Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/29/12
AREA FORECAST DISCUSSION
NWS DENVER CO
401 PM MDT FRI APR 27 2012
.SHORT TERM...UPPER LOW OVER NORTHERN KANSAS HEADING INTO SOUTHERN
NEBRASKA...WITH ANOTHER UPPER LOW OVER IDAHO AND WESTERN WYOMING.
FAIRLY TIGHT WEST TO NORTHWEST GRADIENT CURRENTLY OVER CFWA WITH
GUSTY WINDS MUCH OF AREA. ALSO SOME LINGERING MOISTURE ACROSS
MOUNTAINS WITH FLOW PRODUCING SOME WEAK OROGRAPHIC SNOW SHOWERS
ALONG CONTINENTAL DIVIDE. MODELS SHOW GRADIENT WEAKENING A BIT
DURING THE EVENING AS PLAINS SYSTEM GRADUALLY MOVES AWAY FROM
AREA. SO WINDS TO BE ON THE DECREASE...THOUGH MAY STILL A BIT
GUSTY OVER THE RIDGES AND FAR EASTERN PLAINS. LATEST RUC KEEPS
SOME MOISTURE IN PLACE OVER THE MOUNTAINS DURING THE EVENING...
WILL KEEP A FEW SHOWERS GOING FOR ZONES 31 AND 34. ON SATURDAY...
UPPER LOW PROGGED TO BE OVER WYOMING THROUGH THE DAY WITH WESTERLY
FLOW ALOFT OVER COLORADO. MODELS HINT AT MID LEVEL SHORTWAVE
ROTATING SOUTHEAST ON BACK SIDE OF THE LOW...WITH SOME INCREASE IN
MID LEVEL MOISTURE AND QG ASCENT OVER CFWA DURING THE AFTERNOON.
AT THE SURFACE...MODELS CONTINUE SHOW RETURN SOUTHERLY FLOW ACROSS
PLAINS BY AFTERNOON WITH SOME INCREASE IN LOW LEVEL MOISTURE. THE
INCREASE IN MOISTURE AND MID LEVEL ASCENT COMBINED WITH MODEST
LAPSE RATES SHOULD BE ENOUGH TO GENERATE SOME SHOWERS ACROSS THE
AREA DURING THE AFTERNOON. WILL MAINTAIN THE SLIGHT CHANCE POPS
FOR NOW AS ASCENT NOT THAT IMPRESSIVE. FORECAST CAPES MINIMAL...SO
NO THUNDER EXPECTED.
.LONG TERM...MODERATE WESTERLY FLOW ALOFT WILL CONTINUE OVER
COLORADO FOR MOST OF THE FORECAST PERIOD AS AN UPPER LOW IS
EXPECTED TO FORM OVER THE NORTHERN PLAINS AND THEN LINGER FOR A
FEW DAYS BEFORE MOVING INTO CANADA. THE LOW AMPLITUDE PATTERN MAY
WELL PERSIST THROUGH THE END OF NEXT WEEK. THIS PATTERN WILL
LIKELY BRING PERIODS OF MID-LEVEL MOISTURE ACROSS THE STATE FROM
THE WEST. THIS WILL KEEP THE CHANCE OF AFTERNOON AND EVENING
SHOWERS OVER THE HIGH COUNTRY. ON THE PLAINS...MSL PRESSURE FIELDS
SHOW THAT SOUTHERLY FLOW ACROSS THE PLAINS IS GOING TO BE FAIRLY
PERSISTENT THROUGH MOST OF THE WEEK. THIS IS GOING TO ALLOW
PERIODIC INTRUSIONS OF GULF MOISTURE ONTO THE EASTERN PLAINS. WEAK
SHORT WAVES EMBEDDED IN THE WESTERLY FLOW ALOFT WILL PROBABLY BE
SUFFICIENT TO GENERATE ROUNDS OF AFTERNOON AND EVENING SHOWER
ACTIVITY ON THE PLAINS EACH DAY. MOS TEMPERATURE GUIDANCE SHOWS
VALUES ON THE PLAINS ABOUT 10 TO 15 DEGREES ABOVE NORMAL THROUGH
THE WEEK. SO WARM TEMPERATURES AND A SLIGHT CHANCE OF SHOWERS WILL
BE THE FORECAST FOR MOST OF THE WEEK.
&&
.AVIATION...FAIRLY TIGHT SURFACE GRADIENT ACROSS PLAINS WITH GUSTY
NORTHWEST WINDS AT AREA AIRPORTS. MODELS SHOW GRADIENT WEAKENING
AFTER 03Z...SHOULD SEE WINDS DECREASE BUT MAY REMAIN NORTHERLY
OVERNIGHT. MODELS SHOW SOUTHEAST WINDS DEVELOPING ACROSS PLAINS
BY 18Z...BUT INDICATE SOME SORT OF DENVER CYCLONE IN THE AREA.
EVENTUAL LOCATION TO AFFECT WIND DIRECTION. WILL KEEP SOME SORT OF
A NORTHERLY COMPONENT FOR NOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
1038 AM MDT FRI APR 27 2012
.UPDATE...STILL SOME LINGERING SHOWERS ACROSS FAR EASTERN
PLAINS...SHOULD BE EXITING THE AREA AS UPPER LOW HEADS EAST INTO
CENTRAL PLAINS. ALSO SOME SNOW SHOWERS OVER HIGHER MOUNTAINS.
THESE TOO SHOULD BE DISSIPATING SHORTLY AS DRIER SUBSIDENT AIR
MOVES OVER AREA. MAIN CONCERN STILL FOR GUSTY WINDS ACROSS PLAINS
AND HIGHER MOUNTAINS THROUGH THE AFTERNOON...THOUGH LATEST MODELS
SHOW GRADIENT DECREASING AS THE AFTERNOON PROGRESSES. EXPECT
SPEEDS TO STAY BELOW HIGH WIND CRITERIA. OVERALL CURRENT FORECASTS
STILL LOOK ON TRACK...MAY NEED TO BEEF THE PLAINS WINDS UP A BIT
FOR A FEW HOURS THIS AFTERNOON.
&&
.AVIATION...NORTHWEST WINDS SLOW TO MATERIALIZE...WITH SURFACE
ANALYSIS SHOWING A BIT OF AN ANTICYCLONE IN THE DENVER AREA. STILL
EXPECT THE NORTHWESTERLIES TO MATERIALIZE BY 18Z. WILL NEED TO
MAKE UPDATES TO DELAY THE GUSTY WINDS. STILL POTENTIAL FOR 25 KT
GUSTS THIS AFTERNOON. OVERALL...CURRENT TAF TRENDS LOOK ON TRACK
WITH VFR CONDITIONS THOUGH LATEST UPDATES TO INCLUDE 5000-6000
FEET CEILINGS FOR A FEW HOURS.
&&
.PREV DISCUSSION... /ISSUED 442 AM MDT FRI APR 27 2012/
SHORT TERM...700-500MB LOW CENTERED JUST SOUTH OF LIMON/SOUTHERN
LINCOLN COUNTY/ AT THIS HOUR ACCORDING TO RUC AND RADAR/SATELLITE
DATA. STRONG ISENTROPIC LIFT ON NORTH-EAST SIDE OF UPPER LOW WITH
A CONVEYOR BELT OF MOISTURE WRAPPING AROUND THE LOW CONTINUES TO
GENERATE NUMEROUS SHOWERS AND SCATTERED T-STORMS OVER MUCH OF
NORTHEAST COLORADO. SMALL STREAM FLOOD ADVISORY WAS ISSUED EARLIER
THIS MORNING FOR MUCH OF LINCOLN COUNTY WITH TRAINING STORMS
DROPPED 2-3 INCHES OF RAIN IN MATTER OF A FEW HOURS ACCORDING TO
RADAR. IN ADDITION HAVE WITNESSED NEW SHOWER/T-STORM DEVELOPMENT
IN THE PAST HOUR ALONG THE FRONT RANGE DUE IN LARGE PART TO A
CONVERGENCE OF DRIER NORTHWESTERLY FLOW OFF THE FRONT RANGE AND
MOIST EASTERLY FLOW ROUNDING THE TOP OF UPPER LOW. ONLY A MATTER
OF TIME FOR THIS NEW BATCH OF SHOWERS TO EITHER MOVE EAST OF THE
AREA OR JUST DISSIPATE WITH THE UPPER LOW CONTINUING TO MOVE EAST-
NORTHEAST AWAY FROM THE FRONT RANGE. HIGH PLAINS AIRMASS HAS
PRETTY BEEN WORK OVER WITH ONLY MARGINAL INSTABILITY SUSTAINING
CONVECTION. WITH THE UPPER LOW EXITING THE STATE MID TO LATE
MORNING...SO SHOULD MOST OF THIS PRECIPITATION...EXCEPT PERHAPS
IN THE FAR NORTHEAST CORNER OF THE STATE AND UP OF THE UPPER
RIDGES ALONG THE CONTINENTAL DIVIDE. CONSEQUENTLY...THE SEVERE
T-STORM WATCH FOR MUCH OF NERN COLORADO HAS BEEN ALLOWED TO
EXPIRE.
ATTENTION TURNS TO THE POSSIBILITY OF STRONG WINDS ON THE PLAINS
AND IN THE FRONT RANGE FOOTHILLS LATER THIS MORNING AND AFTERNOON
AS THE AREA COMES UNDER THE INFLUENCE OF MODERATE SUBSIDENCE AND
INCREASING POST-TROUGH NORTHWESTERLY FLOW ALOFT. CROSS SECTIONS
INDICATE CROSS MTN WIND SPEEDS OVER HIGHER ELEVATIONS OF THE FRONT
RANGE IN THE 40-50KT RANGE MID--MORNING THROUGH MID-AFTERNOON. ON
THE PLAINS...WINDS NOT AS STRONG...BUT NORTHEAST CORNER AND UP
ALONG THE WYOMING BORDER MODELS INDICATE WIND GUSTS IN THE
30-40KT RANGE DURING THE SAME PERIOD. PRESSURE GRADIENT IS
EXPECTED TO QUICKLY RELAX LATE THIS AFTERNOON RESULTING IN A RAPID
DROP OFF IN WIND SPEEDS BEFORE DARK. OTHERWISE AFTER THE SHOWERS
THIS MORNING...SHOULD SEE PLENTY OF SUNSHINE AND MUCH LOWER
HUMIDITY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE. TONIGHT...AREAS
WEST OF THE CONTINENTAL DIVIDE EXPECTED TO SEE A GRADUAL INCREASE
IN MID-LEVEL CLOUD COVER IN RESPONSE TO THE NEXT UPPER AIR TROUGH
TO DROPPING IN FROM THE NORTHWEST.
LONG TERM...THE UPPER LOW WILL REMAIN ANCHORED OVER WYOMING ON
SATURDAY BEFORE LIFTING INTO THE DAKOTAS ON SUNDAY. THIS WILL
LEAVE COLORADO IN A RELATIVELY DRY WESTERLY FLOW THROUGH THE
WEEKEND. HOWEVER THERE WILL BE SOME RETURN LOW LEVEL MOISTURE IN
DEVELOPING SOUTHEAST LOW LVL FLOW ALONG WITH A JET SEGMENT AND
WEAK WAVE LIFTING THROUGH SOUTHEAST COLORADO LATE SATURDAY NIGHT
AND SUNDAY. THIS WILL RESULT IN SOME SCATTERED SHOWER ACTIVITY
ACROSS THE EASTERN PLAINS. MONDAY LOOKS TO BE RATHER DRY EXCEPT
MAYBE A SLIGHT CHANCE OF LATE DAY SHOWERS. THE NEXT WAVE WILL
BRING A BIT OF AN INCREASE IN SHOWERS FOR LATE TUESDAY AND
WEDNESDAY BUT OVERALL MOISTURE AND INSTABILITY IS MARGINAL AND
WILL KEEP POPS IN THE SLIGHT CHANCE RANGE. TEMPERATURES WILL
GRADUALLY WARM TO ABOVE SEASONAL HIGHS BY EARLY NEXT WEEK.
AVIATION...LIFR CEILINGS AND VISIBILITY AT PRESENT TIME AT
DENVER AREA AIRPORTS EXPECTED TO RAPIDLY IMPROVE OVER THE NEXT 1-2
HOURS AS DRIER AIR MOVES DOWN FROM THE FRONT RANGE ON NORTHWEST
WINDS. CIGS AND VSBYS AT BJC SHOULD GO VFR BY 12Z AND NOT LONG
AFTER THAT AT DIA. AFTER THAT TIME...LOOK FOR NORTHWEST WINDS TO
INCREASE DURING THE LATE MORNING HOURS WITH POSSIBLE GUSTS IN THE
20-25KT RANGE BY MIDDAY..POSSIBLY STRONG NEAR THE FOOTHILLS. BY
LATE AFTERNOON...A WEAKENING OF THE PRESSURE GRADIENT WITH THE
UPPER LOW WELL EAST OF COLORADO...EXPECT TO SEE SFC WINDS TURN
NORTH-NORTHEAST FOR A TIME EARLY THIS EVENING BEFORE ASSUMING A
TYPICAL DRAINAGE WIND PATTERN AFTER 03Z. ALL THIS UNDER CLEAR TO
MOSTLY CLEAR SKIES.
HYDROLOGY...PRECIPITATION NEARLY OVER THE FRONT RANGE FOOTHILLS
WITH DRIER DOWNSLOPE FLOW SETTING UP FOR THE REMAINDER OF THE DAY.
COULD STILL SEE A BRIEF SHOWER MOVE OFF THE CONTINENTAL DIVIDE AND
OVER THE FOOTHILLS EARLY THIS MORNING AND DEPOSIT A FEW HUNDREDTHS
OF AN INCH OF RAIN. OTHERWISE NO ADDITIONAL PRECIPITATION
ANTICIPATED FOR THE BURN AREAS ALONG THE FRONT RANGE WITH THIS
STORM SYSTEM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
442 AM MDT FRI APR 27 2012
.SHORT TERM...700-500MB LOW CENTERED JUST SOUTH OF LIMON/SOUTHERN
LINCOLN COUNTY/ AT THIS HOUR ACCORDING TO RUC AND RADAR/SATELLITE
DATA. STRONG ISENTROPIC LIFT ON NORTH-EAST SIDE OF UPPER LOW WITH
A CONVEYOR BELT OF MOISTURE WRAPPING AROUND THE LOW CONTINUES TO
GENERATE NUMEROUS SHOWERS AND SCATTERED T-STORMS OVER MUCH OF
NORTHEAST COLORADO. SMALL STREAM FLOOD ADVISORY WAS ISSUED EARLIER
THIS MORNING FOR MUCH OF LINCOLN COUNTY WITH TRAINING STORMS
DROPPED 2-3 INCHES OF RAIN IN MATTER OF A FEW HOURS ACCORDING TO
RADAR. IN ADDITION HAVE WITNESSED NEW SHOWER/T-STORM DEVELOPMENT
IN THE PAST HOUR ALONG THE FRONT RANGE DUE IN LARGE PART TO A
CONVERGENCE OF DRIER NORTHWESTERLY FLOW OFF THE FRONT RANGE AND
MOIST EASTERLY FLOW ROUNDING THE TOP OF UPPER LOW. ONLY A MATTER
OF TIME FOR THIS NEW BATCH OF SHOWERS TO EITHER MOVE EAST OF THE
AREA OR JUST DISSIPATE WITH THE UPPER LOW CONTINUING TO MOVE EAST-
NORTHEAST AWAY FROM THE FRONT RANGE. HIGH PLAINS AIRMASS HAS
PRETTY BEEN WORK OVER WITH ONLY MARGINAL INSTABILITY SUSTAINING
CONVECTION. WITH THE UPPER LOW EXITING THE STATE MID TO LATE
MORNING...SO SHOULD MOST OF THIS PRECIPITATION...EXCEPT PERHAPS
IN THE FAR NORTHEAST CORNER OF THE STATE AND UP OF THE UPPER
RIDGES ALONG THE CONTINENTAL DIVIDE. CONSEQUENTLY...THE SEVERE
T-STORM WATCH FOR MUCH OF NERN COLORADO HAS BEEN ALLOWED TO
EXPIRE.
ATTENTION TURNS TO THE POSSIBILITY OF STRONG WINDS ON THE PLAINS
AND IN THE FRONT RANGE FOOTHILLS LATER THIS MORNING AND AFTERNOON
AS THE AREA COMES UNDER THE INFLUENCE OF MODERATE SUBSIDENCE AND
INCREASING POST-TROUGH NORTHWESTERLY FLOW ALOFT. CROSS SECTIONS
INDICATE CROSS MTN WIND SPEEDS OVER HIGHER ELEVATIONS OF THE FRONT
RANGE IN THE 40-50KT RANGE MID--MORNING THROUGH MID-AFTERNOON. ON
THE PLAINS...WINDS NOT AS STRONG...BUT NORTHEAST CORNER AND UP
ALONG THE WYOMING BORDER MODELS INDICATE WIND GUSTS IN THE
30-40KT RANGE DURING THE SAME PERIOD. PRESSURE GRADIENT IS
EXPECTED TO QUICKLY RELAX LATE THIS AFTERNOON RESULTING IN A RAPID
DROP OFF IN WIND SPEEDS BEFORE DARK. OTHERWISE AFTER THE SHOWERS
THIS MORNING...SHOULD SEE PLENTY OF SUNSHINE AND MUCH LOWER
HUMIDITY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE. TONIGHT...AREAS
WEST OF THE CONTINENTAL DIVIDE EXPECTED TO SEE A GRADUAL INCREASE
IN MID-LEVEL CLOUD COVER IN RESPONSE TO THE NEXT UPPER AIR TROUGH
TO DROPPING IN FROM THE NORTHWEST.
.LONG TERM...THE UPPER LOW WILL REMAIN ANCHORED OVER WYOMING ON
SATURDAY BEFORE LIFTING INTO THE DAKOTAS ON SUNDAY. THIS WILL
LEAVE COLORADO IN A RELATIVELY DRY WESTERLY FLOW THROUGH THE
WEEKEND. HOWEVER THERE WILL BE SOME RETURN LOW LEVEL MOISTURE IN
DEVELOPING SOUTHEAST LOW LVL FLOW ALONG WITH A JET SEGMENT AND
WEAK WAVE LIFTING THROUGH SOUTHEAST COLORADO LATE SATURDAY NIGHT
AND SUNDAY. THIS WILL RESULT IN SOME SCATTERED SHOWER ACTIVITY
ACROSS THE EASTERN PLAINS. MONDAY LOOKS TO BE RATHER DRY EXCEPT
MAYBE A SLIGHT CHANCE OF LATE DAY SHOWERS. THE NEXT WAVE WILL
BRING A BIT OF AN INCREASE IN SHOWERS FOR LATE TUESDAY AND
WEDNESDAY BUT OVERALL MOISTURE AND INSTABILITY IS MARGINAL AND
WILL KEEP POPS IN THE SLIGHT CHANCE RANGE. TEMPERATURES WILL
GRADUALLY WARM TO ABOVE SEASONAL HIGHS BY EARLY NEXT WEEK.
&&
.AVIATION...LIFR CEILINGS AND VISIBILITY AT PRESENT TIME AT
DENVER AREA AIRPORTS EXPECTED TO RAPIDLY IMPROVE OVER THE NEXT 1-2
HOURS AS DRIER AIR MOVES DOWN FROM THE FRONT RANGE ON NORTHWEST
WINDS. CIGS AND VSBYS AT BJC SHOULD GO VFR BY 12Z AND NOT LONG
AFTER THAT AT DIA. AFTER THAT TIME...LOOK FOR NORTHWEST WINDS TO
INCREASE DURING THE LATE MORNING HOURS WITH POSSIBLE GUSTS IN THE
20-25KT RANGE BY MIDDAY..POSSIBLY STRONG NEAR THE FOOTHILLS. BY
LATE AFTERNOON...A WEAKENING OF THE PRESSURE GRADIENT WITH THE
UPPER LOW WELL EAST OF COLORADO...EXPECT TO SEE SFC WINDS TURN
NORTH-NORTHEAST FOR A TIME EARLY THIS EVENING BEFORE ASSUMING A
TYPICAL DRAINAGE WIND PATTERN AFTER 03Z. ALL THIS UNDER CLEAR TO
MOSTLY CLEAR SKIES.
&&
.HYDROLOGY...PRECIPITATION NEARLY OVER THE FRONT RANGE FOOTHILLS
WITH DRIER DOWNSLOPE FLOW SETTING UP FOR THE REMAINDER OF THE DAY.
COULD STILL SEE A BRIEF SHOWER MOVE OFF THE CONTINENTAL DIVIDE AND
OVER THE FOOTHILLS EARLY THIS MORNING AND DEPOSIT A FEW HUNDREDTHS
OF AN INCH OF RAIN. OTHERWISE NO ADDITIONAL PRECIPITATION
ANTICIPATED FOR THE BURN AREAS ALONG THE FRONT RANGE WITH THIS
STORM SYSTEM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....ENTREKIN
AVIATION...BAKER
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1059 PM MDT THU APR 26 2012
.AVIATION...MOST OF THE HEAVIER TS ACTIVITY HAS MOVED E OF THE I-25
CORRIDOR THIS EVENING. THE TAF SITES COULD SEE BRIEF MVFR
CONDITIONS IN SHRA THRU ABOUT 12Z BEFORE GRADUAL CLEARING OCCURS.
AN ISOLATED TS CANNOT BE RULED OUT THRU ABOUT 09Z...BUT
PROBABILITY IS LOW. TOMORROW...MAIN CONCERN WILL BE GUSTY W
WINDS...WHICH COULD EXCEED 30 KTS AT TIMES AT ALL THE TAF SITES
THROUGH THE DAY. ROSE
&&
.PREV DISCUSSION... /ISSUED 526 PM MDT THU APR 26 2012/
AVIATION...THERE IS APPROXIMATELY A 50 PERCENT CHANCE OF A THUNDERSTORM
AFFECTING THE TAF SITES BETWEEN NOW AND 06Z. WIDELY SCT SHOWERS
AND ISOLD TS CONTINUE TO MOVE FROM THE SW TO NE AT APPROXIMATELY
30 KT. SHOWERS AND TS WILL PRODUCE OCCASIONAL STRONG WIND GUSTS
FROM THE W-SW...WITH GUSTS TO 40-50 KT POSSIBLE. BRIEF IFR-MVR
CONDITIONS ARE POSSIBLE...ALONG WITH SMALL HAIL. STRONGER STORMS
WILL BE POSSIBLE E OF THE I-25 CORRIDOR THIS EVENING. STORMS COULD
CONTINUE TO DEVELOP E AND N OF KPUB-KCOS AS LATE AS 06-09Z.
NOTE THAT WINDS WILL BE QUITE ERRATIC THIS EVENING AT KPUB AND
KCOS...AS LOW LEVEL WINDS ARE FROM THE E-SE WHILE STORMS CONTINUE
TO TRANSFER W-SW WINDS TO THE SURFACE. SO...EVEN AWAY FROM
STORMS...WINDS WILL BE QUITE VARIABLE THIS EVE. 44
PREV DISCUSSION... /ISSUED 205 PM MDT THU APR 26 2012/
SHORT TERM...
(TONIGHT AND FRIDAY)
.MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE POTENTIAL FOR
PORTIONS OF THE SOUTHEAST PLAINS THROUGH THE OVERNIGHT HOURS...
COMPACT CLOSED LOW CIRCULATION ACROSS AZ WILL CONTINUE TO LIFT TO
THE NORTHEAST ACROSS SOUTHERN AND SOUTHEAST COLORADO BETWEEN 06Z AND
12Z. SE SFC WINDS HAVE ADVECTED LOWER 50 DEW POINTS INTO BACA
COUNTY...WITH 40S ALONG THE ARKANSAS RIVER TO THE NORTH.
MEANWHILE...SOUTHWEST WINDS HAVE DROPPED DEW POINTS INTO THE 20S
ACROSS THE HIGH VALLEYS...WITH DEW POINTS DROPPING ACROSS THE NRN
RATON MESA AND PALMER DIVIDE AS DRY LINE TAKES SHAPE. MODELS STILL
PAINT THE SCENARIO OF A COUPLE OF WAVES OF CONVECTION DEVELOPING
ACROSS THE MOUNTAINS AND MOVING OFF INTO THE SOUTHEAST PLAINS.
FIRST WAVE IS CURRENTLY DEVELOPING ACROSS THE MTS NOW...AND EXPECT
CONVECTION TO DEVELOP ALONG THE SFC TROF/DRY LINE BY 20-21Z. SPC
MESO ANALYSIS CURRENTLY SHOWING CAPES OF AROUND 1000 TO NEAR 1500
J/KG ACROSS THE SOUTHEAST PLAINS WITH DEEP LAYER SHEARS RUNNING
AROUND 40-50 KTS. HRRR...RUC13...AND NAM12 MIX THE DEW POINTS OUT
ALONG THE I-25 CORRIDOR BACK INTO THE 30S...THOUGH HANG TOUGH WITH
THE 40S-LOWER 50 DEW POINTS ACROSS THE SOUTHEAST COUNTIES OF
KIOWA...BENT...PROWERS...AND BACA...AS WELL AS EASTERN PORTIONS OF
CROWLEY...OTERO...AND LAS ANIMAS COUNTIES. INITIALLY LCLS WILL START
OUT RATHER HIGH...WITH THE PROXY T/TD SPREADS RUNNING AROUND 30
DEGREES ACROSS THIS REGION. HOWEVER...WITH THE APPROACH OF THE
UPPER TROF...STRENGTHENING SOUTHEASTERLY WINDS WILL ADVECT 40 DEW
POINTS BACK INTO THE NRN I-25 CORRIDOR...WITH 50S TO LOWER 60 DEW
POINTS ACROSS THE SOUTHEAST PLAINS. COUPLED WITH COOLING TEMPS
ALOFT WITH INCOMING SYSTEM...THIS SHOULD AMP UP CAPE VALUES TO
BETWEEN 1500-2500 J/KG...WITH HIGHEST VALUES ACROSS BACA COUNTY BY
06Z. HELICITIES INCREASE TO 500+ M2/S2 BY 06Z WITH FORCING FROM THE
SYSTEM LIKELY TO WEAKEN OR BREAK THROUGH WHATEVER CAP REMAINS.
THUS...SEVERE WEATHER EVENT LOOKS TO START OUT AS A LARGE HAIL...AND
DAMAGING WIND SCENARIO THIS AFTERNOON...AND EVOLVE TO INCLUDE AN
ISOLATED TORNADO POTENTIAL AFTER 9 PM ACROSS THE FAR EASTERN
COUNTIES. THIS ATYPICAL LATE NIGHT TORNADO THREAT FOR THIS REGION
SHOULD LAST UNTIL AROUND 2 AM. STILL THINK THE MAIN THREAT AREA
WILL EXTEND EAST OF A LINE FROM LIMON...TO LA JUNTA...TO KIM.
THOUGH IF RUC IS CORRECT IN SPREADING 40 TO LOWER 50 DEW POINTS BACK
WESTWARD INTO THE I-25 CORRIDOR AFTER THE FIRST ROUND OF AFTERNOON
THUNDERSTORMS...THEN PLENTY OF MOISTURE WILL BE AVAILABLE TO BOOST
CAPES UP FOR THE I-25 CORRIDOR FROM AROUND PUB NORTHWARD FOR THE 2ND
ROUND OF THUNDERSTORMS WHICH SPREADS OFF THE SOUTHEAST MOUNTAINS
DURING THE LATE EVENING. IF THIS OCCURS...THEN HAIL TO NEAR 1 INCH
IN DIAMETER ALONG WITH DAMAGING WINDS MAY BE POSSIBLE FOR KCOS AND
KPUB AS WELL. WILL CONTINUE TO MONITOR THIS POTENTIAL AS SCENARIO
EVOLVES.
ACROSS THE REMAINDER OF THE AREA...WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS AFTERNOON WITH
SNOW LEVELS DROPPING ACROSS THE MOUNTAINS DURING THE EVENING WHEN
BEST FORCING WITH UPPER LEVEL SYSTEM MOVES THROUGH. COULD SEE
ANYWHERE FROM 2 TO 6 INCHES OF SNOW ACROSS THE HIGHER PEAKS...WITH
MAJORITY OF SNOWFALL ABOVE 10KFT.
PRECIPITATION WILL LIFT OFF TO THE NORTHEAST WITH THE PARENT UPPER
LOW ON FRIDAY WITH PRECIPITATION TAILING OFF ACROSS THE
OROGRAPHICALLY FAVORED NORTHWEST FACING SLOPES OF THE SAWATCH AND
MOSQUITOS IN THE MORNING. COULD ALSO SEE A PERIOD OF WRAP AROUND
PCPN ACROSS THE SOUTHEAST PLAINS DURING THE EARLY MORNING...BUT THIS
SHOULD DIMINISH BY AFTERNOON. OTHERWISE...COOLER TEMPERATURES FOR
FRIDAY...THOUGH WITH GUSTY NORTHWEST TO WEST WINDS BEHIND THE
DEPARTING SYSTEM...DEEP MIXING WILL OFFSET THE COOLING ALOFT SOME TO
STILL YIELD TEMPS IN THE 70S. -KT
LONG TERM...
(FRIDAY NIGHT THROUGH THURSDAY)
FRIDAY NIGHT AND SATURDAY NIGHT...CLOSED UPPER LOW OVER NORTHWEST
WYOMING EARLY FRIDAY EVENING MEANDERS INTO THE WESTERN DAKOTAS
THROUGH SATURDAY NIGHT. AT THE SURFACE...UPSLOPE FLOW CONTINUES ON
THE SOUTHEAST CO PLAINS. NAM BREAKS OUT PRECIPITATION ALONG THE
SOUTHEAST MOUNTAINS SATURDAY EVENING...BUT THEN PRECIPITATION AREAS
SHIFT INTO NORTHEAST COLORADO AND FAR SOUTHEASTERN CO. GFS DOESN`T
HAVE MUCH QPF OVER THE MOUNTAINS...BUT HIGHLIGHTS NORTHEAST AND FAR
SOUTHEAST CORNER OF THE STATE LATE SATURDAY EVENING. GIVEN THE
UPSLOPE FLOW...COOL AIR ALOFT AND STEEP LAPSE RATES...KEPT SOME LOW
POPS IN ALONG THE MOUNTAINS AND SPREAD EASTWARD ONTO THE PLAINS
SATURDAY NIGHT. TEMPERATURES SATURDAY SHOULD BE FAIRLY COOL. KEPT
THE PLAINS IN THE MID 50S TO MID 60S FOR HIGHS DESPITE A LARGE
SPREAD IN THE GUIDANCE HIGHS.
SUNDAY AND SUNDAY NIGHT...GFS/ECMWF STILL BULLISH WITH PRECIPITATION
DEVELOPING ACROSS THE SOUTHEAST PLAINS SUNDAY EVENING WITH SHORT
WAVE MOVING ACROSS SOUTHERN COLORADO. NOT AS COOL WITH HIGHS WARMING
INTO THE LOWER 60S TO LOWER 70S ON THE PLAINS.
MONDAY-TUESDAY...GFS/ECMWF BOTH CONTINUE TO SHOW WEST TO
SOUTHWEST FLOW ALOFT OVER COLORADO EARLY IN THE WORK WEEK AHEAD OF
A STRONGER TROF PROGGED TO MOVE THROUGH WY WEDNESDAY. DESPITE
WARMER AND DRIER AIR MOVING INTO THE FORECAST AREA...MODELS SHOW
SOME MID LEVEL MOISTURE AND A FEW WEAK WAVES TRIGGERING
SHOWERS/THUNDERSTORMS OVER THE MOUNTAINS.
WEDNESDAY-THURSDAY...UPPER LEVEL SHORTWAVE TROF MOVES EAST ACROSS WY
WEDNESDAY. AT THE SURFACE...COLD FRONT MOVES SOUTHEAST THROUGH THE
PLAINS WEDNESDAY NIGHT. DRY LOW LEVEL AIRMASS ON THE PLAINS KEEPS SHOWER
ACTIVITY TIED TO THE MOUNTAINS. TROF AXIS SHIFTS EAST INTO THE
PLAINS STATES WITH RIDGE BUILDING OVER CO ON THURSDAY. 40
AVIATION...
A COUPLE OF ROUNDS OF -TSRA MAY AFFECT KCOS AND KPUB TAF SITES...ONE
LATE THIS AFTERNOON...AND ANOTHER DURING THE EVENING AS THE POTENT
UPPER LEVEL STORM SYSTEM MOVES THROUGH THE REGION. FIRST ROUND OF
THUNDERSTORMS WILL PRODUCE ERRATIC GUSTY WINDS UP TO 40 KTS...ALONG
WITH LIGHTNING AND BRIEF HEAVY RAINFALL. THE 2ND ROUND WHICH WILL
SPREAD OFF THE MTNS INTO THE TAF SITES AROUND/AFTER 02Z...COULD BE
STRONGER WITH THE POTENTIAL TO PRODUCE SOME SMALL HAIL UP TO 1 INCH
IN DIAMETER AS WELL AS GUSTY ERRATIC WINDS. THUNDERSTORMS SHOULD
END FOR BOTH KPUB AND KCOS AROUND 06Z WITH NORTH WINDS GUSTING TO 25
TO 30 KTS. BEST WINDOW FOR -TSRA AT KALS WILL BE FROM
01Z-04Z...WITH A ROUND OF GUSTY WINDS...AND LIGHTNING AND BRIEF
MODERATE RAINFALL THE MAIN THREATS. MTN AREAS WILL SEE WIDESPREAD MTN
OBSCURATIONS THROUGH THE EVENING WITH POTENTIAL FOR 2-6 INCHES OF
SNOW DURING THE OVERNIGHT HOURS ACROSS THE HIGHER PEAKS. GUSTY
NORTH TO NW WINDS WILL CONTINUE AT THE TAF SITES THROUGH
FRIDAY...WITH VFR CONDITIONS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
44/10
AREA FORECAST DISCUSSION...CORRECTED
NWS MIAMI FL
900 PM EDT SAT APR 28 2012
.UPDATE...CHALLENGING FORECAST FOR TONIGHT, BUT HERE GOES! RADAR
IMAGERY SHOWS A MID LEVEL LOW JUST NW OF ANDROS. THE LOCAL AREA IS
UNDER THE SUBSIDENCE SIDE OF THIS FEATURE. THIS IS RESULTING IN A
DRY EVENING BUT UNDER AN OVERCAST SKY. HOWEVER, IT STILL LOOKS AS
THOUGH THINGS COULD CHANGE QUICKLY AFTER MIDNIGHT FOR ESPECIALLY
THE SE COAST...BROWARD AND ESPECIALLY MIAMI-DADE. THE REASON
BEING A POTENT SHORTWAVE IS MOVING NORTH TOWARDS SOUTH FLORIDA
AROUND A MID LEVEL LOW JUST NORTH OF THE YUCATAN. TIMING OF THIS
SHORTWAVE IS TO THE SOUTHERN TIP OF THE FL PENINSULA BY 6 AM. DIVERGENCE
WILL INCREASE THROUGHOUT THE NIGHT OUT AHEAD OF THIS VERY
IMPRESSIVE SHORTWAVE, AND AS LOW LEVEL CONVERGENCE INCREASES
ALONG THE ATLANTIC COAST OVERNIGHT DUE TO INCREASING LOW LEVEL
FLOW, THIS COULD RESULT IN QUICK DEVELOPMENT OF SHRA/TSTORMS AFTER
MIDNIGHT. THE HRRR IS BULLISH ON REALLY DEVELOPING CONVECTION
ALONG THE ENTIRE ATLANTIC COAST AT AROUND THE MIDNIGHT TIME AND
CONTINUING THROUGH THE NIGHT. QPF FIELDS OFF BOTH THE GFS/ECMWF
SHOW A HIGH SIGNAL BETWEEN 06-12Z AS WELL...ESPECIALLY OFF THE
MIAMI-DADE COAST.
THERE COULD BE LOCALIZED HEAVY RAIN DEVELOPMENT OVERNIGHT. SHOULD
THIS OCCUR, BELIEVE THE MOST LIKELY LOCALE IS ALONG THE MIAMI-
DADE COAST...BUT CANNOT RULE OUT ANYWHERE ALONG THE ATLANTIC
COAST. DECREASED POPS SUBSTANTIALLY THROUGH MIDNIGHT, THEN HAVE
INCREASING POPS OVERNIGHT FOR THE SOUTH AND EAST COASTS...BUT KEPT
LOW POPS INLAND AND TO THE GREATER NAPLES AREA AS IT LOOKS TO STAY
MOSTLY DRY THERE OVERNIGHT.
SEE PREVIOUS DISCUSSION BELOW FOR FOREAST DETAILS BEYOND TONIGHT.
SHOULD MENTION THOUGH THAT THE LATEST 28.12Z RUN OF THE ECMWF
SHOWS LOW LEVEL WIND FIELDS INCREASING SUN NIGHT-MON...25-30 KT.
THE GFS CONTINUES STRONGER. EITHER WAY, WITH CONVECTION
AROUND...SHOWERS AND THUNDERSTORMS ESPECIALLY FROM SUNDAY NIGHT
THROUGH TUESDAY COULD BE ACCOMPANIED BY NOT ONLY TORRENTIAL RAINS
(LOCALIZED FLOODING CONCERNS ESPECIALLY ATLANTIC COAST), BUT ALSO
A GROWING CONCERN FOR SOME STRONG WIND GUSTS DUE TO CONVECTION IN
A FAST LOW LEVEL FLOW. AS FAR AS THE HEAVY RAIN RISK...IT LOOKS
AS THOUGH THIS RISK MAY CONTINUE EVEN INTO MID WEEK FOR THE EAST
COAST. HOWEVER, HIGHER THAN NORMAL UNCERTAINTY PRECLUDES ANY FLOOD
WATCH ISSUANCE AT THIS TIME. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 738 PM EDT SAT APR 28 2012/
AVIATION...FC TROF XTNDG FM UPR FLA STRAITS NE TO N BAHAMAS.
OVR NXT 24 HRS THIS TROF WL MOV SLOLY W ONTO S FLA WITH A MOIST
EASTERLY WND FLOW PERSISTING ACRS THE AREA. ALG E COAST...VCSH IN
TAFS AFT 09Z BUT WL PLC VCSH IN TAFS AFT 09Z AND AMD IF NEEDED IF
HVY PCPN ACTIVITY DVLPS. MVFR CIGS PSBL IN HVIER RA BUT VFR FOR
MOST PART. WND E 10 TO 15 KTS WITH OCNL HIR GUST BUT WND XPCTD TO
INCRS AFT 09Z WITH PSBL GUSTS > 20 KTS AFT 29/14Z. ATTM NO TSRA
IN TAFS THOUGH ISOLD TSRA PSBL THRU PD. AT KAPF...VFR THRU PD WITH
WND < 10 KTS BUT INCRG AFT 29/14Z 12-14 KTS WITH GUSTS > 20 KTS.
PREV DISCUSSION... /ISSUED 227 PM EDT SAT APR 28 2012/
DISCUSSION...THE DAY IN THE LIFE OF A FORECASTER CAN BE QUITE
TUMULTUOUS AND TODAY IS CERTAINLY NO EXCEPTION. GOING INTO THE
FIRST AND SECOND PERIODS THE MODELS ARE STILL DIVERGING ON HOW TO
HANDLE WHERE THE GREATEST CONVERGENCE AND LIFT WILL BE TO SET UP
CONVECTIVE PRECIPITATION. WATER VAPOR CONTINUES TO SHOW A PLUME OF
RICH TROPICAL MOISTURE FLOWING NORTH ALONG A MID LEVEL TROUGH AXIS
OVER THE WESTERN CARIBBEAN. RADAR SIGNATURES INDICATE THAT AT THE
SFC A CONVERGENT BOUNDARY IS SUGGESTED ALONG THE EXTREME SOUTHERN
TIP OF THE PENINSULA AND EXTENDING INTO THE BAHAMAS. SCT SHRA HAVE
DEVELOPED ALONG THIS BOUNDARY WITH ALSO ISOLD TSRA MAINLY FROM
CENTRAL BROWARD SOUTH ACROSS CENTRAL MIAMI-DADE COUNTIES AND ARE
MOVING WEST IN THE LOW LEVEL EASTERLY FLOW AROUND A SFC RIDGE THAT
STRETCHES ACROSS N FL. SO THIS CONTINUES THE THREAT FOR LATER
DEVELOPMENT ALONG THE COASTAL COLLIER COUNTY REGION THIS
AFTERNOON. BOTH THE NAM AND GFS INITIALIZED QUITE WELL DEPICTING
THIS BOUNDARY AND INTENSIFY THE TROUGH MOVING IT WEST ACROSS S FL
LATE TONIGHT AND SUNDAY THEN INTO THE SOUTHEAST GULF BY SUNDAY
NIGHT WHEREAS THE ECMWF DOES NOT SHOW THE TROUGH. AS THIS TROUGH
DEEPENS AND MOVES WEST, THE NAM DEVELOPS A BAND OF HEAVY
CONVECTION MOVING IT OVER THE SOUTHERN PORTIONS OF THE CWA WITH IN
EXCESS OF TWO INCHES OF RAINFALL BY LATE SUNDAY OVER SOUTHERN
MIAMI-DADE COUNTY WHILE THE GFS KEEPS THE HEAVIEST ACTIVITY
OFFSHORE AS DOES THE ECMWF. ALTHOUGH THE GFS DOES SHOW THE HIGHEST
RAINFALL TOTALS REMAINING OFFSHORE, IT DOES GIVE HIGHER POPS THAN
THE ECMWF WHICH SEEMS REASONABLE GIVEN ITS AGREEMENT TO THE NAM ON
THE SFC TROUGH POSITION. GIVEN ALL OF THIS, WILL LEAN MUCH CLOSER
TO THE NAM AND GFS AS IT MAKES MORE SENSE TO HAVE PLENTY OF
SHRA/TSRA MOVING ONSHORE WITH THE LOW LEVEL EAST WIND FLOW IN
PLACE.
IN ADDITION, WITH THE NAM AND GFS CONTINUING TO SHOW A DEVELOPING
SFC TROUGH THEY BOTH INCREASE THE WIND ACROSS THE LOCAL AREA ON
SUNDAY WITH SCA CONDITIONS OVER THE ATLANTIC WATERS. THIS COULD ALSO
SET UP GOOD COASTAL CONVERGENCE ALONG THE E CST LATE TONIGHT INTO
EARLY SUNDAY FOR POSSIBLE LOCALLY HEAVY RAINFALL IN SOME LOCATIONS
ESPECIALLY FROM EAST CENTRAL BROWARD AND SOUTH ALONG AND NEAR THE
COAST OF MIAMI-DADE COUNTY.
FOR THE EXTENDED, THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK WHEREAS THE ECMWF BUILDS A DEEP LAYER
RIDGE OVER THE ATLANTIC AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
MARINE...MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS
DIVERGING ON THE STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH
ACROSS S FL OVER THE REMAINDER OF WEEKEND. FOR NOW...AM LEANING
TOWARDS A GENERAL EAST WIND INCREASING ON SUNDAY TO AROUND 20
KNOTS OVER THE ATLANTIC WATERS WITH SEAS BUILDING TO POSSIBLY 6
FEET.
FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH PLENTY OF TROPICAL
MOISTURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 81 72 82 / 40 40 50 50
FORT LAUDERDALE 72 80 72 82 / 60 60 50 50
MIAMI 72 81 72 81 / 60 60 50 50
NAPLES 69 83 69 83 / 20 40 30 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
852 PM EDT SAT APR 28 2012
.UPDATE...CHALLENGING FORECAST FOR TONIGHT, BUT HERE GOES! RADAR
IMAGERY SHOWS A MID LEVEL LOW JUST NW OF ANDROW. THE LOCAL AREA IS
UNDER THE SUBSIDENCE SIDE OF THIS FEATURE. THIS IS RESULTING IN A
DRY EVENING BUT UNDER AN OVERCAST SKY. HOWEVER, IT STILL LOOKS AS
THOUGH THINGS COULD CHANGE QUICKLY AFTER MIDNIGHT FOR ESPECIALLY
THE SE COAST...BROWARD AND ESPECIALLY MIAMI-DADE. THE REASON
BEING A POTENT SHORTWAVE IS MOVING NORTH TOWARDS SOUTH FLORIDA
AROUND A MID LEVEL LOW JUST NORTH OF THE YUCATAN. TIMING OF THIS
SHORTWAVE IS TO THE SOUTHERN TIP OF THE FL PENINSULA BY 6 AM. DIVERGENCE
WILL INCREASE THROUGHOUT THE NIGHT OUT AHEAD OF THIS VERY
IMPRESSIVE SHORTWAVE, AND AS LOW LEVEL CONVERGENCE INCREASES
ALONG THE ATLANTIC COAST OVERNIGHT DUE TO INCREASING LOW LEVEL
FLOW, THIS COULD RESULT IN QUICK DEVELOPMENT OF SHRA/TSTORMS AFTER
MIDNIGHT. THE HRRR IS BULLISH ON REALLY DEVELOPING CONVECTION
ALONG THE ENTIRE ATLANTIC COAST AT AROUND THE MIDNIGHT TIME AND
CONTINUING THROUGH THE NIGHT. QPF FIELDS OFF BOTH THE GFS/ECMWF
SHOW A HIGH SIGNAL BETWEEN 06-12Z AS WELL...ESPECIALLY OFF THE
MIAMI-DADE COAST.
THERE COULD BE LOCALIZED HEAVY RAIN DEVELOPMENT OVERNIGHT. SHOULD
THIS OCCUR, BELIEVE THE MOST LIKELY LOCALE IS ALONG THE MIAMI-
DADE COAST...BUT CANNOT RULE OUT ANYWHERE ALONG THE ATLANTIC
COAST. DECREASED POPS SUBSTANTIALLY THROUGH MIDNIGHT, THEN HAVE
INCREASING POPS OVERNIGHT FOR THE SOUTH AND EAST COASTS...BUT KEPT
LOW POPS INLAND AND TO THE GREATER NAPLES AREA AS IT LOOKS TO STAY
MOSTLY DRY THERE OVERNIGHT.
SEE PREVIOUS DISCUSSION BELOW FOR FOREAST DETAILS BEYOND TONIGHT.
SHOULD MENTION THOUGH THAT THE LATEST 28.12Z RUN OF THE ECMWF
SHOWS LOW LEVEL WIND FIELDS INCREASING SUN NIGHT-MON...25-30 KT.
THE GFS CONTINUES STRONGER. EITHER WAY, WITH CONVECTION
AROUND...SHOWERS AND THUNDERSTORMS ESPECIALLY FROM SUNDAY NIGHT
THROUGH TUESDAY COULD BE ACCOMPANIED BY NOT ONLY TORRENTIAL RAINS
(LOCALIZED FLOODING CONCERNS ESPECIALLY ATLANTIC COAST), BUT ALSO
A GROWING CONCERN FOR SOME STRONG WIND GUSTS DUE TO CONVECTION IN
A FAST LOW LEVEL FLOW. AS FAR AS THE HEAVY RAIN RISK...IT LOOKS
AS THOUGH THIS RISK MAY CONTINUE EVEN INTO MID WEEK FOR THE EAST
COAST. HOWEVER, HIGHER THAN NORMAL UNCERTAINTY PRECLUDES ANY FLOOD
WATCH ISSUANCE AT THIS TIME. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 738 PM EDT SAT APR 28 2012/
AVIATION...FC TROF XTNDG FM UPR FLA STRAITS NE TO N BAHAMAS.
OVR NXT 24 HRS THIS TROF WL MOV SLOLY W ONTO S FLA WITH A MOIST
EASTERLY WND FLOW PERSISTING ACRS THE AREA. ALG E COAST...VCSH IN
TAFS AFT 09Z BUT WL PLC VCSH IN TAFS AFT 09Z AND AMD IF NEEDED IF
HVY PCPN ACTIVITY DVLPS. MVFR CIGS PSBL IN HVIER RA BUT VFR FOR
MOST PART. WND E 10 TO 15 KTS WITH OCNL HIR GUST BUT WND XPCTD TO
INCRS AFT 09Z WITH PSBL GUSTS > 20 KTS AFT 29/14Z. ATTM NO TSRA
IN TAFS THOUGH ISOLD TSRA PSBL THRU PD. AT KAPF...VFR THRU PD WITH
WND < 10 KTS BUT INCRG AFT 29/14Z 12-14 KTS WITH GUSTS > 20 KTS.
PREV DISCUSSION... /ISSUED 227 PM EDT SAT APR 28 2012/
DISCUSSION...THE DAY IN THE LIFE OF A FORECASTER CAN BE QUITE
TUMULTUOUS AND TODAY IS CERTAINLY NO EXCEPTION. GOING INTO THE
FIRST AND SECOND PERIODS THE MODELS ARE STILL DIVERGING ON HOW TO
HANDLE WHERE THE GREATEST CONVERGENCE AND LIFT WILL BE TO SET UP
CONVECTIVE PRECIPITATION. WATER VAPOR CONTINUES TO SHOW A PLUME OF
RICH TROPICAL MOISTURE FLOWING NORTH ALONG A MID LEVEL TROUGH AXIS
OVER THE WESTERN CARIBBEAN. RADAR SIGNATURES INDICATE THAT AT THE
SFC A CONVERGENT BOUNDARY IS SUGGESTED ALONG THE EXTREME SOUTHERN
TIP OF THE PENINSULA AND EXTENDING INTO THE BAHAMAS. SCT SHRA HAVE
DEVELOPED ALONG THIS BOUNDARY WITH ALSO ISOLD TSRA MAINLY FROM
CENTRAL BROWARD SOUTH ACROSS CENTRAL MIAMI-DADE COUNTIES AND ARE
MOVING WEST IN THE LOW LEVEL EASTERLY FLOW AROUND A SFC RIDGE THAT
STRETCHES ACROSS N FL. SO THIS CONTINUES THE THREAT FOR LATER
DEVELOPMENT ALONG THE COASTAL COLLIER COUNTY REGION THIS
AFTERNOON. BOTH THE NAM AND GFS INITIALIZED QUITE WELL DEPICTING
THIS BOUNDARY AND INTENSIFY THE TROUGH MOVING IT WEST ACROSS S FL
LATE TONIGHT AND SUNDAY THEN INTO THE SOUTHEAST GULF BY SUNDAY
NIGHT WHEREAS THE ECMWF DOES NOT SHOW THE TROUGH. AS THIS TROUGH
DEEPENS AND MOVES WEST, THE NAM DEVELOPS A BAND OF HEAVY
CONVECTION MOVING IT OVER THE SOUTHERN PORTIONS OF THE CWA WITH IN
EXCESS OF TWO INCHES OF RAINFALL BY LATE SUNDAY OVER SOUTHERN
MIAMI-DADE COUNTY WHILE THE GFS KEEPS THE HEAVIEST ACTIVITY
OFFSHORE AS DOES THE ECMWF. ALTHOUGH THE GFS DOES SHOW THE HIGHEST
RAINFALL TOTALS REMAINING OFFSHORE, IT DOES GIVE HIGHER POPS THAN
THE ECMWF WHICH SEEMS REASONABLE GIVEN ITS AGREEMENT TO THE NAM ON
THE SFC TROUGH POSITION. GIVEN ALL OF THIS, WILL LEAN MUCH CLOSER
TO THE NAM AND GFS AS IT MAKES MORE SENSE TO HAVE PLENTY OF
SHRA/TSRA MOVING ONSHORE WITH THE LOW LEVEL EAST WIND FLOW IN
PLACE.
IN ADDITION, WITH THE NAM AND GFS CONTINUING TO SHOW A DEVELOPING
SFC TROUGH THEY BOTH INCREASE THE WIND ACROSS THE LOCAL AREA ON
SUNDAY WITH SCA CONDITIONS OVER THE ATLANTIC WATERS. THIS COULD ALSO
SET UP GOOD COASTAL CONVERGENCE ALONG THE E CST LATE TONIGHT INTO
EARLY SUNDAY FOR POSSIBLE LOCALLY HEAVY RAINFALL IN SOME LOCATIONS
ESPECIALLY FROM EAST CENTRAL BROWARD AND SOUTH ALONG AND NEAR THE
COAST OF MIAMI-DADE COUNTY.
FOR THE EXTENDED, THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK WHEREAS THE ECMWF BUILDS A DEEP LAYER
RIDGE OVER THE ATLANTIC AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
MARINE...MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS
DIVERGING ON THE STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH
ACROSS S FL OVER THE REMAINDER OF WEEKEND. FOR NOW...AM LEANING
TOWARDS A GENERAL EAST WIND INCREASING ON SUNDAY TO AROUND 20
KNOTS OVER THE ATLANTIC WATERS WITH SEAS BUILDING TO POSSIBLY 6
FEET.
FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH PLENTY OF TROPICAL
MOISTURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 81 72 82 / 40 40 50 50
FORT LAUDERDALE 72 80 72 82 / 60 60 50 50
MIAMI 72 81 72 81 / 60 60 50 50
NAPLES 69 83 69 83 / 20 40 30 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
132 PM EDT FRI APR 27 2012
.AVIATION...
MAINLY VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD.
HIGH PRESSURE WILL CONTINUE TO MOVE OFF TO THE NORTHEAST AND
MOISTURE WILL INCREASE ACROSS THE REGION THROUGH SATURDAY. CLOUDS
WILL BEGIN TO LOWER AND THICKEN TONIGHT AND VCSH WILL BECOME
POSSIBLE AFTER 06Z ESPECIALLY ACROSS THE TERMINALS ALONG AND NEAR
THE SOUTHEAST FLORIDA COAST. WINDS WILL REMAIN EAST ACROSS THE
EAST COAST TERMINALS THIS AFTERNOON AND TONIGHT. AT KAPF A WEST
COAST SEABREEZE WILL DEVELOP LATER THIS AFTERNOON BEFORE
DIMINISHING EARLY THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 1021 AM EDT FRI APR 27 2012/
UPDATE...NO MAJOR CHANGES PLANNED FOR MORNING UPDATES WITH
CURRENT FCST SEEMING TO BE ON TRACK BASED ON CURRENT TRENDS. DEEP
TROPICAL MOISTURE NOT FAR TO OUR SE BUT THIS SHOULD REMAIN
OFFSHORE FOR MOST OF TODAY BEFORE BEING PULLED NORTH OVER THE
WEEKEND. THE 12Z MFL SOUNDING SHOWS VERY DRY CONTINUES ABOVE 5K
BUT THE LOWER LAYERS HAVE MOISTENED WITH PWAT INCREASING TO AN
INCH. THIS MAY BE ENOUGH TO SUPPORT A FEW SHRA LATE THIS AFTERNOON
AND IF FACT THE RAPID REFRESH HAS BEEN CONSISTENT THIS MORNING AND
SHOWING A FEW SHRA DEVELOPING OVER THE FAR SOUTH AND ALONG THE W
CST SEA BREEZE ACROSS INLAND COLLIER COUNTY. SO THAT IS THE ONLY
PLANNED CHANGE TO UP THE POPS TO SLIGHT CHANCE FOR THAT AREA INTO
THE EVENING.
KOB
PREV DISCUSSION... /ISSUED 647 AM EDT FRI APR 27 2012/
AVIATION...12Z ISSUANCE...PREVAILING VFR THROUGH THIS EVENING.
AS A SURFACE HIGH PRESSURE SYSTEM MOVES NORTHEAST AND MOISTURE
BEGINS TO INCREASE IN RESPONSE TO A DEVELOPING TROUGH OVER THE
CARIBBEAN, CLOUDINESS WILL GRADUALLY LOWER AND THICKEN THROUGH
THE PERIOD, ESPECIALLY AFTER 22Z. VCSH WILL ALSO BECOME POSSIBLE
AFTER 06Z, PARTICULARLY ALONG AND NEAR THE SOUTHEAST FLORIDA
COAST. WINDS WILL REMAIN EAST AROUND 10 KNOTS WITH SOME HIGHER
GUSTS, ESPECIALLY AFTER 18Z.
PREV DISCUSSION... /ISSUED 415 AM EDT FRI APR 27 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 82 72 83 / 10 40 30 30
FORT LAUDERDALE 73 83 71 83 / 30 50 50 40
MIAMI 73 82 70 83 / 40 50 50 40
NAPLES 67 87 69 87 / 10 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS MIAMI FL
1021 AM EDT FRI APR 27 2012
.UPDATE...NO MAJOR CHANGES PLANNED FOR MORNING UPDATES WITH
CURRENT FCST SEEMING TO BE ON TRACK BASED ON CURRENT TRENDS. DEEP
TROPICAL MOISTURE NOT FAR TO OUR SE BUT THIS SHOULD REMAIN
OFFSHORE FOR MOST OF TODAY BEFORE BEING PULLED NORTH OVER THE
WEEKEND. THE 12Z MFL SOUNDING SHOWS VERY DRY CONTINUES ABOVE 5K
BUT THE LOWER LAYERS HAVE MOISTENED WITH PWAT INCREASING TO AN
INCH. THIS MAY BE ENOUGH TO SUPPORT A FEW SHRA LATE THIS AFTERNOON
AND IF FACT THE RAPID REFRESH HAS BEEN CONSISTENT THIS MORNING AND
SHOWING A FEW SHRA DEVELOPING OVER THE FAR SOUTH AND ALONG THE W
CST SEA BREEZE ACROSS INLAND COLLIER COUNTY. SO THAT IS THE ONLY
PLANNED CHANGE TO UP THE POPS TO SLIGHT CHANCE FOR THAT AREA INTO
THE EVENING.
KOB
&&
.PREV DISCUSSION... /ISSUED 647 AM EDT FRI APR 27 2012/
AVIATION...12Z ISSUANCE...PREVAILING VFR THROUGH THIS EVENING.
AS A SURFACE HIGH PRESSURE SYSTEM MOVES NORTHEAST AND MOISTURE
BEGINS TO INCREASE IN RESPONSE TO A DEVELOPING TROUGH OVER THE
CARIBBEAN, CLOUDINESS WILL GRADUALLY LOWER AND THICKEN THROUGH
THE PERIOD, ESPECIALLY AFTER 22Z. VCSH WILL ALSO BECOME POSSIBLE
AFTER 06Z, PARTICULARLY ALONG AND NEAR THE SOUTHEAST FLORIDA
COAST. WINDS WILL REMAIN EAST AROUND 10 KNOTS WITH SOME HIGHER
GUSTS, ESPECIALLY AFTER 18Z.
PREV DISCUSSION... /ISSUED 415 AM EDT FRI APR 27 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
.ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 74 82 72 / - 10 40 30
FORT LAUDERDALE 81 73 83 71 / - 30 50 50
MIAMI 82 73 82 70 / 10 40 50 50
NAPLES 86 67 87 69 / - 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
647 AM EDT FRI APR 27 2012
.AVIATION...12Z ISSUANCE...PREVAILING VFR THROUGH THIS EVENING.
AS A SURFACE HIGH PRESSURE SYSTEM MOVES NORTHEAST AND MOISTURE
BEGINS TO INCREASE IN RESPONSE TO A DEVELOPING TROUGH OVER THE
CARIBBEAN, CLOUDINESS WILL GRADUALLY LOWER AND THICKEN THROUGH
THE PERIOD, ESPECIALLY AFTER 22Z. VCSH WILL ALSO BECOME POSSIBLE
AFTER 06Z, PARTICULARLY ALONG AND NEAR THE SOUTHEAST FLORIDA
COAST. WINDS WILL REMAIN EAST AROUND 10 KNOTS WITH SOME HIGHER
GUSTS, ESPECIALLY AFTER 18Z.
&&
.PREV DISCUSSION... /ISSUED 415 AM EDT FRI APR 27 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
..ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 74 82 72 / - 10 40 30
FORT LAUDERDALE 81 73 83 71 / - 30 50 50
MIAMI 82 73 82 70 / 10 40 50 50
NAPLES 86 67 87 69 / - 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION
NWS MIAMI FL
415 AM EDT FRI APR 27 2012
.DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
...ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
&&
.AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
&&
.MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
&&
.FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 74 82 72 / - 10 40 30
FORT LAUDERDALE 81 73 83 71 / - 30 50 50
MIAMI 82 73 82 70 / 10 40 50 50
NAPLES 86 67 87 69 / - 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...14/MJB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
816 PM EDT SAT APR 28 2012
.SYNOPSIS...
A COLD FRONT WILL MEANDER ACROSS THE MIDLANDS TONIGHT THROUGH
SUNDAY. MID AND UPPER LEVEL HIGH PRESSURE RIDGE INTO THE
SOUTHEASTERN STATES WILL HOLD TEMPERATURES ABOVE NORMAL FOR MUCH
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE COLUMBIA AREA ALONG WITH
EXTENSIVE CLOUDINESS. WEAK WEDGE CONTINUES ACROSS THE NORTHERN
MIDLANDS WHERE TEMPERATURES REMAIN IN THE LOWER 60S. RUC MODEL
APPEARS TO HAVE THE BEST HANDLE ON SITUATION WITH DIFFUSE FRONT
ACROSS THE REGION OVERNIGHT AND WEAK NORTHEAST LOW-LEVEL FLOW.
CLOUDINESS WILL LIKELY REMAIN FROM CAE NORTH REDUCING FOG THREAT
IN THE MORNING. DRIER AIR IN THE AGS AREA MAY ALSO HINDER FOG
DEVELOPMENT. SREF KEEPS FOG ACROSS THE COASTAL PLAIN. ADJUSTED
WINDS/TEMPERATURE OVERNIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
THE FRONTAL BOUNDARY MEANDERING ACROSS THE CWA WILL SLOWLY MOVE
NORTHWARD SUNDAY...BUT THEN BEGIN TO DIP ONCE AGAIN SOUTHWARD
SUNDAY NIGHT INTO MONDAY AS MID/UPPER LEVEL RIDING BUILDS ACROSS
THE SOUTHEAST. THE REMNANTS OF FRONTAL BOUNDARY SHOULD FINALLY PUSH
NORTH OF THE CWA OVERNIGHT ON MONDAY NIGHT. MODELS IN GOOD
AGREEMENT THAT MID/UPPER LEVEL RIDGING WILL BUILD ACROSS THE
SOUTHEAST THROUGH THE PERIOD. THIS WILL ALLOW TEMPERATURE TO RISE
EVEN MORE ABOVE NORMAL FOR BOTH SUNDAY. TEMPERATURES WILL BE
SLIGHTLY COOLER ESPECIALLY ACROSS THE NORTHERN CWA AS FRONTAL
BOUNDARY SLIPS BACK SOUTHWARD LATE SUNDAY INTO SUNDAY NIGHT.
TEMPERATURES WILL APPROACH 90 DEGREES IN SOME LOCATIONS SUNDAY.
MODELS AND ENSEMBLES NOT VERY CONFIDENT ON CHANCES FOR RAINFALL
WITH BOUNDARY IN THE VICINITY. MOST POPS REMAIN BELOW 15 PERCENT
THROUGH THE PERIOD. AS FOR LOW TEMPERATURES THROUGH THE
PERIOD...GUIDANCE AND LOCAL NUMBERS REASONABLY CLOSE AND WILL STAY
NEAR CONSENSUS THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE LONG TERM PERIOD WILL BEGIN WITH MID/UPPER LEVEL RIDGING
ACROSS THE SOUTHEAST ON TUESDAY. THIS WILL CONTINUE THROUGH
THURSDAY...WITH A GRADUAL WEAKENING OF THE RIDGE OVER THE REGION
AS IT BEGINS TO SHIFT WESTWARD TOWARD TEXAS BY FRIDAY/SATURDAY. AT
THE SURFACE...HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL RIDGE
INTO SOUTH CAROLINA AND GEORGIA THROUGH THURSDAY. RIDGING ACROSS
THE AREA WILL ALLOW TEMPERATURES TO REMAIN WELL ABOVE NORMAL
THROUGH THE PERIOD. EXPECT MIDDLE TO UPPER 80S...MAYBE EVEN A FEW
TEMPERATURES AROUND 90 THROUGH THE PERIOD. BY FRIDAY AND
SATURDAY...H5 HEIGHTS BEGIN TO LOWER ACROSS THE REGION AND HIGH
PRESSURE SETTLES FARTHER SOUTH AND EAST. BOTH ECMWF/GFS INDICATE A
WEAK FRONT MOVING ACROSS THE AREA FRIDAY NIGHT. THIS WILL ALLOW
FOR SOME SLIGHTLY COOLER TEMPERATURES FOR THE END OF THE EXTENDED
PERIOD. MUCH OF THE EXTENDED PERIOD LOOKS DRY. BUT CANNOT RULE OUT
AN ISOLATED AFTERNOON SHOWER OR STORM THROUGH THE ENTIRE WEEK.
HAVE INCLUDED A SLIGHT CHANCE FOR A SHRA/TSRA FRIDAY/FRIDAY NIGHT
FOR THE NORTHWEST PORTION OF THE CWA.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
COLD FRONTAL
BOUNDARY IS MOVING BACK TO THE SOUTHWEST WITH LOW STRATOCU DECK
DEVELOPING BEHIND THE FRONT. MVFR CIGS AND VSBYS EXPECTED BEHIND
THE FRONT WITH LOCAL IFR CIGS BETWEEN MIDNIGHT AND 14Z SUNDAY
MORNING. DO NOT EXPECT THE FRONT TO MAKE IT TO THE SAVANNAH RIVER
AND IT SHOULD MOVE NE OUT OF THE AREA BY NOON SUNDAY WITH CIGS AND
VSBYS IMPROVING TO VFR. POTENTIAL FOR MVFR VSBYS AGAIN SUNDAY NIGHT.
EXTENDED AVIATION OUTLOOK MONDAY THROUGH THURSDAY...NO SIGNIFICANT
IMPACTS TO AVIATION EXPECTED MONDAY THROUGH THURSDAY OUTSIDE OF
POSSIBLE ISOLATED CONVECTION.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...77
LONG TERM...77
AVIATION...
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
128 PM EDT FRI APR 27 2012
.UPDATE...
/ISSUED AT 1021 AM EDT FRI APR 27 2012/
WEAK FRONT IN NORTH GEORGIA...SAGGING TOWARDS ATLANTA AREA...
INCREASING CLOUDS TODAY. FORECAST ON TRACK...SLIGHT TWEAKS TO
CLOUDS/SKY...TEMPERATURES...AND WINDS FOR TODAY BASED OFF CURRENTLY
OBSERVED TRENDS. THE FRONT...CURRENTLY EXTENDING FROM ABOUT
DAHLONEGA TO ROME...COULD SPARK SOME SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING AS IT CREEPS SOUTHWARD.
10/39
&&
.PREV DISCUSSION... /ISSUED 745 AM EDT FRI APR 27 2012/
SHORT TERM /TODAY THROUGH SATURDAY/...
WEAK NORTHWESTERLY FLOW ALOFT HELPED A WEAK SURFACE COLD FRONT
MOVE TO THE NORTHERN DOORSTEP OF GEORGIA...AND STALL THERE. THIS
WILL SERVE AS A FOCUS FOR AFTERNOON CONVECTION THIS AFTERNOON...
ALTHOUGH THERE IS GREAT MODEL DISPARITY REGARDING THE AREAL
COVERAGE AND ACCUMULATION. NAM AND SREF ARE FAR MORE AGGRESSIVE
WITH LATE AFTERNOON THUNDERSTORMS FOR NORTH GEORGIA...BUT
ECMWF...GFS AND HRRR HAVE FAR LESS COVERAGE AND LIGHTER
ACCUMULATIONS. WILL SIDE WITH THE LESS AGGRESSIVE SOLUTIONS FOR
NOW...BUT THIS WILL NEED TO BE WATCHED. EXPECTING WIDESPREAD
MORNING STRATUS WHICH WILL INHIBIT HEATING...SO LATER CONVECTIVE
INITIATION SEEMS REASONABLE. CENTRAL GEORGIA LOOKS LIKE IT WILL
ESCAPE THE PRECIP CHANCES FOR THE SHORT-TERM. MOS TEMPS LOOK
GOOD...SO WILL NOT STRAY FROM GUIDANCE.
27
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED BEGINS WITH RIDGING BUILDING IN ALOFT AND SURFACE HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGING INTO THE SOUTHEAST. THE
MAIN FLOW...ALONG WITH WEAK EMBEDDED IMPULSES...REMAINS JUST TO OUR
NORTH ROUNDING THE TOP OF THE RIDGE. WITH INCREASING THICKNESSES
AND MOISTURE...THE GFS REALLY INCREASES TEMPS ON SUNDAY...
FORECASTING RECORD OR NEAR-RECORD HIGHS IN THE UPPER 80S AND LOWER
90S. THE NAM HOWEVER REMAINS 8-10 DEGREES COOLER AND IS SIMPLY NOT
AS STRONG WITH THE RIDGING ALOFT. THE ECMWF SEEMS TO SUPPORT THE
GFS/S SOLUTION...SO OVERALL HAVE TAKEN A BLEND TO AVOID A DRAMATIC
SWING FROM YESTERDAY/S FORECAST BUT HAVE LEANED TOWARD THE WARMER
GFS. THIS WARMING TREND CONTINUES INTO THE EARLY PART OF THE WEEK
WITH THE 00Z GFS MUCH WARMER THAN THE 12Z RUN YESTERDAY...AND
WARMER THAN THE ECMWF IS IMPLYING. HAVE AGAIN TAKEN A BLEND...
TRYING TO ACCOUNT FOR RUN-TO-RUN DIFFERENCES AND FACTORING IN THE
ECMWF SOLUTION. OVERALL THOUGH TEMPS REMAIN ABOVE NORMAL THROUGH
THE PERIOD.
AS FOR POPS...THE EXTENDED LOOKS MOSTLY DRY...THOUGH AS THE UPPER
RIDGE BEGINS TO BREAK DOWN BY MONDAY NIGHT MOISTURE WILL BE ABLE
TO WORK FIRST INTO NORTH GEORGIA AND THEN FURTHER SOUTH. POPS
REMAIN SLIGHT CHANCE AT BEST BUT WITH A TYPICAL SUMMERLIKE DIURNAL
TREND TO THE CONVECTIVE POTENTIAL. BOTH THE GFS AND ECMWF WANT TO
BRING MOISTURE FROM THE ATLANTIC OVER FLORIDA AND EVENTUALLY INTO
PARTS OF GEORGIA...WITH THE GFS FASTER AND MORE IMPRESSIVE WITH
THE MOISTURE AMOUNTS. OF COURSE...THE GFS IS LIKELY OVERDONE WITH
THIS BUT THE TRENDS WILL HAVE TO BE MONITORED THROUGH SUBSEQUENT
FORECASTS.
TDP
&&
.AVIATION...
18Z UPDATE...
WEAK FRONTAL BOUNDARY ACROSS NORTH GA WILL PROVIDE THE FOCUS FOR
SCATTERED AFTERNOON CONVECTION. THE FRONT AND ASSOCIATED CONVECTION
IS EXPECTED TO SAG SOUTH THROUGH THE AFTERNOON... WARRANTING A TEMPO
TSRA GROUP FOR ATLANTA AREA TAF SITES FROM 20-23Z. THE SHRA/TSRA
THREAT SHOULD PUSH EAST OF ATL BY 00Z SAT WITH SCT MID CLOUDS ON TAP
OVERNIGHT. MAY SEE SCT-BKN LOW CLOUDS (900 TO 1200 FEET) CREEP NORTH
TOWARD ATL BY 12-13Z SAT MORN...BUT MODELS DO NOT INDICATE THIS SO
WILL JUST MENTION SCT FOR NOW. INCREASED RIDGING ALOFT WILL WARRANT
NO MENTION OF CONVECTION ON SAT. SW WINDS 8-10KTS THIS AFTERNOON
WILL GO LIGHT AND MORE SOUTHERLY TONIGHT. SW WINDS 8-10KTS WILL
PREVAIL ON SAT.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...EXCEPT MODERATE CONFIDENCE ON
AFTERNOON TSRA COVERAGE IN ATL AREA.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 83 59 85 60 / 40 20 10 5
ATLANTA 81 62 84 63 / 30 10 10 5
BLAIRSVILLE 78 55 81 54 / 20 20 10 10
CARTERSVILLE 79 58 87 57 / 30 20 20 10
COLUMBUS 84 61 86 60 / 5 10 5 5
GAINESVILLE 81 61 85 61 / 40 20 10 10
MACON 85 58 86 58 / 20 5 5 5
ROME 83 59 87 58 / 30 20 20 10
PEACHTREE CITY 82 56 87 56 / 20 10 10 5
VIDALIA 86 64 88 64 / 10 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
745 AM EDT FRI APR 27 2012
.SHORT TERM /TODAY THROUGH SATURDAY/...
WEAK NORTHWESTERLY FLOW ALOFT HELPED A WEAK SURFACE COLD FRONT
MOVE TO THE NORTHERN DOORSTEP OF GEORGIA...AND STALL THERE. THIS
WILL SERVE AS A FOCUS FOR AFTERNOON CONVECTION THIS AFTERNOON...
ALTHOUGH THERE IS GREAT MODEL DISPARITY REGARDING THE AREAL
COVERAGE AND ACCUMULATION. NAM AND SREF ARE FAR MORE AGGRESSIVE
WITH LATE AFTERNOON THUNDERSTORMS FOR NORTH GEORGIA...BUT
ECMWF...GFS AND HRRR HAVE FAR LESS COVERAGE AND LIGHTER
ACCUMULATIONS. WILL SIDE WITH THE LESS AGGRESSIVE SOLUTIONS FOR
NOW...BUT THIS WILL NEED TO BE WATCHED. EXPECTING WIDESPREAD
MORNING STRATUS WHICH WILL INHIBIT HEATING...SO LATER CONVECTIVE
INITIATION SEEMS REASONABLE. CENTRAL GEORGIA LOOKS LIKE IT WILL
ESCAPE THE PRECIP CHANCES FOR THE SHORT-TERM. MOS TEMPS LOOK
GOOD...SO WILL NOT STRAY FROM GUIDANCE.
27
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED BEGINS WITH RIDGING BUILDING IN ALOFT AND SURFACE HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGING INTO THE SOUTHEAST. THE
MAIN FLOW...ALONG WITH WEAK EMBEDDED IMPULSES...REMAINS JUST TO OUR
NORTH ROUNDING THE TOP OF THE RIDGE. WITH INCREASING THICKNESSES
AND MOISTURE...THE GFS REALLY INCREASES TEMPS ON SUNDAY...
FORECASTING RECORD OR NEAR-RECORD HIGHS IN THE UPPER 80S AND LOWER
90S. THE NAM HOWEVER REMAINS 8-10 DEGREES COOLER AND IS SIMPLY NOT
AS STRONG WITH THE RIDGING ALOFT. THE ECMWF SEEMS TO SUPPORT THE
GFS/S SOLUTION...SO OVERALL HAVE TAKEN A BLEND TO AVOID A DRAMATIC
SWING FROM YESTERDAY/S FORECAST BUT HAVE LEANED TOWARD THE WARMER
GFS. THIS WARMING TREND CONTINUES INTO THE EARLY PART OF THE WEEK
WITH THE 00Z GFS MUCH WARMER THAN THE 12Z RUN YESTERDAY...AND
WARMER THAN THE ECMWF IS IMPLYING. HAVE AGAIN TAKEN A BLEND...
TRYING TO ACCOUNT FOR RUN-TO-RUN DIFFERENCES AND FACTORING IN THE
ECMWF SOLUTION. OVERALL THOUGH TEMPS REMAIN ABOVE NORMAL THROUGH
THE PERIOD.
AS FOR POPS...THE EXTENDED LOOKS MOSTLY DRY...THOUGH AS THE UPPER
RIDGE BEGINS TO BREAK DOWN BY MONDAY NIGHT MOISTURE WILL BE ABLE
TO WORK FIRST INTO NORTH GEORGIA AND THEN FURTHER SOUTH. POPS
REMAIN SLIGHT CHANCE AT BEST BUT WITH A TYPICAL SUMMERLIKE DIURNAL
TREND TO THE CONVECTIVE POTENTIAL. BOTH THE GFS AND ECMWF WANT TO
BRING MOISTURE FROM THE ATLANTIC OVER FLORIDA AND EVENTUALLY INTO
PARTS OF GEORGIA...WITH THE GFS FASTER AND MORE IMPRESSIVE WITH
THE MOISTURE AMOUNTS. OF COURSE...THE GFS IS LIKELY OVERDONE WITH
THIS BUT THE TRENDS WILL HAVE TO BE MONITORED THROUGH SUBSEQUENT
FORECASTS.
TDP
&&
.AVIATION...
12Z UPDATE...
MORNING MVFR CIGS WILL REMAIN CONFINED TO SOUTHERN TAF SITES /CSG
AND MCN/. AREAL COVERAGE OF AFTERNOON CONVECTION REMAINS THE
QUESTION...BUT NAM...GFS...AND WRF COMING INTO AGREEMENT WITH MORE
COVERAGE. RAISED TSRA CHANCES TO TEMPO IN NORTHERN GEORGIA
TAFS...BUT TIMING WILL BE EARLY AFTERNOON. LIGHT WEST WINDS FOR THE
DURATION OF THE PERIOD. MORNING STRATUS AGAIN SATURDAY...BUT WILL
NOT BITE ON CIGS AT THIS POINT.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...WITH MODERATE CONFIDENCE ON
AFTERNOON TSRA COVERAGE.
27
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 83 59 85 60 / 40 20 10 5
ATLANTA 80 62 84 63 / 30 10 10 5
BLAIRSVILLE 78 55 81 54 / 20 20 10 10
CARTERSVILLE 79 58 87 57 / 30 20 20 10
COLUMBUS 84 61 86 60 / 5 10 5 5
GAINESVILLE 81 61 85 61 / 40 20 10 10
MACON 85 58 86 58 / 20 5 5 5
ROME 83 59 87 58 / 30 20 20 10
PEACHTREE CITY 81 56 87 56 / 20 10 10 5
VIDALIA 86 64 88 64 / 10 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
336 AM EDT FRI APR 27 2012
.SHORT TERM /TODAY THROUGH SATURDAY/...
WEAK NORTHWESTERLY FLOW ALOFT HELPED A WEAK SURFACE COLD FRONT
MOVE TO THE NORTHERN DOORSTEP OF GEORGIA...AND STALL THERE. THIS
WILL SERVE AS A FOCUS FOR AFTERNOON CONVECTION THIS AFTERNOON...
ALTHOUGH THERE IS GREAT MODEL DISPARITY REGARDING THE AREAL
COVERAGE AND ACCUMULATION. NAM AND SREF ARE FAR MORE AGGRESSIVE
WITH LATE AFTERNOON THUNDERSTORMS FOR NORTH GEORGIA...BUT
ECMWF...GFS AND HRRR HAVE FAR LESS COVERAGE AND LIGHTER
ACCUMULATIONS. WILL SIDE WITH THE LESS AGGRESSIVE SOLUTIONS FOR
NOW...BUT THIS WILL NEED TO BE WATCHED. EXPECTING WIDESPREAD
MORNING STRATUS WHICH WILL INHIBIT HEATING...SO LATER CONVECTIVE
INITIATION SEEMS REASONABLE. CENTRAL GEORGIA LOOKS LIKE IT WILL
ESCAPE THE PRECIP CHANCES FOR THE SHORT-TERM. MOS TEMPS LOOK
GOOD...SO WILL NOT STRAY FROM GUIDANCE.
27
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED BEGINS WITH RIDGING BUILDING IN ALOFT AND SURFACE HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGING INTO THE SOUTHEAST. THE
MAIN FLOW...ALONG WITH WEAK EMBEDDED IMPULSES...REMAINS JUST TO OUR
NORTH ROUNDING THE TOP OF THE RIDGE. WITH INCREASING THICKNESSES
AND MOISTURE...THE GFS REALLY INCREASES TEMPS ON SUNDAY...
FORECASTING RECORD OR NEAR-RECORD HIGHS IN THE UPPER 80S AND LOWER
90S. THE NAM HOWEVER REMAINS 8-10 DEGREES COOLER AND IS SIMPLY NOT
AS STRONG WITH THE RIDGING ALOFT. THE ECMWF SEEMS TO SUPPORT THE
GFS/S SOLUTION...SO OVERALL HAVE TAKEN A BLEND TO AVOID A DRAMATIC
SWING FROM YESTERDAY/S FORECAST BUT HAVE LEANED TOWARD THE WARMER
GFS. THIS WARMING TREND CONTINUES INTO THE EARLY PART OF THE WEEK
WITH THE 00Z GFS MUCH WARMER THAN THE 12Z RUN YESTERDAY...AND
WARMER THAN THE ECMWF IS IMPLYING. HAVE AGAIN TAKEN A BLEND...
TRYING TO ACCOUNT FOR RUN-TO-RUN DIFFERENCES AND FACTORING IN THE
ECMWF SOLUTION. OVERALL THOUGH TEMPS REMAIN ABOVE NORMAL THROUGH
THE PERIOD.
AS FOR POPS...THE EXTENDED LOOKS MOSTLY DRY...THOUGH AS THE UPPER
RIDGE BEGINS TO BREAK DOWN BY MONDAY NIGHT MOISTURE WILL BE ABLE
TO WORK FIRST INTO NORTH GEORGIA AND THEN FURTHER SOUTH. POPS
REMAIN SLIGHT CHANCE AT BEST BUT WITH A TYPICAL SUMMERLIKE DIURNAL
TREND TO THE CONVECTIVE POTENTIAL. BOTH THE GFS AND ECMWF WANT TO
BRING MOISTURE FROM THE ATLANTIC OVER FLORIDA AND EVENTUALLY INTO
PARTS OF GEORGIA...WITH THE GFS FASTER AND MORE IMPRESSIVE WITH
THE MOISTURE AMOUNTS. OF COURSE...THE GFS IS LIKELY OVERDONE WITH
THIS BUT THE TRENDS WILL HAVE TO BE MONITORED THROUGH SUBSEQUENT
FORECASTS.
TDP
&&
.AVIATION...
06Z UPDATE...
WIDELY SCATTERED SHOWERS WILL TRICKLE ACROSS FAR NORTH GA THROUGH
THE EARLY MORNING BUT NOT EXPECTED TO IMPACT TAF SITES. MORNING MVFR
CIGS LIKELY ACROSS MOST SITES AND WILL QUICKLY LIFT BY 15Z.
AFTERNOON CONVECTION A CONCERN...BUT AREAL COVERAGE APPEARS LIMITED
PER ALL MODELS EXCEPT NAM SO WILL NOT MENTION IN TAFS AT THIS TIME.
MAY AUGMENT THIS AT 12Z. LIGHT WEST WINDS FOR THE DURATION OF THE
PERIOD.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...WITH MODERATE CONFIDENCE ON
AFTERNOON TSRA COVERAGE.
27
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 83 59 85 60 / 40 20 10 5
ATLANTA 80 62 84 63 / 30 10 10 5
BLAIRSVILLE 78 55 81 54 / 20 20 10 10
CARTERSVILLE 79 58 87 57 / 30 20 20 10
COLUMBUS 84 61 86 60 / 5 10 5 5
GAINESVILLE 81 61 85 61 / 40 20 10 10
MACON 85 58 86 58 / 20 5 5 5
ROME 83 59 87 58 / 30 20 20 10
PEACHTREE CITY 81 56 87 56 / 20 10 10 5
VIDALIA 86 64 88 64 / 10 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
702 PM CDT SAT APR 28 2012
.AVIATION...
VERY CHALLENGING CLOUD FCST IN THE SHORT TERM. LOW CLOUDS CONTINUE
DISSIPATING IN A BAND FROM NORTHEAST IA THROUGH NORTHERN IL
LIKELY DUE MOSTLY TO SUBSIDENCE. RUC BACKUP MODEL ONLY GUIDANCE
THAT IS HANDLING THIS CLEARING TREND ALTHOUGH IT IS TOO FAST...
BUT FOLLOWED FOR TRENDS AND HAVE GENERALLY BROUGHT CIGS UP TO VFR
AT ALL SITES FOR A TIME TNGT. ANOTHER FAIRLY LARGE AREA OF LOW
CLOUDS WITH MAINLY MVFR CIGS EXTENDS FROM WI INTO NORTHEAST IL AND
AS THE LOW LEVEL FLOW SHIFTS MORE NELY LATER TNGT MAY SEE THESE
CLOUDS WORK BACK IN OVER THE TERMINALS. OVRNGT AND EARLY SUN AM WILL
SEE SCT SHRA MOVE IN AHEAD OF NEXT SYSTEM. PCPN TO BECOME MORE
WIDESPREAD BY LATE AM AND THROUGH THE AFTN WHILE LIFTING ACROSS THE
TERMINALS. EXPECT MAINLY RAIN WITH FEW EMBEDDED TSRA POSSIBLE... WITH
CONDITIONS LOWERING INTO MVFR AND IFR CATEGORIES. WINDS GENERALLY
TO MAINTAIN AN EASTERLY COMPONENT NEXT 24 HRS VARYING FROM NE TO
SE AT 10-20 KTS AND GUSTY.
&&
.PREV DISCUSSION... /ISSUED 254 PM CDT SAT APR 28 2012/
SYNOPSIS...
HIGHLY AMPLIFIED FLOW WAS IN PLACE OVER THE NORTHERN U.S. THIS
MORNING. A DEEP TROF WITH A CLOSED LOW AT 500MB WAS LOCATED OVER
THE WESTERN U.S. WITH SHARP DOWNSTREAM RIDGING FROM THE WESTERN
GREAT LAKES THROUGH MANITOBA. OVER THE SOUTHERN U.S. A MUCH FLATTER
FLOW REGIME WAS IN PLACE WITH BROAD UPPER TROUGHING IN THE WEST
LEADING INTO A FLAT RIDGE OVER THE SOUTHEASTERN U.S. AND THE WESTERN
ATLANTIC. AT THE SURFACE AN OCCLUDED/DECAYING SURFACE LOW WAS OVER
THE NORTHERN PLAINS WITH A TROF EXTENDING SOUTHEAST INTO THE MO
RIVER VALLEY. HIGH PRESSURE WAS LOCATED FROM ONTARIO INTO THE GREAT
LAKES. TO THE SOUTH A NEARLY STATIONARY FRONT EXTENDED FROM THE
SOUTHERN PLAINS INTO CENTRAL MO AND IL. NORTHEASTERLY FLOW BETWEEN
THE GREAT LAKES HIGH THE NORTHERN PLAINS LOW WAS KEEPING COOL
TEMPERATURES IN PLACE TODAY AS WELL AS WIDESPREAD CLOUDS. TSRA HAD
DEVELOPED OVER MO NEAR THE STALLED FRONT EARLY THIS AFTERNOON WITH
SOME SCATTERED ELEVATED SHRA FURTHER NORTH EXTENDING INTO SOUTHEAST
IA AND WEST CENTRAL IL.
SHORT TERM...TONIGHT AND SUNDAY...
THE MAIN FOCUS WILL BE PRECIPITATION CHANCES THROUGH THE PERIOD. THE
NORTHERN PLAINS UPPER/SURFACE LOWS WILL LIFT NORTHEAST INTO CANADA
AND THE HIGH OVER THE GREAT LAKES WILL SHIFT EAST BY SUNDAY. THE FRONT TO
THE SOUTH THOUGH WILL REMAINED ALIGNED WITH THE UPPER SOUTHWEST FLOW
AND WILL MOVE LITTLE THROUGH SUNDAY AFTERNOON. VARIOUS MODEL
SOLUTIONS SHOW S/W/S EJECTING OUT OF THE SWRN U.S. TROF TONIGHT AND
SUNDAY WITH LOW LEVEL...850MB...FLOW INCREASING FROM THE SOUTHWEST
AHEAD OF THE WAVES. THIS WILL ENHANCE LOW LEVEL WARM/MOIST
ADVECTION NORTH OF THE SURFACE FRONT...INTO SOUTHERN IA AND NORTHERN
MO. THE ADVECTION IS WEAK AS IT ENTERS THE CWFA TONIGHT BUT MODELS
ARE SHOWING SOME LOW CAPES...LESS THAN 500 J/KG. MODELS ALSO SHOW AN
H250 JET STREAK APPROACHING LATE TONIGHT WHICH MAY PROVIDE SOME
UPPER SUPPORT SO HAVE INCLUDED SOME CHANCE POPS SOUTH TONIGHT FOR
MAINLY SHRA BUT SOME ISOLATED T POSSIBLE NEAR THE IA/MO BORDER.
EXPECT LOTS OF CLOUDS TONIGHT AND PERSISTENT EASTERLY SURFACE FLOW
WHICH WILL KEEP TEMPERATURES ON THE COLD SIDE. GFS MOS GUIDANCE WITH
MID 30S NORTHEAST TO UPPER 40S SOUTH LOOKS REASONABLE FOR TONIGHTS
MINS.
FOR SUNDAY MODELS SHOW ANOTHER WAVE/JET STREAK LIFTING OUT OF THE
SOUTHWEST U.S. INTO WESTERN IA BY LATE SUNDAY AFTERNOON. THIS SHOULD
PROVIDE GOOD SUPPORT FOR SHRA OVER THE AREA. SPREAD POPS NORTH
ACROSS THE CWFA DURING THE DAY WITH THE HIGHEST POPS IN THE LIKELY
CATEGORY OVER THE WESTERN COUNTIES DURING THE AFTERNOON. AGAIN
CAPES WILL BE LOW...AND LIMITED AND THUNDER MENTION TO THE SOUTH
WHERE CAPES ARE 100-500 J/KG. LOW LEVEL FLOW SHOULD BE MORE
SOUTHEASTERLY SUNDAY WHICH SHOULD ALLOW TEMPERATURES TO WARM A
LITTLE MORE THAN TODAY...SO WENT WITH HIGHS IN THE 50S TO LOW 60S.
DLF
LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...
FORECAST FOCUS ON THUNDERSTORM CHANCES NEARLY EVERY DAY AS FRONT
MEANDERS NORTH/SOUTH ACROSS THE REGION.
SUNDAY NIGHT INTO MONDAY...SIGNIFICANT WAVE APPROACHES THE AREA AS
WARM FRONT LIFTS INTO THE CWA FOLLOWED BY COLD FRONT ON MONDAY.
WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED SUNDAY NIGHT GRADUALLY
ENDING ON MONDAY MORNING. PRECIPITABLE WATERS INCREASE TO NEARLY
1.50 INCHES WHICH WOULD SUPPORT AT LEAST AN INCH OF RAIN AT MANY
LOCATIONS.
TUESDAY THROUGH SATURDAY...VERY ACTIVE PATTERN WITH WARM AND HUMID
CONDITIONS TO START THE MONTH OF MAY. THE FRONT WILL BE SHIFTING
BACK AND FORTH ACROSS THE CWA DURING THIS TIME FRAME WITH NUMEROUS
OPPORTUNITIES FOR THUNDERSTORM ACTION. TUESDAY THROUGH THURSDAY WILL
HAVE MAX TEMPS AROUND 80 WITH DEWPOINTS IN THE HUMID 60S. WITH
INSTABILITY IN PLACE AND THE FRONT NEARBY SEVERE WEATHER WILL BECOME
LIKELY ANYTIME DURING THIS PERIOD. WITH SEVERAL ROUNDS OF HEAVY
RAINFALL WILL NEED TO MONITOR RIVER LEVELS AS THE WEEK PROGRESSES.
THE 12Z ECM HAS THIS FRONT LOCATED IN OR NEAR THE DVN CWA ALL THE
WAY TO MAY 7 WHEN A PATTERN CHANGE TO MUCH COOLER WEATHER ARRIVES.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
305 PM MDT FRI APR 27 2012
.UPDATE...
ISSUED AT 303 PM MDT FRI APR 27 2012
WINDS FINALLY BEGINNING TO MIX TO THE SURFACE WEST OF CWA...WITH
UPSTREAM OBS SHOWING GUSTS 38-44KT. LATEST RUC MATCHES UP PRETTY
WELL WITH CURRENT GUSTS AND ACTUALLY SHOWS WINDS ALOFT WEAKENING AS
THEY MOVE SOUTHEAST TOWARDS OUR CWA. WITH THIS IN MIND CONFIDENCE
IN WARNING CRITERIA BEING MET HAS DECREASED SIGNIFICANTLY...SO
HIGH WIND WARNING WAS DOWNGRADED TO ADVISORY FOR WESTERN
LOCATIONS. EASTERN LOCATIONS UNDER CURRENT WIND ADVISORY HAVE YET
TO CLEAR OUT...SO IM HESITANT TO CANCEL THE ADVISORY FOR THOSE
LOCATIONS DESPITE WINDS HOLDING IN THE 10-20KT RANGE. WILL
CONTINUE TO LET SUBSEQUENT SHIFTS MONITOR.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 236 PM MDT FRI APR 27 2012
THERE WILL BE A POSSIBILITY FOR SHOWERS EARLY THIS EVENING ACROSS
MAINLY THE EASTERN PORTION OF THE AREA ASSOCIATED WITH A DEPARTING
LOW PRESSURE SYSTEM. WIND GUSTS WILL SUBSIDE QUICKLY THIS
EVENING...AND WINDS BETWEEN 10 AND 15 MPH ARE EXPECTED INTO
SATURDAY MORNING. NEEDED TO CONSIDER IF A FROST ADVISORY WOULD BE
NECESSARY OVERNIGHT...BUT GIVEN THE TREND IN THE MODELS TOWARD
SLIGHTLY WARMER TEMPERATURES AND WINDS ABOVE 10 MPH...HAVE NOT
ISSUED AN ADVISORY.
LARGE UPPER LOW WILL REMAIN IN PLACE OVER THE NORTHERN PLAINS
THROUGH SATURDAY NIGHT. A SERIES OF SHORTWAVE TROUGHS ARE EXPECTED
THE UPPER LEVEL PATTERN ACROSS THE CENTRAL PLAINS WILL TRANSITION TO
A WESTERLY ZONAL PATTER BY SUNDAY NIGHT AS THIS UPPER LOW SHIFTS
NORTH INTO SOUTHERN CANADA. THE RESULT WILL BE A VERY ACTIVE
PATTERN OVER OUR CWA AS WEAK SHORTWAVE TROUGHS CONTINUE TO PASS
WITHIN THE VICINITY OF OUR CWA. THE FIRST WAVE IS STILL EXPECTED TO
ARRIVE BY SATURDAY NIGHT...WITH MODELS CURRENTLY SLOWING DOWN THE
ARRIVAL OF LIFT/MOISTURE OVER WESTERN LOCATIONS SATURDAY AFTERNOON
UNTIL SATURDAY EVENING. I TRENDED POPS SATURDAY AFTERNOON BACK AND
ADJUSTED TIMING TO SHOW THE BEST CHANCE FOR RAIN SHOWERS OVERNIGHT
SATURDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 236 PM MDT FRI APR 27 2012
SUNDAY-MONDAY...GUIDANCE IN GENERAL AGREEMENT ON TIMING/POSITION
OF LIFT/MOISTURE SHIFTING EAST THROUGH THE DAY SUNDAY...WITH WEAK
ENERGY LINGERING INTO SUNDAY NIGHT. I ADJUSTED POPS TO SHOW BETTER
CHANCES SUNDAY MORNING TRANSITIONING TO THE EAST BY THE AFTERNOON.
I KEPT BETTER CHANCES ACROSS SOUTHERN AND EASTERN LOCATIONS SUNDAY
NIGHT THROUGH MONDAY MORNING...WITH DECREASING CONFIDENCE ACROSS
THE NORTHERN PART OF THE CWA WHERE THERE IS INDICATION OF
SUBSIDENCE BUILDING IN FROM THE NORTH/NORTHWEST.
THE MAIN STORM TRACK SHIFTS NORTH BY MONDAY...HOWEVER GUIDANCE
CONTINUES TO SHOW WEAK ENERGY PASSING WITHIN THE VICINITY OF OUR
CWA. THERE IS LOT OF VARIABILITY IN MODEL QPF FIELD WITH THESE
FEATURES...WHICH IS NOT SURPRISING CONSIDERING THE FAST NATURE OF
THESE FEATURES AND THE DIFFICULTY GUIDANCE USUALLY HAS AT
RESOLVING THEM AT THIS RANGE. ONLY MINOR CHANGES WERE MADE TO
POP/WX FORECAST BEYOND MONDAY...WITH TOO MUCH UNCERTAINTY IN
TIMING/POSITION OF INDIVIDUAL SMALL SCALE FEATURES.
HIGH TEMPERATURES SATURDAY AND SUNDAY SHOULD REMAIN BELOW NORMAL FOR
MOST OF THE AREA WITH CLOUD COVER AND A COOLER AIRMASS LINGERING
ACROSS THE EASTERN HALF OF THE CWA. FOR NOW TEMPS IN THE LOW TO
UPPER 60S ARE ANTICIPATED SATURDAY. SUNDAY SHOULD BE COOLER WITH
PRECIP AND CLOUDY CONDITIONS LIKELY HOLDING TEMPS BELOW 60F FOR MUCH
OF THE CWA...POSSIBLY COOLER. A WARMING TREND BEGINS MONDAY AS
WESTERLY FLOW BEGINS MODERATING THE AIRMASS OVER THE CENTRAL PLAINS.
WHILE THERE IS UNCERTAINTY IN REGARDS TO SHORTWAVE PASSAGES
AFFECTING HIGH/LOW TEMPS...OVERALL PATTERN FAVORS ABOVE NORMAL
TEMPERATURES THROUGH THE EXTEND PERIODS...WITH HIGHS IN THE UPPER
70S/LOW 80S WEDNESDAY THROUGH FRIDAY. THIS MAY STILL BE TOO COOL IF
SKIES REMAIN CLEAR...AND H85 TEMPS ADVERTISED BY ECMWF VERIFY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1133 AM MDT FRI APR 27 2012
SUB-VFR CONDITIONS ARE EXPECTED EARLY THIS AFTERNOON NEAR AREAS OF
SHOWERS AND THUNDERSTORMS...FOLLOWED BY VFR CONDITIONS OVERNIGHT
AND INTO SATURDAY. STRONG NORTHWESTERLY WINDS WILL DEVELOP BEHIND
THE LOW...WITH KGLD SEEING STRONGER GUSTS THAN KMCK. WINDS WILL
DIMINISH EARLY THIS EVENING...AND SKIES WILL BE MOSTLY CLEAR
OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 6 PM MDT /7 PM CDT/ THIS EVENING FOR
KSZ001>003-013>015-027>029-041-042.
CO...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ090>092.
NE...WIND ADVISORY UNTIL 6 PM MDT /7 PM CDT/ THIS EVENING FOR
NEZ079>081.
&&
$$
UPDATE...DR
SHORT TERM...CJS/DR
LONG TERM...DR
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
354 PM CDT FRI APR 27 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.DISCUSSION...
20Z SURFACE ANALYSIS SHOWS A DRYLINE MIXING EAST THROUGH CENTRAL KS
WITH A COUPLE MORE UPDRAFTS FORMING OUT ACROSS THE WARM SECTOR. THE
WARM FRONT IS A LITTLE DIFFICULT TO PIN DOWN SINCE THERE IS NOT A
DISTINCT CHANGE IN AIRMASS AT THE FRONTAL BOUNDARY. THE DEWPOINT
GRADIENT WOULD SUGGEST THE WARM FRONT MAY HAVE LIFTED AS FAR NORTH
AS CNK TO MHK TO BURLINGTON. PERHAPS THE BEST INDICATOR OF THE WARM
FRONTS LOCATION IS THE AREA OF ELEVATED RADAR RETURNS FROM NEAR
COUNCIL GROVE TO BURLINGTON. GIVEN THE RUC FORECAST OF 0 TO 6 KM
BULK SHEER ON THE ORDER OF 60 KTS AND 0 TO 1 KM SHEER AROUND 35 KTS
WITH IN THE WARM SECTOR...SUPERCELL THUNDERSTORMS ARE POSSIBLE AS
WELL AS THE POTENTIAL FOR A COUPLE TORNADOES. THE LIMITING FACTOR IS
THE WARM SECTOR IS VERY NARROW. STORM MOTION FOR A RIGHT MOVING
STORM IS NORTHEAST AROUND 40 KTS...ALMOST PERPENDICULAR TO THE WARM
FRONT. SO STORMS ARE LIKELY GOING TO MOVE NORTH INTO THE COOLER
BOUNDARY LAYER AIR FAIRLY QUICKLY. ANOTHER LIMITING FACTOR IS THE
AMOUNT OF INSTABILITY...WITH MIXED LAYER CAPES MAYBE REACHING 2000
J/KG. THERE WILL BE A NARROW CORRIDOR WHERE TORNADOES ARE MORE
LIKELY FROM NEAR ABILENE DOWN THROUGH EMPORIA AND PERHAPS JUST NORTH
OF THIS AREA. BECAUSE THE WARM FRONT IS NOT WELL DEFINED...IT WILL
BE DIFFICULT TO JUDGE HOW FAR NORTH A STORM HAS TO GO TO BECOME MORE
ELEVATED.
WOLTERS
LATEST WATER VAPOR IMAGERY SHOWING STRONG UPPER LOW OVER
NORTHWEST KS WHICH SHOULD CONTINUE TO LIFT NORTHEASTWARD INTO
EASTERN NEBRASKA THIS EVENING. AS IT DOES...IT SHOULD ALSO LIFT
CONVECTION RAPIDLY TO THE NORTH AND EAST OF THE CWA BEFORE
MIDNIGHT...OR FURTHER AWAY FROM THE STRONGER INSTABILITY AXIS AS
DRIER AIR WRAPS IN BEHIND THE DRY LINE. THEREFORE DO NOT
ANTICIPATE SEVERE WEATHER THREAT ACROSS THE CWA BEYOND 9 OR 10 PM.
WILL THEN GO DRY ACROSS THE ENTIRE COUNTY WARNING AREA AFTER
MIDNIGHT.
BEYOND MIDNIGHT...FORECAST LOOKS DRY THROUGH THE DAYTIME ON SATURDAY
AS DEEPER MOISTURE AND INSTABILITY IS TEMPORARILY PUSHED SOUTH OF
THE CWA. WILL FAVOR THE COOLER HIGHS IN THE 60S TO THE NORTH OF I
70. HOWEVER...WARM AIR AND MOISTURE ADVECTION WILL DEVELOP ACROSS
THE CWA AHEAD OF THE NEXT SHORTWAVE TROUGH...SO HAVE LOW END POPS
SATURDAY NIGHT ACROSS THE SOUTHEAST FOR THUNDERSTORMS THEN INCREASE
POPS AND CLOUDS ON INTO SUNDAY AS WELL AS LOWERED HIGHS INTO THE LOW
TO MIDDLE 60S. SHORTWAVE TROUGH WILL MOVE INTO THE AREA SUNDAY
NIGHT/EARLY MONDAY WITH THE HIGHEST POPS STILL ALONG AND SOUTHEAST
OF THE TURNPIKE. SHOULD ALSO SEE HIGHER TEMPS AS THE LLVL FLOW
RETURNS TO SOUTHERLY. THEREFORE AFTER HIGHS NEAR 70 ON
MONDAY...SHOULD WARM INTO THE MIDDLE TO UPPER 70S.
WITH THE STRONGER WARM AIR ADVECTION HAVE CONTINUED CHANCE POPS INTO
TUESDAY AND EVEN WEDNESDAY AND THURSDAY AS A SERIES OF SHORTWAVE
TROUGHS ADVANCE NORTHEAST ACROSS THE CENTRAL PLAINS. HIGHS SHOULD
REMAIN WARM NEAR 80 ON INTO FRIDAY.
&&
.AVIATION...
LATEST GUIDANCE REMAINS CONSISTENT IN SHOWING THE MOST LIKELY TIMING
FOR CONVECTION BETWEEN 21Z AND 02Z. SO WILL CONTINUE A TEMPO GROUP
FOR THIS PERIOD. MVFR CIGS ARE ANTICIPATED TO REMAIN JUST WEST OF
TOP AND FOE UNTIL CONVECTION MOVES IN. BIGGEST UNCERTAINTY IS
WHETHER MVFR CIGS WILL MOVE BACK IN AS THE SFC LOW PASSES EAST
OVERNIGHT. THE GFS WANTS TO KEEP THEM NORTH OF THE TERMINALS. GIVEN
THE UNCERTAINTY WILL KEEP A VFR FORECAST FOR NOW WITH SCT025 ON THE
BACK SIDE OF THE LOW...BUT WILL NEED TO KEEP AN EYE ON THIS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1234 AM CDT FRI APR 27 2012
...UPDATED AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 142 PM CDT THU APR 26 2012
EARLY THIS AFTERNOON...THE WATER VAPOR SATELLITE LOOP SHOWED THE
CENTER OF A COMPACT AND INTENSE UPPER LOW OVER WESTERN ARIZONA. A
FEW LIGHTNING STRIKES WERE NOTED JUST AHEAD OF THE INTENSE MID LEVEL
POTENTIAL VORTICITY CENTER TIED TO THE LOW. SIGNIFICANT MID LEVEL
DRYING ON WV LOOP WAS BEGINNING TO ADVANCE EASTWARD TOWARD
WESTERN/CENTRAL NEW MEXICO. 12Z RAOB ANALYSIS REVEALED 140 TO 170
METER HEIGHT FALLS AT 500MB ACROSS FAR SOUTHERN CALIFORNIA WHEN THE
LOW WAS CENTERED NEAR SAN DIEGO EARLIER THIS MORNING. IN THE LOW
LEVELS...A SURFACE LOW WAS POSITIONED ALONG THE RED RIVER NEAR
WICHITA FALLS, TX. THERE WAS A POOL OF SIGNIFICANT MOISTURE AT THE
SURFACE IN THE EASTERLY FLOW NORTH OF THE SURFACE LOW OVER MUCH OF
CENTRAL/SOUTHERN OKLAHOMA WITH 70 DEGREE DEWPOINTS COMMON AS OF
MIDDAY. THE EASTERLY SURFACE WINDS WERE PULLING MID 60S DEWPOINTS AS
FAR NORTHWEST AS LEFORS, TX IN THE EASTERN TEXAS PANHANDLE. THE
EAST-SOUTHEAST WINDS CONTINUED TO ADVECT THIS MOISTURE NORTHWESTWARD
DEEPER INTO THE PANHANDLES.
&&
.SHORT TERM...(THIS EVENING THROUGH DAYBREAK FRIDAY)
ISSUED AT 250 PM CDT THU APR 26 2012
SEVERE WEATHER TONIGHT IS THE MAIN CHALLENGE IN TERMS OF A) TIMING,
B) CONVECTIVE MODE, C) MAIN HAZARDS. THE EVENT IS COMING INTO A BIT
BETTER FOCUS NOW THAT THE EXPECTED BEGINNING OF THE SEVERE WX EVENT
FOR SOUTHWEST KS IS 6-9 HOURS AWAY (AS OF 1930 UTC). SURFACE
DEWPOINTS WILL BE INCREASING NORTHWESTWARD THROUGH THE EVENING WITH
MOIST AXIS EXPECTED TO BE FROM WESTERN OKLAHOMA PANHANDLE INTO
EASTERN TEXAS PANHANDLE WITH 60F ISODROSOTHERM NOSING UP INTO THE
GUYMON, OK AREA BY 03Z. THIS YIELDS ABOUT 1800-2400 J/KG SBCAPE.
THE STRONGEST SURFACE FORCING AT THIS TIME WILL BE JUST WEST OF THE
INSTABILITY AXIS AND CONVECTION SHOULD BE ONGOING FROM SOUTHEAST
COLORADO DOWN INTO THE NORTHWESTERN TEXAS PANHANDLE. AT LEAST THIS
IS HOW THE LATEST RUC13 MODEL IS PLAYING THIS OUT IN THE CONVECTIVE
QPF FIELDS, WHICH MAKES PHYSICAL SENSE GIVEN WHERE THE FORCING IS AT
THAT TIME. THE THING THAT REALLY HAS US CONCERNED IS THE DEGREE OF
SHEAR IN THE 0-1KM AGL LAYER. IN ADVANCE OF THE SMALL SCALE UPPER
LOW...THE AGEOSTROPHIC RESPONSE IN THE LOW LEVELS WILL REALLY BE
MAXIMIZED FROM 03-09Z TONIGHT...AND THE 0-1KM AGL HELICITY WILL
EXCEED 300 M2/S2 OVER A LARGE AREA OF SOUTHWEST KANSAS. THE 0-1KM
ENERGY-HELICITY INDEX WILL REACH THE 4 TO 5 LEVEL, WHICH IS
EXTREMELY HIGH AND MORE THAN ENOUGH TO SUPPORT SIGNIFICANT LOW LEVEL
ROTATION IN THE STRONGEST STORMS...INCLUDING TORNADOES. CONVECTIVE
MODE IS THE REAL CHALLENGE. HOW LONG WILL THE SUPERCELL PHASE
LAST? THE EARLY STORMS COMING OUT OF SOUTHEAST COLORADO WILL MOST
LIKELY BE MORE SCATTERED WITH SOME DISTANCE STILL FROM THE STRONGEST
500-700MB COOLING AND MID LEVEL POTENTIAL VORTICITY (PV) ADVECTION.
WHEN THE "WALL OF FORCING" COMES OUT WITH THE INTENSE MID LEVEL COLD
ADVECTION AND PV ADVECTION...THE MODE WILL MOST LIKELY TRANSITION TO
A QUASI-LINEAR CONVECTIVE SYSTEM (QLCS). WILL HAVE TO REALLY WATCH
OUT FOR QLCS TORNADO EVENTS WHICH COULD BE SHORT-LIVED AND DIFFICULT
TO WARN FOR WITH MUCH LEAD TIME GIVEN THE CHARACTERISTICS OF THIS
TIME OF CONVECTIVE MODE AND THE ASSOCIATED LACK OF INTENSE MID LEVEL
MESOCYCLONES. ANOTHER QUESTION IS HOW FAR SOUTH THIS THREAT WILL
EXTEND INTO SOUTHWEST KANSAS. SEVERAL OF THE MODELS, MAINLY THE
LARGER-SCALE MODELS, INDICATE FAIRLY ROBUST CONVECTIVE QPF AS FAR
SOUTH AS THE OKLAHOMA BORDER BETWEEN 06-12Z. WILL PROBABLY EXTEND
LIKELY POPS DOWN CLOSE TO THE OKLAHOMA BORDER GIVEN THIS. THE
SEVERE WEATHER THREAT WILL CONTINUE ALL NIGHT AND THROUGH 12Z WITH
THE 09-12Z THREAT AREA SHIFTING NORTHEAST TOWARD THE
WAKEENEY-HAYS-LACROSSE AREAS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 353 PM CDT THU APR 26 2012
STORM CHANCES WILL PERSIST IN CENTRAL KANSAS AROUND HAYS THROUGH 20Z
SINCE THE UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE LOW WILL STILL
BE IN THIS AREA THROUGH EARLY AFTERNOON. AS DISCUSSED IN THE SHORT TERM
SECTION, THESE STORMS COULD BE SEVERE. IF STORMS PERSIST LONG ENOUGH
FOR DAYTIME HEATING TO LEAD TO HIGHER CAPE, THEN VERY LARGE HAIL
WOULD BE POSSIBLE AND POSSIBLY A TORNADO. SURFACE WINDS WILL BE
STRONG BEHIND THIS SYSTEM TOMORROW. A WIND ADVISORY WAS ISSUED FOR
MUCH OF SOUTHWEST KANSAS.
AFTER THIS SYSTEM PASSES, THE ASSOCIATED COLD FRONT WILL PASS
THROUGH KANSAS AND THEN STALL OUT ACROSS CENTRAL OKLAHOMA. THE
UPSTREAM SYSTEM THAT CAUSED THE AFOREMENTIONED SYSTEM TO EJECT ACROSS
THE PLAINS WILL HANG BACK OVER THE ROCKIES THROUGH SUNDAY AND
MONDAY. THE ASSOCIATED JET STREAK WILL BE SITUATED ACROSS THE
ROCKIES AND INTO KANSAS THROUGH THIS PERIOD. A WARM ADVECTION
PATTERN WILL DEVELOP AHEAD OF THIS TROUGH. THE GFS/GEM/UKMET
INDICATE QUITE A BIT OF PRECIPITATION ON THE COOL SIDE OF THE FRONT
IN SOUTHWEST KANSAS. HOWEVER, THE ECMWF SCENARIO OF DEVELOPING
WIDESPREAD THUNDERSTORMS ALONG THE FRONT OVER OKLAHOMA AND SOUTH
CENTRAL KANSAS COULD PREVENT SIGNIFICANT RAINFALL FURTHER NORTH.
HOWEVER, 20-40% THUNDERSTORM CHANCES WERE MAINTAINED FROM SATURDAY
NIGHT THROUGH MONDAY GIVEN THE UNCERTAINTY. CLOUDS AND POSSIBLE
PRECIPITATION CHANCES TO THE NORTH OF THE FRONT WILL PROBABLY KEEP
HIGH TEMPERATURES IN THE 60S TO LOWER 70S WITH LOWS IN THE 40S AND
50S.
BY TUESDAY AND WEDNESDAY, THE NEXT JET STREAK WILL BE MOVING ACROSS
THE ROCKIES AND APPROACHING THE CENTRAL HIGH PLAINS. FRONTOLYSIS
WILL OCCUR OVER OKLAHOMA, WITH ANOTHER FRONT DEVELOPING ACROSS THE
NORTHERN OR CENTRAL PLAINS. A DRYLINE AND SURFACE FRONT WILL
INTERSECT SOMEWHERE ACROSS THE CENTRAL HIGH PLAINS REGION.
THUNDERSTORMS CANNOT BE RULED OUT EITHER DAY AS 60F DEWPOINTS
WILL BE IN PLACE AHEAD OF THE DRYLINE. IT WILL BE WARMER BY THIS
TIME, WITH HIGHS IN THE UPPER 70S AND 80S AND LOWS IN THE 50S TO
LOWER 60S. THE HIGHEST MINIMUM TEMPERATURES, AS IS TYPICAL, WILL BE
IN SOUTH CENTRAL KANSAS WHERE DEWPOINTS WILL BE HIGHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1234 AM CDT FRI APR 27 2012
AN AREA OF SURFACE LOW PRESSURE WILL MOVE OUT OF EASTERN COLORADO
AND INTO NORTHWESTERN COLORADO OVERNIGHT. THIS WILL INCREASE
THUNDERSTORM CHANCES OVERNIGHT. VFR CONDITIONS WILL CHANGE TO MVFR
TO IFR CONDITIONS AS THESE THUNDERSTORMS PASS OVER THE TERMINALS.
WINDS WILL GENERALLY BE FROM THE SOUTHEAST OVERNIGHT SHIFTING TO
THE SOUTH BY SUNRISE. WIND SPEED WILL QUICKLY INCREASE TO AROUND
20 KNOTS AS THIS LOW APPROACHES. GUSTS OVER 30 KNOTS CAN NOT BE
RULED OUT. A COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED LOW
WILL MOVE THROUGH THE AREA TOMORROW MORNING SHIFTING THE WINDS TO
THE NORTHWEST AND INCREASE WINDS TO AROUND 25 KNOTS WITH GUSTS
AROUND 35 KNOTS. CLEAR SKIES AND VFR CONDITIONS ARE ANTICIPATED
BEHIND THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 69 46 63 / 0 0 40 30
GCK 43 68 45 62 / 0 0 30 30
EHA 43 68 44 65 / 0 0 30 30
LBL 45 69 46 65 / 0 0 40 30
HYS 43 67 44 61 / 0 0 30 30
P28 51 71 48 63 / 0 0 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 8 PM CDT
/7 PM MDT/ THIS EVENING FOR KSZ043>045-061>065-075>080-086>088.
&&
$$
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...HOVORKA 42
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1149 PM CDT THU APR 26 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT TERM (TODAY THROUGH FRIDAY)...
19Z WATER VAPOR SHOWS A SHORTWAVE LIFTING EAST THROUGH AZ WITH A
LONG WAVE TROUGH OVER THE PACIFIC NORTHWEST. MID LEVEL RIDGING
REMAINS OVER THE CENTRAL PLAINS. AT THE SFC 19Z OBS SHOWED RIDGING
THROUGH MUCH OF KS WITH A FRONTAL BOUNDARY NEAR THE RED RIVER
VALLEY. A BAND OF LIGHT SHOWER ACTIVITY HAS SET UP WITHIN A NARROW
AXIS OF ISENTROPIC UPGLIDE ACROSS CENTRAL KS.
FOR THIS AFTERNOON AND THIS EVENING...THE RUC AND NAM SHOW THE
NARROW AXIS OF ISENTROPIC LIFT ON THE 310K SFC GRADUALLY LIFTING
NORTH AND EAST. BECAUSE OF THIS HAVE INCLUDED SOME SCATTERED SHOWERS
ACROSS NORTH CENTRAL KS WERE MID LEVEL MOISTURE IS A LITTLE BETTER.
THE NEXT SHIFT WILL NEED TO WATCH THE EASTWARD PROGRESSION. BUT
FOR NOT THINK SHOWERS WILL HAVE A HARD TIME MOVING EAST DUE TO A
LITTLE MORE DRY AIR IN THE MID LEVELS.
OVERNIGHT...THE SHORTWAVE OVER AZ WILL LIFT OUT OF THE SOUTHERN
ROCKIES AND MOVE INTO SOUTHERN NEB THROUGH THE DAY FRIDAY. THIS WAVE
IS EXPECTED TO PROVIDE THE FORCING TO SPARK CONVECTION LATE TONIGHT
AND THROUGH THE DAY FRIDAY. AT THIS POINT IT LOOKS LIKE THERE COULD
BE ELEVATED CONVECTION FORM DURING THE MORNING HOURS AND LIFT ACROSS
NORTHEAST KS. BOTH THE NAM AND GFS SHOW A NARROW WARM SECTOR
DESTABILIZING BY THE LATE MORNING OR EARLY AFTERNOON WITH SURFACE
BASED CAPES ON THE ORDER OF 1000 TO 1500 J/KG. WHILE A LITTLE ON THE
MARGINAL SIDE...DEEP LAYER SHEER OF 50 KTS WOULD BE SUFFICIENT FOR
STORMS IN THE WARM SECTOR TO BECOME SUPERCELLS. AT THIS POINT THE
MODELS PROG THE WARM FRONT TO SET UP JUST TO THE SOUTHWEST OF THE
FORECAST AREA WITH IT LIFTING NORTHEAST TOWARDS A CNK TO EMP LINE BY
FRIDAY EVENING. STORMS SOUTHWEST OF THIS LINE WILL HAVE THE GREATER
LIKELY HOOD OF BECOMING SEVERE. ALTHOUGH ELEVATED STORMS ACROSS
NORTHEAST KS COULD ALSO HAVE HAIL WITH THEM. THERE COULD BE AN
ISOLATED TORNADO THREAT ALONG THE WARM FRONT AS WELL IF A STORM WERE
TO DEVIATE TO THE SOUTHEAST AND RIDE ALONG THE BOUNDARY TAPPING INTO
THE GREATER HELICITY JUST NORTH OF THE BOUNDARY. WITH A CONVERGENCE
IN SOLUTIONS AMONG THE MODELS...HAVE INCREASED POPS INTO THE
CATEGORICAL RANGE ACROSS NORTHERN KS WHERE THE BEST FORCING IS
ANTICIPATED. HAVE LIKELY POPS ACROSS EAST CENTRAL KS THINKING THAT
COVERAGE OF STORMS MAY BE A LITTLE MORE BROKEN IN NATURE.
FRIDAY IS ALSO EXPECTED TO BECOME WINDY AS THE SFC LOW DEEPENS TO
THE WEST. THE INCREASING PRESSURE GRADIENT WILL LIKELY CAUSE EAST
AND SOUTHEAST WINDS TO GUST OVER 30 MPH. LOWS TONIGHT SHOULD NOT
DROP OFF AS MUCH GIVEN INCREASING CLOUD COVER AND A BETTER MIXED
BOUNDARY LAYER. THINK LOWS WILL BE IN THE MID 50S TO AROUND 60 FOR
MOST LOCATIONS. EXPECT A GOOD GRADIENT IN MAX TEMPS FOR TOMORROW
WITH CLOUDS AND EASTERLY WINDS KEEPING HIGHS IN THE LOW 60S OVER FAR
NORTHEAST KS. NEAR AND SOUTHWEST OF THE WARM FRONT...HIGHS SHOULD
WARM INTO THE MID 70S.
WOLTERS
MID TERM (FRIDAY EVENING THROUGH SUNDAY)...
BY FRIDAY EVENING MODELS AGREE ON A SIMILAR POSITION OF THE UPPER
TROUGH AND SURFACE LOW ACROSS CENTRAL INTO NORTHEAST KANSAS. SHOWERS
AND THUNDERSTORMS WILL REMAIN POSSIBLE EARLY FRIDAY EVENING BEFORE
THE SYSTEM QUICKLY EXITS NORTHEAST AND A DRIER AIR MASS FILLS IN ITS
PLACE WITH THE PASSAGE OF A COLD FRONT. BY SATURDAY MORNING THE
FRONTAL BOUNDARY WILL STALL NORTHEAST TO SOUTHWEST OVER SOUTHERN
KANSAS INTO CENTRAL OKLAHOMA. SURFACE RIDGE SETTLING OVER THE CWA
SHOULD KEEP MUCH OF THE AREA STABLE AND CAPPED THROUGHOUT THE
SATURDAY AFTERNOON PERIOD BEFORE ADDITIONAL SHOWERS AND A POSSIBLE
THUNDERSTORM OR TWO DEVELOPS ALONG AND NORTH OF THE BOUNDARY. WHILE
MUCH OF THE INSTABILITY REMAINS JUST SOUTH OF THE CWA...WOULD NOT BE
SURPRISED FOR AN ISOLATED THUNDERSTORM OR TWO. BEST CHANCE FOR
PRECIP ATTM APPEARS TO BE SUNDAY AFTERNOON INTO THE EVENING HOURS AS
ISENTROPIC LIFT INCREASES AND THE WARM FRONT LIFTS NORTHWARD. THE
COVERAGE AND SEVERITY OF ANY THUNDERSTORM STILL REMAINS UNCERTAIN AS
THE MODELS DEPICT VARYING SOLUTIONS ON THE PLACEMENT OF THE WARM
FRONT WITH RESPECT TO OUR AREA. HOWEVER...AMPLE MOISTURE ASSOCIATED
WITH THE BOUNDARY AND THE PRESENCE OF A SHORTWAVE TROUGH PASSING
THROUGH SUNDAY EVENING LEADS TO A DECENT CHANCE FOR ADDITIONAL
PRECIPITATION. TEMPERATURES STILL APPEAR TO BE ON TRACK FOR SATURDAY
AS CLEARER SKIES AND WEAK COLD AIR ADVECTION BEHIND THE SYSTEM SHOULD
HELP RAISE HIGHS INTO THE MIDDLE AND UPPER 60S TOWARDS EAST
CENTRAL KANSAS. CLOUD COVER ON SUNDAY WILL INHIBIT TEMPS TO ONLY
THE LOWER 60S.
EXTENDED TERM (SUNDAY EVENING THROUGH THURSDAY)...
VERY UNSETTLED PATTERN FOR THE EXTENDED TERM WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS EACH DAY. A STALLED SURFACE FRONT SUNDAY
EVENING INTO EARLY NEXT WEEK WILL PROVIDE THE SURFACE CONVERGENCE
ALONG WITH A SERIES OF SHORTWAVES EJECTING FROM THE MAIN TROUGH
OVER THE PACIFIC NORTHWEST INTO THE CENTRAL AND NORTHERN PLAINS.
MODELS ARE STILL HAVING DIFFICULTY WITH RESPECT TO THE TIMING OF
EACH SHORTWAVE TROUGH TO AFFECT THE CWA COMBINED LACK OF STRONG
FORCING FROM ANY FRONTAL BOUNDARIES. REGARDLESS...CONTINUOUS WARM
AIR ADVECTION AND DEWPOINTS RANGING FROM THE UPPER 50S TO MIDDLE
60S SUGGEST CONTINUING CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THURSDAY. SOUNDING PROFILES SHOW 0-6KM BULK SHEAR VALUES
MARGINAL AROUND 35 KTS WITH MIXED LAYER MUCAPE BETWEEN 1100 AND
1500 J/KG SUGGEST ANY STORMS ABLE TO DEVELOP WILL BE ELEVATED AND
COULD BE STRONG. HEAVY RAIN MAY ALSO BE LIKELY AS BOTH THE GFS AND
ECMWF SHOW PWAT VALUES WELL OVER AN INCH FOR EACH PERIOD IN THE
FORECAST. MAIN CONCERN WILL BE IF THE MAIN FORCING ALOFT WILL
COINCIDE WITH ANY SURFACE FEATURES TO ALLOW THE STRONGER STORMS TO
FORM. BESIDES THE PRECIP POSSIBILITIES...NEAR NORMAL TEMPERATURES
ON MONDAY ARE EXPECTED TO GRADUALLY WARM INTO THE UPPER 70S BY
THURSDAY AS THE THERMAL RIDGE AXIS STRETCHES NORTHWARD OVER THE
CENTRAL PLAINS.
BOWEN
&&
.AVIATION...
GIVEN LATEST TRENDS...HAVE SLOWED ONSET OF MVFR CIGS AND PRECIP
AS WELL AS THE IMPROVING TIMING AROUND 20Z. STILL NOT CONFIDENT
ENOUGH TO INCLUDE ANY TS AROUND 0Z. NOT CERTAING ON TIMING OF
WINDS INCREASING AROUND 12Z...WITH POSSIBLE VCSH HINDERING BETTER
MIXING.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
709 AM CDT FRI APR 27 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
/ISSUED AT 330 AM FRI APR 27 2012/
UPPER AIR PATTERN A BIT COMPLICATED WITH STRONG UPPER TROF MOVING
ACROSS THE PACIFIC NW AND THEN CLOSING OFF LATTER TODAY INTO THE
NORTHERN PLAINS AND REMAINING QUASI-STATIONARY IN THE DKTS OVER
THE WEEKEND. THE OTHER TROUGH...WHICH WILL BE THE MAIN PLAYER IN OUR
WEATHER IS CURRENTLY LIFTING OUT OF THE SW U.S. AND WILL DAMPEN AS
IT ENCOUNTERS BLOCKING RIDGE ACROSS UPPER MIDWEST. MODELS ARE A
BIT LESS AGGRESSIVE ON QPF OUTPUT THAN THEY WERE 24 HOURS
AGO...BUT STILL IN FAIRLY GOOD AGREEMENT THAT A PERSISTENT PERIOD
OF RAIN WILL DEVELOP TONIGHT AND INTO SATURDAY ACROSS MOST OF OUR
AREA.
FIRST WAVE OF -RA IS ADVANCING INTO WC/SW MN...BUT IS BATTLING WITH
DRY ELY FLOW...BUT A FEW METARS ARE SHOWING -RA OUT OF MID CLOUDS.
HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON THIS FIRST SHOT OF -RA
GRADUALLY WEAKENING IT AS IT CONTINUES TO MOVE EAST INTO DRY RIDGE
OF HIGH PRESSURE. SO LEFT AREAS FROM AROUND STAPLES TO HCD TO AEL
DRY FOR TODAY. ALSO BUMPED UP HIGH TEMPERATURES JUST A BIT FOR THOSE
AREAS WHICH SHUD REMAIN DRY. AFTERNOON RH SHUD DROP INTO THE MID 20
PERCENT RANGE ACROSS MOST OF WI CWA AND UPPER 20S PERCENT FOR
ADJOINING AREAS OF MN. CLOUD COVER AND A BIT OF -RA WILL KEEP AFTN
RH ABOVE 30 PERCENT REMAINDER OF AREA. SURFACE PRESSURE GRADIENT
TIGHTENS DURING THE DAY IN RESPONSE TO PRESSURE FALLS AHEAD OF LOW
PRESSURE TROF ACROSS THE DKTS INTO W KS. WILL SEE GUSTS THIS AFTN 30
MPH OR BETTER ACROSS MUCH OF WC INTO SC MN.
TONIGHT THE PIECES COME TOGETHER BETTER FOR PRECIPITATION AS THE SW
U.S. WAVE LIFTS TOWARD AREA PROVIDING A RATHER LENGTHY PERIOD OF
ISENTROPIC LIFT. DRY ELY FLOW WILL PROVIDE A GOOD SETUP FOR WETBULB
COOLING AS LIFT FROM THE APPROACHING TROF FURTHER COOLS THE COLUMN.
DON`T EXPECT ANY SNOW ACCUMS...BUT PROGGED SOUNDINGS DO BECOME COLD
ENUF FOR A MIX ACROSS MOST OF THE AREA. QPF AMOUNTS FROM TONIGHT
INTO SATURDAY NIGHT WILL SHOW A WIDE RANGE FROM PERHAPS AN INCH OUT
IN WC MN TO A TRACE TO A FEW HUNDREDTHS IN NW PTN OF WI CWA.
RIDGE REASSERTS ITSELF ON SUNDAY AS THE SW U.S. TROF SHEARS OUT TO
THE EAST AND BECOMES ABSORBED BY THE RIDGE AND DKTS UPPER LOW BEGINS
TO LIFT INTO SASK.
MODERATING TEMPS NEXT WEEK AS UPPER FLOW BECOMES ZONAL TO SW...BUT
PATTERN DOES LOOK ACTIVE...ESPECIALLY ON TUESDAY INTO WEDNESDAY AS A
STRONG TROF MOVES ACROSS THE REGION.
&&
.AVIATION.../12Z TAF ISSUANCE/
BAND OF ELEVATED SHOWERS HAS MOVED INTO SW MN THIS MORNING...BUT
VERY DRY LOW LEVELS HAS MADE IT DIFFICULT FOR MUCH OF THIS
ACTIVITY TO MAKE IT TO THE GROUND. HRRR HANDELING THIS MORNING
ACTIVITY WELL AND IT CONTINUES TO ADVERTISE THIS AREA OF SHOWERS
DIMINISHING THROUGH THE MORNING AS THE FORCING WANES AND IT
CONTINUES TO ENCOUNTER THE DRY AIR. AFTER THAT DO NOT ANTICIPATE
ANY PRECIP AT TERMINALS UNTIL WAVE CURRENTLY EXITING COLORADO MOVES
UP THIS DIRECTION. SLOWED QUITE A BIT THE ONSET OF PRECIP AT TAFS
AS DRY AIR LOOKS TO BE RATHER DIFFICULT TO OVERCOME. LOOKING AT
LATEST NAM REFLECTIVITY FORECAST...CURRENT TAFS MAY NOT BE SLOW
ENOUGH. EXPECT CIGS TO REMAIN VFR UNTIL THE END OF THE TAF AT RWF
AND MAYBE MSP. PRESSURE GRADIENT WILL BE STRENGTHENING THROUGH THE
DAY...SO DO LIKE GOING STRONG ESE WINDS IN TAFS. IS INTERESTING TO
NOTE THAT STRONGEST WINDS OFF THE 06Z NAM COME BETWEEN 00Z AND 06Z
SAT...WHEN ITS SHOWING AXN/RWF COULD SEE 25G35KT TYPE WINDS. KEPT
P-TYPE ALL LIQUID AT THIS POINT...WITH CHANCES FOR SNOW LOOKING
MARGINAL AT BEST RIGHT NOW WITH THINGS STAYING JUST WARM ENOUGH TO
KEEP PRECIP AS RAIN.
KMSP...WITH BEST FORCING AND DEEPER MOISTURE NOT PEGGED TO COME
OVER THE FIELD UNTIL AFTER 06Z...DELAYED PRECIP ONSET QUITE A
BIT. COULD CERTAINLY SEE PRECIP EARLIER THAN 06Z IF RATES ARE
STRONG ENOUGH TO FORCE THE RAIN THROUGH ABOUT 8K FT OF DRY AIR. AT
THE SAME TIME...THERE IS A CHANCE NO RAIN IS SEEN THIS TAF PERIOD
AT ALL. FOR CIGS...ASSUMING RAIN STARTS BY 09Z...THEN IT IS LIKELY
THAT AT SOME POINT DURING SAT MORNING CIGS WILL BECOME MVFR. FOR
WINDS...THEY LOOK STRONG THE WHOLE 30 HOURS...BUT FAIRLY PERSISTENT
IN THE 090-120 DIRECTION.
//OUTLOOK...SATURDAY THROUGH TUESDAY...
.SAT-SAT NGT...-SHRA DIMINISHING OVERNIGHT. IFR/MVFR CIGS LIKELY
WITH PERIOD OF MVFR VIS.
.SUN...IFR/MVFR CIGS LIKELY WITH PERIODS OF LIGHT RAIN EARLY.
.MON...IFR/MVFR CIGS EARLY...BECOMING VFR IN THE AFTERNOON.
.TUE...CHC -TSRA AFTERNOON INTO THE NIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ANOKA-BENTON-
DOUGLAS-ISANTI-SHERBURNE-STEARNS-TODD-WASHINGTON.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR CHISAGO-KANABEC-
MILLE LACS-MORRISON.
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR DUNN-PEPIN-PIERCE-
ST. CROIX.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR BARRON-CHIPPEWA-
EAU CLAIRE-POLK-RUSK.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
734 PM CDT SAT APR 28 2012
...UPDATE TO AVIATION...
...MESOSCALE CONVECTIVE DISCUSSION...
.UPDATE...
/ISSUED 733 PM CDT SAT APR 28 2012/
THE NATIONAL WEATHER SERVICE WILL BE MONITORING A DEVELOPING
THUNDERSTORM COMPLEX TAKING SHAPE OVER WEST TEXAS. WE`RE
BECOMING MORE CONFIDENT THAT THIS FEATURE WILL APPROACH EXTREME
SOUTHEAST KANSAS AND THE MISSOURI OZARKS SOMETIME AFTER 3 AM.
A SURFACE FRONT REMAINS JUST NORTH OF JOPLIN TO JUST SOUTH OF
VICHY. WHILE THE ATMOSPHERE ALONG AND SOUTH OF THE BOUNDARY IS
UNSTABLE AND UNCAPPED...NO DEEP CONVECTION HAS BEEN OBSERVED
ACROSS SOUTHWEST MISSOURI THIS EVENING. THIS IS MAINLY DUE TO THE
LACK OF A FORCING MECHANISM STRONG ENOUGH TO TRIGGER
STORMS...HOWEVER...THIS WILL CHANGE WITH TIME.
FOR THE REST OF THIS EVENING...WILL CONTINUE WITH A PERSISTENCE
FORECAST. OCCASIONAL NARROW UPDRAFTS WILL DEVELOP AND WEAKEN NEAR
AND TO THE NORTH OF THE SURFACE FRONT. WILL ALTER THE ONGOING POP
FORECAST THIS EVENING TO BETTER ALIGN WITH THE BOUNDARY.
OTHERWISE...ATTENTION WILL BE FOCUSED ACROSS TEXAS AND SOUTHWEST
OKLAHOMA...WHERE A SHORTWAVE WILL LIFT NORTHEAST AND PROVIDE A
FOCUS FOR SHOWERS AND THUNDERSTORMS.
THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET...IN CONJUNCTION
WITH AN INCREASING LOW LEVEL JET...WILL AID IN GROWTH OF A
THUNDERSTORM COMPLEX. THIS ACTIVITY WILL TAKE SOME TIME TO MOVE
INTO SOUTHWEST MISSOURI AND SOUTHEAST KANSAS...AND MAY NOT ARRIVE
UNTIL 4 AM. WE WILL BE KEEPING A VERY CLOSE EYE ON HOW THINGS
EVOLVE TO THE SOUTHWEST...AND WILL UPDATE TIMING AND ARRIVAL OF
THIS IMPENDING COMPLEX OF STORMS AS WE GATHER ADDITIONAL
INFORMATION.
REGARDING THE SOUTHERN MISSOURI STORM ENVIRONMENT LATE TONIGHT
INTO EARLY SUNDAY MORNING...THE LATEST RUC AND H-TRIP MODELS
SUGGESTS THAT THE ATMOSPHERE WILL REMAIN UNSTABLE. MIXED LAYER
CAPE VALUES WILL PERSIST AT AROUND 1500 J/KG...WITH MIXED LAYER
INHIBITION VALUES RIDING A FINE LINE AT AROUND -50 J/KG.
AT THIS POINT...WE CANNOT COMPLETELY RULE OUT BOUNDARY LAYER BASED
CONVECTION. RAOB AND SURFACE OBSERVATIONS THROUGH THE OVERNIGHT
HOURS...WILL GIVE US AN IDEA IF BOUNDARY LAYER BASED STORMS ARE
PROBABLE TOWARD EARLY SUNDAY MORNING.
THERE AT LEAST REMAINS A LIMITED RISK OF A FEW STORMS CAPABLE OF
MARGINALLY SEVERE HAIL. IF A FEW BOWING SEGMENTS CAN BE REALIZED
IN THE WARM SECTOR...THERE WILL BE RISK FOR A LOCALIZED DAMAGING
WIND GUSTS.
GAGAN/CRAMER
&&
.DISCUSSION...
/ISSUED 3 PM CDT SAT APR 28 2012/
A STALLED FRONT STRETCHED FROM NORTHEASTERN OKLAHOMA INTO EAST
CENTRAL MISSOURI JUST NORTH OF THE INTERSTATE CORRIDOR. EVEN
THOUGH EXTENSIVE CLOUD COVER PERSISTED EARLY THIS AFTERNOON THE
AIR MASS HAD DESTABILIZED WITH MIXED LAYERED CAPE NEAR 2000 J/KG
ACROSS SOUTHERN MISSOURI.
ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE THE REMAINDER OF
THE AFTERNOON INTO THE EVENING. DEVELOPMENT MAY BE FOCUSED ACROSS
THE CENTRAL MISSOURI AND THE EASTERN OZARKS EASTWARD INTO EAST
CENTRAL MISSOURI WITHIN AN AXIS OF BETTER CONVERGENCE. A STRONG TO
MARGINALLY SEVERE STORM CANNOT BE RULED OUT GIVEN MODERATE DEEP
LAYERED SHEAR AND RELATIVELY STEEP MID LEVEL LAPSE RATES.
CONVECTION IS EXPECTED TO INCREASE LATER TONIGHT ALONG AND NORTH
OF THE BOUNDARY AS A LOW LEVEL JET DEVELOPS. THIS ACTIVITY IS
EXPECTED TO BE FOCUSED FROM SOUTHEASTERN KANSAS INTO SOUTHWEST AND
CENTRAL MISSOURI. WILL HAVE TO MONITOR THE POTENTIAL OF STRONG TO
POSSIBLY SEVERE STORMS OVERNIGHT...BUT CONSIDERABLE UNCERTAINTY
EXISTS ON TRIGGERING MECHANISMS GIVEN THE COMPLEX ENVIRONMENT.
CONVECTION WILL LIKELY BE ONGOING SUNDAY MORNING BUT WILL LIKELY
DIMINISH THROUGH THE MORNING HOURS. THE FRONT MAY LIFT NORTH A
BIT ON SUNDAY BUT REMAIN IN CLOSE PROXIMITY TO THE AREA. THE CLOSE
PROXIMITY OF THE BOUNDARY AND THE APPROACH OF A SHORTWAVE WILL
INSTIGATE CONVECTIVE DEVELOPMENT SUNDAY AFTERNOON AND EVENING.
SUFFICIENT DESTABILIZATION ALONG WITH DEEP LAYERED SHEAR AROUND 50
KTS WILL SUPPORT STORM ORGANIZATION THE POTENTIAL FOR SEVERE
STORMS. PROGGED MODEL SOUNDINGS SUGGEST A MORE FAVORABLE
ENVIRONMENT THAN TODAY FOR SEVERE STORMS ALONG AND SOUTH OF THE
FRONT SUNDAY AFTERNOON. A LIMITING FACTOR TO STORM SEVERITY COULD
BE LINGERING MORNING CONVECTION AND CLOUD COVER.
THE FRONT WILL DIMINISH WITH TIME WHILE IT CONTINUES TO MEANDER
ACROSS THE REGION INTO EARLY NEXT WEEK. A COUPLE MORE DISTURBANCES
WILL ALSO TRACK ACROSS THE REGION MONDAY AND TUESDAY. THE FEATURES
WILL MAINTAIN THE CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY AND
TUESDAY. SEVERE POTENTIAL APPEARS TO BE MARGINAL AT THIS TIME.
HOWEVER WE WILL HAVE TO MONITOR THE POTENTIAL DEVELOPMENT OF HEAVY
RAINFALL AS A FEW IF NOT SEVERAL ROUNDS OF CONVECT IO MAY IMPACT
THE SAME AREAS OVER THE NEXT FEW DAYS.
IT APPEARS WE WILL BECOME WELL ESTABLISHED IN THE WARM SECTOR
WEDNESDAY WHILE ANOTHER FRONT TAKES SHAPE ACROSS THE PLAINS. THIS
SYSTEM WILL MAKES IT WAY ACROSS THE REGION THURSDAY FOR ANOTHER
CHANCE OF CONVECTION.
FOSTER
&&
.AVIATION...
FOR THE 00Z TAFS...VERY CHALLENGING FORECAST OVER THE NEXT 24
HOURS. SURFACE BOUNDARY JUST TO THE NORTH OF JLN/SGF WILL CONTINUE
FOCUS ISOLATED/WIDELY SCATTERED SHRA/TSRA THIS EVENING. THIS
ACTIVITY SHOULD SUBSIDE THIS EVENING. AFTER MIDNIGHT...ALL EYES
WILL BE ON SHRA/TSRA DEVELOPMENT OVER TX/OK THAT MAY PROGRESSIVELY
MOVE NORTHEAST WITH TIME OVERNIGHT. DUE TO UNCERTAINTY WITH THE
EVENTUAL EVOLUTION...AND LOCATION OF THIS ACTIVITY HAVE REMAINED
CONSERVATIVE AND MAINTAINED PROB30 GROUPS AT ALL SITES. MOS/LAMP
AND SREF PROBABILITIES ALL CONTINUE TO INDICATE A DEVELOPING
STRATUS DECK AT SOME JUNCTURE OVERNIGHT INTO SUNDAY MORNING. HAVE
MAINTAINED LOW END MVFR...BUT CANNOT RULE OUT IFR.
GAGAN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1216 PM CDT FRI APR 27 2012
...UPDATE TO AVIATION...
.UPDATE...
/ISSUED 1035 AM CDT FRI APR 27 2012/
THE SEVERE WEATHER THREAT CONTINUES FOR THIS AFTERNOON AND
EVENING...ESPECIALLY FOR AREAS ALONG THE U.S. 71 CORRIDOR IN
SOUTHEASTERN KANSAS AND WESTERN MISSOURI.
A STRONG SHORTWAVE CONTINUES TO PUSH EAST OVER WESTERN KANSAS LATE
THIS MORNING...WITH AN ASSOCIATED WELL DEVELOPED AREA OF LOW
PRESSURE AT THE SURFACE. AS OF 15Z...A WARM FRONT STRETCHED FROM
NEAR WICHITA TO MIAMI OK TO LITTLE ROCK.
THE WARM FRONT/WARM SECTOR OF THIS SYSTEM SHOULD BEGIN TO
OVERSPREAD THE WESTERN PORTIONS OF THE CWA THIS AFTERNOON...LIKELY
MIXING NORTHEAST TO ROUGHLY U.S. 65 BY 00Z. I DO HAVE SOME CONCERN
AS TO WHETHER MODEL GUIDANCE IS UNDER-PLAYING THE SPEED OF THE
WARM FRONT...AS A COMBINATION OF STRONG PRESSURE AND HEIGHT
FALLS...ALONG WITH A BIT OF OCCASIONAL SUNSHINE NORTH OF THE WARM
FRONT...COULD RESULT IN VERY RAPID NORTHWARD MOVEMENT LATE THIS
AFTERNOON.
WHILE THE WARM SECTOR IS CURRENTLY QUITE CAPPED PER 12Z
RAOBS...A SERIES OF VORT MAXES WRAPPING AROUND THE MAIN UPPER
LOW/SHORTWAVE WILL ACT TO ERODE MUCH OF THAT INHIBITION BY 21Z. AT
THE SAME TIME...AN APPROACHING...AND PERHAPS SURGING...DRYLINE AND
COLD FRONT WILL APPROACH EASTERN KANSAS...SERVING AS THE FOCUS FOR
THUNDERSTORM DEVELOPMENT BETWEEN 18Z AND 21Z WEST OF THE CWA.
CELLS WILL LIKELY MOVE INTO THE U.S. 71 CORRIDOR BETWEEN 21Z AND
23Z. 12Z NAM AND 12/13Z RUC CONTINUE TO SUPPORT SUPERCELLS...WITH
AN ASSOCIATED RISK OF VERY LARGE HAIL...STRONG WINDS...AND
TORNADOES. THE TORNADO THREAT APPEARS TO BE MAXIMIZED ACROSS
EASTERN KANSAS AND THE WESTERN TIER OR TWO OF COUNTIES IN
MISSOURI...EXTENDING SOUTH INTO NORTHEASTERN OKLAHOMA. WITH STRONG
THERMODYNAMIC AND KINEMATIC PARAMETERS IN PLACE...AN ISOLATED
STRONG TORNADO CAN NOT BE RULED OUT ACROSS THIS AREA.
STORMS WILL CONTINUE TO PUSH EAST THIS EVENING TOWARD THE U.S. 65
CORRIDOR...THOUGH THE EASTERN EXTENT OF THE SEVERE WEATHER THREAT
REMAINS DEPENDENT ON HOW FAR THE WARM SECTOR BUILDS INTO MISSOURI.
THE OVERALL SEVERE THREAT LATE TONIGHT SHOULD BE MITIGATED A BIT
BY A COOLING/INCREASINGLY INHIBITED BOUNDARY LAYER...THOUGH
ISOLATED SEVERE STORMS WILL BE POSSIBLE THROUGH MIDNIGHT.
BOXELL
&&
.DISCUSSION...
MAIN CONCERNS FOR THE FORECAST PACKAGE FOCUS ON THE POTENTIAL FOR
SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING.
EARLY MORNING CONDITIONS ACROSS THE OZARKS AND SOUTHEASTERN
KANSAS HAVE DEWPOINTS IN THE 50S WITH TEMPERATURES IN THE 60S
NORTH OF A FRONT LAID OUT ACROSS CENTRAL ARKANSAS. THIS IS THE
COLD FRONT THAT MOVED THROUGH THE OZARKS YESTERDAY MORNING AND IT
WILL BEGIN TO MOVE ITS WAY NORTH AS A WARM FRONT TODAY AND BRING A
RETURN OF SOUTHERLY WINDS AND ADDITIONAL MOISTURE TO THE REGION.
THIS WILL BRING THE POTENTIAL FOR SEVERE WEATHER TO THE REGION
THIS AFTERNOON AND EVENING.
CURRENT SHORT TERM MODELS HAVE THE WARM FRONT LIFTING THROUGH THE
OZARKS THROUGH THE DAY TODAY AS SURFACE LOW PRESSURE NOW OVER
EASTERN COLORADO AND WESTERN KANSAS TRACKS EAST ACROSS THE PLAINS.
THIS WILL OCCUR IN RESPONSE TO THE UPPER LEVEL SHORT WAVE/CLOSED
LOW MOVING EAST. THE LEFT EXIT REGION OF A 250MB/500MB JET MAX WILL
BEGIN TO ROUND THE BEND OF THE UPPER TROUGH AND PROVIDE GOOD
DIFFLUENCE ALOFT. THIS WILL BE OCCURRING OVER A REGION OF
INCREASING INSTABILITY WITH MLCAPE VALUES VIA THE NAM UP TO AROUND
2000 J/KG...WITH 150 J/KG IN THE 0-3 KM LAYER. WHILE THE MODELS DO
TEND TO OVER DO THE LOW LEVEL CAPE...EVEN TAKING HALF OF THE
MODEL OUTPUT WOULD BE ENOUGH FOR SEVERE STORMS TO DEVELOP. THIS
WILL OCCUR IN CONJUNCTION WITH 0-3 KM BULK SHEAR AROUND 50-60
KTS AND 0-1 KM STORM RELATIVE HELICITY VALUES OVER 400M2/S2.
WOULD EXPECT THAT AREAS WEST OF HIGHWAY 65 IN GENERAL WILL HAVE
THE BEST CHANCES FOR SEVERE STORMS...WITH LARGE HAIL...DAMAGING
WINDS AND TORNADOES ALL POSSIBLE. WILL NEED TO MONITOR THE
PROGRESS OF THE WARM FRONT AND HOW CLOSE TO THE REGION THE DRY
LINE GETS TODAY.
AS THE UPPER LEVEL TROUGH LIFTS OUT OF THE REGION FRIDAY NIGHT A
SECONDARY SLOW MOVING CUTOFF LOW OVER THE NORTHERN PLAINS WILL AID
IN DEVELOPING A SLIGHTLY SOUTHWESTERLY UPPER LEVEL FLOW OVER THE
WESTERN CONUS THROUGH THE WEEKEND. THIS WILL NOT ONLY HELP TO KEEP
THE FRONT WANDERING ACROSS MISSOURI BEFORE THE UPPER LOW LIFTS
NORTH SUNDAY NIGHT...IT WILL CONTINUE TO BRING UPPER LEVEL
MOISTURE INTO THE REGION THROUGH EARLY NEXT WEEK. THIS WILL KEEP
CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR THE
WEEKEND AND INTO TUESDAY OF NEXT WEEK.
THE REGION MAY SEE A BRIEF RESPITE FOR THE MIDDLE OF NEXT WEEK
BEFORE ANOTHER FRONT ATTEMPTS TO PUSH THROUGH THE OZARKS. THE
FRONT THEN LOOKS TO GET HUNG UP ACROSS MISSOURI AS UPPER LEVEL
RIDGING ATTEMPTS TO BUILD ACROSS THE SOUTHWESTERN CONUS FOR LATE
NEXT WEEK...RETURNING NORTHWEST UPPER FLOW OVER THE OZARKS.
HATCH
&&
.AVIATION...
/ISSUED 1209 PM CDT FRI APR 27 2012/
ACTIVE WEATHER WILL IMPACT AREA TERMINALS THIS AFTERNOON INTO
TONIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE OZARKS AND A STORM
SYSTEM APPROACHES FROM THE WEST. MVFR CEILINGS WILL IMPACT THE
TERMINALS AT TIMES THROUGH THIS EVENING. THUNDERSTORMS WILL
DEVELOP ACROSS SOUTHEAST KANSAS BY LATE THIS AFTERNOON THEN TRACK
EAST INTO THE OZARKS THIS EVENING. SOME OF THESE STORMS WILL BE
SEVERE.
GUSTY SOUTHEASTERLY WINDS WILL PERSIST AHEAD OF THE APPROACHING
FRONT WITH FREQUENT GUSTS OVER 25 KTS. MARGINAL LOW LEVEL WIND
SHEAR WILL BE POSSIBLE ESPECIALLY THIS EVENING. SURFACE WINDS WILL
SHIFT TO THE WEST LATE TONIGHT AS THE FRONT MOVES EAST ACROSS THE
REGION.
FOSTER
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1038 AM CDT FRI APR 27 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.UPDATE...
THE SEVERE WEATHER THREAT CONTINUES FOR THIS AFTERNOON AND
EVENING...ESPECIALLY FOR AREAS ALONG THE U.S. 71 CORRIDOR IN
SOUTHEASTERN KANSAS AND WESTERN MISSOURI.
A STRONG SHORTWAVE CONTINUES TO PUSH EAST OVER WESTERN KANSAS LATE
THIS MORNING...WITH AN ASSOCIATED WELL DEVELOPED AREA OF LOW
PRESSURE AT THE SURFACE. AS OF 15Z...A WARM FRONT STRETCHED FROM
NEAR WICHITA TO MIAMI OK TO LITTLE ROCK.
THE WARM FRONT/WARM SECTOR OF THIS SYSTEM SHOULD BEGIN TO
OVERSPREAD THE WESTERN PORTIONS OF THE CWA THIS AFTERNOON...LIKELY
MIXING NORTHEAST TO ROUGHLY U.S. 65 BY 00Z. I DO HAVE SOME CONCERN
AS TO WHETHER MODEL GUIDANCE IS UNDER-PLAYING THE SPEED OF THE
WARM FRONT...AS A COMBINATION OF STRONG PRESSURE AND HEIGHT
FALLS...ALONG WITH A BIT OF OCCASIONAL SUNSHINE NORTH OF THE WARM
FRONT...COULD RESULT IN VERY RAPID NORTHWARD MOVEMENT LATE THIS
AFTERNOON.
WHILE THE WARM SECTOR IS CURRENTLY QUITE CAPPED PER 12Z
RAOBS...A SERIES OF VORT MAXES WRAPPING AROUND THE MAIN UPPER
LOW/SHORTWAVE WILL ACT TO ERODE MUCH OF THAT INHIBITION BY 21Z. AT
THE SAME TIME...AN APPROACHING...AND PERHAPS SURGING...DRYLINE AND
COLD FRONT WILL APPROACH EASTERN KANSAS...SERVING AS THE FOCUS FOR
THUNDERSTORM DEVELOPMENT BETWEEN 18Z AND 21Z WEST OF THE CWA.
CELLS WILL LIKELY MOVE INTO THE U.S. 71 CORRIDOR BETWEEN 21Z AND
23Z. 12Z NAM AND 12/13Z RUC CONTINUE TO SUPPORT SUPERCELLS...WITH
AN ASSOCIATED RISK OF VERY LARGE HAIL...STRONG WINDS...AND
TORNADOES. THE TORNADO THREAT APPEARS TO BE MAXIMIZED ACROSS
EASTERN KANSAS AND THE WESTERN TIER OR TWO OF COUNTIES IN
MISSOURI...EXTENDING SOUTH INTO NORTHEASTERN OKLAHOMA. WITH STRONG
THERMODYNAMIC AND KINEMATIC PARAMETERS IN PLACE...AN ISOLATED
STRONG TORNADO CAN NOT BE RULED OUT ACROSS THIS AREA.
STORMS WILL CONTINUE TO PUSH EAST THIS EVENING TOWARD THE U.S. 65
CORRIDOR...THOUGH THE EASTERN EXTENT OF THE SEVERE WEATHER THREAT
REMAINS DEPENDENT ON HOW FAR THE WARM SECTOR BUILDS INTO MISSOURI.
THE OVERALL SEVERE THREAT LATE TONIGHT SHOULD BE MITIGATED A BIT
BY A COOLING/INCREASINGLY INHIBITED BOUNDARY LAYER...THOUGH
ISOLATED SEVERE STORMS WILL BE POSSIBLE THROUGH MIDNIGHT.
BOXELL
&&
.DISCUSSION...
MAIN CONCERNS FOR THE FORECAST PACKAGE FOCUS ON THE POTENTIAL FOR
SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING.
EARLY MORNING CONDITIONS ACROSS THE OZARKS AND SOUTHEASTERN
KANSAS HAVE DEWPOINTS IN THE 50S WITH TEMPERATURES IN THE 60S
NORTH OF A FRONT LAID OUT ACROSS CENTRAL ARKANSAS. THIS IS THE
COLD FRONT THAT MOVED THROUGH THE OZARKS YESTERDAY MORNING AND IT
WILL BEGIN TO MOVE ITS WAY NORTH AS A WARM FRONT TODAY AND BRING A
RETURN OF SOUTHERLY WINDS AND ADDITIONAL MOISTURE TO THE REGION.
THIS WILL BRING THE POTENTIAL FOR SEVERE WEATHER TO THE REGION
THIS AFTERNOON AND EVENING.
CURRENT SHORT TERM MODELS HAVE THE WARM FRONT LIFTING THROUGH THE
OZARKS THROUGH THE DAY TODAY AS SURFACE LOW PRESSURE NOW OVER
EASTERN COLORADO AND WESTERN KANSAS TRACKS EAST ACROSS THE PLAINS.
THIS WILL OCCUR IN RESPONSE TO THE UPPER LEVEL SHORT WAVE/CLOSED
LOW MOVING EAST. THE LEFT EXIT REGION OF A 250MB/500MB JET MAX WILL
BEGIN TO ROUND THE BEND OF THE UPPER TROUGH AND PROVIDE GOOD
DIFFLUENCE ALOFT. THIS WILL BE OCCURRING OVER A REGION OF
INCREASING INSTABILITY WITH MLCAPE VALUES VIA THE NAM UP TO AROUND
2000 J/KG...WITH 150 J/KG IN THE 0-3 KM LAYER. WHILE THE MODELS DO
TEND TO OVER DO THE LOW LEVEL CAPE...EVEN TAKING HALF OF THE
MODEL OUTPUT WOULD BE ENOUGH FOR SEVERE STORMS TO DEVELOP. THIS
WILL OCCUR IN CONJUNCTION WITH 0-3 KM BULK SHEAR AROUND 50-60
KTS AND 0-1 KM STORM RELATIVE HELICITY VALUES OVER 400M2/S2.
WOULD EXPECT THAT AREAS WEST OF HIGHWAY 65 IN GENERAL WILL HAVE
THE BEST CHANCES FOR SEVERE STORMS...WITH LARGE HAIL...DAMAGING
WINDS AND TORNADOES ALL POSSIBLE. WILL NEED TO MONITOR THE
PROGRESS OF THE WARM FRONT AND HOW CLOSE TO THE REGION THE DRY
LINE GETS TODAY.
AS THE UPPER LEVEL TROUGH LIFTS OUT OF THE REGION FRIDAY NIGHT A
SECONDARY SLOW MOVING CUTOFF LOW OVER THE NORTHERN PLAINS WILL AID
IN DEVELOPING A SLIGHTLY SOUTHWESTERLY UPPER LEVEL FLOW OVER THE
WESTERN CONUS THROUGH THE WEEKEND. THIS WILL NOT ONLY HELP TO KEEP
THE FRONT WANDERING ACROSS MISSOURI BEFORE THE UPPER LOW LIFTS
NORTH SUNDAY NIGHT...IT WILL CONTINUE TO BRING UPPER LEVEL
MOISTURE INTO THE REGION THROUGH EARLY NEXT WEEK. THIS WILL KEEP
CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR THE
WEEKEND AND INTO TUESDAY OF NEXT WEEK.
THE REGION MAY SEE A BRIEF RESPITE FOR THE MIDDLE OF NEXT WEEK
BEFORE ANOTHER FRONT ATTEMPTS TO PUSH THROUGH THE OZARKS. THE
FRONT THEN LOOKS TO GET HUNG UP ACROSS MISSOURI AS UPPER LEVEL
RIDGING ATTEMPTS TO BUILD ACROSS THE SOUTHWESTERN CONUS FOR LATE
NEXT WEEK...RETURNING NORTHWEST UPPER FLOW OVER THE OZARKS.
HATCH
&&
.AVIATION...
LOW LEVEL WIND SHEAR WILL PERSIST THIS MORNING AS A STRONG LOW
LEVEL JET STREAM SHIFTS OVER THE REGION. MEANWHILE...A WARM FRONT
WILL SHIFT NORTH TOWARDS THE AREA STARTING THIS MORNING. MVFR
CEILINGS ARE EXPECTED TO DEVELOP AHEAD OF THE FRONT...AS WELL AS
SCATTERED SHOWERS AND THUNDERSTORMS. STRONG AND GUSTY SOUTHEAST
WINDS WILL ALSO DEVELOP...WITH GUSTS OVER 30 KNOTS LIKELY INTO
THIS AFTERNOON. WE WILL THEN GET A BREAK IN THE PRECIPITATION AND
MVFR CEILINGS LATER THIS AFTERNOON. SCATTERED STRONG TO SEVERE
THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP ACROSS SOUTHEASTERN
KANSAS AND WESTERN MISSOURI FROM LATE THIS AFTERNOON INTO THIS
EVENING. WITH TIMING SOMEWHAT IN QUESTION...WENT WITH A PREVAILING
VCTS GROUP FOR NOW AT KJLN AND KSGF. MOST IF NOT ALL ACTIVITY IS
EXPECTED TO REMAIN NORTH OF KBBG.
SCHAUMANN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1055 PM MDT THU APR 26 2012
UPDATED AVIATION SECTION
.UPDATE...
EXTREME SHORT RANGE MODELS INCLUDING THE HRRR AND RUC HAVE MOVED
INTO TIGHT AGREEMENT WITH LATEST NAM AND GFS RUNS SHOWING A
SIGNIFICANTLY HIGHER AMOUNT OF MOISTURE OVER THE MOUNTAINS OF
SOUTHWEST MONTANA TONIGHT. DUE TO THE SIGNIFICANTLY SHORT
TIME FRAME HAVE MADE THE NONTRADITIONAL DECISION TO UPGRADE THE
WINTER STORM WATCH TO A WARNING THIS EVENING WITH THIS NEW DATA.
DUE TO THE INCREASED CONFIDENCE FOR THE POTENTIAL OF SIGNIFICANT
IMPACTS BEFORE THE NEXT STANDARD FORECAST SUITE UPDATE. THE
WARNING IS IN EFFECT FOR ELEVATIONS ABOVE 6500 FEET...WITH NO
ADVISORY BELOW 6500 FEET DUE TO THE WARMER TEMPERATURES EXPECTED
IN THE VALLEY LOCATIONS OF THE SOUTHWEST TONIGHT. THESE ARE THE
EXPECTED CONDITIONS AT THIS TIME...HOWEVER THERE IS A SLIGHT
POSSIBILITY THAT SNOW ACCUMULATIONS COULD MAKE IT DOWN INTO THE
LOWER ELEVATIONS AND ADDITIONAL HIGHLIGHTS MAY BECOME NECESSARY.
WITH THIS UPDATE...THE IMPACTS FOR LOCATIONS OUTSIDE OF SOUTHWEST
MONTANA LOOK LESS IMPRESSIVE AND DECIDED TO DELAY THE WINTER
WEATHER WATCH UNTIL 1800Z FRIDAY. SUK
&&
.AVIATION...
UPDATED 2355Z.
A STORM SYSTEM WILL KEEP THE WEATHER ACTIVE ACROSS THE AREA THROUGH
THE TAF PERIOD. SCATTERED SHOWERS WILL CONTINUE THIS EVENING AS A
COLD FRONT PASSES THROUGH THE AREA. THUNDERSTORMS COULD AFFECT KLWT
AND KHVR BEFORE 09Z. WESTERLY WINDS WILL INCREASE ACROSS THE AREA
OVERNIGHT AND INTO FRIDAY ALONG WITH AREAS OF PRECIPITATION AND
LOWER CEILINGS... RESULTING IN MVFR CONDITIONS BY LATE IN THE
AFTERNOON. MOUNTAINS WILL BE OBSCURED THROUGH THE TAF PERIOD.
LANGLIEB
&&
.PREV DISCUSSION...
/ISSUED 555 PM MDT THU APR 26 2012/
TODAY THROUGH SATURDAY EVENING...FORECAST STILL ON TRACK FOR PAIR OF
VERY MOIST PACIFIC WEATHER SYSTEMS TO BRING WIDESPREAD AND LONG
DURATION PRECIPITATION ALONG WITH MUCH COOLER TEMPERATURES OVER OUR
REGION THROUGH THE ENTIRE SHORT-TERM FORECAST AREA. CURRENT
SATELLITE IMAGERY SHOWS THE SLIGHTLY WEAKER SYSTEM NOW IN ARIZONA
AND BEGINNING TO LIFT NORTHEASTWARD. MEANWHILE...THE MUCH DEEPER
UPPER LEVEL TROF IS CLOSING IN ON THE WA/OR COAST AND IS EXPECTED TO
MOVE INLAND TONIGHT. ASSOCIATED MOISTURE PLUME WITH THESE SYSTEM
COVERS A BROAD AREA OF THE GREAT BASIN AND NRN ROCKIES WITH
ADDITIONAL MOISTURE EXPECTED TO ACCOMPANY THE STRONGER TROF. AS OF
230 PM LEADING EDGE OF THE MOISTURE IS LOCATED IN OVER OUR FORECAST
AREA WHERE IT HAS BEGUN TO MIX WITH LIFT AND INSTABILITY TO GENERATE
ISOLATED SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST AND CENTRAL
MT. EXPECT THIS ACTIVITY TO BROADEN IN COVERAGE THIS AFTN/EVE BUT
INSTABILITY WILL WEAKEN AFTER SUNSET SO SHOWERS WILL CONTINUE BUT
THUNDERSTORMS SHOULD DISSIPATE. BEST NEWS IN THE OUTLOOK IS THAT
PRIMARY SHORT-TERM FORECAST MODELS ARE IN MUCH BETTER AGREEMENT ON
CONDITIONS FOR TOMORROW AND SATURDAY...CERTAINLY BETTER THAN THE
GLARING DIFFERENCES SEEN THE PAST FEW DAYS. THE TWO WEATHER SYSTEMS
WILL CONTINUE TO TRACK TOWARD EACH OTHER AND EVENTUALLY MERGE OVER
NORTHERN WYOMING LATE FRI...THEN GRADUALLY LIFT INTO FAR SOUTHEAST
MT ON SAT. AS IT DOES SO...ADDITIONAL MOISTURE WILL BE PULLED FROM
THE DAKOTAS OVER THE NRN FLANK OF THE CLOSED LOW PRESSURE
AREA...KEEPING A NEAR CONTINUOUS PERIOD OF RAIN...RAIN/SNOW
MIX...AND SNOW GOING THROUGH SATURDAY. MODELS STILL SHOW SOME
SLIGHT VARIATIONS IN TOTAL PRECIPITATION AND AMOUNTS BUT
GENERALLY EXPECT ONE-HALF TO THREE-QUARTERS OF AN INCH OVER MUCH OF
THE REGION. SNOW WILL DEVELOP OVER THE SOUTHWEST MTNS TONIGHT AND
GRADUALLY SPREAD INTO THE HIGHER ELEVATIONS OF CENTRAL MT FRI PM-SAT
AM. SNOW LEVELS WILL GRADUALLY DROP THROUGH SATURDAY SO A FEW
INCHES OF WET SLUSH ARE POSSIBLE AT ELEVATIONS AROUND 3000 FT WITH
SIGNIFICANTLY HIGHER SNOW AMOUNTS FOR THE CENTRAL MTN RANGES. THUS
CURRENT WINTER WEATHER WATCH FOR ALL BUT OUR NORTHEAST ZONES REMAINS
IN EFFECT AND BEGINS AT MIDNIGHT TONIGHT.
GIVEN THE EXPECTED PRECIP AMOUNTS...RIVERS AND STREAMS WILL CONTINUE
TO RISE. A FEW CREEKS IN GLACIER COUNTY ARE ALREADY NEAR
BANKFULL...SO HAVE ISSUED A SMALL STREAM FLOOD ADVISORY THERE.
FURTHER DETAILS ARE IN THE HYDROLOGY SECTION BELOW.
WARANAUSKAS
SATURDAY NIGHT THROUGH THURSDAY...MODERATE AGREEMENT IN MODEL
GUIDANCE REGARDING THE TIMING AND LOCATION OF THE UPPER LEVEL LOW AS
IT MOVES OUT OF THE REGION. CURRENT FORECAST FAVORS THE GFS SOLUTION
AND KEEPS RESIDUAL MOISTURE AROUND AS THE GFS IS SLOWER TO PUSH THE
SYSTEM NORTHEASTWARD. PRECIPITATION SHOULD BE LIGHT AND REMAIN AS
RAIN...POSSIBLY A RAIN SNOW MIX...IN THE LOWER ELEVATIONS WITH SNOW
IN THE MOUNTAINS. A MORE ZONAL FLOW DEVELOPS EARLY NEXT WEEK AND
WILL PERSIST THROUGH WEDNESDAY. A SHORTWAVE WILL MOVE OVER THE AREA
MONDAY EVENING BRINGING A CHANCE OF PACIFIC MOISTURE...MAINLY TO THE
ROCKY MOUNTAIN FRONT AND SW MONTANA...AND THEN AGAIN ON TUESDAY
EVENING AFFECTING THE SAME AREAS. BY WEDNESDAY AFTERNOON EXPECT
CLEARING AND THE FLOW TO BECOME MORE SOUTHWESTERLY. TEMPERATURES
WILL START OFF A LITTLE COOL ON SUNDAY AND APPROACH SEASONAL
AVERAGES THE REMAINDER OF THE PERIOD. MERCER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 39 50 33 47 / 80 60 70 70
CTB 34 48 31 49 / 90 60 70 70
HLN 36 48 32 49 / 90 50 60 60
BZN 31 46 23 46 / 90 80 60 60
WEY 27 35 18 37 / 100 80 70 60
DLN 30 43 24 46 / 100 70 50 50
HVR 38 51 33 45 / 80 70 80 60
LWT 35 47 30 41 / 90 70 70 70
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY
AFTERNOON BROADWATER...CASCADE...CENTRAL AND SOUTHERN LEWIS AND
CLARK...CHOUTEAU...EASTERN GLACIER...EASTERN PONDERA...EASTERN
TETON...FERGUS...JEFFERSON...JUDITH BASIN...MEAGHER...NORTHERN
ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT.
WINTER STORM WARNING UNTIL NOON MDT FRIDAY FOR ELEVATIONS ABOVE
6500 FEET FOR BEAVERHEAD...GALLATIN...MADISON.
SMALL STREAM FLOOD ADVISORY FOR GLACIER COUNTY UNTIL NOON SATURDAY.
&&
$$
SHORT TERM...SUK
LONG TERM...MERCER
AVIATION...LANGLIEB
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1135 PM CDT THU APR 26 2012
.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. SPOTTY SHOWERS OR
SPRINKLES MOVING THROUGH THE KOMA/KOFK CURRENTLY AND WILL LIKELY
BE OVER BY ABOUT 08Z. THEN THERE WILL BE A SEVERAL HOUR BREAK
BEFORE PRECIPITATION MOVES BACK IN LATER ON MONDAY MORNING. THERE
WILL ALSO BE SOME LOW LEVEL WIND SHEAR AT ALL TAF SITES THROUGH
LATER THIS MORNING AS WELL...WITH EAST SOUTHEAST SURFACE WINDS
INCREASING TO 18 TO 22 KTS SUSTAINED WITH HIGHER GUSTS. RAIN
MOVES BACK INTO THE KOFK BY 15Z...KLNK BY 17Z AND KOMA BY 18Z WITH
MVFR CEILINGS DEVELOPING. THERE COULD BE SOME THUNDERSTORMS ALONG
THE NE/KS BORDER REGION LATER SATURDAY AFTERNOON AND EVENING BUT
SHOULD REMAIN SOUTH OF THE KLNK TAF SITE. AS LOW PRESSURE MOVES TO
NEAR KSTJ LATE IN THE TAF PERIOD...WINDS WILL LIKELY SWITCH TO THE
NORTH...BUT DID NOT ADD IN ADDITIONAL GROUPINGS THAT FAR OUT.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 915 PM CDT THU APR 26 2012/
DISCUSSION...
FIRST BAND OF LIGHT SHOWERS OR SPRINKLES IS MOVING INTO WESTERN
PORTIONS OF THE FORECAST AREA. RAIN IS REACHING THE GROUND IN
NORTHEAST NEBRASKA WHERE DBZ RETURNS HAVE BEEN SLIGHTLY HEAVIER.
STILL SOME DRY AIR AT THE SURFACE WHICH HAS TO BE OVERCOME FIRST.
FURTHER SOUTH OF COLUMBUS TOWARD BEATRICE...PROBABLY NOTHING MORE
THAN A FEW SPRINKLES THERE. THIS BAND WILL CONTINUE TO PUSH
EASTWARD THIS EVENING...AND COULD LIKELY STILL SEE SOME SPRINKLES
MOVE TOWARD THE REMAINDER OF EASTERN NEBRASKA TOWARD THE MISSOURI
RIVER.
BELIEVE THERE WILL PROBABLY BE A BREAK IN THE PRECIPITATION BEHIND
THIS INITIAL BAND. REGIONAL RADAR MOSAIC SHOWS A LOT OF PRECIP
FREE AREAS ACROSS CENTRAL KANSAS AND CENTRAL KANSAS...WHICH BOTH
THE 21Z SREF AND 00Z NAM PICKED UP ON. ADJUSTED POPS OVERNIGHT TO
ACCOUNT FOR THAT...ALTHOUGH STILL LEFT IN A SLIGHT CHANCE FOR
MAINLY A SPRINKLE. THE MAIN AREA OF STEADIER RAIN/SHOWERS DOES
SPREAD ACROSS THE FORECAST AREA FRIDAY MORNING...BUT PERHAPS JUST
A COUPLE HOURS SLOWER THAN PREVIOUSLY THOUGHT.
DEWALD
PREV DISCUSSION... /ISSUED 348 PM CDT THU APR 26 2012/
SHORT TERM...TONIGHT.
THE MAIN FORECAST CONCERN TONIGHT WILL BE THE CHANCE FOR SHOWERS.
THE CLOUDS WILL CONTINUE TO THICKEN THIS EVENING AS THE FIRST
AREA OF LIFT MOVES ACROSS THE FORECAST AREA. THE SHORT TERM MODELS
DO NOT HAVE A REAL GOOD HANDLE ON THE PRECIP FROM WESTERN NEBRASKA
INTO KANSAS...ALTHOUGH MOST OF THIS IS LIGHT. THE GFS WAS DOING
THE BEST AND THE 15Z SREF BETTER THAN THE 09Z SREF. THE HRRR HAS
SOME PRECIP UP TO THE CWA...THEN DISSIPATES IT THIS EVENING WITH
SOME INCREASE IN THE NORTHEAST PART OF THE FORECAST AREA AFTER
06Z.DUE TO THE DRY AIR IN PLACE...THERE MAY BE A FEW SHOWERS OR
SPRINKLES...WITH THE BEST CHANCE FOR SOME MINOR PRECIP
ACCUMULATIONS IN THE WEST OF WAYNE AND LINCOLN AND SPRINKLES
FARTHER EAST. DID NOT MENTION THUNDER AS BOTH THE NAM/GFS TENDED
TO KEEP THE BETTER INSTABILITY IN THE WESTERN PART OF THE CWA OR
TO THE WEST TONIGHT. SOUTHEAST WINDS LOOK TO INCREASE INTO THE 15
TO 30 MPH RANGE OVERNIGHT.
ZAPOTOCNY
LONG TERM...SATURDAY THROUGH THURSDAY.
PRECIPITATION CHANCES WILL PROVIDE THE MAIN FORECAST CHALLENGES
THROUGH THE EARLY PART OF THIS PERIOD.
500 MB CHART FROM THIS MORNING SHOWED A STRONG AND COMPACT CLOSED
LOW JUST WEST OF SAN DIEGO. THIS FEATURE HAD 12 HOUR HEIGHT FALLS
OF AROUND 170 METERS. IT WILL CONTINUE TO TRACK QUICKLY NORTHEAST
AND SHOULD BE OVER THE EASTERN COLORADO/NORTHWEST KANSAS BORDER
AREA BY 12Z FRIDAY. AS THIS FEATURE LIFTS OUT INTO THE CENTRAL
PLAINS FRIDAY...EXPECT FAIRLY WIDESPREAD PRECIPITATION TO OCCUR.
LOW LEVELS WILL BE SLOW TO SATURATE...WITH MAIN 850 MB MOISTURE
AND INSTABILITY AXIS GENERALLY REMAINING WEST AND SOUTH OF THE
FORECAST AREA. 12Z GFS SHOWED 850 DEWPOINTS REACHING 10-12
DEGREES CELCIUS IN PARTS OF SOUTHEAST NEBRASKA DURING THE DAY.
CAN NOT RULE OUT A FEW STORMS INTO THAT AREA...BUT MAIN SEVERE
THREAT SHOULD STAY TO OUR SOUTH FRIDAY. TEMPERATURES WILL BE COOL
WITH EASTERLY WINDS...CLOUDS AND PRECIPITATION. GENERALLY STAYED
BELOW MOS GUIDANCE FOR HIGHS FRIDAY.
KEPT FAIRLY HIGH RAIN CHANCES FRIDAY NIGHT AND SOME THUNDERSTORMS
STILL SEEM POSSIBLE IN THE EVENING...ESPECIALLY OVER SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA. FAIRLY STRONG DRYING TAKES PLACE
BEHIND THE MAIN SHORTWAVE TROUGH BY LATE FRIDAY NIGHT SO EXPECT
SATURDAY TO BE MOSTLY DRY. THE 12Z ECMWF AND 12Z GFS MODEL SOLUTIONS
START TO DIVERGE BY SATURDAY NIGHT INTO SUNDAY. GFS IS MORE
AGGRESSIVE WITH PRECIPITATION SPREADING BACK INTO THE AREA FROM
THE SOUTH. GENERALLY FELT THE ECMWF WAS HANDLING THE PATTERN
BETTER THAN THE GFS...BUT COULD NOT RULE OUT GFS SOLUTION SO
BLENDED SOME OF THAT THINKING INTO GRIDS. A DIFFERENT CLOSED
LOW...ASSOCIATED WITH THE TROUGH CURRENTLY OFF THE PACIFIC
NORTHWEST...WILL MOVE INTO NORTHERN WYOMING OR SOUTHERN MONTANA BY
00Z SATURDAY. THIS SHOULD TRACK EAST TOWARD THE WESTERN DAKOTAS
THROUGH SATURDAY EVENING AND THEN LIFT NORTH THROUGH SUNDAY NIGHT.
MAIN AFFECTS FROM THAT SHOULD STAY TO OUR WEST OR SOUTH.
A WEAK TROUGH REMAINS OVER THE ROCKIES THROUGH MID WEEK...WITH
SEVERAL RIPPLES IN THE FLOW MOVING OUT ACROSS OUR AREA. THE TIMING
DIFFERENCES PERSIST THROUGH DAY 7.
MILLER
AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE FORECAST THROUGH 27/15Z. FIRST PIECE OF ENERGY
WILL LIFT ACROSS THE TAF SITES THIS AFTERNOON. MID LEVEL CLOUDS
WILL BE ON THE INCREASE MOSTLY AT FL100...BUT ALSO SOME SCT-BKN AT
FL050. DRY AIR SHOULD LIMIT WIDESPREAD PRECIPITATION. THERE MAY BE
A FEW SPRINKLES OR SHOWERS...HOWEVER DUE TO SPOTTY NATURE HAVE NOT
INCLUDED. THE STRONGER PIECE OF ENERGY WILL MOVE ACROSS THE AREA
FRIDAY. DEEP MOISTURE WILL BE AVAILABLE WITH STRONGER LIFT AND
MORE WIDESPREAD PRECIPITATION ALONG WITH LOWER MVFR CIGS POSSIBLE.
NORTHEAST WINDS WILL BECOME EAST AT 10 TO 15KTS WITH SOME GUSTS 20
TO 25KTS. TONIGHT AFTER 06Z...EAST TO SOUTHEAST WINDS WILL
INCREASE TO 15 TO 25KTS WITH GUSTS 25 TO 30KTS. MENTIONED LOW
LEVEL WIND SHEAR AT KOMA AND KLNK AFT 09Z WITH 2K WINDS INCREASING
TO 45 TO 55KTS.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
259 PM EDT FRI APR 27 2012
.SYNOPSIS...
THE COLD NORTHWEST FLOW WILL CONTINUE INTO THIS EVENING WITH
PERHAPS A LEFTOVER SPRINKLE OF FLURRY. CLEARING SKIES LATER
TONIGHT WILL ALLOW TEMPERATURES TO FALL INTO THE 20S. SATURDAY
WILL START OUT SUNNY UNDER HIGH PRESSURE BUT A LOW PRESSURE SYSTEM
MOVING TO OUR SOUTH MAY BRING SOME HIGH CLOUDS BACK INTO THE AREA
LATE IN THE DAY. THIS SYSTEM MAY BRING SOME LIGHT RAIN OR MIXED
PRECIPITATION SATURDAY NIGHT OVER NORTHEAST PENNSYLVANIA.
&&
.NEAR TERM /THROUGH TONIGHT/...
SO THE QUESTION FOR THE NEAR TERM IS THIS: HOW MUCH WILL WE CLR
OUT? AS USUAL...A DFCLT CALL WITH EARLIER RUNS SHWG CLRG BY THIS
AFTN. LATEST NAM FCST STEADFASTLY PREDICTS CLRG THIS EVE WHILE THE
RUC STUBBORNLY KEEPS CLDS OVER MUCH OF CNTRL NY THRU 12Z. CLRG
OVER WRN PA HAS STOPPED MAKING PROGRESS EWRD THIS AFTN. WILL HEDGE
TWRD THE CDY RUC FOR THIS EVE...BUT FCST CLRG LTR IN THE EVE. THIS
WLD NRMLY PRESENT PROBLEMS FOR THE FREEZE ADVISORY WITH THE CLDS
LIMITING THE TEMP FALLS. HWVR...WE JUST NOW HAVE FNLY RISEN ABV
FRZG HERE AT BGM SO IT/S NOT LIKE WE HAVE ALL THAT FAR TO FALL.
WILL CONT WITH THE WARNING. ONLY OTR WX ISSUE IS THE LGT SHWRS OF
RAIN AND SNOW OVER NY. RADAR TREND SHOWS A SLOW WEAKENING OF THE
PCPN SO WILL CONT THE TREND WHILE KEEPING LGT PCPN FOR THE NEXT
FEW HRS...WITHDRAWING THE PCPN AREA TO THE NORTH.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
SFC HIPRES NOSES IN SAT AND BRIGS MAINLY CLR SKIES AND ALLOWS FOR
A RECOVERY ON TEMPS BEFORE HI CLDS RETURN FROM THE SOUTH LATE IN
THE DAY.
MODELS COMING INTO AGREEMENT ON THE WV PASSING SOUTH OF THE AREA
LATE SAT AND EARLY SUN. NAM HAD JUMPED NWRD WITH THE WV AND PCPN
BUT HAS NOW RETREATED SWRD NEAR THE GFS SOLN. GFS IS A BIT FASTER
WITH THE PCPN BUT BOTH MODELS JUST BRUSH THE SRN ZONES MAINLY AFT
00Z SUN. PCPN TYPE ANALYSIS SUGGESTS RAIN TO START BUT A
TRANSITION OVER TO SOME LGT SNOW LATE AS THE TROF PASSES.
1028MB HI BLDS INTO THE LAKES BHD THE WV AND BRINGS COLD AND DRY
AIR FOR SUN AND MON. THIS WILL NO DOUBT RESULT IN VERY CHILLY
NGTS WITH MINS WELL DOWN INTO THE 20S AND RESULTING CONTINUENCE OF
THE FREEZE WARNING
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
11 AM UPDATE...
FOLLOWED HPC GUIDANCE. ZONAL FLOW WITH TWO SYSTEMS GOING THROUGH
DURING THE PERIOD. CHANCE OF RAIN SHOWERS EACH PERIOD WITH
TEMPERATURES SLIGHTLY ABOVE NORMAL.
MODELS SIMILAR. WEAK FIRST SYSTEM COMES IN LATE MONDAY NIGHT WITH
SHOWERS AND CONTINUES INTO TUESDAY NIGHT. TRACK OF THE SURFACE LOW
JUST TO THE SOUTH. MAY BE A BREAK WEDNESDAY BUT WILL BE BRIEF AS
SECOND LARGER AND STRONGER SYSTEM MOVES INTO THE MIDWEST WED. A
WARM FRONT PUSHES INTO THE AREA LATE WEDNESDAY. THIS SURFACE LOW
TRACKS SLOWLY ENE ACROSS THE WESTERN GREAT LAKES INTO SE CANADA
FRIDAY. MULTIPLE COLD FRONTS FRIDAY TO SATURDAY. AS USUAL THE GFS
IS SLIGHTLY FASTER BUT NOT THAT MUCH DIFFERENCE FOR DAY 7.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
18Z FRI UPDATE... MVFR RESTRICTIONS ARE LIKELY TO CONTINUE AT
KITH/KBGM TIL LATE AFTN (20-22Z). OTHERWISE...VFR CIG BASES ARE
ANTICIPATED (3500-4500 FT AGL). DURG THE EVE (00-03Z)...DRIER AIR
SHOULD FINALLY WORK IN AT LOWER-LEVELS...LEADING TO CLEARING
SKIES. GUSTY NW WINDS THIS AFTN AND EARLY EVE...SHOULD DIMINISH TO
UNDER 10 KT BY 01-02Z.
SAT...VFR EXPECTED THROUGH 18Z...WITH NW WINDS ONLY 5-10 KT.
.OUTLOOK...
SAT...MAINLY VFR. A LOW PROBABILITY OF MVFR RESTRICTIONS AT KAVP
IN THE LATE AFTN/EARLY EVE PD.
SUN-MON...VFR.
TUE INTO WED...RESTRICTIONS POSSIBLE...AS SCTD -SHRA COULD DEVELOP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT SATURDAY
FOR PAZ038>040-043-044-047-048-072.
NY...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT SATURDAY
FOR NYZ009-015>018-022>025-036-037-044>046-055>057-062.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...MLJ
AREA FORECAST DISCUSSION...CORRECTED
NWS WILMINGTON NC
824 PM EDT SAT APR 28 2012
.SYNOPSIS...
A COLD FRONT WILL MEANDER ABOUT THE REGION THROUGH EARLY MONDAY. A
SUMMERTIME PATTERN WILL THEN DEVELOP AND CONTINUE THROUGH THE
REMAINDER OF THE PERIOD.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 8:00 PM SATURDAY...SHOWERS DEVELOPED LATE THIS AFTERNOON AT
THE INTERSECTION OF THE SEA BREEZE FRONT AND THE STALLED FRONT
OVER SOUTHERN MARION COUNTY AND WEST-CENTRAL HORRY COUNTY. THESE
SHOWERS FADED WITH THE SETTING SUN AND BASED ON LATEST GUIDANCE
EXPECT A QUIET NIGHT AHEAD. MINOR TWEAKS TO THE GRIDDED DATABASE
TO ADJUST THE TEMPERATURE CURVE IN SOME LOCATIONS. FORECAST
REMAINS ON TRACK. PREVIOUS DISCUSSION FOLLOWS:
CLOUDS ALONG AND NORTH OF THE STALLED FRONT HAVE BEEN EXCEEDINGLY
RESILIENT TO BURNING OFF DESPITE RELATIVELY STEEP LATE-APRIL SUN
ANGLES AND THE LACK OF PRECIPITATION. WITH THE SUN ALREADY PASSING
INTO THE WESTERN SKY WE HAVE TO ENTERTAIN THE NOTION THAT CLOUDS
WILL PERSIST SOLIDLY THROUGH SUNSET IN THE LUMBERTON AND
BENNETTSVILLE AREAS WITH HIGHS PERHAPS REACHING THE LOWER 70S
BEFORE FALLING AGAIN THIS EVENING. THE FRONT HAS BECOME
CONCOMITANT WITH THE SEABREEZE AT THE COAST AND APPEARS TO LIE
ALONG A LINE FROM SOUTHPORT TO GREEN SEA TO MARION AND FLORENCE.
THE BOUNDARY WILL SLOWLY MOVE NORTH TONIGHT...FINALLY LIFTING
THROUGH LUMBERTON AROUND MIDNIGHT. EAST TO NORTHEAST WINDS ON THE
COOL SIDE OF THE BOUNDARY WILL TURN SOUTHERLY. THERE SHOULD NOT BE
AN INCREASE IN WIND SPEEDS DOWN HERE AT THE SURFACE BEHIND THE
FRONT DUE TO ONLY A WEAK LOW LEVEL JET ALOFT...15-20 KT IN THE
1000-2000 FT LAYER. THIS WILL HOPEFULLY BE JUST ENOUGH WIND TO
PREVENT WIDESPREAD FOG DEVELOPMENT BUT WILL INSTEAD FAVOR THE
FORMATION OF LOW STRATUS CLOUDS AFTER MIDNIGHT.
ALTHOUGH SPC AND RUC MESO ANALYSIS SHOW SURFACE-BASED CAPE ON THE
ORDER OF 1000-1500 J/KG ACROSS INLAND SOUTH CAROLINA...DRY
ENVIRONMENTAL CONDITIONS BETWEEN THE LCL AND LFC AND THE NOTABLE
LACK OF ANY UPPER AIR IMPULSES MEAN THERE IS ONLY A TINY CHANCE
FOR A SHOWER OR THUNDERSTORM TO FORM BETWEEN NOW AND SUNSET. IF
ANYTHING WERE TO FORM IT WOULD LIKELY BE NEAR THE INTERSECTION OF
THE SEABREEZE AND THE SYNOPTIC FRONT...SOMEWHERE FROM MARION AND
TABOR CITY TO LAKE WACCAMAW. LOWS TONIGHT SHOULD FALL INTO THE
LOWER TO MID 60S...7-10 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3:00 PM SATURDAY...THE PERSISTENT BAROCLINIC ZONE WILL
CONTINUE TO BE AN ISSUE THROUGH THE PERIOD AS IT MAKES ANOTHER RUN
TO THE SOUTH LATER SUNDAY AS THE MID LEVEL RIDGE AMPLIFIES ACROSS
THE MIDWEST. FORECAST CHALLENGE WILL PRIMARILY BE POPS.
FOR SUNDAY...MIXED LAYER CAPE VALUES INCREASE TO APPROXIMATELY
2000K J/KG PER THE GFS ACROSS NORTHERN ZONES AS THE FRONT SLIPS
SOUTH. THIS INSTABILITY ALONG WITH THE FORCING WITH A SUBTLE
SHORTWAVE THROWN IN FOR GOOD MEASURE WARRANTS LOWER CHANCE POPS
FOR THESE AREAS LATE SUNDAY INTO THE EVENING HOURS.
POPS DIMINISH WITH THE LOSS OF DAYTIME HEATING SUNDAY NIGHT INTO
EARLY MONDAY BUT THE OVERCAST SKIES...MOISTURE TRAPPED UNDER A
CONSIDERABLE SUBSIDENCE INVERSION WILL CONTINUE TO INCREASE
SOUTHWARD.
MONDAY IS A TRANSITION DAY AS THE FRONT DISSIPATES AS THE
SOUTHERLY FLOW DEVELOPS. HOWEVER THIS WILL TAKE SOME TIME AND THE
INVERSION REMAINS PRESENT MOST OF THE DAY AND ALTHOUGH THE GFS AND
NAM ARE DEVELOPING A LITTLE LIGHT QPF...INDICATIONS ARE THIS IS
THE AFOREMENTIONED MOISTURE/STRATUS DECK.
TEMPERATURE GUIDANCE HAS WARMED SLIGHTLY AND THE MAIN CHALLENGE
APPEARS TO BE MONDAY MORNING LOWS AS THE CLOUD COVER WILL BE
INCREASING AND IT APPEARS THE BEST STRATEGY WILL BE TO ADD A
DEGREE OR TWO TO THE NUMBERS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3:00 PM SATURDAY...CONDITIONS WILL REMAIN LARGELY RAIN-FREE
THROUGH THE LONG TERM AS AN UPPER LEVEL RIDGE AXIS BUILDS ACROSS
THE EAST COAST. SURFACE HIGH PRESSURE WILL SIMILARLY SHOW LITTLE
MOVEMENT ACROSS THE WEST ATLANTIC. THIS LATTER FEATURE WILL IMPORT
WARM AND MOIST AIR ACROSS THE SOUTHEASTERN U.S. LEADING TO
SLIGHTLY WARM TEMPERATURES BY DAY AND EVEN MORESO WARMTH DURING
THE NIGHTTIME HOURS AS MOISTURE ACTS AS A LIMITING FACTOR FOR
COOLING. THIS LOW LEVEL MOISTURE PAIRED WITH THE WARM WILL AT SOME
POINT TRY TO START FIRING DIURNAL CONVECTION ALONG THE SEA BREEZE.
THE SUBSIDENCE ASSOCIATED WITH THE RIDGING ALOFT WILL KEEP THIS
ACTIVITY ISOLATED ENOUGH TO PRECLUDE BEING PUT IN THE FORECAST AT
THIS TIME HOWEVER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...A STATIONARY FRONT WAS LOCATED JUST TO THE SOUTH OF
THE TERMINALS. AN UPPER IMPULSE WILL APPROACH OVERNIGHT...BUT
SHOULD PASS WELL TO THE NORTH. AS IT APPROACHES THE FRONT WILL
BEGIN TO MOVE SLOWLY NORTH THROUGH THE TERMINALS. AS THE UPPER
IMPULSE PASSES THE FRONT SHOULD MOVE BACK TO THE SOUTH AT LEAST
THROUGH THE ILM/LBT TERMINALS BY AFTERNOON.
THE MAIN FORECAST CONCERN WILL BE MVFR/IFR STRATUS/FOG POTENTIAL
THIS EVENING AND OVERNIGHT. FEEL THE BEST IFR FOG POTENTIAL WILL
BE AT THE FLO/LBT TERMINALS BY 06Z. AFTER MIDNIGHT INCREASING
MID-LEVEL CLOUD COVER AND INCREASING BOUNDARY LAYER WINDS SUGGEST
VISIBILITIES MAY IMPROVE...BUT AN IFR STRATUS LAYER WILL LIKELY DEVELOP.
AT THE COASTAL TERMINALS MVFR/TEMPO IFR CEILINGS WILL BE LIKELY
THIS EVENING...WITH THE BEST IFR POTENTIAL AFTER MIDNIGHT.
VFR EXPECTED AFTER 13-15Z AT ALL TERMINALS. WINDS WILL BECOME LIGHT
SOUTHWEST OVERNIGHT...THEN BECOME WEST TO WEST-NORTHWEST AFTER
SUNRISE. BY AFTERNOON WINDS WILL BECOME SOUTH...EXCEPT NORTHEAST TO
EAST NORTHEAST LBT AND EAST TO EAST-SOUTHEAST AT ILM. ISOLATED SHOWERS
ARE POSSIBLE FROM LBT TO ILM ALONG THE FRONT DURING THE AFTERNOON.
EXTENDED OUTLOOK...A SLIGHT CHANCE OF MVFR/SHOWERS THROUGH TUESDAY.
LOW CONFIDENCE IFR VSBYS IN MORNING FOG TUESDAY AND WEDNESDAY.
MODERATE CONFIDENCE SCATTERED THUNDERSTORMS THURSDAY NORTHERN
TERMINALS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 8:00 PM SATURDAY...STALLED FRONT NOW BISECTING THE WATERS IN
THE CAPE FEAR VICINITY...WITH LIGHT AND VARIABLE WINDS OVER MOST
OF OUR WATERS AT THIS TIME. SEA BREEZE FROM THIS AFTERNOON HAS
FADED ALTHOUGH WINDS ARE STILL ONSHORE WITHIN A FEW MILES OF THE
COAST. HAVE ADDED VARIABLE WIND VERBIAGE TO THE FORECAST FOR EARLY
ON THIS EVENING...OTHERWISE FORECAST REMAINS UNCHANGED FROM
PREVIOUS DISCUSSION BELOW:
THE FRONT HAS MOVED VERY LITTLE DURING THE DAYLIGHT HOURS...STILL
STALLED FROM THE CAPE FEAR VICINITY INLAND ACROSS EXTREME NORTHERN
SOUTH CAROLINA. THE AFTERNOON SEABREEZE HAS MADE PRECISE FRONTAL
ANALYSIS DIFFICULT WHERE SOUTHEAST WINDS HAVE DEVELOPED NEAR THE
COAST. MODELS ARE ALMOST UNANIMOUS WITH THEIR DEPICTIONS OF THE
FRONT MOVING SLOWLY NORTH TONIGHT...FINALLY REACHING TOPSAIL
ISLAND A FEW HOURS AFTER SUNSET. SOUTH WINDS WILL OVERSPREAD THE
AREA WITH SPEEDS INCREASING TO 10-15 KT. IT APPEARS DRY WEATHER
WILL CONTINUE THROUGH THE NIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3:00 PM SATURDAY...INITIALLY WINDS WILL CONTINUE FROM THE
SOUTHWEST ACROSS ALL WATERS AND WITH THE RESULTANT SEA BREEZE
BACKING WINDS LATE SUNDAY MORNING AND AFTERNOON. A BACKDOOR FRONT
WILL MOVE INTO THE NORTH CAROLINA WATERS LATE SUNDAY AFTERNOON AND
CONTINUE SOUTH TO SOUTH SANTEE BY EARLY MONDAY. THE FRONT WILL
DISSIPATE AND WINDS WILL VEER TO SOUTH/SOUTHEAST BY MONDAY
EVENING. THE STRONGEST WINDS OCCUR EARLY MONDAY AROUND 15 KNOTS
BUT ANY BRIEF SURGE MAY INCREASE SPEEDS SLIGHTLY MORE. SEAS REMAIN
RELATIVELY BENIGN CITING THE WINDS. 2-3 FEET INITIALLY WILL
INCREASE FROM THE NORTH TO A RANGE OF 2-4 FEET.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 3:00 PM SATURDAY...WEST ATLANTIC HIGH PRESSURE THE DOMINANT
WIND MAKER THROUGH THE LONG TERM PERIOD. A SOUTHERLY COMPONENT
WILL THUS BE OMNIPRESENT ALTHOUGH SOME VARIATION BETWEEN
SOUTHEASTERLY AND SOUTHWESTERLY MAY OCCUR. CURRENTLY A SHIFT FROM
S OR SE TO SW EXPECTED TO OCCUR BETWEEN TUE AND WED AS RIDGE AXIS
OF THE PARENT HIGH SINKS SOUTH OF THE REGION. THIS WILL LIKELY BE
THE ONLY MINOR VARIATION THROUGH THE PERIOD. LITTLE REFLECTION IN
OVERALL WAVE HEIGHT EXPECTED AND A 2 TO 3 FT FORECAST WILL HOLD
FOR MOST OF THE VALID TIME.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...REK/TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...MRR
MARINE...REK/TRA/MBB/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
804 PM EDT SAT APR 28 2012
.SYNOPSIS...
A COLD FRONT WILL MEANDER ABOUT THE REGION THROUGH EARLY MONDAY. A
SUMMERTIME PATTERN WILL THEN DEVELOP AND CONTINUE THROUGH THE
REMAINDER OF THE PERIOD.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 8:00 PM SATURDAY...SHOWERS DEVELOPED LATE THIS AFTERNOON AT
THE INTERSECTION OF THE SEA BREEZE FRONT AND THE STALLED FRONT
OVER SOUTHERN MARION COUNTY AND WEST-CENTRAL HORRY COUNTY. THESE
SHOWERS FADED WITH THE SETTING SUN AND BASED ON LATEST GUIDANCE
EXPECT A QUIET NIGHT AHEAD. MINOR TWEAKS TO THE GRIDDED DATABASE
TO ADJUST THE TEMPERATURE CURVE IN SOME LOCATIONS. FORECAST
REMAINS ON TRACK. PREVIOUS DISCUSSION FOLLOWS:
CLOUDS ALONG AND NORTH OF THE STALLED FRONT HAVE BEEN EXCEEDINGLY
RESILIENT TO BURNING OFF DESPITE RELATIVELY STEEP LATE-APRIL SUN
ANGLES AND THE LACK OF PRECIPITATION. WITH THE SUN ALREADY PASSING
INTO THE WESTERN SKY WE HAVE TO ENTERTAIN THE NOTION THAT CLOUDS
WILL PERSIST SOLIDLY THROUGH SUNSET IN THE LUMBERTON AND
BENNETTSVILLE AREAS WITH HIGHS PERHAPS REACHING THE LOWER 70S
BEFORE FALLING AGAIN THIS EVENING. THE FRONT HAS BECOME
CONCOMITANT WITH THE SEABREEZE AT THE COAST AND APPEARS TO LIE
ALONG A LINE FROM SOUTHPORT TO GREEN SEA TO MARION AND FLORENCE.
THE BOUNDARY WILL SLOWLY MOVE NORTH TONIGHT...FINALLY LIFTING
THROUGH LUMBERTON AROUND MIDNIGHT. EAST TO NORTHEAST WINDS ON THE
COOL SIDE OF THE BOUNDARY WILL TURN SOUTHERLY. THERE SHOULD NOT BE
AN INCREASE IN WIND SPEEDS DOWN HERE AT THE SURFACE BEHIND THE
FRONT DUE TO ONLY A WEAK LOW LEVEL JET ALOFT...15-20 KT IN THE
1000-2000 FT LAYER. THIS WILL HOPEFULLY BE JUST ENOUGH WIND TO
PREVENT WIDESPREAD FOG DEVELOPMENT BUT WILL INSTEAD FAVOR THE
FORMATION OF LOW STRATUS CLOUDS AFTER MIDNIGHT.
ALTHOUGH SPC AND RUC MESO ANALYSIS SHOW SURFACE-BASED CAPE ON THE
ORDER OF 1000-1500 J/KG ACROSS INLAND SOUTH CAROLINA...DRY
ENVIRONMENTAL CONDITIONS BETWEEN THE LCL AND LFC AND THE NOTABLE
LACK OF ANY UPPER AIR IMPULSES MEAN THERE IS ONLY A TINY CHANCE
FOR A SHOWER OR THUNDERSTORM TO FORM BETWEEN NOW AND SUNSET. IF
ANYTHING WERE TO FORM IT WOULD LIKELY BE NEAR THE INTERSECTION OF
THE SEABREEZE AND THE SYNOPTIC FRONT...SOMEWHERE FROM MARION AND
TABOR CITY TO LAKE WACCAMAW. LOWS TONIGHT SHOULD FALL INTO THE
LOWER TO MID 60S...7-10 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3:00 PM SATURDAY...THE PERSISTENT BAROCLINIC ZONE WILL
CONTINUE TO BE AN ISSUE THROUGH THE PERIOD AS IT MAKES ANOTHER RUN
TO THE SOUTH LATER SUNDAY AS THE MID LEVEL RIDGE AMPLIFIES ACROSS
THE MIDWEST. FORECAST CHALLENGE WILL PRIMARILY BE POPS.
FOR SUNDAY...MIXED LAYER CAPE VALUES INCREASE TO APPROXIMATELY
2000K J/KG PER THE GFS ACROSS NORTHERN ZONES AS THE FRONT SLIPS
SOUTH. THIS INSTABILITY ALONG WITH THE FORCING WITH A SUBTLE
SHORTWAVE THROWN IN FOR GOOD MEASURE WARRANTS LOWER CHANCE POPS
FOR THESE AREAS LATE SUNDAY INTO THE EVENING HOURS.
POPS DIMINISH WITH THE LOSS OF DAYTIME HEATING SUNDAY NIGHT INTO
EARLY MONDAY BUT THE OVERCAST SKIES...MOISTURE TRAPPED UNDER A
CONSIDERABLE SUBSIDENCE INVERSION WILL CONTINUE TO INCREASE
SOUTHWARD.
MONDAY IS A TRANSITION DAY AS THE FRONT DISSIPATES AS THE
SOUTHERLY FLOW DEVELOPS. HOWEVER THIS WILL TAKE SOME TIME AND THE
INVERSION REMAINS PRESENT MOST OF THE DAY AND ALTHOUGH THE GFS AND
NAM ARE DEVELOPING A LITTLE LIGHT QPF...INDICATIONS ARE THIS IS
THE AFOREMENTIONED MOISTURE/STRATUS DECK.
TEMPERATURE GUIDANCE HAS WARMED SLIGHTLY AND THE MAIN CHALLENGE
APPEARS TO BE MONDAY MORNING LOWS AS THE CLOUD COVER WILL BE
INCREASING AND IT APPEARS THE BEST STRATEGY WILL BE TO ADD A
DEGREE OR TWO TO THE NUMBERS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3:00 PM SATURDAY...CONDITIONS WILL REMAIN LARGELY RAIN-FREE
THROUGH THE LONG TERM AS AN UPPER LEVEL RIDGE AXIS BUILDS ACROSS
THE EAST COAST. SURFACE HIGH PRESSURE WILL SIMILARLY SHOW LITTLE
MOVEMENT ACROSS THE WEST ATLANTIC. THIS LATTER FEATURE WILL IMPORT
WARM AND MOIST AIR ACROSS THE SOUTHEASTERN U.S. LEADING TO
SLIGHTLY WARM TEMPERATURES BY DAY AND EVEN MORESO WARMTH DURING
THE NIGHTTIME HOURS AS MOISTURE ACTS AS A LIMITING FACTOR FOR
COOLING. THIS LOW LEVEL MOISTURE PAIRED WITH THE WARM WILL AT SOME
POINT TRY TO START FIRING DIURNAL CONVECTION ALONG THE SEA BREEZE.
THE SUBSIDENCE ASSOCIATED WITH THE RIDGING ALOFT WILL KEEP THIS
ACTIVITY ISOLATED ENOUGH TO PRECLUDE BEING PUT IN THE FORECAST AT
THIS TIME HOWEVER.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...TERMINALS ARE CURRENTLY VFR...EXCEPT AT FLO WHERE
CEILINGS WERE MVFR. A STATIONARY FRONT WAS LOCATED JUST TO THE SOUTH
OF THE TERMINALS. AN UPPER IMPULSE WILL APPROACH OVERNIGHT...BUT
SHOULD PASS WELL TO THE NORTH. AS IT APPROACHES THE FRONT WILL BEGIN
TO MOVE SLOWLY NORTH THROUGH THE TERMINALS. AS THE UPPER IMPULSE
PASSES THE FRONT SHOULD MOVE BACK TO THE SOUTH AT LEAST THROUGH THE
ILM/LBT TERMINALS BY AFTERNOON.
THE MAIN FORECAST CONCERN WILL BE MVFR/IFR STRATUS/FOG POTENTIAL
THIS EVENING AND OVERNIGHT. FEEL THE BEST FOG POTENTIAL WILL BE AT
THE FLO/LBT TERMINALS. IFR WILL BECOME LIKELY BY 06Z. AFTER MIDNIGHT
INCREASING MID-LEVEL CLOUD COVER AND INCREASING BOUNDARY LAYER WINDS
SUGGEST VISIBILITIES MAY IMPROVE BUT AN IFR STRATUS LAYER WILL
BECOME MORE LIKELY. AT THE COASTAL TERMINALS MVFR CEILINGS WILL BE
LIKELY THIS EVENING...WITH THE BEST IFR POTENTIAL AFTER MIDNIGHT.
VFR EXPECTED AFTER 13-15Z AT ALL TERMINALS. WINDS WILL BECOME LIGHT
SOUTHWEST OVERNIGHT...THEN BECOME WEST TO WEST-NORTHWEST AFTER
SUNRISE. BY AFTERNOON WINDS WILL BECOME SOUTH...EXCEPT NORTHEAST TO
EAST NORTHEAST LBT AND EAST TO EAST-SOUTHEAST AT ILM. ISOLATED SHOWERS
ARE POSSIBLE FROM LBT TO ILM ALONG THE FRONT DURING THE AFTERNOON.
EXTENDED OUTLOOK...A SLIGHT CHANCE OF MVFR/SHOWERS THROUGH TUESDAY.
LOW CONFIDENCE IFR VSBYS IN MORNING FOG TUESDAY AND WEDNESDAY.
MODERATE CONFIDENCE SCATTERED THUNDERSTORMS THURSDAY NORTHERN
TERMINALS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 8:00 PM SATURDAY...STALLED FRONT NOW BISECTING THE WATERS IN
THE CAPE FEAR VICINITY...WITH LIGHT AND VARIABLE WINDS OVER MOST
OF OUR WATERS AT THIS TIME. SEA BREEZE FROM THIS AFTERNOON HAS
FADED ALTHOUGH WINDS ARE STILL ONSHORE WITHIN A FEW MILES OF THE
COAST. HAVE ADDED VARIABLE WIND VERBIAGE TO THE FORECAST FOR EARLY
ON THIS EVENING...OTHERWISE FORECAST REMAINS UNCHANGED FROM
PREVIOUS DISCUSSION BELOW:
THE FRONT HAS MOVED VERY LITTLE DURING THE DAYLIGHT HOURS...STILL
STALLED FROM THE CAPE FEAR VICINITY INLAND ACROSS EXTREME NORTHERN
SOUTH CAROLINA. THE AFTERNOON SEABREEZE HAS MADE PRECISE FRONTAL
ANALYSIS DIFFICULT WHERE SOUTHEAST WINDS HAVE DEVELOPED NEAR THE
COAST. MODELS ARE ALMOST UNANIMOUS WITH THEIR DEPICTIONS OF THE
FRONT MOVING SLOWLY NORTH TONIGHT...FINALLY REACHING TOPSAIL
ISLAND A FEW HOURS AFTER SUNSET. SOUTH WINDS WILL OVERSPREAD THE
AREA WITH SPEEDS INCREASING TO 10-15 KT. IT APPEARS DRY WEATHER
WILL CONTINUE THROUGH THE NIGHT.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3:00 PM SATURDAY...INITIALLY WINDS WILL CONTINUE FROM THE
SOUTHWEST ACROSS ALL WATERS AND WITH THE RESULTANT SEA BREEZE
BACKING WINDS LATE SUNDAY MORNING AND AFTERNOON. A BACKDOOR FRONT
WILL MOVE INTO THE NORTH CAROLINA WATERS LATE SUNDAY AFTERNOON AND
CONTINUE SOUTH TO SOUTH SANTEE BY EARLY MONDAY. THE FRONT WILL
DISSIPATE AND WINDS WILL VEER TO SOUTH/SOUTHEAST BY MONDAY
EVENING. THE STRONGEST WINDS OCCUR EARLY MONDAY AROUND 15 KNOTS
BUT ANY BRIEF SURGE MAY INCREASE SPEEDS SLIGHTLY MORE. SEAS REMAIN
RELATIVELY BENIGN CITING THE WINDS. 2-3 FEET INITIALLY WILL
INCREASE FROM THE NORTH TO A RANGE OF 2-4 FEET.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 3:00 PM SATURDAY...WEST ATLANTIC HIGH PRESSURE THE DOMINANT
WIND MAKER THROUGH THE LONG TERM PERIOD. A SOUTHERLY COMPONENT
WILL THUS BE OMNIPRESENT ALTHOUGH SOME VARIATION BETWEEN
SOUTHEASTERLY AND SOUTHWESTERLY MAY OCCUR. CURRENTLY A SHIFT FROM
S OR SE TO SW EXPECTED TO OCCUR BETWEEN TUE AND WED AS RIDGE AXIS
OF THE PARENT HIGH SINKS SOUTH OF THE REGION. THIS WILL LIKELY BE
THE ONLY MINOR VARIATION THROUGH THE PERIOD. LITTLE REFLECTION IN
OVERALL WAVE HEIGHT EXPECTED AND A 2 TO 3 FT FORECAST WILL HOLD
FOR MOST OF THE VALID TIME.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...REK/TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...SGL
MARINE...REK/TRA/MBB/SHK
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 PM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL BECOME NEARLY STATIONARY OVER SOUTH CAROLINA THIS
AFTERNOON AND EVENING. THE FRONT IS THEN EXPECTED TO PUSH BACK
NORTHWARD AS A WARM FRONT SATURDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 300 PM FRIDAY...
THE COLD FRONT HAS SETTLED TO NEAR THE NC/SC BORDER AS OF
MID-AFTERNOON. HIGH PRESSURE (1025+ MB) CONTINUED TO BUILD INTO
CENTRAL AND EASTERN NC FROM THE GREAT LAKES. THE POSITION OF THE
COLD FRONT WAS DEPICTED NICELY ON THE LATEST VISIBLE SATELLITE DATA
BY A CUMULUS FIELD. THIS CONVERGENCE ZONE WHERE CUMULUS WERE
DEVELOPING EXTENDED IN A WEST TO EAST FASHION FROM NEAR CHARLOTTE TO
FAYETTEVILLE TO NEW BERN. THE TEMPERATURES ALONG AND AHEAD OF THE
FRONT WERE GENERALLY IN THE LOWER 80S WITH DEW POINTS AROUND 60. IT
IS IN THIS REGION WHERE THE LATEST HI-RES MODELS WITH SUPPORT FROM
SEVERAL OPERATIONAL MODEL SOLUTIONS INDICATE THAT THERE WILL BE A
GOOD CHANCE OF SHOWERS AND POSSIBLY THUNDERSTORMS LATER THIS
AFTERNOON INTO THE EVENING HOURS.
STRONG HEATING WITH NEARLY FULL SUN (INTO THE LOWER 80S)...
AMPLE LOW LEVEL MOISTURE (DEW POINTS AROUND 60)... ALONG WITH THE
PRESENCE OF A WEAK MESO-LOW (CONVERGENCE)... AND UPPER SUPPORT
(COOLING ALOFT AND ASSOCIATED LIFT)... TRACKING ESE ALONG A BOUNDARY
(FOCUS)... ALL SUPPORT CONTINUED CONVECTIVE DEVELOPMENT. THE SEVERE
THREAT IS EXPECTED TO BE SOUTH OF THE CURRENT POSITION OF THE FRONT
WHICH WOULD PLACE ALMOST ALL OF NC OUTSIDE THE SEVERE RISK AREA. THE
LATEST HRRR SEEMS TO BE PICKING UP WELL ON THE CURRENT DEVELOPING
SCATTERED CONVECTION FROM NE GA INTO UPSTATE SC (ALONG A WEAK LOW
PRESSURE ASSOCIATED WITH THE FRONT). THIS MODEL SUGGESTS THAT
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP EASTWARD OR
EAST-SOUTHEASTWARD ALONG THE BOUNDARY AIDED BY THE APPROACH OF A
WEAK WAVE ALOFT ACROSS ANSON... RICHMOND... HOKE... AND SCOTLAND
COUNTIES BY LATE AFTERNOON. THIS ACTIVITY SHOULD TRACK ESE AND
POSSIBLY AFFECT CUMBERLAND AND PORTIONS OF SAMPSON COUNTY BEFORE
SHIFTING WELL SOUTHEAST INTO SC AND OFFSHORE BY AROUND MID-EVENING.
THE STRONGER STORMS ARE EXPECTED TO BE CONFINED TO AREAS SOUTH OF
THE NC/SC BORDER.
TO THE NORTH... CONTINUED CAA/DAA SUPPORT CONTINUED STABILIZING OF
THE BOUNDARY LAYER WITH NIL POP EXPECTED. LATER TONIGHT... ALL AREAS
SHOULD BE PARTLY CLOUDY... BECOMING CLOUDY TOWARD DAYBREAK (SOUTH).
LOWS IN THE 45-50 RANGE EXPECTED NORTH... RANGING INTO THE MID 50S
SOUTH. THERE MAY BE SOME LIGHT RAIN AGAIN LATE ESPECIALLY SOUTH. WE
WILL INCLUDE LOW CHANCE POP AGAIN LATE FOR THAT POTENTIAL.
FOR SATURDAY... MODELS GENERALLY AGREE IN THAT THE FRONT OVER SC
WILL LIFT BACK NORTHWARD AS A WARM FRONT DURING THE LATE AFTERNOON
AND EVENING. LOW LEVEL MOISTURE WILL AGAIN BE ON THE INCREASE AS THE
DAY PROGRESSES AS A WARM AIR ADVECTION WIND PROFILE FLOW STRENGTHENS
FROM SW TO NE ACROSS THE REGION. MODELS GENERALLY DO NOT GENERATE
MUCH IN THE WAY OF RAINFALL SATURDAY WHICH SHOULD ALLOW THE WARM
FRONT FOR MORE OF AN EASIER/QUICKER TRACK OVER THE AREA. HOWEVER...
THE NAM MOS GUIDANCE (COOLER) APPEARS MORE REASONABLE GIVEN THE
EXPECTED INCREASE IN MOISTURE BETWEEN THE SURFACE AND 6-10K FEET AGL
ASSOCIATED WITH THE WAA. IT IS NOT UNTIL SATURDAY EVENING OR
OVERNIGHT IN WHICH THE SIGNIFICANT DRYING UP OF LOW TO MID LEVELS
SUPPORTS CLEARING. THIS OCCURS AS THE WARM FRONT LIFTS NORTH AND THE
LOW AND MID LEVEL FLOW BECOMES WESTERLY. EXPECT CLOUDY SKIES
SATURDAY WITH A LOW END POP FOR SOME LIGHT RAIN. QPF WILL BE LIGHT
(LESS THAN 0.10). HIGHS SHOULD END UP FROM THE MID 60S N-NE RANGING
INTO THE MID 70S FROM FAY TO LAURINBURG. -BADGETT
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM FRIDAY...
SATURDAY NIGHT AND SUNDAY... THE WSW FLOW IN THE LOW AND MID LEVELS
WILL CONTINUE TO BRING DRYING AND WARMING. MODELS DISAGREE ON TIMING
OF ANOTHER COLD FRONT SUNDAY. IT APPEARS LIKELY THAT THERE WILL BE
LARGE SPREAD IN TEMPERATURES FROM SOUTHERN VA INTO NC SUNDAY
AFTERNOON. IT IS STILL TOO EARLY TO PIN THAT DOWN AT THE PRESENT
TIME. FOR NOW... EXPECT SUNDAY TO BRING SOME EARLY LINGERING CLOUDS
AND POSSIBLY FOG (ESPECIALLY N-E). THE SKIES SHOULD BECOME MOSTLY
SUNNY. AFTER MILDER LOWS IN THE MID 50S TO MID 60S N TO S... HIGHS
WILL SURGE WELL INTO THE 80S... LOWER TO MID 80S (NORTH) AND UPPER
80S SOUTH. THESE READINGS MAY FALL BACK INTO THE 70S (OR EVEN REMAIN
THERE IN THE NE ZONES) DEPENDING ON THE TIMING OF THE FRONT SUNDAY
AFTERNOON. REGARDLESS... THE WARMTH SUNDAY WILL BE SHORT LIVED AS
YET ANOTHER COLD FRONT WILL DIVE SE THROUGH THE REGION LATE SUNDAY
INTO SUNDAY NIGHT. THIS WILL BE DRIVEN SOUTHWARD BY A 1028+ MB HIGH
OVER THE GREAT LAKES BY 00Z/MON. THERE IS A CHANCE OF A FEW
THUNDERSTORMS SUNDAY AFTERNOON AND EVENING AS THE FRONT COMES INTO
THE REGION. -BADGETT
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 300 PM FRIDAY...
SUNDAY NIGHT AND MONDAY...THE MID LEVEL RIDGE OVER THE MISS RIVER
VALLEY WILL MOVE TO THE EASTERN SEABOARD...MEANWHILE HIGH PRESSURE
OVER THE GREAT LAKES AND NEW ENGLAND REGION WILL SHIFT ESE BECOMING
CENTERED OVER THE WESTERN ATLANTIC BY LATE MONDAY. THE COLD FRONT
WHICH WILL HAVE MOVED SOUTH ACROSS OUR CWA DURING THE DAYTIME SUNDAY
WILL SLOW DOWN OR BE STALLED JUST TO OUR SOUTH. IN THE PROCESS...LOW
LEVEL FLOW WILL BECOME NE BEHIND THE FRONT SUNDAY NIGHT...BUT THEN
SHIFT TO E MONDAY MORNING AND SE BY LATE MONDAY AS THE HIGH MOVES
ESE. FORECAST SOUNDINGS FOR 00Z-12Z MONDAY SHOW THAT WITH COOL LOW
LEVELS...LINGERING MOISTURE BETWEEN H7-H9...AND WEST FLOW ALOFT...
EXPECT STRATUS TO FORM OVERNIGHT AND LINGER INTO MONDAY MORNING.
LOWS WILL RANGE FROM AROUND 50 NORTH FARTHER BEHIND THE FRONT...TO
UPPER 50S SOUTH CLOSER TO THE FRONT. DURING THE DAYTIME MONDAY...THE
LOW LEVEL CLOUDS MAY BE TOUGH TO BREAK AS THE MID LEVELS CONTINUE TO
WARM AND STRENGTHENS THE INVERSION. DESPITE A MODEST LAYER OF LOW
LEVEL MOISTURE AND RESULTING CLOUDINESS...LIFTING MECHANISMS WILL BE
LIMITED THUS WILL KEEP POPS AOB 15 PERCENT MONDAY. CLOUDINESS WILL
HELP KEEP TEMP BELOW NORMAL...WITH HIGHS RANGING FROM THE MID 60S
NORTH TO LOWER 70S SOUTH.
FOR MONDAY NIGHT...LIGHT SE LOW LEVEL FLOW WILL CONTINUE...THUS
ADDITIONAL LOW STRATUS AND PERHAPS SOME FOG IS EXPECTED INTO TUESDAY
MORNING. WITH LOW CLOUDS AND SOUTHERLY COMPONENT TO THE LOW LEVEL
FLOW...TEMPS WILL REMAIN ABOVE NORMAL WITH LOWS GENERALLY IN THE
MID-UPR 50S.
THEN FOR THE MIDDLE OF THE WEEK (TUES-THURS)...EXPECT GENERALLY FAIR
WEATHER WITH LIMITED LIFTING MECHANISMS AS A BROAD RIDGE REMAINS
PARKED OVER THE SOUTHEAST AND THE BEST DYNAMICAL FORCING REMAIN TO
OUR NORTH. ALTHOUGH PWAT DURING THIS TIME WILL BE NEAR
CLIMATOLOGICAL NORMS...FORECAST SOUNDINGS ARE RELATIVELY DRY BETWEEN
550-850MB. FOR NOW WILL CONTINUE WITH POPS AOB 15 PERCENT.
PERSISTENT AND DEEP SW FLOW AND RESULTING THICKNESS VALUES SUGGEST
TEMPS SOME 5-10 DEGREE ABOVE NORMAL EACH DAY DURING THIS TIME...
HIGHS GENERALLY IN THE LOW 80S AND LOWS IN THE UPPER 50S.
FINALLY BY THURSDAY NIGHT AND FRIDAY...THE AFOREMENTIONED RIDGE WILL
FLATTEN AS A POTENT SHORTWAVE MOVES EASTWARD FROM THE ROCKIES.
ALTHOUGH THE LEE TROUGH SHARPENS ON FRIDAY AS WNW FLOW INCREASES...
MOISTURE IS PROGGED TO REMAIN LIMITED...SO RIGHT NOW MOST OF FRIDAY
LOOKS DRY...WITH BETTER RAIN CHANCES HOLDING OFF UNTIL LATE IN THE
DAY AS THE SHORT WAVE DIGS ACROSS THE REGION.
&&
.AVIATION /18Z FRIDAY THROUGH MONDAY/...
AS OF 300 PM FRIDAY...
VFR CONDITIONS EXPECTED THIS AFTERNOON AND EVENING AT ALL TAF SITES.
MVFR CIGS SHOULD DEVELOP NORTHWARD INTO THE KFAY AREA BY 12Z... THEN
REACH THE KRDU/KGSO TAF SITES. MVFR CIGS EXPECTED SATURDAY... BEFORE
LIFTING TO VFR SATURDAY NIGHT. VFR CONDITIONS EXPECTED SUNDAY...
BECOMING MVFR CIGS AGAIN LATE SUNDAY AND SUNDAY NIGHT.
OUTLOOK...GENERALLY MVFR CIGS SHOULD LIFT TO VFR BEFORE MONDAY...
VFR CONDITIONS EXPECTED MONDAY AND TUESDAY. PATCHY EARLY MORNING LOW
STRATUS/FOG MAY OCCUR MONDAY AND TUESDAY MORNINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...PETRO
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
735 AM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA EARLY THIS MORNING...THEN
JUST SOUTH OF THE REGION THIS AFTERNOON AND EVENING. THE FRONT WILL
DRIFT BACK N OVER THE AREA LATE SATURDAY...THEN SOUTH OF THE AREA
GAIN SUNDAY NIGHT. HIGH PRESSURE WILL BUILD ACROSS NORTH OF THE AREA
MONDAY...THEN DRIFT OFFSHORE TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 700 AM FRIDAY...NO SIGNIFICANT CHANGES WITH UPDATE. ALL
CONVECTIVE ACTIVITY HAS MOVED OFFSHORE WITH SHRT WV AND FRONT HAS
REACHED NRN OBX...ON TRACK TO MOVE ACROSS AREA DURING MORNING. SCU
HAS DEVELOPED OVER NRN 2/3 OF AREA AND EXPECTED TO SPREAD S WITH
FRONTAL PROGRESSION...THEN DIMINISH FROM N TO S DURING AFTN AS DRY
AIR MOVES IN. LATEST NAM12 AND HRRR DO INDICATE PCPN PSBL OVER SRN
ONSLOW COUNTY LATE AFTN WITH FRONT AND SEA BREEZE INTERACTION...WILL
LET DAY SHIFT TAKE A LOOK FOR PSBL ADDING POPS WITH LATER UPDATE.
/PREVIOUS DISCUSSION.
AS OF 300 AM FRIDAY...CURRENT CONVECTIVE ACTIVITY ALONG SRN OBX WILL
MOVE OFFSHORE NEXT HOUR OR SO BUT WILL CONTINUE TO CARRY SLGT CHC
POPS ALONG COAST EARLY THIS MORNING UNTIL FRONTAL PASSAGE AND SHRT
WV MOVES OFFSHORE. MODELS IN DECENT AGREEMENT OF FRONT BACKDOORING
THROUGH AREA 6AM-10AM...BRINGING SLIGHTLY COOLER AND DRIER AIR MASS
TO AREA...WITH MOST NOTICEABLE CHANGE IN TEMPS OVER NRN OBX. WEAK
SUBSIDENCE AND MORE STABLE CONDITIONS WILL KEEP PCPN THREAT S OF
AREA DURING THE DAY. MINOR ADJUSTMENTS TO MAX TEMPS WITH LATEST MOS
BLEND. HIGHS MAINLY LOW-MID 70S EXCEPT LOW-MID 60S OBX.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
AS OF 300 AM FRIDAY...HIGH PRES EXTENDING OVER AREA WILL PRODUCE
FAIR WX CONDITIONS THIS EVENING...THEN NEXT SHRT WV APPROACHING FROM
W WILL INDUCE LOW PRES WAVE ALONG FRONT TO S OF AREA
OVERNIGHT...WITH THREAT OF SHOWERS SPREADING OVER ALL BUT EXTREME NE
SECTIONS BY MORNING. BASED ON MODEL AGREEMENT...INCREASED POPS TO
50% OVER SRN SECTIONS...TAPERING TO 30% N-NE. MINOR ADJUSTMENTS TO
MIN TEMPS...MAINLY LOWERED SLIGHTLY AS RADIATIONAL COOLING
CONDITIONS MAY ALLOW TEMPS TO DROP QUICKLY THIS EVENING.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 330 AM FRI...RATHER TRICKY LONG TERM FCST AS A FRONT WAVERS
BACK AND FORTH ACROSS THE REGION THIS WEEKEND THROUGH EARLY NEXT
WEEK. FOR SAT...UNSETTLED WEATHER IS EXPECTED AS E NC IS UNDER CAA
TYPE REGIME WITH HIGH PRES TO THE NORTHEAST RIDGING INTO THE AREA
WITH EASTERLY SFC FLOW. AT THE SAME TIME...H85 WARM FRONT WILL LIFT
NORTH THROUGH E NC AS SWRLY FLOW ALOFT INC. THIS WILL BRING INC IN
ISENTROPIC LIFT...AND WITH FRONTAL INVERSION DEVELOPING...A RATHER
COOL DAY WILL BE ON TAP WITH WIDESPREAD LOW CLOUDS AND SCT PRECIP.
THERE IS A CHANCE FOR SOME THUNDER FOR SOUTHERN PORTIONS OF THE FA
AS ELEVATED CAPE WORKS ITS WAY INTO THE REGION FROM THE SW. WITH
DEEP LAYER SHEAR PRESENT...A FEW THUNDERSTORMS MAY BE PRESENT IN THE
SCT SHOWER ACTIVITY.
SFC HIGH WILL WEAKEN/MOVE FURTHER OFFSHORE SAT NIGHT...ALLOWING FOR
RETURN SFC FLOW TO DEVELOP AND SCOUR OUT LOW CLOUDS/PRECIP. THE SFC
WARM FRONT WILL BE SITUATED ACROSS THE VA/NC BORDER SUN MORNING...
BEFORE DROPPING SOUTH AS A COLD FRONT DURING THE DAY. LARGE TEMP
GRADIENT POSSIBLE SUNDAY...WITH TEMPS IN THE WARM SECTOR ACROSS SW
ZONES REACHING WELL INTO THE 80S...WITH NEAR 70 READINGS ACROSS THE
NORTHERN OBX. TEMPS WILL BE NEAR AVG FOR OVERNIGHT LOWS SUN NIGHT
THROUGH MON NIGHT WITH CLOUDINESS EXPECTED...WITH HIGHS A BIT BELOW
NORMAL DUE TO THE NE FLOW AND MOSTLY CLOUDY SKIES. BUILDING HEIGHTS
EXPECTED FOR TUE THROUGH MID WEEK...WITH TEMPS INCREASING INTO THE
80S EACH AFTERNOON.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /12Z FRIDAY THROUGH 12Z SATURDAY/...
AS OF 720 AM FRIDAY...VFR PREVAILING THROUGH THIS EVENING...THEN
SOME LOWER CLOUDINESS PSBL LATE TONIGHT. BACKDOOR FRONT WILL PUSH
THROUGH AREA FROM N THIS MORNING WITH MAIN EFFECT BEING WIND SHIFT
TO N. SHRT WV HAS MOVED OFFSHORE AND NO CONVECTIVE ACTIVITY EXPECTED
WITH FRONT. SCU CIGS 5-6K FT WILL SPREAD S THIS MORNING...THEN
DIMINISH THIS AFTN. NEXT SHRT WV WILL SPREAD CHC OF SHOWERS SW TO NE
OVERNIGHT...AND DEVELOPING EASTERLY FLOW MAY RESULT IN SOME MVFR
CIGS LATE...ESPECIALLY KOAJ AND KEWN...BUT LOW CONFIDENCE AT THIS
TIME.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM FRI...PERIOD OF MVFR OR POSSIBLY IFR FOR SAT AS FRONTAL
INVERSION DEVELOPS. SCT SHOWERS WILL BE POSSIBLE. CLOUDS SHOULD LIFT
AND SCATTER ON SAT NIGHT AS FRONT LIFTS NORTH OF THE REGION. THE
FRONT WILL SLOWLY DROP BACK SOUTH DURING THE DAY SUNDAY...WITH AN
INC IN CLOUDS AGAIN EXPECTED...ESPECIALLY INTO SUNDAY NIGHT AND
MONDAY. MAY AGAIN SEE CLOUDS LOWER TO MVFR CAT.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 720 AM FRIDAY...FRONT MOVING THROUGH NRN MOST WATERS AND ON
TRACK TO MOVE ACROSS AREA THIS MORNING...WITH POST-FRONTAL NRLY
SURGE. GUSTS UP TO 30 KT OBSERVED UPSTREAM...THUS NO CHANGE IN SCA
FOR SOUNDS THROUGH THIS MORNING...AND OVER COASTAL WATERS INTO THIS
AFTN DUE TO LINGERING 6 FT SEAS.
/PREVIOUS DISCUSSION/
AS OF 300 AM FRIDAY...MODELS CONTINUE TO APPEAR SLIGHTLY UNDERDONE
WITH POST-FRONTAL CAA SURGE THIS MORNING...AND EXPECT PERIOD OF
GUSTS TO 25 KT PER CURRENT OBS UPSTREAM...AND NO CHANGES TO SCA FOR
ALL OF WATERS. WINDS AND SEAS WILL GRADUALLY DIMINISH BELOW 15 KT
ALL WATERS THIS AFTN AND EVENING...THEN INCREASE SRN WATERS
OVERNIGHT WITH TIGHTENING PRES GRAD.
LEANED TO PREVIOUS FCST AND WW3 FOR SEAS.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM FRI...WINDS WILL BE EASTERLY SAT AS HIGH PRES RIDGES
INTO E NC FROM THE NE. RETURN FLOW WILL DEVELOP SAT EVENING AS FRONT
LIFTS NORTH OF THE AREA. THE SW FLOW WILL BE SHORT LIVED AS NE WINDS
DEVELOP ON SUNDAY WITH SFC COLD FRONT DROPPING SOUTH THROUGH THE
WATERS ONCE AGAIN. WINDS SHOULD REMAIN JUST BELOW SCA THROUGH THE
PERIOD WITH SEAS 2 TO 4 FEET. SOME 5 FOOT SETS POSSIBLE ACROSS THE
OUTER WATERS. FLOW BECOMES S TO SW TUE INTO WED AS A RIDGE OF HIGH
PRES BUILDS IN FROM THE WEST.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ130-
135.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR AMZ150-
152-154-156-158.
&&
$$
SYNOPSIS...CTC/JME
NEAR TERM...JBM/JME
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/JME/TL
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
852 PM CDT SAT APR 28 2012
.DISCUSSION...
FOR TONIGHT...RAIN BAND WHICH WAS FROM MINOT SOUTHEAST ACROSS THE
SOUTHERN FCST AREA TOWARD MINNEAPOLIS HAS BEEN PUSHING NORTH AND
WEAKENING THE LAST FEW HOURS. STILL SOME SPRNKLES-LIGHT RAIN IN A
FEW SPOTS GRAND FORKS TO CAVALIER IN THE NRN VALLEY. CLOUDS HAVE
RETURNED NORTHWARD TO INCLUDED ALL BUT FAR NORTHEAST FCST AREA.
IN ADDITION HAVE UPPER LOW IN WRN SD MOVING NORTH. DRY SLOT
WORKING NORTHEAST INTO THE ABERDEEN-HURON AREA SET OFF SOME
SHOWERS-TSTMS WHICH ARE JUST WEST OF ABERDEEN. THESE HAVE BEEN
WEAKENING IN THE PAST 30 MINUTES AS THEY MOVE NORTH AND WOULD
EXPECT THEM TO CONTINUE TO DO THE NEXT 1-2 HOURS. NET RESULT IS
TONIGHT WILL SEE LIMITED ACTIVITY WITH BEST POTENTIAL FOR ANY
SHOWERS IN AREAS WEST OF HALLOCK-GRAND FORKS-VALLEY CITY.
LOW CLOUD AREA FROM MINOT TO WAHPETON TO WEST OF THE TWIN CITIES
WILL LIKELY HOLD TONIGHT AND MAY GIVE A BIT OF DRIZZLE AT TIMES.
HRRR MODEL WANTS TO BRING IT NORTH A BIT INTO DVL REGION LATE
TONIGHT BUT KEEP AREAS NORTH OF FARGO OUT OF THE LOW STUFF.
TEMPS WERE RAISED A FEW DEGREES BASED ON CLOUDS AND DEW PTS.
&&
.AVIATION...ISSUE WILL BE CIGS. IFR CIGS ELBOW LAKE MN TO WAHPETON
TO JAMESTOWN WITH MVFR CIGS UP TO NR DVL-FARGO-WADENA. ISSUE IS
WILL THE LOW CIGS SPREAD NORTH OR NOT. HRRR KEEPS THEM IN SAME
AREA FOR MOST OF THE NIGHT AS SFC WINDS REMAIN MORE SOUTHEAST BUT
DOES MOVE THEN A BIT MORE NORTH LATE TONIGHT AS WINDS TURN MORE
SOUTHERLY. ATTM WENT THAT ROUTE WHICH KEPT IFR CIGS SOUTH OF DVL-
FAR TAF SITES. BUT THE POTENTIAL IS THERE FOR IFR CIGS TO REACH
FARGO-DEVILS LAKE OVERNIGHT INTO SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 316 PM CDT SAT APR 28 2012/
SHORT TERM...
PRECIP CHANCES WILL BE THE MAIN FORECAST HEADACHE FOR THE SHORT
TERM.
UPPER LOW CURRENTLY SEEN ON WV LOOP ROTATING SLOWLY NORTHWARD OUT
OF WESTERN SD. RADAR HAS A FAIRLY NARROW BAND OF RAIN FROM NEW
ROCKFORD TO ELBOW LAKE...WHICH FITS FAIRLY WELL WITH THE NAM
DEPICTION OF 700MB DEFORMATION. THE MODELS ARE ALL IN FAIRLY GOOD
AGREEMENT ON BRINGING THIS DEFORMATION BAND NORTH AND WEAKENING IT
SIGNIFICANTLY THIS EVENING. THE NORTHWARD PROGRESSION WILL ALSO
PUSH IT FURTHER INTO THE DRY AIR COMING IN FROM THE NORTHEAST.
THINK THAT THE BAND WILL FALL APART FAIRLY EARLY
TONIGHT...ALTHOUGH THERE WILL BE A FEW SCATTERED SHOWERS MOVING
INTO THE WESTERN CWA AS THE UPPER LOW CONTINUES TO MOVE CLOSER.
KEPT 30 TO 40 POPS BUT MAINLY IN THE NORTHWESTERN CWA.
THE UPPER TROUGH WILL MOVE INTO MANITOBA BY TOMORROW...TAKING THE
SFC LOW ALONG THE SASK/MANT BORDER. SOUTHERLY WINDS WILL BRING
SOME WARMER AIR INTO THE AREA...AND HIGHS SHOULD GET UP INTO THE
50S TO LOW 60S. MODELS DO NOT HAVE A LARGE AMOUNT OF SFC BASED
CAPE JUST A FEW HUNDRED J/KG...BUT WITH THE COLD AIR ASSOCIATED WITH
THE UPPER LOW THERE COULD BE SOME LOW TOPPED CONVECTION. THERE IS
A GOOD AMOUNT OF SHEAR...SO AGREE WITH PREVIOUS SHIFT THAT WILL
HAVE TO WATCH OUT FOR A SIMILAR SET UP TO THE 21 APRIL EVENT.
PRECIP WILL BEGIN TO MOVE INTO THE EASTERN CWA SUNDAY NIGHT AND
LINGER OVER THE LAKE OF THE WOODS AREA INTO MONDAY AS THE UPPER
LOW OPENS UP AND MOVES FURTHER NORTHEAST INTO ONTARIO. OTHER THAN
THE NORTHEASTERN CWA...MONDAY SHOULD BE FAIRLY QUIET AND MILD WITH
WEST WINDS HELPING HIGHS CLIMB INTO THE 60S.
THE NEXT SIGNIFICANT UPPER TROUGH WILL MOVE INTO MT MONDAY NIGHT
AND TUESDAY. MODELS ARE IN FAIRLY DECENT AGREEMENT ON SFC LOW
PRESSURE MOVING FROM WESTERN SD INTO THE EASTERN PLAINS BY LATE
TUESDAY. SOUTHERLY WINDS AHEAD OF THE LOW WILL CONTINUE TO BRING
WARM AND MOIST AIR INTO THE AREA. KEPT HIGHS IN THE UPPER 60S TO
LOW 70S...AND CONTINUED WITH A THUNDER MENTION AS THERE SHOULD BE
SOME DECENT CAPE VALUES INTO THE 1000-2000 J/KG RANGE.
LONG TERM... /TUE NIGHT THROUGH SAT/
MODELS ARE IN SIMILAR AGREEMENT EARLY IN THE PERIOD WITH AN
UNSETTLED PATTERN. FOR TUE NIGHT...UPPER TROUGH OVER NORTHEAST MT
RESULTING IN SW FLOW ALOFT AND A SFC LOW ALONG INTL BORDER...WITH
PRECIP ASSOCIATED WITH FROPA JUST EAST OF THE CWA. STILL HAVE HIGH
POPS IN OUR FAR EAST...BUT WILL LIKELY BE AT TAIL END OF ACTIVITY.
WHILE MODEL BLENDS STILL SHOWING SOME LOW POPS FOR WED...IT APPEARS
CWA WILL BE IN A DRY SLOT BEFORE WRAP AROUND PRECIP IMPACTS MAINLY
OUR NORTHERN ZONES FROM LATE WED NIGHT THROUGH THU MORNING. BEST
CHANCE FOR A DRY AND POSSIBLY SUNNY DAY IS FRIDAY...AS SFC RIDGE
EXTENDS SOUTHWARD OUT OF CANADA. ALTHOUGH MODELS CONTINUE TO SHOW
LOW POPS AT THE END OF NEXT WEEK...CONFIDENCE IS LOW AND BELIEVE IT
IS THE BEST DAY FOR DRY WEATHER.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/JR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
724 PM EDT SAT APR 28 2012
.SYNOPSIS...
FRONT REMAINS IN OUR VICINITY THROUGH TONIGHT...AND SLOWLY WEAKENING
SUNDAY. MOISTURE INCREASES AGAIN LATE MONDAY...BEFORE FRONT TRIES TO
LIFT TO OUR NORTH. MAJOR WARMUP BY MID WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
720 PM UPDATE...UPDATED POPS...LEANING ON THE HRRR AS IT SEEMS TO
HAVE A GOOD HANDLE ON CURRENT RADAR PICTURE WITH SHOWERS AND
THUNDERSTORMS ACROSS NORTHERN CWA...AND POSSIBLE CONVECTIVE COMPLEX
MOVING INTO SW CWA AS CURRENT STORMS IN IN/IL WEAKEN AND MOVE
SOUTHEAST.
PREVIOUS DISCUSSION...
VERY TRICKY FORECAST IN THE RAINFALL AND TEMPERATURE DEPARTMENTS.
GOING WITH FLASH FLOOD WATCH SOUTHWEST HALF OF AREA THOUGH
TONIGHT...EXCEPT FOR SOUTHWEST VIRGINIA.
MODELS ARE IN REASONABLE AGREEMENT WITH THE MASS FIELDS...HAVING
STALLED FRONT VICINITY THE OHIO RIVER SLOWLY SAG SOUTH AND EAST
ACROSS THE AREA LATE THIS AFTERNOON AND TONIGHT. FRONT THEN STALLS
OVER SOUTHWEST VIRGINIA BY MORNING...BEFORE WEAKENING DURING
SUNDAY. THERE IS A GENERAL ZONAL FLOW ALOFT...WITH A SERIES OF
UPPER DISTURBANCES RIDING ALONG THIS BOUNDARY THRU TONIGHT BEFORE
UPPER RIDGING TRIES TO BUILD ON SUNDAY. THUS...THIS WEATHER PATTERN
IS MUCH INFLUENCED BY MESOSCALE EVENTS.
RIGHT NOW...ONE UPPER DISTURBANCE AND ASSOCIATED CONVECTION CROSSING
SOUTHEAST OHIO AND NORTHWEST WEST VIRGINIA IS LAYING OUT BAND OF
SHOWERS EAST TO WEST. THIS MAY SET UP A TRAINING EVENT ACROSS
CENTRAL PORTIONS OF THE AREA LATE THIS AFTERNOON AND
EVENING...AFFECTING MAINLY THE NORTHWEST PORTION OF THE FLASH FLOOD
WATCH. WILL MAINTAIN HIGH POPS ACROSS CENTRAL AREAS THROUGH EARLY
TONIGHT...EVEN BEHIND THE DISTURBANCE...AS THERE IS A GOOD
BAROCLINIC ZONE WITH THE SLOWLY SAGGING FRONT.
THE NEXT VIGOROUS LOOKING UPPER DISTURBANCE TO RIDE ALONG THE
FRONT...CURRENTLY OUT IN ILLINOIS...WILL TACK EASTWARD OVERNIGHT.
THIS WILL ALLOW THE HEAVY RAIN THREAT TO SHIFT SOUTH INTO SOUTHERN
WEST VIRGINIA.
BY 12Z SUNDAY...THE FRONT WILL STALL ACROSS SOUTHWEST
VIRGINIA...BEFORE WEAKENING DURING SUNDAY AS UPPER RIDGING BUILDS A
BIT. ON SUNDAY...SHOWERS WILL BE MORE SCATTERED AND MAINLY ACROSS
THE SOUTH.
WITH THE FRONT STALLING...IT WILL BE DIFFICULT TO BRING COLD
ADVECTION SOUTHWARD. TEMPERATURES TONIGHT AND SUNDAY WILL DEPEND ON
CLOUDS AND SHOWERS. IN ANY EVENT...LOOKS LIKE GUIDANCE IS TOO HIGH
SUNDAY.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
UNSETTLED WX CONT THRU THE SHORT TERM AS UPR LVL RIDGING TRIES TO
EXPAND N FROM SE STATES. PESKY FRONTAL BOUNDARY AT THE SFC...SHALLOW
ALOFT...WILL SERVE AS THE FOCUS FOR SHRA/TSRA COMBINED WITH VARIOUS
UPR DISTURBANCES. LOOKS AS IF SUNDAY NIGHT INTO MONDAY WILL BE THE
DRIEST PERIODS IN THE SHORT TERM...HOWEVER EVEN WARM FRONT MAY HAVE
ENOUGH JUICE FOR A FEW AFTN SHRA/TSRA ACROSS SE OH/N WV. COLD FRONT
APPROACHES MONDAY NIGHT BEFORE LAYING OUT OVER THE AREA AS IT
BECOMES MORE PARALLEL TO THE FLOW. WILL KEEP HIGH CHC POPS FOR THIS
FOR NOW GIVEN UNCERTAINTY ON EXACT BOUNDARY POSITION AND TIMING OF
VARIOUS DISTURBANCES. AN ABUNDANCE OF CLDS AND POTENTIAL SHRA/TSRA
WILL TEND TO STAVE OFF IMPRESSIVE WAA IN LLVLS AS FAR AS TEMPS ARE
CONCERNED. HENCE STAYED AWAY FROM VERY WARM MAV GUIDANCE...INSTEAD
OPTING CLOSER TO ECMWF/MET NUMBERS. STILL...CRACKING 80 LOOKS GOOD
MONDAY AND TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE OSCILLATING FRONT FINALLY SHOULD LIFT TO OUR NORTH. ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS FROM MONDAY NIGHT AND TUESDAY
SHOULD BE DISSIPATING OR EXITING TUESDAY NIGHT...SO LOWERING POPS.
WITH THE BUILDING HEIGHTS OVER THE SOUTHEASTERN UNITED STATES...THE
FRONT SHOULD FINALLY PUSH FARTHER TO OUR NORTH...WEDNESDAY AND
THURSDAY...SO TEMPERATURES BECOMING ABOVE NORMAL. LOWER POPS
WEDNESDAY INTO THURSDAY ALSO...BUT AS OF NOW...LEFT SOME CHANCE POPS
WEDNESDAY AND LATE IN THE DAY THURSDAY IN THE NW. LEAST COVERAGE
SHOULD BE WEDNESDAY NIGHT INTO THURSDAY MORNING.
THE WARMER TEMPERATURES AND LOWER POPS WEDNESDAY INTO THURSDAY
SHOULD HELP TO DRY OUT THE TOP SOIL.
NEXT FRONTAL SYSTEM TIMED FOR FRIDAY...WITH COOLER AIR IN ITS WAKE.
NO MAJOR CHANGES TO HPC POPS AND TEMPERATURES.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
OUTSIDE OF SHOWERS ACTIVITY...EXPECTING VFR CONDITIONS THROUGH THE
EVENING. STALLED/SLOWLY SAGGING COLD FRONT CONTINUES TO REMAIN
ACROSS CWA...WITH SHOWERS AND THUNDERSTORMS ONGOING ACROSS NORTHERN
CWA. EXPECT SCATTERED CONVECTION TO CONTINUE IN THE KPKB/KCKB/KEKN
AREAS FOR A COUPLE MORE HOURS BEFORE WINDING DOWN AS THE FRONT DROPS
SOUTH. MVFR EXPECTED WITH HEAVIER SHOWERS AND AND POSSIBLE DROPS
INTO IFR IN STRONGER STORMS. UNCERTAINTY IS RATHER HIGH ON WEATHER
THE CONVECTIVE COMPLEX OVER IN/IL WILL MOVE ACROSS KHTS/KCRW/KBKW
LATER THIS EVENING. DID INCLUDE SOME MVFR AT THESE SITES...BUT WILL
HAVE TO WATCH HOW IT PLAYS OUT.
AS SHOWERS DECREASE AND MOVE OUT...MAY SEE FOG FORM IN COOLER AIR
BEHIND THE FRONT...BRINGING MVFR CEILINGS AND VISIBILITIES FROM
05-14Z...WITH IMPROVEMENT INTO VFR BY MID MORNING...THROUGH THE REST
OF SUNDAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z MONDAY...
FORECAST CONFIDENCE...LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING AND LOCATION OF HEAVIEST SHOWERS AND
STORMS AND ASSOCIATED DETERIORATING CONDITIONS MAY VARY FROM
FORECAST. POST FRONTAL CIGS AND FOG MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
CRW CONSISTENCY H H H M M M L M M M M L
HTS CONSISTENCY H H M M M M L H M M M L
BKW CONSISTENCY H H H H L L L L M M M L
EKN CONSISTENCY H L H H H M H H M M M L
PKB CONSISTENCY M M M L M M M L M M M L
CKB CONSISTENCY M M M L L H M L M M M L
AFTER 00Z MONDAY...
IFR IS POSSIBLE IN SHOWERS AND THUNDERSTORMS AT TIMES MONDAY NIGHT
THROUGH TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH SUNDAY MORNING FOR WVZ005>007-
013>015-024>026-033>036.
OH...FLASH FLOOD WATCH THROUGH SUNDAY MORNING FOR OHZ083-086-087.
KY...FLASH FLOOD WATCH THROUGH SUNDAY MORNING FOR KYZ101>103-105.
VA...NONE.
&&
$$
SYNOPSIS...KTB/JMV/30
NEAR TERM...JMV/MZ
SHORT TERM...TRM
LONG TERM...KTB
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS TULSA OK
727 PM CDT SAT APR 28 2012
.DISCUSSION...
LONG RANGE RADAR ECHOES FROM KINX ARE SHOWING HINTS THAT CONVECTION
IS TRYING TO DEVELOP TO THE SW OF OKC. MODEL SOUNDINGS SHOW THE
CAP WEAKENING AROUND AND AFTER 00Z...AND THIS WILL ALLOW FOR MORE
STORM DEVELOPMENT ALONG AND NORTH OF THE FRONT. THE LLJ IS
FORECAST TO STRENGTHEN TO THE SOUTH OF THE FRONT DURING THE
OVERNIGHT...ESPECIALLY OVER SW AND CNTRL OK. AS A RESULT...A
GRADUAL EXPANSION IN CONVECTIVE COVERAGE IS EXPECTED ACROSS N
CNTRL OK LATER THIS EVENING...WITH THIS ACTIVITY SPREADING
GENERALLY E/NE INTO NORTHEAST OK AROUND OR AFTER MIDNIGHT PER THE
MOST RECENT RUNS OF THE HRRR. THE ECMWF AND GFS ENSEMBLE DATA ALSO
SUPPORT THIS AS WELL. I HAVE RAISED POPS BASICALLY FROM THE I-44
CORRIDOR NORTHWARD INTO THE LIKELY CATEGORY. THE HRRR DOES ALSO
HINT THAT ONE OR TWO STORMS COULD REMAIN DISCRETE ON THE SOUTHERN
FRINGE OF THE CONVECTIVE CLUSTER...AND ANY POTENTIAL RIGHT MOVING
SUPERCELL WOULD MOVE MORE EAST THAN NORTH...AND COULD POTENTIALLY
AFFECT THE TULSA METRO AND SURROUNDING AREAS LATER. ANY RIGHT
MOVING SUPERCELL WOULD HAVE AT LEAST LIMITED TORNADO POTENTIAL
GIVEN THE STRENGTHENING 0-1KM SHEAR AND LOW LCLS TONIGHT. UPDATED
TEXT PRODUCTS OUT SHORTLY.
LACY
&&
.PREV DISCUSSION... /ISSUED 645 PM CDT SAT APR 28 2012/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CEILINGS CONTINUE TO BE OBSERVED ACROSS THE REGION LATE THIS
AFTERNOON WHILE A FRONTAL BOUNDARY REMAINED OVER FAR NORTHEAST
OKLAHOMA. THIS BOUNDARY LOOKS TO WAFFLE BETWEEN BVO AND TUL/RVS
THIS EVENING AND OVERNIGHT AND WILL BE THE FOCUS FOR CONVECTIVE
ACTIVITY...MAINLY AFFECTING NORTHEAST OKLAHOMA TAF SITES. FRONTAL
BOUNDARY SHOULD RETREAT NORTHWARD DURING THE DAY SUNDAY...ALLOWING
FOR SOUTHERLY WINDS TO BE COMMON ACROSS ALL TAF SITES. VFR
CONDITIONS SHOULD CONTINUE THROUGH THE EVENING...WITH MVFR
CONDITIONS CAPABLE WITHIN ANY CONVECTIVE DEVELOPMENT OVER
NORTHEAST OKLAHOMA. SOUTHEAST OKLAHOMA AND NORTHWEST ARKANSAS ARE
EXPECTED TO REMAIN VFR...THROUGH SOME EARLY MORNING MVFR CEILINGS
COULD BE POSSIBLE.
PREV DISCUSSION... /ISSUED 320 PM CDT SAT APR 28 2012/
DISCUSSION...
FRONTAL BOUNDARY HAS MOVED LITTLE TODAY AND IS CURRENTLY
NEAR A KBVO-KSWO LINE AND MAY MOVE A LITTLE TO THE SOUTH
AND EAST TONIGHT BEFORE RETREATING TO THE NORTH ON SUNDAY.
THE CAP IS WEAKENING ENOUGH ACROSS NORTHEAST OKLAHOMA THAT
A FEW SHOWERS AND THUNDERSTORMS COULD DEVELOP EARLY THIS
EVENING IN THE VICINITY OF THE FRONTAL BOUNDARY. THERE WILL
BE BETTER CHANCES OF SHOWERS AND THUNDERSTORMS LATER TONIGHT
AS A MID-LEVEL SHORTWAVE MOVES OUT OF THE SOUTHERN ROCKIES
AND ACROSS THE PLAINS AND ISENTROPIC LIFT INCREASES ACROSS THE
AREA. SOME OF THESE STORMS COULD BECOME STRONG TO SEVERE WITH
ELEVATED INSTABILITIES BECOMING MORE FAVORABLE. HAIL AND WINDS
WILL BE THE CONCERN. LOCALLY HEAVY RAIN WILL ALSO BE POSSIBLE
ALONG AND NORTH OF THE FRONTAL BOUNDARY LATE TONIGHT INTO
SUNDAY MORNING.
WITH A SOUTHWESTERLY FLOW ALOFT SUNDAY INTO MONDAY...THERE WILL
THE POTENTIAL FOR SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS
WITH THE BEST CHANCES SUNDAY NIGHT INTO MONDAY MORNING. LOCALLY
HEAVY RAIN WILL AGAIN BE POSSIBLE ACROSS PORTIONS OF NORTHEAST
OKLAHOMA ESPECIALLY IF THE FRONTAL BOUNDARY CAN REMAIN ACROSS
THE AREA. WILL END THE CHANCES OF SHOWERS AND THUNDERSTORMS
ON TUESDAY WITH THE UPPER LEVEL FLOW FLATTENING OUT ACROSS THE
AREA TEMPORARILY.
WILL KEEP THE REMAINDER OF THE FORECAST DRY. HOWEVER...ANOTHER FRONTAL
BOUNDARY WILL FLIRT WITH NORTHERN PORTIONS OF THE AREA ON THURSDAY
BEFORE RETURNING TO THE NORTH. AN UPPER LEVEL RIDGE WILL BUILD INTO
THE REGION NEXT WEEKEND KEEPING SHOWERS AND THUNDERSTORMS AT BAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 65 78 65 80 / 60 50 70 50
FSM 65 84 64 81 / 20 20 30 50
MLC 64 79 66 80 / 20 20 30 30
BVO 61 77 63 79 / 70 60 70 50
FYV 60 80 61 77 / 40 20 40 60
BYV 62 80 61 77 / 30 30 40 60
MKO 63 80 64 79 / 40 30 50 40
MIO 64 79 64 80 / 60 50 70 50
F10 64 78 66 79 / 40 30 50 30
HHW 63 81 65 81 / 10 10 20 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
731 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WEAK WAVE OF LOW PRESSURE WILL PASS SOUTH OF THE REGION LATER
TONIGHT. A LARGE AREA OF HIGH PRESSURE WILL NOSE SOUTHEAST FROM
THE GREAT LAKES SUNDAY...PROVIDING FAIR WEATHER AND MODERATING
TEMPERATURES INTO EARLY NEXT WEEK. WARMER WEATHER IS EXPECTED FOR
MUCH OF THE UPCOMING WORK WEEK AS AN UPPER RIDGE BECOMES ANCHORED
OVER THE SOUTHEAST STATES AND WESTERN ATLANTIC. AT THE SAME
TIME...THE PATTERN SHOULD BECOME MORE UNSETTLED WITH SEVERAL
OPPORTUNITIES FOR CONVECTIVE RAINFALL...ESPECIALLY DURING THE
MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
RADAR MOSAIC SHOWS SCATTERED VERY LIGHT RAINS SPREADING ACROSS THE
AREA. SURFACE OBS SHOW ANY PRECIP THAT IS REACHING THE GROUND AS
VERY SPOTTY WITH JUST TRACE AMOUNTS. HAVE BACKED OFF THE POPS
WHICH THE SREF STILL HAS AS VERY HIGH. THINKING BETWEEN NOW AND
MIDNIGHT IS THAT MOST AREAS WILL SEE LITTLE MORE THAN A FEW LIGHT
SPRINKLES OR PERHAPS A BRIEF SHOWER THAT LASTS LONG ENOUGH TO WET
THE GROUND IN A COUPLE OF LOCATIONS.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN NOW AND 02Z. DECREASING POPS WILL DEVELOP FROM
FROM NW TO SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END
TO THE RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE WILL PRESS STEADILY TO THE SE LATER TONIGHT THROUGH
THE PREDAWN HOURS OF SUNDAY.
TRANSITIONED FROM THE FREEZE WATCH TO A HARD FREEZE WARNING UP
NORTH...AND A FREEZE WARNING ACROSS THE REGION NEAR...AND TO THE
SOUTH OF INTERSTATE 80. THIS BLENDS WELL WITH SIMILAR PRODUCTS
ISSUED BY ADJACENT WFOS. MINS WILL RANGE FROM THE LOWER 20S ACROSS
THE NRN TIER...TO THE MID 30S ALONG THE MASON/DIXON LINE. TEMPS
COULD EASILY DIP INTO THE UPPER TEENS IN SOME OF THE NORMALLY COLD
RURAL VALLEYS UP NORTH BASED ON CURRENT AND UPSTREAM SFC DEWPOINTS.
AMPLE CLOUD COVER ACROSS SOUTHERN PENN UNTIL VERY EARLY SUNDAY
SHOULD PREVENT TEMPS FROM REACHING THE FREEZING MARK FOR AN
OVERNIGHT LOW...RATHER SETTLE BETWEEN 33-35F IN MOST LOCATIONS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
SUNNY SKIES WILL OCCUR IN ALL AREAS SUNDAY THANKS TO A STRONG
/1029MB/ AREA OF HIGH PRESSURE NOSING SE FROM THE GREAT LAKES. THE
VERY DRY LOW TO MID LEVEL AIR WILL MAKE IT TOUGH TO MAKE ANY CLOUDS
REACH THE CWA DESPITE A NNW FETCH OFF THE LOWER LAKES.
THE FRONTAL BOUNDARY DOES NOT MIGRATE TOO FAR TO THE SOUTH...AND MAY
BUBBLE UP TO THE NORTH AS A WARM FRONT WHICH COULD ENTER FAR SWRN
PA. A FEW BRIEF -SHRA COULD SNEAK TWD SOMERSET COUNTY LATE IN THE
DAY...BUT CONSIDERING THE DEPTH OF THE DRY AIR RESIDING OVER THE
LOCAL AREA...POPS WILL BE BASICALLY NIL THROUGH ALL OF SUNDAY.
HIGHS ON SUNDAY WILL CLIMB TO 8-13F HIGHER THAN TODAY...BUT WILL
STILL BE A LITTLE BELOW NORMAL - WHICH ARE NOW IN THE 60S - EVEN IN
THE NRN MTS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
A RIDGE BUILDING OVER THE REGION SUNDAY NIGHT WILL PROPAGATE
EASTWARD AS THE UPPER LEVEL LOW CONTINUES TO MOVE NORTHWARD. THIS
RIDGE WILL ALLOW FOR CLEARING SKIES SUNDAY NIGHT AND WARMER
TEMPERATURES...WITH 12C AT 850MB MONDAY AFTERNOON. THE WARMING
TREND WILL CONTINUE THROUGH MID WEEK DUE TO WARM SOUTHERLY FLOW.
THE RIDGE WILL FLATTEN AS A WEAK TROUGH MOVING THROUGH CENTRAL
CANADA LATE MONDAY...EARLY TUESDAY...COUPLING THE INSTABILITY WITH
MOIST FLOW SHOULD ALLOW FOR A TIME OF MCS-FAVORABLE CONDITIONS.
THIS SHOULD ALLOW FOR SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS
MONDAY EVENING...AND CONTINUING THROUGH TUESDAY MORNING. HAVE
INCREASED POPS ACCORDINGLY AND CURRENT MODEL EASTWARD PROGRESSION.
THE ZONAL FLOW THROUGH THE MIDDLE OF THE WEEK WILL ALLOW FOR ANY
SHORT WAVE RIPPLING THROUGH THE PATTERN TO BRING A CHANCE FOR
SHOWERS....MAINLY IN THE AFTERNOON. A DECENT GRADIENT THURSDAY MAY
ALLOW FOR GUSTIER WINDS. THE MODELS ARE IN AGREEMENT THROUGH
THURSDAY AS THE EC AND THE GFS BEGIN TO DIVERGE FRIDAY. THE EC
SPEEDS UP THE THE PROGRESSION OF THE UPPER LEVEL LOWS THROUGH THE
CENTRAL CONUS FRIDAY MORNING. THIS THEN ALLOWS THE TWO MODELS TO
BECOME OUT OF PHASE. BOTH MODELS KEEPS WARM AIR THROUGH THE AREA
THROUGH THE END OF THE WEEK...WITH COOLER TEMPS ADVECTING IN NEXT
WEEKEND. HAVE KEPT 30 POPS OVER MUCH OF THE REGION...ESPECIALLY
THE ELEVATED AREAS...THURSDAY AND FRIDAY. CURRENTLY THERE IS A LOW
PROBABILITY FOR ANY PRECIP NEXT WEEKEND.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
A SHIELD OF MAINLY MID AND HIGH CLOUDS WILL CONTINUE TO STREAM EAST
ACROSS THE REGION THROUGH AT LEAST THE FIRST HALF OF TONIGHT...BUT
VFR CONDS WILL PREVAIL AT MOST AIRFIELDS...EVEN DURING SOME
INTERMITTENT VERY LIGHT RAIN. A FEW SNOW PELLETS COULD BE MIXED IN
NEAR KJST AND EAST THROUGH KAOO WHERE TEMPS AOA 1500 AGL ARE NEAR TO
JUST BELOW ZERO C.
LOW PRES RIDING EWD FM THE MID MS VLY THRU THE MID-SOUTH WILL SPREAD
LOWER CIGS ACROSS CENTRAL AND SRN PA AIRFIELDS WITH LIGHT RAIN
LIKELY SOUTH OF DUJ-IPT LINE LATE THIS AFTN THROUGH THIS EVENING.
KIPT WILL BE ON THE NRN EDGE OF VERY LIGHT PRECIP THIS EVENING.
HOWEVER...THE LATEST BLEND OF THE 21Z RUC AND 18Z NAM QPF INDICATES
THAT ANY MEASURABLE RAINFALL WILL BE SOUTH OF INTERSTATE 80.
BORDERLINE MVFR CIGS ARE LIKELY OVR JST DURING THE FIRST PART OF THE
OVERNIGHT...BEFORE A DRYING NLY FLOW BRINGS IMPROVING CONDS AND
CLEARING SKIES BY DAYBREAK SUNDAY.
OUTLOOK...
SUN...VFR/NO SIG WX EXPECTED.
MON-THU...MAINLY VFR WITH SCT TSTM IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 2 AM TO 9 AM EDT SUNDAY FOR PAZ004>006-
010>012-037-041-042.
FREEZE WARNING FROM 3 AM TO 9 AM EDT SUNDAY FOR PAZ017>019-
024>028-045-046-049>053-058.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1053 AM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHWARD ACROSS NORTH CAROLINA THIS
MORNING...AND SHOULD STALL NEAR THE SOUTH CAROLINA BORDER THIS
AFTERNOON. THE FRONT IS EXPECTED TO LIFT BACK TO THE NORTH ON
SATURDAY BRIEFLY...BEFORE BEING DRIVEN BACK SOUTHWARD ON SUNDAY BY
HIGH PRESSURE MOVING ACROSS THE GREAT LAKES. THE FRONT WILL WASH OUT
EARLY NEXT WEEK AS THE HIGH MOVES OFF THE EAST COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...14Z SURFACE ANALYSIS INDICATES THAT A SURFACE
BOUNDARY LIES FROM NE GA..EAST ACROSS UPSTATE SC THROUGH THE
CHARLOTTE AREA. THE BOUNDARY SEPARATES LOW 60`S DEWPOINT AIR FROM
MIDDLE 50S OR SO TO THE NORTH. THIS BOUNDARY SHOULD SERVE AS A FOCUS
FOR AFTERNOON CONVECTION. MESO MODELS INDICATE THAT SHOWERS AND
THUNDERSTORMS WILL MOVE EAST OUT OF NORTHERN GA INTO THE WESTERN
UPSTATE BY 18Z AND THEN ACROSS THE REMAINDER OF THE UPSTATE INTO NC
AROUND THE SOUTHERN SUBURBS OF CHARLOTTE. WILL ADJUST THE POP FIELD
TO INCREASE COVERAGE OF SHOWERS/STORMS INTO THE NUMEROUS CATEGORY
OVER A LARGE PORTION OF NE GA AND THE SC UPSTATE. WILL SHOW SCT TYPE
COVERAGE NORTH TO AROUND THE NC BORDER. NAM BUBBLES UP CAPES TO
NEAR 2000J/KG THIS AFTERNOON ACROSS UPSTATE SC...SO A COUPLE
SEVERE STORMS WITH LARGE HAIL NOT OUT OF TEH QUESTION.
ALSO...12Z NAM AND OTHER MESO MODELS INDICATE A SOMEWHAT TRANSIENT
CLUSTER OF SHOWERS/STORMS THIS AFTERNOON INTO THE EVENING ASSOCIATED
WITH AN UPPER VORT. HENCE...WILL FOLLOW THE LEAD OF THE NAM AND MOVE
POPS OUT OF THE FORECAST AREA THIS EVENING AS A NE FLOW/WEDGE
DEVELOPS OVERNIGHT. THE NAM DOES NOT GENERATE ANY QPF TONIGHT INTO
SAT...SO WILL KEEP MENTIONABLE POPS OUT. EXPECT MOSTLY CLOUDY
CONDITIONS TO DEVELOP BY LATE AFTERNOON CONTINUING INTO SAT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...THE SHORT RANGE REMAINS IN A STATE OF FLUX
BECAUSE OF UNCERTAINTY WITH THE PLACEMENT OF THE SURFACE BOUNDARY.
THE RELATIVELY FLAT UPPER FLOW ACROSS MUCH OF THE SOUTHEAST WILL
BUCKLE OVER TIME...WITH AN AMPLIFYING UPPER RIDGE...AS THE OMEGA
BLOCK TO OUR NORTH DISINTEGRATES SUNDAY AND INTO MONDAY. THERE DOES
NOT APPEAR TO BE MUCH IN THE WAY OF UPPER FORCING...BUT A SURFACE
BOUNDARY WILL PROVIDE LOW LEVEL FORCING AND FOCUS FOR CONVECTIVE
DEVELOPMENT...FIRST ON SATURDAY EARLY IN THE DAY AS IT MOVES
NORTHWARD AS A WARM FRONT. HAVE RAISED PRECIP CHANCES AND CLOUD
COVER A BIT OVER THE NORTHERN ZONES BASED ON THE SREF. A
CORRESPONDING DOWNWARD ADJUSTMENT TO MAX TEMPS WAS ALSO MADE. AFTER
A RELATIVELY QUIET SATURDAY NIGHT...THE FRONT IS EXPECTED TO BE
DRIVEN BACK SOUTHWARD BY THE NEXT SURFACE HIGH MOVING OVER THE
WESTERN GREAT LAKES...BUT PERHAPS NOT UNTIL LATE IN THE DAY. THE
MODEL GUIDANCE WAS ALL UNIFORMLY QUITE A BIT WARMER THAN THE
PREVIOUS FCST BECAUSE OF THE LATER TIMING...SO AN UPWARD ADJUSTMENT
OF ONE OR TWO CATEGORIES WAS MADE. THIS COULD EASILY GO WRONG AND BE
COOLER IF THE TIMING OF THE FRONT IS EARLIER THAN PLANNED. HAVE ALSO
RAISED MIN TEMPS SUNDAY NIGHT WITH INCREASED CLOUD COVER.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...NOT MUCH IN THE LATEST OPERATIONAL MODELS IS
FOUND COMPELLING ENOUGH TO MAKE ANY SIGNIFICANT CHANGES TO THE
MEDIUM RANGE. AT LEAST THROUGH MID WEEK WE SHOULD BE UNDER THE
INFLUENCE OF UPPER RIDGING THAT WILL KEEP THE BEST UPPER FORCING TO
OUR NORTH...WITH THE WESTERN CAROLINAS ESSENTIALLY IN A WARM SECTOR.
THAT SHOULD FAVOR LOW CHANCES OF MAINLY DIURNAL CONVECTIVE PRECIP.
THE GFS DEVELOPS IN INTERESTING UPPER LOW LATE IN THE WEEK OVER THE
SOUTHEAST WHICH WOULD MEAN A BETTER CHANCE OF PRECIP...BUT THAT
FEATURE IS WELL OFFSHORE ON THE ECMWF...SO WE WILL NOT BITE ON IT.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...A TRICKY FCST FOR VSBY THIS MORNING. LOW TDD/S AND CALM
CONDS WILL MAKE AN MVFR BR POSSIBLE FOR THE FIRST COUPLE HRS OF THE
PERIOD. LEFT OUT OF TAF BASED ON 10SM OCCURRING RIGHT NOW AND THE
POTENTIAL FOR WINDS TO PICK UP A TAD AFT 12Z. AFTERNOON CONVECTION
LOOKS TO BE CLOSE TO THE TERMINAL. SHARP BOUNDARY JUST TO THE
SOUTH...WITH HRRR SHOWING STORMS RIDING ON AND TO THE N OF THE
BOUNDARY AND PERHAPS IMPINGING UPON THE AREA AROUND 20Z. WILL LEAVE
VCTS OUT OF THE TAF PER COORDINATION WITH CWSU. WARM FRONT MOVES
OVER WEDGE TONIGHT AND MVFR CIGS WILL BE POSSIBLE AFT 09Z AS WEDGE
BOUNDARY SHIFTS NE.
ELSEWHERE...TOUGH CALL ON THE MTN VSBY THIS MORNING WITH WINDS
PICKING UP AND THEN SETTLING DOWN. WILL KEEP THE IFR MENTION AT KAVL
THROUGH 14Z. OTHER SITES...IT LOOKS LIKE VFR CIGS/VSBY THROUGH THE
MORNING WILL PREVAIL. EXPECT VCTS THIS AFTERNOON ACROSS THE NON/NC
SITES. STATIONARY FRONT WILL MOVE LITTLE AND MAKE FOR A GOOD AREA OF
CONVECTIVE DEVELOPMENT.
OUTLOOK...A FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF THE AREA
THROUGH THE WEEKEND...RESULTING IN CONTINUATION OF UNSETTLED
WEATHER/PM SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS THROUGH THAT
TIME.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...PM
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
724 AM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHWARD ACROSS NORTH CAROLINA THIS
MORNING...AND SHOULD STALL NEAR THE SOUTH CAROLINA BORDER THIS
AFTERNOON. THE FRONT IS EXPECTED TO LIFT BACK TO THE NORTH ON
SATURDAY BRIEFLY...BEFORE BEING DRIVEN BACK SOUTHWARD ON SUNDAY BY
HIGH PRESSURE MOVING ACROSS THE GREAT LAKES. THE FRONT WILL WASH OUT
EARLY NEXT WEEK AS THE HIGH MOVES OFF THE EAST COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
0715 AM UPDATE...MADE SOME MINOR ADJUSTMENTS TO TEMP/DEWPOINT TRENDS
AND LOWERED POPS SOUTHERN PERIPHERY. WILL ALSO BE CANCELLING THE
DENSE FOG ADVISORY AS WINDS HAVE PICKED UP ACROSS THE FRENCH BROAD
VALLEY AND MIXED FOG OUT.
AS OF 330 AM...THE LATEST LAPS ANALYSIS SHOWS THE COLD FRONT LOCATED
STILL LOCATED TO THE NW OF THE CWFA WITH GOOD MOISTURE POOLING AHEAD
ACROSS ERN TN AND INTO THE WRN NC MTNS. THIS HAS HELPED MAINTAIN
ISOL/SCT -SHRA ACROSS THE WRN ZONES. THIS ACTIVITY SHOULD WANE
THROUGH MORNING AS THE PRESSURE TROF BROADENS AND SILENTLY PUSHES
SOUTH. MORNING FG IS SETTING UP WHERE EXPECTED...MAINLY ACROSS THE
WRN HALF OF THE CWFA WHERE MOST OF THE RAIN FELL YESTERDAY. NOTHING
TOO WIDESPREAD AS FAR AS DENSE FG...BUT THIS WILL BE MONITORED AS
TDDS ARE PRETTY LOW ADJACENT TO THE MTNS AND SC PIEDMONT. EXPECT THE
MAIN TSTM ACTIVITY TO INSTIGATE WITHIN THE PRESSURE TROF...WHICH
WILL BE ACROSS THE UPSTATE INTO NE GA. THE NC ZONES SHOULD BECOME
UNDER THE INFLUENCE OF NE/LY FLOW AND LOWER TD/S MAKING FOR A MORE
STABLE ENVIRONMENT. THUS...POPS ARE THE HIGH END CHANCE AND
GENERALLY APPLIED ONLY TO THE SC/GA ZONES THIS AFTERNOON. SBCAPE
VALUES WILL BE MODERATE AND LLVL SHEAR LOW...WITH DECENT BULK
SHEAR...SO THE STAGE WILL BE SET ONCE MORE FOR SOME STRONG TO SEVERE
STORMS AGAIN THIS AFTERNOON. WITH THE FRONT STALLING OUT ACROSS THE
NRN UPSTATE...HIGHS TWILL RANGE FROM THE M70S ACROSS THE NRN NC
PIEDMONT TO THE L80S ACROSS THE LOWER UPSTATE. MTN VALLEYS WILL
REACH THE L70S.
A WEAK BUT NOTICEABLE SFC WEDGE BEGINS TO FORM LATE THIS AFTERNOON
AND EVENING. AT THE SAME TIME A DEEPENING SFC LOW WILL MOVE
NORTHEAST INTO THE LOWER MIDWEST AND THIS WILL PULL THE STATIONARY
FRONT OVER THE WEDGE. WITH GOOD MOISTURE...LIGHT TO MODERATE SHOWERS
SHOULD DEVELOP ACROSS THE NC ZONES AND THE ATMOS WILL BE TOO STABLE
FOR ANY REAL CONVECTIVE THREAT. WITH CLOUD COVER REMAINING FAIRLY
HIGH...LOWS WILL ONLY DROP INTO THE M50S TO AROUND 60 NON/MTNS AND
L50S MTN VALLEYS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...THE SHORT RANGE REMAINS IN A STATE OF FLUX
BECAUSE OF UNCERTAINTY WITH THE PLACEMENT OF THE SURFACE BOUNDARY.
THE RELATIVELY FLAT UPPER FLOW ACROSS MUCH OF THE SOUTHEAST WILL
BUCKLE OVER TIME...WITH AN AMPLIFYING UPPER RIDGE...AS THE OMEGA
BLOCK TO OUR NORTH DISINTEGRATES SUNDAY AND INTO MONDAY. THERE DOES
NOT APPEAR TO BE MUCH IN THE WAY OF UPPER FORCING...BUT A SURFACE
BOUNDARY WILL PROVIDE LOW LEVEL FORCING AND FOCUS FOR CONVECTIVE
DEVELOPMENT...FIRST ON SATURDAY EARLY IN THE DAY AS IT MOVES
NORTHWARD AS A WARM FRONT. HAVE RAISED PRECIP CHANCES AND CLOUD
COVER A BIT OVER THE NORTHERN ZONES BASED ON THE SREF. A
CORRESPONDING DOWNWARD ADJUSTMENT TO MAX TEMPS WAS ALSO MADE. AFTER
A RELATIVELY QUIET SATURDAY NIGHT...THE FRONT IS EXPECTED TO BE
DRIVEN BACK SOUTHWARD BY THE NEXT SURFACE HIGH MOVING OVER THE
WESTERN GREAT LAKES...BUT PERHAPS NOT UNTIL LATE IN THE DAY. THE
MODEL GUIDANCE WAS ALL UNIFORMLY QUITE A BIT WARMER THAN THE
PREVIOUS FCST BECAUSE OF THE LATER TIMING...SO AN UPWARD ADJUSTMENT
OF ONE OR TWO CATEGORIES WAS MADE. THIS COULD EASILY GO WRONG AND BE
COOLER IF THE TIMING OF THE FRONT IS EARLIER THAN PLANNED. HAVE ALSO
RAISED MIN TEMPS SUNDAY NIGHT WITH INCREASED CLOUD COVER.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...NOT MUCH IN THE LATEST OPERATIONAL MODELS IS
FOUND COMPELLING ENOUGH TO MAKE ANY SIGNIFICANT CHANGES TO THE
MEDIUM RANGE. AT LEAST THROUGH MID WEEK WE SHOULD BE UNDER THE
INFLUENCE OF UPPER RIDGING THAT WILL KEEP THE BEST UPPER FORCING TO
OUR NORTH...WITH THE WESTERN CAROLINAS ESSENTIALLY IN A WARM SECTOR.
THAT SHOULD FAVOR LOW CHANCES OF MAINLY DIURNAL CONVECTIVE PRECIP.
THE GFS DEVELOPS IN INTERESTING UPPER LOW LATE IN THE WEEK OVER THE
SOUTHEAST WHICH WOULD MEAN A BETTER CHANCE OF PRECIP...BUT THAT
FEATURE IS WELL OFFSHORE ON THE ECMWF...SO WE WILL NOT BITE ON IT.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT...A TRICKY FCST FOR VSBY THIS MORNING. LOW TDD/S AND CALM
CONDS WILL MAKE AN MVFR BR POSSIBLE FOR THE FIRST COUPLE HRS OF THE
PERIOD. LEFT OUT OF TAF BASED ON 10SM OCCURRING RIGHT NOW AND THE
POTENTIAL FOR WINDS TO PICK UP A TAD AFT 12Z. AFTERNOON CONVECTION
LOOKS TO BE CLOSE TO THE TERMINAL. SHARP BOUNDARY JUST TO THE
SOUTH...WITH HRRR SHOWING STORMS RIDING ON AND TO THE N OF THE
BOUNDARY AND PERHAPS IMPINGING UPON THE AREA AROUND 20Z. WILL LEAVE
VCTS OUT OF THE TAF PER COORDINATION WITH CWSU. WARM FRONT MOVES
OVER WEDGE TONIGHT AND MVFR CIGS WILL BE POSSIBLE AFT 09Z AS WEDGE
BOUNDARY SHIFTS NE.
ELSEWHERE...TOUGH CALL ON THE MTN VSBY THIS MORNING WITH WINDS
PICKING UP AND THEN SETTLING DOWN. WILL KEEP THE IFR MENTION AT KAVL
THROUGH 14Z. OTHER SITES...IT LOOKS LIKE VFR CIGS/VSBY THROUGH THE
MORNING WILL PREVAIL. EXPECT VCTS THIS AFTERNOON ACROSS THE NON/NC
SITES. STATIONARY FRONT WILL MOVE LITTLE AND MAKE FOR A GOOD AREA OF
CONVECTIVE DEVELOPMENT.
OUTLOOK...A FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF THE AREA
THROUGH THE WEEKEND...RESULTING IN CONTINUATION OF UNSETTLED
WEATHER/PM SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS THROUGH THAT
TIME.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NCZ053-064-
065.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...SBK/LG
SHORT TERM...PM
LONG TERM...PM
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
650 AM CDT FRI APR 27 2012
.UPDATE...
12Z TAF DISCUSSION.
&&
.AVIATION...
COLD FRONT HAS PUSHED SOUTHWARD TO NEAR THE ALABAMA BORDER WITH
MUCH COOLER AND DRIER AIR NOW HAVING FILTERED BEHIND THE
BOUNDARY. LATEST HRRR AND 4 KM WRF INDICATE A FEW SHRA OR
POSSIBLY A TSRA WILL BE POSSIBLE AT AREA AIRPORTS IN THE 20-02Z
TIMEFRAME...BUT CONFIDENCE IS LOW. WILL MENTION VCSH DURING THE
LATE AFTERNOON/EARLY EVENING TIME PERIOD FOR NOW AND KEEP
CONDITIONS VFR AT CKV/BNA/CSV. WINDS WILL BE OUT OF THE NORTHEAST
THIS MORNING GRADUALLY VEERING TO SOUTHEASTERLY BY FRIDAY
NIGHT...WITH SPEEDS GENERALLY 10 KTS OR LESS.
&&
.PREV DISCUSSION... /ISSUED 355 AM CDT FRI APR 27 2012/
SHORT TERM (FRI-SUN)...
SFC HIGH PRES WL PREVAIL ACROSS THE OHVLY WITH PLENTY OF CLOUDS
AND COOLER TEMPS TDAY. MODELS DO A GOOD JOB KEEPING A STALLED
COLD FRONT NEAR THE AL-TN BORDER THIS AFTN. EXPECT HIGHS NEAR 70
DEGREES NORTH. SOUTHWEST FLOW ALOFT/DEEPER MOISTURE WL STREAM OVR
THE BOUNDARY THIS AFTN...WITH A CHANCE OF SHOWERS ACROSS THE
REGION.
TNGT...SFC LOW PRES IN THE SOUTHERN PLAINS WL DEVELOP NORTH INTO
MO TNGT. SYSTEM WL PUSH A WARM FRONT NORTH ACROSS MID TN TNGT...
WITH ONLY A FEW SHOWERS POSSIBLE NORTH.
SAT...WARMER TEMPS WITH WEAK H5 RIDGING EXPECTED. MANY LOCATIONS
EXPECTED TO HIT THE MID 80S. FOCUS FOR STORMS WL BE NORTH OF THE
AREA NEAR THE WARM FRONT IN KENTUCKY.
SAT NGT-SUN...SFC HIGH PRES IN THE GREAT LAKES MAY PUSH THE FNTL
BDRY BACK SOUTH INTO MID TN. ENSEMBLE MEAN GFS/EURO KEEP DEEPER
MOISTURE AND FRONTAL ZONE NORTH...WITH WEAK H5 RIDGING HOLDING ON
WITH DRY CONDITIONS SOUTH. WL ADVERTISE SCHC THUNDER POPS NORTH
MID TN.
LONG TERM (MON-THU)...
CONTINUED WARM MON. H5 RIDGE WEAKENS WITH AN INCREASE IN POPS MON
NGT-TUE. COULD BE SOME STRONG STORMS WITH MODEL SHOWALTERS TO -3.
UPPER RIDGE BUILDS BACK FOR A FEW DAYS W/POSSIBLE H5 CUTOFF LOW IN
SOUTHEASTERN STATES IN THE FAR EXTENDED AS PER GFS. WL NOT BUY
INTO A WET PERIOD AT THIS TIME. WL KEEP THE WARM PATTERN.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
858 PM CDT SAT APR 28 2012
.UPDATE...
A FEW THUNDERSTORMS HAVE DEVELOPED NEAR A RETREATING SURFACE
BOUNDARY STRETCHING FROM WEST OF THE CWA INTO OKLAHOMA. THE
STRONGEST STORM IS CURRENTLY LOCATED NEAR ASPERMONT AND IS MOVING
TO THE EAST AROUND 20-25 MPH. CURRENT EXTRAPOLATION WOULD BRING
THIS CELL INTO STEPHENS/YOUNG COUNTY AROUND MIDNIGHT...BUT DO NOT
ANTICIPATE IT HOLDING ITS STRENGTH FOR THE NEXT 3 HOURS AS CIN IS
EXPECTED TO INCREASE. ALSO...DO NOT EXPECT ITS MOVEMENT TO REMAIN
EAST. AS THE STORM WEAKENS...ITS FORWARD MOVEMENT WILL BECOME MORE
NORTHEASTERLY. CURRENT POP CONFIGURATION STILL LOOKS FINE...WITH
20 POPS NORTH OF AN EASTLAND TO DECATUR TO SHERMAN LINE. WILL ONLY
MAKE MINOR ADJUSTMENTS TO THE HOURLY GRIDS.
85/NH
&&
.AVIATION...
FOR THE 00Z TAFS...TIMING THE ONSET OF MVFR STRATUS IS THE PRIMARY
FORECAST CONCERN THROUGH THE VALID FORECAST PERIOD.
DID NOT MAKE MUCH IN THE WAY OF CHANGES TO PREVIOUS FORECAST.
BACKED UP THE ONSET OF STRATUS OVER METROPLEX AREA TAF SITES BY AN
HOUR BASED ON RUC FORECAST SOUNDINGS. OTHERWISE AGREE THAT STRATUS
WILL LIKELY HOLD ABOVE 2 KFT FOR METROPLEX AREA TAF SITES AND
SHOULD CLIMB 3 KFT BEFORE SCATTERING OUT TOMORROW MORNING. WACO
WILL GET INTO THE STRATUS A BIT EARLIER AND CIGS SHOULD HOLD A FEW
HUNDRED FEET LOWER THAN METROPLEX AREA TAF SITES. CONDITIONS WILL
ALSO LIKELY RETURN TO VFR AN HOUR OR SO LATER THAN METROPLEX AREA
SITES.
ONCE AGAIN THINK THAT THUNDERSTORM ACTIVITY WILL REMAIN WELL OFF
TO THE NORTHWEST OF THE METROPLEX OVER THE NEXT 24 TO 36 HRS AND
HAVE NOT INCLUDED ANY MENTION OF TSTM ACTIVITY IN THE TAFS. THE
SURFACE BOUNDARY NEAR WICHITA FALLS IS ACTUALLY EXPECTED TO
RETREAT TO THE NORTHWEST OVERNIGHT AND AS THIS IS EXPECTED TO PLAY
A KEY ROLE IN TSTM INITIATION...DO NOT THINK THAT ANY TSTM
ACTIVITY WILL BE ABLE TO AFFECT AREA TAF SITES.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 252 PM CDT SAT APR 28 2012/
A SHORTWAVE ROTATING AROUND THE UPPER LEVEL LOW IN THE NORTHERN
PLAINS IS NOW MOVING INTO THE TEXAS AND OKLAHOMA PANHANDLES.
MEANWHILE A FRONT HAS STALLED JUST NW OF THE CWA BORDER...ALONG A
LINE FROM ABI-SPS-OKC. CIN REMAINS HIGH DUE TO A STRONG INVERSION
NEAR 800MB...BUT WILL BEGIN TO LIFT/ERODE ACROSS THE NW ZONES LATE
THIS AFTERNOON AND EVENING AS FORCING FROM THE SHORTWAVE ARRIVES.
ALTHOUGH CONVERGENCE ALONG THE FRONTAL BOUNDARY IS FAIRLY WEAK ON
THE TEXAS SIDE...EXPECT A FEW STORMS TO DEVELOP BY EARLY EVENING.
STORM MOTION WILL BE GENERALLY TO THE NORTHEAST AND THUS WILL KEEP
THE LOW POPS RESTRICTED TO JUST THE NW ZONES TONIGHT. DEEP LAYER
SHEAR OF 35KT AND SBCAPE OF UP TO 2000 J/KG SUGGESTS STORM MODE
WILL WAFFLE BETWEEN MULTICELL AND BRIEF SUPERCELL. A LOW SEVERE
THREAT IS POSSIBLE IN THE FAR NW ZONES THIS EVENING...WITH HAIL
AND DAMAGING WINDS THE PRIMARY HAZARD. OTHERWISE...SOUTH WINDS
OF 10-20 MPH WILL ENSURE ANOTHER MILD NIGHT ACROSS NORTH TEXAS
WITH LOW STRATUS ARRIVING AFTER MIDNIGHT. MID-HIGH MOISTURE/CLOUDS
WILL ALSO BE ON THE INCREASE FROM THE SOUTHWEST AND WE MAY SEE
SOME RADAR ECHOES FROM VIRGA MOVE ACROSS THE REGION TONIGHT.
MORE ABUNDANT CLOUD COVER TOMORROW WILL HELP KEEP HIGH TEMPS A
COUPLE OF DEGREES COOLER THAN TODAY. ANOTHER SHORTWAVE WILL MOVE
THROUGH THE SOUTHERN PLAINS SUNDAY NIGHT. MOST OF THE CONVECTION
SUNDAY AFTERNOON AND EVENING WILL BE ACROSS OKLAHOMA...BUT SOME
OF THIS ACTIVITY MAY WANDER INTO THE NW ZONES WITH THE AID OF
CONVECTIVE OUTFLOWS. THE CAP WILL REMAIN TOO STRONG OVER THE
REMAINDER OF NORTH TEXAS THROUGH SUNDAY NIGHT FOR A MENTION OF
POPS. HOWEVER...FORCING FROM THE SHORTWAVE MAY LIFT THE CAP JUST
ENOUGH NORTH OF I-20 BY MONDAY MORNING FOR THE NORTHERN HALF OF
THE CWA TO HAVE A LOW CHANCE OF RAIN MONDAY WITH DAY-TIME HEATING.
THE REMAINDER OF THE FORECAST IS RATHER BENIGN AS THE UPPER LEVEL
PATTERN BECOMES STATIC WITH WEAK TROUGHING ACROSS THE NORTHERN
ROCKIES. THIS WILL KEEP A MOIST SOUTHERLY FLOW AT 15 TO 20 MPH IN
PLACE. EXPECT MILD OVERNIGHT LOWS IN THE MID-UPPER 60S WITH LATE
NIGHT AND MORNING LOW CLOUDS. AFTERNOONS WILL FEATURE SUNSHINE AND
HIGHS IN THE MID-UPPER 80S...BUT CAP LOOKS STRONG ENOUGH TO
PRECLUDE MENTIONING ANY RAIN CHANCES. MODELS ARE STILL STRUGGLING
TO RESOLVE UPPER LEVEL FEATURES BY THE END OF THE FORECAST PERIOD.
THE GFS IS NOW AN OUTLIER AS IT SHOWS STRONGER UPPER RIDGING AND A
WEAK FRONT BY SATURDAY. WILL SIDE WITH THE OTHER MODELS AND KEEP
THE WARM/DRY PERSISTENCE TREND IN PLACE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 67 84 69 86 69 / 10 10 10 20 10
WACO, TX 69 84 69 86 69 / 5 10 10 10 10
PARIS, TX 65 82 66 82 66 / 10 10 10 20 10
DENTON, TX 65 83 67 85 68 / 10 10 20 20 10
MCKINNEY, TX 65 83 67 84 67 / 10 10 10 20 10
DALLAS, TX 68 84 69 85 69 / 10 10 10 20 10
TERRELL, TX 66 83 69 84 68 / 5 10 10 20 10
CORSICANA, TX 67 84 69 85 68 / 5 10 10 10 10
TEMPLE, TX 69 85 69 86 68 / 5 10 10 10 10
MINERAL WELLS, TX 66 83 66 86 67 / 10 20 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
644 PM CDT SAT APR 28 2012
.AVIATION...
FOR THE 00Z TAFS...TIMING THE ONSET OF MVFR STRATUS IS THE PRIMARY
FORECAST CONCERN THROUGH THE VALID FORECAST PERIOD.
DID NOT MAKE MUCH IN THE WAY OF CHANGES TO PREVIOUS FORECAST.
BACKED UP THE ONSET OF STRATUS OVER METROPLEX AREA TAF SITES BY AN
HOUR BASED ON RUC FORECAST SOUNDINGS. OTHERWISE AGREE THAT STRATUS
WILL LIKELY HOLD ABOVE 2 KFT FOR METROPLEX AREA TAF SITES AND
SHOULD CLIMB 3 KFT BEFORE SCATTERING OUT TOMORROW MORNING. WACO
WILL GET INTO THE STRATUS A BIT EARLIER AND CIGS SHOULD HOLD A FEW
HUNDRED FEET LOWER THAN METROPLEX AREA TAF SITES. CONDITIONS WILL
ALSO LIKELY RETURN TO VFR AN HOUR OR SO LATER THAN METROPLEX AREA
SITES.
ONCE AGAIN THINK THAT THUNDERSTORM ACTIVITY WILL REMAIN WELL OFF
TO THE NORTHWEST OF THE METROPLEX OVER THE NEXT 24 TO 36 HRS AND
HAVE NOT INCLUDED ANY MENTION OF TSTM ACTIVITY IN THE TAFS. THE
SURFACE BOUNDARY NEAR WICHITA FALLS IS ACTUALLY EXPECTED TO
RETREAT TO THE NORTHWEST OVERNIGHT AND AS THIS IS EXPECTED TO PLAY
A KEY ROLE IN TSTM INITIATION...DO NOT THINK THAT ANY TSTM
ACTIVITY WILL BE ABLE TO AFFECT AREA TAF SITES.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 252 PM CDT SAT APR 28 2012/
A SHORTWAVE ROTATING AROUND THE UPPER LEVEL LOW IN THE NORTHERN
PLAINS IS NOW MOVING INTO THE TEXAS AND OKLAHOMA PANHANDLES.
MEANWHILE A FRONT HAS STALLED JUST NW OF THE CWA BORDER...ALONG A
LINE FROM ABI-SPS-OKC. CIN REMAINS HIGH DUE TO A STRONG INVERSION
NEAR 800MB...BUT WILL BEGIN TO LIFT/ERODE ACROSS THE NW ZONES LATE
THIS AFTERNOON AND EVENING AS FORCING FROM THE SHORTWAVE ARRIVES.
ALTHOUGH CONVERGENCE ALONG THE FRONTAL BOUNDARY IS FAIRLY WEAK ON
THE TEXAS SIDE...EXPECT A FEW STORMS TO DEVELOP BY EARLY EVENING.
STORM MOTION WILL BE GENERALLY TO THE NORTHEAST AND THUS WILL KEEP
THE LOW POPS RESTRICTED TO JUST THE NW ZONES TONIGHT. DEEP LAYER
SHEAR OF 35KT AND SBCAPE OF UP TO 2000 J/KG SUGGESTS STORM MODE
WILL WAFFLE BETWEEN MULTICELL AND BRIEF SUPERCELL. A LOW SEVERE
THREAT IS POSSIBLE IN THE FAR NW ZONES THIS EVENING...WITH HAIL
AND DAMAGING WINDS THE PRIMARY HAZARD. OTHERWISE...SOUTH WINDS
OF 10-20 MPH WILL ENSURE ANOTHER MILD NIGHT ACROSS NORTH TEXAS
WITH LOW STRATUS ARRIVING AFTER MIDNIGHT. MID-HIGH MOISTURE/CLOUDS
WILL ALSO BE ON THE INCREASE FROM THE SOUTHWEST AND WE MAY SEE
SOME RADAR ECHOES FROM VIRGA MOVE ACROSS THE REGION TONIGHT.
MORE ABUNDANT CLOUD COVER TOMORROW WILL HELP KEEP HIGH TEMPS A
COUPLE OF DEGREES COOLER THAN TODAY. ANOTHER SHORTWAVE WILL MOVE
THROUGH THE SOUTHERN PLAINS SUNDAY NIGHT. MOST OF THE CONVECTION
SUNDAY AFTERNOON AND EVENING WILL BE ACROSS OKLAHOMA...BUT SOME
OF THIS ACTIVITY MAY WANDER INTO THE NW ZONES WITH THE AID OF
CONVECTIVE OUTFLOWS. THE CAP WILL REMAIN TOO STRONG OVER THE
REMAINDER OF NORTH TEXAS THROUGH SUNDAY NIGHT FOR A MENTION OF
POPS. HOWEVER...FORCING FROM THE SHORTWAVE MAY LIFT THE CAP JUST
ENOUGH NORTH OF I-20 BY MONDAY MORNING FOR THE NORTHERN HALF OF
THE CWA TO HAVE A LOW CHANCE OF RAIN MONDAY WITH DAY-TIME HEATING.
THE REMAINDER OF THE FORECAST IS RATHER BENIGN AS THE UPPER LEVEL
PATTERN BECOMES STATIC WITH WEAK TROUGHING ACROSS THE NORTHERN
ROCKIES. THIS WILL KEEP A MOIST SOUTHERLY FLOW AT 15 TO 20 MPH IN
PLACE. EXPECT MILD OVERNIGHT LOWS IN THE MID-UPPER 60S WITH LATE
NIGHT AND MORNING LOW CLOUDS. AFTERNOONS WILL FEATURE SUNSHINE AND
HIGHS IN THE MID-UPPER 80S...BUT CAP LOOKS STRONG ENOUGH TO
PRECLUDE MENTIONING ANY RAIN CHANCES. MODELS ARE STILL STRUGGLING
TO RESOLVE UPPER LEVEL FEATURES BY THE END OF THE FORECAST PERIOD.
THE GFS IS NOW AN OUTLIER AS IT SHOWS STRONGER UPPER RIDGING AND A
WEAK FRONT BY SATURDAY. WILL SIDE WITH THE OTHER MODELS AND KEEP
THE WARM/DRY PERSISTENCE TREND IN PLACE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 67 84 69 86 69 / 10 10 10 20 10
WACO, TX 69 84 69 86 69 / 5 10 10 10 10
PARIS, TX 65 82 66 82 66 / 10 10 10 20 10
DENTON, TX 65 83 67 85 68 / 10 10 20 20 10
MCKINNEY, TX 65 83 67 84 67 / 10 10 10 20 10
DALLAS, TX 68 84 69 85 69 / 10 10 10 20 10
TERRELL, TX 66 83 69 84 68 / 5 10 10 20 10
CORSICANA, TX 67 84 69 85 68 / 5 10 10 10 10
TEMPLE, TX 69 85 69 86 68 / 5 10 10 10 10
MINERAL WELLS, TX 66 83 66 86 67 / 10 20 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1139 PM CDT THU APR 26 2012
.AVIATION...
LOW STRATUS HAS DEVELOPED AT KCDS BUT IS NOT EXPECTED TO PERSIST
FOR MORE THAN A FEW HOURS. OTHERWISE...SOUTHEASTERLY WINDS WILL
REMAIN BREEZY THROUGH THE EARLY MORNING HOURS. A COLD FRONT WILL
QUICKLY MOVE THROUGH THE AREA BEFORE DAYBREAK SHIFTING WINDS TO
THE WEST AND INCREASING SPEEDS. THESE WINDS WILL DECREASE NEAR
SUNSET ON FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 819 PM CDT THU APR 26 2012/
UPDATE...
REMAINING OUTFLOW BOUNDARIES FROM PREVIOUS CONVECTION WAS
UNSUCCESSFUL IN INITIATING STORMS. LIFT FROM THE TROUGH HAS MOVED
EAST AND NORTH OF THE AREA. REMAINING LIFT FROM THE TROUGH IS
EXPECTED TO SKIRT NORTH OF THE AREA LATER TONIGHT INTO EARLY
FRIDAY. HAVE ALSO UPDATED THE REST OF THE FORECAST TO MAINLY
REMOVE POPS.
PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 26 2012/
SHORT TERM...
MOIST EASTERLY FLOW THIS AFTERNOON WILL TURN 180 DEGREES BY TOMORROW
MORNING AND DRY OUT BEHIND A DRYLINE AND WEAK PACIFIC COLD FRONT.
UNTIL THEN...THE FORECAST CHALLENGE REMAINS FOCUSED ON TSTRM
OPPORTUNITIES LATE THIS AFTN AND EVENING WITHIN A FAVORABLY MOIST
AND DESTABILIZING ATMOSPHERE. AS OF 20Z...THIS WINDOW DOES APPEAR TO
BE OPENING FURTHER AS THE LEADING EDGE OF HEIGHT FALLS IS NOW
ADVANCING INTO ERN NM WELL IN ADVANCE OF A TIGHTLY-WOUND UPPER LOW
IN CENTRAL AZ. VISIBLE SATELLITE CONFIRMS THIS TREND AS BOUNDARY
LAYER CUMULUS AND MID-LEVEL CLOUDS HAVE QUICKLY THICKENED BETWEEN
CLINES CORNERS AND CLOVIS. SURFACE OBSERVATIONS CLEARLY REVEAL THE
DRYLINE WILL NOT MIX AS FAR EAST AS 12Z MODELS AND RECENT RUNS OF
THE HRRR SUGGESTED...LARGELY DUE TO A SLOWER UPPER TROUGH AND ITS
SUBSEQUENT DELAY WITH WESTERLY SURFACE FLOW. SURFACE FRONT FROM
EARLIER THIS MORNING HAS ESSENTIALLY DIFFUSED...ALTHOUGH MODELS
INDICATE SOME SEMBLANCE OF THIS A FEW THOUSAND FEET ALOFT LIFTING
SLOWLY NORTH AS A WARM FRONT. LATEST RUC APPEARS THE MOST CREDIBLE
WITH THE DRYLINE SHARPENING UP NEAR HWY 385 BEFORE SUNSET INSTEAD OF
I27 AS PREVIOUSLY THOUGHT. EXODUS OF A SUBTROPICAL CIRRUS SHIELD
ACROSS THE NWRN HALF OF THE CWA HAS ALREADY PUSHED CIN TO NEAR ZERO
IN PLACES...WITH HIGH-BASED CUMULONIMBUS FOUND DEVELOPING FROM NEAR
TCC NORTHEAST TO NEAR CHANNING...AND ALSO SOUTHWARD INTO OUR WRN
COUNTIES. CAPE INCREASES MARKEDLY FARTHER EAST WHERE MOISTURE IS
SIGNIFICANTLY BETTER...SO TEND TO BELIEVE A LARGE HAIL THREAT WILL
DOMINATE AS STORMS FAVOR DISCRETE MODES...LIKELY SUPERCELLULAR
GIVEN FAVORABLE BOUNDARY-ORIENTED 0-6KM SHEAR VECTORS. RECENT SWOMCD
FULLY CONFIRMS THREAT FOR SVR CONVECTION.
AS EARLIER AFD MENTIONED...THE GREATEST COVERAGE OF CONVECTION
SHOULD TAKE AIM NORTH OF THE CWA GENERALLY ALONG AND NORTH OF THE
AXIS OF A CYCLONICALLY-CURVED UPPER JET STREAK. WILL HOWEVER
MAINTAIN ISO TSTRM MENTION MAINLY OVER OUR NRN COUNTIES THROUGH
MIDNIGHT AS THIS REGION WILL LIE NEAR THE EDGE OF DEEP ASCENT.
DRYLINE SHOULD BE OVERTAKEN BY A PACIFIC COLD FRONT BEFORE SUNRISE
FRI AT WHICH POINT BREEZY WESTERLY WINDS WILL DEVELOP...WITH DEEPER
MIXING BY MID-MORNING LIKELY SECURING SUSTAINED WLY WINDS OF 20-25
MPH. DEPARTURE OF THE UPPER TROUGH FROM SERN CO INTO NEBRASKA BY 18Z
IMPLIES A DIMINISHED GRADIENT FLOW LOCALLY...SO DESPITE MORE
UNSEASONABLE WARMTH...FIRE WEATHER CONCERNS DO NOT APPEAR ROBUST
ENOUGH FOR A FIRE WEATHER WATCH AS WINDS WILL BE DIMINISHING
THROUGHOUT THE DAY.
LONG TERM...
ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY...WITH A
PERIOD OF UNSETTLED WEATHER POSSIBLE FROM THE LATTER HALF OF THE
WEEKEND INTO AT LEAST EARLY NEXT WEEK.
THE MID-LEVEL PATTERN THROUGH MUCH OF THE EXTENDED WILL BE DOMINATED
BY SOME SEMBLANCE OF WESTERN TROUGHING...WHICH WILL KEEP WEST TEXAS
UNDER VARIATIONS OF SOUTHWEST FLOW ALOFT. EARLY ON...A SHORTWAVE
TROUGH WILL QUICKLY LIFT NORTHWARD ACROSS THE UPPER MIDWEST AS A
CLOSED LOW MIGRATES FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH
PLAINS FROM FRIDAY INTO SATURDAY. THIS SHOULD HELP FORCE A COLD
FRONT SOUTHWARD INTO THE SOUTH PLAINS ON SATURDAY BEFORE IT STALLS
OUT LATER IN THE DAY. THE INITIAL FROPA STILL APPEARS TO BE A DRY
ONE...WITH THE BETTER LOW-LEVEL MOISTURE SHUNTED SOUTH AND EAST OF
THE AREA. HOWEVER...BY SATURDAY NIGHT...A SOUTHERLY LLJ WILL
INCREASE AND BEGIN TO DRAW BETTER AMOUNTS OF MOISTURE UP AND OVER
THE COOL DOME IN PLACE...AND THIS WAA REGIME WILL RESULT IMPROVING
CHANCES OF ELEVATED SHOWERS/STORMS. LATEST INDICATIONS ARE THAT
THE FRONT WILL GRADUALLY RETREAT NORTHWARD SATURDAY NIGHT AND
EARLY SUNDAY...WITH PERHAPS A MCS DEVELOPING TO ITS NORTH. RIGHT
NOW...IT APPEARS THE MOST FAVORED REGION FOR A POTENTIAL MCS WOULD
BE DISPLACED TO THE NORTH...ACROSS THE PANHANDLES...THOUGH THIS
COULD CHANGE DEPENDING ON THE EXACT POSITION OF THE FRONT. FOR
NOW...HAVE CURTAILED POPS TO FAVOR THE NORTHERN AND NORTHEASTERN
SECTIONS SATURDAY NIGHT AND EARLY SUNDAY...WITH MORE DEVELOPMENT
POSSIBLE ALONG THE DRYLINE /LIKELY LOCATED NEAR THE TX/NM LINE/ BY
LATER IN THE DAY SUNDAY. THE 12Z NAM DOES ATTEMPT TO FORCE THE
FRONT BACK SOUTHWARD LATER SUNDAY...LIKELY AS A RESULT OF A
REINFORCED COLD POOL FROM THE EARLY DAY MCS...BUT THESE DETAILS
REMAIN TOO ELUSIVE/UNCERTAIN TO FOLLOW ATTM. TEMPERATURES DO ALSO
REMAIN A LITTLE TRICKY THIS WEEKEND GIVEN SOME UNCERTAINTY WITH
THE FRONTAL POSITION...BUT HAVE TENDED TOWARD A COMPROMISE FOR
NOW...WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S.
EARLY NEXT WEEK WILL FEATURE A DRYLINE ROAMING THE AREA UNDERNEATH
SOUTHWEST FLOW ALOFT AND THIS PATTERN WILL KEEP AT LEAST LOW THUNDER
CHANCES IN THE FORECAST...FAVORING THE AFTERNOON AND EVENING HOURS.
TOWARD THE MIDDLE OF NEXT WEEK THE MID-LEVEL FLOW MAY TURN MORE
WESTERLY /AND MAYBE EVEN WEAKLY ANTICYCLONIC/ AND THIS WOULD TEND TO
PUSH THE BETTER MOISTURE EASTWARD AND MAKE LOW THUNDER CHANCES EVEN
LESS CERTAIN. THUS...HAVE MAINTAINED A DRY FORECAST FROM WEDNESDAY
ONWARD FOR NOW. TEMPERATURES FOR NEXT WEEK WILL AGAIN BE ON THE WARM
SIDE OF AVERAGE...WITH HIGHS GENERALLY IN THE 80S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 52 82 47 75 49 / 10 0 10 10 20
TULIA 55 85 49 75 52 / 10 0 10 10 30
PLAINVIEW 56 85 51 76 55 / 10 0 10 10 20
LEVELLAND 54 86 53 80 57 / 10 0 10 10 20
LUBBOCK 60 88 55 80 58 / 10 0 10 10 20
DENVER CITY 54 86 53 83 55 / 10 0 0 10 20
BROWNFIELD 55 88 54 82 60 / 10 0 10 10 20
CHILDRESS 63 93 56 80 59 / 10 10 10 10 30
SPUR 61 91 56 81 61 / 10 0 10 10 20
ASPERMONT 67 96 59 84 61 / 10 0 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
655 PM CDT SAT APR 28 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY
315 PM CDT SAT APR 28 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SUNDAY AFTERNOON
INTO MONDAY...THEN TEMPERATURES AND PRECIPITATION CHANCES TUESDAY.
LATEST MOSAIC RADAR INDICATING FRONTOGENETICAL BAND EXTENDING FROM
LAKE MICHIGAN TO WESTERN MINNESOTA WEAKENING AND SHRINKING...THIS
IS IN AGREEMENT WITH THE 28.18Z RUC 700-600MB FN VECTOR CONVERGENCE
WEAKENING THE FRONTOGENETICAL BAND THIS AFTERNOON INTO THIS
EVENING.
THE 28.12Z GFS/NAM ARE IN PRETTY GOOD AGREEMENT IN LIFTING UPPER
LEVEL LOW OVER THE NORTHERN PLAINS NORTHWARD INTO CANADA SUNDAY
NIGHT AND DEVELOPING SOUTHWESTERLY FLOW ALOFT MONDAY NIGHT INTO
TUESDAY. DPROG/DT OF THE 28.12Z GFS AND NAM SHOW SHORTWAVE TROUGH
WRAPPING AROUND THE UPPER LEVEL LOW INTO THE AREA FASTER THE LAST
SEVERAL RUNS. CONFIDENCE IS INCREASING PRECIPITATION WILL
OVERSPREAD THE REGION SUNDAY AFTERNOON. NO SIGNIFICANT DIFFERENCES
NOTED BETWEEN THE 28.12Z DETERMINISTIC MODELS.
TONIGHT INTO MONDAY...FRONTOGENETICAL BAND OVER OVER WESTERN
AND CENTRAL WISCONSIN WILL CONTINUE TO WEAKEN THIS EVENING. THEN...
WEAK RIDGE BUILDS INTO EASTERN WISCONSIN AFTER MIDNIGHT TONIGHT
INTO SUNDAY MORNING. DRY WEATHER CONDITIONS ARE EXPECTED AFTER 06Z
TO AROUND 18Z SUNDAY. THE 28.12Z GFS/NAM/ECMWF ARE MORE PROGRESSIVE
WITH SHORTWAVE ROTATING AROUND UPPER LEVEL LOW INTO THE FORECAST
AREA. THE 28.12Z GFS/NAM SHOW DECENT ISENTROPIC LIFT AT 305K
SURFACE...MOISTURE TRANSPORT AND CONVERGENCE AT 925-850MB LAYER...
IN ASSOCIATION WITH THE SHORTWAVE TROUGH. HAVE INCREASED
PRECIPITATION CHANCES FROM 18Z SUNDAY TO 12Z MONDAY. THE 28.12Z
GFS/NAM SHOW AROUND 100 J/KG 0-6KM MOST UNSTABLE CAPE ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN...INTRODUCED ISOLATED THUNDER
ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN AFTER 18Z SUNDAY. WITH
THE MODELS INDICATING A FASTER SOLUTION WITH THE SHORTWAVE TROUGH...
EXPECT MUCH OF THE PRECIPITATION TO BE EAST OF THE FORECAST AREA BY
18Z MONDAY.
NEXT FORECAST CONCERN IS THE 28.12Z GFS/NAM DEVELOPING SOUTHWESTERLY
FLOW ALOFT OVER ROCKY MOUNTAINS AND UPPER MIDWEST MONDAY NIGHT INTO
TUESDAY. THE DETERMINISTIC MODELS ARE ADVECTING WARMER AIR INTO THE
FORECAST AREA WITH 850MB TEMPERATURES RISING TO PLUS 12 TO PLUS 15
DEGREES CELSIUS BY 00Z WEDNESDAY. HIGH TEMPERATURES TUESDAY WILL BE
MAINLY IN THE LOWER TO MIDDLE 70S...WITH THE POSSIBILITY OF 80
DEGREES OVER NORTHEAST IOWA OR SOUTHEAST MINNESOTA. THE 28.12Z
GFS/NAM DO SHOW MOISTURE TRANSPORT AND ISENTROPIC LIFT AT 305K
SURFACE...MAINLY AFTER 18Z TUESDAY ACROSS THE FORECAST AREA. THE
28.12Z GFS/NAM INDICATE DECENT 0-3KM SHEAR AND INSTABILITY DURING
THE DAY TUESDAY. HOWEVER...THE BEST LIFT AND CONVERGENCE AT THIS TIME
APPEARS TO BE NORTHWEST AND SOUTHWEST OF FORECAST AREA AND HAVE KEPT
SMALL CHANCES OF PRECIPITATION ACROSS FORECAST AREA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
315 PM CDT SAT APR 28 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES THROUGH THE
PERIOD AND UNSEASONABLY WARM TEMPERATURES THROUGH THURSDAY. THE
28.12Z GFS/GEM/ECMWF CONTINUE TO DEVELOP WEST TO SOUTHWESTERLY FLOW
ALOFT AND CONTINUE TO HAVE DIFFERENCES IN TIMING OF SHORTWAVE
TROUGHS EMBEDDED IN THE WEST TO SOUTHWESTERLY FLOW ALOFT THROUGH
THE PERIOD. CONFIDENCE IN TIMING OF THE INDIVIDUAL SHORTWAVE TROUGHS
MOVING INTO THE UPPER GREAT LAKES REGION IS LOW...HOWEVER
CONFIDENCE IS INCREASING AN ACTIVE WEATHER PATTERN WILL SET UP OVER
THE UPPER GREAT LAKES AND UPPER MIDWEST REGION MIDDLE OF NEXT WEEK.
THE DETERMINISTIC 28.12Z GFS/GEM/ECMWF SHOW WARM AIR ADVECTING INTO
THE FORECAST AREA TUESDAY NIGHT AND CONTINUING INTO THURSDAY...WITH
850MB TEMPERATURES RANGING FROM PLUS TWELVE DEGREES CELSIUS TO
PLUS FIFTEEN DEGREES CELSIUS AND THE 28.00Z GEFS INDICATING
STANDARD ANOMALIES OF 1-1.5. EXPECT TEMPERATURES TO BE
WELL ABOVE NORMAL THROUGH THE MIDDLE OF NEXT WEEK ACROSS FORECAST
AREA.
&&
.AVIATION...TONIGHT AND SUNDAY
655 PM CDT SAT APR 28 2012
AS OF 29.00Z...FRONTOGENTICAL BAND HAS WEAKENED AND CEILINGS ARE
GRADUALLY IMPROVING AS HIGH PRESSURE CENTERED OVER LAKE SUPERIOR
FUNNELS DRIER AIR ACROSS WISCONSIN. MOSTLY MVFR CONDITIONS ACROSS
THE AREA...EXCEPT FOR IFR IN NORTHERN IOWA AND SOUTHEAST
MINNESOTA.
ADDITIONAL SUBSIDENCE HAS LED TO CLEARING SKIES ALONG A LINE FROM
KPDC TO KMDW...AND THE NEAR-TERM CHALLENGE IS WHETHER THIS
CLEARING WILL CONTINUE TO ERODE AND REACH KRST. CURRENT THINKING
IS THAT AFTER SUNSET...ANY CLEARING AREAS WILL BEGIN TO FILL
IN...BUT DID INCLUDE PERIOD WHERE CEILINGS MAY BRIEFLY RISE TO
MVFR.
EVENTUALLY SUFFICIENT DRIER WILL WORK ITS WAY TO BOTH TAF
SITES...AND CEILINGS WILL IMPROVE TO VFR OVERNIGHT. FOR SUNDAY
MORNING...PLAN ON MID TO HIGH LEVEL CLOUDS AHEAD OF THE NEXT
SHORTWAVE. PRECIPITATION WILL DEVELOP LATE IN THE AFTERNOON AND CEILINGS
LOOK TO DROP DOWN TO MVFR AT KRST WITH RAIN SHOWERS. AT THIS TIME...DID
NOT INCLUDE THUNDER AS BEST INSTABILITY REMAINS SOUTH OF THE
SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 PM CDT SAT APR 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
338 PM CDT FRI APR 27 2012
.SHORT TERM...TONIGHT THROUGH MONDAY
338 PM CDT FRI APR 27 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION TYPE TONIGHT...THEN
PRECIPITATION CHANCES SUNDAY NIGHT INTO MONDAY.
LATEST WATER VAPOR SATELLITE IMAGERY INDICATING A COUPLE OF UPPER
LEVEL LOWS OVER THE NORTHERN ROCKIES AND THE CENTRAL HIGH PLAINS.
LATEST 19Z SURFACE ANALYSIS SHOWS LOW PRESSURE OVER WESTERN KANSAS
AND LATEST MOSAIC RADAR INDICATING SHOWERS AND THUNDERSTORMS WRAPPING
AROUND THE SURFACE LOW INTO PORTIONS OF SOUTH DAKOTA...NEBRASKA...
EASTERN KANSAS AND MISSOURI.
THE 27.12Z GFS/NAM ARE IN DECENT AGREEMENT IN LIFTING LOW PRESSURE
SYSTEM INTO THE UPPER MIDWEST AND GREAT LAKES REGION TONIGHT INTO
SATURDAY. THE DPROG/DT OF THE NAM/GFS DOES SHOW SURFACE/UPPER LEVEL
LOW A SLOWER PROGRESSION NORTHEASTWARD INTO THE GREAT LAKES REGION.
PLUS...WITH DRY AIRMASS IN PLACE OVER AREA PER 27.12Z UPPER AIR
SOUNDINGS. THIS WILL HAVE IMPACTS ON PRECIPITATION TIMING INTO THE
FORECAST AREA THIS EVENING. HAVE SLOWED BEGIN TIME AND REDUCED
PRECIPITATION CHANCES FROM WEST TO EAST ACROSS FORECAST AREA THIS
EVENING. THE DETERMINISTIC 27.12Z GFS/NAM INDICATE DECENT
ISENTROPIC LIFT AT 300K SURFACE AND DEEP QG FORCING IN
ASSOCIATION WITH SURFACE LOW MOVING INTO THE FORECAST AREA AFTER 06Z
SATURDAY. DEPENDING ON SATURATION OF ATMOSPHERE COLUMN...
PRECIPITATION WILL OVERSPREAD MUCH OF THE FORECAST AREA BY 06Z
SATURDAY. THE 27.15Z RUC AND 27.12Z NAM TIGHTEN PRESSURE GRADIENT
OUT AHEAD OF SURFACE LOW THIS EVENING OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. BOTH THE NAM AND RUC BUFKIT SOUNDINGS SHOW 25 TO
30 KNOTS MEAN ABSOLUTE MOMENTUM TRANSFER AT RST AND MCW. THE
WIND PRONE AREAS OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA WILL
APPROACH SUSTAINED WIND SPEEDS OF 30 MPH AND WILL ISSUE A WIND
ADVISORY FOR THIS AREA THROUGH 03Z SATURDAY. NEXT CONCERN IS
POTENTIAL SNOW MIXING IN WITH THE RAIN AFTER 06Z SATURDAY. THE 27.12Z
GFS/NAM BUFKIT SOUNDINGS ARE STILL INDICATING ATMOSPHERE COLUMN NEAR
OR AT ZERO DEGREES CELSIUS OVER PORTIONS OF THE FORECAST AREA FROM
09Z TO 12Z SATURDAY. FOR NOW WILL CONTINUE MENTION OF RAIN/SNOW MIX
OVER MUCH OF THE FORECAST AREA FROM 09Z TO 15Z SATURDAY.
SURFACE LOW PUSHES EAST OF FORECAST AREA SUNDAY AND SURFACE RIDGE
OVER SOUTHERN ONTARIO BUILDS SOUTH INTO THE GREAT LAKES REGION.
PARTLY TO MOSTLY SUNNY SKIES...DRY WEATHER CONDITIONS AND NEAR
NORMAL TEMPERATURES CAN BE EXPECTED ACROSS THE FORECAST AREA.
FOCUS THEN TURNS TO SUNDAY NIGHT AND MONDAY...AS SURFACE RIDGE BUILDS
INTO THE NORTHEASTERN UNITED STATES. THE 27.12Z GFS/ECMWF/GEM SHOW
SOUTHERLY FLOW MOISTURE RETURN INTO THE FORECAST AREA...IN
ASSOCIATION WITH A WEAK LOW PRESSURE SYSTEM MOVING INTO THE CENTRAL
PLAINS. THE 27.12Z NAM IS MUCH FARTHER SOUTH THAN THE GFS/ECMWF/GEM
AND THE 27.12Z GFS/ECMWF/GEM INDICATE DECENT MOISTURE TRANSPORT AND
CONVERGENCE INTO THE FORECAST AREA AFTER 00Z MONDAY. CONFIDENCE IS
INCREASING ON PRECIPITATION CHANCES AND HAVE INCREASED
PRECIPITATION CHANCES MAINLY ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA. THE 27.12Z GFS SHOWS 100-200 J/KG OF 0-6KM MOST
UNSTABLE CAPE BETWEEN 00-12Z MONDAY MAINLY OVER SOUTHERN HALF OF
FORECAST AREA. AT THIS TIME...LEFT OUT ANY MENTION OF
THUNDERSTORMS...HOWEVER CANNOT RULE OUT AN ISOLATED THUNDERSTORM
SUNDAY NIGHT INTO MONDAY MORNING.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
338 PM CDT FRI APR 27 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES THROUGH THE
FORECAST PERIOD. ALL THE DETERMINISTIC 27.12Z GFS/GEM/ECMWF ARE IN
GOOD AGREEMENT IN DEVELOPING WEST TO SOUTHWEST FLOW ALOFT THROUGH THE
PERIOD. MAIN DIFFERENCES BETWEEN THE MODELS IS TIMING THE EMBEDDED
SHORTWAVE TROUGHS IN THE WEST-SOUTHWESTERLY FLOW ALOFT INTO THE UPPER
GREAT LAKES REGION. CONFIDENCE IN TIMING OF SHORTWAVE TROUGHS INTO
THE REGION IS LOW...WILL CONTINUE WITH PRECIPITATION CHANCES
THROUGH THURSDAY. ALL THE DETERMINISTIC MODELS ARE IN DECENT
AGREEMENT ADVECTING LOW LEVEL WARM AIR INTO THE AREA MIDDLE OF NEXT
WEEK AND ALLOW FOR ABOVE NORMAL TEMPERATURES TUESDAY INTO THURSDAY.
&&
.AVIATION...
1130 AM CDT FRI APR 27 2012
CLOUDS WILL BE ON THE INCREASE TONIGHT...WITH LOWERING CIGS BETWEEN
09-12Z. -RA WILL FOLLOW WITH THE LIKELY MVFR/IFR CIGS...AND PROBABLY
SOME VSBY RESTRICTIONS. COLD AIR A LOFT COULD RESULT IN SOME -SN
MIXING IN WITH THE -RA BETWEEN 09-15Z...PER LATEST SOUNDINGS. BETTER
CHANCES AT KRST...AND WILL ADD SOME -RASN MIX OVERNIGHT. DON/T
EXPECT ANY -SN ACCUMULATIONS THOUGH. IF IT CHANGES OVER TO ALL SNOW
FOR A SHORT PERIOD...VSBYS WILL LIKELY BE REDUCED TO 2SM.
PCPN WILL LINGER THROUGH MUCH OF SAT AS AN UPPER LEVEL SHORTWAVE
TROUGH SPINS ACROSS THE REGION...AND EXPECT A CONTINUATION OF THE
MVFR/IFR CONDITIONS THROUGH THE DAY. PCPN SHOULD DIMINISH AFTER 00Z
AS THE SHORTWAVE EXITS AND HIGH PRESSURE FROM THE NORTHEAST EXERTS
SOME INFLUENCE. THE LOW CIGS COULD HANG ON MOST OF THE
NIGHT...ESPECIALLY FOR KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
338 PM CDT FRI APR 27 2012
WI...NONE.
MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ086-087-094-
095.
IA...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR IAZ008>010-018-
019-029-030.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE
LOW WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE
AREA. DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST
WISCONSIN...THUS AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST
TO SATURATE. OF CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT.
SOUNDINGS FROM BOTH THE GFS AND NAM INDICATE THE POTENTIAL FOR THE
COLUMN TO COOL ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS
NORTH OF INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH
ICE WILL BE PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS
INDICATE TO BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH
SURFACE TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY
SNOW THAT DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE
RAIN COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC
RAIN CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR
OUT AND THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE
ON THE UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY
THROUGH THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO
THE REGION.
&&
.AVIATION...
1130 AM CDT FRI APR 27 2012
CLOUDS WILL BE ON THE INCREASE TONIGHT...WITH LOWERING CIGS BETWEEN
09-12Z. -RA WILL FOLLOW WITH THE LIKELY MVFR/IFR CIGS...AND PROBABLY
SOME VSBY RESTRICTIONS. COLD AIR A LOFT COULD RESULT IN SOME -SN
MIXING IN WITH THE -RA BETWEEN 09-15Z...PER LATEST SOUNDINGS. BETTER
CHANCES AT KRST...AND WILL ADD SOME -RASN MIX OVERNIGHT. DON/T
EXPECT ANY -SN ACCUMULATIONS THOUGH. IF IT CHANGES OVER TO ALL SNOW
FOR A SHORT PERIOD...VSBYS WILL LIKELY BE REDUCED TO 2SM.
PCPN WILL LINGER THROUGH MUCH OF SAT AS AN UPPER LEVEL SHORTWAVE
TROUGH SPINS ACROSS THE REGION...AND EXPECT A CONTINUATION OF THE
MVFR/IFR CONDITIONS THROUGH THE DAY. PCPN SHOULD DIMINISH AFTER 00Z
AS THE SHORTWAVE EXITS AND HIGH PRESSURE FROM THE NORTHEAST EXERTS
SOME INFLUENCE. THE LOW CIGS COULD HANG ON MOST OF THE
NIGHT...ESPECIALLY FOR KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
740 AM CDT FRI APR 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM....RABERDING
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
741 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE LOW
WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE AREA.
DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST WISCONSIN...THUS
AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST TO SATURATE. OF
CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT. SOUNDINGS FROM BOTH
THE GFS AND NAM INDICATE THE POTENTIAL FOR THE COLUMN TO COOL
ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS NORTH OF
INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH ICE WILL BE
PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS INDICATE TO
BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH SURFACE
TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY SNOW THAT
DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE RAIN
COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC RAIN
CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR OUT AND
THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE ON THE
UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY THROUGH
THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO THE
REGION.
&&
.AVIATION...TODAY AND TONIGHT
618 AM CDT FRI APR 27 2012
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CENTRAL PLAINS AND INTO
SOUTHERN IOWA TONIGHT. LOOK FOR SHOWERS TO MOVE OVER KRST LATE
THIS AFTERNOON...WITH THE SHOWERS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS EVENING AND IMPACTING KLSE. PLAN ON CEILINGS
IN THE 8 TO 10 KFT RANGE AT THE TAF SITES THROUGH MUCH OF THE DAY
AS THE LOW APPROACHES THE REGION. CEILINGS WILL THEN LOWER INTO
THE MVFR CATEGORY AFTER MIDNIGHT TONIGHT WITH CLOUD BASES IN THE
1500 TO 2000 FT RANGE. LOOK FOR SOUTHEAST WINDS TO INCREASE INTO
THE 10 TO 17 KT RANGE TODAY WITH GUSTS AROUND 24 KTS POSSIBLE. THE
WINDS WILL BECOME EASTERLY TONIGHT AS THE LOW EDGES CLOSER.
FORECAST SOUNDINGS SUGGEST CEILINGS MAY LOWER INTO THE IFR
CATEGORY LATE TONIGHT INTO EARLY SATURDAY MORNING. DRY EASTERLY
FLOW NEAR THE SURFACE SHOULD KEEP CEILINGS IN THE MVFR CATEGORY
BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. ALSO...THE RAIN MAY
MIX WITH OR CHANGE OVER TO SNOW AT TIMES TONIGHT INTO EARLY
SATURDAY MORNING. IF SNOW IMPACTS THE TAF SITES...VISIBILITIES
COULD BE REDUCED TO AROUND 2 MILES. WITH SURFACE TEMPERATURES WELL
ABOVE FREEZING...LITTLE OR NOW SNOW ACCUMULATION IS EXPECTED.
CONFIDENCE LOW ON PRECIPITATION SWITCHING OVER TO ALL SNOW SO HAVE
NOT INCLUDED IT IN THE FORECAST AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
740 AM CDT FRI APR 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE LOW
WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE AREA.
DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST WISCONSIN...THUS
AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST TO SATURATE. OF
CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT. SOUNDINGS FROM BOTH
THE GFS AND NAM INDICATE THE POTENTIAL FOR THE COLUMN TO COOL
ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS NORTH OF
INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH ICE WILL BE
PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS INDICATE TO
BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH SURFACE
TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY SNOW THAT
DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE RAIN
COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC RAIN
CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR OUT AND
THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE ON THE
UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY THROUGH
THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO THE
REGION.
&&
.AVIATION...TODAY AND TONIGHT
618 AM CDT FRI APR 27 2012
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CENTRAL PLAINS AND INTO
SOUTHERN IOWA TONIGHT. LOOK FOR SHOWERS TO MOVE OVER KRST LATE
THIS AFTERNOON...WITH THE SHOWERS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS EVENING AND IMPACTING KLSE. PLAN ON CEILINGS
IN THE 8 TO 10 KFT RANGE AT THE TAF SITES THROUGH MUCH OF THE DAY
AS THE LOW APPROACHES THE REGION. CEILINGS WILL THEN LOWER INTO
THE MVFR CATEGORY AFTER MIDNIGHT TONIGHT WITH CLOUD BASES IN THE
1500 TO 2000 FT RANGE. LOOK FOR SOUTHEAST WINDS TO INCREASE INTO
THE 10 TO 17 KT RANGE TODAY WITH GUSTS AROUND 24 KTS POSSIBLE. THE
WINDS WILL BECOME EASTERLY TONIGHT AS THE LOW EDGES CLOSER.
FORECAST SOUNDINGS SUGGEST CEILINGS MAY LOWER INTO THE IFR
CATEGORY LATE TONIGHT INTO EARLY SATURDAY MORNING. DRY EASTERLY
FLOW NEAR THE SURFACE SHOULD KEEP CEILINGS IN THE MVFR CATEGORY
BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. ALSO...THE RAIN MAY
MIX WITH OR CHANGE OVER TO SNOW AT TIMES TONIGHT INTO EARLY
SATURDAY MORNING. IF SNOW IMPACTS THE TAF SITES...VISIBILITIES
COULD BE REDUCED TO AROUND 2 MILES. WITH SURFACE TEMPERATURES WELL
ABOVE FREEZING...LITTLE OR NOW SNOW ACCUMULATION IS EXPECTED.
CONFIDENCE LOW ON PRECIPITATION SWITCHING OVER TO ALL SNOW SO HAVE
NOT INCLUDED IT IN THE FORECAST AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CDT FRI APR 27 2012
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ032-033-041-
053>055-061.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE LOW
WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE AREA.
DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST WISCONSIN...THUS
AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST TO SATURATE. OF
CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT. SOUNDINGS FROM BOTH
THE GFS AND NAM INDICATE THE POTENTIAL FOR THE COLUMN TO COOL
ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS NORTH OF
INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH ICE WILL BE
PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS INDICATE TO
BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH SURFACE
TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY SNOW THAT
DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE RAIN
COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC RAIN
CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR OUT AND
THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE ON THE
UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY THROUGH
THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO THE
REGION.
&&
.AVIATION...THROUGH 06Z SATURDAY
1143 PM CDT THU APR 26 2012
A GRADUAL THICKENING AND LOWERING OF THE CLOUDS IS EXPECTED TO
OCCUR THROUGH FRIDAY AS A DEVELOPING STORM SYSTEM OVER COLORADO
STARTS TO ADVANCE TOWARD THE AREA. LOOK FOR VFR CONDITIONS TO
PREVAIL THROUGH FRIDAY WITH CEILINGS REMAINING AT OR ABOVE 10
THOUSAND FEET. THE GRADIENT BETWEEN THE APPROACHING AREA OF LOW
PRESSURE AND DEPARTING SURFACE HIGH WILL CREATE GUSTS OF 20 TO 25
KNOTS OUT OF THE SOUTHEAST AT BOTH SITES FROM MID TO LATE MORNING
THROUGH THE AFTERNOON. AFTER 00Z SATURDAY...A BAND OF
FRONTOGENESIS IN THE 850-500 MB LAYER WILL SET UP ACROSS THE AREA.
THE FORCING FROM THIS WILL BE AIDED BY 2 TO 5 UBAR/S OF UP GLIDE
ON THE 300K ISENTROPIC SURFACE. THIS FORCING IS EXPECTED TO BE
ENOUGH TO ALLOW SATURATION TO OCCUR AND FOR LIGHT RAIN TO DEVELOP.
INITIALLY NOT EXPECTING THE RAIN TO REDUCE THE VISIBILITY BUT THIS
WILL BE POSSIBLE AFTER 06Z SATURDAY AS WILL MVFR CEILINGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CDT FRI APR 27 2012
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ032-033-041-
053>055-061.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS MIAMI FL
1253 AM EDT SUN APR 29 2012
.AVIATION...SURFACE TROUGH OF LOW PRESSURE CONTINUES TO MOVES VERY
SLOWLY WEST ACROSS SOUTHEAST FLORIDA WHILE A MID LEVEL LOW IS
CENTERED JUST OFF NORTHWEST CUBA. THESE FEATURES WILL TRANSPORT
CONSIDERABLE AMOUNTS OF MOISTURE INTO THE LOCAL AREA THROUGH THE
TAF PERIOD. VCSH IS WARRANTED FOR ALL TAF SITES, ALTHOUGH
PREVAILING RA WITH MVFR CEILINGS MAY BE ASSIGNED FOR A FEW
TERMINALS. A FEW TSRA ARE ALSO EXPECTED, BUT ANTICIPATED COVERAGE
TOO LOW TO INCLUDE VCTS ATTM. CEILINGS AND VISIBILITIES WILL
OCCASIONALLY BE REDUCED AND RESULT IN MVFR-IFR CONDITIONS. EAST
WINDS WILL AVERAGE 10 TO 15 KNOTS, WITH OCCASIONAL GUSTS TO 25
KNOTS, ESPECIALLY EAST COAST AFTER 12Z. EVEN HIGHER GUSTS ARE
POSSIBLE IN ANY HEAVIER SHRA/TSRA, MAINLY LATE IN THE FORECAST
PERIOD.
&&
.PREV DISCUSSION... /ISSUED 900 PM EDT SAT APR 28 2012/
UPDATE...CHALLENGING FORECAST FOR TONIGHT, BUT HERE GOES! RADAR
IMAGERY SHOWS A MID LEVEL LOW JUST NW OF ANDROS. THE LOCAL AREA IS
UNDER THE SUBSIDENCE SIDE OF THIS FEATURE. THIS IS RESULTING IN A
DRY EVENING BUT UNDER AN OVERCAST SKY. HOWEVER, IT STILL LOOKS AS
THOUGH THINGS COULD CHANGE QUICKLY AFTER MIDNIGHT FOR ESPECIALLY
THE SE COAST...BROWARD AND ESPECIALLY MIAMI-DADE. THE REASON
BEING A POTENT SHORTWAVE IS MOVING NORTH TOWARDS SOUTH FLORIDA
AROUND A MID LEVEL LOW JUST NORTH OF THE YUCATAN. TIMING OF THIS
SHORTWAVE IS TO THE SOUTHERN TIP OF THE FL PENINSULA BY 6 AM. DIVERGENCE
WILL INCREASE THROUGHOUT THE NIGHT OUT AHEAD OF THIS VERY
IMPRESSIVE SHORTWAVE, AND AS LOW LEVEL CONVERGENCE INCREASES
ALONG THE ATLANTIC COAST OVERNIGHT DUE TO INCREASING LOW LEVEL
FLOW, THIS COULD RESULT IN QUICK DEVELOPMENT OF SHRA/TSTORMS AFTER
MIDNIGHT. THE HRRR IS BULLISH ON REALLY DEVELOPING CONVECTION
ALONG THE ENTIRE ATLANTIC COAST AT AROUND THE MIDNIGHT TIME AND
CONTINUING THROUGH THE NIGHT. QPF FIELDS OFF BOTH THE GFS/ECMWF
SHOW A HIGH SIGNAL BETWEEN 06-12Z AS WELL...ESPECIALLY OFF THE
MIAMI-DADE COAST.
THERE COULD BE LOCALIZED HEAVY RAIN DEVELOPMENT OVERNIGHT. SHOULD
THIS OCCUR, BELIEVE THE MOST LIKELY LOCALE IS ALONG THE MIAMI-
DADE COAST...BUT CANNOT RULE OUT ANYWHERE ALONG THE ATLANTIC
COAST. DECREASED POPS SUBSTANTIALLY THROUGH MIDNIGHT, THEN HAVE
INCREASING POPS OVERNIGHT FOR THE SOUTH AND EAST COASTS...BUT KEPT
LOW POPS INLAND AND TO THE GREATER NAPLES AREA AS IT LOOKS TO STAY
MOSTLY DRY THERE OVERNIGHT.
SEE PREVIOUS DISCUSSION BELOW FOR FORECAST DETAILS BEYOND TONIGHT.
SHOULD MENTION THOUGH THAT THE LATEST 28.12Z RUN OF THE ECMWF
SHOWS LOW LEVEL WIND FIELDS INCREASING SUN NIGHT-MON...25-30 KT.
THE GFS CONTINUES STRONGER. EITHER WAY, WITH CONVECTION
AROUND...SHOWERS AND THUNDERSTORMS ESPECIALLY FROM SUNDAY NIGHT
THROUGH TUESDAY COULD BE ACCOMPANIED BY NOT ONLY TORRENTIAL RAINS
(LOCALIZED FLOODING CONCERNS ESPECIALLY ATLANTIC COAST), BUT ALSO
A GROWING CONCERN FOR SOME STRONG WIND GUSTS DUE TO CONVECTION IN
A FAST LOW LEVEL FLOW. AS FAR AS THE HEAVY RAIN RISK...IT LOOKS
AS THOUGH THIS RISK MAY CONTINUE EVEN INTO MID WEEK FOR THE EAST
COAST. HOWEVER, HIGHER THAN NORMAL UNCERTAINTY PRECLUDES ANY FLOOD
WATCH ISSUANCE AT THIS TIME. /GREGORIA
PREV DISCUSSION... /ISSUED 738 PM EDT SAT APR 28 2012/
AVIATION...FC TROF XTNDG FM UPR FLA STRAITS NE TO N BAHAMAS.
OVR NXT 24 HRS THIS TROF WL MOV SLOLY W ONTO S FLA WITH A MOIST
EASTERLY WND FLOW PERSISTING ACRS THE AREA. ALG E COAST...VCSH IN
TAFS AFT 09Z BUT WL PLC VCSH IN TAFS AFT 09Z AND AMD IF NEEDED IF
HVY PCPN ACTIVITY DVLPS. MVFR CIGS PSBL IN HVIER RA BUT VFR FOR
MOST PART. WND E 10 TO 15 KTS WITH OCNL HIR GUST BUT WND XPCTD TO
INCRS AFT 09Z WITH PSBL GUSTS > 20 KTS AFT 29/14Z. ATTM NO TSRA
IN TAFS THOUGH ISOLD TSRA PSBL THRU PD. AT KAPF...VFR THRU PD WITH
WND < 10 KTS BUT INCRG AFT 29/14Z 12-14 KTS WITH GUSTS > 20 KTS.
PREV DISCUSSION... /ISSUED 227 PM EDT SAT APR 28 2012/
DISCUSSION...THE DAY IN THE LIFE OF A FORECASTER CAN BE QUITE
TUMULTUOUS AND TODAY IS CERTAINLY NO EXCEPTION. GOING INTO THE
FIRST AND SECOND PERIODS THE MODELS ARE STILL DIVERGING ON HOW TO
HANDLE WHERE THE GREATEST CONVERGENCE AND LIFT WILL BE TO SET UP
CONVECTIVE PRECIPITATION. WATER VAPOR CONTINUES TO SHOW A PLUME OF
RICH TROPICAL MOISTURE FLOWING NORTH ALONG A MID LEVEL TROUGH AXIS
OVER THE WESTERN CARIBBEAN. RADAR SIGNATURES INDICATE THAT AT THE
SFC A CONVERGENT BOUNDARY IS SUGGESTED ALONG THE EXTREME SOUTHERN
TIP OF THE PENINSULA AND EXTENDING INTO THE BAHAMAS. SCT SHRA HAVE
DEVELOPED ALONG THIS BOUNDARY WITH ALSO ISOLD TSRA MAINLY FROM
CENTRAL BROWARD SOUTH ACROSS CENTRAL MIAMI-DADE COUNTIES AND ARE
MOVING WEST IN THE LOW LEVEL EASTERLY FLOW AROUND A SFC RIDGE THAT
STRETCHES ACROSS N FL. SO THIS CONTINUES THE THREAT FOR LATER
DEVELOPMENT ALONG THE COASTAL COLLIER COUNTY REGION THIS
AFTERNOON. BOTH THE NAM AND GFS INITIALIZED QUITE WELL DEPICTING
THIS BOUNDARY AND INTENSIFY THE TROUGH MOVING IT WEST ACROSS S FL
LATE TONIGHT AND SUNDAY THEN INTO THE SOUTHEAST GULF BY SUNDAY
NIGHT WHEREAS THE ECMWF DOES NOT SHOW THE TROUGH. AS THIS TROUGH
DEEPENS AND MOVES WEST, THE NAM DEVELOPS A BAND OF HEAVY
CONVECTION MOVING IT OVER THE SOUTHERN PORTIONS OF THE CWA WITH IN
EXCESS OF TWO INCHES OF RAINFALL BY LATE SUNDAY OVER SOUTHERN
MIAMI-DADE COUNTY WHILE THE GFS KEEPS THE HEAVIEST ACTIVITY
OFFSHORE AS DOES THE ECMWF. ALTHOUGH THE GFS DOES SHOW THE HIGHEST
RAINFALL TOTALS REMAINING OFFSHORE, IT DOES GIVE HIGHER POPS THAN
THE ECMWF WHICH SEEMS REASONABLE GIVEN ITS AGREEMENT TO THE NAM ON
THE SFC TROUGH POSITION. GIVEN ALL OF THIS, WILL LEAN MUCH CLOSER
TO THE NAM AND GFS AS IT MAKES MORE SENSE TO HAVE PLENTY OF
SHRA/TSRA MOVING ONSHORE WITH THE LOW LEVEL EAST WIND FLOW IN
PLACE.
IN ADDITION, WITH THE NAM AND GFS CONTINUING TO SHOW A DEVELOPING
SFC TROUGH THEY BOTH INCREASE THE WIND ACROSS THE LOCAL AREA ON
SUNDAY WITH SCA CONDITIONS OVER THE ATLANTIC WATERS. THIS COULD ALSO
SET UP GOOD COASTAL CONVERGENCE ALONG THE E CST LATE TONIGHT INTO
EARLY SUNDAY FOR POSSIBLE LOCALLY HEAVY RAINFALL IN SOME LOCATIONS
ESPECIALLY FROM EAST CENTRAL BROWARD AND SOUTH ALONG AND NEAR THE
COAST OF MIAMI-DADE COUNTY.
FOR THE EXTENDED, THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK WHEREAS THE ECMWF BUILDS A DEEP LAYER
RIDGE OVER THE ATLANTIC AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
MARINE...MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS
DIVERGING ON THE STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH
ACROSS S FL OVER THE REMAINDER OF WEEKEND. FOR NOW...AM LEANING
TOWARDS A GENERAL EAST WIND INCREASING ON SUNDAY TO AROUND 20
KNOTS OVER THE ATLANTIC WATERS WITH SEAS BUILDING TO POSSIBLY 6
FEET.
FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH PLENTY OF TROPICAL
MOISTURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 72 82 73 / 40 50 50 30
FORT LAUDERDALE 80 72 82 74 / 60 50 50 40
MIAMI 81 72 81 73 / 60 50 50 40
NAPLES 83 69 83 70 / 40 30 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
154 AM EDT SUN APR 29 2012
.SYNOPSIS...
A COLD FRONT WILL MEANDER ACROSS THE MIDLANDS TONIGHT THROUGH
SUNDAY. MID AND UPPER LEVEL HIGH PRESSURE RIDGE INTO THE
SOUTHEASTERN STATES WILL HOLD TEMPERATURES ABOVE NORMAL FOR MUCH
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE COLUMBIA AREA ALONG WITH
EXTENSIVE CLOUDINESS. WEAK WEDGE CONTINUES ACROSS THE NORTHERN
MIDLANDS WHERE TEMPERATURES REMAIN IN THE LOWER 60S. RUC MODEL
APPEARS TO HAVE THE BEST HANDLE ON SITUATION WITH DIFFUSE FRONT
ACROSS THE REGION OVERNIGHT AND WEAK NORTHEAST LOW-LEVEL FLOW.
CLOUDINESS WILL LIKELY REMAIN FROM CAE NORTH REDUCING FOG THREAT
IN THE MORNING. DRIER AIR IN THE AGS AREA MAY ALSO HINDER FOG
DEVELOPMENT. SREF KEEPS FOG ACROSS THE COASTAL PLAIN. ADJUSTED
WINDS/TEMPERATURE OVERNIGHT.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
THE FRONTAL BOUNDARY MEANDERING ACROSS THE CWA WILL SLOWLY MOVE
NORTHWARD SUNDAY...BUT THEN BEGIN TO DIP ONCE AGAIN SOUTHWARD
SUNDAY NIGHT INTO MONDAY AS MID/UPPER LEVEL RIDING BUILDS ACROSS
THE SOUTHEAST. THE REMNANTS OF FRONTAL BOUNDARY SHOULD FINALLY PUSH
NORTH OF THE CWA OVERNIGHT ON MONDAY NIGHT. MODELS IN GOOD
AGREEMENT THAT MID/UPPER LEVEL RIDGING WILL BUILD ACROSS THE
SOUTHEAST THROUGH THE PERIOD. THIS WILL ALLOW TEMPERATURE TO RISE
EVEN MORE ABOVE NORMAL FOR BOTH SUNDAY. TEMPERATURES WILL BE
SLIGHTLY COOLER ESPECIALLY ACROSS THE NORTHERN CWA AS FRONTAL
BOUNDARY SLIPS BACK SOUTHWARD LATE SUNDAY INTO SUNDAY NIGHT.
TEMPERATURES WILL APPROACH 90 DEGREES IN SOME LOCATIONS SUNDAY.
MODELS AND ENSEMBLES NOT VERY CONFIDENT ON CHANCES FOR RAINFALL
WITH BOUNDARY IN THE VICINITY. MOST POPS REMAIN BELOW 15 PERCENT
THROUGH THE PERIOD. AS FOR LOW TEMPERATURES THROUGH THE
PERIOD...GUIDANCE AND LOCAL NUMBERS REASONABLY CLOSE AND WILL STAY
NEAR CONSENSUS THROUGH THE PERIOD.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
THE LONG TERM PERIOD WILL BEGIN WITH MID/UPPER LEVEL RIDGING
ACROSS THE SOUTHEAST ON TUESDAY. THIS WILL CONTINUE THROUGH
THURSDAY...WITH A GRADUAL WEAKENING OF THE RIDGE OVER THE REGION
AS IT BEGINS TO SHIFT WESTWARD TOWARD TEXAS BY FRIDAY/SATURDAY. AT
THE SURFACE...HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL RIDGE
INTO SOUTH CAROLINA AND GEORGIA THROUGH THURSDAY. RIDGING ACROSS
THE AREA WILL ALLOW TEMPERATURES TO REMAIN WELL ABOVE NORMAL
THROUGH THE PERIOD. EXPECT MIDDLE TO UPPER 80S...MAYBE EVEN A FEW
TEMPERATURES AROUND 90 THROUGH THE PERIOD. BY FRIDAY AND
SATURDAY...H5 HEIGHTS BEGIN TO LOWER ACROSS THE REGION AND HIGH
PRESSURE SETTLES FARTHER SOUTH AND EAST. BOTH ECMWF/GFS INDICATE A
WEAK FRONT MOVING ACROSS THE AREA FRIDAY NIGHT. THIS WILL ALLOW
FOR SOME SLIGHTLY COOLER TEMPERATURES FOR THE END OF THE EXTENDED
PERIOD. MUCH OF THE EXTENDED PERIOD LOOKS DRY. BUT CANNOT RULE OUT
AN ISOLATED AFTERNOON SHOWER OR STORM THROUGH THE ENTIRE WEEK.
HAVE INCLUDED A SLIGHT CHANCE FOR A SHRA/TSRA FRIDAY/FRIDAY NIGHT
FOR THE NORTHWEST PORTION OF THE CWA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
MVFR TO IFR CONDITIONS THROUGH MID MORNING...THEN IMPROVING TO
VFR. FOG HAS ALREADY BEGUN TO DEVELOP ACROSS THE REGION WITH MVFR
CIGS OVER AND NORTHWEST OF CAE/CUB. EXPECT THE FOG TO EXPAND
THROUGH DAYBREAK WITH LESS EXPANSION OF THE LOW CLOUDS. HAVE
LOWERED VSBYS AT ALL TAF SITES BETWEEN 08Z AND 13Z DUE TO CURRENT
OBSERVATION TRENDS. FOG WILL ERODE WITH SUNRISE AND
MIXING...HOWEVER EXPECT 14Z TO BE THE TARGET FOR EROSION OF ALL
FOG. SOME CUMULUS WILL DEVELOP DURING THE LATE MORNING AND
AFTERNOON WITH DISSIPATION OF CLOUDS AT SUNSET. FOG WILL AGAIN BE
POSSIBLE AFTER 30/06Z...HOWEVER CONFIDENCE IN TIMING AND COVERAGE
IS TOO LOW TO INCLUDE ATTM.
EXTENDED AVIATION OUTLOOK MONDAY THROUGH THURSDAY...NO SIGNIFICANT
IMPACTS TO AVIATION EXPECTED MONDAY THROUGH THURSDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
314 AM CDT SUN APR 29 2012
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 310 AM CDT SUN APR 29 2012
AN UPPER LEVEL LOW OVER THE DAKOTAS WILL PUSH NORTH INTO CANADA
WHILE THE BASE OF THE ASSOCIATED UPPER TROUGH PUSHES INTO THE
CENTRAL PLAINS. FIRST A RIGHT REAR QUAD OF AN UPPER JET MOVES ACROSS
SOUTHWEST KANSAS THIS MORNING. ANOTHER JET MOVES ACROSS ARIZONA INTO
THE TEXAS PANHANDLE THIS EVENING PUTTING THE LEFT FRONT QUAD ACROSS
FAR SOUTHWEST AND SOUTH CENTRAL KANSAS. ENHANCED LIFT ASSOCIATED
WITH THESE UPPER LEVEL FEATURES WILL ALLOW FOR MOISTURE TO BE
TRANSPORTED NORTHWARD INTO MUCH OF THE FA WITH WARM AIR ADVECTION
AND ISENTROPIC LIFT OVER THE COLD FRONT DRAPED ACROSS OKLAHOMA AND
THE TEXAS PANHANDLE. SHOWERS AND ISOLATED THUNDERSTORMS WILL
INCREASE THIS MORNING INTO THE AFTERNOON WITH SOME POSSIBLE SEVERE
THUNDERSTORMS AND HEAVY RAINFALL IN THE FAR SOUTHEAST AROUND
MEDICINE LODGE. WILL HAVE TO MONITOR FOR POSSIBLE FLOODING IN THE
SOUTHEAST FA WITH CONTINUED TRAINING OF THUNDERSTORMS WITH PRECIPITABLE
WATER OVER AN INCH INTO THE AFTERNOON AND EVENING. AS YOU GO
NORTH LIGHTER QPF AMOUNTS ARE FORECAST WITH LESS THAN ONE TENTH IN
THE FAR NORTH. POPS WILL RANGE FROM AROUND 40 FAR NORTH TO NEAR
100 PERCENT IN THE SOUTHEAST. COULD ALSO HAVE SOME HAIL UP TO
QUARTER SIZE IN THE SOUTHEAST FA WITH THE BEST INSTABILITY. CAPE
FIELDS INCREASE TO 1000 TO 1500 J/KG BY LATE AFTERNOON INTO THE
OVERNIGHT AS MORE MOISTURE MOVES INTO WESTERN KANSAS WITH A
CONTINUATION OF THUNDERSTORMS THROUGH THE NIGHT ESPECIALLY IN THE
SOUTHEAST FA WITH THE BEST JET DYNAMICS.
HIGHS TODAY ARE EXPECTED TO BE ONLY IN THE MID TO UPPER 60S WITH
LITTLE OR NO INSOLATION. OVERNIGHT LOWS WILL BE IN THE LOW TO MID
50S WITH AROUND 60 SOUTHEAST FA.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 258 AM CDT SUN APR 29 2012
AN UPPER LEVEL LONG WAVE TROUGH WILL BE FOUND ACROSS THE ROCKIES AS
THE LONG TERM PERIOD BEGINS WITH A SERIES OF WEAK SHORTWAVES MOVING
ACROSS THE CENTRAL PLAINS. A JET STREAK WILL BE EXITING THE CENTRAL
PLAINS ON MONDAY AND PLACE SOUTHWEST KANSAS IN THE RIGHT ENTRANCE
REGION. THIS WILL ENHANCE LIFT ACROSS OUR AREA. A WEAK SURFACE LOW
WILL BE FOUND ACROSS FAR WESTERN KANSAS IN THE MORNING WITH A
FRONTAL BOUNDARY EXTENDING EASTWARD ACROSS CENTRAL KANSAS. WINDS
WILL GENERALLY BE FROM THE SOUTH SOUTHEAST WHICH WILL CONTINUE TO
BRING AMPLE MOISTURE TO THE AREA. A DRYLINE WILL BE FOUND ACROSS THE
KS/CO BORDER IN THE MORNING THEN SHIFT EASTWARD AS THE DAY
PROGRESSES. THUNDERSTORMS ARE ANTICIPATED TO BLOSSOM DURING THE
AFTERNOON AT PEAK HEATING HOWEVER THERE ARE A FEW FACTORS THAT COULD
LIMIT DEVELOPMENT. THESE FACTORS CONSIST OF HOW THE AIRMASS WILL BE
MODIFIED BY THE EARLIER CONVECTION SUNDAY NIGHT INTO EARLY MONDAY
MORNING AND HOW MUCH CLEARING WILL OCCUR EARLY MONDAY AFTERNOON. IF
CLEARING DOES OCCUR CAPE VALUES COULD SOAR TO OVER 1500 J/KG IN THE
AFTERNOON. WITH SURFACE DEWPOINTS OVER 60 DEGREES AS WELL AS 40-50
KNOT 0-6 KM SHEAR A FEW STORMS COULD BECOME SEVERE WITH LARGE HAIL
AND DAMAGING WINDS BEING THE MAIN CONCERN. MODERATE DIRECTIONAL
SHEAR WILL ALSO BE FOUND IN THE LOWER LEVELS SO AN ISOLATED TORNADO
CAN CAN NOT BE RULED OUT WITH THESE STORMS. THUNDERSTORM CHANCES
CONTINUE OVERNIGHT ACROSS SOUTH CENTRAL AND CENTRAL KANSAS AS THE
LOW LEVEL JET STRENGTHENS. A FEW OF THESE STORMS COULD ALSO BECOME
SEVERE WITH LARGE HAIL BEING THE MAIN CONCERN. DEPENDING ON HOW MUCH
CLEARING IS SEEN DURING THE AFTERNOON, HIGHS ON MONDAY ARE
ANTICIPATED TO RANGE FROM THE MID 70S ACROSS THE I-70 CORRIDOR TO
AROUND 80 ACROSS THE KS/OK BORDER. LOWS TUESDAY MORNING ARE
ANTICIPATED TO RANGE FROM THE LOWER 50S ACROSS THE KS/CO BORDER TO
LOWER 60S ACROSS SOUTH CENTRAL KANSAS WHERE DEWPOINTS WILL BE AROUND
60 DEGREES.
LEE TROUGHING DEVELOPS ACROSS EASTERN COLORADO TUESDAY MORNING IN
RESPONSE TO THE NEXT UPPER LEVEL TROUGH MOVING THROUGH THE NORTHERN
ROCKIES. SOUTHERLY WINDS WILL INCREASE IN SPEED AND BRING ADDITIONAL
LOW LEVEL MOISTURE UP FROM THE SOUTH. THIS WILL ALSO CAUSE ANOTHER
DRYLINE TO FORM ACROSS EASTERN COLORADO. MODELS SUGGEST A COLD FRONT
TO MOVE SOUTH FROM THE DAKOTAS INTO NEBRASKA AND NORTHERN KANSAS BY
WEDNESDAY MORNING. THIS WILL SHIFT THE SURFACE TROUGH AND DRYLINE
FARTHER EAST. THE AFOREMENTIONED COLD FRONT IS FORECASTED TO MOVE
FARTHER SOUTH WEDNESDAY THEN STALL OUT ACROSS CENTRAL KANSAS IN THE
AFTERNOON. A SLIGHT CHANCE OF THUNDERSTORMS WILL BE POSSIBLE
WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING ALONG AND EAST OF THE
DRYLINE AND COLD FRONT. HIGHS TUESDAY THROUGH THURSDAY ARE
FORECASTED TO RISE INTO THE 80S WITH THE POSSIBILITY OF AROUND 90
DEGREES ACROSS FAR SOUTHWESTERN KANSAS. LOWS WEDNESDAY THROUGH
FRIDAY MORNING ARE EXPECTED TO RANGE FROM THE MID 50S ACROSS THE
KS/CO BORDER TO LOWER 60S ACROSS SOUTH CENTRAL AND CENTRAL KANSAS.
EXTENDED MODELS THEN SUGGEST UPPER LEVEL RIDGING DEVELOPING ACROSS
THE SOUTHERN ROCKIES FRIDAY INTO SATURDAY WITH A TROUGH OF LOW
PRESSURE ENTERING THE WESTERN CONUS. A WEAK AREA OF LOW PRESSURE IS
DEPICTED ACROSS THE TEXAS PANHANDLE DURING THIS TIMEFRAME WHICH WILL
CONTINUE SOUTHERLY WINDS ACROSS WESTERN KANSAS. NO PRECIPITATION IS
EXPECTED AT THIS TIME WITH PARTLY CLOUDY SKIES. HIGHS FRIDAY AND
SATURDAY ARE FORECASTED TO RISE INTO THE MID TO UPPER 80S WITH LOWS
AROUND 60 DEGREES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1234 AM CDT SUN APR 29 2012
VFR CONDITIONS WILL CONTINUE WITH SCATTERED SHOWERS AND
THUNDERSTORMS INCREASING IN COVERAGE AFTER 12 TO 14Z. EXPECT MVFR
CONDITIONS WITH THUNDERSTORMS. THE STORMS WILL BE ELEVATED, WITH A
SKINNY AREA OF CAPE, NORTH OF A COLD FRONT AND LASTING INTO 06Z.
THE RAINFALL INDUCED BY RR JET CIRCULATION AND A WEAK UPPER LEVEL
TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 55 77 58 / 50 50 40 30
GCK 67 54 78 56 / 40 50 40 20
EHA 69 54 81 53 / 40 50 30 20
LBL 69 55 82 55 / 50 50 40 30
HYS 68 53 76 59 / 30 40 30 30
P28 71 59 78 62 / 70 70 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...KRUSE
LONG TERM...HOVORKA 42
AVIATION...KRUSE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
259 AM CDT SUN APR 29 2012
...UPDATED LONG TERM SECTION...
.SYNOPSIS...
ISSUED AT 359 PM CDT SAT APR 28 2012
THE NEXT 24 HOURS WILL BE A CHALLENGING FORECAST WITH CONVECTIVE
CHANCES HAVING AN IMPACT ON TEMPERATURES. ANY UPPER VORTEX IS
CURRENTLY SPINNING EASTWARD INTO THE NORTHERN PLAINS AS OBSERVED ON
INFRARED SATELLITE. TO THE SOUTH OF THIS LOW IS AN UPPER JET
STREAKING ACROSS THE CENTRAL AND SOUTHERN ROCKIES INTO THE HIGH
PLAINS REGION. IT HAS BEEN OBSERVED THAT EVEN WITH THE INCOMING NOSE
OF THE UPPER JET, NO CONVECTION HAS BEEN OBSERVED THROUGH THE
MOUNTAINS IN THE LIGHTNING DETECTION NETWORK PLOT. A STATIONARY
FRONT WAS DRAPED ACROSS CENTRAL AND WESTERN OKLAHOMA WITH HIGH
DEW POINTS IN THE MID 60S, WHILE BEHIND THE BOUNDARY LIGHT
NORTHEAST WINDS COVERED WESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 359 PM CDT SAT APR 28 2012
THE COMBINATION OF MID LEVEL INSTABILITY AND UPPER FORCING WILL BE
THE MAJOR PLAYER IN ANY CONVECTIVE EVOLUTION OVER THE NEXT 24 TO 36
HOURS. AS THE UPPER WAVE APPROACHES TONIGHT, WESTERN KANSAS WILL BE
MORE IN CLOSE PROXIMITY OF AN UPPER RIGHT ENTRANCE JET REGION,
PROMOTING A THERMALLY INDIRECT CIRCULATION. THE PREEXISTING
ATMOSPHERE WILL BE CONDITIONALLY UNSTABLE SO CONVECTION IS POSSIBLE
INCREASING FROM THE WEST OVERNIGHT. THE HIGH RESOLUTION ARW AND NMM
MODELS AND THE NAM PRODUCE QPF IN THIS ZONE BETWEEN MIDNIGHT AND
12Z. MOVING INTO THE EARLY SUNDAY MORNING TIMEFRAME, THE UPPER
TROUGH AXIS WILL ROTATE CLOSER TO WESTERN KANSAS INCREASING THE
HEIGHT GRADIENT AND PVA WHILE THE MODELS BEGIN TO LIFT THE
STATIONARY FRONT ACROSS WESTERN OKLAHOMA CLOSER TO THE
OKLAHOMA/KANSAS LINE LATE SUNDAY. AS A RESULT, ADDITIONAL
THUNDERSTORM CHANCES ARE WARRANTED THROUGH THE DAY ON SUNDAY. NAM
MODEL SHOWS SBCAPES INCREASING IN EXCESS OF 1000 J/KG, ESPECIALLY
ACROSS THE SOUTHWEST/WESTERN AND SOUTHERN SECTIONS OF KANSAS.
AS THE UPPER JET AND TROUGH MOVES THROUGH THE AREA ON SUNDAY,
ADDITIONAL THUNDERSTORMS CHANCES ARE EXPECTED THROUGH THE DAY AS THE
ATMOSPHERE DESTABILIZES AGAIN DIURNALLY. THE POSITION OF THE FRONT
TO THE SOUTH WILL BE THE MAIN FOCUS FOR CONVECTION, ESPECIALLY
SEVERE CONVECTION. HOWEVER, FROM MODEL LOW LEVEL FIELDS, IT APPEARS
SOUTHWEST KANSAS WILL BE ON THE NORTH SIDE OF THE BOUNDARY, SO THE
SEVERE POTENTIAL COULD BE RELEGATED PRIMARILY TO HAIL AND WIND
THREATS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 258 AM CDT SUN APR 29 2012
AN UPPER LEVEL LONG WAVE TROUGH WILL BE FOUND ACROSS THE ROCKIES AS
THE LONG TERM PERIOD BEGINS WITH A SERIES OF WEAK SHORTWAVES MOVING
ACROSS THE CENTRAL PLAINS. A JET STREAK WILL BE EXITING THE CENTRAL
PLAINS ON MONDAY AND PLACE SOUTHWEST KANSAS IN THE RIGHT ENTRANCE
REGION. THIS WILL ENHANCE LIFT ACROSS OUR AREA. A WEAK SURFACE LOW
WILL BE FOUND ACROSS FAR WESTERN KANSAS IN THE MORNING WITH A
FRONTAL BOUNDARY EXTENDING EASTWARD ACROSS CENTRAL KANSAS. WINDS
WILL GENERALLY BE FROM THE SOUTH SOUTHEAST WHICH WILL CONTINUE TO
BRING AMPLE MOISTURE TO THE AREA. A DRYLINE WILL BE FOUND ACROSS THE
KS/CO BORDER IN THE MORNING THEN SHIFT EASTWARD AS THE DAY
PROGRESSES. THUNDERSTORMS ARE ANTICIPATED TO BLOSSOM DURING THE
AFTERNOON AT PEAK HEATING HOWEVER THERE ARE A FEW FACTORS THAT COULD
LIMIT DEVELOPMENT. THESE FACTORS CONSIST OF HOW THE AIRMASS WILL BE
MODIFIED BY THE EARLIER CONVECTION SUNDAY NIGHT INTO EARLY MONDAY
MORNING AND HOW MUCH CLEARING WILL OCCUR EARLY MONDAY AFTERNOON. IF
CLEARING DOES OCCUR CAPE VALUES COULD SOAR TO OVER 1500 J/KG IN THE
AFTERNOON. WITH SURFACE DEWPOINTS OVER 60 DEGREES AS WELL AS 40-50
KNOT 0-6 KM SHEAR A FEW STORMS COULD BECOME SEVERE WITH LARGE HAIL
AND DAMAGING WINDS BEING THE MAIN CONCERN. MODERATE DIRECTIONAL
SHEAR WILL ALSO BE FOUND IN THE LOWER LEVELS SO AN ISOLATED TORNADO
CAN CAN NOT BE RULED OUT WITH THESE STORMS. THUNDERSTORM CHANCES
CONTINUE OVERNIGHT ACROSS SOUTH CENTRAL AND CENTRAL KANSAS AS THE
LOW LEVEL JET STRENGTHENS. A FEW OF THESE STORMS COULD ALSO BECOME
SEVERE WITH LARGE HAIL BEING THE MAIN CONCERN. DEPENDING ON HOW MUCH
CLEARING IS SEEN DURING THE AFTERNOON, HIGHS ON MONDAY ARE
ANTICIPATED TO RANGE FROM THE MID 70S ACROSS THE I-70 CORRIDOR TO
AROUND 80 ACROSS THE KS/OK BORDER. LOWS TUESDAY MORNING ARE
ANTICIPATED TO RANGE FROM THE LOWER 50S ACROSS THE KS/CO BORDER TO
LOWER 60S ACROSS SOUTH CENTRAL KANSAS WHERE DEWPOINTS WILL BE AROUND
60 DEGREES.
LEE TROUGHING DEVELOPS ACROSS EASTERN COLORADO TUESDAY MORNING IN
RESPONSE TO THE NEXT UPPER LEVEL TROUGH MOVING THROUGH THE NORTHERN
ROCKIES. SOUTHERLY WINDS WILL INCREASE IN SPEED AND BRING ADDITIONAL
LOW LEVEL MOISTURE UP FROM THE SOUTH. THIS WILL ALSO CAUSE ANOTHER
DRYLINE TO FORM ACROSS EASTERN COLORADO. MODELS SUGGEST A COLD FRONT
TO MOVE SOUTH FROM THE DAKOTAS INTO NEBRASKA AND NORTHERN KANSAS BY
WEDNESDAY MORNING. THIS WILL SHIFT THE SURFACE TROUGH AND DRYLINE
FARTHER EAST. THE AFOREMENTIONED COLD FRONT IS FORECASTED TO MOVE
FARTHER SOUTH WEDNESDAY THEN STALL OUT ACROSS CENTRAL KANSAS IN THE
AFTERNOON. A SLIGHT CHANCE OF THUNDERSTORMS WILL BE POSSIBLE
WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING ALONG AND EAST OF THE
DRYLINE AND COLD FRONT. HIGHS TUESDAY THROUGH THURSDAY ARE
FORECASTED TO RISE INTO THE 80S WITH THE POSSIBILITY OF AROUND 90
DEGREES ACROSS FAR SOUTHWESTERN KANSAS. LOWS WEDNESDAY THROUGH
FRIDAY MORNING ARE EXPECTED TO RANGE FROM THE MID 50S ACROSS THE
KS/CO BORDER TO LOWER 60S ACROSS SOUTH CENTRAL AND CENTRAL KANSAS.
EXTENDED MODELS THEN SUGGEST UPPER LEVEL RIDGING DEVELOPING ACROSS
THE SOUTHERN ROCKIES FRIDAY INTO SATURDAY WITH A TROUGH OF LOW
PRESSURE ENTERING THE WESTERN CONUS. A WEAK AREA OF LOW PRESSURE IS
DEPICTED ACROSS THE TEXAS PANHANDLE DURING THIS TIMEFRAME WHICH WILL
CONTINUE SOUTHERLY WINDS ACROSS WESTERN KANSAS. NO PRECIPITATION IS
EXPECTED AT THIS TIME WITH PARTLY CLOUDY SKIES. HIGHS FRIDAY AND
SATURDAY ARE FORECASTED TO RISE INTO THE MID TO UPPER 80S WITH LOWS
AROUND 60 DEGREES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1234 AM CDT SUN APR 29 2012
VFR CONDITIONS WILL CONTINUE WITH SCATTERED SHOWERS AND
THUNDERSTORMS INCREASING IN COVERAGE AFTER 12 TO 14Z. EXPECT MVFR
CONDITIONS WITH THUNDERSTORMS. THE STORMS WILL BE ELEVATED, WITH A
SKINNY AREA OF CAPE, NORTH OF A COLD FRONT AND LASTING INTO 06Z.
THE RAINFALL INDUCED BY RR JET CIRCULATION AND A WEAK UPPER LEVEL
TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 68 55 77 58 / 40 50 40 30
GCK 67 54 78 56 / 50 50 40 20
EHA 69 54 81 53 / 60 50 30 20
LBL 69 55 82 55 / 50 50 40 30
HYS 66 53 76 59 / 30 40 30 30
P28 68 59 78 62 / 70 50 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...HOVORKA 42
AVIATION...KRUSE
AREA FORECAST DISCUSSION...UPDATED
NWS DODGE CITY KS
1241 AM CDT SUN APR 29 2012
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 359 PM CDT SAT APR 28 2012
THE NEXT 24 HOURS WILL BE A CHALLENGING FORECAST WITH CONVECTIVE
CHANCES HAVING AN IMPACT ON TEMPERATURES. ANY UPPER VORTEX IS
CURRENTLY SPINNING EASTWARD INTO THE NORTHERN PLAINS AS OBSERVED ON
INFRARED SATELLITE. TO THE SOUTH OF THIS LOW IS AN UPPER JET
STREAKING ACROSS THE CENTRAL AND SOUTHERN ROCKIES INTO THE HIGH
PLAINS REGION. IT HAS BEEN OBSERVED THAT EVEN WITH THE INCOMING NOSE
OF THE UPPER JET, NO CONVECTION HAS BEEN OBSERVED THROUGH THE
MOUNTAINS IN THE LIGHTNING DETECTION NETWORK PLOT. A STATIONARY
FRONT WAS DRAPED ACROSS CENTRAL AND WESTERN OKLAHOMA WITH HIGH
DEW POINTS IN THE MID 60S, WHILE BEHIND THE BOUNDARY LIGHT
NORTHEAST WINDS COVERED WESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 359 PM CDT SAT APR 28 2012
THE COMBINATION OF MID LEVEL INSTABILITY AND UPPER FORCING WILL BE
THE MAJOR PLAYER IN ANY CONVECTIVE EVOLUTION OVER THE NEXT 24 TO 36
HOURS. AS THE UPPER WAVE APPROACHES TONIGHT, WESTERN KANSAS WILL BE
MORE IN CLOSE PROXIMITY OF AN UPPER RIGHT ENTRANCE JET REGION,
PROMOTING A THERMALLY INDIRECT CIRCULATION. THE PREEXISTING
ATMOSPHERE WILL BE CONDITIONALLY UNSTABLE SO CONVECTION IS POSSIBLE
INCREASING FROM THE WEST OVERNIGHT. THE HIGH RESOLUTION ARW AND NMM
MODELS AND THE NAM PRODUCE QPF IN THIS ZONE BETWEEN MIDNIGHT AND
12Z. MOVING INTO THE EARLY SUNDAY MORNING TIMEFRAME, THE UPPER
TROUGH AXIS WILL ROTATE CLOSER TO WESTERN KANSAS INCREASING THE
HEIGHT GRADIENT AND PVA WHILE THE MODELS BEGIN TO LIFT THE
STATIONARY FRONT ACROSS WESTERN OKLAHOMA CLOSER TO THE
OKLAHOMA/KANSAS LINE LATE SUNDAY. AS A RESULT, ADDITIONAL
THUNDERSTORM CHANCES ARE WARRANTED THROUGH THE DAY ON SUNDAY. NAM
MODEL SHOWS SBCAPES INCREASING IN EXCESS OF 1000 J/KG, ESPECIALLY
ACROSS THE SOUTHWEST/WESTERN AND SOUTHERN SECTIONS OF KANSAS.
AS THE UPPER JET AND TROUGH MOVES THROUGH THE AREA ON SUNDAY,
ADDITIONAL THUNDERSTORMS CHANCES ARE EXPECTED THROUGH THE DAY AS THE
ATMOSPHERE DESTABILIZES AGAIN DIURNALLY. THE POSITION OF THE FRONT
TO THE SOUTH WILL BE THE MAIN FOCUS FOR CONVECTION, ESPECIALLY
SEVERE CONVECTION. HOWEVER, FROM MODEL LOW LEVEL FIELDS, IT APPEARS
SOUTHWEST KANSAS WILL BE ON THE NORTH SIDE OF THE BOUNDARY, SO THE
SEVERE POTENTIAL COULD BE RELEGATED PRIMARILY TO HAIL AND WIND
THREATS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 356 PM CDT SAT APR 28 2012
EARLY IN THE PERIOD (SUNDAY NIGHT) THE WEATHER WILL BE INFLUENCED BY
WHAT OCCURS TONIGHT AND SUNDAY AND IF THIS WILL DRIVE THE SURFACE
BOUNDARY BACK SOUTH. HOWEVER, WITH THE ROCKIES UPPER S/WV LIFTING
INTO THE MID-WEST AND WITH SURFACE PRESSURE FALLS IN THE FRONT RANGE
IT DOES APPEAR LIKELY THAT THE FRONT WILL LIFT NORTH. THERE SHOULD
BE CONVECTION MOVING OFF THE HIGHER TERRAIN SUNDAY NIGHT AND THIS
MAY LINGER INTO EARLY MONDAY AS THE AFOREMENTIONED FRONT MOVES
NORTH. DURING THE DAY MONDAY AND INTO MONDAY NIGHT ADDITIONAL
CONVECTION WILL BE POSSIBLE IN THE PRESENCE OF MID-LEVEL INSTABILITY
AND A DRY LINE THAT WILL EVENTUALLY MIX OUT OF EASTERN COLORADO INTO
MY WESTERN COUNTIES. HOWEVER, STILL THERE IS A LOT OF UNCERTAINTY
DEPENDING ON PREVIOUS CONVECTION THAT WILL NO DOUBT MODIFY THE
AIRMASS.
WITH CONTINUED WESTERLY FLOW DURING THE WEEK AND WITH LEE SIDE
PRESSURE FALLS THE DRY LINE SHOULD DIURNALLY RETREAT INTO EASTERN
COLORADO AT NIGHT AND MIX EAST DURING THE DAY. UNCERTAINTY WILL
EXIST HOWEVER ON WARMING ALOFT AND WHETHER FORCING WILL BE
SUFFICIENT TO PRODUCE ADDITIONAL THUNDERSTORMS. THUS, POPS WILL
REMAIN LOW DURING THE LATER PERIODS. TEMPERATURES WILL BE ABOVE
NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1234 AM CDT SUN APR 29 2012
VFR CONDITIONS WILL CONTINUE WITH SCATTERED SHOWERS AND
THUNDERSTORMS INCREASING IN COVERAGE AFTER 12 TO 14Z. EXPECT MVFR
CONDITIONS WITH THUNDERSTORMS. THE STORMS WILL BE ELEVATED, WITH A
SKINNY AREA OF CAPE, NORTH OF A COLD FRONT AND LASTING INTO 06Z.
THE RAINFALL INDUCED BY RR JET CIRCULATION AND A WEAK UPPER LEVEL
TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 77 57 87 / 50 30 30 10
GCK 52 78 55 88 / 50 30 20 10
EHA 52 81 52 89 / 50 30 20 0
LBL 53 82 54 90 / 50 30 20 0
HYS 50 76 58 84 / 40 20 30 20
P28 57 78 61 83 / 50 30 30 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...HUTTON
AVIATION...KRUSE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
200 AM EDT SUN APR 29 2012
.UPDATE...
ISSUED AT 200 AM EDT SUN APR 29 2012
UPDATED THE FORECAST TO MAINLY ADJUST THE POP...WX AND SKY GRIDS
GIVEN THE EVOLUTION OF THE CONVECTION TO THE NORTHWEST AND EXPECTED
GRADUAL DISSIPATION IN OUR AREA LATER THIS MORNING. ALSO TWEAKED THE
TEMP AND DEWPOINT GRIDS FOR CURRENT OBSERVATIONS AND TRENDS.
UPDATE ISSUED AT 1039 PM EDT SAT APR 28 2012
UPDATED THE FORECAST TO REFLECT CURRENT CONDITIONS AND MODEL TRENDS.
THE STORMS HAVE WEAKENED SO TOOK OUT ANY MENTION OF SEVERE
THUNDERSTORMS OUT OF THE FORECAST. THE REST OF THE FORECAST IS ON
TRACK.
UPDATE ISSUED AT 905 PM EDT SAT APR 28 2012
WE HAVE BEEN MONITORING THUNDERSTORMS UPSTREAM OVER CENTRAL AND NORTH
CENTRAL KENTUCKY. ONE OF THESE STORMS HAS PRODUCED BASEBALL SIZED
HAIL OVER SOUTHERN INDIANA. THERE IS A GENERAL WEAKENING TREND FOR
THESE STORMS AS THEY MOVE EAST SOUTHEAST TOWARDS EASTERN KENTUCKY.
EXTRAPOLATING THE MOVEMENT OF THE STRONGEST STORM WOULD HAVE IT
MOVING INTO ESTILL COUNTY AROUND 11 PM. HAVE UPDATED THE FORECAST TO
REFLECT THE CURRENT CONDITIONS AND MODEL TRENDS.
UPDATE ISSUED AT 512 PM EDT SAT APR 28 2012
UPDATED THE FORECAST TO REFLECT CURRENT CONDITIONS AND MODEL TRENDS.
THE AIRMASS OVER THE AREA REMAINS QUITE UNSTABLE BUT CAPPED. THE
MODELS ARE SHOWING THAT THE CAPPING SHOULD BE DECREASING AS THE FRONT
PUSHES SOUTH BACK INTO EASTERN KENTUCKY. WITH THE
INSTABILITY...CONVECTION COULD BUILD ABOUT ANYWHERE...BUT RIGHT
NOW...THE BEST BET IS THAT SOMETHING WILL DEVELOP FROM OUTFLOWS FROM
THE STORMS CURRENTLY OVER THE ILLINOIS/INDIANA BORDER. THE HRRR MODEL
IS SHOWING SOME CONVECTION FORMING NORTH OF I-64 BY 8 PM. WILL
CONTINUE TO MONITOR CLOSELY. WE HAVE GASOLINE...WE JUST NEED A MATCH.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 330 PM EDT SAT APR 28 2012
CONVECTION STILL HAVING A HARD TIME INITIATING THIS AFTERNOON WITH
19Z SFC ANALYSIS INDICATING THE WARM FRONT CURRENTLY BISECTING THE
COMMONWEALTH FROM WEST TO EAST. TO THE SOUTH OF THE BOUNDARY...SFC
TEMPS IN THE UPPER 70S COUPLED WITH DEW POINTS APPROACHING 60 DEGREES
HAS RESULTED IN SOME DECENT SFC BASED INSTABILITY. HOWEVER...BOTH THE
NAM AND GFS BUFR SOUNDINGS DO STILL SHOW ENOUGH OF A CAP TO LIMIT
CONVECTIVE POTENTIAL SOUTH OF THE HAL ROGERS AND TO A LESSER EXTENT
SOUTH OF THE MTN PARKWAY AS WELL. TO THE NORTH...DEBRIS FROM ACTIVITY
IN IN/OH EARLIER TODAY HAS PUT A LIMIT ON THE TEMP RECOVERY WITH THE
MERCURY JUST STARTING TO CREEP INTO THE MID 60S...THOUGH DEW POINTS IN
THE UPPER 40S TO LOWER 50S HAS PRECLUDED ANY SIGNIFICANT INSTABILITY
FROM DEVELOPING.
FORECAST CHALLENGE FOR THE REMAINDER OF THE AFTERNOON AND EVENING
REMAINS POPS...CONVECTIVE POTENTIAL...AND THE THREAT FOR SEVERE
STORMS. CURRENT SAT IMAGERY SHOWS ANOTHER SHORT WAVE MOVING THRU
CENTRAL IL RIDING ALONG THE SFC BOUNDARY DRAPED ALONG THE OHIO RIVER.
THIS WAVE IS ON PACE TO REACH OUR BLUEGRASS LATER THIS EVENING...WHEN
FCST SOUNDINGS SHOW A DECLINE IN CAPE. NOT REALLY SEEING ANY
APPRECIABLE OUTFLOW BOUNDARIES FROM ACTIVITY TO THE NORTH...THOUGH
WOULD SUSPECT THAT THERE IS AT LEAST 1 OR 2 THAT WOULD BE PUSHING
SOUTH AND WOULD ENHANCE THE FRONTAL BOUNDARY WHICH WILL SERVE AS THE
FOCUS FOR ANY STORMS THIS AFTERNOON AND EVENING. BEST CHANCES FOR
SEVERE STORMS THIS GO AROUND APPEAR TO BE NORTH OF THE MTN PARKWAY
THRU SUNSET. THEREAFTER...LACK OF UPPER LEVEL DYNAMICS AND THE USUAL
DECLINE IN SFC BASED INSTABILITY WITH THE SUNSET SHOULD CURTAIL ANY
SEVERE THREAT OVERNIGHT...THOUGH WILL NOT COMPLETELY RULE OUT SOME
TSTM ACTIVITY OVERNIGHT AS THE FRONT BEGINS TO SAG BACK TO THE SOUTH.
SHORTWAVE RIDGING TRAVERSES THE LOWER AND MID OHIO VALLEY ON SUNDAY
AND SHOULD LIMIT ANY SIGNIFICANT PRECIP CHANCES THROUGH SUNDAY NIGHT.
WILL CARRY A SLIGHT CHANCE FOR TSTMS ON SUNDAY WITH LOW LEVEL
MOISTURE LINGERING OVER THE AREA AND A POTENTIALLY ACTIVE BOUNDARY
STILL DRAPED OVER THE AREA. TEMPERATURES WILL VARY CONSIDERABLY
DEPENDING ON WHERE THE BOUNDARY ENDS UP...WITH MID TO UPPER 60S
EXPECTED NORTH OF THE FRONT ON SUNDAY AND UPPER 70S TO THE SOUTH. THE
SPREAD AMONG THE LOWS TONIGHT AND SUNDAY NIGHT SHOULD BE MORE
LIMITED GIVEN THE EXPECTED CLOUD COVER...BUT WILL GENERALLY RANGE
FROM AROUND 50 IN THE NORTH TO AROUND 60 IN THE SOUTH.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 330 PM EDT SAT APR 28 2012
LOOKING AT A NEARLY ZONAL...OR LOW AMPLITUDE UPPER PATTERN THROUGH
THE EXTENDED WITH GENERALLY SOUTHWEST FLOW OVER EASTERN KENTUCKY
THROUGH THE BULK OF THE PERIOD. OUR CWA REMAINS FAIRLY CLOSE TO THE
MEAN WESTERLIES HOWEVER AND AS SUCH WILL BE SUSCEPTIBLE TO SEVERAL
WEAK IMPULSES TRAVELING THROUGH THE MEAN FLOW. TIMING OF THESE
IMPULSES WILL BE TRICKY AS MODELS TYPICALLY HAVE TROUBLE IN THIS
TYPE OF PATTERN. LOW AMPLITUDE MEAN TROUGH POSITIONED OVER THE
WESTERN CONUS DOES TEND TO MOVE EASTWARD WITH TIME AND APPEARS TO
HAVE THE MOST SIGNIFICANT IMPACT ON OUR WEATHER TOWARDS THE END OF
THE WEEK.
FOR SENSIBLE WEATHER...BROAD BRUSH POPS WOULD PROBABLY BE BEST
APPROACH. BUT DECIDED TO FOCUS POPS WITH BEST GUESS AT TIMING OF
SHORT WAVE IMPULSES. LINED UP HIGHER POPS FOR A MONDAY NIGHT THROUGH
TUESDAY EVENING TIME FRAME. SHORT WAVE RIDGING AHEAD OF TROUGH
PULLING OUT OF THE WESTERN CONUS WILL MORE THAN LIKELY KEEP
WEDNESDAY DRY AS A CAP KEEP CONVECTION AT A MINIMUM. UNSETTLED
WEATHER RETURNS AT THE END OF THE EXTENDED...LATE THURSDAY OR FRIDAY
AS TROUGH ROLLS INTO THE REGION.
BEING ON THE SOUTH SIDE OF MEAN FLOW TEMPERATURES SHOULD AVERAGE
ABOVE NORMAL THROUGH THE WEEK. BUT COOLER...MORE NORMAL WEATHER
SHOULD RETURN WITH THE ARRIVAL OF AFOREMENTIONED TROUGH AT THE END
OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 200 AM EDT SUN APR 29 2012
A CLUSTER OF THUNDERSTORMS OVER CENTRAL KENTUCKY ARE TRENDING
WEAKER...HOWEVER THERE IS STILL A POSSIBLY TO SEE THEIR REMNANTS MAKE
IT INTO THE FORECAST AREA OVER THE NEXT SEVERAL HOURS. THE AVN GRIDS
HAVE BEEN ADJUSTED WITH THIS THOUGHT IN MIND...THOUGH FOR THE
OFFICIAL TAF SITES QUIET WX SHOULD BE THE RULE THROUGH THE PERIOD.
SOME MVFR FOG WILL BE POSSIBLE IN THE PREDAWN HOURS AT LOZ AND SME
SHOULD THE THICKER CLOUDS ALOFT THIN AS THE THUNDERSTORMS CONJURING
THEM WANE. ANY CONVECTION IN THE AREA ON SUNDAY WILL BE PRIMARILY
WELL NORTH OF THE TAF SITES SO HAVE KEEP THEM CLEAN...THOUGH MID
LEVEL CLOUDS WILL LIKELY REMAIN PLENTIFUL THROUGH THE DAY. WINDS WILL
BE GENERALLY LIGHT AND VARIABLE...AWAY FROM ANY STORM THROUGH SUNDAY
NIGHT...AS WELL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...MB
LONG TERM....RAY
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS BILLINGS MT
345 AM MDT SUN APR 29 2012
.SHORT TERM...VALID FOR TDY AND MON...
MOISTURE CHANNEL IMAGERY AND RUC OBJECTIVE ANALYSES PLACE THE MID-
LEVEL LOW JUST WEST OF DICKINSON ND AT 09 UTC. TODAY WILL MARK THE
EXIT OF THIS FEATURE AND THE END OF THE RECENT WET WEATHER...AND A
RETURN TO A MORE SEASONABLE /BUT STILL UNSETTLED/ PERIOD.
EARLY THIS MORNING...THE REMAINS OF THE WELL-DEVELOPED TROWAL HAVE
MADE THEIR WAY AS FAR WEST AS HARLOWTON AND BILLINGS. WE WILL NEED
TO KEEP LIKELY POPS IN THE FORECAST THROUGH 18 UTC WHERE THIS AREA
IS LINGERING...BUT THE WARM CONVEYOR BELT OF THE MID-LEVEL WAVE IS
DIMINISHING QUICKLY...SO THIS MOISTURE WILL BEGIN DECREASING LIKE
MODEL SOLUTIONS ALL SUGGEST. HOWEVER...IT OFTEN TAKES SOME TIME IN
ORDER FOR THIS TO OCCUR...AND INDEED THERE ARE STILL HINTS OF SOME
PRESSURE ADVECTION ON THE 290 K ISENTROPIC SURFACES THROUGHOUT THE
MORNING...SO WE DO NOT EXPECT THE PRECIPITATION TO END SUDDENLY BY
ANY MEANS. EVEN SO...THE RATES ARE ON THE WAY DOWN...SO WE DECIDED
TO CANCEL ALL OF THE WINTER WEATHER HEADLINES JUST A BIT EARLY.
FOR THE REST OF THE DAY...WE WILL KEEP SHOWER CHANCES GOING DUE TO
LINGERING CYCLONIC FLOW AND SOME LOW-LEVEL INSTABILITY REVEALED ON
FORECAST SOUNDINGS. HIGHS WILL PROBABLY NOT BE ABLE TO TOP 50 F IN
PARTS OF SOUTHEASTERN MT WHERE 850-HPA TEMPERATURES DO NOT RECOVER
TO +4 C UNTIL 00 UTC.
TONIGHT...WE HAVE DECIDED TO INCLUDE A MENTION OF PATCHY FOG AFTER
06 UTC ON THE PLAINS OF SOUTHEASTERN AND PART OF SOUTH CENTRAL MT.
ENHANCED NEAR-SURFACE MOISTURE DUE TO THE RECENT RAINFALL IS GOING
TO BE TRAPPED BENEATH A RADIATION INVERSION...WHICH COULD YIELD AT
LEAST SOME FOG IN LOW-LYING AREAS. BUFKIT-BASED TOOLS USING THE 00
UTC NAM SUPPORT THIS IDEA IN PLACES LIKE MILES CITY AND BAKER WITH
MINIMAL MIXING IN THE NEAR-SURFACE LAYER. ON THE OTHER HAND...MOST
OF THE GFS SOUNDINGS HAVE JUST ENOUGH LOW-LEVEL FLOW TO KEEP THOSE
BUFKIT TOOLS FROM SUGGESTING FOG. NONE OF THE MOS GUIDANCE SHOWS A
HINT OF FOG EITHER...SO THIS IS FAR FROM A SURE THING...THOUGH THE
RECENT MOISTURE IN AND OF ITSELF IS PERHAPS THE BEST INDICATOR.
MON...FLOW ALOFT WILL QUICKLY BACK AND LOW- AND MID-LEVEL WARM AIR
ADVECTION WILL OCCUR AHEAD OF A PACIFIC SHORT WAVE TROUGH. THIS IS
A DIFFICULT TEMPERATURE FORECAST THOUGH...AS MIXING TO 700 HPA MAY
BE OFFSET BY SIGNIFICANT MID- OR HIGH-LEVEL CLOUDS...AND INCREASED
GROUND MOISTURE ON THE PLAINS. THUS...OUR HIGHS ARE ACTUALLY A BIT
BELOW THE MULTI-MODEL CONSENSUS IN MANY CASES AT THIS POINT. THERE
WILL BE SHOWER CHANCES SPREADING FROM WEST TO EAST BY MON EVENING.
HOWEVER...THE EXIT REGION AND SUPPORTIVE UPPER-LEVEL DIVERGENCE OF
AN 80 KT 300-HPA JET STREAK WILL ACTUALLY BE FOCUSED OVER NORTHERN
MT...AND MID-LEVEL LAPSE RATES ARE NOT PARTICULARLY STEEP. POPS IN
THE LOWER ELEVATIONS ARE THUS MAINLY IN THE 20 TO 40 PERCENT RANGE
AT THIS POINT. ISOLATED THUNDERSTORMS ARE ALSO MENTIONED FOR PARTS
OF SOUTH CENTRAL MT...BUT WITH MUCAPE LESS THAN 250 J/KG ON THE 00
UTC GFS AND NAM...THAT MAY ACTUALLY BE REMOVED LATER. SCHULTZ
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MODELS WERE IN FAIR AGREEMENT THROUGH FRIDAY...BUT NOT SO MUCH
FROM SATURDAY ONWARD. THERE WERE EVEN SOME SMALL DIFFERENCES IN
THE TIME OF AGREEMENT. THESE DIFFERENCES WERE ON OVERALL STRENGTH
AND TIMING OF SHORTWAVES IN A BROAD TROUGH PROGGED FOR TUESDAY
AND WEDNESDAY. ENERGY OVER THE ALEUTIAN ISLANDS WILL DROP INTO
THE PACIFIC NORTHWEST ON MONDAY. THIS ENERGY WILL MOVE INTO
WESTERN MONTANA EARLY TUESDAY AND CARVE OUT A BROAD TROUGH OVER
THE NORTHERN ROCKIES. THIS TROUGH WILL REMAIN IN PLACE FOR A
COUPLE OF DAYS AS ONE CHUNK OF ENERGY MOVES NORTHEAST INTO SOUTH
CENTRAL CANADA WHILE ANOTHER WAVE DROPS INTO THE PACIFIC
NORTHWEST. THIS WILL KEEP THE FORECAST SOMEWHAT UNSETTLED WITH
THE MOUNTAINS RECEIVING THE BEST SHOT OF SHOWERS. HAVE LOWERED
HIGHS A COUPLE OF DEGREES TUESDAY AND WEDNESDAY WITH LOW MID
LEVEL HEIGHTS.
THE SECONDARY PIECE OF ENERGY MOVING INTO THE TROUGH MENTIONED
ABOVE EXITS THE AREA WEDNESDAY NIGHT WITH A SMALL SCALE RIDGE
MOVING IN THURSDAY. THIS WILL BE SHORT LIVED HOWEVER AS DEEPENING
SHORTWAVE FLOW ALOFT WILL ALLOW SEVERAL WAVES OF ENERGY AND
MOISTURE TO STREAM INTO THE FORECAST AREA. THE MOUNTAINS WILL
RECEIVE THE BULK OF THE PRECIPITATION CHANCES...BUT THE PLAINS
WILL ALSO GET SCATTERED POPS WITH LOW LEVEL NORTHERLY FLOW. THE
STRONGEST POP DAY WILL LIKELY BE ON SATURDAY AS THE WESTERN
TROUGH KICKS ACROSS THE AREA. NOW THE ECMWF DOES NOT SWING THE
TROUGH INTO THE AREA. THE ECMWF DROPS THE TROUGH SOUTH IN
SPLITTING FLOW AND CUTS THE SOUTHERN STREAM OFF IN NEVADA.
MONTANA WOULD GET UPPER DIVERGENCE FORCING ON SUNDAY...WITH
SATURDAY BEING RELATIVELY DRY. DID NOT CHANGE POPS MUCH FOR THE
WEEKEND AS NEED TO GET THESE MODEL DIFFERENCES RESOLED BEFORE
PUSHING IN THE WET OR DRY DIRECTION. WILL LEAVE IN LOW SCATTERED
POPS FOR NOW. TWH
&&
.AVIATION...
A BAND OF LIGHT RAIN AND LIGHT SNOW WILL LINGER OVER CENTRAL AND
EASTERN SECTIONS THIS MORNING. KBIL WILL BE NEAR THE WESTERN EDGE
OF THE PRECIPITATION...WITH THE HEAVIEST PRECIPITATION FALLING
BETWEEN KBIL AND KMLS. FREQUENT MVFR CONDITIONS WILL OCCUR WITHIN
THE PRECIPITATION WITH OCCASIONAL IFR CONDITIONS EXPECTED.
MOUNTAINS WILL BE OBSCURED. THE PRECIPITATION WILL TAPER OFF
THROUGH THE MORNING WITH CONDITIONS IMPROVING TO MAINLY VFR THIS
AFTERNOON. GUSTY WEST TO NORTHWEST WINDS WILL DECREASE THIS
MORNING. CLOUDS WILL DECREASE THIS AFTERNOON AND TONIGHT. PATCHY
FOG WILL BE POSSIBLE EAST OF KBIL TONIGHT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 056 039/067 045/063 039/063 041/066 045/068 045/065
6/R 12/W 33/T 21/B 11/B 11/B 22/W
LVM 055 034/059 037/058 032/057 033/061 036/063 037/061
3/R 23/W 44/T 21/B 12/W 22/W 23/W
HDN 056 035/069 046/065 039/065 040/068 043/070 044/067
7/R 11/B 23/T 21/B 11/B 11/B 22/W
MLS 050 037/069 048/065 041/065 041/065 045/069 046/067
7/R 21/B 22/T 22/W 11/B 11/B 22/W
4BQ 050 034/069 048/066 040/065 040/067 044/070 044/067
6/O 11/B 23/T 21/B 11/B 11/B 23/W
BHK 048 034/067 047/064 040/063 040/064 044/068 043/067
7/R 21/B 22/T 22/W 11/B 11/B 23/W
SHR 053 033/065 042/062 036/062 037/065 040/068 040/064
4/O 11/B 23/T 21/B 11/B 11/B 23/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
345 AM EDT SUN APR 29 2012
.SYNOPSIS...
A STATIONARY FRONT OVER SOUTH CAROLINA WILL MOVE BRIEFLY NORTH
ALONG THE COAST AS A WARM FRONT TONIGHT BEFORE MOVING BACK SOUTH
AS A COLD FRONT ON SUNDAY AND SUNDAY NIGHT. THE FRONT SHOULD
DISSIPATE SOUTH OF THE AREA MONDAY AS HIGH PRESSURE BUILDS IN FROM
THE EAST TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1240 AM SUN...UPDATED FOR CURRENT PT CLDY SKIES OVER SRN HALF
OF AREA...AND DROPPED POPS UNTIL AFTER 2 A FOR NRN SECTIONS. ALSO
LOWERED MIN TEMPS BASEDO ON CURRENT OBS AS EVENING CLEARING ALLOWED
MORE COOLING.
/PREVIOUS DISCUSSION/
AS OF 955 PM SATURDAY...THE LOW CLOUDS HAVE DISSIPATED MUCH FASTER
AND OVER A MORE WIDESPREAD AREA THAN PREVIOUSLY EXPECTED THIS
EVENING. PERHAPS THIS IS DUE IN PART TO SUBSIDENCE SEEN IN THE OMEGA
FORECASTS AS A WEAK LOW MOVES AWAY FROM THE NC COAST. BOTH THE 00Z
GSO AND MHX SOUNDINGS WERE DEEPLY SATURATED IN THE LOW
LEVELS...EXHIBITED SHARP LOW LEVEL INVERSIONS...AND LOW LEVEL
EASTERLY FLOW...ALL SUGGESTIVE OF CONDITIONS FAVORABLE FOR LOW CLOUD
REDEVELOPMENT LATER TONIGHT. THE 18Z NAM-12 FORECAST SOUNDINGS STILL
SUPPORTED LOW CLOUDS BUT WITH SHALLOWER LOW LEVEL MOISTURE. GIVEN A
SURFACE PATTERN INDICATIVE OF HYBRID DAMMING AND THE ABOVE FACTORS I
AM STILL EXPECTING WIDESPREAD LOW CLOUDS BUT NOT WITH AS MUCH
CONFIDENCE AS BEFORE. REMNANT SHOWERS FROM AN UPSTREAM MCS COULD
AFFECT THE NORTHERN PORTION OF THE AREA LATE SO WILL MAINTAIN 20-30%
POPS NORTH FOR LATE TONIGHT.
THE STATIONARY BOUNDARY CURRENTLY LOCATED FROM NORTHEAST SOUTH
CAROLINA INTO EXTREME SOUTHEAST NORTH CAROLINA IS STILL EXPECTED
TO LIFT NORTH OVERNIGHT...MAINLY ALONG THE IMMEDIATE COAST. THIS
WILL RESULT IN THE FLOW TURNING FROM EASTERLY TO SOUTHWEST ALONG
AND NEAR THE COAST. FURTHER INLAND A HYBRID DAMMING PATTERN WILL
REMAIN AND RETARD THE NORTHWARD MOVEMENT OF THE RETREATING
BOUNDARY WITH NORTHERLY FLOW PERSISTING. STILL EXPECTING LOW
TEMPERATURES 53 TO 58 INLAND WITH TEMPERATURES BRIEFLY RISING
ALONG THE COAST SHOULD THE SW FLOW MATERIALIZE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
AS OF 245 PM SATURDAY...THE COLD FRONT WILL DRIVE TO THE SOUTH OF
THE AREA AGAIN ON SUNDAY WITH THE NAM12 AND GFS SHOWING A BROKEN
BAND OF MOISTURE AND AGAIN A SMALL POP IN THE FORECAST WITH VERY
LIGHT QPF. BUFKIT SOUNDINGS SHOW A GOOD DEAL OF MOISTURE BELOW
2000 FEET WITH THE LOW-LEVEL NORTHEAST FLOW...SO AGAIN EXPECT A
MOSTLY CLOUDY DAY ON SUNDAY WITH JUST OCCASIONAL PEAKS OF
SUNSHINE. THE BEST CHANCE OF GETTING SUNSHINE WOULD BE OVER THE
FAR SOUTHWESTERN COUNTIES WHERE SOME TEMPERATURES NEAR 80 WILL BE
POSSIBLE. OVER MUCH OF THE REMAINDER OF THE CWA...HIGHS WILL RANGE
FROM 65 TO ABOUT 72 DEGREES.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...BIG STORY THROUGH THE LONG TERM WILL BE THE DRY
AND VERY WARM CONDITIONS. THE BEGINNING OF THE WORK WEEK WILL
START OUT RATHER CLOUDY WITH TEMPS NEAR AVERAGE. STALLED FRONTAL
BOUNDARY WILL FINALLY LIFT NORTH AS SFC HIGH PRES MOVES OFFSHORE
AND UPR RIDGE BEGINS TO BUILD. CLOUDS SHOULD SCOUR OUT ESP ACROSS
SW AREAS BY AFTERNOON...AND ALLOW FOR TEMPS TO CLIMB INTO THE
MID/UPR 70S HERE. A BIT MORE CLOUDS WILL HOLD TEMPS NEAR 70 FOR NE
AREAS. TEMPS WILL BE MILD IN THE LOW 60S MON NIGHT.
SW FLOW INC ON TUE AND WITH PLENTY OF SUN TEMPS RISE INTO THE MID
80S. SOME INDICATION THAT SHORTWAVE ENERGY WILL MOVE THROUGH THE
MID ATLANTIC/VA...AND COULD SPELL A FEW AFTERNOON THUNDERSHOWERS
ACROSS NRN FA. LEFT IN SLIGHT CHANCE POPS TO ACCOUNT FOR THIS
POSSIBILITY. SREF AND 29/00Z ECM HOWEVER HAVE A MORE AMPLIFIED UPR
RIDGE AND KEEP ENTIRE AREA DRY.
TEMPS REALLY SKYROCKET WED INTO LATE IN THE WEEK...AS LOW LEVEL
THICKNESSES SOAR ABOVE 1400M. BOTH ECM AND GFS FCST MAX TEMPS IN
THE MID/UPR 80S. TEMPS IN ACTUALLITY MAY BE A BIT HIGHER...NEAR
90...AS MOS TRENDS TOWARDS CLIMO IN THE LONG RANGE. CHANCES FOR
PRECIP ARE NEARLY NON EXISTANT AS LARGE RIDGE WILL BE CENTERED
OVER E NC. EVEN SEA BREEZE ACTIVITY WILL BE VERY LIMITED DUE TO
THE SW COMPONENT SFC FLOW.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /06Z SUNDAY THROUGH 06Z MONDAY/
AS OF 130 AM SUNDAY...MVFR CIGS REDEVELOPING OVER MOST OF AREA AND
EXPECTED TO PERSIST THROUGH MOST OF DAY WITH ANOTHER SURGE OF LOW
LVL NE WINDS AS WEAK LOW PRES MOVES OFFSHORE. SCT SHOWERS FROM
CURRENT MCS ACTIVITY OVER OH VLY MAY CLIP NRN SECTIONS AROUND 12Z
BUT MAINLY NE OF TAF SITES. WITH TYPICAL LOWERING OF CIGS
OVERNIGHT...PERIOD OF IFR LIKELY MOST SITES 09Z-13Z...THEN RAISING
BACK TO MVFR FOR MID MORNING UNTIL LATE AFTN. PERIOD OF VFR FOR LATE
AFTN INTO EVENING...THEN MVFR REDEVELOPING.
LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 AM SUN...MAINLY VFR CONDITIONS THROUGH THE LONG TERM AS
HIGH PRES MOVES OFFSHORE AND CLOUDS SCOUR ON MON. COULD BE SOME
LINGERING MVFR MON MORNING BEFORE DOING SO HOWEVER. TUE THROUGH
THE END OF THE WEEK WILL BE MOSTLY SUNNY WITH SOME PATCHY BR
POSSIBLE EACH AND EVERY NIGHT AS DEWPOINTS CLIMB INTO THE LOWER
60S AND WINDS ARE LIGHT.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 1240 AM SUN...LATEST NAM AND RUC HAVE DECENT HANDLE ON CURRENT
WINDS AND USED THEM FOR UPDATE. WEAK LOW MOVING OFF NRN WATERS IS
PRODUCING NW TO N WINDS 15 KT OR LESS MOST OF AREA...WITH A BRIEF
N-NE SURGE EXPECTED TO DEVELOP OVER NRN WATERS TOWARD MORNING AS LOW
MOVES NE. ALSO ADJUSTED SEAS AS HEIGHTS STILL RUNNING 4-5 FEET OVER
NRN WATERS PER WAVERIDER BUOYS.
/PREVIOUS DISCUSSION/
AS OF 955 PM SATURDAY...COMPLICATED WIND DIRECTION FORECAST BUT
FORTUNATELY WIND SPEEDS ARE FORECAST TO BE 15 KT OR LESS THROUGH
SUNDAY. A WEAK WAVE OF LOW PRESSURE ALONG THE STATIONARY FRONT WAS
LOCATED OFF OF THE OUTER BANKS. THIS LOW IS FORECAST TO MOVE WELL
OFF THE COAT OVERNIGHT AND THE GUIDANCE IS IN AGREEMENT THAT THE
FRONT WILL LIFT NORTH ALONG THE COAST WITH THE FLOW SHIFTING FROM
EASTERLY TO SOUTHWEST OVERNIGHT WHILE INLAND A HYBRID DAMMING
PATTERN REMAINS. THE FRONT IS THEN FORECAST TO DRIFT BACK SOUTH
THROUGH ALL THE WATERS DURING THE DAY ON SUNDAY WITH THE FLOW
TURNING BACK TO THE NORTH AND NORTHEAST. SEAS ARE FORECAST TO BE
IN THE 2 TO 4 FOOT RANGE. NO SMALL CRAFT ADVISORIES ARE ANTICIPATED.
LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 330 AM SUN...SEAS AND WINDS MAINLY BELOW SCA RANGE THROUGH
THE PERIOD. WINDS WILL TRANSLATE FROM EAST TO SOUTH ON MON AS HIGH
PRES MOVES OFFSHORE. SW FLOW WILL THEN PERSIST FROM MON NIGHT
THROUGH THE END OF THE WEEK AS UPR RIDGE BUILDS IN WITH SFC HIGH
ANCHORED OFFSHORE. WINDS MAY APPROACH SCA BRIEFLY FOR THE OUTER
WATERS TUE AFTERNOON AND EVENING AS A SHORTWAVE PASSES BY TO THE
NORTH.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC/JME
NEAR TERM...CTC/JME/LEP
SHORT TERM...CTC
LONG TERM...TL
AVIATION...CTC/JME/TL
MARINE...CTC/JME/TL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
313 AM EDT SUN APR 29 2012
.SYNOPSIS...
HIGH PRESSURE OVER EASTERN GREAT LAKES AND NEW ENGLAND WILL MOVE
OFFSHORE TODAY....ALLOWING A NEARLY STATIONARY FRONT OVER SOUTH
CAROLINA TO RETURN NORTH AS A WARM FRONT. A COLD FRONT WILL MOVE
BACK SOUTH ACROSS NORTH CAROLINA THIS AFTERNOON AND EVENING.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 305 AM SUNDAY...
MOSTLY A TEMPERATURE FORECAST TODAY...AND WITH LOW FORECASTER
CONFIDENCE BASED ON UNCERTAINTY IN THE EROSION OF THE WIDESPREAD
STRATUS AND POOR MODEL PERFORMANCE WITH THE RESIDUAL WEDGE AIRMASS
OVER THE AREA. THE WEDGE BOUNDARY REMAINS STATIONARY OVER SC THIS
MORNING...WITH HIGH PRESSURE OVER EASTERN CANADA BEGINNING TO NOSE
SOUTH ACROSS THE GREAT LAKES TOWARD THE OUR AREA. THE STRATUS
LAYER CONTINUES BE RATHER THIN...ONLY A FEW HUNDRED FEET
DEEP...BUT THERE HAS BEEN NO SIGNIFICANT MECHANISM TO HELP ERODE
THE CLOUDS. MODELS MAY ONCE AGAIN BE TOO AGGRESSIVE IN SHOWING
SOUTHWESTERLY LOW LEVEL FLOW DEVELOPING THIS MORNING...WHICH WOULD
LEAD TO FASTER SCATTERING OF CLOUD BY MID-MORNING. FORECAST
1000-850MB THICKNESSES RANGE FROM 1360M IN THE NORTHEAST TO NEAR
1400M IN THE SOUTHWEST. 1400M WOULD SUPPORT HIGHS IN THE MID 80S IN
THE SOUTHWEST UNDER FULL SUN...AND THE MAV GUIDANCE EVEN HAS
VALUES AS HIGH AS 88 OVER THE SOUTHERN PIEDMONT. HOWEVER...GIVEN
THAT THE NAM/GFS HAVE STRUGGLED SO MUCH WITH THIS WEDGE AIRMASS
OVER THE PAST 24 HOURS...AND ALSO THAT RECENT HRRR RUNS SHOW
STRATUS LINGERING THROUGH LATER MORNING...CONFIDENCE IS JUST NOT
HIGH ENOUGH TO FORECAST MID 80S IN THE SOUTHWEST. WE WILL KEEP
FORECAST HIGHS IN THE UPPER 60S IN THE NORTHEAST WHERE STRATUS
WILL LINGER THROUGH MUCH OF THE DAY...TO AROUND 80 IN THE
SOUTHWEST.
IF THE CLOUDS DO BREAK BY MIDDAY AND LOW TO MID 80S CAN BE
REACHED...STEEP MID LEVEL LAPSE RATES AROUND 7-7.5 C/KM WOULD HELP
TO SUPPORT 500-1000 J/KG OF MLCAPE SOUTHERN PIEDMONT.B
HOWEVER...FORECAST SOUNDINGS ALSO SHOW A DECENT CAP JUST ABOVE
800MB. THE MID LEVEL RIDGE AXIS THAT IS CURRENTLY WEST OF THE
MOUNTAINS WILL BE INCHING EASTWARD...AND LOW LEVEL FORCING WILL BE
WEAK TO NON-EXISTENT...SO WE WILL LEAVE THE FORECAST DRY FOR TODAY.
TONIGHT...SURFACE HIGH PRESSURE WILL BUILD OVER THE GREAT LAKES AND
EXTEND SOUTHEAST INTO VA AND NC. THIS WILL HELP SUPPLY ANOTHER SHOT
OF COOL AND MOIST NORTHEASTERLY LOW LEVEL FLOW...WITH STRATUS LIKELY
TO SURGE BACK IN ACROSS THE AREA. WITH THE MID LEVEL RIDGE BUILDING
OVERHEAD AND INCREASING MOISTURE BELOW THE SUBSIDENCE
INVERSION...FORECAST SOUNDINGS SHOW QUITE A BIT OF VEERING LOW
LEVEL WINDS AND WARM ADVECTION OVERNIGHT...WHICH MAY LEAD TO PATCHY
LIGHT RAIN AND/OR DRIZZLE. LOWS IN THE MID 50S NORTHEAST TO AROUND
60 SOUTHWEST.
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM...
HIGH PRESSURE SURFACE AND ALOFT LOCATED TO OUR SOUTH AT SUNRISE
TUESDAY. A SUBTLE SHORT WAVE IS SURPRISINGLY DEPICTED CONSISTENTLY
ACROSS SEVERAL MODELS FOR THE MID ATLANTIC REGION DURING THE DAY...
INDUCING WEAK SURFACE TROUGHING OVER VIRGINIA AND NORTH CAROLINA.
LOW LEVEL CONVERGENCE IS QUITE WEAK BUT AFTERNOON INSTABILITY...
CAPE AND MID LEVEL TEMPERATURE LAPSE RATES ALL INDICATE CONVECTION
IS A POSSIBILITY. WITH SUCH WEAK FORCING... WILL KEEP CHANCES FOR
THUNDER AT SLIGHT AND IN THE AFTERNOON.
MODEL CONSENSUS ON 1000 TO 850 MILLIBAR THICKNESS TUESDAY AFTERNOON
IN LINE WITH CLIMATOLOGICAL NORMALS FOR EARLY JUNE. CIRRUS CLOUDS
COULD IMPACT AFTERNOON TEMPERATURES... BUT FOR NOW WILL MINIMALIZE
THIS AND FORECAST HIGH TEMPERATURES IN THE LOWER 80S NORTHWEST AND
MID 80S ELSEWHERE.
ANY AFTERNOON CONVECTION SHOULD NOT PERSIST PAST LATE EVENING
TUESDAY NIGHT. LOW LEVEL THICKNESSES MORE TYPICAL OF EARLY JUNE
PERSIST. PRECIPITABLE WATERS IN EXCESS OF 1.25 INCHES AND A LIGHT
SOUTHWEST BREEZE WITH PERIODS OF CALM WILL ALLOW TEMPERATURES TO
FALL NO LOWER THAN THE LOWER 60S BY SUNRISE WEDNESDAY.
LOW LEVEL THICKNESSES RISE FIVE TO TEN METERS WEDNESDAY AFTERNOON
OVER THE PREVIOUS DAY AND MIXING HEIGHTS WILL PERHAPS REACH 7000
FEET. MOISTURE IS SOMEWHAT LIMITED... ESPECIALLY TO THE SOUTH. A
WEAK BOUNDARY LOCATED NEAR OR NORTH OF HIGHWAY 64 WILL POTENTIALLY
BE A FOCUS FOR CONVECTION. DUE TO LIMITED MOISTURE WILL KEEP CHANCES
AT SLIGHT FOR MID TO LATE AFTERNOON. DAMAGING DOWNBURST WINDS WILL
BE A RISK DUE TO EVAPORATIVELY COOLED DOWNDRAFTS IF THE ABOVE
SCENARIO HOLDS UP... BUT WITH COVERAGE LIMITED TO ABSENT... NO PLANS
TO MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. AFTERNOON
THICKNESSES MORE TYPICAL OF MID JULY ARE FORECAST. HIGH TEMPERATURES
MOSTLY MID 80S.
IN SPITE OF THE BOUNDARY IN THE NORTH... ANY CONVECTION LOOKS TO BE
SHORT LIVED ONCE THE HEATING OF THE DAY IS LOST. LOW TEMPERATURES
SHOULD FALL NO LOWER THAN THE LOW TO MID 60S AS 1000 TO 850 MILLIBAR
THICKNESSES REMAIN ABOVE 1400 METERS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 AM...
THE AIR MASS DRYS A BIT THURSDAY IN LIGHT WEST FLOW AS THE UPPER
LEVEL RIDGE OVER THE EASTERN UNITED STATES STRENGTHENS SLIGHTLY.
LATE AFTERNOON CONVECTION NOT IMPOSSIBLE BUT CHANCES LOOK LESS THAN
SLIGHT AT THIS TIME... WITH THE SCENARIO REPEATING FOR FRIDAY AS
WELL. CONTINUE TO FAVOR THE MORE PERSISTENT RIDGE OF THE ECMWF MODEL
THOUGH THE ECMWF DOES RETROGRADE THE RIDGE TO THE MIDWEST THURSDAY
NIGHT AND INTO THE WEEKEND. THIS SHOULD ALLOW AFTERNOON TEMPERATURES
TO SLIP A BIT SATURDAY AND INCREASE AFTERNOON RAIN CHANCES FOR
SATURDAY AFTERNOON.
WELL ABOVE NORMAL TEMPERATURES TO CONTINUE FOR THIS FORECAST PERIOD.
MID TO UPPER 80S THURSDAY AND FRIDAY... LOW TO MID 80S SATURDAY. LOW
TEMPERATURES IN THE LOW TO MID 60S.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
AS OF 145 AM SUNDAY...
MVFR CEILINGS ARE PREDOMINATE ACROSS ALL OF CENTRAL NC THIS MORNING
AS LOW LEVEL MOISTURE REMAIN LOCKED IN PLACE NORTH OF STATIONARY
FRONT OVER SC. THESE CEILINGS SHOULD PERSIST THROUGH 12Z...AFTER
WHICH MODELS INDICATE THE LAYER OF LOW LEVEL MOISTURE WILL BEGIN TO
ERODE WITH WESTERLY LOW TO MID LEVEL FLOW. MODELS MAY BE ERODING
STRATUS FROM THE SOUTH AND WEST TOO QUICKLY...SO MVFR CEILINGS MAY
PERSIST UNTIL LATE MORNING AT KGSO AND KINT...AND ARE MORE LIKELY TO
PERSIST WELL INTO THE AFTERNOON FROM KRDU TO KRWI. WINDS WILL
GENERALLY BE LIGHT AND VARIABLE FOR A GOOD PORTION OF THE DAY BUT
WILL BECOME EAST-NORTHEASTERLY AGAIN THIS EVENING AS HIGH PRESSURE
OVER THE GREAT LAKES PUSHES ANOTHER COLD FRONT INTO THE AREA FROM
THE NORTH. THIS COOL STABLE FLOW WILL BRING STRATUS BACK ACROSS THE
AREA ONCE AGAIN TONIGHT AND MONDAY MORNING...POTENTIALLY WITH PATCHY
LIGHT RAIN AT TIMES. -SMITH
OUTLOOK...
THE AIR MASS WILL GRADUALLY DRY OUT ACROSS CENTRAL NC MONDAY INTO
TUESDAY AS HIGH PRESSURE AT THE SURFACE AND ALOFT SETTLES OVERHEAD.
THIS SHOULD LEAD TO SHORTER PERIODS OF MVFR CEILINGS (MAINLY
OCCURRING OVERNIGHT INTO THE MORNING HOURS). VFR CONDITIONS
ANTICIPATED FOR MOST OF WEDNESDAY AND THURSDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/99
LONG TERM...99
AVIATION...SMITH/WSS
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
155 AM EDT SUN APR 29 2012
.SYNOPSIS...
A STATIONARY FRONT OVER SOUTH CAROLINA WILL MOVE BRIEFLY NORTH
ALONG THE COAST AS A WARM FRONT TONIGHT BEFORE MOVING BACK SOUTH
AS A COLD FRONT ON SUNDAY AND SUNDAY NIGHT. THE FRONT SHOULD
DISSIPATE SOUTH OF THE AREA MONDAY AS HIGH PRESSURE BUILDS IN FROM
THE EAST TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1240 AM SUN...UPDATED FOR CURRENT PT CLDY SKIES OVER SRN HALF
OF AREA...AND DROPPED POPS UNTIL AFTER 2 A FOR NRN SECTIONS. ALSO
LOWERED MIN TEMPS BASEDO ON CURRENT OBS AS EVENING CLEARING ALLOWED
MORE COOLING.
/PREVIOUS DISCUSSION/
AS OF 955 PM SATURDAY...THE LOW CLOUDS HAVE DISSIPATED MUCH FASTER
AND OVER A MORE WIDESPREAD AREA THAN PREVIOUSLY EXPECTED THIS
EVENING. PERHAPS THIS IS DUE IN PART TO SUBSIDENCE SEEN IN THE OMEGA
FORECASTS AS A WEAK LOW MOVES AWAY FROM THE NC COAST. BOTH THE 00Z
GSO AND MHX SOUNDINGS WERE DEEPLY SATURATED IN THE LOW
LEVELS...EXHIBITED SHARP LOW LEVEL INVERSIONS...AND LOW LEVEL
EASTERLY FLOW...ALL SUGGESTIVE OF CONDITIONS FAVORABLE FOR LOW CLOUD
REDEVELOPMENT LATER TONIGHT. THE 18Z NAM-12 FORECAST SOUNDINGS STILL
SUPPORTED LOW CLOUDS BUT WITH SHALLOWER LOW LEVEL MOISTURE. GIVEN A
SURFACE PATTERN INDICATIVE OF HYBRID DAMMING AND THE ABOVE FACTORS I
AM STILL EXPECTING WIDESPREAD LOW CLOUDS BUT NOT WITH AS MUCH
CONFIDENCE AS BEFORE. REMNANT SHOWERS FROM AN UPSTREAM MCS COULD
AFFECT THE NORTHERN PORTION OF THE AREA LATE SO WILL MAINTAIN 20-30%
POPS NORTH FOR LATE TONIGHT.
THE STATIONARY BOUNDARY CURRENTLY LOCATED FROM NORTHEAST SOUTH
CAROLINA INTO EXTREME SOUTHEAST NORTH CAROLINA IS STILL EXPECTED
TO LIFT NORTH OVERNIGHT...MAINLY ALONG THE IMMEDIATE COAST. THIS
WILL RESULT IN THE FLOW TURNING FROM EASTERLY TO SOUTHWEST ALONG
AND NEAR THE COAST. FURTHER INLAND A HYBRID DAMMING PATTERN WILL
REMAIN AND RETARD THE NORTHWARD MOVEMENT OF THE RETREATING
BOUNDARY WITH NORTHERLY FLOW PERSISTING. STILL EXPECTING LOW
TEMPERATURES 53 TO 58 INLAND WITH TEMPERATURES BRIEFLY RISING
ALONG THE COAST SHOULD THE SW FLOW MATERIALIZE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
AS OF 245 PM SATURDAY...THE COLD FRONT WILL DRIVE TO THE SOUTH OF
THE AREA AGAIN ON SUNDAY WITH THE NAM12 AND GFS SHOWING A BROKEN
BAND OF MOISTURE AND AGAIN A SMALL POP IN THE FORECAST WITH VERY
LIGHT QPF. BUFKIT SOUNDINGS SHOW A GOOD DEAL OF MOISTURE BELOW
2000 FEET WITH THE LOW-LEVEL NORTHEAST FLOW...SO AGAIN EXPECT A
MOSTLY CLOUDY DAY ON SUNDAY WITH JUST OCCASIONAL PEAKS OF
SUNSHINE. THE BEST CHANCE OF GETTING SUNSHINE WOULD BE OVER THE
FAR SOUTHWESTERN COUNTIES WHERE SOME TEMPERATURES NEAR 80 WILL BE
POSSIBLE. OVER MUCH OF THE REMAINDER OF THE CWA...HIGHS WILL RANGE
FROM 65 TO ABOUT 72 DEGREES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM SAT...NE SFC FLOW WILL CONT ACROSS THE AREA THROUGH
TUE AFTN WITH LOW CLOUDS PERSISTING AREAWIDE. EXPECT LOW TO MID
50S FOR LOWS SUNDAY NIGHT WITH A 10 DEGREE TEMP RANGE ACROSS THE
CWA ON MON WITH HIGHS FROM THE MID 60S NERN AREAS TO THE MID 70S
SW. WINDS BECOME SOUTHERLY LATE IN THE AFTERNOON ON AS SFC HIGH
PRES RIDGES IN TO THE SOUTH ERODING LOW CLOUDS ALLOWING TEMPS TO
CLIMB INTO THE THE LWR 80S ACRS INLAND AREAS. MDT INSTABILITY AND
AMPLE AMS MSTR WILL BE IN PLACE FOR ISOLATED CONVECTION ACROSS
MUCH OF THE AREA.
H5 RIDGE BUILDS ACROSS ERN NC FOR THE REMAINDER OF THE WEEK WITH
DAYTIME TEMPS CLIMBING THROUGH THE 80S BY THE END OF THE WEEK AND
NIL POPS EXPECTED. MIN TEMPS WILL BE MILD WITH LOW IN THE LWR TO MID
60S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /06Z SUNDAY THROUGH 06Z MONDAY/
AS OF 130 AM SUNDAY...MVFR CIGS REDEVELOPING OVER MOST OF AREA AND
EXPECTED TO PERSIST THROUGH MOST OF DAY WITH ANOTHER SURGE OF LOW
LVL NE WINDS AS WEAK LOW PRES MOVES OFFSHORE. SCT SHOWERS FROM
CURRENT MCS ACTIVITY OVER OH VLY MAY CLIP NRN SECTIONS AROUND 12Z
BUT MAINLY NE OF TAF SITES. WITH TYPICAL LOWERING OF CIGS
OVERNIGHT...PERIOD OF IFR LIKELY MOST SITES 09Z-13Z...THEN RAISING
BACK TO MVFR FOR MID MORNING UNTIL LATE AFTN. PERIOD OF VFR FOR LATE
AFTN INTO EVENING...THEN MVFR REDEVELOPING.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 300 PM SAT...LOW CLOUDS CONTINUE WITH N TO NE FLOW THROUGH
MON. WINDS START TO VEER TO ONSHORE MON NIGHT BECOMING SWLY TUE
AFTN ERODING THE IFR CIGS WITH MOSTLY SUNNY SKIES EXPECTED FOR TUE
AFTN WITH ISOLD CONVECTION POSSIBLE. SW FLOW CONTINUES THROUGH THE
REMAINDER OF THE WEEK WITH VFR CONDS EXPECTED.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 1240 AM SUN...LATEST NAM AND RUC HAVE DECENT HANDLE ON CURRENT
WINDS AND USED THEM FOR UPDATE. WEAK LOW MOVING OFF NRN WATERS IS
PRODUCING NW TO N WINDS 15 KT OR LESS MOST OF AREA...WITH A BRIEF
N-NE SURGE EXPECTED TO DEVELOP OVER NRN WATERS TOWARD MORNING AS LOW
MOVES NE. ALSO ADJUSTED SEAS AS HEIGHTS STILL RUNNING 4-5 FEET OVER
NRN WATERS PER WAVERIDER BUOYS.
/PREVIOUS DISCUSSION/
AS OF 955 PM SATURDAY...COMPLICATED WIND DIRECTION FORECAST BUT
FORTUNATELY WIND SPEEDS ARE FORECAST TO BE 15 KT OR LESS THROUGH
SUNDAY. A WEAK WAVE OF LOW PRESSURE ALONG THE STATIONARY FRONT WAS
LOCATED OFF OF THE OUTER BANKS. THIS LOW IS FORECAST TO MOVE WELL
OFF THE COAT OVERNIGHT AND THE GUIDANCE IS IN AGREEMENT THAT THE
FRONT WILL LIFT NORTH ALONG THE COAST WITH THE FLOW SHIFTING FROM
EASTERLY TO SOUTHWEST OVERNIGHT WHILE INLAND A HYBRID DAMMING
PATTERN REMAINS. THE FRONT IS THEN FORECAST TO DRIFT BACK SOUTH
THROUGH ALL THE WATERS DURING THE DAY ON SUNDAY WITH THE FLOW
TURNING BACK TO THE NORTH AND NORTHEAST. SEAS ARE FORECAST TO BE
IN THE 2 TO 4 FOOT RANGE. NO SMALL CRAFT ADVISORIES ARE ANTICIPATED.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 300 PM SAT...DO NOT ANTICIPATE SCA CONDITIONS IN THE LONG
TERM. NE WINDS IN THE 10 TO 15 KT RANGE AND SEAS OF 2 TO 4 FEET
WITH 5 FT SEAS FOR THE OUTER COASTAL WATERS EXPECTED THROUGH MON.
WINDS VEER TO SE MON NIGHT AND BECOME SW TUE CONTG THROUGH THE
REMAINDER OF THE WEEK WITH SEAS MAINLY IN THE 2-4 FT RANGE. MAY
SEE SOME NOCTURNAL WINDS WS AROUND 15 KT WITH SEAS 5 FT FOR THE
OUTER SRN AND CNTRL COASTAL WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC/JME
NEAR TERM...JBM/JME
SHORT TERM...CTC
LONG TERM...JAC
AVIATION...JBM/JAC
MARINE...JBM/JME/JAC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1250 AM EDT SUN APR 29 2012
.SYNOPSIS...
A STATIONARY FRONT OVER SOUTH CAROLINA WILL MOVE BRIEFLY NORTH
ALONG THE COAST AS A WARM FRONT TONIGHT BEFORE MOVING BACK SOUTH
AS A COLD FRONT ON SUNDAY AND SUNDAY NIGHT. THE FRONT SHOULD
DISSIPATE SOUTH OF THE AREA MONDAY AS HIGH PRESSURE BUILDS IN FROM
THE EAST TUESDAY INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 1240 AM SUN...UPDATED FOR CURRENT PT CLDY SKIES OVER SRN HALF
OF AREA...AND DROPPED POPS UNTIL AFTER 2 A FOR NRN SECTIONS. ALSO
LOWERED MIN TEMPS BASEDO ON CURRENT OBS AS EVENING CLEARING ALLOWED
MORE COOLING.
/PREVIOUS DISCUSSION/
AS OF 955 PM SATURDAY...THE LOW CLOUDS HAVE DISSIPATED MUCH FASTER
AND OVER A MORE WIDESPREAD AREA THAN PREVIOUSLY EXPECTED THIS
EVENING. PERHAPS THIS IS DUE IN PART TO SUBSIDENCE SEEN IN THE OMEGA
FORECASTS AS A WEAK LOW MOVES AWAY FROM THE NC COAST. BOTH THE 00Z
GSO AND MHX SOUNDINGS WERE DEEPLY SATURATED IN THE LOW
LEVELS...EXHIBITED SHARP LOW LEVEL INVERSIONS...AND LOW LEVEL
EASTERLY FLOW...ALL SUGGESTIVE OF CONDITIONS FAVORABLE FOR LOW CLOUD
REDEVELOPMENT LATER TONIGHT. THE 18Z NAM-12 FORECAST SOUNDINGS STILL
SUPPORTED LOW CLOUDS BUT WITH SHALLOWER LOW LEVEL MOISTURE. GIVEN A
SURFACE PATTERN INDICATIVE OF HYBRID DAMMING AND THE ABOVE FACTORS I
AM STILL EXPECTING WIDESPREAD LOW CLOUDS BUT NOT WITH AS MUCH
CONFIDENCE AS BEFORE. REMNANT SHOWERS FROM AN UPSTREAM MCS COULD
AFFECT THE NORTHERN PORTION OF THE AREA LATE SO WILL MAINTAIN 20-30%
POPS NORTH FOR LATE TONIGHT.
THE STATIONARY BOUNDARY CURRENTLY LOCATED FROM NORTHEAST SOUTH
CAROLINA INTO EXTREME SOUTHEAST NORTH CAROLINA IS STILL EXPECTED
TO LIFT NORTH OVERNIGHT...MAINLY ALONG THE IMMEDIATE COAST. THIS
WILL RESULT IN THE FLOW TURNING FROM EASTERLY TO SOUTHWEST ALONG
AND NEAR THE COAST. FURTHER INLAND A HYBRID DAMMING PATTERN WILL
REMAIN AND RETARD THE NORTHWARD MOVEMENT OF THE RETREATING
BOUNDARY WITH NORTHERLY FLOW PERSISTING. STILL EXPECTING LOW
TEMPERATURES 53 TO 58 INLAND WITH TEMPERATURES BRIEFLY RISING
ALONG THE COAST SHOULD THE SW FLOW MATERIALIZE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
AS OF 245 PM SATURDAY...THE COLD FRONT WILL DRIVE TO THE SOUTH OF
THE AREA AGAIN ON SUNDAY WITH THE NAM12 AND GFS SHOWING A BROKEN
BAND OF MOISTURE AND AGAIN A SMALL POP IN THE FORECAST WITH VERY
LIGHT QPF. BUFKIT SOUNDINGS SHOW A GOOD DEAL OF MOISTURE BELOW
2000 FEET WITH THE LOW-LEVEL NORTHEAST FLOW...SO AGAIN EXPECT A
MOSTLY CLOUDY DAY ON SUNDAY WITH JUST OCCASIONAL PEAKS OF
SUNSHINE. THE BEST CHANCE OF GETTING SUNSHINE WOULD BE OVER THE
FAR SOUTHWESTERN COUNTIES WHERE SOME TEMPERATURES NEAR 80 WILL BE
POSSIBLE. OVER MUCH OF THE REMAINDER OF THE CWA...HIGHS WILL RANGE
FROM 65 TO ABOUT 72 DEGREES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM SAT...NE SFC FLOW WILL CONT ACROSS THE AREA THROUGH
TUE AFTN WITH LOW CLOUDS PERSISTING AREAWIDE. EXPECT LOW TO MID
50S FOR LOWS SUNDAY NIGHT WITH A 10 DEGREE TEMP RANGE ACROSS THE
CWA ON MON WITH HIGHS FROM THE MID 60S NERN AREAS TO THE MID 70S
SW. WINDS BECOME SOUTHERLY LATE IN THE AFTERNOON ON AS SFC HIGH
PRES RIDGES IN TO THE SOUTH ERODING LOW CLOUDS ALLOWING TEMPS TO
CLIMB INTO THE THE LWR 80S ACRS INLAND AREAS. MDT INSTABILITY AND
AMPLE AMS MSTR WILL BE IN PLACE FOR ISOLATED CONVECTION ACROSS
MUCH OF THE AREA.
H5 RIDGE BUILDS ACROSS ERN NC FOR THE REMAINDER OF THE WEEK WITH
DAYTIME TEMPS CLIMBING THROUGH THE 80S BY THE END OF THE WEEK AND
NIL POPS EXPECTED. MIN TEMPS WILL BE MILD WITH LOW IN THE LWR TO MID
60S.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /TONIGHT AND SUNDAY/...
AS OF 715 PM SATURDAY...SOME BREAKS IN THE CLOUDS WILL OCCUR AT
THE TAF SITES THIS EVENING AND EXPECT CEILINGS TO VARY FROM VFR TO
MVFR. LATER TONIGHT WIDESPREAD MVFR CEILINGS WILL REDEVELOP AND
NOW WILL BE FORECAST TO LOWER TO IFR LEVELS BASED ON TRENDS IN THE
LATEST AVIATION GUIDANCE AND EXPECTED HYBRID DAMMING SURFACE
PATTERN INLAND. THE GFS/LAMP WERE FASTER TO INDICATE THIS LOWERING
THAN THE NAM AND WILL LEAN TOWARD THE GFS WITH IFR CONDITIONS
FORECAST TO DEVELOP 06Z-08Z. CEILINGS ARE THEN EXPECTED TO RISE TO
MVFR BY SUNDAY MORNING AND AT LEAST TEMPORARILY TO VFR MID SUNDAY
AFTERNOON BUT COULD LOWER TO MVFR OR WORSE SUNDAY EVENING AS THE
FRONT MOVES SOUTH OF THE AREA YET AGAIN.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 300 PM SAT...LOW CLOUDS CONTINUE WITH N TO NE FLOW THROUGH
MON. WINDS START TO VEER TO ONSHORE MON NIGHT BECOMING SWLY TUE
AFTN ERODING THE IFR CIGS WITH MOSTLY SUNNY SKIES EXPECTED FOR TUE
AFTN WITH ISOLD CONVECTION POSSIBLE. SW FLOW CONTINUES THROUGH THE
REMAINDER OF THE WEEK WITH VFR CONDS EXPECTED.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 1240 AM SUN...LATEST NAM AND RUC HAVE DECENT HANDLE ON CURRENT
WINDS AND USED THEM FOR UPDATE. WEAK LOW MOVING OFF NRN WATERS IS
PRODUCING NW TO N WINDS 15 KT OR LESS MOST OF AREA...WITH A BRIEF
N-NE SURGE EXPECTED TO DEVELOP OVER NRN WATERS TOWARD MORNING AS LOW
MOVES NE. ALSO ADJUSTED SEAS AS HEIGHTS STILL RUNNING 4-5 FEET OVER
NRN WATERS PER WAVERIDER BUOYS.
/PREVIOUS DISCUSSION/
AS OF 955 PM SATURDAY...COMPLICATED WIND DIRECTION FORECAST BUT
FORTUNATELY WIND SPEEDS ARE FORECAST TO BE 15 KT OR LESS THROUGH
SUNDAY. A WEAK WAVE OF LOW PRESSURE ALONG THE STATIONARY FRONT WAS
LOCATED OFF OF THE OUTER BANKS. THIS LOW IS FORECAST TO MOVE WELL
OFF THE COAT OVERNIGHT AND THE GUIDANCE IS IN AGREEMENT THAT THE
FRONT WILL LIFT NORTH ALONG THE COAST WITH THE FLOW SHIFTING FROM
EASTERLY TO SOUTHWEST OVERNIGHT WHILE INLAND A HYBRID DAMMING
PATTERN REMAINS. THE FRONT IS THEN FORECAST TO DRIFT BACK SOUTH
THROUGH ALL THE WATERS DURING THE DAY ON SUNDAY WITH THE FLOW
TURNING BACK TO THE NORTH AND NORTHEAST. SEAS ARE FORECAST TO BE
IN THE 2 TO 4 FOOT RANGE. NO SMALL CRAFT ADVISORIES ARE ANTICIPATED.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 300 PM SAT...DO NOT ANTICIPATE SCA CONDITIONS IN THE LONG
TERM. NE WINDS IN THE 10 TO 15 KT RANGE AND SEAS OF 2 TO 4 FEET
WITH 5 FT SEAS FOR THE OUTER COASTAL WATERS EXPECTED THROUGH MON.
WINDS VEER TO SE MON NIGHT AND BECOME SW TUE CONTG THROUGH THE
REMAINDER OF THE WEEK WITH SEAS MAINLY IN THE 2-4 FT RANGE. MAY
SEE SOME NOCTURNAL WINDS WS AROUND 15 KT WITH SEAS 5 FT FOR THE
OUTER SRN AND CNTRL COASTAL WATERS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC/JME
NEAR TERM...JBM/JME
SHORT TERM...CTC
LONG TERM...JAC
AVIATION...JAC/CTC/JME
MARINE...JBM/JME/JAC
AREA FORECAST DISCUSSION
NWS TULSA OK
1206 AM CDT SUN APR 29 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED CONVECTION HAS DEVELOPED OVER WESTERN AND CENTRAL
OKLAHOMA TONIGHT ALONG AND NORTH OF A FRONTAL BOUNDARY POSITIONED
OVER THE REGION. THIS CONVECTION WILL HAVE THE GREATEST CHANCES OF
AFFECTING NORTHEAST OKLAHOMA TAF SITES. FRONTAL BOUNDARY IS
EXPECTED TO RETREAT NORTHWARD LATE OVERNIGHT AND SUNDAY...WHICH
WILL SHIFT WINDS OUT OF THE SOUTH AT ALL SITES. VFR CONDITIONS
WILL CONTINUE FOR NORTHEAST OKLAHOMA...WITH MVFR CONDITIONS WITHIN
ANY CONVECTIVE DEVELOP AND THEN RETURNING BACK TO VFR CONDITIONS
SUNDAY AFTERNOON/EVENING. FOR SOUTHEAST OKLAHOMA AND NORTHWEST
ARKANSAS...WILL LEAVE VFR CONDITIONS IN THE TAF...THOUGH SOME
EARLY MORNING MVFR CEILINGS COULD BE POSSIBLE.
&&
.PREV DISCUSSION... /ISSUED 727 PM CDT SAT APR 28 2012/
DISCUSSION...
LONG RANGE RADAR ECHOES FROM KINX ARE SHOWING HINTS THAT CONVECTION
IS TRYING TO DEVELOP TO THE SW OF OKC. MODEL SOUNDINGS SHOW THE
CAP WEAKENING AROUND AND AFTER 00Z...AND THIS WILL ALLOW FOR MORE
STORM DEVELOPMENT ALONG AND NORTH OF THE FRONT. THE LLJ IS
FORECAST TO STRENGTHEN TO THE SOUTH OF THE FRONT DURING THE
OVERNIGHT...ESPECIALLY OVER SW AND CNTRL OK. AS A RESULT...A
GRADUAL EXPANSION IN CONVECTIVE COVERAGE IS EXPECTED ACROSS N
CNTRL OK LATER THIS EVENING...WITH THIS ACTIVITY SPREADING
GENERALLY E/NE INTO NORTHEAST OK AROUND OR AFTER MIDNIGHT PER THE
MOST RECENT RUNS OF THE HRRR. THE ECMWF AND GFS ENSEMBLE DATA ALSO
SUPPORT THIS AS WELL. I HAVE RAISED POPS BASICALLY FROM THE I-44
CORRIDOR NORTHWARD INTO THE LIKELY CATEGORY. THE HRRR DOES ALSO
HINT THAT ONE OR TWO STORMS COULD REMAIN DISCRETE ON THE SOUTHERN
FRINGE OF THE CONVECTIVE CLUSTER...AND ANY POTENTIAL RIGHT MOVING
SUPERCELL WOULD MOVE MORE EAST THAN NORTH...AND COULD POTENTIALLY
AFFECT THE TULSA METRO AND SURROUNDING AREAS LATER. ANY RIGHT
MOVING SUPERCELL WOULD HAVE AT LEAST LIMITED TORNADO POTENTIAL
GIVEN THE STRENGTHENING 0-1KM SHEAR AND LOW LCLS TONIGHT. UPDATED
TEXT PRODUCTS OUT SHORTLY.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 65 78 65 80 / 60 50 70 50
FSM 65 84 64 81 / 20 20 30 50
MLC 64 79 66 80 / 20 20 30 30
BVO 61 77 63 79 / 70 60 70 50
FYV 60 80 61 77 / 40 20 40 60
BYV 62 80 61 77 / 30 30 40 60
MKO 63 80 64 79 / 40 30 50 40
MIO 64 79 64 80 / 60 50 70 50
F10 64 78 66 79 / 40 30 50 30
HHW 63 81 65 81 / 10 10 20 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...20
AREA FORECAST DISCUSSION
NWS MEDFORD OR
915 PM PDT SAT APR 28 2012
.UPDATE...
UPDATES WERE MADE TO THE WIND FORECAST OVER THE COASTAL WATERS FOR
THIS EVENING THROUGH TOMORROW BECAUSE OBSERVED WINDS HAVE
INCREASED ABOVE MODEL GUIDANCE ACROSS THE SOUTHERN WATERS. USED
THE RTMA AND THE RUC SHORT TERM MODELS CALIBRATED OFF OF OBSERVED
VALUES AT BUOY 27 TO UPDATE THE WIND FORECAST. SINCE AN UPDATE WAS
NEEDED FOR THE WINDS ALSO MADE SOME VERY MINOR ADJUSTMENTS TO THE
SKY COVER FOR TOMORROW MORNING TO DECREASE IT SLIGHTLY FROM ABOUT
TALENT SOUTHEASTWARD TO THE TULELAKE BASIN AND SHASTA VALLEY
AREAS. THE NET AFFECT WAS ONLY TO ADJUST THE SKY BY ONE CATEGORY.
BTL
&&
.DISCUSSION...
HIGH PRESSURE BUILDING OFFSHORE AND INDUCED LEE SIDE LOW PRESSURE
DEEPENING OVER CALIFORNIA HAS LED TO RAPIDLY INCREASING NORTH WINDS
IN THE SOUTHERN COASTAL WATERS THIS EVENING. THIS IS THE FIRST NORTH
WIND EVENT IN AWHILE IN THE WATERS AND SHOULD RESULT IN SOME
BENEFICIAL UPWELLING ALONG AND THE NEAR THE COAST. NORTH WINDS WILL
REMAIN MODERATE AND GUSTY IN THE SOUTHERN WATERS INTO SUNDAY
AFTERNOON, DIMINISHING IN THE EVENING AS THE OFFSHORE HIGH GETS
BUMPED INLAND BY AN APPROACHING LOW PRESSURE SYSTEM OFFSHORE.
CLOUDS ON THE WEST SIDE TONIGHT THROUGH SUNDAY MORNING WILL SERVE
TO KEEP TEMPERATURES UP TONIGHT, GIVING WARMING A HEAD START FOR
SUNDAY AFTERNOON. EXPECT TEMPERATURES TO BE 3 TO 8 DEGREES ABOVE
NORMAL FOR HIGHS SUNDAY AFTERNOON WITH PLENTY OF 60S AND 70S AND
EVEN A FEW 80S ACROSS THE AREA.
A FRONTAL SYSTEM WILL PUSH GENERALLY LIGHT PRECIPITATION ACROSS
THE MOUNTAINS AND WEST SIDE MONDAY INTO TUESDAY, WITH THE GREATEST
AMOUNTS ALONG THE COAST AND IN THE UMPQUA BASIN. TEMPERATURES WILL
BE KNOCKED DOWN TO NEAR NORMAL VALUES MONDAY THROUGH WEDNESDAY FROM
THIS FRONTAL SYSTEM.
MODELS HAVE TRENDED TOWARD A SOMEWHAT STRONGER FRONTAL SYSTEM FOR
LATER WEDNESDAY THROUGH NEXT FRIDAY. THUS, ANOTHER ROUND OF
PRECIPITATION SHOULD BE EXPECTED FOR LATE NEXT WEEK,GREATEST OVER
NORTHWEST SECTIONS AND LEAST OVER SOUTHEAST SECTIONS. BTL
&&
.AVIATION...
THIS EVENING...OVER COASTAL LOCATIONS...EXPECT MVFR CIGS TO
BECOME WIDESPREAD AS MARINE STRATUS MOVES INTO THE COAST. VFR WILL
CONTINUE INLAND THIS EVENING...THEN THE MARINE LAYER IS EXPECTED
TO PUSH INLAND TONIGHT WITH MVFR CEILINGS LIKELY TONIGHT AND
SUNDAY MORNING FROM THE COAST TO THE UMPQUA BASIN AND ROGUE
VALLEY. ALONG THE COAST AND INLAND...MVFR CIGS ARE EXPECTED TO
CLEAR TO VFR AROUND 15-17Z SUNDAY MORNING WITH LINGERING AREAS OF
MVFR IN THE UMPQUA THROUGH THE LATE MORNING. EAST SIDE LOCATIONS
SHOULD REMAIN VFR TONIGHT AND SUNDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 219 PM PDT SAT APR 28 2012/
DISCUSSION...UPPER LEVEL RIDGE NUDGES INTO THE REGION FROM
OFFSHORE THIS EVENING WITH SUBSIDENCE DRYING OUT THE ATMOSPHERE
ABOVE 700 MB. LIGHT AND LOW TOPPED SHOWERS WILL DIMINISH QUICKLY
AFTER SURFACE HEATING IS LOST WITH MOIST ONSHORE FLOW CONTINUING
TO BRING LIGHT PRECIP MOSTLY IN THE FORM OF DRIZZLE TO THE COAST
NORTH OF CAPE BLANCO. A BREAK IN THE ACTION COMES SUNDAY AHEAD OF
THE NEXT SYSTEM THAT MOVES IN MONDAY MORNING AFTER THE UPPER RIDGE
PATTERN FLATTENS AND TRANSFORMS INTO A NORTHWEST ZONAL FLOW
PATTERN. THE NOSE OF THE +120KT JET IS POINTED DIRECTLY AT
PORTLAND MONDAY MORNING WITH THE BEST JET DYNAMICS NORTH OF OUR
REGION...BRINGING THE HIGHEST PRECIPITATION AMOUNTS NORTH OF THE
REGION. THIS JET SPLITS WITH THE NORTH BRANCH WEAKENING AND THE
SOUTHERLY SPLIT STRENGTHENING WITH THE NOSE POINTING INTO NORTHERN
CALIFORNIA BY TUESDAY MORNING. HOWEVER...FLOW BECOMES A MORE
STABLE WESTERLY FLOW UP THROUGH 700 MB DURING THE BEST DYNAMICS.
COOLER AIR MOVING IN ALOFT KEEPS SHOWERS WEST OF THE CASCADES AND
IN THE CASCADES. 700 MB WINDS FROM THE WEST AT AROUND 35 KT IN
THE LEFT EXIT REGION IN THE COOLER AIR POOL ALOFT MONDAY NIGHT
CONTINUES SHOWERS THROUGH MOST OF THE NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY...MODELS ARE IN GOOD
AGREEMENT SHOWING A LOW PRESSURE SYSTEM APPROACHING THE COAST
WEDNESDAY EVENING WITH A FRONT PUSHING INLAND WEDNESDAY NIGHT AND
THURSDAY. THERE ARE SLIGHT DIFFERENCES IN THE HANDLING OF THIS LOW.
OVERALL MODELS AGREE THIS SYSTEM WILL LIKELY BRING RAIN INTO AREAS
FROM THE CASCADES WEST WEDNESDAY AFTERNOON AND EVENING AS THE WARM
FRONT PUSHES INLAND...THEN ADDITIONAL RAIN WEDNESDAY NIGHT AND
THURSDAY AS THE COLD FRONT PUSHES INLAND. THE ECMWF HAS A SLIGHTLY
MORE SOUTHERLY TRACK WITH THE LOW AND IS A WETTER DURING THIS
PERIOD. ALSO EXPECT GUSTY SOUTHWESTERLY WINDS ON THURSDAY AHEAD OF
THE COLD FRONT...ESPECIALLY OVER HIGHER TERRAIN AND FOR LOCATIONS
EAST OF THE CASCADES. THURSDAY NIGHT SHOWERS PERSIST ESPECIALLY OVER
WESTERN PORTIONS OF THE AREA...THEN TAPER OFF ON FRIDAY AS THE
SYSTEM LIFTS NORTHEAST. BY SATURDAY...THE MODEL DIFFERENCES
INCREASE. THE GFS SHOWS A WESTERLY FLOW BUT DRY PATTERN WHILE THE
ECMWF BRINGS A DEEPENING UPPER LOW INTO NORTHERLY CALIFORNIA WITH
SHOWERS POSSIBLE. HAVE KEPT IN A SLIGHT CHANCE FOR PRECIPITATION ON
SATURDAY GIVEN THE UNCERTAINTY.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 8 PM PDT SUNDAY FOR
PZZ356.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM PDT SUNDAY
FOR PZZ356-376.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 8 PM PDT SUNDAY FOR
PZZ376.
$$
BTL/SVEN/CC
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1151 PM CDT SAT APR 28 2012
.AVIATION...
FOR THE 06Z TAFS...TIMING THE ONSET OF MVFR STRATUS CONTINUES TO
BE THE PRIMARY FORECAST CONCERN.
THE ONLY CHANGE FROM THE PREVIOUS TAF ISSUANCE WAS TO BACK UP THE
TIMING OF THE ONSET OF STRATUS BY ONE HOUR FOR ALL AREA TAF SITES.
STRATUS REMAINS LARGELY UNORGANIZED UPSTREAM...HOWEVER A MORE
SOLID DECK OF STRATUS APPEARS TO BE ORGANIZING JUST SOUTH OF
AUSTIN AS OF 05Z. EXPECT THAT STRATUS WILL MOVE NORTH ON THE LOW
LEVEL JET ONCE AGAIN TONIGHT...SO DID NOT REMOVE MVFR CIGS OR
CHANGE THE EXPECTED HEIGHTS OF THE CEILINGS ANY. THE REMAINDER OF
THE FORECAST REMAINS UNCHANGED.
CAVANAUGH
.../PREVIOUS AVIATION DISCUSSION/...
FOR THE 00Z TAFS...TIMING THE ONSET OF MVFR STRATUS IS THE PRIMARY
FORECAST CONCERN THROUGH THE VALID FORECAST PERIOD.
DID NOT MAKE MUCH IN THE WAY OF CHANGES TO PREVIOUS FORECAST.
BACKED UP THE ONSET OF STRATUS OVER METROPLEX AREA TAF SITES BY AN
HOUR BASED ON RUC FORECAST SOUNDINGS. OTHERWISE AGREE THAT STRATUS
WILL LIKELY HOLD ABOVE 2 KFT FOR METROPLEX AREA TAF SITES AND
SHOULD CLIMB 3 KFT BEFORE SCATTERING OUT TOMORROW MORNING. WACO
WILL GET INTO THE STRATUS A BIT EARLIER AND CIGS SHOULD HOLD A FEW
HUNDRED FEET LOWER THAN METROPLEX AREA TAF SITES. CONDITIONS WILL
ALSO LIKELY RETURN TO VFR AN HOUR OR SO LATER THAN METROPLEX AREA
SITES.
ONCE AGAIN THINK THAT THUNDERSTORM ACTIVITY WILL REMAIN WELL OFF
TO THE NORTHWEST OF THE METROPLEX OVER THE NEXT 24 TO 36 HRS AND
HAVE NOT INCLUDED ANY MENTION OF TSTM ACTIVITY IN THE TAFS. THE
SURFACE BOUNDARY NEAR WICHITA FALLS IS ACTUALLY EXPECTED TO
RETREAT TO THE NORTHWEST OVERNIGHT AND AS THIS IS EXPECTED TO PLAY
A KEY ROLE IN TSTM INITIATION...DO NOT THINK THAT ANY TSTM
ACTIVITY WILL BE ABLE TO AFFECT AREA TAF SITES.
CAVANAUGH
&&
.UPDATE...
A FEW THUNDERSTORMS HAVE DEVELOPED NEAR A RETREATING SURFACE
BOUNDARY STRETCHING FROM WEST OF THE CWA INTO OKLAHOMA. THE
STRONGEST STORM IS CURRENTLY LOCATED NEAR ASPERMONT AND IS MOVING
TO THE EAST AROUND 20-25 MPH. CURRENT EXTRAPOLATION WOULD BRING
THIS CELL INTO STEPHENS/YOUNG COUNTY AROUND MIDNIGHT...BUT DO NOT
ANTICIPATE IT HOLDING ITS STRENGTH FOR THE NEXT 3 HOURS AS CIN IS
EXPECTED TO INCREASE. ALSO...DO NOT EXPECT ITS MOVEMENT TO REMAIN
EAST. AS THE STORM WEAKENS...ITS FORWARD MOVEMENT WILL BECOME MORE
NORTHEASTERLY. CURRENT POP CONFIGURATION STILL LOOKS FINE...WITH
20 POPS NORTH OF AN EASTLAND TO DECATUR TO SHERMAN LINE. WILL ONLY
MAKE MINOR ADJUSTMENTS TO THE HOURLY GRIDS.
85/NH
&&
.PREV DISCUSSION... /ISSUED 252 PM CDT SAT APR 28 2012/
A SHORTWAVE ROTATING AROUND THE UPPER LEVEL LOW IN THE NORTHERN
PLAINS IS NOW MOVING INTO THE TEXAS AND OKLAHOMA PANHANDLES.
MEANWHILE A FRONT HAS STALLED JUST NW OF THE CWA BORDER...ALONG A
LINE FROM ABI-SPS-OKC. CIN REMAINS HIGH DUE TO A STRONG INVERSION
NEAR 800MB...BUT WILL BEGIN TO LIFT/ERODE ACROSS THE NW ZONES LATE
THIS AFTERNOON AND EVENING AS FORCING FROM THE SHORTWAVE ARRIVES.
ALTHOUGH CONVERGENCE ALONG THE FRONTAL BOUNDARY IS FAIRLY WEAK ON
THE TEXAS SIDE...EXPECT A FEW STORMS TO DEVELOP BY EARLY EVENING.
STORM MOTION WILL BE GENERALLY TO THE NORTHEAST AND THUS WILL KEEP
THE LOW POPS RESTRICTED TO JUST THE NW ZONES TONIGHT. DEEP LAYER
SHEAR OF 35KT AND SBCAPE OF UP TO 2000 J/KG SUGGESTS STORM MODE
WILL WAFFLE BETWEEN MULTICELL AND BRIEF SUPERCELL. A LOW SEVERE
THREAT IS POSSIBLE IN THE FAR NW ZONES THIS EVENING...WITH HAIL
AND DAMAGING WINDS THE PRIMARY HAZARD. OTHERWISE...SOUTH WINDS
OF 10-20 MPH WILL ENSURE ANOTHER MILD NIGHT ACROSS NORTH TEXAS
WITH LOW STRATUS ARRIVING AFTER MIDNIGHT. MID-HIGH MOISTURE/CLOUDS
WILL ALSO BE ON THE INCREASE FROM THE SOUTHWEST AND WE MAY SEE
SOME RADAR ECHOES FROM VIRGA MOVE ACROSS THE REGION TONIGHT.
MORE ABUNDANT CLOUD COVER TOMORROW WILL HELP KEEP HIGH TEMPS A
COUPLE OF DEGREES COOLER THAN TODAY. ANOTHER SHORTWAVE WILL MOVE
THROUGH THE SOUTHERN PLAINS SUNDAY NIGHT. MOST OF THE CONVECTION
SUNDAY AFTERNOON AND EVENING WILL BE ACROSS OKLAHOMA...BUT SOME
OF THIS ACTIVITY MAY WANDER INTO THE NW ZONES WITH THE AID OF
CONVECTIVE OUTFLOWS. THE CAP WILL REMAIN TOO STRONG OVER THE
REMAINDER OF NORTH TEXAS THROUGH SUNDAY NIGHT FOR A MENTION OF
POPS. HOWEVER...FORCING FROM THE SHORTWAVE MAY LIFT THE CAP JUST
ENOUGH NORTH OF I-20 BY MONDAY MORNING FOR THE NORTHERN HALF OF
THE CWA TO HAVE A LOW CHANCE OF RAIN MONDAY WITH DAY-TIME HEATING.
THE REMAINDER OF THE FORECAST IS RATHER BENIGN AS THE UPPER LEVEL
PATTERN BECOMES STATIC WITH WEAK TROUGHING ACROSS THE NORTHERN
ROCKIES. THIS WILL KEEP A MOIST SOUTHERLY FLOW AT 15 TO 20 MPH IN
PLACE. EXPECT MILD OVERNIGHT LOWS IN THE MID-UPPER 60S WITH LATE
NIGHT AND MORNING LOW CLOUDS. AFTERNOONS WILL FEATURE SUNSHINE AND
HIGHS IN THE MID-UPPER 80S...BUT CAP LOOKS STRONG ENOUGH TO
PRECLUDE MENTIONING ANY RAIN CHANCES. MODELS ARE STILL STRUGGLING
TO RESOLVE UPPER LEVEL FEATURES BY THE END OF THE FORECAST PERIOD.
THE GFS IS NOW AN OUTLIER AS IT SHOWS STRONGER UPPER RIDGING AND A
WEAK FRONT BY SATURDAY. WILL SIDE WITH THE OTHER MODELS AND KEEP
THE WARM/DRY PERSISTENCE TREND IN PLACE.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 67 84 69 86 69 / 10 10 10 20 10
WACO, TX 69 84 69 86 69 / 5 10 10 10 10
PARIS, TX 65 82 66 82 66 / 10 10 10 20 10
DENTON, TX 65 83 67 85 68 / 10 10 20 20 10
MCKINNEY, TX 65 83 67 84 67 / 10 10 10 20 10
DALLAS, TX 68 84 69 85 69 / 10 10 10 20 10
TERRELL, TX 66 83 69 84 68 / 5 10 10 20 10
CORSICANA, TX 67 84 69 85 68 / 5 10 10 10 10
TEMPLE, TX 69 85 69 86 68 / 5 10 10 10 10
MINERAL WELLS, TX 66 83 66 86 67 / 10 20 20 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1223 AM CDT SUN APR 29 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY
315 PM CDT SAT APR 28 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SUNDAY AFTERNOON
INTO MONDAY...THEN TEMPERATURES AND PRECIPITATION CHANCES TUESDAY.
LATEST MOSAIC RADAR INDICATING FRONTOGENETICAL BAND EXTENDING FROM
LAKE MICHIGAN TO WESTERN MINNESOTA WEAKENING AND SHRINKING...THIS
IS IN AGREEMENT WITH THE 28.18Z RUC 700-600MB FN VECTOR CONVERGENCE
WEAKENING THE FRONTOGENETICAL BAND THIS AFTERNOON INTO THIS
EVENING.
THE 28.12Z GFS/NAM ARE IN PRETTY GOOD AGREEMENT IN LIFTING UPPER
LEVEL LOW OVER THE NORTHERN PLAINS NORTHWARD INTO CANADA SUNDAY
NIGHT AND DEVELOPING SOUTHWESTERLY FLOW ALOFT MONDAY NIGHT INTO
TUESDAY. DPROG/DT OF THE 28.12Z GFS AND NAM SHOW SHORTWAVE TROUGH
WRAPPING AROUND THE UPPER LEVEL LOW INTO THE AREA FASTER THE LAST
SEVERAL RUNS. CONFIDENCE IS INCREASING PRECIPITATION WILL
OVERSPREAD THE REGION SUNDAY AFTERNOON. NO SIGNIFICANT DIFFERENCES
NOTED BETWEEN THE 28.12Z DETERMINISTIC MODELS.
TONIGHT INTO MONDAY...FRONTOGENETICAL BAND OVER OVER WESTERN
AND CENTRAL WISCONSIN WILL CONTINUE TO WEAKEN THIS EVENING. THEN...
WEAK RIDGE BUILDS INTO EASTERN WISCONSIN AFTER MIDNIGHT TONIGHT
INTO SUNDAY MORNING. DRY WEATHER CONDITIONS ARE EXPECTED AFTER 06Z
TO AROUND 18Z SUNDAY. THE 28.12Z GFS/NAM/ECMWF ARE MORE PROGRESSIVE
WITH SHORTWAVE ROTATING AROUND UPPER LEVEL LOW INTO THE FORECAST
AREA. THE 28.12Z GFS/NAM SHOW DECENT ISENTROPIC LIFT AT 305K
SURFACE...MOISTURE TRANSPORT AND CONVERGENCE AT 925-850MB LAYER...
IN ASSOCIATION WITH THE SHORTWAVE TROUGH. HAVE INCREASED
PRECIPITATION CHANCES FROM 18Z SUNDAY TO 12Z MONDAY. THE 28.12Z
GFS/NAM SHOW AROUND 100 J/KG 0-6KM MOST UNSTABLE CAPE ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN...INTRODUCED ISOLATED THUNDER
ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN AFTER 18Z SUNDAY. WITH
THE MODELS INDICATING A FASTER SOLUTION WITH THE SHORTWAVE TROUGH...
EXPECT MUCH OF THE PRECIPITATION TO BE EAST OF THE FORECAST AREA BY
18Z MONDAY.
NEXT FORECAST CONCERN IS THE 28.12Z GFS/NAM DEVELOPING SOUTHWESTERLY
FLOW ALOFT OVER ROCKY MOUNTAINS AND UPPER MIDWEST MONDAY NIGHT INTO
TUESDAY. THE DETERMINISTIC MODELS ARE ADVECTING WARMER AIR INTO THE
FORECAST AREA WITH 850MB TEMPERATURES RISING TO PLUS 12 TO PLUS 15
DEGREES CELSIUS BY 00Z WEDNESDAY. HIGH TEMPERATURES TUESDAY WILL BE
MAINLY IN THE LOWER TO MIDDLE 70S...WITH THE POSSIBILITY OF 80
DEGREES OVER NORTHEAST IOWA OR SOUTHEAST MINNESOTA. THE 28.12Z
GFS/NAM DO SHOW MOISTURE TRANSPORT AND ISENTROPIC LIFT AT 305K
SURFACE...MAINLY AFTER 18Z TUESDAY ACROSS THE FORECAST AREA. THE
28.12Z GFS/NAM INDICATE DECENT 0-3KM SHEAR AND INSTABILITY DURING
THE DAY TUESDAY. HOWEVER...THE BEST LIFT AND CONVERGENCE AT THIS TIME
APPEARS TO BE NORTHWEST AND SOUTHWEST OF FORECAST AREA AND HAVE KEPT
SMALL CHANCES OF PRECIPITATION ACROSS FORECAST AREA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
315 PM CDT SAT APR 28 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES THROUGH THE
PERIOD AND UNSEASONABLY WARM TEMPERATURES THROUGH THURSDAY. THE
28.12Z GFS/GEM/ECMWF CONTINUE TO DEVELOP WEST TO SOUTHWESTERLY FLOW
ALOFT AND CONTINUE TO HAVE DIFFERENCES IN TIMING OF SHORTWAVE
TROUGHS EMBEDDED IN THE WEST TO SOUTHWESTERLY FLOW ALOFT THROUGH
THE PERIOD. CONFIDENCE IN TIMING OF THE INDIVIDUAL SHORTWAVE TROUGHS
MOVING INTO THE UPPER GREAT LAKES REGION IS LOW...HOWEVER
CONFIDENCE IS INCREASING AN ACTIVE WEATHER PATTERN WILL SET UP OVER
THE UPPER GREAT LAKES AND UPPER MIDWEST REGION MIDDLE OF NEXT WEEK.
THE DETERMINISTIC 28.12Z GFS/GEM/ECMWF SHOW WARM AIR ADVECTING INTO
THE FORECAST AREA TUESDAY NIGHT AND CONTINUING INTO THURSDAY...WITH
850MB TEMPERATURES RANGING FROM PLUS TWELVE DEGREES CELSIUS TO
PLUS FIFTEEN DEGREES CELSIUS AND THE 28.00Z GEFS INDICATING
STANDARD ANOMALIES OF 1-1.5. EXPECT TEMPERATURES TO BE
WELL ABOVE NORMAL THROUGH THE MIDDLE OF NEXT WEEK ACROSS FORECAST
AREA.
&&
.AVIATION...THROUGH 06Z MONDAY
1223 AM CDT SUN APR 29 2012
LOW STRATUS WILL PRODUCE IFR CONDITIONS AT KRST THROUGH 10Z THIS
MORNING WITH CLOUD BASES IN THE 700 TO 900 FT RANGE. IN
ADDITION...AREAS OF BR WILL REDUCE VISIBILITIES TO AROUND 4 SM AT
TIMES. PLAN ON VFR CONDITIONS AT KSLE TODAY WITH CLOUD BASES
AROUND 4 KFT EARLY THIS MORNING...IMPROVING TO AROUND 10 KFT BY
THE LATE MORNING HOURS. PLAN ON IMPROVING CEILINGS AT KRST AFTER
10Z WITH VFR CONDITIONS EXPECTED BY 15Z. THE NEXT SYSTEM LOOKS TO
PUSH INTO THE REGION LATE THIS AFTERNOON INTO THIS EVENING FROM
THE CENTRAL PLAINS...BRINGING A CHANCE OF SHOWERS TO THE TAF
SITES. IN ADDITION...CEILINGS WILL LOWER THIS EVENING WITH
MVFR/IFR CEILINGS EXPECTED BY LATE TONIGHT. WINDS WILL BE OUT OF
THE EAST/SOUTHEAST TODAY AT 7 TO 13 KTS...POSSIBLY GUSTING TO
AROUND 21 KTS THIS AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 PM CDT SAT APR 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
955 AM EDT SUN APR 29 2012
.UPDATE (TODAY-TONIGHT)...
14Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING NORTHERN STREAM FLOW
CARVING OUT A LONGWAVE TROUGH INTO THE FOUR-CORNERS REGION AROUND A
LARGE CUTOFF LOW SPINNING OVER THE HIGH PLAINS. SHORTWAVE ENERGY
WITHIN THIS FLOW IS NOW EJECTING EASTWARD FROM THE INTER-MOUNTAIN
WEST TOWARD THE CENTRAL PLAINS AND IS HELPING TO FORCE A LARGE AREA
OF SHOWERS AND STORMS FROM OK/KS EASTWARD TO THE MIDDLE MS VALLEY.
NORTHERN STREAM FLOW THEN RIDGES NORTHWARD INTO THE GREAT LAKES
BEFORE CARVING OUT ANOTHER TROUGH OVER THE NORTHEASTERN STATES.
CLOSER TO HOME...OUR FORECAST AREA IS WEDGED BETWEEN UPPER LEVEL
RIDGING OVER THE NORTHERN GULF COAST/SE STATES...AND AN UPPER LEVEL
DISTURBANCE FROM THE NW CARRIBEAN SEA TO THE BAHAMAS. THIS ENERGY IS
FORCING A LARGE AREA OF RAINFALL/EMBEDDED THUNDER OVER THE FAR
SOUTHERN FL PENINSULA...FL STRAITS AND BAHAMAS THIS MORNING. THE
DEEP COLUMN MOISTURE CONTINUES TO TRY AND MOVE NORTHWARD...BUT FOR
NOW IS STILL CONFINED TO AREAS SOUTH OF TAMPA BAY. ALTHOUGH THE 12Z
KTBW SOUNDING SHOWS SOME MOISTENING OVER THE PAST 24 HOURS WITH A PW
VALUE UP TO 1.25"...MIAMI`S KMFL PROFILE IS MUCH MORE MOIST WITH AN
ESSENTIALLY SATURATED COLUMN BELOW 500MB AND A PW VALUE OVER 2".
AT THE SURFACE...
FORECAST AREA REMAINS IN BETWEEN A RIDGE OF HIGH PRESSURE EXTENDING
FROM OFF THE SE COAST WESTWARD ALONG OR JUST NORTH OF THE I-10
CORRIDOR...AND A DEVELOPING LOW/INVERTED TROUGH OVER THE FL STRAITS.
LOW LEVEL FLOW BETWEEN THESE TWO FEATURES IS PROVIDING A LIGHT TO
MODERATE EASTERLY BREEZE ACROSS THE REGION.
REST OF TODAY/TONIGHT...UPPER LEVEL SYNOPTIC SUPPORT AND LOW LEVEL
FOCUS FOR ASCENT WILL BE MAINTAINED OVER THE SOUTHERN THIRD OF THE
PENINSULA KEEPING A STEADY SUPPLY OF MOISTURE/RAINFALL MOVING ASHORE
(GENERALLY SOUTH OF A LINE FROM FORT MYERS TO WEST PALM BEACH).
WOULD EXPECT TO SEE SOME SCT CONVECTION DEVELOP INTO OUR SOUTHERN
ZONES THIS AFTERNOON DUE TO DIFFERENTIAL HEATING AND THE SYNOPTIC
SUPPORT ALOFT. FURTHER NORTH TOWARD THE TAMPA BAY REGION AND NATURE
COAST...THE INFLUENCE/SUPPRESSION FROM THE UPPER RIDGE SHOULD BE
MORE DOMINANT AND KEEP ANY AFTERNOON/EVENING SHOWER ACTIVITY VERY
ISOLATED (IF ANY). RAIN CHANCES WILL RANGE FROM THE LIKELY RANGE FAR
SOUTH...TO SLIGHT/CHANCE/CHANCE FOR SARASOTA/MANATEE/HARDEE/DE
SOTO...AND HIGHLANDS COUNTIES...AND FINALLY SILENT 10% OR LESS RAIN
CHANCES FROM PINELLAS/HILLSBOROUGH/POLK COUNTIES NORTHWARD.
WARMEST TEMPERATURES WILL ALSO BE OVER THE NORTHERN ZONES WHERE MORE
INSULATION/DEEP LAYER SUPPRESSION WILL SOAR AFTERNOON HIGHS INTO THE
UPPER 80S TO NEAR 90 AWAY FROM THE COAST. THE THICKER CLOUDS AND
EVENTUALLY SHOWER CHANCES SHOULD HOLD TEMPS IN THE UPPER 70S/LOW 80S
DOWN TOWARD CHARLOTTE AND LEE COUNTIES.
MORE OF THE SAME OVERNIGHT WITH ANY SHOWER ACTIVITY CONFINED TO
MAINLY LEE AND CHARLOTTE COUNTIES...AND DRY CONDITIONS FURTHER
NORTH. TEMPS WILL BE WARM (MID 60S TO LOW 70S) DUE TO ABUNDANT LOW
LEVEL MOISTURE STREAMING WESTWARD ACROSS THE PENINSULA FROM THE
ATLANTIC.
&&
.AVIATION...
VFR CIGS FROM TPA-PGD AROUND 250...AREA OF RAIN JUST SOUTH OF
FMY/RSW WILL GRADUALLY EDGE NORTH WITH SHOWERS DEVELOPING BY
AFTERNOON OVER FMY/RSW WITH GENERALLY VFR CIGS/VSBYS BUT LCL MVFR
CIGS/VSBYS. SLIGHT CHANCE OF AFTERNOON SHOWERS FROM TPA TO PGD
LATER THIS AFTERNOON...BUT BULK OF THE RAIN WILL REMAIN JUST SOUTH
OF TERMINALS OVER SOUTHWEST FLORIDA.
&&
.MARINE...
LOW PRESSURE DEVELOPING IN THE FLORIDA STRAITS AND PUSHING SLOWLY
WEST OVER THE NEXT SEVERAL DAYS WILL BRING A TIGHTENING PRESSURE
GRADIENT AND INCREASING EASTERLY FLOW. WILL ADD SMALL CRAFT
ADVISORY TO SOUTHERN WATERS BEGINNING TONIGHT AS WINDS AROUND 20
KNOTS ARE EXPECTED AND SEAS INCREASING TO 6 FT. WILL REMAIN WITH
ELEVATED WINDS AND SEAS THROUGH EARLY TUESDAY AS THE LOW PRESSURE
MOVES INTO THE SOUTHERN GULF AND DISSIPATES. EASTERLY FLOW TO
CONTINUE THROUGH THE MAJORITY OF THE COMING WORK WEEK WITH A
STRONG RIDGE OF SURFACE HIGH PRESSURE SLIDING OFF THE EAST COAST
AND INTO THE SOUTHWEST ATLANTIC.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 71 87 71 / 10 10 10 5
FMY 83 69 83 69 / 60 30 40 30
GIF 89 68 86 68 / 10 10 10 5
SRQ 87 70 86 68 / 20 10 20 10
BKV 90 65 90 65 / 5 0 10 0
SPG 89 74 84 74 / 15 10 10 5
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8
AM EDT TUESDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM.
&&
$$
UPDATE...14/MROCZKA
AVIATION...13/OGLESBY
AREA FORECAST DISCUSSION
NWS GOODLAND KS
757 AM MDT SUN APR 29 2012
.UPDATE...
ISSUED AT 742 AM MDT SUN APR 29 2012
MADE A FEW QUICK UPDATES TO THE FORECAST...MAINLY TO ACCOUNT FOR A
FARTHER WESTWARD EXTENT OF FOG AS SOME MINOR VISIBILITY
RESTRICTIONS OBSERVED AS FAR WEST AS OBERLIN AND MCCOOK.
WATER VAPOR IMAGERY/RUC PV ANALYSIS INDICATING TWO SEPARATE SHORT
WAVE TROUGHS APPROACHING THE AREA...ONE ALONG THE WESTERN COLORADO
BORDER AND THE SECOND ALONG THE SOUTHEAST CO BORDER. WHILE THERE
HAS BEEN A LULL IN PRECIPITATION ACROSS THE AREA...INCREASE IN WEAK
ECHOES ACROSS THE NORTHERN CWA SUPPORTS INCREASED ASCENT WITH THIS
APPROACHING FIRST TROUGH...AND HAVE FINE TUNED POPS OVER THE NEXT
2-3 HOURS TO FOCUS MORE IN THE NORTHERN CWA AS PER LAST FEW RUNS
OF RUC WHICH SEEMS TO BE SUPPORTED BY LATEST TRENDS...ALTHOUGH
CANNOT RULE OUT AN ISOLATED SHOWER FARTHER SOUTH/EAST WITH INITIAL
TROUGH.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 300 AM MDT SUN APR 29 2012
SHOWERS AND PERHAPS A THUNDERSTORM POSSIBLE THIS MORNING AS A
WEATHER DISTURBANCE LIFTS NORTH OF THE INTERSTATE. A MORE VIGOROUS
DISTURBANCE MOVES IN FROM THE SOUTHWEST LATE IN THE DAY BRINGING
AN INCREASE IN THUNDERSTORMS THROUGH MID EVENING...SOME OF WHICH
MAY BECOME SEVERE. THIS DISTURBANCE WILL EXIT TO THE EAST OF THE
AREA LATE TONIGHT THROUGH MONDAY WITH A DOWNWARD TREND IN
PRECIPITATION CHANCES.
HIGH TEMPERATURES TODAY IN THE 60S WITH LOW TO MID 70S MONDAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN APR 29 2012
MONDAY NIGHT-TUESDAY...MAY SEE A THUNDERSTORM OR TWO ACROSS THE FAR
EASTERN 1/4 OF THE AREA OTHERWISE MUCH WARMER WITH AFTERNOON HIGHS
IN THE LOW 80S IN FAR EASTERN COLORADO...MID 80S EAST OF THE CO/KS
BORDER.
WEDNESDAY THROUGH SATURDAY...NOT TOO MUCH CHANGE IN WHAT THE MODELS
WERE SHOWING FROM 24 HOURS AGO. BEGINNING OF THE PERIOD STARTS OUT
IN A FAST NEARLY ZONAL FLOW. ON FRIDAY AN UPPER LEVEL RIDGE BUILDS
INTO THE AREA FOLLOWED BY A STRONGER SOUTHWESTERLY FLOW THAN WHAT
OCCURRED EARLIER IN THE PERIOD. MODELS AND ENSEMBLES ARE A LITTLE
BETTER THAN WHAT THEY SHOWED YESTERDAY BUT THERE ARE STILL SOME
DIFFERENCES ALOFT...ESPECIALLY TOWARD THE END OF THE PERIOD.
AS SAID YESTERDAY...HARD TO GET TOO DEFINITE ABOUT PRECIPITATION
CHANCES WITH THE SMALL SCALE WAVES EMBEDDED WITHIN THIS FLOW.
HOWEVER AS IT LOOKS NOW WITH THE BUILDING RIDGE INTO THE AREA
...FRIDAY DEFINITELY LOOKS THE DRIEST. OTHERWISE...LOW CHANCES OF
PRECIPITATION WILL EXIST NEARLY EVERY DAY WITH BETTER CHANCES
POSSIBLE AT THE END OR JUST BEYOND THIS PERIOD. TEMPERATURES WILL BE
ABOVE NORMAL WITH FRIDAY AND SATURDAY HAVING THE POTENTIAL TO BE
WARMER THAN WHAT IS IN THERE DUE TO THE STRONG RIDGING AND DEEP
SOUTHWESTERLY FLOW ALOFT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 300 AM MDT SUN APR 29 2012
FOR KGLD...VFR EXPECTED. MAY HAVE A FEW SHOWERS NEAR THE TERMINAL
AROUND 15Z-20Z WITH THUNDERSTORMS EXPECTED AROUND 00Z CONTINUING
THROUGH 04Z OR SO. SHOULD A THUNDERSTORM DIRECTLY IMPACT THE
TERMINAL VIS AND/OR CIG MAY DROP INTO MVFR RANGE. AFTER 06Z CIGS
AND VIS EXPECTED TO LOWER INTO MVFR/IFR RANGE AS LOW LEVELS
SATURATE AND FOG DEVELOPS.
FOR KMCK LIGHT PRECIPITATION POSSIBLE AFTER 21Z WITH THUNDERSTORMS
POSSIBLE EARLY EVENING INTO THE OVERNIGHT HOURS. FOG WILL ALSO
DEVELOP AFTER 06Z OR SO WHERE MVFR/IFR CIGS/VIS POSSIBLE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JRM
SHORT TERM...007
LONG TERM...007/BULLER
AVIATION...007
AREA FORECAST DISCUSSION
NWS PADUCAH KY
956 AM CDT SUN APR 29 2012
.UPDATE...
ISSUED AT 951 AM CDT SUN APR 29 2012
UPDATED THE PUBLIC FORECAST TO PUSH IT TOWARD THE HRRR FORECAST.
LOOKS LIKE WE MAY HAVE A REPEAT OF YESTERDAY...WITH MOST OF THE
THUNDERSTORM ACTIVITY STAYING JUST NORTH OF THE FORECAST AREA. THE
HRRR LIFTS THE BOUNDARY NORTHWARD TO NEAR INTERSTATE 64 BY THE END
OF THE DAY...AND DESPITE SOME HIGH CLOUDS THERE SHOULD BE PLENTY
OF SUNSHINE SOUTH OF THE BOUNDARY TO ALLOW TEMPERATURES TO CLIMB
WELL INTO THE 80S. KEPT THE AFTERNOON POPS...BUT DRIED OUT THIS
MORNING. WILL GET A LOOK AT ALL OF THE 12Z GUIDANCE BEFORE WIPING
OUT MORE OF THE AFTERNOON POPS. ALSO INCREASED SOUTHERLY WINDS
OVER THE SOUTHERN HALF OF THE AREA THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 315 AM CDT SUN APR 29 2012
WITH CONVECTION STILL FIRING NEAR THE DOORSTEP OF THE NORTHERN WFO
PAH FORECAST AREA AT PRESS TIME...THERE IS SOME CONCERN ON THE
EVENTUAL SOUTHWARD EXTENSION OF THE CONVECTION LATER TODAY. THE
LAST SEVERAL RUNS OF THE LAPS MASS/MOISTURE/INSTABILITY FIELDS
SHOW SOME RETRACTION OF THE THE MAIN THETA-E RIDGE BACK INTO
SOUTHERN MISSOURI. THIS IS IN LINE WITH THE DEEPER THETA-E RIDGE
DEPICTED ON THE 00Z SUNDAY MANDATORY UPPER AIR CHARTS. THERE IS
ALSO A DEPICTION OF A SECONDARY...BUT LESS EFFECTIVELY ORIENTED
WEST TO EAST THETA-E MAX ALONG THE OHIO RIVER BORDERING
KENTUCKY...INDIANA AND OHIO. ALTHOUGH FORCING WITH MINOR UPPER
LEVEL JET SUPPORT IN THE AFOREMENTIONED AREA MAY BE A CONCERN
EARLY ON...RIDGING ALOFT MAY MITIGATE ANY ORGANIZED
CONVECTION...LEAVING DIURNALLY GENERATED OUTFLOW CONVECTION THE
PRIMARY THUNDERSTORM FOCUS OVER SOUTHWEST INDIANA. SOUTHWEST
INDIANA AND NORTHWEST KENTUCKY WILL BE A TOSS UP ON THUNDERSTORM
COVERAGE...PERSISTENCE AND INTENSITY THIS AFTERNOON AND INTO EARLY
THIS EVENING. LATER SHIFTS WILL NEED TO MONITOR THIS AREA AND MAKE
ADJUSTMENTS ACCORDINGLY. THE SOUTHERN EXTENT OF THE CONVECTION
TODAY...AT ITS MAXIMUM...LINES UP WITH THE EARLY MORNING DAY ONE
SPC SEVERE WEATHER OUTLOOK. AGAIN...WITH THE BOUNDARY
NEARBY...THERE IS GOING TO BE A SHARP DEMARCATION ON RAIN VERSUS
NO RAIN TODAY.
ALTHOUGH THE NAM-WRF HAS BEEN AN EXCELLENT PERFORMER THE LAST FEW
MODEL RUNS...THE DETERMINISTIC GFS AND ECMWF APPEARED TO HAVE A
GOOD HANDLE ON THE OVERALL SYNOPTIC PICTURE WITH RESPECT TO THE
LOW LEVEL RIDGING OVER THE WFO PAH AREA...AS THICKNESSES AND
HEIGHTS RAISE IN ADVANCE OF THE THE LARGE NORTHWEST U.S. CLOSED
LOW. ADJUSTED MAX/MIN TEMPERATURES 1-2 DEGREES HIGHER OUTSIDE OF
THE EXPECTED CONVECTIVE ACTIVITY TODAY THROUGH TUESDAY. THE ONLY
CAVEAT WILL BE THE IMPACT OF PERSISTENT OR TRANSIENT CLOUD COVER
ON THESE TEMPERATURES THE NEXT SEVERAL DAYS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 315 AM CDT SUN APR 29 2012
HPC PREFERS A GEFS/GFS BLEND SOLUTION IN THE LONG TERM...WITH MORE
WEIGHT GIVEN TO THE GEFS DAY 5 AND BEYOND. WE AGREE GIVEN THE ECMWF
SEEMS TO BE FLIP FLOPPING QUITE A BIT IN SOME RESPECTS. ALL IN ALL
STILL A LOW CONFIDENCE PRECIPITATION FORECAST GIVEN THE NATURE OF
THE UPPER FLOW PATTERN. CONFIDENCE IS RELATIVELY HIGH THOUGH...THAT
TEMPERATURES WILL RUN ABOVE NORMAL.
NOT MUCH TO TRIGGER CONVECTION TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
SOUTHWEST FLOW ALOFT MAY CONTAIN A WEAK IMPULSE OR TWO...THAT
COMBINED WITH A LITTLE INSTABILITY COULD TRIGGER VERY ISOLD
CONVECTION. HOWEVER DOES NOT APPEAR ENOUGH OF A CHANCE TO WARRANT
A MENTION JUST YET. STARTING THURSDAY...WE INTRODUCE SLIGHT CHANCE
POPS AS A BIT MORE MOISTURE IS FORECAST TO WORK NORTHWARD FROM THE
GULF COAST REGION. MEANWHILE...A PERSISTENT SOUTHWEST FLOW ALOFT
WILL GRADUALLY TURN NORTHWEST THURSDAY NIGHT INTO FRIDAY...WHICH
SHOULD ALLOW A FRONTAL BOUNDARY TO MOVE INTO THE REGION BY FRIDAY
NIGHT. AS A RESULT WE WILL CARRY LOW CHANCE POPS FOR CONVECTION
THURSDAY NIGHT THROUGH SATURDAY...THEN DRY IT OUT SATURDAY NIGHT
INTO SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 627 AM CDT SUN APR 29 2012
KEPT THE TERMINAL FORECASTS SIMPLE. STATIONARY FRONT FROM JUST
NORTH OF KPOF TO JUST SOUTH OF KOWB WILL SLOWLY LIFT NORTH THROUGH
THE FORECAST PERIOD. CONVECTIVE CHANCES TOO LOW TO CARRY IN THE
FORECAST AT THIS TIME. JUST SCT CU CLOUDS AND A FAIR AMOUNT OF
HIGH CLOUD COVER. SOME LIGHT FOG HAS FORMED JUST NORTH OF THE
FRONT EARLY THIS MORNING. WILL HAVE TO MONITOR THIS TREND
ESPECIALLY FOR KEVV AND KOWB.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1109 AM EDT SUN APR 29 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY WEATHER TODAY AND TONIGHT. A WARM
FRONT WILL APPROACH THE AREA FROM THE SOUTHWEST ON MONDAY, BRINGING
THE CHANCE OF THUNDERSTORMS. THE WARM FRONT WILL LIFT NORTH OF THE
AREA FOR THE MID-WEEK, WITH ABOVE NORMAL TEMPERATURES EXPECTED FOR
THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO INCREASE HIGH TEMPS
A FEW DEGREES ACROSS THE AREA.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE AXIS
CENTERED ACROSS THE WESTERN GREAT LAKES WITH THE UPPER OHIO VALLEY
IN A NORTHWESTERLY FLOW AHEAD OF THIS FEATURE. AT THE SURFACE, HIGH
PRESSURE EXTENDS FROM ONTARIO SOUTHEASTWARD ACROSS PENNSYLVANIA AND
INTO THE MID-ATLANTIC. THE 12Z KPIT SOUNDING INDICATES A DEEP LAYER
OF DRY AIR WITH SUBSIDENCE ALOFT. SAT IMAGERY CONFIRMS THIS WITH
CLEAR SKIES ASIDE FROM SOME PASSING CIRRUS.
THE MID-LEVEL RIDGE WILL MOVE INTO THE OHIO VALLEY TODAY AND ACROSS
THE AREA TONIGHT, ALLOWING FOR DRY WEATHER. HIGH PRESSURE WILL SHIFT
FROM ONTARIO INTO NY/EASTERN PA THROUGH THIS PERIOD, ALLOWING LIGHT
NORTHERLY WINDS TODAY TO SHIFT TO MORE SOUTHEASTERLY BY DAWN ON MONDAY.
SKIES WILL BE MOSTLY CLEAR TODAY, WITH CLOUD COVERAGE BEGINNING TO
INCREASE FROM THE SOUTH OVERNIGHT AS MOISTURE SPILLS ACROSS A
FRONTAL BOUNDARY TO THE SOUTH. TEMPS TODAY ARE CLOSEST TO THE
HRRR, WARMING TO NEAR NORMAL SEASONAL VALUES. LOWS TONIGHT ARE
CLOSER TO THE WARMER MET GUIDANCE.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT WARM FRONT WILL RETURN TO
REGION DURING THE DAY MONDAY AS SHORTWAVE RIDES MOVES ACROSS THE
GREAT LAKES. THIS WILL BRING AN INCREASING CHANCE FOR SHOWERS AND
STORMS DURING THE DAY. SURFACE LOW WILL MOVE TO LAKE ERIE MONDAY
NIGHT WITH COLD FRONT ENTERING THE REGION.
THE SURFACE LOW WILL PASS NORTH OF THE AREA MONDAY NIGHT, WITH
LIKELY POPS FORECAST ACROSS THE AREA. WITH THE WARM FRONT LIFTING
NORTH OF THE AREA, THE UPPER OHIO VALLEY WILL BE IN THE WARM
SECTOR TUESDAY AND WEDNESDAY. CHANCE POPS ARE FORECAST EACH DAY
WITH CONVECTION. UPPER LEVEL HEIGHTS WILL BE ON THE RISE THROUGH THE
PERIOD AS RIDGE DEVELOPS OFF THE CAROLINAS WITH ABOVE NORMAL
TEMPERATURES BY MID WEEK.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
LONG TERM FORECAST WAS BASED ON GFS/ECMWF ENSEMBLE MEANS AND
FEATURES THE FLATTENING OF BROAD ERN CONUS RIDGE AS THE WEEKEND
APPRCHES. ADJUSTMENTS WERE INCLUDED TO PCPN PROBABILITIES ON
THURSDAY AND FRIDAY TO ACCOUNT FOR EXPECTED FRONTAL POSITIONING.
SFC CDFNT IS STILL PROJECTED FOR A FRIDAY PASSAGE UNDER THIS
PATTERN...AND POPS WERE THUS REDUCED FOR THE WEEKEND.
WARM MIDWEEK TEMPERATURES SHOULD CONTINUE INTO THURSDAY WITH WARM
ADVECTION CONTINUING IN ADVANCE OF THE APPRCHG CDFNT. GIVEN THE
PROJECTED AMPLITUDE OF THE MID/UPR RIDGE...HAVE STAYED WITH THE
COOLER HPC GUIDANCE IN THAT TIME FRAME WHICH PROJECTS HIGHS
APPROXIMATELY 10 DEGREES ABOVE THE SEASONAL NORMALS.
THE AFOREMENTIONED RIDGE EROSION PROGNOSIS FOR THE WEEKEND IS NOT AS
DRAMATIC AS PREVIOUS SOLUTIONS...WITH EXCEPTION OF LATEST ECMWF
FORECAST WHICH HAS BEEN DISCOUNTED. TEMPERATURES WERE THUS FORECAST
CLOSER TO...BUT STILL A FEW DEGREES ABOVE THE NORMALS TO ACCOMPANY
THE REDUCED POPS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
SURFACE HIGH PRES WL SLIDE ACRS THE GREAT LAKES AND CONTINUE TO PUSH
DRIER AIR OVR THE UPR OH VALLEY REGION TDA. ALTHOUGH HIGH...AND MID
LVL CLDS WL BE ON THE INCRS THROUGH TNGT...VFR CONDITIONS CAN BE
EXPECTED WITH LGT NORTH WIND VEERING TO THE EAST THROUGH THE TAF PD.
BY MONDAY MRNG...SHRA/TSRA ARE ANTICIPATED WITH WARM...MOIST SURGE
OVR THE UPR OH REGION. MVFR RESTRICTION SHOULD BE EXPECTED IN THIS
CONVECTIVE ACTIVITY...WHICH MAY CONTINUE INTO THE AFTN DEPENDING ON
TIMING OF SHRTWV SUPPORT.
.OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
RESTRICTIONS IN SCT SHRA AND TSRA ARE POSSIBLE MONDAY NGT THROUGH
WEDNESDAY AS GREAT LAKES LOW PRES ADVECTS WARMTH AND MOISTURE ACROSS
THE REGION. MORE TSRA ARE ANTICIPATED FOR THURSDAY IN ASSOCIATION
WITH THE SYSTEMS CDFNT APPRCH.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BILLINGS MT
911 AM MDT SUN APR 29 2012
.SHORT TERM...VALID FOR TDY AND MON...
UPDATE TO FORECAST THIS MORNING TO INCREASE POPS OVER THE CENTRAL
ZONES. CLOSED UPPER LOW OVER WESTERN NORTH DAKOTA WAS CONTINUING
TO LIFT SLOWLY NORTHEAST THIS MORNING. MID LEVEL TROWAL WAS
CONTINUING TO WEAKEN AS IT SHIFTS EASTWARD. WATER VAPOR SATELLITE
WAS STILL INDICATING MID LEVEL MOISTURE OVER THE AREA AND AS
POINTED OUT BY THE MIDNIGHT SHIFT...WEAK PRESSURE ADVECTION AT
290 K ISENTROPIC WAS OCCURRING OVER CENTRAL MONTANA...BASED ON
THE RUC13 ANALYSIS. IN ADDITION...WEAK VORTICITY WAS ALSO
WRAPPING AROUND THE UPPER LOW ADDING ADDITIONAL LIFT OVER THE
AREA THIS MORNING. HAVE INCREASED POPS FOR THE REMAINDER OF THE
MORNING FOR COLUMBUS AND BILLINGS TO LIKELY. MODELS CONTINUE TO
INDICATE DRIER AIR MOVING IN FROM THE WEST AFTER 18Z AND CHANCE
OF PRECIPITATION WILL BECOME ISOLATED AT BEST FOR THE REST OF THE
DAY OVER THE WESTERN AND CENTRAL ZONES. PRECIPITATION CHANCES
ALSO DECREASING TO SCATTERED OVER SOUTHEAST MONTANA THIS
AFTERNOON AS THE STORM SYSTEM CONTINUES TO WEAKEN. TEMPERATURE
FORECAST CLOSE TO 12Z GUIDANCE AND WILL MAKE NO CHANGES. RICHMOND
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
MODELS WERE IN FAIR AGREEMENT THROUGH FRIDAY...BUT NOT SO MUCH
FROM SATURDAY ONWARD. THERE WERE EVEN SOME SMALL DIFFERENCES IN
THE TIME OF AGREEMENT. THESE DIFFERENCES WERE ON OVERALL STRENGTH
AND TIMING OF SHORTWAVES IN A BROAD TROUGH PROGGED FOR TUESDAY
AND WEDNESDAY. ENERGY OVER THE ALEUTIAN ISLANDS WILL DROP INTO
THE PACIFIC NORTHWEST ON MONDAY. THIS ENERGY WILL MOVE INTO
WESTERN MONTANA EARLY TUESDAY AND CARVE OUT A BROAD TROUGH OVER
THE NORTHERN ROCKIES. THIS TROUGH WILL REMAIN IN PLACE FOR A
COUPLE OF DAYS AS ONE CHUNK OF ENERGY MOVES NORTHEAST INTO SOUTH
CENTRAL CANADA WHILE ANOTHER WAVE DROPS INTO THE PACIFIC
NORTHWEST. THIS WILL KEEP THE FORECAST SOMEWHAT UNSETTLED WITH
THE MOUNTAINS RECEIVING THE BEST SHOT OF SHOWERS. HAVE LOWERED
HIGHS A COUPLE OF DEGREES TUESDAY AND WEDNESDAY WITH LOW MID
LEVEL HEIGHTS.
THE SECONDARY PIECE OF ENERGY MOVING INTO THE TROUGH MENTIONED
ABOVE EXITS THE AREA WEDNESDAY NIGHT WITH A SMALL SCALE RIDGE
MOVING IN THURSDAY. THIS WILL BE SHORT LIVED HOWEVER AS DEEPENING
SHORTWAVE FLOW ALOFT WILL ALLOW SEVERAL WAVES OF ENERGY AND
MOISTURE TO STREAM INTO THE FORECAST AREA. THE MOUNTAINS WILL
RECEIVE THE BULK OF THE PRECIPITATION CHANCES...BUT THE PLAINS
WILL ALSO GET SCATTERED POPS WITH LOW LEVEL NORTHERLY FLOW. THE
STRONGEST POP DAY WILL LIKELY BE ON SATURDAY AS THE WESTERN
TROUGH KICKS ACROSS THE AREA. NOW THE ECMWF DOES NOT SWING THE
TROUGH INTO THE AREA. THE ECMWF DROPS THE TROUGH SOUTH IN
SPLITTING FLOW AND CUTS THE SOUTHERN STREAM OFF IN NEVADA.
MONTANA WOULD GET UPPER DIVERGENCE FORCING ON SUNDAY...WITH
SATURDAY BEING RELATIVELY DRY. DID NOT CHANGE POPS MUCH FOR THE
WEEKEND AS NEED TO GET THESE MODEL DIFFERENCES RESOLED BEFORE
PUSHING IN THE WET OR DRY DIRECTION. WILL LEAVE IN LOW SCATTERED
POPS FOR NOW. TWH
&&
.AVIATION...
A BAND OF LIGHT RAIN ALONG AND EAST OF A KSHR-KBIL-KLWT LINE WILL
CONTINUE THIS MORNING AND SLOWLY MOVE EAST DURING THE AFTERNOON.
FREQUENT MVFR CONDITIONS WILL OCCUR WITHIN THE PRECIPITATION WITH
OCCASIONAL IFR CONDITIONS EXPECTED. THE PRECIPITATION WILL TAPER
OFF THROUGH THE MORNING WITH CONDITIONS IMPROVING TO MAINLY VFR
THIS AFTERNOON. THE MOUNTAINS WILL CONTINUE TO BE MAINLY OBSCURED
THROUGHOUT THE DAY. CLOUDS WILL CONTINUE TO DECREASE FROM WEST TO
EAST THIS AFTERNOON INTO TONIGHT WITH IMPROVING CONDITIONS.
HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 056 039/067 045/063 039/063 041/066 045/068 045/065
7/R 12/W 33/T 21/B 11/B 11/B 22/W
LVM 055 034/059 037/058 032/057 033/061 036/063 037/061
3/R 23/W 44/T 21/B 12/W 22/W 23/W
HDN 056 035/069 046/065 039/065 040/068 043/070 044/067
7/R 11/B 23/T 21/B 11/B 11/B 22/W
MLS 050 037/069 048/065 041/065 041/065 045/069 046/067
7/R 21/B 22/T 22/W 11/B 11/B 22/W
4BQ 050 034/069 048/066 040/065 040/067 044/070 044/067
6/O 11/B 23/T 21/B 11/B 11/B 23/W
BHK 048 034/067 047/064 040/063 040/064 044/068 043/067
7/R 21/B 22/T 22/W 11/B 11/B 23/W
SHR 053 033/065 042/062 036/062 037/065 040/068 040/064
4/R 11/B 23/T 21/B 11/B 11/B 23/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
835 AM CDT SUN APR 29 2012
.UPDATE...JUST STARTING TO GET A HANDLE ON TRENDS FOR TODAY...BUT
FIRST ORDER OF BUSINESS WAS UPDATING TO EXTEND COVERAGE OF FOG
WELL INTO THE MORNING HOURS...INCLUDING A MENTION OF PATCHY DENSE
FOG ACROSS A GOOD PERCENTAGE OF MAINLY THE CENTRAL/EASTERN CWA
BASED ON AUTOMATED OBS AND NDOR WEB CAMS. GLANCING AT BOUNDARY
LAYER RH PROGS FROM VARIOUS MODELS...LOW STRATUS AND FOG COULD BE
FAIRLY SLOW TO BURN OFF TODAY...ESPECIALLY ACROSS PARTS OF THE
SOUTHEAST 1/3 OR SO OF THE CWA. OBVIOUSLY THE LONGER FOG AND/OR
LOW STRATUS LINGERS...THE HARDER IT MAY BE TO REALIZE FORECAST
HIGHS IN THE MID-UPPER 60S...BUT NOT GOING TO MESS WITH INHERITED
TEMP FORECAST FOR AT LEAST A FEW MORE HOURS. ALSO NO CHANGES MADE
TO LOW-END AFTERNOON THUNDERSTORM CHANCES AT THIS TIME...ALTHOUGH
QUICK GLANCE AT 10Z HRRR AND 00Z 4KM WRF-NMM SUGGEST THE BEST
CHANCES WILL TARGET MAINLY THE WESTERN 1/3 OF THE CWA LATE THIS
AFTERNOON INTO THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 624 AM CDT SUN APR 29 2012/
AVIATION...12Z TAF. SOME LIGHT FOG/MIST HAS SPREAD INTO THE KGRI
TERMINAL AREA AND IS RESTRICTING VISIBILITIES. THE VISIBILITY
SHOULD IMPROVE AS THE LOWER STRATUS MOVES INTO THE AREA IN THE
NEXT HOUR OR SO. EITHER WAY THERE WILL BE IFR CONDITIONS ARE
EXPECTED. BY MID DAY VFR CONDITIONS ARE EXPECTED AGAIN AS THE
CLOUDS RECEDE FROM THE AREA. LATE TONIGHT EXPECT IFR CONDITIONS
AGAIN WITH LOW LEVEL MOISTURE AND LIGHT WINDS.
PREV DISCUSSION... /ISSUED 323 AM CDT SUN APR 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. SMALL AREA OF LIGHT
SHOWERS/SPRINKLES OVER SOUTHWEST KS EARLY THIS MORNING SEEMS TO BE
ASSOCIATED WITH THE UPPER LEVEL JET DYNAMICS/DIFFLUENCE. DEPENDING
ON THE MODEL...ONE BRINGS THIS AREA OF SPRINKLES INTO OUR CWA
AROUND SUNRISE...THE OTHERS SUGGEST IT WILL STAY SOUTH. ALL THE
MODELS SHOW OUR CWA IN A RELATIVELY RAIN FREE AREA THROUGH TUESDAY
AFTERNOON. SEVERAL WEAK WAVES MOVING OVER THE AREA...SO EVEN
THOUGH CHANCES OF RAIN ARE LOW...THERE IS A CHANCE NONE THE LESS.
IN SHORT...TWEAKED PROBABILITY OF PRECIP AND A TEMP GRID HERE AND
THERE...BUT ON GOING FORECAST LOOKS FINE FOR NOW.
WILL HAVE TO WATCH FOR SOME POTENTIAL SEVERE WEATHER/THUNDERSTORM
DEVELOPMENT TUESDAY NIGHT THROUGH WEDNESDAY MORNING AS THERE IS
SOME INDICATION OF RAPID DESTABILIZATION OF THE ATMOSPHERE AS A
WARM FRONT MOVES INTO THE AREA. WILL NOT MENTION AT THIS TIME AS
CONFIDENCE IS LOW ALL THE INGREDIENTS WILL COME TOGETHER AS FORECAST.
MILD TEMPS TO CONTINUE THROUGH THE PERIOD. TODAY PROBABLY THE
COOLEST DAY THEN WARMING TO 10 TO 15 DEGREES ABOVE NORMAL BY MID WEEK.
LONG TERM...12Z WEDNESDAY THROUGH SATURDAY. MAIN FORECAST CONCERNS
WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS AND TEMPERATURES.
NEARLY ZONAL FLOW CONTINUES THROUGH THE PERIOD AND WITH IT THERE ARE
SEVERAL WAVES THAT MOVE THROUGH THE FLOW. MODELS CONTINUE TO HAVE
MINOR DIFFERENCES IN THE TIMING OF THESE WEAK WAVES AND THE SURFACE
SYSTEMS THAT MOVE THROUGH. THE LATEST RUNS OF THE MODELS HAVE A
SURFACE LOW AND COLD FRONT MOVING THROUGH WEDNESDAY NIGHT AND HAVE
KEPT A CHANCE FOR SHOWERS AND THUNDERSTORMS. WITHOUT A DEFINED
SURFACE BOUNDARY FOR THURSDAY THROUGH FRIDAY NIGHT HAVE KEPT DRY
CONDITIONS ACROSS THE AREA. BOTH THE GFS AND ECMWF DEVELOP ANOTHER
SURFACE LOW FOR SATURDAY MAINLY TO THE WEST OF THE FORECAST AREA.
WILL HAVE SOME CHANCES IN THE WEST/NORTHWEST. TEMPERATURES SHOULD BE
RATHER MILD WITH READINGS ABOVE NORMAL FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
700 AM EDT SUN APR 29 2012
.SYNOPSIS...
HIGH PRESSURE OVER EASTERN GREAT LAKES AND NEW ENGLAND WILL MOVE
OFFSHORE TODAY....ALLOWING A NEARLY STATIONARY FRONT OVER SOUTH
CAROLINA TO RETURN NORTH AS A WARM FRONT. A COLD FRONT WILL MOVE
BACK SOUTH ACROSS NORTH CAROLINA THIS AFTERNOON AND EVENING.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 305 AM SUNDAY...
MOSTLY A TEMPERATURE FORECAST TODAY...AND WITH LOW FORECASTER
CONFIDENCE BASED ON UNCERTAINTY IN THE EROSION OF THE WIDESPREAD
STRATUS AND POOR MODEL PERFORMANCE WITH THE RESIDUAL WEDGE AIRMASS
OVER THE AREA. THE WEDGE BOUNDARY REMAINS STATIONARY OVER SC THIS
MORNING...WITH HIGH PRESSURE OVER EASTERN CANADA BEGINNING TO NOSE
SOUTH ACROSS THE GREAT LAKES TOWARD THE OUR AREA. THE STRATUS
LAYER CONTINUES BE RATHER THIN...ONLY A FEW HUNDRED FEET
DEEP...BUT THERE HAS BEEN NO SIGNIFICANT MECHANISM TO HELP ERODE
THE CLOUDS. MODELS MAY ONCE AGAIN BE TOO AGGRESSIVE IN SHOWING
SOUTHWESTERLY LOW LEVEL FLOW DEVELOPING THIS MORNING...WHICH WOULD
LEAD TO FASTER SCATTERING OF CLOUD BY MID-MORNING. FORECAST
1000-850MB THICKNESSES RANGE FROM 1360M IN THE NORTHEAST TO NEAR
1400M IN THE SOUTHWEST. 1400M WOULD SUPPORT HIGHS IN THE MID 80S IN
THE SOUTHWEST UNDER FULL SUN...AND THE MAV GUIDANCE EVEN HAS
VALUES AS HIGH AS 88 OVER THE SOUTHERN PIEDMONT. HOWEVER...GIVEN
THAT THE NAM/GFS HAVE STRUGGLED SO MUCH WITH THIS WEDGE AIRMASS
OVER THE PAST 24 HOURS...AND ALSO THAT RECENT HRRR RUNS SHOW
STRATUS LINGERING THROUGH LATER MORNING...CONFIDENCE IS JUST NOT
HIGH ENOUGH TO FORECAST MID 80S IN THE SOUTHWEST. WE WILL KEEP
FORECAST HIGHS IN THE UPPER 60S IN THE NORTHEAST WHERE STRATUS
WILL LINGER THROUGH MUCH OF THE DAY...TO AROUND 80 IN THE
SOUTHWEST.
IF THE CLOUDS DO BREAK BY MIDDAY AND LOW TO MID 80S CAN BE
REACHED...STEEP MID LEVEL LAPSE RATES AROUND 7-7.5 C/KM WOULD HELP
TO SUPPORT 500-1000 J/KG OF MLCAPE SOUTHERN PIEDMONT.B
HOWEVER...FORECAST SOUNDINGS ALSO SHOW A DECENT CAP JUST ABOVE
800MB. THE MID LEVEL RIDGE AXIS THAT IS CURRENTLY WEST OF THE
MOUNTAINS WILL BE INCHING EASTWARD...AND LOW LEVEL FORCING WILL BE
WEAK TO NON-EXISTENT...SO WE WILL LEAVE THE FORECAST DRY FOR TODAY.
TONIGHT...SURFACE HIGH PRESSURE WILL BUILD OVER THE GREAT LAKES AND
EXTEND SOUTHEAST INTO VA AND NC. THIS WILL HELP SUPPLY ANOTHER SHOT
OF COOL AND MOIST NORTHEASTERLY LOW LEVEL FLOW...WITH STRATUS LIKELY
TO SURGE BACK IN ACROSS THE AREA. WITH THE MID LEVEL RIDGE BUILDING
OVERHEAD AND INCREASING MOISTURE BELOW THE SUBSIDENCE
INVERSION...FORECAST SOUNDINGS SHOW QUITE A BIT OF VEERING LOW
LEVEL WINDS AND WARM ADVECTION OVERNIGHT...WHICH MAY LEAD TO PATCHY
LIGHT RAIN AND/OR DRIZZLE. LOWS IN THE MID 50S NORTHEAST TO AROUND
60 SOUTHWEST.
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM...
HIGH PRESSURE SURFACE AND ALOFT LOCATED TO OUR SOUTH AT SUNRISE
TUESDAY. A SUBTLE SHORT WAVE IS SURPRISINGLY DEPICTED CONSISTENTLY
ACROSS SEVERAL MODELS FOR THE MID ATLANTIC REGION DURING THE DAY...
INDUCING WEAK SURFACE TROUGHING OVER VIRGINIA AND NORTH CAROLINA.
LOW LEVEL CONVERGENCE IS QUITE WEAK BUT AFTERNOON INSTABILITY...
CAPE AND MID LEVEL TEMPERATURE LAPSE RATES ALL INDICATE CONVECTION
IS A POSSIBILITY. WITH SUCH WEAK FORCING... WILL KEEP CHANCES FOR
THUNDER AT SLIGHT AND IN THE AFTERNOON.
MODEL CONSENSUS ON 1000 TO 850 MILLIBAR THICKNESS TUESDAY AFTERNOON
IN LINE WITH CLIMATOLOGICAL NORMALS FOR EARLY JUNE. CIRRUS CLOUDS
COULD IMPACT AFTERNOON TEMPERATURES... BUT FOR NOW WILL MINIMALIZE
THIS AND FORECAST HIGH TEMPERATURES IN THE LOWER 80S NORTHWEST AND
MID 80S ELSEWHERE.
ANY AFTERNOON CONVECTION SHOULD NOT PERSIST PAST LATE EVENING
TUESDAY NIGHT. LOW LEVEL THICKNESSES MORE TYPICAL OF EARLY JUNE
PERSIST. PRECIPITABLE WATERS IN EXCESS OF 1.25 INCHES AND A LIGHT
SOUTHWEST BREEZE WITH PERIODS OF CALM WILL ALLOW TEMPERATURES TO
FALL NO LOWER THAN THE LOWER 60S BY SUNRISE WEDNESDAY.
LOW LEVEL THICKNESSES RISE FIVE TO TEN METERS WEDNESDAY AFTERNOON
OVER THE PREVIOUS DAY AND MIXING HEIGHTS WILL PERHAPS REACH 7000
FEET. MOISTURE IS SOMEWHAT LIMITED... ESPECIALLY TO THE SOUTH. A
WEAK BOUNDARY LOCATED NEAR OR NORTH OF HIGHWAY 64 WILL POTENTIALLY
BE A FOCUS FOR CONVECTION. DUE TO LIMITED MOISTURE WILL KEEP CHANCES
AT SLIGHT FOR MID TO LATE AFTERNOON. DAMAGING DOWNBURST WINDS WILL
BE A RISK DUE TO EVAPORATIVELY COOLED DOWNDRAFTS IF THE ABOVE
SCENARIO HOLDS UP... BUT WITH COVERAGE LIMITED TO ABSENT... NO PLANS
TO MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. AFTERNOON
THICKNESSES MORE TYPICAL OF MID JULY ARE FORECAST. HIGH TEMPERATURES
MOSTLY MID 80S.
IN SPITE OF THE BOUNDARY IN THE NORTH... ANY CONVECTION LOOKS TO BE
SHORT LIVED ONCE THE HEATING OF THE DAY IS LOST. LOW TEMPERATURES
SHOULD FALL NO LOWER THAN THE LOW TO MID 60S AS 1000 TO 850 MILLIBAR
THICKNESSES REMAIN ABOVE 1400 METERS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 AM...
THE AIR MASS DRYS A BIT THURSDAY IN LIGHT WEST FLOW AS THE UPPER
LEVEL RIDGE OVER THE EASTERN UNITED STATES STRENGTHENS SLIGHTLY.
LATE AFTERNOON CONVECTION NOT IMPOSSIBLE BUT CHANCES LOOK LESS THAN
SLIGHT AT THIS TIME... WITH THE SCENARIO REPEATING FOR FRIDAY AS
WELL. CONTINUE TO FAVOR THE MORE PERSISTENT RIDGE OF THE ECMWF MODEL
THOUGH THE ECMWF DOES RETROGRADE THE RIDGE TO THE MIDWEST THURSDAY
NIGHT AND INTO THE WEEKEND. THIS SHOULD ALLOW AFTERNOON TEMPERATURES
TO SLIP A BIT SATURDAY AND INCREASE AFTERNOON RAIN CHANCES FOR
SATURDAY AFTERNOON.
WELL ABOVE NORMAL TEMPERATURES TO CONTINUE FOR THIS FORECAST PERIOD.
MID TO UPPER 80S THURSDAY AND FRIDAY... LOW TO MID 80S SATURDAY. LOW
TEMPERATURES IN THE LOW TO MID 60S.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 700 AM SUNDAY...
MVFR CEILINGS ARE PREDOMINATE ACROSS ALL OF CENTRAL NC THIS MORNING
AS LOW LEVEL MOISTURE REMAIN LOCKED IN PLACE NORTH OF STATIONARY
FRONT OVER SC. THE EXCEPTION IS OVER THE TRIAD WHERE DRIER AIR HAS
CAUSED THE LOW CLOUDS TO BREAK. MODELS INDICATE THE SHALLOW LAYER OF
LOW LEVEL MOISTURE WILL CONTINUE TO ERODE WITH SOUTH-SOUTHWESTERLY
LOW TO MID LEVEL FLOW TODAY. HOWEVER...MODELS MAY BE ERODING
STRATUS FROM THE SOUTH AND WEST TOO QUICKLY...AS THEY OFTEN DO....SO
MVFR CEILINGS MAY PERSIST WELL INTO THE AFTERNOON FROM KRDU TO
KRWI. WINDS WILL GENERALLY BE LIGHT AND VARIABLE FOR A GOOD PORTION
OF THE DAY BUT WILL BECOME EAST-NORTHEASTERLY AGAIN THIS EVENING AS
HIGH PRESSURE OVER THE GREAT LAKES PUSHES ANOTHER COLD FRONT INTO
THE AREA FROM THE NORTH. THIS COOL STABLE FLOW WILL BRING STRATUS
BACK ACROSS THE AREA ONCE AGAIN TONIGHT AND MONDAY
MORNING...POTENTIALLY WITH PATCHY LIGHT RAIN AT TIMES. -SMITH
OUTLOOK...
MVFR CEILINGS MAY PERSIST INTO THE DAY ON MONDAY...THOUGH AN OVERALL
DRYING TREND IS EXPECTED THROUGH MID WEEK AS AN UPPER LEVEL RIDGE
SETTLES OVER THE REGION. AFTERNOON SHOWERS/STORMS MAY BE POSSIBLE BY
WEDNESDAY BUT VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR MUCH OF THE
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...SMITH/99
LONG TERM...99
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1044 AM CDT SUN APR 29 2012
.UPDATE...
UPPER-LEVEL CLOUDS CONTINUE TO WORK INTO CWA...THOUGH HIGHS SHOULD
STILL REACH NEAR THEIR SEASONAL VALUES DESPITE DAYTIME HEATING BEING
LIMITED BY CIRRUS. INHERITED GRIDS APPEAR TO BE ON TRACK...ONLY
SLIGHTLY ADJUSTED TO ACCOUNT FOR LATEST OBS TRENDS.
MAIN CONCERN IS SAID CLOUDS AND THEIR INFLUENCE ON HIGHS. BUT GIVEN
CURRENT TEMPS...AND HOW MUCH FILTERED SUNSHINE IS COMING THROUGH...NO
SIGNIFICANT CHANGES WERE MADE WITH HIGHS. SHOWERS ARE STILL ANTICIPATED
TO NOT IMPACT THE CWA UNTIL 00Z MONDAY AT THE EARLIEST. LATEST MODEL
GUIDANCE...INCLUDING HI-RES HRRR AND LOCAL WRF...AGREES WITH PREVIOUS
FCST IN REGARD TO TIMING.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS EXPECTED INTO THE EARLY EVENING HOURS...BUT THEN
THINGS DETERIORATE TONIGHT. LOOK FOR HIGH CLOUDS AND UNRESTRICTED
VSBYS THROUGH ABOUT 01Z THIS EVENING. THEN AN IMPRESSIVE SURGE OF
MOISTURE WILL HEAD NORTH INTO SOUTHERN WISCONSIN THIS EVENING ON
AN INCREASING LOW LEVEL JET AHEAD OF AN 850MB LOW PRESSURE SYSTEM
MOVING ACROSS IOWA. A SURFACE WARM FRONT WILL ARRIVE LATE TONIGHT
AS WELL. RAIN WILL QUICKLY OVERSPREAD THE AREA THIS EVENING WITH
CIGS DROPPING TO MVFR BY AROUND 05-06Z AND LIKELY TO IFR LEVELS
AFTER 09Z. THERE IS SMALL CHANCE FOR THUNDERSTORMS WITH THIS
EVENT...BUT IT ISN/T THE MAIN CONCERN. THE RAIN SHOULD BE EXITING
EASTERN WISCONSIN BY AROUND 12Z. BUT A BAGGY PRESSURE PATTERN WITH
AN EXITING WARM FRONT TO THE EAST WILL LIKELY PRECLUDE ANY GOOD
SCOURING OF THE LOW CLOUDS UNTIL ABOUT MID DAY ON MONDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE FCST TRENDS...EHT
UPDATE AVIATION...DAVIS
TODAY/TONIGHT AND AVIATION/MARINE...MBK
MONDAY THROUGH SATURDAY...MRC
AREA FORECAST DISCUSSION
NWS MIAMI FL
225 PM EDT SUN APR 29 2012
.DISCUSSION...WATER VAPOR CONTINUES TO SHOW WELL DEFINED MID LEVEL
TROUGH OVER THE WESTERN CARIBBEAN EXTENDING NORTHEAST INTO THE FL
STRAITS. AT THE SFC, A BROAD TROUGH ALSO STRETCHES ACROSS ROUGHLY
THE SAME AREA WITH VISIBLE SATELLITE INDICATING BROAD CIRCULATION
AROUND THESE TWO FEATURES WITH A RICH PLUME OF TROPICAL MOISTURE
FEED ACROSS CUBA, FL STRAITS AND S FL. THE 12Z MFL SOUNDING
ALTHOUGH CONTAMINATED BY CONVECTION AT LAUNCH TIME SHOWS THE DEEP
EASTERLY FLOW.
LOOKING AT THE VERY SHORT TERM, THE HRRR WHICH HAS BEEN DOING
REMARKABLY WELL THE PAST COUPLE OF DAYS SHOWS A DECREASING TREND
THROUGH THIS AFTERNOON BUT THEN A REGENERATION OFF THE SE CST AFT
03Z THIS EVENING WHICH IS AT THE END OF ITS CURRENT FCST CYCLE. BOTH
THE GFS AND NAM PERSIST IN SHOWING A DEEPENING SFC TROUGH OVER THE FL
KEYS FROM LATE THIS AFTERNOON INTO THIS EVENING AND MOVING IT WEST
INTO THE SE GULF BY LATE MONDAY. THEY HAVE HOWEVER BOTH SCALED BACK
THE STRENGTH AND NO LONGER SHOW A CLOSED CIRCULATION SO WILL STICK
CLOSER TO THE NAM SPEEDS WHICH IS THE WEAKER OF THE TWO MODELS. THE
LONGER RANGE MODELS STILL DIVERGE AS TO THE EVOLUTION OF THESE
SYSTEMS THROUGH THE NEXT 24 TO 36 HOURS BUT ALL AGREE TO A CERTAIN
DEGREE THAT THE BAND OF MOISTURE WILL MOVE VERY LITTLE THROUGH
THIS TIME FRAME. RAINFALL ACCUMULATION IS ALSO TROUBLESOME WITH
THE NAM NOT SHOWING MUCH AFT 00Z THIS EVENING AND ALTHOUGH THERE
HAS BEEN SOME DECREASE IN THE OVERALL REFLECTIVITY FROM THE
REGIONAL RADARS, THE TROPICAL FEED WILL CONTINUE AND THUS THAT
SOLUTION SEEMS UNREALISTIC. THE GFS SEEMS TO BE SUFFERING FROM
CONVECTIVE FEEDBACK AS IT IS SHOWING A BULLS EYE 12 HOUR TOTAL
ENDING AT 18Z MONDAY OF IN EXCESS OF 8 INCHES ACROSS NORTHERN
MIAMI-DADE COUNTY. OF COURSE, GIVEN THESE HISTORIC PWAT ANOMALIES
FOR LATE APRIL THIS SOLUTION CANNOT BE TOTALLY RULED OUT HOWEVER
AND SOMEWHERE FROM BROWARD TO MIAMI- DADE COUNTIES MAY INDEED APPROACH
8 INCHES OR EVEN SLIGHTLY HIGHER BY LATE MONDAY WITH THE GREATEST
COASTAL CONVERGENCE LIKELY OCCURRING AT LOW LEVELS ALONG AND NEAR
THE SOUTHEAST COAST LATE TONIGHT THROUGH EARLY MONDAY. THE ECMWF
IS A MIDDLE OF THE ROAD APPROACH. SO WITH ALL OF THIS BEING SAID,
THE FLOOD WATCH WILL CONTINUE THROUGH MONDAY EVENING FOR THE EAST
COASTAL REGION.
HIGH PRESSURE WILL REMAIN TO THE NORTHEAST OVER THE WESTERN ATLANTIC
WITH THE PRESSURE GRADIENT REMAINING TIGHT SO STRONG COASTAL
CONVERGENCE MAY AGAIN SET UP MONDAY NIGHT INTO EARLY TUESDAY AS THE
HIGH MOISTURE REMAINS ACROSS THE AREA. THE ECMWF HAS COME MORE IN
LINE WITH THE GFS AND SHOWING THE DEEP MOISTURE REMAINING IN PLACE
THROUGH THE END OF THIS WEEK SO RAIN CHANCES WILL CONTINUE WITH THE
HIGHEST CHANCES FOR THE EAST COAST.
&&
.MARINE...DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
&&
.FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL
MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 80 73 82 / 60 60 40 50
FORT LAUDERDALE 72 79 74 83 / 80 70 50 50
MIAMI 70 80 72 83 / 80 70 50 50
NAPLES 68 82 70 86 / 40 50 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH MONDAY EVENING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
215 PM EDT SUN APR 29 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING NORTHERN STREAM FLOW
CARVING OUT A LONGWAVE TROUGH INTO THE FOUR-CORNERS REGION AROUND A
LARGE CUTOFF LOW SPINNING OVER THE HIGH PLAINS. SHORTWAVE ENERGY
EJECTING EASTWARD FROM THE INTER-MOUNTAIN WEST OVER THE CENTRAL
PLAINS IS HELPING TO FORCE A LARGE AREA OF SHOWERS AND STORMS
ACROSS THE MIDDLE MS VALLEY. NORTHERN STREAM FLOW THEN RIDGES
NORTHWARD INTO THE GREAT LAKES BEFORE CARVING OUT ANOTHER TROUGH
OVER THE NORTHEASTERN STATES. CLOSER TO HOME...OUR FORECAST AREA IS
WEDGED BETWEEN UPPER LEVEL RIDGING OVER THE NORTHERN GULF COAST/SE
STATES...AND AN UPPER LEVEL DISTURBANCE FROM THE NW CARRIBEAN SEA TO
THE BAHAMAS. THIS ENERGY IS FORCING A LARGE AREA OF RAINFALL/THUNDER
OVER THE FAR SOUTHERN FL PENINSULA...FL STRAITS AND BAHAMAS. THE
DEEP COLUMN MOISTURE CONTINUES TO TRY AND MOVE NORTHWARD...BUT FOR
NOW IS STILL CONFINED TO AREAS SOUTH OF TAMPA BAY. ALTHOUGH THE 12Z
KTBW SOUNDING SHOWS SOME MOISTENING OVER THE PAST 24 HOURS WITH A PW
VALUE UP TO 1.25"...MIAMI`S KMFL PROFILE IS MUCH MORE MOIST WITH AN
ESSENTIALLY SATURATED COLUMN BELOW 500MB AND A PW VALUE OVER 2".
AT THE SURFACE...
FORECAST AREA REMAINS IN BETWEEN A RIDGE OF HIGH PRESSURE EXTENDING
FROM OFF THE SE COAST WESTWARD ALONG OR JUST NORTH OF THE I-10
CORRIDOR...AND A DEVELOPING LOW/INVERTED TROUGH OVER THE FL STRAITS.
LOW LEVEL FLOW BETWEEN THESE TWO FEATURES IS PROVIDING A LIGHT TO
MODERATE EASTERLY BREEZE.
&&
.SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
REST OF THIS AFTERNOON/EARLY EVENING...UPPER LEVEL SYNOPTIC SUPPORT
AND LOW LEVEL FOCUS FOR ASCENT WILL BE MAINTAINED OVER THE SOUTHERN
THIRD OF THE PENINSULA KEEPING A STEADY SUPPLY OF MOISTURE/SHOWERS
MOVING ASHORE (GENERALLY SOUTH OF A LINE FROM FORT MYERS TO WEST
PALM BEACH). SEEING SOME SCT CONVECTION DEVELOP INTO OUR SOUTHERN
ZONES THIS AFTERNOON DUE TO DIFFERENTIAL HEATING AND THE SYNOPTIC
SUPPORT ALOFT. FURTHER NORTH TOWARD THE TAMPA BAY REGION AND NATURE
COAST...THE INFLUENCE/SUPPRESSION FROM THE UPPER RIDGE SHOULD BE
MORE DOMINANT AND KEEP ANY AFTERNOON/EVENING SHOWER ACTIVITY VERY
ISOLATED (IF ANY). RAIN CHANCES WILL RANGE FROM THE HIGH END
CHANCE/LIKELY OVER THE FAR SOUTH...TO SLIGHT/CHANCE/CHANCE FOR
SARASOTA/MANATEE/HARDEE/DE SOTO...AND HIGHLANDS COUNTIES. FINALLY
SILENT 10% OR LESS RAIN CHANCES FROM PINELLAS/HILLSBOROUGH/POLK
COUNTIES NORTHWARD. WARMEST TEMPERATURES WILL ALSO BE OVER THE
NORTHERN ZONES WHERE MORE INSULATION/DEEP LAYER SUPPRESSION HAS
ALLOWED AFTERNOON HIGHS INTO THE UPPER 80S TO NEAR 90 AWAY FROM THE
COAST. THE THICKER CLOUDS TO THE SOUTH ARE HOLDING TEMPS IN THE
UPPER 70S DOWN TOWARD CHARLOTTE AND LEE COUNTIES.
MORE OF THE SAME OVERNIGHT. DIURNALLY FORCED SHOWERS FROM MANATEE TO
HIGHLAND COUNTIES WILL DISSIPATE WITH THE SETTING OF THE SUNSET.
ANY LINGERING SHOWER ACTIVITY WILL THEN BE CONFINED TO MAINLY LEE
AND CHARLOTTE COUNTIES. TEMPS WILL BE WARM (MID 60S TO LOW 70S) DUE
TO ABUNDANT LOW LEVEL MOISTURE STREAMING WESTWARD ACROSS THE
PENINSULA FROM THE ATLANTIC.
MONDAY THROUGH TUESDAY...
OVERALL SYNOPTIC PATTERN CHANGES LITTLE THROUGH THE REMAINDER OF THE
SHORT TERM PERIOD WITH THE SUBTROPICAL RIDGE AXIS HOLDING IN PLACE
TO OUR NORTH AND A SLOWLY WEAKENING AREA OF LOW PRESSURE MIGRATING
WESTWARD FROM THE FLORIDA STRAITS TO THE SOUTH-CENTRAL GULF OF
MEXICO. BEST CHANCES FOR ORGANIZED SHOWERS WILL REMAIN OVER THE FAR
SOUTHERN ZONES OF LEE AND CHARLOTTE IN CLOSER PROXIMITY TO THE UPPER
LEVEL SYNOPTIC SUPPORT AND LOW LEVEL FOCUS OF THE SURFACE TROUGH.
ONLY ISOLATED AFTERNOON CONVECTION (AT BEST) FURTHER NORTH FOR THE
REMAINDER OF THE FORECAST AREA UNDER INCREASING SUPPRESSION FROM THE
UPPER RIDGE. TEMPERATURES AT OR ABOVE NORMAL THROUGH THE PERIOD.
GREATEST DAYTIME INSULATION WILL OCCUR OVER THE CENTRAL AND NORTHERN
ZONES WHERE DAYTIME TEMPS WILL REACH WELL INTO THE 80S.
&&
.LONG TERM (WEDNESDAY THROUGH NEXT SUNDAY)...
THE GLOBAL MODELS GENERALLY AGREE THAT THE AREA REMAINS BETWEEN AN
UPPER LEVEL RIDGE TO THE NORTH AND TROUGHINESS TO THE SOUTH OR
SOUTHWEST...BUT THEY CONTINUE WITH SOME MINOR LOCATION AND TIMING
DIFFERENCES. AT THE SURFACE THERE IS BETTER CONSENSUS THAT HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGES WEST...ALONG THE GULF
COAST...WITH A SLOWLY RELAXING GRADIENT. THIS PATTERN WILL KEEP THE
AREA IN EASTERLY TO SE LOW LEVEL FLOW...INITIALLY ROBUST BUT
SLACKENING ENOUGH BY THE WEEKEND TO ALLOW SEA BREEZE
CIRCULATIONS...WITH A MOIST AND SOMEWHAT UNSTABLE AIRMASS. THE
FORECAST WILL STAY PARTLY CLOUDY WITH ONLY A SLIGHT CHANCE OF
SHOWERS OR STORMS...BELOW THE MEX GUIDANCE AND CLOSER TO CLIMO.
TEMPERATURES WILL RUN JUST ON THE WARM SIDE OF NORMAL...BY UP TO
A COUPLE OF DEGREES AT TIMES.
&&
.AVIATION...
VFR CIGS FROM TPA-PGD AROUND 250. SCT SHOWERS MOVING ACROSS THE
SOUTHERN INTERIOR PUSHING TO THE WEST WILL CREATE A CHANCE OF
SHOWERS FROM SRQ SOUTH TO FMY/RSW THROUGH THE REMAINDER OF THE
AFTERNOON WITH LCL MVFR CIGS/VSBYS. LOSS OF DAYTIME HEATING SHOULD
DECREASE SHOWER ACTIVITY AFTER SUNSET. BULK OF RAIN SHOULD REMAIN
JUST SOUTH AND EAST OF THE AREA.
&&
.MARINE...
THE LOCAL GRADIENT WILL TIGHTEN OVER THE FORECAST WATERS INTO
TONIGHT BETWEEN A RIDGE OF HIGH PRESSURE TO OUR NORTH AND A SURFACE
TROUGH OVER THE FLORIDA STRAITS. WINDS WILL INCREASE TO ADVISORY
LEVELS THIS EVENING OVER THE SOUTHERN THIRD OF THE MARINE
AREA...WITH PERIODS OF CAUTIONARY WINDS FURTHER TO THE NORTH. THIS
GENERAL PATTERN WILL PERSIST THROUGH THE EARLY PORTION OF THE WORK
WEEK WITH THE POTENTIAL FOR PERIODS OF CAUTIONARY TO ADVISORY LEVEL
WINDS AND SEAS. LATE IN THE WEEK THE GRADIENT IS EXPECTED TO
GRADUALLY RELAX AND ALLOW WINDS AND SEAS OVER THE EASTERN GULF TO
SUBSIDE.
&&
.FIRE WEATHER...
EASTERLY FLOW BETWEEN HIGH PRESSURE TO OUR NORTH AND AN AREA OF LOW
PRESSURE OVER THE FLORIDA STRAITS WILL CONTINUE TO SUPPLY THE REGION
WITH ABUNDANT LOW LEVEL MOISTURE THROUGH AT LEAST TUESDAY. RELATIVE
HUMIDITY IS EXPECTED TO REMAIN GENERALLY ABOVE CRITICAL LEVELS THE
NEXT SEVERAL DAYS...AND NO SIGNIFICANT FIRE WEATHER CONCERNS ARE
FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 70 87 71 86 / 10 10 5 20
FMY 68 83 69 87 / 30 30 25 35
GIF 66 87 68 87 / 10 10 5 15
SRQ 68 86 68 87 / 10 10 10 20
BKV 65 89 65 88 / 5 5 5 10
SPG 71 83 73 82 / 10 10 5 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-
BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
AVIATION/FIRE WEATHER...OGLESBY
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
632 PM EDT SUN APR 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 352 PM EDT SUN APR 29 2012
A BROAD QUASI ZONAL TO SOUTHWEST FLOW WILL MAINTAIN ITSELF OVER
MOST OF THE NEXT WEEK...WITH SEVERAL FRONTAL WAVES AND THUS
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS PRESENTING THEMSELVES
ACROSS CENTRAL INDIANA. THIS SOUTHWEST FLOW WILL ALSO ALLOW
TEMPERATURES TO BE SEASONABLY WARM FOR MUCH OF THE NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCI FOR TONIGHT ARE POPS AND THUNDER CHANCES. MODELS ARE IN
GENERAL AGREEMENT ON LARGE SCALE FEATURES...BUT LEANED TOWARD NAM
AS OTHER MODELS APPEAR TO BE TOO WET BASED ON CURRENT TRENDS.
WARM FRONT SHOULD GRADUALLY PUSH NORTHWARD TONIGHT...AS A WEAK
SURFACE LOW MOVES OUT OF THE CENTRAL PLAINS. MOST GUIDANCE
APPEARED A BIT TOO AGGRESSIVE ON PRECIP WHEN MUCH OF THE
CONVECTION TO OUR WEST HAS STRUGGLED TO MAKE IT EASTWARD TODAY.
RAPID REFRESH AND RUC DEPICT BEST CHANCES OF PRECIP TONIGHT ACROSS
OUR NORTHWEST...AND CONSENSUS APPROACH TEMPERED SLIGHTLY DEPICTS
THIS WELL. INSTABILITY IS THERE BUT MINIMAL...AND BASED ON SREF
THUNDER PROBS HAVE GONE WITH ISOLATED THUNDER MENTION RATHER THAN
STRAIGHT THUNDERSTORM FORECAST. DID GO WITH CHANCE THUNDER IN THE
NORTHWEST LATE WHERE PROBABILTIES ARE A BIT HIGHER.
CONSENSUS APPROACH ON TEMPS AGREES WELL WITH UPSTREAM MINS FROM
LAST NIGHT...AND WILL STICK CLOSE TO THIS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCUS REMAINS PRECIP CHANCES THROUGHOUT...WITH BOUNDARY REMAINING
IN THE AREA IN ONE FORM OR ANOTHER AND ONE OR MORE VERY SUBTLE
WAVES PERHAPS AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. POPS
APPEARED A BIT HIGH IN PLACES...BUT NOT BY MUCH...GIVEN THE LACK
OF SIGNIFICANT UPPER LEVEL SUPPORT THROUGH THE FIRST PART OF THE
WEEK. HOWEVER...EXPECT THAT MESOSCALE INFLUENCES WILL HELP MAKE UP
FOR THIS. LEANED HEAVILY ON SREF THUNDER PROBS AND BOUNDARY
POSITION FOR DELINEATING BETWEEN WHERE TO FORECAST STRAIGHT
THUNDERSTORMS AND WHERE TO GO MORE SHOWERS WITH ISOLATED THUNDER
MENTION.
SLIGHT RISK FOR TOMORROW AND SEE TEXT FOR TUESDAY APPEAR
REASONABLE BASED ON MODEL CAPE/SHEAR PROFILES. IN SOMEWHAT TYPICAL
FASHION...AFTERNOON AND EARLY EVENING WOULD BE PREFERRED TIMES FOR
SEVERE BOTH DAYS.
ON TEMPS...GENERALLY A CONSENSUS APPROACH LOOKED OK...EXCEPT IT
APPEARED TO BE A FEW DEGREES COOL IN MOST PERIODS BASED ON LOW
LEVEL THICKNESSES. MINOR TWEAKS UPWARD WERE REQUIRED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 230 PM EDT SUN APR 29 2012
ECMWF AND GFS HINT AT A LINGERING FRONTAL BOUNDARY AND NUMEROUS
WEAK SHORT WAVES PUSHING THROUGH THE OHIO VALLEY THROUGH THE FIRST
PART OF THE WEEKEND. CONFIDENCE IN THESE FEATURES IS
LOW...ALTHOUGH GIVEN THE PATTERN...LOW CHANCE POPS WILL BE NEEDED
THROUGH MUCH OF THE WORK WEEK. ALL BLEND HANDLES THIS RATHER WELL.
BY NEXT SUNDAY...THE ECMWF IS SIGNALING A CHANGE AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES...PUSH THE FRONTAL BOUNDARY SOUTH.
FOR NOW THIS WILL BE THE MAIN PERIOD WHERE WE WILL BE ABLE TO
REMOVE THE POPS.
THE SOUTHERLY FLOW EXPECTED THROUGH THE PERIOD ALONG WITH SHOULD
PROVIDE ABOVE NORMAL TEMPERATURES THROUGH MUCH OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 300000Z TAFS/...
ISSUED AT 632 PM EDT SUN APR 29 2012
TAIL END OF UPPER DISTURBANCE PASSING OVER NORTHERN ILLINOIS IS
EXPECTED TO BE IN THE PROCESS OF MOVING ACROSS THE LOCAL AREA BY THE
BEGINNING OF THE FORECAST PERIOD. NOTHING REALLY DEVELOPING ON THIS
TAIL...BUT THERE IS SOME ELEVATED INSTABILITY AROUND. AS A
RESULT...THERE IS A LOW POTENTIAL FOR CONVECTION IN THE VICINITY OF
THE TAF SITES THROUGH ABOUT 300200Z...BUT NOT ENOUGH TO PUT IN THE
FORECAST AT THIS TIME.
MODEL DATA SUGGEST THERE MAY BE ANOTHER DISTURBANCE MOVING INTO THE
AREA OUT OF THE SOUTHERN PLAINS AFTER 300800Z...BUT AGAIN COVERAGE
OF CONVECTION TOO QUESTIONABLE TO PUT IN THE FORECAST AT THIS TIME.
CEILINGS GENERALLY ABOVE 050 EXPECTED TO LOWER INTO THE 030-050
RANGE AFTER 300600Z WITH THE APPROACH OF WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
425 PM EDT SUN APR 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 352 PM EDT SUN APR 29 2012
A BROAD QUASI ZONAL TO SOUTHWEST FLOW WILL MAINTAIN ITSELF OVER
MOST OF THE NEXT WEEK...WITH SEVERAL FRONTAL WAVES AND THUS
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS PRESENTING THEMSELVES
ACROSS CENTRAL INDIANA. THIS SOUTHWEST FLOW WILL ALSO ALLOW
TEMPERATURES TO BE SEASONABLY WARM FOR MUCH OF THE NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCI FOR TONIGHT ARE POPS AND THUNDER CHANCES. MODELS ARE IN
GENERAL AGREEMENT ON LARGE SCALE FEATURES...BUT LEANED TOWARD NAM
AS OTHER MODELS APPEAR TO BE TOO WET BASED ON CURRENT TRENDS.
WARM FRONT SHOULD GRADUALLY PUSH NORTHWARD TONIGHT...AS A WEAK
SURFACE LOW MOVES OUT OF THE CENTRAL PLAINS. MOST GUIDANCE
APPEARED A BIT TOO AGGRESSIVE ON PRECIP WHEN MUCH OF THE
CONVECTION TO OUR WEST HAS STRUGGLED TO MAKE IT EASTWARD TODAY.
RAPID REFRESH AND RUC DEPICT BEST CHANCES OF PRECIP TONIGHT ACROSS
OUR NORTHWEST...AND CONSENSUS APPROACH TEMPERED SLIGHTLY DEPICTS
THIS WELL. INSTABILITY IS THERE BUT MINIMAL...AND BASED ON SREF
THUNDER PROBS HAVE GONE WITH ISOLATED THUNDER MENTION RATHER THAN
STRAIGHT THUNDERSTORM FORECAST. DID GO WITH CHANCE THUNDER IN THE
NORTHWEST LATE WHERE PROBABILTIES ARE A BIT HIGHER.
CONSENSUS APPROACH ON TEMPS AGREES WELL WITH UPSTREAM MINS FROM
LAST NIGHT...AND WILL STICK CLOSE TO THIS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCUS REMAINS PRECIP CHANCES THROUGHOUT...WITH BOUNDARY REMAINING
IN THE AREA IN ONE FORM OR ANOTHER AND ONE OR MORE VERY SUBTLE
WAVES PERHAPS AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. POPS
APPEARED A BIT HIGH IN PLACES...BUT NOT BY MUCH...GIVEN THE LACK
OF SIGNIFICANT UPPER LEVEL SUPPORT THROUGH THE FIRST PART OF THE
WEEK. HOWEVER...EXPECT THAT MESOSCALE INFLUENCES WILL HELP MAKE UP
FOR THIS. LEANED HEAVILY ON SREF THUNDER PROBS AND BOUNDARY
POSITION FOR DELINEATING BETWEEN WHERE TO FORECAST STRAIGHT
THUNDERSTORMS AND WHERE TO GO MORE SHOWERS WITH ISOLATED THUNDER
MENTION.
SLIGHT RISK FOR TOMORROW AND SEE TEXT FOR TUESDAY APPEAR
REASONABLE BASED ON MODEL CAPE/SHEAR PROFILES. IN SOMEWHAT TYPICAL
FASHION...AFTERNOON AND EARLY EVENING WOULD BE PREFERRED TIMES FOR
SEVERE BOTH DAYS.
ON TEMPS...GENERALLY A CONSENSUS APPROACH LOOKED OK...EXCEPT IT
APPEARED TO BE A FEW DEGREES COOL IN MOST PERIODS BASED ON LOW
LEVEL THICKNESSES. MINOR TWEAKS UPWARD WERE REQUIRED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 230 PM EDT SUN APR 29 2012
ECMWF AND GFS HINT AT A LINGERING FRONTAL BOUNDARY AND NUMEROUS
WEAK SHORT WAVES PUSHING THROUGH THE OHIO VALLEY THROUGH THE FIRST
PART OF THE WEEKEND. CONFIDENCE IN THESE FEATURES IS
LOW...ALTHOUGH GIVEN THE PATTERN...LOW CHANCE POPS WILL BE NEEDED
THROUGH MUCH OF THE WORK WEEK. ALL BLEND HANDLES THIS RATHER WELL.
BY NEXT SUNDAY...THE ECMWF IS SIGNALING A CHANGE AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES...PUSH THE FRONTAL BOUNDARY SOUTH.
FOR NOW THIS WILL BE THE MAIN PERIOD WHERE WE WILL BE ABLE TO
REMOVE THE POPS.
THE SOUTHERLY FLOW EXPECTED THROUGH THE PERIOD ALONG WITH SHOULD
PROVIDE ABOVE NORMAL TEMPERATURES THROUGH MUCH OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 292100Z KIND TAF UPDATE/...
ISSUED AT 425 PM EDT SUN APR 29 2012
APPEARS MOST OF THE VFR CEILINGS AROUND 040 HAVE DISSIPATED...SO
WILL RAISE THE FORECAST CEILING TO ABOVE 050 FOR THE REST OF THE
AFTERNOON/EARLY EVENING.
SHORT TERM MODEL DATA SUGGEST THE SOUTHEAST FRINGES OF UPPER
DISTURBANCE CURRENTLY PASSING ACROSS ILLINOIS WILL BEGIN MOVING INTO
THE KIND VICINITY AFTER ABOUT 292300Z. LITTLE SURFACE INSTABILITY
EXISTS...BUT THERE IS SOME ELEVATED INSTABILITY. SO FAR...NOT SEEING
ANY INDICATIONS OF DEVELOPMENT...SO WILL CONTINUE TO LEAVE OUT OF
THE FORECAST AT THIS TIME. PREVIOUS DISCUSSION FOLLOWS.
VFR CONDITIONS ARE EXPECTED TO DETERIORATE LATE IN THE FORECAST
PERIOD TO MVFR.
WAVE SHORT WAVE EXITING THE AREA CONTINUES TO INDICATE DIMINISHING
RADAR RETURNS EARLY THIS AFTERNOON. EXPECT THIS TREND TO
CONTINUE...BUT WILL CARRY SOME VCSH AT IND AND LAF FOR THE FIRST
FEW HOURS. DYING SYSTEM OVER WESTERN ILLINOIS IS EXPECTED TO
PROPAGATE NORTHEAST...BUT ONCE AGAIN DIMINISH NORTH OF THE COLD
FRONT. THUS VFR WILL CONTINUE.
SEVERAL QUICK MOVING SHORT WAVE ARE EXPECTED TO PUSH ACROSS
INDIANA THROUGH THE TAF PERIOD AS A WARM FRONT IS EXPECTED TO PUSH
NORTH ACROSS THE TAF SITES STARTING DURING THE OVERNIGHT HOURS AND
CONTINUING AFTER 12Z MONDAY. CONFIDENCE FOR PRECISE TIMING OF
SPECIFIC PRECIPITATION EVENTS IS LOW...THUS FOR NOW HAVE PAINTED
LARGE WINDOWS OF VCSH DURING THE FRONTAL PASSAGE LATE TONIGHT AND
ON MONDAY MORNING. THUNDERSTORMS WILL BE POSSIBLE WITH THE PASSAGE
OF THIS SYSTEM...BUT WILL LEAVE OUT OF THE TAFS FOR NOW AS PRECISE
TIMING AT SPECIFIC POINTS IS NOT CLEAR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JP/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
352 PM EDT SUN APR 29 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN
UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 352 PM EDT SUN APR 29 2012
A BROAD QUASI ZONAL TO SOUTHWEST FLOW WILL MAINTAIN ITSELF OVER
MOST OF THE NEXT WEEK...WITH SEVERAL FRONTAL WAVES AND THUS
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS PRESENTING THEMSELVES
ACROSS CENTRAL INDIANA. THIS SOUTHWEST FLOW WILL ALSO ALLOW
TEMPERATURES TO BE SEASONABLY WARM FOR MUCH OF THE NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCI FOR TONIGHT ARE POPS AND THUNDER CHANCES. MODELS ARE IN
GENERAL AGREEMENT ON LARGE SCALE FEATURES...BUT LEANED TOWARD NAM
AS OTHER MODELS APPEAR TO BE TOO WET BASED ON CURRENT TRENDS.
WARM FRONT SHOULD GRADUALLY PUSH NORTHWARD TONIGHT...AS A WEAK
SURFACE LOW MOVES OUT OF THE CENTRAL PLAINS. MOST GUIDANCE
APPEARED A BIT TOO AGGRESSIVE ON PRECIP WHEN MUCH OF THE
CONVECTION TO OUR WEST HAS STRUGGLED TO MAKE IT EASTWARD TODAY.
RAPID REFRESH AND RUC DEPICT BEST CHANCES OF PRECIP TONIGHT ACROSS
OUR NORTHWEST...AND CONSENSUS APPROACH TEMPERED SLIGHTLY DEPICTS
THIS WELL. INSTABILITY IS THERE BUT MINIMAL...AND BASED ON SREF
THUNDER PROBS HAVE GONE WITH ISOLATED THUNDER MENTION RATHER THAN
STRAIGHT THUNDERSTORM FORECAST. DID GO WITH CHANCE THUNDER IN THE
NORTHWEST LATE WHERE PROBABILTIES ARE A BIT HIGHER.
CONSENSUS APPROACH ON TEMPS AGREES WELL WITH UPSTREAM MINS FROM
LAST NIGHT...AND WILL STICK CLOSE TO THIS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCUS REMAINS PRECIP CHANCES THROUGHOUT...WITH BOUNDARY REMAINING
IN THE AREA IN ONE FORM OR ANOTHER AND ONE OR MORE VERY SUBTLE
WAVES PERHAPS AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. POPS
APPEARED A BIT HIGH IN PLACES...BUT NOT BY MUCH...GIVEN THE LACK
OF SIGNIFICANT UPPER LEVEL SUPPORT THROUGH THE FIRST PART OF THE
WEEK. HOWEVER...EXPECT THAT MESOSCALE INFLUENCES WILL HELP MAKE UP
FOR THIS. LEANED HEAVILY ON SREF THUNDER PROBS AND BOUNDARY
POSITION FOR DELINEATING BETWEEN WHERE TO FORECAST STRAIGHT
THUNDERSTORMS AND WHERE TO GO MORE SHOWERS WITH ISOLATED THUNDER
MENTION.
SLIGHT RISK FOR TOMORROW AND SEE TEXT FOR TUESDAY APPEAR
REASONABLE BASED ON MODEL CAPE/SHEAR PROFILES. IN SOMEWHAT TYPICAL
FASHION...AFTERNOON AND EARLY EVENING WOULD BE PREFERRED TIMES FOR
SEVERE BOTH DAYS.
ON TEMPS...GENERALLY A CONSENSUS APPROACH LOOKED OK...EXCEPT IT
APPEARED TO BE A FEW DEGREES COOL IN MOST PERIODS BASED ON LOW
LEVEL THICKNESSES. MINOR TWEAKS UPWARD WERE REQUIRED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 230 PM EDT SUN APR 29 2012
ECMWF AND GFS HINT AT A LINGERING FRONTAL BOUNDARY AND NUMEROUS
WEAK SHORT WAVES PUSHING THROUGH THE OHIO VALLEY THROUGH THE FIRST
PART OF THE WEEKEND. CONFIDENCE IN THESE FEATURES IS
LOW...ALTHOUGH GIVEN THE PATTERN...LOW CHANCE POPS WILL BE NEEDED
THROUGH MUCH OF THE WORK WEEK. ALL BLEND HANDLES THIS RATHER WELL.
BY NEXT SUNDAY...THE ECMWF IS SIGNALING A CHANGE AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES...PUSH THE FRONTAL BOUNDARY SOUTH.
FOR NOW THIS WILL BE THE MAIN PERIOD WHERE WE WILL BE ABLE TO
REMOVE THE POPS.
THE SOUTHERLY FLOW EXPECTED THROUGH THE PERIOD ALONG WITH SHOULD
PROVIDE ABOVE NORMAL TEMPERATURES THROUGH MUCH OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 291800Z TAFS/...
ISSUED AT 1255 PM EDT SUN APR 29 2012
VFR CONDITIONS ARE EXPECTED TO DETERIORATE LATE IN THE FORECAST
PERIOD TO MVFR.
WAVE SHORT WAVE EXITING THE AREA CONTINUES TO INDICATE DIMINISHING
RADAR RETURNS EARLY THIS AFTERNOON. EXPECT THIS TREND TO
CONTINUE...BUT WILL CARRY SOME VCSH AT IND AND LAF FOR THE FIRST
FEW HOURS. DYING SYSTEM OVER WESTERN ILLINOIS IS EXPECTED TO
PROPAGATE NORTHEAST...BUT ONCE AGAIN DIMINISH NORTH OF THE COLD
FRONT. THUS VFR WILL CONTINUE.
SEVERAL QUICK MOVING SHORT WAVE ARE EXPECTED TO PUSH ACROSS
INDIANA THROUGH THE TAF PERIOD AS A WARM FRONT IS EXPECTED TO PUSH
NORTH ACROSS THE TAF SITES STARTING DURING THE OVERNIGHT HOURS AND
CONTINUING AFTER 12Z MONDAY. CONFIDENCE FOR PRECISE TIMING OF
SPECIFIC PRECIPITATION EVENTS IS LOW...THUS FOR NOW HAVE PAINTED
LARGE WINDOWS OF VCSH DURING THE FRONTAL PASSAGE LATE TONIGHT AND
ON MONDAY MORNING. THUNDERSTORMS WILL BE POSSIBLE WITH THE PASSAGE
OF THIS SYSTEM...BUT WILL LEAVE OUT OF THE TAFS FOR NOW AS PRECISE
TIMING AT SPECIFIC POINTS IS NOT CLEAR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS DES MOINES IA
335 PM CDT SUN APR 29 2012
.SHORT TERM /TONIGHT/...
FORECAST CONCERNS CENTER AROUND CHANCE FOR LINGERING PRECIPITATION
TONIGHT. LARGE AREA OF PRECIP CONTINUES TO PUSH NORTH THROUGH THE
CWA...AND LINES UP WELL WITH ISENTROPIC LIFT AREA ON THE RUC 290K
SURFACE. HAVE TRENDED POPS TO CORRELATE WITH THIS AREA OF LIFT
TRANSLATING NORTH TO NORTHEASTWARD WITH TIME OVER THE NEXT 3 TO 6
HOURS. DEEPER SATURATION ENDS BY MID EVENING...WITH SOME DRIER AIR
MOVING IN ALOFT...WITH LOWEST LAYERS REMAINING SATURATED. SOME WEAK
ISENTROPIC LIFT STILL AROUND IN AREAS WITH THE MORE SHALLOW
SATURATION...THEREFORE HAVE ALSO MENTIONED SOME PATCHY DRIZZLE FOR
THE EVENING HOURS. ANY ELEVATED INSTABILITY CONFINED TO THE SOUTHERN
PORTION OF THE CWA...BUT HAS NOT MATERIALIZED MUCH EVEN THIS
AFTERNOON...SO ONLY HAVE SOME ISOLATED THUNDER MENTION ACROSS FAR
SOUTH FOR THIS EVENING. WITH THE SHALLOW LOW LEVEL
SATURATION...EXPECT STRATUS TO CONTINUE THROUGH THE NIGHT. WITH
WINDS EXPECTED TO BECOME LIGHT AND VARIABLE AS WEAK HIGH PRESSURE
BUILDS INTO THE STATE...SHALLOW MOISTURE AND RESIDUAL SURFACE
MOISTURE FROM THE RAINFALL COULD ALSO HAVE AREAS OF FOG POSSIBLY
DENSE FORM ACROSS THE CWA BY LATE EVENING INTO THE OVERNIGHT HOURS.
FOR NOW JUST MENTIONED THE FOG IN THE GRIDS...BUT WILL HAVE TO
MONITOR ITS DEVELOPMENT TO DETERMINE IF IT WILL BECOME DENSE.
OVERALL EXPECT PRECIP TO CLEAR FASTER THAN IN PREVIOUS
FORECASTS...SO HAVE ENDED ANY PRECIPITATION BY LATE EVENING AND HAVE
GONE DRY IN THE LATE NIGHT HOURS.
.LONG TERM /MONDAY THROUGH SUNDAY/...
WITH SYSTEM MOVING A BIT FASTER...MON SHOULD BE A DRY DAY AND LIKELY
THE ONLY FULLY DRY PERIOD OF THE FORECAST. BROAD SOUTHWEST FLOW
WILL PERSIST OVER THE CENTRAL U.S. FOR THE NEXT WEEK WITH A SERIES
OF UPPER LEVEL SYSTEM S LIFTING NEWD OUT OF THE SOUTHWEST U.S.
TIMING WILL BE TRICKY...BUT IT DOES APPEAR THERE WILL BE SOME RAIN
DURING EACH OF THE 12 HOUR PERIODS OF THE FORECAST...THOUGH NOT ALL
OF IT. THERE WILL BE INTERMITTENT CHANCES FOR SEVERE WEATHER WITH
THE BEST CHANCES LOOKING LIKE TUE NIGHT AND FRIDAY NIGHT RIGHT NOW.
SOME CAPPING IS BEGINNING TO TAKE PLACE WHICH WILL CUT DOWN THE
SEVERE POTENTIAL SOME. ALL IN ALL IT DOES LOOK LIKE A DECENT AMOUNT
OF RAIN DURING THE NEXT WEEK. NOT SURE THE HEAVIEST WILL BE IN THE
DRIEST AREAS HOWEVER. THE THE DRY NWRN ZONES WILL GET ABOVE NORMAL
RAINFALL THIS WEEK. TEMPS WILL WARM ABOVE NORMAL ON MONDAY AND
REMAIN THAT WAY THROUGH THE WEEK.
&&
.AVIATION...29/18Z
LOW STRATUS EXPECTED TO REMAIN ACROSS THE CWA TODAY...AND BUILD INTO
KALO AND KMCW THROUGH THE AFTERNOON AS AREA OF SHOWERS WITH A FEW
ISOLATED THUNDERSTORMS CONTINUES TO SPREAD NORTHWARD ACROSS THE CWA.
RAIN AREA TO MOVE NORTH NORTHEASTWARD THROUGH THE AFTERNOON...AND
TAPER OFF FROM SOUTHWEST TO NORTHEAST THIS EVENING. WINDS DIMINISH
AND WILL BE VARIABLE LATE TONIGHT WITH AN AREA OF SFC HIGH PRESSURE
BUILDING INTO THE CWA. WITH THE RAIN TODAY...EXPECT AREA OF LOW
STRATUS TO CONTINUE THROUGH THE NIGHT...POSSIBLY LOWERING INTO
LIFR/IFR CIGS. ALSO EXPECT FOG WITH HIGH RESIDUAL SFC MOISTURE...SO
HAVE DROPPED VSBYS INTO THE LIFR/IFR CATEGORY AT ALL TAF SITES BY
LATE EVENING INTO THE OVERNIGHT HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MJB
LONG TERM...MS APR 12
AVIATION...MJB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
154 PM EDT SUN APR 29 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY WEATHER TODAY AND TONIGHT. A WARM
FRONT WILL APPROACH THE AREA FROM THE SOUTHWEST ON MONDAY, BRINGING
THE CHANCE OF THUNDERSTORMS. THE WARM FRONT WILL LIFT NORTH OF THE
AREA FOR THE MID-WEEK, WITH ABOVE NORMAL TEMPERATURES EXPECTED FOR
THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED WITH NO
CHANGES TO THE GOING FORECAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB RIDGE AXIS
CENTERED ACROSS THE WESTERN GREAT LAKES WITH THE UPPER OHIO VALLEY
IN A NORTHWESTERLY FLOW AHEAD OF THIS FEATURE. AT THE SURFACE, HIGH
PRESSURE EXTENDS FROM ONTARIO SOUTHEASTWARD ACROSS PENNSYLVANIA AND
INTO THE MID-ATLANTIC. THE 12Z KPIT SOUNDING INDICATED A DEEP
LAYER OF DRY AIR WITH SUBSIDENCE ALOFT. SAT IMAGERY CONFIRMS THIS
WITH CLEAR SKIES ASIDE FROM SOME PASSING CIRRUS.
THE MID-LEVEL RIDGE WILL MOVE INTO THE OHIO VALLEY THIS AFTERNOON
AND ACROSS THE AREA TONIGHT, ALLOWING FOR DRY WEATHER. HIGH
PRESSURE WILL SHIFT FROM ONTARIO INTO NY/EASTERN PA THROUGH THIS
PERIOD, ALLOWING LIGHT NORTHERLY WINDS TODAY TO SHIFT TO MORE
SOUTHEASTERLY BY DAWN ON MONDAY. SKIES WILL BE MOSTLY CLEAR TODAY,
WITH CLOUD COVERAGE BEGINNING TO INCREASE FROM THE SOUTH OVERNIGHT
AS MOISTURE SPILLS ACROSS A FRONTAL BOUNDARY TO THE SOUTH. TEMPS
TODAY ARE CLOSEST TO THE HRRR, WARMING TO NEAR NORMAL SEASONAL
VALUES. LOWS TONIGHT ARE CLOSER TO THE WARMER MET GUIDANCE.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
GFS/NAM/ECMWF ARE IN AGREEMENT THAT WARM FRONT WILL RETURN TO
REGION DURING THE DAY MONDAY AS SHORTWAVE RIDES MOVES ACROSS THE
GREAT LAKES. THIS WILL BRING AN INCREASING CHANCE FOR SHOWERS AND
STORMS DURING THE DAY. SURFACE LOW WILL MOVE TO LAKE ERIE MONDAY
NIGHT WITH COLD FRONT ENTERING THE REGION.
THE SURFACE LOW WILL PASS NORTH OF THE AREA MONDAY NIGHT, WITH
LIKELY POPS FORECAST ACROSS THE AREA. WITH THE WARM FRONT LIFTING
NORTH OF THE AREA, THE UPPER OHIO VALLEY WILL BE IN THE WARM
SECTOR TUESDAY AND WEDNESDAY. CHANCE POPS ARE FORECAST EACH DAY
WITH CONVECTION. UPPER LEVEL HEIGHTS WILL BE ON THE RISE THROUGH THE
PERIOD AS RIDGE DEVELOPS OFF THE CAROLINAS WITH ABOVE NORMAL
TEMPERATURES BY MID WEEK.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LONG TERM FORECAST WAS BASED ON GFS/ECMWF ENSEMBLE MEANS AND
FEATURES THE FLATTENING OF BROAD ERN CONUS RIDGE AS THE WEEKEND
APPRCHES. ADJUSTMENTS WERE INCLUDED TO PCPN PROBABILITIES ON
THURSDAY AND FRIDAY TO ACCOUNT FOR EXPECTED FRONTAL POSITIONING.
SFC CDFNT IS STILL PROJECTED FOR A FRIDAY PASSAGE UNDER THIS
PATTERN...AND POPS WERE THUS REDUCED FOR THE WEEKEND.
WARM MIDWEEK TEMPERATURES SHOULD CONTINUE INTO THURSDAY WITH WARM
ADVECTION CONTINUING IN ADVANCE OF THE APPRCHG CDFNT. GIVEN THE
PROJECTED AMPLITUDE OF THE MID/UPR RIDGE...HAVE STAYED WITH THE
COOLER HPC GUIDANCE IN THAT TIME FRAME WHICH PROJECTS HIGHS
APPROXIMATELY 10 DEGREES ABOVE THE SEASONAL NORMALS.
THE AFOREMENTIONED RIDGE EROSION PROGNOSIS FOR THE WEEKEND IS NOT AS
DRAMATIC AS PREVIOUS SOLUTIONS...WITH EXCEPTION OF LATEST ECMWF
FORECAST WHICH HAS BEEN DISCOUNTED. TEMPERATURES WERE THUS FORECAST
CLOSER TO...BUT STILL A FEW DEGREES ABOVE THE NORMALS TO ACCOMPANY
THE REDUCED POPS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SURFACE HIGH PRES WL SLIDE ACRS THE GREAT LAKES AND CONTINUE TO PUSH
DRIER AIR OVR THE UPR OH VALLEY REGION TDA. ALTHOUGH HIGH...AND MID
LVL CLDS WL BE ON THE INCRS THROUGH TNGT...VFR CONDITIONS CAN BE
EXPECTED WITH LGT NORTH WIND VEERING TO THE EAST THROUGH THE TAF PD.
BY MONDAY MRNG...SHRA/TSRA ARE ANTICIPATED WITH WARM...MOIST SURGE
OVR THE UPR OH REGION. MVFR RESTRICTION SHOULD BE EXPECTED IN THIS
CONVECTIVE ACTIVITY...WHICH MAY CONTINUE INTO THE AFTN DEPENDING ON
TIMING OF SHRTWV SUPPORT.
.OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...
RESTRICTIONS IN SCT SHRA AND TSRA ARE POSSIBLE MONDAY NGT THROUGH
WEDNESDAY AS GREAT LAKES LOW PRES ADVECTS WARMTH AND MOISTURE ACROSS
THE REGION. MORE TSRA ARE ANTICIPATED FOR THURSDAY IN ASSOCIATION
WITH THE SYSTEMS CDFNT APPRCH.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
306 PM EDT SUN APR 29 2012
.SYNOPSIS...
ISSUED AT 305 PM EDT SUN APR 29 2012
HIGH PRESSURE WILL MOVE EAST AND A WARM FRONT WILL PUSH NORTH
TOWARDS SOUTHERN LOWER MICHIGAN TONIGHT. SOME SHOWERS AND
THUNDERSTORMS WILL BE ARRIVING AFTER MIDNIGHT TONIGHT THEN SPREAD
NORTH ON MONDAY. WARMER TEMPERATURES ALONG WITH SCATTERED SHOWERS
AND THUNDERSTORMS CAN BE EXPECTED FROM TUESDAY THROUGH THURSDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 305 PM EDT SUN APR 29 2012
AREA OF ISENTROPIC ASCENT NORTH OF SFC WARM FRONT IS GENERATING
RAIN ACROSS ILLINOIS THIS AFTERNOON. THIS WILL CONTINUE NORTHEAST
AND EDGE INTO FAR SOUTHWEST LOWER MICHIGAN THIS EVENING. LEADING EDGE
WILL HAVE TO OVERCOME DRY AIR INITIALLY BUT 12Z MODEL RH PROFILES
AND HRRR RUC INDICATE THE DRY AIR WILL BE OVERCOME AS LOW LEVEL
FLOW GOES SOUTHEAST WITH THE SFC RIDGE MOVING EASTWARD.
WILL BRING CHANCE POPS IN THIS EVENING AND THEN EXPAND NORTHWARD
AFTER MIDNIGHT. WILL HAVE THUNDERSTORMS ACROSS THE SOUTHERN
FORECAST AREA AS POTENTIAL FOR ELEVATED CONVECTION EXISTS WITH
TOTAL TOTALS IN THE UPPER 40S. MAIN SLUG OF QPF MOVES EAST DURING
THE DAY ALONG WITH DEEP MOISTURE...WHICH MEANS LIKELY POPS IN THE
MORNING FOLLOWED BY CHANCE POPS IN THE AFTERNOON.
MAX TEMPS WILL BE TRICKY ON MONDAY AS MODEL RH PROFILES SUGGEST
LOWER CLOUDS WILL STICK AROUND ALL DAY...AND UPSTREAM OBS IN THE
CLOUDS NORTH OF THE WARM FRONT THIS AFTERNOON ARE CURRENTLY STUCK
IN THE 40S. WENT A BIT BELOW GUIDANCE FOR MONDAY MAXES.
MONDAY NIGHT WILL SEE LOW CLOUDS DECREASE AS WEAK SFC RIDGING
BUILDS IN. WILL GO WITH A DRY FORECAST AS DEEP MOISTURE HAS
DEPARTED BY EVENING. GUIDANCE TEMPS HAVE TRENDED DOWNWARD AND SO
TWEAKED MINS LOWER.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 305 PM EDT SUN APR 29 2012
THE MAIN LONG TERM FCST CHALLENGE CONTINUES TO INVOLVE DETERMINING
PROBABILITIES FOR RAIN AND CONVECTION THROUGH MOST OF THE LONG RANGE
FCST PERIOD.
A WEAK HIGH PRESSURE RIDGE WILL PRODUCE DRY WX THROUGH AT LEAST
MIDDAY TUESDAY. WE WILL MAINTAIN MENTION OF A CHC OF SHOWERS/STORMS
OVER OUR SOUTHERN FCST AREA TUESDAY AFTERNOON AS THE WARM FRONT
LIFTS NORTH. IT WILL BE MILDER TUESDAY WITH MAX TEMPS REACHING THE
LOW TO MID 70S. SHOWERS AND A FEW TSTORMS ARE ANTICIPATED TUESDAY
NIGHT AS THE WARM FRONT CONTINUES TO LIFT NORTHWARD.
THE MODERATING TREND WILL CONTINUE WEDNESDAY WITH OUR FCST AREA
SOLIDLY IN THE WARM SECTOR WITH MAX TEMPS REACHING THE UPPER 70S TO
LOWER 80S. WE WILL MAINTAIN CHC POPS FOR SHOWERS/TSTORMS WEDNESDAY
AS MODERATE INSTABILITY DEVELOPS IN THE WARM SECTOR. HOWEVER I AM
NOT CONVINCED THAT THERE WILL BE A GOOD TRIGGERING MECHANISM/FOCUS
FOR CONVECTIVE INITIATION TO OCCUR. MOST OF THE DAY WILL LIKELY BE
DRY. 12Z GFS GUIDANCE SUGGESTS THE BETTER CONVECTIVE POTENTIAL
WEDNESDAY AFTERNOON WILL BE MUCH FURTHER NORTH NEAR THE WARM FRONT
AND ALSO WELL TO OUR NW IN CLOSER PROXIMITY TO THE SFC LOW OVER THE
UPPER MIDWEST.
THE WEDNESDAY NIGHT TIME FRAME REMAINS FAVORED FOR CONVECTIVE
DEVELOPMENT DUE LARGELY TO FORCING FROM A 35 TO 45 KT LLJ. 1000-850
MB MOISTURE TRANSPORT ALSO LOOKS FAVORABLE BY WEDNESDAY EVENING.
SHOWERS AND TSTORMS WILL LIKELY LINGER/REDEVELOP ON THURSDAY WITH
SHOWERS LINGERING FRIDAY BEFORE A COOLER AND DRIER AIRMASS ADVECTS
FOR THE WEEKEND WITH TEMPS RETURNING TO NEAR NORMAL BY THEN.
CANNOT RULE OUT A FEW STRONG TO SEVERE STORMS LATE WEDNESDAY THROUGH
THURSDAY AS INSTABILITY INCREASES ALONG WITH BRIEFLY STRONGER
FORCING FROM THE LLJ. HOWEVER WE CONCUR WITH THE PREVIOUS SHIFT THAT
THE OVERALL SEVERE WX THREAT MIDWEEK LOOKS FAIRLY LOW DUE TO SEVERAL
LIMITING FACTORS INCLUDING WEAK DEEP LAYER SHEAR STAYING GENERALLY
UNDER 30 KTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 122 PM EDT SUN APR 29 2012
ASIDE FROM A STEADY BREEZE AT ABOUT 10 KTS THIS AFTERNOON AND
EVENING...NO SIGNIFICANT IMPACTS TO MENTION IN THE TAFS THROUGH
00Z. ATTENTION IS FOCUSED ON ARRIVAL OF SHOWERS OVERNIGHT AND
POTENTIAL IFR CONDITIONS AFTER 12Z MONDAY. AFTER LOOKING AT
OBSERVATIONS UPSTREAM IN NORTHERN MISSOURI AND SOUTHERN ILLINOIS
WHERE THE CURRENT BATCH OF RAINFALL IS...CIGS AND VISBYS ARE
INDICATIVE OF FAIRLY WIDESPREAD IFR CONDITIONS. I DO NOT EXPECT
THOSE CONDITIONS TO ARRIVE PRIOR TO 12Z...AND MAY HOLD OFF UNTIL
THE TAIL END OF THIS TAF PERIOD.
NAM MODEL RH FOR <1000 FT REVEALS SATURATED CONDITIONS OCCURRING
CLOSER TO NOON OR 1PM. THUS I INDICATED A BIT OF A BUFFER BY GOING
WITH 1500 FT CIGS BY 16Z AND LIKELY GOING TO IFR BY 18Z. COULD BE
SOME THUNDERSTORMS AROUND DURING THE MORNING BUT WATER
VAPOR/LIGHTNING ANALYSIS INDICATES THE TREND IS LESS FAVORABLE FOR
TSTORM DEVELOPMENT AS THIS SYSTEM MOVES TOWARD SW LOWER MICHIGAN.
&&
.MARINE...
ISSUED AT 305 PM EDT SUN APR 29 2012
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
TUESDAY. THUNDERSTORMS ARE POSSIBLE SOUTH OF MUSKEGON ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 305 PM EDT SUN APR 29 2012
HEAVY RAIN IS POSSIBLE WEDNESDAY AND THURSDAY WHICH COULD LEAD TO
RISES ON THE RIVERS BY THE END OF THE WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...HOVING
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS HASTINGS NE
404 PM CDT SUN APR 29 2012
.SHORT TERM...THROUGH MONDAY AFTERNOON. UNFORTUNATELY...CONFIDENCE
IS BELOW AVERAGE DURING THE NEXT 24 HOURS REGARDING SEVERAL
ELEMENTS OF THE FORECAST...INCLUDING CLOUD/FOG TRENDS AND
THUNDERSTORMS/POSSIBLE SEVERE WEATHER CHANCES.
STARTING OFF WITH HERE AND NOW...19Z OBJECTIVE SURFACE ANALYSIS
INDICATES LIGHT EASTERLY BREEZES ACROSS MOST OF THE CWA...FLOWING
OUT OF A SURFACE HIGH CENTERED WELL TO THE NORTHEAST ACROSS THE
GREAT LAKES. THE CWA IS SITUATED WELL NORTH OF THE PRIMARY
REGIONAL SYNOPTIC EAST-WEST BOUNDARY/WARM FRONT...STRETCHED NEAR
THE OK/KS BORDER ACROSS SOUTHERN MO. ALOFT...WATER VAPOR IMAGERY
AND SHORT TERM MODEL DATA INDICATES A CLOSED 500MB LOW DRIFTING
NORTH OUT OF ND INTO CANADA...BUT WITH A TROUGH AXIS TRAILING
SOUTH-SOUTHWEST INTO THE NE/WY/CO BORDER AREA. AHEAD OF THIS
SYNOPTIC SCALE TROUGH AXIS...A LEAD SHORTWAVE IS IN THE PROCESS OF
EXITING THE CWA TO THE EAST...AND IS DRIVING ONGOING SHOWERS
ACROSS SOUTHEAST NEB. VISIBLE SATELLITE IMAGERY CONFIRMS WHY THE
TEMPERATURE FORECAST TODAY HAS BEEN FRUSTRATING...WITH AT LEAST
PARTIAL CLEARING DOMINATING SEVERAL COUNTIES WEST OF HIGHWAY
281...WHILE A SOLID LOW STRATUS DECK HAS STOOD FIRM ACROSS MUCH OF
THE CENTRAL/EAST...WITH A RENEWED NORTHWARD EXPANSION OF LOW
STRATUS NOW EVIDENT OUT OF NORTH CENTRAL KS. AS A RESULT...IT NOW
LOOKS LIKE MANY OF THESE CENTRAL/EASTERN COUNTIES MAY STRUGGLE TO
ATTAIN HIGHS IN THE MID-UPPER 50S...AT LEAST 5-10 DEGREES COOLER
THAN ORIGINALLY EXPECTED.
LATE THIS AFTERNOON THROUGH 00Z...WILL FOCUS THE MAIN CHANCES FOR
POSSIBLE SHOWER/STORM DEVELOPMENT WEST OF A LINE FROM
GREELEY-PLAINVILLE...WHERE CLEARING IS ALLOWING AT LEAST A FEW
HUNDRED J/KG OF 0-1KM MLCAPE TO BUILD. SHORT TERM REFLECTIVITY
PROGS FROM THE HRRR AND 12Z 4KM WRF-NMM SUPPORT THE POSSIBILITY OF
A FEW SHOWERS/STORMS DEVELOPING INTO THESE WESTERN ZONES BEFORE
DARK...AND ALTHOUGH NOT EXPECTING SEVERE WEATHER...A FEW INSTANCES
OF SMALL HAIL/GUSTY WINDS ARE NOT OUT OF THE QUESTION.
TURNING TO THE EVENING 00Z-06Z PERIOD...WILL KEEP LOW-END
THUNDERSTORM CHANCES GOING FOR MUCH OF NORTH CENTRAL KS...AND IN
NEB MAINLY WEST OF A GREELEY-ALMA LINE AS THE MAIN 500MB SHORTWAVE
AXIS SWINGS THROUGH THE CWA. AGAIN...SUPPOSE A FEW INSTANCES OF
SMALL HAIL NOT OUT OF THE QUESTION. FOR THE LATE NIGHT 06Z-12Z
PERIOD...KEPT LOW-END THUNDER CHANCES CONFINED TO A HANDFUL OF
FAR SOUTHWESTERN COUNTIES...IN CLOSEST PROXIMITY TO 850MB THETA-E
ADVECTION TIED TO A MODEST LOW LEVEL JET NOSING OUT OF WESTERN KS.
ALL THIS BEING SAID THOUGH...THE VAST MAJORITY OF THE CWA SHOULD
REMAIN DRY THROUGH THE NIGHT. TURNING TO OTHER OVERNIGHT
ISSUES...AFTER HAVING A ROUND OF LOCALLY DENSE FOG LAST
NIGHT...THERE ARE FAIRLY STRONG INDICATIONS IN NUMERICAL GUIDANCE
AND ALSO VISIBILITY PROBABILITY PROGS FROM THE SREF THAT ANOTHER
FAIRLY WIDESPREAD ROUND OF FOG SHOULD MATERIALIZE TONIGHT...THANKS
TO THE COMBINATION OF LIGHT WINDS AND A SATURATED BOUNDARY LAYER.
CONFIDENCE IN PLACEMENT WAS CERTAINLY NOT HIGH ENOUGH FOR A
HEADLINE YET...BUT WILL INSERT VISIBILITY BELOW 1 MILE INTO THE
GRIDS AND ALSO THE HWO. AS FOR LOW TEMPS...MAY END UP TOO COOL IF
A SOLID STRATUS BLANKET HOLDS FIRM...BUT WILL AIM FOR MID-UPPER
40S MOST AREAS.
TURNING TO MONDAY...OBVIOUSLY FOG COULD BE A CONCERN FOR THE FIRST
FEW HOURS AFTER SUNRISE. THEREAFTER...CONFIDENCE REMAINS UNUSUALLY
LOW IN THUNDERSTORM PROBABILITY/COVERAGE. THE GENERAL BIG PICTURE
INVOLVES A QUASI- ZONAL FLOW ALOFT...AS A LOW AMPLITUDE MID LEVEL
WAVE TRACKS FROM EASTERN CO INTO KS/SOUTHERN NEB. WITH WEAK
CAPPING EVIDENT IN FORECAST SOUNDINGS...AND CONTINUED 850MB
THETA-E ADVECTION...SEVERAL DETERMINISTIC MODELS SUCH AS THE
NAM/ECMWF/GFS ALL BRING STORMS INTO MUCH OF THE SOUTHWEST CWA
ALREADY IN THE MORNING...WHILE ON THE OTHER HAND...THE 4KM WRF-NMM
KEEPS THE MORNING CONVECTION-FREE. THEN DURING THE AFTERNOON...AN
EVEN STRONGER CONVECTIVE SIGNAL DEVELOPS IN SEVERAL DETERMINISTIC
MODELS...WHILE AGAIN THE 4KM REMAINS STRANGELY DRY. ALTHOUGH THE
ULTIMATE EXTENT OF DESTABILIZATION WILL BE STRONGLY INFLUENCED BY
HOW QUICKLY MORNING FOG/STRATUS VACATES...THE 18Z NAM ADVERTISES A
RESPECTABLE SEVERE WEATHER SETUP FOR THE MID-LATE AFTERNOON ACROSS
PARTS OF THE SOUTHERN CWA...BUT ESPECIALLY SOUTHERN ZONES WITH AT
LEAST 1500 J/KG 0-1KM MLCAPE...AND AROUND 40KT OF DEEP LAYER
SHEAR. ALTHOUGH THE OFFICIAL SPC DAY 2 SLIGHT RISK BARELY BRUSHES
THE FAR SOUTHERN CWA...WOULD NOT BE A BIT SURPRISED TO SEE THIS
EXTEND FARTHER NORTH ON THE UPCOMING DAY 1 PRODUCTS...AND WILL
INTRODUCE A SEVERE MENTION FOR HAIL/WIND IN THE HWO EXTENDING INTO
MONDAY EVENING. ALTHOUGH ONLY MODEST SHEAR IN THE LOWEST 1KM
SHOULD LIMIT A TORNADO THREAT...THIS POSSIBILITY IS ALSO NOT OUT
OF THE QUESTION NEAR THE NORTHWARD LIFTING INSTABILITY
GRADIENT/WARM FRONT IN KS ZONES. TEMPERATURE WISE MONDAY...STAYED
CLOSE TO GUIDANCE CONSENSUS...WHICH LOWERED MOST AREAS AT LEAST
2-3 DEGREES FROM PREVIOUS FORECAST INTO MAINLY THE 70-73 RANGE.
WOULD NOT BE SURPRISED THOUGH TO SEE WIDESPREAD CLOUDS ULTIMATELY
KEEP SOME AREAS IN THE 60S...JUST CAN/T SAY WHERE YET.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY. THIS IS VERY COMPLEX
WEATHER PATTERN WITH NUMEROUS WEAK SHORT WAVES CROSSING OUR FORECAST
AREA RESULTING IN ON AND OFF AGAIN SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS. TEMPERATURES WILL BE WARM FOR THIS TIME OF YEAR WITH
HIGHS IN THE 70S AND 80S THROUGHOUT THE PERIOD. NORMAL HIGHS ARE ONLY
IN THE MID TO UPPER 60S.
MONDAY NIGHT...SEVERAL OF THE THUNDERSTORMS THAT DEVELOP DURING THE
DAY ON MONDAY MAY PERSIST INTO THE EVENING/OVERNIGHT HOURS. A FEW OF
THESE THUNDERSTORMS MAY BE SEVERE...PRIMARILY SOUTH OF INTERSTATE 80.
TUESDAY...TEMPERATURES WARM WITH SOUTHERLY FLOW INTO THE 80S ACROSS
THE ENTIRE FORECAST AREA. THE ATMOSPHERE SHOULD BE PRETTY UNSTABLE BY
AFTERNOON AND A WEAK SHORT WAVE WILL BE MOVING ACROSS THE AREA. AM
ONLY GOING WITH A SLIGHT CHANCE OF THUNDERSTORMS DUE TO THE LIMITED
FORCING...BUT IF STORMS FORM THEY COULD CERTAINLY BE SEVERE GIVEN
APPRECIABLE DEEP LAYER SHEAR AND INSTABILITY.
WEDNESDAY INTO THURSDAY...A SFC FRONTAL BOUNDARY WILL STALL OUT
ACROSS OUR CWA AND MEANDER A BIT BACK AND FORTH ACROSS OUR CWA.
THERE WILL BE AT LEAST MODERATE INSTABILITY AND WITH WEAK UPPER
WAVES PASSING THROUGH WE COULD POP A FEW THUNDERSTORMS. WEAK DEEP
LAYER SHEAR MAY ACTUALLY BE ONE OF THE HINDERING FACTORS FOR SEVERE
WEATHER...BUT MODERATE INSTABILITY MAY BE ENOUGH TO ALLOW A FEW
STORM TO REACH SEVERE WEATHER THRESHOLDS SHOULD THEY FORM.
FRIDAY THROUGH SUNDAY. FRIDAY IS THE ONLY DRY DAY IN THE CURRENT
FORECAST AND EVEN THAT CAN NOT BE GUARANTEED. A STRONG UPPER LEVEL
TROUGH WILL BEGIN TO DEVELOP ACROSS THE WESTERN CONUS BY NEXT WEEKEND
AND WE COULD SEE A FEW CHANCES OF THUNDERSTORMS OUT AHEAD OF THIS
TROUGH...BUT BETTER CHANCES FOR THUNDERSTORMS MIGHT HOLD OFF UNTIL
JUST BEYOND THE END OF THIS FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1240 PM CDT SUN APR 29 2012/
AVIATION...18Z KGRI TAF. ALTHOUGH CONFIDENCE IN THE TIMING
DETAILS IS LOW...THERE IS INCREASING EVIDENCE THAT LIFR VISIBILITY
AND/OR CEILING WILL DEVELOP LATE TONIGHT INTO MONDAY
MORNING...SOMEWHAT SIMILAR TO WHAT HAPPENED THIS MORNING. STARTING
WITH THIS AFTERNOON...KGRI IS STARTING OUT WITH IFR CEILING/MVFR
VISIBILITY...BUT BASED ON TRENDS NOT FAR TO THE WEST...WILL
OPTIMISTICALLY CALL FOR A RETURN TO VFR CONDITIONS BY MID-LATE
AFTERNOON AS LOW CLOUDS SCATTER OUT. WILL KEEP VFR INTACT FOR MUCH
OF THE EVENING...BUT THEN AS WINDS BECOME LIGHT AND VARIABLE
OVERNIGHT AND BOUNDARY LAYER RELATIVE HUMIDITY REMAINS
HIGH...ANTICIPATE REDEVELOPMENT OF FOG AT SOME POINT. CERTAINLY
1/4SM VISIBILITY NOT OUT OF THE QUESTION...BUT WILL NOT OFFICIALLY
ADVERTISE QUITE THAT LOW YET. CONFIDENCE IS QUITE LOW ON WHAT
HAPPENS DURING THE LAST FEW HOURS OF THE PERIOD...BUT KEPT CEILING
NO BETTER THAN MVFR. AS FOR PRECIPITATION CHANCES...ALTHOUGH A
ROGUE SHOWER OR EVEN A THUNDERSTORM IS NOT COMPLETELY OUT OF THE
QUESTION LATER THIS AFTERNOON/EVENING AND AGAIN MONDAY
MORNING...THE LIKELIHOOD IS LOW ENOUGH TO NOT INSERT AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...PFANNKUCH
LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1240 PM CDT SUN APR 29 2012
.AVIATION...18Z KGRI TAF. ALTHOUGH CONFIDENCE IN THE TIMING
DETAILS IS LOW...THERE IS INCREASING EVIDENCE THAT LIFR VISIBILITY
AND/OR CEILING WILL DEVELOP LATE TONIGHT INTO MONDAY
MORNING...SOMEWHAT SIMILAR TO WHAT HAPPENED THIS MORNING. STARTING
WITH THIS AFTERNOON...KGRI IS STARTING OUT WITH IFR CEILING/MVFR
VISIBILITY...BUT BASED ON TRENDS NOT FAR TO THE WEST...WILL
OPTIMISTICALLY CALL FOR A RETURN TO VFR CONDITIONS BY MID-LATE
AFTERNOON AS LOW CLOUDS SCATTER OUT. WILL KEEP VFR INTACT FOR MUCH
OF THE EVENING...BUT THEN AS WINDS BECOME LIGHT AND VARIABLE
OVERNIGHT AND BOUNDARY LAYER RELATIVE HUMIDITY REMAINS
HIGH...ANTICIPATE REDEVELOPMENT OF FOG AT SOME POINT. CERTAINLY
1/4SM VISIBILITY NOT OUT OF THE QUESTION...BUT WILL NOT OFFICIALLY
ADVERTISE QUITE THAT LOW YET. CONFIDENCE IS QUITE LOW ON WHAT
HAPPENS DURING THE LAST FEW HOURS OF THE PERIOD...BUT KEPT CEILING
NO BETTER THAN MVFR. AS FOR PRECIPITATION CHANCES...ALTHOUGH A
ROGUE SHOWER OR EVEN A THUNDERSTORM IS NOT COMPLETELY OUT OF THE
QUESTION LATER THIS AFTERNOON/EVENING AND AGAIN MONDAY
MORNING...THE LIKELIHOOD IS LOW ENOUGH TO NOT INSERT AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 1155 AM CDT SUN APR 29 2012/
UPDATE...JUST COMPLETED AN UPDATE FOR THIS AFTERNOON...ALTHOUGH
ADMITTEDLY CONFIDENCE IS A BIT LOW IN THE DETAILS. IN
SHORT...SPLIT THE LOW-END RISKS FOR A FEW THUNDERSTORMS INTO TWO
AREAS...ONE MAINLY EAST OF A YORK-OSBORNE LINE ASSOCIATED WITH THE
WEAK CONVECTION EVIDENT ON RADAR NOW AFFECTING THE HEBRON AREA AND
TIED TO AN EXITING SHORTWAVE...AND THE OTHER AREA FOR LATER THIS
AFTERNOON GENERALLY WEST OF AN ORD-PLAINVILLE LINE...WHERE BOTH
THE NAM/RUC ADVERTISE AT LEAST SEVERAL HUNDRED J/KG OF SBCAPE
DEVELOPING AS MODEST FORCING INCREASES AHEAD OF THE NEXT BATCH OF
SHORTWAVE ENERGY MOVING IN FROM THE WEST. ALTHOUGH NOT
ANTICIPATING SEVERE STORMS IN THE WESTERN AREA...COULD EASILY
FORESEE A FEW STRONG STORMS WITH DIME-NICKEL HAIL AND 50 MPH WIND
POTENTIAL. ALTHOUGH THE MAJORITY OF THE CWA WILL LIKELY REMAIN
DRY THIS AFTERNOON...DECIDED TO AT LEAST THROW A TOKEN SLIGHT
CHANCE OF A SPRINKLE ALL AREAS. OTHERWISE...CLOUD AND RESULTANT
TEMP TRENDS FOR THIS AFTERNOON ARE ALSO QUITE TRICKY. GENERAL
EXPECTATION IS THAT AT LEAST PARTIAL CLEARING WILL CONTINUE
WORKING INTO THE CWA FROM WEST-EAST...BUT WITH EASTERN AREAS
POSSIBLY STRUGGLING TO BREAK OUT OF LOW STRATUS EVEN BY LATER THIS
AFTERNOON. CURRENT SATELLITE IMAGERY REVEALS A BIT SHARPER
CLEARING LINE THAN EARLIER EXPECTED ACROSS THE WESTERN 1/2 OF THE
CWA. AS A RESULT...LEFT AFTERNOON HIGHS IN WESTERN COUNTIES
ESSENTIALLY UNCHANGED FROM PREVIOUS FORECAST...WITH MID-UPPER 60S.
HOWEVER...LOWERED EASTERN NEB ZONES A SOLID 2-4 DEGREES WITH SOME
PLACES POSSIBLY STRUGGLING TO REACH LOW 60S. IN BETWEEN...THE TRI-
CITIES ARE A TOUGH CALL...BUT WILL AIM FOR A 62-65 RANGE. NO
NOTABLE CHANGES MADE BEYOND THIS AFTERNOON YET.
PREV DISCUSSION... /ISSUED 835 AM CDT SUN APR 29 2012/
UPDATE...JUST STARTING TO GET A HANDLE ON TRENDS FOR TODAY...BUT
FIRST ORDER OF BUSINESS WAS UPDATING TO EXTEND COVERAGE OF FOG
WELL INTO THE MORNING HOURS...INCLUDING A MENTION OF PATCHY DENSE
FOG ACROSS A GOOD PERCENTAGE OF MAINLY THE CENTRAL/EASTERN CWA
BASED ON AUTOMATED OBS AND NDOR WEB CAMS. GLANCING AT BOUNDARY
LAYER RH PROGS FROM VARIOUS MODELS...LOW STRATUS AND FOG COULD BE
FAIRLY SLOW TO BURN OFF TODAY...ESPECIALLY ACROSS PARTS OF THE
SOUTHEAST 1/3 OR SO OF THE CWA. OBVIOUSLY THE LONGER FOG AND/OR
LOW STRATUS LINGERS...THE HARDER IT MAY BE TO REALIZE FORECAST
HIGHS IN THE MID-UPPER 60S...BUT NOT GOING TO MESS WITH INHERITED
TEMP FORECAST FOR AT LEAST A FEW MORE HOURS. ALSO NO CHANGES MADE
TO LOW-END AFTERNOON THUNDERSTORM CHANCES AT THIS TIME...ALTHOUGH
QUICK GLANCE AT 10Z HRRR AND 00Z 4KM WRF-NMM SUGGEST THE BEST
CHANCES WILL TARGET MAINLY THE WESTERN 1/3 OF THE CWA LATE THIS
AFTERNOON INTO THIS EVENING.
PREV DISCUSSION... /ISSUED 624 AM CDT SUN APR 29 2012/
AVIATION...12Z TAF. SOME LIGHT FOG/MIST HAS SPREAD INTO THE KGRI
TERMINAL AREA AND IS RESTRICTING VISIBILITIES. THE VISIBILITY
SHOULD IMPROVE AS THE LOWER STRATUS MOVES INTO THE AREA IN THE
NEXT HOUR OR SO. EITHER WAY THERE WILL BE IFR CONDITIONS ARE
EXPECTED. BY MID DAY VFR CONDITIONS ARE EXPECTED AGAIN AS THE
CLOUDS RECEDE FROM THE AREA. LATE TONIGHT EXPECT IFR CONDITIONS
AGAIN WITH LOW LEVEL MOISTURE AND LIGHT WINDS.
PREV DISCUSSION... /ISSUED 323 AM CDT SUN APR 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. SMALL AREA OF LIGHT
SHOWERS/SPRINKLES OVER SOUTHWEST KS EARLY THIS MORNING SEEMS TO BE
ASSOCIATED WITH THE UPPER LEVEL JET DYNAMICS/DIFFLUENCE. DEPENDING
ON THE MODEL...ONE BRINGS THIS AREA OF SPRINKLES INTO OUR CWA
AROUND SUNRISE...THE OTHERS SUGGEST IT WILL STAY SOUTH. ALL THE
MODELS SHOW OUR CWA IN A RELATIVELY RAIN FREE AREA THROUGH TUESDAY
AFTERNOON. SEVERAL WEAK WAVES MOVING OVER THE AREA...SO EVEN
THOUGH CHANCES OF RAIN ARE LOW...THERE IS A CHANCE NONE THE LESS.
IN SHORT...TWEAKED PROBABILITY OF PRECIP AND A TEMP GRID HERE AND
THERE...BUT ON GOING FORECAST LOOKS FINE FOR NOW.
WILL HAVE TO WATCH FOR SOME POTENTIAL SEVERE WEATHER/THUNDERSTORM
DEVELOPMENT TUESDAY NIGHT THROUGH WEDNESDAY MORNING AS THERE IS
SOME INDICATION OF RAPID DESTABILIZATION OF THE ATMOSPHERE AS A
WARM FRONT MOVES INTO THE AREA. WILL NOT MENTION AT THIS TIME AS
CONFIDENCE IS LOW ALL THE INGREDIENTS WILL COME TOGETHER AS FORECAST.
MILD TEMPS TO CONTINUE THROUGH THE PERIOD. TODAY PROBABLY THE
COOLEST DAY THEN WARMING TO 10 TO 15 DEGREES ABOVE NORMAL BY MID WEEK.
LONG TERM...12Z WEDNESDAY THROUGH SATURDAY. MAIN FORECAST CONCERNS
WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS AND TEMPERATURES.
NEARLY ZONAL FLOW CONTINUES THROUGH THE PERIOD AND WITH IT THERE ARE
SEVERAL WAVES THAT MOVE THROUGH THE FLOW. MODELS CONTINUE TO HAVE
MINOR DIFFERENCES IN THE TIMING OF THESE WEAK WAVES AND THE SURFACE
SYSTEMS THAT MOVE THROUGH. THE LATEST RUNS OF THE MODELS HAVE A
SURFACE LOW AND COLD FRONT MOVING THROUGH WEDNESDAY NIGHT AND HAVE
KEPT A CHANCE FOR SHOWERS AND THUNDERSTORMS. WITHOUT A DEFINED
SURFACE BOUNDARY FOR THURSDAY THROUGH FRIDAY NIGHT HAVE KEPT DRY
CONDITIONS ACROSS THE AREA. BOTH THE GFS AND ECMWF DEVELOP ANOTHER
SURFACE LOW FOR SATURDAY MAINLY TO THE WEST OF THE FORECAST AREA.
WILL HAVE SOME CHANCES IN THE WEST/NORTHWEST. TEMPERATURES SHOULD BE
RATHER MILD WITH READINGS ABOVE NORMAL FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATES/AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1155 AM CDT SUN APR 29 2012
.UPDATE...JUST COMPLETED AN UPDATE FOR THIS AFTERNOON...ALTHOUGH
ADMITTEDLY CONFIDENCE IS A BIT LOW IN THE DETAILS. IN
SHORT...SPLIT THE LOW-END RISKS FOR A FEW THUNDERSTORMS INTO TWO
AREAS...ONE MAINLY EAST OF A YORK-OSBORNE LINE ASSOCIATED WITH THE
WEAK CONVECTION EVIDENT ON RADAR NOW AFFECTING THE HEBRON AREA AND
TIED TO AN EXITING SHORTWAVE...AND THE OTHER AREA FOR LATER THIS
AFTERNOON GENERALLY WEST OF AN ORD-PLAINVILLE LINE...WHERE BOTH
THE NAM/RUC ADVERTISE AT LEAST SEVERAL HUNDRED J/KG OF SBCAPE
DEVELOPING AS MODEST FORCING INCREASES AHEAD OF THE NEXT BATCH OF
SHORTWAVE ENERGY MOVING IN FROM THE WEST. ALTHOUGH NOT
ANTICIPATING SEVERE STORMS IN THE WESTERN AREA...COULD EASILY
FORESEE A FEW STRONG STORMS WITH DIME-NICKEL HAIL AND 50 MPH WIND
POTENTIAL. ALTHOUGH THE MAJORITY OF THE CWA WILL LIKELY REMAIN
DRY THIS AFTERNOON...DECIDED TO AT LEAST THROW A TOKEN SLIGHT
CHANCE OF A SPRINKLE ALL AREAS. OTHERWISE...CLOUD AND RESULTANT
TEMP TRENDS FOR THIS AFTERNOON ARE ALSO QUITE TRICKY. GENERAL
EXPECTATION IS THAT AT LEAST PARTIAL CLEARING WILL CONTINUE
WORKING INTO THE CWA FROM WEST-EAST...BUT WITH EASTERN AREAS
POSSIBLY STRUGGLING TO BREAK OUT OF LOW STRATUS EVEN BY LATER THIS
AFTERNOON. CURRENT SATELLITE IMAGERY REVEALS A BIT SHARPER
CLEARING LINE THAN EARLIER EXPECTED ACROSS THE WESTERN 1/2 OF THE
CWA. AS A RESULT...LEFT AFTERNOON HIGHS IN WESTERN COUNTIES
ESSENTIALLY UNCHANGED FROM PREVIOUS FORECAST...WITH MID-UPPER 60S.
HOWEVER...LOWERED EASTERN NEB ZONES A SOLID 2-4 DEGREES WITH SOME
PLACES POSSIBLY STRUGGLING TO REACH LOW 60S. IN BETWEEN...THE TRI-
CITIES ARE A TOUGH CALL...BUT WILL AIM FOR A 62-65 RANGE. NO
NOTABLE CHANGES MADE BEYOND THIS AFTERNOON YET.
&&
.PREV DISCUSSION... /ISSUED 835 AM CDT SUN APR 29 2012/
UPDATE...JUST STARTING TO GET A HANDLE ON TRENDS FOR TODAY...BUT
FIRST ORDER OF BUSINESS WAS UPDATING TO EXTEND COVERAGE OF FOG
WELL INTO THE MORNING HOURS...INCLUDING A MENTION OF PATCHY DENSE
FOG ACROSS A GOOD PERCENTAGE OF MAINLY THE CENTRAL/EASTERN CWA
BASED ON AUTOMATED OBS AND NDOR WEB CAMS. GLANCING AT BOUNDARY
LAYER RH PROGS FROM VARIOUS MODELS...LOW STRATUS AND FOG COULD BE
FAIRLY SLOW TO BURN OFF TODAY...ESPECIALLY ACROSS PARTS OF THE
SOUTHEAST 1/3 OR SO OF THE CWA. OBVIOUSLY THE LONGER FOG AND/OR
LOW STRATUS LINGERS...THE HARDER IT MAY BE TO REALIZE FORECAST
HIGHS IN THE MID-UPPER 60S...BUT NOT GOING TO MESS WITH INHERITED
TEMP FORECAST FOR AT LEAST A FEW MORE HOURS. ALSO NO CHANGES MADE
TO LOW-END AFTERNOON THUNDERSTORM CHANCES AT THIS TIME...ALTHOUGH
QUICK GLANCE AT 10Z HRRR AND 00Z 4KM WRF-NMM SUGGEST THE BEST
CHANCES WILL TARGET MAINLY THE WESTERN 1/3 OF THE CWA LATE THIS
AFTERNOON INTO THIS EVENING.
PREV DISCUSSION... /ISSUED 624 AM CDT SUN APR 29 2012/
AVIATION...12Z TAF. SOME LIGHT FOG/MIST HAS SPREAD INTO THE KGRI
TERMINAL AREA AND IS RESTRICTING VISIBILITIES. THE VISIBILITY
SHOULD IMPROVE AS THE LOWER STRATUS MOVES INTO THE AREA IN THE
NEXT HOUR OR SO. EITHER WAY THERE WILL BE IFR CONDITIONS ARE
EXPECTED. BY MID DAY VFR CONDITIONS ARE EXPECTED AGAIN AS THE
CLOUDS RECEDE FROM THE AREA. LATE TONIGHT EXPECT IFR CONDITIONS
AGAIN WITH LOW LEVEL MOISTURE AND LIGHT WINDS.
PREV DISCUSSION... /ISSUED 323 AM CDT SUN APR 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. SMALL AREA OF LIGHT
SHOWERS/SPRINKLES OVER SOUTHWEST KS EARLY THIS MORNING SEEMS TO BE
ASSOCIATED WITH THE UPPER LEVEL JET DYNAMICS/DIFFLUENCE. DEPENDING
ON THE MODEL...ONE BRINGS THIS AREA OF SPRINKLES INTO OUR CWA
AROUND SUNRISE...THE OTHERS SUGGEST IT WILL STAY SOUTH. ALL THE
MODELS SHOW OUR CWA IN A RELATIVELY RAIN FREE AREA THROUGH TUESDAY
AFTERNOON. SEVERAL WEAK WAVES MOVING OVER THE AREA...SO EVEN
THOUGH CHANCES OF RAIN ARE LOW...THERE IS A CHANCE NONE THE LESS.
IN SHORT...TWEAKED PROBABILITY OF PRECIP AND A TEMP GRID HERE AND
THERE...BUT ON GOING FORECAST LOOKS FINE FOR NOW.
WILL HAVE TO WATCH FOR SOME POTENTIAL SEVERE WEATHER/THUNDERSTORM
DEVELOPMENT TUESDAY NIGHT THROUGH WEDNESDAY MORNING AS THERE IS
SOME INDICATION OF RAPID DESTABILIZATION OF THE ATMOSPHERE AS A
WARM FRONT MOVES INTO THE AREA. WILL NOT MENTION AT THIS TIME AS
CONFIDENCE IS LOW ALL THE INGREDIENTS WILL COME TOGETHER AS FORECAST.
MILD TEMPS TO CONTINUE THROUGH THE PERIOD. TODAY PROBABLY THE
COOLEST DAY THEN WARMING TO 10 TO 15 DEGREES ABOVE NORMAL BY MID WEEK.
LONG TERM...12Z WEDNESDAY THROUGH SATURDAY. MAIN FORECAST CONCERNS
WILL BE CHANCES FOR SHOWERS AND THUNDERSTORMS AND TEMPERATURES.
NEARLY ZONAL FLOW CONTINUES THROUGH THE PERIOD AND WITH IT THERE ARE
SEVERAL WAVES THAT MOVE THROUGH THE FLOW. MODELS CONTINUE TO HAVE
MINOR DIFFERENCES IN THE TIMING OF THESE WEAK WAVES AND THE SURFACE
SYSTEMS THAT MOVE THROUGH. THE LATEST RUNS OF THE MODELS HAVE A
SURFACE LOW AND COLD FRONT MOVING THROUGH WEDNESDAY NIGHT AND HAVE
KEPT A CHANCE FOR SHOWERS AND THUNDERSTORMS. WITHOUT A DEFINED
SURFACE BOUNDARY FOR THURSDAY THROUGH FRIDAY NIGHT HAVE KEPT DRY
CONDITIONS ACROSS THE AREA. BOTH THE GFS AND ECMWF DEVELOP ANOTHER
SURFACE LOW FOR SATURDAY MAINLY TO THE WEST OF THE FORECAST AREA.
WILL HAVE SOME CHANCES IN THE WEST/NORTHWEST. TEMPERATURES SHOULD BE
RATHER MILD WITH READINGS ABOVE NORMAL FOR THIS TIME OF YEAR.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATES...PFANNKUCH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
347 PM EDT SUN APR 29 2012
.SYNOPSIS...
A STALLED FRONT OVER SOUTH CAROLINA WILL RETURN NORTHWARD AS A WARM
FRONT OVER WESTERN PORTIONS OF THE STATE THIS AFTERNOON AND EVENING
AS HIGH PRESSURE STRENGTHENS AND PROGRESSES SOUTHWARD ALONG THE MID
ATLANTIC COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM SUNDAY...
OVERVIEW:
AN H5 RIDGE CENTERED OVER THE WESTERN TN/OH VALLEYS AT 15Z WILL
PROGRESS EASTWARD TO THE SPINE OF THE APPALACHIANS BY 00-06Z
TONIGHT...RESULTING IN MODEST H5 HEIGHT RISES OVER THE MID-ATLANTIC
TODAY/TONIGHT. A SURFACE RIDGE AXIS EXTENDING SOUTH FROM THE
MID-ATLANTIC INTO THE CAROLINAS AT 15Z WILL WEAKEN IN WESTERN
PORTIONS OF THE STATE WHERE A WEAK TROUGH WILL DEVELOP. HOWEVER...
THE SURFACE RIDGE AXIS WILL STRENGTHEN TODAY/TONIGHT IN EASTERN
PORTIONS OF THE STATE IN ASSOC/W PRESSURE RISES ALONG THE MID-
ATLANTIC COAST...DUE TO HEIGHT RISES/SUBSIDENCE ALOFT IN ADVANCE OF
THE AFOREMENTIONED RIDGE. A SURFACE FRONT STALLED JUST S/SE OF THE
AREA OVER CENTRAL/SOUTHERN SOUTH CAROLINA AT 15Z IS PROGGED TO
ASSUME A NW-SE ORIENTATION TODAY/TONIGHT...LIFTING NORTHWARD INTO
PORTIONS OF THE WESTERN NC PIEDMONT/FOOTHILLS AND EXTENDING
SOUTHEAST IN VICINITY OF CAPE FEAR/WILMINGTON.
PRECIP CHANCES THIS AFT/EVE:
A WEAK UPPER LEVEL DISTURBANCE WAS NOTED IN WV IMAGERY/RUC DATA IN
SOUTHWEST VA AT 15Z. THE LATEST RUC SHOWS THIS FEATURE PROGRESSING
SOUTHEAST VIA NW FLOW ALOFT THROUGH THE NORTHEAST COASTAL PLAIN BY
18-21Z AND OFFSHORE THE NC OBX BY 21-00Z. GIVEN UNFAVORABLE
THERMODYNAMICS IN ADVANCE OF THIS FEATURE IN THE COASTAL PLAIN
(CLOUDY/COOL/STABLE) THROUGH 18-21Z...EXPECT DRY CONDITIONS TO
PREVAIL EAST OF HWY 1 THIS AFT/EVE. MODERATE INSTABILITY IS EXPECTED
THIS AFTERNOON IN FAR WESTERN PORTIONS OF THE STATE...THOUGH MLCAPE
VALUES SHOULD REMAIN ON THE MARGINAL SIDE (500-1000 J/KG) IN THE
WESTERN PIEDMONT...CLOSER TO THE DRIER SFC RIDGE AXIS TO THE EAST.
DESTABILIZATION IN THE WEST WILL BE AIDED BY INCREASING BOUNDARY
LAYER MOISTURE (ASSOC/W THE FRONT PROGRESSING NORTHWARD INTO WESTERN
NC) IN THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) AND
CLEAR SKIES. HOWEVER...SUBSIDENCE IN THE WAKE OF THE AFOREMENTIONED
UPPER LEVEL DISTURBANCE ALONG WITH WEAK SYNOPTIC HEIGHT RISES IN
ADVANCE OF THE H5 RIDGE APPROACHING FROM THE WEST WILL BE
UNSUPPORTIVE OF PRECIP...AND LOW-LEVEL FORCING WILL BE CONFINED TO
BROAD WARM ADVECTION AND WEAK/SHALLOW LOW-LEVEL CONVERGENCE...WITH
THE RELATIVE BEST LOW-LEVEL FORCING CONFINED WEST OF I-77. IF ISOLD
CONVECTION DEVELOPS IN THE MOUNTAINS/FOOTHILLS AFTER 21Z...IT IS
CONCEIVABLE THAT IT COULD PROGRESS EAST/SE INTO PORTIONS OF THE NW
PIEDMONT BETWEEN 21-02Z THIS AFT/EVE VIA SPEEDY WESTERLY/WNW FLOW
ALOFT. THE LATEST 12Z WRF-NMM INDICATES THIS SCENARIO IS AT LEAST
POSSIBLE...AND WITH THAT IN MIND...WILL INTRODUCE A SLIGHT CHANCE OF
SHOWERS/STORMS TO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE.
IT IS INTERESTING THAT SUFFICIENT INSTABILITY AND 0-6 KM SHEAR MAY
BE PRESENT ON THE EASTERN PERIPHERY OF THE H5 RIDGE IN THE WESTERN
PIEDMONT TO SUPPORT A VERY LOW-END CONDITIONAL SEVERE THREAT LATER
THIS AFT/EVE...THOUGH A PROFOUND LACK OF FORCING AND THE PRESENCE OF
A DRY AIRMASS ALOFT (ASSOC/W AN EML EXTENDING EAST INTO THE AREA)
WILL MAKE IT DIFFICULT FOR ANY UPDRAFTS TO SURVIVE/PERSIST... SHOULD
ANY DEVELOP OR ADVECT INTO THE WESTERN PIEDMONT IN THE FIRST PLACE.
PRECIP CHANCES TONIGHT:
AS THE H5 RIDGE AXIS PROGRESSES EAST TO THE SPINE OF THE
APPALACHIANS TONIGHT...IT WILL BECOME INCREASINGLY DIFFICULT FOR ANY
UPSTREAM SHORTWAVES/MCVS (PROGRESSING EAST ATOP THE RIDGE) TO TRACK
INTO CENTRAL NC...WITH A MORE LIKELY TRACK FURTHER NORTH IN THE
MID-ATLANTIC. AS A RESULT...LITTLE OR NO UPPER SUPPORT WILL BE
PRESENT OVERNIGHT...THOUGH WEAK LOW-LEVEL WARM ADVECTION WILL BE
PRESENT. GIVEN THE CONTINUED PRESENCE OF AN ELEVATED MIXED LAYER
(ALBEIT MODIFIED)...EXPECT AT LEAST MARGINAL ELEVATED INSTABILITY TO
BE PRESENT OVERNIGHT. WITH THE ABOVE IN MIND...WILL CONTINUE TO
INDICATE A SLIGHT CHANCE OF SHOWERS OVERNIGHT IN ASSOC/W WARM
ADVECTION IN THE PRESENCE OF ELEVATED INSTABILITY. THUNDER CANNOT BE
RULED OUT...PRIMARILY IN THE WEST/NW PIEDMONT...THOUGH IT SEEMS
UNLIKELY IN THE ABSENCE OF ANY UPPER LEVEL SUPPORT.
LOWS TONIGHT:
AS THE SFC-H85 RIDGE STRENGTHENS OVER EASTERN NC/VA TONIGHT...
LOW-LEVEL FLOW WILL VEER TO THE EAST/SE AND ADVECT A MOIST MARITIME
AIRMASS INTO CENTRAL NC. WIDESPREAD LOW CLOUD COVER IS EXPECTED TO
ADVECT INTO OR RE-DEVELOP OVER THE AREA...THICKER/LOWER WEST OF I-95
IN CLOSER PROXIMITY TO BETTER LOW-LEVEL MOISTURE IN VICINITY OF THE
AFOREMENTIONED FRONTAL ZONE. EXPECT LOWS TO RANGE FROM THE MID/UPPER
50S EAST OF I-95 CENTRAL/NE COASTAL PLAIN TO THE UPPER 50S AND LOWER
60S ELSEWHERE...WARMEST SANDHILLS AND WEST/SW PIEDMONT. -VINCENT
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 345 PM SUNDAY...
OVERVIEW:
THE H5 RIDGE AXIS WILL PROGRESS EAST INTO THE MID-ATLANTIC AND
CAROLINAS ON MONDAY AS SHORTWAVE ENERGY TRACKS NORTHEAST THROUGH THE
GREAT LAKES INTO CANADA. THE RIDGE IS PROGGED TO WEAKEN MONDAY NIGHT
AS ADDITIONAL SHORTWAVE ENERGY PROGRESSES INTO THE MID-ATLANTIC FROM
THE SOUTHWEST. CENTRAL NC WILL BE ON THE NORTHERN PERIPHERY OF THE
RIDGE (CENTERED OVER THE DEEP SOUTH/SOUTHEAST STATES) ON MONDAY...IN
THE PRESENCE OF WESTERLY FLOW ALOFT. WESTERLY FLOW ALOFT WILL
STRENGTHEN MONDAY NIGHT AS THE RIDGE WEAKENS AND THE HEIGHT GRADIENT
TIGHTENS FROM THE NORTH. IN THE LOWER LEVELS...A LOW PRESSURE SYSTEM
TRACKING NORTHEAST THROUGH THE GREAT LAKES WILL PUSH HIGH PRESSURE
OFFSHORE THE MID-ATLANTIC/CAROLINA COAST ON MONDAY. THE RESULTING
SOUTHERLY RETURN FLOW WILL ALLOW THE NW-SE ORIENTED FRONTAL ZONE IN
IN PLACE OVER THE AREA TONIGHT TO MOVE NORTHEAST THROUGH THE ENTIRE
AREA AS A WARM FRONT DURING THE DAY MONDAY...WITH A WARM/MOIST
SOUTHERLY RETURN FLOW PERSISTING MONDAY NIGHT.
TEMPERATURES:
CHALLENGING FCST. EXPANSIVE LOW-LEVEL CLOUD COVER IS EXPECTED TO BE
IN PLACE SUNRISE MONDAY MORNING. FORECAST SOUNDINGS INDICATE THAT
THIS LOW STRATUS MAY TAKE AT LEAST SEVERAL HOURS TO LIFT AND SCATTER
OUT...PERHAPS NOT UNTIL 18-21Z IN SOME LOCATIONS. HIGH TEMPS WILL
DEPEND PRIMARILY ON THE TIMING OF CLOUD COVER EROSION. 1000-850 MB
THICKNESSES ARE PROGGED TO BE IN THE 1390-1405 METER RANGE ON
MONDAY... LOWEST NE COASTAL PLAIN AND HIGHEST W/SW PIEDMONT. AT THIS
TIME...WILL INDICATE HIGHS RANGING FROM THE MID 70S NE TO UPPER 70S/
LOWER 80S (76-81F) ELSEWHERE...WARMEST IN THE FAR SE PIEDMONT. GIVEN
WARM ADVECTION AND THE EXPECTED DEVELOPMENT OF LOW STRATUS AGAIN IN
MOST LOCATIONS MONDAY NIGHT...ANTICIPATE WARMER LOW TEMPERATURES...
IN THE LOWER 60S.
PRECIPITATION CHANCES:
DIFFICULT PRECIP FCST. DIURNAL DESTABILIZATION ON MONDAY WILL HIGHLY
DEPEND ON WHEN EXPANSIVE LOW-LEVEL CLOUD COVER LIFTS/SCATTERS OUT
AND WHERE THE BEST BOUNDARY LAYER MOISTURE WILL BE PRESENT IN THE
WAKE OF THE WARM FRONT PROGRESSING NE/NNE THROUGH THE AREA. GIVEN
THAT THE WARM FRONT WILL PROGRESS THROUGH THE WEST/SW PIEDMONT
FIRST...AREAS WEST OF HIGHWAY 1 WILL DESTABILIZE THE MOST ON MONDAY.
MODEL GUIDANCE IS INDICATING MLCAPE VALUES AS HIGH AS 1500-2000 J/KG
IN THE WESTERN PIEDMONT...OWING TO TEMPS IN THE UPPER 70S AND
DEWPOINTS IN THE LOWER 60S IN THE PRESENCE OF A MODIFIED EML WITH
MID-LEVEL LAPSE RATES ON THE ORDER OF 7-7.5 C/KM. FURTHER EAST WHERE
BOUNDARY LAYER MOISTURE WILL BE LOWER...MLCAPE VALUES WILL GENERALLY
RANGE FROM 500-1500 J/KG. W/REGARD TO FORCING...ALTHOUGH AN H5 RIDGE
AXIS WILL EXTEND NORTHWARD (FROM GA/FL) INTO THE CAROLINAS/
MID-ATLANTIC ON MONDAY...CENTRAL NC WILL REMAIN ON THE NORTHERN
PERIPHERY OF THE RIDGE IN WESTERLY FLOW ALOFT...AND SOME UPPER
FORCING IN THE FORM OF MINOR SHORTWAVES WILL BE POSSIBLE.
HOWEVER...THE TIMING AND EVOLUTION OF THESE FEATURES ARE DIFFICULT
TO ANTICIPATE AT THIS TIME. GIVEN A PATTERN OF SOUTHERLY/SE RETURN
FLOW...LOW-LEVEL FORCING WILL BE CONFINED TO UPSLOPE FLOW IN THE
FOOTHILLS/MOUNTAINS...AND TO THE SEABREEZE AND/OR DIFFERENTIAL
HEATING BOUNDARIES IN CENTRAL/EASTERN NC. GIVEN A FAIR AMOUNT OF
UNCERTAINTY W/REGARD TO WHETHER OR NOT SUFFICIENT FORCING WILL BE
PRESENT...WILL INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS OVER THE
ENTIRE AREA MON AFT/EVE. FOR MONDAY NIGHT...GIVEN AN OVERALL LACK OF
FORCING AND A RELATIVELY LESS FAVORABLE (THAN TONIGHT) THERMODYNAMIC
ENVIRONMENT (I.E. VERY LITTLE IF ANY ELEVATED INSTABILITY)... HAVE
OPTED TO KEEP THE FCST DRY. -VINCENT
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 301 PM SUNDAY...
...SUMMER-LIKE TEMPERATURES AND HUMIDITIES EXPECTED TUESDAY THROUGH
THE END OF THE WEEK...
AS WE BEGIN A NEW MONTH ON TUESDAY... IT WILL BE LIKE FLIPPING A
SWITCH FROM MILD TO HOT. THE OVERALL MID-UPPER LEVEL FLOW PATTERN IS
A HIGH CONFIDENCE FORECAST FOR THE REGION AS MODELS ARE IN EXCELLENT
AGREEMENT IN THE DEVELOPMENT OF A MODERATELY STRONG UPPER LEVEL
RIDGE OVER THE SOUTHEASTERN UNITED STATES TUESDAY AND WEDNESDAY.
THE UPPER RIDGE IS FORECAST TO PERSIST WELL INTO THE END OF THE
WEEK. THE UPPER RIDGE AXIS IS FORECAST TO PEAK OVER NC/SC BY
WEDNESDAY INTO THURSDAY... THEN SHIFT WESTWARD IN TIME FRIDAY INTO
SUNDAY. THE BOTTOM LINE... EXPECT A DRAMATIC SHIFT FROM MILD AND
MOIST CONDITIONS FROM THE PAST FEW WEEKS... TO SUMMERTIME CONDITIONS
TUESDAY THROUGH THE REST OF THE WEEK.
THERE ARE INDICATIONS THAT THE HOT/HUMID WEATHER WILL LAST 5-6
DAYS... THEN IT SHOULD BE FOLLOWED BY A SIGNIFICANT COOL DOWN LATE
NEXT WEEKEND OR AROUND MAY 6-9. (IF THE MODELS ARE CORRECT IN THE
LONGER TERM FORECAST SHIFT IN THE UPPER RIDGE WESTWARD BACK TO THE
PLAINS - ALLOWING THE CARVING OUT OF A H5 TROUGH ALONG THE EASTERN
SEABOARD).
THEREFORE THIS WEEK... EXPECT HOT AND UNSEASONABLY HUMID
CONDITIONS... WITH ONLY A SLIGHT CHANCE OF AN AFTERNOON OR EVENING
THUNDERSTORM BEYOND TUESDAY.
SENSIBLE WEATHER WILL START WITH CONDITIONS BECOMING VERY WARM AND
HUMID TUESDAY AS THE LEAD WARM FRONT LIFTS NORTH OF OUR REGION.
THERE IS A POTENTIAL FOR SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS AS MODELS INDICATE THE POTENTIAL FOR A VORTICITY
MAXIMUM TO RIDE A TOP THE BUILDING MID-UPPER LEVEL RIDGE OVER NC/VA
DURING MAXIMUM HEATING. FOR NOW... IT IS TOO EARLY TO LATCH ONTO
SUCH A FEATURE WITH ANY CONFIDENCE IN THE MODELS. HOWEVER... THIS
POTENTIAL WILL BE WATCHED. OTHERWISE... DIFFERENTIAL HEATING ALONG
THE EASTERN SLOPES OF THE MOUNTAINS SHOULD LEAD TO AT LEAST
SCATTERED THUNDERSTORMS TUESDAY AFTERNOON IN THE INCREASINGLY HUMID
BOUNDARY LAYER OVER NC/SW VA. SOME OF THESE MAY MOVE OFF OR DEVELOP
INTO THE PIEDMONT AS MODELS DO FAVOR A SURFACE TROUGH DEVELOPMENT IN
THE PIEDMONT DURING THE AFTERNOON. HIGHS WILL SOAR INTO THE MID TO
UPPER 80S. DEW POINTS SHOULD RISE TO BETWEEN 60-65... MAKING IT FEEL
LIKE JUNE OR EARLY JULY. WE WILL FORECAST 20-30 POP AND WAIT/SEE HOW
THE MODELS FORECAST ANY VORT MAX FOR TUESDAY TO AID IN CONVECTIVE
POTENTIAL.
AFTER THE SCATTERED CONVECTION POTENTIAL ENDS TUESDAY EVENING... WE
EXPECT THE MID-UPPER LEVEL RIDGING TO BE STRONG ENOUGH TO SUPPRESS
CONVECTIVE DEVELOPMENT IN THE ABSENCE OF ANY FOCUSING MECHANISMS
EVEN WITH DECENT LOW LEVEL MOISTURE AND HEAT. EXPECT GENERALLY WARM
DRY SUBSIDENCE IN THE MID LEVELS. WEDNESDAY THROUGH FRIDAY... MOSTLY
CLEAR MILD NIGHTS AND MOSTLY SUNNY HOT DAYS. DAILY TEMPERATURES
SHOULD AVERAGE A GOOD 10 DEGREES ABOVE NORMAL. NIGHTTIME LOWS A GOOD
10-15 DEGREES ABOVE NORMAL. LOWS SHOULD BE IN THE LOWER TO MID 60S
EACH DAY. HIGHS GENERALLY IN THE 85-90 RANGE.
SATURDAY AND SUNDAY... THE MID-UPPER HEIGHTS ARE FORECAST TO BEGIN
TO LOWER SOMEWHAT OVER THE SE WHICH SHOULD ALLOW DAILY TEMPERATURES
TO BACK OFF A FEW DEGREES. THE CHANCE OF CONVECTION SHOULD INCREASE
AT SOME POINT AS THE TROUGH DEVELOPS. HOWEVER... WE WILL KEEP ANY
MENTION OF SHOWERS OR THUNDERSTORMS ISOLATED... AND MAINLY LATE DAY
UNTIL A MORE DEFINITIVE TIMING OF AN ACTUAL COLD FRONT OR OTHER
FOCUS CAN BE PROJECTED. LOWS IN THE MID 60S. HIGHS IN THE LOWER TO
MID 80S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 230 PM SUNDAY...
24-HR TAF PERIOD:
ASIDE FROM LINGERING MVFR CEILINGS AT THE FAY/RWI TAF SITES THIS
AFTERNOON...VFR CONDITIONS ARE EXPECTED THROUGH 00Z THIS EVENING.
TONIGHT...LOW-LEVEL MOISTURE WILL CONTINUE TO INCREASE IN VICINITY
OF A FRONTAL ZONE OVER THE FAR WESTERN PIEDMONT AND FOOTHILLS.
ADDITIONALLY...LOW-LEVEL FLOW WILL VEER TO THE EAST/SE...ALLOWING A
MOIST MARITIME AIRMASS TO PROGRESS WESTWARD INTO CENTRAL NC. AS A
RESULT...CONDITIONS ARE EXPECTED TO DETERIORATE AT ALL TAF SITES BY
03-07Z IN ASSOCIATION WITH THE EXPECTED DEVELOPMENT OF MVFR/IFR
CEILINGS. THE HIGHEST LIKELIHOOD OF IFR (AND PERHAPS LIFR) CEILINGS
WILL BE ALONG/WEST OF HIGHWAY 1...OR AT THE FAY/RDU/INT/GSO TAF
SITES. CONDITIONS ARE EXPECTED TO BE SLOW TO IMPROVE ON MONDAY...
WITH CEILINGS GRADUALLY LIFTING FROM IFR TO MVFR BY 18Z...AND FROM
MVFR TO VFR BY 21Z...THOUGH MVFR CEILINGS MAY PERSIST THROUGH SUNSET
IN SOME LOCATIONS.
LOOKING AHEAD:
MVFR/IFR STRATUS WILL BE POSSIBLE AGAIN TUESDAY MORNING...PRIMARILY
BETWEEN 06-12Z. ANY STRATUS THAT DEVELOPS IS EXPECTED TO RAPIDLY MIX
OUT AFTER SUNRISE TUE MORNING. ASIDE FROM A SMALL CHANCE FOR SHOWERS
AND STORMS EACH DAY THIS WEEK...VFR CONDITIONS ARE GENERALLY
EXPECTED TO PREDOMINATE. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
302 PM EDT SUN APR 29 2012
.SYNOPSIS...
A STALLED FRONT OVER SOUTH CAROLINA WILL RETURN NORTHWARD AS A WARM
FRONT OVER WESTERN PORTIONS OF THE STATE THIS AFTERNOON AND EVENING
AS HIGH PRESSURE STRENGTHENS AND PROGRESSES SOUTHWARD ALONG THE MID
ATLANTIC COAST.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 100 PM SUNDAY...
OVERVIEW:
AN H5 RIDGE CENTERED OVER THE WESTERN TN/OH VALLEYS AT 15Z WILL
PROGRESS EASTWARD TO THE SPINE OF THE APPALACHIANS BY 00-06Z
TONIGHT...RESULTING IN MODEST H5 HEIGHT RISES OVER THE MID-ATLANTIC
TODAY/TONIGHT. A SURFACE RIDGE AXIS EXTENDING SOUTH FROM THE
MID-ATLANTIC INTO THE CAROLINAS AT 15Z WILL WEAKEN IN WESTERN
PORTIONS OF THE STATE WHERE A WEAK TROUGH WILL DEVELOP. HOWEVER...
THE SURFACE RIDGE AXIS WILL STRENGTHEN TODAY/TONIGHT IN EASTERN
PORTIONS OF THE STATE IN ASSOC/W PRESSURE RISES ALONG THE MID-
ATLANTIC COAST...DUE TO HEIGHT RISES/SUBSIDENCE ALOFT IN ADVANCE OF
THE AFOREMENTIONED RIDGE. A SURFACE FRONT STALLED JUST S/SE OF THE
AREA OVER CENTRAL/SOUTHERN SOUTH CAROLINA AT 15Z IS PROGGED TO
ASSUME A NW-SE ORIENTATION TODAY/TONIGHT...LIFTING NORTHWARD INTO
PORTIONS OF THE WESTERN NC PIEDMONT/FOOTHILLS AND EXTENDING
SOUTHEAST IN VICINITY OF CAPE FEAR/WILMINGTON.
TEMPERATURES:
AS THE SFC-H85 RIDGE STRENGTHENS OVER EASTERN NC/VA TONIGHT...
LOW-LEVEL FLOW WILL VEER TO THE EAST/SE AND ADVECT A MOIST MARITIME
AIRMASS INTO CENTRAL NC. WIDESPREAD LOW CLOUD COVER IS EXPECTED TO
ADVECT INTO OR RE-DEVELOP OVER THE AREA...THICKER/LOWER WEST OF I-95
IN CLOSER PROXIMITY TO BETTER LOW-LEVEL MOISTURE IN VICINITY OF THE
AFOREMENTIONED FRONTAL ZONE. EXPECT LOWS TO RANGE FROM THE MID/UPPER
50S EAST OF I-95 CENTRAL/NE COASTAL PLAIN TO THE UPPER 50S AND LOWER
60S ELSEWHERE...WARMEST SANDHILLS AND WEST/SW PIEDMONT.
PRECIP CHANCES THIS AFT/EVE:
A WEAK UPPER LEVEL DISTURBANCE WAS NOTED IN WV IMAGERY/RUC DATA IN
SOUTHWEST VA AT 15Z. THE LATEST RUC SHOWS THIS FEATURE PROGRESSING
SOUTHEAST VIA NW FLOW ALOFT THROUGH THE NORTHEAST COASTAL PLAIN BY
18-21Z AND OFFSHORE THE NC OBX BY 21-00Z. GIVEN UNFAVORABLE
THERMODYNAMICS IN ADVANCE OF THIS FEATURE IN THE COASTAL PLAIN
(CLOUDY/COOL/STABLE) THROUGH 18-21Z...EXPECT DRY CONDITIONS TO
PREVAIL EAST OF HWY 1 THIS AFT/EVE. MODERATE INSTABILITY IS EXPECTED
THIS AFTERNOON IN FAR WESTERN PORTIONS OF THE STATE...THOUGH MLCAPE
VALUES SHOULD REMAIN ON THE MARGINAL SIDE (500-1000 J/KG) IN THE
WESTERN PIEDMONT...CLOSER TO THE DRIER SFC RIDGE AXIS TO THE EAST.
DESTABILIZATION IN THE WEST WILL BE AIDED BY INCREASING BOUNDARY
LAYER MOISTURE (ASSOC/W THE FRONT PROGRESSING NORTHWARD INTO WESTERN
NC) IN THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) AND
CLEAR SKIES. HOWEVER...SUBSIDENCE IN THE WAKE OF THE AFOREMENTIONED
UPPER LEVEL DISTURBANCE ALONG WITH WEAK SYNOPTIC HEIGHT RISES IN
ADVANCE OF THE H5 RIDGE APPROACHING FROM THE WEST WILL BE
UNSUPPORTIVE OF PRECIP...AND LOW-LEVEL FORCING WILL BE CONFINED TO
BROAD WARM ADVECTION AND WEAK/SHALLOW LOW-LEVEL CONVERGENCE...WITH
THE RELATIVE BEST LOW-LEVEL FORCING CONFINED WEST OF I-77. IF ISOLD
CONVECTION DEVELOPS IN THE MOUNTAINS/FOOTHILLS AFTER 21Z...IT IS
CONCEIVABLE THAT IT COULD PROGRESS EAST/SE INTO PORTIONS OF THE NW
PIEDMONT BETWEEN 21-02Z THIS AFT/EVE VIA SPEEDY WESTERLY/WNW FLOW
ALOFT. THE LATEST 12Z WRF-NMM INDICATES THIS SCENARIO IS AT LEAST
POSSIBLE...AND WITH THAT IN MIND...WILL INTRODUCE A SLIGHT CHANCE OF
SHOWERS/STORMS TO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE.
IT IS INTERESTING THAT SUFFICIENT INSTABILITY AND 0-6 KM SHEAR MAY
BE PRESENT ON THE EASTERN PERIPHERY OF THE H5 RIDGE IN THE WESTERN
PIEDMONT TO SUPPORT A VERY LOW-END CONDITIONAL SEVERE THREAT LATER
THIS AFT/EVE...THOUGH A PROFOUND LACK OF FORCING AND THE PRESENCE OF
A DRY AIRMASS ALOFT (ASSOC/W AN EML EXTENDING EAST INTO THE AREA)
WILL MAKE IT DIFFICULT FOR ANY UPDRAFTS TO SURVIVE/PERSIST... SHOULD
ANY DEVELOP OR ADVECT INTO THE WESTERN PIEDMONT IN THE FIRST PLACE.
PRECIP CHANCES TONIGHT:
AS THE H5 RIDGE AXIS PROGRESSES EAST TO THE SPINE OF THE
APPALACHIANS TONIGHT...IT WILL BECOME INCREASINGLY DIFFICULT FOR ANY
UPSTREAM SHORTWAVES/MCVS (PROGRESSING EAST ATOP THE RIDGE) TO TRACK
INTO CENTRAL NC...WITH A MORE LIKELY TRACK FURTHER NORTH IN THE
MID-ATLANTIC. AS A RESULT...LITTLE OR NO UPPER SUPPORT WILL BE
PRESENT OVERNIGHT...THOUGH WEAK LOW-LEVEL WARM ADVECTION WILL BE
PRESENT. GIVEN THE CONTINUED PRESENCE OF AN ELEVATED MIXED LAYER
(ALBEIT MODIFIED)...EXPECT AT LEAST MARGINAL ELEVATED INSTABILITY TO
BE PRESENT OVERNIGHT. WITH THE ABOVE IN MIND...WILL CONTINUE TO
INDICATE A SLIGHT CHANCE OF SHOWERS OVERNIGHT IN ASSOC/W WARM
ADVECTION IN THE PRESENCE OF ELEVATED INSTABILITY. THUNDER CANNOT BE
RULED OUT...PRIMARILY IN THE WEST/NW PIEDMONT...THOUGH IT SEEMS
UNLIKELY IN THE ABSENCE OF ANY UPPER LEVEL SUPPORT. -VINCENT
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 230 AM SUNDAY...
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 301 PM SUNDAY...
...SUMMER-LIKE TEMPERATURES AND HUMIDITIES EXPECTED TUESDAY THROUGH
THE END OF THE WEEK...
AS WE BEGIN A NEW MONTH ON TUESDAY... IT WILL BE LIKE FLIPPING A
SWITCH FROM MILD TO HOT. THE OVERALL MID-UPPER LEVEL FLOW PATTERN IS
A HIGH CONFIDENCE FORECAST FOR THE REGION AS MODELS ARE IN EXCELLENT
AGREEMENT IN THE DEVELOPMENT OF A MODERATELY STRONG UPPER LEVEL
RIDGE OVER THE SOUTHEASTERN UNITED STATES TUESDAY AND WEDNESDAY.
THE UPPER RIDGE IS FORECAST TO PERSIST WELL INTO THE END OF THE
WEEK. THE UPPER RIDGE AXIS IS FORECAST TO PEAK OVER NC/SC BY
WEDNESDAY INTO THURSDAY... THEN SHIFT WESTWARD IN TIME FRIDAY INTO
SUNDAY. THE BOTTOM LINE... EXPECT A DRAMATIC SHIFT FROM MILD AND
MOIST CONDITIONS FROM THE PAST FEW WEEKS... TO SUMMERTIME CONDITIONS
TUESDAY THROUGH THE REST OF THE WEEK.
THERE ARE INDICATIONS THAT THE HOT/HUMID WEATHER WILL LAST 5-6
DAYS... THEN IT SHOULD BE FOLLOWED BY A SIGNIFICANT COOL DOWN LATE
NEXT WEEKEND OR AROUND MAY 6-9. (IF THE MODELS ARE CORRECT IN THE
LONGER TERM FORECAST SHIFT IN THE UPPER RIDGE WESTWARD BACK TO THE
PLAINS - ALLOWING THE CARVING OUT OF A H5 TROUGH ALONG THE EASTERN
SEABOARD).
THEREFORE THIS WEEK... EXPECT HOT AND UNSEASONABLY HUMID
CONDITIONS... WITH ONLY A SLIGHT CHANCE OF AN AFTERNOON OR EVENING
THUNDERSTORM BEYOND TUESDAY.
SENSIBLE WEATHER WILL START WITH CONDITIONS BECOMING VERY WARM AND
HUMID TUESDAY AS THE LEAD WARM FRONT LIFTS NORTH OF OUR REGION.
THERE IS A POTENTIAL FOR SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS AS MODELS INDICATE THE POTENTIAL FOR A VORTICITY
MAXIMUM TO RIDE A TOP THE BUILDING MID-UPPER LEVEL RIDGE OVER NC/VA
DURING MAXIMUM HEATING. FOR NOW... IT IS TOO EARLY TO LATCH ONTO
SUCH A FEATURE WITH ANY CONFIDENCE IN THE MODELS. HOWEVER... THIS
POTENTIAL WILL BE WATCHED. OTHERWISE... DIFFERENTIAL HEATING ALONG
THE EASTERN SLOPES OF THE MOUNTAINS SHOULD LEAD TO AT LEAST
SCATTERED THUNDERSTORMS TUESDAY AFTERNOON IN THE INCREASINGLY HUMID
BOUNDARY LAYER OVER NC/SW VA. SOME OF THESE MAY MOVE OFF OR DEVELOP
INTO THE PIEDMONT AS MODELS DO FAVOR A SURFACE TROUGH DEVELOPMENT IN
THE PIEDMONT DURING THE AFTERNOON. HIGHS WILL SOAR INTO THE MID TO
UPPER 80S. DEW POINTS SHOULD RISE TO BETWEEN 60-65... MAKING IT FEEL
LIKE JUNE OR EARLY JULY. WE WILL FORECAST 20-30 POP AND WAIT/SEE HOW
THE MODELS FORECAST ANY VORT MAX FOR TUESDAY TO AID IN CONVECTIVE
POTENTIAL.
AFTER THE SCATTERED CONVECTION POTENTIAL ENDS TUESDAY EVENING... WE
EXPECT THE MID-UPPER LEVEL RIDGING TO BE STRONG ENOUGH TO SUPPRESS
CONVECTIVE DEVELOPMENT IN THE ABSENCE OF ANY FOCUSING MECHANISMS
EVEN WITH DECENT LOW LEVEL MOISTURE AND HEAT. EXPECT GENERALLY WARM
DRY SUBSIDENCE IN THE MID LEVELS. WEDNESDAY THROUGH FRIDAY... MOSTLY
CLEAR MILD NIGHTS AND MOSTLY SUNNY HOT DAYS. DAILY TEMPERATURES
SHOULD AVERAGE A GOOD 10 DEGREES ABOVE NORMAL. NIGHTTIME LOWS A GOOD
10-15 DEGREES ABOVE NORMAL. LOWS SHOULD BE IN THE LOWER TO MID 60S
EACH DAY. HIGHS GENERALLY IN THE 85-90 RANGE.
SATURDAY AND SUNDAY... THE MID-UPPER HEIGHTS ARE FORECAST TO BEGIN
TO LOWER SOMEWHAT OVER THE SE WHICH SHOULD ALLOW DAILY TEMPERATURES
TO BACK OFF A FEW DEGREES. THE CHANCE OF CONVECTION SHOULD INCREASE
AT SOME POINT AS THE TROUGH DEVELOPS. HOWEVER... WE WILL KEEP ANY
MENTION OF SHOWERS OR THUNDERSTORMS ISOLATED... AND MAINLY LATE DAY
UNTIL A MORE DEFINITIVE TIMING OF AN ACTUAL COLD FRONT OR OTHER
FOCUS CAN BE PROJECTED. LOWS IN THE MID 60S. HIGHS IN THE LOWER TO
MID 80S.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 230 PM SUNDAY...
24-HR TAF PERIOD:
ASIDE FROM LINGERING MVFR CEILINGS AT THE FAY/RWI TAF SITES THIS
AFTERNOON...VFR CONDITIONS ARE EXPECTED THROUGH 00Z THIS EVENING.
TONIGHT...LOW-LEVEL MOISTURE WILL CONTINUE TO INCREASE IN VICINITY
OF A FRONTAL ZONE OVER THE FAR WESTERN PIEDMONT AND FOOTHILLS.
ADDITIONALLY...LOW-LEVEL FLOW WILL VEER TO THE EAST/SE...ALLOWING A
MOIST MARITIME AIRMASS TO PROGRESS WESTWARD INTO CENTRAL NC. AS A
RESULT...CONDITIONS ARE EXPECTED TO DETERIORATE AT ALL TAF SITES BY
03-07Z IN ASSOCIATION WITH THE EXPECTED DEVELOPMENT OF MVFR/IFR
CEILINGS. THE HIGHEST LIKELIHOOD OF IFR (AND PERHAPS LIFR) CEILINGS
WILL BE ALONG/WEST OF HIGHWAY 1...OR AT THE FAY/RDU/INT/GSO TAF
SITES. CONDITIONS ARE EXPECTED TO BE SLOW TO IMPROVE ON MONDAY...
WITH CEILINGS GRADUALLY LIFTING FROM IFR TO MVFR BY 18Z...AND FROM
MVFR TO VFR BY 21Z...THOUGH MVFR CEILINGS MAY PERSIST THROUGH SUNSET
IN SOME LOCATIONS.
LOOKING AHEAD:
MVFR/IFR STRATUS WILL BE POSSIBLE AGAIN TUESDAY MORNING...PRIMARILY
BETWEEN 06-12Z. ANY STRATUS THAT DEVELOPS IS EXPECTED TO RAPIDLY MIX
OUT AFTER SUNRISE TUE MORNING. ASIDE FROM A SMALL CHANCE FOR SHOWERS
AND STORMS EACH DAY THIS WEEK...VFR CONDITIONS ARE GENERALLY
EXPECTED TO PREDOMINATE. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...SMITH/99
LONG TERM...BADGETT
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
301 PM EDT SUN APR 29 2012
.SYNOPSIS...
A STALLED FRONT OVER SOUTH CAROLINA WILL RETURN NORTHWARD AS A WARM
FRONT OVER WESTERN PORTIONS OF THE STATE THIS AFTERNOON AND EVENING
AS HIGH PRESSURE STRENGTHENS AND PROGRESSES SOUTHWARD ALONG THE MID
ATLANTIC COAST.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 100 PM SUNDAY...
OVERVIEW:
AN H5 RIDGE CENTERED OVER THE WESTERN TN/OH VALLEYS AT 15Z WILL
PROGRESS EASTWARD TO THE SPINE OF THE APPALACHIANS BY 00-06Z
TONIGHT...RESULTING IN MODEST H5 HEIGHT RISES OVER THE MID-ATLANTIC
TODAY/TONIGHT. A SURFACE RIDGE AXIS EXTENDING SOUTH FROM THE
MID-ATLANTIC INTO THE CAROLINAS AT 15Z WILL WEAKEN IN WESTERN
PORTIONS OF THE STATE WHERE A WEAK TROUGH WILL DEVELOP. HOWEVER...
THE SURFACE RIDGE AXIS WILL STRENGTHEN TODAY/TONIGHT IN EASTERN
PORTIONS OF THE STATE IN ASSOC/W PRESSURE RISES ALONG THE MID-
ATLANTIC COAST...DUE TO HEIGHT RISES/SUBSIDENCE ALOFT IN ADVANCE OF
THE AFOREMENTIONED RIDGE. A SURFACE FRONT STALLED JUST S/SE OF THE
AREA OVER CENTRAL/SOUTHERN SOUTH CAROLINA AT 15Z IS PROGGED TO
ASSUME A NW-SE ORIENTATION TODAY/TONIGHT...LIFTING NORTHWARD INTO
PORTIONS OF THE WESTERN NC PIEDMONT/FOOTHILLS AND EXTENDING
SOUTHEAST IN VICINITY OF CAPE FEAR/WILMINGTON.
TEMPERATURES:
CHALLENGING FORECAST. LINGERING LOW STRATUS (CEILINGS 500-1500 FT
AGL) WAS PRESENT ALONG AND SOUTH OF HIGHWAY 64 THIS MORNING...ASIDE
FROM A FEW LOCATIONS IN THE FAR SOUTHWEST PIEDMONT RIGHT NEAR THE SC
BORDER. 1000-850 MB THICKNESSES ARE PROGGED TO RANGE FROM 1375-1385
METERS IN THE COASTAL PLAIN (CLOSER TO THE STRENGTHENING SFC RIDGE)
TO ~1400 METERS IN THE W/SW PIEDMONT (CLOSER TO THE AFOREMENTIONED
FRONT). HIGHS TODAY AT ANY GIVEN LOCATION WILL DEPEND PRIMARILY ON
TWO FACTORS...PROXIMITY TO THE COOLER AIRMASS TO THE EAST...THE
WARMER AIRMASS TO THE WEST...AND WHEN LINGERING LOW-LEVEL CLOUD
COVER WILL ERODE ALONG/SOUTH OF HWY 64. WITH THE ABOVE IN MIND...
WILL FCST HIGHS RANGING FROM THE UPPER 60S IN THE COASTAL PLAIN TO
THE MID 70S/LOWER 80S IN THE WEST/SW PIEDMONT AND PORTIONS OF THE
SANDHILLS...WARMEST WHERE CLOUD COVER ERODES QUICKEST. AS THE
SFC-H85 RIDGE STRENGTHENS OVER EASTERN NC/VA TONIGHT...LOW-LEVEL
FLOW WILL VEER TO THE EAST/SE AND ADVECT A MOIST MARITIME AIRMASS
INTO CENTRAL NC. WIDESPREAD LOW CLOUD COVER IS EXPECTED TO ADVECT
INTO OR RE-DEVELOP OVER THE AREA...THICKER/LOWER WEST OF I-95 IN
CLOSER PROXIMITY TO BETTER LOW-LEVEL MOISTURE IN VICINITY OF THE
AFOREMENTIONED FRONTAL ZONE. EXPECT LOWS TO RANGE FROM THE MID/UPPER
50S EAST OF I-95 CENTRAL/NE COASTAL PLAIN TO THE UPPER 50S AND LOWER
60S ELSEWHERE...WARMEST SANDHILLS AND WEST/SW PIEDMONT.
PRECIP CHANCES TODAY:
A WEAK UPPER LEVEL DISTURBANCE WAS NOTED IN WV IMAGERY/RUC DATA IN
SOUTHWEST VA AT 15Z. THE LATEST RUC SHOWS THIS FEATURE PROGRESSING
SOUTHEAST VIA NW FLOW ALOFT THROUGH THE NORTHEAST COASTAL PLAIN BY
18-21Z AND OFFSHORE THE NC OBX BY 21-00Z. GIVEN UNFAVORABLE
THERMODYNAMICS IN ADVANCE OF THIS FEATURE IN THE COASTAL PLAIN
(CLOUDY/COOL/STABLE) THROUGH 18-21Z...EXPECT DRY CONDITIONS TO
PREVAIL EAST OF HWY 1 THIS AFT/EVE. MODERATE INSTABILITY IS EXPECTED
THIS AFTERNOON IN FAR WESTERN PORTIONS OF THE STATE...THOUGH MLCAPE
VALUES SHOULD REMAIN ON THE MARGINAL SIDE (500-1000 J/KG) IN THE
WESTERN PIEDMONT...CLOSER TO THE DRIER SFC RIDGE AXIS TO THE EAST.
DESTABILIZATION IN THE WEST WILL BE AIDED BY INCREASING BOUNDARY
LAYER MOISTURE (ASSOC/W THE FRONT PROGRESSING NORTHWARD INTO WESTERN
NC) IN THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) AND
CLEAR SKIES. HOWEVER...SUBSIDENCE IN THE WAKE OF THE AFOREMENTIONED
UPPER LEVEL DISTURBANCE ALONG WITH WEAK SYNOPTIC HEIGHT RISES IN
ADVANCE OF THE H5 RIDGE APPROACHING FROM THE WEST WILL BE
UNSUPPORTIVE OF PRECIP...AND LOW-LEVEL FORCING WILL BE CONFINED TO
BROAD WARM ADVECTION AND WEAK/SHALLOW LOW-LEVEL CONVERGENCE...WITH
THE RELATIVE BEST LOW-LEVEL FORCING CONFINED WEST OF I-77. IF ISOLD
CONVECTION DEVELOPS IN THE MOUNTAINS/FOOTHILLS AFTER 21Z...IT IS
CONCEIVABLE THAT IT COULD PROGRESS EAST/SE INTO PORTIONS OF THE NW
PIEDMONT BETWEEN 21-02Z THIS AFT/EVE VIA SPEEDY WESTERLY/WNW FLOW
ALOFT. THE LATEST 12Z WRF-NMM INDICATES THIS SCENARIO IS AT LEAST
POSSIBLE...AND WITH THAT IN MIND...WILL INTRODUCE A SLIGHT CHANCE OF
SHOWERS/STORMS TO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE.
IT IS INTERESTING THAT SUFFICIENT INSTABILITY AND 0-6 KM SHEAR MAY
BE PRESENT ON THE EASTERN PERIPHERY OF THE H5 RIDGE IN THE WESTERN
PIEDMONT TO SUPPORT A VERY LOW-END CONDITIONAL SEVERE THREAT LATER
THIS AFT/EVE...THOUGH A PROFOUND LACK OF FORCING AND THE PRESENCE OF
A DRY AIRMASS ALOFT (ASSOC/W AN EML EXTENDING EAST INTO THE AREA)
WILL MAKE IT DIFFICULT FOR ANY UPDRAFTS TO SURVIVE/PERSIST... SHOULD
ANY DEVELOP OR ADVECT INTO THE WESTERN PIEDMONT IN THE FIRST PLACE.
PRECIP CHANCES TONIGHT:
AS THE H5 RIDGE AXIS PROGRESSES EAST TO THE SPINE OF THE
APPALACHIANS TONIGHT...IT WILL BECOME INCREASINGLY DIFFICULT FOR ANY
UPSTREAM SHORTWAVES/MCVS (PROGRESSING EAST ATOP THE RIDGE) TO TRACK
INTO CENTRAL NC...WITH A MORE LIKELY TRACK FURTHER NORTH IN THE
MID-ATLANTIC. AS A RESULT...LITTLE OR NO UPPER SUPPORT WILL BE
PRESENT OVERNIGHT...THOUGH WEAK LOW-LEVEL WARM ADVECTION WILL BE
PRESENT. GIVEN THE CONTINUED PRESENCE OF AN ELEVATED MIXED LAYER
(ALBEIT MODIFIED)...EXPECT AT LEAST MARGINAL ELEVATED INSTABILITY TO
BE PRESENT OVERNIGHT. WITH THE ABOVE IN MIND...WILL CONTINUE TO
INDICATE A SLIGHT CHANCE OF SHOWERS OVERNIGHT IN ASSOC/W WARM
ADVECTION IN THE PRESENCE OF ELEVATED INSTABILITY. THUNDER CANNOT BE
RULED OUT...PRIMARILY IN THE WEST/NW PIEDMONT...THOUGH IT SEEMS
UNLIKELY IN THE ABSENCE OF ANY UPPER LEVEL SUPPORT. -VINCENT
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 230 AM SUNDAY...
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 301 PM SUNDAY...
...SUMMER-LIKE TEMPERATURES AND HUMIDITIES EXPECTED TUESDAY THROUGH
THE END OF THE WEEK...
AS WE BEGIN A NEW MONTH ON TUESDAY... IT WILL BE LIKE FLIPPING A
SWITCH FROM MILD TO HOT. THE OVERALL MID-UPPER LEVEL FLOW PATTERN IS
A HIGH CONFIDENCE FORECAST FOR THE REGION AS MODELS ARE IN EXCELLENT
AGREEMENT IN THE DEVELOPMENT OF A MODERATELY STRONG UPPER LEVEL
RIDGE OVER THE SOUTHEASTERN UNITED STATES TUESDAY AND WEDNESDAY.
THE UPPER RIDGE IS FORECAST TO PERSIST WELL INTO THE END OF THE
WEEK. THE UPPER RIDGE AXIS IS FORECAST TO PEAK OVER NC/SC BY
WEDNESDAY INTO THURSDAY... THEN SHIFT WESTWARD IN TIME FRIDAY INTO
SUNDAY. THE BOTTOM LINE... EXPECT A DRAMATIC SHIFT FROM MILD AND
MOIST CONDITIONS FROM THE PAST FEW WEEKS... TO SUMMERTIME CONDITIONS
TUESDAY THROUGH THE REST OF THE WEEK.
THERE ARE INDICATIONS THAT THE HOT/HUMID WEATHER WILL LAST 5-6
DAYS... THEN IT SHOULD BE FOLLOWED BY A SIGNIFICANT COOL DOWN LATE
NEXT WEEKEND OR AROUND MAY 6-9. (IF THE MODELS ARE CORRECT IN THE
LONGER TERM FORECAST SHIFT IN THE UPPER RIDGE WESTWARD BACK TO THE
PLAINS - ALLOWING THE CARVING OUT OF A H5 TROUGH ALONG THE EASTERN
SEABOARD).
THEREFORE THIS WEEK... EXPECT HOT AND UNSEASONABLY HUMID
CONDITIONS... WITH ONLY A SLIGHT CHANCE OF AN AFTERNOON OR EVENING
THUNDERSTORM BEYOND TUESDAY.
SENSIBLE WEATHER WILL START WITH CONDITIONS BECOMING VERY WARM AND
HUMID TUESDAY AS THE LEAD WARM FRONT LIFTS NORTH OF OUR REGION.
THERE IS A POTENTIAL FOR SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS AS MODELS INDICATE THE POTENTIAL FOR A VORTICITY
MAXIMUM TO RIDE A TOP THE BUILDING MID-UPPER LEVEL RIDGE OVER NC/VA
DURING MAXIMUM HEATING. FOR NOW... IT IS TOO EARLY TO LATCH ONTO
SUCH A FEATURE WITH ANY CONFIDENCE IN THE MODELS. HOWEVER... THIS
POTENTIAL WILL BE WATCHED. OTHERWISE... DIFFERENTIAL HEATING ALONG
THE EASTERN SLOPES OF THE MOUNTAINS SHOULD LEAD TO AT LEAST
SCATTERED THUNDERSTORMS TUESDAY AFTERNOON IN THE INCREASINGLY HUMID
BOUNDARY LAYER OVER NC/SW VA. SOME OF THESE MAY MOVE OFF OR DEVELOP
INTO THE PIEDMONT AS MODELS DO FAVOR A SURFACE TROUGH DEVELOPMENT IN
THE PIEDMONT DURING THE AFTERNOON. HIGHS WILL SOAR INTO THE MID TO
UPPER 80S. DEW POINTS SHOULD RISE TO BETWEEN 60-65... MAKING IT FEEL
LIKE JUNE OR EARLY JULY. WE WILL FORECAST 20-30 POP AND WAIT/SEE HOW
THE MODELS FORECAST ANY VORT MAX FOR TUESDAY TO AID IN CONVECTIVE
POTENTIAL.
AFTER THE SCATTERED CONVECTION POTENTIAL ENDS TUESDAY EVENING... WE
EXPECT THE MID-UPPER LEVEL RIDGING TO BE STRONG ENOUGH TO SUPPRESS
CONVECTIVE DEVELOPMENT IN THE ABSENCE OF ANY FOCUSING MECHANISMS
EVEN WITH DECENT LOW LEVEL MOISTURE AND HEAT. EXPECT GENERALLY WARM
DRY SUBSIDENCE IN THE MID LEVELS. WEDNESDAY THROUGH FRIDAY... MOSTLY
CLEAR MILD NIGHTS AND MOSTLY SUNNY HOT DAYS. DAILY TEMPERATURES
SHOULD AVERAGE A GOOD 10 DEGREES ABOVE NORMAL. NIGHTTIME LOWS A GOOD
10-15 DEGREES ABOVE NORMAL. LOWS SHOULD BE IN THE LOWER TO MID 60S
EACH DAY. HIGHS GENERALLY IN THE 85-90 RANGE.
SATURDAY AND SUNDAY... THE MID-UPPER HEIGHTS ARE FORECAST TO BEGIN
TO LOWER SOMEWHAT OVER THE SE WHICH SHOULD ALLOW DAILY TEMPERATURES
TO BACK OFF A FEW DEGREES. THE CHANCE OF CONVECTION SHOULD INCREASE
AT SOME POINT AS THE TROUGH DEVELOPS. HOWEVER... WE WILL KEEP ANY
MENTION OF SHOWERS OR THUNDERSTORMS ISOLATED... AND MAINLY LATE DAY
UNTIL A MORE DEFINITIVE TIMING OF AN ACTUAL COLD FRONT OR OTHER
FOCUS CAN BE PROJECTED. LOWS IN THE MID 60S. HIGHS IN THE LOWER TO
MID 80S.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 700 AM SUNDAY...
MVFR CEILINGS ARE PREDOMINATE ACROSS ALL OF CENTRAL NC THIS MORNING
AS LOW LEVEL MOISTURE REMAIN LOCKED IN PLACE NORTH OF STATIONARY
FRONT OVER SC. THE EXCEPTION IS OVER THE TRIAD WHERE DRIER AIR HAS
CAUSED THE LOW CLOUDS TO BREAK. MODELS INDICATE THE SHALLOW LAYER OF
LOW LEVEL MOISTURE WILL CONTINUE TO ERODE WITH SOUTH-SOUTHWESTERLY
LOW TO MID LEVEL FLOW TODAY. HOWEVER...MODELS MAY BE ERODING
STRATUS FROM THE SOUTH AND WEST TOO QUICKLY...AS THEY OFTEN DO....SO
MVFR CEILINGS MAY PERSIST WELL INTO THE AFTERNOON FROM KRDU TO
KRWI. WINDS WILL GENERALLY BE LIGHT AND VARIABLE FOR A GOOD PORTION
OF THE DAY BUT WILL BECOME EAST-NORTHEASTERLY AGAIN THIS EVENING AS
HIGH PRESSURE OVER THE GREAT LAKES PUSHES ANOTHER COLD FRONT INTO
THE AREA FROM THE NORTH. THIS COOL STABLE FLOW WILL BRING STRATUS
BACK ACROSS THE AREA ONCE AGAIN TONIGHT AND MONDAY
MORNING...POTENTIALLY WITH PATCHY LIGHT RAIN AT TIMES. -SMITH
OUTLOOK...
MVFR CEILINGS MAY PERSIST INTO THE DAY ON MONDAY...THOUGH AN OVERALL
DRYING TREND IS EXPECTED THROUGH MID WEEK AS AN UPPER LEVEL RIDGE
SETTLES OVER THE REGION. AFTERNOON SHOWERS/STORMS MAY BE POSSIBLE BY
WEDNESDAY BUT VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR MUCH OF THE
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...SMITH/99
LONG TERM...BADGETT
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
112 PM EDT SUN APR 29 2012
.SYNOPSIS...
A STALLED FRONT OVER SOUTH CAROLINA WILL RETURN NORTHWARD AS A WARM
FRONT OVER WESTERN PORTIONS OF THE STATE THIS AFTERNOON AND EVENING
AS HIGH PRESSURE STRENGTHENS AND PROGRESSES SOUTHWARD ALONG THE MID
ATLANTIC COAST.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 100 PM SUNDAY...
OVERVIEW:
AN H5 RIDGE CENTERED OVER THE WESTERN TN/OH VALLEYS AT 15Z WILL
PROGRESS EASTWARD TO THE SPINE OF THE APPALACHIANS BY 00-06Z
TONIGHT...RESULTING IN MODEST H5 HEIGHT RISES OVER THE MID-ATLANTIC
TODAY/TONIGHT. A SURFACE RIDGE AXIS EXTENDING SOUTH FROM THE
MID-ATLANTIC INTO THE CAROLINAS AT 15Z WILL WEAKEN IN WESTERN
PORTIONS OF THE STATE WHERE A WEAK TROUGH WILL DEVELOP. HOWEVER...
THE SURFACE RIDGE AXIS WILL STRENGTHEN TODAY/TONIGHT IN EASTERN
PORTIONS OF THE STATE IN ASSOC/W PRESSURE RISES ALONG THE MID-
ATLANTIC COAST...DUE TO HEIGHT RISES/SUBSIDENCE ALOFT IN ADVANCE OF
THE AFOREMENTIONED RIDGE. A SURFACE FRONT STALLED JUST S/SE OF THE
AREA OVER CENTRAL/SOUTHERN SOUTH CAROLINA AT 15Z IS PROGGED TO
ASSUME A NW-SE ORIENTATION TODAY/TONIGHT...LIFTING NORTHWARD INTO
PORTIONS OF THE WESTERN NC PIEDMONT/FOOTHILLS AND EXTENDING
SOUTHEAST IN VICINITY OF CAPE FEAR/WILMINGTON.
TEMPERATURES:
CHALLENGING FORECAST. LINGERING LOW STRATUS (CEILINGS 500-1500 FT
AGL) WAS PRESENT ALONG AND SOUTH OF HIGHWAY 64 THIS MORNING...ASIDE
FROM A FEW LOCATIONS IN THE FAR SOUTHWEST PIEDMONT RIGHT NEAR THE SC
BORDER. 1000-850 MB THICKNESSES ARE PROGGED TO RANGE FROM 1375-1385
METERS IN THE COASTAL PLAIN (CLOSER TO THE STRENGTHENING SFC RIDGE)
TO ~1400 METERS IN THE W/SW PIEDMONT (CLOSER TO THE AFOREMENTIONED
FRONT). HIGHS TODAY AT ANY GIVEN LOCATION WILL DEPEND PRIMARILY ON
TWO FACTORS...PROXIMITY TO THE COOLER AIRMASS TO THE EAST...THE
WARMER AIRMASS TO THE WEST...AND WHEN LINGERING LOW-LEVEL CLOUD
COVER WILL ERODE ALONG/SOUTH OF HWY 64. WITH THE ABOVE IN MIND...
WILL FCST HIGHS RANGING FROM THE UPPER 60S IN THE COASTAL PLAIN TO
THE MID 70S/LOWER 80S IN THE WEST/SW PIEDMONT AND PORTIONS OF THE
SANDHILLS...WARMEST WHERE CLOUD COVER ERODES QUICKEST. AS THE
SFC-H85 RIDGE STRENGTHENS OVER EASTERN NC/VA TONIGHT...LOW-LEVEL
FLOW WILL VEER TO THE EAST/SE AND ADVECT A MOIST MARITIME AIRMASS
INTO CENTRAL NC. WIDESPREAD LOW CLOUD COVER IS EXPECTED TO ADVECT
INTO OR RE-DEVELOP OVER THE AREA...THICKER/LOWER WEST OF I-95 IN
CLOSER PROXIMITY TO BETTER LOW-LEVEL MOISTURE IN VICINITY OF THE
AFOREMENTIONED FRONTAL ZONE. EXPECT LOWS TO RANGE FROM THE MID/UPPER
50S EAST OF I-95 CENTRAL/NE COASTAL PLAIN TO THE UPPER 50S AND LOWER
60S ELSEWHERE...WARMEST SANDHILLS AND WEST/SW PIEDMONT.
PRECIP CHANCES TODAY:
A WEAK UPPER LEVEL DISTURBANCE WAS NOTED IN WV IMAGERY/RUC DATA IN
SOUTHWEST VA AT 15Z. THE LATEST RUC SHOWS THIS FEATURE PROGRESSING
SOUTHEAST VIA NW FLOW ALOFT THROUGH THE NORTHEAST COASTAL PLAIN BY
18-21Z AND OFFSHORE THE NC OBX BY 21-00Z. GIVEN UNFAVORABLE
THERMODYNAMICS IN ADVANCE OF THIS FEATURE IN THE COASTAL PLAIN
(CLOUDY/COOL/STABLE) THROUGH 18-21Z...EXPECT DRY CONDITIONS TO
PREVAIL EAST OF HWY 1 THIS AFT/EVE. MODERATE INSTABILITY IS EXPECTED
THIS AFTERNOON IN FAR WESTERN PORTIONS OF THE STATE...THOUGH MLCAPE
VALUES SHOULD REMAIN ON THE MARGINAL SIDE (500-1000 J/KG) IN THE
WESTERN PIEDMONT...CLOSER TO THE DRIER SFC RIDGE AXIS TO THE EAST.
DESTABILIZATION IN THE WEST WILL BE AIDED BY INCREASING BOUNDARY
LAYER MOISTURE (ASSOC/W THE FRONT PROGRESSING NORTHWARD INTO WESTERN
NC) IN THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) AND
CLEAR SKIES. HOWEVER...SUBSIDENCE IN THE WAKE OF THE AFOREMENTIONED
UPPER LEVEL DISTURBANCE ALONG WITH WEAK SYNOPTIC HEIGHT RISES IN
ADVANCE OF THE H5 RIDGE APPROACHING FROM THE WEST WILL BE
UNSUPPORTIVE OF PRECIP...AND LOW-LEVEL FORCING WILL BE CONFINED TO
BROAD WARM ADVECTION AND WEAK/SHALLOW LOW-LEVEL CONVERGENCE...WITH
THE RELATIVE BEST LOW-LEVEL FORCING CONFINED WEST OF I-77. IF ISOLD
CONVECTION DEVELOPS IN THE MOUNTAINS/FOOTHILLS AFTER 21Z...IT IS
CONCEIVABLE THAT IT COULD PROGRESS EAST/SE INTO PORTIONS OF THE NW
PIEDMONT BETWEEN 21-02Z THIS AFT/EVE VIA SPEEDY WESTERLY/WNW FLOW
ALOFT. THE LATEST 12Z WRF-NMM INDICATES THIS SCENARIO IS AT LEAST
POSSIBLE...AND WITH THAT IN MIND...WILL INTRODUCE A SLIGHT CHANCE OF
SHOWERS/STORMS TO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE.
IT IS INTERESTING THAT SUFFICIENT INSTABILITY AND 0-6 KM SHEAR MAY
BE PRESENT ON THE EASTERN PERIPHERY OF THE H5 RIDGE IN THE WESTERN
PIEDMONT TO SUPPORT A VERY LOW-END CONDITIONAL SEVERE THREAT LATER
THIS AFT/EVE...THOUGH A PROFOUND LACK OF FORCING AND THE PRESENCE OF
A DRY AIRMASS ALOFT (ASSOC/W AN EML EXTENDING EAST INTO THE AREA)
WILL MAKE IT DIFFICULT FOR ANY UPDRAFTS TO SURVIVE/PERSIST... SHOULD
ANY DEVELOP OR ADVECT INTO THE WESTERN PIEDMONT IN THE FIRST PLACE.
PRECIP CHANCES TONIGHT:
AS THE H5 RIDGE AXIS PROGRESSES EAST TO THE SPINE OF THE
APPALACHIANS TONIGHT...IT WILL BECOME INCREASINGLY DIFFICULT FOR ANY
UPSTREAM SHORTWAVES/MCVS (PROGRESSING EAST ATOP THE RIDGE) TO TRACK
INTO CENTRAL NC...WITH A MORE LIKELY TRACK FURTHER NORTH IN THE
MID-ATLANTIC. AS A RESULT...LITTLE OR NO UPPER SUPPORT WILL BE
PRESENT OVERNIGHT...THOUGH WEAK LOW-LEVEL WARM ADVECTION WILL BE
PRESENT. GIVEN THE CONTINUED PRESENCE OF AN ELEVATED MIXED LAYER
(ALBEIT MODIFIED)...EXPECT AT LEAST MARGINAL ELEVATED INSTABILITY TO
BE PRESENT OVERNIGHT. WITH THE ABOVE IN MIND...WILL CONTINUE TO
INDICATE A SLIGHT CHANCE OF SHOWERS OVERNIGHT IN ASSOC/W WARM
ADVECTION IN THE PRESENCE OF ELEVATED INSTABILITY. THUNDER CANNOT BE
RULED OUT...PRIMARILY IN THE WEST/NW PIEDMONT...THOUGH IT SEEMS
UNLIKELY IN THE ABSENCE OF ANY UPPER LEVEL SUPPORT. -VINCENT
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM SUNDAY...
MONDAY IS AGAIN A STRUGGLE WITH HOW QUICKLY LOW CLOUDS WILL SCOUR AS
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND LOW LEVEL WINDS
BECOME SOUTH-SOUTHEASTERLY. WITH WESTERLY FLOW ALOFT....WARM
ADVECTION SHOWERS AND STORMS OVER THE HIGHER TERRAIN MAY BE ABLE
TO DRIFT EAST TOWARD THE WESTERN PIEDMONT...BUT COVERAGE SHOULD ONLY
BE ISOLATED. WE WILL CONTINUE TO LEAN TOWARD THE LOW SIDE OF
GUIDANCE FOR HIGHS...WITH LOW 70S NORTHEAST TO UPPER 70S SOUTHWEST.
LOWS MONDAY NIGHT AROUND 60.
HIGH PRESSURE SURFACE AND ALOFT LOCATED TO OUR SOUTH AT SUNRISE
TUESDAY. A SUBTLE SHORT WAVE IS SURPRISINGLY DEPICTED CONSISTENTLY
ACROSS SEVERAL MODELS FOR THE MID ATLANTIC REGION DURING THE DAY...
INDUCING WEAK SURFACE TROUGHING OVER VIRGINIA AND NORTH CAROLINA.
LOW LEVEL CONVERGENCE IS QUITE WEAK BUT AFTERNOON INSTABILITY...
CAPE AND MID LEVEL TEMPERATURE LAPSE RATES ALL INDICATE CONVECTION
IS A POSSIBILITY. WITH SUCH WEAK FORCING... WILL KEEP CHANCES FOR
THUNDER AT SLIGHT AND IN THE AFTERNOON.
MODEL CONSENSUS ON 1000 TO 850 MILLIBAR THICKNESS TUESDAY AFTERNOON
IN LINE WITH CLIMATOLOGICAL NORMALS FOR EARLY JUNE. CIRRUS CLOUDS
COULD IMPACT AFTERNOON TEMPERATURES... BUT FOR NOW WILL MINIMIZE
THIS AND FORECAST HIGH TEMPERATURES IN THE LOWER 80S NORTHWEST AND
MID 80S ELSEWHERE.
ANY AFTERNOON CONVECTION SHOULD NOT PERSIST PAST LATE EVENING
TUESDAY NIGHT. LOW LEVEL THICKNESSES MORE TYPICAL OF EARLY JUNE
PERSIST. PRECIPITABLE WATERS IN EXCESS OF 1.25 INCHES AND A LIGHT
SOUTHWEST BREEZE WITH PERIODS OF CALM WILL ALLOW TEMPERATURES TO
FALL NO LOWER THAN THE LOWER 60S BY SUNRISE WEDNESDAY.
LOW LEVEL THICKNESSES RISE FIVE TO TEN METERS WEDNESDAY AFTERNOON
OVER THE PREVIOUS DAY AND MIXING HEIGHTS WILL PERHAPS REACH 7000
FEET. MOISTURE IS SOMEWHAT LIMITED... ESPECIALLY TO THE SOUTH. A
WEAK BOUNDARY LOCATED NEAR OR NORTH OF HIGHWAY 64 WILL POTENTIALLY
BE A FOCUS FOR CONVECTION. DUE TO LIMITED MOISTURE WILL KEEP CHANCES
AT SLIGHT FOR MID TO LATE AFTERNOON. DAMAGING DOWNBURST WINDS WILL
BE A RISK DUE TO EVAPORATIVELY COOLED DOWNDRAFTS IF THE ABOVE
SCENARIO HOLDS UP... BUT WITH COVERAGE LIMITED TO ABSENT... NO PLANS
TO MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. AFTERNOON
THICKNESSES MORE TYPICAL OF MID JULY ARE FORECAST. HIGH TEMPERATURES
MOSTLY MID 80S.
IN SPITE OF THE BOUNDARY IN THE NORTH... ANY CONVECTION LOOKS TO BE
SHORT LIVED ONCE THE HEATING OF THE DAY IS LOST. LOW TEMPERATURES
SHOULD FALL NO LOWER THAN THE LOW TO MID 60S AS 1000 TO 850 MILLIBAR
THICKNESSES REMAIN ABOVE 1400 METERS.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 AM SUNDAY...
THE AIR MASS DRYS A BIT THURSDAY IN LIGHT WEST FLOW AS THE UPPER
LEVEL RIDGE OVER THE EASTERN UNITED STATES STRENGTHENS SLIGHTLY.
LATE AFTERNOON CONVECTION NOT IMPOSSIBLE BUT CHANCES LOOK LESS THAN
SLIGHT AT THIS TIME... WITH THE SCENARIO REPEATING FOR FRIDAY AS
WELL. CONTINUE TO FAVOR THE MORE PERSISTENT RIDGE OF THE ECMWF MODEL
THOUGH THE ECMWF DOES RETROGRADE THE RIDGE TO THE MIDWEST THURSDAY
NIGHT AND INTO THE WEEKEND. THIS SHOULD ALLOW AFTERNOON TEMPERATURES
TO SLIP A BIT SATURDAY AND INCREASE AFTERNOON RAIN CHANCES FOR
SATURDAY AFTERNOON.
WELL ABOVE NORMAL TEMPERATURES TO CONTINUE FOR THIS FORECAST PERIOD.
MID TO UPPER 80S THURSDAY AND FRIDAY... LOW TO MID 80S SATURDAY. LOW
TEMPERATURES IN THE LOW TO MID 60S.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 700 AM SUNDAY...
MVFR CEILINGS ARE PREDOMINATE ACROSS ALL OF CENTRAL NC THIS MORNING
AS LOW LEVEL MOISTURE REMAIN LOCKED IN PLACE NORTH OF STATIONARY
FRONT OVER SC. THE EXCEPTION IS OVER THE TRIAD WHERE DRIER AIR HAS
CAUSED THE LOW CLOUDS TO BREAK. MODELS INDICATE THE SHALLOW LAYER OF
LOW LEVEL MOISTURE WILL CONTINUE TO ERODE WITH SOUTH-SOUTHWESTERLY
LOW TO MID LEVEL FLOW TODAY. HOWEVER...MODELS MAY BE ERODING
STRATUS FROM THE SOUTH AND WEST TOO QUICKLY...AS THEY OFTEN DO....SO
MVFR CEILINGS MAY PERSIST WELL INTO THE AFTERNOON FROM KRDU TO
KRWI. WINDS WILL GENERALLY BE LIGHT AND VARIABLE FOR A GOOD PORTION
OF THE DAY BUT WILL BECOME EAST-NORTHEASTERLY AGAIN THIS EVENING AS
HIGH PRESSURE OVER THE GREAT LAKES PUSHES ANOTHER COLD FRONT INTO
THE AREA FROM THE NORTH. THIS COOL STABLE FLOW WILL BRING STRATUS
BACK ACROSS THE AREA ONCE AGAIN TONIGHT AND MONDAY
MORNING...POTENTIALLY WITH PATCHY LIGHT RAIN AT TIMES. -SMITH
OUTLOOK...
MVFR CEILINGS MAY PERSIST INTO THE DAY ON MONDAY...THOUGH AN OVERALL
DRYING TREND IS EXPECTED THROUGH MID WEEK AS AN UPPER LEVEL RIDGE
SETTLES OVER THE REGION. AFTERNOON SHOWERS/STORMS MAY BE POSSIBLE BY
WEDNESDAY BUT VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR MUCH OF THE
WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...SMITH/99
LONG TERM...99
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1256 PM EDT SUN APR 29 2012
.SYNOPSIS...
A NEARLY STATIONARY FRONT ACROSS THE AREA WILL GRADUALLY PUSH
SOUTHWARD BY LATE TONIGHT. BERMUDA HIGH PRESSURE WILL DEVELOP
TUESDAY...BRINGING A MORE SUMMER-LIKE PATTERN AND A WARMING TREND
THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM SUNDAY...THE FRONT IS SAGGING SOUTH ACROSS THE CAROLINA
COASTAL WATERS EARLY THIS AFTERNOON...EASILY VISIBLE ON SATELLITE
IMAGERY AS A ROPE CLOUD WRAPPING AROUND THE TIP OF CAPE FEAR. ALMOST
ALL MODELS HAVE CONTINUED TO STRUGGLE WITH THE BEHAVIOR OF THIS
FRONT OVER THE PAST 24-36 HOURS. THE MOST RELIABLE MODELS AS OF THIS
MOMENT APPEAR TO BE THE 12Z RUC AND THE 00Z WRF-NMM. LOW STRATUS
CONTINUES TO FRAGMENT INLAND AS STRONG LATE APRIL SUNSHINE WORKS ON
WARMING THE BOUNDARY LAYER AND STEEPENING LAPSE RATES UP THROUGH THE
CLOUD BASES. SUNNY SKIES FROM FLORENCE AND CONWAY SOUTH WILL ALLOW
TEMPERATURES TO SOAR INTO THE MID TO UPPER 80S TODAY...WHILE TO THE
NORTH A COOLER AND SOMEWHAT CLOUDIER AIRMASS WILL HOLD TEMPERATURES
IN THE MID TO UPPER 70S. THE COOLEST READINGS WILL EXIST ALONG THE
BEACHES NORTH OF CAPE FEAR WHERE TEMPERATURES WILL DO GOOD TO EXCEED
70 DEGREES FOR AN HOUR OR TWO BATTLING THE COOL SEABREEZE. A
SUBSTANTIAL SUBSIDENCE INVERSION BETWEEN 700-800 MB WILL CAP OFF ANY
GROWING CUMULUS WITHIN THE WARMER MORE DEEPLY-MIXED AIRMASS SOUTH OF
THE FRONT.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...TRICKY START TO THE FORECAST PERIOD AS A BACK
DOOR COLD FRONT AND ITS ASSOCIATED BAROCLINIC GRADIENT SHIFT SOUTH
TOWARDS...OR OVER...THE ILM CWA. GUIDANCE CONTINUES TO BACK OFF ON
STRENGTH AND LATITUDINAL PROGRESS OF THIS FRONT...WHICH MAKES SENSE
BASED OFF THE FACT IT IS NEARLY MAY. HOWEVER...EXACT SOUTHERN
DISPLACEMENT OF THIS FRONT WILL MAKE A LARGE DIFFERENCE IN MAX TEMPS
AND CLOUD COVER MONDAY.
GFS/ECMWF IN DECENT AGREEMENT...AND ARE MORE AGGRESSIVE THAN NAM IN
TURNING WINDS E/NE DURING MONDAY WITH A COOL SURGE BEHIND THE FRONT.
WILL FAVOR THIS SOLUTION WHICH SHOWS A SUBTLE DECREASE IN WEDGE
STRENGTH FROM PREVIOUS GUIDANCE...VS THE NAM WHICH IS MUCH WEAKER
WITH FROPA. THIS CREATES A BELOW CLIMO AND MOSTLY CLOUDY DAY AS
MOISTURE IN THE 1000-800MB LAYER GETS TRAPPED BELOW BUILDING UPPER
RIDGING. PRECIP CHANCES LOOK VERY MARGINAL WITH SOME WEAK ISENTROPIC
LIFT ACROSS NORTHERN ZONES...AND WILL KEEP POP SILENT SINCE ANY
RAINFALL MAY NOT EVEN MEASURE A TRACE DURING MONDAY. AS MENTIONED
PREVIOUSLY...TEMPS WILL BE QUITE TRICKY AND HIGHLY DEPENDENT ON
EXACT FRONTAL PLACEMENT...BUT WILL INDICATE MID 70S IN THE FAR
NE...TO AROUND 80 FAR SW. OF COURSE...THESE COULD VARY HIGHLY IF
FRONT DOES NOT BEHAVE AS CURRENTLY ANTICIPATED.
BY LATE MONDAY HIGH PRESSURE DRIFTS OFF THE MID-ATLANTIC AND
SOUTHERLY RETURN FLOW PUSHES THE REMNANT FRONT BACK TO THE NORTH.
WARM AND MOIST AIR FLOODS BACK INTO THE REGION KEEPING MINS MONDAY
NIGHT WELL ABOVE CLIMO...ONLY IN THE LOW 60S.
A MUCH BETTER DAY ON TUESDAY AS HIGH PRESSURE SITS OFFSHORE ALLOWING
FOR A CONTINUATION OF WAA ON SOUTHERLY FLOW. COMBINING THIS WITH
BUILDING HEIGHTS ALOFT MAKES TUESDAY A SLIGHTLY ABOVE CLIMO
DAY...LOW TO MID 80S...UNDER ONLY PARTLY CLOUDY SKY CONDITIONS. MINS
AT NIGHT WILL ONCE AGAIN BE WELL ABOVE CLIMO.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 3 AM SUNDAY...QUIET AND ABOVE NORMAL EARLY-MAY WEATHER
ANTICIPATED INTO THE WEEKEND. LARGE UPPER RIDGE DEVELOPS ACROSS THE
SOUTHEAST AND REMAINS IN PLACE THROUGH AT LEAST FRIDAY. WITH A
SURFACE HIGH ANCHORED OFFSHORE...SURFACE WARM AIR AND A MID LEVEL
CAP WILL CREATE MOSTLY SUNNY AND WARM CONDITIONS THROUGH THE
WEEK...WITH TEMPS WELL INTO THE 80S AWAY FROM THE IMMEDIATE COAST.
THE FAVORED HOT SPOTS MAY APPROACH 90 WED/THU/FRI AS 850MB TEMPS
SOAR TO +17C AND SOME DOWNSLOPE COMPRESSIONAL WARMING AID IN WARMING
THE SURFACE.
FORECAST CONFIDENCE DECREASES FOR SATURDAY AS CENTRAL RIDGING
STRENGTHENS FORMING AN OMEGA TYPE BLOCK ACROSS THE MIDDLE OF THE
COUNTRY. AT THE SAME TIME...ECMWF/GFS SHOW A VORT/UPPER TROUGH
DEVELOPING ON THE SE OF THIS RIDGE ACROSS THE GOM...WHILE A
NORTHERN STREAM S/W TROUGH DROPS OUT OF CANADA ALONG ITS EASTERN
PERIPHERY. THESE FEATURES COULD WORK IN TANDEM TO BREAK DOWN THE
RIDGING FROM THE EAST AND PUSH A COLD FRONT THROUGH THE AREA.
FREQUENTLY GUIDANCE IS TOO FAST IN BREAKING DOWN SUBTROPICAL RIDGES
SO WILL FOR NOW KEEP THE EXTENDED DRY. HOWEVER...MUST NOTE THAT A
DECREASE IN MID LEVEL CAPPING AND INCREASE IN MOISTURE COULD CREATE
DIURNAL CONVECTION FRIDAY...WITH A BETTER CHANCE SATURDAY IF THE
COLD FRONT DOES REACH THIS AREA.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...LINGERING MVFR AT KILM/KLBT WILL GRADUALLY IMPROVE OVER
THE NEXT HOUR OR SO AS STRATUS FROM THIS MORNING CONTINUES TO BURN
OFF. A NEARLY-STATIONARY FRONT EXTENDS FROM APPX 20 S ILM TO 20 N
CRE TO 25 S LBT. ANTICIPATE CONDITIONS TO BECOME VFR AREA-WIDE THIS
AFTERNOON WITH SCT LOW TO MID LEVEL CLOUDS THROUGH THE EVENING
HOURS...POSSIBLY BECOMING BKN AT TIMES. CURRENT TIME-HEIGHT ANALYSIS
DEPICTS MOIST LOW-LEVELS OVERNIGHT INTO THE MORNING HOURS MONDAY. WE
HAVE BROUGHT MVFR/IFR BACK INTO THE FORECAST LATE TONIGHT DUE TO LOW
STRATUS WITH POTENTIAL FOG DEVELOPMENT (3SM) AT A FEW SITES...AND
POSSIBLY LOWER. THE SEA BREEZE WILL ALLOW WINDS ALONG THE COAST AND
FARTHER INLAND TO BECOME SOUTHEAST LATER THIS AFTERNOON WITH
SUSTAINED WINDS LESS THAN 12KTS.
EXTENDED OUTLOOK...A SLIGHT CHANCE OF MVFR/SHOWERS THROUGH TUESDAY.
LOW CONFIDENCE IFR VSBYS IN MORNING FOG TUESDAY AND WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM SATURDAY...VISIBLE SATELLITE IMAGERY SHOWS THE COLD FRONT
DROPPING SOUTH PAST BALD HEAD ISLAND EARLY THIS AFTERNOON...WITH
NORTHEAST 10-15 KT WINDS FOLLOWING BEHIND TO THE NORTH. SOUTH OF THE
FRONT A VERY LIGHT WEST WIND SHOULD TURN FIRMLY ONSHORE WITHIN THE
NEXT HOUR OR TWO DUE TO A DEVELOPING SEABREEZE CIRCULATION. OTHER
THAN THE VARYING WIND DIRECTIONS IN THE VICINITY OF THE FRONT NO
SIGNIFICANT WEATHER IS EXPECTED THIS AFTERNOON. SEAS RANGE FROM 1 TO
2 FT WEST OF CAPE FEAR...AND AROUND 2 FT EAST OF CAPE FEAR...WITH
DOMINANT PERIODS 6-7 SECONDS.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...BACK DOOR COLD FRONT DROPS SOUTH ACROSS AT
LEAST THE NORTHERN WATERS MONDAY...BUT MAY NOT MAKE IT ALL THE WAY
SOUTH THROUGH AMZ256 DURING THE DAY. ALTHOUGH A DECENT NE SURGE IS
LIKELY ACROSS THE NC WATERS DURING MONDAY...WITH E/NE WINDS
INCREASING TO 10-15 KTS...THE SOUTHERN WATERS WILL SEE WINDS ONLY
AROUND 10 KTS...MORE FROM THE EAST THAN NE. WAVE HEIGHTS WILL BE
PREDOMINATELY WIND DRIVEN...WITH A 2-3 FT NE WIND CHOP ACROSS THE NC
WATERS...AND 2-3 FT CONFUSED SEAS IN THE SOUTH. BY LATE
MONDAY...FRONT RETURNS TO THE NORTH AS HIGH PRESSURE PUSHES OFFSHORE
THE MID ATLANTIC. THIS TURNS WINDS TO THE SE...THEN SOUTH ON TUESDAY
AT AROUND 10 KTS. SEAS BUILD TO 3-4 FT THROUGH THE END OF THE
PERIOD...WITH A WEAK SOUTH WIND WAVE OVER TOPPING AN INCREASING 8
SECOND SE SWELL.
LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...RATHER UNIFORM WIND/WAVE CONDITIONS WILL
CONTROL THE EXTENDED AS HIGH PRESSURE OFFSHORE CREATES S/SW RETURN
FLOW ACROSS THE WATERS. OTHER THAN SLIGHT DIURNAL CHANGES EACH
DAY...SW WINDS AROUND 10 KTS PERSIST THROUGH THURSDAY. THE ONLY
NOTICEABLE DIFFERENCE THROUGH THE EXTENDED WILL BE AN INCREASING SE
SWELL DUE TO ELONGATED EASTERLY FETCH AROUND THE SOUTH SIDE OF
BERMUDA HIGH PRESSURE. SEAS OF 2-4 FT PERSIST THROUGH THE
EXTENDED...AND EVEN THOUGH A LIGHT WIND CHOP WILL BE EVIDENT...THE
SWELL WILL DOMINATE THE WAVE SPECTRUM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
349 PM EDT SUN APR 29 2012
.SYNOPSIS...
RIDGE OVER THE EASTERN LAKES WILL MOVE EAST TONIGHT. A WARM FRONT
OVER THE OHIO VALLEY WILL BEGIN TO MOVE NORTH ON MONDAY. THE FRONT
WILL MOVE BACK SOUTH AS A COLD FRONT MONDAY NIGHT AND THEN PUSH NORTH
OF THE AREA BY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE ISSUES TONIGHT ARE HOW QUICKLY WILL THE CLOUDS AND PRECIPITATION
GET INTO THE FORECAST AREA. THE CLOUDS WILL SLOWLY INCREASE FROM
WEST. THE AIR IS DRY...SOME THE SHOWERS MAY NOT MAKE IT INTO
NORTHWEST OHIO AS QUICKLY AS THE HRRR MODELS THINKS. WILL SLOW IT
DOWN SOME SEVERAL HOURS. A LOT OF THE GUIDANCE IS TENDING TOWARD
STABLE...SO NO THUNDER THROUGH DAYBREAK.
BECAUSE OF THE INCREASE IN CLOUDS AND SOME WIND...DO NOT EXPECT
TEMPERATURES BELOW FREEZING IN NORTHWEST PA AND PROBABLY NO
SUBSTANTIAL FROST TO SPEAK OF...MENTIONED PATCHY FROST IN OUTLYING
AREAS EAST OF MEADVILLE AND ERIE FOR A FEW HOURS.
WENT TOWARD THE WARMER GUIDANCE FOR THE LOWS...ESPECIALLY NORTHWEST
OHIO.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
ON THE EDGE ABOUT THE POPS FOR MONDAY. THE WARM FRONT WILL MOVE INTO
NORTHERN OHIO AND THEN PART OF THE AREA WILL GET INTO THE WARM
SECTOR MONDAY AFTERNOON AND THEN AS THE LOW MOVES ALONG THE FRONT
THE COLD FRONT WILL MOVE BACK SOUTH OF THE REGION FOR A TIME. WENT
MORE TOWARD THE GFS. WANTED TO GO WITH OCCASIONAL POPS FOR
MONDAY...BUT WITH SOME QUESTION ABOUT THE TIMING DIDN`T DO THAT.
IT SHOULD NOT RAIN ALL DAY...SHOULD BE SOME DRY PERIODS. ON THE
EDGE ABOUT THE RISK OF SEVERE THUNDERSTORMS...IT COULD BE CLOSE IN
THE SOUTHERN COUNTIES. THE HWO HAS SOME MENTION OF STRONG TO
SEVERE STORMS.
THE FORECAST FOR TUESDAY THROUGH WEDNESDAY NIGHT IS JUST FOR A
CHANCE OF SHOWERS AND THUNDERSTORMS WITH QUESTIONS ABOUT THE TIMING
AND THE MOISTURE.
RAINFALL SHOULD BE UNDER AN INCH WITH ISOLATED HIGHER AMOUNTS IN
THUNDERSTORMS. WITH THE GROUND SATURATED IT SHOULD NOT BE A BIG PROBLEM.
FORECAST LOWS AND HIGHS ARE TOUGH...USED A BLEND OF
GUIDANCE. TENDED TOWARD THE WARMER GUIDANCE...MONDAY IS REALLY
TOUGH WITH THE THREAT OF SHOWERS AND THUNDERSTORMS JUST ABOUT
ANYTIME.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
LONG TERM PORTION BEGINS ON FRIDAY WITH MODELS IN GENERAL AGREEMENT
SHOWING ZONAL FLOW ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION.
AT THE SURFACE...HIGH PRESSURE WILL BE ACROSS THE SOUTHEASTERN
STATES WITH A COLD FRONT NE TO SW ACROSS THE GREAT LAKES. MODELS
SHOW ENOUGH MOISTURE FOR CLOUDS AND PRECIP HOWEVER THE REGION WILL
BE IN THE WARM SECTOR SO WILL PUT ENOUGH FOR PARTLY CLOUDY/PARTLY
SUNNY AND EXPECT JUST SCATTERED/CHANCE POPS. SATURDAY SHOULD START
OUT MUCH THE SAME ALTHOUGH THE COLD FRONT SHOULD TRACK SOUTH ACROSS
THE AREA DURING THE EVENING OR OVERNIGHT SATURDAY NIGHT BUT LIMITED
MOISTURE BY THAT TIME ON THE ECMWF SO WILL GO WITH A DRY PASSAGE FOR
NOW. SUNDAY WILL REMAIN DRY AS UPPER HIGH BUILDS IN FROM THE WEST.
&&
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
HIGH PRESSURE AND VERY DRY AIR IN PLACE ACROSS THE AREA TODAY.
WARM FRONT TO THE SOUTHWEST WILL APPROACH THE AREA FROM THE
SOUTHWEST OVERNIGHT. OVERRUNNING MOISTURE WILL MOVE IN MAINLY
OVERNIGHT WITH LOWERING CEILINGS EXPECT LIGHT RAIN TO MOVE INTO
THE TOL-FDY-MFD AREAS FROM 08-09Z AND CLE AROUND 12Z. CONDITIONS
WILL LIKELY DROP TO MVFR IN THE RAIN. MODELS ALSO SHOWING
INSTABILITY MOVING IN SO COULD HAVE THUNDERSTORMS IN THE AREA
MONDAY AFTERNOON. WILL HAVE VCTS IN CLE FOR THE
AFTERNOON...OTHERWISE WILL NOT HAVE THUNDER IN THE FORECAST THIS
PACKAGE.
.OUTLOOK...NON-VFR CONDITIONS POSSIBLE ALONG A WARM FRONT MONDAY
NIGHT THROUGH TUESDAY NIGHT.
&&
.MARINE...
HIGH PRESSURE OVER THE LAKES WILL MOVE EAST OVERNIGHT AND ALLOW WEAK
LOW PRESSURE TO MOVE THROUGH THE OHIO VALLEY MONDAY AND ACROSS LAKE
ERIE MONDAY NIGHT. THIS WILL BRING A WARM FRONT ONTO THE LAKE
MONDAY NIGHT...FOLLOWED QUICKLY BY A COLD FRONT. TUESDAY HIGH
PRESSURE WILL BUILD ACROSS THE LAKE. WEDNESDAY THE HIGH WILL MOVE
EAST AND WITH LOW PRESSURE ACROSS THE CENTRAL AND NORTHERN PLAINS A
SOUTHERLY GRADIENT OF MILD AIR WILL MOVE ACROSS THE LAKE AND
CONTINUE THROUGH THE FRIDAY. WINDS WILL REMAIN GENERALLY LIGHT AT
15 KNOTS OR LESS MOST OF THE TIME. WAVES WILL REMAIN BELOW 4 FEET SO
EXPECT NO HEADLINES NEXT SEVERAL DAYS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...TK
AVIATION...TK
MARINE...TK