKES
SHAPE. KBLR NAM FORECAST SOUNDINGS SHOW RATHER IMPRESSIVE SHEAR
PROFILES...WITH 0-6 KM BULK SHEAR OF 45 TO 50 KTS...AND 0-1 KM
BULK SHEAR OF 20 TO 25 KTS. CURVATURE ALSO NOTED IN THE HODOGRAPH
FROM THE SURFACE TO 2 KM. THE RAP IS ALSO SHOWING SIMILAR SHEAR
PROFILES. THE NAM IS INDICATING NEARLY 1500 J/KG 0-3KM MUCAPE
VALUES ACROSS THESE AREAS THIS AFTERNOON...BUT THIS IS LIKELY WAY
OVERDONE GIVEN THE NAM IS SHOWING DEWPOINTS CLIMBING TO 60 DEGREES
THIS AFTERNOON. 60 DEGREE DEWPOINTS ARE DISPLACED WAY TO THE
SOUTH...OVER NORTHERN TEXAS. THINKING THE HIGHEST DEWPOINTS THAT
WOULD BE ADVECTED INTO THE AREA WOULD BE IN MID 50S. THE GFS SEEMS
TO BE A LITTLE MORE REALISTIC WITH DEWPOINTS CREEPING INTO THE MID
50S. THINKING THE HIGHEST MUCAPE VALUES WILL BE IN THE 500 TO 800
J/KG RANGE. SOME SURFACE BASED CAPE IS POSSIBLE NEAR THE WARM
FRONT. THE MAJOR LIMITING FACTOR FOR SEVERE THUNDERSTORM POTENTIAL
THIS AFTERNOON IS THE LACK OF MOISTURE/CAPE. THERE MAY BE A BRIEF
WINDOW FOR SEVERE THUNDERSTORMS OVER FAR SOUTHWEST WISCONSIN INTO
NORTHEAST IOWA. PLENTY OF SHEAR FOR SUPERCELLS. THINKING THE MAIN
THREATS WILL BE LARGE HAIL AND DAMAGING WINDS. IF A SURFACE BASED
STORM COULD DEVELOP ALONG THE FRONT...THERE COULD BE A VERY SHORT
WINDOW OF OPPORTUNITY FOR AN ISOLATED TORNADO...BUT IT APPEARS
UNLIKELY AT THIS TIME. WILL HAVE TO KEEP A VERY CLOSE WATCH ALONG
THE WARM FRONT THIS AFTERNOON TO SEE HOW SURFACE DEWPOINTS RESPOND
AS SOUTHERLY FLOW INCREASES INTO THE FRONT. HIGHS TODAY ARE
EXPECTED TO BE A LITTLE COOLER THAN YESTERDAY WITH THE CLOUDS AND
PRECIPITATION OVER THE AREA. PLAN ON HIGHS RANGING FROM THE MID TO
UPPER 60S.
THE WARM FRONT WILL LIFT NORTH ACROSS THE FORECAST AREA TONIGHT
THROUGH EARLY TUESDAY MORNING. 925 MB WARM AIR ADVECTION INCREASES
ACROSS THE FORECAST AREA IN THE WAKE OF THE WARM FRONT...IN THE WARM
SECTOR. DRY AIR ALOFT MOVES IN WITHIN THE WARM SECTOR AND LOOKS TO
EFFECTIVELY CAP THE ENVIRONMENT. HOWEVER...THE NAM IS SUGGESTING
THERE COULD BE ELEVATED CAPE. LIFTING FROM 900 MB YIELDS AROUND 700
J/KG CAPE. DECIDED TO KEEP THE SHOWER AND THUNDERSTORM CHANCES GOING
TONIGHT MAINLY AFTER 06Z. LOWS TONIGHT WILL BE ON THE MILD
SIDE...ESPECIALLY IN THE WAKE OF THE WARM FRONT...WITH LOWS IN THE
MID TO UPPER 50S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 354 AM CDT MON APR 29 2013
THE UPPER TROUGH WILL CONTINUE TO DIG INTO THE CENTRAL CONUS ON
TUESDAY. MEANWHILE...SURFACE LOW PRESSURE IS EXPECTED TO DEEPEN AND
LIFT NORTH ACROSS NORTHERN MINNESOTA AND EVENTUALLY INTO WESTERN
ONTARIO. A COLD FRONT LOOKS TO PUSH SOUTHEAST ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY THROUGH THE DAY ON TUESDAY...WITH SHOWERS
AND THUNDERSTORMS DEVELOPING ALONG THE FRONT MAINLY DURING THE
AFTERNOON HOURS. TEMPERATURES WILL WARM RATHER NICELY AHEAD OF THE
COLD FRONT...WITH HIGHS CLIMBING TO AROUND 80 DEGREES ACROSS
PORTIONS OF NORTHEAST IOWA THROUGH SOUTHWEST WISCONSIN. THE
NAM/GFS/GEM ARE IN FAIRLY DECENT AGREEMENT...SHOWING CONVECTION
DEVELOPING ALONG THE FRONT LATE TUESDAY AFTERNOON INTO TUESDAY
EVENING. THE NAM SEEMS WAY TO AGGRESSIVE WITH ITS DEWPOINTS TUESDAY
AFTERNOON SHOWING SURFACE DEWPOINTS CLIMBING INTO THE MID 60S. MID
TO UPPER 50S SEEM MORE REASONABLE AND THIS IS WHAT IS BEING
ADVERTISED BY THE GEM...WITH 0-3 MUCAPE VALUES AROUND 1500 J/KG. 0-6
KM SHEAR VALUES AROUND 40 KTS WOULD SUPPORT THE POTENTIAL FOR SEVERE
THUNDERSTORMS. PLAN ON SHOWERS AND STORMS ERUPTING ALONG THE FRONT
DURING THE AFTERNOON HOURS. SOME OF THE STORMS MAY BECOME SEVERE
WITH LARGE HAIL AND DAMAGING WINDS THE MAIN THREATS. THE TROUGH
CONTINUES TO DIG TUESDAY NIGHT INTO WEDNESDAY WITH A DEFORMATION
ZONE SETTING UP ACROSS THE UPPER MIDWEST...STRETCHING FROM EASTERN
NEBRASKA NORTHEAST THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION
AND NORTH INTO CENTRAL ONTARIO. A VERY IMPRESSIVE FRONTOGENESIS ZONE
SETS UP ACROSS THE AREA TUESDAY NIGHT AND SITS RIGHT OVER THE
FORECAST AREA WEDNESDAY INTO THURSDAY. LOOKING AT FORECAST MODEL
CROSS SECTIONS RUNNING FROM EAST TO WEST ACROSS THE AREA...A VERY
IMPRESSIVE FRONTOGENESIS ZONE SETS UP OVER THE REGION AND EXTENDS
FROM 875 MB THROUGH 500 MB...WITH NEGATIVE EPV POSITIONED RIGHT OVER
THE FRONTOGENESIS ZONE. THIS ZONE STAYS OVER THE AREA ALL THE WAY
INTO THURSDAY. THIS WILL LEAD TO A PROLONGED PERIOD OF
PRECIPITATION OVER THE AREA WHICH COULD BE MODERATE TO HEAVY AT
TIMES. DRY AND COOL NORTHERLY FLOW INTO THE REGION THEN RAISES THE
QUESTION OF PRECIPITATION TYPE. DEPENDING ON WHICH MODEL SOLUTION
VERIFIES...IT APPEARS THAT THE PRECIPITATION SHOULD FALL AS RAIN
TUESDAY NIGHT AND THROUGH MOST OF THE DAY ON WEDNESDAY THEN SWITCH
OVER TO A RAIN SNOW MIX WEDNESDAY NIGHT INTO EARLY THURSDAY
MORNING. A RAIN SNOW MIX IS POSSIBLE AGAIN THURSDAY NIGHT...THEN
THE PRECIPITATION WILL SWITCH BACK OVER TO ALL RAIN DURING THE DAY
ON FRIDAY AS THE TROUGH CLOSES INTO AN UPPER LOW OVER MISSOURI AND
WARMER AIR FLOWS BACK TO THE NORTH. SNOW ACCUMULATIONS ARE
POSSIBLE LATE WEDNESDAY NIGHT AND AGAIN THURSDAY NIGHT. AT THIS
TIME IT APPEARS A SLUSHY 1-3 INCHES IS POSSIBLE MAINLY ON GRASS
SURFACES. WILL ALSO HAVE TO KEEP A CLOSE EYE ON PRECIPITATION
TYPE...ESPECIALLY THURSDAY NIGHT INTO FRIDAY MORNING AS THE WARM
LAYER SURGES BACK TO THE NORTH. A BRIEF PERIOD OF SLEET IS
POSSIBLE BEFORE TEMPERATURES NEAR THE SURFACE WARM ABOVE FREEZING.
MODEL SOLUTIONS START TO DIVERGE THIS WEEKEND WITH THE HANDLING OF
THE LOW AS IT CUTS OFF. THE GEM TAKES THE LOW INTO THE SOUTHERN
PLAINS...WHILE THE ECMWF LIFTS IT NORTHWEST THROUGH THE DAKOTAS.
THE GFS KEEPS IT STALLED OVER MISSOURI THEN FINALLY LIFTS IT NORTH
INTO THE GREAT LAKES LATE ON SUNDAY. AFTER A COOL PERIOD THURSDAY
AND FRIDAY...WHERE HIGHS WILL ONLY BE IN THE LOWER 40S...SLIGHTLY
WARMER TEMPERATURES ARE POSSIBLE THIS WEEKEND DESPITE CHANCES FOR
RAIN...WITH HIGHS IN THE LOWER TO MIDDLE 50S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1240 PM CDT MON APR 29 2013
A LOW PRESSURE SYSTEM LOCATED OVER EASTERN NEBRASKA WILL MOVE EAST
NORTHEAST ACROSS IOWA THIS AFTERNOON AND EVENING. AT THIS TIME...THE
BEST SHOWER AND THUNDERSTORM THREAT LOOKS TO BE SOUTH OF TAF SITES
ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN. WITH THE LOSS OF
DIURNAL HEATING THIS AFTERNOON...EXPECT THE 2500 TO 5000 CUMULUS
DECK NEAR INTERSTATE 90 TO GRADUALLY DISSIPATE BETWEEN 29.22Z
AND 30.04Z.
AS A COLD FRONT APPROACHES THE AREA ON TUESDAY MORNING...EXPECT A
BROKEN 10 TO 15K FOOT DECK OF CLOUDS TO MOVE INTO KRST AROUND
30.16Z. IN ADDITION AS DIURNAL HEATING OCCURS...EXPECT THE WINDS
TO GUST INTO THE 25 TO 30 KNOT RANGE AT BOTH TAF SITES AFTER
30.15Z.
&&
.HYDROLOGY...
ISSUED AT 354 AM CDT MON APR 29 2013
HEAVY RAINFALL IS POSSIBLE THIS WEEK AS A SYSTEM STALLS OUT
ACROSS THE REGION TOWARD MID WEEK. FORECAST GUIDANCE SUGGESTS
TOTAL RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE POSSIBLE BY THE END OF
THE WEEK. SOME OF THIS PRECIPITATION COULD FALL AS A SLEET/SNOW
MIX. IF THESE RAINFALL AMOUNTS ARE REALIZED...THERE WOULD BE AN
INCREASE IN RIVER LEVELS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION...BOYNE
HYDROLOGY....WETENKAMP