Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/28/12
AREA FORECAST DISCUSSION
NWS TUCSON AZ
905 PM MST WED APR 25 2012
.SYNOPSIS...A STRONG LOW PRESSURE SYSTEM ON THURSDAY WILL BRING
GUSTY WINDS...MUCH COOLER TEMPERATURES...AND A FEW SHOWERS TO THE
AREA. DRY CONDITIONS WITH A WARMING TREND WILL START FRIDAY AND
CONTINUE INTO EARLY NEXT WEEK.
&&
.DISCUSSION...UPPER LOW APPROACHING THE SRN CALIFORNIA COAST WITH
ABUNDANT MID AND HIGH-LEVEL CLOUDS MOVING NEWD ACROSS SE AZ AT THIS
TIME. LIGHTNING STRIKES HAVE BEEN DETECTED THIS EVENING ASSOCIATED
JUST AHEAD OF THE UPPER LOW PRESSURE SYSTEM. 26/00Z NAM DEPICTS
PRECIP-FREE CONDITIONS ACROSS SE AZ THRU 26/09Z...THEN A FEW
HUNDREDTHS OF AN INCH DEVELOPS SOUTH OF TUCSON ACROSS SANTA CRUZ
COUNTY AS WELL AS ACROSS WRN PIMA COUNTY AROUND SUNRISE THUR.
THEREAFTER...NAM AND RUC HRRR WERE SIMILAR WITH KEEPING MEASURABLE
PRECIP NORTH OF TUCSON ON THUR. HAVE NOTED THAT THE SUSTAINED WINDS
FOR KDUG VIA THE NAM MOS GUIDANCE PRODUCT WOULD ACHIEVE WIND
ADVISORY CRITERIA THUR AFTERNOON. NO UPDATES PLANNED AT THIS TIME.
PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION FOR ADDITIONAL
DETAIL.
&&
.PREV DISCUSSION...MODELS INDICATE THAT THE UPPER LOW WILL MOVE VERY
CLOSE TO THE EXTREME SOUTHERN CALIFORNIA COAST BY AROUND MIDNIGHT
TONIGHT...THEN ACROSS SOUTHWEST ARIZONA BY MIDDAY THURSDAY. THE
MODELS SUGGEST THAT PRECIPITABLE WATER VALUES WILL INCREASE WITH A
THIN BAND OF 1 INCH PW AMOUNTS MAINLY TO THE WEST OF TUCSON OVER THE
FAR WESTERN DESERTS OF PIMA COUNTY AND INTO WESTERN MARICOPA COUNTY
BETWEEN 12 AND 18Z. DURING THE AFTERNOON HOURS THE PW`S DROP OFF
WELL BELOW THREE QUARTERS OF AN INCH. MOS POP NUMBERS WITH THIS
SYSTEM ARE EXTREMELY LOW...AT LEAST THIS FAR SOUTH. THE 12Z NAM MOS
POP FOR TUCSON IS ONLY SHOWING 3 PERCENT FOR THURSDAY AND THE GFS
ONLY 23 PERCENT. MOS NUMBERS ARE HIGHER TO THE NORTH TOWARD THE
PHOENIX AREA...BUT THIS FAR SOUTH THE THREAT FOR PRECIP SHOULD BE
FAIRLY LOW. THAT SAID...I ONLY MADE SOME MINOR CHANGES TO THE POPS
AND KEPT THE TREND OF LOWERING POPS THAT THE MIDNIGHT SHIFT STARTED
LAST NIGHT. BASICALLY THIS MEANS A FAIRLY STEEP POP GRADIENT WILL
EXIST ACROSS MY FORECAST AREA FROM SOUTH TO NORTH WITH HIGHER POPS
OVER THE CENTRAL AND NORTHERN PORTIONS OF THE STATE.
THE SYSTEM QUICKLY EXITS THE REGION TO THE NORTHEAST LATE THURSDAY.
NORTHWEST TO NEARLY ZONAL FLOW ALOFT WILL RESIDE ACROSS THE DESERT
SOUTHWEST THROUGH SATURDAY AS WEAK DISTURBANCES MOVE THROUGH THE
FLOW TO OUR NORTH. BY LATE THIS WEEKEND AND EARLY NEXT WEEK A BAGGY
TROUGH DEVELOPS ACROSS THE WEST AND THEN THE MODELS BEGIN TO DIVERGE
IN THEIR SOLUTIONS BY MONDAY. AT ANY RATE IT LOOKS LIKE A DRY
FORECAST THROUGH NEXT WEDNESDAY.
HIGHS WILL GENERALLY BE 2 TO 5 DEGS BELOW NORMAL THURSDAY AND
FRIDAY...THEN 2 TO 4 DEGS ABOVE NORMAL FOR SATURDAY. THEREAFTER...
HIGHS WILL BE 5 TO 7 DEGS ABOVE NORMAL. LOWS WILL BE 10 TO 12 DEGS
ABOVE NORMAL TONIGHT/EARLY THURSDAY...THEN SLIGHTLY BELOW NORMAL
FRIDAY. A WARMING TREND WILL BEGIN ON SATURDAY AND LOWS WILL BE
AROUND 3 TO 6 DEGS ABOVE NORMAL SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...SCT-BKN CLOUDS MOSTLY ABOVE 15K FT AGL THE REST OF
TONIGHT THEN CLOUD DECKS LOWERING TO 5-10K FT AGL AROUND DAYBREAK
THURSDAY AND CONTINUING THRU THURSDAY AFTERNOON. ISOLD-SCT -SHRA AND
A SLIGHT CHANCE OF -TSRA MAINLY NORTH OF KTUS THURSDAY. DECREASING
CLOUDINESS THURSDAY AFTERNOON THEN SKC BY FRIDAY MORNING. SURFACE
WIND GENERALLY LESS THAN 10 KTS THRU EARLY THURSDAY MORNING...THEN
SURFACE WIND WLY/SWLY 15-25 KTS WITH GUSTS TO 40 KTS THURSDAY
AFTERNOON. SURFACE WIND GENERALLY LESS THAN 10 KTS THURSDAY NIGHT.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...STRONGER WINDS ARE EXPECTED ON THURSDAY AS A STORM
SYSTEM MOVES ACROSS THE STATE. THIS SYSTEM WILL RESULT IN MUCH
COOLER TEMPERATURES...A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS THURSDAY. A RAPID WARMING TREND WILL THEN OCCUR BEHIND
THE SYSTEM FRIDAY AND SATURDAY.
WITH THE STRONGER WINDS ON THURSDAY...FAR EASTERN AREAS WHERE THE
MOISTURE MOVES IN LAST...MAY BRIEFLY APPROACH CRITICAL FIRE WEATHER
THRESHOLDS THURSDAY AFTERNOON. THE AREA OF STRONGER WINDS AND LOW
RELATIVE HUMIDITIES IS NOT EXPECTED TO BE WIDESPREAD EITHER...
CONFINED MAINLY TO NEW MEXICO BORDER...OR EAST OF A DOUGLAS TO
WILLCOX TO SAFFORD LINE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER CO
950 PM MDT FRI APR 27 2012
.UPDATE...
&&
.SHORT TERM...NORTHWEST WINDS OVER THE NORTHEAST PLAINS HAVE
BECOME MORE NORTHERLY...ALLOWING AN ANTICYCLONIC SWIRL INTO
DENVER. A LARGER SCALE TURNING HAS PUSHED MOISTURE BACK INTO THE
SOUTHEAST AND SET UP AN AREA OF CONVERGENCE FROM INTERSTATE 70 ON
THE PLAINS INTO THE CENTRAL MOUNTAINS. SHOWERS HAVE BEEN FIRING ON
THIS BOUNDARY INTERMITTENTLY AND WITH DEVELOPMENT CONTINUING AND
SOME CLOUDS EVEN DEVELOPING BACK OVER THE MOUNTAINS I WILL HAVE TO
ADD THEM BACK INTO THE FORECAST. INSTABILITY AND CONVERGENCE
SHOULD BE WEAKENING LATER TONIGHT...SO WE STILL THINK THIS WILL BE
MAINLY BEFORE MIDNIGHT.
&&
.AVIATION...NORTHEAST WINDS AT KDEN/KAPA WILL DIMINISH WITH THE
DIRECTION BECOMING MORE SELY OVER THE NEXT COUPLE OF HOURS. AT
KBJC MORE UNCERTAINTY ABOUT THE WIND DIRECTION...IT SHOULD BECOME
LIGHTER...PROBABLY NORTHEAST INITIALLY BUT MAY BECOME SOUTHERLY
LATER TONIGHT BEFORE TURNING BACK TO THE WEST. REMAINDER OF THE
FORECAST UNCHANGED WITH VFR CONDITIONS AND LIGHT DIURNAL WINDS ON
SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 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/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS PUEBLO CO
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. STARK
&&
.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.
&&
$$
31/40
AREA FORECAST DISCUSSION
NWS DENVER CO
1005 AM MDT THU APR 26 2012
.UPDATE...FIRST WAVE EXITING NORTHEAST COLORADO WITH SCATTERED
CONVECTION OVER THE NORTHEASET CORNER. NEXT WAVE SHOWING UP IN
NORTHWEST ARIZONA WITH SOME LIGHTNING.. DRY CONDITIONS IN BETWEEN
SYSTEMS WITH MAINLY SCATTERED CLOUDS OVER MOUNTAINS AND URBAN
CORRIDOR. LATEST RUC SHOWS NEXT WAVE REACHING 4 CORNERS AROUND 00Z
WITH INCREASING QG ASCENT AND INSTABILITY SPREADING NORTHEAST INTO
CFWA. SHOULD SEE SOME CONVECTION REDEVELOPING ACROSS MOUNTAINS BY
THE AFTERNOON...SPREADING ACROSS PLAINS DURING THE AFTERNOON.
CAPES INITIALLY NOT ALL THAT IMPRESSIVE...GENERALLY UNDER
1000 J/KG. STILL POTENTIAL FOR SOME SMALL HAIL AND GUSTY
WINDS WITH THE STORMS THIS AFTERNOON. BEST CHANCE FOR SEVERE STILL
LOOKING ALONG AND EAST OF A FORT MORGAN TO LIMON LINE THIS EVENING
WHEN LOW LEVEL SOUTHEASTERLIES WILL BE CRANKING AND INCREASING THE
SHEAR WITH POTENTIAL FOR A FEW TORNADOES. OVERALL CURRENT
FORECASTS SEEM ON TRACK...WILL MAKE MINOR ADJUSTMENTS TO CURRENT
CONDITIONS.
&&
.AVIATION...WINDS A BIT MORE SOUTHERLY BEHIND EXITING
SYSTEM...SHOULD SHIFT TO THE SOUTHEAST AS LOW LEVEL WINDS INCREASE
AHEAD OF APPROACHING TROUGH. SCATTERED SHOWERS AND STORMS TO
BEGIN DEVELOPING OVER MOUNTAINS BY THE AFTERNOON...SPREADING
ACROSS THE DENVER AREA DURING THE AFTERNOON. CURRENT TAF TRENDS
STILL LOOKING ON TRACK...WITH FIRST BATCH OF STORMS AROUND 20Z
THEN ANOTHER ROUND NEAR 01Z. GUSTY OUTFLOW WINDS TO 40 KTS STILL
POSSIBLE WITH THE STORMS. VFR CONDITIONS TO PREVAIL...THOUGH
CEILINGS AROUND 7000 FEET AGL POSSIBLE.
&&
.HYDROLOGY...SHOWERS AND STORMS POSSIBLE ACROSS MOUNTAINS AND
FOOTHILLS THOUGH THIS EVENING...CAPABLE OF PRODUCING RAINFALL
AMOUNTS OF UP TO A QUARTER OF AN INCH IN 30 MINUTES OR LESS.
STORMS ARE EXPECTED TO BE FAST MOVING...SO FLOODING IS NOT ANTICIPATED.
&&
.PREV DISCUSSION... /ISSUED 454 AM MDT THU APR 26 2012/
SHORT TERM...AT THIS HOUR...A WEAK MID-LEVEL SHORT WAVE WAS PASSING
OVER EXTREME EASTERN CO AND A SFC LOW WAS CENTERED JUST EAST OF
PUEBLO. THE TWO HAVE COMBINED TO GENERATE SOME QG-LIFT AND
UPSLOPE FLOW WHICH AS RESULTED IN A COUPLE BANDS OF LIGHT/MODERATE
RAINFALL FROM JUST EAST OF DENVER TO THE KANSAS LINE. SHOWERS HAVE
SHOWN SOME STRENGTHENING IN THE PAST HOUR AS THEY DRIFT NORTHEAST
INTO DEEPER MOISTURE. AT THEIR PRESENT SPEED SHOULD SEE MOST OF
THESE SHOWERS MOVING OUT OF THE FCST AREA BY 14Z THIS MORNING.
BEFORE THEY DO COULD SEE A COUPLE LOW TOP T-STORMS POP UP.
SYNOPTICALLY...A SHARPLY CURVED UPPER LEVEL SHORT WAVE TROUGH/LOW
COMING ONSHORE IN SOUTHERN CALIFORNIA AT THIS TIME IS PROGGED TO
RACE EAST-NORTHEASTWARD PASSING OVER THE 4-CORNERS AREA AROUND 00Z
TODAY...AND EVENTUALLY OVER NORTHEAST COLORADO SOMETIME BETWEEN
06Z AND 09Z TONIGHT. LOOKS AS THOUGH WE COULD SEE TWO ROUNDS OF
CONVECTION/T-STORM DEVELOPMENT PRIOR ITS ARRIVAL. FIRST ROUND OF
STORMS EXPECTED TO FORM OVER THE MTNS AND FRONT RANGE FOOTHILLS BY
EARLY THIS AFTERNOON WITH STG DAYTIME HEATING. THAT/S ASSUMING THE
OVERLYING CIRRUS CLOUD SHIELD DOESN/T BECOME TOO THICK BEFORE
CONVECTIVE TEMPERATURES ARE REACHED. INCREASING SWLY FLOW ALOFT
SHOULD MOVE THIS CONVECTION OUT OVER THE PLAINS DURING THE
AFTERNOON. DUE TO LIMITED LOW-LEVEL MOISTURE ON THE PLAINS AT THAT
TIME CAPE VALUES ARE PRESUMABLY UNDER 1000 J/KG. STILL SUFFICIENT
ENOUGH TO GENERATE STORM UPDRAFTS CAPABLE OF SMALL HAIL AND BRIEF
MODERATE TO HEAVY RAINFALL. ABI IR 10.35U SAT LOOP SHOWS THIS
DEVELOPMENT AND PROGRESSION NICELY. THIS FIRST WAVE OF STORMS
LIKELY TO REACH THE EASTERN BORDER OF CO BY 00Z/TODAY. MODELS AND
THE ARI SAT LOOP THEN SHOW A SECOND WAVE OF T-STORMS ASSOCIATED
WITH THE UPPER TROUGH MOVING OUT OF THE CNTRL COLORADO MTNS AND
ONTO THE NERN PLAINS OF CO DURING THE EVENING HOURS. BY THAT
TIME...LOW LEVEL MOISTURE ON THE PLAINS SHOULD HAVE INCREASED
CONSIDERABLY WITH STG S-SELY BNDRY LAYER FLOW ON THE WRN EDGE OF A
35-45KT LOW LEVEL JET ALONG THE CO/KS BORDER. LOW LEVEL SHEAR
LOOKS QUITE IMPRESSIVE ON MODEL SOUNDS IN THIS AREA...BUT CAPES
ONLY SLIGHTLY BETTER THAN THOSE PROGGED FOR EARLIER IN THE DAY.
NEVERTHELESS...COUNTING ON AT LEAST ISOLATED SEVERE T-STORMS/
SUPERCELLS CAPABLE OF LARGE HAIL...POTENTIALLY DAMAGING WINDS AND
EVEN A WEAK TORNADO OR TWO WITH FAVORABLE SHEAR PROFILE IN PLACE.
BEST CHANCE FOR SVR APPEARS TO EXIST EAST OF A FORT MORGAN-TO-
LIMON LINE. SPC CONVECTIVE DAY-1 OUTLOOK HAS THIS AREA IN A SLIGHT
RISK. NO ARGUMENT WITH THAT.
IN THE HIGH COUNTRY FALLING TEMPERATURES OVERNIGHT WITH THE PASSING
TROUGH SHOULD DROP THE SNOW LEVEL TO AROUND 8500 OR 9000 FEET BY
MORNING. THE HIGHER MTN RIDGES AND PASSES COULD PICK UP A FEW
INCHES OF SNOW BY MORNING. AS FOR HIGH TEMPERATURES TODAY...GOING
FOR MID TO UPPER 70S ON THE PLAINS AND 45 TO 60 IN THE HIGH
COUNTRY...ASSUMING WE SEE ENOUGH SUNSHINE. THAT/S STILL SEVERAL
DEGS ABOVE AVERAGE FOR THE DATE.
LONG TERM...THE UPPER LOW WILL MOVE OVER NORTHEAST COLORADO
FRIDAY MORNING THEN STRONG DRYING AND SUBSIDENCE KICKS IN BY
AFTERNOON BEHIND THE LOW. THE MAIN CONCERN FOR THE FRIDAY PERIOD
IS THE POTENTIAL FOR HIGH WINDS. FAIRLY DECENT QG DOWNWARD FORCING
WITH THIS EJECTING LOW BUT QUESTIONABLE ON HOW STRONG THE WINDS
MAY GET. THE GFS IS STRONGER THAN THE NAM BUT AT THIS TIME WILL
PLAY SPEEDS JUST UNDER HIGH WIND CRITERIA. LOOKS LIKE THE
STRONGEST WINDS WILL BE NEAR THE WYOMING BORDER AND THEN SPILLING
OUT OVER THE NORTHEAST PLAINS. THE URBAN CORRIDOR LOOKS TO BE A
BIT LIGHTER ON THE SPEEDS. ONCE THE LOW GETS ONSHORE THIS MORNING
NEXT SHIFT MAY BE ABLE TO SEE IF INDEED THERE IS ENOUGH WIND TO
WARRANT ANY HILITES. THE WINDS WILL BE ON THE DECLINE FRIDAY
EVENING AS THE LOW PULLS FURTHER AWAY. SATURDAY WILL START OUT DRY
BUT THE NEXT WAVE ROTATING AROUND THE MAIN LOW WILL MOVE INTO
COLORADO SATURDAY NIGHT. OVERALL MOISTURE AND INSTABILITY LOOK
MARGINAL AND WILL CONTINUE WITH SLIGHT CHANCE POPS OVER THE PLAINS
FOR ALL OF SATURDAY NIGHT AND SUNDAY.
FROM MONDAY THROUGH THE MIDDLE OF NEXT WEEK COLORADO WILL BE UNDER
A MODERATE WESTERLY FLOW WITH WEAK RIPPLES IN THE FLOW. ENOUGH
MOISTURE TO KEEP THE MENTION OF SHOWERS/STORMS IN THE FORECAST.
TEMPERATURES THROUGH THE PERIOD WILL BE AROUND NORMALS OR JUST A
BIT ABOVE.
AVIATION...LIGHT DRAINAGE WINDS THIS MORNING BECOME SOUTHEASTERLY
AND INCREASE IN SPEED THIS AFTERNOON. SCATTERED THUNDERSTORMS ARE
EXPECTED TO BEGIN FORMING OVER THE HIGHER TERRAIN TO THE WEST AND
SOUTHWEST OF DENVER AROUND 19Z TODAY. SOUTHWEST FLOW ALOFT WILL
CARRY THESE STORMS ACROSS THE DENVER METRO AREA DURING THE
AFTERNOON...SOME CAPABLE OF SMALL HAIL...FREQUENT LIGHTNING AND
WIND GUSTS TO AROUND 40KTS. THIS FIRST WAVE OF STORMS IS EXPECTED
TO MOVE EAST OF THE METRO AREA BY 00Z...ONLY TO BE FOLLOWED BY A
SECOND WAVE OF SHOWERS AND T-STORMS WITH THE UPPER LEVEL TROUGH.
THESE STORMS AREA NOT EXPECTED TO PRODUCE AS MUCH RAIN OR
WIND...AT LEAST NOT UNTIL THEY MOVE FARTHER OUT ONTO THE PLAINS
WHERE THE AIRMASS WILL BE FAR MORE MOIST AND UNSTABLE. CONDITIONS
ARE LIKELY TO IMPROVE IN THE DENVER AREA AFTER 06Z WITH THE
DEVELOP OF A DRY AND GUSTY DOWNSLOPE FLOW OFF THE FOOTHILLS.
HYDROLOGY...SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON
WILL BE CAPABLE OF RAINFALL AMOUNTS UP TO A QUARTER INCH UNDER 20
MINUTES. SHOWERS THIS EVENING MAY LAY DOWN ANOTHER QUARTER INCH OF
RAIN IN UNDER AN HOUR BEFORE MOVING ON. DUE THE FAIRLY FAST
MOVEMENT OF THESE STORMS...FLOODING RAINFALL IS NOT ANTICIPATED IN
THE BURN AREAS ALONG THE FRONT RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS ALBANY NY
1047 AM EDT THU APR 26 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE EASTWARD ACROSS THE EASTERN GREAT
LAKES THIS AFTERNOON...THEN TRACK ACROSS NORTHERN NEW YORK STATE AND
NEW ENGLAND TONIGHT. THIS SYSTEM WILL BRING RAIN SHOWERS TO MUCH OF
THE AREA LATE THIS AFTERNOON THROUGH THIS EVENING. THE LOW WILL
STRENGTHEN CONSIDERABLY AS IT LIFTS INTO THE CANADIAN MARITIMES ON
FRIDAY...RESULTING IN WINDY AND COOL CONDITIONS ACROSS OUR REGION.
HIGH PRESSURE OVER THE UPPER GREAT LAKES AND MIDWEST WILL KEEP US
DRY AND UNSEASONABLY COOL THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1047 AM EDT...CLOUDS HAVE BEGUN TO INCREASE ACROSS SOUTHERN
AND WESTERN AREAS...HOWEVER...MOSTLY CLEAR SKIES ARE STILL IN
PLACE FROM THE CAPITAL REGION NORTHEASTWARD. CLOUDS WILL START TO
INCREASE DURING THE NEXT FEW HOURS...WITH MOST AREAS MOSTLY CLOUDY
OR CLOUDY BY MID AFTN. THE LATEST LOCAL ESTFWRF AND 3KM HRRR BOTH
SHOW RAIN SHOWERS MAKING THEIR WAY INTO THE WESTERN ADIRONDACKS BY
THE MID AFTN. HOWEVER...IT MAY TAKE UNTIL THE EVENING FOR SHOWERS
TO REACH THE CAPITAL REGION AND POINTS SOUTH AND EAST...SO HAVE
ADJUSTED POPS TO SHOW MAINLY CHC POPS FOR MUCH OF THE AFTN...WITH
LIKELY/CATEGORICAL POPS NOT ARRIVED TILL ALMOST 00 UTC.
TWO SEPARATE SYSTEMS WILL BE AFFECTING THE EASTERN CONUS THIS
AFTERNOON INTO TONIGHT. THE FIRST SYSTEM IS A POTENT SHORT WAVE
TROUGH EMBEDDED IN NW ZONAL FLOW ACROSS CURRENTLY OVER THE
OHIO/WV AREA. AHEAD OF THIS SYSTEM SEVERAL BOUTS OF CONVECTION
HAVE BEEN FIRING THIS MORNING DOWNSTREAM OVER THE MID ATLANTIC
REGION. THERE IS A DISTINCT AIR MASS CHANGE TO THE SOUTH OF THE
MASON DIXON LINE...WITH GREATER MOISTURE AND INSTABILITY. THE AIR
MASS OVER THE NORTHEAST WILL REMAIN MORE STABLE.
THE SYSTEM THAT WE WILL BE DEALING WITH IN THE NORTHEAST CONUS IS A
NORTHERN STREAM SHORT WAVE TROUGH ROUNDING THE BASE OF AN UPPER
LEVEL LOW MOVING INTO QUEBEC. THIS WAVE IS CURRENTLY MOVING ACROSS
THE EASTERN GREAT LAKES. ISENTROPIC LIFT ASSOCIATED WITH THIS
SYSTEM WILL BE RESPONSIBLE FOR THE SHOWERS THIS AFTERNOON. THE
SURFACE LOW SHOULD TRACK NORTH OF THE AREA...SO SOME MILDER AIR
WILL BRIEFLY MOVE OVERHEAD. WITH RAIN DELAYED UNTIL LATER IN THE
AFTERNOON OR EVENING...WILL FORECAST WARMER TEMPS THAN PREVIOUSLY
FORECAST WITH GENERALLY LOWER 60S FOR MOST VALLEY LOCATIONS
POSSIBLY MID 60S SOUTH OF ALBANY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THE SYSTEM MENTIONED IN THE NEAR TERM WILL PASS THROUGH DURING THE
EVENING HOURS...WITH RAIN CONTINUING THROUGH AROUND MIDNIGHT THEN
TAPERING OFF IN MOST AREAS THEREAFTER. THE ONLY EXCEPTION WILL BE
ACROSS THE HIGHER TERRAIN MAINLY NORTH OF THE CAPITAL REGION...WHERE
WRAP-AROUND MOISTURE AND A NORTHWESTERLY UPSLOPE FLOW WILL RESULT IN
SCATTERED TO NUMEROUS RAIN SHOWERS CHANGING TO SNOW SHOWERS AS
COLDER AIR FILTERS IN. ANY ACCUMULATIONS WILL BE VERY MINOR AND OVER
THE MOUNTAINOUS AREAS. WEST-NORTHWEST WINDS WILL START TO INCREASE
SUBSTANTIALLY AFTER MIDNIGHT AS LOW PRESSURE DEEPENS AS IT MOVES
INTO NORTHERN NEW ENGLAND AND SPRAWLING HIGH PRESSURE STARTS TO
BUILD SOUTHWARD FROM CENTRAL CANADA INTO THE GREAT LAKES.
FRIDAY WILL BE A COOL AND WINDY DAY ACROSS THE AREA...AS SURFACE LOW
PRESSURE CONTINUES TO DEEPEN AS IS MOVES FROM NORTHERN MAINE INTO
THE CANADIAN MARITIMES. THE AFOREMENTIONED RIDGE WILL NOT MAKE MUCH
EASTWARD PROGRESS...THUS RESULTING IN A STRENGTHENING PRESSURE
GRADIENT. WINDS WILL BECOME STRONG AND GUSTY BY LATE MORNING AND
ESPECIALLY DURING THE AFTERNOON. ADVISORY LEVEL WINDS OF OVER 30 MPH
SUSTAINED AND 45+ MPH GUSTS MAY OCCUR...ESPECIALLY ACROSS THE
SOUTHERN 2/3 OF THE AREA. THE ONLY POTENTIAL MITIGATING FACTOR WILL
BE MIXING DEPTHS MAY BE RATHER SHALLOW ESPECIALLY IF AN EXPANSIVE
STRATOCU CLOUD DECK FORMS IN THE CYCLONIC FLOW REGIME. STILL HAVE
ENOUGH CONFIDENCE TO MENTION POTENTIAL FOR ADVISORY LEVEL WINDS IN
THE HWO. TEMPS WILL BE AROUND 10-15 DEGREES BELOW NORMAL FOR HIGHS
WITH THE WIND MAKING IT FEEL EVEN COLDER. SOME LINGERING UPSLOPE
RAIN/SNOW SHOWERS WILL LINGER OVER FAVORED AREAS ESPECIALLY THROUGH
THE MORNING BUT SHOULD TEND TO DIMINISH DURING THE AFTERNOON AS
DRIER AIR STARTS TO WORK IN.
WINDS WILL START TO DECREASE FRIDAY NIGHT AS THE PRESSURE GRADIENT
SLACKENS SOMEWHAT WITH THE LOW MOVING FARTHER AWAY FROM THE REGION.
COLD TEMPS WILL BE THE MAIN STORY...AS DESPITE A LINGERING
BREEZE...A WIDESPREAD ADVECTIVE FREEZE IS EXPECTED ACROSS THE ENTIRE
AREA. WILL MENTION POTENTIAL FOR EVENTUAL FREEZE WARNINGS IN THE HWO.
DRY AND COOL CONDITIONS WILL CONTINUE THROUGH SATURDAY AS NORTHERN
STREAM NW FLOW PERSISTS. ALL SOURCES OF MODEL GUIDANCE CONTINUE TO
INDICATE AN WEST-EAST ORIENTED FRONTAL BOUNDARY WITH WEAK WAVES
MOVING ALONG THIS BOUNDARY TO BE CONFINED TO AREAS SOUTH OF OUR
REGION TOWARDS THE MID ATLANTIC. SOME ADDED CLOUD COVER WILL BE
POSSIBLE SATURDAY AFTERNOON FROM THIS SYSTEM BUT CONDITIONS SHOULD
REMAIN DRY. TEMPS ARE ONLY EXPECTED TO WARM A FEW DEGREES FROM
FRIDAY`S READINGS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A LARGE AND UNSEASONABLY COLD CANADIAN HIGH PRESSURE SYSTEM WILL BE
OVER THE REGION SATURDAY NIGHT THROUGH SUNDAY NIGHT. AS THE HIGH
MOVES OFF THE NEW ENGLAND COAST MONDAY...TEMPS WILL BEGIN TO
MODERATE MONDAY INTO TUESDAY...BUT THE HIGH WILL STILL BE CLOSE
ENOUGH FOR DRY WEATHER TO CONTINUE THROUGH TUESDAY. LOWS SATURDAY
NIGHT WILL GENERALLY BE BETWEEN 20S AND 30...WITH SOME UPPER TEENS
OVER THE ADIRONDACKS. HIGHS SUNDAY IN THE 40S TO THE MID 50S. LOWS
SUNDAY NIGHT IN THE 20S TO LOWER 30S. THE WARMUP WILL BEGIN MONDAY
WITH HIGHS IN THE UPPER 40S TO AROUND 60. LOWS MONDAY NIGHT WILL BE
IN THE 30S...AND HIGHS TUESDAY IN THE MID 50S TO MID 60S. AFTER THE
SYSTEM PASSES BY TO OUR SOUTH SATURDAY NIGHT...SKIES WILL BEGIN TO
CLEAR...AND EXPECT MAINLY CLEAR TO CLEAR CONDITIONS SUNDAY THROUGH
MONDAY NIGHT...AND MOSTLY TO PARTLY SUNNY ON TUESDAY.
THE WARMUP WILL CONTINUE INTO WEDNESDAY...BUT THERE WILL ALSO BE
INCREASING MOISTURE AS THE SOUTHERLY FLOW PERSISTS AND A FRONTAL
BOUNDARY APPROACHES FROM THE WEST. LOWS TUESDAY NIGHT WILL BE IN THE
UPPER 30S TO MID 40S. HIGHS WEDNESDAY IN THE UPPER 50S TO MID 60S.
SKIES WILL BE PARTLY TO MOSTLY CLOUDY.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS EXPECTED THROUGH MID MORNING. CLOUDS WILL THEN
INCREASE AND LOWER AHEAD OF AN APPROACHING WARM FRONT FROM THE
SOUTHWEST. RAIN WILL MOVE IN DURING THE MID TO LATE AFTERNOON.
CONDITIONS WILL INITIALLY REMAIN VFR IN THE RAIN...BUT EXPECT MVFR
CONDITIONS TO MOVE INTO THE KGFL/KALB/KPOU TAF SITES AROUND 21Z-
22Z...AND LOWER TO IFR CIGS AFTER 27/0000Z. BETWEEN 04Z AND 06Z
CIGS/VSBYS WILL IMPROVE TO VFR AS STRONG NW WINDS BEGIN TO BLOW.
SURFACE WINDS TODAY WILL BECOME SOUTH AND INCREASE TO 8 TO 12
KTS...WITH GUSTS OF 15 TO 20 KTS AT KGFL AND KALB DURING THE
AFTERNOON. DURING THURSDAY EVENING WINDS WILL SHIFT TO WESTERLY
AT AROUND 10 KTS...AND AFTER MIDNIGHT THE WINDS WILL BEGIN TO
INCREASE...REACHING SPEEDS OF 10 TO 15 KTS WITH GUSTS TO 25 KTS.
.OUTLOOK...
FRI...VFR. VERY WINDY.
FRI NIGHT-MON...VFR...NO SIG WX.
&&
.FIRE WEATHER...
LOW PRESSURE WILL MOVE EASTWARD ACROSS THE EASTERN GREAT LAKES
TODAY...THEN TRACK ACROSS NORTHERN NEW YORK STATE AND NEW ENGLAND
TONIGHT. THIS SYSTEM WILL BRING RAINFALL TO MUCH OF THE AREA LATE
THIS AFTERNOON THROUGH THIS EVENING. THE LOW WILL STRENGTHEN
CONSIDERABLY AS IT LIFTS INTO THE CANADIAN MARITIMES ON
FRIDAY...RESULTING IN WINDY AND COOL CONDITIONS ACROSS OUR REGION.
RELATIVE HUMIDITY VALUES WILL DROP TO A MINIMUM OF AROUND 35 TO 45
PERCENT THIS AFTERNOON. RH VALUES WILL INCREASE TO 80 TO 100 PERCENT
TONIGHT...THEN DROP TO BETWEEN 30 AND 45 PERCENT FRIDAY AFTERNOON.
WINDS TODAY WILL BE SOUTHERLY AROUND 10 TO 15 MPH. WINDS TONIGHT
WILL SHIFT TO THE WEST AND INCREASE TO 10 TO 20 MPH WITH GUSTS TO 30
MPH. WINDS ON FRIDAY WILL BECOME WEST-NORTHWEST AND INCREASE FURTHER
TO BETWEEN 20 TO 30 MPH WITH GUSTS OF 40+ MPH LIKELY.
&&
.HYDROLOGY...
LOW PRESSURE APPROACHING FROM THE UPPER GREAT LAKES WILL BRING A
FAIRLY WIDESPREAD RAINFALL TO THE AREA THIS AFTERNOON INTO THIS
EVENING. FORECAST AMOUNTS EXPECTED TO BE AROUND ONE TENTH TO ONE
QUARTER OF AN INCH FROM ALBANY SOUTHWARD...WITH ONE QUARTER TO ONE
HALF INCH NORTH. THESE RAINFALL AMOUNTS WILL HAVE LITTLE EFFECT ON
THE RIVERS...WITH SOME SLIGHT RISES POSSIBLE ACROSS THE UPPER
MOHAWK...ADIRONDACK AND UPPER HUDSON BASINS.
SOME LIGHT RAIN/SNOW SHOWERS POSSIBLE OVER THE HIGHER TERRAIN LATE
TONIGHT. OTHERWISE DRY AND WINDY CONDITIONS ARE EXPECTED FOR FRIDAY.
DRY WEATHER IS EXPECTED TO LAST THROUGH THE WEEKEND AND INTO EARLY
NEXT WEEK AS WELL.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.EQUIPMENT...
DUAL-POLARIZATION UPGRADE STARTED MONDAY...APRIL 23RD...FOR THE NWS
ALBANY RADAR KENX AND THE RADAR WILL BE OUT OF SERVICE THROUGH AT
LEAST FRIDAY.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/JPV
NEAR TERM...FRUGIS/KL/JPV
SHORT TERM...JPV
LONG TERM...GJM
AVIATION...KL/GJM
FIRE WEATHER...JPV
HYDROLOGY...JPV
EQUIPMENT...WFO ALY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
748 AM EDT THU APR 26 2012
.SYNOPSIS...
A DEEP LAYERED RIDGE WILL REMAIN TO THE SOUTH...WHILE A COLD FRONT
DRIFTS INTO THE FORECAST AREA FRIDAY AND LIFTS NORTH ON SATURDAY.
A COLD FRONT WILL MOVE INTO THE AREA LATE SUNDAY INTO MONDAY...AS
HIGH PRESSURE BUILDS IN FROM THE NORTH THROUGH THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DAYBREAK...BROKEN CLOUDS ACROSS THE REGION WITH TEMPS IN THE LOWER
TO MID 60S AND WINDS ALREADY GUSTING IN A FEW AREAS GIVEN THE 35-40
KT OF WIND IN THE FIRST 2 KFT FEET OF THE ATMOSPHERE. RADAR HAS
SHOWN SOME RETURNS WHICH ARE LIKELY VIRGA.
AN EXCELLENT SETUP TODAY FOR BREEZY TO WINDY CONDITIONS TO
DEVELOP ACROSS THE FORECAST AREA AS A STRONG SHORT WAVE MOVES INTO
THE MID ATLC REGION AND A LONGWAVE TROUGH DIPS THROUGH THE GREAT
LAKES. THESE FEATURES AND THE PRESENCE OF A LARGE DEEP LAYERED
SUBTROPICAL RIDGE TO OUR S WILL ACT TO TIGHTEN THE LOW LEVEL PRES
GRADIENT. LOW LEVEL FIELDS ARE SUBSTANTIAL ON THE ORDER OF 40 TO
50 KT WITH THE NAM INDICATING CLOSE TO 40 KT OF MEAN WIND AROUND
CHARLESTON AT 18Z BETWEEN 925 MB AND 800 MB. WE HAVE ISSUED
A WIND ADVISORY TODAY FOR OUR NORTHERN ZONES INCLUDING AND
CENTERED ON THE CHARLESTON AREA. THE LATEST RUC SHOWS 925 MB
EVEN STRONGER AND MORNING CLOUDS ARE EXPECTED TO GIVE WAY
TO DEEP MIXING THIS AFTERNOON AND STRONG GUSTY SOUTHWEST WINDS
WHICH WILL PROVE FOR DIFFICULT DRIVING ON BRIDGES AND OVERPASSES.
HIGHS TODAY SHOULD SOAR TO MID TO UPPER 80S GIVEN LOW LEVEL
THICKNESS VALUES AROUND 90 DEGREES AND MORE SUNSHINE ANTICIPATED
THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
A SECONDARY SHORT WAVE IS PROGGED TO DIVE SE THROUGH THE MID ATLC
AREA TO OUR N TONIGHT AND SOME CONVECTION MAY BRUSH PARTS OF THE
CAROLINAS WELL TO OUR N. SOME CLOUDS AND MILD TEMPS WILL PREVAIL
ONCE AGAIN WITH A BREEZY EVENING IN PARTS OF COASTAL SOUTH
CAROLINA AND WINDS DIMINISHING AFTER DUSK ELSEWHERE. WINDS SHOULD
CONTINUE TO DIE DOWN IN THE OVERNIGHT HOURS. TEMPS WILL BE IN
THE 60S ALL AREAS.
FRIDAY...LATEST 00Z MODEL GUIDANCE IS NOW INDICATING THAT THE
BACKDOOR FRONT LINGERING TO THE NORTH COULD DESCEND TO THE SANTEE
RIVER BY FRIDAY AFTERNOON. DEEP MOISTURE WILL ALSO INCREASE ALONG
THE BOUNDARY AS THE DAY PROGRESSES...THE RESULT OF A DECENT
SHORTWAVE TRACKING INTO THE AREA ALONG NEARLY ZONAL FLOW ALOFT.
HAVE INTRODUCED A SLIGHT CHANCE FOR SHOWERS/THUNDERSTORMS FRIDAY
AFTERNOON ACROSS AREAS NORTH OF THE SAVANNAH RIVER...AS THESE
LOCATIONS WILL BE CLOSEST THE MEANDERING FRONT AND ITS ASSOCIATED
CONVERGENCE. ONCE THE SHORTWAVE PASSES ACROSS THE SOUTHEAST STATES
FRIDAY NIGHT...THE FRONT WILL ONCE AGAIN DRIFT NORTH OF THE
FORECAST AREA...WITH RAIN CHANCES DECREASING FROM SOUTH TO NORTH
ACCORDINGLY.
HIGH TEMPERATURES ON FRIDAY COULD BE IMPACTED BY THE LOCATION OF
THE BACKDOOR FRONT. WILL INDICATE TEMPERATURES REACHING THE LOW
TO MID 80S FAR NORTH WHERE THE FRONT COULD LINGER...WHILE
CONDITIONS WARM INTO THE UPPER 80S ACROSS SOUTHEAST GEORGIA.
SATURDAY...THE BACKDOOR FRONT WILL CONTINUE TO LIFT FARTHER NORTH
OF THE FORECAST AREA...WITH DEEP MOISTURE AND CONVERGENCE ALSO
MOVING AWAY FROM THE REGION. UPPER RIDGING ACROSS THE BAHAMAS
WILL BUILD BACK INTO THE REGION ON SATURDAY...AND WITH A NOTABLE
AREA OF NEGATIVE VORTICITY OPENING OVER SOUTHEAST SOUTH CAROLINA
AND SOUTHEAST GEORGIA...RAIN CHANCES WILL BE LESS THAN 10 PERCENT.
RISING HEIGHTS ALOFT AND CONTINUED WARM SOUTH/SOUTHWEST FLOW WILL
SUPPORT HIGH TEMPERATURES WELL ABOVE SEASONAL NORMALS...REACHING
THE UPPER 80S AWAY FROM THE LOCALLY COOLER COASTLINE.
SUNDAY...A SHORTWAVE TROUGH WILL DESCEND FROM EASTERN CANADA INTO
THE NEW ENGLAND STATES ON SUNDAY...WHILE STRONG CANADIAN SURFACE
HIGH PRESSURE SLIPS INTO THE GREAT LAKES REGION AND GRADUALLY
BUILDS DOWN THE EAST COAST. THE WEAK BOUNDARY TO THE NORTH WILL BE
OVERCOME BY A STRONGER COLD FRONT ALONG THE LEADING EDGE OF THE
CANADIAN HIGH...PROGRESSING INTO THE FORECAST AREA SUNDAY NIGHT.
THE MAJORITY OF COLD ADVECTION WITH THIS FRONT IS EXPECTED TO BE
DELAYED UNTIL AT LEAST THE SUNDAY EVENING HOURS...AND WILL THUS
MAINTAIN A HIGH TEMPERATURE FORECAST IN THE MID TO UPPER 80S.
PRECIPITATION POTENTIAL ASSOCIATED WITH THE PROGRESSION OF THE
FRONT IS MUCH MORE UNCERTAIN...AS STRONG RIDGING FROM THE SOUTH
WILL PERSIST WHILE DEEP MOISTURE LOOKS QUITE LIMITED. HAVE THUS
INDICATED ONLY SLIGHT CHANCE POPS SUNDAY AND SUNDAY NIGHT FOR
PORTIONS OF THE FORECAST AREA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
MONDAY...DUE TO SOME TIMING DIFFERENCES BETWEEN MEDIUM RANGE MODEL
SOLUTIONS REGARDING THE PROGRESSION OF THE COLD FRONT FROM THE
NORTH...HAVE CAPPED RAIN CHANCES BELOW 15 PERCENT ON MONDAY.
NOTABLE COLD ADVECTION BEHIND THE DESCENDING FRONT WILL SUPPORT
COOLER HIGH TEMPERATURES...RANGING FROM THE MID 70S CHARLESTON
TRI COUNTY REGION TO THE LOWER 80S FAR SOUTHEAST GEORGIA.
TUESDAY THROUGH THURSDAY...THE SURFACE HIGH TO THE NORTH WILL
STEADILY SHIFT OFF THE NEW ENGLAND AND MID ATLANTIC COASTLINE
TUESDAY THROUGH MID WEEK...WHILE STRONG UPPER RIDGING REMAINS IN
CONTROL OF THE PATTERN ALOFT. WINDS WILL VEER AROUND TO EAST AND
SOUTHEAST TUESDAY THROUGH THURSDAY...SUPPORTING HIGH TEMPERATURES
RISING BACK INTO THE LOW TO MID 80S BY MID WEEK. WILL CAP RAIN
CHANCES BELOW 15 PERCENT THROUGH THE EXTENDED PERIOD...CONSIDERING
THE DEEP UPPER RIDGING AND ASSOCIATED SUBSIDENCE PERSISTING INTO
MID WEEK.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z/27.
THE LOW LEVEL INVERSION WILL BREAK SHORTLY GIVING WAY TO A WINDY
DAY. THE STRONGEST GUSTS WILL OCCUR AT KCHS DURING THE AFTERNOON...
REACHING 30-35 KT AT TIMES...WHEREAS GUSTS AT KSAV SHOULD TOP OUT
AROUND 25 KT THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS EXPECTED TO PREVAIL.
&&
.MARINE...
PERIODIC SMALL CRAFT ADVISORY CONDITIONS WERE A BIT OF SURPRISE
OVERNIGHT AT GRAYS REEF OVERNIGHT BUT SW FLOW DURING THIS TIME OF
YEAR CAN OFTEN PRODUCE LOCALIZED NOCTURNAL ROLLING AND JETTING OFF
OUR COAST WHICH CAN LOCALLY ENHANCE WINDS DURING EVENTS WITH
STRONGER LOW LEVEL JETS.
TODAY...WE THINK THE NOCTURNAL SURGING IN THE NEAR SHORE GEORGIA
WATERS WILL EBB WELL BELOW SCA CRITERIA AS THE LAND MASS HEATS
AND MIXES WITH THE MARINE INVERSION TAKING PRECEDENCE. ELSEWHERE
SCA CONDITIONS ARE LIKELY WITH STRONG GUSTS ALONG THE LAND/SEA
INTERFACE IN COASTAL SOUTH CAROLINA AND MARGINAL SCA CONDITIONS OVER
OUTER GEORGIA WATERS. THE CHARLESTON HARBOR WILL SEE ANOTHER STRONG
RESULTANT SEA BREEZE TAKE SHAPE AND WIND WILL SURGE 20-25 KT THIS
AFTERNOON WITH LOCALLY STRONGER GUSTS A GOOD BET. THE SAVANNAH
RIVER ENTRANCE SHOULD BECOME GUSTY AT TIMES THIS AFTERNOON BUT
SPEEDS SHOULD BE STRONGER INLAND FROM THE INTRACOASTAL. SCA
CONDITIONS WILL LINGER THIS EVENING AND DIMINISH LATER TONIGHT AS
THE LOW LEVEL JET WEAKENS. WILL STILL NEED TO WATCH FOR SOME LOCAL
JETTING CONDITIONS GIVEN THE PATTERN.
A WEAK BACKDOOR FRONT COULD DRIFT INTO THE WATERS ADJACENT THE
SANTEE RIVER ON FRIDAY...BEFORE QUICKLY LIFTING BACK TO THE NORTH
BY FRIDAY NIGHT. SOUTHWEST FLOW WILL PREVAIL SATURDAY AND
SUNDAY...LIKELY INCREASING LATE SUNDAY AS A SECONDARY STRONGER
FRONT FROM NORTH THE PRESSES TOWARD THE FORECAST AREA. ALTHOUGH
THERE ARE SOME TIMING DIFFERENCES EVIDENT IN NUMERICAL MODEL
GUIDANCE...PREFER TO INDICATE THE COLD FRONT MOVING INTO THE
NORTHERN WATERS BY SUNDAY AFTERNOON AND PUSHING SOUTHWARD THROUGH
SUNDAY EVENING. DECENT COLD ADVECTION AND AN ENHANCED PRESSURE
GRADIENT COULD SUPPORT SMALL CRAFT ADVISORY WINDS AND SEAS FOR
PORTIONS OF THE WATERS LATE SUNDAY INTO MONDAY...AS NORTHEAST FLOW
SURGES BEHIND THE FRONT.
RIP CURRENTS...GIVEN THE STRONG SW FLOW ASSOCIATED WITH THE
RESULTANT SEA BREEZE TODAY...WE HAVE UPGRADED THE RIP CURRENT
RISK TO MODERATE ALONG CHARLESTON COUNTY...LOW RISK ELSEWHERE.
&&
.FIRE WEATHER...
STRONG AND GUSTY SW WINDS AND EVEN WARMER TEMPERATURES ARE
EXPECTED TODAY. HOWEVER RH/S APPEAR TO BE HIGHER THAN PREVIOUS
DAYS WITH MINIMUM VALUES ONLY FALLING INTO THE 30-40 PERCENT
RANGE. A FIRE DANGER STATEMENT WILL BE ISSUED FOR PORTIONS OF
THE FORECAST AREA GIVEN THE VERY WARM TEMPS AND GUSTY WINDS...
LOWEST RH VALUES MAINLY ALONG AND W OF I-95 THIS AFTERNOON. A
FEW AREAS IN TATTNALL...EVANS...AND CANDLER COUNTIES COULD
SEE RH DROP INTO THE 25-30 PERCENT THIS AFTERNOON...NEARING
RED FLAG CRITERIA.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...WIND ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR SCZ043>045-049-050-052.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR AMZ352.
SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR AMZ350-374.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ330.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...79
LONG TERM...79
AVIATION...
MARINE...79
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
836 PM CDT FRI APR 27 2012
.DISCUSSION...
ISSUED 836 PM CDT FRI APR 27 2012
LOW PRESSURE OVER KANSAS WILL LIFT NORTHEASTWARD TONIGHT...REACHING
NORTHEAST MISSOURI BY SATURDAY MORNING. VERY DRY AIRMASS PRECEDING
THIS FEATURE WILL KEEP CENTRAL ILLINOIS DRY THROUGH THE EVENING...WITH
SHOWERS SPREADING INTO THE AREA OVERNIGHT. LATEST RADAR
MOSAIC SHOWS SHOWERS/STORMS DEVELOPING IN THE WARM SECTOR OF THE
SYSTEM OVER NORTHWEST MISSOURI...AND THESE ARE EXPECTED TO LIFT/DEVELOP
INTO WEST-CENTRAL ILLINOIS AFTER MIDNIGHT. BASED ON CURRENT
TRAJECTORY AND LATEST HRRR DATA...THINK MAINLY THE N/NW KILX CWA
WILL BE IMPACTED. AS SUCH...HAVE ADJUSTED POPS TO GO LIKELY ALONG
AND NORTHWEST OF A JACKSONVILLE TO DANVILLE LINE...WITH ONLY
CHANCE POPS FURTHER SOUTH AND EAST. GIVEN DRY AIRMASS...CONVECTION
WILL BE WEAKENING AS IT APPROACHES...RESULTING IN MAINLY SHOWERS
WITH PERHAPS A RUMBLE OF THUNDER. UPDATED ZONES HAVE ALREADY BEEN
ISSUED.
BARNES
&&
.AVIATION...
ISSUED 652 PM CDT FRI APR 27 2012
MID/HIGH CLOUDS WILL BLANKET CENTRAL ILLINOIS THIS EVENING...AS
LOW PRESSURE OVER KANSAS TRACKS SLOWLY NORTHEASTWARD. A COUPLE
BANDS OF LIGHT PRECIP WILL LIFT THROUGH THE AREA...HOWEVER VERY
DRY LOW-LEVEL AIRMASS WILL PREVENT MEASURABLE RAINFALL FROM
REACHING THE GROUND. ONCE THE AIRMASS BEGINS TO MOISTENS FROM THE
TOP-DOWN...CEILINGS WILL LOWER LATER THIS EVENING INTO THE
OVERNIGHT HOURS. CLUSTER OF SHOWERS/STORMS CURRENTLY DEVELOPING
OVER EASTERN KANSAS WILL EVENTUALLY MOVE INTO WEST-CENTRAL
ILLINOIS BETWEEN 05Z AND 10Z...PRIMARILY IMPACTING THE WESTERN
TERMINALS. HAVE INCLUDED A TEMPO GROUP FOR SHRA AT
KPIA...KSPI...AND KBMI ACCORDINGLY...WITH ONLY VCSH FURTHER EAST.
ONCE THIS AREA OF RAIN LIFTS INTO NORTHERN ILLINOIS TOWARD
DAWN...MAINLY DRY WEATHER WILL PREVAIL THROUGH THE REMAINDER OF
THE 00Z TAF PERIOD. LOW PRESSURE IS EXPECTED TO TRACK RIGHT ACROSS
CENTRAL ILLINOIS ON SATURDAY...MAKING FOR A TRICKY CLOUD/WIND
FORECAST. THINK KPIA AND KBMI WILL REMAIN NORTH OF THE LOW
TRACK...THUS KEEPING WINDS FROM THE E/NE AND INTRODUCING LOWER
CEILINGS OF AROUND 1500FT DURING THE DAY SATURDAY.
MEANWHILE...KSPI AND KDEC SHOULD STAY ALONG/SOUTH OF THE LOW
TRACK...KEEPING THEIR WINDS FROM THE E/SE THEN EVENTUALLY SWINGING
AROUND TO THE WEST LATE IN THE DAY. AS A RESULT...HAVE NOT HIT
CEILINGS NEARLY AS HARD AT THOSE SITES...ONLY DOWN TO AROUND 3500FT.
BARNES
&&
.PREV DISCUSSION...
ISSUED 200 PM CDT FRI APR 27 2012
WATER VAPOR LOOP SHOWING TWO DISTINCT UPPER WAVES TO OUR WEST.
THE STRONGER OF THE TWO SHORTWAVES WAS LOCATED OVER SOUTHWEST
MONTANA WITH THE SECONDARY WAVE ACRS WESTERN KS...WHICH IS BEING
DRAWN NORTHWARD AS IT ENCOUNTERS A BLOCKING RIDGE ACRS THE
NORTHERN PLAINS. FURTHER EAST...A LARGE CANADIAN HIGH WAS ANCHORED
NORTH OF THE GREAT LAKES EARLY THIS AFTERNOON HELPING TO DRAWN
DOWN SOME COOL AND VERY DRY AIR SOUTH INTO OUR AREA.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
SEVERAL CONCERNS THIS FORECAST PERIOD INCLUDING...TIMING OF RAIN
ACROSS THE FORECAST AREA THIS EVENING AND THEN CONVECTION CHANCES
INCLUDING SEVERE THREAT AROUND THE I-70 CORRIDOR TOMORROW AFTERNOON.
AFTER THAT...A SERIES OF WEATHER SYSTEMS MOVE OUT OF THE SOUTHERN
PLAINS AND INTERACT WITH A FRONTAL BOUNDARY WHICH WILL BE SHIFTING
SLOWLY NORTH AS THE LARGE CANADIAN HIGH FINALLY EDGES OFF TO OUR
EAST. THIS WILL BRING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH EARLY NEXT WEEK.
FORECAST SOUNDINGS SHOWING ONLY A SLOW MOISTENING OF THE LOWER LEVELS
THIS EVENING AS THE SURFACE LOW PRESSURE AREA ASSOCIATED WITH THE KANSAS
UPPER WAVE MOVES INTO NORTHERN MISSOURI BY LATE TONIGHT. IT APPEARS
WE WILL SEE OUR BEST THREAT FOR SHOWERS AND ISOLATED THUNDERSTORMS LATE
THIS EVENING WEST...AND THEN SHIFTING NORTHEAST OVER THE REMAINDER
OF THE AREA LATE TONIGHT...BEFORE EDGING OUT OF OUR AREA BY LATE SATURDAY
MORNING AS THE SURFACE WAVE SHIFTS INTO EAST CENTRAL MO/SOUTHWEST ILLINOIS
BY NOON. LOOKS AS IF THE NAM-WRF HANGS ON TO THE IDEA OF A CLOSED SFC
WAVE TOO LONG BASED ON THE UPPER SYSTEM PULLING WELL OF TO ITS NW DURING
THE MORNING.
LOCAL HI-RES MODELS SUGGEST THE WARM FRONT WILL PUSH TO JUST SOUTH
OF I-70 BY EARLY TOMORROW AFTERNOON WITH STEEP MID LEVEL LAPSE RATES
OF UP TO 8 DEG/C AND MIXED LAYER CAPES OF 1500-2000 J/KG ALONG AND
JUST SOUTH OF THE WARM FRONT. SCATTERED STORMS ARE EXPECTED TO DEVELOP
IN THE 18Z-21Z TIME FRAME JUST EAST OF THE WEAKENING SFC WAVE AND
ALONG/JUST SOUTH OF THE WARM FRONT. AT THIS TIME...IT APPEARS THE PRIMARY
MODE OF CONVECTION TOMORROW AFTERNOON WOULD BE INITIALLY SUPERCELLUAR
WHICH WOULD QUICKLY TRANSLATE MORE INTO A LINEAR MODE BASED ON THE
UNIDIRECTIONAL WINDS FORECAST IN SE IL. PRIMARY THREAT WOULD BE LARGE
HAIL AND DAMAGING WINDS...WITH AN ISOLATED TORNADO POSSIBLE...ESP JUST
EAST OF THE SFC WAVE AND ALONG THE WARM FRONT.
ANY LINGERING CONVECTION SHOULD COME TO AN END BY 00Z ACRS SE IL WITH
THE BOUNDARY GETTING NUDGED BACK SOUTH AGAIN AS THE CANADIAN HIGH
BUILDS BACK INTO THE AREA SATURDAY EVENING. WILL CONTINUE TO HOLD
ON TO CHANCE POPS ACRS SOUTHERN IL AS THE BOUNDARY WILL NOT BE THAT
FAR AWAY. MEANWHILE...FURTHER TO THE NORTHWEST...THE UPPER LOW SHIFTS
SLOWLY NORTH INTO SOUTHERN CANADA AS THE RELENTLESS BLOCK HOLDS FIRM
ACRS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. MODELS BEGIN TO
BUILD THE HEIGHTS ACRS THE AREA IN RESPONSE TO THE RETREATING UPPER
WAVE WHICH SHOULD ALLOW THE LARGE CANADIAN HIGH TO EDGE FURTHER
EAST ON SUNDAY/SUNDAY NIGHT. THE FRONTAL BOUNDARY TO OUR SOUTH WILL
BEGIN TO PUSH BACK NORTH DURING THIS TIME FRAME WITH ALL MODELS
INDICATING WEAK DISTURBANCES MOVING OUT OF THE SOUTHERN PLAINS. ONE
SUCH WAVE WILL PUSH ALONG THE BOUNDARY AND BRING AN INCREASING
THREAT FOR SHOWERS/THUNDERSTORMS LATE SUNDAY INTO A PORTION OF MONDAY
BEFORE SHIFTING OFF TO OUR EAST MONDAY NIGHT.
LONG TERM...TUESDAY THROUGH FRIDAY
A WARMER AND ACTIVE WEATHER PATTERN CONTINUES TO BE DEPICTED ON
MEDIUM RANGE MODELS DURING THIS FORECAST PERIOD...HOWEVER...TIMING
OF INDIVIDUAL SHORTWAVES ACRS THE AREA AS THE PATTERN DEAMPLIFIES
CONTINUES TO BE A CHALLENGE WITH RESPECT TO PRECIP CHANCES EACH DAY.
PATTERN TRANSITIONS INTO MORE OF A ZONAL FLOW EARLY IN THE FORECAST
PERIOD...THEN THE UPPER FLOW SHIFTS TO SOUTHWESTERLY LATE IN THE WEEK
AS A TROF SHIFTS INTO THE WEST COAST. MOST OF OUR AREA WILL BE ALONG
THE SOUTHERN PERIPHERY OF THE STRONGER WINDS ALOFT...WHICH USUALLY
TRANSLATES TO PERIODIC CONVECTION CHANCES THIS TIME OF YEAR...AND
UNFORTUNATELY...THIS IS THE CASE THRU THE EXTENDED PORTION OF THE
FORECAST. ALTHOUGH TEMPERATURES WILL WARM WELL INTO THE 70`S TO
LOWER 80S STARTING TUESDAY...THE PATTERN CONTINUES TO SUPPORT A
LEAST MENTIONABLE POPS IN THE GRIDS EACH DAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1210 PM CDT THU APR 26 2012
.DISCUSSION...
ISSUED 948 AM CDT THU APR 26 2012
LARGE AREA OF STRATOCUMULUS HAS PUSHED SOUTHWARD INTO FAR NORTHERN
ILLINOIS. RUC MODEL LAYER HUMIDITY PLOT INDICATES SOME BREAKS
DEVELOPING AS IT MOVES INTO CENTRAL ILLINOIS AROUND MIDDAY.
ADDITIONAL DIURNAL CUMULUS EXPECTED TO FORM AROUND MIDDAY AS
WELL...ALTHOUGH CU-RULE BEGINS TO ERODE THIS BY MID AFTERNOON.
COLD-AIR ADVECTION WILL LIKELY HOLD TEMPERATURES STEADY EARLY THIS
AFTERNOON...BEFORE BEGINNING A SLOW FALL. HAVE SENT SOME UPDATES
TO THE HOURLY TEMPERATURE AND SKY GRIDS...BUT THESE DO NOT HAVE AN
IMPACT ON THE WORDED FORECASTS.
GEELHART
&&
.AVIATION...
ISSUED 1210 PM CDT THU APR 26 2012
DIURNAL STRATOCUMULUS HAS FORMED AHEAD OF A LARGER AREA OF BROKEN
CLOUDS DESCENDING FROM NORTHERN ILLINOIS. SURFACE OBSERVATIONS THE
LAST COUPLE HOURS HAS SHOWN THESE CLOUDS TO BE STEADILY RISING...
SO ANY BROKEN CEILINGS WILL BE IN THE VFR RANGE. NORTHERLY WINDS
TO CONTINUE GUSTING OVER 20 KNOTS AT TIMES THIS AFTERNOON...THEN
DIMINISH ALONG WITH THE CLOUDS TOWARD SUNSET. WINDS WILL TREND
MORE EASTERLY LATE THIS EVENING AS HIGH PRESSURE RIDGING MOVES
ACROSS THE GREAT LAKES. STORM SYSTEM CURRENTLY OVER THE PLAINS
WILL BEGIN TO SPREAD IN SOME HIGHER CEILINGS LATE TONIGHT AND
PERSIST THROUGH FRIDAY MORNING.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT THU APR 26 2012
SHORT TERM...TODAY THROUGH SUNDAY
STRONG THUNDERSTORMS HAVE JUST PASSED SE OF CLAY COUNTY WITH BRUNT
OF THUNDERSTORMS MOVING SE OF THE OHIO RIVER INTO NW KY. THESE
WERE THE STRONG TO POTENTIALLY SEVERE THUNDERSTORMS THAT AFFECTED
THE SW COUNTIES PAST 6 HOURS AND ARE EXITING WITH A SHORT WAVE. 1001
MB LOW PRESSURE OVER WEST CENTRAL INDIANA WITH ITS COLD FRONT
EXTENDING WESTWARD TO NEAR I-72. SURFACE LOW PRESSURE WILL EXIT
QUICKLY EAST INTO WESTERN PA BY NOON AND SWEEP THE COLD FRONT THRU
SE IL BY MID MORNING. 1033 MB CANADIAN HIGH PRESSURE OVER
NORTHERN PARTS OF SASKATCHEWAN AND MANITOBA AND RIDGING SOUTHWARD
INTO THE UPPER MIDWEST WILL NOSE INTO IL BY SUNSET AND PROVIDE
MOSTLY SUNNY SKIES. COOLER HIGHS TODAY RANGE FROM THE UPPER 60S
FROM I-74 NE AND 70-75 SW AREAS. TEMPS WILL SLIP QUICKER THAN
NORMAL LATER THIS AFTERNOON DUE TO COLD AIR ADVECTION ESPECIALLY
NE AREAS.
CANADIAN HIGH PRESSURE RIDGE OVER WI/IL/IN TONIGHT AND PROVIDES
FAIR AND MUCH COLDER WEATHER WITH LOWS IN THE MID TO UPPER 30S.
MET AND MAV GUIDANCE LOWS AT CHAMPAIGN ARE EVEN NEAR FREEZING.
FREEZE WATCHES ARE POSTED NE OF CENTRAL IL OVER NORTHERN INDIANA
FOR OVERNIGHT. COOLED LOWS A FEW DEGREES TONIGHT BUT DID NOT GO AS
COLD AS FREEZING YET OVER EAST CENTRAL IL SINCE WINDS DO NOT TOTALLY
GO LIGHT.
MODELS CONTINUE SLOWER WITH RETURNING CONVECTION CHANCES FRIDAY
AND LOWER POPS FRIDAY WITH DRY CONDITIONS FRIDAY MORNING WITH
20-30% CHANCE FRIDAY AFTERNOON WITH HIGHEST POPS SW AREAS FRI
AFTERNOON. THIS DUE TO LOW PRESSURE EMERGING INTO THE CENTRAL
PLAINS WITH A FRONTAL BOUNDARY JUST SOUTH OF MO/IL TRYING TO LIFT
BACK NORTH FRIDAY NIGHT INTO SOUTHERN IL AS SURFACE LOW WEAKENS AS
IT MOVES INTO SOUTHERN IL BY DAWN SAT. BEST CHANCES OF SHOWERS AND
ISOLATED THUNDERSTORMS WILL BE OVERNIGHT FRI NIGHT INTO SAT
MORNING. MUCH COOLER HIGHS IN THE MID 50S TO NEAR 60F FRI AND SAT
OVER CENTRAL IL AND LOWER 60S IN SE IL FRI AND MID TO UPPER 60S SAT.
HIGH TEMPERATURE FORECAST TRICKY OVER SE IL SAT DEPENDING ON HOW
FAR NORTH WARM FRONT GETS AND WILL BE 70S IN THE WARM SECTOR OVER
SOUTHERN IL ALONG AND SOUTH OF I-64. SHOWER CHANCES DIMINISH
OVERNIGHT SAT NIGHT THEN DRY SUNDAY WITH STILL BELOW NORMAL HIGHS
IN THE UPPER 50S AND LOWER 60S.
LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
UNSETTLED WEATHER PATTERN LOOKS TO RETURN DURING THIS TIME PERIOD
AND 00Z ECMWF MODEL IS FAVORED OVER THE DRIER GFS MODEL DUE TO ITS
RECENT BETTER TRACK RECORD. IL BACK INTO A WSW UPPER LEVEL FLOW
DURING THIS TIME WITH NEXT SHORT WAVE EJECTING NE SUNDAY NIGHT AND
CHANCES OF SHOWERS AND THUNDERSTORMS. STILL LOOKS LIKE THE BEST
CHANCES WILL BE MONDAY NIGHT THROUGH TUE EVENING WITH YET ANOTHER
SHORT WAVE EJECTING NE FROM THE CENTRAL PLAINS. TEMPS TO WARM BACK
TO ABOVE NORMAL DURING MIDDLE OF NEXT WEEK.
KH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
948 AM CDT THU APR 26 2012
.DISCUSSION...
ISSUED 948 AM CDT THU APR 26 2012
LARGE AREA OF STRATOCUMULUS HAS PUSHED SOUTHWARD INTO FAR NORTHERN
ILLINOIS. RUC MODEL LAYER HUMIDITY PLOT INDICATES SOME BREAKS
DEVELOPING AS IT MOVES INTO CENTRAL ILLINOIS AROUND MIDDAY.
ADDITIONAL DIURNAL CUMULUS EXPECTED TO FORM AROUND MIDDAY AS
WELL...ALTHOUGH CU-RULE BEGINS TO ERODE THIS BY MID AFTERNOON.
COLD-AIR ADVECTION WILL LIKELY HOLD TEMPERATURES STEADY EARLY THIS
AFTERNOON...BEFORE BEGINNING A SLOW FALL. HAVE SENT SOME UPDATES
TO THE HOURLY TEMPERATURE AND SKY GRIDS...BUT THESE DO NOT HAVE AN
IMPACT ON THE WORDED FORECASTS.
GEELHART
&&
.AVIATION...
ISSUED 658 AM CDT THU APR 26 2012
HIGH PRESSURE WILL BUILD ACROSS THE CENTRAL ILLINOIS TERMINALS
THROUGH THE 12Z TAF VALID TIME. THE HIGH AND ASSOCIATED DRY
AIRMASS WILL HELP PROVIDE VFR CONDITIONS THROUGH MOST OF THE
PERIOD. HOWEVER...WILL NEED TO KEEP AN EYE ON SOME LOW CLOUDS
UPSTREAM ACROSS THE GREAT LAKES AND UPPER MIDWEST. WHILE MUCH OF
THIS CLOUD COVER SHOULD MIX OUT TODAY...ENOUGH MAY HOLD TOGETHER
TO PRODUCE A PERIOD OF MVFR CIGS LATER TODAY. MID/HIGH CLOUD
CLOUDINESS WILL SPREAD ACROSS THE REGION FROM THE SOUTHWEST
OVERNIGHT IN ADVANCE OF THE NEXT FEATHER SYSTEM.
NORTHERLY WINDS WILL BECOME GUSTY TODAY AS DIURNAL MIXING DEEPENS.
THE WINDS ARE EXPECTED TO DIMINISH THIS EVENING AND TREND EASTERLY
AS THE CENTER OF THE SURFACE HIGH PASSES TO OUR NORTH.
BAK
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT THU APR 26 2012
SHORT TERM...TODAY THROUGH SUNDAY
STRONG THUNDERSTORMS HAVE JUST PASSED SE OF CLAY COUNTY WITH BRUNT
OF THUNDERSTORMS MOVING SE OF THE OHIO RIVER INTO NW KY. THESE
WERE THE STRONG TO POTENTIALLY SEVERE THUNDERSTORMS THAT AFFECTED
THE SW COUNTIES PAST 6 HOURS AND ARE EXITING WITH A SHORT WAVE. 1001
MB LOW PRESSURE OVER WEST CENTRAL INDIANA WITH ITS COLD FRONT
EXTENDING WESTWARD TO NEAR I-72. SURFACE LOW PRESSURE WILL EXIT
QUICKLY EAST INTO WESTERN PA BY NOON AND SWEEP THE COLD FRONT THRU
SE IL BY MID MORNING. 1033 MB CANADIAN HIGH PRESSURE OVER
NORTHERN PARTS OF SASKATCHEWAN AND MANITOBA AND RIDGING SOUTHWARD
INTO THE UPPER MIDWEST WILL NOSE INTO IL BY SUNSET AND PROVIDE
MOSTLY SUNNY SKIES. COOLER HIGHS TODAY RANGE FROM THE UPPER 60S
FROM I-74 NE AND 70-75 SW AREAS. TEMPS WILL SLIP QUICKER THAN
NORMAL LATER THIS AFTERNOON DUE TO COLD AIR ADVECTION ESPECIALLY
NE AREAS.
CANADIAN HIGH PRESSURE RIDGE OVER WI/IL/IN TONIGHT AND PROVIDES
FAIR AND MUCH COLDER WEATHER WITH LOWS IN THE MID TO UPPER 30S.
MET AND MAV GUIDANCE LOWS AT CHAMPAIGN ARE EVEN NEAR FREEZING.
FREEZE WATCHES ARE POSTED NE OF CENTRAL IL OVER NORTHERN INDIANA
FOR OVERNIGHT. COOLED LOWS A FEW DEGREES TONIGHT BUT DID NOT GO AS
COLD AS FREEZING YET OVER EAST CENTRAL IL SINCE WINDS DO NOT TOTALLY
GO LIGHT.
MODELS CONTINUE SLOWER WITH RETURNING CONVECTION CHANCES FRIDAY
AND LOWER POPS FRIDAY WITH DRY CONDITIONS FRIDAY MORNING WITH
20-30% CHANCE FRIDAY AFTERNOON WITH HIGHEST POPS SW AREAS FRI
AFTERNOON. THIS DUE TO LOW PRESSURE EMERGING INTO THE CENTRAL
PLAINS WITH A FRONTAL BOUNDARY JUST SOUTH OF MO/IL TRYING TO LIFT
BACK NORTH FRIDAY NIGHT INTO SOUTHERN IL AS SURFACE LOW WEAKENS AS
IT MOVES INTO SOUTHERN IL BY DAWN SAT. BEST CHANCES OF SHOWERS AND
ISOLATED THUNDERSTORMS WILL BE OVERNIGHT FRI NIGHT INTO SAT
MORNING. MUCH COOLER HIGHS IN THE MID 50S TO NEAR 60F FRI AND SAT
OVER CENTRAL IL AND LOWER 60S IN SE IL FRI AND MID TO UPPER 60S SAT.
HIGH TEMPERATURE FORECAST TRICKY OVER SE IL SAT DEPENDING ON HOW
FAR NORTH WARM FRONT GETS AND WILL BE 70S IN THE WARM SECTOR OVER
SOUTHERN IL ALONG AND SOUTH OF I-64. SHOWER CHANCES DIMINISH
OVERNIGHT SAT NIGHT THEN DRY SUNDAY WITH STILL BELOW NORMAL HIGHS
IN THE UPPER 50S AND LOWER 60S.
LONG TERM...SUNDAY NIGHT THROUGH WEDNESDAY
UNSETTLED WEATHER PATTERN LOOKS TO RETURN DURING THIS TIME PERIOD
AND 00Z ECMWF MODEL IS FAVORED OVER THE DRIER GFS MODEL DUE TO ITS
RECENT BETTER TRACK RECORD. IL BACK INTO A WSW UPPER LEVEL FLOW
DURING THIS TIME WITH NEXT SHORT WAVE EJECTING NE SUNDAY NIGHT AND
CHANCES OF SHOWERS AND THUNDERSTORMS. STILL LOOKS LIKE THE BEST
CHANCES WILL BE MONDAY NIGHT THROUGH TUE EVENING WITH YET ANOTHER
SHORT WAVE EJECTING NE FROM THE CENTRAL PLAINS. TEMPS TO WARM BACK
TO ABOVE NORMAL DURING MIDDLE OF NEXT WEEK.
KH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1001 PM MDT FRI APR 27 2012
.UPDATE...
ISSUED AT 1000 PM MDT FRI APR 27 2012
UPDATED THE GRIDS TO ADD PATCHY FOG OVER THE NORTHEAST CORNER OF
THE FORECAST AREA. KMCK HAS DROPPED TO 1/2SM IN THE PAST 30
MINUTES AND SHORT RANGE GUIDANCE SUPPORTS A FEW HOURS OF PATCHY
FOG. ALSO ADDED SLIGHT CHANCE POPS FOR PORTIONS OF THE FORECAST
AREA FOR THE NEXT FEW HOURS. WEAK SHOWERS HAVE RECENTLY DEVELOPED
ACROSS PORTIONS OF LINCOLN COUNTY AND HAVE MOVED INTO WESTERN
PORTIONS OF KIT CARSON AND CHEYENNE COUNTIES. WEAK H7 BAROCLINIC
ZONE AND LIMITED INSTABILITY SHOULD AID IN SUSTAINING THESE
SHOWERS AS THEY MOVE EASTWARD GENERALLY ALONG AND SOUTH OF
INTERSTATE 70. 00Z HRRR HAD A GOOD HANDLE ON THIS SO USED IT AS A
STARTING POINT. INSTABILITY DIMINISHES EVEN FURTHER SHORTLY AFTER
07Z/08Z SO HAVE PRECIP ENDING THEN.
UPDATE ISSUED AT 612 PM MDT FRI APR 27 2012
HAVE GONE AHEAD AND ALLOWED THE WIND ADVISORY TO EXPIRE AT THE TOP
OF THE HOUR. A FEW SITES TO THE NORTHWEST OF THE FORECAST AREA ARE
CLOSE TO MEETING CRITERIA BUT PRESSURE GRADIENT WILL CONTINUE TO
DIMINISH THIS EVENING AS THE AREA OF SURFACE LOW PRESSURE
CONTINUES TO MOVE AWAY FROM THE REGION. ALSO ADDED POP/WX OVER THE
SOUTHWEST FOR THE NEXT FEW HOURS WITH THE WEAK CONVECTION MOVING
ACROSS THAT AREA. TWEAKED TEMPS DOWN A DEGREE OR TWO OVERNIGHT
TONIGHT BUT NOT ANTICIPATING A FROST ADVISORY GIVEN PATCHY NATURE
EXPECTED.
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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 612 PM MDT FRI APR 27 2012
BULK OF PRECIP HAS SHIFTED EAST OF KMCK BUT WILL CARRY TEMPO FOR
THE NEXT HOUR FOR A STRAY SHOWER. AFTER THAT...SHOULD START TO SEE THE
WIND GUSTS SUBSIDE AT BOTH TERMINALS BY AROUND 02Z AS THE SURFACE
PRESSURE GRADIENT BEGINS TO RELAX. NORTHWESTERLY WINDS WILL BECOME
GUSTY AGAIN DURING THE DAY SATURDAY WITH GUSTS OF 20 TO 30 MPH.
NEXT OPPORTUNITY FOR PRECIP SHOULD HOLD OFF UNTIL AFTER THE END OF
THIS EFFECTIVE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...FOLTZ
SHORT TERM...CJS/DR
LONG TERM...DR
AVIATION...FOLTZ
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
747 PM CDT FRI APR 27 2012
...UPDATE TO AVIATION...
.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...
STRONGEST CONVECTION HAS PUSHED THROUGH ALL OF THE
TERMINALS...WITH SOME SCATTERED WEAKER CONVECTION STILL POSSIBLE
UNTIL 01Z AT KMHK AND KTOP/KFOE UNTIL 02Z AS DRYLINE MOVES
THROUGH. OTHERWISE VFR CONDITIONS BEYOND 02Z WITH WINDS GRADUALLY
DECREASING AND VEERING AROUND TO THE WEST THEN NORTH/NORTHWEST
LATER TONIGHT THRU 00Z SUNDAY.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
631 PM MDT FRI APR 27 2012
.UPDATE...
ISSUED AT 612 PM MDT FRI APR 27 2012
HAVE GONE AHEAD AND ALLOWED THE WIND ADVISORY TO EXPIRE AT THE TOP
OF THE HOUR. A FEW SITES TO THE NORTHWEST OF THE FORECAST AREA ARE
CLOSE TO MEETING CRITERIA BUT PRESSURE GRADIENT WILL CONTINUE TO
DIMINISH THIS EVENING AS THE AREA OF SURFACE LOW PRESSURE
CONTINUES TO MOVE AWAY FROM THE REGION. ALSO ADDED POP/WX OVER THE
SOUTHWEST FOR THE NEXT FEW HOURS WITH THE WEAK CONVECTION MOVING
ACROSS THAT AREA. TWEAKED TEMPS DOWN A DEGREE OR TWO OVERNIGHT
TONIGHT BUT NOT ANTICIPATING A FROST ADVISORY GIVEN PATCHY NATURE
EXPECTED.
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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 612 PM MDT FRI APR 27 2012
BULK OF PRECIP HAS SHIFTED EAST OF KMCK BUT WILL CARRY TEMPO FOR
THE NEXT HOUR FOR A STRAY SHOWER. AFTER THAT...SHOULD START TO SEE THE
WIND GUSTS SUBSIDE AT BOTH TERMINALS BY AROUND 02Z AS THE SURFACE
PRESSURE GRADIENT BEGINS TO RELAX. NORTHWESTERLY WINDS WILL BECOME
GUSTY AGAIN DURING THE DAY SATURDAY WITH GUSTS OF 20 TO 30 MPH.
NEXT OPPORTUNITY FOR PRECIP SHOULD HOLD OFF UNTIL AFTER THE END OF
THIS EFFECTIVE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...FOLTZ
SHORT TERM...CJS/DR
LONG TERM...DR
AVIATION...FOLTZ
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
620 PM CDT FRI APR 27 2012
...UPDATE TO AVIATION FOR 00Z TAFS...
.SYNOPSIS...
ISSUED AT 135 PM CDT FRI APR 27 2012
A COMPACT, YET SIGNIFICANT UPPER LOW WAS CENTERED NEAR HOXIE, KS AT
18Z. THE SURFACE LOW IN RESPONSE WAS LOCATED VERY NEAR THE UPPER
LOW CENTER. THE DOWNSLOPE MODIFIED COLD FRONT CONTINUED TO MOVE
EAST EXTENDING FROM NEAR RUSSELL TO ANTHONY IN CENTRAL TO SOUTH
CENTRAL KANSAS. WEST OF THE FRONT...SURFACE WINDS HAVE INCREASED
MARKEDLY ACROSS SOUTHWEST KANSAS...ESPECIALLY IN THE GARDEN CITY TO
ULYSSES AREAS...WHERE OBSERVATIONS OF 32-35 KNOTS SUSTAINED ARE
COMING IN WITH SOME GUSTS IN THE 44-48 KNOT RANGE...WHICH WAS
GETTING CLOSE TO HIGH WIND WARNING CRITERIA. RESIDUAL SURFACE
MOISTURE WAS WRAPPING AROUND THE LOW ON THE WEST AND SOUTHWEST
SIDE...WITH IN THE UPPER 40S TO NEAR 50 FROM LA JUNTA EAST AND
SOUTHEAST TO MUCH OF SOUTHWEST KANSAS...DESPITE THE WEST WINDS.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 135 PM CDT FRI APR 27 2012
THE MAIN CHALLENGE WILL BE WHAT BECOMES OF ANY SURFACE-BASED
CONVECTION GENERATED OVER THE HIGHER ELEVATION OF SOUTHEAST COLORADO
WHERE SOME RESIDUAL MOISTURE RESIDES. JUST ABOUT ALL OF THE HIGH
RESOLUTION MODEL (BOTH CONVECTION-ALLOWING AND CONVECTIVE
PARAMETERIZATION MODELS) GENERATE SOME STORMS NEAR OR SOUTHEAST OF
THE PALMER DIVIDE AND MOVE IT SOUTHEAST TOWARD FAR SOUTHEAST
COLORADO/FAR SOUTHWEST KANSAS BY EARLY THIS EVENING. HAVE DECIDED
TO GO WITH SOME 20-30 POPS IN THE FAR SOUTHWEST COUNTIES THROUGH THE
MID EVENING HOURS TO ACCOUNT FOR THIS. AS FAR AS TEMPERATURES
GO...CLEARING SKIES SHOULD ALLOW TEMPERATURES TO FALL DOWN INTO THE
LOWER 40S ACROSS MUCH OF THE FORECAST AREA WEST AND NORTH OF A
LIBERAL TO DODGE CITY TO HAYS LINE...THANKS TO DIMINISHING NORTH
WINDS TO 7 KNOTS OR LESS FOR RADIATIONAL COOLING. ON SATURDAY...A
SMALL SURFACE HIGH WILL BE CENTERED OVER WESTERN KANSAS WITH
NORTHEAST SURFACE WINDS. 850MB TEMPERATURES OF +10 TO +13C ACROSS
SOUTHWEST KANSAS WILL SUPPORT HIGHS NEAR 70 FOR MOST OF THE AREA
UNDER CLEAR SKIES FOR THE MOST PART...AS THE NEW LARGER UPPER LOW
TAKING SHAPE OVER THE DAKOTAS WILL BE FAR ENOUGH AWAY TO PREVENT ANY
INFLUENCE ON HAZARDOUS SENSIBLE WEATHER ACROSS SOUTHWEST KANSAS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 350 PM CDT FRI APR 27 2012
AFTER THE STRONG UPPER-LEVEL TROUGH MENTIONED IN THE SHORT TERM
DISCUSSION PASSING THIS EVENING, THE ASSOCIATED COLD FRONT WILL PUSH
SOUTHEAST AND STALL OUT ACROSS SOUTHERN OKLAHOMA. HOWEVER,
UPPER-LEVEL TROUGHINESS WILL HANG BACK OVER THE ROCKIES THIS
WEEKEND, WITH AN ASSOCIATED JET STREAK ACROSS KANSAS. THUNDERSTORMS
WILL LIKELY DEVELOP ALONG THE FRONT SATURDAY NIGHT. BY SUNDAY SOME
OF THE MODELS MOVE THE FRONT BACK AS A WARM FRONT, TRIGGERING
THUNDERSTORMS ACROSS 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 MONDAY, THE ROCKIES TROUGH WILL LIFT NORTHEAST
INTO SOUTHERN CANADA. BUT SOUTHWEST KANSAS WILL STILL BE IN THE
ENTRANCE REGION OF THE ASSOCIATED EXITING JET STREAK. GIVEN THE
STRONG ZONAL COMPONENT TO THE MID LEVEL WINDS AND ADDITIONAL
UPPER-LEVEL TROUGHING ACROSS THE NORTHWEST UNITED STATES, LEE
TROUGHING AND WARM ADVECTION WILL DEVELOP. THIS WILL TEND TO BRING
THE HIGHER DEWPOINTS AND WARMER TEMPERATURES BACK INTO WESTERN
KANSAS. THUS, THUNDERSTORMS ARE POSSIBLE ALONG THE LEE TROUGH OR
DRYLINE.
BY TUESDAY AND WEDNESDAY, THE NEXT JET STREAK WILL BE MOVING ACROSS
ROCKIES AND NORTHERN 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. HOWEVER,
ANY THUNDERSTORMS WILL BE ISOLATED GIVEN THE POSITIONING OF THE
UPPER-LEVEL JET WELL TO THE NORTH. IT WILL BE WARMER BY THIS TIME,
WITH HIGHS IN THE 80S TO LOWER 90S AND LOWS IN THE 50S TO MID 60S.
THE HIGHEST MINIMUM TEMPERATURES, AS IS TYPICAL, WILL BE IN SOUTH
CENTRAL KANSAS WHERE DEWPOINTS WILL BE HIGHER.
A COLD FRONT IS PROGGED BY THE ECMWF/GEM/GFS TO SAG SOUTHWARD INTO
WESTERN KANSAS BY THURSDAY AS A SHORTWAVE TROUGH PASSES ACROSS THE
NORTHERN PLAINS. TEMPERATURES WILL BE VERY WARM WITH LOWS IN THE 50S
AND 60S AND HIGHS IN THE 80S AND 90S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 620 PM CDT FRI APR 27 2012
A COMPACT NEGATIVELY TILTED VORTMAX/500 HPA TROF IS MOVING ACROSS NC
KS THIS AFTERNOON. IN THE WAKE OF THIS DISTURBANCE, WRAP AROUND MOISTURE
IS OBSERVED ACROSS FAR E CO/FAR W KS. RUC FRCST SOUNDINGS ALSO SHOW
COLD AIR ADVECTION WITHIN THE 875 HPA-700 HPA LAYER W/ SPC MESOANALYSIS
INDICATING SBCAPE OF 500-1000 J/KG ACROSS WC KS/E CO. THIS HAS RESULTED
IN THE DEVELOPMENT OF CONVECTION. BELIEVE THIS ACTIVITY WILL REMAIN
ISOLATED ENOUGH TO NOT INCLUDE IN TAFS. IMMEDIATE CONCERN IS STRONG
NW WINDS THAT WILL SUBSIDE NEAR SUNSET. VFR CIGS WILL PREVAIL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 47 69 46 64 / 10 0 40 40
GCK 43 68 45 63 / 20 0 40 40
EHA 43 68 45 65 / 20 0 40 40
LBL 44 69 46 64 / 20 0 40 40
HYS 44 68 44 64 / 10 0 30 40
P28 53 71 50 65 / 10 0 60 60
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
KSZ043>045-061>065-074>080-085>088.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
358 PM CDT THU APR 26 2012
...UPDATED FOR LONG TERM DISCUSSION...
.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 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 115 PM CDT THU APR 26 2012
STRONG TO SEVERE STORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHWEST
KANSAS TONIGHT AND AFFECT DDC, GCK, AND HYS TERMINALS. TIMING OF
CONVECTION IS STILL A SUBSTANTIAL CHALLENGE...BUT THE BEST THINKING
AT THIS TIME IS CONVECTION AFFECTING DDC AND GCK TERMINALS FROM
ROUGHLY 06-10Z AND HYS LATER ON FROM ROUGHLY 10-14Z. THERE MAY EVEN
BE MORE THAN ONE ROUND OF STORMS, BUT THIS CANNOT BE FORECAST IN THE
TAF AT THIS TIME. THERE IS ALSO EXPECTED TO BE A 2 TO 4 HOUR PERIOD
OF SOME LOW CEILINGS IN THE IFR CATEGORY AS LOW LEVEL MOISTURE MOVES
NORTHWARD DURING THE 09-12Z TIME FRAME. DRY AIR WILL THEN MOVE
QUICKLY NORTHEAST AFTER DAYBREAK FRIDAY WITH FLIGHT CATEGORY BACK TO
VFR DURING THE 13-15Z TIME FRAME AT GCK/DDC...BUT NOT UNTIL EARLY
AFTERNOON UP AT HYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 78 45 69 / 80 70 0 0
GCK 56 77 43 68 / 80 40 0 0
EHA 53 77 43 68 / 70 10 0 0
LBL 56 79 45 69 / 70 20 0 0
HYS 61 74 43 67 / 70 80 0 0
P28 64 83 51 71 / 40 50 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ TO 8 PM CDT /7 PM MDT/
FRIDAY FOR KSZ043>045-061>065-075>080-086>088.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS TOPEKA KS
308 PM CDT THU APR 26 2012
.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...
WITH SFC RIDGING AND RELATIVELY DRY LOW LEVELS OF THE TROPOSPHERE...
EXPECT VFR CONDITIONS TO PREVAIL THROUGH THIS EVENING UNTIL
CYCLOGENESIS INCREASES OVER THE CENTRAL HIGH PLAINS. THE DEEPENING
SFC LOW IS EXPECTED TO INCREASE THE PRESSURE GRADIENT AND CAUSE
MOISTURE TO BE LIFTED UP OVER THE SHALLOW RIDGE OF HIGH PRESSURE.
BECAUSE OF THIS HAVE INTRODUCED SOME MVFR CIGS TOWARDS DAY BREAK.
ADDITIONALLY INCREASING FORCING FROM THE UPPER LEVEL WAVE
APPROACHING FROM THE WEST SHOULD ALLOW PRECIP TO DEVELOP. THINK THE
WARM FRONT WILL REMAIN TO THE SOUTHWEST OF THE TERMINALS THROUGH 18Z
FRI. SO WITH SOME INHIBITION TO CONVECTION ROOTED IN THE BOUNDARY
LAYER...ONLY HAVE A VCTS FOR FRIDAY MORNING SINCE IT IS UNCERTAIN
WHERE ELEVATED CONVECTION MAY GO.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
252 PM CDT THU APR 26 2012
...UPDATED SHORT TERM SECTION DISCUSSING SEVERE WEATHER TONIGHT...
.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 THROUGH WEDNESDAY)
ISSUED AT 334 AM CDT THU APR 26 2012
ON FRIDAY MORNING THE NEGATIVELY TILTED SHORTWAVE TROUGH WILL BE
MOVING FROM THE CENTRAL PLAINS AND INTO THE MISSOURI VALLEY BY
FRIDAY EVENING. ONGOING THUNDERSTORMS SHOULD CONTINUE NORTH OF A
LINE FROM SCOTT CITY TO NEAR DODGE CITY AND MEDICINE LODGE WITH THE
DRYLINE AND COLD FRONT IN THE EARLY MORNING THEN ENDING AROUND HAYS
IN THE AFTERNOON. HIGH TEMPERATURES FOR FRIDAY WILL RANGE FROM THE
LOW TO MID 70S NORTH FA TO THE MID 80S SOUTHEAST AROUND MEDICINE
LODGE.
FOR SATURDAY A BROAD UPPER LEVEL TROUGH WILL SLOWLY MOVE EAST INTO
THE GREAT PLAINS WITH DRY WEATHER EXPECTED INTO KANSAS. SURFACE HIGH
PRESSURE WILL DOMINATE THE CENTRAL PLAINS. MORNING LOWS WILL RANGE
IN THE MID 40S NORTH TO THE LOW 50S SOUTH. HIGHS WILL BE MUCH COOLER
AND ONLY IN THE MID 60S TO AROUND 70. SOME HIGH LEVEL MOISTURE
STREAMING ACROSS THE ROCKIES COULD CREATE ABUNDANT CIRRUS CLOUDS
WITH LIMITED INSOLATION.
ON SUNDAY THE UPPER LEVEL TROUGH WILL MOVE NORTHEASTWARD INTO THE
NORTHERN HIGH PLAINS AND DOWN ACROSS THE CENTRAL PLAINS. MOISTURE
WILL RETURN AHEAD OF THE UPPER TROUGH AS UPSLOPE WINDS DEVELOP AS
PRESSURES FALL IN THE LEE OF THE ROCKIES. COULD HAVE LOTS OF STRATUS
AND FOG IN THE MORNING WITH LOWS IN THE MID TO UPPER 40S. THE CLOUDY
TO MOSTLY CLOUDY SKIES COULD LINGER INTO THE AFTERNOON WITH HIGHS
ONLY IN THE 60S. WILL KEEP A 20 TO 40 POP GOING FOR SHOWERS AND
ISOLATED THUNDER WITH THE UPPER SYSTEM AND ELEVATED CAPE INTO SUNDAY
NIGHT. RAINFALL AMOUNTS COULD RANGE FROM 1/4 OF AN INCH TO AROUND AN
INCH IF THE GFS VERIFIES. THE NEW ECMWF HAS LESS QPF.
ON MONDAY ANOTHER UPPER LEVEL SHORTWAVE TROUGH MOVES INTO THE
NORTHERN AND CENTRAL PLAINS WITH SURFACE MOISTURE CONTINUING AHEAD
OF A LEE LOW AS A WARM FRONT TRIES TO RETURN NORTH FROM TEXAS. WILL
KEEP A 20 TO 40 POP WEST TO EAST WITH THE BEST MOISTURE EAST. MORE
MAINLY ELEVATED SHOWERS AND THUNDERSTORMS COULD DEVELOP NEAR AND
NORTH OF THE WARM FRONT. MORNING LOWS WILL BE MILD AND IN THE 50S
WITH AFTERNOON HIGHS NEAR 80 IN THE SOUTHWEST WITH THE WARM FRONT
AND UPPER 60S FAR NORTHEAST AROUND HAYS. SHOWERS AND THUNDERSTORMS
COULD LINGER INTO TUESDAY AND TUESDAY NIGHT MAINLY IN THE EAST.
HIGHS ON TUESDAY SHOULD BE IN THE LOW TO MID 80S SOUTHWEST AND NEAR
80 IN THE NORTH AND EAST FA.
BY WEDNESDAY ANOTHER IN A SERIES OF UPPER LEVEL TROUGHS WILL MOVE
ACROSS THE PLAINS WITH THE BEST MOISTURE SCOURED OUT INTO EASTERN
KANSAS. STILL COULD HAVE MORE THUNDERSTORMS AGAIN IN THE EAST IF
THE ECMWF IS CORRECT. LOWS ON WEDNESDAY MORNING WILL BE MILD AND IN
THE 50S AND HIGHS AROUND 80.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 115 PM CDT THU APR 26 2012
STRONG TO SEVERE STORMS ARE EXPECTED TO DEVELOP ACROSS SOUTHWEST
KANSAS TONIGHT AND AFFECT DDC, GCK, AND HYS TERMINALS. TIMING OF
CONVECTION IS STILL A SUBSTANTIAL CHALLENGE...BUT THE BEST THINKING
AT THIS TIME IS CONVECTION AFFECTING DDC AND GCK TERMINALS FROM
ROUGHLY 06-10Z AND HYS LATER ON FROM ROUGHLY 10-14Z. THERE MAY EVEN
BE MORE THAN ONE ROUND OF STORMS, BUT THIS CANNOT BE FORECAST IN THE
TAF AT THIS TIME. THERE IS ALSO EXPECTED TO BE A 2 TO 4 HOUR PERIOD
OF SOME LOW CEILINGS IN THE IFR CATEGORY AS LOW LEVEL MOISTURE MOVES
NORTHWARD DURING THE 09-12Z TIME FRAME. DRY AIR WILL THEN MOVE
QUICKLY NORTHEAST AFTER DAYBREAK FRIDAY WITH FLIGHT CATEGORY BACK TO
VFR DURING THE 13-15Z TIME FRAME AT GCK/DDC...BUT NOT UNTIL EARLY
AFTERNOON UP AT HYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 82 45 69 / 50 10 0 0
GCK 56 78 43 68 / 50 10 0 0
EHA 53 80 43 68 / 30 10 0 0
LBL 56 82 45 69 / 30 10 0 0
HYS 61 74 43 67 / 70 70 0 0
P28 64 85 51 71 / 40 30 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ TO 8 PM CDT /7 PM MDT/
FRIDAY FOR KSZ043>045-061>065-075>080-086>088.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...KRUSE
AVIATION...UMSCHEID
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1057 PM EDT FRI APR 27 2012
.Forecast Update...
Issued at 1057 PM EDT Apr 27 2012
Isentropic lift is currently generating some light showers across
the Ohio Valley. However, with dry air at low levels, only a few
isolated sprinkles will be possible. This will occur across mainly
the Bluegrass region for the next few hours. Then expect a dry
period before the next upper wave approaches from the west. This
should begin to spread precip into the Ohio Valley around the 08-09Z
time frame. The HRRR had a good handle on the afternoon/evening
precip in our south, and also depicts scattered showers mainly along
and north of the Ohio River arriving in the pre-dawn hours. Have
adjusted PoPs accordingly. Think the chance of thunder is very
minimal overnight, so have pulled it from the products. Updated
products have been issued.
Update issued at 645 PM EDT Apr 27 2012
Band of showers and thunderstorms are entering our western CWA. Have
increased PoPs across the west, with emphasis on our southwest.
Overall precip is diminishing and starting to dive southeast. Expect
scattered showers and thunderstorms across our southwest, with rain
showers and isolated thunder more likely further north. Then,
chances seem to become less as the precip shield behind this band
has diminished somewhat. Tried to reflect this over the next few
hours with the hourly grids. Updated products have been issued.
.Short Term (Tonight through Saturday night)...
Issued at 300 PM EDT Apr 27 2012
Low pressure over Kansas this evening will progress east into
northern Missouri by morning, lifting a warm front northward across
Tennessee. Showers and thunderstorms were occurring from the Plains
to the Ozarks ahead of this system Friday afternoon, and will move
to the northeast tonight. It appears that the bulk of the rain will
stay north of the Ohio River, where there will be stronger forcing
and deeper moisture. The best chance of showers in the LMK CWA will
be between 4am and 9am along and north of the river.
During the day Saturday the low will advance to the Louisville area
by evening and will pull its warm front up to about Interstate 64.
We should see a break in the precipitation after the morning
activity moves out and before any redevelopment occurs later in the
day. There is some question concerning storms tomorrow. Southern
Kentucky looks to stay well capped, and northern sections of the CWA
will stay capped through much of the day, until late in the
afternoon at Louisville and early evening at Lexington. Winds aloft
aren/t very strong, and the capping plus widespread leftover clouds
in the north behind the departing morning showers may hinder
destabilization. Deep moisture is somewhat lacking as well. At any
rate, it should take until late afternoon before storms can start to
reform. Hail looks to be the main threat from any storms, with wet
bulb zero heights around nine or ten thousand feet.
Shower and thunderstorm chances will continue into the evening hours
before diminishing late Saturday night. The warm front will likely
remain in the general vicinity.
Lows tonight should range from the upper 40s northeast to middle 50s
southwest. Highs tomorrow will be tricky with the front draped
right across the area...right now we`re going for lower 70s in the
north and lower 80s near the Tennessee border. Lows Saturday night
will be in the 50s.
.Long Term (Sunday through Friday)...
Issued at 300 PM EDT Apr 27 2012
By Monday night a ridge of high pressure will park itself over the
southeast United States, extending east into the Atlantic. This
will cause a persistent northerly flow of warm, moist air from the
Gulf of Mexico into the Tennessee and Ohio Valleys. Various
difficult-to-time disturbances both at the surface and aloft will
cross from the Plains into the northeastern U.S. and interact with
the moisture throughout the week and into the weekend, resulting in
a broken record forecast of scattered showers and storms throughout
the period. The week won`t be a washout...just occasional waves
of scattered convection.
The work week will be warm with highs in the 70s/80s Monday/Tuesday
and securely into the 80s from Wednesday into the weekend.
&&
.Aviation (00Z TAF Issuance)...
Updated at 730 PM EDT Apr 27 2012
Current band of showers and thunderstorms is around BWG at this
time. These should be in the area for the next hour or so. Will back
off on precip wording for later this evening/overnight as better
rain chances shift north. Otherwise, mid and high level cloudiness
will continue to spread across the region, with cigs lowering
through the forecast period. The Plains low is still on schedule to
move east to around SDF by Saturday evening, with the warm front
near the I-64 corridor. Expect another round of showers and
thunderstorms to move ahead of this system through Indiana late
tonight into Saturday morning, but the bulk of the precip appears to
stay north of the TAF sites with SDF remaining on the edge of the
rain showers. Afternoon redevelopment will be possible as the low
pressure approaches, but believe the best chance would be along the
front near the end of the SDF TAF. So, will include VCSH at this
time.
Easterly winds will slowly veer through the TAF period, becoming
southeasterly in the morning, then breezy west-southwest in the
afternoon. By the end of the SDF period, the warm front should be in
the area or slip just south, which would allow winds to become
northwesterly.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........MJP
Short Term.......13
Long Term........13
Aviation.........MJP
AREA FORECAST DISCUSSION
NWS JACKSON KY
1053 PM EDT FRI APR 27 2012
.UPDATE...
ISSUED AT 1053 PM EDT FRI APR 27 2012
THE WARM FRONT REMAINS POISED ACROSS THE TENNESSEE VALLEY. THIS WILL
BEGIN TO LIFT TO NORTH BETWEEN 06 AND 12Z...LIKELY STALLING ACROSS
THE MIDDLE OF EASTERN KENTUCKY DURING THE DAY ON SATURDAY. THE LATEST
00Z NAM IS SHOWING A LITTLE BIT OF PRECIPITATION ACROSS THE AREA
BETWEEN 09 AND 12Z...MOST LIKELY IN RESPONSE TO SOME ISENTROPIC LIFT
IN THE 700-800 MB LAYER ONCE AGAIN. THERE IS A LITTLE ELEVATED
INSTABILITY ASSOCIATED WITH THIS...HOWEVER THE SOUNDINGS LOOK
MARGINAL FOR THUNDER...SO WILL CONTINUE TO ONLY MENTION A FEW
SHOWERS. ONCE THIS FORCING RELAXES DURING SATURDAY MORNING...THERE
SHOULD BE A PRETTY GOOD LULL IN THE ACTIVITY UNTIL THE AFTERNOON
HOURS AS WE REMAIN CAPPED. AS SUCH...ADJUSTED SOME OF THE POPS DOWN A
BIT THROUGH SATURDAY MORNING...BEFORE RAMPING BACK UP DURING THE
AFTERNOON...AS A WEAK SHORT WAVE TROUGH APPROACHES OVER TOP THE
LINGERING SURFACE BOUNDARY. FORECAST LOWS RANGING FROM THE LOWER TO
MIDDLE 40S IN THE MORE SHELTERED VALLEYS IN FAR NORTHEASTERN
KENTUCKY...TO THE LOWER TO MIDDLE 50S WEST OF I-75 LOOK ON
TARGET...AND HAVE ONLY MADE SOME MINOR DIURNAL ADJUSTMENTS ACCORDING
TO THE LATEST OBSERVATIONS.
UPDATE ISSUED AT 753 PM EDT FRI APR 27 2012
AN AREA OF WEAKENING CONVECTION IS CURRENTLY MOVING ACROSS SOUTH
CENTRAL KENTUCKY. THIS APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC
LIFT IN THE 800-700 MB LAYER. THE HRRR MODEL WAS PICKING UP ON THIS
ACTIVITY FAIRLY WELL...DIMINISHING IT AS IT MOVES INTO EASTERN
KENTUCKY. LOCATIONS WEST OF I-75 MAY SEE A FEW SPRINKLES OUT OF
THIS...HOWEVER WITH SUCH DRY LOW LEVEL AIR IN PLACE...WOULD NOT
EXPECT ANYTHING MORE THAN THAT. FRESHENED UP THE REST OF THE HOURLY
DATA AND TRIED TO ACCOUNT FOR A LITTLE SHARPER TEMPERATURE DROP IN
THE NORTHEAST VALLEYS WITH AT LEAST MOSTLY CLEAR TO PARTLY CLOUDY
SKIES EXPECTED INTO EARLY THIS EVENING. WILL REASSESS THE FORECAST
LOWS AS WELL AS IF ANY CONVECTION CAN FIRE UP TOWARDS DAWN
ASSOCIATED WITH THE RETURN OF THE WARM FRONT A BIT LATER ON.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 307 PM EDT FRI APR 27 2012
SFC ANALYSIS AT 18Z SHOWS YESTERDAY/S COLD FRONT TEMPORARILY RESIDES
ACROSS THE DEEP SOUTH AS A QUASI STATIONARY BOUNDARY...WITH AN
INVERTED TROF ALONG THE FRONT RANGE OF THE ROCKIES. THESE TWO
FEATURES WILL BECOME THE MAIN PLAYERS FOR OUR WX OVER THE SHORT TERM
AS THE FRONT BEGINS TO LIFT BACK TO THE NORTH TONIGHT IN RESPONSE TO
AN AREA OF LOW PRESSURE EJECTING OUT OF THE ROCKIES AND INTO THE
CENTRAL PLAINS. TEMPS TONIGHT WILL BE SOMEWHAT CHALLENGING WITH
ANTICIPATED CLOUD COVER RETURNING FROM THE SOUTH ALONG WITH WARMER
AIR ADVECTING INTO THE REGION...AND UPPER 40S IN THE NORTH TO LOW 50S
IN THE SOUTH WILL NOT QUITE TELL THE WHOLE STORY AS LOWS COULD BE
REALIZED EARLY BEFORE TEMPS LEVEL OFF OR EVEN BEGIN TO CREEP BACK UP
AFTER MIDNIGHT...ESPECIALLY IN THE SOUTH.
12Z MODELS CONTINUE TO DEPICT DECENT ISENTROPIC ASCENT ALONG THE
BOUNDARY AS IT PUSHES NORTH INTO THE REGION LATER TONIGHT...HOWEVER
THE MODELS ARE NOT BEING VERY GENEROUS WITH THE DEEPER MOISTURE. FCST
SOUNDINGS POINT TOWARDS A CONSIDERABLE DRY LAYER BETWEEN H9 AND H7
THRU MOST OF THE OVERNIGHT AND IF PUSH CAME TO SHOVE...CURRENT PROGS
WOULD NOT REALLY SUPPORT ANY PRECIP THRU 12Z BUT WITH A RETURN FLOW
REGIME COMMENCING AND A LEGITIMATE BOUNDARY EXPECTED TO BEGIN NOSING
INTO THE AREA...WILL KEEP ISOLATED SHOWERS IN THE MIX FOR TONIGHT.
BETTER MID AND UPPER LEVEL DYNAMICS LOOK TO ARRIVE ON SATURDAY WITH A
MODEST 50 TO 60 MPH MID AND UPPER LEVEL JET OVERHEAD ALONG WITH A MID
LEVEL IMPULSE SCOOTING ALONG THE OHIO VALLEY AS THE WEAKENING SFC LOW
DRIFTS INTO THE MIDWEST...PULLING THE WARM FRONT FURTHER NORTH
TOWARDS...AND POSSIBLY ACROSS THE OHIO RIVER. PARTIALLY CLEARING
SKIES FROM SOUTH TO NORTH WILL LEAD TO INCREASING INSTABILITY THROUGH
THE LATE MORNING AND EARLY AFTERNOON AS TEMPS REBOUND INTO THE MID
AND UPPER 70S WITH DEW PTS MOISTENING INTO THE MID 50S. MODELS HAVE
BEEN CONSISTENTLY ADVERTISING ALL OF THE NECESSARY INGREDIENTS FOR
DMC WITH A POTENTIAL FOR SOME STRONG TO SEVERE TSTMS DURING THE LATE
AFTERNOON AND EVENING. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREATS WITH ANY STORMS ON SATURDAY AFTERNOON...AND SPC HAS A GOOD
HANDLE ON ALL OF THIS WITH MOST OF ERN KY HIGHLIGHTED IN THE DY2.
CONVECTION SHOULD BEGIN TO LOOSE SOME OF ITS TEETH OVERNIGHT WITH THE
LOSS OF DAYTIME HEATING...THOUGH THE POTENTIAL FOR OUTFLOW BOUNDARIES
LOITERING ABOUT THE AREA OVERNIGHT SHOULD BE ENOUGH TO WARRANT A
THREAT FOR SCATTERED SHOWERS ALONG WITH ISOLATED RUMBLES THROUGH THE
REMAINDER OF THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 PM EDT FRI APR 27 2012
ON SUNDAY THE UPPER AIR STARTS OUT IN AN OMEGA LIKE PATTERN WITH AN
UPPER LOWS OVER THE WESTERN DAKOTAS AND NORTHEAST CANADA WITH A RIDE
EXTENDING FROM A HIGH OVER THE FLORIDA PANHANDLE EXTENDING NORTH
ACROSS INDIANA AND WISCONSIN AND THEN ENDING OVER NORTHERN MANITOBA.
THE PATTERN THEN TRIES TO MORPH INTO A ZONAL PATTERN. THE BOTTOM
LINE IS THAT THE STORM TRACK STAYS OVER OR NEAR THE AREA THROUGH THE
PERIOD. SO CONFIDENCE IS FAIRLY HIGH THAT THIS WILL BE A GENERALLY
ACTIVE WEATHER PATTERN WITH FREQUENT FRONTS AND TROUGHS MOVING
ACROSS THE AREA. THE HARD PART IS THE TIMING AND THIS IS WHERE THE
MODELS DIVERGE. IN ZONAL PATTERNS...SMALL SPEED DIFFERENCES CAN HAVE
GREAT DIFFERENCES IN TIMING.
IN GENERAL TRENDED THE MODEL BLEND TOWARD THE TIMING OF THE ECMWF.
WITH GREATER CONFIDENCE IN THE TIMING...THERE WOULD HAVE BEEN MORE
DRY PERIODS IN THE FORECAST...HOWEVER WITH THE TIMING
DIFFERENCES...SOME OF THE SYSTEMS TENDED TO BLUR TOGETHER. AFTER
SUNDAY...EASTERN KENTUCKY WILL BE IN THE WARM SECTOR AND
TEMPERATURES WILL STAY AT OR ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 753 PM EDT FRI APR 27 2012
EXPECT VFR CONDITIONS TO HOLD ON THROUGH AT LEAST DAWN...AS MAINLY
MID AND HIGH LEVEL CLOUDS ADVECT IN FROM THE WEST. A WARM FRONT WILL
THEN ENCROACH FROM THE SOUTHWEST TOWARDS DAWN...BRINGING IN LOWER
CLOUD COVER...ALTHOUGH STILL ABOVE 3K FEET. THERE MAY BE SOME
SCATTERED CONVECTION ASSOCIATED WITH THIS AS IT MOVES NORTH ACROSS
EASTERN KENTUCKY...HOWEVER WILL CONTINUE TO ONLY MENTION VCSH AT THIS
TIME. WINDS WILL SHIFT TO THE SOUTHWEST BEHIND THE WARM FRONT AND
BECOME GUSTY DURING THE DAY. EXPECT ADDITIONAL SCATTERED STRONGER
CONVECTION TO FIRE UP IN THE AFTERNOON...ESPECIALLY NORTH OF THE
MOUNTAIN PARKWAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...MB
LONG TERM....JJ
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS JACKSON KY
753 PM EDT FRI APR 27 2012
.UPDATE...
ISSUED AT 753 PM EDT FRI APR 27 2012
AN AREA OF WEAKENING CONVECTION IS CURRENTLY MOVING ACROSS SOUTH
CENTRAL KENTUCKY. THIS APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC
LIFT IN THE 800-700 MB LAYER. THE HRRR MODEL WAS PICKING UP ON THIS
ACTIVITY FAIRLY WELL...DIMINISHING IT AS IT MOVES INTO EASTERN
KENTUCKY. LOCATIONS WEST OF I-75 MAY SEE A FEW SPRINKLES OUT OF
THIS...HOWEVER WITH SUCH DRY LOW LEVEL AIR IN PLACE...WOULD NOT
EXPECT ANYTHING MORE THAN THAT. FRESHENED UP THE REST OF THE HOURLY
DATA AND TRIED TO ACCOUNT FOR A LITTLE SHARPER TEMPERATURE DROP IN
THE NORTHEAST VALLEYS WITH AT LEAST MOSTLY CLEAR TO PARTLY CLOUDY
SKIES EXPECTED INTO EARLY THIS EVENING. WILL REASSESS THE FORECAST
LOWS AS WELL AS IF ANY CONVECTION CAN FIRE UP TOWARDS DAWN
ASSOCIATED WITH THE RETURN OF THE WARM FRONT A BIT LATER ON.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 307 PM EDT FRI APR 27 2012
SFC ANALYSIS AT 18Z SHOWS YESTERDAY/S COLD FRONT TEMPORARILY RESIDES
ACROSS THE DEEP SOUTH AS A QUASI STATIONARY BOUNDARY...WITH AN
INVERTED TROF ALONG THE FRONT RANGE OF THE ROCKIES. THESE TWO
FEATURES WILL BECOME THE MAIN PLAYERS FOR OUR WX OVER THE SHORT TERM
AS THE FRONT BEGINS TO LIFT BACK TO THE NORTH TONIGHT IN RESPONSE TO
AN AREA OF LOW PRESSURE EJECTING OUT OF THE ROCKIES AND INTO THE
CENTRAL PLAINS. TEMPS TONIGHT WILL BE SOMEWHAT CHALLENGING WITH
ANTICIPATED CLOUD COVER RETURNING FROM THE SOUTH ALONG WITH WARMER
AIR ADVECTING INTO THE REGION...AND UPPER 40S IN THE NORTH TO LOW 50S
IN THE SOUTH WILL NOT QUITE TELL THE WHOLE STORY AS LOWS COULD BE
REALIZED EARLY BEFORE TEMPS LEVEL OFF OR EVEN BEGIN TO CREEP BACK UP
AFTER MIDNIGHT...ESPECIALLY IN THE SOUTH.
12Z MODELS CONTINUE TO DEPICT DECENT ISENTROPIC ASCENT ALONG THE
BOUNDARY AS IT PUSHES NORTH INTO THE REGION LATER TONIGHT...HOWEVER
THE MODELS ARE NOT BEING VERY GENEROUS WITH THE DEEPER MOISTURE. FCST
SOUNDINGS POINT TOWARDS A CONSIDERABLE DRY LAYER BETWEEN H9 AND H7
THRU MOST OF THE OVERNIGHT AND IF PUSH CAME TO SHOVE...CURRENT PROGS
WOULD NOT REALLY SUPPORT ANY PRECIP THRU 12Z BUT WITH A RETURN FLOW
REGIME COMMENCING AND A LEGITIMATE BOUNDARY EXPECTED TO BEGIN NOSING
INTO THE AREA...WILL KEEP ISOLATED SHOWERS IN THE MIX FOR TONIGHT.
BETTER MID AND UPPER LEVEL DYNAMICS LOOK TO ARRIVE ON SATURDAY WITH A
MODEST 50 TO 60 MPH MID AND UPPER LEVEL JET OVERHEAD ALONG WITH A MID
LEVEL IMPULSE SCOOTING ALONG THE OHIO VALLEY AS THE WEAKENING SFC LOW
DRIFTS INTO THE MIDWEST...PULLING THE WARM FRONT FURTHER NORTH
TOWARDS...AND POSSIBLY ACROSS THE OHIO RIVER. PARTIALLY CLEARING
SKIES FROM SOUTH TO NORTH WILL LEAD TO INCREASING INSTABILITY THROUGH
THE LATE MORNING AND EARLY AFTERNOON AS TEMPS REBOUND INTO THE MID
AND UPPER 70S WITH DEW PTS MOISTENING INTO THE MID 50S. MODELS HAVE
BEEN CONSISTENTLY ADVERTISING ALL OF THE NECESSARY INGREDIENTS FOR
DMC WITH A POTENTIAL FOR SOME STRONG TO SEVERE TSTMS DURING THE LATE
AFTERNOON AND EVENING. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREATS WITH ANY STORMS ON SATURDAY AFTERNOON...AND SPC HAS A GOOD
HANDLE ON ALL OF THIS WITH MOST OF ERN KY HIGHLIGHTED IN THE DY2.
CONVECTION SHOULD BEGIN TO LOOSE SOME OF ITS TEETH OVERNIGHT WITH THE
LOSS OF DAYTIME HEATING...THOUGH THE POTENTIAL FOR OUTFLOW BOUNDARIES
LOITERING ABOUT THE AREA OVERNIGHT SHOULD BE ENOUGH TO WARRANT A
THREAT FOR SCATTERED SHOWERS ALONG WITH ISOLATED RUMBLES THROUGH THE
REMAINDER OF THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 PM EDT FRI APR 27 2012
ON SUNDAY THE UPPER AIR STARTS OUT IN AN OMEGA LIKE PATTERN WITH AN
UPPER LOWS OVER THE WESTERN DAKOTAS AND NORTHEAST CANADA WITH A RIDE
EXTENDING FROM A HIGH OVER THE FLORIDA PANHANDLE EXTENDING NORTH
ACROSS INDIANA AND WISCONSIN AND THEN ENDING OVER NORTHERN MANITOBA.
THE PATTERN THEN TRIES TO MORPH INTO A ZONAL PATTERN. THE BOTTOM
LINE IS THAT THE STORM TRACK STAYS OVER OR NEAR THE AREA THROUGH THE
PERIOD. SO CONFIDENCE IS FAIRLY HIGH THAT THIS WILL BE A GENERALLY
ACTIVE WEATHER PATTERN WITH FREQUENT FRONTS AND TROUGHS MOVING
ACROSS THE AREA. THE HARD PART IS THE TIMING AND THIS IS WHERE THE
MODELS DIVERGE. IN ZONAL PATTERNS...SMALL SPEED DIFFERENCES CAN HAVE
GREAT DIFFERENCES IN TIMING.
IN GENERAL TRENDED THE MODEL BLEND TOWARD THE TIMING OF THE ECMWF.
WITH GREATER CONFIDENCE IN THE TIMING...THERE WOULD HAVE BEEN MORE
DRY PERIODS IN THE FORECAST...HOWEVER WITH THE TIMING
DIFFERENCES...SOME OF THE SYSTEMS TENDED TO BLUR TOGETHER. AFTER
SUNDAY...EASTERN KENTUCKY WILL BE IN THE WARM SECTOR AND
TEMPERATURES WILL STAY AT OR ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 753 PM EDT FRI APR 27 2012
EXPECT VFR CONDITIONS TO HOLD ON THROUGH AT LEAST DAWN...AS MAINLY
MID AND HIGH LEVEL CLOUDS ADVECT IN FROM THE WEST. A WARM FRONT WILL
THEN ENCROACH FROM THE SOUTHWEST TOWARDS DAWN...BRINGING IN LOWER
CLOUD COVER...ALTHOUGH STILL ABOVE 3K FEET. THERE MAY BE SOME
SCATTERED CONVECTION ASSOCIATED WITH THIS AS IT MOVES NORTH ACROSS
EASTERN KENTUCKY...HOWEVER WILL CONTINUE TO ONLY MENTION VCSH AT THIS
TIME. WINDS WILL SHIFT TO THE SOUTHWEST BEHIND THE WARM FRONT AND
BECOME GUSTY DURING THE DAY. EXPECT ADDITIONAL SCATTERED STRONGER
CONVECTION TO FIRE UP IN THE AFTERNOON...ESPECIALLY NORTH OF THE
MOUNTAIN PARKWAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...MB
LONG TERM....JJ
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
100 PM EDT THU APR 26 2012
.Forecast Update...
Issued at 1000 AM EDT Apr 26 2012
Today`s forecast challenge will be to see if another round of
thunderstorms fires up out ahead of the slow eastbound cold front
currently draped over eastern Kentucky. As the pre-dawn convection
continues to move out over the Appalachians, a stable atmosphere
took over central Kentucky and southern Indiana in its wake.
However, mesoscale models are indicating a refire of the convection
over the eastern portions of the forecast area, out ahead of that
cold front. This is due to continued diurnal heating and
southwesterly flow allowing for warming at the surface and for CIN
to diminish. The RUC shows SBCAPE values reaching up to 2000-2500
J/kg with no cap to keep it contained. Bottom line - going to have
to monitor this closely as the moisture seems to be the big question
right now. Model soundings as well as current WV sat imagery is
indicating dry air aloft pushing into the region.
Issued at 650 AM EDT Apr 26 2012
Have trimmed back the Severe Thunderstorm Watch some more this
morning. Removed all the counties except for the far southeastern
CWA where we have seen some renewed convection in the wake of the
stronger line. These storms will move out of the area during the
next hour. Beyond this morning, we will continue the mention for
some shower/thunderstorms over the eastern portion of the forecast
area through the afternoon hours.
Issued at 600 AM EDT Apr 26 2012
The strongest thunderstorms this morning continue to move south and
east across south central Kentucky. Have cancelled a large portion
of the watch this morning. Have kept the watch out over the
Bluegrass as there are a few stronger storms just to the north of
the forecast area. However, any severe weather should be isolated at
best.
.Short Term (Today through Friday)...
Issued at 350 AM EDT Apr 26 2012
The immediate concern this morning is the strong to severe
thunderstorms moving into the northwestern portion of the forecast
area. The isolated earlier storms have congealed into a larger
bowing MCS. Relatively warm temperatures and a strong shortwave have
contributed to the enhancement of this system. These storms are
expected to continue to remain strong as they track east across the
forecast area. We have therefore expanded the Severe Thunderstorm
Watch across most of the forecast area this morning. This watch goes
through 13Z, with most of the storms expected to be exiting to the
east by this time. Large hail will still be a concern with these
storms. However, the wind threat is increasing as a bowing line
develops and winds may become the main concern as the system moves
east.
For the rest of the day, rain chances will rapidly decrease. We may
have some lingering showers or thunderstorms across east central
Kentucky through the afternoon hours. There is a bit of uncertainty
however as the atmosphere should be fairly worked over in the wake
of this morning`s convection. Winds will shift this afternoon as the
cold front moves through. Winds are expected to become gusty ahead
of and behind this front. Gusts of 20-25 mph can be expected through
the late morning and afternoon hours. Highs today will be in the mid
70s north to the upper 70s in the south.
We will dry out tonight as the cold front sinks south of the area.
Skies will become partly cloudy to mostly clear with temperatures
dropping into the lower 40s in the north to the lower 50s in the
south. For Friday, the front to the south of the region will begin
to move back to the north as a warm front. Ahead of this front,
clouds will overspread the area. We should remain dry through mid
day. Showers and thunderstorms will then begin to move in from the
southwest. Think that coverage in the afternoon will be fairly
limited, so have reduced pops for tomorrow into the low chance range.
.Long Term (Friday Night through Wednesday)...
Issued at 251 AM EDT Apr 26 2012
Friday Night through Sunday Night...
Combination and of deterministic and ensemble guidance continues to
show a bit of spread throughout the long term forecast period. In
general, this will result in lower than normal forecast confidence.
Upper air pattern over the eastern third of the US will remain
generally zonal in nature with multiple short waves moving through
within the mean flow. So we`ll likely see heights rising and
lowering during the period with chances of precipitation occurring
as each wave passes through.
Previous forecast still looks fairly good compared to this evening`s
model runs. Stalled out frontal boundary to the south will likely
lift back northward as a warm front Friday evening as an area of low
pressure moves out of the Plains and into the upper Midwest. Just
how far north this front will lift northward on Saturday is still
quite questionable. This will lead to a large gradient of
temperatures across the region. We could see as much as a 15-20
degree gradient from south to north with highs in the lower 60s in
the north and readings in the upper 70s to the lower 80s in the
south. The front looks to sag back south of the area on Sunday
resulting a slightly drier forecast for now. Highs Sunday will
range from the lower 60s in the north tot he upper 60s to around 70
in the south...with overnight lows dropping into the upper 40s to
the lower 50s.
Monday through Wednesday...
Did not make many changes through this period given the wide spreads
in both the deterministic and ensemble guidance. The Ohio Valley
looks to remain in a baroclinic zone through the period as a surface
frontal boundary remains near the area. This boundary will start
off to the south of the area at the beginning of the period and
gradually lift northward once again. As multiple mid-level waves
aloft scoot past, they will likely result in off and showers and
storms. The predictability of the timing of these waves is quite
low...thus plan on leaving low chance PoPs in the forecast
throughout the period for now. It does appear that the front will
likely lift north of the Ohio Valley toward the end of the period
resulting in drier and warmer conditions as we head toward the end
of the workweek. Highs Mon/Tue should warm into the 70s with upper
70s to the lower 80s returning by Wednesday. Overnight lows will
generally be in the 50-60s.
&&
.Aviation (18Z TAF Issuance)...
Updated at 100 PM EDT Apr 26 2012
A CU field has been growing over the last few hours, causing most
area terminals to go MVFR. This cloud cover is expected to continue
to grow in coverage out ahead of an approaching cold front,
currently running along the Ohio River and out toward southwestern
Kentucky. A possibility exists for these clouds to grow into
thunderstorms later this afternoon into the early evening hours as
the atmosphere continues to destabilize under a warm, moist air
mass. Aviation interests in southern Indiana should be in the clear
but chances increase traveling southward, especially along the
Tennessee border. Once the sun sets and the cold front passes
through, VFR conditions can be anticipated through early tomorrow
afternoon. There will be another increased chance for thunderstorms
to develop again near the Tennessee border by later in the day on
Friday. The only other concern for the rest of today would be the
increasing winds/gusts as they shift from out of the southwest to
the northwest after the frontal passage.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........LG
Short Term.......EER
Long Term........MJ
Aviation.........LG
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1005 AM EDT THU APR 26 2012
.Forecast Update...
Issued at 1000 AM EDT Apr 26 2012
Today`s forecast challenge will be to see if another round of
thunderstorms fires up out ahead of the slow eastbound cold front
currently draped over eastern Kentucky. As the pre-dawn convection
continues to move out over the Appalachians, a stable atmosphere
took over central Kentucky and southern Indiana in its wake.
However, mesoscale models are indicating a refire of the convection
over the eastern portions of the forecast area, out ahead of that
cold front. This is due to continued diurnal heating and
southwesterly flow allowing for warming at the surface and for CIN
to diminish. The RUC shows SBCAPE values reaching up to 2000-2500
J/kg with no cap to keep it contained. Bottom line - going to have
to monitor this closely as the moisture seems to be the big question
right now. Model soundings as well as current WV sat imagery is
indicating dry air aloft pushing into the region.
Issued at 650 AM EDT Apr 26 2012
Have trimmed back the Severe Thunderstorm Watch some more this
morning. Removed all the counties except for the far southeastern
CWA where we have seen some renewed convection in the wake of the
stronger line. These storms will move out of the area during the
next hour. Beyond this morning, we will continue the mention for
some shower/thunderstorms over the eastern portion of the forecast
area through the afternoon hours.
Issued at 600 AM EDT Apr 26 2012
The strongest thunderstorms this morning continue to move south and
east across south central Kentucky. Have cancelled a large portion
of the watch this morning. Have kept the watch out over the
Bluegrass as there are a few stronger storms just to the north of
the forecast area. However, any severe weather should be isolated at
best.
.Short Term (Today through Friday)...
Issued at 350 AM EDT Apr 26 2012
The immediate concern this morning is the strong to severe
thunderstorms moving into the northwestern portion of the forecast
area. The isolated earlier storms have congealed into a larger
bowing MCS. Relatively warm temperatures and a strong shortwave have
contributed to the enhancement of this system. These storms are
expected to continue to remain strong as they track east across the
forecast area. We have therefore expanded the Severe Thunderstorm
Watch across most of the forecast area this morning. This watch goes
through 13Z, with most of the storms expected to be exiting to the
east by this time. Large hail will still be a concern with these
storms. However, the wind threat is increasing as a bowing line
develops and winds may become the main concern as the system moves
east.
For the rest of the day, rain chances will rapidly decrease. We may
have some lingering showers or thunderstorms across east central
Kentucky through the afternoon hours. There is a bit of uncertainty
however as the atmosphere should be fairly worked over in the wake
of this morning`s convection. Winds will shift this afternoon as the
cold front moves through. Winds are expected to become gusty ahead
of and behind this front. Gusts of 20-25 mph can be expected through
the late morning and afternoon hours. Highs today will be in the mid
70s north to the upper 70s in the south.
We will dry out tonight as the cold front sinks south of the area.
Skies will become partly cloudy to mostly clear with temperatures
dropping into the lower 40s in the north to the lower 50s in the
south. For Friday, the front to the south of the region will begin
to move back to the north as a warm front. Ahead of this front,
clouds will overspread the area. We should remain dry through mid
day. Showers and thunderstorms will then begin to move in from the
southwest. Think that coverage in the afternoon will be fairly
limited, so have reduced pops for tomorrow into the low chance range.
.Long Term (Friday Night through Wednesday)...
Issued at 251 AM EDT Apr 26 2012
Friday Night through Sunday Night...
Combination and of deterministic and ensemble guidance continues to
show a bit of spread throughout the long term forecast period. In
general, this will result in lower than normal forecast confidence.
Upper air pattern over the eastern third of the US will remain
generally zonal in nature with multiple short waves moving through
within the mean flow. So we`ll likely see heights rising and
lowering during the period with chances of precipitation occurring
as each wave passes through.
Previous forecast still looks fairly good compared to this evening`s
model runs. Stalled out frontal boundary to the south will likely
lift back northward as a warm front Friday evening as an area of low
pressure moves out of the Plains and into the upper Midwest. Just
how far north this front will lift northward on Saturday is still
quite questionable. This will lead to a large gradient of
temperatures across the region. We could see as much as a 15-20
degree gradient from south to north with highs in the lower 60s in
the north and readings in the upper 70s to the lower 80s in the
south. The front looks to sag back south of the area on Sunday
resulting a slightly drier forecast for now. Highs Sunday will
range from the lower 60s in the north tot he upper 60s to around 70
in the south...with overnight lows dropping into the upper 40s to
the lower 50s.
Monday through Wednesday...
Did not make many changes through this period given the wide spreads
in both the deterministic and ensemble guidance. The Ohio Valley
looks to remain in a baroclinic zone through the period as a surface
frontal boundary remains near the area. This boundary will start
off to the south of the area at the beginning of the period and
gradually lift northward once again. As multiple mid-level waves
aloft scoot past, they will likely result in off and showers and
storms. The predictability of the timing of these waves is quite
low...thus plan on leaving low chance PoPs in the forecast
throughout the period for now. It does appear that the front will
likely lift north of the Ohio Valley toward the end of the period
resulting in drier and warmer conditions as we head toward the end
of the workweek. Highs Mon/Tue should warm into the 70s with upper
70s to the lower 80s returning by Wednesday. Overnight lows will
generally be in the 50-60s.
&&
.Aviation (12Z TAF Issuance)...
Updated at 650 AM EDT Apr 26 2012
By 12Z the rain should be east of all the TAF sites. The models
continue to indicate a layer of moisture moving in this morning and
bringing MVFR ceilings. However, looking at satellite and upstream
observations, it is hard to find any indication of this. Will
therefore keep ceilings VFR at all the TAF sites. Winds will
increase this morning ahead of a cold front and wind shift this
afternoon. Sustained winds will be 12-15 knots with gusts to 20+
knots. Winds will initially be out of the SW, shifting to the NW by
late this afternoon. Skies should become mostly clear overnight with
winds dropping below 5 knots out of the north.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........LG
Short Term.......EER
Long Term........MJ
Aviation.........EER
AREA FORECAST DISCUSSION
NWS JACKSON KY
206 AM EDT THU APR 26 2012
.UPDATE...
ISSUED AT 206 AM EDT THU APR 26 2012
A WARM FRONT IS CURRENTLY ALIGNED ACROSS THE I-64 CORRIDOR...WITH
TRAINING CONVECTION ONGOING IN THE FAR NORTHEAST. AN INCREASING LOW
LEVEL JET WILL CONTINUE TO FEED MOISTURE ALONG THIS AXIS...WHICH
SHOULD SUSTAIN THIS ACTIVITY FOR THE NEXT FEW HOURS. CONVECTION FURTHER
SOUTHWEST HAS WANED. AS SUCH...HAVE REALLY TIGHTENED UP THE GRADIENT
OF POPS...REDUCING TO SLIGHT CHANCE FOR THE SOUTHWESTERN TWO
THIRDS...AND THEN CATEGORICAL ACROSS THE FAR NORTHEAST. LOW
TEMPERATURES HAVE LIKELY ALREADY BEEN ESTABLISHED AT MOST
LOCATIONS...AND EXPECT A STEADY OR SLOW RISE AT THIS POINT AS SOUTH
TO SOUTHWEST WINDS PICK UP. THE COLD FRONT LOOKS TO BE A LITTLE MORE
DELAYED TO PASS THROUGH THE AREA ON THURSDAY...WHICH WILL LIKELY
RESULT IN A BETTER CHANCE OF CONVECTION RE-FIRING DEPENDING UPON HOW
MUCH HEATING OCCURS. WILL WAIT FOR THE NEXT ISSUANCE PACKAGE TO
ADDRESS THIS CONCERN.
UPDATE ISSUED AT 1015 PM EDT WED APR 25 2012
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO CROSS ERN KY THIS
EVENING. STRONGEST STORMS PRODUCING SOME LIGHTNING AND RADAR
ESTIMATED TENTH OF AN INCH OF RAINFALL PER HOUR. STORMS ARE MOVING
EAST...100 DEG...AT NEARLY 40 PH SO NO STORM IS PRODUCING HEAVY RAIN
FOR ANY GIVEN LOCATION. PARENT LOW IS STILL LOCATED OVER WRN IL WITH
A WARM FRONT EXTENDING THRU ERN KY JUST NORTH OF LEX AND JUST SOUTH
OF JKL/PIKEVILLE. LOW PRESSURE SHOULD CONTINUE TO TRACK EAST WITH THE
WARM FRONT LIFTING TOWARD CVG AND PULLING MUCH OF THE PCPN NORTH OF
THE AREA. EXPECTING SRN KY TO SEE LITTLE ADDITIONAL PCPN WHILE NRN KY
WILL SEE ADDITIONAL ROUNDS OF SHRA THRU MUCH OF THE NIGHT. SPEED OF
THE STORMS WILL LIMIT TOTAL ACCUMULATION. GRIDS HAVE BEEN UPDATED
WITH EXPECTED POPS AND TEMPS. ZONES IN GOOD SHAPE WITH NO UPDATE
REQUIRED.
UPDATE ISSUED AT 757 PM EDT WED APR 25 2012
UPDATED FOR SHRA CROSSING ERN KY. ACTIVITY SHOULD BECOME RATHER
PERSISTENT FOR OUR NRN COUNTIES AND SHOULD SEE BREAKS IN THE ACTIVITY
FOR THE SWRN THIRD. TEMPS ON TRACK BUT HAVE TWEAKED SLIGHTLY TO
ACCOUNT FOR THE EARLIER ONSET OF PCPN. NOT SEEING ANY LIGHTNING AND
HAVE DOWNGRADED THE THUNDER CHANCES. MAY NEED TO TAKE THEM OUT
COMPLETELY LATER TONIGHT. WILL CONTINUE TO MONITOR.
UPDATE ISSUED AT 449 PM EDT WED APR 25 2012
TIMING OF CONVECTION APPROACHING FROM THE WEST AND FURTHER CONVECTION
ANTICIPATED LATER THIS EVENING AS WELL AS ASSOCIATED SKY COVER WAS
ADJUSTED BASED ON THE LATEST SAT AND RADAR TRENDS. OVERALL...THE 18Z
NAM HAS A DECENT HANDLE ON THE APPROACHING CONVECTION...BUT APPEARS
TO BE A BIT TOO SLOW. CONVECTION OVER THE NEXT 2 HOURS OR SO SHOULD
GENERALLY BE OVER THE SW CWA AND THEN PROBABLY BECOME FOCUS MORE TO
THE NE CLOSER TO THE WARM FRONT AND GREATER THETA AND DEWPOINT
GRADIENTS AS THE EVENING WEARS ON. CONVECTION THIS EVENING OR EARLY
TONIGHT IS STILL CAPABLE OF PRODUCING SOME HAIL OR STRONG WIND GUSTS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM EDT WED APR 25 2012
A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS
TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM.
AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER
MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW
FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF
THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES
UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE
SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT
EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA
COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA
GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL
KY.
OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT
EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING
OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED
TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO
REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH
VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION
THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER
UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP
SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON
THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN
VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD
THE CWA FROM LATE ON THU INTO THU NIGHT.
THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS
GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD
WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS
MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO
CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY
ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS
THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA.
SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA.
ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM
FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS
SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET
AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER
WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT
IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO
WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE
CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY
LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS
WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER
PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN
CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF
CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD
FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A
LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE
ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA.
IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD
GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD
OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON.
AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF
THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST
OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE
BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD
ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE
SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 PM EDT WED APR 25 2012
MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS
BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE
BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT
STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE
WEEKEND AND BEYOND.
THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR
SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY.
HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI
REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY
FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE
SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY
ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR
SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE
AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY
KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR
STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO
LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR
STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST
DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT
THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL
MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF
KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO
EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND
UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT
IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES
FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS
EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY
FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS
MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN
IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE
PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES
FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT
THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT
FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH
GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY.
A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH
THIS BOUNDARY AROUND OUR REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 206 AM EDT THU APR 26 2012
EXPECT VFR CONDITIONS TO HOLD ACROSS THE TAF SITES THROUGH DAWN...AS
CONVECTION HAS ORGANIZED ACROSS FAR NORTHEASTERN KENTUCKY. HAVE
INCLUDED A VCTS AT JKL...AS SOME SCATTERED SHOWERS AND THUNDERSTORMS
WILL BRUSH BY TO THE NORTH AND EAST THROUGH THE NIGHT. A PASSING COLD
FRONT WILL LIKELY RE-FIRE SOME CONVECTION ACROSS THE AREA DURING THE
DAY ON THURSDAY...HOWEVER WILL AWAIT FOR LATER GUIDANCE BEFORE TRYING
TO NAIL DOWN A BETTER WINDOW OF TIMING. FOR NOW...HAVE INCLUDED VCTS
AT ALL LOCATIONS. THE COLD FRONT WILL MOVE THROUGH LATE IN THE
AFTERNOON...WITH SOME MVFR OR LOWER POST-FRONTAL STRATOCU ON W TO NW
WINDS FOLLOWING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...JP
LONG TERM....KAS
AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
634 PM EDT THU APR 26 2012
.SYNOPSIS...
A COLD FRONT CROSSES THE AREA TONIGHT...THEN STALLS ACROSS THE
CAROLINAS FRIDAY. HIGH PRESSURE BUILDS IN FROM THE NORTH FRIDAY.
THE FRONT MOVES BACK NORTH AS A WARM FRONT SATURDAY MORNING...
THEN STALLS ACROSS THE MID ATLANTIC REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
FINAL BATCH OF PRECIP ASSOCIATED WITH MCV PUSHING OFFSHORE AS OF
22Z. EXPECT DRY CONDS IN MOST AREAS FOR THE REMAINDER OF THE
NIGHT. STILL INCLUDED SLGT CHC FOR SH/TSTM THRU MIDNGT...BULK OF
UPSTREAM ACTIVITY OVER EXTREME W VA IS NOT EXPECTED TO MAKE IT
INTO THE WAKEFIELD CWA THOUGH LATEST HRRR AND RUC13 SHOW THE
POSSIBILITY OF SOME PRECIP THIS EVNG. OTW...EXPECT DECREASING
CLOUDINESS AS COLD FRNT PUSHES THRU THE AREA LATE OVRNGT. LOWS
U40S-M50S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
BOUNDARY PROGGED TO STALL ACROSS THE CAROLINAS SATURDAY AS HIGH
PRESSURE BUILDS SOUTH ACROSS THE AREA. EXPECT A DRY DAY WITH A
N-NW WIND BECOMING BREEZY AT TIMES (15-25 MPH). LOADED THE MIXED
LAYERED DEW POINTS INTO THE GRIDS WHICH RESULTS IN RH VALUES BTWN
20-30 PERCENT DURING PEAK HEATING HOURS. GIVEN TODAYS RAINFALL...
EXPECT THE FUEL MOISTURES TO STAY ELEVATED. HIGHS 60-65 EASTERN
SHORE AREAS TO ARND 70 ACROSS THE PIEDMONT.
FORECAST CONTINUES TO BE RATHER CHALLENGING FOR THE REST OF THE
WEEKEND GIVEN THE DIFFERENT SOLUTIONS TO WHERE THE FRONTAL BOUNDARY
ACTUALLY ENDS UP. CLOUDS INCREASE FRI NIGHT AS BOUNDARY BEGINS TO
APPROACH FROM THE SOUTH. SOME WEAK H85 ADVECTION NOTED ACROSS
WESTERN COUNTIES SO KEPT SLGHT CHC POPS THERE AFTER MIDNITE. LOWS
MAINLY IN THE 40S...HOWEVER EXPECT ENOUGH CLR SKIES ACROSS THE
EASTERN SHORE FOR TEMPS TO DROP INTO THE M-U30S IVOF SBY WITH
STEADY TEMPS AFTER THAT.
LATEST SUITE OF GUIDANCE SUPPORTS AT LEAST A CHC POPS ALL AREAS SAT
AS BOUNDARY PROGGED TO STALL ACROSS THE REGION. TEMPS TRICKY AS A
POTENTIAL IN-SITU WEDGE SCANARIO SETTING UP ACROSS THE PIEDMONT
WHERE TEMPS MAY BE HARD PRESSED TO GET MUCH ABOVE 60...RANGING TO
BTWN 65-70 SOUTH OF THE FRONT. KEPT CHC POPS SAT NIGHT TAPERING
OFF TO SLGHT CHC ACROSS SOUTHERN AREAS. LOWS IN THE 40S TO L50S.
LINGERING MOISTURE RESULTS IN A M CLDY DAY SUNDAY. STILL CAN NOT
RULE OUT A SHOWER (20 POPS IN THE GRIDS ATTM). HIGHS M-U60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE UPPER LEVEL LOW THAT WILL IMPACT THE WEATHER OVER THE WEEKEND
MOVES OFF TO THE NORTHEAST BY SUNDAY NIGHT AND MONDAY. UPPER LEVEL
RIDGING WILL TAKE OVER TOWARD MID WEEK.
THE COLD FRONTAL BOUNDARY WILL EXTEND THROUGH THE CAROLINAS AT THE
BEGINNING OF THE LONG TERM PERIOD. STRONG SURFACE HIGH NORTH OF THE
GREAT LAKES WILL RIDGE SOUTH THROUGH THE MID ATLANTIC STATES AND
PUSH THE COLD FRONT INTO NORTHERN GEORGIA. IN THE MEANTIME...LOW
PRESSURE WILL DEVELOP OVER THE MISSISSIPPI VALLEY AND HEAD E/NE
THROUGH THE OHIO VALLEY TO NORTHERN PORTIONS OF THE MID ATLANTIC
STATES. THIS WILL BRING THE FRONT BACK TO THE NORTH OF OUR AREA...
INCREASING BOTH TEMPERATURE AND MOISTURE. UNCERTAINTY WITH THE
TIMING OF ANY PCPN EXISTS FOR TUESDAY THROUGH THURSDAY. INTRODUCED
CHC (30 PERCENT) SHOWERS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
UPPER LEVEL RIDGING MAY LIMIT PCPN POTENTIAL.
HIGH TEMPERATURES IN THE 60S MONDAY WARM TO THE MID TO UPPER 70S
(COOLER NEAR THE COAST) WEDNESDAY AND THURSDAY. LOWS AROUND 40 TO
THE MID 40S MONDAY MORNING WARM TO THE MID TO UPPER 50S WEDNESDAY
AND THURSDAY MORNINGS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
A WEAKENING MESOSCALE CONVECTIVE VORTICITY MAX IS MOVING ACROSS
THE AREA THIS AFTERNOON. THIS IS BEING ACCOMPANIED WITH SOME
SHOWERS AND MAY EVEN PRODUCE AN ISOLATED THUNDERSTORM OVER
NORTHEAST NORTH CAROLINA TO SOUTHEAST VIRGINIA. THIS WILL BE EAST
OF THE AREA BY LATE AFTERNOON. A WARM FRONT IS MOVING SLOWLY NORTH
AND TO THE NORTH OF IT FROM RIC TO SBY ARE AREA OF IFR CEILINGS.
AS THE FRONT MOVES NORTH AND WINDS BECOME MORE SOUTHWEST EXPECT
CEILINGS WILL LIFT TO MVFR TO VFR RANGE OVER THE ENTIRE AREA. A
COLD FRONT WILL CROSS THE AREA TONIGHT AND THIS WILL CLEAR THE
CLOUDS OUT OF THE AREA WITH VFR CONDITIONS FOR FRIDAY INTO FRIDAY
NIGHT. WINDS WILL BE BREEZY ON FRIDAY. FOR THE WEEKEND A FRONTAL
BOUNDARY WILL BE NEARLY STATIONARY CLOSE TO THE AREA WITH LOWS
MOVING ALONG IT PROVIDING MVFR TO IFR CONDITIONS.
&&
.MARINE...
WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA UNTIL A COLD FRONTAL
PASSAGE SHORTLY AFTER MIDNIGHT. N/NW WINDS INCREASE QUICKLY FROM
NORTH TO SOUTH ACROSS THE WATERS AS A COLD SWEEPS THROUGH. A SCA IS
IN EFFECT FOR ALL THE WATERS FROM 05 TO 18Z. SOME FINE TUNING FOR
ENDING TIMES MAY BE NEEDED DURING FUTURE SHIFTS.
A BROAD NORTHERLY FETCH IN THE OFFSHORE WATERS MAY PRODUCE 5 FT
SEAS IN THE OUTER PORTIONS OF THE COASTAL ZONES ON SUNDAY.
OTHERWISE NO MARINE ISSUES ARE CURRENTLY FORECAST BEYOND THE NW
SURGE THAT OCCURS OVERNIGHT AND FRIDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 2 PM EDT FRIDAY FOR
ANZ630>638-650-652-654-656-658.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR/MAS
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...JAB
MARINE...LSA
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
336 PM EDT THU APR 26 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA THIS EVENING AND
BRING THE CHANCE OF SHOWERS TO THE AREA. HIGH PRESSURE WILL THEN
BUILD IN FROM THE NORTHWEST AND KEEP THE AREA DRY THROUGH FRIDAY.
A FRONTAL BOUNDARY APPROACHING FROM THE SOUTH WILL RETURN THE
CHANCE OF SHOWERS FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
A SURFACE LOW IS CENTERED ALONG OHIO/PA BORDER WITH A POORLY
DEFINED WARM FRONT EXTENDING EASTWARD ACROSS PA. WITH THE
WARM FRONT PUSHING INTO THE AREA. WEAK ISNETROPIC UPLIFT IN THE
WARM SECTOR AHEAD OF THE LOW IS ALLOWING FOR SCATTERED SHOWERS AND
A FEW ISOLATED THUNDERSTORMS TO MOVE ACROSS THE AREA.
THE LOW WILL SHIFT EAST OF THE AREA TONIGHT WITH COOLER, CANADIAN
AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH. GFS/NAM
SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS CLOUD
COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT LOWS
ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE LOWER
30S ACROSS THE EASTERN RIDGES. A FREEZE WARNING HAS BEEN ISSUED
FOR THE EASTERN RIDGES ALONG WITH FOREST COUNTY.
THERE IS OPERATIONAL MODEL AGREEMENT THAT LOW-LEVEL MOISTURE WILL
SHIFT EAST OF THE AREA FRIDAY MORNING WITH THE SURFACE HIGH MOVING
FROM THE MIDWEST INTO THE OHIO VALLEY. A FEW DIURNAL CU MAY DEVELOP
DURING THE DAY FRIDAY, ALTHOUGH SUBSIDENCE ABOVE 800MB WILL ALLOW
FOR MOSTLY SUNNY SKIES. TEMPS ARE CLOSEST TO A MAV/MET BLEND,
RANGING FROM NEAR 50 ALONG THE I-80 CORRIDOR AND EASTERN RIDGES TO
THE THE UPPER 50S IN PORTIONS OF EASTERN OHIO.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
GFS/ECMWF INDICATE A FRONTAL BOUNDARY PULLING FROM THE TN VALLEY
NORTHWARD INTO THE OH VALLEY FRIDAY NIGHT INTO SATURDAY. THE
FRONTAL BOUNDARY IS PROGGED TO MAKE IT AS FAR NORTH AS NORTH-CENTRAL
WV BEFORE RETREATING BACK SOUTHWARD SATURDAY NIGHT. THE NAM12
DEPICTS A WEAK LOW RIDING ALONG THE BOUNDARY WITH THE MORE COARSE
GFS/ECMWF SOLUTIONS WASHING THIS FEATURE OUT. GFS INDICATES WEAK
LIFT PUSHING NORTH OF THE BOUNDARY, AND THUS HAVE LIKELY POPS
CLOSEST TO THE BOUNDARY IN N-CNTRL WV AND CHANCE POPS ELSEWHERE ON
SATURDAY. IF THE NORTHERN EXTENT OF PRECIP CAN MAKE IT TO THE I-80
CORRIDOR, 1000-500MB THICKNESSES 5400M LINE SHOULD BE JUST NORTH AND
THUS PRECIP IS FORECAST TO BE ALL RAIN.
WEAK RIDGING WILL APPROACH FROM THE WEST WITH HIGH PRESSURE BUILDING
IN FROM THE NORTHWEST ON SUNDAY. THIS WILL ALLOW FOR A DRY DAY.
TEMPERATURE FORECAST IS A BIT CHALLENGING, DEPENDING ON THE
NORTHWARD EXTENT OF THE STRONG THERMAL GRADIENT ALONG THE BOUNDARY.
GIVEN THAT THE BOUNDARY IS PROGGED TO MOSTLY REMAIN SOUTH OF THE
AREA, TEMPS ARE FORECAST TO BE QUITE COOL, AROUND 15-20 DEGREES
BELOW NORMAL ON SATURDAY. ABUNDANT SUNSHINE ON SUNDAY WILL ALLOW
FOR TEMPS TO RECOVER NICELY TO 5 TO 10 DEGREES BELOW NORMAL. LOWS
TEMPS WILL DROP TO NEAR OR BELOW FREEZING NORTH AND EAST OF
PITTSBURGH EACH NIGHT AND MENTION OF THIS HAS BEEN ADDED TO THE
HWO.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
BLEND OF RECENT ENSEMBLE MEMBERS OF HPC-PREFERRED ECMWF AND GFS
MODEL OUTPUT SHOW THE UPPER LEVEL JETSTREAM EVOLVING INTO A MORE
ZONAL CONFIGURATION NEXT WEEK. HENCE EXPECT TEMPERATURES THIS PERIOD
TO TREND TOWARD WARMER THAN NORMAL VALUES.
EXPECT MONDAY TO BE DRY, AS CANADIAN HIGH PRESSURE CENTER PASSES
EAST OF THE APPALACHIAN MOUNTAINS BY AFTERNOON. ECMWF AND GFS MOS
SHOW MORNING LOWS CAN BE 10 TO 15 DEGREES COLDER THAN NORMAL AND
SUBFREEZING IN SOME AREAS. AFTERNOON HIGHS MAY WARM TO NEAR
SEASONABLE VALUES.
A LOW PRESSURE SYSTEM, COMING EAST FROM COLORADO, WILL BRING THE
UPPER OHIO VALLEY SHOWERS AND POSSIBLY THUNDERSTORMS LATE TUESDAY
AND WEDNESDAY. WITH THE ZONAL JETSTREAM SHIFTING NORTH BY MID WEEK,
THE NEXT LOW PRESSURE SYSTEM WILL COME EAST FROM MONTANA TO PROVIDE
THE UPPER OHIO VALLEY WITH SHOWERS WEDNESDAY NIGHT AND THURSDAY.
FORECASTED TEMPERATURES TO GO AS WARM AS 10 DEGREES ABOVE NORMAL
LATE TUESDAY INTO THURSDAY PER BLEND OF ECMWF AND GFS MOS.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR AND NAM
MODEL OUTPUT, SHOW AREAS OF MVFR STRATOCUMULUS AND SCATTERED MVFR
SHOWERS ACROSS THE UPPER OHIO VALLEY, ASSOCIATED WITH THE COLD
FRONTAL PASSAGE, CONTINUING INTO EVENING. POST FRONTAL SUBSIDENCE
WILL DISSIPATE ANY REMAINING MVFR STRATOCUMULUS BY 04Z.
SURFACE WINDS WILL BECOME NORTHWEST, WITH GUSTS TO 25 KTS, WITH
THE COLD FRONTAL PASSAGE. NORTHWEST WINDS WILL DECREASE TO 10 KTS BY
04Z.
DAYTIME VERTICAL MIXING DAYTIME FRIDAY WILL PRODUCE VFR CUMULUS
CLOUDS AND WIND GUSTS TO 25 KTS BY AFTERNOON.
.OUTLOOK...THURSDAY NIGHT THROUGH TUESDAY...
EXPECT RENEWED RESTRICTIONS FRIDAY NIGHT AND SATURDAY WITH SHOWERS
ASSOCIATED WITH THE EASTWARD PASSAGE OF A LOW PRESSURE SYSTEM. VFR
SUNDAY INTO TUESDAY. RESTRICTIONS WILL AGAIN BE POSSIBLE LATE
TUESDAY DUE TO PREFRONTAL SHOWERS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR MDZ001.
OH...NONE.
PA...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR PAZ009-074-076.
WV...FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
213 PM EDT THU APR 26 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA THIS AFTERNOON AND
BRING THE CHANCE OF SHOWERS TO THE AREA UNTIL THIS EVENING. HIGH
PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA
DRY TONIGHT THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM
THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
ACCOUNT FOR THE LATEST RADAR AND SKY TRENDS.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SLIDING
ACROSS THE NORTHERN GREAT LAKES, LEAVING THE UPPER OHIO VALLEY IN
A WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A LOW IS CENTERED
IN EASTERN OHIO WITH A POORLY DEFINED WARM FRONT EXTENDING
EASTWARD INTO WESTERN PA. WITH THE WARM FRONT PUSHING INTO THE
AREA, WARM AIR ADVECTION HAS ALLOWED TEMPS TO WARM INTO THE 60S
ACROSS MUCH OF THE AREA. ALONG AND BEHIND THE LOW, SAT WV IMAGERY
INDICATES A DRY PUNCH OF AIR WITH COOLER TDS FILTERING INTO
CENTRAL OHIO AND BRING AN END TO SHOWERS.
THE WEAK SURFACE LOW WILL MOVE ACROSS WESTERN PA THIS AFTERNOON WITH
WEAK ISENTROPIC LIFT IN WARM AIR ADVECTION AHEAD OF IT PROVIDING
THE CHANCE FOR SHOWERS ACROSS THE AREA. DEEPER MOISTURE WILL
SHIFT EAST OF THE AREA BEHIND THE LOW, WITH THE CHANCE OF SHOWERS
DIMINISHING FROM WEST TO EAST BY 00Z. WITH SURFACE OBS TRENDING
WARMER, FORECAST IS A BLEND OF THE LAMP/HRRR FOR HIGH TEMPS,
REACHING THE LOWER TO MID 60S ACROSS MUCH OF THE AREA.
TONIGHT...THE LOW WILL SHIFT EAST OF THE AREA WITH COOLER,
CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH.
GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS
CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT
LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE
LOWER 30S ACROSS THE EASTERN RIDGES. WITH TEMPS FORECAST TO DROP
TO MARGINALLY NEAR FREEZING AND UNCERTAINTY WITH CLOUD COVERAGE, A
FREEZE WATCH REMAINS IN EFFECT FOR THE HIGHER ELEVATIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
BOUNDARY WILL PUSH SOUTH OF REGION FRIDAY AS PIECE OF COLD
CANADIAN HIGH MOVES ACROSS AREA. BOUNDARY WILL QUICKLY RETURN
FRIDAY NIGHT AS SHORTWAVE AND SURFACE LOW PRESSURE MOVE FROM THE
CENTRAL PLAINS TO THE MID ATLANTIC STATES ALONG FRONT. RAIN WILL
SPREAD NORTH ACROSS AREA SATURDAY MORNING WITH LIKELY POPS FOR THE
AFTERNOON. 850MB TEMPS NEAR -2C AND BORDERLINE 1000-850MB
THICKNESS MAY ALLOW FOR A BIT OF SNOW TO MIX IN AT THE START
ACROSS THE NORTH AND SINCE THIS WAS ALREADY IN PREVIOUS FORECAST
LEFT AS IS. SURFACE LOW EXITS OFF THE EAST COAST AND PULLS COLD
FRONT SOUTH OF REGION SATURDAY NIGHT AND ANOTHER COLD CANADIAN
HIGH MOVES SOUTH ACROSS THE REGION. FORECAST USED A BLEND OF THE
GFS/ECMWF. TEMPERATURES WILL AVERAGE AT LEAST 10 DEGREES BELOW
AVERAGE THROUGH PERIOD.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
COLD HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS SUNDAY
WITH A WARMER DAY MONDAY WITH RETURN SOUTHERLY FLOW ON BACKSIDE OF
HIGH MONDAY. ANOTHER APPROACHING WARM FRONT WILL SPREAD SCATTERED
PRECIPITATION BACK INTO THE REGION TUESDAY AND WEDNESDAY.
TEMPERATURES ARE FORECAST TO BE AROUND 10 DEGREES BELOW NORMAL
SUNDAY...CLOSE TO NORMAL MONDAY...THEN WARM TO A FEW DEGREES
ABOVE NORMAL BY WEDNESDAY.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR AND NAM
MODEL OUTPUT, SHOW AREAS OF PREFRONTAL MVFR STRATOCUMULUS AND
SCATTERED MVFR SHOWERS ACROSS THE UPPER OHIO VALLEY CONTINUING INTO
THE AFTERNOON. EXPECT THE COLD FRONTAL PASSAGE LATE THIS AFTERNOON
FOLLOWED BY A POST FRONTAL SUBSIDENCE THAT WILL DISSIPATE ANY
REMAINING MVFR STRATOCUMULUS BY 04Z.
SURFACE WINDS WILL BE FROM THE SOUTHWEST 10 TO 20 KTS THIS
AFTERNOON, SHIFTING TO NORTHWEST, WITH GUSTS TO 25 KTS, WITH THE
COLD FRONTAL PASSAGE. NORTHWEST WINDS WILL DECREASE TO 10 KTS BY
04Z.
DAYTIME VERTICAL MIXING DAYTIME FRIDAY WILL PRODUCE VFR CUMULUS
CLOUDS AND WIND GUSTS TO 25 KTS BY AFTERNOON.
.OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
EXPECT RENEWED RESTRICTIONS FRIDAY NIGHT AND SATURDAY WITH SHOWERS
ASSOCIATED WITH THE EASTWARD PASSAGE OF A LOW PRESSURE SYSTEM. VFR
SUNDAY AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WATCH FROM 1 AM EDT FRIDAY THROUGH FRIDAY MORNING FOR
MDZ001.
OH...NONE.
PA...FREEZE WATCH FROM 1 AM EDT FRIDAY THROUGH FRIDAY MORNING FOR
PAZ074-076.
WV...FREEZE WATCH FROM 1 AM EDT FRIDAY THROUGH FRIDAY MORNING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1216 PM EDT THU APR 26 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA THIS AFTERNOON AND
BRING THE CHANCE OF SHOWERS TO THE AREA UNTIL THIS EVENING. HIGH
PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA
DRY TONIGHT THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM
THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
INCREASE TEMPS ACROSS THE AREA AND LOWER POPS ACROSS THE SOUTH.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SLIDING
ACROSS THE NORTHERN GREAT LAKES, LEAVING THE UPPER OHIO VALLEY IN
A WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A LOW IS CENTERED
ACROSS THE INDIANA-OHIO BORDER WITH A POORLY DEFINED WARM FRONT
EXTENDING EASTWARD ACROSS OHIO AND INTO WESTERN PA. WITH THE WARM
FRONT PUSHING INTO THE AREA, WARM AIR ADVECTION HAS ALLOWED TEMPS
TO WARM INTO THE 50S ACROSS MUCH OF THE AREA. ALONG AND BEHIND THE
LOW, SAT WV IMAGERY INDICATES A DRY PUNCH OF AIR WITH COOLER TDS
FILTERING IN ITS WAKE.
THE WEAK SURFACE LOW WILL MOVE INTO WESTERN PA THIS AFTERNOON WITH WEAK
ISENTROPIC LIFT IN WARM AIR ADVECTION AHEAD OF IT PROVIDING THE
CHANCE FOR SHOWERS ACROSS THE AREA. A SCHC OF THUNDER HAS BEEN
MENTIONED ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV
WITH THE RUC INDICATING MODERATE ELEVATED INSTABILITY THERE.
DEEPER MOISTURE WILL SHIFT EAST OF THE AREA BEHIND THE LOW, WITH
THE CHANCE OF SHOWERS DIMINISHING FROM WEST TO EAST BY 00Z. WITH
SURFACE OBS TRENDING WARMER, FORECAST IS A BLEND OF THE LAMP/HRRR
FOR HIGH TEMPS, REACHING THE LOWER TO MID 60S ACROSS MUCH OF THE
AREA.
TONIGHT...THE LOW WILL SHIFT EAST OF THE AREA WITH COOLER,
CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH.
GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS
CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT
LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE
LOWER 30S ACROSS THE EASTERN RIDGES. WITH TEMPS FORECAST TO DROP
TO MARGINALLY NEAR FREEZING AND UNCERTAINTY WITH CLOUD COVERAGE, A
FREEZE WATCH REMAINS IN EFFECT FOR THE HIGHER ELEVATIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
BOUNDARY WILL PUSH SOUTH OF REGION FRIDAY AS PIECE OF COLD
CANADIAN HIGH MOVES ACROSS AREA. BOUNDARY WILL QUICKLY RETURN
FRIDAY NIGHT AS SHORTWAVE AND SURFACE LOW PRESSURE MOVE FROM THE
CENTRAL PLAINS TO THE MID ATLANTIC STATES ALONG FRONT. RAIN WILL
SPREAD NORTH ACROSS AREA SATURDAY MORNING WITH LIKELY POPS FOR THE
AFTERNOON. 850MB TEMPS NEAR -2C AND BORDERLINE 1000-850MB
THICKNESS MAY ALLOW FOR A BIT OF SNOW TO MIX IN AT THE START
ACROSS THE NORTH AND SINCE THIS WAS ALREADY IN PREVIOUS FORECAST
LEFT AS IS. SURFACE LOW EXITS OFF THE EAST COAST AND PULLS COLD
FRONT SOUTH OF REGION SATURDAY NIGHT AND ANOTHER COLD CANADIAN
HIGH MOVES SOUTH ACROSS THE REGION. FORECAST USED A BLEND OF THE
GFS/ECMWF. TEMPERATURES WILL AVERAGE AT LEAST 10 DEGREES BELOW
AVERAGE THROUGH PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
COLD HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS SUNDAY
WITH A WARMER DAY MONDAY WITH RETURN SOUTHERLY FLOW ON BACKSIDE OF
HIGH MONDAY. ANOTHER APPROACHING WARM FRONT WILL SPREAD SCATTERED
PRECIPITATION BACK INTO THE REGION TUESDAY AND WEDNESDAY.
TEMPERATURES ARE FORECAST TO BE AROUND 10 DEGREES BELOW NORMAL
SUNDAY...CLOSE TO NORMAL MONDAY...THEN WARM TO A FEW DEGREES
ABOVE NORMAL BY WEDNESDAY.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
BLEND OF RECENT SURFACE AND RADAR DATA, COUPLED WITH HRRR AND NAM
MODEL OUTPUT, SHOW AREAS OF PREFRONTAL MVFR STRATOCUMULUS AND
SCATTERED MVFR SHOWERS ACROSS THE UPPER OHIO VALLEY CONTINUING INTO
THE AFTERNOON. EXPECT THE COLD FRONTAL PASSAGE LATE THIS AFTERNOON
FOLLOWED BY A POST FRONTAL SUBSIDENCE THAT WILL DISSIPATE ANY
REMAINING MVFR STRATOCUMULUS BY 04Z.
SURFACE WINDS WILL BE FROM THE SOUTHWEST 10 TO 20 KTS THIS
AFTERNOON, SHIFTING TO NORTHWEST, WITH GUSTS TO 25 KTS, WITH THE
COLD FRONTAL PASSAGE. NORTHWEST WINDS WILL DECREASE TO 10 KTS BY
04Z.
DAYTIME VERTICAL MIXING DAYTIME FRIDAY WILL PRODUCE VFR CUMULUS
CLOUDS AND WIND GUSTS TO 25 KTS BY AFTERNOON.
.OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
EXPECT RENEWED RESTRICTIONS FRIDAY NIGHT AND SATURDAY WITH SHOWERS
ASSOCIATED WITH THE EASTWARD PASSAGE OF A LOW PRESSURE SYSTEM. VFR
SUNDAY AND MONDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
MDZ001.
OH...NONE.
PA...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
PAZ074-076.
WV...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1107 AM EDT THU APR 26 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA THIS AFTERNOON AND
BRING THE CHANCE OF SHOWERS TO THE AREA UNTIL THIS EVENING. HIGH
PRESSURE WILL THEN BUILD IN FROM THE NORTHWEST AND KEEP THE AREA
DRY TONIGHT THROUGH FRIDAY. A FRONTAL BOUNDARY APPROACHING FROM
THE SOUTH WILL RETURN THE CHANCE OF SHOWERS FRIDAY NIGHT INTO
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO
INCREASE TEMPS ACROSS THE AREA AND LOWER POPS ACROSS THE SOUTH.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH SLIDING
ACROSS THE NORTHERN GREAT LAKES, LEAVING THE UPPER OHIO VALLEY IN
A WEST-NORTHWESTERLY FLOW. AT THE SURFACE, A LOW IS CENTERED
ACROSS THE INDIANA-OHIO BORDER WITH A POORLY DEFINED WARM FRONT
EXTENDING EASTWARD ACROSS OHIO AND INTO WESTERN PA. WITH THE WARM
FRONT PUSHING INTO THE AREA, WARM AIR ADVECTION HAS ALLOWED TEMPS
TO WARM INTO THE 50S ACROSS MUCH OF THE AREA. ALONG AND BEHIND THE
LOW, SAT WV IMAGERY INDICATES A DRY PUNCH OF AIR WITH COOLER TDS
FILTERING IN ITS WAKE.
THE WEAK SURFACE LOW WILL MOVE INTO WESTERN PA THIS AFTERNOON WITH WEAK
ISENTROPIC LIFT IN WARM AIR ADVECTION AHEAD OF IT PROVIDING THE
CHANCE FOR SHOWERS ACROSS THE AREA. A SCHC OF THUNDER HAS BEEN
MENTIONED ACROSS PORTIONS OF EASTERN OHIO AND NORTH-CENTRAL WV
WITH THE RUC INDICATING MODERATE ELEVATED INSTABILITY THERE.
DEEPER MOISTURE WILL SHIFT EAST OF THE AREA BEHIND THE LOW, WITH
THE CHANCE OF SHOWERS DIMINISHING FROM WEST TO EAST BY 00Z. WITH
SURFACE OBS TRENDING WARMER, FORECAST IS A BLEND OF THE LAMP/HRRR
FOR HIGH TEMPS, REACHING THE LOWER TO MID 60S ACROSS MUCH OF THE
AREA.
TONIGHT...THE LOW WILL SHIFT EAST OF THE AREA WITH COOLER,
CANADIAN AIR FILTERING INTO THE AREA ON THE EAST SIDE OF A HIGH.
GFS/NAM SUPPORT LOW-LEVEL MOISTURE LINGERING INITIALLY, AND THUS
CLOUD COVERAGE WILL NEGATE RADIATIONAL COOLING EARLY ON. OVERNIGHT
LOWS ARE FORECAST TO BE IN THE MID 30S ACROSS THE LOWLANDS AND THE
LOWER 30S ACROSS THE EASTERN RIDGES. WITH TEMPS FORECAST TO DROP
TO MARGINALLY NEAR FREEZING AND UNCERTAINTY WITH CLOUD COVERAGE, A
FREEZE WATCH REMAINS IN EFFECT FOR THE HIGHER ELEVATIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
BOUNDARY WILL PUSH SOUTH OF REGION FRIDAY AS PIECE OF COLD
CANADIAN HIGH MOVES ACROSS AREA. BOUNDARY WILL QUICKLY RETURN
FRIDAY NIGHT AS SHORTWAVE AND SURFACE LOW PRESSURE MOVE FROM THE
CENTRAL PLAINS TO THE MID ATLANTIC STATES ALONG FRONT. RAIN WILL
SPREAD NORTH ACROSS AREA SATURDAY MORNING WITH LIKELY POPS FOR THE
AFTERNOON. 850MB TEMPS NEAR -2C AND BORDERLINE 1000-850MB
THICKNESS MAY ALLOW FOR A BIT OF SNOW TO MIX IN AT THE START
ACROSS THE NORTH AND SINCE THIS WAS ALREADY IN PREVIOUS FORECAST
LEFT AS IS. SURFACE LOW EXITS OFF THE EAST COAST AND PULLS COLD
FRONT SOUTH OF REGION SATURDAY NIGHT AND ANOTHER COLD CANADIAN
HIGH MOVES SOUTH ACROSS THE REGION. FORECAST USED A BLEND OF THE
GFS/ECMWF. TEMPERATURES WILL AVERAGE AT LEAST 10 DEGREES BELOW
AVERAGE THROUGH PERIOD.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
COLD HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS SUNDAY
WITH A WARMER DAY MONDAY WITH RETURN SOUTHERLY FLOW ON BACKSIDE OF
HIGH MONDAY. ANOTHER APPROACHING WARM FRONT WILL SPREAD SCATTERED
PRECIPITATION BACK INTO THE REGION TUESDAY AND WEDNESDAY.
TEMPERATURES ARE FORECAST TO BE AROUND 10 DEGREES BELOW NORMAL
SUNDAY...CLOSE TO NORMAL MONDAY...THEN WARM TO A FEW DEGREES
ABOVE NORMAL BY WEDNESDAY.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
A SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW WILL MOVE SOUTHEAST
FROM THE UPPER MS VALLEY AND ACROSS THE OH VALLEY LATE TONIGHT AND
THURSDAY MORNING. MVFR RESTRICTIONS AND PATCHY IFR CAN BE EXPECTED
IN SHOWERS AND ISOLATED THUNDERSTORMS THROUGH THE MORNING HOURS. A
FRONT WILL CROSS THE REGION BY LATE DAY CONTINUING THE CHANCE FOR
MVFR RESTRICTIONS...AS SUGGESTED BY BOTH LAMP GUIDANCE AND SREF
PROBABILITIES.
WINDS WILL GENERALLY REMAIN LIGHT OVERNIGHT...WITH THE EXCEPTION
OF ANY TAF LOCATION THAT EXPERIENCES A THUNDERSTORM. WINDS WILL
SHIFT FROM SE-NW AND BECOME GUSTY TO 25KTS IN THE AFTERNOON WITH
THE PASSAGE OF THE FRONT.
.OUTLOOK...THURSDAY NIGHT THROUGH MONDAY...
A SURFACE RIDGE SHOULD SUPPORT VFR WEATHER FOR THURSDAY NIGHT INTO
FRIDAY BEFORE ANOTHER QUICK MOVING LOW PRESSURE SYSTEM BRINGS
AREAS OF RAIN WITH MVFR/IFR RESTRICTIONS FRIDAY NIGHT AND
SATURDAY. VFR WEATHER SHOULD RETURN FOR SUNDAY AND MONDAY AS HIGH
PRESSURE BUILDS SOUTHWARD ACROSS THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
MDZ001.
OH...NONE.
PA...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
PAZ074-076.
WV...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
128 AM EDT THU APR 26 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 414 PM EDT WED APR 25 2012
SEVERAL EMBEDDED SHORTWAVES HAVE BEEN MOVING THROUGH THE NW FLOW
ACROSS THE UPPER MISS VALLEY AND UPPER GREAT LKS TODAY. WHEN THESE
WAVES HAVE INTERACTED WITH THE H925-700 WAA UNDER WEAK SW FLOW...AS
SEEN ON RUC ANALYSIS...THEY HAVE PRODUCED AREAS OF LIGHT RAIN
SHOWERS OVER NE MN...NW WI AND ALONG THE WI/MI BORDER. WITH THE
LLVL DRY AIR IN PLACE OVER MUCH OF UPPER MI AND LITTLE ESE MOVEMENT
OF THE SHOWERS...THEY HAVE STRUGGLED TO EFFECT THE AREA. ATTENTION
THEN TURNS FARTHER UPSTREAM IN SW ONTARIO WHERE ANOTHER SHORTWAVE
AND WEAK WAA HAS BEEN SLOWLY MOVING SE INTO WRN LK SUPERIOR. THIS
AREA OF MOISTURE/WAA WILL MERGE WITH SHORTWAVE DROPPING S JUST E OF
LK WINNIPEG AND MOVE ACROSS LAKE SUPERIOR TONIGHT. 06 AND 12Z MODEL
RUNS REALLY TRENDED THAT DIRECTION AND EARLIER UPDATE TO THE
FORECAST WENT WITH THIS IDEA.
THINK THESE SHOWERS WILL SLIDE INTO THE WRN PART OF UPPER MI THIS
EVENING AND TRY TO SPEED UP AS FRONTAL BOUNDARY ASSOCIATED WITH
THE SHORTWAVE PUSHES IT TO THE SE. AS THIS SLIDES ESE ACROSS THE
AREA...IT WILL BE INTERACTING WITH THE LINGERING DRY LLVL AIR.
MODELS CONSISTENT ON THIS PCPN DIMINISHING SOME AS IT HITS THE DRIER
AIR...SO HAVE THE LIKELY POPS OVER THE WRN HALF OF THE CWA AN
DIMINISHED TO CHANCES AS IT MOVES INTO THE DRIER AIR. AFTER THE
INITIAL PCPN SLIDES THROUGH...COULD HAVE A SECONDARY AREA ASSOCIATED
WITH THE SFC-H850 FRONT MOVING THROUGH AFTER 6Z. FORCING ALONG THE
FRONT...ALONG WITH THE STRONG SHORTWAVE...SHOULD LEAD TO ANOTHER
BAND OF RAIN...POTENTIALLY MIXING WITH OR CHANGING TO SNOW
AFFECTING THE NRN HALF OF THE CWA. SOME OF THESE SHOWERS WILL BE
ENHANCED IN THE UPSLOPE N FLOW AREAS...WHICH IF IT CHANGES TO ALL
SNOW...COULD PRODUCE A LIGHT DUSTING OF SNOW OVER THE WEST AND
NCNTRL. EXPECT WINDS TO QUICKLY PICKUP ALONG THIS FRONT AND GUST TO
25-30KTS NEAR LK SUPERIOR LATE TONIGHT AND INTO THURS MORNING.
CONSIDERED PUTTING UP A GALE FOR THE ERN HALF OF LK
SUPERIOR...AS WINDS RIGHT ALONG THE FRONT WILL GUST TO 35 AND
POTENTIALLY 40KTS...BUT SHOULD ONLY BE FOR A BRIEF 1-2HR WINDOW
BEFORE DIMINISHING BACK BELOW 35KTS.
AS THE FRONT QUICKLY MOVES THROUGH...H850 TEMPS AROUND -9C WILL
PROVIDE ENOUGH DELTA-T FOR CLOUDS AS LONG AS MOISTURE REMAINS.
SHOULD BE ENOUGH LLVL MOISTURE...AROUND H925-850...TO SUSTAIN
CLOUDS NEAR LK SUPERIOR FOR THE FIRST PART OF THE MORNING OVER THE
WEST AND INTO THE AFTN OVER THE EAST. DID LEAVE SOME LINGERING
-SHSN FOR UPSLOPE LOCATIONS NEAR LK SUPERIOR OVER THE NCNTRL AND
EAST...BUT SHOULD DIMINISH FAIRLY QUICKLY WITH THE DRY AIR AND
SUBSIDENCE FROM HIGH PRESSURE RIDGE MOVING OVER WRN LK SUPERIOR. IT
WILL FEEL MUCH COOLER THAN TODAY OVER MUCH OF THE AREA...BUT
ESPECIALLY OVER THE N HALF...AS THE COLD AIR AND WINDS OFF LK
SUPERIOR WILL MAKE IT FEEL MUCH COLDER THAT THE LOW-MID 40S HIGHS.
IN ADDITION...WITH THE DRY AIR ALOFT AND MIXING WITH THE WINDS WILL
LEAD TO FALLING DEWPOINTS FROM WEST TO EAST. RH FALLING TO 25-30
PERCENT OVER THE WEST...BUT FORTUNATELY THE WINDS WILL BE
DIMINISHING AND COOLER TEMPS WILL LIMIT FIRE WX CONCERN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 414 PM EDT WED APR 25 2012
DRY CONDITIONS MAIN THEME OF LONG TERM. VERY LIMITED OPPORTUNITIES
FOR RAINFALL IS IN THE FCST THROUGH MONDAY AS HIGH PRESSURE REIGNS
OVR THE REGION. INITIALLY WINDS WILL BE OUT OF THE NORTH OR NORTHEAST
AS THE HIGH CENTER SETTLES FM NORTHERN MANITOBA AND NINAVUT CANADA
ACROSS MUCH OF THE EASTERN CONUS BY EARLY NEXT WEEK. HIGH IS FCST TO
PUSH TOWARD EAST CONUS COAST BY TUESDAY ALLOWING SOUTH TO SOUTHWEST
RETURN FLOW TO FORM FM THE PLAINS INTO THE WESTERN GREAT LAKES.
MOISTURE RETURN INTO GREAT LAKES IS MINIMAL AND DESPITE APPROACH OF A
SFC-H85 TROUGH BELIEVE CHANCES OF ANY PRECIPITATION ARE PRETTY SMALL.
CONSENSUS OF AVAILABLE MODELS GIVES LOW CHANCE POPS TUESDAY THROUGH
WEDNESDAY AS THE TROUGH WORKS THROUGH.
LARGE TROUGH RESIDING OVER MUCH OF EASTERN CANADA AND NORTHEAST
CONUS WILL KEEP TEMPS GENERALLY AT OR BLO NORMAL THROUGH MUCH OF THE
PERIOD...ESPECIALLY NEAR LK SUPERIOR WITH PERSISTENT ONSHORE FLOW.
NEAR NORMAL OR POSSIBLY SLIGHTLY ABOVE NORMAL TEMPS MAY OCCUR OVR
INTERIOR CNTRL TOWARD WI BORDER AS DEEP MIXING OFFSETS NORTHERLY
WINDS. PRIME ISSUE THROUGH THE EXTENDED PERIOD REALLY IS DWPNTS/RH
VALUES WITH THE DRY HIGH DOMINATING. CORE OF DRIEST AIR IS OVER THE
AREA THURSDAY NIGHT THROUGH MONDAY. LOWERED DWPNTS MORE TOWARD MIXED
LAYER DWPNT TOOL OUTPUT FOR AFTN HOURS ON FRIDAY...SATURDAY...AND
SUNDAY. SIMILAR TO EARLIER THIS WEEK...GIVEN EXTENT OF DRY AIRMASS
OVERHEAD /PWATS 10-20 PCT OF NORMAL/...WOULD NOT BE SHOCKED AT ALL
TO SEE AFTN DWPNTS NEAR 0F AND RH VALUES WELL BLO 20 PCT. NNW
GRADIENT WINDS STRONGEST ON FRIDAY AFTN OVR EAST HALF...SO THAT IS
PROBABLY WHEN FIRE WX ISSUES WOULD BE MAXIMIZED. OTHERWISE...THROUGH
THE WEEKEND...WINDS BECOME PRETTY LIGHT AS HIGH PRESSURE RIDGE AXIS
IS OVERHEAD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 124 AM EDT THU APR 26 2012
VIGOROUS DISTURBANCE DROPPING SE THRU NRN ONTARIO TOWARD LAKE
SUPERIOR WILL DRIVE A COLD FRONT ACROSS THE AREA OVERNIGHT.
ALONG/AHEAD OF FRONT...EXPECT SOME -SHRA AT KIWD/KCMX/KSAW WITH CIGS
GENERALLY IN THE MVFR RANGE PER UPSTREAM OBS...ALTHOUGH KIWD DID COME
IN WITH A 300 FT CIG IN THE PAST HR SO DID ACCOUNT FOR THIS WITH THE
06Z ISSUANCE. ONCE WINDS SHIFT NORTHERLY/INCREASE AFTER FROPA...NOT
OUT OF THE QUESTION THAT A PERIOD OF IFR CIGS COULD OCCUR...ESPECIALLY
AT KIWD/KSAW SINCE WINDS AT THOSE SITES WILL HAVE A MORE DIRECT
UPSLOPE COMPONENT. -SHRA WILL MIX WITH OR CHANGE TO -SHSN LATE IN THE
NIGHT AS COLDER AIR SURGES INTO THE AREA...BUT PCPN WILL END EARLY TO
MID MORNING AS CLOUD DECK THINS UNDER ADVECTION OF DRIER AIR. CLOUDS
SHOULD THEN SCATTER OUT OR CLEAR AT KIWD/KCMX BY LATE MORNING/EARLY
AFTN...BUT NOT UNTIL MID AFTN AT KSAW. IN ADDITION...EXPECT GUSTY
WINDS BEHIND FRONT OVERNIGHT THRU AT LEAST MID AFTN AS UNSTABLE LOW-
LEVELS RESULT IN EFFICIENT MIXING. GUSTS TO 25-30KT WILL BE COMMON AT
KCMX/KSAW... ESPECIALLY AT KSAW. WINDS WILL DIMINISH IN THE EVENING
UNDER CLEAR SKIES. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 PM EDT WED APR 25 2012
LOW PRESSURE OVER IOWA WILL SLIDE SE TONIGHT AND DRAG A SFC
TROUGH SE ACROSS LAKE SUPERIOR. STRONG CANADIAN HIGH TRIES TO
PUSH IN BEHIND IT AND WILL LEAD TO GUSTY NNW WINDS LATE TONIGHT
INTO THURS MORNING. EXPECT A FEW GALE FORCE GUSTS TO 35KTS OVER
CNTRL/ERN LK SUPERIOR WITH THIS STRONG GRADIENT. CONSIDERED PUTTING
UP A GALE FOR A COUPLE HOUR PERIOD AS THIS BOUNDARY MOVES ACROSS LK
SUPERIOR...BUT WITH THE SHORT TIME PERIOD...OPTED TO MENTION THE
GUSTS AT THIS TIME. THE CANADIAN HIGH PRESSURE RIDGE WILL THEN MOVE
OVER THE UPPER GREAT LKS BY THURS NIGHT DIMINISHING THE WINDS BELOW
20KTS. THIS WILL CONTINUE THROUGH MONDAY...AS THE HIGH MOVES
SOUTHEAST ACROSS THE GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 5 AM TO 11 AM EDT THIS MORNING FOR LSZ244-245-
248>250-264>266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...SRF
AREA FORECAST DISCUSSION
NWS JACKSON MS
1050 AM CDT THU APR 26 2012
.UPDATE...LATEST NAM AND OTHER HIRES MODELS SHOW A FEW SHOWERS
DEVELOPING OVER THE NORTHERN PORTIONS OF THE CWA THIS AFTERNOON INTO
THE EVENING. JAN SOUNDING WAS VERY DRY AND CAPPED. TEMPERATURES IN
THE MID 80S MAY BREAK THE CAP BUT THERE WERE ALREADY MID LEVEL
CLOUDS ACROSS THE DELTA INHIBITING FULL INSOLATION. WL ADD MENTION
OF SPRINKLES FOR THIS AFTERNOON ALONG AND NORTH OF HIGHWAY 82
CORRIDOR AND LOOK AT SOME OTHER INFO BEFORE CARRYING ANY POPS THIS
EVENING. A FEW SUBTLE WAVES WERE SHOWING UP IN THE NORTHWEST FLOW
ALOFT VIA SATELLITE IMAGERY AND RUC ANALYSIS. SURFACE BOUNDARY WAS
STILL WELL NORTH DROPPING JUST SOUTH OF THE MID MISSISSIPPI RIVER
VALLEY AND WL STALL NORTH OF OUR CWA. HIGH PRESSURE WAS NOTED OVER
THE GULF AND PROVIDING A WARM SOUTH TO SOUTHWEST WIND. MID 80S
CENTRAL AND SOUTH LOOK ON TARGET. /22/
&&
.AVIATION...MIXTURE OF VFR AND MVFR THIS MNG ACROSS ARKLAMISS
REGION. KGLH/KHBG ARE MVFR /BKN015 CIGS/ AS OF 1430Z AND WILL BECOME
VFR OVER THE NEXT COUPLE OF HOURS WITH KGLH HOLING ON TO MVFR
POSSIBLY THROUGH 17Z DUE TO OVC150 NOT READILY ALLOWING LOW-LVL
MIXING OF THE CURRENT BKN015 STRATUS DECK. A FEW LIGHT SHOWERS COULD
BE POSSIBLE ACROSS N/W AREAS THIS AFTN BUT PROBS NOT GREAT ENOUGH TO
MENTION IN TAFS ATTM. SW/S WINDS WILL BE ELEVATED LATE MNG-AFTN WITH
SUSTAINED WINDS 10-15KT AND GUSTS TO 23KT POSSIBLE (ESPECIALLY FOR
NRN SITES). WINDS WILL SUBSIDE OVERNIGHT WITH PATCHY MVFR
STRATUS/FOG OCCURRING 27/07-14Z AND MIX OUT THROUGH MID-MNG FRIDAY.
/ALLEN/
&&
.PREV DISCUSSION... /ISSUED 354 AM CDT THU APR 26 2012/
SHORT TERM...TODAY THROUGH FRIDAY NIGHT...STRONG SURFACE HIGH
PRESSURE RIDGING WILL PREVAIL OVER MUCH OF THE STATE TODAY...BUT A
BOUNDARY WILL DROP SOUTH INTO NORTHERN MISSISSIPPI LATER THIS
AFTERNOON. THE MODELS SUGGEST QUITE A BIT OF INSTABILITY ACROSS THE
NORTHERN PORTIONS OF THE AREA ALONG WITH PWATS AROUND 1.3 TO 1.4
INCHES LATER THIS AFTERNOON. EXPECT THE CONVECTION TO REMAIN NORTH
OF OUR AREA CLOSER TO THE BOUNDARY THIS AFTERNOON THOUGH...AS STRONG
CAPPING LOOKS LIKE IT WILL INHIBIT CONVECTIVE DEVELOPMENT OVER OUR
AREA. HI-RES MODELS ARE ALSO MAINLY DEVELOPING CONVECTION NORTH OF
OUR AREA THIS AFTERNOON AND EVENING.
RIDGING AT THE SURFACE AND ALOFT WILL STRENGTHEN OVER THE AREA ON
FRIDAY AND FRIDAY NIGHT. TEMPS ARE GOING TO BE VERY WARM THE NEXT
COUPLE OF DAYS WITH HIGHS IN THE MID TO UPPER 80S. THE SURFACE
PRESSURE GRADIENT WILL TIGHTEN EACH AFTERNOON TODAY AND FRIDAY WITH
GUSTS FROM 25-30 MPH LIKELY...ESPECIALLY UP IN THE DELTA. MADE A FEW
ADJUSTMENTS TO GUIDANCE...MAINLY TO HIGH TEMPS AND POPS IN THE
NORTH. EXPECT TEMPS TO BE SLIGHTLY HIGHER THAN WHAT MAV IS
INDICATING...SO BUMPED HIGHS UP A DEGREE OR TWO OVER MOST OF THE
AREA. AS PREVIOUSLY TALKED ABOUT EXPECT THE STRONG CAP TO INHIBIT
CONVECTIVE DEVELOPMENT OVER THE AREA...SO CUT POPS IN THE NORTH./15/
LONG TERM...UPPER RIDGING PERSISTS THIS WEEKEND...ALONG WITH
GENERALLY ANTICYCLONIC FLOW AT 850 MB. THE REMNANTS OF THE SURFACE
TROUGH DROP INTO THE REGION BY SUNDAY BUT WEAK SURFACE CONVERGENCE
ASSOCIATED WITH THIS SHOULD NOT OVERCOME THE HEALTHY CAPPING/CIN
VALUES THAT WILL CONTINUE. ALTHOUGH CAPPING WILL REMAIN IN PLACE
THIS WEEKEND AND CHANCES OF AFTERNOON CONVECTION ARE VERY LOW...OF
SOME CONCERN IS THE FACT THAT INCREASING CAPE AND HIGH LAPSE RATES
INDICATE THAT IF AN ISOLATED CELL CAN GET GOING AND PUSH THROUGH THE
CAP THEN A SEVERE STORM COULD DEVELOP BUT WITH CHANCES SO LOW NO
MENTION OF PRECIP WILL BE ADDED AT THIS TIME FOR SATURDAY OR SUNDAY.
MODELS BEGIN TO TRY TO ERODE THE UPPER RIDGE MONDAY AND
TUESDAY...WEAK WAVES LIFTING INTO THE REGION IN SWLY FLOW ALOFT ON
THE WRN FRINGES OF THE HIGH. WEAK CAPPING CONTINUES BUT WILL BE LESS
PRONOUNCED THAN OVER THE WEEKEND AND LAPSE RATES WILL REMAIN HIGH.
SLIGHT CHANCE POPS PAINTED BY MOS FOR EARLY NEXT WEEK LOOK
REASONABLE IF THE RIDGE DOES INDEED BEGINS TO WEAKEN. WITH
RELATIVELY LOW COVERAGE A RELATIVELY LONG PERIOD AWAY WILL NOT ADD
CONVECTION RISKS TO THE HWO AT THIS TIME FOR NEXT WEEK BUT A SLIGHT
POTENTIAL DOES EXIST IF THE UPPER RIDGE DOES BEGIN TO GIVE WAY.
PERSISTENT UPPER RIDGING WILL RESULT IN A CONTINUED WARM SPELL
ACROSS THE AREA...PARTICULARLY FOR AFTERNOON HIGHS. DAYTIME READINGS
IN THE UPPER 80S ARE FORECAST BY MEX MOS FOR SUNDAY/MONDAY DURING
AND IMMEDIATELY FOLLOWING THE PEAK OF UPPER RIDGING. CONSIDERING
THAT MANY LOCATIONS CLIMBED INTO THE MID 80S YESTERDAY AND RECORD
HIGHS CLIMB INTO THE LOW TO MID 90S BY MONDAY...MEX MOS NUMBERS DO
NOT LOOK UNREASONABLE AND WILL BE FOLLOWED. /03/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 85 62 86 63 / 9 8 9 11
MERIDIAN 87 61 87 61 / 10 11 7 13
VICKSBURG 86 62 85 62 / 9 7 11 12
HATTIESBURG 88 63 86 62 / 3 5 2 7
NATCHEZ 85 63 85 64 / 4 6 2 7
GREENVILLE 84 65 85 65 / 17 14 12 13
GREENWOOD 83 64 84 64 / 17 13 11 13
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
22/ALLEN/15/03
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
923 PM CDT FRI APR 27 2012
.UPDATE...
ISSUED AT 922 PM CDT FRI APR 27 2012
MADE ADJUSTMENTS TO RAIN CHANCES AND TEMPERATURES THE REST OF THE
NIGHT INTO SATURDAY MORNING BASED ON CURRENT TRENDS. OVERALL AREAL
COVERAGE OF STORMS OVER EASTERN KANSAS AND WESTERN MISSOURI HAS
DECREASED THE LAST TWO HOURS. ONE EXCEPTION IS AN ISOLATED STORM
THAT RECENTLY DEVELOPED AND HAS BECOME SEVERE BETWEEN MKC AND JLN.
RUNS OF THE HRRR REFLECTIVITY OUTPUT HAS SHOWN CORRECTLY THE
OVERALL LACK OF PRECIPITATION THIS EVENING...AND SHOWS THAT STORMS
DEVELOPING OVER WESTERN MO WILL MOVE NORTHEAST WITH TIME. RUC RUNS
CONTINUE TO SHOW A MARKED INCREASE IN 925-850MB MOISTURE CONVERGENCE
OVER THE NORTHEASTERN HALF OF THE CWA BY 06Z ON THE NOSE OF A BROAD
45KT LOW LEVEL JET. HAVE LOWERED POPS A BIT OVER THE SOUTHERN PART
OF THE CWA AND MAINTAINED LIKELY POPS TO THE NORTH OF I-70 BETWEEN
05-09Z BEFORE THE LOW LEVEL MOISTURE CONVERGENCE LIFTS NORTHEASTWARD.
CONSEQUENTLY ONLY HAVE SLIGHT CHANCES LATE TONIGHT INTO EARLY SATURDAY
OVER THE WHOLE CWA BEFORE THE POTENTIAL FOR SCATTERED THUNDERSTORMS
INCREASES AHEAD OF THE SURFACE LOW AND ATTENDANT COLD FRONT FROM
14Z ONWARD.
TEMPERATURES WILL LIKELY REMAIN STEADY OR SLOWLY RISE OVER THE SOUTHERN
CWA LATER TONIGHT WHEN WARM FRONT LIFTS NORTH INTO THE AREA.
BRITT
&&
.SHORT TERM...
ISSUED AT 319 PM CDT FRI APR 27 2012
(TONIGHT)
DEALING WITH AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER
WESTERN/SOUTHWESTERN MO EARLIER THIS AFTERNOON AND IS TRACKING TO THE EAST
ACROSS FORECAST AREA AS OF 20Z. IT IS MOVING FAIRLY RAPIDLY AND SHOULD
BE EXITING AFTER 00Z. SO HAVE HIGHEST POPS OVER EASTERN PORTIONS
OF FORECAST AREA THIS EVENING. SOME CONCERN ABOUT ADDITIONAL DEVELOPMENT
AS SURFACE LOW TRACKS ACROSS AREA TONIGHT...SO KEPT HIGHEST POPS
NORTH OF SURFACE LOW TRACK...MAINLY OVER NORTHERN MO...INTO WEST
CENTRAL IL...BEFORE TAPERING OFF TOWARDS DAYBREAK. COULD SEE SOME
BRIEF HEAVY RAINFALL AND SMALL HAIL WITH SOME OF THE STRONGER STORMS.
OTHERWISE...DUE TO CLOUD COVER AND RAINFALL...TEMPS HAVE STRUGGLED
TO RISE MUCH TODAY...SO AS PCPN ENDS...COULD SEE TEMPS ACTUALLY
RISE A BIT BEFORE FALLING OFF. IT WILL BE CHILLY...WITH LOWS TONIGHT
IN THE UPPER 40S FAR NORTH TO THE UPPER 50S FAR SOUTH.
BYRD
&&
.LONG TERM...
ISSUED AT 319 PM CDT FRI APR 27 2012
(SATURDAY THROUGH FRIDAY)
MODELS CONTINUE TO HAVE DIFFERENT SOLUTIONS ON HOW TO HANDLE FRONTAL
BOUNDARY...WITH NAM HAVING BOUNDARY SINK SOUTH OF FORECAST AREA
DURING THE DAY ON SATURDAY...STALLING OUT JUST SOUTH OF FORECAST
AREA SATURDAY NIGHT AND SUNDAY. WHILE GFS/ECMWF HAS IT STALL OUT A
BIT FURTHER NORTH IN SOUTHERN PORTIONS OF FORECAST AREA. WILL LEAN
MORE TOWARDS GFS/ECMWF SOLUTION WITH BEST POPS ALONG AND SOUTH OF
I-70 THROUGH SUNDAY. THEN SUNDAY NIGHT AND MONDAY BETTER RAIN
CHANCES SHIFT TO THE NORTH AS NEXT IN A SERIES OF SHORTWAVES MOVES
ALONG FRONTAL BOUNDARY.
AS FOR TEMPS THROUGH THE PERIOD...SATURDAY WILL STILL BE RATHER
MILD...IN THE MID 60S FAR NORTH TO THE UPPER 70S SOUTH. THEN COOLER
AIR TO MAKE ITS WAY IN FOR THE LAST HALF OF THE WEEKEND BEFORE
MODERATING A BIT BY MONDAY. HIGHS ON SUNDAY WILL ONLY BE AROUND 60
FAR NORTH TO NEAR 70 FAR SOUTH...WARMING UP INTO THE UPPER 60S TO
MID 70S.
BEYOND THAT...WE REMAIN IN ACTIVE PATTERN WITH CHANCES OF SHOWERS
AND THUNDERSTORMS OFF AND ON THROUGH THE REST OF THE FORECAST
PERIOD. TEMPS TO CONTINUE MODERATING NEXT WEEK WITH HIGHS BACK IN
THE MID TO UPPER 70S BY TUESDAY...THEN WARMING UP INTO THE UPPER 70S
TO MID 80S THROUGH THE LAST HALF OF THE WORK WEEK.
BYRD
&&
.AVIATION...
ISSUED AT 638 PM CDT FRI APR 27 2012
STRONG STORM SYSTEM OVER THE GREAT PLAINS WILL SPREAD SHOWERS AND
THUNDERSTORMS ACROSS THE AREA TONIGHT. SOME CONFLICTING
INFORMATION AS TO AREAL COVERAGE AND STRENGTH OF THE
STORMS...ESPECIALLY ALONG AND SOUTH OF THE I-70 CORRIDOR. AT THIS
TIME THINK COVERAGE FROM EAST CENTRAL MISSOURI INTO SOUTHWEST
ILLINOIS WILL LIKELY BE SCATTERED...WHILE COVERAGE WILL BE
SOMEWHAT MORE IN CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST
CENTRAL ILLINOIS. IFR CIGS/VSBYS CERTAINLY A GOOD POSSIBILITY WITH
THUNDERSTORMS...OTHERWISE EXPECT VFR FLIGHT CONDITIONS TO
PREVAIL...WITH SOME POCKETS OF MVFR CIGS MOVING THROUGH CENTRAL
AND NORTHEAST MISSOURI THIS EVENING. CIGS WILL LIKELY FALL TO MVFR
WITH POSSIBLY SOME IFR AFTER THE STORMS PASS LATE TONIGHT.
ALSO...EXPECT LOW LEVEL WIND SHEAR OVER MOST OF THE AREA DURING
THE PRE-DAWN HOURS OF SATURDAY MORNING AFTER THE THUNDERSTORMS
PASS. CIGS SHOULD RISE BACK UP TO VFR AFTER THE COLD FRONT PASSES
SATURDAY MORNING.
SPECIFICS FOR KSTL...
THUNDERSTORM FORECAST UNCERTAIN AT THIS TIME. GETTING CONFLICTING
SIGNALS FROM SHORT-RANGE MODELS...THEREFORE HAVE BACKED OFF
PREVAILING TS TO TEMPO FOR NOW. THINK EITHER THE STORMS NOW OVER
EASTERN KANSAS WILL CONTINUE TO MARCH ACROSS MISSOURI...OR
ADDITIONAL THUNDERSTORM DEVELOPMENT WILL OCCUR OVER THE NEXT
COUPLE OF HOURS. CURRENT THINKING IS THAT STORMS WILL BE SCATTERED
ACROSS THE STL METRO AREA LATE THIS EVENING...BUT AM UNCOMFORTABLE
BACKING OFF BELOW TEMPO UNTIL WE GET A BETTER HANDLE ON THE
SITUATION. UNTIL STORMS FORM...THINK CIGS SHOULD BE VFR WITH THE
POSSIBILITY OF AN INTERMITTENT DIP TO HIGH MVFR. MVFR WILL PREVAIL
LATE TONIGHT AND LOW LEVEL WIND SHEAR WILL BE A PROBLEM AS THE
UPPER SYSTEM RACES AHEAD OF THE SURFACE STORM. CIGS SHOULD COME
BACK UP TO VFR SATURDAY MORNING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
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.
PRECIPIATION 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 CELSIUS 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
AGRESSIVE 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 HASTINGS NE
1207 PM CDT THU APR 26 2012
.UPDATE...OVERALL NO MAJOR CHANGES FOR THE AFTERNOON UPDATE. KEPT
AT LEAST A 20 PERCENT CHANCE OF LIGHT RAIN SHOWERS GOING THROUGH
00Z FOR THE ENTIRE CWA...WITH HIGHER 30-50 PERCENT CHANCES OF
MEASURABLE RAIN ACROSS WESTERN COUNTIES. NEEDLESS TO SAY...THE
ODDS OF SEEING MORE THAN SPRINKLES ACROSS THE MAJORITY OF THE CWA
THROUGH SUNSET IS FAIRLY SLIM...ESPECIALLY IN EASTERN ZONES.
LATEST HRRR STRONGLY SUGGESTS THE SEMI-DECENT COVERAGE OF LIGHT
RAIN CURRENTLY EXTENDING FROM SOUTHWEST NEB TO CENTRAL KS SHOULD
MAKE A PUSH NORTHEAST INTO THE CWA DURING THE NEXT SEVERAL
HOURS...GENERALLY TIED TO MODEST ISENTROPIC LIFT EVIDENT ON THE
310K SURFACE PER THE 12Z NAM. HOWEVER...RADAR TRENDS SUGGEST THE
HRRR MAY BE A BIT AGGRESSIVE WITH HOW QUICKLY THIS LIGHT ACTIVITY
MOVES NORTHEAST. AS FOR THUNDER CHANCES...DESPITE A FEW STRIKES
RECENTLY NOTED A FEW COUNTIES SOUTHWEST OF THE CWA...AND THE
PRESENCE OF MAYBE UP TO A FEW HUNDRED J/KG ELEVATED MUCAPE...WILL
CONTINUE TO LEAVE A FORMAL THUNDER MENTION OUT OF THE AFTERNOON
GRIDS...ALTHOUGH SUPPOSE A FEW STRIKES CANNOT BE RULED OUT
ESPECIALLY FAR SOUTHWEST. TEMP WISE...MADE ONLY MINOR TWEAKS TO
AFTERNOON HIGHS...GENERALLY LOWERING WESTERN AREAS A FEW DEGREES
UNDER THE THICKEST CLOUDS...AND RAISING FAR EASTERN COUNTIES A FEW
DEGREES...WHERE QUITE A BIT OF FILTERED SUNSHINE STILL EXISTS.
ALSO TRIMMED DOWN SMALL AREA OF 80+ DEGREES IN KS ZONES TO UPPER
70S...WHICH MAY STILL BE TOO WARM. EAST TO SOUTHEAST BREEZES WILL
BE ON THE INCREASE THIS AFTERNOON...WITH ALL AREAS EXPECTED TO
OBSERVE GUSTS AT LEAST INTO THE 20-25 MPH RANGE BY DAYS END.
&&
.AVIATION...18Z KGRI TAF. OVERALL THEME OF PREVIOUS FORECAST
REMAINS INTACT...WITH VFR VISIBILITY/CEILING PREVAILING THROUGH AT
LEAST THE FIRST 12-18 HOURS OF THE PERIOD...AND THEN INCREASING
CHANCES FOR AT LEAST MVFR CEILING/VSBY ALONG WITH
SHOWERS/THUNDERSTORMS DURING THE LAST 6-8 HOURS OF THE PERIOD ON
FRIDAY MORNING AS A COMPACT...BUT STRONG LOW PRESSURE SYSTEM
ENTERS THE REGION. STARTING OFF WITH THIS AFTERNOON/THIS
EVENING...A FAIRLY SOLID MID LEVEL VFR CLOUD DECK WILL REMAIN IN
PLACE...BUT WITH ONLY SPOTTY COVERAGE OF LIGHT RAIN SHOWERS
EXPECTED...WILL ONLY CARRY A VICINITY SHOWER MENTION FOR NOW. MUCH
OF THE 00Z-10Z TIME FRAME SHOULD THEN REMAIN LARGELY PRECIPITATION
FREE...BEFORE THE MAIN PUSH OF SHOWERS/STORMS OVERSPREADS THE AREA
FROM THE SOUTHWEST IN THE 10Z-18Z TIME FRAME. ALTHOUGH CONFIDENCE
IS LOW IN CEILING/VISIBILITY DETAILS...AT LEAST LOW-END MVFR
CATEGORIES ARE ANTICIPATED. CONFIDENCE IS RATHER HIGH IN
SHOWERS/STORMS OCCURRING OFF AND ON FOR SEVERAL HOURS...AND THUS
HAVE ALREADY OPTED FOR THE INTRODUCTION OF TEMPO GROUPS. ALTHOUGH
THE RISK FOR LARGE HAIL AND/OR DAMAGING WIND GUSTS APPEARS SMALL
AT KGRI...SOME STORMS COULD CERTAINLY HAVE SMALL HAIL POTENTIAL.
AS FOR SURFACE WINDS...AN EASTERLY DIRECTION WILL DOMINATE THE
ENTIRE PERIOD...WITH SPEEDS INCREASING WITH TIME...AND FREQUENT
GUSTS OF 25-30KT.
&&
.PREV DISCUSSION... /ISSUED 410 AM CDT THU APR 26 2012/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT. PRIMARY FORECAST
CONCERN LIES WITH PRECIPITATION CHANCES...ESP TONIGHT THROUGH
FRIDAY.
CONDITIONS HAVE BEEN QUIET ACROSS THE CWA THROUGH THE
OVERNIGHT/EARLY MORNING HOURS...WITH SATELLITE AND PROFILER DATA
CONTINUING TO SHOW THE PLAINS UNDER THE INFLUENCE OF NORTHWESTERLY
FLOW. WEAK RIDGING REMAINS OVER THE HIGH PLAINS...WILE A TROUGH
SHIFTS EAST ACROSS THE GREAT LAKES AND MIDWEST. FURTHER WEST...THE
NEXT WEATHER SYSTEM TO IMPACT THE REGION CAN BE EASILY PICKED OUT
ON SATELLITE IMAGERY...A POTENT UPPER LEVEL LOW PRESSURE SYSTEM
CURRENTLY MOVING ONTO THE SOUTHERN COAST OF CAL. AT THE
SURFACE...SEEING A WEAK FRONTAL BOUNDARY PUSH SOUTH THROUGH THE
REGION ASSOCIATED WITH HIGH PRESSURE CENTERED OVER NC
CANADA...BRINGING LIGHT NORTHERLY TO VARIABLE WINDS TO THE CWA.
EVEN THOUGH WE ARE TALKING A MATTER OF 12 HRS OR SO...STILL SOME
UNCERTAINTY WITH PRECIPITATION CHANCES DURING THE DAYTIME HOURS
TODAY. THE UPPER LEVEL LOW PRESSURE SYSTEM CURRENTLY OVER THE SRN
CAL COAST WILL CONTINUE PUSHING EAST TODAY...AND BY THIS EVENING
IS EXPECTED TO END UP OVER THE FOUR CORNERS REGION. OUT AHEAD OF
THIS MAIN LOW...A WEAK MID LEVEL PIECE OF ENERGY IS EXPECTED TO
SHIFT OUT OF THE ROCKIES...POTENTIALLY BRINGING SOME PRECIP TO
PORTIONS OF THE CWA. MODELS ARENT IN THE BEST OF AGREEMENT...WITH
THE LATEST NAM SHOWING ABSOLUTELY NOTHING THROUGH 00Z...WHILE
OTHERS INCLUDING THE GFS/EC/HRRR SHOWING AT LEAST SOME SCT QPF
AROUND...MAINLY ACROSS THE WRN HALF OF THE CWA. ENDED UP NOT
MAKING NOTABLE CHANGES TO THE LOW POPS FOR TODAY...WASNT GOING TO
RAISE THEM...THE OVERALL COVERAGE /IF IT HAPPENS AT ALL/ OF PRECIP
SHOULD BE PRETTY SCATTERED. ALSO LEFT AS SHOWERS...MODELS CONTINUE
TO SHOW INSTABILITY ACROSS THE AREA BEING PRETTY MEAGER. LOOKING
AT THE SURFACE...THE MAIN AXIS OF HIGH PRESSURE OVER THE AREA THIS
MORNING SLIDES EAST THROUGH THE DAY...WHILE LOW PRESSURE IS
DEVELOPING OVER THE ROCKIES/HIGH PLAINS AHEAD OF THE UPPER LEVEL
LOW. THIS WILL BRING WINDS GRADUALLY BECOMING MORE
EAST/SOUTHEASTERLY THROUGH THE DAY...AND INCREASING IN SPEED AS
THE PRESSURE GRADIENT TIGHTENS UP ACROSS THE REGION. FORECAST
HIGHS FOR TODAY REMAIN IN THE 70S.
BY LATE THIS AFTERNOON AND THIS EVENING...THE MAIN SFC DRYLINE
BOUNDARY IS EXPECTED TO LIE THROUGH THE CENTRAL/SRN HIGH
PLAINS...AND WILL BE THE INITIAL FOCUS FOR THUNDERSTORM
DEVELOPMENT. MODEL TRENDS HAVE SLOWED THINGS DOWN/SHIFTED
W/SW...AND KEEPS THE MAIN INSTABILITY AXIS OVER FAR SRN/WRN KS
INTO OK/TX. THE MAIN QUESTION OVERNIGHT IS HOW QUICKLY ACTIVITY
PUSHES INTO THE CWA. WITH THE SLOWER TREND TO THE MODELS...DID
MAKE TIMING ADJUSTMENTS TO THE POPS...INCLUDING BACKING OFF FOR
MOST LOCATIONS BETWEEN 00-06Z THIS EVENING. WONT BE SURPRISED IF
THE DAYSHIFT NEEDS TO MAKE ADDITIONAL TWEAKS ONCE THE 12Z DATA
COMES IN. AT THIS POINT...THE BEST CHANCES FOR PRECIP LOOK TO COME
POST 06Z...WITH BETTER MODEL AGREEMENT SHOWING THE OVERALL
COVERAGE EXPANDING ACROSS THE CWA AS ASCENT INCREASES WITH THE
APPROACHING UPPER LEVEL LOW AND DEVELOPMENT OF A 40-50KT LLJ.
BETTER INSTABILITY GRADUALLY MAKES ITS WAY INTO THE CWA
OVERNIGHT...AND WHILE THE HIGH PLAINS LOOK TO SEE THE BETTER
CHANCES FOR STRONG/SEVERE THUNDERSTORMS...CERTAINLY CANT RULE IT
OUT FOR OUR CWA.
BY 12Z FRIDAY...MODELS HAVE COME INTO BETTER AGREEMENT WITH THE
PLACEMENT OF THE UPPER LEVEL LOW...SET UP NEAR THE NWRN KS/NERN CO
BORDER. THROUGH THE DAY...THIS FEATURE SHIFTS EAST...ENDING UP
OVER PORTIONS OF CTRL/ERN NEB BY THIS EVENING. THE LATEST RUNS
OF A FEW OF THE MODELS ARE TRYING TO OPEN THE LOW UP AS IT SHIFTS
THROUGH THE REGION...SHOWING IT STARTING TO PHASE IN WITH ANOTHER
LOW PRESSURE SYSTEM MOVING INTO THE NRN ROCKIES. AS FAR AS THE SFC
PATTERN GOES...THERE IS BETTER AGREEMENT SHOWING THE MAIN LOW
CROSSING EAST RIGHT OVER/JUST SOUTH OF THE NEB STATE LINE...AND IS
ALSO A TOUCH SLOWER. THE ACCOMPANYING FRONT GRADUALLY MAKES ITS
WAY THROUGH THE CWA...STILL AFFECTING CNTRL/ERN PORTIONS OF THE
CWA DURING THE AFTERNOON HOURS. STILL EXPECTING A FAIRLY NARROW
BAND OF INCREASED INSTABILITY TO DEVELOP AHEAD OF THE FRONT...BUT
THERE ARE DIFFERENCES WITH HOW FAR NORTH THROUGH THE CWA IT WILL
EXTEND. STILL A CONCERN FOR A FEW STRONG/SEVERE THUNDERSTORMS AS
THE MID/UPPER LEVEL SYSTEM PUSHES THROUGH AND WITH THE SFC
LOW/FRONTS IN THE AREA...WITH THE BETTER CHANCES LOOKING TO AFFECT
THE SRN HALF OF THE CWA. THE HIGH TEMPERATURE FORECAST REMAINS
TRICKY...BEING DEPENDENT ON THE TIMING/LOCATION OF THE MAIN BAND
OF PRECIP THROUGH THE DAY. COULD END UP WITH A 15-20 DEGREE
GRADIENT ACROSS THE CWA...WITH LOWER 50S IN THE NORTHEAST WITH THE
PRECIP/CLOUDS...VS LOWER 70S IN THE SOUTH WHICH COULD SEE A FEW
PEAKS OF SUN DURING THE AFTERNOON. AND WITH MORNING LOWS ALREADY
IN THE 50S...THOSE NORTHERN LOCATIONS LIKELY WONT SEE MUCH CHANGE
IN TEMPS THROUGH THE DAY. WILL CONTINUE TO BE A BREEZY DAY...WITH
E/SERLY WINDS TO START THE DAY...SWITCHING TO THE NW BEHIND THE
FRONT. SUSTAINED SPEEDS OF 20+ MPH EXPECTED...AT TIMES SOME
LOCATIONS COULD FLIRT WITH ADVISORY CRITERIA...WILL BE SOMETHING
TO KEEP AN EYE ON.
THROUGH THE EVENING HOURS...THE MAIN AREA OF PRECIP CONTINUES
TO SWING E/NE...AND DIDNT MAKE BIG CHANGES TO THE 00-06Z
POPS...BUT DID CUT BACK POST 06Z. EXPECTING THAT BY 09Z OR SO
PRECIP WILL HAVE SHIFTED OUT OF THE CWA.
KEPT THE DRY FORECAST GOING THROUGH THE DAYTIME AND EVENING HOURS
ON SATURDAY...WITH THE REGION SITTING UNDER ZONAL UPPER LEVEL
FLOW...DOMINATED BY A LOW PRESSURE SYSTEM SET UP OVER THE NRN
ROCKIES/HIGH PLAINS. HIGH PRESSURE SETS UP OVER THE REGION BEHIND
THE FRONT...WHICH WILL BRING DIMINISHING SPEEDS...AND WITH A
COOLER AIR MASS IN PLACE...HIGHS ARE EXPECTED TO TOP OUT IN THE
LOW/MID 60S. WILL CONTINUE TO CARRY SMALL POPS ACROSS THE WEST
AFTER MIDNIGHT...AS A PIECE OF ENERGY ASSOCIATED WITH THAT MAIN
UPPER LEVEL LOW PRESSURE SYSTEM SWINGS THROUGH THE AREA.
LONG TERM...STARTING 12Z SUNDAY...A FAIRLY UNSETTLED WEATHER
PATTERN APPEARS TO BE IN STORE FOR THE LOCAL AREA THROUGH THE
EXTENDED PERIODS AS VARIABLE CHANCES FOR SHOWERS OR THUNDERSTORMS
ARE POSSIBLE EACH DAY. TEMPERATURES WILL START OFF SUNDAY SEVERAL
DEGREES BELOW CLIMO AS A COOL AIRMASS WILL REMAIN IN PLACE ACROSS
THE REGION IN WAKE OF DEPARTING UPPER LEVEL LOW...WITH A GRADUAL
WARMING TREND THEN EXPECTED THROUGH THE MIDDLE OF NEW WEEK.
THROUGH THE PERIOD...A FAIRLY PROGRESSIVE WESTERLY UPPER LEVEL
FLOW PATTERN APPEARS TO BE SETTING UP ACROSS THE REGION...WITH
GOOD AGREEMENT AMONG BOTH THE LATEST GFS AND EC DEVELOPING THIS
FLOW PATTERN. WHILE SHOWER AND THUNDERSTORM CHANCES WILL VARY
GREATLY WITH TIMING OF EACH PASSING WAVE...AT THIS TIME...CHANCES
APPEAR TO INCREASE EARLY NEXT WEEK AS LOW LEVEL FLOW TURNS MORE
SOUTHERLY AND INCREASES DEWPOINTS ACROSS THE REGION. THIS
INCREASED LOW LEVEL MOISTURE WILL AID IN CONVECTIVE INSTABILITY BY
MONDAY AFTERNOON...WITH MU CAPE VALUES SURGING ACROSS THE LOCAL
AREA. WHILE THE SHEAR PROFILE IS NOT IDEAL...WITH SO MUCH
INSTABILITY CANNOT RULE OUT THE CHANCE OF A STRONG OR EVEN SEVERE
THUNDERSTORM OVER THIS TIME PERIOD...AND CORRESPONDINGLY DECIDED
TO ADVERTISE THE POTENTIAL IN MORNING HWO.
WHILE CONVECTIVE POTENTIAL INCREASES BY MONDAY...WETTEST DAY
ACTUALLY APPEARS TO BE SUNDAY...AS CLOUDY SKIES AND STRATIFORM
PRECIP ARE EXPECTED THANKS TO A LARGE UPPER LEVEL LOW ACROSS THE
NORTHERN ROCKIES AND ITS ASSOCIATED FRONTAL BOUNDARY DRAPED ACROSS
THE LOCAL AREA. AT THIS TIME...INSTABILITY IS VERY LIMITED ON
SUNDAY...AND DECIDED NOT TO INCLUDE THE MENTION OF THUNDERSTORM
ACTIVITY UNTIL INSTABILITY INCREASES SIGNIFICANTLY ON MONDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/UPDATE...PFANNKUCH
SHORT TERM...ADO
LONG TERM...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1235 AM CDT THU APR 26 2012
.AVIATION...06Z KGRI TAF...CLOUDS WILL THICKEN OVER THE NEXT 24
HOURS AND WINDS WILL INCREASE AND SHIFT SOUTHEASTERLY THROUGH THE
DAY ON THURSDAY...WITH VFR CONDS EXPECTED TO HOLD THROUGH THE
PERIOD. ALREADY SEEING SIGNIFICANT HIGH CLOUD COVER ADVECTING
ACROSS THE LOCAL AREA EARLY THIS MORNING...WITH CIGS EXPECTED TO
LOWER GRADUALLY OVER THE NEXT 12-18 HOURS AS AN AREA OF LOW
PRESSURE ACROSS THE WEST COAST BEGINS TO LIFT NORTHEASTWARD
TOWARDS THE LOCAL AREA. WENT AHEAD A INTRODUCED A VCSH AFT 26/23Z
ALONG WITH CIGS AROUND 5KFT...BUT THINK BETTER CHANCE FOR SHOWER
AND THUNDERSTORM ACTIVITY LIES JUST BEYOND CURRENT VALID PERIOD OF
TAF...AND LEFT OUT PREVAILING PRECIP AND MVFR CIGS AT THIS TIME.
EASTERLY WINDS AROUND 8-10KTS ARE EXPECTED TO DEVELOP ACROSS THE
LOCAL AREA AROUND DAYBREAK THURSDAY...STEADILY INCREASING AND
BECOMING MORE SOUTHEASTERLY AS WE HEAD TOWARDS AFTERNOON HOURS AS
THE PRESSURE GRADIENT BEGINS TO TIGHTEN ACROSS THE REGION AHEAD OF
THE APPROACHING DISTURBANCE.
&&
.PREV DISCUSSION... /ISSUED 405 PM CDT WED APR 25 2012/
SHORT TERM...THROUGH THURSDAY AFTERNOON. PRIMARY CONCERN IN THE
NEXT 24 HOURS IS HOW MUCH OF THE CWA STANDS TO SEE MEASURABLE
RAINFALL...AND THE MAIN THEME HERE IS THAT THESE CHANCES CONTINUE
TO DECREASE IN MOST AREAS...WITH MUCH BETTER CHANCES HOLDING OFF
UNTIL THE THURSDAY NIGHT PERIOD AS DISCUSSED IN THE LONG TERM
SECTION BELOW. ALSO...ALL MENTION OF THUNDERSTORMS HAS BEEN PULLED
THROUGH THURSDAY AFTERNOON THANKS TO VERY MEAGER INSTABILITY.
19Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK 1000MB LOW OVER
CENTRAL IA...WITH A TROUGH AXIS/WEAK COLD FRONT TRAILING
SOUTHWESTWARD ACROSS EASTERN/SOUTH CENTRAL KS. IN THE WAKE OF THIS
BOUNDARY...NORTH BREEZES GUSTING TO AROUND 30 MPH AND LOCALLY
HIGHER HAVE BEEN COMMON ACROSS THE CWA THIS AFTERNOON. DESPITE
NEUTRAL TO EVEN WEAK COLD AIR ADVECTION EVIDENT AT 850MB...TEMPS
HAVE AGAIN SOARED TO AT LEAST NEAR-RECORD LEVELS IN MANY
CENTRAL/SOUTHERN COUNTIES THANKS TO DEEP MIXING INTO THE
750-700MB RANGE PER FORECAST SOUNDINGS. SLIGHTLY COOLER TEMPS HAVE
TAKEN HOLD IN THE NORTHWESTERN CWA...RESULTING IN A RANGE FROM
LOW-MID 80S NORTHWEST TO MAINLY LOW 90S SOUTHEAST. UNLIKE
YESTERDAY..IT APPEARS TRI-CITIES TEMP RECORDS FOR THE DAY ARE
LIKELY SAFE. LOOKING ALOFT...WATER VAPOR IMAGERY AND SHORT TERM
MODEL DATA CONFIRM A BROAD RIDGE CENTERED OVER THE ROCKIES...WITH
AN UPSTREAM TROUGH AND CLOSED 500MB LOW APPROACHING THE SOUTHERN
CAL COAST. A SUBTROPICAL MOISTURE PLUME IN THE MID/UPPER LEVELS IS
RIDING AROUND THE TOP OF THE RIDGE AND HAS RESULTED IN A FAIRLY
THICK BUT NARROW PLUME OF CIRRUS OVERSPREADING MUCH OF THE
SOUTHWEST 1/2 OF THE CWA TODAY. MEANWHILE...SOME HIGH BASED
CUMULUS AND EVEN SOME WEAK THUNDERSHOWERS ARE POPPING AT THIS HOUR
ALONG AN AXIS FROM THE WESTERN NEBRASKA SANDHILLS BACK UP INTO THE
BLACK HILLS.
LATE THIS AFTERNOON THROUGH AT LEAST MIDNIGHT...THE VAST
MAJORITY...IF NOT THE ENTIRE CWA WILL STAY DRY AS THE AIRMASS OVER
THE LOCAL AREA IS QUITE CAPPED TO LOW-LEVEL PARCELS. HOWEVER...AM
A BIT WARY THAT A LIGHT SHOWER OR MAYBE EVEN A WEAKENING
THUNDERSTORM OR TWO COULD TRY MAKING AN RUN AT A FEW OF THE
NORTHWEST COUNTIES IN THE 22Z-02Z TIME FRAME...AS ACTIVITY
DEVELOPING IN THE VERY STEEP LOW LEVEL LAPSE RATE ENVIRONMENT OFF
THE SANDHILLS DRIFTS SOUTHEAST. THIS ACTIVITY IS WELL CAPTURED BY
THE LATEST HRRR RUNS...BUT EVEN THIS MODEL...WHICH IS MOST
AGGRESSIVE WITH THIS ACTIVITY FADES MOST OF IT OUT BEFORE IT
ENTERS THE NORTHWEST COUNTIES. EVENING SHIFT WILL HAVE TO KEEP AN
EYE ON THIS...BUT AM GOING TO ONLY GO WITH A SLIGHT CHANCE
SPRINKLE MENTION FOR NOW...AND ASSUME THAT ANY HEAVIER SHOWERS OR
WEAK THUNDERSTORMS LOSE STEAM BEFORE THEY WOULD GET IN. TURNING TO
THE POST-MIDNIGHT HOURS...PULLED THUNDERSTORM MENTION
ALTOGETHER...AND EVEN PULLED MEASURABLE POPS...LEAVING ONLY A
SLIGHT CHANCE SPRINKLE MENTION IN FAR WESTERN COUNTIES AFTER 08Z.
INSTABILITY IS VIRTUALLY NON-EXISTENT LATE TONIGHT...AND THE ONLY
FORCING FOR PRECIP WILL BE A GRADUAL MID-LEVEL TOP-DOWN MOISTENING
FROM WEST TO EAST EVIDENT IN THE DEWPOINT AND RH FIELD AT 700MB ON
MODELS SUCH AS THE 12Z NAM. BETTER CHANCES FOR MEASURABLE LIGHT
SHOWERS LATE TONIGHT WILL CERTAINLY RESIDE JUST WEST OF THE CWA
OVER THE GLD FORECAST AREA. OTHERWISE...WINDS THIS EVENING WILL
QUICKLY DIMINISH...WITH LIGHT FLOW GRADUALLY TURNING FROM
NORTHERLY TO EASTERLY AS A SURFACE RIDGE AXIS CENTERED WELL TO THE
NORTH MIGRATES EASTWARD. CHANGED LOW TEMPS LITTLE FROM PREVIOUS
FORECAST...AND WITH MID LEVEL CLOUDS ON THE INCREASE...WILL KEEP
THINGS GENERALLY 2-3 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...BOTTOMING OUT MOST OF THE CWA BETWEEN 54-58 DEGREES.
ON THURSDAY...THE HEART OF THE MID/UPPER RIDGE AXIS WILL PASS
OVERHEAD...AS THE UPSTREAM COMPACT BUT STRONG CLOSED LOW GRADUALLY
MIGRATES FROM NEAR THE FAR SOUTHERN TIP OF CAL AT 12Z TO NEAR THE
4-CORNERS BY 00Z. WITH THIS FEATURE REMAINING WELL OFF TO THE
SOUTHWEST OF THE CWA...APPRECIABLE FORCING WILL REMAIN
WEAK...DESPITE INCREASING MID/HIGH LEVEL CLOUD COVER AND WEAK
FORCING ASSOCIATED WITH A SUBTLE LEAD WAVE. THE 12Z NAM WAS QUITE
SUPPORTIVE OF PULLING THUNDER MENTION...WITH EVEN ELEVATED CAPE
NEGLIGIBLE. HOWEVER...WILL FOLLOW NAM SOLUTION FAIRLY CLOSELY...WITH
BEST CHANCE FOR LIGHT SHOWERS FOCUSED ACROSS THE NORTHWEST 1/4 OF
THE CWA AS WEAK LIFT FROM THE LEAD SHORTWAVE KEEPS MID LEVEL
THETA-E ADVECTION ALIVE. EVEN OUTSIDE THIS MOST FAVORED
AREA...KEPT AT LEAST A SLIGHT CHANCE POP OR A SPRINKLE MENTION
GOING CWA-WIDE ESPECIALLY DURING THE AFTERNOON...BUT WOULD BE
SURPRISED TO SEE MOST AREAS MEASURE MORE THAN A FEW HUNDREDTHS OF
AN INCH...AND A GOOD PERCENTAGE OF THE AREA LIKELY STAYING DRY.
TEMPS WILL BE A BIT TRICKY...WITH PLENTIFUL CLOUD COVER AND
INCREASING EASTERLY WINDS INTO THE 15-20 MPH RANGE DURING THE
AFTERNOON. IT WILL CERTAINLY BE COOLER THAN THESE PAST FEW DAYS
THOUGH. OPTED TO MAKE LITTLE CHANGE TO PREVIOUS FORECAST...AND
DIDN/T STRAY MORE THAN A FEW DEGREES FROM MET/MAV GUIDANCE
CONSENSUS...RESULTING IN A RANGE FROM LOW-MID 70S IN NEB
ZONES...TO MID-UPPER 70S IN KS ZONES. THESE HIGHS COULD EASILY BE
OFF A BIT THOUGH BASED ON CLOUD/PRECIP TRENDS OR LACK THEREOF.
LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY. BEGINNING THE MID
TERM PERIOD...THE UPPER LEVEL RIDGE WHICH BROUGHT WARM
TEMPERATURES AND RECORD HIGHS TO THE PLAINS WILL BEGIN TO BREAK
DOWN...MAINLY DUE TO AN UPPER LEVEL TROUGH PUSHING ACROSS THE WEST
COAST. AHEAD OF THIS TROUGH...A BURST OF TROUGH ENERGY IN THE FORM
OF A SHORT WAVE/CLOSED LOW WILL BEGIN TO SLIDE THROUGH THE PLAINS
THURSDAY NIGHT INTO FRIDAY.
AS LOW PRESSURE DEVELOPS ALONG THE FRONT RANGE OF THE ROCKIES...AN
INCREASED PRESSURE GRADIENT WILL HELP INCREASE EASTERLY WINDS
OVERNIGHT THURSDAY. A SURGE OF MOISTURE WILL MOVE INTO THE PLAINS
OVERNIGHT...AND COMBINED WITH UPPER LEVEL FORCING AND ISENTROPIC
LIFT...CREATE A GOOD CHANCE FOR PRECIPITATION DURING THE OVERNIGHT
HOURS ON THURSDAY...ESPECIALLY AFTER MIDNIGHT. THUNDERSTORM CHANCES
CERTAINLY REMAIN POSSIBLE ESPECIALLY ACROSS THE SOUTHWEST PORTIONS
OF THE FORECAST AREA BEFORE MIDNIGHT AS THE THE DRY LINE MIXES
EASTWARD. CANNOT RULE OUT A STRONG TO SEVERE THUNDERSTORM ACROSS THE
SOUTHEAST...DEPENDENT UPON WHERE THE DRY LINE SETS UP. AFTER
MIDNIGHT AND THROUGH THE DAY ON FRIDAY...BOTH THE GFS AND THE ECMWF
SOLUTION KEEP THE SURFACE LOW WELL TO THE SOUTH OF THE FORECAST
AREA...THUS KEEPING MUCH OF THE MAIN INSTABILITY AXIS TO THE SOUTH.
THE NAM SOLUTION IS A BIT TRICKIER AND KEEPS THE LOW SLIGHTLY
FURTHER NORTH. A LARGE AREA OF WRAP AROUND MOISTURE WILL INFILTRATE
THE PLAINS...FUELED BY GOOD ISENTROPIC LIFT AND UPPER LEVEL
DIFFLUENCE. AT THIS TIME...GIVEN THE DIFFERENCE IN SOLUTIONS...CANNOT
RULE OUT ISOLATED THUNDERSTORM CHANCES THROUGH THE DAY ON FRIDAY.
THE UPPER LEVEL SHORT WAVE BEGINS TO KICK OFF TO THE EAST BY
SATURDAY MORNING...WITH LINGERING POPS ACROSS THE NORTHWEST.
SATURDAY LOOKS TO BE PRECIPITATION FREE...WITH PARTLY CLOUDY SKIES.
AS A RESULT...DECIDED TO UP TEMPERATURES SLIGHTLY ACROSS THE
REGION...WITH MID 60S EXPECTED.
THE MAIN UPPER LEVEL LOW FINALLY SHIFTS NORTHWARD BY SUNDAY EVENING.
HOWEVER...NUMEROUS MID LEVEL SHORT WAVES CONTINUE TO IMPACT THE
PLAINS THROUGH THE LONG TERM PERIOD. SEVERAL SURFACE LOWS DEVELOP
ALONG THE FRONT RANGE...PROVIDING SEVERAL CHANCES FOR RAIN SHOWERS
THROUGH THE PERIOD.
SPECIFICALLY...MONDAY NIGHT THROUGH TUESDAY...AN AREA OF UPPER LEVEL
POSITIVE VORTICITY COMBINED WITH SURFACE LOWS WILL BRING A DECENT
SHOT OF RAIN SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA.
INSTABILITY PARAMETERS SUGGEST MUCAPES NEAR 500 J/KG. AT THIS
TIME...CANNOT RULE OUT A STRONG THUNDERSTORM OR TWO.
WHILE THE WEEKEND WILL BE FAIRLY COOL...WITH HIGHS IN THE UPPER 50S
TO LOWER 60S...WARMER TEMPERATURES RETURN TO THE FORECAST AREA BY
TUESDAY...WITH LOWER 70S EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
955 PM EDT FRI APR 27 2012
.SYNOPSIS...
MAINLY CLEAR SKIES OVERNIGHT 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 SATURDAY/...
945 PM UPDATE...SKIES ACROSS MUCH OF THE AREA HAVE CLEARED THIS
EVENING UNDER DRY NORTHWEST FLOW. MOSTLY CLOUDY SKIES STILL
HOLDING TUFF OVER THE NORTHERN FORECAST AREA BUT CURRENT SATELLITE
PICS SHOW CLEARING SKIES OVER EASTERN LAKE ONTARIO. THIS WILL LEAD
TO PARTLY TO MAINLY CLEAR CONDITIONS FOR ONONDAGA, ONEIDA AND
MADISON COUNTIES AROUND MIDNIGHT. TEMPS CURRENTLY RANGE IN THE
LOWER TO MIDDLE 30S AND WITH MAINLY CLEAR SKIES FOR MUCH OF THE
OVERNIGHT PERIOD CURRENT MIN TEMP FORECAST IN THE MID TO UPPER
20S LOOKS REASONABLE. FREEZE WARNING CONTINUED. JUST MINOR SHORT
TERM ADJUSTMENTS TO TEMPS AND CLOUDS.
PREVIOUS AFD...
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 NIGHT 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 CONTINUANCE OF
THE FREEZE WARNING
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
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 /02Z SATURDAY THROUGH WEDNESDAY/...
LATEST SATELLITE TRENDS SHOWING CONSIDERABLE CLEARING ACROSS
CENTRAL NY AND NE PA THIS EVENING IN RESPONSE TO SFC HIGH PRESSURE
BEGINNING TO EXTEND INTO THE REGION. EXPECT THIS TREND TO
CONTINUE THROUGH THE REMAINDER OF THE EVENING WITH ALL SITES
BECOMING SKC BY 04/05Z TIMEFRAME. BEYOND THIS...UPPER CI CURRENTLY
NOTED ACROSS THE WESTERN GREAT LAKES AND OHIO VLY WILL WORK INTO
THE AREA TOWARDS MORNING...BEFORE GROWING MORE DENSE THROUGH THE
DAY. EXPECT THE LOWEST CIGS AT AVP TOWARDS THE CONCLUSION OF THE
PERIOD AS SFC LOW PRESSURE SKIRTS ACROSS SOUTHERN PA. FCST
SOUNDINGS SUGGEST POTENTIAL FOR DEVELOPING SHRA AT AVP BY EARLY
EVENING...HOWEVER RESTRICTIONS ARE NOT EXPECTED UNTIL AFTER 00Z
SUN.
.OUTLOOK...
SAT NGT...MAINLY VFR AT CNY SITES WITH POSSIBLE MVFR AT AVP IN
DEVELOPING SHRA/SHSN.
SUN-MON...VFR.
TUE INTO WED...RESTRICTIONS POSSIBLE IN POSSIBLE -SHRA ACTIVITY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZE WARNING UNTIL 9 AM EDT SATURDAY FOR PAZ038>040-043-044-
047-048-072.
NY...FREEZE WARNING UNTIL 9 AM EDT SATURDAY FOR NYZ009-015>018-
022>025-036-037-044>046-055>057-062.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/RRM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
749 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 SATURDAY/...
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 NIGHT 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 CONTINUANCE OF
THE FREEZE WARNING
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
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 /00Z SATURDAY THROUGH WEDNESDAY/...
LATEST SATELLITE TRENDS SHOWING CONSIDERABLE CLEARING ACROSS
CENTRAL NY AND NE PA THIS EVENING IN RESPONSE TO SFC HIGH PRESSURE
BEGINNING TO EXTEND INTO THE REGION. EXPECT THIS TREND TO
CONTINUE THROUGH THE REMAINDER OF THE EVENING WITH ALL SITES
BECOMING SKC BY 04/05Z TIMEFRAME. BEYOND THIS...UPPER CI CURRENTLY
NOTED ACROSS THE WESTERN GREAT LAKES AND OHIO VLY WILL WORK INTO
THE AREA TOWARDS MORNING...BEFORE GROWING MORE DENSE THROUGH THE
DAY. EXPECT THE LOWEST CIGS AT AVP TOWARDS THE CONCLUSION OF THE
PERIOD AS SFC LOW PRESSURE SKIRTS ACROSS SOUTHERN PA. FCST
SOUNDINGS SUGGEST POTENTIAL FOR DEVELOPING SHRA AT AVP BY EARLY
EVENING...HOWEVER RESTRICTIONS ARE NOT EXPECTED UNTIL AFTER 00Z
SUN.
.OUTLOOK...
SAT NGT...MAINLY VFR AT CNY SITES WITH POSSIBLE MVFR AT AVP IN
DEVELOPING SHRA/SHSN.
SUN-MON...VFR.
TUE INTO WED...RESTRICTIONS POSSIBLE IN POSSIBLE -SHRA ACTIVITY.
&&
.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...CMG
AREA FORECAST DISCUSSION
NWS BUFFALO NY
149 AM EDT THU APR 26 2012
.SYNOPSIS...
HIGH PRESSURE THAT BROUGHT DRY CONDITIONS AND A FAIR AMOUNT OF
SUNSHINE TO THE AREA WILL SLIDE OFF THE EAST COAST TONIGHT. LOW
PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL PASS JUST SOUTH OF
NEW YORK STATE ON THURSDAY AND BRING A GOOD CHANCE FOR SHOWERS.
A NORTHWEST FLOW OF CHILLY AIR WILL FOLLOW ON FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
A RIDGE OF HIGH PRESSURE WILL SLIDE OFF THE EAST COAST OVERNIGHT AS
LOW PRESSURE MOVES EAST FROM IOWA AND REACH THE VICINITY OF
CENTRAL OHIO BY 12Z THURSDAY. MID LEVEL CLOUDS WILL INCREASE
ACROSS OUR CWA OVERNIGHT AS THIS SYSTEMS APPROACHES.
MEANWHILE...LOW CLOUDS HAVE MOVED FURTHER EAST OF LAKE
ONTARIO...WHICH WILL ALLOW A PERIOD OF CLEAR SKIES AND LIGHT
WINDS. WHILE STILL MARGINAL...DO EXPECT FROST TO DEVELOP IN THIS
NARROW WINDOW OF OPPORTUNITY EAST OF LAKE ONTARIO...WITH LOWS
AROUND FREEZING. WILL GO WITH A BRIEF FROST ADVISORY FOR
OSWEGO/JEFFERSON/LEWIS COUNTIES. THIS SHOULD HAVE A MODEST
IMPACT...WITH BRIEF AND NEAR FREEZING TEMPERATURES IMPACTING THE
SENSITIVE VEGETATION. ELSEWHERE...HIGH CLOUDS AND AN INCREASING SE
FLOW WILL CAUSE TEMPERATURES TO HOLD STEADY...AND EVENTUALLY RISE
IN FAR WESTERN SECTIONS TOWARD DAYBREAK.
OTHERWISE...RADAR SHOWS THAT SHOWERS ASSOCIATED WITH THE
APPROACHING LOW ARE QUITE CONVECTIVE IN NATURE. BOTH MODEL AND
RADAR TRENDS SUGGEST A SLIGHTLY SLOWER START TIME...AS SHOWERS
CONTINUE TO SLIDE TO THE SE ON A TRAJECTORY TO STAY SOUTH OF THE
CWA. 00Z RUNS OF THE NAM/RGEM AND THE LATEST HRRR ARE ALL
DOWNPLAYING THE POTENTIAL FOR EARLY MORNING SHOWERS...WITH A MID-
TO LATE MORNING TIMING NOW APPEARING MORE LIKELY.
SHOWERS WILL EVENTUALLY MOVE INTO THE REGION THURSDAY MORNING.
INCREASING LOW LEVEL MOISTURE WILL FOCUS ALONG A SURFACE TROUGH
THAT IS FORECAST TO EXTEND NORTH OF THE PARENT LOW. THIS WILL LEAD
TO A GOOD CHANCE FOR SHOWERS...ESPECIALLY ACROSS THE NORTH COUNTRY
WHERE ADDITIONAL LIFT WILL BE GENERATED BY A POTENT SHORT WAVE AND
INCREASING WARM AIR ADVECTION. RIGHT NOW...IT LOOKS LIKE THE
STEADIEST PCPN WILL IMPACT WESTERN NEW YORK AND THE GENESEE VALLEY
LATE MORNING AND EARLY AFTERNOON...THEN SHIFT INTO THE EASTERN
FINGER LAKES AND NORTH COUNTRY DURING THE AFTERNOON HOURS. WHILE
THE CHANCES ARE MINIMAL...MODEST LEVELS OF ELEVATED INSTABILITY
SUGGEST THERE MAY BE AN ISOLATED RUMBLE OF THUNDER ACROSS THE
SOUTHERN TIER ON THURSDAY MORNING.
SOUTHERLY WINDS AHEAD OF THE SURFACE TROUGH WILL ALLOW TEMPERATURES
TO WARM WELL INTO THE 50S ON THURSDAY...BEFORE COLD AIR ADVECTION
SETS UP BEHIND THE TROUGH LATER IN THE AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW WILL BE IN THE PROCESS
OF EXITING THE AREA AT THE START OF THE PERIOD. LOW LEVEL MOISTURE
SHOULD REMAIN HIGH IN WAKE OF THE SYSTEM AND THIS COMBINED WITH
INCREASING LOW LEVEL COLD AIR ADVECTION WILL CONTINUE THE THREAT
FOR SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO DURING THE EVENING.
850 MB TEMPERATURES DROPPING TO BETWEEN -10C AND -12C COULD VERY
EASILY BRING SOME LAKE RESPONSE...ESPECIALLY EAST OF LAKE ONTARIO
AND THE WESTERN SOUTHERN TIER. BOUNDARY LAYER SHOULD GET COLDER
ENOUGH TO SEE A CHANGE OVER TO ALL SNOW OVER THE HIGHER
ELEVATIONS. MINOR ACCUMULATIONS IN THE 1 TO 2 INCH RANGE ARE
POSSIBLE. SNOW/RAIN SHOWERS WILL LIKELY LINGER FRIDAY MORNING
ACROSS EASTERN SECTIONS...BUT WITH SURFACE RIDGING AND ASSOCIATED
DRIER AIR BUILDING INTO THE REGION WE WILL SEE AN IMPROVING TREND
FOR FRIDAY. STILL PLENTY OF COLD AIR ALOFT WITH 850 MB
TEMPERATURES BETWEEN -6C TO -10C...YIELDING DAYTIME HIGHS FRIDAY
ONLY IN THE 40S.
TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING WILL BE A CONCERN.
CLEAR SKIES AND LIGHT WINDS WILL BRING WIDESPREAD FREEZE/FROST
CONCERNS.
MODEL CONSENSUS CONTINUES TO KEEP THE NORTHERN EDGE OF MOISTURE
ALONG AND NORTH OF THE APPROACH WARM FRONT LIFTING UP ACROSS THE
OHIO VALLEY TO THE SOUTH OF THE AREA FOR SATURDAY. THE GFS IS THE
FARTHER NORTH OF THE SOLUTIONS AND JUST NUDGES THE SOUTHERN TIER
WITH SOME VERY MINOR QPF...BUT THE NAM/GEM/ECMWF/SREF SOLUTIONS
ALL KEEP HOLD THE PRECIPITATION SOUTH OF THE REGION. AT THIS POINT
WILL STAY CLOSE TO MODEL CONSENSUS AND KEEP THE AREA DRY FOR
SATURDAY.
TEMPERATURES AGAIN SATURDAY NIGHT WILL BE A CONCERN...WITH
THE POTENTIAL FOR MORE FREEZE/FROST CONCERNS AS THE HIGH REMAINS
PARKED OVER THE REGION.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
LATEST MEDIUM RANGE MODELS AND ENSEMBLES CONTINUING TO SUGGEST THIS
PERIOD WILL BE COOL WITH MAINLY QUIET WEATHER. WESTERN AND CENTRAL
NEW YORK WILL REMAIN IN A NORTHWESTERLY FLOW REGIME BETWEEN
SLOWLY DEPARTING UPPER LOW SPINNING ACROSS EASTERN CANADA AND A
SLOWLY PROGRESSIVE RIDGE ACROSS CENTRAL CANADA. AT THE SURFACE...A
SPRAWLING AREA OF HIGH PRESSURE WILL SLOWLY BUILD TO THE SOUTHEAST
FROM CENTRAL CANADA...SETTLING OVER WESTERN AND CENTRAL NEW YORK
DURING THE FIRST HALF OFF THE PERIOD. WARM FRONTAL PRECIPITATION
LOOKS TO REMAIN WELL TO THE SOUTH OFF THE AREA DURING THE WEEKEND.
THE HIGH REMAINS THE DOMINANT FEATURE TUESDAY...ALTHOUGH SHIFTING
EAST OF THE REGION. THIS WILL ALLOW WARM AIR ADVECTION TO SET UP
AHEAD OF A FAST MOVING PACIFIC SHORTWAVE WEDNESDAY. WEDNESDAY LOOKS
TO HAVE THE BEST THREAT FOR PRECIPITATION AS THIS WAVE WORKS
ACROSS THE REGION. BASICALLY...WITH THE CONTINENTAL POLAR AIRMASS
REMAINING FIRMLY IN PLACE IN THE SUNDAY THROUGH TUESDAY TIME
FRAME. THERE SHOULD BE PLENTY OF SUNSHINE WITH A GRADUAL WARMING
TREND. WEDNESDAY LIKELY TO BE THE MILDEST DAY AS WARMER AIR
CONTINUES TO SPREAD INTO THE REGION IN A STRENGTHENING RETURN
FLOW.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE EXITING ACROSS NEW ENGLAND DURING THE PRE DAWN HOURS
WILL KEEP VFR CONDITIONS IN PLACE THROUGH AT LEAST LATE MORNING...
ALTHOUGH HIGH CLOUDINESS WILL THICKEN FROM WEST TO EAST. THE ONLY
PROBLEM DURING THIS PERIOD WILL BE SOME MARGINAL LOW LEVEL WIND
SHEAR CONDITIONS THAT WILL BE FOUND OVER THE WESTERN COUNTIES AS A
35KT SOUTHERLY LOW LEVEL JET WILL BE SET UP BETWEEN 1000-1500 FT.
AS THE UPCOMING AFTERNOON PROGRESSES THOUGH...AN AREA OF LOW
PRESSURE WILL PASS BY ACROSS PENNSYLVANIA. THIS WILL GENERATE A 3 TO
5 HR PERIOD OF SHOWERS THAT WILL MOVE ACROSS THE REGION WITH CIGS
DROPPING TO BETWEEN 2500-3500 FT. AS THE SHOWERS PUSH OFF TO THE
EAST THURSDAY EVENING...CIGS SHOULD BE AT MVFR LEVELS WITH WEST TO
NORTHWEST WINDS BECOMING GUSTY.
OUTLOOK...
FRIDAY...MAINLY VFR WITH CHANCE RAIN
SATURDAY...MAINLY VFR.
SUNDAY AND MONDAY...VFR.
&&
.MARINE...
LOW PRESSURE MOVING EAST FROM THE CENTRAL PLAINS WILL TRACK SOUTH
OF NEW YORK STATE THURSDAY...THEN SETTLE OFF THE EAST COAST
THURSDAY NIGHT. A BRISK WEST TO NORTHWEST FLOW IN THE WAKE OF THIS
LOW WILL LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS THURSDAY
NIGHT AND FRIDAY. HIGH PRESSURE WILL BRING QUIETER CONDITIONS
SATURDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FROST ADVISORY UNTIL 7 AM EDT THIS MORNING FOR NYZ006>008.
MARINE...NONE.
&&
$$
SYNOPSIS...TJP
NEAR TERM...APFFEL/TJP
SHORT TERM...TMA
LONG TERM...TMA
AVIATION...RSH
MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1100 PM EDT FRI APR 27 2012
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER ACROSS THE AREA OVERNIGHT BEFORE
LIFTING NORTH ON SATURDAY. WARM SOUTHWEST FLOW WILL PREVAIL
THROUGH SUNDAY BEFORE THE FRONT DROPS BACK SOUTH AND CROSSES THE
AREA SUNDAY NIGHT. RELATIVELY COOL HIGH PRESSURE WILL BRIEFLY BUILD
IN BEHIND THE FRONT MONDAY...THEN MOVE OFFSHORE TUESDAY ALLOWING
THE RETURN OF A WARM SOUTHERLY FLOW THROUGH THE REMAINDER OF THE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM EDT FRIDAY...THE INLAND PROGRESSION OF THE SEA BREEZE
AND THE COOL SURGE FROM THE NE ASSOCIATED WITH THE BACKDOOR COLD
FRONT...HAD ADVECTED A DEEP ENOUGH LOW LEVEL STABLE MARINE LAYER
ACROSS PORTIONS OF THE ILM COASTAL COUNTIES TO CAUSE THE WEAKENING
OF THE CONVECTION AS IT TRACKED TOWARD THE IMMEDIATE COAST. IN
FACT...THE MAJORITY OF THIS EVENING EXHIBITED LITTLE IF ANY
CONVECTIVE ACTIVITY MOVING OFF THE MAINLANDS OF NC OR SC.
HOWEVER...A CLUSTER OF CONVECTION JUST UPSTREAM OF THE ILM CWA...HAS
BECOME BETTER ORGANIZED THIS LATE EVENING AND IS TRAVERSING THE
EAST-WEST ORIENTED STATIONARY FRONTAL BOUNDARY. WITH THE AID OF A
S/W MID LEVEL TROF DURING THE OVERNIGHT...THIS CLUSTER SHOULD REMAIN
ORGANIZED ENOUGH TO OVERCOME THE MODIFIED SHALLOW STABLE MARINE
LAYER CLOSER TO THE COAST. BOTH THE LATEST RUC AND NAM MODELS
INDICATE DECENT UVVS GENERATED BY THIS MID LEVEL S/W TROF AS IT
TRACKS ACROSS THE ILM CWA AND OFF THE MAINLAND DURING THE OVERNIGHT.
WITH THIS SAID...HAVE INCREASED POPS ACROSS THE COASTAL COUNTIES AND
ADJACENT ATL WATERS...ESPECIALLY DURING THE PRE-DAWN SAT HRS AFTER
THE SVR WATCH WHICH ENDS AT MIDNIGHT. WILL HIGHLIGHT THE MODERATE TO
HEAVY RAIN FROM THIS CONVECTION WITH CONTINUED POSSIBILITY OF
PEA SIZE HAIL.
AS FOR TONIGHTS LOWS...LOOK FOR A 8-12 DEGREE RANGE OF MIN TEMPS DUE
TO THE EAST-WEST ORIENTATED FRONT BI-SECTING THE CWA.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...COLD FRONT IS EXPECTED TO BE DRAPED EAST-
WEST ACROSS THE CWA EARLY SATURDAY AND LIFT NORTH THROUGH THE
AFTERNOON. CONVECTION ASSOCIATED WITH 500 MB SHORTWAVE ENERGY
SHOULD BE MOVING OFF THE COAST IN THE MORNING. POPS WILL DECREASE
THROUGH THE DAY AS THE ATMOSPHERE DRIES OUT ABOVE 850 MB...THOUGH
IT WILL BE TOUGH TO RULE OUT AN ISOLATED TSTM DURING THE
AFTERNOON...ESPECIALLY ALONG THE SEA BREEZE BOUNDARY.
THE FRONT WILL REMAIN NORTH OF THE AREA THROUGH THE DAY SUNDAY.
WEST-SOUTHWEST LOW-LEVEL FLOW AND MID-UPPER RIDGING WILL SEE TEMPS
SOAR INTO THE MID 80S...EVEN UPPER 80S ACROSS THE SOUTHERN CWA. IT
APPEARS THAT AN ABSENCE OF MID-LEVEL MOISTURE ALONG WITH SUBSIDENCE
WILL PRECLUDE ANY SIGNIFICANT CHANCE OF CONVECTION. THE FRONT WILL
RETURN SOUTH AS A BACKDOOR COLD FRONT SUNDAY EVENING AND WILL
WARRANT AT LEAST SLIGHT CHANCE POPS ACROSS THE NORTHERN
CWA...PERHAPS FURTHER SOUTH DEPENDING ON ITS PROGRESS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...MODELS NOW MORE AGGRESSIVE WITH HIGH PRESSURE
PUSHING BACK DOOR COLD FRONT WELL TO OUR SOUTH ON MONDAY. GIVEN THE
STRENGTH OF THE UPPER TROUGH OFF OF CANADIAN MARITIMES THIS SEEMS
QUITE PLAUSIBLE. LOOKS LIKE IT WILL NOW WEAKEN TO THE POINT OF
WASHING OUT OFF TO OUR SOUTH AS THE DAY WEARS ON. WHILE THIS WILL
ACT TO KEEP HIGH TEMPERATURES COOL RELATIVE TO THE REST OF THE LONG
TERM IT DOES NOT ARGUE FOR MUCH IN THE WAY OF RAIN CHANCES
ASSOCIATED WITH THE BOUNDARY...NOR DOES THE BUILDING RIDGE ALOFT.
THIS RIDGE...CENTERED OVER FL/BAHAMAS...WILL REMAIN IN PLACE TUESDAY
AND WEDNESDAY WHILE THE SURFACE HIGH MOVES OFF THE EAST COAST.
WARMER AND MORE HUMID BOUNDARY LAYER AIR WILL THUS ADVECT UP AND
DOWN THE EAST COAST. THIS PATTERN WILL MORE OR LESS STAY AS-IS FOR
THE REMAINDER OF THE LONG TERM. EVENTUALLY SOME MESOSCALE FORCING
MAY SUPPORT ISOLATED CONVECTION ONCE HEAT AND MOISTURE BECOME
ADEQUATE BUT GIVEN THE UNCERTAINTY AND EXPECTED LOW COVERAGE THE
FORECAST WILL REMAIN DRY AT THIS TIME. TEMPS WILL BE ABOVE NORMAL
THROUGH THE PERIOD WITH THE EXCEPTION OF MONDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 23Z...A STATIONARY FRONT WAS ANALYZED FROM NORTH OF ILM TO
BETWEEN LBT/FLO. A SEA BREEZE WAS SEEN ON RADAR MOVING INLAND FROM
CRE/MYR. ANOTHER SURGE OF COOL AIR WAS MOVING EAST TO WEST AND HAS
MOVED THROUGH THE ILM TERMINAL. THUNDERSTORMS DURING THE AFTERNOON
HAVE LAID DOWN NUMEROUS OUTFLOW BOUNDARIES NEAR FLO.
SCATTERED THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP ALONG
AND SOUTH OF THE STATIONARY FRONT IN THE WARMEST AIR THIS EVENING.
BEST LIFT/THUNDERSTORM POTENTIAL WILL BE FROM FLO TO CRE/MYR. BASED
ON CURRENT RADAR AND SATELLITE TRENDS THUNDERSTORMS SHOULD REMAIN
ISOLATED. AFTER 03Z LIFT DECREASES AND THUNDERSTORMS SHOULD END. A
MODERATE UPPER LEVEL IMPULSE WILL MOVE INTO THE EASTERN CAROLINAS
AFTER LOCAL MIDNIGHT...WITH ANOTHER ROUND OF SHOWERS...WITH EMBEDDED
STORMS POSSIBLE. AS THIS IMPULSE PASSES THE FRONT WILL MOVE SLOWLY
SOUTH THROUGH THE REMAINING TERMINALS...WITH MVFR CEILINGS BECOMING
MORE LIKELY TOWARDS SUNRISE. BY MID MORNING SATURDAY EXPECT
IMPROVING CONDITIONS AS THE UPPER DISTURBANCE EXITS TO THE
NORTHEAST. A MVFR CEILING MAY LINGER...LIFTING TO VFR BY EARLY
SATURDAY AFTERNOON. ISOLATED THUNDERSTORMS WILL DEVELOP IN THE FRONT
NEAR MYR/CRE DURING THE AFTERNOON.
EXTENDED OUTLOOK...VFR SUNDAY. MVFR OR BRIEF IFR VSBYS IN MORNING
FOG POSSIBLE MONDAY THROUGH WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM FRIDAY...MSAS...SFC OBS/BUOYS...AND 88-D R/V BASE
DATA...ALL INDICATE THE NE-E PUSH BEHIND THE COLD FRONT HAS LIKELY
REACHED ITS FURTHEST INLAND AND SOUTHERN EXTENT...WITH LITTLE RIVER
INLET THE SOUTHERNMOST EXTENT. FOR NORTH OF THE FRONT...MODELS
INDICATE NE-E 10-15 KT. SOUTH OF THE FRONT...LOOK FOR A SOLID S-SW
WIND AROUND 15 KT DUE TO THE SLIGHTLY TIGHTER SFC PG. ENOUGH
CONVERGENCE ALONG THIS BOUNDARY AND DYNAMICS FROM A MID-LEVEL
S/W TROF LATE TONIGHT...TO AID WITH A SLOW INCREASING COVERAGE OF
CONVECTION ACROSS THE NORTHERN WATERS DURING THE REMAINDER OF THE
OVERNIGHT.
PER SWAN AND LATEST WAVEWATCH3 MODEL DATA...LOOK FOR SEAS TO SETTLE
IN THE 2 TO 4 FOOT RANGE DURING THE OVERNIGHT...WITH A DOMINANT 5 TO
7 SECONDS PERIOD.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...STATIONARY FRONT WILL BE DRAPED SOMEWHERE
NEAR THE NC-SC STATE LINE SATURDAY MORNING AND WILL MOVE TO THE
NORTH THROUGH THE DAY. WINDS NORTH OF THE FRONT WILL BE PRIMARILY
EAST...WITH A MORE SOUTHEASTERLY COMPONENT SOUTH OF THE BOUNDARY.
WINDS WILL SHIFT TO THE SOUTH-SOUTHWEST AS THE FRONT LIFTS NORTH
AND WILL REMAIN GENERALLY SOUTH-SOUTHWEST INTO SUNDAY EVENING. AT
THAT POINT THE FRONT WILL MOVE BACK TO THE SOUTH...AND THERE IS
SOME UNCERTAINTY ON HOW QUICKLY AND HOW FAR IT PROGRESSES. A SHIFT
TO THE NORTHEAST APPEARS LIKELY SUNDAY NIGHT FOR THE WATERS NORTH
OF LITTLE RIVER INLET...AND IS POSSIBLE FOR THE WATERS AS FAR
SOUTH AS THE SANTEE RIVER AS WELL.
AS FAR AS PRECIPITATION...EXPECT SCATTERED SHOWERS AND ISOLATED TSTMS
TO BE MOVING ACROSS THE WATERS EARLY SATURDAY IN ASSOCIATION WITH
A MID-LEVEL DISTURBANCE. THESE SHOULD EXIT THE WATERS BY LATE
MORNING...THEN ANY SIGNIFICANT CHANCE FOR CONVECTION APPEARS TO
HOLD OFF UNTIL SUNDAY EVENING AND WILL BE ASSOCIATED WITH THE
FRONTAL BOUNDARY DROPPING SOUTH.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...COLD FRONT PREVIOUSLY THOUGHT TO BE STALLED
ACROSS THE REGION EARLY MONDAY NOW MAY REMAIN WELL TO THE SOUTH.
THERE IS STILL SOME UNCERTAINTY ESPECIALLY IN LIGHT OF THIS SHIFT
BUT IT DOES SEEM PLAUSIBLE GIVEN THE POSITION AND STRENGTH OF
FEATURES ALOFT. EASTERLY/ONSHORE FLOW FOR THE EARLIER PARTS OF
MONDAY WILL BRING SOME HIGHER WAVE HEIGHTS ACROSS THE FORECAST
ZONES. THIS ONSHORE FLOW COMPONENT MAY NOW LAST A LITTLE LONGER THAN
PREVIOUSLY THOUGHT BY PERSISTING INTO MONDAY NIGHT AS THE HIGH OFF
THE COAST ONLY VERY SLOWLY PROGRESSES EAST. BY TUESDAY HOWEVER THE
ANTICIPATED VEER TO A MORE SOUTHERLY FLOW SPREADING NORTHWARD ACROSS
THE WATERS. THERE WILL NOT BE A SIGNIFICANT CHANGE IN WIND SPEED AS
THIS OCCURS BUT THE LESSENED ONSHORE COMPONENT SHOULD STILL
TRANSLATE TO A SLIGHT DIMINUTION OF WAVE HEIGHTS. SOUTHERLY
COMPONENT REMAINS THROUGH THE PERIOD BUT NOT THE TYPICAL BERMUDA
HIGH TYPE OF MODERATE SWRLY FLOW...THIS HIGH WILL BE CONSIDERABLY
DISPLACED EAST OF THAT. OVERALL WIND MAY BE A CATEGORY LOWER THAN
THOSE BORNE OF BERMUDA HIGH...AND THERE COULD BE SOME VARIABILITY
BETWEEN SOUTHERLY DIRECTIONS...I.E. SW TO S OR EVEN SE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CRM
NEAR TERM...DCH
SHORT TERM...CRM
LONG TERM...MBB
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
830 PM EDT FRI APR 27 2012
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER ACROSS THE AREA OVERNIGHT BEFORE
LIFTING NORTH ON SATURDAY. WARM SOUTHWEST FLOW WILL PREVAIL
THROUGH SUNDAY BEFORE THE FRONT DROPS BACK SOUTH AND CROSSES THE
AREA SUNDAY NIGHT. RELATIVELY COOL HIGH PRESSURE WILL BRIEFLY BUILD
IN BEHIND THE FRONT MONDAY...THEN MOVE OFFSHORE TUESDAY ALLOWING
THE RETURN OF A WARM SOUTHERLY FLOW THROUGH THE REMAINDER OF THE
WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 815 PM EDT FRIDAY...THE INLAND PROGRESSION OF THE SEA BREEZE
AND THE COOL SURGE FROM THE NE ASSOCIATED WITH THE BACKDOOR COLD
FRONT...HAS ADVECTED ENOUGH LOW LEVEL STABLE MARINE LAYER TO KEEP
CONVECTIVE ACTIVITY ACROSS THE ILM NC PORTION OF THE CWA TO A
MINIMUM WITH THE EXCEPTION OF THE EASTWARD CONVECTION WHEN IT PULSED
MOMENTARILY AS IT INTERACTED WITH THE SEA BREEZE ACROSS COLUMBUS
COUNTY...BEFORE FINALLY WEAKENING AS IT FURTHER TRACKED EASTWARD
INTO THE STABLE MARINE LAYER.
ADDITIONAL CONVECTION UPSTREAM IS EXPECTED TO RE-FIRE ALONG THE
STATIONARY FRONTAL BOUNDARY OVERNIGHT AND BASICALLY TRACK EAST ALONG
THIS BOUNDARY. BOTH LATEST RUC AND NAM MODELS INDICATE A MID LEVEL
S/W TROF TO TRACK ESE OVERNIGHT...REACHING THE ILM CWA DURING THE
PRE-DAWN SAT HOURS. ASSOCIATED DYNAMICS AND RESULTING UVVS TO
FURTHER AID CONVECTION TRACKING ALONG THE FRONT...AND AS A RESULT
WILL TREND WITH HIGHER POPS AS CONVECTION EXPECTED TO INCREASE IN
AREAL COVERAGE BY SUNRISE SATURDAY. AT THIS POINT...LOOKING AT BRIEF
PERIODS OF MODERATE TO HEAVY RAINFALL FROM THIS ACTIVITY AS THE
PRIMARY THREAT...WITH THE OCCASIONAL SMALL HAIL OR BRIEF 30 TO 45
MPH WIND GUSTS. LOOK FOR A 8-12 DEGREE RANGE OF MIN TEMPS DUE TO THE
EAST-WEST ORIENTATED COLD FRONT BI-SECTING THE ILM CWA.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...COLD FRONT IS EXPECTED TO BE DRAPED EAST-
WEST ACROSS THE CWA EARLY SATURDAY AND LIFT NORTH THROUGH THE
AFTERNOON. CONVECTION ASSOCIATED WITH 500 MB SHORTWAVE ENERGY
SHOULD BE MOVING OFF THE COAST IN THE MORNING. POPS WILL DECREASE
THROUGH THE DAY AS THE ATMOSPHERE DRIES OUT ABOVE 850 MB...THOUGH
IT WILL BE TOUGH TO RULE OUT AN ISOLATED TSTM DURING THE
AFTERNOON...ESPECIALLY ALONG THE SEA BREEZE BOUNDARY.
THE FRONT WILL REMAIN NORTH OF THE AREA THROUGH THE DAY SUNDAY.
WEST-SOUTHWEST LOW-LEVEL FLOW AND MID-UPPER RIDGING WILL SEE TEMPS
SOAR INTO THE MID 80S...EVEN UPPER 80S ACROSS THE SOUTHERN CWA. IT
APPEARS THAT AN ABSENCE OF MID-LEVEL MOISTURE ALONG WITH SUBSIDENCE
WILL PRECLUDE ANY SIGNIFICANT CHANCE OF CONVECTION. THE FRONT WILL
RETURN SOUTH AS A BACKDOOR COLD FRONT SUNDAY EVENING AND WILL
WARRANT AT LEAST SLIGHT CHANCE POPS ACROSS THE NORTHERN
CWA...PERHAPS FURTHER SOUTH DEPENDING ON ITS PROGRESS.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...MODELS NOW MORE AGGRESSIVE WITH HIGH PRESSURE
PUSHING BACK DOOR COLD FRONT WELL TO OUR SOUTH ON MONDAY. GIVEN THE
STRENGTH OF THE UPPER TROUGH OFF OF CANADIAN MARITIMES THIS SEEMS
QUITE PLAUSIBLE. LOOKS LIKE IT WILL NOW WEAKEN TO THE POINT OF
WASHING OUT OFF TO OUR SOUTH AS THE DAY WEARS ON. WHILE THIS WILL
ACT TO KEEP HIGH TEMPERATURES COOL RELATIVE TO THE REST OF THE LONG
TERM IT DOES NOT ARGUE FOR MUCH IN THE WAY OF RAIN CHANCES
ASSOCIATED WITH THE BOUNDARY...NOR DOES THE BUILDING RIDGE ALOFT.
THIS RIDGE...CENTERED OVER FL/BAHAMAS...WILL REMAIN IN PLACE TUESDAY
AND WEDNESDAY WHILE THE SURFACE HIGH MOVES OFF THE EAST COAST.
WARMER AND MORE HUMID BOUNDARY LAYER AIR WILL THUS ADVECT UP AND
DOWN THE EAST COAST. THIS PATTERN WILL MORE OR LESS STAY AS-IS FOR
THE REMAINDER OF THE LONG TERM. EVENTUALLY SOME MESOSCALE FORCING
MAY SUPPORT ISOLATED CONVECTION ONCE HEAT AND MOISTURE BECOME
ADEQUATE BUT GIVEN THE UNCERTAINTY AND EXPECTED LOW COVERAGE THE
FORECAST WILL REMAIN DRY AT THIS TIME. TEMPS WILL BE ABOVE NORMAL
THROUGH THE PERIOD WITH THE EXCEPTION OF MONDAY.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 23Z...A STATIONARY FRONT WAS ANALYZED FROM NORTH OF ILM TO
BETWEEN LBT/FLO. A SEA BREEZE WAS SEEN ON RADAR MOVING INLAND FROM
CRE/MYR. ANOTHER SURGE OF COOL AIR WAS MOVING EAST TO WEST AND HAS
MOVED THROUGH THE ILM TERMINAL. THUNDERSTORMS DURING THE AFTERNOON
HAVE LAID DOWN NUMEROUS OUTFLOW BOUNDARIES NEAR FLO.
SCATTERED THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP ALONG
AND SOUTH OF THE STATIONARY FRONT IN THE WARMEST AIR THIS EVENING.
BEST LIFT/THUNDERSTORM POTENTIAL WILL BE FROM FLO TO CRE/MYR. BASED
ON CURRENT RADAR AND SATELLITE TRENDS THUNDERSTORMS SHOULD REMAIN
ISOLATED. AFTER 03Z LIFT DECREASES AND THUNDERSTORMS SHOULD END. A
MODERATE UPPER LEVEL IMPULSE WILL MOVE INTO THE EASTERN CAROLINAS
AFTER LOCAL MIDNIGHT...WITH ANOTHER ROUND OF SHOWERS...WITH EMBEDDED
STORMS POSSIBLE. AS THIS IMPULSE PASSES THE FRONT WILL MOVE SLOWLY
SOUTH THROUGH THE REMAINING TERMINALS...WITH MVFR CEILINGS BECOMING
MORE LIKELY TOWARDS SUNRISE. BY MID MORNING SATURDAY EXPECT
IMPROVING CONDITIONS AS THE UPPER DISTURBANCE EXITS TO THE
NORTHEAST. A MVFR CEILING MAY LINGER...LIFTING TO VFR BY EARLY
SATURDAY AFTERNOON. ISOLATED THUNDERSTORMS WILL DEVELOP IN THE FRONT
NEAR MYR/CRE DURING THE AFTERNOON.
EXTENDED OUTLOOK...VFR SUNDAY. MVFR OR BRIEF IFR VSBYS IN MORNING
FOG POSSIBLE MONDAY THROUGH WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 745 PM FRIDAY...THE USAGE OF MSAS...SFC OBS/BUOYS...AND 88-D
R/V BASE DATA...ALL INDICATED THE NE-E PUSH BEHIND THE COLD FRONT
HAS REACHED THE WATERS FROM CAPE FEAR NORTHWARD. MODELS INDICATE THE
FRONT TO STALL IN THE VICINITY OF LITTLE RIVER INLET OVERNIGHT.
NORTH OF THE FRONT MODELS INDICATE NE-E 10-15 KT. SOUTH OF THE
FRONT...LOOK FOR A SOLID S-SW WIND AROUND 15 KT DUE TO THE SLIGHTLY
TIGHTER SFC PG. ENOUGH CONVERGENCE ALONG THIS BOUNDARY AND DYNAMICS
FROM AN UPPER LEVEL S/W TROF LATE TONIGHT...TO AID WITH A SLOW
INCREASING COVERAGE OF CONVECTION DURING THE PRE-DAWN HRS OF
SATURDAY.
PER SWAN AND LATEST WAVEWATCH3 MODEL DATA...LOOK FOR SEAS TO SETTLE
IN THE 2 TO 4 FOOT RANGE DURING THE OVERNIGHT...WITH A DOMINANT 5 TO
7 SECONDS PERIOD.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...STATIONARY FRONT WILL BE DRAPED SOMEWHERE
NEAR THE NC-SC STATE LINE SATURDAY MORNING AND WILL MOVE TO THE
NORTH THROUGH THE DAY. WINDS NORTH OF THE FRONT WILL BE PRIMARILY
EAST...WITH A MORE SOUTHEASTERLY COMPONENT SOUTH OF THE BOUNDARY.
WINDS WILL SHIFT TO THE SOUTH-SOUTHWEST AS THE FRONT LIFTS NORTH
AND WILL REMAIN GENERALLY SOUTH-SOUTHWEST INTO SUNDAY EVENING. AT
THAT POINT THE FRONT WILL MOVE BACK TO THE SOUTH...AND THERE IS
SOME UNCERTAINTY ON HOW QUICKLY AND HOW FAR IT PROGRESSES. A SHIFT
TO THE NORTHEAST APPEARS LIKELY SUNDAY NIGHT FOR THE WATERS NORTH
OF LITTLE RIVER INLET...AND IS POSSIBLE FOR THE WATERS AS FAR
SOUTH AS THE SANTEE RIVER AS WELL.
AS FAR AS PRECIPITATION...EXPECT SCATTERED SHOWERS AND ISOLATED TSTMS
TO BE MOVING ACROSS THE WATERS EARLY SATURDAY IN ASSOCIATION WITH
A MID-LEVEL DISTURBANCE. THESE SHOULD EXIT THE WATERS BY LATE
MORNING...THEN ANY SIGNIFICANT CHANCE FOR CONVECTION APPEARS TO
HOLD OFF UNTIL SUNDAY EVENING AND WILL BE ASSOCIATED WITH THE
FRONTAL BOUNDARY DROPPING SOUTH.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...COLD FRONT PREVIOUSLY THOUGHT TO BE STALLED
ACROSS THE REGION EARLY MONDAY NOW MAY REMAIN WELL TO THE SOUTH.
THERE IS STILL SOME UNCERTAINTY ESPECIALLY IN LIGHT OF THIS SHIFT
BUT IT DOES SEEM PLAUSIBLE GIVEN THE POSITION AND STRENGTH OF
FEATURES ALOFT. EASTERLY/ONSHORE FLOW FOR THE EARLIER PARTS OF
MONDAY WILL BRING SOME HIGHER WAVE HEIGHTS ACROSS THE FORECAST
ZONES. THIS ONSHORE FLOW COMPONENT MAY NOW LAST A LITTLE LONGER THAN
PREVIOUSLY THOUGHT BY PERSISTING INTO MONDAY NIGHT AS THE HIGH OFF
THE COAST ONLY VERY SLOWLY PROGRESSES EAST. BY TUESDAY HOWEVER THE
ANTICIPATED VEER TO A MORE SOUTHERLY FLOW SPREADING NORTHWARD ACROSS
THE WATERS. THERE WILL NOT BE A SIGNIFICANT CHANGE IN WIND SPEED AS
THIS OCCURS BUT THE LESSENED ONSHORE COMPONENT SHOULD STILL
TRANSLATE TO A SLIGHT DIMINUTION OF WAVE HEIGHTS. SOUTHERLY
COMPONENT REMAINS THROUGH THE PERIOD BUT NOT THE TYPICAL BERMUDA
HIGH TYPE OF MODERATE SWRLY FLOW...THIS HIGH WILL BE CONSIDERABLY
DISPLACED EAST OF THAT. OVERALL WIND MAY BE A CATEGORY LOWER THAN
THOSE BORNE OF BERMUDA HIGH...AND THERE COULD BE SOME VARIABILITY
BETWEEN SOUTHERLY DIRECTIONS...I.E. SW TO S OR EVEN SE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CRM
NEAR TERM...DCH
SHORT TERM...CRM
LONG TERM...MBB
AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
751 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 /00Z FRIDAY THROUGH TUESDAY/...
AS OF 745 PM FRIDAY...
VFR CONDITIONS ARE EXPECTED TO PREVAIL FOR THE REMAINDER OF THE
EVENING HOURS ACROSS ALL OF CENTRAL NC. THEN...AS THE LOW LEVEL FLOW
GRADUALLY BECOMES NORTHEASTERLY THROUGH EARLY SATURDAY...COOL AND
MOIST AIR WILL MOVE INTO THE REGION AND RESULT IN THE DEVELOPMENT OF
MVFR CIGS...GENERALLY BETWEEN 09-12Z. THESE MVFR CIGS ARE EXPECTED
TO PERSIST THROUGH MUCH OF THE DAY ON SATURDAY...BEFORE LIFTING TO
VFR LATE SATURDAY AS THE WINDS BECOME MORE SOUTHEASTERLY WITH THE
PASSAGE OF A WARM FRONT.
OUTLOOK...THE AFOREMENTIONED FRONT IS THEN EXPECTED TO LINGER NEAR
THE REGION THROUGH EARLY NEXT WEEK. ALTHOUGH MOSTLY VFR CONDITIONS
ARE EXPECTED...PERIODS OF SUB-VFR CONDITIONS WILL BE LIKELY AND
HINGE ON THE LOCATION OF THE FRONT...THEREFORE CONFIDENCE REMAINS
LOW WITH RESPECT TO THE TIMING OF ANY ADVERSE AVIATION CONDITIONS.
ALSO...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...KRR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
321 PM EDT THU APR 26 2012
.SYNOPSIS...
A COLD FRONT WILL DIP INTO THE COASTAL CAROLINAS LATE TONIGHT...
STALLING FRIDAY...THEN LIFTING NORTH SATURDAY. THE FRONT WILL
RETURN SOUTH LATE SATURDAY NIGHT AND FINALLY GET PUSHED OUT OF THE
AREA AS CANADIAN HIGH PRESSURE SURGES SOUTH ALONG THE ATLANTIC
COAST INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM THURSDAY...A STRONG UPPER DISTURBANCE IS PUSHING ACROSS
VIRGINIA AND NORTHERN NORTH CAROLINA THIS AFTERNOON. ALONG THE FRONT
EDGE OF THIS DISTURBANCE THIS MORNING A SQUALL LINE CAME ROARING OUT
OF THE MOUNTAINS BUT DIED OUT AS IT CROSSED INTERSTATE 77. THE TAIL
END OF THIS UPPER DISTURBANCE HAS DEVELOPED A NEW CLUSTER OF
CONVECTION THIS AFTERNOON IN THE SC SANDHILLS BACK TO JUST SOUTH OF
CHARLOTTE. THESE NEW STORMS APPEARS TO BE LARGELY ELEVATED IN NATURE
ALTHOUGH THEY RISK BECOMING SURFACE-BASED AS THEY MOVE INTO A MORE
DEEPLY-MIXED REGION IN THE SC/NC COASTAL PLAIN WHERE DRY-ADIABATIC
LAPSE RATES EXIST FROM THE SURFACE UP THROUGH AT LEAST 5500 FT.
RISKS ASSOCIATED WITH THESE STORMS MAY TRANSITION FROM LIGHTNING AND
HAIL TO DAMAGING WINDS. FOR THE NEXT SEVERAL HOURS WE`RE FORECASTING
THIS BATCH OF STORMS TO AFFECT AREAS FROM BENNETTSVILLE AND DILLON
ACROSS SOUTHERN ROBESON COUNTY...PERHAPS MAKING IT INTO THE
WHITEVILLE AREA TOWARD 6 PM. POPS HAVE BEEN INCREASED TO 50-80
PERCENT IN THIS REGION FROM 3-6 PM.
A SECOND UPPER DISTURBANCE IN TENNESSEE AND KENTUCKY IS EXPECTED TO
FOLLOW THIS EVENING IN THE FOOTSTEPS OF OUR FIRST DISTURBANCE.
CLUSTERS OF THUNDERSTORMS ACROSS E TN INTO THE NC MOUNTAINS WILL
PUSH EAST AND INTO THE CENTRAL AND EASTERN CAROLINAS BY SUNSET. THE
LAST FEW HRRR RUNS SHOW THIS ACTIVITY MOVING EAST ACROSS THE
NORTHERN HALF OF OUR FORECAST AREA BETWEEN 7 PM AND MIDNIGHT. POPS
IN THE 30-50 PERCENT RANGE ARE FORECAST ALONG AND NORTH OF A LINE
FROM DARLINGTON...DILLON...WHITEVILLE AND BURGAW DURING THAT TIME
FRAME.
AFTER MIDNIGHT CONVECTION SHOULD PUSH EAST OF THE AREA AND BREEZY
WINDS SHOULD BEGIN TO DIE DOWN AS THE PRESSURE GRADIENT RELAXES AND
THE BOUNDARY LAYER BECOMES MORE STABLE. BY DAYBREAK A SYNOPTIC COLD
FRONT WILL BE KNOCKING ON THE DOOR FROM THE NORTH. MODELS ARE NOT IN
GOOD AGREEMENT WITH PRECISELY HOW FAR SOUTH THE BOUNDARY MOVES. THE
GFS IS THE SOUTHERNMOST SOLUTION BUT DOESN`T SEEM TOO UNREASONABLE
GIVEN ALL THE CONVECTION EXPECTED ACROSS NORTHERN AND CENTRAL NC
TONIGHT WHICH COULD HELP PUSH THE BOUNDARY SOUTH. LOWS ARE EXPECTED
TO RUN 5-10 DEGREES ABOVE NORMAL...RANGING FROM 60 INLAND TO THE MID
60S ON THE SC COAST.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...COLD FRONT WILL BE MOVING DOWN FROM THE
NORTH THROUGH OUR AREA ON FRIDAY MORNING BEFORE STALLING OUT CLOSE
TO THE NC/SC BORDER BY AFTERNOON. THE SHORTWAVE DRIVING THIS FRONT
SHIFTS OFF SHORE BY MID MORNING LEAVING MORE IN THE WAY OF
SUBSIDENCE IN ITS WAKE. THIS FRONT WILL REMAIN BISECTING OUR CWA
THROUGH FRIDAY AND WILL REMAIN THE FOCAL POINT FOR PCP. IT LOOKS
LIKE THE BEST CHC OF SHWRS WILL BE IN THE MOISTURE RICH AIR TO THE
SOUTH OF THE FRONT FROM THE NC/SC BORDER TO CAPE FEAR AND SOUTH
OVER SC EARLIER AND MOVING NORTH LATER IN THE DAY. WITH
SUBSIDENCE PRESENT EARLIER IN THE DAY...THINK WE WILL SQUEEZE OUT
A DECENT MORNING OVER MOST AREAS BUT EXPECT CLOUDS AND SHWRS/TSTMS
IN VICINITY OF FRONT AND BETTER CHC LATER IN DAY INTO OVERNIGHT
HOURS AS NEXT SHORTWAVE MOVES THROUGH.
MID TO UPPER RIDGE ALONG THE MISSISSIPPI VALLEY ON FRI WILL MOVE
EAST. FLOW ALOFT BECOMES MORE PARALLEL KEEPING FRONT IN THE
VICINITY THROUGH FRI BUT IT WILL MOVE BACK NORTH ON SATURDAY AS A
GENERAL W-SW FLOW DEVELOPS ALOFT AS SHORTWAVE MOVES THROUGH.
LATEST NAM AND GFS WERE A BIT SLOWER TO MOVE THIS BOUNDARY BACK
NORTH WHICH MAY KEEP CLOUDS AND POSSIBLE PCP IN FORECAST SAT
MORNING. THE SHALLOW COOL AIR WILL REMAIN INLAND AND NORTH WHILE
WARMER AIR PUSHES NORTH ALONG THE COAST INITIALLY. THIS
TROUGH/FRONT OVER AREA WILL MOVE NORTH SAT AFTERNOON BUT WILL GET
HELD UP ONCE AGAIN JUST NORTH OF OUR AREA BY SUNDAY MORNING.
OVERALL EXPECT A CLOUDIER AND WETTER SAT THAN IT LOOKED A FEW DAYS
BACK.
TEMPS WILL BE ANOTHER CHALLENGE. EXPECT HIGHS UP TO 10 DEGREES
COOLER TO THE NORTH VS SOUTH OF FRONT. FLORENCE AREA TO COASTAL SC
SHOULD BE IN THE MID 80S WHILE LUMBERTON AND THE NORTHERN TIER OF
CWA WILL SEE READINGS IN THE MID 70S. OVERNIGHT LOWS WILL REMAIN
WARMER WITH CLOUDS AND PCP PRESENT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...BACK DOOR COLD FRONT CROSSES SOUTH THROUGH
THE CWA SUNDAY. VERY LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH
THIS FEATURE HAS PROMPTED EVEN FURTHER REDUCTION FROM INHERITED
POP...WITH SCHC NOW CONFINED TO ONLY THE NORTHERN HALF OF THE AREA.
IF THIS DRYING PATTERN CONTINUES...WILL LIKELY NEED TO REMOVE ANY
MENTION OF SHOWERS ALTOGETHER WITH LATER UPDATES. AS THIS FRONT
MOVES SOUTH...IT WILL RESTRICT MAX TEMPS TO ONLY THE MID 70S ACROSS
THE NORTH...WITH LOWER 80S LIKELY IN THE FAR SOUTHWEST WHERE FROPA
OCCURS LATER.
VERY SIGNIFICANT MODEL DIFFERENCES EXIST NOW FOR MON/TUE WHICH
CREATE LOWERED CONFIDENCE FOR THIS PART OF THE FORECAST. GFS STILL
SHOWS A STRONG WEDGE OF HIGH PRESSURE HOLDING ACROSS THE CAROLINAS
MONDAY INTO TUESDAY...WHILE CMC/ECMWF HAVE BACKED OFF ON THIS
FEATURE. ALTHOUGH HPC CONTINUES TO FAVOR THE ECMWF...THE RECENT
CONSISTENCY OF THE GFS CANNOT BE IGNORED EVEN IF IT IS THE OUTLIER
NOW. ADMITTEDLY...IT IS CLIMATOLOGICALLY QUITE DIFFICULT TO GET A
STRONG WEDGE THIS TIME OF YEAR SO THE ECMWF SOLUTION MAY BE MORE
REALISTIC...BUT HESITATE TO MAKE ANY SIGNIFICANT CHANGES TO THIS
PORTION OF THE FORECAST DUE TO UNCERTAINTY. SO WILL JUST ADJUST
TEMPS UPWARD A BIT...BUT OTHERWISE LEAVE PRETTY MUCH UNCHANGED FOR
NOW.
BY LATE TUESDAY ANY REMNANT WEDGING...IF ANY...ERODES AS HIGH
PRESSURE DRIFTS OFFSHORE AND WARM SOUTHERLY RETURN FLOW ENVELOPS THE
AREA. THIS WILL BRING BACK WEATHER MORE TYPICAL OF EARLY MAY...WITH
TEMPS RISING TO ABOVE CLIMO WED/THU.
&&
.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 18Z...MCS IS DYING WITH MOST OF THE MOISTURE REMAINING NORTH
OF THE REGION. EXPECT SCATTERED CONVECTION TO REFIRE THIS AFTERNOON.
COVERAGE AND TIMING ARE STILL AN ISSUE...BUT WITH THE STEEP MID
LEVEL LAPSE RATES THERE WILL LIKELY BE SOME STRONG STORMS SOMEWHERE
IN THE EASTERN CAROLINAS. WE THINK THE BEST CHANCE WILL BE ACROSS NC
WHERE THE HIGHEST PRECIPITABLE WATER VALUES ARE. STRONG SOUTHWEST
SURFACE WINDS WILL CONTINUE THROUGH THE AFTERNOON HOURS...GUSTS TO
30 KTS LIKELY. TONIGHT...A SECONDARY ROUND OF CONVECTION IS POSSIBLE
WITH A SECOND UPPER DISTURBANCE. SURFACE WINDS WILL DIMINISH BUT
WILL REMAIN ABOVE 8 KTS MOST OF THE NIGHT. FRIDAY...EXPECT VFR WITH
MORE OF A NORTHWESTERLY FLOW AS A POORLY DEFINED FRONT SAGS SOUTH.
LOOK FOR CONVECTION TO REFIRE FRIDAY AFTERNOON.
EXTENDED OUTLOOK...SCATTERED SHOWERS AND STORMS POSSIBLE FRIDAY
AFTERNOON THROUGH THE EVENING HOURS. ISOLATED STORMS SATURDAY. VFR
SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM THURSDAY...LOW PRESSURE IS DEEPENING ACROSS SOUTHEAST
VIRGINIA THIS AFTERNOON AND SHOULD PUSH OUT INTO THE WESTERN
ATLANTIC THIS EVENING. THIS LOW HAS PRODUCED A TIGHTENED PRESSURE
GRADIENT BETWEEN ITSELF AND HIGH PRESSURE RIDGING WEST ACROSS THE
FLORIDA PENINSULA. STRONG SOUTHWEST WINDS SHOULD GRADUALLY DIMINISH
OVERNIGHT AS THE GRADIENT TIGHTENS...AND AS A COLD FRONT SLIDES
SOUTH TOWARD THE REGION. THIS FRONT MAY BEGIN TO MOVE INTO THE CAPE
FEAR REGION AROUND DAYBREAK FRIDAY...OTHERWISE EXPECT LARGELY
SOUTHWEST WINDS TO PREVAIL OVERNIGHT.
THUNDERSTORMS DEVELOPING IN THE CENTRAL AND WESTERN CAROLINAS WILL
MOVE EAST AND MAY BEGIN TO AFFECT THE COASTAL WATERS MAINLY NORTH OF
MYRTLE BEACH THIS EVENING. GUSTY WINDS AND LIGHTNING THE PRIMARY
EXPECTED THREATS.
WITH STRONG WINDS OVER THE PAST 12 HOURS HAVE DEVELOPED QUITE A
ROUGH SEA STATE. SEA HEIGHTS ARE BEING MEASURED AS HIGH AS 8-9 FEET
OUT AT THE FRYING PAN SHOALS BUOY...WITH 5-6 FT CLOSER TO SHORE AT
THE CORMP BUOYS. SEAS WILL GRADUALLY DIMINISH OVERNIGHT AS WINDS DIE
AWAY BUT IT WILL TAKE TIME.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...COLD FRONT WILL DROP SOUTH AND STALL NEAR
CAPE FEAR REMAINING DRAPED ACROSS AREA ON FRIDAY INTO SATURDAY.
THIS WILL CREATE LIGHTER AND MORE VARIABLE WINDS OVER THE LOCAL
WATERS. THERE WILL BE AN OVERALL DECREASE IN WINDS AND SEAS AS
GRADIENT WEAKENS OVER AREA. SEAS WILL START OUT NEAR SCA BUT WILL
DIMINISH QUICKLY THROUGH AFTERNOON DOWN TO 3 FT OR LESS BY LATE
AFTERNOON. WINDS WILL BE N-NE VEERING AROUND TO THE E-NE NORTH OF
THE FRONT AND WILL BE SOUTHERLY TO THE SOUTH OF BOUNDARY. BY SAT
AFTERNOON FRONT WILL MOVE BACK NORTH AGAIN AND A SLIGHT INCREASE
IN S WINDS WILL DRIVE SEAS BACK UP A BIT REACHING 3 TO 4 FT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...BACK DOOR COLD FRONT CROSSES THE WATERS
SUNDAY SO WINDS WILL BE LIGHT AND VARIABLE DURING FRONTAL
PASSAGE...BECOMING NE AND INCREASING TO AROUND 15 KTS LATE SUNDAY
BEHIND THE FRONT. SEAS WILL BE PREDOMINANTLY 2-4 FT THROUGH MOST OF
SUNDAY...BUILDING TO 3-5 FT LATE DUE TO THE INCREASING WINDS.
MODERATE NE WINDS PERSIST MUCH OF MONDAY BEFORE EASING AND VEERING
GRADUALLY TO THE SE TUESDAY AS HIGH PRESSURE DRIFTS OFFSHORE. SEAS
STAY ELEVATED THROUGH THE FIRST HALF OF MONDAY...3-5 FT EXCEPT IN
THE FAVORED SHADOW REGIONS SW OF FRYING PAN SHOALS. CAUTIONARY
HEADLINES APPEAR LIKELY LATE SUNDAY INTO MONDAY...BUT CONDITIONS MAY
REMAIN JUST BELOW SCA THRESHOLDS. SEAS THEN FALL BACK TO 2-4 FT LATE
MONDAY AND TUESDAY WITH AN INCREASING SE SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...TRA/DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1224 PM EDT THU APR 26 2012
.SYNOPSIS...
...STRONG AND GUSTY SOUTHWEST WINDS INTO THIS EVENING...
STRONG LOW PRESSURE WILL PASS TO OUR NORTH TODAY...ACCOMPANIED BY
STRONG WINDS. SCATTERED THUNDERSTORMS THIS AFTERNOON INTO THIS
EVENING COULD BRING EVEN STRONGER WIND GUSTS...ESPECIALLY ACROSS
NORTH CAROLINA. A COLD FRONT WILL DIP INTO THE COASTAL CAROLINAS
LATE TONIGHT... STALLING FRIDAY...THEN LIFTING NORTH SATURDAY. THE
FRONT WILL RETURN SOUTH LATE SATURDAY NIGHT AS CANADIAN HIGH
PRESSURE SURGES SOUTH ALONG THE ATLANTIC COAST INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM THURSDAY...MCS/SQUALL LINE TO OUR WEST IS FALLING
APART AS EARLIER FORECAST. OBSERVATIONS WITHIN THE REMNANT RAIN AREA
SHOW CLOUD CEILINGS AT OR ABOVE 8500 FT AGL. IF ANY OF THE PRECIP
REACHES THE GROUND IN OUR SOUTH CAROLINA PEE DEE COUNTIES ONLY A
COUPLE HUNDREDTHS OF AN INCH ARE POSSIBLE GIVEN THE DEEP DRY
SUB-CLOUD LAYER. NEW CONVECTION REMAINS POSSIBLE AFTER 18-19Z AS THE
SURFACE CONTINUES TO WARM AND DESTABILIZE. NO SIGNIFICANT CHANGES ARE
NEEDED FOR THE FORECAST EARLY THIS AFTERNOON. PREVIOUS DISCUSSION
FROM 1030 AM FOLLOWS...
SURFACE LOW PRESSURE IN OHIO WILL MOVE INTO NEW ENGLAND TONIGHT...AS
A SECONDARY LOW DEVELOPS ACROSS VIRGINIA AND MOVES OFFSHORE THIS
EVENING. BOTH OF THESE LOWS ARE THE RESULT OF UPPER DISTURBANCES: A
STRONG ONE OVER LAKE SUPERIOR AND A WEAKER ONE MOVING INTO THE
VIRGINIA/NC MOUNTAINS THIS MORNING.
AN IMPRESSIVE SQUALL LINE ACROSS THE SOUTHERN APPALACHIANS THIS
MORNING HAS PUSHED EAST OF THE MOUNTAINS AND TO INTERSTATE 77 AT THE
TIME OF THIS WRITING. EVEN THE HOURLY HRRR RUNS HAVE FAILED TO KEEP
UP WITH THE RAPID SOUTH AND EASTWARD MOTION OF THIS LINE. TYPICALLY
WE EXPECT ORGANIZED CONVECTIVE SYSTEMS TO WEAKEN DURING THE LATE
MORNING DUE TO DETERIORATION OF THE LOW-LEVEL JET AS SUNSHINE
STEEPENS LOW-LEVEL LAPSE RATES AND THE MOMENTUM OF THE JET BECOMES
DISTRIBUTED OVER A DEEPER LAYER DOWN TO THE SURFACE. THE HRRR SHOWS
WEAKENING OF THE LINE BETWEEN NOW AND 16Z/NOON EDT...BUT STILL
MAINTAINS AT LEAST SOME CONVECTIVE ACTIVITY ARRIVING IN THE
BENNETTSVILLE AND LUMBERTON AREAS BY 17-18Z/1-2 PM EDT. THE
ATMOSPHERE WILL BECOME MODERATELY UNSTABLE ACROSS THIS REGION WITH
SURFACE-BASED CAPE RISING TO 1500 J/KG...-5 LIFTED INDICES...AND
LITTLE CAPPING. FORECAST WIND PROFILES ALSO SHOW SUFFICIENT VERTICAL
SHEAR FOR ORGANIZED STORMS (0-6 KM BULK SHEAR 30-40 KT). ANY
ACTIVITY SHOULD MOVE EAST ACROSS INTERIOR SOUTHEAST NORTH CAROLINA
DURING THE AFTERNOON...WITH DAMAGING WIND GUSTS THE PRIMARY THREAT.
FARTHER SOUTH INTO SOUTH CAROLINA...A CONVECTIVE CAP BETWEEN 800-700
MB (6500-10000 FT AGL) WILL ACT TO INHIBIT STORM DEVELOPMENT AND
THERE IS A MUCH LOWER CHANCE OF STORMS HERE DURING THE DAYLIGHT
HOURS. EVEN THE SEABREEZE MAY NOT EXTEND HIGH ENOUGH INTO THE
ATMOSPHERE TO OVERCOME THIS CAP AND WE ARE MAINTAINING A DRY
FORECAST INTO LATE AFTERNOON AWAY FROM THE NORTH CAROLINA STATE LINE.
VERY BREEZY CONDITIONS ARE EXPECTED TODAY DUE TO A TIGHT PRESSURE
GRADIENT ALONG THE SOUTH SIDE OF THE DEVELOPING SURFACE LOW IN
VIRGINIA. RADAR WIND PROFILES SHOW 50 KT WINDS AS LOW AS 4000
FT AGL...AND 30-40 KT WINDS AT 1000-2000 FT AGL. STRONG INSOLATION
SHOULD STEEPEN LAPSE RATES SUFFICIENTLY TO BRING GUSTS TO 30 KT (35
MPH) TO THE SURFACE RATHER EASILY TODAY EVEN OUTSIDE OF
THUNDERSTORMS.
TONIGHT MODELS SHOW A SECOND UPPER DISTURBANCE DIVING SOUTHEAST
ACROSS THE AREA. EARLIER STORMS ACROSS CENTRAL NORTH CAROLINA SHOULD
HAVE SHARPENED UP A FRONTAL BOUNDARY WHICH MAY ACT TO PROVIDE A
LITTLE STRONGER FOCUS FOR STORMS AFTER DARK.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT IN THE AREA FRI WITH THE
LATEST GUIDANCE NOW STALLING THE FRONT ACROSS SOUTHERN PORTIONS OF
THE FORECAST AREA AT THE START OF THE PERIOD. FRONT SLOWLY LIFTS
NORTH LATER FRI INTO FRI NIGHT AS SURFACE WAVE AND SHORTWAVE ALOFT
MOVE EAST ACROSS THE AREA. FORECAST SOUNDINGS AND CROSS SECTIONS
SHOW A NARROW BAND OF DEEP MOISTURE LIFTING INTO THE AREA LATE FRI
NIGHT. WHILE THERE IS NO SURFACE BASED INSTABILITY TO SPEAK OF THERE
IS SOME ISENTROPIC LIFT ALONG THE FRONT COINCIDENT WITH DIVERGENCE
ALOFT. IT NOW APPEARS THE BEST PRECIP CHANCES WILL BE FRI NIGHT AS
THE FRONT LIFTS BACK NORTH AND WEAK SURFACE WAVE TRAVELS EAST. LACK
OF STRONG FORCING AND NOCTURNAL TIMING WILL LIKELY RESULT IN LIGHT
PATCHES OF RAIN OVERNIGHT...LOW CHANCE SHOULD COVER MOST OF THE AREA
WITH ONLY A COUPLE HUNDREDTHS OF QPF.
FORECAST FOR SAT REMAINS UP IN THE AIR. 00Z GFS PUSHES THE SURFACE
FRONT NORTH OF THE REGION AS WEAK 5H RIDGE BUILDS NORTH AND LOW
PRESSURE MOVES THROUGH THE KY VALLEY. HOWEVER THE NAM/CANADIAN/AND
12Z ECMWF KEEP THE FRONT STALLED IN THE AREA WITH SHOWERS AND
THUNDERSTORMS DEVELOPING IN THE AFTERNOON. GIVEN THE CONSENSUS
BETWEEN THE 00Z NAM/CANADIAN...12Z ECMWF AND HPC WILL FAVOR THE
WETTER COOLER SOLUTION FOR SAT. GOING TO INTRODUCE POP FOR SAT/SAT
NIGHT...THOUGH ONLY SLIGHT CHANCE FOR NOW AND KNOCK BACK TEMPS A
DEGREE OR TWO. HOWEVER...IF THE GFS SOLUTION IS THE CORRECT ONE
TEMPERATURES COULD BE 5 DEGREES WARMER SAT AFTERNOON WITH NO THREAT
OF PRECIP. FRONT EVENTUALLY PUSHES NORTH OF THE AREA LATE SAT OR SAT
NIGHT WITH WEAK WARM ADVECTION KEEPING TEMPERATURES ABOVE CLIMO
OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT WILL DROP SOUTH ACROSS THE
AREA SUN...FOLLOWED BY STRONG CANADIAN HIGH RIDGING DOWN THE COAST.
PASSAGE OF THE FRONT IS LOOKING LESS AND LESS LIKE A PRECIP EVENT.
DEEP WEST TO NORTHWEST FLOW AHEAD OF THE FRONT HELPS DRY THE
COLUMN...AIDED BY WEAK 5H RIDGE BUILDING OVER THE SOUTHEAST.
NORTHEAST FLOW CONTINUES MON INTO TUE WITH SURFACE HIGH WEDGING DOWN
THE EASTERN SEABOARD. SURFACE RIDGE AXIS STARTS TO SHIFT OFFSHORE
LATE TUE BUT IS INITIALLY SLOW TO MOVE SOUTHEAST OF THE AREA. RETURN
FLOW STARTS TO DEVELOP ON WED AS THE CENTER OF THE HIGH PUSHES
FARTHER OFF THE EAST COAST. DO SEE A HINT OF A WEAK COASTAL TROUGH
DEVELOP TUE NIGHT INTO WED BUT VERY DRY AIR IN PLACE MINIMIZES THE
THREAT OF PRECIP. PERIOD REMAINS DRY WITH SURFACE AND UPPER RIDGING
IN PLACE. TEMPERATURES SUN AHEAD OF THE FRONT SHOULD BE NEAR
CLIMO...BUT THEN MON AND TUE END UP BELOW CLIMO IN COOL NORTHEAST
FLOW. MON WILL LIKELY BE THE COOLEST DAY WITH SOME WARMING TUE AS
THE AIR MASS MODIFIES. RETURN FLOW AT THE END OF THE PERIOD WILL
RETURN TEMPS BACK TO CLIMO.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...MCS IS DYING WITH MOST OF THE MOISTURE REMAINING NORTH
OF THE REGION. EXPECT SCATTERED CONVECTION TO REFIRE THIS AFTERNOON.
COVERAGE AND TIMING ARE STILL AN ISSUE...BUT WITH THE STEEP MID
LEVEL LAPSE RATES THERE WILL LIKELY BE SOME STRONG STORMS SOMEWHERE
IN THE EASTERN CAROLINAS. WE THINK THE BEST CHANCE WILL BE ACROSS NC
WHERE THE HIGHEST PRECIPITABLE WATER VALUES ARE. STRONG SOUTHWEST
SURFACE WINDS WILL CONTINUE THROUGH THE AFTERNOON HOURS...GUSTS TO
30 KTS LIKELY. TONIGHT...A SECONDARY ROUND OF CONVECTION IS POSSIBLE
WITH A SECOND UPPER DISTURBANCE. SURFACE WINDS WILL DIMINISH BUT
WILL REMAIN ABOVE 8 KTS MOST OF THE NIGHT. FRIDAY...EXPECT VFR WITH
MORE OF A NORTHWESTERLY FLOW AS A POORLY DEFINED FRONT SAGS SOUTH.
LOOK FOR CONVECTION TO REFIRE FRIDAY AFTERNOON.
EXTENDED OUTLOOK...SCATTERED SHOWERS AND STORMS POSSIBLE FRIDAY
AFTERNOON THROUGH THE EVENING HOURS. ISOLATED STORMS SATURDAY. VFR
SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM THURSDAY...PREVIOUS FORECAST REMAINS ON TRACK. LATEST
OBSERVATIONS FROM BUOYS AND COASTAL SITES SHOW GUSTS IN THE 25-30 KT
RANGE. WINDS SHOULD INCREASE ANOTHER 2-3 KNOTS THROUGH THE AFTERNOON
HOURS. SEAS ARE 8 FT OUT AT THE FRYING PAN SHOALS BUOY...AND AS HIGH
AS 6 FT AT THE OCEAN CREST PIER WAVE GAUGE. PREVIOUS DISCUSSION FROM
1030 AM FOLLOWS...
A TIGHT PRESSURE GRADIENT ALONG THE SOUTH SIDE OF LOW PRESSURE IN
VIRGINIA WILL MAINTAIN WINDY CONDITIONS ACROSS THE COASTAL WATERS
TODAY. SUSTAINED WINDS HAVE ALREADY REACHED 25 KT WITH GUSTS NEAR 30
KT AT THE FRYING PAN SHOALS WEATHER BUOY. SUSTAINED WINDS COULD
APPROACH 30 KT LATER THIS AFTERNOON AS THE CORE OF THE STRONGEST
WINDS MOVES ACROSS THE AREA. WIND SPEEDS SHOULD REMAIN JUST BELOW
GALE (34 KT) CRITERIA...BUT THIS SHOULD CERTAINLY BE THOUGHT OF AS A
"HIGH END" SMALL CRAFT ADVISORY. RADAR COMPOSITES SHOW A SQUALL LINE
ACROSS THE WESTERN CAROLINAS THAT SHOULD DIE OUT BEFORE MAKING IT
OFFSHORE THIS AFTERNOON. MODELS DO SHOW HOWEVER A SECOND UPPER
DISTURBANCE DIVING SOUTHEAST INTO THE REGION TONIGHT THAT MAY IGNITE
SOME SHOWERS AND STORMS...ESPECIALLY ACROSS THE NC WATERS.
SEAS HAVE BUILT AS HIGH AS 8 FEET OUT AT THE FRYING PAN SHOALS
BUOY...3-4 FT AT OUR NEARSHORE CORMP BUOYS. SEAS SHOULD BUILD
ANOTHER 1-2 FT BY LATE THIS AFTERNOON. WITH THE STRONG SOUTHWEST
WINDS CONTINUING.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SOUTHWEST FLOW OVER THE WATERS AT THE START OF
THE PERIOD WILL DECREASE AND BECOME HIGHLY VARIABLE AS COLD FRONT
DROPS IN FROM THE NORTH. APPEARS FRONT WILL STALL ACROSS THE
WATERS...NEAR CAPE FEAR. THE RESULT BEING LIGHT WINDS WITH A
NORTHERLY COMPONENT ON THE NORTH SIDE OF THE FRONT AND WHILE LIGHT
SOUTHERLY WINDS ARE FOUND SOUTH OF THE BOUNDARY. STALLED BOUNDARY
LIFTS NORTH AS A WARM FRONT FRI NIGHT WITH SOUTHERLY FLOW DEVELOPING
ACROSS ALL WATERS EARLY SAT. GRADIENT BECOMES PINCHED LATE SAT AND
SAT NIGHT WITH SPEEDS INCREASING TO 15 TO 20 KT BY THE END OF THE
PERIOD. SEAS 3 TO 5 FT FRI MORNING SUBSIDING TO 2 TO 4 FT LATE FRI
INTO SAT BEFORE INCREASE IN WINDS SAT NIGHT RETURNS SEAS TO 3 TO 5
FT. MAIN WAVE COMPONENT WILL BE SOUTHERLY SWELL FROM PROLONGED SOUTH
TO SOUTHWEST WINDS. LIGHT NORTHEAST FLOW DEVELOPING FRI MAY ADD A
LITTLE CHOP TO NC WATERS.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...COLD FRONT WILL DROP SOUTH ACROSS THE WATERS
FROM THE NORTH ON SUN WITH HIGH PRESSURE BUILDING IN BEHIND THE
FRONT. BRIEF PERIOD OF SOUTHERLY FLOW SUN MORNING WILL BE REPLACED
BY NORTH TO NORTHEAST FLOW BY MIDDAY. INITIALLY GRADIENT WILL BE ON
THE WEAK SIDE WITH NORTH TO NORTHEAST FLOW AROUND 10 KT. COLD SURGE
SUN NIGHT AS THE HIGH PUSHES SOUTH HELPS TIGHTEN THE GRADIENT WITH
SPEEDS INCREASE TO 15 TO 20 KT AFTER MIDNIGHT. NORTHEAST FLOW
REMAINS 15 TO 20 KT INTO MON AFTERNOON BEFORE GRADIENT STARTS TO
RELAX AND SPEEDS DROP CLOSER TO 15 KT. SEAS START OUT 3 TO 4 FT BUT
ONCE NORTHEAST FLOW PICKS UP SUN NIGHT SEAS START TO BUILD.
HEADLINES MAY BE REQUIRED SUN NIGHT AND MON. DEVELOPING NORTHEAST
WIND WAVE ON TOP OF SOUTHERLY SWELL WILL CREATE CHAOTIC SEAS ON MON.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...43/TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1045 AM EDT THU APR 26 2012
.SYNOPSIS...
...STRONG AND GUSTY SOUTHWEST WINDS INTO THIS EVENING...STRONG LOW
PRESSURE WILL PASS TO OUR NORTH TODAY...ACCOMPANIED BY STRONG WINDS.
SCATTERED THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING COULD BRING
EVEN STRONGER WIND GUSTS...ESPECIALLY ACROSS NORTH CAROLINA. A COLD
FRONT WILL DIP INTO THE COASTAL CAROLINAS LATE TONIGHT... STALLING
FRIDAY...THEN LIFTING NORTH SATURDAY. THE FRONT WILL RETURN SOUTH
LATE SATURDAY NIGHT AS CANADIAN HIGH PRESSURE SURGES SOUTH ALONG THE
ATLANTIC COAST INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM THURSDAY...SURFACE LOW PRESSURE IN OHIO WILL MOVE INTO
NEW ENGLAND TONIGHT...AS A SECONDARY LOW DEVELOPS ACROSS VIRGINIA
AND MOVES OFFSHORE THIS EVENING. BOTH OF THESE LOWS ARE THE RESULT
OF UPPER DISTURBANCES: A STRONG ONE OVER LAKE SUPERIOR AND A WEAKER
ONE MOVING INTO THE VIRGINIA/NC MOUNTAINS THIS MORNING.
AN IMPRESSIVE SQUALL LINE ACROSS THE SOUTHERN APPALACHIANS THIS
MORNING HAS PUSHED EAST OF THE MOUNTAINS AND TO INTERSTATE 77 AT THE
TIME OF THIS WRITING. EVEN THE HOURLY HRRR RUNS HAVE FAILED TO KEEP
UP WITH THE RAPID SOUTH AND EASTWARD MOTION OF THIS LINE. TYPICALLY
WE EXPECT ORGANIZED CONVECTIVE SYSTEMS TO WEAKEN DURING THE LATE
MORNING DUE TO DETERIORATION OF THE LOW-LEVEL JET AS SUNSHINE
STEEPENS LOW-LEVEL LAPSE RATES AND THE MOMENTUM OF THE JET BECOMES
DISTRIBUTED OVER A DEEPER LAYER DOWN TO THE SURFACE. THE HRRR SHOWS
WEAKENING OF THE LINE BETWEEN NOW AND 16Z/NOON EDT...BUT STILL
MAINTAINS AT LEAST SOME CONVECTIVE ACTIVITY ARRIVING IN THE
BENNETTSVILLE AND LUMBERTON AREAS BY 17-18Z/1-2 PM EDT. THE
ATMOSPHERE WILL BECOME MODERATELY UNSTABLE ACROSS THIS REGION WITH
SURFACE-BASED CAPE RISING TO 1500 J/KG...-5 LIFTED INDICES...AND
LITTLE CAPPING. FORECAST WIND PROFILES ALSO SHOW SUFFICIENT VERTICAL
SHEAR FOR ORGANIZED STORMS (0-6 KM BULK SHEAR 30-40 KT). ANY
ACTIVITY SHOULD MOVE EAST ACROSS INTERIOR SOUTHEAST NORTH CAROLINA
DURING THE AFTERNOON...WITH DAMAGING WIND GUSTS THE PRIMARY THREAT.
FARTHER SOUTH INTO SOUTH CAROLINA...A CONVECTIVE CAP BETWEEN 800-700
MB (6500-10000 FT AGL) WILL ACT TO INHIBIT STORM DEVELOPMENT AND
THERE IS A MUCH LOWER CHANCE OF STORMS HERE DURING THE DAYLIGHT
HOURS. EVEN THE SEABREEZE MAY NOT EXTEND HIGH ENOUGH INTO THE
ATMOSPHERE TO OVERCOME THIS CAP AND WE ARE MAINTAINING A DRY
FORECAST INTO LATE AFTERNOON AWAY FROM THE NORTH CAROLINA STATE LINE.
VERY BREEZY CONDITIONS ARE EXPECTED TODAY DUE TO A TIGHT PRESSURE
GRADIENT ALONG THE SOUTH SIDE OF THE DEVELOPING SURFACE LOW IN
VIRGINIA. RADAR WIND PROFILES SHOW 50 KT WINDS AS LOW AS 4000
FT AGL...AND 30-40 KT WINDS AT 1000-2000 FT AGL. STRONG INSOLATION
SHOULD STEEPEN LAPSE RATES SUFFICIENTLY TO BRING GUSTS TO 30 KT (35
MPH) TO THE SURFACE RATHER EASILY TODAY EVEN OUTSIDE OF
THUNDERSTORMS.
TONIGHT MODELS SHOW A SECOND UPPER DISTURBANCE DIVING SOUTHEAST
ACROSS THE AREA. EARLIER STORMS ACROSS CENTRAL NORTH CAROLINA SHOULD
HAVE SHARPENED UP A FRONTAL BOUNDARY WHICH MAY ACT TO PROVIDE A
LITTLE STRONGER FOCUS FOR STORMS AFTER DARK.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT IN THE AREA FRI WITH THE
LATEST GUIDANCE NOW STALLING THE FRONT ACROSS SOUTHERN PORTIONS OF
THE FORECAST AREA AT THE START OF THE PERIOD. FRONT SLOWLY LIFTS
NORTH LATER FRI INTO FRI NIGHT AS SURFACE WAVE AND SHORTWAVE ALOFT
MOVE EAST ACROSS THE AREA. FORECAST SOUNDINGS AND CROSS SECTIONS
SHOW A NARROW BAND OF DEEP MOISTURE LIFTING INTO THE AREA LATE FRI
NIGHT. WHILE THERE IS NO SURFACE BASED INSTABILITY TO SPEAK OF THERE
IS SOME ISENTROPIC LIFT ALONG THE FRONT COINCIDENT WITH DIVERGENCE
ALOFT. IT NOW APPEARS THE BEST PRECIP CHANCES WILL BE FRI NIGHT AS
THE FRONT LIFTS BACK NORTH AND WEAK SURFACE WAVE TRAVELS EAST. LACK
OF STRONG FORCING AND NOCTURNAL TIMING WILL LIKELY RESULT IN LIGHT
PATCHES OF RAIN OVERNIGHT...LOW CHANCE SHOULD COVER MOST OF THE AREA
WITH ONLY A COUPLE HUNDREDTHS OF QPF.
FORECAST FOR SAT REMAINS UP IN THE AIR. 00Z GFS PUSHES THE SURFACE
FRONT NORTH OF THE REGION AS WEAK 5H RIDGE BUILDS NORTH AND LOW
PRESSURE MOVES THROUGH THE KY VALLEY. HOWEVER THE NAM/CANADIAN/AND
12Z ECMWF KEEP THE FRONT STALLED IN THE AREA WITH SHOWERS AND
THUNDERSTORMS DEVELOPING IN THE AFTERNOON. GIVEN THE CONSENSUS
BETWEEN THE 00Z NAM/CANADIAN...12Z ECMWF AND HPC WILL FAVOR THE
WETTER COOLER SOLUTION FOR SAT. GOING TO INTRODUCE POP FOR SAT/SAT
NIGHT...THOUGH ONLY SLIGHT CHANCE FOR NOW AND KNOCK BACK TEMPS A
DEGREE OR TWO. HOWEVER...IF THE GFS SOLUTION IS THE CORRECT ONE
TEMPERATURES COULD BE 5 DEGREES WARMER SAT AFTERNOON WITH NO THREAT
OF PRECIP. FRONT EVENTUALLY PUSHES NORTH OF THE AREA LATE SAT OR SAT
NIGHT WITH WEAK WARM ADVECTION KEEPING TEMPERATURES ABOVE CLIMO
OVERNIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...BACKDOOR COLD FRONT WILL DROP SOUTH ACROSS THE
AREA SUN...FOLLOWED BY STRONG CANADIAN HIGH RIDGING DOWN THE COAST.
PASSAGE OF THE FRONT IS LOOKING LESS AND LESS LIKE A PRECIP EVENT.
DEEP WEST TO NORTHWEST FLOW AHEAD OF THE FRONT HELPS DRY THE
COLUMN...AIDED BY WEAK 5H RIDGE BUILDING OVER THE SOUTHEAST.
NORTHEAST FLOW CONTINUES MON INTO TUE WITH SURFACE HIGH WEDGING DOWN
THE EASTERN SEABOARD. SURFACE RIDGE AXIS STARTS TO SHIFT OFFSHORE
LATE TUE BUT IS INITIALLY SLOW TO MOVE SOUTHEAST OF THE AREA. RETURN
FLOW STARTS TO DEVELOP ON WED AS THE CENTER OF THE HIGH PUSHES
FARTHER OFF THE EAST COAST. DO SEE A HINT OF A WEAK COASTAL TROUGH
DEVELOP TUE NIGHT INTO WED BUT VERY DRY AIR IN PLACE MINIMIZES THE
THREAT OF PRECIP. PERIOD REMAINS DRY WITH SURFACE AND UPPER RIDGING
IN PLACE. TEMPERATURES SUN AHEAD OF THE FRONT SHOULD BE NEAR
CLIMO...BUT THEN MON AND TUE END UP BELOW CLIMO IN COOL NORTHEAST
FLOW. MON WILL LIKELY BE THE COOLEST DAY WITH SOME WARMING TUE AS
THE AIR MASS MODIFIES. RETURN FLOW AT THE END OF THE PERIOD WILL
RETURN TEMPS BACK TO CLIMO.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...STRONG LOW LEVEL JET WILL CAUSE SOME WIND SHEAR EARLY IN
THE PERIOD UNTIL MIXING PRODUCES STRONGER WINDS AT THE SURFACE.
TIGHT SOUTHWESTERLY GRADIENT WILL PRODUCE WIND GUSTS TO NEAR 30 KTS
TODAY. A SHORT WAVE MOVING INTO WESTERN NORTH CAROLINA WILL MOVE
INTO THE WESTERN TERMINALS BY MID AFTERNOON...REACHING THE COAST BY
LATE AFTERNOON. MODERATE UNCERTAINTY WITH RESPECT TO COVERAGE AND
TIMING. BRIEF HEAVY RAIN IS POSSIBLE. TONIGHT...SOME LINGERING
CONVECTION IS POSSIBLE...BUT SHOULD BE ISOLATED. WINDS WILL DIMINISH
A BIT...BUT SHOULD REMAIN AROUND 10-15 KTS.
EXTENDED OUTLOOK...VFR WITH LOW CHANCES OF PRECIPITATION THROUGH
THE PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM THURSDAY...A TIGHT PRESSURE GRADIENT ALONG THE SOUTH
SIDE OF LOW PRESSURE IN VIRGINIA WILL MAINTAIN WINDY CONDITIONS
ACROSS THE COASTAL WATERS TODAY. SUSTAINED WINDS HAVE ALREADY
REACHED 25 KT WITH GUSTS NEAR 30 KT AT THE FRYING PAN SHOALS WEATHER
BUOY. SUSTAINED WINDS COULD APPROACH 30 KT LATER THIS AFTERNOON AS
THE CORE OF THE STRONGEST WINDS MOVES ACROSS THE AREA. WIND SPEEDS
SHOULD REMAIN JUST BELOW GALE (34 KT) CRITERIA...BUT THIS SHOULD
CERTAINLY BE THOUGHT OF AS A "HIGH END" SMALL CRAFT ADVISORY. RADAR
COMPOSITES SHOW A SQUALL LINE ACROSS THE WESTERN CAROLINAS THAT
SHOULD DIE OUT BEFORE MAKING IT OFFSHORE THIS AFTERNOON. MODELS DO
SHOW HOWEVER A SECOND UPPER DISTURBANCE DIVING SOUTHEAST INTO THE
REGION TONIGHT THAT MAY IGNITE SOME SHOWERS AND STORMS...ESPECIALLY
ACROSS THE NC WATERS.
SEAS HAVE BUILT AS HIGH AS 8 FEET OUT AT THE FRYING PAN SHOALS
BUOY...3-4 FT AT OUR NEARSHORE CORMP BUOYS. SEAS SHOULD BUILD
ANOTHER 1-2 FT BY LATE THIS AFTERNOON. WITH THE STRONG SOUTHWEST
WINDS CONTINUING.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...SOUTHWEST FLOW OVER THE WATERS AT THE START OF
THE PERIOD WILL DECREASE AND BECOME HIGHLY VARIABLE AS COLD FRONT
DROPS IN FROM THE NORTH. APPEARS FRONT WILL STALL ACROSS THE
WATERS...NEAR CAPE FEAR. THE RESULT BEING LIGHT WINDS WITH A
NORTHERLY COMPONENT ON THE NORTH SIDE OF THE FRONT AND WHILE LIGHT
SOUTHERLY WINDS ARE FOUND SOUTH OF THE BOUNDARY. STALLED BOUNDARY
LIFTS NORTH AS A WARM FRONT FRI NIGHT WITH SOUTHERLY FLOW DEVELOPING
ACROSS ALL WATERS EARLY SAT. GRADIENT BECOMES PINCHED LATE SAT AND
SAT NIGHT WITH SPEEDS INCREASING TO 15 TO 20 KT BY THE END OF THE
PERIOD. SEAS 3 TO 5 FT FRI MORNING SUBSIDING TO 2 TO 4 FT LATE FRI
INTO SAT BEFORE INCREASE IN WINDS SAT NIGHT RETURNS SEAS TO 3 TO 5
FT. MAIN WAVE COMPONENT WILL BE SOUTHERLY SWELL FROM PROLONGED SOUTH
TO SOUTHWEST WINDS. LIGHT NORTHEAST FLOW DEVELOPING FRI MAY ADD A
LITTLE CHOP TO NC WATERS.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...COLD FRONT WILL DROP SOUTH ACROSS THE WATERS
FROM THE NORTH ON SUN WITH HIGH PRESSURE BUILDING IN BEHIND THE
FRONT. BRIEF PERIOD OF SOUTHERLY FLOW SUN MORNING WILL BE REPLACED
BY NORTH TO NORTHEAST FLOW BY MIDDAY. INITIALLY GRADIENT WILL BE ON
THE WEAK SIDE WITH NORTH TO NORTHEAST FLOW AROUND 10 KT. COLD SURGE
SUN NIGHT AS THE HIGH PUSHES SOUTH HELPS TIGHTEN THE GRADIENT WITH
SPEEDS INCREASE TO 15 TO 20 KT AFTER MIDNIGHT. NORTHEAST FLOW
REMAINS 15 TO 20 KT INTO MON AFTERNOON BEFORE GRADIENT STARTS TO
RELAX AND SPEEDS DROP CLOSER TO 15 KT. SEAS START OUT 3 TO 4 FT BUT
ONCE NORTHEAST FLOW PICKS UP SUN NIGHT SEAS START TO BUILD.
HEADLINES MAY BE REQUIRED SUN NIGHT AND MON. DEVELOPING NORTHEAST
WIND WAVE ON TOP OF SOUTHERLY SWELL WILL CREATE CHAOTIC SEAS ON MON.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...III
LONG TERM...III
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
209 AM EDT THU APR 26 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE REGION LATE TONIGHT THROUGH
THURSDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES
ON FRIDAY. A WARM FRONT WILL DEVELOP JUST SOUTH OF THE REGION ON
SATURDAY.
&&
.NEAR TERM /UNTIL NOON TODAY/...
HAVE ADJUSTED TEMPERATURES DOWNWARD FOR TONIGHT AS THE RAIN COOLED
AIR NOTED BY THE HRRR MODEL MORE ACCURATELY REPRESENTS WHAT IS
BEING OBSERVED. THE PREVIOUS RISING TEMPERATURES WITH THE
SOUTHWEST WINDS ON THE WARM SIDE OF THE APPROACHING LOW WERE A BIT
TOO WARM FOR DAYBREAK TEMPERATURES. I BLENDED IN TOWARDS THE EARLY
AFTERNOON FOR TOMORROW AS MIXING WILL DEFINITELY LET THE AIRMASS
REACH THE WARMER READINGS WE HAVE IN FOR THIS TIME...ESPECIALLY IN
SOUTHERN CWA.
NORTHERN CWA WAS A LITTLE COOLER WITH THE OBSERVED TEMPERATURES
AND THIS ALSO WORKED WELL WITH THE HRRR READINGS THAT WERE
STRONGLY LEANED TOWARDS FOR THE NEXT 12 HOURS OR SO.
SOME MODELS WERE LINGERING PRECIP A BIT LONGER INTO THE MORNING
HOURS AND SEEING MORE RETURNS COMING IN FROM UPSTREAM I WAS
INCLINED TO LINGER LOW CHANCE PROBABILITIES OF SHOWERS THROUGH THE
MORNING IN THE EASTERN AND SERN CWA THROUGH ABOUT NOON...BLENDING
IN WITH A STRONG CUTOFF TO NO POPS BY THE AFTERNOON HOURS.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM FRIDAY/...
SOME SHOWERS AND THUNDERSTORMS MAY BE ONGOING AT THE BEGINNING OF
THE PERIOD. BUT THESE WILL COME TO AN END AS LOW PRESSURE OVER THE
AREA MOVES OFF TO THE EAST. MODELS SHOWING QUITE A BIT OF LOW
LEVEL MOISTURE LINGERING IN THE WAKE OF THE LOW. SO EXPECT CLOUDS
TO PERSIST THROUGH MUCH OF THE DAY. GRADIENT TIGHTENS BEHIND THE
LOW RESULTING IN STRENGTHENING WINDS. HOWEVER LOW LEVEL INVERSION
SHOULD LIMIT GUSTINESS. HIGH PRESSURE BUILDS IN THURSDAY NIGHT
WITH CLEARING. GFS MOS TEMPERATURES LOOKED REASONABLE FOR THE
MOST PART.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CONTINUED MANY OF THE SAME THEMES FROM YESTERDAY/S FORECAST AND
DISCUSSION. AT THE BEGINNING OF THE PERIOD /FRIDAY/...VERY AMPLIFIED
NRN STREAM CONTINUES WITH A VERY BLOCKY REGIME. SEVERAL PIECES OF
SHORTWAVE ENERGY ARE FOCUS...ONE BEING HEIGHT FALLS DIGGING INTO THE
PAC NW...THE OTHER BEING A DETERMINED SHORTWAVE ATTEMPTING TO
UNDERCUT THE LARGER SCALE BLOCKING RIDGE OFF TO ITS NORTH. THIS WAVE
WILL BE NEAR DENVER COLORADO ON FRIDAY MORNING...AND WILL DAMPEN
OUT/FLATTEN AS IT MOVES THROUGH THE MEAN RIDGE POSITION ON FRIDAY.
BY SATURDAY...NOT MUCH WILL REMAIN AS IT SHEARS INTO THE FLAT/FAST
FLOW WHICH IS THE BASE OF THE NERN CONUS LONGWAVE TROUGH.
THEREAFTER...UNCERTAINTY INCREASES IN THE PATTERN AS THERE HAS BEEN
A MIGRATION AWAY FROM THE MAINTENANCE OF THE NERN CONUS TROUGH...AND
VERY SLOW PROGRESSION EASTWARD OF THE HIGH-LATITUDE RIDGE OVER THE
NCNTL CONUS. THERE DOES SEEM ENOUGH AGREEMENT/CONFIDENCE TO BEGIN
WARMING EARLY NEXT WEEK MORE AGGRESSIVELY.
IN THE DETAILS...ISENTROPIC ASCENT/WARM ADVECTION WILL BEGIN WELL
ALOFT ON FRIDAY AFTERNOON OVER A VERY DRY BOUNDARY LAYER WHERE DWPTS
WILL BE IN THE 20S MOST AREAS. AS FLOW BACKS DOWNSTREAM OF THE
DAMPENING WAVE...MOISTURE WILL CONTINUE TO BE TRANSPORTED INTO THE
AREA AND THUS EXPECTED HIGH-BASED SHOWERS/AREAS OF RAIN TO STREAK
INTO IND/WRN OHIO BY LATE FRI AFTN OR FRI EVENING. A FAIRLY NICE
OVERRUNNING EVENT WILL THEN DEVELOP NORTH OF THE TIGHTENING
BAROCLINIC ZONE ON SATURDAY AND/OR SATURDAY NIGHT WITH A COLD RAIN
AMIDST NELY BOUNDARY LAYER FLOW...ESPECIALLY NRN FORECAST AREA.
25.12Z ECMWF HAS SLOWED A BIT WITH THIS WAVE/FORCING AND NOW PLACES
SATURDAY NIGHT AS THE BETTER RAIN CHANCES. THIS IS A CHANCE AND
DIFFERENCE FROM PREVIOUS/CONSENSUS RAINS...SO WILL CONTINUE TO FOCUS
ON SATURDAY AFTERNOON FOR BEST RAIN CHANCES. TEMPS WILL STRUGGLE
MIGHTILY IN THIS REGIME ESP NORTH OF I-70 TO GET MUCH ABOVE THE MID
40S. THE VERY TIGHT THERMAL GRADIENT /70S OVER CNTL KY/ WILL INDUCE
INSTABILITY AND LOW CONFIDENCE TEMP FORECAST ALONG/SOUTH OF OHIO
RIVER WHERE HIGHS IN THE 50S JUST AS POSSIBLE AS HIGHS IN THE 70S
DEPENDING ON WHERE FRONT SETS UP. AND THERE IS SLUG OF ELEVATED CAPE
ACROSS SRN FORECAST AREA SO CONTINUED THREAT OF STORMS IN THE SOUTH
ON SATURDAY.
EXPECT AS THIS WAVE SHIFTS THROUGH QUICKLY SAT NIGHT PRECIP ENDING
FROM NORTH TO SOUTH...AND SUNDAY TO BE DRY/COOL WITH AGAIN ANOTHER
INTRUSION OF NELY FLOW AND LOW DEWPOINTS. KEEPING THE FORECAST DRY
THROUGH MONDAY WITH SLOW WARMING. REMNANTS OF THE PAC NW/SWRN CANADA
HEIGHT FALLS FINALLY SLIDE INTO THE GREAT LAKES TUESDAY/WEDNESDAY
WITH THREAT OF STORMS. DID NOT WARM AS AGGRESSIVELY AS ECMWF/GFS MOS
GUIDANCE BUT DID TURN IT AROUND A LITTLE MORE QUICKLY FROM PREVIOUS
FORECAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
INITIAL BATCH OF CONVECTION HAS PUSHED THRU THE TAFS. ANOTHER
PATCH IS TRYING TO DEVELOP ALONG AND E OF I-75 ALONG A CONVERGENCE
BOUNDARY. THESE SHRA ARE EXPECTED TO MAINLY AFFECT CMH/LCK OVER
THE NEXT HOUR OR TWO.
EXCEPT FOR CMH/LCK...BACKED OFF ON THE MVFR CIGS FOR THE MOMENT. AS
SURFACE LOW APPROACHES LATER THIS MORNING...EXPECT IT BRING THE
MVFR CIGS TO ALL THE TAFS.
LOW AND CDFNT WILL CROSS THE TAFS FROM 10-12Z. WINDS WILL TURN TO
THE NORTHWEST AND INCREASE TO 10 TO 15 KT...GUSTING AS HIGH AS
25KT. REMNANT LOW LEVEL MOISTURE WILL KEEP MVFR CLOUDS ACROSS THE
AREA FOR MUCH OF THE DAY.
MVFR CIGS SHOULD DISSIPATE QUICKLY AROUND 00Z AS HIGH PRESSURE
BUILDS IN FROM THE NW.
OUTLOOK...SHOWERS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY NIGHT
THROUGH SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...FRANKS
SHORT TERM...
LONG TERM...BINAU
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1229 AM EDT THU APR 26 2012
.SYNOPSIS...
LOW PRESSURE WILL MOVE ACROSS THE REGION LATE TONIGHT THROUGH
THURSDAY MORNING. HIGH PRESSURE WILL BUILD IN FROM THE GREAT LAKES
ON FRIDAY. A WARM FRONT WILL DEVELOP JUST SOUTH OF THE REGION ON
SATURDAY.
&&
.NEAR TERM /UNTIL NOON TODAY/...
HAVE ADJUSTED TEMPERATURES DOWNWARD FOR TONIGHT AS THE RAIN COOLED
AIR NOTED BY THE HRRR MODEL MORE ACCURATELY REPRESENTS WHAT IS
BEING OBSERVED. THE PREVIOUS RISING TEMPERATURES WITH THE
SOUTHWEST WINDS ON THE WARM SIDE OF THE APPROACHING LOW WERE A BIT
TOO WARM FOR DAYBREAK TEMPERATURES. I BLENDED IN TOWARDS THE EARLY
AFTERNOON FOR TOMORROW AS MIXING WILL DEFINITELY LET THE AIRMASS
REACH THE WARMER READINGS WE HAVE IN FOR THIS TIME...ESPECIALLY IN
SOUTHERN CWA.
NORTHERN CWA WAS A LITTLE COOLER WITH THE OBSERVED TEMPERATURES
AND THIS ALSO WORKED WELL WITH THE HRRR READINGS THAT WERE
STRONGLY LEANED TOWARDS FOR THE NEXT 12 HOURS OR SO.
SOME MODELS WERE LINGERING PRECIP A BIT LONGER INTO THE MORNING
HOURS AND SEEING MORE RETURNS COMING IN FROM UPSTREAM I WAS
INCLINED TO LINGER LOW CHANCE PROBABILITIES OF SHOWERS THROUGH THE
MORNING IN THE EASTERN AND SERN CWA THROUGH ABOUT NOON...BLENDING
IN WITH A STRONG CUTOFF TO NO POPS BY THE AFTERNOON HOURS.
&&
.SHORT TERM /NOON TODAY THROUGH 6 PM FRIDAY/...
SOME SHOWERS AND THUNDERSTORMS MAY BE ONGOING AT THE BEGINNING OF
THE PERIOD. BUT THESE WILL COME TO AN END AS LOW PRESSURE OVER THE
AREA MOVES OFF TO THE EAST. MODELS SHOWING QUITE A BIT OF LOW
LEVEL MOISTURE LINGERING IN THE WAKE OF THE LOW. SO EXPECT CLOUDS
TO PERSIST THROUGH MUCH OF THE DAY. GRADIENT TIGHTENS BEHIND THE
LOW RESULTING IN STRENGTHENING WINDS. HOWEVER LOW LEVEL INVERSION
SHOULD LIMIT GUSTINESS. HIGH PRESSURE BUILDS IN THURSDAY NIGHT
WITH CLEARING. GFS MOS TEMPERATURES LOOKED REASONABLE FOR THE
MOST PART.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CONTINUED MANY OF THE SAME THEMES FROM YESTERDAY/S FORECAST AND
DISCUSSION. AT THE BEGINNING OF THE PERIOD /FRIDAY/...VERY AMPLIFIED
NRN STREAM CONTINUES WITH A VERY BLOCKY REGIME. SEVERAL PIECES OF
SHORTWAVE ENERGY ARE FOCUS...ONE BEING HEIGHT FALLS DIGGING INTO THE
PAC NW...THE OTHER BEING A DETERMINED SHORTWAVE ATTEMPTING TO
UNDERCUT THE LARGER SCALE BLOCKING RIDGE OFF TO ITS NORTH. THIS WAVE
WILL BE NEAR DENVER COLORADO ON FRIDAY MORNING...AND WILL DAMPEN
OUT/FLATTEN AS IT MOVES THROUGH THE MEAN RIDGE POSITION ON FRIDAY.
BY SATURDAY...NOT MUCH WILL REMAIN AS IT SHEARS INTO THE FLAT/FAST
FLOW WHICH IS THE BASE OF THE NERN CONUS LONGWAVE TROUGH.
THEREAFTER...UNCERTAINTY INCREASES IN THE PATTERN AS THERE HAS BEEN
A MIGRATION AWAY FROM THE MAINTENANCE OF THE NERN CONUS TROUGH...AND
VERY SLOW PROGRESSION EASTWARD OF THE HIGH-LATITUDE RIDGE OVER THE
NCNTL CONUS. THERE DOES SEEM ENOUGH AGREEMENT/CONFIDENCE TO BEGIN
WARMING EARLY NEXT WEEK MORE AGGRESSIVELY.
IN THE DETAILS...ISENTROPIC ASCENT/WARM ADVECTION WILL BEGIN WELL
ALOFT ON FRIDAY AFTERNOON OVER A VERY DRY BOUNDARY LAYER WHERE DWPTS
WILL BE IN THE 20S MOST AREAS. AS FLOW BACKS DOWNSTREAM OF THE
DAMPENING WAVE...MOISTURE WILL CONTINUE TO BE TRANSPORTED INTO THE
AREA AND THUS EXPECTED HIGH-BASED SHOWERS/AREAS OF RAIN TO STREAK
INTO IND/WRN OHIO BY LATE FRI AFTN OR FRI EVENING. A FAIRLY NICE
OVERRUNNING EVENT WILL THEN DEVELOP NORTH OF THE TIGHTENING
BAROCLINIC ZONE ON SATURDAY AND/OR SATURDAY NIGHT WITH A COLD RAIN
AMIDST NELY BOUNDARY LAYER FLOW...ESPECIALLY NRN FORECAST AREA.
25.12Z ECMWF HAS SLOWED A BIT WITH THIS WAVE/FORCING AND NOW PLACES
SATURDAY NIGHT AS THE BETTER RAIN CHANCES. THIS IS A CHANCE AND
DIFFERENCE FROM PREVIOUS/CONSENSUS RAINS...SO WILL CONTINUE TO FOCUS
ON SATURDAY AFTERNOON FOR BEST RAIN CHANCES. TEMPS WILL STRUGGLE
MIGHTILY IN THIS REGIME ESP NORTH OF I-70 TO GET MUCH ABOVE THE MID
40S. THE VERY TIGHT THERMAL GRADIENT /70S OVER CNTL KY/ WILL INDUCE
INSTABILITY AND LOW CONFIDENCE TEMP FORECAST ALONG/SOUTH OF OHIO
RIVER WHERE HIGHS IN THE 50S JUST AS POSSIBLE AS HIGHS IN THE 70S
DEPENDING ON WHERE FRONT SETS UP. AND THERE IS SLUG OF ELEVATED CAPE
ACROSS SRN FORECAST AREA SO CONTINUED THREAT OF STORMS IN THE SOUTH
ON SATURDAY.
EXPECT AS THIS WAVE SHIFTS THROUGH QUICKLY SAT NIGHT PRECIP ENDING
FROM NORTH TO SOUTH...AND SUNDAY TO BE DRY/COOL WITH AGAIN ANOTHER
INTRUSION OF NELY FLOW AND LOW DEWPOINTS. KEEPING THE FORECAST DRY
THROUGH MONDAY WITH SLOW WARMING. REMNANTS OF THE PAC NW/SWRN CANADA
HEIGHT FALLS FINALLY SLIDE INTO THE GREAT LAKES TUESDAY/WEDNESDAY
WITH THREAT OF STORMS. DID NOT WARM AS AGGRESSIVELY AS ECMWF/GFS MOS
GUIDANCE BUT DID TURN IT AROUND A LITTLE MORE QUICKLY FROM PREVIOUS
FORECAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A SURFACE LOW DEVELOPING AND PUSHING EAST ACROSS OUR AREA TONIGHT
WILL COMBINE WITH A WARM FRONT OVER OUR TO PRODUCE NUMEROUS
SHOWERS AND THUNDERSTORMS. MOST OF THE ACTIVITY IS EXPECTED TO
OCCUR BETWEEN 01Z AND 07Z TONIGHT ACROSS OUR TAF TERMINALS.
MAINLY MVFR...WITH ISOLATED IFR CONDITIONS WILL OCCUR IN HEAVIER
STORMS. AFTER 07Z...THE FOCUS OF THE HEAVIER ACTIVITY WILL SHIFT
SOUTHEAST OF THE TAF TERMINALS. AS THE SURFACE LOW MOVES OVER OUR
AREA LATE TONIGHT...CIGS WILL LOWER TO MVFR WITH SCATTERED SHOWERS
MOVING THROUGH THE AREA.
AFTER SUNRISE...SHOWERS WILL COME TO AN END ACROSS THE AREA. AROUND
THAT TIME...A COLD FRONT WILL PUSH SOUTHEASTWARD ACROSS THE
THE TERMINALS. THIS WILL CAUSE WINDS WILL VEER TO THE NORTHWEST AND
INCREASE TO 10 TO 15 KT...GUSTING AS HIGH AS 25KT. REMNANT LOW
LEVEL MOISTURE WILL KEEP MVFR CLOUDS ACROSS THE AREA FOR MUCH OF
THE DAY.
OUTLOOK...SHOWERS AND MVFR CIGS/VSBYS POSSIBLE FRIDAY NIGHT
THROUGH SATURDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...FRANKS
SHORT TERM...
LONG TERM...BINAU
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1103 AM EDT THU APR 26 2012
.SYNOPSIS...
A COMPLEX AREA OF LOW PRESSURE AND TRAILING COLD FRONT WILL CROSS
THE CENTRAL PENNSYLVANIA TODAY. EXPECT AN INCREASING CHANCE OF
SHOWERS ACROSS THE AREA THIS AFTERNOON. HIGH PRESSURE WILL SPREAD INTO THE
REGION TONIGHT AND FRIDAY BRINGING COOLER AND DRIER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
FRONTAL SYSTEM WITH BROKEN LINE OF SHOWERS HEADING INTO CWA LATE
THIS MORNING. NUDGED POPS WITH A BLEND OF HRRR AND NAM.
INSTABILITY MARGINAL AND WITH MINIMAL CHANCES OF THUNDER. LITTLE
ELSE CHANGED IN FORECAST AS QPF TEMPS AND WIND LOOK SOLID.
TONIGHT...A MUCH DRIER AIR MASS OVERSPREADS THE REGION IN WAKE OF
COLD FRONT WITH GEFS PWATS FALLING TO BTWN 1-2SD BLW NORMAL
TONIGHT. OVER THE BULK OF CENTRAL PA...THIS WILL RESULT IN
CLEARING SKIES. HOWEVER...AIR MASS WILL BE COLD ENOUGH TO SUPPORT
LAKE EFFECT STRATO-CU AND SCT -SHSN ACROSS THE NW MTNS THRU THE
NIGHT. NO ACCUMS MENTIONED...AS BULK OF ACTIVITY SHOULD DIE DOWN
BEFORE SFC TEMPS REACH FREEZING.
AS A SECONDARY LOW DEVELOPS ALONG THE NEW ENG COAST AND TRACKS NEWD
TWD THE MARITIMES...EXPECT A BREEZY THURS NGT AS GRADIENT TIGHTENS
WITH SFC RIDGE SHIFTING SEWD THRU THE GRT LKS. DESPITE THE CLOUD
COVER AND WINDS...NWP GUIDANCE INDICATES AIR MASS MAY BE COLD ENOUGH
TO PUSH TEMPS BLW FREEZING ACROSS THE ALLEGHENY MTNS. HAVE THUS
ISSUED A FREEZE WATCH FOR OUR NORTHERN AND WESTERN MTNS TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
SFC RIDGE AXIS WILL SHIFT EWD FM THE UPPER MIDWEST ON FRI REACHING
CENTRAL PA FRI NGT. THE MAIN FCST ISSUES FOR FRIDAY ARE FIRE
WEATHER DURING THE DAY AND FROST/FREEZE AT NIGHT. DEEP BLYR MIXING
WILL TAP STG WINDS ALOFT...AND LLVL CAA WILL HELP PROMOTE FQNT SFC
WNDS GUSTS BTWN 20-30KTS. THE DEEP BLYR MIXING SHOULD ALSO DROP
DEWPOINTS THRU THE AFTN WITH FCST RH VALUES FALLING INTO THE UPPER
20S TO LOW 30S OVER MUCH OF THE S-CENTRAL MTNS AND LOWER SUSQ
VLY. DEPENDING ON HOW MUCH RAIN FALLS OVER THIS AREA TDY...THERE
IS A GOOD CHANCE OF ELEVATED FIRE WEATHER CONDS TOMORROW AFTN.
THE FOCUS WILL SHIFT TO POTENTIAL FROST/FREEZE HEADLINES TOMORROW
NGT AS ENSEMBLE THREATS PAGE SHOWS A HIGH PROBABILITY/CONFIDENCE
IN FROST/FREEZE CONDS. THIS WILL LKLY BE THE FIRST OF SEVERAL
FROST/FREEZE HEADLINES ESPECIALLY FOR THE NRN MTNS. CONSIDERED
ISSUING A FREEZE WATCH FOR TOMORROW NGT BUT AFTER COLLABORATION
WILL JUST KEEP MENTION IN HWO.
CONFIDENCE IN THE FCST HAS DROPPED BELOW AVG THROUGH THE WEEKEND.
THIS IS MAINLY DUE TO INCREASING COMPLEXITIES IN THE LG SCALE
FLOW PATTERN. THERE ARE MULTIPLE FEATURES TO CONTEND WITH
INCLUDING THE EJECTION OF SW UPPER LOW ENERGY ON THURS...EVOLUTION
OF TROUGH-RIDGE CONFIGURATION OVR THE NRN PLAINS AND UPPER MS VLY
AND EVENTUAL INTERACTIONS WITH THE NERN CONUS TROUGH. FOLLOWED HPC
RECOMMENDATIONS VERY CLOSELY AS A RESULT AND BLENDED THE OP
ECMWF/CANADIAN GLOBAL WITH PREV FCST TO DERIVE TONIGHT`S NDFD
GRIDS. THESE MODELS SEEMED TO PROVIDE A BETTER INTERMEDIATE
TIMING/AMPLITUDE OF THE SERN CANADA/NE CONUS FLOW. THERE IS
CONSIDERABLE UNCERTAINTY IN THE SPECIFICS BUT FOLLOWING THE
PREFERRED SOLN YIELDS THE BEST CHC OF RAIN ON SAT AFTN BEFORE THE
E-W FNTL ZONE IS SHUNTED SWD ON SUN BY SPRAWLING CANADIAN HIGH
BECOMING ANCHORED OVER ONT/QUE. DAYTIME HIGHS WILL BE WELL BELOW
CLIMATE NORMALS ESPECIALLY ON SATURDAY.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
THE LATEST MEDIUM RANGE GUIDANCE SHOWS THE NERN CONUS TROF PUSHING
OFF THE ECOAST AS AN UPPER RIDGE SLIDES EWD FROM THE OH VLY AND
GRT LKS. FOLLOWING A COOL END TO THE MONTH OF APRIL...RETURN FLOW
AND RISING HEIGHTS WILL SPELL A WARMING TREND INTO EARLY MAY.
INDIVIDUAL SHORTWAVES...WHICH ARE VERY HARD TO RESOLVE AT THESE
RANGES...WILL MODULATE OPPORTUNITIES OF PCPN. INTRODUCED POPS
STARTING MONDAY NGT AND CARRIED SCHC/CHC THRU WED.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
LOW PRESSURE APPROACHING FROM THE MIDWEST WILL SPREAD LOWERING
CLOUDS ACROSS CENTRAL PA EARLY THIS MORNING AND EVEN A FEW
SPRINKLES ACROSS SOUTHERN PA. HOWEVER...DUE TO DRY AIR IN THE
LOW LEVELS EXPECT CIGS TO REMAIN VFR WITH A LGT SE WIND UNTIL LATE
MORNING.
AS LOW PRES NEARS THE AREA...EXPECT SHRA TO BECOME NUMEROUS WITH
WIDESPREAD MVFR CIGS LIKELY BY AFTN. TRAILING COLD FRONT WILL
SWEEP THRU THE AREA BTWN 21Z-01Z...ACCOMPANIED BY A WIND SHIFT
FROM THE S TO THE NW. FOR MUCH OF THE AREA...EXPECT CLEARING TO
DEVELOP AFTER PASSAGE OF THE COLD FRONT. HOWEVER...RESIDUAL LOW
LVL MOISTURE ASCENDING THE W MTNS MAY PRODUCE A PERIOD OF IFR CIGS
AT JST DURING THE EVENING HRS. AT BFD...MOISTURE FLOWING OFF OF LK
ERIE WILL LIKELY RESULT IN PERSISTENT MVFR STRATO-CU THRU 06Z.
OUTLOOK...
FRI...VFR.
SAT...CHC RAIN/LOW CIGS SOUTH...POSS MIX WITH SNOW LAURELS/SC MTNS.
SUN-MON...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
PAZ004>006-010>012-017-018-024-033-037-041-042.
&&
$$
SYNOPSIS...ROSS/STEINBUGL
NEAR TERM...ROSS/FITZGERALD
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
210 PM EDT THU APR 26 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE NORTH RESULTING IN
UNSETTLED WEATHER. THIS COLD FRONT IS EXPECTED TO BECOME
STATIONARY FROM WEST TO EAST ACROSS OUR AREA FRIDAY AND SATURDAY.
THE FRONT WILL MOVE OFF TO THE SOUTH ON SUNDAY AS A CANADIAN HIGH
BUILDS OVER THE REGION. THEN THE HIGH WILL LINGER THROUGH THE EARLY
PART OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 145 PM...ELEVATED CONVECTION ALREADY FIRING ALONG A LINGERING
BOUNDARY. ONE CLUSTER ENTERING THE CENTRAL NC MTNS...AND ANOTHER
ENTERING THE SOUTHERN CHARLOTTE METRO AREA. THERE IS ENUF INSTBY FOR
STORMS TO PRODUCE LARGE HAIL...BUT WIND THREAT PROBABLY SUBDUED DUE
TO THE COOL BL.
MEANWHILE...ATMOS CONTINUES TO DESTABILIZE ACRS KY/TN AHEAD OF AN
APPROACHING COLD FRONT. GUIDANCE IS MIXED ON HOW QUICKLY WE CAN
DEVELOP SBCAPE AND FURTHER DEVELOPMENT AWAY FROM THE BNDRY THIS
AFTN. I HAVE POPS GRADUALLY RAMPING UP FROM WEST TO EAST...PEAKING
EARLY EVENING THEN DIMINISHING OVERNIGHT.
THE SPC MESOANALYSIS PAGE SHOWS EFFECTIVE SHEAR OF 40-50 KTS WITH
MUCAPES 2000-3000+ J/KG ACRS KY/TN. AND THE RUC PROGS THIS
ENVIRONMENT TO PROPAGATE INTO THE AREA. THE BIG QUESTION IS HOW THE
BL WILL EVOLVE. THE LATEST FCST SNDGS SHOW SLOW EROSION OF COLD POOL
AND 100+ J/KG OF SBCIN. THE NEW DAY 1 CONVECTIVE OUTLOOK HAS THE
MTNS AND UPPER SAVANNAH VALLEY IN A SLIGHT...BUT NOT TO THE EAST.
HIGH RES MODELS DO NOT SHOW AS MUCH ORGANIZATION WITH THIS
AFTN/EVENINGS CONVECTION. SO HAIL MAY REMAIN THE MAIN THREAT...WITH
SOME WIND THREAT IN THE MTNS.
TEMPS WILL BE ABOVE NORMAL OVERNIGHT UNDER THE DEBRIS CLOUDINESS.
FRIDAY...MODELS CONTINUE THEIR TREND OF A MORE SOUTHERN PUSH OF THE
COLD FRONT. THEY ALSO AGREE ON DECENT INSTBY ALONG/SOUTH OF THE
BNDRY AS IT STARTS TO LIFT NORTH AS A WARM FRONT DURING THE AFTN.
TOOK A MODEL BLEND FOR POPS. THIS HIGHLIGHTS THE NE GA AND UPSTATE
ZONES. SPC DAY 2 OUTLOOK HAS A SEE TEXT 5% FOR THOSE AREAS. SHEAR
WILL BE WEAKER...BUT ANOTHER SHORTWAVE WILL RIPPLE THRU QUASI-ZONAL
FLOW DURING PEAK HEATING...WITH FCST SNDGS SHOWING LESS CIN THAN
TODAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 205 PM THURSDAY...A WEAK UPPER RIDGING WILL BUILD INTO THE
SOUTHEAST U.S. FRI NIGHT-SAT...THEN WEAKENS SLIGHTLY SAT NIGHT
BEFORE CONTINUING TO BUILD OVER THE AREA SUN. THE SFC BOUNDARY WILL
PUSH N AS A WARM FRONT FRI NIGHT-EARLY SAT WITH BEST FORCING N OF
THE CWA. WE KEPT SLIGHT CHC POPS OVER MAINLY THE MTNS AND N ZONES
THRU SAT. AS A SFC RIDGE BUILDS INTO THE AREA FROM THE NE WITH SE
SFC FLOW SETTING UP. UPSLOPE FORCING SHOULD BE ENOUGH TO MAINTAIN
SLIGHT CHC POPS THRU THE DAY SUN...MAINLY OVER THE MTNS. EXPECT
TEMPS ABOVE AVG SAT AND SUN WITH COLDER AIR PUSHING IN FROM THE NE
DURING THE DAY SUN TO KEEP TEMPS BELOW AVG IN THE FAR NE CWA IN THE
AFTN.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 205 PM THURSDAY...HEIGHTS RISE SUN NIGHT-MON AS UPPER TROF
MOVES OFF THE NE COAST AND UPPER RIDGE BUILDS INTO THE SE US. COLD
AIR DAMMING CONTINUES TO DEVELOP SUN NIGHT AND SETTLES OVER THE AREA
MON. STILL EXPECT ENOUGH LOW LVL MOISTURE AND FORCING FOR SLIGHT CHC
POPS ACROSS THE AREA. WEDGE WEAKENS TUE AND SFC BOUNDARY MOVES N OF
THE AREA AND STAYS N THRU THE PERIOD. THIS PUTS CWA BACK IN THE WARM
SECTOR SO WITH MOIST S FLOW DEVELOPING WE HELD ON TO MENTION OF
SLIGHT CHC OF MAINLY AFTN SHWRS AND TSTMS TUE-WED DEVELOPING MOIST
SLY FLOW AND DIURNAL INSTABILITY. TEMPS WILL BE BELOW AVG MON...THEN
BACK ABOVE AVG TUE-THU.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...MAIN CONCERN NEXT COUPLE OF HOURS WILL BE A SMALL LINE OF
CONVECTION TRACKING SOUTH OF THE TERMINAL. NOT EXPECTING A DIRECT
IMPACT ATTM...BUT THE SUBTLE BNDRY THIS ACTIVITY IS FIRING ALONG IS
SLOWLY DRIFTING NWD. SO ADDITIONAL DEVELOPMENT TO THE WEST MAY
AFFECT KCLT. OTHERWISE...EXPECT VFR WITH GUSTY SW WINDS THIS AFTN
AFTN. THERE MAY BE ANOTHER ROUND OF CONVECTION THIS EVENING...AS A
COLD FRONT WILL PUSH THRU THE AREA OVERNIGHT. CONFIDENCE IS TOO LOW
THIS TIME...BUT MOST LIKELY TIME OF IMPACT SHUD BE IN THE 00Z TO 06Z
TIME FRAME. WINDS WIL SHIFT NW BEHIND THE FRONT...THEN NE FRIDAY
MORNING AND REMAIN LIGHT. DEBRIS CLOUDINESS ASSOCIATED WITH THE
CONVECTION SHUD BE VFR.
ELSEWHERE...A CLUSTER OF STORMS ARE MOVING INTO THE CENTRAL NC MTNS
ATTM...AND WILL BE VCTS AT KAVL FOR NEXT COUPLE OF HOURS. CONVECTION
MAY START TO DEVELOP LATER THIS AFTN ACRS THE REMAINDER OF THE
AREA...SO VCTS WILL BE CARRIED. ANOTHER ROUND OF CONVECTION IS
EXPECTED TO AFFECT THE REGION LATE THIS AFTN THRU THE EVENING...AS A
COLD FRONT PUSHES THRU FROM THE NORTHWEST. CONVECTION SHUD WANE
AFTER 06Z AND WINDS WILL SHIFT TO N/NW BEHIND THE FRONT. DEBRIS
CLOUDINESS SHUD BE VFR.
OUTLOOK...A COLD FRONT WILL LINGER INVOF THE FORECAST AREA THRU
FRIDAY NIGHT. MAINLY PM SHOWERS/THUNDERSTORMS AND MORE WIDESPREAD
RESTRICTIONS WILL BE POSSIBLE FRI AFTN AND OVERNIGHT. THE FRONT
LIFTS NORTH SATURDAY...BUT THEN DROPS BACK IN SUNDAY. SO PERIODS OF
RESTRICTIONS IN CLOUDS/PRECIP EXPECTED THRU THE WEEKEND.
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...PAT
NEAR TERM...ARK
SHORT TERM...RB
LONG TERM...RB
AVIATION...ARK
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1156 PM CDT WED APR 25 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION...FOR 06Z AVIATION DISCUSSION.
PROGRESSIVE WRLY LLJ STRUCTURE WILL RESULT IN LLWS AT TAF SITES
AROUND 26/06Z-26/08Z. WITH NO NOTICEABLE SHWRS/TSTMS TO OUR NW...
WILL NOT MENTION SHWRS/TSTMS UNTIL AFTER 26/15Z. WITH THE COLD
FRONT SAGGING SWD INTO MID STATE BY 26/18Z...PROVIDING A FOCUSING
MECHANISM FOR SCT SHWRS/TSTMS...WITH LOCATION UNCERTAINTY...
THRU 27/02Z...WHEN DIURNAL INFLUENCES WEAKEN AND SHWRS DISSIPATE.
&&
.PREV DISCUSSION.../ISSUED 929 PM CDT WED APR 25 2012/
UPDATE...
LATEST WRF AND RUC SOLUTIONS NOT SHOWING MUCH IN THE WAY OF
REDEVELOPMENT ACROSS OUR SOUTHWESTERN COUNTIES. THE 18Z GFS RUN
DOES SHOW AN AREA OF CONVECTION MOVING ACROSS MUCH OF THE WESTERN
PORTIONS OF THE MID STATE AFTER 06Z. HOWEVER...THIS ACTIVITY IS IN
THE FORM OF AN MCS WHICH IS EXPECTED TO MOVE SOUTHEAST FROM MO.
LATEST RADAR IMAGERY IS NOT SHOWING MUCH IN THE WAY OF DEVELOPMENT THERE.
THEREFORE...WILL LOWER POPS...PARTICULARLY ACROSS SOUTHEASTERN
ZONES.
REMAINDER OF FCST LOOKS OK.
.PREV DISCUSSION.../ISSUED 656 PM CDT WED APR 25 2012/
UPDATE...FOR 00Z AVIATION DISCUSSION.
AVIATION...00Z AVIATION DISCUSSION.
WILL MENTION VCSH THRU 26/13Z PER CONFIDENCE IN OCCURRENCE/BUT LOCATION
UNCERTAINTY. PROGRESSIVE WRLY LLJ STRUCTURE WILL RESULT IN LLWS AT
TAF SITES AROUND 26/06Z-26/11Z. WITH SHORTWAVE EXPECTED TO MOVE INTO
MID STATE AFTER 26/06Z...WILL NOT MENTION TSRA UNTIL 26/06Z-26/10Z.
BELIEVE ACTIVITY WILL WEAKEN BY 26/13Z WITH IFR CEILING PREDOMINATE.
CEILINGS SHOULD LIFT INTO THE MVFR RANGE BY 26/15Z-26/16Z WITH A
COLD FRONT SAGGING SWD INTO MID STATE BY 26/18Z...PROVIDING A FOCUSING
MECHANISM FOR SCT SHWRS/TSTMS...WITH LOCATION UNCERTAINTY...THRU 26/24Z.
PREV DISCUSSION.../ISSUED 606 PM CDT WED APR 25 2012/
UPDATE...
FRONTAL BOUNDARY LOCATED WELL TO THE NW OF MIDDLE TN AND IS
LOCATED ACROSS NORTHERN MO AND SW THROUGH SRN KN. SHORTWAVE
IMPULSES AND NOT EXPECTED TO ARRIVE UNTIL LATE TONIGHT.
THUS...WITH A RATHER INACTIVE RADAR RIGHT NOW...WILL OPT TO ADJUST
THE ONE WORDING TO REFLECT AFT MIDNIGHT WORDING. THROUGH THIS
EVENING THE ACTIVITY LOOKS ISOLATED TO SCT AT BEST.
OTW...REMAINDER OF FCST APPEARS TO BE IN GOOD SHAPE. DEW POINTS
ACROSS THE AREA ARE IN THE LOWER 60S WHICH IS THE FCST LOW.
SOUTHERLY WIND FLOW OF 5-15 MPH EXPECTED TO CONTINUE OVERNIGHT.
WILL MAKE GRID ADJUSTMENTS TO INCREASE CLOUD COVERAGE ACROSS THE
SOUTH. ALSO...WILL INCLUDE A 6HR SPLIT OF THE WEATHER GRIDS.
UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 243 PM CDT WED APR 25 2012/
DISCUSSION...
WARM FRONT HAS LIFTED NORTH AND INTO KENTUCKY AT MID AFTERNOON. A
FEW SHOWERS AND ISOLATED THUNDERSTORMS HAVE DEVELOPED ALONG AND
SOUTH OF WARM FRONTAL BOUNDARY AND IN WESTERN KENTUCKY AND WESTERN
TENNESSEE THIS AFTERNOON. THIS HAS BEEN MAINLY WARM ADVECTION TYPE
SHOWERS AND STORMS. SURFACE TEMPS HAVE WARMED INTO THE 70S AT MANY
LOCATIONS WITH 83 AT NASHVILLE. MOISTURE IS INCREASING IN THE
LOWER LEVELS THIS AFTERNOON BUT SLOWLY WITH DEWPOINT TEMPS
CURRENTLY MOSTLY IN THE 50S.
AS UPPER LEVEL FLOW CONTINUES OUT OF THE NORTHWEST TONIGHT MID
STATE WILL BE IN WARM SECTOR WITH A CHANCE FOR SHOWERS AND
THUNDERSTORMS. BELIEVE A BETTER CHANCE WILL COME TOWARD MIDNIGHT
NEAR KENTUCKY BORDER AND EXPECT THIS ACTIVITY TO SINK SOUTHWARD
DURING THE LATE NIGHT. THIS IS DUE IN PART TO A SHORT WAVE THAT
WILL BE DROPPING SOUTHEAST EMBEDDED IN NORTHWEST FLOW ALOFT. A
WEAK COOL FRONT WILL ALSO APPROACH FROM THE NORTHWEST AND EXTEND
ALONG THE OHIO RIVER BACK DOWN THROUGH SOUTHEAST MISSOURI AROUND
12Z THURSDAY.
THINK BEST SEVERE THREAT WILL BE ACROSS OHIO VALLEY TONIGHT. COULD
SEE AN MCS DEVELOP THIS EVENING OVER CENTRAL AND SOUTHERN ILLINOIS
SO WILL KEEP AN EYE OUT TO THE NORTHWEST.
COOL FRONT PULLS UP ALONG TENNESSEE/KENTUCKY BORDER ON THURSDAY
THEN LIFTS BACK NORTH LATE IN THE DAY AS A WARM FRONT. SO EXPECT
TO SEE SCATTERED SHOWERS AND STORMS ON THURSDAY. IN FACT IT LOOKS
LIKE AN UNSETTLED PERIOD COMING UP FOR THE NEXT SEVERAL DAYS WITH
SHOWER AND STORM CHANCES.
LOOKS LIKE TEMPS WILL AVERAGE ABOVE CLIMATOLOGY FOR THE NEXT SEVEN
DAYS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
346 PM CDT THU APR 26 2012
.UPDATE...
HAVE UPDATED THE FORECAST AND PRODUCTS TO INCLUDE THE SEVERE
THUNDERSTORM WATCH THAT IS IN EFFECT FOR THE SOUTHWEST AND SOUTH-
CENTRAL TEXAS PANHANDLE AND NORTHERN SOUTH PLAINS UNTIL 10 PM. NO
OTHER CHANGES MADE ATTM.
&&
.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 / 20 0 10 10 20
TULIA 55 85 49 75 52 / 20 0 10 10 30
PLAINVIEW 56 85 51 76 55 / 20 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 / 20 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.
&&
$$
93/23
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
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 / 20 0 10 10 20
TULIA 55 85 49 75 52 / 20 0 10 10 30
PLAINVIEW 56 85 51 76 55 / 20 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 / 20 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.
&&
$$
93/23
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1236 PM CDT THU APR 26 2012
.AVIATION...
FOR THE 18Z KAMA TAF...EXPECT VFR CONDITIONS TO CONTINUE THROUGH THE
TAF PERIOD. THOUGH THERE IS A SLIGHT CHANCE FOR TSRA BETWEEN 18 AND
06Z...THINK THIS IS VERY UNLIKELY GIVEN THAT THE LATEST RUN OF THE
NAM AND HRRR MODELS SHOW THE CONVECTION STAYING WELL NW OF THE
TERMINAL. THIS BIGGEST THREAT FOR TSRA WOULD BE JUST AHEAD OF THE
PACIFIC COLD FRONT THAT SHOULD ARRIVE BETWEEN 03 AND 09Z...BUT EVEN
THIS SEEMS UNLIKELY SO WILL NOT MENTION ANY TSRA IN THE TAF FOR NOW.
WINDS WILL GENERALLY BE SOUTHEASTERLY UNTIL THE PACIFIC COLD FRONT
MOVES THROUGH TONIGHT...SHIFTING WINDS TO WESTERLY.
FOR THE 18Z KDHT AND KGUY TAFS...BIGGEST CONCERN WILL BE THE CHANCES
FOR TSRA THROUGH 12Z. THE HIGHEST RISK OF TSRA FOR KDHT SHOULD BE
BETWEEN 23 AND 03Z...THOUGH COULD SEE STORMS AS EARLY AS 21Z. AT
KGUY...THE HIGHEST RISK WILL BETWEEN 00 AND 03Z...BUT COULD LINGER
EVEN PAST 06Z. FOR NOW HAVE JUST MENTIONED TSRA WITH MVFR
CONDITIONS...THOUGH TSRAGR...STRONG GUSTY WINDS LEADING TO CONVECTIVE
LOW LEVEL WIND SHEAR...AND LOWER FLIGHT CATEGORIES WILL CERTAINLY BE
POSSIBLE WITH SOME OF THESE STORMS. AS WITH KAMA...EXPECT A SUDDEN
SHIFT TO WESTERLY WINDS WITH THE PACIFIC COLD FRONT THAT SHOULD MOVE
THROUGH BETWEEN 03 AND 09Z.
JOHNSON
&&
.PREV DISCUSSION... /ISSUED 702 AM CDT THU APR 26 2012/
AVIATION...
VFR CONDITIONS ARE TO PERSIST AT KAMA...KDHT...AND KGUY THROUGH
AT LEAST 21Z. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP OVER THE NORTHWESTERN PANHANDLE AND ADJACENT
AREAS OF NEW MEXICO AND THE WESTERN OKLAHOMA PANHANDLE...BY 3 TO
5 PM. NEAR MVFR RESTRICTIONS MAY ACCOMPANY THIS CONVECTION AT OR
AROUND THE KDHT AND KGUY SITES BETWEEN 26/22Z TO 27/04Z. TRENDS
CONCERNING THESE STORMS WILL BE MONITORED.
PREV DISCUSSION... /ISSUED 512 AM CDT THU APR 26 2012/
DISCUSSION...
CURRENTLY AN UPPER LEVEL LOW MOVING ONSHORE ALONG THE BAJA COAST AND
WILL BRING WITH IT THE NEXT CHANCE FOR PRECIPITATION FOR THE
PANHANDLES. DRYLINE ASSOCIATED WITH THIS SYSTEM WILL SET UP NEAR THE
TEXAS NEW MEXICO BORDER AND WILL PROVIDE A FOCUS FOR CONVECTION LATER
TODAY. MODELS HAVE DRASTICALLY MOVED THE DRYLINE TO THE WEST IN THE
PAST COUPLE OF RUNS AND THIS IS NOW CAUSING THE FOCUS FOR POTENTIALLY
SEVERE WEATHER TO BE IN THE WESTERN AND CENTRAL TEXAS AND OKLAHOMA
PANHANDLES. SPC HAS THE CENTRAL AND WESTERN PANHANDLES UNDER A SLIGHT
RISK FOR SEVERE WEATHER. CAPE VALUES ACROSS MUCH OF THE PANHANDLES IS
AOA 2000 J/KG AND 0-6KM BULK SHEAR NEAR 50 KTS. MAIN THREAT WITH
STORMS THAT DO DEVELOP EAST OF THE DRYLINE WILL BE LARGE HAIL
POSSIBLY 2 INCHES OR GREATER AS COLDER TEMPERATURES ALOFT WILL HELP
SUPPORT LARGE HAIL GROWTH. IN ADDITION TO THE HAIL THREAT DAMAGING
WINDS IS ALSO OF CONCERN ALONG WITH THE POSSIBILITY OF AN ISOLATED
TORNADO AS STORMS COULD INTERACT WITH THE REMNANTS OF A BOUNDARY IN
THE AREA. ANOTHER TOPIC OF CONCERN IS THE CAP OVER THE CENTRAL PARTS
OF THE PANHANDLES...IF THE STORMS CAN STAY ORGANIZED AND STRONG
ENOUGH THEY COULD POTENTIALLY BREAK THE CAP AND BE LONG LIVED AS THEY
MOVE ACROSS THE PANHANDLES.
AFTER THIS EVENING THINGS QUIET DOWN FOR A BIT AS THE UPPER LOW MOVES
NORTHEAST OVER NORTHERN KANSAS AND WE GET INTO MORE OF A ZONAL
PATTERN THROUGH THE EARLY PART OF THE WEEKEND. SUNDAY LOOKS TO BRING
ANOTHER CHANCE OF PRECIPITATION AS SOUTHEASTERLY WINDS LOOK TO MOVE
OVER A MOSTLY STATIONARY FRONT ALONG NORTH TEXAS. WINDS WILL BRING IN
MOISTURE AND CAUSE ISENTROPIC LIFT ACROSS THE AREA THAT COULD LEAD TO
SHOWERS AND THUNDERSTORMS ACROSS THE PANHANDLES. CLOUDY SKIES WILL BE
AROUND ON SUNDAY AND THIS WILL HELP COOL THINGS DOWN AND GET THE AREA
AWAY FROM RECORD BREAKING HEAT.
STARTING TUESDAY OF NEXT WEEK ZONAL FLOW WILL PERSIST AND THERE LOOKS
TO BE A SERIES OF WEAK WAVES IN THE MID AND UPPER LEVELS THAT COULD
BRING SOME MORE CHANCES OF RAIN NEXT WEEK...HOWEVER CONFIDENCE IN
THESE EVENTS BRINGING PRECIPITATION TO THE AREA IS LOW AT THIS TIME.
MOULTON
FIRE WEATHER...
THE FIRE WEATHER WATCH THAT WAS IN EFFECT HAS BEEN CANCELLED DUE TO
THE DRYLINE FORECASTED TO BE FURTHER WEST AND IT CAUSING HIGHER
RELATIVE HUMIDITIES AND LOWER WINDS. IF THE FAR WEST AND ESPECIALLY
SOUTHWEST TEXAS PANHANDLE DOES NOT RECEIVE PRECIPITATION THIS EVENING
ELEVATED OR CRITICAL FIRE WEATHER WEATHER WILL BE POSSIBLE ON FRIDAY.
THROUGH THE WEEKEND FIRE WEATHER WILL SUBSIDE AS RELATIVE HUMIDITIES
SHOULD REMAIN ABOVE 20 PERCENT ALONG WITH RELATIVELY LIGHT WINDS.
EA/MOULTON
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
16/15
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
628 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...TONIGHT AND SATURDAY
628 PM CDT FRI APR 27 2012
MAIN FORECAST CONCERNS ARE WIND GUSTS THIS EVENING...LOWERING
CEILINGS OVERNIGHT...AND PRECIPITATION THROUGH SATURDAY AFTERNOON.
TIGHT PRESSURE GRADIENT ASSOCIATED WITH LOW PRESSURE ACROSS THE CENTRAL
PLAINS AND CANADIAN HIGH PRESSURE WILL CONTINUE GUSTY EASTERLY
WINDS THROUGH THE MID TO LATE EVENING HOURS...MAINLY AT KRST.
GUSTS BETWEEN 35 AND 40 KTS HAVE BEEN REPORTED ACROSS PORTIONS OF
IOWA AND SOUTHERN MINNESOTA AND THE HIGHEST WIND GUSTS ARE
ASSOCIATED WITH PRECIPITATION BANDS AS THEY LIFT NORTHEAST TOWARDS
KRST. ALTHOUGH PRECIPITATION IS NOT REACHING THE GROUND
INITIALLY...EVAPORATIVE COOLING IN THE LOW-LEVELS IS SUFFICIENT TO
BRING HIGHER GUSTS DOWN. FIRST OF SUCH LINES IS EXPECTED TO REACH
KRST AROUND 00Z...THUS HAVE INCREASED WIND GUSTS TO 32 KTS. WILL
HAVE TO MONITOR THIS CLOSELY OVER THE NEXT FEW HOURS.
AS AN UPPER LEVEL SHORTWAVE LIFTS TOWARDS THE AREA...GENERAL
LOWERING IN CEILINGS IS ANTICIPATED...VFR CEILINGS THROUGH THE EARLY
OVERNIGHT HOURS...TO HIGH-END IFR / LOW-END MVFR BY 10-11Z. PLENTY
OF DRY AIR IN THE LOW-LEVELS WILL INITIALLY LIMIT PRECIPITATION...SO
HAVE DELAYED ONSET A FEW HOURS PER LATEST FORECAST SOUNDINGS.
REGARDING SNOW CHANCES...CONTINUED THE BRIEF PERIOD OF -RASN AT KRST
AS COOLING COLUMN ALOFT MAY ALLOW SNOW MIXING IN...MAINLY FROM
AROUND SUNRISE TO MID MORNING.
PRECIPITATION WILL TAPER OFF LATE IN THE FORECAST PERIOD...BUT WITH
AMPLE LOW-LEVEL MOISTURE...LOW CLOUDS / 1500 TO 2000 FT / ARE
POISED TO PERSIST THROUGH THE EVENING HOURS SATURDAY.
&&
.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.....ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
355 AM CDT THU APR 26 2012
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
355 AM CDT THU APR 26 2012
MAIN FORECAST CONCERNS THIS PACKAGE...LOWS AND FROST THREAT LATE
TONIGHT...RAIN CHANCES FRI THROUGH SAT NIGHT...SNOW POSSIBILITY
LATE FRI NIGHT/SAT MORNING.
06Z DATA ANALYSIS HAD LOW PRESSURE OVER CENTRAL IL AND A BROAD AREA
OF HIGH PRESSURE BUILDING SOUTH OUT OF NORTHERN MAN/SASKAT. WIND
FIELD ACROSS MN/WI INDICATED A FRONTAL BOUNDARY ON THE LEADING EDGE
OF THE HIGH FROM NORTH-CENTRAL WI TO FAR NORTHWEST IA...WITH LIGHT/
VARIABLE WINDS SOUTH OF THE BOUNDARY AND NORTH/NORTHWEST WINDS
GUSTING UP TO 20 KTS BEHIND THE BOUNDARY. LITTLE TEMP DIFFERENCE
ACROSS THE BOUNDARY...BUT MORE NORTH/NORTHEAST LOW LEVEL FLOW BEHIND
IT WERE ADVECTING STRATUS CLOUDS SOUTH ACROSS EASTERN MN/NORTHERN
WI. WIDE RANGE OF TEMPS ACROSS THE REGION THIS MORNING...AROUND 40
NEAR LK SUPERIOR TO MID 60S IN PARTS OF CENTRAL IA.
NO BIG ERRORS NOTED WITH 26.00Z MODEL INITIALIZATIONS...HOWEVER GFS
IS AGAIN SOME 5F TO 8F TOO HIGH WITH SFC DEW POINT OVER THE MID MS
VALLEY INTO THE SOUTHERN PLAINS. SOLUTIONS SIMILAR THRU TONIGHT
THEN DIVERGE WITH TIMING OF THE RAIN SPREADING INTO THE AREA FRI
THEN OUT OF THE AREA SAT/SAT NIGHT. DPROG/DT OF 500MB HGTS AT 26.00Z
SHOWED MODEL RUNS OF 24.00Z AND 25.00Z VERIFIED WELL ACROSS NOAM AND
OFF THE BC/OR/WA COAST BUT THE TREND WAS SLOWER WITH THE TROUGHING
APPROACHING SOUTHERN CA. MODELS COMING INTO BETTER/TIGHTER CONSENSUS
WITH THE SOUTHERN CA TROUGHING INTO CO/KS BY FRI MORNING...FAVORING
SLOWER OF THE EARLIER RUNS. TREND WAS SLOWER WITH THE EASTERN CONUS
TROUGH AS WELL. TREND THRU FRI/FRI NIGHT IS FOR MORE TROUGHING
OVER THE CENTRAL/NORTHERN ROCKIES WITH THE CO/KS ENERGY EJECTING
FURTHER NORTH INTO THE MID/UPPER MS VALLEY BY SAT MORNING. IMPROVING
CONSENSUS TROUGHING OVER THE NORTHEAST CONUS AND ROCKIES AND RIDGING
OVER THE MID/UPPER MS VALLEY INTO MAN/WESTERN ONT. WITH THE SHIFTS
BY FRI NIGHT...RUN-TO-RUN CONSISTENCY TAKES A HIT FOR FRI NIGHT THRU
SAT NIGHT. CHECK OF OBS VS. MODEL DATA AT 06Z SHOWED ALL QUITE GOOD
WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS...HOWEVER ALL
STRUGGLING A BIT WITH THE CLOUDS/MOISTURE SPREADING SOUTH ACROSS
MN/WI EARLY THIS MORNING. PER WV IMAGERY GFS/GEM/ECMWF LOOKED BETTER
WITH THE SHORTWAVE DETAILS ALONG/OFF THE WEST COAST. NO CLEAR MODEL
FAVORITE AGAIN AND WITH THE TREND TOWARD A TIGHTER CONSENSUS THRU
SAT NIGHT...FAVORED THE CONSENSUS. SHORT-TERM FCST CONFIDENCE GOOD
THRU TONIGHT...THEN AVERAGE FRI THRU SAT NIGHT WITH THE PRECIP
TIMING/LOCATION DIFFERENCES THAT APPEAR AMONG THE MODELS.
IN THE SHORT TERM...COOLER CAN HIGH PRESSURE WILL CONTINUE TO BUILD
SOUTH INTO THE UPPER MIDWEST TODAY. CLOUDS TO OUR NORTH WILL BE
PROBLEMATIC THIS MORNING BUT ALL MODELS INDICATE STRONGER 925-850MB
COLD ADVECTION/SUBSIDENCE/DRYING...LOW LEVEL ANTICYCLONIC FLOW AND
STEEP LOW LEVEL LAPSE RATES WILL ERODE/MIX OUT THE CLOUDS DURING
THE LATE MORNING/EARLY AFTERNOON. 925MB TEMPS IN THE +4C TO +8C
RANGE BY 00Z FRI...FOR A MUCH COOLER DAY OVER PORTIONS OF THE FCST
AREA AS THE HIGH BUILDS IN. STILL QUESTIONS ABOUT LOWS TONIGHT AND
FROST POTENTIAL OVER THE NORTHEAST 1/3 OF THE FCST AREA.
GOOD CONSENSUS FOR THE SFC RIDGE AXIS TO BUILD INTO EASTERN WI/LK MI
BY 12Z FRI. THIS WOULD ALLOW FOR A BIT MORE GRADIENT WIND ACROSS THE
FCST AREA THRU TONIGHT FOR BOUNDARY LAYER MIXING. MODELS ALL
CONTINUE TO INDICATE AN INCREASE OF HIGH LEVEL MOISTURE/CLOUDS OVER
THE AREA LATER TONIGHT AS MOISTURE AHEAD OF THE TROUGHING INTO CO/KS
BY FRI MORNING STREAMS INTO THE RIGHT ENTRANCE REGION OF A 120KT
JET MAX OVER THE GREAT LAKES. THIS WOULD LIMIT RADIATIONAL COOLING
LATER TONIGHT. LEFT PATCHY TO AREAS OF FROST IN THE GRIDS BETWEEN
05-13Z FRI BUT WILL HOLD OFF ON ANY POSSIBLE FROST HEADLINES AND LET
DAY CREW HAVE ANOTHER SET OF MODELS AND 12HRS OF OBS TO EVALUATE.
STRENGTHENING WARM ADVECTION/ISENTROPIC LIFT IN THE 700-500MB LAYER
ALONG WITH DEEPENING MOISTURE SPREAD INTO THE WEST END OF THE FCST
AREA LATE TONIGHT...UNDER THE RIGHT ENTRANCE REGION OF THE GREAT
LAKES JET MAX. BROAD ASCENT/SATURATION INDICATED IN THE 700-300MB
LAYER...WITH THE SFC-800MB LAYER REMAINING ON THE DRY SIDE...MUCH
LIKE LATE TUE NIGHT/WED MORNING WERE. CONTINUED A SMALL -SHRA CHANCE
OVER THE WEST END OF THE FCST LATE TONIGHT. MOISTURE/LIFT CONTINUE
TO SLOWLY INCREASE AND SPREAD NORTHEAST INTO THE FCST AREA FRI/FRI
NIGHT. STRONGEST/DEEPEST OF THIS REMAINS OVER THE CENTRAL/SOUTHWEST
PARTS OF THE FCST AREA FRI/FRI NIGHT AND INTO SAT. WITH THE SHIFT OF
THE MODEL CONSENSUS NORTHWARD WITH THE FORCING/MOISTURE AND A BROAD
BAND OF RA/SHRA...GRADUALLY RAISED RAIN CHANCES OVER THE SOUTHWEST
2/3 OF THE FCST AREA THRU FRI THEN RAISED THESE TO 60-80 PERCENT
THESE AREAS FRI NIGHT. WITH THE DRIER SFC-800MB AIRMASS...MODEL
SOUNDINGS INDICATE LOWER LEVEL EVAPORATIVE COOLING MAY ALLOW FOR A
MIX OF -RA/-SN OR SOME WET SNOW LATE TONIGHT INTO SAT MORNING ACROSS
MUCH OF THE FCST AREA. HOWEVER...THERE MAY BE ISSUES WITH ICE
INTRODUCTION INTO THE TOPS OF THE CLOUDS. SOUNDINGS SHOWING CLOUD
TOP TEMPS MAY BE AT OR WARMER THAN -10C AT 12Z SAT...WITH LITTLE OR
NO ICE IN THE CLOUDS AND PRECIP FALLING AS A COLD RAIN. DID LEAVE A
-RA/-SN MIX IN FCST GRIDS FOR LATE FRI NIGHT THRU 15Z SAT FOR THE
POSSIBILITY OF SOME SNOWFLAKES. ALL MODELS BUT GFS INDICATE WEAK
CONVERGENCE AND MOISTURE IN THE SFC-700MB TROUGH AXIS REMAIN OVER
THE AREA ON SAT...WITH SOME THIS LINGERING/CONTINUING TO WEAKEN OVER
THE AREA SAT NIGHT. RAISED PRECIP CHANCES INTO THE 25-65 PERCENT
RANGE /HIGHEST OVER THE SOUTHWEST 2/3 OF THE FCST AREA/ SAT AND
LINGERED A SMALL -RA CHANCE SAT NIGHT.
GENERALLY FAVORED A BLEND OF THE NUMERICAL GUIDANCE HIGHS/LOWS FOR
TONIGHT THRU SAT NIGHT.
.LONG TERM...SUNDAY THROUGH WEDNESDAY
355 AM CDT THU APR 26 2012
26.00Z MEDIUM RANGE MODELS IN GENERALLY GOOD AGREEMENT FOR SUN THRU
WED AS THE NORTHERN ROCKIES TROUGHING EVENTUALLY PROGRESSES EAST
ACROSS THE AREA MON...THEN WITH AN ACTIVE QUASI-ZONAL FLOW FLOW
ACROSS THE NORTHERN CONUS IN TO THE MIDDLE OF NEXT WEEK. APPEARS
BEST CHANCE FOR A DRY DAY IN THE DAY 4-7 PERIOD WILL BE SUN WITH
SHORTWAVE RIDGING ALOFT AND SFC HIGH PRESSURE OVER THE REGION.
FALLING HGTS ALOFT WITH THE TROUGH AND PIECES OF SHORTWAVE ENERGY
ROTATING THRU THE FLOW WILL BRING PERIODIC ROUNDS OF DEEPER
FORCING/LIFT ACROSS THE AREA IN THE MON-WED PERIOD. PLENTY OF MODEL
DETAIL/TIMING DIFFERENCES WITH THESE SHORTWAVE FEATURES AND LOWER
LEVEL MOISTURE/THERMO-DYNAMIC FORCING PARAMETERS BY MON-WED. WITH
SFC LOWS PASSING NORTH OF THE AREA TUE/WED AND DEEP SOUTH/SOUTHWEST
FLOW TAPPING INTO SOME GULF MOISTURE...INSTABILITY LOOKS TO INCREASE
OVER THE AREA FOR TUE/WED. AFTER A SHRA CHANCE MON ADDED MORE TSRA
TO THE FCST GRIDS FOR TUE/WED. TEMPS TO WARM THRU THE LONG TERM
PERIOD WITH RATHER PERSISTENT SOUTH/SOUTHWEST FLOW...BELOW NORMAL
SUN TO ABOVE NORMAL BY TUE/WED. MODEL/ENSEMBLE CONSENSUS DATA IN THE
DAY 4-7 FCST GRIDS HAS THIS WELL TRENDED FOR NOW.
&&
.AVIATION...THROUGH 06Z FRIDAY
1148 PM CDT WED APR 25 2012
A TROUGH OF LOW PRESSURE EXTENDS INTO CENTRAL MINNESOTA FROM AN
AREA OF LOW PRESSURE OVER WEST CENTRAL ILLINOIS. HIGH PRESSURE WAS
OVER CENTRAL CANADA WITH THE RIDGE AXIS EXTENDING SOUTH INTO NORTH
DAKOTA. ENOUGH OF A CYCLONIC FLOW EXISTS BETWEEN THESE TWO FEATURES
TO CONTINUE TO PRODUCE SOME CLOUDS OVER NORTHEAST MINNESOTA INTO
NORTHERN WISCONSIN. THESE CLOUDS HAVE BEEN TRYING TO WORK SOUTH
TOWARD THE AREA BUT AS THEY DUE THEY BECOME SCATTERED AND THEN
DISSIPATE. THROUGH THE NIGHT...THE CYCLONIC FLOW SHOULD GRADUALLY
SLIP SOUTH INTO THE AREA ALLOWING SOME OF THESE CLOUDS TO GET INTO
THE AREA. BOTH THE 26.00Z NAM AND 26.02Z RUC WANT TO BRING IN A
BROKEN MVFR TO VFR DECK FOR THE OVERNIGHT HOURS...BUT THIS LOOKS
OVER DONE BASED ON CURRENT SATELLITE TRENDS AND OBSERVATIONS. WILL
ONLY BRING IN SOME SCATTERED CLOUDS AND IF A CEILING DOES DEVELOP
WOULD EXPECT IT TO BE VFR. STEEP LOW LEVEL LAPSE RATES ARE ALSO
EXPECTED TO DEVELOP LATE TONIGHT AND PERSIST INTO THURSDAY AFTERNOON
ALLOWING SOME GUSTY NORTH WINDS TO DEVELOP AT BOTH SITES. EXPECT THE
GUSTS TO BE IN THE 20 TO 25 KNOT RANGE UNTIL THE SURFACE RIDGE
BUILDS IN ENOUGH THURSDAY AFTERNOON TO ALLOW THE WINDS TO SETTLE
DOWN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
355 AM CDT THU APR 26 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT WED APR 25 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
338 PM CDT WED APR 25 2012
AT 3 PM...A SURFACE LOW WAS LOCATED JUST WEST OF CHARLES CITY
IOWA. A WARM FRONT EXTENDED SOUTHEAST OF THIS LOW INTO CENTRAL
ILLINOIS...AND A COLD FRONT EXTENDED WEST ACROSS WEST-CENTRAL
IOWA. TEMPERATURES ACROSS WESTERN AND SOUTHERN IOWA HAVE WARMED
WELL INTO THE 80S. THERE WERE EVEN A FEW 90S. MEANWHILE NORTH OF
THE WARM FRONT...THE TEMPERATURES RANGED FROM THE 40S ACROSS
NORTHERN WISCONSIN TO THE 60S ACROSS MUCH OF OUR FORECAST AREA.
ML CAPES HAVE CLIMB UP TO 250 J/KG ACROSS NORTHEAST IOWA AND
SOUTHWEST WISCONSIN WHICH WAS JUST ENOUGH INSTABILITY FOR THE LOW
PRESSURE AREA TO GENERATE A FEW SHOWERS ACROSS THIS AREA. THE
LATEST HRRR AND SPC WRF SHOW THAT THESE SHOWERS WILL MOVE
SOUTHEAST OF THE AREA BY 6 PM. FURTHER TO THE NORTHWEST SOME
ADDITIONAL SHOWERS WERE MOVING EAST SOUTHEAST ACROSS NORTHERN
WISCONSIN. THESE SHOWERS WERE ASSOCIATED WITH A POTENTIAL
VORTICITY ANOMALY MOVING SOUTHEAST ACROSS NORTHERN AND EASTERN
WISCONSIN. THESE SHOWERS HAVE BEEN MAINLY EAST AND NORTH OF TAYLOR
COUNTY...SO JUST WENT DRY THERE FOR TONIGHT.
ON THURSDAY...HIGH PRESSURE WILL NOSE SOUTHWARD INTO THE UPPER
MISSISSIPPI RIVER VALLEY. WITH ABUNDANT SUNSHINE...MUCH OF THE
AREA WILL MIX UP TO AROUND 850 MB. AS THIS OCCURS...DRIER AIR FROM
ALOFT WILL MIX TO THE SURFACE. THIS WILL LOW THE DEW POINTS TO
AROUND 20 NORTH OF THE INTERSTATE 94 CORRIDOR...AND IN THE LOWER
AND MID 20S ACROSS THE REMAINDER OF THE AREA. THIS IS ABOUT 3 TO
5 DEGREES LOWER THAN THE MOS DEW POINTS.
ON THURSDAY NIGHT...THE DEW POINTS WILL REMAIN RATHER DRY. THIS
WILL ALLOW THE TEMPERATURES TO DROP OFF RATHER RAPIDLY ACROSS
CENTRAL AND NORTH-CENTRAL WISCONSIN. LOW TEMPERATURES ACROSS THIS
AREA WILL LIKELY FALL INTO THE MID AND UPPER 20S. WITH TEMPERATURE
AND DEW POINT SPREADS GREATER THAN 8F...CONCERNED THAT THERE WILL
BE NO FROST DEVELOPMENT. HOWEVER THESE TEMPERATURES WILL STILL BE
COLD ENOUGH TO CAUSE SOME DAMAGE TO UNPROTECTED FRUIT CROPS AND
COLD-SENSITIVE FLOWERS. MEANWHILE FURTHER WEST AND SOUTH...THERE
WILL INCREASE IN THE CLOUD COVER FROM THE LATE EVENING INTO THE
OVERNIGHT. THIS WILL TEMPER THE POTENTIAL FALL IN THE TEMPERATURES
AND FROST DEVELOPMENT IN THOSE AREAS.
FROM FRIDAY INTO SATURDAY...A LONG WAVE TROUGH WILL BE DIGGING
INTO THE WESTERN CONUS. AS THIS OCCURS...THE RIDGE WILL BE
AMPLIFYING ACROSS THE CENTRAL UNITED STATES AND CANADIAN PRAIRIES.
THIS PATTERN SHIFT STARTED TO DEVELOP LAST NIGHT AND CONTINUED
INTO TODAY. AS A RESULT...THE STRONG 800 TO 500 MB FRONTOGENESIS
HAS MOVED BACK NORTHWARD INTO SOUTHEAST MINNESOTA...NORTHEAST
IOWA...AND SOUTHERN HALF OF WISCONSIN. DUE TO THIS...THE
PRECIPITATION PROBABILITIES WERE RAISED AND MOVED NORTH. 25.12Z
GFS AND NAM/WRF BUFKIT SOUNDINGS SUGGEST THAT THE COLUMN WILL BE
COLD ENOUGH AND THERE WILL BE THE INTRODUCTION OF ICE CRYSTALS AT
TIMES FOR THE RAIN TO CHANGE OVER TO SNOW AT TIMES IN THESE AREAS.
THE 25.12Z ECMWF AND 25.18Z NAM/WRF ALSO SHOWS POSSIBILITY. HOWEVER
IT IS A BIT FURTHER NORTH AND EAST. THIS MAY SHIFT EVEN FURTHER
NORTHWEST IF THE TROUGH IN THE WESTERN CONUS DIGS EVEN MORE. SINCE
THE POSSIBILITY OF SNOW HAS BEEN CONSISTENT FOR THE LAST 3 MODEL
RUN...JUST INTRODUCED A CHANCE OF SNOW AT THIS TIME. IN ADDITION
WITH MORE PRECIPITATION AND CLOUD COVER EXPECTED...HIGH
TEMPERATURES FOR SATURDAY HAD TO BE COOLED A FEW MORE
DEGREES...AND THIS MAY NOT BE ENOUGH YET. THE FORECAST FOR THIS
TIME PERIOD WILL LIKELY REMAIN RATHER FLUENT UNTIL THIS SYSTEM IS
SAMPLED FULLY BY THE UPPER AIR NETWORK ON THURSDAY NIGHT.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
338 PM CDT WED APR 25 2012
ON SATURDAY NIGHT...WE MAY HAVE THE POTENTIAL FOR ANOTHER FROST OR
FREEZE AS A HIGH PRESSURE SYSTEM BUILD ACROSS THE REGION. THE MAIN
QUESTION AT THIS TIME IS HOW FAST WILL THE AREA CLEAR OUT AND WHEN
THE WINDS MAY DECOUPLE.
FROM MONDAY NIGHT THROUGH WEDNESDAY...THE 25.12Z MODELS CONTINUE
TO STRUGGLE ON THE TIMING OF A LONG WAVE TROUGH MOVING OUT OF THE
CENTRAL PLAINS. THE ECMWF IS ABOUT 12 HOURS SOONER THAN THE GFS
AND HAS ITS PRECIPITATION CHANCES RUNNING FROM MONDAY NIGHT INTO
TUESDAY. WITH THE MODELS CONTINUING TO STRUGGLE WITH ITS TIMING
JUST STAYED WITH THE ALL BLEND TIMING FOR NOW.
&&
.AVIATION...THROUGH 06Z FRIDAY
1148 PM CDT WED APR 25 2012
A TROUGH OF LOW PRESSURE EXTENDS INTO CENTRAL MINNESOTA FROM AN
AREA OF LOW PRESSURE OVER WEST CENTRAL ILLINOIS. HIGH PRESSURE WAS
OVER CENTRAL CANADA WITH THE RIDGE AXIS EXTENDING SOUTH INTO NORTH
DAKOTA. ENOUGH OF A CYCLONIC FLOW EXISTS BETWEEN THESE TWO
FEATURES TO CONTINUE TO PRODUCE SOME CLOUDS OVER NORTHEAST
MINNESOTA INTO NORTHERN WISCONSIN. THESE CLOUDS HAVE BEEN TRYING
TO WORK SOUTH TOWARD THE AREA BUT AS THEY DUE THEY BECOME
SCATTERED AND THEN DISSIPATE. THROUGH THE NIGHT...THE CYCLONIC
FLOW SHOULD GRADUALLY SLIP SOUTH INTO THE AREA ALLOWING SOME OF
THESE CLOUDS TO GET INTO THE AREA. BOTH THE 26.00Z NAM AND 26.02Z
RUC WANT TO BRING IN A BROKEN MVFR TO VFR DECK FOR THE OVERNIGHT
HOURS...BUT THIS LOOKS OVER DONE BASED ON CURRENT SATELLITE TRENDS
AND OBSERVATIONS. WILL ONLY BRING IN SOME SCATTERED CLOUDS AND IF A
CEILING DOES DEVELOP WOULD EXPECT IT TO BE VFR. STEEP LOW LEVEL
LAPSE RATES ARE ALSO EXPECTED TO DEVELOP LATE TONIGHT AND PERSIST
INTO THURSDAY AFTERNOON ALLOWING SOME GUSTY NORTH WINDS TO DEVELOP
AT BOTH SITES. EXPECT THE GUSTS TO BE IN THE 20 TO 25 KNOT RANGE
UNTIL THE SURFACE RIDGE BUILDS IN ENOUGH THURSDAY AFTERNOON TO
ALLOW THE WINDS TO SETTLE DOWN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
338 PM CDT WED APR 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS MIAMI FL
424 AM EDT SAT APR 28 2012
.DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH 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.
&&
.AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
&&
.MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
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 AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 72 80 73 / 50 50 40 40
FORT LAUDERDALE 81 72 80 72 / 60 60 60 40
MIAMI 81 71 80 72 / 60 60 60 40
NAPLES 85 69 84 69 / 40 30 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...14/MJB
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1214 AM CDT SAT APR 28 2012
...UPDATE TO AVIATION...
.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...
VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD WITH WINDS
TURNING FROM WEST...TO NORTHWEST...TO NORTHEAST BY SATURDAY
AFTERNOON. THERE IS A SMALL CHANCE FOR REDUCED VISIBILITY BETWEEN
09Z AND 13Z...BUT HAVE HIGHER CONFIDENCE IN VFR AT THIS TIME.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
200 AM EDT SAT APR 28 2012
.UPDATE...
ISSUED AT 200 AM EDT SAT APR 28 2012
MADE JUST A FEW ADJUSTMENTS TO THE PRE-DAWN FORECAST...MAINLY TO
LOWER POPS AS THE AREA REMAINS TOO DRY FOR ANY LIGHT RETURNS TO MAKE
IT TO THE SFC AND MEASURE. ALSO UPDATED THE T AND TD GRIDS FOR THE
LATEST OBS AND TRENDS.
UPDATE ISSUED AT 1053 PM EDT FRI APR 27 2012
THE WARM FRONT REMAINS POISED ACROSS THE TENNESSEE VALLEY. THIS WILL
BEGIN TO LIFT TO NORTH BETWEEN 06 AND 12Z...LIKELY STALLING ACROSS
THE MIDDLE OF EASTERN KENTUCKY DURING THE DAY ON SATURDAY. THE LATEST
00Z NAM IS SHOWING A LITTLE BIT OF PRECIPITATION ACROSS THE AREA
BETWEEN 09 AND 12Z...MOST LIKELY IN RESPONSE TO SOME ISENTROPIC LIFT
IN THE 700-800 MB LAYER ONCE AGAIN. THERE IS A LITTLE ELEVATED
INSTABILITY ASSOCIATED WITH THIS...HOWEVER THE SOUNDINGS LOOK
MARGINAL FOR THUNDER...SO WILL CONTINUE TO ONLY MENTION A FEW
SHOWERS. ONCE THIS FORCING RELAXES DURING SATURDAY MORNING...THERE
SHOULD BE A PRETTY GOOD LULL IN THE ACTIVITY UNTIL THE AFTERNOON
HOURS AS WE REMAIN CAPPED. AS SUCH...ADJUSTED SOME OF THE POPS DOWN A
BIT THROUGH SATURDAY MORNING...BEFORE RAMPING BACK UP DURING THE
AFTERNOON...AS A WEAK SHORT WAVE TROUGH APPROACHES OVER TOP THE
LINGERING SURFACE BOUNDARY. FORECAST LOWS RANGING FROM THE LOWER TO
MIDDLE 40S IN THE MORE SHELTERED VALLEYS IN FAR NORTHEASTERN
KENTUCKY...TO THE LOWER TO MIDDLE 50S WEST OF I-75 LOOK ON
TARGET...AND HAVE ONLY MADE SOME MINOR DIURNAL ADJUSTMENTS ACCORDING
TO THE LATEST OBSERVATIONS.
UPDATE ISSUED AT 753 PM EDT FRI APR 27 2012
AN AREA OF WEAKENING CONVECTION IS CURRENTLY MOVING ACROSS SOUTH
CENTRAL KENTUCKY. THIS APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC
LIFT IN THE 800-700 MB LAYER. THE HRRR MODEL WAS PICKING UP ON THIS
ACTIVITY FAIRLY WELL...DIMINISHING IT AS IT MOVES INTO EASTERN
KENTUCKY. LOCATIONS WEST OF I-75 MAY SEE A FEW SPRINKLES OUT OF
THIS...HOWEVER WITH SUCH DRY LOW LEVEL AIR IN PLACE...WOULD NOT
EXPECT ANYTHING MORE THAN THAT. FRESHENED UP THE REST OF THE HOURLY
DATA AND TRIED TO ACCOUNT FOR A LITTLE SHARPER TEMPERATURE DROP IN
THE NORTHEAST VALLEYS WITH AT LEAST MOSTLY CLEAR TO PARTLY CLOUDY
SKIES EXPECTED INTO EARLY THIS EVENING. WILL REASSESS THE FORECAST
LOWS AS WELL AS IF ANY CONVECTION CAN FIRE UP TOWARDS DAWN
ASSOCIATED WITH THE RETURN OF THE WARM FRONT A BIT LATER ON.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 307 PM EDT FRI APR 27 2012
SFC ANALYSIS AT 18Z SHOWS YESTERDAY/S COLD FRONT TEMPORARILY RESIDES
ACROSS THE DEEP SOUTH AS A QUASI STATIONARY BOUNDARY...WITH AN
INVERTED TROF ALONG THE FRONT RANGE OF THE ROCKIES. THESE TWO
FEATURES WILL BECOME THE MAIN PLAYERS FOR OUR WX OVER THE SHORT TERM
AS THE FRONT BEGINS TO LIFT BACK TO THE NORTH TONIGHT IN RESPONSE TO
AN AREA OF LOW PRESSURE EJECTING OUT OF THE ROCKIES AND INTO THE
CENTRAL PLAINS. TEMPS TONIGHT WILL BE SOMEWHAT CHALLENGING WITH
ANTICIPATED CLOUD COVER RETURNING FROM THE SOUTH ALONG WITH WARMER
AIR ADVECTING INTO THE REGION...AND UPPER 40S IN THE NORTH TO LOW 50S
IN THE SOUTH WILL NOT QUITE TELL THE WHOLE STORY AS LOWS COULD BE
REALIZED EARLY BEFORE TEMPS LEVEL OFF OR EVEN BEGIN TO CREEP BACK UP
AFTER MIDNIGHT...ESPECIALLY IN THE SOUTH.
12Z MODELS CONTINUE TO DEPICT DECENT ISENTROPIC ASCENT ALONG THE
BOUNDARY AS IT PUSHES NORTH INTO THE REGION LATER TONIGHT...HOWEVER
THE MODELS ARE NOT BEING VERY GENEROUS WITH THE DEEPER MOISTURE. FCST
SOUNDINGS POINT TOWARDS A CONSIDERABLE DRY LAYER BETWEEN H9 AND H7
THRU MOST OF THE OVERNIGHT AND IF PUSH CAME TO SHOVE...CURRENT PROGS
WOULD NOT REALLY SUPPORT ANY PRECIP THRU 12Z BUT WITH A RETURN FLOW
REGIME COMMENCING AND A LEGITIMATE BOUNDARY EXPECTED TO BEGIN NOSING
INTO THE AREA...WILL KEEP ISOLATED SHOWERS IN THE MIX FOR TONIGHT.
BETTER MID AND UPPER LEVEL DYNAMICS LOOK TO ARRIVE ON SATURDAY WITH A
MODEST 50 TO 60 MPH MID AND UPPER LEVEL JET OVERHEAD ALONG WITH A MID
LEVEL IMPULSE SCOOTING ALONG THE OHIO VALLEY AS THE WEAKENING SFC LOW
DRIFTS INTO THE MIDWEST...PULLING THE WARM FRONT FURTHER NORTH
TOWARDS...AND POSSIBLY ACROSS THE OHIO RIVER. PARTIALLY CLEARING
SKIES FROM SOUTH TO NORTH WILL LEAD TO INCREASING INSTABILITY THROUGH
THE LATE MORNING AND EARLY AFTERNOON AS TEMPS REBOUND INTO THE MID
AND UPPER 70S WITH DEW PTS MOISTENING INTO THE MID 50S. MODELS HAVE
BEEN CONSISTENTLY ADVERTISING ALL OF THE NECESSARY INGREDIENTS FOR
DMC WITH A POTENTIAL FOR SOME STRONG TO SEVERE TSTMS DURING THE LATE
AFTERNOON AND EVENING. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREATS WITH ANY STORMS ON SATURDAY AFTERNOON...AND SPC HAS A GOOD
HANDLE ON ALL OF THIS WITH MOST OF ERN KY HIGHLIGHTED IN THE DY2.
CONVECTION SHOULD BEGIN TO LOOSE SOME OF ITS TEETH OVERNIGHT WITH THE
LOSS OF DAYTIME HEATING...THOUGH THE POTENTIAL FOR OUTFLOW BOUNDARIES
LOITERING ABOUT THE AREA OVERNIGHT SHOULD BE ENOUGH TO WARRANT A
THREAT FOR SCATTERED SHOWERS ALONG WITH ISOLATED RUMBLES THROUGH THE
REMAINDER OF THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 PM EDT FRI APR 27 2012
ON SUNDAY THE UPPER AIR STARTS OUT IN AN OMEGA LIKE PATTERN WITH AN
UPPER LOWS OVER THE WESTERN DAKOTAS AND NORTHEAST CANADA WITH A RIDE
EXTENDING FROM A HIGH OVER THE FLORIDA PANHANDLE EXTENDING NORTH
ACROSS INDIANA AND WISCONSIN AND THEN ENDING OVER NORTHERN MANITOBA.
THE PATTERN THEN TRIES TO MORPH INTO A ZONAL PATTERN. THE BOTTOM
LINE IS THAT THE STORM TRACK STAYS OVER OR NEAR THE AREA THROUGH THE
PERIOD. SO CONFIDENCE IS FAIRLY HIGH THAT THIS WILL BE A GENERALLY
ACTIVE WEATHER PATTERN WITH FREQUENT FRONTS AND TROUGHS MOVING
ACROSS THE AREA. THE HARD PART IS THE TIMING AND THIS IS WHERE THE
MODELS DIVERGE. IN ZONAL PATTERNS...SMALL SPEED DIFFERENCES CAN HAVE
GREAT DIFFERENCES IN TIMING.
IN GENERAL TRENDED THE MODEL BLEND TOWARD THE TIMING OF THE ECMWF.
WITH GREATER CONFIDENCE IN THE TIMING...THERE WOULD HAVE BEEN MORE
DRY PERIODS IN THE FORECAST...HOWEVER WITH THE TIMING
DIFFERENCES...SOME OF THE SYSTEMS TENDED TO BLUR TOGETHER. AFTER
SUNDAY...EASTERN KENTUCKY WILL BE IN THE WARM SECTOR AND
TEMPERATURES WILL STAY AT OR ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 200 AM EDT SAT APR 28 2012
VFR CONDITIONS SHOULD HOLD FOR THE BULK OF THE CWA THROUGH AT LEAST
DAWN...AS MAINLY MID AND HIGH LEVEL CLOUDS ADVECT IN FROM THE WEST. A
WARM FRONT WILL ENCROACH THE AREA FROM THE SOUTHWEST TOWARDS
DAWN...BRINGING IN LOWER CLOUD COVER...ALTHOUGH STILL GENERALLY ABOVE
3K FEET. THERE MAY BE SOME SCATTERED CONVECTION ASSOCIATED WITH THIS
AS IT MOVES NORTHEAST ACROSS THE FORECAST AREA...HOWEVER WILL
CONTINUE TO ONLY MENTION VCSH THROUGH 15Z AT THIS TIME. WINDS WILL
SHIFT TO THE SOUTHWEST BEHIND THE WARM FRONT AND BECOME GUSTY DURING
THE DAY. EXPECT ADDITIONAL SCATTERED STRONGER CONVECTION TO FIRE UP
IN THE AFTERNOON...PARTICULARLY NORTH OF THE MOUNTAIN PARKWAY...BUT
OUTFLOWS AND NEW DEVELOPMENT COULD IMPACT LOCATIONS FURTHER SOUTH
LATER IN THE AFTERNOON AND EARLY EVENING. FOLLOWING SUNSET THE WINDS
WILL SETTLE TO LIGHT AND VARIABLE IN MOST PLACES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...MB
LONG TERM....JJ
AVIATION...GEOGERIAN/GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
106 AM EDT SAT APR 28 2012
.Forecast Update...
Issued at 1245 AM EDT Sat Apr 28 2012
Sky cover has become variable across central Kentucky and southern
Indiana at this time, with skies ranging from mostly cloudy
(mid-high clouds) in east-central Kentucky to mostly clear over
parts of the remainder of central Kentucky. A generic partly cloudy
should due for the rest of the night as mid and high level clouds
remain transitory across the area. Showers have dissipated over the
lower Ohio Valley at this time. There could be isolated showers
develop toward morning, especially along and north of the Ohio River
elevated above the warm front. A better chance for precipitation
will wait til Saturday afternoon. Current hourly temperatures and
lows temperatures seem on track for now.
.Forecast Update...
Issued at 1057 PM EDT Apr 27 2012
Isentropic lift is currently generating some light showers across
the Ohio Valley. However, with dry air at low levels, only a few
isolated sprinkles will be possible. This will occur across mainly
the Bluegrass region for the next few hours. Then expect a dry
period before the next upper wave approaches from the west. This
should begin to spread precip into the Ohio Valley around the 08-09Z
time frame. The HRRR had a good handle on the afternoon/evening
precip in our south, and also depicts scattered showers mainly along
and north of the Ohio River arriving in the pre-dawn hours. Have
adjusted PoPs accordingly. Think the chance of thunder is very
minimal overnight, so have pulled it from the products. Updated
products have been issued.
Update issued at 645 PM EDT Apr 27 2012
Band of showers and thunderstorms are entering our western CWA. Have
increased PoPs across the west, with emphasis on our southwest.
Overall precip is diminishing and starting to dive southeast. Expect
scattered showers and thunderstorms across our southwest, with rain
showers and isolated thunder more likely further north. Then,
chances seem to become less as the precip shield behind this band
has diminished somewhat. Tried to reflect this over the next few
hours with the hourly grids. Updated products have been issued.
.Short Term (Tonight through Saturday night)...
Issued at 300 PM EDT Apr 27 2012
Low pressure over Kansas this evening will progress east into
northern Missouri by morning, lifting a warm front northward across
Tennessee. Showers and thunderstorms were occurring from the Plains
to the Ozarks ahead of this system Friday afternoon, and will move
to the northeast tonight. It appears that the bulk of the rain will
stay north of the Ohio River, where there will be stronger forcing
and deeper moisture. The best chance of showers in the LMK CWA will
be between 4am and 9am along and north of the river.
During the day Saturday the low will advance to the Louisville area
by evening and will pull its warm front up to about Interstate 64.
We should see a break in the precipitation after the morning
activity moves out and before any redevelopment occurs later in the
day. There is some question concerning storms tomorrow. Southern
Kentucky looks to stay well capped, and northern sections of the CWA
will stay capped through much of the day, until late in the
afternoon at Louisville and early evening at Lexington. Winds aloft
aren/t very strong, and the capping plus widespread leftover clouds
in the north behind the departing morning showers may hinder
destabilization. Deep moisture is somewhat lacking as well. At any
rate, it should take until late afternoon before storms can start to
reform. Hail looks to be the main threat from any storms, with wet
bulb zero heights around nine or ten thousand feet.
Shower and thunderstorm chances will continue into the evening hours
before diminishing late Saturday night. The warm front will likely
remain in the general vicinity.
Lows tonight should range from the upper 40s northeast to middle 50s
southwest. Highs tomorrow will be tricky with the front draped
right across the area...right now we`re going for lower 70s in the
north and lower 80s near the Tennessee border. Lows Saturday night
will be in the 50s.
.Long Term (Sunday through Friday)...
Issued at 300 PM EDT Apr 27 2012
By Monday night a ridge of high pressure will park itself over the
southeast United States, extending east into the Atlantic. This
will cause a persistent northerly flow of warm, moist air from the
Gulf of Mexico into the Tennessee and Ohio Valleys. Various
difficult-to-time disturbances both at the surface and aloft will
cross from the Plains into the northeastern U.S. and interact with
the moisture throughout the week and into the weekend, resulting in
a broken record forecast of scattered showers and storms throughout
the period. The week won`t be a washout...just occasional waves
of scattered convection.
The work week will be warm with highs in the 70s/80s Monday/Tuesday
and securely into the 80s from Wednesday into the weekend.
&&
.Aviation (06Z TAF Issuance)...
Updated at 100 AM EDT Sat Apr 28 2012
Skies at 05 UTC ranged from mostly cloudy over east-central Kentucky
to mostly clear over parts of the rest of central Kentucky. Clouds
were mid and high level causing little concern for aviation
purposes. Showers have dissipated at this time, and only isolated
showers appear possible the remainder of the night. Weak easterly
surface winds will continue north and east of the warm front.
On Saturday, warm front is expected to lift slowly northeast across
central Kentucky. Scattered thunderstorms are expected along and
near the front, with SDF and LEX having the best chance for
convection, especially in the afternoon to early evening. Conditions
should remain VFR at all TAF sites throughout the forecast period,
except temporarily MVFR in any thunderstorms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........TWF
Short Term.......13
Long Term........13
Aviation.........TWF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
242 AM CDT SAT APR 28 2012
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES SHOW AN
AMPLIFIED AND VISUALLY CONVOLUTED PATTERN ACROSS THE CONTINENT AT
THE CURRENT TIME. A CUTOFF UPPER LOW CIRCULATING OVER THE NORTHERN
ROCKIES IS WORKING TO EJECT A SHORTWAVE NORTH INTO SOUTHERN
MINNESOTA... WHICH IS HELPING TO PRODUCE THE BAND OF SHRA ACROSS
THE SOUTHERN PART OF THE FORECAST AREA AT THE CURRENT TIME.
HOWEVER... THIS FEATURE IS RUNNING INTO THE UPPER RIDGE WHICH
EXTENDS FROM CENTRAL SASKATCHEWAN SOUTHEAST THROUGH WISCONSIN...
WHICH IS SHEARING IT OUT WITH TIME AND WORKING TO DIMINISH THE
PCPN AS IT WORKS NORTHWARD. A SECONDARY SURGE OF PCPN WITH THE
UPPER TROUGH TO OUR SOUTH... COINCIDENT WITH BETTER MID-LEVEL
INSTABILITY... IS IN IOWA AND IS ALSO WORKING NORTHWARD WITH TIME.
THE LATEST HRRR AND HIGH RESOLUTION WINDOW RUNS SEEM TO HAVE A
DECENT HANDLE ON ALL OF THIS ACTIVITY... AND SUGGEST IT SHOULD
CONTINUE TO WORK UP INTO THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON... WITH ITS NORTHERN EDGE HAVING A TOUGH TIME MAKING IT
INTO THE NORTH CENTRAL AND NORTHEAST PORTION OF THE AREA GIVEN DRY
LOW LEVEL AIR BACK-FEEDING INTO THE REGION FROM THE SURFACE HIGH
POSITIONED TO OUR EAST. AS FAR AS THE LARGE SCALE PATTERN GOES...
OVERALL IT LOOKS TO DE-AMPLIFY AS WE HEAD INTO THE EARLY PART OF
NEXT WEEK... AS THE UPPER LOW TO OUR WEST SLIDES NORTH INTO CANADA
BY MONDAY AND SOMEWHAT ZONAL FLOW ESTABLISHES ITSELF OVER THE
NORTHERN TIER OF THE CONUS. HOWEVER... THE MEDIUM RANGE GUIDANCE
SUGGESTS SOME TROUGHING DEVELOPING TO OUR WEST BY MIDWEEK WHICH
WILL BRING SOME MORE ACTIVE WEATHER BACK INTO THE AREA BY MIDWEEK
INTO THE LATTER HALF OF THE WEEK. ON THE WHOLE... THE WEATHER WILL
BE SOMEWHAT UNSETTLED THROUGH THE UPCOMING WEEK... BUT AT THE
CURRENT TIME THE ONLY SYSTEM OF ANY PARTICULAR SIGNIFICANCE MAY BE
THE MIDWEEK FEATURE... WHICH COULD HAVE SOME INSTABILITY WITH
WHICH TO WORK AS IT MOVES ACROSS THE AREA ON WEDNESDAY.
AS ELUDED TO EARLIER... EXPECT TO SEE WIDESPREAD SHRA ACTIVITY
THIS MORNING AS SOME ISENTROPIC UPGLIDE WORKS TO SUSTAIN
THE ACTIVITY CURRENTLY MOVING IN FROM OUR SOUTH EVEN THOUGH THE
UPPER SUPPORT AND DPVA WILL BE FADING WITH TIME AS THE SHORTWAVE
CONTINUES TO SHEAR OUT. LOWEST CHANCES FOR MEASURABLE PCPN WILL
BE OVER THE NORTHEAST CWFA. THE SOUTHEAST CWFA COULD SEE SOME
THUNDER... BUT AT THIS POINT FORECAST 850-500MB DIFFERENTIAL
THETA-E VALUES FROM THE NAM AND GFS SUGGEST LEAVING THAT MENTION
OUT OF THE FORECAST. CURRENT TEMPERATURES ACROSS THE AREA... ALONG
WITH THE 00Z KMPX SOUNDING AND FORECAST SOUNDINGS FROM THE RUC...
SUGGEST IT WILL BE VERY DIFFICULT TO GET ANY SNOWFLAKES FROM THIS
ACTIVITY TODAY. NOT ONLY ARE TEMPERATURES IN THE BOTTOM THOUSAND
OR SO FEET QUITE WARM... BUT AN ELEVATED WARM LAYER IS STILL NOT
COMPLETELY VANQUISHED... AND THUS FAR THERE IS MINIMAL EVIDENCE
SUGGESTING THAT WILL OCCUR. SO... REMOVED ANY MENTION OF SNOW FROM
THE FORECAST FOR TODAY. SHOULD A SUFFICIENTLY HEAVY SHRA OCCUR IT
ISN/T OUT OF THE QUESTION THAT A FEW FLAKES COULD FIND THEIR WAY
TO THE GROUND... BUT ANY SUCH OCCURRENCE WOULD BE ISOLATED AND OF
NO IMPACT SINCE IT WOULD BE SHORT-LIVED AND NON-ACCUMULATING.
LINGERED SOME LOW CHANCE POPS INTO TONIGHT AS THE MID-LEVEL
BAROCLINIC ZONE AND DEEPER MOISTURE WASHES OUT OVER THE AREA. WE
SHOULD FIND OURSELVES SUFFICIENTLY DRY ON SUNDAY AS SOME MODEST
RIDGING SURFACE AND ALOFT BECOMES ESTABLISHED OVER THE AREA... SO
EXCLUDED POPS FROM THE SUNDAY FORECAST. HOWEVER... BY SUNDAY NIGHT
WE COULD SEE SOME LIGHT PCPN WORK ACROSS THE REGION AS THE UPPER
LOW CURRENTLY TO OUR WEST WORKS INTO SOUTHERN CANADA AND HELPS
DRAG A MID-LEVEL TROUGH THROUGH THE STATE ALONG WITH A WEAK
SURFACE TROUGH. THE BEST CHANCES FOR PCPN LOOK TO BE CLOSER TO THE
MAIN UPPER SYSTEM TO OUR NORTH AND CLOSER TO THE BETTER
INSTABILITY AND LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH AND
SOUTHEAST. HOWEVER... GIVEN SUFFICIENT DEEP LAYER MOISTURE AND
SOME WEAK FORCING... LOW POPS SEEM WARRANTED FOR MUCH OF THE AREA
SUNDAY NIGHT INTO MONDAY.
MADE MINIMAL CHANGES TO THE GOING FORECAST FROM MONDAY NIGHT
THROUGH FRIDAY... MEANING THERE CONTINUES TO BE A MENTION OF PCPN
EACH DAY. BY NO MEANS DOES THE ENTIRE PERIOD LOOK LIKE A
WASHOUT... BUT THERE IS SUFFICIENT SPREAD MODEL SOLUTIONS BOTH
WITH RESPECT TO TIMING AND AMPLITUDE OF FEATURES TO INCLUDE PCPN
CHANCES EACH DAY. AT THIS POINT... THE BEST CHANCE FOR WIDESPREAD
PCPN LOOKS TO BE TUESDAY NIGHT AND WEDNESDAY AS WE INITIALLY SEE
SOME HEALTHY RETURN FLOW AND WARM AIR ADVECTION... FOLLOWED BY THE
PASSAGE OF A SURFACE LOW AND ATTENDANT SHARP COLD FRONT THROUGH
THE REGION. AFTER THIS SYSTEM MOVES THROUGH... WE LOOK TO MAINTAIN
A BAROCLINIC ZONE NEARBY FOR THE NEXT FEW DAYS AS A FEW SUCCESSIVE
SHORTWAVES MIGRATE THROUGH ON FAIRLY QUICKLY WESTERLY MID-UPPER
LEVEL FLOW.
&&
.AVIATION.../06Z TAF ISSUANCE/
/ISSUED 1155 PM CDT FRI APR 27 2012/
DRY AIR IN THE LOWER LEVELS KEEPING MOST OF THE RAIN OVER
SOUTHWEST MINNESOTA AT THIS TIME...WITH JUST A VERY SLOW NORTHEAST
TREND OVERNIGHT PROBABLY REACHING KMSP/KSTC/KAXN BY AROUND 09Z-
10Z. CONSEQUENTLY...CIGS AND VSBYS REMAINING VFR MOST AREAS
OVERNIGHT WITH THE BETTER CHANCE OF MVFR AT KRWF. EXPECT THE RAIN
AND AT LEAST LOW LEVEL VFR TO EXPAND OVER THE MN PORTION OF THE
AREA DURING EARLY SATURDAY MORNING...AND THEN MVFR OVER MN SITES
LATE MORNING OR EARLY AFTERNOON. STILL A SLIGHT CHANCE OF A RAIN
AND SNOW MIX NOT ENOUGH CONFIDENCE TO MENTION IN TAFS. THE FORCING
FOR THE PRECIP GRADUALLY WEAKENS AND MOVES OFF TO THE NORTHEAST BY
EVENING BUT MVFR CIGS TO PERSIST OVER MN SITES WITH A SLIGHT
CHANCE OF IFR OVER KAXN. STILL BRISK EAST TO SOUTHEAST WINDS
OVERNIGHT INTO SATURDAY BUT DECREASING SATURDAY EVENING WITH THE
LOW PRES FILLING.
KMSP...VFR CIGS PERSISTING INTO THE OVERNIGHT HOURS BUT LOWERING TO
MVFR FROM 16-17Z WITH MORE PERSISTENT RAIN. THINKING THAT CIGS WILL
REMAIN ABOVE 017. RAIN DECREASING BY EVENING BUT CIGS REMAINING MVFR
WITH POSSIBILITY OF LEVELS DROPPING BLO 015 AFTER 06Z. GUSTY EAST
WINDS TO 24 KNOTS OVERNIGHT INTO SATURDAY BUT GUSTS ENDING AFTER
00Z.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
/JPR
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1203 AM CDT SAT APR 28 2012
.UPDATE...
ISSUED AT 922 PM CDT FRI APR 27 2012
MADE ADJUSTMENTS TO RAIN CHANCES AND TEMPERATURES THE REST OF THE
NIGHT INTO SATURDAY MORNING BASED ON CURRENT TRENDS. OVERALL AREAL
COVERAGE OF STORMS OVER EASTERN KANSAS AND WESTERN MISSOURI HAS
DECREASED THE LAST TWO HOURS. ONE EXCEPTION IS AN ISOLATED STORM
THAT RECENTLY DEVELOPED AND HAS BECOME SEVERE BETWEEN MKC AND JLN.
RUNS OF THE HRRR REFLECTIVITY OUTPUT HAS SHOWN CORRECTLY THE
OVERALL LACK OF PRECIPITATION THIS EVENING...AND SHOWS THAT STORMS
DEVELOPING OVER WESTERN MO WILL MOVE NORTHEAST WITH TIME. RUC RUNS
CONTINUE TO SHOW A MARKED INCREASE IN 925-850MB MOISTURE CONVERGENCE
OVER THE NORTHEASTERN HALF OF THE CWA BY 06Z ON THE NOSE OF A BROAD
45KT LOW LEVEL JET. HAVE LOWERED POPS A BIT OVER THE SOUTHERN PART
OF THE CWA AND MAINTAINED LIKELY POPS TO THE NORTH OF I-70 BETWEEN
05-09Z BEFORE THE LOW LEVEL MOISTURE CONVERGENCE LIFTS NORTHEASTWARD.
CONSEQUENTLY ONLY HAVE SLIGHT CHANCES LATE TONIGHT INTO EARLY SATURDAY
OVER THE WHOLE CWA BEFORE THE POTENTIAL FOR SCATTERED THUNDERSTORMS
INCREASES AHEAD OF THE SURFACE LOW AND ATTENDANT COLD FRONT FROM
14Z ONWARD.
TEMPERATURES WILL LIKELY REMAIN STEADY OR SLOWLY RISE OVER THE SOUTHERN
CWA LATER TONIGHT WHEN WARM FRONT LIFTS NORTH INTO THE AREA.
BRITT
&&
.SHORT TERM...
ISSUED AT 319 PM CDT FRI APR 27 2012
(TONIGHT)
DEALING WITH AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER
WESTERN/SOUTHWESTERN MO EARLIER THIS AFTERNOON AND IS TRACKING TO THE EAST
ACROSS FORECAST AREA AS OF 20Z. IT IS MOVING FAIRLY RAPIDLY AND SHOULD
BE EXITING AFTER 00Z. SO HAVE HIGHEST POPS OVER EASTERN PORTIONS
OF FORECAST AREA THIS EVENING. SOME CONCERN ABOUT ADDITIONAL DEVELOPMENT
AS SURFACE LOW TRACKS ACROSS AREA TONIGHT...SO KEPT HIGHEST POPS
NORTH OF SURFACE LOW TRACK...MAINLY OVER NORTHERN MO...INTO WEST
CENTRAL IL...BEFORE TAPERING OFF TOWARDS DAYBREAK. COULD SEE SOME
BRIEF HEAVY RAINFALL AND SMALL HAIL WITH SOME OF THE STRONGER STORMS.
OTHERWISE...DUE TO CLOUD COVER AND RAINFALL...TEMPS HAVE STRUGGLED
TO RISE MUCH TODAY...SO AS PCPN ENDS...COULD SEE TEMPS ACTUALLY
RISE A BIT BEFORE FALLING OFF. IT WILL BE CHILLY...WITH LOWS TONIGHT
IN THE UPPER 40S FAR NORTH TO THE UPPER 50S FAR SOUTH.
BYRD
&&
.LONG TERM...
ISSUED AT 319 PM CDT FRI APR 27 2012
(SATURDAY THROUGH FRIDAY)
MODELS CONTINUE TO HAVE DIFFERENT SOLUTIONS ON HOW TO HANDLE FRONTAL
BOUNDARY...WITH NAM HAVING BOUNDARY SINK SOUTH OF FORECAST AREA
DURING THE DAY ON SATURDAY...STALLING OUT JUST SOUTH OF FORECAST
AREA SATURDAY NIGHT AND SUNDAY. WHILE GFS/ECMWF HAS IT STALL OUT A
BIT FURTHER NORTH IN SOUTHERN PORTIONS OF FORECAST AREA. WILL LEAN
MORE TOWARDS GFS/ECMWF SOLUTION WITH BEST POPS ALONG AND SOUTH OF
I-70 THROUGH SUNDAY. THEN SUNDAY NIGHT AND MONDAY BETTER RAIN
CHANCES SHIFT TO THE NORTH AS NEXT IN A SERIES OF SHORTWAVES MOVES
ALONG FRONTAL BOUNDARY.
AS FOR TEMPS THROUGH THE PERIOD...SATURDAY WILL STILL BE RATHER
MILD...IN THE MID 60S FAR NORTH TO THE UPPER 70S SOUTH. THEN COOLER
AIR TO MAKE ITS WAY IN FOR THE LAST HALF OF THE WEEKEND BEFORE
MODERATING A BIT BY MONDAY. HIGHS ON SUNDAY WILL ONLY BE AROUND 60
FAR NORTH TO NEAR 70 FAR SOUTH...WARMING UP INTO THE UPPER 60S TO
MID 70S.
BEYOND THAT...WE REMAIN IN ACTIVE PATTERN WITH CHANCES OF SHOWERS
AND THUNDERSTORMS OFF AND ON THROUGH THE REST OF THE FORECAST
PERIOD. TEMPS TO CONTINUE MODERATING NEXT WEEK WITH HIGHS BACK IN
THE MID TO UPPER 70S BY TUESDAY...THEN WARMING UP INTO THE UPPER 70S
TO MID 80S THROUGH THE LAST HALF OF THE WORK WEEK.
BYRD
&&
.AVIATION...
ISSUED AT 1145 PM CDT FRI APR 27 2012
LOW PRESSURE OVER KANSAS IS MOVING EASTWARD TOWARD MISSOURI. A
BAND OF SHOWERS AND A FEW THUNDERSTORMS IS MOVING THROUGH
NORTHEAST MISSOURI AND THERE AREA ISOLATED SHOWERS AND STORMS OUT
AHEAD OF A WARM FRONT WHICH BE LIFTING INTO THE BI-STATE REGION
FROM SOUTHWEST MISSOURI. THERE APPEARS TO BE A SMALL WINDOW OF
OPPORTUNITY FOR ADDITIONAL THUNDERSTORM DEVELOPMENT AS MOIST AND
UNSTABLE AIR LIFTS OVER THE REGION BEFORE MORE STABLE AIR ALOFT
CAPS IT. WILL THEREFORE CONTINUE VCTS IN THE TERMINAL FORECASTS
ALONG THE I-70 CORRDIDOR. DO NOT SEE MUCH ADDITIONAL DEVELOPMENT
FOR THE QUINCY AREA OUTSIDE OF THE BAND MOVING THROUGH AT THIS
TIME. MVFR FLIGHT CONDITIONS WILL PREVAIL ACROSS PORTIONS OF THE
AREA AHEAD OF THE FRONT FOR A FEW HOURS. OTHERWISE...EXPCECT VFR
CONDTIONS TO PREVAIL. LOW LEVEL WIND SHEAR WILL BE A PROBLEM AS
THE STORM SYSTEM ALOFT MOVES ACROSS THE AREA AHEAD OF THE SURFACE
SYSTEM.
SPECIFICS FOR KSTL...
LOW PRESSURE OVER KANSAS IS MOVING EASTWARD TOWARD MISSOURI. THERE
APPEARS TO BE A SMALL WINDOW OF OPPORTUNITY FOR ADDITIONAL
THUNDERSTORM DEVELOPMENT AS MOIST AND UNSTABLE AIR LIFTS OVER THE
REGION BEFORE MORE STABLE AIR ALOFT CAPS IT. WILL THEREFORE
CONTINUE VCTS IN THE TERMINAL FORECAST FOR A FEW HOURS.
OTHERWISE...EXPCECT MVFR CONDTIONS TO PREVAIL FOR MUCH OF THE REST
OF THE NIGHT NORTH OF THE WARM FRONT. LOW LEVEL WIND SHEAR WILL BE A
PROBLEM AS THE STORM SYSTEM ALOFT MOVES ACROSS THE AREA AHEAD OF
THE SURFACE SYSTEM. COULD SEE THUNDERSTORMS AGAIN SATURDAY
AFTERNOON...BUT HAVE LEFT OUT FOR NOW. WILL LET SUBSEQUENT SHIFTS
TRY TO NAIL DOWN TIMING AND COVERAGE OF POTENTIAL THUNDERSTORMS.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
334 AM CDT SAT APR 28 2012
.SHORT TERM....TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
LINGERING DRY AIR OVER SRN WI RESULTING IN EVAPORATIVE COOLING AND
AREAS OF SLEET AND EVEN SOME SNOWFLAKES MIXED IN WITH THE LIGHT RAIN
EARLY THIS MORNING. LATEST RUC SOUNDINGS SHOW WET BULB ZERO
REMAINING NEAR OR SLIGHTLY BELOW FREEZING FOR A TIME EARLY THIS
MORNING UNTIL SATURATION OCCURS BETWEEN 10Z AND 15Z. BURST OF
STRONG Q-VECTOR CONVERGENCE AND IMPRESSIVE FN VECTOR RESPONSE TO
FRONTOGENESIS PUSHES IN DURING THIS TIME AS LOW LEVEL SATURATION
OCCURS. SFC TEMPS SHOULD REMAIN ABV FREEZING AS PRECIP SPREADS OVER
THE AREA...BUT NOT IMPOSSIBLE A BURST OF SLEET OR SNOW RESULTS IN
SOME MINOR ACCUMULATION ON GRASS EARLY THIS MRNG. WL NEED TO WATCH
THIS CLOSELY AND ISSUE FREQUENT SHORT TERM FORECASTS.
OTHERWISE...LOW LEVELS EXPECTED TO WARM AND SATURATE THIS MRNG AS
STRONG FORCING ASSOCIATED WITH VIGOROUS MID LEVEL SHORT WAVE OVER
IOWA PUSHES INTO SOUTHERN WI. IMPRESSIVE FN VECTOR RESPONSE TO
LAYER FRONTOGENESIS THIS MRNG WITH 10 TO 20 UNITS OF Q-VECTOR
CONVERGENCE. SHORT WAVE LOSES ITS VIGOR LATE THIS MRNG AND AFTN AS
IT RUNS INTO BUILDING MID LEVEL HIGH PRESSURE OVER THE WESTERN
GTLAKES AND THE CONTINUOUS FEED OF DRIER AIR. LINGERING WEAKENING
FORCING AND DEFORMATION WL RESULT IN AREAS OF -RA CONTINUING INTO
THE AFTN...BUT INTENSITY AND SPACIAL COVERAGE SHOULD BE SLOWLY
DIMINISHING. GRADUAL CLEARING IN THE NORTHERN CWA TONIGHT WL ALLOW
TEMPS TO FALL INTO THE LOW 30S WITH FROST POSSIBLE LATE.
.LONG TERM...SUNDAY...FORECAST CONFIDENCE HIGH.
MODELS IN GOOD AGREEMENT THAT SUFACE HIGH CENTERED NORTH OF GREAT
LAKES SUNDAY WILL DOMINATE THE REGION AND LIMIT CLOUDS AND KEEP
REGION DRY. LAKE MICHIGAN WATER TEMPS ARE MIDDLE TO UPPER 40S SO
EAST WINDS OFF LAKE MICHIGAN SUNDAY AND WILL KEEP SUNDAY HIGH TEMPS
NEAR 50 ALONG LAKESHORE TO UPPER 50S IN SOUTHCENTRAL AND SOUTHWEST
WISCONSIN.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FORCAST CONFIDENCE HIGH FOR
PRECIP CHANCES AND TYPE...MEDIUM FOR TIMING START AND END TIMES.
MODELS IN GOOD AGREEMENT MOVING SURFACE HIGH EAST OF THE AREA SUNDAY
NIGHT AND MONDAY WITH SOUTHERLY LOW LEVEL RETURN FLOW AND
APPROACHING UPPER LEVEL TROUGH BRINGING WARMER TEMPERTURES ALONG
WITH MOISTURE AND CLOUDS TO THE REGION SUNDAY NIGHT AND MONDAY. SOME
DISAGREEMENT ON TIMING OF START AND END OF PRECIPITATION...WITH NAM
SLOWER THAN EUROPEAN UKMET AND GFS WHICH START PRECIPITATION IN
SOUTHWEST WISCONSIN AROUND SUNDOWN SUNDAY AND MOVE AND INTENSIFY IT
ACROSS MOST OF THE STATE BY SUNRISE MONDAY AND CONINUE IT THROUGH
THE DAY MONDAY. PRECIPITATION DISSIPATES WEST TO EAST MONDAY NIGHT.
TEMPERATURES WARM ENOUGH THAT ALL PRECIPITATION WILL BE LIQUID WITH
HIGHEST PRECIPITATION AMOUNTS SOUTH OF I-94.
TUESDAY THROUGH SATURDAY. FORECAST CONFIDENCE MEDIUM.
SURFACE LOW OVER DAKOTAS AND MINNESOTA TUESDAY AND WEDNESDAY WILL
KEEP SOUTHERLY WINDS AND WARM TEMPERATURES...WITH HIGHS NEAR 70
TUESDAY AND MID 70S WEDNESDAY AND THURSDAY. UPPER TROUGH WEST OF THE
REGION WILL ALLOW SOUTHWEST FLOW WITH UPPER LEVEL DISTURBANCES
MOVING IN SOUTHWEST FLOW ACROSS THE REGION AND BRINGING CHANCE OF
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. BEST CHANCE OF
STRONG THUNDERSTORMS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH BEST
CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WHEN CAPE...BULK SHEAR
AND OTHER SEVERE INDICIES ARE AT A MAXIMUM FOR THE ENTIRE WEEK.
ADDITIONAL UPPER SHORT WAVES WILL CONTINUE UNSETTLED WEATHER THROUGH
SATURDAY WHEN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE REGION.
&&
.AVIATION/12Z TAFS/...NOT IMPOSSIBLE A BURST OF MODERATE SLEET OR
EVEN SNOW COULD BRIEFLY AFFECT TAF SITES EARLY THIS MORNING AS
STRONG FORCING WITH APPROACHING SHORT WAVE MOVES INTO SOUTHERN WI.
LINGERING DRY AIR RESULTING IN EVAPORATIVE COOLING AND MIX OF
PRECIP...SHOULD MOISTEN UP THIS MRNG...WITH PERIODS OF RA EXPCD
FOR MOST OF THE DAY. ONLY A LITTLE DRIZZLE POSSIBLE FOR A TIME
THIS EVENING DUE TO LINGERING MID-LEVEL DEFORMATION. CIGS SHOULD
LOWER TO IFR AND POSSIBLY LWR LATER THIS MORNING...GRADUALLY
LIFTING LATE TODAY AND TNGT.
&&
.MARINE...PRESSURE GRADIENT CONTINUES TO TIGHTEN OVER SOUTHERN LAKE
MI THIS MORNING AS LOW PRESSURE MOVES ACROSS NRN MO. GRADIENT WL
BEGIN TO RELAX LATER TODAY AND TONIGHT AS LOW WEAKENS TO THE
SOUTH...AND HIGH PRESSURE RIDGE BUILDS IN FROM THE NORTH. LOW LEVEL
UNSTABLE AIR MASS OVER THE LAKE SHOULD RESULT IN WINDS UP TO 30KTS
IN SRN MARINE ZONE...TRAILING OFF THE NORTH. WL CONTINUE SMALL
CRAFT ADVISORY FOR SRN 3 ZONES FOR TODAY AND TNGT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 4 AM CDT SUNDAY
FOR LMZ644>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...SLB
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1035 AM EDT SAT APR 28 2012
.UPDATE (TODAY AND TONIGHT)...
14Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS NORTHERN STREAM FLOW
EXTENDING FROM OVER THE 4-CORNERS REGION EASTWARD TO THE TN/OH
VALLEYS AND THEN OFF THE MID-ATLANTIC SEABOARD. CLOSER TO HOME...OUR
FORECAST AREA IS WEDGED BETWEEN UPPER LEVEL RIDGING ALONG THE
NORTHERN GULF COAST...AND A DISTURBANCE SPINNING OVER THE YUCATAN
CHANNEL/FL STRAITS. WV IMAGERY SHOWS THE MID/UPPER LEVEL MOISTURE IS
ADVANCING NORTHWARD AHEAD OF THIS DISTURBANCE AND IS RAPIDLY ERODING
THE DRY AIR CURRENTLY OVER THE FORECAST AREA. THIS ADVANCING
MOISTURE CAN BE SEEN IN SOME SIGNIFICANT DIFFERENCES BETWEEN THE 12Z
SOUNDING PROFILES FROM TAMPA AND MIAMI. THE KTBW SOUNDING STILL
SHOWS A FAIRLY DRY COLUMN ABOVE THE BOUNDARY LAYER WITH A PW UNDER
1". THE KMFL SOUNDING ON THE OTHER HAND IS QUITE MOIST THROUGH THE
COLUMN WITH A PW APPROACHING 2". MODEL GUIDANCE IS IN GOOD AGREEMENT
IN THE CONTINUED EROSION OF THE DRY AIR OVER OUR HEADS THROUGH THE
REMAINDER OF THE DAY...AND EXPECT OUR 00Z SOUNDING TO SHOW A
SIGNIFICANT JUMP IN PW.
AT THE SURFACE...RIDGE AXIS EXTENDS FROM OFF THE SOUTHEAST COAST
WESTWARD ALONG THE I-10 CORRIDOR. GRADIENT IS STILL RATHER LIGHT OVER
OUR REGION IN CLOSE PROXIMITY TO THE RIDGE AXIS. THIS LIGHT GRADIENT
SHOULD ALLOW BOTH EAST COAST AND WEST COAST SEA-BREEZE DEVELOPMENT
THIS AFTERNOON. VERY SUMMER-LIKE FEEL TO THE AIRMASS THIS MORNING
WITH TEMPERATURES RAPIDLY CLIMBING INTO THE 80S...AND DEWPOINT WELL
UP IN TO THE 60S TO NEAR 70.
INHERITED FORECAST IS IN GOOD SHAPE. MADE A MINOR CHANGE TO EXTEND
THE SLIGHT CHANCE POPS IN PLACE OVER THE SOUTHERN ZONES NORTHWARD
THROUGH THE TAMPA BAY AREA TO AROUND BROOKSVILLE. THE INCREASING
DEEP LAYER MOISTURE AND EVENTUAL SEA-BREEZE COLLISIONS SHOULD BE
ENOUGH TO FORCE AT LEAST ISOLATED CONVECTION LATE THIS AFTERNOON
INTO THE EVENING HOURS. IN FACT...ALL OF THE AVAILABLE HI-RES
CONVECTIVE ALLOWING MODELS PRODUCE ISOLATED TO SCT SHOWERS/STORMS
LATER TODAY. OVER OUR FAR NORTHERN/NATURE COAST ZONES...KEPT THE
POPS AT A SILENT 10% UNDERNEATH THE MORE PRONOUNCED SUPPRESSION FROM
THE UPPER RIDGE.
TONIGHT...A FEW EVENING STORMS WILL FADE WITH THE LOSS OF DIURNAL
HEATING AND SEA-BREEZE FOCUS WITHIN A FEW HOURS OF SUNSET. THE
REMAINDER OF THE NIGHT LOOKS QUIET WITH GENERALLY DRY CONDITIONS AND
SEASONABLE TEMPERATURES.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THIS AFTERNOON AND EVENING. INCREASING
HIGH CLOUDINESS WITH BKN CIGS 120-150 DEVELOPING THIS AFTERNOON WITH
SCT STRATO CU 040-050. SLIGHT CHANCE OF AN AFTERNOON/EVENING SHOWER
WITH LCL BKN040-050.
&&
.MARINE...
LIGHT EASTERLY WINDS WILL CONTINUE THROUGH THE WEEKEND WITH
AFTERNOON SEA BREEZES EXPECTED. WINDS AND SEAS WILL PICK UP
SOMEWHAT EARLY NEXT WEEK AS HIGH PRESSURE STRENGTHENS OVER THE
ATLANTIC.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 86 70 89 69 / 20 0 10 10
FMY 89 68 89 68 / 25 20 20 10
GIF 90 68 90 68 / 20 0 10 10
SRQ 86 69 88 69 / 20 10 10 10
BKV 88 63 90 63 / 15 0 0 10
SPG 86 72 86 72 / 20 0 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...14/MROCZKA
AVIATION...13/OGLESBY
AREA FORECAST DISCUSSION
NWS MIAMI FL
1002 AM EDT SAT APR 28 2012
.UPDATE...NOT QUITE SURE WHAT TO DO WITH CURRENT FCST CONSIDERING
HEAVIEST ACTIVITY REMAINING OFFSHORE. RADAR SIGNATURES CURRENTLY
INDICATE A SFC TROUGH MAY BE LOCATED FROM NEAR NASSAU TO HST AND
THEN EXTENDING INTO THE GOMEX. BOTH THE GFS AND ECMWF ARE THE
CLOSEST TO CURRENT TRENDS AND DO KEEP THE HEAVIEST CONVECTION OVER
THE BAHAMAS AND FLORIDA KEYS NEAR AND ALONG THE TROUGH AXIS. THE
GFS, NAM AND RAPID REFRESH ALL SHOW CONVECTIVE DEVELOPMENT OVER
INTERIOR S FL BY 18-19Z AND THEN MOVES TOWARDS THE W CST THROUGH
LATE AFTERNOON WHEREAS THE ECMWF IS MORE OF A BROAD BRUSH APPROACH.
SO BASED ON THE CURRENT TRENDS AND THE MODEL CONSENSUS SOLUTIONS
FOR THE REMAINDER OF THE DAY, WILL LOWER POPS SLIGHTLY FOR THE E
CST AND RAISE SLIGHTLY FOR COASTAL COLLIER.
KOB
&&
.PREV DISCUSSION... /ISSUED 638 AM EDT SAT APR 28 2012/
AVIATION...12Z ISSUANCE...LITTLE CHANGE FROM EARLIER DISCUSSION.
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS THE REGION AS A
TROUGH OF LOW PRESSURE FORMS IN THE CARIBBEAN. SCT SHRA AND A FEW
TSRA WILL IMPACT AN AREA BETWEEN KPBI AND KFLL THROUGH 13Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. ANTICIPATED TSRA COVERAGE TOO
LOW TO INCLUDE VCTS ATTM. WHILE CEILINGS AND VISIBILITIES WILL
REMAIN PREVAILING VFR, BRIEF INTERVALS OF MVFR-IFR ARE CERTAINLY
POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST SURFACE WINDS WILL
CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH OCCASIONAL HIGHER
GUSTS.
PREV DISCUSSION... /ISSUED 424 AM EDT SAT APR 28 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH 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.
AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
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 AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
638 AM EDT SAT APR 28 2012
.AVIATION...12Z ISSUANCE...LITTLE CHANGE FROM EARLIER DISCUSSION.
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS THE REGION AS A
TROUGH OF LOW PRESSURE FORMS IN THE CARIBBEAN. SCT SHRA AND A FEW
TSRA WILL IMPACT AN AREA BETWEEN KPBI AND KFLL THROUGH 13Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. ANTICIPATED TSRA COVERAGE TOO
LOW TO INCLUDE VCTS ATTM. WHILE CEILINGS AND VISIBILITIES WILL
REMAIN PREVAILING VFR, BRIEF INTERVALS OF MVFR-IFR ARE CERTAINLY
POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST SURFACE WINDS WILL
CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH OCCASIONAL HIGHER
GUSTS.
&&
.PREV DISCUSSION... /ISSUED 424 AM EDT SAT APR 28 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH 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.
AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
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 AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 72 80 73 / 50 50 40 40
FORT LAUDERDALE 81 72 80 72 / 60 60 60 40
MIAMI 81 71 80 72 / 60 60 60 40
NAPLES 85 69 84 69 / 40 30 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1022 AM CDT SAT APR 28 2012
.DISCUSSION...
ISSUED 1020 AM CDT SAT APR 28 2012
LATEST SURFACE MAP SHOWED WARM FRONT ROUGHLY ALONG A PITTSFIELD TO
LAWRENCEVILLE LINE. DEWPOINTS OF 55-60F SURGING IN FROM THE
SOUTHWEST BEHIND THE FRONT...WITH FLORA CURRENTLY UP TO 58F. SOME
CLEAR SKIES HAVE OCCURRED SOUTH OF THE FRONT AS WELL...HELPING TO
BOOST MUCAPES TO OVER 1000 J/KG ACCORDING TO LATEST SPC
MESOANALYSIS.
MAIN CONCERN FOR TODAY IS WITH CONVECTION. HIGH-RESOLUTION MODELS
AND 12Z NAM BRING THE FRONT TO NEAR THE I-72 CORRIDOR THIS
AFTERNOON...AS A WEAK SURFACE WAVE RIDES ALONG THE BOUNDARY. MOST
LIKELY LOCATION FOR CONVECTIVE INITIATION SHOULD BE AROUND SAINT
LOUIS...BEFORE FILLING IN SOUTH OF THE BOUNDARY INTO SOUTHEAST
ILLINOIS EARLY THIS AFTERNOON. SOUTHEAST CWA WILL BE WELL INTO THE
WARM SECTOR AS TEMPERATURES RISE INTO THE 70S AND DEWPOINTS REACH
60-65F...HELPING TO DESTABILIZE THINGS FURTHER AS RUC MUCAPES
REACH NEAR 3000 J/KG IN THAT AREA. SPC DAY1 SLIGHT RISK CONTINUES
ALONG AND SOUTH OF I-70.
NORTH OF THE FRONT...MOST PRECIPITATION THIS AFTERNOON SHOULD
MAINLY BE IN THE FORM OF SOME PATCHY DRIZZLE. SOME MODEST
TEMPERATURE RISES ARE EXPECTED...BUT HIGHS IN THE 50S WILL BE
COMMON NORTH OF I-74.
GEELHART
&&
.AVIATION...
ISSUED 631 AM CDT SAT APR 28 2012
CONTINUE SAME TREND OF LLWS THIS MORNING AS LOW LEVEL JET STILL
STRONG WITH SURFACE LOW OVER NORTHERN MO. AMPLE MOISTURE OVER
REGION WILL KEEP CIGS OVER REGION THROUGH DAY. DID ADD VCNTY TS
FOR SPI TAF DURING AFTERNOON...THOUGH BEST DEVELOPMENT CHANCES TO
BE SOUTHEAST OF SITE.
GOETSCH
&&
.PREV DISCUSSION...
ISSUED 313 AM CDT SAT APR 28 2012
RATHER COMPLICATED WEATHER PATTERN ACROSS MUCH OF THE COUNTRY THIS
MORNING. A LARGE STRONG SFC PRESSURE RIDGE FROM THE HUDSON BAY TO
THE MID ATLANTIC STATES BLOCKING THE RAPID ADVANCE OF A LOW MOVING
OUT OF THE PLAINS INTO THE MIDWEST THIS MORNING. DEEP UPPER LOW IN
ERN CANADA SLOWLY MOVING EASTWARD...AND SEVERAL MORE WAVES PROGGED
TO MOVE OUT OF THE WEST OFF OF A LOW IN THE NRN FRONT RANGE OF THE
ROCKIES. MODELS CONTINUE A RATHER WET BIAS THROUGHOUT THE
FORECAST...RESULTING IN MANY OCCURRENCES OF POPS FOR WHAT IS MORE
LIKELY TO BE SOME SHOWERY DAYS...WITH WIDESPREAD PRECIPITATION
SCARCE AT BEST.
SHORT TERM...TODAY THROUGH MONDAY...
MODELS HAVING A HARD TIME WITH THE CURRENT SITUATION AS THE LOW
MOVES NEWD INTO THE GREAT LAKES...WITH THE REMNANT BOUNDARIES LEFT
IN THE REGION AS THE LOW WEAKENS. SEVERAL SHORT WAVES EJECTED
AROUND THE DEEPER SYNOPTIC TROF TO THE WEST KEEPING THE PRECIP IN
THE REGION...INTERACTING WITH THE BOUNDARIES THROUGH THE WEEKEND.
THOUGH THE POPS ARE IN ALMOST EVERY PERIOD...IMPORTANT TO MENTION
THE MORE SHOWERY...AND NOT WIDESPREAD...NOR LONG DURATION
ANTICIPATED WITH THIS PRECIP EVENT. POSSIBILITY REMAINS THAT MUCH
OF THE FORECAST MAY END UP BETWEEN THE BEST PRECIP TO THE NORTH
AND SOUTH. HOWEVER...SOME CONCERN OUT THERE FOR SOME TS/SLIGHT
RISK OF SVR WEATHER IN THE SERN PORTION OF THE CWA THIS
AFTERNOON/EVENING...WITH MAX HEATING AND FRONT INTERACTING WITH
ANY SHORTWAVE MOVING THROUGH. MOSTLY AN ISSUE FOR HAIL/WIND...WITH
A BIT OF AN ISSUE FOR SOME MODERATE DEEP LAYER SHEAR. WET OFF AND
ON THROUGH THE WEEKEND...COOLER TODAY IN THE NORTH...AND
TEMPERATURES MODERATING SOMEWHAT TOMORROW WITH MORE EXTENSIVE
CLOUD COVER...AND THE FRONT JUST TO THE SOUTH POTENTIALLY WITH
RAIN COOLED AIR KEEPING THE WARMTH AT BAY. MONDAY PUSHING THE
FRONT A LITTLE FURTHER NORTH RESULTING IN WARMER TEMPS FOR THE SRN
PORTION OF THE STATE. HOWEVER...CONSIDERING THE UNRELIABILITY OF
THE MODELS OF LATE...HAVE AN ISSUE WITH CALLING THE LOCALE FOR THE
HIGHER POPS ALONG THE BOUNDARY. WILL REFRAIN...KEEP MORE GENERAL
POPS IN...AND ADD DETAIL AS THE MODELS COME INTO AGREEMENT.
LONG TERM...TUESDAY THROUGH FRIDAY...
ACTIVE PATTERN CONTINUES AS MODELS PUSH SMALL WAVES OUT ALONG THE
DAMPENING FLOW FROM BROADSCALE/WEAK TROFS TO THE WEST. TIMING WITH
THE ACTIVITY IS STILL A MASSIVE QUESTION MARK...AS NONE OF THESE
SYSTEMS STRIKE WITH A PARTICULARLY ORGANIZED PICTURE OVERALL.
MODERATE TEMPS AND EXTENSIVE POPS DOMINATE THE ALLBLEND AS A WEAK
SHIFT IN THE PATTERN TAKES SHAPE TO AN INCREASINGLY WESTERLY FLOW.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1153 PM CDT FRI APR 27 2012
.DISCUSSION...
ISSUED 836 PM CDT FRI APR 27 2012
LOW PRESSURE OVER KANSAS WILL LIFT NORTHEASTWARD TONIGHT...REACHING
NORTHEAST MISSOURI BY SATURDAY MORNING. VERY DRY AIRMASS PRECEDING
THIS FEATURE WILL KEEP CENTRAL ILLINOIS DRY THROUGH THE EVENING...WITH
SHOWERS SPREADING INTO THE AREA OVERNIGHT. LATEST RADAR
MOSAIC SHOWS SHOWERS/STORMS DEVELOPING IN THE WARM SECTOR OF THE
SYSTEM OVER NORTHWEST MISSOURI...AND THESE ARE EXPECTED TO LIFT/DEVELOP
INTO WEST-CENTRAL ILLINOIS AFTER MIDNIGHT. BASED ON CURRENT
TRAJECTORY AND LATEST HRRR DATA...THINK MAINLY THE N/NW KILX CWA
WILL BE IMPACTED. AS SUCH...HAVE ADJUSTED POPS TO GO LIKELY ALONG
AND NORTHWEST OF A JACKSONVILLE TO DANVILLE LINE...WITH ONLY
CHANCE POPS FURTHER SOUTH AND EAST. GIVEN DRY AIRMASS...CONVECTION
WILL BE WEAKENING AS IT APPROACHES...RESULTING IN MAINLY SHOWERS
WITH PERHAPS A RUMBLE OF THUNDER. UPDATED ZONES HAVE ALREADY BEEN
ISSUED.
&&
.AVIATION...
ISSUED 1153 PM CDT FRI APR 27 2012
NOT A LOT OF CHANGES IN FORECAST TRENDS FOR THE 06Z TAFS EXPECTED.
SOME OF THE PCPN WILL TRY TO TIME WITH THE 2 WAVES OF SHOWERS SEEN
ON RADAR. THESE SUPPORTED BY SPOKES OF UPPER LEVEL VORT WRAPPING
AROUND THE NE VORT MAX. MAIN CONCERN NOW IS POSSIBLE LLWS
OVERNIGHT DUE TO THE PROGGED LOW LEVEL JET FROM THE SOUTHWEST
INTENSIFYING OVER MO-IL AS SURFACE LOW MOVES INTO NORTH MO
OVERNIGHT. STILL LOOKING AT THIS...BUT WILL HAVE TO ADD THIS DUE
TO EXPECTED SIGNIFICANT DEVELOPING SHEAR.
GOETSCH
&&
.PREV DISCUSSION...
ISSUED 200 PM CDT FRI APR 27 2012
WATER VAPOR LOOP SHOWING TWO DISTINCT UPPER WAVES TO OUR WEST.
THE STRONGER OF THE TWO SHORTWAVES WAS LOCATED OVER SOUTHWEST
MONTANA WITH THE SECONDARY WAVE ACRS WESTERN KS...WHICH IS BEING
DRAWN NORTHWARD AS IT ENCOUNTERS A BLOCKING RIDGE ACRS THE
NORTHERN PLAINS. FURTHER EAST...A LARGE CANADIAN HIGH WAS ANCHORED
NORTH OF THE GREAT LAKES EARLY THIS AFTERNOON HELPING TO DRAWN
DOWN SOME COOL AND VERY DRY AIR SOUTH INTO OUR AREA.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
SEVERAL CONCERNS THIS FORECAST PERIOD INCLUDING...TIMING OF RAIN
ACROSS THE FORECAST AREA THIS EVENING AND THEN CONVECTION CHANCES
INCLUDING SEVERE THREAT AROUND THE I-70 CORRIDOR TOMORROW AFTERNOON.
AFTER THAT...A SERIES OF WEATHER SYSTEMS MOVE OUT OF THE SOUTHERN
PLAINS AND INTERACT WITH A FRONTAL BOUNDARY WHICH WILL BE SHIFTING
SLOWLY NORTH AS THE LARGE CANADIAN HIGH FINALLY EDGES OFF TO OUR
EAST. THIS WILL BRING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH EARLY NEXT WEEK.
FORECAST SOUNDINGS SHOWING ONLY A SLOW MOISTENING OF THE LOWER LEVELS
THIS EVENING AS THE SURFACE LOW PRESSURE AREA ASSOCIATED WITH THE KANSAS
UPPER WAVE MOVES INTO NORTHERN MISSOURI BY LATE TONIGHT. IT APPEARS
WE WILL SEE OUR BEST THREAT FOR SHOWERS AND ISOLATED THUNDERSTORMS LATE
THIS EVENING WEST...AND THEN SHIFTING NORTHEAST OVER THE REMAINDER
OF THE AREA LATE TONIGHT...BEFORE EDGING OUT OF OUR AREA BY LATE SATURDAY
MORNING AS THE SURFACE WAVE SHIFTS INTO EAST CENTRAL MO/SOUTHWEST ILLINOIS
BY NOON. LOOKS AS IF THE NAM-WRF HANGS ON TO THE IDEA OF A CLOSED SFC
WAVE TOO LONG BASED ON THE UPPER SYSTEM PULLING WELL OF TO ITS NW DURING
THE MORNING.
LOCAL HI-RES MODELS SUGGEST THE WARM FRONT WILL PUSH TO JUST SOUTH
OF I-70 BY EARLY TOMORROW AFTERNOON WITH STEEP MID LEVEL LAPSE RATES
OF UP TO 8 DEG/C AND MIXED LAYER CAPES OF 1500-2000 J/KG ALONG AND
JUST SOUTH OF THE WARM FRONT. SCATTERED STORMS ARE EXPECTED TO DEVELOP
IN THE 18Z-21Z TIME FRAME JUST EAST OF THE WEAKENING SFC WAVE AND
ALONG/JUST SOUTH OF THE WARM FRONT. AT THIS TIME...IT APPEARS THE PRIMARY
MODE OF CONVECTION TOMORROW AFTERNOON WOULD BE INITIALLY SUPERCELLUAR
WHICH WOULD QUICKLY TRANSLATE MORE INTO A LINEAR MODE BASED ON THE
UNIDIRECTIONAL WINDS FORECAST IN SE IL. PRIMARY THREAT WOULD BE LARGE
HAIL AND DAMAGING WINDS...WITH AN ISOLATED TORNADO POSSIBLE...ESP JUST
EAST OF THE SFC WAVE AND ALONG THE WARM FRONT.
ANY LINGERING CONVECTION SHOULD COME TO AN END BY 00Z ACRS SE IL WITH
THE BOUNDARY GETTING NUDGED BACK SOUTH AGAIN AS THE CANADIAN HIGH
BUILDS BACK INTO THE AREA SATURDAY EVENING. WILL CONTINUE TO HOLD
ON TO CHANCE POPS ACRS SOUTHERN IL AS THE BOUNDARY WILL NOT BE THAT
FAR AWAY. MEANWHILE...FURTHER TO THE NORTHWEST...THE UPPER LOW SHIFTS
SLOWLY NORTH INTO SOUTHERN CANADA AS THE RELENTLESS BLOCK HOLDS FIRM
ACRS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. MODELS BEGIN TO
BUILD THE HEIGHTS ACRS THE AREA IN RESPONSE TO THE RETREATING UPPER
WAVE WHICH SHOULD ALLOW THE LARGE CANADIAN HIGH TO EDGE FURTHER
EAST ON SUNDAY/SUNDAY NIGHT. THE FRONTAL BOUNDARY TO OUR SOUTH WILL
BEGIN TO PUSH BACK NORTH DURING THIS TIME FRAME WITH ALL MODELS
INDICATING WEAK DISTURBANCES MOVING OUT OF THE SOUTHERN PLAINS. ONE
SUCH WAVE WILL PUSH ALONG THE BOUNDARY AND BRING AN INCREASING
THREAT FOR SHOWERS/THUNDERSTORMS LATE SUNDAY INTO A PORTION OF MONDAY
BEFORE SHIFTING OFF TO OUR EAST MONDAY NIGHT.
LONG TERM...TUESDAY THROUGH FRIDAY
A WARMER AND ACTIVE WEATHER PATTERN CONTINUES TO BE DEPICTED ON
MEDIUM RANGE MODELS DURING THIS FORECAST PERIOD...HOWEVER...TIMING
OF INDIVIDUAL SHORTWAVES ACRS THE AREA AS THE PATTERN DEAMPLIFIES
CONTINUES TO BE A CHALLENGE WITH RESPECT TO PRECIP CHANCES EACH DAY.
PATTERN TRANSITIONS INTO MORE OF A ZONAL FLOW EARLY IN THE FORECAST
PERIOD...THEN THE UPPER FLOW SHIFTS TO SOUTHWESTERLY LATE IN THE WEEK
AS A TROF SHIFTS INTO THE WEST COAST. MOST OF OUR AREA WILL BE ALONG
THE SOUTHERN PERIPHERY OF THE STRONGER WINDS ALOFT...WHICH USUALLY
TRANSLATES TO PERIODIC CONVECTION CHANCES THIS TIME OF YEAR...AND
UNFORTUNATELY...THIS IS THE CASE THRU THE EXTENDED PORTION OF THE
FORECAST. ALTHOUGH TEMPERATURES WILL WARM WELL INTO THE 70`S TO
LOWER 80S STARTING TUESDAY...THE PATTERN CONTINUES TO SUPPORT A
LEAST MENTIONABLE POPS IN THE GRIDS EACH DAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1002 AM CDT SAT APR 28 2012
.UPDATE...
AN UPDATED ZFP AND GRIDS WERE SENT WITH SOME MINOR ADJUSTMENTS TO
THE PRECIP WORDING FOR THE REST OF THE MORNING. THE BULK OF THE
MEASURABLE RAIN HAS MOVED OUT OF EAST CENTRAL IOWA SO SCALED BACK
ON THE PRECIP WORDING FOR THE REST OF THE MORNING TO MAINLY PATCHY DRIZZLE.
ALSO ADDED SOME SPRINKLES OVER THE SOUTH HALF OF THE CWFA.
LATEST 88D DATA WAS SHOWING SOME SPOTTY SHRA OVER SOUTHEAST IOWA.
THE SHRA WAS IN AN AREA OF WEAK BUT DEEP FGEN WHICH THE RUC KEEPS
OVER THE SOUTH THROUGH 18Z. THE RUC WAS ALSO SHOWING THAT THE BEST RH
WAS IN THE 700-500MB LAYER WITH A DRY LAYER BELOW...SO -SHRA BASED
THIS LAYER SHOULD AMOUNT TO LITTLE MORE THE SPRINKLES. TEMPERATURES
WERE LEFT UNTOUCHED AT THIS TIME. HIGHS AROUND 60 IN THE SOUTH
SEEMS A BIT OPTIMISTIC...BUT THE CLEARING/WARMER AIR IS WITHIN A
COUNTY OF OUR SOUTHTERN BORDER...CLOSE ENOUGH TO HOLD ON TO THE CURRENT
FORECAST. ALSO THE MID 40S IN THE NORTH THIS AFTERNOON MAY BE ON
THE OPTIMISTIC SIDE WITH A STIFF EAST WIND AND LOW OVERCAST SKIES
THROUGH THE AFTERNOON. DLF
&&
.AVIATION... /ISSUED 706 AM CDT SAT APR 28 2012/
A WEAK LOW PRESSURE SYSTEM PASSING SOUTH OF THE AREA WILL KEEP
WIDESPREAD LOW CLOUDS AND PATCHY LIGHT PRECIPITATION IN PLACE OVER
THE AREA TODAY. IFR CIGS OVER CENTRAL AND WESTERN IA WILL SPREAD
EAST OVER THE CID AND DBQ TERMINALS THIS MORNING AND LINGER THERE
THROUGH MUCH OF THE DAY. THERE WILL ALSO BE PERIODS OF VERY
LIGHT RAIN/DRIZZLE AND FOG THAT WILL REDUCE VISIBILITIES TO 3 TO 5
MILES. CONDITIONS AT BRL AND MLI ARE OPTIMISTICALLY KEPT
MVFR...BUT A PERIOD OF IFR WILL BE POSSIBLE AS WELL. BRISK EAST
WINDS WILL DIMINISH AND LOSE GUSTS BY MID AFTERNOON. MVFR AND
POSSIBLY IFR CIGS WILL REMAIN IN PLACE OVERNIGHT. THERE WILL BE
POTENTIAL FOR SHOWERS TOWARD MORNING AT ESPECIALLY BRL THAT MAY
BE ADDED TO LATER FORECASTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
653 AM EDT SAT APR 28 2012
.Forecast Update...
Issued at 645 AM EDT Sat Apr 28 2012
Band of showers and isolated thunderstorms associated with zone of
isentropic lift over east-central and northern Kentucky continues to
push east and will exit our forecast area in another hour or so.
Meanwhile, additional showers are developing over parts of Illinois
into west-central to southwest Indiana. Most of these should stay
north of our area, but could clip parts of south-central Indiana.
Latest surface warm frontal position is over southwest Kentucky with
a sharp dewpoint change across it (upper 30s and 40s to the north,
and lower 60s to the south of the boundary). The front will continue
to push northeast today.
For this afternoon, 06 UTC model runs and latest HRRR model continue
to support thunderstorm development this afternoon over southern
Indiana and north-central and east-central Kentucky along and near
warm front where best low-level moisture and convergence should be
pooled along. Haved actually increased storm probabilities a bit
this afternoon, especially over east-central Kentucky. Some severe
storms still look like a decent bet with good instability and
low-level lapse rates along with modest shear that should lead to
pulse/multicell storms with hail and possible upgrowth into an MCS
(QLCS) with small scale bowing segments causing potentially damaging
wind gusts in a few spots.
.Short Term (Today through Sunday)...
Issued at 330 AM EDT Sat Apr 28 2012
...Potential for scattered severe thunderstorms this afternoon and
early evening over southern Indiana and northern part of central
Kentucky...
Broad upper low will move into the northern Plains today with
westerly mid-level flow streaking east to the south of the low from
the central U.S. into the Ohio Valley. A warm front at the surface
currently positioned over western Tennessee into Missouri at 07z
will lift northeast today bringing a surge of warmer low-level air
northward across central Kentucky, along with higher surface
dewpoints. The front should reach a line from southern Illinois to
near Louisville to near Lexington around mid afternoon. It will
continue a little farther northeast late this afternoon, but will
then stall given westerly flow aloft and presence of troughing aloft
over the eastern Great Lakes. The front will help focus low-level
moisture convergence and lift in an increasingly unstable air mass
this afternoon. Models suggest a weak shortwave will assist with
convective development this afternoon as well. SPC WRF model showed
convection firing over eastern Missouri and southern Illinois then
tracking east along the warm front into southern Indiana and
north-central and then east-central Kentucky by late afternoon and
early evening.
Model soundings show some elevated instability this morning above
the cooler, more stable boundary layer north of the warm front. This
could lead to scattered showers this morning ver southern Indiana
and parts of the Bluegrass area with some weak isentropic lift. By
this afternoon, with warm frontal passage, low-level lapse rates
will steepen nicely along with some dry air aloft. This is a good
setup for some pulse type severe storms with large hail and local
wind damage, mainly over south-central Indiana and north-central and
eventually east-central Kentucky. Deep-layer shear is modest but
should be enough for possible storm organization, so upscale growth
into a forward propagating convective system with small scale bowing
segments is possible late today as well. South-central Kentucky will
be clearly in the warm sector with less overall forcing and a
slightly more capped air mass. Thus, will forecast only isolated
thunderstorms in this area this afternoon for now.
For tonight, convection will begin to wane with loss of diurnal
heating. Also, the warm front will stall and actually push back
south across central Kentucky bringing cooler, more stable boundary
layer air across southern Indiana and north-central and east-central
Kentucky. There still will remain some elevated instability so can`t
rule out isolated showers/thunderstorms tonight. Low temperatures
will fall into the mid-upper 40s over our northeast forecast area,
with mid-upper 50s over southwest regions south of the front.
For Sunday, the front will be quasi-stationary over central to
south-central Kentucky. Models are tenuous in convective forcing and
axis of moisture. There could be isolated to scattered elevated
showers and storms over southern Indiana and north-central and
east-central Kentucky but difficult to establish trends at this
time. The best location for scattered convection Sunday afternoon
appears to be near the front over central or south-central Kentucky,
if there is enough low-level moisture convergence to overcome the
convective cap during the day. If cells develop near the front
Sunday, isolated strong storms again could occur, but the severe
potential will be lower than later this afternoon over northern
areas. High temperatures Sunday may vary considerably on both sides
of the front, with upper 60s and lower 70s north to the lower to mid
80s south.
.Long Term (Sunday Night through Friday)...
Issued at 335 AM EDT Apr 28 2012
Sunday Night through Tuesday Night...
By Sunday night, both the GFS and Euro solutions suggest that
mid-level ridging will build sharply across the Ohio Valley in
response to two troughs to our NW and to our NE. At the surface, a
warm frontal boundary should be located to our north. The ridging
looks to hold into the day on Monday which should keep the area
fairly dry. Can`t rule out isolated showers or storms Sunday night
and Monday, but feel that the best chances will be to our north
along the aforementioned warm front. A series of weaker mid-level
waves will knock down this mid-level ridge axis and along a frontal
boundary to settle into the area for Tuesday and Tuesday night.
Appears that the best chances for storms will during the afternoon
hours on Tuesday. Looking at model soundings and vertical wind
profiles reveal a strong instability, low shear environment
suggestive of multicellular pulse convection. Convection should
diminish and move off to the east Tuesday night as the mid-level
wave gets shunted off to the east and the mid-level heights quickly
rebuild across the region. Will plan on keeping high chance PoPs in
the forecast for Tuesday afternoon and then decreased them with time
Tuesday night.
Temperatures through the period are expected to remain above normal
for this time of the year. This agrees well with the latest
ensemble anomalies which suggest temps running about 5-8 degrees
above normal. Lows Sunday night will drop into the the lower-mid
50s with highs on Monday warming into the 75-80 degree range. Lows
Monday night will not cool off as much with readings generally in
the lower 60s. Highs on Tuesday will warm back into the 75-80
degree range with lows Tuesday night cooling back into the lower to
middle 60s.
Wednesday through Friday...
For the Wednesday through Friday period, the GFS and Euro suggest
above normal 500 hPa heights across the eastern third of the
country. Both the 28/00Z GFS and Euro deterministic runs develop a
rather large upper ridge across the southeastern US in the Wed/Thu
time frame. Both models generally flatten this ridge toward the end
of the week as a series of weaker disturbances attempts to bring
more of a zonal upper pattern back to the CONUS. The 28/00Z GFS
solutions are more aggressive/progressive with the breakdown of the
ridge. However, this is a typical bias of the GFS in the long term
and am more inclined to go with the slower/conservative Euro which
maintains better continuity with the existing forecast for the
Wed/Thu time frame. Signals within the data are starting to appear
that the ridge will likely break down by the weekend and the Ohio
Valley may get itself into a northwesterly flow type pattern that
could set us up for multiple rounds of convection as we move into
next weekend.
With the ridge axis expected to be closest to us on Wednesday, this
day would appear to be the driest of the period. Isolated-scattered
diurnally driven convection will be possible on Thursday and more
likely as we get into Friday. Given the anticipated setup, a strong
moderation in temperatures is likely from Wednesday into Friday.
Along with the rising temperatures will be a dramatic increase in
dewpoint. In fact, current data signals would suggest downright
warm/muggy conditions as we head toward the end of the week.
Daytime highs will likely run in the 80-85 degree range through the
period with overnight lows only cooling into the low-mid 60s.
&&
.Aviation (12Z TAF Issuance)...
Updated at 650 AM EDT Sat Apr 28 2012
Sky cover has been variable early this morning ranging from cloudy
to mostly clear. A zone of low clouds from 3-4 kft developed over
central Kentucky overnight and is now pushing through east-central
Kentucky, including LEX. These clouds should continue east leaving
only scattered to perhaps broken low clouds (but still VFR) for the
rest of the morning. Winds will continue from the east and southeast
this morning before veering to south and southwest this afternoon as
a warm front moves through. It will move through BWG this morning
and by mid or late afternoon at LEX and SDF, but will stall just
north of SDF. Scattered to numerous thunderstorms still expected by
mid and late afternoon along and near front, potentially affecting
SDF and LEX the most between about 20 UTC and 02 UTC. BWG should see
isolated storms at most. Conditions expected to remain VFR except
temporarily MVFR during storms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........TWF
Short Term.......TWF
Long Term........MJ
Aviation.........TWF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1113 AM EDT SAT APR 28 2012
.SYNOPSIS...
LOW PRESSURE MOVING ALONG A FRONTAL BOUNDARY WILL BRING RAIN BACK
INTO THE AREA FOR THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
THEN BUILD IN FROM THE NORTHWEST AND ALLOW FOR A DRY SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO REDUCE
POPS IN A BREAK IN PRECIP WITH MID-LEVEL DRYING PRIOR TO THE NEXT
SHORT WAVE REACHING THE AREA AROUND 18Z. IN ADDITION, MENTION OF
ISOLATED FLURRIES HAS BEEN FOR THE PITTSBURGH METRO AND AREAS
NORTH AND EAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN
A NEARLY ZONAL FLOW. AN INITIAL SHORT WAVE IS PUSHING SOUTHEAST OF
THE AREA AND ASIDE FROM A FEW LOCATIONS REPORTING LIGHT SPRINKLES
AND FLURRIES, REFLECTIVITY INDICATED BY KPBZ HAS BEEN VIRGA WITH
15-20 TD DEPRESSIONS AT THE SURFACE.
AN AREA OF MID-LEVEL DRYING WILL MOVE ACROSS THE AREA, ALLOWING
FOR A BREAK IN PRECIP INTO THE EARLY AFTERNOON. THE NEXT SHORT WAVE,
MOST EVIDENT IN THE 925-750MB LAYER WILL CONTINUE TO RIDE NORTH OF A
FRONTAL BOUNDARY AND BRING SHOWERS TO THE AREA AFTER 18Z. UPSTREAM
NLDN STRIKES, WEAK ELEVATED INSTABILITY WITH THE WAVE AND THE FRONTAL
BOUNDARY CREEPING NORTHWARD INTO NORTH-CENTRAL WV HAVE LED TO THE
ADDITION OF A SCHC OF THUNDER INTO THE EVENING FOR THE FAR SOUTHERN
ZONES.
THERE IS SOME UNCERTAINTY WITH THE TEMP FORECAST THIS AFTERNOON
DEPENDING ON HOW FAR NORTH THE BOUNDARY MAKES IT. FORECAST IS
CLOSEST TO A LAMP/HRRR BLEND, WITH HIGHS RANGING FROM NEAR 60 ACROSS
NORTH-CENTRAL WV TO THE MID 40S NORTH OF PITTSBURGH.
MODELS DO DIFFER SOMEWHAT TONIGHT WITH PLACEMENT OF FRONT AS IT
PUSHES BACK SOUTH BEHIND SHORTWAVE. BLEND SOLUTION LEAVES CHANCE
POPS ACROSS THE SOUTHEAST RIDGES UNTIL LATE NIGHT WITH REMAINDER OF
REGION DRYING OUT. WITH CLEARING SKIES AND COLD ADVECTION ANOTHER
FREEZE IS PROBABLE, ESPECIALLY ACROSS THE NORTHERN AREAS AND THUS A
FREEZE WATCH REMAINS IN EFFECT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
THE FRONTAL BOUNDARY WILL RETREAT SOUTHWARD ON SUNDAY AS HIGH
PRESSURE BUILDS IN FROM THE UPPER GREAT LAKES. THIS WILL ALLOW FOR
A DRY FORECAST SUNDAY THROUGH MUCH OF THE DAY MONDAY. THAT SAME
BOUNDARY WILL BEGIN TO LIFT BACK NORTHWARD INTO THE AREA AS A WARM
FRONT LATE ON MONDAY, RETURNING THE CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EVENING AS SURFACE-BASED INSTABILITY
INCREASES. THE CHANCE OF THUNDERSTORMS WILL CONTINUE INTO TUESDAY
NIGHT WITH WARM AIR ADVECTION ONGOING. TEMPERATURES WILL BE
PROGRESSIVELY WARMER EACH DAY, WARMING FROM AROUND 5 DEGREES BELOW
NORMAL ON SUNDAY TO 5-10 DEGREES ABOVE NORMAL BY TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
MODELS CONTINUE TO INDICATE EVOLUTION OF A FLAT RIDGE UPPER FLOW
PATTERN OVER THE ERN CONUS AS TROUGH CROSSES THE WEST ON WEDNESDAY.
TEMPERATURE MODERATION MAY THUS BE ANTICIPATED IN THE WARM ADVECTION
REGIME IN ADVANCE OF THAT SYSTEM...PERHAPS TO AS MUCH AS 10
DEGREES ABOVE THE SEASONAL NORMALS.
PRECIPITATION POTENTIAL WILL INCREASE ON THURSDAY...AND CONT INTO
FRIDAY AS THAT TROUGH IS PROGGED TO ADVANCE ACRS THE GREAT LAKES
AND PULL A COLD FRONT TOWARD THE UPPER OHIO REGION. CURRENT TIMING
SUGGESTS THE FRONT WILL BE CLEAR OF THE AREA BY FRIDAY...HENCE POP
NUMBERS AND TEMPERATURES WERE REDUCED FOR THE WEEKEND.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MID LEVEL CLOUDS BLANKETED THE UPR OH REGION THIS MORNING WITH THE
WARM...MOIST ADVECTION IN ADVANCE OF MIDWRN SHORTWAVE. THE DRY
LAYER UNDER 10 KFT IS FORECAST TO BE OVERCOME WITH THE ADVANCE OF
THAT SYSTEM AND AREAS OF MVFR ARE ANTICIPATED BY EVE...ESPECIALLY
OVR SOUTHERN TERMINALS AS WARM FRONT LIFTS TOWARD THOSE PORTS.
CONDITION DEGRADATION WL BE BRIEF THOUGH AS DRY HIGH PRES IS
PROJECTED TO QUICKLY REBUILD OVR THE REGION ON SUNDAY.
.OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SURFACE RIDGE SHOULD CONT TO PROVIDE VFR CONDITIONS INTO MONDAY.
RESTRICTIONS ARE POSSIBLE AGAIN LATE MONDAY...AND INTO WEDNESDAY AS
LOW PRES IS FORECAST TO APPROACH AND CROSS THE UPPER OHIO VALLEY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FREEZE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
OHZ041.
PA...FREEZE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
PAZ007>009-013>016-020-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
644 AM CDT SAT APR 28 2012
.UPDATE...
UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES SHOW AN
AMPLIFIED AND VISUALLY CONVOLUTED PATTERN ACROSS THE CONTINENT AT
THE CURRENT TIME. A CUTOFF UPPER LOW CIRCULATING OVER THE NORTHERN
ROCKIES IS WORKING TO EJECT A SHORTWAVE NORTH INTO SOUTHERN
MINNESOTA... WHICH IS HELPING TO PRODUCE THE BAND OF SHRA ACROSS
THE SOUTHERN PART OF THE FORECAST AREA AT THE CURRENT TIME.
HOWEVER... THIS FEATURE IS RUNNING INTO THE UPPER RIDGE WHICH
EXTENDS FROM CENTRAL SASKATCHEWAN SOUTHEAST THROUGH WISCONSIN...
WHICH IS SHEARING IT OUT WITH TIME AND WORKING TO DIMINISH THE
PCPN AS IT WORKS NORTHWARD. A SECONDARY SURGE OF PCPN WITH THE
UPPER TROUGH TO OUR SOUTH... COINCIDENT WITH BETTER MID-LEVEL
INSTABILITY... IS IN IOWA AND IS ALSO WORKING NORTHWARD WITH TIME.
THE LATEST HRRR AND HIGH RESOLUTION WINDOW RUNS SEEM TO HAVE A
DECENT HANDLE ON ALL OF THIS ACTIVITY... AND SUGGEST IT SHOULD
CONTINUE TO WORK UP INTO THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON... WITH ITS NORTHERN EDGE HAVING A TOUGH TIME MAKING IT
INTO THE NORTH CENTRAL AND NORTHEAST PORTION OF THE AREA GIVEN DRY
LOW LEVEL AIR BACK-FEEDING INTO THE REGION FROM THE SURFACE HIGH
POSITIONED TO OUR EAST. AS FAR AS THE LARGE SCALE PATTERN GOES...
OVERALL IT LOOKS TO DE-AMPLIFY AS WE HEAD INTO THE EARLY PART OF
NEXT WEEK... AS THE UPPER LOW TO OUR WEST SLIDES NORTH INTO CANADA
BY MONDAY AND SOMEWHAT ZONAL FLOW ESTABLISHES ITSELF OVER THE
NORTHERN TIER OF THE CONUS. HOWEVER... THE MEDIUM RANGE GUIDANCE
SUGGESTS SOME TROUGHING DEVELOPING TO OUR WEST BY MIDWEEK WHICH
WILL BRING SOME MORE ACTIVE WEATHER BACK INTO THE AREA BY MIDWEEK
INTO THE LATTER HALF OF THE WEEK. ON THE WHOLE... THE WEATHER WILL
BE SOMEWHAT UNSETTLED THROUGH THE UPCOMING WEEK... BUT AT THE
CURRENT TIME THE ONLY SYSTEM OF ANY PARTICULAR SIGNIFICANCE MAY BE
THE MIDWEEK FEATURE... WHICH COULD HAVE SOME INSTABILITY WITH
WHICH TO WORK AS IT MOVES ACROSS THE AREA ON WEDNESDAY.
AS ALLUDED TO EARLIER... EXPECT TO SEE WIDESPREAD SHRA ACTIVITY
THIS MORNING AS SOME ISENTROPIC UPGLIDE WORKS TO SUSTAIN THE
ACTIVITY CURRENTLY MOVING IN FROM OUR SOUTH EVEN THOUGH THE UPPER
SUPPORT AND DPVA WILL BE FADING WITH TIME AS THE SHORTWAVE
CONTINUES TO SHEAR OUT. LOWEST CHANCES FOR MEASURABLE PCPN WILL BE
OVER THE NORTHEAST CWFA. THE SOUTHEAST CWFA COULD SEE SOME
THUNDER... BUT AT THIS POINT FORECAST 850-500MB DIFFERENTIAL
THETA-E VALUES FROM THE NAM AND GFS SUGGEST LEAVING THAT MENTION
OUT OF THE FORECAST. CURRENT TEMPERATURES ACROSS THE AREA... ALONG
WITH THE 00Z KMPX SOUNDING AND FORECAST SOUNDINGS FROM THE RUC...
SUGGEST IT WILL BE VERY DIFFICULT TO GET ANY SNOWFLAKES FROM THIS
ACTIVITY TODAY. NOT ONLY ARE TEMPERATURES IN THE BOTTOM THOUSAND
OR SO FEET QUITE WARM... BUT AN ELEVATED WARM LAYER IS STILL NOT
COMPLETELY VANQUISHED... AND THUS FAR THERE IS MINIMAL EVIDENCE
SUGGESTING THAT WILL OCCUR. SO... REMOVED ANY MENTION OF SNOW FROM
THE FORECAST FOR TODAY. SHOULD A SUFFICIENTLY HEAVY SHRA OCCUR IT
ISN/T OUT OF THE QUESTION THAT A FEW FLAKES COULD FIND THEIR WAY
TO THE GROUND... BUT ANY SUCH OCCURRENCE WOULD BE ISOLATED AND OF
NO IMPACT SINCE IT WOULD BE SHORT-LIVED AND NON-ACCUMULATING.
LINGERED SOME LOW CHANCE POPS INTO TONIGHT AS THE MID-LEVEL
BAROCLINIC ZONE AND DEEPER MOISTURE WASHES OUT OVER THE AREA. WE
SHOULD FIND OURSELVES SUFFICIENTLY DRY ON SUNDAY AS SOME MODEST
RIDGING SURFACE AND ALOFT BECOMES ESTABLISHED OVER THE AREA... SO
EXCLUDED POPS FROM THE SUNDAY FORECAST. HOWEVER... BY SUNDAY NIGHT
WE COULD SEE SOME LIGHT PCPN WORK ACROSS THE REGION AS THE UPPER
LOW CURRENTLY TO OUR WEST WORKS INTO SOUTHERN CANADA AND HELPS
DRAG A MID-LEVEL TROUGH THROUGH THE STATE ALONG WITH A WEAK
SURFACE TROUGH. THE BEST CHANCES FOR PCPN LOOK TO BE CLOSER TO THE
MAIN UPPER SYSTEM TO OUR NORTH AND CLOSER TO THE BETTER
INSTABILITY AND LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH AND
SOUTHEAST. HOWEVER... GIVEN SUFFICIENT DEEP LAYER MOISTURE AND
SOME WEAK FORCING... LOW POPS SEEM WARRANTED FOR MUCH OF THE AREA
SUNDAY NIGHT INTO MONDAY.
MADE MINIMAL CHANGES TO THE GOING FORECAST FROM MONDAY NIGHT
THROUGH FRIDAY... MEANING THERE CONTINUES TO BE A MENTION OF PCPN
EACH DAY. BY NO MEANS DOES THE ENTIRE PERIOD LOOK LIKE A
WASHOUT... BUT THERE IS SUFFICIENT SPREAD MODEL SOLUTIONS BOTH
WITH RESPECT TO TIMING AND AMPLITUDE OF FEATURES TO INCLUDE PCPN
CHANCES EACH DAY. AT THIS POINT... THE BEST CHANCE FOR WIDESPREAD
PCPN LOOKS TO BE TUESDAY NIGHT AND WEDNESDAY AS WE INITIALLY SEE
SOME HEALTHY RETURN FLOW AND WARM AIR ADVECTION... FOLLOWED BY THE
PASSAGE OF A SURFACE LOW AND ATTENDANT SHARP COLD FRONT THROUGH
THE REGION. AFTER THIS SYSTEM MOVES THROUGH... WE LOOK TO MAINTAIN
A BAROCLINIC ZONE NEARBY FOR THE NEXT FEW DAYS AS A FEW SUCCESSIVE
SHORTWAVES MIGRATE THROUGH ON FAIRLY QUICKLY WESTERLY MID-UPPER
LEVEL FLOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
AREA OF LOW PRES CENTERED OVER SW IA/NW MO WILL CONTINUE TO SHIFT
E THROUGH THE DAY TDA. DEEPER MOISTURE WITH THIS SYSTEM WILL MAKE
FOR BANDS OF LGT/MOD RAIN TO SPREAD N INTO SRN AND CENTRAL MN AND
SW WI. MAINLY THE MN TAF SITES...PARTICULARLY KRWF...WILL BE MOST
SUSCEPTIBLE TO DROPPING INTO MVFR DUE TO DEGRADED VSBY WITH
HEAVIER RAIN. AS THE RAIN GRADUALLY ENDS THIS AFTN...LOWER CIGS
WILL SETTLE IN. THE STRONGER E-SE WINDS THROUGH THE AFTN WILL
PREVENT CIGS FROM DROPPING ANY LOWER THAN MVFR. HOWEVER...LATER
THIS EVE INTO THE OVERNIGHT HOURS...AS WINDS DROP TO AOB 10 KT...
CIGS LOOK LIKELY TO DROP INTO IFR RANGE FOR SEVERAL HOURS BEFORE
IMPROVING AFTER DAYBREAK SUNDAY.
MSP...VFR TO START WITH SPRINKLES/-SHRA OVER THE AREA BUT HEAVIER
AND STEADIER RAINS WILL GRADUALLY MOVE OVER THE FIELD BY LATE
MORNING...DROPPING VSBY INTO MVFR RANGE FOR AT LEAST A COUPLE OF
HOURS. CIGS DURING THE RAIN WILL REMAIN AT VFR...ESPECIALLY WITH
THE STRONGER SE WINDS FOR MUCH OF THE DAY. ONCE THE RAIN ENDS...
LOWER CEILINGS WILL SETTLE IN...INCLUDING CEILINGS THAT HIT THE
1800 FT THRESHOLD BY THIS EVENING. AS WINDS DROP OFF...WILL LOOK
FOR CEILINGS TO CONTINUE TO LOWER AND AM EXPECTING CIGS TO HIT IFR
RANGE DURING THE OVERNIGHT HOURS TONIGHT. CONDITIONS SHOULD
IMPROVE AFTER DAYBREAK TMRW.
OUTLOOK...
SUN...VFR CONDITIONS WITH MIDLVL CEILINGS UNDER HIGH PRESSURE.
MON-WED...SEVERAL FRONTAL SYSTEMS TO PUSH THROUGH THE REGION...
RESULTING IN PERIODS OF SHWRS/TSTMS. MVFR TO IFR CONDS POSSIBLE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1120 AM EDT SAT APR 28 2012
.SYNOPSIS...
A SURFACE FRONT ACROSS NORTHEAST GEORGIA AND THE UPSTATE OF SOUTH
CAROLINA THIS MORNING SHOULD LIFT NORTH TODAY AS A WARM FRONT...BUT
WILL RETURN BACK TO THE SOUTHWEST LATE ON SUNDAY. ON MONDAY...HIGH
PRESSURE TO THE NORTHEAST WILL AFFECT THE REGION WITH COOLER
TEMPERATURES. THE HIGH WILL MOVE OFF THE EAST COAST ON TUESDAY...
ALLOWING A RETURN OF WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1030 AM... CLOUDS NORTH OF SURFACE BOUNDARY EAST OF MOUNTAINS
WILL CONTINUE INTO THE AFTERNOON... BUT EROSION IS ALREADY OCCURRING
AROUND THE WESTERN AND SOUTHWESTERN PERIPHERY OF THE CWA AND IN THE
FOOTHILLS. MOIST LOW-LEVEL AIR HAVING A HARD PENETRATING TOO FAR WEST ACROSS
THE MOUNTAINS... WHICH IS TYPICAL... SO THAT PART OF CWA WILL
EXPERIENCE A FAIR AMOUNT OF SUN UNTIL CONVECTIVE CLOUDS FILL IN SOME
OF THE GAPS. THE MODELS ARE NEARLY UNANIMOUS IN THEIR AGREEMENT
REGARDING A GRADUAL NORTHWARD MOVEMENT OF THE SURFACE BOUNDARY
ACROSS THE FORECAST AREA THIS AFTERNOON AND EVENING. AS THAT
OCCURS... THE WEAK CAD-LIKE RIDGE OF HIGH PRESSURE EAST OF THE
MOUNTAINS WILL RECEDE... BUT APPEARS THAT QUITE A BIT OF LOW-LEVEL
MOISTURE WILL REMAIN BEHIND. RUC INDICATES THAT SOME MODEST CAPE...
500+ J/KG... WILL EXIST THIS AFTERNOON NEAR BOUNDARY OVER SOUTHERN
PORTION OF CWA. MODEL PROFILES SHOW THAT A FAIRLY WARM LAYER WOULD
HAVE TO BE OVERCOME TO RELEASE THE CAPE... SO DOES NOT APPEAR LIKELY
THAT CONVECTIVE PRECIPITATION WILL DEVELOP THERE. A SLIGHTLY BETTER
CHANCE EXISTS OVER THE MOUNTAINS WHERE HIGHER CAPE CONSISTING OF
INCREASINGLY UNSTABLE LOW AND MID-LEVEL LAPSE RATES WILL SPREAD OVER
THOSE ZONES FROM THE SOUTHWEST BY LATE AFTERNOON. HEATING OVER THE
HIGHER TERRAIN COULD PROMOTE DEVELOPMENT OF WIDELY SCATTERED SHOWERS
OR THUNDERSTORMS.
PREVIOUS DISCUSSION...
AT 320 AM...STATIONARY FRONT OVER THE AREA IS KEEPING TD/S HIGH
WHILE THE MID AND UPPER LEVELS SLOWLY BEGIN TO BECOME FREE OF DEBRIS
CLOUDINESS. DENSE FG IS SETTING UP ACROSS THE WRN UPSTATE AND NE
GA...HOWEVER VISIBILITY IS GOING BACK AND FORTH BTW 1/4SM RANGE AND
BTW 1SM-2SM. ENOUGH VARIABILITY AND NOT WIDESPREAD ENOUGH TO ISSUE A
DFA. OVER NEAR CLT AND THE NW PIEDMONT...LLVL STCU IS FORMING ALONG
A WEAK WEDGE FRONT. EXPECT THESE CLOUDS TO PERSIST THROUGH ABOUT MID
DAY...PERHAPS A BIT LONGER AS H85 WARM FRONT ADVANCES NORTH OVER THE
STRENGTHENING. NOT SEEING ENOUGH DEPTH OF MOISTURE OR ELEVATED
INSTABILITY TO INCLUDE PRECIPITATION. CLOUDS WILL BE THE MAIN WORRY
AS FAR AS MAX TEMPS GO. RIGHT NOW A DECENT TEMP GRADIENT IS
ADVERTISED N/S. MAXES SHOULD BE IN THE M80S SOUTH WHILE THE NRN
PIEDMONT SHOULD ONLY GET INTO THE MID TO UPPER 60S. ISOL CONVECTION
IS POSSIBLE ACROSS THE NC MTNS THIS AFTERNOON...AS LLVL WINDS SHIFT
S/LY AND SUPPLY MECHANICAL LIFT TO A MODESTLY UNSTABLE ENVIRONMENT.
MAXES IN THE MTN VALLEYS WILL BE IN M70S.
NO GOOD CHANCE PRECIP OVERNIGHT AS WEDGE DISSIPATES AND SHIFTS EAST.
ALSO THE FRONTAL BOUNDARY WILL BE LOCATED OVER SRN VA. A GOOD AMOUNT
OF CLEARING IS ANTICIPATED OVERNIGHT...HOWEVER THE H100-H85 LAYER
MOISTURE REMAINS MOIST ENOUGH TO SUPPORT SCT STCU ACROSS AT LEAST
THE NRN ZONES. THIS COMBINED WITH LLVL WAA WILL KEEP MIN TEMPS A
COUPLE CATS ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE SHORT RANGE PART OF THE FORECAST STILL
LOOKS LIKE IT WILL BE DOMINATED BY LOW LEVEL FORCING AND MESOSCALE
PROCESSES. AN UPPER ANTICYCLONE WILL REMAIN IN PLACE OVER THE DEEP
SOUTH WITH AN UPPER RIDGE AMPLIFYING OVERHEAD ON SUNDAY AND SUNDAY
NIGHT. ALTHO THE RIDGE FLATTENS SOMEWHAT LATE MONDAY AND MONDAY
NIGHT...ALL THE SHORT WAVES AND UPPER FORCING REMAINS SHUNTED TO THE
NORTH OF THE REGION. THE LOW LEVEL FORCING IS STILL EXPECTED TO COME
IN THE FORM OF A BACK DOOR COLD FRONT THAT WILL MOVE INTO THE WRN
PIEDMONT AND NC FOOTHILLS ON SUNDAY AFTERNOON. THE TIMING IS
QUESTIONABLE...WITH THE NAM BEING A BIT FASTER TO ESTABLISH THE
MOIST E/NE FLOW. THE FORECAST FAVORS THE GFS A BIT MORE THAN THE NAM
IN THAT PRECIP CHANCES DO NOT CLIMB INTO THE CHANCE RANGE UNTIL THE
EARLY EVENING OVER THE NW PIEDMONT. HIGH TEMPS WERE NUDGED TOWARD A
GUIDANCE BLEND. THE FRONT SHOULD CONTINUE TO PUSH SW ACROSS THE AREA
EAST OF THE MTNS SUNDAY NIGHT. CONVERGENCE ALONG THE BOUNDARY AND
EASTERLY UPSLOPE SUGGEST KEEPING PRECIP IN THE FORECAST OVERNIGHT...
WITH THE HIGHEST CHANCES NEAR THE BLUE RIDGE. ON MONDAY...THE
SITUATION LOOKS WEDGE LIKE WITH A PIECE OF THE SURFACE HIGH BROKEN
OFF NEAR THE MID ATLANTIC COAST. IN THESE SITUATIONS...THE NAM SEEMS
TO HAVE A BETTER HANDLE ON KEEPING THE COLD AIR DAMMING IN PLACE
WHILE THE GFS IS TOO QUICK TO DESTROY IT. CLOUDINESS AND LIGHT
PRECIP SHOULD BE EXPECTED IN THE MORNING...WITH LITTLE IMPROVEMENT
OVER THE USUAL DAMMING LOCATIONS UNTIL MAYBE VERY LATE IN THE DAY.
SOME LOCATIONS WILL NOT MAKE IT OUT OF THE 60S. WILL NOT MAKE ANY
BIG CHANGES TO HIGH TEMPS...BUT SEE WHERE THEY COULD BE A CATEGORY
TOO HIGH IF PRECIP DEVELOPS TO A GREATER EXTENT THAN EXPECTED. LIGHT
PRECIP MAY CONTINUE NEAR THE BLUE RIDGE MONDAY NIGHT WITH THE LOW
LEVEL UPGLIDE...AND TEMPS SHOULD REMAIN MILD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE MEDIUM RANGE LOOKS FAIRLY UNEVENTFUL
WITH FLAT UPPER RIDGING IN PLACE THROUGH MOST OF THE PERIOD...AND
SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. AS A RESULT...THE
MODELS LOOK ALMOST SUMMERLIKE...AND FAVOR MAINLY DIURNAL LOW END
CHANCES OF PRECIP THAT FAVOR THE MTNS. DO NOT SEE MUCH OF A REASON
TO MAKE MANY CHANGES TO THE ONGOING FORECAST...UNTIL LATE IN THE
PERIOD. THE LATEST GFS SHOWS A SHORT WAVE MOVING THROUGH ON FRIDAY
AFTERNOON. WHILE THE TIMING IS UNCERTAIN...BOTH MODELS DROP THE NEXT
FRONT DOWN FROM THE NORTH IN THE AFTERNOON...SO PRECIP CHANCES WILL
PROBABLY BE A BIT BETTER THEN COMPARED TO MID WEEK. WITH THAT IN
MIND...THE FORECAST WILL BE BUMPED UP A BIT.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...MVFR STRATUS AROUND 2KT FT EXPECTED TO CONTINUE UNTIL
APPROXIMATELY 20Z THEN LIFT TO ONLY 3-4K FT. VISIBILITY
UNRESTRICTED. NORTH TO NORTHEAST SURFACE WIND 5 TO 10 KT.
ELSEWHERE...MVFR STRATUS AND STRATOCUMULUS WILL PERSIST INTO THE
AFTERNOON EXCEPT AT KAVL WHERE SCATTERED TO BROKEN CLOUDS NEAR 4K FT
WILL EXIST. BY 20Z EXPECT CLOUD BASES TO LIFT TO 3-4K FT. VISIBILITY
UNRESTRICTED. ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE OVER HIGHER
TERRAIN NEAR KAVL AFTER 18Z.
OUTLOOK...ANOTHER WEAK COLD FRONT WILL DROP INTO THE AREA BY
SUNDAY...ENHANCING SHOWER/TS CHANCES ONCE AGAIN. THE FRONT WILL
REMAIN IN THE VICINITY OF THE AREA THROUGH THE FIRST PART OF THE NEW
WORK WEEK...RESULTING IN CONTINUATION OF UNSETTLED WEATHER/PM
SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS.
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...LGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1034 AM EDT SAT APR 28 2012
.SYNOPSIS...
A SURFACE FRONT ACROSS NORTHEAST GEORGIA AND THE UPSTATE OF SOUTH
CAROLINA THIS MORNING SHOULD LIFT NORTH TODAY AS A WARM FRONT...BUT
WILL RETURN BACK TO THE SOUTHWEST LATE ON SUNDAY. ON MONDAY...HIGH
PRESSURE TO THE NORTHEAST WILL AFFECT THE REGION WITH COOLER
TEMPERATURES. THE HIGH WILL MOVE OFF THE EAST COAST ON TUESDAY...
ALLOWING A RETURN OF WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1030 AM... CLOUDS NORTH OF SURFACE BOUNDARY EAST OF MOUNTAINS
WILL CONTINUE INTO THE AFTERNOON... BUT EROSION IS ALREADY OCCURRING
AROUND THE WESTERN AND SOUTHWESTERN PERIPHERY OF THE CWA AND IN THE
FOOTHILLS. MOIST LOW-LEVEL AIR HAVING A HARD PENETRATING TOO FAR WEST ACROSS
THE MOUNTAINS... WHICH IS TYPICAL... SO THAT PART OF CWA WILL
EXPERIENCE A FAIR AMOUNT OF SUN UNTIL CONVECTIVE CLOUDS FILL IN SOME
OF THE GAPS. THE MODELS ARE NEARLY UNANIMOUS IN THEIR AGREEMENT
REGARDING A GRADUAL NORTHWARD MOVEMENT OF THE SURFACE BOUNDARY
ACROSS THE FORECAST AREA THIS AFTERNOON AND EVENING. AS THAT
OCCURS... THE WEAK CAD-LIKE RIDGE OF HIGH PRESSURE EAST OF THE
MOUNTAINS WILL RECEDE... BUT APPEARS THAT QUITE A BIT OF LOW-LEVEL
MOISTURE WILL REMAIN BEHIND. RUC INDICATES THAT SOME MODEST CAPE...
500+ J/KG... WILL EXIST THIS AFTERNOON NEAR BOUNDARY OVER SOUTHERN
PORTION OF CWA. MODEL PROFILES SHOW THAT A FAIRLY WARM LAYER WOULD
HAVE TO BE OVERCOME TO RELEASE THE CAPE... SO DOES NOT APPEAR LIKELY
THAT CONVECTIVE PRECIPITATION WILL DEVELOP THERE. A SLIGHTLY BETTER
CHANCE EXISTS OVER THE MOUNTAINS WHERE HIGHER CAPE CONSISTING OF
INCREASINGLY UNSTABLE LOW AND MID-LEVEL LAPSE RATES WILL SPREAD OVER
THOSE ZONES FROM THE SOUTHWEST BY LATE AFTERNOON. HEATING OVER THE
HIGHER TERRAIN COULD PROMOTE DEVELOPMENT OF WIDELY SCATTERED SHOWERS
OR THUNDERSTORMS.
PREVIOUS DISCUSSION...
AT 320 AM...STATIONARY FRONT OVER THE AREA IS KEEPING TD/S HIGH
WHILE THE MID AND UPPER LEVELS SLOWLY BEGIN TO BECOME FREE OF DEBRIS
CLOUDINESS. DENSE FG IS SETTING UP ACROSS THE WRN UPSTATE AND NE
GA...HOWEVER VISIBILITY IS GOING BACK AND FORTH BTW 1/4SM RANGE AND
BTW 1SM-2SM. ENOUGH VARIABILITY AND NOT WIDESPREAD ENOUGH TO ISSUE A
DFA. OVER NEAR CLT AND THE NW PIEDMONT...LLVL STCU IS FORMING ALONG
A WEAK WEDGE FRONT. EXPECT THESE CLOUDS TO PERSIST THROUGH ABOUT MID
DAY...PERHAPS A BIT LONGER AS H85 WARM FRONT ADVANCES NORTH OVER THE
STRENGTHENING. NOT SEEING ENOUGH DEPTH OF MOISTURE OR ELEVATED
INSTABILITY TO INCLUDE PRECIPITATION. CLOUDS WILL BE THE MAIN WORRY
AS FAR AS MAX TEMPS GO. RIGHT NOW A DECENT TEMP GRADIENT IS
ADVERTISED N/S. MAXES SHOULD BE IN THE M80S SOUTH WHILE THE NRN
PIEDMONT SHOULD ONLY GET INTO THE MID TO UPPER 60S. ISOL CONVECTION
IS POSSIBLE ACROSS THE NC MTNS THIS AFTERNOON...AS LLVL WINDS SHIFT
S/LY AND SUPPLY MECHANICAL LIFT TO A MODESTLY UNSTABLE ENVIRONMENT.
MAXES IN THE MTN VALLEYS WILL BE IN M70S.
NO GOOD CHANCE PRECIP OVERNIGHT AS WEDGE DISSIPATES AND SHIFTS EAST.
ALSO THE FRONTAL BOUNDARY WILL BE LOCATED OVER SRN VA. A GOOD AMOUNT
OF CLEARING IS ANTICIPATED OVERNIGHT...HOWEVER THE H100-H85 LAYER
MOISTURE REMAINS MOIST ENOUGH TO SUPPORT SCT STCU ACROSS AT LEAST
THE NRN ZONES. THIS COMBINED WITH LLVL WAA WILL KEEP MIN TEMPS A
COUPLE CATS ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE SHORT RANGE PART OF THE FORECAST STILL
LOOKS LIKE IT WILL BE DOMINATED BY LOW LEVEL FORCING AND MESOSCALE
PROCESSES. AN UPPER ANTICYCLONE WILL REMAIN IN PLACE OVER THE DEEP
SOUTH WITH AN UPPER RIDGE AMPLIFYING OVERHEAD ON SUNDAY AND SUNDAY
NIGHT. ALTHO THE RIDGE FLATTENS SOMEWHAT LATE MONDAY AND MONDAY
NIGHT...ALL THE SHORT WAVES AND UPPER FORCING REMAINS SHUNTED TO THE
NORTH OF THE REGION. THE LOW LEVEL FORCING IS STILL EXPECTED TO COME
IN THE FORM OF A BACK DOOR COLD FRONT THAT WILL MOVE INTO THE WRN
PIEDMONT AND NC FOOTHILLS ON SUNDAY AFTERNOON. THE TIMING IS
QUESTIONABLE...WITH THE NAM BEING A BIT FASTER TO ESTABLISH THE
MOIST E/NE FLOW. THE FORECAST FAVORS THE GFS A BIT MORE THAN THE NAM
IN THAT PRECIP CHANCES DO NOT CLIMB INTO THE CHANCE RANGE UNTIL THE
EARLY EVENING OVER THE NW PIEDMONT. HIGH TEMPS WERE NUDGED TOWARD A
GUIDANCE BLEND. THE FRONT SHOULD CONTINUE TO PUSH SW ACROSS THE AREA
EAST OF THE MTNS SUNDAY NIGHT. CONVERGENCE ALONG THE BOUNDARY AND
EASTERLY UPSLOPE SUGGEST KEEPING PRECIP IN THE FORECAST OVERNIGHT...
WITH THE HIGHEST CHANCES NEAR THE BLUE RIDGE. ON MONDAY...THE
SITUATION LOOKS WEDGE LIKE WITH A PIECE OF THE SURFACE HIGH BROKEN
OFF NEAR THE MID ATLANTIC COAST. IN THESE SITUATIONS...THE NAM SEEMS
TO HAVE A BETTER HANDLE ON KEEPING THE COLD AIR DAMMING IN PLACE
WHILE THE GFS IS TOO QUICK TO DESTROY IT. CLOUDINESS AND LIGHT
PRECIP SHOULD BE EXPECTED IN THE MORNING...WITH LITTLE IMPROVEMENT
OVER THE USUAL DAMMING LOCATIONS UNTIL MAYBE VERY LATE IN THE DAY.
SOME LOCATIONS WILL NOT MAKE IT OUT OF THE 60S. WILL NOT MAKE ANY
BIG CHANGES TO HIGH TEMPS...BUT SEE WHERE THEY COULD BE A CATEGORY
TOO HIGH IF PRECIP DEVELOPS TO A GREATER EXTENT THAN EXPECTED. LIGHT
PRECIP MAY CONTINUE NEAR THE BLUE RIDGE MONDAY NIGHT WITH THE LOW
LEVEL UPGLIDE...AND TEMPS SHOULD REMAIN MILD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE MEDIUM RANGE LOOKS FAIRLY UNEVENTFUL
WITH FLAT UPPER RIDGING IN PLACE THROUGH MOST OF THE PERIOD...AND
SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. AS A RESULT...THE
MODELS LOOK ALMOST SUMMERLIKE...AND FAVOR MAINLY DIURNAL LOW END
CHANCES OF PRECIP THAT FAVOR THE MTNS. DO NOT SEE MUCH OF A REASON
TO MAKE MANY CHANGES TO THE ONGOING FORECAST...UNTIL LATE IN THE
PERIOD. THE LATEST GFS SHOWS A SHORT WAVE MOVING THROUGH ON FRIDAY
AFTERNOON. WHILE THE TIMING IS UNCERTAIN...BOTH MODELS DROP THE NEXT
FRONT DOWN FROM THE NORTH IN THE AFTERNOON...SO PRECIP CHANCES WILL
PROBABLY BE A BIT BETTER THEN COMPARED TO MID WEEK. WITH THAT IN
MIND...THE FORECAST WILL BE BUMPED UP A BIT.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...MVFR STRATUS AROUND 2KT FT EXPECTED TO CONTINUE UNTIL
APPROXIMATELY 20Z THEN LIFT TO ONLY 3-4K FT. AROUND 00Z CEILING
AOA 10K FT WILL BECOME SCATTERED. VISIBILITY UNRESTRICTED. NORTH
TO NORTHEAST SURFACE WIND 5 TO 10 KT.
ELSEWHERE...MVFR STRATUS AND STRATOCUMULUS WILL PERSIST INTO THE
AFTERNOON EXCEPT AT KAVL WHERE SCATTERED TO BROKEN CLOUDS NEAR 4K FT
WILL EXIST. BY 20Z EXPECT CLOUD BASES TO LIFT TO 3-4K FT. VISIBILITY
UNRESTRICTED. ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE OVER HIGHER
TERRAIN NEAR KAVL AFTER 18Z.
OUTLOOK...ANOTHER WEAK COLD FRONT WILL DROP INTO THE AREA BY
SUNDAY...ENHANCING SHOWER/TS CHANCES ONCE AGAIN. THE FRONT WILL
REMAIN IN THE VICINITY OF THE AREA THROUGH THE FIRST PART OF THE NEW
WORK WEEK...RESULTING IN CONTINUATION OF UNSETTLED WEATHER/PM
SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS.
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...LGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
207 PM EDT SAT APR 28 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS NORTHERN STREAM FLOW
EXTENDING FROM OVER THE 4-CORNERS REGION EASTWARD TO THE TN/OH
VALLEYS AND THEN OFF THE MID-ATLANTIC SEABOARD. CLOSER TO HOME...OUR
FORECAST AREA IS WEDGED BETWEEN UPPER LEVEL RIDGING ALONG THE
NORTHERN GULF COAST...AND A DISTURBANCE SPINNING OVER THE YUCATAN
CHANNEL/FL STRAITS. WV IMAGERY CONTINUES TO SHOW THAT MID/UPPER
LEVEL MOISTURE IS ADVANCING NORTHWARD AHEAD OF THIS DISTURBANCE AND
RAPIDLY ERODING THE DRY AIR CURRENTLY OVER THE FORECAST AREA. THIS
ADVANCING MOISTURE CAN BE SEEN IN SOME SIGNIFICANT DIFFERENCES
BETWEEN THE 12Z SOUNDING PROFILES FROM TAMPA AND MIAMI. THE KTBW
SOUNDING STILL SHOWED A FAIRLY DRY COLUMN ABOVE THE BOUNDARY LAYER
WITH A PW UNDER 1". THE KMFL SOUNDING ON THE OTHER HAND WAS QUITE
MOIST THROUGH THE COLUMN WITH A PW APPROACHING 2". MODEL GUIDANCE IS
IN GOOD AGREEMENT IN THE CONTINUED EROSION OF THE DRY AIR OVER OUR
HEADS INTO THE EVENING HOURS...AND EXPECT OUR 00Z SOUNDING TO SHOW A
JUMP IN PW.
AT THE SURFACE...RIDGE AXIS EXTENDS FROM OFF THE SOUTHEAST COAST
WESTWARD ALONG THE I-10 CORRIDOR. GRADIENT IS STILL RATHER LIGHT
OVER OUR REGION IN CLOSE PROXIMITY TO THE RIDGE AXIS. THIS LIGHT
GRADIENT HAS ALLOWED THE DEVELOPMENT OF BOTH EAST COAST AND WEST
COAST SEA-BREEZE CIRCULATIONS.
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
REST OF TODAY/THIS EVENING...THE INCREASING DEEP LAYER MOISTURE AND
EVENTUAL SEA-BREEZE COLLISIONS SHOULD BE ENOUGH TO FORCE AT LEAST
ISOLATED/WDLY SCT CONVECTION LATER THIS AFTERNOON INTO THE EVENING
HOURS. IN FACT...ALL THE 12Z HI-RES CONVECTIVE ALLOWING MODELS
CONTINUE TO PRODUCE CONVECTION ALONG THE FL WEST COAST LATER TODAY
WITH THE EVENTUAL APPROACH OF THE EAST COAST SEA-BREEZE. SEEING THE
ORGANIZATION OF THE CU FIELD ALREADY IN PLACE...THIS SCENARIO SEEMS
REASONABLE AND WILL KEEP THE 20-30% POPS IN THE FORECAST FROM
PASCO/HERNANDO COUNTY SOUTHWARD. OVER OUR FAR NORTHERN/NATURE COAST
ZONES...KEPT THE POPS AT A SILENT 10% UNDERNEATH THE MORE PRONOUNCED
SUPPRESSION FROM THE UPPER RIDGE.
TONIGHT...ANY LINGERING EVENING STORMS WILL FADE WITH THE LOSS OF
DIURNAL HEATING AND SEA-BREEZE FOCUS WITHIN A FEW HOURS OF SUNSET.
THE REMAINDER OF THE NIGHT LOOKS QUIET WITH GENERALLY DRY CONDITIONS
AND SEASONABLE TEMPERATURES.
SUNDAY THROUGH MONDAY...
TRICKY AND SOMEWHAT STUBBORN PATTERN WILL PERSIST THROUGH THE PERIOD
WITH STACKED RIDGING HOLDING DOMINANCE OVER THE NORTHERN PORTION OF
THE STATE...AND AN UPPER DISTURBANCE AND ASSOCIATED SURFACE TROUGH
AFFECTING THE SOUTHERN PORTION OF THE PENINSULA. ALTHOUGH THE
STRENGTH OF THE SURFACE TROUGH CROSSING THROUGH THE FLORIDA STRAITS
IS SOMEWHAT IN QUESTION DURING THE PERIOD...THERE IS DECENT MODEL
AGREEMENT THAT THE BEST RAIN CHANCES WILL REMAIN SOUTH OF OUR ZONES.
FORT MYERS REGION IS RIGHT ON THE NORTHERN EDGE OF THE LOW LEVEL
FOCUS...SO HAVE KEPT THOSE FAR SOUTHERN ZONES IN A 20-30% RAIN
CHANCE THROUGH THE PERIOD. MOVING FURTHER NORTH FROM CHARLOTTE AND
LEE COUNTIES...AND IT APPEARS THE CHANCES FOR ANY ORGANIZED SHOWER
ACTIVITY FALLS OFF QUICKLY UNDERNEATH THE UPPER RIDGE. WITH THIS IN
MIND...GIVING THE MAJORITY OF THE FORECAST AREA A DRY FORECAST WITH
NEAR TO ABOVE NORMAL TEMPERATURES.
&&
.LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...
THE PERIOD BEGINS WITH AN UPPER RIDGE OVER THE GULF COAST/SE U.S.
AND A TROUGH SOUTH OF FL...FROM CUBA TO THE BAHAMAS. DURING THE WEEK
THE TROUGH WEAKENS AS IT SLIDES EAST WITH THE RIDGE DOMINATING THE
AREA. BUT BY WEEKS END THE RIDGE BEGINS TO SLIDE BACK WEST AS A LOW
MOVES FROM SE CANADA TO THE ATLANTIC...TROUGHING SOUTHWARD ALONG THE
EASTERN SEABOARD. AT THE SURFACE...HIGH PRESSURE OVER NE U.S.
COASTAL WATERS SLIDES SOUTHEASTWARD OVER THE ATLANTIC...RIDGING WEST
TO THE CENTRAL GULF COAST AS IT DOES. THIS HIGH WILL PROVIDE AN
EASTERLY AND AT TIMES ROBUST LOW LEVEL FLOW THAT BECOMES MORE
SOUTHEASTERLY AND RELAXES TOWARD THE END OF THE WEEK AS THE HIGH
REACHES THE SW ATLANTIC. THE GLOBAL MODELS CONTINUE FAIRLY
CONSISTENT WITH ONLY MINOR LOCATION AND TIMING DIFFERENCES...
ALTHOUGH THE GFS IS MORE AGGRESSIVE WITH MOISTURE AND RAINFALL. FOR
NOW HAVE FAVORED A DRIER SOLUTION WITH ONLY A SLIGHT CHANCE OF
SHOWERS/STORMS. TEMPERATURES WILL RUN ON THE WARM SIDE OF
NORMAL...BY 2 TO 4 DEGREES AT TIMES.
&&
.AVIATION...
A FEW SHOWERS THIS AFTERNOON OVER SOUTHWEST FLORIDA WITH LCL MVFR
CIGS...OTHERWISE VFR CONDITIONS WILL PREVAIL THE REMAINDER OF THE
DAY AND TONIGHT. AREAS OF BKN CIGS 035-045 REST OF THIS AFTERNOON
FROM TPA SOUTH TO RSW. LOW LEVEL CLOUDINESS WILL DECREASE THIS
EVENING WITH LOSS OF DAYTIME HEATING WITH HIGH LEVEL CLOUDINESS
REMAINING THROUGH THE NIGHT MAINLY SOUTH OF SRQ.
&&
.MARINE...
THE FORECAST WATERS WILL REMAIN BETWEEN A RIDGE OF HIGH PRESSURE TO
OUR NORTH...AND A TROUGH OF LOW PRESSURE PASSING TO OUR SOUTH. THE
LOCAL GRADIENT WILL TIGHTEN DURING THE NEXT COUPLE OF DAYS BETWEEN
THESE 2 FEATURES AND LEAD TO INCREASING WINDS AND WAVES INTO THE
EARLY PORTION OF THE WORK WEEK. THE GRADIENT SHOULD ONCE AGAIN RELAX
WEDNESDAY INTO FRIDAY ALLOWING WINDS AND SEAS TO SUBSIDE.
&&
.FIRE WEATHER...
A STEADY SUPPLY OF ATLANTIC MOISTURE WILL HELP KEEP RELATIVE
HUMIDITY VALUES GENERALLY ABOVE CRITICAL LEVELS INTO THE EARLY
PORTION OF THE WORK WEEK. NO RED FLAG CONDITIONS ARE ANTICIPATED
THROUGH MONDAY AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 69 87 70 84 / 15 10 5 15
FMY 68 86 69 85 / 25 35 20 25
GIF 66 89 67 88 / 15 15 5 10
SRQ 68 88 69 86 / 20 15 10 15
BKV 64 89 65 88 / 15 10 5 10
SPG 72 84 71 84 / 20 10 10 15
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...14/MROCZKA
AVIATION/FIRE WEATHER...13/OGLESBY
LONG TERM...09/RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
201 PM EDT SAT APR 28 2012
.AVIATION...
MOISTURE ASSOCIATED WITH A WEAK SURFACE TROUGH CONTINUES TO STREAM
ACROSS SOUTH FLORIDA THIS AFTERNOON. OVER THE NEXT 24 HOURS THE
TROUGH WILL MAKE ITS WAY TO THE WEST KEEPING SHRAS LINGERING OVER
THE AREA. KEPT VCSH MENTION THROUGH THE PERIOD AT ALL SITES.
TSRAS HAVE DIMINISHED CONSIDERABLY OVER THE PAST COUPLE OF HOURS.
HOWEVER...CANNOT RULE OUT AN ISOLATED TSRA FOR THE REMAINDER OF
THE PERIOD BUT LEFT ANY VCTS MENTION OUT FOR NOW. EASTERLY FLOW
WILL INCREASE THROUGH THE PERIOD AND BECOME GUSTY INTO THE EVENING
HOURS.
&&
.PREV DISCUSSION... /ISSUED 1002 AM EDT SAT APR 28 2012/
UPDATE...NOT QUITE SURE WHAT TO DO WITH CURRENT FCST CONSIDERING
HEAVIEST ACTIVITY REMAINING OFFSHORE. RADAR SIGNATURES CURRENTLY
INDICATE A SFC TROUGH MAY BE LOCATED FROM NEAR NASSAU TO HST AND
THEN EXTENDING INTO THE GOMEX. BOTH THE GFS AND ECMWF ARE THE
CLOSEST TO CURRENT TRENDS AND DO KEEP THE HEAVIEST CONVECTION OVER
THE BAHAMAS AND FLORIDA KEYS NEAR AND ALONG THE TROUGH AXIS. THE
GFS, NAM AND RAPID REFRESH ALL SHOW CONVECTIVE DEVELOPMENT OVER
INTERIOR S FL BY 18-19Z AND THEN MOVES TOWARDS THE W CST THROUGH
LATE AFTERNOON WHEREAS THE ECMWF IS MORE OF A BROAD BRUSH APPROACH.
SO BASED ON THE CURRENT TRENDS AND THE MODEL CONSENSUS SOLUTIONS
FOR THE REMAINDER OF THE DAY, WILL LOWER POPS SLIGHTLY FOR THE E
CST AND RAISE SLIGHTLY FOR COASTAL COLLIER.
KOB
PREV DISCUSSION... /ISSUED 638 AM EDT SAT APR 28 2012/
AVIATION...12Z ISSUANCE...LITTLE CHANGE FROM EARLIER DISCUSSION.
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS THE REGION AS A
TROUGH OF LOW PRESSURE FORMS IN THE CARIBBEAN. SCT SHRA AND A FEW
TSRA WILL IMPACT AN AREA BETWEEN KPBI AND KFLL THROUGH 13Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. ANTICIPATED TSRA COVERAGE TOO
LOW TO INCLUDE VCTS ATTM. WHILE CEILINGS AND VISIBILITIES WILL
REMAIN PREVAILING VFR, BRIEF INTERVALS OF MVFR-IFR ARE CERTAINLY
POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST SURFACE WINDS WILL
CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH OCCASIONAL HIGHER
GUSTS.
PREV DISCUSSION... /ISSUED 424 AM EDT SAT APR 28 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH 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.
AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
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 AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 80 73 82 / 50 40 40 40
FORT LAUDERDALE 72 80 72 83 / 60 60 40 40
MIAMI 71 80 72 83 / 60 60 40 40
NAPLES 69 84 69 84 / 30 40 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1229 PM CDT SAT APR 28 2012
.DISCUSSION...
ISSUED 1020 AM CDT SAT APR 28 2012
LATEST SURFACE MAP SHOWED WARM FRONT ROUGHLY ALONG A PITTSFIELD TO
LAWRENCEVILLE LINE. DEWPOINTS OF 55-60F SURGING IN FROM THE
SOUTHWEST BEHIND THE FRONT...WITH FLORA CURRENTLY UP TO 58F. SOME
CLEAR SKIES HAVE OCCURRED SOUTH OF THE FRONT AS WELL...HELPING TO
BOOST MUCAPES TO OVER 1000 J/KG ACCORDING TO LATEST SPC
MESOANALYSIS.
MAIN CONCERN FOR TODAY IS WITH CONVECTION. HIGH-RESOLUTION MODELS
AND 12Z NAM BRING THE FRONT TO NEAR THE I-72 CORRIDOR THIS
AFTERNOON...AS A WEAK SURFACE WAVE RIDES ALONG THE BOUNDARY. MOST
LIKELY LOCATION FOR CONVECTIVE INITIATION SHOULD BE AROUND SAINT
LOUIS...BEFORE FILLING IN SOUTH OF THE BOUNDARY INTO SOUTHEAST
ILLINOIS EARLY THIS AFTERNOON. SOUTHEAST CWA WILL BE WELL INTO THE
WARM SECTOR AS TEMPERATURES RISE INTO THE 70S AND DEWPOINTS REACH
60-65F...HELPING TO DESTABILIZE THINGS FURTHER AS RUC MUCAPES
REACH NEAR 3000 J/KG IN THAT AREA. SPC DAY1 SLIGHT RISK CONTINUES
ALONG AND SOUTH OF I-70.
NORTH OF THE FRONT...MOST PRECIPITATION THIS AFTERNOON SHOULD
MAINLY BE IN THE FORM OF SOME PATCHY DRIZZLE. SOME MODEST
TEMPERATURE RISES ARE EXPECTED...BUT HIGHS IN THE 50S WILL BE
COMMON NORTH OF I-74.
GEELHART
&&
.AVIATION...
ISSUED 1218 PM CDT SAT APR 28 2012
SHOWERS/STORMS HAVE BEGUN DEVELOPING ACROSS WEST CENTRAL ILLINOIS
AT MIDDAY. AWIPS TIME-OF-ARRIVAL TOOL INDICATES THE STORMS BE
NEAR KSPI AROUND 18Z AND KDEC JUST BEFORE 19Z. RADAR LOOPS WOULD
SUGGEST THEY WOULD STAY JUST BARELY SOUTH OF THE AIRPORTS...BUT
WILL MENTION TEMPO GROUPS FOR TSRA THE FIRST COUPLE HOURS TO
ACCOUNT FOR ANY NORTHWARD DEVELOPMENT. WITH WARM FRONTAL BOUNDARY
ROUGHLY ALONG THE KSPI-KCMI CORRIDOR...MOST CONVECTION WILL REMAIN
TO THE SOUTH THIS AFTERNOON.
ANY UPWARD MOVEMENT IN THE CEILING HEIGHTS THIS AFTERNOON IS
LIKELY TO COME BACK DOWN TO MVFR RANGE THIS EVENING...AS AN UPPER
WAVE SENDS SOME PERIODS OF LIGHT RAIN BACK OVER THE TAF SITES
OVERNIGHT INTO SUNDAY.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 313 AM CDT SAT APR 28 2012
RATHER COMPLICATED WEATHER PATTERN ACROSS MUCH OF THE COUNTRY THIS
MORNING. A LARGE STRONG SFC PRESSURE RIDGE FROM THE HUDSON BAY TO
THE MID ATLANTIC STATES BLOCKING THE RAPID ADVANCE OF A LOW MOVING
OUT OF THE PLAINS INTO THE MIDWEST THIS MORNING. DEEP UPPER LOW IN
ERN CANADA SLOWLY MOVING EASTWARD...AND SEVERAL MORE WAVES PROGGED
TO MOVE OUT OF THE WEST OFF OF A LOW IN THE NRN FRONT RANGE OF THE
ROCKIES. MODELS CONTINUE A RATHER WET BIAS THROUGHOUT THE
FORECAST...RESULTING IN MANY OCCURRENCES OF POPS FOR WHAT IS MORE
LIKELY TO BE SOME SHOWERY DAYS...WITH WIDESPREAD PRECIPITATION
SCARCE AT BEST.
SHORT TERM...TODAY THROUGH MONDAY...
MODELS HAVING A HARD TIME WITH THE CURRENT SITUATION AS THE LOW
MOVES NEWD INTO THE GREAT LAKES...WITH THE REMNANT BOUNDARIES LEFT
IN THE REGION AS THE LOW WEAKENS. SEVERAL SHORT WAVES EJECTED
AROUND THE DEEPER SYNOPTIC TROF TO THE WEST KEEPING THE PRECIP IN
THE REGION...INTERACTING WITH THE BOUNDARIES THROUGH THE WEEKEND.
THOUGH THE POPS ARE IN ALMOST EVERY PERIOD...IMPORTANT TO MENTION
THE MORE SHOWERY...AND NOT WIDESPREAD...NOR LONG DURATION
ANTICIPATED WITH THIS PRECIP EVENT. POSSIBILITY REMAINS THAT MUCH
OF THE FORECAST MAY END UP BETWEEN THE BEST PRECIP TO THE NORTH
AND SOUTH. HOWEVER...SOME CONCERN OUT THERE FOR SOME TS/SLIGHT
RISK OF SVR WEATHER IN THE SERN PORTION OF THE CWA THIS
AFTERNOON/EVENING...WITH MAX HEATING AND FRONT INTERACTING WITH
ANY SHORTWAVE MOVING THROUGH. MOSTLY AN ISSUE FOR HAIL/WIND...WITH
A BIT OF AN ISSUE FOR SOME MODERATE DEEP LAYER SHEAR. WET OFF AND
ON THROUGH THE WEEKEND...COOLER TODAY IN THE NORTH...AND
TEMPERATURES MODERATING SOMEWHAT TOMORROW WITH MORE EXTENSIVE
CLOUD COVER...AND THE FRONT JUST TO THE SOUTH POTENTIALLY WITH
RAIN COOLED AIR KEEPING THE WARMTH AT BAY. MONDAY PUSHING THE
FRONT A LITTLE FURTHER NORTH RESULTING IN WARMER TEMPS FOR THE SRN
PORTION OF THE STATE. HOWEVER...CONSIDERING THE UNRELIABILITY OF
THE MODELS OF LATE...HAVE AN ISSUE WITH CALLING THE LOCALE FOR THE
HIGHER POPS ALONG THE BOUNDARY. WILL REFRAIN...KEEP MORE GENERAL
POPS IN...AND ADD DETAIL AS THE MODELS COME INTO AGREEMENT.
LONG TERM...TUESDAY THROUGH FRIDAY...
ACTIVE PATTERN CONTINUES AS MODELS PUSH SMALL WAVES OUT ALONG THE
DAMPENING FLOW FROM BROADSCALE/WEAK TROFS TO THE WEST. TIMING WITH
THE ACTIVITY IS STILL A MASSIVE QUESTION MARK...AS NONE OF THESE
SYSTEMS STRIKE WITH A PARTICULARLY ORGANIZED PICTURE OVERALL.
MODERATE TEMPS AND EXTENSIVE POPS DOMINATE THE ALLBLEND AS A WEAK
SHIFT IN THE PATTERN TAKES SHAPE TO AN INCREASINGLY WESTERLY FLOW.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1215 PM CDT SAT APR 28 2012
.AVIATION...
STORM SYSTEM WILL PUSH EASTWARD WITH DRIER AIR FILTERING IN BEHIND
THE SYSTEM. CURRENTLY MVFR CEILINGS AT KCID...KMLI....AND KBRL WITH
IFR CEILINGS AT KDBQ. CEILINGS ARE EXPECTED TO LIFT THIS AFTERNOON
WITH SOME HEATING...ALTHOUGH CIGS A KDBQ WILL SEE THE LEAST
IMPROVEMENT WITH SURFACE TEMPS NOT EXPECTED TO RISE MUCH.
OCCASIONAL DRIZZLE OR SPRINKLES ARE POSSIBLE AT ALL SITES THIS
AFTERNOON.
CEILINGS WILL LOWER AND THICKEN AGAIN OVERNIGHT FROM SOUTHWEST TO
NORTHEAST BUT REMAIN MVFR AS MOISTURE AHEAD OF ANOTHER STORM SYSTEM
MOVES INTO THE MID MISSISSIPPI VALLEY. INTRODUCED VCSH AT KBRL AS
MODELS HINT THAT SHOWERS MAY MOVE INTO SOUTHEASTERN IOWA BY 18 UTC.
DC/DLF
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT SAT APR 28 2012/
UPDATE...
AN UPDATED ZFP AND GRIDS WERE SENT WITH SOME MINOR ADJUSTMENTS TO
THE PRECIP WORDING FOR THE REST OF THE MORNING. THE BULK OF THE
MEASURABLE RAIN HAS MOVED OUT OF EAST CENTRAL IOWA SO SCALED BACK
ON THE PRECIP WORDING FOR THE REST OF THE MORNING TO MAINLY PATCHY DRIZZLE.
ALSO ADDED SOME SPRINKLES OVER THE SOUTH HALF OF THE CWFA.
LATEST 88D DATA WAS SHOWING SOME SPOTTY SHRA OVER SOUTHEAST IOWA.
THE SHRA WAS IN AN AREA OF WEAK BUT DEEP FGEN WHICH THE RUC KEEPS
OVER THE SOUTH THROUGH 18Z. THE RUC WAS ALSO SHOWING THAT THE BEST RH
WAS IN THE 700-500MB LAYER WITH A DRY LAYER BELOW...SO -SHRA BASED
THIS LAYER SHOULD AMOUNT TO LITTLE MORE THE SPRINKLES. TEMPERATURES
WERE LEFT UNTOUCHED AT THIS TIME. HIGHS AROUND 60 IN THE SOUTH
SEEMS A BIT OPTIMISTIC...BUT THE CLEARING/WARMER AIR IS WITHIN A
COUNTY OF OUR SOUTHTERN BORDER...CLOSE ENOUGH TO HOLD ON TO THE CURRENT
FORECAST. ALSO THE MID 40S IN THE NORTH THIS AFTERNOON MAY BE ON
THE OPTIMISTIC SIDE WITH A STIFF EAST WIND AND LOW OVERCAST SKIES
THROUGH THE AFTERNOON. DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1214 PM CDT SAT APR 28 2012
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS SHOW AN
AMPLIFIED AND VISUALLY CONVOLUTED PATTERN ACROSS THE CONTINENT AT
THE CURRENT TIME. A CUTOFF UPPER LOW CIRCULATING OVER THE NORTHERN
ROCKIES IS WORKING TO EJECT A SHORTWAVE NORTH INTO SOUTHERN
MINNESOTA... WHICH IS HELPING TO PRODUCE THE BAND OF SHRA ACROSS
THE SOUTHERN PART OF THE FORECAST AREA AT THE CURRENT TIME.
HOWEVER... THIS FEATURE IS RUNNING INTO THE UPPER RIDGE WHICH
EXTENDS FROM CENTRAL SASKATCHEWAN SOUTHEAST THROUGH WISCONSIN...
WHICH IS SHEARING IT OUT WITH TIME AND WORKING TO DIMINISH THE
PCPN AS IT WORKS NORTHWARD. A SECONDARY SURGE OF PCPN WITH THE
UPPER TROUGH TO OUR SOUTH... COINCIDENT WITH BETTER MID-LEVEL
INSTABILITY... IS IN IOWA AND IS ALSO WORKING NORTHWARD WITH TIME.
THE LATEST HRRR AND HIGH RESOLUTION WINDOW RUNS SEEM TO HAVE A
DECENT HANDLE ON ALL OF THIS ACTIVITY... AND SUGGEST IT SHOULD
CONTINUE TO WORK UP INTO THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON... WITH ITS NORTHERN EDGE HAVING A TOUGH TIME MAKING IT
INTO THE NORTH CENTRAL AND NORTHEAST PORTION OF THE AREA GIVEN DRY
LOW LEVEL AIR BACK-FEEDING INTO THE REGION FROM THE SURFACE HIGH
POSITIONED TO OUR EAST. AS FAR AS THE LARGE SCALE PATTERN GOES...
OVERALL IT LOOKS TO DE-AMPLIFY AS WE HEAD INTO THE EARLY PART OF
NEXT WEEK... AS THE UPPER LOW TO OUR WEST SLIDES NORTH INTO CANADA
BY MONDAY AND SOMEWHAT ZONAL FLOW ESTABLISHES ITSELF OVER THE
NORTHERN TIER OF THE CONUS. HOWEVER... THE MEDIUM RANGE GUIDANCE
SUGGESTS SOME TROUGHING DEVELOPING TO OUR WEST BY MIDWEEK WHICH
WILL BRING SOME MORE ACTIVE WEATHER BACK INTO THE AREA BY MIDWEEK
INTO THE LATTER HALF OF THE WEEK. ON THE WHOLE... THE WEATHER WILL
BE SOMEWHAT UNSETTLED THROUGH THE UPCOMING WEEK... BUT AT THE
CURRENT TIME THE ONLY SYSTEM OF ANY PARTICULAR SIGNIFICANCE MAY BE
THE MIDWEEK FEATURE... WHICH COULD HAVE SOME INSTABILITY WITH
WHICH TO WORK AS IT MOVES ACROSS THE AREA ON WEDNESDAY.
AS ALLUDED TO EARLIER... EXPECT TO SEE WIDESPREAD SHRA ACTIVITY
THIS MORNING AS SOME ISENTROPIC UPGLIDE WORKS TO SUSTAIN THE
ACTIVITY CURRENTLY MOVING IN FROM OUR SOUTH EVEN THOUGH THE UPPER
SUPPORT AND DPVA WILL BE FADING WITH TIME AS THE SHORTWAVE
CONTINUES TO SHEAR OUT. LOWEST CHANCES FOR MEASURABLE PCPN WILL BE
OVER THE NORTHEAST CWFA. THE SOUTHEAST CWFA COULD SEE SOME
THUNDER... BUT AT THIS POINT FORECAST 850-500MB DIFFERENTIAL
THETA-E VALUES FROM THE NAM AND GFS SUGGEST LEAVING THAT MENTION
OUT OF THE FORECAST. CURRENT TEMPERATURES ACROSS THE AREA... ALONG
WITH THE 00Z KMPX SOUNDING AND FORECAST SOUNDINGS FROM THE RUC...
SUGGEST IT WILL BE VERY DIFFICULT TO GET ANY SNOWFLAKES FROM THIS
ACTIVITY TODAY. NOT ONLY ARE TEMPERATURES IN THE BOTTOM THOUSAND
OR SO FEET QUITE WARM... BUT AN ELEVATED WARM LAYER IS STILL NOT
COMPLETELY VANQUISHED... AND THUS FAR THERE IS MINIMAL EVIDENCE
SUGGESTING THAT WILL OCCUR. SO... REMOVED ANY MENTION OF SNOW FROM
THE FORECAST FOR TODAY. SHOULD A SUFFICIENTLY HEAVY SHRA OCCUR IT
ISN/T OUT OF THE QUESTION THAT A FEW FLAKES COULD FIND THEIR WAY
TO THE GROUND... BUT ANY SUCH OCCURRENCE WOULD BE ISOLATED AND OF
NO IMPACT SINCE IT WOULD BE SHORT-LIVED AND NON-ACCUMULATING.
LINGERED SOME LOW CHANCE POPS INTO TONIGHT AS THE MID-LEVEL
BAROCLINIC ZONE AND DEEPER MOISTURE WASHES OUT OVER THE AREA. WE
SHOULD FIND OURSELVES SUFFICIENTLY DRY ON SUNDAY AS SOME MODEST
RIDGING SURFACE AND ALOFT BECOMES ESTABLISHED OVER THE AREA... SO
EXCLUDED POPS FROM THE SUNDAY FORECAST. HOWEVER... BY SUNDAY NIGHT
WE COULD SEE SOME LIGHT PCPN WORK ACROSS THE REGION AS THE UPPER
LOW CURRENTLY TO OUR WEST WORKS INTO SOUTHERN CANADA AND HELPS
DRAG A MID-LEVEL TROUGH THROUGH THE STATE ALONG WITH A WEAK
SURFACE TROUGH. THE BEST CHANCES FOR PCPN LOOK TO BE CLOSER TO THE
MAIN UPPER SYSTEM TO OUR NORTH AND CLOSER TO THE BETTER
INSTABILITY AND LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH AND
SOUTHEAST. HOWEVER... GIVEN SUFFICIENT DEEP LAYER MOISTURE AND
SOME WEAK FORCING... LOW POPS SEEM WARRANTED FOR MUCH OF THE AREA
SUNDAY NIGHT INTO MONDAY.
MADE MINIMAL CHANGES TO THE GOING FORECAST FROM MONDAY NIGHT
THROUGH FRIDAY... MEANING THERE CONTINUES TO BE A MENTION OF PCPN
EACH DAY. BY NO MEANS DOES THE ENTIRE PERIOD LOOK LIKE A
WASHOUT... BUT THERE IS SUFFICIENT SPREAD MODEL SOLUTIONS BOTH
WITH RESPECT TO TIMING AND AMPLITUDE OF FEATURES TO INCLUDE PCPN
CHANCES EACH DAY. AT THIS POINT... THE BEST CHANCE FOR WIDESPREAD
PCPN LOOKS TO BE TUESDAY NIGHT AND WEDNESDAY AS WE INITIALLY SEE
SOME HEALTHY RETURN FLOW AND WARM AIR ADVECTION... FOLLOWED BY THE
PASSAGE OF A SURFACE LOW AND ATTENDANT SHARP COLD FRONT THROUGH
THE REGION. AFTER THIS SYSTEM MOVES THROUGH... WE LOOK TO MAINTAIN
A BAROCLINIC ZONE NEARBY FOR THE NEXT FEW DAYS AS A FEW SUCCESSIVE
SHORTWAVES MIGRATE THROUGH ON FAIRLY QUICKLY WESTERLY MID-UPPER
LEVEL FLOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
A DECREASING AREA OF -RA...WHICH IS BASICALLY BISECTING THE FA
FROM THE SE TO THE NW...WILL LIKELY BE THE MAIN PLAYER TO FINALLY
SATURATE THE LOWEST 1 KM THIS AFTN. ALTHOUGH MVFR CIGS HAVE BEEN
CONFINED TO AREAS SOUTH OF I-94...WITH IFR CIGS ALONG THE
MINNESOTA RIVER VALLEY AND SOUTHWARD THIS MORNING. E/SE WNDS AND THE
ADDED MOISTURE FROM RAINFALL THIS MORNING...WILL AID IN THE
DEVELOPMENT OF LOWER CIGS. ONLY CONCERN IS HOW FAR NE DOES THESE
LOWER CIGS MOVE THIS AFTN/EVENING...WITH THE POSSIBILITY OF FG/BR
DEVELOPING AFT MIDNIGHT.
WILL LIKE TO CONTINUE THE SAME TREND WITH SOME MODIFICATION OF
TIMING TO THE 18Z TAFS. CIGS WILL EVENTUALLY BECOME OR REMAIN MVFR
ACROSS ALL BUT RNH/EAU...BUT LOW CONFIDENCE AT THESE SITES
CONTINUE WITH THE DRY EASTERLY WNDS. ALL THE LIFT ASSOCIATED WITH
THE MORNING RAINFALL WILL END THIS AFTN...WITH ONLY DRIZZLE/BR/FG
PERSISTING THRU THE OVERNIGHT/EARLY SUNDAY. MAIN CONCERN AFT
MIDNIGHT IS FG WITH IFR/LIFR CIGS AT RWF...BUT CONTINUE THE SAME
TREND WITH ONLY IFR CIGS AND MVFR VSBYS. WNDS WILL REMAIN FROM THE
E/ESE THIS AFTN...BECOMING MORE SE SUNDAY MORNING...BUT UNDER 12 KTS.
MSP...MVFR CIGS ARND THE TERMINAL SITE...BUT NOT WIDESPREAD ENOUGH
TO BE PERSISTENT UNTIL AFT 21Z. THEREFORE...TEMPORARY CIGS OF 2.5K
SEEMS MORE APPROPRIATE. AFT 21Z...MVFR CIGS AND SOME BR IS LIKELY
WITH HIGH CONFIDENCE. DURING THE EVENING/OVERNIGHT PERIOD...CONFIDENCE
OF MVFR CIGS REMAINS HIGH...BUT THERE COULD BE A FEW BREAKS IN THE
OVERCAST IF DRIER AIR FROM THE EAST TAKES OVER. VFR CIGS SHOULD BE
DEVELOPING SUNDAY MORNING...WITH A MORE SE WND UNTIL 10 KTS AFT
14Z.
.OUTLOOK...
.SUN...VFR CONDS.
.MON-WED...PERIODS OF SHWRS/TSTMS. MVFR TO IFR CONDS POSSIBLE.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/JLT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
245 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 /THROUGH TONIGHT/...
AS OF 3:00 PM SATURDAY...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 MESOANALYSIS 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 /SUNDAY 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 /19Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...AREAS OF MVFR AT KILM/KFLO/KLBT WILL GRADUALLY IMPROVE
THROUGH THE NEXT 1-3 HOURS. CONDITIONS LIKELY REVERTING BACK TO
MVFR/IFR AFTER 00-04Z.
THOUGH FOG QUICKLY BURNED OFF THIS MORNING...LOWERED CIGS CONTINUE
TO LINGER ALONG AND NORTH OF THE STATIONARY FRONT AT KILM/KFLO/LBT.
VISIBLE SATELLITE IMAGERY DEPICTS SIGNS OF THESE LOW CLOUDS
BEGINNING TO BURN OFF...THUS EXPECT CONDITIONS TO IMPROVE WITHIN THE
NEXT HOUR OR TWO. WINDS WILL RANGE FROM NORTHEAST TO SOUTHEAST
THROUGH EARLY AFTERNOON WITH SUSTAINED WINDS 8 KTS. WINDS WILL
GRADUALLY VEER TO PREDOMINANTLY SOUTH-SOUTHEAST AT ALL SITES BY THIS
AFTERNOON WITH THE ANTICIPATED SEA BREEZE. CANNOT RULE OUT AN
ISOLATED SHOWERS/TS THIS AFTERNOON...ESPECIALLY IN AREAS NEAR THE
SEA BREEZE...POSSIBLY AFFECTING KILM. LATER TONIGHT INTO THE
OVERNIGHT HOURS...GIVEN ABUNDANT LOW LEVEL MOISTURE DEPICTED BY
MODELS EXPECT LOW LEVEL STRATUS TO DEVELOP CREATING IFR/LIFR
RESTRICTIONS THROUGH THE 14-15Z SUNDAY. WINDS ASSOCIATED WITH LOW
LEVEL JET WILL LIKELY INHIBIT ANY FOG DEVELOPMENT...THOUGH IF WINDS
BECOME LIGHT CANNOT RULE OUT BRIEF PATCHY FOG. ANTICIPATE LOW LEVEL
STRATUS TO BURN OFF THROUGHOUT THE MORNING HOURS...RETURNING TO VFR
AROUND 15Z OR SOON THEREAFTER.
EXTENDED OUTLOOK...MVFR OR BRIEF IFR VSBYS IN MORNING FOG
POSSIBLE MONDAY THROUGH WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3:00 PM SATURDAY...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.
SEAS ARE RUNNING A BIT HIGHER THAN WAVE MODELS HAD FORECAST...
GENERALLY 2-3 FT WITH THE LARGEST WAVES NEAR AND EAST OF CAPE FEAR.
SPECTRAL WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY SHOW DOMINANT
PERIODS AROUND 6 SECONDS...WITH VIRTUALLY NO SWELL ENERGY NOTED.
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...TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
315 PM EDT SAT APR 28 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL OUT JUST SOUTH OF OUR AREA LATER
TONIGHT. AS AN AREA OF LOW PRESSURE DEVELOPS TO OUR WEST SUNDAY
NIGHT...THE FRONTAL BOUNDARY WILL LIFT BACK NORTH ACROSS OUR AREA
AS A WARM FRONT. THE LOW WILL THEN PUSH EASTWARD...BRINGING
SHOWERS AND THUNDERSTORMS TO THE AREA LATE MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A TRICKY FORECAST FOR THE OVERNIGHT PERIOD AS A FRONTAL BOUNDARY
TO OUR SOUTH TRIES TO LIFT NORTHWARD TOWARD THE OHIO VALLEY. A
SHORTWAVE AND WEAK SURFACE LOW EJECTING EASTWARD OUT OF THE
PLAINS IS BEGINNING TO SHEAR OUT AS IT MOVES TOWARD THE OHIO
VALLEY. THIS IS TRIGGERING CONVECTIVE DEVELOPMENT ACROSS CENTRAL
MISSOURI AND ILLINOIS THIS AFTERNOON ALONG AN INSTABILITY
GRADIENT. THIS CONVECTION WILL SPREAD EASTWARD ALONG THE
INSTABILITY GRADIENT OVER THE NEXT SEVERAL HOURS.
LATEST RUC13 RUNS SHOWS THE NORTHERNMOST EXTENT OF THIS GRADIENT TO
PUSH NORTHWARD INTO OUR KENTUCKY COUNTIES AROUND 23Z. THIS IS ALSO
CONFIRMED BY SURFACE OBSERVATIONS...WITH TEMPS NEAR 75 IN
LOUISVILLE...AND ONLY THE UPPER 50S ACROSS OUR SOUTHERN ZONES.
TEMPERATURES ACROSS OUR SOUTH WILL LIKELY REACH THE 70S BY THE
EARLY EVENING AS THE BOUNDARY SHIFTS SLIGHTLY NORTHWARD...AND SOME
CLEARING MAKES IT INTO THE AREA. THEREFORE...IT APPEARS THE BEST
CHANCES FOR SURFACE BASED CONVECTION DURING THE EVENING WILL BE
ALONG AND SOUTH OF OUR SOUTHERNMOST COUNTIES. SOME ELEVATED
CONVECTION COULD OCCUR JUST NORTH OF THESE COUNTIES AS WELL AND
AS THE SURFACE LOW MOVES BY. HAVE THEREFORE FORECAST LIKELY POPS
IN THESE AREAS...WITH LOW END CHANCE POPS ELSEWHERE. DECENT SHEAR
PROFILES COULD COMBINE WITH CONVECTION ALONG THIS BOUNDARY TO
INDUCE POSSIBLE LARGE HAIL AND STRONG WINDS MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AFTER SUNSET...THE SEVERE THREAT WILL
DIMINISH AS WE LOSE INSOLATION AND SURFACE INSTABILITY DECREASES.
OVERALL ACTIVITY WILL DIMINISH BY MIDNIGHT...WITH SOME LINGERING
SHOWERS JUST NORTH OF THE SAGGING FRONTAL BOUNDARY. HAVE KEPT
CHANCE POPS ACROSS THE SOUTHERN ZONES DURING THE OVERNIGHT PERIOD.
ALTHOUGH CURRENT TEMPERATURES ACROSS THE NORTH ARE IN THE LOW 40S
WITH A FEW UPPER 30S...ABUNDANT CLOUD COVER SHOULD PREVENT
TEMPERATURES FROM FALLING INTO THE LOW 30S OVERNIGHT. A STRONG
TEMPERATURE GRADIENT WILL LIKELY REMAIN IN PLACE OVERNIGHT...WITH
UPPER 30S ACROSS THE NORTH...TO NEAR 50 ACROSS THE SOUTH.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
FRONTAL BOUNDARY WILL STALL OUT JUST SOUTH OF THE AREA SUNDAY
MORNING. AN ONGOING CHANCE FOR SHOWERS WILL OCCUR JUST NORTH OF
THIS BOUNDARY...ACROSS OUR SOUTHERN ZONES THROUGHOUT THE DAY.
ELSEWHERE...UNDER PARTLY TO MOSTLY CLOUDY SKIES...ENOUGH SUN
SHOULD MAKE IT THROUGH THE CLOUD COVER TO HELP TEMPERATURES RISE
INTO THE LOW 60S ACROSS THE AREA. CLOSER TO THE FRONTAL
BOUNDARY...ACROSS THE SOUTH...TEMPERATURES COULD REACH THE LOW
70S.
WEAK LOW PRESSURE APPROACHING FROM THE EAST WILL HELP PULL THE
FRONTAL BOUNDARY ACROSS THE OHIO VALLEY OVERNIGHT SUNDAY NIGHT.
THIS WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS MAINLY
ACROSS THE WEST DURING THE OVERNIGHT HOURS. THE LOW WILL THEN PUSH
NORTHEASTWARD ACROSS THE EASTERN GREAT LAKES MONDAY
NIGHT...PRODUCING ENOUGH CONVERGENCE TO PRODUCE SHOWERS AND
THUNDERSTORMS ACROSS MOST OF THE AREA. DURING THE DAY MONDAY OUR
AREA WILL BECOME WARM SECTORED. WITH RETURN FLOW IN PLACE...
TEMPERATURES WILL RISE INTO THE MID TO UPPER 70S AREA WIDE. A
FEW 80S CAN BE EXPECTED ACROSS OUR SOUTH AS WELL. MONDAY NIGHT
WILL ALSO BE A WARM ONE...WITH MID 50S TO UPPER 60S EXPECTED.
ONCE THE LOW PASSES...A WEAK BOUNDARY WILL LAY OUT ACROSS THE OHIO
RIVER MONDAY NIGHT. THIS WILL BECOME THE FOCUS FOR A CHANCE OF SHOWERS
AND THUNDERSTORMS ACROSS THESE ZONES INTO TUESDAY MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A MID LEVEL SHORT WAVE WILL LIFT NORTHEAST ACROSS THE REGION TUESDAY
THROUGH TUESDAY NIGHT AS RIDGING ALOFT TRIES TO BUILD INTO THE
EASTERN UNITED STATES. THIS WILL LEAD TO AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH TUESDAY AFTERNOON...CONTINUING
INTO TUESDAY NIGHT. AS THE SHORT WAVE PUSHES OFF TO THE
EAST...EXPECT PCPN TO TAPER OFF LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. WITH RIDGING BUILDING ACROSS THE AREA AND BROAD
SOUTHWESTERLY FLOW...TEMPERATURES SHOULD REMAIN ABOVE NORMAL THROUGH
MID WEEK. HIGHS ON TUESDAY WILL BE IN THE MID TO UPPER 70S...WARMING
INTO THE LOWER 80S BY WEDNESDAY.
A COLD FRONT WILL PUSH DOWN FROM THE NORTHWEST THURSDAY INTO FRIDAY.
THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. SOME
TIMING DIFFERENCES EXISTS BETWEEN THE MODELS...BUT IT APPEARS THE
BEST CHANCE FOR PCPN WOULD BE THURSDAY AFTERNOON INTO THURSDAY
NIGHT. COOLER AIR MOVING IN BEHIND THE FRONT WILL LEAD TO A RETURN
TO NEAR NORMAL TEMPERATURES HEADING INTO THE WEEKEND.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THUNDERSTORMS ASSOCIATED WITH A SHORT WAVE ALOFT HAVE GENERALLY MOVED
EAST OF TAF SITES. EXPECT THUNDERSTORMS TO PERSIST FOR A COUPLE
HOURS AT LUK NEAR A RESIDUAL BOUNDARY. MORE CONVECTION MAY DEVELOP
AT CVG LATER THIS AFTERNOON AS INSTABILITY RECOVERS AHEAD OF A
WARM FRONT. UPSTREAM OBSERVATIONS AND MODEL SOUNDINGS INDICATE
MVFR CEILINGS TONIGHT...IMPROVING TO VFR ON SUNDAY. WITH THE WARM
FRONT EXPECTED TO STAY SOUTH...WINDS WILL REMAIN OUT OF THE EAST
WITH SPEEDS AVERAGING 10 KNOTS.
OUTLOOK...THUNDERSTORMS ALONG WITH MVFR CEILINGS AND VISIBILITIES
ARE POSSIBLE AT TIMES FROM MONDAY NIGHT THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS TULSA OK
1225 PM CDT SAT APR 28 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
WIDESPREAD CLOUDINESS WILL MAINTAIN LOW VFR TO PERIODIC MVFR
CEILINGS THROUGH MUCH OF THE FORECAST PERIOD. THE COLD FRONT
CURRENTLY JUST SOUTH OF KBVO MAY SLOWLY SAG A BIT FURTHER SOUTH
THIS EVENING...THOUGH CONFIDENCE REMAINS LOW IF AND/OR WHEN IT WILL
PASS THROUGH THE KTUL/KRVS SITES. WILL MAINTAIN OVERNIGHT AND
EARLY MORNING CONVECTIVE CHANCES FOR NE OK NEAR THE BOUNDARY.
&&
.PREV DISCUSSION... /ISSUED 1126 AM CDT SAT APR 28 2012/
..UPDATE...
DISCUSSION...
FRONTAL BOUNDARY CLEARING DEFINED WITHIN OKLAHOMA MESONET DATA
WHILE EXPANSIVE LOW CLOUDS HAVE LIMITED THE THERMAL GRADIENT
ACROSS THE FRONT THUS FAR. ANY MOVEMENT OF THE FRONT THROUGH THE
REMAINDER OF THE AFTERNOON IS EXPECTED TO BE MINIMAL...POSSIBLY
PUSHING A BIT FURTHER SOUTH IF THE LATEST RUC GUIDANCE IS
ACCURATE. OTHERWISE...THE WIDESPREAD CLOUDINESS WILL REMAIN IN
PLACE AND FOR AREAS SOUTH OF THE FRONT WHERE CLOUDS DO BREAK...A
QUICK WARM UP IS LIKELY. FORECAST SOUNDINGS ACROSS THE AREA
MAINTAIN A SUBSTANTIAL CAPPING INVERSION THROUGH THE AFTERNOON AND
THE UPDATED POPS WILL REALIGN THE SLIGHT CHANCES TO THE
IMMEDIATE VICINITY OF THE FRONT. OTHERWISE...MOST FORECAST
ELEMENTS ARE ON TRACK WITH MINOR ADJUSTMENTS ALONG THE CURRENT
FRONTAL ZONE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 65 78 65 80 / 50 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 / 60 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 / 50 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.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
1126 AM CDT SAT APR 28 2012
...UPDATE...
.DISCUSSION...
FRONTAL BOUNDARY CLEARING DEFINED WITHIN OKLAHOMA MESONET DATA
WHILE EXPANSIVE LOW CLOUDS HAVE LIMITED THE THERMAL GRADIENT
ACROSS THE FRONT THUS FAR. ANY MOVEMENT OF THE FRONT THROUGH THE
REMAINDER OF THE AFTERNOON IS EXPECTED TO BE MINIMAL...POSSIBLY
PUSHING A BIT FURTHER SOUTH IF THE LATEST RUC GUIDANCE IS
ACCURATE. OTHERWISE...THE WIDESPREAD CLOUDINESS WILL REMAIN IN
PLACE AND FOR AREAS SOUTH OF THE FRONT WHERE CLOUDS DO BREAK...A
QUICK WARM UP IS LIKELY. FORECAST SOUNDINGS ACROSS THE AREA
MAINTAIN A SUBSTANTIAL CAPPING INVERSION THROUGH THE AFTERNOON AND
THE UPDATED POPS WILL REALIGN THE SLIGHT CHANCES TO THE
IMMEDIATE VICINITY OF THE FRONT. OTHERWISE...MOST FORECAST
ELEMENTS ARE ON TRACK WITH MINOR ADJUSTMENTS ALONG THE CURRENT
FRONTAL ZONE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 65 79 65 / 20 70 50 70
FSM 83 64 84 64 / 10 30 30 30
MLC 80 65 80 66 / 10 50 20 40
BVO 72 61 79 63 / 20 70 60 80
FYV 77 62 80 62 / 10 40 40 40
BYV 78 62 80 62 / 10 40 40 50
MKO 80 64 81 64 / 10 50 40 50
MIO 76 63 78 63 / 20 60 60 70
F10 79 65 80 65 / 10 60 30 50
HHW 82 65 82 65 / 10 30 20 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
552 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD LATE TODAY TODAY ALONG A
FRONTAL ZONE DRAPED FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN
MID-ATLANTIC COAST. THIS WILL CREATE A FEW PERIODS OF LIGHT RAIN FOR
MUCH OF CENTRAL PA THROUGH EARLY TONIGHT. A LARGE AREA OF HIGH
PRESSURE WILL NOSE SOUTHEAST FROM THE GREAT LAKES TONIGHT AND
SUNDAY...PROVIDING FAIR WEATHER AND MODERATING TEMPERATURES FOR
SUNDAY AND MONDAY. 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/...
SHIELD OF OVC ALTOCU/ALTO STRATUS /CENTRAL AND WEST/...AND
CIRROSTRATUS /EAST/...WILL LOWER AND THICKEN UP THROUGH THE EARLY
EVENING AS AN AREA OF LIGHT PRECIP RACES IN FROM NERN OHIO AND SWRN
PENN. RECENT REPORT VIA ONE OF OUR LONG-TIME NWS EMPLOYEES RESIDING
IN ALTOONA NOTED SOME SNOW PELLETS MIXING IN WITH THE LIGHT RAIN
BEGINNING THERE OVER THE PAST HOUR.
17Z RUC CONFIRMS AN APPROX 30NM WIDE CHANNEL OF NEAR 0C WET BULB
TEMPS IN THE 900-950 MB LAYER /WITH SUB-FREEZING WET BULBS ALOFT/
CAPABLE OF MAINTAINING SOME WET SNOW/PELLETS ALL THE WAY TO THE
GROUND. PAINTED THIS SPECKLING OF LIGHT WEST SNOW IN OUR WEATHER
GRIDS INTO THE EARLY EVENING HOURS ACROSS WEST-CENTRAL AND CENTRAL
PENN /BUT MAINLY AT ELEVATIONS AOA 2000 FT MSL/. NO ACCUMS WILL BE
POSSIBLE BASED ON SFC TEMPS AND GENERALLY VERY LIGHT PRECIP RATES.
TEMPS ARE BASICALLY AT THEIR MAXES IN MOST PLACES...AND WILL EVEN
FALL SEVERAL DEG F ACROSS THE CENTRAL AND WESTERN ZONES AS THE
PRECIP SHIELD SPREADS INTO THE VERY DRY LLVL AIR RESIDING HERE
HIGHLIGHTED BY SFC DEWPOINTS IN THE MID TEENS TO LOWER 20S.
WILL MAINTAIN THE HIGH POPS /AROUND 90 PERCENT/ ACROSS THE CENTRAL
AND SOUTHERN ZONES...BUT EMPHASIZE THAT QPF FOR THIS ENTIRE EVENT
WILL BE AOB ONE TENTH OF AN INCH BASED ON SHORT TERM MODEL GUIDANCE
AND HOURLY PRECIP VIA UPSTREAM OBS. A FEW SPOTS ACRS THE SRN TIER OF
PENN COULD APPROACH 0.20 OF AN INCH FOR RAINFALL OVER THE UPCOMING
12 HOURS OR SO.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN 22-02Z. DECREASING POPS WILL DEVELOP FROM FROM
NW-SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END TO THE
RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE PRESSES 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 /20Z SATURDAY 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 RAINFL 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...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
353 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD LATE TODAY TODAY ALONG A
FRONTAL ZONE DRAPED FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN
MID-ATLANTIC COAST. THIS WILL CREATE A FEW PERIODS OF LIGHT RAIN FOR
MUCH OF CENTRAL PA THROUGH EARLY TONIGHT. A LARGE AREA OF HIGH
PRESSURE WILL NOSE SOUTHEAST FROM THE GREAT LAKES TONIGHT AND
SUNDAY...PROVIDING FAIR WEATHER AND MODERATING TEMPERATURES FOR
SUNDAY AND MONDAY. 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/...
SHIELD OF OVC ALTOCU/ALTO STRATUS /CENTRAL AND WEST/...AND
CIRROSTRATUS /EAST/...WILL LOWER AND THICKEN UP THROUGH THE EARLY
EVENING AS AN AREA OF LIGHT PRECIP RACES IN FROM NERN OHIO AND SWRN
PENN. RECENT REPORT VIA ONE OF OUR LONG-TIME NWS EMPLOYEES RESIDING
IN ALTOONA NOTED SOME SNOW PELLETS MIXING IN WITH THE LIGHT RAIN
BEGINNING THERE OVER THE PAST HOUR.
17Z RUC CONFIRMS AN APPROX 30NM WIDE CHANNEL OF NEAR 0C WET BULB
TEMPS IN THE 900-950 MB LAYER /WITH SUB-FREEZING WET BULBS ALOFT/
CAPABLE OF MAINTAINING SOME WET SNOW/PELLETS ALL THE WAY TO THE
GROUND. PAINTED THIS SPECKLING OF LIGHT WEST SNOW IN OUR WEATHER
GRIDS INTO THE EARLY EVENING HOURS ACROSS WEST-CENTRAL AND CENTRAL
PENN /BUT MAINLY AT ELEVATIONS AOA 2000 FT MSL/. NO ACCUMS WILL BE
POSSIBLE BASED ON SFC TEMPS AND GENERALLY VERY LIGHT PRECIP RATES.
TEMPS ARE BASICALLY AT THEIR MAXES IN MOST PLACES...AND WILL EVEN
FALL SEVERAL DEG F ACROSS THE CENTRAL AND WESTERN ZONES AS THE
PRECIP SHIELD SPREADS INTO THE VERY DRY LLVL AIR RESIDING HERE
HIGHLIGHTED BY SFC DEWPOINTS IN THE MID TEENS TO LOWER 20S.
WILL MAINTAIN THE HIGH POPS /AROUND 90 PERCENT/ ACROSS THE CENTRAL
AND SOUTHERN ZONES...BUT EMPHASIZE THAT QPF FOR THIS ENTIRE EVENT
WILL BE AOB ONE TENTH OF AN INCH BASED ON SHORT TERM MODEL GUIDANCE
AND HOURLY PRECIP VIA UPSTREAM OBS. A FEW SPOTS ACRS THE SRN TIER OF
PENN COULD APPROACH 0.20 OF AN INCH FOR RAINFALL OVER THE UPCOMING
12 HOURS OR SO.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN 22-02Z. DECREASING POPS WILL DEVELOP FROM FROM
NW-SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END TO THE
RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE PRESSES 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 /20Z SATURDAY THROUGH THURSDAY/...
THICKENING MID AND HIGH CLOUDS WILL CONTINUE OVERSPREAD THE REGION
THIS AFTERNOON AND EVENING BUT VFR CONDS WILL PREVAIL...EVEN DURING
SOME PERIODS OF LIGHT RAIN. SOME WET SNOWFLAKES/PELLETS COULD BE
MIXED IN FROM KDUJ AND KFIG...ESE THROUGH KUNV AND 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 PRECIP THIS EVENING...BUT LATEST
BLEND OF THE 09Z SREF...12Z NAM AND 17Z RUC QPF INDICATES THAT SOME
VERY LIGHT AMTS OF RAIN ARE POSSIBLE THERE LATE TODAY AND EARLY TNGT.
MVFR CIGS APPEAR LIKELY OVR AT AOO/JST FM LATE THIS EVENING INTO THE
FIRST PART OF TNT...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...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
256 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD LATE TODAY TODAY ALONG A
FRONTAL ZONE DRAPED FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN
MID-ATLANTIC COAST. THIS WILL CREATE A FEW PERIODS OF LIGHT RAIN FOR
MUCH OF CENTRAL PA THROUGH EARLY TONIGHT. A LARGE AREA OF HIGH
PRESSURE WILL NOSE SOUTHEAST FROM THE GREAT LAKES TONIGHT AND
SUNDAY...PROVIDING FAIR WEATHER AND MODERATING TEMPERATURES FOR
SUNDAY AND MONDAY. 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 /THROUGH TONIGHT/...
SHIELD OF OVC ALTOCU/ALTO STRATUS /CENTRAL AND WEST/...AND
CIRROSTRATUS /EAST/...WILL LOWER AND THICKEN UP THROUGH THE EARLY
EVENING AS AN AREA OF LIGHT PRECIP RACES IN FROM NERN OHIO AND SWRN
PENN. RECENT REPORT VIA ONE OF OUR LONG-TIME NWS EMPLOYEES RESIDING
IN ALTOONA NOTED SOME SNOW PELLETS MIXING IN WITH THE LIGHT RAIN
BEGINNING THERE OVER THE PAST HOUR.
17Z RUC CONFIRMS AN APPROX 30NM WIDE CHANNEL OF NEAR 0C WET BULB
TEMPS IN THE 900-950 MB LAYER /WITH SUB-FREEZING WET BULBS ALOFT/
CAPABLE OF MAINTAINING SOME WET SNOW/PELLETS ALL THE WAY TO THE
GROUND. PAINTED THIS SPECKLING OF LIGHT WEST SNOW IN OUR WEATHER
GRIDS INTO THE EARLY EVENING HOURS ACROSS WEST-CENTRAL AND CENTRAL
PENN /BUT MAINLY AT ELEVATIONS AOA 2000 FT MSL/. NO ACCUMS WILL BE
POSSIBLE BASED ON SFC TEMPS AND GENERALLY VERY LIGHT PRECIP RATES.
TEMPS ARE BASICALLY AT THEIR MAXES IN MOST PLACES...AND WILL EVEN
FALL SEVERAL DEG F ACROSS THE CENTRAL AND WESTERN ZONES AS THE
PRECIP SHIELD SPREADS INTO THE VERY DRY LLVL AIR RESIDING HERE
HIGHLIGHTED BY SFC DEWPOINTS IN THE MID TEENS TO LOWER 20S.
WILL MAINTAIN THE HIGH POPS /AROUND 90 PERCENT/ ACROSS THE CENTRAL
AND SOUTHERN ZONES...BUT EMPHASIZE THAT QPF FOR THIS ENTIRE EVENT
WILL BE AOB ONE TENTH OF AN INCH BASED ON SHORT TERM MODEL GUIDANCE
AND HOURLY PRECIP VIA UPSTREAM OBS. A FEW SPOTS ACRS THE SRN TIER OF
PENN COULD APPROACH 0.20 OF AN INCH FOR RAINFALL OVER THE UPCOMING
12 HOURS OR SO.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN 22-02Z. DECREASING POPS WILL DEVELOP FROM FROM
NW-SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END TO THE
RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE PRESSES 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 /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 FRIDAY/...
THE ONLY FORECAST TROUBLE WILL BE SUNDAY NIGHT AS
NEARLY IDEAL RADIATIONAL COOLING WILL AGAIN PROVIDE THE LIKELIHOOD
OF A FREEZE OVER MUCH IF NOT ALL OF THE AREA. WILL HOLD OFF ON ANY
FURTHER FLAGS AT THIS POINT...BUT MONDAY AM LOOKS A DEG OR TWO
COLDER THAN SUN AM.
GENERALLY PROGRESSIVE WEST TO SWRLY UPPER FLOW IS EXPECTED THROUGH
THE LONG TERM PERIOD. THIS WILL BRING SEVERAL FRONTS AND CHANCES
FOR...MAINLY LIGHT...PCPN TO CENTRAL PA.
GRADUAL WARMING TREND CONTINUES MONDAY. HIGHS THROUGH NEXT WEEK
INCREASE ABOUT 5F EACH DAY IN RETURN FLOW ON BACK OF HIGH. TEMPS
WILL TOP OUT IN THE 70S FOR THE SECOND HALF OF THE WEEK...WITH
80S EVEN POSSIBLE IN SPOTS. INDIVIDUAL SHORTWAVES...WHICH ARE
VERY HARD TO RESOLVE AT THESE RANGES...WILL MODULATE OPPORTUNITIES
OF PCPN. THE NEXT HIGH CHC OF PRECIP WILL BE DURING A TIME OF MCS-
FAVORABLE CONDITIONS MONDAY NIGHT. WILL GO WITH POPS INCREASING TO
50 PCT IN THE WEST FOR MONDAY NIGHT...AND 40S FOR TUESDAY. THEN
PERPETUAL 30 POPS WILL BE CARRIED ON THRU FRIDAY.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THICKENING MID AND HIGH CLOUDS WILL CONTINUE OVERSPREAD THE REGION
THIS AFTERNOON AND EVENING BUT VFR CONDS WILL PREVAIL...EVEN DURING
SOME PERIODS OF LIGHT RAIN. SOME WET SNOWFLAKES/PELLETS COULD BE
MIXED IN FROM KDUJ AND KFIG...ESE THROUGH KUNV AND 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 PRECIP THIS EVENING...BUT LATEST
BLEND OF THE 09Z SREF...12Z NAM AND 17Z RUC QPF INDICATES THAT SOME
VERY LIGHT AMTS OF RAIN ARE POSSIBLE THERE LATE TODAY AND EARLY TNGT.
MVFR CIGS APPEAR LIKELY OVR AT AOO/JST FM LATE THIS EVENING INTO THE
FIRST PART OF TNT...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...
HARD 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...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...GARTNER/STEINBUGL
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
206 PM EDT SAT APR 28 2012
.SYNOPSIS...
A SURFACE FRONT ACROSS NORTHEAST GEORGIA AND THE UPSTATE OF SOUTH
CAROLINA WILL SLOWLY LIFT NORTH TONIGHT AS A WARM FRONT...BUT
WILL RETURN BACK TO THE SOUTHWEST LATE ON SUNDAY. ON MONDAY...HIGH
PRESSURE TO THE NORTHEAST WILL AFFECT THE REGION WITH COOLER
TEMPERATURES. THE HIGH WILL MOVE OFF THE EAST COAST ON TUESDAY...
ALLOWING A RETURN OF WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 130 PM... NO MAJOR CHANGES TO EARLY AFTERNOON FORECAST.
SATELLITE IMAGERY SHOWS CLOUDS EAST OF MOUNTAINS ARE ERODING FROM
SOUTHWEST TO NORTHEAST.
AT 1030 AM... CLOUDS NORTH OF SURFACE BOUNDARY EAST
OF MOUNTAINS WILL CONTINUE INTO THE AFTERNOON... BUT EROSION IS
ALREADY OCCURRING AROUND THE WESTERN AND SOUTHWESTERN PERIPHERY OF
THE CWA AND IN THE FOOTHILLS. MOIST LOW-LEVEL AIR HAVING A HARD
PENETRATING TOO FAR WEST ACROSS THE MOUNTAINS... WHICH IS
TYPICAL... SO THAT PART OF CWA WILL EXPERIENCE A FAIR AMOUNT OF
SUN UNTIL CONVECTIVE CLOUDS FILL IN SOME OF THE GAPS. THE MODELS
ARE NEARLY UNANIMOUS IN THEIR AGREEMENT REGARDING A GRADUAL
NORTHWARD MOVEMENT OF THE SURFACE BOUNDARY ACROSS THE FORECAST
AREA THIS AFTERNOON AND EVENING. AS THAT OCCURS... THE WEAK CAD-
LIKE RIDGE OF HIGH PRESSURE EAST OF THE MOUNTAINS WILL RECEDE...
BUT APPEARS THAT QUITE A BIT OF LOW- LEVEL MOISTURE WILL REMAIN
BEHIND. RUC INDICATES THAT SOME MODEST CAPE... 500+ J/KG... WILL
EXIST THIS AFTERNOON NEAR BOUNDARY OVER SOUTHERN PORTION OF CWA.
MODEL PROFILES SHOW THAT A FAIRLY WARM LAYER WOULD HAVE TO BE
OVERCOME TO RELEASE THE CAPE... SO DOES NOT APPEAR LIKELY THAT
CONVECTIVE PRECIPITATION WILL DEVELOP THERE. A SLIGHTLY BETTER
CHANCE EXISTS OVER THE MOUNTAINS WHERE HIGHER CAPE CONSISTING OF
INCREASINGLY UNSTABLE LOW AND MID-LEVEL LAPSE RATES WILL SPREAD
OVER THOSE ZONES FROM THE SOUTHWEST BY LATE AFTERNOON. HEATING
OVER THE HIGHER TERRAIN COULD PROMOTE DEVELOPMENT OF WIDELY
SCATTERED SHOWERS OR THUNDERSTORMS.
PREVIOUS DISCUSSION...
AT 320 AM...STATIONARY FRONT OVER THE AREA IS KEEPING TD/S HIGH
WHILE THE MID AND UPPER LEVELS SLOWLY BEGIN TO BECOME FREE OF DEBRIS
CLOUDINESS. DENSE FG IS SETTING UP ACROSS THE WRN UPSTATE AND NE
GA...HOWEVER VISIBILITY IS GOING BACK AND FORTH BTW 1/4SM RANGE AND
BTW 1SM-2SM. ENOUGH VARIABILITY AND NOT WIDESPREAD ENOUGH TO ISSUE A
DFA. OVER NEAR CLT AND THE NW PIEDMONT...LLVL STCU IS FORMING ALONG
A WEAK WEDGE FRONT. EXPECT THESE CLOUDS TO PERSIST THROUGH ABOUT MID
DAY...PERHAPS A BIT LONGER AS H85 WARM FRONT ADVANCES NORTH OVER THE
STRENGTHENING. NOT SEEING ENOUGH DEPTH OF MOISTURE OR ELEVATED
INSTABILITY TO INCLUDE PRECIPITATION. CLOUDS WILL BE THE MAIN WORRY
AS FAR AS MAX TEMPS GO. RIGHT NOW A DECENT TEMP GRADIENT IS
ADVERTISED N/S. MAXES SHOULD BE IN THE M80S SOUTH WHILE THE NRN
PIEDMONT SHOULD ONLY GET INTO THE MID TO UPPER 60S. ISOL CONVECTION
IS POSSIBLE ACROSS THE NC MTNS THIS AFTERNOON...AS LLVL WINDS SHIFT
S/LY AND SUPPLY MECHANICAL LIFT TO A MODESTLY UNSTABLE ENVIRONMENT.
MAXES IN THE MTN VALLEYS WILL BE IN M70S.
NO GOOD CHANCE PRECIP OVERNIGHT AS WEDGE DISSIPATES AND SHIFTS EAST.
ALSO THE FRONTAL BOUNDARY WILL BE LOCATED OVER SRN VA. A GOOD AMOUNT
OF CLEARING IS ANTICIPATED OVERNIGHT...HOWEVER THE H100-H85 LAYER
MOISTURE REMAINS MOIST ENOUGH TO SUPPORT SCT STCU ACROSS AT LEAST
THE NRN ZONES. THIS COMBINED WITH LLVL WAA WILL KEEP MIN TEMPS A
COUPLE CATS ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE SHORT RANGE PART OF THE FORECAST STILL
LOOKS LIKE IT WILL BE DOMINATED BY LOW LEVEL FORCING AND MESOSCALE
PROCESSES. AN UPPER ANTICYCLONE WILL REMAIN IN PLACE OVER THE DEEP
SOUTH WITH AN UPPER RIDGE AMPLIFYING OVERHEAD ON SUNDAY AND SUNDAY
NIGHT. ALTHO THE RIDGE FLATTENS SOMEWHAT LATE MONDAY AND MONDAY
NIGHT...ALL THE SHORT WAVES AND UPPER FORCING REMAINS SHUNTED TO THE
NORTH OF THE REGION. THE LOW LEVEL FORCING IS STILL EXPECTED TO COME
IN THE FORM OF A BACK DOOR COLD FRONT THAT WILL MOVE INTO THE WRN
PIEDMONT AND NC FOOTHILLS ON SUNDAY AFTERNOON. THE TIMING IS
QUESTIONABLE...WITH THE NAM BEING A BIT FASTER TO ESTABLISH THE
MOIST E/NE FLOW. THE FORECAST FAVORS THE GFS A BIT MORE THAN THE NAM
IN THAT PRECIP CHANCES DO NOT CLIMB INTO THE CHANCE RANGE UNTIL THE
EARLY EVENING OVER THE NW PIEDMONT. HIGH TEMPS WERE NUDGED TOWARD A
GUIDANCE BLEND. THE FRONT SHOULD CONTINUE TO PUSH SW ACROSS THE AREA
EAST OF THE MTNS SUNDAY NIGHT. CONVERGENCE ALONG THE BOUNDARY AND
EASTERLY UPSLOPE SUGGEST KEEPING PRECIP IN THE FORECAST OVERNIGHT...
WITH THE HIGHEST CHANCES NEAR THE BLUE RIDGE. ON MONDAY...THE
SITUATION LOOKS WEDGE LIKE WITH A PIECE OF THE SURFACE HIGH BROKEN
OFF NEAR THE MID ATLANTIC COAST. IN THESE SITUATIONS...THE NAM SEEMS
TO HAVE A BETTER HANDLE ON KEEPING THE COLD AIR DAMMING IN PLACE
WHILE THE GFS IS TOO QUICK TO DESTROY IT. CLOUDINESS AND LIGHT
PRECIP SHOULD BE EXPECTED IN THE MORNING...WITH LITTLE IMPROVEMENT
OVER THE USUAL DAMMING LOCATIONS UNTIL MAYBE VERY LATE IN THE DAY.
SOME LOCATIONS WILL NOT MAKE IT OUT OF THE 60S. WILL NOT MAKE ANY
BIG CHANGES TO HIGH TEMPS...BUT SEE WHERE THEY COULD BE A CATEGORY
TOO HIGH IF PRECIP DEVELOPS TO A GREATER EXTENT THAN EXPECTED. LIGHT
PRECIP MAY CONTINUE NEAR THE BLUE RIDGE MONDAY NIGHT WITH THE LOW
LEVEL UPGLIDE...AND TEMPS SHOULD REMAIN MILD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE MEDIUM RANGE LOOKS FAIRLY UNEVENTFUL
WITH FLAT UPPER RIDGING IN PLACE THROUGH MOST OF THE PERIOD...AND
SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. AS A RESULT...THE
MODELS LOOK ALMOST SUMMERLIKE...AND FAVOR MAINLY DIURNAL LOW END
CHANCES OF PRECIP THAT FAVOR THE MTNS. DO NOT SEE MUCH OF A REASON
TO MAKE MANY CHANGES TO THE ONGOING FORECAST...UNTIL LATE IN THE
PERIOD. THE LATEST GFS SHOWS A SHORT WAVE MOVING THROUGH ON FRIDAY
AFTERNOON. WHILE THE TIMING IS UNCERTAIN...BOTH MODELS DROP THE NEXT
FRONT DOWN FROM THE NORTH IN THE AFTERNOON...SO PRECIP CHANCES WILL
PROBABLY BE A BIT BETTER THEN COMPARED TO MID WEEK. WITH THAT IN
MIND...THE FORECAST WILL BE BUMPED UP A BIT.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...SATELLITE IMAGERY SHOWS THE MVFR CLOUD DECK ENCOMPASSING
KCLT IS SHOWING DEFINITE SIGNS OF EROSION... BUT IT WILL STIL TAKE A
LITTLE TIME FOR THE IMPROVEMENT TO REACH THE TERMINAL AREA. BASED ON
SATELLITE AND LATEST LAMP GUIDANCE... CLOUD BASE NEAR 2K FT SHOULD
INCREASE TO AROUND 35 HND FT AS IT DISSIPATES BETWEEN 21Z AND 00Z.
THEREAFTER... EXPECT SCATTERED CLOUDS OVERNIGHT. NEITHER THE NAM OR
GFS INDICATE VISIBILITY RESTRICTION... SO WILL NOT INCLUDE ANY IN
FORECAST AT THE PRESENT TIME. NORTHEAST WIND LESS THAN 10 KT WILL
BECOME LIGHT SOUTHEAST TONIGHT THEN LIGHT AND VARIABLE DURING THE
EARLY MORNING HOURS.
ELSEWHERE... VISIBLE IMAGERY... EXPERIMENTAL CIMSS GOES-R
PRODUCTS... AND SURFACE OBSERVATIONS INDICATE LARGE AREA OF MVFR
CEILING... BETWEEN 2 AND 3K FT... EXTENDS FROM VICINITY KAND
EASTWARD AND NORTHWARD TO ALL TERMINAL SITES EXCEPT KAVL. KAVL WILL
HAVE SCATTERED CLOUDS 4 TO 6 K FT PRODUCING ONLY AN OCCASIONAL
CEILING. MVFR CEILING AT OTHER SITES WILL IMPROVE FROM SOUTHWEST TO
NORTHEAST BECOMING SCATTERED AFTER 00Z. NEITHER THE NAM OR THE GFS
INDICATES WIDESPREAD VISIBILITY RESTRICTIONS SO WILL NOT INCLUDE ANY
IN THE THE FORECASTS AT THE PRESENT TIME. LIGHT NORTHEAST TO EAST
WIND WILL BECOME LIGHT AND VARIABLE OVERNIGHT.
MVFR STRATUS AND STRATOCUMULUS WILL PERSIST INTO THE
AFTERNOON EXCEPT AT KAVL WHERE SCATTERED TO BROKEN CLOUDS NEAR 4K FT
WILL EXIST. BY 20Z EXPECT CLOUD BASES TO LIFT TO 3-4K FT. VISIBILITY
UNRESTRICTED. ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE OVER HIGHER
TERRAIN NEAR KAVL AFTER 18Z.
OUTLOOK... A WEAK COLD FRONT WILL DROP INTO THE AREA FROM THE
NORTHEAST SUNDAY NIGHT CAUSING MVFR AND LOCAL IFR CONDITIONS IN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. THE FRONT WILL REMAIN
IN THE VICINITY THROUGH MID WEEK...RESULTING IN A CONTINUATION OF
UNSETTLED WEATHER... PRIMARLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOW CEILING AND VISIBILITY.
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...LGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 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...THROUGH 18Z SUNDAY
1239 PM CDT SAT APR 28 2012
THE 800 TO 600 MB FRONTOGENESIS WILL GRADUALLY WEAKEN THIS
AFTERNOON. AS THIS OCCURS...THE RAIN WILL DISSIPATE AT BOTH TAF
SITES AROUND 28.21Z. ONCE THE RAIN ENDS...THE CEILINGS WILL BECOME
IFR AT KRST AND MVFR AT KLSE. AS EASTERLY WINDS BRING DRIER AIR
INTO WESTERN WISCONSIN LATE THIS EVENING...THE CEILINGS WILL
GRADUALLY RISE INTO THE 3500 TO 4500 FEET RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 PM CDT SAT APR 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1123 AM CDT SAT APR 28 2012
.UPDATE...
NAM SHOWS 700 MB RH GRADUALLY DRYING THIS AFTERNOON AS 700 MB
UPWARD MOTION ENDS AND 850/700 MB MOISTURE CONVERGENCE WEAKENS. THE
DRYING FROM THE NORTHEAST BEGINS. AS A RESULT EXPECT THE BAND OF
RAIN TO ERODE FROM THE NORTHEAST AND ALSO DIMINISH AS THE FORCING WEAKENS.
STILL HIGH 850 MB RH SO CLOUDS WILL PERSIST THIS AFTERNOON.
&&
.AVIATION/18Z TAFS/...
MVFR/IFR CIGS MAINLY SOUTHWEST OF MADISON..AND IN THE MODERATE
RAIN BAND NORTH OF MADISON. ELSEWHERE MAINLY VFR CIGS BUT SCATTERED
8 HUNDRED TO 15 HUNDRED FOOT STRATOFRACTUS CLOUDS ARE EXPECTED TO
INCREASE A BIT BRINGING MORE MVFR/IFR CIGS THIS AFTERNOON.
BAND OF RAIN IS EXPECTED TO DIMINISH THIS AFTERNOON AND DRYING
FROM THE NORTHEAST WILL INCREASE TONIGHT AS THE HIGH PRESSURE
CENTERED OVER HUDSON BAY RE-ESTABLISHES ITSELF OVER THE GREAT
LAKES ON SUNDAY.
HOWEVER AREAS SOUTHWEST OF MADISON WILL REMAIN MOIST AND MVFR/IFR
CIGS WILL LINGER OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 334 AM CDT SAT APR 28 2012/
SHORT TERM....TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
LINGERING DRY AIR OVER SRN WI RESULTING IN EVAPORATIVE COOLING AND
AREAS OF SLEET AND EVEN SOME SNOWFLAKES MIXED IN WITH THE LIGHT RAIN
EARLY THIS MORNING. LATEST RUC SOUNDINGS SHOW WET BULB ZERO
REMAINING NEAR OR SLIGHTLY BELOW FREEZING FOR A TIME EARLY THIS
MORNING UNTIL SATURATION OCCURS BETWEEN 10Z AND 15Z. BURST OF
STRONG Q-VECTOR CONVERGENCE AND IMPRESSIVE FN VECTOR RESPONSE TO
FRONTOGENESIS PUSHES IN DURING THIS TIME AS LOW LEVEL SATURATION
OCCURS. SFC TEMPS SHOULD REMAIN ABV FREEZING AS PRECIP SPREADS OVER
THE AREA...BUT NOT IMPOSSIBLE A BURST OF SLEET OR SNOW RESULTS IN
SOME MINOR ACCUMULATION ON GRASS EARLY THIS MRNG. WL NEED TO WATCH
THIS CLOSELY AND ISSUE FREQUENT SHORT TERM FORECASTS.
OTHERWISE...LOW LEVELS EXPECTED TO WARM AND SATURATE THIS MRNG AS
STRONG FORCING ASSOCIATED WITH VIGOROUS MID LEVEL SHORT WAVE OVER
IOWA PUSHES INTO SOUTHERN WI. IMPRESSIVE FN VECTOR RESPONSE TO
LAYER FRONTOGENESIS THIS MRNG WITH 10 TO 20 UNITS OF Q-VECTOR
CONVERGENCE. SHORT WAVE LOSES ITS VIGOR LATE THIS MRNG AND AFTN AS
IT RUNS INTO BUILDING MID LEVEL HIGH PRESSURE OVER THE WESTERN
GTLAKES AND THE CONTINUOUS FEED OF DRIER AIR. LINGERING WEAKENING
FORCING AND DEFORMATION WL RESULT IN AREAS OF -RA CONTINUING INTO
THE AFTN...BUT INTENSITY AND SPACIAL COVERAGE SHOULD BE SLOWLY
DIMINISHING. GRADUAL CLEARING IN THE NORTHERN CWA TONIGHT WL ALLOW
TEMPS TO FALL INTO THE LOW 30S WITH FROST POSSIBLE LATE.
LONG TERM...SUNDAY...FORECAST CONFIDENCE HIGH.
MODELS IN GOOD AGREEMENT THAT SUFACE HIGH CENTERED NORTH OF GREAT
LAKES SUNDAY WILL DOMINATE THE REGION AND LIMIT CLOUDS AND KEEP
REGION DRY. LAKE MICHIGAN WATER TEMPS ARE MIDDLE TO UPPER 40S SO
EAST WINDS OFF LAKE MICHIGAN SUNDAY AND WILL KEEP SUNDAY HIGH TEMPS
NEAR 50 ALONG LAKESHORE TO UPPER 50S IN SOUTHCENTRAL AND SOUTHWEST
WISCONSIN.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FORCAST CONFIDENCE HIGH FOR
PRECIP CHANCES AND TYPE...MEDIUM FOR TIMING START AND END TIMES.
MODELS IN GOOD AGREEMENT MOVING SURFACE HIGH EAST OF THE AREA SUNDAY
NIGHT AND MONDAY WITH SOUTHERLY LOW LEVEL RETURN FLOW AND
APPROACHING UPPER LEVEL TROUGH BRINGING WARMER TEMPERTURES ALONG
WITH MOISTURE AND CLOUDS TO THE REGION SUNDAY NIGHT AND MONDAY. SOME
DISAGREEMENT ON TIMING OF START AND END OF PRECIPITATION...WITH NAM
SLOWER THAN EUROPEAN UKMET AND GFS WHICH START PRECIPITATION IN
SOUTHWEST WISCONSIN AROUND SUNDOWN SUNDAY AND MOVE AND INTENSIFY IT
ACROSS MOST OF THE STATE BY SUNRISE MONDAY AND CONINUE IT THROUGH
THE DAY MONDAY. PRECIPITATION DISSIPATES WEST TO EAST MONDAY NIGHT.
TEMPERATURES WARM ENOUGH THAT ALL PRECIPITATION WILL BE LIQUID WITH
HIGHEST PRECIPITATION AMOUNTS SOUTH OF I-94.
TUESDAY THROUGH SATURDAY. FORECAST CONFIDENCE MEDIUM.
SURFACE LOW OVER DAKOTAS AND MINNESOTA TUESDAY AND WEDNESDAY WILL
KEEP SOUTHERLY WINDS AND WARM TEMPERATURES...WITH HIGHS NEAR 70
TUESDAY AND MID 70S WEDNESDAY AND THURSDAY. UPPER TROUGH WEST OF THE
REGION WILL ALLOW SOUTHWEST FLOW WITH UPPER LEVEL DISTURBANCES
MOVING IN SOUTHWEST FLOW ACROSS THE REGION AND BRINGING CHANCE OF
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. BEST CHANCE OF
STRONG THUNDERSTORMS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH BEST
CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WHEN CAPE...BULK SHEAR
AND OTHER SEVERE INDICIES ARE AT A MAXIMUM FOR THE ENTIRE WEEK.
ADDITIONAL UPPER SHORT WAVES WILL CONTINUE UNSETTLED WEATHER THROUGH
SATURDAY WHEN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE REGION.
AVIATION/12Z TAFS/...NOT IMPOSSIBLE A BURST OF MODERATE SLEET OR
EVEN SNOW COULD BRIEFLY AFFECT TAF SITES EARLY THIS MORNING AS
STRONG FORCING WITH APPROACHING SHORT WAVE MOVES INTO SOUTHERN WI.
LINGERING DRY AIR RESULTING IN EVAPORATIVE COOLING AND MIX OF
PRECIP...SHOULD MOISTEN UP THIS MRNG...WITH PERIODS OF RA EXPCD
FOR MOST OF THE DAY. ONLY A LITTLE DRIZZLE POSSIBLE FOR A TIME
THIS EVENING DUE TO LINGERING MID-LEVEL DEFORMATION. CIGS SHOULD
LOWER TO IFR AND POSSIBLY LWR LATER THIS MORNING...GRADUALLY
LIFTING LATE TODAY AND TNGT.
MARINE...PRESSURE GRADIENT CONTINUES TO TIGHTEN OVER SOUTHERN LAKE
MI THIS MORNING AS LOW PRESSURE MOVES ACROSS NRN MO. GRADIENT WL
BEGIN TO RELAX LATER TODAY AND TONIGHT AS LOW WEAKENS TO THE
SOUTH...AND HIGH PRESSURE RIDGE BUILDS IN FROM THE NORTH. LOW LEVEL
UNSTABLE AIR MASS OVER THE LAKE SHOULD RESULT IN WINDS UP TO 30KTS
IN SRN MARINE ZONE...TRAILING OFF THE NORTH. WL CONTINUE SMALL
CRAFT ADVISORY FOR SRN 3 ZONES FOR TODAY AND TNGT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LMZ644>646.
&&
$$
UPDATE...HENTZ
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...SLB