Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/04/13
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
440 PM MST TUE SEP 3 2013
.UPDATE...UPDATED AVIATION DISCUSSION...
&&
.SYNOPSIS...
A WEATHER DISTURBANCE WILL LEAD TO A SOMEWHAT ELEVATED CHANCE OF
SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. THE BEST CHANCE OF
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN OF SOUTH CENTRAL
ARIZONA. THE REMAINDER OF THE WORK WEEK WILL HAVE ONLY SLIGHT
CHANCES FOR THUNDERSTORMS ALONG WITH SOMEWHAT ABOVE NORMAL
TEMPERATURES. SATURDAY THROUGH MONDAY...STORM CHANCES WILL BE
CONFINED EAST OF THE LOWER COLORADO RIVER VALLEY.
&&
.DISCUSSION...
REST OF TODAY AND TONIGHT...
KIWA RADAR DATA COMMS LINE NOW REPAIRED. STORM ACTIVITY SO FAR THIS
AFTERNOON HAS ESSENTIALLY BEEN OVER EASTERN ARIZONA...MAINLY IN A
NORTH-SOUTH CORRIDOR FROM THE WESTERN MOGOLLON RIM DOWN THROUGH
EASTERN PIMA COUNTY. THIS CORRESPONDS WELL WITH NAM FORECASTS OF
MOST FAVORABLE AREA...DRIVEN BY UPPER DIVERGENCE AHEAD OF
APPROACHING SHORT WAVE FROM THE EAST...AS WELL AS TIMING. WITH DEW
POINTS IN THE MID 50S OVER THE LOWER DESERTS OF CENTRAL ARIZONA...IT
WILL BE DIFFICULT TO GET A LOT OF STORMS TO SURVIVE OFF THE HIGHER
TERRAIN. EARLIER RUNS OF THE HRRR MODEL LOOK TO BE OVERDONE...SO
FAR...AND NOW LATEST RUN IS LESS ENTHUSIASTIC ABOUT STORM COVERAGE.
HOWEVER...WIND PRODUCTION SHOULD BE EFFICIENT AND THUS ADDED MENTION
OF BLOWING DUST TO THE CENTRAL DESERT ZONES...INCLUDING PHOENIX.
STILL ENOUGH FORCING AND UPSTREAM STORMS TO KEEP CHANCE WORDING...AS
OPPOSED TO SLIGHT CHANCE. FOR OUR WESTERN AREAS...WHERE MOISTURE IS
RICHER...ANTICIPATE LESS ACTION THAN LAST NIGHT GIVEN THAT THE
REMNANT WAVE FROM FORMER T.S. KIKO HAS PASSED. HOWEVER...HIGHER
TERRAIN OF SAN DIEGO AND WESTERN RIVERSIDE COUNTIES AS WELL AS
MOUNTAINS OF NORTHERN BAJA DO HAVE SOME STORMS WHICH CAN SEND
OUTFLOWS TO TRIGGER NEW STORMS. THE WAVE WILL BE MOVING SLOW ENOUGH
THAT THERE COULD BE SPOTTY LINGERING SHOWER ACTIVITY OVERNIGHT.
WEDNESDAY THROUGH MONDAY...
THE SHORT WAVE MAY KEEP WEAK ACTIVITY GOING OVER SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA WEDNESDAY BUT CAPE WILL BE QUIET
MODEST. BOTH NAM AND GFS SHOW A DECLINE OF MOISTURE...EVIDENT IN
1000-500 MB MEAN MIXING RATIOS...BUT THE GFS IS MORE AGGRESSIVE THAN
THE NAM. THUS ONLY SLIGHT CHANCES WILL PREVAIL...DESPITE A
CLIMATOLOGICALLY FAVORABLE WIND FLOW PATTERN. SHORT WAVES EMANATING
FROM MEXICO WILL BE SOMETHING OF AN X FACTOR...MOST NOTABLY FRIDAY.
OVER THE WEEKEND...GFS DEPICTS THE PERSISTENT TROUGHING NEAR THE
WEST COAST TO SHIFT INLAND BUT THE RIDGE AXIS STAYS JUST FAR ENOUGH
NORTH TO KEEP MOISTURE FROM GOING AWAY ENTIRELY. THE ECWMF BRINGS IN
A BUNCH OF MOISTURE ASSOCIATED WITH TROPICAL REMNANTS. WAY TOO EARLY
TO BUY OFF ON THE LATTER SCENARIO BUT WILL HOLD ON TO LOW GRADE
MONSOON WITH POPS BEING CONFINED TO AREAS EAST OF THE LOWER COLORADO
RIVER VALLEY SATURDAY THROUGH MONDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
CONVECTION HAS STRUGGLED TO MAKE IT OFF THE HIGHER TERRAIN SO
FAR...ALTHOUGH OUTFLOW WINDS WILL KICK THE WINDS AROUND OUT OF THE
EAST RELATIVELY EARLY THIS EVENING. EXPECT EAST WINDS AROUND 5-10KTS
BY 01Z AT ALL SITES. AS FOR PRECIP CHANCES...LOOKS LIKE THE BEST
CHANCES WILL BE KIWA/KSDL AND EVEN THAT MAY BE A STRETCH. WILL ONLY
MENTION VCSH AT THOSE SITES FOR A FEW HOURS AND KEEP PRECIP OUT OF
KPHX. HIGH CLOUDS MOVING ACROSS THE AREA LIKELY INHIBITING
CONVECTION VALLEY-WIDE.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
QUIET WEATHER AT THE MOMENT...BUT THE BIG QUESTION IS IF THE
CONVECTION PRESENTLY ACROSS PIMA COUNTY WILL MAKE ITS WAY UP THE
RIVER AND INTO IMPERIAL AND/OR BLYTHE. I WILL THROW IN HIGH CLOUDS
AT BOTH SITES AND A MENTION OF VCSH AT IMPERIAL...OTHERWISE I AM
EXPECTING THINGS TO BE QUIET AT BOTH SE CA SITES.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH TUESDAY...
DRIER AIR ACROSS THE REGION WILL LIKELY KEEP MOST THUNDERSTORM
ACTIVITY CONFINED TO THE HIGHER TERRAIN EAST OF PHOENIX...WITH JUST
SOME ISOLATED STORMS POSSIBLE INTO THE DESERTS EACH AFTERNOON AND
EVENING. HUMIDITIES EACH AFTERNOON WILL DROP INTO THE UPPER TEENS TO
MIDDLE TWENTIES PERCENT RANGE ACROSS THE LOWER DESERTS...WITH GOOD
OVERNIGHT RECOVERY ANTICIPATED. OUTSIDE OF THUNDERSTORMS...WINDS
WILL FAVOR THE TYPICAL DIURNAL UPSLOPE/DOWNVALLEY PATTERNS. MEDIUM
RANGE FORECAST MODELS BEGIN TO DIVERGE BY THE LATE WEEKEND WITH
REGARDS TO THE UPPER LEVEL PATTERN AND AMOUNT OF MONSOON MOISTURE
ACROSS THE REGION. WILL CONTINUE TO MONITOR THE EVOLUTION OF THE
PATTERN AND ANY POTENTIAL FIRE WEATHER IMPACTS OVER THE NEXT FEW
PERIODS. WITH THE DEEP MOISTURE FORECAST TO MOVE INTO THE REGION BY
ONE MODEL...HUMIDITIES AND RAINFALL CHANCES COULD SEE A HEALTHY
BOOST BY THE LATE WEEKEND.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
AVIATION...LEINS
FIRE WEATHER...NOLTE/KUHLMAN
AREA FORECAST DISCUSSION
NWS TUCSON AZ
245 PM MST MON SEP 2 2013
.SYNOPSIS...SUFFICIENT MOISTURE WILL KEEP ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST ARIZONA THIS WEEK.
AFTERNOON HIGH TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL.
&&
.DISCUSSION...KEMX WSR-88D DETECTED ISOLATED 35-50 DBZ ECHOES ON THE
GALIURO/PINALENO MOUNTAINS IN SWRN GRAHAM COUNTY AND JUST WEST OF
THE CHIRICAHUA MOUNTAINS IN FAR ERN COCHISE COUNTY AT 2140Z. THE
REST OF SE AZ WAS VOID OF PRECIP ECHOES AT THIS TIME. THE THICKER
CLOUDS ASSOCIATED WITH REMNANT MCV WERE MOVING NWWD ACROSS PINAL/ERN
PIMA COUNTIES...WITH OTHER CUMULOFORM CLOUDS ON MOST OF THE
MOUNTAINS OF GREENLEE/GRAHAM/COCHISE COUNTIES.
GIVEN THE PASSAGE OF THE MCV EARLIER TODAY...FORECAST CONFIDENCE IS
FAIRLY LOW THRU THIS EVENING. GIVEN THE RECENT CELL DEVELOPMENT
ADJACENT THE GALIURO/PINALENO/CHIRICAHUA MOUNTAINS...APPEARS THAT
SEVERAL RUC HRRR SOLUTIONS MAY HAVE THE BEST HANDLE REGARDING
CONVECTIVE DEVELOPMENT AND PROGRESSION INTO THIS EVENING.
THUS...DURING THE NEXT 1-2 HOURS OR SO...SHOWERS/TSTMS SHOULD
DEVELOP ACROSS THE HIGHER TERRAIN OF GREENLEE/GRAHAM/COCHISE
COUNTIES. SHOWERS/TSTMS MAY THEN MOVE AS FAR WEST AS THE TUCSON
METRO AREA BY AROUND SUNSET. MOSTLY DRY CONDITIONS SHOULD OCCUR
ACROSS WRN/CENTRAL PIMA COUNTY INTO THIS EVENING. HAVE OPTED FOR DRY
CONDITIONS LATE TONIGHT EXCEPT FOR A SLIGHT CHANCE OF SHOWERS/TSTMS
MAINLY NEAR THE NEW MEXICO BORDER.
TUE-TUE NIGHT...
HAVE MAINTAINED SCATTERED SHOWERS/TSTMS ACROSS MUCH OF SE AZ TUE
AFTERNOON/EVENING. HOWEVER...HAVE NOTED THAT THE GFS/ECMWF HAVE
TRENDED FURTHER SOUTH WITH THE WESTWARD PROGRESSION OF AN INVERTED
TROUGH VERSUS PREVIOUS SOLUTIONS. THUS...THE ACTUAL COVERAGE MAY BE
LESS THAN THE CURRENT OFFICIAL FORECAST DEPICTS.
WED-MON...
UPPER HIGH IS PROGGED TO BE GENERALLY CENTERED OVER THE CENTRAL
CONUS PLAINS. MEANWHILE...A DEEP UPPER LOW CENTERED INITIALLY NEAR
THE PACIFIC NW COAST WILL EVENTUALLY WEAKEN AND MOVE EWD ACROSS THE
NRN ROCKIES BY EARLY NEXT WEEK. MOISTURE APPEARS TO BE SUFFICIENT TO
MAINTAIN ISOLATED-SCATTERED AFTERNOON AND EVENING SHOWERS/TSTMS.
HIGH TEMPS THIS WEEK ARE FORECAST TO AVERAGE ABOUT 2-5 DEGS F OR SO
ABOVE CLIMO.
&&
.AVIATION...ISOLD-SCT TSRA/SHRA THRU THIS EVENING AND AGAIN TUESDAY
AFTERNOON. THE BULK OF THIS ACTIVITY SHOULD OCCUR EAST OF KTUS TO
THE NEW MEXICO BORDER. DRY CONDITIONS ARE EXPECTED ACROSS MUCH OF
THE AREA LATE TONIGHT AND TUESDAY MORNING. OTHERWISE...AFTERNOON AND
EVENING CLOUD DECKS WILL BE NEAR 7-11K FT AGL THEN MOSTLY ABOVE 12K
FT AGL LATE TONIGHT AND EARLY TUESDAY MORNING. SURFACE WIND WILL
GENERALLY BE LESS THAN 10 KTS THRU TUESDAY AFTERNOON OR 04/00Z.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS INTO NEXT WEEKEND. STRONG...GUSTY AND ERRATIC WINDS
WILL OCCUR WITH THE STRONGER THUNDERSTORMS. OTHERWISE...HIGH
PRESSURE CENTERED NORTH AND EAST OF THE AREA WILL PROVIDE A SURFACE
WIND FLOW REGIME GENERALLY FROM THE EAST TO SOUTHEAST DURING MUCH OF
THIS WEEK. DAYTIME TEMPERATURES WILL REMAIN ABOVE NORMAL THIS WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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BF
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
150 PM MST MON SEP 2 2013
.UPDATE...TO AVIATION AND FIRE WEATHER DISCUSSIONS...
.SYNOPSIS...
LINGERING MONSOON MOISTURE...ALONG WITH WARMER AFTERNOONS...AND A
FEW HARD TO TIME WEATHER DISTURBANCES WILL RESULT IN A SLIGHT CHANCE
OF AFTERNOON AND EVENING THUNDERSTORMS REGION WIDE THIS WEEK.
&&
.DISCUSSION...
A VORT MAX...CURRENTLY CENTERED NEAR BLYTHE HELPED TRIGGER
CONSIDERABLE STORM ACTIVITY OVER SONORA LAST NIGHT WHICH LEAD TO AN
MCV NEAR THE MEXICO BORDER. THIS FEATURE KEPT CONVECTION GOING AND
MOVED INTO PIMA COUNTY. GUSTY WINDS FROM THOSE STORMS HAVE MADE IT
INTO THE PHOENIX AREA ALREADY. SURPRISINGLY DUSTY GIVEN THE
UNDERWHELMING STRENGTH OF THE WINDS AND LACK OF VIS REDUCTION AT
CGZ. DUST WILL IMPROVE SHORTLY. MADE SOME UPDATES TO THE FORECASTS
EARLIER TO INTRODUCE SLIGHT CHANCE POPS OVER PORTIONS OF
YUMA...SOUTHWEST MARICOPA...AND WESTERN PINAL COUNTIES FOR THIS
MORNING. ALSO NUDGED UP POPS A BIT FOR THIS AFTERNOON...INCLUDING
LOW END SLIGHT CHANCES FOR THE PHOENIX AREA. STORM ACTIVITY THAT HAD
BE CLOSER TO THE CENTER OF THE MCV HAVE WEAKENED QUITE A BIT BUT NEW
STORMS HAVE DEVELOPED ON THE WESTERN PERIPHERY OF IT AS OF THIS
WRITING. HRRR MODEL REFLECTS THIS FEATURE BUT HAS BEEN INDICATING
SOUTHWEST MARICOPA COUNTY GETTING MORE INVOLVED THAN IT HAS. IT GOES
ON TO DEVELOP A GOOD DEAL OF STORMS OVER SOUTHWEST ARIZONA AS WELL
AS STORMS ALONG A THE SPINE OF HIGHEST TERRAIN IN OUR ZONE 24.
NEITHER OF THE 06Z RUNS OF THE NMM6KM NOR OUR LOCAL WRF DEPICTED ANY
OF THE CONVECTION THIS MORNING. 12Z SOUNDINGS INDICATE GOOD MIXED
LAYER CAPE...ESPECIALLY TWC. HOWEVER...THIS VERY FEATURE MAY WIND UP
INHIBITING STORM COVERAGE OVER THE SOUTH-CENTRAL ARIZONA DESERTS
LATER TODAY DUE TO BOUNDARY LAYER STABILIZATION THAT OCCURRED
UPSTREAM FROM THE RAIN COOLED AIR. FOR SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA...THE AFOREMENTIONED DISTURBANCE WHICH
INITIATED THINGS TODAY HAS NOT HAD MUCH IMPACT SO FAR.
HOWEVER...THERE ARE MORE DISTURBANCES TO COME ASSOCIATED WITH THE
REMNANTS OF KIKO WHICH MAY PROVIDE A LITTLE DYNAMICAL NUDGE TO AID
IN STORM ACTIVITY. SO ABOVE NORMAL POPS CONTINUE THERE. WILL
CONTINUE TO EVALUATE. MORE LATER.
&&
.PREVIOUS DISCUSSION...ISSUED AT 300 AM...
TODAY AND TUESDAY...
MOST OF THE CONVECTIVE POTENTIAL MONDAY WILL LIKELY BE FOCUSED OVER
PORTIONS OF SOUTHEAST CA AND THE COLORADO RIVER VALLEY...AS
ACCELERATING UPPER LEVEL SOUTHERLY WINDS FLOW INTO AN INCREASING
JETMAX OVER EASTERN NEVADA. IN OTHER WORDS...ENTRANCE REGION
DYNAMICS IS EXPECTED OVER SOUTHEAST CA. THE HIGHEST PRECIP
PROBABILITIES WILL BE IN THAT REGION. DITTO ON TUESDAY. THE
REMAINDER OF THE FORECAST AREA...SOUTHWEST AND SOUTH CENTRAL AZ WILL
BE DEVOID OF ANY UPPER LEVEL SUPPORT...THEREFORE A SLIGHT CHANCE OF
HEAT OF THE DAY SHOWERS AND THUNDERSTORMS WILL EXIST...WITH SOMEWHAT
HIGHER PROBABILITIES IN THE MOUNTAINS OF SOUTHERN GILA COUNTY.
ALSO ON TUESDAY...AN INVERTED TROF IS FORECAST TO MOVE INTO
SOUTHEAST AZ FROM WEST TEXAS BY EVENING. THEREFORE WE HAVE DECIDED
TO GO WITH A HIGHER PRECIP PROBABILITY OVER PORTIONS OF SOUTH
CENTRAL AZ...INCLUDING THE DESERTS AROUND PHOENIX AND CASA GRANDE.
MODELS FORECAST THE INVERTED TROF MAY ALSO SUPPORT A FEW NOCTURNAL
SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL AZ INTO WEDNESDAY
MORNING.
WEDNESDAY THROUGH SUNDAY...
IN THE AFTER-MATH OF THE ABOVE MENTIONED INVERTED TROF TUESDAY
AFTERNOON AND EVENING...DRIER AIR IS FORECAST TO SPREAD INTO EASTERN
AZ. BUT WITH WARMER AFTERNOONS...INSTABILITY TSTMS ARE STILL
POSSIBLE IN THE MOUNTAINS. A SLIGHT CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE ALSO FORECAST ON THE DESERTS AS MODELS HINT THAT A
FEW WEAK INVERTED TROFS WILL FLOW INTO THE REGION FROM MEXICO UNDER
SOUTHERLY FLOW ALOFT. THESE FEATURES WILL BE HARD TO TIME.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
AFTER THIS AFTERNOON/S THUNDERSTORM ACTIVITY THAT IS NOW MOVING
THROUGH THE GREATER PHX AREA...WHILE WILL LIKE PRODUCE GUSTY WINDS
AND BRIEF HEAVY DOWNPOURS...THERE IS STILL A CHANCE THAT MORE
THUNDERSTORMS...OR DUST STORMS COULD AFFECT THE TERMINALS THROUGH
THE EVENING HOURS...AND WILL HAVE VCTS IN THE TAFS TO REFLECT THIS
POSSIBILITY. OTHERWISE...SCT TO BKN MID-HIGH LEVEL CIGS WILL BE THE
RULE THROUGH THE TAF PERIOD. WINDS TO REMAIN MAINLY ON THE LIGHT
SIDE...OUTSIDE OF THUNDERSTORMS.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
KEEPING VCSH IN BOTH THE KBLH AND KIPL TAFS THROUGH THE EVENING
HOURS TO REFLECT THE CONTINUED DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS ACROSS THE DESERTS OF SW AZ AND SE CA. OTHERWISE...SCT
TO BKN MID-HIGH LEVEL CIGS WILL BE THE RULE THROUGH THE TAF PERIOD.
WINDS TO REMAIN MAINLY ON THE LIGHT SIDE...AND FOLLOW THE USUAL
DIURNAL TRENDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
DRIER AIR ACROSS THE REGION WILL LIKELY KEEP MOST THUNDERSTORM
ACTIVITY CONFINED TO THE HIGHER TERRAIN EAST OF PHOENIX...WITH JUST
SOME ISOLATED STORMS MOVING INTO THE DESERTS EACH AFTERNOON AND
EVENING. HUMIDITIES EACH AFTERNOON WILL DROP INTO THE 20 TO 30
PERCENT RANGE ACROSS THE LOWER DESERTS...WITH GOOD OVERNIGHT
RECOVERY ANTICIPATED. OUTSIDE OF THUNDERSTORMS...WINDS WILL FAVOR
THE TYPICAL DIURNAL UPSLOPE/DOWNVALLEY PATTERNS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...PERCHA
FIRE WEATHER...PERCHA
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1015 AM MST MON SEP 2 2013
.UPDATE...TO AVIATION DISCUSSION...
.SYNOPSIS...
LINGERING MONSOON MOISTURE...ALONG WITH WARMER AFTERNOONS...AND A
FEW HARD TO TIME WEATHER DISTURBANCES WILL RESULT IN A SLIGHT CHANCE
OF AFTERNOON AND EVENING THUNDERSTORMS REGION WIDE THIS WEEK.
&&
.DISCUSSION...
A VORT MAX...CURRENTLY CENTERED NEAR BLYTHE HELPED TRIGGER
CONSIDERABLE STORM ACTIVITY OVER SONORA LAST NIGHT WHICH LEAD TO AN
MCV NEAR THE MEXICO BORDER. THIS FEATURE KEPT CONVECTION GOING AND
MOVED INTO PIMA COUNTY. GUSTY WINDS FROM THOSE STORMS HAVE MADE IT
INTO THE PHOENIX AREA ALREADY. SURPRISINGLY DUSTY GIVEN THE
UNDERWHELMING STRENGTH OF THE WINDS AND LACK OF VIS REDUCTION AT
CGZ. DUST WILL IMPROVE SHORTLY. MADE SOME UPDATES TO THE FORECASTS
EARLIER TO INTRODUCE SLIGHT CHANCE POPS OVER PORTIONS OF
YUMA...SOUTHWEST MARICOPA...AND WESTERN PINAL COUNTIES FOR THIS
MORNING. ALSO NUDGED UP POPS A BIT FOR THIS AFTERNOON...INCLUDING
LOW END SLIGHT CHANCES FOR THE PHOENIX AREA. STORM ACTIVITY THAT HAD
BE CLOSER TO THE CENTER OF THE MCV HAVE WEAKENED QUITE A BIT BUT NEW
STORMS HAVE DEVELOPED ON THE WESTERN PERIPHERY OF IT AS OF THIS
WRITING. HRRR MODEL REFLECTS THIS FEATURE BUT HAS BEEN INDICATING
SOUTHWEST MARICOPA COUNTY GETTING MORE INVOLVED THAN IT HAS. IT GOES
ON TO DEVELOP A GOOD DEAL OF STORMS OVER SOUTHWEST ARIZONA AS WELL
AS STORMS ALONG A THE SPINE OF HIGHEST TERRAIN IN OUR ZONE 24.
NEITHER OF THE 06Z RUNS OF THE NMM6KM NOR OUR LOCAL WRF DEPICTED ANY
OF THE CONVECTION THIS MORNING. 12Z SOUNDINGS INDICATE GOOD MIXED
LAYER CAPE...ESPECIALLY TWC. HOWEVER...THIS VERY FEATURE MAY WIND UP
INHIBITING STORM COVERAGE OVER THE SOUTH-CENTRAL ARIZONA DESERTS
LATER TODAY DUE TO BOUNDARY LAYER STABILIZATION THAT OCCURRED
UPSTREAM FROM THE RAIN COOLED AIR. FOR SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA...THE AFOREMENTIONED DISTURBANCE WHICH
INITIATED THINGS TODAY HAS NOT HAD MUCH IMPACT SO FAR.
HOWEVER...THERE ARE MORE DISTURBANCES TO COME ASSOCIATED WITH THE
REMNANTS OF KIKO WHICH MAY PROVIDE A LITTLE DYNAMICAL NUDGE TO AID
IN STORM ACTIVITY. SO ABOVE NORMAL POPS CONTINUE THERE. WILL
CONTINUE TO EVALUATE. MORE LATER.
&&
.PREVIOUS DISCUSSION...ISSUED AT 300 AM...
TODAY AND TUESDAY...
MOST OF THE CONVECTIVE POTENTIAL MONDAY WILL LIKELY BE FOCUSED OVER
PORTIONS OF SOUTHEAST CA AND THE COLORADO RIVER VALLEY...AS
ACCELERATING UPPER LEVEL SOUTHERLY WINDS FLOW INTO AN INCREASING
JETMAX OVER EASTERN NEVADA. IN OTHER WORDS...ENTRANCE REGION
DYNAMICS IS EXPECTED OVER SOUTHEAST CA. THE HIGHEST PRECIP
PROBABILITIES WILL BE IN THAT REGION. DITTO ON TUESDAY. THE
REMAINDER OF THE FORECAST AREA...SOUTHWEST AND SOUTH CENTRAL AZ WILL
BE DEVOID OF ANY UPPER LEVEL SUPPORT...THEREFORE A SLIGHT CHANCE OF
HEAT OF THE DAY SHOWERS AND THUNDERSTORMS WILL EXIST...WITH SOMEWHAT
HIGHER PROBABILITIES IN THE MOUNTAINS OF SOUTHERN GILA COUNTY.
ALSO ON TUESDAY...AN INVERTED TROF IS FORECAST TO MOVE INTO
SOUTHEAST AZ FROM WEST TEXAS BY EVENING. THEREFORE WE HAVE DECIDED
TO GO WITH A HIGHER PRECIP PROBABILITY OVER PORTIONS OF SOUTH
CENTRAL AZ...INCLUDING THE DESERTS AROUND PHOENIX AND CASA GRANDE.
MODELS FORECAST THE INVERTED TROF MAY ALSO SUPPORT A FEW NOCTURNAL
SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL AZ INTO WEDNESDAY
MORNING.
WEDNESDAY THROUGH SUNDAY...
IN THE AFTER-MATH OF THE ABOVE MENTIONED INVERTED TROF TUESDAY
AFTERNOON AND EVENING...DRIER AIR IS FORECAST TO SPREAD INTO EASTERN
AZ. BUT WITH WARMER AFTERNOONS...INSTABILITY TSTMS ARE STILL
POSSIBLE IN THE MOUNTAINS. A SLIGHT CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE ALSO FORECAST ON THE DESERTS AS MODELS HINT THAT A
FEW WEAK INVERTED TROFS WILL FLOW INTO THE REGION FROM MEXICO UNDER
SOUTHERLY FLOW ALOFT. THESE FEATURES WILL BE HARD TO TIME.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
BLOWING DUST GENERATED BY OUTFLOWS FROM THUNDERSTORMS THAT
DEVELOPED EARLIER THIS MORNING OVER FAR SOUTHERN ARIZONA IS NOW
MOVING THROUGH THE GREATER PHOENIX AREA...REDUCING VISIBILITIES TO
AS LOW AS 1 MILE AT SKY HARBOR. THIS DUST IS EXPECTED TO CONTINUE TO
MOVE NORTHWARD AND AFFECT KSDL OVER THE NEXT 1/2 HOUR OR SO AS WELL.
VISIBILITIES ARE EXPECTED TO BEGIN TO IMPROVE BY 18Z AS THE WINDS
DIMINISH. THERE IS A SLIGHT CHANCE THAT THUNDERSTORMS...OR DUST
STORMS COULD AFFECT THE TERMINALS LATE THIS AFTERNOON OR EVENING AS
WELL...BUT CONFIDENCE IS TOO LOW TO INCLUDE THEM IN THE TAFS...AT
THIS TIME.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY SCT CLOUDS AOA 25KFT WILL LINGER THROUGH THE MORNING WITH
LIGHT WINDS CONTINUING. BY AFTERNOON...STORM DEVELOPMENT OVER THE
HIGHER TERRAIN IS EXPECTED WITH MODERATE CONFIDENCE OF STORMS
DEVELOPING ACROSS OR DOWN INTO THE DESERTS...INCLUDING NEAR KIPL AND
KBLH. INTRODUCED VCSH FOR THE AFTERNOON WITH WEST TO SW WINDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DRIER AIR WILL MOVE INTO THE REGION AS THE WEEK PROGRESSES. WHILE
AFTERNOON SHOWERS AND THUNDERSTORMS WILL REMAIN A POSSIBILITY EACH
AFTERNOON...STORMS SHOULD BECOME INCREASINGLY CONFINED TO THE HIGHER
TERRAIN EAST OF PHOENIX...WITH LITTLE TO NO ACTIVITY ACROSS THE
DESERTS. HUMIDITIES EACH AFTERNOON WILL DROP INTO THE 15 TO 20
PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY ANTICIPATED. WEDNESDAY
AND THURSDAY...INCREASED EAST TO SOUTHEASTERLY FLOW IS ANTICIPATED
ACROSS SOUTHERN AND SOUTH CENTRAL ARIZONA...OTHERWISE WINDS WILL
FAVOR THE TYPICAL UPSLOPE/DOWNVALLEY PATTERNS WITH NO MAJOR WIND
EVENTS ANTICIPATED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...PERCHA/NOLTE
FIRE WEATHER...LEINS/NOLTE
AREA FORECAST DISCUSSION
NWS TUCSON AZ
1000 AM MST MON SEP 2 2013
.SYNOPSIS...SUFFICIENT MOISTURE WILL KEEP ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST ARIZONA THIS WEEK.
AFTERNOON HIGH TEMPERATURES WILL REMAIN SEVERAL DEGREES ABOVE
NORMAL.
&&
.DISCUSSION...KEMX WSR-88D DETECTED SCATTERED TO NUMEROUS 30-50 DBZ
ECHOES ACROSS MUCH OF WRN PIMA COUNTY...THE TOHONO O`ODHAM NATION...
AND SANTA CRUZ COUNTY AT 1655Z. THE REST OF SE AZ WAS VOID OF PRECIP
ECHOES AT THIS TIME. IR/VISIBLE SATELLITE IMAGERY AND RADAR IMAGERY
DEPICTED THE CYCLONIC CIRCULATION CENTER ASSOCIATED WITH THE MCS
MOVING WWD ACROSS SE AZ TO BE JUST SW OF TUCSON.
OTHERWISE...DEWPOINTS VALID 16Z RANGED FROM THE MID 50S NEAR THE NEW
MEXICO BORDER TO THE MID 60S ACROSS WRN PIMA COUNTY. THESE TEMPS
WERE ABOUT 5-10 DEGS F LOWER ACROSS ERN SECTIONS VERSUS 24 HOURS
AGO...AND THESE TEMPS ELSEWHERE WERE NEARLY IDENTICAL TO THIS TIME
SUN. SURFACE TEMPS VALID 16Z WERE ABOUT 5-10 DEGS F COOLER VERSUS 24
HOURS AGO. 02/12Z UPPER AIR PLOTS INDICATED 593 DM HIGH PRESSURE
CENTERED OVER EAST CENTRAL NEW MEXICO...AND A DEEP LOW PRESSURE
SYSTEM CENTERED JUST OFF THE PACIFIC NW COAST. A LIGHT TO MODERATE
GENERALLY SELY FLOW REGIME PREVAILED OVER SE AZ.
ONGOING MCS PRESENTS A FORECAST CHALLENGE FOR THE REST OF TODAY.
02/14Z RUC HRRR WAS TOO FAR SE AT 16Z (9 AM MST) WITH THE MCS...
WITH THE STRONGEST COMP REFL ECHOES CENTERED OVER FAR WRN SANTA CRUZ
COUNTY. MEANWHILE...THE 02/12Z UNIV OF AZ WRF-NAM WAS ALSO TOO FAR
EAST WITH THE ONGOING COMP REFL ECHOES. THE HRRR SUBSEQUENTLY
DEVELOPS ISOLATED TO PERHAPS SCATTERED SHOWERS/TSTMS MAINLY NEAR THE
MOUNTAINS OF COCHISE AND SWRN GRAHAM COUNTIES THIS AFTERNOON
FOLLOWED BY VERY LIMITED COVERAGE OF PRECIP INTO EARLY THIS EVENING.
THE WRF-NAM WAS SIMILAR TO THE RUC HRRR...EXCEPT THAT ANOTHER
CONVECTIVE COMPLEX IS DEPICTED TO OCCUR ESSENTIALLY ACROSS THE SAME
AREA WHERE THE MCS MOVED EARLIER.
AT ANY RATE...WILL LIKELY MODIFY THE GRIDDED DATA POP FIELDS FOR
THIS AFTERNOON AND THIS EVENING TO REFLECT REDUCED RAIN CHANCES FOR
THE VALLEYS. MOUNTAIN POPS OF 30-50 PERCENT SHOULD BE SUFFICIENT.
WILL LIKELY REDUCE HIGH TEMPS THIS AFTERNOON FROM TUCSON WWD AT
LEAST A FEW DEGREES.
PER COORD WITH NCEP SDM...A SPECIAL 18Z KTWC SOUNDING WILL BE
ATTEMPTED.
PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION FOR ADDITIONAL
DETAIL.
&&
.PREV DISCUSSION /647 AM MST MON SEP 2 2013/...TUESDAY CONTINUES TO
LOOK LIKE THE MOST ACTIVE DAY OF THE WEEK WITH HIGHER TERRAIN STORMS
MOVING INTO THE LOWER DESERTS DUE TO 15-20 MPH MID LEVEL STEERING
FLOW. AGAIN HIGHEST PW VALUES WILL BE WEST OF TUCSON.
WEDNESDAY...ISOLATED TO SCATTERED STORMS WITH BEST CHANCES OF STORMS
BEING SOUTH AND WEST OF TUCSON.
LOW GRADE MONSOON FORECAST THURSDAY INTO THE UPCOMING WEEKEND.
ABOVE NORMAL HIGHS WILL CONTINUE THRU MUCH OF THE WEEK.
&&
.AVIATION...SCT TSRA/SHRA WEST AND SOUTH OF KTUS THRU 20Z AS A
CONVECTIVE COMPLEX MOVES WWD ACROSS SE AZ. THEREAFTER...ISOLD-SCT
TSRA/SHRA AREAWIDE INTO THIS EVENING FOLLOWED BY ISOLD -SHRA LATE
TONIGHT INTO EARLY TUESDAY MORNING. THE STRONGER TSRA WILL PRODUCE
MVFR CIGS/VSBYS AND BRIEF WIND GUSTS TO AROUND 45 KTS. SURFACE WIND
WILL GENERALLY BE LESS THAN 10 KTS THRU TUESDAY MORNING OR 03/18Z.
AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A MOIST AIRMASS WILL LEAD TO THE DAILY CYCLE OF
ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS
THIS WEEK. STRONG...GUSTY AND ERRATIC WINDS WILL OCCUR WITH THE
STRONGER THUNDERSTORMS. OTHERWISE...HIGH PRESSURE CENTERED NORTH AND
EAST OF THE AREA WILL PROVIDE A SURFACE WIND FLOW REGIME GENERALLY
FROM THE EAST TO SOUTHEAST DURING MUCH OF THIS WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
BF
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
950 AM MST MON SEP 2 2013
.SYNOPSIS...
LINGERING MONSOON MOISTURE...ALONG WITH WARMER AFTERNOONS...AND A
FEW HARD TO TIME WEATHER DISTURBANCES WILL RESULT IN A SLIGHT CHANCE
OF AFTERNOON AND EVENING THUNDERSTORMS REGION WIDE THIS WEEK.
&&
.DISCUSSION...
A VORT MAX...CURRENTLY CENTERED NEAR BLYTHE HELPED TRIGGER
CONSIDERABLE STORM ACTIVITY OVER SONORA LAST NIGHT WHICH LEAD TO AN
MCV NEAR THE MEXICO BORDER. THIS FEATURE KEPT CONVECTION GOING AND
MOVED INTO PIMA COUNTY. GUSTY WINDS FROM THOSE STORMS HAVE MADE IT
INTO THE PHOENIX AREA ALREADY. SURPRISINGLY DUSTY GIVEN THE
UNDERWHELMING STRENGTH OF THE WINDS AND LACK OF VIS REDUCTION AT
CGZ. DUST WILL IMPROVE SHORTLY. MADE SOME UPDATES TO THE FORECASTS
EARLIER TO INTRODUCE SLIGHT CHANCE POPS OVER PORTIONS OF
YUMA...SOUTHWEST MARICOPA...AND WESTERN PINAL COUNTIES FOR THIS
MORNING. ALSO NUDGED UP POPS A BIT FOR THIS AFTERNOON...INCLUDING
LOW END SLIGHT CHANCES FOR THE PHOENIX AREA. STORM ACTIVITY THAT HAD
BE CLOSER TO THE CENTER OF THE MCV HAVE WEAKENED QUITE A BIT BUT NEW
STORMS HAVE DEVELOPED ON THE WESTERN PERIPHERY OF IT AS OF THIS
WRITING. HRRR MODEL REFLECTS THIS FEATURE BUT HAS BEEN INDICATING
SOUTHWEST MARICOPA COUNTY GETTING MORE INVOLVED THAN IT HAS. IT GOES
ON TO DEVELOP A GOOD DEAL OF STORMS OVER SOUTHWEST ARIZONA AS WELL
AS STORMS ALONG A THE SPINE OF HIGHEST TERRAIN IN OUR ZONE 24.
NEITHER OF THE 06Z RUNS OF THE NMM6KM NOR OUR LOCAL WRF DEPICTED ANY
OF THE CONVECTION THIS MORNING. 12Z SOUNDINGS INDICATE GOOD MIXED
LAYER CAPE...ESPECIALLY TWC. HOWEVER...THIS VERY FEATURE MAY WIND UP
INHIBITING STORM COVERAGE OVER THE SOUTH-CENTRAL ARIZONA DESERTS
LATER TODAY DUE TO BOUNDARY LAYER STABILIZATION THAT OCCURRED
UPSTREAM FROM THE RAIN COOLED AIR. FOR SOUTHWEST ARIZONA AND
SOUTHEAST CALIFORNIA...THE AFOREMENTIONED DISTURBANCE WHICH
INITIATED THINGS TODAY HAS NOT HAD MUCH IMPACT SO FAR.
HOWEVER...THERE ARE MORE DISTURBANCES TO COME ASSOCIATED WITH THE
REMNANTS OF KIKO WHICH MAY PROVIDE A LITTLE DYNAMICAL NUDGE TO AID
IN STORM ACTIVITY. SO ABOVE NORMAL POPS CONTINUE THERE. WILL
CONTINUE TO EVALUATE. MORE LATER.
&&
.PREVIOUS DISCUSSION...ISSUED AT 300 AM...
TODAY AND TUESDAY...
MOST OF THE CONVECTIVE POTENTIAL MONDAY WILL LIKELY BE FOCUSED OVER
PORTIONS OF SOUTHEAST CA AND THE COLORADO RIVER VALLEY...AS
ACCELERATING UPPER LEVEL SOUTHERLY WINDS FLOW INTO AN INCREASING
JETMAX OVER EASTERN NEVADA. IN OTHER WORDS...ENTRANCE REGION
DYNAMICS IS EXPECTED OVER SOUTHEAST CA. THE HIGHEST PRECIP
PROBABILITIES WILL BE IN THAT REGION. DITTO ON TUESDAY. THE
REMAINDER OF THE FORECAST AREA...SOUTHWEST AND SOUTH CENTRAL AZ WILL
BE DEVOID OF ANY UPPER LEVEL SUPPORT...THEREFORE A SLIGHT CHANCE OF
HEAT OF THE DAY SHOWERS AND THUNDERSTORMS WILL EXIST...WITH SOMEWHAT
HIGHER PROBABILITIES IN THE MOUNTAINS OF SOUTHERN GILA COUNTY.
ALSO ON TUESDAY...AN INVERTED TROF IS FORECAST TO MOVE INTO
SOUTHEAST AZ FROM WEST TEXAS BY EVENING. THEREFORE WE HAVE DECIDED
TO GO WITH A HIGHER PRECIP PROBABILITY OVER PORTIONS OF SOUTH
CENTRAL AZ...INCLUDING THE DESERTS AROUND PHOENIX AND CASA GRANDE.
MODELS FORECAST THE INVERTED TROF MAY ALSO SUPPORT A FEW NOCTURNAL
SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL AZ INTO WEDNESDAY
MORNING.
WEDNESDAY THROUGH SUNDAY...
IN THE AFTER-MATH OF THE ABOVE MENTIONED INVERTED TROF TUESDAY
AFTERNOON AND EVENING...DRIER AIR IS FORECAST TO SPREAD INTO EASTERN
AZ. BUT WITH WARMER AFTERNOONS...INSTABILITY TSTMS ARE STILL
POSSIBLE IN THE MOUNTAINS. A SLIGHT CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE ALSO FORECAST ON THE DESERTS AS MODELS HINT THAT A
FEW WEAK INVERTED TROFS WILL FLOW INTO THE REGION FROM MEXICO UNDER
SOUTHERLY FLOW ALOFT. THESE FEATURES WILL BE HARD TO TIME.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
EXPECT SCT TO BKN DEBRIS CLOUDS FROM NOCTURNAL CONVECTION ALONG THE
INTL BORDER TO DRIFT NORTHWARD THROUGH THE MORNING REMAINING AOA
20KFT. EASTERLY MORNING WINDS WILL TURN WEST THROUGH THE AFTERNOON.
AFTERNOON AND EVENING MOUNTAIN STORMS TO THE NORTH AND EAST OF
PHOENIX ARE POSSIBLE...WITH LIMITED CHANCES OF STORMS SURVIVING NEAR
THE PHOENIX AREA TERMINALS. CONFIDENCE REMAINS MOSTLY LOW FOR STORMS
AND STORM OUTFLOWS IMPACTING THE TERMINALS TONIGHT.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
MOSTLY SCT CLOUDS AOA 25KFT WILL LINGER THROUGH THE MORNING WITH
LIGHT WINDS CONTINUING. BY AFTERNOON...STORM DEVELOPMENT OVER THE
HIGHER TERRAIN IS EXPECTED WITH MODERATE CONFIDENCE OF STORMS
DEVELOPING ACROSS OR DOWN INTO THE DESERTS...INCLUDING NEAR KIPL AND
KBLH. INTRODUCED VCSH FOR THE AFTERNOON WITH WEST TO SW WINDS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DRIER AIR WILL MOVE INTO THE REGION AS THE WEEK PROGRESSES. WHILE
AFTERNOON SHOWERS AND THUNDERSTORMS WILL REMAIN A POSSIBILITY EACH
AFTERNOON...STORMS SHOULD BECOME INCREASINGLY CONFINED TO THE HIGHER
TERRAIN EAST OF PHOENIX...WITH LITTLE TO NO ACTIVITY ACROSS THE
DESERTS. HUMIDITIES EACH AFTERNOON WILL DROP INTO THE 15 TO 20
PERCENT RANGE WITH GOOD OVERNIGHT RECOVERY ANTICIPATED. WEDNESDAY
AND THURSDAY...INCREASED EAST TO SOUTHEASTERLY FLOW IS ANTICIPATED
ACROSS SOUTHERN AND SOUTH CENTRAL ARIZONA...OTHERWISE WINDS WILL
FAVOR THE TYPICAL UPSLOPE/DOWNVALLEY PATTERNS WITH NO MAJOR WIND
EVENTS ANTICIPATED.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...NOLTE
FIRE WEATHER...LEINS/NOLTE
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
200 PM PDT MON SEP 2 2013
.SYNOPSIS...
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
CONTINUE THROUGH TUESDAY...FAVORING THE MOUNTAINS OF LOS ANGELES AND
VENTURA COUNTIES AS WELL AS THE ANTELOPE VALLEY. OVERNIGHT LOWS AND
DAYTIME HIGHS WILL REMAIN ABOVE NORMAL THROUGH THE WEEK...WITH
ADDITIONAL WARMING THROUGH THE END OF THE WEEK...AND POSSIBLY A FEW
DEGREES OF COOLING ON THE WEEKEND.
&&
.SHORT TERM (TODAY-THU)...ANOTHER SLOW START TO AFTERNOON CONVECTION
IN THE MTNS TODAY BUT ENOUGH INSTABILITY AND MOISTURE TO KEEP SLIGHT
CHANCES GOING. SOUTHERLY FLOW IS STRONG ENOUGH TO LIMIT THE
POTENTIAL FOR FLASH FLOODING BUT STILL SOME CONCERNS THERE,
ESPECIALLY OUT IN THE ANTELOPE VALLEY WHERE IT DOESN`T TAKE MUCH TO
CAUSE PROBLEMS.
BIGGEST ADJUSTMENT TO THE FORECAST TODAY WAS TO ADD IN SMALL
SHOWER/TSTORM CHANCES TO ALL AREAS TONIGHT WITH A WAVE MOVING UP
FROM THE SOUTH, ORIGINATING FROM OLD TROPICAL STORM KIKO. WATER
VAPOR SHOWS WHAT APPEARS TO BE A LITLE UPPER LEVEL CIRCULATION NEAR
30N/120W MOVING SLOWLY NORTH WITH A FAIRLY LARGE BATCH OF MOISTURE
OUT AHEAD OF IT. THE GFS SEEMS TO HAVE THE BEST HANDLE ON IT, WITH
THE VORT AT 18Z ALMOST DEAD ON. THEN MOVING IT TO NEAR SAN NICOLAS
ISLAND AROUND 06Z AND INTO SRN SBA COUNTY AROUND 12Z. THE
MOISTURE THOUGH IS WELL AHEAD OF IT AND MODELS SHOW DECENT
INSTABILITY TONIGHT OVER THE ENTIRE AREA FROM SBA COUNTY SOUTH.
PWATS EXPECTED TO INCREASE AGAIN BACK UP TO CLOSE TO 2" BY TUESDAY
MORNING. AND THE HRRR MODEL ACTUALLY SHOWS SOME PRECIP DEVELOPING
LATER IN THE EVENING ACROSS VENTURA AND LA COUNTIES. SO GIVEN ALL
THIS IT SEEMS PRUDENT TO GO WITH SOME SLIGHT CHANCES FOR SHOWERS AND
TSTORMS ACROSS THE ENTIRE AREA FROM SBA COUNTY SOUTH TONIGHT, THEN
SPREADING UP INTO SLO COUNTY LATER TONIGHT AND TUESDAY MORNING AS
THAT VORT MOVES NORTH. NKX RADAR PICKING UP ON SOME RETURNS BUT THEY
ARE OVER 100 NM OFFSHORE SO IT`S HARD TO SAY IF ANYTHING IS REACHING
THE SURFACE.
ONCE THAT WAVE MOVES THROUGH WE SHOULD TRANSITION TO MORE A TYPICAL
MTN/DESERT THUNDERSTORM PATTERN IN THE AFTERNOON. WITH THE HIGHER
PWATS AND 850 DEWPOINTS WE WILL HAVE TO AGAIN CONSIDER FLASH FLOOD
WATCHES FOR THE INTERIOR, THOUGH STEERING WINDS ARE STILL IN THE
15-20 KT RANGE SO THAT WILL HELP KEEP STORMS MOVING A BIT. THE OTHER
FACTOR TO CONSIDER FOR TOMORROW IS THE AMOUNT OF MID LEVEL CLOUD
COVER LEFT OVER FROM TONIGHT THAT MAY DELAY THE HEATING.
HIGHS EXPECTED TO WARM A COUPLE DEGREES MOST AREAS TUESDAY WITH
SLIGHTLY HIGHER HUMIDITIES AS WELL. CLOUDS WILL PLAY A ROLE HERE TOO
SO IF CLEARING IS DELAYED THEN TEMPS MAY NOT WARM UP AS MUCH AS
EXPECTED.
HIGH PRESSURE EXPECTED TO EXPAND WESTWARD FOR THE MIDDLE AND END OF
THE WEEK AND WILL CONTINUE THE WARMING TREND. TEMPS EXPECTED TO PEAK
THU/FRI WITH WARMER VALLEY HIGHS 100-105 AND COASTAL AREAS AWAY FROM
THE IMMEDIATE COAST IN THE 80S TO LOWER 90S. STILL ENOUGH MOISTURE
AND INSTABILITY TO KEEP SOME SMALL TSTORM CHANCES DURING THE
AFTERNOON, MAINLY EASTERN LA COUNTY.
.LONG TERM (FRI-MON)...AFTER ANOTHER HOT DAY FRIDAY TEMPS EXPECTED
TO TREND COOLER THROUGH THE WEEKEND, THOUGH NOT DRAMATICALLY. STILL
SHOULD BE AT LEAST A FEW DEGREES ABOVE NORMAL EVEN BY MONDAY. TSTORM
CHANCES SEEM VERY LOW AT THIS TIME WITH MONSON MOISTURE PUSHED EAST
OF THE AREA, THOUGH THAT COULD EASILY CHANGE.
&&
.AVIATION...02/1800Z.
POOR TO MODERATE CONFIDENCE IN THE 18Z TAFS. AN AREA OF SUBTROPICAL
MOISTURE IS MOVING TOWARD THE FORECAST AREA AND WILL ARRIVE TONIGHT.
THE EXTENSIVE MID LEVEL CLOUDINESS IS EXPECTED TO DISRUPT MARINE
CLOUD FORMATION AND LOW CLOUD DEVELOPMENT HAS BEEN SCALED BACK AT
THE COASTAL SITES FOR TONIGHT. THERE IS POOR CONFIDENCE IN THE TAFS
FOR COASTAL LA COUNTY AND MODERATE CONFIDENCE ELSEWHERE.
KLAX...POOR CONFIDENCE IN THE DEVELOPMENT OF MARINE CLOUDS TONIGHT.
DECIDED TO SCALE BACK LOW CLOUD COVERAGE TO SCT DUE TO EXTENSIVE MID
LEVEL CLOUD COVERAGE. THERE IS A 40 PERCENT CHANCE OF IFR CEILINGS
CAUSED BY MARINE CLOUDS.
KBUR...MODERATE CONFIDENCE IN VFR CONDITIONS THROUGH TUESDAY.
&&
.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).
&&
$$
PUBLIC...MW
AVIATION...SWEET
SYNOPSIS...BARTLING
WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS PUEBLO CO
149 AM MDT MON SEP 2 2013
.UPDATE...
ISSUED AT 145 AM MDT MON SEP 2 2013
BROUGHT FRONT END GRIDS INTO ALIGNMENT WITH CURRENT OBSERVATIONS
AND TRENDS. NO MAJOR UPDATES TO OVERALL FORECAST AT THIS TIME. LW
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 226 PM MDT SUN SEP 1 2013
ABUNDANT MOISTURE IS OVER THE AREA TODAY. THE MONSOON PLUME LIES
OVERHEAD AND SFC DEW POINTS RANGE FROM THE UPR 40S TO LOWER 60S ACRS
MOST OF THE AREA...AND LCL/S ARE LOWER TODAY...ALL LEADING TO A
BETTER POTENTIAL FOR HEAVY RAINFALL TODAY. LOW LEVEL UPSLOPE FLOW
COULD HELP ENHANCE CONVECTION ALONG AND NR THE MTS AND COULD LEAD TO
A TRAINING EFFECT. THE UPR LEVEL FLOW IS NORTHWESTERLY AROUND 15
KTS SO IN GENERAL THE STORMS SHOULD MOVE TOWARD THE SOUTHEAST THIS
EVENING. SHOWERS AND TSTMS OVER THE MOUNTAINS EARLY THIS AFTERNOON
SHOULD INCREASE IN COVERAGE AND SPREAD TO THE LOWER ELEVATIONS.
HOWEVER THE NAM12 AND RAP13 SHOW LITTLE CONVECTION OUT OVR THE SERN PLAINS
THIS EVENING AND QUICKLY END PCPN BY MIDNIGHT OVR ALL AREAS EXCEPT
ALONG THE CONTDVD. THE HRRR SHOWS A LINE OF CONVECTION MOVING OUT
OVR THE SERN PLAINS EARLY IN THE EVENING BUT DOESN/T REALLY MOVE IT
PAST LA JUNTA.
OVERNIGHT THE MODELS SHOW THE MONSOON MSTR PLUME SHIFTING SOUTH OF
THE AREA...AND THEN ON MON THAT PLUME IS EXPECTED TO BE OVR THE
MOUNTAIN AREAS...WITH DRIER UPR LEVELS FROM THE I-25 CORRIDOR AND
WESTWARD. AT THE LOWER LEVELS DEW POINTS ARE STILL EXPECTED TO
REMAIN FAIRLY HIGH...IN THE UPPER 40S AND 50S. LCL/S ARE EXPECTED
TO BE A LITTLE HIGHER ON MON. BEST CHANCES FOR PCPN ON MON WL BE
OVR THE NR THE MTS...WITH SOME STORMS LIKELY MOVING OUT OVR THE I-25
CORRIDOR...BUT MUCH OF THE REST OF THE PLAINS COULD BE DRY. WE COULD
AGAIN SEE SOME LOCALLY HEAVY RAIN ON MON AND IF ANY OF THESE
STRONGER STORMS MOVE OVER THE BURN SCARS...THERE WL AGAIN BE THE
THREAT OF FLASH FLOODING.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 226 PM MDT SUN SEP 1 2013
UPPER LEVEL HIGH PRESSURE WILL REMAIN CENTERED OVER COLORADO THROUGH
AT LEAST FRIDAY. UPPER LOW SLOWLY MOVES ONSHORE IN THE PACIFIC
NORTHWEST FRIDAY/SATURDAY TIMEFRAME. MODELS A BIT SLOWER WITH THIS
FEATURE THAN RUNS FROM 24 HOURS AGO...LIKELY DUE TO THE BLOCKINESS
OF THE PATTERN.
THIS DOMINANT RIDGE MEANS A RETURN TO UNSEASONABLY WARM CONDITIONS.
THUNDERSTORM CHANCES THROUGH THE WORK WEEK WILL BE PRIMARILY
CONFINED TO THE MOUNTAINS AND WEST...ALTHOUGH MODELS HINT AT A SUBTLE
UPPER DISTURBANCE MOVING THROUGH THE HIGH PLAINS AND SENDING A WEAK
FRONTAL BOUNDARY THROUGH THE EAST CENTRAL PLAINS WEDNESDAY AFTERNOON
WHICH COULD TRIGGER SOME CONVECTION ON THE PALMER DIVIDE. LITTLE IN
THE WAY OF MID AND UPPER LEVEL MOISTURE THOUGH...SO FLASH FLOOD
THREAT WILL BE LOWER.
RIDGE GETS FLATTENED AND AXIS SHUNTED OFF TO THE EAST SATURDAY NIGHT
AND SUNDAY AS LOW PRESSURE MOVES EAST ALONG THE US/CANADIAN BORDER.
COULD SEE A DECENT COLD FRONT MOVE THROUGH THE PLAINS NEXT WEEKEND
IF THE MODELS REMAIN CONSISTENT WITH THE TIMING OF THIS SYSTEM. IF
SO, COOLER TEMPERATURES AND A BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS ARE POSSIBLE SOMETIME NEXT WEEKEND.
IN THE MEANTIME, DESPITE TEMPERATURES WARMING TO ABOVE NORMAL LEVELS
THIS WEEK...GUIDANCE NUMBERS REMAIN TOO WARM. WILL CONTINUE TREND OF
SHAVING A FEW DEGREES OFF GUIDANCE HIGHS. STARK
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN SEP 1 2013
WEAK SOUTHEAST SURFACE WINDS HAVE HELPED STRATUS DEVELOP AT KCOS
AND KFLY AS OF 05Z...AND EXPECT MVFR STRATUS TO PERSIST ALONG AND
SOUTH OF THE PALMER DIVIDE...INCLUDING KCOS...UNTIL AROUND 15Z.
SUSPECT LOWER CLOUDS WILL STAY NORTH OF KPUB...SO WILL CONTINUE
WITH VFR CONDITIONS HERE THROUGH SUNRISE. OVER THE
MOUNTAINS...PATCHY MVFR CIGS/VIS WITH WEAKENING -SHRA WILL PERSIST
THROUGH 07-09Z...WITH MOST MOUNTAINS CLEARING BY 12Z. ON
MON...TSRA WILL AGAIN DEVELOP OVER THE MOUNTAINS AFTER 18Z...BEST
CHANCES WILL BE SOUTHERN SANGRES...SAN JUANS AND AREAS NEAR THE NM
BORDER. TAF SITES WILL STAY VFR THROUGH THE DAY...THOUGH THERE IS
A HIGH ENOUGH CHANCE OF A TSRA AT KALS TO INCLUDE A VCTS AFTER
20Z. TSRA CHANCES AT KPUB AND KCOS ARE NON-ZERO...BUT LOOK TOO LOW
TO INCLUDE IN THE TAF AT THIS POINT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...LW
SHORT TERM...28
LONG TERM...STARK
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1126 PM MDT SUN SEP 1 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 226 PM MDT SUN SEP 1 2013
ABUNDANT MOISTURE IS OVER THE AREA TODAY. THE MONSOON PLUME LIES
OVERHEAD AND SFC DEW POINTS RANGE FROM THE UPR 40S TO LOWER 60S ACRS
MOST OF THE AREA...AND LCL/S ARE LOWER TODAY...ALL LEADING TO A
BETTER POTENTIAL FOR HEAVY RAINFALL TODAY. LOW LEVEL UPSLOPE FLOW
COULD HELP ENHANCE CONVECTION ALONG AND NR THE MTS AND COULD LEAD TO
A TRAINING EFFECT. THE UPR LEVEL FLOW IS NORTHWESTERLY AROUND 15
KTS SO IN GENERAL THE STORMS SHOULD MOVE TOWARD THE SOUTHEAST THIS
EVENING. SHOWERS AND TSTMS OVER THE MOUNTAINS EARLY THIS AFTERNOON
SHOULD INCREASE IN COVERAGE AND SPREAD TO THE LOWER ELEVATIONS.
HOWEVER THE NAM12 AND RAP13 SHOW LITTLE CONVECTION OUT OVR THE SERN PLAINS
THIS EVENING AND QUICKLY END PCPN BY MIDNIGHT OVR ALL AREAS EXCEPT
ALONG THE CONTDVD. THE HRRR SHOWS A LINE OF CONVECTION MOVING OUT
OVR THE SERN PLAINS EARLY IN THE EVENING BUT DOESN/T REALLY MOVE IT
PAST LA JUNTA.
OVERNIGHT THE MODELS SHOW THE MONSOON MSTR PLUME SHIFTING SOUTH OF
THE AREA...AND THEN ON MON THAT PLUME IS EXPECTED TO BE OVR THE
MOUNTAIN AREAS...WITH DRIER UPR LEVELS FROM THE I-25 CORRIDOR AND
WESTWARD. AT THE LOWER LEVELS DEW POINTS ARE STILL EXPECTED TO
REMAIN FAIRLY HIGH...IN THE UPPER 40S AND 50S. LCL/S ARE EXPECTED
TO BE A LITTLE HIGHER ON MON. BEST CHANCES FOR PCPN ON MON WL BE
OVR THE NR THE MTS...WITH SOME STORMS LIKELY MOVING OUT OVR THE I-25
CORRIDOR...BUT MUCH OF THE REST OF THE PLAINS COULD BE DRY. WE COULD
AGAIN SEE SOME LOCALLY HEAVY RAIN ON MON AND IF ANY OF THESE
STRONGER STORMS MOVE OVER THE BURN SCARS...THERE WL AGAIN BE THE
THREAT OF FLASH FLOODING.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 226 PM MDT SUN SEP 1 2013
UPPER LEVEL HIGH PRESSURE WILL REMAIN CENTERED OVER COLORADO THROUGH
AT LEAST FRIDAY. UPPER LOW SLOWLY MOVES ONSHORE IN THE PACIFIC
NORTHWEST FRIDAY/SATURDAY TIMEFRAME. MODELS A BIT SLOWER WITH THIS
FEATURE THAN RUNS FROM 24 HOURS AGO...LIKELY DUE TO THE BLOCKINESS
OF THE PATTERN.
THIS DOMINANT RIDGE MEANS A RETURN TO UNSEASONABLY WARM CONDITIONS.
THUNDERSTORM CHANCES THROUGH THE WORK WEEK WILL BE PRIMARILY
CONFINED TO THE MOUNTAINS AND WEST...ALTHOUGH MODELS HINT AT A SUBTLE
UPPER DISTURBANCE MOVING THROUGH THE HIGH PLAINS AND SENDING A WEAK
FRONTAL BOUNDARY THROUGH THE EAST CENTRAL PLAINS WEDNESDAY AFTERNOON
WHICH COULD TRIGGER SOME CONVECTION ON THE PALMER DIVIDE. LITTLE IN
THE WAY OF MID AND UPPER LEVEL MOISTURE THOUGH...SO FLASH FLOOD
THREAT WILL BE LOWER.
RIDGE GETS FLATTENED AND AXIS SHUNTED OFF TO THE EAST SATURDAY NIGHT
AND SUNDAY AS LOW PRESSURE MOVES EAST ALONG THE US/CANADIAN BORDER.
COULD SEE A DECENT COLD FRONT MOVE THROUGH THE PLAINS NEXT WEEKEND
IF THE MODELS REMAIN CONSISTENT WITH THE TIMING OF THIS SYSTEM. IF
SO, COOLER TEMPERATURES AND A BETTER CHANCE FOR SHOWERS AND
THUNDERSTORMS ARE POSSIBLE SOMETIME NEXT WEEKEND.
IN THE MEANTIME, DESPITE TEMPERATURES WARMING TO ABOVE NORMAL LEVELS
THIS WEEK...GUIDANCE NUMBERS REMAIN TOO WARM. WILL CONTINUE TREND OF
SHAVING A FEW DEGREES OFF GUIDANCE HIGHS. STARK
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1119 PM MDT SUN SEP 1 2013
WEAK SOUTHEAST SURFACE WINDS HAVE HELPED STRATUS DEVELOP AT KCOS
AND KFLY AS OF 05Z...AND EXPECT MVFR STRATUS TO PERSIST ALONG AND
SOUTH OF THE PALMER DIVIDE...INCLUDING KCOS...UNTIL AROUND 15Z.
SUSPECT LOWER CLOUDS WILL STAY NORTH OF KPUB...SO WILL CONTINUE
WITH VFR CONDITIONS HERE THROUGH SUNRISE. OVER THE
MOUNTAINS...PATCHY MVFR CIGS/VIS WITH WEAKENING -SHRA WILL PERSIST
THROUGH 07-09Z...WITH MOST MOUNTAINS CLEARING BY 12Z. ON
MON...TSRA WILL AGAIN DEVELOP OVER THE MOUNTAINS AFTER 18Z...BEST
CHANCES WILL BE SOUTHERN SANGRES...SAN JUANS AND AREAS NEAR THE NM
BORDER. TAF SITES WILL STAY VFR THROUGH THE DAY...THOUGH THERE IS
A HIGH ENOUGH CHANCE OF A TSRA AT KALS TO INCLUDE A VCTS AFTER
20Z. TSRA CHANCES AT KPUB AND KCOS ARE NON-ZERO...BUT LOOK TOO LOW
TO INCLUDE IN THE TAF AT THIS POINT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...STARK
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
402 PM EDT MON SEP 2 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL DIMINISH OVERNIGHT AS DRIER AIR
WORKS INTO THE REGION. BUT ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS IS ANTICIPATED TUESDAY...A FEW OF WHICH MAY BE
STRONG TO SEVERE WITH GUSTY WINDS AND HEAVY RAIN. COOLER AND
DRIER WEATHER IS ANTICIPATED INTO MIDWEEK WITH ANOTHER CHANCE OF
STORMS POSSIBLY BY LATE WEEK...AND ANOTHER CHANCE SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
**FLASH FLOOD WATCH REMAINS IS IN EFFECT TILL 11 PM**
**TURN AROUND...DONT DROWN...
**PLEASE TO NOT DRIVE INTO FLOODED ROADWAYS**
4 PM UPDATE...
UTILIZING THE HRRR AND WRF-ARW TO MAKE DETERMINATIONS ON SHOWER
AND THUNDERSTORM OUTCOMES INTO THE EVENING HOURS. AS MENTIONED IN
EARLIER DISCUSSIONS...LOW-LEVEL FORCING IS APPARENT WHERE THE
BOUNDARY LAYER DESTABILIZES RESULTING IN A LOCALIZATION OF THETAE
LOW-LEVEL CONVERGENCE UNDERNEATH BROAD-SCALE LIFTING OF CYCLONIC
FLOW. A JUICY TROPICAL AIRMASS IN PLACE WITH PWATS AROUND 2+
INCHES...WITH SATURATED SOILS FROM RAINS THE PAST 24 HOURS...AND
THE THREAT OF FLASH FLOODING CONTINUES.
WILL SEE ACTIVITY CONTINUE FOR THE NEXT FEW HOURS...BUT NOTING WATER
VAPOR SATELLITE...DRIER AIR IS WORKING ITS WAY AROUND THE BROADER
LOW PRESSURE CENTER OVER THE NORTHERN GREAT LAKES. TOWARDS EVENING
THIS DRIER AIR SHOULD DISSIPATE ACTIVITY AS SEEN CONSISTENTLY IN
ALL FORECAST GUIDANCE. WILL ALLOW THE FLASH FLOOD WATCH DROP
ACCORDINGLY INTO THE EARLY EVENING HOURS.
TONIGHT...
WHILE THE MID- TO UPPER-LEVEL TROUGH AMPLIFIES...DRIER AIR WORKS
ITS WAY IN. THE BETTER THETAE AXIS OF MOISTURE SHIFTS OFFSHORE AND
OUT TO SEA. ACTIVITY WILL LINGER EASTWARD TOWARDS MIDNIGHT
COLLOCATED WITH THE LOW-LEVEL THETAE CONVERGENCE. THEREAFTER A
LULL IN ACTIVITY IS ANTICIPATED AS THE COLD FRONT PUSHES SOUTH AND
EAST OUT OF THE GREAT LAKES REGION TOWARDS SOUTHERN NEW ENGLAND.
WILL BRING POPS ON A DOWNWARD TREND FROM CHANCE TO SLIGHT CHANCE
WEST TO EAST.
FOG WILL BE AN ISSUE FOR THE SOUTH-SOUTHEAST COAST...AS WELL AS
INTERIOR COASTAL PLAIN. DEWPOINTS IN THE LOW 70S AND RECENT RAINS
WILL MAKE FOR A SOUPY BOUNDARY LAYER PROFILE OVERNIGHT. VISIBILITIES
DOWN TO A QUARTER MILE OR LESS IN PARTS WILL BE POSSIBLE AS WINDS
WEAKEN.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
TUESDAY...
THUNDERSTORMS WILL BE POSSIBLE AHEAD OF A SURFACE COLD FRONT
PUSHING ACROSS SOUTHERN NEW ENGLAND DURING THE MORNING INTO
AFTERNOON HOURS. A FEW OF THESE STORMS MAY BE STRONG TO SEVERE BUT
THERE REMAINS A FAIR AMOUNT OF UNCERTAINTY.
WHAT IS SEEMINGLY CLEAR...IS THAT DEEP LAYER ASCENT IS ENTIRELY
PLAUSIBLE. THE MAIN MID-LEVEL IMPULSE COUPLED WITH THE RIGHT-REAR
QUADRANT OF AN ENHANCING UPPER LEVEL JET SHOULD PROVIDE ENHANCED
ASCENT THROUGH A LAYER OF DECENT MID-LEVEL LAPSE RATES...6 C/KM.
THIS LIFT APPEARS TO BE COLLOCATED ALONG THE SURFACE COLD FRONT
AND ATTENDANT FRONTOGENESIS...ALONG AND AHEAD OF WHICH WILL BE A
SECONDARY TONGUE OF DECENT THEATE AIR.
BUT THE KEY IS TIMING AND INITIAL CONDITIONS. THERE IS SOME
UNCERTAINTY AS TO THE CLEARING PROFILE AHEAD OF THE COLD FRONT
ALLOWING BOUNDARY LAYER DESTABILIZATION. THE FRONT ITSELF MAY
ENCROACH WELL EAST INTO THE FORECAST AREA BY MIDDAY BEFORE ANY
THUNDERSTORM ACTIVITY GETS UNDERWAY. IN ADDITION...THE PREVIOUS
EVENINGS DRY SLOT MAY CLEAR OUT MID- TO UPPER- LEVEL CLOUDS...BUT
BOUNDARY LAYER MOISTURE LIKELY AS LOW CLOUDS AND FOG BY MORNING
MAY LINGER AND LIMIT INSTABILITY. ON A FINAL NOTE...THERE ARE
SUBTLE FORECAST SOUNDING INDICATIONS OF THIN CAPE PROFILES AND
PERHAPS A DRY AIR SUBSIDENCE INVERSION AROUND H7.
CONSIDERING ALL FACTORS...THERE IS SOME POSSIBILITY OF THE
BOUNDARY LAYER DESTABILIZING EAST OF THE CONNECTICUT RIVER VALLEY.
AND COLLOCATING WITH DEEP-LAYER ASCENT. THE WRF-ARW HAS BEEN DOING
WELL THE PAST FEW DAYS WITH THUNDERSTORM OUTCOMES AND EXHIBITS
SOME DEVELOPMENT WITH THE 02.12Z RUN. HAVE HINTED LIKELY POPS
WHERE GREATEST CONFIDENCE LIES...ELSEWHERE CHANCE POPS.
WITH UNIDIRECTIONAL 0-6 KM BULK SHEAR UP TO AROUND 35 KNOTS AND
THE POSSIBILITY OF INSTABILITY AROUND 1000 J/KG...CAN NOT RULE OUT
THE POTENTIAL FOR STRONG TO SEVERE STORMS OVER SOUTHERN AND
SOUTHEAST NEW ENGLAND. MAIN THREATS WILL BE HEAVY RAIN AND GUSTY
WINDS. WILL NOT RULE OUT THE POSSIBILITY OF HAIL. COULD SEE A GOOD
TURNING PROFILE WITHIN THE LOW-LEVELS IF WINDS ARE ABLE TO BACK
AHEAD OF THE COLD FRONT.
THE SURFACE COLD FRONT IS PROGGED TO BE ALONG THE I-95 BOSTON-
PROVIDENCE CORRIDOR BY EVENING.
TUESDAY NIGHT...
SHOWER AND THUNDERSTORM ACTIVITY DIMINISHES TOWARDS MIDNIGHT AS
THE SURFACE COLD FRONT SWEEPS OFFSHORE. WET WEATHER WILL LINGER
FOR THE FAR EAST AND SOUTHEAST. THEREAFTER...WILL SEE WESTERLY
FLOW TO THE REAR OF THE FRONT USHER COOLER AND DRIER AIR. GRADUAL
CLEARING TOWARDS MORNING.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGHLIGHTS...
* ANOTHER ROUND OF SHOWERS POSSIBLE WITH BACK DOOR FRONT THU
* MUCH COOLER/DRIER WEATHER LATE WEEK
* MORE STORMS POSSIBLE OVER THE WEEKEND WITH A COLD FRONT
MODELS ARE IN GOOD AGREEMENT THROUGH MUCH OF THE LONG TERM. THE
MODELS HAVE BEEN FAIRLY CONSISTENT OVER THE LAST FEW DAYS WITH THE
GENERAL SYNOPTIC PATTERN SO CONFIDENCE IN THE BROAD SCALE IS FAIRLY
HIGH. THERE ARE SOME DETAILS AND IN SOME CASES TIMING THAT STILL
NEED TO BE IRONED OUT...PARTICULARLY LATE IN THE WEEKEND INTO EARLY
NEXT WEEK. LOW PRESSURE MOVING OUT OF QUEBEC AND INTO THE MARITIMES
BRINGS A BACK DOOR COLD FRONT THROUGH SOUTHERN NEW ENGLAND THURSDAY.
WITH IT MAY COME A FEW SHOWERS AND THUNDERSTORMS. HIGH PRESSURE
BUILDS IN FOR FRIDAY AND AT LEAST A PART OF SATURDAY AND THEN
ANOTHER COLD FRONT MOVES THROUGH THE AREA NEXT WEEKEND. WILL USE A
BLEND OF THE PREVIOUS FORECAST AND THE WPC GRIDS THAT INCORPORATE
SOME OF THE ENSEMBLE DATA.
WEDNESDAY AND THURSDAY...WHILE THE SHORTWAVE TROUGH MOVES
OFFSHORE...THE BROADER UPPER TROUGH MOVES OVER SOUTHERN NEW ENGLAND
WEDNESDAY. LOW PRESSURE MOVING INTO THE MARITIMES WEDNESDAY WILL
BRING A BACK DOOR COLD FRONT SOUTH THROUGH NORTHERN NEW ENGLAND BY
EARLY THURSDAY MORNING AND THROUGH SOUTHERN NEW ENGLAND THURSDAY
EVENING. BOTH THE ECMWF AND GFS INDICATE SOME LIGHT QPF ASSOCIATED
WITH THE FRONTAL PASSAGE SO THERE IS POTENTIAL FOR SHOWERS WITH THE
FRONT.
FRIDAY AND SATURDAY...HIGH PRESSURE BUILDS IN BEHIND THE BACK DOOR
FRONT. WITH A MORE NORTHERLY FLOW THROUGH MUCH OF THE DAY AND MUCH
COOLER TEMPERATURES TO THE NORTH...EXPECT COOLER THAN SEASONABLE
TEMPS FRIDAY. THEN SATURDAY AS HIGH PRESSURE MOVES AWAY FROM THE
REGION...TEMPERATURES SHOULD MODERATE SOMEWHAT.
SUNDAY AND MONDAY...THE GREATEST DIFFERENCES BETWEEN THE MODELS ARE
IN THIS PERIOD...AS USUAL. HOWEVER...EVEN WITH THIS TIME PERIOD...
THEY ARE IN REMARKABLY GOOD AGREEMENT. ANOTHER COLD FRONT MOVES
THROUGH SOUTHERN NEW ENGLAND WITH LOW PRESSURE IN THE MARITIMES
SUNDAY THEN HIGH PRESSURE BUILDS BACK INTO THE REGION MONDAY.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
18Z UPDATE...
LOW CONFIDENCE FORECAST CONTINUES. FOR THE REMAINDER OF TODAY...
WITH ANY SHRA/TSRA MVFR-IFR IMPACTS ARE ANTICIPATED. OTHERWISE
MVFR-VFR PREVAILS. ISSUANCE OF AWW/S LIKELY NECESSARY INTO THE
EVENING WITH TSRA AND THE EXPECTATION FOR CLOUD TO GROUND
LIGHTNING.
CONDITIONS ARE EXPECTED TO QUIET OVERNIGHT...YET FOG ANTICIPATED
TO BUILD BACK IN...ESPECIALLY ALONG THE SOUTH/SOUTHEAST COAST.
WILL SEE CIGS AND VSBYS LOWER TO IFR-VLIFR. WITH THE APPROACHING
COLD FRONT TOWARDS MORNING...WINDS WILL BACK OUT OF THE WEST AND
CONDITIONS WILL IMPROVE AS CIGS LIFT AND FOG DISSIPATES. BUT THERE
REMAINS A THREAT INTO THE LATE MORNING INTO AFTERNOON HOURS OF
SHRA/TSRA DEVELOPING AGAIN ALONG THE COLD FRONT. MVFR/IFR IMPACTS
ONCE AGAIN WILL BE POSSIBLE...OTHERWISE VFR WITH WESTERLY FLOW
INTO WEDNESDAY MORNING.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. SHRA/TSRA BUILDING
AROUND THE TERMINAL WILL REMAIN A THREAT INTO EVENING.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. A LULL FOR NOW...BUT
EXPECT ACTIVITY SOUTH AND WEST TO BUILD BACK IN LATER THIS
AFTERNOON CONTINUING INTO EVENING. WITH ANY SHRA/TSRA...MVFR-IFR
POSSIBLE.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
MODERATE TO HIGH CONFIDENCE. MAINLY VFR. LOW CONFIDENCE IN ISOLD
SHRA/TSRA THURSDAY RESULTING IN BRIEF MVFR/IFR CONDITIONS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
4 PM UPDATE...
SHOWERS AND THUNDERSTORMS WILL LINGER ACROSS THE WATERS INTO THE
EVENING HOURS AND AROUND MIDNIGHT. MUCH OF THE ACTIVITY SHOULD
DIMINISH TOWARDS MORNING. FOG WILL BE AN ISSUE ALONG THE SOUTH-
SOUTHEAST WATERS WITH VISIBILITIES DOWN TO A QUARTER MILE OR LESS
POSSIBLE.
A SURFACE COLD FRONT WILL APPROACH THE WATERS TOWARDS MIDDAY
ALONG AND AHEAD OF WHICH WILL BE RENEWED CHANCES FOR SHOWERS AND
THUNDERSTORMS ALONG WITH SOUTHWESTERLY WIND GUSTS OF AROUND 20
KTS. STORMS COULD BECOME STRONG TO SEVERE WITH GALE FORCE WIND
GUSTS. SEAS LOCALLY MAY EXCEED 5 FEET WITH STORMS...OTHERWISE STAY
JUST BELOW. WILL SEE ACTIVITY EXIT OUT TO SEA LATE TUESDAY INTO
TUESDAY EVENING...WINDS AND SEAS DIMINISH.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
QUIET BOATING WEATHER EXPECTED WITH WESTERLY WINDS AND SEAS BELOW
SMALL CRAFT CRITERIA.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR MAZ002>021-
026.
NH...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR NHZ011-012-
015.
RI...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR RIZ001>007.
MARINE...NONE.
&&
$$
SYNOPSIS...RLG/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...RLG
AVIATION...RLG/SIPPRELL
MARINE...RLG/SIPPRELL
AREA FORECAST DISCUSSION
NWS ALBANY NY
150 PM EDT MON SEP 2 2013
.SYNOPSIS...
ANOTHER WARM...HUMID AND WET DAY ACROSS THE AREA AS A LOW PRESSURE
SYSTEM APPROACHES FROM THE WEST. THE BEST CHANCES FOR STORMS ARE
EXPECTED THIS AFTERNOON INTO THE EARLY EVENING. SOME STORMS WILL
PRODUCE VERY HEAVY DOWNPOURS. A DRIER AIRMASS WILL BE USHERED IN
LATE TONIGHT AND TUESDAY AS THE SYSTEM`S COLD FRONT MOVES ACROSS
THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM EDT...SCATTERED CONVECTION HAS DEVELOPING AND SHOWING
SOME SIGNS OF TRAINING ACROSS THE CATSKILLS WITH ADDITIONAL MORE
ROBUST CONVECTIVE TRENDS FURTHER UPSTREAM OVER WESTERN NY. WE WILL
KNOCK DOWN POPS FOR A BRIEF TIME THIS AFTERNOON WITH A RAPID
INCREASE TOWARD MID-LATE AFTERNOON AS THE COMBINATION OF UPSTREAM
TROUGH AXIS AND RATHER DIFFUSE SURFACE BOUNDARY APPROACHES. PWATS
REMAIN UP TO 2 INCHES WITH UPSTREAM SBCAPES JUST BELOW 3K J/KG AND
MARGINAL SHEAR PARAMETERS AROUND 20KTS. PER THE HRRR...SEEMS A
SCT-BKN LINE OF CONVECTION WILL DEVELOP AND MOVE ACROSS THE REGION
BUT ITS INTENSITY REMAINS IN QUESTION DUE TO THE CONSIDERABLE CLOUD
COVER THE REGION HAS EXPERIENCED THUS FAR. GOES RSO 1KM VISIBLE
SUGGEST SOME MORE BREAKS INTO THE MOHAWK VALLEY SO WE WILL CONTINUE
TO MONITOR TRENDS VERY CLOSELY. FLOOD WATCHES REMAIN IN EFFECT FOR
THE EASTERN PORTIONS OF THE CWFA.
PREV DISC...
AS OF 1022 AM EDT...MUCH OF THIS MORNINGS SHOWERS AND
THUNDERSTORMS HAVE MOVED EAST OF THE AREA. HOWEVER...THERE IS
STILL A CLUSTER OF CONVECTION WITH HEAVY RAIN OVER DUTCHESS AND
LITCHFIELD COUNTIES LATE THIS MORNING. THIS ACTIVITY IS TIED TO A
SMALL-SCALE UPPER LEVEL DISTURBANCE SEEN WELL ON WATER VAPOR
IMAGERY. THIS AREA OF CONVECTION SHOULD CONTINUE TO SLOWLY MOVE
EASTWARD THROUGH EARLY AFTERNOON.
THEN ATTENTION SHIFTS TO THE WEST...WHERE ADDITIONAL SHOWER AND
THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ACROSS CENTRAL NY
ASSOCIATED WITH THE NEXT UPPER LEVEL DISTURBANCE OVER WESTERN NY
AND A PRE-FRONTAL TROUGH AT THE SURFACE. HI RES MODELS INCLUDING
THE 3KM HRRR AND OUR LOCAL HIRESWRF INDICATE CONVECTION INCREASING
IN COVERAGE BY EARLY TO MID AFTERNOON ACROSS THE AREA AS LARGE
SCALE ASCENT STRENGTHENS.
ONCE AGAIN THE MAIN THREAT WILL BE HEAVY RAINFALL AND POSSIBLE
FLASH FLOODING...AS PWATS ARE STILL RUNNING ANOMALOUSLY HIGH. THE
READING FROM THE 12Z KALB SOUNDING WAS 1.70 INCHES. GENERALLY
TALL/SKINNY CAPE PROFILE FAVORS THE HEAVY RAIN THREAT. DEPENDING
ON HOW MUCH LIMITED SUNSHINE CAN BREAK THROUGH THE CLOUDS...THERE
IS AN ADDITIONAL THREAT FOR STRONG GUSTY WINDS ASSOCIATED WITH
THUNDERSTORMS THIS AFTERNOON INTO THE EVENING. THE BETTER THREAT
AREA APPEARS TO BE WESTERN/CENTRAL NY WHERE MORE CLEARING IS
TAKING PLACE. FOR OUR AREA EXPECTING AROUND 1000-1500 K/KG OF
SBCAPE TO BUILD...WITH DEEP LAYER SHEAR IN THE 25 TO 35 KT
RANGE...WHICH COULD RESULT IN SOME MORE ORGANIZED CLUSTERS OF
STORMS. WILL CONTINUE TO MONITOR TRENDS INTO THE AFTERNOON.
FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE TACONICS...THE
BERKSHIRES...LITCHFIELD COUNTY AND SOUTHERN VERMONT VALID INTO
EARLY THIS EVENING. PORTIONS OF THIS AREA RECEIVED HEAVY RAINFALL
SUNDAY AND AGAIN OVERNIGHT/THIS MORNING MAKING THEM VULNERABLE TO
FLASH FLOODING. HOWEVER....WE CAN NOT RULE OUT THE POSSIBILITY FOR
ISOLATED FLASH FLOODING ACROSS EAST CENTRAL NEW YORK TODAY BUT
FORECAST CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT A WATCH AT THIS
TIME.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE UPPER TROUGH STILL HAS TO SWING THROUGH AND IT WILL DO SO
TUESDAY AND TUESDAY NIGHT FINALLY MOVING OFF TO THE EAST AFTER
MIDNIGHT. EXPECTING SCATTERED SHOWERS ACROSS THE AREA AS THE TROUGH
AXIS APPROACHES. HEIGHTS WILL THEN RISE A BIT LATE TUESDAY NIGHT
INTO WEDNESDAY. HOWEVER...AN UPPER LEVEL LOW WILL DEVELOP OVER
HUDSON BAY CANADA DROPPING A REINFORCING COLD FRONT INTO THE REGION
WEDNESDAY NIGHT.
TEMPERATURES TUESDAY WILL BE SEASONABLY WARM...WITH MUCH MORE
COMFORTABLE DEW POINTS THAN RECENT DAYS...DROPPING INTO THE 50S.
TEMPERATURES WEDNESDAY WILL BE SIMILAR AND EVEN A BIT WARMER THAN
TUESDAY ACROSS THE HIGHER TERRAIN WITH THE HELP OF SOME SUNSHINE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE EXTENDED FORECAST FOLLOWS CLOSELY THE HPC GUIDANCE THIS MORNING
DUE TO THE ACTIVE ONGOING WX. THE MID WEEK INTO NEXT WEEKEND WILL
BE DOMINATED BY A MEAN LONGWAVE TROUGH. THIS WILL PROVIDE THE
REGION WITH A PREVAILING NW FLOW ALOFT AND TEMPS NEAR NORMAL TO
BELOW NORMAL FOR THE STRETCH. HUMIDITY LEVELS WILL BE LOW AND
COMFORTABLE.
THU-FRI...A COLD FRONT DIPS SOUTH OF THE REGION WITH A COOL CANADIAN
AIR MASS BUILDING IN FROM THE GREAT LAKES REGION AND OHIO VALLEY.
H850 TEMPS FALL TO +2C TO +5C ACCORDING THE LATEST GFS THU NIGHT.
MAX TEMPS WILL RANGE FROM THE U50S TO M60S OVER THE SRN DACKS TO
LOWER TO M70S FROM THE CAPITAL REGION SOUTH AND EAST. LOWS WILL BE
IN THE 40S WITH SOME 30S OVER THE DACKS. FRIDAY WILL FEATURE LOTS
OF SUNSHINE AND TEMPS ABOUT 5-7 DEGREES BELOW NORMAL WITH MID AND
U60S OVER THE HILLS AND MTNS...AND L70S IN THE VALLEYS.
FRI NIGHT-SAT...THE SFC HIGH MOVES SOUTH AND EAST OF THE
REGION...AS A WARM FRONT BRIEFLY LIFTS THROUGH WITH LITTLE IF ANY
PCPN. LOWS WILL STILL BE IN THE M40S TO M50S. A COLD FRONT SLIDES
S/SE FROM SRN ONTARIO AND SWERN QUEBEC. THE BEST CHC FOR SHOWERS
WILL BE FROM THE CAPITAL REGION NORTH AND WEST DURING THE DAY...AND
SLIGHT CHC VALUES TO THE SOUTH AND EAST. THE CONVERGENCE WITH THIS
BOUNDARY IS NOT VERY STRONG.
SATURDAY NIGHT INTO SUNDAY...THE COLD FRONT SINKS SOUTH OF THE FCST
AREA WITH A REINFORCING SURGE OF COOL...CANADIAN AIR. A SLIGHT TO
LOW CHC OF SHOWERS LINGERS INTO SUNDAY MORNING. A BROAD ANTICYCLONE
SETTLES OVER NY AND NEW ENGLAND TO CLOSE THE WEEKEND AND OPEN NEXT
WEEK. TEMPS WILL FINISH NEAR SEASONABLE NORMALS.
OVERALL...PCPN LOOKS BELOW NORMAL WITH TEMPS SLIGHTLY BELOW NORMAL
IN THE LONG TERM.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A STRONG UPPER LEVEL LOW AND SURFACE COLD FRONT WILL APPROACH FROM
SOUTHEAST ONTARIO AND SOUTHWEST QUEBEC INTO THIS EVENING...BRINGING
PERIODS OF SHOWERS AND THUNDERSTORMS TO THE TERMINALS.
CONDITIONS ARE MAINLY VFR EARLY THIS AFTERNOON...BUT WITHIN ANY
SHRA/TSRA OCCASIONAL MVFR AND EVEN BRIEF IFR CONDITIONS WILL BE
LIKELY. WITH AT LEAST SCATTERED COVERAGE OF CONVECTION...THERE IS
ENOUGH CONFIDENCE TO MENTION TSRA IN TEMPOS FOR 3-4 HOURS FROM MID
AFTERNOON INTO THE EVENING. HIGHEST PROBABILITY FOR A TSRA IMPACTING
A SPECIFIC TERMINAL IS KPOU...SO WILL MENTION IFR CONDITIONS IN THE
TEMPO THERE.
OTHERWISE...CONVECTION SHOULD DECREASE THIS EVENING AND ESPECIALLY
AFTER DARK WITH LOSS OF INSTABILITY AND THE FRONTAL BOUNDARY MOVING
ACROSS THE AREA. HOWEVER...THERE WILL BE PLENTY OF RESIDUAL
LOW-LEVEL MOISTURE...SO LOW STRATUS AND/OR SOME FOG FORMATION IS
LIKELY. MVFR/IFR CONDITIONS POSSIBLE...WITH THE GREATEST LIKELIHOOD
FOR IFR AT KGFL/KPSF.
VFR CONDITIONS SHOULD RETURN BY LATE TUESDAY MORNING...AS A DRIER
NORTHWEST FLOW DEVELOPS ACROSS THE REGION. THERE IS THE RISK FOR AN
ISOLATED SHOWER AS THE UPPER LEVEL TROUGH AXIS PASSES THROUGH...BUT
COVERAGE IS TOO LOW TO MENTION IN TAFS AT THIS TIME.
SURFACE WINDS WILL BE SOUTHERLY AROUND 5 TO 7 KT INTO THE
EVENING...THEN BECOMING LIGHT AND VARIABLE. WINDS WILL SHIFT TO THE
NORTHWEST AND INCREASE TO AROUND 5 TO 10 KT TUESDAY MORNING. WINDS
WILL BE GUSTY AND ERRATIC IN AND NEAR ANY THUNDERSTORMS.
OUTLOOK...
TUESDAY NIGHT TO FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
WARM...HUMID AND WET WEATHER WILL CONTINUE TODAY. A DRIER AIRMASS
WILL BE USHERED IN LATE TONIGHT INTO TUESDAY AS COLD FRONT MOVES
ACROSS THE REGION.
&&
.HYDROLOGY...
PRECIPITABLE WATER VALUES ARE HIGH CLOSE TO 2 INCHES SO VERY HEAVY
DOWNPOURS WILL OCCUR WITH SOME STORMS. WINDS WILL REMAIN LIGHT
RESULTING IN SLOW MOVEMENT OF THE STORMS.
HAVE DECIDED TO ISSUE A FLASH FLOOD WATCH FOR THE TACONICS...THE
BERKSHIRES...LITCHFIELD COUNTY AND SOUTHERN VERMONT VALID INTO EARLY
THIS EVENING. PORTIONS OF THIS AREA RECEIVED HEAVY RAINFALL SUNDAY
AND AGAIN OVERNIGHT/EARLY THIS MORNING MAKING THEM MORE VULNERABLE
TO FLASH FLOODING. HOWEVER....WE CAN NOT RULE OUT THE POSSIBILITY
FOR ISOLATED FLASH FLOODING ACROSS EAST CENTRAL NEW YORK TODAY BUT
FORECAST CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT A WATCH AT THIS
TIME.
A DRIER AIRMASS WILL FINALLY BE USHERED INTO THE REGION LATE
TONIGHT AND TUESDAY AS COLD FRONT MOVES ACROSS THE REGION.
WIDESPREAD PRECIPITATION IS NOT EXPECTED THIS WEEK AS HIGH PRESSURE
WILL DOMINATE MUCH OF THE TIME. HOWEVER...THERE WILL BE A COUPLE/FEW
FRONTAL PASSAGES WHICH WILL BRING THE THREAT OF SHOWERS TO THE
AREA.
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...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ054-061-
066.
MA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025.
VT...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/JPV/BGM
SHORT TERM...IAA
LONG TERM...WASULA
AVIATION...JPV
FIRE WEATHER...IAA
HYDROLOGY...IAA/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
138 PM EDT MON SEP 2 2013
.SYNOPSIS...
ANOTHER WARM...HUMID AND WET DAY ACROSS THE AREA AS A LOW PRESSURE
SYSTEM APPROACHES FROM THE WEST. THE BEST CHANCES FOR STORMS ARE
EXPECTED THIS AFTERNOON INTO THE EARLY EVENING. SOME STORMS WILL
PRODUCE VERY HEAVY DOWNPOURS. A DRIER AIRMASS WILL BE USHERED IN
LATE TONIGHT AND TUESDAY AS THE SYSTEM`S COLD FRONT MOVES ACROSS
THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1022 AM EDT...MUCH OF THIS MORNINGS SHOWERS AND
THUNDERSTORMS HAVE MOVED EAST OF THE AREA. HOWEVER...THERE IS
STILL A CLUSTER OF CONVECTION WITH HEAVY RAIN OVER DUTCHESS AND
LITCHFIELD COUNTIES LATE THIS MORNING. THIS ACTIVITY IS TIED TO A
SMALL-SCALE UPPER LEVEL DISTURBANCE SEEN WELL ON WATER VAPOR
IMAGERY. THIS AREA OF CONVECTION SHOULD CONTINUE TO SLOWLY MOVE
EASTWARD THROUGH EARLY AFTERNOON.
THEN ATTENTION SHIFTS TO THE WEST...WHERE ADDITIONAL SHOWER AND
THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ACROSS CENTRAL NY
ASSOCIATED WITH THE NEXT UPPER LEVEL DISTURBANCE OVER WESTERN NY
AND A PRE-FRONTAL TROUGH AT THE SURFACE. HI RES MODELS INCLUDING
THE 3KM HRRR AND OUR LOCAL HIRESWRF INDICATE CONVECTION INCREASING
IN COVERAGE BY EARLY TO MID AFTERNOON ACROSS THE AREA AS LARGE
SCALE ASCENT STRENGTHENS.
ONCE AGAIN THE MAIN THREAT WILL BE HEAVY RAINFALL AND POSSIBLE
FLASH FLOODING...AS PWATS ARE STILL RUNNING ANOMALOUSLY HIGH. THE
READING FROM THE 12Z KALB SOUNDING WAS 1.70 INCHES. GENERALLY
TALL/SKINNY CAPE PROFILE FAVORS THE HEAVY RAIN THREAT. DEPENDING
ON HOW MUCH LIMITED SUNSHINE CAN BREAK THROUGH THE CLOUDS...THERE
IS AN ADDITIONAL THREAT FOR STRONG GUSTY WINDS ASSOCIATED WITH
THUNDERSTORMS THIS AFTERNOON INTO THE EVENING. THE BETTER THREAT
AREA APPEARS TO BE WESTERN/CENTRAL NY WHERE MORE CLEARING IS
TAKING PLACE. FOR OUR AREA EXPECTING AROUND 1000-1500 K/KG OF
SBCAPE TO BUILD...WITH DEEP LAYER SHEAR IN THE 25 TO 35 KT
RANGE...WHICH COULD RESULT IN SOME MORE ORGANIZED CLUSTERS OF
STORMS. WILL CONTINUE TO MONITOR TRENDS INTO THE AFTERNOON.
FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE TACONICS...THE
BERKSHIRES...LITCHFIELD COUNTY AND SOUTHERN VERMONT VALID INTO
EARLY THIS EVENING. PORTIONS OF THIS AREA RECEIVED HEAVY RAINFALL
SUNDAY AND AGAIN OVERNIGHT/THIS MORNING MAKING THEM VULNERABLE TO
FLASH FLOODING. HOWEVER....WE CAN NOT RULE OUT THE POSSIBILITY FOR
ISOLATED FLASH FLOODING ACROSS EAST CENTRAL NEW YORK TODAY BUT
FORECAST CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT A WATCH AT THIS
TIME.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE UPPER TROUGH STILL HAS TO SWING THROUGH AND IT WILL DO SO
TUESDAY AND TUESDAY NIGHT FINALLY MOVING OFF TO THE EAST AFTER
MIDNIGHT. EXPECTING SCATTERED SHOWERS ACROSS THE AREA AS THE TROUGH
AXIS APPROACHES. HEIGHTS WILL THEN RISE A BIT LATE TUESDAY NIGHT
INTO WEDNESDAY. HOWEVER...AN UPPER LEVEL LOW WILL DEVELOP OVER
HUDSON BAY CANADA DROPPING A REINFORCING COLD FRONT INTO THE REGION
WEDNESDAY NIGHT.
TEMPERATURES TUESDAY WILL BE SEASONABLY WARM...WITH MUCH MORE
COMFORTABLE DEW POINTS THAN RECENT DAYS...DROPPING INTO THE 50S.
TEMPERATURES WEDNESDAY WILL BE SIMILAR AND EVEN A BIT WARMER THAN
TUESDAY ACROSS THE HIGHER TERRAIN WITH THE HELP OF SOME SUNSHINE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
THE EXTENDED FORECAST FOLLOWS CLOSELY THE HPC GUIDANCE THIS MORNING
DUE TO THE ACTIVE ONGOING WX. THE MID WEEK INTO NEXT WEEKEND WILL
BE DOMINATED BY A MEAN LONGWAVE TROUGH. THIS WILL PROVIDE THE
REGION WITH A PREVAILING NW FLOW ALOFT AND TEMPS NEAR NORMAL TO
BELOW NORMAL FOR THE STRETCH. HUMIDITY LEVELS WILL BE LOW AND
COMFORTABLE.
THU-FRI...A COLD FRONT DIPS SOUTH OF THE REGION WITH A COOL CANADIAN
AIR MASS BUILDING IN FROM THE GREAT LAKES REGION AND OHIO VALLEY.
H850 TEMPS FALL TO +2C TO +5C ACCORDING THE LATEST GFS THU NIGHT.
MAX TEMPS WILL RANGE FROM THE U50S TO M60S OVER THE SRN DACKS TO
LOWER TO M70S FROM THE CAPITAL REGION SOUTH AND EAST. LOWS WILL BE
IN THE 40S WITH SOME 30S OVER THE DACKS. FRIDAY WILL FEATURE LOTS
OF SUNSHINE AND TEMPS ABOUT 5-7 DEGREES BELOW NORMAL WITH MID AND
U60S OVER THE HILLS AND MTNS...AND L70S IN THE VALLEYS.
FRI NIGHT-SAT...THE SFC HIGH MOVES SOUTH AND EAST OF THE
REGION...AS A WARM FRONT BRIEFLY LIFTS THROUGH WITH LITTLE IF ANY
PCPN. LOWS WILL STILL BE IN THE M40S TO M50S. A COLD FRONT SLIDES
S/SE FROM SRN ONTARIO AND SWERN QUEBEC. THE BEST CHC FOR SHOWERS
WILL BE FROM THE CAPITAL REGION NORTH AND WEST DURING THE DAY...AND
SLIGHT CHC VALUES TO THE SOUTH AND EAST. THE CONVERGENCE WITH THIS
BOUNDARY IS NOT VERY STRONG.
SATURDAY NIGHT INTO SUNDAY...THE COLD FRONT SINKS SOUTH OF THE FCST
AREA WITH A REINFORCING SURGE OF COOL...CANADIAN AIR. A SLIGHT TO
LOW CHC OF SHOWERS LINGERS INTO SUNDAY MORNING. A BROAD ANTICYCLONE
SETTLES OVER NY AND NEW ENGLAND TO CLOSE THE WEEKEND AND OPEN NEXT
WEEK. TEMPS WILL FINISH NEAR SEASONABLE NORMALS.
OVERALL...PCPN LOOKS BELOW NORMAL WITH TEMPS SLIGHTLY BELOW NORMAL
IN THE LONG TERM.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A STRONG UPPER LEVEL LOW AND SURFACE COLD FRONT WILL APPROACH FROM
SOUTHEAST ONTARIO AND SOUTHWEST QUEBEC INTO THIS EVENING...BRINGING
PERIODS OF SHOWERS AND THUNDERSTORMS TO THE TERMINALS.
CONDITIONS ARE MAINLY VFR EARLY THIS AFTERNOON...BUT WITHIN ANY
SHRA/TSRA OCCASIONAL MVFR AND EVEN BRIEF IFR CONDITIONS WILL BE
LIKELY. WITH AT LEAST SCATTERED COVERAGE OF CONVECTION...THERE IS
ENOUGH CONFIDENCE TO MENTION TSRA IN TEMPOS FOR 3-4 HOURS FROM MID
AFTERNOON INTO THE EVENING. HIGHEST PROBABILITY FOR A TSRA IMPACTING
A SPECIFIC TERMINAL IS KPOU...SO WILL MENTION IFR CONDITIONS IN THE
TEMPO THERE.
OTHERWISE...CONVECTION SHOULD DECREASE THIS EVENING AND ESPECIALLY
AFTER DARK WITH LOSS OF INSTABILITY AND THE FRONTAL BOUNDARY MOVING
ACROSS THE AREA. HOWEVER...THERE WILL BE PLENTY OF RESIDUAL
LOW-LEVEL MOISTURE...SO LOW STRATUS AND/OR SOME FOG FORMATION IS
LIKELY. MVFR/IFR CONDITIONS POSSIBLE...WITH THE GREATEST LIKELIHOOD
FOR IFR AT KGFL/KPSF.
VFR CONDITIONS SHOULD RETURN BY LATE TUESDAY MORNING...AS A DRIER
NORTHWEST FLOW DEVELOPS ACROSS THE REGION. THERE IS THE RISK FOR AN
ISOLATED SHOWER AS THE UPPER LEVEL TROUGH AXIS PASSES THROUGH...BUT
COVERAGE IS TOO LOW TO MENTION IN TAFS AT THIS TIME.
SURFACE WINDS WILL BE SOUTHERLY AROUND 5 TO 7 KT INTO THE
EVENING...THEN BECOMING LIGHT AND VARIABLE. WINDS WILL SHIFT TO THE
NORTHWEST AND INCREASE TO AROUND 5 TO 10 KT TUESDAY MORNING. WINDS
WILL BE GUSTY AND ERRATIC IN AND NEAR ANY THUNDERSTORMS.
OUTLOOK...
TUESDAY NIGHT TO FRIDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
WARM...HUMID AND WET WEATHER WILL CONTINUE TODAY. A DRIER AIRMASS
WILL BE USHERED IN LATE TONIGHT INTO TUESDAY AS COLD FRONT MOVES
ACROSS THE REGION.
&&
.HYDROLOGY...
PRECIPITABLE WATER VALUES ARE HIGH CLOSE TO 2 INCHES SO VERY HEAVY
DOWNPOURS WILL OCCUR WITH SOME STORMS. WINDS WILL REMAIN LIGHT
RESULTING IN SLOW MOVEMENT OF THE STORMS.
HAVE DECIDED TO ISSUE A FLASH FLOOD WATCH FOR THE TACONICS...THE
BERKSHIRES...LITCHFIELD COUNTY AND SOUTHERN VERMONT VALID INTO EARLY
THIS EVENING. PORTIONS OF THIS AREA RECEIVED HEAVY RAINFALL SUNDAY
AND AGAIN OVERNIGHT/EARLY THIS MORNING MAKING THEM MORE VULNERABLE
TO FLASH FLOODING. HOWEVER....WE CAN NOT RULE OUT THE POSSIBILITY
FOR ISOLATED FLASH FLOODING ACROSS EAST CENTRAL NEW YORK TODAY BUT
FORECAST CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT A WATCH AT THIS
TIME.
A DRIER AIRMASS WILL FINALLY BE USHERED INTO THE REGION LATE
TONIGHT AND TUESDAY AS COLD FRONT MOVES ACROSS THE REGION.
WIDESPREAD PRECIPITATION IS NOT EXPECTED THIS WEEK AS HIGH PRESSURE
WILL DOMINATE MUCH OF THE TIME. HOWEVER...THERE WILL BE A COUPLE/FEW
FRONTAL PASSAGES WHICH WILL BRING THE THREAT OF SHOWERS TO THE AREA.
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...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ054-061-
066.
MA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025.
VT...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/JPV
SHORT TERM...IAA
LONG TERM...WASULA
AVIATION...JPV
FIRE WEATHER...IAA
HYDROLOGY...IAA/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
1022 AM EDT MON SEP 2 2013
.SYNOPSIS...
ANOTHER WARM...HUMID AND WET DAY ACROSS THE AREA AS A LOW PRESSURE
SYSTEM APPROACHES FROM THE WEST. THE BEST CHANCES FOR STORMS ARE
EXPECTED THIS AFTERNOON INTO THE EARLY EVENING. SOME STORMS WILL
PRODUCE VERY HEAVY DOWNPOURS. A DRIER AIRMASS WILL BE USHERED IN
LATE TONIGHT AND TUESDAY AS THE SYSTEM`S COLD FRONT MOVES ACROSS
THE REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1022 AM EDT...MUCH OF THIS MORNINGS SHOWERS AND
THUNDERSTORMS HAVE MOVED EAST OF THE AREA. HOWEVER...THERE IS
STILL A CLUSTER OF CONVECTION WITH HEAVY RAIN OVER DUTCHESS AND
LITCHFIELD COUNTIES LATE THIS MORNING. THIS ACTIVITY IS TIED TO A
SMALL-SCALE UPPER LEVEL DISTURBANCE SEEN WELL ON WATER VAPOR
IMAGERY. THIS AREA OF CONVECTION SHOULD CONTINUE TO SLOWLY MOVE
EASTWARD THROUGH EARLY AFTERNOON.
THEN ATTENTION SHIFTS TO THE WEST...WHERE ADDITIONAL SHOWER AND
THUNDERSTORM ACTIVITY HAS ALREADY DEVELOPED ACROSS CENTRAL NY
ASSOCIATED WITH THE NEXT UPPER LEVEL DISTURBANCE OVER WESTERN NY
AND A PRE-FRONTAL TROUGH AT THE SURFACE. HI RES MODELS INCLUDING
THE 3KM HRRR AND OUR LOCAL HIRESWRF INDICATE CONVECTION INCREASING
IN COVERAGE BY EARLY TO MID AFTERNOON ACROSS THE AREA AS LARGE
SCALE ASCENT STRENGTHENS.
ONCE AGAIN THE MAIN THREAT WILL BE HEAVY RAINFALL AND POSSIBLE
FLASH FLOODING...AS PWATS ARE STILL RUNNING ANOMALOUSLY HIGH. THE
READING FROM THE 12Z KALB SOUNDING WAS 1.70 INCHES. GENERALLY
TALL/SKINNY CAPE PROFILE FAVORS THE HEAVY RAIN THREAT. DEPENDING
ON HOW MUCH LIMITED SUNSHINE CAN BREAK THROUGH THE CLOUDS...THERE
IS AN ADDITIONAL THREAT FOR STRONG GUSTY WINDS ASSOCIATED WITH
THUNDERSTORMS THIS AFTERNOON INTO THE EVENING. THE BETTER THREAT
AREA APPEARS TO BE WESTERN/CENTRAL NY WHERE MORE CLEARING IS
TAKING PLACE. FOR OUR AREA EXPECTING AROUND 1000-1500 K/KG OF
SBCAPE TO BUILD...WITH DEEP LAYER SHEAR IN THE 25 TO 35 KT
RANGE...WHICH COULD RESULT IN SOME MORE ORGANIZED CLUSTERS OF
STORMS. WILL CONTINUE TO MONITOR TRENDS INTO THE AFTERNOON.
FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE TACONICS...THE
BERKSHIRES...LITCHFIELD COUNTY AND SOUTHERN VERMONT VALID INTO
EARLY THIS EVENING. PORTIONS OF THIS AREA RECEIVED HEAVY RAINFALL
SUNDAY AND AGAIN OVERNIGHT/THIS MORNING MAKING THEM VULNERABLE TO
FLASH FLOODING. HOWEVER....WE CAN NOT RULE OUT THE POSSIBILITY FOR
ISOLATED FLASH FLOODING ACROSS EAST CENTRAL NEW YORK TODAY BUT
FORECAST CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT A WATCH AT THIS
TIME.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
THE UPPER TROUGH STILL HAS TO SWING THROUGH AND IT WILL DO SO
TUESDAY AND TUESDAY NIGHT FINALLY MOVING OFF TO THE EAST AFTER
MIDNIGHT. EXPECTING SCATTERED SHOWERS ACROSS THE AREA AS THE TROUGH
AXIS APPROACHES. HEIGHTS WILL THEN RISE A BIT LATE TUESDAY NIGHT
INTO WEDNESDAY. HOWEVER...AN UPPER LEVEL LOW WILL DEVELOP OVER
HUDSON BAY CANADA DROPPING A REINFORCING COLD FRONT INTO THE REGION
WEDNESDAY NIGHT.
TEMPERATURES TUESDAY WILL BE SEASONABLY WARM...WITH MUCH MORE
COMFORTABLE DEW POINTS THAN RECENT DAYS...DROPPING INTO THE 50S.
TEMPERATURES WEDNESDAY WILL BE SIMILAR AND EVEN A BIT WARMER THAN
TUESDAY ACROSS THE HIGHER TERRAIN WITH THE HELP OF SOME SUNSHINE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE EXTENDED FORECAST FOLLOWS CLOSELY THE HPC GUIDANCE THIS MORNING
DUE TO THE ACTIVE ONGOING WX. THE MID WEEK INTO NEXT WEEKEND WILL
BE DOMINATED BY A MEAN LONGWAVE TROUGH. THIS WILL PROVIDE THE
REGION WITH A PREVAILING NW FLOW ALOFT AND TEMPS NEAR NORMAL TO
BELOW NORMAL FOR THE STRETCH. HUMIDITY LEVELS WILL BE LOW AND
COMFORTABLE.
THU-FRI...A COLD FRONT DIPS SOUTH OF THE REGION WITH A COOL CANADIAN
AIR MASS BUILDING IN FROM THE GREAT LAKES REGION AND OHIO VALLEY.
H850 TEMPS FALL TO +2C TO +5C ACCORDING THE LATEST GFS THU NIGHT.
MAX TEMPS WILL RANGE FROM THE U50S TO M60S OVER THE SRN DACKS TO
LOWER TO M70S FROM THE CAPITAL REGION SOUTH AND EAST. LOWS WILL BE
IN THE 40S WITH SOME 30S OVER THE DACKS. FRIDAY WILL FEATURE LOTS
OF SUNSHINE AND TEMPS ABOUT 5-7 DEGREES BELOW NORMAL WITH MID AND
U60S OVER THE HILLS AND MTNS...AND L70S IN THE VALLEYS.
FRI NIGHT-SAT...THE SFC HIGH MOVES SOUTH AND EAST OF THE
REGION...AS A WARM FRONT BRIEFLY LIFTS THROUGH WITH LITTLE IF ANY
PCPN. LOWS WILL STILL BE IN THE M40S TO M50S. A COLD FRONT SLIDES
S/SE FROM SRN ONTARIO AND SWERN QUEBEC. THE BEST CHC FOR SHOWERS
WILL BE FROM THE CAPITAL REGION NORTH AND WEST DURING THE DAY...AND
SLIGHT CHC VALUES TO THE SOUTH AND EAST. THE CONVERGENCE WITH THIS
BOUNDARY IS NOT VERY STRONG.
SATURDAY NIGHT INTO SUNDAY...THE COLD FRONT SINKS SOUTH OF THE FCST
AREA WITH A REINFORCING SURGE OF COOL...CANADIAN AIR. A SLIGHT TO
LOW CHC OF SHOWERS LINGERS INTO SUNDAY MORNING. A BROAD ANTICYCLONE
SETTLES OVER NY AND NEW ENGLAND TO CLOSE THE WEEKEND AND OPEN NEXT
WEEK. TEMPS WILL FINISH NEAR SEASONABLE NORMALS.
OVERALL...PCPN LOOKS BELOW NORMAL WITH TEMPS SLIGHTLY BELOW NORMAL
IN THE LONG TERM.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
A STRONG UPPER LEVEL LOW WILL APPROACH FROM SOUTHEAST ONTARIO AND SW
QUEBEC DURING THE AFTERNOON. A SERIES OF BOUNDARIES ASSOCIATED WITH
THE UPPER LOW WILL IMPACT THE REGION INTO THIS EVENING WITH SHOWERS
AND THUNDERSTORMS.
LOW MVFR/IFR CONDITIONS WILL IMPACT THE TERMINALS THIS MORNING.
SCT-NUMEROUS SHOWERS AND THUNDERSTORMS WILL HAVE THE GREATEST IMPACT
AT KPSF/KALB/KGFL NORTHWARD PRIOR TO NOONTIME.
A SFC TROUGH WILL MOVE THROUGH THE REGION IN THE LATE MORNING INTO
THE EARLY PM...AND A COLD FRONT WILL FOLLOW FOR THE MID PM INTO
THE EARLY EVENING. CONDITIONS WILL BRIEFLY RISE BACK TO HIGH
MVFR/LOW VFR LEVELS BEFORE MORE SHOWERS AND THUNDERSTORMS IMPACT THE
TERMINALS WITH AT LEAST MVFR CONDITIONS. OUR CONFIDENCE WAS NOT
GREAT ENOUGH TO ADD THUNDERSTORMS YET...BUT LATER TAF ISSUANCES WILL
ADDRESS PM THUNDERSTORMS.
HIGH MVFR/VFR CONDITIONS MAY RETURN AFTER 00Z/TUE WITH THE SHOWERS
BEGINNING TO END WITH THE PASSAGE OF THE FIRST COLD FRONT.
HOWEVER...THE SKIES MAY CLEAR ENOUGH WITH MOISTURE LEFT IN THE
BOUNDARY LAYER FOR IFR/MVFR BR/FG AND STRATUS TO FORM AGAIN.
THE WINDS WILL BE LIGHT TO CALM THIS MORNING...THEN INCREASE FROM
THE SOUTH TO SOUTHEAST AT 5 TO 10 MPH BY THE AFTERNOON. THE WINDS
WILL VEER TO THE SOUTH TO SOUTHWEST AT LESS THAN 10 MPH LATE THIS
AFTERNOON INTO THE EARLY EVENING. THE WINDS MAY BE CALM AT MOST OF
THE TAF SITES TOWARDS MIDNIGHT WITH LIGHT WEST WINDS AT KALB.
OUTLOOK...
WED-FRI: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
WARM...HUMID AND WET WEATHER WILL CONTINUE TODAY. A DRIER AIRMASS
WILL BE USHERED IN LATE TONIGHT INTO TUESDAY AS COLD FRONT MOVES
ACROSS THE REGION.
&&
.HYDROLOGY...
PRECIPITABLE WATER VALUES ARE HIGH CLOSE TO 2 INCHES SO VERY HEAVY
DOWNPOURS WILL OCCUR WITH SOME STORMS. WINDS WILL REMAIN LIGHT
RESULTING IN SLOW MOVEMENT OF THE STORMS.
HAVE DECIDED TO ISSUE A FLASH FLOOD WATCH FOR THE TACONICS...THE
BERKSHIRES...LITCHFIELD COUNTY AND SOUTHERN VERMONT VALID INTO EARLY
THIS EVENING. PORTIONS OF THIS AREA RECEIVED HEAVY RAINFALL SUNDAY
AND AGAIN OVERNIGHT/EARLY THIS MORNING MAKING THEM MORE VULNERABLE
TO FLASH FLOODING. HOWEVER....WE CAN NOT RULE OUT THE POSSIBILITY
FOR ISOLATED FLASH FLOODING ACROSS EAST CENTRAL NEW YORK TODAY BUT
FORECAST CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT A WATCH AT THIS
TIME.
A DRIER AIRMASS WILL FINALLY BE USHERED INTO THE REGION LATE
TONIGHT AND TUESDAY AS COLD FRONT MOVES ACROSS THE REGION.
WIDESPREAD PRECIPITATION IS NOT EXPECTED THIS WEEK AS HIGH PRESSURE
WILL DOMINATE MUCH OF THE TIME. HOWEVER...THERE WILL BE A COUPLE/FEW
FRONTAL PASSAGES WHICH WILL BRING THE THREAT OF SHOWERS TO THE AREA.
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...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR CTZ001-013.
NY...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ054-061-
066.
MA...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR MAZ001-025.
VT...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR VTZ013>015.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/JPV
SHORT TERM...IAA
LONG TERM...WASULA
AVIATION...WASULA
FIRE WEATHER...IAA
HYDROLOGY...IAA/WASULA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1215 PM EDT MON SEP 2 2013
..HIGH LIGHTNING RISK THIS AFTERNOON; STREET FLOODING POSSIBLE...
.UPDATE...THUNDERSTORMS WITH A LOT OF LIGHTNING ARE ONGOING ACROSS
SW FLORIDA. WE EXPECT QUICK TSTORM DEVELOPMENT ACROSS THE REST OF
THE INTERIOR AND SOUTHEAST FLORIDA OVER THE NEXT HOUR. LIGHTNING
IS A HIGH RISK TODAY. ALSO, THUNDERSTORMS WILL BE SLOW MOVING AND
PRODUCING TORRENTIAL RAINFALL. HRRR SHOWS SOME LOCALES ACROSS SE
FLORIDA PICKING UP OVER 4" OF RAIN THIS AFTERNOON. THIS SEEMS
PLAUSIBLE GIVEN THE ACTIVE WEATHER EXPECTED AND SLOW STORM
MOVEMENT. PRODUCTS WERE UPDATED ACCORDINGLY WITH THIS POTENTIAL
REFLECTED. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 1104 AM EDT MON SEP 2 2013/
UPDATE...A STORMY LABOR DAY AFTERNOON IS EXPECTED. THE MIAMI
SOUNDING SHOWS A MOIST/UNSTABLE ATMOSPHERE WITH A PWAT OF 1.94
INCHES. LAPSE RATES AREN`T AS STEEP AS THEY WERE YESTERDAY WITH
WARMING ALOFT. THE H5 TEMP HAS WARMED BY ALMOST 2C SINCE
YESTERDAY. HOWEVER, ALREADY CONVECTION IS FIRING UP ALONG THE GULF
COAST SEA BREEZE. ONCE THIS MOVES INLAND AND THE ATLANTIC SEA
BREEZE DEVELOPS, THUNDERSTORMS WILL BECOME MORE WIDESPREAD ACROSS
THE INTERIOR AND EAST COAST. MAY NEED TO INCREASE POPS EVEN MORE.
IF LATEST HRRR IS RIGHT, WIDESPREAD ACTIVITY WOULD DEVELOP. THE
MAIN IMPACTS TODAY WITH THE STORMS WILL BE FREQUENT LIGHTNING
STRIKES AND HEAVY RAIN/POTENTIAL ISOLATED STREET FLOODING DUE TO
SLOW STORM MOTION. THERE IS A LESSER RISK OF STRONG WIND GUSTS
THIS AFTERNOON COMPARED TO YESTERDAY, BUT STILL PRESENT. /GREGORIA
PREV DISCUSSION... /ISSUED 827 AM EDT MON SEP 2 2013/
UPDATE...ACARS DATA SHOWS A SW-W LIGHT STEERING FLOW THROUGH THE
COLUMN. GPS MET DATA SHOWS PWATS IN THE 1.75-1.90 INCH RANGE
ACROSS SOUTH FL. THERE HAS BEEN LITTLE ENVIRONMENTAL CHANGES SINCE
YESTERDAY, SO HAVE INCREASED POPS WITH AN ORIENTATION FAVORING THE
INTERIOR AND EAST COAST...GIVEN THE AFOREMENTIONED STEERING FLOW.
NUMEROUS ACTIVITY HAS DEVELOPED OVER THE PAST FEW DAYS AND SEE NO
REASON TO DEVIATE FROM THIS TODAY WITH NUMEROUS THUNDERSTORMS
DEVELOPING INTERIOR AND ACROSS THE EAST COAST METROPOLITAN AREAS
JUST INLAND FROM THE COAST. /GREGORIA
PREV DISCUSSION... /ISSUED 730 AM EDT MON SEP 2 2013/
AVIATION...
MAINLY VFR CONDITIONS SHOULD PREVAIL. LIGHT AND VARIABLE WINDS
THIS MORNING WILL BECOME EASTERLY AT 5-10 KNOTS THIS AFTERNOON.
CONDITIONS ARE SIMILAR TO YESTERDAY...SO KEPT VCTS AFTER 16Z FOR
THE EAST COAST TERMINALS...EXCEPT KPBI. A FEW SHOWERS WERE NEAR
KAPF THIS MORNING...BUT THESE WILL DISSIPATE OVER THE NEXT COUPLE
OF HOURS. THE GULF COAST SEA BREEZE IS EXPECTED TO DEVELOP BY
EARLY AFTERNOON...AND SHOWERS AND STORMS SHOULD MOVE EAST OF KAPF.
SHOWERS AND STORMS ARE FORECAST TO DIMINISH IN THE EARLY
EVENING...WITH LIGHT AND VARIABLE WINDS AGAIN OVERNIGHT.
PREV DISCUSSION... /ISSUED 359 AM EDT MON SEP 2 2013/
DISCUSSION...
NO MAJOR SYNOPTIC SCALE CHANGES EXPECTED ACROSS SOUTH FLORIDA
THROUGH THE WEEK.
FLOW IS EXPECTED TO BE LIGHT THROUGH THE FIRST HALF OF THE WEEK AS
MID LEVEL RIDGING BUILDS ACROSS THE FLORIDA PENINSULA FROM THE
ATLANTIC. THIS SHOULD ALLOW FOR SEA BREEZE/OUTFLOW BOUNDARY
INTERACTIONS TO INDUCE AFTERNOON AND EARLY EVENING SHOWER AND
THUNDERSTORMS MAINLY ACROSS THE INTERIOR AND GULF COASTAL AREAS.
HOWEVER THE RIDGING SHOULD ALSO KEEP THE MID LEVELS OF THE
ATMOSPHERE WEAKLY CAPPED AND IS DEPICTED IN MODEL SOUNDINGS. THIS
SHOULD INHIBIT DEEP VERTICAL DEVELOPMENT OF AFTERNOON
THUNDERSTORMS. HEAT INDEX VALUES ARE ALSO EXPECTED TO BE ON THE
RISE THROUGH MIDWEEK AS A RESULT OF THE STRONGER RIDGING. BY
WEDNESDAY...MAXIMUM HEAT INDEX VALUES SHOULD BE AROUND 100 DEGREES
ACROSS THE EAST COAST METRO AREAS AND BETWEEN 105 AND 109 DEGREES
ACROSS INTERIOR COLLIER COUNTY.
EASTERLY FLOW SHOULD PREVAIL AGAIN BY THURSDAY AND REMAIN THROUGH
THE END OF THE WEEK. AT THIS TIME THE FLOW DOES NOT APPEAR TO BE
STRONG ENOUGH TO COUNTERACT THE DEVELOPMENT OF A GULF COAST SEA
BREEZE. THIS SHOULD KEEP MOST OF THE AFTERNOON CONVECTION TO MAINLY
THE INTERIOR AND GULF COAST.
THERE IS CURRENTLY A DISORGANIZED AREA OF CONVECTION ACROSS THE
LESSER ANTILLES THAT THE NATIONAL HURRICANE CENTER GIVES A 40
PERCENT CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE DURING THE NEXT
48 HOURS AND A 50 PERCENT CHANCE DURING THE NEXT 5 DAYS. IT IS
CURRENTLY MOVING WEST-NORTHWEST AT ABOUT 10 MPH. CURRENT OPERATIONAL
MODELS BRING THIS SYSTEM ACROSS HISPANIOLA AS AN OPEN WAVE LATE IN
THE WEEK AND INTO THE WEEKEND.
AVIATION...
VFR CONDITIONS EXPECTED. VCTS ADDED AT AROUND 16-18Z AT ALL
TERMINALS. EASTERLY FLOW WILL PREVAIL ACROSS THE AREA...SLIGHTLY
INCREASING IN SPEED IN THE AFTERNOON. CURRENT GUIDANCE KEEPS
DEPICTING VCTS AFTER 18Z AT ALL TERMINALS...AND DUE TO SIMILAR
WEATHER CONDITIONS THAN PREVIOUS DAYS...WILL EXPECT THIS ACTIVITY
TO FORM. WEST COAST SEA BREEZE EXPECTED TO PUSH INLAND BY
16Z...WHICH WILL ALSO HELP IN THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THROUGH THE AFTERNOON AND EVENING. ALL ACTIVITY WILL
POSSIBLY DISSIPATE BY 00Z.
MARINE...
GENERALLY EAST TO SOUTHEAST WINDS AT LESS THAN 10 KNOTS WILL
PREVAIL ACROSS THE ATLANTIC WATERS THROUGH MIDWEEK WITH
CORRESPONDING SEAS AT 2 FEET OR LESS. FLOW IS EXPECTED TO BECOME
EASTERLY AND INCREASE SLIGHTLY THROUGH THE LATTER HALF OF THE WEEK
WITH SEAS ONLY IN THE 1 TO 3 FOOT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 77 89 78 / 80 50 30 20
FORT LAUDERDALE 89 79 90 80 / 60 50 30 20
MIAMI 91 78 90 79 / 80 50 30 20
NAPLES 89 75 90 77 / 60 40 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
1104 AM EDT MON SEP 2 2013
...NUMEROUS THUNDERSTORMS DEVELOPING INTERIOR-EAST COAST METRO,
SOME WITH FREQUENT LIGHTNING/LOCALLY HEAVY RAINFALL...
.UPDATE...A STORMY LABOR DAY AFTERNOON IS EXPECTED. THE MIAMI
SOUNDING SHOWS A MOIST/UNSTABLE ATMOSPHERE WITH A PWAT OF 1.94
INCHES. LAPSE RATES AREN`T AS STEEP AS THEY WERE YESTERDAY WITH
WARMING ALOFT. THE H5 TEMP HAS WARMED BY ALMOST 2C SINCE
YESTERDAY. HOWEVER, ALREADY CONVECTION IS FIRING UP ALONG THE GULF
COAST SEA BREEZE. ONCE THIS MOVES INLAND AND THE ATLANTIC SEA
BREEZE DEVELOPS, THUNDERSTORMS WILL BECOME MOVE WIDESPREAD ACROSS
THE INTERIOR AND EAST COAST. MAY NEED TO INCREASE POPS EVEN MORE.
IF LATEST HRRR IS RIGHT, WIDESPREAD ACTIVITY WOULD DEVELOP. THE
MAIN IMPACTS TODAY WITH THE STORMS WILL BE FREQUENT LIGHTNING
STRIKES AND HEAVY RAIN/POTENTIAL ISOLATED STREET FLOODING DUE TO
SLOW STORM MOTION. THERE IS A LESSER RISK OF STRONG WIND GUSTS
THIS AFTERNOON COMPARED TO YESTERDAY, BUT STILL PRESENT.
/GREGORIA
&&
.PREV DISCUSSION... /ISSUED 827 AM EDT MON SEP 2 2013/
UPDATE...ACARS DATA SHOWS A SW-W LIGHT STEERING FLOW THROUGH THE
COLUMN. GPS MET DATA SHOWS PWATS IN THE 1.75-1.90 INCH RANGE
ACROSS SOUTH FL. THERE HAS BEEN LITTLE ENVIRONMENTAL CHANGES SINCE
YESTERDAY, SO HAVE INCREASED POPS WITH AN ORIENTATION FAVORING THE
INTERIOR AND EAST COAST...GIVEN THE AFOREMENTIONED STEERING FLOW.
NUMEROUS ACTIVITY HAS DEVELOPED OVER THE PAST FEW DAYS AND SEE NO
REASON TO DEVIATE FROM THIS TODAY WITH NUMEROUS THUNDERSTORMS
DEVELOPING INTERIOR AND ACROSS THE EAST COAST METROPOLITAN AREAS
JUST INLAND FROM THE COAST. /GREGORIA
PREV DISCUSSION... /ISSUED 730 AM EDT MON SEP 2 2013/
AVIATION...
MAINLY VFR CONDITIONS SHOULD PREVAIL. LIGHT AND VARIABLE WINDS
THIS MORNING WILL BECOME EASTERLY AT 5-10 KNOTS THIS AFTERNOON.
CONDITIONS ARE SIMILAR TO YESTERDAY...SO KEPT VCTS AFTER 16Z FOR
THE EAST COAST TERMINALS...EXCEPT KPBI. A FEW SHOWERS WERE NEAR
KAPF THIS MORNING...BUT THESE WILL DISSIPATE OVER THE NEXT COUPLE
OF HOURS. THE GULF COAST SEA BREEZE IS EXPECTED TO DEVELOP BY
EARLY AFTERNOON...AND SHOWERS AND STORMS SHOULD MOVE EAST OF KAPF.
SHOWERS AND STORMS ARE FORECAST TO DIMINISH IN THE EARLY
EVENING...WITH LIGHT AND VARIABLE WINDS AGAIN OVERNIGHT.
PREV DISCUSSION... /ISSUED 359 AM EDT MON SEP 2 2013/
DISCUSSION...
NO MAJOR SYNOPTIC SCALE CHANGES EXPECTED ACROSS SOUTH FLORIDA
THROUGH THE WEEK.
FLOW IS EXPECTED TO BE LIGHT THROUGH THE FIRST HALF OF THE WEEK AS
MID LEVEL RIDGING BUILDS ACROSS THE FLORIDA PENINSULA FROM THE
ATLANTIC. THIS SHOULD ALLOW FOR SEA BREEZE/OUTFLOW BOUNDARY
INTERACTIONS TO INDUCE AFTERNOON AND EARLY EVENING SHOWER AND
THUNDERSTORMS MAINLY ACROSS THE INTERIOR AND GULF COASTAL AREAS.
HOWEVER THE RIDGING SHOULD ALSO KEEP THE MID LEVELS OF THE
ATMOSPHERE WEAKLY CAPPED AND IS DEPICTED IN MODEL SOUNDINGS. THIS
SHOULD INHIBIT DEEP VERTICAL DEVELOPMENT OF AFTERNOON
THUNDERSTORMS. HEAT INDEX VALUES ARE ALSO EXPECTED TO BE ON THE
RISE THROUGH MIDWEEK AS A RESULT OF THE STRONGER RIDGING. BY
WEDNESDAY...MAXIMUM HEAT INDEX VALUES SHOULD BE AROUND 100 DEGREES
ACROSS THE EAST COAST METRO AREAS AND BETWEEN 105 AND 109 DEGREES
ACROSS INTERIOR COLLIER COUNTY.
EASTERLY FLOW SHOULD PREVAIL AGAIN BY THURSDAY AND REMAIN THROUGH
THE END OF THE WEEK. AT THIS TIME THE FLOW DOES NOT APPEAR TO BE
STRONG ENOUGH TO COUNTERACT THE DEVELOPMENT OF A GULF COAST SEA
BREEZE. THIS SHOULD KEEP MOST OF THE AFTERNOON CONVECTION TO MAINLY
THE INTERIOR AND GULF COAST.
THERE IS CURRENTLY A DISORGANIZED AREA OF CONVECTION ACROSS THE
LESSER ANTILLES THAT THE NATIONAL HURRICANE CENTER GIVES A 40
PERCENT CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE DURING THE NEXT
48 HOURS AND A 50 PERCENT CHANCE DURING THE NEXT 5 DAYS. IT IS
CURRENTLY MOVING WEST-NORTHWEST AT ABOUT 10 MPH. CURRENT OPERATIONAL
MODELS BRING THIS SYSTEM ACROSS HISPANIOLA AS AN OPEN WAVE LATE IN
THE WEEK AND INTO THE WEEKEND.
AVIATION...
VFR CONDITIONS EXPECTED. VCTS ADDED AT AROUND 16-18Z AT ALL
TERMINALS. EASTERLY FLOW WILL PREVAIL ACROSS THE AREA...SLIGHTLY
INCREASING IN SPEED IN THE AFTERNOON. CURRENT GUIDANCE KEEPS
DEPICTING VCTS AFTER 18Z AT ALL TERMINALS...AND DUE TO SIMILAR
WEATHER CONDITIONS THAN PREVIOUS DAYS...WILL EXPECT THIS ACTIVITY
TO FORM. WEST COAST SEA BREEZE EXPECTED TO PUSH INLAND BY
16Z...WHICH WILL ALSO HELP IN THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THROUGH THE AFTERNOON AND EVENING. ALL ACTIVITY WILL
POSSIBLY DISSIPATE BY 00Z.
MARINE...
GENERALLY EAST TO SOUTHEAST WINDS AT LESS THAN 10 KNOTS WILL
PREVAIL ACROSS THE ATLANTIC WATERS THROUGH MIDWEEK WITH
CORRESPONDING SEAS AT 2 FEET OR LESS. FLOW IS EXPECTED TO BECOME
EASTERLY AND INCREASE SLIGHTLY THROUGH THE LATTER HALF OF THE WEEK
WITH SEAS ONLY IN THE 1 TO 3 FOOT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 77 89 78 / 50 30 30 20
FORT LAUDERDALE 89 79 90 80 / 40 30 30 20
MIAMI 91 78 90 79 / 50 30 30 20
NAPLES 89 75 90 77 / 20 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
951 AM EDT MON SEP 2 2013
.UPDATE...
TODAY WILL LIKELY BE SIMILAR TO YESTERDAY WITH ISOLATED SHOWERS
BEGINNING ALONG THE GULF COAST EARLY BUT NOT ADVANCING VERY FAR
INLAND UNTIL LATER IN THE MORNING. THE HRRR DEPICTS THE ACTIVITY
SPREADING NORTHEASTWARD EARLY AFTN AT SAME TIME SOME SHOWER/
STORMS BEGIN DEVELOPING ALONG THE ATLC SEABREEZE...WHICH WILL
REMAIN PINNED NEAR THE COAST DUE TO THE OFFSHORE FLOW. EXPECT
GUSTY WINDS AND TORRENTIAL RAINFALL FROM THE STRONGER STORMS.
&&
.AVIATION...
VFR IS EXPECTED EXCEPT IN AND NEAR TSRA. WILL SHOW VCTS AFTER 19Z
UNTIL AROUND 00Z.
&&
.MARINE...
BUOYS ARE AVERAGING WINDS 10-15 KTS WITH LOWER SPEEDS NEARSHORE
DUE TO SW OFFSHORE FLOW. A TIGHTER GRADIENT OVER GA WATERS HAS
KEPT WINDS HIGHER THERE AND GRAYS REEF TO OUR NORTH IS 16G17KT.
SEAS ARE RUNNING 1-3 FT. NO CHANGES EXPECTED IN THE UPDATE.
ANOTHER NOCTURNAL SURGE IS FORECAST WITH POSSIBLE SCEC CONDITIONS
FOR OFFSHORE LEGS.
RIP CURRENTS: LOW RISK DUR TO AN OFFSHORE FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 91 72 93 73 / 50 40 40 30
SSI 89 76 90 77 / 30 30 30 30
JAX 92 72 93 75 / 40 30 40 30
SGJ 90 74 91 75 / 40 30 40 40
GNV 92 71 92 73 / 30 20 40 30
OCF 92 71 93 73 / 20 10 30 20
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
TRABERT/GUILLET
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
135 AM EDT MON SEP 2 2013
.PREV DISCUSSION... /ISSUED 928 PM EDT SUN SEP 1 2013/
UPDATE...NEXT IN A SERIES OF SHORTWAVES IN NORTHWEST FLOW ALOFT
PUSHED THROUGH THE FORECAST AREA THIS EVENING WITH A NEARLY
CONTINUOUS LINE AFFECTING THE ATLANTA METRO AND POINTS SOUTHWARD.
ONLY ISOLATED REPORTS OF TREES DOWN HOWEVER AS ACTIVITY WAS
LARGELY BENIGN DESPITE ITS ORGANIZED STRUCTURE. ACTIVITY HAS
SUBSIDED SIGNIFICANTLY BUT ADDITIONAL SHORTWAVE ENERGY UPSTREAM
ALREADY PRODUCING ACTIVITY OVER TENNESSEE AT THIS HOUR. HRRR AND
LOCAL WRF BOTH SHOWING POSSIBLE DEVELOPMENT INTO THE OVERNIGHT
HOURS BUT DIFFER ON EXACT TIMING. FOR NOW...WILL LEAVE GRIDS AS
THEY STAND WHICH BRINGS CHANCE POPS BACK TO THE NORTH JUST PRIOR
TO DAYBREAK. NO CHANGES PLANNED AT THIS TIME.
DEESE
PREV DISCUSSION... /ISSUED 755 PM EDT SUN SEP 1 2013/
PREV DISCUSSION... /ISSUED 339 PM EDT SUN SEP 1 2013/
SHORT TERM /TONIGHT THROUGH MONDAY/...
UPPER TROUGH DEEPENS OVER THE GREAT LAKES THROUGH TOMORROW. SEVERAL
RIPPLES NOTED IN THE UPPER LEVEL FLOW TODAY ENHANCING CONVECTION.
SHORT TERM HIRES MODELS NOT HANDLING CURRENT CONVECTION WELL. GOOD
MOISTURE...AND INSTABILITY NOTED ACROSS THE FORECAST AREA...CAPES
APPROACHING 2000...AS AN OUT FLOW BOUNDARY FROM THIS MORNINGS
CONVECTION ACROSS NORTH GA...AIDED IN THE DEVELOPMENT OF A LINE OF
SHOWERS AND THUNDERSTORMS FROM CARROLLTON TO ATLANTA TO ATHENS.
THIS LINE WILL SAG SLOWLY SOUTHWARD THROUGH THIS EVENING. HRRR
HINTING AT ANOTHER LINE DEVELOPING OVER EASTER AL JUST BEFORE
SUNSET IMPACTING PORTIONS OF WEST AND CENTRAL GA THROUGH LATE
EVENING...WITH THE AREA ALREADY WORKED OVER AM NOT BITING ON THIS
SOLUTION AT THIS TIME. WILL CONTINUE TO SHOW CONVECTION SHIFTING
TO THE SOUTH SIDE OF ATL TO AHN AFTER 4-5PM AND IMPACTING CSG-MCN
BETWEEN 6-9 PM.
MODELS SHOWING MOISTURE AND INSTABILITY LINGERING OVERNIGHT...AND
ISOLATED STORMS WILL CONTINUE TO BE POSSIBLE. ECMWF/GFS/NAM ALL
SHOWING MCS POSSIBLE BY 12Z MONDAY NOW AND HAVE CONTINUED CHANCE
POPS ACROSS NORTH GEORGIA TO ACCOUNT FOR THE FEATURE. WEAK SURFACE
FRONT CONTINUES TO APPROACH NORTH GEORGIA TOMORROW AND WITH GOOD
MOISTURE AND INCREASING INSTABILITY ONCE AGAIN EXPECT SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA ON MONDAY.
CONTINUED TO USE A BIAS CORRECTED BLEND OF GUIDANCE TEMPERATURES
ACROSS THE AREA THROUGH THE SHORT TERM PERIODS...ALTHOUGH MAX
TEMPERATURES MONDAY WILL BE HIGHLY DEPENDENT ON THE AMOUNT OF LOW
LEVEL CLOUDS THAT ARE ABLE TO DEVELOP IN RAIN SOAKED AREAS TONIGHT.
ATWELL
LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
ONLY MINOR TWEAKS MADE TO THE EXTENDED. DID RAISE TEMPERATURES FOR
SATURDAY/SUNDAY A DEGREE OR SO BUT STILL LOOKING LIKE THE COOLEST
DAYS OF EXTENDED PERIOD.
PREV DISCUSSION... /ISSUED 324 AM EDT SUN SEP 1 2013/
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
THE EXTENDED BEGINS WITH AN UPPER LOW OVER SOUTHERN ONTARIO...
TROUGHING DOWN THE EASTERN THIRD OF THE U.S...WITH THE ASSOCIATED
COLD FRONT PUSHING THROUGH THE SOUTHEAST. PRECIP CHANCES CONTINUE
ACROSS THE STATE MONDAY NIGHT BUT AS THE FRONT PUSHES TOWARD THE
COAST TUESDAY AND TUESDAY NIGHT...DRIER AIR FILTERS IN BEHIND IT
AND PUSHES PRECIP CHANCES INTO CENTRAL AND SOUTH GEORGIA. DRIEST
DAY LOOKS TO BE WEDNESDAY AS THE TROUGH AXIS SHIFTS EAST OFF THE
COAST AND HIGH PRESSURE DOMINATES MOST OF THE STATE. HOWEVER...ON
THURSDAY ANOTHER SHORTWAVE ROUNDS THE BASE OF THE TROUGH AND LOOKS
TO PROVIDE ENOUGH LIFT THAT WHEN COMBINED WITH OROGRAPHIC LIFTING
IS ENOUGH TO WARRANT SLIGHT TO LOW CHANCE POPS IN THE NORTHEAST
MOUNTAINS. ECMWF IS A LITTLE STRONGER WITH THIS SHORTWAVE
INITIALLY BUT BOTH MODELS IN REASONABLE AGREEMENT WITH THIS
FEATURE ON FRIDAY. AS WE PUSH INTO THE WEEKEND...THE GFS IS
DEFINITELY THE WETTER OF THE TWO MODELS SO COMPROMISED ON THIS
UNCERTAINTY BY PAINTING GENERALLY SLIGHT CHANCE POPS ACROSS THE
AREA ON SATURDAY.
AS FOR TEMPS...TUESDAY WILL CONTINUE THE TREND OF ABOVE-NORMAL
TEMPS...AND EVEN WITH THE FRONTAL PASSAGE TEMPS WILL ONLY DROP A
COUPLE OF DEGREES BUT SHOULD BE NEAR SEASONAL NORMALS. THE MORE
NOTICEABLE CHANGE WILL BE IN OVERNIGHT LOWS...LIKELY DROPPING AT
LEAST 5 DEGREES BETWEEN MONDAY NIGHT AND WEDNESDAY NIGHT. SATURDAY
IS A BIT FAR OUT THERE BUT WITH THE INFLUENCE OF THE STRONG
SHORTWAVE /INCREASED CLOUDINESS/...RIGHT NOW THAT LOOKS TO BE THE
COOLEST DAY OF THE PERIOD.
TDP
&&
.AVIATION...
06Z UPDATE...
SEEING SOME PATCHY MVFR FOG AT TAF TIME...THIS SHOULD INCREASE IN
COVERAGE THROUGH THE MORNING HOURS AND EXPECT LOW MVFR CIGS TO
DEVELOP AS WELL. CIGS SHOULD BEGIN LIFTING AFTER SUNRISE...WITH
TSRA CHANCES INCREASING DURING THE AFTERNOON. FOR NOW LEFT PROB30
IN BUT DEPENDING ON HOW TRENDS GO THIS MORNING MAY NEED TO
INCREASE WORDING TO PREVAILING. SOME HINTS AT MVFR CIGS AGAIN
TUESDAY MORNING BUT DRIER AIR WILL BE MOVING IN SO NOT CONFIDENT
IN THAT AND HAVE ONLY HINTED WITH BKN030 FOR ATL AT THIS TIME.
WIND SW TO W THROUGH THE PERIOD...LIGHT OVERNIGHT AND 4-8KT DURING
THE DAY...EXCEPT GUSTY IN THUNDERSTORMS.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON CIGS/VSBY THIS MORNING.
HIGH ON OCCURRENCE OF CONVECTION...MEDIUM ON IMPACTS TO ATL.
LOW ON CIGS TUESDAY MORNING.
HIGH ON WINDS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 90 72 90 68 / 60 40 30 20
ATLANTA 90 74 90 69 / 60 40 30 20
BLAIRSVILLE 84 68 84 62 / 60 60 20 20
CARTERSVILLE 89 71 90 66 / 70 50 20 10
COLUMBUS 93 74 90 71 / 50 40 40 20
GAINESVILLE 88 73 89 67 / 60 50 30 20
MACON 91 72 91 69 / 40 30 40 20
ROME 90 72 90 66 / 70 60 20 10
PEACHTREE CITY 90 71 89 67 / 50 40 30 20
VIDALIA 93 74 90 73 / 40 30 40 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....ATWELL
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1100 PM MDT SUN SEP 1 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 207 PM MDT SUN SEP 1 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW RIDGE BEGINNING TO
RETREAT TOWARD THE FOUR CORNERS REGION WITH POSITIVELY TILTED
TROUGH MIGRATING INTO THE NORTHERN GREAT LAKES REGION. STRONG
SUBSIDENCE IS EVIDENT ACROSS THE NORTHERN PLAINS...AND IS
BEGINNING TO OVERSPREAD OUR CWA FROM THE NORTH-NORTHEAST. AT THE
SURFACE HIGH PRESSURE HAS SETTLED OVER OUR CWA WITH COLD FRONT NOW
ALONG FRONT RANGE EXTENDING SOUTH ACROSS TEXAS PANHANDLE.
THERE HAVE BEEN A FEW LIGHT SHOWERS SLOWLY MOVING ACROSS THE
PLAINS OF EASTERN COLORADO AND LATEST RAP/HRRR SHOW THIS ACTIVITY
FALLING APART THROUGH SUNRISE. AT THIS POINT I AM NOT CONFIDENT WE
WILL SEE ANY MEASURABLE PRECIP OUT OF THIS WITH STABLE/DRY AIR
SPREADING WEST...SO I WILL KEEP MENTION OUT THROUGH THE REMAINDER
OF THE AFTERNOON. WITH STABLE AIR MASS IN PLACE AND SUBSIDENCE
BUILDING IN ALOFT...I AM ANTICIPATING DRY CONDITIONS THROUGH
MONDAY.
REGARDING TEMPS...COOLER AIR MASS REMAINS IN PLACE OVERNIGHT...AND
WITH LOW TD VALUES (45-50F) ADVECTING SOUTH THROUGH THIS EVENING
AND CLEAR/CALM CONDITIONS WE SHOULD SEE VERY GOOD RADIATIONAL
COOLING. I TRIMMED TEMPS A LITTLE WITH LOWS AT SOME LOCATIONS IN
THE LOW 50S. H5 RIDGE WILL BEGIN TO BUILD BACK TO THE EAST MONDAY
AND LEE TROUGH WILL BEGIN TO STRENGTHEN. WE SHOULD SEE WAA ALOFT
WITH UNIDIRECTIONAL SOUTHERLY FLOW...AND HIGHS ABOUT 3-4F WARMER
THAN TODAY (UPPER 80S/NEAR 90F).
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 221 PM MDT SUN SEP 1 2013
FROM MONDAY NIGHT THROUGH SATURDAY...THE UPPER HIGH PRESSURE
CENTER REMAINS OVER THE CENTRAL ROCKIES AND CENTRAL HIGH PLAINS
REGIONS. BY NEXT SUNDAY...THE UPPER LOW CENTER THAT HAS BEEN SLOWLY
MOVING INTO THE PACIFIC NORTHWEST MOVES ACROSS THE NORTHERN
ROCKIES AND NORTHERN HIGH PLAINS...PUSHING THE UPPER TROUGH AXIS
FURTHER EAST OVER THE PLAINS AND WESTERN GREAT LAKES
REGIONS AND TURNING THE FLOW ALOFT TO THE SOUTHWEST ACROSS THE
FORECAST AREA.
THE SURFACE HIGH PRESSURE AREA IN PLACE OVER THE PLAINS STATES
MOVES FURTHER TO THE EAST AS THE SURFACE TROUGH MOVES INTO
POSITION NEAR THE EASTERN COLORADO BORDER BY WEDNESDAY MORNING. A
WEAK SURFACE TROUGH REMAINS NEARLY STATIONARY OVER THE EASTERN
COLORADO BORDER THROUGH SUNDAY WITH MAINLY WESTERLY FLOW ALOFT
OVER THE ROCKIES. DURING THIS TIME...ISOLATED SHOWERS AND THUNDERSTORMS
ARE EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN TO THE WEST EACH
AFTERNOON WITH A STRAY STORM OR TWO MOVING INTO THE WESTERN
PORTION OF THE FORECAST AREA LATE EACH DAY. OTHERWISE...HAVE KEPT
THE EXTENDED FORECAST PERIOD DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM MDT SUN SEP 1 2013
FOR KGLD AND KMCK VFR THROUGH THE PERIOD. SFC HIGH TO MOVE THROUGH
SUNRISE PROVIDING FOR LIGHT/VARIABLE WINDS. PRESSURE GRADIENT
INCREASES DURING THE DAY MONDAY LEADING TO SOUTHERLY WINDS GUSTING
NEAR 25KTS AT KGLD BY 17Z AND CONTINUING THROUGH THE REST OF THE
TAF PERIOD BEFORE LOSING THE GUSTINESS AFTER 01Z. FOR KMCK
SOUTH/SOUTHEAST WIND AROUND 10KTS EXPECTED BY 16Z AND CONTINUING
THROUGH THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...99
AREA FORECAST DISCUSSION
NWS JACKSON KY
605 PM EDT MON SEP 2 2013
.UPDATE...
ISSUED AT 605 PM EDT MON SEP 2 2013
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. INCREASED THE CHANCES OF PRECIPITATION 10-20 PERCENT BASED
ON WHAT WAS SHOWING UP ON THE RADAR AND THE OUTPUT FROM THE RAPID
REFRESH MODEL. ALSO HAVE THE PRECIPITATION ENDING TONIGHT AND NOT
EXTEND INTO TUESDAY. THE NAM BUFR WAS SHOWING A DECREASE IN MID LEVEL
MOISTURE AND INCREASED CAPPING STARTING TO OCCUR OVER THE NEXT FEW
HOURS. THIS SHOULD HELP THE LOW THE THREAT FOR STRONG TO SEVERE
THUNDERSTORMS BY 8 PM. THE REST OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 338 PM EDT MON SEP 2 2013
ISOLATED SHOWERS AND THUNDERSTORMS WERE AFFECTING THE AREA AT MID
AFTERNOON. THEY WERE INCREASING IN COVERAGE ALONG A LINE FROM
LOUISVILLE KY TO ZANESVILLE OH...ALONG AND AHEAD OF A COLD FRONT.
HAVE FOLLOWED THE FORECAST OF THE HRRR MODEL THROUGH THIS EVENING...
SHOWING THE GREATEST CONCENTRATION OF CONVECTION ALONG AND JUST AHEAD
OF THE COLD FRONT AS IT MOVES SE...WITH A BIT OF A DROP OFF IN
ACTIVITY AFTER NIGHTFALL. THIS PLACES HIGHEST POPS IN OUR NW COUNTIES
DURING THE LATE AFTERNOON AND EARLY EVENING. HAVE KEPT THEM IN THE
HIGH CHANCE RANGE THERE...AND USED POPS LOWER IN THE CHANCE RANGE
DURING THE NIGHT AS THE FRONT MOVES FURTHER SE. A FEW STRAGGLING
SHOWERS COULD BE LINGERING NEAR THE VA BORDER ON TUESDAY MORNING AS
THE FRONT LEAVES. HIGH PRESSURE BUILDING IN FROM THE NW BEHIND THE
FRONT WILL BRING IN A DRIER AIR MASS...WITH SKIES BECOMING MOSTLY
CLEAR FROM NW TO SE LATE TONIGHT AND TUESDAY AND PERSISTING THROUGH
TUESDAY NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 338 PM EDT MON SEP 2 2013
THE UPPER LEVEL PATTERN WILL START OFF AMPLIFIED WITH A LARGE RIDGE
CENTERED ACROSS THE ROCKIES...AN UPPER LOW CENTERED OFF THE PACIFIC
NORTHWEST COAST...AND DEEP TROUGHING EXTENDED FROM EASTERN CANADA
DOWN THROUGH NEW ENGLAND. THE MODELS ARE IN GOOD AGREEMENT...WITH A
GRADUAL DAMPENING TO TAKE PLACE IN GENERAL ACROSS THE WESTERN HALF
OF THE CONUS AS THE PACIFIC NORTHWEST UPPER LOW ADVANCES EAST ON THE
NORTHERN PERIPHERY OF THE RIDGE...WEAKENING BOTH FEATURES IN THE
PROCESS. THE TROUGHING TO THE EAST WILL BE SLOWER TO PULL OUT UNTIL
THE ROCKIES RIDGE SLIDES EAST INTO THE MISSISSIPPI VALLEY BY THE END
OF THE WEEK AND INTO EARLY NEXT WEEK.
ALL OF THIS WILL RESULT IN AN EXTENDED PERIOD OF GENERALLY DRY
WEATHER ACROSS EASTERN KENTUCKY...WITH SURFACE HIGH PRESSURE
REMAINING PARKED ACROSS THE AREA THROUGH FRIDAY...BEFORE IT BECOMES
MORE CONGEALED OFF OF THE THE EASTERN SEABOARD FOR THE WEEKEND AND
EARLY NEXT WEEK. ENOUGH MOISTURE MAY THEN RETURN TO JUSTIFY HANGING
ONTO SOME SLIGHT CHANCE POPS ALONG THE SOUTHEAST TERRAIN SATURDAY
THROUGH MONDAY.
FOR TEMPERATURES...LOWS WILL START OUT IN THE 50S THROUGH THE END OF
THE WORK WEEK...WITH HIGHS MAINLY IN THE LOW TO MID 80S. WARMER AND
MORE HUMID AIR WILL THEN GRADUALLY INCREASE ACROSS THE
AREA...ALTHOUGH PEAK DEW POINTS IN THE AFTERNOON LOOK TO HOLD IN THE
LOW TO MID 60S...SO NOT AS BALMY AS WHAT WE HAVE BEEN ACCUSTOMED TO
OVER THE PAST SEVERAL DAYS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 605 PM EDT MON SEP 2 2013
LOCALIZED MVFR POSSIBLE WITH SHOWERS AND THUNDERSTORMS MOVING ACROSS
THE AREA AHEAD OF AND ALONG WITH THE FRONT. SOME TEMPO IFR IS ALSO
POSSIBLE WITH THE HEAVIEST OF THE STORMS. SHOWERS WILL DIE OUT
OVERNIGHT AFTER A COLD FRONT PASSES. THE GREATEST UNCERTAINTY IS WITH
THE FOG DEVELOPMENT TONIGHT. THERE IS SOME DRY AIR BEHIND THE
FRONT...HOWEVER THE ATMOSPHERE MAY BE ABLE TO DECOUPLE BEFORE THE DRY
AIR MIXES DOWN TO THE SURFACE. ANOTHER VARIABLE IS HOW MUCH RAIN IS
GOING TO FALL AS THE FRONT PASSES. THE MORE RAIN...THE GREATER THE
CHANCE FOR SEEING SOME VFR. WILL BE STAYING WITH MVFR WITH THE
PASSING SHOWERS AND NEAR DAWN WITH THE MIST. AFTER 13Z...IT SHOULD BE
VFR FOR QUITE A WHILE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...HAL
LONG TERM...GEOGERIAN
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
338 PM EDT MON SEP 2 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 338 PM EDT MON SEP 2 2013
ISOLATED SHOWERS AND THUNDERSTORMS WERE AFFECTING THE AREA AT MID
AFTERNOON. THEY WERE INCREASING IN COVERAGE ALONG A LINE FROM
LOUISVILLE KY TO ZANESVILLE OH...ALONG AND AHEAD OF A COLD FRONT.
HAVE FOLLOWED THE FORECAST OF THE HRRR MODEL THROUGH THIS EVENING...
SHOWING THE GREATEST CONCENTRATION OF CONVECTION ALONG AND JUST AHEAD
OF THE COLD FRONT AS IT MOVES SE...WITH A BIT OF A DROP OFF IN
ACTIVITY AFTER NIGHTFALL. THIS PLACES HIGHEST POPS IN OUR NW COUNTIES
DURING THE LATE AFTERNOON AND EARLY EVENING. HAVE KEPT THEM IN THE
HIGH CHANCE RANGE THERE...AND USED POPS LOWER IN THE CHANCE RANGE
DURING THE NIGHT AS THE FRONT MOVES FURTHER SE. A FEW STRAGGLING
SHOWERS COULD BE LINGERING NEAR THE VA BORDER ON TUESDAY MORNING AS
THE FRONT LEAVES. HIGH PRESSURE BUILDING IN FROM THE NW BEHIND THE
FRONT WILL BRING IN A DRIER AIR MASS...WITH SKIES BECOMING MOSTLY
CLEAR FROM NW TO SE LATE TONIGHT AND TUESDAY AND PERSISTING THROUGH
TUESDAY NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 338 PM EDT MON SEP 2 2013
THE UPPER LEVEL PATTERN WILL START OFF AMPLIFIED WITH A LARGE RIDGE
CENTERED ACROSS THE ROCKIES...AN UPPER LOW CENTERED OFF THE PACIFIC
NORTHWEST COAST...AND DEEP TROUGHING EXTENDED FROM EASTERN CANADA
DOWN THROUGH NEW ENGLAND. THE MODELS ARE IN GOOD AGREEMENT...WITH A
GRADUAL DAMPENING TO TAKE PLACE IN GENERAL ACROSS THE WESTERN HALF
OF THE CONUS AS THE PACIFIC NORTHWEST UPPER LOW ADVANCES EAST ON THE
NORTHERN PERIPHERY OF THE RIDGE...WEAKENING BOTH FEATURES IN THE
PROCESS. THE TROUGHING TO THE EAST WILL BE SLOWER TO PULL OUT UNTIL
THE ROCKIES RIDGE SLIDES EAST INTO THE MISSISSIPPI VALLEY BY THE END
OF THE WEEK AND INTO EARLY NEXT WEEK.
ALL OF THIS WILL RESULT IN AN EXTENDED PERIOD OF GENERALLY DRY
WEATHER ACROSS EASTERN KENTUCKY...WITH SURFACE HIGH PRESSURE
REMAINING PARKED ACROSS THE AREA THROUGH FRIDAY...BEFORE IT BECOMES
MORE CONGEALED OFF OF THE THE EASTERN SEABOARD FOR THE WEEKEND AND
EARLY NEXT WEEK. ENOUGH MOISTURE MAY THEN RETURN TO JUSTIFY HANGING
ONTO SOME SLIGHT CHANCE POPS ALONG THE SOUTHEAST TERRAIN SATURDAY
THROUGH MONDAY.
FOR TEMPERATURES...LOWS WILL START OUT IN THE 50S THROUGH THE END OF
THE WORK WEEK...WITH HIGHS MAINLY IN THE LOW TO MID 80S. WARMER AND
MORE HUMID AIR WILL THEN GRADUALLY INCREASE ACROSS THE
AREA...ALTHOUGH PEAK DEW POINTS IN THE AFTERNOON LOOK TO HOLD IN THE
LOW TO MID 60S...SO NOT AS BALMY AS WHAT WE HAVE BEEN ACCUSTOMED TO
OVER THE PAST SEVERAL DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 217 PM EDT MON SEP 2 2013
LOCALIZED MVFR DUE MAINLY TO CEILINGS WAS PRESENT AT THE START OF THE
PERIOD...BUT ONGOING OVERALL IMPROVEMENT WAS OCCURRING. MOSTLY VFR
PREVAILED. ISOLATED SHOWERS WERE DEVELOPING AND WILL PERSIST THROUGH
THE AFTERNOON...BRINGING VERY LOCALIZED RESTRICTIONS. A FEW OF THEM
MAY GROW TALL ENOUGH TO PRODUCE LIGHTNING. SHOWERS WILL DIE OUT
OVERNIGHT AFTER A COLD FRONT PASSES. FOG IS EXPECTED TO DEVELOP
OVERNIGHT...EVENTUALLY BRINGING WIDESPREAD IFR. FOG AND LOW CLOUDS
WILL LIFT AND DISSIPATE ON TUESDAY MORNING...LEAVING VFR BY THE END
OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HAL
LONG TERM...GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
217 PM EDT MON SEP 2 2013
.UPDATE...
ISSUED AT 217 PM EDT MON SEP 2 2013
UPDATED FORECAST GRIDS BASED ON OBSERVED TRENDS...WITH LITTLE IMPACT
ON THE OVERALL FORECAST.
UPDATE ISSUED AT 1108 AM EDT MON SEP 2 2013
LOW CLOUDS DEVELOPED AND BECAME MUCH MORE PREVALENT THIS MORNING THAN
WAS FORECAST. THIS SLOWED THE WARM-UP A BIT AND WILL DELAY DEVELOPMENT
OF SURFACE BASED DEEP CONVECTION.
UPDATE ISSUED AT 730 AM EDT MON SEP 2 2013
RAN A DATA LOAD AND BLEND TO MATCH UP THE CURRENT OBS AND TRENDS WITH
THE GRIDS. OTHERWISE...THE FORECAST IS ON TRACK AND UPDATES HAVE BEEN
SENT TO THE NDFD/WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 2 2013
07Z SFC ANALYSIS SHOWS LOW PRESSURE MOVING THROUGH THE OHIO VALLEY
WITH A COLD FRONT PRESSING INTO KENTUCKY FROM THE NORTHWEST. ON THE
OTHER SIDE OF THAT BOUNDARY COOLER AND MUCH DRIER AIR IS FOUND. EAST
KENTUCKY IS ON THE OPPOSITE SIDE GIVING US ANOTHER MUGGY AND MILD
NIGHT WITH TEMPS AND DEW POINTS WITHIN A FEW DEGREES OF 70. PLENTY OF
LOW LEVEL MOISTURE IS KEEPING SOME LOW LEVEL CLOUDS AROUND IN
ADDITION TO SUPPORTING THE DEVELOPMENT OF PATCHY VALLEY FOG...BUT THE
CONVECTION HAS REMAINED AT BAY.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM. THEY
ALL TAKE A DECENT...FOR LATE SUMMER...TROUGH THROUGH THE GREAT LAKES
AND OHIO VALLEY FROM TODAY INTO TUESDAY. THIS WILL SUPPORT LOW
HEIGHTS AND SHORT WAVE ENERGY PASSING THROUGH THE REGION TODAY AND
TONIGHT. THE TROUGH AXIS DOES GO THROUGH EAST KENTUCKY BY TUESDAY
MORNING...THOUGH...AND THIS WILL BE FOLLOWED BY RISING HEIGHTS IN
THE WAKE OF THE TROUGH. THE MESOSCALE WILL STILL DOMINATE OUR WEATHER
WITH DIFFERENTIAL HEATING AND OUTFLOW BOUNDARIES HELPING TO DRIVE THE
CONVECTION AHEAD OF THE COLD FRONT THAT WILL PUSH THROUGH EAST
KENTUCKY LATER TONIGHT. ACCORDINGLY...HAVE LEANED TOWARD THE HIGHER
RESOLUTION NAM12 FOR WEATHER DETAILS...BUT MORE BROAD BRUSHED WITH
THE SPECIFICS...ALONG WITH USING THE HRRR FOR THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A RECHARGING OF THE AIR MASS OVER EAST
KENTUCKY TODAY WITH BUILDING INSTABILITY AHEAD OF THAT FRONT. THIS
SHOULD YIELD SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA BY
MID AFTERNOON. GRADUALLY THE CONVECTION WILL SHRINK SOUTHEAST DURING
THE EVENING HOURS AS THE FRONT PUSHES THE DEEPER MOISTURE OUT OF THE
AREA. AS A RESULT...HAVE MAXED OUT POPS NEAR 00Z FOR THE AREA WITH A
TAPERING FROM NORTHWEST TO SOUTHEAST THEREAFTER. COOLER AIR FILTERING
INTO THE STATE IN THE WAKE OF THE FRONT WILL LEAD TO LOWER TEMPS IN
THE NORTHWEST PARTS OF THE CWA BY TUESDAY MORNING...THOUGH MUGGY
VALUES WILL REMAIN TO THE SOUTH AND EAST. DRIER AIR TAKES OVER ON
TUESDAY BRINGING A NICE CHANGE...MAKING FOR A PLEASANTLY DRY AND
COOLER DAY.
AGAIN USED THE CONSSHORT AND ITS BC VERSION FOR A STARTING POINT WITH
THE DEW POINT AND WIND GRIDS...RESPECTIVELY...UNTIL 00Z TUESDAY...
FOLLOWED THE CONSALL FOR THE REST. FOR TEMPS...ADJUSTED THE CONSALL
FOR SOME MINOR TERRAIN ENHANCEMENTS IN THE LOWS TONIGHT WITH THE
HOURLY DIURNAL CURVE DERIVED FROM THE NAM12. AS FOR POPS...ENDED UP
CLOSER TO THE WETTER MAV GUIDANCE TODAY...AND SIMILAR TO BOTH
TONIGHT...THEN DRY ON TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 2 2013
NOT A LOT OF CHANGE FOR THE EXTENDED PERIOD. TUESDAY NIGHT/WEDNESDAY
SHOULD BEGIN WITH UPPER LEVEL TROUGHING AND SURFACE HIGH PRESSURE IN
PLACE WITH LIGHT WINDS. THE ONLY MOISTURE AVAILABLE IN THE
ATMOSPHERE WILL BE IN THE UPPER LEVELS WEDNESDAY AFTERNOON...WITH
ABUNDANT DRYING BELOW. AS A RESULT...SOME CIRRUS CLOUDS WILL BE
PRESENT...BUT OTHERWISE WEATHER WILL BE QUITE BENIGN. COOLER AND
DRIER AIR FLOWING IN FROM CANADA WILL KEEP HIGH TEMPS AND HUMIDITY
AT BAY.
FOR THURSDAY...MUCH OF THE SAME IS EXPECTED THROUGH THE FIRST HALF
OF THE DAY. THEN...AS WAS MENTIONED IN PREVIOUS FORECAST...AN
IMPULSE DROPPING INTO A LARGE UPPER TROUGH OVER THE NE CONUS AND SE
CANADA WILL SEND ANOTHER COLD FRONT SOUTH TOWARD THE LOCAL AREA
THURSDAY AFTERNOON OR THURSDAY NIGHT. HOWEVER... VIRTUALLY NO LOW
LEVEL MOISTURE RETURN IS EXPECTED...AND THE FRONT SHOULD BE DYING
OUT AS IT APPROACHES...WITH ALMOST NO IMPACT ON OUR LOCAL
WEATHER. AS THE FRONT DIES...HIGH PRESSURE DROPPING IN BEHIND IT
WILL MERGE WITH HIGH PRESSURE ORIGINALLY TO THE SOUTH OF THE
FRONT...WITH THE LOCAL RESULT BEING DRY WEATHER UNDER ITS DOMINANCE
THROUGH AT LEAST FRIDAY NIGHT.
A WEAK DISTURBANCE WILL TRY TO MOVE THROUGH THE OHIO VALLEY AND ERN
KY LATE IN THE WEEKEND. HOWEVER AT THIS POINT...LATEST GFS SOUNDINGS
ARE STILL LOOKING RATHER LACKLUSTER FOR ANY WIDESPREAD PRECIP
CHANCES. THE GFS IS STILL TRYING TO PINPOINT SOME AFTERNOON
CONVECTION OVER THE HIGHER APPALACHIAN TERRAIN THROUGH THE
WEEKEND...REACHING INTO THE FAR SE COALFIELDS OF KY. THE ECMWF HAS
THE SAME IDEA...BUT CONTINUES TO KEEP ALL PRECIP CHANCES TO OUR SE
OVER THE HIGHER APPALACHIAN TERRAIN. ALL THINGS CONSIDERED...WITH
LITTLE AGREEMENT OR SYNOPTIC SUPPORT...WILL CONTINUE WITH ONLY
SLIGHT CHANCE POPS AT BEST FOR THE FAR SE COUNTIES DURING THE
WEEKEND. ELSEWHERE...THE RETURN OF MORE SRLY FLOW WILL ALLOW
TEMPERATURES TO INCREASE SLIGHTLY THROUGHOUT THE WEEKEND...REACHING
THE MID AND UPPER 80S. HUMIDITY VALUES ON THE OTHER HAND WILL REMAIN
AT BAY...KEEPING CONDITIONS WARM BUT PLEASANT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 217 PM EDT MON SEP 2 2013
LOCALIZED MVFR DUE MAINLY TO CEILINGS WAS PRESENT AT THE START OF THE
PERIOD...BUT ONGOING OVERALL IMPROVEMENT WAS OCCURRING. MOSTLY VFR
PREVAILED. ISOLATED SHOWERS WERE DEVELOPING AND WILL PERSIST THROUGH
THE AFTERNOON...BRINGING VERY LOCALIZED RESTRICTIONS. A FEW OF THEM
MAY GROW TALL ENOUGH TO PRODUCE LIGHTNING. SHOWERS WILL DIE OUT
OVERNIGHT AFTER A COLD FRONT PASSES. FOG IS EXPECTED TO DEVELOP
OVERNIGHT...EVENTUALLY BRINGING WIDEPSREAD IFR. FOG AND LOW CLOUDS
WILL LIFT AND DISSIPATE ON TUESDAY MORNING...LEAVING VFR BY THE END
OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1239 PM CDT Mon Sep 2 2013
.UPDATE...
ISSUED AT 1239 PM CDT MON SEP 2 2013
The aviation section has been updated for the 18Z TAF issuance.
&&
.SHORT TERM...(Today through Wednesday)
ISSUED AT 345 AM CDT MON SEP 2 2013
Cold front early this a.m. was approaching the NW part of our CWFA.
Near calm and saturated surface conditions allowing for areas of
fog especially SRN IL / SEMO where temps crossed over and are in the
upper 60s. Nothing on radar to speak of. Will keep conditions
convection free through the early morning hours. By 15-16z, the
NAM and HRRR drop the front to about the Ohio River with
instability developing ahead of it. Cannot rule out isolated
convection along and ahead of the front mainly over WKY late
morning through the afternoon, given the weak convergence, slight
steepening of mid level lapse rates and modest surface based
instability. Should anything get going, that chance will shift
south and east through late afternoon, followed by a gradual
lowering of humidity from the NW in the wake of the front.
Quiet, cooler weather tonight through Wednesday as high pressure
takes control and builds southward. For temps we used a blend of
MOS and bias corrected model input.
.LONG TERM...(Wednesday night through Monday)
ISSUED AT 345 AM CDT MON SEP 2 2013
At this time, the extended forecast period is a dry forecast. A
westward tilted ridge of high pressure with height persists over the
WFO PAH forecast area, with scant low level moisture available. The
only "ripple" in the forecast late next Sunday into Sunday night,
when there is a slightly troughiness that develops along the east
side of the mid-upper level ridge. However, given that this is such
a low PoP event in the first place, confidence is pretty low for any
measurable precipitation.
With northwest flow aloft east of the upper ridge and little in the
way of any significant changes in thickness values, kept
temperatures in the middle 80s to around 90 for nearly all of the
forecast period.
&&
.AVIATION...
ISSUED AT 1239 PM CDT MON SEP 2 2013
The cold front is dragging its heels across the area and waslocated
near the Ohio River from KPAH to KEVV at 17Z. The front will make
gradual progress through the afternoon with a west northwest wind
developing at all sites by 21Z. Near and ahead of the front a
thick cu field has developed with some MVFR ceilings possible at
all sites except KCGI for the next hour or two. The MVFR ceilings
should lift/scatter once the front moves through a given area.
For tonight, dry and cool surface high pressure will build across
the region, which should prevent fog development. Some lower VFR
ceilings will be possible through the night, especially at KEVV
and KOWB. A modest north northeast wind will mix down throughout
the area by mid-morning Tuesday. There is some signal for a thick
cu field to develop in the east on Tuesday, but any ceilings
should be VFR.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS JACKSON KY
1108 AM EDT MON SEP 2 2013
.UPDATE...
ISSUED AT 1108 AM EDT MON SEP 2 2013
LOW CLOUDS DEVELOPED AND BECAME MUCH MORE PREVALENT THIS MORNING THAN
WAS FORECAST. THIS SLOWED THE WARM-UP A BIT AND WILL DELAY DEVELOPMENT
OF SURFACE BASED DEEP CONVECTION.
UPDATE ISSUED AT 730 AM EDT MON SEP 2 2013
RAN A DATA LOAD AND BLEND TO MATCH UP THE CURRENT OBS AND TRENDS WITH
THE GRIDS. OTHERWISE...THE FORECAST IS ON TRACK AND UPDATES HAVE BEEN
SENT TO THE NDFD/WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 2 2013
07Z SFC ANALYSIS SHOWS LOW PRESSURE MOVING THROUGH THE OHIO VALLEY
WITH A COLD FRONT PRESSING INTO KENTUCKY FROM THE NORTHWEST. ON THE
OTHER SIDE OF THAT BOUNDARY COOLER AND MUCH DRIER AIR IS FOUND. EAST
KENTUCKY IS ON THE OPPOSITE SIDE GIVING US ANOTHER MUGGY AND MILD
NIGHT WITH TEMPS AND DEW POINTS WITHIN A FEW DEGREES OF 70. PLENTY OF
LOW LEVEL MOISTURE IS KEEPING SOME LOW LEVEL CLOUDS AROUND IN
ADDITION TO SUPPORTING THE DEVELOPMENT OF PATCHY VALLEY FOG...BUT THE
CONVECTION HAS REMAINED AT BAY.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM. THEY
ALL TAKE A DECENT...FOR LATE SUMMER...TROUGH THROUGH THE GREAT LAKES
AND OHIO VALLEY FROM TODAY INTO TUESDAY. THIS WILL SUPPORT LOW
HEIGHTS AND SHORT WAVE ENERGY PASSING THROUGH THE REGION TODAY AND
TONIGHT. THE TROUGH AXIS DOES GO THROUGH EAST KENTUCKY BY TUESDAY
MORNING...THOUGH...AND THIS WILL BE FOLLOWED BY RISING HEIGHTS IN
THE WAKE OF THE TROUGH. THE MESOSCALE WILL STILL DOMINATE OUR WEATHER
WITH DIFFERENTIAL HEATING AND OUTFLOW BOUNDARIES HELPING TO DRIVE THE
CONVECTION AHEAD OF THE COLD FRONT THAT WILL PUSH THROUGH EAST
KENTUCKY LATER TONIGHT. ACCORDINGLY...HAVE LEANED TOWARD THE HIGHER
RESOLUTION NAM12 FOR WEATHER DETAILS...BUT MORE BROAD BRUSHED WITH
THE SPECIFICS...ALONG WITH USING THE HRRR FOR THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A RECHARGING OF THE AIR MASS OVER EAST
KENTUCKY TODAY WITH BUILDING INSTABILITY AHEAD OF THAT FRONT. THIS
SHOULD YIELD SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA BY
MID AFTERNOON. GRADUALLY THE CONVECTION WILL SHRINK SOUTHEAST DURING
THE EVENING HOURS AS THE FRONT PUSHES THE DEEPER MOISTURE OUT OF THE
AREA. AS A RESULT...HAVE MAXED OUT POPS NEAR 00Z FOR THE AREA WITH A
TAPERING FROM NORTHWEST TO SOUTHEAST THEREAFTER. COOLER AIR FILTERING
INTO THE STATE IN THE WAKE OF THE FRONT WILL LEAD TO LOWER TEMPS IN
THE NORTHWEST PARTS OF THE CWA BY TUESDAY MORNING...THOUGH MUGGY
VALUES WILL REMAIN TO THE SOUTH AND EAST. DRIER AIR TAKES OVER ON
TUESDAY BRINGING A NICE CHANGE...MAKING FOR A PLEASANTLY DRY AND
COOLER DAY.
AGAIN USED THE CONSSHORT AND ITS BC VERSION FOR A STARTING POINT WITH
THE DEW POINT AND WIND GRIDS...RESPECTIVELY...UNTIL 00Z TUESDAY...
FOLLOWED THE CONSALL FOR THE REST. FOR TEMPS...ADJUSTED THE CONSALL
FOR SOME MINOR TERRAIN ENHANCEMENTS IN THE LOWS TONIGHT WITH THE
HOURLY DIURNAL CURVE DERIVED FROM THE NAM12. AS FOR POPS...ENDED UP
CLOSER TO THE WETTER MAV GUIDANCE TODAY...AND SIMILAR TO BOTH
TONIGHT...THEN DRY ON TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 2 2013
NOT A LOT OF CHANGE FOR THE EXTENDED PERIOD. TUESDAY NIGHT/WEDNESDAY
SHOULD BEGIN WITH UPPER LEVEL TROUGHING AND SURFACE HIGH PRESSURE IN
PLACE WITH LIGHT WINDS. THE ONLY MOISTURE AVAILABLE IN THE
ATMOSPHERE WILL BE IN THE UPPER LEVELS WEDNESDAY AFTERNOON...WITH
ABUNDANT DRYING BELOW. AS A RESULT...SOME CIRRUS CLOUDS WILL BE
PRESENT...BUT OTHERWISE WEATHER WILL BE QUITE BENIGN. COOLER AND
DRIER AIR FLOWING IN FROM CANADA WILL KEEP HIGH TEMPS AND HUMIDITY
AT BAY.
FOR THURSDAY...MUCH OF THE SAME IS EXPECTED THROUGH THE FIRST HALF
OF THE DAY. THEN...AS WAS MENTIONED IN PREVIOUS FORECAST...AN
IMPULSE DROPPING INTO A LARGE UPPER TROUGH OVER THE NE CONUS AND SE
CANADA WILL SEND ANOTHER COLD FRONT SOUTH TOWARD THE LOCAL AREA
THURSDAY AFTERNOON OR THURSDAY NIGHT. HOWEVER... VIRTUALLY NO LOW
LEVEL MOISTURE RETURN IS EXPECTED...AND THE FRONT SHOULD BE DYING
OUT AS IT APPROACHES...WITH ALMOST NO IMPACT ON OUR LOCAL
WEATHER. AS THE FRONT DIES...HIGH PRESSURE DROPPING IN BEHIND IT
WILL MERGE WITH HIGH PRESSURE ORIGINALLY TO THE SOUTH OF THE
FRONT...WITH THE LOCAL RESULT BEING DRY WEATHER UNDER ITS DOMINANCE
THROUGH AT LEAST FRIDAY NIGHT.
A WEAK DISTURBANCE WILL TRY TO MOVE THROUGH THE OHIO VALLEY AND ERN
KY LATE IN THE WEEKEND. HOWEVER AT THIS POINT...LATEST GFS SOUNDINGS
ARE STILL LOOKING RATHER LACKLUSTER FOR ANY WIDESPREAD PRECIP
CHANCES. THE GFS IS STILL TRYING TO PINPOINT SOME AFTERNOON
CONVECTION OVER THE HIGHER APPALACHIAN TERRAIN THROUGH THE
WEEKEND...REACHING INTO THE FAR SE COALFIELDS OF KY. THE ECMWF HAS
THE SAME IDEA...BUT CONTINUES TO KEEP ALL PRECIP CHANCES TO OUR SE
OVER THE HIGHER APPALACHIAN TERRAIN. ALL THINGS CONSIDERED...WITH
LITTLE AGREEMENT OR SYNOPTIC SUPPORT...WILL CONTINUE WITH ONLY
SLIGHT CHANCE POPS AT BEST FOR THE FAR SE COUNTIES DURING THE
WEEKEND. ELSEWHERE...THE RETURN OF MORE SRLY FLOW WILL ALLOW
TEMPERATURES TO INCREASE SLIGHTLY THROUGHOUT THE WEEKEND...REACHING
THE MID AND UPPER 80S. HUMIDITY VALUES ON THE OTHER HAND WILL REMAIN
AT BAY...KEEPING CONDITIONS WARM BUT PLEASANT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 740 AM EDT MON SEP 2 2013
THE LOWER CIGS HAVE NOW MOVED OFF TO THE EAST SO VFR CONDITIONS
SHOULD PREVAIL FOR THE BULK OF THE PERIOD. THERE REMAINS TOO MUCH
UNCERTAINTY WITH TIMING AND COVERAGE OF ANY FRESH CONVECTION LATER
TODAY TO GO ANY MORE SPECIFIC THAN JUST A VCTS AT THE TAF SITES
THROUGH THE DAY. ACCOMPANYING THE STORMS COULD BE MVFR CIGS AND VIS.
THE STORM THREAT SHOULD END FROM NORTHWEST TO SOUTHEAST ACROSS THE
AREA BETWEEN 00 AND 02Z. SOME MVFR FOG COULD DEVELOP AROUND 08Z
TONIGHT AT LOZ...BUT THE OTHER SITES WILL LIKELY REMAIN CLEAR.
OUTSIDE OF ANY STORMS...WINDS WILL BE LIGHT AND VARIABLE...THOUGH
FAVORING THE WEST DURING THE AFTERNOON AND EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
740 AM EDT MON SEP 2 2013
.UPDATE...
ISSUED AT 730 AM EDT MON SEP 2 2013
RAN A DATA LOAD AND BLEND TO MATCH UP THE CURRENT OBS AND TRENDS WITH
THE GRIDS. OTHERWISE...THE FORECAST IS ON TRACK AND UPDATES HAVE BEEN
SENT TO THE NDFD/WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 2 2013
07Z SFC ANALYSIS SHOWS LOW PRESSURE MOVING THROUGH THE OHIO VALLEY
WITH A COLD FRONT PRESSING INTO KENTUCKY FROM THE NORTHWEST. ON THE
OTHER SIDE OF THAT BOUNDARY COOLER AND MUCH DRIER AIR IS FOUND. EAST
KENTUCKY IS ON THE OPPOSITE SIDE GIVING US ANOTHER MUGGY AND MILD
NIGHT WITH TEMPS AND DEWPOINTS WITHIN A FEW DEGREES OF 70. PLENTY OF
LOW LEVEL MOISTURE IS KEEPING SOME LOW LEVEL CLOUDS AROUND IN
ADDITION TO SUPPORTING THE DEVELOPMENT OF PATCHY VALLEY FOG...BUT THE
CONVECTION HAS REMAINED AT BAY.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM. THEY
ALL TAKE A DECENT...FOR LATE SUMMER...TROUGH THROUGH THE GREAT LAKES
AND OHIO VALLEY FROM TODAY INTO TUESDAY. THIS WILL SUPPORT LOW
HEIGHTS AND SHORT WAVE ENERGY PASSING THROUGH THE REGION TODAY AND
TONIGHT. THE TROUGH AXIS DOES GO THROUGH EAST KENTUCKY BY TUESDAY
MORNING...THOUGH...AND THIS WILL BE FOLLOWED BY RISING HEIGHTS IN
THE WAKE OF THE TROUGH. THE MESOSCALE WILL STILL DOMINATE OUR WEATHER
WITH DIFFERENTIAL HEATING AND OUTFLOW BOUNDARIES HELPING TO DRIVE THE
CONVECTION AHEAD OF THE COLD FRONT THAT WILL PUSH THROUGH EAST
KENTUCKY LATER TONIGHT. ACCORDINGLY...HAVE LEANED TOWARD THE HIGHER
RESOLUTION NAM12 FOR WEATHER DETAILS...BUT MORE BROAD BRUSHED WITH
THE SPECIFICS...ALONG WITH USING THE HRRR FOR THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A RECHARGING OF THE AIR MASS OVER EAST
KENTUCKY TODAY WITH BUILDING INSTABILITY AHEAD OF THAT FRONT. THIS
SHOULD YIELD SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA BY
MID AFTERNOON. GRADUALLY THE CONVECTION WILL SHRINK SOUTHEAST DURING
THE EVENING HOURS AS THE FRONT PUSHES THE DEEPER MOISTURE OUT OF THE
AREA. AS A RESULT...HAVE MAXED OUT POPS NEAR 00Z FOR THE AREA WITH A
TAPERING FROM NORTHWEST TO SOUTHEAST THEREAFTER. COOLER AIR FILTERING
INTO THE STATE IN THE WAKE OF THE FRONT WILL LEAD TO LOWER TEMPS IN
THE NORTHWEST PARTS OF THE CWA BY TUESDAY MORNING...THOUGH MUGGY
VALUES WILL REMAIN TO THE SOUTH AND EAST. DRIER AIR TAKES OVER ON
TUESDAY BRINGING A NICE CHANGE...MAKING FOR A PLEASANTLY DRY AND
COOLER DAY.
AGAIN USED THE CONSSHORT AND ITS BC VERSION FOR A STARTING POINT WITH
THE DEWPOINT AND WIND GRIDS...RESPECTIVELY...UNTIL 00Z TUESDAY...
FOLLOWED THE CONSALL FOR THE REST. FOR TEMPS...ADJUSTED THE CONSALL
FOR SOME MINOR TERRAIN ENHANCEMENTS IN THE LOWS TONIGHT WITH THE
HOURLY DIURNAL CURVE DERIVED FROM THE NAM12. AS FOR POPS...ENDED UP
CLOSER TO THE WETTER MAV GUIDANCE TODAY...AND SIMILAR TO BOTH
TONIGHT...THEN DRY ON TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 2 2013
NOT A LOT OF CHANGE FOR THE EXTENDED PERIOD. TUESDAY NIGHT/WEDNESDAY
SHOULD BEGIN WITH UPPER LEVEL TROUGHING AND SURFACE HIGH PRESSURE IN
PLACE WITH LIGHT WINDS. THE ONLY MOISTURE AVAILABLE IN THE
ATMOSPHERE WILL BE IN THE UPPER LEVELS WEDNESDAY AFTERNOON...WITH
ABUNDANT DRYING BELOW. AS A RESULT...SOME CIRRUS CLOUDS WILL BE
PRESENT...BUT OTHERWISE WEATHER WILL BE QUITE BENIGN. COOLER AND
DRIER AIR FLOWING IN FROM CANADA WILL KEEP HIGH TEMPS AND HUMIDITY
AT BAY.
FOR THURSDAY...MUCH OF THE SAME IS EXPECTED THROUGH THE FIRST HALF
OF THE DAY. THEN...AS WAS MENTIONED IN PREVIOUS FORECAST...AN
IMPULSE DROPPING INTO A LARGE UPPER TROUGH OVER THE NE CONUS AND SE
CANADA WILL SEND ANOTHER COLD FRONT SOUTH TOWARD THE LOCAL AREA
THURSDAY AFTERNOON OR THURSDAY NIGHT. HOWEVER... VIRTUALLY NO LOW
LEVEL MOISTURE RETURN IS EXPECTED...AND THE FRONT SHOULD BE DYING
OUT AS IT APPROACHES...WITH ALMOST NO IMPACT ON OUR LOCAL
WEATHER. AS THE FRONT DIES...HIGH PRESSURE DROPPING IN BEHIND IT
WILL MERGE WITH HIGH PRESSURE ORIGINALLY TO THE SOUTH OF THE
FRONT...WITH THE LOCAL RESULT BEING DRY WEATHER UNDER ITS DOMINANCE
THROUGH AT LEAST FRIDAY NIGHT.
A WEAK DISTURBANCE WILL TRY TO MOVE THROUGH THE OHIO VALLEY AND ERN
KY LATE IN THE WEEKEND. HOWEVER AT THIS POINT...LATEST GFS SOUNDINGS
ARE STILL LOOKING RATHER LACKLUSTER FOR ANY WIDESPREAD PRECIP
CHANCES. THE GFS IS STILL TRYING TO PINPOINT SOME AFTERNOON
CONVECTION OVER THE HIGHER APPALACHIAN TERRAIN THROUGH THE
WEEKEND...REACHING INTO THE FAR SE COALFIELDS OF KY. THE ECMWF HAS
THE SAME IDEA...BUT CONTINUES TO KEEP ALL PRECIP CHANCES TO OUR SE
OVER THE HIGHER APPALACHIAN TERRAIN. ALL THINGS CONSIDERED...WITH
LITTLE AGREEMENT OR SYNOPTIC SUPPORT...WILL CONTINUE WITH ONLY
SLIGHT CHANCE POPS AT BEST FOR THE FAR SE COUNTIES DURING THE
WEEKEND. ELSEWHERE...THE RETURN OF MORE SRLY FLOW WILL ALLOW
TEMPERATURES TO INCREASE SLIGHTLY THROUGHOUT THE WEEKEND...REACHING
THE MID AND UPPER 80S. HUMIDITY VALUES ON THE OTHER HAND WILL REMAIN
AT BAY...KEEPING CONDITIONS WARM BUT PLEASANT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 740 AM EDT MON SEP 2 2013
THE LOWER CIGS HAVE NOW MOVED OFF TO THE EAST SO VFR CONDITIONS
SHOULD PREVAIL FOR THE BULK OF THE PERIOD. THERE REMAINS TOO MUCH
UNCERTAINTY WITH TIMING AND COVERAGE OF ANY FRESH CONVECTION LATER
TODAY TO GO ANY MORE SPECIFIC THAN JUST A VCTS AT THE TAF SITES
THROUGH THE DAY. ACCOMPANYING THE STORMS COULD BE MVFR CIGS AND VIS.
THE STORM THREAT SHOULD END FROM NORTHWEST TO SOUTHEAST ACROSS THE
AREA BETWEEN 00 AND 02Z. SOME MVFR FOG COULD DEVELOP AROUND 08Z
TONIGHT AT LOZ...BUT THE OTHER SITES WILL LIKELY REMAIN CLEAR.
OUTSIDE OF ANY STORMS...WINDS WILL BE LIGHT AND VARIABLE...THOUGH
FAVORING THE WEST DURING THE AFTERNOON AND EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
345 AM CDT Mon Sep 2 2013
.SHORT TERM...(Today through Wednesday)
ISSUED AT 345 AM CDT MON SEP 2 2013
Cold front early this a.m. was approaching the NW part of our CWFA.
Near calm and saturated surface conditions allowing for areas of
fog especially SRN IL / SEMO where temps crossed over and are in the
upper 60s. Nothing on radar to speak of. Will keep conditions
convection free through the early morning hours. By 15-16z, the
NAM and HRRR drop the front to about the Ohio River with
instability developing ahead of it. Cannot rule out isolated
convection along and ahead of the front mainly over WKY late
morning through the afternoon, given the weak convergence, slight
steepening of mid level lapse rates and modest surface based
instability. Should anything get going, that chance will shift
south and east through late afternoon, followed by a gradual
lowering of humidity from the NW in the wake of the front.
Quiet, cooler weather tonight through Wednesday as high pressure
takes control and builds southward. For temps we used a blend of
MOS and bias corrected model input.
.LONG TERM...(Wednesday night through Monday)
ISSUED AT 345 AM CDT MON SEP 2 2013
At this time, the extended forecast period is a dry forecast. A
westward tilted ridge of high pressure with height persists over the
WFO PAH forecast area, with scant low level moisture available. The
only "ripple" in the forecast late next Sunday into Sunday night,
when there is a slightly troughiness that develops along the east
side of the mid-upper level ridge. However, given that this is such
a low PoP event in the first place, confidence is pretty low for any
measurable precipitation.
With northwest flow aloft east of the upper ridge and little in the
way of any significant changes in thickness values, kept
temperatures in the middle 80s to around 90 for nearly all of the
forecast period.
&&
.AVIATION...
ISSUED AT 345 AM CDT MON SEP 2 2013
Fog will remain a concern through daybreak with little wind. Best
chance of convection later today will generally be across west KY.
Chances appear too low to include in the TAF forecasts. We will see
winds come around to the NW in the wake of the front aob 10 kts.
Light north winds tonight with few clouds.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
350 AM EDT MON SEP 2 2013
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON SEP 2 2013
07Z SFC ANALYSIS SHOWS LOW PRESSURE MOVING THROUGH THE OHIO VALLEY
WITH A COLD FRONT PRESSING INTO KENTUCKY FROM THE NORTHWEST. ON THE
OTHER SIDE OF THAT BOUNDARY COOLER AND MUCH DRIER AIR IS FOUND. EAST
KENTUCKY IS ON THE OPPOSITE SIDE GIVING US ANOTHER MUGGY AND MILD
NIGHT WITH TEMPS AND DEWPOINTS WITHIN A FEW DEGREES OF 70. PLENTY OF
LOW LEVEL MOISTURE IS KEEPING SOME LOW LEVEL CLOUDS AROUND IN
ADDITION TO SUPPORTING THE DEVELOPMENT OF PATCHY VALLEY FOG...BUT THE
CONVECTION HAS REMAINED AT BAY.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM. THEY
ALL TAKE A DECENT...FOR LATE SUMMER...TROUGH THROUGH THE GREAT LAKES
AND OHIO VALLEY FROM TODAY INTO TUESDAY. THIS WILL SUPPORT LOW
HEIGHTS AND SHORT WAVE ENERGY PASSING THROUGH THE REGION TODAY AND
TONIGHT. THE TROUGH AXIS DOES GO THROUGH EAST KENTUCKY BY TUESDAY
MORNING...THOUGH...AND THIS WILL BE FOLLOWED BY RISING HEIGHTS IN
THE WAKE OF THE TROUGH. THE MESOSCALE WILL STILL DOMINATE OUR WEATHER
WITH DIFFERENTIAL HEATING AND OUTFLOW BOUNDARIES HELPING TO DRIVE THE
CONVECTION AHEAD OF THE COLD FRONT THAT WILL PUSH THROUGH EAST
KENTUCKY LATER TONIGHT. ACCORDINGLY...HAVE LEANED TOWARD THE HIGHER
RESOLUTION NAM12 FOR WEATHER DETAILS...BUT MORE BROAD BRUSHED WITH
THE SPECIFICS...ALONG WITH USING THE HRRR FOR THE NEAR TERM.
SENSIBLE WEATHER WILL FEATURE A RECHARGING OF THE AIR MASS OVER EAST
KENTUCKY TODAY WITH BUILDING INSTABILITY AHEAD OF THAT FRONT. THIS
SHOULD YIELD SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE AREA BY
MID AFTERNOON. GRADUALLY THE CONVECTION WILL SHRINK SOUTHEAST DURING
THE EVENING HOURS AS THE FRONT PUSHES THE DEEPER MOISTURE OUT OF THE
AREA. AS A RESULT...HAVE MAXED OUT POPS NEAR 00Z FOR THE AREA WITH A
TAPERING FROM NORTHWEST TO SOUTHEAST THEREAFTER. COOLER AIR FILTERING
INTO THE STATE IN THE WAKE OF THE FRONT WILL LEAD TO LOWER TEMPS IN
THE NORTHWEST PARTS OF THE CWA BY TUESDAY MORNING...THOUGH MUGGY
VALUES WILL REMAIN TO THE SOUTH AND EAST. DRIER AIR TAKES OVER ON
TUESDAY BRINGING A NICE CHANGE...MAKING FOR A PLEASANTLY DRY AND
COOLER DAY.
AGAIN USED THE CONSSHORT AND ITS BC VERSION FOR A STARTING POINT WITH
THE DEWPOINT AND WIND GRIDS...RESPECTIVELY...UNTIL 00Z TUESDAY...
FOLLOWED THE CONSALL FOR THE REST. FOR TEMPS...ADJUSTED THE CONSALL
FOR SOME MINOR TERRAIN ENHANCEMENTS IN THE LOWS TONIGHT WITH THE
HOURLY DIURNAL CURVE DERIVED FROM THE NAM12. AS FOR POPS...ENDED UP
CLOSER TO THE WETTER MAV GUIDANCE TODAY...AND SIMILAR TO BOTH
TONIGHT...THEN DRY ON TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 AM EDT MON SEP 2 2013
NOT A LOT OF CHANGE FOR THE EXTENDED PERIOD. TUESDAY NIGHT/WEDNESDAY
SHOULD BEGIN WITH UPPER LEVEL TROUGHING AND SURFACE HIGH PRESSURE IN
PLACE WITH LIGHT WINDS. THE ONLY MOISTURE AVAILABLE IN THE
ATMOSPHERE WILL BE IN THE UPPER LEVELS WEDNESDAY AFTERNOON...WITH
ABUNDANT DRYING BELOW. AS A RESULT...SOME CIRRUS CLOUDS WILL BE
PRESENT...BUT OTHERWISE WEATHER WILL BE QUITE BENIGN. COOLER AND
DRIER AIR FLOWING IN FROM CANADA WILL KEEP HIGH TEMPS AND HUMIDITY
AT BAY.
FOR THURSDAY...MUCH OF THE SAME IS EXPECTED THROUGH THE FIRST HALF
OF THE DAY. THEN...AS WAS MENTIONED IN PREVIOUS FORECAST...AN
IMPULSE DROPPING INTO A LARGE UPPER TROUGH OVER THE NE CONUS AND SE
CANADA WILL SEND ANOTHER COLD FRONT SOUTH TOWARD THE LOCAL AREA
THURSDAY AFTERNOON OR THURSDAY NIGHT. HOWEVER... VIRTUALLY NO LOW
LEVEL MOISTURE RETURN IS EXPECTED...AND THE FRONT SHOULD BE DYING
OUT AS IT APPROACHES...WITH ALMOST NO IMPACT ON OUR LOCAL
WEATHER. AS THE FRONT DIES...HIGH PRESSURE DROPPING IN BEHIND IT
WILL MERGE WITH HIGH PRESSURE ORIGINALLY TO THE SOUTH OF THE
FRONT...WITH THE LOCAL RESULT BEING DRY WEATHER UNDER ITS DOMINANCE
THROUGH AT LEAST FRIDAY NIGHT.
A WEAK DISTURBANCE WILL TRY TO MOVE THROUGH THE OHIO VALLEY AND ERN
KY LATE IN THE WEEKEND. HOWEVER AT THIS POINT...LATEST GFS SOUNDINGS
ARE STILL LOOKING RATHER LACKLUSTER FOR ANY WIDESPREAD PRECIP
CHANCES. THE GFS IS STILL TRYING TO PINPOINT SOME AFTERNOON
CONVECTION OVER THE HIGHER APPALACHIAN TERRAIN THROUGH THE
WEEKEND...REACHING INTO THE FAR SE COALFIELDS OF KY. THE ECMWF HAS
THE SAME IDEA...BUT CONTINUES TO KEEP ALL PRECIP CHANCES TO OUR SE
OVER THE HIGHER APPALACHIAN TERRAIN. ALL THINGS CONSIDERED...WITH
LITTLE AGREEMENT OR SYNOPTIC SUPPORT...WILL CONTINUE WITH ONLY
SLIGHT CHANCE POPS AT BEST FOR THE FAR SE COUNTIES DURING THE
WEEKEND. ELSEWHERE...THE RETURN OF MORE SRLY FLOW WILL ALLOW
TEMPERATURES TO INCREASE SLIGHTLY THROUGHOUT THE WEEKEND...REACHING
THE MID AND UPPER 80S. HUMIDITY VALUES ON THE OTHER HAND WILL REMAIN
AT BAY...KEEPING CONDITIONS WARM BUT PLEASANT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 230 AM EDT MON SEP 2 2013
THE MAIN CONCERN THROUGH THE REST OF THE NIGHT WILL BE A POTENTIAL
FOR FOG SINCE IT NOW APPEARS THAT ANY NEW CONVECTION WILL HOLD OFF
UNTIL AFTER DAY BREAK. WITH VARIABLE MID AND LOW LEVEL CLOUDS ABOUT
THE FOG MAY BE INTERMITTENT AND REMAIN PRINCIPALLY MVFR...WHERE IT
OCCURS. THE LOWER END OF THE CIGS WILL ALSO BE OCCASIONALLY MVFR.
HAVE ADDED THIS TO THE TAFS WITH A TEMPO DOWN TO IFR VIS DURING THE
PRE-DAWN HOURS INCLUDED AT LOZ. THERE IS STILL TOO MUCH UNCERTAINTY
WITH TIMING AND COVERAGE OF ANY FRESH CONVECTION ON MONDAY TO GO ANY
MORE SPECIFIC THAN JUST A VCTS AT THE TAF SITES THROUGH THE DAY...FOR
NOW. AGAIN...OUTSIDE OF ANY STORMS...WINDS WILL BE LIGHT AND
VARIABLE...THOUGH FAVORING THE WEST DURING THE AFTERNOON AND EVENING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 PM EDT MON SEP 2 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM EDT MON SEP 2 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE UPR GRT LKS TO THE W OF DEPARTING VIGOROUS SHRTWV
MOVING INTO QUEBEC AND E OF SLOWLY PROGRESSIVE UPR RDG IN THE
PLAINS. WITH LINGERING LLVL MSTR SHOWN ON THE 12Z INL/ GRB/APX
RAOBS...PLENTY OF LO CLDS LINGER OVER MUCH OF THE UPR LKS IN THE
LINGERING LLVL CYC NNW FLOW BTWN HI PRES CENTERED NEAR THE RED RIVER
VALLEY AND SFC LO IN QUEBEC. STRONG DNVA/SUBSIDENCE IN THE WAKE OF
THE DEPARTING DISTURBANCE HAS CAUSED THE SUBSIDENCE INVRN AT INL AND
APX TO SHARPEN AND FALL TO NEAR H875 AT 12Z. AT YPL...THE 12Z ROAB
SHOWS THE SUBSIDENCE INVRN HAS REACHED NEAR THE SFC. IN CONCERT WITH
LLVL DRYING...THE LO CLDS HAVE DSPTD ALONG AN AXIS FM NW ONTARIO
INTO WRN/NCENTRAL LK SUP AND THE KEWEENAW. THE SUBSIDENCE/LLVL
DRYING HAS ALSO TENDED TO DIMINISH THE -DZ/SPRINKLES THAT WERE
OCCURRING EARLIER.
MAIN FCST CONCERNS IN THE SHORT TERM ARE LO CLD TRENDS AND IMPACT ON
TEMPS TNGT.
TNGT...AS HI PRES BLDS SLOWLY EWD IN THE CONFLUENT NW FLOW ALF UNDER
RISING HGTS...EXPECT LINGERING LO CLDS OVER THE W AND CENTRAL TO
DIMINISH FAIRLY QUICKLY AS THE LLVL FLOW BACKS/BECOMES MORE ACYC AND
DRIER SFC-H925 AIR OVERSPREADS THE AREA. THE LO CLDS ARE LIKELY TO
BE MORE RESILIENT E OF MQT-ESC WITH A MORE NEUTRAL FLOW AND LESS
DRYING IN THE SFC-H925 LYR EXACERBATED BY LONGER FETCH OVER LK SUP
IN PERSISTENT NNW FLOW. THE LOWEST MIN TEMPS SHOULD OCCUR OVER THE
INTERIOR W...WHERE WINDS WL BE LIGHTER AND SKIES MOCLR AS PWAT IS
FCST TO FALL UNDER 0.5 INCH TOWARD 50-60 PCT OF NORMAL. UPSTREAM
TEMPS THIS MRNG FELL AS LO AS 40...SO GOING FCST TEMPS BOTTOMING OUT
IN THE UPR 30S AT THE COLD SPOTS OVER THE INTERIOR W LOOK ON TRACK.
PERSISTENT CLDS/ONSHORE FLOW WL CAUSE TEMPS TO RUN MUCH WARMER OVER
THE E. STEADY N WIND WL MAINTAIN HIER WAVES/HI SWIM RISK OVER THE
ALGER/MQT COUNTY BEACHES...BUT TEMPS WL BE CHILLY AND UNDER 60
DEGREES.
TUE...AS HI PRES BLDS TOWARD THE OH VALLEY...THE LLVL FLOW WL BACK
TO THE W. THIS WSHFT...LLVL DRYING AND DESCENDING SUBSIDENCE INVRN
WL BREAK UP ANY LINGERING LO CLDS OVER THE E IN THE MRNG. WITH
PLENTY OF AFTN SUNSHINE AND H85 TEMPS FCST TO WARM TO BTWN 16C OVER
THE W AND 12Z OVER THE E BY 00Z WED...EXPECT A MUCH WARMER AFTN.
MIXING TO H85 ON FCST SDNGS YIELDS HI TEMPS 75-80 OVER THE W HALF
AWAY FM LK MODERATION.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 427 PM EDT MON SEP 2 2013
NW FLOW WILL REMAIN STUCK ACROSS THE UPPER GREAT LAKES THROUGH AT
LEAST SUNDAY. AS IS TYPICAL WITH THE FAST PACED NW FLOW...TIMING OF
SMALLER DISTURBANCES WILL BE KEY IN OUR UPCOMING WEATHER...WHICH CAN
BE MORE DIFFICULT TO PREDICT.
AT 00Z WEDNESDAY OUR FIRST DISTURBANCE WILL BE SET UP ACROSS S
MANITOBA /COLD FRONT/. THE SFC-500MB LOW WILL BE SITUATED ACROSS
HUDSON BAY AND W QUEBEC...WITH THE TAIL END OF THE COLD FRONT
CROSSING LAKE SUPERIOR IN THE EVENING...BEFORE PUSHING ACROSS UPPER
MI OVERNIGHT.
OUR TUESDAY WARM-UP TO NEAR NORMAL AND SLIGHTLY ABOVE NORMAL
TEMPERATURES WILL BE SHORT LIVED...AS WE RETURN TO THE 60S FOR HIGHS
ON WEDNESDAY. 850MB TEMPS WILL FALL TO 7-10C WEDNESDAY...WHICH WILL
BE QUITE A DIFFERENCE FROM JUST 24 HOURS EARLIER WHERE THEY WERE
12-16C.
WITH CONTINUED N-NW FLOW OFF LAKE SUPERIOR 850MB TEMPS WILL CONTINUE
TO FALL TO 4-9C BY DAYBREAK THURSDAY...WITH -2C JUST NE OF LAKE
SUPERIOR. UNDER A MOSTLY CLEAR SKY...TEMPS IN THE LOW TO MID 40S MAY
NEED TO BE ADJUSTED LOWER. HUMIDITY VALUES WILL LIKELY FALL INTO THE
LOW TO MID 30S THURSDAY...ON 40S DEW POINTS AND LIGHT NW WINDS LESS
THAN 10KTS AS THE SFC HIGH SITS OVER THE UPPER GREAT LAKES. TEMPS
SHOULD JUMP BACK TO NEAR NORMAL VALUES ONCE AGAIN /70S/.
THE SFC HIGH WILL SINK TO THE OHIO VALLEY THURSDAY NIGHT...WITH
INCREASED WAA ON W WINDS..WITH TEMPS ON FRIDAY NEARING THE 80 DEGREE
MARK ACROSS THE ENTIRE CWA. THE CHANCE FOR WET WEATHER WILL RETURN
FRIDAY NIGHT THROUGH SATURDAY AS ANOTHER COLD FRONT SINKS ACROSS
FROM THE NW...FOLLOWED BY ANOTHER STRONGER SFC HIGH FOR SATURDAY
NIGHT THROUGH SUNDAY.
THERE WILL BE A CHANGE IN THE WORKS TO OUR FAR W AND E 500MB LOWS
STARTING MID WEEK...AS THE ENTIRE 500MB PATTERN BEGINS TO SLOWLY
SHIFT E. THIS WILL ALLOW THE RIDGE CENTERED OVER THE PLAINS STATE TO
BE PUSHED E ACROSS THE UPPER GREAT LAKES SUNDAY THROUGH MONDAY...IN
ADVANCE OF THE PACIFIC NW LOW MOVING TO THE CANADA/ND BORDER.
ONLY HAVE SLIGHT CHANCE THUNDER GOING FOR AND HIGH CHANCE POPS FOR
MONDAY...GIVEN THAT THE SYSTEM WILL LIKELY STILL BE SET UP ACROSS
THE DAKOTAS...AND TIMING IS A CONCERN INITIALLY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 123 PM EDT MON SEP 2 2013
AS DRY AIR PUSHES IN FM THE NNW AHEAD OF HI PRES MOVING E FM THE RED
RIVER VALLEY...EXPECT MVFR CIGS TO IMPROVE TO VFR N TO S AND AT SAW
BY 00Z. THE APRCH OF THE HI/WEAKER PRES GRADIENT WL ALSO RESULT IN
DIMINISHING/BACKING WINDS BY THIS EVNG. THEN VFR CONDITIONS WL
PREVAIL THRU 18Z TUE AS THE HI/DRIER AIRMASS DOMINATE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EDT MON SEP 2 2013
NNW WINDS UP TO 30 KTS WITH A FEW LINGERING GALE FORCE GUSTS OVER
THE E LATE THIS AFTERNOON WILL DIMINISH TONIGHT WITH THE APPROACH OF
HI PRES FROM THE W. EXPECT A WSW WIND UP TO 20-25 KTS ON TUE...
STRONGEST OVER THE NCENTRAL WHERE THIS FLOW IS ACCENTUATED BETWEEN
THE KEWEENAW AND ISLE ROYALE...TO SHIFT TO THE NNW ON TUE NIGHT
BEHIND A COLD FRONTAL PASSAGE AND LINGER THRU THE DAY ON WED. THE
MOST PERSISTENT AND STRONGER WINDS DURING THIS EVENT WILL OCCUR OVER
THE E UNDER A SHARPER PRES GRADIENT. THEN PLAN ON WINDS UNDER 25 KTS
ON THU THRU SAT AS A RELATIVELY WEAK PRES GRADIENT AND HI OVERWATER
STABILITY DOMINATE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ005-006.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
319 PM EDT MON SEP 2 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM EDT MON SEP 2 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CONFLUENT NW FLOW
ALF OVER THE UPR GRT LKS TO THE W OF DEPARTING VIGOROUS SHRTWV
MOVING INTO QUEBEC AND E OF SLOWLY PROGRESSIVE UPR RDG IN THE
PLAINS. WITH LINGERING LLVL MSTR SHOWN ON THE 12Z INL/ GRB/APX
RAOBS...PLENTY OF LO CLDS LINGER OVER MUCH OF THE UPR LKS IN THE
LINGERING LLVL CYC NNW FLOW BTWN HI PRES CENTERED NEAR THE RED RIVER
VALLEY AND SFC LO IN QUEBEC. STRONG DNVA/SUBSIDENCE IN THE WAKE OF
THE DEPARTING DISTURBANCE HAS CAUSED THE SUBSIDENCE INVRN AT INL AND
APX TO SHARPEN AND FALL TO NEAR H875 AT 12Z. AT YPL...THE 12Z ROAB
SHOWS THE SUBSIDENCE INVRN HAS REACHED NEAR THE SFC. IN CONCERT WITH
LLVL DRYING...THE LO CLDS HAVE DSPTD ALONG AN AXIS FM NW ONTARIO
INTO WRN/NCENTRAL LK SUP AND THE KEWEENAW. THE SUBSIDENCE/LLVL
DRYING HAS ALSO TENDED TO DIMINISH THE -DZ/SPRINKLES THAT WERE
OCCURRING EARLIER.
MAIN FCST CONCERNS IN THE SHORT TERM ARE LO CLD TRENDS AND IMPACT ON
TEMPS TNGT.
TNGT...AS HI PRES BLDS SLOWLY EWD IN THE CONFLUENT NW FLOW ALF UNDER
RISING HGTS...EXPECT LINGERING LO CLDS OVER THE W AND CENTRAL TO
DIMINISH FAIRLY QUICKLY AS THE LLVL FLOW BACKS/BECOMES MORE ACYC AND
DRIER SFC-H925 AIR OVERSPREADS THE AREA. THE LO CLDS ARE LIKELY TO
BE MORE RESILIENT E OF MQT-ESC WITH A MORE NEUTRAL FLOW AND LESS
DRYING IN THE SFC-H925 LYR EXACERBATED BY LONGER FETCH OVER LK SUP
IN PERSISTENT NNW FLOW. THE LOWEST MIN TEMPS SHOULD OCCUR OVER THE
INTERIOR W...WHERE WINDS WL BE LIGHTER AND SKIES MOCLR AS PWAT IS
FCST TO FALL UNDER 0.5 INCH TOWARD 50-60 PCT OF NORMAL. UPSTREAM
TEMPS THIS MRNG FELL AS LO AS 40...SO GOING FCST TEMPS BOTTOMING OUT
IN THE UPR 30S AT THE COLD SPOTS OVER THE INTERIOR W LOOK ON TRACK.
PERSISTENT CLDS/ONSHORE FLOW WL CAUSE TEMPS TO RUN MUCH WARMER OVER
THE E. STEADY N WIND WL MAINTAIN HIER WAVES/HI SWIM RISK OVER THE
ALGER/MQT COUNTY BEACHES...BUT TEMPS WL BE CHILLY AND UNDER 60
DEGREES.
TUE...AS HI PRES BLDS TOWARD THE OH VALLEY...THE LLVL FLOW WL BACK
TO THE W. THIS WSHFT...LLVL DRYING AND DESCENDING SUBSIDENCE INVRN
WL BREAK UP ANY LINGERING LO CLDS OVER THE E IN THE MRNG. WITH
PLENTY OF AFTN SUNSHINE AND H85 TEMPS FCST TO WARM TO BTWN 16C OVER
THE W AND 12Z OVER THE E BY 00Z WED...EXPECT A MUCH WARMER AFTN.
MIXING TO H85 ON FCST SDNGS YIELDS HI TEMPS 75-80 OVER THE W HALF
AWAY FM LK MODERATION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON SEP 2 2013
TROUGH OVER QUEBEC TO START ON TUESDAY EXPECTED TO LIFT SLOWLY TO
THE NORTH THROUGH THE WEEK. TROUGH WILL EVENTUALLY BE SWEPT UP BY
STRONGER TROUGH AND VIGOROUS SFC LOW DROPPING ACROSS HUDSON BAY INTO
NORTHERN QUEBEC BY WEDNESDAY. DEEP TROUGH THEN MEANDERS ACROSS
NORTHEAST CANADA BY THE END OF THE WEEK. UPSTREAM OF THAT FEATURE
OVER THE GREAT LAKES...NW FLOW ALOFT REMAINS IN PLACE ON EDGE OF
STRONGER RIDGE CENTERED OVR THE ROCKIES. DISTURBANCES SLIDING ACROSS
UPPER GREAT LAKES IN THIS PATTERN APPEAR MINIMAL.
FIRST SFC COLD FRONT TO IMPACT THE LONG TERM DROPS ACROSS UPPER
LAKES WEDNESDAY MORNING BEFORE HIGH PRESSURE BUILDS BACK IN FOR
THURSDAY. MODEL CONSENSUS FAVORS FROPA AROUND 09Z OVR FAR NORTH CWA
SHIFTING OUT OF SOUTHERN CWA BTWN 15Z-18Z. GFS WAS SHOWING SLOWER
FROPA IN EARLIER RUNS...BUT HAS NOW TRENDED QUICKER AND IS IN LINE
WITH THE CONSENSUS. STRONG SHORTWAVE DIGGING ACROSS NORTHERN ONTARIO
EARLY WEDNESDAY MORNING WITH BULK OF DEEP LAYER Q-VECTOR CONVERGENCE
STAYING WELL TO NORTH. HOWEVER...AREA OF WEAKER H7-H3 Q-VECTOR
CONVERGENCE AND ENHANCED H8-H7 RH COULD CLIP EASTERN CWA BTWN 09Z-
15Z. 5KM NAM DNG ONLY MODEL THAT GENERATES LGT QPF THERE. SOME OTHER
MODELS DO KICK OFF SOME DZ OVR UPSLOPE AREAS OF NCNTRL UPR MICHIGAN
THOUGH. LOW-LEVEL MOISTURE LOOKS VERY TRANSIENT THOUGH AND SUBSIDENCE
BEHIND THIS BRIEF UPTICK OF MOISTURE IS STRONG. WILL KEEP FCST
DRY...BUT IF THESE SIGNALS PERSIST MAY NEED TO ADD A BRIEF PERIOD OF
SOME LGT PRECIP EARLY ON WEDNESDAY. IN WAKE OF THE FRONT...NORTH
WINDS AND THERMAL TROUGHING AT H9 SHOULD KEEP TEMPS ON THE COOLER
SIDE...ESPECIALLY OVER THE NORTH CWA DUE TO GUSTY NORTH-NORTHWEST
WINDS OFF LK SUPERIOR. BASED ON MIXING TO H9-H875 WOULD EXPECT HIGHS
IN THE LOW TO MID 60S NORTH AND MAYBE INTO THE LOWER 70S SOUTH. EVEN
IN THE SOUTH CWA...READINGS MAY HAVE HARD TIME REACHING 70 DEGREES IF
MODELS ARE CORRECT WITH STRENGTH OF THERMAL TROUGHING. GUSTY WINDS
AND COLD AIR ADVECTION WILL KICK UP WAVES ON LK SUPERIOR RESULTING IN
ANOTHER HIGHER SWIM RISK FOR WEDNESDAY.
KEPT THE COOLER THEME GOING INTO WEDNESDAY NIGHT AS WELL AS WINDS
BECOME LIGHT AND AIRMASS ACROSS AREA IS DRY WITH PWATS LESS THAN
0.50 INCHES. MAY SEE THIN MID CLOUDS...BUT DO NOT EXPECT THESE TO
IMPACT TEMPS TOO MUCH. TRENDED MIN TEMPS TOWARD THE BIAS CORRECTED
NAM/GFS/ECMWF WHICH RESULTED IN READINGS AS LOW AS 40 DEGREES IN
FAVORED COLD SPOTS. MAY EVEN BE A BIT COOLER...BUT NOT QUITE BUYING
THE MID 30S IN PARTS OF THE CNTRL AND EASTERN CWA THAT SOME GUIDANCE
SHOWED...NOT QUITE YET ANYWAY.
GENERALLY AHEAD OF ANOTHER COLD FRONT THURSDAY INTO FRIDAY...THEN
ANOTHER FRONT DROPS ACROSS UPPER LAKES FRIDAY OR FRIDAY NIGHT.
AIRMASS NOT ALL THAT COLD AHEAD OF THIS FRONT...SO TEMPS ON THU
SHOULD END UP AT OR A BIT ABOVE NORMAL. TEMPS ON FRIDAY MAY END
UP WELL ABOVE NORMAL AS LOW-LEVEL WINDS ARE FM WSW AND H85 TEMPS ARE
OVER +16C. COULD SEE WIDESPREAD 80S IF CLOUDS/PRECIP DO NOT MUDDLE
THINGS TOO MUCH. PREVIOUS ECMWF AND RECENT GEM-NH SHOWED COLD FRONT
COMING IN QUICKER ON FRIDAY AFTN WHILE LATEST ECMWF SHOWS FROPA MORE
FRIDAY NIGHT WITH THE GFS MORE ON SATURDAY. NOT TOO SURPRISING THIS
FAR OUT...BUT ECMWF HAS BEEN A BIT BACK AND FORTH ON TIMING OF
FRONT...SO CONFIDENCE IN DETAILS LOWER BY FRIDAY. A QUICKER FRONTAL
PASSAGE WOULD SUPPORT BETTER CHANCE OF SHRA/TSRA OVER PARTS OF CWA ON
FRIDAY AS INSTABILITY AND SHEAR /MLCAPES UP TO 1000J/KG AND 0-6KM
SHEAR UP TO 30 KTS/ LOOK SUFFICIENT ENOUGH GIVEN STRONG ENOUGH
CONVERGENCE FROM FRONT. GIVEN THE TIMING CONCERNS WITH FROPA...KEPT
THE SLIGHT CHANCE POPS THAT MODEL CONSENSUS YIELDS. DOES SEEM THAT
ONCE THE TIMING OF FRONT IS BETTER AGREED UPON...POPS COULD BE
INCREASED FOR A BRIEF TIME DURING THE EXPECTED FROPA.
HIGH PRESSURE THEN BUILDS ACROSS UPPER GREAT LAKES FOR NEXT WEEKEND.
FRONTAL BOUNDARY THAT MOVES THROUGH EARLY IN THE WEEKEND MAY REMAIN
ACTIVE JUST TO SOUTH AND WEST OF CWA WITH A LOT OF WARMTH AND
INSTABILITY POOLING OVER THE PLAINS AND FOLDING INTO THE FRONTAL
BOUNDARY. AS LONG AS SFC OR H85 BOUNDARIES STAY TO SOUTH AND WEST AS
ECMWF AND WPC HAND DRAWN PROGS INDICATE...SHOULD SEE DRY WEATHER MOST
OF NEXT WEEKEND WITH TEMPS AROUND NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 123 PM EDT MON SEP 2 2013
AS DRY AIR PUSHES IN FM THE NNW AHEAD OF HI PRES MOVING E FM THE RED
RIVER VALLEY...EXPECT MVFR CIGS TO IMPROVE TO VFR N TO S AND AT SAW
BY 00Z. THE APRCH OF THE HI/WEAKER PRES GRADIENT WL ALSO RESULT IN
DIMINISHING/BACKING WINDS BY THIS EVNG. THEN VFR CONDITIONS WL
PREVAIL THRU 18Z TUE AS THE HI/DRIER AIRMASS DOMINATE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 PM EDT MON SEP 2 2013
NNW WINDS UP TO 30 KTS WITH A FEW LINGERING GALE FORCE GUSTS OVER
THE E LATE THIS AFTERNOON WILL DIMINISH TONIGHT WITH THE APPROACH OF
HI PRES FROM THE W. EXPECT A WSW WIND UP TO 20-25 KTS ON TUE...
STRONGEST OVER THE NCENTRAL WHERE THIS FLOW IS ACCENTUATED BETWEEN
THE KEWEENAW AND ISLE ROYALE...TO SHIFT TO THE NNW ON TUE NIGHT
BEHIND A COLD FRONTAL PASSAGE AND LINGER THRU THE DAY ON WED. THE
MOST PERSISTENT AND STRONGER WINDS DURING THIS EVENT WILL OCCUR OVER
THE E UNDER A SHARPER PRES GRADIENT. THEN PLAN ON WINDS UNDER 25 KTS
ON THU THRU SAT AS A RELATIVELY WEAK PRES GRADIENT AND HI OVERWATER
STABILITY DOMINATE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ005-006.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
127 PM EDT MON SEP 2 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 324 AM EDT MON SEP 2 2013
A COLD FRONT IS MOVING THROUGH LOWER MICHIGAN EARLY THIS MORNING.
MUCH DRIER AND COOLER AIR WILL FLOW INTO THE REGION TODAY RESULTING
IN HIGHS IN THE LOWER TO MID 70S AND MUCH LOWER HUMIDITY.
TEMPERATURES WILL SLOWLY WARM TO THE LOWER 80S BY THE END OF THE
WEEKEND. DRY WEATHER IS EXPECTED THIS WEEK.
&&
.UPDATE...
ISSUED AT 1142 AM EDT MON SEP 2 2013
MODELS ARE FORECASTING A FAIR AMOUNT OF MOISTURE IN BOTH THE
925-850MB AND THE 950-900MB LAYERS. DEEP CYCLONIC FLOW WILL REMAIN
IN PLACE THROUGH THE COURSE OF THE AFTERNOON AS WELL WITH DELTA
T/S OVER LAKE MICHIGAN ON THE ORDER OF 14 DEGREES C. ALL OF THESE
FACTORS LEAD TOWARD A DECENT AMOUNT OF CLOUD COVER. EXPECT SKIES
TO STAY MAINLY CLOUDY IN THE NORTHERN PORTION OF THE FORECAST
AREA (U.S. 10)...BECOMING MOSTLY CLOUDY IN THE CENTRAL (I-96) AND
VARYING CONDITIONS IN THE SOUTH (I-94) BETWEEN PARTLY SUNNY AND
MOSTLY CLOUDY.
THE CLOUDS AND COLD AIR ADVECTION SHOULD KEEP HIGHS BELOW NORMALS
FOR THIS TIME OF YEAR. HIGHS WILL TOP OUT IN THE MID TO UPPER 60S
NORTH AND MID 70S IN THE FAR SOUTH. CANNOT RULE OUT A FEW
SPRINKLES OFF OF LAKE MICHIGAN THIS AFTERNOON AND EVENING BUT HAVE
NOT PUT THEM IN THE FORECAST AT THIS POINT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 324 AM EDT MON SEP 2 2013
FORECAST CONCERNS ARE MINIMAL THIS MORNING AS DRY WX IS EXPECTED
THROUGH THE PERIOD.
SFC ANALYSIS SHOWS A COLD FRONT HAS PUSHED THROUGH THE CWA. THE LAST
OF THE SHOWERS THAT DEVELOPED AHEAD OF THE FRONT HAVE ALSO MOVED
EAST OUT OF THE CWA. IR LOOP SHOWS CLEAR SKIES MOVING IN BEHIND THE
FRONT. THAT WILL BE SHORT LIVED THOUGH BECAUSE A LARGE AREA OF
STRATOCU OVER ONTARIO/NRN LWR IS MOVING SOUTH ON THE HEELS OF A
NORTH WIND. H9 RH PROGS SUGGEST THAT QUITE A BIT OF CLOUDINESS
WILL BE WITH US THROUGH TONIGHT COURTESY OF A STRONG SHORT WAVE
MOVING ACROSS NRN LAKE HURON. A LARGE DOME OF HIGH PRESSURE OVER
THE CENTRAL ROCKIES WILL RESULT IN NW FLOW OVER THE GREAT LAKES.
THIS IS USUALLY A DRY FLOW AND THAT/S WHAT WE/LL SEE THROUGH
WEDNESDAY. AFTER THE SHORT WAVE MOVES EAST LATE TONIGHT...CLEARING
WILL OCCUR.
HIGHS TODAY WILL RUN FROM THE MID 60S IN THE NORTH TO MID 70S IN THE
SOUTH. WE/LL SEE A GRADUAL WARMING TREND THROUGH WEDNESDAY AS SOME
WARMER AIR FROM THE PLAINS GETS PUSHED NEWD TOWARD THE GREAT LAKES
AHEAD OF THE NEXT FRONT MIDWEEK.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 324 AM EDT MON SEP 2 2013
NOT MUCH IN THE WAY OF WEATHER IN THE EXTENDED AS ONLY A SLIGHT
CHANCE OF RAIN EXPECTED WITH A COLD FRONT PASSAGE ON SATURDAY. THE
ECMWF IS NOW A BIT QUICKER THAN THE GFS WITH SHOWERS COMING IN
FRIDAY NIGHT. KEPT POPS LIMITED TO SATURDAY.
WEDNESDAY NIGHT OR THURSDAY COULD ALSO HAVE A FEW SHOWERS AS A COLD
FRONT COMES THROUGH...BUT IT IS WEAKENING AND MOISTURE IS LIMITED SO
DECIDED TO KEEP THOSE PERIODS DRY FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 130 PM EDT MON SEP 2 2013
AREAS OF LAKE ENHANCED MVFR BKN CLOUD CEILINGS THROUGH EVENING WITH VFR
SCT CLDS OVERNIGHT. BEST COVERAGE WILL BE NORTHWEST OF A KAZO TO
KLAN LINE. CLOUD BASES WILL RANGE FROM 025-035 KFT WITH TOPS
GENERALLY BELOW 080 KFT.
MAY SEE SOME VERY LOCALIZE FOG IN LOW LYING AREAS...RIVERS...ETC
TUE MORNING BUT AGAIN...VERY LOCALIZED.
OUTLOOK...VFR CLOUD CEILINGS 030-050 KFT POSSIBLE TUE MIDDAY THEN
CIG AND VIS UNLIMITED FROM TUE AFTN THROUGH WED.
&&
.MARINE...
ISSUED AT 1142 AM EDT MON SEP 2 2013
WINDS BENT MORE OFF SHORE THIS MORNING AND WHILE WAVES WERE UP
INITIALLY AT THE BEACHES THEY HAVE DROPPED SOME MID TO LATE
MORNING. THE HRRR FORECASTS THE WINDS TO COME BACK TO ABOUT 340
DEGREES OR FROM THE NORTH-NORTHWEST THIS AFTERNOON AND EVENING.
THEREFORE NO CHANGES WERE MADE TO THE SMALL CRAFT ADVISORY OR THE
BEACH HAZARDS STATEMENT. WHILE THE DIRECTION IS NOT IDEAL FOR HIGH
WAVES RIGHT AT THE SHORE IT SHOULD BE GOOD ENOUGH TO PRODUCE 3-5
FOOTERS AS WE HEAD THROUGH THE COURSE OF THE AFTERNOON AND
EVENING. STRUCTURAL CURRENTS AND LONGSHORE CURRENTS WILL BECOME
MORE OF A PLAYER TOO AS THE WINDS BACK. THE HIGHEST WAVES IN THIS
FLOW REGIME WILL BE NORTH OF WHITEHALL AND SOUTH OF HOLLAND. AS
EXPECTED...THE CLOUDS AND COOL TEMPERATURES HAVE KEPT BEACH
POPULATION DOWN WITH THE SURF CAM AT GRAND HAVEN SHOWING LIMITED
FOLKS ON THE BEACH. FOR THOSE ON THE BEACH HOWEVER CONDITIONS WILL
BECOME MORE HAZARDOUS AS WE HEAD THROUGH THE DAY...ESPECIALLY
BEACHES ON THE NORTH SIDES OF NORTH PIERS AND BREAKWALLS.
&&
.HYDROLOGY...
ISSUED AT 324 AM EDT MON SEP 2 2013
NO HYDRO CONCERNS. DRY WEATHER IS EXPECTED THIS WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...93
SHORT TERM...93
LONG TERM...OSTUNO
AVIATION...COBB
HYDROLOGY...93
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1143 AM EDT MON SEP 2 2013
LATEST UPDATE...
UPDATE/MARINE
.SYNOPSIS...
ISSUED AT 324 AM EDT MON SEP 2 2013
A COLD FRONT IS MOVING THROUGH LOWER MICHIGAN EARLY THIS MORNING.
MUCH DRIER AND COOLER AIR WILL FLOW INTO THE REGION TODAY RESULTING
IN HIGHS IN THE LOWER TO MID 70S AND MUCH LOWER HUMIDITY.
TEMPERATURES WILL SLOWLY WARM TO THE LOWER 80S BY THE END OF THE
WEEKEND. DRY WEATHER IS EXPECTED THIS WEEK.
&&
.UPDATE...
ISSUED AT 1142 AM EDT MON SEP 2 2013
MODELS ARE FORECASTING A FAIR AMOUNT OF MOISTURE IN BOTH THE
925-850MB AND THE 950-900MB LAYERS. DEEP CYCLONIC FLOW WILL REMAIN
IN PLACE THROUGH THE COURSE OF THE AFTERNOON AS WELL WITH DELTA
T/S OVER LAKE MICHIGAN ON THE ORDER OF 14 DEGREES C. ALL OF THESE
FACTORS LEAD TOWARD A DECENT AMOUNT OF CLOUD COVER. EXPECT SKIES
TO STAY MAINLY CLOUDY IN THE NORTHERN PORTION OF THE FORECAST
AREA (U.S. 10)...BECOMING MOSTLY CLOUDY IN THE CENTRAL (I-96) AND
VARYING CONDITIONS IN THE SOUTH (I-94) BETWEEN PARTLY SUNNY AND
MOSTLY CLOUDY.
THE CLOUDS AND COLD AIR ADVECTION SHOULD KEEP HIGHS BELOW NORMALS
FOR THIS TIME OF YEAR. HIGHS WILL TOP OUT IN THE MID TO UPPER 60S
NORTH AND MID 70S IN THE FAR SOUTH. CANNOT RULE OUT A FEW
SPRINKLES OFF OF LAKE MICHIGAN THIS AFTERNOON AND EVENING BUT HAVE
NOT PUT THEM IN THE FORECAST AT THIS POINT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 324 AM EDT MON SEP 2 2013
FORECAST CONCERNS ARE MINIMAL THIS MORNING AS DRY WX IS EXPECTED
THROUGH THE PERIOD.
SFC ANALYSIS SHOWS A COLD FRONT HAS PUSHED THROUGH THE CWA. THE LAST
OF THE SHOWERS THAT DEVELOPED AHEAD OF THE FRONT HAVE ALSO MOVED
EAST OUT OF THE CWA. IR LOOP SHOWS CLEAR SKIES MOVING IN BEHIND THE
FRONT. THAT WILL BE SHORT LIVED THOUGH BECAUSE A LARGE AREA OF
STRATOCU OVER ONTARIO/NRN LWR IS MOVING SOUTH ON THE HEELS OF A
NORTH WIND. H9 RH PROGS SUGGEST THAT QUITE A BIT OF CLOUDINESS
WILL BE WITH US THROUGH TONIGHT COURTESY OF A STRONG SHORT WAVE
MOVING ACROSS NRN LAKE HURON. A LARGE DOME OF HIGH PRESSURE OVER
THE CENTRAL ROCKIES WILL RESULT IN NW FLOW OVER THE GREAT LAKES.
THIS IS USUALLY A DRY FLOW AND THAT/S WHAT WE/LL SEE THROUGH
WEDNESDAY. AFTER THE SHORT WAVE MOVES EAST LATE TONIGHT...CLEARING
WILL OCCUR.
HIGHS TODAY WILL RUN FROM THE MID 60S IN THE NORTH TO MID 70S IN THE
SOUTH. WE/LL SEE A GRADUAL WARMING TREND THROUGH WEDNESDAY AS SOME
WARMER AIR FROM THE PLAINS GETS PUSHED NEWD TOWARD THE GREAT LAKES
AHEAD OF THE NEXT FRONT MIDWEEK.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 324 AM EDT MON SEP 2 2013
NOT MUCH IN THE WAY OF WEATHER IN THE EXTENDED AS ONLY A SLIGHT
CHANCE OF RAIN EXPECTED WITH A COLD FRONT PASSAGE ON SATURDAY. THE
ECMWF IS NOW A BIT QUICKER THAN THE GFS WITH SHOWERS COMING IN
FRIDAY NIGHT. KEPT POPS LIMITED TO SATURDAY.
WEDNESDAY NIGHT OR THURSDAY COULD ALSO HAVE A FEW SHOWERS AS A COLD
FRONT COMES THROUGH...BUT IT IS WEAKENING AND MOISTURE IS LIMITED SO
DECIDED TO KEEP THOSE PERIODS DRY FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 745 AM EDT MON SEP 2 2013
SOME MVFR AND IFR CEILINGS WILL BE GIVING WAY TO VFR CONDITIONS
THIS MORNING AS LOW STRATUS DECK DECREASES. NORTH WINDS WILL GUST
TO 15 TO 20 KNOTS AT TIMES.
&&
.MARINE...
ISSUED AT 1142 AM EDT MON SEP 2 2013
WINDS BENT MORE OFF SHORE THIS MORNING AND WHILE WAVES WERE UP
INITIALLY AT THE BEACHES THEY HAVE DROPPED SOME MID TO LATE
MORNING. THE HRRR FORECASTS THE WINDS TO COME BACK TO ABOUT 340
DEGREES OR FROM THE NORTH-NORTHWEST THIS AFTERNOON AND EVENING.
THEREFORE NO CHANGES WERE MADE TO THE SMALL CRAFT ADVISORY OR THE
BEACH HAZARDS STATEMENT. WHILE THE DIRECTION IS NOT IDEAL FOR HIGH
WAVES RIGHT AT THE SHORE IT SHOULD BE GOOD ENOUGH TO PRODUCE 3-5
FOOTERS AS WE HEAD THROUGH THE COURSE OF THE AFTERNOON AND
EVENING. STRUCTURAL CURRENTS AND LONGSHORE CURRENTS WILL BECOME
MORE OF A PLAYER TOO AS THE WINDS BACK. THE HIGHEST WAVES IN THIS
FLOW REGIME WILL BE NORTH OF WHITEHALL AND SOUTH OF HOLLAND. AS
EXPECTED...THE CLOUDS AND COOL TEMPERATURES HAVE KEPT BEACH
POPULATION DOWN WITH THE SURF CAM AT GRAND HAVEN SHOWING LIMITED
FOLKS ON THE BEACH. FOR THOSE ON THE BEACH HOWEVER CONDITIONS WILL
BECOME MORE HAZARDOUS AS WE HEAD THROUGH THE DAY...ESPECIALLY
BEACHES ON THE NORTH SIDES OF NORTH PIERS AND BREAKWALLS.
&&
.HYDROLOGY...
ISSUED AT 324 AM EDT MON SEP 2 2013
NO HYDRO CONCERNS. DRY WEATHER IS EXPECTED THIS WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MIZ037-
043-050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...93
SHORT TERM...93
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...93
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
130 AM EDT MON SEP 2 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 401 PM EDT SUN SEP 1 2013
12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PAIR OF VIGOROUS
SHRTWVS DIGGING THRU ONTARIO/LK SUP IN THE NW FLOW ALF BTWN RDG OVER
THE ROCKIES AND A TROF OVER ERN NAMERICA. WHILE DRYING ALF UNDER
DNVA/UPR CONFLUENCE/DEEP LYR QVECTOR DVGC IN THE WAKE OF THE MOST
IMPRESSIVE SHRTWV MOVING ACRS NRN LK SUP HAS ENDED THE SHRA OVER THE
SW CWA...MORE NMRS SHRA/TS IN THE COMMA TAIL IN ADVANCE OF RATHER
WEAK ATTENDANT COLD FNT...WHERE RUC ANALYSIS SHOWS KINX NOT FAR FM
40/STEEPER MID LVL LAPSE RATES/MUCAPE IN THE 500-1000J/KG RANGE...
ARE MOVING THRU THE ERN ZNS. MORE NMRS SHRA/TS ALSO IMPACTED THE
KEWEENAW EARLIER IN THE DAY CLOSER TO THE COMMA HEAD ASSOCIATED WITH
THIS SHRTWV. THE MAIN HAZARD FM ALL THE SHRA/TS HAVE BEEN HEAVY
DOWNPOURS...WHICH PROMPTED THE ISSUANCE OF AN URBAN/SMALL STREAM
FLOOD ADVY FOR THE KEWEENAW EARLIER IN THE AFTN FOLLOWING A REPORT
OF 2 INCHES OF RA IN AN HOUR NEAR CALUMET. EVEN THOUGH THERE HAS
BEEN DRYING ALF OVER THE W IN THE WAKE OF THE WEAK SFC COLD
FROPA...A FEW -SHRA HAVE DVLPD IN THIS AREA ALONG WITH SOME LO CLDS
AS LLVL MSTR SHOWN ON THE 12Z INL RAOB HAS OVERSPREAD THE AREA IN
THE NW LLVL FLOW IN THE WAKE OF THE SHRTWV. LARGE SCALE QVECTOR
DVGC/SUBSIDENCE IN THE WAKE OF THE DEPARTING SHRTWV HAVE TENDED TO
LIMIT THE INTENSITY OF THESE -SHRA. THERE IS A SHARPER SURGE OF COOL
AIR ASSOCIATED WITH THE SECOND SHRTWV DROPPING SSEWD IN NW ONTARIO.
LO CLDS ARE WIDESRPEAD TO THE NW OF LK SUP WITH SOME -RA/-DZ
REPORTED IN THE CYC FLOW ON THE NW FLANK OF SFC LO PRES MOVING THRU
LK SUP THAT ASSOCIATED WITH THE FIRST SHRTWV.
REST OF THIS AFTN/TNGT...EXPECT LINGERING SHRA/TS OVER THE ERN ZNS
LATE THIS AFTN TO SHIFT TO THE E FOLLOWING DEPARTURE OF AXIS OF HIER
RH/DEEP LYR QVECTOR CNVGC AND UNDER DEEP LYR QVECTOR DVGC BEHIND
DEPARTING FIRST SHRTWV. FOLLOWING THE PASSAGE OF REINFORCING COLD
FNT EARLY THIS EVNG ASSOCIATED WITH THE SECOND SHRTWV DIGGING THRU
ONTARIO...EXPECT WIDESPREAD LO CLD/SOME -DZ TO DVLP ESPECIALLY IN
THE UPSLOPE AREAS NEAR LK SUP AS LLVL NNW FLOW DRIVES NEAR SFC COOL
AIR INTO THE AREA AND SHARPENS INVRN BASE NEAR H9 AS SHOWN ON 12Z
LOCAL WRF ARW FCST SDNGS. THE COMBINATION OF GUSTY WINDS WITH H925
WINDS FCST UP TO 25-30 KTS AND THE ARRIVAL OF THE COOLER AIR WL MAKE
THE NGT FEEL QUITE CHILLY AS COMPARED TO THE WARM WX IN RECENT WEEKS.
LABOR DAY...MON WL FEATURE A CONFLUENT NW FLOW OVER THE UPR LKS/DEEP
LYR QVECTOR DVGC. MAIN FCST CONCERN IS HOW QUICKLY LO CLDS/-DZ WITH
SHALLOW MOIST LYR BLO SHARP LLVL INVRN WL DEPART. GIVEN THE
INTENSITY OF THE DISTURBANCES IN PLAY TODAY...PREFERRED TO FOLLOW
THE 12Z LOCAL WRF-ARW FCST SCENARIO...WHICH SHOWS MORE PERSISTENT
LLVL MSTR MAINTAINED BY STRONGER N WIND. BUT EVEN THIS MODEL
INDICATES SOME IMPROVEMENT IN THE AFTN ESPECIALLY OVER THE W HALF
WITH CLOSER APRCH OF SFC HI PRES/WEAKER AND MORE ACYC FLOW. EXPECT
THE RETURN OF AT LEAST SOME SUNSHINE IN THAT AREA AFT 18Z. TEMPS WL
RUN BLO NORMAL FOR THE FIRST TIME IN QUITE AWHILE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 401 PM EDT SUN SEP 1 2013
QUITE A TRANQUIL PERIOD OF WEATHER EXPECTED OVER THE NEXT WEEK AS
LARGE SCALE FEATURES TREND BACK TO THE EARLY SUMMER SET-UP OF A
WESTERN RIDGE AND EASTERN TROUGH. TEMPERATURES SHOULD BE AT TO
SLIGHTLY ABOVE NORMAL THROUGH THE WEEK.
MONDAY NIGHT THROUGH TUESDAY NIGHT...A STRONG MID-LEVEL SHORTWAVE
TROUGH AND AN ACCOMPANYING SFC LOW WILL BE OVER THE SOUTHEAST
ONTARIO AND QUEBEC BORDER AT THE START OF THE PERIOD...AND WILL BE
CONTINUING TO MOVE EAST MONDAY NIGHT. MEANWHILE...MID-LEVEL RIDGING
WILL BE BUILDING INTO THE UPPER MS VALLEY AS A SFC HIGH PRESSURE
SETTLES OVER OVER NW TO CENTRAL WI. MAIN QUESTIONS IN THIS TIME
FRAME REVOLVE AROUND DEPARTING LOW CLOUD COVER IN THE EAST...AND MIN
TEMPS FOR THE WEST.
INCREASINGLY DRIER AIR WILL CONTINUE ADVECTING INTO THE REGION FROM
THE NW AHEAD OF THE SFC HIGH. ATTM...IT APPEARS THAT LOW-CLOUDS
UNDER AN H8 INVERSION SHOULD DISSIPATE ENOUGH FROM INSOLATION AND
INCOMING DRY AIR TO RESULT IN MOSTLY CLEAR SKIES FOR THE WEST HALF.
THE EAST HALF IS A BIT MORE TRICKY...WITH THE NAM NON-SURPRISINGLY
KEEPING LOW STRATUS ACROSS THE AREA WELL INTO THE OVERNIGHT HOURS.
OVERALL...FEELING IS THAT CLOUDS WILL CLEAR OUT BY MIDNIGHT FOR THE
EAST.
WITH THE GRADIENT FLOW WEAKENING ACROSS THE WEST...AND PWAT VALUES
AROUND 0.5 INCHES...GOOD RADIATIONAL COOLING IS EXPECTED. HAVE
FORECAST TEMPS IN THE LOW 40S INTERIOR WEST...WITH EVEN A COUPLE
POCKETS OF UPPER 30S. LOWS SHOULD REMAIN AROUND 50 ALONG THE GREAT
LAKES...AND ACROSS THE EAST HALF WHERE GRADIENT FLOW REMAINS
STRONGER THROUGHOUT THE NIGHT.
BROAD RIDGING MOVES ACROSS THE UPPER GREAT LAKES ON TUESDAY...AND
WILL BRING SUNNY SKIES WITH TEMPS WARMING TO THE MID 70S. RETURN
FLOW ON THE BACKSIDE OF THE SFC HIGH ALONG WITH INCREASING MID-LEVEL
CLOUDS SHOULD KEEP TEMPS FROM FALLING OFF TOO MUCH TUESDAY...WITH
COLDEST LOWS ONLY IN THE UPPER 40S. PLENTY OF DRY AIR ABOVE THE
INVERSION SHOULD ALLOW RH VALUES TO FALL INTO THE MID 30S TO AROUND
40 FOR INTERIOR LOCATIONS...THOUGH WINDS WILL BE QUITE LIGHT.
WEDNESDAY...A STRENGTHENING SHORTWAVE ACROSS NORTHERN CANADA WILL
QUICKLY TRACK SOUTHEAST ACROSS NORTHERN MANITOBA ON TUESDAY...AND
SOUTHERN HUDSON BAY TUESDAY NIGHT INTO WEDNESDAY MORNING. AN
ASSOCIATED STRENGTHENING SFC LOW WILL SEND A COLD FRONT FROM NORTH
TO SOUTH ACROSS THE CWA LATE TUESDAY NIGHT INTO WEDNESDAY. NEARLY
ALL FORCING BY WAY OF MID-LEVEL Q-VECTOR CONVERGENCE WILL STAY WELL
NORTH AND EAST OF THE AREA. GIVEN LIMITED MOISTURE WITH THIS
SYSTEM...DO NOT EXPECT ANYTHING MORE THAN SOME SCATTERED TO BROKEN
MID-LEVEL CLOUDINESS. ONE EXCEPTION COULD BE A BRIEF BOUT OF
POST-FRONTAL UPSLOPE DRIZZLE ACROSS THE NORTH-CENTRAL CWA...BUT WITH
DRY AIR MOVING IN QUICKLY BEHIND THE FRONT...LEFT OUT OF THE FCST
FOR NOW.
THE ECMWF HAS BEEN ON THE FASTER END OF GUIDANCE WITH THE PASSAGE OF
THE FRONT...CLEARING MUCH OF THE CWA BY NOON. THE GFS HAD BEEN
SEVERAL HOURS SLOWER...NOT CLEARING THE CWA UNTIL MID TO LATE
AFTERNOON. HOWEVER...IT HAS TRENDED 3 TO 5 HOURS QUICKER OVER THE
LAST SEVERAL RUNS...AND NOW LINES UP MUCH BETTER WITH THE ECMWF.
WILL FOLLOW THE IDEA OF A QUICKER FRONTAL PASSAGE. STRENGTHENING
HIGH PRESSURE TRACKING SOUTHEASTWARD INTO THE UPPER MS VALLEY BEHIND
THE FRONT WILL INDUCE A MODEST ISALLOBARIC WIND COMPONENT AND BRING
A WINDOW OF BREEZY CONDITIONS WEDNESDAY MORNING...PRODUCING AN
ELEVATED SWIM RISK FOR WEDNESDAY.
WEDNESDAY NIGHT THROUGH SUNDAY...HIGH PRESSURE WILL SETTLE OVER THE
AREA WEDNESDAY NIGHT AND ALLOW TEMPS TO ONCE AGAIN FALL WELL INTO
THE 40S FOR INTERIOR LOCATIONS. DEEP TROUGHING IN THE WEST WILL
DEVELOP BY LATE IN THE WEEK AND DOMINATE THE PATTERN ACROSS THE NE
CONUS. A COUPLE OF WEAK SHORTWAVES WILL TRACK ALONG THE BACKSIDE OF
THIS TROUGH AND AFFECT THE CWA. TIMING AND STRENGTH ARE TYPICALLY
DIFFICULT TO PIN DOWN IN THIS TYPE OF FLOW REGIME...SO WILL USE
CONSENSUS FORECAST THROUGH THE WEEKEND. WITH THAT SAID...BEST CHANCE
TO SEE SOME ISOLATED SHOWERS AND A FEW THUNDERSTORMS WILL BE FRIDAY
AND FRIDAY NIGHT AS A COLD FRONT DROPS SOUTH THROUGH THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 129 AM EDT MON SEP 2 2013
WITH LOW-LEVEL MOISTURE AND CYCLONIC UPSLOPE NNW FLOW OVERNIGHT...
IFR/LOW MVFR CONDITIONS WILL BE THE RULE AT KIWD/KCMX/KSAW. OCNL -DZ
AND -SHRA/SPRINKLES ARE LIKELY AS WELL. AS HIGH PRES BUILDS IN FROM
THE W AND DRIER AIR ADVECTS INTO THE AREA FROM THE N (NOTE CLEARING
OVER NRN ONTARIO ON SATELLITE IMAGERY)...EXPECT GRADUALLY IMPROVING
CONDITIONS FROM W TO E TODAY. IN FACT...CLOUDS SHOULD SCATTER OUT OR
CLEAR COMPLETELY IN THE MID AFTN AT KCMX/KIWD. IT MAY NOT BE UNTIL
LATE AFTN/EARLY EVENING THAT CLOUDS SCATTER OUT AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 401 PM EDT SUN SEP 1 2013
FOLLOWING A COLD FRONTAL PASSAGE LATE THIS AFTERNOON/EARLY
EVENING...EXPECT NNW WINDS UP TO 30 KTS TO DEVELOP OVER THE LAKE AND
CONTINUE INTO MON...WHEN A HI PRES APPROACHING THE UPPER LAKES WILL
CAUSE THE WINDS TO DIMINISH WEST-TO-EAST THRU MON NIGHT. LOOK FOR
LIGHTER WINDS ON TUE AS THE HI PRES MOVES OVER THE UPPER LAKES.
STRONGER NNW WINDS UP TO 25 KTS WILL DEVELOP OVER THE E HALF ON WED
FOLLOWING ANOTHER COLD FRONTAL PASSAGE. THEN WINDS SHOULD DIMINISH
QUICKLY THE REST OF THE WEEK AS ANOTHER HI PRES/WEAK PRES GRADIENT
MOVE OVER THE LAKE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR MIZ005-006.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
849 PM CDT TUE SEP 3 2013
.UPDATE...FRONTAL BOUNDARY CONTINUES TO MAKE SOUTHWARD PROGRESS
ACROSS THE CWA...WITH 60S DEWPOINTS FILTERING IN ACROSS THE HIGHWAY
82 CORRIDOR. SOUTH OF THE FRONT...SCATTERED CONVECTION HAS PERSISTED
WELL INTO THE EVENING ACROSS PORTIONS OF SOUTH MS. A FEW WARNINGS
WERE NEEDED EARLIER THIS EVENING. UPDRAFTS ARE NOT QUITE AS ROBUST
AT THIS POINT...BUT SOME OF THE STORMS ARE STILL PRODUCING QUITE A
BIT OF LIGHTNING AND SOME LOCALLY HEAVY RAINFALL. THE HRRR SUGGESTS
SOME OF THIS ACTIVITY COULD CONTINUE UNTIL AROUND MIDNIGHT...THUS
MINOR ADJUSTMENTS WERE MADE TO POP/WX GRIDS TO KEEP RAIN CHANCES IN
ALONG THE HIGHWAY 84 CORRIDOR LATER INTO THE NIGHT. OTHERWISE...NO
MAJOR CHANGES WILL BE MADE. UPDATES ARE CURRENTLY BEING SHIPPED OUT.
/DL/
&&
.AVIATION...LOOK FOR CONVECTION TO IMPACT THE SE PART OF THE AREA
UNTIL ABOUT 03Z AND CAUSE SOME REDUCED CONDITIONS AT HBG.
ELSEWHERE...THE WEAK SFC BOUNDARY IS APPROACHING I-20 AND THIS WILL
BRING LOWER VALUES OF SFC MOISTURE IN ITS WAKE BEFORE IT STALLS NEAR
I-20 OVERNIGHT. SITES ALONG I-20 COULD SEE A PERIOD OF MVFR VIS
CONDITIONS AFTER 09Z WITH NORTHERN SITES LIKELY STAYING VFR OR
HAVING A SHORTER PERIOD OF MVFR CONDITIONS. LASTLY...HBG COULD SEE A
PERIOD IF IFR CONDITIONS...ESPECIALLY IF THEY RECEIVE PRECIP AND
WILL MENTION THAT IN THE TAFS. ON WED...LOOK FOR VFR CONDITIONS TO
PREVAIL. /CME/
&&
.DISCUSSION... /ISSUED AT 313 PM CDT TUE SEP 3 2013/
SHORT TERM...A WEAK FRONTAL BOUNDARY WILL CONTINUE TO SLOWLY DRIFT
SOUTH TONIGHT AND EXTEND ACROSS THE SOUTHERN PORTIONS OF THE AREA BY
EARLY WEDNESDAY. DRY CONDITIONS WILL PREVAIL ACROSS MOST OF THE AREA
ON WEDNESDAY WITH PWATS FALLING BELOW 1.5 INCHES FOR AREAS ALONG AND
NORTH OF THE I-20 CORRIDOR. ISOLATED AFTERNOON THUNDERSTORM ACTIVITY
WILL MAINLY BE LIMITED TO THE HWY 84 CORRIDOR NEAR THE FRONTAL
BOUNDARY.
LITTLE WILL CHANGE HEADING INTO THURSDAY AND THURSDAY NIGHT...BUT
UPPER HEIGHTS WILL INCREASE OVER THE AREA WITH SLIGHTLY WARMER
AFTERNOON HIGHS IN THE MID 90S. SHOWER AND THUNDERSTORM ACTIVITY
WILL ONCE AGAIN BE LIMITED TO THE SOUTHERN PORTIONS OF THE AREA
THURSDAY AFTERNOON AND EARLY EVENING WHERE PWATS WILL CONTINUE UP
AROUND 1.8-1.9 INCHES. DID NOT MAKE ANY CHANGES TO THE FORECAST
BEYOND THURSDAY NIGHT...SO WILL ATTACH THE PREVIOUS LONG TERM
DISCUSSION BELOW./15/
LONG TERM...THURSDAY THROUGH TUESDAY...THURSDAY MORNING A STALLED
COLD FRONT WILL BE LOCATED IN VICINITY OF THE HIGHWAY 84 CORRIDOR. A
DRIER AIRMASS WITH PWS BELOW AN INCH AND A HALF AND MID 60 SURFACE
DEWPOINTS WILL RESIDE NORTH OF THE FRONT WHILE NEAR TWO INCH PWS AND
LOWER 70 DEW POINTS CONTINUE SOUTH OF THE BOUNDARY. THE NORTHWEST TO
NORTH FLOW AROUND A LARGE AMPLITUDE UPPER LEVEL HIGH CENTERED OVER
THE CENTRAL PLAINS AND THE NORTHEAST FLOW ASSOCIATED WITH A SURFACE
HIGH CENTERED OVER THE GREAT LAKES REGION WILL WORK TOGETHER TO
NUDGE THE STALLED FRONT A LITTLE FARTHER SOUTH FRIDAY AND SATURDAY.
THIS WILL SHIFT RAIN CHANCES SOUTH GOING INTO THE WEEKEND BUT MODEL
CONSENSUS SUGGESTS MAINLY AFTERNOON AND EARLY EVENING RAIN CHANCES
SOUTH OF INTERSTATE 20 THURSDAY THROUGH SATURDAY. WL LEAVE OUT
MENTION OF POPS NORTH OF INTERSTATE 20 THROUGH THE WEEKEND. THE
DRIER AIR MASS WILL LEAD TO BELOW NORMAL MORNING LOWS ACROSS THE
NORTH THURSDAY MORNING AND AGAIN FRIDAY MORNING BUT MORNING
TEMPERATURES WILL CREEP BACK TO NEAR NORMAL BY SATURDAY MORNING.
ABOVE NORMAL AFTERNOON TEMPERATURES WILL CONTINUE THROUGH THE LONG
TERM.
THE LARGE MID LEVEL RIDGE WILL BREAK DOWN SUNDAY INTO MONDAY BUT
SHIFT EAST AND BECOME CENTERED OVER THE MID MISSISSIPPI RIVER VALLEY
BY MONDAY EVENING. THIS COMBINED WITH SURFACE RIDGING DOWN THE MID
ATLANTIC SEABOARD AND BACK ACROSS THE GULF STATES...WILL LIMIT RAIN
CHANCES OVER OUR CWA FOR THE START OF THE WORK WEEK THROUGH TUESDAY.
AFTERNOON HIGHS WILL TOP OUT ABOVE NORMAL THROUGH MUCH OF THE LONG
TERM BUT DEW POINTS MIXING OUT IN THE 60S EACH AFTERNOON WILL OFFSET
ANY HEAT INDEX CONCERNS. /22/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
DL/CME/15/17
AREA FORECAST DISCUSSION
NWS JACKSON MS
1117 AM CDT MON SEP 2 2013
.UPDATE...
HAVE MADE A FEW MORE CHANGES SINCE THE EARLIER UPDATE. THE MOST
SIGNIFICANT UPDATE WAS TO REMOVE THE RISK FOR SEVERE STORMS ALONG
THE HIGHWAY 82 CORRIDOR IN THE GRAPHICS/HWO FOR THIS AFTERNOON/
EVENING. HAVE ALSO SHIFTED BETTER NEAR TERM POPS FARTHER SOUTH AND
CUT BACK ON TODAY`S TEMPERATURES A LITTLE MORE IN CURRENT RAIN AREA.
THE COMPLEX OF SHOWERS/THUNDERSTORMS ACROSS NORTHWEST PORTIONS OF
THE ARKLAMISS HAS DIMINISHED SOME...AND CLOUDS/RAIN ARE KEEP THE
AIRMASS MORE STABLE...THUS LIMITING ANY CONCERN FOR SEVERE STORMS.
HOWEVER...CONTINUED REGENERATION OF CONVECTION ON THE UPSTREAM SIDE
OF THE COMPLEX HAS RAISED SOME CONCERN FOR HEAVY RAINFALL AND MINOR
FLOODING IN THE BOLIVAR/SUNFLOWER COUNTY AREA FOR THE NEXT HOUR OR SO
AND WE ARE MONITORING THIS FOR THE NEAR TERM.
OTHERWISE...SHALLOW OUTFLOW FROM THIS COMPLEX IS MOVING SOUTH WITHOUT
DEEP CONVECTIVE DEVELOPMENT IN THE CAPPED AIRMASS. WITH CONTINUED
DAYTIME HEATING AND DESTABILIZATION...THE RISK FOR STORMS TO DEVELOP
WILL INCREASE ALONG THE BOUNDARY AS IT STALLS SOUTH AND EAST OF THE
CURRENT COMPLEX...BUT THE MOST RECENT HRRR/WRF GUIDANCE CONTINUE TO
BE BEARISH WITH TSTM DEVELOPMENT LATER THIS AFTERNOON/EVENING...SO
HAVE NOT RAISED POPS VERY MUCH. A FEW STRONG PULSE-TYPE STORMS WILL
BE POSSIBLE IF STORMS CAN DEVELOP IN AREAS THAT RECEIVE THE GREATEST
HEATING...ESPECIALLY ALONG AND NORTH OF THE I-20 CORRIDOR. /EC/
&&
.PREV DISCUSSION... /ISSUED 902 AM CDT MON SEP 2 2013/
UPDATE...
A COMPLEX OF SHOWERS/THUNDERSTORMS AFFECTING THE HIGHWAY 82
CORRIDOR...ESPECIALLY IN THE DELTA REGION IS BRINGING HIGH COVERAGE
OF RAINFALL AND HAVE INCREASED POPS TO REFLECT THIS. THE EXPECTATION
IS THAT THIS COMPLEX WILL DIMINISH AS IT MOVES SOUTHEAST INTO A MORE
STABLE MID LEVEL ENVIRONMENT LATER THIS MORNING AND EARLY AFTERNOON.
WITH STRONG AFTERNOON HEATING...STORMS COULD ERUPT ALONG ANY
DIFFERENTIAL/OUTFLOW BOUNDARIES PRODUCED BY THIS COMPLEX...HOWEVER
THE HRRR AND ASSORTMENT OF WRF GUIDANCE ARE STINGY WITH ADDITIONAL
CONVECTIVE DEVELOPMENT LATER THIS AFTN. SO CONFIDENCE IN CONVECTIVE
BEHAVIOR/EVOLUTION TODAY IS LOWER THAN USUAL. /EC/
PREV DISCUSSION... /ISSUED 405 AM CDT MON SEP 2 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT...UPPER RIDGING THAT HAS
BEEN PRESENT OVER OUR REGION THIS WEEKEND WILL CONTINUE TO
RETROGRADE TO THE WEST. IN ADDITION...AN UPPER TROUGH WILL BE
SITUATED ACROSS THE OHIO VALLEY/EASTERN THIRD OF THE UNITED STATES.
THIS WILL LEAVE THE ARKLAMISS REGION BETWEEN THESE TWO UPPER LEVEL
FEATURES AND GENERALLY UNDER NORTHWEST FLOW ALOFT. THIS WILL HELP TO
BRING A SHORTWAVE TROUGH INTO OUR REGION TODAY AHEAD OF A FRONTAL
BOUNDARY. THIS TROUGH LOOKS TO BE RESPONSIBLE FOR THE CONVECTION
CONTINUING ACROSS PORTIONS OF THE MID SOUTH EARLY THIS MORNING.
MODELS INDICATE THAT CONVECTION SHOULD CONTINUE TO DEVELOP THROUGH
THE DAY IN ASSOCIATION WITH THIS SHORTWAVE TROUGH...THE APPROACHING
FRONTAL BOUNDARY...AND LEFTOVER MESOSCALE OUTFLOW BOUNDARIES PRESENT
ACROSS THE AREA. GIVEN COOL MIDLEVEL TEMPERATURES AROUND -6 TO -8C
PRESENT ACROSS THE REGION LEADING TO VERTICAL TOTALS AROUND
28-29C...AMPLE MOISTURE...AND SUFFICIENT DAYTIME HEATING...
CONVECTION WILL INCREASE LATER THIS AFTERNOON ITO THE EVENING. SOME
OF THE STORMS COULD BE SEVERE GIVEN THE BETTER LAPSE RATES AND WILL
CONTINUE TO ADVERTISE THIS POTENTIAL...ESPECIALLY GIVEN THE LABOR
DAY HOLIDAY. THE BEST CONDITIONS APPEAR TO BE NORTH OF I-20 AND
ESPECIALLY NORTH OF HIGHWAY 82 CORRIDOR.
WITH THE FRONTAL BOUNDARY LINGERING ACROSS THE REGION...SHOWERS AND
STORMS WILL LINGER THROUGH THE NIGHT AND INTO TUESDAY ALONG AND
SOUTH OF THE FRONT. BEHIND THE FRONT...DRIER AIR WILL BEING TO
FILTER INTO THE REGION ON TUESDAY. THIS...ALONG WITH COOLER LOW
LEVEL TEMPERATURES...WILL HELP TO MAKE FOR A RATHER PLEASANT DAY ON
TUESDAY FOR LOCATIONS ESPECIALLY NORTH OF I-20/HIGHWAY 82. BY 12Z
WEDNESDAY...MODEL PW VALUES SHOW LOCATIONS SOUTH OF I-20 SEEING
VALUES AROUND 1.5 INCHES...WHEREAS LOCATIONS NORTH OF I-20 WILL BE
AROUND 1-1.3 INCHES. GUIDANCE HAS CONTINUOUSLY BEEN SHOWING MUCH
COOLER TEMPERATURES ON TUESDAY WITH ENSEMBLE MEANS AROUND THE UPPER
80S FOR HIGHWAY 82 CORRIDOR. CONTINUED THE TREND OF CUTTING MAV
GUIDANCE BY A DEGREE OR TWO IN ACCORDANCE WITH THIS AIRMASS BEING
BEHIND THE BOUNDARY. THE MORE NOTICEABLE CHANGE WILL COME IN
OVERNIGHT LOWS. LOWS ON TUESDAY NIGHT WILL BE IN THE MID TO LOWER
60S ACROSS THE NORTHERN COUNTIES. /28/
LONG TERM...WEDNESDAY THROUGH SUNDAY...THE CWA WILL BE DIVIDED IN
HALF THROUGH MUCH OF THE LONG TERM WITH A DRIER AIRMASS AND VERY
LITTLE CHANCE FOR RAIN ACROSS THE NORTH WITH DEEP MOISTURE AND
GREATEST RAIN CHANCES CONTINUING ACROSS THE SOUTH. COME WEDNESDAY
MORNING A LARGE MID LEVEL(595DAM) HIGH WILL BE CENTERED OVER
COLORADO WITH A 1020MB SURFACE RIDGE CENTERED OVER THE TENNESSEE AND
OHIO VALLEYS. A STALLED COLD FRONT IS EXPECTED TO BE DRAPED ACROSS
THE SOUTHERN PORTIONS OF OUR CWA. A DRIER AIRMASS WITH PWS BELOW AN
INCH AND A HALF AND MID 60 SURFACE DEWPOINTS WILL RESIDE NORTH OF
THE FRONT WHILE NEAR TWO INCH PWS AND LOWER 70 DEW POINTS CONTINUE
ACROSS THE SOUTHERN THIRD OF OUR CWA. THIS DRIER AIRMASS WILL LEAD
TO BELOW NORMAL MORNING LOWS ACROSS THE NORTH THROUGH THE END OF THE
WEEK. WARMER THAN NORMAL AFTERNOON HIGHS WILL CONTINUE HOWEVER THE
GFS MOS WAS AMONG THE HIGHEST ENSEMBLE MEMBER AND HAVE LEANED TOWARD
ENSEMBLE MEAN HIGHS THURSDAY THROUGH THE END OF THE WEEK. MAINLY
AFTERNOON AND EARLY EVENING RAIN CHANCES WILL BE CARRIED SOUTH OF
INTERSTATE 20 WEDNESDAY WHILE WL LEAVE OUT MENTION NORTH OF
INTERSTATE 20. VERY LITTLE CHANGE IN SENSIBLE WEATHER IS EXPECTED
OVER OUR AREA THURSDAY BUT A SECOND STRONGER SURFACE HIGH WILL DROP
OUT OF THE NORTHERN PLAINS ACROSS THE GREAT LAKES REGION THURSDAY
NIGHT AND THEN TO THE MID ATLANTIC SEABOARD FRIDAY. THIS WILL
REINFORCE THE DRY NORTH TO NORTHEAST FLOW ACROSS OUR REGION AND
NUDGE THE STALLED FRONTAL BOUNDARY JUST SOUTH OF HIGHWAY 84. DRY
CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE NORTHERN TWO THIRDS
OF OUR CWA BUT MODEL CONSENSUS SUGGESTS CARRYING LOW POPS ACROSS THE
HIGHWAY 84 CORRIDOR FRIDAY AND SATURDAY. THE LARGE MID LEVEL RIDGE
WILL BREAK DOWN SUNDAY INTO MONDAY WHILE WEAK SURFACE RIDGING
BECOMES ORIENTED ALONG THE GULF COAST. DEEPER MO
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS ARE AFFECTING THE GLH-GWO-CBM/GTR CORRIDOR
THIS MORNING. THIS ACTIVITY WILL DIMINISH BY EARLY AFTERNOON...WITH
ISOLATED AFTERNOON STORMS POSSIBLE NEAR TAF SITES THIS AFTERNOON AND
EVENING. OTHERWISE...MORNING MVFR CATEGORIES WILL BE POSSIBLE AGAIN
EARLY TUESDAY MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 96 71 92 68 / 16 36 21 13
MERIDIAN 95 70 92 67 / 20 36 23 8
VICKSBURG 96 69 93 67 / 31 41 22 13
HATTIESBURG 97 73 96 72 / 20 20 32 17
NATCHEZ 96 72 93 71 / 16 25 35 20
GREENVILLE 93 70 92 65 / 64 39 14 11
GREENWOOD 92 69 92 64 / 61 41 13 10
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON MS
902 AM CDT MON SEP 2 2013
.UPDATE...
A COMPLEX OF SHOWERS/THUNDERSTORMS AFFECTING THE HIGHWAY 82
CORRIDOR...ESPECIALLY IN THE DELTA REGION IS BRINGING HIGH COVERAGE
OF RAINFALL AND HAVE INCREASED POPS TO REFLECT THIS. THE EXPECTATION
IS THAT THIS COMPLEX WILL DIMINISH AS IT MOVES SOUTHEAST INTO A MORE
STABLE MID LEVEL ENVIRONMENT LATER THIS MORNING AND EARLY AFTERNOON.
WITH STRONG AFTERNOON HEATING...STORMS COULD ERUPT ALONG ANY
DIFFERENTIAL/OUTFLOW BOUNDARIES PRODUCED BY THIS COMPLEX...HOWEVER
THE HRRR AND ASSORTMENT OF WRF GUIDANCE ARE STINGY WITH ADDITIONAL
CONVECTIVE DEVELOPMENT LATER THIS AFTN. SO CONFIDENCE IN CONVECTIVE
BEHAVIOR/EVOLUTION TODAY IS LOWER THAN USUAL. /EC/
&&
.PREV DISCUSSION... /ISSUED 405 AM CDT MON SEP 2 2013/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT...UPPER RIDGING THAT HAS
BEEN PRESENT OVER OUR REGION THIS WEEKEND WILL CONTINUE TO
RETROGRADE TO THE WEST. IN ADDITION...AN UPPER TROUGH WILL BE
SITUATED ACROSS THE OHIO VALLEY/EASTERN THIRD OF THE UNITED STATES.
THIS WILL LEAVE THE ARKLAMISS REGION BETWEEN THESE TWO UPPER LEVEL
FEATURES AND GENERALLY UNDER NORTHWEST FLOW ALOFT. THIS WILL HELP TO
BRING A SHORTWAVE TROUGH INTO OUR REGION TODAY AHEAD OF A FRONTAL
BOUNDARY. THIS TROUGH LOOKS TO BE RESPONSIBLE FOR THE CONVECTION
CONTINUING ACROSS PORTIONS OF THE MID SOUTH EARLY THIS MORNING.
MODELS INDICATE THAT CONVECTION SHOULD CONTINUE TO DEVELOP THROUGH
THE DAY IN ASSOCIATION WITH THIS SHORTWAVE TROUGH...THE APPROACHING
FRONTAL BOUNDARY...AND LEFTOVER MESOSCALE OUTFLOW BOUNDARIES PRESENT
ACROSS THE AREA. GIVEN COOL MIDLEVEL TEMPERATURES AROUND -6 TO -8C
PRESENT ACROSS THE REGION LEADING TO VERTICAL TOTALS AROUND
28-29C...AMPLE MOISTURE...AND SUFFICIENT DAYTIME HEATING...
CONVECTION WILL INCREASE LATER THIS AFTERNOON ITO THE EVENING. SOME
OF THE STORMS COULD BE SEVERE GIVEN THE BETTER LAPSE RATES AND WILL
CONTINUE TO ADVERTISE THIS POTENTIAL...ESPECIALLY GIVEN THE LABOR
DAY HOLIDAY. THE BEST CONDITIONS APPEAR TO BE NORTH OF I-20 AND
ESPECIALLY NORTH OF HIGHWAY 82 CORRIDOR.
WITH THE FRONTAL BOUNDARY LINGERING ACROSS THE REGION...SHOWERS AND
STORMS WILL LINGER THROUGH THE NIGHT AND INTO TUESDAY ALONG AND
SOUTH OF THE FRONT. BEHIND THE FRONT...DRIER AIR WILL BEING TO
FILTER INTO THE REGION ON TUESDAY. THIS...ALONG WITH COOLER LOW
LEVEL TEMPERATURES...WILL HELP TO MAKE FOR A RATHER PLEASANT DAY ON
TUESDAY FOR LOCATIONS ESPECIALLY NORTH OF I-20/HIGHWAY 82. BY 12Z
WEDNESDAY...MODEL PW VALUES SHOW LOCATIONS SOUTH OF I-20 SEEING
VALUES AROUND 1.5 INCHES...WHEREAS LOCATIONS NORTH OF I-20 WILL BE
AROUND 1-1.3 INCHES. GUIDANCE HAS CONTINUOUSLY BEEN SHOWING MUCH
COOLER TEMPERATURES ON TUESDAY WITH ENSEMBLE MEANS AROUND THE UPPER
80S FOR HIGHWAY 82 CORRIDOR. CONTINUED THE TREND OF CUTTING MAV
GUIDANCE BY A DEGREE OR TWO IN ACCORDANCE WITH THIS AIRMASS BEING
BEHIND THE BOUNDARY. THE MORE NOTICEABLE CHANGE WILL COME IN
OVERNIGHT LOWS. LOWS ON TUESDAY NIGHT WILL BE IN THE MID TO LOWER
60S ACROSS THE NORTHERN COUNTIES. /28/
LONG TERM...WEDNESDAY THROUGH SUNDAY...THE CWA WILL BE DIVIDED IN
HALF THROUGH MUCH OF THE LONG TERM WITH A DRIER AIRMASS AND VERY
LITTLE CHANCE FOR RAIN ACROSS THE NORTH WITH DEEP MOISTURE AND
GREATEST RAIN CHANCES CONTINUING ACROSS THE SOUTH. COME WEDNESDAY
MORNING A LARGE MID LEVEL(595DAM) HIGH WILL BE CENTERED OVER
COLORADO WITH A 1020MB SURFACE RIDGE CENTERED OVER THE TENNESSEE AND
OHIO VALLEYS. A STALLED COLD FRONT IS EXPECTED TO BE DRAPED ACROSS
THE SOUTHERN PORTIONS OF OUR CWA. A DRIER AIRMASS WITH PWS BELOW AN
INCH AND A HALF AND MID 60 SURFACE DEWPOINTS WILL RESIDE NORTH OF
THE FRONT WHILE NEAR TWO INCH PWS AND LOWER 70 DEW POINTS CONTINUE
ACROSS THE SOUTHERN THIRD OF OUR CWA. THIS DRIER AIRMASS WILL LEAD
TO BELOW NORMAL MORNING LOWS ACROSS THE NORTH THROUGH THE END OF THE
WEEK. WARMER THAN NORMAL AFTERNOON HIGHS WILL CONTINUE HOWEVER THE
GFS MOS WAS AMONG THE HIGHEST ENSEMBLE MEMBER AND HAVE LEANED TOWARD
ENSEMBLE MEAN HIGHS THURSDAY THROUGH THE END OF THE WEEK. MAINLY
AFTERNOON AND EARLY EVENING RAIN CHANCES WILL BE CARRIED SOUTH OF
INTERSTATE 20 WEDNESDAY WHILE WL LEAVE OUT MENTION NORTH OF
INTERSTATE 20. VERY LITTLE CHANGE IN SENSIBLE WEATHER IS EXPECTED
OVER OUR AREA THURSDAY BUT A SECOND STRONGER SURFACE HIGH WILL DROP
OUT OF THE NORTHERN PLAINS ACROSS THE GREAT LAKES REGION THURSDAY
NIGHT AND THEN TO THE MID ATLANTIC SEABOARD FRIDAY. THIS WILL
REINFORCE THE DRY NORTH TO NORTHEAST FLOW ACROSS OUR REGION AND
NUDGE THE STALLED FRONTAL BOUNDARY JUST SOUTH OF HIGHWAY 84. DRY
CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE NORTHERN TWO THIRDS
OF OUR CWA BUT MODEL CONSENSUS SUGGESTS CARRYING LOW POPS ACROSS THE
HIGHWAY 84 CORRIDOR FRIDAY AND SATURDAY. THE LARGE MID LEVEL RIDGE
WILL BREAK DOWN SUNDAY INTO MONDAY WHILE WEAK SURFACE RIDGING
BECOMES ORIENTED ALONG THE GULF COAST. DEEPER MO
&&
.AVIATION...
SHOWERS AND THUNDERSTORMS ARE AFFECTING THE GLH-GWO-CBM/GTR CORRIDOR
THIS MORNING. THIS ACTIVITY WILL DIMINISH BY EARLY AFTERNOON...WITH
ISOLATED AFTERNOON STORMS POSSIBLE NEAR TAF SITES THIS AFTERNOON AND
EVENING. OTHERWISE...MORNING MVFR CATEGORIES WILL BE POSSIBLE AGAIN
EARLY TUESDAY MORNING...ESPECIALLY IN AREAS THAT RECEIVE RAINFALL.
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ELKO NV
1018 PM PDT SUN SEP 1 2013
.SYNOPSIS...MONSOON MOISTURE WILL INCREASE ACROSS NEVADA TONIGHT
THROUGH MONDAY...WITH SHOWERS AND THUNDERSTORMS BECOMING
INCREASINGLY LIKELY. SOME STORMS WILL PRODUCE HEAVY RAIN AND
LOCALIZED FLOODING. MONSOON MOISTURE IS EXPECTED TO LINGER FOR
MUCH OF THIS WEEK.
&&
.UPDATE...VORT MAX ASSOCIATED WITH THIS MONSOON PUSH HAS PROVEN
EXTREMELY EFFICIENT...WITH MULTIPLE REPORTS OF FLASH FLOODING
ACROSS THE WATCH AREA AND THUNDERSTORMS CONTINUING TO DEVELOP AT
THIS LATE HOUR. DECIDED TO EXTEND FLASH FLOOD WATCH AN ADDITIONAL
6 HOURS GIVEN CURRENT TRENDS AND LATEST GUIDANCE. FURTHER
ADJUSTMENTS MAY BE FORTHCOMING WITH EARLY MORNING PACKAGE...BUT NO
ADDITIONAL CHANGES WERE MADE AT THIS TIME. RCM
&&
.PREV DISCUSSION... /ISSUED AT 200 PM /
SYNOPSIS...MONSOON MOISTURE WILL INCREASE ACROSS NEVADA TONIGHT
THROUGH MONDAY...WITH SHOWERS AND THUNDERSTORMS BECOMING
INCREASINGLY LIKELY. SOME STORMS WILL PRODUCE HEAVY RAIN AND
LOCALIZED FLOODING. MONSOON MOISTURE IS EXPECTED TO LINGER FOR
MUCH OF THIS WEEK.
SHORT TERM...TONIGHT THROUGH TUESDAY.
AN IMPRESSIVE SURGE OF MONSOON MOISTURE IS ORGANIZING ACROSS
CENTRAL AND SOUTHERN NEVADA THIS AFTERNOON, WHERE YET ANOTHER CROP
OF SCATTERED THUNDERSTORMS IS GETTING UNDERWAY. 12Z NAM AND THE
3KM-HRRR BOTH SPREAD NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE
SOUTHERN HALF OF THE CWA /WHITE PINE, NYE, SOUTHERN LANDER/EUREKA
COUNTIES/ THROUGH THIS EVENING. VISIBLE SATELLITE REVEALS
PERCOLATING CUMULUS ON THE HIGHER TERRAIN OF CENTRAL NEVADA, WITH
SPC MESOANALYSIS REVEALING LIFTED INDEX TO -5 AND CAPE TO
1500 J/KG, AND THAT`S ONLY AS OF NOON. EXTRA MOISTURE IN THE AIR
SEEMS TO BE SLOWING HEATING SOMEWHAT, AND SOME WARMER AIR ALOFT IS
NOT HELPING EITHER. BUT THUNDERSTORMS ARE EXPECTED THROUGH THIS
EVENING NONETHELESS. WILL MAINTAIN FLASH FLOOD WATCH FOR CENTRAL
NEVADA THROUGH 11 PM, WHERE THE GREATEST CONCENTRATION OF STORMS
WILL BE LOCATED. 3KM HRRR FORECASTS A COMPLEX OF THUNDERSTORMS
ENTERING SOUTHERN ELKO COUNTY WITH THE MAIN MOISTURE SURGE AROUND
MIDNIGHT TONIGHT. KEPT SHOWER AND THUNDERSTORM COVERAGE MUCH
HIGHER TONIGHT THAN IS TYPICAL, WITH LOCALLY HEAVY RAIN LIKELY.
WILL LET THE FLASH FLOOD WATCH EXPIRE AT 11 PM FOR NOW, BUT
CONFIDENT THE CONVECTION WILL NOT END THEN, SO THE EVENING SHIFT
WILL NEED TO DETERMINE WHETHER TO EXTEND THE WATCH THROUGH
TONIGHT. MOISTURE QUALITY WILL BE INCREASING DRAMATICALLY TONIGHT
THROUGH MONDAY MORNING, AND WITH GFS/NAM BOTH FORECASTING
SIGNIFICANT INSTABILITY OVERNIGHT INTO MONDAY MORNING, NOCTURNAL
CONVECTION IS LIKELY. FURTHER AIDING THE THUNDERSTORMS WILL BE THE
ADVERTISED WEAK SHORTWAVE, ROTATING NORTH THROUGH EASTERN NEVADA
IN THE MOIST MONSOON FLOW, AND APPROACHING ELKO COUNTY AROUND 5 AM
MONDAY. THIS IS THE MOST STABLE TIME OF DAY /THE CONVECTIVE
MINIMUM/ BUT DESPITE THIS, EXPECT SOME THUNDERSTORMS WILL SURVIVE
THE NIGHT.
WITH THE CLOUDS, RAIN, AND RAPIDLY INCREASING HUMIDITY LOW
TEMPERATURES LABOR DAY MORNING WILL BE VERY MILD AND WAY ABOVE
NORMAL, IN THE UPPER 50S AND LOWER 60S. SOME RECORD WARM OVERNIGHT
LOWS ARE LIKELY, ELKO`S RECORD FOR SEP 2ND IS 59 SET IN 1960. MY
FORECASTED LOW IS 61 DEGREES.
LABOR DAY...CLOUDY AND MOIST WITH SHOWERS AND THUNDERSTORMS
LIKELY. MOISTURE WILL BE PLENTIFUL WITH PRECIPITABLE WATER VALUES
NEAR RECORD LEVELS FOR EARLY SEPTEMBER, RANGING FROM 1-1.2 INCHES.
ANY STORMS THAT DEVELOP MONDAY WILL PRODUCE EXCESSIVE RAINFALL.
THE QUESTION IS, WILL THERE BE ENOUGH INSTABILITY FOR
THUNDERSTORMS TO REDEVELOP MONDAY? THE ANSWER FROM MANY MODELS,
THE 12/18Z NAM, 12Z GFS AND ECMWF IS A UNANIMOUS YES. ALL GUIDANCE
ALLOWS SCATTERED TO NUMEROUS THUNDERSTORMS TO REDEVELOP ACROSS
NEVADA MONDAY AFTERNOON AND EVENING, EVEN ALL THE WAY INTO
HUMBOLDT COUNTY. SOME FORECASTER CONCERNS REGARDING THIS SCENARIO:
1) THE SHORTWAVE THAT WILL HELP TRIGGER STORMS TONIGHT IS COMING
THROUGH NE NEVADA LATE TONIGHT AND EARLY MONDAY, NOT A GREAT TIME
TO GET STORMS GOING. IN FACT, SUBSIDENCE BEHIND THE DEPARTING WAVE
AND THE SINKING AIR ASSOCIATED WITH IT MAY HINDER THUNDERSTORM
GROWTH MONDAY AFTERNOON, AND 2) WE ARE GOING TO BE VERY MOIST.
SKIES WILL BE MOSTLY CLOUDY TO CLOUDY ALL DAY, AND IT MAY PROVE
DIFFICULT TO GET THE SUNSHINE NEEDED FOR NEW STORM INITIATION.
DESPITE THESE CONCERNS, FORECASTED SCATTERED TO NUMEROUS
THUNDERSTORMS FOR ALL ZONES MONDAY. BECAUSE OF THE UNCERTAINTIES,
WILL NOT ISSUE ANOTHER FLASH FLOOD WATCH FOR MONDAY, BUT THIS WILL
REQUIRE CAREFUL WATCHING, ESPECIALLY GIVEN THE OUTDOOR HOLIDAY
ACTIVITIES. FOR NOW, SORT OF TOOK A MIDDLE GROUND AND MENTIONED
HEAVY RAIN IN THE GRIDS FOR NE NEVADA. AGAIN, WITH NEAR RECORD PW
IN THE ATMOSPHERE, ANY STORM WILL PRODUCE VERY HEAVY RAIN.
NOT THE BEST FORECAST FOR LABOR DAY PLANS, BUT DOUBT MANY WILL
COMPLAIN AS THE NEVADA DROUGHT CONTINUES.
TUESDAY...CONTINUED MOIST AND UNSTABLE. PW REMAINS VERY HEALTHY,
RANGING FROM 0.80-1.2 INCH. 12Z GFS FORECASTS WIDESPREAD NEGATIVE
LIFTED INDICES AT 5 PM TUESDAY, SO INCREASED THUNDERSTORM COVERAGE IN
THE GRIDS ACCORDINGLY. TURNER
LONG TERM...TUESDAY NIGHT THROUGH NEXT SUNDAY. MODELS AGREE FAIRLY
WELL WITH THE OVERALL PATTERN THROUGH THE PERIOD. THE CWA IS UNDER
THE INFLUENCE OF THE "MONSOON" MOISTURE TUESDAY NIGHT THROUGH
THURSDAY...HOWEVER UPPER TROF PUSHES INLAND SHOVING THE TSTM
ACTIVITY TO EASTERN NV ON THURSDAY. BY FRIDAY TROF WEAKENS OVER
THE CWA AS IT MOVES NORTH INTO THE PACIFIC NORTHWEST. AGAIN THE
TSTM ACTIVITY IS EXPECTED TO BE CONFINED TO EASTERN NV. BY
SATURDAY INSTABILITY IS PUSHED INTO WHITE PINE COUNTY AS TROF
MOVES TO THE NORTH OF NEVADA. THEN EXPECT DRY CONDITIONS NEXT
SUNDAY AS FOUR CORNER HIGH GETS SUPPRESSED. JH
AVIATION...VFR ALL TERMINALS. KWMC AND KEKO WILL SEE PERIODIC SMOKY
CONDITIONS...BUT IS NOT EXPECTED TO REDUCE SURFACE VSBY. KEKO WILL
ALSO HAVE VCTS THIS EVENING AND MONDAY AFTERNOON. KTPH AND KELY MAY
HAVE -TSRA THROUGH EARLY EVENING. KELY MAY SEE HEAVY RAIN AT
TIMES. JH
FIRE WEATHER...SCATTERED TO NUMEROUS THUNDERSTORMS THIS AFTERNOON
THROUGH MONDAY. WHILE LIGHTNING WILL BE PLENTIFUL, WETTING RAINS
AND MUCH HIGHER RH WILL MINIMIZE THE RISK FOR NEW LIGHTNING
IGNITIONS. RETURNING MONSOON MOISTURE WILL ALLOW FOR MUCH HIGHER
MAX/MIN RH AND GREAT OVERNIGHT RECOVERIES. TURNER
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 5 AM PDT MONDAY FOR NORTHEASTERN NYE
COUNTY...NORTHWESTERN NYE COUNTY...SOUTHERN LANDER COUNTY AND
SOUTHERN EUREKA COUNTY...WHITE PINE COUNTY.
&&
$$
93
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1053 PM EDT TUE SEP 3 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL SHIFT EAST ACROSS SOUTHERN QUEBEC
AND NORTHERN NEW ENGLAND THIS EVENING. HIGH PRESSURE AND DRIER AIR
WILL THEN BUILD ACROSS THE REGION TONIGHT AND WEDNESDAY WITH
CLEARING SKIES. A WEAK COLD FRONT WILL CROSS NEW YORK STATE
WEDNESDAY NIGHT AND BRING A FEW MORE SHOWERS...BEFORE HIGH PRESSURE
AND DRY WEATHER BECOME REESTABLISHED ACROSS OUR AREA FOR THE
REMAINDER OF THE WEEK ALONG WITH A TASTE OF FALL TEMPERATURES.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
WATER VAPOR IMAGERY AND OBJECTIVE RUC ANALYSIS SHOWING THE AXIS OF
THE MID LEVEL TROUGH OVER EASTERN NY LATE THIS EVENING...WITH MOIST
CYCLONIC FLOW QUICKLY MOVING AWAY FROM THE LOWER LAKES. RADAR
IMAGERY SHOWING THE LAST OF THE SCATTERED LAKE EFFECT RAIN SHOWERS
NOW OVER EASTERN OSWEGO AND LEWIS COUNTIES...AND THESE SHOULD END BY
AROUND MIDNIGHT. THE CLEARING LINE IS PROGRESSING QUICKLY EAST
ACROSS THE AREA AND IS LOCATED ALONG A LINE FROM EASTERN LAKE
ONTARIO TO ALLEGANY COUNTY AT 0230Z. AREAS FROM ROCHESTER WEST ARE
ALREADY CLEAR...AND THE REST OF THE AREA WILL CLEAR OUT OVERNIGHT AS
WELL.
LATER TONIGHT THE UPPER TROUGH AXIS AND ASSOCIATED MOISTURE WILL
SLIDE OUT ACROSS NEW ENGLAND...WHILE A SURFACE HIGH MOVES EAST
ACROSS THE OHIO VALLEY. A NARROW SURFACE RIDGE EXTENDING NORTHEAST
FROM THE SURFACE HIGH WILL NOSE TOWARDS THE LOWER LAKES OVERNIGHT...
ALTHOUGH SOME GRADIENT WILL REMAIN IN PLACE PREVENTING WINDS FROM
GOING CALM. THIS SHOULD KEEP FOG BELOW AVERAGE BY EARLY SEPTEMBER
STANDARDS...BUT STILL EXPECT SOME PATCHY FOG IN THE MOST SHELTERED
SOUTHERN TIER VALLEYS.
TEMPERATURE-WISE...EXPECT COMFORTABLY COOL CONDITIONS WITH OVERNIGHT
LOWS SETTLING INTO THE UPPER 40S ACROSS INTERIOR VALLEYS OF THE
SOUTHERN TIER...AND THE LOWER TO MID 50S ELSEWHERE WITH THE
IMMEDIATE LAKESHORES STAYING UP AROUND 60.
ON WEDNESDAY...THE SURFACE HIGH WILL SETTLE SOUTH ACROSS THE MIDDLE
ATLANTIC STATES...WHILE A COLD FRONT MOVES SOUTH TOWARD LAKE ONTARIO
DURING THE AFTERNOON. EXPECT MOSTLY SUNNY SKIES TO PREVAIL BEFORE
MID LEVEL CLOUDS INCREASE LATE IN THE DAY AHEAD OF THE APPROACHING
COLD FRONT. A FEW SHOWERS MAY DEVELOP AHEAD OF THE FRONT AND IMPACT
THE ST LAWRENCE RIVER VALLEY AS WELL AS JEFFERSON AND LEWIS COUNTIES
BY THE LATE AFTERNOON. SOUTHWEST WINDS CHANNELING AHEAD OF THE FRONT
WILL LIKELY RESULT IN RATHER BREEZY CONDITIONS DOWNWIND OF LAKE
ERIE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A COLD FRONT WILL DROP SOUTH ACROSS NEW YORK WEDNESDAY NIGHT
USHERING IN SEASONABLY COOL AND DRY WEATHER FOR THE REMAINDER OF THE
WEEK. MODEL CONSENSUS SHOWS THAT THERE IS A DECENT CHANCE FOR SOME
LIGHT SHOWERS WITH THIS FRONTAL PASSAGE BUT THE ECMWF REMAINS A DRY
OUTLIER. A PEEK AT SURFACE OBSERVATIONS AND SATELLITE IMAGERY FROM
THIS AFTERNOON SHOWS THE FRONT SHIFTING SOUTH ACROSS NORTHWESTERN
ONTARIO CANADA. DECENT MOISTURE IS PRESENT AHEAD OF THE FRONT WITH
DEWPOINTS IN THE 50S SO HAVE LEANED TOWARD MODEL CONSENSUS. HAVE
INCREASED PROBABILITIES FOR SHOWERS TO THE MID CHANCE RANGE AS NOT
ALL LOCATIONS ARE EXPECTED TO SEE MEASURABLE PRECIPITATION. OUTSIDE
OF LIGHT SHOWERS THE FRONT WILL BRING A BAND OF CLOUDS OVERHEAD
WHICH WILL HELP KEEP OVERNIGHT TEMPS ON THE MILD SIDE FOR ONE LAST
NIGHT.
BEHIND THE COLD FRONT...HIGH PRESSURE WILL BEGIN TO BUILD ACROSS THE
LOWER LAKES REGION WITH CENTRAL CANADIAN SOURCED CONTINENTAL POLAR
AIR FLOODING OVER WESTERN AND CENTRAL NEW YORK. THE COOL NORTHWEST
FLOW AND CHILLY TEMPS ALOFT...850MB RANGING FROM 0C TO +3C...WILL
BRING AN EARLY TASTE OF FALL ON THURSDAY. EVEN WITH A DECENT AMOUNT
OF SUNSHINE OUTSIDE OF SOME DIURNAL LAKE EFFECT CLOUDS...AFTERNOON
SURFACE TEMPERATURES WILL STRUGGLE TO CLIMB INTO THE MID 60S. THE
CLEAR SKIES AND DRIER AIR WILL LEAD TO A VERY CHILLY NIGHT THURSDAY
WITH LOWS DIPPING INTO THE 40S AWAY FROM THE LAKES AND EVEN SOME
UPPER 30S POSSIBLE ACROSS THE INLAND SOUTHERN TIER WHERE SOME RIVER
VALLEY FOG WILL BE POSSIBLE. THE SURFACE HIGH WILL CENTER JUST SOUTH
OF NEW YORK ON FRIDAY WITH ANOTHER SEASONABLY COOL BUT MAINLY SUNNY
DAY. TEMPERATURES WILL NOT BE AS COOL AS ON THURSDAY AS SOME WARMER
AIR ALOFT HELPS 850S REBOUND...HIGHS NEAR 70 LOOK ABOUT RIGHT.
FRIDAY NIGHT...LOWS AVERAGE IN THE LOW 50S SO NOT
AS CHILLY AS THE NIGHT BEFORE WITH SOUTHWEST FLOW DEVELOPING AND
SOME CLOUD COVER INCREASING FROM THE WEST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE LONG TERM FORECAST LOOKS TO BE NEARLY A COPY OF THE SHORT TERM
WITH JUST SOME SUBTLE DIFFERENCES. MODELS SHOWING ANOTHER COLD FRONT
DROPPING ACROSS NEW YORK SATURDAY OR SATURDAY NIGHT WITH ANOTHER
CHANCE OF LIGHT RAIN SHOWERS. THE AIRMASS BEHIND THIS WEEKEND FRONT
DOES NOT LOOK AS COLD AS WHAT WE WILL SEE WEDNESDAY NIGHT AND
THURSDAY SO KEPT TEMPERATURES CLOSE TO NORMAL OVER THE WEEKEND.
SUNDAY MAY SEE SOME SHOWERS LINGERING MAINLY TO THE SOUTH AND EAST
BUT OVERALL WE SHOULD SEE HIGH PRESSURE BRINGING A RETURN OF SOME
SUNSHINE LATER SUNDAY AND AGAIN MONDAY. MODEL CONSENSUS SHOWS THE
SURFACE HIGH SHIFTING OFF THE NEW ENGLAND COAST EARLY NEXT WEEK WITH
RETURN MOISTURE BRINGING A CHANCE OF SHOWERS AND A RETURN OF ABOVE
NORMAL TEMPERATURES POSSIBLE AGAIN BY NEXT TUESDAY.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AN EXTENSIVE AREA OF STRATUS AND STRATOCUMULUS OVER THE AREA EARLY
THIS EVENING WILL CLEAR FROM WEST TO EAST TONIGHT AS A TROUGH MOVES
AWAY FROM THE AREA AND IS REPLACED BY A NARROW RIDGE OF HIGH
PRESSURE. UNTIL IT CLEARS...CIGS WITHIN THIS AREA OF CLOUDS WILL
CONTINUE TO BE MAINLY VFR AT LOWER ELEVATIONS WITH SOME MVFR ACROSS
HIGHER TERRAIN. A FEW LAKE EFFECT SHOWERS SOUTHEAST OF LAKES ERIE
AND ONTARIO WILL DISSIPATE LATER THIS EVENING...WITH SPOTTY BRIEF
MVFR VSBY POSSIBLE OVER THE NEXT FEW HOURS. SOME PATCHY VALLEY FOG
WILL FORM LATE TONIGHT AND EARLY WEDNESDAY MORNING IN THE MOST
SHELTERED SOUTHERN TIER VALLEYS...BUT WITH A GRADIENT REMAINING IN
PLACE OVERNIGHT EXPECT COVERAGE AND INTENSITY TO BE BELOW AVERAGE
FOR EARLY SEPTEMBER.
ON WEDNESDAY THE RIDGE OF HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY AND MID ATLANTIC...ALLOWING A WEST TO SOUTHWEST PRESSURE
GRADIENT TO INCREASE. THIS WILL PRODUCE MODERATE WINDS...ESPECIALLY
IN THE AFTERNOON WITH GUSTS IN THE 20-25 KNOT RANGE BECOMING COMMON.
SKIES WILL BE MAINLY CLEAR TO START THE DAY...WITH SOME MINOR
INCREASE IN VFR LEVEL CLOUDS LATER IN THE DAY AHEAD OF ANOTHER COLD
FRONT.
OUTLOOK...
WEDNESDAY NIGHT...VFR/MVFR WITH A CHANCE OF SHOWERS.
THURSDAY AND FRIDAY...VFR.
SATURDAY AND SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.MARINE...
SMALL CRAFT ADVISORY CONDITIONS WILL REMAIN COMMON THROUGH MIDWEEK
ON BOTH LAKES ERIE AND ONTARIO.
ON LAKE ERIE...THE WIND WILL SUBSIDE SOME TONIGHT WITH CONDITIONS
LIKELY FALLING BELOW SMALL CRAFT ADVISORY CRITERIA FOR AWHILE...THEN
PICK UP AGAIN BY LATER WEDNESDAY MORNING AS A COLD FRONT MOVES SOUTH
TOWARD LAKE ONTARIO AND TIGHTENS THE PRESSURE GRADIENT. IN ORDER TO
KEEP THINGS SIMPLE...HAVE JUST GONE WITH ONE SMALL CRAFT ADVISORY
FOR THE ENTIRE PERIOD GIVEN THAT THE TIME OF SUB-SMALL CRAFT
CRITERIA LATER TONIGHT MAY END UP BEING RATHER SHORT.
ON LAKE ONTARIO...THE WIND WILL RELAX A BIT TONIGHT ACROSS THE
WESTERN SHORES OF THE LAKE...BUT THE COMBINATION OF MARGINALLY COLD
OVER THE LAKE AND THE INCREASING PRESSURE GRADIENT AHEAD OF THE
APPROACHING COLD FRONT WILL HELP TO KEEP SMALL CRAFT ADVISORY
CONDITIONS INTACT THROUGH THE NIGHT ACROSS THE EASTERN NEARSHORES.
THIS TREND WILL CONTINUE THROUGH WEDNESDAY AFTERNOON AS THE FRONT
MOVES SOUTH ACROSS THE LAKE. FOLLOWING THE COLD FRONT WEDNESDAY
NIGHT NORTHERLY WINDS WILL CONTINUE IN THE 15-20 KNOT RANGE AND
LIKELY KEEP SMALL CRAFT ADVISORY CONDITIONS GOING RIGHT THROUGH
THURSDAY MORNING.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EDT WEDNESDAY FOR
LEZ020.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THURSDAY FOR
LOZ043-044.
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 4 PM EDT
THURSDAY FOR LOZ042.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT WEDNESDAY FOR LOZ045.
&&
$$
SYNOPSIS...TJP
NEAR TERM...HITCHCOCK/TJP
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HITCHCOCK/TJP
MARINE...HITCHCOCK/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
729 PM EDT TUE SEP 3 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL SHIFT EAST ACROSS SOUTHERN QUEBEC
AND NORTHERN NEW ENGLAND THIS EVENING. HIGH PRESSURE AND DRIER AIR
WILL THEN BUILD ACROSS THE REGION TONIGHT AND WEDNESDAY WITH
CLEARING SKIES. A WEAK COLD FRONT WILL CROSS NEW YORK STATE
WEDNESDAY NIGHT AND BRING A FEW MORE SHOWERS...BEFORE HIGH PRESSURE
AND DRY WEATHER BECOME REESTABLISHED ACROSS OUR AREA FOR THE
REMAINDER OF THE WEEK ALONG WITH A TASTE OF FALL TEMPERATURES.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
WATER VAPOR IMAGERY AND OBJECTIVE RUC ANALYSIS SHOWING THE AXIS OF
THE MID LEVEL TROUGH OVER EASTERN NY THIS EVENING...WITH MOST
CYCLONIC FLOW STILL IN PLACE ACROSS THE LOWER LAKES. THIS IS
ALLOWING PLENTY OF STRATUS TO REMAIN...ALTHOUGH THE CLEARING LINE IS
NOW KNOCKING ON THE DOOR WITH CLEARING ALL THE WAY TO THE NIAGARA
RIVER AS OF 23Z. THE CLEARING WILL SPREAD EAST ACROSS THE AREA THIS
EVENING...ALTHOUGH CLOUDS WILL LIKELY LINGER A LITTLE LONGER ACROSS
THE SOUTHERN TIER AND EAST OF LAKE ONTARIO DUE TO A COMBINATION OF
LAKE EFFECT PROCESSES AND UPSLOPE FLOW.
RADAR IMAGERY STILL SHOWING A FEW SCATTERED LAKE EFFECT RAIN SHOWERS
SOUTHEAST OF BOTH LAKES. THESE WILL LINGER INTO THE EVENING BEFORE
SYNOPTIC SCALE MOISTURE PULLS AWAY AND SUBSIDENCE BEGINS TO TAKE
OVER. EXPECT THE SHOWERS TO BE GONE BY MID EVENING OFF LAKE ERIE AND
BY MIDNIGHT OFF LAKE ONTARIO.
LATER TONIGHT THE UPPER TROUGH AXIS AND ASSOCIATED MOISTURE WILL
SLIDE OUT ACROSS NEW ENGLAND...WHILE A SURFACE HIGH MOVES EAST
ACROSS THE OHIO VALLEY. A NARROW SURFACE RIDGE EXTENDING NORTHEAST
FROM THE SURFACE HIGH WILL NOSE TOWARDS THE LOWER LAKES OVERNIGHT...
ALTHOUGH SOME GRADIENT WILL REMAIN IN PLACE PREVENTING WINDS FROM
GOING CALM. THIS SHOULD KEEP FOG BELOW AVERAGE BY EARLY SEPTEMBER
STANDARDS...BUT STILL EXPECT SOME PATCHY FOG IN THE MOST SHELTERED
SOUTHERN TIER VALLEYS.
TEMPERATURE-WISE...EXPECT COMFORTABLY COOL CONDITIONS WITH OVERNIGHT
LOWS SETTLING INTO THE UPPER 40S ACROSS INTERIOR VALLEYS OF THE
SOUTHERN TIER...AND THE LOWER TO MID 50S ELSEWHERE WITH THE
IMMEDIATE LAKESHORES STAYING UP AROUND 60.
ON WEDNESDAY...THE SURFACE HIGH WILL SETTLE SOUTH ACROSS THE MIDDLE
ATLANTIC STATES...WHILE A COLD FRONT MOVES SOUTH TOWARD LAKE ONTARIO
DURING THE AFTERNOON. EXPECT MOSTLY SUNNY SKIES TO PREVAIL BEFORE
MID LEVEL CLOUDS INCREASE LATE IN THE DAY AHEAD OF THE APPROACHING
COLD FRONT. A FEW SHOWERS MAY DEVELOP AHEAD OF THE FRONT AND IMPACT
THE ST LAWRENCE RIVER VALLEY AS WELL AS JEFFERSON AND LEWIS COUNTIES
BY THE LATE AFTERNOON. SOUTHWEST WINDS CHANNELING AHEAD OF THE FRONT
WILL LIKELY RESULT IN RATHER BREEZY CONDITIONS DOWNWIND OF LAKE
ERIE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A COLD FRONT WILL DROP SOUTH ACROSS NEW YORK WEDNESDAY NIGHT
USHERING IN SEASONABLY COOL AND DRY WEATHER FOR THE REMAINDER OF THE
WEEK. MODEL CONSENSUS SHOWS THAT THERE IS A DECENT CHANCE FOR SOME
LIGHT SHOWERS WITH THIS FRONTAL PASSAGE BUT THE ECMWF REMAINS A DRY
OUTLIER. A PEEK AT SURFACE OBSERVATIONS AND SATELLITE IMAGERY FROM
THIS AFTERNOON SHOWS THE FRONT SHIFTING SOUTH ACROSS NORTHWESTERN
ONTARIO CANADA. DECENT MOISTURE IS PRESENT AHEAD OF THE FRONT WITH
DEWPOINTS IN THE 50S SO HAVE LEANED TOWARD MODEL CONSENSUS. HAVE
INCREASED PROBABILITIES FOR SHOWERS TO THE MID CHANCE RANGE AS NOT
ALL LOCATIONS ARE EXPECTED TO SEE MEASURABLE PRECIPITATION. OUTSIDE
OF LIGHT SHOWERS THE FRONT WILL BRING A BAND OF CLOUDS OVERHEAD
WHICH WILL HELP KEEP OVERNIGHT TEMPS ON THE MILD SIDE FOR ONE LAST
NIGHT.
BEHIND THE COLD FRONT...HIGH PRESSURE WILL BEGIN TO BUILD ACROSS THE
LOWER LAKES REGION WITH CENTRAL CANADIAN SOURCED CONTINENTAL POLAR
AIR FLOODING OVER WESTERN AND CENTRAL NEW YORK. THE COOL NORTHWEST
FLOW AND CHILLY TEMPS ALOFT...850MB RANGING FROM 0C TO +3C...WILL
BRING AN EARLY TASTE OF FALL ON THURSDAY. EVEN WITH A DECENT AMOUNT
OF SUNSHINE OUTSIDE OF SOME DIURNAL LAKE EFFECT CLOUDS...AFTERNOON
SURFACE TEMPERATURES WILL STRUGGLE TO CLIMB INTO THE MID 60S. THE
CLEAR SKIES AND DRIER AIR WILL LEAD TO A VERY CHILLY NIGHT THURSDAY
WITH LOWS DIPPING INTO THE 40S AWAY FROM THE LAKES AND EVEN SOME
UPPER 30S POSSIBLE ACROSS THE INLAND SOUTHERN TIER WHERE SOME RIVER
VALLEY FOG WILL BE POSSIBLE. THE SURFACE HIGH WILL CENTER JUST SOUTH
OF NEW YORK ON FRIDAY WITH ANOTHER SEASONABLY COOL BUT MAINLY SUNNY
DAY. TEMPERATURES WILL NOT BE AS COOL AS ON THURSDAY AS SOME WARMER
AIR ALOFT HELPS 850S REBOUND...HIGHS NEAR 70 LOOK ABOUT RIGHT.
FRIDAY NIGHT...LOWS AVERAGE IN THE LOW 50S SO NOT
AS CHILLY AS THE NIGHT BEFORE WITH SOUTHWEST FLOW DEVELOPING AND
SOME CLOUD COVER INCREASING FROM THE WEST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE LONG TERM FORECAST LOOKS TO BE NEARLY A COPY OF THE SHORT TERM
WITH JUST SOME SUBTLE DIFFERENCES. MODELS SHOWING ANOTHER COLD FRONT
DROPPING ACROSS NEW YORK SATURDAY OR SATURDAY NIGHT WITH ANOTHER
CHANCE OF LIGHT RAIN SHOWERS. THE AIRMASS BEHIND THIS WEEKEND FRONT
DOES NOT LOOK AS COLD AS WHAT WE WILL SEE WEDNESDAY NIGHT AND
THURSDAY SO KEPT TEMPERATURES CLOSE TO NORMAL OVER THE WEEKEND.
SUNDAY MAY SEE SOME SHOWERS LINGERING MAINLY TO THE SOUTH AND EAST
BUT OVERALL WE SHOULD SEE HIGH PRESSURE BRINGING A RETURN OF SOME
SUNSHINE LATER SUNDAY AND AGAIN MONDAY. MODEL CONSENSUS SHOWS THE
SURFACE HIGH SHIFTING OFF THE NEW ENGLAND COAST EARLY NEXT WEEK WITH
RETURN MOISTURE BRINGING A CHANCE OF SHOWERS AND A RETURN OF ABOVE
NORMAL TEMPERATURES POSSIBLE AGAIN BY NEXT TUESDAY.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AN EXTENSIVE AREA OF STRATUS AND STRATOCUMULUS OVER THE AREA EARLY
THIS EVENING WILL CLEAR FROM WEST TO EAST TONIGHT AS A TROUGH MOVES
AWAY FROM THE AREA AND IS REPLACED BY A NARROW RIDGE OF HIGH
PRESSURE. UNTIL IT CLEARS...CIGS WITHIN THIS AREA OF CLOUDS WILL
CONTINUE TO BE MAINLY VFR AT LOWER ELEVATIONS WITH SOME MVFR ACROSS
HIGHER TERRAIN. A FEW LAKE EFFECT SHOWERS SOUTHEAST OF LAKES ERIE
AND ONTARIO WILL DISSIPATE LATER THIS EVENING...WITH SPOTTY BRIEF
MVFR VSBY POSSIBLE OVER THE NEXT FEW HOURS. SOME PATCHY VALLEY FOG
WILL FORM LATE TONIGHT AND EARLY WEDNESDAY MORNING IN THE MOST
SHELTERED SOUTHERN TIER VALLEYS...BUT WITH A GRADIENT REMAINING IN
PLACE OVERNIGHT EXPECT COVERAGE AND INTENSITY TO BE BELOW AVERAGE
FOR EARLY SEPTEMBER.
ON WEDNESDAY THE RIDGE OF HIGH PRESSURE WILL SETTLE INTO THE OHIO
VALLEY AND MID ATLANTIC...ALLOWING A WEST TO SOUTHWEST PRESSURE
GRADIENT TO INCREASE. THIS WILL PRODUCE MODERATE WINDS...ESPECIALLY
IN THE AFTERNOON WITH GUSTS IN THE 20-25 KNOT RANGE BECOMING COMMON.
SKIES WILL BE MAINLY CLEAR TO START THE DAY...WITH SOME MINOR
INCREASE IN VFR LEVEL CLOUDS LATER IN THE DAY AHEAD OF ANOTHER COLD
FRONT.
OUTLOOK...
WEDNESDAY NIGHT...VFR/MVFR WITH A CHANCE OF SHOWERS.
THURSDAY AND FRIDAY...VFR.
SATURDAY AND SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND
THUNDERSTORMS.
&&
.MARINE...
SMALL CRAFT ADVISORY CONDITIONS WILL REMAIN COMMON THROUGH MIDWEEK
ON BOTH LAKES ERIE AND ONTARIO.
ON LAKE ERIE...THE WIND WILL SUBSIDE SOME TONIGHT WITH CONDITIONS
LIKELY FALLING BELOW SMALL CRAFT ADVISORY CRITERIA FOR AWHILE...THEN
PICK UP AGAIN BY LATER WEDNESDAY MORNING AS A COLD FRONT MOVES SOUTH
TOWARD LAKE ONTARIO AND TIGHTENS THE PRESSURE GRADIENT. IN ORDER TO
KEEP THINGS SIMPLE...HAVE JUST GONE WITH ONE SMALL CRAFT ADVISORY
FOR THE ENTIRE PERIOD GIVEN THAT THE TIME OF SUB-SMALL CRAFT
CRITERIA LATER TONIGHT MAY END UP BEING RATHER SHORT.
ON LAKE ONTARIO...THE WIND WILL RELAX A BIT TONIGHT ACROSS THE
WESTERN SHORES OF THE LAKE...BUT THE COMBINATION OF MARGINALLY COLD
OVER THE LAKE AND THE INCREASING PRESSURE GRADIENT AHEAD OF THE
APPROACHING COLD FRONT WILL HELP TO KEEP SMALL CRAFT ADVISORY
CONDITIONS INTACT THROUGH THE NIGHT ACROSS THE EASTERN NEARSHORES.
THIS TREND WILL CONTINUE THROUGH WEDNESDAY AFTERNOON AS THE FRONT
MOVES SOUTH ACROSS THE LAKE. FOLLOWING THE COLD FRONT WEDNESDAY
NIGHT NORTHERLY WINDS WILL CONTINUE IN THE 15-20 KNOT RANGE AND
LIKELY KEEP SMALL CRAFT ADVISORY CONDITIONS GOING RIGHT THROUGH
THURSDAY MORNING.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY FROM 10 AM TO 11 PM EDT WEDNESDAY FOR
LEZ020.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THURSDAY FOR
LOZ043-044.
SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 4 PM EDT
THURSDAY FOR LOZ042.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT WEDNESDAY FOR LOZ045.
&&
$$
SYNOPSIS...TJP
NEAR TERM...HITCHCOCK/TJP
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HITCHCOCK/TJP
MARINE...HITCHCOCK/TJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1216 PM EDT MON SEP 2 2013
.SYNOPSIS...
A COLD FRONT WILL BRING ANOTHER ROUND OF THUNDERSTORMS TO NY AND
PA TODAY. SOME OF THESE STORMS MAY PRODUCE HAIL...GUSTY
WINDS...AND HEAVY RAIN. THE FRONT WILL STALL JUST TO OUR EAST ON
TUESDAY, WITH A CHANCE FOR A FEW SHOWERS OVER OUR REGION. COOLER
AND DRIER WEATHER IS FORECAST FOR MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOON UPDATE...
MORNING WRAP UP AND FLOOD POTENTIAL...QUICK UPDATE WITH A BUSY MORNING BEHIND
US AND AN ACTIVE AFTERNOON EXPECTED. AREA OF CONFECTION FROM THIS
MORNING IS JUST ABOUT TO CLEAR OUR CWA. FLOODING EARLIER ACROSS
SCHUYLER COUNTY NEAR MECKLENBURG IS BEGINNING TO DIMINISH. A CALL
TO THE 911 CENTER LET US KNOW THAT MOST OF THE MAJOR ROADS ARE NOW
OPEN AGAIN BUT STILL ENOUGH ISSUES ON SECONDARY ROADS TO KEEP THE
FLASH FLOOD WARNING UP THROUGH 1245 PM BEFORE LETTING IT EXPIRE.
THIS AREA ALONG WITH FARTHER EAST THROUGH NORTHERN BROOME...AND
PARTS OF CHENANGO COUNTY...ALONG WITH WESTERN LUZERNE (FROM LAST
NIGHTS RAIN) WILL HAVE TO BE CAREFULLY WATCHED FOR FLASH FLOOD
POTENTIAL DUE TO THE SATURATED GROUND. REFER TO THE GRAPHICAL HWO
N OUR WEBSITE (WEATHER.GOV/BGM CLICK ON HAZARDOUS WEATHER OUTLOOK
AT THE TOP THEN FLOODING) TO SEE THE AREAS OF CONCERN. IS IT IMPORTANT
TO NOTE THAT IT WAS THE RATE OF RAINFALL (1.5"+ IN LESS THAN AN
HOUR) THAT LIKELY CAUSED THE PROBLEM. THE STORM TOTAL FROM KBGM
WAS JUST RESET AS IT WAS A RUNNING TOTAL FOR MORE THAN 24 HOURS
AND WE WANTED TO HAVE A CLEAN SLATE FOR THIS AFTERNOON`S
CONVECTION.
AFTERNOON SEVERE THREAT...ISOLATED STORMS HAVE ALREADY POPPED UP
ACROSS BRADFORD COUNTY PA WITH A DECENT CORE ALOFT (HAIL) AND
BACK BUILDING TENDENCIES (FLASH FLOOD THREAT). MEANWHILE MORE CONVECTION
IS EXPECTED TO FIRE OVER WNY AHEAD OF A COLD FRONT. WIND SHEAR IS
THE ONLY LIMITING FACTOR AT AROUND 25 KTS FOR 0-6 KM SHEAR.
WE HAVE PLENTY OF DYNAMICAL FORCING WITH THE SURFACE FRONT AND
UPPER LEVEL TROF SWINGING THROUGH TO COMPENSATE FOR THE WEAKER
SHEAR. IN ADDITION SBCAPES ARE OVER 2000 J/KG THANKS TO INCREASING
SUNSHINE AND A VERY MOIST ENVIRONMENT. OUR LOCAL SEVERE WEATHER CHECKLIST
POINTS TO A HAIL DAY WITH VERY DRY AIR IN THE MID LEVELS AND
STRONG MID LEVEL LAPSE RATES. WITH HAIL BEING THE NUMBER 1
THREAT...WIND IS NOT FAR BEHIND DUE TO THE DRY AIR IN THE MID
LEVELS AND WE MENTIONED FLASH FLOODING THREAT ABOVE. EXPECT
ISOLATED TO SCT. CONVECTION NEXT FEW HOURS...THEN BKN LINES OF
STORMS TO DEVELOP BETWEEN 18Z AND 21Z OVER THE FINGER LAKES BEFORE
MOVING SOUTH AND EAST. THE HRRR AND ARW SEEM TO HAVE A DECENT
HANDLE ON THIS SCENARIO IF YOU WANT A GRAPHICAL VIEW.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
COLD FRONT WILL STALL TO OUR EAST ON TUESDAY AS UL TROF SAGS
SOUTHEASTWARD OUT OF ONTARIO AND INTO NORTHERN NY. DESPITE DRY AIR
ADVECTION, THE PRESENCE OF THE TROF WILL KEEP A FEW SHOWERS OVER
FA THROUGH THE AFTERNOON HOURS.
BY EARLY WEDNESDAY, WE FINALLY GET ON THE WESTERN EDGE OF THE TROF
AXIS. PRECIP WILL SHIFT EASTWARD TO THE COAST, WHILE SKIES WILL
BEGIN TO CLEAR OVER NY/PA. THE COOL POOL ALOFT WILL BE DIRECTLY
OVERHEAD, KEEPING TEMPS IN THE LOWER 70S FOR MUCH OF THE FA.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
3 AM UPDATE...
NO CHGS NEEDED TO LONG TERM AT THIS TIME AS UL RIDGE HOLDS ACRS
WRN U.S. THRU SUNDAY BEFORE STARTING TO FLATTEN OUT EARLY NEXT
WEEK.
250 PM UPDATE...
A FAIRLY QUIET EXTENDED PERIOD WITH A FEW WEAK FRONTAL BOUNDARIES
BRINGING CHCS FOR PRECIP. FIRST BOUNDARY EARLY IN THE PD WILL
BRING JUST SLGT CHCS FOR SHRA MAINLY TO NRN PORTION OF FA WED
NGT/EARLY THURS. ANOTHER CLD FRONT SATURDAY MAY BRING SOMEWHAT
BETTER CHCS FOR PRECIP. MAIN STORY LATER THIS WEEK WILL BE COOLER
AIRMASS WITH HIGHS PSBLY NOT GETTING OUT OF THE 60S FOR A LARGE
PART OF THE FA ON THURSDAY WITH LOWS DROPPING WELL INTO THE 40S
FRIDAY MORNING. BEYOND THAT, TEMPS MODERATE TO NEAR OR SLIGHTLY
ABOVE FOR HIGHS BY THE WEEKEND AS SFC HIGH PRESSURE MOVES OVER AND
THEN SE OF THE REGION.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
12Z UPDATE...
CONDITIONS RANGE FROM VFR TO LIFR AS AIRMASS SATURATED FROM RAIN
LAST NIGHT RESULTS IN DENSE FOG DEVELOPMENT AT SOME TERMINALS.
HOWEVER TERMINALS THAT ARE CURRENTLY BEING AFFECTED BY SHOWERS
HAVE IMPROVING CONDITIONS. KBGM AND KAVP ARE CURRENTLY AT IFR AND
WILL REMAIN THERE THROUGH 13Z THIS MORNING. AT KITH AND KELM
EXPECT MVFR CONDITIONS IN LIGHT SHRA THROUGH 14Z WITH KSYR AND
KRME REMAINING VFR.
CONDITIONS IMPROVE TO A BKN-OVC VFR DECK AFTER 15Z AT ALL
TERMINALS ALONG WITH A BRIEF BREAK IN THE RAIN. COLD FRONT WILL
APPROACH FROM THE NORTHWEST AFTER 20Z THIS AFTERNOON WITH MVFR
RESTRICTIONS POSSIBLE. FOLLOWING FRONTAL PASSAGE EXPECT TERMINALS
TO DROP TO MVFR OVERNIGHT.
LGT/VRB WINDS THIS MORNING WILL BECOME MORE SWRLY AROUND 5KTS
DURING THE DAY SHIFTING TO THE NORTHWEST TOWARD MIDNIGHT.
OUTLOOK...
TUE...POTENTIAL FOR MVFR IN SCT SHRA.
WED-FRI...MAINLY VFR WITH POTENTIAL MORNING RESTRICTIONS DUE TO
FOG.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJP/HEDEN
NEAR TERM...DJP/HEDEN
SHORT TERM...DJP
LONG TERM...JML/PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
249 PM EDT MON SEP 2 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TONIGHT...
THEN PUSH SLOWLY SOUTHEAST THROUGH THE CAROLINAS ON TUESDAY. IN THE
WAKE OF THE FRONT...HIGH PRESSURE WILL BUILD INTO THE REGION ON
WEDNESDAY AND LINGER THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1220 PM MONDAY...
OVERVIEW:
CYCLONIC FLOW ALOFT WILL PERSIST ACROSS THE CAROLINAS AND
MID-ATLANTIC THROUGH TONIGHT AS A POTENT UPPER LEVEL LOW TRACKS
SLOWLY EAST FROM THE UPPER GREAT LAKES TOWARD QUEBEC/NEW ENGLAND. AN
ASSOCIATED COLD FRONT...EXTENDING SOUTHWEST FROM THE LOWER GREAT
LAKES TO THE LOWER MS RIVER VALLEY THIS MORNING...WILL TRACK SLOWLY
SOUTHEAST TO THE SOUTHERN APPALACHIANS TONIGHT.
INSTABILITY:
EXPECT MODERATE TO PERHAPS STRONG DESTABILIZATION BY PEAK HEATING
THIS AFTERNOON AS STEEPER MID-LEVEL LAPSE RATES (6.0-7.0 C/KM)
ADVECT INTO THE REGION FROM THE N/NW ATOP A WARM/MOIST LOW-LEVEL
AIRMASS. A SMALL (BUT NOTICEABLE) DEWPOINT DISCONTINUITY WILL
PERSIST ACROSS THE SANDHILLS AND COASTAL PLAIN TODAY...WITH SFC
DEWPOINTS 73-75F ALONG AND EAST OF A LINE FROM RCZ-FBG-RWI.
INSOLATION COMBINED WITH THE AFOREMENTIONED MOISTURE IN THE
SANDHILLS/SE COASTAL PLAIN HAS RESULTED IN COMPLETE EROSION OF CINH
AND 1500 J/KG MLCAPE AS OF 15Z...AND THIS AREA SHOULD SEE MLCAPE
VALUES OF 2000-3000 J/KG BY PEAK HEATING. IN THE N/NW PIEDMONT...
DESPITE A SLIGHTLY DRIER LOW-LEVEL AIRMASS...STEEPER MID-LEVEL LAPSE
RATES SHOULD CONTRIBUTE TO MODERATE DESTABILIZATION WITH MLCAPE
VALUES OF 1000-2000 J/KG. A DRIER MID-LEVEL AIRMASS ASSOCIATED WITH
THE MODIFIED EML ADVECTING INTO THE MID-ATLANTIC WILL CONTRIBUTE TO
HIGHER DCAPE IN COMPARISON TO PREVIOUS DAYS...RANGING FROM 750-1250
J/KG AT PEAK HEATING...HIGHEST ALONG AND JUST EAST OF HWY 1.
PRECIP CHANCES:
EXTREMELY CHALLENGING FORECAST. SHALLOW CONVERGENCE ASSOCIATED WITH
A LOW-LEVEL TROUGH OVER THE COASTAL PLAIN WILL BE PRESENT THROUGH
EARLY AFTERNOON...THOUGH THIS CONVERGENCE ZONE MAY EFFECTIVELY
RETROGRADE TO THE HWY 1 CORRIDOR LATER THIS AFT/EVE AS LOW-LEVEL
FLOW OVER WESTERN NC BACKS FROM NW-W IN ASSOC/W VERY WEAK HEIGHT
FALLS AND INCREASING CYCLONIC SHEAR VORTICITY ACROSS THE
MID-ATLANTIC. 15Z WV IMAGERY AND RAP DATA SUGGESTS THAT A SMALL
AMPLITUDE SHORTWAVE (OR AN MCV SPAWNED BY UPSTREAM CONVECTION
EARLIER THIS MORNING) IS PRESENT IN VICINITY OF THE CLT METRO AREA.
THIS FEATURE APPEARS TO BE ENHANCING CLOUD COVER ACROSS THE W/SW
PIEDMONT...AND A SLIGHT `SWIRL` IS EVEN DISCERNIBLE IN VIS SAT
IMAGERY. ENHANCED CLOUD COVER ASSOC/W THIS FEATURE IS ALREADY
CREATING A DIFF HEATING BOUNDARY ACROSS THE SW PIEDMONT AND
SANDHILLS...FURTHER COMPLICATING THE FORECAST. REGARDLESS...THIS
FEATURE COULD PROVIDE SUFFICIENT FORCING FOR CONVECTIVE DEVELOPMENT
BETWEEN 16-21Z IN THE SANDHILLS AND SE COASTAL PLAIN...ESPECIALLY
GIVEN MODERATE TO STRONG INSTABILITY AND LITTLE/NO CINH. AT THE SAME
TIME...SUBSIDENCE IN THE WAKE OF THIS FEATURE COULD SUPPRESS
CONVECTIVE DEVELOPMENT IN THE W/NW PIEDMONT THROUGH MID/LATE
AFTERNOON. GIVEN CYCLONIC FLOW ALOFT IT IS CERTAINLY POSSIBLE THAT
ADDITIONAL DISTURBANCES WILL PROGRESS ACROSS THE REGION LATER THIS
EVENING/TONIGHT...THOUGH SUCH FEATURES COULD ALSO RESULT IN
SUBSIDENCE /SUPPRESSED DEVELOPMENT/ DEPENDING ON THE TRACK...TIMING
AND LOCATION. WITH THE ABOVE IN MIND...WILL INDICATE PRECIP CHANCES
RANGING FROM 30-50%...LOWEST IN THE W/NW PIEDMONT AND HIGHEST IN THE
SANDHILLS/SE COASTAL PLAIN.
TEMPERATURES:
EXPECT HIGHS TODAY RANGING FROM THE MID/UPPER 80S IN THE WESTERN
PIEDMONT TO THE LOWER 90S IN THE COASTAL PLAIN...PRIMARILY DEPENDING
ON CLOUD COVER. LOWS TONIGHT SIMILAR TO LAST NIGHT IN THE LOWER 70S.
SEVERE THREAT:
THOUGH DEEP-LAYER SHEAR REMAINS WEAK (15-20 KT) AND SIMILAR TO
YESTERDAY...STEEPER MID-LEVEL LAPSE RATES (6.0-7.0 C/KM)...MODERATE
INSTABILITY...AND A DRIER MID-LEVEL AIRMASS/HIGHER DCAPE (750 TO
1250 J/KG) WOULD SUGGEST MORE ROBUST COLD POOLS AND A BETTER
POTENTIAL FOR DAMAGING WINDS WITH DEEP CONVECTION THIS AFT/EVE.
GIVEN ABOVE NORMAL UNCERTAINTY WITH REGARD TO CONVECTIVE COVERAGE...
THE THREAT WILL BE CONDITIONAL IN NATURE...ESPECIALLY ACROSS THE
N/NW PIEDMONT WHERE THE THERMODYNAMIC ENVIRONMENT WILL BE MORE
SUPPORTIVE BUT CONVECTIVE INITIATION WILL BE MORE QUESTIONABLE. WILL
MENTION A CHANCE OF ISOLD SVR STORMS IN THE HWO ALONG/EAST OF HWY 1
THIS AFT/EVE WHERE DEVELOPMENT APPEARS MORE LIKELY. -VINCENT
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 245 PM MONDAY...
CYCLONIC FLOW ALOFT WILL STRENGTHEN OVER THE CAROLINAS ON TUE AS AN
UPPER LEVEL LOW TRACKS EAST INTO QUEBEC/NEW ENGLAND. THE BEST DPVA
AND HEIGHT FALLS WILL REMAIN WELL NORTH OF CENTRAL NC...THOUGH SMALL
AMPLITUDE DISTURBANCES EMBEDDED IN INCREASINGLY NW FLOW ALOFT WILL
REMAIN POSSIBLE THROUGHOUT THE DAY. IN THE LOWER LEVELS...A
LOW-LEVEL TROUGH AND SFC COLD FRONT IS PROGGED TO TRACK SOUTHEAST TO
THE HWY 1 CORRIDOR BY EARLY AFTERNOON...PROGRESSING SLOWLY SOUTHEAST
TOWARD THE CAROLINA COAST BY MIDNIGHT. ANTICIPATE MODERATE DIURNAL
DESTABILIZATION ALONG/EAST OF HWY 1 ON TUE...WITH AT LEAST MARGINAL
INSTABILITY IN THE NW PIEDMONT. GIVEN A GOOD LOW-LEVEL FOCUS
COINCIDING WELL WITH PEAK HEATING (ALONG/EAST OF HWY 1 AT LEAST)...
CYCLONIC FLOW ALOFT...PWAT VALUES OF 1.50-1.75" AND MARGINAL TO
MODERATE INSTABILITY...WILL INDICATE PRECIP CHANCES RANGING FROM
20-30% N/NW PIEDMONT TO 50-60% IN THE SANDHILLS AND SE COASTAL PLAIN
DURING THE AFTERNOON HOURS...WITH CHANCES DECREASING AND EVENTUALLY
ENDING FROM NW-SE TUE EVENING AS THE FRONT PROGRESSES TOWARD THE
COAST AND A DRIER AIRMASS ADVECTS INTO CENTRAL NC. WILL INDICATE DRY
CONDITIONS AFTER MIDNIGHT. EXPECT HIGHS TUE SLIGHTLY COOLER THAN
TODAY...IN THE MID/UPPER 80S (N/NW) TO LOWER 90S (S/SE). LOWS TUE
NIGHT WILL DEPEND PRIMARILY ON THE TIMING OF THE FRONT...THE
ADVECTION OF A DRIER AIRMASS INTO CENTRAL NC FROM THE NORTH...AND
CLEARING. WILL INDICATE LOWS RANGING FROM THE LOWER/MID 60S N/NW TO
UPPER 60S /NEAR 70F/ S/SE. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 245 PM MONDAY...
WEDNESDAY THROUGH THURSDAY...THERE IS LITTLE LIFT ON BOTH THE NAM
AND THE GFS BOTH WEDNESDAY AND THURSDAY...WITH ONLY WEAK MID-LEVEL
WAVES MOVING THROUGH IN THE NORTHWEST FLOW ALOFT. PRECIPITABLE WATER
VALUES ARE LOWER THAN HAVE BEEN THE AVERAGE OF LATE...THE HIGHEST
AMOUNTS BEING JUST ABOVE 1.5 INCHES IN THE SANDHILLS AND SOUTHERN
COASTAL PLAIN THURSDAY WHICH IS AT THE HIGH END OF THE NORMAL RANGE
FOR EARLY SEPTEMBER. WHILE MIXED-LAYER CAPE IN THE LOWEST KM IS
1000-1500J/KG MAINLY ALONG AND SOUTH OF U.S. 64 BOTH WEDNESDAY AND
THURSDAY...BUFR SOUNDINGS FROM THE NAM AND GFS ARE GENERALLY STABLE
TO DEEP CONVECTION BOTH DAYS. THE NAM HAS NO QPF WEDNESDAY...WHILE
THE GFS HAS MEAGER QPF IN CENTRAL NORTH CAROLINA OUTSIDE OF THE
TRIAD. WITH THE WEAKENING AND SLOWING INITIAL SURFACE FRONT SOUTH OF
THE AREA WEDNESDAY...WEAK 850MB CONVERGENCE JUST SOUTH OF THE AREA
AS WELL...LITTLE FORCING ALOFT...AND LAPSE RATES ALOFT NEAR OR JUST
TO THE WARM SIDE OF MOIST ADIABATIC ON BUFR SOUNDINGS...THINK THAT
OUTSIDE OF AN ISOLATED SHOWER WEDNESDAY WHICH WOULD BE MORE LIKELY
IF IT WOULD OCCUR TOWARD THE SOUTHEAST...CHANCES FOR PRECIPITATION
SEEM SMALL. WEDNESDAY NIGHT INTO THURSDAY...NAM AND GFS BUFR
SOUNDINGS SHOW SLIGHT COOLING ALOFT LATE AT NIGHT INTO MIDDAY
THURSDAY BEFORE THE MID-LEVELS WARM AGAIN AS THE DAY WEARS ON. WHILE
THE NAM IS AGAIN DRY...THE GFS QPF SHOWS A SMATTERING OF LIGHT
PRECIPITATION IN CENTRAL NORTH CAROLINA IN WHICH AN ISOLATED SHOWER
OR TWO IS PLAUSIBLE LATE IN THE MORNING INTO MID AFTERNOON IF THE
SUBTLE COOLING ON THE KRDU GFS BUFR SOUNDING JUST LEFT OF MOIST
ADIABATIC VERIFIES. WHILE CERTAINLY NOT RULING OUT AN ISOLATED
SHOWER THURSDAY...WILL CONTINUE WITH THE DRY WORDED FORECAST AND A
GRIDDED PRECIPITATION FORECAST OF TEN PERCENT.
HIGH TEMPERATURES WILL BE FORECAST CLOSE TO WHAT THE 1000-850MB
THICKNESSES AND A BLEND OF MOS GUIDANCE WOULD IMPLY...MID 80S TO
AROUND 90 BOTH WEDNESDAY AND THURSDAY. WEDNESDAY NIGHT LOWS WILL BE
IN THE 60S. UNDER A LIGHT WIND AND WITH THE WEAK SURFACE FRONT JUST
SOUTH OF THE AREA...THE AIR MASS SHOULD REMAIN FAIRLY MOIST
PARTICULARLY OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN. GUIDANCE
IS IN AGREEMENT ABOUT THE POTENTIAL FOR AT LEAST PATCHY FOG
ESPECIALLY EAST OF U.S. 1 LATE WEDNESDAY NIGHT AND THURSDAY MORNING
AND WILL NOTE THIS IN THE FORECAST.
THURSDAY NIGHT THROUGH MONDAY...A GENERAL NORTHWEST FLOW ALOFT
REMAINS IN PLACE DURING THIS PART OF THE LONG-TERM PERIOD...WITH THE
TROUGH AXIS ALOFT OVERHEAD FOR THE WEEKEND. A VERY MODEST INCREASE
IN HEIGHTS ALOFT IS ALLUDED TO TOWARD THE END OF THIS PERIOD IN THE
LONG-TERM GUIDANCE...WITH MAINLY LIGHT WINDS ALOFT. GUIDANCE POPS
ARE IN THE ISOLATED-TO-SCATTERED RANGE...LEAST EARLY WITH A MODEST
TREND HIGHER LATER IN THE PERIOD. THIS SEEMS REASONABLE...AS BEHIND
A SECOND SURFACE FRONT THURSDAY NIGHT SURFACE HIGH PRESSURE BUILDS
IN WHICH SHOULD ALLOW FOR INCREASED STABILITY FOR THE END OF THE
WEEK AND THE START OF THE WEEKEND...WHEN THE FORECAST WILL LARGELY
BE DRY. WILL RETAIN THE SLIGHT CHANCE INHERITED IN THE FORECAST FOR
SATURDAY TOWARD THE YADKIN RIVER...CERTAINLY NOT EXPANDING FURTHER
AS COARSE MODEL SOUNDINGS FROM THE GFS AND ECMWF ARE FAIRLY STABLE
EVEN INTO SATURDAY...BUT THEN MODEST CHANCES INCREASE THROUGHOUT
CENTRAL NORTH CAROLINA SUNDAY INTO MONDAY COURTESY OF A WARMER AIR
MASS WITH A GRADUAL INCREASE IN LOW-LEVEL MOISTURE AND LAPSE RATES
ALOFT ON THE COARSE MODEL SOUNDINGS. WITH NO SIGNIFICANT FORCING
APPARENT REGARDING SURFACE FEATURES OR IN THE MID-LEVELS...ANY DEEP
CONVECTION SHOULD TEND TO BE ISOLATED-TO-SCATTERED AND MAINLY
DIURNAL IN NATURE.
AS HIGH PRESSURE BUILDS IN FRIDAY...THE GRADIENT APPEARS TIGHT
ENOUGH THAT IT COULD BE SOMEWHAT BREEZY INITIALLY WITH MIXING. UNDER
A NORTHEAST FLOW IN THE LOW LEVELS...THE LONG-TERM GUIDANCE HAS BEEN
CONSISTENT SHOWING AT LEAST MODEST UPPER-LEVEL MOISTURE...BOTH OF
WHICH COULD LIMIT THE TEMPERATURE RISE. HAVE TRENDED LOWER WITH THE
HIGHS FOR FRIDAY...AND SOME GUIDANCE SUGGESTS HIGHS WILL STRUGGLE TO
GET TO 80 ESPECIALLY NORTH OF U.S. 64 FRIDAY AFTERNOON. ALSO LOWERED
MINS FOR FRIDAY NIGHT DIRECTLY UNDER SURFACE HIGH PRESSURE AND A
LIGHT WIND EXPECTED...WITH SOME READINGS POSSIBLY INTO THE LOWER TO
MID 50S NORTHEAST OF THE TRIANGLE. EXPECT A GRADUAL WARMING TREND
FOR BOTH HIGHS AND LOWS SATURDAY THROUGH MONDAY...NORMAL TO JUST
ABOVE NORMAL BY THE END OF THE FORECAST PERIOD AS 1000-850MB
THICKNESSES RISE AND FOLLOWING THE TREND OF THE CONSENSUS OF THE
BIAS-CORRECTED TEMPERATURE GUIDANCE.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1130 AM MONDAY...
24-HR TAF PERIOD:
AFTER LINGERING MVFR CEILINGS THIS MORNING LIFT TO VFR BY 16Z...
EXPECT VFR CONDITIONS TO GENERALLY PREVAIL THROUGH EARLY TO MID
AFTERNOON. ANTICIPATE AN INCREASING CHANCE FOR SHOWERS AND
THUNDERSTORMS AT ALL TERMINALS FROM MID/LATE AFTERNOON THROUGH THIS
EVENING...WITH THE RELATIVE BEST CHANCE AT THE RDU/FAY/RWI
TERMINALS. AN ISOLD SVR STORM WITH SFC WIND GUSTS AS HIGH AS 35-50
KT CANNOT BE RULED OUT. OTHERWISE...EXPECT A POTENTIAL FOR SUB-VFR
FOG OR CEILINGS ONCE AGAIN EARLY TUE MORNING (08-14Z).
LOOKING AHEAD:
A CHANCE OF SHOWERS/STORMS WILL PERSIST ON TUE AS A COLD FRONT
TRACKS SOUTHEAST ACROSS CENTRAL NC...WITH THE BEST CHANCE AT THE
EASTERN TERMINALS (RDU/FAY/RWI) DURING THE AFTERNOON AND EARLY
EVENING. ASIDE FROM A SMALL CHANCE FOR FOG AT THE FAY/RWI TERMINALS
AROUND SUNRISE (08-12Z) EACH MORNING...EXPECT VFR CONDITIONS WED-FRI
AS HIGH PRESSURE BUILDS INTO THE REGION. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...DJF
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1224 PM EDT MON SEP 2 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TONIGHT...
THEN PUSH SLOWLY SOUTHEAST THROUGH THE CAROLINAS ON TUESDAY. IN THE
WAKE OF THE FRONT...HIGH PRESSURE WILL BUILD INTO THE REGION ON
WEDNESDAY AND LINGER THROUGH THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1220 PM MONDAY...
OVERVIEW:
CYCLONIC FLOW ALOFT WILL PERSIST ACROSS THE CAROLINAS AND
MID-ATLANTIC THROUGH TONIGHT AS A POTENT UPPER LEVEL LOW TRACKS
SLOWLY EAST FROM THE UPPER GREAT LAKES TOWARD QUEBEC/NEW ENGLAND. AN
ASSOCIATED COLD FRONT...EXTENDING SOUTHWEST FROM THE LOWER GREAT
LAKES TO THE LOWER MS RIVER VALLEY THIS MORNING...WILL TRACK SLOWLY
SOUTHEAST TO THE SOUTHERN APPALACHIANS TONIGHT.
INSTABILITY:
EXPECT MODERATE TO PERHAPS STRONG DESTABILIZATION BY PEAK HEATING
THIS AFTERNOON AS STEEPER MID-LEVEL LAPSE RATES (6.0-7.0 C/KM)
ADVECT INTO THE REGION FROM THE N/NW ATOP A WARM/MOIST LOW-LEVEL
AIRMASS. A SMALL (BUT NOTICEABLE) DEWPOINT DISCONTINUITY WILL
PERSIST ACROSS THE SANDHILLS AND COASTAL PLAIN TODAY...WITH SFC
DEWPOINTS 73-75F ALONG AND EAST OF A LINE FROM RCZ-FBG-RWI.
INSOLATION COMBINED WITH THE AFOREMENTIONED MOISTURE IN THE
SANDHILLS/SE COASTAL PLAIN HAS RESULTED IN COMPLETE EROSION OF CINH
AND 1500 J/KG MLCAPE AS OF 15Z...AND THIS AREA SHOULD SEE MLCAPE
VALUES OF 2000-3000 J/KG BY PEAK HEATING. IN THE N/NW PIEDMONT...
DESPITE A SLIGHTLY DRIER LOW-LEVEL AIRMASS...STEEPER MID-LEVEL LAPSE
RATES SHOULD CONTRIBUTE TO MODERATE DESTABILIZATION WITH MLCAPE
VALUES OF 1000-2000 J/KG. A DRIER MID-LEVEL AIRMASS ASSOCIATED WITH
THE MODIFIED EML ADVECTING INTO THE MID-ATLANTIC WILL CONTRIBUTE TO
HIGHER DCAPE IN COMPARISON TO PREVIOUS DAYS...RANGING FROM 750-1250
J/KG AT PEAK HEATING...HIGHEST ALONG AND JUST EAST OF HWY 1.
PRECIP CHANCES:
EXTREMELY CHALLENGING FORECAST. SHALLOW CONVERGENCE ASSOCIATED WITH
A LOW-LEVEL TROUGH OVER THE COASTAL PLAIN WILL BE PRESENT THROUGH
EARLY AFTERNOON...THOUGH THIS CONVERGENCE ZONE MAY EFFECTIVELY
RETROGRADE TO THE HWY 1 CORRIDOR LATER THIS AFT/EVE AS LOW-LEVEL
FLOW OVER WESTERN NC BACKS FROM NW-W IN ASSOC/W VERY WEAK HEIGHT
FALLS AND INCREASING CYCLONIC SHEAR VORTICITY ACROSS THE
MID-ATLANTIC. 15Z WV IMAGERY AND RAP DATA SUGGESTS THAT A SMALL
AMPLITUDE SHORTWAVE (OR AN MCV SPAWNED BY UPSTREAM CONVECTION
EARLIER THIS MORNING) IS PRESENT IN VICINITY OF THE CLT METRO AREA.
THIS FEATURE APPEARS TO BE ENHANCING CLOUD COVER ACROSS THE W/SW
PIEDMONT...AND A SLIGHT `SWIRL` IS EVEN DISCERNIBLE IN VIS SAT
IMAGERY. ENHANCED CLOUD COVER ASSOC/W THIS FEATURE IS ALREADY
CREATING A DIFF HEATING BOUNDARY ACROSS THE SW PIEDMONT AND
SANDHILLS...FURTHER COMPLICATING THE FORECAST. REGARDLESS...THIS
FEATURE COULD PROVIDE SUFFICIENT FORCING FOR CONVECTIVE DEVELOPMENT
BETWEEN 16-21Z IN THE SANDHILLS AND SE COASTAL PLAIN...ESPECIALLY
GIVEN MODERATE TO STRONG INSTABILITY AND LITTLE/NO CINH. AT THE SAME
TIME...SUBSIDENCE IN THE WAKE OF THIS FEATURE COULD SUPPRESS
CONVECTIVE DEVELOPMENT IN THE W/NW PIEDMONT THROUGH MID/LATE
AFTERNOON. GIVEN CYCLONIC FLOW ALOFT IT IS CERTAINLY POSSIBLE THAT
ADDITIONAL DISTURBANCES WILL PROGRESS ACROSS THE REGION LATER THIS
EVENING/TONIGHT...THOUGH SUCH FEATURES COULD ALSO RESULT IN
SUBSIDENCE /SUPPRESSED DEVELOPMENT/ DEPENDING ON THE TRACK...TIMING
AND LOCATION. WITH THE ABOVE IN MIND...WILL INDICATE PRECIP CHANCES
RANGING FROM 30-50%...LOWEST IN THE W/NW PIEDMONT AND HIGHEST IN THE
SANDHILLS/SE COASTAL PLAIN.
TEMPERATURES:
EXPECT HIGHS TODAY RANGING FROM THE MID/UPPER 80S IN THE WESTERN
PIEDMONT TO THE LOWER 90S IN THE COASTAL PLAIN...PRIMARILY DEPENDING
ON CLOUD COVER. LOWS TONIGHT SIMILAR TO LAST NIGHT IN THE LOWER 70S.
SEVERE THREAT:
THOUGH DEEP-LAYER SHEAR REMAINS WEAK (15-20 KT) AND SIMILAR TO
YESTERDAY...STEEPER MID-LEVEL LAPSE RATES (6.0-7.0 C/KM)...MODERATE
INSTABILITY...AND A DRIER MID-LEVEL AIRMASS/HIGHER DCAPE (750 TO
1250 J/KG) WOULD SUGGEST MORE ROBUST COLD POOLS AND A BETTER
POTENTIAL FOR DAMAGING WINDS WITH DEEP CONVECTION THIS AFT/EVE.
GIVEN ABOVE NORMAL UNCERTAINTY WITH REGARD TO CONVECTIVE COVERAGE...
THE THREAT WILL BE CONDITIONAL IN NATURE...ESPECIALLY ACROSS THE
N/NW PIEDMONT WHERE THE THERMODYNAMIC ENVIRONMENT WILL BE MORE
SUPPORTIVE BUT CONVECTIVE INITIATION WILL BE MORE QUESTIONABLE. WILL
MENTION A CHANCE OF ISOLD SVR STORMS IN THE HWO ALONG/EAST OF HWY 1
THIS AFT/EVE WHERE DEVELOPMENT APPEARS MORE LIKELY. -VINCENT
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 350 AM MONDAY...
AFOREMENTIONED UPPER LEVEL TROUGH WILL ADVANCE EASTWARD ACROSS THE
NORTHEAST AND NEW ENGLAND STATES ON TUESDAY WITH TRAILING SFC COLD
FRONT MOVING INTO THE AREA TUESDAY AFTERNOON AND OFFSHORE BY TUESDAY
EVENING. WELL REMOVED FROM THE SHORTWAVE TROUGH DYNAMICS AND JET
SUPPORT OVER SOUTHERN NEW ENGLAND COAST...MID AND UPPER LEVEL
SUPPORT OVER THE CAROLINAS WILL BE QUITE DIRE TUESDAY AFTERNOON.
ADDITIONALLY...WEAKENING LOW-LEVEL MOISTURE FLUX CONVERGENCE OWING
TO THE DEEP LAYER WESTERLY FLOW IN PLACE EAST OF THE MOUNTAINS WILL
RESULT IN ISOLATED TO SCATTERED SHOWERS AND STORMS TUESDAY
AFTERNOON...WITH BEST CHANCE AGAIN IN THE EAST DUE TO THE TIMING OF
THE FRONTAL PASSAGE COINCIDING WITH PEAK AFTERNOON HEATING AND
MODERATE DESTABILIZATION. GIVEN WEAK FORCING...SEVERE THREAT WILL
REMAIN LOW WITH ONLY AN ISOLATED STRONG TO SEVERE STORM EXPECTED...
MAINLY ACROSS THE FAR EAST TUESDAY AFTERNOON. HIGHS IN THE MID 80S
WEST TO NEAR 90 ACROSS THE SOUTHEAST.
WEAK HIGH PRESSURE WILL BUILD BEHIND THE FRONT WITH ENSUING N-NELY
WINDS ADVECTING DRIER AND COOLER AIR INTO THE AREA OVERNIGHT. LOWS
IN THE LOWER 60S NW TO UPPER 60S SE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 AM MONDAY...
OVERALL THE LONG TERM PERIOD WILL BE CHARACTERIZED BY DRIER
CONDITIONS AS THE WESTERLIES REMAIN WELL NORTH OF THE REGION AND
SURFACE HIGH PRESSURE AND WEAK FLOW ALOFT MOSTLY DOMINATES THE
WEATHER ACROSS CENTRAL NC. THE FRONT THAT IS PROGGED TO MOVE THROUGH
THE AREA ON TUESDAY WILL BE SOUTH OF THE FORECAST AREA BY WEDNESDAY
MORNING...WITH DRIER AIR FILTERING IN BEHIND THE FRONT AS HIGH
PRESSURE BUILDS IN FROM THE NORTHWEST. ANOTHER REINFORCING SHOT OF
STRONGER SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FRIDAY INTO
SATURDAY AS A SHORTWAVE IN THE WESTERLIES TO OUR NORTH DRAGS ANOTHER
FRONT THROUGH NEW ENGLAND/NORTHERN MID ATLANTIC REGION ON THURSDAY.
GIVEN THE DRIER AIR IN PLACE OVER OUR REGION...AM NOT EXPECTING ANY
PRECIP WITH THE ASSOCIATED WEAK TAIL END OF THE SURFACE TROUGH. THE
NEXT CHANCE OF PRECIP...ALTHOUGH ONLY MINIMAL CHANCES AT BEST...WILL
COME LATE IN THE WEEKEND AS THE SURFACE HIGH SHIFTS OFFSHORE AND
RETURN FLOW GRADUALLY BEGINS TO INCREASE OUR MOISTURE ONCE AGAIN.
TEMPS WILL GENERALLY BE NEAR TO SLIGHTLY BELOW NORMAL THROUGH THE
ENTIRE PERIOD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 1130 AM MONDAY...
24-HR TAF PERIOD:
AFTER LINGERING MVFR CEILINGS THIS MORNING LIFT TO VFR BY 16Z...
EXPECT VFR CONDITIONS TO GENERALLY PREVAIL THROUGH EARLY TO MID
AFTERNOON. ANTICIPATE AN INCREASING CHANCE FOR SHOWERS AND
THUNDERSTORMS AT ALL TERMINALS FROM MID/LATE AFTERNOON THROUGH THIS
EVENING...WITH THE RELATIVE BEST CHANCE AT THE RDU/FAY/RWI
TERMINALS. AN ISOLD SVR STORM WITH SFC WIND GUSTS AS HIGH AS 35-50
KT CANNOT BE RULED OUT. OTHERWISE...EXPECT A POTENTIAL FOR SUB-VFR
FOG OR CEILINGS ONCE AGAIN EARLY TUE MORNING (08-14Z).
LOOKING AHEAD:
A CHANCE OF SHOWERS/STORMS WILL PERSIST ON TUE AS A COLD FRONT
TRACKS SOUTHEAST ACROSS CENTRAL NC...WITH THE BEST CHANCE AT THE
EASTERN TERMINALS (RDU/FAY/RWI) DURING THE AFTERNOON AND EARLY
EVENING. ASIDE FROM A SMALL CHANCE FOR FOG AT THE FAY/RWI TERMINALS
AROUND SUNRISE (08-12Z) EACH MORNING...EXPECT VFR CONDITIONS WED-FRI
AS HIGH PRESSURE BUILDS INTO THE REGION. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
111 PM CDT MON SEP 2 2013
.UPDATE...
ISSUED AT 111 PM CDT MON SEP 2 2013
AS OF 18 UTC...SURFACE HIGH PRESSURE CONTINUES TO PROPAGATE INTO
MINNESOTA...WITH RETURN FLOW ACROSS WESTERN AND CENTRAL NORTH
DAKOTA. NO CHANGES REQUIRED WITH THIS FORECAST UPDATE...OTHER THAN
TO BLEND TO THE OBSERVED TRENDS.
UPDATE ISSUED AT 1014 AM CDT MON SEP 2 2013
NO SIGNIFICANT CHANGES WITH THIS UPDATE AS THE INHERITED FORECAST
IS ON TRACK...WITH ALL FOG BURNED OFF ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.
UPDATE ISSUED AT 645 AM CDT MON SEP 2 2013
PATCHY FOG HAS DEVELOPED FROM PARTS OF THE JAMES RIVER VALLEY
NORTH AND WEST TOWARDS THE TIOGA AREA. THE HRRR SHOWED THIS TO
SOME DEGREE...AND HAVE ADDED A MENTION OF PATCHY FOG IN THE GRIDS
TO COVER THE LOWER VISIBILITIES. WILL CARRY THE FOG THROUGH 14Z
WHICH IS CLOSE TO THE TIMING FROM THE HRRR. MADE SMALL ADJUSTMENTS
TO TEMPERATURES AND DEWPOINTS TO REFLECT CURRENT
CONDITIONS...OTHERWISE THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT MON SEP 2 2013
TRANQUIL WEATHER WILL HIGHLIGHT THE SHORT TERM FORECAST.
CURRENTLY...SURFACE HIGH PRESSURE CENTER WAS NEAR THE BORDER OF
NORTH DAKOTA/MINNESOTA/MANITOBA WITH THE HIGH AXIS EXTENDING
SOUTHWARD ACROSS THE RED RIVER VALLEY. BROAD LOW PRESSURE WAS OVER
THE LEE OF THE ROCKIES. CLEAR SKIES AND LIGHT WINDS NEAR THE SURFACE
HIGH CENTER HAS ALLOWED TEMPERATURES TO DROP INTO THE 40S OVER MUCH
OF EASTERN AND CENTRAL NORTH DAKOTA. MOST OF THE WESTERN THIRD OF
THE STATE REMAINED IN THE 50S AS OF 3 AM CDT.
SOME OF THE SHORT TERM MODELS HINTED AT LIGHT TO MODERATE FOG...OR
LOW CLOUDS...FROM NEAR BISMARCK TO WILLISTON/MINOT. ALTHOUGH
SATELLITE PICS INDICATE CLEAR SKIES...MANDAN AIRPORT WAS REPORTING
CLOUDS AT 4300 FEET. THINKING THIS IS MORE ISOLATED IN NATURE AND
WILL KEEP CLEAR SKIES IN THE FORECAST TODAY AND TONIGHT.
THE SURFACE HIGH IS FORECAST TO MOVE SOUTHEAST INTO MINNESOTA THIS
EVENING AND TO WISCONSIN/IOWA BY DAYBREAK TUESDAY MORNING. THUS
SOUTH/SOUTHEAST WINDS AT 5 TO 15 MPH SHOULD PREVAIL TODAY. AFTER
YESTERDAY`S HIGHS FROM THE UPPER 60S TO UPPER 70S/NEAR
80...TEMPERATURES SHOULD BE A TAD WARMER TODAY WITH THE COOL HIGH
PRESSURE EXITING THE AREA. LOOKING AT HIGHS FROM THE MID 70S IN THE
TURTLE MOUNTAINS TO JAMES RIVER BASIN...TO THE UPPER 80S IN THE FAR
WEST.
IN ADDITION...LOW TEMPERATURES MONDAY NIGHT WILL ALSO BE HIGHER THAN
REPORTED THIS MORNING...WITH SOUTH WINDS OF AROUND 5 TO 10 MPH
TONIGHT. LOOKING AT LOWS FROM THE LOWER 50S EASTERN PORTIONS OF
CENTRAL NORTH DAKOTA TO THE LOWER 60S WEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 315 AM CDT MON SEP 2 2013
THE LONG TERM WILL BEGIN WITH A LARGE RIDGE ACROSS THE
CENTRAL UNITED STATES. THE 02.00 NAM AND GFS BOTH BRING A WAVE
THROUGH THE H5 RIDGE ON TUESDAY AND MOVE IT ACROSS WESTERN AND
SOUTHERN NORTH DAKOTA TUESDAY INTO TUESDAY NIGHT. WILL CARRY THE
HIGHEST POPS ACROSS THE SOUTHWEST AND SOUTH...WITH LESSER CHANCES IN
THE NORTH.
THE H5 RIDGE AMPLIFIES AND DOMINATES THE WEATHER OVER THE NORTHERN
PLAINS FROM WEDNESDAY THROUGH THURSDAY NIGHT. THIS WILL BRING
MAINLY DRY WEATHER ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE
RIDGE BREAKS DOWN TOWARDS THE WEEKEND AS AN UPPER LOW APPROACHES
THE NORTHERN PLAINS FROM THE PACIFIC NORTHWEST. THE CHANCES FOR
RAIN / THUNDERSTORMS WILL INCREASE AS THE UPPER LOW APPROACHES...AND
THE LATEST ALL BLEND MODEL CONSENSUS CAPTURES THIS TREND WELL.
TEMPERATURES WILL ALSO COOL AS THE RIDGE BREAKS DOWN AND THE RAIN
CHANCES INCREASE. WILL SEE HIGHS IN THE MID 80S TO LOWER 90S ON
THURSDAY AND FRIDAY...COOL INTO THE MID 70S TO MID 80S BY SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 111 PM CDT MON SEP 2 2013
VFR CONDITIONS ARE EXPECTED FOR THE 18 UTC TAFS WITH SURFACE HIGH
PRESSURE ACROSS MINNESOTA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JV
LONG TERM...CK
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1014 AM CDT MON SEP 2 2013
.UPDATE...
ISSUED AT 1014 AM CDT MON SEP 2 2013
NO SIGNIFICANT CHANGES WITH THIS UPDATE AS THE INHERITED FORECAST
IS ON TRACK...WITH ALL FOG BURNED OFF ACROSS WESTERN AND CENTRAL
NORTH DAKOTA.
UPDATE ISSUED AT 645 AM CDT MON SEP 2 2013
PATCHY FOG HAS DEVELOPED FROM PARTS OF THE JAMES RIVER VALLEY
NORTH AND WEST TOWARDS THE TIOGA AREA. THE HRRR SHOWED THIS TO
SOME DEGREE...AND HAVE ADDED A MENTION OF PATCHY FOG IN THE GRIDS
TO COVER THE LOWER VISIBILITIES. WILL CARRY THE FOG THROUGH 14Z
WHICH IS CLOSE TO THE TIMING FROM THE HRRR. MADE SMALL ADJUSTMENTS
TO TEMPERATURES AND DEWPOINTS TO REFLECT CURRENT
CONDITIONS...OTHERWISE THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT MON SEP 2 2013
TRANQUIL WEATHER WILL HIGHLIGHT THE SHORT TERM FORECAST.
CURRENTLY...SURFACE HIGH PRESSURE CENTER WAS NEAR THE BORDER OF
NORTH DAKOTA/MINNESOTA/MANITOBA WITH THE HIGH AXIS EXTENDING
SOUTHWARD ACROSS THE RED RIVER VALLEY. BROAD LOW PRESSURE WAS OVER
THE LEE OF THE ROCKIES. CLEAR SKIES AND LIGHT WINDS NEAR THE SURFACE
HIGH CENTER HAS ALLOWED TEMPERATURES TO DROP INTO THE 40S OVER MUCH
OF EASTERN AND CENTRAL NORTH DAKOTA. MOST OF THE WESTERN THIRD OF
THE STATE REMAINED IN THE 50S AS OF 3 AM CDT.
SOME OF THE SHORT TERM MODELS HINTED AT LIGHT TO MODERATE FOG...OR
LOW CLOUDS...FROM NEAR BISMARCK TO WILLISTON/MINOT. ALTHOUGH
SATELLITE PICS INDICATE CLEAR SKIES...MANDAN AIRPORT WAS REPORTING
CLOUDS AT 4300 FEET. THINKING THIS IS MORE ISOLATED IN NATURE AND
WILL KEEP CLEAR SKIES IN THE FORECAST TODAY AND TONIGHT.
THE SURFACE HIGH IS FORECAST TO MOVE SOUTHEAST INTO MINNESOTA THIS
EVENING AND TO WISCONSIN/IOWA BY DAYBREAK TUESDAY MORNING. THUS
SOUTH/SOUTHEAST WINDS AT 5 TO 15 MPH SHOULD PREVAIL TODAY. AFTER
YESTERDAY`S HIGHS FROM THE UPPER 60S TO UPPER 70S/NEAR
80...TEMPERATURES SHOULD BE A TAD WARMER TODAY WITH THE COOL HIGH
PRESSURE EXITING THE AREA. LOOKING AT HIGHS FROM THE MID 70S IN THE
TURTLE MOUNTAINS TO JAMES RIVER BASIN...TO THE UPPER 80S IN THE FAR
WEST.
IN ADDITION...LOW TEMPERATURES MONDAY NIGHT WILL ALSO BE HIGHER THAN
REPORTED THIS MORNING...WITH SOUTH WINDS OF AROUND 5 TO 10 MPH
TONIGHT. LOOKING AT LOWS FROM THE LOWER 50S EASTERN PORTIONS OF
CENTRAL NORTH DAKOTA TO THE LOWER 60S WEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 315 AM CDT MON SEP 2 2013
THE LONG TERM WILL BEGIN WITH A LARGE RIDGE ACROSS THE
CENTRAL UNITED STATES. THE 02.00 NAM AND GFS BOTH BRING A WAVE
THROUGH THE H5 RIDGE ON TUESDAY AND MOVE IT ACROSS WESTERN AND
SOUTHERN NORTH DAKOTA TUESDAY INTO TUESDAY NIGHT. WILL CARRY THE
HIGHEST POPS ACROSS THE SOUTHWEST AND SOUTH...WITH LESSER CHANCES IN
THE NORTH.
THE H5 RIDGE AMPLIFIES AND DOMINATES THE WEATHER OVER THE NORTHERN
PLAINS FROM WEDNESDAY THROUGH THURSDAY NIGHT. THIS WILL BRING
MAINLY DRY WEATHER ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE
RIDGE BREAKS DOWN TOWARDS THE WEEKEND AS AN UPPER LOW APPROACHES
THE NORTHERN PLAINS FROM THE PACIFIC NORTHWEST. THE CHANCES FOR
RAIN / THUNDERSTORMS WILL INCREASE AS THE UPPER LOW APPROACHES...AND
THE LATEST ALL BLEND MODEL CONSENSUS CAPTURES THIS TREND WELL.
TEMPERATURES WILL ALSO COOL AS THE RIDGE BREAKS DOWN AND THE RAIN
CHANCES INCREASE. WILL SEE HIGHS IN THE MID 80S TO LOWER 90S ON
THURSDAY AND FRIDAY...COOL INTO THE MID 70S TO MID 80S BY SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY )
ISSUED AT 1014 AM CDT MON SEP 2 2013
VFR CONDITIONS ARE EXPECTED FOR THE UPCOMING 18 UTC TAFS WITH
SURFACE HIGH PRESSURE ACROSS EASTERN NORTH DAKOTA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JV
LONG TERM...CK
AVIATION...AYD
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
702 AM CDT MON SEP 2 2013
.UPDATE...
ISSUED AT 702 AM CDT MON SEP 2 2013
12 UTC IR SATELLITE SHOWS WESTERN FLANK OF LOW CLOUDS ALONG A
WASKISH TO FOSSTON TO DETROIT LAKES TO ALEXANDRIA LINE. AS A
RESULT...UPDATED SKY COVER TO REFLECT SLOWER MOVEMENT AND
DISSIPATION. LATEST HRRR SUGGESTS THESE CLOUDS SHOULD BEGIN TO
BREAK-UP BY LATE MORNING/EARLY AFTERNOON WITH SUNNY SKIES BY MID-
LATE AFTERNOON. REST OF THE FORECAST IN GOOD SHAPE WITH NO CHANGES
NEEDED AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 345 AM CDT MON SEP 2 2013
MAIN ISSUE WILL BE TEMPERATURES WITH NO PRECIPITATION EXPECTED
THROUGH THE PERIOD. MODELS ARE IN GOOD AGREEMENT AND WILL USE A
BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
FOR TODAY...SURFACE HIGH PRESSURE WILL DOMINATE THE REGIONAL
WEATHER PATTERN. A VERY DRY AIR MASS WITH AFTERNOON CONVECTIVE
TEMPERATURES ABOVE 100 DEGREES WILL RESULT IN A CLOUDLESS DAY. THE
EXCEPTION BEING ACROSS THE FAR EASTERN FORECAST AREA WHERE THE
WESTERN FLANK OF A LOW CLOUD DECK WILL MOVE SLOWLY SOUTH AND WEST
THIS MORNING BEFORE DISSIPATING LATER THIS AFTERNOON. TEMPERATURES
TODAY WILL 5 TO 10 DEGREES WARMER THAN YESTERDAY WITH HIGHS IN THE
LOW TO MID 70S. SOUTHERLY RETURN FLOW WILL DEVELOP OVERNIGHT AS
THE SURFACE HIGH MOVES INTO WI. THIS...COMBINED WITH MODEST WARM
AIR ADVECTION WILL KEEP TEMPERATURES FROM BOTTOMING OUT AND EXPECT
TUESDAY MORNING LOWS FROM THE MID 40S TO MID 50S.
BOUNDARY LAYER TEMPERATURES RISE 5 TO 8 C BY TUESDAY AFTERNOON AS
A +18 TO +22 C 850 THERMAL RIDGE MOVES ACROSS THE FORECAST AREA.
AS A RESULT...AFTERNOON HIGHS WILL CLIMB INTO THE MID 80S. SOME
HIGH CLOUDS ARE POSSIBLE...BUT STILL EXPECT PLENTY OF SOLAR.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 AM CDT MON SEP 2 2013
TUESDAY NIGHT INTO EARLY WEDNESDAY...A DRY COLD FRONT WILL DROP
SOUTH FROM CANADA. DO NOT ANTICIPATE ANY PRECIPITATION WITH HIGHER
MOISTURE CONFINED ABOVE 700 HPA. PRIMARY SENSIBLE WEATHER IMPACTS
WILL BE A WIND SHIFT TO THE NORTH-NORTHEAST AND DECREASING
TEMPERATURES. HIGHS WEDNESDAY WILL RANGE FROM THE LOWS 70S ALONG
THE INTERNATIONAL BORDER TO THE LOW 80S ACROSS THE SOUTHERN
VALLEY.
FOR THU THROUGH SUN NIGHT...EXPECT DRY AND WARM CONDITIONS THROUGH
SAT...WITH TEMPS WELL ABOVE NORMAL AND UPPER RIDGING OVER THE AREA.
MODELS ARE IN GOOD AGREEMENT WITH A POTENT SHORTWAVE MOVING INTO
WESTERN ND SUNDAY...AND THIS WILL BRING THE NEXT CHANCE FOR SHOWERS
AND STORMS INTO THE REGION. INSTABILITY AND MOISTURE WILL ALSO
INCREASE AHEAD OF THE SHORTWAVE...WITH PWATS LIKELY AROUND 1.5
INCHES. THEREFORE...THIS COULD BE A MORE WIDESPREAD PRECIP EVENT AND
COULD LAST INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 702 AM CDT MON SEP 2 2013
MVFR CEILINGS AT KBJI EXPECTED TO DISSIPATE SOMETIME BETWEEN 14
AND 16 UTC. ALL OTHER TAF SITES WILL BE VFR THROUGH 12 UTC TUESDAY
WITH SUNNY/CLEAR SKIES AND LIGHT WIND.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/DK
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
646 AM CDT MON SEP 2 2013
.UPDATE...
ISSUED AT 645 AM CDT MON SEP 2 2013
PATCHY FOG HAS DEVELOPED FROM PARTS OF THE JAMES RIVER VALLEY
NORTH AND WEST TOWARDS THE TIOGA AREA. THE HRRR SHOWED THIS TO
SOME DEGREE...AND HAVE ADDED A MENTION OF PATCHY FOG IN THE GRIDS
TO COVER THE LOWER VISIBILITIES. WILL CARRY THE FOG THROUGH 14Z
WHICH IS CLOSE TO THE TIMING FROM THE HRRR. MADE SMALL ADJUSTMENTS
TO TEMPERATURES AND DEWPOINTS TO REFLECT CURRENT
CONDITIONS...OTHERWISE THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT MON SEP 2 2013
TRANQUIL WEATHER WILL HIGHLIGHT THE SHORT TERM FORECAST.
CURRENTLY...SURFACE HIGH PRESSURE CENTER WAS NEAR THE BORDER OF
NORTH DAKOTA/MINNESOTA/MANITOBA WITH THE HIGH AXIS EXTENDING
SOUTHWARD ACROSS THE RED RIVER VALLEY. BROAD LOW PRESSURE WAS OVER
THE LEE OF THE ROCKIES. CLEAR SKIES AND LIGHT WINDS NEAR THE SURFACE
HIGH CENTER HAS ALLOWED TEMPERATURES TO DROP INTO THE 40S OVER MUCH
OF EASTERN AND CENTRAL NORTH DAKOTA. MOST OF THE WESTERN THIRD OF
THE STATE REMAINED IN THE 50S AS OF 3 AM CDT.
SOME OF THE SHORT TERM MODELS HINTED AT LIGHT TO MODERATE FOG...OR
LOW CLOUDS...FROM NEAR BISMARCK TO WILLISTON/MINOT. ALTHOUGH
SATELLITE PICS INDICATE CLEAR SKIES...MANDAN AIRPORT WAS REPORTING
CLOUDS AT 4300 FEET. THINKING THIS IS MORE ISOLATED IN NATURE AND
WILL KEEP CLEAR SKIES IN THE FORECAST TODAY AND TONIGHT.
THE SURFACE HIGH IS FORECAST TO MOVE SOUTHEAST INTO MINNESOTA THIS
EVENING AND TO WISCONSIN/IOWA BY DAYBREAK TUESDAY MORNING. THUS
SOUTH/SOUTHEAST WINDS AT 5 TO 15 MPH SHOULD PREVAIL TODAY. AFTER
YESTERDAY`S HIGHS FROM THE UPPER 60S TO UPPER 70S/NEAR
80...TEMPERATURES SHOULD BE A TAD WARMER TODAY WITH THE COOL HIGH
PRESSURE EXITING THE AREA. LOOKING AT HIGHS FROM THE MID 70S IN THE
TURTLE MOUNTAINS TO JAMES RIVER BASIN...TO THE UPPER 80S IN THE FAR
WEST.
IN ADDITION...LOW TEMPERATURES MONDAY NIGHT WILL ALSO BE HIGHER THAN
REPORTED THIS MORNING...WITH SOUTH WINDS OF AROUND 5 TO 10 MPH
TONIGHT. LOOKING AT LOWS FROM THE LOWER 50S EASTERN PORTIONS OF
CENTRAL NORTH DAKOTA TO THE LOWER 60S WEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 315 AM CDT MON SEP 2 2013
THE LONG TERM WILL BEGIN WITH A LARGE RIDGE ACROSS THE
CENTRAL UNITED STATES. THE 02.00 NAM AND GFS BOTH BRING A WAVE
THROUGH THE H5 RIDGE ON TUESDAY AND MOVE IT ACROSS WESTERN AND
SOUTHERN NORTH DAKOTA TUESDAY INTO TUESDAY NIGHT. WILL CARRY THE
HIGHEST POPS ACROSS THE SOUTHWEST AND SOUTH...WITH LESSER CHANCES IN
THE NORTH.
THE H5 RIDGE AMPLIFIES AND DOMINATES THE WEATHER OVER THE NORTHERN
PLAINS FROM WEDNESDAY THROUGH THURSDAY NIGHT. THIS WILL BRING
MAINLY DRY WEATHER ACROSS WESTERN AND CENTRAL NORTH DAKOTA. THE
RIDGE BREAKS DOWN TOWARDS THE WEEKEND AS AN UPPER LOW APPROACHES
THE NORTHERN PLAINS FROM THE PACIFIC NORTHWEST. THE CHANCES FOR
RAIN / THUNDERSTORMS WILL INCREASE AS THE UPPER LOW APPROACHES...AND
THE LATEST ALL BLEND MODEL CONSENSUS CAPTURES THIS TREND WELL.
TEMPERATURES WILL ALSO COOL AS THE RIDGE BREAKS DOWN AND THE RAIN
CHANCES INCREASE. WILL SEE HIGHS IN THE MID 80S TO LOWER 90S ON
THURSDAY AND FRIDAY...COOL INTO THE MID 70S TO MID 80S BY SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM CDT MON SEP 2 2013
SURFACE HIGH PRESSURE WAS OVER THE RED RIVER VALLEY WITH BROAD LOW
PRESSURE IN THE LEE OF THE ROCKIES. VARIABLE CLOUDS AND VSBYS
REPORTED AT A FEW ISOLATED LOCALES. LIGHT WINDS AT KJMS AND LATEST
OBS SHOWED LOCALIZED FOG FORMING IN THE KJMS AREA...WITH VSBYS
RANGING FROM 1/4 MILE TO 3 MILES AND A CEILING OF 100 FEET
REPORTED. OTHER SITES REPORTING FOG INCLUDE TIOGA (BETWEEN KISN
AND KMOT) WITH 1/4 MILE VSBY. DIFFICULT TO PICK OUT ANY TREND FROM
SATELLITE PICS AS THE LOW CLOUDS/FOG ARE NOT SHOWING UP (YET).
THUS WILL PUT A TEMPO GROUP IN WITH LOWER CIGS.
SURFACE HIGH SHOULD MOVE SOUTHEAST TODAY AND TONIGHT. SOUTHERLY
SURFACE WINDS SHOULD INCREASE TO 10 TO 15 MPH TODAY...MAINLY AFT
15Z-17Z...AND EXPECT VFR FOR ALL TAF SITES AFT 14-15Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...JV
LONG TERM...CK
AVIATION...JV
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
141 AM EDT MON SEP 2 2013
.SYNOPSIS...
MUGGY ENVIRONMENT LINGERS INTO MONDAY EVENING. COLD FRONT MONDAY
NIGHT. COOLER AND DRIER AIRMASS TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
130 AM UPDATE...DRIED OUT POPS FOR MUCH OF THE MORNING.
OTHERWISE...MADE NO MAJOR CHANGES TO THE FORECAST.
PREVIOUS DISCUSSION FOLLOWS...
AFTERNOON DISTURBANCE EXITING SOUTHERN MOUNTAINS AND GREENBRIER
VALLEY NOW. WAS FASTER LOWERING POPS DOWN THIS EVENING. ALSO
FASTER FORMING SOME VALLEY FOG IN THE SOUTHERN COAL FIELDS AND
GREENBRIER VALLEY IN WAKE OF THE LATE AFTERNOON SHOWERS.
DESPITE THE LACK OF CONVECTION AND CLOUDS OVER OUR WESTERN
LOWLANDS...STILL THINK A LATE NIGHT OR MORNING SHOWER OR
THUNDERSTORM COULD REFORM OVERNIGHT. SO ONLY REMOVAL OF POPS WAS
EARLY THIS EVENING BEFORE INCREASING BACK INTO THE 20 TO 30 PERCENT
RANGE FOR ANY ONE SPOT. RAP INDICATES A WEAK MID LEVEL DISTURBANCE
PASSING SE OHIO AROUND 03Z TO 05Z AND IN WV AFTER 05Z.
THIS PLAYS HAVOC WITH FIGURING OUT THE FOG COVERAGE FOR THE PREDAWN.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
COLD FRONT FINALLY DEPARTS MONDAY NIGHT WITH HIGH PRESSURE BUILDING
IN BEHIND THE SYSTEM. VERY DRY AIR TO ADVECT IN BEHIND THE FRONT FOR
TUESDAY...ALTHOUGH MAY START OUT WITH SOME LOW LEVEL STRATUS IN
PLACE AS NAM BUFR SOUNDINGS SUGGEST SATURATION BELOW 875MB AND
NORTHERLY FLOW AT 925MB. LOW STRATUS DECK SHOULD LIFT AND DISSOLVE
BY LATE MORNING TUESDAY AND BE REPLACED IN THE AFTERNOON BY DIURNAL
CUMULUS AS A RESULT OF BOUNDARY LAYER MIXING. WILL BE COMPLETELY
DEVOID OF ANY MOISTURE ALL THE WAY THROUGH WEDNESDAY...LESS SOME
PATCHY THIN CIRRUS DRIFTING THROUGH ON WEDNESDAY AFTERNOON.
WITH A NEW AIRMASS IN PLACE...CAN EXPECT MORE TYPICAL LATE SUMMER
CONDITIONS IN TERMS OF TEMPERATURES AND DEWPOINTS AT THE SURFACE.
DRIER AIR AND INSOLATION WILL ALLOW TEMPERATURES TO DROP INTO THE
50S TUESDAY NIGHT...WITH SOME ISOLATED 40S IN THE LOWLANDS...AND
MORE PREVALENT IN THE MOUNTAINS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
EXTENDED FORECAST REMAINS PRIMARILY DRY. HIGH PRESSURE IN CONTROL
INTO THE EARLY PART OF THE WEEKEND...BUT MAY GET THE TAIL END OF A
COLD FRONT FOR THE END OF THE WEEK. THIS WOULD HAVE LITTLE AFFECT ON
THE MIDDLE OHIO VALLEY AND CENTRAL APPALACHIANS OTHER THAN A LITTLE
CLOUD COVER. LONG RANGE MODELS DEVELOP A SURFACE LOW IN THE CENTRAL
PLAINS FOR THE END OF THE WEEKEND WITH A WARM FRONT TO OUR NORTH. IN
THE END...HEIGHTS MAKE A RECOVERY FROM THE MILDER AIRMASS AT THE
BEGINNING OF THE LONG TERM FORECAST...AND WILL PUSH TO SLIGHTLY
ABOVE NORMAL TEMPERATURES AGAIN BY DAY 7.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MVFR/IFR VALLEY FOG EXPECTED THROUGH 13Z...BEFORE LIFTING TO VFR
AREA WIDE. COLD FRONT WILL APPROACH DURING THE DAY MONDAY...AND
MOVE EAST ACROSS THE AREA MONDAY NIGHT. EXPECT SCATTERED SHOWERS
AND THUNDERSTORMS TO DEVELOP...MAINLY AFTER 14Z...WITH BRIEF
MVFR/IFR CONDITIONS AND GUSTY WINDS IN VICINITY OF STORMS.
AFTER 04Z...BULK OF CONVECTION SHOULD HAVE DIED
DOWN...PARTICULARLY ACROSS SOUTHEAST OHIO...EASTERN KENTUCKY...AND
ADJACENT WV AREAS. BEHIND THE FRONT...PARTIAL CLEARING ACROSS THE
NORTH/WEST...WILL RESULT IN THE FORMATION OF IFR/LIFR FOG...WITH
FOG OR LOW STRATUS GENERALLY ALONG/EAST OF A LINE FROM CRW TO CKB.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z
TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: FOG DEVELOPMENT AND DENSITY 06Z TO 12Z MONDAY
TOUGH TO FIGURE DUE TO CLOUD COVER AND CHANCE OF CONVECTION
REFORMING. DEVELOPMENT OF FOG AND OR STRATUS AFTER 00Z TUESDAY MAY
VARY FROM FORECAST.
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 MON 09/02/13
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 L L L L L L H H H H H M
HTS CONSISTENCY H M M M L L H H H H H M
BKW CONSISTENCY L L L L L H H H M M M M
EKN CONSISTENCY L L L L L L L L H M M M
PKB CONSISTENCY H H H H L L M H H H H M
CKB CONSISTENCY H M M H L L H H H H H H
AFTER 06Z TUESDAY...
LINGERING CONVECTION NEAR COLD FRONT MONDAY EVENING MAY CAUSE IFR
CONDITIONS. IFR FOG POSSIBLE TUESDAY AND WEDNESDAY MORNINGS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/26
NEAR TERM...KTB/SL
SHORT TERM...26
LONG TERM...26
AVIATION...SL
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
745 PM MDT TUE SEP 3 2013
.UPDATE...
ISSUED AT 742 PM MDT TUE SEP 3 2013
00Z KUNR SOUNDING SHOWS MLCIN. LATEST CONVECTIVE ALLOWING MODELS
SHOW LITTLE IN THE WAY OF SHRA/TSRA OVERNIGHT. UPSTREAM WAVES OVER
WESTERN WY WILL HAVE LITTLE MUCAPE TO WORK WITH OVERNIGHT. DIURNAL
LESSENING OF INSTABILITY NOTED ON MESOANALYSIS PRODUCTS. WILL
REDUCE POPS WITH UPDATE FOR ENTIRE CWA AND LEAVE A SMALL ARC OF 15
POPS FROM SOUTHEAST MT INTO SOUTH CENTRAL SD.
&&
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 234 PM MDT TUE SEP 3 2013
WATER VAPOR IMAGERY HAS THE UPPER RIDGE BUILDING FROM THE ROCKIES
INTO THE PLAINS. SEVERAL SHORTWAVES ARE MOVING THROUGH THE RIDGE
WITH ONE OVER CENTRAL SOUTH DAKOTA...TWO SMALL WAVES IN WESTERN AND
CENTRAL WYOMING...AND A LARGER WAVE NEAR SALT LAKE CITY. RADAR HAS
CONVECTION EXTENDING THROUGH CENTRAL SOUTH DAKOTA...WITH NOT MUCH
HAPPENING OVER WYOMING WITH THE SMALLER WAVES. VISIBLE SATELLITE IS
SHOWING SOME CU DEVELOPING OVER THE BLACK HILLS...PARTS OF
NORTHEASTERN WYOMING AND SOUTHWEST SOUTH DAKOTA. AT THE SURFACE...AN
AREA OF LOW PRESSURE IS LOCATED OVER SOUTHWESTERN SOUTH DAKOTA WITH
A WARM FRONT EXTENDING THROUGH SOUTH CENTRAL SOUTH DAKOTA AND A LEE
TROF THROUGH THE BLACK HILLS AND EASTERN MONTANA.
FOR TONIGHT...NOT CONFIDENT IN THE PLACEMENT OF CONVECTION WITH THE
HRRR AND RAP MODELS SHOWING LITTLE IF ANY CONVECTION AND LESS MLCAPE
THAN THE NAM OR GFS. EXPECT SOME CONVECTION WILL FIRE DUE TO DIURNAL
HEATING...HOWEVER SHEAR IS NOT OVERLY IMPRESSIVE FOR SEVERE
POTENTIAL. MAIN CONCERN WITH ANY STORM THAT DEVELOPS TONIGHT WILL BE
HEAVY RAIN POTENTIAL. PWS ARE 200 PERCENT OF NORMAL WITH STORM
MOVEMENT AROUND 15KTS. HOWEVER WITH MY LACK OF CONFIDENCE ON STORM
DEVELOPMENT AND PLACEMENT HAVE DECIDED TO FORGO ANY TYPE OF HYDRO
HEADLINES AT THIS TIME.
ON WEDNESDAY/WEDNESDAY NIGHT...UPPER RIDGE SHOULD AMPLIFY FURTHER
INTO THE NORTHERN PLAINS. HOWEVER...TEMPS WILL BE FEW DEGREES COOLER
AS SURFACE LOW SHIFTS INTO EASTERN COLORADO AND PULLS IN SLIGHTLY
COOLER AIR FROM THE NORTH. BEST CHANCE FOR ANY CONVECTION WILL BE
ACROSS THE FAR WESTERN ZONES NEAR THE INVERTED TROF EXTENDING NORTH
FROM THE SURFACE LOW OVER EASTERN COLORADO AND POSSIBLY IN SOUTH
CENTRAL SOUTH DAKOTA WITH THE WARM FRONT EXTENDING THROUGH NORTHERN
NEBRASKA.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 234 PM MDT TUE SEP 3 2013
LONG WAVE RIDGE OVER CWA WITH A LONG WAVE TROF OVER THE LOWER GREAT
LAKES AND JUST OFF THE WEST COAST. GFS AND ECMWF SHOW PROGRESSION
OF STRONG SHORT WAVE OUT OF THE WEST COAST TROF TO ERN MT BY 12Z
MON AS LONG WAVE RIDGE UNDERGOES FLATTENING AND DISCONTINUOUS
RETROGRESSION TO 135W BY 12Z MON. RIDGE THEN AMPLIFIES AND MOVES
SLOWLY E WARD DURING MID WEEK.
THIS EVOLUTION ALLOWS SIGNIFICANT SURGE OF COOLER AIR FOLLOWING E
WARD MOVEMENT OF SHORT WAVE TROF AND A RETURN TO MORE SEASONAL
TEMPERATURES TUES. THE COLD FRONT AND UPPER SUPPORT LEADING THIS
SURGE WILL LIKELY RESULT IN SHOWERS AND TSTMS REFLECTED IN HIGHER
POPS SATURDAY INTO MONDAY.
STAYED QUITE CLOSE TO GUIDANCE WITH TEMPERATURES THROUGH THE
EXTENDED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 520 PM MDT TUE SEP 3 2013
ISOLATED SHRA/TSRA ARE POSSIBLE MAINLY ON THE SD PLAINS TONIGHT. OTHERWISE
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...MLS
LONG TERM...BARBER
AVIATION...HELGESON
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
521 PM MDT TUE SEP 3 2013
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 234 PM MDT TUE SEP 3 2013
WATER VAPOR IMAGERY HAS THE UPPER RIDGE BUILDING FROM THE ROCKIES
INTO THE PLAINS. SEVERAL SHORTWAVES ARE MOVING THROUGH THE RIDGE
WITH ONE OVER CENTRAL SOUTH DAKOTA...TWO SMALL WAVES IN WESTERN AND
CENTRAL WYOMING...AND A LARGER WAVE NEAR SALT LAKE CITY. RADAR HAS
CONVECTION EXTENDING THROUGH CENTRAL SOUTH DAKOTA...WITH NOT MUCH
HAPPENING OVER WYOMING WITH THE SMALLER WAVES. VISIBLE SATELLITE IS
SHOWING SOME CU DEVELOPING OVER THE BLACK HILLS...PARTS OF
NORTHEASTERN WYOMING AND SOUTHWEST SOUTH DAKOTA. AT THE SURFACE...AN
AREA OF LOW PRESSURE IS LOCATED OVER SOUTHWESTERN SOUTH DAKOTA WITH
A WARM FRONT EXTENDING THROUGH SOUTH CENTRAL SOUTH DAKOTA AND A LEE
TROF THROUGH THE BLACK HILLS AND EASTERN MONTANA.
FOR TONIGHT...NOT CONFIDENT IN THE PLACEMENT OF CONVECTION WITH THE
HRRR AND RAP MODELS SHOWING LITTLE IF ANY CONVECTION AND LESS MLCAPE
THAN THE NAM OR GFS. EXPECT SOME CONVECTION WILL FIRE DUE TO DIURNAL
HEATING...HOWEVER SHEAR IS NOT OVERLY IMPRESSIVE FOR SEVERE
POTENTIAL. MAIN CONCERN WITH ANY STORM THAT DEVELOPS TONIGHT WILL BE
HEAVY RAIN POTENTIAL. PWS ARE 200 PERCENT OF NORMAL WITH STORM
MOVEMENT AROUND 15KTS. HOWEVER WITH MY LACK OF CONFIDENCE ON STORM
DEVELOPMENT AND PLACEMENT HAVE DECIDED TO FORGO ANY TYPE OF HYDRO
HEADLINES AT THIS TIME.
ON WEDNESDAY/WEDNESDAY NIGHT...UPPER RIDGE SHOULD AMPLIFY FURTHER
INTO THE NORTHERN PLAINS. HOWEVER...TEMPS WILL BE FEW DEGREES COOLER
AS SURFACE LOW SHIFTS INTO EASTERN COLORADO AND PULLS IN SLIGHTLY
COOLER AIR FROM THE NORTH. BEST CHANCE FOR ANY CONVECTION WILL BE
ACROSS THE FAR WESTERN ZONES NEAR THE INVERTED TROF EXTENDING NORTH
FROM THE SURFACE LOW OVER EASTERN COLORADO AND POSSIBLY IN SOUTH
CENTRAL SOUTH DAKOTA WITH THE WARM FRONT EXTENDING THROUGH NORTHERN
NEBRASKA.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 234 PM MDT TUE SEP 3 2013
LONG WAVE RIDGE OVER CWA WITH A LONG WAVE TROF OVER THE LOWER GREAT
LAKES AND JUST OFF THE WEST COAST. GFS AND ECMWF SHOW PROGRESSION
OF STRONG SHORT WAVE OUT OF THE WEST COAST TROF TO ERN MT BY 12Z
MON AS LONG WAVE RIDGE UNDERGOES FLATTENING AND DISCONTINUOUS
RETROGRESSION TO 135W BY 12Z MON. RIDGE THEN AMPLIFIES AND MOVES
SLOWLY E WARD DURING MID WEEK.
THIS EVOLUTION ALLOWS SIGNIFICANT SURGE OF COOLER AIR FOLLOWING E
WARD MOVEMENT OF SHORT WAVE TROF AND A RETURN TO MORE SEASONAL
TEMPERATURES TUES. THE COLD FRONT AND UPPER SUPPORT LEADING THIS
SURGE WILL LIKELY RESULT IN SHOWERS AND TSTMS REFLECTED IN HIGHER
POPS SATURDAY INTO MONDAY.
STAYED QUITE CLOSE TO GUIDANCE WITH TEMPERATURES THROUGH THE
EXTENDED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 520 PM MDT TUE SEP 3 2013
ISOLATED SHRA/TSRA ARE POSSIBLE MAINLY ON THE SD PLAINS TONIGHT. OTHERWISE
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...MLS
LONG TERM...BARBER
AVIATION...HELGESON
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1154 PM CDT SUN SEP 1 2013
.UPDATE...
UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT OVERALL EXPECTED
DECREASE IN AREAL COVERAGE OF SHWRS/TSTMS ACROSS THE MID STATE AFTER
MIDNIGHT WITH SOME LOCATIONS EXPERIENCING PATCHY FOG LATE TONIGHT.
&&
.PREV DISCUSSION.../ISSUED 1148 PM CDT SUN SEP 1 2013/
UPDATE...FOR AVIATION.
AVIATION...
06Z TAFS...A BATCH OF SHOWERS WAS MOVING TOWARD BNA AND MAY
BRIEFLY DIP VSBYS TO MVFR BEFORE 08Z. OTHERWISE SHOULD BE A QUITE
NIGHT WITH AREAS OF MAINLY MVFR FOG. FOR MONDAY...AN APPROACHING
FRONT WILL BRING SCT TSRA AFTER 02/18Z. OUTSIDE STORMS...VFR
CONDITIONS WILL PREVAIL. BY THE END OF THE TAF PERIOD...FROPA
WILL SHIFT WINDS TO NNW WITH DRIER AND MORE STABLE AIR ARRIVING.
13
PREV DISCUSSION... /ISSUED 933 PM CDT SUN SEP 1 2013/
UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT ISO TO SCT
SHWRS/TSTMS COMING INTO WRN PORTIONS OF THE MID STATE THIS EVENING.
HAVE UPDATED SKY CONDITIONS TO MOCLDY AND WITH CURRENT TEMP TRENDS...
HAVE LOWERED LOWS BY A DEGREE OR SO. STILL TRICKY FORECAST THRU
TONIGHT AS ATM LOW LEVELS REMAIN RATHER HIGH IN ATM MOISTURE
CONTENT WITH CONTINUED UNSTABLE CONDITIONS...SUBTLE SHORTWAVES IN
UPPER LEVEL PREDOMINATE NWLY FLOW ALOFT INTERACTING...AND SFC
FRONT APPROACHING FROM THE NW BY THE MORNING HRS. HAVE INITIALLY
LEANED TOWARD THE LATEST HRRR MODEL RUNS IN SHOWING SOME ADDITIONAL
DEVELOPMENT FROM THE SW...SPREADING ACROSS THE MID STATE AFTER MIDNIGHT
TONIGHT AS THIS AREA PRESENTLY LOOKS TO HAVE THE BEST OVERALL INSTABILITY
AND MOISTURE POTENTIAL TO SUPPORT SHWR/TSTM DEVELOPMENT.
PREV DISCUSSION... /ISSUED 504 PM CDT SUN SEP 1 2013/
UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT CURRENT AND
EXPECTED EVENING CONDITIONS FOR TONIGHT WITH ONLY A SLIGHT CHANCE
TO CHANCE OF SHWRS/TSTMS ACROSS SW PORTIONS...OTHERWISE PTCLDY SKIES
EXPECTED ACROSS MID STATE. WITH SFC FRONT AND UPPER LEVEL TROUGH AXIS
APPROACHING OVERNIGHT...WENT WITH INCREASING CHANCES OF SHWRS/TSTMS
AFTER MIDNIGHT ACROSS MID STATE.
31
PREV DISCUSSION.../ISSUED 135 PM CDT SUN SEP 1 2013/
DISCUSSION...CLOUDS AND SCATTERED SHOWERS CONTINUE TO AFFECT
PARTS OF MIDDLE TENNESSEE, WITH MOST TEMPERATURES RUNNING WELL
BELOW FORECAST HIGHS. STILL EXPECT SOME SUNSHINE LATER IN THE
AFTERNOON THAT WILL CLOSE THE GAP SOMEWHAT, BUT CLOUDS HAVE REALLY
THROWN A WRENCH INTO TODAY`S FORECAST. AT ANY RATE, THE MAIN
TROUGH AXIS WILL INCH CLOSER TO MIDDLE TENNESSEE OVERNIGHT, WITH
SCATTERED SHOWERS AND STORMS OCCURRING MAINLY DURING THE 06Z-12Z
PERIOD. LOOK FOR SCATTERED ACTIVITY TO CONTINUE TOMORROW AS THE
SURFACE FRONT ENTERS THE MID STATE DURING THE AFTERNOON.
PRECIPITATION WILL END FROM NW TO SE TOMORROW NIGHT AS WE GET A
BIG AIR MASS CHANCE, WITH SIGNIFICANTLY DRIER, COOLER AIR EVIDENT
BY TUESDAY. EXPECT DRY WEATHER FROM TUESDAY AT LEAST THROUGH
SUNDAY, WITH TEMPERATURES GRADUALLY WARMING THROUGHOUT THE WEEK AS
HIGH PRESSURE DOMINATES OUR WEATHER FOR A PROLONGED STRETCH. AT
THIS TIME, THE SPC CONTINUES TO FORECAST ONLY GENERAL
THUNDERSTORMS FOR MIDDLE TENNESSEE THROUGH TOMORROW NIGHT.
ROSE
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1148 PM CDT SUN SEP 1 2013
.UPDATE...FOR AVIATION.
&&
.AVIATION...
06Z TAFS...A BATCH OF SHOWERS WAS MOVING TOWARD BNA AND MAY
BRIEFLY DIP VSBYS TO MVFR BEFORE 08Z. OTHERWISE SHOULD BE A QUITE
NIGHT WITH AREAS OF MAINLY MVFR FOG. FOR MONDAY...AN APPROACHING
FRONT WILL BRING SCT TSRA AFTER 02/18Z. OUTSIDE STORMS...VFR
CONDITIONS WILL PREVAIL. BY THE END OF THE TAF PERIOD...FROPA
WILL SHIFT WINDS TO NNW WITH DRIER AND MORE STABLE AIR ARRIVING.
13
&&
.PREV DISCUSSION... /ISSUED 933 PM CDT SUN SEP 1 2013/
UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT ISO TO SCT
SHWRS/TSTMS COMING INTO WRN PORTIONS OF THE MID STATE THIS EVENING.
HAVE UPDATED SKY CONDITIONS TO MOCLDY AND WITH CURRENT TEMP TRENDS...
HAVE LOWERED LOWS BY A DEGREE OR SO. STILL TRICKY FORECAST THRU
TONIGHT AS ATM LOW LEVELS REMAIN RATHER HIGH IN ATM MOISTURE
CONTENT WITH CONTINUED UNSTABLE CONDITIONS...SUBTLE SHORTWAVES IN
UPPER LEVEL PREDOMINATE NWLY FLOW ALOFT INTERACTING...AND SFC
FRONT APPROACHING FROM THE NW BY THE MORNING HRS. HAVE INITIALLY
LEANED TOWARD THE LATEST HRRR MODEL RUNS IN SHOWING SOME ADDITIONAL
DEVELOPMENT FROM THE SW...SPREADING ACROSS THE MID STATE AFTER MIDNIGHT
TONIGHT AS THIS AREA PRESENTLY LOOKS TO HAVE THE BEST OVERALL INSTABILITY
AND MOISTURE POTENTIAL TO SUPPORT SHWR/TSTM DEVELOPMENT.
PREV DISCUSSION... /ISSUED 504 PM CDT SUN SEP 1 2013/
UPDATE...
HAVE UPDATED THE SUITE OF FORECAST PRODUCTS TO REFLECT CURRENT AND
EXPECTED EVENING CONDITIONS FOR TONIGHT WITH ONLY A SLIGHT CHANCE
TO CHANCE OF SHWRS/TSTMS ACROSS SW PORTIONS...OTHERWISE PTCLDY SKIES
EXPECTED ACROSS MID STATE. WITH SFC FRONT AND UPPER LEVEL TROUGH AXIS
APPROACHING OVERNIGHT...WENT WITH INCREASING CHANCES OF SHWRS/TSTMS
AFTER MIDNIGHT ACROSS MID STATE.
31
PREV DISCUSSION.../ISSUED 135 PM CDT SUN SEP 1 2013/
DISCUSSION...CLOUDS AND SCATTERED SHOWERS CONTINUE TO AFFECT
PARTS OF MIDDLE TENNESSEE, WITH MOST TEMPERATURES RUNNING WELL
BELOW FORECAST HIGHS. STILL EXPECT SOME SUNSHINE LATER IN THE
AFTERNOON THAT WILL CLOSE THE GAP SOMEWHAT, BUT CLOUDS HAVE REALLY
THROWN A WRENCH INTO TODAY`S FORECAST. AT ANY RATE, THE MAIN
TROUGH AXIS WILL INCH CLOSER TO MIDDLE TENNESSEE OVERNIGHT, WITH
SCATTERED SHOWERS AND STORMS OCCURRING MAINLY DURING THE 06Z-12Z
PERIOD. LOOK FOR SCATTERED ACTIVITY TO CONTINUE TOMORROW AS THE
SURFACE FRONT ENTERS THE MID STATE DURING THE AFTERNOON.
PRECIPITATION WILL END FROM NW TO SE TOMORROW NIGHT AS WE GET A
BIG AIR MASS CHANCE, WITH SIGNIFICANTLY DRIER, COOLER AIR EVIDENT
BY TUESDAY. EXPECT DRY WEATHER FROM TUESDAY AT LEAST THROUGH
SUNDAY, WITH TEMPERATURES GRADUALLY WARMING THROUGHOUT THE WEEK AS
HIGH PRESSURE DOMINATES OUR WEATHER FOR A PROLONGED STRETCH. AT
THIS TIME, THE SPC CONTINUES TO FORECAST ONLY GENERAL
THUNDERSTORMS FOR MIDDLE TENNESSEE THROUGH TOMORROW NIGHT.
ROSE
&&
.OHX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
631 PM CDT TUE SEP 3 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 239 PM CDT TUE SEP 3 2013
..CURRENTLY AS OF 19Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW
JUST OFF THE PACIFIC NORTHWEST COAST...SUBTROPICAL RIDGING FROM
COLORADO INTO ALBERTA...AND TROUGHING FROM HUDSON BAY DOWN ALONG THE
EAST COAST OF THE U.S.. WITHIN THIS TROUGHING...THE MAIN FEATURE OF
NOTE IS A POTENT SHORTWAVE DROPPING THROUGH NORTHERN MANITOBA AND
ONTARIO...WHICH IS REFLECTED AT THE SURFACE BY A COLD FRONT THAT IS
APPROACHING FAR NORTHWEST MN. HIGH PRESSURE AND DRY AIR DOMINATE THE
FORECAST AREA. THE DRY AIR IS REFLECTED WELL ON THE 12Z SOUNDINGS
FROM MPX...GRB AND DVN WITH PRECIPITABLE WATER VALUES AROUND 0.68
INCHES OR 80 PERCENT OF NORMAL. SOME MID AND HIGH CLOUDS HAVE BEEN
SPREADING INTO THE AREA FROM THE DAKOTAS AND MINNESOTA...ASSOCIATED
WITH SOME WEAK 850MB MOISTURE TRANSPORT AHEAD OF THE COLD FRONT...AS
WELL AS WEAK 320K ISENTROPIC LIFT. THE MID AND HIGH CLOUDS ALSO
REFLECT SEPARATION OF WARMTH ACROSS THE UPPER MIDWEST. 12Z SOUNDINGS
FROM BIS AND ABR HAD 925MB TEMPS AROUND 20C...WHEREAS GRB...DVN AND
MPX WERE AROUND 12C.
..HAZARDS..
NONE.
..SYNOPTIC OVERVIEW..
03.12Z MODEL GUIDANCE REMAINS CONSISTENT IN DEVELOPING AN
ANOMALOUSLY DEEP TROUGH OVER THE HUDSON BAY REGION DURING THE NEXT
24 HOURS. THIS TROUGH HELPS PROPEL THE COLD FRONT CURRENTLY DROPPING
INTO NORTHWEST MN THROUGH THE FORECAST AREA DURING THE DAY
WEDNESDAY. CANADIAN HIGH PRESSURE LOOKS TO BUILD INTO NORTHERN MN
AND UPPER MI BEHIND THE FRONT LATE WEDNESDAY.
..DETAILS..
PLENTIFUL DRY AIR IN THE LOW LEVELS OF THE TROPOSPHERE FOR THE NEXT
24 HOURS...COMBINED WITH CAPPING ADVECTING IN AT 800MB AHEAD OF THE
COLD FRONT DROPPING SOUTH WILL HELP TO KEEP CONDITIONS DRY THROUGH
THE SHORT TERM PERIOD. 03.12Z NAM BMJ CONVECTIVE SCHEME GOES OFF
WEDNESDAY AFTERNOON WEST OF THE MISSISSIPPI RIVER...BUT THINK IT IS
REMOVING THE CAPPING WAY TOO QUICK GIVEN THAT THE 03.12Z GFS DEPICTS
160 J/KG OF CIN AT THE SAME TIME.
ALTHOUGH CONDITIONS ARE EXPECTED TO BE DRY...THERE ARE SOME CLOUD
COVER CONCERNS WHICH TIE INTO TEMPERATURES AND POTENTIAL FOR VALLEY
FOG. INDICATIONS ARE THAT THE CURRENT CIRRUS OVER THE FORECAST AREA
WILL CLEAR THE AREA THIS EVENING. THE NEXT BATCH OF MID/HIGH CLOUDS
UPSTREAM OVER SOUTHERN SASKATCHEWAN AND NORTHERN NORTH DAKOTA LOOK
TO MOVE INTO THE AREA LATE TONIGHT AND PERSIST THROUGH MUCH OF
TOMORROW. GOOD RADIATIONAL COOLING CONDITIONS EXIST BETWEEN THE TWO
BATCHES OF CLOUDS...WHICH SHOULD ALLOW TEMPS TO BOTTOM OUT INTO THE
UPPER 40S TO MID 50S. THE INCREASE IN CLOUDS LATE TONIGHT ALONG WITH
MODELS INCREASING 950-975MB WINDS AHEAD OF THE FRONT SHOULD KEEP ANY
VALLEY FOG THAT FORMS TO MOSTLY THE MISSISSIPPI RIVER TRIBUTARIES...
THOUGH CANNOT RULE OUT PATCHES OF FOG IN THE MISSISSIPPI RIVER
VALLEY. 925MB TEMPS ON WEDNESDAY ARE PROGGED TO CLIMB TO 19-24C...
COOLEST OVER TAYLOR COUNTY. THESE READINGS COMBINED WITH SUNSHINE
FILTERING THROUGH THE CLOUDS WILL ALLOW HIGHS TO TOP OUT IN THE
UPPER 70S TO MID 80S. A FEW SPOTS MAY EVEN HIT THE UPPER 80S...
DEPENDING ON THE AMOUNT OF SUN...AND MOST LIKELY TO OCCUR IN THE
WISCONSIN RIVER VALLEY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 239 PM CDT TUE SEP 3 2013
..HAZARDS..
1. HEAT. MODELS ARE HINTING AT A SURGE OF HEAT COMING INTO THE
FORECAST AREA ON SATURDAY. RIGHT NOW IT APPEARS HEAT INDICES WILL
STAY BELOW ADVISORY CRITERIA...THOUGH.
2. STORMS. THERE ARE CHANCES IN THE FORECAST FOR FRIDAY NIGHT AND
BEYOND. IF THERE IS ANY SEVERE POSSIBILITY...IT WOULD COME EARLY
NEXT WEEK...BUT THERE IS STILL PLENTY OF TIME FOR THIS TO CHANGE.
..SYNOPTIC OVERVIEW..
03.12Z ECMWF/GFS/CANADIAN AND ENSEMBLE DATA ALL SUGGEST A SLOW
PROGRESSION EASTWARD OF THE UPPER LEVEL PATTERN DURING THE NEXT 7
DAYS. MUCH OF THIS PROGRESSION HAS TO WAIT UNTIL FRIDAY BECAUSE OF
THE ANOMALOUSLY DEEP TROUGH SET UP OVER THE HUDSON BAY REGION AND
SOUTHEAST CANADA. BY MONDAY...MODELS PROG THAT THE UPPER LOW
CURRENTLY OFF THE PACIFIC NORTHWEST COAST WILL HAVE SLID INLAND INTO
MONTANA...WHILE THE RIDGE AXIS AHEAD OF IT OVER ALBERTA MOVES EAST
TO OVER THE FORECAST AREA. THEN FOR TUESDAY...INDICATIONS ARE THAT
TROUGHING WILL BE CROSSING MANITOBA...SENDING A COLD FRONT TOWARDS
THE AREA. THE CHANGE IN THE UPPER LEVEL PATTERN MEANS THAT BY THE
WEEKEND...WARM AIR ADVECTION WILL BE IN FORCE...BRINGING CONCERNS OF
CAPPING...PRECIPITATION AND POSSIBLY MUGGY CONDITIONS AGAIN.
..DETAILS..
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...DRY CONDITIONS WILL
DOMINATE THIS PERIOD WITH SUBSIDENCE AND DRY AIR IN PLACE...ALONG
WITH HIGH PRESSURE TRACKING SOUTHEAST ACROSS THE WESTERN GREAT LAKES
REGION. SKIES SHOULD CLEAR OUT NORTH TO SOUTH WEDNESDAY NIGHT AS THE
UPPER FLOW TURNS A BIT MORE NORTHERLY...FOLLOWED BY FULL SUN ON
THURSDAY AND SOME INCREASE IN WARM ADVECTION MID/HIGH CLOUDS LATE
THURSDAY NIGHT. VALLEY FOG CONCERNS...AT LEAST IN THE MISSISSIPPI
RIVER...SHOULD BE MINIMIZED BY POTENTIAL ISSUES WITH CLOUDS AND AN
EASTERLY BREEZE RIGHT ABOVE THE SURFACE. LOWS WILL ALSO BE ON THE
COOL SIDE...ESPECIALLY IN WISCONSIN WHERE THE HIGH TRACKS ACROSS.
HIGHS ON THURSDAY SHOULD BE A LITTLE COOLER THAN WEDNESDAY DUE TO
925MB TEMPS TOPPING OUT BETWEEN 18-22C.
FRIDAY THROUGH TUESDAY...FOCUS IS ON THE WARM ADVECTION PATTERN THAT
DEVELOPS.
1. TEMPERATURES...850MB ANOMALIES ARE PROGGED BETWEEN 0.5-1 ABOVE ON
FRIDAY AND SUNDAY...AND 1.5-2 ABOVE FOR SATURDAY...MONDAY AND
TUESDAY. THESE WILL KEEP US BELOW RECORDS BUT ABOVE TO WELL ABOVE
NORMAL NONETHELESS. 925MB TEMPS CLIMB TO 22-26C ON FRIDAY...24-29C
ON SATURDAY...COOL TO 18-21C ON SUNDAY AND MONDAY AND CLIMB BACK UP
TO 24-29C ON TUESDAY. THE WARMEST READINGS ARE SUGGESTED OVER
NORTHEAST IOWA. MEANWHILE...THE COOLEST READINGS ARE PROGGED OVER
TAYLOR/CLARK COUNTIES WHICH ARE CLOSER TO A CANADIAN HIGH TRACKING
ACROSS SOUTH CENTRAL CANADA AND THE UPPER GREAT LAKES.
2. MUGGY-NESS...GULF OF MEXICO MOISTURE WILL RETURN BACK INTO THE
REGION BUT ITS GOING TO TAKE SOME TIME DUE TO THE CANADIAN HIGH
MOVING ACROSS ON THURSDAY. ADDITIONALLY...THE DROUGHT CONDITIONS
THAT HAVE DEVELOPED WILL HELP TO MIX OUT THIS MOISTURE. THE BETTER
SHOT FOR MORE MUGGY CONDITIONS LOOKS TO COME THIS THE WEEKEND INTO
EARLY NEXT WEEK AS MOISTURE POOLS ALONG A FRONTAL BOUNDARY PROGGED
TO SET UP NEAR THE FORECAST AREA. EVEN STILL...DEWPOINTS DO NOT
APPEAR AS HIGH AS THEY WERE DURING THE HEAT WAVE LAST WEEK.
3. PRECIPITATION CHANCES...MODELS ARE IN GOOD AGREEMENT HOLDING
FRIDAY DRY. THERE COULD BE SOME ELEVATED CONVECTION ON THE EDGE OF
THE WARM SURGE / CAPPING OVER WISCONSIN FRIDAY NIGHT AND SATURDAY...
AND HAVE 20-30 PERCENT CHANCES FOR THEM. FROM SATURDAY NIGHT
ONWARDS...ALL BETS ARE OFF WITH THE 03.12Z ECMWF/CANADIAN/GFS ALL
SHOWING PERIODS OF PRECIPITATION. VERY HARD TO PIN THESE
DOWN...GIVEN FRONTAL BOUNDARY POSITION UNCERTAINTY. ADDITIONALLY...
THE IMPACT OF THE DROUGHT COULD END UP LIMITING THE AMOUNT OF
PRECIPITATION...PARTICULARLY IN THE DAYTIME. FOR NOW FOLLOWED A
MODEL CONSENSUS OF GENERALLY 20-40 PERCENT CHANCES EVERY 12 HOURS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 631 PM CDT TUE SEP 3 2013
THE TWO MAIN THINGS TO WATCH INTO TOMORROW ARE WITH WHETHER ANY
VALLEY FOG WILL FORM TONIGHT AND THEN WHEN A COLD FRONT WILL COME
THROUGH. THERE ARE SOME POSITIVES AND NEGATIVES FOR THE VALLEY FOG
FORMATION. THE MAIN NEGATIVES ARE WITH THE INCREASING MID TO UPPER
LEVEL CLOUD COVER ALONG WITH A TIGHTENING LOW LEVEL PRESSURE
GRADIENT THAT WILL LEAD TO INCREASING WINDS AS A COLD FRONT
APPROACHES FROM THE NORTH. THE POSITIVES ARE THAT SURFACE WINDS
WILL GENERALLY BE LIGHT OUT OF THE WEST AND DEW POINTS SHOULD ALSO
STAY UP AS WELL. SO...THE MAIN QUESTIONS WILL BE WITH HOW STRONG
THE WINDS WILL BE AND HOW MUCH CLOUD COVER WILL BE AROUND
OVERNIGHT. BECAUSE OF THESE QUESTIONS...HAVE KEPT THE 4SM/SCT002
IN AND WILL EVALUATE IT MORE THIS EVENING. THE COLD FRONT LOOKS
LIKE IT WILL COME THROUGH IN THE MORNING AROUND 13-15Z WITH WINDS
COMING AROUND FROM THE SOUTHWEST TO THE NORTHWEST AFTER IT PASSES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
245 PM CDT MON SEP 2 2013
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 245 PM CDT MON SEP 2 2013
THICK BLANKET OF CLOUDS ACROSS WI AND PARTS OF EASTERN MN EARLY THIS
AFTERNOON...ON THE BACKSIDE OF A EASTWARD DEPARTING LOW PRESSURE
SYSTEM. THE LATEST HRRR AND SREF POINT TO SOMEWHAT RAPID
DISSIPATION/EXITING EAST OF THIS CLOUD DECK AS THE AFTERNOON WEARS
ON. MUCH OF THIS WOULD BE DUE TO THE MIXING IN OF DRY AIR AS A SFC
HIGH SLIDES IN FROM THE NORTHERN PLAINS. THAT SAID...SATELLITE STILL
DEPICTS THE ORIGINAL CLOUD SHIELD FAIRLY WELL...MORE A
NORTHWEST-SOUTHEAST RUNNING BAND. RAP13/NAM12 RH FIELDS HANG ONTO TO
SOME OF THIS SATURATION OVER NORTHEAST IA/SOUTHWEST WI THROUGH THE
OVERNIGHT. GOING TO SIDE WITH THE CLEARING TREND...HOLDING ONTO
CLOUDS THE LONGEST IN THE SOUTH. ADD A LIGHT NEAR SFC WIND FIELD
INTO THE MIX AND CLIMATOLOGICALLY FAVORED TIME OF YEAR AND RIVER
VALLEY FOG SHOULD DEVELOP...LIKELY BECOMING DENSE AT SOME LOCATIONS.
MOST OF WHAT DEVELOPS SHOULD BURN OFF BY 9-10 AM. THERE IS SOME
CONCERN THAT FOG COULD FORM OUTSIDE OF THE VALLEYS. THERE WAS SOME
FOG TO THE WEST UNDER THE HIGH EARLY THIS MORNING...BUT SOME OF
THIS WAS IN LOCATIONS THAT HAD RECENT RAINS. WE HAVE BEEN
EXCEEDINGLY DRY...AND DESPITE THE DEVELOPING CLEAR SKIES/LIGHT
WINDS...FOG DEVELOPMENT COULD BE INHIBITED BY THE DRY CONDITIONS.
MAY ADD IN SOME PATCHY FOG AREAWIDE. IF NOT...CONDITIONS WILL HAVE
TO BE MONITORED AND ADJUSTMENTS MADE TO FORECAST IF FOG LOOKS MORE
LIKELY. DON/T FEEL A DENSE FOG ADVISORY IS LIKELY. IF IT WOULD HAVE
RAINED RECENTLY...THAT WOULD BE A DIFFERENT STORY.
HIGH PRESSURE AND A COLD/DRY INFLUX OF AIR WILL GET THE SHORTENED
WORK WEEK OFF TO A CHILLY START. 850 MB TEMP ANOMALIES AROUND -1
TODAY INTO TUE MORNING. WITH PLENTY OF RADIATIONAL COOLING FROM
CLEARING SKIES...LIGHT WINDS...AND THE AFOREMENTIONED COLD AIR
ADVECTING IN...LOWS NEAR 40 ARE LIKELY IN SOME OF THE COLD DRAINAGE
AND LOW LYING AREAS OF CENTRAL/NORTH CENTRAL WI. ELSEWHERE 40S TO
NEAR 50 WILL BE THE RULE...ABOUT 10 TO 15 DEGREES BELOW NORMAL.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 245 PM CDT MON SEP 2 2013
A SURFACE HIGH WILL MEANDER SLOWLY SOUTHEAST ACROSS THE
REGION...WHILE AN UPPER LEVEL RIDGE HOLDS TO THE WEST FOR THE
SHORTENED WORK WEEK. MODELS FAVORING KEEPING ANY PERTURBATIONS ALONG
THE UPPER LEVEL FLOW NORTH/SOUTH OF THE FORECAST AREA...THUS DRY
CONDITIONS WILL CONTINUE.
SOME HOPE FOR RAIN TOWARD THE LATER PART OF THE WEEKEND AND EARLY
NEXT WEEK. THE RIDGE AXIS SHIFTS OVER THE UPPER MISSISSIPPI ON
SUNDAY...WITH AN UPPER LEVEL SHORTWAVE ROLLING ACROSS THE RIDGE TOP
MON/TUE...FLATTENING IT OUT. A SFC WARM FRONT WILL SWEEP AHEAD OF
THE UPPER LEVEL FORCING...WITH THE GFS/EC DEVELOPING PCPN WITH THIS
THERMODYNAMIC LIFT ON SUNDAY. PCPN CHANCES WOULD HANG THROUGH MONDAY
UNTIL THE UPPER LEVEL TROUGH AND ITS ASSOCIATED COLD FRONT MOVE
THROUGH LATER ON TUE. SOME DIFFERENCES IN TIMING ON WHEN THE VARIOUS
FEATURES WOULD MOVE IN...AND THUS ON THE PCPN CHANCES. ALL
SAID...IT LOOKS LIKE THE BEST SHOT FOR WIDESPREAD RAIN FOR THE LOCAL
AREA. WILL SIDE WITH THE CONSENSUS SOLUTION FOR PCPN CHANCES FOR
NOW.
TEMPERATURES WILL BE ON A SLOW RISE THROUGH THE WEEK...WITH A COUPLE
FAIRLY WARM DAYS FOR EARLY SEPT ON FRI/SAT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED
AT 1223 PM CDT MON SEP 2 2013
MVFR STRATUS DECK PERSISTS ACROSS THE AREA EARLY THIS AFTERNOON.
SOUNDINGS SHOW THIS MOISTURE/CLOUDS TRAPPED UNDER A VERY STRONG
SUBSIDENCE INVERSION NEAR 875MB...LIMITING MIXING/DISSIPATION OF THE
CLOUD DECKS AT MID-DAY. BASED ON SATELLITE IMAGERY...TRENDED TAFS
THRU 00Z MORE PESSIMISTIC WITH THE CLOUD DECK VERY SLOWLY LIFTING/
MIXING/BREAKING UP. CONCERN IS THESE CLOUDS WILL LINGER INTO THE
EVENING...BUT MODELS/SOUNDINGS INSIST THE TRAPPED LOW LEVEL MOISTURE
WILL ADVECT OUT OF THE AREA BY OR SHORTLY AFTER 00Z.
RATHER DRY AIRMASS ABOVE THE 875MB INVERSION...SO ONCE CLOUDS ARE
GONE...VERY FAVORABLE FOR STRONG RADIATIONAL COOLING TONIGHT WITH
THE SFC-925MB RIDGE AXIS OVER THE AREA AT 12Z TUE. BR/FG EXPECTED TO
FORM IN THE RIVER VALLEYS AND OTHER FAVORED LOW LAYING AREAS IN
ROUGHLY THE 09Z-15Z TIME-FRAME. CLOUDS AND COOLER HIGHS TODAY MAY
MAKE MVFR/IFR CIGS/VSBYS IN BR/FG MORE WIDESPREAD THAN EARLIER
THOUGHT...BUT LEFT THIS AS 1/2SM FG BKN003 AT KLSE FOR NOW GIVEN THE
UNCERTAINTIES OF THE STRATUS DECK DISSIPATION/CLEARING. ONCE ANY
BR/FG WOULD BURN OFF BY MID MORNING...GOOD VFR EXPECTED TUE UNDER
DRY HIGH PRESSURE AND SFC-500MB RIDGING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1222 PM CDT MON SEP 2 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 422 AM CDT MON SEP 2 2013
FORECAST CONCERNS ON CLOUD TRENDS TODAY.
UPPER TROF CONTINUES TO MOVE TO THE EAST THIS MORNING. SAT
IMAGERY SHOWING LOW CLOUDS DROPPING SOUTH THROUGH THE WESTERN
LAKES BEHIND SYSTEM. CLOUDS HAVE HAD A HARD TIME FILLING IN OVER
THE SOUTHERN CWA...ESPECIALLY IN THE EAST WHERE DOWNSLOPE
COMPONENT OF NW WINDS OPENING HOLES. SCATTERED LIGHT SHOWERS
CONTINUE OVER NORTH CENTRAL WI WITH RHI PICKING UP ANOTHER .01
LAST HOUR.
CANADIAN HIGH PRESSURE WILL CONTINUE TO MOVE SOUTHEAST INTO THE
STATE TODAY. INCREASING SUBSIDENCE AND ADVECTION OF DRIER AIR
INTO THE REGION SHOULD WORK TO ERODE THE CLOUDS THROUGH THE DAY.
DECREASING INVERSION HEIGHTS WILL ALSO LIMIT LAKE SUPERIOR CONTRIBUTION
TO THE CLOUDS AND PCPN. GEM REGIONAL AND HRRR APPEAR TO BE
HANDLING CURRENT CLOUD TRENDS AND HAVE LEANED TOWARDS THEIR
THOUGHTS OF CLEARING BY LATER AFTERNOON. WILL CONTINUE TO CARRY
SOME TRACE LIGHT SHOWERS OVER NORTH CENTRAL INTO THE LATER
MORNING. NO SIGNIFICANT CHANGE MADE TO PREVIOUS TEMP FORECAST.
SFC HIGH PRESSURE TO BE CONTROL WEATHER OVER STATE THROUGH TUE.
LOOKING FOR CLEAR SKIES AND LIGHT WINDS. HAVE TRENDED A BIT COOLER
TONIGHT IN THE TYPICAL COOLER LOCATIONS...THOUGH SHOULD SEE SIG
DIURNAL SWING FOR TUE FOR TEMPS TO RECOVER BACK TO NEAR SEASONAL
NORMS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 422 AM CDT MON SEP 2 2013
THE UPPER LEVEL RIDGE AMPLIFYING OVER THE WESTERN CONUS IS THE
MAIN FEATURE DURING THIS PART OF THE FORECAST. SURFACE HIGH
PRESSURE OVER THE REGION AT THE START OF THE PERIOD WILL PUSH
SOUTHWARD AS A COLD FRONT MOVES THROUGH WISCONSIN MIDWEEK. ANY
UPPER LEVEL SUPPORT REMAINS FAR TO THE NORTHEAST AND THERE IS
LITTLE MOISTURE AROUND SO A DRY FRONTAL PASSAGE IS EXPECTED.
COOLER CONDITIONS BEHIND THE FRONT SHOULD NOT LAST LONG AS SURFACE
WINDS BECOME MORE SOUTHERLY AND BRING WARMER AIR BACK TO THE AREA.
ANOTHER COLD FRONT AND SOME WEAK SHORT WAVE ENERGY WILL BRING A
CHANCE FOR SHOWERS OR STORMS TO THE AREA...MAINLY EARLY NEXT WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1222 PM CDT MON SEP 2 2013
COMBINATION OF MID-LEVEL CYCLONIC FLOW AND 8H COLD
POOL HAS PROVIDED A SUBSIDENCE INVERSION THAT HAS YET TO BE
BROKEN...THEREFORE KEEPING MAINLY MVFR CIGS ACROSS NE WI. WHILE
SOME BREAKS IN THE CLOUDS ARE EXPECTED WITH SOME CIGS BECOMING
VFR...EXPECT MOST OF THESE CLOUDS TO HANG AROUND TIL SUNSET BEFORE
FINALLY BREAKING UP. A RDG OF HI PRES IS FCST TO BUILD INTO WI
LATER TONIGHT AND BE PARKED OVER THE GREAT LAKES ON TUE. VFR
CONDITIONS SHOULD RULE UNDER MOSTLY CLEAR SKIES.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......AK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
641 AM CDT MON SEP 2 2013
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 422 AM CDT MON SEP 2 2013
FORECAST CONCERNS ON CLOUD TRENDS TODAY.
UPPER TROF CONTINUES TO MOVE TO THE EAST THIS MORNING. SAT
IMAGERY SHOWING LOW CLOUDS DROPPING SOUTH THROUGH THE WESTERN
LAKES BEHIND SYSTEM. CLOUDS HAVE HAD A HARD TIME FILLING IN OVER
THE SOUTHERN CWA...ESPECIALLY IN THE EAST WHERE DOWNSLOPE
COMPONENT OF NW WINDS OPENING HOLES. SCATTERED LIGHT SHOWERS
CONTINUE OVER NORTH CENTRAL WI WITH RHI PICKING UP ANOTHER .01
LAST HOUR.
CANADIAN HIGH PRESSURE WILL CONTINUE TO MOVE SOUTHEAST INTO THE
STATE TODAY. INCREASING SUBSIDENCE AND ADVECTION OF DRIER AIR
INTO THE REGION SHOULD WORK TO ERODE THE CLOUDS THROUGH THE DAY.
DECREASING INVERSION HEIGHTS WILL ALSO LIMIT LAKE SUPERIOR CONTRIBUTION
TO THE CLOUDS AND PCPN. GEM REGIONAL AND HRRR APPEAR TO BE
HANDLING CURRENT CLOUD TRENDS AND HAVE LEANED TOWARDS THEIR
THOUGHTS OF CLEARING BY LATER AFTERNOON. WILL CONTINUE TO CARRY
SOME TRACE LIGHT SHOWERS OVER NORTH CENTRAL INTO THE LATER
MORNING. NO SIGNIFICANT CHANGE MADE TO PREVIOUS TEMP FORECAST.
SFC HIGH PRESSURE TO BE CONTROL WEATHER OVER STATE THROUGH TUE.
LOOKING FOR CLEAR SKIES AND LIGHT WINDS. HAVE TRENDED A BIT COOLER
TONIGHT IN THE TYPICAL COOLER LOCATIONS...THOUGH SHOULD SEE SIG
DIURNAL SWING FOR TUE FOR TEMPS TO RECOVER BACK TO NEAR SEASONAL
NORMS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 422 AM CDT MON SEP 2 2013
THE UPPER LEVEL RIDGE AMPLIFYING OVER THE WESTERN CONUS IS THE
MAIN FEATURE DURING THIS PART OF THE FORECAST. SURFACE HIGH
PRESSURE OVER THE REGION AT THE START OF THE PERIOD WILL PUSH
SOUTHWARD AS A COLD FRONT MOVES THROUGH WISCONSIN MIDWEEK. ANY
UPPER LEVEL SUPPORT REMAINS FAR TO THE NORTHEAST AND THERE IS
LITTLE MOISTURE AROUND SO A DRY FRONTAL PASSAGE IS EXPECTED.
COOLER CONDITIONS BEHIND THE FRONT SHOULD NOT LAST LONG AS SURFACE
WINDS BECOME MORE SOUTHERLY AND BRING WARMER AIR BACK TO THE AREA.
ANOTHER COLD FRONT AND SOME WEAK SHORT WAVE ENERGY WILL BRING A
CHANCE FOR SHOWERS OR STORMS TO THE AREA...MAINLY EARLY NEXT WEEK.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 624 AM CDT MON SEP 2 2013
COOL NORTH-NORTHWEST FLOW ACROSS WESTERN LAKE SUPERIOR WILL
CONTINUE TO BRING ISOLD TO SCT LIGHT LAKE-EFFECT RAIN SHOWERS AND
MVFR/IFR CIGS TO MUCH OF NORTH CENTRAL THIS MORNING. THE CLOUDS
ARE MORE VARIABLE OVER NORTHEAST AND CENTRAL WISCONSIN WITH
SCATTERED TO BROKEN CIGS IN MVFR/VFR RANGE. DAYTIME HEATING AND
THE ARRIVAL OF DRIER AIR SHOULD CAUSE CIGS TO RISE TO VFR THERE BY
LATE MORNING...FOLLOWED BY DECREASING CLOUDS LATE IN THE DAY.
CLEAR SKIES EXPECTED TONIGHT AND TUESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......TE
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SHORT TERM...TODAY...TONIGHT...AND TUESDAY
ISSUED AT 422 AM CDT MON SEP 2 2013
FORECAST CONCERNS ON CLOUD TRENDS TODAY.
UPPER TROF CONTINUES TO MOVE TO THE EAST THIS MORNING. SAT
IMAGERY SHOWING LOW CLOUDS DROPPING SOUTH THROUGH THE WESTERN
LAKES BEHIND SYSTEM. CLOUDS HAVE HAD A HARD TIME FILLING IN OVER
THE SOUTHERN CWA...ESPECIALLY IN THE EAST WHERE DOWNSLOPE
COMPONENT OF NW WINDS OPENING HOLES. SCATTERED LIGHT SHOWERS
CONTINUE OVER NORTH CENTRAL WI WITH RHI PICKING UP ANOTHER .01
LAST HOUR.
CANADIAN HIGH PRESSURE WILL CONTINUE TO MOVE SOUTHEAST INTO THE
STATE TODAY. INCREASING SUBSIDENCE AND ADVECTION OF DRIER AIR
INTO THE REGION SHOULD WORK TO ERODE THE CLOUDS THROUGH THE DAY.
DECREASING INVERSION HEIGHTS WILL ALSO LIMIT LAKE SUPERIOR CONTRIBUTION
TO THE CLOUDS AND PCPN. GEM REGIONAL AND HRRR APPEAR TO BE
HANDLING CURRENT CLOUD TRENDS AND HAVE LEANED TOWARDS THEIR
THOUGHTS OF CLEARING BY LATER AFTERNOON. WILL CONTINUE TO CARRY
SOME TRACE LIGHT SHOWERS OVER NORTH CENTRAL INTO THE LATER
MORNING. NO SIGNIFICANT CHANGE MADE TO PREVIOUS TEMP FORECAST.
SFC HIGH PRESSURE TO BE CONTROL WEATHER OVER STATE THROUGH TUE.
LOOKING FOR CLEAR SKIES AND LIGHT WINDS. HAVE TRENDED A BIT COOLER
TONIGHT IN THE TYPICAL COOLER LOCATIONS...THOUGH SHOULD SEE SIG
DIURNAL SWING FOR TUE FOR TEMPS TO RECOVER BACK TO NEAR SEASONAL
NORMS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY
ISSUED AT 422 AM CDT MON SEP 2 2013
THE UPPER LEVEL RIDGE AMPLIFYING OVER THE WESTERN CONUS IS THE
MAIN FEATURE DURING THIS PART OF THE FORECAST. SURFACE HIGH
PRESSURE OVER THE REGION AT THE START OF THE PERIOD WILL PUSH
SOUTHWARD AS A COLD FRONT MOVES THROUGH WISCONSIN MIDWEEK. ANY
UPPER LEVEL SUPPORT REMAINS FAR TO THE NORTHEAST AND THERE IS
LITTLE MOISTURE AROUND SO A DRY FRONTAL PASSAGE IS EXPECTED.
COOLER CONDITIONS BEHIND THE FRONT SHOULD NOT LAST LONG AS SURFACE
WINDS BECOME MORE SOUTHERLY AND BRING WARMER AIR BACK TO THE AREA.
ANOTHER COLD FRONT AND SOME WEAK SHORT WAVE ENERGY WILL BRING A
CHANCE FOR SHOWERS OR STORMS TO THE AREA...MAINLY EARLY NEXT WEEK.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1140 PM CDT SUN SEP 1 2013
COOL NORTH-NORTHWEST FLOW ACROSS WESTERN LAKE SUPERIOR WILL BRING
SCT LAKE-EFFECT RAIN SHOWERS AND MVFR/IFR CIGS TO MUCH OF NORTH
CENTRAL AND FAR NE WI OVERNIGHT INTO MONDAY MORNING. DAYTIME
HEATING AND THE ARRIVAL OF DRIER AIR SHOULD CAUSE CIGS TO RISE TO
VFR THERE BY LATE MORNING...FOLLOWED BY DECREASING CLOUDS LATE
IN THE DAY. VFR CONDITIONS SHOULD PREVAIL OVER MUCH OF EASTERN
WI...AIDED BY DOWNSLOPING NW WINDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....TE
LONG TERM......MG
AVIATION.......KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
322 AM CDT MON SEP 2 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 322 AM CDT MON SEP 2 2013
CLOUDS TODAY/TEMPERATURES TODAY AND TONIGHT/FOG TONIGHT ALL TOPICS
OF CONCERN THROUGH THE SHORT TERM.
SATELLITE AND SURFACE ANALYSIS HAVE A 1002MB LOW PRESSURE CENTERED
JUST NORTH OF LAKE HURON. CYCLONIC CIRCULATION ON THE BACKSIDE OF
THIS LOW WAS ROTATING A MASS OF STRATOCUMULUS SOUTHWARD ACROSS
NORTHERN MN/WI TOWARD THE FORECAST AREA. AS OF 3 AM...THE SOUTHERN
EXTENT/FRINGE OF THIS STRATOCUMULUS WAS APPROACHING THE I-94
CORRIDOR. SURFACE OBSERVATIONS WERE ALSO INDICATING SOME
INTERMITTENT VERY LIGHT RAIN SHOWER ACTIVITY WITHIN THIS CLOUD FIELD
ACROSS NORTHEAST WI.
WE WILL CONTINUE TO SEE THAT STRATOCUMULUS CLOUD FIELD INVADE THE
FORECAST AREA THROUGH THIS LABOR DAY MORNING...THEN SLOWLY ERODE
FROM WEST TO EAST THIS AFTERNOON AS A STRONG RIDGE OF HIGH PRESSURE
BUILDS IN FROM THE NORTHERN PLAINS. WAS CONTEMPLATING INCLUDING SOME
MENTION OF SHOWERS FOR AREAS NORTHEAST OF I-94 BUT THINK ANY CHANCES
SHOULD REMAINED CONFINED TO NORTHEAST WI IN DEEPER CYCLONIC FLOW.
OTHERWISE...925MB TEMPERATURES PRETTY COOL TODAY REACHING 14-16C
THIS AFTERNOON. THIS SHOULD RESULT IN HIGH TEMPERATURES TOPPING OFF
ONLY IN THE MIDDLE 60S ACROSS NORTH CENTRAL WI...AND LOWER 70S
ELSEWHERE ACROSS THE FORECAST AREA.
HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT WITH CLEAR SKIES/CALM
WINDS/DRY AIRMASS SETTING UP IDEAL RADIATIONAL COOLING. THIS WILL
YIELD CHILLY OVERNIGHT LOWS OF AROUND 40 DEGREES IN THE FAVORED COLD
SPOT AREAS ALONG AND NORTH OF I-94...TO THE 45-50 DEGREE RANGE
ELSEWHERE. THIS SYNOPTIC SCENARIO WILL ALSO SET UP IDEAL RIVER
VALLEY FOG CONDITIONS WITH WIDESPREAD FOG EXPECTED TO FILL THE MAIN
STEM CHANNELS OF THE MISSISSIPPI/WISCONSIN RIVER AND THEIR
TRIBUTARIES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 322 AM CDT MON SEP 2 2013
SURFACE HIGH PRESSURE SLOWLY MOVES SOUTHEAST TUESDAY SETTING UP
LIGHT SOUTH/SOUTHWEST WINDS ACROSS THE AREA. THIS DRAGS IN SLIGHTLY
WARMER AIR INTO THE REGION WITH HIGHS TOPPING OFF IN THE
MIDDLE/UPPER 70S.
NORTHWEST FLOW ALOFT PUSHES A WEAK MID-LEVEL TROUGH/SURFACE COLD
FRONT THROUGH THE AREA WEDNESDAY. THE NAM SEEMS TO BE THE ONLY MODEL
PRODUCING ANY RAINFALL WITH THIS TROUGH/FRONTAL PASSAGE. FOR NOW
WILL KEEP THE FORECAST DRY AS MOST OF THE MOISTURE IS CONFINED ABOVE
700MB AND LOWER LEVELS ARE VERY DRY. HEATING IN ADVANCE OF THE FRONT
SHOULD PUSH HIGHS IN THE LOWER/MIDDLE 80S.
GFS AND ECMWF REMAIN IN GOOD AGREEMENT WITH AN UPPER LEVEL RIDGE
OVER THE INTERMOUNTAIN WEST/HIGH PLAINS...AND NORTHWEST FLOW OVER
THE UPPER MISSISSIPPI RIVER VALLEY REGION THROUGH SATURDAY. THURSDAY/FRIDAY
LOOK DRY WITH SURFACE HIGH PRESSURE THE DOMINANT WEATHER FEATURE.
LOOK FOR HIGHS THURSDAY IN THE UPPER 70/LOWER 80S...WARMING INTO THE
LOWER/MIDDLE 80S ON FRIDAY. NORTHWEST FLOW ALOFT PUSHES ANOTHER WEAK
MID-LEVEL TROUGH/SURFACE COLD FRONT THROUGH ON SATURDAY.
SHOWER/THUNDER CHANCES...ALBEIT SMALL CHANCE...SEEMS TO BE CONFINED
MORE OVER EASTERN WI. DID GO WITH VERY SMALL CHANCES ACROSS OUR
CENTRAL WI COUNTIES ON THE WESTERN FRINGES OF BEST MOISTURE
CONVERGENCE ALONG THE FRONT. HEATING IN ADVANCE OF THIS FRONT
EXPECTED TO PRODUCE HIGHS ON SATURDAY IN THE MIDDLE/UPPER 80S.
BY SUNDAY...APPEARS LOW PRESSURE WILL BEGIN TO BREAK DOWN THE
WESTERN RIDGE WITH EASTERN FRINGES OF MOISTURE TRANSPORT/ISENTROPIC LIFT
REACHING OUR WESTERN AREAS ACROSS NORTH CENTRAL WI INTO SOUTHEAST MN
SEEING A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON.
EXTENDED MODELS ACTUALLY SHOWING A DECENT SHOT AT SOME
SHOWERS/THUNDERSTORMS SUNDAY NIGHT INTO EARLY NEXT WEEK AS LOW
PRESSURE WORKS EAST OUT OF THE PLAINS AND ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1149 PM CDT SUN SEP 1 2013
SURFACE LOW REMAINS JUST TO THE EAST OF LAKE SUPERIOR WITH LARGE
SHIELD OF CLOUDS ON THE BACK SIDE OF THE LOW. CLOUDS CURRENTLY
COVERING NORTHERN WISCONSIN...NORTHEAST MINNESOTA INTO SOUTHERN
ONTARIO AND ARE ADVANCING TO THE SOUTHWEST. THE 02.00 NAM AND
02.03Z RAP CONTINUE THE TREND OF BRINGING THESE CLOUDS INTO THE
AREA OVERNIGHT BUT NOW SUGGEST THEY WILL LINGER LONGER INTO MONDAY
BEFORE MIXING OUT. BASED ON THE SATELLITE TRENDS...WILL BRING IN A
MVFR CEILING TO KLSE AN HOUR OR SO BEFORE IT PUSHES INTO KRST.
WITH BOTH MODELS NOW HANGING ONTO THE MOISTURE LONGER...HELD THE
CEILINGS IN UNTIL 18Z. HIGH PRESSURE WILL THEN BUILD IN FOR THE
REMAINDER OF THE PERIOD ALLOWING SKIES TO CLEAR OUT BY LATE
AFTERNOON/EARLY EVENING WITH WINDS BECOMING LIGHT OUT OF THE NORTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CDT SUN SEP 1 2013
.SHORT TERM...(TONIGHT THROUGH LABOR DAY)
ISSUED AT 215 PM CDT SUN SEP 1 2013
MAIN QUESTION TONIGHT IS CLOUD COVER. CURRENT CLOUD DECK HAS A
COUPLE ELEMENTS TO IT - MAIN MASS IN THE WRAP AROUND REGION WEST OF
AN EASTWARD MOVING SFC LOW...AND DIURNALLY DRIVEN CLOUDS ON THE
SOUTHERN FRINGES OF THIS MASS. THE DIURNAL CLOUD WILL DISSIPATE WITH
SUNDOWN...WHILE THE CLOUDS WITH THE LOW WILL MOVE EAST. HOWEVER...RH
FIELDS POINT TO A SAG SOUTH/SOUTHWEST OF SOME LOW LEVEL SATURATION
AS 925 MB WINDS KICK UP FROM THE NORTH/NORTHEAST AT 20 MPH LATER
TONIGHT. 01.09Z SREF PROBABILITIES ALSO POINT TO A HIGHER LIKELIHOOD
OF LOW CIGS ADVANCING SOUTHEAST...HIGHEST DOWN TO I-94...BUT COULD
WORK TO THE MISSISSIPPI RIVER. WILL INCREASE CLOUDS TONIGHT/EARLY
MONDAY BASED ON THESE TRENDS.
CLOUDS THAT MOVE IN SHOULD EXIT ON MONDAY AS HIGH PRESSURE STARTS TO
BUILD IN FROM THE WEST. THEY MAY NOT BE THAT QUICK TO EXIT NORTH
CENTRAL WI...WHICH COULD BE STUCK IN CLOUDS FOR A BETTER PART OF THE
DAYLIGHT HOURS. A COLD FRONT THAT PASSED ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY TODAY WILL RESULT IN SOME MUCH
COOLER...DRIER AIR WORKING IN FOR LABOR DAY. SREF AND ECMWF 850 TEMP
ANOMALIES ARE AROUND -1 FOR MONDAY. HIGHS COULD STRUGGLE TO REACH 70
IN MANY LOCATIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 215 PM CDT SUN SEP 1 2013
HIGH PRESSURE BUILDS OVERHEAD MONDAY NIGHT...CENTERED OVER THE LOCAL
AREA BY 12Z TUE. LOOKS LIKE A DECENT SETUP FOR FOG IN AREA RIVER
VALLEYS. NAM BUFKIT SOUNDINGS FAVOR IT A BIT MORE THAN THE GFS...BUT
ALL SUGGEST ITS PROBABLE...IF NOT LIKELY. WITH RAIN HAVING BEEN
SPARSE THE PAST COUPLE WEEKS...NOT CONFIDENT THAT FOG WILL DEVELOP
OUTSIDE OF THE RIVER VALLEYS.
GFS AND ECMWF IN GOOD AGREEMENT WITH AN UPPER LEVEL RIDGE TO THE
WEST...AND NORTHWEST FLOW OVER THE UPPER MISSISSIPPI RIVER VALLEY.
SOMEWHAT INACTIVE FLOW...WITH THE MODELS SUGGESTING THAT ANY
PERTURBATION IN THE FLOW WOULD MOVE SOUTH/NORTH OF THE LOCAL
FORECAST AREA. THUS...A CONTINUATION OF THE DRY CONDITIONS.
FOR THE WEEKEND THE RIDGE IS PROGGED TO SHIFT EASTWARD INTO THE
AREA...BUT COULD FLATTEN OUT AS IT DOES...THANKS TO AN UPPER LEVEL
SHORTWAVE TROUGH DRIVING ACROSS THE NORTHERN PLAINS. THIS TROUGH
SHOWS SOME PROMISE OF PCPN CHANCES FOR SUNDAY-MONDAY.
TEMPERATURES WILL GRADUALLY WARM THROUGH THE WEEK...AND COULD BE
FAIRLY WARM FOR THE FIRST WEEKEND OF SEPTEMBER AS WINDS BECOME MORE
SOUTHERLY/RIDGE WORKS IN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1149 PM CDT SUN SEP 1 2013
SURFACE LOW REMAINS JUST TO THE EAST OF LAKE SUPERIOR WITH LARGE
SHIELD OF CLOUDS ON THE BACK SIDE OF THE LOW. CLOUDS CURRENTLY
COVERING NORTHERN WISCONSIN...NORTHEAST MINNESOTA INTO SOUTHERN
ONTARIO AND ARE ADVANCING TO THE SOUTHWEST. THE 02.00 NAM AND
02.03Z RAP CONTINUE THE TREND OF BRINGING THESE CLOUDS INTO THE
AREA OVERNIGHT BUT NOW SUGGEST THEY WILL LINGER LONGER INTO MONDAY
BEFORE MIXING OUT. BASED ON THE SATELLITE TRENDS...WILL BRING IN A
MVFR CEILING TO KLSE AN HOUR OR SO BEFORE IT PUSHES INTO KRST.
WITH BOTH MODELS NOW HANGING ONTO THE MOISTURE LONGER...HELD THE
CEILINGS IN UNTIL 18Z. HIGH PRESSURE WILL THEN BUILD IN FOR THE
REMAINDER OF THE PERIOD ALLOWING SKIES TO CLEAR OUT BY LATE
AFTERNOON/EARLY EVENING WITH WINDS BECOMING LIGHT OUT OF THE NORTH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1037 AM MDT MON SEP 2 2013
.UPDATE...
ISSUED AT 1036 AM MDT MON SEP 2 2013
SOME SHOWERS AND A FEW THUNDERSTORMS CONTINUE AT MID MORNING OVER
CENTRAL WYOMING...INTO CONVERSE COUNTY. THE ACTIVITY SHOULD DEVELOP
OVER THE MOUNTAINS BY MIDDAY AND THEN MOVE TO THE NORTHEAST AND
SPREAD OVER THE REST OF SOUTHEAST WYOMING AND INTO THE PANHANDLE
AS THE AFTERNOON PROGRESSES. SHOWERS AND THUNDERSTORMS SHOULD BE
MORE WIDESPREAD OVER MAINLY SOUTHEAST WYOMING LATER TODAY THAN THE
PAST FEW DAYS. PRECIPITABLE WATER VALUES ARE CURRENTLY BETWEEN
0.75 AND 1.00 INCHES AND WILL INCREASE SLOWLY THIS AFTERNOON. THE
MID AND UPPER LEVEL PLUME OF MOISTURE IS OVER THE WEST HALF OF
WYOMING AT MID MORNING. THE BULK OF THAT MOISTURE WAS AHEAD OF A
SHORTWAVE TROUGH MOVING INTO NORTHERN UTAH. AT 16Z...THE SURFACE
TROUGH WAS ALONG THE LARAMIE RANGE WITH FAVORABLE SURFACE
CONVERGENCE TAKING PLACE. THOSE FACTORS WILL AID CONVECTION FOR
LATER TODAY. FURTHER TO THE EAST...THE ATMOSPHERE IS CURRENTLY
CAPPED. THE CAP MAY BE ERODED LATE THIS AFTERNOON SOME AS
TEMPERATURES...HOWEVER...12Z NAM KEEPS THE CAP IN PLACE OVER THE
EAST PART OF THE PANHANDLE. TEMPERATURES WILL ALSO SHOULD BE
WARMER TODAY AND WELL ABOVE NORMAL. IN A RECENT UPDATE MADE MINOR
CHANGES TO THE FIRST PERIOD OF THE PREVIOUS FORECAST.
UPDATE ISSUED AT 649 AM MDT MON SEP 2 2013
MADE MINOR CHANGES TO POP FORECAST TODAY. A FEW SHOWERS HAVE
POPPED UP OVER NORTHERN CARBON COUNTY THIS MORNING ALONG AN
ELEVATED WARM FRONT. THIS FRONT IS PROJECTED TO MOVE NORTHEASTWARD
TODAY. MODELS PLACE THE FRONT OVER CONVERSE COUNTY LATE THIS
MORNING AND NEAR THE SOUTH DAKOTA/WYOMING BORDER MID AFTERNOON.
NOT SURE IS CONVECTION WILL BE SUSTAINED ALONG THE BOUNDARY.
USUALLY ELEVATED CONVECTION WILL SUBSIDE WITHIN A FEW HOURS AFTER
SUNRISE BUT IN CASE IT DOES NOT...ADDED LOW END POPS TO WESTERN
AND NORTHERN PORTIONS OF THE FORECAST AREA THIS MORNING. UNSTABLE
AIR WITH THIS BOUNDARY LENDS SOME CREDENCE TO THE NAM PRODUCING
QPF INTO THE NORTHERN NEBRASKA PANHANDLE THIS AFTERNOON. ALSO OF
NOTE IS THE 08Z HRRR MODEL RUN KICKS OUT PRECIPITATION OVER THE
SOUTHERN PANHANDLE THIS AFTERNOON. AT ANY RATE IT IS LOOKING LIKE
THERE IS AT LEAST SOME POTENTIAL FOR STORMS OVER THE PANHANDLE
LATER TODAY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 440 AM MDT MON SEP 2 2013
WILL START OFF THIS MORNING UNDER CLEAR SKIES IN THE EAST AND
PARTLY CLOUDY TO THE WEST. CLOUD COVER TO INCREASE BY THIS
AFTERNOON WITH A FEW SHOWERS AND THUNDERSTORM TO DEVELOP. THE MAIN
QUESTION IS COVERAGE AND LOCATION OF THUNDERSTORM ACTIVITY. BEST
CHANCES SHOULD BE IN THE WEST WHERE AS SHORTWAVE SHORTWAVE MOVES
OVER THAT AREA. THE WAVE IS CURRENTLY OVER CENTRAL UTAH MOVING
NORTHWARD. THE MAIN QUESTION FOR CONVECTION TODAY IS THE TRACK THE
WAVE WILL TAKE. MODELS GENERALLY TRACKING THE WAVE INTO NE
WYOMING AND THEN INTO WRN SOUTH DAKOTA BUT THE NAM IS SLIGHTLY
FARTHER SOUTH AND TRIES TO BREAK OUT CONVECTION INTO THE NORTHERN
PANHANDLE LATE THIS AFTERNOON. DID ADD SLIGHT CHANCE POPS TO THE
PANHANDLE BUT CONFIDENCE IS NOT HIGH.
THERE WILL BE NO SHORTAGE OF HEATING IN THE EAST AS SUNNY SKIES
WILL ALLOW FOR MAX HEATING...SO ASSUMING MAX HEATING AND SOME
UPPER LEVEL SUPPORT...A THUNDERSTORM OR TWO IS NOT COMPLETELY OUT
OF THE QUESTION. ALSO THE MODELS ARE SHOWING DUE POINTS IN THE
LOWER 50S FOR THE PANHANDLE THIS AFTERNOON. BASED ON 15 TO 20 KT
800 MB WINDS AND 60 TO 70 DEGREE DEW POINTS CURRENTLY OVER
KANSAS...WOULD NOT BE SURPRISED TO SEE DEW POINTS APPROACHING 60
DEGREES IN THE PANHANDLE BY LATE THIS AFTERNOON. THIS COULD ALSO
LEAD TO A GREATER CHANCE FOR THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING AND WOULD INCREASE SURFACE BASED CAPE VALUES ABOVE THE
500 J/KG THE MODELS ARE SHOWING. EITHER WAY THE SHEAR IS ON THE
WEAK SIDE TODAY SO SEVERE THUNDERSTORM POTENTIAL IS MINIMAL AT
BEST.
TEMPERATURES WILL REBOUND TODAY AS THE UPPER LEVEL RIDGE
REESTABLISHES ITSELF OVER THE ROCKIES. TEMPERATURES TODAY WILL
GENERALLY BE 5 TO 10 DEGREES WARMER THAN YESTERDAY ACROSS THE
PLAINS WITH 90S FOR HIGHS. FARTHER WEST TEMPERATURES WILL MAINLY
BE IN THE 80S OUTSIDE OF THE MOUNTAINS. THE HEAT WILL CONTINUE
TUESDAY AND COULD BE THE WARMEST DAY OF THE WEEK FOR MANY
LOCATIONS. MAY SEE A FEW RECORDS BROKEN AS DRY WEST TO NORTHWEST
DOWN SLOPE FLOW SETS UP IN THE WAVE OF THE DEPARTING SHORTWAVE.
COULD SEE A FEW LOCATIONS IN THE PANHANDLE TOUCH 100 DEGREES.
SLIGHTLY COOLER WEDNESDAY ACROSS THE PLAINS BUT STILL LOOKING AT
WIDESPREAD 80S AND 90S FOR HIGHS. CHANCES FOR PRECIPITATION
TUESDAY AND WEDNESDAY WILL BE MINIMAL WITH CHANCES FOR MEASURABLE
PRECIPITATION MAINLY CONFINED TO THE MOUNTAINS.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 440 AM MDT MON SEP 2 2013
THE UPPER LEVEL RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH
LATE IN THE WEEK...ALTHOUGH WILL BEGIN TO SHIFT EAST AND GIVE WAY
TO SHORTWAVE TROUGHING OVER THE ROCKIES THROUGH THE WEEKEND.
EXPECTING VERY WARM TEMPS ACROSS THE CWA...WITH MARGINAL CHANCES
FOR AFTERNOON SHOWERS AND THUNDERSTORMS. THE BEST CHANCES WILL BE
FOR THE MOUNTAINS AND NEARBY LOWER ELEVATIONS IN THIS FLOW
PATTERN. LEESIDE SFC TROUGH DEVELOPMENT ON THURSDAY WILL MOVE
EASTWARD AS A WARM FRONT ON FRIDAY. THIS COULD FOCUS MORE SHOWER
ACTIVITY FURTHER EAST IN THE LATE AFTERNOON...BUT RIGHT NOW THE
ENVIRONMENT DOES NOT LOOK THAT GREAT FOR MAINTENANCE OF
THUNDERSTORMS WITH LOW BULK SHEAR VALUES PROGGED. A COOL FRONT
LOOKS TO MAKE ITS WAY SOUTH ACROSS THE FORECAST AREA SATURDAY WITH
BLUSTERY NORTHERLY WINDS IN ITS WAKE...TURNING NORTHEAST BY THE
EVENING. TEMPS WILL BE A FEW DEGREES COOLER BEHIND THE FRONT AS
WELL FOR SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1036 AM MDT MON SEP 2 2013
VFR CONDITIONS WILL CONTINUE OVER THE CWA THROUGH THE END OF THE
WEEK. SOME SHOWERS AND THUNDERSTORMS WILL BE OVER SOUTHEAST
WYOMING AND NEARBY PARTS OF THE PANHANDLE THIS AFTERNOON AND
EVENING. SOME OF THOSE STORMS WILL PRODUCE BRIEF WIND GUSTS TO
40 KNOTS AND A PERIOD OF HEAVY RAIN. SOUTH TO SOUTHWEST WINDS WILL
GUST AS HIGH AS 25 KNOTS OVER PARTS OF THE CWA THIS AFTERNOON AND
EARLY EVENING.
&&
.FIRE WEATHER...
ISSUED AT 349 AM MDT MON SEP 2 2013
UPPER LEVEL RIDGE WILL CONTINUE TO BE THE MAIN DRIVER OF WEATHER
CONDITIONS THIS WEEK. HOT DRY CONDITIONS WILL BE THE NORM WITH ONLY
SLIGHT CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS. UPPER LEVEL
RIDGE WILL MAKE FOR LIGHT WINDS THROUGH MOST OF THIS WEEK SO NOT
EXPECTING CRITICAL FIRE WEATHER CONDITIONS. IT WILL BE A BIT
BREEZY OVER SOUTHEAST WYOMING TUESDAY AFTERNOON WITH HUMIDITY VALUES
DIPPING INTO THE 15 TO 25 PERCENT RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...LIEBL
LONG TERM...RJM
AVIATION...WEILAND
FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
700 AM MDT MON SEP 2 2013
.UPDATE...
ISSUED AT 649 AM MDT MON SEP 2 2013
MADE MINOR CHANGES TO POP FORECAST TODAY. A FEW SHOWERS HAVE
POPPED UP OVER NORTHERN CARBON COUNTY THIS MORNING ALONG AN
ELEVATED WARM FRONT. THIS FRONT IS PROJECTED TO MOVE NORTHEASTWARD
TODAY. MODELS PLACE THE FRONT OVER CONVERSE COUNTY LATE THIS
MORNING AND NEAR THE SOUTH DAKOTA/WYOMING BORDER MID AFTERNOON.
NOT SURE IS CONVECTION WILL BE SUSTAINED ALONG THE BOUNDARY.
USUALLY ELEVATED CONVECTION WILL SUBSIDE WITHIN A FEW HOURS AFTER
SUNRISE BUT IN CASE IT DOES NOT...ADDED LOW END POPS TO WESTERN
AND NORTHERN PORTIONS OF THE FORECAST AREA THIS MORNING. UNSTABLE
AIR WITH THIS BOUNDARY LENDS SOME CREDENCE TO THE NAM PRODUCING
QPF INTO THE NORTHERN NEBRASKA PANHANDLE THIS AFTERNOON. ALSO OF
NOTE IS THE 08Z HRRR MODEL RUN KICKS OUT PRECIPITATION OVER THE
SOUTHERN PANHANDLE THIS AFTERNOON. AT ANY RATE IT IS LOOKING LIKE
THERE IS AT LEAST SOME POTENTIAL FOR STORMS OVER THE PANHANDLE
LATER TODAY.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 440 AM MDT MON SEP 2 2013
WILL START OFF THIS MORNING UNDER CLEAR SKIES IN THE EAST AND
PARTLY CLOUDY TO THE WEST. CLOUD COVER TO INCREASE BY THIS
AFTERNOON WITH A FEW SHOWERS AND THUNDERSTORM TO DEVELOP. THE MAIN
QUESTION IS COVERAGE AND LOCATION OF THUNDERSTORM ACTIVITY. BEST
CHANCES SHOULD BE IN THE WEST WHERE AS SHORTWAVE SHORTWAVE MOVES
OVER THAT AREA. THE WAVE IS CURRENTLY OVER CENTRAL UTAH MOVING
NORTHWARD. THE MAIN QUESTION FOR CONVECTION TODAY IS THE TRACK THE
WAVE WILL TAKE. MODELS GENERALLY TRACKING THE WAVE INTO NE
WYOMING AND THEN INTO WRN SOUTH DAKOTA BUT THE NAM IS SLIGHTLY
FARTHER SOUTH AND TRIES TO BREAK OUT CONVECTION INTO THE NORTHERN
PANHANDLE LATE THIS AFTERNOON. DID ADD SLIGHT CHANCE POPS TO THE
PANHANDLE BUT CONFIDENCE IS NOT HIGH.
THERE WILL BE NO SHORTAGE OF HEATING IN THE EAST AS SUNNY SKIES
WILL ALLOW FOR MAX HEATING...SO ASSUMING MAX HEATING AND SOME
UPPER LEVEL SUPPORT...A THUNDERSTORM OR TWO IS NOT COMPLETELY OUT
OF THE QUESTION. ALSO THE MODELS ARE SHOWING DUE POINTS IN THE
LOWER 50S FOR THE PANHANDLE THIS AFTERNOON. BASED ON 15 TO 20 KT
800 MB WINDS AND 60 TO 70 DEGREE DEW POINTS CURRENTLY OVER
KANSAS...WOULD NOT BE SURPRISED TO SEE DEW POINTS APPROACHING 60
DEGREES IN THE PANHANDLE BY LATE THIS AFTERNOON. THIS COULD ALSO
LEAD TO A GREATER CHANCE FOR THUNDERSTORMS LATE THIS AFTERNOON AND
EVENING AND WOULD INCREASE SURFACE BASED CAPE VALUES ABOVE THE
500 J/KG THE MODELS ARE SHOWING. EITHER WAY THE SHEAR IS ON THE
WEAK SIDE TODAY SO SEVERE THUNDERSTORM POTENTIAL IS MINIMAL AT
BEST.
TEMPERATURES WILL REBOUND TODAY AS THE UPPER LEVEL RIDGE
REESTABLISHES ITSELF OVER THE ROCKIES. TEMPERATURES TODAY WILL
GENERALLY BE 5 TO 10 DEGREES WARMER THAN YESTERDAY ACROSS THE
PLAINS WITH 90S FOR HIGHS. FARTHER WEST TEMPERATURES WILL MAINLY
BE IN THE 80S OUTSIDE OF THE MOUNTAINS. THE HEAT WILL CONTINUE
TUESDAY AND COULD BE THE WARMEST DAY OF THE WEEK FOR MANY
LOCATIONS. MAY SEE A FEW RECORDS BROKEN AS DRY WEST TO NORTHWEST
DOWN SLOPE FLOW SETS UP IN THE WAVE OF THE DEPARTING SHORTWAVE.
COULD SEE A FEW LOCATIONS IN THE PANHANDLE TOUCH 100 DEGREES.
SLIGHTLY COOLER WEDNESDAY ACROSS THE PLAINS BUT STILL LOOKING AT
WIDESPREAD 80S AND 90S FOR HIGHS. CHANCES FOR PRECIPITATION
TUESDAY AND WEDNESDAY WILL BE MINIMAL WITH CHANCES FOR MEASURABLE
PRECIPITATION MAINLY CONFINED TO THE MOUNTAINS.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 440 AM MDT MON SEP 2 2013
THE UPPER LEVEL RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH
LATE IN THE WEEK...ALTHOUGH WILL BEGIN TO SHIFT EAST AND GIVE WAY
TO SHORTWAVE TROUGHING OVER THE ROCKIES THROUGH THE WEEKEND.
EXPECTING VERY WARM TEMPS ACROSS THE CWA...WITH MARGINAL CHANCES
FOR AFTERNOON SHOWERS AND THUNDERSTORMS. THE BEST CHANCES WILL BE
FOR THE MOUNTAINS AND NEARBY LOWER ELEVATIONS IN THIS FLOW
PATTERN. LEESIDE SFC TROUGH DEVELOPMENT ON THURSDAY WILL MOVE
EASTWARD AS A WARM FRONT ON FRIDAY. THIS COULD FOCUS MORE SHOWER
ACTIVITY FURTHER EAST IN THE LATE AFTERNOON...BUT RIGHT NOW THE
ENVIRONMENT DOES NOT LOOK THAT GREAT FOR MAINTENANCE OF
THUNDERSTORMS WITH LOW BULK SHEAR VALUES PROGGED. A COOL FRONT
LOOKS TO MAKE ITS WAY SOUTH ACROSS THE FORECAST AREA SATURDAY WITH
BLUSTERY NORTHERLY WINDS IN ITS WAKE...TURNING NORTHEAST BY THE
EVENING. TEMPS WILL BE A FEW DEGREES COOLER BEHIND THE FRONT AS
WELL FOR SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 0615 AM MDT MON SEP 2 2013
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH THE MAIN
CONCERN FOR TODAYS CONVECTION GUSTY WINDS FROM THESE HIGH BASED
STORMS. BREEZY SOUTHERLY WINDS WILL PREVAIL THROUGH THE EARLY
EVENING AT MOST PLACES...AND WILL DIMINISH THROUGH THE OVERNIGHT
PERIOD. THE EXCEPTION WILL BE IN THE PANHANDLE WHERE SOUTH WINDS
THIS EVENING WILL REMAIN ON THE GUSTY SIDE THROUGH THE EARLY
MORNING HOURS. THUNDERSTORMS THAT ROLL ACROSS THE TERMINALS TODAY
WILL BRING BRIEF MVFR CONDITIONS AND GUSTY ERRATIC WINDS.
.FIRE WEATHER...
ISSUED AT 349 AM MDT MON SEP 2 2013
UPPER LEVEL RIDGE WILL CONTINUE TO BE THE MAIN DRIVER OF WEATHER
CONDITIONS THIS WEEK. HOT DRY CONDITIONS WILL BE THE NORM WITH ONLY
SLIGHT CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS. UPPER LEVEL
RIDGE WILL MAKE FOR LIGHT WINDS THROUGH MOST OF THIS WEEK SO NOT
EXPECTING CRITICAL FIRE WEATHER CONDITIONS. IT WILL BE A BIT
BREEZY OVER SOUTHEAST WYOMING TUESDAY AFTERNOON WITH HUMIDITY VALUES
DIPPING INTO THE 15 TO 25 PERCENT RANGE.
&&
.FIRE WEATHER...
ISSUED AT 349 AM MDT MON SEP 2 2013
UPPER LEVEL RIDGE WILL CONTINUE TO BE THE MAIN DRIVER OF WEATHER
CONDITIONS THIS WEEK. HOT DRY CONDITIONS WILL BE THE NORM WITH ONLY
SLIGHT CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS. UPPER LEVEL
RIDGE WILL MAKE FOR LIGHT WINDS THROUGH MOST OF THIS WEEK SO NOT
EXPECTING CRITICAL FIRE WEATHER CONDITIONS. IT WILL BE A BIT
BREEZY OVER SOUTHEAST WYOMING TUESDAY AFTERNOON WITH HUMIDITY VALUES
DIPPING INTO THE 15 TO 25 PERCENT RANGE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...LIEBL
SHORT TERM...LIEBL
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS DULUTH MN
350 AM CDT WED SEP 4 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 349 AM CDT WED SEP 4 2013
AT 345AM/0845Z...A COLD FRONT STRETCHED FROM EAST TO WEST ACROSS
LAKE SUPERIOR...NORTHERN MINNESOTA...AND SOUTHEASTERN NORTH
DAKOTA. STRONG SURFACE HIGH PRESSURE WAS CENTERED NEAR SOUTHERN
MANITOBA. A LARGE MID/UPPER LEVEL RIDGE WAS CENTERED NEAR
COLORADO/KANSAS WITH THE AXIS EXTENDING NORTH TO CENTRAL MONTANA
AND INTO WESTERN CANADA. MUCH OF THE NORTHLAND HAD LIGHT TO NEARLY
CALM WINDS...BUT 5 TO 10 KNOT NORTHERLY WINDS WERE DEVELOPING
ACROSS FAR NORTHERN MINNESOTA IN THE WAKE OF THE COLD FRONT.
TEMPERATURES RANGED FROM THE MID 50S TO MID 60S...WITH MOST OF THE
NORTHLAND IN THE UPPER 50S AND LOWER 60S. THERE WERE INCREASING
PATCHES OF BKN/OVC LOW LEVEL CLOUDS ACROSS THE EASTERN AND
SOUTHERN FORECAST AREAS...ESPECIALLY OVER THE ARROWHEAD AND LAKE
SUPERIOR.
EARLY THIS MORNING...THE COLD FRONT WILL CONTINUE MOVING SOUTH
THROUGH THE NORTHLAND. BASED ON THE HRRR AND RAP...IT APPEARS
THERE WILL BE INCREASING CLOUD COVER OVER LAKE SUPERIOR AND PARTS
OF THE SOUTHERN FORECAST AREA IN THE WAKE OF THE COLD FRONT. IN
THE CASE OF LAKE SUPERIOR AND NW WISCONSIN...THIS IS LIKELY DUE TO
THE ADDED MOISTURE THE INCREASING NORTHERLY WINDS WILL PROVIDE
FROM LAKE SUPERIOR. I RAISED THE MORNING LOW TEMPERATURES A BIT
BECAUSE THE LIGHT WINDS ACROSS THE NORTHLAND AND THE MOISTURE
COMPRESSION NEAR THE FRONT SEEM TO BE PREVENTING THE TEMPERATURES
FROM FALLING MUCH THIS MORNING.
TODAY...THE SURFACE HIGH PRESSURE IN SOUTHERN MANITOBA WILL MOVE
OVER NORTHERN MINNESOTA. THIS SHOULD PROVIDE MOSTLY TO PARTLY
SUNNY SKIES FOR THE NORTHLAND AFTER THE LINGERING MORNING BKN/OVC
LOW LEVEL CLOUDS DISSIPATE. THERE MAY BE SOME MID/HIGH LEVEL
CLOUDS ACROSS THE SOUTHERN AND WESTERN FORECAST AREA AS THE MODELS
SHOW SOME SATURATION ALOFT ALONG SOME WEAK CHANNELED VORTICITY
STRETCHING FROM THE UPPER MIDWEST TO SOUTH CENTRAL CANADA ON THE
EASTERN SIDE OF A MID/UPPER LEVEL RIDGE. HIGH TEMPERATURES SHOULD
RANGE THE MID 60S TO MID 70S WITH THE COOLER TEMPERATURES ACROSS
NORTHERN MINNESOTA.
TONIGHT...THE SURFACE HIGH PRESSURE WILL BEGIN TO SHIFT TOWARD
NORTHERN WISCONSIN AND LAKE MICHIGAN. THE NORTHLAND CAN EXPECT
CLEAR TO MOSTLY CLEAR SKIES AND LIGHT TO CALM WINDS. THE COLD
FRONT WILL USHER IN LOW DEW POINT TEMPERATURES...AND THIS COMBINED
WITH THE LACK OF WINDS AND CLOUDS...WILL ALLOW TEMPERATURES TO
DROP QUITE A BIT. MUCH OF INLAND NORTHERN MINNESOTA AND PARTS OF
INLAND NW WISCONSIN SHOULD SEE TEMPERATURES DROP TO THE UPPER 30S
AND LOW 40S. THIS MEANS SOME AREAS COULD SEE FROST AND WE WILL
NEED TO CONSIDER THE NEED FOR A FROST ADVISORY. HOWEVER...THE MOST
RECENT MODELS SHOW SLIGHTLY HIGHER DEW POINT
TEMPERATURES...ESPECIALLY OVER NW WISCONSIN...COMPARED TO THE
PREVIOUS FORECAST. ALSO...I SLIGHTLY RAISED TEMPERATURES. I AM NOT
CONFIDENT OF ANY WIDESPREAD FROST...SO I KICK THE CAN TO THE DAY
SHIFT TO MAKE A FINAL DECISION ON A FROST ADVISORY. THE MOST
LIKELY AREA FOR FROST IS ACROSS THE IRON RANGE AND THE INTERIOR
ARROWHEAD.
THURSDAY...THE SURFACE HIGH PRESSURE WILL SHIFT EAST TO THE
MICHIGAN AND THE EASTERN GREAT LAKES. LIGHT SOUTHERLY FLOW OVER
THE NORTHLAND AND SUNNY SKIES WILL PROVIDE A WARMER DAY WITH
TEMPERATURES REACHING THE UPPER 60S TO UPPER 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 349 AM CDT WED SEP 4 2013
THURSDAY NIGHT OUR SURFACE RIDGE SLIPS OFF TO THE SOUTHEAST
AGAIN...WITH SOUTHWEST FLOW BEGINNING AGAIN OVER THE FORECAST
AREA. THIS SHOULD KEEP OUR TEMPERATURES UP IN THE 50S OVERNIGHT.
A SHORTWAVE DIVING THROUGH THE NORTHWEST UPPER LEVEL FLOW MAY
BRING A FEW SHOWERS AND THUNDERSTORMS TO THE AREA OVERNIGHT...BUT
THIS WILL BE LIMITED TO THE FAR NORTHERN SECTIONS OF THE AREA. WE
ARE JUST GOING TO GET A GLANCING BLOW...SO HAVE KEPT POPS IN THE
SLIGHT CHANCE CATEGORY BOTH THURSDAY NIGHT AND FRIDAY. HIGHS
FRIDAY TO BE WARM AS WELL...IN THE LOW TO MID 80S.
FRIDAY NIGHT THROUGH SATURDAY TO BE ACTIVE WITH A FEW MORE
SHORTWAVE OVERTOPPING THE UPPER LEVEL RIDGE OVER THE ROCKIES...AND
A COLD FRONT DROPS THROUGH THE AREA FRIDAY NIGHT AND SATURDAY AS
WELL. HAVE SOME SLIGHT CHANCE AND CHANCE POPS GOING...WHICH MAY BE
RAISED AS DETAILS BECOME CLEAR. WARM TEMPERATURES ARE EXPECTED TO
CONTINUE. SATURDAY NIGHT SHOULD BE QUIET AND DRIER.
BEGINNING SUNDAY UNCERTAINTY INCREASES OVER THE AREA WITH THE
UPPER LEVEL RIDGE FLATTENING AND SHIFTING EAST...ALLOWING A
FAIRLY STRONG SHORTWAVE TO MOVE ACROSS THE AREA IN THE TUESDAY-
WEDNESDAY TIME RANGE. MODELS HAVE VARYING SOLUTIONS...BUT
GENERALLY TEMPERATURES COOL OFF BACK TOWARDS NORMAL VALUES
AGAIN...WITH PRECIPITATION CHANCES BEGINNING SUNDAY AND CONTINUING
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1233 AM CDT WED SEP 4 2013
WEAK SFC FRONT WILL BE CROSSING THE REGION EARLY TONIGHT FROM
NORTH TO SOUTH AND ALLOWING WINDS TO SHIFT TO THE NORTH AND BECOME
AROUND 3-5 KTS STRONGER. COULD SEE A VERY BRIEF PERIOD OF LLWS
ALONG THE FRONT AT DLH AND HYR UNTIL AROUND 08/09Z. CLOUDS WILL
ALSO INCREASE ALONG THE FRONT...MAINLY STAYING VFR...WITH THE
EXCEPTION OF AROUND HIB...DLH AND HYR WHERE A PERIOD OF MVFR CIGS
ARE POSSIBLE DUE TO WEAK LAKE ENHANCEMENT AS NORTH WINDS PUSH
INLAND FROM LS. HIGH PRESSURE WILL BUILD IN QUICKLY WED
AFTERNOON/EVENING AND ALLOW SKIES TO CLEAR OUT AND WINDS TO BECOME
CALM.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT THIS MORNING FOR LSZ121-
144>148.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
345 AM EDT WED SEP 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE OHIO VALLEY TODAY. ON
THURSDAY...A MOISTURE-STARVED COLD FRONT WILL MOVE SOUTH THROUGH THE
REGION...PRODUCING NO PRECIPITATION. ANOTHER AREA OF HIGH PRESSURE
WILL MOVE IN BEHIND THE FRONT...WITH TEMPERATURES REMAINING SLIGHTLY
COOLER THAN NORMAL FOR FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL MAINTAIN ITS CONTROL OVER THE WEATHER
TODAY...WITH VERY TRANQUIL CONDITIONS EXPECTED. RH THROUGH THE
COLUMN IS VERY LOW (ESPECIALLY AROUND 850MB...ABOUT 10 PERCENT).
THE SKY GRIDS HAVE BEEN KEPT IN THE SUNNY CATEGORY...THOUGH THERE
MAY BE VERY ISOLATED WEAK CUMULUS DEVELOPMENT...OR A FEW PATCHES
OF VERY THIN CIRRUS.
ALTHOUGH FULL SUN IS EXPECTED...MIXING MAY BE SOMEWHAT LIMITED
WITH THE LIGHT WINDS...AND MODEL SOUNDINGS INDICATE MAKING IT UP
TO ABOUT 870MB-860MB. THERE IS SOME WARM ADVECTION EXPECTED TO
OCCUR ALOFT (WNW FLOW OUT OF THE BIG RIDGE TO THE WEST)...SO TEMPS
SHOULD CLIMB A FEW DEGREES FROM YESTERDAY.
JUMPING BACK TO THE VERY NEAR-TERM...THERE DOES APPEAR TO BE SOME
FOG POTENTIAL EARLY THIS MORNING. TEMPERATURES RE RADIATING
SIGNIFICANTLY AND RIVER VALLEYS ARE ALREADY BEGINNING TO FILL IN
WITH LOWERED VISIBILITIES. IN ADDITION...THE HRRR DEPICTS A VERY
LARGE AREA OF DENSE FOG DEVELOPING OVER NORTHERN INDIANA. NONE OF
THIS ADDS UP TO WIDESPREAD SIGNIFICANT FOG OVER THE ILN CWA...BUT
SOME PATCHY FOG HAS BEEN INCLUDED IN THE NORTHWEST CWA AND IN THE
RIVER VALLEYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THE SHORT TERM OF THE FORECAST WILL BEGIN WITH THE CWA JUST AHEAD
OF A COLD FRONT MOVING IN FROM THE NORTH...AS THE WEDNESDAY HIGH
PRESSURE SHUNTS WESTWARD AND WEAKENS. THE FRONT IN QUESTION WILL
BE FAR REMOVED FROM ITS SOURCE IN A MID-LEVEL TROUGH CROSSING EAST
OF JAMES BAY. THE FRONT WILL BE MOVING INTO THE VERY DRY AIR MASS
OVER THE OHIO VALLEY. THE MODEL CONSENSUS ON LOW AND MID LEVEL RH
HAS COME UP SLIGHTLY FROM YESTERDAY...BUT THERE IS STILL LITTLE
TO INDICATE THAT MEASURABLE PRECIPITATION WILL OCCUR. AT
MOST...SOME SPRINKLES OR VERY LIGHT SHOWERS MAY BE POSSIBLE...BUT
THIS WILL NOT BE INCLUDED IN THE FORECAST. THE FRONT WILL BE
ACCOMPANIED BY A MARKED NNE WIND SHIFT...WITH A MASSIVE AMOUNT OF
NEGATIVE THETA-E ADVECTION. A NNE-TO-SSW GRADIENT HAS BEEN USED
FOR THE MAX TEMP GRIDS ON THURSDAY...ACCOUNTING FOR THE
FRONT...THOUGH THE TIMING OF THE TEMPERATURE CURVE STILL APPEARS
GENERALLY DIURNAL.
AFTER THE FRONT CROSSES THROUGH ON THURSDAY...HIGH PRESSURE IS
EXPECTED TO BUILD IN FROM THE NORTH ON THURSDAY NIGHT AND FRIDAY.
ALTHOUGH WINDS MAY NOT GO COMPLETELY CALM THURSDAY NIGHT...THE AIR
MASS WILL BE DRYING AND CAPABLE OF SOME RATHER COOL TEMPERATURES
(LOWER 50S AND UPPER 40S). THE ADVECTION PATTERN WILL REMAIN
NEUTRAL TO SLIGHTLY COOL ON FRIDAY...WITH THE OVERALL AIR MASS NOT
MODIFYING MUCH FROM THE COOL STARTING POINT. SO...DESPITE QUITE A
BIT OF SUN EXPECTED...MAX TEMPS WILL NOT BE ESPECIALLY HIGH (MID
70S IN CENTRAL OHIO TO AROUND 80 IN THE SW). THIS IS WARMER THAN
THE NAM BUT NOT AS WARM AS GFS/ECMWF 850MB TEMPS WOULD OTHERWISE
SUPPORT.
THE SURFACE HIGH WILL BE MOVING EAST OF THE REGION BY
SATURDAY...AS RIDGING BEGINS TO BUILD IN ALOFT. THIS WILL PUT THE
CWA IN A REGIME OF NORTHWEST FLOW ALOFT (EVENTUALLY SPILLING IN
SOME CLOUDS) AND SW FLOW AT THE SURFACE (WITH TEMPERATURES AND
DEWPOINTS BEGINNING TO RISE AGAIN).
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
STARTING ON SATURDAY...SHORT WAVE ENERGY ROUNDING THE CREST OF
THE UPPER RIDGE WILL COMBINE WITH LIMITED SURFACE CONVERGENCE AND
MODERATE INSTABILITY TO PRODUCE A CHANCE OF THUNDERSTORMS FROM
TIME TO TIME. THE BEST CHANCE APPEARS TO BE ON SUNDAY...WHEN A
FRONTAL BOUNDARY SAGGING FROM THE NORTH MAY BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT. WITH NO STRONG FORCING INDICATED FOR THE
REST OF THE PERIOD...KEPT POPS UNDER THE 25 PERCENT THRESHOLD
REQUIRED TO SHOW UP IN THE FORECAST.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
THE GREAT LAKES AND THE OHIO VALLEY WILL REMAIN UNDER A NORTHWEST
FLOW PATTERN ALOFT THROUGH THE TAF PERIOD. AT THE SURFACE...HIGH
PRESSURE ORIENTED OVER THE OHIO VALLEY WILL MOVE SOUTH OF THE
RIVER BY TONIGHT AS A WEAK COLD FRONT PUSHES IN FROM THE NORTH.
THE FRONT SHOULD BE SOUTH OF THE RIVER NEAR OR AFTER 12Z THURSDAY.
THE FRONT IS MOISTURE STARVED...SO ONLY A MIX OF HIGH CLOUDS AND
SOME STRATOCUMULUS CLOUDS ARE EXPECTED.
IN THE MEANTIME...MAINLY CLEAR SKIES WILL DOMINATE THROUGH THE
REMAINDER OF THE MORNING HOURS AND INTO THE DAYTIME. SOME RIVER
VALLEY FOG IS EXPECTED TO DEVELOP AT KLUK. AM EXPECTING THIS TO BE
FAIRLY SHALLOW...AND WITH THE LACK OF ANY STEERING FLOW FROM THE
EAST OR SOUTHEAST...THE FOG SHOULD RESULT IN CONSIDERABLE
VISIBILITY FLUCTUATIONS. HAVE GONE WITH IFR VSBYS BY 08Z WITH SOME
VLIFR CONDITIONS BETWEEN 09Z AND 12Z. ELSEWHERE SOME MVFR VSBYS
WILL LIKELY DEVELOP AT THE MORE RURAL AIRPORTS OF KILN AND KLCK.
KLCK MAY EVEN EXPERIENCE SOME BRIEF IFR VSBYS TOWARD MORNING. ALL
FOG/MIST SHOULD QUICKLY DISSIPATE BETWEEN 12Z AND 14Z.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
338 AM CDT WED SEP 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CDT WED SEP 4 2013
CURRENTLY SEEING SOME SCATTERED SHOWERS AND A FEW THUNDERSTORMS
ACROSS SOUTH CENTRAL SOUTH DAKOTA. IN GENERAL EXPECT THE COVERAGE OF
THESE SHOWERS TO DECREASE DURING THE MORNING AS WE LOSE THE LOW
LEVEL JET. HOWEVER...A WEAK MID LEVEL WAVE WILL REMAIN IN THE AREA
THROUGH THE DAY...WITH DECENT MID LEVEL MOISTURE AND SOME THETAE
ADVECTION. THUS WILL KEEP SLIGHT CHANCE POPS THROUGH THE
DAY...MAINLY FROM JUST EAST OF THE INTERSTATE 29 CORRIDOR AND POINTS
WEST. DRY AIR IN THE LOWER LEVELS SHOULD MAKE IT TOUGH FOR MUCH OF
THIS MID LEVEL ACTIVITY TO REACH THE GROUND...BUT DO THINK A FEW
SHOWERS ARE POSSIBLE. THE HRRR IS MOST AGGRESSIVE WITH THE
ACTIVITY...AND WHILE IT SEEMS OVERDONE...IT DOES GIVE ANOTHER REASON
TO KEEP THE SLIGHT CHANCE POPS. INSTABILITY IS MARGINAL...BUT GIVEN
THE HIGH BASED NATURE OF THESE STORMS THERE MAY BE JUST ENOUGH TO
GET A LIGHTNING STRIKE OR TWO WITH THE SHOWERS EVERY ONCE IN A
WHILE...SO KEPT THUNDER IN FOR NOW. HIGH TEMPERATURES TODAY SHOULD
BE IN THE 80S...WITH THE CLOUD COVER PREVENTING FULL HEATING FOR
MOST OF THE AREA. MUCH OF THE SAME TONIGHT...WITH THE MID LEVEL WAVE
IN THE VICINITY...EXPECTING A MOSTLY CLOUDY NIGHT. COULD SEE A
SLIGHT UPTICK IN SHOWER ACTIVITY THE FIRST PORTION OF THE NIGHT AS
THE LOW LEVEL JET GETS GOING...BUT NOT REAL CONFIDENT IN THAT. THUS
WILL KEEP JUST SLIGHT CHANCE POPS FOR NOW. EITHER WAY NOT EXPECTING
MUCH. DID RAISE LOWS SOME WITH THE NEWER GUIDANCE COMING IN A BIT
WARMER...SUGGESTING ANY COOLER AND DRYER LOW LEVEL AIR STAYS
NORTHEAST OF THE CWA. GENERALLY LOOKING FOR LOW TO MID 60S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 4 2013
AN UPPER LEVEL WAVE AND A WEAK MID LEVEL BOUNDARY COULD SPARK A FEW
SHOWERS OVER THE FAR EASTERN CWA ON THURSDAY BUT WITH FAIRLY DRY LOW
LEVELS AND WEAK MID LEVEL INSTABILITY NO PLAN TO ADD ANY POPS AS
WHATEVER COULD DEVELOP WOULD REMAIN ON THE LIGHT SIDE. AS THE WAVE
EXITS WILL BE A BIT OF A EASTERLY COMPONENT TO THE WIND SO WHILE THE
DAY WILL BE WARM EXPECT NO MAJOR MIXING. HIGHS MAINLY IN THE LOWER
TO MID 80S.
THURSDAY NIGHT INTO FRIDAY WILL SEE A TIGHTENING OF THE GRADIENT AND
AN INCREASE IN THE LOW LEVEL TEMPERATURE FIELD. THIS WILL LEAD
TOWARDS WARM LOWS IN THE MID AND UPPER 60S AND HIGHS ON FRIDAY WELL
INTO THE 90S WITH SOMETHING AROUND 100 POSSIBLE IN CENTRAL SOUTH
DAKOTA.
A STRONG RIDGE OF HIGH PRESSURE WILL BE IN PLACE FOR MUCH OF THE
PERIOD...THEN SOME HINTS THAT IT SHOULD BREAK DOWN A BIT EARLY NEXT
WEEK AS A WEAK SHORTWAVE MOVES THROUGH THE NORTHERN ROCKIES AND INTO
THE NORTHERN PLAINS. OVERALL THE MODELS ARE IN PRETTY GOOD AGREEMENT
WHICH SUGGESTS VERY WARM READINGS SATURDAY THROUGH MONDAY...WITH THE
HOTTEST TEMPERATURES LIKE FRIDAY AND SATURDAY AHEAD OF A WEAK
BOUNDARY THAT IS PROGGED TO LEAK SOUTHWARD INTO THE AREA. NOT MUCH
PUNCH FROM THIS BOUNDARY AS THE WAVE THAT IS FORCING IT SOUTH IS
MOVING SOUTHEAST THROUGH THE GREAT LAKES REGION. THE RIDGE
REESTABLISHES AGAIN ON MONDAY AS THE WEAK WAVE MOVES ONTO THE PLAINS
AND TRIES TO BRING A BOUNDARY INTO THE AREA ON TUESDAY. IF THIS WAVE
IS A LITTLE SLOWER TUESDAY COULD PROVE TO BE VERY WARM AS WELL. WILL
CONFINE POPS TO THE TIMING OF THE TWO FRONTS WHICH SHOULD MAINLY BE
SATURDAY NIGHT INTO SUNDAY AND MONDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1017 PM CDT TUE SEP 3 2013
MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD. THERE WILL BE A
POSSIBILITY OF SCATTERED SHOWERS AND THUNDERSTORMS THROUGH SOUTH
CENTRAL SOUTH DAKOTA...LOWER JAMES RIVER VALLEY...AND INTO THE
MISSOURI RIVER VALLEY FOR TONIGHT AND TOMORROW. THE MAJORITY OF
THIS ACTIVITY IS EXPECTED TO REMAIN WEST OF THE TAF SITES...SO DID
NOT INCLUDE IN THE TAFS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JM
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1113 PM MDT TUE SEP 3 2013
.UPDATE...
ISSUED AT 742 PM MDT TUE SEP 3 2013
00Z KUNR SOUNDING SHOWS MLCIN. LATEST CONVECTIVE ALLOWING MODELS
SHOW LITTLE IN THE WAY OF SHRA/TSRA OVERNIGHT. UPSTREAM WAVES OVER
WESTERN WY WILL HAVE LITTLE MUCAPE TO WORK WITH OVERNIGHT. DIURNAL
LESSENING OF INSTABILITY NOTED ON MESOANALYSIS PRODUCTS. WILL
REDUCE POPS WITH UPDATE FOR ENTIRE CWA AND LEAVE A SMALL ARC OF 15
POPS FROM SOUTHEAST MT INTO SOUTH CENTRAL SD.
&&
.SHORT TERM...THIS EVENING THROUGH WEDNESDAY NIGHT
ISSUED AT 234 PM MDT TUE SEP 3 2013
WATER VAPOR IMAGERY HAS THE UPPER RIDGE BUILDING FROM THE ROCKIES
INTO THE PLAINS. SEVERAL SHORTWAVES ARE MOVING THROUGH THE RIDGE
WITH ONE OVER CENTRAL SOUTH DAKOTA...TWO SMALL WAVES IN WESTERN AND
CENTRAL WYOMING...AND A LARGER WAVE NEAR SALT LAKE CITY. RADAR HAS
CONVECTION EXTENDING THROUGH CENTRAL SOUTH DAKOTA...WITH NOT MUCH
HAPPENING OVER WYOMING WITH THE SMALLER WAVES. VISIBLE SATELLITE IS
SHOWING SOME CU DEVELOPING OVER THE BLACK HILLS...PARTS OF
NORTHEASTERN WYOMING AND SOUTHWEST SOUTH DAKOTA. AT THE SURFACE...AN
AREA OF LOW PRESSURE IS LOCATED OVER SOUTHWESTERN SOUTH DAKOTA WITH
A WARM FRONT EXTENDING THROUGH SOUTH CENTRAL SOUTH DAKOTA AND A LEE
TROF THROUGH THE BLACK HILLS AND EASTERN MONTANA.
FOR TONIGHT...NOT CONFIDENT IN THE PLACEMENT OF CONVECTION WITH THE
HRRR AND RAP MODELS SHOWING LITTLE IF ANY CONVECTION AND LESS MLCAPE
THAN THE NAM OR GFS. EXPECT SOME CONVECTION WILL FIRE DUE TO DIURNAL
HEATING...HOWEVER SHEAR IS NOT OVERLY IMPRESSIVE FOR SEVERE
POTENTIAL. MAIN CONCERN WITH ANY STORM THAT DEVELOPS TONIGHT WILL BE
HEAVY RAIN POTENTIAL. PWS ARE 200 PERCENT OF NORMAL WITH STORM
MOVEMENT AROUND 15KTS. HOWEVER WITH MY LACK OF CONFIDENCE ON STORM
DEVELOPMENT AND PLACEMENT HAVE DECIDED TO FORGO ANY TYPE OF HYDRO
HEADLINES AT THIS TIME.
ON WEDNESDAY/WEDNESDAY NIGHT...UPPER RIDGE SHOULD AMPLIFY FURTHER
INTO THE NORTHERN PLAINS. HOWEVER...TEMPS WILL BE FEW DEGREES COOLER
AS SURFACE LOW SHIFTS INTO EASTERN COLORADO AND PULLS IN SLIGHTLY
COOLER AIR FROM THE NORTH. BEST CHANCE FOR ANY CONVECTION WILL BE
ACROSS THE FAR WESTERN ZONES NEAR THE INVERTED TROF EXTENDING NORTH
FROM THE SURFACE LOW OVER EASTERN COLORADO AND POSSIBLY IN SOUTH
CENTRAL SOUTH DAKOTA WITH THE WARM FRONT EXTENDING THROUGH NORTHERN
NEBRASKA.
&&
.LONG TERM...THURSDAY THROUGH TUESDAY
ISSUED AT 234 PM MDT TUE SEP 3 2013
LONG WAVE RIDGE OVER CWA WITH A LONG WAVE TROF OVER THE LOWER GREAT
LAKES AND JUST OFF THE WEST COAST. GFS AND ECMWF SHOW PROGRESSION
OF STRONG SHORT WAVE OUT OF THE WEST COAST TROF TO ERN MT BY 12Z
MON AS LONG WAVE RIDGE UNDERGOES FLATTENING AND DISCONTINUOUS
RETROGRESSION TO 135W BY 12Z MON. RIDGE THEN AMPLIFIES AND MOVES
SLOWLY E WARD DURING MID WEEK.
THIS EVOLUTION ALLOWS SIGNIFICANT SURGE OF COOLER AIR FOLLOWING E
WARD MOVEMENT OF SHORT WAVE TROF AND A RETURN TO MORE SEASONAL
TEMPERATURES TUES. THE COLD FRONT AND UPPER SUPPORT LEADING THIS
SURGE WILL LIKELY RESULT IN SHOWERS AND TSTMS REFLECTED IN HIGHER
POPS SATURDAY INTO MONDAY.
STAYED QUITE CLOSE TO GUIDANCE WITH TEMPERATURES THROUGH THE
EXTENDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1111 PM MDT TUE SEP 3 2013
ISOLATED SHRA/TSRA MAY OCCUR FROM ABOUT K2WX TO KPHP TO KICR
OVERNIGHT...POSSIBLY LINGERING INTO SOUTH CENTRAL SD EARLY
WEDNESDAY MORNING. ADDITIONAL TSRA MAY DEVELOP OVER NORTHEAST
WY/FAR WESTERN SD WEDNESDAY AFTERNOON/EVENING. OTHERWISE VFR
CONDITIONS WILL CONTINUE THROUGH THE PERIOD.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...MLS
LONG TERM...BARBER
AVIATION...HELGESON
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE
.SYNOPSIS...
ISSUED AT 339 AM CDT WED SEP 4 2013
DRY WITH SEASONABLE TEMPERATURES EARLY...THEN BECOME WARMER AND
MORE HUMID AGAIN THIS WEEKEND AND EARLY NEXT WEEK.
THE MAIN BAND OF WESTERLIES WAS ACRS CANADA...AND WL REMAIN SO
THROUGHOUT THE PERIOD. WITHIN IT...LNGWV RIDGE POSN WL BE OVER WRN
CANADA...WITH A TROF IN THE E. A SHOT OF COLD AIR FM NRN CANADA WL
LEAD TO SOME AMPLIFICATION OF THE ERN TROF EARLY...THEN THE TEND
SHOULD BE FOR A GRADUAL FLATTENING OF THE FLOW. MEANWHILE ACRS THE
CONUS...THE LARGE SCALE WL BE DOMINATED BY SPRAWLING ANTICYCLONE
CURRENTLY CENTERED OVER THE CEN/SRN ROCKIES AND HIGH PLAINS. A
CLOSED UPR LOW OFF THE PAC NW COAST WL EVENTUALLY START TO WORK
ITS WAY E. THAT WL PROBABLY CAUSE THE UPR HIGH TO SHIFT E TOWARD
THE MISSISSIPPI VALLEY LATE IN THE WEEKEND AND NEXT WEEK.
OVERALL...THIS IS A PRETTY TYPICAL UPR PATTERN FOR EARLY AUTUMN.
THE NWLY UPR FLOW ALONG THE SRN EDGE OF THE WESTERLIES WL BE STG
ENOUGH TO SUPPRESS THE VERY WARM/HUMID AIR S OF THE FCST AREA FOR
THE FIRST PART OF THE FCST PERIOD...BUT AS THE FLOW DEAMPLIFIES
AND THE UPR HIGH SHIFTS E...SOME HEAT AND HUMIDITY WL PROBABLY
RETURN TO THE AREA. THE TEMPERATURE ROLLER COASTER WL CONT AT THE
START OF THE FCST PERIOD...WITH WARMER AIR ACRS THE AREA TDA
REPLACED BY COOLER CONDITIONS FOR THE NEXT COUPLE DAYS. THEN TEMPS
SHOULD HEAD BACK TO ABV NORMAL LEVELS BY THE WEEKEND AND WL
PROBABLY STAY THERE NEXT WK. HUMIDITIES WL ALSO BE ON THE
INCREASE. DRY WX WL CONT FOR A FEW MORE DAYS...THEN PCPN CHCS WL
RETURN ONCE THE HEAT AND HUMIDITIY DOES.
&&
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 339 AM CDT WED SEP 4 2013
OVERALLY A PRETTY QUIET PERIOD...THOUGH LOTS OF FCST DETAILS TO
SORT OUT. WELL DEFINED COLD FRONT WAS SURGING SWD ACRS THE LAKE
SUPERIOR RGN EARLY THIS MORNING. WAA/MIXING WITH TIGHTENING
PRESSURE GRADIENT WAS CAUSING TEMPS TO RISE AHEAD OF THE FRONT
DESPITE IT BEING NIGHTTIME...WITH SXHW3 ACTUALLY UP TO 72 F AT ONE
POINT. MODELS WERE TURNING THE SFC WINDS NW AHEAD OF THE ACTUAL
FRONT...AND THUS SEEMED TO BE HAVING TROUBLE MAINTAINING THE
IDENTIFY OF THE FRONT. THE RAP SEEMS TO BE HANDLING THE SITN ABOUT
THE BEST. DESPITE AN ANTICIPATED STG SWD PUSH OF THE FRONT /THERE
ARE CURRENTLY 5 MB 3-HR PRESSURE RISES ON ERN LAKE SUPERIOR/
CURRENT POSN OF THE FRONT SUGGESTS DELAYING ITS ARRIVAL A BIT.
THAT SHOULD ALLOW TEMPS ACRS THE SRN PART OF THE FCST AREA TO WARM
QUICKLY THIS MORNING. RAISED MAXES THERE.
FRONT WL SURGE SWD DOWN THE BAY/LAKESHORE...BUT MAY SLOW OVER THE
SW PART OF THE FCST AREA. SOME LOW-LEVEL MOISTURE IS POOLED ALONG
THE BOUNDARY BACK TO THE W. THAT WL PROBABLY MAKE IT INTO CENTRAL
WI MID-DAY. GIVEN THE CONVERGENCE ALONG THE FRONT...STARTING TO
HAVE CONCERNS THAT AN ISOLD SHRA/TSRA COULD DEVELOP OVER THE SW
CORNER OF THE FCST AREA THIS AFTN. NOT ENOUGH SUPPORT TO ADD TO
THE FCST YET...BUT TRENDED POPS UP TO SILENT 14/S OVER THE SW.
COOLER AND DRIER AIR WITH CANADIAN HIGH WL BECOME ESTABLISHED
ACRS THE AREA TNGT. COULD SEE A FEW CLDS COME OFF THE BAY LATE.
OTHERWISE...EXPECT MAINLY CLR SKIES. WITH WINDS LIKELY DYING OFF
LATE TNGT ACRS THE N...EXPECT THE TYPICAL COLD SPOTS TO DROP INTO
THE 30S. PATCHY FROST IS POSSIBLE IN THESE AREAS BY MORNING.
PLENTY OF SUN IS EXPECTED THU AS HIGH PRESSURE DOMINATES. ELY
FLOW WL KEEP THE LAKESHORE A LITTLE COOLER...BUT DRY AIR SHOULD
ALLOW FOR TEMPS AT MOST LOCATIONS TO REACH AOA NORMAL LEVELS
DESPITE THE CHILLY START TO THE DAY IN THE N.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 339 AM CDT WED SEP 4 2013
NORTHWEST FLOW WILL CONTINUE INTO THE WEEKEND AS 500MB RIDGE
REMAINS ANCHORED ACROSS THE CENTRAL PLAINS. THE 500MB RIDGE SHOULD
SHIFT EAST EARLY NEXT WEEK...THEN BREAK DOWN AS UPPER TROUGH
SWINGS ACROSS THE NORTHERN UNITED STATES. BEYOND THE FORECAST
PERIOD...500MB RIDGE IS EXPECTED TO BUILD ACROSS THE WESTERN
UNITED STATES WITH A NORTHWEST FLOW PATTERN TO BE REESTABLISHED
ACROSS THE WESTERN LAKES.
MODELS CONTINUE TO STRUGGLE AMONGST THEMSELVES AND FROM MODEL RUN
TO RUN ON WHERE TO FOCUS PRECIPITATION THURSDAY NIGHT INTO FRIDAY.
THIS IS ESPECIALLY TRUE FOR THE ECMWF...WHICH TYPICALLY TRENDS
BETTER IN THE MID RANGE PERIOD OF THE FORECAST. THUS CONFIDENCE
IS LOW IN WHEN AND WHERE TO PLACE HIGHEST CHANCES FOR RAIN
THURSDAY NIGHT THROUGH SUNDAY.
IT APPEARS THERE IS A BETTER CHANCE OF SHOWERS AND STORMS AT TIMES
SUNDAY NIGHT THROUGH TUESDAY NIGHT DEPENDING ON WHERE FRONTAL
BOUNDARY ACTUALLY SETS UP. COULD BE A FEW ROUNDS OF SHOWERS AND
STORMS WITH LOCALLY HEAVY RAIN...ASSUMING FIRST ROUND OR TWO OF
SHOWERS AND STORMS DOES NOT PUSH THE BOUNDARY FURTHER SOUTH.
PLENTY OF TIME TO WATCH THIS UNFOLD.
PREVIOUS SHIFT LOWERED MAXIMUM TEMPERATURES ON MONDAY AND THIS
STILL SEEMS REASONABLE. MAY NEED TO COOL IT DOWN EVEN A FEW MORE
DEGREES DUE TO CLOUD COVER AND EXPECTED RAIN FROM AN APPROACHING
WARM FRONT. HIGHS ON TUESDAY AND WEDNESDAY WILL BE DETERMINED BY
HOW MUCH SUN/LACK OF RAIN THAT OCCURS DURING THE DAY AND WHERE
WARM FRONT SETS UP.
&&
.AVIATION...FOR 12Z TAF ISSUANCE
ISSUED AT 339 AM CDT WED SEP 4 2013
NARROW BAND OF MVFR CIGS COULD BRUSH THE N RIGHT BEHIND THE FRONT
THIS MORNING...BUT THEY SHOULD MIX OUT DURING THE DAY. MVFR CIGS
ALSO POSSIBLE AT GRB LATE TNGT IF CLDS COME OFF THE BAY....AND MAY
NEED TO CARRY THAT AS A TEMPO GROUP FOR LATE TNGT.
&&
.MARINE...
ISSUED AT 339 AM CDT WED SEP 4 2013
W/SW WINDS EARLY TDA WL SHIFT TO THE NNE AS A SHARP COLD FRONT
SURGES SWD DOWN LAKE MICHIGAN AND THE BAY OF GREEN BAY. GUSTS ABV
25 KTS ARE LIKELY WITH THE FROPA AND FOR A COUPLE HRS AFTERWARD...
THEN WINDS SHOULD BEGIN TO SETTLE BACK DOWN. DURATION PROBABLY
WON/T BE SUFFICIENT TO DRIVE WAVES ABV 4 FT...THOUGH IT COULD GET
VERY CHOPPY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......SKOWRONSKI
MARINE.........SKOWRONSKI
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT TUE SEP 3 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 239 PM CDT TUE SEP 3 2013
..CURRENTLY AS OF 19Z..
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED AN UPPER LOW
JUST OFF THE PACIFIC NORTHWEST COAST...SUBTROPICAL RIDGING FROM
COLORADO INTO ALBERTA...AND TROUGHING FROM HUDSON BAY DOWN ALONG THE
EAST COAST OF THE U.S.. WITHIN THIS TROUGHING...THE MAIN FEATURE OF
NOTE IS A POTENT SHORTWAVE DROPPING THROUGH NORTHERN MANITOBA AND
ONTARIO...WHICH IS REFLECTED AT THE SURFACE BY A COLD FRONT THAT IS
APPROACHING FAR NORTHWEST MN. HIGH PRESSURE AND DRY AIR DOMINATE THE
FORECAST AREA. THE DRY AIR IS REFLECTED WELL ON THE 12Z SOUNDINGS
FROM MPX...GRB AND DVN WITH PRECIPITABLE WATER VALUES AROUND 0.68
INCHES OR 80 PERCENT OF NORMAL. SOME MID AND HIGH CLOUDS HAVE BEEN
SPREADING INTO THE AREA FROM THE DAKOTAS AND MINNESOTA...ASSOCIATED
WITH SOME WEAK 850MB MOISTURE TRANSPORT AHEAD OF THE COLD FRONT...AS
WELL AS WEAK 320K ISENTROPIC LIFT. THE MID AND HIGH CLOUDS ALSO
REFLECT SEPARATION OF WARMTH ACROSS THE UPPER MIDWEST. 12Z SOUNDINGS
FROM BIS AND ABR HAD 925MB TEMPS AROUND 20C...WHEREAS GRB...DVN AND
MPX WERE AROUND 12C.
..HAZARDS..
NONE.
..SYNOPTIC OVERVIEW..
03.12Z MODEL GUIDANCE REMAINS CONSISTENT IN DEVELOPING AN
ANOMALOUSLY DEEP TROUGH OVER THE HUDSON BAY REGION DURING THE NEXT
24 HOURS. THIS TROUGH HELPS PROPEL THE COLD FRONT CURRENTLY DROPPING
INTO NORTHWEST MN THROUGH THE FORECAST AREA DURING THE DAY
WEDNESDAY. CANADIAN HIGH PRESSURE LOOKS TO BUILD INTO NORTHERN MN
AND UPPER MI BEHIND THE FRONT LATE WEDNESDAY.
..DETAILS..
PLENTIFUL DRY AIR IN THE LOW LEVELS OF THE TROPOSPHERE FOR THE NEXT
24 HOURS...COMBINED WITH CAPPING ADVECTING IN AT 800MB AHEAD OF THE
COLD FRONT DROPPING SOUTH WILL HELP TO KEEP CONDITIONS DRY THROUGH
THE SHORT TERM PERIOD. 03.12Z NAM BMJ CONVECTIVE SCHEME GOES OFF
WEDNESDAY AFTERNOON WEST OF THE MISSISSIPPI RIVER...BUT THINK IT IS
REMOVING THE CAPPING WAY TOO QUICK GIVEN THAT THE 03.12Z GFS DEPICTS
160 J/KG OF CIN AT THE SAME TIME.
ALTHOUGH CONDITIONS ARE EXPECTED TO BE DRY...THERE ARE SOME CLOUD
COVER CONCERNS WHICH TIE INTO TEMPERATURES AND POTENTIAL FOR VALLEY
FOG. INDICATIONS ARE THAT THE CURRENT CIRRUS OVER THE FORECAST AREA
WILL CLEAR THE AREA THIS EVENING. THE NEXT BATCH OF MID/HIGH CLOUDS
UPSTREAM OVER SOUTHERN SASKATCHEWAN AND NORTHERN NORTH DAKOTA LOOK
TO MOVE INTO THE AREA LATE TONIGHT AND PERSIST THROUGH MUCH OF
TOMORROW. GOOD RADIATIONAL COOLING CONDITIONS EXIST BETWEEN THE TWO
BATCHES OF CLOUDS...WHICH SHOULD ALLOW TEMPS TO BOTTOM OUT INTO THE
UPPER 40S TO MID 50S. THE INCREASE IN CLOUDS LATE TONIGHT ALONG WITH
MODELS INCREASING 950-975MB WINDS AHEAD OF THE FRONT SHOULD KEEP ANY
VALLEY FOG THAT FORMS TO MOSTLY THE MISSISSIPPI RIVER TRIBUTARIES...
THOUGH CANNOT RULE OUT PATCHES OF FOG IN THE MISSISSIPPI RIVER
VALLEY. 925MB TEMPS ON WEDNESDAY ARE PROGGED TO CLIMB TO 19-24C...
COOLEST OVER TAYLOR COUNTY. THESE READINGS COMBINED WITH SUNSHINE
FILTERING THROUGH THE CLOUDS WILL ALLOW HIGHS TO TOP OUT IN THE
UPPER 70S TO MID 80S. A FEW SPOTS MAY EVEN HIT THE UPPER 80S...
DEPENDING ON THE AMOUNT OF SUN...AND MOST LIKELY TO OCCUR IN THE
WISCONSIN RIVER VALLEY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 239 PM CDT TUE SEP 3 2013
..HAZARDS..
1. HEAT. MODELS ARE HINTING AT A SURGE OF HEAT COMING INTO THE
FORECAST AREA ON SATURDAY. RIGHT NOW IT APPEARS HEAT INDICES WILL
STAY BELOW ADVISORY CRITERIA...THOUGH.
2. STORMS. THERE ARE CHANCES IN THE FORECAST FOR FRIDAY NIGHT AND
BEYOND. IF THERE IS ANY SEVERE POSSIBILITY...IT WOULD COME EARLY
NEXT WEEK...BUT THERE IS STILL PLENTY OF TIME FOR THIS TO CHANGE.
..SYNOPTIC OVERVIEW..
03.12Z ECMWF/GFS/CANADIAN AND ENSEMBLE DATA ALL SUGGEST A SLOW
PROGRESSION EASTWARD OF THE UPPER LEVEL PATTERN DURING THE NEXT 7
DAYS. MUCH OF THIS PROGRESSION HAS TO WAIT UNTIL FRIDAY BECAUSE OF
THE ANOMALOUSLY DEEP TROUGH SET UP OVER THE HUDSON BAY REGION AND
SOUTHEAST CANADA. BY MONDAY...MODELS PROG THAT THE UPPER LOW
CURRENTLY OFF THE PACIFIC NORTHWEST COAST WILL HAVE SLID INLAND INTO
MONTANA...WHILE THE RIDGE AXIS AHEAD OF IT OVER ALBERTA MOVES EAST
TO OVER THE FORECAST AREA. THEN FOR TUESDAY...INDICATIONS ARE THAT
TROUGHING WILL BE CROSSING MANITOBA...SENDING A COLD FRONT TOWARDS
THE AREA. THE CHANGE IN THE UPPER LEVEL PATTERN MEANS THAT BY THE
WEEKEND...WARM AIR ADVECTION WILL BE IN FORCE...BRINGING CONCERNS OF
CAPPING...PRECIPITATION AND POSSIBLY MUGGY CONDITIONS AGAIN.
..DETAILS..
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...DRY CONDITIONS WILL
DOMINATE THIS PERIOD WITH SUBSIDENCE AND DRY AIR IN PLACE...ALONG
WITH HIGH PRESSURE TRACKING SOUTHEAST ACROSS THE WESTERN GREAT LAKES
REGION. SKIES SHOULD CLEAR OUT NORTH TO SOUTH WEDNESDAY NIGHT AS THE
UPPER FLOW TURNS A BIT MORE NORTHERLY...FOLLOWED BY FULL SUN ON
THURSDAY AND SOME INCREASE IN WARM ADVECTION MID/HIGH CLOUDS LATE
THURSDAY NIGHT. VALLEY FOG CONCERNS...AT LEAST IN THE MISSISSIPPI
RIVER...SHOULD BE MINIMIZED BY POTENTIAL ISSUES WITH CLOUDS AND AN
EASTERLY BREEZE RIGHT ABOVE THE SURFACE. LOWS WILL ALSO BE ON THE
COOL SIDE...ESPECIALLY IN WISCONSIN WHERE THE HIGH TRACKS ACROSS.
HIGHS ON THURSDAY SHOULD BE A LITTLE COOLER THAN WEDNESDAY DUE TO
925MB TEMPS TOPPING OUT BETWEEN 18-22C.
FRIDAY THROUGH TUESDAY...FOCUS IS ON THE WARM ADVECTION PATTERN THAT
DEVELOPS.
1. TEMPERATURES...850MB ANOMALIES ARE PROGGED BETWEEN 0.5-1 ABOVE ON
FRIDAY AND SUNDAY...AND 1.5-2 ABOVE FOR SATURDAY...MONDAY AND
TUESDAY. THESE WILL KEEP US BELOW RECORDS BUT ABOVE TO WELL ABOVE
NORMAL NONETHELESS. 925MB TEMPS CLIMB TO 22-26C ON FRIDAY...24-29C
ON SATURDAY...COOL TO 18-21C ON SUNDAY AND MONDAY AND CLIMB BACK UP
TO 24-29C ON TUESDAY. THE WARMEST READINGS ARE SUGGESTED OVER
NORTHEAST IOWA. MEANWHILE...THE COOLEST READINGS ARE PROGGED OVER
TAYLOR/CLARK COUNTIES WHICH ARE CLOSER TO A CANADIAN HIGH TRACKING
ACROSS SOUTH CENTRAL CANADA AND THE UPPER GREAT LAKES.
2. MUGGY-NESS...GULF OF MEXICO MOISTURE WILL RETURN BACK INTO THE
REGION BUT ITS GOING TO TAKE SOME TIME DUE TO THE CANADIAN HIGH
MOVING ACROSS ON THURSDAY. ADDITIONALLY...THE DROUGHT CONDITIONS
THAT HAVE DEVELOPED WILL HELP TO MIX OUT THIS MOISTURE. THE BETTER
SHOT FOR MORE MUGGY CONDITIONS LOOKS TO COME THIS THE WEEKEND INTO
EARLY NEXT WEEK AS MOISTURE POOLS ALONG A FRONTAL BOUNDARY PROGGED
TO SET UP NEAR THE FORECAST AREA. EVEN STILL...DEWPOINTS DO NOT
APPEAR AS HIGH AS THEY WERE DURING THE HEAT WAVE LAST WEEK.
3. PRECIPITATION CHANCES...MODELS ARE IN GOOD AGREEMENT HOLDING
FRIDAY DRY. THERE COULD BE SOME ELEVATED CONVECTION ON THE EDGE OF
THE WARM SURGE / CAPPING OVER WISCONSIN FRIDAY NIGHT AND SATURDAY...
AND HAVE 20-30 PERCENT CHANCES FOR THEM. FROM SATURDAY NIGHT
ONWARDS...ALL BETS ARE OFF WITH THE 03.12Z ECMWF/CANADIAN/GFS ALL
SHOWING PERIODS OF PRECIPITATION. VERY HARD TO PIN THESE
DOWN...GIVEN FRONTAL BOUNDARY POSITION UNCERTAINTY. ADDITIONALLY...
THE IMPACT OF THE DROUGHT COULD END UP LIMITING THE AMOUNT OF
PRECIPITATION...PARTICULARLY IN THE DAYTIME. FOR NOW FOLLOWED A
MODEL CONSENSUS OF GENERALLY 20-40 PERCENT CHANCES EVERY 12 HOURS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1140 PM CDT TUE SEP 3 2013
THE MAIN FOCUS INTO TOMORROW IS WITH THE POTENTIAL VALLEY FOG
TONIGHT FOLLOWED BY A COLD FRONT PASSAGE TOMORROW MORNING. SKIES
HAVE MAINLY BE CLEAR THIS EVENING WHICH HAS ALLOWED FOR
TEMPERATURES TO QUICKLY DROP OFF WHILE THE DEW POINT HAS COME UP A
BIT. WINDS HAVE BEEN ON THE LIGHT SIDE...EVEN GOING CALM AT TIMES.
SOME OF THE LATEST MODEL GUIDANCE IS SHOWING SOME SLIGHTLY SLOWER
LOW LEVEL WINDS GOING INTO TOMORROW MORNING...SO THE POTENTIAL
SEEMS TO BE A LITTLE HIGHER THAN SOME VALLEY FOG WILL FORM
OVERNIGHT. WINDS ARE STILL BLOWING UP ON THE RIDGE TOPS AT
5-10MPH...SO THAT MAY HOLD BACK THE DEVELOPMENT TO JUST BEFORE
SUNRISE. THIS FOG SHOULD QUICKLY DISSIPATE AS A COLD FRONT MOVES
THROUGH THE REGION AROUND 14Z. WINDS WILL SHIFT AROUND TO THE
NORTHWEST WITH THE MAIN MID LEVEL CLOUD DECK GOING THROUGH EASTERN
WISCONSIN WITH THIS FEATURE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1038 AM CDT WED SEP 4 2013
.UPDATE...
ISSUED AT 1032 AM CDT WED SEP 4 2013
...UPDATED TODAY...
UPDATES FOR TODAY HAVE TO DO WITH STRONG OFF-LAKE WINDS. CLOUDS
NEAR LAKE WILL BE HANGING ON A BIT LONGER THAN PREVIOUS FORECAST.
CURRENT VIS SAT DOES SHOW THE CLOUDS THINNING A BREAKING UP BUT
BUFR SOUNDINGS INDICATE CLEARING A FEW HOURS LATER THAT
FCST...ABOUT MID AFTERNOON. ALSO UPDATED TO REFLECT THE STRONGER
WINDS AND COOLER TEMPS AT THE LAKE. LATEST LIFT BRIDGE OB HAD 56
DEGREES WITH 21 MPH WINDS.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 349 AM CDT WED SEP 4 2013
AT 345AM/0845Z...A COLD FRONT STRETCHED FROM EAST TO WEST ACROSS
LAKE SUPERIOR...NORTHERN MINNESOTA...AND SOUTHEASTERN NORTH
DAKOTA. STRONG SURFACE HIGH PRESSURE WAS CENTERED NEAR SOUTHERN
MANITOBA. A LARGE MID/UPPER LEVEL RIDGE WAS CENTERED NEAR
COLORADO/KANSAS WITH THE AXIS EXTENDING NORTH TO CENTRAL MONTANA
AND INTO WESTERN CANADA. MUCH OF THE NORTHLAND HAD LIGHT TO NEARLY
CALM WINDS...BUT 5 TO 10 KNOT NORTHERLY WINDS WERE DEVELOPING
ACROSS FAR NORTHERN MINNESOTA IN THE WAKE OF THE COLD FRONT.
TEMPERATURES RANGED FROM THE MID 50S TO MID 60S...WITH MOST OF THE
NORTHLAND IN THE UPPER 50S AND LOWER 60S. THERE WERE INCREASING
PATCHES OF BKN/OVC LOW LEVEL CLOUDS ACROSS THE EASTERN AND
SOUTHERN FORECAST AREAS...ESPECIALLY OVER THE ARROWHEAD AND LAKE
SUPERIOR.
EARLY THIS MORNING...THE COLD FRONT WILL CONTINUE MOVING SOUTH
THROUGH THE NORTHLAND. BASED ON THE HRRR AND RAP...IT APPEARS
THERE WILL BE INCREASING CLOUD COVER OVER LAKE SUPERIOR AND PARTS
OF THE SOUTHERN FORECAST AREA IN THE WAKE OF THE COLD FRONT. IN
THE CASE OF LAKE SUPERIOR AND NW WISCONSIN...THIS IS LIKELY DUE TO
THE ADDED MOISTURE THE INCREASING NORTHERLY WINDS WILL PROVIDE
FROM LAKE SUPERIOR. I RAISED THE MORNING LOW TEMPERATURES A BIT
BECAUSE THE LIGHT WINDS ACROSS THE NORTHLAND AND THE MOISTURE
COMPRESSION NEAR THE FRONT SEEM TO BE PREVENTING THE TEMPERATURES
FROM FALLING MUCH THIS MORNING.
TODAY...THE SURFACE HIGH PRESSURE IN SOUTHERN MANITOBA WILL MOVE
OVER NORTHERN MINNESOTA. THIS SHOULD PROVIDE MOSTLY TO PARTLY
SUNNY SKIES FOR THE NORTHLAND AFTER THE LINGERING MORNING BKN/OVC
LOW LEVEL CLOUDS DISSIPATE. THERE MAY BE SOME MID/HIGH LEVEL
CLOUDS ACROSS THE SOUTHERN AND WESTERN FORECAST AREA AS THE MODELS
SHOW SOME SATURATION ALOFT ALONG SOME WEAK CHANNELED VORTICITY
STRETCHING FROM THE UPPER MIDWEST TO SOUTH CENTRAL CANADA ON THE
EASTERN SIDE OF A MID/UPPER LEVEL RIDGE. HIGH TEMPERATURES SHOULD
RANGE THE MID 60S TO MID 70S WITH THE COOLER TEMPERATURES ACROSS
NORTHERN MINNESOTA.
TONIGHT...THE SURFACE HIGH PRESSURE WILL BEGIN TO SHIFT TOWARD
NORTHERN WISCONSIN AND LAKE MICHIGAN. THE NORTHLAND CAN EXPECT
CLEAR TO MOSTLY CLEAR SKIES AND LIGHT TO CALM WINDS. THE COLD
FRONT WILL USHER IN LOW DEW POINT TEMPERATURES...AND THIS COMBINED
WITH THE LACK OF WINDS AND CLOUDS...WILL ALLOW TEMPERATURES TO
DROP QUITE A BIT. MUCH OF INLAND NORTHERN MINNESOTA AND PARTS OF
INLAND NW WISCONSIN SHOULD SEE TEMPERATURES DROP TO THE UPPER 30S
AND LOW 40S. THIS MEANS SOME AREAS COULD SEE FROST AND WE WILL
NEED TO CONSIDER THE NEED FOR A FROST ADVISORY. HOWEVER...THE MOST
RECENT MODELS SHOW SLIGHTLY HIGHER DEW POINT
TEMPERATURES...ESPECIALLY OVER NW WISCONSIN...COMPARED TO THE
PREVIOUS FORECAST. ALSO...I SLIGHTLY RAISED TEMPERATURES. I AM NOT
CONFIDENT OF ANY WIDESPREAD FROST...SO I KICK THE CAN TO THE DAY
SHIFT TO MAKE A FINAL DECISION ON A FROST ADVISORY. THE MOST
LIKELY AREA FOR FROST IS ACROSS THE IRON RANGE AND THE INTERIOR
ARROWHEAD.
THURSDAY...THE SURFACE HIGH PRESSURE WILL SHIFT EAST TO THE
MICHIGAN AND THE EASTERN GREAT LAKES. LIGHT SOUTHERLY FLOW OVER
THE NORTHLAND AND SUNNY SKIES WILL PROVIDE A WARMER DAY WITH
TEMPERATURES REACHING THE UPPER 60S TO UPPER 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 349 AM CDT WED SEP 4 2013
THURSDAY NIGHT OUR SURFACE RIDGE SLIPS OFF TO THE SOUTHEAST
AGAIN...WITH SOUTHWEST FLOW BEGINNING AGAIN OVER THE FORECAST
AREA. THIS SHOULD KEEP OUR TEMPERATURES UP IN THE 50S OVERNIGHT.
A SHORTWAVE DIVING THROUGH THE NORTHWEST UPPER LEVEL FLOW MAY
BRING A FEW SHOWERS AND THUNDERSTORMS TO THE AREA OVERNIGHT...BUT
THIS WILL BE LIMITED TO THE FAR NORTHERN SECTIONS OF THE AREA. WE
ARE JUST GOING TO GET A GLANCING BLOW...SO HAVE KEPT POPS IN THE
SLIGHT CHANCE CATEGORY BOTH THURSDAY NIGHT AND FRIDAY. HIGHS
FRIDAY TO BE WARM AS WELL...IN THE LOW TO MID 80S.
FRIDAY NIGHT THROUGH SATURDAY TO BE ACTIVE WITH A FEW MORE
SHORTWAVE OVERTOPPING THE UPPER LEVEL RIDGE OVER THE ROCKIES...AND
A COLD FRONT DROPS THROUGH THE AREA FRIDAY NIGHT AND SATURDAY AS
WELL. HAVE SOME SLIGHT CHANCE AND CHANCE POPS GOING...WHICH MAY BE
RAISED AS DETAILS BECOME CLEAR. WARM TEMPERATURES ARE EXPECTED TO
CONTINUE. SATURDAY NIGHT SHOULD BE QUIET AND DRIER.
BEGINNING SUNDAY UNCERTAINTY INCREASES OVER THE AREA WITH THE
UPPER LEVEL RIDGE FLATTENING AND SHIFTING EAST...ALLOWING A
FAIRLY STRONG SHORTWAVE TO MOVE ACROSS THE AREA IN THE TUESDAY-
WEDNESDAY TIME RANGE. MODELS HAVE VARYING SOLUTIONS...BUT
GENERALLY TEMPERATURES COOL OFF BACK TOWARDS NORMAL VALUES
AGAIN...WITH PRECIPITATION CHANCES BEGINNING SUNDAY AND CONTINUING
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 653 AM CDT WED SEP 4 2013
A COLD FRONT IN THE PROCESS OF MOVING THROUGHT THE TERMINALS THIS
MORNING. BEHIND THE FRONT LIGHT NORTH WINDS ARE BEGINNING TO
SETTLE IN. WINDS ARE STRONGER OVER THE LAKE AND MVFR STRATUS THAT
FORMED OVER THE LAKE HAS ADVECTED OVER KDLH...AND IS CLOSE TO
MOVING INTO KHYR. KHIB A LITTLE FARTHER AWAY/LESS CERTAIN. THIS
STRATUS TO AFFECT THESE THREE TERMINALS THROUGH ABOUT 18Z BEFORE
BECOMING SCATTERED THIS AFTERNOON. REMAINING TERMINALS TO STAY
VFR. ONCE VFR CONDITIONS RETURN THIS AFTERNOON EXPECT THEM TO STAY
THAT WAY THROUGH 12Z THURSDAY MORNING AS A STRONG SURFACE RIDGE
MOVES ACROSS THE AREA TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 68 44 74 56 / 0 0 0 10
INL 67 39 77 56 / 0 0 0 20
BRD 76 46 80 60 / 0 0 0 0
HYR 73 39 78 55 / 0 0 0 0
ASX 66 41 74 56 / 0 0 0 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
142>148.
&&
$$
UPDATE...CLC
AREA FORECAST DISCUSSION
NWS DULUTH MN
654 AM CDT WED SEP 4 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 349 AM CDT WED SEP 4 2013
AT 345AM/0845Z...A COLD FRONT STRETCHED FROM EAST TO WEST ACROSS
LAKE SUPERIOR...NORTHERN MINNESOTA...AND SOUTHEASTERN NORTH
DAKOTA. STRONG SURFACE HIGH PRESSURE WAS CENTERED NEAR SOUTHERN
MANITOBA. A LARGE MID/UPPER LEVEL RIDGE WAS CENTERED NEAR
COLORADO/KANSAS WITH THE AXIS EXTENDING NORTH TO CENTRAL MONTANA
AND INTO WESTERN CANADA. MUCH OF THE NORTHLAND HAD LIGHT TO NEARLY
CALM WINDS...BUT 5 TO 10 KNOT NORTHERLY WINDS WERE DEVELOPING
ACROSS FAR NORTHERN MINNESOTA IN THE WAKE OF THE COLD FRONT.
TEMPERATURES RANGED FROM THE MID 50S TO MID 60S...WITH MOST OF THE
NORTHLAND IN THE UPPER 50S AND LOWER 60S. THERE WERE INCREASING
PATCHES OF BKN/OVC LOW LEVEL CLOUDS ACROSS THE EASTERN AND
SOUTHERN FORECAST AREAS...ESPECIALLY OVER THE ARROWHEAD AND LAKE
SUPERIOR.
EARLY THIS MORNING...THE COLD FRONT WILL CONTINUE MOVING SOUTH
THROUGH THE NORTHLAND. BASED ON THE HRRR AND RAP...IT APPEARS
THERE WILL BE INCREASING CLOUD COVER OVER LAKE SUPERIOR AND PARTS
OF THE SOUTHERN FORECAST AREA IN THE WAKE OF THE COLD FRONT. IN
THE CASE OF LAKE SUPERIOR AND NW WISCONSIN...THIS IS LIKELY DUE TO
THE ADDED MOISTURE THE INCREASING NORTHERLY WINDS WILL PROVIDE
FROM LAKE SUPERIOR. I RAISED THE MORNING LOW TEMPERATURES A BIT
BECAUSE THE LIGHT WINDS ACROSS THE NORTHLAND AND THE MOISTURE
COMPRESSION NEAR THE FRONT SEEM TO BE PREVENTING THE TEMPERATURES
FROM FALLING MUCH THIS MORNING.
TODAY...THE SURFACE HIGH PRESSURE IN SOUTHERN MANITOBA WILL MOVE
OVER NORTHERN MINNESOTA. THIS SHOULD PROVIDE MOSTLY TO PARTLY
SUNNY SKIES FOR THE NORTHLAND AFTER THE LINGERING MORNING BKN/OVC
LOW LEVEL CLOUDS DISSIPATE. THERE MAY BE SOME MID/HIGH LEVEL
CLOUDS ACROSS THE SOUTHERN AND WESTERN FORECAST AREA AS THE MODELS
SHOW SOME SATURATION ALOFT ALONG SOME WEAK CHANNELED VORTICITY
STRETCHING FROM THE UPPER MIDWEST TO SOUTH CENTRAL CANADA ON THE
EASTERN SIDE OF A MID/UPPER LEVEL RIDGE. HIGH TEMPERATURES SHOULD
RANGE THE MID 60S TO MID 70S WITH THE COOLER TEMPERATURES ACROSS
NORTHERN MINNESOTA.
TONIGHT...THE SURFACE HIGH PRESSURE WILL BEGIN TO SHIFT TOWARD
NORTHERN WISCONSIN AND LAKE MICHIGAN. THE NORTHLAND CAN EXPECT
CLEAR TO MOSTLY CLEAR SKIES AND LIGHT TO CALM WINDS. THE COLD
FRONT WILL USHER IN LOW DEW POINT TEMPERATURES...AND THIS COMBINED
WITH THE LACK OF WINDS AND CLOUDS...WILL ALLOW TEMPERATURES TO
DROP QUITE A BIT. MUCH OF INLAND NORTHERN MINNESOTA AND PARTS OF
INLAND NW WISCONSIN SHOULD SEE TEMPERATURES DROP TO THE UPPER 30S
AND LOW 40S. THIS MEANS SOME AREAS COULD SEE FROST AND WE WILL
NEED TO CONSIDER THE NEED FOR A FROST ADVISORY. HOWEVER...THE MOST
RECENT MODELS SHOW SLIGHTLY HIGHER DEW POINT
TEMPERATURES...ESPECIALLY OVER NW WISCONSIN...COMPARED TO THE
PREVIOUS FORECAST. ALSO...I SLIGHTLY RAISED TEMPERATURES. I AM NOT
CONFIDENT OF ANY WIDESPREAD FROST...SO I KICK THE CAN TO THE DAY
SHIFT TO MAKE A FINAL DECISION ON A FROST ADVISORY. THE MOST
LIKELY AREA FOR FROST IS ACROSS THE IRON RANGE AND THE INTERIOR
ARROWHEAD.
THURSDAY...THE SURFACE HIGH PRESSURE WILL SHIFT EAST TO THE
MICHIGAN AND THE EASTERN GREAT LAKES. LIGHT SOUTHERLY FLOW OVER
THE NORTHLAND AND SUNNY SKIES WILL PROVIDE A WARMER DAY WITH
TEMPERATURES REACHING THE UPPER 60S TO UPPER 70S.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 349 AM CDT WED SEP 4 2013
THURSDAY NIGHT OUR SURFACE RIDGE SLIPS OFF TO THE SOUTHEAST
AGAIN...WITH SOUTHWEST FLOW BEGINNING AGAIN OVER THE FORECAST
AREA. THIS SHOULD KEEP OUR TEMPERATURES UP IN THE 50S OVERNIGHT.
A SHORTWAVE DIVING THROUGH THE NORTHWEST UPPER LEVEL FLOW MAY
BRING A FEW SHOWERS AND THUNDERSTORMS TO THE AREA OVERNIGHT...BUT
THIS WILL BE LIMITED TO THE FAR NORTHERN SECTIONS OF THE AREA. WE
ARE JUST GOING TO GET A GLANCING BLOW...SO HAVE KEPT POPS IN THE
SLIGHT CHANCE CATEGORY BOTH THURSDAY NIGHT AND FRIDAY. HIGHS
FRIDAY TO BE WARM AS WELL...IN THE LOW TO MID 80S.
FRIDAY NIGHT THROUGH SATURDAY TO BE ACTIVE WITH A FEW MORE
SHORTWAVE OVERTOPPING THE UPPER LEVEL RIDGE OVER THE ROCKIES...AND
A COLD FRONT DROPS THROUGH THE AREA FRIDAY NIGHT AND SATURDAY AS
WELL. HAVE SOME SLIGHT CHANCE AND CHANCE POPS GOING...WHICH MAY BE
RAISED AS DETAILS BECOME CLEAR. WARM TEMPERATURES ARE EXPECTED TO
CONTINUE. SATURDAY NIGHT SHOULD BE QUIET AND DRIER.
BEGINNING SUNDAY UNCERTAINTY INCREASES OVER THE AREA WITH THE
UPPER LEVEL RIDGE FLATTENING AND SHIFTING EAST...ALLOWING A
FAIRLY STRONG SHORTWAVE TO MOVE ACROSS THE AREA IN THE TUESDAY-
WEDNESDAY TIME RANGE. MODELS HAVE VARYING SOLUTIONS...BUT
GENERALLY TEMPERATURES COOL OFF BACK TOWARDS NORMAL VALUES
AGAIN...WITH PRECIPITATION CHANCES BEGINNING SUNDAY AND CONTINUING
THROUGH TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 653 AM CDT WED SEP 4 2013
A COLD FRONT IN THE PROCESS OF MOVING THROUGHT THE TERMINALS THIS
MORNING. BEHIND THE FRONT LIGHT NORTH WINDS ARE BEGINNING TO
SETTLE IN. WINDS ARE STRONGER OVER THE LAKE AND MVFR STRATUS THAT
FORMED OVER THE LAKE HAS ADVECTED OVER KDLH...AND IS CLOSE TO
MOVING INTO KHYR. KHIB A LITTLE FARTHER AWAY/LESS CERTAIN. THIS
STRATUS TO AFFECT THESE THREE TERMINALS THROUGH ABOUT 18Z BEFORE
BECOMING SCATTERED THIS AFTERNOON. REMAINING TERMINALS TO STAY
VFR. ONCE VFR CONDITIONS RETURN THIS AFTERNOON EXPECT THEM TO STAY
THAT WAY THROUGH 12Z THURSDAY MORNING AS A STRONG SURFACE RIDGE
MOVES ACROSS THE AREA TONIGHT.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121-
142>148.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM...LE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS ELKO NV
810 AM PDT WED SEP 4 2013
.SYNOPSIS...YET ANOTHER ROUND OF THUNDERSTORMS ON TAP ACROSS
NEVADA TODAY AND TONIGHT. MANY STORMS WILL AGAIN PRODUCE VERY
HEAVY RAINFALL...AND A FLASH FLOOD WATCH IS NOW IN EFFECT THROUGH
EARLY THURSDAY MORNING. THUNDERSTORM CHANCES WILL SLOWLY DECREASE
ACROSS EASTERN NEVADA THROUGH SATURDAY.
&&
.UPDATE...SENT OUT AN UPDATED FORECAST TO INCREASE THUNDERSTORM
COVERAGE THIS AFTERNOON AND THIS EVENING, TO THE LIKELY/NUMEROUS
CATEGORY IN MANY CASES. 12Z NAM AND THE 3-KM HRRR ARE FORECASTING
ANOTHER BUSY AFTERNOON AND EVENING, WITH STORMS REDEVELOPING AGAIN
AROUND NOON. THIS MORNING`S ELKO SOUNDING IS STILL VERY MOIST WITH
PRECIPITABLE WATER NEAR 1 INCH, WITH A CONVECTIVE TEMPERATURE OF
ONLY 80 DEGREES. STORM MOTION AGAIN TODAY WILL BE TO THE NORTHEAST
AT 10-20 MPH, BUT SO FAR THAT HAS DONE LITTLE TO HINDER THE FLASH
FLOODING THREAT THE PAST FEW DAYS. CONVECTION WILL CONTINUE PAST
5 PM, WITH SOME STORMS LASTING ALL NIGHT AGAIN, SO EXTENDED THE
FLASH FLOOD WATCH THROUGH 5 AM THURSDAY MORNING. SHEAR DOES
INCREASE SOME ACROSS MAINLY NORTHERN NEVADA, IN ASSOCIATION WITH
CLOSED LOW WEST OF OREGON, SO ALSO EXPECTING A FEW SEVERE STORMS
THIS AFTERNOON, ESPECIALLY NEAR THE OREGON/IDAHO BORDERS. TURNER
&&
.PREV DISCUSSION... /ISSUED AT 316 AM /
SYNOPSIS...AS A LOW PRESSURE SYSTEM SLOWLY APPROACHES FROM OFF
THE PACIFIC COAST...ENOUGH MOISTURE WILL BE AVAILABLE TO TRIGGER
THUNDERSTORMS ALL ACROSS THE SILVER STATE AGAIN TODAY. UNSETTLED
WEATHER WILL CONTINUE ACROSS EASTERN NEVADA THROUGH SATURDAY.
SHORT TERM...TODAY THROUGH THURSDAY. A COUPLE VERY STRONG
THUNDERSTORM CELLS LINGERED PAST MIDNIGHT...IN WHITE PINE COUNTY
AND NORTHERN ELKO COUNTY. STILL A LIGHTNING STRIKE OR TWO
OCCURRING AT 3 AM PDT...EVEN IN HUMBOLDT COUNTY AS A COUPLE
UNDETECTABLE SHORTWAVES CUT THROUGH THE WEST. THE GFS MODEL SHOWS
THE TAIL END OF A COUPLE 250 MB JET STREAKS MERGING OVER CENTRAL
NEVADA BY 12Z THIS MORNING AND INSTABILITY SHOULD THEREAFTER SHUT
DOWN UNTIL HEATING INSTIGATES MORE CONVECTION LATER THIS MORNING.
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE SYNOPTIC PATTERN. A
PACIFIC LOW PRESSURE SYSTEM WILL SLOWLY MOVE ONSHORE OVER OREGON
BY THURSDAY. HIGH PRESSURE WILL HOLD POSITION OVER COLORADO AND
KANSAS HOWEVER THE INCOMING UPPER LOW WILL EFFECTIVELY SHUNT THE
MOIST FLOW ORIGINATING NEAR THE BAJA REGION.
THERE IS SOME MODEL DISCREPANCY ON PRECIPITABLE WATER AMOUNTS
TODAY HOWEVER THERE SHOULD BE PLENTY RESIDUAL MOISTURE AVAILABLE TO
ALLOW DEVELOPMENT OF SOME MORE HEAVY RAIN PRODUCING THUNDERSTORMS.
THE FLASH FLOOD WATCH HAS BEEN EXTENDED THROUGH THIS AFTERNOON
FOR PARTS OF NORTHERN AND CENTRAL NEVADA. THE DRY UPPER LOW WILL
SHOVE THE MOIST FLOW EAST BY THURSDAY. THE PRESSURE GRADIENT WILL
TIGHTEN AND BREEZY WINDS ARE EXPECTED FOR THURSDAY AFTERNOON.
LONG TERM...THURSDAY NIGHT THROUGH NEXT TUESDAY. THE FORECAST
PERIOD COMMENCES WITH A CLOSED UPPER LOW AND A POSITIVE TILT TROF
MOVING INTO THE WEST...DISPLACING THE RIDGE INTO THE CENTRAL
PLAINS. THE NCEP AND NON-NCEP MODELS ARE IN DESCENT AGREEMENT
THROUGH THE PERIOD. AS TIME ELAPSES...THE UPPER TROF WILL NUDGE
THE RIDGE EASTWARD...AND THIS PROGRESSION WILL EFFECTIVELY CUT OF
THE MONSOONAL FLOW...USHERING...A DRY AIRMASS INTO THE SILVER
STATE. ALTHOUGH...WITH PWS HOVERING AROUND .75 OF AN INCH ALONG
THE UTAH/NV BORDER...KEPT SLIGHT CHANCE POPS OVER ELKO AND WHITE
PINE COUNTIES. BY THE WEEKEND...THE MODELS START TO BECOME
SLIGHTLY OUT OF PHASE...BUT GENERALLY DEPICT WIDESPREAD NORTHWEST
DRY FLOW OVER THE CWA ON SUNDAY...MONDAY...AND TUESDAY. SENSIBLE
WEATHER-WISE EXPECT SLIGHTLY COOLER TEMPERATURES AND MOSTLY CLEAR
SKIES.
AVIATION...VFR CONDITIONS ARE EXPECTED AT KWMC KEKO...KELY AND KTPH.
HOWEVER...MONSOON MOISTURE WILL CONTINUE TO PRODUCE SHOWERS AND
THUNDERSTORMS AGAIN TODAY...WILL KEEP VC TS IN TAFS. IF THE STORMS
MOVE NEAR THE TERMINAL EXPECT...FLOODING RAINS...GUSTY WINDS...TURBULENCE
AND SMALL HAIL. THE TURBULENCE GUIDANCE FROM THE AVIATION WEATHER
CENTER SUGGESTS THAT ANY NON-CONVECTIVE TURBULENCE OVER THE REGION
WOULD BE LIGHT. OFTEN MONSOON AIR MASSES ARE SLOW TO CLEAR
OUT...EXPECTING TS OVER EASTERN NV ON THURSDAY...POTENTIALLY
IMPACTING KEKO AND KELY.
FIRE WEATHER...SHOWERS AND THUNDERSTORMS WITH WETTING RAINS WILL
DEVELOP AGAIN TODAY AND FLASH FLOODING OR DEBRIS FLOWS WILL BE A
POSSIBILITY IN SOME AREAS. A DRYING TREND IS EXPECTED BEGINNING
THURSDAY WITH THUNDERSTORMS MAINLY AFFECTING EASTERN NEVADA
THROUGH SATURDAY. BREEZY WINDS WILL DEVELOP ON THURSDAY AND
FRIDAY WITH GUSTS NEAR 30 MPH...HOWEVER HUMIDITY LEVELS ARE EXPECTED
TO BE ABOVE 15 PERCENT WHERE WINDS WILL BE STRONGEST.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NORTHERN ELKO
COUNTY...NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY...
RUBY MOUNTAINS/EAST HUMBOLDT RANGE...SOUTH CENTRAL ELKO COUNTY...
SOUTHEASTERN ELKO COUNTY...SOUTHERN LANDER COUNTY AND SOUTHERN
EUREKA COUNTY...SOUTHWESTERN ELKO COUNTY...WHITE PINE COUNTY.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1007 AM EDT WED SEP 4 2013
.SYNOPSIS...
DRIER AIR WILL BUILD OVER THE AREA TODAY IN WAKE OF A WEAK COLD
FRONT. CANADIAN HIGH PRESSURE WILL BRING A REINFORCEMENT OF DRY
AND SLIGHTLY COOLER AIR FRIDAY INTO SATURDAY. A WARMING TREND IN
EXPECTED EARLY NEXT WEEK AS AN UPPER RIDGE BUILDS OVER THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...DRIER AIR IN WAKE OF A COLD FRONT HAS
ERADICATED THE WRETCHED QUALITY OF THE MUGGY AIR MASS WHICH HAS
RECENTLY BLANKETED THE AREA. DEWPOINTS WERE DROPPING IN THE 60S
AS DRIER AIR AND MIXING WERE GETTING UNDERWAY THIS MORNING. THE
FRONT ITSELF WAS LOSING IDENTITY OFFSHORE NEARING THE GULF-STREAM
AND WAS CURLED BACK TOWARD THE SW SOUTH OF WINYAH BAY AND YAWKEY
SOUTH ISLAND RESERVE. HIGH RESOLUTION NEAR TERM MODELS WRF NSSL
AND THE HRRR DEPICT SIMILAR SOLUTIONS...ISOLATED SHOWERS FAVORED
OVER OUR SOUTHERN COASTAL INTERIOR ZONES WHERE HIGH MOISTURE
CONTENT PREVAILS. AFTERNOON SEA BREEZE CONVERGENCE WILL ALLOW A
FEW MODERATE CUMULUS BUILD UPS. UPPER LEVEL MOISTURE REMAINS
SPARSE SO ONLY SHOWERS ARE ADVERTISED VERSUS TSTMS. THE BEST
CHANCE OF A SHOWER WILL BE BETWEEN 2PM-6PM. DIURNAL COOLING
SHOULD QUICKLY DIMINISH CONVECTION INTO EARLY EVENING. LOWS
TONIGHT UNDER CLEAR SKIES MAINLY MIDDLE AND UPPER 60S WITH
LOWER 70S ALONG THE COAST IN A LIGHT SOUTHERLY WIND FLOW.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM WEDNESDAY...COLD FRONT STALLED NOT TO FAR OFFSHORE BUT A
SECONDARY AXIS OF WEAK CONVERGENCE DEVELOPS ALONG THE COASTAL PLAIN
IN ASSOCIATION WITH A SURFACE TROUGH. FORECAST SOUNDINGS SHOW VERY
DRY MID LEVELS AND SO MEASURABLE PRECIPITATION SEEMS QUITE UNLIKELY
BUT A SLIGHT CHANCE WILL BE CARRIED ALONG COASTAL ZONES IN THE EVENT
OF A STRAY 0.01". WHAT LITTLE CAA BEHIND THE BOUNDARY THERE HAD
BEEN ON WED WILL BE GONE BY THURS AND TEMPS TO BE BACK A FEW DEGREES
ABOVE CLIMO. MORE APPRECIABLE FRONT TO COME THROUGH EITHER THURSDAY
NIGHT OR FRIDAY MORNING DEPENDING ON MODEL CHOICE. GIVEN THE STRONG
SURFACE PRESSURE ADVECTION PUSHING IT PREFER THE QUICKER TIMING I.E.
WRF. FRIDAY HIGHS KNOCKED BACK DOWN A FEW DEGREES BELOW CLIMO AND
DEWPOINTS TO FALL INTO THE MID OR EVEN LOW 60S...THE LATTER MOST
LIKELY OVER NW ZONES. FAR SRN SC ZONES MAY HOLD ON TO DEWPOINTS IN
THE UPPER 60S. INTERESTING SKY COVER FORECAST LATE FRIDAY INTO
FRIDAY NIGHT AS GUIDANCE SHOWING SOME ATLANTIC MOISTURE ASSOC WITH
THE NE SURGE. MID LEVELS REMAIN VERY DRY...PROBABLY DRIER THAN FCST
SOUNDINGS SHOW IN THE CONTINUED NW FLOW...AND WITH NO NOTICEABLE
FRONTAL INVERSION THIS MOISTURE MAY NOT GET TRAPPED AS MUCH AS THE
RELATIVELY CLOUDY GUIDANCE IMPLIES.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...VERY QUIET WEATHER ON TAP FOR THE PERIOD.
UPPER RIDGE REMAINS ACROSS THE PLAINS THROUGH SUNDAY OR MONDAY WHILE
SURFACE HIGH CONTINUES TO BUILD IN FROM THE NORTH. MONDAY INTO
TUESDAY WILL BRING THE UPPER RIDGE EASTWARD IN A WEAKENING STATE.
THE SURFACE HIGH WILL SHIFT SLIGHTLY EASTWARD AS WELL BUT NOT ENOUGH
FOR SUFFICIENT MOISTURE FLUX LOCALLY. TEMPERATURES NEAR CLIMO EARLY
IN THE PERIOD WITH JUST A VERY SLOW RISE THROUGHOUT AS A RESULT OF
SOLAR MODERATION AS OPPOSED TO ANY THERMAL ADVECTION.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 14Z...FRONT IS LINGERING OVER THE SOUTHERN PORTION OF THE
CWA. PWATS HAVE COME DOWN...BUT ARE STILL RANGING IN THE 1.5-1.9"
RANGE. SHOULD SEE SOME ISOLATED CONVECTION NEAR THE MYRTLES AROUND
MAX HEATING. WINDS WILL BE PREDOMINATELY NORTHEAST OVER THE
NORTHERN PORTION OF THE CWA...AND VARIABLE OVER THE SOUTHERN
PORTION. THE COAST WILL LIKELY SEE A SEA BREEZE RESULTANT BY
18-19Z. TONIGHT...GOOD RADIATIONAL COOLING CONDITIONS WILL BRING
IN THE CHANCE FOR FOG AFTER 08Z. INLAND TERMINALS STAND THE BEST
CHANCE FOR IFR CONDITIONS.
EXTENDED OUTLOOK...MORNING FOG/STRATUS IS POSSIBLE THROUGH THE
EXTENDED PERIOD. OTHERWISE VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...WEAK COLD FRONT HAS MOVED SOUTH AND EAST
OF THE OF THE WATERS THIS MORNING AND WILL BE FOLLOWED BY WEAK
OFFSHORE FLOW. DIFFUSE GRADIENT BEHIND THE FRONT WILL ALLOW
DEVELOPMENT OF AFTERNOON SEA BREEZE. THIS WILL LEAD TO STRONGEST
WINDS OVER THE NEAR SHORE WATERS WITH LIGHTER WINDS AWAY FROM
SHORE. SPEEDS WILL STRUGGLE TO EXCEED 10 KT BUT ISOLATED GUSTS IN
THE AFTERNOON TO 15 KT WILL BE POSSIBLE. DISSIPATION OF SEA BREEZE
CIRCULATION THIS EVENING WILL RESULT IN WINDS BECOMING LIGHT AND
VARIABLE OVERNIGHT. SEAS WILL RUN 2 TO 3 FT THROUGH THE PERIOD.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...EVEN THOUGH A FRONT WILL BE STALLED AND
WEAKENING NOT FAR TO THE SOUTH ON THURSDAY THE FLOW WILL TURN BACK
AROUND TO A SOUTHERLY DIRECTION AS SURFACE TROUGHINESS DEVELOPS JUST
INLAND FROM THE COAST. IT WILL BE A VERY LIGHT FLOW WITH SPEEDS
GENERALLY CAPPED AT 10KT RESULTING IN 2 FT SEAS. A FAIRLY QUICK VEER
TO THE NORTH IS SLATED FOR THURSDAY NIGHT ALTHOUGH SOME LESS FAVORED
MODEL SOLUTIONS ARE SLOWER. A RELATIVELY STRONG HIGH WILL BUILD IN
BEHIND THE THURSDAY NIGHT FRONT AND WIND SPEEDS MAY INCREASE A
CATEGORY OR MORE BUILDING SEAS INTO THE 2 TO 4 FT RANGE...A LITTLE
LOWER OVER SRN ZONES.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...ANY RESIDUAL VESTIGE OF THE SURGE FROM THE
SHORT TERM SHOULD QUICKLY ABATE AS SATURDAY WEARS ON AS HIGH
PRESSURE BECOMES CENTERED OFF OF NEW ENGLAND/MID ATLANTIC AND
EXTENDS RIDGE AXIS INTO THE CAROLINAS. WINDS WILL BE ONSHORE EITHER
E OR NE AND FALL TO 10 KTS ALLOWING SEAS TO SETTLE TO 2 FT. A PIECE
OF THE HIGH BREAKS OFF AND STAYS BEHIND ACROSS THE CAROLINAS ON
SUNDAY CONTINUING THE TREND OF VERY LIGHT ONSHORE WIND AND SEAS
CAPPED AT 2 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...8
NEAR TERM...8
SHORT TERM...MBB
LONG TERM...MBB
MARINE...III/8/MBB
AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
950 AM EDT WED SEP 4 2013
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST TODAY. A DRY
COLD FRONT WILL MOVE THROUGH THE REGION LATE THURSDAY AND THURSDAY
NIGHT... AND THEN STRONGER HIGH PRESSURE WILL BUILD INTO THE AREA
FRIDAY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM WEDNESDAY...
LATEST SURFACE MAP AND SATELLITE IMAGERY SHOW THE PRIMARY COLD FRONT
(WIND SHIFT) LOCATED WELL SOUTH OF NC... ACROSS CENTRAL GA... WITH A
FEW SUBTLE SECONDARY BOUNDARIES DROPPING SOUTH AND SSW THROUGH NC.
ONE PRONOUNCED BOUNDARY APPEARS TO REPRESENT THE OUTFLOW FROM
EARLY-MORNING STORMS OVER SE VA... AND THIS BOUNDARY IS NOW TRACKING
SSW THROUGH THE SRN COASTAL PLAIN AND ERN SANDHILLS... WITH PATCHY
STRATOCUMULUS IN ITS WAKE OVER THE NORTH-CENTRAL AND NE CWA. DEW
POINTS HAVE DROPPED INTO THE 60-65 DEGREE RANGE OVER MUCH OF THE NRN
AND WRN CWA BUT REMAINS IN THE UPPER 60S TO LOWER 70S DOWN EAST...
AND IT IS IN THIS AREA OVER THE SOUTHEAST CWA WHERE MLCAPE IS
FORECAST TO PEAK NEAR 1500 J/KG. CONVECTION-ALLOWING MODELS DO
DEPICT SCATTERED CONVECTION OVER SOUTHEAST AND EXTREME SOUTH-CENTRAL
NC THIS AFTERNOON AND EVENING... REASONABLE GIVEN THE PRESENCE OF
ABUNDANT LOW LEVEL MOISTURE (DESPITE DRYING ALOFT NOTED ON WATER
VAPOR AND BLENDED TPW IMAGERY) AND MARGINAL 15-20 KTS OF BULK SHEAR.
THE HRRR SUGGESTS THAT WE`LL SEE AN INLAND-MOVING SEA BREEZE AS WELL
WHICH COULD PROVIDE AN ADDITIONAL FOCUS FOR LIFT. WILL INCLUDE A
VERY SMALL CHANCE OF A SHOWER OVER THE EXTREME SOUTHEAST... BUT
OTHERWISE EXPECT DRY WEATHER. THICKNESSES ARE EXPECTED TO STAY NEAR
NORMAL OVER MUCH OF THE AREA EXCEPT SLIGHTLY ABOVE NORMAL IN THE
SOUTHEAST... AND FORECAST HIGHS CLOSE TO NORMAL -- IN THE MID-UPPER
80S -- LOOK VERY REASONABLE. -GIH
MOSTLY CLEAR TONIGHT. LOWS IN THE LOWER 60S NW TO UPPER 60S SE. -BL
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
SHORTWAVE ENERGY DIVING SOUTHEASTWARD DOWN THE BACKSIDE OF THE UPPER
VORTEX OVER QUEBEC WILL SWING THROUGH THE NORTHEAST US AND SOUTHERN
NEW ENGLAND STATES ON THURSDAY/THURSDAY NIGHT. A SECONDARY SURGE OF
DRY-COOLER AIR WILL BEGIN TO SPREAD SOUTH AS SFC HIGH PRES OVER THE
GREAT LAKES BUILDS INTO THE MID-ATLANTIC STATES...REACHING CENTRAL
NC THURSDAY THURSDAY NIGHT/EARLY FRIDAY BY MEANS OF A DRY BACK-DOOR
COLD FRONTAL PASSAGE INTO THE AREA THURSDAY EVENING.
SEASONABLE HIGHS AHEAD OF THE FRONT THURSDAY AFTERNOON WITH
HIGHS IN THE MID 80S NORTH TO NEAR 90 SOUTH. LOWS IN THE LOWER 60S
NORTH TO MID 60S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 245 AM WEDNESDAY...
OVERALL THE LONG TERM PERIOD WILL BE CHARACTERIZED BY MOSTLY DRY
CONDITIONS AS THE MAIN STORM TRACK REMAINS WELL NORTH OF THE REGION
AND SEVERAL ROUNDS OF SURFACE HIGH PRESSURE AND WEAK FLOW ALOFT
AROUND A BROAD TROUGH SITUATED ACROSS THE EASTERN CONUS DOMINATES
THE WEATHER ACROSS CENTRAL NC. ANOTHER REINFORCING SHOT OF STRONGER
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FRIDAY INTO SATURDAY
BEHIND A FRONT WHICH IS PROGGED TO MOVE THROUGH THE REGION LATE
THURSDAY. WITH THIS RENEWED HIGH PRESSURE BUILDING IN...FRIDAY AND
SATURDAY ARE EXPECTED TO BE MOSTLY DRY.
THE HIGH IS THEN PROGGED TO SHIFT OFFSHORE BY LATE SATURDAY INTO
EARLY SUNDAY...BUT WITH ONLY MINIMAL MOISTURE RETURN...THE DRY
CONDITIONS ARE EXPECTED TO PERSIST. THEN...ANOTHER FRONT IS PROGGED
TO MOVE ACROSS THE AREA ON MONDAY...WITH YET ANOTHER RENEWED SURFACE
HIGH BUILDING INTO THE REGION FOR EARLY NEXT WEEK. FOR MONDAY...WILL
KEEP THE FORECAST DRY FOR NOW...BUT THERE COULD BE SOME ISOLATED
ACTIVITY...ESPECIALLY IF THE FRONT MOVES THROUGH DURING A FAVORABLE
TIME. IN ADDITION...WITH THE LATEST HIGH CENTERED SLIGHTLY FURTHER
TO THE NORTH THAN PREVIOUS ONES AND THEREFORE MORE IN THE WAY OF
EASTERLY FLOW...MOISTURE IS PROGGED TO GRADUALLY INCREASE THROUGH
EARLY NEXT WEEK. HOWEVER...THE EAST COAST TROUGH ALOFT IS FINALLY
EXPECTED TO BE REPLACED BY AN EASTWARD PROGRESSING UPPER LEVEL RIDGE
BY THE EARLY TO MIDDLE PART OF NEXT WEEK...WHICH MAY WORK AGAINST
ANY CONVECTIVE DEVELOPMENT. WITH ALL OF THIS IN MIND...WITH MAINTAIN
A DRY FORECAST THROUGH THE REMAINDER OF THE LONG TERM PERIOD...BUT
THAT IS NOT TO SAY THERE COULD BE SOME ISOLATED DIURNAL TYPE
ACTIVITY TO START NEXT WEEK. TEMPS WILL BE TIED TO THE MULTIPLE
FRONTAL PASSAGES DURING THE PERIOD...BUT WILL GENERALLY BE NEAR TO
SLIGHTLY BELOW NORMAL THROUGHOUT THE ENTIRE PERIOD.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 700 AM WEDNESDAY...
24-HR TAF PERIOD:
PATCHY FOG IN THE EAST SHOULD LIFT AND MIX OUT SHORTLY AFTER
DAYBREAK. THEREAFTER WEAK SURFACE HIGH PRESSURE WILL BUILD INTO THE
AREA THROUGH THE AFTERNOON...SECURING DRY VFR CONDITIONS THROUGH THE
REMAINDER OF THE PERIOD. CLEAR SKIES TONIGHT COULD SUPPORT SUB-VFR
CONDITIONS IN FOG AND/OR STRATUS...MAINLY ACROSS EASTERN TERMINALS.
LOOKING AHEAD:
ASIDE FROM EARLY MORNING FOG/STRATUS...EXPECT VFR CONDITIONS
THROUGH SUNDAY AS HIGH PRESSURE BUILDS INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL/GIH
NEAR TERM...HARTFIELD/CBL
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
645 AM EDT WED SEP 4 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE OHIO VALLEY TODAY. ON
THURSDAY...A MOISTURE-STARVED COLD FRONT WILL MOVE SOUTH THROUGH THE
REGION...PRODUCING NO PRECIPITATION. ANOTHER AREA OF HIGH PRESSURE
WILL MOVE IN BEHIND THE FRONT...WITH TEMPERATURES REMAINING SLIGHTLY
COOLER THAN NORMAL FOR FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL MAINTAIN ITS CONTROL OVER THE WEATHER
TODAY...WITH VERY TRANQUIL CONDITIONS EXPECTED. RH THROUGH THE
COLUMN IS VERY LOW (ESPECIALLY AROUND 850MB...ABOUT 10 PERCENT).
THE SKY GRIDS HAVE BEEN KEPT IN THE SUNNY CATEGORY...THOUGH THERE
MAY BE VERY ISOLATED WEAK CUMULUS DEVELOPMENT...OR A FEW PATCHES
OF VERY THIN CIRRUS.
ALTHOUGH FULL SUN IS EXPECTED...MIXING MAY BE SOMEWHAT LIMITED
WITH THE LIGHT WINDS...AND MODEL SOUNDINGS INDICATE MAKING IT UP
TO ABOUT 870MB-860MB. THERE IS SOME WARM ADVECTION EXPECTED TO
OCCUR ALOFT (WNW FLOW OUT OF THE BIG RIDGE TO THE WEST)...SO TEMPS
SHOULD CLIMB A FEW DEGREES FROM YESTERDAY.
JUMPING BACK TO THE VERY NEAR-TERM...THERE DOES APPEAR TO BE SOME
FOG POTENTIAL EARLY THIS MORNING. TEMPERATURES RE RADIATING
SIGNIFICANTLY AND RIVER VALLEYS ARE ALREADY BEGINNING TO FILL IN
WITH LOWERED VISIBILITIES. IN ADDITION...THE HRRR DEPICTS A VERY
LARGE AREA OF DENSE FOG DEVELOPING OVER NORTHERN INDIANA. NONE OF
THIS ADDS UP TO WIDESPREAD SIGNIFICANT FOG OVER THE ILN CWA...BUT
SOME PATCHY FOG HAS BEEN INCLUDED IN THE NORTHWEST CWA AND IN THE
RIVER VALLEYS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
THE SHORT TERM OF THE FORECAST WILL BEGIN WITH THE CWA JUST AHEAD
OF A COLD FRONT MOVING IN FROM THE NORTH...AS THE WEDNESDAY HIGH
PRESSURE SHUNTS WESTWARD AND WEAKENS. THE FRONT IN QUESTION WILL
BE FAR REMOVED FROM ITS SOURCE IN A MID-LEVEL TROUGH CROSSING EAST
OF JAMES BAY. THE FRONT WILL BE MOVING INTO THE VERY DRY AIR MASS
OVER THE OHIO VALLEY. THE MODEL CONSENSUS ON LOW AND MID LEVEL RH
HAS COME UP SLIGHTLY FROM YESTERDAY...BUT THERE IS STILL LITTLE
TO INDICATE THAT MEASURABLE PRECIPITATION WILL OCCUR. AT
MOST...SOME SPRINKLES OR VERY LIGHT SHOWERS MAY BE POSSIBLE...BUT
THIS WILL NOT BE INCLUDED IN THE FORECAST. THE FRONT WILL BE
ACCOMPANIED BY A MARKED NNE WIND SHIFT...WITH A MASSIVE AMOUNT OF
NEGATIVE THETA-E ADVECTION. A NNE-TO-SSW GRADIENT HAS BEEN USED
FOR THE MAX TEMP GRIDS ON THURSDAY...ACCOUNTING FOR THE
FRONT...THOUGH THE TIMING OF THE TEMPERATURE CURVE STILL APPEARS
GENERALLY DIURNAL.
AFTER THE FRONT CROSSES THROUGH ON THURSDAY...HIGH PRESSURE IS
EXPECTED TO BUILD IN FROM THE NORTH ON THURSDAY NIGHT AND FRIDAY.
ALTHOUGH WINDS MAY NOT GO COMPLETELY CALM THURSDAY NIGHT...THE AIR
MASS WILL BE DRYING AND CAPABLE OF SOME RATHER COOL TEMPERATURES
(LOWER 50S AND UPPER 40S). THE ADVECTION PATTERN WILL REMAIN
NEUTRAL TO SLIGHTLY COOL ON FRIDAY...WITH THE OVERALL AIR MASS NOT
MODIFYING MUCH FROM THE COOL STARTING POINT. SO...DESPITE QUITE A
BIT OF SUN EXPECTED...MAX TEMPS WILL NOT BE ESPECIALLY HIGH (MID
70S IN CENTRAL OHIO TO AROUND 80 IN THE SW). THIS IS WARMER THAN
THE NAM BUT NOT AS WARM AS GFS/ECMWF 850MB TEMPS WOULD OTHERWISE
SUPPORT.
THE SURFACE HIGH WILL BE MOVING EAST OF THE REGION BY
SATURDAY...AS RIDGING BEGINS TO BUILD IN ALOFT. THIS WILL PUT THE
CWA IN A REGIME OF NORTHWEST FLOW ALOFT (EVENTUALLY SPILLING IN
SOME CLOUDS) AND SW FLOW AT THE SURFACE (WITH TEMPERATURES AND
DEWPOINTS BEGINNING TO RISE AGAIN).
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
STARTING ON SATURDAY...SHORT WAVE ENERGY ROUNDING THE CREST OF
THE UPPER RIDGE WILL COMBINE WITH LIMITED SURFACE CONVERGENCE AND
MODERATE INSTABILITY TO PRODUCE A CHANCE OF THUNDERSTORMS FROM
TIME TO TIME. THE BEST CHANCE APPEARS TO BE ON SUNDAY...WHEN A
FRONTAL BOUNDARY SAGGING FROM THE NORTH MAY BE THE FOCUS FOR
CONVECTIVE DEVELOPMENT. WITH NO STRONG FORCING INDICATED FOR THE
REST OF THE PERIOD...KEPT POPS UNDER THE 25 PERCENT THRESHOLD
REQUIRED TO SHOW UP IN THE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE GREAT LAKES AND THE OHIO VALLEY WILL REMAIN UNDER A NORTHWEST
FLOW PATTERN ALOFT THROUGH THE TAF PERIOD. AT THE SURFACE...HIGH
PRESSURE ORIENTED OVER THE OHIO VALLEY WILL MOVE SOUTH AND
SOUTHWEST OF THE RIVER BY TONIGHT AS A WEAK COLD FRONT PUSHES IN
FROM THE NORTH. THE FRONT SHOULD BE SOUTH OF THE RIVER NEAR 12Z
THURSDAY. THE FRONT IS MOISTURE STARVED...SO ONLY A MIX OF HIGH
CLOUDS AND SOME STRATOCUMULUS CLOUDS ARE EXPECTED.
IN THE MEANTIME...MAINLY CLEAR SKIES WILL DOMINATE THROUGH THE
REMAINDER OF THE MORNING HOURS AND INTO THE DAYTIME. RIVER FOG
NEAR KLUK AND PATCHY FOG/MIST AT KILN/KLCK SHOULD DISSIPATE
QUICKLY BETWEEN 13Z AND 14Z.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HATZOS
NEAR TERM...HATZOS
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
631 AM CDT WED SEP 4 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CDT WED SEP 4 2013
CURRENTLY SEEING SOME SCATTERED SHOWERS AND A FEW THUNDERSTORMS
ACROSS SOUTH CENTRAL SOUTH DAKOTA. IN GENERAL EXPECT THE COVERAGE OF
THESE SHOWERS TO DECREASE DURING THE MORNING AS WE LOSE THE LOW
LEVEL JET. HOWEVER...A WEAK MID LEVEL WAVE WILL REMAIN IN THE AREA
THROUGH THE DAY...WITH DECENT MID LEVEL MOISTURE AND SOME THETAE
ADVECTION. THUS WILL KEEP SLIGHT CHANCE POPS THROUGH THE
DAY...MAINLY FROM JUST EAST OF THE INTERSTATE 29 CORRIDOR AND POINTS
WEST. DRY AIR IN THE LOWER LEVELS SHOULD MAKE IT TOUGH FOR MUCH OF
THIS MID LEVEL ACTIVITY TO REACH THE GROUND...BUT DO THINK A FEW
SHOWERS ARE POSSIBLE. THE HRRR IS MOST AGGRESSIVE WITH THE
ACTIVITY...AND WHILE IT SEEMS OVERDONE...IT DOES GIVE ANOTHER REASON
TO KEEP THE SLIGHT CHANCE POPS. INSTABILITY IS MARGINAL...BUT GIVEN
THE HIGH BASED NATURE OF THESE STORMS THERE MAY BE JUST ENOUGH TO
GET A LIGHTNING STRIKE OR TWO WITH THE SHOWERS EVERY ONCE IN A
WHILE...SO KEPT THUNDER IN FOR NOW. HIGH TEMPERATURES TODAY SHOULD
BE IN THE 80S...WITH THE CLOUD COVER PREVENTING FULL HEATING FOR
MOST OF THE AREA. MUCH OF THE SAME TONIGHT...WITH THE MID LEVEL WAVE
IN THE VICINITY...EXPECTING A MOSTLY CLOUDY NIGHT. COULD SEE A
SLIGHT UPTICK IN SHOWER ACTIVITY THE FIRST PORTION OF THE NIGHT AS
THE LOW LEVEL JET GETS GOING...BUT NOT REAL CONFIDENT IN THAT. THUS
WILL KEEP JUST SLIGHT CHANCE POPS FOR NOW. EITHER WAY NOT EXPECTING
MUCH. DID RAISE LOWS SOME WITH THE NEWER GUIDANCE COMING IN A BIT
WARMER...SUGGESTING ANY COOLER AND DRYER LOW LEVEL AIR STAYS
NORTHEAST OF THE CWA. GENERALLY LOOKING FOR LOW TO MID 60S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 4 2013
AN UPPER LEVEL WAVE AND A WEAK MID LEVEL BOUNDARY COULD SPARK A FEW
SHOWERS OVER THE FAR EASTERN CWA ON THURSDAY BUT WITH FAIRLY DRY LOW
LEVELS AND WEAK MID LEVEL INSTABILITY NO PLAN TO ADD ANY POPS AS
WHATEVER COULD DEVELOP WOULD REMAIN ON THE LIGHT SIDE. AS THE WAVE
EXITS WILL BE A BIT OF A EASTERLY COMPONENT TO THE WIND SO WHILE THE
DAY WILL BE WARM EXPECT NO MAJOR MIXING. HIGHS MAINLY IN THE LOWER
TO MID 80S.
THURSDAY NIGHT INTO FRIDAY WILL SEE A TIGHTENING OF THE GRADIENT AND
AN INCREASE IN THE LOW LEVEL TEMPERATURE FIELD. THIS WILL LEAD
TOWARDS WARM LOWS IN THE MID AND UPPER 60S AND HIGHS ON FRIDAY WELL
INTO THE 90S WITH SOMETHING AROUND 100 POSSIBLE IN CENTRAL SOUTH
DAKOTA.
A STRONG RIDGE OF HIGH PRESSURE WILL BE IN PLACE FOR MUCH OF THE
PERIOD...THEN SOME HINTS THAT IT SHOULD BREAK DOWN A BIT EARLY NEXT
WEEK AS A WEAK SHORTWAVE MOVES THROUGH THE NORTHERN ROCKIES AND INTO
THE NORTHERN PLAINS. OVERALL THE MODELS ARE IN PRETTY GOOD AGREEMENT
WHICH SUGGESTS VERY WARM READINGS SATURDAY THROUGH MONDAY...WITH THE
HOTTEST TEMPERATURES LIKE FRIDAY AND SATURDAY AHEAD OF A WEAK
BOUNDARY THAT IS PROGGED TO LEAK SOUTHWARD INTO THE AREA. NOT MUCH
PUNCH FROM THIS BOUNDARY AS THE WAVE THAT IS FORCING IT SOUTH IS
MOVING SOUTHEAST THROUGH THE GREAT LAKES REGION. THE RIDGE
REESTABLISHES AGAIN ON MONDAY AS THE WEAK WAVE MOVES ONTO THE PLAINS
AND TRIES TO BRING A BOUNDARY INTO THE AREA ON TUESDAY. IF THIS WAVE
IS A LITTLE SLOWER TUESDAY COULD PROVE TO BE VERY WARM AS WELL. WILL
CONFINE POPS TO THE TIMING OF THE TWO FRONTS WHICH SHOULD MAINLY BE
SATURDAY NIGHT INTO SUNDAY AND MONDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 629 AM CDT WED SEP 4 2013
MAINLY VFR CONDITIONS THROUGH THE PERIOD. COULD BE A FEW ISOLATED
SHOWERS OR THUNDERSTORMS TODAY INTO TONIGHT. BUT COVERAGE IS EXPECTED
TO BE TOO SPARSE TO WARRANT MENTION IN THE TAFS AT THIS TIME.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
605 AM CDT WED SEP 4 2013
.DISCUSSION...
SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...
FCST SOUNDINGS SHOW LOWER PW VALUES THAN YESTERDAY WITH VALUES
PEAKING NEAR 1.5 INCHES OVER THE NORTH AND 1.9 INCHES SOUTH.
DAYTIME HEATING AND THE SEA BREEZE LOOK TO BE THE CATALYST FOR
SHRA/TSRA DEVELOPMENT LATER TODAY. THE RAP AND HRRR SUPPORT SCT
SHRA/TSRA OVER MAINLY THE SOUTHERN HALF OF THE AREA TODAY. OUTSIDE
OF AREAS OF CONVECTION...VFR CONDS EXPECTED TODAY WITH GENERALLY
LIGHT WINDS. 43
&&
.PREV DISCUSSION... /ISSUED 452 AM CDT WED SEP 4 2013/
DISCUSSION...
EARLIER SHOWERS NEAR COLLEGE STATION HAVE WEAKENED AND MOVED OUT
OF THE AREA TONIGHT. THE BOUNDARY THAT WAS DRAPED ACROSS THE
NORTHERN ZONES YESTERDAY HAS ALREADY STARTED TO WASH OUT. AT 200
MB THE UPPER LEVEL RIDGE HAS STARTED TO MOVE EASTWARD PUSHING THE
BEST UPPER LEVEL DIFFLUENCE TO THE EAST AS WELL. THE RIDGE AT 500
MB HAS ALSO STARTED TO STRENGTHEN WITH HEIGHTS RISING. HEIGHTS
ACROSS SOUTHEAST TEXAS HAVE ALSO RISEN SOME. MOISTURE SHOULD CONTINUE
TO FALL TODAY ESPECIALLY IN THE NORTHERN ZONES. FORECAST SOUNDINGS
SHOW PWATS DROPPING TO AROUND 1.6" AT KCLL. CURRENT PWATS (AS PER
GPS MET) STILL SHOW THE DRIER AIR HUNG UP FURTHER NORTH THOUGH.
MODELS SEEM TO HAVE BEEN TO AGGRESSIVE WITH BRINGING THE DRIER AIR
DOWN THE LAST COUPLE DAYS THOUGH. GIVEN THE LACK OF FOCUS FOR LIFT
AND FORECASTED LOWER MOISTURE LEVELS THE COVERAGE OF SHOWERS AND
THUNDERSTORMS SHOULD BE LESS TODAY. MODELS STILL HINTING AT PRECIP
FORMING ALONG THE SEA BREEZE TODAY WHICH SEEMS REASONABLE GIVEN
MOISTURE STILL HANGING AROUND AT COAST. FURTHER NORTH AT KCLL
THOUGH FORECAST SOUNDINGS REVEAL A CAP IN PLACE WHICH SHOULD KEEP
PRECIP LIMITED IN THE NORTHERN ZONES.
THE TROPICAL WAVE CURRENTLY LOCATED NEAR THE YUCATAN IS EXPECTED
TO DRIFT WESTWARDS AND APPROACH NORTHERN MEXICO FRIDAY MORNING.
THE GFS BRINGS THE WAVE AXIS CLOSER TO BROWNSVILLE WHILE THE ECMWF
PUSHES THE WAVE FURTHER SOUTH. AS THE WAVE MOVES WESTWARD THE 500
MB RIDGE WILL BE PUSHING EASTWARD AS AN UPPER LEVEL LOW MOVES
INTO THE PACIFIC NORTHWEST. THE RIDGE WILL PRODUCE A GRADIENT OF
MOISTURE AS CAN BE SEEN IN THE GFS PWAT FIELD. FORECASTED PWATS
OF AROUND 1.00" CAN BE FOUND AT KFWD WHILE AROUND 2.00" AT KCRP.
HOWEVER THIS SHARP GRADIENT SETS UP WILL DETERMINE HOW THE PRECIP
FIELD SETS UP. AS OF NOW IT LOOKS THAT THE SOUTHERN ZONES WILL GET
SOME RAIN BUT A SLIGHT SOUTHERLY DRIFT OF THE UPPER LEVEL RIDGE
COULD EASILY CHANGE THIS.
BY TUESDAY THE UPPER LEVEL RIDGE CONTINUES TO PUSH EASTWARD
ALLOWING ANOTHER TROPICAL WAVE TO WORK ITS WAY INTO SOUTHEAST
TEXAS. THE POSITION OF THE RIDGE WILL AGAIN HELP DETERMINE THE
PRECIP FIELD. THE GFS SHOWS A STRONGER AND MORE PROGRESSIVE UPPER
LEVEL RIDGE WHILE THE ECMWF IS SLIGHTLY SLOWER WITH THE BRINGING
THE RIDGE EASTWARD. 23
MARINE...
A RELATIVELY WEAK PRESSURE GRADIENT WILL REMAIN IN PLACE TODAY WITH
LIGHT ONSHORE WINDS EXPECTED. A SERIES OF WEAK EASTERLY WAVES WILL
MOVE INTO MEXICO WITH THE FIRST WEAKER WAVE MOVING TOWARD THE
MEXICAN COAST ON FRIDAY AND A SECOND STRONGER WAVE MOVING INLAND ON
SUNDAY. WINDS OVER THE GULF WILL BRIEFLY INCREASE AS THESE WAVES
MOVE INLAND BUT THE STRONGER SUSTAINED WINDS SHOULD REMAIN SOUTH OF
THE COASTAL WATERS. UNSETTLED WEATHER WITH PERIODS OF SHOWERS AND
THUNDERSTORMS WILL PERSIST OVER THE MARINE AREAS THROUGH THE
WEEKEND. WINDS/SEAS OBVIOUSLY HIGHER NEAR STORMS. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 76 98 75 98 / 20 10 20 10 20
HOUSTON (IAH) 99 76 97 76 96 / 30 10 20 10 20
GALVESTON (GLS) 90 81 90 80 89 / 20 20 30 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...23
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
1005 AM PDT WED SEP 4 2013
.SYNOPSIS...
HOT AND MUGGY CONDITIONS WILL REDEVELOP OVER SOUTHERN CALIFORNIA FOR
THE END OF THE WORK WEEK...AS HIGH PRESSURE STRENGTHENS INTO THE
REGION. A SHALLOW MARINE LAYER WILL HELP MODERATE TEMPERATURES
ALONG THE COAST THOUGH...WHILE INLAND AREAS RANGE 5 TO 10 DEGREES
ABOVE NORMAL. SUBTROPICAL MOISTURE WILL ALSO CONTINUE TO SPREAD
INTO THE SOUTHLAND THROUGH THE WEEK...WITH THE THREAT OF AFTERNOON
SHOWERS AND THUNDERSTORMS CONTINUING IN THE MOUNTAINS AND DESERTS.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
TODAY...
MADE SOME CHANGES TO THE GRIDS AND SENT UPDATED FORECASTS TO SHOW
MORE AREAL COVERAGE OF THUNDERSTORMS...A LITTLE FURTHER WEST OF
MOUNTAINS DUE TO SHIFT IN TRANSPORT WINDS TO THE SOUTHEAST AND
APPROACH OF OUTFLOW BOUNDARY FROM MASSIVE NOT SO MESOSCALE
CONVECTIVE COMPLEX THAT OCCURRED OVER SONORA...SINALOA...GULF OF
CALIFORNIA...AND BAJA CALIFORNIA...AND HAS NOW TURNED THE CORNER AND
HEADING NORTHWEST. HAD A LINE OF ALTOCUMULUS CASTELLANUS ALONG THE
PENINSULAR RIDGE LINE AT SUNRISE...AT 0935 PDT COULD VISUALLY SEE
THE OVERSHOOTING TOPS IN REFORMED COMPLEX MOVING INTO IMPERIAL
COUNTY. THE 04/15Z HRRR MODEL HAS FINALLY PICKED UP ON THIS...NONE
OF THE OTHER MODELS DID. WORSE YET IT SHOWS THE THUNDERSTORMS
DEVELOPING ALONG THE ELSINORE CONVERGENCE ZONE THIS AFTERNOON...SO
MAY NEED ANOTHER UPDATE TO SPREAD THE THUNDERSTORMS EVEN FURTHER
WEST. THE GOOD NEWS...IF ANY ...IN ALL THIS IS THE AIR MASS IN THE
-10C TO -20C LAYER IS DRIER THAN YESTERDAY AND THE OVERALL COLUMN
LOOKS DRIER ALTHOUGH THE PRECIPITABLE WATER AND THE CAPE VALUES WERE
ESSENTIALLY THE SAME...SO AT LEAST INITIALLY THROUGH EARLY AFTERNOON
THE ICE/HAIL PRODUCTION SHOULD BE LESS...AND THE WIDESPREAD HEAVY
RAIN LEADING TO FLASH FLOODING WOULD BE LESS...AGAIN ASSUMING NO AIR
MASS CHANGE THIS AFTERNOON...WHICH IS LOOKING LIKE A SHAKY
ASSUMPTION THIS MORNING.
OTHERWISE THE FORECAST LOOKS GOOD ESPECIALLY WITH THE WARMER
TEMPERATURES TODAY AND AGAIN THURSDAY. SO FAR TEMPS ARE FORECAST
JUST BELOW HEAT ADVISORY CRITERIA.
EXCERPTS FROM THE EARLY MORNING DISCUSSION FOLLOW...
WATER VAPOR IMAGERY CONTINUES TO SHOW AN ELONGATED TROUGH OF LOW
PRESSURE ALONG THE WEST COAST AND HIGH PRESSURE CENTERED OVER
COLORADO. AT THIS TIME...SOUTHERN CALIFORNIA REMAINS UNDER THE
INFLUENCE OF THIS HIGH PRESSURE SYSTEM...WHICH WILL GRADUALLY
STRENGTHEN OVER THE NEXT COUPLE OF DAYS. AS A RESULT...HOT
CONDITIONS WILL DEVELOP ACROSS THE INLAND AREAS...WITH TEMPERATURES
RANGING 5 TO 10 DEGREES ABOVE NORMAL. A FEW OF THE WARMEST SPOTS
MAY BE EVEN HOTTER...TOPPING OUT AT 15 DEGREES ABOVE NORMAL. THAT
BEING SAID...IT DOES NOT APPEAR THAT ANY RECORDS WILL BE BROKEN AT
THIS TIME...SO WILL JUST HIGHLIGHT THE HEAT WITH A SPECIAL WEATHER
STATEMENT. THE OTHER MAIN CONCERN FOR TODAY WILL BE WITH THE THREAT
OF AFTERNOON SHOWERS AND THUNDERSTORMS IN THE MOUNTAINS AND
DESERTS...
THE OVERALL PATTER WILL CHANGE OVER THE NEXT COUPLE OF DAYS...SO HOT
CONDITIONS WILL LIKELY PREVAIL ACROSS THE INLAND AREAS...WITH
ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS POSSIBLE IN THE
MOUNTAINS AND DESERTS. THE TROUGH WILL THEN MOVE INLAND ACROSS THE
THE PACIFIC NORTHWEST LATE FRIDAY AND INTO THE WEEKEND. THIS WILL
BRING SOME RELIEF TO THE HOT WEATHER...AS A GRADUAL COOLING TREND
DEVELOPS. HOWEVER...THE MODELS CONTINUE TO INDICATE THE POTENTIAL
FOR AFTERNOON SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND
DESERTS. THE MODELS START TO DEVIATE A BIT FOR EARLY NEXT
WEEK...BUT IT APPEARS THAT AN UPPER LEVEL DISTURBANCE WILL DEVELOP
OFF OR ALONG THE SOUTHERN CALIFORNIA COAST. THE PLACEMENT OF THIS
DISTURBANCE WILL ULTIMATELY DICTATE OUR WEATHER...BUT FOR NOW...WILL
CONTINUE WITH THE THREAT OF AFTERNOON SHOWERS AND THUNDERSTORMS OVER
THE MOUNTAINS AND DESERTS AND MORE SEASONAL TYPE TEMPERATURES
PREVAILING.
&&
.AVIATION...
041515Z...COAST/VALLEYS...FEW-SCT CLDS AOA 9000 FT MSL DURING THE
1900-05/0300 UTC TIME-PERIOD. ALSO...SLIGHT CHANCE OF FOG REACHING
KSAN...KCRQ...AND/OR KSNA DURING THE 05/1100-1500 UTC
TIME-FRAME...BUT CONFIDENCE IS LOW. OTHERWISE...MOSTLY UNRESTRICTED
VIS/CIGS THROUGH THURSDAY MORNING.
MTNS/DESERTS...SCATTERED THUNDERSTORMS DURING THE 1800-05/0300 UTC
TIME-PERIOD WITH BASES 7000-10000 FT MSL AND CB TOPS TO 45000 FT
MSL...RESULTING IN LOCAL VIS AOB 2SM IN HEAVY RAIN...SMALL
HAIL...AND POSSIBLE STRONG UP/DOWNDRAFTS. OTHERWISE...UNRESTRICTED
VIS THROUGH THURSDAY MORNING.
&&
.FIRE WEATHER...
NEAR RECORD HIGH TEMPERATURES BUT ENOUGH MOISTURE IN AIR TO KEEP MIN
RELATIVE HUMIDITY VALUES AT OR ABOVE 25 PERCENT. MARINE LAYER DEPTH
WILL GENERALLY STAY NEAR OR BELOW 700 FEET. THREAT OF DRY LIGHTING
WEST OF MOUNTAINS THIS AFTERNOON...ALTHOUGH THAT MAY BE JUST A
TEMPORARY TRANSITION TO WET THUNDERSTORMS DURING THE LATER
AFTERNOON. ISSUED UPDATE TO FIRE WEATHER PLANNING FORECAST TO SHOW
MORE THUNDERSTORM COVERAGE...HIGHER LAL...THREAT OF HEAVY RAIN
OVER/NEAR MOUNTAINS AND DESERTS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC/FIRE WEATHER...JT/BALFOUR
AVIATION/MARINE...HARRISON/PIERCE
SHORT TERM WARNINGS...JJT/JT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
454 PM CDT WED SEP 4 2013
.DISCUSSION...
300 PM CDT
THE FORECAST CHALLENGES ARE MAINLY TEMPERATURES AS SUMMER LOOKS TO
WIN OUT OVER AUTUMN IN THE EARLY GOING OF SEPTEMBER.
SYNOPSIS...IMPRESSIVELY DEEP UPPER TROUGH OVER EASTERN CANADA IS
BEING REINFORCED THIS AFTERNOON WITH A VIGOROUS JET DIVING INTO
THE UPPER GREAT LAKES. AS A GEE-WHIZ AND A SIGN OF THE CHANGE IN
SEASONS...NOT HERE YET BUT UP NORTH...850MB TEMPS AT CWZC ON THE
SOUTHERN END OF JAMES BAY DROPPED FROM +11C LAST NIGHT TO -5C THIS
MORNING UNDER THAT UPPER TROUGH. AN ASSOCIATED SURFACE COLD FRONT
IS DRAPED FROM LAKE ONTARIO THROUGH CENTRAL WI INTO SOUTHERN MN.
THIS FRONT HAS BEEN MOVING SLOWLY BUT CONSISTENTLY SOUTHWARD TODAY
WITH A RIBBON OF STRATUS/STRATOCU BEHIND IT. ALSO SEEN UPSTREAM IS A
SHEARING OUT SHORTWAVE ACROSS NW MN WHICH WILL CONTINUE TO MOVE
SOUTHEASTWARD.
TONIGHT...GIVEN THE COLD FRONT ORIENTATION AND THE LOSS OF MIXING
OF WESTERLY WINDS...EXPECT THE SURFACE COLD FRONT TO PROGRESS
QUICKER DOWN THE LAKE THIS EVENING...REACHING CHICAGO BY JUST
AFTER SUNDOWN OR SO. THIS WILL MEAN A TURN TO NORTHEAST WINDS AND
A DROP IN TEMPERATURE BY SEVERAL DEGREES LIKELY IN JUST A COUPLE
HOURS. READINGS SHOULD THEN STABILIZE NEAR THE LAKE GIVEN THE
STILL MILD WATER TEMPERATURES. THE NAM AND RAP SOUNDINGS ALONG
WITH COLD AIR ADVECTION AND RH FIELDS SUPPORT AT LEAST PATCHY
STRATUS MAKING IT DOWN INTO THE AREA NOT LONG BEHIND THE FRONT.
LOW-LEVEL THERMAL PROFILES ALSO HOVER AROUND LAPSE RATES
SUPPORTIVE OF LAKE-INDUCED CLOUDS. WITH THESE FORECASTS MESHING
WITH OBSERVATIONAL TRENDS UPSTREAM...HAVE BUMPED UP SKY COVER
LATER THIS EVE INTO OVERNIGHT. ALSO...AFOREMENTIONED SHEARING
SHORT WAVE OVER NW MN WILL RIDE A TIGHT 600-800MB THERMAL GRADIENT
INTO NW/NC IL BY EARLY OVERNIGHT. NAM FORECAST SOUNDINGS OVER RFD
WOULD CONTINUE TO SUPPORT A CHANCE FOR SOME SPRINKLES LATE AS THE
WAVE OVERRIDES SOME OF THE LOWER LEVEL MOISTURE. SO CONTINUE THAT
IN THE FORECAST BUT HAVE JUST BACKED UP IN TIME. WHILE A COLD
FRONT IS EASING THROUGH...TEMPERATURES WILL END UP SEVERAL DEGREES
WARMER THAN LAST NIGHT WITH MORE OF A WIND COMPONENT AND
INCREASING CLOUD COVER ACTING AS INSULATION.
THURSDAY THROUGH SATURDAY...FAIRLY QUIET WEATHER INTO FRIDAY
CONTINUES TO BE THE TREND IN THE WEATHER PATTERN. NORTHEAST WINDS
WILL CONTINUE INTO THU WITH TEMPERATURES IN THE 70S ACROSS AREAS
NORTH OF I-80. WARM AIR ADVECTION BEGINS FRIDAY AS THE HIGHS
SHIFTS EAST. THE 04.00 EC WAS FAIRLY SHARP WITH THIS ALOFT AND
HAVING A COINCIDENT SHORT WAVE WITH OUTPUT QPF. ITS MORE CURRENT
RUN IS MORE IN LINE WITH OTHER GUIDANCE...THAT IS DRIER AND
CONTINUE AS SUCH IN THE FORECAST. NEXT SHORT WAVE DROPS OVER THE
GREAT LAKES WITH ASSOCIATED WEAK SURFACE COLD FRONT OOZING
SOUTHWARD ON SAT. BEST LAPSE RATES AND MOISTURE ARE REALLY
CONFINED TO THE FRONT...SO DO NOT INTRODUCE SHOWER CHANCES UNTIL
SAT AFTERNOON AND AT THAT LOW AT THIS TIME. TEMPS RIGHT NOW LOOK
TO BE IN THE MID 80S FOR SAT GIVEN LOCAL CLIMATOLOGY...AND GIVEN
LOW-LEVEL THERMAL VALUES WHAT THEY WERE TODAY BUT WITH EVEN MORE
SW ADVECTION.
MTF
EXTENDED FORECAST SAT NIGHT-WED...WEAK COLD FRONT CONTINUES TO DROP
SOUTH THROUGH THE AREA SATURDAY EVENING INTO SUNDAY. WILL KEEP LOW
POPS FOR SATURDAY NIGHT...AND FOR THE SOUTHERN PART OF THE FORECAST
AREA SUNDAY. HIGH PRESSURE MOVES ACROSS THE LAKES SUNDAY WITH
NORTHEAST SURFACE WINDS. THIS SHOULD BRING DRY AND A LITTLE COOLER
WEATHER...ESPECIALLY NEAR THE LAKE. SUNDAY NIGHT INTO MONDAY THE
UPPER RIDGE AXIS SHIFTS EAST TOWARD THE GREAT LAKES AND THE SURFACE
HIGH SHIFTS EAST BRINGING A RETURN TO SOUTHERLY FLOW AND WARMER
WEATHER. GUIDANCE PRODUCING SLIGHT CHANCE POPS MOST PERIODS DAYS 4
THOUGH 7 BUT DON`T SEE ANY REAL FOCUS FOR THUNDERSTORMS SUNDAY NIGHT
THROUGH MONDAY NIGHT OR TUESDAY. AS UPPER RIDGE AXIS PUSHES EAST
THROUGH THE GREAT LAKES THE HEAT DOMES SPREADS EAST. TUESDAY LOOKS
ESPECIALLY WARM WITH GFS 925 MB TEMPS 26-28C AND ECMWF EVEN A BIT
WARMER WITH STRONG WSW FLOW. LOOKING AT CIPS ANALOGS...SIMILAR
PATTERNS IN LATE AUGUST AND SEPTEMBER YIELDED SURFACE TEMPS MOSTLY
IN THE LOWER 90S. HAVE BUMPED UP MAX TEMPS OVER GUIDANCE FOR
TUESDAY. NOT GOING TO GO WILD WITH TEMPS 6 DAYS OUT...BUT WILL
CONTINUE TO MONITOR. COULD SEE NEAR RECORD HIGHS TUESDAY IF MODELS
PAN OUT AND WE GET ENOUGH SUNSHINE. UPPER TROF MOVES ACROSS THE
UPPER LAKES AND TRAILING SURFACE COLD FRONT APPROACHES THE FORECAST
AREA TUESDAY NIGHT INTO WEDNESDAY FOR THE BEST CHANCE OF
THUNDERSTORMS IN THE EXTENDED PERIOD.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* TIMING OF WINDS QUICKLY SHIFTING TO NORTHEAST FOLLOWING THE
FROPA THIS EVENING.
* SMALL CHANCE FOR A SHORT PERIOD OF MVFR CIGS FOLLOWING FROPA.
KREIN
//DISCUSSION...UPDATED 18Z...
THE MAIN FORECAST CONCERNS WILL BE THE TIMING OF THE COLD FRONTAL
PASSAGE THIS EVENING...AND THE ASSOCIATED RAPID WIND SHIFT OUT OF
THE NORTHEAST...AS WELL AS THE THREAT FOR A PERIOD OF MVFR CIGS
OVERNIGHT.
WINDS ARE EXPECTED TO REMAIN OUT OF THE WEST AROUND 10 KT THROUGH
THE AFTERNOON. HOWEVER...A COLD FRONT..CURRENTLY DROPPING SOUTHWARD
THROUGH CENTRAL WISCONSIN AND LAKE MICHIGAN...WILL PRODUCE A
SIGNIFICANT WIND SHIFT OUT OF THE NORTHEAST BY EARLY THIS EVENING AS
IT MOVES ACROSS THE TERMINALS. TIMING OF THIS FRONT APPEARS THAT IT
MAY BE A BIT SLOWER THAN PREVIOUSLY THOUGHT. THEREFORE...I PUSHED
OFF THE TIMING AROUND AN HOUR...WITH A PASSAGE AROUND OR SHORTLY
AFTER 02 UTC AT ORD...AND AFTER 03 UTC AT MDW. ONCE THIS FRONT
PASSES...EXPECT A RAPID WIND SHIFT OUT OF THE NORTHEAST. THESE WINDS
WILL LIKELY INCREASE SOME IN MAGNITUDE...WITH SOME GUSTS UP IN THE
UPPER TEENS...LATER TONIGHT INTO THURSDAY.
THE OTHER CONCERN IS FOR A PERIOD OF LOWER CLOUDS IN THE 1-2,000
FOOT RANGE LATER TONIGHT AFTER 04 UTC. CURRENT SATELLITE IMAGERY
INDICATES A GOOD AMOUNT OF MVFR CLOUD COVER IN THE WAKE OF THE COLD
FRONT ACROSS NORTHERN LAKE MICHIGAN AND NORTHERN WISCONSIN EARLY
THIS AFTERNOON. THIS CLOUD COVER MAY IMPACT NORTHERN ILLINOIS
OVERNIGHT TONIGHT BEFORE IMPROVING BY EARLY THURSDAY AS COLD AIR
MOVES IN ACROSS THE AREA. FOR THIS REASON...I HAVE OPTED TO ADD SOME
MVFR CIGS TO THE 18 UTC TAFS OVERNIGHT TONIGHT. CONFIDENCE IS LOW TO
MODERATE IN THIS OCCURRING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM CONFIDENCE OF TIMING OF FROPA THIS EVENING...WITH MEDIUM
TO HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM TO HIGH CONFIDENCE IN CEILING TRENDS...WITH LOW
CONFIDENCE IN THE POTENTIAL FOR A SHORT PERIOD OF MVFR CEILINGS
FOLLOWING THE FROPA.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SLIGHT CHANCE OF TSRA LATE...OTHERWISE VFR.
SUNDAY...SLIGHT CHANCE OF TSRA...OTHERWISE VFR.
MONDAY...SLIGHT CHANCE OF TSRA...OTHERWISE VFR.
TUESDAY...VFR.
RODRIGUEZ
&&
.MARINE...
229 PM CDT
A COLD FRONT IS STARTING TO MAKE ITS WAY DOWN LAKE MICHIGAN THIS
AFTERNOON WITH A PUSH OF NORTH-NORTHEASTERLY FLOW BEHIND THE FRONT
INCREASING THE WINDS INTO THE 15 TO 20 KT RANGE WITH OCCASIONAL
GUSTS TO 25 KT POSSIBLE. THE FRONT SHOULD CLEAR THE SOUTH END OF THE
LAKE AROUND MIDNIGHT TONIGHT. WITH A DECENT FETCH DOWN THE
LAKE...WAVES ARE EXPECTED TO BUILD INTO THE 3 TO 6 FT RANGE AT THE
SOUTH END OF THE LAKE PROMPTING A SMALL CRAFT ADVISORY FOR MAINLY
THE ILLINOIS NEARSHORE WATERS LATE THIS EVENING AND OVERNIGHT.
THESE CONDITIONS SHOULD SUBSIDE BACK BELOW CRITERIA THURSDAY
AFTERNOON AS HIGH PRESSURE PASSES OVER THE LAKE. AS THE HIGH
SHIFTS OVER THE EASTERN LAKES FRIDAY...SOUTHERLY FLOW INCREASES
AGAIN ACROSS THE LAKE. ANOTHER FRONT IS EXPECTED TO SAG SOUTH
ACROSS THE LAKE SATURDAY NIGHT INTO EARLY SUNDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM THURSDAY TO 5 AM
FRIDAY.
IN...BEACH HAZARDS STATEMENT...INZ001...4 AM THURSDAY TO 5 AM FRIDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...4 AM
THURSDAY TO 3 PM THURSDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
300 PM CDT WED SEP 4 2013
.DISCUSSION...
300 PM CDT
THE FORECAST CHALLENGES ARE MAINLY TEMPERATURES AS SUMMER LOOKS TO
WIN OUT OVER AUTUMN IN THE EARLY GOING OF SEPTEMBER.
SYNOPSIS...IMPRESSIVELY DEEP UPPER TROUGH OVER EASTERN CANADA IS
BEING REINFORCED THIS AFTERNOON WITH A VIGOROUS JET DIVING INTO
THE UPPER GREAT LAKES. AS A GEE-WHIZ AND A SIGN OF THE CHANGE IN
SEASONS...NOT HERE YET BUT UP NORTH...850MB TEMPS AT CWZC ON THE
SOUTHERN END OF JAMES BAY DROPPED FROM +11C LAST NIGHT TO -5C THIS
MORNING UNDER THAT UPPER TROUGH. AN ASSOCIATED SURFACE COLD FRONT
IS DRAPED FROM LAKE ONTARIO THROUGH CENTRAL WI INTO SOUTHERN MN.
THIS FRONT HAS BEEN MOVING SLOWLY BUT CONSISTENTLY SOUTHWARD TODAY
WITH A RIBBON OF STRATUS/STRATOCU BEHIND IT. ALSO SEEN UPSTREAM IS A
SHEARING OUT SHORTWAVE ACROSS NW MN WHICH WILL CONTINUE TO MOVE
SOUTHEASTWARD.
TONIGHT...GIVEN THE COLD FRONT ORIENTATION AND THE LOSS OF MIXING
OF WESTERLY WINDS...EXPECT THE SURFACE COLD FRONT TO PROGRESS
QUICKER DOWN THE LAKE THIS EVENING...REACHING CHICAGO BY JUST
AFTER SUNDOWN OR SO. THIS WILL MEAN A TURN TO NORTHEAST WINDS AND
A DROP IN TEMPERATURE BY SEVERAL DEGREES LIKELY IN JUST A COUPLE
HOURS. READINGS SHOULD THEN STABILIZE NEAR THE LAKE GIVEN THE
STILL MILD WATER TEMPERATURES. THE NAM AND RAP SOUNDINGS ALONG
WITH COLD AIR ADVECTION AND RH FIELDS SUPPORT AT LEAST PATCHY
STRATUS MAKING IT DOWN INTO THE AREA NOT LONG BEHIND THE FRONT.
LOW-LEVEL THERMAL PROFILES ALSO HOVER AROUND LAPSE RATES
SUPPORTIVE OF LAKE-INDUCED CLOUDS. WITH THESE FORECASTS MESHING
WITH OBSERVATIONAL TRENDS UPSTREAM...HAVE BUMPED UP SKY COVER
LATER THIS EVE INTO OVERNIGHT. ALSO...AFOREMENTIONED SHEARING
SHORT WAVE OVER NW MN WILL RIDE A TIGHT 600-800MB THERMAL GRADIENT
INTO NW/NC IL BY EARLY OVERNIGHT. NAM FORECAST SOUNDINGS OVER RFD
WOULD CONTINUE TO SUPPORT A CHANCE FOR SOME SPRINKLES LATE AS THE
WAVE OVERRIDES SOME OF THE LOWER LEVEL MOISTURE. SO CONTINUE THAT
IN THE FORECAST BUT HAVE JUST BACKED UP IN TIME. WHILE A COLD
FRONT IS EASING THROUGH...TEMPERATURES WILL END UP SEVERAL DEGREES
WARMER THAN LAST NIGHT WITH MORE OF A WIND COMPONENT AND
INCREASING CLOUD COVER ACTING AS INSULATION.
THURSDAY THROUGH SATURDAY...FAIRLY QUIET WEATHER INTO FRIDAY
CONTINUES TO BE THE TREND IN THE WEATHER PATTERN. NORTHEAST WINDS
WILL CONTINUE INTO THU WITH TEMPERATURES IN THE 70S ACROSS AREAS
NORTH OF I-80. WARM AIR ADVECTION BEGINS FRIDAY AS THE HIGHS
SHIFTS EAST. THE 04.00 EC WAS FAIRLY SHARP WITH THIS ALOFT AND
HAVING A COINCIDENT SHORT WAVE WITH OUTPUT QPF. ITS MORE CURRENT
RUN IS MORE IN LINE WITH OTHER GUIDANCE...THAT IS DRIER AND
CONTINUE AS SUCH IN THE FORECAST. NEXT SHORT WAVE DROPS OVER THE
GREAT LAKES WITH ASSOCIATED WEAK SURFACE COLD FRONT OOZING
SOUTHWARD ON SAT. BEST LAPSE RATES AND MOISTURE ARE REALLY
CONFINED TO THE FRONT...SO DO NOT INTRODUCE SHOWER CHANCES UNTIL
SAT AFTERNOON AND AT THAT LOW AT THIS TIME. TEMPS RIGHT NOW LOOK
TO BE IN THE MID 80S FOR SAT GIVEN LOCAL CLIMATOLOGY...AND GIVEN
LOW-LEVEL THERMAL VALUES WHAT THEY WERE TODAY BUT WITH EVEN MORE
SW ADVECTION.
MTF
EXTENDED FORECAST SAT NIGHT-WED...WEAK COLD FRONT CONTINUES TO DROP
SOUTH THROUGH THE AREA SATURDAY EVENING INTO SUNDAY. WILL KEEP LOW
POPS FOR SATURDAY NIGHT...AND FOR THE SOUTHERN PART OF THE FORECAST
AREA SUNDAY. HIGH PRESSURE MOVES ACROSS THE LAKES SUNDAY WITH
NORTHEAST SURFACE WINDS. THIS SHOULD BRING DRY AND A LITTLE COOLER
WEATHER...ESPECIALLY NEAR THE LAKE. SUNDAY NIGHT INTO MONDAY THE
UPPER RIDGE AXIS SHIFTS EAST TOWARD THE GREAT LAKES AND THE SURFACE
HIGH SHIFTS EAST BRINGING A RETURN TO SOUTHERLY FLOW AND WARMER
WEATHER. GUIDANCE PRODUCING SLIGHT CHANCE POPS MOST PERIODS DAYS 4
THOUGH 7 BUT DON`T SEE ANY REAL FOCUS FOR THUNDERSTORMS SUNDAY NIGHT
THROUGH MONDAY NIGHT OR TUESDAY. AS UPPER RIDGE AXIS PUSHES EAST
THROUGH THE GREAT LAKES THE HEAT DOMES SPREADS EAST. TUESDAY LOOKS
ESPECIALLY WARM WITH GFS 925 MB TEMPS 26-28C AND ECMWF EVEN A BIT
WARMER WITH STRONG WSW FLOW. LOOKING AT CIPS ANALOGS...SIMILAR
PATTERNS IN LATE AUGUST AND SEPTEMBER YIELDED SURFACE TEMPS MOSTLY
IN THE LOWER 90S. HAVE BUMPED UP MAX TEMPS OVER GUIDANCE FOR
TUESDAY. NOT GOING TO GO WILD WITH TEMPS 6 DAYS OUT...BUT WILL
CONTINUE TO MONITOR. COULD SEE NEAR RECORD HIGHS TUESDAY IF MODELS
PAN OUT AND WE GET ENOUGH SUNSHINE. UPPER TROF MOVES ACROSS THE
UPPER LAKES AND TRAILING SURFACE COLD FRONT APPROACHES THE FORECAST
AREA TUESDAY NIGHT INTO WEDNESDAY FOR THE BEST CHANCE OF
THUNDERSTORMS IN THE EXTENDED PERIOD.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WINDS RAPIDLY TURNING NORTHEAST WITH FROPA THIS EVENING.
* MVFR CEILINGS POSSIBLY DEVELOPING ACROSS THE TERMINALS AFTER 04
UTC TONIGHT.
KJB
//DISCUSSION...UPDATED 18Z...
THE MAIN FORECAST CONCERNS WILL BE THE TIMING OF THE COLD FRONTAL
PASSAGE THIS EVENING...AND THE ASSOCIATED RAPID WIND SHIFT OUT OF
THE NORTHEAST...AS WELL AS THE THREAT FOR A PERIOD OF MVFR CIGS
OVERNIGHT.
WINDS ARE EXPECTED TO REMAIN OUT OF THE WEST AROUND 10 KT THROUGH
THE AFTERNOON. HOWEVER...A COLD FRONT..CURRENTLY DROPPING SOUTHWARD
THROUGH CENTRAL WISCONSIN AND LAKE MICHIGAN...WILL PRODUCE A
SIGNIFICANT WIND SHIFT OUT OF THE NORTHEAST BY EARLY THIS EVENING AS
IT MOVES ACROSS THE TERMINALS. TIMING OF THIS FRONT APPEARS THAT IT
MAY BE A BIT SLOWER THAN PREVIOUSLY THOUGHT. THEREFORE...I PUSHED
OFF THE TIMING AROUND AN HOUR...WITH A PASSAGE AROUND OR SHORTLY
AFTER 02 UTC AT ORD...AND AFTER 03 UTC AT MDW. ONCE THIS FRONT
PASSES...EXPECT A RAPID WIND SHIFT OUT OF THE NORTHEAST. THESE WINDS
WILL LIKELY INCREASE SOME IN MAGNITUDE...WITH SOME GUSTS UP IN THE
UPPER TEENS...LATER TONIGHT INTO THURSDAY.
THE OTHER CONCERN IS FOR A PERIOD OF LOWER CLOUDS IN THE 1-2,000
FOOT RANGE LATER TONIGHT AFTER 04 UTC. CURRENT SATELLITE IMAGERY
INDICATES A GOOD AMOUNT OF MVFR CLOUD COVER IN THE WAKE OF THE COLD
FRONT ACROSS NORTHERN LAKE MICHIGAN AND NORTHERN WISCONSIN EARLY
THIS AFTERNOON. THIS CLOUD COVER MAY IMPACT NORTHERN ILLINOIS
OVERNIGHT TONIGHT BEFORE IMPROVING BY EARLY THURSDAY AS COLD AIR
MOVES IN ACROSS THE AREA. FOR THIS REASON...I HAVE OPTED TO ADD SOME
MVFR CIGS TO THE 18 UTC TAFS OVERNIGHT TONIGHT. CONFIDENCE IS LOW TO
MODERATE IN THIS OCCURRING.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION TODAY...WITH MEDIUM
CONFIDENCE OF TIMING AND TRENDS OF FROPA THIS EVENING.
* MEDIUM CONFIDENCE WITH CEILING TRENDS LATER TONIGHT...WITH LOW-
MEDIUM CONFIDENCE IN THE POTENTIAL FOR FOR A PERIOD OF MVFR
CEILINGS AFTER 04 UTC.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...VFR.
SATURDAY...SLIGHT CHANCE OF TSRA LATE...OTHERWISE VFR.
SUNDAY...SLIGHT CHANCE OF TSRA...OTHERWISE VFR.
MONDAY...SLIGHT CHANCE OF TSRA...OTHERWISE VFR.
TUESDAY...VFR.
RODRIGUEZ
&&
.MARINE...
229 PM CDT
A COLD FRONT IS STARTING TO MAKE ITS WAY DOWN LAKE MICHIGAN THIS
AFTERNOON WITH A PUSH OF NORTH-NORTHEASTERLY FLOW BEHIND THE FRONT
INCREASING THE WINDS INTO THE 15 TO 20 KT RANGE WITH OCCASIONAL
GUSTS TO 25 KT POSSIBLE. THE FRONT SHOULD CLEAR THE SOUTH END OF THE
LAKE AROUND MIDNIGHT TONIGHT. WITH A DECENT FETCH DOWN THE
LAKE...WAVES ARE EXPECTED TO BUILD INTO THE 3 TO 6 FT RANGE AT THE
SOUTH END OF THE LAKE PROMPTING A SMALL CRAFT ADVISORY FOR MAINLY
THE ILLINOIS NEARSHORE WATERS LATE THIS EVENING AND OVERNIGHT.
THESE CONDITIONS SHOULD SUBSIDE BACK BELOW CRITERIA THURSDAY
AFTERNOON AS HIGH PRESSURE PASSES OVER THE LAKE. AS THE HIGH
SHIFTS OVER THE EASTERN LAKES FRIDAY...SOUTHERLY FLOW INCREASES
AGAIN ACROSS THE LAKE. ANOTHER FRONT IS EXPECTED TO SAG SOUTH
ACROSS THE LAKE SATURDAY NIGHT INTO EARLY SUNDAY.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 PM EDT WED SEP 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 407 PM EDT WED SEP 4 2013
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL THROUGH THE
UPPER GREAT LAKES BETWEEN A LOW OVER NRN QUEBEC AND A RIDGE FROM
COLORADO THROUGH THE WRN PLAINS. WITH CONFLUENT FLOW AND 700-300 MB
QVECTOR DIV BUILDING INTO THE AREA...EXPECT MAINLY CLEAR SKIES TO
PREVAIL WITH ONLY SOME BANDS OF CIRRUS THROUGH THE ERN CWA...PER VIS
IMAGERY. AT THE SFC...HIGH PRES FROM SRN MANITOBA INTO NW ONTARIO
WAS BUILDING INTO THE NRN GREAT LAKES WITH INFLUX OF DRY AIR ON NRN
ACYC FLOW. LOWER DEWPOINTS UPSTREAM FROM LAKE SUPERIOR (READINGS IN
THE UPPER 30S) WERE FILTERING TOWARD UPPER MI.
TONIGHT...EVEN WITH PWAT VALUES AROUND 0.50 INCH CLIMBING TO NEAR
0.75 INCH...WITH HIGH PRES BUILDING INTO UPPER MI...MOSTLY CLEAR
SKIES AND LIGHT WINDS ALLOW TEMPS TO DROP OFF TOWARD THE LOWER END
OF GUIDANCE. READINGS INTO THE UPPER 30S INLAND WEST AND LOW TO MID
40S OVER THE EAST AND ALONG THE GREAT LAKES ARE EXPECTED. PATCHY
FROST MAY BE POSSIBLE IN THE TYPICAL COLD SPOTS FROM REPUBLIC AND
CHAMPION TO AMASA...IRON RIVER AND WATERSMEET.
THURSDAY...UNDER ABUNDANT SUNSHINE WITH 850 MB TEMPS IN THE 6C TO
10C RANGE...TEMPS WILL REBOUND CLOSER TO SEASONAL AVERAGES WITH HIGHS
RANGING FROM THE UPPER 60S EAST TO THE LOWER 70S WEST.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 407 PM EDT WED SEP 4 2013
HIGH PRESSURE WILL KEEP WEATHER QUIET THURSDAY NIGHT THROUGH EARLY
FRIDAY AFTERNOON. AS THE HIGH CENTERS OVER THE EASTERN
SEABOARD...UPPER MICHIGAN IS POSITIONED ON THE NORTHWESTERN
PERIPHERY OF THE RIDGE...MAKING US VULNERABLE FOR WEAK WAVES TO
SLIDE THROUGH. THE FIRST OF THESE SLIDES OUT AHEAD OF THE MAIN
TROUGH ON FRIDAY AFTERNOON. MODELS ARE MOSTLY IN AGREEMENT...WITH
THE EXCEPTION OF THE GFS WHICH BRINGS THE MAIN TROUGH IN MUCH
QUICKER...SO STRAYED FROM THAT SOLUTION. USED PRIMARILY THE
GEM/ECMWF FOR THIS LONG TERM FORECAST.
WEAK MOISTURE ADVECTION/CONVERGENCE SHOWS UP FOR THE MID LEVELS AND
FOCUSES ACROSS THE WEST AND NORTHERN PORTIONS OF THE CWA EARLIER IN
THE DAY...PRIMARILY OVER THE KEWEENAW AND LAKE SUPERIOR. THROUGHOUT
THE DAY THIS REGION MOVES EAST-SOUTHEASTWARD TOWARDS QUEBEC...SO
KEPT PCP CHANCES FAR EAST INTO FRIDAY EVENING. OVERALL...850-500MB
QVECTOR CONVERGENCE IS PALTRY BUT WARRANTS SOME SLIGHT CHANCE/CHANCE
POPS. LOW LEVELS ARE FAIRLY DRY THOUGH...AND INSTABILITY IS MINIMAL.
WILL KEEP THE POPS PRIMARILY OVER THE LAKE AND FAR EAST FOR NOW.
FRIDAY NIGHT THROUGH SATURDAY THE STRONGER TROUGH MOVES THROUGH THE
GREAT LAKES AS LOW PRESSURE OVER JAMES BAY ON FRIDAY MOVES INTO
QUEBEC. MOISTURE IS DEEPER AND INSTABILITY IS GREATER THIS GO
AROUND...WHICH WILL SUPPORT SHOWERS AND TSTORMS ACROSS THE CWA. THE
WESTERN CWA IS LIKELY TO SEE SHOWERS/A FEW TSTORMS STARTING LATER
FRIDAY NIGHT AND CONTINUING THROUGH MAINLY SATURDAY MORNING. WITH
GREATER INSTABILITY BUILDING TOWARDS SATURDAY AFTERNOON ALONG THE WI
BORDER AND CENTRAL U.P. LINGERED CHANCE POPS THERE THROUGH THE
AFTERNOON.
THE BEST MOISTURE IS CENTRAL AND EAST HOWEVER...AND SFC BASED CAPE
IS AROUND 1000-500 J/KG FOR THE AFTERNOON. WITH THE FRONT PASSING
THROUGH THE CENTRAL CWA AROUND 18Z AND NORTHWEST FLOW ALOFT...EXPECT
WE WILL SEE SOME ACTIVITY. 0-6KM BULK SHEAR IS AROUND 20-30
KNOTS...SO DO NOT EXPECT ANYTHING TOO GET TOO ORGANIZED. ANY SEVERE
THREAT AS OF RIGHT NOW LOOKS TO BE VERY ISOLATED.
ON SUNDAY HIGH PRESSURE BRINGS A BRIEF BREAK TO THE PRECIPITATION.
MONDAY AND TUESDAY A WARM FRONT LIFTS ACROSS THE MIDWEST WITH A
STRONGER LOW PRESSURE SYSTEM IN THE NORTHERN PLAINS. THIS LOW WILL
MOVE NORTHEASTWARD INTO ONTARIO...AND EVENTUALLY BRING A COLD FRONT
ACROSS UPPER MI ON WEDNESDAY. HAVE CHANCE POPS IN THE FORECAST FOR
NOW...GIVEN DIFFERENCES BETWEEN MODELS IN THE LOCATION OF THE LOW
PRESSURE SYSTEM DURING THESE TIMES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 139 PM EDT WED SEP 4 2013
ANY LEFTOVER MVFR CIGS AT IWD ARE EXPECTED TO DEPART EARLY THIS
AFTERNOON AS DRIER AIR MOVES IN. OTHERWISE...WITH HIGH PRESSURE
BUILDING INTO THE REGION...EXPECT VFR CONDITIONS AND LIGHT WINDS
THROUGH THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT WED SEP 4 2013
WITH HIGH PRES BUILDING INTO THE UPPER LAKES...WINDS WILL DIMINISH
TO LESS THAN 20 KTS LATER TONIGHT INTO THURSDAY. SW WINDS WILL
INCREASE ON FRIDAY IN THE TIGHTER PRESSURE GRADIENT BETWEEN THE
EXITING HIGH PRESSURE AND A COLD FRONT THAT ARRIVES THIS WEEKEND.
EXPECT WINDS ON FRIDAY TO STAY LESS THAN 25 KTS. WINDS FOR THE
REMAINDER OF THE FORECAST PERIOD WILL REMAIN LESS THAN 20 KNOTS DUE
TO WEAKER PRESSURE GRADIENT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ005-
006.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...MCD
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS ELKO NV
1046 AM PDT WED SEP 4 2013
.SYNOPSIS...YET ANOTHER ROUND OF THUNDERSTORMS ON TAP ACROSS
NEVADA TODAY AND TONIGHT. MANY STORMS WILL AGAIN PRODUCE VERY
HEAVY RAINFALL...AND A FLASH FLOOD WATCH IS NOW IN EFFECT THROUGH
EARLY THURSDAY MORNING. DRIER AIR AND STRONGER WINDS WILL PUSH
INTO NORTHWESTERN NEVADA ON THURSDAY. THUNDERSTORM CHANCES WILL
SLOWLY DECREASE ACROSS EASTERN NEVADA THROUGH SATURDAY.
&&
.FIRE WEATHER UPDATE...ISSUED A RED FLAG WARNING FOR GUSTY WINDS
AND LOW RELATIVE HUMIDITY FOR ZONE 467 IN NORTHWEST NEVADA...WHICH
WILL BE IN EFFECT ON THURSDAY BETWEEN 1 PM AND 9 PM PDT. NO OTHER
CHANGES AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED AT 810 AM /
SYNOPSIS...YET ANOTHER ROUND OF THUNDERSTORMS ON TAP ACROSS
NEVADA TODAY AND TONIGHT. MANY STORMS WILL AGAIN PRODUCE VERY
HEAVY RAINFALL...AND A FLASH FLOOD WATCH IS NOW IN EFFECT THROUGH
EARLY THURSDAY MORNING. THUNDERSTORM CHANCES WILL SLOWLY DECREASE
ACROSS EASTERN NEVADA THROUGH SATURDAY.
UPDATE...SENT OUT AN UPDATED FORECAST TO INCREASE THUNDERSTORM
COVERAGE THIS AFTERNOON AND THIS EVENING, TO THE LIKELY/NUMEROUS
CATEGORY IN MANY CASES. 12Z NAM AND THE 3-KM HRRR ARE FORECASTING
ANOTHER BUSY AFTERNOON AND EVENING, WITH STORMS REDEVELOPING AGAIN
AROUND NOON. THIS MORNING`S ELKO SOUNDING IS STILL VERY MOIST WITH
PRECIPITABLE WATER NEAR 1 INCH, WITH A CONVECTIVE TEMPERATURE OF
ONLY 80 DEGREES. STORM MOTION AGAIN TODAY WILL BE TO THE NORTHEAST
AT 10-20 MPH, BUT SO FAR THAT HAS DONE LITTLE TO HINDER THE FLASH
FLOODING THREAT THE PAST FEW DAYS. CONVECTION WILL CONTINUE PAST
5 PM, WITH SOME STORMS LASTING ALL NIGHT AGAIN, SO EXTENDED THE
FLASH FLOOD WATCH THROUGH 5 AM THURSDAY MORNING. SHEAR DOES
INCREASE SOME ACROSS MAINLY NORTHERN NEVADA, IN ASSOCIATION WITH
CLOSED LOW WEST OF OREGON, SO ALSO EXPECTING A FEW SEVERE STORMS
THIS AFTERNOON, ESPECIALLY NEAR THE OREGON/IDAHO BORDERS. TURNER
PREV DISCUSSION... /ISSUED AT 316 AM /
SYNOPSIS...AS A LOW PRESSURE SYSTEM SLOWLY APPROACHES FROM OFF
THE PACIFIC COAST...ENOUGH MOISTURE WILL BE AVAILABLE TO TRIGGER
THUNDERSTORMS ALL ACROSS THE SILVER STATE AGAIN TODAY. UNSETTLED
WEATHER WILL CONTINUE ACROSS EASTERN NEVADA THROUGH SATURDAY.
SHORT TERM...TODAY THROUGH THURSDAY. A COUPLE VERY STRONG
THUNDERSTORM CELLS LINGERED PAST MIDNIGHT...IN WHITE PINE COUNTY
AND NORTHERN ELKO COUNTY. STILL A LIGHTNING STRIKE OR TWO
OCCURRING AT 3 AM PDT...EVEN IN HUMBOLDT COUNTY AS A COUPLE
UNDETECTABLE SHORTWAVES CUT THROUGH THE WEST. THE GFS MODEL SHOWS
THE TAIL END OF A COUPLE 250 MB JET STREAKS MERGING OVER CENTRAL
NEVADA BY 12Z THIS MORNING AND INSTABILITY SHOULD THEREAFTER SHUT
DOWN UNTIL HEATING INSTIGATES MORE CONVECTION LATER THIS MORNING.
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE SYNOPTIC PATTERN. A
PACIFIC LOW PRESSURE SYSTEM WILL SLOWLY MOVE ONSHORE OVER OREGON
BY THURSDAY. HIGH PRESSURE WILL HOLD POSITION OVER COLORADO AND
KANSAS HOWEVER THE INCOMING UPPER LOW WILL EFFECTIVELY SHUNT THE
MOIST FLOW ORIGINATING NEAR THE BAJA REGION.
THERE IS SOME MODEL DISCREPANCY ON PRECIPITABLE WATER AMOUNTS
TODAY HOWEVER THERE SHOULD BE PLENTY RESIDUAL MOISTURE AVAILABLE TO
ALLOW DEVELOPMENT OF SOME MORE HEAVY RAIN PRODUCING THUNDERSTORMS.
THE FLASH FLOOD WATCH HAS BEEN EXTENDED THROUGH THIS AFTERNOON
FOR PARTS OF NORTHERN AND CENTRAL NEVADA. THE DRY UPPER LOW WILL
SHOVE THE MOIST FLOW EAST BY THURSDAY. THE PRESSURE GRADIENT WILL
TIGHTEN AND BREEZY WINDS ARE EXPECTED FOR THURSDAY AFTERNOON.
LONG TERM...THURSDAY NIGHT THROUGH NEXT TUESDAY. THE FORECAST
PERIOD COMMENCES WITH A CLOSED UPPER LOW AND A POSITIVE TILT TROF
MOVING INTO THE WEST...DISPLACING THE RIDGE INTO THE CENTRAL
PLAINS. THE NCEP AND NON-NCEP MODELS ARE IN DESCENT AGREEMENT
THROUGH THE PERIOD. AS TIME ELAPSES...THE UPPER TROF WILL NUDGE
THE RIDGE EASTWARD...AND THIS PROGRESSION WILL EFFECTIVELY CUT OF
THE MONSOONAL FLOW...USHERING...A DRY AIRMASS INTO THE SILVER
STATE. ALTHOUGH...WITH PWS HOVERING AROUND .75 OF AN INCH ALONG
THE UTAH/NV BORDER...KEPT SLIGHT CHANCE POPS OVER ELKO AND WHITE
PINE COUNTIES. BY THE WEEKEND...THE MODELS START TO BECOME
SLIGHTLY OUT OF PHASE...BUT GENERALLY DEPICT WIDESPREAD NORTHWEST
DRY FLOW OVER THE CWA ON SUNDAY...MONDAY...AND TUESDAY. SENSIBLE
WEATHER-WISE EXPECT SLIGHTLY COOLER TEMPERATURES AND MOSTLY CLEAR
SKIES.
AVIATION...VFR CONDITIONS ARE EXPECTED AT KWMC KEKO...KELY AND KTPH.
HOWEVER...MONSOON MOISTURE WILL CONTINUE TO PRODUCE SHOWERS AND
THUNDERSTORMS AGAIN TODAY...WILL KEEP VC TS IN TAFS. IF THE STORMS
MOVE NEAR THE TERMINAL EXPECT...FLOODING RAINS...GUSTY WINDS...TURBULENCE
AND SMALL HAIL. THE TURBULENCE GUIDANCE FROM THE AVIATION WEATHER
CENTER SUGGESTS THAT ANY NON-CONVECTIVE TURBULENCE OVER THE REGION
WOULD BE LIGHT. OFTEN MONSOON AIR MASSES ARE SLOW TO CLEAR
OUT...EXPECTING TS OVER EASTERN NV ON THURSDAY...POTENTIALLY
IMPACTING KEKO AND KELY.
FIRE WEATHER...SHOWERS AND THUNDERSTORMS WITH WETTING RAINS WILL
DEVELOP AGAIN TODAY AND FLASH FLOODING OR DEBRIS FLOWS WILL BE A
POSSIBILITY IN SOME AREAS. A DRYING TREND IS EXPECTED BEGINNING
THURSDAY WITH THUNDERSTORMS MAINLY AFFECTING EASTERN NEVADA
THROUGH SATURDAY. BREEZY WINDS WILL DEVELOP ON THURSDAY AND
FRIDAY WITH GUSTS NEAR 30 MPH...HOWEVER HUMIDITY LEVELS ARE EXPECTED
TO BE ABOVE 15 PERCENT WHERE WINDS WILL BE STRONGEST.
&&
.LKN WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NORTHERN ELKO
COUNTY...NORTHERN LANDER COUNTY AND NORTHERN EUREKA COUNTY...
RUBY MOUNTAINS/EAST HUMBOLDT RANGE...SOUTH CENTRAL ELKO COUNTY...
SOUTHEASTERN ELKO COUNTY...SOUTHERN LANDER COUNTY AND SOUTHERN
EUREKA COUNTY...SOUTHWESTERN ELKO COUNTY...WHITE PINE COUNTY.
RED FLAG WARNING FROM 1 PM TO 9 PM PDT THURSDAY FOR HUMBOLDT
COUNTY.
&&
$$
96
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
100 PM EDT WED SEP 4 2013
.SYNOPSIS...
DRIER AIR WILL BUILD OVER THE AREA TODAY IN WAKE OF A WEAK COLD
FRONT. CANADIAN HIGH PRESSURE WILL BRING A REINFORCEMENT OF DRY
AND SLIGHTLY COOLER AIR FRIDAY INTO SATURDAY. A WARMING TREND IN
EXPECTED EARLY NEXT WEEK AS AN UPPER RIDGE BUILDS OVER THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...DRIER AIR IN WAKE OF A COLD FRONT HAS
ERADICATED THE WRETCHED QUALITY OF THE MUGGY AIR MASS WHICH HAS
RECENTLY BLANKETED THE AREA. DEWPOINTS WERE DROPPING IN THE 60S
AS DRIER AIR AND MIXING WERE GETTING UNDERWAY THIS MORNING. THE
FRONT ITSELF WAS LOSING IDENTITY OFFSHORE NEARING THE GULF-STREAM
AND WAS CURLED BACK TOWARD THE SW SOUTH OF WINYAH BAY AND YAWKEY
SOUTH ISLAND RESERVE. HIGH RESOLUTION NEAR TERM MODELS WRF NSSL
AND THE HRRR DEPICT SIMILAR SOLUTIONS...ISOLATED SHOWERS FAVORED
OVER OUR SOUTHERN COASTAL INTERIOR ZONES WHERE HIGH MOISTURE
CONTENT PREVAILS. AFTERNOON SEA BREEZE CONVERGENCE WILL ALLOW A
FEW MODERATE CUMULUS BUILD UPS. UPPER LEVEL MOISTURE REMAINS
SPARSE SO ONLY SHOWERS ARE ADVERTISED VERSUS TSTMS. THE BEST
CHANCE OF A SHOWER WILL BE BETWEEN 2PM-6PM. DIURNAL COOLING
SHOULD QUICKLY DIMINISH CONVECTION INTO EARLY EVENING. LOWS
TONIGHT UNDER CLEAR SKIES MAINLY MIDDLE AND UPPER 60S WITH
LOWER 70S ALONG THE COAST IN A LIGHT SOUTHERLY WIND FLOW.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...COLD FRONT STALLED NOT TO FAR OFFSHORE BUT A
SECONDARY AXIS OF WEAK CONVERGENCE DEVELOPS ALONG THE COASTAL PLAIN
IN ASSOCIATION WITH A SURFACE TROUGH. FORECAST SOUNDINGS SHOW VERY
DRY MID LEVELS AND SO MEASURABLE PRECIPITATION SEEMS QUITE UNLIKELY
BUT A SLIGHT CHANCE WILL BE CARRIED ALONG COASTAL ZONES IN THE EVENT
OF A STRAY 0.01". WHAT LITTLE CAA BEHIND THE BOUNDARY THERE HAD
BEEN ON WED WILL BE GONE BY THURS AND TEMPS TO BE BACK A FEW DEGREES
ABOVE CLIMO. MORE APPRECIABLE FRONT TO COME THROUGH EITHER THURSDAY
NIGHT OR FRIDAY MORNING DEPENDING ON MODEL CHOICE. GIVEN THE STRONG
SURFACE PRESSURE ADVECTION PUSHING IT PREFER THE QUICKER TIMING I.E.
WRF. FRIDAY HIGHS KNOCKED BACK DOWN A FEW DEGREES BELOW CLIMO AND
DEWPOINTS TO FALL INTO THE MID OR EVEN LOW 60S...THE LATTER MOST
LIKELY OVER NW ZONES. FAR SRN SC ZONES MAY HOLD ON TO DEWPOINTS IN
THE UPPER 60S. INTERESTING SKY COVER FORECAST LATE FRIDAY INTO
FRIDAY NIGHT AS GUIDANCE SHOWING SOME ATLANTIC MOISTURE ASSOC WITH
THE NE SURGE. MID LEVELS REMAIN VERY DRY...PROBABLY DRIER THAN FCST
SOUNDINGS SHOW IN THE CONTINUED NW FLOW...AND WITH NO NOTICEABLE
FRONTAL INVERSION THIS MOISTURE MAY NOT GET TRAPPED AS MUCH AS THE
RELATIVELY CLOUDY GUIDANCE IMPLIES.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 AM WEDNESDAY...VERY QUIET WEATHER ON TAP FOR THE PERIOD.
UPPER RIDGE REMAINS ACROSS THE PLAINS THROUGH SUNDAY OR MONDAY WHILE
SURFACE HIGH CONTINUES TO BUILD IN FROM THE NORTH. MONDAY INTO
TUESDAY WILL BRING THE UPPER RIDGE EASTWARD IN A WEAKENING STATE.
THE SURFACE HIGH WILL SHIFT SLIGHTLY EASTWARD AS WELL BUT NOT ENOUGH
FOR SUFFICIENT MOISTURE FLUX LOCALLY. TEMPERATURES NEAR CLIMO EARLY
IN THE PERIOD WITH JUST A VERY SLOW RISE THROUGHOUT AS A RESULT OF
SOLAR MODERATION AS OPPOSED TO ANY THERMAL ADVECTION.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...MODELS STILL ADVERTISING ISOLATED LIGHT SHOWERS MAINLY
ALONG THE RESULTANT SEA BREEZE BOUNDARY THIS AFTERNOON. BEST
CHANCE WILL BE OVER THE SOUTHERN THIRD OF THE CWA WHERE THE BEST
PWATS RESIDE. WINDS WILL BE EASTERLY FOR THE MOST PART THIS
AFTERNOON...STRONGEST NEAR THE COAST. TONIGHT...GOOD RADIATIONAL
COOLING CONDITIONS WILL BRING IN THE CHANCE FOR FOG AFTER 08Z.
INLAND TERMINALS STAND THE BEST CHANCE FOR POTENTIAL IFR
CONDITIONS. THURSDAY...NICE AVIATION DAY WITH FOG BURNING OFF
EARLY WITH SCATTERED TO NEARLY CLEAR SKIES AND LIGHT WINDS.
EXTENDED OUTLOOK...MORNING FOG/STRATUS IS POSSIBLE THROUGH THE
EXTENDED PERIOD. SLIGHT CHANCE OF SHOWERS FRIDAY AND MONDAY WITH
WEAK BACKDOOR COLD FRONTS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...WEAK COLD FRONT HAS MOVED SOUTH AND EAST
OF THE OF THE WATERS THIS MORNING AND WILL BE FOLLOWED BY WEAK
OFFSHORE FLOW. DIFFUSE GRADIENT BEHIND THE FRONT WILL ALLOW
DEVELOPMENT OF AFTERNOON SEA BREEZE. THIS WILL LEAD TO STRONGEST
WINDS OVER THE NEAR SHORE WATERS WITH LIGHTER WINDS AWAY FROM
SHORE. SPEEDS WILL STRUGGLE TO EXCEED 10 KT BUT ISOLATED GUSTS IN
THE AFTERNOON TO 15 KT WILL BE POSSIBLE. DISSIPATION OF SEA BREEZE
CIRCULATION THIS EVENING WILL RESULT IN WINDS BECOMING LIGHT AND
VARIABLE OVERNIGHT. SEAS WILL RUN 2 TO 3 FT THROUGH THE PERIOD.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...EVEN THOUGH A FRONT WILL BE STALLED AND
WEAKENING NOT FAR TO THE SOUTH ON THURSDAY THE FLOW WILL TURN BACK
AROUND TO A SOUTHERLY DIRECTION AS SURFACE TROUGHINESS DEVELOPS JUST
INLAND FROM THE COAST. IT WILL BE A VERY LIGHT FLOW WITH SPEEDS
GENERALLY CAPPED AT 10KT RESULTING IN 2 FT SEAS. A FAIRLY QUICK VEER
TO THE NORTH IS SLATED FOR THURSDAY NIGHT ALTHOUGH SOME LESS FAVORED
MODEL SOLUTIONS ARE SLOWER. A RELATIVELY STRONG HIGH WILL BUILD IN
BEHIND THE THURSDAY NIGHT FRONT AND WIND SPEEDS MAY INCREASE A
CATEGORY OR MORE BUILDING SEAS INTO THE 2 TO 4 FT RANGE...A LITTLE
LOWER OVER SRN ZONES.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...ANY RESIDUAL VESTIGE OF THE SURGE FROM THE
SHORT TERM SHOULD QUICKLY ABATE AS SATURDAY WEARS ON AS HIGH
PRESSURE BECOMES CENTERED OFF OF NEW ENGLAND/MID ATLANTIC AND
EXTENDS RIDGE AXIS INTO THE CAROLINAS. WINDS WILL BE ONSHORE EITHER
E OR NE AND FALL TO 10 KTS ALLOWING SEAS TO SETTLE TO 2 FT. A PIECE
OF THE HIGH BREAKS OFF AND STAYS BEHIND ACROSS THE CAROLINAS ON
SUNDAY CONTINUING THE TREND OF VERY LIGHT ONSHORE WIND AND SEAS
CAPPED AT 2 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MJC
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL/8
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1231 PM EDT WED SEP 4 2013
.SYNOPSIS...
DRIER AIR WILL BUILD OVER THE AREA TODAY IN WAKE OF A WEAK COLD
FRONT. CANADIAN HIGH PRESSURE WILL BRING A REINFORCEMENT OF DRY
AND SLIGHTLY COOLER AIR FRIDAY INTO SATURDAY. A WARMING TREND IN
EXPECTED EARLY NEXT WEEK AS AN UPPER RIDGE BUILDS OVER THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...DRIER AIR IN WAKE OF A COLD FRONT HAS
ERADICATED THE WRETCHED QUALITY OF THE MUGGY AIR MASS WHICH HAS
RECENTLY BLANKETED THE AREA. DEWPOINTS WERE DROPPING IN THE 60S
AS DRIER AIR AND MIXING WERE GETTING UNDERWAY THIS MORNING. THE
FRONT ITSELF WAS LOSING IDENTITY OFFSHORE NEARING THE GULF-STREAM
AND WAS CURLED BACK TOWARD THE SW SOUTH OF WINYAH BAY AND YAWKEY
SOUTH ISLAND RESERVE. HIGH RESOLUTION NEAR TERM MODELS WRF NSSL
AND THE HRRR DEPICT SIMILAR SOLUTIONS...ISOLATED SHOWERS FAVORED
OVER OUR SOUTHERN COASTAL INTERIOR ZONES WHERE HIGH MOISTURE
CONTENT PREVAILS. AFTERNOON SEA BREEZE CONVERGENCE WILL ALLOW A
FEW MODERATE CUMULUS BUILD UPS. UPPER LEVEL MOISTURE REMAINS
SPARSE SO ONLY SHOWERS ARE ADVERTISED VERSUS TSTMS. THE BEST
CHANCE OF A SHOWER WILL BE BETWEEN 2PM-6PM. DIURNAL COOLING
SHOULD QUICKLY DIMINISH CONVECTION INTO EARLY EVENING. LOWS
TONIGHT UNDER CLEAR SKIES MAINLY MIDDLE AND UPPER 60S WITH
LOWER 70S ALONG THE COAST IN A LIGHT SOUTHERLY WIND FLOW.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...COLD FRONT STALLED NOT TO FAR OFFSHORE BUT A
SECONDARY AXIS OF WEAK CONVERGENCE DEVELOPS ALONG THE COASTAL PLAIN
IN ASSOCIATION WITH A SURFACE TROUGH. FORECAST SOUNDINGS SHOW VERY
DRY MID LEVELS AND SO MEASURABLE PRECIPITATION SEEMS QUITE UNLIKELY
BUT A SLIGHT CHANCE WILL BE CARRIED ALONG COASTAL ZONES IN THE EVENT
OF A STRAY 0.01". WHAT LITTLE CAA BEHIND THE BOUNDARY THERE HAD
BEEN ON WED WILL BE GONE BY THURS AND TEMPS TO BE BACK A FEW DEGREES
ABOVE CLIMO. MORE APPRECIABLE FRONT TO COME THROUGH EITHER THURSDAY
NIGHT OR FRIDAY MORNING DEPENDING ON MODEL CHOICE. GIVEN THE STRONG
SURFACE PRESSURE ADVECTION PUSHING IT PREFER THE QUICKER TIMING I.E.
WRF. FRIDAY HIGHS KNOCKED BACK DOWN A FEW DEGREES BELOW CLIMO AND
DEWPOINTS TO FALL INTO THE MID OR EVEN LOW 60S...THE LATTER MOST
LIKELY OVER NW ZONES. FAR SRN SC ZONES MAY HOLD ON TO DEWPOINTS IN
THE UPPER 60S. INTERESTING SKY COVER FORECAST LATE FRIDAY INTO
FRIDAY NIGHT AS GUIDANCE SHOWING SOME ATLANTIC MOISTURE ASSOC WITH
THE NE SURGE. MID LEVELS REMAIN VERY DRY...PROBABLY DRIER THAN FCST
SOUNDINGS SHOW IN THE CONTINUED NW FLOW...AND WITH NO NOTICEABLE
FRONTAL INVERSION THIS MOISTURE MAY NOT GET TRAPPED AS MUCH AS THE
RELATIVELY CLOUDY GUIDANCE IMPLIES.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...VERY QUIET WEATHER ON TAP FOR THE PERIOD.
UPPER RIDGE REMAINS ACROSS THE PLAINS THROUGH SUNDAY OR MONDAY WHILE
SURFACE HIGH CONTINUES TO BUILD IN FROM THE NORTH. MONDAY INTO
TUESDAY WILL BRING THE UPPER RIDGE EASTWARD IN A WEAKENING STATE.
THE SURFACE HIGH WILL SHIFT SLIGHTLY EASTWARD AS WELL BUT NOT ENOUGH
FOR SUFFICIENT MOISTURE FLUX LOCALLY. TEMPERATURES NEAR CLIMO EARLY
IN THE PERIOD WITH JUST A VERY SLOW RISE THROUGHOUT AS A RESULT OF
SOLAR MODERATION AS OPPOSED TO ANY THERMAL ADVECTION.
&&
.AVIATION /12Z WEDNESDAY THROUGH MONDAY/...
AS OF 12Z...FRONT IS LINGERING OVER THE SOUTHERN PORTION OF THE
CWA. PWATS HAVE COME DOWN...BUT ARE STILL RANGING IN THE 1.5-1.9"
RANGE. SHOULD SEE SOME ISOLATED CONVECTION NEAR THE MYRTLES AROUND
MAX HEATING. WINDS WILL BE PREDOMINATELY NORTHEAST OVER THE
NORTHERN PORTION OF THE CWA...AND VARIABLE OVER THE SOUTHERN
PORTION. THE COAST WILL LIKELY SEE A SEA BREEZE RESULTANT BY
18-19Z. TONIGHT...GOOD RADIATIONAL COOLING CONDITIONS WILL BRING
IN THE CHANCE FOR FOG AFTER 08Z. INLAND TERMINALS STAND THE BEST
CHANCE FOR IFR CONDITIONS.
EXTENDED OUTLOOK...MORNING FOG/STRATUS IS POSSIBLE THROUGH THE
EXTENDED PERIOD. OTHERWISE VFR CONDITIONS SHOULD PREVAIL.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM WEDNESDAY...WEAK COLD FRONT HAS MOVED SOUTH AND EAST
OF THE OF THE WATERS THIS MORNING AND WILL BE FOLLOWED BY WEAK
OFFSHORE FLOW. DIFFUSE GRADIENT BEHIND THE FRONT WILL ALLOW
DEVELOPMENT OF AFTERNOON SEA BREEZE. THIS WILL LEAD TO STRONGEST
WINDS OVER THE NEAR SHORE WATERS WITH LIGHTER WINDS AWAY FROM
SHORE. SPEEDS WILL STRUGGLE TO EXCEED 10 KT BUT ISOLATED GUSTS IN
THE AFTERNOON TO 15 KT WILL BE POSSIBLE. DISSIPATION OF SEA BREEZE
CIRCULATION THIS EVENING WILL RESULT IN WINDS BECOMING LIGHT AND
VARIABLE OVERNIGHT. SEAS WILL RUN 2 TO 3 FT THROUGH THE PERIOD.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...EVEN THOUGH A FRONT WILL BE STALLED AND
WEAKENING NOT FAR TO THE SOUTH ON THURSDAY THE FLOW WILL TURN BACK
AROUND TO A SOUTHERLY DIRECTION AS SURFACE TROUGHINESS DEVELOPS JUST
INLAND FROM THE COAST. IT WILL BE A VERY LIGHT FLOW WITH SPEEDS
GENERALLY CAPPED AT 10KT RESULTING IN 2 FT SEAS. A FAIRLY QUICK VEER
TO THE NORTH IS SLATED FOR THURSDAY NIGHT ALTHOUGH SOME LESS FAVORED
MODEL SOLUTIONS ARE SLOWER. A RELATIVELY STRONG HIGH WILL BUILD IN
BEHIND THE THURSDAY NIGHT FRONT AND WIND SPEEDS MAY INCREASE A
CATEGORY OR MORE BUILDING SEAS INTO THE 2 TO 4 FT RANGE...A LITTLE
LOWER OVER SRN ZONES.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...ANY RESIDUAL VESTIGE OF THE SURGE FROM THE
SHORT TERM SHOULD QUICKLY ABATE AS SATURDAY WEARS ON AS HIGH
PRESSURE BECOMES CENTERED OFF OF NEW ENGLAND/MID ATLANTIC AND
EXTENDS RIDGE AXIS INTO THE CAROLINAS. WINDS WILL BE ONSHORE EITHER
E OR NE AND FALL TO 10 KTS ALLOWING SEAS TO SETTLE TO 2 FT. A PIECE
OF THE HIGH BREAKS OFF AND STAYS BEHIND ACROSS THE CAROLINAS ON
SUNDAY CONTINUING THE TREND OF VERY LIGHT ONSHORE WIND AND SEAS
CAPPED AT 2 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC
NEAR TERM...MJC
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...DL
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1241 PM CDT WED SEP 4 2013
.UPDATE...
ISSUED AT 1241 PM CDT WED SEP 4 2013
PRECIPITATION HARD TO COME BY AFTER MAIN AREA OF HIGH BASED SHOWERS
SHIFTED SOUTH OF THE CWA EARLIER THIS MORNING. FAIRLY EASY TO TELL
WHERE ANY POTENTIAL WOULD BE BASED ON NARROW BAND OF CLOUDS/SPOTTY
ECHOES ON REGIONAL RADAR. SIMILAR TO YESTERDAY...THIS AREA LINES UP
WELL WITH MID LEVEL THETA-E GRADIENT/ADVECTION. HOWEVER...AIRPORT
OBSERVATIONS BENEATH A COUPLE OF AREAS OF ECHOES LITTLE IF ANY RAIN
REACHING THE GROUND DUE TO DRY AIR BELOW ABOUT 8-9KFT...SO REMOVED
MOST POPS FROM THE REMAINDER OF THE AFTERNOON INTO THIS EVENING.
WEAK LOW LEVEL JET MAY ASSIST SPOTTY DEVELOPMENT OVERNIGHT SO HAVE
KEPT ISOLATED POPS IN FOR TONIGHT SO FAR. HOWEVER MID LEVEL SUPPORT
SEEMS TO WANE AS ALREADY WEAK WAVE SHEARS OUT AND FLOW BECOMES LESS
CONVERGENT...SO WILL REEVALUATE THESE POPS BEFORE AFTERNOON PACKAGE
IS FINALIZED.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CDT WED SEP 4 2013
CURRENTLY SEEING SOME SCATTERED SHOWERS AND A FEW THUNDERSTORMS
ACROSS SOUTH CENTRAL SOUTH DAKOTA. IN GENERAL EXPECT THE COVERAGE OF
THESE SHOWERS TO DECREASE DURING THE MORNING AS WE LOSE THE LOW
LEVEL JET. HOWEVER...A WEAK MID LEVEL WAVE WILL REMAIN IN THE AREA
THROUGH THE DAY...WITH DECENT MID LEVEL MOISTURE AND SOME THETAE
ADVECTION. THUS WILL KEEP SLIGHT CHANCE POPS THROUGH THE
DAY...MAINLY FROM JUST EAST OF THE INTERSTATE 29 CORRIDOR AND POINTS
WEST. DRY AIR IN THE LOWER LEVELS SHOULD MAKE IT TOUGH FOR MUCH OF
THIS MID LEVEL ACTIVITY TO REACH THE GROUND...BUT DO THINK A FEW
SHOWERS ARE POSSIBLE. THE HRRR IS MOST AGGRESSIVE WITH THE
ACTIVITY...AND WHILE IT SEEMS OVERDONE...IT DOES GIVE ANOTHER REASON
TO KEEP THE SLIGHT CHANCE POPS. INSTABILITY IS MARGINAL...BUT GIVEN
THE HIGH BASED NATURE OF THESE STORMS THERE MAY BE JUST ENOUGH TO
GET A LIGHTNING STRIKE OR TWO WITH THE SHOWERS EVERY ONCE IN A
WHILE...SO KEPT THUNDER IN FOR NOW. HIGH TEMPERATURES TODAY SHOULD
BE IN THE 80S...WITH THE CLOUD COVER PREVENTING FULL HEATING FOR
MOST OF THE AREA. MUCH OF THE SAME TONIGHT...WITH THE MID LEVEL WAVE
IN THE VICINITY...EXPECTING A MOSTLY CLOUDY NIGHT. COULD SEE A
SLIGHT UPTICK IN SHOWER ACTIVITY THE FIRST PORTION OF THE NIGHT AS
THE LOW LEVEL JET GETS GOING...BUT NOT REAL CONFIDENT IN THAT. THUS
WILL KEEP JUST SLIGHT CHANCE POPS FOR NOW. EITHER WAY NOT EXPECTING
MUCH. DID RAISE LOWS SOME WITH THE NEWER GUIDANCE COMING IN A BIT
WARMER...SUGGESTING ANY COOLER AND DRYER LOW LEVEL AIR STAYS
NORTHEAST OF THE CWA. GENERALLY LOOKING FOR LOW TO MID 60S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 338 AM CDT WED SEP 4 2013
AN UPPER LEVEL WAVE AND A WEAK MID LEVEL BOUNDARY COULD SPARK A FEW
SHOWERS OVER THE FAR EASTERN CWA ON THURSDAY BUT WITH FAIRLY DRY LOW
LEVELS AND WEAK MID LEVEL INSTABILITY NO PLAN TO ADD ANY POPS AS
WHATEVER COULD DEVELOP WOULD REMAIN ON THE LIGHT SIDE. AS THE WAVE
EXITS WILL BE A BIT OF A EASTERLY COMPONENT TO THE WIND SO WHILE THE
DAY WILL BE WARM EXPECT NO MAJOR MIXING. HIGHS MAINLY IN THE LOWER
TO MID 80S.
THURSDAY NIGHT INTO FRIDAY WILL SEE A TIGHTENING OF THE GRADIENT AND
AN INCREASE IN THE LOW LEVEL TEMPERATURE FIELD. THIS WILL LEAD
TOWARDS WARM LOWS IN THE MID AND UPPER 60S AND HIGHS ON FRIDAY WELL
INTO THE 90S WITH SOMETHING AROUND 100 POSSIBLE IN CENTRAL SOUTH
DAKOTA.
A STRONG RIDGE OF HIGH PRESSURE WILL BE IN PLACE FOR MUCH OF THE
PERIOD...THEN SOME HINTS THAT IT SHOULD BREAK DOWN A BIT EARLY NEXT
WEEK AS A WEAK SHORTWAVE MOVES THROUGH THE NORTHERN ROCKIES AND INTO
THE NORTHERN PLAINS. OVERALL THE MODELS ARE IN PRETTY GOOD AGREEMENT
WHICH SUGGESTS VERY WARM READINGS SATURDAY THROUGH MONDAY...WITH THE
HOTTEST TEMPERATURES LIKE FRIDAY AND SATURDAY AHEAD OF A WEAK
BOUNDARY THAT IS PROGGED TO LEAK SOUTHWARD INTO THE AREA. NOT MUCH
PUNCH FROM THIS BOUNDARY AS THE WAVE THAT IS FORCING IT SOUTH IS
MOVING SOUTHEAST THROUGH THE GREAT LAKES REGION. THE RIDGE
REESTABLISHES AGAIN ON MONDAY AS THE WEAK WAVE MOVES ONTO THE PLAINS
AND TRIES TO BRING A BOUNDARY INTO THE AREA ON TUESDAY. IF THIS WAVE
IS A LITTLE SLOWER TUESDAY COULD PROVE TO BE VERY WARM AS WELL. WILL
CONFINE POPS TO THE TIMING OF THE TWO FRONTS WHICH SHOULD MAINLY BE
SATURDAY NIGHT INTO SUNDAY AND MONDAY NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1241 PM CDT WED SEP 4 2013
VFR CONDITIONS THROUGH THE PERIOD. ISOLATED SHRA OR TSRA REMAIN
POSSIBLE...THOUGH WITH SPOTTY NATURE AND DRY AIR BENEATH MID LEVEL
CLOUD BASE LIMITING PRECIP EVEN REAACHING THE GROUND...HAVE LITTLE IF
ANY MENTION IN THE TAFS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...JH
SHORT TERM...CHENARD
LONG TERM...08
AVIATION...JH
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1212 PM CDT WED SEP 4 2013
.DISCUSSION...
18Z TAF DISCUSSION IN AVIATION SECTION...
&&
.AVIATION...
KCLL/KUTS/KCXO...OVERALL VFR CIGS WITH LIGHT EAST WINDS. SHOULD
HAVE TCU THIS AFTERNOON AND TOMORROW BUT TERMINALS MAY BE ON EDGE
OF HIGHER MOISTURE FOR CONVECTION TO FORM. CONVECTION STILL
POSSIBLE BUT CONFIDENCE RATHER LOW AT THIS TIME.
KIAH/KHOU/KSGR...WILL CARRY VCSH/VCTS FOR TERMINALS THIS
AFTERNOON AND TOMORROW AFTERNOON. THINK BEST CHANCES FOR TSRA ARE
THIS AFTERNOON WITH HEATING AND CONVERGENCE ON SEA BREEZE OR
OUTFLOW FROM MORNING CONVECTION ALONG THE COAST. HRRR SEEMS TO
HAVE A GOOD HANDLE ON THIS. WILL AMMEND TAFS IF CONVECTION AFFECTS
TERMINALS BUT NOT HIGH ENOUGH CONFIDENCE TO PUT IN TAFS NOW. SAME
WILL BE SAID FOR TOMORROW AFTERNOON.
KLBX/KGLS...CONVECTION THIS MORNING HAS WEAKENED AND NOT EXPECTED
MUCH MORE ACTIVITY THIS AFTERNOON AS SEA BREEZE MOVES INLAND.
EXPECT ANOTHER ROUND OF SHOWERS IN THE MORNING FOR KGLS WHICH
COULD AFFECT KLBX. FOR NOW WILL WAIT AND SEE AS STILL PLENTY OF
TIME TO UPDATE TAFS IF CONVECTION BECOMES MORE WIDESPREAD IN THE
MORNING.
39
&&
.PREV DISCUSSION... /ISSUED 1124 AM CDT WED SEP 4 2013/
DISCUSSION...
STORMS RIGHT ALONG THE COAST PERSISTING BUT WE ARE SEEING SIGNS OF
WEAKENING. OTHERWISE NOT A LOT OF CHANGES (IF ANY) FOR THIS UPDATE
WITH THE GOING FCST OF ISO/WIDELY SCT PCPN FOR THE REST OF THE AF-
TERNOON. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 99 76 98 75 98 / 20 10 20 10 20
HOUSTON (IAH) 99 76 97 76 96 / 30 10 20 10 20
GALVESTON (GLS) 90 81 90 80 89 / 30 20 30 20 30
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...41
AVIATION/MARINE...39
AREA FORECAST DISCUSSION
NWS SPOKANE WA
258 PM PDT Wed Sep 4 2013
.SYNOPSIS...
Showers and thunderstorms will increase over the Inland Northwest
tonight into Thursday as a Pacific low pressure system approaches
the region. Some storms could be severe especially on Thursday.
Heavy rainfall will also be a concern especially for burn scar
areas along the East Slopes of the Cascades. The low pressure
system will move across the region on Friday and through the
weekend, resulting in much cooler temperatures with continued
showers and a chance for mountain thunderstorms. A significant
drying and warming trend is expected after Monday through much of
the upcoming week.
&&
.DISCUSSION...
Tonight: The moist southerly flow will continue over the Inland
Northwest. Afternoon and early evening convection will be limited
to the higher terrain of the northern mountains and the Blue
mountains where we can expect the surface based convection to
develop. Not much in a way of a trigger to fire off the
convection, despite our building low level instability. The GFS
and NAM are having issues on grasping the small scale features to
ignite the convection, and the HRRR seems to indicate not much
will happen during the time of peak heating. The high resolution
NAM does show nocturnal convection tracking north from Oregon and
reaching area late tonight and have adjusted my pops and weather
to that idea. Overnight lows will remain mild as low level
moisture and dewpoints continue to increase. /rfox.
...VERY WET AND STORMY WEATHER PATTERN THROUGH THE END OF THE WORK
WEEK WITH HEAVY, STRONG OUTFLOW WINDS AND HAIL A CONCERN WITH THUNDERSTORMS...
Thursday through Friday night: A deep upper level low pressure
system spinning off the Pac NW coastline will slowly begin to push
into the region. As this system does so, multiple waves of energy
will pivot around with widespread rain showers and thunderstorms
expected. Rain showers with some embedded thunderstorms will be
lingering across the region through Thursday afternoon, mainly
across the northern portions of the forecast area. Looks like we
should see a short break in the storms across the basin in the
afternoon. This is expected to result in some sun breaks across
the basin, which will further destabilize the atmosphere before
the strongest impulse of energy will pivot across OR and into WA
by the evening hours. Models are showing strong upper level
dynamics with this next wave and steep mid level lapse rates of
roughly 7.5 C/KM. Pwats will continue to increase to up over 1.4
inches, which is 200% plus of normal. The 4km NAM simulated radar
reflectivity continues to show a convective system that rapidly
forms in southern WA and expands northward through the evening.
Sounding profiles across the region would support the possibility
for some large hail and strong winds with the thunderstorms that
develop Thursday evening.
A second impulse is expected to move into the region relatively
quickly behind the one for Thursday night pushing in Friday
morning into Friday afternoon. This will result in little relief
of the soaking rain across the region, especially for the northern
mountains and in the Cascades. This second impulse will not see as
strong stability profiles for severe thunderstorms. However, we
will remain in a very moist atmosphere with convective showers and
thunderstorms expected to bring continued heavy rainfall. 36 hour
rainfall totals from Thursday afternoon into Friday evening are
expected to be up around 1-2 inches possible for the northern
mountains over into the Cascades with some locally higher amounts
where multiple thunderstorms pass through. With the barrage of
heavy rainfall possible in the northern mountains over to the
Cascades and onto Waterville Plateau, we decided that we will
expand the Flash Flood Watch to cover all these areas. Recent 2012
and 2013 burn scar will be most susceptible to flash flooding, but
rainfall rates will be high enough for other non burned scared
areas as well; this will be especially so in steeper terrain. Mud
slides and debris flows will also be possible with this event.
Temperatures will trend much colder Thursday into Friday as the
cold upper level low pressure system nudges over the region.
High temperatures on Friday will be 10 to 15 degrees below normal.
/SVH
Saturday through Sunday night...Cooler and unsettled weather will
prevail across the Inland Northwest for the weekend as an upper
level low drifts over the region. Southwest flow around the eastern
flank of the low will place the focus for showers over the eastern half
of the forecast area. Pwats will continue to be in the range of 125
to 175 percent of normal. This deep moisture fetch will bring
wetting rains to much of the forecast area, but especially to the
northeast mountains of WA and the northern panhandle of Idaho. The
main forcing mechanism will come from upper level dynamics in the
base of the trough along with orographics. Models have some weak
surface based instability during the afternoon and evening hours but
this will depend on whether there are any breaks in the overcast. By
Sunday the GFS shows much less areal coverage of showers as it has
the upper low moving east to northwest Montana, placing more stable
air over eastern WA and mainly upslope flow driving the showers in
north ID. The ECMWF is slower moving the low to the east so some
residual showers remain in the forecast for Sunday night, mainly for
the panhandle mountains.
Daytime temperatures will be on the cool side, with most valley
locations in the 70s Saturday, then warming from west to east
Sunday. Overnight low will be mild, due to precipitation and cloud
cover. As the low moves east, more stable northerly flow could allow
for some fog development across the northeast valleys. /Kelch
Monday afternoon through Wednesday night...If the extended models
hold true to their latest solutions, the wet storm system that
will have lingered over the Inland Northwest will have exited the
region. Another ridge looks to rebound once again, although the
exact strength and location is a little more up in the air. While
this will promote a warming and drying trend, the upcoming
rainfall event may tend to keep temperatures from getting too out
of hand during each afternoon. The moist ground will also combine
with afternoon heating for scattered clouds, which would also act
to keep the region from reaching its full afternoon high
potential. Obviously areas that don`t receive as much rainfall
will have a better chance to dry out quicker, and the temperatures
will be higher. But overall, the main change to this portion of
the forecast was to shave off a few degrees from the high
temperatures each day, but keeping with the warm-up through
Wednesday.
Fog may also become an issue each night, at least over the
northern valleys, but possibly reaching further south as well.
While this isn`t included in the wording of the forecast, it is
something that we can fine tune after this weeks rain event. ty
&&
.AVIATION...
18Z TAFS: Moist and unstable southerly flow will continues over
the region. During the afternoon and evening hours surface based
instability will once again create a chance of thunderstorms over
the mountains around the basin and over the eastern basin
threatening the KGEG area sites and KPUW and KLWS. A few of these
storms may be strong or severe with large hail and strong wind
gusts. Then overnight elevated moisture and instability increases
with all areas having a chance for thunderstorms after 09z and
into Thursday morning. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 65 78 56 64 54 70 / 60 80 100 70 40 40
Coeur d`Alene 62 79 57 65 54 70 / 60 80 90 70 40 50
Pullman 62 78 55 66 48 72 / 60 80 90 50 20 20
Lewiston 68 84 61 73 59 80 / 60 80 80 40 20 10
Colville 59 80 58 66 51 74 / 60 80 100 80 70 50
Sandpoint 59 79 56 65 49 69 / 60 80 90 80 50 50
Kellogg 59 79 54 65 51 71 / 60 80 90 70 50 50
Moses Lake 65 80 58 69 54 76 / 70 80 90 60 30 10
Wenatchee 65 75 59 68 56 74 / 70 90 90 70 50 10
Omak 64 78 59 67 55 76 / 60 80 90 90 70 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Flash Flood Watch from late tonight through Friday afternoon for
Northern Panhandle.
WA...Flash Flood Watch from late tonight through Friday afternoon for
Northeast Mountains.
Flash Flood Watch from 2 AM PDT Thursday through Friday
afternoon for East Slopes Northern Cascades-Okanogan
Highlands-Okanogan Valley-Waterville Plateau-Wenatchee Area.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
337 PM CDT WED SEP 4 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 337 PM CDT WED SEP 4 2013
MAIN FORECAST CONCERNS IN THE SHORT TERM ARE ON TEMPERATURES AND
CLOUD COVER TONIGHT INTO THURSDAY MORNING.
LATEST WATER VAPOR IMAGERY AND 500 MB RAP ANALYSIS SHOWED RIDGING
ACROSS ANCHORED OVER THE ROCKIES. TWO UPPER LOWS NOTED...ONE
CENTERED OVER THE EASTERN SHORE OF HUDSON BAY...AND THE OTHER WAS
JUST EDGING INTO THE PACIFIC NORTHWEST. A WEAK COLD FRONT
STRETCHED FROM CENTRAL MINNESOTA ACROSS CENTRAL WISCONSIN EAST
THROUGH NORTHERN LOWER MICHIGAN AND WAS SLOWLY DRIFTING SOUTH.
THERE HAS NOT BEEN ANY PRECIPITATION ASSOCIATED WITH THE FRONT
JUST A SLIGHT INCREASE IN CLOUD COVER.
SURFACE HIGH PRESSURE WILL BUILD INTO THE FORECAST AREA TONIGHT AS
THE COLD FRONT SLIDES SOUTH INTO CENTRAL IOWA AND SOUTHERN ILLINOIS.
THE STRATUS CURRENTLY OVER NORTHERN WISCONSIN...SLIPS SOUTHWEST
TONIGHT. LINGERING MOISTURE CENTERED AROUND 850 MB...WITH AN
ADDITIONAL POCKET LOCATED IN THE 700-450 MB LAYER...MAY BE ENOUGH TO
GENERATE SOME CLOUD COVER TONIGHT OVER NORTHEAST IOWA....SOUTHEAST
MINNESOTA...AND SOUTHWEST WISCONSIN. FORECAST SOUNDINGS SUGGEST THE
LOWER LEVEL MOISTURE WILL DRY OUT AS THE HIGH BUILDS IN. IF THE
CLOUD COVER LINGERS IT WILL HAVE AN IMPACT ON FOG POTENTIAL AND
TEMPERATURES OVERNIGHT. PLAN ON PARTLY CLOUDY TO MOSTLY CLEAR SKIES
TONIGHT WITH LOW TEMPERATURES RANGING FROM THE UPPER 30S TO LOWER 40S
OVER NORTHERN WISCONSIN TO THE MID TO UPPER 50S ACROSS NORTHEAST
IOWA.
HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON THURSDAY
PROVIDING DRY AND QUIET WEATHER. THE MAIN CONCERN WILL BE ON
AFTERNOON DEWPOINTS...ESPECIALLY CLOSER TO THE CENTER OF THE HIGH
OVER CENTRAL INTO NORTH CENTRAL WISCONSIN. FORECAST SOUNDINGS SHOW
DRY AIR ALOFT WITH DEEP MIXING TO NEARLY 875 MB. LOOKING UPSTREAM
ACROSS UPPER MICHIGAN AND SOUTHERN ONTARIO...DEWPOINTS ARE ONLY IN
THE UPPER 30S TO LOWER 40S AND THIS AIR IS ADVECTING SOUTHWARD. HAVE
LOWERED AFTERNOON DEWPOINTS INTO THE LOWER 40S OVER WEST CENTRAL
THROUGH CENTRAL WISCONSIN WHERE DEEP MIXING SHOULD EASILY YIELD THESE
AFTERNOON VALUES. THIS WOULD PRODUCE RELATIVE HUMIDITY VALUES IN
THE 27 TO 30 PERCENT RANGE. THERE WILL NOT BE MUCH WIND UNDER THE
HIGH WITH WIND MAINLY LIGHT AND VARIABLE AT 5 MPH OR LESS OVER THESE
AREA. OTHERWISE...PLAN ON SKIES RANGING FROM PARTLY TO MOSTLY CLOUDY
OVER SOUTHEAST MINNESOTA INTO NORTHEAST IOWA...TO MOSTLY SUNNY OVER
NORTH CENTRAL WISCONSIN. A WEAK SHORTWAVE LOOKS TO MOVE ACROSS AREAS
ALONG AND WEST OF THE MISSISSIPPI RIVER WITH THE MAIN IMPACT BEING
AN INCREASE IN CLOUD COVER.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 337 PM CDT WED SEP 4 2013
THE HIGH WILL SLIDE EAST INTO THE EASTERN GREAT LAKES THURSDAY NIGHT
INTO FRIDAY. A COLD FRONT IS EXPECTED TO PUSH INTO NORTHWEST
MINNESOTA AND EASTERN SOUTH DAKOTA BY FRIDAY AFTERNOON. SOUTHERLY
FLOW WILL INCREASE ACROSS THE AREA ON FRIDAY AS THE FRONT APPROACHES
HELPING TO USHER IN A WARMER AND SLIGHTLY MORE HUMID AIRMASS. 925 MB
TEMPERATURES WARM TO AROUND 25 ACROSS WESTERN AND CENTRAL WISCONSIN
AND TO THE UPPER 20S ACROSS PORTIONS OF NORTHEAST IOWA AND SOUTHEAST
MINNESOTA. HIGH TEMPERATURES ARE EXPECTED TO WARM INTO THE MID
80S...WITH A FEW UPPER 80S POSSIBLE ALONG THE MISSISSIPPI RIVER
VALLEY AND CLOSER TO THE INTERSTATE 35 CORRIDOR. FORECAST MODELS ARE
ADVERTISING A WEAK SHORTWAVE MOVING ACROSS THE EASTERN DAKOTAS AND
PUSHING INTO THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY NIGHT
INTO EARLY FRIDAY MORNING. 850 MB MOISTURE TRANSPORT IS WEAK AND
FOCUSED INTO SOUTHWEST MINNESOTA AND WESTERN IOWA THURSDAY EVENING
THEN ATTEMPTS TO SHIFT EAST INTO THE AREA EARLY FRIDAY MORNING.
THERE ISN/T MUCH UPPER LEVEL SUPPORT FOR PRECIPITATION SO DECIDED TO
MAINTAIN A DRY FORECAST DURING THIS TIMEFRAME. THE FRONT IS EXPECTED
TO PUSH SOUTHEAST FRIDAY NIGHT INTO SATURDAY POSSIBLY INTERACTING
WITH WEAK UPPER LEVEL IMPULSES IN NORTHWEST FLOW ALOFT. THIS WILL
BRING SLIGHT CHANCES FOR SHOWERS AND STORMS TO THE FORECAST AREA
FRIDAY NIGHT INTO SATURDAY. THE PACIFIC NORTHWEST TROUGH FINALLY
MOVES EAST ACROSS THE NORTHERN PLAINS SUNDAY NIGHT THROUGH MONDAY
NIGHT BREAKING DOWN THE PERSISTENT RIDGING OVER THE UPPER MIDWEST.
THIS WILL BRING CHANCES FOR SHOWERS AND STORMS TO THE FORECAST
AREA...ESPECIALLY SUNDAY NIGHT INTO MONDAY NIGHT. WARM SOUTHERLY
FLOW WILL CONTINUE INTO EARLY NEXT WEEK. HIGHS WILL REMAIN WELL
ABOVE NORMAL THROUGH THE WEEKEND WITH SATURDAY LOOKING TO BE THE
WARMEST DAY WITH HIGHS IN THE MID TO UPPER 80S. THE WARM
TEMPERATURES WILL CONTINUE THROUGH THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1242 PM CDT WED SEP 4 2013
FOCUS IS ON MVFR STRATUS OVER NORTHEAST WISCONSIN...SITUATED
BEHIND A COLD FRONT LOCATED NEAR I-94. THIS COLD FRONT IS SLATED
TO COME THROUGH THE TAF SITES IN THE NEXT FEW HOURS...FOLLOWED BY
A GRADUAL WIND SHIFT THROUGH THE LATE AFTERNOON AND EVENING HOURS
FROM NORTHWEST TO NORTHEAST. VFR CONDITIONS ARE EXPECTED UNTIL THE
WINDS TAKE ON THAT MORE EASTERLY COMPONENT. AT THAT TIME...STRATUS
SHOULD EITHER DEVELOP OR ADVECT IN FROM THE STRATUS CURRENTLY OVER
NORTHEAST WISCONSIN. APPROXIMATE TIMES OF THIS OCCURRING IN THE
TAFS ARE 08Z AT LSE AND 10Z AT RST. THESE MAY NEED TO BE ADJUSTED
PER OBSERVATION AND SATELLITE TRENDS. ADDITIONALLY...CEILINGS
CURRENTLY FORECAST ARE MVFR AT LSE AND IFR AT RST...BUT IT IS
EASILY POSSIBLE THESE COULD END UP 1 OR 2 CATEGORIES LOWER AT
BOTH SITES. THIS TOO NEEDS TO BE MONITORED. LASTLY...CANNOT RULE
OUT SOME FOG FORMING AT RST TOO IF THIS STRATUS DOES INDEED
MANIFEST ITSELF WITH A LOWER CEILING. DAYTIME HEATING PLUS DRY AIR
ADVECTING IN FROM THE NORTH SHOULD HELP SCATTER OUT THE STRATUS BY
16Z THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1233 PM CDT WED SEP 4 2013
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SYNOPSIS...
ISSUED AT 339 AM CDT WED SEP 4 2013
DRY WITH SEASONABLE TEMPERATURES EARLY...THEN BECOME WARMER AND
MORE HUMID AGAIN THIS WEEKEND AND EARLY NEXT WEEK.
THE MAIN BAND OF WESTERLIES WAS ACRS CANADA...AND WL REMAIN SO
THROUGHOUT THE PERIOD. WITHIN IT...LNGWV RIDGE POSN WL BE OVER WRN
CANADA...WITH A TROF IN THE E. A SHOT OF COLD AIR FM NRN CANADA WL
LEAD TO SOME AMPLIFICATION OF THE ERN TROF EARLY...THEN THE TEND
SHOULD BE FOR A GRADUAL FLATTENING OF THE FLOW. MEANWHILE ACRS THE
CONUS...THE LARGE SCALE WL BE DOMINATED BY SPRAWLING ANTICYCLONE
CURRENTLY CENTERED OVER THE CEN/SRN ROCKIES AND HIGH PLAINS. A
CLOSED UPR LOW OFF THE PAC NW COAST WL EVENTUALLY START TO WORK
ITS WAY E. THAT WL PROBABLY CAUSE THE UPR HIGH TO SHIFT E TOWARD
THE MISSISSIPPI VALLEY LATE IN THE WEEKEND AND NEXT WEEK.
OVERALL...THIS IS A PRETTY TYPICAL UPR PATTERN FOR EARLY AUTUMN.
THE NWLY UPR FLOW ALONG THE SRN EDGE OF THE WESTERLIES WL BE STG
ENOUGH TO SUPPRESS THE VERY WARM/HUMID AIR S OF THE FCST AREA FOR
THE FIRST PART OF THE FCST PERIOD...BUT AS THE FLOW DEAMPLIFIES
AND THE UPR HIGH SHIFTS E...SOME HEAT AND HUMIDITY WL PROBABLY
RETURN TO THE AREA. THE TEMPERATURE ROLLER COASTER WL CONT AT THE
START OF THE FCST PERIOD...WITH WARMER AIR ACRS THE AREA TDA
REPLACED BY COOLER CONDITIONS FOR THE NEXT COUPLE DAYS. THEN TEMPS
SHOULD HEAD BACK TO ABV NORMAL LEVELS BY THE WEEKEND AND WL
PROBABLY STAY THERE NEXT WK. HUMIDITIES WL ALSO BE ON THE
INCREASE. DRY WX WL CONT FOR A FEW MORE DAYS...THEN PCPN CHCS WL
RETURN ONCE THE HEAT AND HUMIDITIY DOES.
&&
.SHORT TERM...TODAY...TONIGHT...AND THURSDAY
ISSUED AT 339 AM CDT WED SEP 4 2013
OVERALLY A PRETTY QUIET PERIOD...THOUGH LOTS OF FCST DETAILS TO
SORT OUT. WELL DEFINED COLD FRONT WAS SURGING SWD ACRS THE LAKE
SUPERIOR RGN EARLY THIS MORNING. WAA/MIXING WITH TIGHTENING
PRESSURE GRADIENT WAS CAUSING TEMPS TO RISE AHEAD OF THE FRONT
DESPITE IT BEING NIGHTTIME...WITH SXHW3 ACTUALLY UP TO 72 F AT ONE
POINT. MODELS WERE TURNING THE SFC WINDS NW AHEAD OF THE ACTUAL
FRONT...AND THUS SEEMED TO BE HAVING TROUBLE MAINTAINING THE
IDENTIFY OF THE FRONT. THE RAP SEEMS TO BE HANDLING THE SITN ABOUT
THE BEST. DESPITE AN ANTICIPATED STG SWD PUSH OF THE FRONT /THERE
ARE CURRENTLY 5 MB 3-HR PRESSURE RISES ON ERN LAKE SUPERIOR/
CURRENT POSN OF THE FRONT SUGGESTS DELAYING ITS ARRIVAL A BIT.
THAT SHOULD ALLOW TEMPS ACRS THE SRN PART OF THE FCST AREA TO WARM
QUICKLY THIS MORNING. RAISED MAXES THERE.
FRONT WL SURGE SWD DOWN THE BAY/LAKESHORE...BUT MAY SLOW OVER THE
SW PART OF THE FCST AREA. SOME LOW-LEVEL MOISTURE IS POOLED ALONG
THE BOUNDARY BACK TO THE W. THAT WL PROBABLY MAKE IT INTO CENTRAL
WI MID-DAY. GIVEN THE CONVERGENCE ALONG THE FRONT...STARTING TO
HAVE CONCERNS THAT AN ISOLD SHRA/TSRA COULD DEVELOP OVER THE SW
CORNER OF THE FCST AREA THIS AFTN. NOT ENOUGH SUPPORT TO ADD TO
THE FCST YET...BUT TRENDED POPS UP TO SILENT 14/S OVER THE SW.
COOLER AND DRIER AIR WITH CANADIAN HIGH WL BECOME ESTABLISHED
ACRS THE AREA TNGT. COULD SEE A FEW CLDS COME OFF THE BAY LATE.
OTHERWISE...EXPECT MAINLY CLR SKIES. WITH WINDS LIKELY DYING OFF
LATE TNGT ACRS THE N...EXPECT THE TYPICAL COLD SPOTS TO DROP INTO
THE 30S. PATCHY FROST IS POSSIBLE IN THESE AREAS BY MORNING.
PLENTY OF SUN IS EXPECTED THU AS HIGH PRESSURE DOMINATES. ELY
FLOW WL KEEP THE LAKESHORE A LITTLE COOLER...BUT DRY AIR SHOULD
ALLOW FOR TEMPS AT MOST LOCATIONS TO REACH AOA NORMAL LEVELS
DESPITE THE CHILLY START TO THE DAY IN THE N.
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY
ISSUED AT 339 AM CDT WED SEP 4 2013
NORTHWEST FLOW WILL CONTINUE INTO THE WEEKEND AS 500MB RIDGE
REMAINS ANCHORED ACROSS THE CENTRAL PLAINS. THE 500MB RIDGE SHOULD
SHIFT EAST EARLY NEXT WEEK...THEN BREAK DOWN AS UPPER TROUGH
SWINGS ACROSS THE NORTHERN UNITED STATES. BEYOND THE FORECAST
PERIOD...500MB RIDGE IS EXPECTED TO BUILD ACROSS THE WESTERN
UNITED STATES WITH A NORTHWEST FLOW PATTERN TO BE REESTABLISHED
ACROSS THE WESTERN LAKES.
MODELS CONTINUE TO STRUGGLE AMONGST THEMSELVES AND FROM MODEL RUN
TO RUN ON WHERE TO FOCUS PRECIPITATION THURSDAY NIGHT INTO FRIDAY.
THIS IS ESPECIALLY TRUE FOR THE ECMWF...WHICH TYPICALLY TRENDS
BETTER IN THE MID RANGE PERIOD OF THE FORECAST. THUS CONFIDENCE
IS LOW IN WHEN AND WHERE TO PLACE HIGHEST CHANCES FOR RAIN
THURSDAY NIGHT THROUGH SUNDAY.
IT APPEARS THERE IS A BETTER CHANCE OF SHOWERS AND STORMS AT TIMES
SUNDAY NIGHT THROUGH TUESDAY NIGHT DEPENDING ON WHERE FRONTAL
BOUNDARY ACTUALLY SETS UP. COULD BE A FEW ROUNDS OF SHOWERS AND
STORMS WITH LOCALLY HEAVY RAIN...ASSUMING FIRST ROUND OR TWO OF
SHOWERS AND STORMS DOES NOT PUSH THE BOUNDARY FURTHER SOUTH.
PLENTY OF TIME TO WATCH THIS UNFOLD.
PREVIOUS SHIFT LOWERED MAXIMUM TEMPERATURES ON MONDAY AND THIS
STILL SEEMS REASONABLE. MAY NEED TO COOL IT DOWN EVEN A FEW MORE
DEGREES DUE TO CLOUD COVER AND EXPECTED RAIN FROM AN APPROACHING
WARM FRONT. HIGHS ON TUESDAY AND WEDNESDAY WILL BE DETERMINED BY
HOW MUCH SUN/LACK OF RAIN THAT OCCURS DURING THE DAY AND WHERE
WARM FRONT SETS UP.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1232 PM CDT WED SEP 4 2013
CDFNT TO CONT DROPPING SOUTH INTO SRN WI THIS
AFTERNOON AND INTO NRN IL TNGT. MAIN FCST ISSUE FOR AVIATION
PURPOSES WL BE THE NARROW AREA OF LOW CLOUDS LOCATED BEHIND THE
FNT. VSBL SATL IMAGERY SHOWED THIS CLOUD BAND THINNING OUT AS
DAYTIME MIXING TAKING PLACE. HOWEVER...AS COOLING OCCURS TNGT...
SUBSIDENCE INVERSION WL SHARPEN AND ALLOW FOR A STRATUS FIELD TO
DEVELOP. UNKNOWN QUESTION IS EXACTLY WHERE THESE CLOUDS WOULD
REFORM AS BASES WOULD BE AT LEAST MVFR IF NOT IFR AT SUNRISE.
BEST GUESS RIGHT NOW WOULD BE OVER THE SRN THIRD OF WI IMMEDIATELY
BEHIND THE FRONT. BELIEVE THAT MOST OF NE WI WL REMAIN VFR FOR
TNGT AND THU AS AN AREA OF HI PRES BUILDS INTO THE REGION.
&&
.MARINE...
ISSUED AT 339 AM CDT WED SEP 4 2013
W/SW WINDS EARLY TDA WL SHIFT TO THE NNE AS A SHARP COLD FRONT
SURGES SWD DOWN LAKE MICHIGAN AND THE BAY OF GREEN BAY. GUSTS ABV
25 KTS ARE LIKELY WITH THE FROPA AND FOR A COUPLE HRS AFTERWARD...
THEN WINDS SHOULD BEGIN TO SETTLE BACK DOWN. DURATION PROBABLY
WON/T BE SUFFICIENT TO DRIVE WAVES ABV 4 FT...THOUGH IT COULD GET
VERY CHOPPY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS.......SKOWRONSKI
SHORT TERM.....SKOWRONSKI
LONG TERM......ECKBERG
AVIATION.......AK
MARINE.........SKOWRONSKI