Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/08/12
AREA FORECAST DISCUSSION...CORRECTED
NWS PHOENIX AZ
835 PM MST FRI SEP 7 2012
.SYNOPSIS...
A VERY MOIST AND UNSTABLE MONSOON AIRMASS WILL CONTINUE TO COVER THE
REGION THROUGH EARLY NEXT WEEK...AND LEAD TO A CHANCE OF SHOWERS AND
THUNDERSTORMS EACH DAY. THUNDERSTORM COVERAGE AND INTENSITY WILL
VARY FROM DAY TO DAY...WITH SOMEWHAT BETTER CHANCES EXPECTED OVER
THE WEEKEND AND INTO NEXT MONDAY. HIGH TEMPERATURES WILL REMAIN
BELOW SEASONAL NORMALS EACH DAY GIVEN THE HIGH MOISTURE CONTENT IN
THE ATMOSPHERE.
&&
.PREV DISCUSSION...
ISSUED AT 400 PM MST FRI SEP 7 2012
RADAR CURRENTLY SHOWS SOME ISOLATED LIGHT SHOWERS MOVING NORTHEAST
TO SOUTHWEST ACROSS WESTERN MARICOPA COUNTY INTO YUMA COUNTY. MORE
INTENSE STORMS TRACKED ACROSS NORTHERN LA PAZ AND SOUTHERN RIVERSIDE
COUNTY EARLIER IN THE EVENING PRODUCING AREAS OF VERY HEAVY
RAINFALL. MOST ACTIVITY THOUGH HAD DIED OUT BY 5 PM.
MODELS INDICATE THE VORT MAX THAT WAS LOCATED OVER SOUTHERN
ARIZONA...HELPING TO PROVIDE THE DYNAMICS FOR ACTIVITY EARLIER
TODAY...IS DRIFTING TO THE SOUTH. FLOW IS BECOMING MORE
UNIDIRECTIONAL AS DISTURBANCE DRIFTS TO THE SOUTH...REDUCING THE LOW
LEVEL CONVERGENCE AND UPPER LEVEL DIVERGENCE THAT WERE AIDING STORM
DEVELOPMENT.
MESOSCALE MODELS DID NOT HANDLE DEVELOPMENT OF CONVECTION VERY WELL
TODAY AND EARLY EVENING. OF ALL MODELS THOUGH THE NAM SEEMED TO DO
THE BEST IN HANDLING DEVELOPMENT OF ACTIVITY EARLY THIS EVENING. THE
NAM/S 00Z MODEL SOUNDING FOR PHOENIX ALSO INITIALIZED PRETTY WELL
WITH THE OBSERVED SOUNDING...CAPTURING THE MOISTURE AND LOW LEVEL
INVERSION FAIRLY WELL. BOTH THE NAM AND OBSERVED SOUNDING WERE
SHOWING PWAT IN EXCESS OF 1.8 INCHES.
THE NEAR TERM FORECAST BY THE NAM KEEPS THINGS FAIRLY QUIET OVER
NIGHT. THIS SEEMS REASONABLE...THOUGH THERE STILL IS ENOUGH
INSTABILITY AND ABUNDANT MOISTURE AROUND TO WARRANT KEEPING SOME
POPS IN THE FORECAST.
FOR TOMORROW...THE NAM SHOWS MONSOONAL STORMS REARING THEIR HEAD
AGAIN BY MID-DAY...TRIGGERED IN PART BY THE LOW TO OUR SOUTH WHICH
WILL BE SPINNING SOME ADDITIONAL SHORT WAVES AROUND ITS NORTHERN
PERIPHERY.
FORECAST PACKAGE FOR THE MOST PART WAS ON TRACK. MADE SOME MINOR
ADJUSTMENTS TO TEMPERATURE AND DEWPOINT GRIDS.
&&
.PREV DISCUSSION...
ISSUED AT 400 PM MST FRI SEP 7 2012
BROAD AREA OF LOW PRESSURE CONTINUES TO DRIFT INTO SOUTHERN AZ WITH
SEVERAL REMNANT MCVS NOTED ON VISIBLE SATELLITE AND WV IMAGERY. THIS
SYSTEM HAS SOME TROPICAL CHARACTERISTICS IN THAT IT IS A SYMMETRIC
LOW WITH A SHALLOW WARM CORE AND SHEARED OUTFLOW.
FOCUS HAS SHIFTED TO WESTERN AZ AND SE CA...WHERE THE NORTHEAST FLOW
HAS INCREASED BETWEEN THE SOUTHERN AZ VORT MAX AND A DEVELOPING
MID-LEVEL ANTICYCLONE NEAR SAN DIEGO. DCAPES ARE ALSO QUITE HIGH AND
THE STRONGEST STORMS HAVE THE POTENTIAL TO PRODUCE SEVERE WIND GUSTS
AND LOCALIZED TORRENTIAL RAIN. FURTHER EAST...THE ATMOSPHERE REMAINS
EXCEPTIONALLY MOIST AND GIVEN THE INCREASING SOLAR INSOLATION AND
SUBSEQUENT CAPE FROM CASA GRANDE TO GLOBE...SCATTERED CONVECTION HAS
THE POTENTIAL TO REDEVELOP LATE THIS AFTERNOON AND THIS EVENING.
LATEST MESOANALYSIS ALSO INDICATES THERE IS LITTLE CONVECTIVE
INHIBITION IN THESE AREAS. NON-HYDROSTATIC MESOSCALE MODELS
INCLUDING THE HRRR CONTINUE TO HAVE A DIFFICULT TIME INITIALIZING
THE RAINFALL FROM THIS MORNING AND THE FORECAST IS LARGELY WEIGHTED
TOWARDS THE GFS/ECMWF/SREF.
THE AFOREMENTIONED LOW IS EXPECTED TO MEANDER SLOWLY SOUTHWESTWARD
SATURDAY AS THE ANTICYCLONE NEAR SAN DIEGO LIFTS INTO NORTHERN AZ.
THIS WILL PRODUCE A MOIST EASTERLY FLOW IN THE MID-LEVELS AND POPS
HAVE BEEN INCREASED AS FAR WEST AS JTNP. DESPITE THE DROP IN
PRECIPITABLE WATER...STORMS AGAIN WILL BE CAPABLE OF PRODUCING HEAVY
RAINFALL AND LOCALIZED FLOODING. A FLASH FLOOD WATCH MAY ULTIMATELY
BE NEEDED FOR PORTIONS OF THE FORECAST AREA. MORE OF THE SAME FOR
SUNDAY AS THE LOW MOVES INTO SOUTHERN CA...BUT STILL YIELDING A
MOIST SOUTHERLY FLOW WITH WELL ABOVE AVERAGE CHANCES FOR HEAVY RAIN
AND THUNDERSTORMS.
WESTERLY FLOW ALOFT BEGINS TO TAKE SHAPE ON MONDAY AS THE UPPER
LEVEL PVD MOVES THROUGH SOUTHERN ARIZONA INTO NEW MEXICO. MOISTURE
SHOULD WORK ITS WAY BACK INTO EASTERN ARIZONA AND ALL LOCATIONS
SHOULD SEE A DECENT CHANCE OF SHOWERS AND THUNDERSTORMS. MONDAY
COULD BE THE BEST CHANCE AREA-WIDE FOR PRECIP GIVEN FAVORABLE UPPER
LEVEL SUPPORT AND POPS WERE INCREASED INTO THE 40-50 PERCENT RANGE
TO REFLECT THIS. FOLLOWING THE TROUGH...A GRADUAL DECREASE IN
MOISTURE AND INSTABILITY WILL GREATLY REDUCE THE AMOUNT OF STORMS
FROM TUESDAY ONWARD. COULD SEE A FEW RENEGADE STORMS EAST OF PHOENIX
ON TUESDAY WHERE SOME MOISTURE AND INSTABILITY WILL RESIDE /PER THE
SLOWER ECMWF SOLUTION/ BUT WESTERLY FLOW WILL STEER THESE STORMS
AWAY FROM THE DESERTS. 1000-700MB MOISTURE DROPS ALL THE WAY DOWN TO
AROUND 6 G/KG ON WEDNESDAY WITH BARELY ANY INSTABILITY TO SPEAK OF
ANYWHERE IN THE STATE. MAY STRUGGLE TO EVEN GET AFTERNOON CU LATE
NEXT WEEK AND POPS WERE REDUCED WELL BELOW CLIMO FOR THE END OF THE
FORECAST PERIOD.
WITH ELEVATED MOISTURE...TEMPS SHOULD STAY AOB NORMAL THROUGH AT
LEAST THE MIDDLE OF NEXT WEEK. TEMPS WILL CLIMB SLIGHTLY FROM THE
MIDDLE OF NEXT WEEK ONWARD IN RESPONSE TO DECREASING MOISTURE BUT
STILL IN THE BALLPARK OF NORMAL FOR MID SEPTEMBER.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...MOSTLY
CLOUDY SKIES AND LIGHT AND VARIABLE WINDS WILL REMAIN OVER
SOUTH-CENTRAL ARIZONA THROUGH MID-DAY ON SATURDAY. A FEW ISOLATED
SHOWERS WILL LINGER OVER THE REGION THROUGH EARLY SATURDAY MORNING.
CLOUD BASES WILL BE AOA 6 KFT.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...PARTLY TO
MOSTLY CLOUDY SKIES WILL REMAIN OVER SOUTHEAST CA AND SOUTHWEST AZ
THROUGH MID-DAY ON SATURDAY. CLOUD BASES WILL BE AOA 10 KFT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
LINGERING MOISTURE WILL MAINTAIN AN ELEVATED CHANCE OF THUNDERSTORMS
FOR EARLY NEXT WEEK. DEEPER WESTERLY FLOW WILL LEAD TO A DOWNTREND
IN ATMOSPHERIC MOISTURE BEGINNING TUESDAY. THUS...HUMIDITIES AND
STORM CHANCES WILL DECLINE FROM WEST TO EAST. THERE WILL BE ONLY A
SLIGHT CHANCE OF THUNDERSTORMS LEFT OVER THE HIGHER TERRAIN OF
SOUTH-CENTRAL ARIZONA ON WEDNESDAY AND THURSDAY. MINIMUM HUMIDITIES
WILL DROP INTO THE UPPER TEENS OVER SOUTHEAST CALIFORNIA BY
THURSDAY. APART FROM THUNDERSTORM OUTFLOWS...NO STRONG WINDS ARE
ANTICIPATED. AFTERNOON WINDS ARE EXPECTED TO FAVOR SOUTHWEST AND
WESTERLY DIRECTIONS FOR MOST AREAS BEGINNING TUESDAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...MCLANE/HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...MCLANE
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
400 PM MST FRI SEP 7 2012
.SYNOPSIS...
A VERY MOIST AND UNSTABLE MONSOON AIRMASS WILL CONTINUE TO COVER THE
REGION THROUGH EARLY NEXT WEEK...AND LEAD TO A CHANCE OF SHOWERS AND
THUNDERSTORMS EACH DAY. THUNDERSTORM COVERAGE AND INTENSITY WILL
VARY FROM DAY TO DAY...WITH SOMEWHAT BETTER CHANCES EXPECTED OVER
THE WEEKEND AND INTO NEXT MONDAY. HIGH TEMPERATURES WILL REMAIN
BELOW SEASONAL NORMALS EACH DAY GIVEN THE HIGH MOISTURE CONTENT IN
THE ATMOSPHERE.
&&
.DISCUSSION...
BROAD AREA OF LOW PRESSURE CONTINUES TO DRIFT INTO SOUTHERN AZ WITH
SEVERAL REMNANT MCVS NOTED ON VISIBLE SATELLITE AND WV IMAGERY. THIS
SYSTEM HAS SOME TROPICAL CHARACTERISTICS IN THAT IT IS A SYMMETRIC
LOW WITH A SHALLOW WARM CORE AND SHEARED OUTFLOW.
FOCUS HAS SHIFTED TO WESTERN AZ AND SE CA...WHERE THE NORTHEAST FLOW
HAS INCREASED BETWEEN THE SOUTHERN AZ VORT MAX AND A DEVELOPING
MID-LEVEL ANTICYCLONE NEAR SAN DIEGO. DCAPES ARE ALSO QUITE HIGH AND
THE STRONGEST STORMS HAVE THE POTENTIAL TO PRODUCE SEVERE WIND GUSTS
AND LOCALIZED TORRENTIAL RAIN. FURTHER EAST...THE ATMOSPHERE REMAINS
EXCEPTIONALLY MOIST AND GIVEN THE INCREASING SOLAR INSOLATION AND
SUBSEQUENT CAPE FROM CASA GRANDE TO GLOBE...SCATTERED CONVECTION HAS
THE POTENTIAL TO REDEVELOP LATE THIS AFTERNOON AND THIS EVENING.
LATEST MESOANALYSIS ALSO INDICATES THERE IS LITTLE CONVECTIVE
INHIBITION IN THESE AREAS. NON-HYDROSTATIC MESOSCALE MODELS
INCLUDING THE HRRR CONTINUE TO HAVE A DIFFICULT TIME INITIALIZING
THE RAINFALL FROM THIS MORNING AND THE FORECAST IS LARGELY WEIGHTED
TOWARDS THE GFS/ECMWF/SREF.
THE AFOREMENTIONED LOW IS EXPECTED TO MEANDER SLOWLY SOUTHWESTWARD
SATURDAY AS THE ANTICYCLONE NEAR SAN DIEGO LIFTS INTO NORTHERN AZ.
THIS WILL PRODUCE A MOIST EASTERLY FLOW IN THE MID-LEVELS AND POPS
HAVE BEEN INCREASED AS FAR WEST AS JTNP. DESPITE THE DROP IN
PRECIPITABLE WATER...STORMS AGAIN WILL BE CAPABLE OF PRODUCING HEAVY
RAINFALL AND LOCALIZED FLOODING. A FLASH FLOOD WATCH MAY ULTIMATELY
BE NEEDED FOR PORTIONS OF THE FORECAST AREA. MORE OF THE SAME FOR
SUNDAY AS THE LOW MOVES INTO SOUTHERN CA...BUT STILL YIELDING A
MOIST SOUTHERLY FLOW WITH WELL ABOVE AVERAGE CHANCES FOR HEAVY RAIN
AND THUNDERSTORMS.
&&
.PREVIOUS DISCUSSION...
WESTERLY FLOW ALOFT BEGINS TO TAKE SHAPE ON MONDAY AS THE UPPER
LEVEL PVD MOVES THROUGH SOUTHERN ARIZONA INTO NEW MEXICO. MOISTURE
SHOULD WORK ITS WAY BACK INTO EASTERN ARIZONA AND ALL LOCATIONS
SHOULD SEE A DECENT CHANCE OF SHOWERS AND THUNDERSTORMS. MONDAY
COULD BE THE BEST CHANCE AREA-WIDE FOR PRECIP GIVEN FAVORABLE UPPER
LEVEL SUPPORT AND POPS WERE INCREASED INTO THE 40-50 PERCENT RANGE
TO REFLECT THIS. FOLLOWING THE TROUGH...A GRADUAL DECREASE IN
MOISTURE AND INSTABILITY WILL GREATLY REDUCE THE AMOUNT OF STORMS
FROM TUESDAY ONWARD. COULD SEE A FEW RENEGADE STORMS EAST OF PHOENIX
ON TUESDAY WHERE SOME MOISTURE AND INSTABILITY WILL RESIDE /PER THE
SLOWER ECMWF SOLUTION/ BUT WESTERLY FLOW WILL STEER THESE STORMS
AWAY FROM THE DESERTS. 1000-700MB MOISTURE DROPS ALL THE WAY DOWN TO
AROUND 6 G/KG ON WEDNESDAY WITH BARELY ANY INSTABILITY TO SPEAK OF
ANYWHERE IN THE STATE. MAY STRUGGLE TO EVEN GET AFTERNOON CU LATE
NEXT WEEK AND POPS WERE REDUCED WELL BELOW CLIMO FOR THE END OF THE
FORECAST PERIOD.
WITH ELEVATED MOISTURE...TEMPS SHOULD STAY AOB NORMAL THROUGH AT
LEAST THE MIDDLE OF NEXT WEEK. TEMPS WILL CLIMB SLIGHTLY FROM THE
MIDDLE OF NEXT WEEK ONWARD IN RESPONSE TO DECREASING MOISTURE BUT
STILL IN THE BALLPARK OF NORMAL FOR MID SEPTEMBER.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...A WEAK
WEATHER DISTURBANCE ALONG WITH ABUNDANT MOISTURE OVER THE SOUTHERN
HALF OF ARIZONA WILL LEAD TO SCATTERED SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND INTO THE EVENING HOURS. EXPECT WIDESPREAD CLOUD
DECKS GENERALLY AT OR ABOVE 8KFT WITH CIGS AS LOW AS 5KFT IN HEAVIER
SHOWERS/THUNDERSTORMS. STRONGER STORMS HAVE THE POTENTIAL TO
PRODUCE GUSTY OUTFLOW WINDS UP TO 30KT AND REDUCE VISIBILITIES TO
AROUND 4SM IN HEAVY RAIN.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
ANTICIPATE WIDELY SCATTERED SHOWERS AND THUNDERSTORMS VICINITY KBLH
AFTER 22Z. PROBABILITY LOW AT KIPL...SO NOT INTRODUCING WEATHER IN
THE KIPL TAF AT THIS TIME. SCT-BKN CLOUD DECKS GENERALLY AT OR ABOVE
12KFT...WITH CIGS LOWERING TO 5KFT IN HEAVIER SHOWERS/THUNDERSTORMS.
REDUCED VISIBILITIES DOWN TO 3SM IN HEAVY RAIN WILL BE POSSIBLE WITH
THE STRONGER SHOWERS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
LINGERING MOISTURE WILL MAINTAIN AN ELEVATED CHANCE OF THUNDERSTORMS
FOR EARLY NEXT WEEK. DEEPER WESTERLY FLOW WILL LEAD TO A DOWNTREND
IN ATMOSPHERIC MOISTURE BEGINNING TUESDAY. THUS...HUMIDITIES AND
STORM CHANCES WILL DECLINE FROM WEST TO EAST. THERE WILL BE ONLY A
SLIGHT CHANCE OF THUNDERSTORMS LEFT OVER THE HIGHER TERRAIN OF
SOUTH-CENTRAL ARIZONA ON WEDNESDAY AND THURSDAY. MINIMUM HUMIDITIES
WILL DROP INTO THE UPPER TEENS OVER SOUTHEAST CALIFORNIA BY
THURSDAY. APART FROM THUNDERSTORM OUTFLOWS...NO STRONG WINDS ARE
ANTICIPATED. AFTERNOON WINDS ARE EXPECTED TO FAVOR SOUTHWEST AND
WESTERLY DIRECTIONS FOR MOST AREAS BEGINNING TUESDAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...FLASH FLOOD WATCH UNTIL 7 PM MST THIS EVENING AZZ021.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...MEYERS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST THU SEP 6 2012
.SYNOPSIS...ABUNDANT MOISTURE WILL RESULT IN SCATTERED THUNDERSTORMS
INTO EARLY NEXT WEEK. EXPECT LOCALLY HEAVY RAINFALL WITH THE
STRONGER THUNDERSTORMS. DAYTIME TEMPERATURES WILL GENERALLY BE A FEW
DEGREES BELOW NORMAL.
&&
.DISCUSSION...MOSTLY CLEAR SKIES TO PARTLY CLOUDY SKIES ACROSS SE AZ
AT THIS TIME. DEWPOINTS VALID 16Z RANGED FROM THE 60S-LOWER 70S F...
AND THESE TEMPS WERE NEARLY IDENTICAL TO 24 HOURS AGO. 06/12Z KTWC
SOUNDING TOTAL PRECIP WATER WAS NEAR 1.75 INCHES. BLENDED TOTAL
PRECIP WATER IMAGERY DEPICTED VALUES RANGING FROM 1.50 INCHES NEAR
THE NEW MEXICO BORDER TO 1.85 INCHES ACROSS WRN PIMA COUNTY.
WATER VAPOR IMAGERY INDICATES CYCLONIC CIRCULATION FEATURE MOVING
NEWD ACROSS NERN SONORA. 06/06Z UNIV OF AZ WRF-GFS...06/12Z UNIV OF
AZ WRF-NAM AND 06/11Z RUC HRRR WERE VERY SIMILAR WITH DEPICTING AN
ACTIVE CONVECTIVE PERIOD ACROSS SE AZ FROM THIS AFTERNOON THRU FRI.
INHERITED POPS FOR THIS AFTERNOON AND THIS EVENING SEEM REASONABLE
AS THE AFOREMENTIONED SYNOPTIC-SCALE SYSTEM APPROACHES SE AZ. MAY
STILL ADJUST POPS UPWARD ABOUT 10-20 PERCENT LATER THIS MORNING
AFTER RECEIPT OF THE 06/12Z GFS. THE MAIN THREAT WILL BE LOCALLY
HEAVY RAINFALL AS WELL AS STRONG WIND GUSTS. THE BULK OF CONVECTIVE
ACTIVITY IS EXPECTED TO END LATE TONIGHT.
&&
.PREV DISCUSSION...SCATTERED TYPE POPS EXPECTED AGAIN DURING THE DAY
ON FRIDAY AND ON SATURDAY AS WELL...AS THE REMNANTS OF THE
DISTURBANCE RESIDE OVER SOUTHERN ARIZONA ON FRIDAY AND MOVES TOWARD
SOUTHWEST ARIZONA ON SATURDAY.
THE DISTURBANCE WILL RESIDE OVER SOUTHERN CALIFORNIA OR THE COLORADO
RIVER BASIN ON SUNDAY WITH A RIDGE OF HIGH PRESSURE TO OUR EAST OVER
NEW MEXICO. THIS WILL ALLOW SOUTHERLY FLOW TO CONTINUE TO PUMP
MOISTURE NORTHWARD. THIS PATTERN WILL LIKELY CONTINUE TO PERSISTS
THROUGH EARLY NEXT WEEK FOR ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS EACH AFTERNOON AND EVENING DURING THAT TIME. BY MID
WEEK OR SO...HIGH PRESSURE WILL BUILD FROM THE WEST FOR A
POSSIBILITY THAT SOME DRY AIR MAY INTRUDE FROM THE WEST FOR A
DECREASE IN RAIN CHANCES...BUT ISOLATED IN NATURE.
HIGH TEMPERATURES GENERALLY 2 TO 4 DEGS BELOW NORMAL TODAY THROUGH
SATURDAY...THEN AT OR SLIGHTLY BELOW NORMAL FOR THE REMAINDER OF THE
FORECAST PERIOD. LOWS AROUND 2 TO 4 DEGS ABOVE NORMAL EACH MORNING.
&&
.AVIATION...SCT TO NUMEROUS TSRA/SHRA AFTER 18Z AND CONTINUING INTO
THIS EVENING. WIND GUSTS AROUND 40-45 KTS AND MVFR CIGS/VSBYS WITH
THE STRONGEST TSRA. ISOLD-SCT -TSRA/-SHRA 06Z-12Z FRIDAY.
OTHERWISE...VFR CONDITIONS AND SURFACE WIND MOSTLY LESS THAN 10 KTS
THRU EARLY FRIDAY MORNING OR 07/12Z. AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF THUNDERSTORMS MAINLY DURING THE
AFTERNOON AND EVENING HOURS INTO EARLY NEXT WEEK. EXPECT A GRADUAL
DECREASE IN THUNDERSTORM ACTIVITY BY THE MIDDLE OF NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/TUCSON
BF
PREV DISCUSSION...MOLLERE
AREA FORECAST DISCUSSION
NWS ALBANY NY
511 PM EDT THU SEP 6 2012
.SYNOPSIS...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
PERSIST ACROSS PORTIONS OF THE REGION THIS EVENING...AS ANOTHER WEAK
FRONTAL BOUNDARY CROSSES THE AREA. THE FRONT WILL THEN STALL SOUTH
AND EAST OF THE REGION FRIDAY...BEFORE A STRONGER FRONT APPROACHES
FROM THE WEST LATE SATURDAY BRINGING THE POTENTIAL FOR MORE
WIDESPREAD SHOWERS AND THUNDERSTORMS. MUCH COOLER AIR WILL FILTER
INTO THE REGION IN THE WAKE OF THIS FRONT FOR SUNDAY INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 5 PM EDT...ISOLATED THUNDERSTORMS HAVE AFFECTED PORTIONS OF
THE SOUTHERN ADIRONDACKS...AND HAVE APPROACHED...BUT WEAKENED
BEFORE REACHING THE SCHOHARIE VALLEY. IT APPEARS THAT THE
COMBINATION OF LIMITED HEATING DUE TO PERSISTENT HIGH
CLOUDINESS...AS WELL AS THE FACT THAT MUCH OF OUR REGION WAS
LOCATED WITHIN THE UNFAVORABLE REGION OF A COUPLED JET STRUCTURE
FOR UPWARD MOTION /WITHIN THE RIGHT EXIT REGION OF THE JET MAX
TRANSLATING ACROSS THE EASTERN GREAT LAKES AND WITHIN RIGHT
ENTRANCE REGION OF JET MAX TRANSLATING ACROSS WESTERN NEW ENGLAND
ACCORDING TO THE RUC13 AND GFS-40 300-200 MB WIND ISOTACHS/ HAS
WORKED TO GREATLY SUPPRESS CONVECTION IN OUR REGION. THIS COUPLED
JET STRUCTURE OF THE UNFAVORABLE KIND FOR UPWARD MOTION AND
CONVECTION SHOULD ALSO TRANSLATE FURTHER N AND E OF THE REGION
THIS EVENING...SO CAN NOT COMPLETELY RULE OUT ADDITIONAL ISOLATED
TO PERHAPS SCATTERED CONVECTION DURING THE EVENING...MAINLY ACROSS
NORTHERN AREAS...AND PERHAPS THE EASTERN CATSKILLS AS DOWNWARD
MOTION DECREASES.
THE SURFACE BOUNDARY PARTIALLY RESPONSIBLE FOR TRIGGERING THIS
CONVECTION WILL PASS ACROSS THE REGION LATER THIS EVENING...BEFORE
SLOWING DOWN ACROSS SOUTHERN PORTIONS OF THE REGION LATER TONIGHT.
FOR NOW...WILL TAPER POPS AFTER MIDNIGHT...FROM NW TO SE.
HOWEVER...BOTH THE 12Z NAM AND CMC INDICATE SOME ADDITIONAL
CONVECTIVE POTENTIAL REDEVELOPING BEFORE DAYBREAK ACROSS SOUTHERN
PORTIONS OF THE REGION. FOR NOW...HAVE NOT INCLUDED POPS...BUT
WILL NEED TO WATCH RADAR TRENDS OVERNIGHT AS THIS POSSIBILITY CAN
NOT COMPLETELY BE RULED OUT.
ALTHOUGH THE BOUNDARY LAYER MIXED SIGNIFICANTLY BETTER THAN ON
WED...DECREASING WINDS...AND CLEARING SKIES MAY ALLOW FOR PATCHY
FOG TO DEVELOP AGAIN LATER TONIGHT...ESP IN RIVER VALLEYS...AND
HAVE INCLUDED MENTION IN FORECAST. ASSUMING LITTLE OR NO RAIN
OCCURS...THE EXTENT OF THE FOG AND/OR LOW CLOUDS SHOULD BE LESS
THAN THIS MORNING.
FOR MINS...HAVE SIDED A BIT CLOSER TO THE WARMER MET MOS...WITH
MID 50S TO LOWER 60S IN MOST AREAS...EXCEPT FOR 45-50 ACROSS THE
SOUTHERN ADIRONDACKS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
FRIDAY...THE WEAK BOUNDARY ACROSS SOUTHERN AREAS SHOULD BEGIN
DRIFTING BACK NORTH DURING THE AFTERNOON AND EVENING HOURS. THIS
MAY BE JUST ENOUGH OF A LOW LEVEL TRIGGER TO ALLOW FOR ISOLATED
THUNDERSTORMS TO DEVELOP IN THE AFTERNOON...ESP ACROSS HIGHER
TERRAIN...WHERE SLIGHT CHC POPS ARE INDICATED. HAVE KEPT MOST
AREAS FROM THE CAPITAL REGION N AND W OF ALBANY GENERALLY
DRY. FOR MAX TEMPS...GENERALLY FOLLOWED WITH BLEND OF MAV/MET
MOS...WITH LOWER/MID 80S IN MOST VALLEYS...AND 75-80 ACROSS HIGHER
TERRAIN. DEWPOINTS SHOULD GRADUALLY RISE INTO AND THROUGH THE
LOWER/MID 60S FOR AREAS NEAR AND SOUTH OF THE MOHAWK RIVER BY LATE
IN THE DAY...MAKING FOR MORE HUMID CONDITIONS TO DEVELOP ONCE AGAIN.
FRI NT...INCREASING SOUTH/SOUTHEAST FLOW WILL DEVELOP ACROSS THE
REGION...AND MAY BECOME ENHANCED UP THE HUDSON RIVER VALLEY
BENEATH DEVELOPING INVERSION. SO...EXPECT A BREEZY AND WARM
NIGHT...WITH MINS ONLY FALLING INTO THE 60S IN MOST AREAS...EXCEPT
POSSIBLY SOME 50S ACROSS THE SOUTHERN ADIRONDACKS. MODELS SUGGEST
A LOW LEVEL JET SEGMENT TRANSLATING NNE ACROSS THE SOUTHERN
ADIRONDACKS LATE AT NIGHT...WITH ENHANCED LOW LEVEL CONVERGENCE
ALONG ITS LEADING EDGE. THIS MAY CONTRIBUTE TO INCREASED CHANCES
FOR SHOWERS/TSTMS LATE ACROSS THE WESTERN ADIRONDACKS AND POSSIBLY
MOHAWK VALLEY.
SAT-SAT NT...GUSTY SOUTH WINDS ARE EXPECTED TO DEVELOP AHEAD OF AN
APPROACHING COLD FRONT FROM THE WEST. THIS FRONT IS EXPECTED
SLOWLY APPROACH FROM THE WEST LATE IN THE DAY...ALTHOUGH
DETERMINISTIC MODELS HAVE SLIGHT TIMING DIFFERENCES...WITH
POSSIBLE WEAK WAVES DEVELOPING ALONG THE BOUNDARY. MODELS ALSO
SUGGEST THAT UPPER LEVEL SYSTEM TAKES ON MORE OF A NEGATIVE
TILT...AS ADDITIONAL SHORTWAVE ENERGY DIVES SOUTH FROM CANADA INTO
THE UPPER OHIO VALLEY REGION. THIS SUGGESTS THE POSSIBILITY OF A
NARROW COLD FRONTAL RAINBAND ACCOMPANYING/PRECEDING THE
FRONT...WHICH MAY BE ACCOMPANIED BY A BRIEF PERIOD OF VERY HEAVY
RAIN...AND GUSTY WINDS. ALSO...GIVEN A STRONG LOW LEVEL WIND FIELD
DEVELOPING AHEAD OF THE BOUNDARY...WILL NEED TO WATCH FOR ANY
DISCRETE THUNDERSTORMS THAT DEVELOP AHEAD OF THE FRONTAL
BOUNDARY...AS LOW LEVEL SHEAR WILL BE RATHER HIGH. THE QUESTION AS
TO WHETHER HOW MANY DISCRETE CELLS CAN DEVELOP WILL BE EXTENT OF
PREFRONTAL CLOUD COVER...AS LOW CLOUDS MAY DEVELOP AND MOVE NORTH
WITHIN STRONG SOUTH WIND FLOW. SHOULD LESS CLOUDS/MORE SUN
DEVELOP...AN ENHANCED THREAT FOR STRONG THUNDERSTORMS WILL EXIST.
EXPECT MAX TEMPS TO REACH 80-85 IN VALLEYS...AND 75-80 ACROSS
HIGHER ELEVATIONS. SHOWERS/TSTMS WILL EVENTUALLY DECREASE FROM W
TO E LATER SAT NT AS THE FRONT MOVES E OF THE REGION.
AGAIN...TIMING DIFFS EXIST ON HOW FAST THIS OCCURS...WITH THE BEST
CHANCE FOR RAIN MAINLY THROUGH MIDNIGHT.
SUNDAY-SUNDAY NIGHT...IN THE WAKE OF THE FRONT...MUCH COOLER AIR
WILL FILTER INTO THE REGION ON BRISK WEST WINDS. THE COMBINATION
OF CHILLY AIR PASSING OVER THE MUCH WARMER GREAT LAKES SHOULD LEAD
TO ENHANCED CLOUDS...AND SHOWER POTENTIAL FOR AREAS N AND W OF
ALBANY. IN ADDITION...FORCING FROM A STRONG SHORTWAVE APPROACHING
FROM THE SOUTHWEST MAY FURTHER CONTRIBUTE TO SHOWER DEVELOPMENT
DURING THE DAY...SO WILL KEEP SLIGHT CHC TO LOW CHC POPS THROUGH
SUNDAY EVENING...TAPERING SUN NT. SUNDAY MAXES WILL GENERALLY
REACH 70-75 IN VALLEYS...AND 50S TO LOWER 60S ACROSS HIGHER
TERRAIN ACROSS THE SOUTHERN ADIRONDACKS...AND 65-70 IN WESTERN NEW
ENGLAND. MINS FOR SUN NT SHOULD FALL INTO THE 40S AND LOWER 50S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A RATHER TRANQUIL PERIOD OF WEATHER IS EXPECTED ACROSS THE REGION AS
WE WATCH A DEPARTING UPPER TROUGH TO BE REPLACED BY RIDGING AND
RISING SURFACE PRESSURES THROUGH THE MID WEEK PERIOD. TO ACCOUNT
FOR THE RESIDUAL CYCLONIC FLOW ON MONDAY...WE WILL HOLD ONTO THE
SLIGHT CHANCE POPS ACROSS THE DACKS. OTHERWISE...UNSEASONABLY
COOLER WEATHER TO START THE WEEK AS SINGLE DIGIT 850MB TEMPS WILL
LIKELY HOLD HIGHS INTO THE 60S TO NEAR 70F FOR VALLEY LOCATIONS ON
MONDAY...THEN A GRADUAL WARMING OF THE COLUMN THROUGH THE MID WEEK
PERIOD UNDER A GOOD DEAL OF SUNSHINE WITH HIGHS WELL INTO THE 70S TO
NEAR 80F FOR VALLEY LOCATIONS WEDNESDAY. OVERNIGHT LOWS WILL BE
COOLEST MONDAY NIGHT INTO TUESDAY NIGHT WITH MOSTLY 40S TO NEAR 50F
WITH A GRADUAL WARMING EXPECTED INTO THE MID WEEK PERIOD.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED FOR THE MAJORITY OF THE AFTERNOON AND
EARLY EVENING HOURS. WE CONTINUE TO WATCH AN INCREASING AREA OF
ENHANCED CU ACROSS THE HIGHER TERRAIN OF THE DACKS THAT MIGHT BE THE
BEGINNING STAGES FOR SHOWERS/THUNDERSTORMS. LATEST EXPERIMENTAL
REFLECTIVITIES POINT TOWARD A SCT-BKN LINE OF CONVECTION TO MOVE
INTO THE HUDSON RIVER VALLEY AND WESTERN NEW ENGLAND TOWARD 20Z. WE
WILL PLACE A VCSH AT THIS TIME FOR TAF SITES AND MONITOR/AMEND ONCE
TRENDS HAVE BEEN IDENTIFIED.
ANY CONVECTION SHOULD QUICKLY DISSIPATE THIS EVENING WITH THE
COMBINATION OF THE LOSS OF DAYTIME HEATING AND FRONTAL PASSAGE.
HOWEVER...THIS FRONT BECOMES QUITE DIFFUSE AS IT TRACKS INTO THE
CATSKILLS AND MID HUDSON VALLEY INCLUDING NW CT. MODELS ARE IN
AGREEMENT WITH SOME ENHANCED CU DEVELOPING THAT MAY IMPACT SOUTHERN
LOCATIONS OVERNIGHT. THIS WILL PLAY HAVOC WITH FOG POTENTIAL AND
IMPACTS. FOR NOW...GIVEN CROSS OVER TEMPERATURES ARE AT LEAST
EXPECTED...WE WILL DROP INTO MVFR FOR VIS AND FAVORED LOCATIONS LIKE
KGFL-KPOU INTO IFR THRESHOLDS. THIS LOW STRATUS MAY ALSO IMPACT
KPSF AS WE WILL ALSO INCLUDE IFR CONDITIONS OVERNIGHT.
WINDS WILL BE RATHER LIGHT AND VARIABLE THROUGH THE PERIOD...WITH
MAIN WIND DIRECTION FROM THE SOUTH-SOUTHWEST THROUGH THE PERIOD.
OUTLOOK...
FRI...MAINLY VFR. MVFR/IFR POSSIBLE DUE TO FOG/BR ESPECIALLY AT
KGFL AND KPSF AT NIGHT/EARLY IN THE MORNING.
SAT...RAIN BECOMING LIKELY WITH A CHC OF TSTMS.
SUN...VFR/MVFR. CHC -SHRA.
MON-TUE...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUED ARE EXPECTED THROUGH THE PERIOD. ISOLATED
TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR INTO THIS
EVENING AS ANOTHER WEAK FRONTAL BOUNDARY CROSSES THE AREA. THE
FRONT WILL THEN STALL SOUTH AND EAST OF THE REGION FRIDAY...BEFORE
A STRONGER FRONT APPROACHES FROM THE WEST LATE SATURDAY BRINGING
THE POTENTIAL FOR A WIDESPREAD SOAKING RAINFALL.
&&
.HYDROLOGY...
A WEAK FRONTAL BOUNDARY WILL BRING ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS THIS EVENING. MOST AREAS WILL REMAIN DRY...ALTHOUGH
SOME LOCATIONS COULD RECEIVE A QUICK QUARTER TO HALF INCH OF RAIN.
ANY BRIEF...DOWNPOURS COULD LEAD TO TEMPORARY PONDING OF WATER IN
LOW LYING...POOR DRAINAGE AND URBAN AREAS.
A FEW MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ON
FRIDAY WITH THE FRONT LINGERING ACROSS THE SOUTHEAST PORTION OF THE
HSA. A MORE WIDESPREAD RAINFALL COULD OCCUR THIS WEEKEND...AS A
FRONTAL BOUNDARY AND LOW PRESSURE SYSTEM APPROACH FROM THE MIDWEST
AND OHIO VALLEY. AT THIS TIME THE SPEED OF MOVEMENT OF THIS SYSTEM
IS UNCERTAIN...WHICH WILL HAVE AN IMPACT ON RAINFALL AMOUNTS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/JPV
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...BGM
AVIATION...BGM
FIRE WEATHER...KL
HYDROLOGY...KL/JPV
AREA FORECAST DISCUSSION
NWS ALBANY NY
927 AM EDT THU SEP 6 2012
.SYNOPSIS...
DRY WEATHER IS EXPECTED TO CONTINUE THROUGH AT LEAST THE FIRST HALF
OF THE DAY...AS A WEAK RIDGE OF HIGH PRESSURE DRIFTS EASTWARD ACROSS
THE REGION. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON AND MAY PERSIST INTO TONIGHT AS ANOTHER WEAK
FRONTAL BOUNDARY CROSSES THE AREA. THE FRONT WILL THEN STALL SOUTH
AND EAST OF THE REGION FRIDAY...BEFORE A STRONGER FRONT APPROACHES
FROM THE WEST LATE SATURDAY BRINGING THE POTENTIAL FOR RAIN.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 915 AM...AREAS OF DENSE FOG CONTINUE TO LIFT WITH RAPID
IMPROVEMENTS IN THE VISIBILITY UNDERWAY. THEREFORE...WE HAVE
REMOVED MENTION OF FOG FROM THE GRIDS/FORECAST. 1KM VISIBLE
IMAGERY THIS MORNING SUGGESTS AMPLE BREAKS IN THE CLOUDS ACROSS
THE DACKS...WESTERN MOHAWK VALLEY AND INTO CENTRAL NY. WITHIN THIS
REGION OF INSOLATION...TEMPERATURES ARE RESPONDING WITH LOWER 70S
QUITE COMMON AND THIS TREND OF PARTIAL SUNSHINE AND WARMING TEMPS
WILL SPREAD EAST THROUGH THIS MORNING. THEN OUR ATTENTION BECOMES
A FOCUS FOR CONVECTION THIS AFTERNOON. THIS MORNINGS 12Z SOUNDINGS
REVEALS RATHER STEEP MID LEVEL LAPSE RATES AHEAD OF WEAKENING COLD
FRONT CROSSING SOUTHWEST ONTARIO AND INTO WESTERN LAKE ERIE. H2O
VAPOR IMAGERY DOES SUGGEST THE MAIN MID LEVEL IMPULSE WAS JUST
EAST OF THE HUDSON RIVER VALLEY. SO THERE WILL BE A DISCONNECT
BETWEEN THE SURFACE FRONT AND UPPER LEVEL IMPULSE.
HOWEVER...LATEST FORECAST HRRR AND SPC WRF REFLECTIVITYS SUGGEST
A SCT-BKN LINE OF CONVECTION TO DEVELOP ALONG EITHER THE FRONTAL
BOUNDARY AND/OR LAKE BREEZE TRACKING EASTWARD THROUGH THE
AFTERNOON. FORECAST SBCAPES ARE AT OR GREAT THAN 1000 J/KG WITH
FORECAST MID LEVEL LAPSE RATES IN THE 6.5 C/KM RANGE. SO THERE IS
A POTENTIAL FOR A COUPLE OF THESE CELLS TO BECOME A LITTLE MORE
ROBUST BUT SEVERE WEATHER THRESHOLDS ARE EXPECTED TO REMAIN JUST
BELOW. PER SPC SWODY1...WE WILL REMAIN WITHIN THE 5% CONTOUR WHICH
MAINLY ENCOMPASSES UPSTATE NY.
LATEST LAV/LAMP AND THOSE 12Z SOUNDINGS SUGGEST A SLIGHT DOWNWARD
MODIFICATION TO FORECAST HIGH TEMPERATURES. DEWPOINTS ALSO REQUIRE
SLIGHT MODIFICATIONS THIS MORNING WITH SLIGHTLY LOWER
VALUES...THEN A RECOVERY EXPECTED WITH SOME MOISTURE POOLING ALONG
AND AHEAD OF THE APPROACHING FRONT.
OVERALL...TEMPS TODAY ARE EXPECTED TO TOP OUT CLOSE TO 10 DEGREES
ABOVE NORMAL FOR THIS TIME OF YEAR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
CHANCES FOR CONVECTION SHOULD DECREASE AFTER DARK DUE TO LOSS OF
DAYTIME HEATING AND LACK OF SIGNIFICANT FORCING. THE AFOREMENTIONED
WEAK FRONT WILL STALL SOMEWHERE NEAR THE SOUTHERN PORTION OF THE
FORECAST AREA AND BECOME SOMEWHAT DIFFUSE OVERNIGHT. WE SHOULD GET A
QUIET PERIOD FROM OVERNIGHT INTO EARLY FRIDAY MORNING. ON
FRIDAY...THE FRONT WILL STILL BE IN THE VICINITY OF SOUTHERN AREAS
AND COULD PROVIDE A TRIGGER FOR A FEW SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON. FORCING AGAIN VERY
WEAK...SO CANNOT JUSTIFY GOING WITH MORE THAN ISOLATED POPS.
INSTABILITY COULD BE SUFFICIENT FOR A FEW STRONGER STORMS...BUT FEEL
THE NAM IS OVERDONE WITH CAPE MAGNITUDE AS SURFACE DEWPOINTS SHOULD
BE LOWER ON FRIDAY THAN THURSDAY.
FRIDAY NIGHT SOUTHERLY FLOW WILL START TO INCREASE...AS A POTENT
UPPER LEVEL TROUGH DIGS FROM SOUTHERN CANADA INTO THE GREAT
LAKES...SPAWNING A POTENTIAL WAVE OR MULTIPLE WAVES OF LOW PRESSURE
ALONG THE ASSOCIATED COLD FRONT AT THE SURFACE IN THE LOWER GREAT
LAKES/OHIO REGION. THE JET ENERGY AND DYNAMICS WITH THIS TROUGH ARE
STRONGER THAN WE HAVE SEEN FROM A SYSTEM IN QUITE SOME TIME. AS THE
UPPER LEVEL PATTEN AMPLIFIES FRIDAY NIGHT...SOUTHERLY FLOW ALOFT
WILL INCREASE TO AROUND 35-50 KT AT 850MB. SOME UPSLOPE SHOWERS MAY
DEVELOP BY EARLY SATURDAY MORNING OVER FAVORED SOUTHERN/WESTERN
ADIRONDACKS. IT WILL BE A MILD NIGHT...WITH A PERSISTENT SOUTHERLY
BREEZE ACROSS THE HIGHER TERRAIN AND IN FAVORED NORTH-SOUTH ORIENTED
VALLEYS.
SHOWERS WILL INCREASE IN COVERAGE SATURDAY MORNING MAINLY ACROSS
WESTERN PORTIONS OF THE AREA...BUT WILL INITIALLY HAVE A DIFFICULT
TIME TRANSLATING EASTWARD AS THE UPPER FLOW PATTERN CONTINUES TO
AMPLIFY. THE SPEED OF PROGRESSION OF THE SURFACE COLD FRONT AND
ASSOCIATED RAIN INTO THE REGION IS STILL SOMEWHAT IN QUESTION DUE TO
POTENTIAL SURFACE WAVE DEVELOPMENT ALONG THE FRONT THAT MAY DELAY
TIMING. MOST SOURCES OF GUIDANCE INDICATING THE UPPER JET ENERGY
WILL LIFT NORTHWARD INTO ONTARIO/QUEBEC AND THUS WOULD ALLOW FOR A
FAIRLY QUICK PROPAGATION OF THE COLD FRONT THROUGH OUR AREA
SATURDAY AFTERNOON AND NIGHT.
SO IT SEEMS LIKE OUR ENTIRE AREA COULD ACTUALLY RECEIVE A GOOD
SOAKING RAINFALL SATURDAY AFTERNOON/EVENING. THERE IS A LOW
PROBABILITY OF SOME THUNDERSTORMS PRODUCING STRONG WINDS...AS MODELS
SHOWING SURFACE BASED CAPE DEVELOPING AHEAD OF THE FRONT ALTHOUGH
THIS IS A CONDITIONAL THREAT THAT DEPENDS ON DEGREE OF HEATING THAT
OCCURS AHEAD OF THE FRONT. WITH THE WIND FIELD ALOFT AND LOW AND
DEEP LAYER WIND SHEAR BEING SO STRONG...IF CONVECTION DEVELOPS SOME
LINEAR SEGMENTS OR BOWS MAY FORM AND PRODUCE DAMAGING WINDS. AGAIN
THIS SCENARIO IS MUDDLED RIGHT NOW BUT BEARS WATCHING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A STRONG UPPER LEVEL TROUGH AND ASSOCIATED LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE REGION SATURDAY NIGHT. THE MODEL GUIDANCE DIFFERS
ON THE AMPLITUDE OF THE UPPER TROUGH AND THE TIMING OF THE COLD
FRONT THROUGH THE REGION. AS MENTIONED IN THE SHORT TERM DISCUSSION
THERE IS THE POTENTIAL FOR THE DEVELOPMENT OF A SURFACE WAVE ALONG
THE FRONT WHICH WOULD SLOW THE FRONTS PROGRESS. HAVE CONTINUED THE
LIKELY POPS FROM SATURDAY AFTERNOON THROUGH MUCH OF SATURDAY NIGHT.
ALSO HAVE KEEP CHANCE POPS IN FOR SUNDAY AS THE UPPER TROUGH SWINGS
THROUGH. THERE IS MODEL AGREEMENT THAT RIDGING WILL BUILD IN BEHIND
THIS SYSTEM AT THE SURFACE AND ALOFT BRINGING FAIR AND COOL...AUTUMN
WEATHER TO THE REGION THROUGH MID WEEK.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
HAVE LIFR CONDITIONS AT TAF SITES DUE TO RADIATIONAL FOG. AN
IMPROVEMENT TO VFR IS EXPECTED BY MID MORNING WITH VFR CONDITIONS
CONTINUING INTO THE EVENING. THERE IS A SLIGHT CHANCE FOR CONVECTION
THIS AFTERNOON AS A WEAK FRONTAL BOUNDARY CROSSES THE
REGION...HOWEVER THE THREAT IS TOO LOW TO INCLUDE IN THE TAFS.
RADIATIONAL FOG IS EXPECTED TO DEVELOP AGAIN TONIGHT RESULTING IN
MVFR AND IFR CONDITIONS.
LIGHT SOUTH-SOUTHWEST WINDS WILL DEVELOP THIS MORNING WITH WINDS
DIMINISHING THURSDAY EVENING.
OUTLOOK...
FRI...MAINLY VFR. MVFR/IFR POSSIBLE DUE TO FOG/BR ESPECIALLY AT
KGFL AND KPSF AT NIGHT/EARLY IN THE MORNING.
SAT...RAIN BECOMING LIKELY WITH A SLIGHT CHC TSTMS.
SUN...VFR/MVFR. CHC -SHRA. MON...VFR. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUED ARE EXPECTED THROUGH THE PERIOD. DRY
WEATHER IS EXPECTED TO CONTINUE THROUGH AT LEAST THE FIRST HALF
OF THE DAY...AS A WEAK RIDGE OF HIGH PRESSURE DRIFTS EASTWARD ACROSS
THE REGION. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP THIS AFTERNOON AND MAY PERSIST INTO TONIGHT AS ANOTHER WEAK
FRONTAL BOUNDARY CROSSES THE AREA. THE FRONT WILL THEN STALL SOUTH
AND EAST OF THE REGION FRIDAY...BEFORE A STRONGER FRONT APPROACHES
FROM THE WEST LATE SATURDAY BRINGING THE POTENTIAL FOR A WIDESPREAD
SOAKING RAINFALL.
&&
.HYDROLOGY...
A WEAK FRONTAL BOUNDARY WILL BRING ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON INTO TONIGHT. MOST AREAS WILL REMAIN
DRY...ALTHOUGH SOME LOCATIONS COULD RECEIVE A QUICK QUARTER TO HALF
INCH OF RAIN. ANY BRIEF...DOWNPOURS COULD LEAD TO TEMPORARY PONDING
OF WATER IN LOW LYING...POOR DRAINAGE AND URBAN AREAS.
A FEW MORE SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ON
FRIDAY WITH THE FRONT LINGERING ACROSS THE SOUTHEAST PORTION OF THE
HSA. A MORE WIDESPREAD RAINFALL COULD OCCUR THIS WEEKEND...AS A
FRONTAL BOUNDARY AND LOW PRESSURE SYSTEM APPROACH FROM THE MIDWEST
AND OHIO VALLEY. AT THIS TIME THE SPEED OF MOVEMENT OF THIS SYSTEM
IS UNCERTAIN...WHICH WILL HAVE AN IMPACT ON RAINFALL AMOUNTS.
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...
KENX DOPPLER RADAR WILL BE OFFLINE DUE TO A REQUIRED UPGRADE THIS
MORNING WITH A RETURN TO FULL SERVICE EXPECTED BY EARLY AFTERNOON.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...BGM/JPV
SHORT TERM...JPV
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...JPV
HYDROLOGY...JPV
EQUIPMENT...BGM
FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
354 PM EDT Thu Sep 6 2012
.NEAR TERM [Through Tonight]...
Despite the normally favorable Sea Breeze Flow for convection
(with a 1000-700 mb Mean Layer Vector Wind (MLVW) out of the SSE
at 10 to as high as 10 to 15 kts (Type 6 or 7 Regime)), the
showers and storms have not been quite as numerous as earlier
expected. This could be due to some mid-upper level dry air
entrainment from the NNE, as PWATs have fallen from the 2.1"-2.2"
yesterday to around 1.8" this afternoon. Therefore, will plan on
trimming PoPs back a bit for the remainder of the day based on
current Radar and Satellite Trends, as well as the near term fcsts
from the HRRR and Hi-Res WRFs. The favored area thus far has been
the SE FL Big Bend and the Adjacent Coastal Waters, with the
convection over the Panhandle waters dissipating, possibly in
response to the remnants of Isaac pulling moisture off to the SW.
For tonight, PoPs may be a bit tricky over the interior for a few
hours this evening (but generally in the 20-30% range), but should
be able to bump up PoPs to at least 30% over the Coastal Waters
from 06-12 UTC.
&&
.SHORT TERM [Friday Through Sunday]...
The period starts with a north/south split pattern. To the north,
deep low pressure spins over western Quebec with a trough
extending west/southwest through the Northern Rockies. To the
south, deep layer high pressure is centered over the Southern
Plains sprawling the Southwest to the Lower Mississippi Valley. At
the surface, much of the local area is covered by a weak flow
regime under the influence of the subtropical ridge. Along the
western edge of the ridge, a weak area of low pressure spins
across the northern Gulf of Mexico, just south of New Orleans.
Through the weekend, the northern trough will dig through the
Plains and the Mississippi Valley, into the southeast, and
eventually depart the Mid-Atlantic coast. The Gulf low will
meander south of Louisiana until it begins to feel the effects of
the approaching trough/sfc front. This will likely occur some time
on Saturday, when the low will pull northeast across Florida.
Where the low actually traverses the state is still a bit
uncertain, but at this point it appears as though the low will
open up ahead of the sfc front off of the Panhandle coast and move
northeast across north Florida and extreme south Georgia. The bulk
of the rainfall associated with this low will likely remain across
the Gulf and the southeast Big Bend of Florida. In the wake of the
low, a small sliver of dry air will precede the front and result
in a brief period of drying on Saturday night. The front, in the
form of a broken line of widely scattered showers and isolated
thunderstorms will work its way through the local area through the
day on Sunday. There is a slight chance for a severe storm or two
as the front approaches the southeast Big Bend on Sunday
afternoon, where peak heating will result in increased instability
that will couple with 30 to 35 knots of deep layer shear. However,
the severe weather potential is highly dependent on the timing of
the front which is still rather uncertain.
&&
.LONG TERM [Monday through Wednesday]...
The extended period will be dominated by rather nice weather.
Behind the front, don`t expect a marked drop in afternoon
temperatures, however, it appears as though we will dry out rather
nicely for this time of year. This will make the afternoons feel
comfortable, and provide us with cool temperatures in the middle
60s overnight.
&&
.AVIATION [Beginning 20Z Thursday]...
VFR conditions should prevail across the region this afternoon and
evening, although isolated thunderstorms are possible. Showers and
thunderstorms, if they materialize, should end by 00Z. Overnight,
some fog is expected to develop everywhere except ECP. vsbys may dip
to MVFR at sites with fog. At VLD, cigs with fog may dip to IFR.
&&
.MARINE...
The forecast over the Coastal Waters during the next several days
will be highly dependent on the potential development, intensity,
and track of the presently weak low positioned in the northern
Gulf of Mexico. At present, winds and seas are expected to remain
below headline criteria (just below in some cases) for the much of
the remainder of the week and weekend before increasing over by
late Sunday night and early next week as the low moves back to the
northeast or east-northeast. Mariners are urged to keep a close
eye on the forecast over the next several days.
&&
.FIRE WEATHER...
Between the low in the northern Gulf and a cold front forecast to
affect the region Saturday night into Sunday, the area will probably
see rain most of the weekend. From Sunday afternoon and beyond, POPs
drop, however at this time relative humidity values are expected to
remain above criteria values so no fire weather hazards are
anticipated at this time.
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Harrigan
LONG TERM...Harrigan
AVIATION...Moore
MARINE...Gould
FIRE WEATHER...Moore
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
137 AM EDT THU SEP 6 2012
.AVIATION...
COLD FRONT WILL CROSS THE AREA LATER THIS MORNING BUT ABUNDANT
DRY AND STABLE AIR IS PREVENTING ANY SHOWERS FROM DEVELOPING.
CLEAR SKIES AND LIGHT WINDS ARE CAUSING SOME PATCHY FOG TO DEVELOP
ACROSS THE AREA. NOT EXPECTING DENSE FOG BUT MVFR VISIBILITIES
WILL BE POSSIBLE AT KFWA DURING THE NEXT FEW HOURS.
OTHERWISE...VFR CONDITIONS WILL PERSIST TODAY WITH SOME AFTERNOON
CU BASED AROUND 4-5 KFT. NORTHWEST WINDS WILL ALSO INCREASE TODAY
BEHIND THE COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 800 PM EDT WED SEP 5 2012/
UPDATE...
STABLE POST OUTFLW BUBBLE HAS CURTAILED ANY UPSTREAM
CONV DVLPMNT WITHIN RTN LL THETA-E WEDGE ACRS ERN IA/WRN-NRN IL
THIS EVENING AHD OF CDFNT AND DOUBT THAT WILL CHG GOING FORWARD
THROUGH TONIGHT. DROPPED PRIOR TRIMMED POPS FM AFTN ISSUANCE
FORWARD AND MAY DROP ENTIRELY ONCE DVN/ILX 00Z RAOBS ARRIVE. THUS
ITS MORE LIKELY CDFNT COMES THROUGH DRY LTR TONIGHT.
&&
SHORT TERM...
TONIGHT THROUGH THURSDAY NIGHT.
SHORT/SMALL WINDOW OF OPPORTUNITY WRT DESTABILIZATION INADV SFC
FNTL BNDRY ACRS XTRM SERN WI/NRN IL/ERN IA/MO LATE THIS AFTN. OF
NOTE HAS BEEN SPC RAP FAILURE TO ADEQUATELY ASSESS DOWNSTREAM
STABILIZATION AMID WAKE OF MATURE BUBBLE MESOHIGH BEHIND LATE
AM/ERLY AFTN LINEAR CONVECTION THAT NOW ARCHES FM NRN OH TO OH RVR
VALLEY. WHILE EWD ADVANCE OF STEEP 7-5H LAPSE RATES OF 8-9 C/KM
OMINOUS...THE CERTAINLY FAR FROM PRISTINE 0-3KM THERMODYNAMIC
ENVIRON ACRS NERN IL/CWA AMID DENSE CONVECTIVE DEBRIS AND WELL
OVERTURNED ATMOS...WL LKLY QUELL ALL BUT JUST A FLEETING HOPE FOR
ANY FIRM CONVECTIVE MAINTENANCE WITH ERN EXTENT. GIVEN
CONDITIONALITY WRT LATE AFTN INITIATION WITH MODEST LLVL WIND
PROFILE/LWST 100 MB CONVERGENCE AHEAD OF FNT...AND ADDED
CONDITIONALITY FURTHER DOWNSTREAM...HAVE CHOSE LOWER END GUID WITH
NO HIER THAN MID RANGE CHC POPS AFT 02 UTC. SEVERE RISK ALSO
APPEARS TO BE WANING...BUT WL LET HWO CONTINUE TO COVER WITH HIEST
RISKS ACRS SRN CWA/ALONG PROGGED OVERLAP OF SFC CAPE RESERVOIR
AND MODERATE DEEP LYR SHEAR/INCRSG THIS EVE AS 50 KT 5H WNWLY FLOW
ACRS IL/WI SURGES EWD. NIL WX AFTER TONIGHT IN DRYING LLVL ATMOS.
HAVE LWRD TEMPS INVOF KBEH SUBSTANTIALLY TMWR NIGHT IN WEAKENING
SFC FLOW AS 1018 MB PLAINS HIGH SETTLES ACRS SRN GRTLKS...FAVORING
COOL DRAINAGE ALONG LAKESHORE NEAR DAYBREAK FRI.
&&
LONG TERM...
FRIDAY THROUGH WEDNESDAY...A SIGNIFICANT TROF WILL MOVE ACROSS THE
WESTERN GREAT LAKES REGION EARLY IN THE PERIOD. BOTH THE GFS AND THE
ECMWF HAVE ABANDONED THE EARLY CUT OFF LOW SOLUTION FROM MANY
PREVIOUS RUNS IN LIEU OF A MORE PROGRESSIVE OPEN WAVE SOLUTION DUE
TO MORE PHASING WITH THE NORTHERN STREAM AND THE APPROACH OF ANOTHER
UPSTREAM UPPER TROF. HOWEVER...THE ONGOING TIMING OF THE ARRIVAL OF
THE MAIN TROF OVER THE WESTERN GREAT LAKES REGION STILL APPEARS ON
TRACK WITH THE BEST CHANCE FOR RAIN FRIDAY NIGHT. KEPT SHOWERS
LIKELY FRIDAY NIGHT. ADDED A CHANCE FOR THUNDER SOUTHEAST HALF PER
ECMWF WITH EMBEDDED STORMS POSSIBLE GIVEN MOISTURE AND LIFT
AVAILABLE. OTHERWISE...COOLER AND DRY CONDITIONS SUNDAY AND MONDAY
FOLLOWED BY A RETURN TO ABOVE NORMAL TEMPERATURES WEDNESDAY AND THE
UPPER LEVEL RIDGE BUILDS EAST AHEAD OF THE NEXT UPPER LEVEL TROF CAN
BE EXPECTED. THE 500 MB CANADIAN AND GFS ANALOGS ALSO SUPPORT
TEMPERATURES RISING ABOVE NORMAL.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...RIP CURRENT RISK FROM 7 AM CDT THIS MORNING THROUGH THIS EVENING
FOR INZ003.
MI...RIP CURRENT RISK FROM 8 AM EDT THIS MORNING THROUGH THIS EVENING
FOR MIZ077.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...AGD
UPDATE...T
AREA FORECAST DISCUSSION
NWS GOODLAND KS
501 PM MDT FRI SEP 7 2012
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 210 PM MDT FRI SEP 7 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW POSITIVELY TILTED TROUGH
OVER NORTHERN GREAT LAKES WITH AXIS EXTENDING SOUTHWEST ACROSS
CENTRAL NEBRASKA. LARGE SCALE SUBSIDE IS CURRENTLY BUILDING INTO
TRI-STATE AREA AS THIS TROUGH SHIFTS EAST. AT THE SURFACE HIGH
PRESSURE BUILDING INTO THE CWA FROM THE NORTHWEST.
ISOLATED LIGHT SHOWERS/SPRINKLES WILL REMAIN POSSIBLE ACROSS THE NW
THIS AFTERNOON ASSOCIATED WITH COLD POOL ALOFT AND STEEPENING LAPSE
RATES. WE ALSO HAVE SOME WEAK H85-H7 FRONTOGENESIS LINGERING JUST TO
THE NORTHWEST OF THE CWA...RESPONSIBLE FOR CURRENT SHOWER ACTIVITY
OUTSIDE OF CWA. DO NOT ANTICIPATE ANY PRECIP LINGERING PAST SUNSET
WHEN DIURNAL HEATING COMES TO AN END.
COOLER AIR MASS ALREADY IN PLACE AFTER FRONTAL PASSAGE LAST
NIGHT...WITH H85 TEMPS BASED ON THIS MORNINGS 12Z SOUNDING IN THE
12-14C RANGE. WITH CALM WINDS AND CLEARING SKIES I EXPECT OVERNIGHT
TEMPS TO DROP TO THE LOW TO MID 40S ACROSS THE AREA. IF WE WERE TO
SEE LOWER TD VALUES ADVECT INTO THE CWA...THEN WE COULD BREAK A FEW
LOW TEMPERATURE RECORDS TONIGHT...WITH VALUES IN THE UPPER 30S.
PREVIOUS GUIDANCE WAS BRINGING MUCH LOWER TD VALUES INTO THE AREA
TONIGHT. HOWEVER...BASED ON UPSTREAM TRENDS AND CURRENT GUIDANCE TD
VALUES SHOULD REMAIN 40F OR HIGHER...WHICH WILL LIMIT COOLING
POTENTIAL.
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 226 PM MDT FRI SEP 7 2012
SATURDAY THROUGH SUNDAY NIGHT WILL REMAIN DRY AS THE UPPER LEVEL
RIDGE CURRENTLY OVER THE SOUTHERN CONUS BUILDS NORTHWARD OVER THE
GREAT BASIN AND EXPANDS EAST INTO THE PLAINS. SUNDAY AFTERNOON AND
SUNDAY NIGHT THE RIDGE WILL FLATTEN OUT AS A SHORT WAVE TROUGH MOVES
ACROSS IT. THE SHORT WAVE TROUGH WILL MOVE INTO THE AREA SUNDAY
NIGHT. HOWEVER AM ONLY EXPECTING SOME CLOUDS TO DEVELOP WITH THE
TROUGH DUE TO THE SHALLOW MOIST LAYER TO WORK WITH BETWEEN 500-600MB.
TUESDAY THROUGH FRIDAY WILL HAVE CHANCES FOR PRECIPITATION ALMOST
EVERY DAY. TUESDAY AN UPPER LEVEL SHORT WAVE TROUGH AND ASSOCIATED
SURFACE TROUGH MOVE ACROSS THE AREA PROVIDING AN OPPORTUNITY FOR
SOME LOCATIONS TO RECEIVE RAINFALL. TUESDAY NIGHT INTO WEDNESDAY
ANOTHER UPPER LEVEL SHORT WAVE TROUGH FOLLOWS A COLD FRONT THROUGH
THE AREA...OFFERING A SHOT FOR MORE WIDE SPREAD RAINFALL. THE NEXT
BEST CHANCE FOR WIDE SPREAD RAINFALL COMES WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT AS AN UPPER LEVEL LONG WAVE TROUGH MOVES ACROSS THE PLAINS. THERE
MAY BE SOME LINGERING STORM ACTIVITY ON FRIDAY AS THE TROUGH DEPARTS
THE AREA. HIGH TEMPERATURES WILL BE WARMEST ON MONDAY AND TUESDAY AHEAD OF THE
COLD FRONT...ROUGHLY 10 DEGREES ABOVE NORMAL. FROM WEDNESDAY
THROUGH FRIDAY HIGH TEMPERATURES WILL BE ALMOST 10 DEGREES BELOW
NORMAL. LOW TEMPERATURES FOR THE PERIOD WILL BE NEAR NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 500 PM MDT FRI SEP 7 2012
VFR THROUGH THE PERIOD AT KGLD AND KMCK. SFC HIGH TO MOVE OVER THE
TERMINALS THROUGH THE PERIOD. SHOULD SEE A RAPID DECREASE IN
CLOUDINESS SHORTLY AFTER 00Z WITH THE LOSS OF DAYTIME HEATING AND
AXIS OF 850-500 MOISTURE PUSHES OFF TO THE SOUTHWEST. MAY SEE SOME
FAIR WX CU AT KGLD AROUND 18Z WITH NORTHWEST WINDS NEAR 10 KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
303 PM MDT THU SEP 6 2012
.UPDATE...
ISSUED AT 259 PM MDT THU SEP 6 2012
UPDATED FORECAST TO INCLUDE THE SEVERE THUNDERSTORM WATCH THIS
AFTERNOON AND EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 149 PM MDT THU SEP 6 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS CONTINUE TO INDICATE WESTERLY
FLOW ACROSS THE INTER-MOUNTAIN WEST AND HIGH PLAINS JUST NORTH OF
SOUTHWESTERN CONUS RIDGE. AT THE SURFACE A TROUGH/DRY LINE HAS
SHIFTED EAST TO LIE FROM JUST WEST OF MCCOOK NEBRASKA...BETWEEN
GOODLAND AND COLBY KANSAS...AND THEN WEST OF TRIBUNE KANSAS. TD
VALUES IN THE UPPER 50S/LOW 60S AND MIXED LAYER CAPES IN EXCESS OF
1000 J/KG ARE CURRENTLY EAST OF THIS DRY LINE...WITH MUCH MORE
STABLE AIR MASS TO THE WEST OF THIS FEATURE.
SURFACE CONVERGENCE AHEAD OF THIS DRY LINE SHOULD HELP OVERCOME
WEAKENING CAP LATER THIS AFTERNOON AND EARLY THIS EVENING...WITH
THUNDERSTORM COVERAGE INCREASING FURTHER EAST WHERE BETTER LARGE
SCALE FORCING IS EXPECTED. BASED ON MODEL SOUNDINGS LCL VALUES
REMAIN HIGH...WITH DEEP MIXED LAYER TO ABOUT 650 MB INDICATIVE OF
MICROBURST POTENTIAL WITH THUNDERSTORMS. IN ADDITION...SUPERCELL
THUNDERSTORMS WILL BE A POSSIBILITY....WITH 0-6KM BULK SHEAR VALUES
PROGGED TO BE AROUND 40KT OR HIGHER...AND WITH MIXED LAYER CAPE IN
EXCESS OF 1500 J/KG. LCL VALUES WILL BE FAIRLY HIGH IN THE 8-10KFT
RANGE...SO IM NOT AS CONCERNED ABOUT A TORNADO THREAT WITH THIS
ACTIVITY.
A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CWA FROM THE NW AFTER
MIDNIGHT...WITH LARGE PRESSURE RISES AND INCREASING H85 WINDS BEHIND
THE FRONT POSSIBLY RESULTING IN ADVISORY CRITERIA WINDS. OTHER THAN
THE 12Z NAM...MOST GUIDANCE IS VERY MARGINAL ON THIS...SO I DECIDED
AGAINST ISSUING AN ADVISORY THIS FORECAST CYCLE. AHEAD OF THIS FRONT
ELEVATED INSTABILITY AND MOISTURE WILL BEGIN TO BUILD BACK TO THE
WEST...WITH ISOLATED THREAT FOR CONVECTION RETURNING AFTER MIDNIGHT
THROUGH FRIDAY MORNING AS THE FRONT MOVES ACROSS THE REGION.
CONFIDENCE IS LOW AT THIS TIME...AND MOST GUIDANCE IS NOT CURRENTLY
INITIATING ANYTHING WITH THIS FROPA...SO I LIMITED POPS TO SLIGHT
CHANCE CATEGORY. LARGE SCALE SUBSIDENCE SHOULD BRING DRY CONDITIONS
BACK TO THE CWA FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 215 PM MDT THU SEP 6 2012
DRY AND MILD CONDITIONS ON FRIDAY NIGHT AND SATURDAY WILL
TRANSITION TO DRY AND WARM CONDITIONS DURING THE FIRST PART OF
NEXT WEEK AS THE UPPER RIDGE MOVES FROM THE ROCKIES TO THE HIGH
PLAINS AND THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE SLIDES
INTO THE SOUTHERN PLAINS. SOUTHERLY SURFACE RETURN FLOW
ESTABLISHES OVER THE CENTRAL HIGH PLAINS ON SUNDAY AND CONTINUES
THROUGH MONDAY AS THE SURFACE LEE TROUGH DEEPENS AND THE UPPER
RIDGE TRANSITIONS OVER THE PLAINS STATES. TEMPERATURES ARE
EXPECTED TO WARM BACK UP INTO THE 90S BY MONDAY AS A RESULT AHEAD
OF THE NEXT FRONT DUE THROUGH THE REGION DURING THE DAY ON TUESDAY.
ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ON
TUESDAY IN THE VICINITY OF THE FRONT. STORMS WILL BECOME MORE
WIDESPREAD AND CONTINUE THROUGH TUESDAY NIGHT AND INTO WEDNESDAY
AS THE FLOW OVER THE CENTRAL HIGH PLAINS BECOMES MORE ZONAL AND A
SERIES OF SHORT WAVE TROUGHS MOVES THROUGH THE FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1130 AM MDT THU SEP 6 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. THUNDERSTORM ACTIVITY SHOULD REMAIN SOUTHEAST
OF BOTH TERMINALS...WITH LOW PROBABILITY OF A THUNDERSTORM AT
KGLD. DO NOT PLAN ON INCLUDING IN TAFS AT THIS TIME DUE TO
LIMITED COVERAGE. WINDS AT KMCK WILL REMAIN GUSTY THIS AFTERNOON
AHEAD OF SURFACE TROUGH...WITH WINDS DECREASING AND BECOMING
VARIABLE AT BOTH TERMINALS AS THIS SHIFTS EAST. COLD FRONT WILL
BRING GUSTY NORTH WINDS LATE TONIGHT THROUGH FRIDAY MORNING. A FEW
GUSTS IN EXCESS OF 40KT CANT BE RULED OUT...HOWEVER PREVAILING
GUSTS SHOULD BE IN THE 30-40KT RANGE AT BOTH TERMINALS. MAY NEED
TO INCREASE BASED ON TRENDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
236 PM MDT THU SEP 6 2012
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 149 PM MDT THU SEP 6 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS CONTINUE TO INDICATE WESTERLY
FLOW ACROSS THE INTER-MOUNTAIN WEST AND HIGH PLAINS JUST NORTH OF
SOUTHWESTERN CONUS RIDGE. AT THE SURFACE A TROUGH/DRY LINE HAS
SHIFTED EAST TO LIE FROM JUST WEST OF MCCOOK NEBRASKA...BETWEEN
GOODLAND AND COLBY KANSAS...AND THEN WEST OF TRIBUNE KANSAS. TD
VALUES IN THE UPPER 50S/LOW 60S AND MIXED LAYER CAPES IN EXCESS OF
1000 J/KG ARE CURRENTLY EAST OF THIS DRY LINE...WITH MUCH MORE
STABLE AIR MASS TO THE WEST OF THIS FEATURE.
SURFACE CONVERGENCE AHEAD OF THIS DRY LINE SHOULD HELP OVERCOME
WEAKENING CAP LATER THIS AFTERNOON AND EARLY THIS EVENING...WITH
THUNDERSTORM COVERAGE INCREASING FURTHER EAST WHERE BETTER LARGE
SCALE FORCING IS EXPECTED. BASED ON MODEL SOUNDINGS LCL VALUES
REMAIN HIGH...WITH DEEP MIXED LAYER TO ABOUT 650 MB INDICATIVE OF
MICROBURST POTENTIAL WITH THUNDERSTORMS. IN ADDITION...SUPERCELL
THUNDERSTORMS WILL BE A POSSIBILITY....WITH 0-6KM BULK SHEAR VALUES
PROGGED TO BE AROUND 40KT OR HIGHER...AND WITH MIXED LAYER CAPE IN
EXCESS OF 1500 J/KG. LCL VALUES WILL BE FAIRLY HIGH IN THE 8-10KFT
RANGE...SO IM NOT AS CONCERNED ABOUT A TORNADO THREAT WITH THIS
ACTIVITY.
A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CWA FROM THE NW AFTER
MIDNIGHT...WITH LARGE PRESSURE RISES AND INCREASING H85 WINDS BEHIND
THE FRONT POSSIBLY RESULTING IN ADVISORY CRITERIA WINDS. OTHER THAN
THE 12Z NAM...MOST GUIDANCE IS VERY MARGINAL ON THIS...SO I DECIDED
AGAINST ISSUING AN ADVISORY THIS FORECAST CYCLE. AHEAD OF THIS FRONT
ELEVATED INSTABILITY AND MOISTURE WILL BEGIN TO BUILD BACK TO THE
WEST...WITH ISOLATED THREAT FOR CONVECTION RETURNING AFTER MIDNIGHT
THROUGH FRIDAY MORNING AS THE FRONT MOVES ACROSS THE REGION.
CONFIDENCE IS LOW AT THIS TIME...AND MOST GUIDANCE IS NOT CURRENTLY
INITIATING ANYTHING WITH THIS FROPA...SO I LIMITED POPS TO SLIGHT
CHANCE CATEGORY. LARGE SCALE SUBSIDENCE SHOULD BRING DRY CONDITIONS
BACK TO THE CWA FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 215 PM MDT THU SEP 6 2012
DRY AND MILD CONDITIONS ON FRIDAY NIGHT AND SATURDAY WILL
TRANSITION TO DRY AND WARM CONDITIONS DURING THE FIRST PART OF
NEXT WEEK AS THE UPPER RIDGE MOVES FROM THE ROCKIES TO THE HIGH
PLAINS AND THE COOLER AREA OF HIGH PRESSURE AT THE SURFACE SLIDES
INTO THE SOUTHERN PLAINS. SOUTHERLY SURFACE RETURN FLOW
ESTABLISHES OVER THE CENTRAL HIGH PLAINS ON SUNDAY AND CONTINUES
THROUGH MONDAY AS THE SURFACE LEE TROUGH DEEPENS AND THE UPPER
RIDGE TRANSITIONS OVER THE PLAINS STATES. TEMPERATURES ARE
EXPECTED TO WARM BACK UP INTO THE 90S BY MONDAY AS A RESULT AHEAD
OF THE NEXT FRONT DUE THROUGH THE REGION DURING THE DAY ON TUESDAY.
ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ON
TUESDAY IN THE VICINITY OF THE FRONT. STORMS WILL BECOME MORE
WIDESPREAD AND CONTINUE THROUGH TUESDAY NIGHT AND INTO WEDNESDAY
AS THE FLOW OVER THE CENTRAL HIGH PLAINS BECOMES MORE ZONAL AND A
SERIES OF SHORT WAVE TROUGHS MOVES THROUGH THE FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1130 AM MDT THU SEP 6 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. THUNDERSTORM ACTIVITY SHOULD REMAIN SOUTHEAST
OF BOTH TERMINALS...WITH LOW PROBABILITY OF A THUNDERSTORM AT
KGLD. DO NOT PLAN ON INCLUDING IN TAFS AT THIS TIME DUE TO
LIMITED COVERAGE. WINDS AT KMCK WILL REMAIN GUSTY THIS AFTERNOON
AHEAD OF SURFACE TROUGH...WITH WINDS DECREASING AND BECOMING
VARIABLE AT BOTH TERMINALS AS THIS SHIFTS EAST. COLD FRONT WILL
BRING GUSTY NORTH WINDS LATE TONIGHT THROUGH FRIDAY MORNING. A FEW
GUSTS IN EXCESS OF 40KT CANT BE RULED OUT...HOWEVER PREVAILING
GUSTS SHOULD BE IN THE 30-40KT RANGE AT BOTH TERMINALS. MAY NEED
TO INCREASE BASED ON TRENDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
149 PM MDT THU SEP 6 2012
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 149 PM MDT THU SEP 6 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS CONTINUE TO INDICATE WESTERLY
FLOW ACROSS THE INTER-MOUNTAIN WEST AND HIGH PLAINS JUST NORTH OF
SOUTHWESTERN CONUS RIDGE. AT THE SURFACE A TROUGH/DRY LINE HAS
SHIFTED EAST TO LIE FROM JUST WEST OF MCCOOK NEBRASKA...BETWEEN
GOODLAND AND COLBY KANSAS...AND THEN WEST OF TRIBUNE KANSAS. TD
VALUES IN THE UPPER 50S/LOW 60S AND MIXED LAYER CAPES IN EXCESS OF
1000 J/KG ARE CURRENTLY EAST OF THIS DRY LINE...WITH MUCH MORE
STABLE AIR MASS TO THE WEST OF THIS FEATURE.
SURFACE CONVERGENCE AHEAD OF THIS DRY LINE SHOULD HELP OVERCOME
WEAKENING CAP LATER THIS AFTERNOON AND EARLY THIS EVENING...WITH
THUNDERSTORM COVERAGE INCREASING FURTHER EAST WHERE BETTER LARGE
SCALE FORCING IS EXPECTED. BASED ON MODEL SOUNDINGS LCL VALUES
REMAIN HIGH...WITH DEEP MIXED LAYER TO ABOUT 650 MB INDICATIVE OF
MICROBURST POTENTIAL WITH THUNDERSTORMS. IN ADDITION...SUPERCELL
THUNDERSTORMS WILL BE A POSSIBILITY....WITH 0-6KM BULK SHEAR VALUES
PROGGED TO BE AROUND 40KT OR HIGHER...AND WITH MIXED LAYER CAPE IN
EXCESS OF 1500 J/KG. LCL VALUES WILL BE FAIRLY HIGH IN THE 8-10KFT
RANGE...SO IM NOT AS CONCERNED ABOUT A TORNADO THREAT WITH THIS
ACTIVITY.
A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CWA FROM THE NW AFTER
MIDNIGHT...WITH LARGE PRESSURE RISES AND INCREASING H85 WINDS BEHIND
THE FRONT POSSIBLY RESULTING IN ADVISORY CRITERIA WINDS. OTHER THAN
THE 12Z NAM...MOST GUIDANCE IS VERY MARGINAL ON THIS...SO I DECIDED
AGAINST ISSUING AN ADVISORY THIS FORECAST CYCLE. AHEAD OF THIS FRONT
ELEVATED INSTABILITY AND MOISTURE WILL BEGIN TO BUILD BACK TO THE
WEST...WITH ISOLATED THREAT FOR CONVECTION RETURNING AFTER MIDNIGHT
THROUGH FRIDAY MORNING AS THE FRONT MOVES ACROSS THE REGION.
CONFIDENCE IS LOW AT THIS TIME...AND MOST GUIDANCE IS NOT CURRENTLY
INITIATING ANYTHING WITH THIS FROPA...SO I LIMITED POPS TO SLIGHT
CHANCE CATEGORY. LARGE SCALE SUBSIDENCE SHOULD BRING DRY CONDITIONS
BACK TO THE CWA FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 249 AM MDT THU SEP 6 2012
TOMORROW NIGHT-SATURDAY NIGHT...MUCH QUIETER WEATHER EXPECTED FOR
THE PERIOD AS COOL HIGH PRESSURE SETTLES OVER THE AREA. WITH LIGHT
WINDS...CLEAR SKIES AND MUCH DRIER AIR THINK TEMPERATURES HAVE THE
POTENTIAL TO BE THE COOLEST OF THE SEASON WITH TEMPERATURES DIPPING
INTO THE 40S BOTH EVENINGS AND COULD POSSIBLE SEE AN UPPER 30S IN
SOME OF THE LOW SPOTS. OTHERWISE EXPECT AFTERNOON HIGHS TO WARM BACK
INTO THE LOW 80S DESPITE THE COOLER MORNING STARTS.
A BROAD RIDGE WILL GRADUALLY BUILD INTO THE CENTRAL PLAINS AS
SURFACE HIGH PRESSURE MOVES INTO THE MISSOURI AND OHIO RIVER VALLEYS
BY EARLY NEXT WEEK...RESULTING IN QUIET WEATHER THROUGH THE EARLY
EXTENDED PERIOD. BY MONDAY AFTERNOON...STRONG LEE TROUGHING WILL
DEVELOP AHEAD OF AN UPPER LEVEL TROUGH THAT WILL SWING OUT OF
SOUTHWESTERN CANADA AND THROUGH THE NORTHERN ROCKIES. THE
ATTENDANT COLD FRONT WILL MOVE ACROSS THE REGION TUESDAY AFTERNOON
AND EVENING BRINGING ANOTHER CHANCE FOR THUNDERSTORMS THROUGH
EARLY WEDNESDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1130 AM MDT THU SEP 6 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. THUNDERSTORM ACTIVITY SHOULD REMAIN SOUTHEAST
OF BOTH TERMINALS...WITH LOW PROBABILITY OF A THUNDERSTORM AT
KGLD. DO NOT PLAN ON INCLUDING IN TAFS AT THIS TIME DUE TO
LIMITED COVERAGE. WINDS AT KMCK WILL REMAIN GUSTY THIS AFTERNOON
AHEAD OF SURFACE TROUGH...WITH WINDS DECREASING AND BECOMING
VARIABLE AT BOTH TERMINALS AS THIS SHIFTS EAST. COLD FRONT WILL
BRING GUSTY NORTH WINDS LATE TONIGHT THROUGH FRIDAY MORNING. A FEW
GUSTS IN EXCESS OF 40KT CANT BE RULED OUT...HOWEVER PREVAILING
GUSTS SHOULD BE IN THE 30-40KT RANGE AT BOTH TERMINALS. MAY NEED
TO INCREASE BASED ON TRENDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM/PMM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
201 PM CDT THU SEP 6 2012
.DISCUSSION...
CUMULUS FIELD IS FINALLY DEVELOPING...BUT WE MAY BE SEEING SOME
COMPRESSIONAL HEATING AHEAD OF THE APPROACHING CLOUDS EDGING
TOWARD THE NW CORNER OF THE CWA AT THIS TIME. UNDER THE CLOUDS LOW
90S RESIDE AND HAVE DEVELOPED A SUBSTANTIAL AREA OF DIFFERENTIAL
HEATING. WE HAVE RAISED TEMPS FOR THE NEXT COUPLE OF HOURS WHICH
ADMITTEDLY REALLY NEEDS THE CLOUDS TO HELP SOON. HEAT INDICES WILL
BE CLOSE...BUT MID 50S ARE A BIG HELP OVER NE TX...SE OK...AND
PERHAPS EVEN SW AR SOON. NEW ZONES ALREADY OUT. /24/
&&
.PREV DISCUSSION... /ISSUED 1129 AM CDT THU SEP 6 2012/
DISCUSSION...
SKIES BECOMING FAIR LATE THIS MORNING WITH A WEAK MID LEVEL
DISTURBACNE WHICH HAD SOME SHOWERS EARLIER ALONG AND SOUTH OF I-20
NOW MAY END UP YIELDING LITTLE IF ANY DURING THE AFTERNOON...BUT A
SLIGHT CHANCE WAS ADDED FOR THE SE ZONES. ALSO AND SLIGHTLY MORE
IMPRESSIVE QPF WISE THE SYSTEM RIDING ALONG THE RED RIVER OF
OK/TX. THIS IS LIKEWISE MORE OF A MID LEVEL SYSTEM...BUT THERE IS
SOME WEAK SFC CONVERGENCE IN PLAY AS WELL. NAM AND RAP MODELS
GENERATE SOME QPF FOR NE TX AND SE OK AS THIS SYSTEM WORKS EAST.
SHOULD ANYTHING BECOME SFC BASED THIS AFTERNOON...THEN CONVECTIVE
OUTFLOW WILL CONTINUE SHOWERS AND ISOLATED THUNDER TO JUST BEYOND
SUNSET IN THE I-30 CORRIDOR. FOR NOW HAVE ADDED NE TX/SE OK WITH A
SLIGHT CHANCE FOR THIS AFTERNOON.
OUR WARM SPOT IS IDABEL OK ALREADY AT 97...BUT THEIR DEW POINT IS
TOO LOW FOR THE HX TO BE ANY HIGHER THAN THE AIR TEMP AND WITH
INCREASING CLOUDS FOR THE LATE DAY...HAVE TOPPED SE OK EARLY THIS
AFTERNOON TEMP WISE AND REMOVED THE HEAT ADV FROM SE OK/ ADJACENT
NE TX. A FEW OTHER CHANGES TO HIGHS BASED ON TRENDS...BUT WILL
CONTINUE THE HEAT ADVISORY FROM NOON TO 7PM FOR AR/LA IN CWA. /24/
AVIATION...
MOSTLY VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
STILL SEEING LOW MVFR CIGS WHICH HAVE DEVELOPED OVER PORTIONS OF
DEEP E TX AFFECTING THE LFK TERMINAL...BUT THESE SHOULD SCATTER OUT
SHORTLY ONCE MIXING INCREASES. ALSO SEEING AN ACCAS FIELD ALONG THE
I-20 CORRIDOR OF EXTREME E TX/N LA...WHICH HAS GENERATED VERY
ISOLATED BUT ELEVATED -SHRA OVER THESE AREAS. HOWEVER...THIS CLOUD
FIELD SHOULD DISSIPATE BY MIDDAY/EARLY AFTERNOON...WITH A SCT CU
FIELD /AT BEST/ DEVELOPING AFTER 19Z ACROSS THE REGION...MORESO OVER
NCNTRL LA/SE AR. A WEAK SHORTWAVE OVER CNTRL OK WILL SHIFT E INTO SE
OK/WRN AR BY MID TO LATE AFTERNOON...WHICH MAY YIELD WIDELY SCT
ELEVATED CONVECTION OVER THESE AREAS...BUT SHOULD REMAIN N OF THE
TXK/ELD TERMINALS BEFORE DIMINISHING THIS EVENING WITH THE LOSS OF
HEATING. ASIDE FROM CIRRUS FROM THIS CONVECTION/DISTURBANCE
AFFECTING MAINLY THE AR TERMINALS OVERNIGHT...SKC WILL PREVAIL
ELSEWHERE THROUGH THE REMAINDER OF THE TAF PERIOD. SSW WINDS 4-7KTS
OVER E TX THIS AFTERNOON WILL BECOME LIGHT S AFTER 00Z. LIGHT S
WINDS ARE EXPECTED ELSEWHERE ACROSS SW AR/N LA DURING THE NEXT 24
HOURS. /15/
PREV DISCUSSION... /ISSUED 349 AM CDT THU SEP 6 2012/
DISCUSSION...
SAME OLD STORY AGAIN FOR TODAY...WITH THE UPPER RIDGE STILL
ANCHORED OVER W TX. A STALLED FRONTAL BOUNDARY PRESENT ACROSS SRN
OK/AR WILL AID ISOLD TO SCT CONVECTION ACROSS SE OK/SW AR. SOME
ADDITIONAL CLOUD COVER OVER THESE AREAS MAY KEEP TEMPS DOWN A
DEGREE OR TWO FROM WEDNESDAY`S HIGHS...BUT STILL WARM ENOUGH TO
PUSH HEAT INDICES TOWARD HEAT ADVISORY CRITERIA. FURTHER S INTO
LA...WARMER TEMPS AND LESS MIXING WILL ALSO PUSH HEAT INDICES
UPWARD. HAVE DECIDED TO GO WITH THE HEAT ADVISORY AGAIN FOR
TODAY ACROSS NE TX...SE OK...SW AR...NW AND N CENTRAL LA...THE
SAME AREA WE HAVE SEEN IN THE LAST FEW DAYS. AS IN PREVIOUS
DAYS...HEAT INDICES AT A FEW SPOTS MAY BRIEFLY REACH 105 DEGREES...
BUT THESE OCCURRENCES SHOULD BE ISOLD. FRIDAY IS SHAPING UP TO BE
QUITE WARM AS WELL...SO MAY SEE THE HEAT ADVISORY EXTENDED FOR ONE
MORE DAY IN LATER PACKAGES.
UPPER TROF OVER EXTREME SWRN CANADA WILL CONTINUE DIGGING SE
ACROSS THE PLAINS THROUGH FRIDAY...BRINGING A COLD FRONT AND RAIN
CHANCES BEGINNING LATE FRIDAY NIGHT AND CONTINUING THROUGH MOST OF
THE DAY SATURDAY. SOME POTENTIAL FOR A FEW SEVERE STORMS DOES
EXIST...BUT APPEARS THAT THIS THREAT WILL MAINLY BE CONFINED TO
PARTS OF SW AR/N CENTRAL LA. AS HAS BEEN DISCUSSED OVER THE LAST
FEW MORNINGS...SIGNIFICANTLY COOLER TEMPS AND DRIER AIR ARE
EXPECTED BEHIND THE FRONT AS HIGH PRESSURE BUILDS IN THE WAKE OF
THE TROF BY SATURDAY EVENING.
THE UPPER RIDGE IS FCST TO BEGIN REINFORCING ITSELF BACK OVER THE
SRN PLAINS BY EARLY IN THE WORK WEEK...WHICH WILL HELP TEMPS WARM
BACK TO NEAR NORMAL FOR THE REMAINDER OF THE PD. MODELS HINTING AT
A DISTURBANCE IN THE NRN GULF BY MIDWEEK WHICH IS CURRENTLY FCST
TO TRAVERSE THE NRN GULF COAST THROUGH THE END OF THE PD. HOWEVER...
IT APPEARS ATTM THAT THIS FEATURE WILL HAVE VERY LITTLE IMPACT ON
OUR REGION...EXCEPT FOR BRINGING SOME PARTLY CLOUDY SKIES BACK. /12/
AVIATION...
MOSTLY VFR FLIGHT WEATHER TODAY AND TONIGHT. ONLY EXCEPTION MAY BE
PATCHY CIGS AROUND 15 HUNDRED FEET THIS MORNING ACROSS DEEP EAST
TEXAS BETWEEN 12Z AND 14Z. AFTER 18Z AND CONTINUING UNTIL AROUND
SUNSET...EXPECT ISOLATED TSTMS ALONG AND NORTH OF A IDABEL OK TO
MONROE LA LINE. SURFACE WIND SOUTH TO SOUTHWEST 5 TO 10 KTS EARLY
THIS MORNING BECOMING WEST TO SOUTHWEST AFTER 15Z. /14/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 102 76 101 75 86 / 10 10 10 30 40
MLU 100 75 99 74 88 / 10 10 10 30 40
DEQ 106 70 99 66 82 / 20 10 30 50 20
TXK 104 75 100 71 83 / 10 10 20 50 30
ELD 101 73 99 69 85 / 10 10 20 50 40
TYR 101 77 101 75 85 / 10 10 10 20 20
GGG 103 77 101 75 86 / 10 10 10 20 30
LFK 100 75 100 75 91 / 10 10 10 20 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: ARZ050-051-059>061-070>073.
LA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: LAZ001>006-010>014-017>022.
OK...NONE.
TX...NONE.
&&
$$
24
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1129 AM CDT THU SEP 6 2012
.DISCUSSION...
SKIES BECOMING FAIR LATE THIS MORNING WITH A WEAK MID LEVEL
DISTURBACNE WHICH HAD SOME SHOWERS EARLIER ALONG AND SOUTH OF I-20
NOW MAY END UP YIELDING LITTLE IF ANY DURING THE AFTERNOON...BUT A
SLIGHT CHANCE WAS ADDED FOR THE SE ZONES. ALSO AND SLIGHTLY MORE
IMPRESSIVE QPF WISE THE SYSTEM RIDING ALONG THE RED RIVER OF
OK/TX. THIS IS LIKEWISE MORE OF A MID LEVEL SYSTEM...BUT THERE IS
SOME WEAK SFC CONVERGENCE IN PLAY AS WELL. NAM AND RAP MODELS
GENERATE SOME QPF FOR NE TX AND SE OK AS THIS SYSTEM WORKS EAST.
SHOULD ANYTHING BECOME SFC BASED THIS AFTERNOON...THEN CONVECTIVE
OUTFLOW WILL CONTINUE SHOWERS AND ISOLATED THUNDER TO JUST BEYOND
SUNSET IN THE I-30 CORRIDOR. FOR NOW HAVE ADDED NE TX/SE OK WITH A
SLIGHT CHANCE FOR THIS AFTERNOON.
OUR WARM SPOT IS IDABEL OK ALREADY AT 97...BUT THEIR DEW POINT IS
TOO LOW FOR THE HX TO BE ANY HIGHER THAN THE AIR TEMP AND WITH
INCREASING CLOUDS FOR THE LATE DAY...HAVE TOPPED SE OK EARLY THIS
AFTERNOON TEMP WISE AND REMOVED THE HEAT ADV FROM SE OK/ ADJACENT
NE TX. A FEW OTHER CHANGES TO HIGHS BASED ON TRENDS...BUT WILL
CONTINUE THE HEAT ADVISORY FROM NOON TO 7PM FOR AR/LA IN CWA. /24/
&&
.AVIATION...
MOSTLY VFR FLIGHT CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
STILL SEEING LOW MVFR CIGS WHICH HAVE DEVELOPED OVER PORTIONS OF
DEEP E TX AFFECTING THE LFK TERMINAL...BUT THESE SHOULD SCATTER OUT
SHORTLY ONCE MIXING INCREASES. ALSO SEEING AN ACCAS FIELD ALONG THE
I-20 CORRIDOR OF EXTREME E TX/N LA...WHICH HAS GENERATED VERY
ISOLATED BUT ELEVATED -SHRA OVER THESE AREAS. HOWEVER...THIS CLOUD
FIELD SHOULD DISSIPATE BY MIDDAY/EARLY AFTERNOON...WITH A SCT CU
FIELD /AT BEST/ DEVELOPING AFTER 19Z ACROSS THE REGION...MORESO OVER
NCNTRL LA/SE AR. A WEAK SHORTWAVE OVER CNTRL OK WILL SHIFT E INTO SE
OK/WRN AR BY MID TO LATE AFTERNOON...WHICH MAY YIELD WIDELY SCT
ELEVATED CONVECTION OVER THESE AREAS...BUT SHOULD REMAIN N OF THE
TXK/ELD TERMINALS BEFORE DIMINISHING THIS EVENING WITH THE LOSS OF
HEATING. ASIDE FROM CIRRUS FROM THIS CONVECTION/DISTURBANCE
AFFECTING MAINLY THE AR TERMINALS OVERNIGHT...SKC WILL PREVAIL
ELSEWHERE THROUGH THE REMAINDER OF THE TAF PERIOD. SSW WINDS 4-7KTS
OVER E TX THIS AFTERNOON WILL BECOME LIGHT S AFTER 00Z. LIGHT S
WINDS ARE EXPECTED ELSEWHERE ACROSS SW AR/N LA DURING THE NEXT 24
HOURS. /15/
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT THU SEP 6 2012/
DISCUSSION...
SAME OLD STORY AGAIN FOR TODAY...WITH THE UPPER RIDGE STILL
ANCHORED OVER W TX. A STALLED FRONTAL BOUNDARY PRESENT ACROSS SRN
OK/AR WILL AID ISOLD TO SCT CONVECTION ACROSS SE OK/SW AR. SOME
ADDITIONAL CLOUD COVER OVER THESE AREAS MAY KEEP TEMPS DOWN A
DEGREE OR TWO FROM WEDNESDAY`S HIGHS...BUT STILL WARM ENOUGH TO
PUSH HEAT INDICES TOWARD HEAT ADVISORY CRITERIA. FURTHER S INTO
LA...WARMER TEMPS AND LESS MIXING WILL ALSO PUSH HEAT INDICES
UPWARD. HAVE DECIDED TO GO WITH THE HEAT ADVISORY AGAIN FOR
TODAY ACROSS NE TX...SE OK...SW AR...NW AND N CENTRAL LA...THE
SAME AREA WE HAVE SEEN IN THE LAST FEW DAYS. AS IN PREVIOUS
DAYS...HEAT INDICES AT A FEW SPOTS MAY BRIEFLY REACH 105 DEGREES...
BUT THESE OCCURRENCES SHOULD BE ISOLD. FRIDAY IS SHAPING UP TO BE
QUITE WARM AS WELL...SO MAY SEE THE HEAT ADVISORY EXTENDED FOR ONE
MORE DAY IN LATER PACKAGES.
UPPER TROF OVER EXTREME SWRN CANADA WILL CONTINUE DIGGING SE
ACROSS THE PLAINS THROUGH FRIDAY...BRINGING A COLD FRONT AND RAIN
CHANCES BEGINNING LATE FRIDAY NIGHT AND CONTINUING THROUGH MOST OF
THE DAY SATURDAY. SOME POTENTIAL FOR A FEW SEVERE STORMS DOES
EXIST...BUT APPEARS THAT THIS THREAT WILL MAINLY BE CONFINED TO
PARTS OF SW AR/N CENTRAL LA. AS HAS BEEN DISCUSSED OVER THE LAST
FEW MORNINGS...SIGNIFICANTLY COOLER TEMPS AND DRIER AIR ARE
EXPECTED BEHIND THE FRONT AS HIGH PRESSURE BUILDS IN THE WAKE OF
THE TROF BY SATURDAY EVENING.
THE UPPER RIDGE IS FCST TO BEGIN REINFORCING ITSELF BACK OVER THE
SRN PLAINS BY EARLY IN THE WORK WEEK...WHICH WILL HELP TEMPS WARM
BACK TO NEAR NORMAL FOR THE REMAINDER OF THE PD. MODELS HINTING AT
A DISTURBANCE IN THE NRN GULF BY MIDWEEK WHICH IS CURRENTLY FCST
TO TRAVERSE THE NRN GULF COAST THROUGH THE END OF THE PD. HOWEVER...
IT APPEARS ATTM THAT THIS FEATURE WILL HAVE VERY LITTLE IMPACT ON
OUR REGION...EXCEPT FOR BRINGING SOME PARTLY CLOUDY SKIES BACK. /12/
AVIATION...
MOSTLY VFR FLIGHT WEATHER TODAY AND TONIGHT. ONLY EXCEPTION MAY BE
PATCHY CIGS AROUND 15 HUNDRED FEET THIS MORNING ACROSS DEEP EAST
TEXAS BETWEEN 12Z AND 14Z. AFTER 18Z AND CONTINUING UNTIL AROUND
SUNSET...EXPECT ISOLATED TSTMS ALONG AND NORTH OF A IDABEL OK TO
MONROE LA LINE. SURFACE WIND SOUTH TO SOUTHWEST 5 TO 10 KTS EARLY
THIS MORNING BECOMING WEST TO SOUTHWEST AFTER 15Z. /14/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 101 76 101 75 86 / 10 10 10 30 40
MLU 99 75 99 74 88 / 10 10 10 30 40
DEQ 100 70 99 66 82 / 20 10 30 50 20
TXK 101 75 100 71 83 / 10 10 20 50 30
ELD 99 73 99 69 85 / 10 10 20 50 40
TYR 98 77 101 75 85 / 10 10 10 20 20
GGG 100 77 101 75 86 / 10 10 10 20 30
LFK 100 75 100 75 91 / 10 10 10 20 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: ARZ050-051-059>061-070>073.
LA...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: LAZ001>006-010>014-017>022.
OK...NONE.
TX...NONE.
&&
$$
24/15
AREA FORECAST DISCUSSION
NWS GAYLORD MI
129 PM EDT THU SEP 6 2012
.SYNOPSIS...
ISSUED AT 327 AM EDT THU SEP 6 2012
A RELATIVELY ACTIVE PERIOD OF WEATHER IS EXPECTED THROUGH THE END OF
THE WEEK...AS ADDITIONAL DISTURBANCES ROTATE THROUGH THE REGION. A
BRIEF BREAK IN THE ACTIVE WEATHER IS EXPECTED INTO THIS EVENING...
WITH RAIN CHANCES INCREASING AGAIN LATER TONIGHT THROUGH FRIDAY. A
GENERALLY DRY AND MUCH COOLER WEEKEND IS EXPECTED...WITH JUST
PERHAPS A FEW LIGHT SHOWERS RETURNING FOR SATURDAY NIGHT. SLOWLY
MODERATING CONDITIONS ARE EXPECTED NEXT WORK WEEK.
&&
.UPDATE...
ISSUED AT 129 PM EDT THU SEP 6 2012
GOTTA LOVE PESKY FORECASTS LIKE THIS ONE! JUST LIKE THAT...A
COUPLE OF SHOWERS FIRED OFF NEAR GRAND TRAVERSE BAY...WITHIN THE
ENHANCED STRATOCU FIELD THAT HAS PLAGUED MUCH OF NORTHWEST LOWER
THROUGH THE MORNING. THESE WILL LIKELY CONTINUE TO WORK EAST THE
NEXT FEW HOURS...WITH POSSIBLY A FEW MORE DEVELOPING INTO
NORTHEAST LOWER AS WELL PER LATEST SHORT TERM GUIDANCE TRENDS.
ALSO LIKE THE EARLIER CALL FOR A FEW POSSIBLE SHOWERS OVER THE
EASTERN U.P. WHERE CU FIELD IS CURRENTLY DEVELOPING BENEATH MORE
PRONOUNCED UPPER COOL POOL. OUTSIDE OF THESE SHOWERS...GOING FCST
IS IN GOOD SHAPE AND HAVE MADE NO OTHER CHANGES.
UPDATE ISSUED AT 1016 AM EDT THU SEP 6 2012
FAIRLY QUIET WEATHER ACROSS THE REGION THROUGH THE DAY...BUT NOT
WITHOUT OUR FAIR SHARE OF "ISSUES" AS WE HEAD INTO THE AFTERNOON.
THE FIRST IS CLOUD COVER. HAVE SEEN QUITE THE PESKY PLUME OF BOTH
LOW AND MID CLOUDS ACROSS PARTS OF NORTHERN LOWER SINCE JUST
BEFORE SUNRISE...WITH THE MID CLOUDS BEING DRIVEN MAINLY BE
REMNANT WEAKISH INSTABILITY ABOVE A STEEPER 775-700MB LAPSE RATE
PLUME (SEE 12Z APX RAOB FOR HINTS OF THIS). EARLIER LAKE MICHIGAN
CONVECTION (AND SUBSEQUENT MID CLOUD FOR THAT MATTER) WAS LIKELY
DRIVEN BY LOW LEVEL PARCELS BEING LOFTED INTO THIS REMAINING
SKINNY INSTABILITY PLUME...WITH SOME HINTS THIS OCCURRED DUE TO A
NOTABLE MID LAKE (LAND BREEZE INDUCED?) CONVERGENCE AXIS. SUSPECT
THESE PESKY CLOUDS WILL HANG AROUND FOR A WHILE INTO
MIDDAY...WHILE LOWER STUFF GRADUALLY MIXES OUT. WILL PROBABLY SEE
AN OK AMOUNT OF DIURNAL CU DEVELOPMENT AS WELL...PARTICULARLY OVER
NORTHEAST LOWER AND INTERIOR EASTERN UPPER WHERE MEAN LOW LEVEL
WESTERLY FLOW WILL FAVOR BEST LAKE BREEZE CONVERGENCE.
WILL ALSO BE WATCHING WIND/DEW POINT TRENDS INTO THE AFTERNOON.
PER UPSTREAM POST-FRONTAL OBS IN MINNESOTA YESTERDAY...MIXING
ENDED UP DEEPER THAN PROGGED...AND SUSPECT THIS WILL BE THE CASE
HERE AS WELL (12Z APX RAOB LOOKS A LOT LIKE 12Z MPX ONE
YESTERDAY). AS SUCH...HAVE BOOSTED GUSTS THIS AFTN ALONG WITH
LOWERING DEW POINTS INTO THE 40S IN SPOTS. THIS STILL WON`T BE
ENOUGH TO GIVE US ANY BIG FIRE WX ISSUES...BUT MIN RH VALUES
SHOULD DIP WELL INTO THE 30S.
FINALLY...WILL HAVE TO WATCH THE POTENTIAL FOR SOME ISOLATED AFTN
SHOWERS OVER MAINLY EASTERN UPPER. THIS AREA WILL BE FAVORED BY
BEST LOW LEVEL CONVERGENCE BENEATH A SHARPER UPPER COOL POOL. PER
LATEST RUC FORECAST RAOBS...CAN ENVISION SQUEEZING OUT ENOUGH CAPE
(MAYBE 100-200J/KG) TO GIVE US A FEW SNEAKY SHOWERS. MEANWHILE...
DON`T FORESEE THIS HAPPENING ACROSS NORTHEAST LOWER WHERE RESIDUAL
CAP IN PLACE SHOULD KEEP THINGS IN CHECK. CERTAINLY WILL HAVE TO
KEEP AN EYE ON THIS THOUGH.
HAVE RAISED GOING HIGHS A COUPLE OF DEGREES PER LATEST TRENDS AND
LACK OF ANY REAL ONGOING ADVECTION TODAY. WILL SEE READINGS RANGE
FROM THE MID 70S FAR NORTH TO AROUND 80 ACROSS MANY SPOTS FOR
NORTHERN LOWER.
UPDATE ISSUED AT 621 AM EDT THU SEP 6 2012
FAIRLY QUIET CONDITIONS THIS MORNING WITH CLEAR TO PARTLY CLOUDY
SKIES AND PATCHY DENSE FOG OUT THERE. HOT SPOT OF CONVECTION OVER
CENTRAL LAKE MICHIGAN...JUST WEST OF MANISTEE OVER THE LAST FEW
HOURS...WITH A NUMBER OF SMALL SHOWERS (EVEN SOME THUNDER) COMING
ONSHORE IN THAT AREA BUT DYING SOON AFTER. IN ANY EVENT...HAVE
ISOLATED SHOWERS/THUNDER IN THAT AREA THROUGH 12Z...HOPEFULLY THAT
WILL BE LONG ENOUGH.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 327 AM EDT THU SEP 6 2012
MID-UPPER LOW LOCATED OVER NRN MANITOBA/NW ONTARIO WITH BROAD
TROUGHING SPANNING MUCH OF THE NRN CONUS. SHORT WAVE IMPULSE
DROPPING DOWN INTO THE NRN ROCKIES ACCOMPANIED BU A DEVELOPING
WEST-EAST UPPER JET CORE ACROSS THE NRN PLAINS. SHORT WAVE IMPULSE
AND UPPER JET FEATURE WILL BE THE NEXT WEATHER MAKER FOR THE WESTERN
GREAT LAKES...AS IT PUNCHES INTO THE REGION AND ULTIMATELY CARVES
OUT A FAIRLY SUBSTANTIAL TROUGH THROUGH THE WEEKEND. IN THE
MEANTIME...IN THE WAKE OF YESTERDAYS COLD FRONT...ILL DEFINED HIGH
PRESSURE AND A FAIRLY DRY AIRMASS IN THE PROCESS OF BUILDING INTO
THE REGION.
TODAY...OVERALL QUIET AS ILL-DEFINED HIGH PRESSURE SLIDES THROUGH
THE REGION. THAT SAID...THERE IS A LITTLE BIT OF ELEVATED
INSTABILITY WORKING INTO THE REGION FROM THE WEST...EVIDENCED BY THE
POCKETS OF MID CLOUD (ACCAS). WEAK SYNOPTIC FORCING ACROSS LOWER
MICHIGAN AND STRONGER MID LEVEL FLOW HAS SPARKED A LONE ELEVATED
SHOWER OVER CENTRAL LAKE MICHIGAN. WILL KEEP AN EYE ON THAT TO SEE
IF WE HAVE TO ADD ISOLATED POPS TO THE FORECAST ALONG THE M-55
CORRIDOR THIS MORNING. OTHERWISE...COOLER AIR ALOFT/DEEPER MIXED
LAYER AND DAYTIME HEATING WILL LEAD TO SCT-BKN CU DEVELOPMENT TODAY.
FORECAST SOUNDINGS DONT SHOW ENOUGH INSTABILITY TO WARRANT
POPS...BUT DAY CREW WILL NEED TO WATCH FOR ANY HEATING OF THE DAY
INDUCED SHOWERS POPPING UP.
TONIGHT...QUIET EVENING. THEN...AFOREMENTIONED UPSTREAM SHORT WAVE
IMPULSE AND DEVELOPING UPPER JET STREAK WILL ADVANCE ACROSS THE
UPPER MIDWEST AND BEGIN TO PUNCH ACROSS NRN MICHIGAN BY FRIDAY
MORNING. THIS LEADS TO A STRENGTHENING BAND OF MID LEVEL
F-GEN/RESULTING QG-UPWARD ASCENT PUNCHING ACROSS NRN MICHIGAN BY
MORNING (AND EVENTUALLY THROUGH LOWER MICHIGAN ON FRIDAY). CURRENT
TIMING SUGGESTS MOST OF TONIGHT WILL BE DRY...WITH RAINFALL
SPREADING THROUGH EASTERN UPPER MICHIGAN/TIP OF THE MITT TOWARD
MORNING. HAVE TWEAKED FORECAST POPS/WEATHER ACCORDINGLY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM EDT THU SEP 6 2012
RATHER BUSY EXTENDED FORECAST...ESPECIALLY DURING THE EARLY
PERIODS...AS ELONGATED CENTRAL CANADA CENTERED TROUGHING MOVES
EAST...PARTIALLY A BY-PRODUCT OF STRONG SHORTWAVE TROUGH ROUNDING
ITS BASE INTO THE LAKES REGION FRIDAY INTO THE WEEKEND. LACK OF
DOWNSTREAM BLOCKING AND MAINTENANCE OF UPSTREAM KICKER SYSTEMS
EXPECTED TO KEEP THIS TROUGH AXIS FAIRLY TRANSIENT...A SOLUTION
GENERALLY NOW WELL GREED UPON BY NEARLY ALL AVAILABLE GUIDANCE.
PATTERN LOOKS TO BECOME A TOUCH MORE ZONAL DURING THE COURSE OF NEXT
WORK WEEK...ONCE AGAIN PROPELLING THE MOST "ACTIVE" WEATHER TO
REGIONS NORTH OF THE BORDER. FORECAST CONCERNS CENTER ON IMPACTS OF
LATE WEEK SYSTEM (BOTH SYNOPTIC AND LAKE ENHANCED/EFFECT RAIN
CHANCES)...AS WELL AS TEMPERATURE AND CLOUD TRENDS THROUGHOUT THE
PERIOD.
STILL APPEARS A DECENT BAND OF MUCH NEEDED RAINFALL WILL DRIFT
SOUTHEAST ACROSS THE NORTH WOODS FRIDAY...COURTESY OF AFOREMENTIONED
APPROACHING STRONG WAVE ENTICING LOW/MID LEVEL FGEN RESPONSE...ALL
OVER-TOPPED BY DECENT EXIT REGION UPPER JET DYNAMICS. DESPITE DECENT
AGREEMENT AMONGST GUIDANCE ON THE ABOVE...RECENT DRY STRETCH OF
WEATHER AND OVERALL THEME OF UNDER-PERFORMING RAIN SYSTEMS LATELY
PREVENTS A CATEGORICAL MENTION (INHERITED LIKELY WILL SUFFICE...WITH
JUST SOME COSMETIC CHANGES ON TIMING). POTENTIAL DOES EXIST FOR AT
LEAST SOME DECENT RAINFALL AS ABOVE DYNAMICS INTERACT WITH AN
APPRECIABLY MOIST AIRMASS (PWAT VALUES AOA 1 INCH). SIGNIFICANT
QUESTIONS START TO ARISE FRIDAY NIGHT INTO SATURDAY AS INITIAL
POSITIVELY TILTED TROUGH CONTINUES TO DIG AND TAKE ON A MORE NEUTRAL
APPEARANCE BY SATURDAY. MODELS CONTINUE TO STRUGGLE WITH JUST HOW
PROGRESSIVE THE ABOVE UNFOLDS...WITH NOW THE NEW 00Z UKMET AND ECMWF
THE MOST AGGRESSIVE IN DRIVING SIGNIFICANT EASTERN LAKES SURFACE LOW
DEVELOPMENT (AND HENCE A SLOWER SOLUTION)...RESULTING IN WIDESPREAD
RAINS HOLDING ON FRIDAY NIGHT INTO SATURDAY FOR NORTHEAST LOWER.
VAST MAJORITY OF OTHER PROGS...INCLUDING THE PREVIOUS MUCH SLOWER
AND WRAPPED-UP NAM-WRF...MORE PROGRESSIVE...DRIVING THE RAIN THREAT
EAST OF THE REGION BY LATER FRIDAY NIGHT. INHERITED FORECAST KINDA
LEFT OPEN THE POSSIBILITY OF THIS SLOWER SCENARIO...AT LEAST KEEPING
SOME RAIN MENTION ACROSS THE SOUTHEAST. GIVEN UNCERTAINTY...CAN
SIMPLY FIND ON COMPELLING ARGUMENT TO DEVIATE FROM THIS PHILOSOPHY.
WILL ALSO NEED TO WATCH FOR SOME LIGHT NORTHERN LAKE MICHIGAN
ENHANCED SHOWERS FRIDAY NIGHT AS NNW FLOW CAA DROPS H85 TEMPERATURES
INTO THE LOWER AND MIDDLE SINGLE DIGITS. ASSUMING THE FASTER IDEA
WORKS OUT...EXPECTING TO SEE A DRY SATURDAY WITH INITIAL LAKE DRIVEN
MORNING CLOUDS GIVING WAY TO WIDESPREAD INTERIOR SC FIELD AS THERMAL
TROUGH LINGERS OVERHEAD. COMBINATION OF CLOUDS/RAIN AND FLOW
BECOMING INCREASINGLY DIRECTED OUT OF CANADA WILL KEEP READINGS BOTH
FRIDAY AND SATURDAY SIGNIFICANTLY COOLER THAT WHAT HAS BEEN OBSERVED
LATELY...WITH HIGHS FRIDAY IN THE 60S AND LOWER 70S...COOLING
FURTHER INTO THE 60S AREA-WIDE SATURDAY.
EVIDENCE CONTINUES TO SUPPORT ADDITIONAL ENERGY DIVING SOUTH ON
BACKSIDE OF HOPEFULLY THEN DEPARTING TROUGH SATURDAY NIGHT...PERHAPS
KICKING OFF A FEW ADDITIONAL LIGHT SHOWERS (LAKE ENHANCED?). BARRING
ANY SIGNIFICANT SURPRISES TO DEPARTURE OF EASTERN LAKES
TROUGHING...REST OF THE FORECAST SHAPING UP TO BE A QUIET ONE AS
FLOW BECOMES MORE ZONAL AND ACTIVE WEATHER SHIFTS NORTH INTO CANADA.
TRENDS STILL SUPPORTING A MOISTURE STARVED COLD FRONTAL PASSAGE
WEDNESDAY...WITH A LOW END SHOWER THREAT ACCOMPANYING IT.
OTHERWISE...MULTI-PERIODS OF DRY WEATHER IS EXPECTED ALONG WITH A
SLOW MODERATING TREND. HIGHS STILL STUCK IN THE 60S ON SUNDAY WILL
GRADUALLY WARM WELL INTO THE 70S BY TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 129 PM EDT THU SEP 6 2012
PESKY CUMULUS AND STRATOCUMULUS WILL CONTINUE TO GRADUALLY WORK
EAST THROUGH THE AFTERNOON...WITH A COUPLE OF SHOWERS ALSO
LIKELY...THOUGH MAINLY IN BETWEEN TERMINAL SITES. SKIES ARE
EXPECTED TO CLEAR FOR A TIME INTO THE EVENING AND FIRST HALF OF
THE OVERNIGHT HOURS...BEFORE MID AND HIGH CLOUDS THICKEN AHEAD OF
OUR NEXT APPROACHING UPPER TROUGH. TIMING OF THESE CLOUDS SHOULD
PREVENT ANY SIGNIFICANT FOG DEVELOPMENT...BUT COULD PERHAPS SEE A
LITTLE SHALLOW GROUND FOG AROUND APN/PLN. APPROACHING UPPER WAVE
WILL BRING WITH IT INCREASING COVERAGE OF LIGHT RAIN THROUGH
FRIDAY MORNING...THOUGH WITH VFR CONDITIONS STILL EXPECTED.
&&
.MARINE...
ISSUED AT 327 AM EDT THU SEP 6 2012
NO MARINE HEADLINES NEEDED AT THIS POINT WITH LIGHTER NW-WESTERLY
WINDS THROUGH TODAY...AND MORE VARIABLE WINDS TONIGHT. SHARP
TROUGH AXIS WILL PASS THROUGH NRN MICHIGAN LATER IN THE DAY
FRIDAY. BEHIND THIS FEATURE...GUSTY NW WINDS WILL DEVELOP LATE
FRIDAY AND FRIDAY NIGHT...WITH SMALL CRAFT HEADLINES POSSIBLE
DURING THAT TIME.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MB
SHORT TERM...BA
LONG TERM...MB
AVIATION...LAWRENCE
MARINE...BA
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1016 AM EDT THU SEP 6 2012
.SYNOPSIS...
ISSUED AT 327 AM EDT THU SEP 6 2012
A RELATIVELY ACTIVE PERIOD OF WEATHER IS EXPECTED THROUGH THE END OF
THE WEEK...AS ADDITIONAL DISTURBANCES ROTATE THROUGH THE REGION. A
BRIEF BREAK IN THE ACTIVE WEATHER IS EXPECTED INTO THIS EVENING...
WITH RAIN CHANCES INCREASING AGAIN LATER TONIGHT THROUGH FRIDAY. A
GENERALLY DRY AND MUCH COOLER WEEKEND IS EXPECTED...WITH JUST
PERHAPS A FEW LIGHT SHOWERS RETURNING FOR SATURDAY NIGHT. SLOWLY
MODERATING CONDITIONS ARE EXPECTED NEXT WORK WEEK.
&&
.UPDATE...
ISSUED AT 1016 AM EDT THU SEP 6 2012
FAIRLY QUIET WEATHER ACROSS THE REGION THROUGH THE DAY...BUT NOT
WITHOUT OUR FAIR SHARE OF "ISSUES" AS WE HEAD INTO THE AFTERNOON.
THE FIRST IS CLOUD COVER. HAVE SEEN QUITE THE PESKY PLUME OF BOTH
LOW AND MID CLOUDS ACROSS PARTS OF NORTHERN LOWER SINCE JUST
BEFORE SUNRISE...WITH THE MID CLOUDS BEING DRIVEN MAINLY BE
REMNANT WEAKISH INSTABILITY ABOVE A STEEPER 775-700MB LAPSE RATE
PLUME (SEE 12Z APX RAOB FOR HINTS OF THIS). EARLIER LAKE MICHIGAN
CONVECTION (AND SUBSEQUENT MID CLOUD FOR THAT MATTER) WAS LIKELY
DRIVEN BY LOW LEVEL PARCELS BEING LOFTED INTO THIS REMAINING
SKINNY INSTABILITY PLUME...WITH SOME HINTS THIS OCCURRED DUE TO A
NOTABLE MID LAKE (LAND BREEZE INDUCED?) CONVERGENCE AXIS. SUSPECT
THESE PESKY CLOUDS WILL HANG AROUND FOR A WHILE INTO
MIDDAY...WHILE LOWER STUFF GRADUALLY MIXES OUT. WILL PROBABLY SEE
AN OK AMOUNT OF DIURNAL CU DEVELOPMENT AS WELL...PARTICULARLY OVER
NORTHEAST LOWER AND INTERIOR EASTERN UPPER WHERE MEAN LOW LEVEL
WESTERLY FLOW WILL FAVOR BEST LAKE BREEZE CONVERGENCE.
WILL ALSO BE WATCHING WIND/DEW POINT TRENDS INTO THE AFTERNOON.
PER UPSTREAM POST-FRONTAL OBS IN MINNESOTA YESTERDAY...MIXING
ENDED UP DEEPER THAN PROGGED...AND SUSPECT THIS WILL BE THE CASE
HERE AS WELL (12Z APX RAOB LOOKS A LOT LIKE 12Z MPX ONE
YESTERDAY). AS SUCH...HAVE BOOSTED GUSTS THIS AFTN ALONG WITH
LOWERING DEW POINTS INTO THE 40S IN SPOTS. THIS STILL WON`T BE
ENOUGH TO GIVE US ANY BIG FIRE WX ISSUES...BUT MIN RH VALUES
SHOULD DIP WELL INTO THE 30S.
FINALLY...WILL HAVE TO WATCH THE POTENTIAL FOR SOME ISOLATED AFTN
SHOWERS OVER MAINLY EASTERN UPPER. THIS AREA WILL BE FAVORED BY
BEST LOW LEVEL CONVERGENCE BENEATH A SHARPER UPPER COOL POOL. PER
LATEST RUC FORECAST RAOBS...CAN ENVISION SQUEEZING OUT ENOUGH CAPE
(MAYBE 100-200J/KG) TO GIVE US A FEW SNEAKY SHOWERS. MEANWHILE...
DON`T FORESEE THIS HAPPENING ACROSS NORTHEAST LOWER WHERE RESIDUAL
CAP IN PLACE SHOULD KEEP THINGS IN CHECK. CERTAINLY WILL HAVE TO
KEEP AN EYE ON THIS THOUGH.
HAVE RAISED GOING HIGHS A COUPLE OF DEGREES PER LATEST TRENDS AND
LACK OF ANY REAL ONGOING ADVECTION TODAY. WILL SEE READINGS RANGE
FROM THE MID 70S FAR NORTH TO AROUND 80 ACROSS MANY SPOTS FOR
NORTHERN LOWER.
UPDATE ISSUED AT 621 AM EDT THU SEP 6 2012
FAIRLY QUIET CONDITIONS THIS MORNING WITH CLEAR TO PARTLY CLOUDY
SKIES AND PATCHY DENSE FOG OUT THERE. HOT SPOT OF CONVECTION OVER
CENTRAL LAKE MICHIGAN...JUST WEST OF MANISTEE OVER THE LAST FEW
HOURS...WITH A NUMBER OF SMALL SHOWERS (EVEN SOME THUNDER) COMING
ONSHORE IN THAT AREA BUT DYING SOON AFTER. IN ANY EVENT...HAVE
ISOLATED SHOWERS/THUNDER IN THAT AREA THROUGH 12Z...HOPEFULLY THAT
WILL BE LONG ENOUGH.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 327 AM EDT THU SEP 6 2012
MID-UPPER LOW LOCATED OVER NRN MANITOBA/NW ONTARIO WITH BROAD
TROUGHING SPANNING MUCH OF THE NRN CONUS. SHORT WAVE IMPULSE
DROPPING DOWN INTO THE NRN ROCKIES ACCOMPANIED BU A DEVELOPING
WEST-EAST UPPER JET CORE ACROSS THE NRN PLAINS. SHORT WAVE IMPULSE
AND UPPER JET FEATURE WILL BE THE NEXT WEATHER MAKER FOR THE WESTERN
GREAT LAKES...AS IT PUNCHES INTO THE REGION AND ULTIMATELY CARVES
OUT A FAIRLY SUBSTANTIAL TROUGH THROUGH THE WEEKEND. IN THE
MEANTIME...IN THE WAKE OF YESTERDAYS COLD FRONT...ILL DEFINED HIGH
PRESSURE AND A FAIRLY DRY AIRMASS IN THE PROCESS OF BUILDING INTO
THE REGION.
TODAY...OVERALL QUIET AS ILL-DEFINED HIGH PRESSURE SLIDES THROUGH
THE REGION. THAT SAID...THERE IS A LITTLE BIT OF ELEVATED
INSTABILITY WORKING INTO THE REGION FROM THE WEST...EVIDENCED BY THE
POCKETS OF MID CLOUD (ACCAS). WEAK SYNOPTIC FORCING ACROSS LOWER
MICHIGAN AND STRONGER MID LEVEL FLOW HAS SPARKED A LONE ELEVATED
SHOWER OVER CENTRAL LAKE MICHIGAN. WILL KEEP AN EYE ON THAT TO SEE
IF WE HAVE TO ADD ISOLATED POPS TO THE FORECAST ALONG THE M-55
CORRIDOR THIS MORNING. OTHERWISE...COOLER AIR ALOFT/DEEPER MIXED
LAYER AND DAYTIME HEATING WILL LEAD TO SCT-BKN CU DEVELOPMENT TODAY.
FORECAST SOUNDINGS DONT SHOW ENOUGH INSTABILITY TO WARRANT
POPS...BUT DAY CREW WILL NEED TO WATCH FOR ANY HEATING OF THE DAY
INDUCED SHOWERS POPPING UP.
TONIGHT...QUIET EVENING. THEN...AFOREMENTIONED UPSTREAM SHORT WAVE
IMPULSE AND DEVELOPING UPPER JET STREAK WILL ADVANCE ACROSS THE
UPPER MIDWEST AND BEGIN TO PUNCH ACROSS NRN MICHIGAN BY FRIDAY
MORNING. THIS LEADS TO A STRENGTHENING BAND OF MID LEVEL
F-GEN/RESULTING QG-UPWARD ASCENT PUNCHING ACROSS NRN MICHIGAN BY
MORNING (AND EVENTUALLY THROUGH LOWER MICHIGAN ON FRIDAY). CURRENT
TIMING SUGGESTS MOST OF TONIGHT WILL BE DRY...WITH RAINFALL
SPREADING THROUGH EASTERN UPPER MICHIGAN/TIP OF THE MITT TOWARD
MORNING. HAVE TWEAKED FORECAST POPS/WEATHER ACCORDINGLY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM EDT THU SEP 6 2012
RATHER BUSY EXTENDED FORECAST...ESPECIALLY DURING THE EARLY
PERIODS...AS ELONGATED CENTRAL CANADA CENTERED TROUGHING MOVES
EAST...PARTIALLY A BY-PRODUCT OF STRONG SHORTWAVE TROUGH ROUNDING
ITS BASE INTO THE LAKES REGION FRIDAY INTO THE WEEKEND. LACK OF
DOWNSTREAM BLOCKING AND MAINTENANCE OF UPSTREAM KICKER SYSTEMS
EXPECTED TO KEEP THIS TROUGH AXIS FAIRLY TRANSIENT...A SOLUTION
GENERALLY NOW WELL GREED UPON BY NEARLY ALL AVAILABLE GUIDANCE.
PATTERN LOOKS TO BECOME A TOUCH MORE ZONAL DURING THE COURSE OF NEXT
WORK WEEK...ONCE AGAIN PROPELLING THE MOST "ACTIVE" WEATHER TO
REGIONS NORTH OF THE BORDER. FORECAST CONCERNS CENTER ON IMPACTS OF
LATE WEEK SYSTEM (BOTH SYNOPTIC AND LAKE ENHANCED/EFFECT RAIN
CHANCES)...AS WELL AS TEMPERATURE AND CLOUD TRENDS THROUGHOUT THE
PERIOD.
STILL APPEARS A DECENT BAND OF MUCH NEEDED RAINFALL WILL DRIFT
SOUTHEAST ACROSS THE NORTH WOODS FRIDAY...COURTESY OF AFOREMENTIONED
APPROACHING STRONG WAVE ENTICING LOW/MID LEVEL FGEN RESPONSE...ALL
OVER-TOPPED BY DECENT EXIT REGION UPPER JET DYNAMICS. DESPITE DECENT
AGREEMENT AMONGST GUIDANCE ON THE ABOVE...RECENT DRY STRETCH OF
WEATHER AND OVERALL THEME OF UNDER-PERFORMING RAIN SYSTEMS LATELY
PREVENTS A CATEGORICAL MENTION (INHERITED LIKELY WILL SUFFICE...WITH
JUST SOME COSMETIC CHANGES ON TIMING). POTENTIAL DOES EXIST FOR AT
LEAST SOME DECENT RAINFALL AS ABOVE DYNAMICS INTERACT WITH AN
APPRECIABLY MOIST AIRMASS (PWAT VALUES AOA 1 INCH). SIGNIFICANT
QUESTIONS START TO ARISE FRIDAY NIGHT INTO SATURDAY AS INITIAL
POSITIVELY TILTED TROUGH CONTINUES TO DIG AND TAKE ON A MORE NEUTRAL
APPEARANCE BY SATURDAY. MODELS CONTINUE TO STRUGGLE WITH JUST HOW
PROGRESSIVE THE ABOVE UNFOLDS...WITH NOW THE NEW 00Z UKMET AND ECMWF
THE MOST AGGRESSIVE IN DRIVING SIGNIFICANT EASTERN LAKES SURFACE LOW
DEVELOPMENT (AND HENCE A SLOWER SOLUTION)...RESULTING IN WIDESPREAD
RAINS HOLDING ON FRIDAY NIGHT INTO SATURDAY FOR NORTHEAST LOWER.
VAST MAJORITY OF OTHER PROGS...INCLUDING THE PREVIOUS MUCH SLOWER
AND WRAPPED-UP NAM-WRF...MORE PROGRESSIVE...DRIVING THE RAIN THREAT
EAST OF THE REGION BY LATER FRIDAY NIGHT. INHERITED FORECAST KINDA
LEFT OPEN THE POSSIBILITY OF THIS SLOWER SCENARIO...AT LEAST KEEPING
SOME RAIN MENTION ACROSS THE SOUTHEAST. GIVEN UNCERTAINTY...CAN
SIMPLY FIND ON COMPELLING ARGUMENT TO DEVIATE FROM THIS PHILOSOPHY.
WILL ALSO NEED TO WATCH FOR SOME LIGHT NORTHERN LAKE MICHIGAN
ENHANCED SHOWERS FRIDAY NIGHT AS NNW FLOW CAA DROPS H85 TEMPERATURES
INTO THE LOWER AND MIDDLE SINGLE DIGITS. ASSUMING THE FASTER IDEA
WORKS OUT...EXPECTING TO SEE A DRY SATURDAY WITH INITIAL LAKE DRIVEN
MORNING CLOUDS GIVING WAY TO WIDESPREAD INTERIOR SC FIELD AS THERMAL
TROUGH LINGERS OVERHEAD. COMBINATION OF CLOUDS/RAIN AND FLOW
BECOMING INCREASINGLY DIRECTED OUT OF CANADA WILL KEEP READINGS BOTH
FRIDAY AND SATURDAY SIGNIFICANTLY COOLER THAT WHAT HAS BEEN OBSERVED
LATELY...WITH HIGHS FRIDAY IN THE 60S AND LOWER 70S...COOLING
FURTHER INTO THE 60S AREA-WIDE SATURDAY.
EVIDENCE CONTINUES TO SUPPORT ADDITIONAL ENERGY DIVING SOUTH ON
BACKSIDE OF HOPEFULLY THEN DEPARTING TROUGH SATURDAY NIGHT...PERHAPS
KICKING OFF A FEW ADDITIONAL LIGHT SHOWERS (LAKE ENHANCED?). BARRING
ANY SIGNIFICANT SURPRISES TO DEPARTURE OF EASTERN LAKES
TROUGHING...REST OF THE FORECAST SHAPING UP TO BE A QUIET ONE AS
FLOW BECOMES MORE ZONAL AND ACTIVE WEATHER SHIFTS NORTH INTO CANADA.
TRENDS STILL SUPPORTING A MOISTURE STARVED COLD FRONTAL PASSAGE
WEDNESDAY...WITH A LOW END SHOWER THREAT ACCOMPANYING IT.
OTHERWISE...MULTI-PERIODS OF DRY WEATHER IS EXPECTED ALONG WITH A
SLOW MODERATING TREND. HIGHS STILL STUCK IN THE 60S ON SUNDAY WILL
GRADUALLY WARM WELL INTO THE 70S BY TUESDAY AND WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 621 AM EDT THU SEP 6 2012
BRIEF PERIOD OF MVFR OR IFR CONDITIONS POSSIBLE AT APN/PLN EARLY
THIS MORNING...DUE TO SHALLOW FOG. VFR CONDITIONS OVERALL TODAY
ALTHOUGH SCT-BKN CU DECK WILL DEVELOP MY MIDDAY. DONT THINK WE GET
ENOUGH VERTICAL DEVELOPMENT OF SHOWERS TO POP...BUT NE LOWER
MICHIGAN WOULD STAND THE BEST CHANCE FOR THAT TO OCCUR.
QUIET...CLEAR TO PARTLY CLOUDY SKIES THIS EVENING. THICKENING MID
CLOUD ARRIVES OVERNIGHT AS MID LEVEL IMPULSE AND UPPER JET STREAK
BEGINS TO NOSE INTO THE REGION. RAIN WITH THIS NEXT FEATURE...BUT
NOT REACHING THE TERMINAL SITES UNTIL AFTER 12Z FRIDAY.
&&
.MARINE...
ISSUED AT 327 AM EDT THU SEP 6 2012
NO MARINE HEADLINES NEEDED AT THIS POINT WITH LIGHTER NW-WESTERLY
WINDS THROUGH TODAY...AND MORE VARIABLE WINDS TONIGHT. SHARP
TROUGH AXIS WILL PASS THROUGH NRN MICHIGAN LATER IN THE DAY
FRIDAY. BEHIND THIS FEATURE...GUSTY NW WINDS WILL DEVELOP LATE
FRIDAY AND FRIDAY NIGHT...WITH SMALL CRAFT HEADLINES POSSIBLE
DURING THAT TIME.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...MB
SHORT TERM...BA
LONG TERM...MB
AVIATION...BA
MARINE...BA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
100 PM CDT THU SEP 6 2012
.SHORT TERM...
ISSUED AT 332 AM CDT THU SEP 6 2012
(TODAY THROUGH FRIDAY NIGHT)
STILL EATING CROW AFTER YESTERDAY`S BUSTED FORECAST...AND IT`S A
BITTER BIRD. THE COLD FRONT HAS MADE IT THROUGH KIRKSVILLE BUT IS
TAKING ITS TIME DRIFTING THROUGH THE NORTHWEST PORTION OF THE CWFA.
CURRENT THINKING IS THAT THE FRONT WILL CONTINUE DRIFTING SOUTHEAST
BUT WILL PROBABLY NOT CLEAR THE SOUTHERN PORTION OF THE CWFA BEFORE
AFTERNOON. RAP AND HRRR DEVELOP DECENT INSTABILITY IN EXCESS OF
2000 J/KG WITH LITTLE OR NO CAP. HAVE ADDED POPS SOUTH OF THE STL
METRO AREA ACROSS THE EASTERN OZARKS. ALSO...SINCE THE COLD AIR
ADVECTION IS SOMEWHAT LACKING FROM PREVIOUS FORECASTS...HAVE BUMPED
UP TEMPS A COUPLE OF DEGREES TODAY.
ATTENTION TURNS TO THE STRONG SHORTWAVE JUST NOW DROPPING INTO THE
CONUS FROM SOUTHEAST CANADA AND THE RESULTING STORM WHICH WILL MOVE
THROUGH FRIDAY AND FRIDAY NIGHT. THE WAVE`S PRESENTATION ON WATER
VAPOR IMAGERY IS PRETTY IMPRESSIVE FOR EARLY SEPTEMBER. THIS IS
ENCOURAGING FOR THE FORECAST. LATEST GUIDANCE KEEPS MUCH OF THE
AREA DRY TONIGHT...PRETTY MUCH ALL EXCEPT NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS. CAN`T QUITE BRING MYSELF TO PULL POPS OUT OF
THE REST OF THE AREA THO...SO HAVE LEFT THEM BE. ALL GUIDANCE HAS
THE SHORTWAVE DIVING INTO THE PLAINS FRIDAY MORNING AND THE
ASSOCIATED COLD FRONT MOVING THROUGH KIRKSVILLE BY AROUND 18Z. SPC
HAS US OUTLOOKED IN A SLIGHT RISK AND THIS LOOKS GOOD GIVEN THAT THE
NAM DEVELOPS INSTABILITY IN EXCESS OF 3000 J/KG AND PLENTY OF DEEP
LAYER SHEAR. HAVE BUMPED UP POPS TO OCCASIONAL DURING THE AFTERNOON
AND EARLY EVENING FOR PARTS OF THE AREA. LATEST GUIDANCE HAS THE
FRONT MOVING THOUGH FASTER THAN EARLIER FORECAST...SO HAVE CUT BACK
ON POPS AFTER MIDNIGHT.
CARNEY
&&
.LONG TERM...
ISSUED AT 358 AM CDT THU SEP 6 2012
(SATURDAY THROUGH WEDNESDAY)
PRIMARY CHANGE TO THE FORECAST FOR THE LONG TERM IS TO INCREASE HIGH
TEMPERATURES A BIT THIS WEEKEND AND EARLY NEXT WEEK. ALL OF THE
MODELS DROP A STRONG RIDGE INTO THE AREA THIS WEEKEND BEHIND THE
FRONT. WHEN WE INITIALLY BEGAN SEEING THIS STORM SYSTEM IN THE
MODELS SEVERAL DAYS AGO...THEY DEVELOPED A CLOSED LOW OVER THE GREAT
LAKES/OHIO VALLEY REGION. THE PAST FEW RUNS THE MODELS HAVE BECOME
PROGRESSIVE WITH THE WAVE. THIS SHOULD MEAN THAT INSTEAD OF
CONSIDERABLE CLOUDS AND WIDELY SCATTERED SHOWERS ON SATURDAY...IT
SHOULD BE MOSTLY SUNNY AND DRY. WITH THE MORE PROGRESSIVE
SOLUTION...THE WARM UP BACK TO NEAR NORMAL TEMPERATURES SHOULD OCCUR
MORE QUICKLY ON SUNDAY INTO EARLY NEXT WEEK. UPPER LEVEL RIDGE
BUILDS BACK INTO THE AREA BY TUESDAY. ANOTHER COLD FRONT LOOKS TO
BE APPROACHING THE AREA ON WEDNESDAY...BUT HAVE NOT PUT ANY POPS IN
THE FORECAST AT THIS TIME AS THE STRONG SURFACE RIDGE WHICH WILL
BRING US THIS WEEKEND`S COOL WEATHER LOOKS LIKE IT WILL LAY OUT DOWN
ACROSS THE SOUTHERN U.S. AND BLOCK ANY MOIST RETURN FLOW FROM THE
GULF.
CARNEY
&&
.AVIATION...
ISSUED AT 1250 PM CDT THU SEP 6 2012
CLUSTER OF SHOWERS AND THUNDERSTORMS OVER SOUTHWEST MISSOURI IS
TRACKING EASTWARD AND IS EXPECTED TO CONTINUE ON THAT COURSE
THROUGH THE AFTERNOON. THIS SHOULD KEEP IT SOUTH OF THE
TERMINALS...BUT WILL HAVE TO WATCH THE ST LOUIS AREA AS THE FRONT
HAS BECOME QUASI-STATIONARY THROUGH EAST CENTRAL MO AND SOUTHWEST
ILLINOIS. OTHERWISE VFR CONDITIONS EXPECTED THROUGH LATE TONIGHT.
A POTENT COLD FRONT WILL BEGIN TO MOVE INTO NORTHERN MISSOURI AND
WEST CENTRAL ILLINOIS ON FRIDAY MORNING. SHOWERS AND THUNDERSTORMS
SHOULD BE ONGOING ALONG/AHEAD OF THE FRONT LATE TONIGHT AND SHOULD
CONTINUE TO GROW THROUGH THE MORNING AND INTO THE AFTERNOON AS IT
MOVES INTO MO AND IL.
SPECIFICS FOR KSTL...
CLUSTER OF SHOWERS AND THUNDERSTORMS OVER SOUTHWEST MISSOURI IS
TRACKING EASTWARD AND IS EXPECTED TO STAY SOUTH OF THE
TERMINAL...BUT WILL HAVE TO WATCH CLOSELY AS THE FRONT HAS BECOME
QUASI-STATIONARY THROUGH THE ST LOUIS METRO. OTHERWISE VFR
CONDITIONS EXPECTED THROUGH AT LEAST MID MORNING ON FRIDAY.
SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF A POTENT
COLD FRONT ON FRIDAY...WITH THE BEST CHANCE IN THE 17-21Z TIME
FRAME.
GLASS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
628 AM CDT THU SEP 6 2012
.SHORT TERM...
ISSUED AT 332 AM CDT THU SEP 6 2012
(TODAY THROUGH FRIDAY NIGHT)
STILL EATING CROW AFTER YESTERDAY`S BUSTED FORECAST...AND IT`S A
BITTER BIRD. THE COLD FRONT HAS MADE IT THROUGH KIRKSVILLE BUT IS
TAKING ITS TIME DRIFTING THROUGH THE NORTHWEST PORTION OF THE CWFA.
CURRENT THINKING IS THAT THE FRONT WILL CONTINUE DRIFTING SOUTHEAST
BUT WILL PROBABLY NOT CLEAR THE SOUTHERN PORTION OF THE CWFA BEFORE
AFTERNOON. RAP AND HRRR DEVELOP DECENT INSTABILITY IN EXCESS OF
2000 J/KG WITH LITTLE OR NO CAP. HAVE ADDED POPS SOUTH OF THE STL
METRO AREA ACROSS THE EASTERN OZARKS. ALSO...SINCE THE COLD AIR
ADVECTION IS SOMEWHAT LACKING FROM PREVIOUS FORECASTS...HAVE BUMPED
UP TEMPS A COUPLE OF DEGREES TODAY.
ATTENTION TURNS TO THE STRONG SHORTWAVE JUST NOW DROPPING INTO THE
CONUS FROM SOUTHEAST CANADA AND THE RESULTING STORM WHICH WILL MOVE
THROUGH FRIDAY AND FRIDAY NIGHT. THE WAVE`S PRESENTATION ON WATER
VAPOR IMAGERY IS PRETTY IMPRESSIVE FOR EARLY SEPTEMBER. THIS IS
ENCOURAGING FOR THE FORECAST. LATEST GUIDANCE KEEPS MUCH OF THE
AREA DRY TONIGHT...PRETTY MUCH ALL EXCEPT NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS. CAN`T QUITE BRING MYSELF TO PULL POPS OUT OF
THE REST OF THE AREA THO...SO HAVE LEFT THEM BE. ALL GUIDANCE HAS
THE SHORTWAVE DIVING INTO THE PLAINS FRIDAY MORNING AND THE
ASSOCIATED COLD FRONT MOVING THROUGH KIRKSVILLE BY AROUND 18Z. SPC
HAS US OUTLOOKED IN A SLIGHT RISK AND THIS LOOKS GOOD GIVEN THAT THE
NAM DEVELOPS INSTABILITY IN EXCESS OF 3000 J/KG AND PLENTY OF DEEP
LAYER SHEAR. HAVE BUMPED UP POPS TO OCCASIONAL DURING THE AFTERNOON
AND EARLY EVENING FOR PARTS OF THE AREA. LATEST GUIDANCE HAS THE
FRONT MOVING THOUGH FASTER THAN EARLIER FORECAST...SO HAVE CUT BACK
ON POPS AFTER MIDNIGHT.
CARNEY
&&
.LONG TERM...
ISSUED AT 358 AM CDT THU SEP 6 2012
(SATURDAY THROUGH WEDNESDAY)
PRIMARY CHANGE TO THE FORECAST FOR THE LONG TERM IS TO INCREASE HIGH
TEMPERATURES A BIT THIS WEEKEND AND EARLY NEXT WEEK. ALL OF THE
MODELS DROP A STRONG RIDGE INTO THE AREA THIS WEEKEND BEHIND THE
FRONT. WHEN WE INITIALLY BEGAN SEEING THIS STORM SYSTEM IN THE
MODELS SEVERAL DAYS AGO...THEY DEVELOPED A CLOSED LOW OVER THE GREAT
LAKES/OHIO VALLEY REGION. THE PAST FEW RUNS THE MODELS HAVE BECOME
PROGRESSIVE WITH THE WAVE. THIS SHOULD MEAN THAT INSTEAD OF
CONSIDERABLE CLOUDS AND WIDELY SCATTERED SHOWERS ON SATURDAY...IT
SHOULD BE MOSTLY SUNNY AND DRY. WITH THE MORE PROGRESSIVE
SOLUTION...THE WARM UP BACK TO NEAR NORMAL TEMPERATURES SHOULD OCCUR
MORE QUICKLY ON SUNDAY INTO EARLY NEXT WEEK. UPPER LEVEL RIDGE
BUILDS BACK INTO THE AREA BY TUESDAY. ANOTHER COLD FRONT LOOKS TO
BE APPROACHING THE AREA ON WEDNESDAY...BUT HAVE NOT PUT ANY POPS IN
THE FORECAST AT THIS TIME AS THE STRONG SURFACE RIDGE WHICH WILL
BRING US THIS WEEKEND`S COOL WEATHER LOOKS LIKE IT WILL LAY OUT DOWN
ACROSS THE SOUTHERN U.S. AND BLOCK ANY MOIST RETURN FLOW FROM THE
GULF.
CARNEY
&&
.AVIATION...
ISSUED AT 614 AM CDT THU SEP 6 2012
THE COLD FRONT CONTINUES TO MOVE SOUTH AND HAS PASSED THROUGH
KCOU AND KUIN. LOW LEVEL MOISTURE IS ABUNDANT AND SOME PATCHY FOG
HAS DEVELOPED...MAINLY IN LOW LYING AREAS. THIS SHOULD BURN OFF
PRETTY QUICK AFTER SUNRISE...WITH VISIBILITIES RAPIDLY IMPROVING.
CUMULUS WILL DEVELOP THIS MORNING AND INTO THE AFTERNOON AROUND
7KFT AS PLENTY OF 850MB MOISTURE REMAINS OVER THE AREA.
WIND WILL VEER FROM NORTH TO SOUTHEAST AS THE FRONT SETTLES TO OUR
SOUTH. MID LEVEL MOISTURE AND PRECIPITATION CHANCES RAPIDLY
INCREASE LATE TONIGHT AND TOMORROW MORNING AS UPPER LEVEL
DISTURBANCE MOVES TOWARD THE MIDWEST.
SPECIFICS FOR KSTL...
COLD FRONT FORECAST TO MOVE THROUGH THE TERMINAL SHORTLY AFTER 12Z
WITH WIND SWITCHING TO THE NORTH. DIURNAL SCT CU SHOULD DEVELOP
AROUND 7KFT TODAY. WIND TO VEER AROUND TO THE SOUTHEAST BY FRIDAY
MORNING...WITH PRECIPITATION CHANCES INCREASING AFTER 12Z.
CVKING
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 91 71 85 58 / 5 30 80 70
QUINCY 86 66 78 53 / 5 60 70 40
COLUMBIA 91 69 80 54 / 10 50 80 40
JEFFERSON CITY 91 69 83 56 / 10 40 80 50
SALEM 89 67 85 59 / 5 20 80 80
FARMINGTON 92 69 85 58 / 20 20 80 80
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
359 AM CDT THU SEP 6 2012
.SHORT TERM...
ISSUED AT 332 AM CDT THU SEP 6 2012
(TODAY THROUGH FRIDAY NIGHT)
STILL EATING CROW AFTER YESTERDAY`S BUSTED FORECAST...AND IT`S A
BITTER BIRD. THE COLD FRONT HAS MADE IT THROUGH KIRKSVILLE BUT IS
TAKING ITS TIME DRIFTING THROUGH THE NORTHWEST PORTION OF THE CWFA.
CURRENT THINKING IS THAT THE FRONT WILL CONTINUE DRIFTING SOUTHEAST
BUT WILL PROBABLY NOT CLEAR THE SOUTHERN PORTION OF THE CWFA BEFORE
AFTERNOON. RAP AND HRRR DEVELOP DECENT INSTABILITY IN EXCESS OF
2000 J/KG WITH LITTLE OR NO CAP. HAVE ADDED POPS SOUTH OF THE STL
METRO AREA ACROSS THE EASTERN OZARKS. ALSO...SINCE THE COLD AIR
ADVECTION IS SOMEWHAT LACKING FROM PREVIOUS FORECASTS...HAVE BUMPED
UP TEMPS A COUPLE OF DEGREES TODAY.
ATTENTION TURNS TO THE STRONG SHORTWAVE JUST NOW DROPPING INTO THE
CONUS FROM SOUTHEAST CANADA AND THE RESULTING STORM WHICH WILL MOVE
THROUGH FRIDAY AND FRIDAY NIGHT. THE WAVE`S PRESENTATION ON WATER
VAPOR IMAGERY IS PRETTY IMPRESSIVE FOR EARLY SEPTEMBER. THIS IS
ENCOURAGING FOR THE FORECAST. LATEST GUIDANCE KEEPS MUCH OF THE
AREA DRY TONIGHT...PRETTY MUCH ALL EXCEPT NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS. CAN`T QUITE BRING MYSELF TO PULL POPS OUT OF
THE REST OF THE AREA THO...SO HAVE LEFT THEM BE. ALL GUIDANCE HAS
THE SHORTWAVE DIVING INTO THE PLAINS FRIDAY MORNING AND THE
ASSOCIATED COLD FRONT MOVING THROUGH KIRKSVILLE BY AROUND 18Z. SPC
HAS US OUTLOOKED IN A SLIGHT RISK AND THIS LOOKS GOOD GIVEN THAT THE
NAM DEVELOPS INSTABILITY IN EXCESS OF 3000 J/KG AND PLENTY OF DEEP
LAYER SHEAR. HAVE BUMPED UP POPS TO OCCASIONAL DURING THE AFTERNOON
AND EARLY EVENING FOR PARTS OF THE AREA. LATEST GUIDANCE HAS THE
FRONT MOVING THOUGH FASTER THAN EARLIER FORECAST...SO HAVE CUT BACK
ON POPS AFTER MIDNIGHT.
CARNEY
&&
.LONG TERM...
ISSUED AT 358 AM CDT THU SEP 6 2012
(SATURDAY THROUGH WEDNESDAY)
PRIMARY CHANGE TO THE FORECAST FOR THE LONG TERM IS TO INCREASE HIGH
TEMPERATURES A BIT THIS WEEKEND AND EARLY NEXT WEEK. ALL OF THE
MODELS DROP A STRONG RIDGE INTO THE AREA THIS WEEKEND BEHIND THE
FRONT. WHEN WE INITIALLY BEGAN SEEING THIS STORM SYSTEM IN THE
MODELS SEVERAL DAYS AGO...THEY DEVELOPED A CLOSED LOW OVER THE GREAT
LAKES/OHIO VALLEY REGION. THE PAST FEW RUNS THE MODELS HAVE BECOME
PROGRESSIVE WITH THE WAVE. THIS SHOULD MEAN THAT INSTEAD OF
CONSIDERABLE CLOUDS AND WIDELY SCATTERED SHOWERS ON SATURDAY...IT
SHOULD BE MOSTLY SUNNY AND DRY. WITH THE MORE PROGRESSIVE
SOLUTION...THE WARM UP BACK TO NEAR NORMAL TEMPERATURES SHOULD OCCUR
MORE QUICKLY ON SUNDAY INTO EARLY NEXT WEEK. UPPER LEVEL RIDGE
BUILDS BACK INTO THE AREA BY TUESDAY. ANOTHER COLD FRONT LOOKS TO
BE APPROACHING THE AREA ON WEDNESDAY...BUT HAVE NOT PUT ANY POPS IN
THE FORECAST AT THIS TIME AS THE STRONG SURFACE RIDGE WHICH WILL
BRING US THIS WEEKEND`S COOL WEATHER LOOKS LIKE IT WILL LAY OUT DOWN
ACROSS THE SOUTHERN U.S. AND BLOCK ANY MOIST RETURN FLOW FROM THE
GULF.
CARNEY
&&
.AVIATION...
ISSUED AT 1205 AM CDT WED SEP 5 2012
ILL-DEFINED COLD FRONT HAS BEEN MOVING AT AN AGONIZINGLY SLOW
PACE THIS EVENING AND APPEARS TO HAVE JUST MOVED INTO OUR NW
COUNTIES OVER THE PAST FEW HOURS. FROPA SHOULD OCCUR AT BOTH UIN
AND COU IN THE 06-08Z TIME FRAME...AND EVENTUALLY ADVECT DRIER AIR
INTO THES AREAS. MEANWHILE...RESIDUAL MOISTURE AND RAIN-COOLED
AIRMASS HAS BEGUN TO PRODUCE FOG IN THE STL METRO AREA...AND DUE
TO THE SLOW MOVEMENT OF THE FRONT THINK THAT THIS PATCHY FOG WILL
PERSIST UNTIL AT LEAST DAYBREAK. VSBY TRENDS FOR LOW LYING
AIRPORTS (SET/SUS/CPS) HAVE BEEN TO VFR-IFR AND BACK DURING THE PAST
90 MINUTES...AND BELIEVE THESE WILD SWINGS WILL CONTINUE AT THESE
LOCATIONS DUE TO THE WAY ASOS VSBYS ARE MEASURED UNTIL DRIER AIR
ARRIVES...WHICH SHOULD BE IN THE 12-14Z TIME FRAME. CLEAR SKIES
AND LIGHT N-NE WINDS SHOULD BE THE RULE THROUGHOUT THE DAY ON
THURSDAY.
SPECIFICS FOR KSTL...
WHILE FOG WITH OCCASIONAL IFR VSBYS SHOULD HAVE ITS BIGGEST
IMPACT ON AFOREMENTIONED LOW LYING AIRPORTS (SUS/CPS)...HAVE ADDED
SOME LIGHT FOG WITH MVFR VSBYS TO STL DURING THE PREDAWN HOURS. NW
WINDS SHOULD INCREASE AROUND 12-13Z...DRAGGING DRIER AIR INTO THE
REGION AND DISSIPATING ANY LINGERING FOG.
TRUETT
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 91 71 85 58 / 5 30 80 70
QUINCY 86 66 78 53 / 5 60 70 40
COLUMBIA 91 69 80 54 / 10 50 80 40
JEFFERSON CITY 91 69 83 56 / 10 40 80 50
SALEM 89 67 85 59 / 5 20 80 80
FARMINGTON 92 69 85 58 / 20 20 80 80
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
333 AM CDT THU SEP 6 2012
.SHORT TERM...
ISSUED AT 332 AM CDT THU SEP 6 2012
(TODAY THROUGH FRIDAY NIGHT)
STILL EATING CROW AFTER YESTERDAY`S BUSTED FORECAST...AND IT`S A
BITTER BIRD. THE COLD FRONT HAS MADE IT THROUGH KIRKSVILLE BUT IS
TAKING ITS TIME DRIFTING THROUGH THE NORTHWEST PORTION OF THE CWFA.
CURRENT THINKING IS THAT THE FRONT WILL CONTINUE DRIFTING SOUTHEAST
BUT WILL PROBABLY NOT CLEAR THE SOUTHERN PORTION OF THE CWFA BEFORE
AFTERNOON. RAP AND HRRR DEVELOP DECENT INSTABILITY IN EXCESS OF
2000 J/KG WITH LITTLE OR NO CAP. HAVE ADDED POPS SOUTH OF THE STL
METRO AREA ACROSS THE EASTERN OZARKS. ALSO...SINCE THE COLD AIR
ADVECTION IS SOMEWHAT LACKING FROM PREVIOUS FORECASTS...HAVE BUMPED
UP TEMPS A COUPLE OF DEGREES TODAY.
ATTENTION TURNS TO THE STRONG SHORTWAVE JUST NOW DROPPING INTO THE
CONUS FROM SOUTHEAST CANADA AND THE RESULTING STORM WHICH WILL MOVE
THROUGH FRIDAY AND FRIDAY NIGHT. THE WAVE`S PRESENTATION ON WATER
VAPOR IMAGERY IS PRETTY IMPRESSIVE FOR EARLY SEPTEMBER. THIS IS
ENCOURAGING FOR THE FORECAST. LATEST GUIDANCE KEEPS MUCH OF THE
AREA DRY TONIGHT...PRETTY MUCH ALL EXCEPT NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS. CAN`T QUITE BRING MYSELF TO PULL POPS OUT OF
THE REST OF THE AREA THO...SO HAVE LEFT THEM BE. ALL GUIDANCE HAS
THE SHORTWAVE DIVING INTO THE PLAINS FRIDAY MORNING AND THE
ASSOCIATED COLD FRONT MOVING THROUGH KIRKSVILLE BY AROUND 18Z. SPC
HAS US OUTLOOKED IN A SLIGHT RISK AND THIS LOOKS GOOD GIVEN THAT THE
NAM DEVELOPS INSTABILITY IN EXCESS OF 3000 J/KG AND PLENTY OF DEEP
LAYER SHEAR. HAVE BUMPED UP POPS TO OCCASIONAL DURING THE AFTERNOON
AND EARLY EVENING FOR PARTS OF THE AREA. LATEST GUIDANCE HAS THE
FRONT MOVING THOUGH FASTER THAN EARLIER FORECAST...SO HAVE CUT BACK
ON POPS AFTER MIDNIGHT.
CARNEY
&&
.AVIATION...
ISSUED AT 1205 AM CDT WED SEP 5 2012
ILL-DEFINED COLD FRONT HAS BEEN MOVING AT AN AGONIZINGLY SLOW
PACE THIS EVENING AND APPEARS TO HAVE JUST MOVED INTO OUR NW
COUNTIES OVER THE PAST FEW HOURS. FROPA SHOULD OCCUR AT BOTH UIN
AND COU IN THE 06-08Z TIME FRAME...AND EVENTUALLY ADVECT DRIER AIR
INTO THES AREAS. MEANWHILE...RESIDUAL MOISTURE AND RAIN-COOLED
AIRMASS HAS BEGUN TO PRODUCE FOG IN THE STL METRO AREA...AND DUE
TO THE SLOW MOVEMENT OF THE FRONT THINK THAT THIS PATCHY FOG WILL
PERSIST UNTIL AT LEAST DAYBREAK. VSBY TRENDS FOR LOW LYING
AIRPORTS (SET/SUS/CPS) HAVE BEEN TO VFR-IFR AND BACK DURING THE PAST
90 MINUTES...AND BELIEVE THESE WILD SWINGS WILL CONTINUE AT THESE
LOCATIONS DUE TO THE WAY ASOS VSBYS ARE MEASURED UNTIL DRIER AIR
ARRIVES...WHICH SHOULD BE IN THE 12-14Z TIME FRAME. CLEAR SKIES
AND LIGHT N-NE WINDS SHOULD BE THE RULE THROUGHOUT THE DAY ON
THURSDAY.
SPECIFICS FOR KSTL...
WHILE FOG WITH OCCASIONAL IFR VSBYS SHOULD HAVE ITS BIGGEST
IMPACT ON AFOREMENTIONED LOW LYING AIRPORTS (SUS/CPS)...HAVE ADDED
SOME LIGHT FOG WITH MVFR VSBYS TO STL DURING THE PREDAWN HOURS. NW
WINDS SHOULD INCREASE AROUND 12-13Z...DRAGGING DRIER AIR INTO THE
REGION AND DISSIPATING ANY LINGERING FOG.
TRUETT
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 91 71 85 58 / 5 30 80 70
QUINCY 86 66 78 53 / 5 60 70 40
COLUMBIA 91 69 80 54 / 10 50 80 40
JEFFERSON CITY 91 69 83 56 / 10 40 80 50
SALEM 89 67 85 59 / 5 20 80 80
FARMINGTON 92 69 85 58 / 20 20 80 80
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1247 PM CDT THU SEP 6 2012
.AVIATION...
VFR IS EXPECTED ALL AREAS THROUGH 06Z THIS EVENING.
06Z-12Z TONIGHT...THEREAFTER A STRONG COLD FRONT MAY BE SUFFICIENT
FOR MVFR CIGS AND LIGHT RAIN ALONG AND NORTH OF NEBRASKA HIGHWAY
2...POSSIBLY OVER THE KVTN TERMINAL. THE AMOUNT OF MOISTURE
RETURN IS IN QUESTION...THUS DID NOT HAVE HIGH ENOUGH CONFIDENCE TO
MENTION A PREVAILING PRECIPITATION GROUP...BUT WILL INTRODUCE A
PROB30 AT KVTN FROM 09-12Z. OTHERWISE THE MAIN CONCERN TO THE
AVIATION COMMUNITY FOR THE NEXT 24 HOURS WILL BE THE EXPECTED
INCREASE IN WIND SPEEDS BEHIND THE FRONT. MODEL GUIDANCE INDICATES
GUSTS AT OR EXCEEDING 20KTS BEHIND AND SEVERAL HOURS BEHIND THE
FRONT
&&
PREV DISCUSSION... /ISSUED 437 AM CDT THU SEP 6 2012/
UPDATE...
FIRE WEATHER...
THE RFW PRODUCT HAS BEEN UPDATED FOR A WIND SHIFT DEVELOPING
AROUND 18Z PER RAP AND HRRR MODELS. THOSE MODELS ARE CONSOLIDATING
LOW PRESSURE ALONG THE ND/SD BORDER AND SENDING A "COLD" FRONT
INTO NRN NEB. THIS IS ABOUT 3 HOURS FASTER THAN THE OTHER OPERATIONAL
MODELS.
PREV DISCUSSION... /ISSUED 350 AM CDT THU SEP 6 2012/
DISCUSSION...
PRIMARY FORECAST CONCERNS FOR THIS FORECAST ARE FIRE WEATHER
CONCERNS TODAY...HIGHS TODAY...AS WELL AS TEMPERATURES AND RAIN
CHANCES SURROUNDING FRONTAL PASSAGE FRIDAY.
UPPER LEVEL ANALYSIS SHOWED LOW PRESSURE OVER NORTHERN
MANITOBA...WITH ONE SHORTWAVE TROUGH EXTENDING INTO THE GREAT
LAKES...AND A SECOND SHORTWAVE TROUGH EXTENDING INTO THE PACIFIC
NORTHWEST. THIS SECOND SYSTEM IS SHOWING THE STRONGEST ENERGY OVER
SOUTHERN BRITISH COLUMBIA MOVING INTO IDAHO AND MONTANA EARLY THIS
MORNING. ALSO...BROAD RIDGING SEEN ALOFT OVER THE SOUTHERN US.
THIS PATTERN LEADS TO FAIRLY ZONAL/NORTHWEST FLOW INTO THE LOCAL
FORECAST AREA CURRENTLY. THIS FLOW IS BRINGING A GOOD AMOUNT OF
SMOKE INTO THE CENTRAL PLAINS FROM FIRES OVER IDAHO AND WYOMING.
AT THE SURFACE...LOW PRESSURE OBSERVED OVER NORTHWEST SOUTH DAKOTA
WITH A COLD FRONT EXTENDING ACROSS NORTHERN WYOMING AND INTO
WESTERN MONTANA. ALSO...A SURFACE TROUGH WAS SEEN FROM WESTERN
SOUTH DAKOTA INTO THE NEBRASKA PANHANDLE...WITH THE AXIS OF HIGH
PRESSURE FROM NORTHWEST KANSAS INTO NORTHEAST NEBRASKA. UNDER THE
SURFACE HIGH...TEMPERATURES HAD DROPPED INTO THE 40S...WHILE
CLOSER TO THE TROUGH WHERE THE BOUNDARY LAYER HAD STAYED
MIXED...UPPER 60S WERE BEING OBSERVED.
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
THE SHORTWAVE TROUGH OVER IDAHO/MONTANA WILL MOVE SOUTHEAST
ACROSS THE NORTHERN ROCKIES TODAY. THIS WILL KEEP THE FLOW QUITE
FLAT ACROSS THE CENTRAL AND NORTHERN PARTS OF THE COUNTRY...SO
WILL EXPECT TO CONTINUE TO SEE QUITE A BIT OF SMOKE IN THE SKY
THROUGH THE DAY TOMORROW. AS THE UPPER LEVEL SYSTEM MOVES
SOUTH...SO WILL THE COLD FRONT CURRENTLY OVER WYOMING. AHEAD OF
THE FRONT...THE SURFACE TROUGH/DRYLINE OVER THE NEBRASKA PANHANDLE
WILL SURGE EAST BRINGING VERY DRY AIR INTO THE FORECAST AREA. THE
NAM HAS BEEN PERFORMING BEST LATELY IN TERMS OF DEWPOINTS SO FELT
CONFIDENT IN GOING TOWARDS THAT MODEL FOR THE FORECAST TODAY. THIS
WOULD BRING 20 DEGREE DEWPOINTS INTO THE WESTERN PARTS OF THE
FORECAST AREA...WHICH LOOKS REASONABLE AS MUCH OF WYOMING AND
NORTHERN COLORADO ARE OBSERVING VALUES IN THE TEENS CURRENTLY.
THIS DRY AIR WILL HELP TO CREATE DEEP MIXING THIS AFTERNOON...AND
WHEN COMBINED WITH WARM AIR ADVECTION WITH THE HIGH MOVING OFF TO
THE EAST WENT ON THE HIGH END FOR TEMPERATURES TODAY. ALSO...HAVE
BEEN OBSERVING VERY LARGE DIURNAL SWINGS IN TEMPERATURES...SO
ALTHOUGH LOWS WILL BE IN THE 40S FOR SOME PLACES...DON/T SEE A
PROBLEM WITH REACHING THE MID 90S THIS AFTERNOON. PLACES OVER
NORTHWEST NEBRASKA WILL BE A BIT MORE TRICKY FOR HIGH TEMPERATURES
AS THE FRONT WILL PASS THROUGH THESE AREAS THIS AFTERNOON.
ALTHOUGH WILL LIKELY NOT SEE AS HOT OF TEMPERATURES IN THOSE
LOCATIONS...NOT GOING TO SEE THE COLD AIR PUSH INTO NEBRASKA
UNTIL EVENING AND OVERNIGHT SO STILL EXPECTING HIGHS IN THE UPPER
80S. BREEZY WINDS AND ALONG WITH A WINDSHIFT WITH THE
FRONT...COMBINED WITH THE HEAT AND VERY DRY CONDITIONS FIRE
WEATHER CONDITIONS WILL BE OF HIGH CONCERN. SEE DETAILED
DISCUSSION BELOW.
CONTINUED THE SLIGHT CHANCES FOR THUNDERSTORMS IN THE FAR EASTERN
COUNTIES LATER THIS AFTERNOON AND EVENING AS DEVELOPMENT IS
EXPECTED ALONG AND EAST OF THE DRYLINE. PROBABILITIES ARE BEST
EAST OF THE FORECAST AREA...BUT IF THE DRY AIR DOESN/T ADVANCE AS
FAR EAST...THE AREA OF CONCERN WILL SHIFT. ANY STORMS THAT DO
DEVELOP ON THIS LINE WILL HAVE THE POTENTIAL TO BE STRONG TO
SEVERE WITH FAVORABLE SHEAR AND INSTABILITY EXPECTED.
TONIGHT...BREEZY CONDITIONS ARE EXPECTED AS THE FRONT PUSHES
SOUTH. ALTHOUGH COLDER AIR WILL BE PUSHING IN BEHIND THE
FRONT...THE WINDS AND GOOD AMOUNT OF CLOUD COVER WILL PROHIBIT
TEMPERATURES FROM FALLING TOO MUCH. ALSO...THERE WILL BE CHANCES
FOR RAIN TONIGHT. AREAS WITH THE HIGHER CHANCE FOR RAIN WILL BE
OVER NORTHERN NEBRASKA AFTER MIDNIGHT AS STRONGER LIFT WILL BE
OVER THE AREA AT THAT TIME...WITH THE FRONT AND THE UPPER LEVEL
ENERGY PUSHING THROUGH. THESE CHANCES WILL SHIFT SOUTH FRIDAY
MORNING...HOWEVER DYNAMICS DOESN/T LOOK AS GOOD SO ONLY HAVE A
SLIGHT CHANCE THROUGH 18Z ACROSS THE FORECAST AREA. ALTHOUGH
DYNAMICALLY...IT LOOKS FAVORABLE FOR SHOWERS...LOW LEVEL MOISTURE
WILL BE A LIMITING FACTOR. THE NAM IS SHOWING MOISTURE IMPROVING
WITH PRECIPITABLE WATER INCREASING TO NEAR AN INCH ALONG THE
FRONT...BUT DON/T KNOW IF THERE WILL BE THAT MUCH MOISTURE
ADVECTION BETWEEN NOW AND THEN. LATEST KLBF SOUNDING HAD PW OF
0.38 INCHES. CROSS-SECTIONS ALSO SUGGESTING THE COLUMN WILL NEARLY
SATURATE. DON/T WANT TO DISCOUNT THIS...BUT LOOKING AT THIS SYSTEM
OVER MONTANA CURRENTLY...MOST CEILINGS ARE ABOVE 5K FEET. WILL
CONTINUE TO WATCH THE SYSTEM CLOSELY...BUT FEELING IS ANY RAINFALL
WILL BE LIGHT WITH LITTLE ACCUMULATIONS /LESS THAN A TENTH OF AN
INCH/ EXPECTED.
WITH THE CLOUDY SKIES AND COLD AIR MOVING INTO THE AREA BEHIND THE
FRONT...FRIDAY SHOULD BE A MUCH COOLER DAY. LOOKING AT HIGHS ONLY
IN THE UPPER 60S AND 70S. HOWEVER...BIG STORY WILL BE LOWS FRIDAY
NIGHT. WITH HIGH PRESSURE SETTLING IN...SKIES SHOULD CLEAR AND
WINDS ARE EXPECTED TO BECOME LIGHT OR CALM. THESE CONDITIONS WILL
PROMOTE RADIATIONAL COOLING...AND WITH THE DRY AIRMASS IN PLACE
/DEWPOINTS IN THE 30S/...EXPECT A COLD NIGHT ACROSS WESTERN
NEBRASKA. DROPPED LOWS TEMPERATURES...WITH LOCATIONS IN VALLEYS OR
OTHER FAVORED DRAINAGE AREAS FALLING INTO THE 30S. WILL BE CLOSELY
WATCHING THIS IN COMING FORECASTS AS LOWS IN THE 30S COULD MEAN
THE DEVELOPMENT OF FROST IN AREAS.
LOOKING TO SATURDAY...HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE
AREA. HOWEVER...WARM AIR ADVECTION WILL BE ONGOING ALOFT. GOOD
MIXING AND SUNSHINE WILL ALLOW FOR TEMPERATURES TO WARM BACK TO
NEAR NORMAL VALUES AROUND 80 DEGREES.
LONG TERM...SUNDAY THROUGH WEDNESDAY
TEMPERATURES WILL BE ON THE RISE SUNDAY AND MONDAY...WITH
POTENTIAL SHOWING UP FOR ANOTHER HOT DAY ON MONDAY. HAVE LOW 90S
IN THE FORECAST CURRENTLY BUT MAY NEED TO ADJUST THOSE NUMBERS UP
IN COMING FORECASTS. ANOTHER COLD FRONT IS PROJECTED TO MOVE
THROUGH THE FORECAST AREA ON TUESDAY. TIMING IS A BIT PROBLEMATIC
AT THIS TIME...WHICH WILL HAVE IMPACT ON TEMPERATURES FOR TUESDAY.
ANOTHER PUSH OF COLD AIR WILL COME INTO THE AREA BEHIND THIS
FRONT...SO WEDNESDAY IS LOOKING TO BE A DAY WITH HIGHS IN THE 70S.
IN TERMS OF RAINFALL...THE FORECAST REMAINS DRY AS MODELS ARE
SHOWING DRY AIR CONTINUING TO BE DOMINANT SO DON/T HAVE A GOOD
HANDLE IF ANY SHOWERS/STORMS WILL DEVELOP ALONG THE FRONT.
CONSENSUS FROM THE CURRENT MODELS INDICATES THE FRONT WILL PASS BY
DRY FOR THE MOST PART WITH MAYBE A FEW ISOLATED STORMS.
WILL CONTINUE TO KEEP THE FORECAST DRY UNLESS MODELS START SHOWING
BETTER SIGNALS FOR PRECIPITATION DEVELOPMENT.
FIRE WEATHER...
ARF...NMM AND NAM SOLNS SHOW RH FALLING TO BETWEEN 5 AND 7 PERCENT
ACROSS WRN NEB. THE OFFICIAL FORECAST IS FOR 8 TO 10 PERCENT RH AND
WIND GUSTS TO AROUND 30 MPH. THUS A BIG FIRE DAY IS EXPECTED. DPTS
ACROSS WY ARE IN THE TEENS WITH RH AS LOW AS 18 PERCENT AT LANDER
AND RIVERTON AT 07Z.
A RED FLAG WARNING IS IN EFFECT FOR ALL ZONES TODAY.
OTHER OPPORTUNITIES FOR CRITICAL FIRE DANGER COULD DEVELOP SUNDAY
ACROSS THE WRN HIGH PLAINS AS LOW PRESSURE DEEPENS ACROSS THE NRN
HIGH PLAINS. ALSO MONDAY COULD BE A BIG FIRE DAY FOR ALL AREAS AS A
LOW PRESSURE TROF MOVES EAST THROUGH THE CNTL AND NRN PLAINS.
CONCERNS CONTINUE TUESDAY AS DRY AIR WILL BE MOVING SWIFTLY SOUTH
BEHIND A COLD FRONT PROGGED TO MOVE THROUGH MONDAY NIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING UNTIL 10 PM CDT
/9 PM MDT/ THIS EVENING FOR NEZ204-206-208>210-219.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
437 AM CDT THU SEP 6 2012
.UPDATE...
.FIRE WEATHER...
THE RFW PRODUCT HAS BEEN UPDATED FOR A WIND SHIFT DEVELOPING
AROUND 18Z PER RAP AND HRRR MODELS. THOSE MODELS ARE CONSOLIDATING
LOW PRESSURE ALONG THE ND/SD BORDER AND SENDING A "COLD" FRONT
INTO NRN NEB. THIS IS ABOUT 3 HOURS FASTER THAN THE OTHER OPERATIONAL
MODELS.
&&
.PREV DISCUSSION... /ISSUED 350 AM CDT THU SEP 6 2012/
DISCUSSION...
PRIMARY FORECAST CONCERNS FOR THIS FORECAST ARE FIRE WEATHER
CONCERNS TODAY...HIGHS TODAY...AS WELL AS TEMPERATURES AND RAIN
CHANCES SURROUNDING FRONTAL PASSAGE FRIDAY.
UPPER LEVEL ANALYSIS SHOWED LOW PRESSURE OVER NORTHERN
MANITOBA...WITH ONE SHORTWAVE TROUGH EXTENDING INTO THE GREAT
LAKES...AND A SECOND SHORTWAVE TROUGH EXTENDING INTO THE PACIFIC
NORTHWEST. THIS SECOND SYSTEM IS SHOWING THE STRONGEST ENERGY OVER
SOUTHERN BRITISH COLUMBIA MOVING INTO IDAHO AND MONTANA EARLY THIS
MORNING. ALSO...BROAD RIDGING SEEN ALOFT OVER THE SOUTHERN US.
THIS PATTERN LEADS TO FAIRLY ZONAL/NORTHWEST FLOW INTO THE LOCAL
FORECAST AREA CURRENTLY. THIS FLOW IS BRINGING A GOOD AMOUNT OF
SMOKE INTO THE CENTRAL PLAINS FROM FIRES OVER IDAHO AND WYOMING.
AT THE SURFACE...LOW PRESSURE OBSERVED OVER NORTHWEST SOUTH DAKOTA
WITH A COLD FRONT EXTENDING ACROSS NORTHERN WYOMING AND INTO
WESTERN MONTANA. ALSO...A SURFACE TROUGH WAS SEEN FROM WESTERN
SOUTH DAKOTA INTO THE NEBRASKA PANHANDLE...WITH THE AXIS OF HIGH
PRESSURE FROM NORTHWEST KANSAS INTO NORTHEAST NEBRASKA. UNDER THE
SURFACE HIGH...TEMPERATURES HAD DROPPED INTO THE 40S...WHILE
CLOSER TO THE TROUGH WHERE THE BOUNDARY LAYER HAD STAYED
MIXED...UPPER 60S WERE BEING OBSERVED.
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
THE SHORTWAVE TROUGH OVER IDAHO/MONTANA WILL MOVE SOUTHEAST
ACROSS THE NORTHERN ROCKIES TODAY. THIS WILL KEEP THE FLOW QUITE
FLAT ACROSS THE CENTRAL AND NORTHERN PARTS OF THE COUNTRY...SO
WILL EXPECT TO CONTINUE TO SEE QUITE A BIT OF SMOKE IN THE SKY
THROUGH THE DAY TOMORROW. AS THE UPPER LEVEL SYSTEM MOVES
SOUTH...SO WILL THE COLD FRONT CURRENTLY OVER WYOMING. AHEAD OF
THE FRONT...THE SURFACE TROUGH/DRYLINE OVER THE NEBRASKA PANHANDLE
WILL SURGE EAST BRINGING VERY DRY AIR INTO THE FORECAST AREA. THE
NAM HAS BEEN PERFORMING BEST LATELY IN TERMS OF DEWPOINTS SO FELT
CONFIDENT IN GOING TOWARDS THAT MODEL FOR THE FORECAST TODAY. THIS
WOULD BRING 20 DEGREE DEWPOINTS INTO THE WESTERN PARTS OF THE
FORECAST AREA...WHICH LOOKS REASONABLE AS MUCH OF WYOMING AND
NORTHERN COLORADO ARE OBSERVING VALUES IN THE TEENS CURRENTLY.
THIS DRY AIR WILL HELP TO CREATE DEEP MIXING THIS AFTERNOON...AND
WHEN COMBINED WITH WARM AIR ADVECTION WITH THE HIGH MOVING OFF TO
THE EAST WENT ON THE HIGH END FOR TEMPERATURES TODAY. ALSO...HAVE
BEEN OBSERVING VERY LARGE DIURNAL SWINGS IN TEMPERATURES...SO
ALTHOUGH LOWS WILL BE IN THE 40S FOR SOME PLACES...DON/T SEE A
PROBLEM WITH REACHING THE MID 90S THIS AFTERNOON. PLACES OVER
NORTHWEST NEBRASKA WILL BE A BIT MORE TRICKY FOR HIGH TEMPERATURES
AS THE FRONT WILL PASS THROUGH THESE AREAS THIS AFTERNOON.
ALTHOUGH WILL LIKELY NOT SEE AS HOT OF TEMPERATURES IN THOSE
LOCATIONS...NOT GOING TO SEE THE COLD AIR PUSH INTO NEBRASKA
UNTIL EVENING AND OVERNIGHT SO STILL EXPECTING HIGHS IN THE UPPER
80S. BREEZY WINDS AND ALONG WITH A WINDSHIFT WITH THE
FRONT...COMBINED WITH THE HEAT AND VERY DRY CONDITIONS FIRE
WEATHER CONDITIONS WILL BE OF HIGH CONCERN. SEE DETAILED
DISCUSSION BELOW.
CONTINUED THE SLIGHT CHANCES FOR THUNDERSTORMS IN THE FAR EASTERN
COUNTIES LATER THIS AFTERNOON AND EVENING AS DEVELOPMENT IS
EXPECTED ALONG AND EAST OF THE DRYLINE. PROBABILITIES ARE BEST
EAST OF THE FORECAST AREA...BUT IF THE DRY AIR DOESN/T ADVANCE AS
FAR EAST...THE AREA OF CONCERN WILL SHIFT. ANY STORMS THAT DO
DEVELOP ON THIS LINE WILL HAVE THE POTENTIAL TO BE STRONG TO
SEVERE WITH FAVORABLE SHEAR AND INSTABILITY EXPECTED.
TONIGHT...BREEZY CONDITIONS ARE EXPECTED AS THE FRONT PUSHES
SOUTH. ALTHOUGH COLDER AIR WILL BE PUSHING IN BEHIND THE
FRONT...THE WINDS AND GOOD AMOUNT OF CLOUD COVER WILL PROHIBIT
TEMPERATURES FROM FALLING TOO MUCH. ALSO...THERE WILL BE CHANCES
FOR RAIN TONIGHT. AREAS WITH THE HIGHER CHANCE FOR RAIN WILL BE
OVER NORTHERN NEBRASKA AFTER MIDNIGHT AS STRONGER LIFT WILL BE
OVER THE AREA AT THAT TIME...WITH THE FRONT AND THE UPPER LEVEL
ENERGY PUSHING THROUGH. THESE CHANCES WILL SHIFT SOUTH FRIDAY
MORNING...HOWEVER DYNAMICS DOESN/T LOOK AS GOOD SO ONLY HAVE A
SLIGHT CHANCE THROUGH 18Z ACROSS THE FORECAST AREA. ALTHOUGH
DYNAMICALLY...IT LOOKS FAVORABLE FOR SHOWERS...LOW LEVEL MOISTURE
WILL BE A LIMITING FACTOR. THE NAM IS SHOWING MOISTURE IMPROVING
WITH PRECIPITABLE WATER INCREASING TO NEAR AN INCH ALONG THE
FRONT...BUT DON/T KNOW IF THERE WILL BE THAT MUCH MOISTURE
ADVECTION BETWEEN NOW AND THEN. LATEST KLBF SOUNDING HAD PW OF
0.38 INCHES. CROSS-SECTIONS ALSO SUGGESTING THE COLUMN WILL NEARLY
SATURATE. DON/T WANT TO DISCOUNT THIS...BUT LOOKING AT THIS SYSTEM
OVER MONTANA CURRENTLY...MOST CEILINGS ARE ABOVE 5K FEET. WILL
CONTINUE TO WATCH THE SYSTEM CLOSELY...BUT FEELING IS ANY RAINFALL
WILL BE LIGHT WITH LITTLE ACCUMULATIONS /LESS THAN A TENTH OF AN
INCH/ EXPECTED.
WITH THE CLOUDY SKIES AND COLD AIR MOVING INTO THE AREA BEHIND THE
FRONT...FRIDAY SHOULD BE A MUCH COOLER DAY. LOOKING AT HIGHS ONLY
IN THE UPPER 60S AND 70S. HOWEVER...BIG STORY WILL BE LOWS FRIDAY
NIGHT. WITH HIGH PRESSURE SETTLING IN...SKIES SHOULD CLEAR AND
WINDS ARE EXPECTED TO BECOME LIGHT OR CALM. THESE CONDITIONS WILL
PROMOTE RADIATIONAL COOLING...AND WITH THE DRY AIRMASS IN PLACE
/DEWPOINTS IN THE 30S/...EXPECT A COLD NIGHT ACROSS WESTERN
NEBRASKA. DROPPED LOWS TEMPERATURES...WITH LOCATIONS IN VALLEYS OR
OTHER FAVORED DRAINAGE AREAS FALLING INTO THE 30S. WILL BE CLOSELY
WATCHING THIS IN COMING FORECASTS AS LOWS IN THE 30S COULD MEAN
THE DEVELOPMENT OF FROST IN AREAS.
LOOKING TO SATURDAY...HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE
AREA. HOWEVER...WARM AIR ADVECTION WILL BE ONGOING ALOFT. GOOD
MIXING AND SUNSHINE WILL ALLOW FOR TEMPERATURES TO WARM BACK TO
NEAR NORMAL VALUES AROUND 80 DEGREES.
LONG TERM...SUNDAY THROUGH WEDNESDAY
TEMPERATURES WILL BE ON THE RISE SUNDAY AND MONDAY...WITH
POTENTIAL SHOWING UP FOR ANOTHER HOT DAY ON MONDAY. HAVE LOW 90S
IN THE FORECAST CURRENTLY BUT MAY NEED TO ADJUST THOSE NUMBERS UP
IN COMING FORECASTS. ANOTHER COLD FRONT IS PROJECTED TO MOVE
THROUGH THE FORECAST AREA ON TUESDAY. TIMING IS A BIT PROBLEMATIC
AT THIS TIME...WHICH WILL HAVE IMPACT ON TEMPERATURES FOR TUESDAY.
ANOTHER PUSH OF COLD AIR WILL COME INTO THE AREA BEHIND THIS
FRONT...SO WEDNESDAY IS LOOKING TO BE A DAY WITH HIGHS IN THE 70S.
IN TERMS OF RAINFALL...THE FORECAST REMAINS DRY AS MODELS ARE
SHOWING DRY AIR CONTINUING TO BE DOMINANT SO DON/T HAVE A GOOD
HANDLE IF ANY SHOWERS/STORMS WILL DEVELOP ALONG THE FRONT.
CONSENSUS FROM THE CURRENT MODELS INDICATES THE FRONT WILL PASS BY
DRY FOR THE MOST PART WITH MAYBE A FEW ISOLATED STORMS.
WILL CONTINUE TO KEEP THE FORECAST DRY UNLESS MODELS START SHOWING
BETTER SIGNALS FOR PRECIPITATION DEVELOPMENT.
AVIATION...
VFR IS EXPECTED ALL AREAS THROUGH 06Z THIS EVENING.
06Z-12Z TONIGHT...THEREAFTER A STRONG COLD FRONT MAY BE SUFFICIENT
FOR MVFR CIGS AND LIGHT RAIN ALONG AND NORTH OF NEBRASKA HIGHWAY 2.
LATER FORECASTS CAN VERIFY THE RELIABILITY OF THIS FCST AS LOW LEVEL
MOISTURE MAY BE A LIMITING FACTOR.
FIRE WEATHER...
ARF...NMM AND NAM SOLNS SHOW RH FALLING TO BETWEEN 5 AND 7 PERCENT
ACROSS WRN NEB. THE OFFICIAL FORECAST IS FOR 8 TO 10 PERCENT RH AND
WIND GUSTS TO AROUND 30 MPH. THUS A BIG FIRE DAY IS EXPECTED. DPTS
ACROSS WY ARE IN THE TEENS WITH RH AS LOW AS 18 PERCENT AT LANDER
AND RIVERTON AT 07Z.
A RED FLAG WARNING IS IN EFFECT FOR ALL ZONES TODAY.
OTHER OPPORTUNITIES FOR CRITICAL FIRE DANGER COULD DEVELOP SUNDAY
ACROSS THE WRN HIGH PLAINS AS LOW PRESSURE DEEPENS ACROSS THE NRN
HIGH PLAINS. ALSO MONDAY COULD BE A BIG FIRE DAY FOR ALL AREAS AS A
LOW PRESSURE TROF MOVES EAST THROUGH THE CNTL AND NRN PLAINS.
CONCERNS CONTINUE TUESDAY AS DRY AIR WILL BE MOVING SWIFTLY SOUTH
BEHIND A COLD FRONT PROGGED TO MOVE THROUGH MONDAY NIGHT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 10 PM CDT /9
PM MDT/ THIS EVENING FOR NEZ204-206-208>210-219.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS ELKO NV
303 PM PDT THU SEP 6 2012
.SYNOPSIS...LOW PRESSURE SYSTEM BRINGS PARTLY TO MOSTLY CLOUDY
SKIES TO NORTHERN AND CENTRAL NEVADA THIS AFTERNOON AND EVENING.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED OVER WHITE PINE
COUNTY THIS AFTERNOON. FRIDAY AND SATURDAY WILL BE MILD AND DRY.
NEXT ROUND OF THUNDERSTORMS EXPECTED SUNDAY AFTERNOON.
&&
.SHORT TERM...TONIGHT THROUGH FRIDAY. THE REMNANTS OF A PACIFIC
LOW ARE PUSHING ACROSS THE GREAT BASIN BRINGING CLOUD
COVERAGE...SLIGHTLY COOLER TEMPS AND A BAND OF CONVECTION TO
PORTIONS OF CENTRAL NEVADA...NAMELY WHITE PINE COUNTY. NUMEROUS
LIGHTNING STRIKES AND PEA SIZED HAIL HAVE ALREADY BEEN OBSERVED
FROM SOUTHEASTERN ELKO COUNTY TO LUND ALONG A NORTHEAST TO
SOUTHWEST ORIENTED AXIS. THE NAM12 AND HRRR PINGED INTO UNSTABLE
CONDITIONS OVER CENTRAL NEVADA...DEPICTING +400 J/KG OVER WHITE
PINE AND THE EASTERN PORTION OF NORTHERN NYE COINCIDENT WITH
NEGATIVE LIFTED INDICES. MORE CONVECTION ON TAP FOR TONIGHT. THE
NAM12 AND THE GFS40 ARE BOTH DRIER AND SLIGHTLY MORE STABLE
TOMORROW...AS THE RIDGE AXIS BUILDS BACK INTO THE LKN CWA.
.LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY. LOW PRESSURE SYSTEM
OFF PACIFIC NORTHWEST COAST. HIGH PRESSURE RIDGE OVER GREAT BASIN.
LONG RANGE MODELS HAVE THE LOW TRACKING NORTH UP THE COAST BEFORE
BEING KICKED NORTHEAST LATE SATURDAY. THIS WILL RESULT IN RELATIVELY
DRY AIR FRIDAY NIGHT AND SATURDAY OVER THE GREAT BASIN WITH RIDGE
AXIS OVERHEAD. WHEN THE LOW KICKS OUT...THE RIDGE FIRST
FLATTENS...THEN DRIFTS EAST ON SUNDAY. THIS WILL OPEN UP MOISTURE
FROM THE SUB-TROPICS TO MOVE NORTH INTO NEVADA...ESPECIALLY OVER THE
SOUTHEAST HALF OF THE FORECAST AREA ON SATURDAY NIGHT THROUGH
TUESDAY.
TEMPS WILL START NEAR 90 AT MOST VALLEY LOCATIONS...DROPPING TO NEAR
NORMAL...THE 80S...BY EARLY IN THE WEEK. LOW TEMPS WILL START IN THE
50S...AND END UP IN THE 40S IN THE POPULATED VALLEY LOCATIONS. A FEW
30S COULD CREEP IN AS SKIES CLEAR OUT MID WEEK.
&&
.AVIATION...SCT/BKN MID CLOUDS ACROSS NEVADA THROUGH 03Z FRI. AREA
OF CONVERGING WINDS WILL FIRE UP THUNDERSTORMS IN WHITE PINE COUNTY
AND AFFECT KELY THROUGH SUNSET. SOME SHOWERS MAY AFFECT KEKO. KWMC
AND KTPH SHOULD REMAIN STORM FREE. GUSTY WINDS AT ALL BUT KEKO WILL
REDUCE CLOUD COVER AFTER SUNSET AND ON FRIDAY.
&&
.FIRE WEATHER...THIS AFTERNOON THUNDERSTORM ACTIVITY WILL BE
CONCENTRATED OVER 455 AS A WELL DEFINED BAND MOVES THROUGH. THE
PWS HAVE BEEN OVER .80 OF AN INCH IN 455 ON THE
MODELS...SUFFICIENT TO PRODUCE WETTING RAINS. NUMEROUS LIGHTNING
STRIKES ALREADY OBSERVED OVER WHITE PINE COUNTY TODAY. MOSTLY DRY
AND MILD CONDITIONS EXPECTED FRIDAY AND SATURDAY. NEXT WAVE OF
THUNDERSTORM ACTIVITY EXPECTED SUNDAY AND MONDAY AFTERNOONS.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
97/98/98/97
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
147 PM EDT THU SEP 6 2012
.SYNOPSIS...
WEAK COLD FRONT DISSIPATES THIS EVENING. HIGH PRESSURE FRIDAY. STRONG
COLD FRONT SATURDAY. HIGH PRESSURE SUNDAY INTO THE NEXT WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE...NO SIGNIFICANT CHANGES.
600AM UPDATE...
NO SIGNIFICANT CHANGES MADE WITH THIS UPDATE...JUST TWEAKED
INITIAL SKY GRIDS.
PREVIOUS DISCUSSION BELOW...
SHRA CONT TO INCREASE ACROSS N CARTER AND S GREENUP AS OF
0630Z...WITH NEARLY STATIONARY MOTIONS. BUMPED UP POPS INTO LKLY
NEXT COUPLE HRS ACROSS NE KY COUNTIES. WILL BE MONITORING RAINFALL
AS WELL.
PREVIOUS DISCUSSION BELOW...
SHRA LIGHTING UP ON RADAR AT 06Z ACROSS W ZONES...ASSOCIATED WITH
S/W TROF AND EMBEDDED VORT MAX. RUC TRACKS THIS SLOWLY NE THRU CWA
BY 13Z. HAVE SOME LOW POPS WITH THIS AS IT DOES SO. BACK EDGE OF
CLDS WILL SLOWLY PUSH THRU PORTIONS OF SE OH BY 08Z...TAKING TO
NEAR SUNRISE TO GET INTO CENTRAL WV LOWLANDS. FURTHER COMPLICATING
SKY COVER IS LOW STRATUS THAT IS POISED TO DEVELOP ACROSS ALONG
AND E OF I79 CORRIDOR...BASED ON MODEL PROJECTIONS. THINK THIS MAY
END UP MORE IN MTNS AND S COAL FIELDS. SOME RVR VALLEY FG THROWN
IN AS WELL...ESPECIALLY FOR AREAS THAT MANAGE TO CLR.
WILL TRY TO SCT OUT ANY LOW CLDS BY MID MORNING. WILL LOOK FOR MTN
SHRA AND A FEW TSRA TO DEVELOP WITH HEATING AND WEAK OROGRAPHIC
LIFT. WILL CARRY CHC POPS THERE...TAILING OFF TO SCHC BACK TO I79
CORRIDOR. OTHERWISE...WEAK FRONT DROPPING SE THRU UPR OH VALLEY
LOOKS TO BE DELAYED UNTIL LATE AFTN FOR SE OH ZONES BEFORE BECOMING
RATHER DIFFUSE TONIGHT. HAVE ONLY SCHC POPS WITH THIS AS OVERALL
SETUP LOOKS RATHER MEAGER.
WILL ROLL A TICK OR TWO ABV WARMEST GUIDANCE FOR HIGHS TDY BASED
ON RECENT PERFORMANCE AND NEAR HIGH SIDE OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
MODELS HAVE COME INTO DECENT AGREEMENT THROUGHOUT THE PERIOD. MODELS
SHOW HIGH PRESSURE FOR FRIDAY. MESO NAM IS TRYING TO CREATE A FEW
SHOWERS IN THE MOUNTAINS...BUT BELIEVE THAT THE 700 MB AIR IS TOO
DRY. A FAST MOVING COLD FRONT THEN PUSHES THROUGH ON SATURDAY. WILL
FINE TUNE POPS FOR BETTER TIMING. HIGH PRESSURE THEN TAKES OVER
SATURDAY NIGHT INTO THE NEXT WORK WEEK. WILL REMOVE POPS SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
MADE WHOLESALE CHANGES TO THE LONG TERM FORECAST AS MODELS COMING
INTO BETTER AGREEMENT THAN YESTERDAY...NOW SHOWING OPEN WAVE
SWINGING THROUGH OVER THE WEEKEND...AND A THING OF THE PAST AS WE
HEAD INTO THE WORK WEEK. LINGER CHANCE AND SLIGHT CHANCE POPS
THROUGH SUNDAY...MOVING OUT SUNDAY NIGHT AS THE UPPER TROUGH MOVES
EAST AND OUT TO SEA. THIS WILL PROVIDE A MAINLY DRY FORECAST FOR THE
REST OF THE LONG TERM. DID NOT INCLUDE ANY POPS FOR THE WORK WEEK AT
THIS TIME DUE TO LACKING MOISTURE...BUT WITH NORTHWEST FLOW IT MAY
BE POSSIBLE TO GET A LITTLE SHORTWAVE RIPPLE THAT COULD POP A SHOWER
OR TWO AT SOME POINT. TEMPERATURES WILL START OFF BELOW NORMAL ON
MONDAY...WITH A GRADUAL WARMING TREND TO NEAR NORMAL BY MID TO LATE
WEEK AS UPPER RIDGE MOVES INTO SOUTHERN PLAINS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z THURSDAY THRU 18Z FRIDAY...
A WEAK DRY COLD WILL DISSIPATE AS IT COMES INTO NORTHERN PORTIONS OF
CWA LATER THIS EVENING. GENERALLY VFR MOSTLY CLEAR THIS PERIOD UNDER
HIGH PRESSURE...EXCEPT FOR IFR/LIFR RIVER AND VALLEY FOG 06Z TO 12Z
FRIDAY...AFFECTING ALL THE MAJOR TERMINALS.
AFTER 12Z FRIDAY...BECOMING VFR MOSTLY CLEAR AROUND 14Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING OF THE FOG MAY VARY BY AN HOUR OR TWO
LATER TONIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H M
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H M L L
PKB CONSISTENCY H H H H H H H H H H M L
CKB CONSISTENCY H H H H H H H H H H H M
AFTER 18Z FRIDAY...
BRIEF IFR POSSIBLE IN THUNDERSTORMS SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1243 PM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA LATER TODAY
INTO TONIGHT. A STRONGER COLD FRONT WILL CROSS THE REGION FRIDAY
NIGHT. HIGH PRESSURE OVER THE PLAINS SUNDAY WILL MOVE UP THE OHIO
VALLEY MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MADE MINOR CHANGES TO THE PREVIOUS FORECAST. LAKE BREEZE AND
WEAK DISSIPATING FRONTAL BOUNDARY WILL BE THE FOCUS FOR ISOLATED
TO SCATTERED THUNDERSTORMS. IF ANY STRONG UPDRAFTS CAN DEVELOP THE
POTENTIAL FOR A SEVERE WIND GUST EXISTS.
PREVIOUS DISCUSSION...
A WEAK COLD FRONT WILL SAG SOUTHWARD INTO THE REGION TODAY.
CONVERGENCE ALONG THE FRONT AND AFTERNOON HEATING SHOULD LEAD TO
SOME ISOLATED TO SCATTERED THUNDERSTORMS. IF ANY STRONG STORMS CAN
DEVELOP THERE WOULD BE A THREAT OF STRONGER WIND GUSTS.
OTHERWISE EXPECT TO SEE SOME AFTERNOON CUMULUS WITH SOME MIDDLE
LEVEL CONVECTIVE DEBRIS. HIGHS THIS AFTERNOON WILL BE IN THE MIDDLE
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
LINGERING THREAT FOR EVENING CONVECTION PER PREVIOUS DISCUSSION THEN
AIRMASS SETTLES DOWN DUE TO LOSS OF DAYTIME HEATING AND SLIGHTLY
DRIER AIR DRIFTING SE INTO THE AREA. SOME PATCHY FOG COULD DEVELOP.
DRY PERIOD WILL BE SHORT-LIVED. UPPER TROUGH DIGS SE INTO THE AREA
FOR SAT. A SURFACE WAVE OF LOW PRESSURE IS INDUCED ALONG A COLD
FRONT THAT WILL MOVE THROUGH FRI NIGHT. GOOD DYNAMICS SHOULD LEAD TO
WIDESPREAD SHRA/TSRA SPREADING EAST ACROSS THE CWA STARTING LATER
FRI INTO FRI NIGHT. SOME OF THE RAIN COULD BE LOCALLY HEAVY FRI
NIGHT INTO EARLY SAT. THE THREAT FOR THUNDER SHOULD SHIFT INTO JUST
THE EAST BY SAT MORNING.
COLDER AIR ALOFT WILL LEAD TO LAKE ENHANCEMENT FOR SHRA IN THE
SNOWBELT LATER SAT AND SAT NIGHT. A LITTLE THUNDER COULD OCCUR WITH
THE LAKE EFFECT CONVECTION.
HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON SUN AND THE UPPER
TROUGH AXIS BEGINS TO SHIFT EAST OF THE AREA DURING THE AFTERNOON.
THIS SHOULD KEEP THE SHRA THREAT LIMITED TO MOSTLY JUST THE EAST.
A LINGERING SHRA OR TWO COULD HANG AROUND OVER THE SNOWBELT SUN
NIGHT...OTHERWISE THE REST OF THE AREA SHOULD BE DRY AS DRIER AIR
AND SUBSIDENCE TAKE CONTROL.
NOTICEABLY COOLER TEMPS WILL ARRIVE FOR SAT AND CONTINUE SUN WITH
HIGHS MOSTLY IN THE 60S. LOWS BY SUN NIGHT SHOULD MAINLY BE IN A 50
TO 55 RANGE AS CLOUDS BEGIN TO BREAK UP.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
A MODERATING TREND IN TEMPERATURES FOR THE PERIOD. HIGH PRESSURE
WILL BE OVER THE AREA ON MONDAY AND THEN IT WILL MOVE EAST AND THE
SOUTHERLY FLOW WILL ALLOW TEMPERATURES TO WARM BACK TO NEAR NORMAL
LEVELS. DRY FOR THE PERIOD. EVEN THOUGH ON MONDAY THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 15C THE FLOW WILL BE SO WEAK
THAT JUST SOME CLOUDS WILL BE AROUND AND NO SHOWERS. A COLD FRONT
WILL BE MOVING THROUGH WEDNESDAY NIGHT BUT AT THIS TIME THAT MAY BE
DRY.
&&
.AVIATION /12Z THURSDAY THROUGH TUESDAY/...
AREAS OF FOG AND ISOLATED STRATUS WILL BURN OFF AFTER SUNRISE.
TODAYS WEATHER WILL BE CAUSED BY A COLD FRONT THAT WILL MOVE
THROUGH. AT 11Z THE COLD FRONT WAS LOCATED FROM WESTERN LOWER
MICHIGAN TO EAST OF CHICAGO TO NORTHERN MISSOURI. SOME CLOUDS WERE
ALONG IT. THE FRONT WILL MOVE THROUGH THE REGION MAINLY DURING THE
AFTERNOON. HOWEVER...SOME SHOWERS COULD DEVELOP OVER NORTHWEST
OHIO THIS MORNING. THE BEST CHANCE FOR THUNDER WILL BE FROM CLE
AND MFD SOUTHEAST. THE HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON
THINGS. THE BEST CHANCE TO HAVE THUNDER AT A TAF SITE WILL BE CAK
AND YNG. SINCE THE FRONT WILL BE THE CAUSE OF THE THUNDERSTORMS
THEY SHOULD BE IN A LINE WITH SOME ISOLATED CONVECTION AHEAD OF
IT.
CLOUDS WILL DECREASE TONIGHT. THE MODELS ARE VERY SLOW IN
DECREASING THE MOISTURE...THIS MAY BE TOO SLOW BASED ON WHAT IS
GOING ON NOW UPSTREAM. SOMETIMES AFTER A FRONTAL PASSAGE MVFR
CEILINGS DEVELOP. IN THIS CASE THE WIND SHIFT IS BRIEF. THE MODELS
DO HINT AT SOME MOISTURE NEAR ERIE...SO KEPT SOME SCATTERED
LOW CLOUDS IN THAT AREA. OTHERWISE THE AIRMASS IS TRYING TO DRY
OUT...SO NOT EXPECTING FOG AT THE TAF SITES...HOWEVER...PATCHY
MVFR FOG WILL OCCUR ELSEWHERE.
.OUTLOOK...NON VFR POSSIBLE FRIDAY NIGHT INTO SUNDAY.
&&
.MARINE...
A WEAK COLD FRONT WILL BE MOVING ACROSS THE LAKE TODAY. A SOUTHWEST
TO WEST FLOW AHEAD OF THE FRONT AND THEN A LIGHT NORTHWEST BEHIND
THE FRONT. NOT EXPECTING CONDITIONS TO MEET SMALL CRAFT ADVISORY
CONDITIONS. A FEW THUNDERSTORMS ON THE LAKE COULD BE STRONG LATER
TODAY. HIGH PRESSURE WILL MOVE ACROSS THE LAKE TONIGHT.
FRIDAY NIGHT THROUGH SUNDAY COULD BE INTERESTING ON THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE FRIDAY NIGHT WITH A NORTHWEST TO
NORTH FLOW FOR THE WHOLE WEEKEND. THE WINDS COULD BE STRONG ENOUGH
ESPECIALLY LATE FRIDAY NIGHT INTO SATURDAY TO PROMPT A SMALL CRAFT
ADVISORY ESPECIALLY ON THE EAST END OF THE LAKE. DETAILS ARE NOT
CLEAR AT THIS TIME. THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL
BE AROUND 15C FOR MOST OF SATURDAY AND SUNDAY AND WITH PLENTY OF
MOISTURE SOME COLD AIR WATERSPOUTS AND FUNNELS ARE QUITE POSSIBLE.
HIGH PRESSURE WILL MOVE ACROSS THE LAKE MONDAY AND THEN A SOUTHERLY
FLOW WILL DEVELOP FOR TUESDAY THROUGH WEDNESDAY. NOT EXPECTING SMALL
CRAFT ADVISORY CRITERIA DURING THIS PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...MULLEN
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1135 AM EDT THU SEP 6 2012
.SYNOPSIS...
WEAK COLD FRONT ARRIVES THIS EVENING. HIGH PRESSURE FRIDAY. STRONG
COLD FRONT SATURDAY. HIGH PRESSURE SUNDAY INTO THE NEXT WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE...NO SIGNIFICANT CHANGES.
600AM UPDATE...
NO SIGNIFICANT CHANGES MADE WITH THIS UPDATE...JUST TWEAKED
INITIAL SKY GRIDS.
PREVIOUS DISCUSSION BELOW...
SHRA CONT TO INCREASE ACROSS N CARTER AND S GREENUP AS OF
0630Z...WITH NEARLY STATIONARY MOTIONS. BUMPED UP POPS INTO LKLY
NEXT COUPLE HRS ACROSS NE KY COUNTIES. WILL BE MONITORING RAINFALL
AS WELL.
PREVIOUS DISCUSSION BELOW...
SHRA LIGHTING UP ON RADAR AT 06Z ACROSS W ZONES...ASSOCIATED WITH
S/W TROF AND EMBEDDED VORT MAX. RUC TRACKS THIS SLOWLY NE THRU CWA
BY 13Z. HAVE SOME LOW POPS WITH THIS AS IT DOES SO. BACK EDGE OF
CLDS WILL SLOWLY PUSH THRU PORTIONS OF SE OH BY 08Z...TAKING TO
NEAR SUNRISE TO GET INTO CENTRAL WV LOWLANDS. FURTHER COMPLICATING
SKY COVER IS LOW STRATUS THAT IS POISED TO DEVELOP ACROSS ALONG
AND E OF I79 CORRIDOR...BASED ON MODEL PROJECTIONS. THINK THIS MAY
END UP MORE IN MTNS AND S COAL FIELDS. SOME RVR VALLEY FG THROWN
IN AS WELL...ESPECIALLY FOR AREAS THAT MANAGE TO CLR.
WILL TRY TO SCT OUT ANY LOW CLDS BY MID MORNING. WILL LOOK FOR MTN
SHRA AND A FEW TSRA TO DEVELOP WITH HEATING AND WEAK OROGRAPHIC
LIFT. WILL CARRY CHC POPS THERE...TAILING OFF TO SCHC BACK TO I79
CORRIDOR. OTHERWISE...WEAK FRONT DROPPING SE THRU UPR OH VALLEY
LOOKS TO BE DELAYED UNTIL LATE AFTN FOR SE OH ZONES BEFORE BECOMING
RATHER DIFFUSE TONIGHT. HAVE ONLY SCHC POPS WITH THIS AS OVERALL
SETUP LOOKS RATHER MEAGER.
WILL ROLL A TICK OR TWO ABV WARMEST GUIDANCE FOR HIGHS TDY BASED
ON RECENT PERFORMANCE AND NEAR HIGH SIDE OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
MODELS HAVE COME INTO DECENT AGREEMENT THROUGHOUT THE PERIOD. MODELS
SHOW HIGH PRESSURE FOR FRIDAY. MESO NAM IS TRYING TO CREATE A FEW
SHOWERS IN THE MOUNTAINS...BUT BELIEVE THAT THE 700 MB AIR IS TOO
DRY. A FAST MOVING COLD FRONT THEN PUSHES THROUGH ON SATURDAY. WILL
FINE TUNE POPS FOR BETTER TIMING. HIGH PRESSURE THEN TAKES OVER
SATURDAY NIGHT INTO THE NEXT WORK WEEK. WILL REMOVE POPS SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
MADE WHOLESALE CHANGES TO THE LONG TERM FORECAST AS MODELS COMING
INTO BETTER AGREEMENT THAN YESTERDAY...NOW SHOWING OPEN WAVE
SWINGING THROUGH OVER THE WEEKEND...AND A THING OF THE PAST AS WE
HEAD INTO THE WORK WEEK. LINGER CHANCE AND SLIGHT CHANCE POPS
THROUGH SUNDAY...MOVING OUT SUNDAY NIGHT AS THE UPPER TROUGH MOVES
EAST AND OUT TO SEA. THIS WILL PROVIDE A MAINLY DRY FORECAST FOR THE
REST OF THE LONG TERM. DID NOT INCLUDE ANY POPS FOR THE WORK WEEK AT
THIS TIME DUE TO LACKING MOISTURE...BUT WITH NORTHWEST FLOW IT MAY
BE POSSIBLE TO GET A LITTLE SHORTWAVE RIPPLE THAT COULD POP A SHOWER
OR TWO AT SOME POINT. TEMPERATURES WILL START OFF BELOW NORMAL ON
MONDAY...WITH A GRADUAL WARMING TREND TO NEAR NORMAL BY MID TO LATE
WEEK AS UPPER RIDGE MOVES INTO SOUTHERN PLAINS.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
A WEAK DRY COLD FRONT WILL DROP SE INTO THE OH VALLEY THIS
AFTN...AND DISSIPATE AS IT COMES INTO NORTHERN PORTIONS OF CWA LATER
THIS EVENING. LINGERING MVFR CLOUDS SOUTH A HTS-CRW LINE WILL
SCATTER OUT TO A VFR CU FIELD BY 18Z...OTHERWISE VFR SCT CU.
IDEAL RADIATION COOLING NIGHT UNDER WEAK HIGH PRESSURE AND CLEAR
SKIES...WILL LEAD TO RIVER AND VALLEY IFR/LIFR FOG 06Z TO 12Z.
AFTER 12Z FRIDAY...BECOMING VFR MOSTLY CLEAR AROUND 14Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING AND DENSITY OF FOG AND/OR LOW STRATUS
MAY VARY TONIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M M M M H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z FRIDAY...
IFR FOG EXPECTED AT SOME TERMINALS 09 TO 12Z THURSDAY. BRIEF IFR
POSSIBLE IN THUNDERSTORMS SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
952 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA LATER TODAY
INTO TONIGHT. A STRONGER COLD FRONT WILL CROSS THE REGION FRIDAY
NIGHT. HIGH PRESSURE OVER THE PLAINS SUNDAY WILL MOVE UP THE OHIO
VALLEY MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK COLD FRONT WILL SAG SOUTHWARD INTO THE REGION TODAY.
CONVERGENCE ALONG THE FRONT AND AFTERNOON HEATING SHOULD LEAD TO
SOME ISOLATED TO SCATTERED THUNDERSTORMS. IF ANY STRONG STORMS CAN
DEVELOP THERE WOULD BE A THREAT OF STRONGER WIND GUSTS.
OTHERWISE EXPECT TO SEE SOME AFTERNOON CUMULUS WITH SOME MIDDLE
LEVEL CONVECTIVE DEBRIS. HIGHS THIS AFTERNOON WILL BE IN THE MIDDLE
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
LINGERING THREAT FOR EVENING CONVECTION PER PREVIOUS DISCUSSION THEN
AIRMASS SETTLES DOWN DUE TO LOSS OF DAYTIME HEATING AND SLIGHTLY
DRIER AIR DRIFTING SE INTO THE AREA. SOME PATCHY FOG COULD DEVELOP.
DRY PERIOD WILL BE SHORT-LIVED. UPPER TROUGH DIGS SE INTO THE AREA
FOR SAT. A SURFACE WAVE OF LOW PRESSURE IS INDUCED ALONG A COLD
FRONT THAT WILL MOVE THROUGH FRI NIGHT. GOOD DYNAMICS SHOULD LEAD TO
WIDESPREAD SHRA/TSRA SPREADING EAST ACROSS THE CWA STARTING LATER
FRI INTO FRI NIGHT. SOME OF THE RAIN COULD BE LOCALLY HEAVY FRI
NIGHT INTO EARLY SAT. THE THREAT FOR THUNDER SHOULD SHIFT INTO JUST
THE EAST BY SAT MORNING.
COLDER AIR ALOFT WILL LEAD TO LAKE ENHANCEMENT FOR SHRA IN THE
SNOWBELT LATER SAT AND SAT NIGHT. A LITTLE THUNDER COULD OCCUR WITH
THE LAKE EFFECT CONVECTION.
HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON SUN AND THE UPPER
TROUGH AXIS BEGINS TO SHIFT EAST OF THE AREA DURING THE AFTERNOON.
THIS SHOULD KEEP THE SHRA THREAT LIMITED TO MOSTLY JUST THE EAST.
A LINGERING SHRA OR TWO COULD HANG AROUND OVER THE SNOWBELT SUN
NIGHT...OTHERWISE THE REST OF THE AREA SHOULD BE DRY AS DRIER AIR
AND SUBSIDENCE TAKE CONTROL.
NOTICEABLY COOLER TEMPS WILL ARRIVE FOR SAT AND CONTINUE SUN WITH
HIGHS MOSTLY IN THE 60S. LOWS BY SUN NIGHT SHOULD MAINLY BE IN A 50
TO 55 RANGE AS CLOUDS BEGIN TO BREAK UP.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
A MODERATING TREND IN TEMPERATURES FOR THE PERIOD. HIGH PRESSURE
WILL BE OVER THE AREA ON MONDAY AND THEN IT WILL MOVE EAST AND THE
SOUTHERLY FLOW WILL ALLOW TEMPERATURES TO WARM BACK TO NEAR NORMAL
LEVELS. DRY FOR THE PERIOD. EVEN THOUGH ON MONDAY THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 15C THE FLOW WILL BE SO WEAK
THAT JUST SOME CLOUDS WILL BE AROUND AND NO SHOWERS. A COLD FRONT
WILL BE MOVING THROUGH WEDNESDAY NIGHT BUT AT THIS TIME THAT MAY BE
DRY.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AREAS OF FOG AND ISOLATED STRATUS WILL BURN OFF AFTER SUNRISE.
TODAYS WEATHER WILL BE CAUSED BY A COLD FRONT THAT WILL MOVE
THROUGH. AT 11Z THE COLD FRONT WAS LOCATED FROM WESTERN LOWER
MICHIGAN TO EAST OF CHICAGO TO NORTHERN MISSOURI. SOME CLOUDS WERE
ALONG IT. THE FRONT WILL MOVE THROUGH THE REGION MAINLY DURING THE
AFTERNOON. HOWEVER...SOME SHOWERS COULD DEVELOP OVER NORTHWEST
OHIO THIS MORNING. THE BEST CHANCE FOR THUNDER WILL BE FROM CLE
AND MFD SOUTHEAST. THE HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON
THINGS. THE BEST CHANCE TO HAVE THUNDER AT A TAF SITE WILL BE CAK
AND YNG. SINCE THE FRONT WILL BE THE CAUSE OF THE THUNDERSTORMS
THEY SHOULD BE IN A LINE WITH SOME ISOLATED CONVECTION AHEAD OF
IT.
CLOUDS WILL DECREASE TONIGHT. THE MODELS ARE VERY SLOW IN
DECREASING THE MOISTURE...THIS MAY BE TOO SLOW BASED ON WHAT IS
GOING ON NOW UPSTREAM. SOMETIMES AFTER A FRONTAL PASSAGE MVFR
CEILINGS DEVELOP. IN THIS CASE THE WIND SHIFT IS BRIEF. THE MODELS
DO HINT AT SOME MOISTURE NEAR ERIE...SO KEPT SOME SCATTERED
LOW CLOUDS IN THAT AREA. OTHERWISE THE AIRMASS IS TRYING TO DRY
OUT...SO NOT EXPECTING FOG AT THE TAF SITES...HOWEVER...PATCHY
MVFR FOG WILL OCCUR ELSEWHERE.
.OUTLOOK...NON VFR POSSIBLE FRIDAY NIGHT INTO SUNDAY.
&&
.MARINE...
A WEAK COLD FRONT WILL BE MOVING ACROSS THE LAKE TODAY. A SOUTHWEST
TO WEST FLOW AHEAD OF THE FRONT AND THEN A LIGHT NORTHWEST BEHIND
THE FRONT. NOT EXPECTING CONDITIONS TO MEET SMALL CRAFT ADVISORY
CONDITIONS. A FEW THUNDERSTORMS ON THE LAKE COULD BE STRONG LATER
TODAY. HIGH PRESSURE WILL MOVE ACROSS THE LAKE TONIGHT.
FRIDAY NIGHT THROUGH SUNDAY COULD BE INTERESTING ON THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE FRIDAY NIGHT WITH A NORTHWEST TO
NORTH FLOW FOR THE WHOLE WEEKEND. THE WINDS COULD BE STRONG ENOUGH
ESPECIALLY LATE FRIDAY NIGHT INTO SATURDAY TO PROMPT A SMALL CRAFT
ADVISORY ESPECIALLY ON THE EAST END OF THE LAKE. DETAILS ARE NOT
CLEAR AT THIS TIME. THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL
BE AROUND 15C FOR MOST OF SATURDAY AND SUNDAY AND WITH PLENTY OF
MOISTURE SOME COLD AIR WATERSPOUTS AND FUNNELS ARE QUITE POSSIBLE.
HIGH PRESSURE WILL MOVE ACROSS THE LAKE MONDAY AND THEN A SOUTHERLY
FLOW WILL DEVELOP FOR TUESDAY THROUGH WEDNESDAY. NOT EXPECTING SMALL
CRAFT ADVISORY CRITERIA DURING THIS PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...MULLEN
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
746 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL DRIFT SOUTHEAST ACROSS THE AREA LATER TODAY
INTO TONIGHT. A STRONGER COLD FRONT WILL CROSS THE REGION FRIDAY
NIGHT. HIGH PRESSURE OVER THE PLAINS SUNDAY WILL MOVE UP THE OHIO
VALLEY MONDAY AND TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLOUDS ASSOCIATED WITH DIFFUSE COLD FRONT STARTING TO MOVE INTO NW
CORNER OF THE CWA. PATCHY FOG SHOULD QUICKLY DISSIPATE THIS MORNING.
WEAK COLD FRONT SHOULD CROSS THE AREA LATER TODAY INTO EARLY
TONIGHT. GOOD INSTABILITY TO BE PRESENT LATER TODAY BUT WIND SHEAR
LACKING. THUS ONLY EXPECTING ISOLATED PULSE SEVERE STORMS. SHOULD
SEE AT LEAST A FEW TSRA DEVELOP WITH THE FRONT...ESPECIALLY OVER THE
EAST HALF TO 2/3 OF THE CWA. NOT SURE WHY NAM HAS NO QPF AT ALL
ANYWHERE IN THE CWA TODAY GIVEN THE SITUATION.
ANOTHER DAY OF ABOVE NORMAL TEMPS WHICH WILL BE MADE TO FEEL EVEN
WARMER DUE TO DEWPOINTS IN THE MID TO UPPER 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
LINGERING THREAT FOR EVENING CONVECTION PER PREVIOUS DISCUSSION THEN
AIRMASS SETTLES DOWN DUE TO LOSS OF DAYTIME HEATING AND SLIGHTLY
DRIER AIR DRIFTING SE INTO THE AREA. SOME PATCHY FOG COULD DEVELOP.
DRY PERIOD WILL BE SHORT-LIVED. UPPER TROUGH DIGS SE INTO THE AREA
FOR SAT. A SURFACE WAVE OF LOW PRESSURE IS INDUCED ALONG A COLD
FRONT THAT WILL MOVE THROUGH FRI NIGHT. GOOD DYNAMICS SHOULD LEAD TO
WIDESPREAD SHRA/TSRA SPREADING EAST ACROSS THE CWA STARTING LATER
FRI INTO FRI NIGHT. SOME OF THE RAIN COULD BE LOCALLY HEAVY FRI
NIGHT INTO EARLY SAT. THE THREAT FOR THUNDER SHOULD SHIFT INTO JUST
THE EAST BY SAT MORNING.
COLDER AIR ALOFT WILL LEAD TO LAKE ENHANCEMENT FOR SHRA IN THE
SNOWBELT LATER SAT AND SAT NIGHT. A LITTLE THUNDER COULD OCCUR WITH
THE LAKE EFFECT CONVECTION.
HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON SUN AND THE UPPER
TROUGH AXIS BEGINS TO SHIFT EAST OF THE AREA DURING THE AFTERNOON.
THIS SHOULD KEEP THE SHRA THREAT LIMITED TO MOSTLY JUST THE EAST.
A LINGERING SHRA OR TWO COULD HANG AROUND OVER THE SNOWBELT SUN
NIGHT...OTHERWISE THE REST OF THE AREA SHOULD BE DRY AS DRIER AIR
AND SUBSIDENCE TAKE CONTROL.
NOTICEABLY COOLER TEMPS WILL ARRIVE FOR SAT AND CONTINUE SUN WITH
HIGHS MOSTLY IN THE 60S. LOWS BY SUN NIGHT SHOULD MAINLY BE IN A 50
TO 55 RANGE AS CLOUDS BEGIN TO BREAK UP.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
A MODERATING TREND IN TEMPERATURES FOR THE PERIOD. HIGH PRESSURE
WILL BE OVER THE AREA ON MONDAY AND THEN IT WILL MOVE EAST AND THE
SOUTHERLY FLOW WILL ALLOW TEMPERATURES TO WARM BACK TO NEAR NORMAL
LEVELS. DRY FOR THE PERIOD. EVEN THOUGH ON MONDAY THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 15C THE FLOW WILL BE SO WEAK
THAT JUST SOME CLOUDS WILL BE AROUND AND NO SHOWERS. A COLD FRONT
WILL BE MOVING THROUGH WEDNESDAY NIGHT BUT AT THIS TIME THAT MAY BE
DRY.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AREAS OF FOG AND ISOLATED STRATUS WILL BURN OFF AFTER SUNRISE.
TODAYS WEATHER WILL BE CAUSED BY A COLD FRONT THAT WILL MOVE
THROUGH. AT 11Z THE COLD FRONT WAS LOCATED FROM WESTERN LOWER
MICHIGAN TO EAST OF CHICAGO TO NORTHERN MISSOURI. SOME CLOUDS WERE
ALONG IT. THE FRONT WILL MOVE THROUGH THE REGION MAINLY DURING THE
AFTERNOON. HOWEVER...SOME SHOWERS COULD DEVELOP OVER NORTHWEST
OHIO THIS MORNING. THE BEST CHANCE FOR THUNDER WILL BE FROM CLE
AND MFD SOUTHEAST. THE HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON
THINGS. THE BEST CHANCE TO HAVE THUNDER AT A TAF SITE WILL BE CAK
AND YNG. SINCE THE FRONT WILL BE THE CAUSE OF THE THUNDERSTORMS
THEY SHOULD BE IN A LINE WITH SOME ISOLATED CONVECTION AHEAD OF
IT.
CLOUDS WILL DECREASE TONIGHT. THE MODELS ARE VERY SLOW IN
DECREASING THE MOISTURE...THIS MAY BE TOO SLOW BASED ON WHAT IS
GOING ON NOW UPSTREAM. SOMETIMES AFTER A FRONTAL PASSAGE MVFR
CEILINGS DEVELOP. IN THIS CASE THE WIND SHIFT IS BRIEF. THE MODELS
DO HINT AT SOME MOISTURE NEAR ERIE...SO KEPT SOME SCATTERED
LOW CLOUDS IN THAT AREA. OTHERWISE THE AIRMASS IS TRYING TO DRY
OUT...SO NOT EXPECTING FOG AT THE TAF SITES...HOWEVER...PATCHY
MVFR FOG WILL OCCUR ELSEWHERE.
.OUTLOOK...NON VFR POSSIBLE FRIDAY NIGHT INTO SUNDAY.
&&
.MARINE...
A WEAK COLD FRONT WILL BE MOVING ACROSS THE LAKE TODAY. A SOUTHWEST
TO WEST FLOW AHEAD OF THE FRONT AND THEN A LIGHT NORTHWEST BEHIND
THE FRONT. NOT EXPECTING CONDITIONS TO MEET SMALL CRAFT ADVISORY
CONDITIONS. A FEW THUNDERSTORMS ON THE LAKE COULD BE STRONG LATER
TODAY. HIGH PRESSURE WILL MOVE ACROSS THE LAKE TONIGHT.
FRIDAY NIGHT THROUGH SUNDAY COULD BE INTERESTING ON THE LAKE. A COLD
FRONT WILL MOVE ACROSS THE LAKE FRIDAY NIGHT WITH A NORTHWEST TO
NORTH FLOW FOR THE WHOLE WEEKEND. THE WINDS COULD BE STRONG ENOUGH
ESPECIALLY LATE FRIDAY NIGHT INTO SATURDAY TO PROMPT A SMALL CRAFT
ADVISORY ESPECIALLY ON THE EAST END OF THE LAKE. DETAILS ARE NOT
CLEAR AT THIS TIME. THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL
BE AROUND 15C FOR MOST OF SATURDAY AND SUNDAY AND WITH PLENTY OF
MOISTURE SOME COLD AIR WATERSPOUTS AND FUNNELS ARE QUITE POSSIBLE.
HIGH PRESSURE WILL MOVE ACROSS THE LAKE MONDAY AND THEN A SOUTHERLY
FLOW WILL DEVELOP FOR TUESDAY THROUGH WEDNESDAY. NOT EXPECTING SMALL
CRAFT ADVISORY CRITERIA DURING THIS PERIOD.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...ADAMS
SHORT TERM...ADAMS
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
609 AM EDT THU SEP 6 2012
.SYNOPSIS...
WEAK COLD FRONT ARRIVES THIS EVENING. HIGH PRESSURE FRIDAY. STRONG
COLD FRONT SATURDAY. HIGH PRESSURE SUNDAY INTO THE NEXT WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
600AM UPDATE...
NO SIGNIFICANT CHANGES MADE WITH THIS UPDATE...JUST TWEAKED
INITIAL SKY GRIDS.
PREVIOUS DISCUSSION BELOW...
SHRA CONT TO INCREASE ACROSS N CARTER AND S GREENUP AS OF
0630Z...WITH NEARLY STATIONARY MOTIONS. BUMPED UP POPS INTO LKLY
NEXT COUPLE HRS ACROSS NE KY COUNTIES. WILL BE MONITORING RAINFALL
AS WELL.
PREVIOUS DISCUSSION BELOW...
SHRA LIGHTING UP ON RADAR AT 06Z ACROSS W ZONES...ASSOCIATED WITH
S/W TROF AND EMBEDDED VORT MAX. RUC TRACKS THIS SLOWLY NE THRU CWA
BY 13Z. HAVE SOME LOW POPS WITH THIS AS IT DOES SO. BACK EDGE OF
CLDS WILL SLOWLY PUSH THRU PORTIONS OF SE OH BY 08Z...TAKING TO
NEAR SUNRISE TO GET INTO CENTRAL WV LOWLANDS. FURTHER COMPLICATING
SKY COVER IS LOW STRATUS THAT IS POISED TO DEVELOP ACROSS ALONG
AND E OF I79 CORRIDOR...BASED ON MODEL PROJECTIONS. THINK THIS MAY
END UP MORE IN MTNS AND S COAL FIELDS. SOME RVR VALLEY FG THROWN
IN AS WELL...ESPECIALLY FOR AREAS THAT MANAGE TO CLR.
WILL TRY TO SCT OUT ANY LOW CLDS BY MID MORNING. WILL LOOK FOR MTN
SHRA AND A FEW TSRA TO DEVELOP WITH HEATING AND WEAK OROGRAPHIC
LIFT. WILL CARRY CHC POPS THERE...TAILING OFF TO SCHC BACK TO I79
CORRIDOR. OTHERWISE...WEAK FRONT DROPPING SE THRU UPR OH VALLEY
LOOKS TO BE DELAYED UNTIL LATE AFTN FOR SE OH ZONES BEFORE BECOMING
RATHER DIFFUSE TONIGHT. HAVE ONLY SCHC POPS WITH THIS AS OVERALL
SETUP LOOKS RATHER MEAGER.
WILL ROLL A TICK OR TWO ABV WARMEST GUIDANCE FOR HIGHS TDY BASED
ON RECENT PERFORMANCE AND NEAR HIGH SIDE OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
MODELS HAVE COME INTO DECENT AGREEMENT THROUGHOUT THE PERIOD. MODELS
SHOW HIGH PRESSURE FOR FRIDAY. MESO NAM IS TRYING TO CREATE A FEW
SHOWERS IN THE MOUNTAINS...BUT BELIEVE THAT THE 700 MB AIR IS TOO
DRY. A FAST MOVING COLD FRONT THEN PUSHES THROUGH ON SATURDAY. WILL
FINE TUNE POPS FOR BETTER TIMING. HIGH PRESSURE THEN TAKES OVER
SATURDAY NIGHT INTO THE NEXT WORK WEEK. WILL REMOVE POPS SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
MADE WHOLESALE CHANGES TO THE LONG TERM FORECAST AS MODELS COMING
INTO BETTER AGREEMENT THAN YESTERDAY...NOW SHOWING OPEN WAVE
SWINGING THROUGH OVER THE WEEKEND...AND A THING OF THE PAST AS WE
HEAD INTO THE WORK WEEK. LINGER CHANCE AND SLIGHT CHANCE POPS
THROUGH SUNDAY...MOVING OUT SUNDAY NIGHT AS THE UPPER TROUGH MOVES
EAST AND OUT TO SEA. THIS WILL PROVIDE A MAINLY DRY FORECAST FOR THE
REST OF THE LONG TERM. DID NOT INCLUDE ANY POPS FOR THE WORK WEEK AT
THIS TIME DUE TO LACKING MOISTURE...BUT WITH NORTHWEST FLOW IT MAY
BE POSSIBLE TO GET A LITTLE SHORTWAVE RIPPLE THAT COULD POP A SHOWER
OR TWO AT SOME POINT. TEMPERATURES WILL START OFF BELOW NORMAL ON
MONDAY...WITH A GRADUAL WARMING TREND TO NEAR NORMAL BY MID TO LATE
WEEK AS UPPER RIDGE MOVES INTO SOUTHERN PLAINS.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
FG AND STRATUS WILL MIX OUT 13 TO 14Z FOR A RETURN TO VFR
CONDITIONS. AFTN HEATING WILL ALLOW FOR LOW END CU DEVELOPMENT
WITH SOME MTN CONVECTION POSSIBLE. LEFT OUT OF MTN TAFS AT THIS
DISTANCE THOUGH DUE TO LACK OF EXPECTED COVERAGE. A WEAK COLD
FRONT WILL DROP SE INTO UPR OH VALLEY THIS AFTN...TAKING UNTIL
LATE TO CROSS INTO SE OH. SOME SHRA OR TSRA POSSIBLE WITH THIS BUT
CHCS TOO LOW FOR INCLUDING IN NEAREST TAF SITE...KPKB...BEFORE
BOUNDARY BECOMES RATHER DIFFUSE IN NATURE TONIGHT E OF OH RVR.
HAVE IFR/LIFR FG FOR TONIGHT WITH A MAINLY CLR SKY EXPECTED.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: TIMING AND DENSITY OF FOG AND/OR LOW STRATUS
MAY VARY TONIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY L L L H H H H H H H H H
HTS CONSISTENCY M M M H H H H H H H H H
BKW CONSISTENCY L L L H M M M H H H H H
EKN CONSISTENCY L L H M H H H H H H H H
PKB CONSISTENCY L H H H H H H H H H H H
CKB CONSISTENCY M H H H H H H H H H H H
AFTER 12Z FRIDAY...
IFR FOG EXPECTED AT SOME TERMINALS 09 TO 12Z THURSDAY. BRIEF IFR
POSSIBLE IN THUNDERSTORMS SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
337 AM EDT THU SEP 6 2012
.SYNOPSIS...
WEAK COLD FRONT ARRIVES THIS EVENING. HIGH PRESSURE FRIDAY. STRONG
COLD FRONT SATURDAY. HIGH PRESSURE SUNDAY INTO THE NEXT WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
SHRA CONT TO INCREASE ACROSS N CARTER AND S GREENUP AS OF
0630Z...WITH NEARLY STATIONARY MOTIONS. BUMPED UP POPS INTO LKLY
NEXT COUPLE HRS ACROSS NE KY COUNTIES. WILL BE MONITORING RAINFALL
AS WELL.
PREVIOUS DISCUSSION BELOW...
SHRA LIGHTING UP ON RADAR AT 06Z ACROSS W ZONES...ASSOCIATED WITH
S/W TROF AND EMBEDDED VORT MAX. RUC TRACKS THIS SLOWLY NE THRU CWA
BY 13Z. HAVE SOME LOW POPS WITH THIS AS IT DOES SO. BACK EDGE OF
CLDS WILL SLOWLY PUSH THRU PORTIONS OF SE OH BY 08Z...TAKING TO
NEAR SUNRISE TO GET INTO CENTRAL WV LOWLANDS. FURTHER COMPLICATING
SKY COVER IS LOW STRATUS THAT IS POISED TO DEVELOP ACROSS ALONG
AND E OF I79 CORRIDOR...BASED ON MODEL PROJECTIONS. THINK THIS MAY
END UP MORE IN MTNS AND S COAL FIELDS. SOME RVR VALLEY FG THROWN
IN AS WELL...ESPECIALLY FOR AREAS THAT MANAGE TO CLR.
WILL TRY TO SCT OUT ANY LOW CLDS BY MID MORNING. WILL LOOK FOR MTN
SHRA AND A FEW TSRA TO DEVELOP WITH HEATING AND WEAK OROGRAPHIC
LIFT. WILL CARRY CHC POPS THERE...TAILING OFF TO SCHC BACK TO I79
CORRIDOR. OTHERWISE...WEAK FRONT DROPPING SE THRU UPR OH VALLEY
LOOKS TO BE DELAYED UNTIL LATE AFTN FOR SE OH ZONES BEFORE BECOMING
RATHER DIFFUSE TONIGHT. HAVE ONLY SCHC POPS WITH THIS AS OVERALL
SETUP LOOKS RATHER MEAGER.
WILL ROLL A TICK OR TWO ABV WARMEST GUIDANCE FOR HIGHS TDY BASED
ON RECENT PERFORMANCE AND NEAR HIGH SIDE OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
MODELS HAVE COME INTO DECENT AGREEMENT THROUGHOUT THE PERIOD. MODELS
SHOW HIGH PRESSURE FOR FRIDAY. MESO NAM IS TRYING TO CREATE A FEW
SHOWERS IN THE MOUNTAINS...BUT BELIEVE THAT THE 700 MB AIR IS TOO
DRY. A FAST MOVING COLD FRONT THEN PUSHES THROUGH ON SATURDAY. WILL
FINE TUNE POPS FOR BETTER TIMING. HIGH PRESSURE THEN TAKES OVER
SATURDAY NIGHT INTO THE NEXT WORK WEEK. WILL REMOVE POPS SATURDAY
NIGHT THROUGH SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
MADE WHOLESALE CHANGES TO THE LONG TERM FORECAST AS MODELS COMING
INTO BETTER AGREEMENT THAN YESTERDAY...NOW SHOWING OPEN WAVE
SWINGING THROUGH OVER THE WEEKEND...AND A THING OF THE PAST AS WE
HEAD INTO THE WORK WEEK. LINGER CHANCE AND SLIGHT CHANCE POPS
THROUGH SUNDAY...MOVING OUT SUNDAY NIGHT AS THE UPPER TROUGH MOVES
EAST AND OUT TO SEA. THIS WILL PROVIDE A MAINLY DRY FORECAST FOR THE
REST OF THE LONG TERM. DID NOT INCLUDE ANY POPS FOR THE WORK WEEK AT
THIS TIME DUE TO LACKING MOISTURE...BUT WITH NORTHWEST FLOW IT MAY
BE POSSIBLE TO GET A LITTLE SHORTWAVE RIPPLE THAT COULD POP A SHOWER
OR TWO AT SOME POINT. TEMPERATURES WILL START OFF BELOW NORMAL ON
MONDAY...WITH A GRADUAL WARMING TREND TO NEAR NORMAL BY MID TO LATE
WEEK AS UPPER RIDGE MOVES INTO SOUTHERN PLAINS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
YET ANOTHER TRICKY AVIATION FCST THRU THIS MORNING. AN ABUNDANCE
OF MID/HI CLDS WILL BE SLOW TO PUSH E...TAKING UNTIL SUNRISE OR SO
TO EXIT N MTNS COURTESY OF S/W TROF AND EMBEDDED VORT MAX. IN FACT
SOME SHRA NOTED WITH THIS FEATURE AND HAVE SHRA MENTION IN TAFS
NEXT FEW HRS FOR KEKN WITH VCSH AT KHTS.
FURTHER COMPLICATING MATTERS IS ABUNDANCE OF LLVL MOISTURE
REMAINING WHICH MAY LEAD TO LOW STRATUS FORMATION AFTER 09Z. THIS
LOOKS TO BE MOST LKLY ACROSS S COAL FIELDS AND IN THE MTNS WHERE
KBKW WAS CODED UP WITH IFR CIGS THRU 13Z. THINK KEKN MAY FG DOWN
INSTEAD AND HAVE LIFR CONDITIONS AS A RESULT. ELSEWHERE...HARD TO
PIN DOWN FG DEVELOPMENT GIVING MID/HI CLDS CURRENTLY OVER AREA.
WILL ALLOW KPKB AND KCRW TO GO INTO IFR/LIFR 10 TO 12Z WITH MVFR
VSBY FOR KHTS AND KCKB.
ANY FG AND STRATUS WILL MIX OUT 13 TO 14Z FOR A RETURN TO VFR
CONDITIONS. AFTN HEATING WILL ALLOW FOR LOW END CU DEVELOPMENT
WITH SOME MTN CONVECTION POSSIBLE. LEFT OUT OF MTN TAFS AT THIS
DISTANCE THOUGH DUE TO LACK OF EXPECTED COVERAGE. A WEAK COLD FRONT
WILL DROP SE INTO UPR OH VALLEY THIS AFTN...TAKING UNTIL LATE TO
CROSS INTO SE OH. SOME SHRA OR TSRA POSSIBLE WITH THIS BUT CHCS
TOO LOW FOR INCLUDING IN NEAREST TAF SITE...KPKB...BEFORE BOUNDARY
BECOMES RATHER DIFFUSE IN NATURE TONIGHT E OF OH RVR.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND DENSITY OF FOG AND/OR LOW STRATUS
MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 09/06/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M L L L L L L H H H H H
HTS CONSISTENCY M L L L L L L H H H H H
BKW CONSISTENCY H M M M H H H H H H H H
EKN CONSISTENCY M L L L L L L L H H H H
PKB CONSISTENCY M L L L L L L H H H H H
CKB CONSISTENCY M M L L L L L H H H H H
AFTER 06Z FRIDAY...
IFR FOG EXPECTED AT SOME TERMINALS 09 TO 12Z THURSDAY. BRIEF IFR
POSSIBLE IN THUNDERSTORMS SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
229 AM EDT THU SEP 6 2012
.SYNOPSIS...
WEAK COLD FRONT ARRIVES THIS EVENING FOLLOWED BY AN UPPER LEVEL
LOW AND SURFACE COLD FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
SHRA CONT TO INCREASE ACROSS N CARTER AND S GREENUP AS OF
0630Z...WITH NEARLY STATIONARY MOTIONS. BUMPED UP POPS INTO LKLY
NEXT COUPLE HRS ACROSS NE KY COUNTIES. WILL BE MONITORING RAINFALL
AS WELL.
PREVIOUS DISCUSSION BELOW...
SHRA LIGHTING UP ON RADAR AT 06Z ACROSS W ZONES...ASSOCIATED WITH
S/W TROF AND EMBEDDED VORT MAX. RUC TRACKS THIS SLOWLY NE THRU CWA
BY 13Z. HAVE SOME LOW POPS WITH THIS AS IT DOES SO. BACK EDGE OF
CLDS WILL SLOWLY PUSH THRU PORTIONS OF SE OH BY 08Z...TAKING TO
NEAR SUNRISE TO GET INTO CENTRAL WV LOWLANDS. FURTHER COMPLICATING
SKY COVER IS LOW STRATUS THAT IS POISED TO DEVELOP ACROSS ALONG
AND E OF I79 CORRIDOR...BASED ON MDL PROJECTIONS. THINK THIS MAY
END UP MORE IN MTNS AND S COAL FIELDS. SOME RVR VALLEY FG THROWN
IN AS WELL...ESPECIALLY FOR AREAS THAT MANAGE TO CLR.
WILL TRY TO SCT OUT ANY LOW CLDS BY MID MORNING. WILL LOOK FOR MTN
SHRA AND A FEW TSRA TO DEVELOP WITH HEATING AND WEAK OROGRAPHIC
LIFT. WILL CARRY CHC POPS THERE...TAILING OFF TO SCHC BACK TO I79
CORRIDOR. OTHERWISE...WEAK FRONT DROPPING SE THRU UPR OH VALLEY
LOOKS TO BE DELAYED UNTIL LATE AFTN FOR SE OH ZONES BEFORE BECOMING
RATHER DIFFUSE TONIGHT. HAVE ONLY SCHC POPS WITH THIS AS OVERALL
SETUP LOOKS RATHER MEAGER.
WILL ROLL A TICK OR TWO ABV WARMEST GUIDANCE FOR HIGHS TDY BASED
ON RECENT PERFORMANCE AND NEAR HIGH SIDE OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
PRECIP WILL COME TO AN END FROM WEST TO EAST THURSDAY NIGHT AS WEAK
FRONT PULLS AWAY/DISSIPATES. NAM LINGERS MOISTURE INTO
FRIDAY...WHILE GFS IS A BIT FASTER MOVING IT OUT. HAVE SLIGHT CHANCE
POPS IN THE MOUNTAINS FRIDAY AFTERNOON TO ACCOUNT FOR ANY ISOLATED
DIURNAL CONVECTION THAT MAY DEVELOP.
ONLY A SHORT BREAK BEFORE THE NEXT SYSTEM MOVES IN FOR THE WEEKEND.
MODELS AND ENSEMBLES HAVE CONTINUED TRENDING TOWARDS THE IDEA OF AN
OPEN TROUGH...AND KEEP IT FAIRLY PROGRESSIVE. WITH THIS IN
MIND...SPED UP ENTIRE SYSTEM A BIT...WITH SLIGHT CHANCE POPS
ENTERING SE OHIO LATE FRIDAY EVENING AND INTO THE WV MOUNTAINS
OVERNIGHT. THEN HAVE LIKELY POPS INTO SE OHIO BY SATURDAY MORNING
AND THE WV MOUNTAINS EARLY SATURDAY AFTERNOON. KEPT THE HIGHEST POPS
ALONG AND IN FRONT OF THE SURFACE COLD FRONT...WHICH SHOULD CROSS
THE OHIO RIVER 18Z-20Z AND EXIT EAST OF FORECAST AREA SATURDAY
NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MADE WHOLESALE CHANGES TO THE LONG TERM FORECAST AS MODELS COMING
INTO BETTER AGREEMENT THAN YESTERDAY...NOW SHOWING OPEN WAVE
SWINGING THROUGH OVER THE WEEKEND...AND A THING OF THE PAST AS WE
HEAD INTO THE WORK WEEK. LINGER CHANCE AND SLIGHT CHANCE POPS
THROUGH SUNDAY...MOVING OUT SUNDAY NIGHT AS THE UPPER TROUGH MOVES
EAST AND OUT TO SEA. THIS WILL PROVIDE A MAINLY DRY FORECAST FOR THE
REST OF THE LONG TERM. DID NOT INCLUDE ANY POPS FOR THE WORK WEEK AT
THIS TIME DUE TO LACKING MOISTURE...BUT WITH NORTHWEST FLOW IT MAY
BE POSSIBLE TO GET A LITTLE SHORTWAVE RIPPLE THAT COULD POP A SHOWER
OR TWO AT SOME POINT. TEMPERATURES WILL START OFF BELOW NORMAL ON
MONDAY...WITH A GRADUAL WARMING TREND TO NEAR NORMAL BY MID TO LATE
WEEK AS UPPER RIDGE MOVES INTO SOUTHERN PLAINS.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
YET ANOTHER TRICKY AVIATION FCST THRU THIS MORNING. AN ABUNDANCE
OF MID/HI CLDS WILL BE SLOW TO PUSH E...TAKING UNTIL SUNRISE OR SO
TO EXIT N MTNS COURTESY OF S/W TROF AND EMBEDDED VORT MAX. IN FACT
SOME SHRA NOTED WITH THIS FEATURE AND HAVE SHRA MENTION IN TAFS
NEXT FEW HRS FOR KEKN WITH VCSH AT KHTS.
FURTHER COMPLICATING MATTERS IS ABUNDANCE OF LLVL MOISTURE
REMAINING WHICH MAY LEAD TO LOW STRATUS FORMATION AFTER 09Z. THIS
LOOKS TO BE MOST LKLY ACROSS S COAL FIELDS AND IN THE MTNS WHERE
KBKW WAS CODED UP WITH IFR CIGS THRU 13Z. THINK KEKN MAY FG DOWN
INSTEAD AND HAVE LIFR CONDITIONS AS A RESULT. ELSEWHERE...HARD TO
PIN DOWN FG DEVELOPMENT GIVING MID/HI CLDS CURRENTLY OVER AREA.
WILL ALLOW KPKB AND KCRW TO GO INTO IFR/LIFR 10 TO 12Z WITH MVFR
VSBY FOR KHTS AND KCKB.
ANY FG AND STRATUS WILL MIX OUT 13 TO 14Z FOR A RETURN TO VFR
CONDITIONS. AFTN HEATING WILL ALLOW FOR LOW END CU DEVELOPMENT
WITH SOME MTN CONVECTION POSSIBLE. LEFT OUT OF MTN TAFS AT THIS
DISTANCE THOUGH DUE TO LACK OF EXPECTED COVERAGE. A WEAK COLD FRONT
WILL DROP SE INTO UPR OH VALLEY THIS AFTN...TAKING UNTIL LATE TO
CROSS INTO SE OH. SOME SHRA OR TSRA POSSIBLE WITH THIS BUT CHCS
TOO LOW FOR INCLUDING IN NEAREST TAF SITE...KPKB...BEFORE BOUNDARY
BECOMES RATHER DIFFUSE IN NATURE TONIGHT E OF OH RVR.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND DENSITY OF FOG AND/OR LOW STRATUS
MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 09/06/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M L L L L L L H H H H H
HTS CONSISTENCY M L L L L L L H H H H H
BKW CONSISTENCY H M M M H H H H H H H H
EKN CONSISTENCY M L L L L L L L H H H H
PKB CONSISTENCY M L L L L L L H H H H H
CKB CONSISTENCY M M L L L L L H H H H H
AFTER 06Z FRIDAY...
IFR FOG EXPECTED AT SOME TERMINALS 09 TO 12Z THURSDAY. BRIEF IFR
POSSIBLE IN THUNDERSTORMS SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
209 AM EDT THU SEP 6 2012
.SYNOPSIS...
WEAK COLD FRONT ARRIVES THIS EVENING FOLLOWED BY AN UPPER LEVEL
LOW AND SURFACE COLD FRONT FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHRA LIGHTING UP ON RADAR AT 06Z ACROSS W ZONES...ASSOCIATED WITH S/W
TROF AND EMBEDDED VORT MAX. RUC TRACKS THIS SLOWLY NE THRU CWA BY
13Z. HAVE SOME LOW POPS WITH THIS AS IT DOES SO. BACK EDGE OF CLDS
WILL SLOWLY PUSH THRU PORTIONS OF SE OH BY 08Z...TAKING TO NEAR
SUNRISE TO GET INTO CENTRAL WV LOWLANDS. FURTHER COMPLICATING SKY
COVER IS LOW STRATUS THAT IS POISED TO DEVELOP ACROSS ALONG AND E
OF I79 CORRIDOR...BASED ON MDL PROJECTIONS. THINK THIS MAY END UP
MORE IN MTNS AND S COAL FIELDS. SOME RVR VALLEY FG THROWN IN AS
WELL...ESPECIALLY FOR AREAS THAT MANAGE TO CLR.
WILL TRY TO SCT OUT ANY LOW CLDS BY MID MORNING. WILL LOOK FOR MTN
SHRA AND A FEW TSRA TO DEVELOP WITH HEATING AND WEAK OROGRAPHIC
LIFT. WILL CARRY CHC POPS THERE...TAILING OFF TO SCHC BACK TO I79
CORRIDOR. OTHERWISE...WEAK FRONT DROPPING SE THRU UPR OH VALLEY
LOOKS TO BE DELAYED UNTIL LATE AFTN FOR SE OH ZONES BEFORE BECOMING
RATHER DIFFUSE TONIGHT. HAVE ONLY SCHC POPS WITH THIS AS OVERALL
SETUP LOOKS RATHER MEAGER.
WILL ROLL A TICK OR TWO ABV WARMEST GUIDANCE FOR HIGHS TDY BASED
ON RECENT PERFORMANCE AND NEAR HIGH SIDE OF GUIDANCE FOR LOWS
TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
PRECIP WILL COME TO AN END FROM WEST TO EAST THURSDAY NIGHT AS WEAK
FRONT PULLS AWAY/DISSIPATES. NAM LINGERS MOISTURE INTO
FRIDAY...WHILE GFS IS A BIT FASTER MOVING IT OUT. HAVE SLIGHT CHANCE
POPS IN THE MOUNTAINS FRIDAY AFTERNOON TO ACCOUNT FOR ANY ISOLATED
DIURNAL CONVECTION THAT MAY DEVELOP.
ONLY A SHORT BREAK BEFORE THE NEXT SYSTEM MOVES IN FOR THE WEEKEND.
MODELS AND ENSEMBLES HAVE CONTINUED TRENDING TOWARDS THE IDEA OF AN
OPEN TROUGH...AND KEEP IT FAIRLY PROGRESSIVE. WITH THIS IN
MIND...SPED UP ENTIRE SYSTEM A BIT...WITH SLIGHT CHANCE POPS
ENTERING SE OHIO LATE FRIDAY EVENING AND INTO THE WV MOUNTAINS
OVERNIGHT. THEN HAVE LIKELY POPS INTO SE OHIO BY SATURDAY MORNING
AND THE WV MOUNTAINS EARLY SATURDAY AFTERNOON. KEPT THE HIGHEST POPS
ALONG AND IN FRONT OF THE SURFACE COLD FRONT...WHICH SHOULD CROSS
THE OHIO RIVER 18Z-20Z AND EXIT EAST OF FORECAST AREA SATURDAY
NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MADE WHOLESALE CHANGES TO THE LONG TERM FORECAST AS MODELS COMING
INTO BETTER AGREEMENT THAN YESTERDAY...NOW SHOWING OPEN WAVE
SWINGING THROUGH OVER THE WEEKEND...AND A THING OF THE PAST AS WE
HEAD INTO THE WORK WEEK. LINGER CHANCE AND SLIGHT CHANCE POPS
THROUGH SUNDAY...MOVING OUT SUNDAY NIGHT AS THE UPPER TROUGH MOVES
EAST AND OUT TO SEA. THIS WILL PROVIDE A MAINLY DRY FORECAST FOR THE
REST OF THE LONG TERM. DID NOT INCLUDE ANY POPS FOR THE WORK WEEK AT
THIS TIME DUE TO LACKING MOISTURE...BUT WITH NORTHWEST FLOW IT MAY
BE POSSIBLE TO GET A LITTLE SHORTWAVE RIPPLE THAT COULD POP A SHOWER
OR TWO AT SOME POINT. TEMPERATURES WILL START OFF BELOW NORMAL ON
MONDAY...WITH A GRADUAL WARMING TREND TO NEAR NORMAL BY MID TO LATE
WEEK AS UPPER RIDGE MOVES INTO SOUTHERN PLAINS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
YET ANOTHER TRICKY AVIATION FCST THRU THIS MORNING. AN ABUNDANCE
OF MID/HI CLDS WILL BE SLOW TO PUSH E...TAKING UNTIL SUNRISE OR SO
TO EXIT N MTNS COURTESY OF S/W TROF AND EMBEDDED VORT MAX. IN FACT
SOME SHRA NOTED WITH THIS FEATURE AND HAVE SHRA MENTION IN TAFS
NEXT FEW HRS FOR KEKN WITH VCSH AT KHTS.
FURTHER COMPLICATING MATTERS IS ABUNDANCE OF LLVL MOISTURE
REMAINING WHICH MAY LEAD TO LOW STRATUS FORMATION AFTER 09Z. THIS
LOOKS TO BE MOST LKLY ACROSS S COAL FIELDS AND IN THE MTNS WHERE
KBKW WAS CODED UP WITH IFR CIGS THRU 13Z. THINK KEKN MAY FG DOWN
INSTEAD AND HAVE LIFR CONDITIONS AS A RESULT. ELSEWHERE...HARD TO
PIN DOWN FG DEVELOPMENT GIVING MID/HI CLDS CURRENTLY OVER AREA.
WILL ALLOW KPKB AND KCRW TO GO INTO IFR/LIFR 10 TO 12Z WITH MVFR
VSBY FOR KHTS AND KCKB.
ANY FG AND STRATUS WILL MIX OUT 13 TO 14Z FOR A RETURN TO VFR
CONDITIONS. AFTN HEATING WILL ALLOW FOR LOW END CU DEVELOPMENT
WITH SOME MTN CONVECTION POSSIBLE. LEFT OUT OF MTN TAFS AT THIS
DISTANCE THOUGH DUE TO LACK OF EXPECTED COVERAGE. A WEAK COLD FRONT
WILL DROP SE INTO UPR OH VALLEY THIS AFTN...TAKING UNTIL LATE TO
CROSS INTO SE OH. SOME SHRA OR TSRA POSSIBLE WITH THIS BUT CHCS
TOO LOW FOR INCLUDING IN NEAREST TAF SITE...KPKB...BEFORE BOUNDARY
BECOMES RATHER DIFFUSE IN NATURE TONIGHT E OF OH RVR.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND DENSITY OF FOG AND/OR LOW STRATUS
MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE THU 09/06/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M L L L L L L H H H H H
HTS CONSISTENCY M L L L L L L H H H H H
BKW CONSISTENCY H M M M H H H H H H H H
EKN CONSISTENCY M L L L L L L L H H H H
PKB CONSISTENCY M L L L L L L H H H H H
CKB CONSISTENCY M M L L L L L H H H H H
AFTER 06Z FRIDAY...
IFR FOG EXPECTED AT SOME TERMINALS 09 TO 12Z THURSDAY. BRIEF IFR
POSSIBLE IN THUNDERSTORMS SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...30
AREA FORECAST DISCUSSION
NWS TULSA OK
640 PM CDT FRI SEP 7 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SHOWERS AND THUNDERSTORMS CONTINUE TO ROLL THROUGH THE AREA. HAVE
TRIED TO TIME THE MOVEMENTS AND USED IN TIMING THE WEATHER. HIGH
PRESSURE WILL BUILD OVER THE AREA FROM THE NORTHWEST AND BRING A
RAPID END TO THE PRECIPITATION FROM THE NORTHWEST TO SOUTHEAST.
ALSO EXPECT SKIES TO CLEAR FROM THE NORTHWEST STARTING AROUND
MIDNIGHT. LOW...MVFR...CIGS EXPECTED OVER NORTHWEST ARKANSAS
DURING THE EVENING...THEN CLOUDS SHIFT EAST. VFR CLR ON SATURDAY.
/SA
&&
.PREV DISCUSSION... /ISSUED 320 PM CDT FRI SEP 7 2012/
DISCUSSION...
CHANGES ARE A COMING. THE SURFACE COLD FRONT...WHICH WAS HELD UP
FOR A TIME TODAY AS A WEAK LOW PRESSURE RIPPLED ON BY...IS NOW ON
THE MOVE. WIND GUSTS ARE TOPPING 50 MPH BEHIND THE FRONT...DUE TO
THE TIGHT PRESSURE GRADIENT AND ISALLOBARIC FORCING. AS THIS
FRONT MOVES SOUTH THE POTENTIAL FOR STRONG WIND GUSTS IN EXCESS OF
40 MPH WILL LIKELY CONTINUE...MAINLY ACROSS NORTHEAST OK. WILL LET
THE ONGOING WIND ADVISORY CONTINUE THRU 03Z AND LET THE EVENING
SHIFT ADJUST IF NEED BE. AHEAD OF THE FRONT...TEMPS HAVE SOARED
ONCE THE MID CLOUDS CLEARED OUT ENOUGH TO ALLOW FOR SOME
INSOLATION. BRISTOW MESONET HAS HIT 108 DEGREES. MUCH OF EASTERN
OK IN FACT IS ABOVE 100 DEGREES THIS HOUR. WILL LET THE HEAT
HEADLINES CONTINUE THROUGH 00Z...AND WE WILL FINALLY BE ABLE TO
SHELVE THIS FOR AWHILE BY TONIGHT.
PRECIP CHANCES WILL BE A CHALLENGE...ESPECIALLY FOR WESTERN
SECTIONS. THE HRRR SUGGESTS THAT CONVECTION WILL GRADUALLY
INCREASE IN COVERAGE IN THE VICINITY OF THE FRONT THIS
AFTERNOON...EVENTUALLY ORGANIZING INTO LINE SEGMENTS OR CLUSTERS
AS THEY MOVE INTO FAR EASTERN OK AND WESTERN AR THIS EVENING. THE
LATEST ECMWF ALSO SUGGESTS A BAND OF POST FRONTAL CONVECTION WILL
DEVELOP LATER ON TONIGHT...AS STRONG MID LVL COLD FRONTOGENESIS
AND QG FORCING FOR ASCENT INCREASES AS THE MAIN SHORTWAVE
APPROACHES. I HAVE ADJUSTED POPS UPWARD ACROSS NORTHEAST OK IN
ANTICIPATION OF THIS. GIVEN THE INSTABILITY AND GRADUALLY
INCREASING SHEAR WITH TIME...SEVERE WIND AND HAIL ARE A GOOD
POSSIBILITY...ESPECIALLY IF AN ORGANIZED LINE SEGMENT OR CLUSTER
CAN GET GOING IN THE HOT WARM SECTOR. PRECIP CHANCES WILL QUICKLY
SHIFT SOUTHEAST AFTER 06Z AND SHOULD BE DONE BY 12Z WITH SKIES
CLEARING OUT.
SHOULD BE A VERY NICE WEEKEND WITH HIGHS IN THE 80S AND LOWS IN
THE 50S...EVEN UPPER 40S BY SUNDAY MORNING OVER PARTS OF NW AR. A
BACK DOOR FRONT WILL ATTEMPT TO KEEP THE WARMING TREND IN CHECK
OVER NE OK AND NW AR SUNDAY AFTERNOON. TEMPS WILL WARM BACK INTO
THE 90S EARLY NEXT WEEK WITH SHORTWAVE RIDGING OVERHEAD. A FRONTAL
BOUNDARY WILL EVENTUALLY PUSH INTO THE REGION BY FRIDAY OF NEXT
WEEK...AND THERE IS REASONABLE ENOUGH AGREEMENT BETWEEN THE MEDIUM
RANGE MODELS TO INSERT A SLIGHT CHANCE FOR THE TAIL END OF THE
FORECAST.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 101 55 80 53 / 50 60 0 0
FSM 104 61 81 54 / 80 60 0 0
MLC 106 60 81 54 / 50 40 0 0
BVO 98 54 81 51 / 60 50 0 0
FYV 97 55 76 48 / 80 80 0 0
BYV 96 54 75 49 / 80 80 0 0
MKO 105 57 80 53 / 50 60 0 0
MIO 93 55 78 53 / 60 70 0 0
F10 104 58 80 56 / 50 50 0 0
HHW 103 63 82 55 / 10 30 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...RED FLAG WARNING UNTIL 8 PM FRIDAY FOR OKZ061-OKZ062-OKZ067-
OKZ068-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075.
HEAT ADVISORY UNTIL 7 PM FRIDAY FOR OKZ049-OKZ060-OKZ064-OKZ065-
OKZ066-OKZ067-OKZ068-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-
OKZ075-OKZ076.
WIND ADVISORY UNTIL 10 PM FRIDAY FOR OKZ054-OKZ055-OKZ056-OKZ057-
OKZ058-OKZ059-OKZ060-OKZ061-OKZ062-OKZ063-OKZ064-OKZ065-
OKZ066-OKZ067.
EXCESSIVE HEAT WARNING UNTIL 7 PM FRIDAY FOR OKZ053.
AR...HEAT ADVISORY UNTIL 7 PM FRIDAY FOR ARZ019-ARZ020.
EXCESSIVE HEAT WARNING UNTIL 7 PM FRIDAY FOR ARZ029.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...02
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
448 PM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SLOWLY ACROSS THE STATE TODAY AND
TONIGHT. AN UPPER TROUGH WILL FORM OVER THE GREAT LAKES AND
MIDWEST AND AMPLIFY AS IT APPROACHES PENNSYLVANIA...BRINGING
UNSETTLED WEATHER INTO THE WEEKEND. HIGH PRESSURE WILL BUILD INTO
THE AREA LATE MONDAY...BRINGING IN COOLER TEMPERATURES...BEFORE
MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MINOR UPDATE TO EDGE POPS UP ACROSS THE NORTH. STORMS HAVE
FORMED AHEAD OF COLD FRONT AND ON ALLEGANY FRONT.
EARLIER DISCUSSION BELOW.
A WEAK COLD FRONT ENTERING WESTERN PA WILL BE THE FOCUS FOR
SOME SCATTERED CONVECTION THIS AFTERNOON. BEHIND THE DEPARTING
SHORTWAVE CURRENTLY BRINGING SOME CLOUDS TO SERN ZONES...SATELLITE
AND RUC DATA SUPPORT A MSUNNY DAY ACROSS THE NWRN 2/3 OR SO OF THE
FCST AREA...WITH INCREASING SUNSHINE FOR THE AFTERNOON ACROSS THE
SE PART OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
RUC INDICATES STEEPENING MID LEVEL LAPSE RATES ALREADY DEVELOPING
OVER WESTERN PA IN RESPONSE TO STRONG HEATING AND SLOWLY FALLING
MID LEVEL TAMPS AND HEIGHTS. SPC RAP SHOWS CAPES EXCEEDING 3000J
OVER WRN PA. MOISTURE CONVERGENCE IS WEAK HOWEVER AND VIZ SHOTS
ARE JUST STARTING TO SHOW THE DEVELOPMENT OF A CU FIELD BACK OVER
THE LOWER LAKES. THIS SHOULD CONTINUE TO DEVELOP AS THE DAY HEATS
UP...WITH THE BEST CHANCES FOR STORMS BEING OVER MY NWRN
COUNTIES.
THE INSTABILITY COMBINED WITH SOME MODEST WIND SHEAR COULD BE
ENOUGH TO SUPPORT ISOLATED STRONG WIND GUSTS IN SOME OF THE
THUNDERSTORMS.
ACTIVITY SHOULD WANE AFTER THE LOSS OF HEATING...LEADING TO A
MAINLY DRY OVERNIGHT WITH MORE OF THE KIND OF LATE NIGHT FOG AND
LOW CLOUDS WE HAVE SEEN OVER THE LAST FEW NIGHTS. IT WILL REMAIN
QUITE MILD...IN THE 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A WEAK HIGH WILL BUILD INTO THE AREA BY LATE FRIDAY AS THE
FRONTAL BOUNDARY LIFTS BACK NORTH AS A WARM FRONT INTO NEW YORK
STATE. SW FLOW AT THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND
SOMEWHAT HUMID CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP
OUT IN THE U80S TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO
AROUND 70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GFS AND THE NEW NAM KEEP US DRY THRU THE DAY FRIDAY. THIS LOOKS
MORE REASONABLE THAN THE SMALL CHC POPS OF THE 09Z SREF.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA WELL AFTER MIDNIGHT ACROSS THE
ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. BASED ON THIS...LEFT CHC POPS IN...MORE IN
LINE WITH THE GFS...THAN THE NAM MODEL.
ON THE COOL SIDE FOR SAT ACROSS THE FAR WEST...AND THE AREA
SUNDAY INTO TUE AM...BUT NOTHING ABNORMAL FOR LATE AUG...
EARLY SEPT. TUE AM COULD BE AS COOL ACROSS THE SE...AS OTHER
AREAS.
MINOR ADJUSTMENTS TO TEMPS. TOOK OUT SHOWERS FOR SUNDAY
NIGHT.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
A SW FLOW FOR THU...BUT STILL DRY...AS THE HIGH MOVES EAST.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
STILL SHOWING MDT/LNS HANGING DOGGEDLY ONTO CIGS AROUND 3000```BUT
I EXPECT THESE TO LIFT QUICKLY SO HAVE STARTED THE NEW TAF PACKAGE
OFF AS VFR AT ALL SITES.
THE REST OF THE AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING
THE THREAT WITH LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS
WELL AS THE POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS. MOST LIKLEY AREAS TO SEE THIS SHOULD BE ALONG
NY...PA BORDER.
EXPECT MORE LATE NIGHT FOG AND LOW CLOUDS TONIGHT.
OUTLOOK...
FRI...MAINLY VFR AFTER EARLY MORNING FOG/LOW CLOUD RESTRICTIONS.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE AND COLD FRONT.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
MON-TUE...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE/MARTIN
SHORT TERM...LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
344 PM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SLOWLY ACROSS THE STATE TODAY AND
TONIGHT. AN UPPER TROUGH WILL FORM OVER THE GREAT LAKES AND
MIDWEST AND AMPLIFY AS IT APPROACHES PENNSYLVANIA...BRINGING
UNSETTLED WEATHER INTO THE WEEKEND. HIGH PRESSURE WILL BUILD INTO
THE AREA LATE MONDAY...BRINGING IN COOLER TEMPERATURES...BEFORE
MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A WEAK COLD FRONT ENTERING WESTERN PA WILL BE THE FOCUS FOR SOME
SCATTERED CONVECTION THIS AFTERNOON. BEHIND THE DEPARTING
SHORTWAVE CURRENTLY BRINGING SOME CLOUDS TO SERN ZONES...SATELLITE
AND RUC DATA SUPPORT A MSUNNY DAY ACROSS THE NWRN 2/3 OR SO OF
THE FCST AREA...WITH INCREASING SUNSHINE FOR THE AFTERNOON ACROSS
THE SE PART OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
RUC INDICATES STEEPENING MID LEVEL LAPSE RATES ALREADY DEVELOPING
OVER WESTERN PA IN RESPONSE TO STRONG HEATING AND SLOWLY FALLING
MID LEVEL TAMPS AND HEIGHTS. SPC RAP SHOWS CAPES EXCEEDING 3000J
OVER WRN PA. MOISTURE CONVERGENCE IS WEAK HOWEVER AND VIZ SHOTS
ARE JUST STARTING TO SHOW THE DEVELOPMENT OF A CU FIELD BACK OVER
THE LOWER LAKES. THIS SHOULD CONTINUE TO DEVELOP AS THE DAY HEATS
UP...WITH THE BEST CHANCES FOR STORMS BEING OVER MY NWRN
COUNTIES.
THE INSTABILITY COMBINED WITH SOME MODEST WIND SHEAR COULD BE
ENOUGH TO SUPPORT ISOLATED STRONG WIND GUSTS IN SOME OF THE
THUNDERSTORMS.
ACTIVITY SHOULD WANE AFTER THE LOSS OF HEATING...LEADING TO A
MAINLY DRY OVERNIGHT WITH MORE OF THE KIND OF LATE NIGHT FOG AND
LOW CLOUDS WE HAVE SEEN OVER THE LAST FEW NIGHTS. IT WILL REMAIN
QUITE MILD...IN THE 60S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
A WEAK HIGH WILL BUILD INTO THE AREA BY LATE FRIDAY AS THE
FRONTAL BOUNDARY LIFTS BACK NORTH AS A WARM FRONT INTO NEW YORK
STATE. SW FLOW AT THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND
SOMEWHAT HUMID CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP
OUT IN THE U80S TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO
AROUND 70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GFS AND THE NEW NAM KEEP US DRY THRU THE DAY FRIDAY. THIS LOOKS
MORE REASONABLE THAN THE SMALL CHC POPS OF THE 09Z SREF.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA WELL AFTER MIDNIGHT ACROSS THE
ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. BASED ON THIS...LEFT CHC POPS IN...MORE IN
LINE WITH THE GFS...THAN THE NAM MODEL.
ON THE COOL SIDE FOR SAT ACROSS THE FAR WEST...AND THE AREA
SUNDAY INTO TUE AM...BUT NOTHING ABNORMAL FOR LATE AUG...
EARLY SEPT. TUE AM COULD BE AS COOL ACROSS THE SE...AS OTHER
AREAS.
MINOR ADJUSTMENTS TO TEMPS. TOOK OUT SHOWERS FOR SUNDAY
NIGHT.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
A SW FLOW FOR THU...BUT STILL DRY...AS THE HIGH MOVES EAST.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
STILL SHOWING MDT/LNS HANGING DOGGEDLY ONTO CIGS AROUND 3000```BUT
I EXPECT THESE TO LIFT QUICKLY SO HAVE STARTED THE NEW TAF PACKAGE
OFF AS VFR AT ALL SITES.
THE REST OF THE AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING
THE THREAT WITH LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS
WELL AS THE POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS. MOST LIKLEY AREAS TO SEE THIS SHOULD BE ALONG
NY...PA BORDER.
EXPECT MORE LATE NIGHT FOG AND LOW CLOUDS TONIGHT.
OUTLOOK...
FRI...MAINLY VFR AFTER EARLY MORNING FOG/LOW CLOUD RESTRICTIONS.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE AND COLD FRONT.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
MON-TUE...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
145 PM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SLOWLY ACROSS THE STATE TODAY AND
TONIGHT. AN UPPER TROUGH WILL FORM OVER THE GREAT LAKES AND
MIDWEST AND AMPLIFY AS IT APPROACHES PENNSYLVANIA...BRINGING
UNSETTLED WEATHER INTO THE WEEKEND. HIGH PRESSURE WILL BUILD INTO
THE AREA LATE MONDAY...BRINGING IN COOLER TEMPERATURES...BEFORE
MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WEAK COLD FRONT ENTERING WESTERN PA WILL BE THE FOCUS FOR SOME
SCATTERED CONVECTION THIS AFTERNOON. BEHIND THE DEPARTING
SHORTWAVE CURRENTLY BRINGING SOME CLOUDS TO SERN ZONES...SATELLITE
AND RUC DATA SUPPORT A MSUNNY DAY ACROSS THE NWRN 2/3 OR SO OF
THE FCST AREA...WITH INCREASING SUNSHINE FOR THE AFTERNOON ACROSS
THE SE PART OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
RUC INDICATES STEEPENING MID LEVEL LAPSE RATES ALREADY DEVELOPING
OVER WESTERN PA IN RESPONSE TO STRONG HEATING AND SLOWLY FALLING
MID LEVEL TAMPS AND HEIGHTS. SPC RAP SHOWS CAPES EXCEEDING 3000J
OVER WRN PA. MOISTURE CONVERGENCE IS WEAK HOWEVER AND VIZ SHOTS
ARE JUST STARTING TO SHOW THE DEVELOPMENT OF A CU FIELD BACK OVER
THE LOWER LAKES. THIS SHOULD CONTINUE TO DEVELOP AS THE DAY HEATS
UP...WITH THE BEST CHANCES FOR STORMS BEING OVER MY NWRN
COUNTIES.
THE INSTABILITY COMBINED WITH SOME MODEST WIND SHEAR COULD BE
ENOUGH TO SUPPORT ISOLATED STRONG WIND GUSTS IN SOME OF THE
THUNDERSTORMS.
ACTIVITY SHOULD WANE AFTER THE LOSS OF HEATING...LEADING TO A
MAINLY DRY OVERNIGHT WITH MORE OF THE KIND OF LATE NIGHT FOG AND
LOW CLOUDS WE HAVE SEEN OVER THE LAST FEW NIGHTS. IT WILL REMAIN
QUITE MILD...IN THE 60S.
&&
.SHORT TERM /FRIDAY/...
A WEAK HIGH WILL BUILD INTO THE AREA BY LATE FRIDAY AS THE
FRONTAL BOUNDARY LIFTS BACK NORTH AS A WARM FRONT INTO NEW YORK
STATE. SW FLOW AT THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND
SOMEWHAT HUMID CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP
OUT IN THE U80S TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO
AROUND 70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GFS AND THE NEW NAM KEEP US DRY THRU THE DAY FRIDAY. THIS LOOKS
MORE REASONABLE THAN THE SMALL CHC POPS OF THE 09Z SREF.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA BECOMING LIKELY WELL AFTER MIDNIGHT
ACROSS THE ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. DID LOWER TEMPS A TAD FOR SOME PERIODS AFTER
SATURDAY.
WITH THE UPPER LVL LOW MOVING OUT FASTER NOW...SHOULD BE DRY ON
MONDAY.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
STILL SHOWING MDT/LNS HANGING DOGGEDLY ONTO CIGS AROUND 3000```BUT
I EXPECT THESE TO LIFT QUICKLY SO HAVE STARTED THE NEW TAF PACKAGE
OFF AS VFR AT ALL SITES.
THE REST OF THE AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING
THE THREAT WITH LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS
WELL AS THE POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS. MOST LIKLEY AREAS TO SEE THIS SHOULD BE ALONG
NY...PA BORDER.
EXPECT MORE LATE NIGHT FOG AND LOW CLOUDS TONIGHT.
OUTLOOK...
FRI...MAINLY VFR AFTER EARLY MORNING FOG/LOW CLOUD RESTRICTIONS.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE AND COLD FRONT.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
MON-TUE...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1050 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SLOWLY ACROSS THE REGION TODAY AND
TONIGHT. AN UPPER TROUGH WILL FORM OVER THE GREAT LAKES AND
MIDWEST DURING THE WEEKEND THEN AMPLIFY AS IT APPROACHES
PENNSYLVANIA...BRINGING UNSETTLED WEATHER INTO THE WEEKEND. HIGH
PRESSURE WILL BUILD INTO THE AREA LATE MONDAY...BRINGING IN COOLER
TEMPERATURES...BEFORE MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A WEAK COLD FRONT ENTERING WESTERN PA WILL PROVIDE THE FOCUS FOR
SOME SCATTERED CONVECTION LATER TODAY. IN THE MEANTIME A WEAK
UPPER TROF IS BRINGING A FEW SPRINKLES TO MY FAR SERN ZONES AND
WILL CONTINUE OFF TO THE EAST BY EARLY AFTERNOON. BEHIND THIS
FEATURE...LATEST SATELLITE AND RUC DATA SUPPORTS A MSUNNY DAY
ACROSS THE NWRN 2/3 OR SO OF THE FCST AREA...WITH INCREASING
SUNSHINE FOR THE AFTERNOON ACROSS THE SE PART OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
RUC INDICATES STEEPENING MID LEVEL LAPSE RATES ALREADY DEVELOPING
OVER WESTERN PA IN RESPONSE TO STRONG HEATING AND SLOWLY FALLING
MID LEVEL TAMPS AND HEIGHTS. SPC RAP SHOWS CAPES EXCEEDING 200J
OVER WRN PA. MOISTURE CONVERGENCE IS WEAK HOWEVER AND VIZ SHOTS
ARE JUST STARTING TO SHOW THE DEVELOPMENT OF A CU FIELD. BACK OVER
THE LOWER LAKES. THIS SHOULD CONTINUE TO DEVELOP AS THE DAY HEATS
UP...WITH THE BEST CHANCES FOR RAIN BEING OVER MY NWRN COUNTIES.
THE INSTABILITY COMBINED WITH SOME MODEST WIND SHEAR COULD BE
ENOUGH TO SUPPORT ISOLATED STRONG WIND GUSTS IN SOME OF THE
THUNDERSTORMS.
&&
.SHORT TERM /FRIDAY/...
A WEAK HIGH WILL BUILD INTO THE AREA BY LATE FRIDAY AS THE
FRONTAL BOUNDARY LIFTS NORTH AS A WARM FRONT INTO NEW YORK STATE.
SW FLOW AT THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND SOMEWHAT
HUMID CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP OUT IN
THE U80S TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO AROUND
70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GFS AND THE NEW NAM KEEP US DRY THRU THE DAY FRIDAY. THIS LOOKS
MORE REASONABLE THAN THE SMALL CHC POPS OF THE 09Z SREF.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA BECOMING LIKELY WELL AFTER MIDNIGHT
ACROSS THE ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. DID LOWER TEMPS A TAD FOR SOME PERIODS AFTER
SATURDAY.
WITH THE UPPER LVL LOW MOVING OUT FASTER NOW...SHOULD BE DRY ON
MONDAY.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
STILL SOME LINGERING CIGS JUST UNDER 3000` OVER SERN PA...BUT ALL
SITES WILL IMPROVE TO VFR BY 18Z.
THE AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING THE THREAT
WITH LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS WELL AS THE
POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS. MOST LIKLEY AREAS TO SEE THIS SHOULD BE ALONG
NY...PA BORDER.
EXPECT MORE LATE NIGHT FOG AND LOW CLOUDS TONIGHT.
OUTLOOK...
FRI...MAINLY VFR AFTER EARLY MORNING FOG/LOW CLOUD RESTRICTIONS.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
MON...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
801 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE OVER THE REGION THIS MORNING WILL SLIDE
EAST TO THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON. A COLD FRONT
WILL MOVE INTO THE AREA TONIGHT AND FRIDAY. AN UPPER TROUGH WILL
FORM OVER THE GREAT LAKES AND MIDWEST DURING THE WEEKEND THEN
AMPLIFY AS IT APPROACHES PENNSYLVANIA...CREATING AN UNSETTLED AND
WET WEATHER PATTERN INTO THE WEEKEND. HIGH PRESSURE WILL BUILD INTO
THE AREA LATE MONDAY...BRINGING IN COOLER TEMPERATURES...BEFORE
MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK RIDGE OF HIGH PRESSURE /1012MB/ RESIDES OVER THE REGION EARLY
THIS MORNING. MODERATELY STG...MID/UPPER WARM ADVECTION WAS
RESPONSIBLE CREATING AN EXTENSIVE /AND THICK/ SHIELD OF ALTO CU AND
CIRROSTRATUS OVER THE STATE.
THE WESTERN EDGE OF THIS MID AND HIGH CLOUD SHIELD /NEAR THE
OHIO/PENN BORDER AT 09Z/ WILL CONTINUE TO SLIDE TO THE EAST AT
APPROX 20KT...AND REACH A LINE FROM KELM...TO KUNV AND KAOO BY
15-16Z TDY...AND 17-19Z ACROSS THE WEST BRANCH AND MID SUSQ VALLEY.
MIN TEMPS AROUND SUNRISE WILL HAVE QUITE A TIGHT RANGE OF ONLY ABOUT
6-7 DEG F /U50S TO MID 60S/ FROM THE NORMALLY COLDER NW MTNS...TO
THE LOWER SUSQ VALLEY.
THE UPPER SHORTWAVE WITH IT/S PRECEDING WARM ADVECTION ALOFT AND
ITS BKN MID AND HIGH CLOUD DECK WILL BE PASSING EAST OF THE AREA
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. BEHIND THIS
FEATURE...06Z RUC SUPPORTS A MSUNNY MORNING ACROSS THE WESTERN
MTNS...WITH INCREASING/LESS FILTERED SUNSHINE FOR THE AFTERNOON
ACROSS THE SE HALF OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
AFTER AN APPROX 7-8 HOUR PERIOD OF TRANQUIL CONDITIONS FOR THE FIRST
HALF OF THE DAYLIGHT HOURS...CU WILL INCREASE AND GROW VERTICALLY
DURING THE AFTN...AS A POCKET OF STEEP MID LEVEL LAPSE RATES /AROUND
7C PER KM/ OVERSPREADS THE CWA AHEAD OF NEXT SHORTWAVE AND ASSOC
COLD FRONT.
00Z-03Z MDLS/SREF GENERATE A RESPECTABLE AMOUNT OF CAPE BY LATE IN
THE AFTERNOON TODAY. THE BEST CHC OF TSRA WILL BE ACROSS THE NCENT
AND NW MTNS...WHERE LARGE SCALE FORCING AND DECENT UPPER LEVEL
DIVERGENCE...WILL COMBINE WITH MDTLY STG LLVL THETA-E CONVERGENCE
AND MID-LEVEL WESTERLY WINDS.
SFC DEW POINTS MAINLY IN THE LOWER TO MID 60S...WILL HELP TO CREATE
MLCAPES AROUND 1500 J/KG THIS AFTERNOON INTO EARLY THIS EVENING.
THIS INSTABILITY COMBINED WITH THE MODERATE WIND SHEAR COULD BE
ENOUGH TO SUPPORT ISOLD SVR MULTI-CELL TSTORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
WEAK LLVL RIDGING MOVES IN FROM THE WEST AS THE BEST UPPER LEVEL
DIVERGENCE WANES/SHIFTS TWD THE MID ATLANTIC COAST. SCATTERED
SHRA/TSRA WILL OCCUR MAINLY BEFORE MIDNIGHT...BUT ISOLATED SHRA/TSRA
WILL STILL BE POSSIBLE LATE AS THE LLVL FRONTAL BOUNDARY STALLS OUT
TEMPORARILY FROM ABOUT KAVP TO KUNV AND KPIT...AND MU/ML CAPES
REMAIN QUITE HIGH GIVEN THE LINGERING POCKET OF STEEP LAPSE RATES
ALOFT AND MOIST BLYR WITH DEWPOINTS IN THE LOWER TO MID 60S ACROSS
THE CENTRAL ZONES...AND PERHAPS AROUND A MUGGY 70F IN THE
SOUTHEAST.
WEAK HIGH BUILDS INTO THE AREA BY LATE FRIDAY AS THE FRONTAL
BOUNDARY LIFTS NORTH AS A WARM FRONT INTO NEW YORK STATE. SW FLOW AT
THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND SOMEWHAT HUMID
CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP OUT IN THE U80S
TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO AROUND 70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GRIDDED SKY COVER /CU TOPPED BY PERIODS OF CIRRUS/ WILL AVERAGE
AROUND 50 PERCENT THROUGH THE DAY FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA BECOMING LIKELY WELL AFTER MIDNIGHT
ACROSS THE ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. DID LOWER TEMPS A TAD FOR SOME PERIODS AFTER
SATURDAY.
WITH THE UPPER LVL LOW MOVING OUT FASTER NOW...SHOULD BE DRY ON
MONDAY.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
LOW STRATOCU FORMED ONLY IPT AND WILL LIFT BY MID MORNING. THIS
AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING THE THREAT WITH
LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS WELL AS THE
POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS. AREAS TO RECEIVE THIS SHOULD BE ALONG NY...PA
BORDER. EXPECT ANOTHER ROUND OF FOG/STRATOCU POSSIBLE TONIGHT.
OUTLOOK...
THU...MAINLY VFR AFTER MORNING FOG. SCT SHOWERS/THUNDERSTORMS
DEVELOPING BY AFTERNOON AND LASTING INTO EVENING.
FRI...MAINLY VFR.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
753 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE OVER THE REGION THIS MORNING WILL SLIDE
EAST TO THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON. A COLD FRONT
WILL MOVE INTO THE AREA TONIGHT AND FRIDAY. AN UPPER TROUGH WILL
FORM OVER THE GREAT LAKES AND MIDWEST DURING THE WEEKEND THEN
AMPLIFY AS IT APPROACHES PENNSYLVANIA...CREATING AN UNSETTLED AND
WET WEATHER PATTERN FOR THE WEEKEND. HIGH PRESSURE WILL BUILD INTO
THE AREA LATE MONDAY...BRINGING IN COOLER TEMPERATURES...BEFORE
MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK COLD FRONT ENTERING WESTERN PA EARLY TODAY WILL PROVIDE THE
FOCUS FOR SOME SCATTERED CONVECTION LATER TODAY. IN THE MEANTIME A
WEAK UPPER TROF IS BRINGING A FEW SPRINKLES TO MY SERN ZONES AND
WILL CONTINUE OFF TO THE EAST BY MID TO LATE MORNING. BEHIND THIS
FEATURE...THE RUC SUPPORTS A MSUNNY MORNING ACROSS THE WESTERN
MTNS...WITH INCREASING SUNSHINE FOR LATER IN THE MORNING AND
AFTERNOON ACROSS THE SE HALF OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
AFTER AN APPROX 7-8 HOUR PERIOD OF TRANQUIL CONDITIONS FOR THE FIRST
HALF OF THE DAY...CU WILL INCREASE AND GROW AS A POCKET OF
STEEPENING LAPSE RATES...AS MUCH AS 7C/KM...OVERSPREADS THE CWA
AHEAD OF NEXT SHORTWAVE.
SFC DEW POINTS MAINLY IN THE LOWER TO MID 60S...WILL HELP TO
CREATE MLCAPES AROUND 1500 J/KG THIS AFTERNOON INTO EARLY THIS
EVENING. THIS INSTABILITY COMBINED WITH THE MODERATE WIND SHEAR
COULD BE ENOUGH TO SUPPORT ISOLD SVR MULTI-CELL TSTORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
WEAK LLVL RIDGING MOVES IN FROM THE WEST AS THE BEST UPPER LEVEL
DIVERGENCE WANES/SHIFTS TWD THE MID ATLANTIC COAST. SCATTERED
SHRA/TSRA WILL OCCUR MAINLY BEFORE MIDNIGHT...BUT ISOLATED SHRA/TSRA
WILL STILL BE POSSIBLE LATE AS THE LLVL FRONTAL BOUNDARY STALLS OUT
TEMPORARILY FROM ABOUT KAVP TO KUNV AND KPIT...AND MU/ML CAPES
REMAIN QUITE HIGH GIVEN THE LINGERING POCKET OF STEEP LAPSE RATES
ALOFT AND MOIST BLYR WITH DEWPOINTS IN THE LOWER TO MID 60S ACROSS
THE CENTRAL ZONES...AND PERHAPS AROUND A MUGGY 70F IN THE
SOUTHEAST.
WEAK HIGH BUILDS INTO THE AREA BY LATE FRIDAY AS THE FRONTAL
BOUNDARY LIFTS NORTH AS A WARM FRONT INTO NEW YORK STATE. SW FLOW AT
THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND SOMEWHAT HUMID
CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP OUT IN THE U80S
TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO AROUND 70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GRIDDED SKY COVER /CU TOPPED BY PERIODS OF CIRRUS/ WILL AVERAGE
AROUND 50 PERCENT THROUGH THE DAY FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA BECOMING LIKELY WELL AFTER MIDNIGHT
ACROSS THE ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. DID LOWER TEMPS A TAD FOR SOME PERIODS AFTER
SATURDAY.
WITH THE UPPER LVL LOW MOVING OUT FASTER NOW...SHOULD BE DRY ON
MONDAY.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
CURRENT SATELLITE HAS WIDESPREAD MIDDLE TO HIGH CLOUDS MOVING OVER
THE STATE. THIS WILL REDUCE THE PROBABILITIES FOR FOG OVERNIGHT AND
THIS MORNING. CURRENT DEW POINT DEPRESSIONS ARE IN THE SINGLE
DIGITS...WHICH IS A GOOD SIDE FOR FOG. WITH THE CALM WINDS ACROSS
THE BOARD AND AN INVERSION IN PLACE...PATCHY FOG IS CERTAINLY
PROBABLY THROUGH ANY MID TO HIGH CLOUDS WILL REDUCE ITS INTENSITY.
SO EXPECT TO SEE THE DEVELOPMENT OF SOME VALLEY FOG BY 2-4 AM AND
CONTINUE A FEW HOURS AFTER SUNRISE. VIZ WILL BE THE PRIMARY
RESTRICTIONS UNTIL CONDITIONS LIFT...IN THE 1-3 MILE
RANGE...THOUGH UNV COULD SEE IFR OR LOWER CIGS. CONDITIONS WILL
CONTINUE UNTIL MID TO LATE MORNING.
THURS AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING THE THREAT
WITH LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS WELL AS THE
POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS.
OUTLOOK...
THU...MAINLY VFR AFTER MORNING FOG. SCT SHOWERS/THUNDERSTORMS
DEVELOPING BY AFTERNOON AND LASTING INTO EVENING.
FRI...MAINLY VFR.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
515 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE OVER THE REGION THIS MORNING WILL SLIDE
EAST TO THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON. A COLD FRONT
WILL MOVE INTO THE AREA TONIGHT AND FRIDAY. AN UPPER TROUGH WILL
FORM OVER THE GREAT LAKES AND MIDWEST DURING THE WEEKEND THEN
AMPLIFY AS IT APPROACHES PENNSYLVANIA...CREATING AN UNSETTLED AND
WET WEATHER PATTERN INTO THE WEEKEND. HIGH PRESSURE WILL BUILD INTO
THE AREA LATE MONDAY...BRINGING IN COOLER TEMPERATURES...BEFORE
MOVING OFF THE COAST LATER IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A WEAK RIDGE OF HIGH PRESSURE /1012MB/ RESIDES OVER THE REGION EARLY
THIS MORNING. MODERATELY STG...MID/UPPER WARM ADVECTION WAS
RESPONSIBLE CREATING AN EXTENSIVE /AND THICK/ SHIELD OF ALTO CU AND
CIRROSTRATUS OVER THE STATE.
THE WESTERN EDGE OF THIS MID AND HIGH CLOUD SHIELD /NEAR THE
OHIO/PENN BORDER AT 09Z/ WILL CONTINUE TO SLIDE TO THE EAST AT
APPROX 20KT...AND REACH A LINE FROM KELM...TO KUNV AND KAOO BY
15-16Z TDY...AND 17-19Z ACROSS THE WEST BRANCH AND MID SUSQ VALLEY.
MIN TEMPS AROUND SUNRISE WILL HAVE QUITE A TIGHT RANGE OF ONLY ABOUT
6-7 DEG F /U50S TO MID 60S/ FROM THE NORMALLY COLDER NW MTNS...TO
THE LOWER SUSQ VALLEY.
THE UPPER SHORTWAVE WITH IT/S PRECEDING WARM ADVECTION ALOFT AND
ITS BKN MID AND HIGH CLOUD DECK WILL BE PASSING EAST OF THE AREA
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. BEHIND THIS
FEATURE...06Z RUC SUPPORTS A MSUNNY MORNING ACROSS THE WESTERN
MTNS...WITH INCREASING/LESS FILTERED SUNSHINE FOR THE AFTERNOON
ACROSS THE SE HALF OF THE CWA.
THE SUNSHINE AND MDL 8H TEMPS ARND 17C WILL ALLOW TEMPS TO CLIMB
QUICKLY INTO THE 80S BY AFTN...WITH THE LOWER SUSQ VALLEY NEARING
90F.
AFTER AN APPROX 7-8 HOUR PERIOD OF TRANQUIL CONDITIONS FOR THE FIRST
HALF OF THE DAYLIGHT HOURS...CU WILL INCREASE AND GROW VERTICALLY
DURING THE AFTN...AS A POCKET OF STEEP MID LEVEL LAPSE RATES /AROUND
7C PER KM/ OVERSPREADS THE CWA AHEAD OF NEXT SHORTWAVE AND ASSOC
COLD FRONT.
00Z-03Z MDLS/SREF GENERATE A RESPECTABLE AMOUNT OF CAPE BY LATE IN
THE AFTERNOON TODAY. THE BEST CHC OF TSRA WILL BE ACROSS THE NCENT
AND NW MTNS...WHERE LARGE SCALE FORCING AND DECENT UPPER LEVEL
DIVERGENCE...WILL COMBINE WITH MDTLY STG LLVL THETA-E CONVERGENCE
AND MID-LEVEL WESTERLY WINDS.
SFC DEW POINTS MAINLY IN THE LOWER TO MID 60S...WILL HELP TO CREATE
MLCAPES AROUND 1500 J/KG THIS AFTERNOON INTO EARLY THIS EVENING.
THIS INSTABILITY COMBINED WITH THE MODERATE WIND SHEAR COULD BE
ENOUGH TO SUPPORT ISOLD SVR MULTI-CELL TSTORMS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
WEAK LLVL RIDGING MOVES IN FROM THE WEST AS THE BEST UPPER LEVEL
DIVERGENCE WANES/SHIFTS TWD THE MID ATLANTIC COAST. SCATTERED
SHRA/TSRA WILL OCCUR MAINLY BEFORE MIDNIGHT...BUT ISOLATED SHRA/TSRA
WILL STILL BE POSSIBLE LATE AS THE LLVL FRONTAL BOUNDARY STALLS OUT
TEMPORARILY FROM ABOUT KAVP TO KUNV AND KPIT...AND MU/ML CAPES
REMAIN QUITE HIGH GIVEN THE LINGERING POCKET OF STEEP LAPSE RATES
ALOFT AND MOIST BLYR WITH DEWPOINTS IN THE LOWER TO MID 60S ACROSS
THE CENTRAL ZONES...AND PERHAPS AROUND A MUGGY 70F IN THE
SOUTHEAST.
WEAK HIGH BUILDS INTO THE AREA BY LATE FRIDAY AS THE FRONTAL
BOUNDARY LIFTS NORTH AS A WARM FRONT INTO NEW YORK STATE. SW FLOW AT
THE SFC AND ALOFT WILL MAINTAIN VERY WARM AND SOMEWHAT HUMID
CONDITIONS...ESP IN THE SOUTH WHERE TEMPS WILL TOP OUT IN THE U80S
TO LOWER 90S WITH SFC DEWPOINTS IN THE U60S TO AROUND 70F.
HIGH TEMPS IN ALL AREAS FRIDAY WILL ONCE AGAIN BE 10-12F ABOVE
NORMAL.
GRIDDED SKY COVER /CU TOPPED BY PERIODS OF CIRRUS/ WILL AVERAGE
AROUND 50 PERCENT THROUGH THE DAY FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
CLOUDS THICKEN UP WITH SHRA/TSRA BECOMING LIKELY WELL AFTER MIDNIGHT
ACROSS THE ALLEGHENY PLATEAU OF NRN AND WRN PENN.
LOW LEVEL WIND SHEAR COULD IMPACT AVIATION AND BE FELT ACRS THE
HIGHER TERRAIN FRIDAY NIGHT INTO SATURDAY...AS THE SSW FLOW IN THE
1-2 KFT AGL LAYER STRENGTHENS TO 35-40 KTS.
DEEP LOW FCST TO DRAG A WARM FRONT...THEN A COLD FRONT ACROSS THE
AREA ON SAT. MODELS DO NOT CLOSE LOW OFF NOW...BUT STILL LOOKS WET.
SOME CHC OF STRONG TO PERHAPS SEVERE STORMS ACROSS THE EAST LATE.
LESS CHC FOR WIDESPREAD HEAVY RAIN NOW...AS SYSTEM DOES NOT CLOSE
OFF AND GO NEGATIVE. STILL WILL BE WET FOR MUCH OF THE DAY.
RATHER STRONG UPPER LVL LOW MOVING ACROSS THE REGION ON SUNDAY...
THUS EXPECT CU TO DEVELOP FAST...LIMIT MAX TEMPS...AND RESULT IN
SHOWERS AND STORMS. DID LOWER TEMPS A TAD FOR SOME PERIODS AFTER
SATURDAY.
WITH THE UPPER LVL LOW MOVING OUT FASTER NOW...SHOULD BE DRY ON
MONDAY.
TUE AND WED LOOK DRY WITH HIGH PRESSURE OVER WV.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
CURRENT SATELLITE HAS WIDESPREAD MIDDLE TO HIGH CLOUDS MOVING OVER
THE STATE. THIS WILL REDUCE THE PROBABILITIES FOR FOG OVERNIGHT AND
THIS MORNING. CURRENT DEW POINT DEPRESSIONS ARE IN THE SINGLE
DIGITS...WHICH IS A GOOD SIDE FOR FOG. WITH THE CALM WINDS ACROSS
THE BOARD AND AN INVERSION IN PLACE...PATCHY FOG IS CERTAINLY
PROBABLY THROUGH ANY MID TO HIGH CLOUDS WILL REDUCE ITS INTENSITY.
SO EXPECT TO SEE THE DEVELOPMENT OF SOME VALLEY FOG BY 2-4 AM AND
CONTINUE A FEW HOURS AFTER SUNRISE. VIZ WILL BE THE PRIMARY
RESTRICTIONS UNTIL CONDITIONS LIFT...IN THE 1-3 MILE
RANGE...THOUGH UNV COULD SEE IFR OR LOWER CIGS. CONDITIONS WILL
CONTINUE UNTIL MID TO LATE MORNING.
THURS AFTERNOON WILL SEE SCATTERED CONVECTION BECOMING THE THREAT
WITH LOCALIZED RESTRICTIONS IN THE SHOWERS/STORMS AS WELL AS THE
POTENTIAL FOR ISOLATED STRONG WIND GUSTS IN STRONGER
THUNDERSTORMS.
OUTLOOK...
THU...MAINLY VFR AFTER MORNING FOG. SCT SHOWERS/THUNDERSTORMS
DEVELOPING BY AFTERNOON AND LASTING INTO EVENING.
FRI...MAINLY VFR.
SAT...DETERIORATING CONDITIONS WITH THE APPROACH OF A WAVE OF LOW
PRESSURE.
SUN...MVFR EARLY...IMPROVING DURING THE DAY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/MARTIN
AVIATION...CERU/GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
351 PM EDT THU SEP 6 2012
.SYNOPSIS...
SLIGHTLY DRIER AIR WILL PREVAIL ACROSS OUR REGION ON FRIDAY UNDER
WEAK HIGH PRESSURE. A STRONG COLD FRONT WILL MOVE ACROSS THE
AREA SATURDAY AND SATURDAY NIGHT WITH DRY AIR OVERSPREADING THE
REGION ON SUNDAY. DRY HIGH PRESSURE WILL SETTLE OVER THE REGION FOR
MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
430 PM EDT UPDATE...THE BIGGEST CHANGE FOR THE UPDATE INCLUDED
ADDING A NUMEROUS -SHRA/TS AREA ACROSS THE EASTERN UPSTATE AND INTO
THE NC PIEDMONT AROUND KCLT...PER THE LATEST 88D TRENDS AND SFC
CONVERGENCE FIELDS. THERE COULD BE SOME TRAINING HYDRO ISSUES LATER
ON...DEPENDIN ON TRANSLATION OF THE UPPER TROF EASTWARD. SKY COVER
WAS ADJUSTED USING THE LATEST VSBL LOOP AND INTERPOLATED HR/LY
THROUGH THE EVENING. MINOR CHANGES WERE MADE TO TEMPS/TDS...MAINLY
ACROSS THE EASTERN PIEDMONT WHERE CONVECTIVE CLOUD COVER HAS KEPT
HR/LY VALUES LOWER THAN FORECASTED.
THE 16 UTC RAP AND WATER VAPOR IMAGERY CONTINUE TO INDICATE A WELL
DEFINED SHORT WAVE TROF SLOWLY PROGRESSING ACROSS THE NC MTNS. AHEAD
OF THE TROUGH...A STOUT AREA OF PVA EXITS OVER THE FOOTHILLS AND
WESTERN PIEDMONT. THE WAVE WILL CONTINUE TO SLOWLY TRANSLATE TO THE
ESE OVER THE NEXT SEVERAL HOURS. DEWPOINTS ARE QUITE HIGH OVER THE
WESTERN CAROLINAS AND NE GA...AND NOW THAT TEMPS HAVE WARMED INTO
THE L-M80S...SBCAPE VALUES HAVE RISEN TO 2000 J/KG OR HIGH IN MANY
AREAS. THIS HAS RESULTED IN THE DEVELOPMENT OF SHRA/TSTMS OVER THE
ERN UPSTATE AND SRN NC PIEDMONT. THE ACTIVITY SHOULD INCREASE IN
COVERAGE OVER THE NEXT COUPLE HOURS...THEN MOVE EAST OF THE REGION
BY EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS A DCAPE MINIMUM
ACROSS THE REGION. FREEZING LEVELS ARE ALSO OVER 15KFT.
THEREFORE...NEITHER DAMAGING WINDS OR NOR HAIL WILL BE MUCH OF A
THREAT WITH STORMS THIS AFTN. THE STORMS SHOULD NOT BECOME VERY
ORGANIZED AND 30 TO 40 PERCENT COVERAGE...MAINLY OVER THE ERN
ZONES...STILL LOOKS REASONABLE. THE EXCEPTION TO THIS COULD BE THE
SRN NC PIEDMONT WHERE THE WAVE IS ALSO RESULTING IS INCREASED LLVL
CONVERGENCE.
LATE TONIGHT WIDESPREAD DENSE VALLEY FOG IS EXPECTED OVER THE NC
MTNS. WITH THE MID-LEVELS DRY OUT...FOR SHOULD ALSO BE A LITTLE MORE
WIDESPREAD ACROSS THE FOOTHILLS AND PIEDMONT...PARTICULARLY ALONG
THE LARGER RIVER VALLEYS.
SLIGHTLY DRIER AIR WILL WORK INTO THE REGION TOMORROW. A SHORT WAVE
RIDGE WILL ALSO SLOWLY TRANSLATE ACROSS THE FA. WITH MUCH DRIER AIR
ALOFT AND WARM H7 TEMPS CONVECTION WILL HAVE DIFFICULTLY DEVELOPING
TOMORROW AND I HAVE A DRY FORECAST FOR THE FOOTHILLS AND PIEDMONT.
ISOLATED STORMS ARE POSSIBLE OVER THE MTNS...PARTICULARLY OVER THE
HIGHER ELEVATIONS. WITH DRIER AIR AND LIGHT DOWNSLOPE
FLOW...TEMPERATURES WILL RISE INTO THE L90S ACROSS MUCH OF FOOTHILLS
AND PIEDMONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
COLD FROPA AND ASSOCIATED PRECIPITATION ARE THE BIG CONCERN FOR
FRIDAY NIGHT AND SATURDAY. 850MB WINDS WERE STRONGER ON 00Z NAM THAN
ON 06Z GFS...WHICH LED THE NAM TO PRODUCE STRONGER THETA-E ADVECTION
AND MOISTURE TRANSPORT AHEAD OF THE FRONT. 12Z NAM HAS WEAKER WINDS
MORE IN LINE WITH THE GFS AND ITS MOISTURE FIELDS REFLECT THE WEAKER
ADVECTION. DECENT AGREEMENT BETWEEN MODELS IN TIMING OF
FROPA...WHICH APPEARS TO OCCUR BETWEEN 12Z AND 18Z. PRECIPITABLE
WATER VALUES INCREASE AS THE FRONT ENTERS THE PIEDMONT...BUT THE
VALUES OVER THE MOUNTAINS ARE MORE EXTREME WITH RESPECT TO
CLIMATOLOGY. IF THE DYNAMICS ALONG THE FRONT WERE MORE IMPRESSIVE I
WOULD BE INCLINED TO GO WITH HIGHER QPF...BUT KEPT IT IN CHECK FOR
NOW.
WITH THE FRONT MOVING THROUGH EARLY IN THE DAY...INSTABILITY WILL BE
LIMITED...BUT FORECAST SOUNDINGS INDICATE ENOUGH CAPE TO WARRANT A
THUNDER MENTION. HOWEVER THE BETTER CHANCES FOR THUNDER WILL BE OVER
THE SC PIEDMONT ZONES DURING THE AFTERNOON AS THAT AREA WILL HAVE
MORE TIME TO DESTABILIZE.
COLD ADVECTION AND SUBSIDENCE SET IN QUICKLY BEHIND THE FRONT AND
MODELS AGREE PRECIP SHOULD END BY LATE SATURDAY EVENING. COULD SEE
SOME STRONG GAP WINDS IN THE MOUNTAIN VALLEYS OVERNIGHT SATURDAY
NIGHT GIVEN STRONG WINDS IN 1000-3000 FT LAYER AND WEAK INVERSION
PROFILE EXPECTED WITH PARTLY CLOUDY SKIES STILL IN PLACE.
SUNDAY LOOKS TO BE REFRESHINGLY COOLER AND LESS HUMID
WITH HIGHS IN THE MID 70S OVER THE MOUNTAINS TO THE LOWER 80S OVER
THE PIEDMONT. ONE ITEM OF NOTE IS THAT THE 00Z EC DEVELOPS THE
TROUGH INTO A CUTOFF UPPER LOW OVER THE NORTHEAST CONUS...WITH A
WEAK LOBE OF VORTICITY REACHING THE MOUNTAINS LATE SUNDAY. HOWEVER
THE MODEL DOES NOT PRODUCE ANY PRECIP AND THE WHOLE TROUGH IS LONG
GONE ON THE GFS AT THIS TIME ANYWAY...SO STILL FEEL PRETTY CONFIDENT
WITH DRY FORECAST SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM EDT THURSDAY...BY 00Z MONDAY ALL MODELS ARE INDICATING
THAT DRY AIR WILL BE WELL ESTABLISHED AS THE AXIS OF THE UPPER
TROUGH WILL BE OVER OUR AREA AND MOVING EAST. COOLER CANADIAN HIGH
PRESSURE WILL BE MOVING FROM THE MISSISSIPPI VALLEY SUNDAY EVENING
TO BE POSITIONED OVER WEST VIRGINIA BY AROUND 00Z TUESDAY. HIGH
PRESSURE WILL SLOWLY SLIDE OFF THE EAST COAST IN MID WEEK AS THE
NEXT COLD FRONT APPROACHES FROM THE NORTHWEST. HPC HAS THE FRONT
OVER THE OHIO RIVER THURSDAY MORNING AS THAT POSITION MORE CLOSELY
FOLLOWS THE ECMWF WHICH HAS A MUCH MORE SHALLOW TROUGH CROSSING THE
GREAT LAKES AND HAS VERY LITTLE MOISTURE. THE GFS IS MUCH SLOWER
WITH A SHARPER UPPER TROUGH AND DEEPER MOISTURE. THEREFORE...ONLY
INCREASING THE CLOUDS A BIT OVER THE MOUNTAINS AT THE END OF THE
CURRENT FORECAST WHICH AT THIS POINT IS THURSDAY NIGHT.
TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL DURING THE FIRST
HALF OF THE WEEK AND WARMING TO JUST BELOW NORMAL BY THURSDAY.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AT KCLT...SCT SHRA ARE BEGINNING TO DEVELOP OVER THE UPSTATE AND WRN
NC PIEDMONT ALONG A LINE FROM ABOUT 20 MILES NW OF THE AIRFIELD TO
40 MILES TO IT/S SOUTHWEST. WITH AN UNSTABLE ATMOSPHERE AND A WELL
DEFINED UPPER TROUGH APPROACHING...THE SHRA SHOULD GROW INTO TSTMS
AND MOVE INTO THE VCNTY OF THE AIRFIELD BY 19 UTC. THE CONVECTION
SHOULD LAST 3 TO 4 HOURS BEFORE MOVING EAST OF THE REGION BY 22-23
UTC. WINDS WILL BE OUT OF THE SW THIS AFTN AND WILL BE LIGHT
OVERNIGHT. AREAS OF MVFR FOG ARE LIKELY LATER TONIGHT. IN
FACT...DENSE FOG IS A GOOD BET IN PARTS OF THE WESTERN
PIEDMONT...BUT THIS WON/T BE INCLUDED AT KCLT AS THE AIRFIELD
TYPICALLY IS ONE OF THE LAST PLACES TO FOG UP.
ELSEWHERE...SCT SHRA WERE BEGINNING TO DEVELOP ACROSS THE REGION AT
ISSUANCE TIME. COVERAGE AND INTENSITY SHOULD INCREASE OVER THE NEXT
COUPLE HOURS AS AN UPPER LEVEL TROUGH CROSSES THE REGION.
HOWEVER...THE CONVECTION WILL BE SCT ENOUGH THAT ONLY VCTS WILL BE
CARRIED AT THE UPSTATE AND FOOTHILL TAF SITES. OF COURSE TEMPO OR
PREVAILING WILL BE ADDED TO ANY SITES THAT LOOK TO BE IMMEDIATELY
THREATENED. ONCE THE TROUGH PASSES...THERE SHOULD BE LESS MID AND
HIGH LEVEL CLOUDS OVERNIGHT. THIS WILL FAVOR THE DEVELOPMENT OF
DENSE VALLEY FOG IN THE NC MTNS...AS WELL AS SOME OF THE NON-MTN
RIVER VALLEYS. LIFR FOG HAS BEEN CARRIED AT KAND AND KHKY WITH
PREVAILING VLIFR AT KAVL.
OUTLOOK...BRIEF DRYING FROM THE WEST IS EXPECTED INTO FRIDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST ON SATURDAY AND
MOVE EAST OF THE AREA ON SUNDAY. A LINE OF THUNDERSTORMS IS POSSIBLE
WITH THE FRONT ON SATURDAY. DRY AUTUMNAL HIGH PRES WILL DOMINATE THE
AREA EARLY NEXT WEEK.
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...DEO
NEAR TERM...MCAVOY/SBK
SHORT TERM...JW
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
234 PM EDT THU SEP 6 2012
.SYNOPSIS...
SLIGHTLY DRIER AIR WILL PREVAIL ACROSS OUR REGION ON FRIDAY UNDER
WEAK HIGH PRESSURE. A STRONG COLD FRONT WILL MOVE ACROSS THE
AREA SATURDAY AND SATURDAY NIGHT WITH DRY AIR OVERSPREADING THE
REGION ON SUNDAY. DRY HIGH PRESSURE WILL SETTLE OVER THE REGION FOR
MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE 16 UTC RAP AND WATER VAPOR IMAGERY CONTINUE TO INDICATE A WELL
DEFINED SHORT WAVE TROF SLOWLY PROGRESSING ACROSS THE NC MTNS. AHEAD
OF THE TROUGH...A STOUT AREA OF PVA EXITS OVER THE FOOTHILLS AND
WESTERN PIEDMONT. THE WAVE WILL CONTINUE TO SLOWLY TRANSLATE TO THE
ESE OVER THE NEXT SEVERAL HOURS. DEWPOINTS ARE QUITE HIGH OVER THE
WESTERN CAROLINAS AND NE GA...AND NOW THAT TEMPS HAVE WARMED INTO
THE L-M80S...SBCAPE VALUES HAVE RISEN TO 2000 J/KG OR HIGH IN MANY
AREAS. THIS HAS RESULTED IN THE DEVELOPMENT OF SHRA/TSTMS OVER THE
ERN UPSTATE AND SRN NC PIEDMONT. THE ACTIVITY SHOULD INCREASE IN
COVERAGE OVER THE NEXT COUPLE HOURS...THEN MOVE EAST OF THE REGION
BY EARLY EVENING. THE LATEST SPC MESOANALYSIS SHOWS A DCAPE MINIMUM
ACROSS THE REGION. FREEZING LEVELS ARE ALSO OVER 15KFT.
THEREFORE...NEITHER DAMAGING WINDS OR NOR HAIL WILL BE MUCH OF A
THREAT WITH STORMS THIS AFTN. THE STORMS SHOULD NOT BECOME VERY
ORGANIZED AND 30 TO 40 PERCENT COVERAGE...MAINLY OVER THE ERN
ZONES...STILL LOOKS REASONABLE. THE EXCEPTION TO THIS COULD BE THE
SRN NC PIEDMONT WHERE THE WAVE IS ALSO RESULTING IS INCREASED LLVL
CONVERGENCE.
LATE TONIGHT WIDESPREAD DENSE VALLEY FOG IS EXPECTED OVER THE NC
MTNS. WITH THE MID-LEVELS DRY OUT...FOR SHOULD ALSO BE A LITTLE MORE
WIDESPREAD ACROSS THE FOOTHILLS AND PIEDMONT...PARTICULARLY ALONG
THE LARGER RIVER VALLEYS.
SLIGHTLY DRIER AIR WILL WORK INTO THE REGION TOMORROW. A SHORT WAVE
RIDGE WILL ALSO SLOWLY TRANSLATE ACROSS THE FA. WITH MUCH DRIER AIR
ALOFT AND WARM H7 TEMPS CONVECTION WILL HAVE DIFFICULTLY DEVELOPING
TOMORROW AND I HAVE A DRY FORECAST FOR THE FOOTHILLS AND PIEDMONT.
ISOLATED STORMS ARE POSSIBLE OVER THE MTNS...PARTICULARLY OVER THE
HIGHER ELEVATIONS. WITH DRIER AIR AND LIGHT DOWNSLOPE
FLOW...TEMPERATURES WILL RISE INTO THE L90S ACROSS MUCH OF FOOTHILLS
AND PIEDMONT.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
COLD FROPA AND ASSOCIATED PRECIPITATION ARE THE BIG CONCERN FOR
FRIDAY NIGHT AND SATURDAY. 850MB WINDS WERE STRONGER ON 00Z NAM THAN
ON 06Z GFS...WHICH LED THE NAM TO PRODUCE STRONGER THETA-E ADVECTION
AND MOISTURE TRANSPORT AHEAD OF THE FRONT. 12Z NAM HAS WEAKER WINDS
MORE IN LINE WITH THE GFS AND ITS MOISTURE FIELDS REFLECT THE WEAKER
ADVECTION. DECENT AGREEMENT BETWEEN MODELS IN TIMING OF
FROPA...WHICH APPEARS TO OCCUR BETWEEN 12Z AND 18Z. PRECIPITABLE
WATER VALUES INCREASE AS THE FRONT ENTERS THE PIEDMONT...BUT THE
VALUES OVER THE MOUNTAINS ARE MORE EXTREME WITH RESPECT TO
CLIMATOLOGY. IF THE DYNAMICS ALONG THE FRONT WERE MORE IMPRESSIVE I
WOULD BE INCLINED TO GO WITH HIGHER QPF...BUT KEPT IT IN CHECK FOR
NOW.
WITH THE FRONT MOVING THROUGH EARLY IN THE DAY...INSTABILITY WILL BE
LIMITED...BUT FORECAST SOUNDINGS INDICATE ENOUGH CAPE TO WARRANT A
THUNDER MENTION. HOWEVER THE BETTER CHANCES FOR THUNDER WILL BE OVER
THE SC PIEDMONT ZONES DURING THE AFTERNOON AS THAT AREA WILL HAVE
MORE TIME TO DESTABILIZE.
COLD ADVECTION AND SUBSIDENCE SET IN QUICKLY BEHIND THE FRONT AND
MODELS AGREE PRECIP SHOULD END BY LATE SATURDAY EVENING. COULD SEE
SOME STRONG GAP WINDS IN THE MOUNTAIN VALLEYS OVERNIGHT SATURDAY
NIGHT GIVEN STRONG WINDS IN 1000-3000 FT LAYER AND WEAK INVERSION
PROFILE EXPECTED WITH PARTLY CLOUDY SKIES STILL IN PLACE.
SUNDAY LOOKS TO BE REFRESHINGLY COOLER AND LESS HUMID
WITH HIGHS IN THE MID 70S OVER THE MOUNTAINS TO THE LOWER 80S OVER
THE PIEDMONT. ONE ITEM OF NOTE IS THAT THE 00Z EC DEVELOPS THE
TROUGH INTO A CUTOFF UPPER LOW OVER THE NORTHEAST CONUS...WITH A
WEAK LOBE OF VORTICITY REACHING THE MOUNTAINS LATE SUNDAY. HOWEVER
THE MODEL DOES NOT PRODUCE ANY PRECIP AND THE WHOLE TROUGH IS LONG
GONE ON THE GFS AT THIS TIME ANYWAY...SO STILL FEEL PRETTY CONFIDENT
WITH DRY FORECAST SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM EDT THURSDAY...BY 00Z MONDAY ALL MODELS ARE INDICATING
THAT DRY AIR WILL BE WELL ESTABLISHED AS THE AXIS OF THE UPPER
TROUGH WILL BE OVER OUR AREA AND MOVING EAST. COOLER CANADIAN HIGH
PRESSURE WILL BE MOVING FROM THE MISSISSIPPI VALLEY SUNDAY EVENING
TO BE POSITIONED OVER WEST VIRGINIA BY AROUND 00Z TUESDAY. HIGH
PRESSURE WILL SLOWLY SLIDE OFF THE EAST COAST IN MID WEEK AS THE
NEXT COLD FRONT APPROACHES FROM THE NORTHWEST. HPC HAS THE FRONT
OVER THE OHIO RIVER THURSDAY MORNING AS THAT POSITION MORE CLOSELY
FOLLOWS THE ECMWF WHICH HAS A MUCH MORE SHALLOW TROUGH CROSSING THE
GREAT LAKES AND HAS VERY LITTLE MOISTURE. THE GFS IS MUCH SLOWER
WITH A SHARPER UPPER TROUGH AND DEEPER MOISTURE. THEREFORE...ONLY
INCREASING THE CLOUDS A BIT OVER THE MOUNTAINS AT THE END OF THE
CURRENT FORECAST WHICH AT THIS POINT IS THURSDAY NIGHT.
TEMPERATURES WILL BE A FEW DEGREES BELOW NORMAL DURING THE FIRST
HALF OF THE WEEK AND WARMING TO JUST BELOW NORMAL BY THURSDAY.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...SCT SHRA ARE BEGINNING TO DEVELOP OVER THE UPSTATE AND WRN
NC PIEDMONT ALONG A LINE FROM ABOUT 20 MILES NW OF THE AIRFIELD TO
40 MILES TO IT/S SOUTHWEST. WITH AN UNSTABLE ATMOSPHERE AND A WELL
DEFINED UPPER TROUGH APPROACHING...THE SHRA SHOULD GROW INTO TSTMS
AND MOVE INTO THE VCNTY OF THE AIRFIELD BY 19 UTC. THE CONVECTION
SHOULD LAST 3 TO 4 HOURS BEFORE MOVING EAST OF THE REGION BY 22-23
UTC. WINDS WILL BE OUT OF THE SW THIS AFTN AND WILL BE LIGHT
OVERNIGHT. AREAS OF MVFR FOG ARE LIKELY LATER TONIGHT. IN
FACT...DENSE FOG IS A GOOD BET IN PARTS OF THE WESTERN
PIEDMONT...BUT THIS WON/T BE INCLUDED AT KCLT AS THE AIRFIELD
TYPICALLY IS ONE OF THE LAST PLACES TO FOG UP.
ELSEWHERE...SCT SHRA WERE BEGINNING TO DEVELOP ACROSS THE REGION AT
ISSUANCE TIME. COVERAGE AND INTENSITY SHOULD INCREASE OVER THE NEXT
COUPLE HOURS AS AN UPPER LEVEL TROUGH CROSSES THE REGION.
HOWEVER...THE CONVECTION WILL BE SCT ENOUGH THAT ONLY VCTS WILL BE
CARRIED AT THE UPSTATE AND FOOTHILL TAF SITES. OF COURSE TEMPO OR
PREVAILING WILL BE ADDED TO ANY SITES THAT LOOK TO BE IMMEDIATELY
THREATENED. ONCE THE TROUGH PASSES...THERE SHOULD BE LESS MID AND
HIGH LEVEL CLOUDS OVERNIGHT. THIS WILL FAVOR THE DEVELOPMENT OF
DENSE VALLEY FOG IN THE NC MTNS...AS WELL AS SOME OF THE NON-MTN
RIVER VALLEYS. LIFR FOG HAS BEEN CARRIED AT KAND AND KHKY WITH
PREVAILING VLIFR AT KAVL.
OUTLOOK...BRIEF DRYING FROM THE WEST IS EXPECTED INTO FRIDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST ON SATURDAY AND
MOVE EAST OF THE AREA ON SUNDAY. A LINE OF THUNDERSTORMS IS POSSIBLE
WITH THE FRONT ON SATURDAY. DRY AUTUMNAL HIGH PRES WILL DOMINATE THE
AREA EARLY NEXT WEEK.
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...DEO
NEAR TERM...MCAVOY
SHORT TERM...JW
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
155 PM EDT THU SEP 6 2012
.SYNOPSIS...
SLIGHTLY DRIER AIR WILL PREVAIL ACROSS OUR REGION ON FRIDAY UNDER
WEAK HIGH PRESSURE. A STRONG COLD FRONT WILL MOVE ACROSS THE
AREA SATURDAY AND SATURDAY NIGHT WITH DRY AIR OVERSPREADING THE
REGION ON SUNDAY. DRY HIGH PRESSURE WILL SETTLE OVER THE REGION FOR
MUCH OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 105 PM EDT...POPS HAVE BEEN TRIMMED BACK A LITTLE OVER THE
NEXT COUPLE HOURS. HOWEVER...THE SHORT WAVE IS BECOMING MUCH BETTER
DEFINED ON THE WATER VAPOR IMAGERY AND ON THE LATEST RUNS OF THE
RAP. WITH LAPS CAPE VALUES NOW OVER 2000 J/KG ACROSS THE
FOOTHILLS...CONVECTION SHOULD BEGIN TO FIRE OVER THE FORECAST AREA
WITHIN THE HOUR.
AS OF 1030 AM EDT...THE LATEST RAP MATCHES WELL WITH THE WATER VAPOR
IMAGERY DEPICTION OF A SHORT WAVE ALONG THE NC/TN LINE. THIS FEATURE
WILL GRADUALLY MOVE EAST THROUGH THE DAY. THE NAM CURRENTLY HAS TOO
MUCH CONVECTION OVER THE WRN PART OF THE FA WITH THIS FEATURE AS
DOES THE RAP. THERE IS QUITE A BIT OF LOW CLOUD COVER ACROSS THE
FOOTHILLS AND PIEDMONT ATTM WHICH IS CUTTING OFF SFC HEATING. THIS
WILL RESULT IN CONTINUED SUPPRESSION OF CONVECTION INTO THE EARLY
AFTN. THEREAFTER...THE MODEL SOLUTIONS OF SCT CONVECTION DEVELOPING
OVER THE FOOTHILLS OR WESTERN PIEDMONT BY EARLY AFTN AND THEN
TRACKING EAST OF FA BY EARLY EVENING STILL LOOKS GOOD.
TO ACCOUNT FOR THESE TRENDS I/VE CUT BACK POPS THROUGH 17 UTC.
THEREAFTER I HAVE MUCH THE SAME WEATHER AND POP GRIDS THAT THE MID
SHIFT HAD.
AS OF 700 AM EDT...THE MID AND HIGH CLOUDS OVER THE REGION AHEAD OF
AN APPROACHING H5 SHORTWAVE HAVE THINNED A BIT...BUT THIS HAS
PERMITTED LOW STRATUS TO BECOME A BIT MORE WIDESPREAD...SO THERE IS
NO NET CHANGE IN THE SKY COVER. SHOWER COVERAGE IS SLOWLY RAMPING UP
OVER THE MTNS AS UPPER DPVA STARTS TO MOVE IN. THE MOST POTENT VORT
MAX IN THE UPSTREAM SHORTWAVE TROUGH SHOULD CROSS THE SRN
APPALACHIANS MAINLY THIS MORNING AND THEN MOVE OUT OVER THE PIEDMONT
THROUGH THE AFTN OR EARLY EVENING HOURS. WESTERLY DOWNSLOPING FLOW
AT LOW LEVELS MAY INITIALLY KEEP PRECIPITATION COVERAGE LOW EAST OF
THE MTNS THIS MORNING...BUT THE PASSING UPPER SUPPORT ALONG WITH
DEVELOPING LEE TROUGHING NEAR THE SURFACE SHOULD PROVIDE ENOUGH LIFT
FOR SCATTERED CONVECTION THIS AFTN. IN ADDITION TO THE
DOWNSLOPE...GRADUAL MID AND UPPER LEVEL DRYING IN THE SOUNDINGS
COULD LIMIT POPS SOMEWHAT. WILL THUS HEDGE TOWARD THE DRIER GFS
BASED MOS FOR POPS THIS AFTN. THE MID LEVEL DRYING...HOWEVER...COULD
INCREASE THE MICROBURST THREAT WITH ANY TSTMS THAT DO MANAGE TO
DEVELOP OVER THE PIEDMONT. IN ADDITION...MAX TEMPERATURES SHOULD BE
A COUPLE OF DEGREES WARMER THAN WED AFTN MOST AREAS. THIS WILL ADD
TO THE PIEDMONT INSTABILITY WHERE SFC DEWPOINTS SHOULD LINGER AROUND
70 DEGREES THROUGH LATE DAY.
STRONGER DRYING FROM THE TOP DOWN IS EXPECTED TONIGHT AS FLOW TURNS
NW TO N THROUGH A DEEP LAYER. THE BOUNDARY LAYER...HOWEVER...SHOULD
REMAIN FAIRLY MOIST TO CREATE THE POTENTIAL FOR FOG/VSBY PROBLEMS
OVERNIGHT. MIN TEMPS WILL LIKELY BE A CATEGORY COOLER THAN IN RECENT
DAYS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 245 AM THURSDAY...THE ATMOSPHERE IS PROGGED TO DRY OUT
CONSIDERABLY ON FRIDAY...WITH FORECAST SOUNDING PWATS DECREASING TO
AROUND ONE INCH BY AFTERNOON. MEANWHILE...A LOW AMPLITUDE UPPER
RIDGE AXIS WILL NOSE INTO THE REGION FROM THE SOUTHWEST. THESE
FACTORS WILL RESULT IN ONE OF THE LOWEST POP DAYS WE/VE SEEN IN SOME
TIME. NEVERTHELESS...STRONG INSOLATION (MAX TEMPS AROUND 90 EXPECTED
IN THE PIEDMONT) WILL ALLOW FOR MODERATE DESTABILIZATION...WHICH
SHOULD SUPPORT SOME HIGH TERRAIN CONVECTION BY LATE AFTERNOON.
FORECAST SOUNDINGS DEPICT A WEAK MID-LEVEL SUBSIDENCE INVERSION IN
THE PIEDMONT...SO IT IS UNCERTAIN AS TO HOW FAR INTO THE FOOTHILLS/
PIEDMONT THE ATMOSPHERE WILL BE ABLE TO SUSTAIN CONVECTION. SLIGHT
CHANCE POPS WERE INHERITED OUTSIDE THE MTNS...AND THIS STILL SEEMS
REASONABLE.
CONVECTION SHOULD DISSIPATE FATHER QUICKLY FRIDAY EVENING.
HOWEVER...STRONG HEIGHT FALLS WILL BE OCCURRING DURING THIS TIME
WEST THROUGH NORTHWEST OF THE AREA...DRIVING A STRONG COLD FRONT
TOWARD THE APPALACHIANS FRIDAY NIGHT. THERE ARE SLIGHT TIMING
DIFFERENCES IN THE OPERATIONAL MODELS...WITH THE NAM BEING ABOUT 3
HOURS FASTER THAN THE GFS. WE HAVE FAVORED THE SLIGHTLY FASTER
NAM...AS THERE WILL PROBABLY BE A MAJOR CONVECTIVE/COLD POOL
COMPONENT TO THE FRONTAL BAND...WHICH ALWAYS SEEMS TO RESULT IN
FASTER TIMING THAN DEPICTED BY THE MODELS. SPEAKING OF WHICH...
SATURDAY COULD BE AN INTERESTING CONVECTIVE DAY FOR OUR AREA...AS
THE COLD FRONT SEEMS DESTINED TO SWEEP ACROSS THE PIEDMONT DURING
PEAK HEATING TIME. THERE MAY BE EXTENSIVE MORNING HIGH CLOUDS AND
MID-LEVEL LAPSE RATES WILL BE WEAK...WHICH WOULD LIKELY LIMIT CAPE
VALUES TO WELL UNDER 2000 J/KG. NEVERTHELESS...IT APPEARS SHEAR WILL
BE FAIRLY STRONG...PARTICULARLY IN THE LOWER LEVELS...SO THERE IS A
LOW-END ORGANIZED SEVERE WEATHER THREAT.
CHANCE POPS WILL BEGIN OVER THE SOUTHWEST NC MTNS LATE FRIDAY
NIGHT...INCREASING TO LIKELY ACROSS THE MTNS BY EARLY AFTERNOON...
WITH HIGH CHANCES EXTENDING TO THE EAST DURING MID/LATE AFTERNOON.
THE MODEL CONSENSUS IS TO SWEEP ALL CONVECTION EAST OF THE AREA BY
00Z SUNDAY...SO POPS HAVE BEEN ADJUSTED DOWN SAT NIGHT THROUGH EARLY
SUNDAY. (SLIGHT/LOW CHANCES AT 00Z...DIMINISHING TO LESS THAN 20
PERCENT BY 12Z). COOL ADVECTION FLOW WILL RESULT IN MIN TEMPS ABOUT
A CAT BELOW NORMAL SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 130 AM EDT THURSDAY...L/WV TROUGH AXIS WITH DRY AND COOLER
NORTHERLY LLVL FLOW IS PROGGED TO BE ATOP THE REGION ON MONDAY.
TEMPERATURES WILL START OFF THE PERIOD 2-3 CATEGORIES BELOW CLIMO.
SFC RIDGE AXIS WILL BUILD IN ON TUESDAY AS UPPER TROUGH AXIS
PROGRESSES OFFSHORE AND GIVES WAY TO NW FLOW ALOFT. CONTINUED DRY
CONDITIONS ARE EXPECTED WITH TEMPERATURES NEAR PERSISTENCE. DEEP
LAYERED RIDGING WILL THEN DEVELOP ACRS THE SE CONUS BY THE END OF THE
PERIOD AND MAX TEMPERATURES ON WEDNESDAY WILL MODERATE A FEW DEG F
BUT STILL AVERAGE BELOW NORMAL.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...SCT SHRA ARE BEGINNING TO DEVELOP OVER THE UPSTATE AND WRN
NC PIEDMONT ALONG A LINE FROM ABOUT 20 MILES NW OF THE AIRFIELD TO
40 MILES TO IT/S SOUTHWEST. WITH AN UNSTABLE ATMOSPHERE AND A WELL
DEFINED UPPER TROUGH APPROACHING...THE SHRA SHOULD GROW INTO TSTMS
AND MOVE INTO THE VCNTY OF THE AIRFIELD BY 19 UTC. THE CONVECTION
SHOULD LAST 3 TO 4 HOURS BEFORE MOVING EAST OF THE REGION BY 22-23
UTC. WINDS WILL BE OUT OF THE SW THIS AFTN AND WILL BE LIGHT
OVERNIGHT. AREAS OF MVFR FOG ARE LIKELY LATER TONIGHT. IN
FACT...DENSE FOG IS A GOOD BET IN PARTS OF THE WESTERN
PIEDMONT...BUT THIS WON/T BE INCLUDED AT KCLT AS THE AIRFIELD
TYPICALLY IS ONE OF THE LAST PLACES TO FOG UP.
ELSEWHERE...SCT SHRA WERE BEGINNING TO DEVELOP ACROSS THE REGION AT
ISSUANCE TIME. COVERAGE AND INTENSITY SHOULD INCREASE OVER THE NEXT
COUPLE HOURS AS AN UPPER LEVEL TROUGH CROSSES THE REGION.
HOWEVER...THE CONVECTION WILL BE SCT ENOUGH THAT ONLY VCTS WILL BE
CARRIED AT THE UPSTATE AND FOOTHILL TAF SITES. OF COURSE TEMPO OR
PREVAILING WILL BE ADDED TO ANY SITES THAT LOOK TO BE IMMEDIATELY
THREATENED. ONCE THE TROUGH PASSES...THERE SHOULD BE LESS MID AND
HIGH LEVEL CLOUDS OVERNIGHT. THIS WILL FAVOR THE DEVELOPMENT OF
DENSE VALLEY FOG IN THE NC MTNS...AS WELL AS SOME OF THE NON-MTN
RIVER VALLEYS. LIFR FOG HAS BEEN CARRIED AT KAND AND KHKY WITH
PREVAILING VLIFR AT KAVL.
OUTLOOK...BRIEF DRYING FROM THE WEST IS EXPECTED INTO FRIDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST ON SATURDAY AND
MOVE EAST OF THE AREA ON SUNDAY. A LINE OF THUNDERSTORMS IS POSSIBLE
WITH THE FRONT ON SATURDAY. DRY AUTUMNAL HIGH PRES WILL DOMINATE THE
AREA EARLY NEXT WEEK.
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...DEO
NEAR TERM...MCAVOY
SHORT TERM...JDL
LONG TERM...CSH
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
109 PM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL DRIFT ACROSS THE REGION TODAY FOLLOWED
BY SLIGHTLY DRIER AIR FOR FRIDAY. A STRONG COLD FRONT WILL MOVE
ACROSS THE AREA SATURDAY AND SATURDAY NIGHT WITH DRY AIR
OVERSPREADING THE REGION ON SUNDAY. DRY HIGH PRESSURE WILL SETTLE
OVER THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 105 PM EDT...POPS HAVE BEEN TRIMMED BACK A LITTLE OVER THE
NEXT COUPLE HOURS. HOWEVER...THE SHORT WAVE IS BECOMING MUCH BETTER
DEFINED ON THE WATER VAPOR IMAGERY AND ON THE LATEST RUNS OF THE
RAP. WITH LAPS CAPE VALUES NOW OVER 2000 J/KG ACROSS THE
FOOTHILLS...CONVECTION SHOULD BEGIN TO FIRE OVER THE FORECAST AREA
WITHIN THE HOUR.
AS OF 1030 AM EDT...THE LATEST RAP MATCHES WELL WITH THE WATER VAPOR
IMAGERY DEPICTION OF A SHORT WAVE ALONG THE NC/TN LINE. THIS FEATURE
WILL GRADUALLY MOVE EAST THROUGH THE DAY. THE NAM CURRENTLY HAS TOO
MUCH CONVECTION OVER THE WRN PART OF THE FA WITH THIS FEATURE AS
DOES THE RAP. THERE IS QUITE A BIT OF LOW CLOUD COVER ACROSS THE
FOOTHILLS AND PIEDMONT ATTM WHICH IS CUTTING OFF SFC HEATING. THIS
WILL RESULT IN CONTINUED SUPPRESSION OF CONVECTION INTO THE EARLY
AFTN. THEREAFTER...THE MODEL SOLUTIONS OF SCT CONVECTION DEVELOPING
OVER THE FOOTHILLS OR WESTERN PIEDMONT BY EARLY AFTN AND THEN
TRACKING EAST OF FA BY EARLY EVENING STILL LOOKS GOOD.
TO ACCOUNT FOR THESE TRENDS I/VE CUT BACK POPS THROUGH 17 UTC.
THEREAFTER I HAVE MUCH THE SAME WEATHER AND POP GRIDS THAT THE MID
SHIFT HAD.
AS OF 700 AM EDT...THE MID AND HIGH CLOUDS OVER THE REGION AHEAD OF
AN APPROACHING H5 SHORTWAVE HAVE THINNED A BIT...BUT THIS HAS
PERMITTED LOW STRATUS TO BECOME A BIT MORE WIDESPREAD...SO THERE IS
NO NET CHANGE IN THE SKY COVER. SHOWER COVERAGE IS SLOWLY RAMPING UP
OVER THE MTNS AS UPPER DPVA STARTS TO MOVE IN. THE MOST POTENT VORT
MAX IN THE UPSTREAM SHORTWAVE TROUGH SHOULD CROSS THE SRN
APPALACHIANS MAINLY THIS MORNING AND THEN MOVE OUT OVER THE PIEDMONT
THROUGH THE AFTN OR EARLY EVENING HOURS. WESTERLY DOWNSLOPING FLOW
AT LOW LEVELS MAY INITIALLY KEEP PRECIPITATION COVERAGE LOW EAST OF
THE MTNS THIS MORNING...BUT THE PASSING UPPER SUPPORT ALONG WITH
DEVELOPING LEE TROUGHING NEAR THE SURFACE SHOULD PROVIDE ENOUGH LIFT
FOR SCATTERED CONVECTION THIS AFTN. IN ADDITION TO THE
DOWNSLOPE...GRADUAL MID AND UPPER LEVEL DRYING IN THE SOUNDINGS
COULD LIMIT POPS SOMEWHAT. WILL THUS HEDGE TOWARD THE DRIER GFS
BASED MOS FOR POPS THIS AFTN. THE MID LEVEL DRYING...HOWEVER...COULD
INCREASE THE MICROBURST THREAT WITH ANY TSTMS THAT DO MANAGE TO
DEVELOP OVER THE PIEDMONT. IN ADDITION...MAX TEMPERATURES SHOULD BE
A COUPLE OF DEGREES WARMER THAN WED AFTN MOST AREAS. THIS WILL ADD
TO THE PIEDMONT INSTABILITY WHERE SFC DEWPOINTS SHOULD LINGER AROUND
70 DEGREES THROUGH LATE DAY.
STRONGER DRYING FROM THE TOP DOWN IS EXPECTED TONIGHT AS FLOW TURNS
NW TO N THROUGH A DEEP LAYER. THE BOUNDARY LAYER...HOWEVER...SHOULD
REMAIN FAIRLY MOIST TO CREATE THE POTENTIAL FOR FOG/VSBY PROBLEMS
OVERNIGHT. MIN TEMPS WILL LIKELY BE A CATEGORY COOLER THAN IN RECENT
DAYS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 245 AM THURSDAY...THE ATMOSPHERE IS PROGGED TO DRY OUT
CONSIDERABLY ON FRIDAY...WITH FORECAST SOUNDING PWATS DECREASING TO
AROUND ONE INCH BY AFTERNOON. MEANWHILE...A LOW AMPLITUDE UPPER
RIDGE AXIS WILL NOSE INTO THE REGION FROM THE SOUTHWEST. THESE
FACTORS WILL RESULT IN ONE OF THE LOWEST POP DAYS WE/VE SEEN IN SOME
TIME. NEVERTHELESS...STRONG INSOLATION (MAX TEMPS AROUND 90 EXPECTED
IN THE PIEDMONT) WILL ALLOW FOR MODERATE DESTABILIZATION...WHICH
SHOULD SUPPORT SOME HIGH TERRAIN CONVECTION BY LATE AFTERNOON.
FORECAST SOUNDINGS DEPICT A WEAK MID-LEVEL SUBSIDENCE INVERSION IN
THE PIEDMONT...SO IT IS UNCERTAIN AS TO HOW FAR INTO THE FOOTHILLS/
PIEDMONT THE ATMOSPHERE WILL BE ABLE TO SUSTAIN CONVECTION. SLIGHT
CHANCE POPS WERE INHERITED OUTSIDE THE MTNS...AND THIS STILL SEEMS
REASONABLE.
CONVECTION SHOULD DISSIPATE FATHER QUICKLY FRIDAY EVENING.
HOWEVER...STRONG HEIGHT FALLS WILL BE OCCURRING DURING THIS TIME
WEST THROUGH NORTHWEST OF THE AREA...DRIVING A STRONG COLD FRONT
TOWARD THE APPALACHIANS FRIDAY NIGHT. THERE ARE SLIGHT TIMING
DIFFERENCES IN THE OPERATIONAL MODELS...WITH THE NAM BEING ABOUT 3
HOURS FASTER THAN THE GFS. WE HAVE FAVORED THE SLIGHTLY FASTER
NAM...AS THERE WILL PROBABLY BE A MAJOR CONVECTIVE/COLD POOL
COMPONENT TO THE FRONTAL BAND...WHICH ALWAYS SEEMS TO RESULT IN
FASTER TIMING THAN DEPICTED BY THE MODELS. SPEAKING OF WHICH...
SATURDAY COULD BE AN INTERESTING CONVECTIVE DAY FOR OUR AREA...AS
THE COLD FRONT SEEMS DESTINED TO SWEEP ACROSS THE PIEDMONT DURING
PEAK HEATING TIME. THERE MAY BE EXTENSIVE MORNING HIGH CLOUDS AND
MID-LEVEL LAPSE RATES WILL BE WEAK...WHICH WOULD LIKELY LIMIT CAPE
VALUES TO WELL UNDER 2000 J/KG. NEVERTHELESS...IT APPEARS SHEAR WILL
BE FAIRLY STRONG...PARTICULARLY IN THE LOWER LEVELS...SO THERE IS A
LOW-END ORGANIZED SEVERE WEATHER THREAT.
CHANCE POPS WILL BEGIN OVER THE SOUTHWEST NC MTNS LATE FRIDAY
NIGHT...INCREASING TO LIKELY ACROSS THE MTNS BY EARLY AFTERNOON...
WITH HIGH CHANCES EXTENDING TO THE EAST DURING MID/LATE AFTERNOON.
THE MODEL CONSENSUS IS TO SWEEP ALL CONVECTION EAST OF THE AREA BY
00Z SUNDAY...SO POPS HAVE BEEN ADJUSTED DOWN SAT NIGHT THROUGH EARLY
SUNDAY. (SLIGHT/LOW CHANCES AT 00Z...DIMINISHING TO LESS THAN 20
PERCENT BY 12Z). COOL ADVECTION FLOW WILL RESULT IN MIN TEMPS ABOUT
A CAT BELOW NORMAL SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 130 AM EDT THURSDAY...L/WV TROUGH AXIS WITH DRY AND COOLER
NORTHERLY LLVL FLOW IS PROGGED TO BE ATOP THE REGION ON MONDAY.
TEMPERATURES WILL START OFF THE PERIOD 2-3 CATEGORIES BELOW CLIMO.
SFC RIDGE AXIS WILL BUILD IN ON TUESDAY AS UPPER TROUGH AXIS
PROGRESSES OFFSHORE AND GIVES WAY TO NW FLOW ALOFT. CONTINUED DRY
CONDITIONS ARE EXPECTED WITH TEMPERATURES NEAR PERSISTENCE. DEEP
LAYERED RIDGING WILL THEN DEVELOP ACRS THE SE CONUS BY THE END OF THE
PERIOD AND MAX TEMPERATURES ON WEDNESDAY WILL MODERATE A FEW DEG F
BUT STILL AVERAGE BELOW NORMAL.
&&
.AVIATION /17Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LOW CLOUD IR SATELLITE PRODUCT SHOWS IFR CIGS KNOCKING
ON THE DOOR AT CLT. WILL NEED TO CARRY TEMPO IFR FOR AT LEAST AN
HOUR. THERE IS NOT TOO MUCH MID OR HIGH CLOUD AT PRESENT ABOVE THE
PIEDMONT STRATUS LAYER...SO IT SHOULD BURN OFF FAIRLY QUICKLY.
ATTENTION WILL THEN TURN TO THE PASSING WEAK SHORTWAVE...WITH BETTER
FORCING FOR SHRA OR TSRA AFTER 18Z. WINDS WILL STAY SW TODAY WITH
LEE TROUGHING...BUT LIKELY TURN WNW THIS EVENING. SOME DRYING IS
INDICATED TONIGHT...BUT LINGERING BL MOISTURE COULD CREATE FOG/LOW
CLOUD PROBLEMS TOWARD DAYBREAK FRI.
ELSEWHERE...AN IFR STRATUS LAYER HAS DEVELOPED THIS MORNING AS MID
AND HIGH CLOUDS THINNED OUT OVERNIGHT. THIS SHOULD BURN OFF FAIRLY
QUICKLY...WITH MAINLY VFR CUMULUS FILLING IN WITH HEATING OF THE
MOIST BOUNDARY LAYER. WILL START OFF WITH VCSH AT KAVL AND KHKY
FIRST...AND THEN INTRODUCE VCTS FOR MAINLY THE AFTERNOON
HOURS...WITH THE MOVING WINDOW FROM WEST TO EAST. ANY FURTHER
RESTRICTIONS WOULD BE DUE TO CONVECTIVE SHOWERS AND THESE SHOULD BE
SCATTERED AT BEST. SW WINDS AHEAD OF THE LEE TROUGH TODAY WILL TURN
NW OVERNIGHT...EXCEPT FOR WINDS REMAINING NW AT KAVL THROUGH THE
PERIOD. PROFILES WILL DRY OUT FROM THE TOP DOWN TONIGHT...BUT
LINGERING BL MOISTURE COULD CREATE FOG/VSBY PROBLEMS OVERNIGHT. WILL
ONLY FEATURE IFR FOG AT KAVL...WITH MVFR FOG AT KHKY AND KAND...AS A
STARTING POINT.
OUTLOOK...BRIEF DRYING FROM THE WEST IS EXPECTED INTO FRIDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST ON SATURDAY AND
MOVE EAST OF THE AREA ON SUNDAY. DRY HIGH PRES WILL DOMINATE THE
AREA EARLY NEXT WEEK.
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...CSH
NEAR TERM...MCAVOY
SHORT TERM...JDL
LONG TERM...CSH
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1033 AM EDT THU SEP 6 2012
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL DRIFT ACROSS THE REGION TODAY FOLLOWED
BY SLIGHTLY DRIER AIR FOR FRIDAY. A STRONG COLD FRONT WILL MOVE
ACROSS THE AREA SATURDAY AND SATURDAY NIGHT WITH DRY AIR
OVERSPREADING THE REGION ON SUNDAY. DRY HIGH PRESSURE WILL SETTLE
OVER THE REGION EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EDT...THE LATEST RAP MATCHES WELL WITH THE WATER VAPOR
IMAGERY DEPICTION OF A SHORT WAVE ALONG THE NC/TN LINE. THIS FEATURE
WILL GRADUALLY MOVE EAST THROUGH THE DAY. THE NAM CURRENTLY HAS TOO
MUCH CONVECTION OVER THE WRN PART OF THE FA WITH THIS FEATURE AS
DOES THE RAP. THERE IS QUITE A BIT OF LOW CLOUD COVER ACROSS THE
FOOTHILLS AND PIEDMONT ATTM WHICH IS CUTTING OFF SFC HEATING. THIS
WILL RESULT IN CONTINUED SUPPRESSION OF CONVECTION INTO THE EARLY
AFTN. THEREAFTER...THE MODEL SOLUTIONS OF SCT CONVECTION DEVELOPING
OVER THE FOOTHILLS OR WESTERN PIEDMONT BY EARLY AFTN AND THEN
TRACKING EAST OF FA BY EARLY EVENING STILL LOOKS GOOD.
TO ACCOUNT FOR THESE TRENDS I/VE CUT BACK POPS THROUGH 17 UTC.
THEREAFTER I HAVE MUCH THE SAME WEATHER AND POP GRIDS THAT THE MID
SHIFT HAD.
AS OF 700 AM EDT...THE MID AND HIGH CLOUDS OVER THE REGION AHEAD OF
AN APPROACHING H5 SHORTWAVE HAVE THINNED A BIT...BUT THIS HAS
PERMITTED LOW STRATUS TO BECOME A BIT MORE WIDESPREAD...SO THERE IS
NO NET CHANGE IN THE SKY COVER. SHOWER COVERAGE IS SLOWLY RAMPING UP
OVER THE MTNS AS UPPER DPVA STARTS TO MOVE IN. THE MOST POTENT VORT
MAX IN THE UPSTREAM SHORTWAVE TROUGH SHOULD CROSS THE SRN
APPALACHIANS MAINLY THIS MORNING AND THEN MOVE OUT OVER THE PIEDMONT
THROUGH THE AFTN OR EARLY EVENING HOURS. WESTERLY DOWNSLOPING FLOW
AT LOW LEVELS MAY INITIALLY KEEP PRECIPITATION COVERAGE LOW EAST OF
THE MTNS THIS MORNING...BUT THE PASSING UPPER SUPPORT ALONG WITH
DEVELOPING LEE TROUGHING NEAR THE SURFACE SHOULD PROVIDE ENOUGH LIFT
FOR SCATTERED CONVECTION THIS AFTN. IN ADDITION TO THE
DOWNSLOPE...GRADUAL MID AND UPPER LEVEL DRYING IN THE SOUNDINGS
COULD LIMIT POPS SOMEWHAT. WILL THUS HEDGE TOWARD THE DRIER GFS
BASED MOS FOR POPS THIS AFTN. THE MID LEVEL DRYING...HOWEVER...COULD
INCREASE THE MICROBURST THREAT WITH ANY TSTMS THAT DO MANAGE TO
DEVELOP OVER THE PIEDMONT. IN ADDITION...MAX TEMPERATURES SHOULD BE
A COUPLE OF DEGREES WARMER THAN WED AFTN MOST AREAS. THIS WILL ADD
TO THE PIEDMONT INSTABILITY WHERE SFC DEWPOINTS SHOULD LINGER AROUND
70 DEGREES THROUGH LATE DAY.
STRONGER DRYING FROM THE TOP DOWN IS EXPECTED TONIGHT AS FLOW TURNS
NW TO N THROUGH A DEEP LAYER. THE BOUNDARY LAYER...HOWEVER...SHOULD
REMAIN FAIRLY MOIST TO CREATE THE POTENTIAL FOR FOG/VSBY PROBLEMS
OVERNIGHT. MIN TEMPS WILL LIKELY BE A CATEGORY COOLER THAN IN RECENT
DAYS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 245 AM THURSDAY...THE ATMOSPHERE IS PROGGED TO DRY OUT
CONSIDERABLY ON FRIDAY...WITH FORECAST SOUNDING PWATS DECREASING TO
AROUND ONE INCH BY AFTERNOON. MEANWHILE...A LOW AMPLITUDE UPPER
RIDGE AXIS WILL NOSE INTO THE REGION FROM THE SOUTHWEST. THESE
FACTORS WILL RESULT IN ONE OF THE LOWEST POP DAYS WE/VE SEEN IN SOME
TIME. NEVERTHELESS...STRONG INSOLATION (MAX TEMPS AROUND 90 EXPECTED
IN THE PIEDMONT) WILL ALLOW FOR MODERATE DESTABILIZATION...WHICH
SHOULD SUPPORT SOME HIGH TERRAIN CONVECTION BY LATE AFTERNOON.
FORECAST SOUNDINGS DEPICT A WEAK MID-LEVEL SUBSIDENCE INVERSION IN
THE PIEDMONT...SO IT IS UNCERTAIN AS TO HOW FAR INTO THE FOOTHILLS/
PIEDMONT THE ATMOSPHERE WILL BE ABLE TO SUSTAIN CONVECTION. SLIGHT
CHANCE POPS WERE INHERITED OUTSIDE THE MTNS...AND THIS STILL SEEMS
REASONABLE.
CONVECTION SHOULD DISSIPATE FATHER QUICKLY FRIDAY EVENING.
HOWEVER...STRONG HEIGHT FALLS WILL BE OCCURRING DURING THIS TIME
WEST THROUGH NORTHWEST OF THE AREA...DRIVING A STRONG COLD FRONT
TOWARD THE APPALACHIANS FRIDAY NIGHT. THERE ARE SLIGHT TIMING
DIFFERENCES IN THE OPERATIONAL MODELS...WITH THE NAM BEING ABOUT 3
HOURS FASTER THAN THE GFS. WE HAVE FAVORED THE SLIGHTLY FASTER
NAM...AS THERE WILL PROBABLY BE A MAJOR CONVECTIVE/COLD POOL
COMPONENT TO THE FRONTAL BAND...WHICH ALWAYS SEEMS TO RESULT IN
FASTER TIMING THAN DEPICTED BY THE MODELS. SPEAKING OF WHICH...
SATURDAY COULD BE AN INTERESTING CONVECTIVE DAY FOR OUR AREA...AS
THE COLD FRONT SEEMS DESTINED TO SWEEP ACROSS THE PIEDMONT DURING
PEAK HEATING TIME. THERE MAY BE EXTENSIVE MORNING HIGH CLOUDS AND
MID-LEVEL LAPSE RATES WILL BE WEAK...WHICH WOULD LIKELY LIMIT CAPE
VALUES TO WELL UNDER 2000 J/KG. NEVERTHELESS...IT APPEARS SHEAR WILL
BE FAIRLY STRONG...PARTICULARLY IN THE LOWER LEVELS...SO THERE IS A
LOW-END ORGANIZED SEVERE WEATHER THREAT.
CHANCE POPS WILL BEGIN OVER THE SOUTHWEST NC MTNS LATE FRIDAY
NIGHT...INCREASING TO LIKELY ACROSS THE MTNS BY EARLY AFTERNOON...
WITH HIGH CHANCES EXTENDING TO THE EAST DURING MID/LATE AFTERNOON.
THE MODEL CONSENSUS IS TO SWEEP ALL CONVECTION EAST OF THE AREA BY
00Z SUNDAY...SO POPS HAVE BEEN ADJUSTED DOWN SAT NIGHT THROUGH EARLY
SUNDAY. (SLIGHT/LOW CHANCES AT 00Z...DIMINISHING TO LESS THAN 20
PERCENT BY 12Z). COOL ADVECTION FLOW WILL RESULT IN MIN TEMPS ABOUT
A CAT BELOW NORMAL SUNDAY MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 130 AM EDT THURSDAY...L/WV TROUGH AXIS WITH DRY AND COOLER
NORTHERLY LLVL FLOW IS PROGGED TO BE ATOP THE REGION ON MONDAY.
TEMPERATURES WILL START OFF THE PERIOD 2-3 CATEGORIES BELOW CLIMO.
SFC RIDGE AXIS WILL BUILD IN ON TUESDAY AS UPPER TROUGH AXIS
PROGRESSES OFFSHORE AND GIVES WAY TO NW FLOW ALOFT. CONTINUED DRY
CONDITIONS ARE EXPECTED WITH TEMPERATURES NEAR PERSISTENCE. DEEP
LAYERED RIDGING WILL THEN DEVELOP ACRS THE SE CONUS BY THE END OF THE
PERIOD AND MAX TEMPERATURES ON WEDNESDAY WILL MODERATE A FEW DEG F
BUT STILL AVERAGE BELOW NORMAL.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LOW CLOUD IR SATELLITE PRODUCT SHOWS IFR CIGS KNOCKING
ON THE DOOR AT CLT. WILL NEED TO CARRY TEMPO IFR FOR AT LEAST AN
HOUR. THERE IS NOT TOO MUCH MID OR HIGH CLOUD AT PRESENT ABOVE THE
PIEDMONT STRATUS LAYER...SO IT SHOULD BURN OFF FAIRLY QUICKLY.
ATTENTION WILL THEN TURN TO THE PASSING WEAK SHORTWAVE...WITH BETTER
FORCING FOR SHRA OR TSRA AFTER 18Z. WINDS WILL STAY SW TODAY WITH
LEE TROUGHING...BUT LIKELY TURN WNW THIS EVENING. SOME DRYING IS
INDICATED TONIGHT...BUT LINGERING BL MOISTURE COULD CREATE FOG/LOW
CLOUD PROBLEMS TOWARD DAYBREAK FRI.
ELSEWHERE...AN IFR STRATUS LAYER HAS DEVELOPED THIS MORNING AS MID
AND HIGH CLOUDS THINNED OUT OVERNIGHT. THIS SHOULD BURN OFF FAIRLY
QUICKLY...WITH MAINLY VFR CUMULUS FILLING IN WITH HEATING OF THE
MOIST BOUNDARY LAYER. WILL START OFF WITH VCSH AT KAVL AND KHKY
FIRST...AND THEN INTRODUCE VCTS FOR MAINLY THE AFTERNOON
HOURS...WITH THE MOVING WINDOW FROM WEST TO EAST. ANY FURTHER
RESTRICTIONS WOULD BE DUE TO CONVECTIVE SHOWERS AND THESE SHOULD BE
SCATTERED AT BEST. SW WINDS AHEAD OF THE LEE TROUGH TODAY WILL TURN
NW OVERNIGHT...EXCEPT FOR WINDS REMAINING NW AT KAVL THROUGH THE
PERIOD. PROFILES WILL DRY OUT FROM THE TOP DOWN TONIGHT...BUT
LINGERING BL MOISTURE COULD CREATE FOG/VSBY PROBLEMS OVERNIGHT. WILL
ONLY FEATURE IFR FOG AT KAVL...WITH MVFR FOG AT KHKY AND KAND...AS A
STARTING POINT.
OUTLOOK...BRIEF DRYING FROM THE WEST IS EXPECTED INTO FRIDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST ON SATURDAY AND
MOVE EAST OF THE AREA ON SUNDAY. DRY HIGH PRES WILL DOMINATE THE
AREA EARLY NEXT WEEK.
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...CSH
NEAR TERM...MCAVOY
SHORT TERM...JDL
LONG TERM...CSH
AVIATION...HG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 PM CDT WED SEP 5 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
329 PM CDT WED SEP 5 2012
FOCUS THIS FORECAST PERIOD WAS ON THE NEXT WEATHER SYSTEM COMING
INTO THE AREA THURSDAY NIGHT AND FRIDAY. CHANCES ARE INCREASING
FOR A SHOWER PRODUCER.
CURRENT FRONTAL POSITION TOUGH TO DISCERN RIGHT NOW...BUT MAYBE
THE MORE IMPORTANT ELEMENT IS WHERE THE CONVERGENCE AND
INSTABILITY IS. SURFACE MOISTURE CONVERGENCE CURRENTLY LIES ACROSS
THE SOUTHERNMOST FORECAST AREA PER SPC 19Z ANALYSIS. MLCAPE IS UP
TO 1500 J/KG THERE WITH CIN ABOUT 50 J/KG. THERE IS SOME WEAKER
CONVERGENCE ACROSS NERN IA ALONG ANOTHER WEAK WIND SHIFT FROM WEST
TO N-NW.
THE NEXT FEW HOURS HOLD A CHANCE FOR ISOLATED TSRA ACROSS NERN IA
AND SWRN WI BUT THIS CHANCE SHOULD SHIFT SOUTHEAST BY EVENING.
CURRENTLY DO NOT HAVE A TSRA CHANCE IN THE FORECAST THIS AFTERNOON
OR EVENING.
12Z 250 MB RAOB INFORMATION SHOWING A NICE HEIGHT FALL/RISE/FALL
SIGNAL OVERHEAD AND UPSTREAM INTO WRN ALBERTA...WITH THE
WESTERNMOST FALL OF OVER 100M/12HR ASSOCIATED WITH THE FRIDAY
SHORTWAVE TROUGH SHIFTING SOUTHEAST. A NICE WARM POOL OF AIR SEEN
WITH THAT SHORTWAVE TROUGH OVER ALBERTA/BRITISH COLUMBIA THERE
TOO..AND 100KT JET CORE...WITH LATEST RUC ANALYSIS SHOWING THE
TROPOPAUSE FOLD DOWN TO 500MB OVER CENTRAL BC. SHORTWAVE RIDGE TO
BUILD IN FOR TONIGHT/THURSDAY IS CENTERED NEAR KGGW WITH 80M/12HR
HEIGHT RISES AT 250 MB.
RIDGE BUILDING WILL CONTINUE OVERNIGHT WITH ENOUGH 0-2KM AGL FLOW
/GREATER THAN 10KTS/ TO KEEP MISSISSIPPI RIVER VALLEY FOG OUT OF
THE PICTURE. HOWEVER...HAVE KEPT THE WI RIVER VALLEY FOG IN FOR
THU MORNING AS MORE ORTHOGONAL NW FLOW WILL ALLOW FOR DECOUPLING
IN THE BOUNDARY LAYER. PLUS...DEWPOINTS WILL BE HIGHEST IN THAT
AREA OVERNIGHT...HAVE SLOWED THE DRIER AIR ADVECTION.
ALBERTA/BC SHORTWAVE TROUGH TO BRING FALL-LIKE DYNAMICS TO THE AREA
THURSDAY NIGHT AND INTO FRIDAY. PRETTY GOOD CONSISTENCY IN THE
LARGER SCALE FORCING PRESENTED IN THE 05.12Z NAM/GFS THIS MORNING
AND BECAUSE OF THIS...HAVE RAISED RAIN CHANCES LATE THURSDAY NIGHT
INTO FRIDAY. THE SHORTWAVE ROUGH ENERGY SPLITS AS IT HEADS
SOUTHEAST WITH A PORTION MOVING IN FROM THE DAKOTAS AND THE SECOND
COMING IN FROM THE SOUTHWEST. THESE EACH HAVE A SMALL JET CORE
ASSOCIATED WITH THEM AND BY LATER THU NIGHT-FRIDAY...IT APPEARS THEY
INTERACT IN A COUPLED JET SCENARIO OVER THE AREA FOR GOOD DIVERGENCE
ALOFT. A STRONG BAROCLINIC ZONE IN THE 700-850MB LAYER WITH THE
INITIAL SHORTWAVE TROUGH WILL ALSO CREATE A W-E RAIN BAND WITH ITS
FORCING IN FRONTOGENESIS FROM CENTRAL MN-NRN WI...WHICH SLOWLY
SHIFTS INTO THE NWRN FORECAST AREA BY FRIDAY MORNING. THIS IS
SOMEWHAT IN CONCERT WITH 500-300MB QVECTOR CONVERGENCE.
MEANWHILE...BACK AT THE RANCH...THETA-E CONVERGENCE IN THE LOW-
LEVELS WILL ALSO START INCREASING IN THE WRN AND NRN FORECAST BY
12Z FRIDAY. THEN...QG FORCING INCREASES AS SECOND SHORTWAVE TROUGH
ENERGY PIECE SHIFTS ACROSS THE SOUTHERN FORECAST AREA. 05.12Z
ECMWF HAS THESE COMPONENTS...JUST FURTHER NORTH AND
SOUTH...SPLITTING AROUND THE FORECAST AREA.
05.09Z SREF DATA SUGGESTS ANY CAPE OVER 500 J/KG SHOULD REMAIN SOUTH
OF THE FORECAST AREA WITH DEWPOINTS STRUGGLING TO REACH MIDDLE 50S.
HOWEVER...WITH STEEPER LAPSE RATES IN THE MID-LEVELS AND STRONGER
FRONTOGENESIS...COULD SEE SOME THUNDER THU NIGHT UNTIL IT IS USED
UP.
OVERALL...THE SIGNALS ARE BEST IN THE NRN AND SRN FORECAST
AREA...BUT LARGE ENOUGH SIGNALS EXIST TO MOVE TOWARD A LIGHT RAIN
SHOWER SOLUTION FOR LATE THURSDAY NIGHT AND INTO FRIDAY. AMOUNTS MAY
NOT BE LARGE WITH LIMITED INSTABILITY IN THE FORECAST AREA...AROUND A
QUARTER OF AN INCH TOTAL. RAIN SHOULD CLEAR QUICKLY EAST LATER ON
FRIDAY. CURRENTLY THE FORECAST TEMPERATURES HAVE A 10F DIURNAL RANGE
FRIDAY...AND IF IT SHOWERS ALL DAY...IT WOULD LIKELY BE ABOUT 5F.
CONFIDENCE IS INCREASING ON THE RAIN EVENT...BUT NOT HIGH ENOUGH TO
CUT HIGHS FRIDAY MORE. THIS WILL BE NEEDED IF WE INCREASE THE RAIN
CHANCES MORE IN COMING FORECASTS.
NOTE...THE NCEP GFS MODEL WAS CHANGED TODAY AT 12Z TO TRY AND
SOLVE THE COLD/MOIST BIAS IN THE LOWEST 3KM AGL THAT HAS BEEN
EVIDENT SINCE LAST YEAR. IT APPEARED BETTER WITH ITS
INITIALIZATION IN THE LOW LEVELS.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
329 PM CDT WED SEP 5 2012
WITH NORTHWEST FLOW OVER THE AREA FOR THE WEEKEND...THERE IS SOME
SIGNAL FOR A SHORTWAVE TROUGH TO SHIFT THROUGH THE GREAT LAKES
SATURDAY NIGHT. AT THIS TIME THE 05.00Z ECMWF AND 05.12
GEM/GFS/ECMWF REMAIN CONSISTENT IN SHOWERS OVERNIGHT IN EASTERN
WISCONSIN. THERE IS A VERY DEEP TROPOSPHERIC QG FORCING SIGNAL
MOVING THROUGH EASTERN WI PER THE 05.12Z ECMWF. THUS...HAVE ADDED
SOME SMALL SHOWER CHANCES TO CENTRAL WI AREAS. IF THIS SIGNAL
CONTINUES...MORE CLOUD AND HIGHER RAIN CHANCES WILL BE NEEDED. IT
LOOKS LIKE A FAST MOVER TO LIMIT THE IMPACT ON THE WEEKEND
WEATHER.
RIDGE BUILDING THEN IN CONTROL OF WEATHER SUN-TUE WITH
TEMPERATURES WARMING. THERE ARE SOME SIGNALS THAT TUESDAY COULD BE
IN A PREFRONTAL SOUTHWESTERLY FLOW WITH 90F POSSIBLE. HAVE BUMPED
HIGHS ABOUT 3F AND THE ONLY THING HOLDING OFF THE FORECAST OF
WARMER HIGHS IS THE TIMING OF A STRONG FRONT AT DAY 6 CAN GET
TRICKY.
&&
.AVIATION...
1145 PM CDT WED SEP 5 2012
KLSE VALLEY FOG BECOMING MORE OF A CONCERN AS TDS HAVE RISEN IN THE
EVENING...AS EXPECTED...BUT HAVEN/T FALLEN OFF AS MUCH TO THE WEST.
SOME SIGNS THAT IT IS STARTING...AND THIS COULD GRADUALLY WORK INTO
KLSE DURING THE OVERNIGHT HOURS. THE T/TD SPREAD OF 4 F AT 03Z IS
FAVORABLE FOR DENSE FOG AT KLSE. ADD IN SKC...VRB/CALM WINDS...AND
MOIST GROUNDS FROM RECENT RAINS AND IT IS NEARLY AN IDEAL SETUP.
HOWEVER...THE DEPTH OF THE LIGHT WINDS IS NOT OVERLY DEEP...PER
BUFKIT SOUNDINGS. MORE IMPORTANTLY...AND PROBABLY WHAT WILL BE MAIN
FACTOR OF WHETHER OR NOT 1/4SM FG WILL FORM AT KLSE...IS HOW SOON
THAT DRY AIR WORKS IN. IF IT HANGS JUST WEST...DENSE FOG IS
PROBABLE. IF IT STARTS TO MOVE IN BY 09Z...P6SM SHOULD BE PREVALENT.
WILL HOLD WITH THE BCFG FOR NOW AS OBS ARE INDICATING THAT DRYING IS
STARTING TO PRESS IN.
THE HIGH WILL EXIT EAST THU NIGHT...ALLOWING FOR A COUPLE UPPER
LEVEL SHORTWAVE TROUGHS TO TAKE AIM ON THE UPPER MISSISSIPPI RIVER
VALLEY. FORCING/LIFT AND INCREASING SATURATION WILL RESULT IN CLOUDS
AND A CHANCE FOR SHRA. THE BETTER RAIN CHANCES SHOULD LIE
NORTH-SOUTH OF KRST/KLSE...WHERE THE SHORTWAVES ARE EXPECTED TO
TRAVERSE. BUT ENOUGH LIFT/MOISTURE FOR SOME SCT SHRA LATE THU NIGHT.
LITTLE IF ANY INSTABILITY...SO DON/T EXPECT A TS THREAT AT THIS
TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
329 PM CDT WED SEP 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BAUMGARDT
LONG TERM....BAUMGARDT
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS TUCSON AZ
945 PM MST FRI SEP 7 2012
.SYNOPSIS...ABUNDANT MOISTURE WILL RESULT IN MAINLY AFTERNOON AND
EVENING THUNDERSTORMS THROUGH WEDNESDAY. HEAVY RAINFALL WILL OCCUR
WITH THE STRONGER THUNDERSTORMS. THEREAFTER...A DRYING TREND IS
EXPECTED FOR THE LATTER PART OF NEXT WEEK.
&&
.DISCUSSION...NOT AS ACTIVE OF AN EVENING AS EARLIER THOUGHT. HAD
ISOLATED AREAS OF HEAVY RAIN LATE THIS AFTERNOON/EARLY THIS EVENING
EAST OF TUCSON. ATMOSPHERE STILL EXTREMELY MOIST FOR SEPTEMBER
ALTHOUGH PRECIPITABLE WATER VALUES ARE SLOWLY DECREASING. MADE SOME
ADJUSTMENTS TO THE FORECAST EARLIER THIS EVENING WHEN THE FLASH
FLOOD WATCH WAS CANCELLED. AT 9 PM...DOPPLER RADAR SHOWED A FEW
LIGHT SHOWERS ALONG GILA/GRAHAM COUNTY LINE WITH THE REST OF SE
ARIZONA PRECIPITATION FREE. TO OUR EAST...THERE WERE WIDESPREAD
SHOWERS AND THUNDERSTORMS MOVING ACROSS SOUTHERN NEW MEXICO IN
ADVANCE OF BACK DOOR COLD FRONT. THIS ACTIVITY EXTENDED ACROSS THE
INTERNATIONAL BORDER. THIS BACK DOOR COLD FRONT WILL CONTINUE TO
SLOWLY PUSH WEST WHILE AT THE MID-LEVELS THERE IS AN UPPER LOW OVER
NORTHERN SONORA. BASED ON LATEST HRRR MODEL...WHICH SEEMS TO PICK UP
THE ACTIVITY ACROSS SOUTHERN NEW MEXICO/FAR NORTHERN CHIHUAHUA
MEXICO NICELY...SHOWERS/ISOLD THUNDERSTORMS WILL PUSH INTO FAR
EASTERN ARIZONA AROUND MIDNIGHT AND THEN GRADUALLY PUSH WEST TOWARD
TUCSON THROUGH SUNRISE. LOCALIZED HEAVY RAINERS POSSIBLE WITH ANY
STORM OVERNIGHT BUT NOT WIDESPREAD ENOUGH TO WARRANT PUTTING OUT
ANOTHER FLASH FLOOD WATCH. I WILL MAKE SOME SIGNIFICANT ADJUSTMENTS
TO THE OVERNIGHT FORECAST...ESPECIALLY FOR AREAS EAST OF TUCSON.
&&
.AVIATION...SCTD SHRA/ISOLD TS OVERNIGHT EAST OF TUCSON. FROM TUCSON
WEST...SLGT CHANCE OF SHRA/TS. SCT -TSRA/-SHRA SATURDAY AFTERNOON.
OTHERWISE...VFR CONDITIONS AND SURFACE WIND MOSTLY LESS THAN 10 KTS
THRU SATURDAY EVENING OR 09/03Z. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED THUNDERSTORMS WILL OCCUR THIS WEEKEND INTO
EARLY NEXT WEEK FOLLOWED BY A GRADUAL DECREASE IN THUNDERSTORMS
THROUGH THE END OF NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GOODLAND KS
229 AM MDT SAT SEP 8 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 228 AM MDT SAT SEP 8 2012
03Z WATER VAPOR IMAGERY AND RUC 1.5 PVU SFC INDICATED SHORTWAVE
TROUGH MOVING INTO SOUTHERN KANSAS WITH LARGE AREA OF
DRYING/SUBSIDENCE OBSERVED OVER THE CWA. AT THE SFC...1024 MB SFC
HIGH WAS SETTLING OVER THE AREA WITH TDS IN THE UPPER 30S OBSERVED TO
THE NORTHWEST OF CWA.
MAIN SHORT TERM FORECAST CONCERNS WILL CENTER AROUND TEMPERATURES
AND POTENTIAL FIRE WX IMPACTS AS HIGH AMPLITUDE RIDGE WILL BE
DOMINANT WEATHER FEATURE ACROSS THE AREA THROUGH THE REST OF THE
WEEKEND.
TODAY-SUNDAY...STRONG SUBSIDENCE BEHIND DEPARTING SHORT WAVE TROUGH
WILL NOT ONLY CLEAR OUT CLOUDS ACROSS THE AREA BUT LEAVE IN ITS WAKE
A STABLE MID LEVEL TEMPERATURE PROFILE TODAY AS HIGH AMPLITUDE RIDGE
BEGINS TO BUILD OVER THE REGION. WITH SUCH A STABLE PROFILE...WINDS
ALOFT NOT INDICATING ANY SIGNIFICANT MOISTURE ADVECTION AND LITTLE
OF ANY LARGE SCALE FORCING FOR ASCENT...THINK CURRENT FORECAST OF
DRY CONDITIONS LOOKS REASONABLE AND DO NOT SEE NEED FOR ANY MAJOR
ADJUSTMENTS.
TEMPERATURES WILL BE SEVERAL DEGREES WARMER TODAY THAN YESTERDAY
WITH FULL SUN AND LIGHT WINDS ALLOWING FOR AMPLE SFC HEATING AND
EXPECT MOST OF THE CWA TO BE AT OR ABOVE 80 DEGREES. SUNDAY A BIT
TRICKIER AS STRONG MODEL AGREEMENT THAT BACKDOOR COLD FRONT WILL
MOVE INTO THE AREA DURING THE EARLY MORNING HOURS...FORCED BY SHORT
WAVE TROUGH MOVING THROUGH THE NORTHERN PLAINS. STILL EXPECT LOTS OF
SUNSHINE/FULL MIXING SO AM HESITANT TO COOL THINGS OFF TO MUCH...BUT
THINK BACKING OFF A FEW DEGREES ON HIGH TEMPS IS IN ORDER.
AFTERNOON HUMIDITIES WILL FALL INTO THE TEENS TODAY AND AGAIN
TOMORROW...INCREASING FIRE WX CONCERNS. WINDS FOR THE MOST PART WILL
BE LIGHT AND VARIABLE TODAY...WITH ONLY AREA WHERE A FEW STRONGER
GUSTS ARE EXPECTED IS AROUND MCK AS THEY ARE CLOSER TO STRONGER
HEIGHT GRADIENT. OVERALL CONDITIONS TOO MARGINAL FOR A FIRE
HIGHLIGHT. SUNDAY IS A BIT MORE COMPLICATED AS SFC TROUGH WILL
STRENGTHEN THROUGH THE DAY...WIT STRONGEST PRESSURE
GRADIENT/SUSTAINED WINDS EXPECTED ACROSS EASTERN COLORADO. MIXED
LAYER DEWPOINTS COMBINED WITH WEIGHTED MODEL DATA WOULD SUPPORT
AFTERNOON HUMIDITIES IN THE 12-15 PERCENT RANGE AS WELL. HOWEVER
COLD FRONT IN THE AREA POSSIBLE KEEPING TEMPS COOLER AND LARGE TD
SPREADS NOTED ON SREF PLUMES...CONFIDENCE NOT HIGH ENOUGH FOR A FIRE
WEATHER WATCH AT THIS POINT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 228 AM MDT SAT SEP 8 2012
SUNDAY NIGHT-MONDAY NIGHT...HIGH AMPLITUDE RIDGE WILL GRADUALLY
SHIFT EAST OVER THE AREA AND WEAKEN SOMEWHAT THROUGH THE PERIOD AS
STRONG TROUGH ADVANCES ACROSS THE NORTHWEST CONUS. MAIN IMPACT FOR
THE AREA WILL BE WARMING MAX AND MIN TEMPS THROUGH THE PERIOD. WITH
LITTLE IN THE WAY OF MOISTURE ADVECTION DO NOT ANTICIPATE ANY
MEANINGFUL PRECIP THREAT DESPITE STEEPENING LAPSE RATES AND SFC
TROUGH IN AREA. POTENTIAL FOR WIDESPREAD CRITICAL FIRE WX CONDITIONS
WILL EXIST ACROSS MUCH OF THE AREA ON MONDAY AS SFC TROUGH SHIFTS TO
THE EAST BRINGING GUSTY SOUTHERLY WINDS TO THE AREA. WITH THIS
PERIOD BEING IN THE 60-72 HOUR TIME RANGE...CONFIDENCE NOT HIGH
ENOUGH FOR A WATCH ISSUANCE BUT WILL HAVE TO MONITOR CLOSELY AS
MONDAY APPROACHES.
STARTING ON TUESDAY AND THROUGH THE EXTENDED PERIOD THE REGION WILL
BE UNDER THE INFLUENCE OF A DEEP SLOW MOVING TROUGH. AT THIS TIME
THE FIRST IN A SERIES OF IMPULSES MOVING THROUGH THE FLOW WILL COME
ACROSS THE REGION ON TUESDAY ALLOWING FOR A COLD FRONT TO MOVE INTO
THE CWA TUESDAY NIGHT INTO WEDNESDAY. BETWEEN THE FORCING ASSOC WITH
THE IMPULSE AND FRONT...COUPLED WITH LIMITED INSTABILITY...SHOULD
SET THE STAGE FOR TSRA/SHRA LATE TUE AFTERNOON/NIGHT AND INTO
WEDNESDAY BEHIND THE FRONT. PRECIP CHANCES REMAIN THEREAFTER BUT
MORE LIMITED IN COVERAGE AS ANOTHER IMPULSE MOVES ACROSS ON THURSDAY
BUT LACKING THE INSTABILITY AND FORCING COMPARED TO TUESDAY
NIGHT/WEDNESDAY. THE PARENT TROUGH AXIS IS PROGGED BY THE 00Z GFS
AND EC TO MOVE EAST OF THE CWA ON FRIDAY WITH RISING HEIGHTS OVER
THE CNTRL HIGH PLAINS WHICH SHOULD CUT OFF PRECIP OPPORTUNITIES AT
THAT POINT. HIGH TEMPERATURES ON TUESDAY WILL BE SLIGHTLY ABOVE
NORMAL AHEAD OF THE COLD FRONT BUT THEN DROP BELOW NORMAL THROUGH
THE REST OF THE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1100 PM MDT FRI SEP 7 2012
VFR THROUGH THE PERIOD AT KGLD AND KMCK. SFC HIGH TO MOVE OVER THE
TERMINALS THROUGH THE PERIOD. MAY SEE SOME FAIR WX CU AT KGLD
AROUND 18Z WITH NORTHWEST WINDS NEAR 10 KTS. BY 00Z ANY CLOUDS
SHOULD DISSIPATE WITH THE LOSS OF DAYTIME HEATING AND WINDS WILL
BECOME VRB05KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...05/JRM
AVIATION...007
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1101 PM MDT FRI SEP 7 2012
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 210 PM MDT FRI SEP 7 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW POSITIVELY TILTED TROUGH
OVER NORTHERN GREAT LAKES WITH AXIS EXTENDING SOUTHWEST ACROSS
CENTRAL NEBRASKA. LARGE SCALE SUBSIDE IS CURRENTLY BUILDING INTO
TRI-STATE AREA AS THIS TROUGH SHIFTS EAST. AT THE SURFACE HIGH
PRESSURE BUILDING INTO THE CWA FROM THE NORTHWEST.
ISOLATED LIGHT SHOWERS/SPRINKLES WILL REMAIN POSSIBLE ACROSS THE NW
THIS AFTERNOON ASSOCIATED WITH COLD POOL ALOFT AND STEEPENING LAPSE
RATES. WE ALSO HAVE SOME WEAK H85-H7 FRONTOGENESIS LINGERING JUST TO
THE NORTHWEST OF THE CWA...RESPONSIBLE FOR CURRENT SHOWER ACTIVITY
OUTSIDE OF CWA. DO NOT ANTICIPATE ANY PRECIP LINGERING PAST SUNSET
WHEN DIURNAL HEATING COMES TO AN END.
COOLER AIR MASS ALREADY IN PLACE AFTER FRONTAL PASSAGE LAST
NIGHT...WITH H85 TEMPS BASED ON THIS MORNINGS 12Z SOUNDING IN THE
12-14C RANGE. WITH CALM WINDS AND CLEARING SKIES I EXPECT OVERNIGHT
TEMPS TO DROP TO THE LOW TO MID 40S ACROSS THE AREA. IF WE WERE TO
SEE LOWER TD VALUES ADVECT INTO THE CWA...THEN WE COULD BREAK A FEW
LOW TEMPERATURE RECORDS TONIGHT...WITH VALUES IN THE UPPER 30S.
PREVIOUS GUIDANCE WAS BRINGING MUCH LOWER TD VALUES INTO THE AREA
TONIGHT. HOWEVER...BASED ON UPSTREAM TRENDS AND CURRENT GUIDANCE TD
VALUES SHOULD REMAIN 40F OR HIGHER...WHICH WILL LIMIT COOLING
POTENTIAL.
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 226 PM MDT FRI SEP 7 2012
SATURDAY THROUGH SUNDAY NIGHT WILL REMAIN DRY AS THE UPPER LEVEL
RIDGE CURRENTLY OVER THE SOUTHERN CONUS BUILDS NORTHWARD OVER THE
GREAT BASIN AND EXPANDS EAST INTO THE PLAINS. SUNDAY AFTERNOON AND
SUNDAY NIGHT THE RIDGE WILL FLATTEN OUT AS A SHORT WAVE TROUGH MOVES
ACROSS IT. THE SHORT WAVE TROUGH WILL MOVE INTO THE AREA SUNDAY
NIGHT. HOWEVER AM ONLY EXPECTING SOME CLOUDS TO DEVELOP WITH THE
TROUGH DUE TO THE SHALLOW MOIST LAYER TO WORK WITH BETWEEN 500-600MB.
TUESDAY THROUGH FRIDAY WILL HAVE CHANCES FOR PRECIPITATION ALMOST
EVERY DAY. TUESDAY AN UPPER LEVEL SHORT WAVE TROUGH AND ASSOCIATED
SURFACE TROUGH MOVE ACROSS THE AREA PROVIDING AN OPPORTUNITY FOR
SOME LOCATIONS TO RECEIVE RAINFALL. TUESDAY NIGHT INTO WEDNESDAY
ANOTHER UPPER LEVEL SHORT WAVE TROUGH FOLLOWS A COLD FRONT THROUGH
THE AREA...OFFERING A SHOT FOR MORE WIDE SPREAD RAINFALL. THE NEXT
BEST CHANCE FOR WIDE SPREAD RAINFALL COMES WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT AS AN UPPER LEVEL LONG WAVE TROUGH MOVES ACROSS THE PLAINS. THERE
MAY BE SOME LINGERING STORM ACTIVITY ON FRIDAY AS THE TROUGH DEPARTS
THE AREA. HIGH TEMPERATURES WILL BE WARMEST ON MONDAY AND TUESDAY AHEAD OF THE
COLD FRONT...ROUGHLY 10 DEGREES ABOVE NORMAL. FROM WEDNESDAY
THROUGH FRIDAY HIGH TEMPERATURES WILL BE ALMOST 10 DEGREES BELOW
NORMAL. LOW TEMPERATURES FOR THE PERIOD WILL BE NEAR NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1100 PM MDT FRI SEP 7 2012
VFR THROUGH THE PERIOD AT KGLD AND KMCK. SFC HIGH TO MOVE OVER THE
TERMINALS THROUGH THE PERIOD. MAY SEE SOME FAIR WX CU AT KGLD
AROUND 18Z WITH NORTHWEST WINDS NEAR 10 KTS. BY 00Z ANY CLOUDS
SHOULD DISSIPATE WITH THE LOSS OF DAYTIME HEATING AND WINDS WILL
BECOME VRB05KTS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...99
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
400 AM EDT SAT SEP 8 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE MID ATLANTIC FROM THE NORTHWEST
THIS MORNING AND CROSS THE AREA THIS AFTERNOON AND EVENING. STRONG
TO SEVERE THUNDERSTORMS ARE EXPECTED IN ADVANCE OF THIS FRONT.
COOLER AND MUCH DRIER AIR WILL MOVE IN SUNDAY AND REMAIN OVER THE
REGION THROUGH AT LEAST MID WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
REST OF THE OVERNIGHT...WAVE OF LOW CLOUDS HAVE SPREAD NORTH
ACROSS THE NRN VA I-95 CORRIDOR AND MD PIEDMONT AND EAST. THESE
CLOUDS WILL PERSIST THROUGH SUNRISE BEFORE MIXING OUT IN ADVANCE
OF THE COLD FRONT. SCATTERED THUNDERSTORMS ARE EXPECTED TO
CONTINUE DEVELOPING OVER THE BAY OFF SRN MD THROUGH DAYBREAK. RAP
GUIDANCE DISPLAYED ON THE SPC MESOANALYSIS PAGE DOES INDICATE 2000
J/KG OVER SRN MD PORTIONS OF THE BAY...SO ACTIVITY MAY BE VIGOROUS
DESPITE THE EARLY MORNING HOUR.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM SUNDAY/...
TODAY...07Z REGIONAL RADAR MOSAIC DEPICTS GRADUAL WEAKENING OF
PRECIP SHIELD IN ADVANCE OF A COLD FRONT STRETCHING FROM THE ERN
GREAT LAKES THROUGH THE MID SOUTH STATES. THIS PREFRONTAL ACTIVITY
WILL APPROACH FROM THE WEST THROUGH MID MORNING. 04Z HRRR PROPERLY
DEPICTS CURRENT ACTIVITY AND TREND...WITH LEADING PRECIP REACHING
THE ALLEGHENY FRONT AROUND 14Z...WITH MORE OF A SCATTERED LINE OF
PRECIP DEVELOPING OVER THE POTOMAC HIGHLANDS LATE IN THE MORNING.
POPS WERE UPDATED WITH A HEAVY LEANING TOWARD SREF. POPS THEN
DECREASED FOR THE PIEDMONT AND WEST DUE TO LOCAL WRF ARW RUNS AND
00Z SPC 4KM NMM RUN DEPICTING A BIT OF A DC SPLIT THAT COAGULATES
JUST EAST OF DC /AS IS OFTEN SEEN...PARTICULARLY WITH LATE AFTERNOON
AND EVENING TIMING/. TALL SKINNY CAPE OF ONLY UP TO 2000 J/KG /AN
18Z RAOB WAS REQUESTED BY SPC/. BULK SHEAR IN EXCESS OF 30 KT COULD
ALLOW SOME DISCRETE SUPERCELL DEVELOPMENT. DAMAGING WINDS MAIN
THREAT. AN ISOLATED TORNADO CANNOT BE RULED OUT...THOUGH BEST
SHEAR/CAPE CONVERGENCE FOR THOSE ARE FARTHER NORTH. MOTION SHOULD BE
QUICK ENOUGH TO LIMIT FLASH FLOODING THREAT DESPITE HEAVY RAIN.
MAX TEMPS MID 80S EAST OF THE BLUE RIDGE /UPR 70S TO LOW 80S WEST
DEPENDING ON PRECIP AND CLOUDS/.
TONIGHT...TRAILING STRATIFORM EXPECTED TO MOVE EAST THROUGH THE
EVENING...WITH DRY/COOL AIR COMING IN FROM THE NW. NWLY FLOW AROUND
10 MPH WILL LIMIT FOG. MIN TEMPS IN THE 40S IN THE POTOMAC
HIGHLANDS...50S ELSEWHERE /LOW 60S NEAR SHORE AND URBAN AREAS/ WITH
SKIES CLEARING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
COLD FRONT WILL BE OFFSHORE BY SUNDAY WITH COOLER AND DRIER HIGH
PRESSURE MOVING IN. TEMPS SHOULD STAY NEAR OR A LITTLE BELOW NORMAL
THROUGH AT LEAST MIDWEEK BEFORE TEMPS RISE A LITTLE AS THE HIGH
SHIFTS OFFSHORE AND WINDS SWAP TO A SOUTHERLY DIRECTION. THE NEXT
SIGNIFICANT WEATHER FEATURE IS A WEAK COLD FRONT APPROACHING BY THE
END OF NEXT WEEK. NO EXPECTED TROPICAL THREATS TO OUR FORECAST AREA
THROUGH NEXT WEEK.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
IFR/MVFR DECK MOVING NW ACROSS BALT-WASH METRO EARLY THIS
MORNING...ISOLATED SHOWERS/THUNDERSTORMS EXPECTED WELL SOUTHEAST OF
DC THROUGH MID MORNING. SOUTHERLY FLOW WILL CONTINUE TO HOLD OFF IFR
MIST/FOG DEVELOPMENT.
SLY FLOW INCREASES THIS MORNING IN ADVANCE OF THE APPROACHING COLD
FRONT. LINE/S/ OF THUNDERSTORMS EXPECTED IN ADVANCE OF THE FRONT
ACROSS THE TERMINALS FROM WEST TO EAST THIS AFTERNOON INTO THE
EVENING. SOME STORMS MAY BE STRONG/SEVERE...WITH DAMAGING WIND GUSTS.
PCPN ENDS AND CLOUDS GRADUALLY CLR TONIGHT WITH DRY NWLY FLOW AROUND
10 KT LIMITING FOG DEVELOPMENT.
VFR CONDS EXPECTED THRU NEXT WK. NW WINDS 10-20 KTS SUN/MON...
DIMINISHING THEREAFTER AS HIGH PRESSURE MOVES IN.
&&
.MARINE...
LULL IN SLY SCA THROUGH SUNRISE...THEN SCA LEVELS RETURN IN GUSTY
SLY FLOW AHEAD OF A COLD FRONT. LINE/S/ OF TSTMS EXPECTED LATE
AFTERNOON INTO EVENING ACROSS THE WATERS IN ADVANCE OF THE COLD
FRONT. SPECIAL MARINE WARNINGS EXPECTED SINCE MAIN THREAT WITH THE
WEATHER IS DAMAGING WINDS. NWLY FLOW AFTER THE FRONT CONTINUES SCA
FOR MAIN PORTIONS OF THE WATERS TONIGHT WITH GUSTS AROUND 20 KT.
GUSTY NW WINDS SUNDAY ARE EXPECTED TO REMAIN AROUND 20KTS FOR MUCH
OF THE BAY CHANNEL SOUTH OF BALTIMORE AND LOWER POTOMAC DURING THE
MORNING...REQUIRING A SMALL CRAFT ADVISORY THERE SUNDAY MORNING.
OTHERWISE NO MARINE HAZARDS THROUGH NEXT WEEK.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES EXPECTED TO REMAIN ABOUT THREE QUARTERS FOOT
ABOVE ASTRONOMICAL PREDICTION INTO SATURDAY EVENING WITH SLY FLOW
IN ADVANCE OF A COLD FRONT. POST FRONT WILL BE NWLY FLOW AND MORE
NORMAL WATER LEVELS. WITH THE PREFERRED TIDE TONIGHT HAVING
PAST...NO COASTAL FLOODING IS EXPECTED.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ531-539>541.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT
SUNDAY FOR ANZ530-538-542.
SMALL CRAFT ADVISORY UNTIL 3 PM EDT SUNDAY FOR ANZ532>534-537-
543.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 PM EDT THIS
EVENING FOR ANZ535-536.
&&
$$
SYNOPSIS...BAJ/CAS
NEAR TERM...BAJ
SHORT TERM...BAJ
LONG TERM...CAS
AVIATION...BAJ/CAS
MARINE...BAJ/CAS
TIDES/COASTAL FLOODING...BAJ
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
252 AM EDT SAT SEP 8 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE MID ATLANTIC REGION TODAY...AND
CROSS THIS AFTERNOON AND EVENING. STRONG THUNDERSTORMS ARE
EXPECTED AHEAD OF THIS FRONT. HIGH PRESSURE WILL BUILD BEHIND THE
COLD FRONT LATE TONIGHT THROUGH EARLY NEXT WEEK AND THEN DOMINATE
THROUGH THE REMAINDER OF THE WORK WEEK WITH DRY AND SEASONABLE
TEMPERATURES.
&&
.NEAR TERM /REST OF THE OVERNIGHT/...
WAVE OF LOW CLOUDS HAVE SPREAD NORTHWEST ACROSS THE I-95 CORRIDOR
AND EAST OVER THE PAST COUPLE HOURS. MAIN EFFECT FOR THE PUBLIC IS
WARMER CONDITIONS...WITH TEMPS PERSISTING IN THE LOW 70S WHERE
CLOUDS PERSIST. ISOLATED SHOWERS ARE EXPECTED TO DEVELOP SOUTHEAST
OF DC OVER THE NEXT COUPLE HOURS...PERHAPS SOME THUNDER BY
DAYBREAK OVER THE MD PORTION OF THE BAY. RAP GUIDANCE DISPLAYED ON
THE SPC MESOANALYSIS PAGE DOES INDICATE 2000 J/KG OVER SRN
MD PORTIONS OF THE BAY...SO ACTIVITY MAY BE VIGOROUS DESPITE THE
EARLY MORNING HOUR.
OTHERWISE...PREFRONTAL ACTIVITY WILL APPROACH FROM THE WEST
THROUGH SUNRISE. 03Z HRRR DEPICTS LEADING PRECIP REACHING THE
ALLEGHENY FRONT BY 13Z...WITH MORE OF A SCATTERED LINE OF PRECIP
DEVELOPING LATE IN THE MORNING. POPS WERE UPDATED WITH A HEAVY
LEANING TOWARD SREF /WITH POPS DECREASED A BIT/. EXPECT HEAVY
THUNDERSTORMS WITH DAMAGING WINDS AS THE MAIN THREAT AS WRITTEN IN
THE HWOLWX. WILL CONTINUE TO MONITOR LATEST GUIDANCE AND UPDATE
GRIDS AS NECESSARY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/...
CONFIDENCE IN SEVERE WEATHER INCREASING FOR THE DAYTIME HOURS
SATURDAY. DEEP UPPER TROUGH OVER THE WESTERN OHIO RIVER VALLEY
WILL PIVOT TOWARDS THE REGION...WHILE A STRONG SURFACE COLD FRONT
APPROACHES FROM THE WEST IN THE MORNING AND CROSS THE CWA DURING
THE DAY. STRONG UPPER LEVEL JET WILL SUPPORT A FAVORABLE SHEAR
ENVIRONMENT.
THERE ARE SOME QUESTIONS ABOUT AVAILABLE INSTABILITY DEPENDING
ON CLOUD COVER...BUT THIS IS EXPECTED TO BE MORE THAN COMPENSATED
FOR BY STRONG FORCING FROM THE FRONT. SPC HAS PLACED A FEW
COUNTIES IN NORTHEASTERN MARYLAND IN A MODERATE RISK...WHILE THE
REST OF THE CWA REMAINS IN A SLIGHT RISK. WITH STRONG WIND FIELDS
IN PLACE...MAIN THREAT WILL BE DAMAGING WINDS...WITH POTENTIAL FOR
SQUALL LINE DEVELOPMENT. THERE IS ALSO SOME TORNADO RISK...AS 12Z
MODEL FORECAST SOUNDINGS INDICATE HELICITY COULD EXCEED 200 M2/S2
BEFORE FRONTAL PASSAGE. HIGH TEMPS RANGE FROM THE UPPER 70S OVER
THE POTOMAC HIGHLANDS TO THE UPPER 80S OVER EASTERN PORTIONS OF
THE CWA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CDFNT SHUD BE CLEARING BAY BY 0Z...WITH PCPN RAPIDLY ENDING BEHIND
IT. SKIES SHUD CLR AFTER MIDNIGHT...THO UPSLOPE CLOUDS/SCT SHWRS
CUD PERSIST W OF ALLEGHENY FRONT IN NW FLOW. ULVL TROF WILL LAG A
BIT BEHIND FRONT AND ITS AXIS WILL NOT CROSS CWA UNTIL SUN EVE.
LLVLS WILL BE SCOURED OF ANY MOISTURE...BUT WITH STRONG
CAA...ESPECIALLY ALOFT...DIURNALLY STEEP LAPSE RATES AND ARRIVAL
OF ULVL VORT MAX SUN AFTN CUD INDUCE CU FIELD AND PERHAPS ISOLATED
SHWRS.
FOR NW...KEPT FCST DRY XCPT FOR UPSLOPE-FAVORED AREAS. AFTER ULVL
TROF MOVES PASSED...HIPRES AT ALL LVLS BUILDS IN MON AND RESIDES
NEARLY OVHD INTO LATE WEEK. THIS WILL MEAN DRY/NEARLY CLOUD-FREE
CONDS MON THRU AT LEAST THU. TEMPS WILL BE AUTUMN- LIKE...BELOW
AVG FOR MID-SEP. MAXIMA WILL BE GENERALLY IN 70S...XCPT 60S IN
MOUNTAINS. MINIMA WILL BE IN 50S E OF BLUE RIDGE...WITH 40S W.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
IFR/MVFR DECK MOVING NW ACROSS BALT-WASH METRO EARLY THIS
MORNING...ISOLATED SHOWERS/THUNDERSTORMS EXPECTED SOUTHEAST OF DC
THROUGH SUNRISE. SOUTHERLY FLOW HAS HELD OFF FOG DEVELOPMENT.
SUB VFR CONDITIONS LIKELY ON SATURDAY AS A STRONG COLD FRONT MOVES
THROUGH. NUMEROUS SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE
BOUNDARY. SOME STORMS MAY BE STRONG/SEVERE...WITH DAMAGING WIND
GUSTS.
PCPN ENDS AND CLOUDS GRADUALLY CLR SAT NGT...WITH VFR CONDS XPCD
THRU MUCH OF NEXT WK. NW WINDS 10-20 KTS SUN/MON...DIMINISHING
THEREAFTER AS HIPRES BUILDS IN.
&&
.MARINE...
LULL IN SLY SCA THROUGH SUNRISE...SCA LEVELS RETURN AFTER SUNRISE
WITH SLY FLOW INCREASING AHEAD OF A COLD FRONT. LINE/S/ OF TSTMS
EXPECTED LATE AFTERNOON INTO EVENING IN ADVANCE OF THE COLD FRONT.
SPECIAL MARINE WARNINGS EXPECTED SINCE MAIN THREAT WITH THE
WEATHER IS DAMAGING WINDS.
SCA XTDD SAT NGT FOR ALL ZONES...AS GUSTY SLY WINDS WILL QUICKLY
TRANSITION TO NLY AS CDFNT MOVES THRU. MAY BE A BRIEF PERIOD OF
SUB-ADZY THRESHOLD WINDS IN ASSOCIATION WITH FROPA...BUT OTHERWISE
20-25 KT GUSTS SEEM LIKELY. GUSTY NW WINDS SUN WILL LIKELY REQUIRE
ADDITIONAL ADZYS...AND THIS CUD CONT INTO MON.
&&
.TIDES/COASTAL FLOODING...
COASTAL FLOOD ADVISORY CANCELLED EARLY WITH LOWER THAN EXPECTED
LEVELS AND CRESTS OCCURRED. TIDAL ANOMALIES EXPECTED TO REMAIN
ABOUT THREE QUARTERS FOOT ABOVE ASTRONOMICAL PREDICTION INTO
SATURDAY EVENING WITH SLY FLOW IN ADVANCE OF A COLD FRONT. POST
FRONT WILL BE NWLY FLOW AND MORE NORMAL WATER LEVELS. WITH THE
PREFERRED TIDE TONIGHT HAVING PAST...NO COASTAL FLOODING IS
EXPECTED.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ531>534-537-
539>541-543.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EDT
SUNDAY FOR ANZ530-538-542.
SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 PM EDT THIS
EVENING FOR ANZ535-536.
&&
$$
UPDATE...JACKSON
AREA FORECAST DISCUSSION...CORRECTED.
NWS TALLAHASSEE FL
922 AM EDT Sat Sep 8 2012
Corrected to add Header.
.NEAR TERM [Through Tonight]...Just made some minor tweaks to the
fcst today, as what`s left of the Low Pressure Area in the northern
Gulf of Mexico is getting picked up by the Upper Trof and will move
onshore over the FL Panhandle today. This Low, which will continue
on its NE trek through the CWA is expected to bring likely to
categorical PoPs to the to the Tri-State area, so blended the
previous fcst PoPs with our locally derived CAM PoPs. It should also
be noted that PWATs have returned to the 2"+ level both from morning
soundings and Satellite estimates (which show them increasing
throughout the day from the SW as the Tropical moisture is pulled
back to the NE). The 08 UTC HRRR Hi-Res Model appears to have
initialized better than the WRF suite, so weighed that in when
raising PoPs a bit for this aftn. Did knock down Max Temps and
hourly temps 2-3 degrees as well, as the rain and increased cloud
cover is making rapid inroads inland already. Over the Coastal
Waters, the fcst is on track as Cautionary Conditions are already
underway, with winds and seas expected to increase just a bit out of
the SW this aftn.
&&
.Previous Discussion...
.SHORT TERM [Sunday Through Monday]...
The low over the Gulf of Mexico will lift northeastward into the FL
Panhandle today before being absorbed by the approaching cold front.
The front is forecast to reach our northwestern zones late this
afternoon and TLH around midnight before exiting southeast of the
area Sunday morning. The front will have slowed down quite a bit by
this time and may stall south of the area later on Sunday. All
guidance is pointing at a wet day today across the forecast area
today and we have maintained a high PoP forecast in the likely to
categorical range. Bulk shear is now forecast to be on the order of
20-25 knots just ahead of the front and severe weather is looking
less likely. That said, a few strong to severe storms will remain
possible. However, the primary threat will be locally heavy
rainfall. Rain chances will taper off from northwest to southeast
tonight and Sunday, but will not clear entirely out of Dixie County
until Monday morning (see table below). This will be the first
bonafide cold frontal passage of the fall season. As is typical of
these early season frontal passages, max temperatures behind the
front will not drop off all that much. However, humidity levels will
dip noticeably with dew points dropping into the upper 50s to lower
60s. Similarly, min temps will fall well into the 60s Sunday night,
with a few upper 50s possible over Southeast AL and adjacent
portions of the FL Panhandle.
&&
.LONG TERM [Monday Night through Friday]...
The extended period begins with a trough over wrn states, ridge
building E/SE to ern seaboard and trough over extreme wrn Atlc. At
surface, 1025mb high over OH/PA with strong ridge builds SWD across
Nrn Gulf. This continues NLY winds, drier air and lower humidities
advecting with somewhat tighter gradients into the local region. As
the high translates to the Mid-Atlantic states thru mid week, winds
will gradually veer to the east advecting moisture in from the
Atlantic. The surface high will slowly move east off the eastern
seaboard by the end of the week with the easterly flow continuing.
This will also begin to generate ELY surges at night especially
across the marine area. Forecast time height cross sections show
most moisture confined below 850mb with subsidence drying above as
upper ridging builds over the region thru 12Z Fri then progressively
increasing moisture. The week looks like a welcome break from the
very wet pattern that we`ve experienced this summer. The next chance
for more than isold shwrs will be on Friday and especially on
Saturday afternoons when the next upstream trough begins to suppress
deep layer ern ridge allowing for a modest increase in moisture.
Inverted surface trough also develops to our west.
Will go with NIL pops except wdly sct Fri aftn and Low sct Sat aftn.
Under NLY flow and near cloudless skies, Min temps commence 3 to 5
degrees below normal rising to near climo by Fri night. Max temps
will remain near climo. Avg inland min/max temps are 67 and 88
degrees.
&&
.AVIATION [Beginning 12Z Saturday]...
[through 12Z Sunday] Expect low stratus/CIGS to develop near the
Gulf coast as moist onshore flow continues, and filling in gradually
over S AL/S GA for the next few hours after sunrise. Will go with
reductions into MVFR range (with brief IFR at VLD). Should be high
coverage today into tonight for SHRA and even -TS in the morning at
ECP then late morning to TLH spreading to all Terminals in aftn.
Expect MVFR VSBYS/CIGS with -TSRA or VCTS 00z-06z especially VLD and
to a lesser extent TLH/ABY. After 06z, MVFR fog developing mainly at
VLD and to a lesser extent TLH with IFR likely at VLD near sunrise.
&&
.MARINE...
Winds have increased to cautionary levels over the local marine area
as low pressure just southeast of the Mississippi Delta lifts
northeast toward the Florida Panhandle. This low will reach the
Panhandle later today before being absorbed by a cold front. The
front will cross the waters from northwest to southeast tonight into
Sunday shifting winds to offshore. The front will then stall south
of the area early next week as high pressure builds into the Mid
Atlantic and Northeast. The gradient between the two systems will
increase across the eastern Gulf of Mexico. This will result in a
return of cautionary level winds to the forecast area from Tuesday
into Wednesday.
&&
.FIRE WEATHER...
A cold front will move across the local area thru Sunday spreading
ample showers, thunderstorms and gusty winds. In its wake, noticeably
drier air will overspread the region from north to south. Minimum RH
on Sunday afternoon will drop to the mid 30s across the inland FL
Panhandle but should remain above critical levels. Red flag
conditions are not expected during the upcoming work week.
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Wool
LONG TERM...Block
AVIATION...Block/Gould
MARINE...Block
FIRE WEATHER...Block
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EDT SAT SEP 8 2012
.DISCUSSION...
LATEST RAP ANALYSIS SHOWS RELATIVELY DRY AIR ADVECTING INTO THE SRN
HALF OF THE PENINSULA...H100-H70 AND H85-H50 MEAN RH BTWN 60-70PCT.
THIS IS REFLECTED IN THE MORNING SOUNDINGS WITH PWAT VALUES ARND
2.0" AT KJAX/KXMR...DECREASING TO ARND 1.8" AT KTBW/KMFL. H85-H50
LAPSE RATES ARE UNREMARKABLE WITH READINGS ARND 5.5C/KM...UPSTREAM
MID LVL VORTICITY VALUES ARE QUITE LOW...AND THE H30-H20 LYR IS
WEAKLY DIVERGENT AT BEST.
WITH SUCH WEAK DYNAMIC SUPPORT IN PLACE...MESOSCALE BNDRY COLLISIONS
WILL BE NECESSARY TO SPARK AFTN SHRAS/TSRAS ACRS THE CWA. HOWEVER...
EVEN THESE MAY BE HARD TO COME BY AS THE ATLC RIDGE AXIS OVER THE FL
STRAITS WILL REMAIN IN PLACE DUE TO A FRONTAL TROF BUILDING ACRS THE
APPALACHIAN. W/SW FLOW BTWN 10-15KTS THRU THE H100-H70 LYR ACRS THE
CENTRAL PENINSULA WILL DELAY THE FORMATION OF THE EAST COAST SEA
BREEZE UNTIL MID TO LATE AFTN AND MAY SUPPRESS IT ALTOGETHER N OF
SEBASTIAN INLET.
GIVEN THE DVLPG WX PATTERN...STORM COVERAGE THIS AFTN WILL BE LOWER
THAN IN RECENT DAYS. WILL LOWER POPS BY 10PCT ACRS THE BOARD.
REMAINDER OF THE FCST LOOKS GOOD. WARM SW FLOW WILL PUSH DAYTIME
HIGHS INTO THE L90S OVER MOST OF THE CWA...U80S ALONG THE IMMEDIATE
COAST.
BEACHGOERS WILL NEED TO BE ALERT FOR A HIGH RIP CURRENT RISK AND
ROUGH SURF CONDITIONS GIVEN A BUILDING LONGER PERIOD SWELL OF
12-14 SECONDS MOVING INTO THE LOCAL WATERS.
&&
.AVIATION...
THRU 08/17Z...PREVAILING VFR ALL SITES...SLGT CHC IFR TSRAS N OF
KISM-KDAB. BTWN 08/17Z-08/20Z...SFC WNDSHFT FM SW TO S/SE AOB 12KTS
S OF KVRB ASSOCD WITH THE EAST COAST SEA BREEZE. BTWN
08/17Z-09/01Z...SCT IFR/ISOLD LIFR TSRAS AREAWIDE...MORE NMRS N OF
KISM-KTIX AS MID LVL DRY AIR ADVECTION OCCURS OVR THE S HALF OF
FL...STORM MOTION E/NE 10-15KTS. AFT 09/01Z...VFR ALL SITES.
&&
.MARINE...
NO SIG CHANGES. RIDGE AXIS OVER THE FL STRAITS WILL GENERATE A
GENTLE TO MODERATE SWRLY BREEZE ACRS THE LCL ATLC. LONG PD SWELLS
FROM DISTANT T.C. LESLIE WILL KEEP SEAS IN THE 3-4FT RANGE
NEARSHORE...4-5FT RANGE OFFSHORE. SWELL PDS BTWN 12-14SEC WILL
GENERATE HAZARDOUS CONDITIONS AT THE INLETS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
RADAR/IMPACT WX.......LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
950 AM EDT SAT SEP 8 2012
.DISCUSSION...
SURFACE HIGH PRESSURE REMAINS ACROSS THE SOUTHERN PENINSULA THIS
MORNING WHILE A COLD FRONT IS MOVING INTO THE SOUTHEASTERN STATES.
A TIGHTENING PRESSURE GRADIENT BETWEEN THESE TWO FEATURES WILL
SUPPORT AN INCREASING SOUTHWEST WIND FLOW ACROSS THE FORECAST AREA
THE REMAINDER OF TODAY...WITH BREEZY CONDITIONS DEVELOPING BY
EARLY AFTERNOON. AMPLE MOISTURE AND INSTABILITY VIA 12Z RAOB DATA
IS ALREADY SUPPORTING SCATTERED SHOWERS AND A FEW STORMS MOVING IN
FROM THE GULF EARLY THIS MORNING...AND THIS CONVECTION WILL
CONTINUE TO MOVE INLAND THE REMAINDER OF THE MORNING WITH
ADDITIONAL SHOWERS AND STORMS FIRING OFF OVER INLAND LOCATIONS
DURING THE AFTERNOON...WITH HIGHEST RAIN CHANCES (POPS 30 TO 50
PERCENT RANGE) LIKELY FROM TAMPA TO LAKELAND NORTHWARD THROUGH THE
NATURE COAST WHERE THE DEEPEST MOISTURE WILL RESIDE...WITH SLIGHTLY
LOWER CHANCES FAR SOUTH. CURRENT FORECAST IS ON TRACK... BUT WILL
INCREASE WINDS A BIT IN A MID MORNING UPDATE GIVEN 12Z RAOB DATA
AND EXPECTED TRENDS. STORM MOTION TODAY WILL BE FASTER COMPARED TO
YESTERDAY...BUT EVEN SO MOISTURE RICH AIR MASS SHOULD STILL ALLOW
FOR SOME LOCALLY HEAVY RAINFALL AMOUNTS IN SOME LOCATIONS. MID
MORNING UPDATE SHOULD BE OUT BY 10 AM.
&&
.AVIATION...
HAVE OPTED TO MAINTAIN VFR AT ALL THE TERMINALS THROUGH THIS
EVENING...BUT WITH VCTS/CB AT TPA/PIE EARLY IN THE PERIOD. AN AREA
OF LOW PRESSURE MOVING EAST ALONG AN APPROACHING COLD FRONT WILL
BRING INCREASING MID/HIGH CLOUDS TONIGHT. TPA/PIE/ LAL/SRQ CAN
EXPECT VCSH STARTING IN THE EVENING AND VCTS LATE NIGHT. VARIABLE
WINDS BECOME SW TODAY...ROBUST AT TIMES...AND CONTINUE TONIGHT.
&&
.MARINE...
A TIGHTENING PRESSURE GRADIENT IS SUPPORTING INCREASING WINDS AND
SEAS OVER THE GULF WATERS THIS MORNING WITH WINDS ALREADY IN THE
10 TO 15 KNOT RANGE NEAR SHORE AND 14 TO 18 KNOTS OFFSHORE WITH
SEAS UP TO 5 FEET BEING NOTED AT BUOY 42036. CURRENT WINDS WILL
INCREASE A BIT MORE THE REMAINDER OF THE DAY AS MIXING TAKES PLACE
SO WILL EXPAND EXERCISE CAUTION HEADLINES FOR ALL OF THE NEAR
AND OFFSHORE WATERS FROM ENGLEWOOD NORTH TO THE SUWANNEE RIVER
OUT 60NM INCLUDING THE TAMPA BAY WATERS IN THE MID MORNING UPDATE.
WITH THE INCREASING ONSHORE FLOW THE RISK FOR RIP CURRENTS ALONG
AREA BEACHES WILL REMAIN MODERATE THE REMAINDER OF THE DAY SO
WILL KEEP THE BEACH HAZARD STATEMENT (CFW) IN PLACE FROM PINELLAS
COUNTY SOUTH TO LEE COUNTY THROUGH EARLY TONIGHT. OTHER THAN
EXPANDING THE SCEC HEADLINES...NO OTHER CHANGES EXPECTED AT THIS
TIME.
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR CHARLOTTE-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...NONE.
&&
$$
DISCUSSION/MARINE...57/MCMICHAEL
AVIATION...09/RUDE
.NEAR TERM [Through Tonight]...Just made some minor tweaks to the
fcst today, as what`s left of the Low Pressure Area in the northern
Gulf of Mexico is getting picked up by the Upper Trof and will move
onshore over the FL Panhandle today. This Low, which will continue
on its NE trek through the CWA is expected to bring likely to
categorical PoPs to the to the Tri-State area, so blended the
previous fcst PoPs with our locally derived CAM PoPs. It should also
be noted that PWATs have returned to the 2"+ level both from morning
soundings and Satellite estimates (which show them increasing
throughout the day from the SW as the Tropical moisture is pulled
back to the NE). The 08 UTC HRRR Hi-Res Model appears to have
initialized better than the WRF suite, so weighed that in when
raising PoPs a bit for this aftn. Did knock down Max Temps and
hourly temps 2-3 degrees as well, as the rain and increased cloud
cover is making rapid inroads inland already. Over the Coastal
Waters, the fcst is on track as Cautionary Conditions are already
underway, with winds and seas expected to increase just a bit out of
the SW this aftn.
&&
.Previous Discussion...
.SHORT TERM [Sunday Through Monday]...
The low over the Gulf of Mexico will lift northeastward into the FL
Panhandle today before being absorbed by the approaching cold front.
The front is forecast to reach our northwestern zones late this
afternoon and TLH around midnight before exiting southeast of the
area Sunday morning. The front will have slowed down quite a bit by
this time and may stall south of the area later on Sunday. All
guidance is pointing at a wet day today across the forecast area
today and we have maintained a high PoP forecast in the likely to
categorical range. Bulk shear is now forecast to be on the order of
20-25 knots just ahead of the front and severe weather is looking
less likely. That said, a few strong to severe storms will remain
possible. However, the primary threat will be locally heavy
rainfall. Rain chances will taper off from northwest to southeast
tonight and Sunday, but will not clear entirely out of Dixie County
until Monday morning (see table below). This will be the first
bonafide cold frontal passage of the fall season. As is typical of
these early season frontal passages, max temperatures behind the
front will not drop off all that much. However, humidity levels will
dip noticeably with dew points dropping into the upper 50s to lower
60s. Similarly, min temps will fall well into the 60s Sunday night,
with a few upper 50s possible over Southeast AL and adjacent
portions of the FL Panhandle.
&&
.LONG TERM [Monday Night through Friday]...
The extended period begins with a trough over wrn states, ridge
building E/SE to ern seaboard and trough over extreme wrn Atlc. At
surface, 1025mb high over OH/PA with strong ridge builds SWD across
Nrn Gulf. This continues NLY winds, drier air and lower humidities
advecting with somewhat tighter gradients into the local region. As
the high translates to the Mid-Atlantic states thru mid week, winds
will gradually veer to the east advecting moisture in from the
Atlantic. The surface high will slowly move east off the eastern
seaboard by the end of the week with the easterly flow continuing.
This will also begin to generate ELY surges at night especially
across the marine area. Forecast time height cross sections show
most moisture confined below 850mb with subsidence drying above as
upper ridging builds over the region thru 12Z Fri then progressively
increasing moisture. The week looks like a welcome break from the
very wet pattern that we`ve experienced this summer. The next chance
for more than isold shwrs will be on Friday and especially on
Saturday afternoons when the next upstream trough begins to suppress
deep layer ern ridge allowing for a modest increase in moisture.
Inverted surface trough also develops to our west.
Will go with NIL pops except wdly sct Fri aftn and Low sct Sat aftn.
Under NLY flow and near cloudless skies, Min temps commence 3 to 5
degrees below normal rising to near climo by Fri night. Max temps
will remain near climo. Avg inland min/max temps are 67 and 88
degrees.
&&
.AVIATION [Beginning 12Z Saturday]...
[through 12Z Sunday] Expect low stratus/CIGS to develop near the
Gulf coast as moist onshore flow continues, and filling in gradually
over S AL/S GA for the next few hours after sunrise. Will go with
reductions into MVFR range (with brief IFR at VLD). Should be high
coverage today into tonight for SHRA and even -TS in the morning at
ECP then late morning to TLH spreading to all Terminals in aftn.
Expect MVFR VSBYS/CIGS with -TSRA or VCTS 00z-06z especially VLD and
to a lesser extent TLH/ABY. After 06z, MVFR fog developing mainly at
VLD and to a lesser extent TLH with IFR likely at VLD near sunrise.
&&
.MARINE...
Winds have increased to cautionary levels over the local marine area
as low pressure just southeast of the Mississippi Delta lifts
northeast toward the Florida Panhandle. This low will reach the
Panhandle later today before being absorbed by a cold front. The
front will cross the waters from northwest to southeast tonight into
Sunday shifting winds to offshore. The front will then stall south
of the area early next week as high pressure builds into the Mid
Atlantic and Northeast. The gradient between the two systems will
increase across the eastern Gulf of Mexico. This will result in a
return of cautionary level winds to the forecast area from Tuesday
into Wednesday.
&&
.FIRE WEATHER...
A cold front will move across the local area thru Sunday spreading
ample showers, thunderstorms and gusty winds. In its wake, noticeably
drier air will overspread the region from north to south. Minimum RH
on Sunday afternoon will drop to the mid 30s across the inland FL
Panhandle but should remain above critical levels. Red flag
conditions are not expected during the upcoming work week.
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Gould
SHORT TERM...Wool
LONG TERM...Block
AVIATION...Block/Gould
MARINE...Block
FIRE WEATHER...Block
AREA FORECAST DISCUSSION
NWS GOODLAND KS
538 AM MDT SAT SEP 8 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 228 AM MDT SAT SEP 8 2012
03Z WATER VAPOR IMAGERY AND RUC 1.5 PVU SFC INDICATED SHORTWAVE
TROUGH MOVING INTO SOUTHERN KANSAS WITH LARGE AREA OF
DRYING/SUBSIDENCE OBSERVED OVER THE CWA. AT THE SFC...1024 MB SFC
HIGH WAS SETTLING OVER THE AREA WITH TDS IN THE UPPER 30S OBSERVED TO
THE NORTHWEST OF CWA.
MAIN SHORT TERM FORECAST CONCERNS WILL CENTER AROUND TEMPERATURES
AND POTENTIAL FIRE WX IMPACTS AS HIGH AMPLITUDE RIDGE WILL BE
DOMINANT WEATHER FEATURE ACROSS THE AREA THROUGH THE REST OF THE
WEEKEND.
TODAY-SUNDAY...STRONG SUBSIDENCE BEHIND DEPARTING SHORT WAVE TROUGH
WILL NOT ONLY CLEAR OUT CLOUDS ACROSS THE AREA BUT LEAVE IN ITS WAKE
A STABLE MID LEVEL TEMPERATURE PROFILE TODAY AS HIGH AMPLITUDE RIDGE
BEGINS TO BUILD OVER THE REGION. WITH SUCH A STABLE PROFILE...WINDS
ALOFT NOT INDICATING ANY SIGNIFICANT MOISTURE ADVECTION AND LITTLE
OF ANY LARGE SCALE FORCING FOR ASCENT...THINK CURRENT FORECAST OF
DRY CONDITIONS LOOKS REASONABLE AND DO NOT SEE NEED FOR ANY MAJOR
ADJUSTMENTS.
TEMPERATURES WILL BE SEVERAL DEGREES WARMER TODAY THAN YESTERDAY
WITH FULL SUN AND LIGHT WINDS ALLOWING FOR AMPLE SFC HEATING AND
EXPECT MOST OF THE CWA TO BE AT OR ABOVE 80 DEGREES. SUNDAY A BIT
TRICKIER AS STRONG MODEL AGREEMENT THAT BACKDOOR COLD FRONT WILL
MOVE INTO THE AREA DURING THE EARLY MORNING HOURS...FORCED BY SHORT
WAVE TROUGH MOVING THROUGH THE NORTHERN PLAINS. STILL EXPECT LOTS OF
SUNSHINE/FULL MIXING SO AM HESITANT TO COOL THINGS OFF TO MUCH...BUT
THINK BACKING OFF A FEW DEGREES ON HIGH TEMPS IS IN ORDER.
AFTERNOON HUMIDITIES WILL FALL INTO THE TEENS TODAY AND AGAIN
TOMORROW...INCREASING FIRE WX CONCERNS. WINDS FOR THE MOST PART WILL
BE LIGHT AND VARIABLE TODAY...WITH ONLY AREA WHERE A FEW STRONGER
GUSTS ARE EXPECTED IS AROUND MCK AS THEY ARE CLOSER TO STRONGER
HEIGHT GRADIENT. OVERALL CONDITIONS TOO MARGINAL FOR A FIRE
HIGHLIGHT. SUNDAY IS A BIT MORE COMPLICATED AS SFC TROUGH WILL
STRENGTHEN THROUGH THE DAY...WIT STRONGEST PRESSURE
GRADIENT/SUSTAINED WINDS EXPECTED ACROSS EASTERN COLORADO. MIXED
LAYER DEWPOINTS COMBINED WITH WEIGHTED MODEL DATA WOULD SUPPORT
AFTERNOON HUMIDITIES IN THE 12-15 PERCENT RANGE AS WELL. HOWEVER
COLD FRONT IN THE AREA POSSIBLE KEEPING TEMPS COOLER AND LARGE TD
SPREADS NOTED ON SREF PLUMES...CONFIDENCE NOT HIGH ENOUGH FOR A FIRE
WEATHER WATCH AT THIS POINT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 228 AM MDT SAT SEP 8 2012
SUNDAY NIGHT-MONDAY NIGHT...HIGH AMPLITUDE RIDGE WILL GRADUALLY
SHIFT EAST OVER THE AREA AND WEAKEN SOMEWHAT THROUGH THE PERIOD AS
STRONG TROUGH ADVANCES ACROSS THE NORTHWEST CONUS. MAIN IMPACT FOR
THE AREA WILL BE WARMING MAX AND MIN TEMPS THROUGH THE PERIOD. WITH
LITTLE IN THE WAY OF MOISTURE ADVECTION DO NOT ANTICIPATE ANY
MEANINGFUL PRECIP THREAT DESPITE STEEPENING LAPSE RATES AND SFC
TROUGH IN AREA. POTENTIAL FOR WIDESPREAD CRITICAL FIRE WX CONDITIONS
WILL EXIST ACROSS MUCH OF THE AREA ON MONDAY AS SFC TROUGH SHIFTS TO
THE EAST BRINGING GUSTY SOUTHERLY WINDS TO THE AREA. WITH THIS
PERIOD BEING IN THE 60-72 HOUR TIME RANGE...CONFIDENCE NOT HIGH
ENOUGH FOR A WATCH ISSUANCE BUT WILL HAVE TO MONITOR CLOSELY AS
MONDAY APPROACHES.
STARTING ON TUESDAY AND THROUGH THE EXTENDED PERIOD THE REGION WILL
BE UNDER THE INFLUENCE OF A DEEP SLOW MOVING TROUGH. AT THIS TIME
THE FIRST IN A SERIES OF IMPULSES MOVING THROUGH THE FLOW WILL COME
ACROSS THE REGION ON TUESDAY ALLOWING FOR A COLD FRONT TO MOVE INTO
THE CWA TUESDAY NIGHT INTO WEDNESDAY. BETWEEN THE FORCING ASSOC WITH
THE IMPULSE AND FRONT...COUPLED WITH LIMITED INSTABILITY...SHOULD
SET THE STAGE FOR TSRA/SHRA LATE TUE AFTERNOON/NIGHT AND INTO
WEDNESDAY BEHIND THE FRONT. PRECIP CHANCES REMAIN THEREAFTER BUT
MORE LIMITED IN COVERAGE AS ANOTHER IMPULSE MOVES ACROSS ON THURSDAY
BUT LACKING THE INSTABILITY AND FORCING COMPARED TO TUESDAY
NIGHT/WEDNESDAY. THE PARENT TROUGH AXIS IS PROGGED BY THE 00Z GFS
AND EC TO MOVE EAST OF THE CWA ON FRIDAY WITH RISING HEIGHTS OVER
THE CNTRL HIGH PLAINS WHICH SHOULD CUT OFF PRECIP OPPORTUNITIES AT
THAT POINT. HIGH TEMPERATURES ON TUESDAY WILL BE SLIGHTLY ABOVE
NORMAL AHEAD OF THE COLD FRONT BUT THEN DROP BELOW NORMAL THROUGH
THE REST OF THE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM MDT SAT SEP 8 2012
VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS AS SFC RIDGE BRING
LIGHT WEST NORTHWESTERLY WINDS AND CLEAR SKIES PREVAIL.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...05/JRM
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
945 AM MST SAT SEP 8 2012
.SYNOPSIS...
A VERY MOIST AND UNSTABLE MONSOON AIRMASS WILL CONTINUE TO COVER THE
REGION THROUGH EARLY NEXT WEEK...AND LEAD TO A CHANCE OF SHOWERS AND
THUNDERSTORMS EACH DAY. THUNDERSTORM COVERAGE AND INTENSITY WILL
VARY FROM DAY TO DAY...WITH SOMEWHAT BETTER CHANCES EXPECTED OVER
THE WEEKEND AND INTO MONDAY. HIGH TEMPERATURES WILL REMAIN BELOW
SEASONAL NORMALS EACH DAY GIVEN THE HIGH MOISTURE CONTENT IN THE
ATMOSPHERE.
&&
.DISCUSSION...
LATEST RAP INDICATES THE CENTER OF THE CYCLONIC CIRCULATION HAS
DRIFTED SOUTHWESTWARD INTO THE GULF OF CALIFORNIA. THIS PLACES THE
STRONGEST MID-LEVEL NORTHEASTERLY FLOW AND EFFECTIVE SHEAR NEAR
YUMA. LATEST 12Z NAM APPEARS TO HAVE INITIALIZED WELL AND SUGGESTS
THE STRONGEST UVV AND PRECIPITATION CHANCES WILL BE CONCENTRATED
ACROSS SOUTHERN AZ. THIS SEEMS REASONABLE AND IS REFLECTED IN THE
CURRENT FORECAST. ONLY MINOR ADJUSTMENTS TO SHORT-TERM MAX/HOURLY
TEMPERATURES AND DEWPOINTS WERE NEEDED THIS MORNING.
&&
.PREVIOUS DISCUSSION...
EARLY MORNING SATELLITE AND RADAR IMAGERY REVEALS ABUNDANT CLOUD
COVER ACROSS THE REGION...WITH A DECAYING COMPLEX OF STORMS ACROSS
SOUTHERN NEW MEXICO AND A WEAK CIRCULATION NOTED ACROSS SOUTHERN
ARIZONA. ONCE AGAIN THERE WAS ABUNDANT MOISTURE ACROSS THE AREA WITH
BLENDED TPW PRODUCT INDICATING NEARLY 1.8 INCHES OF PW /NEARLY 200
PERCENT OF NORMAL/ ACROSS THE AREA ALTHOUGH THIS IS EXPECTED TO
INCREASE LATER TODAY.
WHAT ENDED UP BEING AN EXTREMELY ACTIVE DAY YESTERDAY MAY NOT END UP
HINDERING OUR CHANCES OF STORMS TODAY. TYPICALLY ITS HARD TO GET
BACK TO BACK DAYS OF STORMS /LOOKING AT SOUNDINGS AROUND THE AREA AT
00Z ITS EASY TO SEE THE BOUNDARY LAYER HAS BEEN OVERTURNED
SUBSTANTIALLY/...HOWEVER AN INVERTED TROUGH PRESENTLY APPROACHING
THE AREA FROM THE EAST AND ITS ASSOCIATED DYNAMICS SHOULD BE ENOUGH
TO COMPENSATE FOR THE WELL OVERTURNED BOUNDARY LAYER. A FEW AIRCRAFT
SOUNDINGS INDICATE THERE IS SOME CAPE TO BE HAD IN THE MID LEVELS OF
THE ATMOSPHERE AND SURE ENOUGH...RADAR IMAGERY IS STARTING TO HINT
AT A FEW VERY LIGHT SHOWERS DEVELOPING ACROSS ARIZONA AS OF 09Z. HOW
QUICKLY STORMS WILL BLOSSOM HAS YET TO BE SEEN BUT GIVEN THE FACT
THAT THEY ARE ALREADY FORMING...I AM INCLINED TO BRING IN POPS
EARLIER THAN USUAL TO ALL LOCATIONS. FOR THE MORNING I WILL GO WITH
10-20 PERCENT POPS BUT QUICKLY INCREASE TO 30-40 FOR THE
AFTERNOON/EVENING. IM A LITTLE HESITANT TO GO MUCH HIGHER THAN
30-40 PERCENT GIVEN JUST HOW POOR THE 00Z SOUNDING LOOKED AT PHOENIX
LAST NIGHT BUT MAY TREND UPWARD AT THE LAST MINUTE ONCE THE 06Z
NAM/GFS ARE BOTH AVAILABLE.
MUCH OF THE SAME IS EXPECTED ON SUNDAY AS THE SLOW MOVING INVERTED
TROUGH WILL REMAIN NEARLY STATIONARY. IF ANYTHING...THE BEST CHANCE
FOR PRECIP MAY BE ORIENTED WEST OF PHOENIX ACROSS SW ARIZONA AND SE
CALIFORNIA. THIS IS WELL AGREED UPON BY THE MODELS AND FITS WELL
CONCEPTUALLY WITH THE PREVIOUS FORECAST AND NO MAJOR CHANGES WERE
MADE.
MONDAY STILL LOOKS TO BE THE MOST ACTIVE DAY AS THE WESTERLIES START
TO APPROACH THE AREA AND THE MAIN UPPER TROUGH FINALLY MOVES THROUGH
THE AREA. GIVEN GOOD MODEL AGREEMENT AMONG ALL MAJOR OPERATIONAL
MODELS AS WELL AS FAVORABLE CONVECTIVE PARAMETERS FROM THE SREF...I
RAISED POPS FURTHER ON MONDAY WITH ALMOST THE ENTIRE CWA IN THE
50-60 PERCENT RANGE. MLCAPES AOA 1500 J/KG WITH MIXING RATIOS STILL
IN THE 12-14 G/KG BALLPARK. SEE NO REASON AT THIS POINT TO BACK OFF
GIVEN FAVORABLE DYNAMICAL SUPPORT.
THE FORECAST FROM TUESDAY ONWARD IS ONE OF A GRADUAL DRYING TREND
WITH STEADILY DECREASING POPS AND SLOWLY INCREASING TEMPERATURES. A
FEW SHOWERS ARE POSSIBLE ON TUESDAY MAINLY NORTH AND EAST OF PHOENIX
/THE GFS AND EURO ARE STARTING TO CONVERGE ON A SLIGHTLY SLOWER
SOLUTION THAN THEY WERE SHOWING WEDNESDAY/...OTHERWISE POP CHANCES
ARE IN THE SINGLE DIGITS OR BARELY 10 PERCENT INTO NEXT WEEKEND.
LOW CONFIDENCE TEMPERATURE FORECAST TODAY THROUGH MONDAY...LOOK WHAT
HAPPENED ON FRIDAY WITH SOME LOCATIONS ACROSS SE CALIFORNIA TOPPING
OUT ABOVE 100 WHILE PHOENIX COULD ONLY GET INTO THE MID 80S /SOME
LOCATIONS IN THE EAST VALLEY BARELY GOT OUT OF THE MID 70S ALL DAY/.
I STEERED CLEAR OF THE NORMALLY FAVORABLE BIAS CORRECTED GUIDANCE
AND TRENDED THE FORECAST TOWARD THE COOLER RAW NAM/SREF VALUES.
HIGHS EACH DAY THIS WEEKEND COULD REMAIN IN THE 90S GIVEN ABUNDANT
CLOUD COVER...SATURATED GROUND...AND NEARBY SHOWERS. IF STORMS FAIL
TO DEVELOP AS PLANNED...LOOK FOR HIGHS CLOSER TO SEASONAL NORMALS
JUST ABOVE 100. TEMPS TOWARD THE MIDDLE/END OF NEXT WEEK WILL CLIMB
SLIGHTLY...BACK TO NEAR OR SLIGHTLY ABOVE NORMAL.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA...AND KSDL...
ABUNDANT MOISTURE REMAINS IN PLACE AS ANOTHER WEATHER DISTURBANCE
APPROACHES FROM THE SOUTH-SOUTHWEST. YESTERDAYS PRECIP MAY HAVE HAD
A STABILIZING EFFECT ON THE PHOENIX AREA AN IT IS UNCLEAR IF THE
DISTURBANCE WILL PROVIDE ENOUGH LIFT TO OVERCOME THAT.
HOWEVER...GIVEN ALL THE MOISTURE AVAILABLE...IT IS UNLIKELY THAT
THERE WONT AT LEAST BE SHWRS/TSTMS IN THE VICINITY OF THE TAF SITES
FOR MUCH OF THE DAY...ESPECIALLY AFTER 18Z. ANY STORMS THAT DO FORM
WILL BE CAPABLE OF REDUCING VISIBILITY IN HEAVY RAIN. THE STRONGEST
STORMS WILL ALSO BE CAPABLE OF SMALL HAIL AND GUSTS AOA 30 KTS.
ANTICIPATE STORM THREAT TO TRAIL OFF DURING THE EVENING.
OTHERWISE...WINDS TODAY WILL PRIMARILY BE FROM THE EAST AND
SOUTHEAST AND BE GUSTY AT TIMES AS SURFACE HIGH PRESSURE STRENGTHENS
OVER NEW MEXICO.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
ANOTHER WEATHER DISTURBANCE APPROACHING FROM THE SOUTH IS EXPECTED
TO MAKE FOR A MORE ACTIVE STORM DAY. EXPECT SHWRS/TSTMS TO BE WITHIN
THE VICINITY OF THE TAF SITES AT TIMES...ESPECIALLY AFTER 18Z. ANY
STORMS THAT DO FORM WILL BE CAPABLE OF REDUCING VISIBILITY IN HEAVY
RAIN. THE STRONGEST STORMS WILL ALSO BE CAPABLE OF SMALL HAIL AND
GUSTS AOA 30 KTS. ANTICIPATE STORM THREAT TO TRAIL OFF LATE TONIGHT.
OTHERWISE...WINDS TODAY WILL PRIMARILY BE FROM THE SOUTHEAST.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
LINGERING MOISTURE WILL MAINTAIN AN ELEVATED CHANCE OF THUNDERSTORMS
MONDAY BEFORE BEGINNING TO TREND DOWN TUESDAY AS DRIER AIR FROM THE
WEST BEGINS MOVING IN. STORM CHANCES WILL BE LIMITED TO
SOUTH-CENTRAL ARIZONA BY WEDNESDAY WITH COMPLETELY DRY CONDITIONS
EXPECTED BY FRIDAY. HUMIDITIES WILL FOLLOW THE SAME TREND THOUGH
MINIMUM VALUES ARE EXPECTED TO REMAIN ABOVE 15 PERCENT AND OVERNIGHT
MAXIMUMS ABOVE 35 PERCENT. APART FROM THUNDERSTORM OUTFLOWS...NO
STRONG WINDS ARE ANTICIPATED. AFTERNOON WINDS ARE EXPECTED TO FAVOR
SOUTHWEST AND WESTERLY DIRECTIONS FOR MOST AREAS BEGINNING TUESDAY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...HIRSCH
PREVIOUS DISCUSSION...LEINS
AVIATION...AJ
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1117 AM MDT SAT SEP 8 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 228 AM MDT SAT SEP 8 2012
03Z WATER VAPOR IMAGERY AND RUC 1.5 PVU SFC INDICATED SHORTWAVE
TROUGH MOVING INTO SOUTHERN KANSAS WITH LARGE AREA OF
DRYING/SUBSIDENCE OBSERVED OVER THE CWA. AT THE SFC...1024 MB SFC
HIGH WAS SETTLING OVER THE AREA WITH TDS IN THE UPPER 30S OBSERVED TO
THE NORTHWEST OF CWA.
MAIN SHORT TERM FORECAST CONCERNS WILL CENTER AROUND TEMPERATURES
AND POTENTIAL FIRE WX IMPACTS AS HIGH AMPLITUDE RIDGE WILL BE
DOMINANT WEATHER FEATURE ACROSS THE AREA THROUGH THE REST OF THE
WEEKEND.
TODAY-SUNDAY...STRONG SUBSIDENCE BEHIND DEPARTING SHORT WAVE TROUGH
WILL NOT ONLY CLEAR OUT CLOUDS ACROSS THE AREA BUT LEAVE IN ITS WAKE
A STABLE MID LEVEL TEMPERATURE PROFILE TODAY AS HIGH AMPLITUDE RIDGE
BEGINS TO BUILD OVER THE REGION. WITH SUCH A STABLE PROFILE...WINDS
ALOFT NOT INDICATING ANY SIGNIFICANT MOISTURE ADVECTION AND LITTLE
OF ANY LARGE SCALE FORCING FOR ASCENT...THINK CURRENT FORECAST OF
DRY CONDITIONS LOOKS REASONABLE AND DO NOT SEE NEED FOR ANY MAJOR
ADJUSTMENTS.
TEMPERATURES WILL BE SEVERAL DEGREES WARMER TODAY THAN YESTERDAY
WITH FULL SUN AND LIGHT WINDS ALLOWING FOR AMPLE SFC HEATING AND
EXPECT MOST OF THE CWA TO BE AT OR ABOVE 80 DEGREES. SUNDAY A BIT
TRICKIER AS STRONG MODEL AGREEMENT THAT BACKDOOR COLD FRONT WILL
MOVE INTO THE AREA DURING THE EARLY MORNING HOURS...FORCED BY SHORT
WAVE TROUGH MOVING THROUGH THE NORTHERN PLAINS. STILL EXPECT LOTS OF
SUNSHINE/FULL MIXING SO AM HESITANT TO COOL THINGS OFF TO MUCH...BUT
THINK BACKING OFF A FEW DEGREES ON HIGH TEMPS IS IN ORDER.
AFTERNOON HUMIDITIES WILL FALL INTO THE TEENS TODAY AND AGAIN
TOMORROW...INCREASING FIRE WX CONCERNS. WINDS FOR THE MOST PART WILL
BE LIGHT AND VARIABLE TODAY...WITH ONLY AREA WHERE A FEW STRONGER
GUSTS ARE EXPECTED IS AROUND MCK AS THEY ARE CLOSER TO STRONGER
HEIGHT GRADIENT. OVERALL CONDITIONS TOO MARGINAL FOR A FIRE
HIGHLIGHT. SUNDAY IS A BIT MORE COMPLICATED AS SFC TROUGH WILL
STRENGTHEN THROUGH THE DAY...WIT STRONGEST PRESSURE
GRADIENT/SUSTAINED WINDS EXPECTED ACROSS EASTERN COLORADO. MIXED
LAYER DEW POINTS COMBINED WITH WEIGHTED MODEL DATA WOULD SUPPORT
AFTERNOON HUMIDITIES IN THE 12-15 PERCENT RANGE AS WELL. HOWEVER
COLD FRONT IN THE AREA POSSIBLE KEEPING TEMPS COOLER AND LARGE TD
SPREADS NOTED ON SREF PLUMES...CONFIDENCE NOT HIGH ENOUGH FOR A FIRE
WEATHER WATCH AT THIS POINT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 228 AM MDT SAT SEP 8 2012
SUNDAY NIGHT-MONDAY NIGHT...HIGH AMPLITUDE RIDGE WILL GRADUALLY
SHIFT EAST OVER THE AREA AND WEAKEN SOMEWHAT THROUGH THE PERIOD AS
STRONG TROUGH ADVANCES ACROSS THE NORTHWEST CONUS. MAIN IMPACT FOR
THE AREA WILL BE WARMING MAX AND MIN TEMPS THROUGH THE PERIOD. WITH
LITTLE IN THE WAY OF MOISTURE ADVECTION DO NOT ANTICIPATE ANY
MEANINGFUL PRECIP THREAT DESPITE STEEPENING LAPSE RATES AND SFC
TROUGH IN AREA. POTENTIAL FOR WIDESPREAD CRITICAL FIRE WX CONDITIONS
WILL EXIST ACROSS MUCH OF THE AREA ON MONDAY AS SFC TROUGH SHIFTS TO
THE EAST BRINGING GUSTY SOUTHERLY WINDS TO THE AREA. WITH THIS
PERIOD BEING IN THE 60-72 HOUR TIME RANGE...CONFIDENCE NOT HIGH
ENOUGH FOR A WATCH ISSUANCE BUT WILL HAVE TO MONITOR CLOSELY AS
MONDAY APPROACHES.
STARTING ON TUESDAY AND THROUGH THE EXTENDED PERIOD THE REGION WILL
BE UNDER THE INFLUENCE OF A DEEP SLOW MOVING TROUGH. AT THIS TIME
THE FIRST IN A SERIES OF IMPULSES MOVING THROUGH THE FLOW WILL COME
ACROSS THE REGION ON TUESDAY ALLOWING FOR A COLD FRONT TO MOVE INTO
THE CWA TUESDAY NIGHT INTO WEDNESDAY. BETWEEN THE FORCING ASSOC WITH
THE IMPULSE AND FRONT...COUPLED WITH LIMITED INSTABILITY...SHOULD
SET THE STAGE FOR TSRA/SHRA LATE TUE AFTERNOON/NIGHT AND INTO
WEDNESDAY BEHIND THE FRONT. PRECIP CHANCES REMAIN THEREAFTER BUT
MORE LIMITED IN COVERAGE AS ANOTHER IMPULSE MOVES ACROSS ON THURSDAY
BUT LACKING THE INSTABILITY AND FORCING COMPARED TO TUESDAY
NIGHT/WEDNESDAY. THE PARENT TROUGH AXIS IS PROGGED BY THE 00Z GFS
AND EC TO MOVE EAST OF THE CWA ON FRIDAY WITH RISING HEIGHTS OVER
THE CNTRL HIGH PLAINS WHICH SHOULD CUT OFF PRECIP OPPORTUNITIES AT
THAT POINT. HIGH TEMPERATURES ON TUESDAY WILL BE SLIGHTLY ABOVE
NORMAL AHEAD OF THE COLD FRONT BUT THEN DROP BELOW NORMAL THROUGH
THE REST OF THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1111 AM MDT SAT SEP 8 2012
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. NORTHWEST WINDS AROUND
10 MPH WILL BE COMMON THROUGH THE AFTERNOON AS A SURFACE HIGH
PRESSURE OVER THE CENTRAL PLAINS MOVES SOUTH. OVERNIGHT WINDS
WILL BE LIGHT AS A COLD FRONT AND SURFACE HIGH PRESSURE MOVE INTO
THE AREA. THE LIGHT WINDS WILL CONTINUE SUNDAY AS THE COLD FRONT
AND SURFACE HIGH DRIFT EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...05/JRM
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
634 PM EDT SAT SEP 8 2012
.SYNOPSIS...
ISSUED AT 252 PM EDT SAT SEP 8 2012
EXPECT SHOWERS AND ISOLATED THUNDERSTORMS NEAR LAKE MICHIGAN
TONIGHT. THAT ACTIVITY WILL DIMINISH BY MID MORNING SUNDAY.
OTHERWISE EXPECT COOLER WEATHER TO PREVAIL INTO THE BEGINNING OF
THE WEEK. A WARMING TREND WILL BEGIN BY TUESDAY THAT WILL LAST
INTO THE END OF THE WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 252 PM EDT SAT SEP 8 2012
THE PRIMARY FORECAST CONCERN IS THE AREA OF SHOWERS MOVING
SOUTHEAST FROM WESTERN UPPER MICHIGAN AND HOW IT WILL IMPACT
SOUTHWEST LOWER MICHIGAN OVERNIGHT AS IT MOVES THROUGH.
OTHERWISE...I EXPECT TEMPERATURES TO FALL INTO THE 30S NEAR ROUTE
10 EAST OF THE LAKE SHORE SUNDAY NIGHT. AN EARLY TASTE OF FALL FOR
SURE.
A STRONG SHORTWAVE... WELL DEFINED ON THE WATER VAPOR LOOPS...
WILL CONTINUE TO DROP SOUTHEAST CROSSING SOUTHWEST LOWER MICHIGAN
DURING THE EARLY EVENING HOURS. THERE IS A 130 KNOT JET EXIT
REGION THAT CROSSES SOUTHERN LAKE MICHIGAN JUST BEFORE MIDNIGHT
ASSOCIATED WITH FEATURE. THIS JET CORE IS ROTATING AROUND THE BASE
OF THE CLOSED 300 MB LOW THAT IS ALSO ASSOCIATED WITH THIS
FEATURE. BOTH THE NAM12 AND HRRR RUC SUGGEST A MESO-LOW FEATURE
WILL DEVELOP ON THE EAST SIDE (MICHIGAN SIDE)OF THE LAKE AN TRACK
SOUTH THROUGH THE NIGHT ENHANCING THE CONVERGENCE OVER THE LAKE.
GIVEN THE 850 MB TO LAKE TEMP DIFFERENCE IS NEAR 15C. BUFKIT SHOWS
THE EQUILIBRIUM LEVEL OVERNIGHT WILL APPROACH 30000 FT AGL WITH
NEARLY 2000 J/KG OF LAKE EDUCED CAPE. I AM THINKING THIS IS
ENOUGH FOR SCT TO ISOLATED THUNDERSTORMS. LOCALLY HEAVY SHOWERS
SHOULD BE EXPECTED. THAT THINKING IS CONFIRMED BY THE SPC SREF.
NEARLY ALL OF THIS WILL MOSTLY BE OVER LAKE MICHIGAN AND WEST OF
US-131 WHERE THE LAKE EDUCED INSTABILITY WILL BE A FACTOR. INLAND
OF THAT EXPECT PARTLY CLOUDY SKIES WITH POSSIBLY A PASSING SHOWER
AS THE UPPER WAVE MOVE THROUGH.
ONCE THIS FEATURE EXITS THE AREA MID TO LATE MORNING SUNDAY THE
UPPER RIDGE BUILDS IN THROUGH TUESDAY. THERE WILL BE ENOUGH
INSTABILITY YET FOR ISOLATED SHOWERS SOUTH OF ROUTE 10 AND EAST OF
US-131 SUNDAY AFTERNOON SINCE THE UPPER JET WILL NOT BE EAST OF
THERE YET.
SUNDAY NIGHT WITH SURFACE HIGH PRESSURE OVER THE AREA WINDS WILL
BE LIGHT AND SKIES CLEAR. I EXPECT LOWS IN THE MID 30S OVER OUR NE
CWA AND LOWER TO MID 40S ELSEWHERE. A SLOW WARMING TREND FOLLOWS
THEN WITH MOSTLY CLEAR SKIES THROUGH TUESDAY NIGHT.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 305 PM EDT SAT SEP 8 2012
WE/LL START TO WARM UP AGAIN TUESDAY AS THE HIGH MOVES TOWARD NEW
ENGLAND. THE NEXT COLD FRONT WILL LIKELY MOVE ACROSS THE CWA
THURSDAY NIGHT OR FRIDAY. INSTABILITY DOESN/T LOOK VERY IMPRESSIVE
WITH THIS NOR DO THE MOISTURE TRANSPORT VECTORS. AS A RESULT I
CAN/T SEE MUCH MORE THAN SLIGHT CHC POPS AT THIS POINT. THERE IS A
COMPACT SHORT WAVE ASSOCIATED WITH THIS AND THAT MAY BOOST PCPN
CHANCES INTO SATURDAY...BUT GIVEN THE SFC RIDGING MOVING IN AT
THAT POINT...PCPN AMOUNTS AND CHANCES LOOK MEAGER.
TEMPS WILL CLIMB TO AROUND 80 PRIOR TO FROPA AND THAN BACK INTO THE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 146 PM EDT SAT SEP 8 2012
THERE IS CERTAINLY A DIURNAL LOOK TO THE CU FIELD AND WE/LL SEE
ISOLD SHRA DIMINISH TOWARD SUSET AND SKIES WILL BECOME CLR-SCT.
HOWEVER STRATOCU WILL INCREASE LATE TONIGHT AS THE NEXT COLD FRONT
DROPS SOUTH. WINDS WILL VEER TO THE NNW 12Z-15Z AND CIGS SHOULD
DEVELOP AROUND 4K FT.
&&
.MARINE...
ISSUED AT 633 PM EDT SAT SEP 8 2012
ISSUED ANOTHER SCA FOR THE NRN ZONE. GUSTY WINDS EXPECTED WITH THE
NEXT COLD FRONT CURRENTLY MOVING ACROSS WISCONSIN.
&&
.HYDROLOGY...
ISSUED AT 252 PM EDT SAT SEP 8 2012
RIVERS WILL CONTINUE TO FALL SLOWLY THROUGH THIS COMING WEEK AS
IT IS EXPECTED TO BE DRY MOST OF THIS COMING WEEK. ANY RAINFALL
WE GET TONIGHT WILL ONLY BE NEAR THE LAKE SHORE AND THAT WILL NOT
IMPACT MOST OF RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR LMZ847>849.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR LMZ844>846.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...93
AVIATION...93
HYDROLOGY...WDM
MARINE...93
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
428 PM EDT SAT SEP 8 2012
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 426 PM EDT SAT SEP 8 2012
MAIN FOCUS OF THE SHORT TERM IS THE STRONG SHORTWAVE SLIDING SSE
THROUGH NE MN AND WRN LK SUPERIOR AND THE ASSOCIATED SFC COLD FRONT.
AHEAD OF THIS SHORTWAVE...AREA OF SHOWERS HAS DROPPED OUT OF CANADA
THIS MORNING AND INTO FAR WRN UPPER MI. EXPECT THESE SHOWERS TO
CONTINUE TO SLIDE TO THE SE OVER THE COUNTIES NEAR THE WI BORDER
THROUGH THE REST OF THIS AFTN...ASSOCIATED WITH THE H850-500
Q-VECTOR CONV. BEHIND THIS INITIAL AREAS OF SHOWERS AND THE
FRONT...SCATTERED SHOWERS HAVE DEVELOPED UNDER THE CENTER OF THE
SHORTWAVE AND ASSOCIATED WITH AREA OF STEEP MID LVL LAPSE RATES.
THESE SHOWERS SHOULD CONTINUE TO THE SSE AND LARGELY MISS THE
CWA...BUT COULD SEE SOME SCATTERED SHOWERS OVER THE WEST UNTIL
DIURNAL HEATING IS LOST AND THE SHORTWAVE SLIDES S OF THE CWA.
ATTENTION THEN TURNS TO POTENTIAL LK ENHANCED SHOWERS AND CLOUDS FOR
TONIGHT. RUC ANALYSIS IS SHOWING THAT H850 TEMPS HAVE WARMED A
DEGREE OR TWO FROM THIS MORNING...TOWARDS 6-7C OVER THE WEST AHEAD
OF THE SHORTWAVE. ONCE THIS WAVE AND THE SFC FRONT SLIDE SE OF THE
AREA...EXPECT H850 TEMPS TO FALL TOWARDS 5C BY THIS EVENING AND THEN
4C BY 12Z SUN. WITH LK SUPERIOR TEMPS IN THE 17-21C RANGE...THIS
SHOULD PROVIDE DECENT DELTA-T VALUES FOR LK ENHANCED SHOWERS/CLOUDS.
THE MAIN QUESTION FOR TONIGHT INTO SUN MORNING IS THE AMNT OF
MOISTURE AND IT/S LOCATION. WITH THE TRACK OF THE SHORTWAVE AND
MOISTURE UPSTREAM INTO ONTARIO...EXPECT FAR WRN UPPER MI TO SEE THE
BEST OPPORTUNITY FOR LK ENHANCED SHOWERS UNDER THE NRLY BL FLOW.
THAT AREA WILL BE AIDED BY COASTAL CONVERGENCE AND UPSLOPE FLOW...SO
HAVE HIGH END CHANCE POPS THROUGH MUCH OF THE NIGHT. WITH A SLIGHT
DELAY TO THE COLDEST TEMPS...MAY SEE A SHORT BREAK IN THE SHOWERS
AFTER THE SUN GOES DOWN AND BEFORE THE COLD AIR ARRIVES. FARTHER NE
IS A LITTLE MORE UNCERTAIN. MODELS SHOWING H850-700 DRY AIR DROPPING
S FROM CNTRL ONTARIO AND OVER CNTRL/ERN LK SUPERIOR THIS EVENING AND
OVER CNTRL/ERN UPPER MI OVERNIGHT. WITH THE LACK OF CU THAT HAS
DEVELOPED NE OF THUNDER BAY...THAT SEEMS FAIRLY REASONABLE.
BUT...H925-850 MOISTURE AND STEEP LAPSE RATES OVER LK SUPERIOR WITH
THE NRLY FLOW SHOULD STILL PRODUCE ISOLATED TO POTENTIALLY SCATTERED
LK ENHANCED SHOWERS OVER THE NCNTRL CWA WITH THE LIMITED CLOUD DEPTH
KEEPING THEM LIGHT. ALL OF THESE SHOWERS MAY BE HELPED BY A
SECONDARY SHORTWAVE FROM NW ONTARIO MOVING THROUGH OVERNIGHT.
FOR TOMORROW...WITH LINGERING LLVL MOISTURE AND 3-4C H850
TEMPS...THE NNW WIND FAVORED LOCATIONS SHOULD SEE PARTLY/MOSTLY
CLOUDY SKIES THROUGH THE MORNING HOURS. STILL LINGERED LIGHT SHOWERS
THROUGH THE MORNING...BUT LIMITED MOISTURE DEPTH SUPPORTS ONLY
HAVING SLIGHT CHANCES. OVER THE CNTRL/EAST IN THE AFTN...MOISTURE
THAT IS CURRENTLY OVER NW ONTARIO SHOULD DROP OVER THE ERN LK AND
WITH THE COLD TEMPS REINFORCE THE CLOUD DECK. NCEP WRF NMM/ARW RUNS
HAVE SHOWN THE POTENTIAL FOR SHOWERS WITH THIS WAVE...BUT CONCERNED
DRIER AIR ALOFT WILL KEEP CLOUDS FROM DEVELOPING TOO MUCH. FARTHER
WEST...HIGH PRESSURE BUILDING IN UNDER THE UPPER RIDGING WILL HELP
BRING DRIER AIR INTO THE AREA AND DECREASE THE CLOUDS DURING THE
AFTN AND LEAD TO CLEARING AFTER 21Z.
FINALLY...WITH THE NORTHERLY WINDS CREATING 3-5FT WAVES
TOMORROW...EXPECT A MODERATE TO HIGH RISK OF RIP CURRENTS TO
CONTINUE TOMORROW.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 426 PM EDT SAT SEP 8 2012
MEDIUM RANGE GUIDANCE CONTINUES TO BE IN GENERAL AGREEMENT ON THE
BIG PICTURE OVER THE NEXT 7 DAYS AS IT PERTAINS TO UPPER MI. AFTER
THIS WEEKENDS TROF...PATTERN WILL BECOME MORE PROGRESSIVE NEXT WEEK.
THE TROF DOMINATING THE GREAT LAKES THIS WEEKEND WILL BE FOLLOWED BY
RIDGING EARLY IN THE WEEK...A TROF FOR THE MID/LATE PORTION OF THE
WEEK...AND ANOTHER TROF LATE NEXT WEEKEND. THE EVOLUTION/STRUCTURE
OF THE MID/LATE WEEK TROF REMAINS THE MAIN AREA OF MODEL
DISAGREEMENT. WITH A PROGRESSIVE PATTERN...TEMPS WILL SHOW A FAIR
AMOUNT OF VARIATION OVER THE NEXT 7 DAYS. TEMPS A LITTLE BLO NORMAL
THRU THE WEEKEND WITH TROFFING OVER THE GREAT LAKES WILL TRANSITION
TO STRONG WARMING/ABOVE NORMAL TEMPS EARLY IN THE WEEK AHEAD OF THE
NEXT APPROACHING TROF. GRADUAL COOLING WILL OCCUR MIDWEEK...LEADING
TO TEMPS AROUND NORMAL LATE IN THE WORK WEEK AS MID/UPPER LEVEL
TROF PASSES. TEMPS WILL THEN BEGIN TO REBOUND FOR THE START OF NEXT
WEEKEND. AS FOR PCPN...THIS WILL BE AN OVERALL DRY PERIOD DUE TO
LACK OF GULF MOISTURE TRANSPORT TO THE UPPER LAKES AND DUE TO MAIN
FORCING PASSING N OF THE AREA WHEN SHORTWAVES PASS.
BEGINNING SUN NIGHT...WITH SFC HIGH PRES RIDGE PASSING ACROSS THE
AREA...CLR SKIES AND PRECIPITABLE WATER 45-65PCT OF NORMAL...A GOOD
RADIATIONAL COOLING NIGHT IS EXPECTED. MINS ON THE LOW SIDE OF AVBL
GUIDANCE LOOK ON TRACK. TRADITIONAL INTERIOR COLD SPOTS SHOULD DROP
TO THE UPPER...POSSIBLY MID...30S. MIGHT SEE A LITTLE FROST.
AS MID LEVEL RIDGE SHIFTS TO THE UPPER LAKES MON...WAA WILL BE
UNDERWAY. LOW-LEVEL JET/STRONGEST PUSH OF WARMING IS WELL TO THE NNW
MON...SO PCPN IS NOT A CONCERN. TEMPS SHOULD REBOUND INTO THE 70S
UNDER WAA PATTERN.
AS THE MID LEVEL RIDGE SHIFTS E TUE AND NEXT TROF BEGINS TO MOVE OUT
OVER THE NRN PLAINS...850MB THERMAL RIDGE (TEMPS OF 16-19C) WILL
TRANSLATE OVER THE AREA. ALTHOUGH THERE REMAINS SOME CONCERN WITH
MID/HIGH CLOUD COVERAGE TUE...THERMAL RIDGE AND BREEZY S-SW WINDS
WILL LEAD TO A WARM DAY FOR EARLY/MID SEPT...ESPECIALLY OVER THE W
HALF. WILL STAY WITH HIGH TEMPS MAINLY LOW/MID 80S...ABOVE ALL
GUIDANCE IN MOST AREAS. NOT TOTALLY OUT OF THE QUESTION THAT SOME OF
THE DOWNSLOPE AREAS OVER THE W TOWARD LAKE SUPERIOR COULD FLIRT WITH
90F IF THE DAY ENDS UP SUNNY. COOLER READINGS WILL BE OVER THE E
WITH FLOW UP LAKE MICHIGAN. WITH LOW-LEVEL JET TRANSLATING ACROSS
THE AREA...THERE IS A VERY SMALL POTENTIAL FOR SOME CONVECTION...BUT
LACK OF BETTER MOISTURE MINIMIZES THE POTENTIAL.
MEDIUM RANGE GUIDANCE HAS CONTINUED TO SLOW DOWN SLIGHTLY THE COLD
FRONT ASSOCIATED WITH THE INCOMING MID LEVEL TROF MIDWEEK. IT NOW
APPEARS FRONT WILL BE CROSSING THE AREA DURING THE DAY WED. WITH
BEST DEEP LAYER FORCING PASSING WELL TO THE N AND WITH A LACK OF A
GOOD GULF MOISTURE CONNECTION...THERE SHOULDN`T BE MUCH PCPN
ASSOCIATED WITH THE FRONT. HOWEVER...WITH THE UPPER TROF TAKING ON A
POSITIVE TILT FROM HUDSON BAY TO THE NRN PLAINS THRU THU...THE
SUPPORTING SW-NE ORIENTED UPPER JET WILL SLOWLY TRANSLATE EASTWARD.
AS IT DOES...RIGHT ENTRANCE UPPER DIVERGENCE WILL BEGIN TO OVERLAY
THE LOW-LEVEL FRONT...LIKELY LEADING TO A RIBBON SHRA EVENTUALLY
DEVELOPING ALONG/BEHIND SFC FRONT AS SUGGESTED BY THE
GFS/ECMWF/GLOBAL GEM. THUS...PLAN TO MAINTAIN SCHC POPS OVER THE FAR
W LATE TUE NIGHT INTO WED WITH SCHC POPS EXPANDING INTO THE CNTRL
WED AND THEN CHC POPS OVER THE E HALF WED NIGHT. INSTABILITY IS VERY
LIMITED...SO POTENTIAL OF THUNDER IS MINIMAL. LINGERED SCHC POPS
OVER ALL BUT THE FAR W THU GIVEN MODEL TRENDS...BUT MAY NEED TO
INCREASE THU POPS TO CHC IF CONSISTENCY DEVELOPS FOR SLOW FRONTAL
MOVEMENT AND AN INCREASED POST FRONTAL PCPN BAND WITH TIME DUE TO
UPPER JET.
SINCE YESTERDAY`S RUNS...GFS/ECMWF HAVE TRENDED COOLER FOR FRI AS
THE MID/UPPER LEVEL TROF PASSES (850MB TEMPS 3-5C TO START THE DAY).
AS A RESULT...TEMPS WILL BE BACK AROUND NORMAL MID SEPT VALUES (60S
FOR HIGHS). MIGHT BE SOME LAKE EFFECT -SHRA FRI MORNING IN THE
CHILLY NW FLOW. OTHERWISE...DRY WEATHER IS EXPECTED FRI. HOWEVER...
IT IS NOTED THAT THE 00Z GFS AND NOW THE 12Z ECMWF SHOW ENERGY IN
THE SRN PORTION OF PASSING TROF SEPARATING OUT AND LEADING TO A MID
LEVEL LOW TRACKING INTO THE UPPER LAKES FRI INTO EARLY SAT. GIVEN
THE VERY INCONSISTENT SIGNAL...WILL IGNORE THIS IDEA FOR NOW. WILL
BE SOMETHING TO KEEP IN MIND WHICH MAY CHANGE THE CURRENT DRY FCST
TO A POSSIBLE GOOD SOAKING. IN THE ABSENCE OF THE POSSIBLE MID LEVEL
LOW...DRY WEATHER/WARMING IS EXPECTED SAT AS WEAK MID LEVEL RIDGE
ARRIVES. NEXT SHORTWAVE TROF SHOULD ARRIVE SUN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 133 PM EDT SAT SEP 8 2012
STRONG SHORTWAVE DROPPING SSE THROUGH NORTHERN MN ALONG WITH SFC
COLD FRONT WILL BRING SCATTERED/NUMEROUS SHOWERS TO WRN UPPER MI
THIS AFTN. THINK THE SHOWERS WILL MAINLY STAY SW OF KCMX/KSAW...SO
HAVE LEFT OUT PREDOMINATE -SHRA FOR THOSE SITES THIS AFTN. DUE TO
THE DYNAMICS WITH THE SYSTEM...THERE COULD BE A RUMBLE OF THUNDER AT
KIWD BUT NOT CONFIDENT ON PROXIMITY TO THE TAF SITE...SO HAVE LEFT
OUT.
BEHIND THE FRONT AND SHORTWAVE...EXPECT A TRANSITION TO LK ENHANCED
CLOUDS/RAIN TO OCCUR THIS EVENING AND CONTINUE THROUGH MUCH OF THE
TAF PERIOD. WITH THE BEST MOISTURE/FETCH AFFECTING KIWD...HAVE
CONTINUED THE MENTION OF MVFR CONDITIONS TONIGHT THROUGH THE MORNING
HOURS. DRIER AIR ALOFT LEADS TO MORE UNCERTAINTY ON THE COVERAGE OF
CLOUDS AND RAIN POTENTIAL AT KCMX/KSAW...SO WILL GO WITH VFR
CONDITIONS FOR NOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT SAT SEP 8 2012
A SFC TROUGH DROPPING SE ACROSS LAKE SUPERIOR THIS EVENING WILL
BRING A REINFORCING SHOT OF COLD AIR AND STRENGTHEN THE NNW WINDS
ACROSS LAKE SUPERIOR. THE HIGHEST GUSTS...TO 30KTS...WILL BE SEEN
OVER FAR WRN LK SUPERIOR...WILL THE REST OF THE LAKE WILL SEE
15-25KTS TONIGHT INTO TOMORROW. HIGH PRESSURE WILL BUILD OVER THE
UPPER GREAT LAKES TOMORROW AND LEAD TO WEAKENING WINDS SUN AFTN AND
SUNDAY NIGHT. AS THE HIGH QUICKLY SHIFTS TO THE LOWER GREAT LAKES
ON MONDAY...SOUTHERLY WINDS WILL INCREASE AND PRODUCE A PERSISTENT
PERIOD OF 15-25KT WINDS THROUGH TUESDAY NIGHT WHEN A COLD FRONT
PUSHES ACROSS LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
306 PM EDT SAT SEP 8 2012
.SYNOPSIS...
ISSUED AT 252 PM EDT SAT SEP 8 2012
EXPECT SHOWERS AND ISOLATED THUNDERSTORMS NEAR LAKE MICHIGAN
TONIGHT. THAT ACTIVITY WILL DIMINISH BY MID MORNING SUNDAY.
OTHERWISE EXPECT COOLER WEATHER TO PREVAIL INTO THE BEGINNING OF
THE WEEK. A WARMING TREND WILL BEGIN BY TUESDAY THAT WILL LAST
INTO THE END OF THE WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 252 PM EDT SAT SEP 8 2012
THE PRIMARY FORECAST CONCERN IS THE AREA OF SHOWERS MOVING
SOUTHEAST FROM WESTERN UPPER MICHIGAN AND HOW IT WILL IMPACT
SOUTHWEST LOWER MICHIGAN OVERNIGHT AS IT MOVES THROUGH.
OTHERWISE...I EXPECT TEMPERATURES TO FALL INTO THE 30S NEAR ROUTE
10 EAST OF THE LAKE SHORE SUNDAY NIGHT. AN EARLY TASTE OF FALL FOR
SURE.
A STRONG SHORTWAVE... WELL DEFINED ON THE WATER VAPOR LOOPS...
WILL CONTINUE TO DROP SOUTHEAST CROSSING SOUTHWEST LOWER MICHIGAN
DURING THE EARLY EVENING HOURS. THERE IS A 130 KNOT JET EXIT
REGION THAT CROSSES SOUTHERN LAKE MICHIGAN JUST BEFORE MIDNIGHT
ASSOCIATED WITH FEATURE. THIS JET CORE IS ROTATING AROUND THE BASE
OF THE CLOSED 300 MB LOW THAT IS ALSO ASSOCIATED WITH THIS
FEATURE. BOTH THE NAM12 AND HRRR RUC SUGGEST A MESO-LOW FEATURE
WILL DEVELOP ON THE EAST SIDE (MICHIGAN SIDE)OF THE LAKE AN TRACK
SOUTH THROUGH THE NIGHT ENHANCING THE CONVERGENCE OVER THE LAKE.
GIVEN THE 850 MB TO LAKE TEMP DIFFERENCE IS NEAR 15C. BUFKIT SHOWS
THE EQUILIBRIUM LEVEL OVERNIGHT WILL APPROACH 30000 FT AGL WITH
NEARLY 2000 J/KG OF LAKE EDUCED CAPE. I AM THINKING THIS IS
ENOUGH FOR SCT TO ISOLATED THUNDERSTORMS. LOCALLY HEAVY SHOWERS
SHOULD BE EXPECTED. THAT THINKING IS CONFIRMED BY THE SPC SREF.
NEARLY ALL OF THIS WILL MOSTLY BE OVER LAKE MICHIGAN AND WEST OF
US-131 WHERE THE LAKE EDUCED INSTABILITY WILL BE A FACTOR. INLAND
OF THAT EXPECT PARTLY CLOUDY SKIES WITH POSSIBLY A PASSING SHOWER
AS THE UPPER WAVE MOVE THROUGH.
ONCE THIS FEATURE EXITS THE AREA MID TO LATE MORNING SUNDAY THE
UPPER RIDGE BUILDS IN THROUGH TUESDAY. THERE WILL BE ENOUGH
INSTABILITY YET FOR ISOLATED SHOWERS SOUTH OF ROUTE 10 AND EAST OF
US-131 SUNDAY AFTERNOON SINCE THE UPPER JET WILL NOT BE EAST OF
THERE YET.
SUNDAY NIGHT WITH SURFACE HIGH PRESSURE OVER THE AREA WINDS WILL
BE LIGHT AND SKIES CLEAR. I EXPECT LOWS IN THE MID 30S OVER OUR NE
CWA AND LOWER TO MID 40S ELSEWHERE. A SLOW WARMING TREND FOLLOWS
THEN WITH MOSTLY CLEAR SKIES THROUGH TUESDAY NIGHT.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 305 PM EDT SAT SEP 8 2012
WE/LL START TO WARM UP AGAIN TUESDAY AS THE HIGH MOVES TOWARD NEW
ENGLAND. THE NEXT COLD FRONT WILL LIKELY MOVE ACROSS THE CWA
THURSDAY NIGHT OR FRIDAY. INSTABILITY DOESN/T LOOK VERY IMPRESSIVE
WITH THIS NOR DO THE MOISTURE TRANSPORT VECTORS. AS A RESULT I
CAN/T SEE MUCH MORE THAN SLIGHT CHC POPS AT THIS POINT. THERE IS A
COMPACT SHORT WAVE ASSOCIATED WITH THIS AND THAT MAY BOOST PCPN
CHANCES INTO SATURDAY...BUT GIVEN THE SFC RIDGING MOVING IN AT
THAT POINT...PCPN AMOUNTS AND CHANCES LOOK MEAGER.
TEMPS WILL CLIMB TO AROUND 80 PRIOR TO FROPA AND THAN BACK INTO THE
70S BY THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 146 PM EDT SAT SEP 8 2012
THERE IS CERTAINLY A DIURNAL LOOK TO THE CU FIELD AND WE/LL SEE
ISOLD SHRA DIMINISH TOWARD SUSET AND SKIES WILL BECOME CLR-SCT.
HOWEVER STRATOCU WILL INCREASE LATE TONIGHT AS THE NEXT COLD FRONT
DROPS SOUTH. WINDS WILL VEER TO THE NNW 12Z-15Z AND CIGS SHOULD
DEVELOP AROUND 4K FT.
&&
.MARINE...
ISSUED AT 252 PM EDT SAT SEP 8 2012
I WILL CONTINUE THE SMALL CRAFT ADVISORIES AS IS INTO SUNDAY. IT
SHOULD BE NOTED THAT THERE CURRENTLY ARE GUSTY WINDS BEHIND THE
TROUGH AT THE SURFACE OVER NE MINNESOTA. THE HRRR RUC SHOWS AN
AREA OF 40 TO 50 KNOT WINDS OVER THE CENTRAL PART OF LAKE MICHIGAN
JUST BEHIND THE THROUGH OVERNIGHT. SO IN THE NEAR SHORE WATERS
EXPECT WINDS TO INCREASE SIGNIFICANTLY LATER TONIGHT FOR A FEW
HOURS BEHIND THE THROUGH. ALL OF THIS WILL END FROM NORTH TO SOUTH
DURING THE DAY SUNDAY AS THE SYSTEM MOVES OUT.
&&
.HYDROLOGY...
ISSUED AT 252 PM EDT SAT SEP 8 2012
RIVERS WILL CONTINUE TO FALL SLOWLY THROUGH THIS COMING WEEK AS
IT IS EXPECTED TO BE DRY MOST OF THIS COMING WEEK. ANY RAINFALL
WE GET TONIGHT WILL ONLY BE NEAR THE LAKE SHORE AND THAT WILL NOT
IMPACT MOST OF RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ849.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR LMZ847-848.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR LMZ844>846.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...93
AVIATION...93
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
254 PM EDT SAT SEP 8 2012
.SYNOPSIS...
ISSUED AT 252 PM EDT SAT SEP 8 2012
EXPECT SHOWERS AND ISOLATED THUNDERSTORMS NEAR LAKE MICHIGAN
TONIGHT. THAT ACTIVITY WILL DIMINISH BY MID MORNING SUNDAY.
OTHERWISE EXPECT COOLER WEATHER TO PREVAIL INTO THE BEGINNING OF
THE WEEK. A WARMING TREND WILL BEGIN BY TUESDAY THAT WILL LAST
INTO THE END OF THE WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 252 PM EDT SAT SEP 8 2012
THE PRIMARY FORECAST CONCERN IS THE AREA OF SHOWERS MOVING
SOUTHEAST FROM WESTERN UPPER MICHIGAN AND HOW IT WILL IMPACT
SOUTHWEST LOWER MICHIGAN OVERNIGHT AS IT MOVES THROUGH.
OTHERWISE...I EXPECT TEMPERATURES TO FALL INTO THE 30S NEAR ROUTE
10 EAST OF THE LAKE SHORE SUNDAY NIGHT. AN EARLY TASTE OF FALL FOR
SURE.
A STRONG SHORTWAVE... WELL DEFINED ON THE WATER VAPOR LOOPS...
WILL CONTINUE TO DROP SOUTHEAST CROSSING SOUTHWEST LOWER MICHIGAN
DURING THE EARLY EVENING HOURS. THERE IS A 130 KNOT JET EXIT
REGION THAT CROSSES SOUTHERN LAKE MICHIGAN JUST BEFORE MIDNIGHT
ASSOCIATED WITH FEATURE. THIS JET CORE IS ROTATING AROUND THE BASE
OF THE CLOSED 300 MB LOW THAT IS ALSO ASSOCIATED WITH THIS
FEATURE. BOTH THE NAM12 AND HRRR RUC SUGGEST A MESO-LOW FEATURE
WILL DEVELOP ON THE EAST SIDE (MICHIGAN SIDE)OF THE LAKE AN TRACK
SOUTH THROUGH THE NIGHT ENHANCING THE CONVERGENCE OVER THE LAKE.
GIVEN THE 850 MB TO LAKE TEMP DIFFERENCE IS NEAR 15C. BUFKIT SHOWS
THE EQUILIBRIUM LEVEL OVERNIGHT WILL APPROACH 30000 FT AGL WITH
NEARLY 2000 J/KG OF LAKE EDUCED CAPE. I AM THINKING THIS IS
ENOUGH FOR SCT TO ISOLATED THUNDERSTORMS. LOCALLY HEAVY SHOWERS
SHOULD BE EXPECTED. THAT THINKING IS CONFIRMED BY THE SPC SREF.
NEARLY ALL OF THIS WILL MOSTLY BE OVER LAKE MICHIGAN AND WEST OF
US-131 WHERE THE LAKE EDUCED INSTABILITY WILL BE A FACTOR. INLAND
OF THAT EXPECT PARTLY CLOUDY SKIES WITH POSSIBLY A PASSING SHOWER
AS THE UPPER WAVE MOVE THROUGH.
ONCE THIS FEATURE EXITS THE AREA MID TO LATE MORNING SUNDAY THE
UPPER RIDGE BUILDS IN THROUGH TUESDAY. THERE WILL BE ENOUGH
INSTABILITY YET FOR ISOLATED SHOWERS SOUTH OF ROUTE 10 AND EAST OF
US-131 SUNDAY AFTERNOON SINCE THE UPPER JET WILL NOT BE EAST OF
THERE YET.
SUNDAY NIGHT WITH SURFACE HIGH PRESSURE OVER THE AREA WINDS WILL
BE LIGHT AND SKIES CLEAR. I EXPECT LOWS IN THE MID 30S OVER OUR NE
CWA AND LOWER TO MID 40S ELSEWHERE. A SLOW WARMING TREND FOLLOWS
THEN WITH MOSTLY CLEAR SKIES THROUGH TUESDAY NIGHT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 330 AM EDT SAT SEP 8 2012
LONG TERM BEGINS MONDAY NIGHT WITH RIDGING IN PLACE AT 500MB/S. THE
RIDGING REMAINS INTO WEDNESDAY MORNING. ON WEDNESDAY...A DEEP UPPER
LOW PROGRESSING ACROSS CANADA WILL FLATTEN THE GREAT LAKES
RIDGE...RESULTING IN MORE OF A ZONAL FLOW FOR THE REMAINDER OF THE
PERIOD. THE GFS AND ECMWF HAVE TIMING DIFFERENCE BUT BOTH BRING AN
UPPER SHORTWAVE TROUGH THROUGH THE REGION THE LATTER HALF OF THE
WORK WEEK.
AT THE SURFACE...HIGH PRESSURE WILL SLIP AWAY FROM THE GREAT LAKES
ON TUESDAY RESULTING IN A WARMER RETURN FLOW TUES/WED. DRY WX IS
EXPECTED FROM MONDAY NIGHT INTO WEDNESDAY NIGHT. WEAK SURFACE
TROUGHING MOVES THROUGH THE FORECAST AREA THURS/FRI. HAVE SMALL POPS
LATE WEDNESDAY NIGHT THROUGH FRIDAY AS THE TROUGH MOVES
THROUGH...BUT NOT EXPECTING SIGNIFICANT PRECIPITATION AT THIS POINT.
TEMPERATURES WILL BE ABOVE NORMAL TUES/WED IN SOUTHERLY
FLOW...DROPPING BACK CLOSER TO NORMAL BY WEEKS END. OVERALL A FAIRLY
BENIGN PATTERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 146 PM EDT SAT SEP 8 2012
THERE IS CERTAINLY A DIURNAL LOOK TO THE CU FIELD AND WE/LL SEE
ISOLD SHRA DIMINISH TOWARD SUSET AND SKIES WILL BECOME CLR-SCT.
HOWEVER STRATOCU WILL INCREASE LATE TONIGHT AS THE NEXT COLD FRONT
DROPS SOUTH. WINDS WILL VEER TO THE NNW 12Z-15Z AND CIGS SHOULD
DEVELOP AROUND 4K FT.
&&
.MARINE...
ISSUED AT 252 PM EDT SAT SEP 8 2012
I WILL CONTINUE THE SMALL CRAFT ADVISORIES AS IS INTO SUNDAY. IT
SHOULD BE NOTED THAT THERE CURRENTLY ARE GUSTY WINDS BEHIND THE
TROUGH AT THE SURFACE OVER NE MINNESOTA. THE HRRR RUC SHOWS AN
AREA OF 40 TO 50 KNOT WINDS OVER THE CENTRAL PART OF LAKE MICHIGAN
JUST BEHIND THE THROUGH OVERNIGHT. SO IN THE NEAR SHORE WATERS
EXPECT WINDS TO INCREASE SIGNIFICANTLY LATER TONIGHT FOR A FEW
HOURS BEHIND THE THROUGH. ALL OF THIS WILL END FROM NORTH TO SOUTH
DURING THE DAY SUNDAY AS THE SYSTEM MOVES OUT.
&&
.HYDROLOGY...
ISSUED AT 252 PM EDT SAT SEP 8 2012
RIVERS WILL CONTINUE TO FALL SLOWLY THROUGH THIS COMING WEEK AS
IT IS EXPECTED TO BE DRY MOST OF THIS COMING WEEK. ANY RAINFALL
WE GET TONIGHT WILL ONLY BE NEAR THE LAKE SHORE AND THAT WILL NOT
IMPACT MOST OF RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ849.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR LMZ847-848.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR LMZ844>846.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...DUKE
AVIATION...93
HYDROLOGY...WDM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
321 PM CDT SAT SEP 8 2012
.DISCUSSION.../ISSUED 320 PM CDT SAT SEP 8/
WINDS AND CLOUD COVER WILL DECREASE NOTABLY AFTER SUNSET...AND
WILL ALLOW TEMPERATURES TO FALL INTO THE 40S OVERNIGHT. COOL AND
DRY HIGH PRESSURE WILL THEN PREVAIL ON SUNDAY AS THE GREAT LAKES
TROUGH DIGS TOWARD THE EAST COAST. SUNDAY HIGHS WILL BE RIGHT
AROUND NORMAL...AND GENERALLY RANGE FROM 70 TO 75 DEGREES.
MID LEVEL RIDGING WILL ARRIVE INTO THE NORTH CENTRAL CONUS FOR
MONDAY...AND SOUTHERLY LOW LEVEL FLOW WILL DEVELOP AS A TROUGH
STRENGTHENS OVER THE NORTHERN/CENTRAL PLAINS. BY MONDAY
AFTERNOON...SUSTAINED WINDS OF 15 TO 25 MPH...WITH GUSTS INTO THE
30S APPEAR LIKELY OVER WEST/SOUTH CENTRAL MN. ALTHOUGH MOISTURE WILL
BE SLOWLY INCREASING...DEWPOINTS WILL LIKELY ONLY BE IN THE 45 TO 50
DEGREE RANGE. THEREFORE...THE COMBINATION OF STRONG
WINDS...RELATIVELY LOW HUMIDITY VALUES...AND DRY FUELS...WILL
CONTINUE TO SET THE STAGE FOR ENHANCED FIRE DANGER ON MONDAY
AFTERNOON/EVE AND POSSIBLY TUESDAY. /SEE THE FIRE WEATHER DISCUSSION
BELOW FOR MORE INFORMATION/.
TUESDAY WILL BE QUITE WARM ACROSS CENTRAL AND SOUTH CENTRAL MN AS
THE THERMAL RIDGE NOSES INTO THE AREA WITH THE ADVANCING FRONT.
HIGHS AROUND OR EVEN ABOVE 90 DEGREES APPEAR LIKELY ACROSS THE
HEART OF THE CWA. REALLY APPEARS AS IF THE FRONT WILL COME
THROUGH DRY...WITH CHANCE POPS HOLDING OFF UNTIL WEDNESDAY AS
REINFORCING MOISTURE AND DYNAMICS WITH A SHORTWAVE EJECTING
NORTHEAST FROM THE FOUR CORNERS REGION ARRIVE. SHOWER/TS POTENTIAL
APPEARS THE HIGHEST OVER SOUTHERN MN INTO WEST CENTRAL WI.
ON THURSDAY...A NORTHERN STREAM WAVE WILL BRING A REINFORCING SHOT
OF MORE SEASONAL AIR INTO THE UPPER MIDWEST. THURSDAY/FRIDAY HIGHS
WILL TOP OUT IN THE UPPER 60S AND LOWER 70S...AND LOWS WILL DIP
INTO THE 40S.
MID LEVEL RIDGING WILL BUILD BACK INTO THE CENTRAL UNITED STATES
FOR THE WEEKEND OF THE 15TH...AND YIELD ANOTHER RETURN TO DRY
WEATHER WITH ABOVE NORMAL TEMPERATURES.
&&
.AVIATION... /18Z TAF ISSUANCE/
STRONG COLD FRONT STILL ON SCHEDULE...DROPPING INTO CENTRAL MN NOW
AND EXITING SOUTHERN MN AFTER 23Z. SHRA ASSOCIATED SHOULD BE LIMITED
TO WC WI...WITH ISOLD TSRA PSBL. CONTINUED THE TREND OF VCSH AT
KRNH AND KEAU...WITH VCTS PSBL AT KEAU...FOR A COUPLE HOURS THIS
AFTERNOON WITH FROPA. STRONG NW WINDS DEVELOPING BEHIND FRONT WITH
35 KNOT GUSTS POSSIBLE MOST AREAS. SHOULD SEE GUSTINESS NED 03Z-04Z
MOST AREAS. QUESTION REMAINS AS TO EXTENT OF POSSIBLE MVFR CEILINGS
OVER EASTERN AREAS DURING THE NIGHT. THE 12Z RAP WAS MOST
PESSIMISTIC WITH LOWER CLOUDS AFFECTING KMSP EAST OVERNIGHT. WILL
LIMIT TO SCT040 OVER EASTERN MN AND MENTION CEILINGS DOWN TO 3500
FEET INTO WI OVERNIGHT FOR NOW. SUBSIDENCE WILL BE STRONG BEHIND
SYSTEM BUT NAM CONTINUES TO INDICATE SOME FAIRLY HIGH LOWER LEVEL RH
AROUND. SUNDAY SHOULD BE LESS EVENTFUL WITH LIGHTER NORTH WINDS AS
SURFACE HIGH DROPS SOUTH. MAYBE SOME CUMULUS INTO THE AFTERNOON OVER
EASTERN AREAS...BUT SHOULD DISSIPATE LATE BY LATE AFTERNOON.
KMSP...SOME CLOUDS AROUND WITH FROPA THIS AFTERNOON. MAY LINGER AS
CAA STRATOCUMULUS INTO THE EVENING. WILL LEAVE AS SCT FOR NOW.
SOME INDICATION OF LOWER MVFR CEILING DEVELOPING...BUT MAINLY TO THE
EAST OF THE AREA. STRONG NORTHWEST WINDS WITH FROPA WILL DISSIPATE
AFTER SUNSET. LIGHT NORTH WINDS THEN INTO SUNDAY WITH PERHAPS A FEW
CUMULUS INTO THE AFTERNOON.
/OUTLOOK FOR KMSP/
.MONDAY...VFR. WINDS S 15 TO 20 KTS WITH GUSTS TO 30 KTS.
.TUESDAY...VFR. WINDS SSW 15 TO 20 KTS WITH GUSTS TO 25 KTS.
.WEDNESDAY...MAINLY VFR WITH A CHC OF SHRA/TSRA. WINDS NW 7 KTS.
&&
.FIRE WEATHER.../ISSUED 320 PM CDT SAT SEP 8/
THERE IS A HEIGHTENED FIRE DANGER ON MONDAY AND TUESDAY AHEAD OF A
DEVELOPING LOW PRESSURE SYSTEM OVER THE NORTHERN PLAINS. SOUTHERLY
WINDS WILL INCREASE TO 20 TO 25 MPH WITH GUSTS TO 30 MPH AHEAD OF
THIS SYSTEM ON MONDAY...AS MOSTLY SUNNY SKIES ALLOW FOR
TEMPERATURES TO WARM INTO THE LOW TO MID 80S FROM WEST INTO SOUTH
CENTRAL MN. THE WARM TEMPERATURES WILL COMBINE WITH RELATIVELY LOW
DEWPOINTS IN THE MID 40S TO YIELD AFTERNOON HUMIDITY VALUES IN THE
LOW TO MID 20S. THE DRY VEGETATION AND FUELS IN DROUGHT AREAS OF
WEST AND SOUTH CENTRAL MN...COMBINED WITH THE EXPECTED WEATHER
CONDITIONS...WILL LEAD TO ELEVATED FIRE DANGER ON MONDAY AFTERNOON
AND EVENING. THEREFORE...A FIRE WEATHER WATCH HAS BEEN ISSUED FOR
MUCH OF WEST CENTRAL...SOUTHWEST...AND SOUTH CENTRAL MN ON MONDAY.
THE FIRE DANGER CONDITIONS MAY EXTEND THROUGH TUESDAY DEPENDING ON
THE TIMING WITH THE APPROACHING FRONTAL BOUNDARY. STAY TUNED TO
FUTURE FIRE WEATHER PRODUCTS AND DISCUSSIONS FOR UPDATED THINKING.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING
FOR BLUE EARTH-BROWN-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-
KANDIYOHI-LAC QUI PARLE-MARTIN-NICOLLET-POPE-REDWOOD-
RENVILLE-SIBLEY-STEVENS-SWIFT-WASECA-WATONWAN-YELLOW
MEDICINE.
WI...NONE.
&&
$$
LS/DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1225 PM CDT SAT SEP 8 2012
.AVIATION... /18Z TAF ISSUANCE/
STRONG COLD FRONT STILL ON SCHEDULE...DROPPING INTO CENTRAL MN NOW
AND EXITING SOUTHERN MN AFTER 23Z. SHRA ASSOCIATED SHOULD BE LIMITED
TO WC WI...WITH ISOLD TSRA PSBL. CONTINUED THE TREND OF VCSH AT
KRNH AND KEAU...WITH VCTS PSBL AT KEAU...FOR A COUPLE HOURS THIS
AFTERNOON WITH FROPA. STRONG NW WINDS DEVELOPING BEHIND FRONT WITH
35 KNOT GUSTS POSSIBLE MOST AREAS. SHOULD SEE GUSTINESS NED 03Z-04Z
MOST AREAS. QUESTION REMAINS AS TO EXTENT OF POSSIBLE MVFR CEILINGS
OVER EASTERN AREAS DURING THE NIGHT. THE 12Z RAP WAS MOST
PESSIMISTIC WITH LOWER CLOUDS AFFECTING KMSP EAST OVERNIGHT. WILL
LIMIT TO SCT040 OVER EASTERN MN AND MENTION CEILINGS DOWN TO 3500
FEET INTO WI OVERNIGHT FOR NOW. SUBSIDENCE WILL BE STRONG BEHIND
SYSTEM BUT NAM CONTINUES TO INDICATE SOME FAIRLY HIGH LOWER LEVEL RH
AROUND. SUNDAY SHOULD BE LESS EVENTFUL WITH LIGHTER NORTH WINDS AS
SURFACE HIGH DROPS SOUTH. MAYBE SOME CUMULUS INTO THE AFTERNOON OVER
EASTERN AREAS...BUT SHOULD DISSIPATE LATE BY LATE AFTERNOON.
KMSP...SOME CLOUDS AROUND WITH FROPA THIS AFTERNOON. MAY LINGER AS
CAA STRATOCUMULUS INTO THE EVENING. WILL LEAVE AS SCT FOR NOW.
SOME INDICATION OF LOWER MVFR CEILING DEVELOPING...BUT MAINLY TO THE
EAST OF THE AREA. STRONG NORTHWEST WINDS WITH FROPA WILL DISSIPATE
AFTER SUNSET. LIGHT NORTH WINDS THEN INTO SUNDAY WITH PERHAPS A FEW
CUMULUS INTO THE AFTERNOON.
/OUTLOOK FOR KMSP/
.MONDAY...VFR. WINDS S 15 TO 20 KTS WITH GUSTS TO 30 KTS.
.TUESDAY...VFR. WINDS SSW 15 TO 20 KTS WITH GUSTS TO 25 KTS.
.WEDNESDAY...MAINLY VFR WITH A CHC OF SHRA/TSRA. WINDS NW 7 KTS.
&&
.DISCUSSION... /ISSUED 248 AM CDT SAT SEP 8 2012/
A STRONG SHRTWV EARLY THIS MORNING WAS EVIDENT ON THE LATEST WV
IMAGERY JUST NORTH OF WINNIPEG. MODELS HAVE SLOWLY COME AROUND TO
A MORE SIGNIFICANT SYSTEM AFFECTING THE UPPER MIDWEST STARTING LATE
THIS MORNING...AND LASTING THRU EARLY THIS EVENING.
TWO FORECAST CONCERNS ARE ASSOCIATED WITH THIS SYSTEM TODAY. ONE
IS THE QUICK MOVEMENT WHICH MAY ALLOW FOR TEMPS ACROSS CENTRAL MN
TO MAX OUT BY LATE MORNING AS CURRENT TIMING OF THIS SHRTWV HAS IT
MOVING INTO KAXN BY 16Z. ALTHOUGH THERE SHOULD BE A FAIR AMT OF
SUNSHINE ACROSS WC/CENTRAL MN BEFORE THIS SYSTEM MOVES IN...CLDS
SHOULD QUICKLY INCREASE...ESPECIALLY EAST OF AXN WHICH MAY ALLOW
FOR TEMPS TO HOLD STEADY OR FALL IN CENTRAL/EC MN DURING THE AFTN.
WC MN WILL HAVE LITTLE OR NO CLD CVR ALONG WITH A LONGER TIME FOR
HEATING BEFORE THIS FRONT MOVES THRU. SO...WC/SW MN MAY RISE TO
NEAR 80 BEFORE LEVELING OFF BY THE EARLY AFTN. ACROSS EC MN AND WI
WC...STRONG LIFT AND AMPLE MOISTURE WILL ALLOW FOR SHRA TO
DEVELOP...WITH THE BEST COVERAGE IN WC WI WHERE LIKELY POPS SEEM
REASONABLE BY 18-21Z.
DUE TO THE SPEED OF THIS SYSTEM...THE OPPORTUNITY OF SHRA WILL BE
SHORT LIVED AS MOST OF THE LIFT WILL DEPART THE AREA BY 00Z/09.
WINDS WILL INCREASE SIGNIFICANTLY BY NOON...WITH GUSTS OVER 30 MPH
LIKELY IN WC MN BY NOON. SOME FIRE WEATHER CONCERNS ARE
EVIDENT...ESPECIALLY IN WC/SW MN. WILL HIGHLIGHT MORNING HWO ON
THIS SCENARIO...AND LET THE DAY SHIFT CALL FIRE WEATHER PERSONAL
FOR A POSSIBLE WARNING IF NECESSARY. FIRE WEATHER CONCERNS WILL BE
MORE EVIDENT ON MONDAY AS A STRONG SW WIND DEVELOPS ALONG THE
LEADING EDGE OF A STRONGER SYSTEM AFFECTING THE UPPER MIDWEST BY
TUESDAY AFTN/WED.
THERE ARE SEVERAL FACTORS LEADING TO A HIGH FIRE DANGER FOR
MONDAY AS THE COMBINATION OF DRY VEGETATION AND STRONG MIXING FROM
FULL SUNSHINE LEADING TO STRONG SW WINDS...AND THE ADDED AFFECT OF
THE DROUGHT CONDITIONS HAVE WORSEN IN THIS AREA. WILL AGAIN
HIGHLIGHT AREAS OF CONCERN IN THE MORNING HWO.
THERE IS A SMALL OPPORTUNITY OF SHRA/TSRA WED/WED AFTN IN SC MN AS
THE FRONT MAY SLOW ALLOWING FOR DEEPER MOISTURE TO RETURN FOR THE
UPPER MIDWEST. AS FOR TEMPS...80S AND A FEW LOW 90S ARE NOT OUT
OF THE QUESTION FOR PORTIONS OF THE FA MONDAY AND AGAIN TUE. AFT
WED...MORE SEASONABLE TEMPS WILL RETURN WITH A STRONGER SIGNAL OF A
STRONG COLD FRONT MOVING THRU THE UPPER MIDWEST AFT THE 15TH OF
SEPT. THE LATEST EC/GFS HAVE HINTED OF A LARGE RIDGE DEVELOPING
ACROSS THE PACIFIC NW...INTO WESTERN CANADA. THIS RIDGE WILL ALLOW
OR CONTRIBUTE TO A LONG WAVE TROUGH DEVELOPING ACROSS CENTRAL
CANADA AND INTO THE GREAT LAKES REGION. THIS WILL ALLOW FOR N/NW
FLOW TO DEVELOP AND THE POSSIBILITY OF MUCH COLDER AIR MASSES TO
FILTER SOUTHWARD INTO THE UPPER MIDWEST.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JLT/DE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
549 PM CDT SAT SEP 8 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT THROUGH SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A VIGOROUS AND
COMPACT SHORTWAVE TROUGH MOVING SOUTHEAST INTO NORTHWEST WISCONSIN
EARLY THIS AFTERNOON. LEADING BAND OF SHOWERS IS DIVING ACROSS
NORTH-CENTRAL WISCONSIN...WHILE ADDITIONAL SHOWER ACTIVITY EXISTS
ACROSS THE ARROWHEAD OF MINNESOTA IN THE WRAP-AROUND REGION OF THE
SYSTEM. A REINFORCEMENT OF COOLER AIR IS FOLLOWING IN THE WAKE OF
THE SHORTWAVE WHERE 850MB TEMPS ARE FALLING BELOW 4C OVER NORTHERN
MINNESOTA AND WESTERN ONTARIO. PRECIP TRENDS ARE THE MAIN FORECAST
CONCERN OVER THE NEXT 24 HOURS.
TONIGHT...COMPACT YET POTENT SHORTWAVE TROUGH WILL CONTINUE TO DIVE
SE AND EXIT THE STATE BY MID-EVENING. LOW LEVEL TROUGH BENEATH
PLENTY OF MID-LEVEL MOISTURE WILL KEEP LIKELY TO DEFINITE SHOWERS
AROUND OVER CENTRAL AND NORTHEAST WISCONSIN FOR THE FIRST HALF OF
THE EVENING. SOME SHOWERS BEHIND THE SYSTEM AS WELL OVER THE
ARROWHEAD SO DECIDED TO KEEP A LOW END CHANCE OF SHOWERS OVER N-C
WISCONSIN. THEREAFTER...SHOULD SEE SHOWERS EXIT EAST-CENTRAL
WISCONSIN BY LATE EVENING WHILE DELTA T/S OVER WESTERN LAKE SUPERIOR
INCREASE TO 14-15C IN NORTHERLY FLOW. WITH RICH ENOUGH MOISTURE IN
THE 850-700MB LAYER...LAKE EFFECT SHOWERS LOOK TO BE A GOOD BET TO
DEVELOP LATER THIS EVENING AND OVERNIGHT. AS A RESULT...CLOUDS WILL
BE SLOWER TO DEPART OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THAN
FARTHER EAST WHERE MODELS SHOW DRY AIR FROM EASTERN ONTARIO SURGING
SOUTH OVER NORTHEAST WISCONSIN. TEMPS FALLING INTO THE 40S
NORTHWEST OF THE FOX VALLEY...AND INTO THE LOWER 50S ELSEWHERE.
SUNDAY...CANADIAN HIGH PRESSURE WILL BE BUILDING INTO THE STATE
THROUGH THE DAY. NORTHERLY FLOW AHEAD OF THE SURFACE HIGH WILL
CONTINUE TO SEND LAKE EFFECT CLOUDS AND SPOTTY SHOWERS INTO
NORTH-CENTRAL WISCONSIN THROUGH THE MORNING. ELSEWHERE...DIURNAL CU
WILL BE BUILDING BY MIDDAY WHICH WILL LEAD TO A PARTLY CLOUDY DAY.
HIGHS RANGING FROM THE MID 60S NORTH TO LOW 70S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...TEMPERATURES
THROUGHOUT THE PERIOD...AND PCPN CHANCES FOR THE MID TO LATE PART
OF THE WORK WEEK...ARE THE MAIN FCST CONCERNS.
COOL CANADIAN HIGH PRESSURE WILL RESIDE OVER THE REGION AT THE
BEGINNING OF THE PERIOD. COULD SEE SOME PATCHY FROST OVER PARTS
OF NORTHERN WI...WITH MIN TEMPS EXPECTED TO DROP INTO THE MID TO
UPPER 30S IN THE TYPICAL COLD SPOTS.
RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL RESULT IN A WARM-UP
ON MONDAY AND TUESDAY...WITH TEMPERATURES RISING TO WELL ABOVE
NORMAL LEVELS AGAIN BY TUESDAY. BREEZY CONDITIONS WILL ALSO DEVELOP
ON TUESDAY...AS THE PRESSURE GRADIENT STRENGTHENS BETWEEN THE
DEPARTING HIGH AND A COLD FRONT MOVG INTO MINNESOTA.
THE COLD FRONT WILL EDGE TOWARD NC WI LATE TUESDAY NIGHT...THEN
MOVE SLOWLY SE THROUGH THE FORECAST AREA ON WEDS/WEDS NGT/THU.
WITH AN UPPER TROF AND THE RRQ OF AN UPPER LEVEL JET LAGGING TO
THE WEST OF THE FRONT...PCPN IS EXPECTED TO BE POST-FRONTAL. WILL
HAVE CHC POPS OVER NC WI ON WEDS...ACROSS MOST OF THE CWA ON WEDS
NGT...AND CONTINUING OVER AT LEAST OUR SE COUNTIES ON THU/THU NGT.
THE 12Z ECMWF HAS CAST SOME DOUBT ON THIS SCENARIO...AS IT
REDEVELOPS PCPN ACROSS MOST OF WISCONSIN FROM THURSDAY NIGHT
THROUGH FRIDAY NIGHT...AS IT LIFTS A SFC WAVE NEWD ALONG THE
STALLED FRONTAL BOUNDARY. THIS CANNOT BE RULED OUT...GIVEN THE
FAIRLY POTENT UPPER TROF/JET STREAK PREDICTED BY THE MODELS. WILL
NEED TO WATCH THE TRENDS ON THIS OVER THE NEXT FEW DAYS.
ANOTHER COOLER CANADIAN AIR MASS WILL BUILD INTO THE REGION IN
THE WAKE OF THE COLD FRONT...ALLOWING TEMPERATURES TO DROP TO
AROUND SEASONAL NORMALS FOR MID-SEPTEMBER.
&&
.AVIATION...AN UPPER LOW WITH SURFACE COLD FRONT WILL DROP OVER
EASTERN WISCONSIN THIS EVENING. BANDS OF SHOWERS WITH ISOLATED
STORMS WILL PRODUCE SCATTERED MVFR CIGS AND VSBYS MAINLY THIS
EVENING. AS THE UPPER LOW DEPARTS TO THE EAST LATER TONIGHT...VFR
CONDITIONS TO DOMINATE...WITH THE EXCEPTION OF PATCHY MVFR CIGS
OVER FAR NORTH CENTRAL WISCONSIN. DRIER AIR WILL FEED INTO THE
STATE SUNDAY TO CONTINUE THE VFR CONDITIONS.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
239 PM CDT SAT SEP 8 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A VIGOROUS AND
COMPACT SHORTWAVE TROUGH MOVING SOUTHEAST INTO NORTHWEST WISCONSIN
EARLY THIS AFTERNOON. LEADING BAND OF SHOWERS IS DIVING ACROSS
NORTH-CENTRAL WISCONSIN...WHILE ADDITIONAL SHOWER ACTIVITY EXISTS
ACROSS THE ARROWHEAD OF MINNESOTA IN THE WRAP-AROUND REGION OF THE
SYSTEM. A REINFORCEMENT OF COOLER AIR IS FOLLOWING IN THE WAKE OF
THE SHORTWAVE WHERE 850MB TEMPS ARE FALLING BELOW 4C OVER NORTHERN
MINNESOTA AND WESTERN ONTARIO. PRECIP TRENDS ARE THE MAIN FORECAST
CONCERN OVER THE NEXT 24 HOURS.
TONIGHT...COMPACT YET POTENT SHORTWAVE TROUGH WILL CONTINUE TO DIVE
SE AND EXIT THE STATE BY MID-EVENING. LOW LEVEL TROUGH BENEATH
PLENTY OF MID-LEVEL MOISTURE WILL KEEP LIKELY TO DEFINITE SHOWERS
AROUND OVER CENTRAL AND NORTHEAST WISCONSIN FOR THE FIRST HALF OF
THE EVENING. SOME SHOWERS BEHIND THE SYSTEM AS WELL OVER THE
ARROWHEAD SO DECIDED TO KEEP A LOW END CHANCE OF SHOWERS OVER N-C
WISCONSIN. THEREAFTER...SHOULD SEE SHOWERS EXIT EAST-CENTRAL
WISCONSIN BY LATE EVENING WHILE DELTA T/S OVER WESTERN LAKE SUPERIOR
INCREASE TO 14-15C IN NORTHERLY FLOW. WITH RICH ENOUGH MOISTURE IN
THE 850-700MB LAYER...LAKE EFFECT SHOWERS LOOK TO BE A GOOD BET TO
DEVELOP LATER THIS EVENING AND OVERNIGHT. AS A RESULT...CLOUDS WILL
BE SLOWER TO DEPART OVER CENTRAL AND NORTH-CENTRAL WISCONSIN THAN
FARTHER EAST WHERE MODELS SHOW DRY AIR FROM EASTERN ONTARIO SURGING
SOUTH OVER NORTHEAST WISCONSIN. TEMPS FALLING INTO THE 40S
NORTHWEST OF THE FOX VALLEY...AND INTO THE LOWER 50S ELSEWHERE.
SUNDAY...CANADIAN HIGH PRESSURE WILL BE BUILDING INTO THE STATE
THROUGH THE DAY. NORTHERLY FLOW AHEAD OF THE SURFACE HIGH WILL
CONTINUE TO SEND LAKE EFFECT CLOUDS AND SPOTTY SHOWERS INTO
NORTH-CENTRAL WISCONSIN THROUGH THE MORNING. ELSEWHERE...DIURNAL CU
WILL BE BUILDING BY MIDDAY WHICH WILL LEAD TO A PARTLY CLOUDY DAY.
HIGHS RANGING FROM THE MID 60S NORTH TO LOW 70S SOUTH.
.LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...TEMPERATURES
THROUGHOUT THE PERIOD...AND PCPN CHANCES FOR THE MID TO LATE PART
OF THE WORK WEEK...ARE THE MAIN FCST CONCERNS.
COOL CANADIAN HIGH PRESSURE WILL RESIDE OVER THE REGION AT THE
BEGINNING OF THE PERIOD. COULD SEE SOME PATCHY FROST OVER PARTS
OF NORTHERN WI...WITH MIN TEMPS EXPECTED TO DROP INTO THE MID TO
UPPER 30S IN THE TYPICAL COLD SPOTS.
RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL RESULT IN A WARM-UP
ON MONDAY AND TUESDAY...WITH TEMPERATURES RISING TO WELL ABOVE
NORMAL LEVELS AGAIN BY TUESDAY. BREEZY CONDITIONS WILL ALSO DEVELOP
ON TUESDAY...AS THE PRESSURE GRADIENT STRENGTHENS BETWEEN THE
DEPARTING HIGH AND A COLD FRONT MOVG INTO MINNESOTA.
THE COLD FRONT WILL EDGE TOWARD NC WI LATE TUESDAY NIGHT...THEN
MOVE SLOWLY SE THROUGH THE FORECAST AREA ON WEDS/WEDS NGT/THU.
WITH AN UPPER TROF AND THE RRQ OF AN UPPER LEVEL JET LAGGING TO
THE WEST OF THE FRONT...PCPN IS EXPECTED TO BE POST-FRONTAL. WILL
HAVE CHC POPS OVER NC WI ON WEDS...ACROSS MOST OF THE CWA ON WEDS
NGT...AND CONTINUING OVER AT LEAST OUR SE COUNTIES ON THU/THU NGT.
THE 12Z ECMWF HAS CAST SOME DOUBT ON THIS SCENARIO...AS IT
REDEVELOPS PCPN ACROSS MOST OF WISCONSIN FROM THURSDAY NIGHT
THROUGH FRIDAY NIGHT...AS IT LIFTS A SFC WAVE NEWD ALONG THE
STALLED FRONTAL BOUNDARY. THIS CANNOT BE RULED OUT...GIVEN THE
FAIRLY POTENT UPPER TROF/JET STREAK PREDICTED BY THE MODELS. WILL
NEED TO WATCH THE TRENDS ON THIS OVER THE NEXT FEW DAYS.
ANOTHER COOLER CANADIAN AIR MASS WILL BUILD INTO THE REGION IN
THE WAKE OF THE COLD FRONT...ALLOWING TEMPERATURES TO DROP TO
AROUND SEASONAL NORMALS FOR MID-SEPTEMBER.
&&
.AVIATION...A COMPACT BUT DYNAMIC UPPER LEVEL DISTURBANCE WILL DROP
SOUTH ACROSS THE REGION THIS AFTERNOON. LIGHT TO MODERATE SHOWERS
WILL MOVE SOUTH-SOUTHEAST AHEAD OF THIS DISTURBANCE EARLY TO
MID-AFTERNOON OVER NORTH-CENTRAL AND CENTRAL WISCONSIN...AND MID TO
LATE AFTERNOON OVER NORTHEAST WISCONSIN AND THE FOX VALLEY. NOT OUT
OF THE QUESTION THAT COULD ALSO SEE A RUMBLE OF THUNDER AND MVFR
CIGS/VSBYS WITHIN THE HEAVIER SHOWERS. THE SHOWERS WILL BE DEPARTING
EARLY THIS EVENING BUT THINK SOME MVFR CIGS WILL STICK AROUND FOR
PARTS OF THE EVENING. EVENTUALLY THOUGH...MODELS PROJECT DRIER AIR
ARRIVING LATE THIS EVENING ONWARD FROM THE NORTH THAT WILL ERODE ANY
LOW CLOUD COVER...EXCEPT OVER FAR NORTH-CENTRAL WISCONSIN WHERE SCT
LAKE EFFECT RAIN SHOWERS MAY OCCUR. THEREAFTER...LOOK FOR SCT TO BKN
CU TO DEVELOP BY LATE MORNING TOMORROW WITH DAYTIME HEATING.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KIECKBUSCH