Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/03/13

AREA FORECAST DISCUSSION...CORRECTED

NWS PHOENIX AZ

 310 PM MST SUN SEP 1 2013

CORRECTED TYPO

.SYNOPSIS...
A DECLINE IN MONSOON MOISTURE WILL LEAD TO LOWER HUMIDITY AND
SLIGHTLY WARMER TEMPERATURES THAN WHAT HAS BEEN EXPERIENCED IN
RECENT DAYS. THERE WILL BE ENOUGH LINGERING MOISTURE AND WEATHER
DISTURBANCES TO KEEP AT LEAST A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE REGION THROUGH WEDNESDAY. ANTICIPATE A SLOW
EASTWARD RETREAT OF STORM CHANCES THE REST OF THE WEEK.

&&

.DISCUSSION...
REST OF TODAY THROUGH MONDAY...
WITH LESS MORNING CLOUDINESS AND SOMEWHAT LOWER SURFACE DEW
POINTS...24 HOUR TEMP TRENDS EARLY THIS AFTERNOON ARE RUNNING AT
LEAST A FEW DEGREES WARMER OVER SOUTH CENTRAL ARIZONA...LITTLE
CHANGE FURTHER WEST WHERE THERE WAS MORE STORM ACTIVITY LAST NIGHT.
SATELLITE AND RADAR IMAGERY AS OF 21Z SHOWS MEAGER STORM DEVELOPMENT
OVER EASTERN ARIZONA WITH ONLY ACTIVITY IN SANTA CRUZ COUNTY. THE
NORTHWEST QUARTER OF ARIZONA HAS HAD MOST OF THE STORMS SO FAR. IN
OUR FORECAST AREA...LA PAZ COUNTY HAS HAD A STRAY THUNDERSTORM SO
FAR. CUMULUS DEVELOPMENT OVER ZONE 24 INDICATES THAT THERE IS STILL
SOME MOISTURE TO WORK WITH. GPS IPW DATA TRENDS ARE A MIXED BAG WITH
SOME STATIONS SHOWING SOME ADDITIONAL DRYING SINCE THIS MORNING AND
SOME OTHERS WITH SOME REVERSAL OF THE DRYING TREND. BUT
OVERALL...NOT A LOT OF CHANGE FROM THE MORNING. HRRR MODEL CONTINUES
TO SHOW ONLY ISOLATED STORMS OVER SOUTH-CENTRAL ARIZONA THROUGH THIS
EVENING...MAINLY OVER ZONE 24...WITH BETTER COVERAGE FURTHER
WEST...MAINLY LA PAZ AND EASTERN RIVERSIDE COUNTIES. LATEST RUC/RAP
SHOWS A SIMILAR PATTERN BUT IS NOT AS GENEROUS OVER LA PAZ AND
EASTERN RIVERSIDE. THE NMM6KM AND LOCAL WRF ARE EVEN LESS GENEROUS
WITH STORM ACTIVITY. HOWEVER...THE AFTERNOON IS STILL YOUNG AND THE
INFLUENCE OF STORMS OVER NORTHERN SONORA REMAINS TO BE SEEN. NAM
APPEARS TO HAVE HAD A BETTER HANDLE ON THE MOISTURE TRENDS FOR TODAY
THAN THE GFS AS DEW POINTS HAVENT DROPPED AS MUCH. GFS HAD ALSO
UNDERINITIALIZED THE LOWER LEVEL MOISTURE OVER PORTIONS OF SOUTHWEST
ARIZONA AND SOUTHEAST CALIFORNIA. MADE SOME MINOR UPWARD TWEAKS TO
THE POPS FOR THIS EVENING DUE TO LINGERING MOISTURE AVAILABILITY AND
MORE UNSTABLE BOUNDARY LAYERS. ANTICIPATE SOME ADDITIONAL MOISTURE
DECLINE TOMORROW AND THUS SOMEWHAT LOWER POPS...BUT NOT ENOUGH TO
DROP THEM ALTOGETHER.

TUESDAY...
TROPICAL STORM KIKO OFF THE SOUTHERN BAJA COAST WILL NOT
BE SENDING A BIG SLUG OF TROPICAL MOISTURE INTO OUR FORECAST AREA
LIKE JULIETTE DID. HOWEVER...THERE IS AN INVERTED TROUGH/SHORT WAVE
ADVERTISED TO MOVE ACROSS NORTHERN MEXICO AND INTO SOUTHEAST ARIZONA
TUESDAY NIGHT. THIS WILL LEAD TO SOME UPPER LEVEL DIVERGENCE WHICH
WILL BE MORE CONDUCIVE TO STORM DEVELOPMENT. HOWEVER...THE GFS
DOESNT DEPICT A SUBSTANTIAL INCREASE IN MOISTURE WITH IT. IT ALSO IS
UNCHARACTERISTICALLY MODEST WITH THE DIVERGENCE FIELDS. ECMWF AND
NAM ARE A BIT MORE GENEROUS WITH MOISTURE AVAILABILITY.
MEANWHILE...THE REMNANT ATMOSPHERIC WAVE ASSOCIATED WITH KIKO MAY
ALSO BE A PLAYER...MORE SO FOR SOUTHEAST CALIFORNIA. GFS SHOWS IT
MOVING NORTHWARD ACROSS SOUTHERN CALIFORNIA ON TUESDAY GETTING
ABSORBED INTO THE MUCH LARGER WEST COAST TROUGH. THERE IS ALSO A
JETLET ASSOCIATED WITH THE WAVE WHICH LEADS TO SOME SPEED DIVERGENCE
WHICH MIGHT BE A SUBTLE DIFFERENCE MAKER. MADE SOME MODEST UPWARD
ADJUSTMENTS BUT INHERENT UNCERTAINTY ABOUT THESE FEATURES AND
MOISTURE AVAILABILITY MAKES HIGH POPS UNWARRANTED.

WEDNESDAY THROUGH SUNDAY...
MODELS ARE FORECASTING A NUMBER OF HARD TO TIME UPPER LEVEL
PERTURBATIONS MOVING INTO AZ FROM NORTHWEST MEXICO. THEREFORE A
SLIGHT CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE
WARRANTED.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
12Z MODELS SUGGESTING CONVECTION SHOULD REMAIN CONFINED TO THE
HIGHER TERRAIN SURROUNDING THE PHOENIX METRO AS SLIGHTLY DRIER AIR
MOVES INTO THE REGION. STORMS WILL BE ISOLATED IN NATURE BUT I DO
NOT ANTICIPATE ANYTHING DIRECTLY AFFECTING THE TERMINALS ASIDE FROM
DEBRIS CLOUDS. WINDS SHOULD FAVOR TYPICAL DIURNAL PATTERNS.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND
KBLH...
CLOUDS ARE CLEARING OUT AND HUMIDITIES REMAIN HIGH AT BOTH TAF
SITES...BUT MODELS SUGGESTING CONVECTION SHOULD REMAIN CONFINED TO
THE HIGHER TERRAIN AND STAY MOSTLY OUT OF THE LOWER DESERTS. I WILL
INCLUDE SOME DEBRIS CLOUDS IN THE TAFS LATER THIS AFTERNOON AND
EVENING BUT OTHERWISE NEITHER SITES SHOULD BE DIRECTLY IMPACTED
TODAY. WINDS WILL FAVOR THE USUAL DIURNAL TRENDS.

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. 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/VASQUEZ
AVIATION...LEINS
FIRE WEATHER...LEINS










SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED

NWS LOS ANGELES/OXNARD CA

 440 PM PDT MON SEP 2 2013

...UPDATED AVIATION DISCUSSION...

.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 LITTLE 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...02/2335Z.
AN AREA OF SUBTROPICAL MOISTURE IS MOVING INTO REGION LATE THIS AFTERNOON
INTO TONIGHT. ISOLATED STORMS ARE OCCURRING ACROSS THE ANTELOPE VALLEY
AS OF 430 PM...WHICH COULD IMPACT AREAS NEAR KPMD AND KWJF FOR NEXT
COUPLE OF HOURS. MEANWHILE...THERE IS A 20 PERCENT CHANCE OF SHOWERS OR
THUNDERSTORMS JUST ABOUT ANYWHERE TONIGHT AS MID LEVEL MOISTURE AND
INSTABILITY INCREASE FROM MOISTURE STREAMING UP FROM THE SOUTH. THIS
SURGE OF MID LEVEL MOISTURE IS EXPECTED TO DISRUPT THE NORMAL MARINE LAYER
CLOUDS TONIGHT...WITH ONLY A SLIGHT CHANCE OF CIGS RETURNING TO ANY COASTAL
TAF LOCATIONS.

KLAX...SURGE OF MID LEVEL MOISTURE STREAMING FROM THE SOUTH WILL BRING
A 20 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS TO KLAX TONIGHT INTO
TUESDAY MORNING. THIS MID LEVEL MOISTURE WILL DISRUPT THE LOW LEVEL MARINE
LAYER CLOUDS...THEREBY ONLY A 20 PERCENT CHANCE OF AN IFR CEILING
OVERNIGHT INTO TUESDAY MORNING.

KBUR...SURGE OF MID LEVEL MOISTURE STREAMING FROM THE SOUTH WILL
BRING A 20 PERCENT CHANCE OF SHOWERS AND THUNDERSTORMS TO KBUR
TONIGHT INTO TUESDAY MORNING.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

$$

PUBLIC...MW
AVIATION...GOMBERG
SYNOPSIS...BARTLING

WWW.WEATHER.GOV/LOSANGELES









AREA FORECAST DISCUSSION

NWS DENVER/BOULDER CO

 809 PM MDT MON SEP 2 2013

.UPDATE...ISOLATED SHOWERS AND THUNDERSTORMS OVER THE HIGHER
TERRAIN WILL CONTINUE TO DIMINISH AND COME TO AN END BY MIDNIGHT.
THE 00Z SOUNDING FROM KDEN SHOWED WARM AIR ALOFT AND A CAP AROUND
400 MB. WITH THE LOSS OF DAYTIME HEATING...ALL CONVECTION SHOULD
END SOON. THE HRRR SHOWS A FEW STORMS ALONG THE WYOMING
BORDER IN THE NEXT 2 HOURS...BUT NO OTHER MODELS SHOW THIS.
LOOKING AT SATELLITE IT APPEARS THE STORMS WILL STAY NORTH OF
INTERSTATE 80. IT WILL BE MILD NIGHT FOR THIS TIME OF YEAR WITH
LOWS IN THE UPPER 50S TO LOWER 60S.

&&

.AVIATION...SOUTHERLY WINDS WILL PREVAIL THROUGH THE NIGHT AT KAPA
AND KDEN. LIGHT WINDS WILL PREVAIL ON TUESDAY. SCATTERED MID AND
HIGH CLOUDS WILL MOVE ACROSS THE AREA TONIGHT AND TUESDAY. CHANCES
FOR STORMS TUESDAY AFTERNOON WILL BE VERY LOW AND NOT WORTH
MENTIONING IN THE TAFS.

&&

.PREV DISCUSSION... /ISSUED 231 PM MDT MON SEP 2 2013/

SHORT TERM...ISOLATED T-STORMS NOW FORMING IN THE HIGH COUNTRY
PRINCIPALLY ALONG THE EAST SIDE OF THE CONTINENTAL DIVIDE AND
OVER THE HIGHER TERRAIN SURROUNDING SOUTH PARK. MARGINALLY
UNSTABLE HIGH COUNTRY AIRMASS HAS GROWN INCREASINGLY MOIST IN THE
PAST SEVERAL HOURS. EAST OF THE MTNS...ATMOSPHERE JUST AS MOIST
WITH THE PRECIPITABLE WATER VALUE AT DENVER NOW OVER AN
INCH...1.07 INCHES TO BE EXACT. HOWEVER...AIRCRAFT AND RAP
SOUNDINGS REVEAL A STRONG SUBSIDENCE INVERSION AROUND 500MBS WITH
VERY LITTLE SFC BASED CAPE UP ALONG THE FRONT RANGE. HOWEVER
FARTHER OUT ON THE PLAINS...RAP AND WRF MODELS INDICATE A RIBBON
OF 500-1000 J/KG BNDRY LAYER CAPE CENTERED ALONG A WIND SHEAR AXIS
EXTENDING FROM SRN LINCOLN COUNTY TO SEDGWICK COUNTY. EAST OF THIS
AXIS...SFC WINDS SELY 15-25 KTS WITH MID/UPR 50S DEWPTS. WRF
INDICATES A SMALL AREA OF CONVECTION/T-STORMS FORMING ALONG THIS
AXIS OVER ERN PORTIONS OF ADAMS/ARAPAHOE COUNTIES AND SRN MORGAN
COUNTY EARLY THIS EVENING. SHOULD THEY MANAGE TO FORM WITH THE
STRONG CAP...THERE IS A SLIGHT CHANCE THAT ONE OR TWO OF THEM
COULD SEVERE WITH STRONG OUTFLOW WINDS MAIN THREAT. OTHERWISE...
NOT EXPECTING ANY T-STORMS EAST OF THE MTNS TONIGHT...EXCEPT
PERHAPS A STRAY HIGH BASED...MOSTLY DRY T-STORM DRIFTING OFF THE
FOOTHILLS OVER SRN PORTIONS OF THE I-25 URBAN CORRIDOR AND OVER
WRN PORTIONS OF THE PALMER DIVIDE BTWN MON/21Z AND TUE/02Z. STORMS
SHOULD END BY MID-EVENING WITH CLEARING OVERNIGHT.

ON TUESDAY...HOT AIRMASS WITH A STRONG UPPER HIGH SHIFTS EAST OVER
THE STATE. MODELS SHOW A 595 DECAMETER 500MB HIGH CENTERED OVER
SOUTH CENTRAL COLORADO BY MIDDAY. MODELS CONTINUE TO INDICATE A
DECENT AMOUNT OF MOISTURE CIRCULATING AROUND THE HIGH...BUT WITH
THE WARMING ALOFT...SHOULD SEE FEWER STORMS IN THE HIGH COUNTRY
AND VIRTUALLY NO STORMS ON THE PLAINS TUESDAY. FCST HIGHS TOMORROW
WILL RANGE FROM TO THE VERY WARM 70S-MID 80S ACROSS THE HIGH
COUNTRY...TO THE UNSEASONABLY WARM LOWER TO MID 90S ON THE PLAINS.
AVERAGE HIGH AT DENVER FOR THE 3RD IS 84F.

LONG TERM...LITTLE IF ANY ADJUSTMENT PLANNED. THE UPPER LEVEL
RIDGE WILL REMAIN CENTERED OVER COLORADO THROUGH FRIDAY. IT WILL
THEN SHIFT TO THE SOUTH AND EAST AS AN UPPER LEVEL TROUGH MOVES
INTO THE NORTHERN ROCKIES. THERE WILL BE ENOUGH MOISTURE TRAPPED
UNDER THE RIDGE FOR A CHC OF AFTN AND EVENING THUNDERSTORMS OVER
THE MOUNTAINS...WITH A LESSER CHANCE OVER THE NORTHEAST PLAINS. BY
MONDAY...THE FLOW BECOMES MORE SOUTHWESTERLY AND THE SUBSIDENCE
ASSOCIATED WITH THE RIDGE WILL BE WEAKER. THIS SHOULD RESULT IN A
BETTER CHANCE OF TSTMS OVER THE CWFA. A FRONT IS PROGGED TO MOVE
ACROSS NORTHEAST COLORADO LATE MONDAY/MONDAY NIGHT WITH COOLER
TEMPERATURES POSSIBLE BY EARLY NEXT WEEK.

AVIATION...VFR CONDITIONS LIKELY FOR THE NEXT 24 HOURS. THERE IS
STILL A SLIGHT CHANCE FOR HIGH BASE...MOSTLY DRY T-STORMS IN THE
DENVER METRO AREA TODAY...NAMELY FOR AREAS UP AGAINST THE
FOOTHILLS AND OVER SOUTHERN SECTIONS OF THE DENVER METRO AREA
AFTER 22Z TODAY. BJC AND APA COULD SEE GUSTY OUTFLOW WINDS TO
AROUND 35KTS ALONG WITH SOME CG LIGHTNING WITH THESE WEAK...
POORLY ORGANIZED STORMS. EAST/SOUTHEAST SFC WINDS OF 8-15 KTS THIS
AFTERNOON FORECAST TO GO DRAINAGE WITH CLEARING SKIES AROUND
SUNSET. ON TUESDAY...DRIER...WARMER AND MORE STABLE CONDITIONS
WILL NEGATE ANY CHANCE OF T-STORMS IN THE DENVER AREA. LIGHT
DRAINAGE WINDS IN THE MORNING WILL BECOME LIGHT EAST- SOUTHEAST IN
THE AFTERNOON

HYDROLOGY...INCREASING PRECIPITABLE WATER LEVELS TOGETHER WITH
STRONG SOLAR HEATING WILL CONTINUE TO PRODUCE ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS IN THE HIGH COUNTRY FOR THE
REMAINDER OF THIS AFTERNOON. MOST OF THIS STORM ACTIVITY WILL
CONCENTRATE OVER THE HIGHER FRONT RANGE FOOTHILLS...AND HIGHER
TERRAIN CIRCLING SOUTH PARK. A FEW OF THESE STORMS MAY PRODUCE
HEAVY RAINFALL AND PERHAPS SOME SMALL HAIL. RAINFALL AMOUNTS WILL
GENERALLY RANGE FROM 0.10 TO 0.40 INCH...WITH LOCALLY UP TO 1.25
INCHES WITH THE STRONGER STORMS SOUTH OF INTERSTATE 70. THERE IS
ALSO A SLIGHT CHANCE THAT A STRONG STORM CAPABLE OF BRIEF HEAVY
RAINFALL AND STRONG GUSTY WINDS WILL DRIFT EAST OVER WESTERN
SECTIONS OF THE PALMER DIVIDE IN THE NEXT 2-3 HOURS. THE CHANCE OF
THE HEAVY RAINFALL ON THE FRONT RANGE BURN SCARS APPEARS LOW AT
THIS TIME. TOMORROW...LOOKS DRIER..WARMER AND MORE STABLE. SO
THERE WILL BE FEWER STORMS WITH LESS RAINFALL.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BAKER
LONG TERM....COOPER
AVIATION...MEIER




AREA FORECAST DISCUSSION

NWS PUEBLO CO

 230 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 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 226 PM MDT SUN SEP 1 2013

IN GENERAL...VFR CONDITIONS ARE EXPECTED AT KCOS...KPUB AND KALS.
HOWEVER...SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN THE EVENING
HOURS AT THE TERMINAL SITES AND COULD BRIEFLY BRING REDUCED
VSBYS/CIGS.  THERE IS ALSO THE POTENTIAL FOR STRATUS DEVELOPMENT NR
KCOS LATE TONIGHT.  SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN
MONDAY AFTERNOON...WITH KCOS AND KALS HAVING A BETTER CHANCE THAN
KPUB.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...28
LONG TERM...STARK
AVIATION...28







AREA FORECAST DISCUSSION

NWS GRAND JUNCTION CO

 1112 AM MDT SUN SEP 1 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 431 AM MDT SUN SEP 1 2013

SUBTLE CHANGES IN THE RIDGE POSITIONING LEADS TO A WESTWARD SHIFT
OF THE DEEP MONSOONAL MOISTURE PLUME...APPEARS FARTHER WEST THAN
WHAT EARLIER MODELS MAY HAVE SHOWN. THE END RESULT IS FOR LESS
CONVECTIVE POTENTIAL ACROSS THE DESERT VALLEYS (FROM SE UTAH INTO
THE GRAND VALLEY) THIS AFTERNOON.

OBJECTIVE ANALYSIS PLACES SUBTROPICAL WAVE WITH DEEP MOIST LAYER
ACROSS SRN NEVADA/SWRN UTAH/NWRN ARIZONA WITH A VORTICITY LOBE
THAT EXTENDS INTO ERN UTAH. RADAR INDICATING SOME SPOTTY SHOWERS
ASSOCIATED WITH THIS ERN UTAH VORT LOBE. RAP AND HRRR MODEL SHOWS
THIS FEATURE LIFTING NORTH OVER THE BOOKCLIFFS BY LATE MORNING...
ENHANCING CONVECTION OVER THE BOOKCLIFFS THAT EXTENDS INTO WRN
COLORADO AS FAR EAST AS INDEPENDENCE PASS.

RAP/NAM/GFS MODELS SHOW RIDGE AXIS POSITIONED JUST WEST OF THE
COLORADO SPINE AND AMPLIFIES AS THE DAY PROGRESSES. DRIER AIR THAT
HAS ADVECTED INTO ERN ARIZONA WILL BE DRAWN NORTHWARD INTO SERN
UTAH THIS MORNING...REACHING NW COLORADO LATE THIS AFTERNOON. THIS
RIBBON OF MID LEVEL DRIER AIR LIMITS CONVECTIVE POTENTIAL ACROSS
THE WRN HALF OF OUR FORECAST AREA. WITH WATER VAPOR LOOP CONFIRMING
THIS TREND...CANNOT JUSTIFY THE CONTINUATION OF THE FLASH FLOOD
WATCH FOR SOUTHEAST UTAH AS DEEP CONVECTIVE TOWERS WILL NOT
SURVIVE THE PROMINENT DRY AIR INTRUSION.

DIFFERENT ENVIRONMENT OVER THE COLORADO CENTRAL MOUNTAINS WITH
MOISTURE IN PLACE WITH SOME SHEAR IN THE 15-20 KT RANGE...CONVECTION
THAT FIRES OVER THE BOOKCLIFFS/ROAN PLATEAU AND FLAT TOP MOUNTAINS
WILL TRACK ESE ACROSS EAGLE AND PITKIN COUNTY AND THIS AREA GETS
THE HIGHEST POP VALUES FOR THIS AFTERNOON.

MODELS REMAIN CONSISTENT LEAVING THE SUB TROPICAL HIGH CIRCULATION
TO SPIN OVER CENTRAL NEW MEXICO THROUGH THE NEXT 24 TO 36 HOURS.
THIS IS WHERE 00Z HAND ANALYSIS HAS IT LOCATED AS WELL...BUT THE
ARIZONA WAVE IS NOT QUITE AS DISTINCT AS 24 HOURS AGO AND A BIT
FARTHER WEST. PWAT LOOKS TO PEAK THROUGH THE DAY ACROSS THE WESTERN
CWA THEN MODELS SHOW A DECLINING TREND THROUGH THE FIRST OF THE
WEEK...BUT STILL ABOVE NORMAL. WITH THE ARIZONA WAVE LIFTING A BIT
FARTHER WEST...MOISTURE LOOKS TO GET SPLIT APART BY THIS EVENING.
SOME LIFTING WITH THE WAVE AND THE REST WRAPPING TOWARD THE
CIRCULATION OVER NEW MEXICO...LEAVING A PSEUDO-DRY SLOT FROM THE 4
CORNERS TO THE NORTHERN MOUNTAINS GOING INTO LABOR DAY. WEAK ASCENT
ASSOCIATED WITH THE WAVE TO THE WEST PUSHES ACROSS NORTHERN UTAH AND
NORTHWEST COLORADO LATE TONIGHT INTO MONDAY MORNING AND MAY HELP
FOCUS CONVECTION DURING THE TIME. MOISTURE ALSO POOLS NEAR THE
SOUTHERN MOUNTAINS SO THESE TWO AREAS SHOULD HAVE THE BEST CHANCES
FOR PRECIPITATION WHILE IN BETWEEN CONFIDENCE IS LOWER. UPPER FLOW
NOT IMPRESSIVE BUT STORM MOTION TO THE NORTH SHOULD BE MORE APPARENT
THAN THE PAST FEW DAYS AND MAY HELP ALLEVIATE SOME OF THE FLOODING
POTENTIAL. LOCALLY HEAVY RAIN STILL POSSIBLE WITH WARM CLOUD RAIN
PROCESSES STILL IN PLACE. EXPECT A BIT MORE SUNSHINE ON MONDAY SO
PUSHED TEMPS UP A FEW DEGREES MANY AREAS CLOSER TO THE MAV GUIDANCE.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 431 AM MDT SUN SEP 1 2013

SHOULD BE A BIT OF DOWNTURN TO THE CONVECTION OVER THE NORTHWEST 2/3
OF THE CWA AS THE UPPER HIGH WOBBLES TO THE NORTHWEST. THIS WILL
LEAVE THE 4 CORNERS TO THE CENTRAL MOUNTAINS UNDER THE CIRCULATION
WHERE RESIDUAL MOISTURE WILL BE POOLING. THEREFORE REFOCUSED THE
HIGH POPS TO OUR SOUTHERN CWA TAPERING OFF TO THE NORTH. HIGH NOT
CHANGING MUCH AND SHOULD REMAIN ABOVE NORMAL MOST AREAS.

TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL BE ANCHORED OVER THE
COLORADO ROCKIES. MONSOONAL MOISTURE PLUME WILL BE WEST OF OUR
FORECAST AREA. SOME MONSOONAL MOISTURE WILL BE TRAPPED BENEATH THE
HIGH CORE TO ALLOW FOR DAILY SHOWERS AND THUNDERSTORMS. WITH SHEAR
ESSENTIALLY NON EXISTENT...MOST STORMS WILL STAY PUT OVER THE
MOUNTAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1110 AM MDT SUN SEP 1 2013

SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON...ESPECIALLY TOWARD THE CONTINENTAL DIVIDE WHERE
MOUNTAIN PEAKS AND RIDGE TOPS WILL BE OBSCURED FROM RAIN SHAFTS
AND LOW CIGS. FARTHER WEST OVER THE LOWER DESERT VALLEYS...AREAL
COVERAGE OF -SHRA/-TSRA WILL BE ISOLATED. SHOWERS AND STORMS
DIMINISH AFTER 02Z.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.

UT...NONE.

&&

$$

SHORT TERM...PF/15
LONG TERM...15/PF
AVIATION...JDC







AREA FORECAST DISCUSSION

NWS GRAND JUNCTION CO

 431 AM MDT SUN SEP 1 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 431 AM MDT SUN SEP 1 2013

SUBTLE CHANGES IN THE RIDGE POSITIONING LEADS TO A WESTWARD SHIFT
OF THE DEEP MONSOONAL MOISTURE PLUME...APPEARS FARTHER WEST THAN
WHAT EARLIER MODELS MAY HAVE SHOWN. THE END RESULT IS FOR LESS
CONVECTIVE POTENTIAL ACROSS THE DESERT VALLEYS (FROM SE UTAH INTO
THE GRAND VALLEY) THIS AFTERNOON.

OBJECTIVE ANALYSIS PLACES SUBTROPICAL WAVE WITH DEEP MOIST LAYER
ACROSS SRN NEVADA/SWRN UTAH/NWRN ARIZONA WITH A VORTICITY LOBE
THAT EXTENDS INTO ERN UTAH. RADAR INDICATING SOME SPOTTY SHOWERS
ASSOCIATED WITH THIS ERN UTAH VORT LOBE. RAP AND HRRR MODEL SHOWS
THIS FEATURE LIFTING NORTH OVER THE BOOKCLIFFS BY LATE MORNING...
ENHANCING CONVECTION OVER THE BOOKCLIFFS THAT EXTENDS INTO WRN
COLORADO AS FAR EAST AS INDEPENDENCE PASS.

RAP/NAM/GFS MODELS SHOW RIDGE AXIS POSITIONED JUST WEST OF THE
COLORADO SPINE AND AMPLIFIES AS THE DAY PROGRESSES. DRIER AIR THAT
HAS ADVECTED INTO ERN ARIZONA WILL BE DRAWN NORTHWARD INTO SERN
UTAH THIS MORNING...REACHING NW COLORADO LATE THIS AFTERNOON. THIS
RIBBON OF MID LEVEL DRIER AIR LIMITS CONVECTIVE POTENTIAL ACROSS
THE WRN HALF OF OUR FORECAST AREA. WITH WATER VAPOR LOOP CONFIRMING
THIS TREND...CANNOT JUSTIFY THE CONTINUATION OF THE FLASH FLOOD
WATCH FOR SOUTHEAST UTAH AS DEEP CONVECTIVE TOWERS WILL NOT
SURVIVE THE PROMINENT DRY AIR INTRUSION.

DIFFERENT ENVIRONMENT OVER THE COLORADO CENTRAL MOUNTAINS WITH
MOISTURE IN PLACE WITH SOME SHEAR IN THE 15-20 KT RANGE...CONVECTION
THAT FIRES OVER THE BOOKCLIFFS/ROAN PLATEAU AND FLAT TOP MOUNTAINS
WILL TRACK ESE ACROSS EAGLE AND PITKIN COUNTY AND THIS AREA GETS
THE HIGHEST POP VALUES FOR THIS AFTERNOON.

MODELS REMAIN CONSISTENT LEAVING THE SUB TROPICAL HIGH CIRCULATION
TO SPIN OVER CENTRAL NEW MEXICO THROUGH THE NEXT 24 TO 36 HOURS.
THIS IS WHERE 00Z HAND ANALYSIS HAS IT LOCATED AS WELL...BUT THE
ARIZONA WAVE IS NOT QUITE AS DISTINCT AS 24 HOURS AGO AND A BIT
FARTHER WEST. PWAT LOOKS TO PEAK THROUGH THE DAY ACROSS THE WESTERN
CWA THEN MODELS SHOW A DECLINING TREND THROUGH THE FIRST OF THE
WEEK...BUT STILL ABOVE NORMAL. WITH THE ARIZONA WAVE LIFTING A BIT
FARTHER WEST...MOISTURE LOOKS TO GET SPLIT APART BY THIS EVENING.
SOME LIFTING WITH THE WAVE AND THE REST WRAPPING TOWARD THE
CIRCULATION OVER NEW MEXICO...LEAVING A PSEUDO-DRY SLOT FROM THE 4
CORNERS TO THE NORTHERN MOUNTAINS GOING INTO LABOR DAY. WEAK ASCENT
ASSOCIATED WITH THE WAVE TO THE WEST PUSHES ACROSS NORTHERN UTAH AND
NORTHWEST COLORADO LATE TONIGHT INTO MONDAY MORNING AND MAY HELP
FOCUS CONVECTION DURING THE TIME. MOISTURE ALSO POOLS NEAR THE
SOUTHERN MOUNTAINS SO THESE TWO AREAS SHOULD HAVE THE BEST CHANCES
FOR PRECIPITATION WHILE IN BETWEEN CONFIDENCE IS LOWER. UPPER FLOW
NOT IMPRESSIVE BUT STORM MOTION TO THE NORTH SHOULD BE MORE APPARENT
THAN THE PAST FEW DAYS AND MAY HELP ALLEVIATE SOME OF THE FLOODING
POTENTIAL. LOCALLY HEAVY RAIN STILL POSSIBLE WITH WARM CLOUD RAIN
PROCESSES STILL IN PLACE. EXPECT A BIT MORE SUNSHINE ON MONDAY SO
PUSHED TEMPS UP A FEW DEGREES MANY AREAS CLOSER TO THE MAV GUIDANCE.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 431 AM MDT SUN SEP 1 2013

SHOULD BE A BIT OF DOWNTURN TO THE CONVECTION OVER THE NORTHWEST 2/3
OF THE CWA AS THE UPPER HIGH WOBBLES TO THE NORTHWEST. THIS WILL
LEAVE THE 4 CORNERS TO THE CENTRAL MOUNTAINS UNDER THE CIRCULATION
WHERE RESIDUAL MOISTURE WILL BE POOLING. THEREFORE REFOCUSED THE
HIGH POPS TO OUR SOUTHERN CWA TAPERING OFF TO THE NORTH. HIGH NOT
CHANGING MUCH AND SHOULD REMAIN ABOVE NORMAL MOST AREAS.

TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL BE ANCHORED OVER THE
COLORADO ROCKIES. MONSOONAL MOISTURE PLUME WILL BE WEST OF OUR
FORECAST AREA. SOME MONSOONAL MOISTURE WILL BE TRAPPED BENEATH THE
HIGH CORE TO ALLOW FOR DAILY SHOWERS AND THUNDERSTORMS. WITH SHEAR
ESSENTIALLY NON EXISTENT...MOST STORMS WILL STAY PUT OVER THE
MOUNTAINS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 431 AM MDT SUN SEP 1 2013

AFTER 18Z...SHOWERS AND THUNDERSTORMS WILL QUICKLY FORM OVER THE
MOUNTAIN AREAS...ESPECIALLY TOWARD THE CONTINENTAL DIVIDE WHERE
MOUNTAIN PEAKS AND RIDGE TOPS WILL BE OBSCURED FROM RAIN SHAFTS
AND LOW CIGS. FARTHER WEST OVER THE LOWER DESERT VALLEYS...AREAL
COVERAGE OF -SHRA/-TSRA WILL BE ISOLATED. SHOWERS AND STORMS
DIMINISH AFTER 02Z.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.

UT...NONE.

&&

$$

SHORT TERM...PF/15
LONG TERM...15/PF
AVIATION...PF







AREA FORECAST DISCUSSION

NWS ALBANY NY

 155 PM EDT SUN SEP 1 2013

.SYNOPSIS...
A PERSISTENT WARM AND HUMID AIR MASS FOR THE FIRST DAY
OF SEPTEMBER WILL REMAIN OVER THE REGION THROUGH LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 110 PM EDT...VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW A
GOOD DEAL OF CLOUDINESS AROUND THE REGION EARLY THIS AFTERNOON. A
DIFFUSE SFC FRONTAL BOUNDARY REMAINS SITUATED NEAR THE FAR
SOUTHEASTERN CORNER OF THE CWA. SHOWER AND THUNDERSTORM ACTIVITY
HAS INCREASED ACROSS MAINLY ULSTER...DUTCHESS AND LITCHFIELD
COUNTIES SO RAISED POPS TO LIKELY IN THESE AREA. SPC RAP ANALYSIS
SHOW A DECENT INSTABILITY GRADIENT ACROSS THE AREA WITH ONLY
AROUND 500 J/KG OF CAPE ACROSS THE ADIRONDACKS...WITH AROUND 2000
J/KG SOUTH AND EAST OF ALBANY. THE MOST UNSTABLE AREA COINCIDES
WITH WHERE THE SURFACE BOUNDARY IS...THUS THE HIGHER POPS. LOWERED
TO SLIGHT CHANCE FOR MUCH OF THE WESTERN/SOUTHERN ADIRONDACKS DUE
TO LACK OF FORCING.

THE DIFFUSE FRONTAL BOUNDARY WILL CREEP BACK NORTHWARD DURING THE
THE REST OF THE DAYLIGHT HOURS...WITH POP-UP SHOWERS AND
THUNDERSTORMS EXPECTED TO INCREASE IN COVERAGE ESPECIALLY SOUTH
AND EAST OF ALBANY. THE COVERAGE AREA SHOULD BE A LITTLE LESS
THAN YESTERDAY...WITH THE MOST ACTIVITY FOR SOUTHERN AREAS CLOSER
TO THE BOUNDARY. THE PWAT VALUE ON THE 12Z KALY SOUNDING WAS 1.52
INCHES...WHICH IS SLIGHTLY ABOVE NORMAL...SO ANY THUNDERSTORM WILL
BE CAPABLE OF PRODUCING HEAVY DOWNPOURS IN A SHORT PERIOD OF TIME.
ENHANCED WORDING IN THE GRIDS AND HWO PRODUCT WAS CONTINUED FOR
HEAVY RAINFALL WITH ANY CONVECTION TODAY FOR SOUTHEASTERN PARTS OF
THE AREA...WHICH WILL HAVE BETTER COVERAGE DUE TO BEING MORE
CLOSELY LOCATED TO THE SFC FRONTAL BOUNDARY.

THE SBCAPE VALUES FROM BOTH THE GFS AND NAM ARE A BIT LOWER TODAY
IN THE 500-1000 J/KG WITH POCKETS OF 1500-2000 J/KG SOUTH OF THE
CAPITAL DISTRICT WHERE THE SFC DEWPTS WILL BE IN THE U60S TO L70S.
THE PROJECTED VALUE FOR THIS AFTN BASED ON THE 12Z KALY SOUNDING
WAS AROUND 1085 J/KG. NOT ANTICIPATING ANY SEVERE WEATHER AGAIN
WITH WEAK MID LEVEL LAPSE RATES AND WEAK DEEP SHEAR PREVENTING ANY
DEEP WELL ORGANIZED CONVECTION.

H850 TEMPS IN THE +15C TO +17C RANGE WITH SOME SUNSHINE FOR A FEW
HOURS WILL ALLOW TEMPS TO GET IN THE M70S TO M80S ACROSS THE FCST
AREA. THE NRN ZONES MAY ACTUALLY HAVE MORE SUNSHINE TODAY...SINCE
THE WEAK BOUNDARY WILL BE ACROSS THE SOUTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...A STRONG UPPER LEVEL LOW WILL BE CHURNING EASTWARD FROM
THE UPPER GREAT LAKES REGION AND ONTARIO. THE LARGE SFC TROUGH OF
LOW PRESSURE WILL BE MOVING TOWARDS THE NORTHEAST. ONE SHORT-WAVE
ASSOCIATED WITH THE SYSTEM IN THE SOUTHWEST FLOW ALOFT WILL IMPACT
THE REGION SHORTLY BEFORE OR JUST AFTER MIDNIGHT WITH SHOWERS AND
EMBEDDED THUNDERSTORMS...OR EVEN A DEVELOPING STRATIFORM RAIN
SHIELD. THE QG LIFT STRENGTHENS BTWN 06Z-12Z DUE TO THE
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION AND WEAK THERMAL
ADVECTION. THE RAIN INTENSIFIES DUE TO A PLUME OF UPPER LEVEL
DIVERGENCE MOVING OVER ERN NY. POPS WERE KEPT IN THE LIKELY OR
LOW-CATEGORICAL RANGE. MIN TEMPS WILL BE OF THE WET BULB VARIETY
IN THE M60S TO NEAR 70F WITH SOME L60S OVER THE MTNS.

LABOR DAY...THE LEAD SHORT-WAVE CROSSES THE REGION IN THE
MORNING/EARLY PM. THE RAINFALL COULD INCREASE IN INTENSITY AGAIN IN
THE EARLY TO MID PM...AS PORTIONS OF ERN NY WILL BE NEAR THE RIGHT
ENTRANCE REGION OF A 60-70 KT H250 JET STREAK. ALSO...SOME BREAKS
IN THE CLOUDS COULD ALLOW FOR ENOUGH DESTABILIZATION FOR SOME
STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. THIS SET-UP IS STILL A
BIT NEBULOUS...BUT A STRONG COLD FRONT WILL BE APPROACHING IN THE
MID TO LATE PM. STRONG CONVERGENCE IS EXPECTED WITH THE BOUNDARY.
PLENTY OF LOW-LEVEL MOISTURE WILL BE IN PLACE WITH PWATS STILL A
COUPLE OF STD DEVS ABOVE NORMAL. SBCAPES VALUES MAY RANGE FROM
500-1500 J/KG WITH THE 0-6 KM BULK SHEAR VALUES RAMPING UP TO
25-35 KTS. THE SEE TEXT FROM SPC LOOKS FINE...BECAUSE THE SEVERE
POTENTIAL WILL BE CONDITIONAL TO THE AMOUNT OF SFC HEATING THAT
OCCURS...AND THE TIMING OF THESE IMPULSES ROTATING AROUND THE UPPER
LEVEL LOW. THE MID LEVEL LAPSE RATES STILL DON/T FALL TO 6.5 C/KM
OR LOWER UNTIL AFTER DARK. HEAVY RAINFALL LOOKS LIKE A GOOD BET
WITH A WIDESPREAD HALF AN INCH TO AN INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS TO 2 INCHES. WIDESPREAD FLASH FLOODING DOES NOT
LOOK LIKELY AT THIS TIME...BUT THE POSSIBILITY WILL CONTINUE TO BE
MONITORED.

OUR FORECAST REFLECTS MAX TEMPS CLOSER TO THE COOLER NAM MOS
VALUES FOR THE HOLIDAY WITH U70S TO L80S IN THE VALLEYS...AND
U60S TO M70S OVER THE HIGH PEAKS.

MON NIGHT...THE SHOWERS AND THUNDERSTORMS WILL END WITH THE
PASSAGE OF THE FIRST COLD FRONT. THE BETTER COLD ADVECTION DOES
NOT ARRIVE UNTIL AFTER DAY BREAK. LOWS WILL RANGE FROM THE MID AND
U50S OVER THE NW ZONES TO LOWER TO M60S OVER THE SE ZONES.

TUE-TUE NIGHT...MUCH COOLER AIR INVADES THE FCST AREA...AS THE
HUMIDITY BREAKS. THE UPPER LEVEL TROUGH AXIS...AND A SECONDARY
COLD FRONT MOVE THROUGH DURING THE DAY WITH ISOLD-SCT SHOWERS
POSSIBLE BASED ON THE NAM/GFS/ECMWF/CANADIAN GUIDANCE. H850 TEMPS
FALL TO AROUND +10C NEAR THE CAPITAL REGION. THE COLD POOL WILL
HELP FOCUS INSTABILITY SHOWERS. MAX TEMPS WILL BE IN THE MID 70S
TO L80S IN THE VALLEYS...WITH M60S TO M70S OVER THE MTNS. LOWS
WILL COOL OFF INTO THE 50S FOR MOST OF THE REGION TUE NIGHT...WITH
SOME U40S OVER THE MTNS.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE NORTHEAST WILL
REMAIN UNDER A LONGWAVE TROUGH FOR THE PERIOD.

WE ARE LOOKING FOR PLEASANT DAY WEDNESDAY AS HIGHER PRESSURE BUILDS
IN WITH SEASONABLY WARM TEMPERATURES. A COLD FRONT IS FORECAST TO
MOVE ACROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY USHERING IN A
MORE AUTUMN-LIKE AIRMASS AS CANADIAN HIGH PRESSURE BUILDS IN ITS
WAKE. AN INCREASE CLOUDS ALONG WITH ISOLATED SHOWERS SHOULD ACCOMPANY
THE BOUNDARY. TEMPERATURES THURSDAY AND FRIDAY SHOULD RUN ABOUT 5
DEGREES BELOW NORMAL.

TEMPERATURES ARE ANTICIPATED TO MODERATE BACK TO SEASONABLE LEVELS
FOR THE START OF THE WEEKEND AS THE SURFACE HIGH SHIFTS TO OUR
SOUTHEAST ALLOWING A SOUTH-SOUTHWEST FLOW TO DEVELOP.
HOWEVER...THERE ARE MODEL DIFFERENCES DEALING WITH THE TIMING AND
STRENGTH OF INDIVIDUALS SHORT WAVE ROTATING ABOUT AN UPPER LOW
OVER EASTERN CANADA. THIS WILL IMPACT THE TIMING OF FRONTAL
BOUNDARIES ACROSS THE REGION NEXT WEEKEND. AT THIS TIME...IT APPEARS
A WARM FRONT SHOULD MOVE INTO/THROUGH THE REGION ON SATURDAY AS A LOW
PASSES TO OUR NORTH.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A FRONTAL BOUNDARY IS SITUATED JUST TO THE SOUTH OF THE
REGION...ALLOWING FOR SOME SCT SHOWERS AND THUNDERSTORMS NEAR
KPOU. WITHIN ANY SHOWER OR TSTM...A BRIEF PERIOD OF IFR CONDITIONS
IS POSSIBLE. FURTHER NORTH...KALB/KPSF/KGFL LOOK QUIET FOR THE
NEXT FEW HOURS WITH VFR OR HIGH END MVFR CIGS...BUT THE THREAT
FOR SHOWERS/STORMS WILL RETURN TO THESE SITES FOR THE EVENING AS
THE FRONTAL BOUNDARY BEGINS TO LIFT BACK NORTHWARD. SFC WINDS LOOK
VERY LIGHT...GENERALLY 5 KTS OR LESS THROUGH THE EVENING.

TONIGHT INTO MONDAY MORNING...ADDITIONAL SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ACROSS THE ENTIRE REGION AS A SLOW MOVING COLD FRONT AND
ASSOCIATED UPPER TROUGH APPROACH THE AREA. THIS WILL ALLOW FOR
MVFR CONDITIONS AND POSSIBLE PERIODS OF IFR AS WELL WITHIN
SHOWERS...POSSIBLE THUNDERSTORMS AND LOW CLOUDS. WINDS WILL BE
NEARLY CALM OVERNIGHT...BECOMING SOUTHERLY ON MONDAY AT 5-10 KTS.
SOME IMPROVEMENT IN FLYING CONDITIONS MAY OCCUR TOWARDS MIDDAY
MONDAY...ESP FOR THE VALLEY TERMINALS.

OUTLOOK...
MON NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
TUE-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED THE NEXT SEVERAL DAYS. A HUMID
AIR MASS WITH SEVERAL CHANCES OF RAINFALL WILL BE POSSIBLE INTO
TUESDAY.

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

HIGH RH VALUES OF 55 TO 75 PERCENT WILL OCCUR THIS AFTERNOON. THE
RH VALUES WILL RECOVER CLOSE TO 100 PERCENT MONDAY MORNING...AND
REMAIN HIGH IN THE AFTERNOON AT 65 TO 85 PERCENT.

EXPECT WINDS FROM THE SOUTHEAST OR SOUTH AT 5 TO 15 MPH TODAY.
LIGHT AND VARIABLE WINDS WILL OCCUR TONIGHT. SOUTH OR SOUTHWEST WINDS
OF 5 TO 15 MPH ARE FORECAST FOR LABOR DAY.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED OR ISOLATED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR
WIDESPREAD RAINFALL WILL BE TONIGHT AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. SOME LOCATIONS COULD GET A QUICK FEW
INCHES OF RAINFALL IN 3 HOURS OR LESS...AS WHAT OCCURRED ON
SATURDAY AND THIS MORNING.

ISOLATED URBAN...SMALL STREAM...AND POOR DRAINAGE FLOODING WILL BE
POSSIBLE THE REMAINDER OF THE HOLIDAY WEEKEND. SOME SUBSTANTIAL WITHIN
BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE SHOWERS AND STORMS
OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS TIME FRAME.

HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW MOVING
THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING TODAY INTO LABOR
DAY. IF THE POTENTIAL FOR WIDESPREAD FLASH FLOODING
INCREASES...THEN A FLASH FLOOD WATCH MAY BE NEEDED FOR PARTS OF
THE HYDRO SERVICE AREA TONIGHT INTO LABOR DAY.

RAINFALL AMOUNTS WILL CONTINUE TO BE QUITE VARIABLE DUE TO WHERE
THE CONVECTION DEVELOPS AND MOVES. SOME LOCATIONS RECEIVED 1 TO 3
INCHES OF RAINFALL YESTERDAY INTO THIS MORNING /SRN TACONICS...NW
CT...SRN BERKSHIRES...HELDERBERGS AND PORTIONS OF ALY CTY/. THE
SOILS ARE BIT MORE SATURATED IN THESE AREAS...AND THEY WILL HAVE
TO MONITORED FOR ANY HYDRO ISSUES.

COOLER AND DRIER WEATHER WILL MOVE BACK INTO THE HSA FOR THE MID
WEEK ALLOWING STREAMS AND RIVERS TO RECEDE FROM THE RAINFALL.

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.

&&

.CLIMATE...
THE AVERAGE MONTHLY TEMPERATURES FOR AUGUST 2013 CAME IN BELOW
NORMAL FOR ALBANY...GLENS FALLS...POUGHKEEPSIE...BENNINGTON AND
PITTSFIELD.

THE METEOROLOGICAL SUMMER FOR 2013 COMES IN AT THE 7TH WETTEST FOR
ALBANY SINCE 1826 AND THE 4TH WETTEST FOR POUGHKEEPSIE SINCE 1949.
THE AVERAGE TEMPERATURES FOR THE SUMMER WERE AROUND 1.5 DEGREES
ABOVE NORMAL FOR ALL 5 CLIMATE LOCATIONS.

PLEASE REFER TO OUR FACEBOOK POSTS OR TWEETS SUMMARIZING AUGUST 2013
AND THE SUMMER.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...WASULA
NEAR TERM...FRUGIS/JPV/WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...FRUGIS
FIRE WEATHER...WASULA
HYDROLOGY...SND/WASULA
CLIMATE...IAA








AREA FORECAST DISCUSSION

NWS ALBANY NY

 110 PM EDT SUN SEP 1 2013

.SYNOPSIS...
A PERSISTENT WARM AND HUMID AIR MASS FOR THE FIRST DAY
OF SEPTEMBER WILL REMAIN OVER THE REGION THROUGH LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 110 PM EDT...VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW A
GOOD DEAL OF CLOUDINESS AROUND THE REGION EARLY THIS AFTERNOON. A
DIFFUSE SFC FRONTAL BOUNDARY REMAINS SITUATED NEAR THE FAR
SOUTHEASTERN CORNER OF THE CWA. SHOWER AND THUNDERSTORM ACTIVITY
HAS INCREASED ACROSS MAINLY ULSTER...DUTCHESS AND LITCHFIELD
COUNTIES SO RAISED POPS TO LIKELY IN THESE AREA. SPC RAP ANALYSIS
SHOW A DECENT INSTABILITY GRADIENT ACROSS THE AREA WITH ONLY
AROUND 500 J/KG OF CAPE ACROSS THE ADIRONDACKS...WITH AROUND 2000
J/KG SOUTH AND EAST OF ALBANY. THE MOST UNSTABLE AREA COINCIDES
WITH WHERE THE SURFACE BOUNDARY IS...THUS THE HIGHER POPS. LOWERED
TO SLIGHT CHANCE FOR MUCH OF THE WESTERN/SOUTHERN ADIRONDACKS DUE
TO LACK OF FORCING.

THE DIFFUSE FRONTAL BOUNDARY WILL CREEP BACK NORTHWARD DURING THE
THE REST OF THE DAYLIGHT HOURS...WITH POP-UP SHOWERS AND
THUNDERSTORMS EXPECTED TO INCREASE IN COVERAGE ESPECIALLY SOUTH
AND EAST OF ALBANY. THE COVERAGE AREA SHOULD BE A LITTLE LESS
THAN YESTERDAY...WITH THE MOST ACTIVITY FOR SOUTHERN AREAS CLOSER
TO THE BOUNDARY. THE PWAT VALUE ON THE 12Z KALY SOUNDING WAS 1.52
INCHES...WHICH IS SLIGHTLY ABOVE NORMAL...SO ANY THUNDERSTORM WILL
BE CAPABLE OF PRODUCING HEAVY DOWNPOURS IN A SHORT PERIOD OF TIME.
ENHANCED WORDING IN THE GRIDS AND HWO PRODUCT WAS CONTINUED FOR
HEAVY RAINFALL WITH ANY CONVECTION TODAY FOR SOUTHEASTERN PARTS OF
THE AREA...WHICH WILL HAVE BETTER COVERAGE DUE TO BEING MORE
CLOSELY LOCATED TO THE SFC FRONTAL BOUNDARY.

THE SBCAPE VALUES FROM BOTH THE GFS AND NAM ARE A BIT LOWER TODAY
IN THE 500-1000 J/KG WITH POCKETS OF 1500-2000 J/KG SOUTH OF THE
CAPITAL DISTRICT WHERE THE SFC DEWPTS WILL BE IN THE U60S TO L70S.
THE PROJECTED VALUE FOR THIS AFTN BASED ON THE 12Z KALY SOUNDING
WAS AROUND 1085 J/KG. NOT ANTICIPATING ANY SEVERE WEATHER AGAIN
WITH WEAK MID LEVEL LAPSE RATES AND WEAK DEEP SHEAR PREVENTING ANY
DEEP WELL ORGANIZED CONVECTION.

H850 TEMPS IN THE +15C TO +17C RANGE WITH SOME SUNSHINE FOR A FEW
HOURS WILL ALLOW TEMPS TO GET IN THE M70S TO M80S ACROSS THE FCST
AREA. THE NRN ZONES MAY ACTUALLY HAVE MORE SUNSHINE TODAY...SINCE
THE WEAK BOUNDARY WILL BE ACROSS THE SOUTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...A STRONG UPPER LEVEL LOW WILL BE CHURNING EASTWARD FROM
THE UPPER GREAT LAKES REGION AND ONTARIO. THE LARGE SFC TROUGH OF
LOW PRESSURE WILL BE MOVING TOWARDS THE NORTHEAST. ONE SHORT-WAVE
ASSOCIATED WITH THE SYSTEM IN THE SOUTHWEST FLOW ALOFT WILL IMPACT
THE REGION SHORTLY BEFORE OR JUST AFTER MIDNIGHT WITH SHOWERS AND
EMBEDDED THUNDERSTORMS...OR EVEN A DEVELOPING STRATIFORM RAIN
SHIELD. THE QG LIFT STRENGTHENS BTWN 06Z-12Z DUE TO THE
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION AND WEAK THERMAL
ADVECTION. THE RAIN INTENSIFIES DUE TO A PLUME OF UPPER LEVEL
DIVERGENCE MOVING OVER ERN NY. POPS WERE KEPT IN THE LIKELY OR
LOW-CATEGORICAL RANGE. MIN TEMPS WILL BE OF THE WET BULB VARIETY
IN THE M60S TO NEAR 70F WITH SOME L60S OVER THE MTNS.

LABOR DAY...THE LEAD SHORT-WAVE CROSSES THE REGION IN THE
MORNING/EARLY PM. THE RAINFALL COULD INCREASE IN INTENSITY AGAIN IN
THE EARLY TO MID PM...AS PORTIONS OF ERN NY WILL BE NEAR THE RIGHT
ENTRANCE REGION OF A 60-70 KT H250 JET STREAK. ALSO...SOME BREAKS
IN THE CLOUDS COULD ALLOW FOR ENOUGH DESTABILIZATION FOR SOME
STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. THIS SET-UP IS STILL A
BIT NEBULOUS...BUT A STRONG COLD FRONT WILL BE APPROACHING IN THE
MID TO LATE PM. STRONG CONVERGENCE IS EXPECTED WITH THE BOUNDARY.
PLENTY OF LOW-LEVEL MOISTURE WILL BE IN PLACE WITH PWATS STILL A
COUPLE OF STD DEVS ABOVE NORMAL. SBCAPES VALUES MAY RANGE FROM
500-1500 J/KG WITH THE 0-6 KM BULK SHEAR VALUES RAMPING UP TO
25-35 KTS. THE SEE TEXT FROM SPC LOOKS FINE...BECAUSE THE SEVERE
POTENTIAL WILL BE CONDITIONAL TO THE AMOUNT OF SFC HEATING THAT
OCCURS...AND THE TIMING OF THESE IMPULSES ROTATING AROUND THE UPPER
LEVEL LOW. THE MID LEVEL LAPSE RATES STILL DON/T FALL TO 6.5 C/KM
OR LOWER UNTIL AFTER DARK. HEAVY RAINFALL LOOKS LIKE A GOOD BET
WITH A WIDESPREAD HALF AN INCH TO AN INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS TO 2 INCHES. WIDESPREAD FLASH FLOODING DOES NOT
LOOK LIKELY AT THIS TIME...BUT THE POSSIBILITY WILL CONTINUE TO BE
MONITORED.

OUR FORECAST REFLECTS MAX TEMPS CLOSER TO THE COOLER NAM MOS
VALUES FOR THE HOLIDAY WITH U70S TO L80S IN THE VALLEYS...AND
U60S TO M70S OVER THE HIGH PEAKS.

MON NIGHT...THE SHOWERS AND THUNDERSTORMS WILL END WITH THE
PASSAGE OF THE FIRST COLD FRONT. THE BETTER COLD ADVECTION DOES
NOT ARRIVE UNTIL AFTER DAY BREAK. LOWS WILL RANGE FROM THE MID AND
U50S OVER THE NW ZONES TO LOWER TO M60S OVER THE SE ZONES.

TUE-TUE NIGHT...MUCH COOLER AIR INVADES THE FCST AREA...AS THE
HUMIDITY BREAKS. THE UPPER LEVEL TROUGH AXIS...AND A SECONDARY
COLD FRONT MOVE THROUGH DURING THE DAY WITH ISOLD-SCT SHOWERS
POSSIBLE BASED ON THE NAM/GFS/ECMWF/CANADIAN GUIDANCE. H850 TEMPS
FALL TO AROUND +10C NEAR THE CAPITAL REGION. THE COLD POOL WILL
HELP FOCUS INSTABILITY SHOWERS. MAX TEMPS WILL BE IN THE MID 70S
TO L80S IN THE VALLEYS...WITH M60S TO M70S OVER THE MTNS. LOWS
WILL COOL OFF INTO THE 50S FOR MOST OF THE REGION TUE NIGHT...WITH
SOME U40S OVER THE MTNS.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
THE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE NORTHEAST WILL
REMAIN UNDER A LONGWAVE TROUGH FOR THE PERIOD.

WE ARE LOOKING FOR PLEASANT DAY WEDNESDAY AS HIGHER PRESSURE BUILDS
IN WITH SEASONABLY WARM TEMPERATURES. A COLD FRONT IS FORECAST TO
MOVE ACROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY USHERING IN A
MORE AUTUMN-LIKE AIRMASS AS CANADIAN HIGH PRESSURE BUILDS IN ITS
WAKE. AN INCREASE CLOUDS ALONG WITH ISOLATED SHOWERS SHOULD ACCOMPANY
THE BOUNDARY. TEMPERATURES THURSDAY AND FRIDAY SHOULD RUN ABOUT 5
DEGREES BELOW NORMAL.

TEMPERATURES ARE ANTICIPATED TO MODERATE BACK TO SEASONABLE LEVELS
FOR THE START OF THE WEEKEND AS THE SURFACE HIGH SHIFTS TO OUR
SOUTHEAST ALLOWING A SOUTH-SOUTHWEST FLOW TO DEVELOP.
HOWEVER...THERE ARE MODEL DIFFERENCES DEALING WITH THE TIMING AND
STRENGTH OF INDIVIDUALS SHORT WAVE ROTATING ABOUT AN UPPER LOW
OVER EASTERN CANADA. THIS WILL IMPACT THE TIMING OF FRONTAL
BOUNDARIES ACROSS THE REGION NEXT WEEKEND. AT THIS TIME...IT APPEARS
A WARM FRONT SHOULD MOVE INTO/THROUGH THE REGION ON SATURDAY AS A LOW
PASSES TO OUR NORTH.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
A MUGGY AIRMASS IS IN PLACE WITH A STALLED BOUNDARY ACROSS THE
REGION. GUIDANCE INDICATES THE FRONTAL BOUNDARY WILL WEAKEN AND
DISSIPATE TODAY. ISOLATED SHOWERS/THUNDERSTORMS HAVE RECENTLY
DEVELOPED TO THE EAST OF KPOU IN MORE UNSTABLE AIR TO THE SOUTH AND
EAST OF THE BOUNDARY. OVERALL THE LULL IN THE CONVECTION IS EXPECTED
TO CONTINUE ACROSS THE LOCAL AREA INTO THIS AFTERNOON AS SOME WEAK
WEAK RIDGING OCCUR EARLY TODAY. CHANCES FOR STORMS WILL INCREASE BY
MID TO LATE AFTERNOON AND WITH NUMEROUS STORMS TONIGHT AS A STRONGER
SHORT WAVE APPROACHES AND HEIGHT FALLS ACROSS THE REGION.

MVFR TO LIFR CONDITIONS WILL IMPROVE TO VFR BY MID/LATE MORNING. VFR
CONDITIONS ARE THEN EXPECTED THROUGH MUCH OF THE DAY WITH CONDITIONS
LOWERING AS WE HEAD THROUGH THE EVENING AND CHANCES FOR SHOWERS AND
THUNDERSTORMS INCREASE. IFR CONDITIONS ARE EXPECTED TO DEVELOP AT
KGFL AND KPSF LATE TONIGHT WITH MVFR CONDITIONS PERSISTING AT KPOU
AND KALB.

A LIGHT SOUTH-SOUTHWEST FLOW IS EXPECTED TO DEVELOP DURING THE DAY
SUNDAY WITH LIGHT AND VARIABLE TO CALM WINDS EXPECTED AGAIN SUNDAY
NIGHT.

OUTLOOK...
MON NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
TUE-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED THE NEXT SEVERAL DAYS. A HUMID
AIR MASS WITH SEVERAL CHANCES OF RAINFALL WILL BE POSSIBLE INTO
TUESDAY.

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

HIGH RH VALUES OF 55 TO 75 PERCENT WILL OCCUR THIS AFTERNOON. THE
RH VALUES WILL RECOVER CLOSE TO 100 PERCENT MONDAY MORNING...AND
REMAIN HIGH IN THE AFTERNOON AT 65 TO 85 PERCENT.

EXPECT WINDS FROM THE SOUTHEAST OR SOUTH AT 5 TO 15 MPH TODAY.
LIGHT AND VARIABLE WINDS WILL OCCUR TONIGHT. SOUTH OR SOUTHWEST WINDS
OF 5 TO 15 MPH ARE FORECAST FOR LABOR DAY.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED OR ISOLATED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR
WIDESPREAD RAINFALL WILL BE TONIGHT AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. SOME LOCATIONS COULD GET A QUICK FEW
INCHES OF RAINFALL IN 3 HOURS OR LESS...AS WHAT OCCURRED ON
SATURDAY AND THIS MORNING.

ISOLATED URBAN...SMALL STREAM...AND POOR DRAINAGE FLOODING WILL BE
POSSIBLE THE REMAINDER OF THE HOLIDAY WEEKEND. SOME SUBSTANTIAL WITHIN
BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE SHOWERS AND STORMS
OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS TIME FRAME.

HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW MOVING
THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING TODAY INTO LABOR
DAY. IF THE POTENTIAL FOR WIDESPREAD FLASH FLOODING
INCREASES...THEN A FLASH FLOOD WATCH MAY BE NEEDED FOR PARTS OF
THE HYDRO SERVICE AREA TONIGHT INTO LABOR DAY.

RAINFALL AMOUNTS WILL CONTINUE TO BE QUITE VARIABLE DUE TO WHERE
THE CONVECTION DEVELOPS AND MOVES. SOME LOCATIONS RECEIVED 1 TO 3
INCHES OF RAINFALL YESTERDAY INTO THIS MORNING /SRN TACONICS...NW
CT...SRN BERKSHIRES...HELDERBERGS AND PORTIONS OF ALY CTY/. THE
SOILS ARE BIT MORE SATURATED IN THESE AREAS...AND THEY WILL HAVE
TO MONITORED FOR ANY HYDRO ISSUES.

COOLER AND DRIER WEATHER WILL MOVE BACK INTO THE HSA FOR THE MID
WEEK ALLOWING STREAMS AND RIVERS TO RECEDE FROM THE RAINFALL.

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.

&&

.CLIMATE...
THE AVERAGE MONTHLY TEMPERATURES FOR AUGUST 2013 CAME IN BELOW
NORMAL FOR ALBANY...GLENS FALLS...POUGHKEEPSIE...BENNINGTON AND
PITTSFIELD.

THE METEOROLOGICAL SUMMER FOR 2013 COMES IN AT THE 7TH WETTEST FOR
ALBANY SINCE 1826 AND THE 4TH WETTEST FOR POUGHKEEPSIE SINCE 1949.
THE AVERAGE TEMPERATURES FOR THE SUMMER WERE AROUND 1.5 DEGREES
ABOVE NORMAL FOR ALL 5 CLIMATE LOCATIONS.

PLEASE REFER TO OUR FACEBOOK POSTS OR TWEETS SUMMARIZING AUGUST 2013
AND THE SUMMER.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...WASULA
NEAR TERM...FRUGIS/JPV/WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA/FRUGIS
FIRE WEATHER...WASULA
HYDROLOGY...SND/WASULA
CLIMATE...IAA








AREA FORECAST DISCUSSION

NWS ALBANY NY

 739 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A PERSISTENT WARM AND HUMID AIR MASS FOR THE FIRST DAY
OF SEPTEMBER WILL REMAIN OVER THE REGION THROUGH LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 659 AM EDT...THE MINI MCS THAT FORMED ALONG THE FRONTAL
BOUNDARY AND SOUTH OF THE WEAK WAVE OF LOW PRESSURE MOVING ALONG
IT HAS SHIFTED DOWN STREAM NEAR CAPE COD. SOME DUAL POL QPE VALUES
OF 1 TO 3 INCHES OCCURRED OVER NW CT...SRN BERKS...AND THE SRN
TACONICS OF COLUMBIA AND EXTREME NE DUTCHES COUNTIES. THE KENX
RADAR AREA HAS BECOME QUIET WITH SUBSIDENCE IN THE WAKE OF THE
MCS. THE WATER VAPOR LOOP INDICATES LOTS OF MID AND UPPER LEVEL
DRY AIR HAS MOVED OVER UPSTATE NY AND PORTIONS OF WRN NEW ENGLAND.
THIS HAS ALLOWED PATCHY FOG AND SOME STRATUS TO FORM. CONDITIONS
REMAIN MUGGY FOR THE OPENING DAY OF SEPT. A FEW SHOWERS HAVE
POPPED UP OVER SRN DUTCHESS AND LITCHFIELD COUNTIES NEAR THE
DIFFUSE BOUNDARY. A MORE ROBUST THUNDERSTORM CLUSTER CONTINUES
S/SE OF LITCHFIELD CTY. POPS WERE RETRENDED BASED ON THE RADAR TRENDS.

THE MORNING WILL BEGIN DRY WITH LOTS OF CLOUDS FOR MOST OF THE
REGION. WEAK MID AND LOW LEVEL RIDGING WILL PROMOTE A QUIET START
OF THE DAY. HOWEVER...THE DIFFUSE FRONTAL BOUNDARY WILL CREEP
NORTHWARD FROM THE SRN TIER. POP-UP SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO FORM...AND OTHER SHOWERS AND THUNDERSTORMS MAY
INITIATE ALONG THE HIGHER TERRAIN DUE TO THE DIFFERENTIAL HEATING
BTWN THE MTNS AND VALLEYS BY THE MID PM. THE COVERAGE AREA SHOULD
BE A LITTLE LESS THAN YESTERDAY. THE GENERAL TREND FROM THE LATEST
3-KM HRRR BASE REF PRODUCT IS FOR THE SHOWERS/THUNDERSTORMS TO
INCREASE FROM THE CAPITAL REGION SOUTHWARD BTWN 15Z-18Z. SOME OF
THE SHOWERS AND THUNDERSTORMS COULD DUMP HVY AMOUNTS OF RAINFALL
WITH PWATS STILL RUNNING 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL
/1.25-1.75 INCH RANGE/ FOR THE START OF METEOROLOGICAL SUMMER. THE
SBCAPE VALUES FROM BOTH THE GFS AND NAM ARE A BIT LOWER TODAY IN
THE 500-1000 J/KG WITH POCKETS GREATER THAN 1000 J/KG SOUTH OF THE
CAPITAL DISTRICT WHERE THE SFC DEWPTS WILL BE IN THE U60S TO L70S.
NOT ANTICIPATING ANY SEVERE WEATHER AGAIN WITH WEAK MID LEVEL
LAPSE RATES AND WEAK DEEP SHEAR PREVENTING ANY DEEP WELL ORGANIZED
CONVECTION.

ENHANCED WORDING WAS CONTINUED FOR HEAVY RAINFALL WITH ANY
CONVECTION TODAY. H850 TEMPS IN THE +15C TO +17C RANGE WITH SOME
SUNSHINE FOR A FEW HOURS WILL ALLOW TEMPS TO GET IN THE M70S TO
M80S ACROSS THE FCST AREA. THE NRN ZONES MAY ACTUALLY HAVE MORE
SUNSHINE TODAY...SINCE THE WEAK BOUNDARY WILL BE ACROSS THE SOUTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...A STRONG UPPER LEVEL LOW WILL BE CHURNING EASTWARD FROM
THE UPPER GREAT LAKES REGION AND ONTARIO. THE LARGE SFC TROUGH OF
LOW PRESSURE WILL BE MOVING TOWARDS THE NORTHEAST. ONE SHORT-WAVE
ASSOCIATED WITH THE SYSTEM IN THE SOUTHWEST FLOW ALOFT WILL IMPACT
THE REGION SHORTLY BEFORE OR JUST AFTER MIDNIGHT WITH SHOWERS AND
EMBEDDED THUNDERSTORMS...OR EVEN A DEVELOPING STRATIFORM RAIN
SHIELD. THE QG LIFT STRENGTHENS BTWN 06Z-12Z DUE TO THE
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION AND WEAK THERMAL
ADVECTION. THE RAIN INTENSIFIES DUE TO A PLUME OF UPPER LEVEL
DIVERGENCE MOVING OVER ERN NY. POPS WERE KEPT IN THE LIKELY OR
LOW-CATEGORICAL RANGE. MIN TEMPS WILL BE OF THE WET BULB VARIETY
IN THE M60S TO NEAR 70F WITH SOME L60S OVER THE MTNS.

LABOR DAY...THE LEAD SHORT-WAVE CROSSES THE REGION IN THE
MORNING/EARLY PM. THE RAINFALL COULD INCREASE IN INTENSITY AGAIN IN
THE EARLY TO MID PM...AS PORTIONS OF ERN NY WILL BE NEAR THE RIGHT
ENTRANCE REGION OF A 60-70 KT H250 JET STREAK. ALSO...SOME BREAKS
IN THE CLOUDS COULD ALLOW FOR ENOUGH DESTABILIZATION FOR SOME
STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. THIS SET-UP IS STILL A
BIT NEBULOUS...BUT A STRONG COLD FRONT WILL BE APPROACHING IN THE
MID TO LATE PM. STRONG CONVERGENCE IS EXPECTED WITH THE BOUNDARY.
PLENTY OF LOW-LEVEL MOISTURE WILL BE IN PLACE WITH PWATS STILL A
COUPLE OF STD DEVS ABOVE NORMAL. SBCAPES VALUES MAY RANGE FROM
500-1500 J/KG WITH THE 0-6 KM BULK SHEAR VALUES RAMPING UP TO
25-35 KTS. THE SEE TEXT FROM SPC LOOKS FINE...BECAUSE THE SEVERE
POTENTIAL WILL BE CONDITIONAL TO THE AMOUNT OF SFC HEATING THAT
OCCURS...AND THE TIMING OF THESE IMPULSES ROTATING AROUND THE UPPER
LEVEL LOW. THE MID LEVEL LAPSE RATES STILL DON/T FALL TO 6.5 C/KM
OR LOWER UNTIL AFTER DARK. HEAVY RAINFALL LOOKS LIKE A GOOD BET
WITH A WIDESPREAD HALF AN INCH TO AN INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS TO 2 INCHES. WIDESPREAD FLASH FLOODING DOES NOT
LOOK LIKELY AT THIS TIME...BUT THE POSSIBILITY WILL CONTINUE TO BE
MONITORED.

OUR FORECAST REFLECTS MAX TEMPS CLOSER TO THE COOLER NAM MOS
VALUES FOR THE HOLIDAY WITH U70S TO L80S IN THE VALLEYS...AND
U60S TO M70S OVER THE HIGH PEAKS.

MON NIGHT...THE SHOWERS AND THUNDERSTORMS WILL END WITH THE
PASSAGE OF THE FIRST COLD FRONT. THE BETTER COLD ADVECTION DOES
NOT ARRIVE UNTIL AFTER DAY BREAK. LOWS WILL RANGE FROM THE MID AND
U50S OVER THE NW ZONES TO LOWER TO M60S OVER THE SE ZONES.

TUE-TUE NIGHT...MUCH COOLER AIR INVADES THE FCST AREA...AS THE
HUMIDITY BREAKS. THE UPPER LEVEL TROUGH AXIS...AND A SECONDARY
COLD FRONT MOVE THROUGH DURING THE DAY WITH ISOLD-SCT SHOWERS
POSSIBLE BASED ON THE NAM/GFS/ECMWF/CANADIAN GUIDANCE. H850 TEMPS
FALL TO AROUND +10C NEAR THE CAPITAL REGION. THE COLD POOL WILL
HELP FOCUS INSTABILITY SHOWERS. MAX TEMPS WILL BE IN THE MID 70S
TO L80S IN THE VALLEYS...WITH M60S TO M70S OVER THE MTNS. LOWS
WILL COOL OFF INTO THE 50S FOR MOST OF THE REGION TUE NIGHT...WITH
SOME U40S OVER THE MTNS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE NORTHEAST WILL
REMAIN UNDER A LONGWAVE TROUGH FOR THE PERIOD.

WE ARE LOOKING FOR PLEASANT DAY WEDNESDAY AS HIGHER PRESSURE BUILDS
IN WITH SEASONABLY WARM TEMPERATURES. A COLD FRONT IS FORECAST TO
MOVE ACROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY USHERING IN A
MORE AUTUMN-LIKE AIRMASS AS CANADIAN HIGH PRESSURE BUILDS IN ITS
WAKE. AN INCREASE CLOUDS ALONG WITH ISOLATED SHOWERS SHOULD ACCOMPANY
THE BOUNDARY. TEMPERATURES THURSDAY AND FRIDAY SHOULD RUN ABOUT 5
DEGREES BELOW NORMAL.

TEMPERATURES ARE ANTICIPATED TO MODERATE BACK TO SEASONABLE LEVELS
FOR THE START OF THE WEEKEND AS THE SURFACE HIGH SHIFTS TO OUR
SOUTHEAST ALLOWING A SOUTH-SOUTHWEST FLOW TO DEVELOP.
HOWEVER...THERE ARE MODEL DIFFERENCES DEALING WITH THE TIMING AND
STRENGTH OF INDIVIDUALS SHORT WAVE ROTATING ABOUT AN UPPER LOW
OVER EASTERN CANADA. THIS WILL IMPACT THE TIMING OF FRONTAL
BOUNDARIES ACROSS THE REGION NEXT WEEKEND. AT THIS TIME...IT APPEARS
A WARM FRONT SHOULD MOVE INTO/THROUGH THE REGION ON SATURDAY AS A LOW
PASSES TO OUR NORTH.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A MUGGY AIRMASS IS IN PLACE WITH A STALLED BOUNDARY ACROSS THE
REGION. GUIDANCE INDICATES THE FRONTAL BOUNDARY WILL WEAKEN AND
DISSIPATE TODAY. ISOLATED SHOWERS/THUNDERSTORMS HAVE RECENTLY
DEVELOPED TO THE EAST OF KPOU IN MORE UNSTABLE AIR TO THE SOUTH AND
EAST OF THE BOUNDARY. OVERALL THE LULL IN THE CONVECTION IS EXPECTED
TO CONTINUE ACROSS THE LOCAL AREA INTO THIS AFTERNOON AS SOME WEAK
WEAK RIDGING OCCUR EARLY TODAY. CHANCES FOR STORMS WILL INCREASE BY
MID TO LATE AFTERNOON AND WITH NUMEROUS STORMS TONIGHT AS A STRONGER
SHORT WAVE APPROACHES AND HEIGHT FALLS ACROSS THE REGION.

MVFR TO LIFR CONDITIONS WILL IMPROVE TO VFR BY MID/LATE MORNING. VFR
CONDITIONS ARE THEN EXPECTED THROUGH MUCH OF THE DAY WITH CONDITIONS
LOWERING AS WE HEAD THROUGH THE EVENING AND CHANCES FOR SHOWERS AND
THUNDERSTORMS INCREASE. IFR CONDITIONS ARE EXPECTED TO DEVELOP AT
KGFL AND KPSF LATE TONIGHT WITH MVFR CONDITIONS PERSISTING AT KPOU
AND KALB.

A LIGHT SOUTH-SOUTHWEST FLOW IS EXPECTED TO DEVELOP DURING THE DAY
SUNDAY WITH LIGHT AND VARIABLE TO CALM WINDS EXPECTED AGAIN SUNDAY
NIGHT.

OUTLOOK...
MON NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
TUE-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED THE NEXT SEVERAL DAYS. A HUMID
AIR MASS WITH SEVERAL CHANCES OF RAINFALL WILL BE POSSIBLE INTO
TUESDAY.

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

HIGH RH VALUES OF 55 TO 75 PERCENT WILL OCCUR THIS AFTERNOON. THE
RH VALUES WILL RECOVER CLOSE TO 100 PERCENT MONDAY MORNING...AND
REMAIN HIGH IN THE AFTERNOON AT 65 TO 85 PERCENT.

EXPECT WINDS FROM THE SOUTHEAST OR SOUTH AT 5 TO 15 MPH TODAY.
LIGHT AND VARIABLE WINDS WILL OCCUR TONIGHT. SOUTH OR SOUTHWEST WINDS
OF 5 TO 15 MPH ARE FORECAST FOR LABOR DAY.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED OR ISOLATED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR
WIDESPREAD RAINFALL WILL BE TONIGHT AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. SOME LOCATIONS COULD GET A QUICK FEW
INCHES OF RAINFALL IN 3 HOURS OR LESS...AS WHAT OCCURRED ON
SATURDAY AND THIS MORNING.

ISOLATED URBAN...SMALL STREAM...AND POOR DRAINAGE FLOODING WILL BE
POSSIBLE THE REMAINDER OF THE HOLIDAY WEEKEND. SOME SUBSTANTIAL WITHIN
BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE SHOWERS AND STORMS
OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS TIME FRAME.

HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW MOVING
THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING TODAY INTO LABOR
DAY. IF THE POTENTIAL FOR WIDESPREAD FLASH FLOODING
INCREASES...THEN A FLASH FLOOD WATCH MAY BE NEEDED FOR PARTS OF
THE HYDRO SERVICE AREA TONIGHT INTO LABOR DAY.

RAINFALL AMOUNTS WILL CONTINUE TO BE QUITE VARIABLE DUE TO WHERE
THE CONVECTION DEVELOPS AND MOVES. SOME LOCATIONS RECEIVED 1 TO 3
INCHES OF RAINFALL YESTERDAY INTO THIS MORNING /SRN TACONICS...NW
CT...SRN BERKSHIRES...HELDERBERGS AND PORTIONS OF ALY CTY/. THE
SOILS ARE BIT MORE SATURATED IN THESE AREAS...AND THEY WILL HAVE
TO MONITORED FOR ANY HYDRO ISSUES.

COOLER AND DRIER WEATHER WILL MOVE BACK INTO THE HSA FOR THE MID
WEEK ALLOWING STREAMS AND RIVERS TO RECEDE FROM THE RAINFALL.

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.

&&

.CLIMATE...
THE AVERAGE MONTHLY TEMPERATURES FOR AUGUST 2013 CAME IN BELOW
NORMAL FOR ALBANY...GLENS FALLS...POUGHKEEPSIE...BENNINGTON AND
PITTSFIELD.

THE METEOROLOGICAL SUMMER FOR 2013 COMES IN AT THE 7TH WETTEST FOR
ALBANY SINCE 1826 AND THE 4TH WETTEST FOR POUGHKEEPSIE SINCE 1949.
THE AVERAGE TEMPERATURES FOR THE SUMMER WERE AROUND 1.5 DEGREES
ABOVE NORMAL FOR ALL 5 CLIMATE LOCATIONS.

PLEASE REFER TO OUR FACEBOOK POSTS OR TWEETS SUMMARIZING AUGUST 2013
AND THE SUMMER.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA/FRUGIS
FIRE WEATHER...WASULA
HYDROLOGY...SND/WASULA
CLIMATE...IAA








AREA FORECAST DISCUSSION

NWS ALBANY NY

 701 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A PERSISTENT WARM AND HUMID AIR MASS FOR THE FIRST DAY
OF SEPTEMBER WILL REMAIN OVER THE REGION THROUGH LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 659 AM EDT...THE MINI MCS THAT FORMED ALONG THE FRONTAL
BOUNDARY AND SOUTH OF THE WEAK WAVE OF LOW PRESSURE MOVING ALONG
IT HAS SHIFTED DOWN STREAM NEAR CAPE COD. SOME DUAL POL QPE VALUES
OF 1 TO 3 INCHES OCCURRED OVER NW CT...SRN BERKS...AND THE SRN
TACONICS OF COLUMBIA AND EXTREME NE DUTCHES COUNTIES. THE KENX
RADAR AREA HAS BECOME QUIET WITH SUBSIDENCE IN THE WAKE OF THE
MCS. THE WATER VAPOR LOOP INDICATES LOTS OF MID AND UPPER LEVEL
DRY AIR HAS MOVED OVER UPSTATE NY AND PORTIONS OF WRN NEW ENGLAND.
THIS HAS ALLOWED PATCHY FOG AND SOME STRATUS TO FORM. CONDITIONS
REMAIN MUGGY FOR THE OPENING DAY OF SEPT. A FEW SHOWERS HAVE
POPPED UP OVER SRN DUTCHESS AND LITCHFIELD COUNTIES NEAR THE
DIFFUSE BOUNDARY. A MORE ROBUST THUNDERSTORM CLUSTER CONTINUES
S/SE OF LITCHFIELD CTY. POPS WERE RETRENDED BASED ON THE RADAR TRENDS.

THE MORNING WILL BEGIN DRY WITH LOTS OF CLOUDS FOR MOST OF THE
REGION. WEAK MID AND LOW LEVEL RIDGING WILL PROMOTE A QUIET START
OF THE DAY. HOWEVER...THE DIFFUSE FRONTAL BOUNDARY WILL CREEP
NORTHWARD FROM THE SRN TIER. POP-UP SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO FORM...AND OTHER SHOWERS AND THUNDERSTORMS MAY
INITIATE ALONG THE HIGHER TERRAIN DUE TO THE DIFFERENTIAL HEATING
BTWN THE MTNS AND VALLEYS BY THE MID PM. THE COVERAGE AREA SHOULD
BE A LITTLE LESS THAN YESTERDAY. THE GENERAL TREND FROM THE LATEST
3-KM HRRR BASE REF PRODUCT IS FOR THE SHOWERS/THUNDERSTORMS TO
INCREASE FROM THE CAPITAL REGION SOUTHWARD BTWN 15Z-18Z. SOME OF
THE SHOWERS AND THUNDERSTORMS COULD DUMP HVY AMOUNTS OF RAINFALL
WITH PWATS STILL RUNNING 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL
/1.25-1.75 INCH RANGE/ FOR THE START OF METEOROLOGICAL SUMMER. THE
SBCAPE VALUES FROM BOTH THE GFS AND NAM ARE A BIT LOWER TODAY IN
THE 500-1000 J/KG WITH POCKETS GREATER THAN 1000 J/KG SOUTH OF THE
CAPITAL DISTRICT WHERE THE SFC DEWPTS WILL BE IN THE U60S TO L70S.
NOT ANTICIPATING ANY SEVERE WEATHER AGAIN WITH WEAK MID LEVEL
LAPSE RATES AND WEAK DEEP SHEAR PREVENTING ANY DEEP WELL ORGANIZED
CONVECTION.

ENHANCED WORDING WAS CONTINUED FOR HEAVY RAINFALL WITH ANY
CONVECTION TODAY. H850 TEMPS IN THE +15C TO +17C RANGE WITH SOME
SUNSHINE FOR A FEW HOURS WILL ALLOW TEMPS TO GET IN THE M70S TO
M80S ACROSS THE FCST AREA. THE NRN ZONES MAY ACTUALLY HAVE MORE
SUNSHINE TODAY...SINCE THE WEAK BOUNDARY WILL BE ACROSS THE SOUTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...A STRONG UPPER LEVEL LOW WILL BE CHURNING EASTWARD FROM
THE UPPER GREAT LAKES REGION AND ONTARIO. THE LARGE SFC TROUGH OF
LOW PRESSURE WILL BE MOVING TOWARDS THE NORTHEAST. ONE SHORT-WAVE
ASSOCIATED WITH THE SYSTEM IN THE SOUTHWEST FLOW ALOFT WILL IMPACT
THE REGION SHORTLY BEFORE OR JUST AFTER MIDNIGHT WITH SHOWERS AND
EMBEDDED THUNDERSTORMS...OR EVEN A DEVELOPING STRATIFORM RAIN
SHIELD. THE QG LIFT STRENGTHENS BTWN 06Z-12Z DUE TO THE
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION AND WEAK THERMAL
ADVECTION. THE RAIN INTENSIFIES DUE TO A PLUME OF UPPER LEVEL
DIVERGENCE MOVING OVER ERN NY. POPS WERE KEPT IN THE LIKELY OR
LOW-CATEGORICAL RANGE. MIN TEMPS WILL BE OF THE WET BULB VARIETY
IN THE M60S TO NEAR 70F WITH SOME L60S OVER THE MTNS.

LABOR DAY...THE LEAD SHORT-WAVE CROSSES THE REGION IN THE
MORNING/EARLY PM. THE RAINFALL COULD INCREASE IN INTENSITY AGAIN IN
THE EARLY TO MID PM...AS PORTIONS OF ERN NY WILL BE NEAR THE RIGHT
ENTRANCE REGION OF A 60-70 KT H250 JET STREAK. ALSO...SOME BREAKS
IN THE CLOUDS COULD ALLOW FOR ENOUGH DESTABILIZATION FOR SOME
STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. THIS SET-UP IS STILL A
BIT NEBULOUS...BUT A STRONG COLD FRONT WILL BE APPROACHING IN THE
MID TO LATE PM. STRONG CONVERGENCE IS EXPECTED WITH THE BOUNDARY.
PLENTY OF LOW-LEVEL MOISTURE WILL BE IN PLACE WITH PWATS STILL A
COUPLE OF STD DEVS ABOVE NORMAL. SBCAPES VALUES MAY RANGE FROM
500-1500 J/KG WITH THE 0-6 KM BULK SHEAR VALUES RAMPING UP TO
25-35 KTS. THE SEE TEXT FROM SPC LOOKS FINE...BECAUSE THE SEVERE
POTENTIAL WILL BE CONDITIONAL TO THE AMOUNT OF SFC HEATING THAT
OCCURS...AND THE TIMING OF THESE IMPULSES ROTATING AROUND THE UPPER
LEVEL LOW. THE MID LEVEL LAPSE RATES STILL DON/T FALL TO 6.5 C/KM
OR LOWER UNTIL AFTER DARK. HEAVY RAINFALL LOOKS LIKE A GOOD BET
WITH A WIDESPREAD HALF AN INCH TO AN INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS TO 2 INCHES. WIDESPREAD FLASH FLOODING DOES NOT
LOOK LIKELY AT THIS TIME...BUT THE POSSIBILITY WILL CONTINUE TO BE
MONITORED.

OUR FORECAST REFLECTS MAX TEMPS CLOSER TO THE COOLER NAM MOS
VALUES FOR THE HOLIDAY WITH U70S TO L80S IN THE VALLEYS...AND
U60S TO M70S OVER THE HIGH PEAKS.

MON NIGHT...THE SHOWERS AND THUNDERSTORMS WILL END WITH THE
PASSAGE OF THE FIRST COLD FRONT. THE BETTER COLD ADVECTION DOES
NOT ARRIVE UNTIL AFTER DAY BREAK. LOWS WILL RANGE FROM THE MID AND
U50S OVER THE NW ZONES TO LOWER TO M60S OVER THE SE ZONES.

TUE-TUE NIGHT...MUCH COOLER AIR INVADES THE FCST AREA...AS THE
HUMIDITY BREAKS. THE UPPER LEVEL TROUGH AXIS...AND A SECONDARY
COLD FRONT MOVE THROUGH DURING THE DAY WITH ISOLD-SCT SHOWERS
POSSIBLE BASED ON THE NAM/GFS/ECMWF/CANADIAN GUIDANCE. H850 TEMPS
FALL TO AROUND +10C NEAR THE CAPITAL REGION. THE COLD POOL WILL
HELP FOCUS INSTABILITY SHOWERS. MAX TEMPS WILL BE IN THE MID 70S
TO L80S IN THE VALLEYS...WITH M60S TO M70S OVER THE MTNS. LOWS
WILL COOL OFF INTO THE 50S FOR MOST OF THE REGION TUE NIGHT...WITH
SOME U40S OVER THE MTNS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE NORTHEAST WILL
REMAIN UNDER A LONGWAVE TROUGH FOR THE PERIOD.

WE ARE LOOKING FOR PLEASANT DAY WEDNESDAY AS HIGHER PRESSURE BUILDS
IN WITH SEASONABLY WARM TEMPERATURES. A COLD FRONT IS FORECAST TO
MOVE ACROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY USHERING IN A
MORE AUTUMN-LIKE AIRMASS AS CANADIAN HIGH PRESSURE BUILDS IN ITS
WAKE. AN INCREASE CLOUDS ALONG WITH ISOLATED SHOWERS SHOULD ACCOMPANY
THE BOUNDARY. TEMPERATURES THURSDAY AND FRIDAY SHOULD RUN ABOUT 5
DEGREES BELOW NORMAL.

TEMPERATURES ARE ANTICIPATED TO MODERATE BACK TO SEASONABLE LEVELS
FOR THE START OF THE WEEKEND AS THE SURFACE HIGH SHIFTS TO OUR
SOUTHEAST ALLOWING A SOUTH-SOUTHWEST FLOW TO DEVELOP.
HOWEVER...THERE ARE MODEL DIFFERENCES DEALING WITH THE TIMING AND
STRENGTH OF INDIVIDUALS SHORT WAVE ROTATING ABOUT AN UPPER LOW
OVER EASTERN CANADA. THIS WILL IMPACT THE TIMING OF FRONTAL
BOUNDARIES ACROSS THE REGION NEXT WEEKEND. AT THIS TIME...IT APPEARS
A WARM FRONT SHOULD MOVE INTO/THROUGH THE REGION ON SATURDAY AS A LOW
PASSES TO OUR NORTH.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A MUGGY AIRMASS IS IN PLACE WITH A STALLED BOUNDARY ACROSS THE
REGION. GUIDANCE INDICATES THE FRONTAL BOUNDARY WILL WEAKEN AND
DISSIPATE TODAY. ISOLATED SHOWERS/THUNDERSTORMS HAVE RECENTLY
DEVELOPED TO THE EAST OF KPOU IN MORE UNSTABLE AIR TO THE SOUTH AND
EAST OF THE BOUNDARY. OVERALL THE LULL IN THE CONVECTION IS EXPECTED
TO CONTINUE ACROSS THE LOCAL AREA INTO THIS AFTERNOON AS SOME WEAK
WEAK RIDGING OCCUR EARLY TODAY. CHANCES FOR STORMS WILL INCREASE BY
MID TO LATE AFTERNOON AND WITH NUMEROUS STORMS TONIGHT AS A STRONGER
SHORT WAVE APPROACHES AND HEIGHT FALLS ACROSS THE REGION.

MVFR TO LIFR CONDITIONS WILL IMPROVE TO VFR BY MID/LATE MORNING. VFR
CONDITIONS ARE THEN EXPECTED THROUGH MUCH OF THE DAY WITH CONDITIONS
LOWERING AS WE HEAD THROUGH THE EVENING AND CHANCES FOR SHOWERS AND
THUNDERSTORMS INCREASE. IFR CONDITIONS ARE EXPECTED TO DEVELOP AT
KGFL AND KPSF LATE TONIGHT WITH MVFR CONDITIONS PERSISTING AT KPOU
AND KALB.

A LIGHT SOUTH-SOUTHWEST FLOW IS EXPECTED TO DEVELOP DURING THE DAY
SUNDAY WITH LIGHT AND VARIABLE TO CALM WINDS EXPECTED AGAIN SUNDAY
NIGHT.

OUTLOOK...
MON NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
TUE-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED THE NEXT SEVERAL DAYS. A HUMID
AIR MASS WITH SEVERAL CHANCES OF RAINFALL WILL BE POSSIBLE INTO
TUESDAY.

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

HIGH RH VALUES OF 55 TO 75 PERCENT WILL OCCUR THIS AFTERNOON. THE
RH VALUES WILL RECOVER CLOSE TO 100 PERCENT MONDAY MORNING...AND
REMAIN HIGH IN THE AFTERNOON AT 65 TO 85 PERCENT.

EXPECT WINDS FROM THE SOUTHEAST OR SOUTH AT 5 TO 15 MPH TODAY.
LIGHT AND VARIABLE WINDS WILL OCCUR TONIGHT. SOUTH OR SOUTHWEST WINDS
OF 5 TO 15 MPH ARE FORECAST FOR LABOR DAY.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED OR ISOLATED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR
WIDESPREAD RAINFALL WILL BE TONIGHT AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. SOME LOCATIONS COULD GET A QUICK FEW
INCHES OF RAINFALL IN 3 HOURS OR LESS...AS WHAT OCCURRED ON
SATURDAY AND THIS MORNING.

ISOLATED URBAN...SMALL STREAM...AND POOR DRAINAGE FLOODING WILL BE
POSSIBLE THE REMAINDER OF THE HOLIDAY WEEKEND. SOME SUBSTANTIAL WITHIN
BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE SHOWERS AND STORMS
OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS TIME FRAME.

HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW MOVING
THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING TODAY INTO LABOR
DAY. IF THE POTENTIAL FOR WIDESPREAD FLASH FLOODING
INCREASES...THEN A FLASH FLOOD WATCH MAY BE NEEDED FOR PARTS OF
THE HYDRO SERVICE AREA TONIGHT INTO LABOR DAY.

RAINFALL AMOUNTS WILL CONTINUE TO BE QUITE VARIABLE DUE TO WHERE
THE CONVECTION DEVELOPS AND MOVES. SOME LOCATIONS RECEIVED 1 TO 3
INCHES OF RAINFALL YESTERDAY INTO THIS MORNING /SRN TACONICS...NW
CT...SRN BERKSHIRES...HELDERBERGS AND PORTIONS OF ALY CTY/. THE
SOILS ARE BIT MORE SATURATED IN THESE AREAS...AND THEY WILL HAVE
TO MONITORED FOR ANY HYDRO ISSUES.

COOLER AND DRIER WEATHER WILL MOVE BACK INTO THE HSA FOR THE MID
WEEK ALLOWING STREAMS AND RIVERS TO RECEDE FROM THE RAINFALL.

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.

&&

.CLIMATE...
THE AVERAGE MONTHLY TEMPERATURES FOR AUGUST 2013 CAME IN BELOW
NORMAL FOR ALBANY...GLENS FALLS...POUGHKEEPSIE...BENNINGTON AND
PITTSFIELD.

THE METEOROLOGICAL SUMMER FOR 2013 COMES IN AT THE 7TH WETTEST FOR
ALBANY SINCE 1826 AND THE 4TH WETTEST FOR POUGHKEEPSIE SINCE 1949.
THE AVERAGE TEMPERATURES FOR THE SUMMER WERE AROUND 1.5 DEGREES
ABOVE NORMAL FOR ALL 5 CLIMATE LOCATIONS.

PLEASE REFER TO OUR FACEBOOK POSTS OR TWEETS SUMMARIZING AUGUST 2013
AND THE SUMMER.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...WASULA
HYDROLOGY...SND/WASULA
CLIMATE...IAA








AREA FORECAST DISCUSSION

NWS ALBANY NY

 439 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A PERSISTENT WARM AND HUMID AIR MASS FOR THE FIRST DAY
OF SEPTEMBER WILL REMAIN OVER THE REGION THROUGH LABOR DAY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 435 AM EDT...THE MINI MCS THAT FORMED ALONG THE FRONTAL
BOUNDARY AND SOUTH OF THE WEAK WAVE OF LOW PRESSURE MOVING ALONG
IT HAS SHIFTED DOWN STREAM INTO SRN NEW ENGLAND. SOME DUAL POL QPE
VALUES OF 1 TO 3 INCHES OCCURRED OVER NW CT...SRN BERKS...AND THE
SRN TACONICS OF COLUMBIA AND EXTREME NE DUTCHES COUNTIES. THE KENX
RADAR AREA HAS BECOME QUIET WITH SUBSIDENCE IN THE WAKE OF THE
MCS. THE WATER VAPOR LOOP INDICATES LOTS OF MID AND UPPER LEVEL
DRY AIR HAS MOVED OVER UPSTATE NY AND PORTIONS OF WRN NEW ENGLAND.
THIS HAS ALLOWED PATCHY FOG AND SOME STRATUS TO FORM. CONDITIONS
REMAIN MUGGY FOR THE OPENING DAY OF SEPT.

THE MORNING SHOULD BEGIN DRY WITH LOTS OF CLOUDS FOR MOST OF THE
REGION. WEAK MID AND LOW LEVEL RIDGING WILL PROMOTE A QUIET START
OF THE DAY.  HOWEVER...THE DIFFUSE FRONTAL BOUNDARY WILL CREEP
NORTHWARD FROM THE SRN TIER. POP-UP SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO FORM...AND OTHER SHOWERS AND THUNDERSTORMS MAY
INITIATE ALONG THE HIGHER TERRAIN DUE TO THE DIFFERENTIAL HEATING
BTWN THE MTNS AND VALLEYS BY THE MID PM. THE COVERAGE AREA SHOULD
BE A LITTLE LESS THAN YESTERDAY. THE GENERAL TREND FROM THE LATEST
3-KM HRRR BASE REF PRODUCT IS FOR THE SHOWERS/THUNDERSTORMS TO
INCREASE FROM THE CAPITAL REGION SOUTHWARD BTWN 15Z-18Z. SOME OF
THE SHOWERS AND THUNDERSTORMS COULD DUMP HVY AMOUNTS OF RAINFALL
WITH PWATS STILL RUNNING 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL
/1.25-1.75 INCH RANGE/ FOR THE START OF METEOROLOGICAL SUMMER. THE
SBCAPE VALUES FROM BOTH THE GFS AND NAM ARE A BIT LOWER TODAY IN
THE 500-1000 J/KG WITH POCKETS GREATER THAN 1000 J/KG SOUTH OF THE
CAPITAL DISTRICT WHERE THE SFC DEWPTS WILL BE IN THE U60S TO L70S.
NOT ANTICIPATING ANY SEVERE WEATHER AGAIN WITH WEAK MID LEVEL
LAPSE RATES AND WEAK DEEP SHEAR PREVENTING ANY DEEP WELL ORGANIZED
CONVECTION.

ENHANCED WORDING WAS CONTINUED FOR HEAVY RAINFALL WITH ANY
CONVECTION TODAY. H850 TEMPS IN THE +15C TO +17C RANGE WITH SOME
SUNSHINE FOR A FEW HOURS WILL ALLOW TEMPS TO GET IN THE M70S TO
M80S ACROSS THE FCST AREA. THE NRN ZONES MAY ACTUALLY HAVE MORE
SUNSHINE TODAY...SINCE THE WEAK BOUNDARY WILL BE ACROSS THE SOUTH.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...A STRONG UPPER LEVEL LOW WILL BE CHURNING EASTWARD FROM
THE UPPER GREAT LAKES REGION AND ONTARIO. THE LARGE SFC TROUGH OF
LOW PRESSURE WILL BE MOVING TOWARDS THE NORTHEAST. ONE SHORT-WAVE
ASSOCIATED WITH THE SYSTEM IN THE SOUTHWEST FLOW ALOFT WILL IMPACT
THE REGION SHORTLY BEFORE OR JUST AFTER MIDNIGHT WITH SHOWERS AND
EMBEDDED THUNDERSTORMS...OR EVEN A DEVELOPING STRATIFORM RAIN
SHIELD. THE QG LIFT STRENGTHENS BTWN 06Z-12Z DUE TO THE
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION AND WEAK THERMAL
ADVECTION. THE RAIN INTENSIFIES DUE TO A PLUME OF UPPER LEVEL
DIVERGENCE MOVING OVER ERN NY. POPS WERE KEPT IN THE LIKELY OR
LOW-CATEGORICAL RANGE. MIN TEMPS WILL BE OF THE WET BULB VARIETY
IN THE M60S TO NEAR 70F WITH SOME L60S OVER THE MTNS.

LABOR DAY...THE LEAD SHORT-WAVE CROSSES THE REGION IN THE
MORNING/EARLY PM. THE RAINFALL COULD INCREASE IN INTENSITY AGAIN IN
THE EARLY TO MID PM...AS PORTIONS OF ERN NY WILL BE NEAR THE RIGHT
ENTRANCE REGION OF A 60-70 KT H250 JET STREAK. ALSO...SOME BREAKS
IN THE CLOUDS COULD ALLOW FOR ENOUGH DESTABILIZATION FOR SOME
STRONG TO POTENTIALLY SEVERE THUNDERSTORMS. THIS SET-UP IS STILL A
BIT NEBULOUS...BUT A STRONG COLD FRONT WILL BE APPROACHING IN THE
MID TO LATE PM. STRONG CONVERGENCE IS EXPECTED WITH THE BOUNDARY.
PLENTY OF LOW-LEVEL MOISTURE WILL BE IN PLACE WITH PWATS STILL A
COUPLE OF STD DEVS ABOVE NORMAL. SBCAPES VALUES MAY RANGE FROM
500-1500 J/KG WITH THE 0-6 KM BULK SHEAR VALUES RAMPING UP TO
25-35 KTS. THE SEE TEXT FROM SPC LOOKS FINE...BECAUSE THE SEVERE
POTENTIAL WILL BE CONDITIONAL TO THE AMOUNT OF SFC HEATING THAT
OCCURS...AND THE TIMING OF THESE IMPULSES ROTATING AROUND THE UPPER
LEVEL LOW. THE MID LEVEL LAPSE RATES STILL DON/T FALL TO 6.5 C/KM
OR LOWER UNTIL AFTER DARK. HEAVY RAINFALL LOOKS LIKE A GOOD BET
WITH A WIDESPREAD HALF AN INCH TO AN INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS TO 2 INCHES. WIDESPREAD FLASH FLOODING DOES NOT
LOOK LIKELY AT THIS TIME...BUT THE POSSIBILITY WILL CONTINUE TO BE
MONITORED.

OUR FORECAST REFLECTS MAX TEMPS CLOSER TO THE COOLER NAM MOS
VALUES FOR THE HOLIDAY WITH U70S TO L80S IN THE VALLEYS...AND
U60S TO M70S OVER THE HIGH PEAKS.

MON NIGHT...THE SHOWERS AND THUNDERSTORMS WILL END WITH THE
PASSAGE OF THE FIRST COLD FRONT. THE BETTER COLD ADVECTION DOES
NOT ARRIVE UNTIL AFTER DAY BREAK. LOWS WILL RANGE FROM THE MID AND
U50S OVER THE NW ZONES TO LOWER TO M60S OVER THE SE ZONES.

TUE-TUE NIGHT...MUCH COOLER AIR INVADES THE FCST AREA...AS THE
HUMIDITY BREAKS. THE UPPER LEVEL TROUGH AXIS...AND A SECONDARY
COLD FRONT MOVE THROUGH DURING THE DAY WITH ISOLD-SCT SHOWERS
POSSIBLE BASED ON THE NAM/GFS/ECMWF/CANADIAN GUIDANCE. H850 TEMPS
FALL TO AROUND +10C NEAR THE CAPITAL REGION. THE COLD POOL WILL
HELP FOCUS INSTABILITY SHOWERS. MAX TEMPS WILL BE IN THE MID 70S
TO L80S IN THE VALLEYS...WITH M60S TO M70S OVER THE MTNS. LOWS
WILL COOL OFF INTO THE 50S FOR MOST OF THE REGION TUE NIGHT...WITH
SOME U40S OVER THE MTNS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE NORTHEAST WILL
REMAIN UNDER A LONGWAVE TROUGH FOR THE PERIOD.

WE ARE LOOKING FOR PLEASANT DAY WEDNESDAY AS HIGHER PRESSURE BUILDS
IN WITH SEASONABLY WARM TEMPERATURES. A COLD FRONT IS FORECAST TO
MOVE ACROSS THE REGION WEDNESDAY NIGHT INTO THURSDAY USHERING IN A
MORE AUTUMN-LIKE AIRMASS AS CANADIAN HIGH PRESSURE BUILDS IN ITS
WAKE. AN INCREASE CLOUDS ALONG WITH ISOLATED SHOWERS SHOULD ACCOMPANY
THE BOUNDARY. TEMPERATURES THURSDAY AND FRIDAY SHOULD RUN ABOUT 5
DEGREES BELOW NORMAL.

TEMPERATURES ARE ANTICIPATED TO MODERATE BACK TO SEASONABLE LEVELS
FOR THE START OF THE WEEKEND AS THE SURFACE HIGH SHIFTS TO OUR
SOUTHEAST ALLOWING A SOUTH-SOUTHWEST FLOW TO DEVELOP.
HOWEVER...THERE ARE MODEL DIFFERENCES DEALING WITH THE TIMING AND
STRENGTH OF INDIVIDUALS SHORT WAVE ROTATING ABOUT AN UPPER LOW
OVER EASTERN CANADA. THIS WILL IMPACT THE TIMING OF FRONTAL
BOUNDARIES ACROSS THE REGION NEXT WEEKEND. AT THIS TIME...IT APPEARS
A WARM FRONT SHOULD MOVE INTO/THROUGH THE REGION ON SATURDAY AS A LOW
PASSES TO OUR NORTH.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
A MUGGY AIRMASS IS IN PLACE WITH A STALLED BOUNDARY ACROSS REGION
WITH THE MORE UNSTABLE AIR LOCATED TO THE SOUTH AND EAST OF THE
BOUNDARY. THE RADAR IS QUIET ACROSS THE FORECAST AREA AT THIS TIME
AND A LULL IN THE CONVECTION IS EXPECTED ACROSS THE LOCAL AREA INTO
THIS AFTERNOON. GUIDANCE INDICATES THE FRONTAL BOUNDARY WILL WEAKEN
AND DISSIPATE. CHANCES FOR CONVECTION WILL INCREASE MID TO LATE
AFTERNOON AND ESPECIALLY TONIGHT AS A STRONGER SHORT WAVE APPROACHES
WITH HEIGHT FALLS OCCURRING ACROSS THE REGION.

MVFR TO LIFR CONDITIONS EXPECTED THROUGH THE EARLY MORNING HOURS DUE
TO FOG AND CIGS. CONDITIONS WILL IMPROVE TO VFR BY MID/LATE MORNING.
VFR CONDITIONS ARE THEN EXPECTED THROUGH MUCH OF THE DAY WITH
CONDITIONS LOWERING AS WE HEAD THROUGH THE EVENING AND CHANCES FOR
SHOWERS AND THUNDERSTORMS INCREASES.

A LIGHT SOUTH-SOUTHWEST FLOW IS EXPECTED TO DEVELOP DURING THE DAY
SUNDAY WITH LIGHT AND VARIABLE TO CALM WINDS EXPECTED AGAIN SUNDAY
NIGHT.

OUTLOOK...
MON NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUE: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
TUE-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED THE NEXT SEVERAL DAYS. A HUMID
AIR MASS WITH SEVERAL CHANCES OF RAINFALL WILL BE POSSIBLE INTO
TUESDAY.

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL FORM ALONG A
WEAK BOUNDARY TODAY.  THE UNSETTLED WEATHER CONTINUES TONIGHT INTO
LABOR DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS TO EASTERN NEW YORK AND WESTERN
NEW ENGLAND WITH SOME LOCALLY HEAVY RAINFALL.

HIGH RH VALUES OF 55 TO 75 PERCENT WILL OCCUR THIS AFTERNOON. THE
RH VALUES WILL RECOVER CLOSE TO 100 PERCENT MONDAY MORNING...AND
REMAIN HIGH IN THE AFTERNOON AT 65 TO 85 PERCENT.

EXPECT WINDS FROM THE SOUTHEAST OR SOUTH AT 5 TO 15 MPH TODAY.
LIGHT AND VARIABLE WINDS WILL OCCUR TONIGHT. SOUTH OR SOUTHWEST WINDS
OF 5 TO 15 MPH ARE FORECAST FOR LABOR DAY.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED OR ISOLATED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR
WIDESPREAD RAINFALL WILL BE TONIGHT AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. SOME LOCATIONS COULD GET A QUICK FEW
INCHES OF RAINFALL IN 3 HOURS OR LESS...AS WHAT OCCURRED ON
SATURDAY AND THIS MORNING.

ISOLATED URBAN...SMALL STREAM...AND POOR DRAINAGE FLOODING WILL BE
POSSIBLE THE REMAINDER OF THE HOLIDAY WEEKEND. SOME SUBSTANTIAL WITHIN
BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE SHOWERS AND STORMS
OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS TIME FRAME.

HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW MOVING
THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING TODAY INTO LABOR
DAY. IF THE POTENTIAL FOR WIDESPREAD FLASH FLOODING
INCREASES...THEN A FLASH FLOOD WATCH MAY BE NEEDED FOR PARTS OF
THE HYDRO SERVICE AREA TONIGHT INTO LABOR DAY.

RAINFALL AMOUNTS WILL CONTINUE TO BE QUITE VARIABLE DUE TO WHERE
THE CONVECTION DEVELOPS AND MOVES. SOME LOCATIONS RECEIVED 1 TO 3
INCHES OF RAINFALL YESTERDAY INTO THIS MORNING /SRN TACONICS...NW
CT...SRN BERKSHIRES...HELDERBERGS AND PORTIONS OF ALY CTY/. THE
SOILS ARE BIT MORE SATURATED IN THESE AREAS...AND THEY WILL HAVE
TO MONITORED FOR ANY HYDRO ISSUES.

COOLER AND DRIER WEATHER WILL MOVE BACK INTO THE HSA FOR THE MID
WEEK ALLOWING STREAMS AND RIVERS TO RECEDE FROM THE RAINFALL.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA
FIRE WEATHER...WASULA
HYDROLOGY...SND/WASULA








AREA FORECAST DISCUSSION

NWS ALBANY NY

 153 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER EASTERN NEW
YORK AND WESTERN NEW ENGLAND THROUGH THE HOLIDAY WEEKEND.  A WEAK
DISTURBANCE WILL PRODUCE SHOWERS AND THUNDERSTORMS THIS MORNING WELL
SOUTH AND EAST OF THE CAPITAL DISTRICT WITH SOME LOCALLY HEAVY
RAINFALL.  THE UNSETTLED WEATHER CONTINUES LATE SUNDAY INTO LABOR
DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS TO THE REGION.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 122 AM EDT...A CLUSTER OF STRONG THUNDERSTORMS DEVELOPED OVER
THE MID HUDSON VALLEY...SRN TACONICS...NW CT AND SRN BERKSHIRES
AHEAD OF A SFC TROUGH...AND A PASSING WEAK WAVE OF LOW
PRESSURE OVER THE PAST FEW HOURS. THE LATEST SPC MESO PAGE SHOWED A
RESPECTABLE INSTABILITY AXIS OF 1000-1500 J/KG WHICH THIS LIFTING
MECHANISM TAPPED INTO. NARROW 50 DBZ REF CORES HAVE REACHED 25-30
KFT AGL OCCASIONALLY WITH SOME VERY HVY RAINFALL...AS PWATS IN
THIS CORRIDOR ARE IN THE 1.50 TO 1.90 INCH RANGE. THE POPS HAVE
BEEN RAISED TO HIGH CHC AND LIKELY IN THESE AREAS FOR ANOTHER HOUR
OR TWO...AND THIS CLUSTER WILL PASS EAST INTO THE CT RIVER VALLEY
AND SRN NEW ENGLAND. SEVERAL SPS STATEMENTS HAVE BEEN USED TO
ADDRESS THIS CLUSTER OF THUNDERSTORMS...AS WELL AS A FEW FLOOD
ADVISORIES WHERE A QUICK COUPLE OF INCHES HAVE OCCURRED IN A FEW
SPOTS.

THE LATEST 3KM HRRR FINALLY CAUGHT ONTO THIS CONVECTION...AND DOES
HAVE IT DIMINISHING BY 07Z OR SO. THE POPS HAVE BEEN REDUCED TO
SLIGHT CHC OR NOTHING FURTHER NORTH AND WEST OF THE ONGOING
CONVECTION. A FEW SHOWERS/SPRINKLES HAVE POPPED UP IN RENSSELAER
COUNTY AS OF 05Z.

PATCHY FOG HAS BEEN ADDED TO THE FCST AREA WITH THE WATER VAPOR
LOOP SHOWING NOTABLE DRYING ALOFT WITH THE PASSAGE OF THE SFC
TROUGH AND MID LEVEL SHORT-WAVE. LOWS TEMPS WILL BE ON THE BALMY
SIDE IN THE HUMID AIR MASS...WITH WIDESPREAD 60S TO L70S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH BY MIDNIGHT. SOME
CLEARING OVER WESTERN NY NOW SHOWING UP ON SATELLITE SHOULD WORK
ITS WAY EAST AND LEAD TO PATCHY CLOUDS LATE TONIGHT. SOME DENSE
FOG LIKELY WHERE CLOUDS BREAK AS AIRMASS IS VERY MOIST AND NIGHTS
ARE GETTING LONGER. FOR SUNDAY...CLOUDS AND FOG EXPECTED DURING
THE MORNING...BUT WEAK RIDGING ALOFT SHOULD PROVIDE FOR SOME
SUBSIDENCE AND BREAKS IN THE CLOUDS. NO STRONG TRIGGER FOR
THUNDERSTORMS ON SUNDAY...BUT WITH WARM HUMID AIRMASS IN
PLACE...THERE IS A CHANCE OF AFTERNOON POP UP SHOWERS AND
THUNDERSTORMS. FOR SUNDAY NIGHT...MODELS INDICATE A STRONG SHORTWAVE
WILL ROTATE AROUND THE UPPER LEVEL LOW OVER THE UPPER GREAT LAKES.
THIS SHORTWAVE WILL CROSS THE ALBANY FORECAST AREA LATE SUNDAY NIGHT
AND MONDAY MORNING. DYNAMICS LOOK STRONG WITH THIS FEATURE AND WITH
MOIST UNSTABLE AIRMASS IN PLACE SHOWERS AND STORMS CAN BE EXPECTED.
THERE MAY BE A LULL DURING THE MIDDLE OF THE DAY ON MONDAY BEFORE
THE COLD FRONT APPROACHES FROM THE WEST LATER IN THE DAY PROVIDING
LIFT FOR ANOTHER ROUND OF SHOWERS AND STORMS. AT THIS
TIME...RAINFALL FROM THESE SYSTEMS DOES NOT LOOK EXCESSIVE WITH A
WIDESPREAD 1-2 INCHES POSSIBLE. HOWEVER...WITH THE MOIST AIRMASS
OVERHEAD...LOCALIZED HEAVY DOWNPOURS ARE POSSIBLE.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODEL AGREEMENT FOR OUR PART OF THE COUNTRY IS EXCELLENT THROUGH
THE LONG TERM PERIOD. OVERALL...A LONG WAVE TROUGH IS EXPECTED IN
THE EASTERN UNITED STATES LEADING TO TEMPERATURES AVERAGING NEAR TO
SLIGHTLY BELOW NORMAL.

FOR TUESDAY...THE LOW PRESSURE SYSTEM THAT BROUGHT UNSETTLED
WEATHER ON LABOR DAY...WILL BE OVER EASTERN CANADA WITH A COLD
FRONT ALONG THE EASTERN SEABOARD. UPPER LEVEL TROUGH EXTENDS SOUTH
ALONG THE SPINE OF THE APPALACHIANS. MODELS ARE IN GOOD AGREEMENT
THAT CLOUDS AND AND A FEW SHOWERS MAY LINGER ON TUESDAY. HIGHEST
POPS SOUTHEAST OF ALBANY CLOSER TO DEPARTING COLD FRONT.
WEDNESDAY...HIGH PRESSURE RIDGES IN FROM THE OHIO VALLEY WITH FAIR
WEATHER EXPECTED. A COLD FRONT LOOKS TO PUSH THROUGH THE AREA
WEDNESDAY NIGHT AND THURSDAY MORNING...BUT MOISTURE LOOKS LIMITED
SO ONLY CHANCE POPS FOR RAIN SHOWERS LATER WEDNESDAY NIGHT INTO
THURSDAY. COOL BREEZY CONDITIONS EXPECTED ON THURSDAY. BY
FRIDAY...HIGH PRESSURE RIDGES IN THE MID ATLANTIC REGION WITH FAIR
WEATHER AND A SOUTHWEST FLOW OF AIR AND MODERATING TEMPERATURES.
ON SATURDAY...YET ANOTHER REINFORCING SHOT OF COOLER AIR LOOK TO
PUSH INTO THE ALBANY FORECAST AREA. CHANCE POPS FOR RAIN SHOWERS
ON SATURDAY WITH THE FRONTAL PASSAGE.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
A MUGGY AIRMASS IS IN PLACE WITH A STALLED BOUNDARY ACROSS REGION
WITH THE MORE UNSTABLE AIR LOCATED TO THE SOUTH AND EAST OF THE
BOUNDARY. A CLUSTER OF SHOWERS AND THUNDERSTORMS BETWEEN KPSF AND
KPOU WILL CONTINUE TO MOVE EASTWARD IN ASSOCIATION WITH A SHORT WAVE
TROUGH WITH ADDITIONAL SCATTERED CONVECTION DEVELOPING JUST TO THE
NORTH WHICH WILL IMPACT KPSF. ONCE THE SHORT WAVE TROUGH MOVES OFF
TO THE EAST EXPECTING A LULL IN THE CONVECTION WELL INTO THIS
AFTERNOON. GUIDANCE INDICATES THE BOUNDARY WILL WEAKEN AND DISSIPATE
OVER THE AREA. CHANCES FOR CONVECTION WILL INCREASE MID/LATE THIS
AFTERNOON AND ESPECIALLY THIS EVENING AS A STRONGER SHORT WAVE
APPROACHES CAUSING HEIGHT FALLS ACROSS THE REGION.

MVFR/IFR CONDITIONS EXPECTED THROUGH THE EARLY MORNING HOURS DUE TO
FOG AND CIGS WITH AN IMPROVEMENT BY LATE MORNING. VFR CONDITIONS
ARE THEN EXPECTED THROUGH MUCH OF THE DAY WITH CONDITIONS LOWERING
TO MVFR AS WE HEAD THROUGH THE EVENING AND CHANCES FOR SHOWERS AND
THUNDERSTORMS INCREASES.

A LIGHT SOUTH-SOUTHWEST FLOW IS EXPECTED TO DEVELOP DURING THE DAY
WITH LIGHT AND VARIABLE TO CALM WINDS EXPECTED AGAIN TONIGHT.

OUTLOOK...
TUE: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
TUE NIGHT-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE EXPECTED IN THE HUMID AIR MASS WITH
SEVERAL CHANCES OF RAINFALL.

THE BEST CHANCES FOR WIDESPREAD RAINFALL ARE SATURDAY AFTERNOON
AND EVENING AND AGAIN ON LABOR DAY. A WEAK SURFACE FRONT WILL
CROSS THE AREA THIS AFTERNOON AND EVENING WITH NUMEROUS SHOWERS
AND STORMS. SOME CLEARING BEHIND THE FRONT WILL LEAD TO FOG AND
CLOUDS SUNDAY MORNING. PARTIAL CLEARING IS EXPECTED SUNDAY
AFTERNOON WITH ISOLATED POP UP SHOWERS AND THUNDERSTORMS EXPECTED
IN THE STEAMY AIRMASS. A STRONGER LOW PRESSURE SYSTEM WILL BRING
ANOTHER CHANCE FOR WIDESPREAD SHOWERS AND STORMS SUNDAY NIGHT AND
MONDAY.

THE RH VALUES RECOVER TO CLOSE TO 100 PERCENT SUNDAY MORNING.
HIGH RH VALUES OF 60 TO 75 PERCENT WILL OCCUR SUNDAY AFTERNOON. RH
VALUES NEAR 100 PERCENT ARE FORECAST AGAIN MONDAY MORNING.

THE WINDS WILL BE FROM THE SOUTH TO SOUTHWEST AT AROUND 5 MPH
TONIGHT. TOMORROW...EXPECT WINDS FROM THE SOUTHEAST AT 10 TO 20
MPH. SOUTHEAST WINDS OF 5 TO 10 MPH ARE FORECAST FOR SUNDAY NIGHT.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR WIDESPREAD
RAINFALL WILL BE TODAY AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. ISOLATED URBAN...SMALL STREAM...AND
POOR DRAINAGE FLOODING WILL BE POSSIBLE THIS WEEKEND. SOME
MODERATE WITHIN BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE
SHOWERS AND STORMS OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS
TIME FRAME. HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW
MOVING THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING DURING THE
WEEKEND.

RAINFALL AMOUNTS WILL BE QUITE VARIABLE DUE TO THE SHOWERY NATURE
OF THE RAIN.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...SND/WASULA
NEAR TERM...HWJIV/WASULA
SHORT TERM...SND
LONG TERM...SND
AVIATION...IAA
FIRE WEATHER...SND
HYDROLOGY...SND/WASULA











AREA FORECAST DISCUSSION

NWS ALBANY NY

 140 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER EASTERN NEW
YORK AND WESTERN NEW ENGLAND THROUGH THE HOLIDAY WEEKEND.  A WEAK
DISTURBANCE WILL PRODUCE SHOWERS AND THUNDERSTORMS THIS MORNING WELL
SOUTH AND EAST OF THE CAPITAL DISTRICT WITH SOME LOCALLY HEAVY
RAINFALL.  THE UNSETTLED WEATHER CONTINUES LATE SUNDAY INTO LABOR
DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS TO THE REGION.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 122 AM EDT...A CLUSTER OF STRONG THUNDERSTORMS DEVELOPED OVER
THE MID HUDSON VALLEY...SRN TACONICS...NW CT AND SRN BERKSHIRES
AHEAD OF A SFC TROUGH...AND A PASSING WEAK WAVE OF LOW
PRESSURE OVER THE PAST FEW HOURS. THE LATEST SPC MESO PAGE SHOWED A
RESPECTABLE INSTABILITY AXIS OF 1000-1500 J/KG WHICH THIS LIFTING
MECHANISM TAPPED INTO. NARROW 50 DBZ REF CORES HAVE REACHED 25-30
KFT AGL OCCASIONALLY WITH SOME VERY HVY RAINFALL...AS PWATS IN
THIS CORRIDOR ARE IN THE 1.50 TO 1.90 INCH RANGE. THE POPS HAVE
BEEN RAISED TO HIGH CHC AND LIKELY IN THESE AREAS FOR ANOTHER HOUR
OR TWO...AND THIS CLUSTER WILL PASS EAST INTO THE CT RIVER VALLEY
AND SRN NEW ENGLAND. SEVERAL SPS STATEMENTS HAVE BEEN USED TO
ADDRESS THIS CLUSTER OF THUNDERSTORMS...AS WELL AS A FEW FLOOD
ADVISORIES WHERE A QUICK COUPLE OF INCHES HAVE OCCURRED IN A FEW
SPOTS.

THE LATEST 3KM HRRR FINALLY CAUGHT ONTO THIS CONVECTION...AND DOES
HAVE IT DIMINISHING BY 07Z OR SO. THE POPS HAVE BEEN REDUCED TO
SLIGHT CHC OR NOTHING FURTHER NORTH AND WEST OF THE ONGOING CONVECTION.
A FEW SHOWERS/SPRINKLES HAVE POPPED UP IN RENSSELAER COUNTY AS OF
05Z.

PATCHY FOG HAS BEEN ADDED TO THE FCST AREA WITH THE WATER VAPOR
LOOP SHOWING NOTABLE DRYING ALOFT WITH THE PASSAGE OF THE SFC
TROUGH AND MID LEVEL SHORT-WAVE. LOWS TEMPS WILL BE ON THE BALMY
SIDE IN THE HUMID AIR MASS...WITH WIDESPREAD 60S TO L70S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH BY MIDNIGHT. SOME
CLEARING OVER WESTERN NY NOW SHOWING UP ON SATELLITE SHOULD WORK
ITS WAY EAST AND LEAD TO PATCHY CLOUDS LATE TONIGHT. SOME DENSE
FOG LIKELY WHERE CLOUDS BREAK AS AIRMASS IS VERY MOIST AND NIGHTS
ARE GETTING LONGER. FOR SUNDAY...CLOUDS AND FOG EXPECTED DURING
THE MORNING...BUT WEAK RIDGING ALOFT SHOULD PROVIDE FOR SOME
SUBSIDENCE AND BREAKS IN THE CLOUDS. NO STRONG TRIGGER FOR
THUNDERSTORMS ON SUNDAY...BUT WITH WARM HUMID AIRMASS IN
PLACE...THERE IS A CHANCE OF AFTERNOON POP UP SHOWERS AND
THUNDERSTORMS. FOR SUNDAY NIGHT...MODELS INDICATE A STRONG SHORTWAVE
WILL ROTATE AROUND THE UPPER LEVEL LOW OVER THE UPPER GREAT LAKES.
THIS SHORTWAVE WILL CROSS THE ALBANY FORECAST AREA LATE SUNDAY NIGHT
AND MONDAY MORNING. DYNAMICS LOOK STRONG WITH THIS FEATURE AND WITH
MOIST UNSTABLE AIRMASS IN PLACE SHOWERS AND STORMS CAN BE EXPECTED.
THERE MAY BE A LULL DURING THE MIDDLE OF THE DAY ON MONDAY BEFORE
THE COLD FRONT APPROACHES FROM THE WEST LATER IN THE DAY PROVIDING
LIFT FOR ANOTHER ROUND OF SHOWERS AND STORMS. AT THIS
TIME...RAINFALL FROM THESE SYSTEMS DOES NOT LOOK EXCESSIVE WITH A
WIDESPREAD 1-2 INCHES POSSIBLE. HOWEVER...WITH THE MOIST AIRMASS
OVERHEAD...LOCALIZED HEAVY DOWNPOURS ARE POSSIBLE.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODEL AGREEMENT FOR OUR PART OF THE COUNTRY IS EXCELLENT THROUGH
THE LONG TERM PERIOD. OVERALL...A LONG WAVE TROUGH IS EXPECTED IN
THE EASTERN UNITED STATES LEADING TO TEMPERATURES AVERAGING NEAR TO
SLIGHTLY BELOW NORMAL.

FOR TUESDAY...THE LOW PRESSURE SYSTEM THAT BROUGHT UNSETTLED
WEATHER ON LABOR DAY...WILL BE OVER EASTERN CANADA WITH A COLD
FRONT ALONG THE EASTERN SEABOARD. UPPER LEVEL TROUGH EXTENDS SOUTH
ALONG THE SPINE OF THE APPALACHIANS. MODELS ARE IN GOOD AGREEMENT
THAT CLOUDS AND AND A FEW SHOWERS MAY LINGER ON TUESDAY. HIGHEST
POPS SOUTHEAST OF ALBANY CLOSER TO DEPARTING COLD FRONT.
WEDNESDAY...HIGH PRESSURE RIDGES IN FROM THE OHIO VALLEY WITH FAIR
WEATHER EXPECTED. A COLD FRONT LOOKS TO PUSH THROUGH THE AREA
WEDNESDAY NIGHT AND THURSDAY MORNING...BUT MOISTURE LOOKS LIMITED
SO ONLY CHANCE POPS FOR RAIN SHOWERS LATER WEDNESDAY NIGHT INTO
THURSDAY. COOL BREEZY CONDITIONS EXPECTED ON THURSDAY. BY
FRIDAY...HIGH PRESSURE RIDGES IN THE MID ATLANTIC REGION WITH FAIR
WEATHER AND A SOUTHWEST FLOW OF AIR AND MODERATING TEMPERATURES.
ON SATURDAY...YET ANOTHER REINFORCING SHOT OF COOLER AIR LOOK TO
PUSH INTO THE ALBANY FORECAST AREA. CHANCE POPS FOR RAIN SHOWERS
ON SATURDAY WITH THE FRONTAL PASSAGE.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
A MUGGY AIRMASS IS IN PLACE WITH A STALLED BOUNDARY ACROSS REGION
WITH THE MORE UNSTABLE AIR LOCATED TO THE SOUTH AND EAST OF THE
BOUNDARY. A CLUSTER OF SHOWERS AND THUNDERSTORMS BETWEEN KPSF AND
KPOU WILL CONTINUE TO MOVE EASTWARD IN ASSOCIATION WITH A SHORT WAVE
TROUGH. ONCE THE SHORT WAVE TROUGH MOVES OFF TO THE EAST EXPECTING
A LULL IN THE CONVECTION WELL INTO THIS AFTERNOON. GUIDANCE INDICATES
THE BOUNDARY WILL WEAKEN AND DISSIPATE OVER THE AREA. CHANCES FOR
CONVECTION WILL INCREASE MID/LATE THIS AFTERNOON AND ESPECIALLY
THIS EVENING AS A STRONGER SHORT WAVE APPROACHES CAUSING HEIGHT
FALLS ACROSS THE REGION.

MVFR/IFR CONDITIONS EXPECTED THROUGH THE EARLY MORNING HOURS DUE TO
FOG AND CIGS WITH AN IMPROVEMENT BY LATE MORNING. VFR CONDITIONS
ARE THEN EXPECTED THROUGH MUCH OF THE DAY WITH CONDITIONS LOWERING
TO MVFR AS WE HEAD THROUGH THE EVENING AND CHANCES FOR SHOWERS AND
THUNDERSTORMS INCREASES.

A LIGHT SOUTH-SOUTHWEST FLOW IS EXPECTED TO DEVELOP DURING THE DAY
WITH LIGHT AND VARIABLE TO CALM WINDS EXPECTED AGAIN TONIGHT.

OUTLOOK...
TUE: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
TUE NIGHT-WED: NO OPERATIONAL IMPACT.  NO SIG WX.
WED NIGHT-THU: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE EXPECTED IN THE HUMID AIR MASS WITH
SEVERAL CHANCES OF RAINFALL.

THE BEST CHANCES FOR WIDESPREAD RAINFALL ARE SATURDAY AFTERNOON
AND EVENING AND AGAIN ON LABOR DAY. A WEAK SURFACE FRONT WILL
CROSS THE AREA THIS AFTERNOON AND EVENING WITH NUMEROUS SHOWERS
AND STORMS. SOME CLEARING BEHIND THE FRONT WILL LEAD TO FOG AND
CLOUDS SUNDAY MORNING. PARTIAL CLEARING IS EXPECTED SUNDAY
AFTERNOON WITH ISOLATED POP UP SHOWERS AND THUNDERSTORMS EXPECTED
IN THE STEAMY AIRMASS. A STRONGER LOW PRESSURE SYSTEM WILL BRING
ANOTHER CHANCE FOR WIDESPREAD SHOWERS AND STORMS SUNDAY NIGHT AND
MONDAY.

THE RH VALUES RECOVER TO CLOSE TO 100 PERCENT SUNDAY MORNING.
HIGH RH VALUES OF 60 TO 75 PERCENT WILL OCCUR SUNDAY AFTERNOON. RH
VALUES NEAR 100 PERCENT ARE FORECAST AGAIN MONDAY MORNING.

THE WINDS WILL BE FROM THE SOUTH TO SOUTHWEST AT AROUND 5 MPH
TONIGHT. TOMORROW...EXPECT WINDS FROM THE SOUTHEAST AT 10 TO 20
MPH. SOUTHEAST WINDS OF 5 TO 10 MPH ARE FORECAST FOR SUNDAY NIGHT.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR WIDESPREAD
RAINFALL WILL BE TODAY AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. ISOLATED URBAN...SMALL STREAM...AND
POOR DRAINAGE FLOODING WILL BE POSSIBLE THIS WEEKEND. SOME
MODERATE WITHIN BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE
SHOWERS AND STORMS OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS
TIME FRAME. HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW
MOVING THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING DURING THE
WEEKEND.

RAINFALL AMOUNTS WILL BE QUITE VARIABLE DUE TO THE SHOWERY NATURE
OF THE RAIN.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$
SYNOPSIS...SND/WASULA
NEAR TERM...HWJIV/WASULA
SHORT TERM...SND
LONG TERM...SND
AVIATION...IAA
FIRE WEATHER...SND
HYDROLOGY...SND/WASULA








AREA FORECAST DISCUSSION

NWS ALBANY NY

 124 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER EASTERN NEW
YORK AND WESTERN NEW ENGLAND THROUGH THE HOLIDAY WEEKEND.  A WEAK
DISTURBANCE WILL PRODUCE SHOWERS AND THUNDERSTORMS THIS MORNING WELL
SOUTH AND EAST OF THE CAPITAL DISTRICT WITH SOME LOCALLY HEAVY
RAINFALL.  THE UNSETTLED WEATHER CONTINUES LATE SUNDAY INTO LABOR
DAY WHEN A STRONG UPPER LEVEL LOW BRINGS MORE WIDESPREAD SHOWERS AND
SCATTERED THUNDERSTORMS TO THE REGION.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 122 AM EDT...A CLUSTER OF STRONG THUNDERSTORMS DEVELOPED OVER
THE MID HUDSON VALLEY...SRN TACONICS...NW CT AND SRN BERKSHIRES
AHEAD OF A SFC TROUGH...AND A PASSING WEAK WAVE OF LOW
PRESSUREOVER THE PAST FEW HOURS. THE LATEST SPC MESO PAGE SHOWED A
RESPECTABLE INSTABILITY AXIS OF 1000-1500 J/KG WHICH THIS LIFTING
MECHANISM TAPPED INTO. NARROW 50 DBZ REF CORES HAVE REACHED 25-30
KFT AGL OCCASIONALLY WITH SOME VERY HVY RAINFALL...AS PWATS IN
THIS CORRIDOR ARE IN THE 1.50 TO 1.90 INCH RANGE. THE POPS HAVE
BEEN RAISED TO HIGH CHC AND LIKELY IN THESE AREAS FOR ANOTHER HOUR
OR TWO...AND THIS CLUSTER WILL PASS EAST INTO THE CT RIVER VALLEY
AND SRN NEW ENGLAND. SEVERAL SPS STATEMENTS HAVE BEEN USED TO
ADDRESS THIS CLUSTER OF THUNDERSTORMS...AS WELL AS A FEW FLOOD
ADVISORIES WHERE A QUICK COUPLE OF INCHES HAVE OCCURRED IN A FEW
SPOTS.

THE LATEST 3KM HRRR FINALLY CAUGHT ONTO THIS CONVECTION...AND DOES
HAVE IT DIMINISHING BY 07Z OR SO. THE POPS HAVE BEEN REDUCED TO
SLIGHT CHC OR NOTHING FURTHER NORTH AND WEST OF THE ONGOING CONVECTION.
A FEW SHOWERS/SPRINKLES HAVE POPPED UP IN RENSSELAER COUNTY AS OF
05Z.

PATCHY FOG HAS BEEN ADDED TO THE FCST AREA WITH THE WATER VAPOR
LOOP SHOWING NOTABLE DRYING ALOFT WITH THE PASSAGE OF THE SFC
TROUGH AND MID LEVEL SHORT-WAVE. LOWS TEMPS WILL BE ON THE BALMY
SIDE IN THE HUMID AIR MASS...WITH WIDESPREAD 60S TO L70S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY NIGHT/...
SHOWERS AND THUNDERSTORMS SHOULD DIMINISH BY MIDNIGHT. SOME
CLEARING OVER WESTERN NY NOW SHOWING UP ON SATELLITE SHOULD WORK
ITS WAY EAST AND LEAD TO PATCHY CLOUDS LATE TONIGHT. SOME DENSE
FOG LIKELY WHERE CLOUDS BREAK AS AIRMASS IS VERY MOIST AND NIGHTS
ARE GETTING LONGER. FOR SUNDAY...CLOUDS AND FOG EXPECTED DURING
THE MORNING...BUT WEAK RIDGING ALOFT SHOULD PROVIDE FOR SOME
SUBSIDENCE AND BREAKS IN THE CLOUDS. NO STRONG TRIGGER FOR
THUNDERSTORMS ON SUNDAY...BUT WITH WARM HUMID AIRMASS IN
PLACE...THERE IS A CHANCE OF AFTERNOON POP UP SHOWERS AND
THUNDERSTORMS. FOR SUNDAY NIGHT...MODELS INDICATE A STRONG SHORTWAVE
WILL ROTATE AROUND THE UPPER LEVEL LOW OVER THE UPPER GREAT LAKES.
THIS SHORTWAVE WILL CROSS THE ALBANY FORECAST AREA LATE SUNDAY NIGHT
AND MONDAY MORNING. DYNAMICS LOOK STRONG WITH THIS FEATURE AND WITH
MOIST UNSTABLE AIRMASS IN PLACE SHOWERS AND STORMS CAN BE EXPECTED.
THERE MAY BE A LULL DURING THE MIDDLE OF THE DAY ON MONDAY BEFORE
THE COLD FRONT APPROACHES FROM THE WEST LATER IN THE DAY PROVIDING
LIFT FOR ANOTHER ROUND OF SHOWERS AND STORMS. AT THIS
TIME...RAINFALL FROM THESE SYSTEMS DOES NOT LOOK EXCESSIVE WITH A
WIDESPREAD 1-2 INCHES POSSIBLE. HOWEVER...WITH THE MOIST AIRMASS
OVERHEAD...LOCALIZED HEAVY DOWNPOURS ARE POSSIBLE.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
MODEL AGREEMENT FOR OUR PART OF THE COUNTRY IS EXCELLENT THROUGH
THE LONG TERM PERIOD. OVERALL...A LONG WAVE TROUGH IS EXPECTED IN
THE EASTERN UNITED STATES LEADING TO TEMPERATURES AVERAGING NEAR TO
SLIGHTLY BELOW NORMAL.

FOR TUESDAY...THE LOW PRESSURE SYSTEM THAT BROUGHT UNSETTLED
WEATHER ON LABOR DAY...WILL BE OVER EASTERN CANADA WITH A COLD
FRONT ALONG THE EASTERN SEABOARD. UPPER LEVEL TROUGH EXTENDS SOUTH
ALONG THE SPINE OF THE APPALACHIANS. MODELS ARE IN GOOD AGREEMENT
THAT CLOUDS AND AND A FEW SHOWERS MAY LINGER ON TUESDAY. HIGHEST
POPS SOUTHEAST OF ALBANY CLOSER TO DEPARTING COLD FRONT.
WEDNESDAY...HIGH PRESSURE RIDGES IN FROM THE OHIO VALLEY WITH FAIR
WEATHER EXPECTED. A COLD FRONT LOOKS TO PUSH THROUGH THE AREA
WEDNESDAY NIGHT AND THURSDAY MORNING...BUT MOISTURE LOOKS LIMITED
SO ONLY CHANCE POPS FOR RAIN SHOWERS LATER WEDNESDAY NIGHT INTO
THURSDAY. COOL BREEZY CONDITIONS EXPECTED ON THURSDAY. BY
FRIDAY...HIGH PRESSURE RIDGES IN THE MID ATLANTIC REGION WITH FAIR
WEATHER AND A SOUTHWEST FLOW OF AIR AND MODERATING TEMPERATURES.
ON SATURDAY...YET ANOTHER REINFORCING SHOT OF COOLER AIR LOOK TO
PUSH INTO THE ALBANY FORECAST AREA. CHANCE POPS FOR RAIN SHOWERS
ON SATURDAY WITH THE FRONTAL PASSAGE.

&&

.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
AS OF 1015 PM EDT...A FEW MORE SHOWERS AND THUNDERSTORMS HAVE POPPED
UP NEAR THE POUGHKEEPSIE AREA. OTHERWISE...THE CONVECTION HAS PRETTY
MUCH WEATHER DOWN. PLACED A VCTS FOR AN HOUR OR SO THERE ALONG WITH
AN HOUR LONG TEMPO FOR MVFR THUNDERSTORM THROUGH 03Z.

ANY PARTIAL CLEARING HAS COME TO A HALT AS THERE WERE PLENTY OF HIGH
AND MID LEVEL CLOUDS.

LOW STRATUS HAS ALREADY TAKEN PLACE AT KGFL AT KPSF WILL LIKELY FORM
AT THE OTHER TAF SITES IN THE NEXT COUPLE OF HOURS. RIGHT NOW WE
STILL FEEL THE BEST FOR IFR WILL BE KGFL (ALREADY HAPPENING) AND
KPSF...WITH LOW MVFR AT KPOU AND HIGH END MVFR AT KALB.

HOWEVER...THIS IS A MODERATE CONFIDENCE FORECAST SO PLEASE CHECK
BACK IF YOU PLAN TO FLY TOWARD DAYBREAK!

IT WILL PROBABLY TAKE UNTIL AROUND 14Z TO LOOSE THE STRATUS AND FOG.
AFTER THAT...WE EXPECT VFR CONDITIONS TO PREVAIL. WE DID PLACE IN A
VCSH AS WE EXPECT SCATTERED CONVECTION TO DEVELOP IN THE
AFTERNOON...BUT IT DOES NOT LOOK TO BE AS NUMEROUS AS TODAY/S.

AS A POTENT UPPER LEVEL DISTURBANCE APPROACHES SUNDAY...CONVECTION
LOOKS TO RAMP UP.

THE VERY LIGHT SURFACE WIND WILL BECOME SOUTHERLY 5-10KTS ON
SUNDAY.


OUTLOOK...
SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
LABOR DAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
THURSDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE EXPECTED IN THE HUMID AIR MASS WITH
SEVERAL CHANCES OF RAINFALL.

THE BEST CHANCES FOR WIDESPREAD RAINFALL ARE SATURDAY AFTERNOON
AND EVENING AND AGAIN ON LABOR DAY. A WEAK SURFACE FRONT WILL
CROSS THE AREA THIS AFTERNOON AND EVENING WITH NUMEROUS SHOWERS
AND STORMS. SOME CLEARING BEHIND THE FRONT WILL LEAD TO FOG AND
CLOUDS SUNDAY MORNING. PARTIAL CLEARING IS EXPECTED SUNDAY
AFTERNOON WITH ISOLATED POP UP SHOWERS AND THUNDERSTORMS EXPECTED
IN THE STEAMY AIRMASS. A STRONGER LOW PRESSURE SYSTEM WILL BRING
ANOTHER CHANCE FOR WIDESPREAD SHOWERS AND STORMS SUNDAY NIGHT AND
MONDAY.

THE RH VALUES RECOVER TO CLOSE TO 100 PERCENT SUNDAY MORNING.
HIGH RH VALUES OF 60 TO 75 PERCENT WILL OCCUR SUNDAY AFTERNOON. RH
VALUES NEAR 100 PERCENT ARE FORECAST AGAIN MONDAY MORNING.

THE WINDS WILL BE FROM THE SOUTH TO SOUTHWEST AT AROUND 5 MPH
TONIGHT. TOMORROW...EXPECT WINDS FROM THE SOUTHEAST AT 10 TO 20
MPH. SOUTHEAST WINDS OF 5 TO 10 MPH ARE FORECAST FOR SUNDAY NIGHT.

&&

.HYDROLOGY...
NO WIDESPREAD HYDRO PROBLEMS ARE ANTICIPATED THE NEXT 5 DAYS ON
THE MAIN STEM RIVERS. HEAVY RAINFALL WITH LOCALIZED IMPACTS WILL BE
POSSIBLE TODAY THROUGH LABOR DAY FROM SHOWERS AND THUNDERSTORMS WITH
LOCALIZED FLASH FLOODING POSSIBLE. THE BEST CHANCE FOR WIDESPREAD
RAINFALL WILL BE TODAY AND ON LABOR DAY.

HUMID CONDITIONS WILL PERSIST...SO LOCALIZED DOWNPOURS CAN BE
EXPECTED WITH THUNDERSTORMS. ISOLATED URBAN...SMALL STREAM...AND
POOR DRAINAGE FLOODING WILL BE POSSIBLE THIS WEEKEND. SOME
MODERATE WITHIN BANK RISES ARE POSSIBLE ON LARGER STREAMS WHERE
SHOWERS AND STORMS OCCUR. ZONAL FFG VALUES REMAIN HIGH DURING THIS
TIME FRAME. HOWEVER...A QUICK INCH OR TWO OF RAINFALL FROM A SLOW
MOVING THUNDERSTORM MAY PRODUCE ISOLATED FLASH FLOODING DURING THE
WEEKEND.

RAINFALL AMOUNTS WILL BE QUITE VARIABLE DUE TO THE SHOWERY NATURE
OF THE RAIN.

FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.

&&

$$

SYNOPSIS...SND/WASULA
NEAR TERM...WASULA
SHORT TERM...SND
LONG TERM...SND
AVIATION...HWJIV
FIRE WEATHER...SND
HYDROLOGY...SND/WASULA








AREA FORECAST DISCUSSION

NWS JACKSONVILLE FL

 207 PM EDT SUN SEP 1 2013

.SHORT TERM...
ISOLATED SHOWERS ARE DEVELOPING ACROSS NE FL AND BECOMING MORE
SCATTERED NEAR THE I-75 CORRIDOR IN THE MOIST SWLY FLOW OFF THE
GULF OF MEXICO. AS TEMPS CLIMB TO NEAR 90...STORMS ARE BEGINNING
TO PRODUCE LIGHTNING. THE ACTIVITY WILL PUSH TOWARD THE EAST COAST
AND COLLIDE WITH THE SEA BREEZE THAT IS CURRENTLY PINNED TO THE
COAST. HI-RES MODELS INDICATE AN INCREASE IN COVERAGE AFTER 3 PM
THEN FADE AFTER SUNSET. THESE MODELS AND HRRR INDICATE STORMS WILL
DRIFT BACK INLAND BETWEEN I-95 AND HWY 301 INTO THE EVENING HOURS.
SHOWERS WILL DEVELOP OVER THE OUTER WATERS AFTER MIDNIGHT AND A
FEW MAY MOVE ONSHORE FROM THE GULF IN THE PRE-DAWN HOURS. FAIR
SKIES WITH LOW TEMPS IN THE 70-75 RANGE INLAND AND UPPER 70S COAST
ARE EXPECTED.

.MONDAY THROUGH WEDNESDAY...EASTERN U.S. UPPER TROUGHING WILL
AMPLIFY AGAIN AND BRING A COLD FRONT INTO SE GA BY WEDNESDAY
BEFORE WASHING OUT. SCATTERED AFTERNOON/EVENING THUNDERSTORMS
AND HOT HUMID CONDITIONS WILL CONTINUE. CONVECTION WILL INCREASE
AND REACH THE EAST COAST LATE IN THE DAY DUE TO W TO SW STEERING
FLOW.

.LONG TERM...THURSDAY THROUGH SUNDAY...FAIRLY WEAK FLOW AND MOIST
UNSTABLE AIRMASS WILL RESULT IN DIURNAL SEABREEZE THUNDERSTORMS
EACH DAY. TEMPERATURES WILL REMAIN A FEW DEGREES ABOVE AVERAGE
WITH NEAR CLIMO POPS.

.AVIATION...
PREVAILING VFR IS EXPECTED. HAVE VCSH OR VCTS FOR REMAINDER OF
AFTN. MVFR CONDITIONS ARE EXPECTED BETWEEN 08Z AND 14Z AT GNV AND
VQQ.

&&

.MARINE...
SOUTHWEST FLOW TO CONTINUE THE NEXT FEW DAYS. NOCTURNAL WIND
SURGE OFFSHORE MAY APPROACH SCEC CONDITIONS. SEAS WILL REMAIN 2
TO 3 FEET. OFFSHORE STEERING FLOW WILL PUSH STORMS INTO THE
COASTAL WATERS DURING THE LATE AFTERNOON AND EARLY EVENING.

RIP CURRENTS: LOW RISK THROUGH MONDAY DUE TO OFFSHORE WINDS.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  72  94  72  94 /  20  40  40  40
SSI  76  92  75  92 /  20  50  50  30
JAX  72  94  72  94 /  30  40  40  40
SGJ  74  91  73  92 /  30  30  30  30
GNV  71  93  71  93 /  20  40  20  30
OCF  71  93  71  94 /  20  30  10  30

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&

$$

TRABERT/ZIBURA/MCALLISTER





AREA FORECAST DISCUSSION

NWS TALLAHASSEE FL

 1108 AM EDT Sun Sep 1 2013


.NEAR TERM [Through Today]...
Despite most of the Global Models indicating that today would be a
Type 4 Sea Breeze Day (Light to Moderate SW winds (5 to 10 kts)
between 1000 and 700 mb, this morning`s TAE sounding is more
indicative of a Type 5. (same direction as a 4 but with stronger
winds (10 to 15 kts). In fact, this is showing up quite well in
this morning`s Radar imagery, as the sea breeze circulation has
become convectively active and penetrated inland much earlier than
at this time on Saturday. Therefore, raised the 12 UTC to 18 UTC
PoPs across N FL into the 30-40 percent range, and for this
afternoon, raised them to about 50 percent across the board except
along the immediate coast and the SE Big Bend. This is also shown
quite well in the Hi-Res HRRR model, which has been performing
exceptionally well this morning.

&&

.SHORT TERM [Tonight Through Tuesday]...
Tonight, the large scale longwave pattern commences rather amplified
highlighted by ridge over Wrn half of Conus, digging trough over Ern
states and high in Atlc off Cntrl FL with ridge Wwd into Cntrl Gulf
of Mex. This keeps local area in relative weakness between these
systems. At surface, high well east of N FL with axis WSW across
Cntrl FL. A cold front was noted from low Srn Ontario SSW thru OH
Valley, Missouri the Nwwd thru KS. Throughout the short term period
NAM and ECMWF slower bringing cold front into our area than GFS
hence keeping more of our area in warm sector and with noticeably
higher POPs and will lean in that direction. Will go 20-30% S-N
mainly eve rain. Lows from around 70 SE counties to low 70s
elsewhere.

On Mon, the upper level trough will continue to dig down the ERN
third of the CONUS reaching N FL with increasing storm motion from
the WSW. By evening, trough also begin to shift Ewd. This will allow
cold front to push into TN by 12z Mon then into N GA during the day
and combined with position of Nrn gulf ridge yields light onshore
flow over local area. These features combined with daytime heating
and the Gulf sea breeze will help to generate SCT convection. Type 6
(SW near 10 mph) sea breeze favors FL but will be disturbed somewhat
by approaching cold front which favor Nrn counties. GFS model PWATS
increase at TLH from 1.8 inches at 12z Mon to 2inches at 00z Tues.
Dothan increases from 1.7 to 1.9 inches same time. Will go 30-50%
S-N POPs. Aftn CAPE impressive but shear negligible. Generally light
steering flow so any cell mergers could yield locally heavy rain,
gusty winds and frequent lightning. Inland highs in low 90s.

By Tues, a series of shortwaves move thru trough further deepening
and shifting it further Ewd with axis along Ern seaboard by sundown
and into Wrn Atlc at night. By sundown, surface low ejects Newd to
Canadian Maritimes with trailing front SSW down Wrn Atlc and across
local region. Some model disagreement with ECMWF bringing front to
Srn most GA/AL while GFS pushes it into N FL with more dry air
filtering in behind over GA/AL. At 18Z Tues GFS PWATS remain around
2 inches along and south of front, but reflect modestly drier air
building in behind front. For example Dothan PWATS drop to 1.78 at
18z Tues. Conversely, ECMWF PWATS remain around 2 inches at Dothan.
Believe GFS too fast with front so will go 30-50% S-N POPS with POPs
highest where NAM/ECMWF place front. Drier air seen between H8 and
H4 may favor downdrafts and gusty winds altho with shear remaining
weak, severe wx not expected. Inland highs 90 to 92 degrees.

&&

.LONG TERM [Tuesday Night through Saturday]...
The upper level ridge centered well to our west may briefly build
into our region by mid week. Otherwise, upper level troughing will
remain the dominate weather feature through the period. A cold front
is expected to push into our CWA Wednesday and possibly stall on
Thursday. Some drier air may filter into the northern zones by
Thursday and Friday. Expect to see typical summertime diurnal
convection largely driven by the sea breeze. Temperatures will stay
near or just above seasonal normals.

&&

.AVIATION...[Through 12z Monday].
While VFR conditions prevail at the 06z TAF issuance, this is
anticipated to be short-lived. Expect LIFR conditions to develop by
sunrise at DHN/ABY with the potential for at least MVFR conditions
elsewhere. One complicating factor to this is remaining mid level
cloudiness across North Florida and offshore convection. TLH/ECP
does have a shot at some early morning storms, though confidence is
too low to include in TAFs at this time. VSBY/CIG restrictions
should end by 14z. Afternoon/evening convection is expected to be
more scattered with VCTS groups indicated at all sites. Storm
development would be later at ABY/DHN.

&&

.MARINE...
Outside of any thunderstorms, and with a weak pressure gradient in
place, very light winds and minimal seas are expected over the
coastal waters through most of the upcoming week.

&&

.FIRE WEATHER...
No concerns.

&&

.HYDROLOGY...
The Middle Suwannee River points from Ellaville through Luraville
will crest over the next 24 hours below action stage as the
Withlacoochee has already crested through the confluence with the
Suwannee. The Alapaha has crested at Jennings and will soon be
cresting near its confluence with the Suwannee near Nobles Ferry.

Modest rises from Branford on through the lower portion of the
Suwannee will continue throughout the weekend and through the latter
part of this coming week from Wilcox on down to the Gulf of Mexico
Entrance. These rises will bring the river points from Wilcox
through Fowler`s Bluff to at least action stage this week. Wilcox at
US19 has the best chance of reaching flood stage late in the week
with a lesser chance further downriver at Fowler`s Bluff.

Outside of the Suwannee River Basin, all remaining rivers in the
forecast area remain in recession. The Aucilla River will continue
to fall slowly and likely be below flood stage by mid week. Releases
from Woodruff will continue to lead to a fall in river levels at
Blountstown with the Apalachicola likely below action stage by the
weekend if the current release schedule holds.

For more information, check out the rivers and lakes tab on our
homepage.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   92  73  92  72  91 / 50  20  40  30  40
Panama City   89  75  86  75  87 / 40  20  30  20  30
Dothan        92  73  91  72  91 / 50  20  50  30  50
Albany        93  73  91  73  91 / 50  30  50  40  50
Valdosta      95  71  92  73  92 / 50  20  40  30  50
Cross City    90  72  90  72  90 / 40  20  30  20  30
Apalachicola  88  75  87  76  87 / 40  20  30  20  30

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.

&&

$$

NEAR TERM...Gould
SHORT TERM...Block
LONG TERM...Barry
AVIATION...Barry/Gould
MARINE...Block/Gould
FIRE WEATHER...Godsey
HYDROLOGY...Godsey







AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

 950 AM EDT SUN SEP 1 2013

.UPDATE...
NO CHANGES TO THE ONGOING FORECAST THIS MORNING. MORE UNIFORM
SOUTHWEST FLOW IS IN PLACE AS SEEN IN AREA SOUNDINGS. SHOWER AND
THUNDERSTORM COVERAGE IS LESS THAN THIS TIME YESTERDAY
MORNING...BUT STILL SEEING SOME ACTIVITY NEAR BEACHES IN SARASOTA
AND MANATEE COUNTIES. OUR LOCAL WRF DOES NOT SHOW MUCH ACTIVITY
THIS AFTERNOON AND THE HRRR SHOWS SLIGHTLY MORE WITH THE BEST
CHANCES INLAND DUE TO THE SOUTHWEST FLOW. SCATTERED POPS SEEM FINE
AT THIS POINT SO WILL LEAVE THE FORECAST AS IS. STRONG WIND GUSTS
WILL BE A POSSIBILITY WITH SOME OF THE THUNDERSTORMS
TODAY...ESPECIALLY WITH A MID-LEVEL DRY LAYER IN PLACE AS SEEN VIA
THE MORNING SOUNDING.

&&

.AVIATION...
MAINLY VFR CONDITIONS WITH ISOLD-SCT SHRA/TSRA EXPECTED
TO CONTINUE AND DEV ON SEA BREEZE BOUNDARIES WITH BRIEF MVFR
CIGS/VSBY AND GUSTY WINDS POSSIBLE NR TAF SITES UNTIL AROUND 00Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  90  76  90  77 /  30  20  30  20
FMY  91  76  91  76 /  30  20  30  20
GIF  92  75  93  76 /  40  20  40  20
SRQ  89  76  89  75 /  30  20  30  20
BKV  92  69  92  70 /  30  20  30  20
SPG  90  79  90  78 /  30  20  30  20

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&

$$

UPDATE...05/CARLISLE
AVIATION...25/DAVIS






AREA FORECAST DISCUSSION

NWS MIAMI FL

 905 AM EDT SUN SEP 1 2013

...FEW STRONG TSTORMS POSSIBLE THIS AFTERNOON WITH FREQUENT
LIGHTNING AND STRONG WIND GUSTS THE MAIN THREATS...

.UPDATE...THE MIAMI SOUNDING THIS MORNING SHOWS SLIGHT DRYING IN
THE LOWER LEVELS BUT STILL SUFFICIENTLY MOIST FOR CONVECTION. GPS
MET PWAT DATA SHOWS HIGHER PWATS OF 1.8 TO 2.0 INCHES FROM NAPLES
TO THE LAKE OKEECHOBEE REGION. SW LOW LEVEL FLOW CONTINUES. HRRR
SHOWS INITIAL CONVECTIVE DEVELOPMENT ACROSS THE EAST COAST METRO
AREAS JUST INLAND FROM THE COAST, THEN BECOMING CONCENTRATED OVER
THE EVERGLADES WHICH SEEMS REASONABLE GIVEN THE FLOW SET UP TODAY.
THEREFORE, HAVE SIDED WITH THIS OUTPUT. INCREASED POPS TO LIKELY
TO INCLUDE ALL OF THE INTERIOR, EVEN THOUGH HRRR ISN`T AS BULLISH
ACROSS THE LAKE REGION. HOWEVER, DID NOT SEE A REASON TO GO LOWER
POPS THERE. EXPANDED CHANCE POPS TO THE GULF COAST AND INTO THE
EAST COAST METRO AREAS WITH SLIGHT CHANCE ONLY ALONG THE IMMEDIATE
ATLANTIC COAST.

A FEW STRONG STORMS ARE POSSIBLE AGAIN THIS AFTERNOON. LAPSE RATES
ARE STEEPER THAN YESTERDAY AND THERE IS SOME DRY AIR ALOFT, SO
THE WIND GUST POTENTIAL IS THERE. WE HAD A FEW CELLS YESTERDAY
PRODUCING DOWNBURST WINDS ESTIMATED AT 50 MPH. THIS AFTERNOON WE
COULD HAVE A FEW CELLS APPROACHING SEVERE LIMITS AND WILL
HIGHLIGHT STRONG GUSTS TO 55 MPH POSSIBLE. ISOLATED STREET
FLOODING IS POSSIBLE AS WELL WHERE STORMS TRAIN. /GREGORIA

&&

.PREV DISCUSSION... /ISSUED 647 AM EDT SUN SEP 1 2013/

AVIATION...
HIGH PRESSURE IS BEGINNING TO BUILD IN FROM THE EAST. THIS HAS
CAUSED THE UPPER LEVEL LOW THAT HAS BEEN OVER SOUTH FLORIDA TO
DISSIPATE. THERE ARE SOME ISOLATED SHOWERS AND THUNDERSTORMS
MOVING NORTHWARD, ACROSS CENTRAL FLORIDA. THIS IS LIKELY FROM
OUTFLOW BOUNDARIES ASSOCIATED WITH YESTERDAYS CONVECTION OVER
CUBA. THIS IS EXPECTED TO DIMINISH BY MID MORNING.

FOR THE REST OF THE DAY, THERE IS STILL A SOUTHERLY FLOW OVER THE
AREA. THIS WILL BE INFLUENCED BY THE SEA AND GULF BREEZES EARLY
THIS AFTERNOON. WHEN THE BREEZES DO INITIATE, THEY WILL CAUSE
CONVECTIVE SHOWERS AND SOME THUNDERSTORMS TO DEVELOP AND MOVE BOTH
INLAND AND NORTH. THE FOCUS FOR DEVELOPMENT IS EXPECTED TO SHIFT
TO THE LAKE OKEECHOBEE REGION LATER THIS AFTERNOON. IN THE
MEANTIME, THERE IS UNCERTAINTY AS TO WHERE AND WHEN SHOWERS WILL
CONVERT TO THUNDERSTORMS, SO ONLY VCSH IN THE TAFS AT THIS TIME.
AS MODELS AND OBSERVATIONS MAKE THE PICTURE MORE CLEAR, VCTS MAY
NEED TO BE ADDED TO ANY OR EVEN ALL THE TAF SITES LATER THIS
MORNING.

PREV DISCUSSION... /ISSUED 304 AM EDT SUN SEP 1 2013/

SHORT TERM...
THE OUTFLOW BOUNDARY FROM YESTERDAYS AFTERNOON CONVECTION OVER
CUBA HAS WORKED INTO FLORIDA BAY AND GULF WATERS OF SOUTH FLORIDA
EARLY THIS MORNING. THIS OUTFLOW HAS ALLOWED FOR SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS TO DEVELOP OVER THE GULF WATERS OF
SOUTH FLORIDA EXTENDING EAST INTO THE FLORIDA BAY AND NORTHERN
FLORIDA KEYS. THE SHOWERS AND THUNDERSTORMS WILL DISSIPATE TOWARDS
SUNRISE AS THE OUTFLOW BOUNDARY DISSIPATES...BUT COULD WORK INTO
THE WESTERN AND SOUTHERN COASTAL AREAS OF SOUTH FLORIDA. SO HAVE
PUT IN A 20 PERCENT POPS FOR THESE AREAS THROUGH THE EARLY MORNING
HOURS.

THE UPPER LEVEL LOW THAT HAS BEEN HANGING AROUND SOUTH FLORIDA FOR
THE LAST SEVERAL DAYS WILL SLOWLY MOVE WEST INTO THE GULF WATERS
OF MEXICO TODAY. THIS WILL ALLOW FOR THE WESTERN ATLANTIC RIDGE
TO BUILD INTO SOUTH FLORIDA...AND ALLOW FOR BOTH THE EAST AND WEST
COAST SEA BREEZES TO DEVELOP AND PUSH INLAND ACROSS THE AREA. THE
STEERING FLOW WILL ALSO BE LIGHT FROM THE SOUTH OVER SOUTH FLORIDA
TODAY. SO ISOLATED TO SCATTERED POPS WILL ONCE AGAIN COVER SOUTH
FLORIDA TODAY WITH THE HIGHEST POPS AROUND LAKE OKEECHOBEE.

THE HIGH WILL REMAIN IN PLACE OVER SOUTH FLORIDA ON LABOR DAY
WHICH WILL KEEP A LIGHT SOUTHERLY WIND FLOW OVER SOUTH
FLORIDA...AND ALLOW FOR BOTH THE EAST AND WEST COAST SEA BREEZES
TO DEVELOP AND PUSH INLAND. SO THE POPS FOR LABOR DAY WILL ONCE
AGAIN BE IN THE ISOLATED TO SCATTERED RANGE WITH THE HIGHEST POPS
OVER THE LAKE OKEECHOBEE REGION.

THE HIGH WILL THEN MOVE NORTH INTO CENTRAL FLORIDA FOR THE MIDDLE
OF THIS WEEK. THIS WILL ALLOW FOR THE STEERING FLOW TO BECOME MORE
EASTERLY OVER SOUTH FLORIDA...AND FOCUS THE HIGHEST SCATTERED POPS
OVER THE INTERIOR AND WEST COAST METRO AREAS. THE EAST COAST METRO
AREAS WILL SEE ISOLATED TO LOW END SCATTERED POPS FOR THE MIDDLE
OF THIS WEEK.

THE HIGHS FOR LABOR DAY INTO MIDDLE OF THIS WEEK WILL BE IN THE
LOWER TO MID 90S...EXCEPT AROUND 90 FOR THE EAST COAST METRO
AREAS. THIS WILL ALLOW FOR THE HEAT INDEX READINGS TO BE IN THE
100 TO 105 RANGE OVER MOST OF SOUTH FLORIDA...EXCEPT FOR THE EAST
COAST METRO AREAS WHERE THEY WILL BE AROUND 100.

LONG TERM...
THE HIGH WILL REMAIN OVER CENTRAL FLORIDA FOR END OF THIS WEEK
INTO NEXT WEEKEND. THIS WILL KEEP A EASTERLY WIND FLOW OVER SOUTH
FLORIDA WHICH IN TURN WILL KEEP THE HIGHEST SCATTERED POPS OVER
THE INTERIOR AND WEST COAST METRO AREAS.

THERE IS A TROPICAL WAVE LOCATED JUST EAST OF THE LESSER ANTILLES
THAT WILL MOVE WEST NORTHWEST THROUGH THE WEEK...AND PASS SOUTH OF
THE AREA BY LATE THIS WEEK INTO EARLY NEXT WEEKEND. THIS WAVE
COULD BRING IN SOME DEEPER TROPICAL MOISTURE TO THE AREA DURING
THIS TIME FRAME. SO WILL CONTINUE TO MONITOR THE LATEST MODEL RUNS
ON HOW MUCH MOISTURE WORKS INTO THE AREA WITH THE PASSAGE OF THE
TROPICAL WAVE TO THE SOUTH...AND TO SEE IF THE POPS NEED TO BE
RAISED OVER SOUTH FLORIDA FOR LATE THIS WEEK INTO EARLY NEXT WEEK
IN LATER FORECAST.

MARINE...
THE WINDS WILL BE AROUND 5 KNOTS TODAY INTO LABOR DAY FROM THE SOUTH
TO SOUTHEAST DIRECTION. THE WINDS WILL THEN BECOME MORE EASTERLY
AND SLOWLY INCREASE TO 10 TO 15 KNOTS BY END OF NEXT WEEK. THIS WILL
KEEP THE SEAS AT 2 FEET OR LESS IN BOTH THE ATLANTIC AND GULF
WATERS OF SOUTH FLORIDA THROUGH THE WEEK. SO BOATING CONDITIONS
WILL REMAIN GOOD OVER ALL OF SOUTH FLORIDA WATERS THROUGH THE WEEK
OUTSIDE OF ANY SHOWERS AND THUNDERSTORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  90  76  90  77 / 30 20 30 20
FORT LAUDERDALE  89  78  90  79 / 20 20 20 20
MIAMI            90  77  91  79 / 40 20 30 20
NAPLES           89  75  90  76 / 50 20 30 20

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

$$





AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 941 PM EDT MON SEP 2 2013

.SYNOPSIS...
A SURFACE LOW PRESSURE TROUGH WILL PERSIST INLAND THROUGH TONIGHT.
A WEAK COLD FRONT WILL PUSH INTO THE AREA TUESDAY NIGHT AND
WEDNESDAY...LINGERING NEARBY THURSDAY...BEFORE DISSIPATING BY
FRIDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FROM THE NORTH
FOR LATE WEEK INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
IT TURNED OUT TO BE A BUSY EVENING AFTER ALL. STRONG TO SEVERE
TSTMS WITH AN INCREDIBLE AMOUNT OF CLOUD TO GROUND LIGHTNING
DEVELOPED EAST OF I-95 THIS EVENING AS THE SEA BREEZE CIRCULATION
MET UP WITH A LARGE OUTFLOW BOUNDARY THAT WAS GENERATED BY EARLIER
INLAND TSTM ACTIVITY. AT 03/0130Z...RADAR SHOWED TSTMS EXITING OFF
WILD DUNES AND FOLLY BEACH...WHILE A SECOND AREA OF TSTMS WAS
MOVING ACROSS PARTS OF LIBERTY...MCINTOSH AND LONG COUNTIES. ONCE
THIS ACTIVITY PUSHES OFFSHORE...EXPECT A MUCH QUIETER OVERNIGHT
PERIOD. SATELLITE AND RAP VORTICITY PLOTS SHOW A SHORTWAVE IS
MOVING ACROSS THE UPSTATE AND IS PROGGED TO BRUSH THE AREA
OVERNIGHT. THERE MAY BE JUST ENOUGH LIFT AND RESIDUAL INSTABILITY
TO EEK OUT A FEW SHOWERS OR EVEN A TSTM...BUT THE ATMOSPHERE HAS
LIKELY BEEN SUFFICIENTLY OVERTURNED SUCH THAT ANY ACTIVITY WOULD
BE ISOLATED IN NATURE. WILL HOLD ONTO CATEGORICAL POPS ACROSS THE
FAR SOUTH THROUGH ABOUT MIDNIGHT...DIMINISHING TO 20-30 PERCENT
ELSEWHERE. SLIGHT CHANCE POPS WILL BE MAINTAINED OVERNIGHT.

MANY AREAS HAVE ALREADY REACHED THEIR PREVIOUSLY FORECASTED
OVERNIGHT LOWS. SUSPECT TEMPERATURES WILL CHANGE LITTLE FOR THE
REMAINDER OF THE NIGHT. TRIED TO CAPTURE THESE TRENDS IN THE HOURLY
TEMPERATURE FORECASTS.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...THE AXIS OF THE UPPER TROUGH WILL CROSS THE EAST COAST
MID DAY...ALLOWING A COLD FRONT TO STEADILY SLIP SOUTHEAST TOWARD
THE FORECAST AREA. TWO DISTINCT BANDS OF VORTICITY ENERGY WILL BE
ROUNDING THE BASE OF THE UPPER TROUGH AS THE DAY PROGRESSES...WITH
THE LATTER SHORTWAVE PULLING THE FRONT TOWARD THE COASTLINE AFTER
MIDNIGHT EARLY WEDNESDAY MORNING. CONSIDERING ENHANCED CONVERGENCE
ALONG AND AHEAD OF THE FRONT...COMBINED WITH DECENT SYNOPTIC LEVEL
SUPPORT FROM THE SHORTWAVE ENERGY...EXPECT A 30 TO 40 PERCENT
CHANCE FOR SHOWERS/THUNDERSTORMS BY THE AFTERNOON. BEST COVERAGE
IS EXPECTED ACROSS THE NORTHERN HALF OF THE FORECAST
AREA...CLOSEST TO THE DESCENDING FRONT...HOWEVER SCATTERED
CONVECTION COULD DEVELOP JUST ABOUT ANYWHERE ACROSS THE REGION.
HAVE MAINTAINED MENTION OF ISOLATED TO SCATTERED THUNDERSTORMS
INTO THE NIGHTTIME HOURS DUE TO CONTINUED SUPPORT FROM THE
APPROACHING FRONT AND UPPER LEVEL ENERGY...BEFORE COVERAGE
DECREASES FROM WEST TO EAST BEHIND THE DEPARTING SHORTWAVE PRIOR
TO SUNRISE WEDNESDAY. WARM WEST FLOW IN THE LOW LEVELS AND PRE-
FRONTAL COMPRESSION WILL ALLOW TEMPERATURES TO INCREASE WELL ABOVE
SEASONAL NORMALS...PEAKING IN THE LOWER 90S INLAND. HIGH DEWPOINTS
WILL ALSO SUPPORT HEAT INDICES IN THE 100 TO 102 DEGREE RANGE
DURING THE MID TO LATE AFTERNOON PERIOD.

WEDNESDAY AND THURSDAY...AS THE UPPER LEVEL PATTERN BECOMES WEAKER
MID TO LATE WEEK...THE COLD FRONT AND ASSOCIATED SURFACE TROUGH
WILL STALL AND DISSIPATE ALONG THE SOUTHERN BORDER OF THE FORECAST
AREA. THE SURFACE PATTERN WILL ALSO BECOME SOMEWHAT ILL-DEFINED AS
HIGH PRESSURE IS SLOW TO BUILD INTO THE REGION NORTH OF THE
MEANDERING FRONT. NUMERICAL MODEL SOLUTIONS SHOW VARYING DEGREES
OF MAINLY DIURNAL CONVECTION WEDNESDAY AND THURSDAY...WITH
CONSENSUS SUGGESTING THAT AT LEAST ISOLATED TO SCATTERED
SHOWERS/THUNDERSTORMS WILL DEVELOP ALONG AND INLAND OF THE
SEABREEZE DURING THE FAVORED AFTERNOON/EARLY EVENING HOURS EACH
DAY. HAVE THUS ADVERTISED A RATHER TYPICAL SUMMERTIME CONVECTIVE
PATTERN INTO LATE WEEK...INDICATING POPS IN THE 20 TO 30 PERCENT
RANGE AND TEMPERATURES PEAKING AROUND 90 DEGREES AWAY FROM THE
LOCALLY COOLER COASTLINE...STILL A DEGREE OR TWO WARMER THAN
NORMAL FOR EARLY SEPTEMBER.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A VERY WEAK...BROAD UPPER LEVEL TROUGH WILL SETUP ACROSS THE
SOUTHEAST UNITED STATES DURING THE EXTENDED PERIOD. AT THE SURFACE
WEAK HIGH PRESSURE TO THE NORTH WILL GRADUALLY SHIFT INTO THE
WESTERN ATLANTIC...WITH A MOIST RETURN FLOW DEVELOPING. THERE ARE
FEW DISCERNIBLE FEATURES TO HANG OUR HATS ON THOUGH THERE LOOKS TO
BE A SHORTWAVE THAT MOVES THROUGH ON SATURDAY...POTENTIALLY LEADING
TO BETTER CONVECTIVE COVERAGE. OTHERWISE WE EXPECT MAINLY DIURNAL
CONVECTION WITH TEMPS NEAR NORMAL.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
RISK FOR TSTM IMPACTS WILL BE GREATEST AT KCHS THROUGH ABOUT 02Z.
TSTMS HAVE MOVED THROUGH KSAV BUT WILL LINGER CLOSE TO THAT
TERMINAL FOR ANOTHER 1-2 HOURS. ONCE THIS ACTIVITY CLEARS THE
TERMINALS...EXPECT VFR CONDITIONS TO PREVAIL FOR THE REMAINDER OF
THE PERIOD.

EXTENDED AVIATION OUTLOOK...SCATTERED CONVECTION IS EXPECTED TUESDAY
WITH A FRONTAL PASSAGE...THEN SHOWER/THUNDERSTORM POTENTIAL WILL
OCCUR MAINLY DURING THE AFTERNOON/EVENING PERIODS WEDNESDAY AND
THURSDAY. THERE COULD BE SOME FOG AND LOW CEILING ISSUES TUESDAY
NIGHT AND WEDNESDAY...AS THE FRONT LINGERS OVER THE AREA.

&&

.MARINE...
TONIGHT...THE SYNOPTIC SETUP WILL BE QUITE SIMILAR TO LAST NIGHT. SW
LOW LEVEL FLOW WILL PERSIST THANKS TO THE INLAND TROUGH OF LOW
PRESSURE. THE PRESSURE GRADIENT WILL TIGHTEN A BIT AND RESULT IN
ANOTHER MODEST SURGE OVER THE WATERS THROUGH THE OVERNIGHT. WIND
SPEEDS WILL BE IN THE 15-20 KT RANGE FOR SEVERAL HOURS. SEAS WILL
GENERALLY BE 2-3 FT WITHIN 20 NM...EXCEPT UP TO 4 FT FOR THE
CHARLESTON COUNTY WATERS...AND 3-4 BEYOND.

TUESDAY THROUGH SATURDAY...MODERATE SOUTHWEST FLOW AHEAD OF AN
APPROACHING COLD FRONT ON TUESDAY WILL BECOME LIGHT SOUTHERLY BY
WEDNESDAY...AS THE FRONT STALLS OVER THE AREA. A WEAK PRESSURE
PATTERN INTO THE WEEKEND WILL YIELD MINIMAL WINDS/SEAS THROUGH
THE REMAINDER OF THE PERIOD. CONDITIONS ARE EXPECTED TO BE BELOW
SMALL CRAFT ADVISORY CONDITIONS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

ST





AREA FORECAST DISCUSSION

NWS PEACHTREE CITY GA

 203 PM EDT SUN SEP 1 2013

.PREV DISCUSSION... /ISSUED 1221 PM EDT SUN SEP 1 2013/

UPDATE...
HRRR HAS THE BEST HANDLE ON THE ONGOING CONVECTION OVER NORTH GA.
WHILE IT IS SHOWING A LULL AS THE OUTFLOW FROM MCS INTERACTS WITH
INSTABILITY...CAPES 1500-2000 ACROSS PORTIONS OF WEST AND CENTRAL
GA. CURRENT THINKING AS AREA OVER NORTH GA WILL TRANSITION
SOUTHWARD WITHOUT THE LULL AND HAVE ADJUSTED POP/WEATHER TRENDS
ACCORDINGLY. OTHERWISE CURRENT FORECAST TRENDS PRETTY MUCH ON
TRACK EXCEPT FOR MAX TEMPERATURES IN PORTIONS OF NORTH GA WHICH
WERE ALSO TWEAKED. UPDATED FORECAST PRODUCTS WILL BE ISSUED
SHORTLY.

PREV DISCUSSION... /ISSUED 746 AM EDT SUN SEP 1 2013/

UPDATE...
HAVE UPPED THE POPS ACROSS NORTHERN GA THIS MORNING. HAVE SEEN A
STEADY INCREASE IN COVERAGE AHEAD OF WEAKENING MCS.

PREV DISCUSSION... /ISSUED 324 AM EDT SUN SEP 1 2013/

SHORT TERM /TODAY THROUGH MONDAY/...
HIGH PRESSURE HAS MOVED OFFSHORE...WHILE A STALLED BOUNDARY
REMAINS SITUATED ACROSS THE OHIO VALLEY. REGIONAL RADAR AND
SATELLITE SHOWS A WEAKENING MCS DROPPING SOUTH ACROSS SOUTHERN IN
AND W KY. ANOTHER AREA OF WEAKENING STORMS IS ACROSS THE TN/NC
BORDER. JUST A FEW CLOUDS ACROSS THE CWFA THIS MORNING...BLOW OFF
FROM THE STORMS TO THE NORTH. PATCHY FOG HAS ALSO DEVELOPED BUT
SHOULD BEGIN TO BURN OFF AFTER SUNRISE.

THE LATEST RUN OF THE HRRR BRINGS THE REMNANT SHOWERS/
THUNDERSTORMS FROM THE COMPLEXES UP NORTH ACROSS NORTHERN GA
DURING THE FIRST PART OF THE MORNING. THIS SEEMS REASONABLE...AS
THE ACTIVITY SHOULD CONTINUE TO WEAKEN AS IT APPROACHES THE
NORTHERN METRO. DO THINK THAT STORMS LATER IN THE DAY COULD FOCUS
UPON THE LEFTOVER OUTFLOW/DIFFERENTIAL HEATING BOUNDARY. HAVE
TRIED TO ORIENT POPS ACCORDING TO THE EARLY HOURS OF THE HRRR
OUTPUT.

MODELS DO HAVE A WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW ACROSS
NORTHERN GA LATER IN THE AFTERNOON. THIS FEATURE SHOULD SERVE TO
FOCUS/INITIATE SCT/NMRS STORMS INTO THE EARLY EVENING. MODELS KEEP
THE ATMOS UNSTABLE OVERNIGHT...AND WITH ABUNDANT LOW LEVEL
MOISTURE...SCT/ISO STORMS WILL BE POSSIBLE THROUGH THE OVERNIGHT
HOURS. TOWARDS 12Z MONDAY...THE GFS LOOKS AS IF IT IS TRYING TO
BRING AN MCS ACROSS NORTHERN GA. THE NAM DOESN`T REALLY HAVE THIS
FEATURE IN THE MID LEVELS OR THE 800MB - 300MB THICKNESS PATTERN.
THE GFS MAY BE SUFFERING FROM CONVECTIVE FEEDBACK...BUT WILL KEEP
SCT POPS IN ACROSS THE NORTH OVERNIGHT. IF THE COMPLEX DOES INDEED
DEVELOP...POPS MAY HAVE TO BE RAISED.

FRONT OVER THE MID ATLANTIC WILL SHIFT SOUTHWARD THROUGH MONDAY AND
CONTINUE TO APPROACH THE CWFA FROM THE NORTH. GOOD SOUTHERLY FLOW
AHEAD OF THE BOUNDARY AND INSTABILITY WILL LEAD TO ANOTHER DAY OF
SCT THUNDERSTORMS. SEVERE WEATHER IS NOT ANTICIPATED TODAY OR
MONDAY...BUT A FEW OF THE STORMS COULD BE STRONG. IN ADDITION...
LOCALLY HEAVY RAINFALL ACROSS NORTHERN GA WILL BE POSSIBLE
ESPECIALLY ON MONDAY. STORMS WILL ALSO BE CAPABLE OF PRODUCING
OCCASIONAL LIGHTNING STRIKES AND GUSTY WINDS.

NLISTEMAA

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...
18Z UPDATE...
LINE OF CONVECTION DEVELOPING OVER THE ATL TO AHN TAF SITES WILL
SLOWLY SINK TO THE SOUTH THROUGH THIS EVENING. ANTICIPATE STORMS
WILL BE SOUTH OF ATL AFTER 20Z AND IMPACT CSG/MCN 20-24Z. VFR
CONDITIONS EXPECTED OUTSIDE OF CONVECTION WITH MVFR AND WIND GUSTS
TO NEAR 30KTS EXPECTED. LOW CLOUDS WILL DEVELOP TOWARD MORNING
AIDED BY THE SATURATED GROUND WITH IFR/LOW MVFR CIGS EXPECTED AT
THIS TIME. WEST WINDS WILL PREVAIL THROUGH THE PERIOD.

//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE IN WINDS...VISIBILITY.
MEDIUM CONFIDENCE IN CIGS OVERNIGHT...CONVECTIVE TIMING.

ATWELL

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  70  90  72 /  60  40  40  30
ATLANTA         89  73  90  74 /  60  40  40  40
BLAIRSVILLE     83  66  84  68 /  60  30  60  40
CARTERSVILLE    89  71  89  71 /  60  40  40  40
COLUMBUS        92  75  93  74 /  60  50  40  30
GAINESVILLE     88  69  88  73 /  60  40  40  40
MACON           91  71  91  72 /  60  50  40  30
ROME            88  70  90  72 /  60  30  60  40
PEACHTREE CITY  90  69  90  71 /  60  40  40  30
VIDALIA         91  74  93  74 /  50  40  40  30

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...ATWELL
LONG TERM....30
AVIATION...ATWELL






AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 154 PM EDT SUN SEP 1 2013

.SYNOPSIS...
WEAK ATLANTIC HIGH PRESSURE WILL RESIDE OVER THE AREA THROUGH MONDAY.
A COLD FRONT WILL PUSH THROUGH TUESDAY NIGHT AND WEDNESDAY WITH WEAK
CANADIAN HIGH PRESSURE BUILDING IN FROM THE NORTH. THE HIGH WILL SHIFT
OFF THE COAST LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY THIS AFTERNOON...ISOLATED SHOWERS ARE STARTING TO DEVELOP
MAINLY UPSTREAM ACROSS THE MIDLANDS WITHIN THE SURFACE TROUGH. A
COUPLE OF SHOWERS HAVE ALSO STARTED TO BUBBLE OVER SOUTHEAST
GEORGIA. THERE IS NO CHANGE IN THE FORECAST THINKING FOR
CONVECTIVE ACTIVITY THIS AFTERNOON/EVENING. PREVIOUS DISCUSSION
FOLLOWS BELOW.

LATE THIS MORNING...THE LACK OF ANY FOG/STRATUS HAS RESULTED IN
CLEAR SKIES ACROSS THE FORECAST AREA. THIS IS ALLOWING TEMPS TO
WARM QUITE RAPIDLY AND SOME AREAS ALREADY IN THE MID 80S. A CU
FIELD SHOULD START DEVELOPING VERY SOON AND WILL ENCOMPASS THE
ENTIRE FORECAST AREA. THE MAIN FORECAST ISSUE FOR TODAY REVOLVES
AROUND THE COVERAGE AND INTENSITY OF DIURNAL CONVECTION. THE
MODELS ACROSS THE SPECTRUM ARE SENDING MIXED SIGNALS. SOME OF THE
HI-RES RUNS SUCH AS THE HRRR SHOW LITTLE MORE THAN ISOLATED WEAK
CONVECTION. ON THE OTHER HAND...THE 12Z NAM HAS COME IN WITH AN
UPWARD TREND IN ITS COVERAGE AND INTENSITY. CURRENTLY...THERE IS A
WELL DEFINED AREA OF NVA ALOFT NOTED ON WATER VAPOR IMAGERY IN
ADVANCE OF THE POTENT SHORTWAVE DRIVING ONGOING CONVECTION OVER
THE TENNESSEE VALLEY. THIS NVA WILL LIKELY HANG ON UNTIL LATE IN
THE AFTERNOON BEFORE THE UPSTREAM ENERGY DISRUPTS IT. ANOTHER
INTERESTING NOTE CONCERNS THE THERMODYNAMIC PARAMETERS FROM THE
MODIFIED 12Z RAOB. USING A TEMP/DP OF SOMETHING AROUND 92/73
RESULTS IN CAPE VALUES AROUND 3000 J/KG...WITH DCAPES GREATER THAN
1000 J/KG THANKS TO A GOOD DEAL OF DRY MID LEVEL AIR. THE MAIN
SOURCE OF LOW LEVEL CONVERGENCE WILL BE THE SEA BREEZE...THE BEST
CONSENSUS SEEMS TO FAVOR ISOLATED TO SCATTERED COVERAGE IN THE
MID/LATE AFTERNOON HOURS. GIVEN THE NEAR STORM ENVIRONMENT...THIS
SEEMS TO BE A DAY WITH LIMITED COVERAGE BUT THE POTENTIAL FOR A
COUPLE STRONG TO SEVERE STORMS DEPENDING ON HOW THE SEA BREEZE AND
OUTFLOW BOUNDARIES INTERACT. AS I SAID EARLIER...TEMPS ARE RISING
QUICKLY AND WITH INCREASED LOW LEVEL THICKNESSES...HIGHS WILL BE
IN THE LOW 90S. SUCH VALUES WILL RUN ABOUT 4-5 DEGREES ABOVE CLIMO
FOR EARLY SEPTEMBER.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
TONIGHT...MOST AREAS LIKELY TO SEE DRY WEATHER. THE AREA WHERE SOME
ISOLATED NOCTURNAL CONVECTION MAY CROP UP OVERNIGHT COULD BE IN
THE SAME AREAS BORDERING THE MIDLANDS AND PEE DEE WHERE A BIT MORE
MID LEVEL TROFFINESS IS NOTED. COASTAL AREAS WILL KEEP A SLIGHT SW
BREEZE GOING OVERNIGHT AS PATTERN IS FAVORABLE FOR NOCTURNAL
JETTING ALONG THE SOUTH CAROLINA COAST.

A BROAD UPPER TROUGH WILL SIT OVER THE AREA ON MONDAY WITH
SUBSTANTIAL WESTERLY FLOW IN THE LOWER LEVELS. A WELL-DEFINED LEE
TROUGH COMBINED WITH MODEST SURFACE BASED CAPE SHOULD ALLOW FOR
SCATTERED SHOWERS/TSTMS ACROSS INLAND AREAS BY EARLY AFTERNOON.
THE SEABREEZE WILL BE PINNED NEAR THE COAST MUCH OF THE DAY BUT
COULD BECOME A PLAYER LATER IN THE AFTERNOON AS IT STARTS TO NUDGE
INLAND. WESTERLY STEERING FLOW SHOULD BRING INLAND CONVECTION
TOWARD THE COAST AS THE DAY PROGRESSES. OUR BEST COVERAGE LOOKS TO
BE LATE AFTERNOON INTO THE EVENING THOUGH A FEW STORMS COULD
CONTINUE OVERNIGHT GIVEN SUCH A RICH AIRMASS IN PLACE.

THE UPPER TROUGH WILL DEEPEN OVER THE EASTERN UNITED STATES ON
TUESDAY WITH A COLD FRONT SLOWLY DROPPING SOUTHEAST TOWARD THE AREA.
DEWPOINTS RISING INTO THE MIDDLE 70S WITH TEMPS PUSHING INTO THE
LOWER 90S WILL YIELD SUBSTANTIAL SURFACE BASED CAPES RANGING FROM
2000 TO 3000 J/KG. ADDITIONALLY SHORTWAVE ENERGY WILL PUSH IN FROM
THE WEST DURING THE AFTERNOON. THUS FAIRLY GOOD COVERAGE OF SHOWERS
AND TSTMS EXPECTED DURING THE DAY TUESDAY...ESPECIALLY LATER IN THE
AFTERNOON ONCE THE CONVECTIVE BOUNDARIES BEGIN INTERACTING WITH THE
SEABREEZE.

SCATTERED CONVECTION MAY CONTINUE INTO TUESDAY NIGHT BEFORE TAPERING
OFF FROM NORTH TO SOUTH. THE FRONT SHOULD PUSH SOUTH OF THE AREA ON
WEDNESDAY WITH SLIGHTLY DRIER AND COOLER CONDITIONS IN ITS WAKE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CANADIAN HIGH PRESSURE WILL PREVAIL FOR THE BEGINNING OF THE PERIOD
BUT STEADILY SHIFT EAST WITH A RETURN FLOW SETTING UP ON THE SW
PERIPHERY. MOST AREAS WILL BE DRY WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT. DIURNAL CONVECTION RETURNS TO THE FORECAST FRIDAY THROUGH
SUNDAY AS LOW-LEVEL MOISTURE INCREASES AND ANOTHER UPPER TROUGH SETS
UP SHOP.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THE BIGGEST TAF CONCERN FOR THE UPCOMING FORECAST PERIOD IS THE
POTENTIAL FOR IMPACTS FROM SHOWERS/THUNDERSTORMS THIS AFTERNOON
AND EVENING. SO FAR...DEVELOPMENT HAS BEEN SLOW AND EVEN THE CU
FIELD HAS BEEN QUITE MUTED THANKS TO SOME SUPPRESSION ALOFT.
MODELS DO SHOW MOST OF THE DEVELOPMENT IN THE LATE AFTERNOON HOURS
AND THAT IS WHAT IS PRESENTED IN THE TAF/S. THE MODELS TEND TO
PLACE THE BEST COVERAGE CLOSEST TO KCHS SO I HAVE ADDED THE MOST
DETAIL THERE WITH PREVAILING VCTS STARTING AT 20Z AND THEN A TEMPO
FOR MVFR TSRA CONDITIONS BETWEEN 21-23Z. I HAVE LEFT KSAV WITH
JUST A VCTS FOR NOW...BUT WILL CONTINUE TO MONITOR RADAR TRENDS
FOR AMENDMENTS AT BOTH SITES. MOST OF THE COVERAGE WILL THEN DRIFT
INLAND LATE THIS EVENING AND THE FORECAST IS VFR THEREAFTER. SOME
GUIDANCE HINTS AT THE POSSIBILITY FOR MVFR CEILINGS
OVERNIGHT...BUT CHANCES ARE TOO LOW TO WARRANT A MENTION AT THIS
POINT.

EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND TSTMS MONDAY
THROUGH TUESDAY NIGHT WITH OCCASIONAL REDUCTIONS IN CEILING AND
VISIBILITY.

&&

.MARINE...
FAIRLY LIGHT WINDS AND SEAS 2 TO 3 FT EXPECTED THROUGH THE AFTERNOON
HOURS. A STRONGER NOCTURNAL SURGE IS ANTICIPATED TONIGHT AS THE
BOUNDARY LAYER PRES GRADIENT TIGHTENS. THERE MAY BE A SHORT
DURATION WHERE WINDS APPROACH SMALL CRAFT ADVISORY CONDITIONS IN
FREQUENT GUSTS OVER 20 KT BUT WE HAVE CAPPED OFFSHORE FLOW AT 15
TO 20 KT FOR NOW. SEAS WILL BUILD TO NEAR 4 FT BEYOND 20 NM
OFFSHORE.

MONDAY THROUGH FRIDAY...WEATHER CONDITIONS WILL REMAIN BELOW
ADVISORY CRITERIA. SOUTH TO SOUTHWEST WINDS WILL PERSIST UNTIL
TUESDAY AHEAD OF THE COLD FRONT. ONCE THE FRONT PUSHES INTO THE
AREA...WINDS WILL BECOME VARIABLE AND LIGHT...WITH SEAS NO HIGHER
THAN 2-3 FEET.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...BSH
MARINE...JRL





AREA FORECAST DISCUSSION

NWS PEACHTREE CITY GA

 1221 PM EDT SUN SEP 1 2013

.UPDATE...
HRRR HAS THE BEST HANDLE ON THE ONGOING CONVECTION OVER NORTH GA.
WHILE IT IS SHOWING A LULL AS THE OUTFLOW FROM MCS INTERACTS WITH
INSTABILITY...CAPES 1500-2000 ACROSS PORTIONS OF WEST AND CENTRAL
GA. CURRENT THINKING AS AREA OVER NORTH GA WILL TRANSITION
SOUTHWARD WITHOUT THE LULL AND HAVE ADJUSTED POP/WEATHER TRENDS
ACCORDINGLY. OTHERWISE CURRENT FORECAST TRENDS PRETTY MUCH ON
TRACK EXCEPT FOR MAX TEMPERATURES IN PORTIONS OF NORTH GA WHICH
WERE ALSO TWEAKED. UPDATED FORECAST PRODUCTS WILL BE ISSUED
SHORTLY.

&&

.PREV DISCUSSION... /ISSUED 746 AM EDT SUN SEP 1 2013/

UPDATE...
HAVE UPPED THE POPS ACROSS NORTHERN GA THIS MORNING. HAVE SEEN A
STEADY INCREASE IN COVERAGE AHEAD OF WEAKENING MCS.

PREV DISCUSSION... /ISSUED 324 AM EDT SUN SEP 1 2013/

SHORT TERM /TODAY THROUGH MONDAY/...
HIGH PRESSURE HAS MOVED OFFSHORE...WHILE A STALLED BOUNDARY
REMAINS SITUATED ACROSS THE OHIO VALLEY. REGIONAL RADAR AND
SATELLITE SHOWS A WEAKENING MCS DROPPING SOUTH ACROSS SOUTHERN IN
AND W KY. ANOTHER AREA OF WEAKENING STORMS IS ACROSS THE TN/NC
BORDER. JUST A FEW CLOUDS ACROSS THE CWFA THIS MORNING...BLOW OFF
FROM THE STORMS TO THE NORTH. PATCHY FOG HAS ALSO DEVELOPED BUT
SHOULD BEGIN TO BURN OFF AFTER SUNRISE.

THE LATEST RUN OF THE HRRR BRINGS THE REMNANT SHOWERS/
THUNDERSTORMS FROM THE COMPLEXES UP NORTH ACROSS NORTHERN GA
DURING THE FIRST PART OF THE MORNING. THIS SEEMS REASONABLE...AS
THE ACTIVITY SHOULD CONTINUE TO WEAKEN AS IT APPROACHES THE
NORTHERN METRO. DO THINK THAT STORMS LATER IN THE DAY COULD FOCUS
UPON THE LEFTOVER OUTFLOW/DIFFERENTIAL HEATING BOUNDARY. HAVE
TRIED TO ORIENT POPS ACCORDING TO THE EARLY HOURS OF THE HRRR
OUTPUT.

MODELS DO HAVE A WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW ACROSS
NORTHERN GA LATER IN THE AFTERNOON. THIS FEATURE SHOULD SERVE TO
FOCUS/INITIATE SCT/NMRS STORMS INTO THE EARLY EVENING. MODELS KEEP
THE ATMOS UNSTABLE OVERNIGHT...AND WITH ABUNDANT LOW LEVEL
MOISTURE...SCT/ISO STORMS WILL BE POSSIBLE THROUGH THE OVERNIGHT
HOURS. TOWARDS 12Z MONDAY...THE GFS LOOKS AS IF IT IS TRYING TO
BRING AN MCS ACROSS NORTHERN GA. THE NAM DOESN`T REALLY HAVE THIS
FEATURE IN THE MID LEVELS OR THE 800MB - 300MB THICKNESS PATTERN.
THE GFS MAY BE SUFFERING FROM CONVECTIVE FEEDBACK...BUT WILL KEEP
SCT POPS IN ACROSS THE NORTH OVERNIGHT. IF THE COMPLEX DOES INDEED
DEVELOP...POPS MAY HAVE TO BE RAISED.

FRONT OVER THE MID ATLANTIC WILL SHIFT SOUTHWARD THROUGH MONDAY AND
CONTINUE TO APPROACH THE CWFA FROM THE NORTH. GOOD SOUTHERLY FLOW
AHEAD OF THE BOUNDARY AND INSTABILITY WILL LEAD TO ANOTHER DAY OF
SCT THUNDERSTORMS. SEVERE WEATHER IS NOT ANTICIPATED TODAY OR
MONDAY...BUT A FEW OF THE STORMS COULD BE STRONG. IN ADDITION...
LOCALLY HEAVY RAINFALL ACROSS NORTHERN GA WILL BE POSSIBLE
ESPECIALLY ON MONDAY. STORMS WILL ALSO BE CAPABLE OF PRODUCING
OCCASIONAL LIGHTNING STRIKES AND GUSTY WINDS.

NLISTEMAA

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...
12Z UPDATE...
ENHANCED FOG CHANNEL SHOWS A STRIP OF 300 TO 500 FOOT CIGS FROM
CANTON TO WEST OF ATL. THIS AREA IS MOVING EAST. DON`T THINK THE
DECK WILL DISSIPATE BEFORE IT REACHES THE AIRPORT...SO WILL
INCLUDE A BKN005 DECK FOR TWO HOURS. THE LOW DECK WILL SCT OUT TO
A CU DECK AROUND 4500 FT LATE THIS MORNING. CONVECTION HAS BEEN
INCREASING ACROSS N GA THIS MORNING. LATEST RUN OF THE HRRR HAS
THIS ACTIVITY COMING THROUGH THE AIRPORT AROUND 18Z. MOVED UP THE
PRECIP TIMING.

//ATL CONFIDENCE...12Z UPDATE...
LOW-MEDIUM CONFIDENCE ON LOW STRATUS CIGS THROUGH 15Z. MEDIUM
CONFIDENCE ON CONVECTION TIMING TODAY. OTHERWISE...HIGH CONFIDENCE
REMANING ELEMENTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  71  91  72 /  50  40  40  30
ATLANTA         89  72  89  74 /  50  40  40  40
BLAIRSVILLE     83  67  82  68 /  60  30  60  40
CARTERSVILLE    89  71  90  71 /  60  40  40  40
COLUMBUS        92  73  91  74 /  60  50  40  30
GAINESVILLE     88  71  88  73 /  60  40  40  40
MACON           91  72  91  72 /  60  50  40  30
ROME            88  71  92  72 /  60  30  60  40
PEACHTREE CITY  90  70  90  71 /  50  40  40  30
VIDALIA         91  74  91  74 /  60  40  40  30

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...ATWELL
LONG TERM....30
AVIATION...ATWELL






AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 1041 AM EDT SUN SEP 1 2013

.SYNOPSIS...
WEAK ATLANTIC HIGH PRESSURE WILL RESIDE OVER THE AREA THROUGH MONDAY.
A COLD FRONT WILL PUSH THROUGH TUESDAY NIGHT AND WEDNESDAY WITH WEAK
CANADIAN HIGH PRESSURE BUILDING IN FROM THE NORTH. THE HIGH WILL SHIFT
OFF THE COAST LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATE THIS MORNING...THE LACK OF ANY FOG/STRATUS HAS RESULTED IN
CLEAR SKIES ACROSS THE FORECAST AREA. THIS IS ALLOWING TEMPS TO
WARM QUITE RAPIDLY AND SOME AREAS ALREADY IN THE MID 80S. A CU
FIELD SHOULD START DEVELOPING VERY SOON AND WILL ENCOMPASS THE
ENTIRE FORECAST AREA. THE MAIN FORECAST ISSUE FOR TODAY REVOLVES
AROUND THE COVERAGE AND INTENSITY OF DIURNAL CONVECTION. THE
MODELS ACROSS THE SPECTRUM ARE SENDING MIXED SIGNALS. SOME OF THE
HI-RES RUNS SUCH AS THE HRRR SHOW LITTLE MORE THAN ISOLATED WEAK
CONVECTION. ON THE OTHER HAND...THE 12Z NAM HAS COME IN WITH AN
UPWARD TREND IN ITS COVERAGE AND INTENSITY. CURRENTLY...THERE IS A
WELL DEFINED AREA OF NVA ALOFT NOTED ON WATER VAPOR IMAGERY IN
ADVANCE OF THE POTENT SHORTWAVE DRIVING ONGOING CONVECTION OVER
THE TENNESSEE VALLEY. THIS NVA WILL LIKELY HANG ON UNTIL LATE IN
THE AFTERNOON BEFORE THE UPSTREAM ENERGY DISRUPTS IT. ANOTHER
INTERESTING NOTE CONCERNS THE THERMODYNAMIC PARAMETERS FROM THE
MODIFIED 12Z RAOB. USING A TEMP/DP OF SOMETHING AROUND 92/73
RESULTS IN CAPE VALUES AROUND 3000 J/KG...WITH DCAPES GREATER THAN
1000 J/KG THANKS TO A GOOD DEAL OF DRY MID LEVEL AIR. THE MAIN
SOURCE OF LOW LEVEL CONVERGENCE WILL BE THE SEA BREEZE...THE BEST
CONSENSUS SEEMS TO FAVOR ISOLATED TO SCATTERED COVERAGE IN THE
MID/LATE AFTERNOON HOURS. GIVEN THE NEAR STORM ENVIRONMENT...THIS
SEEMS TO BE A DAY WITH LIMITED COVERAGE BUT THE POTENTIAL FOR A
COUPLE STRONG TO SEVERE STORMS DEPENDING ON HOW THE SEA BREEZE AND
OUTFLOW BOUNDARIES INTERACT. AS I SAID EARLIER...TEMPS ARE RISING
QUICKLY AND WITH INCREASED LOW LEVEL THICKNESSES...HIGHS WILL BE
IN THE LOW 90S. SUCH VALUES WILL RUN ABOUT 4-5 DEGREES ABOVE CLIMO
FOR EARLY SEPTEMBER.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
TONIGHT...MOST AREAS LIKELY TO SEE DRY WEATHER. THE AREA WHERE SOME
ISOLATED NOCTURNAL CONVECTION MAY CROP UP OVERNIGHT COULD BE IN
THE SAME AREAS BORDERING THE MIDLANDS AND PEE DEE WHERE A BIT MORE
MID LEVEL TROFFINESS IS NOTED. COASTAL AREAS WILL KEEP A SLIGHT SW
BREEZE GOING OVERNIGHT AS PATTERN IS FAVORABLE FOR NOCTURNAL
JETTING ALONG THE SOUTH CAROLINA COAST.

A BROAD UPPER TROUGH WILL SIT OVER THE AREA ON MONDAY WITH
SUBSTANTIAL WESTERLY FLOW IN THE LOWER LEVELS. A WELL-DEFINED LEE
TROUGH COMBINED WITH MODEST SURFACE BASED CAPE SHOULD ALLOW FOR
SCATTERED SHOWERS/TSTMS ACROSS INLAND AREAS BY EARLY AFTERNOON.
THE SEABREEZE WILL BE PINNED NEAR THE COAST MUCH OF THE DAY BUT
COULD BECOME A PLAYER LATER IN THE AFTERNOON AS IT STARTS TO NUDGE
INLAND. WESTERLY STEERING FLOW SHOULD BRING INLAND CONVECTION
TOWARD THE COAST AS THE DAY PROGRESSES. OUR BEST COVERAGE LOOKS TO
BE LATE AFTERNOON INTO THE EVENING THOUGH A FEW STORMS COULD
CONTINUE OVERNIGHT GIVEN SUCH A RICH AIRMASS IN PLACE.

THE UPPER TROUGH WILL DEEPEN OVER THE EASTERN UNITED STATES ON
TUESDAY WITH A COLD FRONT SLOWLY DROPPING SOUTHEAST TOWARD THE AREA.
DEWPOINTS RISING INTO THE MIDDLE 70S WITH TEMPS PUSHING INTO THE
LOWER 90S WILL YIELD SUBSTANTIAL SURFACE BASED CAPES RANGING FROM
2000 TO 3000 J/KG. ADDITIONALLY SHORTWAVE ENERGY WILL PUSH IN FROM
THE WEST DURING THE AFTERNOON. THUS FAIRLY GOOD COVERAGE OF SHOWERS
AND TSTMS EXPECTED DURING THE DAY TUESDAY...ESPECIALLY LATER IN THE
AFTERNOON ONCE THE CONVECTIVE BOUNDARIES BEGIN INTERACTING WITH THE
SEABREEZE.

SCATTERED CONVECTION MAY CONTINUE INTO TUESDAY NIGHT BEFORE TAPERING
OFF FROM NORTH TO SOUTH. THE FRONT SHOULD PUSH SOUTH OF THE AREA ON
WEDNESDAY WITH SLIGHTLY DRIER AND COOLER CONDITIONS IN ITS WAKE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
CANADIAN HIGH PRESSURE WILL PREVAIL FOR THE BEGINNING OF THE PERIOD
BUT STEADILY SHIFT EAST WITH A RETURN FLOW SETTING UP ON THE SW
PERIPHERY. MOST AREAS WILL BE DRY WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT. DIURNAL CONVECTION RETURNS TO THE FORECAST FRIDAY THROUGH
SUNDAY AS LOW-LEVEL MOISTURE INCREASES AND ANOTHER UPPER TROUGH SETS
UP SHOP.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
STANDARD LATE SUMMER TAF FARE THIS MORNING. ATMOSPHERIC ENVIRONMENT
FAVORS ISOLATED/SCATTERED SHOWERS AND TSTMS THIS AFTERNOON IN A
MAINLY PULSE-TYPE CONVECTION MODE ANCHORED ON VARIOUS MESOSCALE
BOUNDARIES ACROSS THE COASTAL CORRIDOR. BY EARLY EVENING...THE
CONVECTION SHOULD DIMINISH WILL MAINLY VFR CONDITIONS CONTINUING
TONIGHT. A SW LOW LEVEL JET SHOULD PRECLUDE ANY RISK FOR FOG.

EXTENDED AVIATION OUTLOOK...SCATTERED SHOWERS AND TSTMS MONDAY
THROUGH TUESDAY NIGHT WITH OCCASIONAL REDUCTIONS IN CEILING AND
VISIBILITY.

&&

.MARINE...
SW FLOW SURGED A BIT OVERNIGHT...INTO THE 15 KT RANGE AT PLACES
SUCH AS FOLLY BEACH AND GRAYS REEF. THIS NOCTURNAL SURGE SHOULD
EBB NEARING DAYBREAK WITH FAIRLY LIGHT WINDS AND SEAS 2 TO 3 FT
THROUGH MUCH OF THE MORNING AND EARLY AFTERNOON HOURS. A STRONGER
NOCTURNAL SURGE IS ANTICIPATED TONIGHT AS THE BOUNDARY LAYER PRES
GRADIENT TIGHTENS. THERE MAY BE A SHORT DURATION WHERE WINDS
APPROACH SMALL CRAFT ADVISORY CONDITIONS IN FREQUENT GUSTS OVER
20 KT BUT WE HAVE CAPPED OFFSHORE FLOW AT 15 TO 20 KT FOR NOW.
SEAS WILL BUILD TO NEAR 4 FT BEYOND 20 NM OFFSHORE.

MONDAY THROUGH FRIDAY...WEATHER CONDITIONS WILL REMAIN BELOW
ADVISORY CRITERIA. SOUTH TO SOUTHWEST WINDS WILL PERSIST UNTIL
TUESDAY AHEAD OF THE COLD FRONT. ONCE THE FRONT PUSHES INTO THE
AREA...WINDS WILL BECOME VARIABLE AND LIGHT...WITH SEAS NO HIGHER
THAN 2-3 FEET.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...BSH
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL





AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 954 AM EDT SUN SEP 1 2013

.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE COAST WILL DIRECT A MOIST SOUTH
FLOW INTO THE FORECAST AREA THROUGH MONDAY. A SLOW MOVING COLD
FRONT WILL MOVE INTO THE AREA TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NVA COVERS THE REGION THIS MORNING WITH NO ACTIVITY IN THE FA
SO FAR. AN UPSTREAM SHORT WAVE HAS KICKED OFF SOME SHOWER AND
THUNDERSTORM ACTIVITY ACROSS NORTHERN GEORGIA. THE RUC MODEL
MOVES THIS FEATURE INTO UPSTATE SOUTH CAROLINA LATER THIS
AFTERNOON. EXPECT CONDITIONS TO REMAIN QUIET THROUGH THE MORNING
HOURS. THEN AS AFTERNOON LAPSE RATES STEEPEN...MODEL LIS LOWER
TO -6...CAPES GET OVER 2000 J/KG AND PWAT VALUES REMAIN HIGH
AROUND 1.70 INCHES. SO WILL GO WITH A 30 PERCENT CHANCE NORTH
CLOSER TO THE SHORT WAVE AND A 20 PERCENT CHANCE CENTRAL AND
SOUTH PARTS. HIGH TEMPERATURES WITH SOME SUNSHINE SHOULD REACH
90 WITH MANY LOCATIONS GETTING TO ABOUT 91.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE MODELS HINT AT A WEAK SURFACE TROUGH LINGERING IN THE
FORECAST AREA THROUGH MONDAY. THE MODEL TIME SECTIONS INDICATE
INCREASING MOISTURE THROUGH THE PERIOD AHEAD OF THE SLOW MOVING
COLD FRONT. THERE WILL BE A SERIES OF MID-LEVEL SHORTWAVE TROUGHS
THAT WILL DEEPEN THE TROUGH ALONG THE EAST COAST THROUGH THE
PERIOD. THE MODELS AND ENSEMBLES INDICATE SLIGHT CHANCE/CHANCE
POPS THROUGH TUESDAY. THE GREATEST CHANCE FOR SHOWERS AND
THUNDERSTORMS APPEARS TO BE JUST AHEAD OF THE FRONT TUESDAY.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BASED ON RECENT
VERIFICATION AND EXPECTED CLOUDINESS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE GFS AND ECMWF SHOW THE COLD FRONT IN THE FORECAST AREA
TUESDAY NIGHT WITH THE FRONT STALLING NEAR THE COAST WEDNESDAY.
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA BY TUESDAY NIGHT
AS THE MAIN MID-LEVEL SHORTWAVE TROUGHS MOVES OFF THE COAST. THE
MODELS INDICATE AN INVERTED TROUGH SHIFTING INLAND BEGINNING
FRIDAY BUT MOISTURE APPEARS LIMITED. THE GFS AND ECMWF MOS INDICATE
POPS MAINLY AROUND 20 PERCENT WHICH AGREES WITH THE GFS ENSEMBLE
MEANS. EXPECT TEMPERATURES NEAR CLIMATOLOGY.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE CENTERED OFF THE ATLANTIC COAST WILL CONTINUE TO
PROVIDE A MOIST FLOW OVER THE FORECAST AREA TODAY. MVFR/IFR
CONDITIONS ACROSS THE AREA THIS MORNING WILL IMPROVE TO VFR BY
AROUND 15Z. ISOLATED SHOWERS PERSIST EARLY THIS MORNING...BUT MAIN
ACTIVITY IS ACROSS EASTERN TN/NRN GA INTO WRN NC. DIURNALLY DRIVEN
SCATTERED SHOWERS/TSTMS EXPECTED TO DEVELOP LATE THIS AFTERNOON
CONTINUE WELL INTO THE EVENING.

EXTENDED AVIATION OUTLOOK...AFTERNOON CONVECTION IS EXPECTED TO
INCREASE IN COVERAGE MON/TUE WITH THE NEXT FRONT MOVING INTO THE
AREA.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$







AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 822 AM EDT SUN SEP  1 2013

.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE COAST WILL DIRECT A MOIST SOUTH
FLOW INTO THE FORECAST AREA THROUGH MONDAY. A SLOW MOVING COLD
FRONT WILL MOVE INTO THE AREA TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A MID-LEVEL SHORTWAVE TROUGH WAS HELPING TO SUPPORT ISOLATED
SHOWERS IN THE NORTH PART EARLY THIS MORNING. LIFT ASSOCIATED WITH
THIS FEATURE WILL LIKELY BE EAST OF THE AREA BY AFTERNOON BUT
ANOTHER SHORTWAVE TROUGH MAY MOVE INTO THE AREA LATE THIS
AFTERNOON. THE LATEST RAP SHOWED THE LATER TROUGH REACHING THE
AREA AROUND 21Z. THE HIGH-RESOLUTION MODELS SUGGESTED SCATTERED
COVERAGE AND AN AVERAGE OF THE GFS AND NAM MOS SUPPORTED CHANCE
POPS. THE LIMITED COVERAGE APPEARED REASONABLE BECAUSE OF SOMEWHAT
SHALLOW MOISTURE AND WEAK LIFT. CLOUDINESS SHOULD HELP HOLD DOWN
TEMPERATURES. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE MODELS HINT AT A WEAK SURFACE TROUGH LINGERING IN THE
FORECAST AREA THROUGH MONDAY. THE MODEL TIME SECTIONS INDICATE
INCREASING MOISTURE THROUGH THE PERIOD AHEAD OF THE SLOW MOVING
COLD FRONT. THERE WILL BE A SERIES OF MID-LEVEL SHORTWAVE TROUGHS
THAT WILL DEEPEN THE TROUGH ALONG THE EAST COAST THROUGH THE
PERIOD. THE MODELS AND ENSEMBLES INDICATE SLIGHT CHANCE/CHANCE
POPS THROUGH TUESDAY. THE GREATEST CHANCE FOR SHOWERS AND
THUNDERSTORMS APPEARS TO BE JUST AHEAD OF THE FRONT TUESDAY.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BASED ON RECENT
VERIFICATION AND EXPECTED CLOUDINESS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE GFS AND ECMWF SHOW THE COLD FRONT IN THE FORECAST AREA
TUESDAY NIGHT WITH THE FRONT STALLING NEAR THE COAST WEDNESDAY.
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA BY TUESDAY NIGHT
AS THE MAIN MID-LEVEL SHORTWAVE TROUGHS MOVES OFF THE COAST. THE
MODELS INDICATE AN INVERTED TROUGH SHIFTING INLAND BEGINNING
FRIDAY BUT MOISTURE APPEARS LIMITED. THE GFS AND ECMWF MOS INDICATE
POPS MAINLY AROUND 20 PERCENT WHICH AGREES WITH THE GFS ENSEMBLE
MEANS. EXPECT TEMPERATURES NEAR CLIMATOLOGY.

&&

.AVIATION /12Z SUNDAY THROUGH FRIDAY/...
HIGH PRESSURE CENTERED OFF THE ATLANTIC COAST WILL CONTINUE TO
PROVIDE A MOIST FLOW OVER THE FORECAST AREA TODAY. MVFR/IFR
CONDITIONS ACROSS THE AREA THIS MORNING WILL IMPROVE TO VFR BY
AROUND 15Z. ISOLATED SHOWERS PERSIST EARLY THIS MORNING...BUT MAIN
ACTIVITY IS ACROSS EASTERN TN/NRN GA INTO WRN NC. DIURNALLY DRIVEN
SCATTERED SHOWERS/TSTMS EXPECTED TO DEVELOP LATE THIS AFTERNOON
CONTINUE WELL INTO THE EVENING.

EXTENDED AVIATION OUTLOOK...AFTERNOON CONVECTION IS EXPECTED TO
INCREASE IN COVERAGE MON/TUE WITH THE NEXT FRONT MOVING INTO THE
AREA.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$






AREA FORECAST DISCUSSION

NWS PEACHTREE CITY GA

 746 AM EDT SUN SEP 1 2013



.UPDATE...
HAVE UPPED THE POPS ACROSS NORTHERN GA THIS MORNING. HAVE SEEN A
STEADY INCREASE IN COVERAGE AHEAD OF WEAKENING MCS.

&&

.PREV DISCUSSION... /ISSUED 324 AM EDT SUN SEP 1 2013/

SHORT TERM /TODAY THROUGH MONDAY/...
HIGH PRESSURE HAS MOVED OFFSHORE...WHILE A STALLED BOUNDARY
REMAINS SITUATED ACROSS THE OHIO VALLEY. REGIONAL RADAR AND
SATELLITE SHOWS A WEAKENING MCS DROPPING SOUTH ACROSS SOUTHERN IN
AND W KY. ANOTHER AREA OF WEAKENING STORMS IS ACROSS THE TN/NC
BORDER. JUST A FEW CLOUDS ACROSS THE CWFA THIS MORNING...BLOW OFF
FROM THE STORMS TO THE NORTH. PATCHY FOG HAS ALSO DEVELOPED BUT
SHOULD BEGIN TO BURN OFF AFTER SUNRISE.

THE LATEST RUN OF THE HRRR BRINGS THE REMNANT SHOWERS/
THUNDERSTORMS FROM THE COMPLEXES UP NORTH ACROSS NORTHERN GA
DURING THE FIRST PART OF THE MORNING. THIS SEEMS REASONABLE...AS
THE ACTIVITY SHOULD CONTINUE TO WEAKEN AS IT APPROACHES THE
NORTHERN METRO. DO THINK THAT STORMS LATER IN THE DAY COULD FOCUS
UPON THE LEFTOVER OUTFLOW/DIFFERENTIAL HEATING BOUNDARY. HAVE
TRIED TO ORIENT POPS ACCORDING TO THE EARLY HOURS OF THE HRRR
OUTPUT.

MODELS DO HAVE A WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW ACROSS
NORTHERN GA LATER IN THE AFTERNOON. THIS FEATURE SHOULD SERVE TO
FOCUS/INITIATE SCT/NMRS STORMS INTO THE EARLY EVENING. MODELS KEEP
THE ATMOS UNSTABLE OVERNIGHT...AND WITH ABUNDANT LOW LEVEL
MOISTURE...SCT/ISO STORMS WILL BE POSSIBLE THROUGH THE OVERNIGHT
HOURS. TOWARDS 12Z MONDAY...THE GFS LOOKS AS IF IT IS TRYING TO
BRING AN MCS ACROSS NORTHERN GA. THE NAM DOESN`T REALLY HAVE THIS
FEATURE IN THE MID LEVELS OR THE 800MB - 300MB THICKNESS PATTERN.
THE GFS MAY BE SUFFERING FROM CONVECTIVE FEEDBACK...BUT WILL KEEP
SCT POPS IN ACROSS THE NORTH OVERNIGHT. IF THE COMPLEX DOES INDEED
DEVELOP...POPS MAY HAVE TO BE RAISED.

FRONT OVER THE MID ATLANTIC WILL SHIFT SOUTHWARD THROUGH MONDAY AND
CONTINUE TO APPROACH THE CWFA FROM THE NORTH. GOOD SOUTHERLY FLOW
AHEAD OF THE BOUNDARY AND INSTABILITY WILL LEAD TO ANOTHER DAY OF
SCT THUNDERSTORMS. SEVERE WEATHER IS NOT ANTICIPATED TODAY OR
MONDAY...BUT A FEW OF THE STORMS COULD BE STRONG. IN ADDITION...
LOCALLY HEAVY RAINFALL ACROSS NORTHERN GA WILL BE POSSIBLE
ESPECIALLY ON MONDAY. STORMS WILL ALSO BE CAPABLE OF PRODUCING
OCCASIONAL LIGHTNING STRIKES AND GUSTY WINDS.

NLISTEMAA

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...
12Z UPDATE...
ENHANCED FOG CHANNEL SHOWS A STRIP OF 300 TO 500 FOOT CIGS FROM
CANTON TO WEST OF ATL. THIS AREA IS MOVING EAST. DON`T THINK THE
DECK WILL DISSIPATE BEFORE IT REACHES THE AIRPORT...SO WILL
INCLUDE A BKN005 DECK FOR TWO HOURS. THE LOW DECK WILL SCT OUT TO
A CU DECK AROUND 4500 FT LATE THIS MORNING. CONVECTION HAS BEEN
INCREASING ACROSS N GA THIS MORNING. LATEST RUN OF THE HRRR HAS
THIS ACTIVITY COMING THROUGH THE AIRPORT AROUND 18Z. MOVED UP THE
PRECIP TIMING.

//ATL CONFIDENCE...12Z UPDATE...
LOW-MEDIUM CONFIDENCE ON LOW STRATUS CIGS THROUGH 15Z. MEDIUM
CONFIDENCE ON CONVECTION TIMING TODAY. OTHERWISE...HIGH CONFIDENCE
REMANING ELEMENTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  71  91  72 /  40  40  40  30
ATLANTA         89  72  89  74 /  40  40  40  40
BLAIRSVILLE     83  67  82  68 /  60  50  60  40
CARTERSVILLE    90  71  90  71 /  50  50  40  40
COLUMBUS        92  73  91  74 /  40  30  40  30
GAINESVILLE     88  71  88  73 /  40  50  40  40
MACON           91  72  91  72 /  40  30  40  30
ROME            91  71  92  72 /  60  50  60  40
PEACHTREE CITY  90  70  90  71 /  40  40  40  30
VIDALIA         91  74  91  74 /  40  30  40  30

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 623 AM EDT SUN SEP 1 2013

.SYNOPSIS...
HIGH PRESSURE CENTERED OFF THE COAST WILL DIRECT A MOIST SOUTH
FLOW INTO THE FORECAST AREA THROUGH MONDAY. A SLOW MOVING COLD
FRONT WILL MOVE INTO THE AREA TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A MID-LEVEL SHORTWAVE TROUGH WAS HELPING TO SUPPORT ISOLATED
SHOWERS IN THE NORTH PART EARLY THIS MORNING. LIFT ASSOCIATED WITH
THIS FEATURE WILL LIKELY BE EAST OF THE AREA BY AFTERNOON BUT
ANOTHER SHORTWAVE TROUGH MAY MOVE INTO THE AREA LATE THIS
AFTERNOON. THE LATEST RAP SHOWED THE LATER TROUGH REACHING THE
AREA AROUND 21Z. THE HIGH-RESOLUTION MODELS SUGGESTED SCATTERED
COVERAGE AND AN AVERAGE OF THE GFS AND NAM MOS SUPPORTED CHANCE
POPS. THE LIMITED COVERAGE APPEARED REASONABLE BECAUSE OF SOMEWHAT
SHALLOW MOISTURE AND WEAK LIFT. CLOUDINESS SHOULD HELP HOLD DOWN
TEMPERATURES. LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE MODELS HINT AT A WEAK SURFACE TROUGH LINGERING IN THE
FORECAST AREA THROUGH MONDAY. THE MODEL TIME SECTIONS INDICATE
INCREASING MOISTURE THROUGH THE PERIOD AHEAD OF THE SLOW MOVING
COLD FRONT. THERE WILL BE A SERIES OF MID-LEVEL SHORTWAVE TROUGHS
THAT WILL DEEPEN THE TROUGH ALONG THE EAST COAST THROUGH THE
PERIOD. THE MODELS AND ENSEMBLES INDICATE SLIGHT CHANCE/CHANCE
POPS THROUGH TUESDAY. THE GREATEST CHANCE FOR SHOWERS AND
THUNDERSTORMS APPEARS TO BE JUST AHEAD OF THE FRONT TUESDAY.
LEANED TOWARD THE COOLER TEMPERATURE GUIDANCE BASED ON RECENT
VERIFICATION AND EXPECTED CLOUDINESS.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE GFS AND ECMWF SHOW THE COLD FRONT IN THE FORECAST AREA
TUESDAY NIGHT WITH THE FRONT STALLING NEAR THE COAST WEDNESDAY.
DEEPER MOISTURE APPEARS TO SHIFT EAST OF THE AREA BY TUESDAY NIGHT
AS THE MAIN MID-LEVEL SHORTWAVE TROUGHS MOVES OFF THE COAST. THE
MODELS INDICATE AN INVERTED TROUGH SHIFTING INLAND BEGINNING
FRIDAY BUT MOISTURE APPEARS LIMITED. THE GFS AND ECMWF MOS INDICATE
POPS MAINLY AROUND 20 PERCENT WHICH AGREES WITH THE GFS ENSEMBLE
MEANS. EXPECT TEMPERATURES NEAR CLIMATOLOGY.

&&

.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE CENTERED OFF THE ATLANTIC COAST WILL CONTINUE TO
PROVIDE A MOIST FLOW OVER THE FORECAST AREA TODAY. MVFR/IFR
CONDITIONS ACROSS THE AREA THIS MORNING WILL IMPROVE TO VFR BY
AROUND 15Z. ISOLATED SHOWERS PERSIST EARLY THIS MORNING BUT ARE NOT
EXPECTED TO AFFECT ANY OF THE TAF SITES. DIURNALLY DRIVEN SCATTERED
SHOWERS/TSTMS EXPECTED TO DEVELOP LATE THIS AFTERNOON CONTINUE
WELL INTO THE EVENING.

EXTENDED AVIATION OUTLOOK...AFTERNOON CONVECTION IS EXPECTED TO
INCREASE IN COVERAGE MON/TUE WITH THE NEXT FRONT MOVING INTO THE
AREA.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&

$$







AREA FORECAST DISCUSSION

NWS PEACHTREE CITY GA

 324 AM EDT SUN SEP 1 2013

.SHORT TERM /TODAY THROUGH MONDAY/...
HIGH PRESSURE HAS MOVED OFFSHORE...WHILE A STALLED BOUNDARY
REMAINS SITUATED ACROSS THE OHIO VALLEY. REGIONAL RADAR AND
SATELLITE SHOWS A WEAKENING MCS DROPPING SOUTH ACROSS SOUTHERN IN
AND W KY. ANOTHER AREA OF WEAKENING STORMS IS ACROSS THE TN/NC
BORDER. JUST A FEW CLOUDS ACROSS THE CWFA THIS MORNING...BLOW OFF
FROM THE STORMS TO THE NORTH. PATCHY FOG HAS ALSO DEVELOPED BUT
SHOULD BEGIN TO BURN OFF AFTER SUNRISE.

THE LATEST RUN OF THE HRRR BRINGS THE REMNANT SHOWERS/
THUNDERSTORMS FROM THE COMPLEXES UP NORTH ACROSS NORTHERN GA
DURING THE FIRST PART OF THE MORNING. THIS SEEMS REASONABLE...AS
THE ACTIVITY SHOULD CONTINUE TO WEAKEN AS IT APPROACHES THE
NORTHERN METRO. DO THINK THAT STORMS LATER IN THE DAY COULD FOCUS
UPON THE LEFTOVER OUTFLOW/DIFFERENTIAL HEATING BOUNDARY. HAVE
TRIED TO ORIENT POPS ACCORDING TO THE EARLY HOURS OF THE HRRR
OUTPUT.

MODELS DO HAVE A WEAK SHORTWAVE DROPPING SOUTH IN THE FLOW ACROSS
NORTHERN GA LATER IN THE AFTERNOON. THIS FEATURE SHOULD SERVE TO
FOCUS/INITIATE SCT/NMRS STORMS INTO THE EARLY EVENING. MODELS KEEP
THE ATMOS UNSTABLE OVERNIGHT...AND WITH ABUNDANT LOW LEVEL
MOISTURE...SCT/ISO STORMS WILL BE POSSIBLE THROUGH THE OVERNIGHT
HOURS. TOWARDS 12Z MONDAY...THE GFS LOOKS AS IF IT IS TRYING TO
BRING AN MCS ACROSS NORTHERN GA. THE NAM DOESN`T REALLY HAVE THIS
FEATURE IN THE MID LEVELS OR THE 800MB - 300MB THICKNESS PATTERN.
THE GFS MAY BE SUFFERING FROM CONVECTIVE FEEDBACK...BUT WILL KEEP
SCT POPS IN ACROSS THE NORTH OVERNIGHT. IF THE COMPLEX DOES INDEED
DEVELOP...POPS MAY HAVE TO BE RAISED.

FRONT OVER THE MID ATLANTIC WILL SHIFT SOUTHWARD THROUGH MONDAY AND
CONTINUE TO APPROACH THE CWFA FROM THE NORTH. GOOD SOUTHERLY FLOW
AHEAD OF THE BOUNDARY AND INSTABILITY WILL LEAD TO ANOTHER DAY OF
SCT THUNDERSTORMS. SEVERE WEATHER IS NOT ANTICIPATED TODAY OR
MONDAY...BUT A FEW OF THE STORMS COULD BE STRONG. IN ADDITION...
LOCALLY HEAVY RAINFALL ACROSS NORTHERN GA WILL BE POSSIBLE
ESPECIALLY ON MONDAY. STORMS WILL ALSO BE CAPABLE OF PRODUCING
OCCASIONAL LIGHTNING STRIKES AND GUSTY WINDS.

NLISTEMAA

.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...
PATCHY FOG HAS DEVELOPED AT QUITE A FEW OF THE TERMINAL SITES THIS
MORNING. FOR THE NORTHERN TERMINAL SITES...VSBYS/CIGS SHOULD
REMAIN IN THE MVFR RANGE. EVEN ATL HAS A CHANCE AT 4SM AND BKN012
AFTER RECEIVING RAINFALL TODAY. MCN WILL HAVE THE BEST CHANCE AT
SEEING 1/2SM IN FG TOWARDS SUNRISE. BKN DIURNAL CU BTWN 040 AND
050 EXPECTED TODAY. BEST TIMES FOR CONVECTION ARE BETWEEN 19Z AND
01Z. LOW CIGS A POSSIBILITY FOR OVERNIGHT SUN/EARLY MON.

//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON CIGS/VSBYS THROUGH 13Z. OTHERWISE...HIGH
CONFIDENCE ALL ELEMENTS.

NLISTEMAA

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          89  70  90  70 /  50  40  40  40
ATLANTA         89  73  88  72 /  50  40  30  40
BLAIRSVILLE     83  66  84  65 /  60  50  50  30
CARTERSVILLE    90  70  89  70 /  50  50  40  50
COLUMBUS        92  74  90  74 /  40  30  30  20
GAINESVILLE     86  71  87  70 /  50  50  50  30
MACON           92  71  89  71 /  40  30  30  30
ROME            92  71  90  69 /  50  50  50  40
PEACHTREE CITY  88  71  89  70 /  50  40  30  30
VIDALIA         91  73  90  73 /  40  30  30  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...NLISTEMAA
LONG TERM....TDP
AVIATION...NLISTEMAA





AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 252 PM CDT SUN SEP 1 2013

.DISCUSSION...
1045 AM CDT

NO BIG CHANGES MADE TO GOING FORECAST OTHER THAN TO SLOW THE WARM UP
TREND IN HOURLY TEMPS THIS MORNING DUE TO CONSIDERABLE CLOUD COVER.
HAVE LEFT FORECAST HIGHS TEMPS LARGELY AS IS BANKING ON THE FACT
THAT THE FAIRLY HIGH SUN ANGLE SHOULD BE ENOUGH TO ERODE STRATUS AND
ALLOW FOR AT LEAST PARTIAL SUNSHINE AND A QUICK REBOUND IN TEMPS
DURING THE AFTERNOON.

CONVECTIVE CHANCES AND SEVERE POTENTIAL ARE A BIT MORE MURKY. FRONT
THAT PASSED SOUTH OF THE AREA EARLIER THIS WEEKEND TOOK SOME OF THE
MOISTURE WITH IT...THOUGH SURFACE OBS DO SHOW A SMALL RIBBON OF
HIGHER DEWPOINTS BEGINNING TO POOL IN ADVANCE OF THE SECOND AND
STRONGER FRONT THAT WILL MOVE THROUGH LATER TODAY. FRONTAL
CONVERGENCE LOOKS TO BE FAIRLY WEAK WITH SFC WINDS ALL VEERED TO THE
WEST ALREADY AHEAD OF THE FRONT WITH LOW LEVEL MASS CONVERGENCE
BASICALLY JUST SPEED CONVERGENCE WITH STRONGER NORTHWEST WINDS
BEHIND THE FRONT. WATER VAPOR IMAGERY DOES SHOW A SHORTWAVE
ASSOCIATED WITH A SPEED MAX MOVING INTO SOUTHERN MN AND JUST NOW
INTO FAR NORTHERN IOWA THIS MORNING. LARGE SCALE ASCENT IN ADVANCE
THIS FEATURE WILL BE KEY IN THE CONVECTIVE POTENTIAL THIS AFTERNOON
GIVEN THE PALTRY LOW LEVEL CONVERGENCE AND STOUT CAPPING INVERSION
NOTED ON THE 1200 UTC KDVN/KILX SOUNDINGS.

BOTH SOUNDINGS DID SHOW A FAIRLY CLASSIC LOAD GUN TYPE SET UP WITH
STEEP LAPSE RATES LOCATED ABOVE A MOIST BOUNDARY LAYER. ASSUMING
THAT WE ARE ABLE TO HEAT UP AS EXPECTED THIS AFTERNOON THEN MLCAPES
WOULD LIKELY CLIMB ABOVE 2000 J/KG WITH FORECAST RAP SOUNDINGS
SUGGESTING THAT THE CAP WILL BE EFFECTIVELY LIFTED THROUGH WITH
MINIMAL INHIBITION. FAIRLY STOUT 6KM WEST-NORTHWEST WINDS OF 30-35KT
HAVE BEEN SAMPLED UPSTREAM AND ARE PROGGED TO BE OVER THE AREA THIS
AFTERNOON. HOWEVER...LIGHT WESTERLY WINDS AT THE SFC WILL RESULT IN
BULK SHEAR VALUES OF ONLY 25-30KT...WHICH GIVEN MODERATE INSTABILITY
WOULD BE ENOUGH TO ALLOW FOR SOME DEGREE OF STORM ORGANIZATION AND
RESULTANT SEVERE THREAT...PRIMARILY IN THE FORM OF DAMAGING WINDS.
OF COURSE THIS IS ALL CONTINGENT ON SUFFICIENT INSTABILITY ACTUALLY
BEING REALIZED AND THEN STORMS FORMING DESPITE THE MEAGER LOW LEVEL
CONVERGENCE. GIVEN ALL THE UNCERTAINTIES HAVE OPTED TO MAINTAIN POPS
IN THE 40-50% RANGE THIS AFTERNOON INTO EARLY THIS EVENING SOUTHEAST
CWA.

WILL NEED TO WATCH FOR POTENTIAL LAKE BREEZE FORMATION RIGHT ALONG
THE SHORE THIS AFTERNOON GIVEN LIGHT SYNOPTIC WINDS. SHOULD LAKE
BREEZE FORM THE ENHANCED CONVERGENCE COULD BE A FOCAL POINT
CONVECTIVE INITIATION GIVEN THE RELATIVE ABSENCE OF LOW LEVEL
CONVERGENCE ELSEWHERE.

FORECAST GRIDS AND DERIVED PRODUCTS HAVE ALREADY BEEN SENT.

IZZI

//PREV DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GENERALLY WESTERLY WINDS TO ARND 10KT UNTIL FROPA EARLY THIS
  EVENING...THEN SHIFT NORTHWEST/NORTH AND STRENGTHENING OVERNIGHT
  FOLLOWING FRONTAL PASSAGE.

* NORTH WINDS GUSTING TO 18 KT BY THE EARLY MORNING HOURS.

* ISOLD SHRA/TSRA DEVELOPING ALONG OR JUST AHEAD OF THE FRONTAL
  BOUNDARY.

KREIN

//DISCUSSION...UPDATED 18Z...

PRIMARY CONCERN FOR THE PERIOD WILL BE THE CHANCES FOR SHRA/TSRA
LATE THIS AFTERNOON INTO EARLY THIS EVENING. A COLD FRONT IS
DROPPING SEWD INTO THE MIDDLE MISSISSIPPI VALLEY WHICH SHOULD BE
THE FOCUS FOR THE CONVECTIVE ACTIVITY. LATEST SFC ANALYSIS SHOWS A
FAIRLY DIFFUSE BOUNDARY WITH LITTLE WIND SHIFT OR TEMPERATURE
CONTRAST INVOF THE BOUNDARY WITH WINDS ONLY GRADUALLY VEERING FROM
WLY TO NWLY. EARLY MORNING STRATUS AND FOG HAS FINALLY CLEARED AND
INCREASED INSOLATION IS ALLOWING SFC TEMPS TO INCREASE INTO THE
80S WITH DEWPOINTS IN THE UPPER 60S TO LOWER 70S. LATEST VISIBLY
SATELLITE IMAGERY IS ALSO INDICATING ENHANCED CU DEVELOPMENT INVOF
THE FRONTAL BOUNDARY. STILL EXPECTING SCT SHOWERS AND
THUNDERSTORMS AS THE FRONT MOVES THROUGH THE AREA...BUT SINCE
CONVECTIVE ACTIVITY IS EXPECTED TO REMAIN SCATTERED...CONFIDENCE
IN EXACT TIMING AND DURATION IS LOW.

FOLLOWING THE FROPA...COOLER...DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION WITH THE STRONGEST COLD ADVECTION DEVELOPING
DURING THE EARLY MORNING HOURS. EXPECT THAT WINDS SHOULD VEER TO
NORTHERLY AND GUST TO ARND 18KT IN TIME FOR THE MORNING RUSH
HOURS. WINDS SHOULD GRADUALLY TAPER OFF THROUGH THE AFTERNOON
TOMORROW AS HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI
VALLEY AND INTO THE WESTERN GREAT LAKES.

KREIN

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEED.

* LOW CONFIDENCE IN TIMING AND COVERAGE OF SHRA/TSRA.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...VFR. NORTH/NORTHEAST WINDS.

TUESDAY THROUGH WEDNESDAY...VFR. AFTERNOON LAKE BREEZE.

THURSDAY THROUGH SATURDAY...VFR.

BEACHLER

&&

.MARINE...

252 PM...LOW PRESSURE OVER LAKE SUPERIOR WILL SLOWLY MOVE EAST
INTO QUEBEC MONDAY AFTERNOON. A TRAILING COLD FRONT WILL MOVE
SOUTH ACROSS LAKE MICHIGAN THIS EVENING SHIFTING WINDS BRIEFLY
NORTHWEST AND THEN NORTHERLY OVERNIGHT. PREVAILING SPEEDS IN THE
20-25KT RANGE STILL LOOK ON TRACK THOUGH ITS STILL POSSIBLE FOR
SOME GUSTS TO 30 KT ESPECIALLY MONDAY MORNING. HIGH PRESSURE WILL
BUILD ACROSS THE NORTHERN PLAINS TONIGHT INTO MONDAY AND THEN
SLIDE SOUTHEAST ACROSS THE SOUTHERN LAKES AND OHIO VALLEY MONDAY
NIGHT THROUGH WEDNESDAY. THIS WILL ALLOW THE WINDS TO DIMINISH
FIRST ACROSS THE SOUTHERN END OF THE LAKE BUT AS ANOTHER FRONT
SAGS INTO THE NORTHERN LAKES TUESDAY NIGHT INTO WEDNESDAY...THE
GRADIENT MAY STAY SOMEWHAT TIGHT ACROSS THE NORTHERN HALF OR THIRD
OF THE LAKE TUESDAY NIGHT INTO WEDNESDAY. HIGH PRESSURE SPREADING
ACROSS SOUTHERN CANADA TUESDAY NIGHT WILL WEAKEN AND MERGE WITH
THE HIGH OVER THE OHIO VALLEY WEDNESDAY AND WEDNESDAY NIGHT. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

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AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 102 PM CDT SUN SEP 1 2013

.DISCUSSION...
1045 AM CDT

NO BIG CHANGES MADE TO GOING FORECAST OTHER THAN TO SLOW THE WARM UP
TREND IN HOURLY TEMPS THIS MORNING DUE TO CONSIDERABLE CLOUD COVER.
HAVE LEFT FORECAST HIGHS TEMPS LARGELY AS IS BANKING ON THE FACT
THAT THE FAIRLY HIGH SUN ANGLE SHOULD BE ENOUGH TO ERODE STRATUS AND
ALLOW FOR AT LEAST PARTIAL SUNSHINE AND A QUICK REBOUND IN TEMPS
DURING THE AFTERNOON.

CONVECTIVE CHANCES AND SEVERE POTENTIAL ARE A BIT MORE MURKY. FRONT
THAT PASSED SOUTH OF THE AREA EARLIER THIS WEEKEND TOOK SOME OF THE
MOISTURE WITH IT...THOUGH SURFACE OBS DO SHOW A SMALL RIBBON OF
HIGHER DEWPOINTS BEGINNING TO POOL IN ADVANCE OF THE SECOND AND
STRONGER FRONT THAT WILL MOVE THROUGH LATER TODAY. FRONTAL
CONVERGENCE LOOKS TO BE FAIRLY WEAK WITH SFC WINDS ALL VEERED TO THE
WEST ALREADY AHEAD OF THE FRONT WITH LOW LEVEL MASS CONVERGENCE
BASICALLY JUST SPEED CONVERGENCE WITH STRONGER NORTHWEST WINDS
BEHIND THE FRONT. WATER VAPOR IMAGERY DOES SHOW A SHORTWAVE
ASSOCIATED WITH A SPEED MAX MOVING INTO SOUTHERN MN AND JUST NOW
INTO FAR NORTHERN IOWA THIS MORNING. LARGE SCALE ASCENT IN ADVANCE
THIS FEATURE WILL BE KEY IN THE CONVECTIVE POTENTIAL THIS AFTERNOON
GIVEN THE PALTRY LOW LEVEL CONVERGENCE AND STOUT CAPPING INVERSION
NOTED ON THE 1200 UTC KDVN/KILX SOUNDINGS.

BOTH SOUNDINGS DID SHOW A FAIRLY CLASSIC LOAD GUN TYPE SET UP WITH
STEEP LAPSE RATES LOCATED ABOVE A MOIST BOUNDARY LAYER. ASSUMING
THAT WE ARE ABLE TO HEAT UP AS EXPECTED THIS AFTERNOON THEN MLCAPES
WOULD LIKELY CLIMB ABOVE 2000 J/KG WITH FORECAST RAP SOUNDINGS
SUGGESTING THAT THE CAP WILL BE EFFECTIVELY LIFTED THROUGH WITH
MINIMAL INHIBITION. FAIRLY STOUT 6KM WEST-NORTHWEST WINDS OF 30-35KT
HAVE BEEN SAMPLED UPSTREAM AND ARE PROGGED TO BE OVER THE AREA THIS
AFTERNOON. HOWEVER...LIGHT WESTERLY WINDS AT THE SFC WILL RESULT IN
BULK SHEAR VALUES OF ONLY 25-30KT...WHICH GIVEN MODERATE INSTABILITY
WOULD BE ENOUGH TO ALLOW FOR SOME DEGREE OF STORM ORGANIZATION AND
RESULTANT SEVERE THREAT...PRIMARILY IN THE FORM OF DAMAGING WINDS.
OF COURSE THIS IS ALL CONTINGENT ON SUFFICIENT INSTABILITY ACTUALLY
BEING REALIZED AND THEN STORMS FORMING DESPITE THE MEAGER LOW LEVEL
CONVERGENCE. GIVEN ALL THE UNCERTAINTIES HAVE OPTED TO MAINTAIN POPS
IN THE 40-50% RANGE THIS AFTERNOON INTO EARLY THIS EVENING SOUTHEAST
CWA.

WILL NEED TO WATCH FOR POTENTIAL LAKE BREEZE FORMATION RIGHT ALONG
THE SHORE THIS AFTERNOON GIVEN LIGHT SYNOPTIC WINDS. SHOULD LAKE
BREEZE FORM THE ENHANCED CONVERGENCE COULD BE A FOCAL POINT
CONVECTIVE INITIATION GIVEN THE RELATIVE ABSENCE OF LOW LEVEL
CONVERGENCE ELSEWHERE.

FORECAST GRIDS AND DERIVED PRODUCTS HAVE ALREADY BEEN SENT.

IZZI

//PREV DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* WEST TO WEST-NORTHWEST WINDS TO ARND 10KT UNTIL FROPA LATE THIS
  AFTERNOON...THEN SHIFT NORTHWEST/NORTH AND STRENGTHENING
  FOLLOWING FRONTAL PASSAGE.

* NORTH WINDS GUSTING TO 18KT BY THE EARLY MORNING HOURS.

* ISOLD SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY.

KREIN

//DISCUSSION...UPDATED 18Z...

PRIMARY CONCERN FOR THE PERIOD WILL BE THE CHANCES FOR SHRA/TSRA
LATE THIS AFTERNOON INTO EARLY THIS EVENING. A COLD FRONT IS
DROPPING SEWD INTO THE MIDDLE MISSISSIPPI VALLEY WHICH SHOULD BE
THE FOCUS FOR THE CONVECTIVE ACTIVITY. LATEST SFC ANALYSIS SHOWS A
FAIRLY DIFFUSE BOUNDARY WITH LITTLE WIND SHIFT OR TEMPERATURE
CONTRAST INVOF THE BOUNDARY WITH WINDS ONLY GRADUALLY VEERING FROM
WLY TO NWLY. EARLY MORNING STRATUS AND FOG HAS FINALLY CLEARED AND
INCREASED INSOLATION IS ALLOWING SFC TEMPS TO INCREASE INTO THE
80S WITH DEWPOINTS IN THE UPPER 60S TO LOWER 70S. LATEST VISIBLY
SATELLITE IMAGERY IS ALSO INDICATING ENHANCED CU DEVELOPMENT INVOF
THE FRONTAL BOUNDARY. STILL EXPECTING SCT SHOWERS AND
THUNDERSTORMS AS THE FRONT MOVES THROUGH THE AREA...BUT SINCE
CONVECTIVE ACTIVITY IS EXPECTED TO REMAIN SCATTERED...CONFIDENCE
IN EXACT TIMING AND DURATION IS LOW.

FOLLOWING THE FROPA...COOLER...DRIER AIR WILL GRADUALLY FILTER
INTO THE REGION WITH THE STRONGEST COLD ADVECTION DEVELOPING
DURING THE EARLY MORNING HOURS. EXPECT THAT WINDS SHOULD VEER TO
NORTHERLY AND GUST TO ARND 18KT IN TIME FOR THE MORNING RUSH
HOURS. WINDS SHOULD GRADUALLY TAPER OFF THROUGH THE AFTERNOON
TOMORROW AS HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI
VALLEY AND INTO THE WESTERN GREAT LAKES.

KREIN

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEED.

* LOW/MEDIUM CONFIDENCE IN TIMING AND COVERAGE OF SHRA/TSRA.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...VFR. NORTH/NORTHEAST WINDS.

TUESDAY THROUGH WEDNESDAY...VFR. AFTERNOON LAKE BREEZE.

THURSDAY THROUGH SATURDAY...VFR.

BEACHLER

&&

.MARINE...
358 AM CDT

WEAK AREA OF HIGH PRESSURE HAS ARRIVED OVER THE GREAT
LAKES...HOWEVER THIS FEATURE CONTINUES TO PUSH EAST TOWARDS
EASTERN CANADA. THE GRADIENT WILL REMAIN VERY MINIMAL OVER LAKE
MICHIGAN THIS MORNING AND ALLOW FOR WINDS TO BE LIGHT. MEANWHILE A
STRONGER AREA OF LOW PRESSURE WILL PUSH EAST ACROSS LAKE SUPERIOR
TODAY...WITH A TRAILING FRONTAL BOUNDARY. THIS BOUNDARY SHOULD
PUSH ACROSS LAKE MICHIGAN FROM NORTH TO SOUTH...BRINGING STRONGER
WINDS AND LIKELY SMALL CRAFT CONDITIONS TO THE NEARSHORE WATERS OF
ILLINOIS AND NORTHWEST INDIANA BY EARLY MONDAY MORNING. THEN WITH
MUCH COOLER AIR ARRIVING BEHIND THE FRONTAL PASSAGE...WAVES WILL
REMAIN ELEVATED ESPECIALLY FOR THE SOUTHERN HALF OF THE LAKE.
WINDS WILL CONTINUE TO DIMINISH AS ANOTHER RIDGE OF HIGH PRESSURE
SLIDES INTO THE REGION MONDAY NIGHT INTO TUESDAY. DESPITE THE
DIMINISHING WINDS...WAVES WILL LIKELY REMAIN A HAZARD FOR SMALL
CRAFT ALONG THE ILLINOIS AND INDIANA NEARSHORE WATERS THROUGH
MIDDAY TUESDAY.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1143 AM CDT SUN SEP 1 2013

.DISCUSSION...
1045 AM CDT

NO BIG CHANGES MADE TO GOING FORECAST OTHER THAN TO SLOW THE WARM UP
TREND IN HOURLY TEMPS THIS MORNING DUE TO CONSIDERABLE CLOUD COVER.
HAVE LEFT FORECAST HIGHS TEMPS LARGELY AS IS BANKING ON THE FACT
THAT THE FAIRLY HIGH SUN ANGLE SHOULD BE ENOUGH TO ERODE STRATUS AND
ALLOW FOR AT LEAST PARTIAL SUNSHINE AND A QUICK REBOUND IN TEMPS
DURING THE AFTERNOON.

CONVECTIVE CHANCES AND SEVERE POTENTIAL ARE A BIT MORE MURKY. FRONT
THAT PASSED SOUTH OF THE AREA EARLIER THIS WEEKEND TOOK SOME OF THE
MOISTURE WITH IT...THOUGH SURFACE OBS DO SHOW A SMALL RIBBON OF
HIGHER DEWPOINTS BEGINNING TO POOL IN ADVANCE OF THE SECOND AND
STRONGER FRONT THAT WILL MOVE THROUGH LATER TODAY. FRONTAL
CONVERGENCE LOOKS TO BE FAIRLY WEAK WITH SFC WINDS ALL VEERED TO THE
WEST ALREADY AHEAD OF THE FRONT WITH LOW LEVEL MASS CONVERGENCE
BASICALLY JUST SPEED CONVERGENCE WITH STRONGER NORTHWEST WINDS
BEHIND THE FRONT. WATER VAPOR IMAGERY DOES SHOW A SHORTWAVE
ASSOCIATED WITH A SPEED MAX MOVING INTO SOUTHERN MN AND JUST NOW
INTO FAR NORTHERN IOWA THIS MORNING. LARGE SCALE ASCENT IN ADVANCE
THIS FEATURE WILL BE KEY IN THE CONVECTIVE POTENTIAL THIS AFTERNOON
GIVEN THE PALTRY LOW LEVEL CONVERGENCE AND STOUT CAPPING INVERSION
NOTED ON THE 1200 UTC KDVN/KILX SOUNDINGS.

BOTH SOUNDINGS DID SHOW A FAIRLY CLASSIC LOAD GUN TYPE SET UP WITH
STEEP LAPSE RATES LOCATED ABOVE A MOIST BOUNDARY LAYER. ASSUMING
THAT WE ARE ABLE TO HEAT UP AS EXPECTED THIS AFTERNOON THEN MLCAPES
WOULD LIKELY CLIMB ABOVE 2000 J/KG WITH FORECAST RAP SOUNDINGS
SUGGESTING THAT THE CAP WILL BE EFFECTIVELY LIFTED THROUGH WITH
MINIMAL INHIBITION. FAIRLY STOUT 6KM WEST-NORTHWEST WINDS OF 30-35KT
HAVE BEEN SAMPLED UPSTREAM AND ARE PROGGED TO BE OVER THE AREA THIS
AFTERNOON. HOWEVER...LIGHT WESTERLY WINDS AT THE SFC WILL RESULT IN
BULK SHEAR VALUES OF ONLY 25-30KT...WHICH GIVEN MODERATE INSTABILITY
WOULD BE ENOUGH TO ALLOW FOR SOME DEGREE OF STORM ORGANIZATION AND
RESULTANT SEVERE THREAT...PRIMARILY IN THE FORM OF DAMAGING WINDS.
OF COURSE THIS IS ALL CONTINGENT ON SUFFICIENT INSTABILITY ACTUALLY
BEING REALIZED AND THEN STORMS FORMING DESPITE THE MEAGER LOW LEVEL
CONVERGENCE. GIVEN ALL THE UNCERTAINTIES HAVE OPTED TO MAINTAIN POPS
IN THE 40-50% RANGE THIS AFTERNOON INTO EARLY THIS EVENING SOUTHEAST
CWA.

WILL NEED TO WATCH FOR POTENTIAL LAKE BREEZE FORMATION RIGHT ALONG
THE SHORE THIS AFTERNOON GIVEN LIGHT SYNOPTIC WINDS. SHOULD LAKE
BREEZE FORM THE ENHANCED CONVERGENCE COULD BE A FOCAL POINT
CONVECTIVE INITIATION GIVEN THE RELATIVE ABSENCE OF LOW LEVEL
CONVERGENCE ELSEWHERE.

FORECAST GRIDS AND DERIVED PRODUCTS HAVE ALREADY BEEN SENT.

IZZI

//PREV DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* WEST TO WEST-NORTHWEST WINDS TO ARND 10KT. FRONT WILL APPROACH
  WITH WINDS TURNING NORTHWEST/NORTH AND STRENGTHENING FOLLOWING
  FRONTAL PASSAGE.

* ISO SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY ARND 19-22Z.

KREIN

//DISCUSSION...UPDATED 12Z...

SHALLOW GROUND FOG HAS DEVELOPED EARLY THIS MORNING FOR MANY
AIRFIELDS IN NORTHERN IL/NORTHWEST IN...WITH SOME THICKER OR
PATCHY DENSE FOG WEST OF KUGN AIRFIELD. EXPECT FOG TO LIFT/ERODE
BY 13-14Z WITH VSBYS RETURNING TO VFR. WINDS WILL SLOWLY INCREASE
FROM THE SOUTHWEST TO WEST ARND 6-8KT...THEN INCREASE SLIGHTLY TO
10KT BY MIDDAY. A FRONTAL BOUNDARY WILL STEADILY APPROACH THE
REGION FROM THE NORTHWEST AND EXPECT SHOWERS AND THUNDERSTORMS TO
DEVELOP ALONG THIS BOUNDARY. GUIDANCE HAS MAINTAINED A CONSISTENT
THEME OF ARRIVAL AROUND 19-20Z ACROSS FAR NORTHWEST IL...ARRIVING
AT RFD ARND 21-23Z. THEN THIS BOUNDARY AND THUNDERSTORMS WILL
SLIDE SOUTHEAST...REACHING ORD/MDW CLOSER TO 22-24Z. HAVE
MAINTAINED THIS IN THE TAF AS A TEMPO GROUP. EXPECT THE BOUNDARY
TO CONTINUE TO PRESS SOUTHEAST AND SHOULD CLEAR THE TAF SITES BY
00-02Z MON WITH CIGS SLOWLY IMPROVING. WINDS BEHIND THE BOUNDARY
WILL STEADILY TURN NORTHWEST/NORTH AND INCREASE...WITH GUSTS
INTO THE MID TEENS DEVELOPING OVERNIGHT.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* MEDIUM/HIGH CONFIDENCE IN WIND DIR/SPEED.

* LOW/MEDIUM CONFIDENCE IN TIMING AND COVERAGE OF SHRA/TSRA.

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...VFR. NORTH/NORTHEAST WINDS.

TUESDAY THROUGH WEDNESDAY...VFR. AFTERNOON LAKE BREEZE.

THURSDAY THROUGH SATURDAY...VFR.

BEACHLER

&&

.MARINE...
358 AM CDT

WEAK AREA OF HIGH PRESSURE HAS ARRIVED OVER THE GREAT
LAKES...HOWEVER THIS FEATURE CONTINUES TO PUSH EAST TOWARDS
EASTERN CANADA. THE GRADIENT WILL REMAIN VERY MINIMAL OVER LAKE
MICHIGAN THIS MORNING AND ALLOW FOR WINDS TO BE LIGHT. MEANWHILE A
STRONGER AREA OF LOW PRESSURE WILL PUSH EAST ACROSS LAKE SUPERIOR
TODAY...WITH A TRAILING FRONTAL BOUNDARY. THIS BOUNDARY SHOULD
PUSH ACROSS LAKE MICHIGAN FROM NORTH TO SOUTH...BRINGING STRONGER
WINDS AND LIKELY SMALL CRAFT CONDITIONS TO THE NEARSHORE WATERS OF
ILLINOIS AND NORTHWEST INDIANA BY EARLY MONDAY MORNING. THEN WITH
MUCH COOLER AIR ARRIVING BEHIND THE FRONTAL PASSAGE...WAVES WILL
REMAIN ELEVATED ESPECIALLY FOR THE SOUTHERN HALF OF THE LAKE.
WINDS WILL CONTINUE TO DIMINISH AS ANOTHER RIDGE OF HIGH PRESSURE
SLIDES INTO THE REGION MONDAY NIGHT INTO TUESDAY. DESPITE THE
DIMINISHING WINDS...WAVES WILL LIKELY REMAIN A HAZARD FOR SMALL
CRAFT ALONG THE ILLINOIS AND INDIANA NEARSHORE WATERS THROUGH
MIDDAY TUESDAY.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1046 AM CDT SUN SEP 1 2013

.DISCUSSION...
1045 AM CDT

NO BIG CHANGES MADE TO GOING FORECAST OTHER THAN TO SLOW THE WARM UP
TREND IN HOURLY TEMPS THIS MORNING DUE TO CONSIDERABLE CLOUD COVER.
HAVE LEFT FORECAST HIGHS TEMPS LARGELY AS IS BANKING ON THE FACT
THAT THE FAIRLY HIGH SUN ANGLE SHOULD BE ENOUGH TO ERODE STRATUS AND
ALLOW FOR AT LEAST PARTIAL SUNSHINE AND A QUICK REBOUND IN TEMPS
DURING THE AFTERNOON.

CONVECTIVE CHANCES AND SEVERE POTENTIAL ARE A BIT MORE MURKY. FRONT
THAT PASSED SOUTH OF THE AREA EARLIER THIS WEEKEND TOOK SOME OF THE
MOISTURE WITH IT...THOUGH SURFACE OBS DO SHOW A SMALL RIBBON OF
HIGHER DEWPOINTS BEGINNING TO POOL IN ADVANCE OF THE SECOND AND
STRONGER FRONT THAT WILL MOVE THROUGH LATER TODAY. FRONTAL
CONVERGENCE LOOKS TO BE FAIRLY WEAK WITH SFC WINDS ALL VEERED TO THE
WEST ALREADY AHEAD OF THE FRONT WITH LOW LEVEL MASS CONVERGENCE
BASICALLY JUST SPEED CONVERGENCE WITH STRONGER NORTHWEST WINDS
BEHIND THE FRONT. WATER VAPOR IMAGERY DOES SHOW A SHORTWAVE
ASSOCIATED WITH A SPEED MAX MOVING INTO SOUTHERN MN AND JUST NOW
INTO FAR NORTHERN IOWA THIS MORNING. LARGE SCALE ASCENT IN ADVANCE
THIS FEATURE WILL BE KEY IN THE CONVECTIVE POTENTIAL THIS AFTERNOON
GIVEN THE PALTRY LOW LEVEL CONVERGENCE AND STOUT CAPPING INVERSION
NOTED ON THE 1200 UTC KDVN/KILX SOUNDINGS.

BOTH SOUNDINGS DID SHOW A FAIRLY CLASSIC LOAD GUN TYPE SET UP WITH
STEEP LAPSE RATES LOCATED ABOVE A MOIST BOUNDARY LAYER. ASSUMING
THAT WE ARE ABLE TO HEAT UP AS EXPECTED THIS AFTERNOON THEN MLCAPES
WOULD LIKELY CLIMB ABOVE 2000 J/KG WITH FORECAST RAP SOUNDINGS
SUGGESTING THAT THE CAP WILL BE EFFECTIVELY LIFTED THROUGH WITH
MINIMAL INHIBITION. FAIRLY STOUT 6KM WEST-NORTHWEST WINDS OF 30-35KT
HAVE BEEN SAMPLED UPSTREAM AND ARE PROGGED TO BE OVER THE AREA THIS
AFTERNOON. HOWEVER...LIGHT WESTERLY WINDS AT THE SFC WILL RESULT IN
BULK SHEAR VALUES OF ONLY 25-30KT...WHICH GIVEN MODERATE INSTABILITY
WOULD BE ENOUGH TO ALLOW FOR SOME DEGREE OF STORM ORGANIZATION AND
RESULTANT SEVERE THREAT...PRIMARILY IN THE FORM OF DAMAGING WINDS.
OF COURSE THIS IS ALL CONTINGENT ON SUFFICIENT INSTABILITY ACTUALLY
BEING REALIZED AND THEN STORMS FORMING DESPITE THE MEAGER LOW LEVEL
CONVERGENCE. GIVEN ALL THE UNCERTAINTIES HAVE OPTED TO MAINTAIN POPS
IN THE 40-50% RANGE THIS AFTERNOON INTO EARLY THIS EVENING SOUTHEAST
CWA.

WILL NEED TO WATCH FOR POTENTIAL LAKE BREEZE FORMATION RIGHT ALONG
THE SHORE THIS AFTERNOON GIVEN LIGHT SYNOPTIC WINDS. SHOULD LAKE
BREEZE FORM THE ENHANCED CONVERGENCE COULD BE A FOCAL POINT
CONVECTIVE INITIATION GIVEN THE RELATIVE ABSENCE OF LOW LEVEL
CONVERGENCE ELSEWHERE.

FORECAST GRIDS AND DERIVED PRODUCTS HAVE ALREADY BEEN SENT.

IZZI

&&

.PREV DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* SOUTHWEST/WEST WINDS WILL INCREASE TO ARND 10KT LATE MORNING.
  FRONT WILL APPROACH WITH WINDS TURNING NORTHWEST/NORTH AFT
  00Z.

* ISO SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY ARND 22-24Z.

KREIN

//DISCUSSION...UPDATED 12Z...

SHALLOW GROUND FOG HAS DEVELOPED EARLY THIS MORNING FOR MANY
AIRFIELDS IN NORTHERN IL/NORTHWEST IN...WITH SOME THICKER OR
PATCHY DENSE FOG WEST OF KUGN AIRFIELD. EXPECT FOG TO LIFT/ERODE
BY 13-14Z WITH VSBYS RETURNING TO VFR. WINDS WILL SLOWLY INCREASE
FROM THE SOUTHWEST TO WEST ARND 6-8KT...THEN INCREASE SLIGHTLY TO
10KT BY MIDDAY. A FRONTAL BOUNDARY WILL STEADILY APPROACH THE
REGION FROM THE NORTHWEST AND EXPECT SHOWERS AND THUNDERSTORMS TO
DEVELOP ALONG THIS BOUNDARY. GUIDANCE HAS MAINTAINED A CONSISTENT
THEME OF ARRIVAL AROUND 19-20Z ACROSS FAR NORTHWEST IL...ARRIVING
AT RFD ARND 21-23Z. THEN THIS BOUNDARY AND THUNDERSTORMS WILL
SLIDE SOUTHEAST...REACHING ORD/MDW CLOSER TO 22-24Z. HAVE
MAINTAINED THIS IN THE TAF AS A TEMPO GROUP. EXPECT THE BOUNDARY
TO CONTINUE TO PRESS SOUTHEAST AND SHOULD CLEAR THE TAF SITES BY
00-02Z MON WITH CIGS SLOWLY IMPROVING. WINDS BEHIND THE BOUNDARY
WILL STEADILY TURN NORTHWEST/NORTH AND INCREASE...WITH GUSTS
INTO THE MID TEENS DEVELOPING OVERNIGHT.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN WIND DIR/SPEED.

* MEDIUM/HIGH CONFIDENCE IN SHRA/TSRA DEVELOPING AFT 20Z.

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...VFR. NORTH/NORTHEAST WINDS.

TUESDAY THROUGH WEDNESDAY...VFR. AFTERNOON LAKE BREEZE.

THURSDAY THROUGH SATURDAY...VFR.

BEACHLER

&&

.MARINE...
358 AM CDT

WEAK AREA OF HIGH PRESSURE HAS ARRIVED OVER THE GREAT
LAKES...HOWEVER THIS FEATURE CONTINUES TO PUSH EAST TOWARDS
EASTERN CANADA. THE GRADIENT WILL REMAIN VERY MINIMAL OVER LAKE
MICHIGAN THIS MORNING AND ALLOW FOR WINDS TO BE LIGHT. MEANWHILE A
STRONGER AREA OF LOW PRESSURE WILL PUSH EAST ACROSS LAKE SUPERIOR
TODAY...WITH A TRAILING FRONTAL BOUNDARY. THIS BOUNDARY SHOULD
PUSH ACROSS LAKE MICHIGAN FROM NORTH TO SOUTH...BRINGING STRONGER
WINDS AND LIKELY SMALL CRAFT CONDITIONS TO THE NEARSHORE WATERS OF
ILLINOIS AND NORTHWEST INDIANA BY EARLY MONDAY MORNING. THEN WITH
MUCH COOLER AIR ARRIVING BEHIND THE FRONTAL PASSAGE...WAVES WILL
REMAIN ELEVATED ESPECIALLY FOR THE SOUTHERN HALF OF THE LAKE.
WINDS WILL CONTINUE TO DIMINISH AS ANOTHER RIDGE OF HIGH PRESSURE
SLIDES INTO THE REGION MONDAY NIGHT INTO TUESDAY. DESPITE THE
DIMINISHING WINDS...WAVES WILL LIKELY REMAIN A HAZARD FOR SMALL
CRAFT ALONG THE ILLINOIS AND INDIANA NEARSHORE WATERS THROUGH
MIDDAY TUESDAY.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 901 AM CDT SUN SEP 1 2013

.DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* SOUTHWEST/WEST WINDS WILL INCREASE TO ARND 10KT LATE MORNING.
  FRONT WILL APPROACH WITH WINDS TURNING NORTHWEST/NORTH AFT
  00Z.

* ISO SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY ARND 22-24Z.

KREIN

//DISCUSSION...UPDATED 12Z...

SHALLOW GROUND FOG HAS DEVELOPED EARLY THIS MORNING FOR MANY
AIRFIELDS IN NORTHERN IL/NORTHWEST IN...WITH SOME THICKER OR
PATCHY DENSE FOG WEST OF KUGN AIRFIELD. EXPECT FOG TO LIFT/ERODE
BY 13-14Z WITH VSBYS RETURNING TO VFR. WINDS WILL SLOWLY INCREASE
FROM THE SOUTHWEST TO WEST ARND 6-8KT...THEN INCREASE SLIGHTLY TO
10KT BY MIDDAY. A FRONTAL BOUNDARY WILL STEADILY APPROACH THE
REGION FROM THE NORTHWEST AND EXPECT SHOWERS AND THUNDERSTORMS TO
DEVELOP ALONG THIS BOUNDARY. GUIDANCE HAS MAINTAINED A CONSISTENT
THEME OF ARRIVAL AROUND 19-20Z ACROSS FAR NORTHWEST IL...ARRIVING
AT RFD ARND 21-23Z. THEN THIS BOUNDARY AND THUNDERSTORMS WILL
SLIDE SOUTHEAST...REACHING ORD/MDW CLOSER TO 22-24Z. HAVE
MAINTAINED THIS IN THE TAF AS A TEMPO GROUP. EXPECT THE BOUNDARY
TO CONTINUE TO PRESS SOUTHEAST AND SHOULD CLEAR THE TAF SITES BY
00-02Z MON WITH CIGS SLOWLY IMPROVING. WINDS BEHIND THE BOUNDARY
WILL STEADILY TURN NORTHWEST/NORTH AND INCREASE...WITH GUSTS
INTO THE MID TEENS DEVELOPING OVERNIGHT.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN WIND DIR/SPEED.

* MEDIUM/HIGH CONFIDENCE IN SHRA/TSRA DEVELOPING AFT 20Z.

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...VFR. NORTH/NORTHEAST WINDS.

TUESDAY THROUGH WEDNESDAY...VFR. AFTERNOON LAKE BREEZE.

THURSDAY THROUGH SATURDAY...VFR.

BEACHLER

&&

.MARINE...
358 AM CDT

WEAK AREA OF HIGH PRESSURE HAS ARRIVED OVER THE GREAT
LAKES...HOWEVER THIS FEATURE CONTINUES TO PUSH EAST TOWARDS
EASTERN CANADA. THE GRADIENT WILL REMAIN VERY MINIMAL OVER LAKE
MICHIGAN THIS MORNING AND ALLOW FOR WINDS TO BE LIGHT. MEANWHILE A
STRONGER AREA OF LOW PRESSURE WILL PUSH EAST ACROSS LAKE SUPERIOR
TODAY...WITH A TRAILING FRONTAL BOUNDARY. THIS BOUNDARY SHOULD
PUSH ACROSS LAKE MICHIGAN FROM NORTH TO SOUTH...BRINGING STRONGER
WINDS AND LIKELY SMALL CRAFT CONDITIONS TO THE NEARSHORE WATERS OF
ILLINOIS AND NORTHWEST INDIANA BY EARLY MONDAY MORNING. THEN WITH
MUCH COOLER AIR ARRIVING BEHIND THE FRONTAL PASSAGE...WAVES WILL
REMAIN ELEVATED ESPECIALLY FOR THE SOUTHERN HALF OF THE LAKE.
WINDS WILL CONTINUE TO DIMINISH AS ANOTHER RIDGE OF HIGH PRESSURE
SLIDES INTO THE REGION MONDAY NIGHT INTO TUESDAY. DESPITE THE
DIMINISHING WINDS...WAVES WILL LIKELY REMAIN A HAZARD FOR SMALL
CRAFT ALONG THE ILLINOIS AND INDIANA NEARSHORE WATERS THROUGH
MIDDAY TUESDAY.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
     ILZ012-ILZ013-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-
     ILZ033-ILZ039 UNTIL 10 AM SUNDAY.

     BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

     DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 10
     AM SUNDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 649 AM CDT SUN SEP 1 2013

.DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* PATCHY GROUND FOG DEVELOPED EARLY THIS MORNING...CURRENTLY IS
  HOLDING WEST OF ORD/MDW WHERE VSBYS HAVE REDUCED TO LESS THAN
  1/2SM IN SPOTS.

* SOUTHWEST/WEST WINDS WILL INCREASE TO ARND 6-8KT AFT 13Z...THEN
  FRONT WILL APPROACH WITH WINDS TURNING NORTHWEST/NORTH AFT 00Z.

* ISO SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY ARND 22-24Z.

BEACHLER

//DISCUSSION...UPDATED 12Z...

SHALLOW GROUND FOG HAS DEVELOPED EARLY THIS MORNING FOR MANY
AIRFIELDS IN NORTHERN IL/NORTHWEST IN...WITH SOME THICKER OR
PATCHY DENSE FOG WEST OF KUGN AIRFIELD. EXPECT FOG TO LIFT/ERODE
BY 13-14Z WITH VSBYS RETURNING TO VFR. WINDS WILL SLOWLY INCREASE
FROM THE SOUTHWEST TO WEST ARND 6-8KT...THEN INCREASE SLIGHTLY TO
10KT BY MIDDAY. A FRONTAL BOUNDARY WILL STEADILY APPROACH THE
REGION FROM THE NORTHWEST AND EXPECT SHOWERS AND THUNDERSTORMS TO
DEVELOP ALONG THIS BOUNDARY. GUIDANCE HAS MAINTAINED A CONSISTENT
THEME OF ARRIVAL AROUND 19-20Z ACROSS FAR NORTHWEST IL...ARRIVING
AT RFD ARND 21-23Z. THEN THIS BOUNDARY AND THUNDERSTORMS WILL
SLIDE SOUTHEAST...REACHING ORD/MDW CLOSER TO 22-24Z. HAVE
MAINTAINED THIS IN THE TAF AS A TEMPO GROUP. EXPECT THE BOUNDARY
TO CONTINUE TO PRESS SOUTHEAST AND SHOULD CLEAR THE TAF SITES BY
00-02Z MON WITH CIGS SLOWLY IMPROVING. WINDS BEHIND THE BOUNDARY
WILL STEADILY TURN NORTHWEST/NORTH AND INCREASE...WITH GUSTS
INTO THE MID TEENS DEVELOPING OVERNIGHT.

BEACHLER


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* MEDIUM/HIGH CONFIDENCE IN PATCHY FOG DISSIPATING AROUND 13-14Z.

* HIGH CONFIDENCE IN WIND DIR/SPEED.

* MEDIUM/HIGH CONFIDENCE IN SHRA/TSRA DEVELOPING AFT 20Z.


BEACHLER

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT...VFR. NORTH/NORTHEAST WINDS.

TUESDAY THROUGH WEDNESDAY...VFR. AFTERNOON LAKE BREEZE.

THURSDAY THROUGH SATURDAY...VFR.

BEACHLER

&&

.MARINE...
358 AM CDT

WEAK AREA OF HIGH PRESSURE HAS ARRIVED OVER THE GREAT
LAKES...HOWEVER THIS FEATURE CONTINUES TO PUSH EAST TOWARDS
EASTERN CANADA. THE GRADIENT WILL REMAIN VERY MINIMAL OVER LAKE
MICHIGAN THIS MORNING AND ALLOW FOR WINDS TO BE LIGHT. MEANWHILE A
STRONGER AREA OF LOW PRESSURE WILL PUSH EAST ACROSS LAKE SUPERIOR
TODAY...WITH A TRAILING FRONTAL BOUNDARY. THIS BOUNDARY SHOULD
PUSH ACROSS LAKE MICHIGAN FROM NORTH TO SOUTH...BRINGING STRONGER
WINDS AND LIKELY SMALL CRAFT CONDITIONS TO THE NEARSHORE WATERS OF
ILLINOIS AND NORTHWEST INDIANA BY EARLY MONDAY MORNING. THEN WITH
MUCH COOLER AIR ARRIVING BEHIND THE FRONTAL PASSAGE...WAVES WILL
REMAIN ELEVATED ESPECIALLY FOR THE SOUTHERN HALF OF THE LAKE.
WINDS WILL CONTINUE TO DIMINISH AS ANOTHER RIDGE OF HIGH PRESSURE
SLIDES INTO THE REGION MONDAY NIGHT INTO TUESDAY. DESPITE THE
DIMINISHING WINDS...WAVES WILL LIKELY REMAIN A HAZARD FOR SMALL
CRAFT ALONG THE ILLINOIS AND INDIANA NEARSHORE WATERS THROUGH
MIDDAY TUESDAY.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
     ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
     ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 AM SUNDAY.

     BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

     DENSE FOG ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 9
     AM SUNDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 359 AM CDT SUN SEP 1 2013

.DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* PATCHY GROUND FOG CONTINUES TO DEVELOP WITH VSBY REDUCTIONS
  EXPECTED THROUGH DAYBREAK.


* ISO SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY AFT 21Z.

BEACHLER

//DISCUSSION...UPDATED 06Z...

VERY MOIST AND CALM AIRMASS OVERHEAD...WITH THINNING STRATUS CLOUD
COVER. THIS ALL POINTS TOWARDS PATCHY FOG DEVELOPING AND REDUCING
VSBYS TO MVFR AND A FEW AREAS OF IFR. WITH THE LACK OF A GRADIENT
OVERNIGHT...WINDS WILL BECOME NEARLY CALM IN A FEW LOCATIONS. THIS
SHOULD AID IN FOG FORMATION ALONG WITH RECENT RAINFALL.

THEN AFT DAYBREAK HEATING SHOULD PROVIDE SOME
INSTABILITY...HOWEVER NOT EXPECTING ANY SHRA/TSRA TO DEVELOP UNTIL
THE FRONTAL BOUNDARY APPROACHES THE REGION FROM THE NORTHWEST. AT
THIS TIME CURRENT GUIDANCE WOULD SUGGEST LIGHT WINDS FROM THE
SOUTHWEST THRU MUCH OF THE DAY...THEN AS THE BOUNDARY NEARS AROUND
20-22Z SHRA/TSRA WILL BEGIN TO DEVELOP. THEN THE BOUNDARY PASSAGE
IS POISED FOR 00-02Z AND WILL ALLOW WINDS TO VEER TO
NORTHWEST/NORTH.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND DIR/SPEED.

* MEDIUM/HIGH CONFIDENCE IN PATCHY FOG DEVELOPING.

* MEDIUM CONFIDENCE IN ORD/MDW REMAINING MVFR VSBYS FROM FOG.

* MEDIUM/HIGH CONFIDENCE IN SHRA/TSRA DEVELOPING AFT 20Z.

BEACHLER

//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...

MONDAY...VFR. NORTH-NORTHEAST WINDS.

TUESDAY...VFR. LAKE BREEZE LIKELY.

WEDNESDAY...VFR.

THURSDAY...VFR. NORTHEAST WINDS.

FRIDAY...VFR.

RC

&&

.MARINE...
358 AM CDT

WEAK AREA OF HIGH PRESSURE HAS ARRIVED OVER THE GREAT
LAKES...HOWEVER THIS FEATURE CONTINUES TO PUSH EAST TOWARDS
EASTERN CANADA. THE GRADIENT WILL REMAIN VERY MINIMAL OVER LAKE
MICHIGAN THIS MORNING AND ALLOW FOR WINDS TO BE LIGHT. MEANWHILE A
STRONGER AREA OF LOW PRESSURE WILL PUSH EAST ACROSS LAKE SUPERIOR
TODAY...WITH A TRAILING FRONTAL BOUNDARY. THIS BOUNDARY SHOULD
PUSH ACROSS LAKE MICHIGAN FROM NORTH TO SOUTH...BRINGING STRONGER
WINDS AND LIKELY SMALL CRAFT CONDITIONS TO THE NEARSHORE WATERS OF
ILLINOIS AND NORTHWEST INDIANA BY EARLY MONDAY MORNING. THEN WITH
MUCH COOLER AIR ARRIVING BEHIND THE FRONTAL PASSAGE...WAVES WILL
REMAIN ELEVATED ESPECIALLY FOR THE SOUTHERN HALF OF THE LAKE.
WINDS WILL CONTINUE TO DIMINISH AS ANOTHER RIDGE OF HIGH PRESSURE
SLIDES INTO THE REGION MONDAY NIGHT INTO TUESDAY. DESPITE THE
DIMINISHING WINDS...WAVES WILL LIKELY REMAIN A HAZARD FOR SMALL
CRAFT ALONG THE ILLINOIS AND INDIANA NEARSHORE WATERS THROUGH
MIDDAY TUESDAY.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 353 AM CDT SUN SEP 1 2013

.DISCUSSION...
352 AM CDT

MAIN CONCERNS THIS FORECAST PERIOD ARE WITH FOG EARLY THIS MORNING
ACROSS THE ENTIRE AREA...THUNDERSTORMS SOME OF WHICH COULD BE
STRONG AND MAYBE EVEN AN ISOLATED SEVERE THREAT...AS WELL AS MUCH
COOLER TEMPS WITH BEACH HAZARDS EXPECTED MONDAY.

CONTINUE TO MONITOR FOG POTENTIAL EARLY THIS MORNING WITH SEVERAL
SITES CURRENTLY REPORTING VIS BELOW ONE MILE...WITH SOME ISOLATED
LOCATIONS BOUNCING AROUND ONE QUARTER MILE AT TIMES. ALTHOUGH FOG
IS CURRENTLY BEING OBSERVED ACROSS THE ENTIRE CWA...MAIN CONCERN
RIGHT NOW IS THE FAR NORTHWEST AND FAR NORTHERN CWA. LOWEST VIS IS
IN THIS LOCATION AT THIS TIME...WITH LATEST SATELLITE IMAGERY
DEPICTING THE POTENTIAL FOR THE MORE DENSE FOG WHICH HAS BEEN
RESIDING JUST OUTSIDE OF THE CWA BEGINNING TO SPREAD INTO THE CWA.
HAD ISSUED AN SPS EARLIER FOR THIS FOG/LOW VIS...BUT WILL MAKE A
LAST MINUTE DECISION HERE IN THE NEAR TERM WITH THE POTENTIAL FOR
A FOG ADVISORY. ALTHOUGH...DO EXPECT ANY FOG THIS MORNING TO
QUICKLY DISSIPATE WITH THE APPROACH OF SUNRISE. LOW LEVEL STRATUS
ALSO REMAINS ACROSS PORTIONS OF THE CWA...IN PARTICULAR THE
SOUTHEAST CWA. IT HAS SHOWN A DISSIPATING TREND AS IT SLOWLY MOVES
EAST THIS MORNING...AND EXPECT THIS TREND TO CONTINUE THIS
MORNING. ALTHOUGH AS THIS STRATUS DEPARTS TO THE EAST...MID/HIGH
LEVEL CLOUD COVER SHOULD CONTINUE TO SPREAD EASTWARD ACROSS THE
CWA THROUGH MID MORNING. MOST LOCATIONS SHOULD OBSERVE A PERIOD OF
SUNSHINE THIS MORNING...BUT WITH THE ARRIVAL OF THIS MID/HIGH
LEVEL CLOUD COVER MOST LOCATIONS SHOULD GO MORE PARTLY CLOUDY TO
PARTLY SUNNY. DESPITE A FAIRLY WARM AIR MASS STILL IN PLACE...DID
SLIGHTLY LOWER HIGH TEMPS TODAY. NONETHELESS...MID TO UPPER 80S
WILL STILL BE REACHABLE WITH SOME AREAS ACROSS THE SOUTHERN CWA
POSSIBLY APPROACHING THE 90 DEGREE MARK. IF YOU STEP OUTSIDE THIS
MORNING...YOU WILL NOTICE THAT MUGGY CONDITIONS ARE IN STILL IN
PLACE. THIS IS A RESULT OF MID TO UPPER 60 DEGREE DEWPOINTS...THAT
SHOULD ACTUALLY SLIGHTLY INCREASE AND APPROACH 70 DEGREES. THIS
WILL RESULT IN SOME LOCATIONS...MAINLY THE SOUTHWEST CWA OBSERVING
MID 90 DEGREE HEAT INDICES WITH UPPER 90 DEGREE HEAT INDICES NOT
OUT OF THE QUESTION IN THOSE LOCATIONS.

PRECIP TRENDS LATER THIS MORNING AND ESPECIALLY INTO THE AFTERNOON
REMAIN SOMEWHAT UNCERTAIN AT THIS TIME...WITH GUIDANCE VARYING AS
TO THE EXTENT OF THE COVERAGE OF THUNDERSTORMS. MADE ONLY MINOR
ADJUSTED TO POPS FOR TODAY...MAINLY ADJUSTING THE TIMING AND
TRENDS INTO THE AFTERNOON. AS LARGE SCALE VORT MAX ACROSS THE
UPPER MIDWEST SHIFTS TO THE EAST TODAY...SOUTHERN EDGE OF THIS
WAVE AS WELL AS SMALLER SCALE IMPULSES SHOULD DROP SOUTHEAST
TOWARDS THE AREA LATER THIS MORNING AND AFTERNOON. THIS WILL HELP
AN ATTENDANT SURFACE TROUGH AND ASSOCIATED COLD FRONT DROP
SOUTHEAST TOWARDS THE CWA BY MID DAY. DESPITE THIS FRONT AND SOME
SUPPORT ALOFT APPROACHING...THERE WILL BE SOME LIMITING FACTORS IN
PLACE THAT COULD LIMIT THE OVERALL COVERAGE OF THUNDERSTORM
DEVELOPMENT TODAY. FIRST...LOW-MID LEVEL FLOW ARE FORECAST TO
ALREADY BE WEST IF NOT NORTHWEST OUT AHEAD OF THIS FRONT...WITH
LATEST RAP ANALYSIS ALREADY SHOWING THIS TREND. THIS WILL LIMIT
THE COVERAGE AND STRENGTH OF ANY LOW/MID LEVEL CONVERGENCE.
SECOND...CLOUD COVER SPREADING SOUTHEAST ACROSS THE CWA COULD PLAY
INTO THE AMOUNT OF HEATING/DESTABILIZATION. WITHOUT ANY CLOUD
COVER...MLCAPE VALUES COULD REACH OR EXCEED 2000 J/KG ONCE AGAIN
TODAY. WITH THIS AMOUNT OF INSTABILITY AND WITH THE PRESENCE OF
SUFFICIENT MOISTURE AND A BOUNDARY...I AM A LITTLE CONCERNED FOR
THUNDERSTORM POTENTIAL TODAY. ALTHOUGH ONCE AGAIN...THIS CLOUD
COVER COULD LIMIT THE AMOUNT OF INSTABILITY. DESPITE THESE
LIMITING FACTORS...DO FEEL THAT HIGH CHANCE POPS MAKING MENTION OF
SCATTERED THUNDERSTORMS IS WARRANTED FOR MOST LOCATIONS TODAY INTO
THE EARLY EVENING. ALTHOUGH ITS CONCEIVABLE MOST LOCATIONS WILL
NOT OBSERVE PRECIP TODAY...ISOLATED TO SCATTERED DEVELOPMENT IS AT
LEAST A POSSIBILITY. IF THIS CLOUD COVER CAN EXIT AND
HEATING/SUFFICIENT DESTABILIZATION OCCURS...STRONG THUNDERSTORMS
WITH EVEN AN ISOLATED SEVERE STORM WILL BE POSSIBLE DESPITE THE
LACK OF BULK SHEAR...AND THIS WILL OCCUR WHERE EVER BEST
CONVERGENCE CAN OCCUR.

COOLER TEMPS FILTERING IN ON THE BACKSIDE OF THIS SYSTEM WILL
PROVIDE MUCH COOLER TEMPS ON MONDAY...WITH FORECAST HIGHS IN THE
70S EXPECTED. DID ADD CLOUD COVER FOR MONDAY AS I DO THINK
STRATOCU DEVELOPMENT WILL OCCUR...WITH CYCLONIC FLOW STILL IN
PLACE. ALSO...ITS POSSIBLE THAT WITH THIS COOLER AIR MOVING DOWN
THE LAKE...CLOUD COVER COULD SPILL INTO AREAS IMMEDIATE TO THE
LAKE MONDAY NIGHT. STRONGER NORTHERLY WINDS RESULTING IN HIGHER
WAVES...WILL MAKE FOR DANGEROUS SWIMMING CONDITIONS LATE TONIGHT
INTO MONDAY AND TUESDAY WITH A BEACH HAZARDS STATEMENT ISSUED AT
THIS TIME.

RODRIGUEZ

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* PATCHY MVFR CIGS SLOWLY DISSIPATING...WITH PSBL GROUND FOG
  DEVELOPING AFT 08Z.

* PATCHY FOG MAY REDUCE VSBYS TO MVFR TO IFR THRU DAYBREAK.

* ISO SHRA/TSRA DEVELOPING ALONG FRONTAL BOUNDARY AFT 21Z.

BEACHLER

//DISCUSSION...UPDATED 06Z...

VERY MOIST AND CALM AIRMASS OVERHEAD...WITH THINNING STRATUS CLOUD
COVER. THIS ALL POINTS TOWARDS PATCHY FOG DEVELOPING AND REDUCING
VSBYS TO MVFR AND A FEW AREAS OF IFR. WITH THE LACK OF A GRADIENT
OVERNIGHT...WINDS WILL BECOME NEARLY CALM IN A FEW LOCATIONS. THIS
SHOULD AID IN FOG FORMATION ALONG WITH RECENT RAINFALL.

THEN AFT DAYBREAK HEATING SHOULD PROVIDE SOME
INSTABILITY...HOWEVER NOT EXPECTING ANY SHRA/TSRA TO DEVELOP UNTIL
THE FRONTAL BOUNDARY APPROACHES THE REGION FROM THE NORTHWEST. AT
THIS TIME CURRENT GUIDANCE WOULD SUGGEST LIGHT WINDS FROM THE
SOUTHWEST THRU MUCH OF THE DAY...THEN AS THE BOUNDARY NEARS AROUND
20-22Z SHRA/TSRA WILL BEGIN TO DEVELOP. THEN THE BOUNDARY PASSAGE
IS POISED FOR 00-02Z AND WILL ALLOW WINDS TO VEER TO
NORTHWEST/NORTH.

BEACHLER

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN WIND DIR/SPEED.

* MEDIUM/HIGH CONFIDENCE IN PATCHY FOG DEVELOPING.

* MEDIUM CONFIDENCE IN ORD/MDW REMAINING MVFR VSBYS FROM FOG.

* MEDIUM/HIGH CONFIDENCE IN SHRA/TSRA DEVELOPING AFT 20Z.

BEACHLER

//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...

MONDAY...VFR. NORTH-NORTHEAST WINDS.

TUESDAY...VFR. LAKE BREEZE LIKELY.

WEDNESDAY...VFR.

THURSDAY...VFR. NORTHEAST WINDS.

FRIDAY...VFR.

RC

&&

.MARINE...

335 PM...A WEAK RIDGE OF HIGH PRESSURE OVER THE NORTHERN LAKES
WILL MOVE EAST TONIGHT AS LOW PRESSURE MOVES ACROSS ONTARIO AND
LAKE SUPERIOR ON SUNDAY. A TRAILING COLD FRONT WILL MOVE ACROSS
LAKE MICHIGAN LATE SUNDAY AFTERNOON INTO SUNDAY EVENING. THE
GRADIENT WILL TIGHTEN BEHIND THIS FRONT AND COMBINED WITH MUCH
COOLER AIR SPREADING ACROSS REGION...NORTHERLY WINDS WILL INCREASE
TO 20 TO 25 KTS WITH SOME HIGHER GUSTS POSSIBLE. THESE WINDS WILL
SLOWLY DIMINISH MONDAY NIGHT INTO TUESDAY AS HIGH PRESSURE BUILDS
ACROSS THE NORTHERN PLAINS MONDAY NIGHT AND ACROSS THE LAKES
REGION TUESDAY AND TUESDAY NIGHT. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...4 AM MONDAY TO 7 PM
     TUESDAY.

IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...4 AM MONDAY TO 7 PM
     TUESDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...4 AM MONDAY TO 4 PM TUESDAY.

&&

$$

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AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 403 AM CDT SUN SEP 1 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 252 AM CDT SUN SEP 1 2013

TODAY...HAVE HANDLED OVERNIGHT FOG DEVELOPMENT WITH A SPECIAL WX
STATEMENT AND HOPE ARRIVING FRONTAL PROCESSES AND HIGH CLOUD COVER
WILL LIMIT ADDITIONAL DEVELOPMENT TO PREVENT A NEED FOR AN ADVISORY.
CURRENT EXTRAPOLATION OF UPSTREAM INCOMING FRONT GENERALLY AGREES
WITH SREF PLACEMENT OF THIS FEATURE CROSSING THE MS RVR AT AROUND
17-18Z OR SO TODAY. MORE IMPORTANTLY WHEN LOOKING AT UPSTREAM
CONVECTIVE TRENDS AND PRESSURE FALLS...IT APPEARS THAT SOME OF THE
MCS WEST OF THE DSM AREA WILL CONTINUE TO PROPAGATE TOWARD/ ALONG
BETTER INSTABILITY AND LLVL MOISTURE GRADIENTS AND MAKE IT ACRS AT
LEAST THE SOUTHWESTERN THIRD OF THE DVN CWA THIS MORNING. NORTHEAST
OF THAT AN ACRS THE REST OF THE DVN CWA...MAY JUST HAVE DECAYING
DEBRIS OR DWINDLING AREAS OF STRATI-FORMING OUT PRECIP. SEVERAL OF
THE HIGH-RES MODELS DRY THE INCOMING PRECIP UP ENOUGH THE BULK OF THE
CWA WILL REMAIN DRY THROUGH 18Z. BUT WITH THE INCOMING FRONT...DEEPER
FORCING UNDER DIFFLUENT NORTHWESTERLIES AND EMBEDDED WAVE ALOFT...
WILL KEEP CHC POPS GOING THROUGH 18Z EXCEPT FOR THE FAR SOUTHWEST
WHERE WILL GO WITH HIGH CHC TO LIKELY POPS FOR NOW AND MAY HAVE TO
UPDATE LATER TO CATEGORICAL. MAY ALSO HAVE TO EXPAND HIGHER POPS
FURTHER TO THE NORTH AND EAST. THUS SOME HOPE FOR RAIN FOR
LOCALIZED DROUGHT AREAS THIS MORNING. CHALLENGING TEMP FCST AND
AFTERNOON INSTABILITY SCENARIO DEPENDING ON WHAT HAPPENS THIS
MORNING AND LINGERING AFFECTS OF CONVECTIVE DEBRIS. THTA-E
ADVECTION FROM THE SOUTH AND PRE-FRONTAL WARM AIR SURGE WOULD
SUGGEST TEMPS ACRS THE SOUTHERN AND SOUTHEASTERN CWA IN THE UPPER
80S TO AROUND 90 DEGREES WITH DPTS AT LEAST IN THE UPPER 60 TO
AROUND 70. THIS WOULD MAKE FOR INSTABILITY AND CAPES CAPABLE OF
SUPPORTING STRONG TO A FEW SVR STORMS THIS AFTERNOON IN CENTRAL IL
AND POSSIBLY EXTENDING WESTWARD BACK INTO THE SOUTHEASTERN AND
EAST CENTRAL DVN FCST AREA. BUT AGAIN...MUCH UNCERTAINTY WITH
CLOUDS/DEBRIS FORM THE MORNING/UPSTREAM CONVECTIVE ACTIVITY
POSSIBLY HAMPERING THE TRUE HEAT UP ABILITY AND INSTABILITY AND
FCST TEMPS MAY BE WELL TOO WARM ESPECIALLY ACRS THE SOUTH/
SOUTHEAST. WILL STILL KEEP HIGHER AFTERNOON POPS FOR THIS
POTENTIAL ACRS THE SOUTHEASTERN THIRD OF THE FCST AREA THIS
AFTERNOON...BUT IF THIS MORNING/S SHOWER/STORM CHANCES INCREASE
AND CONTINUE TO DEVELOP ACRS THESE AREAS THIS MORNING...THAT MAY
BE IT FOR THE LOCAL AREA AND THE AFTERNOON RE-DEVELOPMENT WILL
OCCUR OFF TO THE EAST OF THE DVN CWA. OTHERWISE POST-FRONTAL
CLEARING PROCESSES THIS AFTERNOON AND EVENING ACRS THE REST OF THE
DVN CWA.

TONIGHT...SEASONABLY STRONG CANADIAN SFC ANTICYCLONE/HIGH STILL ON
TRACK TO DUMP DOWN THE NORTHERN PLAINS AND UPPER MS RVR VALLEY WITH
ASSOCIATED AIRMASS RELIEF FROM THE NORTH. WILL BANK ON INHERENT
NORTHERLY SFC FLOW AND LOWER SFC DPT INFLUX TO PREVENT MORE FOG
DEVELOPMENT TONIGHT DESPITE CLEAR OUT AND SFC TEMP COOL DOWN. LOW
TEMPS IN THE 50S TO LOWER 60S...SOME MID 50S POSSIBLE NORTH OF I80.
   ..12..

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 252 AM CDT SUN SEP 1 2013

TURNING COOLER WITH CONTINUED DRY CONDITIONS THROUGH THE WEEK.

OVERVIEW...INITIALIZATION AND VERIFICATION FAIR WITH NORMAL POOR
HANDLING OF BL MOISTURE AND ALSO SOME LOW LEVEL THERMAL FIELDS
DISCREPANCIES. VERIFICATION AND RUN TO RUN CONTINUITY SUGGEST A
50/50 MIX OF THE UKMET/GEM-RH WITH GFS. HI-RES ECMWF HAS SOME
CONTINUITY AND BL THERMAL FEEDBACK ISSUES. MINOR SENSIBLE WEATHER
ISSUES SINCE DRY. IF WASN/T FOR THE FACT WE NEED RAIN...THE
WEATHER THIS WEEK WILL BE ENJOYABLE.

MONDAY AND TUESDAY...COMFORTABLE AND REFRESHING EARLY FALL WEATHER
AS CANADIAN HIGH PRESSURE MOVES ACROSS THE REGION. HIGHS MIDDLE 70S
NORTH TO LOWER 80S FAR SOUTH. MINS MAY STILL NEED TRIMMING A DEGREE
OR TWO WITH LIGHT WINDS...CLEAR SKIES AND DRY GROUND FROM GOOD
RADIATIONAL COOLING CONDITIONS.

WEDNESDAY THROUGH SATURDAY...NW UPPER FLOW CONTINUES WITH WEAK HIGH
PRESSURE TO CONTINUE. LATER SHIFTS MAY BE ABLE TO GO COMPLETELY
DRY WEDNESDAY NIGHT IN FAR NW SECTIONS. HIGHS SHOULD RISE BACK
WELL INTO THE 80S WITH LOWS UPPER 50S TO MIDDLE 60S. OVERALL...SLIGHTLY
ABOVE NORMAL CONDITIONS WITH A SLIGHTLY HUMID BY NEXT WEEKEND BUT
HEAT INDICES STAYING AT OR BELOW 90 DEGREES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1150 PM CDT SAT AUG 31 2013

MAIN CHALLENGE REMAINS STRATUS/FOG POTENTIAL AND RAIN CHANCES OVERNIGHT
INTO SUNDAY.

LIGHT WIND AND ABUNDANT LOW LEVEL MOISTURE FAVORABLE FOR DEVELOPMENT
OF FOG OVERNIGHT WITH VISIBILITIES POTENTIALLY FLUCTUATING QUITE
A BIT SHALLOW LOW LEVEL INVERSION. THE RAP AND HRRR MODELS DO
INDICATE POTENTIAL FOR LIFR/VLIFR CONDITIONS ESPECIALLY EAST OF THE
MISSISSIPPI RIVER. INCREASING MID/HIGH CLOUDS OVERNIGHT AHEAD OF AN
APPROACHING COLD FRONT COULD HAVE IMPACT ON MAGNITUDE/EXTENT OF FOG
AND POSSIBLY EVEN SOME LOW CLOUDS...THUS WILL BE A CHALLENGING SET
OF TAFS. HAVE HIT THE FOG THE HARDEST WITH LIFR CONDITIONS AT KDBQ
WHERE RECENT RAINS PAST 24+ HRS. ELSEWHERE...HAVE IFR TO MVFR
VSBYS. COULD SEE SOME STRATUS WITH CIGS BLO 1KFT AGL AND HAVE
HINTED AT THIS STILL AT ALL SITES. ANTICIPATE SCATTERED SHOWERS
AND STORMS TO ACCOMPANY THE COLD FRONT...WHICH IS SLATED TO PASS
THROUGH THE TERMINALS FROM 13Z-19Z. CONDITIONS TO IMPROVE TO VFR
AFTER PASSAGE OF FRONT WITH WINDS INCREASING FROM NW AT 10-15 KTS
WITH GUSTS AROUND 18-22+ KTS DURING THE AFTERNOON...THEN DIMINISH
BLO 10 KTS BY 00Z.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SHORT TERM...12
LONG TERM...NICHOLS
AVIATION...05









AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 1200 AM CDT SUN SEP 1 2013

.SYNOPSIS...
ISSUED AT 223 PM CDT SAT AUG 31 2013

WEAK LOW PRESSURE OVER WEST CENTRAL IL EARLY THIS AFTERNOON. HOT
AND HUMID CONDITIONS WERE FOUND NEAR THE LOW WITH LOW TO MID 90
TEMPERATURES AND DEW POINTS IN THE LOW 70. IN THE LOW EASTERLY
FLOW NORTH OF THE LOW TEMPERATURES WERE COOLER BUT DEWPOINTS WERE
STILL AROUND 70. A COLD FRONT OVER THE NORTHERN PLAINS WAS THE
LEADING EDGE OF COOL DRY AIR MASS. EARLY AFTERNOON TEMPERATURES
OVER WESTERN NORTH DAKOTA WERE IN THE 70S WITH DEW POINTS IN THE 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 223 PM CDT SAT AUG 31 2013

THIS FORECAST PERIOD WILL SEE A TRANSITION TO A MUCH MORE
COMFORTABLE AIRMASS BY LATE SUNDAY AFTERNOON AS THE NORTHERN
PLAINS FRONT MOVES THROUGH THE REGION. RAIN CHANCES WILL ACCOMPANY
THE FRONT BUT AT THIS TIME...COVERAGE LOOKS SCATTERED AT BEST.

FOR TONIGHT THE AREA OF LOW PRESSURE OVER WEST CENTRAL IL WILL BE
THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON AND
THIS EVENING. IT APPEARS THAT THE DEVELOPMENT WILL TAKE PLACE JUST
EAST OF THE FORECAST AREA BASED CURRENT SATELLITE IMAGERY. HOWEVER
WITH AN UPSTREAM VORT...OVER NORTHWEST IL... EXPECT TO MOVE
THROUGH NORTHERN MO AND VERY UNSTABLE AIR STILL OVER THE SOUTHERN
COUNTIES...A LOW POP WAS MAINTAINED FOR THE EARLY EVENING HOURS.
WINDS WILL REMAIN LIGHT OVERNIGHT AND WITH THE HIGH DEWPOINTS
STILL IN PLACE WE COULD SEE SOME PATCHY FOG LATE ESPECIALLY EAST
OF THE MISSISSIPPI RIVER.

THE NORTHERN PLAINS COLD FRONT IS EXPECTED TO REACH THE NORTHWEST
CWA BY EARLY SUNDAY MORNING AND WILL EXIT THE EASTERN COUNTIES
DURING THE EARLY AFTERNOON. THE BETTER FORCING WITH THIS SYSTEM
WILL STAY OVER THE GREAT LAKES...BUT THE MODELS ARE SHOWING SOME
UPPER DIFFLUENCE AHEAD OF THE S/W MOVING OVER THE AREA WITH THE
COLD FRONT. THERE WILL ALSO BE OF NARROW THETAE RIDGE WITH THE
BOUNDARY AND STEEPENING MID LEVEL LAPSE RATES WHICH SHOULD BE
ENOUGH FOR SCATTERED STORMS AS THE FRONT MOVES THROUGH. COVERAGE
OF THE STORMS SHOULD INCREASE AS THE FRONT MOVES ACROSS THE
MISSISSIPPI RIVER WHERE THE AIRMASS HAS A CHANCE TO DESTABILIZE
DURING THE MORNING. THE THREAT OF SEVERE STORMS WILL BE LOW ON
SUNDAY DUE TO THE EARLY DAY FROPA AND WEAK DEEP LAYER SHEAR.

THE HIGH LOW LEVEL MOISTURE WILL KEEP MIN TEMPS IN THE MID 60S TO
AROUND 70 TONIGHT. HIGHS SUNDAY WILL STILL BE ON THE WARM SIDE
TOPPING OUT AROUND 90 SOUTH TO THE MID 80S IN THE NORTH...BUT WE
SHOULD SEE DEW POINTS COME DOWN A LITTLE...ESPECIALLY WEST OF THE
MISSISSIPPI RIVER.

DLF

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 223 PM CDT
SAT AUG 31 2013

ANY LINGERING RAIN ACROSS THE SOUTHEAST THIRD OF THE CWFA SUNDAY
EVENING WILL END SHORTLY AFTER SUNSET.

HIGH PRESSURE WILL MOVE ACROSS THE MIDWEST SUNDAY NIGHT THROUGH
TUESDAY RESULTING IN DRY BUT PLEASANT CONDITIONS. TEMPERATURES
SHOULD AVERAGE CLOSE TO NORMAL.

TUESDAY NIGHT ON...
NORTHWEST FLOW ALOFT WILL PERSIST THROUGH NEXT WEEKEND. SEVERAL
ADDITIONAL COLD FRONTS WILL MOVE THROUGH THE AREA BUT MOISTURE IS
EXPECTED TO BE LIMITED WITH EACH FRONTAL PASSAGE. WHILE NOT
CERTAIN...THE PROBABILITY IS MODERATE TO HIGH THAT MOST OF THE AREA
WILL REMAIN DRY.

THE MODEL CONSENSUS FOR TUESDAY NIGHT THROUGH SATURDAY IS FOR DRY
CONDITIONS THROUGH THE PERIOD WITH TEMPERATURES AVERAGING AT OR
SOMEWHAT ABOVE NORMAL.                      ..08..

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1150 PM CDT SAT AUG 31 2013

MAIN CHALLENGE REMAINS STRATUS/FOG POTENTIAL AND RAIN CHANCES OVERNIGHT
INTO SUNDAY.

LIGHT WIND AND ABUNDANT LOW LEVEL MOISTURE FAVORABLE FOR DEVELOPMENT
OF FOG OVERNIGHT WITH VISIBILITIES POTENTIALLY FLUCTUATING QUITE
A BIT SHALLOW LOW LEVEL INVERSION. THE RAP AND HRRR MODELS DO
INDICATE POTENTIAL FOR LIFR/VLIFR CONDITIONS ESPECIALLY EAST OF THE
MISSISSIPPI RIVER. INCREASING MID/HIGH CLOUDS OVERNIGHT AHEAD OF AN
APPROACHING COLD FRONT COULD HAVE IMPACT ON MAGNITUDE/EXTENT OF FOG
AND POSSIBLY EVEN SOME LOW CLOUDS...THUS WILL BE A CHALLENGING SET
OF TAFS. HAVE HIT THE FOG THE HARDEST WITH LIFR CONDITIONS AT KDBQ
WHERE RECENT RAINS PAST 24+ HRS. ELSEWHERE...HAVE IFR TO MVFR
VSBYS. COULD SEE SOME STRATUS WITH CIGS BLO 1KFT AGL AND HAVE
HINTED AT THIS STILL AT ALL SITES. ANTICIPATE SCATTERED SHOWERS
AND STORMS TO ACCOMPANY THE COLD FRONT...WHICH IS SLATED TO PASS
THROUGH THE TERMINALS FROM 13Z-19Z. CONDITIONS TO IMPROVE TO VFR
AFTER PASSAGE OF FRONT WITH WINDS INCREASING FROM NW AT 10-15 KTS
WITH GUSTS AROUND 18-22+ KTS DURING THE AFTERNOON...THEN DIMINISH
BLO 10 KTS BY 00Z.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...DLF
SHORT TERM...DLF
LONG TERM...08
AVIATION...05







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 244 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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1118 AM MDT SUN SEP 1 2013

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH KGLD AND
KMCK TERMINALS. NORTHEAST WINDS GUSTING TO 20KT WILL BE POSSIBLE
EARLY IN THE TAF BEFORE THE SURFACE GRADIENT BEGINS TO RELAX
BEHIND A COLD FRONT CURRENTLY SOUTH OF BOTH TERMINALS. BY MID
AFTERNOON WINDS SHOULD BE BELOW 12KT AT BOTH TERMINALS WITH LIGHT
AND VARIABLE WINDS OVERNIGHT. WINDS WILL SHIFT TO THE SOUTH AND
INCREASE ONCE AGAIN AROUND SUNRISE MONDAY MORNING IN RESPONSE TO
DEEPENING SURFACE TROUGH.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 207 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...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 214 AM MDT SUN SEP 1 2013

UPPER LEVEL BLOCKING PATTERN WILL CONTINUE OVER THE HIGH PLAINS FOR
THE EXTENDED FORECAST PERIOD...WHICH WILL KEEP WARM TEMPERATURES AND
DRY CONDITIONS OVER THE FORECAST AREA. THE 500 MB HIGH PRESSURE AREA
WILL BE CENTERED OVER COLORADO FOR WEDNESDAY AS RIDGE BECOMES MORE
AMPLIFIED INTO THE NORTHERN HIGH PLAINS FOR THURSDAY AND FRIDAY. THE
RIDGE WILL DEAMPLIFY AND RETROGRADE WESTWARD INTO THE DESERT
SOUTHWEST REGION NEXT WEEKEND AS AN UPPER LEVEL LOW MOVES OUT OF
ALBERTA AND ACROSS THE NORTHERN PLAINS. SHORTWAVE TROUGHS LOOK TO
DEVELOP LATE INTO NEXT WEEKEND AND MOVE INTO THE HIGH PLAINS WITH
THE MAIN ASSOCIATED UPPER LEVEL TROUGH...WHICH COULD PROVIDE
ENOUGH LIFT FOR THUNDERSTORM DEVELOPMENT FOR SUNDAY.

STRONG WARM AIR ADVECTION WILL CONTINUE AT THE SURFACE THROUGH THE
EXTENDED PERIOD...KEEPING SURFACE TEMPERATURES ABOVE AVERAGE IN THE
LOWER 90S. LOW TEMPERATURES FOR THE EXTENDED PERIOD WILL BE IN THE
UPPER 60S FOR MOST LOCATIONS. MODEL SOUNDINGS SHOW STABLE UPPER AIR
PROFILE THROUGH THE PERIOD...WITH MARGINAL INSTABILITY PARAMETERS AT
BEST AND A GENERAL LACK OF MOISTURE IN THE UPPER AIR PROFILES.
MODEL FORECASTS DIFFER ON PRECIPITATION CHANCES FOR NEXT
SUNDAY...BUT ENCROACHING FRONTAL CLIPPER SYSTEM WILL LIKELY
PROVIDE SOME CHANCES FOR STORM DEVELOPMENT. BESIDES SLIGHT
PRECIPITATION CHANCES NEXT WEEKEND...THE MAIN WEATHER PATTERN FOR
THE EXTENDED FORECAST PERIOD CONTINUES TO BE WARM TEMPERATURES AND
MAINLY DRY CONDITIONS FOR THE TRI STATE AREA.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1118 AM MDT SUN SEP 1 2013

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD AT BOTH KGLD AND
KMCK TERMINALS. NORTHEAST WINDS GUSTING TO 20KT WILL BE POSSIBLE
EARLY IN THE TAF BEFORE THE SURFACE GRADIENT BEGINS TO RELAX
BEHIND A COLD FRONT CURRENTLY SOUTH OF BOTH TERMINALS. BY MID
AFTERNOON WINDS SHOULD BE BELOW 12KT AT BOTH TERMINALS WITH LIGHT
AND VARIABLE WINDS OVERNIGHT. WINDS WILL SHIFT TO THE SOUTH AND
INCREASE ONCE AGAIN AROUND SUNRISE MONDAY MORNING IN RESPONSE TO
DEEPENING SURFACE TROUGH.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...MK
AVIATION...DR







AREA FORECAST DISCUSSION

NWS WICHITA KS

 1245 PM CDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 1108 AM CDT SUN SEP 1 2013

COOL FRONTAL BOUNDARY CONTINUES TO SLOWLY PUSH INTO SRN KS AT
THIS TIME. CURRENTLY LOCATED FROM KDDC-KPTT TO JUST SOUTH OF KICT
TO NEAR KCNU. SOME WIDELY SCT SHOWERS OR SPRINKLES ARE LOCATED
ALONG THE FRONT...WITH MORE WIDESPREAD SHOWERS OVER ERN KS. EXPECT
THIS FRONTAL BOUNDARY TO CONTINUE TO PUSH SOUTH INTO EXTREME SRN
KS EARLY THIS AFTERNOON...AND EVENTUALLY PUSH INTO OK BY LATE THIS
AFTERNOON/EARLY THIS EVENING. THE DRIER AIR ASSOCIATED WITH THIS
BOUNDARY IS LAGGING BEHIND SOMEWHAT...WITH SFC DEWPOINTS IN CEN KS
FALLING INTO THE LOW 60S. STILL SEEING SOME HIGHER SFC DWPTS OVER
SOUTHEAST KS...CLOSER TO THE MAIN BOUNDARY.

EXPECT THE MAIN SHORTWAVE OVER NE NEB TO DROP SOUTHEAST INTO ERN KS
AS THE AFTERNOON PROGRESSES. AS THIS INCREASED LIFT MOVES INTO SERN
KS...THINK SOME REINVIGORATED SHOWERS/STORMS WILL DEVELOP WHERE THIS
HIGHER SFC DWPT AIR AND UNSTABLE AIRMASS WILL BE LOCATED.  SO WILL
KEEP THE HIGHEST POPS ALONG THE KS/OK BORDER AND ESPECIALLY FOR SERN
KS FOR THE LATE AFTERNOON HOURS. THINK THERE IS A SMALL WINDOW OF
OPPORTUNITY FOR STORMS TO DEVELOP...AS THE DRIER AIR PUSHES INTO SRN
KS...AND EVENTUALLY WITH THE FRONT DROPPING SOUTH INTO OK. SO
THINK BY THE LATE AFTERNOON/EARLY EVENING HOURS...MOST OF THE
CONVECTIVE CHANCES WILL DROP SOUTH OF THE AREA INTO OK.  CURRENT
POPS/GRIDS HAVE THIS TREND WILL IN HAND...WITH ONLY SOME MINOR
TWEAKS FOR TIMING.

KETCHAM

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

APPARENT MCV OVER WEST-CENTRAL KS WAS DRIVING A BATCH OF CONVECTION
OVER SOUTHWEST KS EARLY THIS MORNING WHICH THE HRRR TRACKS
EAST-SOUTHEASTWARD WITH SOME WEAKENING TREND. OTHER STORM CLUSTERS
EXTENDED ALONG THE COLD FRONT FROM NORTH CENTRAL KANSAS TO EASTERN
NEBRASKA AND WERE MOVING SOUTHEAST. HAVE INCREASED STORM
PROBABILITIES IN CENTRAL KS THIS MORNING BASED ON LATEST RADAR
TRENDS. ISOLATED-WIDELY SCATTERED STORMS ARE POSSIBLE IN SOUTH
CENTRAL/SOUTHEAST KS.

THE COLD FRONT IS PROGGED TO BE PUSHING THROUGH CENTRAL KS AT
MIDDAY...THEN CLEARING FAR SOUTHEAST KS EARLY THIS EVE. WILL
MAINTAIN A 20-30% CHANCE OF STORMS THIS AFTERNOON IN THE SOUTH AS A
RESULT. SOME COOLER AIR WILL PUSH INTO CENTRAL KS TODAY BEHIND THE
FRONT...WITH HOT CONDITIONS IN THE FAR SOUTHERN COUNTIES JUST AHEAD
OF THE FRONT.

COOLER AND DRIER AIR WILL MOVE IN BEHIND THE FRONT TONIGHT INTO
TUESDAY WITH MORE SEASONABLE TEMPERATURES. THIS WILL MAKE FOR VERY
NICE WEATHER FOR LABOR DAY FOR THOSE WITH OUTDOOR PLANS.

JMC

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

THE UPPER HIGH CENTER WILL RE-STRENGTHEN OVER THE CENTRAL
ROCKIES/HIGH PLAINS WEDNESDAY INTO THURSDAY...THEN PERSISTING INTO
THE WEEKEND. THIS WILL LIKELY RESULT IN SLOWLY WARMING TEMPERATURES
TO ABOUT 5-10 DEGREES ABOVE NORMAL BY THE END OF THE WEEK. THE MAIN
RAIN CHANCES LOOK TO REMAIN NORTH AND EAST OF OUR FORECAST AREA...AS
VARIOUS SHORTWAVES RIDE OVERTOP OF AND AROUND THE UPPER HIGH.
THEREFORE...EXTENDED FORECAST CONTINUITY LOOKS ON TRACK AT THIS TIME.

JMC

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1244 PM CDT SUN SEP 1 2013

A WEAK COOL FRONT OVER SRN KS WILL CONTINUE TO PUSH SOUTH INTO OK
LATE THIS AFTERNOON. EXPECTING VFR CONDITIONS EVEN WITH THE CLOUD
COVER ACROSS THE AREA ASSOCIATED WITH THE BOUNDARY...WITH MOST
LOCATIONS ALREADY SEEING A WIND SHIFT TO THE NORTH OR NORTHEAST.

COULD ALSO SEE SOME SCATTERED SHRA FOR AREAS MAINLY EAST OF THE KS
TURNPIKE...WITH A FEW RUMBLES OF THUNDER POSSIBLE GIVEN SOME
LINGERING INSTABILITY IN THIS AREA. SO WILL GO WITH A VCTS FOR THE
KCNU TAF FOR THE AFTN HOURS. WILL SEE VFR CONDITIONS EVEN WITH THE
TSRA CHANCES.

THINK CHANCES OF TSRA WILL END QUICKLY AFTER 02Z/MON AS THE BOUNDARY
CONTINUES TO PUSH SOUTH INTO OK...WITH DRIER AIR PUSHING INTO MOST
LOCATIONS.  THIS DRIER AIR WILL ALSO LEAD TO A DIMINISHING CLOUD
TREND FOR MOST OF CEN KS LATE AFTN INTO THIS EVE.

KETCHAM

&&

.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT    90  64  88  64 / 100  10   0   0
HUTCHINSON      89  63  87  63 / 100  10   0   0
NEWTON          89  63  86  62 / 100  10   0   0
ELDORADO        90  64  86  62 /  90  10   0   0
WINFIELD-KWLD   95  65  89  64 /  30  10   0   0
RUSSELL         87  59  87  62 /  40   0   0   0
GREAT BEND      88  62  88  62 /  40   0   0   0
SALINA          89  61  87  62 /  30   0   0   0
MCPHERSON       89  62  87  62 /  30   0   0   0
COFFEYVILLE     95  66  88  64 /  30  10   0   0
CHANUTE         92  64  86  63 /  30  10   0   0
IOLA            91  63  86  62 /  30  10   0   0
PARSONS-KPPF    94  65  87  63 /  30  10   0   0

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS WICHITA KS

 1109 AM CDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 1108 AM CDT SUN SEP 1 2013

COOL FRONTAL BOUNDARY CONTINUES TO SLOWLY PUSH INTO SRN KS AT
THIS TIME. CURRENTLY LOCATED FROM KDDC-KPTT TO JUST SOUTH OF KICT
TO NEAR KCNU. SOME WIDELY SCT SHOWERS OR SPRINKLES ARE LOCATED
ALONG THE FRONT...WITH MORE WIDESPREAD SHOWERS OVER ERN KS. EXPECT
THIS FRONTAL BOUNDARY TO CONTINUE TO PUSH SOUTH INTO EXTREME SRN
KS EARLY THIS AFTERNOON...AND EVENTUALLY PUSH INTO OK BY LATE THIS
AFTERNOON/EARLY THIS EVENING. THE DRIER AIR ASSOCIATED WITH THIS
BOUNDARY IS LAGGING BEHIND SOMEWHAT...WITH SFC DEWPOINTS IN CEN KS
FALLING INTO THE LOW 60S. STILL SEEING SOME HIGHER SFC DWPTS OVER
SOUTHEAST KS...CLOSER TO THE MAIN BOUNDARY.

EXPECT THE MAIN SHORTWAVE OVER NE NEB TO DROP SOUTHEAST INTO ERN KS
AS THE AFTERNOON PROGRESSES. AS THIS INCREASED LIFT MOVES INTO SERN
KS...THINK SOME REINVIGORATED SHOWERS/STORMS WILL DEVELOP WHERE THIS
HIGHER SFC DWPT AIR AND UNSTABLE AIRMASS WILL BE LOCATED.  SO WILL
KEEP THE HIGHEST POPS ALONG THE KS/OK BORDER AND ESPECIALLY FOR SERN
KS FOR THE LATE AFTERNOON HOURS. THINK THERE IS A SMALL WINDOW OF
OPPORTUNITY FOR STORMS TO DEVELOP...AS THE DRIER AIR PUSHES INTO SRN
KS...AND EVENTUALLY WITH THE FRONT DROPPING SOUTH INTO OK. SO
THINK BY THE LATE AFTERNOON/EARLY EVENING HOURS...MOST OF THE
CONVECTIVE CHANCES WILL DROP SOUTH OF THE AREA INTO OK.  CURRENT
POPS/GRIDS HAVE THIS TREND WILL IN HAND...WITH ONLY SOME MINOR
TWEAKS FOR TIMING.

KETCHAM

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

APPARENT MCV OVER WEST-CENTRAL KS WAS DRIVING A BATCH OF CONVECTION
OVER SOUTHWEST KS EARLY THIS MORNING WHICH THE HRRR TRACKS
EAST-SOUTHEASTWARD WITH SOME WEAKENING TREND. OTHER STORM CLUSTERS
EXTENDED ALONG THE COLD FRONT FROM NORTH CENTRAL KANSAS TO EASTERN
NEBRASKA AND WERE MOVING SOUTHEAST. HAVE INCREASED STORM
PROBABILITIES IN CENTRAL KS THIS MORNING BASED ON LATEST RADAR
TRENDS. ISOLATED-WIDELY SCATTERED STORMS ARE POSSIBLE IN SOUTH
CENTRAL/SOUTHEAST KS.

THE COLD FRONT IS PROGGED TO BE PUSHING THROUGH CENTRAL KS AT
MIDDAY...THEN CLEARING FAR SOUTHEAST KS EARLY THIS EVE. WILL
MAINTAIN A 20-30% CHANCE OF STORMS THIS AFTERNOON IN THE SOUTH AS A
RESULT. SOME COOLER AIR WILL PUSH INTO CENTRAL KS TODAY BEHIND THE
FRONT...WITH HOT CONDITIONS IN THE FAR SOUTHERN COUNTIES JUST AHEAD
OF THE FRONT.

COOLER AND DRIER AIR WILL MOVE IN BEHIND THE FRONT TONIGHT INTO
TUESDAY WITH MORE SEASONABLE TEMPERATURES. THIS WILL MAKE FOR VERY
NICE WEATHER FOR LABOR DAY FOR THOSE WITH OUTDOOR PLANS.

JMC

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

THE UPPER HIGH CENTER WILL RE-STRENGTHEN OVER THE CENTRAL
ROCKIES/HIGH PLAINS WEDNESDAY INTO THURSDAY...THEN PERSISTING INTO
THE WEEKEND. THIS WILL LIKELY RESULT IN SLOWLY WARMING TEMPERATURES
TO ABOUT 5-10 DEGREES ABOVE NORMAL BY THE END OF THE WEEK. THE MAIN
RAIN CHANCES LOOK TO REMAIN NORTH AND EAST OF OUR FORECAST AREA...AS
VARIOUS SHORTWAVES RIDE OVERTOP OF AND AROUND THE UPPER HIGH.
THEREFORE...EXTENDED FORECAST CONTINUITY LOOKS ON TRACK AT THIS TIME.

JMC

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 640 AM CDT SUN SEP 1 2013

SCATTERED SHOWERS/THUNDERSTORMS ARE WEAKENING AT 12Z TAF ISSUANCE.
HAVE INCLUDED A BRIEF PERIOD OF -SHRA IN TEMPO GROUPS FOR KRSL AND
KSLN...BUT THE OUTLOOK FOR WIDESPREAD RAIN IS NOT GOOD. THE HRRR
CONTINUES TO DIMINISH THE PRECIPITATION  EXPANSE AS THE FRONT MOVES
SOUTHWARD. THUS...IF KHUT/KICT OR KCNU SEES PRECIPITATION AN
AMENDMENT WILL BE NEEDED.

THE FRONT IS JUST BEHIND THE MAIN CONVECTION/SHOWER LINE. WINDS
WILL SWITCH AROUND TO THE NORTH THIS MORNING AND ARE EXPECTED TO
STAY FROM THE NORTH SWITCHING FROM NORTHWEST TO NORTHEAST THROUGH
THE DAY. MID-HIGH CLOUDS WILL PERSIST UNTIL EVENING AS THE FRONT
EXITS TO THE SOUTH.  VFR CONDITIONS ARE EXPECTED TO PREVAIL.

BILLINGS


&&

.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT    90  64  88  64 / 100  10   0   0
HUTCHINSON      89  63  87  63 / 100  10   0   0
NEWTON          89  63  86  62 / 100  10   0   0
ELDORADO        90  64  86  62 /  90  10   0   0
WINFIELD-KWLD   95  65  89  64 /  30  10   0   0
RUSSELL         87  59  87  62 /  40   0   0   0
GREAT BEND      88  62  88  62 /  40   0   0   0
SALINA          89  61  87  62 /  30   0   0   0
MCPHERSON       89  62  87  62 /  30   0   0   0
COFFEYVILLE     95  66  88  64 /  30  10   0   0
CHANUTE         92  64  86  63 /  30  10   0   0
IOLA            91  63  86  62 /  30  10   0   0
PARSONS-KPPF    94  65  87  63 /  30  10   0   0

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS WICHITA KS

 640 AM CDT SUN SEP 1 2013

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

APPARENT MCV OVER WEST-CENTRAL KS WAS DRIVING A BATCH OF CONVECTION
OVER SOUTHWEST KS EARLY THIS MORNING WHICH THE HRRR TRACKS
EAST-SOUTHEASTWARD WITH SOME WEAKENING TREND. OTHER STORM CLUSTERS
EXTENDED ALONG THE COLD FRONT FROM NORTH CENTRAL KANSAS TO EASTERN
NEBRASKA AND WERE MOVING SOUTHEAST. HAVE INCREASED STORM
PROBABILITIES IN CENTRAL KS THIS MORNING BASED ON LATEST RADAR
TRENDS. ISOLATED-WIDELY SCATTERED STORMS ARE POSSIBLE IN SOUTH
CENTRAL/SOUTHEAST KS.

THE COLD FRONT IS PROGGED TO BE PUSHING THROUGH CENTRAL KS AT
MIDDAY...THEN CLEARING FAR SOUTHEAST KS EARLY THIS EVE. WILL
MAINTAIN A 20-30% CHANCE OF STORMS THIS AFTERNOON IN THE SOUTH AS A
RESULT. SOME COOLER AIR WILL PUSH INTO CENTRAL KS TODAY BEHIND THE
FRONT...WITH HOT CONDITIONS IN THE FAR SOUTHERN COUNTIES JUST AHEAD
OF THE FRONT.

COOLER AND DRIER AIR WILL MOVE IN BEHIND THE FRONT TONIGHT INTO
TUESDAY WITH MORE SEASONABLE TEMPERATURES. THIS WILL MAKE FOR VERY
NICE WEATHER FOR LABOR DAY FOR THOSE WITH OUTDOOR PLANS.

JMC

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

THE UPPER HIGH CENTER WILL RE-STRENGTHEN OVER THE CENTRAL
ROCKIES/HIGH PLAINS WEDNESDAY INTO THURSDAY...THEN PERSISTING INTO
THE WEEKEND. THIS WILL LIKELY RESULT IN SLOWLY WARMING TEMPERATURES
TO ABOUT 5-10 DEGREES ABOVE NORMAL BY THE END OF THE WEEK. THE MAIN
RAIN CHANCES LOOK TO REMAIN NORTH AND EAST OF OUR FORECAST AREA...AS
VARIOUS SHORTWAVES RIDE OVERTOP OF AND AROUND THE UPPER HIGH.
THEREFORE...EXTENDED FORECAST CONTINUITY LOOKS ON TRACK AT THIS TIME.

JMC

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 640 AM CDT SUN SEP 1 2013

SCATTERED SHOWERS/THUNDERSTORMS ARE WEAKENING AT 12Z TAF ISSUANCE.
HAVE INCLUDED A BRIEF PERIOD OF -SHRA IN TEMPO GROUPS FOR KRSL AND
KSLN...BUT THE OUTLOOK FOR WIDESPREAD RAIN IS NOT GOOD. THE HRRR
CONTINUES TO DIMINISH THE PRECIPITATION  EXPANSE AS THE FRONT MOVES
SOUTHWARD. THUS...IF KHUT/KICT OR KCNU SEES PRECIPITATION AN
AMENDMENT WILL BE NEEDED.

THE FRONT IS JUST BEHIND THE MAIN CONVECTION/SHOWER LINE. WINDS
WILL SWITCH AROUND TO THE NORTH THIS MORNING AND ARE EXPECTED TO
STAY FROM THE NORTH SWITCHING FROM NORTHWEST TO NORTHEAST THROUGH
THE DAY. MID-HIGH CLOUDS WILL PERSIST UNTIL EVENING AS THE FRONT
EXITS TO THE SOUTH.  VFR CONDITIONS ARE EXPECTED TO PREVAIL.

BILLINGS

&&

.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT    94  64  88  64 /  30  10   0   0
HUTCHINSON      92  63  87  63 /  40  10   0   0
NEWTON          92  63  86  62 /  40  10   0   0
ELDORADO        94  64  86  62 /  40  10   0   0
WINFIELD-KWLD   97  65  89  64 /  30  10   0   0
RUSSELL         89  59  87  62 /  40   0   0   0
GREAT BEND      90  62  88  62 /  40   0   0   0
SALINA          91  61  87  62 /  30   0   0   0
MCPHERSON       92  62  87  62 /  30   0   0   0
COFFEYVILLE     97  66  88  64 /  30  10   0   0
CHANUTE         94  64  86  63 /  30  10   0   0
IOLA            94  63  86  62 /  30  10   0   0
PARSONS-KPPF    96  65  87  63 /  30  10   0   0

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








AREA FORECAST DISCUSSION

NWS GOODLAND KS

 218 AM MDT SUN SEP 1 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 150 PM MDT SAT AUG 31 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW WEAKENED H5 RIDGE
EXTENDING ACROSS THE SW HALF OF THE CWA WITH WEST TO NORTHWEST FLOW
BEGINNING TO SHIFT SOUTH INTO SOUTHERN WYOMING AND MOST OF NEBRASKA.
A STRONG SHORTWAVE TROUGH HAS KICKED A COLD FRONT SOUTH TO THE NE
PANHANDLE. AHEAD OF THIS FEATURE WEAK MID LEVEL FRONTOGENETICAL
FORCING COMBINED WITH AN EXITING SHORTWAVE TROUGH OVER EASTERN
NEBRASKA LED TO LIGHT SHOWER/ISOLATED THUNDERSTORM DEVELOPMENT THIS
MORNING. LATEST RADAR TRENDS SHOW THIS ACTIVITY LINGERING OVER THE
CWA...WITH ADDITIONAL ACTIVITY DEVELOPING UPSTREAM OVER THE HIGHER
TERRAIN IN CENTRAL COLORADO AHEAD OF A WEAKER SHORTWAVE TROUGH OVER
EASTERN WYOMING.

AS THE SHORTWAVE TROUGH OVER WYOMING DROPS SOUTH TONIGHT IT WILL
HELP PUSH THE COLD FRONT SOUTH INTO NW KANSAS...WITH LARGE SCALE
FORCING OVERSPREADING OUR CWA. EARLY AFTERNOON SHOWER/THUNDERSTORM
ACTIVITY SHOULD INCREASE IN COVERAGE THROUGH 00Z IN RESPONSE TO THE
INCREASE IN LARGE SCALE SUPPORT AND FURTHER DESTABILIZATION. PWATS
REMAIN VERY HIGH THROUGH SUNDAY MORNING (1.3-1.5) SO THERE IS PLENTY
OF MOISTURE TO WORK WITH DURING THIS EVENT. AS SHORTWAVE DROPS SOUTH
THERE SHOULD BE AN INCREASE IN COVERAGE BEFORE SUBSIDENCE QUICKLY
MOVES IN FROM THE NORTH AFTER MIDNIGHT. MODELS DO SHOW COLD POOL
LINGERING IMMEDIATELY BEHIND COLD FRONT OVER OUR SOUTHERN CWA
THROUGH SUNDAY MORNING. THIS COLD POOL MAY ACTUALLY LINGER INTO THE
AFTERNOON...WHICH COULD HELP LEAD TO DIURNAL SHOWER/THUNDERSTORM
DEVELOPMENT BEFORE 00Z IN OUR SOUTH...SO I KEPT THUNDERSTORM MENTION
FOR THESE LOCATIONS.  BASED ON LATEST HRRR/RUC...I AM STILL UNSURE
ABOUT WHERE BEST COVERAGE WILL DEVELOP...HOWEVER ONGOING 40 POPS
SEEMED REASONABLE RIGHT. INSTABILITY MAY BE MARGINAL ACROSS MUCH OF
OUR CWA THROUGH TONIGHT...SO WE ARE PROBABLY ONLY LOOKING AT AN
ISOLATED SEVERE THUNDERSTORM THREAT.  WITH VERY MOIST AIR MASS AND
SLOW STORM MOTIONS I COULDNT HEAVY RAINFALL WITH ANY THUNDERSTORM
ACTIVITY. HOWEVER...I`M NOT SURE ABOUT HOW WIDESPREAD THAT THREAT
WILL REALLY BE. WE MAY JUST END UP WITH A GOOD THREAT OF LIGHT
RAIN...WITH A FEW ISOLATED POCKETS OF MODERATE-HEAVY RAINFALL.

REGARDING TEMPS...WITH CLEARING SKIES IN THE NORTH TEMPS HAVE
FINALLY BEGUN TO WARM ACROSS MUCH OF THE CWA...HOWEVER A DOWNWARD
ADJUSTMENT WAS NEEDED TO CATCH CURRENT TRENDS THIS AFTERNOON. AFTER
THE COLD FRONT PUSHES SOUTH TONIGHT A MUCH MORE SEASONABLE AIR MASS
WILL SETTLE OVER OUR CWA. HIGH ARE CURRENTLY PROGGED TO BE IN THE
MID-UPPER 80S SUNDAY...WHICH IS RIGHT ABOUT WHERE WE WOULD EXPECT TO
BE FOR LABOR DAY WEEKEND.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 214 AM MDT SUN SEP 1 2013

UPPER LEVEL BLOCKING PATTERN WILL CONTINUE OVER THE HIGH PLAINS FOR
THE EXTENDED FORECAST PERIOD...WHICH WILL KEEP WARM TEMPERATURES AND
DRY CONDITIONS OVER THE FORECAST AREA. THE 500 MB HIGH PRESSURE AREA
WILL BE CENTERED OVER COLORADO FOR WEDNESDAY AS RIDGE BECOMES MORE
AMPLIFIED INTO THE NORTHERN HIGH PLAINS FOR THURSDAY AND FRIDAY. THE
RIDGE WILL DEAMPLIFY AND RETROGRADE WESTWARD INTO THE DESERT
SOUTHWEST REGION NEXT WEEKEND AS AN UPPER LEVEL LOW MOVES OUT OF
ALBERTA AND ACROSS THE NORTHERN PLAINS. SHORTWAVE TROUGHS LOOK TO
DEVELOP LATE INTO NEXT WEEKEND AND MOVE INTO THE HIGH PLAINS WITH
THE MAIN ASSOCIATED UPPER LEVEL TROUGH...WHICH COULD PROVIDE
ENOUGH LIFT FOR THUNDERSTORM DEVELOPMENT FOR SUNDAY.

STRONG WARM AIR ADVECTION WILL CONTINUE AT THE SURFACE THROUGH THE
EXTENDED PERIOD...KEEPING SURFACE TEMPERATURES ABOVE AVERAGE IN THE
LOWER 90S. LOW TEMPERATURES FOR THE EXTENDED PERIOD WILL BE IN THE
UPPER 60S FOR MOST LOCATIONS. MODEL SOUNDINGS SHOW STABLE UPPER AIR
PROFILE THROUGH THE PERIOD...WITH MARGINAL INSTABILITY PARAMETERS AT
BEST AND A GENERAL LACK OF MOISTURE IN THE UPPER AIR PROFILES.
MODEL FORECASTS DIFFER ON PRECIPITATION CHANCES FOR NEXT
SUNDAY...BUT ENCROACHING FRONTAL CLIPPER SYSTEM WILL LIKELY
PROVIDE SOME CHANCES FOR STORM DEVELOPMENT. BESIDES SLIGHT
PRECIPITATION CHANCES NEXT WEEKEND...THE MAIN WEATHER PATTERN FOR
THE EXTENDED FORECAST PERIOD CONTINUES TO BE WARM TEMPERATURES AND
MAINLY DRY CONDITIONS FOR THE TRI STATE AREA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1100 PM MDT SAT AUG 31 2013

FOR KGLD AND KMCK VFR CONDITIONS EXPECTED. POST FRONTAL NORTHEAST
WINDS EXPECTED TO GUST CLOSE TO 25KTS OR SO AFTER 13Z-15Z THROUGH
20Z BEFORE DECREASING TOWARD 10KTS FROM THE EAST THEN LIGHT
EAST/SOUTHEAST 5KTS OR SO BY 02Z AS SFC HIGH MOVES IN. LATEST
MODELS HINTING AT SOME IFR CIGS FOR KGLD IN THE 12Z-16Z TIME FRAME.
HAVE INTRODUCED A SCATTERED GROUP AROUND 500FT TO ACCOUNT FOR THIS
AND WILL ALLOW NEXT SHIFT TO RE-EVALUATE POTENTIAL NEED FOR
PREVAILING IFR/VLIFR CONDITIONS. NO PRECIPITATION EXPECTED.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...MK
AVIATION...99







AREA FORECAST DISCUSSION

NWS WICHITA KS

 242 AM CDT SUN SEP 1 2013

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

APPARENT MCV OVER WEST-CENTRAL KS WAS DRIVING A BATCH OF CONVECTION
OVER SOUTHWEST KS EARLY THIS MORNING WHICH THE HRRR TRACKS
EAST-SOUTHEASTWARD WITH SOME WEAKENING TREND. OTHER STORM CLUSTERS
EXTENDED ALONG THE COLD FRONT FROM NORTH CENTRAL KANSAS TO EASTERN
NEBRASKA AND WERE MOVING SOUTHEAST. HAVE INCREASED STORM
PROBABILITIES IN CENTRAL KS THIS MORNING BASED ON LATEST RADAR
TRENDS. ISOLATED-WIDELY SCATTERED STORMS ARE POSSIBLE IN SOUTH
CENTRAL/SOUTHEAST KS.

THE COLD FRONT IS PROGGED TO BE PUSHING THROUGH CENTRAL KS AT
MIDDAY...THEN CLEARING FAR SOUTHEAST KS EARLY THIS EVE. WILL
MAINTAIN A 20-30% CHANCE OF STORMS THIS AFTERNOON IN THE SOUTH AS A
RESULT. SOME COOLER AIR WILL PUSH INTO CENTRAL KS TODAY BEHIND THE
FRONT...WITH HOT CONDITIONS IN THE FAR SOUTHERN COUNTIES JUST AHEAD
OF THE FRONT.

COOLER AND DRIER AIR WILL MOVE IN BEHIND THE FRONT TONIGHT INTO
TUESDAY WITH MORE SEASONABLE TEMPERATURES. THIS WILL MAKE FOR VERY
NICE WEATHER FOR LABOR DAY FOR THOSE WITH OUTDOOR PLANS.

JMC

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 239 AM CDT SUN SEP 1 2013

THE UPPER HIGH CENTER WILL RE-STRENGTHEN OVER THE CENTRAL
ROCKIES/HIGH PLAINS WEDNESDAY INTO THURSDAY...THEN PERSISTING INTO
THE WEEKEND. THIS WILL LIKELY RESULT IN SLOWLY WARMING TEMPERATURES
TO ABOUT 5-10 DEGREES ABOVE NORMAL BY THE END OF THE WEEK. THE MAIN
RAIN CHANCES LOOK TO REMAIN NORTH AND EAST OF OUR FORECAST AREA...AS
VARIOUS SHORTWAVES RIDE OVERTOP OF AND AROUND THE UPPER HIGH.
THEREFORE...EXTENDED FORECAST CONTINUITY LOOKS ON TRACK AT THIS TIME.

JMC

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1129 PM CDT SAT AUG 31 2013

A FRONTAL BOUNDARY WILL SINK SOUTHWARD INTO CENTRAL KANSAS TOWARDS
DAYBREAK...THEN PUSH SLOWLY SOUTHWARD INTO SOUTHERN KANSAS BY
SUNDAY AFTERNOON. A FEW THUNDERSTORMS WILL BE POSSIBLE ALONG THE
FRONTAL BOUNDARY.

JAKUB

&&

.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT    94  65  88  64 /  30  10   0   0
HUTCHINSON      92  64  87  63 /  40  10   0   0
NEWTON          92  64  86  62 /  30  10   0   0
ELDORADO        94  65  86  62 /  30  10   0   0
WINFIELD-KWLD   97  66  89  64 /  20  10   0   0
RUSSELL         89  60  87  62 /  40   0   0   0
GREAT BEND      90  63  88  62 /  40   0   0   0
SALINA          91  62  87  62 /  30   0   0   0
MCPHERSON       92  63  87  62 /  30   0   0   0
COFFEYVILLE     97  67  88  64 /  20  10   0   0
CHANUTE         94  65  86  63 /  30  10   0   0
IOLA            94  64  86  62 /  30  10   0   0
PARSONS-KPPF    96  66  87  63 /  20  10   0   0

&&

.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$





AREA FORECAST DISCUSSION...UPDATED

NWS DODGE CITY KS

 1243 AM CDT Sun Sep 1 2013

...Updated for Aviation...

.SYNOPSIS...
ISSUED AT 300 PM CDT SAT AUG 31 2013

An upper level center of high pressure was located across New Mexico
and the extreme southern High Plains today, as the upper westerly
jet was positioned zonally across the northern Rockies and Northern
Plains. A shortwave was in place across southern Canada, on the
north side of the jet. A hot airmass still encompassed the central
part of the country. 850 mb level temperatures in excess of 20
degrees C extended from the entire great plains region eastward to
the the Ohio valley. at the surface...a cold front was moving
southward across western South Dakota and extreme western Nebraska.
Another weak stationary front was positioned from the Texas
panhandle northeast into south central Kansas. Easterly surface
winds became more southerly across western Kansas as surface low
pressure slowly filled across the Oklahoma panhandle and temperatures
warmed into the 90`s by early afternoon.

&&

.SHORT TERM...(This evening through Sunday)
ISSUED AT 300 PM CDT SAT AUG 31 2013

The immediate concern will revolve around convective chances which
are not great, but non-zero as well. The best location appears along
the diffuse boundary across south central Kansas. The HRRR runs have
somewhat approximated isolated convection occurring by about 23 utc.
A lack of upper winds and lack of shear suggest little chances at
all of severe thunderstorms, and storms  should have short life
cycles. A better chance for showers and thunderstorms exists well
into the overnight as the Northern Plains cold front enters the
area. Probabilities increase from north to south around 6z and
after.

Very warm temperatures will continue into this evening. The NAM
models surface temperatures sill around 100 degrees this evening
near the Oklahoma line and low 80s persisting after midnight.
Morning lows will likely be warm across all of southwest Kansas,
with a few locations having lows in the upper 70s, however rain
cooled air form a few vigorous storm cluster might augment the
temperatures locally.

Thunderstorms chances are again in the forecast during the afternoon
Sunday as redevelopment is likely along the frontal boundary,
wherever it decides to stall out.

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 235 PM CDT SAT AUG 31 2013

A cold front will move across Kansas tonight as a vigorous upper
level trough moves from southeast Saskatchewan to the Great Lakes,
and a brief period of near climatological temperatures should extend
into Monday. However, the anticyclone centered over the Rockies will
build back into the Central Plains early next week, and several days
of warm, quiet weather will follow. Unless rainfall tonight is more
widespread than appears likely, vegetation will become increasingly
drought stressed next week. Reduced evapotranspiration may allow
more solar radiation to covert into sensible heat, and temperatures
in the mid to upper 90s can be expected on most days.

Tropical thunderstorm activity has been strongly suppressed from
about 130E to the dateline, although an area of enhanced
thunderstorms has been persistent in the Indian Ocean southwest of
India. Most of the numerical models suggest that a coherent tropical
cluster that projects onto a Madden Julian Oscillation (MJO) will
amplify in Phase 1 of the Wheeler-Hendon Phase Space Diagram early
in September and propagate slowly east before losing identity in the
Indian Ocean. There is little correlation between the MJO and
sensible weather in the central plains at this time of the year, but
there may be in increased chance for tropical waves to come off
Africa into the eastern Atlantic next week.

Global relative angular momentum remains below climatology, but
mountain torque has increased in recent days. The atmosphere will be
best represented by Phase 4-5 of the Weickmann-Berry Global Wind
Oscillation, which correlates with anticyclonic flow in the western
and central United States. The deterministic model solutions all
favor ridging from the central Rockies across the central and
southern United States through the first ten days of September with
only minor synoptic scale differences. The 12Z GFS has trended
toward the 00Z ECMWF in handling the closed cyclone near 140W that
wallows into the northern plains 9-10 September and largely was
followed for grid adjustments, although confidence in behavior of
this cyclone is low.

Upslope flow into the foothills in eastern Colorado Sunday evening
should favor thunderstorm development, but the upper level flow will
be light and largely meridional over western Kansas. Most of the
thunderstorms will remain west of the Colorado border, but there is
a nonzero chance that a thunderstorm could reach far southwest
Kansas before midnight Sunday night. Cool high pressure with light
winds and low level dewpoints in the 50s will allow for strong
radiational cooling, and lows will drop into the upper 50s in most
areas Tuesday morning. Another minor trough dropping into the mean
long wave trough near 80W will support a weak boundary that may
survive into northern Kansas Wednesday night, but limited
instability and weak flow aloft do not favor an organized
thunderstorm event. As the upper level trough near 140W moves across
the Northern Plains around 9 September, a cold front will move into
Kansas and provide another opportunity for thunderstorm development
and a return to more seasonal temperatures.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 1235 AM CDT SUN SEP 1 2013

Scattered thunderstorms at KDDC and KGCK with west to northwest
winds of 25-38kt will continue through 08-10z this morning, then
winds shifting to the northeast at 10-15kt after 15z. Vfr
conditions will prevail after the thunderstorms. KHYS will likely
stay out of the thunderstorm activity.

&&

.PRELIMINARY POINT TEMPS/POPS...
DDC  60  89  61  91 /  10   0   0   0
GCK  58  90  61  91 /  10   0   0   0
EHA  64  91  65  91 /  10  10  10   0
LBL  60  92  62  92 /  10   0   0   0
HYS  57  90  59  91 /   0   0   0   0
P28  64  90  62  91 /  10   0   0   0

&&

.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...Russell
SHORT TERM...Russell
LONG TERM...Ruthi
AVIATION...Kruse







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1102 PM MDT SAT AUG 31 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 150 PM MDT SAT AUG 31 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW WEAKENED H5 RIDGE
EXTENDING ACROSS THE SW HALF OF THE CWA WITH WEST TO NORTHWEST FLOW
BEGINNING TO SHIFT SOUTH INTO SOUTHERN WYOMING AND MOST OF NEBRASKA.
A STRONG SHORTWAVE TROUGH HAS KICKED A COLD FRONT SOUTH TO THE NE
PANHANDLE. AHEAD OF THIS FEATURE WEAK MID LEVEL FRONTOGENETICAL
FORCING COMBINED WITH AN EXITING SHORTWAVE TROUGH OVER EASTERN
NEBRASKA LED TO LIGHT SHOWER/ISOLATED THUNDERSTORM DEVELOPMENT THIS
MORNING. LATEST RADAR TRENDS SHOW THIS ACTIVITY LINGERING OVER THE
CWA...WITH ADDITIONAL ACTIVITY DEVELOPING UPSTREAM OVER THE HIGHER
TERRAIN IN CENTRAL COLORADO AHEAD OF A WEAKER SHORTWAVE TROUGH OVER
EASTERN WYOMING.

AS THE SHORTWAVE TROUGH OVER WYOMING DROPS SOUTH TONIGHT IT WILL
HELP PUSH THE COLD FRONT SOUTH INTO NW KANSAS...WITH LARGE SCALE
FORCING OVERSPREADING OUR CWA. EARLY AFTERNOON SHOWER/THUNDERSTORM
ACTIVITY SHOULD INCREASE IN COVERAGE THROUGH 00Z IN RESPONSE TO THE
INCREASE IN LARGE SCALE SUPPORT AND FURTHER DESTABILIZATION. PWATS
REMAIN VERY HIGH THROUGH SUNDAY MORNING (1.3-1.5) SO THERE IS PLENTY
OF MOISTURE TO WORK WITH DURING THIS EVENT. AS SHORTWAVE DROPS SOUTH
THERE SHOULD BE AN INCREASE IN COVERAGE BEFORE SUBSIDENCE QUICKLY
MOVES IN FROM THE NORTH AFTER MIDNIGHT. MODELS DO SHOW COLD POOL
LINGERING IMMEDIATELY BEHIND COLD FRONT OVER OUR SOUTHERN CWA
THROUGH SUNDAY MORNING. THIS COLD POOL MAY ACTUALLY LINGER INTO THE
AFTERNOON...WHICH COULD HELP LEAD TO DIURNAL SHOWER/THUNDERSTORM
DEVELOPMENT BEFORE 00Z IN OUR SOUTH...SO I KEPT THUNDERSTORM MENTION
FOR THESE LOCATIONS.  BASED ON LATEST HRRR/RUC...I AM STILL UNSURE
ABOUT WHERE BEST COVERAGE WILL DEVELOP...HOWEVER ONGOING 40 POPS
SEEMED REASONABLE RIGHT. INSTABILITY MAY BE MARGINAL ACROSS MUCH OF
OUR CWA THROUGH TONIGHT...SO WE ARE PROBABLY ONLY LOOKING AT AN
ISOLATED SEVERE THUNDERSTORM THREAT.  WITH VERY MOIST AIR MASS AND
SLOW STORM MOTIONS I COULDNT HEAVY RAINFALL WITH ANY THUNDERSTORM
ACTIVITY. HOWEVER...IM NOT SURE ABOUT HOW WIDESPREAD THAT THREAT
WILL REALLY BE. WE MAY JUST END UP WITH A GOOD THREAT OF LIGHT
RAIN...WITH A FEW ISOLATED POCKETS OF MODERATE-HEAVY RAINFALL.

REGARDING TEMPS...WITH CLEARING SKIES IN THE NORTH TEMPS HAVE
FINALLY BEGUN TO WARM ACROSS MUCH OF THE CWA...HOWEVER A DOWNWARD
ADJUSTMENT WAS NEEDED TO CATCH CURRENT TRENDS THIS AFTERNOON. AFTER
THE COLD FRONT PUSHES SOUTH TONIGHT A MUCH MORE SEASONABLE AIR MASS
WILL SETTLE OVER OUR CWA. HIGH ARE CURRENTLY PROGGED TO BE IN THE
MID-UPPER 80S SUNDAY...WHICH IS RIGHT ABOUT WHERE WE WOULD EXPECT TO
BE FOR LABOR DAY WEEKEND.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 204 PM MDT SAT AUG 31 2013

THE UPPER RIDGE IS IN PLACE AGAIN OVER THE ROCKIES AND HIGH PLAINS
FROM SUNDAY NIGHT THROUGH ALL OF NEXT WEEK. DIFFERENCES BEGIN TO
SHOW UP IN MODEL PROGRESSIONS OF THE UPPER LOW CENTER RIDING UP
OVER THE RIDGE IN THE PACIFIC NORTHWEST AND THE OVERALL FLATTENING
OF THE RIDGE IN THE FRIDAY NIGHT THROUGH SATURDAY TIME PERIOD.

SURFACE COOLER HIGH PRESSURE AREA STAYS MOSTLY OVER THE CENTRAL
PLAINS AND CENTRAL HIGH PLAINS SUNDAY NIGHT AND MONDAY BEFORE
PUSHING FURTHER EAST WITH A DEEPENING LEE TROUGH THAT PERSISTS IN
THE VICINITY OF THE EASTERN COLORADO BORDER. WITH SOUTHERLY FLOW
ACROSS THE FORECAST AREA...EXPECT MORE DRY AND WARM CONDITIONS
THROUGH THE UPCOMING WORK WEEK AND NEXT WEEKEND WITH HIGHS IN THE
90S AND LOWS IN THE 60S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1100 PM MDT SAT AUG 31 2013

FOR KGLD AND KMCK VFR CONDITIONS EXPECTED. POST FRONTAL NORTHEAST
WINDS EXPECTED TO GUST CLOSE TO 25KTS OR SO AFTER 13Z-15Z THROUGH
20Z BEFORE DECREASING TOWARD 10KTS FROM THE EAST THEN LIGHT
EAST/SOUTHEAST 5KTS OR SO BY 02Z AS SFC HIGH MOVES IN. LATEST
MODELS HINTING AT SOME IFR CIGS FOR KGLD IN THE 12Z-16Z TIMEFRAME.
HAVE INTRODUCED A SCATTERED GROUP AROUND 500FT TO ACCOUNT FOR THIS
AND WILL ALLOW NEXT SHIFT TO RE-EVALUATE POTENTIAL NEED FOR
PREVAILING IFR/VLIFR CONDITIONS. NO PRECIPITATION EXPECTED.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...99







AREA FORECAST DISCUSSION

NWS PADUCAH KY

 1236 PM CDT Sun Sep 1 2013

.UPDATE...
ISSUED AT 1235 PM CDT SUN SEP 1 2013

Beginning to be concerned for severe weather potential across
southern Illinois this afternoon. Although the original convection
moving through central Missouri has dissipated, the convective
mesoscale vort center is now very obviously moving east southeast
toward our region, and a few strong cells have developed just
ahead it just southwest St Louis. Lots of sunshine and warming
over the northern half of the southern Illinois should provide
plenty of instability for the convectively generate disturbance to
work with this afternoon. Increased pops to around 40 percent for
scattered storms over much of southern Illinois. Also backed off
temperatures a few degrees over much of southern Illinois and the
Evansville Tri State area.

UPDATE ISSUED AT 1212 PM CDT SUN SEP 1 2013

Update for 18z aviation.

UPDATE ISSUED AT 1208 PM CDT SUN SEP 1 2013

Major update to all public products has just been sent. Looks like
southeast Missouri may see scattered showers and thunderstorms
through much of the day, as west southwesterly low-level flow
continues to bang into the old outflow boundary. The severe storm
complex over central Missouri is finally weakening, and would
expect that trend to continue per the latest HRRR forecast. May
see some anvil debris spread into our northwest counties through
early afternoon, but do not expect this area to bodily move into
our region this afternoon.

The other concern is the Heat Advisory. Used a combination of the
HRRR, which has a decent handle on the hot temperatures in the
sunny northern portions of the area, and the 00Z ARW WRF which has
the best handle I could find on the clouds, convection and
temperatures over the south/southwest.

Tried to indicate some decrease in cloud cover over the southwest,
but kept temperatures in the middle 80s. Of course if the
convection continues to stream over that area, the associated
cloud cover may hold them down even more. Feel that the chance of
a massive outbreak of sunshine over in that area is not likely, so
have removed much of that area from the Heat Advisory.

Over the north, not sure how much of an impact last night`s
convection will have on high temperature potential with plentiful
sunshine this afternoon. Decided to use the HRRR as a guide and
go with mid 90s over this area, which leads to heat indices in the
100 to 105 range.

Further adjustments will likely be needed this afternoon, so stay
tuned. Also, not sure what impact the persistent Missouri
convection will have on the thunderstorm potential across the area
tonight.

&&

.SHORT TERM...(Today through Tuesday Night)
ISSUED AT 306 AM CDT SUN SEP 1 2013

A slight challenge with forecast package through 7 am CDT, as
decent southwesterly flow aiding in decent surface thet-a
convergence along western edge of complex. This should support
renewed convective cell development westward along the upshear
component over the expanding cold pool. The NAM-WRF and SREF
guidance hint at this feature and continue to extend precipitation
chances to the south and west through the morning hours. As CAPE
increases duri9ng the afternoon, the focus of convection should
shift to just south of the frontal boundary by late afternoon,
aided by differential heating.

For tonight, was a little more generous with the coverage and PoPs
during the evening and early overnight hours. Once the forcing and
instability shift southward before daybreak on Monday, rain
chances should drop off quite rapidly along with significant
clearing.

The remainder of the short term forecast period should be dry and
slightly cooler as northerly flow builds into the region.

The last day of the heat advisory still looks good. Heat index
values should spike into the low 100`s between 1 pm and 6 pm CDT
ahead of the frontal boundary. See no reason to adjust the current
advisory in effect.

Anticipate the greatest severe threat will be late this afternoon and
into the early evening over Southern IL/Southeast MO. Main concern
for the remainder of the pre-dawn hours will be locally heavy
rain and isolated strong winds gusts.

.LONG TERM...(Wednesday through Saturday)
ISSUED AT 306 AM CDT SUN SEP 1 2013

The mid level flow pattern will be more typical of what we have
seen much of the summer, with the mean trof position over the east
CONUS and the ridge over the west U.S. Generally dry weather is
expected with temperatures slowly moderating each day back toward
normal for this time of year. A front is forecast to backdoor the
area Thur/Fri. But moisture profiles in both the GFS and ECMWF are
not too impressive at this time.

&&

.AVIATION...
ISSUED AT 1209 PM CDT SUN SEP 1 2013

Placed thunder mention in kevv and kowb for this afternoon with
clearing skies and mcv headed that way could see storms pre
frontal. Kept mention of thunder tonight for fropa all sites.
Low confidence in timing and coverage of precip. Also have wind
shift this evening for fropa and some fog mention mainly at kevv
and kowb due to the heavy rain that had already fallen there.


&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY until 6 PM CDT this evening FOR ILZ075>078-080>091.

MO...HEAT ADVISORY until 6 PM CDT this evening FOR MOZ076.

IN...HEAT ADVISORY until 6 PM CDT this evening FOR INZ081-082-085>088.

KY...HEAT ADVISORY until 6 PM CDT this evening FOR KYZ007-010-013>016-
     018>020.

&&

$$

UPDATE...DRS
SHORT TERM...Smith
LONG TERM...CN
AVIATION...KH







AREA FORECAST DISCUSSION

NWS PADUCAH KY

 1212 PM CDT Sun Sep 1 2013

.UPDATE...
ISSUED AT 1208 AM CDT SUN SEP 1 2013

Update for 18z aviation.

Major update to all public products has just been sent. Looks like
southeast Missouri may see scattered showers and thunderstorms
through much of the day, as west southwesterly low-level flow
continues to bang into the old outflow boundary. The severe storm
complex over central Missouri is finally weakening, and would
expect that trend to continue per the latest HRRR forecast. May
see some anvil debris spread into our northwest counties through
early afternoon, but do not expect this area to bodily move into
our region this afternoon.

The other concern is the Heat Advisory. Used a combination of the
HRRR, which has a decent handle on the hot temperatures in the
sunny northern portions of the area, and the 00Z ARW WRF which has
the best handle I could find on the clouds, convection and
temperatures over the south/southwest.

Tried to indicate some decrease in cloud cover over the southwest,
but kept temperatures in the middle 80s. Of course if the
convection continues to stream over that area, the associated
cloud cover may hold them down even more. Feel that the chance of
a massive outbreak of sunshine over in that area is not likely, so
have removed much of that area from the Heat Advisory.

Over the north, not sure how much of an impact last night`s
convection will have on high temperature potential with plentiful
sunshine this afternoon. Decided to use the HRRR as a guide and
go with mid 90s over this area, which leads to heat indices in the
100 to 105 range.

Further adjustments will likely be needed this afternoon, so stay
tuned. Also, not sure what impact the persistent Missouri
convection will have on the thunderstorm potential across the area
tonight.

&&

.SHORT TERM...(Today through Tuesday Night)
ISSUED AT 306 AM CDT SUN SEP 1 2013

A slight challenge with forecast package through 7 am CDT, as
decent southwesterly flow aiding in decent surface thet-a
convergence along western edge of complex. This should support
renewed convective cell development westward along the upshear
component over the expanding cold pool. The NAM-WRF and SREF
guidance hint at this feature and continue to extend precipitation
chances to the south and west through the morning hours. As CAPE
increases duri9ng the afternoon, the focus of convection should
shift to just south of the frontal boundary by late afternoon,
aided by differential heating.

For tonight, was a little more generous with the coverage and PoPs
during the evening and early overnight hours. Once the forcing and
instability shift southward before daybreak on Monday, rain
chances should drop off quite rapidly along with significant
clearing.

The remainder of the short term forecast period should be dry and
slightly cooler as northerly flow builds into the region.

The last day of the heat advisory still looks good. Heat index
values should spike into the low 100`s between 1 pm and 6 pm CDT
ahead of the frontal boundary. See no reason to adjust the current
advisory in effect.

Anticipate the greatest severe threat will be late this afternoon and
into the early evening over Southern IL/Southeast MO. Main concern
for the remainder of the pre-dawn hours will be locally heavy
rain and isolated strong winds gusts.

.LONG TERM...(Wednesday through Saturday)
ISSUED AT 306 AM CDT SUN SEP 1 2013

The mid level flow pattern will be more typical of what we have
seen much of the summer, with the mean trof position over the east
CONUS and the ridge over the west U.S. Generally dry weather is
expected with temperatures slowly moderating each day back toward
normal for this time of year. A front is forecast to backdoor the
area Thur/Fri. But moisture profiles in both the GFS and ECMWF are
not too impressive at this time.

&&

.AVIATION...
ISSUED AT 1209 PM CDT SUN SEP 1 2013

Placed thunder mention in kevv and kowb for this afternoon with
clearing skies and mcv headed that way could see storms pre
frontal. Kept mention of thunder tonight for fropa all sites.
Low confidence in timing and coverage of precip. Also have wind
shift this evening for fropa and some fog mention mainly at kevv
and kowb due to the heavy rain that had already fallen there.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY until 6 PM CDT this evening FOR ILZ075>078-080>091.

MO...HEAT ADVISORY until 6 PM CDT this evening FOR MOZ076.

IN...HEAT ADVISORY until 6 PM CDT this evening FOR INZ081-082-085>088.

KY...HEAT ADVISORY until 6 PM CDT this evening FOR KYZ007-010-013>016-
     018>020.

&&

$$

UPDATE...DRS
SHORT TERM...Smith
LONG TERM...CN
AVIATION...KH







AREA FORECAST DISCUSSION

NWS PADUCAH KY

 1108 AM CDT Sun Sep 1 2013

.UPDATE...
ISSUED AT 1108 AM CDT SUN SEP 1 2013

Major update to all public products has just been sent. Looks like
southeast Missouri may see scattered showers and thunderstorms
through much of the day, as west southwesterly low-level flow
continues to bang into the old outflow boundary. The severe storm
complex over central Missouri is finally weakening, and would
expect that trend to continue per the latest HRRR forecast. May
see some anvil debris spread into our northwest counties through
early afternoon, but do not expect this area to bodily move into
our region this afternoon.

The other concern is the Heat Advisory. Used a combination of the
HRRR, which has a decent handle on the hot temperatures in the
sunny northern portions of the area, and the 00Z ARW WRF which has
the best handle I could find on the clouds, convection and
temperatures over the south/southwest.

Tried to indicate some decrease in cloud cover over the southwest,
but kept temperatures in the middle 80s. Of course if the
convection continues to stream over that area, the associated
cloud cover may hold them down even more. Feel that the chance of
a massive outbreak of sunshine over in that area is not likely, so
have removed much of that area from the Heat Advisory.

Over the north, not sure how much of an impact last night`s
convection will have on high temperature potential with plentiful
sunshine this afternoon. Decided to use the HRRR as a guide and
go with mid 90s over this area, which leads to heat indices in the
100 to 105 range.

Further adjustments will likely be needed this afternoon, so stay
tuned. Also, not sure what impact the persistent Missouri
convection will have on the thunderstorm potential across the area
tonight.

&&

.SHORT TERM...(Today through Tuesday Night)
ISSUED AT 306 AM CDT SUN SEP 1 2013

A slight challenge with forecast package through 7 am CDT, as
decent southwesterly flow aiding in decent surface thet-a
convergence along western edge of complex. This should support
renewed convective cell development westward along the upshear
component over the expanding cold pool. The NAM-WRF and SREF
guidance hint at this feature and continue to extend precipitation
chances to the south and west through the morning hours. As CAPE
increases duri9ng the afternoon, the focus of convection should
shift to just south of the frontal boundary by late afternoon,
aided by differential heating.

For tonight, was a little more generous with the coverage and PoPs
during the evening and early overnight hours. Once the forcing and
instability shift southward before daybreak on Monday, rain
chances should drop off quite rapidly along with significant
clearing.

The remainder of the short term forecast period should be dry and
slightly cooler as northerly flow builds into the region.

The last day of the heat advisory still looks good. Heat index
values should spike into the low 100`s between 1 pm and 6 pm CDT
ahead of the frontal boundary. See no reason to adjust the current
advisory in effect.

Anticipate the greatest severe threat will be late this afternoon and
into the early evening over Southern IL/Southeast MO. Main concern
for the remainder of the pre-dawn hours will be locally heavy
rain and isolated strong winds gusts.

.LONG TERM...(Wednesday through Saturday)
ISSUED AT 306 AM CDT SUN SEP 1 2013

The mid level flow pattern will be more typical of what we have
seen much of the summer, with the mean trof position over the east
CONUS and the ridge over the west U.S. Generally dry weather is
expected with temperatures slowly moderating each day back toward
normal for this time of year. A front is forecast to backdoor the
area Thur/Fri. But moisture profiles in both the GFS and ECMWF are
not too impressive at this time.

&&

.AVIATION...
ISSUED AT 709 AM CDT SUN SEP 1 2013

With the 12z Sunday TAF issuance, kept all of the WFO PAH TAF
sites in VFR category at this time. Until convective activity
appears later on this afternoon and this evening, it is difficult
to pinpoint at this time for lowered visibilities and ceilings.
Utilized vicinity thunderstorm to approximate the time for
convective activity near the sites. Slightly lower cloud decks or
MVFR visibilities were added the KEVV/KOWB TAF`s to account for
the approach of the frontal boundary.


&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY until 6 PM CDT this evening FOR ILZ075>078-080>091.

MO...HEAT ADVISORY until 6 PM CDT this evening FOR MOZ076.

IN...HEAT ADVISORY until 6 PM CDT this evening FOR INZ081-082-085>088.

KY...HEAT ADVISORY until 6 PM CDT this evening FOR KYZ007-010-013>016-
     018>020.

&&

$$

UPDATE...DRS
SHORT TERM...Smith
LONG TERM...CN
AVIATION...Smith







AREA FORECAST DISCUSSION...UPDATED

NWS JACKSON KY

 1107 AM EDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 1107 AM EDT SUN SEP 1 2013

PLENTIFUL CLOUD COVER OF VARYING HEIGHTS REMAINS IN THE WAKE OF THE
OVERNIGHT AND EARLY MORNING CONVECTION. MOST OF THE SHORT RANGE MODEL
DATA SUGGESTS THAT TODAY WILL BE MUCH LESS ACTIVE THIS AFTERNOON
COMPARED TO YESTERDAY. AS SUCH...HAVE LOWERED POPS TO LOW CHANCE FOR
MOST LOCATIONS AND HAVE ONLY MENTIONED ISOLATED THUNDERSTORM CHANCES
FOR THIS AFTERNOON. CLOUDS WILL GRADUALLY THIN WITH TIME...HOWEVER
DID NUDGE THE HIGH TEMPERATURES DOWN A TAD WITH THE SLOW START THIS
MORNING. CONSEQUENTLY...WENT AHEAD AND TEMPERED THE DIURNAL RISE A
BIT MORE AS WELL.

UPDATE ISSUED AT 750 AM EDT SUN SEP 1 2013

UPDATED THE POP AND WX GRIDS TO REFLECT THE WANING OF THE SHOWERS AND
THUNDERSTORMS ACROSS OUR SOUTH. ALSO FINE TUNED THE NEAR TERM T/TD
GRIDS IN LINE WITH THE OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS. A FRESHENED SET OF ZONES WILL FOLLOW.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 440 AM EDT SUN SEP 1 2013

07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING INTO THE OHIO
VALLEY FROM THE CENTRAL PLAINS. THIS...IN CONJUNCTION WITH AN MCV...
CONTINUES TO DEVELOP CONVECTION OVER NORTHWESTERN/CENTRAL KENTUCKY
AND DRIFT IT SOUTHEAST INTO THE CUMBERLAND VALLEY. THE RAINS FROM
THIS COULD BE EXCESSIVE OVER PARTS OF WAYNE AND PULASKI COUNTIES
PROMPTING A CONTINUATION OF THE URBAN AND SMALL STREAM FLOOD
ADVISORIES FOR THESE LOCATIONS. IF THE RATES PICK UP IN THE NEXT
ROUND OF CONVECTION WE WILL NEED TO CONSIDER FLOOD WARNINGS...BUT SO
FAR THESE HAVE BEEN LIGHT ENOUGH TO JUST MAINTAIN THE ADVISORIES.
OTHERWISE...MOSTLY CLOUDY SKIES COVER EAST KENTUCKY KEEPING THE FOG
PATCHY AND LIGHT FOR MOST OF THE AREA. THIS IS DESPITE ANOTHER NIGHT
OF MINIMAL DEW POINT DEPRESSIONS WITH TEMPS AND DEWS HOLDING IN THE
UPPER 60S...MUCH OF THIS THE RESULT OF RAIN COOLING EARLIER IN THE
NIGHT.

THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH THE NORTHWEST FLOW REGIME
OVER THE OHIO VALLEY AMPLIFYING IN RESPONSE TO A TROUGH PASSING
THROUGH THE NORTHERN GREAT LAKES TODAY THROUGH MONDAY. THIS TROUGH
WILL SEND PLENTY OF SHORTWAVE ENERGY INTO OUR AREA DURING THIS TIME
WITH THE MESOSCALE DOMINANT FOR SENSIBLE WEATHER. ACCORDINGLY...HAVE
USED THE NAM12 TO GUIDE THIS FORECAST IN COORDINATION WITH THE LATEST
HRRR AND CURRENT LARGER SCALE RADAR TRENDS.

SENSIBLE WEATHER WILL BE A CONTINUATION OF OUR WARM...HUMID...AND
STORMY HOLIDAY WEEKEND. CONVECTION IS ANTICIPATED OVER OUR SOUTHERN
AND WESTERN ZONES EARLY THIS MORNING GRADUALLY FADING OUT BEFORE
ANOTHER ROUND DEVELOPS LATER TODAY. THE STRONGEST STORMS COULD
CONTAIN GUSTY TO DAMAGING WINDS IF THEY GET TALL ENOUGH...BOW OR
MERGE. A VEERING WIND PROFILE AND SOME MID LEVEL SPEED SHEAR ALSO
SUPPORTS THIS CONCERN. OTHERWISE...THE MAIN ISSUE WILL BE EXCESSIVE
RAINFALL AND FLOODING POTENTIAL GIVEN THE RAINS THAT HAVE FALLEN AND
THE THREAT OF ADDITIONAL CONVECTION TRAINING OVER THE SAME AREAS.
CANNOT RULE OUT THE SCATTERED CONVECTION CONTINUING INTO THE NIGHT
WITH LOW PRESSURE IN PLACE OVER THE REGION AND THE APPROACH OF ITS
COLD FRONT...THOUGH THE NAM12 WOULD SUGGEST A LULL UNTIL LATER MONDAY
MORNING. HAVE RAMPED POPS DOWN DURING THIS TIME IN THE GRIDS...BUT
NOT AS MUCH AS THE NAM12 INDICATES. FOR MONDAY...THE SYSTEM/S FRONT
WILL MAKE A MORE DEFINITIVE PUSH INTO OUR AREA AND LIKELY ACTIVATE
THE REMAINING DEEP MOISTURE FOR ONE LAST GOOD ROUND OF CONVECTION
DURING THE DAY. TEMPERATURES WILL BE DEPENDENT ON CONVECTION...
PARTICULARLY FOR HIGHS TODAY AND TOMORROW...BUT IN GENERAL SHOULD BE
ABLE TO REACH THE MID AND UPPER 80S. AGAIN UPPER 60S WILL BE THE RULE
FOR LOWS TONIGHT.

USED THE CONSSHORT AND ITS BC VERSION FOR THE DEW POINT AND WIND
GRIDS...RESPECTIVELY...THROUGH 00Z MONDAY AS A STARTING POINT AND THE
CONSALL THEREAFTER. FOR TEMPS...ADJUSTED THE CONSALL FOR SOME MINOR
TERRAIN ENHANCEMENTS IN THE LOWS TONIGHT AND PCPN CONSIDERATIONS
TODAY AND MONDAY...WITH HOURLY DIURNAL CURVE DERIVED FROM THE NAM12.
AS FOR POPS...ENDED UP CLOSER TO THE WETTER MAV GUIDANCE TODAY...
SIMILAR TO BOTH TONIGHT...AND THEN NEARER THE MET MONDAY.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 AM EDT SUN SEP 1 2013

A STRONG SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES AT THE START
OF THE PERIOD WILL PUT THE OHIO RIVER VALLEY IN A TROUGHING PATTERN.
AT THE SURFACE...AN ASSOCIATED LOW PRESSURE SYSTEM WILL GENERATE A
COLD FRONT WHICH SHOULD JUST BE EXITING EASTERN KY AT THE BEGINNING
OF THE PERIOD. THE FROPA WILL PRODUCE SHOWERS AND THUNDERSTORMS IN
THE WARM SECTOR...WHICH SHOULD BE PUSHING OUT OF THE REGION BY
TUESDAY MORNING. THE SHORTWAVE WILL CONTINUE EASTWARD THROUGHOUT THE
DAY TUESDAY...WITH HIGH PRESSURE RIDGING TAKING HOLD ACROSS KY. THIS
WILL MEAN THE RETURN OF A MUCH COOLER AND DRIER AIR MASS...WITH WINDS
AT THE MID AND UPPER LEVELS OUT OF THE NE. HIGH TEMPS WILL ONLY
REACH NEAR 80 TUESDAY.

THIS UPPER AIR PATTERN AND SURFACE HIGH PRESSURE WILL PERSIST
THROUGH THE REMAINDER OF THE WEEK...WITH ABUNDANT SUNSHINE ALLOWING
TEMPS TO RISE SLIGHTLY INTO THE LOWS 80S. WITH A DRY AIR MASS IN
PLACE...DIURNAL COOLING WILL ALLOW OVERNIGHT TEMPS TO FALL INTO THE
50S. WHILE MODELS START TO DIVERGE ON UPPER AIR SOLUTIONS BY THE END
OF THE PERIOD...THERE IS STILL SOME CONSENSUS OF ANOTHER UPPER LEVEL
SHORTWAVE DEVELOPING OVER NE CANADA FRIDAY NIGHT INTO SATURDAY. AT
THIS SURFACE THIS WILL TRANSLATE TO A LOW PRESSURE SYSTEM OVER NE
CANADA...WITH A COLD FRONT POISED TO DROP SOUTHWARD FROM THE UPPER
GREAT LAKES SATURDAY. ACCORDING THE ECMWF...WARM AIR PULLING IN
AHEAD OF THIS FRONT...COUPLED WITH DAYTIME HEATING...WILL LEAD TO
THE DEVELOPMENT OF SCT CONVECTION. HOWEVER...WILL STICK WITH A MODEL
CONSENSUS FOR SATURDAY AND SUNDAY...SINCE THIS FAR OUT THE EXACT
COURSE OF THE TROUGHING AND ASSOCIATED COLD FRONT/PRECIP IS STILL
SOMEWHAT UNKNOWN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 800 AM EDT SUN SEP 1 2013

THE LATEST ROUND OF THUNDERSTORMS HAVE TAPERED TO SHOWERS THROUGH
THE CUMBERLAND VALLEY. DO STILL EXPECT SOME ADDITIONAL STORMS TO
DEVELOP AND AFFECT THE AREA LATER IN THE DAY BUT HAVE BACKED THESE
OFF TO JUST VCTS MENTIONS GIVEN THE LATEST HRRR AND NAM12 MODEL
GUIDANCE SHOWING MORE OF A DRY PERIOD IN THE WAKE OF THE MORNING
STORMS. THE REDEVELOPMENT WILL LIKEWISE FADE OUT LATER THIS EVENING
AND PATCHY MVFR FOG CAN BE ANTICIPATED AFTER 06Z AT MOST SITES.
WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE...OUTSIDE OF ANY
STORMS.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GEOGERIAN
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF







AREA FORECAST DISCUSSION...UPDATED

NWS JACKSON KY

 800 AM EDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 750 AM EDT SUN SEP 1 2013

UPDATED THE POP AND WX GRIDS TO REFLECT THE WANING OF THE SHOWERS AND
THUNDERSTORMS ACROSS OUR SOUTH. ALSO FINE TUNED THE NEAR TERM T/TD
GRIDS IN LINE WITH THE OBS AND TRENDS. UPDATES HAVE BEEN SENT TO THE
NDFD AND WEB SERVERS. A FRESHENED SET OF ZONES WILL FOLLOW.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 440 AM EDT SUN SEP 1 2013

07Z SFC ANALYSIS SHOWS AN AREA OF LOW PRESSURE MOVING INTO THE OHIO
VALLEY FROM THE CENTRAL PLAINS. THIS...IN CONJUNCTION WITH AN MCV...
CONTINUES TO DEVELOP CONVECTION OVER NORTHWESTERN/CENTRAL KENTUCKY
AND DRIFT IT SOUTHEAST INTO THE CUMBERLAND VALLEY. THE RAINS FROM
THIS COULD BE EXCESSIVE OVER PARTS OF WAYNE AND PULASKI COUNTIES
PROMPTING A CONTINUATION OF THE URBAN AND SMALL STREAM FLOOD
ADVISORIES FOR THESE LOCATIONS. IF THE RATES PICK UP IN THE NEXT
ROUND OF CONVECTION WE WILL NEED TO CONSIDER FLOOD WARNINGS...BUT SO
FAR THESE HAVE BEEN LIGHT ENOUGH TO JUST MAINTAIN THE ADVISORIES.
OTHERWISE...MOSTLY CLOUDY SKIES COVER EAST KENTUCKY KEEPING THE FOG
PATCHY AND LIGHT FOR MOST OF THE AREA. THIS IS DESPITE ANOTHER NIGHT
OF MINIMAL DEW POINT DEPRESSIONS WITH TEMPS AND DEWS HOLDING IN THE
UPPER 60S...MUCH OF THIS THE RESULT OF RAIN COOLING EARLIER IN THE
NIGHT.

THE MODELS ARE IN GOOD AGREEMENT ALOFT WITH THE NORTHWEST FLOW REGIME
OVER THE OHIO VALLEY AMPLIFYING IN RESPONSE TO A TROUGH PASSING
THROUGH THE NORTHERN GREAT LAKES TODAY THROUGH MONDAY. THIS TROUGH
WILL SEND PLENTY OF SHORTWAVE ENERGY INTO OUR AREA DURING THIS TIME
WITH THE MESOSCALE DOMINANT FOR SENSIBLE WEATHER. ACCORDINGLY...HAVE
USED THE NAM12 TO GUIDE THIS FORECAST IN COORDINATION WITH THE LATEST
HRRR AND CURRENT LARGER SCALE RADAR TRENDS.

SENSIBLE WEATHER WILL BE A CONTINUATION OF OUR WARM...HUMID...AND
STORMY HOLIDAY WEEKEND. CONVECTION IS ANTICIPATED OVER OUR SOUTHERN
AND WESTERN ZONES EARLY THIS MORNING GRADUALLY FADING OUT BEFORE
ANOTHER ROUND DEVELOPS LATER TODAY. THE STRONGEST STORMS COULD
CONTAIN GUSTY TO DAMAGING WINDS IF THEY GET TALL ENOUGH...BOW OR
MERGE. A VEERING WIND PROFILE AND SOME MID LEVEL SPEED SHEAR ALSO
SUPPORTS THIS CONCERN. OTHERWISE...THE MAIN ISSUE WILL BE EXCESSIVE
RAINFALL AND FLOODING POTENTIAL GIVEN THE RAINS THAT HAVE FALLEN AND
THE THREAT OF ADDITIONAL CONVECTION TRAINING OVER THE SAME AREAS.
CANNOT RULE OUT THE SCATTERED CONVECTION CONTINUING INTO THE NIGHT
WITH LOW PRESSURE IN PLACE OVER THE REGION AND THE APPROACH OF ITS
COLD FRONT...THOUGH THE NAM12 WOULD SUGGEST A LULL UNTIL LATER MONDAY
MORNING. HAVE RAMPED POPS DOWN DURING THIS TIME IN THE GRIDS...BUT
NOT AS MUCH AS THE NAM12 INDICATES. FOR MONDAY...THE SYSTEM/S FRONT
WILL MAKE A MORE DEFINITIVE PUSH INTO OUR AREA AND LIKELY ACTIVATE
THE REMAINING DEEP MOISTURE FOR ONE LAST GOOD ROUND OF CONVECTION
DURING THE DAY. TEMPERATURES WILL BE DEPENDENT ON CONVECTION...
PARTICULARLY FOR HIGHS TODAY AND TOMORROW...BUT IN GENERAL SHOULD BE
ABLE TO REACH THE MID AND UPPER 80S. AGAIN UPPER 60S WILL BE THE RULE
FOR LOWS TONIGHT.

USED THE CONSSHORT AND ITS BC VERSION FOR THE DEWPOINT AND WIND
GRIDS...RESPECTIVELY...THROUGH 00Z MONDAY AS A STARTING POINT AND THE
CONSALL THEREAFTER. FOR TEMPS...ADJUSTED THE CONSALL FOR SOME MINOR
TERRAIN ENHANCEMENTS IN THE LOWS TONIGHT AND PCPN CONSIDERATIONS
TODAY AND MONDAY...WITH HOURLY DIURNAL CURVE DERIVED FROM THE NAM12.
AS FOR POPS...ENDED UP CLOSER TO THE WETTER MAV GUIDANCE TODAY...
SIMILAR TO BOTH TONIGHT...AND THEN NEARER THE MET MONDAY.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 AM EDT SUN SEP 1 2013

A STRONG SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES AT THE START
OF THE PERIOD WILL PUT THE OHIO RIVER VALLEY IN A TROUGHING PATTERN.
AT THE SURFACE...AN ASSOCIATED LOW PRESSURE SYSTEM WILL GENERATE A
COLD FRONT WHICH SHOULD JUST BE EXITING EASTERN KY AT THE BEGINNING
OF THE PERIOD. THE FROPA WILL PRODUCE SHOWERS AND THUNDERSTORMS IN
THE WARM SECTOR...WHICH SHOULD BE PUSHING OUT OF THE REGION BY
TUESDAY MORNING. THE SHORTWAVE WILL CONTINUE EASTWARD THROUGHOUT THE
DAY TUESDAY...WITH HIGH PRESSURE RIDGING TAKING HOLD ACROSS KY. THIS
WILL MEAN THE RETURN OF A MUCH COOLER AND DRIER AIRMASS...WITH WINDS
AT THE MID AND UPPER LEVELS OUT OF THE NE. HIGH TEMPS WILL ONLY
REACH NEAR 80 TUESDAY.

THIS UPPER AIR PATTERN AND SURFACE HIGH PRESSURE WILL PERSIST
THROUGH THE REMAINDER OF THE WEEK...WITH ABUNDANT SUNSHINE ALLOWING
TEMPS TO RISE SLIGHTLY INTO THE LOWS 80S. WITH A DRY AIRMASS IN
PLACE...DIURNAL COOLING WILL ALLOW OVERNIGHT TEMPS TO FALL INTO THE
50S. WHILE MODELS START TO DIVERGE ON UPPER AIR SOLUTIONS BY THE END
OF THE PERIOD...THERE IS STILL SOME CONSENSUS OF ANOTHER UPPER LEVEL
SHORTWAVE DEVELOPING OVER NE CANADA FRIDAY NIGHT INTO SATURDAY. AT
THIS SURFACE THIS WILL TRANSLATE TO A LOW PRESSURE SYSTEM OVER NE
CANADA...WITH A COLD FRONT POISED TO DROP SOUTHWARD FROM THE UPPER
GREAT LAKES SATURDAY. ACCORDING THE ECWMF...WARM AIR PULLING IN
AHEAD OF THIS FRONT...COUPLED WITH DAYTIME HEATING...WILL LEAD TO
THE DEVELOPMENT OF SCT CONVECTION. HOWEVER...WILL STICK WITH A MODEL
CONSENSUS FOR SATURDAY AND SUNDAY...SINCE THIS FAR OUT THE EXACT
COURSE OF THE TROUGHING AND ASSOCIATED COLD FRONT/PRECIP IS STILL
SOMEWHAT UNKNOWN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 800 AM EDT SUN SEP 1 2013

THE LATEST ROUND OF THUNDERSTORMS HAVE TAPERED TO SHOWERS THROUGH
THE CUMBERLAND VALLEY. DO STILL EXPECT SOME ADDITIONAL STORMS TO
DEVELOP AND AFFECT THE AREA LATER IN THE DAY BUT HAVE BACKED THESE
OFF TO JUST VCTS MENTIONS GIVEN THE LATEST HRRR AND NAM12 MODEL
GUIDANCE SHOWING MORE OF A DRY PERIOD IN THE WAKE OF THE MORNING
STORMS. THE REDEVELOPMENT WILL LIKEWISE FADE OUT LATER THIS EVENING
AND PATCHY MVFR FOG CAN BE ANTICIPATED AFTER 06Z AT MOST SITES.
WINDS THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE...OUTSIDE OF ANY
STORMS.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF







AREA FORECAST DISCUSSION

NWS JACKSON KY

 345 AM EDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 240 AM EDT SUN SEP 1 2013

THE BULK OF THE CONVECTION HAS DIED OUT OVER EAST KENTUCKY...THOUGH
ADDITIONAL STORMS LOOK TO BE TRACKING INTO THE CUMBERLAND VALLEY
OVER THE NEXT SEVERAL HOURS. RAN A QUICK UPDATE MAINLY TO THE POP/WX
AND SKY GRIDS THROUGH DAWN TO REFLECT THESE CONVECTIVE...AND FOG...
TRENDS. ALSO FINE TUNED THE T AND TD GRIDS THROUGH 12Z BASED ON THE
CURRENT OBS. THE GRID UPDATES HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS.

UPDATE ISSUED AT 1043 PM EDT SAT AUG 31 2013

MADE A COUPLE OF UPDATES TO ACCOUNT FOR ONGOING CONVECTION AND ITS
EXPECTED COURSE DURING THE OVERNIGHT. LATEST HRRR SEEMS TO HAVE A
FAIRLY GOOD HANDLE ON THE SITUATION...WITH THE BEST
CONVECTION/THUNDERSTORMS TO OUR WEST CONTINUING TO DIVE MORE
SOUTHWARD...ONLY INFLUENCING OUR SOUTHWESTERN COUNTIES. UNFORTUNATELY
THIS AREA HAS ALREADY BEEN IMPACTED WITH HEAVY RAINS AND
THUNDERSTORMS EARLIER IN THE EVENING...SO THE BIGGEST CONCERN IS THE
POTENTIAL FOR MORE FLASH FLOODING WITH ANY HEAVY SHOWER OR
THUNDERSTORM THAT PASSES OVER. THE ENTIRE WESTERN HALF OF THE CWA CAN
STILL EXPECT SOME RAINFALL AND SCT THUNDERSTORMS THROUGHOUT THE NEXT
FEW HOURS AS WELL. A MAJORITY OF THE CONVECTION IS PROJECTED TO
DISSIPATE LATE TONIGHT...SO DID NOT MAKE ANY CHANGES PAST THIS
PERIOD.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 420 PM EDT SAT AUG 31 2013

THE MAIN CLUSTER OF CONVECTION CONTINUES TO SLOWLY MOVE SOUTH ACROSS
PORTIONS OF EASTERN KENTUCKY. THIS CLUSTER WAS MORE ORGANIZED WHEN IT
WAS MOVING THROUGH THE I-64 CORRIDOR AND HAS SINCE BECOME MORE
CELLULAR. HEAVY RAINFALL IS THE MAIN CONCERN WITH THESE...HOWEVER
GIVEN THAT THE OUTFLOW HAS ALREADY SURGED SOUTH AWAY FROM THE
ACTIVITY...WOULD EXPECT THE STORMS TO CONTINUE TO GRADUALLY WEAKEN
WITH TIME.

ANOTHER MORE ORGANIZED AREA OF CONVECTION IS ALIGNED ACROSS NORTH
CENTRAL KENTUCKY ASSOCIATED MORE WITH A SUBTLE OUTFLOW BOUNDARY FROM
CONVECTION THAT HAD OCCURRED LAST NIGHT. THE LATEST HRRR HAS BEEN
KEEPING THIS CONVECTION MORE CONFINED TO SOUTHERN KENTUCKY WITH
TIME...ALTHOUGH IT IS NOT MAKING MUCH OF A TURN YET. CVG DOWN TO LEX
HAS RECOVERED WELL FROM EARLIER CLOUD COVER...HOWEVER THE AIR CLOSER
TOWARDS OUR BLUEGRASS COUNTIES IS NOT AS UNSTABLE. THE BEST
INSTABILITY REMAINS ACROSS OUR SOUTHWEST COUNTIES...WITH
TEMPERATURES IN THE UPPER 80S AND DEW POINTS IN THE UPPER 60S TO
LOWER 70S. THERE IS ALSO AN OUTFLOW BOUNDARY THAT APPEARS TO HAVE
STALLED FROM ALONG A MOUNT VERNON TO HARLAN LINE...WHICH MAY SERVE AS
A FOCUS FOR DEVELOPMENT THROUGH EARLY THIS EVENING. AS SUCH...WILL
HAVE SOME HIGHER POPS IN THE SOUTHWEST...WITH LOWER POPS IN THE
NORTHEAST WHERE CONVECTION HAS WORKED OVER THE AIR MASS.

WEAK SHORT WAVE TROUGHS WILL CONTINUE TO TRAVERSE THE OHIO VALLEY
THROUGH THE REST OF THE SHORT TERM...HOWEVER AS PREVIOUSLY STATED IN
EARLIER DISCUSSIONS...THE MESOSCALE WILL CONTINUE TO DRIVE THE
WEATHER. AS SUCH...HAVE STUCK WITH CONTINUITY...AND ALLOWED FOR A
GENERAL DIURNAL INCREASE IN CONVECTION THROUGH THE DAY ON SUNDAY...
HOWEVER COULD NOT DROP OFF THE POPS TOO MUCH AT NIGHT.

HEAVY RAINFALL WILL BE THE MAIN HAZARD THROUGH THE SHORT TERM...AND
WILL MENTION THE POTENTIAL FOR ISOLATED FLASH FLOODING NOW THAT SOME
LOCATIONS HAVE BEEN PRIMED. A FEW STRONGER STORMS COULD ALSO PRODUCE
SOME STRONG WIND GUSTS AND POSSIBLY SMALL HAIL AS WELL.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 AM EDT SUN SEP 1 2013

A STRONG SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES AT THE START
OF THE PERIOD WILL PUT THE OHIO RIVER VALLEY IN A TROUGHING PATTERN.
AT THE SURFACE...AN ASSOCIATED LOW PRESSURE SYSTEM WILL GENERATE A
COLD FRONT WHICH SHOULD JUST BE EXITING EASTERN KY AT THE BEGINNING
OF THE PERIOD. THE FROPA WILL PRODUCE SHOWERS AND THUNDERSTORMS IN
THE WARM SECTOR...WHICH SHOULD BE PUSHING OUT OF THE REGION BY
TUESDAY MORNING. THE SHORTWAVE WILL CONTINUE EASTWARD THROUGHOUT THE
DAY TUESDAY...WITH HIGH PRESSURE RIDGING TAKING HOLD ACROSS KY. THIS
WILL MEAN THE RETURN OF A MUCH COOLER AND DRIER AIRMASS...WITH WINDS
AT THE MID AND UPPER LEVELS OUT OF THE NE. HIGH TEMPS WILL ONLY
REACH NEAR 80 TUESDAY.

THIS UPPER AIR PATTERN AND SURFACE HIGH PRESSURE WILL PERSIST
THROUGH THE REMAINDER OF THE WEEK...WITH ABUNDANT SUNSHINE ALLOWING
TEMPS TO RISE SLIGHTLY INTO THE LOWS 80S. WITH A DRY AIRMASS IN
PLACE...DIURNAL COOLING WILL ALLOW OVERNIGHT TEMPS TO FALL INTO THE
50S. WHILE MODELS START TO DIVERGE ON UPPER AIR SOLUTIONS BY THE END
OF THE PERIOD...THERE IS STILL SOME CONSENSUS OF ANOTHER UPPER LEVEL
SHORTWAVE DEVELOPING OVER NE CANADA FRIDAY NIGHT INTO SATURDAY. AT
THIS SURFACE THIS WILL TRANSLATE TO A LOW PRESSURE SYSTEM OVER NE
CANADA...WITH A COLD FRONT POISED TO DROP SOUTHWARD FROM THE UPPER
GREAT LAKES SATURDAY. ACCORDING THE ECWMF...WARM AIR PULLING IN
AHEAD OF THIS FRONT...COUPLED WITH DAYTIME HEATING...WILL LEAD TO
THE DEVELOPMENT OF SCT CONVECTION. HOWEVER...WILL STICK WITH A MODEL
CONSENSUS FOR SATURDAY AND SUNDAY...SINCE THIS FAR OUT THE EXACT
COURSE OF THE TROUGHING AND ASSOCIATED COLD FRONT/PRECIP IS STILL
SOMEWHAT UNKNOWN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 300 AM EDT SUN SEP 1 2013

THUNDERSTORMS HAVE TAPERED TO SHOWERS THROUGH MOST OF THE AREA...BUT
AN ADDITIONAL ROUND OF STORMS MAY AFFECT SME AND LOZ FROM NOW UNTIL
12Z. OUTSIDE OF THE CUMBERLAND VALLEY...PATCHY FOG WILL BE THE MAIN
AVN CONCERN INTO DAWN. DO EXPECT ADDITIONAL STORMS TO DEVELOP AND
AFFECT THE ENTIRE AREA LATER ON SUNDAY WITH A PEAK OF COVERAGE
ANTICIPATED DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. HAVE
REFLECTED THIS IN THE TAFS VIA A PREVAILING SHRA AND VCTS DURING THIS
TIME. LATE ON...BACKED THESE OFF TO JUST VCSH MENTIONS AFTER 02Z AS
INSTABILITY WANES. WINDS THROUGH THE PERIOD WILL BE LIGHT AND
VARIABLE...OUTSIDE OF ANY STORMS.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...JMW
AVIATION...GREIF







AREA FORECAST DISCUSSION...UPDATED

NWS JACKSON KY

 300 AM EDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 240 AM EDT SUN SEP 1 2013

THE BULK OF THE CONVECTION HAS DIED OUT OVER EAST KENTUCKY...THOUGH
ADDITIONAL STORMS LOOK TO BE TRACKING INTO THE CUMBERLAND VALLEY
OVER THE NEXT SEVERAL HOURS. RAN A QUICK UPDATE MAINLY TO THE POP/WX
AND SKY GRIDS THROUGH DAWN TO REFLECT THESE CONVECTIVE...AND FOG...
TRENDS. ALSO FINE TUNED THE T AND TD GRIDS THROUGH 12Z BASED ON THE
CURRENT OBS. THE GRID UPDATES HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS.

UPDATE ISSUED AT 1043 PM EDT SAT AUG 31 2013

MADE A COUPLE OF UPDATES TO ACCOUNT FOR ONGOING CONVECTION AND ITS
EXPECTED COURSE DURING THE OVERNIGHT. LATEST HRRR SEEMS TO HAVE A
FAIRLY GOOD HANDLE ON THE SITUATION...WITH THE BEST
CONVECTION/THUNDERSTORMS TO OUR WEST CONTINUING TO DIVE MORE
SOUTHWARD...ONLY INFLUENCING OUR SOUTHWESTERN COUNTIES. UNFORTUNATELY
THIS AREA HAS ALREADY BEEN IMPACTED WITH HEAVY RAINS AND
THUNDERSTORMS EARLIER IN THE EVENING...SO THE BIGGEST CONCERN IS THE
POTENTIAL FOR MORE FLASH FLOODING WITH ANY HEAVY SHOWER OR
THUNDERSTORM THAT PASSES OVER. THE ENTIRE WESTERN HALF OF THE CWA CAN
STILL EXPECT SOME RAINFALL AND SCT THUNDERSTORMS THROUGHOUT THE NEXT
FEW HOURS AS WELL. A MAJORITY OF THE CONVECTION IS PROJECTED TO
DISSIPATE LATE TONIGHT...SO DID NOT MAKE ANY CHANGES PAST THIS
PERIOD.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 420 PM EDT SAT AUG 31 2013

THE MAIN CLUSTER OF CONVECTION CONTINUES TO SLOWLY MOVE SOUTH ACROSS
PORTIONS OF EASTERN KENTUCKY. THIS CLUSTER WAS MORE ORGANIZED WHEN IT
WAS MOVING THROUGH THE I-64 CORRIDOR AND HAS SINCE BECOME MORE
CELLULAR. HEAVY RAINFALL IS THE MAIN CONCERN WITH THESE...HOWEVER
GIVEN THAT THE OUTFLOW HAS ALREADY SURGED SOUTH AWAY FROM THE
ACTIVITY...WOULD EXPECT THE STORMS TO CONTINUE TO GRADUALLY WEAKEN
WITH TIME.

ANOTHER MORE ORGANIZED AREA OF CONVECTION IS ALIGNED ACROSS NORTH
CENTRAL KENTUCKY ASSOCIATED MORE WITH A SUBTLE OUTFLOW BOUNDARY FROM
CONVECTION THAT HAD OCCURRED LAST NIGHT. THE LATEST HRRR HAS BEEN
KEEPING THIS CONVECTION MORE CONFINED TO SOUTHERN KENTUCKY WITH
TIME...ALTHOUGH IT IS NOT MAKING MUCH OF A TURN YET. CVG DOWN TO LEX
HAS RECOVERED WELL FROM EARLIER CLOUD COVER...HOWEVER THE AIR CLOSER
TOWARDS OUR BLUEGRASS COUNTIES IS NOT AS UNSTABLE. THE BEST
INSTABILITY REMAINS ACROSS OUR SOUTHWEST COUNTIES...WITH
TEMPERATURES IN THE UPPER 80S AND DEW POINTS IN THE UPPER 60S TO
LOWER 70S. THERE IS ALSO AN OUTFLOW BOUNDARY THAT APPEARS TO HAVE
STALLED FROM ALONG A MOUNT VERNON TO HARLAN LINE...WHICH MAY SERVE AS
A FOCUS FOR DEVELOPMENT THROUGH EARLY THIS EVENING. AS SUCH...WILL
HAVE SOME HIGHER POPS IN THE SOUTHWEST...WITH LOWER POPS IN THE
NORTHEAST WHERE CONVECTION HAS WORKED OVER THE AIR MASS.

WEAK SHORT WAVE TROUGHS WILL CONTINUE TO TRAVERSE THE OHIO VALLEY
THROUGH THE REST OF THE SHORT TERM...HOWEVER AS PREVIOUSLY STATED IN
EARLIER DISCUSSIONS...THE MESOSCALE WILL CONTINUE TO DRIVE THE
WEATHER. AS SUCH...HAVE STUCK WITH CONTINUITY...AND ALLOWED FOR A
GENERAL DIURNAL INCREASE IN CONVECTION THROUGH THE DAY ON SUNDAY...
HOWEVER COULD NOT DROP OFF THE POPS TOO MUCH AT NIGHT.

HEAVY RAINFALL WILL BE THE MAIN HAZARD THROUGH THE SHORT TERM...AND
WILL MENTION THE POTENTIAL FOR ISOLATED FLASH FLOODING NOW THAT SOME
LOCATIONS HAVE BEEN PRIMED. A FEW STRONGER STORMS COULD ALSO PRODUCE
SOME STRONG WIND GUSTS AND POSSIBLY SMALL HAIL AS WELL.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 437 PM EDT SAT AUG 31 2013

THE PREDOMINANT PATTERN DURING THE PERIOD WILL FEATURE A LARGE UPPER
LEVEL RIDGE CENTERED NEAR COLORADO...AND A BROAD TROUGH OVER THE
EASTERN CONUS WITH IMPULSES PASSING THROUGH IT. THIS RESULTS IN
GENERAL NW FLOW ALOFT FOR OUR AREA...WITH THE UPPER LEVEL IMPULSES
BRINGING SURFACE COLD FRONTS SOUTH AND SOUTHEAST. ONE OF THESE
IMPULSES AND FRONTS IS SLATED TO AFFECT US AT THE START OF THE
PERIOD...WITH FROPA ON MONDAY NIGHT. WITH GENERAL MODEL AGREEMENT ON
THIS...AND THE FRONT APPROACHING AT PEAK HEATING...HAVE USED LIKELY
POPS DURING THE DAY. WITH THE COLD FRONT EXPECTED TO PASS ON MONDAY
EVENING AND A LOSS OF HEATING...POPS DROP OFF FOR THE NIGHT. SURFACE
HIGH PRESSURE THEN BUILDS IN WITH A DRIER AIR MASS FOR TUESDAY.

ANOTHER COLD FRONT DROPS IN ON THURSDAY...BUT POOR MOISTURE RETURN
IS ANTICIPATED BEFORE FROPA...AND WILL GO WITH A DRY FORECAST.
ANOTHER COLD FRONT APPROACHES ON SATURDAY...BUT MODELS ARE NOT
CONSISTENT ON ITS STRENGTH OR TIMING. NONE OF THE MODELS SEEM TO
SHOW GOOD MOISTURE RETURN AT THIS POINT...AND HAVE LEFT THE FORECAST
DRY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 300 AM EDT SUN SEP 1 2013

THUNDERSTORMS HAVE TAPERED TO SHOWERS THROUGH MOST OF THE AREA...BUT
AN ADDITIONAL ROUND OF STORMS MAY AFFECT SME AND LOZ FROM NOW UNTIL
12Z. OUTSIDE OF THE CUMBERLAND VALLEY...PATCHY FOG WILL BE THE MAIN
AVN CONCERN INTO DAWN. DO EXPECT ADDITIONAL STORMS TO DEVELOP AND
AFFECT THE ENTIRE AREA LATER ON SUNDAY WITH A PEAK OF COVERAGE
ANTICIPATED DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. HAVE
REFLECTED THIS IN THE TAFS VIA A PREVAILING SHRA AND VCTS DURING THIS
TIME. LATE ON...BACKED THESE OFF TO JUST VCSH MENTIONS AFTER 02Z AS
INSTABILITY WANES. WINDS THROUGH THE PERIOD WILL BE LIGHT AND
VARIABLE...OUTSIDE OF ANY STORMS.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...HAL
AVIATION...GREIF






AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 146 PM EDT SUN SEP 1 2013

.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL PERSIST OVER THE AREA THROUGH
TONIGHT...AS HIGH PRESSURE REMAINS WELL OFF THE COAST. A COLD
FRONT WILL APPROACH THE REGION FROM THE WEST ON MONDAY...AND WILL
PUSH ACROSS THE AREA TUESDAY MORNING. HIGH PRESSURE WILL BUILD
OVER THE MID ATLANTIC STATES LATE TUESDAY AND WEDNESDAY...BRINGING
COOLER AND LESS HUMID CONDITIONS TO THE AREA BY MIDWEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
1 PM UPDATE...A SMALL CONVECTIVE VORT MAX APPEARS ON STLT TO BE
MOVING ACROSS THE LOWER EASTERN SHORE. THIS MAY TRIGGER A FEW
SHOWERS OR TSTMS THROUGH 18Z NEAR THE MD COAST WITH 30 POP THROUGH
18Z THEN 20 POP REST THE AFTN. A SIGNIFICANT CU FIELD HAS DEVELOPED
ACRS NE NORTH CAROLINA AND EXTREME SOUTHEAST VIRGINIA IN THE SAME
AREA THAT HRRR AND ARW HAVE TSTMS DEVELOP EARLY THIS AFTN, HAVE
PLACED 30 PERCENT POPS FOR THE AFTN ACROSS A LARGE PART OF
SOUTHEAST VIRGINIA AND OUR NORTHEAST NORTH CAROLINA COUNTIES.

TEMPERATURES ARE RUNNING A BIT COOLER THAN EXPECTED OVER THE
PIEDMONT AREA AND CU FIELD HAD NOT BEGUN TO FORM AS OF 16Z. .
LOWERED MAX TEMPERATURES 1 TO 2 DEGREES AND LOWERED POPS TO 20
PERCENT THROUGH 20Z.

PREVIOUS DISCUSSION...
THE MAIN SHORT WAVE THAT WILL IMPACT THE AREA TOWARD EVENING WAS
PUSHING INTO EXTREME SOUTHWEST VIRGINIA AS OF 16Z. SIMILAR TO
SATURDAY...LEESIDE TROUGH WILL DEVELOP AS THE SHORT WAVE MOVES IN
FROM THE WEST, EXPECT TSTMS TO DEVELOP NEAR THE BLUE RIDGE WITH
CONVECTION SPREADING TO THE EAST TOWARD EVENING. CONTINUED WITH
POPS 30-40 PERCENT W OF INTERSTATE 95 DECREASING TOWARD THE COAST.
HIGH TEMPERATURES RANGE FROM THE UPR 80S TO AROUND 90 ACROSS MOST
AREAS,

PRECIPITIBLE WATER OF AROUND AN INCH AND THREE QUARTERS AND WEAK
STEERING CURRENTS MAY RESULT IN LOCALLY HEAVY RAINFALL AND MINOR
FLOODING. SOME TSTMS MAY PRODUCE GUSTY WINDS IN THE RANGE OF 30 TO
40 MPH. DUE TO RELATIVELY WEAK SHEAR...TSTMS SHOULD REMAIN
SCATTERED. AFT 00Z...SHOWERS AND SCATTERED TSTMS WILL LINGER INTO
THE EVENING AS THE SHORT WAVE MOVES ACRS NRN PORTIONS OF THE AREA.
KEPT POPS OF 30 TO 40 PERCENT N OF INTERSTATE 64 AND ACROSS THE
LOWER EASTERN SHORE THROUGH MIDNIGHT, BY MORNING...LOW TEMPERATURES
RANGE FROM 70 TO 75.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
INCREMENTAL INCREASE IN POPS CONTINUES ON MONDAY, AS UPPER TROUGH
PERSISTS AND SFC FRONT SLOWLY APPROACHES FROM THE W-NW. ONCE AGAIN
EXPECT SHOWERS TO FIRE UPSTREAM AND FILL IN ALONG PRE-FRONTAL
TROUGH, THOUGH DEVELOPING DOWNSLOPE FLOW AND CONTINUED ANEMIC DEEP
LAYER SHEAR VALUES WOULD ARGUE FOR WEAKER/LESS ORGANIZED CELLS.
EITHER WAY, DEEPER MOISTURE AND STRONGER DYNAMICS SUPPORT
INCREASED CHC FOR SHOWERS AND TSTMS BY LABOR DAY
AFTN/EVENING...AND WILL CARRY 50% POPS DURING THIS PERIOD.

TEMPERATURES ARE A BIT OF A CHALLENGE CONSIDERING INCREASING AFTN
CLOUDS AND RATHER STARK DIFFERENCE IN NUMERICAL GUIDANCE. ATTM,
THINKING IS THAT MAV (GFS) GUIDANCE IS TOO HIGH...AS IT HAS BEEN
NUMEROUS TIMES IN SIMILAR PRE-FRONTAL SITUATIONS. INCREASING
CLOUDS/AFTN PCPN SHOULD KEEP MAXIMA BELOW THESE VALUES, AND CLOSER
TO COOLER MET NUMBERS. DID ADJUST TEMPS UPWARD SLIGHTLY GIVEN
SLOWER FRONTAL TIMING...WITH HIGHS MONDAY GENERALLY IN THE LOWER
90S (MID-UPPER 80S ALONG IMMEDIATE COASTAL AREAS). WARM AND MUGGY
ONCE AGAIN MONDAY NIGHT, WITH EARLY MORNING LOWS IN THE LOWER TO
MIDDLE 70S.

TUESDAY...
HAVE GONE CLOSEST TO THE ECMWF SOLUTION FOR FRONTAL TIMING, WHICH
IS A GENERAL CONSENSUS OF THE MORE PROGRESSIVE 00Z GFS AND SLOWER
NAM SOLUTION. EXPECT THE FRONT TO BE ORIENTED FROM THE MD ERN
SHORE SW THROUGH SOUTH CENTRAL VA AT 12Z/8A TUE, WITH THE FRONT
SLOWLY SLIDING SE OFF THE COAST BY TUE EVENING (00Z WED/8PM TUES
NGT). UPPER JET LINGERS ALONG THE COAST HOWEVER, AND WITH UPPER
TROUGH AXIS PIVOTING OFFSHORE DURING THIS PERIOD, EXPECT THAT AT
LEAST SCATTERED SHRAS/TSTMS WL CONTINUE ACRS SE HALF OF THE AREA
THROUGH TUE AFTN...WITH LESS COVERAGE FARTHER N/W AS COOLER/DRIER
AIRMASS OF CANADIAN ORIGIN FILTERS IN FROM THE NW. HIGHS TUE WILL
AVG IN THE MID-UPPER 80S UNDER A PARTLY TO MOSTLY CLOUDY SKY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LARGE SCALE PATTERN DURING THE MEDIUM RANGE PERIOD CHARACTERIZED BY
STRONG MID LVL RIDGE OVER THE ROCKIES AND A MID LEVEL TROUGH OVER
THE EASTERN CONUS. HIGH PRESSURE BUILDS IN FROM THE NW TUE NIGHT-WED
IN THE WAKE OF SFC FROPA...AND PERSISTS OVER THE REGION INTO THU
AS THE DEEP UPPER TROUGH BECOMES ANCHORED OVER EASTERN CANADA.
EXPECT COOLER AND DRIER/MORE COMFORTABLE CONDITIONS WED WITH HIGHS
MAINLY 80-85. FLOW BRIEFLY TURNS BACK TO THE SW ON THU ALLOWING FOR
SOMEWHAT WARMER TEMPS INTO THE MIDDLE 80S AHEAD OF THE NEXT FRONT.
THIS FRONT LOOKS TO COME THROUGH THU NIGHT/EARLY FRI WITH MINIMAL
DYNAMICS SO WILL KEEP FORECAST DRY WITH JUST SOME INCREASE IN
CLOUDS. PARTLY TO MOSTLY SUNNY FRI W/ HIGHS 80-84. MOISTURE MAY
START TO INCREASE AGAIN NEXT WEEKEND FOR SLIGHT CHC POPS.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NUMEROUS SHOWERS WITH EMBEDDED TSTRMS QUICKLY DVLPNG AS WEAK S/W
MOVES CROSS THE DELMARVA ALONG WITH A SFC TROF EXTENDING SW ACROSS
SERN VA / NC. THUS...HAVE INCLUDED VCSH ACROSS COASTAL TAF SITES
NEXT SEVRAL HRS. ADDITIONAL CONVECTION EXPECTED TO DVLP ACROSS THE
MTS THEN MOVE SE LATER THIS AFTRN. TIMING OF ANY CONVECTION AT RIC
PROBLEMATIC ATTM SO KEPT THEM DRY FOR NOW.

CONVECTION EXPECTED TO DISSIPATE AFTER SUNSET WITH VFR CONDITIONS
THROUGH THE NIGHT. HOWEVER...MODELS HINTING THAT SOME LATE NIGHT
FOG DEVELOPING...ESPECIALLY WHERE IT DOES RAIN. SO ADDED SOME MVFR
VSBYS FOR BR OVER INLAND TAF SITES.

ANOTHER ROUND OF SHOWERS / TSTRMS EXPECTED MONDAY AHEAD OF A COLD
FRONT THAT WILL BRING IN A LESS HUID AIRMASS INTO THE REGION BY
MID WEEK.

&&

.MARINE...
SURFACE AND MID LEVEL TROUGHING WILL RESIDE OVER THE REGION TODAY.
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE
INLAND TROUGH AND ARE EXPECTED TO MOVE OVER THE WATERS MAINLY THIS
EVENING...AND AFTER MIDNIGHT BECOMING MORE FOCUSED OVER NRN CHES
BAY/NRN COASTAL WATERS. S-SW WINDS OVER ALL WATERS WILL AVERAGE
10-15 KT TODAY AND TONIGHT...AND WAVES/SEAS WILL AVERAGE 1-3 FT
(POSSIBLY UP TO 4 FT OUT NEAR 20 NM EARLY MONDAY MORNING).

A MORE SUBSTANTIAL SURFACE COLD FRONT APPROACHES FROM THE WEST ON
MONDAY. THIS WILL RESULT IN INCREASING SHOWER/THUNDERSTORM ACTIVITY
BY MONDAY EVENING AS THE FRONT BEGINS TO PUSH OVER THE WATERS. THE
FRONT SLOWLY PUSHES ACROSS THE WATERS ON TUESDAY AND STALLS ALONG
THE COAST TUESDAY NIGHT. SHOWER/STORMS WILL ALSO BE POSSIBLE ON
TUESDAY...ESPECIALLY ALONG THE FRONTAL BOUNDARY. BREEZY S-SW WINDS
MONDAY AND TUESDAY WILL AVERAGE 10-15 KT (UP TO 20 KT AT TIMES FOR
COASTAL WATERS)...THEN FINALLY VEER TO THE W-NW BEHIND THE FRONT
TUESDAY NIGHT. A COOL NW-N SURGE TUESDAY NIGHT INTO WEDNESDAY
MORNING MAY RESULT IN A PERIOD OF SCA HEADLINES...ALTHOUGH TIMING ON
THIS REMAINS UNCERTAIN. HIGH PRESSURE RE-ESTABLISHES ITSELF OVER THE
MID ATLANTIC STATES FROM WEDNESDAY THROUGH AT LEAST SATURDAY.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MAM
NEAR TERM...LSA
SHORT TERM...LKB/MAM
LONG TERM...JDM
AVIATION...MPR
MARINE...BMD







AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 1256 PM EDT SUN SEP 1 2013

.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL PERSIST OVER THE AREA THROUGH
TONIGHT...AS HIGH PRESSURE REMAINS WELL OFF THE COAST. A COLD
FRONT WILL APPROACH THE REGION FROM THE WEST ON MONDAY...AND WILL
PUSH ACROSS THE AREA TUESDAY MORNING. HIGH PRESSURE WILL BUILD
OVER THE MID ATLANTIC STATES LATE TUESDAY AND WEDNESDAY...BRINGING
COOLER AND LESS HUMID CONDITIONS TO THE AREA BY MIDWEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
1 PM UPDATE...A SMALL CONVECTIVE VORT MAX APPEARS ON STLT TO BE
MOVING ACROSS THE LOWER EASTERN SHORE. THIS MAY TRIGGER A FEW
SHOWERS OR TSTMS THROUGH 18Z NEAR THE MD COAST WITH 30 POP THROUGH
18Z THEN 20 POP REST THE AFTN. A SIGNIFICANT CU FIELD HAS DEVELOPED
ACRS NE NORTH CAROLINA AND EXTREME SOUTHEAST VIRGINIA IN THE SAME
AREA THAT HRRR AND ARW HAVE TSTMS DEVELOP EARLY THIS AFTN, HAVE
PLACED 30 PERCENT POPS FOR THE AFTN ACROSS A LARGE PART OF
SOUTHEAST VIRGINIA AND OUR NORTHEAST NORTH CAROLINA COUNTIES.

TEMPERATURES ARE RUNNING A BIT COOLER THAN EXPECTED OVER THE
PIEDMONT AREA AND CU FIELD HAD NOT BEGUN TO FORM AS OF 16Z. .
LOWERED MAX TEMPERATURES 1 TO 2 DEGREES AND LOWERED POPS TO 20
PERCENT THROUGH 20Z.

PREVIOUS DISCUSSION...
THE MAIN SHORT WAVE THAT WILL IMPACT THE AREA TOWARD EVENING WAS
PUSHING INTO EXTREME SOUTHWEST VIRGINIA AS OF 16Z. SIMILAR TO
SATURDAY...LEESIDE TROUGH WILL DEVELOP AS THE SHORT WAVE MOVES IN
FROM THE WEST, EXPECT TSTMS TO DEVELOP NEAR THE BLUE RIDGE WITH
CONVECTION SPREADING TO THE EAST TOWARD EVENING. CONTINUED WITH
POPS 30-40 PERCENT W OF INTERSTATE 95 DECREASING TOWARD THE COAST.
HIGH TEMPERATURES RANGE FROM THE UPR 80S TO AROUND 90 ACROSS MOST
AREAS,

PRECIPITIBLE WATER OF AROUND AN INCH AND THREE QUARTERS AND WEAK
STEERING CURRENTS MAY RESULT IN LOCALLY HEAVY RAINFALL AND MINOR
FLOODING. SOME TSTMS MAY PRODUCE GUSTY WINDS IN THE RANGE OF 30 TO
40 MPH. DUE TO RELATIVELY WEAK SHEAR...TSTMS SHOULD REMAIN
SCATTERED. AFT 00Z...SHOWERS AND SCATTERED TSTMS WILL LINGER INTO
THE EVENING AS THE SHORT WAVE MOVES ACRS NRN PORTIONS OF THE AREA.
KEPT POPS OF 30 TO 40 PERCENT N OF INTERSTATE 64 AND ACROSS THE
LOWER EASTERN SHORE THROUGH MIDNIGHT, BY MORNING...LOW TEMPERATURES
RANGE FROM 70 TO 75.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
INCREMENTAL INCREASE IN POPS CONTINUES ON MONDAY, AS UPPER TROUGH
PERSISTS AND SFC FRONT SLOWLY APPROACHES FROM THE W-NW. ONCE AGAIN
EXPECT SHOWERS TO FIRE UPSTREAM AND FILL IN ALONG PRE-FRONTAL
TROUGH, THOUGH DEVELOPING DOWNSLOPE FLOW AND CONTINUED ANEMIC DEEP
LAYER SHEAR VALUES WOULD ARGUE FOR WEAKER/LESS ORGANIZED CELLS.
EITHER WAY, DEEPER MOISTURE AND STRONGER DYNAMICS SUPPORT
INCREASED CHC FOR SHOWERS AND TSTMS BY LABOR DAY
AFTN/EVENING...AND WILL CARRY 50% POPS DURING THIS PERIOD.

TEMPERATURES ARE A BIT OF A CHALLENGE CONSIDERING INCREASING AFTN
CLOUDS AND RATHER STARK DIFFERENCE IN NUMERICAL GUIDANCE. ATTM,
THINKING IS THAT MAV (GFS) GUIDANCE IS TOO HIGH...AS IT HAS BEEN
NUMEROUS TIMES IN SIMILAR PRE-FRONTAL SITUATIONS. INCREASING
CLOUDS/AFTN PCPN SHOULD KEEP MAXIMA BELOW THESE VALUES, AND CLOSER
TO COOLER MET NUMBERS. DID ADJUST TEMPS UPWARD SLIGHTLY GIVEN
SLOWER FRONTAL TIMING...WITH HIGHS MONDAY GENERALLY IN THE LOWER
90S (MID-UPPER 80S ALONG IMMEDIATE COASTAL AREAS). WARM AND MUGGY
ONCE AGAIN MONDAY NIGHT, WITH EARLY MORNING LOWS IN THE LOWER TO
MIDDLE 70S.

TUESDAY...
HAVE GONE CLOSEST TO THE ECMWF SOLUTION FOR FRONTAL TIMING, WHICH
IS A GENERAL CONSENSUS OF THE MORE PROGRESSIVE 00Z GFS AND SLOWER
NAM SOLUTION. EXPECT THE FRONT TO BE ORIENTED FROM THE MD ERN
SHORE SW THROUGH SOUTH CENTRAL VA AT 12Z/8A TUE, WITH THE FRONT
SLOWLY SLIDING SE OFF THE COAST BY TUE EVENING (00Z WED/8PM TUES
NGT). UPPER JET LINGERS ALONG THE COAST HOWEVER, AND WITH UPPER
TROUGH AXIS PIVOTING OFFSHORE DURING THIS PERIOD, EXPECT THAT AT
LEAST SCATTERED SHRAS/TSTMS WL CONTINUE ACRS SE HALF OF THE AREA
THROUGH TUE AFTN...WITH LESS COVERAGE FARTHER N/W AS COOLER/DRIER
AIRMASS OF CANADIAN ORIGIN FILTERS IN FROM THE NW. HIGHS TUE WILL
AVG IN THE MID-UPPER 80S UNDER A PARTLY TO MOSTLY CLOUDY SKY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
LARGE SCALE PATTERN DURING THE MEDIUM RANGE PERIOD CHARACTERIZED BY
STRONG MID LVL RIDGE OVER THE ROCKIES AND A MID LEVEL TROUGH OVER
THE EASTERN CONUS. HIGH PRESSURE BUILDS IN FROM THE NW TUE NIGHT-WED
IN THE WAKE OF SFC FROPA...AND PERSISTS OVER THE REGION INTO THU
AS THE DEEP UPPER TROUGH BECOMES ANCHORED OVER EASTERN CANADA.
EXPECT COOLER AND DRIER/MORE COMFORTABLE CONDITIONS WED WITH HIGHS
MAINLY 80-85. FLOW BRIEFLY TURNS BACK TO THE SW ON THU ALLOWING FOR
SOMEWHAT WARMER TEMPS INTO THE MIDDLE 80S AHEAD OF THE NEXT FRONT.
THIS FRONT LOOKS TO COME THROUGH THU NIGHT/EARLY FRI WITH MINIMAL
DYNAMICS SO WILL KEEP FORECAST DRY WITH JUST SOME INCREASE IN
CLOUDS. PARTLY TO MOSTLY SUNNY FRI W/ HIGHS 80-84. MOISTURE MAY
START TO INCREASE AGAIN NEXT WEEKEND FOR SLIGHT CHC POPS.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
SURFACE TO MID LEVEL TROUGHING RESIDES OVER THE MID ATLANTIC REGION
EARLY THIS MORNING AND IS EXPECTED TO REMAIN STEADFAST THROUGH TODAY.
THERE ARE PLENTY OF HIGH DEBRIS CLOUDS AND FEW-SCT MID LEVEL CU LEFT
FROM SHOWERS ON SATURDAY EVENING. VERY DIFFUSE DRY SLOTTING CAN BE
SEEN IN WATER VAPOR IMAGERY AND MAY LEAD TO SOME THINNING OF THE
BKN-OVC CIRRUS THROUGH THE MORNING. HOWEVER ONCE DAYTIME HEATING
BEGINS...EXPECT MORE CU DEVELOPMENT TO OCCUR FROM LATE MORNING INTO
THE AFTERNOON.

MEANWHILE...SHORTWAVE ENERGY FROM THE OHIO VALLEY WILL SLIDE CLOSER
TO THE APPALACHIANS AND INTERACT WITH THE TROUGHING CURRENTLY IN
PLACE. THIS WILL PROMOTE SHOWER/THUNDERSTORM DEVELOPMENT LATE THIS
AFTERNOON INTO THE EVENING...AND SHOULD RESULT IN PRECIPITATION
SHIFTING FARTHER EAST THAN THE DAY BEFORE. SHOWERS/STORMS MAY HAVE A
TOUGH TIME REACHING ALL THE WAY TO THE COAST DUE TO THE LOSS OF
DAYTIME HEATING BY THE TIME THE MOISTURE ARRIVES AND ALSO DUE TO
POSSIBLE DRY SLOTTING. KRIC AND KSBY HAVE THE BEST CHANCE OF
EXPERIENCING THUNDERSTORMS TODAY INTO TONIGHT...WHILE KPHF/KORF/KECG
MAY SEE A SHOWER OR TWO BUT THAT SHOULD BE IT. SHOWERS AND STORMS
SHOULD TAPER OFF QUICKLY AFTER MIDNIGHT...WITH LINGERING SHOWERS
POSSIBLE OVERNIGHT IN AREAS NE OF INTERSTATE 64 (INCLUDING THE MD/VA
EASTERN SHORE). SOUTH WINDS WILL BECOME BREEZY BY MID TO LATE
MORNING AS THE PRESSURE GRADIENT TIGHTENS UP AGAIN THROUGH THE
AFTERNOON.

A MORE SUBSTANTIAL SURFACE COLD FRONT APPROACHES FROM THE WEST ON
MONDAY. THIS WILL RESULT IN INCREASED SHOWER/THUNDERSTORM CHANCES
AND COVERAGE BY MONDAY EVENING AS THE FRONT STARTS TO PUSH INTO THE
REGION. THE FRONT SLOWLY PUSHES ACROSS THE AREA ON TUESDAY AND
STALLS ALONG THE COAST TUESDAY NIGHT. SHOWER/STORMS WILL BE POSSIBLE
ON TUESDAY...ESPECIALLY ALONG THE FRONTAL BOUNDARY. BREEZY S-SW
WINDS FINALLY VEER TO THE W-NW BEHIND THE FRONT LATE TUESDAY. HIGH
PRESSURE RE-ESTABLISHES ITSELF OVER THE MID ATLANTIC STATES FROM
WEDNESDAY THROUGH AT LEAST SATURDAY.

&&

.MARINE...
SURFACE AND MID LEVEL TROUGHING WILL RESIDE OVER THE REGION TODAY.
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG THE
INLAND TROUGH AND ARE EXPECTED TO MOVE OVER THE WATERS MAINLY THIS
EVENING...AND AFTER MIDNIGHT BECOMING MORE FOCUSED OVER NRN CHES
BAY/NRN COASTAL WATERS. S-SW WINDS OVER ALL WATERS WILL AVERAGE
10-15 KT TODAY AND TONIGHT...AND WAVES/SEAS WILL AVERAGE 1-3 FT
(POSSIBLY UP TO 4 FT OUT NEAR 20 NM EARLY MONDAY MORNING).

A MORE SUBSTANTIAL SURFACE COLD FRONT APPROACHES FROM THE WEST ON
MONDAY. THIS WILL RESULT IN INCREASING SHOWER/THUNDERSTORM ACTIVITY
BY MONDAY EVENING AS THE FRONT BEGINS TO PUSH OVER THE WATERS. THE
FRONT SLOWLY PUSHES ACROSS THE WATERS ON TUESDAY AND STALLS ALONG
THE COAST TUESDAY NIGHT. SHOWER/STORMS WILL ALSO BE POSSIBLE ON
TUESDAY...ESPECIALLY ALONG THE FRONTAL BOUNDARY. BREEZY S-SW WINDS
MONDAY AND TUESDAY WILL AVERAGE 10-15 KT (UP TO 20 KT AT TIMES FOR
COASTAL WATERS)...THEN FINALLY VEER TO THE W-NW BEHIND THE FRONT
TUESDAY NIGHT. A COOL NW-N SURGE TUESDAY NIGHT INTO WEDNESDAY
MORNING MAY RESULT IN A PERIOD OF SCA HEADLINES...ALTHOUGH TIMING ON
THIS REMAINS UNCERTAIN. HIGH PRESSURE RE-ESTABLISHES ITSELF OVER THE
MID ATLANTIC STATES FROM WEDNESDAY THROUGH AT LEAST SATURDAY.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MAM
NEAR TERM...LSA
SHORT TERM...LKB/MAM
LONG TERM...JDM
AVIATION...BMD
MARINE...BMD







AREA FORECAST DISCUSSION

NWS BALTIMORE MD/WASHINGTON DC

 759 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER LAKE SUPERIOR WILL CONTINUE TO DEVELOP
AND MOVE EAST INTO NORTHERN QUEBEC THROUGH EARLY THIS WEEK. A
COLD FRONT ASSOCIATED WITH THIS LOW WILL MOVE THROUGH THE MID-
ATLANTIC MONDAY NIGHT INTO TUESDAY. HIGH PRESSURE BUILDS IN FROM
THE NORTHWEST MID TO LATE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEBRIS CLOUDS LEFT OVER FROM YDA`S CONVECTION HAS LIMITED EXTENT
OF FOG FORMATION ERY THIS MRNG. SOME PATCHY FOG WILL STILL DEVELOP
THRU DAYBREAK PRIMARILY WITHIN THE SHELTERED VLYS IN CENTRAL
VA...WHERE THE GROUND IS WET FROM YDA`S STORMS.

HIPRES WILL REMAIN PARKED OVER THE WRN ATLANTIC TDA. WITH PERSISTENT
SLY RETURN FLOW OVER THE ERN SEABOARD...THE AIRMASS WILL BE SIMILAR
TO YDA...WARM AND HUMID /DESPITE THE CALENDAR CHANGING FROM
METEOROLOGICAL SUMMER TO FALL/. MAX TEMPS ARE FCST IN MID TO UPPER
80S ALONG AND WEST OF THE BLUE RIDGE AND UPPER 80S TO LOWER 90S
FARTHER EAST. ONE MID-LVL SHORTWAVE TROUGH EXITS THE MID-ATLANTIC
REGION ERY THIS MRNG AS ANOTHER ONE APPROACHES FROM THE OH VLY. THE
REMNANTS OF THIS UPSTREAM MCS WILL PROGRESS EWD THRU THE NRN
MID-ATLANTIC STATES THIS AFTN/EVE. THE CWA WILL HAVE FILTERED
SUNSHINE BEFOREHAND...PROVIDING AN OPPORTUNITY FOR THE ATMOSPHERE TO
DESTABILIZE. SIMILAR TO YDA...SCT SHOWERS AND STORMS SHOULD DEVELOP
OVER THE MTS THIS AFTN AS MODEST LIFT FROM THE SHORTWAVE TROUGH
REACHES THE WRN CWA. WITH THE MID-LVL SUBSIDENCE INVERSION WEAKER
THAN YDA...DEEPER CONVECTION WILL HAVE A BETTER CHANCE TO MAKE IT
EAST OF THE MTS. THE BEST CHANCE FOR SHOWERS AND STORMS APPEAR TO BE
LATE THIS AFTN AND EVE WHEN THE SHORTWAVE TROUGH MOVES THRU. LIMITED
POPS TO CHANCE ACROSS THE ENTIRE CWA THOUGH AS CONVECTION MAY HAVE
DIFFICULTY ORGANIZING DUE TO WEAK SHEAR PROFILES AND LIFT FROM THE
TROUGH. FCST PARAMETERS FROM THE LATEST RAP INDICATE ABOUT 1500-2000
J/KG OF SBCAPE THIS AFTN. CANNOT RULE OUT A COUPLE OF PULSE SEVERE
STORMS ESPECIALLY IN THE MTS GIVEN THE THERMODYNAMIC PROFILES.

ONGOING CONVECTION WILL DIMINISH LATE THIS EVE WITH THE LOSS OF
HEATING AND AS THE SHORTWAVE TROUGH LIFTS NEWD TNGT. DRY SLOT MOVES
IN FROM THE WEST TNGT WHILE THE LLVL FLOW VEERS OUT OF THE WEST.
THIS COULD ALLOW FOR BREAKS IN THE CLOUD COVER AND FOR FOG TO
DEVELOP LATE TNGT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
LABOR DAY...ACTIVE WEATHER PATTERN CONTINUES WITH AN APPROACHING
COLD FRONT FROM THE WEST. A PREFRONTAL TROUGH WILL DEVELOP IN THE
LEE OF THE APPALACHIANS WHICH SHOULD PROVIDE A FOCUS FOR
ISOLATED/SCATTERED AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT. IT
WILL BE A HOT DAY WITH MAX TEMPS IN THE LOW 90S. NAM AND GFS HAVE
SBCAPE AROUND 2500 J/KG WITH BULK SHEAR UNDER 30 KT.

MONDAY NIGHT...LINES OF CONVECTION SHOULD DEVELOP AHEAD OF THE FRONT
AND PUSH EAST THROUGH THE AREA MONDAY EVENING/THROUGH MIDNIGHT.
INCREASED LIKELY POP COVERAGE TO ACROSS THE BALT-WASH METRO FOR THE
EVENING HOURS. THIS IS JUST ABOVE MOST GUIDANCE WHICH IS AROUND 50
POP. WITH AMPLE AVAILABLE ENERGY AND A STRAIGHT-LINE HODOGRAPH...
EXPECT ORGANIZED ACTIVITY. SEVERE THREAT OF LARGE HAIL AND DAMAGING
WIND. SPEAKING OF HAIL...THERE HAVE ONLY BEEN FOUR 1 INCH HAIL
REPORTS SINCE JULY 4. WITH TALL AND FAT CAPE DEPICTED BY THE NAM/GFS
SOUNDINGS...THIS HAIL DEARTH MAY END SOON. FRONT DRIFTS EAST THROUGH
THE NIGHT...MIN TEMPS AROUND 60F IN THE ALLEGHENY HIGHLANDS...CLOSER
TO 70F EAST OF THE BLUE RIDGE PER MAV/MET/SREF BLEND.

TUESDAY...FRONT IS SLOW TO CLEAR THE AREA...MAY STALL OVER SRN MD
CONTINUING A THUNDERSTORM THREAT DOWN THERE. OTW...NRN CONUS (NOT
QUITE CANADIAN...AND THUS NOT AS COOL) HIGH PRESSURE BUILDS IN FROM
THE NW...WITH SUNNY CONDITIONS ON TAP IN WRN PARTS OF THE CWA. MAX
TEMPS GENERALLY 80S AT LOW ELEVATIONS...MID 80S I-95 AND EAST.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
DRY CONDITIONS AS HIGH PRESSURE DOMINATES THROUGH FRIDAY. WEAK SFC
TROUGH DROPS SOUTH INTO THE CWA WEDNESDAY NIGHT...PUSHING SOUTH
THURSDAY. PROBABLY JUST SOME MID LEVEL CLOUDS ASSOCIATED WITH THIS
DISTURBANCE. MAX TEMPS CLOSE TO NORMAL...LOW 80S WED-FRI.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
LGT SLY WINDS AND MID TO HI CLOUDS HAVE LIMITED THE COVERAGE OF FOG
ERY THIS MRNG. AS OF 0730Z...ALL TERMINALS ARE VFR. CHO HAS THE BEST
OPPORTUNITY FOR A BRIEF PERIOD OF FOG TOWARD SUNRISE AS THE SOIL IS
SATURATED FROM YDA`S STORMS.

VFR CONDITIONS FOR MUCH OF TDA. SCT SHOWERS AND STORMS ARE EXPECTED
TO INITIALLY DEVELOP OVER THE MTS THIS AFTN AND MOVE EWD TOWARD THE
TERMINALS APPROX BETWEEN 20Z-01Z. TEMPORARY FLGT RESTRICTIONS
POSSIBLE WITH THESE STORMS. PATCHY FOG POSSIBLE AGAIN LATE
TNGT...ESPECIALLY AT THE FOG-PRONE LOCATIONS AT CHO AND MRB.

THUNDERSTORMS INCREASE MONDAY AFTERNOON/CONTINUE THROUGH THE NIGHT
AS A COLD FRONT DRIFTS EAST ACROSS THE TERMINALS. SLY FLOW AROUND 10
KT...THOUGH DAMAGING WINDS ARE POSSIBLE IN THUNDERSTORMS.  HIGH
PRESSURE THEN BUILDS TUESDAY AND DOMINATES REST OF THE WORK WEEK
WITH VFR CONDS OUTSIDE OF MORNING FOG.

&&

.MARINE...
SLY WINDS BETWEEN 10-15 KT WILL CONTINUE TDA AND TNGT. SCT STORMS
EXPECTED LATE IN THE DAY. LOCALLY STRONG WINDS WITH THESE STORMS
COULD BECOME HAZARDOUS TO MARINERS AND HOLIDAY BOATERS.

10-15 KT SLY FLOW AHEAD OF A COLD FRONT ACROSS THE WATERS MONDAY.
SPECIAL MARINE WARNINGS POSSIBLE FROM THUNDERSTORMS LATE MONDAY
AFTERNOON THROUGH THE NIGHT. FLOW BECOMES NWLY BY TUESDAY
EVENING...SOME CHANNELING GUSTS MAY APPROACH 18 KT. VARIABLE FLOW
AND HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.

&&

.CLIMATE...

FOR WASHINGTON DC (DCA)...
ALTHOUGH THE AVG TEMP OF 78.3F FOR THE 2013 METEOROLOGICAL SUMMER
WAS SLIGHTLY ABOVE THE 1981-2010 NORMAL...IT WAS CONSIDERABLY COOLER
THAN THE PREVIOUS THREE SUMMERS (WHICH WERE THE THREE WARMEST SUMMERS
ON RECORD FOR DC). BASED ON AVG TEMPS...THIS SUMMER RANKS AS THE
25TH WARMEST SUMMER ON RECORD (TIED WITH 1959). AUGUST 2013 WAS
THE FIRST SUMMER MONTH THAT WAS BELOW NORMAL SINCE JULY 2009.

MIN TEMPS WERE PARTICULARLY WARM. THE MIN TEMP FOR THE SUMMER
AVERAGED 70.8F...WHICH WAS THE TIED WITH 1980 FOR THE 4TH WARMEST
ON RECORD. THE ONLY THREE SUMMER THAT HAD A HIGHER MIN TEMP WAS
2010...2011 AND 2012. THE MIN TEMPERATURE WAS NEVER LOWER THAN
80F IN DC FOR FIVE STRAIGHT DAYS FROM 16-20 JULY...THE FIRST TIME
THIS HAD HAPPENED ON RECORD. THE MOST NUMBER OF DAYS IN A ROW
ABOVE 80F WAS PREVIOUSLY FOUR (21-24 JULY 2011).

A MAX TEMP OF 90F OR WARMER WAS RECORDED 23 DAYS THIS SUMMER.
LOOKING AT THE TEMP RECORDS SINCE 1871...THE AVERAGE NUMBER OF
90-DEGREE DAYS IN A SUMMER IS 26 FOR DC. THE NUMBER OF 90-DEGREE
DAYS IN THE PREVIOUS THREE SUMMERS WAS 52 IN 2010...47 IN 2011
AND 48 IN 2012.

THIS SUMMER FEATURED FIVE DAYS WITH A MAX TEMP OF 95F OR WARMER.
THE AVG NUMBER OF 95-DEGREE DAYS IN A SUMMER IS 6 FOR DC. A RECORD
28 95-DEGREE DAYS OCCURRED IN THE SUMMER OF 2012 WHILE 22 SUCH DAYS
WERE OBSERVED EACH IN 2010 AND 2011.

RAINFALL THIS SUMMER MEASURED 15.74 INCHES...WHICH IS EQUIVALENT TO
50 PERCENT ABOVE THE NORMAL SUMMER RAINFALL FOR DC. IT WAS THE WETTEST
SUMMER SINCE 2006 WHEN 18.61 INCHES WAS RECORDED. THE MAJORITY
(TWO-THIRDS) OF THE RAINFALL THIS SUMMER OCCURRED IN JUNE. JUNE 2013
WAS THE 4TH WETTEST JUNE ON RECORD.


FOR BALTIMORE (BWI)...
THE AVG TEMP OF 75.8F FOR THE 2013 METEOROLOGICAL SUMMER WAS
SLIGHTLY ABOVE THE 1981-2010 NORMAL BUT IT WAS CONSIDERABLY COOLER
THAN THE PREVIOUS THREE SUMMERS (WHICH WERE ALL IN THE TOP TEN
WARMEST SUMMERS ON RECORD). AUGUST 2013 WAS THE FIRST SUMMER MONTH
THAT WAS BELOW NORMAL SINCE JULY 2009.

A MAX TEMP OF 90F OR WARMER WAS RECORDED 19 DAYS THIS SUMMER.
LOOKING AT THE TEMP RECORDS SINCE 1872...THE AVERAGE NUMBER OF
90-DEGREE DAYS IN A SUMMER IS 23 FOR BALTIMORE. THE NUMBER OF
90-DEGREE DAYS DURING THE PREVIOUS THREE SUMMERS WAS 47 IN
2010...37 IN 2011 AND 40 IN 2012.

THIS SUMMER FEATURED ONLY FIVE DAYS WITH MAX TEMP OF 95F OR WARMER.
THE AVG NUMBER OF 95-DEGREE DAYS IN A SUMMER IS 6 FOR BALTIMORE. THE
NUMBER OF 90-DEGREE DAYS DURING THE PREVIOUS THREE SUMMERS WAS 19
IN 2010...16 IN 2011 AND 20 IN 2012.

RAINFALL THIS SUMMER MEASURED 12.16 INCHES...WHICH IS SLIGHTLY
WETTER THAN NORMAL. THE MAJORITY (TWO-THIRDS) OF THE RAINFALL THIS
SUMMER OCCURRED IN JUNE. JUNE 2013 WAS THE 7TH WETTEST JUNE ON
RECORD FOR BALTIMORE.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BAJ
NEAR TERM...JRK
SHORT TERM...BAJ
LONG TERM...BAJ
AVIATION...BAJ/JRK
MARINE...BAJ/JRK
CLIMATE...JRK








AREA FORECAST DISCUSSION

NWS BALTIMORE MD/WASHINGTON DC

 359 AM EDT SUN SEP 1 2013

.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER LAKE SUPERIOR WILL CONTINUE TO DEVELOP
AND MOVE EAST INTO NORTHERN QUEBEC THROUGH EARLY THIS WEEK. A
COLD FRONT ASSOCIATED WITH THIS LOW WILL MOVE THROUGH THE MID-
ATLANTIC MONDAY NIGHT INTO TUESDAY. HIGH PRESSURE BUILDS IN FROM
THE NORTHWEST MID TO LATE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEBRIS CLOUDS LEFT OVER FROM YDA`S CONVECTION HAS LIMITED EXTENT
OF FOG FORMATION ERY THIS MRNG. SOME PATCHY FOG WILL STILL DEVELOP
THRU DAYBREAK PRIMARILY WITHIN THE SHELTERED VLYS IN CENTRAL
VA...WHERE THE GROUND IS WET FROM YDA`S STORMS.

HIPRES WILL REMAIN PARKED OVER THE WRN ATLANTIC TDA. WITH PERSISTENT
SLY RETURN FLOW OVER THE ERN SEABOARD...THE AIRMASS WILL BE SIMILAR
TO YDA...WARM AND HUMID /DESPITE THE CALENDAR CHANGING FROM
METEOROLOGICAL SUMMER TO FALL/. MAX TEMPS ARE FCST IN MID TO UPPER
80S ALONG AND WEST OF THE BLUE RIDGE AND UPPER 80S TO LOWER 90S
FARTHER EAST. ONE MID-LVL SHORTWAVE TROUGH EXITS THE MID-ATLANTIC
REGION ERY THIS MRNG AS ANOTHER ONE APPROACHES FROM THE OH VLY. THE
REMNANTS OF THIS UPSTREAM MCS WILL PROGRESS EWD THRU THE NRN
MID-ATLANTIC STATES THIS AFTN/EVE. THE CWA WILL HAVE FILTERED
SUNSHINE BEFOREHAND...PROVIDING AN OPPORTUNITY FOR THE ATMOSPHERE TO
DESTABILIZE. SIMILAR TO YDA...SCT SHOWERS AND STORMS SHOULD DEVELOP
OVER THE MTS THIS AFTN AS MODEST LIFT FROM THE SHORTWAVE TROUGH
REACHES THE WRN CWA. WITH THE MID-LVL SUBSIDENCE INVERSION WEAKER
THAN YDA...DEEPER CONVECTION WILL HAVE A BETTER CHANCE TO MAKE IT
EAST OF THE MTS. THE BEST CHANCE FOR SHOWERS AND STORMS APPEAR TO BE
LATE THIS AFTN AND EVE WHEN THE SHORTWAVE TROUGH MOVES THRU. LIMITED
POPS TO CHANCE ACROSS THE ENTIRE CWA THOUGH AS CONVECTION MAY HAVE
DIFFICULTY ORGANIZING DUE TO WEAK SHEAR PROFILES AND LIFT FROM THE
TROUGH. FCST PARAMETERS FROM THE LATEST RAP INDICATE ABOUT 1500-2000
J/KG OF SBCAPE THIS AFTN. CANNOT RULE OUT A COUPLE OF PULSE SEVERE
STORMS ESPECIALLY IN THE MTS GIVEN THE THERMODYNAMIC PROFILES.

ONGOING CONVECTION WILL DIMINISH LATE THIS EVE WITH THE LOSS OF
HEATING AND AS THE SHORTWAVE TROUGH LIFTS NEWD TNGT. DRY SLOT MOVES
IN FROM THE WEST TNGT WHILE THE LLVL FLOW VEERS OUT OF THE WEST.
THIS COULD ALLOW FOR BREAKS IN THE CLOUD COVER AND FOR FOG TO
DEVELOP LATE TNGT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
LABOR DAY...ACTIVE WEATHER PATTERN CONTINUES WITH AN APPROACHING
COLD FRONT FROM THE WEST. A PREFRONTAL TROUGH WILL DEVELOP IN THE
LEE OF THE APPALACHIANS WHICH SHOULD PROVIDE A FOCUS FOR
ISOLATED/SCATTERED AFTERNOON SHOWER AND THUNDERSTORM DEVELOPMENT. IT
WILL BE A HOT DAY WITH MAX TEMPS IN THE LOW 90S. NAM AND GFS HAVE
SBCAPE AROUND 2500 J/KG WITH BULK SHEAR UNDER 30 KT.

MONDAY NIGHT...LINES OF CONVECTION SHOULD DEVELOP AHEAD OF THE FRONT
AND PUSH EAST THROUGH THE AREA MONDAY EVENING/THROUGH MIDNIGHT.
INCREASED LIKELY POP COVERAGE TO ACROSS THE BALT-WASH METRO FOR THE
EVENING HOURS. THIS IS JUST ABOVE MOST GUIDANCE WHICH IS AROUND 50
POP. WITH AMPLE AVAILABLE ENERGY AND A STRAIGHT-LINE HODOGRAPH...
EXPECT ORGANIZED ACTIVITY. SEVERE THREAT OF LARGE HAIL AND DAMAGING
WIND. SPEAKING OF HAIL...THERE HAVE ONLY BEEN FOUR 1 INCH HAIL
REPORTS SINCE JULY 4. WITH TALL AND FAT CAPE DEPICTED BY THE NAM/GFS
SOUNDINGS...THIS HAIL DEARTH MAY END SOON. FRONT DRIFTS EAST THROUGH
THE NIGHT...MIN TEMPS AROUND 60F IN THE ALLEGHENY HIGHLANDS...CLOSER
TO 70F EAST OF THE BLUE RIDGE PER MAV/MET/SREF BLEND.

TUESDAY...FRONT IS SLOW TO CLEAR THE AREA...MAY STALL OVER SRN MD
CONTINUING A THUNDERSTORM THREAT DOWN THERE. OTW...NRN CONUS (NOT
QUITE CANADIAN...AND THUS NOT AS COOL) HIGH PRESSURE BUILDS IN FROM
THE NW...WITH SUNNY CONDITIONS ON TAP IN WRN PARTS OF THE CWA. MAX
TEMPS GENERALLY 80S AT LOW ELEVATIONS...MID 80S I-95 AND EAST.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
DRY CONDITIONS AS HIGH PRESSURE DOMINATES THROUGH FRIDAY. WEAK SFC
TROUGH DROPS SOUTH INTO THE CWA WEDNESDAY NIGHT...PUSHING SOUTH
THURSDAY. PROBABLY JUST SOME MID LEVEL CLOUDS ASSOCIATED WITH THIS
DISTURBANCE. MAX TEMPS CLOSE TO NORMAL...LOW 80S WED-FRI.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
LGT SLY WINDS AND MID TO HI CLOUDS HAVE LIMITED THE COVERAGE OF FOG
ERY THIS MRNG. AS OF 0730Z...ALL TERMINALS ARE VFR. CHO HAS THE BEST
OPPORTUNITY FOR A BRIEF PERIOD OF FOG TOWARD SUNRISE AS THE SOIL IS
SATURATED FROM YDA`S STORMS.

VFR CONDITIONS FOR MUCH OF TDA. SCT SHOWERS AND STORMS ARE EXPECTED
TO INITIALLY DEVELOP OVER THE MTS THIS AFTN AND MOVE EWD TOWARD THE
TERMINALS APPROX BETWEEN 20Z-01Z. TEMPORARY FLGT RESTRICTIONS
POSSIBLE WITH THESE STORMS. PATCHY FOG POSSIBLE AGAIN LATE
TNGT...ESPECIALLY AT THE FOG-PRONE LOCATIONS AT CHO AND MRB.

THUNDERSTORMS INCREASE MONDAY AFTERNOON/CONTINUE THROUGH THE NIGHT
AS A COLD FRONT DRIFTS EAST ACROSS THE TERMINALS. SLY FLOW AROUND 10
KT...THOUGH DAMAGING WINDS ARE POSSIBLE IN THUNDERSTORMS.  HIGH
PRESSURE THEN BUILDS TUESDAY AND DOMINATES REST OF THE WORK WEEK
WITH VFR CONDS OUTSIDE OF MORNING FOG.

&&

.MARINE...
SLY CHANNELING HAS ENHANCED WINDS TO NEAR SCA THRESHOLD IN THE
TANGIER SOUND ERY THIS MRNG. HAVE AN MARINE WX STATEMENT FOR THIS
ZONE PUT OPTED TO NOT ISSUE A SCA AS THE PRESSURE GRADIENT WILL
CONTINUE TO WEAKEN OVER THE NEXT COUPLE OF HRS. OTHERWISE...SLY
WINDS BETWEEN 10-15 KT WILL CONTINUE TDA AND TNGT. SCT STORMS
EXPECTED LATE IN THE DAY. LOCALLY STRONG WINDS WITH THESE STORMS
COULD BECOME HAZARDOUS TO MARINERS AND HOLIDAY BOATERS.

10-15 KT SLY FLOW AHEAD OF A COLD FRONT ACROSS THE WATERS MONDAY.
SPECIAL MARINE WARNINGS POSSIBLE FROM THUNDERSTORMS LATE MONDAY
AFTERNOON THROUGH THE NIGHT. FLOW BECOMES NWLY BY TUESDAY
EVENING...SOME CHANNELING GUSTS MAY APPROACH 18 KT. VARIABLE FLOW
AND HIGH PRESSURE WEDNESDAY THROUGH FRIDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BAJ/JRK
NEAR TERM...JRK
SHORT TERM...BAJ
LONG TERM...BAJ
AVIATION...BAJ/JRK
MARINE...BAJ/JRK









AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 742 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 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 742 PM EDT MON SEP 2 2013

ALTHOUGH HIGH PRES CURRENTLY OVER THE UPPER MISSISSIPPI VALLEY WILL
STEADILY MOVE SE OVER THE NEXT 24HRS...ITS ASSOCIATED DRY AIR MASS
WILL DOMINATE THE AREA...RESULTING IN CLEAR SKIES/VFR CONDITIONS AT
KIWD/KCMX/KSAW THRU THIS FCST PERIOD.
&&

.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 UNTIL 6 AM EDT TUESDAY FOR MIZ005-006.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 402 PM EDT SUN SEP 1 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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 123 PM EDT SUN SEP 1 2013

OVERALL MVFR/VFR CONDITIONS THIS AFTN WL FALL TO IFR AT ALL 3 SITES
BY THIS EVNG FOLLOWING THE PASSAGE OF A COLD FNT AND THE DVLPMNT OF
A GUSTY UPSLOPE NNW WIND UNDER A SHARPENING PRES GRADIENT. SOME
-DZ/SPRINKLES ARE LIKELY AS WELL. AS THE GRADIENT/ UPSLOPE WIND
COMPONENT DIMINISH LATE TNGT/MON MRNG...CONDITIONS WL GRDLY IMPROVE
TO MVFR AND ANY LGT PCPN WL END.
&&

.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 FROM 8 PM EDT THIS EVENING THROUGH LATE
     MONDAY NIGHT FOR MIZ005-006.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...KC
MARINE...KC







AREA FORECAST DISCUSSION

NWS GAYLORD MI

 158 PM EDT SUN SEP 1 2013

.SYNOPSIS...
ISSUED AT 352 AM EDT SUN SEP 1 2013

A COLD FRONT WILL MOVE IN FROM THE WEST TODAY...BRINGING A CHANCE
FOR SHOWERS AND THUNDERSTORMS...THOUGH TEMPERATURES WILL REMAIN
RATHER WARM. BEHIND THE FRONT...ON LABOR DAY...IT WILL FEEL MUCH
MORE LIKE AUTUMN. MAINLY DRY AND SOMEWHAT WARMER WEATHER IS EXPECTED
FOR THE REMAINDER OF THE WEEK.

&&

.UPDATE...
ISSUED AT 158 PM EDT SUN SEP 1 2013

POTENT SHORT WAVE AND ATTENDING SFC LOW CONTINUES TO ADVANCE
THROUGH UPPER MICHIGAN/LAKE SUPERIOR THIS AFTERNOON...ASSOCIATED
COLD FRONT TRAILS DOWN THROUGH EAST-CENTRAL WISCONSIN. NICE BATCH
OF SHOWERS/THUNDER ADVANCING INTO ROUGHLY THE NRN HALF OF THE CWA
RIGHT ALONG THE EASTERN FRINGE OF THE SHORT WAVE...AND WITHIN A
NARROW CORRIDOR OF INSTABILITY ABOUT TO PUSH THROUGH THE REGION.
CONVECTION IS WEAKENING...RUNNING OUT AHEAD OF THE STRONGEST
FORCING AND INTO DECREASED INSTABILITY DOWNSTREAM. BUT HAVE LONG
AGO UPDATED POPS TO HAVE A PERIOD OF CATEGORICAL PRECIP ACROSS THE
NRN PART OF THE CWA...TRAILING OFF TO NOTHING SOUTH OF M-72.

REST OF THE AFTERNOON...INITIAL BATCH OF PRECIP WILL WORK THROUGH
THE NORTH OVER THE NEXT FEW HOURS. COLD FRONT STILL HAS TO COME
THROUGH THE REGION. STRATUS IS STARTING TO THIN ACROSS NRN LOWER
MICHIGAN WITH TEMPS STARTING TO WARM NICELY. STILL THINK THERE
WILL BE A WINDOW OF OPPORTUNITY FOR CONVECTION LATER THIS
AFTERNOON AS THE FRONT/COOLING ALOFT PRESSES THROUGH THE REGION...
PARTICULARLY OVER NE LOWER MICHIGAN WHERE CONVERGENCE WILL BE
MAXIMIZED.

UPDATE ISSUED AT 1032 AM EDT SUN SEP 1 2013

OVERVIEW: COMPACT SHORT WAVE NOW ADVANCING THROUGH THE WESTERN
U.P./WESTERN LAKE SUPERIOR. ATTENDING SFC LOW LOCATED OVER THE
KEWEENAW PENINSULA AS OF 14Z WITH A COLD FRONT STRETCHING DOWN
THROUGH CENTRAL WISCONSIN. AHEAD OF THE FRONT...12Z GRB/APX
SOUNDINGS REVEAL A FAIRLY DRY LOWER LEVEL AIRMASS IN PLACE AND
SFC BASED CAP UP THROUGH AROUND 800 MB OR SO.

BUT...THERE IS A THIN RIBBON OF MODEST LOW LEVEL MOISTURE (850
THETA-E RIDGE) JUST ALONG THE FRONT IN CENTRAL WISCONSIN...
WRAPPING INTO THE LOW OVER LAKE SUPERIOR. COUPLED WITH COOLING
LOWER LEVELS WITH THE SFC FRONT AND UPPER WAVE...HAS PRODUCED A
NARROW CORRIDOR OF INSTABILITY THAT IS ADVANCING EASTWARD...
EVIDENCED BY THE BKN LINE OF CONVECTION THAT WRAPS ALONG THE
LEADING EDGE OF THE SHORT WAVE.

FORECAST FOR THIS AFTERNOON/EVENING IS COMPLICATED BY A NUMBER OF
FACTORS...INCLUDING...BUT NOT LIMITED TO...MORNING STRATUS AND FOG
THAT WILL MOST CERTAINLY INHIBIT HEATING AND INSTABILITY AT LEAST
FOR AWHILE...AS WELL AS SMALLER SCALE AFFECTS ON THE LOW LEVEL
WIND FIELD INDUCED BY THE LAKES THAT WILL IMPACT FRONTAL POSITION
AND ULTIMATELY LOW LEVEL CONVERGENCE.

THROUGH EARLY AFTERNOON...ONGOING CONVECTION UPSTREAM SHOULD
BASICALLY HIT A "CINH" WALL AS IT TRIES TO ADVANCE INTO THIS
CWA...ESSENTIALLY OUTRUNNING THE FORCING AND AFOREMENTIONED NARROW
CORRIDOR OF INSTABILITY. SO...EXPECT MUCH OF THE CURRENT ACTIVITY
TO FIZZLE. MAIN EXCEPTION...ACROSS UPPER MICHIGAN ALONG THE SHORT
WAVE TRACK WHERE STRONGEST QG-FORCING WILL PROBABLY SUSTAIN
SHOWERS INTO EASTERN UPPER MICHIGAN PAST LUNCH TIME.

THEN...UPSTREAM SFC FRONT WILL TRY TO ADVANCE INTO THE CWA DURING
THE COURSE OF THE AFTERNOON...ALTHOUGH DUE TO LAKE INDUCED CHANGES
IN THE LOW LEVEL WIND FIELD...FRONT AND ASSOCIATED LOW LEVEL
CONVERGENCE WILL LIKELY LOSE IT/S IDENTITY. FRONT MAY "JUMP" INTO
NORTHEAST LOWER MICHIGAN THIS AFTERNOON AIDED BY SE FLOW OF LAKE
HURON. PROVIDED WE CAN EVENTUALLY THIN OUT THE STRATUS AND FOG BY
EARLY-MID AFTERNOON...WE MIGHT BE ABLE TO GENERATE SOME
INSTABILITY AS THE AFOREMENTIONED LOWER LEVEL MOISTURE AXIS NOSES
UP THROUGH NE LOWER MICHIGAN ALONG THE FRONT. WILL SEE HOW THIS
GOES.

BUT AT THIS POINT...THE BEST PRECIP CHANCES THROUGH THIS EVENING
ARE SETTING UP FOR EASTER UPPER MICHIGAN (ALONG THE SHORT WAVE
TRACK)...AS WELL AS NORTHEAST LOWER...THAT IS IF WE CAN MUSTER
SOME HEATING AND DESTABILIZATION. CERTAINLY NOT A RAIN OUT EVENT
BY ANY STRETCH. BUT FOLKS MAKING OUTDOOR HOLIDAY PLANS SHOULD AT
LEAST PLAN FOR THE POTENTIAL FOR A PERIOD OF SHOWERS AND SOME
THUNDER...ESPECIALLY IN EASTERN UPPER AND NORTHEAST LOWER.

SEVERE THREAT...AGAIN INSTABILITY DEPENDENT. WIDESPREAD SEVERE WEATHER
NOT ANTICIPATED. BUT...MID LEVEL FLOW DOES INCREASE TO 35 TO 4O
KNOTS ALONG THE FRONT...LEADING TO SOME BULK SHEAR TO CAPITALIZE
ON. COMBINED WITH BACKED FLOW OFF LAKE HURON...ANY STORMS THAT
MANAGE TO DEVELOP IN NE LOWER MICHIGAN WILL BEAR SCRUTINY.

UPDATE ISSUED AT 703 AM EDT SUN SEP 1 2013

STRATUS HAS BECOME FAIRLY WIDESPREAD COMING IN OFF LAKE
HURON...AND AIDED BY EXCELLENT COOLING OF THE BL. FOG ALSO WAS
COMMON...BUT NOT WIDESPREAD...YET DENSE IN SPOTS. STRATUS WILL
LIKELY LINGER FOR A BIT...WHILE HIGHER LEVEL CLOUDS STREAM IN FROM
THE WEST. ALSO...A CLUSTER OF SHOWERS AND STORMS WILL ROLL IN FROM
NE WISCONSIN/CENTRAL UPPER...AND LIKELY SCRAPE WESTERN SECTIONS OF
CHIP/MACK...MAYBE FAR NRN LAKE MICHIGAN. NOT TOTALLY SURE OF THE
EVOLUTION OF THIS PRECIP...AS IT SHOULD BE MORE DRIVEN BY THE H8
WESTERLY LLJ OUT TO OUR WEST. THAT SAID...UPPER LEVEL SHORTWAVE
WILL ALREADY BE THROWING SOME ENERGY IN ACROSS THESE AREAS AS
WELL. WILL START CHANCES FOR RAIN A COUPLE HOURS EARLIER...MID
MORNING FOR EASTERN UPPER.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT SUN SEP 1 2013

CONDITIONS ARE SET TO CHANGE OVER THE NEXT 24-30 HRS...AS A COLD
FRONT WILL BLOW THROUGH THE REGION WITH WARM/MUGGY SUMMER WEATHER
WILL TURN MUCH COOLER AND BREEZY FOR THE START OF NEXT WORK WEEK.
MAIN ISSUE IS THE STRENGTH AND COVERAGE OF SHOWERS AND STORMS WITH
THE FRONT.

CURRENTLY...CLEARLY EVIDENT SHORTWAVE SEEN DROPPING SE ACROSS FAR
NRN MN WITH ASSOCIATED SFC LOW PRESSURE OVER THE ARROWHEAD. A COLD
FRONT EXTENDED FROM THIS LOW PRESSURE BACK ACROSS MN AND FAR FAR
NW IOWA. SHOWERS AND STORMS HAVE REALLY FALLEN APART ACROSS THE
ENTIRE FRONT...WITH LOSS OF DIURNAL HEATING. LATEST RUC ANALYSIS
SHOWING PRESENCE OF AN ELEVATED WARM FRONT WITH 30-35KTS OF A
WESTERLY JET...WARM/MOIST CONVERGENCE PIN-POINTED ON EASTERN
UPPER. SKIES WERE CLEAR HOWEVER...WITH ONLY SOME THIN HIGH LEVEL
CLOUDS IN EASTERN UPPER FROM EARLIER SHOWERS AND STORMS ACROSS
WISCONSIN. THESE CLOUDS AND EVEN PRECIP HAD PROBLEMS HOLDING
TOGETHER AS THEY WORKED THEIR WAY WEST INTO RELATIVELY DRIER AIR
MASS CENTERED RIGHT OVER NRN MICHIGAN. DID SEE A FEW LIGHT RAIN
SHOWERS/SPRINKLES DOTTING EASTERN UPPER...OTHERWISE...THERE WAS
ABSOLUTELY NO PRECIP NEAR NRN MICHIGAN. THE MAIN ACTION WAS STUCK
ACROSS IOWA IN BETTER LOW LEVEL CONVERGENCE AND INSTABILITY. A
MUGGY SFC AIR MASS AND THE CLEAR SKIES HAS RESULTED IN PATCHY
AREAS OF FOG THAT HAS BEEN LOCALLY DENSE. TEMPERATURES IN UPPER
50S TO LOWER HALF OF THE 60S FOR MOST.

TODAY AND TONIGHT...SOME ADDITIONAL UPSTREAM HIGH LEVEL CLOUDS
WILL SWEEP IN OVER THE AREA 09-12Z...ESPECIALLY EASTERN
UPPER...BUT WILL LIKELY STILL HAVE A HARD TIME NOT THINNING EVEN
MORE. THUS...BELIEVE THE SKY COVER WILL BE RATHER CLEAR FOR ALL TO
START THE DAY. CHANCES FOR PRECIPITATION WERE REMOVED THROUGH 15Z
BASED ON THE AFOREMENTIONED. A DECENT WARMING PERIOD WILL GET
TEMPERATURES IN THE UPPER 70S NORTH...TO THE LOWER HALF OF THE 80S
IN NRN LOWER TODAY. WINDS WILL BE LIGHT OUT OF THE S/SE...THUS
LIGHT WINDS. THESE WINDS WILL TRY AND TURN ONSHORE AS WE HEAD
THROUGH THE AFTERNOON...CREATING A POCKET OF BETTER LOW LEVEL
CONVERGENCE ACROSS PORTIONS OF NE LOWER. AS THE FRONT NEARS THE
WESTERN CWA LATE THIS AFTERNOON...AND CROSSES NE LOWER AFTER THE
EVENING...WEAK H8-H7 WAA...DPVA AND H4-H2 UPPER DIVERGENCE IN
LEFT EXIT REGION OF AN UPPER JETLET...WILL COMBINE WITH DIURNAL
HEATING/DESTABILIZATION FOR A CHANCE AT SHOWERS AND STORMS.
PROBLEMS...UPPER WAVE STARTS TO LIFT NE AND SHEAR OF THE MEAGER
CORRIDOR OF DEEPER MOISTURE. PLUS...CAPPING AROUND 800MB AND LACK
OF ANY APPRECIABLE LL MOISTURE SHOWS QUITE A BIT OF CINH (40J/KG)
FOR MUCH OF THE DAY. THIS CAPPING DOES GET ERODED...BUT NOT UNTIL
THE FRONT ARRIVES. THIS WILL LEAVE A PERIOD OF POSSIBLE SHOWERS
AND STORMS...WHICH WILL MORE LIKELY LAST FOR 3-5 HRS ON/NEAR THE
FRONT. WIND FIELDS NOT OVERLY IMPRESSIVE WITH 0-6KM BULK SHEAR AT
30KTS...AND WET BULBS AT 11KFT ARE KIND OF HIGH. HOWEVER...DECENT
HEATING TO START THE DAY...MLCAPE OF 1500 J/KG POSSIBLE...THEN A
LOW END THREAT FOR DAMAGING WINDS AND ISOLATED LARGE HAIL WITH EH
STRONGER CELLS ARE POSSIBLE. WE ARE NOT IN A SLIGHT RISK RIGHT
NOW...AND THIS WOULD CERTAINLY NOT BE A WIDESPREAD SEVERE THREAT.
THE FRONT CROSSES NE LOWER BY MIDNIGHT...WITH A GRADUALLY
INCREASING/STRENGTHENING PRESSURE GRADIENT RESULTING IN A GROWING
COLD ADVECTION REGIME WITH BREEZIER WINDS TOWARD
DAYBREAK...ESPECIALLY DOWNWIND OF LAKE MICHIGAN AND WHITEFISH BAY.
LOW TEMPS TO FALL INTO THE 50S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 352 AM EDT SUN SEP 1 2013

INCREASING RIDGING TO START THE PERIOD TUESDAY WHICH HOLDS THROUGH
MUCH OF WEDNESDAY. THE RIDGE THEN GETS TEMPORARILY KNOCKED DOWN
LATER WEDNESDAY INTO WEDNESDAY NIGHT AS A MOISTURE STARVED SHORT
WAVE MOVES THROUGH THE FLOW. RIDGING THEN TAKES OVER ONCE AGAIN LATE
IN THE WEEK INTO THE FIRST HALF OF NEXT WEEKEND AHEAD OF THE NEXT
TROUGH. OVERALL DRY WEATHER IS EXPECTED...THOUGH THERE MAY END UP
BEING SLIGHT CHANCES FOR SHOWERS LATE IN THE WEEK. THE MAIN LONG
TERM FORECAST CONCERNS CENTER AROUND CLOUD COVER AND HIGH
TEMPERATURES MONDAY THEN POPS TO END THE PERIOD.

LABOR DAY...SHARPLY COOLER CONDITIONS ARE EXPECTED. MODEL SOUNDINGS
AND CROSS SECTIONS SHOW A DECENT AMOUNT OF MOISTURE AT LOWER LEVELS.
THIS SHOULD RESULT IN LOTS OF CLOUDS AND POSSIBLE DRIZZLE ACROSS
NORTHERN AREAS AS AN UPPER LEVEL TROUGH MOVES BY TO OUR NORTHEAST.
ACROSS SOUTHERN ZONES...THERE COULD END UP BEING A BIT LESS CLOUD
COVER WHICH MAY TEMPER TEMPERATURES. HIGHS ONLY RANGING FROM THE
LOWER 60S NORTH TO AROUND 70 SOUTHEAST.

MONDAY NIGHT THROUGH TUESDAY NIGHT...SEASONABLE WEATHER IS EXPECTED
AS SURFACE HIGH PRESSURE TEMPORARILY SEIZES CONTROL. LOWS IN THE 40S
TO LOWER 50S. HIGHS TUESDAY REBOUNDING INTO THE LOWER AND MIDDLE
70S.

WEDNESDAY INTO THURSDAY...A MOISTURE STARVED UPPER LEVEL SHORT WAVE
AND SURFACE COLD FRONT MOVE ACROSS THE REGION. AT THIS POINT NO
PRECIPITATION IS EXPECTED. WARMER WEDNESDAY WITH HIGHS RANGING FROM
AROUND 70 NORTH TO THE UPPER 70S SOUTHEAST. COOLER THURSDAY WITH
HIGHS RANGING FROM THE MIDDLE 60S TO LOWER 70S.

FRIDAY INTO SATURDAY...THE UPPER LEVEL RIDGE LOOKS TO NOSE EASTWARD
INTO OUR NECK OF THE WOODS...WHICH BODES WELL FOR ANOTHER WARMING
TREND SETTING IN TO ROUND OUT THE WEEK. THERE COULD BE SOME
INSTABILITY DRIVEN SHOWERS...BUT EXTENDED MODELS DISAGREE ON THE
AMOUNT OF AVAILABLE MOISTURE AS WELL AS THE STRENGTH OF A POSSIBLE
CAPPING INVERSION ALOFT SO WILL CONTINUE TO LEAVE OUT POPS AT THIS
TIME. HIGHS BOTH DAYS RANGING FROM THE LOWER AND MIDDLE 70S FAR
NORTH TO AROUND 80 SOUTH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 158 PM EDT SUN SEP 1 2013

LINE OF SHOWERS/THUNDER WILL IMPACT PLN OVER THE NEXT 1 TO 2
HOURS. OTHERWISE...VFR CIGS SLOWLY EMERGING ACROSS NRN LOWER
MICHIGAN. COLD FRONT EXPECTED TO SWING THROUGH THE REGION LATE
THIS AFTERNOON/EARLY EVENING AND MAY YET SPARK ADDITIONAL SHOWERS
AND STORMS ACROSS NRN LOWER MICHIGAN...ESPECIALLY NE LOWER
MICHIGAN. BEHIND THE FRONT...MUCH COOLER AIR WILL SPREAD INTO THE
REGION TONIGHT. THIS WILL LEAD TO ABUNDANT STATUS EXPANDING DOWN
INTO THE REGION DURING THE OVERNIGHT PERIOD THAT WILL PERSIST
THROUGH MUCH OF LABOR DAY.

WINDS TURN NORTHWEST TONIGHT WITH SOME GUSTINESS THROUGH THE DAY
MONDAY.

&&

.MARINE...
ISSUED AT 352 AM EDT SUN SEP 1 2013

A WEAK S/SE WIND TODAY AHEAD OF AN APPROACHING COLD FRONT...WILL
TRY AND TURN MORE ONSHORE THIS AFTERNOON DUE TO ANTICIPATED LAKE
BREEZES. THIS WILL CHANGE THROUGH THE NIGHT...AS A PERIOD OF
SCATTERED SHOWERS AND STORMS WILL BLOW THROUGH ALONG WITH THE COLD
FRONT. BEHIND THIS FRONT...WINDS WILL SHIFT ABRUPTLY OUT OF THE
NW....WHILE OVERLAKE INSTABILITY DEVELOPS AND A TIGHTER PRESSURE
GRADIENT SETTLES IN OVER THE GREAT LAKES. ADVISORY LEVEL WINDS ARE
LIKELY MONDAY AND MONDAY NIGHT IN MANY OF THE NEARSHORE WATERS.
THIS IS ESPECIALLY TRUE FOR PRESQUE ISLE LIGHT/NE LOWER MICHIGAN
NEARSHORES. HIGHER PRESSURE THEN BUILDS IN FOR QUIETER/CALMER
BOATING CONDITIONS FOR THE REMAINDER OF THE WORK WEEK.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 11 PM EDT MONDAY
     FOR LMZ323-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 11 PM EDT MONDAY
     FOR LSZ321.

&&

$$

UPDATE...BA
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...BA
MARINE...SD








AREA FORECAST DISCUSSION

NWS GAYLORD MI

 1032 AM EDT SUN SEP 1 2013

.SYNOPSIS...
ISSUED AT 352 AM EDT SUN SEP 1 2013

A COLD FRONT WILL MOVE IN FROM THE WEST TODAY...BRINGING A CHANCE
FOR SHOWERS AND THUNDERSTORMS...THOUGH TEMPERATURES WILL REMAIN
RATHER WARM. BEHIND THE FRONT...ON LABOR DAY...IT WILL FEEL MUCH
MORE LIKE AUTUMN. MAINLY DRY AND SOMEWHAT WARMER WEATHER IS EXPECTED
FOR THE REMAINDER OF THE WEEK.

&&

.UPDATE...
ISSUED AT 1032 AM EDT SUN SEP 1 2013

OVERVIEW: COMPACT SHORT WAVE NOW ADVANCING THROUGH THE WESTERN
U.P./WESTERN LAKE SUPERIOR. ATTENDING SFC LOW LOCATED OVER THE
KEWEENAW PENINSULA AS OF 14Z WITH A COLD FRONT STRETCHING DOWN
THROUGH CENTRAL WISCONSIN. AHEAD OF THE FRONT...12Z GRB/APX
SOUNDINGS REVEAL A FAIRLY DRY LOWER LEVEL AIRMASS IN PLACE AND
SFC BASED CAP UP THROUGH AROUND 800 MB OR SO.

BUT...THERE IS A THIN RIBBON OF MODEST LOW LEVEL MOISTURE (850
THETA-E RIDGE) JUST ALONG THE FRONT IN CENTRAL WISCONSIN...
WRAPPING INTO THE LOW OVER LAKE SUPERIOR. COUPLED WITH COOLING
LOWER LEVELS WITH THE SFC FRONT AND UPPER WAVE...HAS PRODUCED A
NARROW CORRIDOR OF INSTABILITY THAT IS ADVANCING EASTWARD...
EVIDENCED BY THE BKN LINE OF CONVECTION THAT WRAPS ALONG THE
LEADING EDGE OF THE SHORT WAVE.

FORECAST FOR THIS AFTERNOON/EVENING IS COMPLICATED BY A NUMBER OF
FACTORS...INCLUDING...BUT NOT LIMITED TO...MORNING STRATUS AND FOG
THAT WILL MOST CERTAINLY INHIBIT HEATING AND INSTABILITY AT LEAST
FOR AWHILE...AS WELL AS SMALLER SCALE AFFECTS ON THE LOW LEVEL
WIND FIELD INDUCED BY THE LAKES THAT WILL IMPACT FRONTAL POSITION
AND ULTIMATELY LOW LEVEL CONVERGENCE.

THROUGH EARLY AFTERNOON...ONGOING CONVECTION UPSTREAM SHOULD
BASICALLY HIT A "CINH" WALL AS IT TRIES TO ADVANCE INTO THIS
CWA...ESSENTIALLY OUTRUNNING THE FORCING AND AFOREMENTIONED NARROW
CORRIDOR OF INSTABILITY. SO...EXPECT MUCH OF THE CURRENT ACTIVITY
TO FIZZLE. MAIN EXCEPTION...ACROSS UPPER MICHIGAN ALONG THE SHORT
WAVE TRACK WHERE STRONGEST QG-FORCING WILL PROBABLY SUSTAIN
SHOWERS INTO EASTERN UPPER MICHIGAN PAST LUNCH TIME.

THEN...UPSTREAM SFC FRONT WILL TRY TO ADVANCE INTO THE CWA DURING
THE COURSE OF THE AFTERNOON...ALTHOUGH DUE TO LAKE INDUCED CHANGES
IN THE LOW LEVEL WIND FIELD...FRONT AND ASSOCIATED LOW LEVEL
CONVERGENCE WILL LIKELY LOSE IT/S IDENTITY. FRONT MAY "JUMP" INTO
NORTHEAST LOWER MICHIGAN THIS AFTERNOON AIDED BY SE FLOW OF LAKE
HURON. PROVIDED WE CAN EVENTUALLY THIN OUT THE STRATUS AND FOG BY
EARLY-MID AFTERNOON...WE MIGHT BE ABLE TO GENERATE SOME
INSTABILITY AS THE AFOREMENTIONED LOWER LEVEL MOISTURE AXIS NOSES
UP THROUGH NE LOWER MICHIGAN ALONG THE FRONT. WILL SEE HOW THIS
GOES.

BUT AT THIS POINT...THE BEST PRECIP CHANCES THROUGH THIS EVENING
ARE SETTING UP FOR EASTER UPPER MICHIGAN (ALONG THE SHORT WAVE
TRACK)...AS WELL AS NORTHEAST LOWER...THAT IS IF WE CAN MUSTER
SOME HEATING AND DESTABILIZATION. CERTAINLY NOT A RAIN OUT EVENT
BY ANY STRETCH. BUT FOLKS MAKING OUTDOOR HOLIDAY PLANS SHOULD AT
LEAST PLAN FOR THE POTENTIAL FOR A PERIOD OF SHOWERS AND SOME
THUNDER...ESPECIALLY IN EASTERN UPPER AND NORTHEAST LOWER.

SEVERE THREAT...AGAIN INSTABILITY DEPENDENT. WIDESPREAD SEVERE WEATHER
NOT ANTICIPATED. BUT...MID LEVEL FLOW DOES INCREASE TO 35 TO 4O
KNOTS ALONG THE FRONT...LEADING TO SOME BULK SHEAR TO CAPITALIZE
ON. COMBINED WITH BACKED FLOW OFF LAKE HURON...ANY STORMS THAT
MANAGE TO DEVELOP IN NE LOWER MICHIGAN WILL BEAR SCRUTINY.


UPDATE ISSUED AT 703 AM EDT SUN SEP 1 2013

STRATUS HAS BECOME FAIRLY WIDESPREAD COMING IN OFF LAKE
HURON...AND AIDED BY EXCELLENT COOLING OF THE BL. FOG ALSO WAS
COMMON...BUT NOT WIDESPREAD...YET DENSE IN SPOTS. STRATUS WILL
LIKELY LINGER FOR A BIT...WHILE HIGHER LEVEL CLOUDS STREAM IN FROM
THE WEST. ALSO...A CLUSTER OF SHOWERS AND STORMS WILL ROLL IN FROM
NE WISCONSIN/CENTRAL UPPER...AND LIKELY SCRAPE WESTERN SECTIONS OF
CHIP/MACK...MAYBE FAR NRN LAKE MICHIGAN. NOT TOTALLY SURE OF THE
EVOLUTION OF THIS PRECIP...AS IT SHOULD BE MORE DRIVEN BY THE H8
WESTERLY LLJ OUT TO OUR WEST. THAT SAID...UPPER LEVEL SHORTWAVE
WILL ALREADY BE THROWING SOME ENERGY IN ACROSS THESE AREAS AS
WELL. WILL START CHANCES FOR RAIN A COUPLE HOURS EARLIER...MID
MORNING FOR EASTERN UPPER.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT SUN SEP 1 2013

CONDITIONS ARE SET TO CHANGE OVER THE NEXT 24-30 HRS...AS A COLD
FRONT WILL BLOW THROUGH THE REGION WITH WARM/MUGGY SUMMER WEATHER
WILL TURN MUCH COOLER AND BREEZY FOR THE START OF NEXT WORK WEEK.
MAIN ISSUE IS THE STRENGTH AND COVERAGE OF SHOWERS AND STORMS WITH
THE FRONT.

CURRENTLY...CLEARLY EVIDENT SHORTWAVE SEEN DROPPING SE ACROSS FAR
NRN MN WITH ASSOCIATED SFC LOW PRESSURE OVER THE ARROWHEAD. A COLD
FRONT EXTENDED FROM THIS LOW PRESSURE BACK ACROSS MN AND FAR FAR
NW IOWA. SHOWERS AND STORMS HAVE REALLY FALLEN APART ACROSS THE
ENTIRE FRONT...WITH LOSS OF DIURNAL HEATING. LATEST RUC ANALYSIS
SHOWING PRESENCE OF AN ELEVATED WARM FRONT WITH 30-35KTS OF A
WESTERLY JET...WARM/MOIST CONVERGENCE PIN-POINTED ON EASTERN
UPPER. SKIES WERE CLEAR HOWEVER...WITH ONLY SOME THIN HIGH LEVEL
CLOUDS IN EASTERN UPPER FROM EARLIER SHOWERS AND STORMS ACROSS
WISCONSIN. THESE CLOUDS AND EVEN PRECIP HAD PROBLEMS HOLDING
TOGETHER AS THEY WORKED THEIR WAY WEST INTO RELATIVELY DRIER AIR
MASS CENTERED RIGHT OVER NRN MICHIGAN. DID SEE A FEW LIGHT RAIN
SHOWERS/SPRINKLES DOTTING EASTERN UPPER...OTHERWISE...THERE WAS
ABSOLUTELY NO PRECIP NEAR NRN MICHIGAN. THE MAIN ACTION WAS STUCK
ACROSS IOWA IN BETTER LOW LEVEL CONVERGENCE AND INSTABILITY. A
MUGGY SFC AIR MASS AND THE CLEAR SKIES HAS RESULTED IN PATCHY
AREAS OF FOG THAT HAS BEEN LOCALLY DENSE. TEMPERATURES IN UPPER
50S TO LOWER HALF OF THE 60S FOR MOST.

TODAY AND TONIGHT...SOME ADDITIONAL UPSTREAM HIGH LEVEL CLOUDS
WILL SWEEP IN OVER THE AREA 09-12Z...ESPECIALLY EASTERN
UPPER...BUT WILL LIKELY STILL HAVE A HARD TIME NOT THINNING EVEN
MORE. THUS...BELIEVE THE SKY COVER WILL BE RATHER CLEAR FOR ALL TO
START THE DAY. CHANCES FOR PRECIPITATION WERE REMOVED THROUGH 15Z
BASED ON THE AFOREMENTIONED. A DECENT WARMING PERIOD WILL GET
TEMPERATURES IN THE UPPER 70S NORTH...TO THE LOWER HALF OF THE 80S
IN NRN LOWER TODAY. WINDS WILL BE LIGHT OUT OF THE S/SE...THUS
LIGHT WINDS. THESE WINDS WILL TRY AND TURN ONSHORE AS WE HEAD
THROUGH THE AFTERNOON...CREATING A POCKET OF BETTER LOW LEVEL
CONVERGENCE ACROSS PORTIONS OF NE LOWER. AS THE FRONT NEARS THE
WESTERN CWA LATE THIS AFTERNOON...AND CROSSES NE LOWER AFTER THE
EVENING...WEAK H8-H7 WAA...DPVA AND H4-H2 UPPER DIVERGENCE IN
LEFT EXIT REGION OF AN UPPER JETLET...WILL COMBINE WITH DIURNAL
HEATING/DESTABILIZATION FOR A CHANCE AT SHOWERS AND STORMS.
PROBLEMS...UPPER WAVE STARTS TO LIFT NE AND SHEAR OF THE MEAGER
CORRIDOR OF DEEPER MOISTURE. PLUS...CAPPING AROUND 800MB AND LACK
OF ANY APPRECIABLE LL MOISTURE SHOWS QUITE A BIT OF CINH (40J/KG)
FOR MUCH OF THE DAY. THIS CAPPING DOES GET ERODED...BUT NOT UNTIL
THE FRONT ARRIVES. THIS WILL LEAVE A PERIOD OF POSSIBLE SHOWERS
AND STORMS...WHICH WILL MORE LIKELY LAST FOR 3-5 HRS ON/NEAR THE
FRONT. WIND FIELDS NOT OVERLY IMPRESSIVE WITH 0-6KM BULK SHEAR AT
30KTS...AND WET BULBS AT 11KFT ARE KIND OF HIGH. HOWEVER...DECENT
HEATING TO START THE DAY...MLCAPE OF 1500 J/KG POSSIBLE...THEN A
LOW END THREAT FOR DAMAGING WINDS AND ISOLATED LARGE HAIL WITH EH
STRONGER CELLS ARE POSSIBLE. WE ARE NOT IN A SLIGHT RISK RIGHT
NOW...AND THIS WOULD CERTAINLY NOT BE A WIDESPREAD SEVERE THREAT.
THE FRONT CROSSES NE LOWER BY MIDNIGHT...WITH A GRADUALLY
INCREASING/STRENGTHENING PRESSURE GRADIENT RESULTING IN A GROWING
COLD ADVECTION REGIME WITH BREEZIER WINDS TOWARD
DAYBREAK...ESPECIALLY DOWNWIND OF LAKE MICHIGAN AND WHITEFISH BAY.
LOW TEMPS TO FALL INTO THE 50S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 352 AM EDT SUN SEP 1 2013

INCREASING RIDGING TO START THE PERIOD TUESDAY WHICH HOLDS THROUGH
MUCH OF WEDNESDAY. THE RIDGE THEN GETS TEMPORARILY KNOCKED DOWN
LATER WEDNESDAY INTO WEDNESDAY NIGHT AS A MOISTURE STARVED SHORT
WAVE MOVES THROUGH THE FLOW. RIDGING THEN TAKES OVER ONCE AGAIN LATE
IN THE WEEK INTO THE FIRST HALF OF NEXT WEEKEND AHEAD OF THE NEXT
TROUGH. OVERALL DRY WEATHER IS EXPECTED...THOUGH THERE MAY END UP
BEING SLIGHT CHANCES FOR SHOWERS LATE IN THE WEEK. THE MAIN LONG
TERM FORECAST CONCERNS CENTER AROUND CLOUD COVER AND HIGH
TEMPERATURES MONDAY THEN POPS TO END THE PERIOD.

LABOR DAY...SHARPLY COOLER CONDITIONS ARE EXPECTED. MODEL SOUNDINGS
AND CROSS SECTIONS SHOW A DECENT AMOUNT OF MOISTURE AT LOWER LEVELS.
THIS SHOULD RESULT IN LOTS OF CLOUDS AND POSSIBLE DRIZZLE ACROSS
NORTHERN AREAS AS AN UPPER LEVEL TROUGH MOVES BY TO OUR NORTHEAST.
ACROSS SOUTHERN ZONES...THERE COULD END UP BEING A BIT LESS CLOUD
COVER WHICH MAY TEMPER TEMPERATURES. HIGHS ONLY RANGING FROM THE
LOWER 60S NORTH TO AROUND 70 SOUTHEAST.

MONDAY NIGHT THROUGH TUESDAY NIGHT...SEASONABLE WEATHER IS EXPECTED
AS SURFACE HIGH PRESSURE TEMPORARILY SEIZES CONTROL. LOWS IN THE 40S
TO LOWER 50S. HIGHS TUESDAY REBOUNDING INTO THE LOWER AND MIDDLE
70S.

WEDNESDAY INTO THURSDAY...A MOISTURE STARVED UPPER LEVEL SHORT WAVE
AND SURFACE COLD FRONT MOVE ACROSS THE REGION. AT THIS POINT NO
PRECIPITATION IS EXPECTED. WARMER WEDNESDAY WITH HIGHS RANGING FROM
AROUND 70 NORTH TO THE UPPER 70S SOUTHEAST. COOLER THURSDAY WITH
HIGHS RANGING FROM THE MIDDLE 60S TO LOWER 70S.

FRIDAY INTO SATURDAY...THE UPPER LEVEL RIDGE LOOKS TO NOSE EASTWARD
INTO OUR NECK OF THE WOODS...WHICH BODES WELL FOR ANOTHER WARMING
TREND SETTING IN TO ROUND OUT THE WEEK. THERE COULD BE SOME
INSTABILITY DRIVEN SHOWERS...BUT EXTENDED MODELS DISAGREE ON THE
AMOUNT OF AVAILABLE MOISTURE AS WELL AS THE STRENGTH OF A POSSIBLE
CAPPING INVERSION ALOFT SO WILL CONTINUE TO LEAVE OUT POPS AT THIS
TIME. HIGHS BOTH DAYS RANGING FROM THE LOWER AND MIDDLE 70S FAR
NORTH TO AROUND 80 SOUTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 703 AM EDT SUN SEP 1 2013

IFR STRATUS HAS BECOME FAIRLY WIDESPREAD ACROSS NE LOWER...WHILE
FOG HAS BEEN AN ISSUE AT PLN AND MBL. THE STRATUS WILL LIKELY LIFT
INTO MVFR AND FINALLY INTO VFR BY LATE MORNING. THE FOG LIKELY TO
LIFT SOONER. HIGH CLOUDS WILL STREAM IN FROM THE WEST...IN ADVANCE
OF UPPER LEVEL SHORTWAVE AND CLUSTER OF SHOWERS AND STORMS FROM NE
WISCONSIN/CENTRAL UPPER. THESE ARE NOT LIKELY TO AFFECT NW LOWER
TAF SITES. RATHER...WILL BE AWAITING A COLD FRONT THAT WILL BE
ASSOCIATED WITH A DIFFERENT DEVELOPING BAND OF SHOWERS AND STORMS
WHICH WILL LIKELY BE A SCATTERED BAND OF ACTIVITY ROLLING THROUGH.
WILL JUST TIME THIS WITH A VCTS FOR RIGHT NOW...AS THE BETTER
ACTION WILL LIKELY BE ACROSS EASTERN UPPER. APN TO GET VCTS IN THE
EVENING TONIGHT. ATMOSPHERE IS TOO CAPPED OFF FOR ANY DIURNAL LAKE
BREEZE CONVERGENCE FORCING. WINDS WILL BECOME MORE VARIABLE/LIGHT
AS THE FRONT/LOW PRESSURE SWINGS THROUGH...WITH AN ABRUPT SWITCH
TO OUT OF THE NW LATE IN THE TAF PERIOD...AND INCREASE IN SPEED.
THIS SPEED INCREASE WILL BE FELT MORE TOMORROW DURING THE DAY.


&&

.MARINE...
ISSUED AT 352 AM EDT SUN SEP 1 2013

A WEAK S/SE WIND TODAY AHEAD OF AN APPROACHING COLD FRONT...WILL
TRY AND TURN MORE ONSHORE THIS AFTERNOON DUE TO ANTICIPATED LAKE
BREEZES. THIS WILL CHANGE THROUGH THE NIGHT...AS A PERIOD OF
SCATTERED SHOWERS AND STORMS WILL BLOW THROUGH ALONG WITH THE COLD
FRONT. BEHIND THIS FRONT...WINDS WILL SHIFT ABRUPTLY OUT OF THE
NW....WHILE OVERLAKE INSTABILITY DEVELOPS AND A TIGHTER PRESSURE
GRADIENT SETTLES IN OVER THE GREAT LAKES. ADVISORY LEVEL WINDS ARE
LIKELY MONDAY AND MONDAY NIGHT IN MANY OF THE NEARSHORE WATERS.
THIS IS ESPECIALLY TRUE FOR PRESQUE ISLE LIGHT/NE LOWER MICHIGAN
NEARSHORES. HIGHER PRESSURE THEN BUILDS IN FOR QUIETER/CALMER
BOATING CONDITIONS FOR THE REMAINDER OF THE WORK WEEK.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...BA
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD








AREA FORECAST DISCUSSION

NWS GAYLORD MI

 714 AM EDT SUN SEP 1 2013

.SYNOPSIS...
ISSUED AT 352 AM EDT SUN SEP 1 2013

A COLD FRONT WILL MOVE IN FROM THE WEST TODAY...BRINGING A CHANCE
FOR SHOWERS AND THUNDERSTORMS...THOUGH TEMPERATURES WILL REMAIN
RATHER WARM. BEHIND THE FRONT...ON LABOR DAY...IT WILL FEEL MUCH
MORE LIKE AUTUMN. MAINLY DRY AND SOMEWHAT WARMER WEATHER IS EXPECTED
FOR THE REMAINDER OF THE WEEK.

&&

.UPDATE...
ISSUED AT 703 AM EDT SUN SEP 1 2013

STRATUS HAS BECOME FAIRLY WIDESPREAD COMING IN OFF LAKE
HURON...AND AIDED BY EXCELLENT COOLING OF THE BL. FOG ALSO WAS
COMMON...BUT NOT WIDESPREAD...YET DENSE IN SPOTS. STRATUS WILL
LIKELY LINGER FOR A BIT...WHILE HIGHER LEVEL CLOUDS STREAM IN FROM
THE WEST. ALSO...A CLUSTER OF SHOWERS AND STORMS WILL ROLL IN FROM
NE WISCONSIN/CENTRAL UPPER...AND LIKELY SCRAPE WESTERN SECTIONS OF
CHIP/MACK...MAYBE FAR NRN LAKE MICHIGAN. NOT TOTALLY SURE OF THE
EVOLUTION OF THIS PRECIP...AS IT SHOULD BE MORE DRIVEN BY THE H8
WESTERLY LLJ OUT TO OUR WEST. THAT SAID...UPPER LEVEL SHORTWAVE
WILL ALREADY BE THROWING SOME ENERGY IN ACROSS THESE AREAS AS
WELL. WILL START CHANCES FOR RAIN A COUPLE HOURS EARLIER...MID
MORNING FOR EASTERN UPPER.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM EDT SUN SEP 1 2013

CONDITIONS ARE SET TO CHANGE OVER THE NEXT 24-30 HRS...AS A COLD
FRONT WILL BLOW THROUGH THE REGION WITH WARM/MUGGY SUMMER WEATHER
WILL TURN MUCH COOLER AND BREEZY FOR THE START OF NEXT WORK WEEK.
MAIN ISSUE IS THE STRENGTH AND COVERAGE OF SHOWERS AND STORMS WITH
THE FRONT.

CURRENTLY...CLEARLY EVIDENT SHORTWAVE SEEN DROPPING SE ACROSS FAR
NRN MN WITH ASSOCIATED SFC LOW PRESSURE OVER THE ARROWHEAD. A COLD
FRONT EXTENDED FROM THIS LOW PRESSURE BACK ACROSS MN AND FAR FAR
NW IOWA. SHOWERS AND STORMS HAVE REALLY FALLEN APART ACROSS THE
ENTIRE FRONT...WITH LOSS OF DIURNAL HEATING. LATEST RUC ANALYSIS
SHOWING PRESENCE OF AN ELEVATED WARM FRONT WITH 30-35KTS OF A
WESTERLY JET...WARM/MOIST CONVERGENCE PIN-POINTED ON EASTERN
UPPER. SKIES WERE CLEAR HOWEVER...WITH ONLY SOME THIN HIGH LEVEL
CLOUDS IN EASTERN UPPER FROM EARLIER SHOWERS AND STORMS ACROSS
WISCONSIN. THESE CLOUDS AND EVEN PRECIP HAD PROBLEMS HOLDING
TOGETHER AS THEY WORKED THEIR WAY WEST INTO RELATIVELY DRIER AIR
MASS CENTERED RIGHT OVER NRN MICHIGAN. DID SEE A FEW LIGHT RAIN
SHOWERS/SPRINKLES DOTTING EASTERN UPPER...OTHERWISE...THERE WAS
ABSOLUTELY NO PRECIP NEAR NRN MICHIGAN. THE MAIN ACTION WAS STUCK
ACROSS IOWA IN BETTER LOW LEVEL CONVERGENCE AND INSTABILITY. A
MUGGY SFC AIR MASS AND THE CLEAR SKIES HAS RESULTED IN PATCHY
AREAS OF FOG THAT HAS BEEN LOCALLY DENSE. TEMPERATURES IN UPPER
50S TO LOWER HALF OF THE 60S FOR MOST.

TODAY AND TONIGHT...SOME ADDITIONAL UPSTREAM HIGH LEVEL CLOUDS
WILL SWEEP IN OVER THE AREA 09-12Z...ESPECIALLY EASTERN
UPPER...BUT WILL LIKELY STILL HAVE A HARD TIME NOT THINNING EVEN
MORE. THUS...BELIEVE THE SKY COVER WILL BE RATHER CLEAR FOR ALL TO
START THE DAY. CHANCES FOR PRECIPITATION WERE REMOVED THROUGH 15Z
BASED ON THE AFOREMENTIONED. A DECENT WARMING PERIOD WILL GET
TEMPERATURES IN THE UPPER 70S NORTH...TO THE LOWER HALF OF THE 80S
IN NRN LOWER TODAY. WINDS WILL BE LIGHT OUT OF THE S/SE...THUS
LIGHT WINDS. THESE WINDS WILL TRY AND TURN ONSHORE AS WE HEAD
THROUGH THE AFTERNOON...CREATING A POCKET OF BETTER LOW LEVEL
CONVERGENCE ACROSS PORTIONS OF NE LOWER. AS THE FRONT NEARS THE
WESTERN CWA LATE THIS AFTERNOON...AND CROSSES NE LOWER AFTER THE
EVENING...WEAK H8-H7 WAA...DPVA AND H4-H2 UPPER DIVERGENCE IN
LEFT EXIT REGION OF AN UPPER JETLET...WILL COMBINE WITH DIURNAL
HEATING/DESTABILIZATION FOR A CHANCE AT SHOWERS AND STORMS.
PROBLEMS...UPPER WAVE STARTS TO LIFT NE AND SHEAR OF THE MEAGER
CORRIDOR OF DEEPER MOISTURE. PLUS...CAPPING AROUND 800MB AND LACK
OF ANY APPRECIABLE LL MOISTURE SHOWS QUITE A BIT OF CINH (40J/KG)
FOR MUCH OF THE DAY. THIS CAPPING DOES GET ERODED...BUT NOT UNTIL
THE FRONT ARRIVES. THIS WILL LEAVE A PERIOD OF POSSIBLE SHOWERS
AND STORMS...WHICH WILL MORE LIKELY LAST FOR 3-5 HRS ON/NEAR THE
FRONT. WIND FIELDS NOT OVERLY IMPRESSIVE WITH 0-6KM BULK SHEAR AT
30KTS...AND WET BULBS AT 11KFT ARE KIND OF HIGH. HOWEVER...DECENT
HEATING TO START THE DAY...MLCAPE OF 1500 J/KG POSSIBLE...THEN A
LOW END THREAT FOR DAMAGING WINDS AND ISOLATED LARGE HAIL WITH EH
STRONGER CELLS ARE POSSIBLE. WE ARE NOT IN A SLIGHT RISK RIGHT
NOW...AND THIS WOULD CERTAINLY NOT BE A WIDESPREAD SEVERE THREAT.
THE FRONT CROSSES NE LOWER BY MIDNIGHT...WITH A GRADUALLY
INCREASING/STRENGTHENING PRESSURE GRADIENT RESULTING IN A GROWING
COLD ADVECTION REGIME WITH BREEZIER WINDS TOWARD
DAYBREAK...ESPECIALLY DOWNWIND OF LAKE MICHIGAN AND WHITEFISH BAY.
LOW TEMPS TO FALL INTO THE 50S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 352 AM EDT SUN SEP 1 2013

INCREASING RIDGING TO START THE PERIOD TUESDAY WHICH HOLDS THROUGH
MUCH OF WEDNESDAY. THE RIDGE THEN GETS TEMPORARILY KNOCKED DOWN
LATER WEDNESDAY INTO WEDNESDAY NIGHT AS A MOISTURE STARVED SHORT
WAVE MOVES THROUGH THE FLOW. RIDGING THEN TAKES OVER ONCE AGAIN LATE
IN THE WEEK INTO THE FIRST HALF OF NEXT WEEKEND AHEAD OF THE NEXT
TROUGH. OVERALL DRY WEATHER IS EXPECTED...THOUGH THERE MAY END UP
BEING SLIGHT CHANCES FOR SHOWERS LATE IN THE WEEK. THE MAIN LONG
TERM FORECAST CONCERNS CENTER AROUND CLOUD COVER AND HIGH
TEMPERATURES MONDAY THEN POPS TO END THE PERIOD.

LABOR DAY...SHARPLY COOLER CONDITIONS ARE EXPECTED. MODEL SOUNDINGS
AND CROSS SECTIONS SHOW A DECENT AMOUNT OF MOISTURE AT LOWER LEVELS.
THIS SHOULD RESULT IN LOTS OF CLOUDS AND POSSIBLE DRIZZLE ACROSS
NORTHERN AREAS AS AN UPPER LEVEL TROUGH MOVES BY TO OUR NORTHEAST.
ACROSS SOUTHERN ZONES...THERE COULD END UP BEING A BIT LESS CLOUD
COVER WHICH MAY TEMPER TEMPERATURES. HIGHS ONLY RANGING FROM THE
LOWER 60S NORTH TO AROUND 70 SOUTHEAST.

MONDAY NIGHT THROUGH TUESDAY NIGHT...SEASONABLE WEATHER IS EXPECTED
AS SURFACE HIGH PRESSURE TEMPORARILY SEIZES CONTROL. LOWS IN THE 40S
TO LOWER 50S. HIGHS TUESDAY REBOUNDING INTO THE LOWER AND MIDDLE
70S.

WEDNESDAY INTO THURSDAY...A MOISTURE STARVED UPPER LEVEL SHORT WAVE
AND SURFACE COLD FRONT MOVE ACROSS THE REGION. AT THIS POINT NO
PRECIPITATION IS EXPECTED. WARMER WEDNESDAY WITH HIGHS RANGING FROM
AROUND 70 NORTH TO THE UPPER 70S SOUTHEAST. COOLER THURSDAY WITH
HIGHS RANGING FROM THE MIDDLE 60S TO LOWER 70S.

FRIDAY INTO SATURDAY...THE UPPER LEVEL RIDGE LOOKS TO NOSE EASTWARD
INTO OUR NECK OF THE WOODS...WHICH BODES WELL FOR ANOTHER WARMING
TREND SETTING IN TO ROUND OUT THE WEEK. THERE COULD BE SOME
INSTABILITY DRIVEN SHOWERS...BUT EXTENDED MODELS DISAGREE ON THE
AMOUNT OF AVAILABLE MOISTURE AS WELL AS THE STRENGTH OF A POSSIBLE
CAPPING INVERSION ALOFT SO WILL CONTINUE TO LEAVE OUT POPS AT THIS
TIME. HIGHS BOTH DAYS RANGING FROM THE LOWER AND MIDDLE 70S FAR
NORTH TO AROUND 80 SOUTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 703 AM EDT SUN SEP 1 2013

IFR STRATUS HAS BECOME FAIRLY WIDESPREAD ACROSS NE LOWER...WHILE
FOG HAS BEEN AN ISSUE AT PLN AND MBL. THE STRATUS WILL LIKELY LIFT
INTO MVFR AND FINALLY INTO VFR BY LATE MORNING. THE FOG LIKELY TO
LIFT SOONER. HIGH CLOUDS WILL STREAM IN FROM THE WEST...IN ADVANCE
OF UPPER LEVEL SHORTWAVE AND CLUSTER OF SHOWERS AND STORMS FROM NE
WISCONSIN/CENTRAL UPPER. THESE ARE NOT LIKELY TO AFFECT NW LOWER
TAF SITES. RATHER...WILL BE AWAITING A COLD FRONT THAT WILL BE
ASSOCIATED WITH A DIFFERENT DEVELOPING BAND OF SHOWERS AND STORMS
WHICH WILL LIKELY BE A SCATTERED BAND OF ACTIVITY ROLLING THROUGH.
WILL JUST TIME THIS WITH A VCTS FOR RIGHT NOW...AS THE BETTER
ACTION WILL LIKELY BE ACROSS EASTERN UPPER. APN TO GET VCTS IN THE
EVENING TONIGHT. ATMOSPHERE IS TOO CAPPED OFF FOR ANY DIURNAL LAKE
BREEZE CONVERGENCE FORCING. WINDS WILL BECOME MORE VARIABLE/LIGHT
AS THE FRONT/LOW PRESSURE SWINGS THROUGH...WITH AN ABRUPT SWITCH
TO OUT OF THE NW LATE IN THE TAF PERIOD...AND INCREASE IN SPEED.
THIS SPEED INCREASE WILL BE FELT MORE TOMORROW DURING THE DAY.

&&

.MARINE...
ISSUED AT 352 AM EDT SUN SEP 1 2013

A WEAK S/SE WIND TODAY AHEAD OF AN APPROACHING COLD FRONT...WILL
TRY AND TURN MORE ONSHORE THIS AFTERNOON DUE TO ANTICIPATED LAKE
BREEZES. THIS WILL CHANGE THROUGH THE NIGHT...AS A PERIOD OF
SCATTERED SHOWERS AND STORMS WILL BLOW THROUGH ALONG WITH THE COLD
FRONT. BEHIND THIS FRONT...WINDS WILL SHIFT ABRUPTLY OUT OF THE
NW....WHILE OVERLAKE INSTABILITY DEVELOPS AND A TIGHTER PRESSURE
GRADIENT SETTLES IN OVER THE GREAT LAKES. ADVISORY LEVEL WINDS ARE
LIKELY MONDAY AND MONDAY NIGHT IN MANY OF THE NEARSHORE WATERS.
THIS IS ESPECIALLY TRUE FOR PRESQUE ISLE LIGHT/NE LOWER MICHIGAN
NEARSHORES. HIGHER PRESSURE THEN BUILDS IN FOR QUIETER/CALMER
BOATING CONDITIONS FOR THE REMAINDER OF THE WORK WEEK.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.

&&

$$

UPDATE...SD
SYNOPSIS...AS
SHORT TERM...SD
LONG TERM...AS
AVIATION...SD
MARINE...SD







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 152 AM EDT SUN SEP 1 2013

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 359 PM EDT SAT AUG 31 2013

MAIN FCST CONCERNS IN THE SHORT TERM INVOLVE SHRA/TS CHCS ASSOCIATED
WITH SHRTWV NOW NEAR LK WINNIPEG.

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE NRN CONUS ON THE NRN FLANK OF SPRAWLING HI PRES CENTERED OVER
THE SW CONUS. STUBBORN LO CLDS OVER THE SCENTRAL COUNTIES ARE
FINALLY BURNING OFF. THERE IS A SHRTWV TRACKING THRU ONTARIO...BUT
THIS DISTURBANCE IS PASSING FAR ENUF TO THE N THAT THE COMMA TAIL
-SHRA ARE JUST BRUSHING NEAR ISLE ROYALE. WEAK RDG OF HI PRES OVER
THE GRT LKS/SHARP SUBSIDENCE INVRN SHOWN ON LOCAL 12Z RAOBS IS
BRINGING QUIET WX TO THE CWA FOR NOW. A STRONGER SHRTWV IS PRESENT
ALONG THE NDAKOTA/CNDN BORDER AND MOVING QUICKLY TO THE ESE. WHERE
THE SHARP DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
OVERSPREADING AXIS OF HIER MUCAPE/H85 THETA E AHEAD OF ATTENDANT
COLD FNT...NMRS SHRA/TS ARE BREAKING OUT IN MN.

TNGT...SHRTWV JUST SW OF LK WINNIPEG IS PROGGED TO MOVE ESE AND OVER
NCENTRAL LK SUP BY 12Z SUN. AS THE DPVA/DEEP LYR QVECTOR CNVGC AND
AXIS OF HIER INSTABILITY/H85 THETA E MOVE INTO WRN LK SUP THIS
EVNG...EXPECT SHRA/TS NOW OVER MN TO SHIFT INTO THE WRN LAND CWA BY
06Z. GIVEN FCST MUCAPE IN EXCESS OF 1000 J/KG...SFC-6KM SHEAR IN THE
40-50KT RANGE /FORTUNATELY THE STORMS WL BECOME ELEVATED SO THIS WL
NOT BE THE EFFECTIVE LYR SHEAR/...AND FAIRLY SHARP LLVL CNVGC ALONG
ATTENDANT COLD FNT...SOME OF THESE STORMS MAY BE STRONG. BUT WITH
LOSS OF DAYTIME HEATING AND WEAKENING H85 THETA E AXIS...EXPECT THE
INTENSITY OF THESE SHRA/TS TO DIMINISH AS THEY SPREAD INTO CENTRAL
UPR MI LATE. IN FACT...THE MOST RECENT SPC CONVECTIVE OUTLOOK THRU
12Z SUN CONFINES THE SLGT RISK FOR SVR TS TO MN AND FAR WRN LK SUP.
WHERE TEMPS HAVE A CHC TO COOL DOWN A BIT OVER THE E HALF BEFORE THE
ARRIVAL OF CLDS/A BIT SHARPER PRES GRADIENT...ADDED PATCHY FOG WITH
EXPECTATION THAT MIN TEMPS FALLING INTO THE UPR 50S WL FALL THRU THE
CROSSOVER DEWPT OBSVD THIS AFTN.

SUN...AS SHRTWV OVER NCENTRAL LK SUP IN THE MRNG SHIFTS INTO SE
ONTARIO IN THE AFTN...DNVA/DEEP LYR QVECTOR DVGC/VIGOROUS NEGATIVE
H85 THETA E ADVCTN IS FCST TO ARRIVE W-E FOLLOWING ATTENDANT COLD
FROPA. EXPECT BAND OF SHRA/TS AHD OF COLD FNT TO SHIFT FM THE CNTRL
ZNS INTO THE ERN ZNS DURING THE MRNG. SHRA/TS INTENSITY MAY PICK UP
OVER THE FAR ERN CWA IN THE EARLY AFTN WITH IMPACT OF DAYTIME
HEATING LIFTING MUCAPE TO 500-1000 J/KG AND DEEP LYR SHEAR 30 TO 40
KTS BEFORE THE MORE ROBUST QVECTOR DVGC ARRIVES IN THE AFTN AND
BEGINS TO SUPPRESS THE CONVECTION WITH STRENGTHENING INVRN FOLLOWING
COLD FROPA AT ERY NEAR 21Z. THIS THREAT WOULD BE GREATER IF THE
SOMEWHAT SLOWER GFS VERIFIES...BUT THE PRESENT STEADY SPEED OF
SHRTWV INDICATES THE FASTER MODEL FCSTS ARE ON THE RIGHT TRACK.
FOLLOWING THE COLD FROPA AND ARRIVAL OF LLVL COOLER AIR...NAM FCST
SDNGS SHOW SHARPENING LLVL INVRN/PROSPECT FOR LO CLDS AND SOME
SPRINKLES...ESPECIALLY OVER THE W AND NCENTRAL WITH UPSLOPE NW FLOW.
SFC TEMPS MAY ACTUALLY FALL AT THESE PLACES DURING THE AFTN.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 359 PM EDT SAT AUG 31 2013

MORE SEASONABLE WEATHER IS EXPECTED THROUGH MUCH OF THE UPCOMING
WEEK...WITH CHANCES OF PRECIPITATION MONDAY AND AGAIN WEDNESDAY.

SUNDAY NIGHT AND MONDAY...A STRONG AND SHARP MID-LEVEL SHORTWAVE
OVER NE LAKE SUPERIOR WILL BE STARTING TO EXIT TO THE EAST AT THE
START OF THE PERIOD. THE ASSOCIATED SFC LOW WILL ALSO BE TRACKING
EASTWARD AWAY FROM EASTERN LAKE SUPERIOR. THE MAIN FORECAST CONCERN
IS HOW LONG MOISTURE WILL LINGER BEHIND THIS SYSTEM...AND HOW
WIDESPREAD UPSLOPE DRIZZLE/SHOWERS WILL BE. WITH PLENTY OF LOW-LEVEL
MOISTURE WRAPPING BEHIND THE LOW...EXPECT PLENTY OF DRIZZLE AND
LIGHT SHOWERS FOR ANY AREA EXPOSED TO NNW WINDS OFF LAKE SUPERIOR.
SUBSIDENCE WILL LOWER INVERSION HEIGHTS TO AROUND 1KM ACROSS THE
AREA...SO THE SATURATED LAYER WILL BE QUITE SHALLOW. INSOLATION ON
MONDAY SHOULD BE STRONG ENOUGH TO START ERODING THIS MOIST LAYER
MONDAY MORNING. INCREASINGLY DRIER AIR ADVECTING IN FROM WESTERN
ONTARIO SHOULD THEN REMOVE REMAINING CLOUDS/PRECIP FROM WEST TO EAST
THROUGHOUT MONDAY AFTERNOON.

HAVE INCREASED WINDS SEVERAL KNOTS ACROSS THE EAST HALF OF THE CWA
GIVEN A 1020MB SFC HIGH IN THE UPPER MS VALLEY IMPINGING ON THE
BACKSIDE OF THE DEPARTING 1002MB LOW. COULD SEE QUITE A BREEZY DAY
FOR MUCH OF THE AREA...WITH WINDS GUSTING OVER 30MPH RIGHT NEAR THE
LAKE SUPERIOR SHORE FROM BIG BAY EASTWARD. WILL CONTINUE TO RAMP UP
WORDING ON A HIGH SWIM RISK GIVEN THE LABOR DAY HOLIDAY.

MONDAY NIGHT...AS THE SFC HIGH SETTLES OVER NORTHERN WI MONDAY
NIGHT...CLEAR SKIES AND LOW PWAT VALUES OF LESS THAN 0.5 INCHES WILL
ALLOW FOR GOOD RADIATIONAL COOLING. HAVE MAINTAINED PREVIOUS
FORECAST TEMPS OF LOW 40S INTERIOR WEST HALF TO LOW 50S NEAR THE
GREAT LAKES. RESIDUAL STRONGER NW GRADIENT FLOW ACROSS THE EAST HALF
SHOULD LIMIT COOLING TO SOME EXTENT.

TUESDAY THROUGH THURSDAY...A SHORTWAVE TROUGH CURRENTLY TRACKING
EASTWARD ALONG THE ALLUETIAN ISLANDS WILL STALL OVER WESTERN ALASKA
AND SEND A SERIES OF WEAK WAVES ACROSS WESTERN CANADA. THE MAIN WAVE
OF INTEREST WILL BECOME AMPLIFIED BY ANOTHER STRONGER WAVE OVER THE
NORTH SLOPE OF ALAKSA. TIMING AND STRENGTH OF THIS FEATURE HAVE BEEN
UNDERSTANDABLY DIFFICULT FOR THE MODELS TO PIN DOWN. THE GFS HAS
WAVERED IN STRENGTH OVER THE LAST SEVERAL RUNS...WITH THE LATEST TWO
RUNS INDICATING A SLOWER AND WETTER SOLUTION. THIS IS LIKELY A
RESULT OF A LONGER PRECEEDING PERIOD OF LOW-LEVEL MOISTURE RETURN.
THE GEM IS THE QUICKEST SOLUTION OF THE THREE. HAVE OPTED TO EMPLOY
THE ECMWF FOR THE REST OF THE FORECAST GIVEN ITS MIDDLE GROUND AND
CONTINUITY OVER THE LAST COUPLE DAYS.

THE MAIN MID-LEVEL AND SFC LOWS WILL TRACK WELL NORTH OF THE
CWA...POSSIBLY AS FAR NORTH AS SOUTHERN HUDSON BAY. THE 990MB SFC
LOW DEPICTED BY THE ECMWF WILL BE STRONG ENOUGH TO SEND A POTENT
COLD FRONT SSE-WARD ACROSS THE CWA WEDNESDAY MORNING.
HOWEVER...THERE WILL BE A SUBSTANTIAL AMOUNT OF DRY AIR WITH THIS
SYSTEM GIVEN ITS ORIGIN. WILL PLACE ONLY SLIGHT CHANCE POPS ACROSS
THE FAR NORTH AND EAST CLOSER TO THE STRONGEST FORCING VIA MID-LEVEL
Q-VECTOR CONVERGENCE AND THE LEFT EXIT OF A 120KT UPPER JET. MUCH OF
UPPER MI...ESPECIALLY THE SOUTHWEST...LOOKS TO BE UNDER SUBSIDENCE
FROM THE RIGHT ENTRANCE OF THE JET...AND MAY NOT EVEN SEE MUCH IN
THE WAY OF CLOUD COVER. MOST OF THE COOLER AIR BEHIND THE FRONT WILL
STAY EAST OF THE AREA...SO ONLY A SLIGHTLY COOLER DAY THAN WEDNESDAY
IS EXPECTED FOR THURSDAY.

FRIDAY AND SATURDAY...BESIDE DEVELOPING THE IDEA OF DEEPER TROUGHING
ACROSS EASTERN CANADA...MODEL AGREEMENT ON SMALLER SCALE FEATURES IS
POOR BY THIS POINT IN THE FORECAST. THE GFS/GEM INDICATE STRONG SFC
HIGH PRESSURE BUILDING ACROSS THE AREA...WHILE THE ECMWF KEEP THE
HIGH MUCH FARTHER NE NEAR JAMES BAY. A WEAK SHORTWAVE DEPICTED BY
BOTH THE ECMWF AND GFS COULD BRING SHOWER CHANCES FOR FRIDAY...BUT
TIMING THE GFS IS SOMEWHAT SLOWER WITH THIS IDEA. EITHER WAY...VERY
LIMITED MOISTURE WILL PRECLUDE ANYTHING MORE THAN SPOTTY SHOWER
COVERAGE. HAVE OPTED TO MAINTAIN CONCENSUS FORECAST AT THIS POINT
GIVEN UNCERTAINTY.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 151 AM EDT SUN SEP 1 2013

STRONG DISTURBANCE AND ASSOCIATED SFC LOW AND COLD FRONT WILL AFFECT
THE REGION THRU THIS FCST PERIOD. ALTHOUGH SHRA/TSRA HAVE DIMINISHED
IN COVERAGE OVER THE LAST SEVERAL HRS...STRENGTH OF DISTURBANCE
SUGGESTS THERE WILL BE SHRA AND A FEW TSRA SCATTERED AROUND THE AREA
THRU THE NIGHT INTO THE MORNING HRS. UNLESS MORE ORGANIZED PCPN
DEVELOPS...ONLY VCSH WILL BE UTILIZED AT KIWD/KCMX/KSAW OVERNIGHT.
VFR CONDITIONS SHOULD GENERALLY PREVAIL...EXCEPT AT KCMX WHERE SOME
BR HAS DEVELOPED WITH LIGHT UPSLOPE. NOT OUT OF THE QUESTION THAT
IFR OR EVEN LIFR COULD DEVELOP THERE. AS WINDS VEER THEN SHIFT TO
GUSTY NW WITH PASSAGE OF COLD FRONT...EXPECT CONDITIONS TO
DETERIORATE TO IFR AT KIWD/KCMX THIS MORNING. LATER FRONTAL PASSAGE
AND INITIALLY POST FRONTAL DOWNSLOPE NW WINDS SHOULD RESULT IN ONLY
MVFR CIGS AT KSAW MID/LATE AFTN. WITH LATER FRONTAL PASSAGE...IT`S
POSSIBLE TSRA COULD AFFECT KSAW EARLY IN THE AFTN. MVFR CIGS SHOULD
PREVAIL AT ALL TERMINALS INTO THE EVENING HRS.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT SAT AUG 31 2013

EXPECT SSW WINDS UP TO 20-25 KTS TONIGHT INTO SUN MORNING OVER THE E
HALF OF THE LAKE UNDER A SHARPENING PRES GRADIENT AHEAD OF AN
APPROACHING COLD FRONT. FOLLOWING THE PASSAGE OF THIS FRONT...THERE
WILL BE A WIND SHIFT TO THE NW...WITH WINDS INCREASING UP TO 25 KTS
IN THE AFTERNOON. THE COMBINATION OF DECREASING STABILITY WITH THE
ARRIVAL OF A COOL AIRMASS AND A SHARPENING PRES GRADIENT BETWEEN A
DEPARTING LO PRES SYSTEM AND AN APPROACHING HI WILL RESULT IN NW-N
WINDS UP TO 20-30 KTS ON SUN NIGHT INTO MON. THE ARRIVAL OF THE HI
AND WEAKER PRES GRADIENT WILL ALLOW WINDS TO DIMINISH UNDER 20 KTS
TUE THRU THU.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...ROLFSON
MARINE...KC







AREA FORECAST DISCUSSION

NWS ELKO NV

 200 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.

&&

.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 11 PM PDT THIS EVENING FOR NORTHEASTERN
NYE COUNTY...NORTHWESTERN NYE COUNTY...SOUTHERN LANDER COUNTY
AND SOUTHERN EUREKA COUNTY...WHITE PINE COUNTY.

&&

$$

99/87/87/99






AREA FORECAST DISCUSSION

NWS LAS VEGAS NV

 957 AM PDT SUN SEP 1 2013

.SYNOPSIS...MOIST AND UNSTABLE AIR WILL ONCE AGAIN RESULT ON SHOWERS
AND THUNDERSTORMS ACROSS THE AREA THROUGH THIS EVENING ESPECIALLY
ACROSS SOUTHERN NEVADA...NORTHWEST ARIZONA AND THE HIGHER ELEVATIONS
OF INYO COUNTY. THE PRIMARY THREAT WITH STORMS TODAY WILL ONCE AGAIN
BE LOCALLY HEAVY RAIN THAT COULD RESULT IN FLASH FLOODING. ALTHOUGH
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THROUGH THE
END OF THE WEEK...THE BEST CHANCES SHOULD BE NORTH AND EAST OF LAS
VEGAS. HIGH TEMPERATURES SHOULD GRADUALLY RETURN TO NEAR NORMAL
LEVELS BY THE MIDDLE OF THE WEEK.
&&

.UPDATE...MAIN CONCERN FOR TODAY IS WHETHER TO EXPAND THE FLASH
FLOOD WATCH INTO DEATH VALLEY NATIONAL PARK. WATER VAPOR LOOP SHOWED
MID LEVEL MOISTURE GRADIENT SURGING NORTH...POSSIBLY FOCUSING STORMS
FARTHER NORTH THAN DVNP LATER IN THE DAY. CONFIDENCE IS NOT HIGH
ENOUGH TO JUSTIFY EXPANSION...SO WILL STAND PAT FOR NOW. NO CHANGES
AT THIS TIME.
&&

.PREVIOUS DISCUSSION...
ISSUED AT 304 AM PDT SUN SEP 1 2013

.SHORT TERM...CONVECTION HAS REFUSED TO GO AWAY TONIGHT ACROSS
MOHAVE, SOUTHERN CLARK AND NORTHEAST SAN BERNARDINO COUNTIES AS
ACTIVITY THAT DEVELOPED EARLIER BEHIND AN OUTFLOW BOUNDARY THAT
PUSHED SOUTH ACROSS THE AREA BLOSSOMED AND HAS MANAGED TO DUMP SOME
HEFTY AMOUNTS OF RAIN. ONE AUTOMATED RAIN GAUGE NEAR SEARCHLIGHT HAS
MEASURED 2.60 INCHES OF RAIN IN ABOUT 2 HOURS AND VERY HEAVY RAIN
WAS FALLING AROUND YUCCA AND OTHER AREAS IN SOUTH-CENTRAL MOHAVE
COUNTY. CLOUD TOPS HAVE ACTUALLY COOLED IN THE LAST HOUR OR SO WITH
THIS CONVECTIVE COMPLEX WITH VALUES PUSHING -72C WHICH IS IMPRESSIVE
FOR ANYTIME OF DAY BUT ESPECIALLY AT THIS HOUR OF THE NIGHT. THIS
CONVECTIVE COMPLEX OVER MOHAVE COUNTY WILL BE THE MAIN ISSUE WITH
THE INITIAL PORTIONS OF THE FORECAST AS IT MAY WORK OVER ENOUGH OF
THE SOUTHEAST PORTIONS OF THE AREA TO INHIBIT CONVECTION UNTIL LATER
TODAY OR EVEN POSSIBLY ALTOGETHER. ELSEWHERE THINGS HAVE RELATIVELY
CALMED DOWN AND CLOUD COVER HAS CLEARED OUT ESPECIALLY ACROSS MUCH
OF THE NORTHWEST CWFA.

FOR TODAY, THE FLOW ALOFT WILL START TO TAKE ON MORE OF A SOUTHWEST
COMPONENT ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE CWFA. WHILE
THIS WILL TRY TO BRING IN SOME DRIER AIR, THERE IS SO MUCH MOISTURE
IN PLACE, ALONG WITH SUFFICIENT INSTABILITY, THAT IT IS HARD TO
DISCOUNT THUNDERSTORMS DEVELOPING ANYWHERE FROM LATE THIS MORNING
INTO THIS AFTERNOON AND EVENING. HOWEVER, LOOKING AT 700-300 MB
THETA E VALUES THERE IS A NOTICEABLE INCREASE IN VALUES ABOVE 340K
ACROSS LINCOLN, CLARK AND NORTHERN MOHAVE COUNTIES WHICH ALSO
MATCHES WHERE THE BEST COMPUTED CAPE VALUES ARE SHOWN. SO, WE HAVE
CONTINUED WITH THE HIGHEST POPS ACROSS THESE AREAS. IN ADDITION, A
WEAK RIPPLE IN THE MID-LEVELS (A WEAK INVERTED TROUGH) AND A
POTENTIAL ASSOCIATED PIECE OF ENERGY ARE SHOWN TO LIFT NORTHEAST
ACROSS SOUTHERN NEVADA LATE THIS AFTERNOON INTO THIS EVENING WHICH
MAY FURTHER HELP TO ENHANCE CONVECTION IN THESE AREAS AND COULD EVEN
KEEP IT GOING LATER THIS EVENING AND INTO LATE TONIGHT THAN WHAT WE
SEE GO ON ELSEWHERE. WITH THAT, I WENT AHEAD AND ADJUSTED UP POPS
FOR LINCOLN AND NORTHERN MOHAVE COUNTIES INTO THE LATER PORTIONS OF
TONIGHT. THE FLASH FLOOD WATCH WAS EXTENDED FOR THESE AREAS LAST
EVENING FOR THE ONGOING CONVECTION, SO EVEN THOUGH MODELS SHOW
THINGS NOT GETTING GOING UNTIL BETWEEN 10 AM AND NOON, IT WILL
REMAIN OUT. THE STEERING FLOW TODAY WILL BE STRONGER AND MORE WELL
DEFINED FROM THE SOUTHWEST THAN THE ZIG-ZAG NATURE WE HAD YESTERDAY,
AND THUS WE WILL NEED TO WATCH IN THE LAS VEGAS VALLEY FOR ACTIVITY
TO MOVE IN FROM THE SPRING MOUNTAINS BY LATE THIS MORNING AND INTO
THIS AFTERNOON. THIS COULD PRESENT PROBLEMS WITH THE CARPENTER 1
FIRE BURN AREA AND WE WILL NEED TO WATCH OUT AGAIN FOR DEBRIS FLOWS.

ELSEWHERE, BOTH THE GFS AND ECMWF AS WELL AS THE HRRR MODEL SUGGEST
THAT ACTIVITY SHOULD GET GOING ACROSS THE SOUTHERN SIERRA, WHITE
MOUNTAINS AS WELL AS MOUNTAINS OF ESMERALDA AND CENTRAL NYE
COUNTIES. ENOUGH INSTABILITY AND CAPE ARE SHOWN THERE AS IS MOISTURE
TO JUSTIFY ADDING THESE AREAS TO THE FLASH FLOOD WATCH, HOWEVER
SINCE ACTIVITY WILL LIKELY TAKE UNTIL LATER THIS MORNING, THE WATCH
WILL START HERE AT 11 AM. AGAIN, THE STEERING FLOW WILL BE FROM THE
SOUTHWEST WHICH COULD DRIVE STORMS THAT DEVELOP ALONG THE SOUTHERN
SIERRA CREST INTO THE OWENS VALLEY LATER THIS AFTERNOON AND THIS
EVENING. WE MAY GET A LITTLE MORE ISSUES WITH WIND HERE AS THERE
WILL BE A LITTLE MORE LOWER LEVEL DRYING THAT TAKES PLACE AND STORMS
MAY GET SOME MOMENTUM AS THEY DROP OFF THE MOUNTAINS AND INTO THE
VALLEYS AND THE AIR ACCELERATES DOWN THE TERRAIN.

TEMPS TODAY SHOULD BE A FEW DEGREES WARMER THAN SATURDAY, EXCEPT
WHERE CLOUDS ARE THICKER AND CONVECTION DEVELOPS EARLIER.

FOR LABOR DAY, THE TROUGH APPROACHING NORCAL WILL KEEP THE FLOW
ALOFT SOUTHWEST TO SOUTH. EVEN THOUGH A LITTLE DRYING TAKES PLACE
ACROSS SOUTHEAST CALIFORNIA, THERE IS STILL ENOUGH MOISTURE AND
INSTABILITY TO KEEP THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
AROUND EVERYWHERE. HOWEVER, THE BEST MOISTURE REMAINS NORTH AND EAST
OF LAS VEGAS, WHICH IS WHERE THE HIGHEST POPS WERE PLACED. HOWEVER,
IT DOES APPEAR THAT THE COVERAGE OF STORMS WILL BE AS GREAT AS WHAT
WE COULD SEE TODAY. WITH A LESS IN THE WAY OF STORMS, THERE COULD BE
MORE SUN AND THUS TEMPS SHOULD BE A LITTLE WARMER.

ONE THING TO WATCH TODAY AND MONDAY WILL BE HOW MUCH ACTIVITY GETS
GOING ON THE MOIST-DRY INTERFACE AS THIS AREA MAY BE MORE ACTIVE
THAN WHAT THE MODELS SHOW. TODAY MAY HELP PROVIDE SOME CLUES AS TO
WHAT WE COULD SEE ALONG THAT INTERFACE TOMORROW.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...HIGH PRESSURE WILL
PERSIST ROUGHLY NEAR THE FOUR CORNERS AREA MONDAY NIGHT THROUGH
FRIDAY WITH GENERALLY A SOUTHERLY FLOW OVER THE FORECAST AREA. THIS
WILL KEEP MONSOON MOISTURE IN PLACE WITH ISOLATED TO SCATTERED
THUNDERSTORMS EACH DAY. THE GFS AND ECMWF ARE IN FAIR AGREEMENT FOR
A BIT OF A PATTERN CHANGE BY SATURDAY WITH A LOW PRESSURE SYSTEM
FINALLY MOVING EAST THROUGH THE PACIFIC NORTHWEST. THE RESULT IS A
WEST TO MAYBE EVEN NORTHWEST FLOW OVER THE NORTHERN PART OF THE
FORECAST AREA BRINGING IN DRIER AIR. THIS MAY BRING AN END TO THE
THUNDERSTORM CHANCES FOR THE FAR NORTH AND PARTS OF THE WESTERN CWA.
GUIDANCE CONTINUES TO INDICATE TEMPERATURES A TOUCH ABOVE NORMAL FOR
MOST OF THE LONG TERM.

.AVIATION...FOR MCCARRAN...WINDS WILL FAVOR TYPICAL DIURNAL TRENDS
AWAY FROM ANY SHRA/TSRA THROUGH TONIGHT. SCT-BKN CLOUDS AOA 10-15K
FEET ARE EXPECTED THROUGH TONIGHT. SHRA/TSRA ARE EXPECTED TO DEVELOP
IN AND AROUND THE LAS VEGAS VALLEY AND IN THE APPROACH CORRIDORS ON
TODAY AFTER 18Z AND DIMINISH BETWEEN 04Z AND 07Z MONDAY. GUSTY AND
ERRATIC WINDS...REDUCED CIGS AND VSBY ARE POSSIBLE IN AND NEAR ANY
SHRA/TSRA AND OUTFLOW BOUNDARIES WHICH MAY IMPACT CONFIGURATIONS.
THE FLOW IN THE ATMOSPHERE IS FROM THE SOUTHWEST TO WEST THROUGH
TONIGHT WHICH WOULD FAVOR PUSHING SHRA/TSRA IN FROM THE SPRING
MOUNTAINS TOWARD THE AIRPORT COMPLEX.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...EXPECT SCT-BKN CLOUDS AOA 10-15K FEET WITH WINDS
FAVORING TYPICAL DIURNAL TRENDS THROUGH TONIGHT AWAY FROM ANY
SHRA/TSRA. REDUCED CIGS AND VSBY AND GUSTY AND ERRATIC WINDS IN AND
NEAR SHRA/TSRA WILL BE THE MAIN THREATS. SHRA AND TSRA ARE EXPECTED
AFTER 18Z SUNDAY BEFORE DECREASING AROUND 06Z MONDAY WITH ACTIVITY
MOST LIKELY IN LINCOLN, CLARK, ESMERALDA, MOHAVE, CENTRAL NYE AND
WESTERN INYO COUNTIES. SHRA/TSRA SHOULD MAINLY FROM EAST THROUGH
TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NVZ015-016-018>022.
     FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR NVZ014.
AZ...FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ001>003-036.
CA...FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR CAZ519>521.
&&

$$

MORGAN/STACHELSKI/HARRISON

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER







AREA FORECAST DISCUSSION

NWS LAS VEGAS NV

 414 AM PDT SUN SEP 1 2013

.SYNOPSIS...MOIST AND UNSTABLE AIR WILL ONCE AGAIN RESULT ON SHOWERS
AND THUNDERSTORMS ACROSS THE AREA THROUGH THIS EVENING ESPECIALLY
ACROSS SOUTHERN NEVADA...NORTHWEST ARIZONA AND THE HIGHER ELEVATIONS
OF INYO COUNTY. THE PRIMARY THREAT WITH STORMS TODAY WILL ONCE AGAIN
BE LOCALLY HEAVY RAIN THAT COULD RESULT IN FLASH FLOODING. ALTHOUGH
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THROUGH THE
END OF THE WEEK...THE BEST CHANCES SHOULD BE NORTH AND EAST OF LAS
VEGAS. HIGH TEMPERATURES SHOULD GRADUALLY RETURN TO NEAR NORMAL
LEVELS BY THE MIDDLE OF THE WEEK.
&&

.UPDATE...IT JUST KEEPS ON GOING. CONVECTION ACROSS MOHAVE COUNTY IS
STILL GOING. EVEN THOUGH CLOUD TOPS HAVE WARMED QUITE A BIT IN THE
LAST HOUR, THE AREAL EXTENT OF ACTIVITY HAS SPREAD OUT MORE THAN
EXPECTED AND WILL LIKELY LAST PAST 12Z. THEREFORE, I WENT AHEAD AND
ADJUSTED POPS TO MATCH THE LATEST RADAR TRENDS, ESPECIALLY ACROSS
EASTERN SAN BERNARDINO COUNTY WHERE LIGHT RAIN WAS COVERING A LARGE
AREA. THE REST OF THE FORECAST STILL LOOKS GOOD.
&&

.PREVIOUS DISCUSSION...
ISSUED AT 304 AM PDT SUN SEP 1 2013

.SHORT TERM...CONVECTION HAS REFUSED TO GO AWAY TONIGHT ACROSS
MOHAVE, SOUTHERN CLARK AND NORTHEAST SAN BERNARDINO COUNTIES AS
ACTIVITY THAT DEVELOPED EARLIER BEHIND AN OUTFLOW BOUNDARY THAT
PUSHED SOUTH ACROSS THE AREA BLOSSOMED AND HAS MANAGED TO DUMP SOME
HEFTY AMOUNTS OF RAIN. ONE AUTOMATED RAIN GAUGE NEAR SEARCHLIGHT HAS
MEASURED 2.60 INCHES OF RAIN IN ABOUT 2 HOURS AND VERY HEAVY RAIN
WAS FALLING AROUND YUCCA AND OTHER AREAS IN SOUTH-CENTRAL MOHAVE
COUNTY. CLOUD TOPS HAVE ACTUALLY COOLED IN THE LAST HOUR OR SO WITH
THIS CONVECTIVE COMPLEX WITH VALUES PUSHING -72C WHICH IS IMPRESSIVE
FOR ANYTIME OF DAY BUT ESPECIALLY AT THIS HOUR OF THE NIGHT. THIS
CONVECTIVE COMPLEX OVER MOHAVE COUNTY WILL BE THE MAIN ISSUE WITH
THE INITIAL PORTIONS OF THE FORECAST AS IT MAY WORK OVER ENOUGH OF
THE SOUTHEAST PORTIONS OF THE AREA TO INHIBIT CONVECTION UNTIL LATER
TODAY OR EVEN POSSIBLY ALTOGETHER. ELSEWHERE THINGS HAVE RELATIVELY
CALMED DOWN AND CLOUD COVER HAS CLEARED OUT ESPECIALLY ACROSS MUCH
OF THE NORTHWEST CWFA.

FOR TODAY, THE FLOW ALOFT WILL START TO TAKE ON MORE OF A SOUTHWEST
COMPONENT ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE CWFA. WHILE
THIS WILL TRY TO BRING IN SOME DRIER AIR, THERE IS SO MUCH MOISTURE
IN PLACE, ALONG WITH SUFFICIENT INSTABILITY, THAT IT IS HARD TO
DISCOUNT THUNDERSTORMS DEVELOPING ANYWHERE FROM LATE THIS MORNING
INTO THIS AFTERNOON AND EVENING. HOWEVER, LOOKING AT 700-300 MB
THETA E VALUES THERE IS A NOTICEABLE INCREASE IN VALUES ABOVE 340K
ACROSS LINCOLN, CLARK AND NORTHERN MOHAVE COUNTIES WHICH ALSO
MATCHES WHERE THE BEST COMPUTED CAPE VALUES ARE SHOWN. SO, WE HAVE
CONTINUED WITH THE HIGHEST POPS ACROSS THESE AREAS. IN ADDITION, A
WEAK RIPPLE IN THE MID-LEVELS (A WEAK INVERTED TROUGH) AND A
POTENTIAL ASSOCIATED PIECE OF ENERGY ARE SHOWN TO LIFT NORTHEAST
ACROSS SOUTHERN NEVADA LATE THIS AFTERNOON INTO THIS EVENING WHICH
MAY FURTHER HELP TO ENHANCE CONVECTION IN THESE AREAS AND COULD EVEN
KEEP IT GOING LATER THIS EVENING AND INTO LATE TONIGHT THAN WHAT WE
SEE GO ON ELSEWHERE. WITH THAT, I WENT AHEAD AND ADJUSTED UP POPS
FOR LINCOLN AND NORTHERN MOHAVE COUNTIES INTO THE LATER PORTIONS OF
TONIGHT. THE FLASH FLOOD WATCH WAS EXTENDED FOR THESE AREAS LAST
EVENING FOR THE ONGOING CONVECTION, SO EVEN THOUGH MODELS SHOW
THINGS NOT GETTING GOING UNTIL BETWEEN 10 AM AND NOON, IT WILL
REMAIN OUT. THE STEERING FLOW TODAY WILL BE STRONGER AND MORE WELL
DEFINED FROM THE SOUTHWEST THAN THE ZIG-ZAG NATURE WE HAD YESTERDAY,
AND THUS WE WILL NEED TO WATCH IN THE LAS VEGAS VALLEY FOR ACTIVITY
TO MOVE IN FROM THE SPRING MOUNTAINS BY LATE THIS MORNING AND INTO
THIS AFTERNOON. THIS COULD PRESENT PROBLEMS WITH THE CARPENTER 1
FIRE BURN AREA AND WE WILL NEED TO WATCH OUT AGAIN FOR DEBRIS FLOWS.

ELSEWHERE, BOTH THE GFS AND ECMWF AS WELL AS THE HRRR MODEL SUGGEST
THAT ACTIVITY SHOULD GET GOING ACROSS THE SOUTHERN SIERRA, WHITE
MOUNTAINS AS WELL AS MOUNTAINS OF ESMERALDA AND CENTRAL NYE
COUNTIES. ENOUGH INSTABILITY AND CAPE ARE SHOWN THERE AS IS MOISTURE
TO JUSTIFY ADDING THESE AREAS TO THE FLASH FLOOD WATCH, HOWEVER
SINCE ACTIVITY WILL LIKELY TAKE UNTIL LATER THIS MORNING, THE WATCH
WILL START HERE AT 11 AM. AGAIN, THE STEERING FLOW WILL BE FROM THE
SOUTHWEST WHICH COULD DRIVE STORMS THAT DEVELOP ALONG THE SOUTHERN
SIERRA CREST INTO THE OWENS VALLEY LATER THIS AFTERNOON AND THIS
EVENING. WE MAY GET A LITTLE MORE ISSUES WITH WIND HERE AS THERE
WILL BE A LITTLE MORE LOWER LEVEL DRYING THAT TAKES PLACE AND STORMS
MAY GET SOME MOMENTUM AS THEY DROP OFF THE MOUNTAINS AND INTO THE
VALLEYS AND THE AIR ACCELERATES DOWN THE TERRAIN.

TEMPS TODAY SHOULD BE A FEW DEGREES WARMER THAN SATURDAY, EXCEPT
WHERE CLOUDS ARE THICKER AND CONVECTION DEVELOPS EARLIER.

FOR LABOR DAY, THE TROUGH APPROACHING NORCAL WILL KEEP THE FLOW
ALOFT SOUTHWEST TO SOUTH. EVEN THOUGH A LITTLE DRYING TAKES PLACE
ACROSS SOUTHEAST CALIFORNIA, THERE IS STILL ENOUGH MOISTURE AND
INSTABILITY TO KEEP THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
AROUND EVERYWHERE. HOWEVER, THE BEST MOISTURE REMAINS NORTH AND EAST
OF LAS VEGAS, WHICH IS WHERE THE HIGHEST POPS WERE PLACED. HOWEVER,
IT DOES APPEAR THAT THE COVERAGE OF STORMS WILL BE AS GREAT AS WHAT
WE COULD SEE TODAY. WITH A LESS IN THE WAY OF STORMS, THERE COULD BE
MORE SUN AND THUS TEMPS SHOULD BE A LITTLE WARMER.

ONE THING TO WATCH TODAY AND MONDAY WILL BE HOW MUCH ACTIVITY GETS
GOING ON THE MOIST-DRY INTERFACE AS THIS AREA MAY BE MORE ACTIVE
THAN WHAT THE MODELS SHOW. TODAY MAY HELP PROVIDE SOME CLUES AS TO
WHAT WE COULD SEE ALONG THAT INTERFACE TOMORROW.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...HIGH PRESSURE WILL
PERSIST ROUGHLY NEAR THE FOUR CORNERS AREA MONDAY NIGHT THROUGH
FRIDAY WITH GENERALLY A SOUTHERLY FLOW OVER THE FORECAST AREA. THIS
WILL KEEP MONSOON MOISTURE IN PLACE WITH ISOLATED TO SCATTERED
THUNDERSTORMS EACH DAY. THE GFS AND ECMWF ARE IN FAIR AGREEMENT FOR
A BIT OF A PATTERN CHANGE BY SATURDAY WITH A LOW PRESSURE SYSTEM
FINALLY MOVING EAST THROUGH THE PACIFIC NORTHWEST. THE RESULT IS A
WEST TO MAYBE EVEN NORTHWEST FLOW OVER THE NORTHERN PART OF THE
FORECAST AREA BRINGING IN DRIER AIR. THIS MAY BRING AN END TO THE
THUNDERSTORM CHANCES FOR THE FAR NORTH AND PARTS OF THE WESTERN CWA.
GUIDANCE CONTINUES TO INDICATE TEMPERATURES A TOUCH ABOVE NORMAL FOR
MOST OF THE LONG TERM.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL FAVOR TYPICAL DIURNAL TRENDS
AWAY FROM ANY SHRA/TSRA THROUGH TONIGHT. SCT-BKN CLOUDS AOA 10-15K
FEET ARE EXPECTED THROUGH TONIGHT. SHRA/TSRA ARE EXPECTED TO DEVELOP
IN AND AROUND THE LAS VEGAS VALLEY AND IN THE APPROACH CORRIDORS ON
TODAY AFTER 18Z AND DIMINISH BETWEEN 04Z AND 07Z MONDAY. GUSTY AND
ERRATIC WINDS...REDUCED CIGS AND VSBY ARE POSSIBLE IN AND NEAR ANY
SHRA/TSRA AND OUTFLOW BOUNDARIES WHICH MAY IMPACT CONFIGURATIONS.
THE FLOW IN THE ATMOSPHERE IS FROM THE SOUTHWEST TO WEST THROUGH
TONIGHT WHICH WOULD FAVOR PUSHING SHRA/TSRA IN FROM THE SPRING
MOUNTAINS TOWARD THE AIRPORT COMPLEX.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...EXPECT SCT-BKN CLOUDS AOA 10-15K FEET WITH WINDS
FAVORING TYPICAL DIURNAL TRENDS THROUGH TONIGHT AWAY FROM ANY
SHRA/TSRA. REDUCED CIGS AND VSBY AND GUSTY AND ERRATIC WINDS IN AND
NEAR SHRA/TSRA WILL BE THE MAIN THREATS. SHRA AND TSRA ARE EXPECTED
AFTER 18Z SUNDAY BEFORE DECREASING AROUND 06Z MONDAY WITH ACTIVITY
MOST LIKELY IN LINCOLN, CLARK, ESMERALDA, MOHAVE, CENTRAL NYE AND
WESTERN INYO COUNTIES. SHRA/TSRA SHOULD MAINLY FROM EAST THROUGH
TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NVZ015-016-018>022.
     FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR NVZ014.
AZ...FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ001>003-036.
CA...FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR CAZ519>521.
&&

$$

STACHELSKI/HARRISON

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER







AREA FORECAST DISCUSSION

NWS LAS VEGAS NV

 304 AM PDT SUN SEP 1 2013

.SYNOPSIS...MOIST AND UNSTABLE AIR WILL ONCE AGAIN RESULT ON SHOWERS
AND THUNDERSTORMS ACROSS THE AREA THROUGH THIS EVENING ESPECIALLY
ACROSS SOUTHERN NEVADA...NORTHWEST ARIZONA AND THE HIGHER ELEVATIONS
OF INYO COUNTY. THE PRIMARY THREAT WITH STORMS TODAY WILL ONCE AGAIN
BE LOCALLY HEAVY RAIN THAT COULD RESULT IN FLASH FLOODING. ALTHOUGH
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THROUGH THE
END OF THE WEEK...THE BEST CHANCES SHOULD BE NORTH AND EAST OF LAS
VEGAS. HIGH TEMPERATURES SHOULD GRADUALLY RETURN TO NEAR NORMAL
LEVELS BY THE MIDDLE OF THE WEEK.
&&

.SHORT TERM...CONVECTION HAS REFUSED TO GO AWAY TONIGHT ACROSS
MOHAVE, SOUTHERN CLARK AND NORTHEAST SAN BERNARDINO COUNTIES AS
ACTIVITY THAT DEVELOPED EARLIER BEHIND AN OUTFLOW BOUNDARY THAT
PUSHED SOUTH ACROSS THE AREA BLOSSOMED AND HAS MANAGED TO DUMP SOME
HEFTY AMOUNTS OF RAIN. ONE AUTOMATED RAIN GAUGE NEAR SEARCHLIGHT HAS
MEASURED 2.60 INCHES OF RAIN IN ABOUT 2 HOURS AND VERY HEAVY RAIN
WAS FALLING AROUND YUCCA AND OTHER AREAS IN SOUTH-CENTRAL MOHAVE
COUNTY. CLOUD TOPS HAVE ACTUALLY COOLED IN THE LAST HOUR OR SO WITH
THIS CONVECTIVE COMPLEX WITH VALUES PUSHING -72C WHICH IS IMPRESSIVE
FOR ANYTIME OF DAY BUT ESPECIALLY AT THIS HOUR OF THE NIGHT. THIS
CONVECTIVE COMPLEX OVER MOHAVE COUNTY WILL BE THE MAIN ISSUE WITH
THE INITIAL PORTIONS OF THE FORECAST AS IT MAY WORK OVER ENOUGH OF
THE SOUTHEAST PORTIONS OF THE AREA TO INHIBIT CONVECTION UNTIL LATER
TODAY OR EVEN POSSIBLY ALTOGETHER. ELSEWHERE THINGS HAVE RELATIVELY
CALMED DOWN AND CLOUD COVER HAS CLEARED OUT ESPECIALLY ACROSS MUCH
OF THE NORTHWEST CWFA.

FOR TODAY, THE FLOW ALOFT WILL START TO TAKE ON MORE OF A SOUTHWEST
COMPONENT ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE CWFA. WHILE
THIS WILL TRY TO BRING IN SOME DRIER AIR, THERE IS SO MUCH MOISTURE
IN PLACE, ALONG WITH SUFFICIENT INSTABILITY, THAT IT IS HARD TO
DISCOUNT THUNDERSTORMS DEVELOPING ANYWHERE FROM LATE THIS MORNING
INTO THIS AFTERNOON AND EVENING. HOWEVER, LOOKING AT 700-300 MB
THETA E VALUES THERE IS A NOTICEABLE INCREASE IN VALUES ABOVE 340K
ACROSS LINCOLN, CLARK AND NORTHERN MOHAVE COUNTIES WHICH ALSO
MATCHES WHERE THE BEST COMPUTED CAPE VALUES ARE SHOWN. SO, WE HAVE
CONTINUED WITH THE HIGHEST POPS ACROSS THESE AREAS. IN ADDITION, A
WEAK RIPPLE IN THE MID-LEVELS (A WEAK INVERTED TROUGH) AND A
POTENTIAL ASSOCIATED PIECE OF ENERGY ARE SHOWN TO LIFT NORTHEAST
ACROSS SOUTHERN NEVADA LATE THIS AFTERNOON INTO THIS EVENING WHICH
MAY FURTHER HELP TO ENHANCE CONVECTION IN THESE AREAS AND COULD EVEN
KEEP IT GOING LATER THIS EVENING AND INTO LATE TONIGHT THAN WHAT WE
SEE GO ON ELSEWHERE. WITH THAT, I WENT AHEAD AND ADJUSTED UP POPS
FOR LINCOLN AND NORTHERN MOHAVE COUNTIES INTO THE LATER PORTIONS OF
TONIGHT. THE FLASH FLOOD WATCH WAS EXTENDED FOR THESE AREAS LAST
EVENING FOR THE ONGOING CONVECTION, SO EVEN THOUGH MODELS SHOW
THINGS NOT GETTING GOING UNTIL BETWEEN 10 AM AND NOON, IT WILL REMAIN
OUT. THE STEERING FLOW TODAY WILL BE STRONGER AND MORE WELL DEFINED
FROM THE SOUTHWEST THAN THE ZIG-ZAG NATURE WE HAD YESTERDAY, AND
THUS WE WILL NEED TO WATCH IN THE LAS VEGAS VALLEY FOR ACTIVITY TO
MOVE IN FROM THE SPRING MOUNTAINS BY LATE THIS MORNING AND INTO THIS
AFTERNOON. THIS COULD PRESENT PROBLEMS WITH THE CARPENTER 1 FIRE
BURN AREA AND WE WILL NEED TO WATCH OUT AGAIN FOR DEBRIS FLOWS.

ELSEWHERE, BOTH THE GFS AND ECMWF AS WELL AS THE HRRR MODEL SUGGEST
THAT ACTIVITY SHOULD GET GOING ACROSS THE SOUTHERN SIERRA, WHITE
MOUNTAINS AS WELL AS MOUNTAINS OF ESMERALDA AND CENTRAL NYE
COUNTIES. ENOUGH INSTABILITY AND CAPE ARE SHOWN THERE AS IS MOISTURE
TO JUSTIFY ADDING THESE AREAS TO THE FLASH FLOOD WATCH, HOWEVER
SINCE ACTIVITY WILL LIKELY TAKE UNTIL LATER THIS MORNING, THE WATCH
WILL START HERE AT 11 AM. AGAIN, THE STEERING FLOW WILL BE FROM THE
SOUTHWEST WHICH COULD DRIVE STORMS THAT DEVELOP ALONG THE SOUTHERN
SIERRA CREST INTO THE OWENS VALLEY LATER THIS AFTERNOON AND THIS
EVENING. WE MAY GET A LITTLE MORE ISSUES WITH WIND HERE AS THERE
WILL BE A LITTLE MORE LOWER LEVEL DRYING THAT TAKES PLACE AND STORMS
MAY GET SOME MOMENTUM AS THEY DROP OFF THE MOUNTAINS AND INTO THE
VALLEYS AND THE AIR ACCELERATES DOWN THE TERRAIN.

TEMPS TODAY SHOULD BE A FEW DEGREES WARMER THAN SATURDAY, EXCEPT
WHERE CLOUDS ARE THICKER AND CONVECTION DEVELOPS EARLIER.

FOR LABOR DAY, THE TROUGH APPROACHING NORCAL WILL KEEP THE FLOW
ALOFT SOUTHWEST TO SOUTH. EVEN THOUGH A LITTLE DRYING TAKES PLACE
ACROSS SOUTHEAST CALIFORNIA, THERE IS STILL ENOUGH MOISTURE AND
INSTABILITY TO KEEP THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
AROUND EVERYWHERE. HOWEVER, THE BEST MOISTURE REMAINS NORTH AND EAST
OF LAS VEGAS, WHICH IS WHERE THE HIGHEST POPS WERE PLACED. HOWEVER,
IT DOES APPEAR THAT THE COVERAGE OF STORMS WILL BE AS GREAT AS WHAT
WE COULD SEE TODAY. WITH A LESS IN THE WAY OF STORMS, THERE COULD BE
MORE SUN AND THUS TEMPS SHOULD BE A LITTLE WARMER.

ONE THING TO WATCH TODAY AND MONDAY WILL BE HOW MUCH ACTIVITY GETS
GOING ON THE MOIST-DRY INTERFACE AS THIS AREA MAY BE MORE ACTIVE
THAN WHAT THE MODELS SHOW. TODAY MAY HELP PROVIDE SOME CLUES AS TO
WHAT WE COULD SEE ALONG THAT INTERFACE TOMORROW.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...HIGH PRESSURE WILL
PERSIST ROUGHLY NEAR THE FOUR CORNERS AREA MONDAY NIGHT THROUGH
FRIDAY WITH GENERALLY A SOUTHERLY FLOW OVER THE FORECAST AREA. THIS
WILL KEEP MONSOON MOISTURE IN PLACE WITH ISOLATED TO SCATTERED
THUNDERSTORMS EACH DAY. THE GFS AND ECMWF ARE IN FAIR AGREEMENT FOR
A BIT OF A PATTERN CHANGE BY SATURDAY WITH A LOW PRESSURE SYSTEM
FINALLY MOVING EAST THROUGH THE PACIFIC NORTHWEST. THE RESULT IS A
WEST TO MAYBE EVEN NORTHWEST FLOW OVER THE NORTHERN PART OF THE
FORECAST AREA BRINGING IN DRIER AIR. THIS MAY BRING AN END TO THE
THUNDERSTORM CHANCES FOR THE FAR NORTH AND PARTS OF THE WESTERN CWA.
GUIDANCE CONTINUES TO INDICATE TEMPERATURES A TOUCH ABOVE NORMAL FOR
MOST OF THE LONG TERM.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL FAVOR TYPICAL DIURNAL TRENDS
AWAY FROM ANY SHRA/TSRA THROUGH TONIGHT. SCT-BKN CLOUDS AOA 10-15K
FEET ARE EXPECTED THROUGH TONIGHT. SHRA/TSRA ARE EXPECTED TO DEVELOP
IN AND AROUND THE LAS VEGAS VALLEY AND IN THE APPROACH CORRIDORS ON
TODAY AFTER 18Z AND DIMINISH BETWEEN 04Z AND 07Z MONDAY. GUSTY AND
ERRATIC WINDS...REDUCED CIGS AND VSBY ARE POSSIBLE IN AND NEAR ANY
SHRA/TSRA AND OUTFLOW BOUNDARIES WHICH MAY IMPACT CONFIGURATIONS.
THE FLOW IN THE ATMOSPHERE IS FROM THE SOUTHWEST TO WEST THROUGH
TONIGHT WHICH WOULD FAVOR PUSHING SHRA/TSRA IN FROM THE SPRING
MOUNTAINS TOWARD THE AIRPORT COMPLEX.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...EXPECT SCT-BKN CLOUDS AOA 10-15K FEET WITH WINDS
FAVORING TYPICAL DIURNAL TRENDS THROUGH TONIGHT AWAY FROM ANY
SHRA/TSRA. REDUCED CIGS AND VSBY AND GUSTY AND ERRATIC WINDS IN AND
NEAR SHRA/TSRA WILL BE THE MAIN THREATS. SHRA AND TSRA ARE EXPECTED
AFTER 18Z SUNDAY BEFORE DECREASING AROUND 06Z MONDAY WITH ACTIVITY
MOST LIKELY IN LINCOLN, CLARK, ESMERALDA, MOHAVE, CENTRAL NYE AND
WESTERN INYO COUNTIES. SHRA/TSRA SHOULD MAINLY FROM EAST THROUGH
TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NVZ015-016-018>022.
     FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR NVZ014.
AZ...FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ001>003-036.
CA...FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR CAZ519>521.
&&

$$

STACHELSKI/HARRISON

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER










AREA FORECAST DISCUSSION

NWS LAS VEGAS NV

 303 AM PDT SUN SEP 1 2013

.SYNOPSIS...MOIST AND UNSTABLE AIR WILL ONCE AGAIN RESULT ON SHOWERS
AND THUNDERSTORMS ACROSS THE AREA THROUGH THIS EVENING ESPECIALLY
ACROSS SOUTHERN NEVADA...NORTHWEST ARIZONA AND THE HIGHER ELEVATIONS
OF INYO COUNTY. THE PRIMARY THREAT WITH STORMS TODAY WILL ONCE AGAIN
BE LOCALLY HEAVY RAIN THAT COULD RESULT IN FLASH FLOODING. ALTHOUGH
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THROUGH THE
END OF THE WEEK...THE BEST CHANCES SHOULD BE NORTH AND EAST OF LAS
VEGAS. HIGH TEMPERATURES SHOULD GRADUALLY RETURN TO NEAR NORMAL
LEVELS BY THE MIDDLE OF THE WEEK.
&&

.SHORT TERM...CONVECTION HAS REFUSED TO GO AWAY TONIGHT ACROSS
MOHAVE, SOUTHERN CLARK AND NORTHEAST SAN BERNARDINO COUNTIES AS
ACTIVITY THAT DEVELOPED EARLIER BEHIND AN OUTFLOW BOUNDARY THAT
PUSHED SOUTH ACROSS THE AREA BLOSSOMED AND HAS MANAGED TO DUMP SOME
HEFTY AMOUNTS OF RAIN. ONE AUTOMATED RAIN GAUGE NEAR SEARCHLIGHT HAS
MEASURED 2.60 INCHES OF RAIN IN ABOUT 2 HOURS AND VERY HEAVY RAIN
WAS FALLING AROUND YUCCA AND OTHER AREAS IN SOUTH-CENTRAL MOHAVE
COUNTY. CLOUD TOPS HAVE ACTUALLY COOLED IN THE LAST HOUR OR SO WITH
THIS CONVECTIVE COMPLEX WITH VALUES PUSHING -72C WHICH IS IMPRESSIVE
FOR ANYTIME OF DAY BUT ESPECIALLY AT THIS HOUR OF THE NIGHT. THIS
CONVECTIVE COMPLEX OVER MOHAVE COUNTY WILL BE THE MAIN ISSUE WITH
THE INITIAL PORTIONS OF THE FORECAST AS IT MAY WORK OVER ENOUGH OF
THE SOUTHEAST PORTIONS OF THE AREA TO INHIBIT CONVECTION UNTIL LATER
TODAY OR EVEN POSSIBLY ALTOGETHER. ELSEWHERE THINGS HAVE RELATIVELY
CALMED DOWN AND CLOUD COVER HAS CLEARED OUT ESPECIALLY ACROSS MUCH
OF THE NORTHWEST CWFA.

FOR TODAY, THE FLOW ALOFT WILL START TO TAKE ON MORE OF A SOUTHWEST
COMPONENT ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE CWFA. WHILE
THIS WILL TRY TO BRING IN SOME DRIER AIR, THERE IS SO MUCH MOISTURE
IN PLACE, ALONG WITH SUFFICIENT INSTABILITY, THAT IT IS HARD TO
DISCOUNT THUNDERSTORMS DEVELOPING ANYWHERE FROM LATE THIS MORNING
INTO THIS AFTERNOON AND EVENING. HOWEVER, LOOKING AT 700-300 MB
THETA E VALUES THERE IS A NOTICEABLE INCREASE IN VALUES ABOVE 340K
ACROSS LINCOLN, CLARK AND NORTHERN MOHAVE COUNTIES WHICH ALSO
MATCHES WHERE THE BEST COMPUTED CAPE VALUES ARE SHOWN. SO, WE HAVE
CONTINUED WITH THE HIGHEST POPS ACROSS THESE AREAS. IN ADDITION, A
WEAK RIPPLE IN THE MID-LEVELS (A WEAK INVERTED TROUGH) AND A
POTENTIAL ASSOCIATED PIECE OF ENERGY ARE SHOWN TO LIFT NORTHEAST
ACROSS SOUTHERN NEVADA LATE THIS AFTERNOON INTO THIS EVENING WHICH
MAY FURTHER HELP TO ENHANCE CONVECTION IN THESE AREAS AND COULD EVEN
KEEP IT GOING LATER THIS EVENING AND INTO LATE TONIGHT THAN WHAT WE
SEE GO ON ELSEWHERE. WITH THAT, I WENT AHEAD AND ADJUSTED UP POPS
FOR LINCOLN AND NORTHERN MOHAVE COUNTIES INTO THE LATER PORTIONS OF
TONIGHT. THE FLASH FLOOD WATCH WAS EXTENDED FOR THESE AREAS LAST
EVENING FOR THE ONGOING CONVECTION, SO EVEN THOUGH MODELS SHOW
THINGS NOT GET GOING UNTIL BETWEEN 10 AM AND NOON, IT WILL REMAIN
OUT. THE STEERING FLOW TODAY WILL BE STRONGER AND MORE WELL DEFINED
FROM THE SOUTHWEST THAN THE ZIG-ZAG NATURE WE HAD YESTERDAY, AND
THUS WE WILL NEED TO WATCH IN THE LAS VEGAS VALLEY FOR ACTIVITY TO
MOVE IN FROM THE SPRING MOUNTAINS BY LATE THIS MORNING AND INTO THIS
AFTERNOON. THIS COULD PRESENT PROBLEMS WITH THE CARPENTER 1 FIRE
BURN AREA AND WE WILL NEED TO WATCH OUT AGAIN FOR DEBRIS FLOWS.

ELSEWHERE, BOTH THE GFS AND ECMWF AS WELL AS THE HRRR MODEL SUGGEST
THAT ACTIVITY SHOULD GET GOING ACROSS THE SOUTHERN SIERRA, WHITE
MOUNTAINS AS WELL AS MOUNTAINS OF ESMERALDA AND CENTRAL NYE
COUNTIES. ENOUGH INSTABILITY AND CAPE ARE SHOWN THERE AS IS MOISTURE
TO JUSTIFY ADDING THESE AREAS TO THE FLASH FLOOD WATCH, HOWEVER
SINCE ACTIVITY WILL LIKELY TAKE UNTIL LATER THIS MORNING, THE WATCH
WILL START HERE AT 11 AM. AGAIN, THE STEERING FLOW WILL BE FROM THE
SOUTHWEST WHICH COULD DRIVE STORMS THAT DEVELOP ALONG THE SOUTHERN
SIERRA CREST INTO THE OWENS VALLEY LATER THIS AFTERNOON AND THIS
EVENING. WE MAY GET A LITTLE MORE ISSUES WITH WIND HERE AS THERE
WILL BE A LITTLE MORE LOWER LEVEL DRYING THAT TAKES PLACE AND STORMS
MAY GET SOME MOMENTUM AS THEY DROP OFF THE MOUNTAINS AND INTO THE
VALLEYS AND THE AIR ACCELERATES DOWN THE TERRAIN.

TEMPS TODAY SHOULD BE A FEW DEGREES WARMER THAN SATURDAY, EXCEPT
WHERE CLOUDS ARE THICKER AND CONVECTION DEVELOPS EARLIER.

FOR LABOR DAY, THE TROUGH APPROACHING NORCAL WILL KEEP THE FLOW
ALOFT SOUTHWEST TO SOUTH. EVEN THOUGH A LITTLE DRYING TAKES PLACE
ACROSS SOUTHEAST CALIFORNIA, THERE IS STILL ENOUGH MOISTURE AND
INSTABILITY TO KEEP THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
AROUND EVERYWHERE. HOWEVER, THE BEST MOISTURE REMAINS NORTH AND EAST
OF LAS VEGAS, WHICH IS WHERE THE HIGHEST POPS WERE PLACED. HOWEVER,
IT DOES APPEAR THAT THE COVERAGE OF STORMS WILL BE AS GREAT AS WHAT
WE COULD SEE TODAY. WITH A LESS IN THE WAY OF STORMS, THERE COULD BE
MORE SUN AND THUS TEMPS SHOULD BE A LITTLE WARMER.

ONE THING TO WATCH TODAY AND MONDAY WILL BE HOW MUCH ACTIVITY GETS
GOING ON THE MOIST-DRY INTERFACE AS THIS AREA MAY BE MORE ACTIVE
THAN WHAT THE MODELS SHOW. TODAY MAY HELP PROVIDE SOME CLUES AS TO
WHAT WE COULD SEE ALONG THAT INTERFACE TOMORROW.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...HIGH PRESSURE WILL
PERSIST ROUGHLY NEAR THE FOUR CORNERS AREA MONDAY NIGHT THROUGH
FRIDAY WITH GENERALLY A SOUTHERLY FLOW OVER THE FORECAST AREA. THIS
WILL KEEP MONSOON MOISTURE IN PLACE WITH ISOLATED TO SCATTERED
THUNDERSTORMS EACH DAY. THE GFS AND ECMWF ARE IN FAIR AGREEMENT FOR
A BIT OF A PATTERN CHANGE BY SATURDAY WITH A LOW PRESSURE SYSTEM
FINALLY MOVING EAST THROUGH THE PACIFIC NORTHWEST. THE RESULT IS A
WEST TO MAYBE EVEN NORTHWEST FLOW OVER THE NORTHERN PART OF THE
FORECAST AREA BRINGING IN DRIER AIR. THIS MAY BRING AN END TO THE
THUNDERSTORM CHANCES FOR THE FAR NORTH AND PARTS OF THE WESTERN CWA.
GUIDANCE CONTINUES TO INDICATE TEMPERATURES A TOUCH ABOVE NORMAL FOR
MOST OF THE LONG TERM.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL FAVOR TYPICAL DIURNAL TRENDS
AWAY FROM ANY SHRA/TSRA THROUGH TONIGHT. SCT-BKN CLOUDS AOA 10-15K
FEET ARE EXPECTED THROUGH TONIGHT. SHRA/TSRA ARE EXPECTED TO DEVELOP
IN AND AROUND THE LAS VEGAS VALLEY AND IN THE APPROACH CORRIDORS ON
TODAY AFTER 18Z AND DIMINISH BETWEEN 04Z AND 07Z MONDAY. GUSTY AND
ERRATIC WINDS...REDUCED CIGS AND VSBY ARE POSSIBLE IN AND NEAR ANY
SHRA/TSRA AND OUTFLOW BOUNDARIES WHICH MAY IMPACT CONFIGURATIONS.
THE FLOW IN THE ATMOSPHERE IS FROM THE SOUTHWEST TO WEST THROUGH
TONIGHT WHICH WOULD FAVOR PUSHING SHRA/TSRA IN FROM THE SPRING
MOUNTAINS TOWARD THE AIRPORT COMPLEX.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...EXPECT SCT-BKN CLOUDS AOA 10-15K FEET WITH WINDS
FAVORING TYPICAL DIURNAL TRENDS THROUGH TONIGHT AWAY FROM ANY
SHRA/TSRA. REDUCED CIGS AND VSBY AND GUSTY AND ERRATIC WINDS IN AND
NEAR SHRA/TSRA WILL BE THE MAIN THREATS. SHRA AND TSRA ARE EXPECTED
AFTER 18Z SUNDAY BEFORE DECREASING AROUND 06Z MONDAY WITH ACTIVITY
MOST LIKELY IN LINCOLN, CLARK, ESMERALDA, MOHAVE, CENTRAL NYE AND
WESTERN INYO COUNTIES. SHRA/TSRA SHOULD MAINLY FROM EAST THROUGH
TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NVZ015-016-018>022.
     FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR NVZ014.
AZ...FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ001>003-036.
CA...FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR CAZ519>521.
&&

$$

STACHELSKI/HARRISON

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER









AREA FORECAST DISCUSSION

NWS LAS VEGAS NV

 301 AM PDT SUN SEP 1 2013

.SYNOPSIS...MOIST AND UNSTABLE AIR WILL ONCE AGAIN RESULT ON SHOWERS
AND THUNDERSTORMS ACROSS THE AREA THROUGH THIS EVENING ESPECIALLY
ACROSS SOUTHERN NEVADA...NORTHWEST ARIZONA AND THE HIGHER ELEVATIONS
OF INYO COUNTY. THE PRIMARY THREAT WITH STORMS TODAY WILL ONCE AGAIN
BE LOCALLY HEAVY RAIN THAT COULD RESULT IN FLASH FLOODING. ALTHOUGH
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THROUGH THE
END OF THE WEEK...THE BEST CHANCES SHOULD BE NORTH AND EAST OF LAS
VEGAS. HIGH TEMPERATURES SHOULD GRADUALLY RETURN TO NEAR NORMAL
LEVELS BY THE MIDDLE OF THE WEEK.
&&

.SHORT TERM...CONVECTION HAS REFUSED TO GO AWAY TONIGHT ACROSS
MOHAVE, SOUTHERN CLARK AND NORTHEAST SAN BERNARDINO COUNTIES AS
ACTIVITY THAT DEVELOPED EARLIER BEHIND AN OUTFLOW BOUNDARY THAT
PUSHED SOUTH ACROSS THE AREA BLOSSOMED AND HAS MANAGED TO DUMP SO
HEFTY AMOUNTS OF RAIN. ONE AUTOMATED RAIN GAUGE NEAR SEARCHLIGHT HAS
MEASURED 2.60 INCHES OF RAIN IN ABOUT 2 HOURS AND VERY HEAVY RAIN
WAS FALLING AROUND YUCCA AND OTHER AREAS IN SOUTH-CENTRAL MOHAVE
COUNTY. CLOUD TOPS HAVE ACTUALLY COOLED IN THE LAST HOUR OR SO WITH
THIS CONVECTIVE COMPLEX WITH VALUES PUSHING -72C WHICH IS IMPRESSIVE
FOR ANYTIME OF DAY BUT ESPECIALLY AT THIS HOUR OF THE NIGHT. THIS
CONVECTIVE COMPLEX OVER MOHAVE COUNTY WILL BE THE MAIN ISSUE WITH
THE INITIAL PORTIONS OF THE FORECAST AS IT MAY WORK OVER ENOUGH OF
THE SOUTHEAST PORTIONS OF THE AREA TO INHIBIT CONVECTION UNTIL LATER
TODAY OR EVEN POSSIBLY ALTOGETHER. ELSEWHERE THINGS HAVE RELATIVELY
CALMED DOWN AND CLOUD COVER HAS CLEARED OUT ESPECIALLY ACROSS MUCH
OF THE NORTHWEST CWFA.

FOR TODAY, THE FLOW ALOFT WILL START TO TAKE ON MORE OF A SOUTHWEST
COMPONENT ESPECIALLY ACROSS THE WESTERN PORTIONS OF THE CWFA. WHILE
THIS WILL TRY TO BRING IN SOME DRIER AIR, THERE IS SO MUCH MOISTURE
IN PLACE, ALONG WITH SUFFICIENT INSTABILITY, THAT IT IS HARD TO
DISCOUNT THUNDERSTORMS DEVELOPING ANYWHERE FROM LATE THIS MORNING
INTO THIS AFTERNOON AND EVENING. HOWEVER, LOOKING AT 700-300 MB
THETA E VALUES THERE IS A NOTICEABLE INCREASE IN VALUES ABOVE 340K
ACROSS LINCOLN, CLARK AND NORTHERN MOHAVE COUNTIES WHICH ALSO
MATCHES WHERE THE BEST COMPUTED CAPE VALUES ARE SHOWN. SO, WE HAVE
CONTINUED WITH THE HIGHEST POPS ACROSS THESE AREAS. IN ADDITION, A
WEAK RIPPLE IN THE MID-LEVELS (A WEAK INVERTED TROUGH) AND A
POTENTIAL ASSOCIATED PIECE OF ENERGY ARE SHOWN TO LIFT NORTHEAST
ACROSS SOUTHERN NEVADA LATE THIS AFTERNOON INTO THIS EVENING WHICH
MAY FURTHER HELP TO ENHANCE CONVECTION IN THESE AREAS AND COULD EVEN
KEEP IT GOING LATER THIS EVENING AND INTO LATE TONIGHT THAN WHAT WE
SEE GO ON ELSEWHERE. WITH THAT, I WENT AHEAD AND ADJUSTED UP POPS
FOR LINCOLN AND NORTHERN MOHAVE COUNTIES INTO THE LATER PORTIONS OF
TONIGHT. THE FLASH FLOOD WATCH WAS EXTENDED FOR THESE AREAS LAST
EVENING FOR THE ONGOING CONVECTION, SO EVEN THOUGH MODELS SHOW
THINGS NOT GET GOING UNTIL BETWEEN 10 AM AND NOON, IT WILL REMAIN
OUT. THE STEERING FLOW TODAY WILL BE STRONGER AND MORE WELL DEFINED
FROM THE SOUTHWEST THAN THE ZIG-ZAG NATURE WE HAD YESTERDAY, AND
THUS WE WILL NEED TO WATCH IN THE LAS VEGAS VALLEY FOR ACTIVITY TO
MOVE IN FROM THE SPRING MOUNTAINS BY LATE THIS MORNING AND INTO THIS
AFTERNOON. THIS COULD PRESENT PROBLEMS WITH THE CARPENTER 1 FIRE
BURN AREA AND WE WILL NEED TO WATCH OUT AGAIN FOR DEBRIS FLOWS.

ELSEWHERE, BOTH THE GFS AND ECMWF AS WELL AS THE HRRR MODEL SUGGEST
THAT ACTIVITY SHOULD GET GOING ACROSS THE SOUTHERN SIERRA, WHITE
MOUNTAINS AS WELL AS MOUNTAINS OF ESMERALDA AND CENTRAL NYE
COUNTIES. ENOUGH INSTABILITY AND CAPE ARE SHOWN THERE AS IS MOISTURE
TO JUSTIFY ADDING THESE AREAS TO THE FLASH FLOOD WATCH, HOWEVER
SINCE ACTIVITY WILL LIKELY TAKE UNTIL LATER THIS MORNING, THE WATCH
WILL START HERE AT 11 AM. AGAIN, THE STEERING FLOW WILL BE FROM THE
SOUTHWEST WHICH COULD DRIVE STORMS THAT DEVELOP ALONG THE SOUTHERN
SIERRA CREST INTO THE OWENS VALLEY LATER THIS AFTERNOON AND THIS
EVENING. WE MAY GET A LITTLE MORE ISSUES WITH WIND HERE AS THERE
WILL BE A LITTLE MORE LOWER LEVEL DRYING THAT TAKES PLACE AND STORMS
MAY GET SOME MOMENTUM AS THEY DROP OFF THE MOUNTAINS AND INTO THE
VALLEYS AND THE AIR ACCELERATES DOWN THE TERRAIN.

TEMPS TODAY SHOULD BE A FEW DEGREES WARMER THAN SATURDAY, EXCEPT
WHERE CLOUDS ARE THICKER AND CONVECTION DEVELOPS EARLIER.

FOR LABOR DAY, THE TROUGH APPROACHING NORCAL WILL KEEP THE FLOW
ALOFT SOUTHWEST TO SOUTH. EVEN THOUGH A LITTLE DRYING TAKES PLACE
ACROSS SOUTHEAST CALIFORNIA, THERE IS STILL ENOUGH MOISTURE AND
INSTABILITY TO KEEP THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
AROUND EVERYWHERE. HOWEVER, THE BEST MOISTURE REMAINS NORTH AND EAST
OF LAS VEGAS, WHICH IS WHERE THE HIGHEST POPS WERE PLACED. HOWEVER,
IT DOES APPEAR THAT THE COVERAGE OF STORMS WILL BE AS GREAT AS WHAT
WE COULD SEE TODAY. WITH A LESS IN THE WAY OF STORMS, THERE COULD BE
MORE SUN AND THUS TEMPS SHOULD BE A LITTLE WARMER.

ONE THING TO WATCH TODAY AND MONDAY WILL BE HOW MUCH ACTIVITY GETS
GOING ON THE MOIST-DRY INTERFACE AS THIS AREA MAY BE MORE ACTIVE
THAN WHAT THE MODELS SHOW. TODAY MAY HELP PROVIDE SOME CLUES AS TO
WHAT WE COULD SEE ALONG THAT INTERFACE TOMORROW.

.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...HIGH PRESSURE WILL
PERSIST ROUGHLY NEAR THE FOUR CORNERS AREA MONDAY NIGHT THROUGH
FRIDAY WITH GENERALLY A SOUTHERLY FLOW OVER THE FORECAST AREA. THIS
WILL KEEP MONSOON MOISTURE IN PLACE WITH ISOLATED TO SCATTERED
THUNDERSTORMS EACH DAY. THE GFS AND ECMWF ARE IN FAIR AGREEMENT FOR
A BIT OF A PATTERN CHANGE BY SATURDAY WITH A LOW PRESSURE SYSTEM
FINALLY MOVING EAST THROUGH THE PACIFIC NORTHWEST. THE RESULT IS A
WEST TO MAYBE EVEN NORTHWEST FLOW OVER THE NORTHERN PART OF THE
FORECAST AREA BRINGING IN DRIER AIR. THIS MAY BRING AN END TO THE
THUNDERSTORM CHANCES FOR THE FAR NORTH AND PARTS OF THE WESTERN CWA.
GUIDANCE CONTINUES TO INDICATE TEMPERATURES A TOUCH ABOVE NORMAL FOR
MOST OF THE LONG TERM.
&&

.AVIATION...FOR MCCARRAN...WINDS WILL FAVOR TYPICAL DIURNAL TRENDS
AWAY FROM ANY SHRA/TSRA THROUGH TONIGHT. SCT-BKN CLOUDS AOA 10-15K
FEET ARE EXPECTED THROUGH TONIGHT. SHRA/TSRA ARE EXPECTED TO DEVELOP
IN AND AROUND THE LAS VEGAS VALLEY AND IN THE APPROACH CORRIDORS ON
TODAY AFTER 18Z AND DIMINISH BETWEEN 04Z AND 07Z MONDAY. GUSTY AND
ERRATIC WINDS...REDUCED CIGS AND VSBY ARE POSSIBLE IN AND NEAR ANY
SHRA/TSRA AND OUTFLOW BOUNDARIES WHICH MAY IMPACT CONFIGURATIONS.
THE FLOW IN THE ATMOSPHERE IS FROM THE SOUTHWEST TO WEST THROUGH
TONIGHT WHICH WOULD FAVOR PUSHING SHRA/TSRA IN FROM THE SPRING
MOUNTAINS TOWARD THE AIRPORT COMPLEX.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...EXPECT SCT-BKN CLOUDS AOA 10-15K FEET WITH WINDS
FAVORING TYPICAL DIURNAL TRENDS THROUGH TONIGHT AWAY FROM ANY
SHRA/TSRA. REDUCED CIGS AND VSBY AND GUSTY AND ERRATIC WINDS IN AND
NEAR SHRA/TSRA WILL BE THE MAIN THREATS. SHRA AND TSRA ARE EXPECTED
AFTER 18Z SUNDAY BEFORE DECREASING AROUND 06Z MONDAY WITH ACTIVITY
MOST LIKELY IN LINCOLN, CLARK, ESMERALDA, MOHAVE, CENTRAL NYE AND
WESTERN INYO COUNTIES. SHRA/TSRA SHOULD MAINLY FROM EAST THROUGH
TONIGHT.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NVZ015-016-018>022.
     FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR NVZ014.
AZ...FLASH FLOOD WATCH THROUGH THIS EVENING FOR AZZ001>003-036.
CA...FLASH FLOOD WATCH FROM 11 AM PDT THIS MORNING THROUGH THIS
     EVENING FOR CAZ519>521.
&&

$$

STACHELSKI/HARRISON

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER






AREA FORECAST DISCUSSION...UPDATED

NWS ALBUQUERQUE NM

 1140 AM MDT SUN SEP 1 2013

.AVIATION...
18Z TAF CYCLE
MORE CONVECTIVE ACTIVITY EXPECTED TODAY AS BACKDOOR SFC FRONT
GETS STORMS GOING ERN PLAINS AND CENTRAL MTNS EARLY THIS AFTERNOON AND
STORMS AND SFC FRONT DEVELOP WWD INTO RG VALLEY LATE THIS AFTN AND
INTO WRN NM THIS EVENING/TONIGHT. ISOLD TO WDLY SCT MVFR CIGS/VSBY IN
SHRA/TSRA TO OCCASIONALLY OBSCURE HIGHER TERRAIN. CELL MOVEMENT
WILL BE SLOW AND SOMEWHAT ERRATIC DUE TO UPPER LEVEL HIGH PRESSURE
CENTER OVERHEAD. STORMS IN WRN NM WILL CONTINUE UNTIL BTWN 6Z-9Z
MONDAY AS A SOMEWHAT ORGANIZED LINE DEVELOPS AND PROPAGATES SLOWLY
WWD.

33

&&

.PREV DISCUSSION...324 AM MDT SUN SEP 1 2013...
...SIGNIFICANT UPTICK IN THUNDERSTORMS EXPECTED TODAY AND LABOR
DAY...

COLD FRONT APPEARS TO BE IN NORTHEASTERN CO
STRETCHING OVER THE KS/NE BORDER JUST AFTER 3 AM. THIS BOUNDARY
WILL PLAY A PIVOTAL ROLE IN THE WEATHER OVER NM TODAY AND THE
LABOR DAY HOLIDAY. THE UPPER LEVEL DOME OF HIGH PRESSURE WILL KEEP
A SYMMETRICAL AND STEADY PRESENCE OVER NM TODAY. MODEST...YET
SUFFICIENT MOISTURE IS CURRENTLY IN PLACE OVER THE NORTHERN HALF
OF THE STATE...AND A NOTABLE INCREASE IS EXPECTED OVER THE
NORTH CENTRAL TO NORTHEASTERN ZONES TODAY AS BETTER BOUNDARY LAYER
MOISTURE IS TRANSPORTED IN WITH THE ARRIVAL OF THE FRONTAL
BOUNDARY. DECENT CAPE VALUES OF 800-1500 J/KG WILL SUPPORT HEALTHY
STORM GROWTH AS UPSLOPE FLOW IS EXPLOITED. THERE WILL LIKELY BE
SOME LOCALLY HEAVY RAINFALL AT TIMES...BUT CONFIDENCE IS NOT HIGH
ENOUGH TO SUPPORT A WIDESPREAD FLASH FLOOD WATCH. STEERING FLOW
WILL BE SLUGGISH DUE TO THE LIGHT WINDS ALOFT...BUT A PROGRESSIVE
ADVANCEMENT OF THE FRONT FARTHER SOUTH AND WEST SHOULD KEEP THE
BEST AREA OF FORCING ON THE MOVE. TEMPERATURES WILL TAKE A
SUBSTANTIAL DROP IN THE NORTHEAST WHILE SOME PARTS OF DE
BACA...ROOSEVELT...AND CHAVES COUNTIES FLIRT WITH NEAR RECORD
HIGHS WHERE THE FRONT WILL NOT YET HAVE ARRIVED.

LATE THIS AFTERNOON AND INTO TONIGHT A MODERATE GAP/CANYON WIND IS
EXPECTED TO DEVELOP...PRIMARILY DOWNWIND OF THE TAOS
CANYON...GLORIETA PASS...AND TIJERAS CANYON. WINDS APPEAR TO STAY
MORE SOUTHEASTERLY FARTHER TO THE SOUTH. GUSTS OF 25 TO 35 MPH
SEEM TO FIT THE BILL WITH CONVECTIVE BURSTS POTENTIALLY ENHANCING
THESE SPEEDS BRIEFLY. THE FRONT IS DEPICTED AS ADVANCING AS FAR
WEST AS THE SAN JUAN BASIN OF NORTHWEST NM BEFORE DAWN ON LABOR
DAY...BUT IT DOES NOT APPEAR TO ADVANCE VERY FAR TO THE
SOUTH...SOMEWHERE NEAR OR JUST SLIGHTLY SOUTH OF I-40.

WHERE THE FRONT GETS HUNG UP IN THE NORTHWESTERN TO WEST CENTRAL
ZONES WILL DICTATE THE THUNDERSTORM CROP FOR LABOR DAY. HAVE
CONTINUED WITH LIKELY POPS THERE...ASSUMING THE FLUX OF BETTER
BOUNDARY LAYER MOISTURE WILL SURVIVE THE TREK THERE. FOR THE
SECOND DAY IN A ROW THE MODELS CONTINUE TO HAMMER THE CENTRAL
MOUNTAIN CHAIN AND ADJACENT HIGHLANDS/HIGH PLAINS TO THE EAST WITH
SYNOPTIC SOUTHEASTERLY SURFACE FLOW AND SUFFICIENT CAPE VALUES OF
400-1000 J/KG. HAVE PAINTED LIKELY POPS ACROSS THE CENTRAL
MOUNTAIN CHAIN BASED ON THIS...TAPERING OFF AS ONE PROGRESSES EAST
TOWARD TX.

TUESDAY`S STORMS WILL BE BASED ON A PROCESS OF RECYCLING REMNANT
MOISTURE FROM MONDAY. WOULD EXPECT A LOWER COVERAGE OVERALL WITH
THE WESTERN TWO THIRDS FAVORED AS THE UPPER HIGH STRENGTHENS INTO
CO. THIS TREND CARRIES ON INTO WEDNESDAY WITH H5 HEIGHTS CLIMBING
TO 596 DAM IN CO. THE HIGH EVENTUALLY DRIFTS BACK INTO NM BY NEXT
WEEKEND WITH A DIURNAL RECYCLING OF MOISTURE PERSISTING. THE HIGH
WILL THUS FIGHT OFF THE WESTERLIES ALOFT...KEEPING AVAILABLE
MOISTURE FROM ESCAPING PREMATURELY...HOWEVER THE ADVERTISED
ORIENTATION OF THE HIGH ALSO WOULD NOT BE SUSCEPTIBLE TO ANY DEEP
SUBTROPICAL MOISTURE INTRUSIONS.

52

.FIRE WEATHER...
UPPER HIGH CENTER LOCATED OVER CENTRAL NM EARLY THIS MORNING AND
FORECAST TO WANDER SLIGHTLY TO THE WEST AND NORTH...BUT STILL REMAINING
SQUARELY OVER THE STATE THIS AFTERNOON AND THROUGH LABOR DAY.

WIND SHIFT APPARENTLY ASSOCIATED WITH EARLIER CONVECTION OVER SW KS
STILL CHUGGING SOUTH INTO PORTIONS OF THE EAST CENTRAL PLAINS ATTM.
NOT CONFIDENT THIS IS THE FRONT FORECAST TO IMPACT THE NORTHEAST
LATER THIS MORNING...AS THE RUC13 SHOWS OTHERWISE...DEPICTING
ANOTHER PUSH AROUND MIDDAY. STILL IT HAS SHOVED SOME 50S DEWPOINTS
BACK INTO THE REGION AFTER THEY DRIED/MIXED OUT SATURDAY AFTERNOON.
NORTHEAST QUARTER OF NM STILL FAVORED FOR BEST WETTING RAIN CHANCES
TODAY...SPREADING WESTWARD TONIGHT AS AN EASTERLY WIND BREAKS INTO
THE UPPER/MIDDLE RGV AND REACHES THE JEMEZ. STORM MOTION TO BE
RATHER SLOW SO POTENTIAL FOR LOCALLY HEAVY RAIN EXISTS. HIGHS TODAY TO
REMAIN ABOVE AVERAGE...WITH NEAR RECORD HIGHS POSSIBLE IN PORTIONS
OF THE EAST CENTRAL PLAINS. GENLY GOOD OR BETTER OVERNIGHT RH
RECOVERIES ANTICIPATED.

CHANCES FOR WETTING RAIN ON LABOR DAY WILL BE FOCUSED OVER THE
CENTRAL MT CHAIN AND ALONG AND EAST OF THE CONTDVD. HIGHS WILL BE A
BIT COOLER BUT STILL ABOVE AVERAGE. STORM MOTION TO BE SLOW...SO
SOME CELLS COULD PRODUCE LOCALLY HEAVY RAIN. SOME POCKETS OF FAIR TO
POOR VENTILATION LIKELY OVER THE WEST AND NORTH.

A DRYING TREND IS STILL FORECAST FOR THE TUESDAY THROUGH FRIDAY
PERIOD. MAINLY DIURNAL SHOWERS AND STORMS ARE FEATURED STARTING
WEDNESDAY OVER THE NORTHERN AND WESTERN HIGH TERRAIN AS THE UPPER
HIGH CENTER WANDERS INTO COLORADO. DESPITE THE DRYING
TREND...OVERNIGHT RECOVERIES SHOULD REMAIN GOOD FOR MOST LOCALES.
AREAS OF FAIR TO POOR VENTILATION RATES ARE FORECAST FOR THE CENTRAL
AND WEST TUESDAY...WITH SOME IMPROVEMENT WEDNESDAY AND THURSDAY.
WIDESPREAD POOR RATES ARE INDICATED FRIDAY FOR THE CENTRAL AND WEST.
HIGH TEMPERATURES REMAIN NEAR TO ABOVE AVERAGE ACROSS NRN AND
CENTRAL NM.

&&

.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SHY









AREA FORECAST DISCUSSION

NWS ALBUQUERQUE NM

 534 AM MDT SUN SEP 1 2013

.AVIATION...
12Z TAF CYCLE
ISOLD -SHRA AND POSSIBLY -TSRA LINGERING OVER ERN NM BEFORE 18Z
WILL BECOME MORE NUMEROUS AS WELL AS DEVELOP OVER THE WRN HIGH
TERRAIN THEREAFTER AS SURFACE FRONT PUSHES INTO NE NM AND THEN
SOUTH AND WWD...REACHING THE CENTRAL MT CHAIN BY 23Z. ISOLD TO
WDLY SCT MVFR CIGS/VSBY IN SHRA/TSRA TO OCCASIONALLY OBSCURE
HIGHER TERRAIN. CELL MOVEMENT TO BE SLOW AND OCCASIONALLY ERRATIC
DUE TO UPPER HIGH PRESSURE CENTER OVERHEAD.

&&

.PREV DISCUSSION...324 AM MDT SUN SEP 1 2013...
...SIGNIFICANT UPTICK IN THUNDERSTORMS EXPECTED TODAY AND LABOR
DAY...

COLD FRONT APPEARS TO BE IN NORTHEASTERN CO
STRETCHING OVER THE KS/NE BORDER JUST AFTER 3 AM. THIS BOUNDARY
WILL PLAY A PIVOTAL ROLE IN THE WEATHER OVER NM TODAY AND THE
LABOR DAY HOLIDAY. THE UPPER LEVEL DOME OF HIGH PRESSURE WILL KEEP
A SYMMETRICAL AND STEADY PRESENCE OVER NM TODAY. MODEST...YET
SUFFICIENT MOISTURE IS CURRENTLY IN PLACE OVER THE NORTHERN HALF
OF THE STATE...AND A NOTABLE INCREASE IS EXPECTED OVER THE
NORTH CENTRAL TO NORTHEASTERN ZONES TODAY AS BETTER BOUNDARY LAYER
MOISTURE IS TRANSPORTED IN WITH THE ARRIVAL OF THE FRONTAL
BOUNDARY. DECENT CAPE VALUES OF 800-1500 J/KG WILL SUPPORT HEALTHY
STORM GROWTH AS UPSLOPE FLOW IS EXPLOITED. THERE WILL LIKELY BE
SOME LOCALLY HEAVY RAINFALL AT TIMES...BUT CONFIDENCE IS NOT HIGH
ENOUGH TO SUPPORT A WIDESPREAD FLASH FLOOD WATCH. STEERING FLOW
WILL BE SLUGGISH DUE TO THE LIGHT WINDS ALOFT...BUT A PROGRESSIVE
ADVANCEMENT OF THE FRONT FARTHER SOUTH AND WEST SHOULD KEEP THE
BEST AREA OF FORCING ON THE MOVE. TEMPERATURES WILL TAKE A
SUBSTANTIAL DROP IN THE NORTHEAST WHILE SOME PARTS OF DE
BACA...ROOSEVELT...AND CHAVES COUNTIES FLIRT WITH NEAR RECORD
HIGHS WHERE THE FRONT WILL NOT YET HAVE ARRIVED.

LATE THIS AFTERNOON AND INTO TONIGHT A MODERATE GAP/CANYON WIND IS
EXPECTED TO DEVELOP...PRIMARILY DOWNWIND OF THE TAOS
CANYON...GLORIETA PASS...AND TIJERAS CANYON. WINDS APPEAR TO STAY
MORE SOUTHEASTERLY FARTHER TO THE SOUTH. GUSTS OF 25 TO 35 MPH
SEEM TO FIT THE BILL WITH CONVECTIVE BURSTS POTENTIALLY ENHANCING
THESE SPEEDS BRIEFLY. THE FRONT IS DEPICTED AS ADVANCING AS FAR
WEST AS THE SAN JUAN BASIN OF NORTHWEST NM BEFORE DAWN ON LABOR
DAY...BUT IT DOES NOT APPEAR TO ADVANCE VERY FAR TO THE
SOUTH...SOMEWHERE NEAR OR JUST SLIGHTLY SOUTH OF I-40.

WHERE THE FRONT GETS HUNG UP IN THE NORTHWESTERN TO WEST CENTRAL
ZONES WILL DICTATE THE THUNDERSTORM CROP FOR LABOR DAY. HAVE
CONTINUED WITH LIKELY POPS THERE...ASSUMING THE FLUX OF BETTER
BOUNDARY LAYER MOISTURE WILL SURVIVE THE TREK THERE. FOR THE
SECOND DAY IN A ROW THE MODELS CONTINUE TO HAMMER THE CENTRAL
MOUNTAIN CHAIN AND ADJACENT HIGHLANDS/HIGH PLAINS TO THE EAST WITH
SYNOPTIC SOUTHEASTERLY SURFACE FLOW AND SUFFICIENT CAPE VALUES OF
400-1000 J/KG. HAVE PAINTED LIKELY POPS ACROSS THE CENTRAL
MOUNTAIN CHAIN BASED ON THIS...TAPERING OFF AS ONE PROGRESSES EAST
TOWARD TX.

TUESDAY`S STORMS WILL BE BASED ON A PROCESS OF RECYCLING REMNANT
MOISTURE FROM MONDAY. WOULD EXPECT A LOWER COVERAGE OVERALL WITH
THE WESTERN TWO THIRDS FAVORED AS THE UPPER HIGH STRENGTHENS INTO
CO. THIS TREND CARRIES ON INTO WEDNESDAY WITH H5 HEIGHTS CLIMBING
TO 596 DAM IN CO. THE HIGH EVENTUALLY DRIFTS BACK INTO NM BY NEXT
WEEKEND WITH A DIURNAL RECYCLING OF MOISTURE PERSISTING. THE HIGH
WILL THUS FIGHT OFF THE WESTERLIES ALOFT...KEEPING AVAILABLE
MOISTURE FROM ESCAPING PREMATURELY...HOWEVER THE ADVERTISED
ORIENTATION OF THE HIGH ALSO WOULD NOT BE SUSCEPTIBLE TO ANY DEEP
SUBTROPICAL MOISTURE INTRUSIONS.

52

&&

.FIRE WEATHER...
UPPER HIGH CENTER LOCATED OVER CENTRAL NM EARLY THIS MORNING AND
FORECAST TO WANDER SLIGHTLY TO THE WEST AND NORTH...BUT STILL REMAINING
SQUARELY OVER THE STATE THIS AFTERNOON AND THROUGH LABOR DAY.

WIND SHIFT APPARENTLY ASSOCIATED WITH EARLIER CONVECTION OVER SW KS
STILL CHUGGING SOUTH INTO PORTIONS OF THE EAST CENTRAL PLAINS ATTM.
NOT CONFIDENT THIS IS THE FRONT FORECAST TO IMPACT THE NORTHEAST
LATER THIS MORNING...AS THE RUC13 SHOWS OTHERWISE...DEPICTING
ANOTHER PUSH AROUND MIDDAY. STILL IT HAS SHOVED SOME 50S DEWPOINTS
BACK INTO THE REGION AFTER THEY DRIED/MIXED OUT SATURDAY AFTERNOON.
NORTHEAST QUARTER OF NM STILL FAVORED FOR BEST WETTING RAIN CHANCES
TODAY...SPREADING WESTWARD TONIGHT AS AN EASTERLY WIND BREAKS INTO
THE UPPER/MIDDLE RGV AND REACHES THE JEMEZ. STORM MOTION TO BE
RATHER SLOW SO POTENTIAL FOR LOCALLY HEAVY RAIN EXISTS. HIGHS TODAY TO
REMAIN ABOVE AVERAGE...WITH NEAR RECORD HIGHS POSSIBLE IN PORTIONS
OF THE EAST CENTRAL PLAINS. GENLY GOOD OR BETTER OVERNIGHT RH
RECOVERIES ANTICIPATED.

CHANCES FOR WETTING RAIN ON LABOR DAY WILL BE FOCUSED OVER THE
CENTRAL MT CHAIN AND ALONG AND EAST OF THE CONTDVD. HIGHS WILL BE A
BIT COOLER BUT STILL ABOVE AVERAGE. STORM MOTION TO BE SLOW...SO
SOME CELLS COULD PRODUCE LOCALLY HEAVY RAIN. SOME POCKETS OF FAIR TO
POOR VENTILATION LIKELY OVER THE WEST AND NORTH.

A DRYING TREND IS STILL FORECAST FOR THE TUESDAY THROUGH FRIDAY
PERIOD. MAINLY DIURNAL SHOWERS AND STORMS ARE FEATURED STARTING
WEDNESDAY OVER THE NORTHERN AND WESTERN HIGH TERRAIN AS THE UPPER
HIGH CENTER WANDERS INTO COLORADO. DESPITE THE DRYING
TREND...OVERNIGHT RECOVERIES SHOULD REMAIN GOOD FOR MOST LOCALES.
AREAS OF FAIR TO POOR VENTILATION RATES ARE FORECAST FOR THE CENTRAL
AND WEST TUESDAY...WITH SOME IMPROVEMENT WEDNESDAY AND THURSDAY.
WIDESPREAD POOR RATES ARE INDICATED FRIDAY FOR THE CENTRAL AND WEST.
HIGH TEMPERATURES REMAIN NEAR TO ABOVE AVERAGE ACROSS NRN AND
CENTRAL NM.

&&

.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$








AREA FORECAST DISCUSSION

NWS ALBUQUERQUE NM

 324 AM MDT SUN SEP 1 2013

...SIGNIFICANT UPTICK IN THUNDERSTORMS EXPECTED TODAY AND LABOR
DAY...

.DISCUSSION...COLD FRONT APPEARS TO BE IN NORTHEASTERN CO
STRETCHING OVER THE KS/NE BORDER JUST AFTER 3 AM. THIS BOUNDARY
WILL PLAY A PIVOTAL ROLE IN THE WEATHER OVER NM TODAY AND THE
LABOR DAY HOLIDAY. THE UPPER LEVEL DOME OF HIGH PRESSURE WILL KEEP
A SYMMETRICAL AND STEADY PRESENCE OVER NM TODAY. MODEST...YET
SUFFICIENT MOISTURE IS CURRENTLY IN PLACE OVER THE NORTHERN HALF
OF THE STATE...AND A NOTABLE INCREASE IS EXPECTED OVER THE
NORTH CENTRAL TO NORTHEASTERN ZONES TODAY AS BETTER BOUNDARY LAYER
MOISTURE IS TRANSPORTED IN WITH THE ARRIVAL OF THE FRONTAL
BOUNDARY. DECENT CAPE VALUES OF 800-1500 J/KG WILL SUPPORT HEALTHY
STORM GROWTH AS UPSLOPE FLOW IS EXPLOITED. THERE WILL LIKELY BE
SOME LOCALLY HEAVY RAINFALL AT TIMES...BUT CONFIDENCE IS NOT HIGH
ENOUGH TO SUPPORT A WIDESPREAD FLASH FLOOD WATCH. STEERING FLOW
WILL BE SLUGGISH DUE TO THE LIGHT WINDS ALOFT...BUT A PROGRESSIVE
ADVANCEMENT OF THE FRONT FARTHER SOUTH AND WEST SHOULD KEEP THE
BEST AREA OF FORCING ON THE MOVE. TEMPERATURES WILL TAKE A
SUBSTANTIAL DROP IN THE NORTHEAST WHILE SOME PARTS OF DE
BACA...ROOSEVELT...AND CHAVES COUNTIES FLIRT WITH NEAR RECORD
HIGHS WHERE THE FRONT WILL NOT YET HAVE ARRIVED.

LATE THIS AFTERNOON AND INTO TONIGHT A MODERATE GAP/CANYON WIND IS
EXPECTED TO DEVELOP...PRIMARILY DOWNWIND OF THE TAOS
CANYON...GLORIETA PASS...AND TIJERAS CANYON. WINDS APPEAR TO STAY
MORE SOUTHEASTERLY FARTHER TO THE SOUTH. GUSTS OF 25 TO 35 MPH
SEEM TO FIT THE BILL WITH CONVECTIVE BURSTS POTENTIALLY ENHANCING
THESE SPEEDS BRIEFLY. THE FRONT IS DEPICTED AS ADVANCING AS FAR
WEST AS THE SAN JUAN BASIN OF NORTHWEST NM BEFORE DAWN ON LABOR
DAY...BUT IT DOES NOT APPEAR TO ADVANCE VERY FAR TO THE
SOUTH...SOMEWHERE NEAR OR JUST SLIGHTLY SOUTH OF I-40.

WHERE THE FRONT GETS HUNG UP IN THE NORTHWESTERN TO WEST CENTRAL
ZONES WILL DICTATE THE THUNDERSTORM CROP FOR LABOR DAY. HAVE
CONTINUED WITH LIKELY POPS THERE...ASSUMING THE FLUX OF BETTER
BOUNDARY LAYER MOISTURE WILL SURVIVE THE TREK THERE. FOR THE
SECOND DAY IN A ROW THE MODELS CONTINUE TO HAMMER THE CENTRAL
MOUNTAIN CHAIN AND ADJACENT HIGHLANDS/HIGH PLAINS TO THE EAST WITH
SYNOPTIC SOUTHEASTERLY SURFACE FLOW AND SUFFICIENT CAPE VALUES OF
400-1000 J/KG. HAVE PAINTED LIKELY POPS ACROSS THE CENTRAL
MOUNTAIN CHAIN BASED ON THIS...TAPERING OFF AS ONE PROGRESSES EAST
TOWARD TX.

TUESDAY`S STORMS WILL BE BASED ON A PROCESS OF RECYCLING REMNANT
MOISTURE FROM MONDAY. WOULD EXPECT A LOWER COVERAGE OVERALL WITH
THE WESTERN TWO THIRDS FAVORED AS THE UPPER HIGH STRENGTHENS INTO
CO. THIS TREND CARRIES ON INTO WEDNESDAY WITH H5 HEIGHTS CLIMBING
TO 596 DAM IN CO. THE HIGH EVENTUALLY DRIFTS BACK INTO NM BY NEXT
WEEKEND WITH A DIURNAL RECYCLING OF MOISTURE PERSISTING. THE HIGH
WILL THUS FIGHT OFF THE WESTERLIES ALOFT...KEEPING AVAILABLE
MOISTURE FROM ESCAPING PREMATURELY...HOWEVER THE ADVERTISED
ORIENTATION OF THE HIGH ALSO WOULD NOT BE SUSCEPTIBLE TO ANY DEEP
SUBTROPICAL MOISTURE INTRUSIONS.

52

&&

.FIRE WEATHER...
UPPER HIGH CENTER LOCATED OVER CENTRAL NM EARLY THIS MORNING AND
FORECAST TO WANDER SLIGHTLY TO THE WEST AND NORTH...BUT STILL REMAINING
SQUARELY OVER THE STATE THIS AFTERNOON AND THROUGH LABOR DAY.

WIND SHIFT APPARENTLY ASSOCIATED WITH EARLIER CONVECTION OVER SW KS
STILL CHUGGING SOUTH INTO PORTIONS OF THE EAST CENTRAL PLAINS ATTM.
NOT CONFIDENT THIS IS THE FRONT FORECAST TO IMPACT THE NORTHEAST
LATER THIS MORNING...AS THE RUC13 SHOWS OTHERWISE...DEPICTING
ANOTHER PUSH AROUND MIDDAY. STILL IT HAS SHOVED SOME 50S DEWPOINTS
BACK INTO THE REGION AFTER THEY DRIED/MIXED OUT SATURDAY AFTERNOON.
NORTHEAST QUARTER OF NM STILL FAVORED FOR BEST WETTING RAIN CHANCES
TODAY...SPREADING WESTWARD TONIGHT AS AN EASTERLY WIND BREAKS INTO
THE UPPER/MIDDLE RGV AND REACHES THE JEMEZ. STORM MOTION TO BE
RATHER SLOW SO POTENTIAL FOR LOCALLY HEAVY RAIN EXISTS. HIGHS TODAY TO
REMAIN ABOVE AVERAGE...WITH NEAR RECORD HIGHS POSSIBLE IN PORTIONS
OF THE EAST CENTRAL PLAINS. GENLY GOOD OR BETTER OVERNIGHT RH
RECOVERIES ANTICIPATED.

CHANCES FOR WETTING RAIN ON LABOR DAY WILL BE FOCUSED OVER THE
CENTRAL MT CHAIN AND ALONG AND EAST OF THE CONTDVD. HIGHS WILL BE A
BIT COOLER BUT STILL ABOVE AVERAGE. STORM MOTION TO BE SLOW...SO
SOME CELLS COULD PRODUCE LOCALLY HEAVY RAIN. SOME POCKETS OF FAIR TO
POOR VENTILATION LIKELY OVER THE WEST AND NORTH.

A DRYING TREND IS STILL FORECAST FOR THE TUESDAY THROUGH FRIDAY
PERIOD. MAINLY DIURNAL SHOWERS AND STORMS ARE FEATURED STARTING
WEDNESDAY OVER THE NORTHERN AND WESTERN HIGH TERRAIN AS THE UPPER
HIGH CENTER WANDERS INTO COLORADO. DESPITE THE DRYING
TREND...OVERNIGHT RECOVERIES SHOULD REMAIN GOOD FOR MOST LOCALES.
AREAS OF FAIR TO POOR VENTILATION RATES ARE FORECAST FOR THE CENTRAL
AND WEST TUESDAY...WITH SOME IMPROVEMENT WEDNESDAY AND THURSDAY.
WIDESPREAD POOR RATES ARE INDICATED FRIDAY FOR THE CENTRAL AND WEST.
HIGH TEMPERATURES REMAIN NEAR TO ABOVE AVERAGE ACROSS NRN AND
CENTRAL NM.

&&

.AVIATION...
06Z TAF CYCLE
ISOLD -SHRA AND POSSIBLY A -TSRA WILL LINGER INTO THE LATE NIGHT
HOURS MAINLY NORTH OF I-40 AND EAST OF HIGHWAY 550 TO THE BORDER
WITH TX/OK. A BACK DOOR COLD FRONT WILL SAG INTO THE NE PLAINS
TONIGHT AND THE REST OF THE EASTERN PLAINS ON SUNDAY...BEFORE
PUSHING THROUGH GAPS IN THE CENTRAL MOUNTAIN CHAIN WITH A SOMEWHAT
GUSTY E CANYON WIND IN THE RIO GRANDE VALLEY LATE SUNDAY AFTN INTO
THE NIGHT. THE FRONT WILL BRING MOISTURE AND A TRIGGER FOR TS AND
SHRA WITH MORE WDSPRD CONVECTION SUNDAY AFTN AND EVENING. WITH
THE FRONT PROGRESSING UP THE EAST SLOPES OF THE CONTDVD...THE
CONTDVD REGION COULD REMAIN ACTIVE WITH STORMS INTO THE LATE NIGHT
HOURS.

44

&&

.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON......................  90  65  90  62 /  20  40  20  20
DULCE...........................  83  51  80  51 /  40  50  50  40
CUBA............................  85  56  82  54 /  50  40  60  60
GALLUP..........................  86  57  86  55 /  20  40  40  40
EL MORRO........................  84  54  82  52 /  30  50  60  50
GRANTS..........................  88  57  85  54 /  40  50  60  50
QUEMADO.........................  86  57  85  55 /  40  40  50  50
GLENWOOD........................  90  62  89  61 /  20  20  30  30
CHAMA...........................  80  47  79  45 /  50  60  60  60
LOS ALAMOS......................  86  58  83  56 /  50  40  50  50
PECOS...........................  83  56  81  55 /  60  60  60  60
CERRO/QUESTA....................  79  51  77  49 /  70  50  60  50
RED RIVER.......................  69  40  66  41 /  80  60  70  60
ANGEL FIRE......................  74  39  72  39 /  80  60  70  60
TAOS............................  83  55  81  52 /  50  50  50  50
MORA............................  78  53  74  51 /  70  70  60  60
ESPANOLA........................  91  60  87  59 /  40  30  40  40
SANTA FE........................  87  59  83  57 /  50  40  50  50
SANTA FE AIRPORT................  91  60  86  59 /  40  30  40  40
ALBUQUERQUE FOOTHILLS...........  91  66  87  64 /  40  30  40  40
ALBUQUERQUE HEIGHTS.............  93  70  89  69 /  30  30  30  40
ALBUQUERQUE VALLEY..............  95  64  91  62 /  20  30  30  40
ALBUQUERQUE WEST MESA...........  95  65  90  65 /  20  30  30  40
LOS LUNAS.......................  96  67  93  65 /  20  30  30  40
RIO RANCHO......................  94  68  90  67 /  30  30  30  40
SOCORRO.........................  95  67  91  66 /  20  20  20  30
SANDIA PARK/CEDAR CREST.........  85  54  82  55 /  50  50  50  50
TIJERAS.........................  89  59  85  58 /  50  40  50  40
MORIARTY/ESTANCIA...............  91  56  87  56 /  50  30  50  50
CLINES CORNERS..................  85  58  80  58 /  60  60  70  60
GRAN QUIVIRA....................  88  60  82  59 /  40  30  40  50
CARRIZOZO.......................  91  61  86  59 /  30  20  40  40
RUIDOSO.........................  82  56  74  53 /  30  40  60  60
CAPULIN.........................  82  54  80  53 /  70  50  50  40
RATON...........................  84  56  81  55 /  60  50  50  40
SPRINGER........................  88  56  83  56 /  70  50  50  40
LAS VEGAS.......................  84  55  79  55 /  70  70  50  50
CLAYTON.........................  90  62  86  63 /  50  40  30  20
ROY.............................  88  60  82  61 /  60  50  50  40
CONCHAS.........................  94  66  89  66 /  50  50  40  40
SANTA ROSA......................  94  65  87  64 /  40  50  40  40
TUCUMCARI.......................  96  66  89  65 /  50  50  40  30
CLOVIS..........................  94  64  86  63 /  20  40  40  30
PORTALES........................  94  67  87  64 /  20  30  40  30
FORT SUMNER.....................  95  67  89  65 /  30  40  40  40
ROSWELL.........................  98  69  91  67 /  10  20  40  40
PICACHO.........................  92  64  86  62 /  20  20  40  50
ELK.............................  86  60  79  57 /  20  20  50  60

&&

.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

52






AREA FORECAST DISCUSSION

NWS RALEIGH NC

 757 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 /00Z TUESDAY THROUGH SATURDAY/...
AS OF 755 PM MONDAY...

24-HR TAF PERIOD:
A FEW LINGERING SHOWERS ACROSS THE EAST SHOULD COME TO AN END OVER
THE NEXT COUPLE HOURS...WITH SKIES SCATTERING/CLEARING OVERNIGHT.
GIVEN THE GOOD LOW LEVEL MOISTURE EXPECTED...THERE IS A POTENTIAL
FOR SUB VFR FOG/STRATUS ONCE AGAIN EARLY TUESDAY MORNING (08-14Z).
THERE IS A CHANCE OF SHOWERS/STORMS ACROSS THE EASTERN TERMINALS
(KRDU/KFAY/KRWI) ON TUESDAY AHEAD OF A COLD FRONT EXPECTED TO MOVE
FROM NW TO SE ACROSS CENTRAL NC DURING THE AFTERNOON/EVENING. -KC

LOOKING AHEAD:
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...KC/VINCENT









AREA FORECAST DISCUSSION

NWS RALEIGH NC

 246 PM EDT SUN SEP 1 2013

.SYNOPSIS...
A WARM AND MOIST SOUTHERLY FLOW WILL PERSIST THROUGH MONDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST MONDAY NIGHT...
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 1230 PM SUNDAY...

UPPER LEVEL DISTURBANCES WILL TRAVERSE THE REGION IN STRENGTHENING
CYCLONIC FLOW ALOFT THIS AFT/EVE...IN THE PRESENCE OF MODERATE
INSTABILITY (MLCAPE 1500-2000 J/KG) ASSOC/W STRONG INSOLATION AND A
VERY MOIST LOW-LEVEL AIRMASS. AS OF 16Z...ISOLATED TO SCATTERED
CONVECTION HAS DEVELOPED ALONG THE HIGHWAY 1 IN ASSOCIATION WITH
STRONG INSOLATION /RAPID EROSION OF CINH/ AND A SMALL AMPLITUDE
DISTURBANCE ALOFT PER WV IMAGERY AND RAP DATA. EXPECT THE BEST
CHANCE FOR CONVECTION THIS AFTERNOON EAST OF THE HIGHWAY 1 CORRIDOR
AS THE AFOREMENTIONED DISTURBANCE TRACKS SLOWLY EAST TOWARD THE
COAST...FOLLOWED BY INCREASING CHANCES IN THE WESTERN PIEDMONT BY
LATE THIS AFTERNOON THROUGH THIS EVENING AS A SMALL AMPLITUDE WAVE
(IN EASTERN KY AT 16Z) TRACKS SLOWLY EAST IN VICINITY OF THE
NORTHWEST NC AND SOUTHWEST VA BORDER. DESPITE MODERATE
INSTABILITY...GIVEN WEAK DEEP LAYER SHEAR (<= 20 KT)...WEAK TO
MARGINAL DCAPE (500-1000 J/KG) AND WEAK MID-LEVEL LAPSE RATES...FEEL
THAT THE POTENTIAL FOR AN ISOLD SVR STORM IS TOO LOW TO WARRANT
MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. A SLIGHT
CHANCE OF SHOWERS WILL LIKELY PERSIST OVERNIGHT GIVEN EXCELLENT DEEP
LAYER MOISTURE AND MARGINAL NOCTURNAL INSTABILITY IN THE PRESENCE OF
CYCLONIC FLOW ALOFT...WITH THE RELATIVE BEST CHANCE NEAR THE VA
BORDER WHERE DPVA APPEARS MORE LIKELY. EXPECT HIGHS IN THE UPPER 80S
TO LOWER 90S...OR 87-92F...HIGHEST IN THE COASTAL PLAIN. LOWS
TONIGHT IN THE LOWER TO MID 70S...OR 70-74F. -VINCENT

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 245 PM SUNDAY...

OVERVIEW:
CYCLONIC FLOW ALOFT WILL FURTHER STRENGTHEN ACROSS THE MID-
ATLANTIC AND CAROLINAS ON MON/MON NIGHT AS AN UPPER LEVEL LOW
AMPLIFIES ACROSS THE NORTHERN GREAT LAKES. AN ATTENDANT SFC LOW
WILL BE PRESENT ACROSS THE LOWER GREAT LAKES AND NORTHERN MID-
ATLANTIC...WITH A COLD FRONT EXTENDING SOUTHWEST FROM THE OH
VALLEY INTO THE LOWER MS RIVER VALLEY. THE COLD FRONT WILL
APPROACH THE SOUTHERN APPALACHIANS FROM THE NORTHWEST BY 12Z TUE.

PRECIP CHANCES:
EXPECT A THERMODYNAMIC ENVIRONMENT LARGELY SIMILAR TO TODAY ON MON
AFT/EVE...WITH THE POSSIBLE EXCEPTION OF SLIGHTLY STEEPER MID-
LEVEL LAPSE RATES ON THE ORDER OF 6.0-6.5 C/KM IN ADDITION TO A DRIER
MID-LEVEL AIRMASS...WHICH SHOULD CONTRIBUTE TO MLCAPE VALUES OF
1500-2500 J/KG AND DCAPE OF 1000-1250 J/KG AT PEAK HEATING.
FORCING FOR ASCENT MON AFT/EVE WILL CONSIST OF WEAK/SHALLOW LOW-
LEVEL CONVERGENCE ASSOCIATED WITH A SHARPENING LEE TROUGH...AND
DPVA ASSOC/W SMALL AMPLITUDE DISTURBANCES IN CYCLONIC FLOW
ALOFT...WHICH SHOULD BE MORE THAN ENOUGH TO RESULT IN SCATTERED TO
WIDESPREAD CONVECTION GIVEN MODERATE DIURNAL DESTABILIZATION AND
DEEP MOISTURE WITH PWAT VALUES OF ~1.75". THE EXACT TIMING AND
COVERAGE OF CONVECTION REMAINS DIFFICULT TO ASCERTAIN GIVEN THAT
IT WILL HIGHLY DEPEND ON THE PRECISE TIMING OF SMALL AMPLITUDE
DISTURBANCES ALOFT...AND PERHAPS FURTHER COMPLICATED BY THE
REMNANTS OF ANY UPSTREAM MCS ACTIVITY (IF SUCH ACTIVITY DEVELOPS
OVER THE TN VALLEY) LATE TONIGHT AND MONDAY MORNING...SIMILAR TO
THE PAST FEW DAYS. AT THIS TIME WILL MAKE LITTLE CHANGE TO THE
PREVIOUS FCST WITH PRECIP CHANCES ~50%. CHANCES SHOULD DECREASE
WITHIN SEVERAL HOURS AFTER SUNSET...THOUGH A SLIGHT TO LOW CHANCE
OF SHOWERS (PERHAPS AN ISOLD STORM) WILL PERSIST AFTER MIDNIGHT
GIVEN DEEP MOISTURE...MARGINAL NOCTURNAL INSTABILITY AND CYCLONIC
FLOW ALOFT.

TEMPERATURES:
HIGHS ON MON WILL BE SIMILAR TO BUT PERHAPS SLIGHTLY WARMER THAN
TODAY DEPENDING ON CLOUD COVER AND CONVECTION...IN THE UPPER 80S
TO LOWER 90S...OR 88-93F...WARMEST IN THE EAST. LOWS MON NIGHT
ABOVE NORMAL IN THE LOWER TO MID 70S GIVEN CLOUD COVER AND LIGHT
SOUTHERLY FLOW IN ADVANCE OF THE COLD FRONT APPROACHING THE
SOUTHERN APPALACHIANS.

SEVERE THREAT:
THE OVERALL ENVIRONMENT ON MON AFT/EVE WILL BE SIMILAR TO TODAY...
WITH SLIGHTLY STRONGER DEEP LAYER SHEAR (~20 KT) AND...PERHAPS MORE
IMPORTANTLY...SLIGHTLY STEEPER MID-LEVEL LAPSE RATES AND A DRIER
MID-LEVEL AIRMASS THAT WILL CONTRIBUTE TO STRONGER DCAPE DURING
PEAK HEATING. WITH THE ABOVE IN MIND...WILL INCLUDE MENTION IN THE
HAZARDOUS WEATHER OUTLOOK OF A POTENTIAL FOR ISOLD SEVERE STORMS
CAPABLE OF PRODUCING DAMAGING WINDS DURING THE AFT/EVE. IF FORCING
FOR ASCENT IS JUXTAPOSED WELL WITH PEAK HEATING AND DEVELOPMENT IS
LARGELY DELAYED UNTIL MID/LATE AFTERNOON...A BETTER SEVERE WIND
THREAT COULD EMERGE VIA ORGANIZATION ASSOC/W OUTFLOW GIVEN AN
ENVIRONMENT THAT WOULD FAVOR ROBUST COLD POOLS. -VINCENT

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 200 PM SUNDAY...

MORE AND MORE THE LONG TERM IS SHAPING UP TO BE AN EXTENDED PERIOD
OF DRY WEATHER CHARACTERIZED BY NEAR NORMAL TEMPERATURES FOR EARLY
SEPTEMBER. THE BEST CHANCE FOR RAIN COULD BE VERY EARLY ON IN THE
PERIOD AS AN UPPER TROUGH SITS OVER THE EAST COAST WITH A SURFACE
LOW MOVING THROUGH SOUTHERN QUEBEC. ON TUESDAY AFTERNOON THE MAIN
FRONTAL SYSTEM ASSOCIATED WITH THIS LOW SHOULD BE JUST EAST OF THE
CWA WITH REINFORCING BOUNDARY OVER THE APPALACHIANS. GFS FORECAST
SOUNDINGS IN BUFKIT INDICATE THAT AN ELEVATED MIXED LAYER WILL STILL
EXIST BUT WILL BECOME INCREASING CAPPED AS THE DAY GOES ON. THE BEST
CONDITIONS FOR ANY KIND OF SUSTAINED CONVECTION SHOULD BE FROM
FAYETTEVILLE SOUTH AND EAST. BACK TO THE WEST A LARGE SURFACE HIGH
WILL SLOWLY BUILD EASTWARD...ENFORCING MORE STABLE CONDITIONS WITH
TIME. WILL KEEP CHANCE POPS IN THE SOUTHEAST WITH SLIGHT CHANCE BACK
TO THE WEST. THIS SHOULD BE THE HOTTEST DAY OF THE LONG TERM AS THE
FULL EFFECTS OF THE FRONT WILL NOT BE REALIZED UNTIL WEDNESDAY.
HIGHS IN THE UPPER 80S TO NEAR 90 DEGREES. LOWS IN THE LOWER 60S NW
TO UPPER 60S SOUTH.

WEDNESDAY THROUGH FRIDAY CENTRAL NC WILL BE UNDER A DOMINANT SURFACE
HIGH PRESSURE AND A VERY WEAK UPPER LEVEL FLOW REGIME BETWEEN THE
UPPER TROUGH TO THE NORTH AND THE VERY STRONG UPPER HIGH OVER THE
SOUTHWESTERN CONUS. WEATHER SHOULD REMAIN DRY AND HIGHS WILL BE IN
THE MID 80S WITH LOWS IN THE LOW TO MID 60S.

THE STRONG HIGH OVER THE SOUTHWESTERN CONUS WILL BEGIN TO BREAK DOWN
OVER THE WEEKEND AND A WEAK UPPER LEVEL LOW OVER THE DEEP SOUTH WILL
SLOWLY BEGIN TO ADVECT MOISTURE TOWARDS THE SOUTHWESTERN PORTIONS OF
OUR CWA. IT IS VERY POSSIBLE AT THIS POINT THAT THE WEEKEND COULD
REMAIN DRY BUT THE CHANCES FOR PRECIPITATION WILL CERTAINLY BE
GREATER THAN MIDWEEK. WILL CARRY SLIGHT CHANCE POPS SATURDAY AND
SUNDAY AFTERNOON WITH HIGHEST VALUES IN THE SOUTHWEST BUT STILL FEEL
LIKE SURFACE HIGH WILL KEEP WEATHER LARGELY DRY THROUGH THE END OF
THE LONG TERM. MAY SEE A VERY GRADUAL WARMING TOWARDS THE UPPER 80S
BY THE WEEKEND WITH LOWS TRENDING TOWARDS THE UPPER 60S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1200 PM SUNDAY...

24-HR TAF PERIOD:
MVFR/VFR CEILINGS RANGING FROM 1500-4500 FT AGL ARE EXPECTED ACROSS
CENTRAL NC THIS AFTERNOON...WITH THE BEST CHANCE OF MVFR CEILINGS AT
THE INT/GSO TERMINALS THROUGH EARLY/MID AFTERNOON...THEN EQUAL
CHANCES AT ALL TERMINALS MID AFTERNOON THROUGH MIDNIGHT IN ASSOC/W
SCATTERED SHOWERS AND THUNDERSTORMS. SUB-VFR CEILINGS OR FOG WILL BE
POSSIBLE ONCE AGAIN OVERNIGHT...PRIMARILY BETWEEN 06-14Z MONDAY
MORNING.

LOOKING AHEAD:
THE PROBABILITY FOR SHOWERS AND THUNDERSTORMS WILL FURTHER INCREASE
MON AFT/EVE INTO MON NIGHT AT ALL TERMINALS...IN ASSOCIATION WITH
STRENGTHENING CYCLONIC FLOW ALOFT AND A COLD FRONT APPROACHING THE
REGION FROM THE NORTHWEST. THE FRONT IS EXPECTED TO PROGRESS
SOUTHEAST ACROSS CENTRAL NC DURING THE DAY TUE...WITH THE BEST
CHANCE OF SHOWERS AND THUNDERSTORMS SHIFTING TO THE EASTERN
TERMINALS (RDU/FAY/RWI) BY TUE AFTERNOON. ASIDE FROM A CHANCE FOR
FOG NEAR AND JUST PRIOR TO SUNRISE (08-12Z) WED/THU...EXPECT VFR
CONDITIONS IN THE WAKE OF THE FRONT AS HIGH PRESSURE BUILDS INTO THE
REGION. -VINCENT

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...RTE
AVIATION...VINCENT






AREA FORECAST DISCUSSION

NWS RALEIGH NC

 205 PM EDT SUN SEP 01 2013

.SYNOPSIS...
A WARM AND MOIST SOUTHERLY FLOW WILL PERSIST THROUGH MONDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST MONDAY NIGHT...
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 1230 PM SUNDAY...

UPPER LEVEL DISTURBANCES WILL TRAVERSE THE REGION IN STRENGTHENING
CYCLONIC FLOW ALOFT THIS AFT/EVE...IN THE PRESENCE OF MODERATE
INSTABILITY (MLCAPE 1500-2000 J/KG) ASSOC/W STRONG INSOLATION AND A
VERY MOIST LOW-LEVEL AIRMASS. AS OF 16Z...ISOLATED TO SCATTERED
CONVECTION HAS DEVELOPED ALONG THE HIGHWAY 1 IN ASSOCIATION WITH
STRONG INSOLATION /RAPID EROSION OF CINH/ AND A SMALL AMPLITUDE
DISTURBANCE ALOFT PER WV IMAGERY AND RAP DATA. EXPECT THE BEST
CHANCE FOR CONVECTION THIS AFTERNOON EAST OF THE HIGHWAY 1 CORRIDOR
AS THE AFOREMENTIONED DISTURBANCE TRACKS SLOWLY EAST TOWARD THE
COAST...FOLLOWED BY INCREASING CHANCES IN THE WESTERN PIEDMONT BY
LATE THIS AFTERNOON THROUGH THIS EVENING AS A SMALL AMPLITUDE WAVE
(IN EASTERN KY AT 16Z) TRACKS SLOWLY EAST IN VICINITY OF THE
NORTHWEST NC AND SOUTHWEST VA BORDER. DESPITE MODERATE
INSTABILITY...GIVEN WEAK DEEP LAYER SHEAR (<= 20 KT)...WEAK TO
MARGINAL DCAPE (500-1000 J/KG) AND WEAK MID-LEVEL LAPSE RATES...FEEL
THAT THE POTENTIAL FOR AN ISOLD SVR STORM IS TOO LOW TO WARRANT
MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. A SLIGHT
CHANCE OF SHOWERS WILL LIKELY PERSIST OVERNIGHT GIVEN EXCELLENT DEEP
LAYER MOISTURE AND MARGINAL NOCTURNAL INSTABILITY IN THE PRESENCE OF
CYCLONIC FLOW ALOFT...WITH THE RELATIVE BEST CHANCE NEAR THE VA
BORDER WHERE DPVA APPEARS MORE LIKELY. EXPECT HIGHS IN THE UPPER 80S
TO LOWER 90S...OR 87-92F...HIGHEST IN THE COASTAL PLAIN. LOWS
TONIGHT IN THE LOWER TO MID 70S...OR 70-74F. -VINCENT

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...

SHOULD BE ANOTHER FAIRLY ACTIVE DAY. LONGWAVE TROUGHING WILL DIG
DOWN OVER ERN NOAM AS A SHORTWAVE TROUGH FROM SRN ONTARIO THROUGH MI
SWINGS ESE... YIELDING HEIGHT FALLS OF AROUND 20-30 M OVER NC
MON/MON NIGHT. THE COLD FRONT NOW STRETCHING FROM THE UPPER MIDWEST
LOW SSW THROUGH THE CENTRAL PLAINS WILL CONTINUE TO PUSH ESE...
THROUGH THE OH VALLEY MONDAY THEN TO THE APPALACHIANS BY MONDAY
NIGHT... AS THE PRECEDING PIEDMONT TROUGH SHARPENS. THE LOW-MID
LEVEL FLOW FROM THE SW AND WSW WILL ENSURE CONTINUED ABOVE-NORMAL
MOISTURE CONTENT THROUGH THE COLUMN WITH PW VALUES HOLDING AT
1.7-1.8 INCHES FROM THE TRIANGLE EAST/SE... ALTHOUGH THE MORE WNW
DOWNSLOPE FLOW OVER THE NW PIEDMONT IS EXPECTED TO CAUSE PW VALUES
TO DROP BELOW 1.5 IN. MODELS DIFFER CONSIDERABLY WITH THEIR
INSTABILITY... WITH THE NAM DEPICTING LOWER MLCAPE UNDER 2000 J/KG
FROM THE TRIANGLE SOUTH AND EAST WITH 2000-2500 J/KG OVER THE NW
CWA... WHILE THE GFS IS NEARLY OPPOSITE WITH MLCAPE LOW OVER THE NW
AND PEAKING AT 1500-2500 J/KG OVER THE SOUTH AND EAST MONDAY
AFTERNOON. THIS IS LARGELY A REFLECTION OF SURFACE DEW POINTS...
WHICH ARE DIFFICULT TO RESOLVE IN THE MODELS AT THIS RANGE. AS
SUCH... IT IS TOUGH TO DETERMINE THE THREAT OF STRONG STORMS...
ALTHOUGH THE DEEP LAYER BULK SHEAR REMAINS MARGINAL AT JUST 10-15
KTS... WHICH WILL LIMIT STORM ORGANIZATION AND STRENGTH. IN ANY
CASE... WE SHOULD STILL SEE AT LEAST SCATTERED STORMS DEVELOPING BY
AFTERNOON... MOST LIKELY STARTING OUT AS ISOLATED MOUNTAIN
CONVECTION DROPPING TO THE ESE AND CONGEALING INTO A BROKEN LINE OF
COLD POOL DOMINATED STORMS. GFS STATISTICAL GUIDANCE HIGHS APPEAR
TOO WARM GIVEN THAT WE SHOULD SEE QUITE A BIT OF CONVECTIVE DEBRIS
MID/HIGH CLOUDS... AND ITS JUMP IN AFTERNOON THICKNESS (BEYOND 1430
M) IS A VAST DEPARTURE FROM OTHER GUIDANCE. WILL RETAIN HIGHS NEAR
90 TO THE LOWER 90S. LOWS 69-73 WITH PARTLY CLOUDY SKIES AND A
LINGERING ISOLATED SHOWER/STORM CHANCE. -GIH

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...

MORE AND MORE THE LONG TERM IS SHAPING UP TO BE AN EXTENDED PERIOD
OF DRY WEATHER CHARACTERIZED BY NEAR NORMAL TEMPERATURES FOR EARLY
SEPTEMBER. THE BEST CHANCE FOR RAIN COULD BE VERY EARLY ON IN THE
PERIOD AS AN UPPER TROUGH SITS OVER THE EAST COAST WITH A SURFACE
LOW MOVING THROUGH SOUTHERN QUEBEC. ON TUESDAY AFTERNOON THE MAIN
FRONTAL SYSTEM ASSOCIATED WITH THIS LOW SHOULD BE JUST EAST OF THE
CWA WITH REINFORCING BOUNDARY OVER THE APPALACHIANS. GFS FORECAST
SOUNDINGS IN BUFKIT INDICATE THAT AN ELEVATED MIXED LAYER WILL STILL
EXIST BUT WILL BECOME INCREASING CAPPED AS THE DAY GOES ON. THE BEST
CONDITIONS FOR ANY KIND OF SUSTAINED CONVECTION SHOULD BE FROM
FAYETTEVILLE SOUTH AND EAST. BACK TO THE WEST A LARGE SURFACE HIGH
WILL SLOWLY BUILD EASTWARD...ENFORCING MORE STABLE CONDITIONS WITH
TIME. WILL KEEP CHANCE POPS IN THE SOUTHEAST WITH SLIGHT CHANCE BACK
TO THE WEST. THIS SHOULD BE THE HOTTEST DAY OF THE LONG TERM AS THE
FULL EFFECTS OF THE FRONT WILL NOT BE REALIZED UNTIL WEDNESDAY.
HIGHS IN THE UPPER 80S TO NEAR 90 DEGREES. LOWS IN THE LOWER 60S NW
TO UPPER 60S SOUTH.

WEDNESDAY THROUGH FRIDAY CENTRAL NC WILL BE UNDER A DOMINANT SURFACE
HIGH PRESSURE AND A VERY WEAK UPPER LEVEL FLOW REGIME BETWEEN THE
UPPER TROUGH TO THE NORTH AND THE VERY STRONG UPPER HIGH OVER THE
SOUTHWESTERN CONUS. WEATHER SHOULD REMAIN DRY AND HIGHS WILL BE IN
THE MID 80S WITH LOWS IN THE LOW TO MID 60S.

THE STRONG HIGH OVER THE SOUTHWESTERN CONUS WILL BEGIN TO BREAK DOWN
OVER THE WEEKEND AND A WEAK UPPER LEVEL LOW OVER THE DEEP SOUTH WILL
SLOWLY BEGIN TO ADVECT MOISTURE TOWARDS THE SOUTHWESTERN PORTIONS OF
OUR CWA. IT IS VERY POSSIBLE AT THIS POINT THAT THE WEEKEND COULD
REMAIN DRY BUT THE CHANCES FOR PRECIPITATION WILL CERTAINLY BE
GREATER THAN MIDWEEK. WILL CARRY SLIGHT CHANCE POPS SATURDAY AND
SUNDAY AFTERNOON WITH HIGHEST VALUES IN THE SOUTHWEST BUT STILL FEEL
LIKE SURFACE HIGH WILL KEEP WEATHER LARGELY DRY THROUGH THE END OF
THE LONG TERM. MAY SEE A VERY GRADUAL WARMING TOWARDS THE UPPER 80S
BY THE WEEKEND WITH LOWS TRENDING TOWARDS THE UPPER 60S.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1200 PM SUNDAY...

24-HR TAF PERIOD:
MVFR/VFR CEILINGS RANGING FROM 1500-4500 FT AGL ARE EXPECTED ACROSS
CENTRAL NC THIS AFTERNOON...WITH THE BEST CHANCE OF MVFR CEILINGS AT
THE INT/GSO TERMINALS THROUGH EARLY/MID AFTERNOON...THEN EQUAL
CHANCES AT ALL TERMINALS MID AFTERNOON THROUGH MIDNIGHT IN ASSOC/W
SCATTERED SHOWERS AND THUNDERSTORMS. SUB-VFR CEILINGS OR FOG WILL BE
POSSIBLE ONCE AGAIN OVERNIGHT...PRIMARILY BETWEEN 06-14Z MONDAY
MORNING.

LOOKING AHEAD:
THE PROBABILITY FOR SHOWERS AND THUNDERSTORMS WILL FURTHER INCREASE
MON AFT/EVE INTO MON NIGHT AT ALL TERMINALS...IN ASSOCIATION WITH
STRENGTHENING CYCLONIC FLOW ALOFT AND A COLD FRONT APPROACHING THE
REGION FROM THE NORTHWEST. THE FRONT IS EXPECTED TO PROGRESS
SOUTHEAST ACROSS CENTRAL NC DURING THE DAY TUE...WITH THE BEST
CHANCE OF SHOWERS AND THUNDERSTORMS SHIFTING TO THE EASTERN
TERMINALS (RDU/FAY/RWI) BY TUE AFTERNOON. ASIDE FROM A CHANCE FOR
FOG NEAR AND JUST PRIOR TO SUNRISE (08-12Z) WED/THU...EXPECT VFR
CONDITIONS IN THE WAKE OF THE FRONT AS HIGH PRESSURE BUILDS INTO THE
REGION. -VINCENT

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...HARTFIELD
LONG TERM...ELLIS
AVIATION...VINCENT









AREA FORECAST DISCUSSION

NWS RALEIGH NC

 1234 PM EDT SUN SEP 01 2013

.SYNOPSIS...
A WARM AND MOIST SOUTHERLY FLOW WILL PERSIST THROUGH MONDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST MONDAY NIGHT...
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 1230 PM SUNDAY...

UPPER LEVEL DISTURBANCES WILL TRAVERSE THE REGION IN STRENGTHENING
CYCLONIC FLOW ALOFT THIS AFT/EVE...IN THE PRESENCE OF MODERATE
INSTABILITY (MLCAPE 1500-2000 J/KG) ASSOC/W STRONG INSOLATION AND A
VERY MOIST LOW-LEVEL AIRMASS. AS OF 16Z...ISOLATED TO SCATTERED
CONVECTION HAS DEVELOPED ALONG THE HIGHWAY 1 IN ASSOCIATION WITH
STRONG INSOLATION /RAPID EROSION OF CINH/ AND A SMALL AMPLITUDE
DISTURBANCE ALOFT PER WV IMAGERY AND RAP DATA. EXPECT THE BEST
CHANCE FOR CONVECTION THIS AFTERNOON EAST OF THE HIGHWAY 1 CORRIDOR
AS THE AFOREMENTIONED DISTURBANCE TRACKS SLOWLY EAST TOWARD THE
COAST...FOLLOWED BY INCREASING CHANCES IN THE WESTERN PIEDMONT BY
LATE THIS AFTERNOON THROUGH THIS EVENING AS A SMALL AMPLITUDE WAVE
(IN EASTERN KY AT 16Z) TRACKS SLOWLY EAST IN VICINITY OF THE
NORTHWEST NC AND SOUTHWEST VA BORDER. DESPITE MODERATE
INSTABILITY...GIVEN WEAK DEEP LAYER SHEAR (<= 20 KT)...WEAK TO
MARGINAL DCAPE (500-1000 J/KG) AND WEAK MID-LEVEL LAPSE RATES...FEEL
THAT THE POTENTIAL FOR AN ISOLD SVR STORM IS TOO LOW TO WARRANT
MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. A SLIGHT
CHANCE OF SHOWERS WILL LIKELY PERSIST OVERNIGHT GIVEN EXCELLENT DEEP
LAYER MOISTURE AND MARGINAL NOCTURNAL INSTABILITY IN THE PRESENCE OF
CYCLONIC FLOW ALOFT...WITH THE RELATIVE BEST CHANCE NEAR THE VA
BORDER WHERE DPVA APPEARS MORE LIKELY. EXPECT HIGHS IN THE UPPER 80S
TO LOWER 90S...OR 87-92F...HIGHEST IN THE COASTAL PLAIN. LOWS
TONIGHT IN THE LOWER TO MID 70S...OR 70-74F. -VINCENT

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...

SHOULD BE ANOTHER FAIRLY ACTIVE DAY. LONGWAVE TROUGHING WILL DIG
DOWN OVER ERN NOAM AS A SHORTWAVE TROUGH FROM SRN ONTARIO THROUGH MI
SWINGS ESE... YIELDING HEIGHT FALLS OF AROUND 20-30 M OVER NC
MON/MON NIGHT. THE COLD FRONT NOW STRETCHING FROM THE UPPER MIDWEST
LOW SSW THROUGH THE CENTRAL PLAINS WILL CONTINUE TO PUSH ESE...
THROUGH THE OH VALLEY MONDAY THEN TO THE APPALACHIANS BY MONDAY
NIGHT... AS THE PRECEDING PIEDMONT TROUGH SHARPENS. THE LOW-MID
LEVEL FLOW FROM THE SW AND WSW WILL ENSURE CONTINUED ABOVE-NORMAL
MOISTURE CONTENT THROUGH THE COLUMN WITH PW VALUES HOLDING AT
1.7-1.8 INCHES FROM THE TRIANGLE EAST/SE... ALTHOUGH THE MORE WNW
DOWNSLOPE FLOW OVER THE NW PIEDMONT IS EXPECTED TO CAUSE PW VALUES
TO DROP BELOW 1.5 IN. MODELS DIFFER CONSIDERABLY WITH THEIR
INSTABILITY... WITH THE NAM DEPICTING LOWER MLCAPE UNDER 2000 J/KG
FROM THE TRIANGLE SOUTH AND EAST WITH 2000-2500 J/KG OVER THE NW
CWA... WHILE THE GFS IS NEARLY OPPOSITE WITH MLCAPE LOW OVER THE NW
AND PEAKING AT 1500-2500 J/KG OVER THE SOUTH AND EAST MONDAY
AFTERNOON. THIS IS LARGELY A REFLECTION OF SURFACE DEW POINTS...
WHICH ARE DIFFICULT TO RESOLVE IN THE MODELS AT THIS RANGE. AS
SUCH... IT IS TOUGH TO DETERMINE THE THREAT OF STRONG STORMS...
ALTHOUGH THE DEEP LAYER BULK SHEAR REMAINS MARGINAL AT JUST 10-15
KTS... WHICH WILL LIMIT STORM ORGANIZATION AND STRENGTH. IN ANY
CASE... WE SHOULD STILL SEE AT LEAST SCATTERED STORMS DEVELOPING BY
AFTERNOON... MOST LIKELY STARTING OUT AS ISOLATED MOUNTAIN
CONVECTION DROPPING TO THE ESE AND CONGEALING INTO A BROKEN LINE OF
COLD POOL DOMINATED STORMS. GFS STATISTICAL GUIDANCE HIGHS APPEAR
TOO WARM GIVEN THAT WE SHOULD SEE QUITE A BIT OF CONVECTIVE DEBRIS
MID/HIGH CLOUDS... AND ITS JUMP IN AFTERNOON THICKNESS (BEYOND 1430
M) IS A VAST DEPARTURE FROM OTHER GUIDANCE. WILL RETAIN HIGHS NEAR
90 TO THE LOWER 90S. LOWS 69-73 WITH PARTLY CLOUDY SKIES AND A
LINGERING ISOLATED SHOWER/STORM CHANCE. -GIH

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...

THE LONG TERM PATTERN WILL FEATURES A PERSISTENT HIGH-AMPLITUDE
SOUTHERN ROCKY MOUNTAIN/WESTERN PLAINS RIDGE AND AN EASTERN U.S.
TROUGH THAT GRADUALLY DEAMPLIFIES AT THE END OF THE PERIOD. WHILE
THE MAIN TROUGH LIFTS NORTH LATE IN THE WORK WEEK...A MID-LEVEL
WEAKNESS AND TROUGH LINGERS WEST OF OUR REGION ON FRIDAY AND
SATURDAY.

THE UPPER LEVEL TROUGH AXIS SWINGS THROUGH CENTRAL NC ON TUESDAY AND
TUESDAY NIGHT. THE GFS IS THE FASTEST SET OF GUIDANCE WHILE THE NAM
IS THE SLOWEST WITH THE EC IN BETWEEN. THE TIMING OF THE UPPER LEVEL
TROUGH IS CONSISTENT WITH THE PASSAGE OF THE SURFACE COLD FRONT.
GIVEN THE MEAGER FLOW ALOFT AND THE WEAK SURFACE HIGH BEHIND THE
FRONT AS WELL AS GUIDANCE TRENDS WHICH SUGGEST A SLOWER FRONTAL
PASSAGE...PREFER TO USE THE SLOWER TIMING. MUCH DRIER AIR WILL BE
WORKING INTO THE WESTERN PIEDMONT BY EARLY TUESDAY AFTERNOON WHILE
THE DEEPEST MOISTURE AND INSTABILITY WILL BE LOCATED ACROSS THE
COASTAL PLAIN. HIGHS TUESDAY WILL RANGE IN THE UPPER 80S.. BUT WITH
A COOLER AIR MASS ARRIVING FROM THE WEST...LOWS TUESDAY NIGHT WILL
RANGE FROM THE LOWER 60S IN THE TRIAD TO THE UPPER 60S IN THE
SOUTHERN COASTAL PLAIN.

THE FRONT WILL CONTINUE TO PUSH SOUTH ON WEDNESDAY AND MUCH DRIER
AIR WILL WORK INTO THE REGION FROM THE NORTH. A MORNING SHOWER IS
STILL POSSIBLE IN THE SOUTHERN COASTAL PLAIN AND SANDHILLS AS THE
LOW LEVEL MOISTURE IN THAT AREA IS A BIT MORE STUBBORN. AFTERNOON
PRECIPITABLE WATER VALUES WILL RANGE FROM AROUND 0.75 INCHES NEAR
THE VA BORDER TO 1.5 INCHES TOWARD FAR SOUTHERN PORTIONS OF THE
COASTAL PLAIN. HIGHS WILL RANGE IN THE LOWER TO MID 80S AND LOWS
WEDNESDAY NIGHT WILL RANGE IN THE LOWER TO MID 60S.

FAIRLY QUIET WEATHER IS EXPECTED ON THURSDAY AND FRIDAY AS HIGH
PRESSURE LINGERS ACROSS THE OHIO VALLEY AND ANOTHER COLD FRONT
PUSHES SOUTH ACROSS THE NORTHEAST BUT STALLS IN THE MID-ATLANTIC.
THE NORTHEAST LOW LEVEL FLOW ON THURSDAY VEERS AROUND TO SOUTH AND
SOUTHEAST ON FRIDAY AND CONTINUES INTO SATURDAY. THE RESULT WILL BE
A GRADUAL INCREASE IN MOISTURE AND SOME ENHANCED UPSLOPE FLOW ACROSS
WESTERN NC. THIS PATTERN WILL LIKELY RESULT IN SOME ISOLATED
AFTERNOON AND EVENING CONVECTION...MAINLY DRIVEN BY LOCAL PROCESSES
SUCH AS DIFFERENTIAL HEATING IN THE MOUNTAINS AND ALONG THE SEA
BREEZE. OTHERWISE EXPECT PARTLY CLOUDY SKIES WITH SOME MORNING
FOG/STRATUS POSSIBLE ON FRIDAY AND SATURDAY MORNINGS. HIGHS DURING
THE PERIOD WILL GENERALLY RANGE IN THE LOWER TO MID 80S WITH MORNING
LOWS MAINLY IN THE LOWER TO MID 60S. -BLAES

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 1200 PM SUNDAY...

24-HR TAF PERIOD:
MVFR/VFR CEILINGS RANGING FROM 1500-4500 FT AGL ARE EXPECTED ACROSS
CENTRAL NC THIS AFTERNOON...WITH THE BEST CHANCE OF MVFR CEILINGS AT
THE INT/GSO TERMINALS THROUGH EARLY/MID AFTERNOON...THEN EQUAL
CHANCES AT ALL TERMINALS MID AFTERNOON THROUGH MIDNIGHT IN ASSOC/W
SCATTERED SHOWERS AND THUNDERSTORMS. SUB-VFR CEILINGS OR FOG WILL BE
POSSIBLE ONCE AGAIN OVERNIGHT...PRIMARILY BETWEEN 06-14Z MONDAY
MORNING.

LOOKING AHEAD:
THE PROBABILITY FOR SHOWERS AND THUNDERSTORMS WILL FURTHER INCREASE
MON AFT/EVE INTO MON NIGHT AT ALL TERMINALS...IN ASSOCIATION WITH
STRENGTHENING CYCLONIC FLOW ALOFT AND A COLD FRONT APPROACHING THE
REGION FROM THE NORTHWEST. THE FRONT IS EXPECTED TO PROGRESS
SOUTHEAST ACROSS CENTRAL NC DURING THE DAY TUE...WITH THE BEST
CHANCE OF SHOWERS AND THUNDERSTORMS SHIFTING TO THE EASTERN
TERMINALS (RDU/FAY/RWI) BY TUE AFTERNOON. ASIDE FROM A CHANCE FOR
FOG NEAR AND JUST PRIOR TO SUNRISE (08-12Z) WED/THU...EXPECT VFR
CONDITIONS IN THE WAKE OF THE FRONT AS HIGH PRESSURE BUILDS INTO THE
REGION. -VINCENT

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...HARTFIELD
LONG TERM...BLAES
AVIATION...VINCENT






AREA FORECAST DISCUSSION

NWS RALEIGH NC

 302 AM EDT SUN SEP 01 2013

.SYNOPSIS...
A WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE THROUGH MONDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST MONDAY NIGHT...
THEN PUSH SLOWLY SOUTHEAST THROUGH THE CAROLINAS TUESDAY AND TUESDAY
NIGHT. BEHIND THE FRONT... HIGH PRESSURE WILL BUILD INTO THE REGION
FROM THE NORTHWEST WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /TODAY AND TONIGHT/...
AS OF 220 AM SUNDAY...

WE`RE STILL EXPECTING SCATTERED SHOWERS/STORMS TODAY INTO THIS
EVENING... ALTHOUGH DETAILS AS TO WHO WILL SEE THE BEST CHANCES AND
WHEN REMAIN MURKY. LATEST SURFACE MAP SHOWS THE SYNOPTIC FRONTAL
ZONE EXTENDING FROM A LOW OVER THE UPPER MIDWEST ACROSS THE LOWER
GREAT LAKES AND ST LAWRENCE VALLEY... WHILE WEAK LEE SURFACE
TROUGHING HOLDS OVER CENTRAL VA/NC. TWO PRIMARY FORCING FEATURES ARE
EXPECTED TO DRIVE OUR PRECIP CHANCES TODAY. FIRST IS A MID LEVEL
SHORTWAVE -- A REFLECTION OF YESTERDAY`S CONVECTION TO THE WEST OVER
THE MOUNTAINS -- NOW TRACKING THROUGH MD/VA/NC AND EXPECTED TO SHIFT
SLOWLY ESE THEN EAST INTO ERN VA/NC THIS MORNING. THIS SHOULD
ENCOUNTER A MOIST (AND INCREASINGLY SO... WITH PW VALUES EXPECTED TO
QUICKLY JUMP UP TOWARD 1.8-1.9 IN.) ENVIRONMENT OVER THE COASTAL
PLAIN AND COASTAL AREA. WITH DEW POINTS IN THE 70-75 RANGE AND GOOD
MORNING HEATING ALLOWING THE CONVECTIVE TEMP TO BE REACHED BY
MID-LATE MORNING... EXPECT EARLY DEVELOPMENT OF SHOWERS/STORMS OVER
THE COASTAL PLAIN AND SANDHILLS... AUGMENTED BY AN INLAND-MOVING SEA
BREEZE BY AFTERNOON. THE SECOND FEATURE OF INTEREST IS AN MCV
RESULTING FROM THE ORGANIZED STORMS NOW OVER SRN IN/IL EXTENDING
THROUGH THE OH VALLEY. THIS WAVE SHOULD FOLLOW IN THE TRACKS OF THE
PREVIOUS ONE... SHIFTING ESE THEN EAST DURING THE DAY... POTENTIALLY
ENHANCING CONVECTION OVER THE CENTRAL/SRN APPALACHIANS WHICH WOULD
THEN DRIFT EASTWARD OFF THE HIGHER TERRAIN INTO THE FOOTHILLS AND
WRN PIEDMONT LATER IN THE DAY INTO EARLY EVENING. THE NAM/GFS
GENERALLY FIT WITH THE SCENARIO OUTLINED HERE FOR THE TWO
FEATURES... SO WHILE THE OVERALL FORECAST WILL REFLECT SCATTERED
STORMS (30-50% POPS) OVER ALL OF CENTRAL NC... THE FORECAST TIMING
WILL SHOW GREATER POPS SOUTHEAST OF RALEIGH STARTING IN THE LATE
MORNING... THEN PEAKING LATER (MID AFTERNOON) OVER THE WRN
PIEDMONT... SHIFTING EAST INTO THE ERN PIEDMONT AND WRN SANDHILLS
BEFORE DISSIPATING BY MID TO LATE EVENING WITH LOSS OF HEATING AND
WEAK POST-WAVE SUBSIDENCE. REGARDING STORM STRENGTH... MLCAPE IS
EXPECTED TO TOP OUT AT 1500-2000 J/KG MAINLY OVER THE ERN CWA... BUT
DEEP LAYER SHEAR REMAINS WEAK AT AROUND 15 KTS. WE MAY SEE A FEW
STRONG GUSTS WITH ISOLATED CELLS BASED ON THE FORECAST SOUNDING
PROFILES... BUT WIDESPREAD STRONG/SEVERE STORMS ARE NOT EXPECTED.
TEMPS ARE TOUGH AS ABOVE-NORMAL THICKNESSES (BY ABOUT 10-12 M) WILL
BE MODULATED BY SOME MORNING STRATUS AND CONVECTIVE CLOUD COVER THIS
AFTERNOON. GRIDDED LAMP GUIDANCE INDICATES HIGHS OF 88-92... CLOSE
TO THAT INDICATED BY A DRY ADIABATIC LAPSE RATE... AND ABOUT A
DEGREE ABOVE EARLIER FORECAST HIGHS. EXPECT GENERALLY PARTLY CLOUDY
SKIES TONIGHT WITH VARYING DEGREES OF CONVECTIVE DEBRIS CLOUDINESS
OVER THE REGION. LOWS 69-73. -GIH

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SUNDAY...

SHOULD BE ANOTHER FAIRLY ACTIVE DAY. LONGWAVE TROUGHING WILL DIG
DOWN OVER ERN NOAM AS A SHORTWAVE TROUGH FROM SRN ONTARIO THROUGH MI
SWINGS ESE... YIELDING HEIGHT FALLS OF AROUND 20-30 M OVER NC
MON/MON NIGHT. THE COLD FRONT NOW STRETCHING FROM THE UPPER MIDWEST
LOW SSW THROUGH THE CENTRAL PLAINS WILL CONTINUE TO PUSH ESE...
THROUGH THE OH VALLEY MONDAY THEN TO THE APPALACHIANS BY MONDAY
NIGHT... AS THE PRECEDING PIEDMONT TROUGH SHARPENS. THE LOW-MID
LEVEL FLOW FROM THE SW AND WSW WILL ENSURE CONTINUED ABOVE-NORMAL
MOISTURE CONTENT THROUGH THE COLUMN WITH PW VALUES HOLDING AT
1.7-1.8 INCHES FROM THE TRIANGLE EAST/SE... ALTHOUGH THE MORE WNW
DOWNSLOPE FLOW OVER THE NW PIEDMONT IS EXPECTED TO CAUSE PW VALUES
TO DROP BELOW 1.5 IN. MODELS DIFFER CONSIDERABLY WITH THEIR
INSTABILITY... WITH THE NAM DEPICTING LOWER MLCAPE UNDER 2000 J/KG
FROM THE TRIANGLE SOUTH AND EAST WITH 2000-2500 J/KG OVER THE NW
CWA... WHILE THE GFS IS NEARLY OPPOSITE WITH MLCAPE LOW OVER THE NW
AND PEAKING AT 1500-2500 J/KG OVER THE SOUTH AND EAST MONDAY
AFTERNOON. THIS IS LARGELY A REFLECTION OF SURFACE DEW POINTS...
WHICH ARE DIFFICULT TO RESOLVE IN THE MODELS AT THIS RANGE. AS
SUCH... IT IS TOUGH TO DETERMINE THE THREAT OF STRONG STORMS...
ALTHOUGH THE DEEP LAYER BULK SHEAR REMAINS MARGINAL AT JUST 10-15
KTS... WHICH WILL LIMIT STORM ORGANIZATION AND STRENGTH. IN ANY
CASE... WE SHOULD STILL SEE AT LEAST SCATTERED STORMS DEVELOPING BY
AFTERNOON... MOST LIKELY STARTING OUT AS ISOLATED MOUNTAIN
CONVECTIONS DROPPING TO THE ESE AND CONGEALING INTO A BROKEN LINE OF
COLD POOL DOMINATED STORMS. GFS STATISTICAL GUIDANCE HIGHS APPEAR
TOO WARM GIVEN THAT WE SHOULD SEE QUITE A BIT OF CONVECTIVE DEBRIS
MID/HIGH CLOUDS... AND ITS JUMP IN AFTERNOON THICKNESS (BEYOND 1430
M) IS A VAST DEPARTURE FROM OTHER GUIDANCE. WILL RETAIN HIGHS NEAR
90 TO THE LOWER 90S. LOWS 69-73 WITH PARTLY CLOUDY SKIES AND A
LINGERING ISOLATED SHOWER/STORM CHANCE. -GIH

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...

THE LONG TERM PATTERN WILL FEATURES A PERSISTENT HIGH-AMPLITUDE
SOUTHERN ROCKY MOUNTAIN/WESTERN PLAINS RIDGE AND AN EASTERN U.S.
TROUGH THAT GRADUALLY DEAMPLIFIES AT THE END OF THE PERIOD. WHILE
THE MAIN TROUGH LIFTS NORTH LATE IN THE WORK WEEK...A MID-LEVEL
WEAKNESS AND TROUGH LINGERS WEST OF OUR REGION ON FRIDAY AND
SATURDAY.

THE UPPER LEVEL TROUGH AXIS SWINGS THROUGH CENTRAL NC ON TUESDAY AND
TUESDAY NIGHT. THE GFS IS THE FASTEST SET OF GUIDANCE WHILE THE NAM
IS THE SLOWEST WITH THE EC IN BETWEEN. THE TIMING OF THE UPPER LEVEL
TROUGH IS CONSISTENT WITH THE PASSAGE OF THE SURFACE COLD FRONT.
GIVEN THE MEAGER FLOW ALOFT AND THE WEAK SURFACE HIGH BEHIND THE
FRONT AS WELL AS GUIDANCE TRENDS WHICH SUGGEST A SLOWER FRONTAL
PASSAGE...PREFER TO USE THE SLOWER TIMING. MUCH DRIER AIR WILL BE
WORKING INTO THE WESTERN PIEDMONT BY EARLY TUESDAY AFTERNOON WHILE
THE DEEPEST MOISTURE AND INSTABILITY WILL BE LOCATED ACROSS THE
COASTAL PLAIN. HIGHS TUESDAY WILL RANGE IN THE UPPER 80S.. BUT WITH
A COOLER AIR MASS ARRIVING FROM THE WEST...LOWS TUESDAY NIGHT WILL
RANGE FROM THE LOWER 60S IN THE TRIAD TO THE UPPER 60S IN THE
SOUTHERN COASTAL PLAIN.

THE FRONT WILL CONTINUE TO PUSH SOUTH ON WEDNESDAY AND MUCH DRIER
AIR WILL WORK INTO THE REGION FROM THE NORTH. A MORNING SHOWER IS
STILL POSSIBLE IN THE SOUTHERN COASTAL PLAIN AND SANDHILLS AS THE
LOW LEVEL MOISTURE IN THAT AREA IS A BIT MORE STUBBORN. AFTERNOON
PRECIPITABLE WATER VALUES WILL RANGE FROM AROUND 0.75 INCHES NEAR
THE VA BORDER TO 1.5 INCHES TOWARD FAR SOUTHERN PORTIONS OF THE
COASTAL PLAIN. HIGHS WILL RANGE IN THE LOWER TO MID 80S AND LOWS
WEDNESDAY NIGHT WILL RANGE IN THE LOWER TO MID 60S.

FAIRLY QUIET WEATHER IS EXPECTED ON THURSDAY AND FRIDAY AS HIGH
PRESSURE LINGERS ACROSS THE OHIO VALLEY AND ANOTHER COLD FRONT
PUSHES SOUTH ACROSS THE NORTHEAST BUT STALLS IN THE MID-ATLANTIC.
THE NORTHEAST LOW LEVEL FLOW ON THURSDAY VEERS AROUND TO SOUTH AND
SOUTHEAST ON FRIDAY AND CONTINUES INTO SATURDAY. THE RESULT WILL BE
A GRADUAL INCREASE IN MOISTURE AND SOME ENHANCED UPSLOPE FLOW ACROSS
WESTERN NC. THIS PATTERN WILL LIKELY RESULT IN SOME ISOLATED
AFTERNOON AND EVENING CONVECTION...MAINLY DRIVEN BY LOCAL PROCESSES
SUCH AS DIFFERENTIAL HEATING IN THE MOUNTAINS AND ALONG THE SEA
BREEZE. OTHERWISE EXPECT PARTLY CLOUDY SKIES WITH SOME MORNING
FOG/STRATUS POSSIBLE ON FRIDAY AND SATURDAY MORNINGS. HIGHS DURING
THE PERIOD WILL GENERALLY RANGE IN THE LOWER TO MID 80S WITH MORNING
LOWS MAINLY IN THE LOWER TO MID 60S. -BLAES



&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...

CURRENT VFR CONDITIONS ARE EXPECTED TO YIELD TO IFR CONDITIONS LATE
TONIGHT... BUT CONFIDENCE IN THE TIMING AND EXTENT OF LOW CIGS/VSBYS
IS LOWER THAN USUAL. THE SURFACE MAP SHOWS THE LARGE SCALE COLD
FRONT STILL WELL TO OUR NORTH (EAST-WEST ACROSS THE LOWER GREAT
LAKES) WITH A WEAK LEE TROUGH EAST OF THE APPALACHIANS EXTENDING
THROUGH CENTRAL NC... AND THIS SETUP SHOULD CHANGE LITTLE THROUGH
THE NEXT 24 HOURS. A WARM/MOIST LOW LEVEL FLOW FROM THE SW CONTINUES
TO PUMP INCREASING LOW LEVEL MOISTURE INTO THE AREA... AND THIS WILL
LIKELY LEAD TO FORMATION OF IFR STRATUS AND MVFR FOG AS THE LOW
LEVELS STABILIZE FURTHER AND DECOUPLE. THE RESIDUAL CLOUDS FROM
EARLIER STORMS OVER THE MOUNTAINS/FOOTHILLS HAVE MOVED EAST OF THE
TRIAD AND INTO THE ERN AND SRN PIEDMONT... AND THE BRIEF CLEARING
SKIES AND MOIST GROUND AT INT/GSO (THE ONLY CENTRAL NC TAF SITES
THAT SAW RAIN TODAY) SHOULD FACILITATE DEVELOPMENT OF LOW CLOUDS AND
FOG. THIS IS SUPPORTED BY RECENT RUNS OF THE HRRR MODEL INDICATING
POSSIBLE VSBYS UNDER A HALF MILE AT INT/GSO. FARTHER EAST... THE
RESIDUAL CLOUDS DRIFTING EASTWARD SHOULD LIMIT FOG FORMATION AND
DELAY (IF NOT LIMIT) LOW CLOUD DEVELOPMENT... HOWEVER THE NAM/GFS
STATISTICAL GUIDANCE SUGGESTS THAT ALMOST THE OPPOSITE WILL OCCUR --
SHOWING CIGS DROPPING TO UNDER 1000 FT LATE TONIGHT AT THE EASTERN
TAF SITES OF RDU/RWI/FAY OVERNIGHT. WILL INDICATE A TREND TO
PREVAILING IFR CIGS/VSBYS AT INT/GSO THROUGH DAYBREAK... WITH JUST
TEMPORARY IFR CONDITIONS AT RDU/FAY/RWI FOR NOW UNTIL THE PICTURE
BECOMES CLEARER. EXPECT VFR CONDITIONS TO RESUME AT ALL SITES WITH
DAYTIME HEATING AFTER 14Z. SCATTERED SHOWERS/STORMS EXPECTED FROM
LATE MORNING THROUGH THE AFTERNOON HOURS MAY PRODUCE LOCALLY HEAVY
DOWNPOURS AND GUSTY WINDS WITH BRIEF IFR/LIFR CONDITIONS AT ANY
SITE. OTHERWISE... VFR CONDITIONS SHOULD DOMINATE THROUGH THE END OF
THE TAF VALID PERIOD (06Z EARLY MONDAY MORNING).

LOOKING BEYOND 06Z EARLY MONDAY MORNING... SHALLOW IFR FOG IS
POSSIBLE 08Z-12Z AT ALL FIVE TAF SITES AS WE MAINTAIN A LIGHT SW
SURFACE FLOW. ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND
STORMS ARE EXPECTED ACROSS CENTRAL NC BOTH MONDAY AND TUESDAY
AFTERNOON/EVENING... AHEAD OF A COLD FRONT APPROACHING SLOWLY FROM
THE NW... AND ANY OF THESE SHOWERS/STORMS COULD GENERATE GUSTY WINDS
AND SUB-VFR CONDITIONS WITH BRIEF HEAVY RAIN. VFR CONDITIONS ARE
LIKELY TO RETURN FOR WEDNESDAY/THURSDAY AS HIGH PRESSURE BUILDS IN
FROM THE NW WITH MUCH DRIER AIR. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...HARTFIELD
LONG TERM...BLAES
AVIATION...HARTFIELD







AREA FORECAST DISCUSSION

NWS RALEIGH NC

 224 AM EDT SUN SEP 01 2013

.SYNOPSIS...
A WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE THROUGH MONDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST MONDAY
NIGHT...THEN PUSH SLOWLY SOUTHEAST THROUGH THE CAROLINAS TUESDAY AND
TUESDAY NIGHT. BEHIND THE FRONT... HIGH PRESSURE WILL BUILD INTO THE
REGION FROM THE NORTHWEST WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /TODAY AND TONIGHT/...
AS OF 220 AM SUNDAY...

WE`RE STILL EXPECTING SCATTERED SHOWERS/STORMS TODAY INTO THIS
EVENING... ALTHOUGH DETAILS AS TO WHO WILL SEE THE BEST CHANCES AND
WHEN REMAIN MURKY. LATEST SURFACE MAP SHOWS THE SYNOPTIC FRONTAL
ZONE EXTENDING FROM A LOW OVER THE UPPER MIDWEST ACROSS THE LOWER
GREAT LAKES AND ST LAWRENCE VALLEY... WHILE WEAK LEE SURFACE
TROUGHING HOLDS OVER CENTRAL VA/NC. TWO PRIMARY FORCING FEATURES ARE
EXPECTED TO DRIVE OUR PRECIP CHANCES TODAY. FIRST IS A MID LEVEL
SHORTWAVE -- A REFLECTION OF YESTERDAY`S CONVECTION TO THE WEST OVER
THE MOUNTAINS -- NOW TRACKING THROUGH MD/VA/NC AND EXPECTED TO SHIFT
SLOWLY ESE THEN EAST INTO ERN VA/NC THIS MORNING. THIS SHOULD
ENCOUNTER A MOIST (AND INCREASINGLY SO... WITH PW VALUES EXPECTED TO
QUICKLY JUMP UP TOWARD 1.8-1.9 IN.) ENVIRONMENT OVER THE COASTAL
PLAIN AND COASTAL AREA. WITH DEW POINTS IN THE 70-75 RANGE AND GOOD
MORNING HEATING ALLOWING THE CONVECTIVE TEMP TO BE REACHED BY
MID-LATE MORNING... EXPECT EARLY DEVELOPMENT OF SHOWERS/STORMS OVER
THE COASTAL PLAIN AND SANDHILLS... AUGMENTED BY AN INLAND-MOVING SEA
BREEZE BY AFTERNOON. THE SECOND FEATURE OF INTEREST IS AN MCV
RESULTING FROM THE ORGANIZED STORMS NOW OVER SRN IN/IL EXTENDING
THROUGH THE OH VALLEY. THIS WAVE SHOULD FOLLOW IN THE TRACKS OF THE
PREVIOUS ONE... SHIFTING ESE THEN EAST DURING THE DAY... POTENTIALLY
ENHANCING CONVECTION OVER THE CENTRAL/SRN APPALACHIANS WHICH WOULD
THEN DRIFT EASTWARD OFF THE HIGHER TERRAIN INTO THE FOOTHILLS AND
WRN PIEDMONT LATER IN THE DAY INTO EARLY EVENING. THE NAM/GFS
GENERALLY FIT WITH THE SCENARIO OUTLINED HERE FOR THE TWO
FEATURES... SO WHILE THE OVERALL FORECAST WILL REFLECT SCATTERED
STORMS (30-50% POPS) OVER ALL OF CENTRAL NC... THE FORECAST TIMING
WILL SHOW GREATER POPS SOUTHEAST OF RALEIGH STARTING IN THE LATE
MORNING... THEN PEAKING LATER (MID AFTERNOON) OVER THE WRN
PIEDMONT... SHIFTING EAST INTO THE ERN PIEDMONT AND WRN SANDHILLS
BEFORE DISSIPATING BY MID TO LATE EVENING WITH LOSS OF HEATING AND
WEAK POST-WAVE SUBSIDENCE. REGARDING STORM STRENGTH... MLCAPE IS
EXPECTED TO TOP OUT AT 1500-2000 J/KG MAINLY OVER THE ERN CWA... BUT
DEEP LAYER SHEAR REMAINS WEAK AT AROUND 15 KTS. WE MAY SEE A FEW
STRONG GUSTS WITH ISOLATED CELLS BASED ON THE FORECAST SOUNDING
PROFILES... BUT WIDESPREAD STRONG/SEVERE STORMS ARE NOT EXPECTED.
TEMPS ARE TOUGH AS ABOVE-NORMAL THICKNESSES (BY ABOUT 10-12 M) WILL
BE MODULATED BY SOME MORNING STRATUS AND CONVECTIVE CLOUD COVER THIS
AFTERNOON. GRIDDED LAMP GUIDANCE INDICATES HIGHS OF 88-92... CLOSE
TO THAT INDICATED BY A DRY ADIABATIC LAPSE RATE... AND ABOUT A
DEGREE ABOVE EARLIER FORECAST HIGHS. EXPECT GENERALLY PARTLY CLOUDY
SKIES TONIGHT WITH VARYING DEGREES OF CONVECTIVE DEBRIS CLOUDINESS
OVER THE REGION. LOWS 69-73. -GIH

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 215 PM SATURDAY...

MONDAY WILL BEGIN WITH TWO FRONTAL SYSTEMS...ONE ON EITHER SIDE OF
THE CWA WITH THE LEAD FRONT OFF THE COAST AND THE TRAILING FRONT
BACK ACROSS THE OHIO AND LOWER MISSISSIPPI VALLEYS. MODEL FORECAST
SOUNDINGS VIEWED IN BUFKIT SHOW AN ELEVATED MIXED LAYER PRESENT FROM
ROUGHLY 800 MB UP TO 600 MB WHICH GREATLY INCREASES INSTABILITY...ON
THE ORDER OF 1500-2000 J/KG. MID-LEVEL LAPSE RATES OF 6-7 DEGREES
PER KM AND PRECIPITABLE WATER VALUES OF AROUND 1.75 INCHES ALL
INDICATE THE POTENTIAL FOR CONVECTION. HAIL AND WINDS COULD BOTH BE
A POSSIBILITY AS THE HAIL GROWTH ZONE BECOMES FAIRLY SATURATED BY
AFTERNOON. IN ADDITION DCAPE VALUES BETWEEN KRDU AND KGSO SHOULD BE
BETWEEN 1000 AND 1500 J/KG. DESPITE THIS...SHEAR WILL BE
MINIMAL...WITH BULK VALUES 15-20 KNOTS AT BEST. WHILE WIDESPREAD
CONVECTION IS NOT LIKELY...THE WILL BE A CHANCE OF SCATTERED STORMS
WITH A FEW OF THEM POTENTIALLY BECOMING SEVERE. HIGHS IN THE LOW
90S...LOWS UPPER 70S. -MLM
&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...

THE LONG TERM PATTERN WILL FEATURES A PERSISTENT HIGH-AMPLITUDE
SOUTHERN ROCKY MOUNTAIN/WESTERN PLAINS RIDGE AND AN EASTERN U.S.
TROUGH THAT GRADUALLY DEAMPLIFIES AT THE END OF THE PERIOD. WHILE
THE MAIN TROUGH LIFTS NORTH LATE IN THE WORK WEEK...A MID-LEVEL
WEAKNESS AND TROUGH LINGERS WEST OF OUR REGION ON FRIDAY AND
SATURDAY.

THE UPPER LEVEL TROUGH AXIS SWINGS THROUGH CENTRAL NC ON TUESDAY AND
TUESDAY NIGHT. THE GFS IS THE FASTEST SET OF GUIDANCE WHILE THE NAM
IS THE SLOWEST WITH THE EC IN BETWEEN. THE TIMING OF THE UPPER LEVEL
TROUGH IS CONSISTENT WITH THE PASSAGE OF THE SURFACE COLD FRONT.
GIVEN THE MEAGER FLOW ALOFT AND THE WEAK SURFACE HIGH BEHIND THE
FRONT AS WELL AS GUIDANCE TRENDS WHICH SUGGEST A SLOWER FRONTAL
PASSAGE...PREFER TO USE THE SLOWER TIMING. MUCH DRIER AIR WILL BE
WORKING INTO THE WESTERN PIEDMONT BY EARLY TUESDAY AFTERNOON WHILE
THE DEEPEST MOISTURE AND INSTABILITY WILL BE LOCATED ACROSS THE
COASTAL PLAIN. HIGHS TUESDAY WILL RANGE IN THE UPPER 80S.. BUT WITH
A COOLER AIR MASS ARRIVING FROM THE WEST...LOWS TUESDAY NIGHT WILL
RANGE FROM THE LOWER 60S IN THE TRIAD TO THE UPPER 60S IN THE
SOUTHERN COASTAL PLAIN.

THE FRONT WILL CONTINUE TO PUSH SOUTH ON WEDNESDAY AND MUCH DRIER
AIR WILL WORK INTO THE REGION FROM THE NORTH. A MORNING SHOWER IS
STILL POSSIBLE IN THE SOUTHERN COASTAL PLAIN AND SANDHILLS AS THE
LOW LEVEL MOISTURE IN THAT AREA IS A BIT MORE STUBBORN. AFTERNOON
PRECIPITABLE WATER VALUES WILL RANGE FROM AROUND 0.75 INCHES NEAR
THE VA BORDER TO 1.5 INCHES TOWARD FAR SOUTHERN PORTIONS OF THE
COASTAL PLAIN. HIGHS WILL RANGE IN THE LOWER TO MID 80S AND LOWS
WEDNESDAY NIGHT WILL RANGE IN THE LOWER TO MID 60S.

FAIRLY QUIET WEATHER IS EXPECTED ON THURSDAY AND FRIDAY AS HIGH
PRESSURE LINGERS ACROSS THE OHIO VALLEY AND ANOTHER COLD FRONT
PUSHES SOUTH ACROSS THE NORTHEAST BUT STALLS IN THE MID-ATLANTIC.
THE NORTHEAST LOW LEVEL FLOW ON THURSDAY VEERS AROUND TO SOUTH AND
SOUTHEAST ON FRIDAY AND CONTINUES INTO SATURDAY. THE RESULT WILL BE
A GRADUAL INCREASE IN MOISTURE AND SOME ENHANCED UPSLOPE FLOW ACROSS
WESTERN NC. THIS PATTERN WILL LIKELY RESULT IN SOME ISOLATED
AFTERNOON AND EVENING CONVECTION...MAINLY DRIVEN BY LOCAL PROCESSES
SUCH AS DIFFERENTIAL HEATING IN THE MOUNTAINS AND ALONG THE SEA
BREEZE. OTHERWISE EXPECT PARTLY CLOUDY SKIES WITH SOME MORNING
FOG/STRATUS POSSIBLE ON FRIDAY AND SATURDAY MORNINGS. HIGHS DURING
THE PERIOD WILL GENERALLY RANGE IN THE LOWER TO MID 80S WITH MORNING
LOWS MAINLY IN THE LOWER TO MID 60S. -BLAES



&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...

CURRENT VFR CONDITIONS ARE EXPECTED TO YIELD TO IFR CONDITIONS LATE
TONIGHT... BUT CONFIDENCE IN THE TIMING AND EXTENT OF LOW CIGS/VSBYS
IS LOWER THAN USUAL. THE SURFACE MAP SHOWS THE LARGE SCALE COLD
FRONT STILL WELL TO OUR NORTH (EAST-WEST ACROSS THE LOWER GREAT
LAKES) WITH A WEAK LEE TROUGH EAST OF THE APPALACHIANS EXTENDING
THROUGH CENTRAL NC... AND THIS SETUP SHOULD CHANGE LITTLE THROUGH
THE NEXT 24 HOURS. A WARM/MOIST LOW LEVEL FLOW FROM THE SW CONTINUES
TO PUMP INCREASING LOW LEVEL MOISTURE INTO THE AREA... AND THIS WILL
LIKELY LEAD TO FORMATION OF IFR STRATUS AND MVFR FOG AS THE LOW
LEVELS STABILIZE FURTHER AND DECOUPLE. THE RESIDUAL CLOUDS FROM
EARLIER STORMS OVER THE MOUNTAINS/FOOTHILLS HAVE MOVED EAST OF THE
TRIAD AND INTO THE ERN AND SRN PIEDMONT... AND THE BRIEF CLEARING
SKIES AND MOIST GROUND AT INT/GSO (THE ONLY CENTRAL NC TAF SITES
THAT SAW RAIN TODAY) SHOULD FACILITATE DEVELOPMENT OF LOW CLOUDS AND
FOG. THIS IS SUPPORTED BY RECENT RUNS OF THE HRRR MODEL INDICATING
POSSIBLE VSBYS UNDER A HALF MILE AT INT/GSO. FARTHER EAST... THE
RESIDUAL CLOUDS DRIFTING EASTWARD SHOULD LIMIT FOG FORMATION AND
DELAY (IF NOT LIMIT) LOW CLOUD DEVELOPMENT... HOWEVER THE NAM/GFS
STATISTICAL GUIDANCE SUGGESTS THAT ALMOST THE OPPOSITE WILL OCCUR --
SHOWING CIGS DROPPING TO UNDER 1000 FT LATE TONIGHT AT THE EASTERN
TAF SITES OF RDU/RWI/FAY OVERNIGHT. WILL INDICATE A TREND TO
PREVAILING IFR CIGS/VSBYS AT INT/GSO THROUGH DAYBREAK... WITH JUST
TEMPORARY IFR CONDITIONS AT RDU/FAY/RWI FOR NOW UNTIL THE PICTURE
BECOMES CLEARER. EXPECT VFR CONDITIONS TO RESUME AT ALL SITES WITH
DAYTIME HEATING AFTER 14Z. SCATTERED SHOWERS/STORMS EXPECTED FROM
LATE MORNING THROUGH THE AFTERNOON HOURS MAY PRODUCE LOCALLY HEAVY
DOWNPOURS AND GUSTY WINDS WITH BRIEF IFR/LIFR CONDITIONS AT ANY
SITE. OTHERWISE... VFR CONDITIONS SHOULD DOMINATE THROUGH THE END OF
THE TAF VALID PERIOD (06Z EARLY MONDAY MORNING).

LOOKING BEYOND 06Z EARLY MONDAY MORNING... SHALLOW IFR FOG IS
POSSIBLE 08Z-12Z AT ALL FIVE TAF SITES AS WE MAINTAIN A LIGHT SW
SURFACE FLOW. ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND
STORMS ARE EXPECTED ACROSS CENTRAL NC BOTH MONDAY AND TUESDAY
AFTERNOON/EVENING... AHEAD OF A COLD FRONT APPROACHING SLOWLY FROM
THE NW... AND ANY OF THESE SHOWERS/STORMS COULD GENERATE GUSTY WINDS
AND SUB-VFR CONDITIONS WITH BRIEF HEAVY RAIN. VFR CONDITIONS ARE
LIKELY TO RETURN FOR WEDNESDAY/THURSDAY AS HIGH PRESSURE BUILDS IN
FROM THE NW WITH MUCH DRIER AIR. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...MLM
LONG TERM...BLAES
AVIATION...HARTFIELD








AREA FORECAST DISCUSSION

NWS RALEIGH NC

 215 AM EDT SUN SEP 01 2013

.SYNOPSIS...
A WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE THROUGH MONDAY. A COLD
FRONT WILL APPROACH THE REGION FROM THE NORTHWEST MONDAY
NIGHT...THEN PUSH SLOWLY SOUTHEAST THROUGH THE CAROLINAS TUESDAY AND
TUESDAY NIGHT. BEHIND THE FRONT... HIGH PRESSURE WILL BUILD INTO THE
REGION FROM THE NORTHWEST WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /OVERNIGHT/...
AS OF 1025 PM SATURDAY...

BAND OF SHOWERS AND THUNDERSTORMS WHICH ENTERED THE NW PIEDMONT
AROUND 21Z DIMINISHED AS IT DRIFTED EAST. AIR MASS OVER BULK OF THE
PIEDMONT NOT AS UNSTABLE AS THE FOOTHILLS AND WESTERN PIEDMONT PLUS
LACK OF DECENT SHEAR AND LACK OF UPPER LEVEL SUPPORT LED TO THE
DISSIPATION OF MOST OF THE SHOWERS.

ANOTHER UPPER LEVEL DISTURBANCE IS APPROACHING WESTERN NC FROM THE
EASTERN TN VALLEY. THIS FEATURE PROJECTED TO CROSS OUR REGION
OVERNIGHT (AFTER 06Z). WITH PRECIP WATER VALUES 1.8-2 INCHES AND A
FEW SFC TROUGHS/OUTFLOW BOUNDARIES EXISTING ACROSS THE
REGION...COULD SEE A REGENERATION IN SHOWER/ISOLATED THUNDERSTORM
ACTIVITY OVERNIGHT-EARLY SUNDAY MORNING. PLAN TO MAINTAIN A SMALL
CHANCE POP ACROSS THE FAR NW-NORTHERN PIEDMONT...AND SLIGHT CHANCE
ACROSS MOST OF THE REMAINDER OF CENTRAL NC. OVERNIGHT MIN TEMPS
SHOULD BE FAIRLY UNIFORM AROUND 70.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 215 PM SATURDAY...

CYCLONIC FLOW ALOFT WILL STRENGTHEN ACROSS THE EASTERN CONUS AS
POTENT SHORTWAVE ENERGY TRACKING FROM SOUTHERN CANADA INTO THE UPPER
MIDWEST THIS AFTERNOON DIGS SOUTHEAST INTO THE UPPER GREAT LAKES ON
SUNDAY. AS A RESULT...A MOIST SOUTHWESTERLY LOW-LEVEL FLOW WILL
STRENGTHEN OVER THE CAROLINAS ON SUNDAY...WITH PWAT VALUES
INCREASING TO ABOVE NORMAL IN THE 1.75-2.00" RANGE AND DIURNAL
DESTABILIZATION YIELDING MARGINAL TO MODERATE INSTABILITY (1000-2000
J/KG MLCAPE) DURING PEAK HEATING. LOW-LEVEL FORCING ON SUNDAY WILL
BE ANEMIC ONCE AGAIN WITH LARGELY UNIDIRECTIONAL LOW-LEVEL FLOW...
THOUGH WITH STRONGER CYCLONIC FLOW ALOFT AND DEEPER MOISTURE ONE
WOULD EXPECT PRECIP CHANCES HIGHER THAN TODAY. ULTIMATELY...PRECIP
CHANCES WILL LIKELY DEPEND ON UPSTREAM DEVELOPMENT ACROSS THE HIGHER
TERRAIN IN WESTERN NC AND/OR THE TIMING OF SMALL AMPLITUDE
DISTURBANCES EMBEDDED IN CYCLONIC FLOW ALOFT. WILL INDICATE A 30-40%
CHANCE OF SHOWERS/STORMS SUNDAY AFT/EVE...HIGHEST IN NORTHERN
PORTIONS OF THE AREA...WITH A SLIGHT CHANCE OF SHOWERS PERSISTING
AFTER MIDNIGHT GIVEN CYCLONIC FLOW ALOFT AND DEEP MOISTURE IN THE
PRESENCE OF MARGINAL INSTABILITY. HIGHS ON SUN SIMILAR TO TODAY...
PERHAPS SLIGHTLY WARMER IF CLOUD COVER IS NOT PERVASIVE DURING THE
AFTERNOON...IN THE UPPER 80S TO NEAR 90F...WARMEST IN THE SANDHILLS
AND COASTAL PLAIN. LOWS SUN NIGHT A FEW DEGREES ABOVE NORMAL DUE TO
CLOUD COVER AND DEEP MOISTURE...IN THE LOWER 70S. -VINCENT

MONDAY WILL BEGIN WITH TWO FRONTAL SYSTEMS...ONE ON EITHER SIDE OF
THE CWA WITH THE LEAD FRONT OFF THE COAST AND THE TRAILING FRONT
BACK ACROSS THE OHIO AND LOWER MISSISSIPPI VALLEYS. MODEL FORECAST
SOUNDINGS VIEWED IN BUFKIT SHOW AN ELEVATED MIXED LAYER PRESENT FROM
ROUGHLY 800 MB UP TO 600 MB WHICH GREATLY INCREASES INSTABILITY...ON
THE ORDER OF 1500-2000 J/KG. MID-LEVEL LAPSE RATES OF 6-7 DEGREES
PER KM AND PRECIPITABLE WATER VALUES OF AROUND 1.75 INCHES ALL
INDICATE THE POTENTIAL FOR CONVECTION. HAIL AND WINDS COULD BOTH BE
A POSSIBILITY AS THE HAIL GROWTH ZONE BECOMES FAIRLY SATURATED BY
AFTERNOON. IN ADDITION DCAPE VALUES BETWEEN KRDU AND KGSO SHOULD BE
BETWEEN 1000 AND 1500 J/KG. DESPITE THIS...SHEAR WILL BE
MINIMAL...WITH BULK VALUES 15-20 KNOTS AT BEST. WHILE WIDESPREAD
CONVECTION IS NOT LIKELY...THE WILL BE A CHANCE OF SCATTERED STORMS
WITH A FEW OF THEM POTENTIALLY BECOMING SEVERE. HIGHS IN THE LOW
90S...LOWS UPPER 70S. -MLM
&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 215 AM SUNDAY...

THE LONG TERM PATTERN WILL FEATURES A PERSISTENT HIGH-AMPLITUDE
SOUTHERN ROCKY MOUNTAIN/WESTERN PLAINS RIDGE AND AN EASTERN U.S.
TROUGH THAT GRADUALLY DEAMPLIFIES AT THE END OF THE PERIOD. WHILE
THE MAIN TROUGH LIFTS NORTH LATE IN THE WORK WEEK...A MID-LEVEL
WEAKNESS AND TROUGH LINGERS WEST OF OUR REGION ON FRIDAY AND
SATURDAY.

THE UPPER LEVEL TROUGH AXIS SWINGS THROUGH CENTRAL NC ON TUESDAY AND
TUESDAY NIGHT. THE GFS IS THE FASTEST SET OF GUIDANCE WHILE THE NAM
IS THE SLOWEST WITH THE EC IN BETWEEN. THE TIMING OF THE UPPER LEVEL
TROUGH IS CONSISTENT WITH THE PASSAGE OF THE SURFACE COLD FRONT.
GIVEN THE MEAGER FLOW ALOFT AND THE WEAK SURFACE HIGH BEHIND THE
FRONT AS WELL AS GUIDANCE TRENDS WHICH SUGGEST A SLOWER FRONTAL
PASSAGE...PREFER TO USE THE SLOWER TIMING. MUCH DRIER AIR WILL BE
WORKING INTO THE WESTERN PIEDMONT BY EARLY TUESDAY AFTERNOON WHILE
THE DEEPEST MOISTURE AND INSTABILITY WILL BE LOCATED ACROSS THE
COASTAL PLAIN. HIGHS TUESDAY WILL RANGE IN THE UPPER 80S.. BUT WITH
A COOLER AIR MASS ARRIVING FROM THE WEST...LOWS TUESDAY NIGHT WILL
RANGE FROM THE LOWER 60S IN THE TRIAD TO THE UPPER 60S IN THE
SOUTHERN COASTAL PLAIN.

THE FRONT WILL CONTINUE TO PUSH SOUTH ON WEDNESDAY AND MUCH DRIER
AIR WILL WORK INTO THE REGION FROM THE NORTH. A MORNING SHOWER IS
STILL POSSIBLE IN THE SOUTHERN COASTAL PLAIN AND SANDHILLS AS THE
LOW LEVEL MOISTURE IN THAT AREA IS A BIT MORE STUBBORN. AFTERNOON
PRECIPITABLE WATER VALUES WILL RANGE FROM AROUND 0.75 INCHES NEAR
THE VA BORDER TO 1.5 INCHES TOWARD FAR SOUTHERN PORTIONS OF THE
COASTAL PLAIN. HIGHS WILL RANGE IN THE LOWER TO MID 80S AND LOWS
WEDNESDAY NIGHT WILL RANGE IN THE LOWER TO MID 60S.

FAIRLY QUIET WEATHER IS EXPECTED ON THURSDAY AND FRIDAY AS HIGH
PRESSURE LINGERS ACROSS THE OHIO VALLEY AND ANOTHER COLD FRONT
PUSHES SOUTH ACROSS THE NORTHEAST BUT STALLS IN THE MID-ATLANTIC.
THE NORTHEAST LOW LEVEL FLOW ON THURSDAY VEERS AROUND TO SOUTH AND
SOUTHEAST ON FRIDAY AND CONTINUES INTO SATURDAY. THE RESULT WILL BE
A GRADUAL INCREASE IN MOISTURE AND SOME ENHANCED UPSLOPE FLOW ACROSS
WESTERN NC. THIS PATTERN WILL LIKELY RESULT IN SOME ISOLATED
AFTERNOON AND EVENING CONVECTION...MAINLY DRIVEN BY LOCAL PROCESSES
SUCH AS DIFFERENTIAL HEATING IN THE MOUNTAINS AND ALONG THE SEA
BREEZE. OTHERWISE EXPECT PARTLY CLOUDY SKIES WITH SOME MORNING
FOG/STRATUS POSSIBLE ON FRIDAY AND SATURDAY MORNINGS. HIGHS DURING
THE PERIOD WILL GENERALLY RANGE IN THE LOWER TO MID 80S WITH MORNING
LOWS MAINLY IN THE LOWER TO MID 60S. -BLAES



&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...

CURRENT VFR CONDITIONS ARE EXPECTED TO YIELD TO IFR CONDITIONS LATE
TONIGHT... BUT CONFIDENCE IN THE TIMING AND EXTENT OF LOW CIGS/VSBYS
IS LOWER THAN USUAL. THE SURFACE MAP SHOWS THE LARGE SCALE COLD
FRONT STILL WELL TO OUR NORTH (EAST-WEST ACROSS THE LOWER GREAT
LAKES) WITH A WEAK LEE TROUGH EAST OF THE APPALACHIANS EXTENDING
THROUGH CENTRAL NC... AND THIS SETUP SHOULD CHANGE LITTLE THROUGH
THE NEXT 24 HOURS. A WARM/MOIST LOW LEVEL FLOW FROM THE SW CONTINUES
TO PUMP INCREASING LOW LEVEL MOISTURE INTO THE AREA... AND THIS WILL
LIKELY LEAD TO FORMATION OF IFR STRATUS AND MVFR FOG AS THE LOW
LEVELS STABILIZE FURTHER AND DECOUPLE. THE RESIDUAL CLOUDS FROM
EARLIER STORMS OVER THE MOUNTAINS/FOOTHILLS HAVE MOVED EAST OF THE
TRIAD AND INTO THE ERN AND SRN PIEDMONT... AND THE BRIEF CLEARING
SKIES AND MOIST GROUND AT INT/GSO (THE ONLY CENTRAL NC TAF SITES
THAT SAW RAIN TODAY) SHOULD FACILITATE DEVELOPMENT OF LOW CLOUDS AND
FOG. THIS IS SUPPORTED BY RECENT RUNS OF THE HRRR MODEL INDICATING
POSSIBLE VSBYS UNDER A HALF MILE AT INT/GSO. FARTHER EAST... THE
RESIDUAL CLOUDS DRIFTING EASTWARD SHOULD LIMIT FOG FORMATION AND
DELAY (IF NOT LIMIT) LOW CLOUD DEVELOPMENT... HOWEVER THE NAM/GFS
STATISTICAL GUIDANCE SUGGESTS THAT ALMOST THE OPPOSITE WILL OCCUR --
SHOWING CIGS DROPPING TO UNDER 1000 FT LATE TONIGHT AT THE EASTERN
TAF SITES OF RDU/RWI/FAY OVERNIGHT. WILL INDICATE A TREND TO
PREVAILING IFR CIGS/VSBYS AT INT/GSO THROUGH DAYBREAK... WITH JUST
TEMPORARY IFR CONDITIONS AT RDU/FAY/RWI FOR NOW UNTIL THE PICTURE
BECOMES CLEARER. EXPECT VFR CONDITIONS TO RESUME AT ALL SITES WITH
DAYTIME HEATING AFTER 14Z. SCATTERED SHOWERS/STORMS EXPECTED FROM
LATE MORNING THROUGH THE AFTERNOON HOURS MAY PRODUCE LOCALLY HEAVY
DOWNPOURS AND GUSTY WINDS WITH BRIEF IFR/LIFR CONDITIONS AT ANY
SITE. OTHERWISE... VFR CONDITIONS SHOULD DOMINATE THROUGH THE END OF
THE TAF VALID PERIOD (06Z EARLY MONDAY MORNING).

LOOKING BEYOND 06Z EARLY MONDAY MORNING... SHALLOW IFR FOG IS
POSSIBLE 08Z-12Z AT ALL FIVE TAF SITES AS WE MAINTAIN A LIGHT SW
SURFACE FLOW. ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS AND
STORMS ARE EXPECTED ACROSS CENTRAL NC BOTH MONDAY AND TUESDAY
AFTERNOON/EVENING... AHEAD OF A COLD FRONT APPROACHING SLOWLY FROM
THE NW... AND ANY OF THESE SHOWERS/STORMS COULD GENERATE GUSTY WINDS
AND SUB-VFR CONDITIONS WITH BRIEF HEAVY RAIN. VFR CONDITIONS ARE
LIKELY TO RETURN FOR WEDNESDAY/THURSDAY AS HIGH PRESSURE BUILDS IN
FROM THE NW WITH MUCH DRIER AIR. -GIH

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...WSS
SHORT TERM...VINCENT/MLM
LONG TERM...BLAES
AVIATION...HARTFIELD












AREA FORECAST DISCUSSION

NWS BISMARCK ND

 946 PM CDT MON SEP 2 2013

.UPDATE...
ISSUED AT 946 PM CDT MON SEP 2 2013

SURFACE HIGH PRESSURE OVER MINNESOTA WILL CONTINUE TO MOVE SOUTH
AND EAST TONIGHT AS LOW PRESSURE IN EASTERN MONTANA MOVES INTO THE
WESTERN DAKOTAS BY 12 UTC TUESDAY. INCREASING MID AND HIGH LEVEL
CLOUDINESS CONTINUES TO SPILL OVER THE WESTERN RIDGE INTO THE
DAKOTAS AND WILL INCREASE CLOUD COVER ACROSS THE WEST TONIGHT.
LATEST 01 UTC HRRR AND RAP INDICATE SHOWERS MOVING INTO THE FAR
WEST AROUND 12 UTC TUESDAY. WILL KEEP THE OVERNIGHT PERIOD DRY FOR
NOW BUT WILL INTRODUCE ISOLATED THUNDERSHOWERS INTO THE FAR
SOUTHWEST AT 12 UTC...A COUPLE HOURS EARLIER THAN THE PREVIOUS
FORECAST. OTHERWISE NO CHANGES TO THE GOING FORECAST. CURRENT
FORECAST LOW TEMPERATURES LOOK REASONABLE WITH TUESDAY MORNING
LOWS A GOOD 5-10 DEGREES WARMER THAN THIS MORNING.

UPDATE ISSUED AT 641 PM CDT MON SEP 2 2013

NO UPDATES THIS EVENING OTHER THAN POPULATING WITH THE LATEST
SENSIBLE WEATHER GRIDS AND INTERPOLATING THROUGH MID EVENING. HIGH
PRESSURE OVER THE EASTERN DAKOTAS WILL CONTINUE TO MOVE EAST AS
LOW PRESSURE DEVELOPS IN EASTERN MONTANA.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)

ISSUED AT 303 PM CDT MON SEP 2 2013

A RETURN TO WARM TEMPERATURES WILL HIGHLIGHT THE SHORT TERM
FORECAST.

THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON LEE SURFACE
TROUGHING ACROSS EASTERN MONTANA AND WYOMING DEEPENING THROUGH
TONIGHT...THEN FILLING ON TUESDAY AS STRONG SURFACE HIGH PRESSURE
PROPAGATES FROM CANADA INTO THE NORTHERN PLAINS LATE IN THE DAY
ON TUESDAY WITH A STRONG SURFACE COLD FRONT ON THE LEADING EDGE OF
THE HIGH PRESSURE MAKING IT INTO APPROXIMATELY THE US HIGHWAY 2
CORRIDOR BY LATE AFTERNOON. HIGHS ON TUESDAY ARE FORECAST TO CLIMB
INTO THE UPPER 80S AND LOWER 90S SOUTH OF THE AFOREMENTIONED COLD
FRONT. ISOLATED THUNDERSTORMS ARE POSSIBLE WEST OF HIGHWAY 83
TUESDAY AFTERNOON AS THE SHORTWAVE CURRENTLY ACROSS NORTHEAST UTAH
CRESTS THE RIDGE LATE TUESDAY AFTERNOON INTO WESTERN NORTH DAKOTA.
SHEAR AND INSTABILITY PROFILES ARE NOT SUPPORTIVE OF SEVERE
CONVECTION.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)

ISSUED AT 303 PM CDT MON SEP 2 2013

A BACKDOOR COLD FRONT MOVING THROUGH THE NORTHERN PLAINS TUESDAY
NIGHT WILL BRING COOLER TEMPERATURES TO WEST AND CENTRAL NORTH
DAKOTA ON WEDNESDAY...STILL ABOUT 5 DEGREES ABOVE NORMAL...WITH
HIGHS FROM THE MID 70S NORTH TO MID 80S SOUTH. THE WARMING TREND
THEN RESUMES THURSDAY INTO FRIDAY AS THE UPPER LEVEL RIDGE SHIFTS
EAST INTO THE GREAT PLAINS. STILL EXPECTING MOSTLY DRY CONDITIONS
OVER NORTH DAKOTA THROUGH THURSDAY NIGHT WITH A DRY NORTHWEST FLOW
ALOFT. MAY SEE A FEW SCATTERED SHOWERS/ISOLATED T-STORMS TUESDAY
EVENING AS AN EMBEDDED S/WV IMPULSE SLIDES EAST-SOUTHEAST THROUGH
THE DAKOTAS...AND AS THE COLD FRONT MOVES SOUTH ACROSS THE STATE.
WHILE INSTABILITY AND SHEAR PARAMETERS DO NOT INDICATE SEVERE
WEATHER...CANNOT COMPLETELY RULE OUT A STRONGER STORM OR TWO NEAR
THE COLD FRONT IN THE EVENING WHERE THE 12Z ECMWF INDICATES A
BRIEF PERIOD OF MODEST INSTABILITY NEAR 1500 J/KG.

AS WE HEAD INTO THE COMING WEEKEND...MODELS PROJECT THE RIDGE TO
BREAKDOWN AS A CLOSED UPPER LOW (NOW OFF THE PACIFIC NORTHWEST
U.S. COAST) MOVES INLAND THURSDAY...THEN EAST ACROSS THE
ROCKIES/TOWARDS THE NORTHERN PLAINS FRI NIGHT-SAT...AND EVENTUALLY
INTO THE REGION SUN-MON. AS THIS FEATURE APPROACHES...WILL START
TO SEE INCREASING CHANCES FOR PRECIPITATION WITH SLIGHT CHANCES
FRI/FRI NIGHT...AND BETTER CHANCES SATURDAY THROUGH MONDAY. THIS
FEATURE IS ALSO EXPECTED TO BRING COOLER WEATHER TO THE NORTHERN
PLAINS REGION...WHICH AT THIS TIME STILL LOOKS TO OCCUR POSSIBLY
SUNDAY WITH A BETTER CHANCE OF COOLER WEATHER NEXT SUNDAY NIGHT
INTO THE EARLY PORTIONS OF THE FOLLOWING WORK WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 946 PM CDT MON SEP 2 2013

A NORTHERN STREAM WAVE TRACKING EAST ACROSS CENTRAL CANADA WILL
DRAG A COLD FRONT SOUTH ACROSS THE FORECAST AREA ON TUESDAY. IN
ADDITION...ANOTHER WAVE IS FORECAST TO MOVE THROUGH THE WESTERN
RIDGE AND INTO THE WESTERN DAKOTAS ON TUESDAY. THESE FEATURES WILL
PROVIDE A SLIGHT CHANCE OF THUNDERSTORMS ON TUESDAY MAINLY WEST OF
THE HIGHWAY 83 CORRIDOR. HOWEVER COVERAGE WILL BE ISOLATED AND
THUS WILL NOT MENTION A VCTS AT TAF SITES AT THIS TIME. OTHERWISE
VFR CONDITIONS AREA FORECAST. SOUTHERLY FLOW ACROSS THE AREA WILL
SHIFT NORTH AT KISN AND KMOT TUESDAY AFTERNOON BEHIND THE COLD
FRONT.


&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...TWH
SHORT TERM...AYD
LONG TERM...NH
AVIATION...TWH







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 118 PM CDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 118 PM CDT SUN SEP 1 2013

NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE. THE MORNING
STRATUS FIELD CONTINUES TO SLOWLY LIFT AND SCATTER AND EXPECT THIS
TREND TO CONTINUE THROUGH THE AFTERNOON...SUPPORTED BY THE 12 UTC
DETERMINISTIC LOW LEVEL MOISTURE FIELDS. OTHERWISE...THE FORECAST
IS ON TRACK.

UPDATE ISSUED AT 1013 AM CDT SUN SEP 1 2013

GIVEN VISIBLE SATELLITE TRENDS THROUGH 15 UTC...INCREASED CLOUD
COVER THROUGH 18 UTC AS THE BREAK UP AND LIFTING OF THE STRATUS
FIELD IS TAKING LONGER THAN PREVIOUSLY FORECAST. THIS IS
CONFIRMED BY THE 12 UTC HRRR LOW LEVEL CLOUD COVER FORECASTS.
OTHERWISE...THE REMAINDER OF THE FORECAST IS ON TRACK.

UPDATE ISSUED AT 655 AM CDT SUN SEP 1 2013

NO SIGNIFICANT CHANGES MADE TO THE FORECAST. TEMPERATURES ARE
RUNNING A LITTLE WARMER THAN FORECAST AT LOCATIONS UNDER CLOUD
COVER. OTHERWISE...THE FORECAST IS ON TRACK. SATELLITE CONTINUES
TO SHOW CLOUDS PUSHING SOUTHWARD...ALMOST TO BISMARCK AT THIS
TIME. OBS INDICATING CEILINGS WITH THESE CLOUDS AROUND 1000-1500
FEET.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 301 AM CDT SUN SEP 1 2013

DRIER AND COOLER WEATHER WILL HIGHLIGHT THE SHORT TERM FORECAST.
CLOUD COVER EXTENT AND TIMING IS THE MAIN FORECAST CONCERN...AS THIS
WILL IMPACT MAXIMUM TEMPERATURES.

CURRENTLY...HIGH PRESSURE WAS CENTERED OVER SOUTHERN SASKATCHEWAN
WITH THE HIGH AXIS EXTENDING INTO EASTERN MONTANA. AN AREA OF
VFR/MVFR CLOUDS OVER SOUTHERN SASKATCHEWAN AND MANITOBA HAD EDGED
INTO NORTHERN NORTH DAKOTA.

MODELS WERE SUGGESTING THESE CLOUDS WILL MOVE SOUTH ACROSS THE STATE
THIS MORNING. THE HIGH CENTER IS FORECAST TO MOVE SOUTHEAST AND BY
EARLY AFTERNOON BE CENTERED OVER LAKE WINNIPEG INTO THE JAMES/RED
RIVER VALLEYS. NORTHWEST WINDS SHOULD BECOME NORTH...THEN NORTHEAST
INTO THE LATER MORNING HOURS. AS THE HIGH MOVES SOUTHEAST...MODELS
ARE SUGGESTING CLEARING SKIES NEAR THE HIGH CENTER AND ASSOCIATED
CLOUDS REMAINING ON THE WESTERN/SOUTHERN PERIPHERY OF THE HIGH LATER
THIS MORNING AND EARLY AFTERNOON TODAY BEFORE FINALLY DISSIPATING
DURING THE MID-LATE AFTERNOON HOURS. THIS WOULD RESULT IN CLEARING
SKIES OVER THE TURTLE MOUNTAINS...WITH PARTLY TO MOSTLY CLOUDY SKIES
OVER MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH EARLY
AFTERNOON...THEN SCATTERING OUT DURING THE MID-LATE AFTERNOON. THIS
RESULTS IN AFTERNOON HIGH TEMPERATURES A TAD LOWER THAN THE PREVIOUS
FORECAST. SO...HIGHS FROM THE UPPER 60S IN THE TURTLE MOUNTAINS TO
THE UPPER 70S IN THE SOUTHWEST.

TONIGHT CLEAR SKIES ARE EXPECTED. THE HIGH CENTER IS FORECAST TO
SETTLE OVER MINNESOTA AND THE FAR EASTERN DAKOTAS...WITH RETURN
SOUTHEASTERLY FLOW DEVELOPING OVER THE WESTERN DAKOTAS. THUS LOWER
MINIMUM TEMPERATURES OVER THE JAMES RIVER BASIN - CLEAR SKIES AND
LIGHT WINDS CLOSER TO THE HIGH CENTER - EXPECTING LOWS IN THE MID
40S. LOW TO MID 50S FOR LOWS IN THE WEST FARTHER FROM THE HIGH
CENTER AND WHERE SOUTHEASTERLY WINDS SHOULD KEEP THE LOWER
ATMOSPHERE MIXED SOMEWHAT AND KEEP THE TEMPERATURES FROM LOWERING
INTO THE 40S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 301 AM CDT SUN SEP 1 2013

MAJORITY OF THE EXTENDED PERIOD WILL BE DOMINATED BY STRONG RIDGE
THAT EXTENDS FROM AROUND NEW MEXICO THROUGH ALBERTA/SASKATCHEWAN.
LITTLE CHANGE IN THE PATTERN EXPECTED THROUGH MUCH OF THE WEEK
WITH THE RIDGE LOCATED BETWEEN DEEP UPPER LOW JUST OFF PAC NW
COAST AND TROUGH OVER EASTERN NORTH AMERICA. THIS WILL RESULT IN
MOSTLY DRY CONDITIONS AND TEMPERATURES RUNNING WELL ABOVE NORMAL
WITH HIGHS IN THE 80S TO LOW 90S.

TOWARD THE END OF THE WEEK THE PAC NW LOW BEGINS MOVING INLAND
REACHING MONTANA BY SAT NIGHT PER 00Z GFS/ECMWF. ONE WAVE
DEPICTED BY GFS/ECMWF RIDES RIDGE AND APPROACHES ND BY TUESDAY
RESULTING IN SOME LOW POPS FOR MAINLY WESTERN ND TUE AND TUE
NIGHT. BETTER LIKELIHOOD OF PRECIPITATION BY SATURDAY AS THE UPPER
LOW APPROACHES THE REGION. GFS/ECMWF INDICATE SURFACE LOW IN
VICINITY OF EASTERN MONTANA SATURDAY AFTERNOON LEAVING NORTH
DAKOTA IN WARM SECTOR WITH GFS INDICATING AXIS OF INSTABILITY

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 118 PM CDT SUN SEP 1 2013

THE MORNING STRATUS FIELD ACROSS WESTERN AND CENTRAL NORTH DAKOTA
CONTINUES TO LIFT AND SCATTER. THIS TREND WILL CONTINUE WITH VFR
CONDITIONS FOR THE 18 UTC TAFS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...JNS
AVIATION...AYD







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1013 AM CDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 1013 AM CDT SUN SEP 1 2013

GIVEN VISIBLE SATELLITE TRENDS THROUGH 15 UTC...INCREASED CLOUD
COVER THROUGH 18 UTC AS THE BREAK UP AND LIFTING OF THE STRATUS
FIELD IS TAKING LONGER THAN PREVIOUSLY FORECAST. THIS IS
CONFIRMED BY THE 12 UTC HRRR LOW LEVEL CLOUD COVER FORECASTS.
OTHERWISE...THE REMAINDER OF THE FORECAST IS ON TRACK.

UPDATE ISSUED AT 655 AM CDT SUN SEP 1 2013

NO SIGNIFICANT CHANGES MADE TO THE FORECAST. TEMPERATURES ARE
RUNNING A LITTLE WARMER THAN FORECAST AT LOCATIONS UNDER CLOUD
COVER. OTHERWISE...THE FORECAST IS ON TRACK. SATELLITE CONTINUES
TO SHOW CLOUDS PUSHING SOUTHWARD...ALMOST TO BISMARCK AT THIS
TIME. OBS INDICATING CEILINGS WITH THESE CLOUDS AROUND 1000-1500
FEET.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 301 AM CDT SUN SEP 1 2013

DRIER AND COOLER WEATHER WILL HIGHLIGHT THE SHORT TERM FORECAST.
CLOUD COVER EXTENT AND TIMING IS THE MAIN FORECAST CONCERN...AS THIS
WILL IMPACT MAXIMUM TEMPERATURES.

CURRENTLY...HIGH PRESSURE WAS CENTERED OVER SOUTHERN SASKATCHEWAN
WITH THE HIGH AXIS EXTENDING INTO EASTERN MONTANA. AN AREA OF
VFR/MVFR CLOUDS OVER SOUTHERN SASKATCHEWAN AND MANITOBA HAD EDGED
INTO NORTHERN NORTH DAKOTA.

MODELS WERE SUGGESTING THESE CLOUDS WILL MOVE SOUTH ACROSS THE STATE
THIS MORNING. THE HIGH CENTER IS FORECAST TO MOVE SOUTHEAST AND BY
EARLY AFTERNOON BE CENTERED OVER LAKE WINNIPEG INTO THE JAMES/RED
RIVER VALLEYS. NORTHWEST WINDS SHOULD BECOME NORTH...THEN NORTHEAST
INTO THE LATER MORNING HOURS. AS THE HIGH MOVES SOUTHEAST...MODELS
ARE SUGGESTING CLEARING SKIES NEAR THE HIGH CENTER AND ASSOCIATED
CLOUDS REMAINING ON THE WESTERN/SOUTHERN PERIPHERY OF THE HIGH LATER
THIS MORNING AND EARLY AFTERNOON TODAY BEFORE FINALLY DISSIPATING
DURING THE MID-LATE AFTERNOON HOURS. THIS WOULD RESULT IN CLEARING
SKIES OVER THE TURTLE MOUNTAINS...WITH PARTLY TO MOSTLY CLOUDY SKIES
OVER MUCH OF WESTERN AND CENTRAL NORTH DAKOTA THROUGH EARLY
AFTERNOON...THEN SCATTERING OUT DURING THE MID-LATE AFTERNOON. THIS
RESULTS IN AFTERNOON HIGH TEMPERATURES A TAD LOWER THAN THE PREVIOUS
FORECAST. SO...HIGHS FROM THE UPPER 60S IN THE TURTLE MOUNTAINS TO
THE UPPER 70S IN THE SOUTHWEST.

TONIGHT CLEAR SKIES ARE EXPECTED. THE HIGH CENTER IS FORECAST TO
SETTLE OVER MINNESOTA AND THE FAR EASTERN DAKOTAS...WITH RETURN
SOUTHEASTERLY FLOW DEVELOPING OVER THE WESTERN DAKOTAS. THUS LOWER
MINIMUM TEMPERATURES OVER THE JAMES RIVER BASIN - CLEAR SKIES AND
LIGHT WINDS CLOSER TO THE HIGH CENTER - EXPECTING LOWS IN THE MID
40S. LOW TO MID 50S FOR LOWS IN THE WEST FARTHER FROM THE HIGH
CENTER AND WHERE SOUTHEASTERLY WINDS SHOULD KEEP THE LOWER
ATMOSPHERE MIXED SOMEWHAT AND KEEP THE TEMPERATURES FROM LOWERING
INTO THE 40S.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 301 AM CDT SUN SEP 1 2013

MAJORITY OF THE EXTENDED PERIOD WILL BE DOMINATED BY STRONG RIDGE
THAT EXTENDS FROM AROUND NEW MEXICO THROUGH ALBERTA/SASKATCHEWAN.
LITTLE CHANGE IN THE PATTERN EXPECTED THROUGH MUCH OF THE WEEK
WITH THE RIDGE LOCATED BETWEEN DEEP UPPER LOW JUST OFF PAC NW
COAST AND TROUGH OVER EASTERN NORTH AMERICA. THIS WILL RESULT IN
MOSTLY DRY CONDITIONS AND TEMPERATURES RUNNING WELL ABOVE NORMAL
WITH HIGHS IN THE 80S TO LOW 90S.

TOWARD THE END OF THE WEEK THE PAC NW LOW BEGINS MOVING INLAND
REACHING MONTANA BY SAT NIGHT PER 00Z GFS/ECMWF. ONE WAVE
DEPICTED BY GFS/ECMWF RIDES RIDGE AND APPROACHES ND BY TUESDAY
RESULTING IN SOME LOW POPS FOR MAINLY WESTERN ND TUE AND TUE
NIGHT. BETTER LIKELIHOOD OF PRECIPITATION BY SATURDAY AS THE UPPER
LOW APPROACHES THE REGION. GFS/ECMWF INDICATE SURFACE LOW IN
VICINITY OF EASTERN MONTANA SATURDAY AFTERNOON LEAVING NORTH
DAKOTA IN WARM SECTOR WITH GFS INDICATING AXIS OF INSTABILITY

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 1013 AM CDT SUN SEP 1 2013

MVFR STRATUS IMPACTING KMOT/KISN/KBIS WILL SLOWLY LIFT AND BREAK
UP THROUGH THE 16-18 UTC TIME FRAME. OTHERWISE...VFR CONDITIONS ARE
FORECAST WITH HIGH PRESSURE IN PLACE.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...AYD
SHORT TERM...JV
LONG TERM...JNS
AVIATION...AYD







AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 633 AM CDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 630 AM CDT SUN SEP 1 2013

WE WILL INCREASE CLOUD COVER A BIT THIS MORNING BEFORE CLEARING
MOVES IN FROM THE NW. THE LATEST HRRR ACTUALLY HOLDS ONTO CLOUDS
LONGER TODAY...AND IT COULD BE CLOUDY A BIT LONGER THAN EXPECTED.
FOR NOW WILL BE MORE OPTIMISTIC WITH CLEARING PER THE NAM...BUT
MAY HAVE TO INCREASE CLOUDS TODAY IF THIS TREND CONTINUES.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 310 AM CDT SUN SEP 1 2013

THE MAIN CHALLENGE WILL BE TEMPS WITH DRY WEATHER THROUGH AT
LEAST FRIDAY NIGHT. MODELS ARE IN VERY GOOD OVERALL AGREEMENT AND
NO REAL PREFERENCE THIS MORNING...SO A MODEL BLEND WILL BE
UTILIZED THIS MORNING.

FOR TODAY...A STRONG COLD FRONT HAS USHERED IN UNSEASONABLY COOL
AIR FOR THE FIRST DAY OF SEPTEMBER. IT WILL BE BREEZY THROUGH MID
AFTERNOON WITH ABOUT 25KT TO MIX...AND TEMPS WILL STRUGGLE TO
REACH 70 IN MOST AREAS. THERE WILL BE CLOUDS FOR THE MORNING HOURS
NEAR THE STRONGEST COLD ADVECTION...WITH PLENTIFUL SUNSHINE AND
HIGH CONVECTIVE TEMPS THIS AFTERNOON FOR ALL BUT THE FAR EAST.

FOR TONIGHT...COLD HIGH PRESSURE WILL SETTLE OVER THE REGION...AND
EXPECT LOWS TO FALL INTO THE LOW/MID 40S FOR ALL AREAS. THERE
COULD BE SOME AREAS AROUND 40 WHERE WINDS DECOUPLE QUICKLY THIS
EVENING...MOST LIKELY IN THE NORTHERN RED RIVER VALLEY.

ON MONDAY...TEMPS WILL WARM TO AROUND NORMAL WITH PLENTY OF
SUNSHINE EXPECTED. SFC HIGH PRESSURE WILL MOVE INTO WESTERN
MN...AS RETURN FLOW DEVELOPS OVER THE CENTRAL DAKOTAS.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 310 AM CDT SUN SEP 1 2013

FOR MONDAY NIGHT...IT WILL BE WARMER THAN SUNDAY NIGHT...WITH
SOUTHERLY WINDS INCREASING A BIT LATE IN THE WEST.

FOR TUE...IT WILL WARM ABOVE NORMAL WITH UPPER RIDGING AND 850MB
TEMPS WARMING TO AROUND +20C IN THE WEST.

WEDNESDAY THROUGH SATURDAY NIGHT...TRANQUIL CONDITIONS WILL
CONTINUE. 500 TO 300 HPA RIDGE AXIS REMAINS ACROSS EASTERN MT/
WESTERN DAKOTAS...BUT MID-LEVEL THERMAL AXIS PUSHES EAST A BIT EACH
DAY...SO THAT DAYTIME HIGHS CLIMB BACK INTO THE MID TO UPPER 80S BY
FRIDAY. A DEGREE OR TWO OF COOLING IS POSSIBLE BY SATURDAY AS THE
RIDGE BEGINS TO BREAK-DOWN A BIT IN ADVANCE OF THE NEXT PACIFIC
SHORT-WAVE. DRY CONDITIONS WILL CONTINUE THROUGH SATURDAY GIVEN
PERSISTENT SURFACE HIGH PRESSURE WITH THE NEXT BEST CHANCE FOR
SHOWERS AND THUNDERSTORMS SATURDAY NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 630 AM CDT SUN SEP 1 2013

THE BIGGEST CHALLENGE WILL BE WHEN CLEARING WILL MOVE INTO THE
AREA. EXPECT THE WEST AND NORTH TO CLEAR FIRST...WITH MFVR AND
LOCAL IFR CONDITIONS THIS MORNING PERSISTING IN THE EAST.
NORTHERLY WINDS WILL GUST OVER 20KT IN ALL AREAS THROUGH MID
AFTERNOON BEFORE QUICKLY SUBSIDING AROUND SUNSET.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$

UPDATE...DK
SHORT TERM...DK
LONG TERM...DK/ROGERS
AVIATION...DK







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1246 AM CDT SUN SEP 1 2013

.UPDATE...
ISSUED AT 1245 AM CDT SUN SEP 1 2013

CURRENTLY...HIGH PRESSURE WAS CENTERED OVER CENTRAL/SOUTHERN
SASKATCHEWAN WITH THE HIGH AXIS EXTENDING INTO EASTERN MONTANA. AN
AREA OF VFR/MVFR CLOUDS OVER SOUTHERN SASKATCHEWAN AND MANITOBA HAD
EDGED INTO FAR NORTHERN NORTH DAKOTA. MODELS STILL SUGGESTING THESE
CLOUDS WILL MOVE SOUTH ACROSS THE STATE OVERNIGHT. THE HIGH IS
FORECAST TO MOVE SOUTHEAST AND BY EARLY AFTERNOON BE CENTERED OVER
LAKE WINNIPEG INTO THE JAMES/RED RIVER VALLEYS. NORTHWEST WINDS
SHOULD BECOME NORTH...THEN NORTHEAST OVERNIGHT INTO THE LATER
MORNING HOURS. LOWERED OVERNIGHT LOWS A BIT...ESPECIALLY IN THE
SOUTH WHICH SHOULD REMAIN CLOUD-FREE UNTIL LATER TONIGHT. CURRENT
FORECAST LOOKS ON TRACK.

UPDATE ISSUED AT 954 PM CDT SAT AUG 31 2013

CLEAR SKIES ACROSS ALL BUT THE FAR NORTHWEST THIS EVENING WITH
DIMINISHING NORTH TO NORTHWEST WINDS. EXTENSIVE CLOUD COVER ACROSS
SOUTHERN SASKATCHEWAN AND MANITOBA IS PUSHING SOUTH AND IS
EXPECTED TO DROP SOUTH ACROSS WESTERN AND CENTRAL NORTH DAKOTA
LATE TONIGHT. LATEST 01 SEP 00Z NAM AND RUC GUIDANCE SUGGESTS
HIGHEST 925-850MB RH SHOULD CONTINUE TO PUSH SOUTH THROUGH EASTERN
PORTIONS OF THE CWA...BUT LINGER IN THE WEST...MAINLY FROM ISN TO
BETWEEN BISMARCK AND DICKINSON ON THE BACK SIDE OF THE SURFACE
HIGH. ADJUSTED CLOUD COVER BASED ON LATEST LOW LEVEL RH GUIDANCE.
OTHERWISE A QUIET NIGHT WITH DIMINISHING WINDS AND COMFORTABLE
TEMPERATURES MAINLY IN THE 50S.

UPDATE ISSUED AT 638 PM CDT SAT AUG 31 2013

MUCH COOLER AIR BEHIND AN EXITING COLD FRONT WILL CONTINUE TO
SPILL ACROSS WESTERN AND CENTRAL NORTH DAKOTA TONIGHT. AN UPPER
LEVEL LOW ACROSS MANITOBA HAS MOVED FAR ENOUGH EAST THAT EARLY
EVENING SHOWERS AND THUNDERSTORMS ACROSS THE NORTH CENTRAL. OTHER
THAN REMOVING POPS NORTH CENTRAL AND MINOR CLOUD COVER
ADJUSTMENTS...THE CURRENT FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)

ISSUED AT 250 PM CDT SAT AUG 31 2013

DRIER AND COOLER AIR WILL HIGHLIGHT THE SHORT TERM FORECAST.

AS OF 20 UTC...THE COLD FRONT HAS CLEARED THE CWA WITH LOW LEVEL
DRY AND COLD AIR ADVECTION ACROSS WESTERN AND CENTRAL NORTH DAKOTA
AND WIDESPREAD WIND GUSTS OF 25-30 KTS IN POST FRONTAL MIXING.
DID ADD A MENTION OF ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE
NORTH CENTRAL THIS AFTERNOON AND EARLY EVENING WITH THE UPPER
LEVEL LOW THAT IS PROPAGATING SOUTHEAST OUT OF FAR SOUTHEAST
SASKATCHEWAN. ANY CONVECTION THAT DOES FORM WILL FADE WITH SUNSET.
AN EXPANSE OF STRATUS IS EXPECTED TO OVERSPREAD AREAS ALONG AND
NORTH OF I-94 TONIGHT...WHICH WILL HELP TO KEEP OVERNIGHT LOWS IN
THE 50S. A QUIET A REFRESHINGLY COOL DAY IS EXPECTED SUNDAY WITH
HIGHS IN THE 70S WITH HIGH PRESSURE IN PLACE. GIVEN GOOD
AGREEMENT...A BLEND OF THE 12 UTC GUIDANCE SUITE WAS USED FOR ALL
FIELDS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)

ISSUED AT 250 PM CDT SAT AUG 31 2013

AFTER A COOL AND DRY SUNDAY...WILL SEE A WARMING TREND BACK TO
ABOVE NORMAL TEMPERATURES THROUGH THE COMING WORK WEEK AS THE
CENTRAL U.S. UPPER RIDGE REBUILDS/AMPLIFIES FROM ACROSS THE
ROCKIES NORTH INTO THE CANADIAN HIGH PLAINS...BRINGING WAA BACK
EAST INTO THE DAKOTAS. EXPECT MOSTLY DRY CONDITIONS OVER NORTH
DAKOTA THROUGH THURSDAY NIGHT WITH A DRY NORTHWEST FLOW ALOFT.
THE EXCEPTION MAY BE THE TUESDAY AFTERNOON THROUGH WEDNESDAY
NIGHT PERIOD WHEN MODELS PROJECT AN EMBEDDED S/WV IMPULSE MOVING
THROUGH THE RIDGE FROM ACROSS SOUTHERN MONTANA EAST INTO THE
DAKOTAS. HAVE CONFINED SLIGHT CHANCE POPS FOR NOW TUESDAY NIGHT
THROUGH WED NIGHT. THE LATEST ECMWF (12Z) NOW BRINGS THIS FEATURE
TO THE ND/MT BORDER BY 00Z WED...SO FUTURE UPDATED FORECASTS MAY
NEED TO ADD SOME MENTION OF THUNDERSTORMS STARTING TUESDAY
AFTERNOON ACROSS THE WEST.

AS WE HEAD INTO THE LATER PORTIONS OF THE WORK WEEK AND THE FIRST
HALF OF NEXT WEEKEND...MODELS PROJECT THE RIDGE TO BREAKDOWN AS A
CLOSED UPPER LOW (NOW OFF THE NORTHWEST U.S. COAST) MOVES INLAND
SOMETIME THURSDAY NIGHT OR FRIDAY...THEN EAST TOWARDS THE NORTHERN
PLAINS SOMETIME FRI-SUN. LATEST GFS/ECMWF DIFFER ON THE TIMING OF
THIS FEATURE...SO LOTS OF UNCERTAINTY STILL IN PLAY. EVENTUALLY
THIS FEATURE WILL BE THE FOCUS OF LATER FORECASTS AS IT IS
EXPECTED TO BRING COOLER WEATHER AND INCREASED CHANCES FOR
PRECIPITATION TO OUR REGION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1245 AM CDT SUN SEP 1 2013

LATEST GUIDANCE IS STILL SUGGESTING LOW VFR TO MVFR CEILINGS
DROPPING SOUTH INTO THE FORECAST AREA OVERNIGHT AND SUNDAY MORNING.
THEN IMPROVING CEILINGS LATE SUNDAY MORNING WITH A NORTH FLOW
SHIFTING EAST TO SOUTHEAST SUNDAY AFTERNOON. BROUGHT VFR CIGS TO
KISN/KMOT AT 06Z...THEN MVFR BY 09Z...THEN IMPROVING TO VFR CIGS BY
AROUND 16Z. SOUTHERN TAF SITES KDIK/KBIS/KJMS...BROUGHT VFR CIGS BY
09Z/10Z THEN MVFR BY AROUND 12Z...IMPROVING TO VFR BY 18Z.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JV
SHORT TERM...AYD
LONG TERM...NH
AVIATION...JV







AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 303 PM EDT SUN SEP 1 2013

.SYNOPSIS...
UPPER LEVEL DISTURBANCES TODAY. COLD FRONT MONDAY NIGHT. COOLER
AND DRIER AIRMASS MID WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
WE WILL CONTINUE IN A WEST TO NORTHWEST FLOW ALOFT REGIME WITH UPPER
DISTURBANCES ROTATING ACROSS THE REGION. ALTHOUGH THE ATMOSPHERE IS
VERY MOIST AND CONDITIONALLY UNSTABLE...THE PROSPECT FOR CONVECTION
STILL DEPENDS ON MESOSCALE INFLUENCES. THE MOST DOMINANT INFLUENCE
WITH THIS OVERALL PATTERN OVER THE PAST 36 HOURS HAS BEEN THE VERY
WELL DEFINED LOW LEVEL BOUNDARY FROM PREVIOUS CONVECTION THAT HAS
BEEN LAID OUT WELL TO THE SOUTH OVER THE TENNESSEE VALLEY REGION
ON INTO SOUTHWEST VIRGINIA. THIS HAS ESTABLISHED THE MAIN BAND OF
CONVECTION WITHIN THIS PATTERN TO REMAIN MOSTLY SOUTH OF OUR AREA.
THUS...EVEN WITH A WELL DEFINED VORT MAX LIFTING UP ACROSS THE
AREA THIS AFTERNOON AND EARLY EVENING...MOST OF THE ORGANIZED
CONVECTION WITH THIS FEATURE WILL REMAIN OVER THE SOUTHERN AND
CENTRAL MOUNTAINS. ELSEWHERE...ONLY SCATTERED AFTERNOON CONVECTION
CAN BE EXPECTED. THERE ARE A LOT OF CLOUDS WITH THIS VORT SO THAT
CONVECTION MAY BE FURTHER LIMITED IN SCOPE AND INTENSITY THIS
AFTERNOON AND EVENING. STRONGLY WENT WITH THE HRRR MODEL THROUGH
THIS EVENING.

IN ANY CASE...THE VORT QUICKLY EXITS INTO VIRGINIA THIS EVENING...AND
WITH LOSS OF HEATING...ANY CONVECTION WILL QUICKLY DIE DOWN.
STILL...WILL LEAVE MIN POPS OVERNIGHT FOR NOCTURNAL POTENTIAL IN THE
MOIST ATMOSPHERE.

FOR MONDAY...A COLD FRONT WILL APPROACH FROM THE WEST...BUT WILL NOT
REACH OUR AREA UNTIL JUST AFTER THIS PERIOD. SO AGAIN...CONVECTION
WILL BE DEPENDENT ON FEATURES AHEAD OF THE MAIN SHORT WAVE
SUPPORTING THE FRONT. WILL KEEP THE BEST POPS AGAIN...SIMILAR TO
TODAY...IN THE SOUTH AND EAST IN THE AFTERNOON AS THE ONGOING
CONVECTIVE SURFACE BOUNDARY STRUGGLES TO LIFT NORTHWARD. AND
AGAIN...CLOUDS WILL BE A BIG FACTOR TO POTENTIALLY CURB CONVECTION.

FOR TEMPS...TOOK A BLEND OF THE MODELS...WHICH HAS BEEN THE BEST WAY
SO FAR.

&&

.SHORT TERM /MONDAY NIGHT 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 /19Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THROUGH 18Z MONDAY...
SHORT WAVE CROSSES AREA THIS AFTERNOON...WITH MOST OF THE CONVECTION IN
THE MOUNTAINS...SCATTERED AFTERNOON DIURNAL CONVECTION
ELSEWHERE. EXPECT VFR OUTSIDE OF CONVECTION...EXCEPT WILL INCLUDE
PREVAILING MVFR IN CENTRAL AND SOUTHERN MOUNTAINS...ESPECIALLY AT
BKW GIVEN THE SUSTAINED HIGH POPS.

BULK OF CONVECTION WILL DIE DOWN AFTER 03Z...BUT STILL CANNOT
TOTALLY PULL POPS GIVEN THE MAIN SHORT WAVE AND FRONT ARE STILL TO
THE WEST. WILL KEEP ISOLATED. FOG DEVELOPMENT TONIGHT WILL DEPEND ON
THE AMOUNT OF CLEARING AND LOCATION OF PRECIPITATION DURING THE
DAY...BUT THINK MOST SITES WILL SEE ENOUGH STARS TO BRING IN MVFR TO
IFR FOG AFTER 05Z...ESPECIALLY ALONG RIVERS AND IN VALLEYS WHERE IT
RAINS TODAY.

AFTER 12Z...VFR CEILINGS PREVAILING WITH SCATTERED SHOWERS SPREADING
FROM WEST TO EAST.



FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: FOG DEVELOPMENT AND DENSITY TONIGHT MAY VARY
DUE MAINLY TO CLOUD COVER.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    M    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    M    H    H    H    H    H    M    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN CONVECTION THROUGH AT LEAST MONDAY. IFR FOG POSSIBLE
TUESDAY AND WEDNESDAY MORNINGS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...JMV/26
NEAR TERM...JMV
SHORT TERM...26
LONG TERM...26
AVIATION...JMV









AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 248 PM EDT SUN SEP 1 2013

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE TODAY...AND A COLD FRONT APPROACHING
MONDAY...CONTINUE THE CHANCE FOR THUNDERSTORMS.  THE PASSAGE OF THE
FRONT BRINGS AN END TO THE THUNDERSTORMS FOR THE SHORT WORK WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
WE WILL CONTINUE IN A WEST TO NORTHWEST FLOW ALOFT REGIME WITH UPPER
DISTURBANCES ROTATING ACROSS THE REGION. ALTHOUGH THE ATMOSPHERE IS
VERY MOIST AND CONDITIONALLY UNSTABLE...THE PROSPECT FOR CONVECTION
STILL DEPENDS ON MESOSCALE INFLUENCES. THE MOST DOMINANT INFLUENCE
WITH THIS OVERALL PATTERN OVER THE PAST 36 HOURS HAS BEEN THE VERY
WELL DEFINED LOW LEVEL BOUNDARY FROM PREVIOUS CONVECTION THAT HAS
BEEN LAYED OUT WELL TO THE SOUTH OVER THE TENNESSEE VALLEY REGION ON
INTO SOUTHWEST VIRGINIA. THIS HAS ESTABLISHED THE MAIN BAND OF
CONVECTION WITHIN THIS PATTERN TO REMAIN MOSTLY SOUTH OF OUR AREA.
THUS...EVEN WITH A WELL DEFINED VORT MAX LIFTING UP ACROSS THE AREA
THIS AFTERNOON AND EARLY EVENING...MOST OF THE ORGANIZED CONVECTION
WITH THIS FEATURE WILL REMAIN OVER THE SOUTHERN AND CENTRAL
MOUNTAINS. ELSEWHERE...ONLY SCATTERED AFTERNOON CONVECTION CAN BE
EXPECTED. THERE ARE A LOT OF CLOUDS WITH THIS VORT SO THAT
CONVECTION MAY BE FURTHER LIMITED IN SCOPE AND INTENSITY THIS
AFTERNOON AND EVENING. STRONGLY WENT WITH THE HRRR MODEL THROUGH
THIS EVENING.

IN ANY CASE...THE VORT QUICKLY EXITS INTO VIRGINIA THIS EVENING...AND
WITH LOSS OF HEATING...ANY CONVECTION WILL QUICKLY DIE DOWN.
STILL...WILL LEAVE MIN POPS OVERNIGHT FOR NOCTURNAL POTENTIAL IN THE
MOIST ATMOSPHERE.

FOR MONDAY...A COLD FRONT WILL APPROACH FROM THE WEST...BUT WILL NOT
REACH OUR AREA UNTIL JUST AFTER THIS PERIOD. SO AGAIN...CONVECTION
WILL BE DEPENDENT ON FEATURES AHEAD OF THE MAIN SHORT WAVE
SUPPORTING THE FRONT. WILL KEEP THE BEST POPS AGAIN...SIMILAR TO
TODAY...IN THE SOUTH AND EAST IN THE AFTERNOON AS THE ONGOING
CONVECTIVE SURFACE BOUNDARY STRUGGLES TO LIFT NORTHWARD. AND
AGAIN...CLOUDS WILL BE A BIG FACTOR TO POTENTIALLY CURB CONVECTION.

FOR TEMPS...TOOK A BLEND OF THE MODELS...WHICH HAS BEEN THE BEST WAY
SO FAR.


&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
UPPER LEVEL S/W TROUGH PUSHES SFC COLD FRONT THROUGH THE AREA MON NT
INTO TUE.  LEAD S/W TROUGH AHEAD OF THE MAIN TROUGH AXIS IS EXODUS
BY THE START OF THE SHORT TERM.  WHAT REMAINS IS A BROAD BASED
TROUGH WITH UPPER LEVEL SUPPORT NOT VERY FOCUSED...OTHER THAN UPPER
LEVEL DIVERGENCE ASSOCIATED WITH RR ENTRANCE REGION OF JET.
INTEGRATED MOISTURE CONTENT ALSO DECREASES FROM THE N...WITH PW
VALUES PEAKING AROUND 1.7 INCHES.  THIS IS STILL ENOUGH TO SUPPORT
DOWNPOURS WITH LOCALLY EXCESSIVE RAINFALL...ESPECIALLY OVER AREAS
THAT GET HIT HARD IN THE NEAR TERM.  FFG VALUES OVER NORTHERN WV
HAVE INCREASED A BIT...BUT POCKETS AS LOW AS 1.2 IN PER HR REMAIN.

ON THE OTHER HAND...THE TIMING OF WHATEVER UPPER LEVEL FORCING THERE
IS ASSOCIATED WITH THE APPROACHING SFC FRONT HAS SLOWED...AND IS
NOW CONDUCIVE TO THE DIURNAL HEATING CONTRIBUTION.

THE SFC FRONT MOVES THROUGH THE AREA MON NT INTO TUE.  THE NAM IS
SLOWER COMPARED WITH GLOBAL MODELS...APPLY REFLECTION THE LOCAL
EFFECTS THE MOUNTAINS HAVE ON SLOWING FRONTS...ESPECIALLY THOSE OF
THE WEAKER SUMMER VARIETY.  THIS LEAVES UNSTABLE AIR IN PLACE AT
LEAST E OF THE OHIO RIVER TUE.  HOWEVER...LITTLE FORCING
REMAINS...SO JUST HAVE SLIGHT CHANCE FOR SHOWERS ENDING TUE
MORNING.  THERE WILL LIKELY BE A LOT OF CU AROUND THROUGH.

TUE NT TURNS OUT CLEAR WITH DENSE VALLEY FOG FORMING...AS HIGH
PRESSURE MOVES INTO THE AREA FROM THE NW.

RAISED TEMPERATURES SLIGHTLY MON AND TUE...MOSTLY VIA THE
MET...STILL AT THE LOW END OF GUIDANCE FOR HIGHS TUE.  FRONT TUE
WILL NOT BE FAST ENOUGH FOR STRATUS TO SET UP IN THE MORNING...BUT
THERE WILL LIKELY BE AN EXPANSIVE CU FIELD COME MIDDAY.   FOR THE
START OF THE SHORT WORK WEEK...SIGNIFICANTLY LOWER TEMPERATURES AND
DEW POINTS REPLACE THE MID SUMMER-LIKE AIR MASS IN PLACE THIS LABOR
DAY WEEKEND.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
EXTENDED FORECAST LEANS HEAVILY TOWARDS THE DRY SIDE WITH HIGH
PRESSURE SETTLING INTO THE AREA THROUGH THE END OF THE WEEK.
TEMPERATURES BEGIN SLIGHTLY BELOW NORMAL WEDNESDAY...AND WILL
SLOWLY MODIFY IN DECENT INSOLATION EACH DAY THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WILL NEED TO WATCH THE 500MB FLOW
TRANSITION TO A MORE ZONAL REGIME FOR THE END OF THE
WEEKEND...WHICH WILL BRING THE NEXT CHANCE FOR ORGANIZED
PRECIPITATION.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THROUGH 18Z MONDAY...
SHORT WAVE CROSSES AREA THIS AFTERNOON...WITH MOST OF THE CONVECTION IN
THE MOUNTAINS...SCATTERED AFTERNOON DIURNAL CONVECTION
ELSEWHERE. EXPECT VFR OUTSIDE OF CONVECTION...EXCEPT WILL INCLUDE
PREVAILING MVFR IN CENTRAL AND SOUTHERN MOUNTAINS...ESPECIALLY AT
BKW GIVEN THE SUSTAINED HIGH POPS.

BULK OF CONVECTION WILL DIE DOWN AFTER 03Z...BUT STILL CANNOT
TOTALLY PULL POPS GIVEN THE MAIN SHORT WAVE AND FRONT ARE STILL TO
THE WEST. WILL KEEP ISOLATED. FOG DEVELOPMENT TONIGHT WILL DEPEND ON
THE AMOUNT OF CLEARING AND LOCATION OF PRECIPITATION DURING THE
DAY...BUT THINK MOST SITES WILL SEE ENOUGH STARS TO BRING IN MVFR TO
IFR FOG AFTER 05Z...ESPECIALLY ALONG RIVERS AND IN VALLEYS WHERE IT
RAINS TODAY.

AFTER 12Z...VFR CEILINGS PREVAILING WITH SCATTERED SHOWERS SPREADING
FROM WEST TO EAST.



FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: FOG DEVELOPMENT AND DENSITY TONIGHT MAY VARY
DUE MAINLY TO CLOUD COVER.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    M    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    M    H    H    H    H    H    M    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN CONVECTION THROUGH AT LEAST MONDAY. IFR FOG POSSIBLE
TUESDAY AND WEDNESDAY MORNINGS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...JMV/26
NEAR TERM...JMV
SHORT TERM...TRM
LONG TERM...26
AVIATION...JMV











AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 139 PM EDT SUN SEP 1 2013

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE TODAY...AND A COLD FRONT APPROACHING
MONDAY...CONTINUE THE CHANCE FOR THUNDERSTORMS.  THE PASSAGE OF THE
FRONT BRINGS AN END TO THE THUNDERSTORMS FOR THE SHORT WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE. ADJUSTED POPS WITH SHORT WAVE CROSSING AREA TODAY PER
RADAR...SATELLITE...SURFACE ANALYSIS TREND AND THE HRRR MODEL. LOOKS
LIKE THE HRRR MODEL HAS A VERY GOOD GRASP ON WHAT IS CURRENTLY GOING
ON MESOSCALE WISE PER THE CURRENT TRENDS...WHEREAS OTHER MODELS ARE
ACCOUNTING MORE FOR GENERAL SYNOPTIC SCALE FORCING AND JUST PAINTING
THE ARE WITH QPF. CONVECTION TO OUR SOUTH AND SOUTHWEST...WHICH HAS
KEPT THINGS QUIET AROUND HERE...HAS WEAKENED TO THE POINT WHERE NEW
CONVECTION DEVELOPING OVER SOUTHERN KENTUCKY IS STARTING TO LIFT
NORTHEAST. THIS WILL BRING THE HIGHEST POPS...PER HRRR...INTO THE
MOUNTAINS THROUGH THIS AFTERNOON. ELSEWHERE...LACK OF FOCUSING AND
UNIMPRESSIVE INSTABILITY SUGGESTS THAT EVEN WITH
SUNSHINE...CONVECTION OF A MORE SCATTERED NATURE CAN BE EXPECTED.
THUS...UPDATED TO LIKELY MOUNTAINS AND SCATTERED ELSEWHERE...WITH A
BIT LESS CLOUDS OUTSIDE OF MOUNTAINS. TEMPS STILL LOOK GOOD.

PREVIOUS DISCUSSION...
THE UNSETTLED WEATHER PATTERN CONTINUES...WITH THE MODELS IN DECENT
AGREEMENT IN THE NEAR TERM PERIOD. UPPER LEVEL DISTURBANCE AT 06Z
MOVING INTO WESTERN OHIO...WILL CONTINUE TO PUSH EAST TODAY...WITH
SHOWERS AND THUNDERSTORMS BECOMING LIKELY...PARTICULARLY DURING PEAK
HEATING HOURS. PW VALUES ABOVE NORMAL ACROSS THE CWA...GENERALLY 1.7
TO 1.9 INCHES FOR THE PERIOD...WITH ANY STORMS PRODUCING HEAVY
DOWNPOURS. COLD FRONT JUST TO THE NORTH OF THE CWA AT 06Z WILL
SLOWLY CONTINUE TO SAG SOUTH INTO SOUTHEAST OHIO ZONES BY THE END OF
THE NEAR TERM AND WEAKEN AS IT DOES SO. THIS WILL THEN BE OVERTAKEN
BY ANOTHER SE MOVING COLD FRONT ON MONDAY AS LOW PRESSURE CONTINUES
TO PUSH TO THE EAST. THERE COULD BE SOME STORMS ON THE STRONGER SIDE
TO THE WEST OF THE CWA OUT AHEAD OF THIS COLD FRONT...AND THE
POTENTIAL EXISTS FOR A STRONGER STORM TO SURVIVE INTO OUR WESTERN
ZONES TODAY...WITH STRONG WIND GUSTS THE PRIMARY THREAT.

SOME PARTIAL CLEARING IS POSSIBLE TONIGHT...MAINLY ACROSS SOUTHEAST
OHIO ZONES...AS THE UPPER DISTURBANCE PUSHES EAST OF THE AREA. FOG
DEVELOPMENT TONIGHT WILL BE TRICKY AND WILL DEPEND LARGELY ON
LOCATIONS OF CONVECTION ACROSS THE CWA...AS WELL AS LOCATION/EXTENT
OF CLEARING. POPS WILL RAPIDLY INCREASE TOWARDS THE END OF THE
PERIOD...AS THE COLD FRONT STARTS TO MOVE SOUTHEAST INTO THE REGION.

WILL CONTINUE TO HOLD OFF ON A FFA ACROSS NORTHERN WV ZONES AND KEEP
A MENTION IN THE HWO...AS AREA HAS SEEN RATHER DRY WEATHER THE PAST
FEW DAYS. 3 HOUR FFG VALUES HAVE RECOVERED NICELY...CLIMBING TO
AROUND 2 INCHES FOR MUCH OF NORTHERN/CENTRAL WV.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
UPPER LEVEL S/W TROUGH PUSHES SFC COLD FRONT THROUGH THE AREA MON NT
INTO TUE.  LEAD S/W TROUGH AHEAD OF THE MAIN TROUGH AXIS IS EXODUS
BY THE START OF THE SHORT TERM.  WHAT REMAINS IS A BROAD BASED
TROUGH WITH UPPER LEVEL SUPPORT NOT VERY FOCUSED...OTHER THAN UPPER
LEVEL DIVERGENCE ASSOCIATED WITH RR ENTRANCE REGION OF JET.
INTEGRATED MOISTURE CONTENT ALSO DECREASES FROM THE N...WITH PW
VALUES PEAKING AROUND 1.7 INCHES.  THIS IS STILL ENOUGH TO SUPPORT
DOWNPOURS WITH LOCALLY EXCESSIVE RAINFALL...ESPECIALLY OVER AREAS
THAT GET HIT HARD IN THE NEAR TERM.  FFG VALUES OVER NORTHERN WV
HAVE INCREASED A BIT...BUT POCKETS AS LOW AS 1.2 IN PER HR REMAIN.

ON THE OTHER HAND...THE TIMING OF WHATEVER UPPER LEVEL FORCING THERE
IS ASSOCIATED WITH THE APPROACHING SFC FRONT HAS SLOWED...AND IS
NOW CONDUCIVE TO THE DIURNAL HEATING CONTRIBUTION.

THE SFC FRONT MOVES THROUGH THE AREA MON NT INTO TUE.  THE NAM IS
SLOWER COMPARED WITH GLOBAL MODELS...APPLY REFLECTION THE LOCAL
EFFECTS THE MOUNTAINS HAVE ON SLOWING FRONTS...ESPECIALLY THOSE OF
THE WEAKER SUMMER VARIETY.  THIS LEAVES UNSTABLE AIR IN PLACE AT
LEAST E OF THE OHIO RIVER TUE.  HOWEVER...LITTLE FORCING
REMAINS...SO JUST HAVE SLIGHT CHANCE FOR SHOWERS ENDING TUE
MORNING.  THERE WILL LIKELY BE A LOT OF CU AROUND THROUGH.

TUE NT TURNS OUT CLEAR WITH DENSE VALLEY FOG FORMING...AS HIGH
PRESSURE MOVES INTO THE AREA FROM THE NW.

RAISED TEMPERATURES SLIGHTLY MON AND TUE...MOSTLY VIA THE
MET...STILL AT THE LOW END OF GUIDANCE FOR HIGHS TUE.  FRONT TUE
WILL NOT BE FAST ENOUGH FOR STRATUS TO SET UP IN THE MORNING...BUT
THERE WILL LIKELY BE AN EXPANSIVE CU FIELD COME MIDDAY.   FOR THE
START OF THE SHORT WORK WEEK...SIGNIFICANTLY LOWER TEMPERATURES AND
DEW POINTS REPLACE THE MID SUMMER-LIKE AIR MASS IN PLACE THIS LABOR
DAY WEEKEND.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
EXTENDED FORECAST LEANS HEAVILY TOWARDS THE DRY SIDE WITH HIGH
PRESSURE SETTLING INTO THE AREA THROUGH THE END OF THE WEEK.
TEMPERATURES BEGIN SLIGHTLY BELOW NORMAL WEDNESDAY...AND WILL
SLOWLY MODIFY IN DECENT INSOLATION EACH DAY THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WILL NEED TO WATCH THE 500MB FLOW
TRANSITION TO A MORE ZONAL REGIME FOR THE END OF THE
WEEKEND...WHICH WILL BRING THE NEXT CHANCE FOR ORGANIZED
PRECIPITATION.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
18Z SUNDAY THROUGH 18Z MONDAY...
SHORT WAVE CROSSES AREA THIS AFTERNOON...WITH MOST OF THE CONVECTION IN
THE MOUNTAINS...SCATTERED AFTERNOON DIURNAL CONVECTION
ELSEWHERE. EXPECT VFR OUTSIDE OF CONVECTION...EXCEPT WILL INCLUDE
PREVAILING MVFR IN CENTRAL AND SOUTHERN MOUNTAINS...ESPECIALLY AT
BKW GIVEN THE SUSTAINED HIGH POPS.

BULK OF CONVECTION WILL DIE DOWN AFTER 03Z...BUT STILL CANNOT
TOTALLY PULL POPS GIVEN THE MAIN SHORT WAVE AND FRONT ARE STILL TO
THE WEST. WILL KEEP ISOLATED. FOG DEVELOPMENT TONIGHT WILL DEPEND ON
THE AMOUNT OF CLEARING AND LOCATION OF PRECIPITATION DURING THE
DAY...BUT THINK MOST SITES WILL SEE ENOUGH STARS TO BRING IN MVFR TO
IFR FOG AFTER 05Z...ESPECIALLY ALONG RIVERS AND IN VALLEYS WHERE IT
RAINS TODAY.

AFTER 12Z...VFR CEILINGS PREVAILING WITH SCATTERED SHOWERS SPREADING
FROM WEST TO EAST.



FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: FOG DEVELOPMENT AND DENSITY TONIGHT MAY VARY
DUE MAINLY TO CLOUD COVER.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    M    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    M    H    H    H    H    H    M    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 18Z MONDAY...
IFR POSSIBLE IN CONVECTION THROUGH AT LEAST MONDAY. IFR FOG POSSIBLE
TUESDAY AND WEDNESDAY MORNINGS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...JMV/SL
SHORT TERM...TRM
LONG TERM...26
AVIATION...JMV











AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 1020 AM EDT SUN SEP 1 2013

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE TODAY...AND A COLD FRONT APPROACHING
MONDAY...CONTINUE THE CHANCE FOR THUNDERSTORMS.  THE PASSAGE OF THE
FRONT BRINGS AN END TO THE THUNDERSTORMS FOR THE SHORT WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE. ADJUSTED POPS WITH SHORT WAVE CROSSING AREA TODAY PER
RADAR...SATELLITE...SURFACE ANALYSIS TREND AND THE HRRR MODEL. LOOKS
LIKE THE HRRR MODEL HAS A VERY GOOD GRASP ON WHAT IS CURRENTLY GOING
ON MESOSCALE WISE PER THE CURRENT TRENDS...WHEREAS OTHER MODELS ARE
ACCOUNTING MORE FOR GENERAL SYNOPTIC SCALE FORCING AND JUST PAINTING
THE ARE WITH QPF. CONVECTION TO OUR SOUTH AND SOUTHWEST...WHICH HAS
KEPT THINGS QUIET AROUND HERE...HAS WEAKENED TO THE POINT WHERE NEW
CONVECTION DEVELOPING OVER SOUTHERN KENTUCKY IS STARTING TO LIFT
NORTHEAST. THIS WILL BRING THE HIGHEST POPS...PER HRRR...INTO THE
MOUNTAINS THROUGH THIS AFTERNOON. ELSEWHERE...LACK OF FOCUSING AND
UNIMPRESSIVE INSTABILITY SUGGESTS THAT EVEN WITH
SUNSHINE...CONVECTION OF A MORE SCATTERED NATURE CAN BE EXPECTED.
THUS...UPDATED TO LIKELY MOUNTAINS AND SCATTERED ELSEWHERE...WITH A
BIT LESS CLOUDS OUTSIDE OF MOUNTAINS. TEMPS STILL LOOK GOOD.

PREVIOUS DISCUSSION...
THE UNSETTLED WEATHER PATTERN CONTINUES...WITH THE MODELS IN DECENT
AGREEMENT IN THE NEAR TERM PERIOD. UPPER LEVEL DISTURBANCE AT 06Z
MOVING INTO WESTERN OHIO...WILL CONTINUE TO PUSH EAST TODAY...WITH
SHOWERS AND THUNDERSTORMS BECOMING LIKELY...PARTICULARLY DURING PEAK
HEATING HOURS. PW VALUES ABOVE NORMAL ACROSS THE CWA...GENERALLY 1.7
TO 1.9 INCHES FOR THE PERIOD...WITH ANY STORMS PRODUCING HEAVY
DOWNPOURS. COLD FRONT JUST TO THE NORTH OF THE CWA AT 06Z WILL
SLOWLY CONTINUE TO SAG SOUTH INTO SOUTHEAST OHIO ZONES BY THE END OF
THE NEAR TERM AND WEAKEN AS IT DOES SO. THIS WILL THEN BE OVERTAKEN
BY ANOTHER SE MOVING COLD FRONT ON MONDAY AS LOW PRESSURE CONTINUES
TO PUSH TO THE EAST. THERE COULD BE SOME STORMS ON THE STRONGER SIDE
TO THE WEST OF THE CWA OUT AHEAD OF THIS COLD FRONT...AND THE
POTENTIAL EXISTS FOR A STRONGER STORM TO SURVIVE INTO OUR WESTERN
ZONES TODAY...WITH STRONG WIND GUSTS THE PRIMARY THREAT.

SOME PARTIAL CLEARING IS POSSIBLE TONIGHT...MAINLY ACROSS SOUTHEAST
OHIO ZONES...AS THE UPPER DISTURBANCE PUSHES EAST OF THE AREA. FOG
DEVELOPMENT TONIGHT WILL BE TRICKY AND WILL DEPEND LARGELY ON
LOCATIONS OF CONVECTION ACROSS THE CWA...AS WELL AS LOCATION/EXTENT
OF CLEARING. POPS WILL RAPIDLY INCREASE TOWARDS THE END OF THE
PERIOD...AS THE COLD FRONT STARTS TO MOVE SOUTHEAST INTO THE REGION.

WILL CONTINUE TO HOLD OFF ON A FFA ACROSS NORTHERN WV ZONES AND KEEP
A MENTION IN THE HWO...AS AREA HAS SEEN RATHER DRY WEATHER THE PAST
FEW DAYS. 3 HOUR FFG VALUES HAVE RECOVERED NICELY...CLIMBING TO
AROUND 2 INCHES FOR MUCH OF NORTHERN/CENTRAL WV.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
UPPER LEVEL S/W TROUGH PUSHES SFC COLD FRONT THROUGH THE AREA MON NT
INTO TUE.  LEAD S/W TROUGH AHEAD OF THE MAIN TROUGH AXIS IS EXODUS
BY THE START OF THE SHORT TERM.  WHAT REMAINS IS A BROAD BASED
TROUGH WITH UPPER LEVEL SUPPORT NOT VERY FOCUSED...OTHER THAN UPPER
LEVEL DIVERGENCE ASSOCIATED WITH RR ENTRANCE REGION OF JET.
INTEGRATED MOISTURE CONTENT ALSO DECREASES FROM THE N...WITH PW
VALUES PEAKING AROUND 1.7 INCHES.  THIS IS STILL ENOUGH TO SUPPORT
DOWNPOURS WITH LOCALLY EXCESSIVE RAINFALL...ESPECIALLY OVER AREAS
THAT GET HIT HARD IN THE NEAR TERM.  FFG VALUES OVER NORTHERN WV
HAVE INCREASED A BIT...BUT POCKETS AS LOW AS 1.2 IN PER HR REMAIN.

ON THE OTHER HAND...THE TIMING OF WHATEVER UPPER LEVEL FORCING THERE
IS ASSOCIATED WITH THE APPROACHING SFC FRONT HAS SLOWED...AND IS
NOW CONDUCIVE TO THE DIURNAL HEATING CONTRIBUTION.

THE SFC FRONT MOVES THROUGH THE AREA MON NT INTO TUE.  THE NAM IS
SLOWER COMPARED WITH GLOBAL MODELS...APPLY REFLECTION THE LOCAL
EFFECTS THE MOUNTAINS HAVE ON SLOWING FRONTS...ESPECIALLY THOSE OF
THE WEAKER SUMMER VARIETY.  THIS LEAVES UNSTABLE AIR IN PLACE AT
LEAST E OF THE OHIO RIVER TUE.  HOWEVER...LITTLE FORCING
REMAINS...SO JUST HAVE SLIGHT CHANCE FOR SHOWERS ENDING TUE
MORNING.  THERE WILL LIKELY BE A LOT OF CU AROUND THROUGH.

TUE NT TURNS OUT CLEAR WITH DENSE VALLEY FOG FORMING...AS HIGH
PRESSURE MOVES INTO THE AREA FROM THE NW.

RAISED TEMPERATURES SLIGHTLY MON AND TUE...MOSTLY VIA THE
MET...STILL AT THE LOW END OF GUIDANCE FOR HIGHS TUE.  FRONT TUE
WILL NOT BE FAST ENOUGH FOR STRATUS TO SET UP IN THE MORNING...BUT
THERE WILL LIKELY BE AN EXPANSIVE CU FIELD COME MIDDAY.   FOR THE
START OF THE SHORT WORK WEEK...SIGNIFICANTLY LOWER TEMPERATURES AND
DEW POINTS REPLACE THE MID SUMMER-LIKE AIR MASS IN PLACE THIS LABOR
DAY WEEKEND.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
EXTENDED FORECAST LEANS HEAVILY TOWARDS THE DRY SIDE WITH HIGH
PRESSURE SETTLING INTO THE AREA THROUGH THE END OF THE WEEK.
TEMPERATURES BEGIN SLIGHTLY BELOW NORMAL WEDNESDAY...AND WILL
SLOWLY MODIFY IN DECENT INSOLATION EACH DAY THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WILL NEED TO WATCH THE 500MB FLOW
TRANSITION TO A MORE ZONAL REGIME FOR THE END OF THE
WEEKEND...WHICH WILL BRING THE NEXT CHANCE FOR ORGANIZED
PRECIPITATION.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
14Z SUNDAY THROUGH 12Z MONDAY...
SHORT WAVE CROSSES AREA TODAY...WITH MOST OF THE CONVECTION IN THE
MOUNTAINS THIS AFTERNOON...SCATTERED AFTERNOON DIURNAL CONVECTION
ELSEWHERE. EXPECT VFR OUTSIDE OF CONVECTION...EXCEPT WILL INCLUDE
PREVAILING MVFR IN CENTRAL AND SOUTHERN MOUNTAINS...ESPECIALLY AT BKW
GIVEN THE SUSTAINED HIGH POPS.

BULK OF CONVECTION WILL DIE DOWN AFTER 03Z...BUT STILL CANNOT
TOTALLY PULL POPS GIVEN THE MAIN SHORT WAVE AND FRONT ARE STILL TO
THE WEST. WILL KEEP ISOLATED. FOG DEVELOPMENT TONIGHT WILL DEPEND ON
THE AMOUNT OF CLEARING AND LOCATION OF PRECIPITATION DURING THE
DAY...BUT THINK MOST SITES WILL SEE ENOUGH STARS TO BRING IN MVFR TO
IFR FOG AFTER 05Z...ESPECIALLY ALONG RIVERS AND IN VALLEYS WHERE IT
RAINS TODAY.



FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND RESTRICTIONS IN CONVECTION DEPENDS
ON HARD TO DISCERN MESOSCALE INFLUENCES. FOG DEVELOPMENT AND DENSITY MAY
VARY FROM CURRENT 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.

UTC 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
EDT 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
CRW CONSISTENCY  H    H    H    H    M    M    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    M    M    M    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    M    M    M    M    M    H    H    H
EKN CONSISTENCY  H    H    H    H    M    M    M    M    H    H    H    H
PKB CONSISTENCY  H    H    H    M    M    M    M    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    M    M    M    M    M    H    H    H

AFTER 12Z MONDAY...
IFR POSSIBLE IN CONVECTION THROUGH AT LEAST MONDAY. IFR FOG POSSIBLE
TUESDAY AND WEDNESDAY MORNINGS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...JMV/SL
SHORT TERM...TRM
LONG TERM...26
AVIATION...JMV/SL











AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 624 AM EDT SUN SEP 1 2013

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE TODAY...AND A COLD FRONT APPROACHING
MONDAY...CONTINUE THE CHANCE FOR THUNDERSTORMS.  THE PASSAGE OF THE
FRONT BRINGS AN END TO THE THUNDERSTORMS FOR THE SHORT WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE UNSETTLED WEATHER PATTERN CONTINUES...WITH THE MODELS IN DECENT
AGREEMENT IN THE NEAR TERM PERIOD. UPPER LEVEL DISTURBANCE AT 06Z
MOVING INTO WESTERN OHIO...WILL CONTINUE TO PUSH EAST TODAY...WITH
SHOWERS AND THUNDERSTORMS BECOMING LIKELY...PARTICULARLY DURING PEAK
HEATING HOURS. PW VALUES ABOVE NORMAL ACROSS THE CWA...GENERALLY 1.7
TO 1.9 INCHES FOR THE PERIOD...WITH ANY STORMS PRODUCING HEAVY
DOWNPOURS. COLD FRONT JUST TO THE NORTH OF THE CWA AT 06Z WILL
SLOWLY CONTINUE TO SAG SOUTH INTO SOUTHEAST OHIO ZONES BY THE END OF
THE NEAR TERM AND WEAKEN AS IT DOES SO. THIS WILL THEN BE OVERTAKEN
BY ANOTHER SE MOVING COLD FRONT ON MONDAY AS LOW PRESSURE CONTINUES
TO PUSH TO THE EAST. THERE COULD BE SOME STORMS ON THE STRONGER SIDE
TO THE WEST OF THE CWA OUT AHEAD OF THIS COLD FRONT...AND THE
POTENTIAL EXISTS FOR A STRONGER STORM TO SURVIVE INTO OUR WESTERN
ZONES TODAY...WITH STRONG WIND GUSTS THE PRIMARY THREAT.

SOME PARTIAL CLEARING IS POSSIBLE TONIGHT...MAINLY ACROSS SOUTHEAST
OHIO ZONES...AS THE UPPER DISTURBANCE PUSHES EAST OF THE AREA. FOG
DEVELOPMENT TONIGHT WILL BE TRICKY AND WILL DEPEND LARGELY ON
LOCATIONS OF CONVECTION ACROSS THE CWA...AS WELL AS LOCATION/EXTENT
OF CLEARING. POPS WILL RAPIDLY INCREASE TOWARDS THE END OF THE
PERIOD...AS THE COLD FRONT STARTS TO MOVE SOUTHEAST INTO THE REGION.

WILL CONTINUE TO HOLD OFF ON A FFA ACROSS NORTHERN WV ZONES AND KEEP
A MENTION IN THE HWO...AS AREA HAS SEEN RATHER DRY WEATHER THE PAST
FEW DAYS. 3 HOUR FFG VALUES HAVE RECOVERED NICELY...CLIMBING TO
AROUND 2 INCHES FOR MUCH OF NORTHERN/CENTRAL WV.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
UPPER LEVEL S/W TROUGH PUSHES SFC COLD FRONT THROUGH THE AREA MON NT
INTO TUE.  LEAD S/W TROUGH AHEAD OF THE MAIN TROUGH AXIS IS EXODUS
BY THE START OF THE SHORT TERM.  WHAT REMAINS IS A BROAD BASED
TROUGH WITH UPPER LEVEL SUPPORT NOT VERY FOCUSED...OTHER THAN UPPER
LEVEL DIVERGENCE ASSOCIATED WITH RR ENTRANCE REGION OF JET.
INTEGRATED MOISTURE CONTENT ALSO DECREASES FROM THE N...WITH PW
VALUES PEAKING AROUND 1.7 INCHES.  THIS IS STILL ENOUGH TO SUPPORT
DOWNPOURS WITH LOCALLY EXCESSIVE RAINFALL...ESPECIALLY OVER AREAS
THAT GET HIT HARD IN THE NEAR TERM.  FFG VALUES OVER NORTHERN WV
HAVE INCREASED A BIT...BUT POCKETS AS LOW AS 1.2 IN PER HR REMAIN.

ON THE OTHER HAND...THE TIMING OF WHATEVER UPPER LEVEL FORCING THERE
IS ASSOCIATED WITH THE APPROACHING SFC FRONT HAS SLOWED...AND IS
NOW CONDUCIVE TO THE DIURNAL HEATING CONTRIBUTION.

THE SFC FRONT MOVES THROUGH THE AREA MON NT INTO TUE.  THE NAM IS
SLOWER COMPARED WITH GLOBAL MODELS...APPLY REFLECTION THE LOCAL
EFFECTS THE MOUNTAINS HAVE ON SLOWING FRONTS...ESPECIALLY THOSE OF
THE WEAKER SUMMER VARIETY.  THIS LEAVES UNSTABLE AIR IN PLACE AT
LEAST E OF THE OHIO RIVER TUE.  HOWEVER...LITTLE FORCING
REMAINS...SO JUST HAVE SLIGHT CHANCE FOR SHOWERS ENDING TUE
MORNING.  THERE WILL LIKELY BE A LOT OF CU AROUND THROUGH.

TUE NT TURNS OUT CLEAR WITH DENSE VALLEY FOG FORMING...AS HIGH
PRESSURE MOVES INTO THE AREA FROM THE NW.

RAISED TEMPERATURES SLIGHTLY MON AND TUE...MOSTLY VIA THE
MET...STILL AT THE LOW END OF GUIDANCE FOR HIGHS TUE.  FRONT TUE
WILL NOT BE FAST ENOUGH FOR STRATUS TO SET UP IN THE MORNING...BUT
THERE WILL LIKELY BE AN EXPANSIVE CU FIELD COME MIDDAY.   FOR THE
START OF THE SHORT WORK WEEK...SIGNIFICANTLY LOWER TEMPERATURES AND
DEW POINTS REPLACE THE MID SUMMER-LIKE AIR MASS IN PLACE THIS LABOR
DAY WEEKEND.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
EXTENDED FORECAST LEANS HEAVILY TOWARDS THE DRY SIDE WITH HIGH
PRESSURE SETTLING INTO THE AREA THROUGH THE END OF THE WEEK.
TEMPERATURES BEGIN SLIGHTLY BELOW NORMAL WEDNESDAY...AND WILL
SLOWLY MODIFY IN DECENT INSOLATION EACH DAY THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WILL NEED TO WATCH THE 500MB FLOW
TRANSITION TO A MORE ZONAL REGIME FOR THE END OF THE
WEEKEND...WHICH WILL BRING THE NEXT CHANCE FOR ORGANIZED
PRECIPITATION.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
12Z SUNDAY THROUGH 12Z MONDAY...

PATCHY MVFR/IFR FOG AT A FEW LOCATIONS...BUT FOR THE MOST
PART...VFR CONDITIONS WITH LIGHT SURFACE WINDS.

CONVECTION WILL INCREASE IN COVERAGE AGAIN AFTER 15Z...AS AN UPPER
DISTURBANCE MOVES EAST THROUGH THE AREA. EXPECT BRIEF MVFR/IFR
CONDITIONS AND GUSTY WINDS IN VICINITY OF STORMS. BULK OF
CONVECTION WILL DIE DOWN AFTER 03Z. FOG DEVELOPMENT TONIGHT WILL
DEPEND ON THE AMOUNT OF CLEARING AND LOCATION OF PRECIPITATION
DURING THE DAY. BEST LOCATION FOR POTENTIAL FOG DEVELOPMENT WILL
BE EASTERN KENTUCKY AND SOUTHEAST OHIO WHERE BETTER CLEARING IS
EXPECTED...BUT THINKING MOST LOCATIONS WILL REMAIN VFR UNDER
EXTENSIVE CLOUD COVER.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND RESTRICTIONS IN CONVECTION DEPENDS
ON HARD TO DISCERN MESOSCALE INFLUENCES. FOG DEVELOPMENT AND DENSITY MAY
VARY FROM CURRENT 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.

UTC 1HRLY       11   12   13   14   15   16   17   18   19   20   21   22
EDT 1HRLY       07   08   09   10   11   12   13   14   15   16   17   18
CRW CONSISTENCY  H    H    H    H    H    H    H    M    M    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    M    M    M    H    H    H
BKW CONSISTENCY  M    H    H    H    H    H    H    M    M    M    M    M
EKN CONSISTENCY  M    H    H    H    H    H    H    M    M    M    M    H
PKB CONSISTENCY  H    H    H    H    H    H    M    M    M    M    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    M    M    M    M    M

AFTER 12Z MONDAY...
IFR POSSIBLE IN CONVECTION THROUGH AT LEAST MONDAY. IFR FOG POSSIBLE
TUESDAY AND WEDNESDAY MORNINGS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...SL
SHORT TERM...TRM
LONG TERM...26
AVIATION...SL









AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 401 AM EDT SUN SEP 1 2013

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE TODAY...AND A COLD FRONT APPROACHING
MONDAY...CONTINUE THE CHANCE FOR THUNDERSTORMS.  THE PASSAGE OF THE
FRONT BRINGS AN END TO THE THUNDERSTORMS FOR THE SHORT WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE UNSETTLED WEATHER PATTERN CONTINUES...WITH THE MODELS IN DECENT
AGREEMENT IN THE NEAR TERM PERIOD. UPPER LEVEL DISTURBANCE AT 06Z
MOVING INTO WESTERN OHIO...WILL CONTINUE TO PUSH EAST TODAY...WITH
SHOWERS AND THUNDERSTORMS BECOMING LIKELY...PARTICULARLY DURING PEAK
HEATING HOURS. PW VALUES ABOVE NORMAL ACROSS THE CWA...GENERALLY 1.7
TO 1.9 INCHES FOR THE PERIOD...WITH ANY STORMS PRODUCING HEAVY
DOWNPOURS. COLD FRONT JUST TO THE NORTH OF THE CWA AT 06Z WILL
SLOWLY CONTINUE TO SAG SOUTH INTO SOUTHEAST OHIO ZONES BY THE END OF
THE NEAR TERM AND WEAKEN AS IT DOES SO. THIS WILL THEN BE OVERTAKEN
BY ANOTHER SE MOVING COLD FRONT ON MONDAY AS LOW PRESSURE CONTINUES
TO PUSH TO THE EAST. THERE COULD BE SOME STORMS ON THE STRONGER SIDE
TO THE WEST OF THE CWA OUT AHEAD OF THIS COLD FRONT...AND THE
POTENTIAL EXISTS FOR A STRONGER STORM TO SURVIVE INTO OUR WESTERN
ZONES TODAY...WITH STRONG WIND GUSTS THE PRIMARY THREAT.

SOME PARTIAL CLEARING IS POSSIBLE TONIGHT...MAINLY ACROSS SOUTHEAST
OHIO ZONES...AS THE UPPER DISTURBANCE PUSHES EAST OF THE AREA. FOG
DEVELOPMENT TONIGHT WILL BE TRICKY AND WILL DEPEND LARGELY ON
LOCATIONS OF CONVECTION ACROSS THE CWA...AS WELL AS LOCATION/EXTENT
OF CLEARING. POPS WILL RAPIDLY INCREASE TOWARDS THE END OF THE
PERIOD...AS THE COLD FRONT STARTS TO MOVE SOUTHEAST INTO THE REGION.

WILL CONTINUE TO HOLD OFF ON A FFA ACROSS NORTHERN WV ZONES AND KEEP
A MENTION IN THE HWO...AS AREA HAS SEEN RATHER DRY WEATHER THE PAST
FEW DAYS. 3 HOUR FFG VALUES HAVE RECOVERED NICELY...CLIMBING TO
AROUND 2 INCHES FOR MUCH OF NORTHERN/CENTRAL WV.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
UPPER LEVEL S/W TROUGH PUSHES SFC COLD FRONT THROUGH THE AREA MON NT
INTO TUE.  LEAD S/W TROUGH AHEAD OF THE MAIN TROUGH AXIS IS EXODUS
BY THE START OF THE SHORT TERM.  WHAT REMAINS IS A BROAD BASED
TROUGH WITH UPPER LEVEL SUPPORT NOT VERY FOCUSED...OTHER THAN UPPER
LEVEL DIVERGENCE ASSOCIATED WITH RR ENTRANCE REGION OF JET.
INTEGRATED MOISTURE CONTENT ALSO DECREASES FROM THE N...WITH PW
VALUES PEAKING AROUND 1.7 INCHES.  THIS IS STILL ENOUGH TO SUPPORT
DOWNPOURS WITH LOCALLY EXCESSIVE RAINFALL...ESPECIALLY OVER AREAS
THAT GET HIT HARD IN THE NEAR TERM.  FFG VALUES OVER NORTHERN WV
HAVE INCREASED A BIT...BUT POCKETS AS LOW AS 1.2 IN PER HR REMAIN.

ON THE OTHER HAND...THE TIMING OF WHATEVER UPPER LEVEL FORCING THERE
IS ASSOCIATED WITH THE APPROACHING SFC FRONT HAS SLOWED...AND IS
NOW CONDUCIVE TO THE DIURNAL HEATING CONTRIBUTION.

THE SFC FRONT MOVES THROUGH THE AREA MON NT INTO TUE.  THE NAM IS
SLOWER COMPARED WITH GLOBAL MODELS...APPLY REFLECTION THE LOCAL
EFFECTS THE MOUNTAINS HAVE ON SLOWING FRONTS...ESPECIALLY THOSE OF
THE WEAKER SUMMER VARIETY.  THIS LEAVES UNSTABLE AIR IN PLACE AT
LEAST E OF THE OHIO RIVER TUE.  HOWEVER...LITTLE FORCING
REMAINS...SO JUST HAVE SLIGHT CHANCE FOR SHOWERS ENDING TUE
MORNING.  THERE WILL LIKELY BE A LOT OF CU AROUND THROUGH.

TUE NT TURNS OUT CLEAR WITH DENSE VALLEY FOG FORMING...AS HIGH
PRESSURE MOVES INTO THE AREA FROM THE NW.

RAISED TEMPERATURES SLIGHTLY MON AND TUE...MOSTLY VIA THE
MET...STILL AT THE LOW END OF GUIDANCE FOR HIGHS TUE.  FRONT TUE
WILL NOT BE FAST ENOUGH FOR STRATUS TO SET UP IN THE MORNING...BUT
THERE WILL LIKELY BE AN EXPANSIVE CU FIELD COME MIDDAY.   FOR THE
START OF THE SHORT WORK WEEK...SIGNIFICANTLY LOWER TEMPERATURES AND
DEW POINTS REPLACE THE MID SUMMER-LIKE AIR MASS IN PLACE THIS LABOR
DAY WEEKEND.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
EXTENDED FORECAST LEANS HEAVILY TOWARDS THE DRY SIDE WITH HIGH
PRESSURE SETTLING INTO THE AREA THROUGH THE END OF THE WEEK.
TEMPERATURES BEGIN SLIGHTLY BELOW NORMAL WEDNESDAY...AND WILL
SLOWLY MODIFY IN DECENT INSOLATION EACH DAY THROUGH THE END OF THE
WEEK AND INTO THE WEEKEND. WILL NEED TO WATCH THE 500MB FLOW
TRANSITION TO A MORE ZONAL REGIME FOR THE END OF THE
WEEKEND...WHICH WILL BRING THE NEXT CHANCE FOR ORGANIZED
PRECIPITATION.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
ISOLD SHOWERS/STORMS CONTINUING TO LINGER THROUGH ABOUT 11Z...WITH
BRIEF MVFR/IFR CONDITIONS IN VICINITY. OTHERWISE...PATCHY MVFR/IFR
FOG...BUT MOST AREAS SHOULD REMAIN VFR UNDER EXTENSIVE CLOUD SHIELD.

CONVECTION WILL INCREASE IN COVERAGE AGAIN AFTER 12Z...AS AN UPPER
DISTURBANCE MOVES EAST THROUGH THE AREA. EXPECT BRIEF MVFR/IFR
CONDITIONS AND GUSTY WINDS IN VICINITY OF STORMS. BULK OF
CONVECTION WILL DIE DOWN AFTER 03Z. FOG DEVELOPMENT TONIGHT WILL
DEPEND ON THE AMOUNT OF CLEARING AND LOCATION OF PRECIPITATION
DURING THE DAY. BEST LOCATION FOR POTENTIAL FOG DEVELOPMENT WILL
BE EASTERN KENTUCKY AND SOUTHEAST OHIO WHERE BETTER CLEARING IS
EXPECTED.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING AND POTENTIAL FOR CONVECTION DEPENDS
ON HARD TO DISCERN MESOSCALE INFLUENCES. FOG TIMING AND DENSITY
MAY VARY FROM CURRENT 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                              SUN 09/01/13
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  M    M    L    L    H    H    H    H    H    H    H    H
HTS CONSISTENCY  M    M    L    L    M    H    H    H    H    H    H    M
BKW CONSISTENCY  H    H    H    H    M    H    H    H    H    H    H    H
EKN CONSISTENCY  M    L    L    L    M    M    L    H    H    H    H    H
PKB CONSISTENCY  M    M    L    L    H    H    H    H    H    H    H    M
CKB CONSISTENCY  M    M    L    L    H    H    H    H    H    H    H    H

AFTER 06Z MONDAY...
IFR POSSIBLE IN CONVECTION THROUGH AT LEAST MONDAY. IFR FOG POSSIBLE
TUESDAY AND WEDNESDAY MORNINGS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...TRM/SL
NEAR TERM...SL
SHORT TERM...TRM
LONG TERM...26
AVIATION...SL







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 1050 PM EDT MON SEP 2 2013

.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TONIGHT AND
THEN CROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA LATE ON
TUESDAY. DRY HIGH PRESSURE WILL FILL IN BEHIND THE FRONT ON
WEDNESDAY. HIGH PRESSURE WILL LINGER LATE THIS WEEK INTO THE
WEEKEND...WITH ATLANTIC MOISTURE SLOWLY RETURNING TO THE AREA.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 1045 PM EDT...CONVECTION HAS DEVELOPED OVER THE NC FOOTHILLS.
IT SHOULD CONTINUE TO MOVE EAST...GENERALLY NORTH OF I40 THE NEXT
COUPLE HOURS. SPOTTY HIGH BASED LIGHT RAIN HAS DEVELOPED OVER THE
UPSTATE. LOOKING AT THE COOLING TRENDS ON THE IR IMAGERY...I THINK
THIS IS MID-LEVEL ASCENT WITH AN MCV THAT HAS SLOWLY BEEN MOVING ENE
INTO THE REGION FROM OUT OF GA. I DON/T THINK IT WILL TRIGGER ANY
SURFACE BASED CONVECTION AND I/VE KEPT POPS LOW IN THIS AREA. THE
HRRR AND RUC BRING CONVECTION INTO THE NC MTNS AROUND 8 TO 9 UTC.
THIS MATCHES UP ALMOST PERFECTLY WITH TIMING THE ONGOING TSTMS OVER
SE KY AND MIDDLE TN. THE STORMS MAY FLARE UP FOR A WHILE OVER THE
GREAT VALLEY OF TN...ALLOW FOR A SCATTERED TO BROKEN LINE OF STORMS
TO ENTER THE MTNS AROUND THIS TIME. HOWEVER...THE WEAK LLVL WIND
FIELDS SHOULD NOT SUPPORT CONVECTION TOO FAR EAST OF THE TN LINE.
I/VE UPPED POPS ALONG THE TN LINE LATER TONIGHT TO ACCOUNT FOR THIS.

AS OF 645 PM EDT...NOT MUCH CONVECTION HAS FIRED OVER THE REGION SO
FAR THIS EVENING. I/VE CUT BACK POPS TO ACCOUNT FOR THIS. SOME OF
THE CONVECTION ALLOWING MODELS GENERATE CONVECTION DURING THE COURSE
OF THE EVENING...INCLUDING THE HRRR WHICH BLOWS UP CONVECTION OVER
THE CHARLOTTE AREA...AND THE HIGH RES WRF WHICH BRINGS CONVECTION
INTO THE NC MTNS AFTER MIDNIGHT. WITH THESE SIGNALS I DID NOT REMOVE
POPS ALTOGETHER...THOUGH I DID KEEP THEM IN THE SLIGHT CHANCE TO LOW
END CHANCE RANGE AS THE CHANCES FOR RAIN AT ANY GIVEN LOCATION ARE
LOW.

AS OF 145 PM EDT...STILL ANTICIPATE MID TO LATE AFTN CONVECTION
DEVELOPING INITIALLY ALONG THE BLUE RIDGE...ALTHOUGH THE EARLY DAY
DEBRIS CLOUDS HAVE SLOWED THIS PROCESS A LITTLE. WESTERLY STEERING
FLOW SHOULD THEN TAKE SCT ACTIVITY EWD ACROSS THE FOOTHILLS LATE
THIS AFTN...BUT IT IS QUESTIONABLE HOW MUCH WILL SURVIVE INTO THE
ERN PIEDMONT. WILL STILL MAINTAIN CHC POPS OUT TO INTERSTATE
77...HOWEVER...SINCE SB CAPE VALUES ARE RUNNING 2000 TO 3000 J/KG IN
THAT AREA. ANY OUTFLOW DRIVEN CONVECTION WILL DIMINISH THIS EVENING
WITH LOSS OF DAYTIME HEATING AND WITH THE APPROACHING SFC COLD FRONT
REMAINING W OF THE APPALACHIANS.

FOR THE BIGGER PICTURE...AN UPPER LOW CENTER MOVING EWD FROM ONTARIO
CANADA INTO QUEBEC WILL SHARPEN UP AN ASSOCIATED LONGWAVE TROUGH
AXIS OVER THE ERN U.S. TONIGHT THROUGH TUESDAY. SHORTWAVE FEATURES
OF GREATER VORTICITY WILL BE HARD TO TIME IN THE LONGWAVE...BUT IT
APPEARS THE BEST UPPER SUPPORT WILL CROSS THE WRN CAROLINAS AND NE
GA MAINLY 12Z TO 18Z TUE. HOWEVER...THE SFC COLD FRONT SHOULD TRAIL
THE BETTER UPPER FORCING THROUGH THE DAY. WHILE MID AND UPPER DRYING
OCCURS BEHIND THE DEPARTING WAVE BY MIDDAY...THE SFC COLD FRONT WILL
LIKELY PASS THROUGH THE REGION DURING THE AFTN. WITH BOUNDARY LAYER
MOISTURE BEING SLOWEST TO DRY...ANOTHER ROUND OF SCATTERED
THUNDERSTORMS WILL BE POSSIBLE ALONG THE IMMEDIATE COLD FRONT MAINLY
IN AREAS SE OF INTERSTATE 85 TUE AFTN. STEEP EQUIVALENT POTENTIAL
TEMP LAPSES ACCOMPANYING THE IMMEDIATE FROPA WILL CREATE THE
POSSIBILITY FOR ISOLD WIND DAMAGE WITH ANY TSTMS. WILL CONTINUE TO
LEAN TOWARD THE BIAS CORRECTED GUIDANCE FOR MINS AND MAXES THROUGH
THE PERIOD UNTIL AFTER FROPA.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 110 PM EDT MONDAY...BROAD UPPER TROF WILL PERSIST THROUGH THE
PERIOD.  PASSING FRONTAL BOUNDARY SHOULD BE EXITING THE REGION TO
THE SOUTHEAST BY TUESDAY NIGHT.  IN RESPONSE...POPS WILL TAPER OFF
GRADUALLY DURING THE OVERNIGHT HOURS UNTIL ALL MENTION OF
PRECIPITATION IS REMOVED FROM THE FCST.  DRIER AIR WILL WORK INTO
THE REGION ON WEDNESDAY AS WEAK SURFACE HIGH PRESSURE BUILDS OVER
THE OHIO VALLEY.  EASTERLY FLOW AROUND THE RIDGE WILL PROMOTE A
SLIGHT CHANCE FOR SHOWERS ALONG THE FOOTHILLS OF SOUTHWEST NC DURING
THE AFTERNOON HOURS.  THE REST OF THE REGION SHOULD REMAIN DRY AS THE
AIRMASS REMAINS STABLE.  LATEST GFS/ECMWF GUIDANCE PLACES THE ABOVE
MENTIONED SURFACE RIDGE OFF THE EAST COAST BY THURSDAY MORNING. THIS
ALLOWS THE LOW LEVEL FLOW TO SHIFT TO THE SOUTHEAST PROMOTING
MARGINAL MOISTURE ADVECTION INTO THE PIEDMONT REGIONS OF NC AND SC.
HOWEVER...NAM GUIDANCE KEEPS THE FLOW OUT OF THE WEST NORTHWEST THUS
INHIBITING THE BULK OF THE MOISTURE AXIS FROM PUSHING BACK INTO
REGION.  BLENDED GFS/ECMWF INTO THE PREVIOUS FORECAST WHICH RESULTED
IN SLIGHT CHANCE DIURNAL POPS ACROSS THE REGION.  TEMPERATURES
DURING THE SHORT TERM PERIOD WILL REMAIN JUST A FEW DEGREES BELOW
NORMAL IN THE WAKE OF THE FROPA.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 130 PM EDT MONDAY...REINFORCING COLD FRONT WILL BE LOCATED
OVER THE SOUTHERN OHIO VALLEY BY LATE THURSDAY EVENING WHILE UPPER
LEVEL RIDGE SETTLES IN ACROSS THE CENTRAL PLAINS. STRONG SURFACE
HIGH PRESSURE WILL BUILD IN BEHIND THE ABOVE MENTIONED FRONTAL
BOUNDARY ACROSS THE GREAT LAKES REGION. AS THE BOUNDARY MOVES
THROUGH THE AREA ON FRIDAY...THE SURFACE HIGH OVER THE GREAT LAKES
WILL MIGRATE TO THE SOUTHEAST EVENTUALLY SETTING UP OVER CHESAPEAKE
BAY.  THIS WILL ALLOW FOR LOW LEVEL FLOW TO SHIFT EASTERLY THUS
PROMOTING UPSLOPE FLOW ALONG THE HIGH TERRAIN WHERE CHANCE POPS ARE
HIGHLIGHTED.  ELSEWHERE...SUBSIDENCE FROM THE RIDGE WILL MOST LIKELY
KEEP ANY CONVECTION AT BAY.  WITH THAT SAID...THERE WILL STILL BE
ENOUGH MOISTURE IN THE ATMOSPHERE TO ALLOW FOR SOME CONVECTION IF
THE RIDGE IS WEAKER THAN EXPECTED...ESPECIALLY ON THE WESTERN
PERIPHERY.  THUS MENTIONED SLIGHT CHANCE POPS OUTSIDE OF THE
MOUNTAINS FOR FRIDAY AFTERNOON.

THE SURFACE RIDGE SHIFTS FURTHER TO THE EAST ON SATURDAY ALLOWING
FOR LOW LEVEL FLOW TO VEER MORE SOUTHERLY.  EXPECTING INCREASING
MOISTURE ADVECTION WITH THIS PATTERN FOR SATURDAY AND INTO SUNDAY
WHERE DIURNAL POPS ARE HIGHLIGHTED IN THE FORECAST.  TEMPERATURES
THROUGH THE EXTENDED RANGE PERIOD WILL REMAIN A FEW DEGREES BELOW
NORMAL WITH A GRADUAL WARMING TREND SETTLING IN LATE IN THE
PERIOD.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
AT KCLT...SOME OF THE NUMERICAL MODELS GENERATE CONVECTION OVER THE
NC PIEDMONT OVERNIGHT. THERE ARE A FEW TSTMS DEVELOPING OVER THE
FOOTHILLS ATTM. CONFIDENCE ISN/T NEARLY HIGH ENOUGH TO INCLUDE
THUNDER...BUT WE WILL KEEP A CLOSE EYE ON UPSTREAM TRENDS. HIGH CIGS
WILL CONTINUE OVERNIGHT...BUT WITH ANOTHER ROUND OF MVFR VSBY...AND
POSSIBLY BRIEF IFR CONDITIONS POSSIBLE TOWARD DAYBREAK. WILL
CONTINUE TO DAY SHIFTS FORECAST WITH SOME FEW010 TO INDICATE PATCHY
STRATUS. ANTICIPATE CUMULUS DEVELOPING WITH HEATING JUST AHEAD OF
THE FRONT ON TUE...WITH PROB30 NOW ADVERTISED 18Z TO 22Z. STEADY
LIGHT WSW FLOW WILL FINALLY TURN NW TOWARD THE END OF THE PERIOD.

ELSEWHERE...ISOLD SHRA/TSTMS HAVE DEVELOPED OVER THE SOUTHERN NC
MTNS AND THE UPSTATE WELL WEST OF GREENVILLE. CONVECTION MAY
APPROACH JUST ABOUT ANY SITE FROM KAVL DOWN TO KAND...BUT CHANCES
LOOK LOW. I/LL GO WITH VCSH FOR A FEW HOURS...BUT WILL HOLD OFF ON
ANY MORE AGGRESSIVE WORDING. ANOTHER ROUND OF IFR FOG AND CIGS LOOKS
LIKELY AT THE NC SITES TONIGHT...WITH MAINLY MVFR CONDITIONS
EXPECTED AT THE UPSTATE TAF SITES. CANNOT RULE OUT BRIEF IFR IN SC
AS WELL...BUT WITH LOW CONFIDENCE GIVEN THE POTENTIAL FOR MID AND
HIGH CLOUDS. FORCING WILL IMPROVE TUE MORNING BOTH ALOFT AND ALONG
THE APPROACHING FRONT...BUT INSTABILITY WILL BE THE MAIN QUESTION
FOR ANY TSRA. WILL FEATURE MAINLY VCSH AT THE TAF SITES...EXCEPT
VCTS AT KAND TOWARD MIDDAY.

OUTLOOK...A COLD FRONT WILL CROSS THE AREA LATE TUESDAY. DRIER AIR
WILL FOLLOW THE FRONTAL PASSAGE WED INTO THU...WITH HIGH PRESSURE
LINGERING INTO THE WEEKEND AS ATLANTIC MOISTURE RETURNS SLOWLY.

CONFIDENCE TABLE...

            02-08Z        08-14Z        14-20Z        20-02Z
KCLT       HIGH  95%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH  83%     LOW   59%     MED   60%
KHKY       HIGH  91%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH  95%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...HG
NEAR TERM...HG/MCAVOY
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...MCAVOY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 806 PM EDT MON SEP 2 2013

.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TONIGHT AND
THEN CROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA LATE ON
TUESDAY. DRY HIGH PRESSURE WILL FILL IN BEHIND THE FRONT ON
WEDNESDAY. HIGH PRESSURE WILL LINGER LATE THIS WEEK INTO THE
WEEKEND...WITH ATLANTIC MOISTURE SLOWLY RETURNING TO THE AREA.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 645 PM EDT...NOT MUCH CONVECTION HAS FIRED OVER THE REGION SO
FAR THIS EVENING. I/VE CUT BACK POPS TO ACCOUNT FOR THIS. SOME OF
THE CONVECTION ALLOWING MODELS GENERATE CONVECTION DURING THE COURSE
OF THE EVENING...INCLUDING THE HRRR WHICH BLOWS UP CONVECTION OVER
THE CHARLOTTE AREA...AND THE HIGH RES WRF WHICH BRINGS CONVECTION
INTO THE NC MTNS AFTER MIDNIGHT. WITH THESE SIGNALS I DID NOT REMOVE
POPS ALTOGETHER...THOUGH I DID KEEP THEM IN THE SLIGHT CHANCE TO LOW
END CHANCE RANGE AS THE CHANCES FOR RAIN AT ANY GIVEN LOCATION ARE
LOW.

AS OF 145 PM EDT...STILL ANTICIPATE MID TO LATE AFTN CONVECTION
DEVELOPING INITIALLY ALONG THE BLUE RIDGE...ALTHOUGH THE EARLY DAY
DEBRIS CLOUDS HAVE SLOWED THIS PROCESS A LITTLE. WESTERLY STEERING
FLOW SHOULD THEN TAKE SCT ACTIVITY EWD ACROSS THE FOOTHILLS LATE
THIS AFTN...BUT IT IS QUESTIONABLE HOW MUCH WILL SURVIVE INTO THE
ERN PIEDMONT. WILL STILL MAINTAIN CHC POPS OUT TO INTERSTATE
77...HOWEVER...SINCE SB CAPE VALUES ARE RUNNING 2000 TO 3000 J/KG IN
THAT AREA. ANY OUTFLOW DRIVEN CONVECTION WILL DIMINISH THIS EVENING
WITH LOSS OF DAYTIME HEATING AND WITH THE APPROACHING SFC COLD FRONT
REMAINING W OF THE APPALACHIANS.

FOR THE BIGGER PICTURE...AN UPPER LOW CENTER MOVING EWD FROM ONTARIO
CANADA INTO QUEBEC WILL SHARPEN UP AN ASSOCIATED LONGWAVE TROUGH
AXIS OVER THE ERN U.S. TONIGHT THROUGH TUESDAY. SHORTWAVE FEATURES
OF GREATER VORTICITY WILL BE HARD TO TIME IN THE LONGWAVE...BUT IT
APPEARS THE BEST UPPER SUPPORT WILL CROSS THE WRN CAROLINAS AND NE
GA MAINLY 12Z TO 18Z TUE. HOWEVER...THE SFC COLD FRONT SHOULD TRAIL
THE BETTER UPPER FORCING THROUGH THE DAY. WHILE MID AND UPPER DRYING
OCCURS BEHIND THE DEPARTING WAVE BY MIDDAY...THE SFC COLD FRONT WILL
LIKELY PASS THROUGH THE REGION DURING THE AFTN. WITH BOUNDARY LAYER
MOISTURE BEING SLOWEST TO DRY...ANOTHER ROUND OF SCATTERED
THUNDERSTORMS WILL BE POSSIBLE ALONG THE IMMEDIATE COLD FRONT MAINLY
IN AREAS SE OF INTERSTATE 85 TUE AFTN. STEEP EQUIVALENT POTENTIAL
TEMP LAPSES ACCOMPANYING THE IMMEDIATE FROPA WILL CREATE THE
POSSIBILITY FOR ISOLD WIND DAMAGE WITH ANY TSTMS. WILL CONTINUE TO
LEAN TOWARD THE BIAS CORRECTED GUIDANCE FOR MINS AND MAXES THROUGH
THE PERIOD UNTIL AFTER FROPA.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 110 PM EDT MONDAY...BROAD UPPER TROF WILL PERSIST THROUGH THE
PERIOD.  PASSING FRONTAL BOUNDARY SHOULD BE EXITING THE REGION TO
THE SOUTHEAST BY TUESDAY NIGHT.  IN RESPONSE...POPS WILL TAPER OFF
GRADUALLY DURING THE OVERNIGHT HOURS UNTIL ALL MENTION OF
PRECIPITATION IS REMOVED FROM THE FCST.  DRIER AIR WILL WORK INTO
THE REGION ON WEDNESDAY AS WEAK SURFACE HIGH PRESSURE BUILDS OVER
THE OHIO VALLEY.  EASTERLY FLOW AROUND THE RIDGE WILL PROMOTE A
SLIGHT CHANCE FOR SHOWERS ALONG THE FOOTHILLS OF SOUTHWEST NC DURING
THE AFTERNOON HOURS.  THE REST OF THE REGION SHOULD REMAIN DRY AS THE
AIRMASS REMAINS STABLE.  LATEST GFS/ECMWF GUIDANCE PLACES THE ABOVE
MENTIONED SURFACE RIDGE OFF THE EAST COAST BY THURSDAY MORNING. THIS
ALLOWS THE LOW LEVEL FLOW TO SHIFT TO THE SOUTHEAST PROMOTING
MARGINAL MOISTURE ADVECTION INTO THE PIEDMONT REGIONS OF NC AND SC.
HOWEVER...NAM GUIDANCE KEEPS THE FLOW OUT OF THE WEST NORTHWEST THUS
INHIBITING THE BULK OF THE MOISTURE AXIS FROM PUSHING BACK INTO
REGION.  BLENDED GFS/ECMWF INTO THE PREVIOUS FORECAST WHICH RESULTED
IN SLIGHT CHANCE DIURNAL POPS ACROSS THE REGION.  TEMPERATURES
DURING THE SHORT TERM PERIOD WILL REMAIN JUST A FEW DEGREES BELOW
NORMAL IN THE WAKE OF THE FROPA.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 130 PM EDT MONDAY...REINFORCING COLD FRONT WILL BE LOCATED
OVER THE SOUTHERN OHIO VALLEY BY LATE THURSDAY EVENING WHILE UPPER
LEVEL RIDGE SETTLES IN ACROSS THE CENTRAL PLAINS. STRONG SURFACE
HIGH PRESSURE WILL BUILD IN BEHIND THE ABOVE MENTIONED FRONTAL
BOUNDARY ACROSS THE GREAT LAKES REGION. AS THE BOUNDARY MOVES
THROUGH THE AREA ON FRIDAY...THE SURFACE HIGH OVER THE GREAT LAKES
WILL MIGRATE TO THE SOUTHEAST EVENTUALLY SETTING UP OVER CHESAPEAKE
BAY.  THIS WILL ALLOW FOR LOW LEVEL FLOW TO SHIFT EASTERLY THUS
PROMOTING UPSLOPE FLOW ALONG THE HIGH TERRAIN WHERE CHANCE POPS ARE
HIGHLIGHTED.  ELSEWHERE...SUBSIDENCE FROM THE RIDGE WILL MOST LIKELY
KEEP ANY CONVECTION AT BAY.  WITH THAT SAID...THERE WILL STILL BE
ENOUGH MOISTURE IN THE ATMOSPHERE TO ALLOW FOR SOME CONVECTION IF
THE RIDGE IS WEAKER THAN EXPECTED...ESPECIALLY ON THE WESTERN
PERIPHERY.  THUS MENTIONED SLIGHT CHANCE POPS OUTSIDE OF THE
MOUNTAINS FOR FRIDAY AFTERNOON.

THE SURFACE RIDGE SHIFTS FURTHER TO THE EAST ON SATURDAY ALLOWING
FOR LOW LEVEL FLOW TO VEER MORE SOUTHERLY.  EXPECTING INCREASING
MOISTURE ADVECTION WITH THIS PATTERN FOR SATURDAY AND INTO SUNDAY
WHERE DIURNAL POPS ARE HIGHLIGHTED IN THE FORECAST.  TEMPERATURES
THROUGH THE EXTENDED RANGE PERIOD WILL REMAIN A FEW DEGREES BELOW
NORMAL WITH A GRADUAL WARMING TREND SETTLING IN LATE IN THE
PERIOD.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AT KCLT...SOME OF THE NUMERICAL MODELS GENERATE CONVECTION OVER THE
NC PIEDMONT OVERNIGHT. THERE ARE A FEW TSTMS DEVELOPING OVER THE
FOOTHILLS ATTM. CONFIDENCE ISN/T NEARLY HIGH ENOUGH TO INCLUDE
THUNDER...BUT WE WILL KEEP A CLOSE EYE ON UPSTREAM TRENDS. HIGH CIGS
WILL CONTINUE OVERNIGHT...BUT WITH ANOTHER ROUND OF MVFR VSBY...AND
POSSIBLY BRIEF IFR CONDITIONS POSSIBLE TOWARD DAYBREAK. WILL
CONTINUE TO DAY SHIFTS FORECAST WITH SOME FEW010 TO INDICATE PATCHY
STRATUS. ANTICIPATE CUMULUS DEVELOPING WITH HEATING JUST AHEAD OF
THE FRONT ON TUE...WITH PROB30 NOW ADVERTISED 18Z TO 22Z. STEADY
LIGHT WSW FLOW WILL FINALLY TURN NW TOWARD THE END OF THE PERIOD.

ELSEWHERE...ISOLD SHRA/TSTMS HAVE DEVELOPED OVER THE SOUTHERN NC
MTNS AND THE UPSTATE WELL WEST OF GREENVILLE. CONVECTION MAY
APPROACH JUST ABOUT ANY SITE FROM KAVL DOWN TO KAND...BUT CHANCES
LOOK LOW. I/LL GO WITH VCSH FOR A FEW HOURS...BUT WILL HOLD OFF ON
ANY MORE AGGRESSIVE WORDING. ANOTHER ROUND OF IFR FOG AND CIGS LOOKS
LIKELY AT THE NC SITES TONIGHT...WITH MAINLY MVFR CONDITIONS
EXPECTED AT THE UPSTATE TAF SITES. CANNOT RULE OUT BRIEF IFR IN SC
AS WELL...BUT WITH LOW CONFIDENCE GIVEN THE POTENTIAL FOR MID AND
HIGH CLOUDS. FORCING WILL IMPROVE TUE MORNING BOTH ALOFT AND ALONG
THE APPROACHING FRONT...BUT INSTABILITY WILL BE THE MAIN QUESTION
FOR ANY TSRA. WILL FEATURE MAINLY VCSH AT THE TAF SITES...EXCEPT
VCTS AT KAND TOWARD MIDDAY.

OUTLOOK...A COLD FRONT WILL CROSS THE AREA LATE TUESDAY. DRIER AIR
WILL FOLLOW THE FRONTAL PASSAGE WED INTO THU...WITH HIGH PRESSURE
LINGERING INTO THE WEEKEND AS ATLANTIC MOISTURE RETURNS SLOWLY.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH 100%     HIGH  88%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH  87%     MED   67%     LOW   58%
KHKY       HIGH 100%     HIGH  91%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH  97%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH  97%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...HG
NEAR TERM...HG/MCAVOY
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...MCAVOY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 700 PM EDT MON SEP 2 2013

.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TONIGHT AND
THEN CROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA LATE ON
TUESDAY. DRY HIGH PRESSURE WILL FILL IN BEHIND THE FRONT ON
WEDNESDAY. HIGH PRESSURE WILL LINGER LATE THIS WEEK INTO THE
WEEKEND...WITH ATLANTIC MOISTURE SLOWLY RETURNING TO THE AREA.

&&

.NEAR TERM /THROUGH TUESDAY/...
AS OF 645 PM EDT...NOT MUCH CONVECTION HAS FIRED OVER THE REGION SO
FAR THIS EVENING. I/VE CUT BACK POPS TO ACCOUNT FOR THIS. SOME OF
THE CONVECTION ALLOWING MODELS GENERATE CONVECTION DURING THE COURSE
OF THE EVENING...INCLUDING THE HRRR WHICH BLOWS UP CONVECTION OVER
THE CHARLOTTE AREA...AND THE HIGH RES WRF WHICH BRINGS CONVECTION
INTO THE NC MTNS AFTER MIDNIGHT. WITH THESE SIGNALS I DID NOT REMOVE
POPS ALTOGETHER...THOUGH I DID KEEP THEM IN THE SLIGHT CHANCE TO LOW
END CHANCE RANGE AS THE CHANCES FOR RAIN AT ANY GIVEN LOCATION ARE
LOW.

AS OF 145 PM EDT...STILL ANTICIPATE MID TO LATE AFTN CONVECTION
DEVELOPING INITIALLY ALONG THE BLUE RIDGE...ALTHOUGH THE EARLY DAY
DEBRIS CLOUDS HAVE SLOWED THIS PROCESS A LITTLE. WESTERLY STEERING
FLOW SHOULD THEN TAKE SCT ACTIVITY EWD ACROSS THE FOOTHILLS LATE
THIS AFTN...BUT IT IS QUESTIONABLE HOW MUCH WILL SURVIVE INTO THE
ERN PIEDMONT. WILL STILL MAINTAIN CHC POPS OUT TO INTERSTATE
77...HOWEVER...SINCE SB CAPE VALUES ARE RUNNING 2000 TO 3000 J/KG IN
THAT AREA. ANY OUTFLOW DRIVEN CONVECTION WILL DIMINISH THIS EVENING
WITH LOSS OF DAYTIME HEATING AND WITH THE APPROACHING SFC COLD FRONT
REMAINING W OF THE APPALACHIANS.

FOR THE BIGGER PICTURE...AN UPPER LOW CENTER MOVING EWD FROM ONTARIO
CANADA INTO QUEBEC WILL SHARPEN UP AN ASSOCIATED LONGWAVE TROUGH
AXIS OVER THE ERN U.S. TONIGHT THROUGH TUESDAY. SHORTWAVE FEATURES
OF GREATER VORTICITY WILL BE HARD TO TIME IN THE LONGWAVE...BUT IT
APPEARS THE BEST UPPER SUPPORT WILL CROSS THE WRN CAROLINAS AND NE
GA MAINLY 12Z TO 18Z TUE. HOWEVER...THE SFC COLD FRONT SHOULD TRAIL
THE BETTER UPPER FORCING THROUGH THE DAY. WHILE MID AND UPPER DRYING
OCCURS BEHIND THE DEPARTING WAVE BY MIDDAY...THE SFC COLD FRONT WILL
LIKELY PASS THROUGH THE REGION DURING THE AFTN. WITH BOUNDARY LAYER
MOISTURE BEING SLOWEST TO DRY...ANOTHER ROUND OF SCATTERED
THUNDERSTORMS WILL BE POSSIBLE ALONG THE IMMEDIATE COLD FRONT MAINLY
IN AREAS SE OF INTERSTATE 85 TUE AFTN. STEEP EQUIVALENT POTENTIAL
TEMP LAPSES ACCOMPANYING THE IMMEDIATE FROPA WILL CREATE THE
POSSIBILITY FOR ISOLD WIND DAMAGE WITH ANY TSTMS. WILL CONTINUE TO
LEAN TOWARD THE BIAS CORRECTED GUIDANCE FOR MINS AND MAXES THROUGH
THE PERIOD UNTIL AFTER FROPA.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 110 PM EDT MONDAY...BROAD UPPER TROF WILL PERSIST THROUGH THE
PERIOD.  PASSING FRONTAL BOUNDARY SHOULD BE EXITING THE REGION TO
THE SOUTHEAST BY TUESDAY NIGHT.  IN RESPONSE...POPS WILL TAPER OFF
GRADUALLY DURING THE OVERNIGHT HOURS UNTIL ALL MENTION OF
PRECIPITATION IS REMOVED FROM THE FCST.  DRIER AIR WILL WORK INTO
THE REGION ON WEDNESDAY AS WEAK SURFACE HIGH PRESSURE BUILDS OVER
THE OHIO VALLEY.  EASTERLY FLOW AROUND THE RIDGE WILL PROMOTE A
SLIGHT CHANCE FOR SHOWERS ALONG THE FOOTHILLS OF SOUTHWEST NC DURING
THE AFTERNOON HOURS.  THE REST OF THE REGION SHOULD REMAIN DRY AS THE
AIRMASS REMAINS STABLE.  LATEST GFS/ECMWF GUIDANCE PLACES THE ABOVE
MENTIONED SURFACE RIDGE OFF THE EAST COAST BY THURSDAY MORNING. THIS
ALLOWS THE LOW LEVEL FLOW TO SHIFT TO THE SOUTHEAST PROMOTING
MARGINAL MOISTURE ADVECTION INTO THE PIEDMONT REGIONS OF NC AND SC.
HOWEVER...NAM GUIDANCE KEEPS THE FLOW OUT OF THE WEST NORTHWEST THUS
INHIBITING THE BULK OF THE MOISTURE AXIS FROM PUSHING BACK INTO
REGION.  BLENDED GFS/ECMWF INTO THE PREVIOUS FORECAST WHICH RESULTED
IN SLIGHT CHANCE DIURNAL POPS ACROSS THE REGION.  TEMPERATURES
DURING THE SHORT TERM PERIOD WILL REMAIN JUST A FEW DEGREES BELOW
NORMAL IN THE WAKE OF THE FROPA.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 130 PM EDT MONDAY...REINFORCING COLD FRONT WILL BE LOCATED
OVER THE SOUTHERN OHIO VALLEY BY LATE THURSDAY EVENING WHILE UPPER
LEVEL RIDGE SETTLES IN ACROSS THE CENTRAL PLAINS. STRONG SURFACE
HIGH PRESSURE WILL BUILD IN BEHIND THE ABOVE MENTIONED FRONTAL
BOUNDARY ACROSS THE GREAT LAKES REGION. AS THE BOUNDARY MOVES
THROUGH THE AREA ON FRIDAY...THE SURFACE HIGH OVER THE GREAT LAKES
WILL MIGRATE TO THE SOUTHEAST EVENTUALLY SETTING UP OVER CHESAPEAKE
BAY.  THIS WILL ALLOW FOR LOW LEVEL FLOW TO SHIFT EASTERLY THUS
PROMOTING UPSLOPE FLOW ALONG THE HIGH TERRAIN WHERE CHANCE POPS ARE
HIGHLIGHTED.  ELSEWHERE...SUBSIDENCE FROM THE RIDGE WILL MOST LIKELY
KEEP ANY CONVECTION AT BAY.  WITH THAT SAID...THERE WILL STILL BE
ENOUGH MOISTURE IN THE ATMOSPHERE TO ALLOW FOR SOME CONVECTION IF
THE RIDGE IS WEAKER THAN EXPECTED...ESPECIALLY ON THE WESTERN
PERIPHERY.  THUS MENTIONED SLIGHT CHANCE POPS OUTSIDE OF THE
MOUNTAINS FOR FRIDAY AFTERNOON.

THE SURFACE RIDGE SHIFTS FURTHER TO THE EAST ON SATURDAY ALLOWING
FOR LOW LEVEL FLOW TO VEER MORE SOUTHERLY.  EXPECTING INCREASING
MOISTURE ADVECTION WITH THIS PATTERN FOR SATURDAY AND INTO SUNDAY
WHERE DIURNAL POPS ARE HIGHLIGHTED IN THE FORECAST.  TEMPERATURES
THROUGH THE EXTENDED RANGE PERIOD WILL REMAIN A FEW DEGREES BELOW
NORMAL WITH A GRADUAL WARMING TREND SETTLING IN LATE IN THE
PERIOD.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AT KCLT...MORNING DEBRIS CLOUDS ARRIVING FROM THE W HAVE LARGELY
SQUASHED CONVECTION IN ALL AREAS UPSTREAM OF KCLT. STILL ANTICIPATE
SOME TSRA DEVELOPMENT BACK OVER THE ERN SLOPES OF THE MTNS...BUT
THIS WILL TAKE A WHILE TO REACH THE KCLT VICINITY IN WEAK WESTERLY
STEERING FLOW. THUS FEEL THAT TEMPO TSRA IS NOT WARRANTED THIS AFTN.
WILL THUS JUST MENTION VCSH FROM 21Z TO 01Z FOR ANY PRECIP THAT
MAKES A RUN TOWARD THE AIRFIELD. MAINLY CONTINUED HIGH LEVEL CIGS
ARE EXPECTED OVERNIGHT...BUT WITH ANOTHER ROUND OF MVFR VSBY...AND
POSSIBLY BRIEF IFR CONDITIONS POSSIBLE TOWARD DAYBREAK. NONE OF THE
MOS HAS THIS...BUT THE MOS HAS BEEN QUITE POOR RECENTLY. WILL HINT
AT THE LOW CLOUDS WITH SOME FEW010. ANTICIPATE CUMULUS DEVELOPING
WITH HEATING JUST AHEAD OF THE FRONT ON TUE...WITH PROB30 NOW
ADVERTISED 16Z TO 18Z. STEADY LIGHT WSW FLOW WILL FINALLY TURN NW
TOWARD THE END OF THE PERIOD.

ELSEWHERE...CONVECTION IS OFF TO A VERY SLOW START AROUND THE REGION
THIS AFTN GIVEN THE SUPPRESSING EFFECTS OF THE HIGH LEVEL DEBRIS
CLOUDS TODAY. ANTICIPATE THE INITIAL DEVELOPMENT TO STILL OCCUR
AROUND 19Z TO 20Z ALONG THE ERN SLOPES OF THE MTNS...AFFECTING
MAINLY KAVL MID AFTN...THEN POSSIBLY THE VICINITY OF THE FOOTHILL
TAFS MID TO LATE AFTN IN WESTERLY STEERING FLOW. COVERAGE WILL
DIMINISH QUICKLY THIS EVENING...BUT ISOLD SHRA WILL BE POSSIBLE
OVERNIGHT...ESPECIALLY NEAR KAVL CLOSER TO THE APPROACHING COLD
FRONT. ANOTHER ROUND OF IFR FOG AND CIGS LOOKS LIKELY AT THE NC
SITES TONIGHT...WITH MAINLY MVFR CONDITIONS EXPECTED AT THE UPSTATE
TAF SITES. CANNOT RULE OUT BRIEF IFR IN SC AS WELL...BUT WITH LOW
CONFIDENCE GIVEN THE POTENTIAL FOR MID AND HIGH CLOUDS. FORCING WILL
IMPROVE TUE MORNING BOTH ALOFT AND ALONG THE APPROACHING FRONT...BUT
INSTABILITY WILL BE THE MAIN QUESTION FOR ANY TSRA. WILL FEATURE
MAINLY VCSH AT THE TAF SITES...EXCEPT VCTS AT KAND TOWARD MIDDAY.

OUTLOOK...A COLD FRONT WILL CROSS THE AREA LATE TUESDAY. DRIER AIR
WILL FOLLOW THE FRONTAL PASSAGE WED INTO THU...WITH HIGH PRESSURE
LINGERING INTO THE WEEKEND AS ATLANTIC MOISTURE RETURNS SLOWLY.

CONFIDENCE TABLE...

            23-05Z        05-11Z        11-17Z        17-23Z
KCLT       HIGH 100%     HIGH  95%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH  92%     MED   68%     HIGH  80%
KHKY       HIGH 100%     HIGH  91%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH  95%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...HG
NEAR TERM...HG/MCAVOY
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 204 PM EDT SUN SEP 1 2013

.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE AREA AS WEAK HIGH
PRESSURE SLOWLY SLIDES OFFSHORE THIS EVENING. THIS MOIST FLOW WILL HELP TO
KICK OFF SHOWERS AND THUNDERSTORMS THROUGH LABOR DAY. A COLD FRONT
WILL CROSS THE CAROLINAS ON TUESDAY WITH DRY HIGH PRESSURE RETURNING
ON WEDNESDAY. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
RETURN BY NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM...I WILL INCREASE NEAR TERM POPS TO MATCH RECENT RADAR
IMAGES. BASED ON OBS...I WILL INCREASE DWPTS THROUGH THE REST OF THE
AFTERNOON. CURRENT HWO REMAINS REPRESENTATIVE.

AS OF NOON...REGIONAL RADAR SHOWS A FADING LINE OF SHRA/TSRA IS
CROSSING THE NRN MTNS AS AN AREA OF SHOWERS AND TSRA OVER NRN GA.
THE CONVECTION APPEARS TO BE SUPPORTED BY THE APPROACH OF A S/W
RIPPLING ACROSS EASTERN KY/TN. LATEST MESOSCALE ANALYSIS SHOWS THAT
CAPES ACROSS THE CWA RANGE FROM 1000 J/KG ACROSS THE MTNS TO
EXCEEDING 2500 J/KG ACROSS THE UPPER SAVANNAH RIVER VALLEY. SIMILAR
TO SATURDAY...THE FORECAST AREA WILL LIKELY SEE AFTERNOON DEWPOINTS
IN THE LOW TO MID 70S WITH HIGHS IN THE U80S. OBSERVED SOUNDING AT
KFFC THIS MORNING INDICATED THAT THIS AFTERNOON CAPES COULD APPROACH
3500 J/KG...THIS MAY APPLY TO OUR FOOTHILLS AND PIEDMONT. DCAPE
VALUES MAY CONTINUE TO RANGE BELOW 1000 J/KG. KFFC AND KGSO FZL
ABOVE 14 KFT/WBZ ABOVE 12 KFT AND WEAK SHEAR WILL NOT FAVOR SVR WX.
HOWEVER...THE MODERATELY UNSTABLE ENVIRONMENT COUPLED WITH
INCREASING UPPER SUPPORT WILL LIKELY RESULT IN A BROAD BAND OF TSRA
FORMING OVER THE MTNS THIS AFTERNOON...TRACKING EAST DURING THE
EVENING. THESE STORMS COULD PRODUCE GUSTY WINDS AND TORRENTIAL
RAINFALL...HIGHLIGHTED WELL IN THE HWO.

I WILL UPDATE THE FORECAST TO ADJUST SKY/POP/AND TEMPS TO THE LATEST
THINKING. THE MOST NOTABLE CHANGES WILL BE CARRYING SOLID CHC POPS
WELL INTO THE EVENING HOURS ACROSS THE FOOTHILLS AND PIEDMONT.

5 AM UPDATE...SHRA/TSRA MOVING INTO THE SW MTNS ARE HAVING TROUBLE
PUSHING FURTHER EAST...BUT WEAK UPSLOPE FLOW AND CONTINUING ELEVATED
INSTBY MAY ALLOW SOME MORE DEVELOPMENT THERE. HRRR AND RAP BRING
SOME ACTIVITY FROM DECAYING TENN VALLEY MCS ACRS THE NC BORDER JUST
AFTER DAYBREAK. IT IS LOOKING LESS AND LESS ORGANIZED...SO DON/T
HAVE A LOT OF CONFIDENCE THAT WILL HAPPEN...BUT FELT IT WAS A GOOD
IDEA TO RAISE POPS SLIGHTLY NEAR THE BORDER EARLY THIS MRNG.

AS OF EARLY SUNDAY MORNING...WESTERLY FLOW INTO THE MTNS IS MAKING
THE MOST OF THE FEW HUNDRED JOULES OF MUCAPE STILL PRESENT OVER EAST
TN...ALLOWING A FEW CELLS TO FIRE UP THERE AS OF 315 AM. THOUGH THE
INSTABILITY WILL LIKELY WANE SOMEWHAT THRU DAYBREAK...GIVEN THE
CONTINUED WLY LLVL WINDS HAVE KEPT ISOLD PRECIP MENTION NEAR THE
TENN BORDER INTO THE MORNING. THE REMAINING PRECIP SHIELD FROM AN
MCS WHICH MOVED THRU THE CUMBERLAND PLATEAU EARLIER IS MOVING TOWARD
THE NC BORDER...BUT THIS MAY DISSOLVE BEFORE IT GETS TO OUR CWFA.
ALSO NOTING A SECOND MCS OVER KY ON RADAR. STORM MOTION /FWD-PROP
CORFIDI VECTOR/ FROM 00Z NASHVILLE SOUNDING SUGGESTS THIS WILL MOVE
WEST OF OUR AREA...AND THIS IS BACKED UP BY 00Z SPC WRF. ON
ANOTHER NOTE...LOW CLOUDS AND FOG NOW WIDESPREAD IN THE MTNS AND
SPOTTY IN THE FOOTHILLS MAY WORSEN A BIT TOWARD DAYBREAK THOUGH WITH
TEMPS NEARLY STEADY I THINK VSBY NOT GET TOO MUCH WORSE. IF DENSE
FOG SETTLES INTO A LARGE CONTIGUOUS AREA A DENSE FOG ADVY MAY BE
NEEDED.

STILL EXPECTING A RELATIVELY SIMILAR SITUATION TODAY COMPARED TO
YESTERDAY. THE CWFA REMAINS UNDER CYCLONIC UPPER FLOW WITH A FEW
EMBEDDED EDDIES POTENTIALLY HELPING TO DRIVE CONVECTION. REGARDING
THAT CONVECTION...NAM/GFS REMARKABLY DIFFERENT IN CAPE PROGS FOR
TODAY...WITH THE GFS FEATURING SUSPICIOUSLY HIGH VALUES IN THE
MTNS...ABOVE 4000 J/KG AT MIDDAY. NAM SEEMS TO REFLECT THE DELAYED
WARMING DUE TO THE LOW CLOUDS IN THE MTNS...RAMPING UP INSTABILITY
FIRST IN THE PIEDMONT AND KEEPING THE HIGHEST VALUES THERE OVERALL.
THIS ALSO INDICATED BY SREF PROBS. THIS IS PLAUSIBLE SO I BROUGHT
POPS UP THERE FIRST...BUT THE MTNS WILL LIKELY EVENTUALLY
DESTABILIZE AND WITH SWLY UPSLOPE FLOW THEY WILL STILL SEE THE
HIGHEST CHANCES BY MID AFTN.

TONIGHT SOME ISENTROPIC LIFT IS NOTED ON 305K SURFACE FROM
NAM/GFS...PERHAPS DUE TO WEAK WAA AS THE UPPER TROUGH SHIFTS SLOWLY
EASTWARD. OTHERWISE THE PATTERN REMAINS ABOUT THE SAME...STILL
SUPPORTIVE OF SOME NOCTURNAL CONVECTION...SO I HAVE KEPT SCT SHOWERS
OVERNIGHT IN THE MTNS/FOOTHILLS AND ISOLD IN THE PIEDMONT. LOWS
TONIGHT MAY BE A TAD WARMER WITH SLIGHTLY HIGHER THICKNESSES.

SHEAR WILL BE WEAK ENOUGH TO PRECLUDE MOST SEVERE WEATHER...BUT
GIVEN THE INSTABILITY WOULD NOT BE SURPRISED TO SEE A COUPLE STORMS
PRODUCE STRONG TO SEVERE WINDS. VERY SLOW CORFIDI VECTORS INDICATE
HEAVY RAIN AND FLASH FLOODING STILL A THREAT.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 140 PM SUNDAY...UPPER LEVEL L/WV TROUGH AXIS IS SLATED FOR
PASSAGE SOME TIME TUESDAY MORNING WITH THE BETTER LARGE SCALE FORCING
DEVELOPING TOWARD THE COAST TUESDAY AFTERNOON. AT THE SFC...WEAK
COLD FRONT NW OF THE MTNS MONDAY NIGHT REMAINS PROGGED TO JUMP INTO
EXISTING LEE TROUGH POSITION ON TUESDAY. WITHIN THE BROAD UVV/S ALONG
FRONT SIDE OF UPPER TROUGH...AT LEAST SMALL POP WILL NEED TO BE IN
THE FCST ALL NIGHT INTO TUESDAY MORNING. AS TUESDAY WEARS ON...THE
INFLUX OF DRIER LLVL AIR WOULD SEEM TO INCREASINGLY LIMIT DIURNAL
DEEP CONVECTIVE CHANCES TO AREAS E/SE OF THE BLUE RIDGE...ROUGHLY
COINCIDENT WITH THE EASTWARD PROGRESSION OF THE FRONTAL BOUNDARY.

DEEP LAYERED DRY AIR AND WEAK RIDGING ARE STILL EXPECTED TO SPREAD
INTO THE REGION THROUGH WEDNESDAY RESULTING IN QUIET WX CONDS AND
MAX TEMPERATURES A COUPLE OF DEG F BELOW THE EARLY SEPT CLIMO.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 1 PM SUNDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
THURSDAY WITH THE STEEP UPPER RIDGE PERSISTING OVER THE WESTERN
CONUS AND BROAD UPPER TROFFING OVER THE EAST. THIS PATTERN WILL
LARGELY MAINTAIN ITSELF UNTIL A CLOSED H5 LOW SPINS UP OVER THE
PACIFIC NW ON FRI AND THEN GRADUALLY SLIDES EASTWARD AND UP OVER THE
RIDGE. THE LONG RANGE MODELS SUGGEST THAT THIS LOW WILL ACT TO
FLATTEN THE UPPER RIDGE TOWARDS THE END OF THE PERIOD ON
SUN...LEAVING A MORE ZONAL SYNOPTIC PATTERN OVER MOST OF THE CONUS.
AT THE SFC...DRY CANADIAN HIGH PRESSURE WILL BE SLIDING OVER THE
REGION WITH WEAK FLOW AT THE SFC AND ALOFT. AS WE MOVE INTO FRI AND
THE WEEKEND...THE BERMUDA HIGH WILL GRADUALLY SPREAD MOIST SLY FLOW
OVER THE FCST AREA WITH INCREASING CHANCES FOR SCT SH AND TS EACH
DAY/EVENING. TEMPS SHOULD START THE PERIOD NEAR CLIMO AND DROP A
DEGREE OR 2 BY DAYS 6 AND 7.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT...LATEST VISIBLE SATELLITE IMAGES AND WEB CAMS INDICATE
WEAKLY DEVELOPED CU ACROSS THE TERMINAL AT TAF ISSUANCE TIME.
REGIONAL RADARS INDICATE A FEW TSRA BANDS EXITING THE
FOOTHILLS...ON A TRACK TO MOVE NORTH AND SOUTH OF THE TERMINAL.
HOWEVER...THE SPC SSEO INDICATES THAT CONVECTION WILL RAPIDLY
DEVELOP OVER THE MTNS LATER THIS AFTERNOON AS A MODERATE S/W MOVES
TOWARD THE SOUTHERN APPALACHIANS. STEERING FLOW SHOULD BRING THE
CONVECTION ACROSS THE TERMINAL BETWEEN 22Z TO 2Z. SFC WINDS AHEAD OF
THE CONVECTION SHOULD REMAIN SW AROUND 10 KTS. FOLLOWING THE PASSAGE
OF THE STORMS...THICK DEBRIS CLOUDS SHOULD REMAIN OVER THE REGION
FOR MOST OF THE NIGHT. VFR FOG MAY DEVELOP OVER RAIN SOAKED AREAS
AROUND DAWN. ONE OR TWO HOURS AFTER SUNRISE MONDAY...WITH SHOULD
INCREASE TO AROUND 5 KTS FROM THE WSW WITH SCT CU BASES AROUND 030.

ELSEWHERE...KAND/KGSP/KGMU/KAVL WILL HAVE A GOOD CHANCE FOR
OBSERVING A SHRA OR TSRA DURING THE BEGINNING HOURS OF THE 18Z TAF.
I WILL INCLUDE A MENTION OF TEMPO FOR TS OR VCTS FOR EACH SITE. KHKY
SHOULD SEE VCTS BY 21Z. THE SPC SSEO INDICATES THAT CONVECTION WILL
RAPIDLY DEVELOP OVER THE MTNS LATER THIS AFTERNOON AS A MODERATE S/W
MOVES TOWARD THE SOUTHERN APPALACHIANS. STEERING FLOW SHOULD BRING
THE CONVECTION ACROSS THE TERMINALS THROUGH EARLY EVENING. SFC WINDS AHEAD
OF THE CONVECTION SHOULD REMAIN SW AROUND 10 KTS. FOLLOWING THE
PASSAGE OF THE STORMS...THICK DEBRIS CLOUDS SHOULD REMAIN OVER THE
REGION FOR MOST OF THE NIGHT. MVFR FOG MAY DEVELOP OVER RAIN SOAKED
AREAS AROUND DAWN. FORECAST SOUNDINGS INDICATE THAT KAVL WILL LIKELY
SEE ANOTHER PERIOD AROUND DAWN OF LIFR FOG AND CEILINGS. ONE OR TWO
HOURS AFTER SUNRISE MONDAY...WITH SHOULD INCREASE TO AROUND 5 KTS
FROM THE WSW WITH SCT CU WITH VFR BASES.

OUTLOOK...DIURNALLY DRIVEN ISOLD TO SCT CONVECTION EXPECTED AGAIN
MONDAY. DAYBREAK FOG WILL BE MOST LIKELY IN MOUNTAIN VALLEYS AND
WHERE RAIN FELL THE DAY BEFORE. A COLD FRONT WILL CROSS THE AREA ON
TUESDAY...BUT CONVECTIVE CHANCES ARE UNCERTAIN AT THIS TIME. DRIER
AIR WILL FOLLOW THE FRONT.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH  85%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH  97%     HIGH  83%     HIGH 100%
KAVL       HIGH 100%     HIGH  97%     MED   68%     HIGH  85%
KHKY       HIGH  85%     HIGH 100%     HIGH  83%     HIGH  94%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  97%
KAND       HIGH 100%     HIGH 100%     HIGH  99%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...JPT
NEAR TERM...NED/WIMBERLEY
SHORT TERM...CSH
LONG TERM...JPT
AVIATION...NED







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 1201 PM EDT SUN SEP 1 2013

.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE AREA AS WEAK HIGH
PRESSURE SLOWLY SLIDES OFFSHORE TODAY. THIS MOIST FLOW WILL HELP TO
KICK OFF SHOWERS AND THUNDERSTORMS THROUGH LABOR DAY. A COLD FRONT
CROSSES THE AREA TUESDAY WITH DRY HIGH PRESSURE RETURNING ON
WEDNESDAY. MOISTURE AND SCATTERED THUNDERSTORMS RETURN BY NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF NOON...REGIONAL RADAR SHOWS A FADING LINE OF SHRA/TSRA IS
CROSSING THE NRN MTNS AS AN AREA OF SHOWERS AND TSRA OVER NRN GA.
THE CONVECTION APPEARS TO BE SUPPORTED BY THE APPROACH OF A S/W
RIPPLING ACROSS EASTERN KY/TN. LATEST MESOSCALE ANALYSIS SHOWS THAT
CAPES ACROSS THE CWA RANGE FROM 1000 J/KG ACROSS THE MTNS TO
EXCEEDING 2500 J/KG ACROSS THE UPPER SAVANNAH RIVER VALLEY. SIMILAR
TO SATURDAY...THE FORECAST AREA WILL LIKELY SEE AFTERNOON DEWPOINTS
IN THE LOW TO MID 70S WITH HIGHS IN THE U80S. OBSERVED SOUNDING AT
KFFC THIS MORNING INDICATED THAT THIS AFTERNOON CAPES COULD APPROACH
3500 J/KG...THIS MAY APPLY TO OUR FOOTHILLS AND PIEDMONT. DCAPE
VALUES MAY CONTINUE TO RANGE BELOW 1000 J/KG. KFFC AND KGSO FZL
ABOVE 14 KFT/WBZ ABOVE 12 KFT AND WEAK SHEAR WILL NOT FAVOR SVR WX.
HOWEVER...THE MODERATELY UNSTABLE ENVIRONMENT COUPLED WITH
INCREASING UPPER SUPPORT WILL LIKELY RESULT IN A BROAD BAND OF TSRA
FORMING OVER THE MTNS THIS AFTERNOON...TRACKING EAST DURING THE
EVENING. THESE STORMS COULD PRODUCE GUSTY WINDS AND TORRENTIAL
RAINFALL...HIGHLIGHTED WELL IN THE HWO.

I WILL UPDATE THE FORECAST TO ADJUST SKY/POP/AND TEMPS TO THE LATEST
THINKING. THE MOST NOTABLE CHANGES WILL BE CARRYING SOLID CHC POPS
WELL INTO THE EVENING HOURS ACROSS THE FOOTHILLS AND PIEDMONT.

5 AM UPDATE...SHRA/TSRA MOVING INTO THE SW MTNS ARE HAVING TROUBLE
PUSHING FURTHER EAST...BUT WEAK UPSLOPE FLOW AND CONTINUING ELEVATED
INSTBY MAY ALLOW SOME MORE DEVELOPMENT THERE. HRRR AND RAP BRING
SOME ACTIVITY FROM DECAYING TENN VALLEY MCS ACRS THE NC BORDER JUST
AFTER DAYBREAK. IT IS LOOKING LESS AND LESS ORGANIZED...SO DON/T
HAVE A LOT OF CONFIDENCE THAT WILL HAPPEN...BUT FELT IT WAS A GOOD
IDEA TO RAISE POPS SLIGHTLY NEAR THE BORDER EARLY THIS MRNG.

AS OF EARLY SUNDAY MORNING...WESTERLY FLOW INTO THE MTNS IS MAKING
THE MOST OF THE FEW HUNDRED JOULES OF MUCAPE STILL PRESENT OVER EAST
TN...ALLOWING A FEW CELLS TO FIRE UP THERE AS OF 315 AM. THOUGH THE
INSTABILITY WILL LIKELY WANE SOMEWHAT THRU DAYBREAK...GIVEN THE
CONTINUED WLY LLVL WINDS HAVE KEPT ISOLD PRECIP MENTION NEAR THE
TENN BORDER INTO THE MORNING. THE REMAINING PRECIP SHIELD FROM AN
MCS WHICH MOVED THRU THE CUMBERLAND PLATEAU EARLIER IS MOVING TOWARD
THE NC BORDER...BUT THIS MAY DISSOLVE BEFORE IT GETS TO OUR CWFA.
ALSO NOTING A SECOND MCS OVER KY ON RADAR. STORM MOTION /FWD-PROP
CORFIDI VECTOR/ FROM 00Z NASHVILLE SOUNDING SUGGESTS THIS WILL MOVE
WEST OF OUR AREA...AND THIS IS BACKED UP BY 00Z SPC WRF. ON
ANOTHER NOTE...LOW CLOUDS AND FOG NOW WIDESPREAD IN THE MTNS AND
SPOTTY IN THE FOOTHILLS MAY WORSEN A BIT TOWARD DAYBREAK THOUGH WITH
TEMPS NEARLY STEADY I THINK VSBY NOT GET TOO MUCH WORSE. IF DENSE
FOG SETTLES INTO A LARGE CONTIGUOUS AREA A DENSE FOG ADVY MAY BE
NEEDED.

STILL EXPECTING A RELATIVELY SIMILAR SITUATION TODAY COMPARED TO
YESTERDAY. THE CWFA REMAINS UNDER CYCLONIC UPPER FLOW WITH A FEW
EMBEDDED EDDIES POTENTIALLY HELPING TO DRIVE CONVECTION. REGARDING
THAT CONVECTION...NAM/GFS REMARKABLY DIFFERENT IN CAPE PROGS FOR
TODAY...WITH THE GFS FEATURING SUSPICIOUSLY HIGH VALUES IN THE
MTNS...ABOVE 4000 J/KG AT MIDDAY. NAM SEEMS TO REFLECT THE DELAYED
WARMING DUE TO THE LOW CLOUDS IN THE MTNS...RAMPING UP INSTABILITY
FIRST IN THE PIEDMONT AND KEEPING THE HIGHEST VALUES THERE OVERALL.
THIS ALSO INDICATED BY SREF PROBS. THIS IS PLAUSIBLE SO I BROUGHT
POPS UP THERE FIRST...BUT THE MTNS WILL LIKELY EVENTUALLY
DESTABILIZE AND WITH SWLY UPSLOPE FLOW THEY WILL STILL SEE THE
HIGHEST CHANCES BY MID AFTN.

TONIGHT SOME ISENTROPIC LIFT IS NOTED ON 305K SURFACE FROM
NAM/GFS...PERHAPS DUE TO WEAK WAA AS THE UPPER TROUGH SHIFTS SLOWLY
EASTWARD. OTHERWISE THE PATTERN REMAINS ABOUT THE SAME...STILL
SUPPORTIVE OF SOME NOCTURNAL CONVECTION...SO I HAVE KEPT SCT SHOWERS
OVERNIGHT IN THE MTNS/FOOTHILLS AND ISOLD IN THE PIEDMONT. LOWS
TONIGHT MAY BE A TAD WARMER WITH SLIGHTLY HIGHER THICKNESSES.

SHEAR WILL BE WEAK ENOUGH TO PRECLUDE MOST SEVERE WEATHER...BUT
GIVEN THE INSTABILITY WOULD NOT BE SURPRISED TO SEE A COUPLE STORMS
PRODUCE STRONG TO SEVERE WINDS. VERY SLOW CORFIDI VECTORS INDICATE
HEAVY RAIN AND FLASH FLOODING STILL A THREAT.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 220 AM SUN...A WEAK UPPER TROF REMAINS OVER THE AREA MONDAY
WITH THE TROF AXIS SHIFTING OFF SHORE TUE WITH NWLY FLOW DEVELOPING
WED. AT THE SFC...A LEE TROF REMAINS OVER THE AREA MONDAY KEEPING A
MOIST S TO SWLY LOW LEVEL FLOW IN PLACE. A WEAK COLD FRONT JUMPS
INTO THE TROF TUE AND SLIDES OFF SHORE TUE NITE AND WED. WITH DEEP
MOISTURE IN PLACE MON...MODERATE INSTABILITY DEVELOPS LEADING TO
ANOTHER DAY OF CONVECTION FAVORING THE MTNS WITH ONLY SLIGHTLY LOWER
CHC ELSEWHERE. LOW LEVEL FLOW BECOMES WLY TUE AS THE FRONT JUMPS
INTO THE LEE TROF. HOWEVER...ENUF LOW LEVEL MOISTURE REMAINS TO
PRODUCE SCT CONVECTION WITH THE DEVELOPING MODERATE INSTABILITY.
CONVECTION SHUD QUICKLY DIMINISH TUE NITE WITH LOSS OF HEATING.
WITH DRIER HIGH PRESSURE MOVING IN WED...EXPECT ONLY CLOUDS WITH THE
LINGERING LOW LEVEL MOISTURE. HIGHS WILL BE STEADY NEAR OR A LITTLE
ABOVE NORMAL MON AND TUE...THEN DROP TO SLIGHTLY BELOW NORMAL WED.
LOWS ABOUT 5 DEGREES ABOVE NORMAL MON NITE DROP TO NEAR NORMAL TUE
NITE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 315 AM SUN...THE MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT
THRU THE PERIOD. A SERIES OF SHORT WAVES DROP THRU THE NWLY FLOW
OVER THE AREA. THIS CAUSES A KINK IN THE FLOW CREATING A WEAK TROF
OVER THE SERN US BY FRI WHICH STRENGTHENS ON SAT. DRY HIGH PRESSURE
STARTS OVER THE AREA THU. THERE IS SOME LINGERING LOW LEVEL MOISTURE
AND WEAK ELY LOW LEVEL FLOW. HOWEVER...EXPECT ONLY CLOUDS TO DEVELOP
DURING THE DAY. A WEAK BACK DOOR COLD FRONT DROPS INTO THE AREA FRI
WHICH COULD HELP PRODUCE ISOLATED DIURNAL CONVECTION. SCT DIURNAL
CONVECTION EXPECTED SAT AS LOW LEVEL FLOW BECOMES SLY BRINGING
BETTER MOISTURE AND INSTABILITY BACK INTO THE AREA. HIGHS START NEAR
NORMAL AND FALL A LITTLE BELOW BY SAT. LOWS START OUT A LITTLE BELOW
NORMAL AND RISE TO NEAR NORMAL.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
AT KCLT...SMALL POSSIBILITY OF A LOW CIG SETTLING IN AROUND DAYBREAK
AND KEEPING A RESTRICTION AFTER 12Z...BUT PRETTY CONFIDENT IN VFR TO
START THE TAF. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY AND
HAVE THEM IN A TEMPO IN THE EARLY TO MID AFTN...AND A VCSH
SURROUNDING TO REFLECT A LOWER PROBABILITY SURROUNDING THIS PERIOD.
FOLLOWING THE END OF THE DIURNAL CONVECTION VFR WILL PREVAIL...BUT
GUIDANCE SUGGESTS SOME FOG POSSIBLE LATE TONIGHT ONCE AGAIN. THIS IS
ESPECIALLY LIKELY IF THE FIELD IS HIT BY A SHOWER OR TSTM TODAY.

ELSEWHERE...EARLY MORNING DENSE FOG AND LIFR TO VLIFR CLOUD BASES
EXPECTED ACROSS THE MTNS TO THE WESTERN PIEDMONT EARLY THIS MORNING.
CLIMO INDICATES THAT CONDITIONS MAY NOT IMPROVE TO VFR UNTIL 14Z.
SOME CONVECTION MAY MOVE INTO THE MTNS FROM THE WEST EARLY TODAY
THOUGH CURRENT TRENDS SUGGEST LITTLE DIRECT THREAT TO KAVL OR ANY
OTHER TAF SITE. HOWEVER DIURNAL INSTABILITY WILL GROW QUICKLY ONCE
THE LOW CIGS BURN OFF. KAVL AND THE MTNS WILL LIKELY SEE SHRA/TSRA
THIS AFTN. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY AND WILL
KEEP TEMPOS DURING THE AFTERNOON AS WELL AS A VCSH/VCTS AS NECESSARY
TO INDICATE LESSER PROBABILITY IN THE SURROUNDING TIMEFRAME. FLOW
REMAINS GENERALLY SOUTHWESTERLY /EXCEPT NW IN UP-VALLEY FLOW AT
KAVL/ INTO TONIGHT. WITH LITTLE CHANGE IN THE PATTERN...A SIMILAR
NIGHT IS LIKELY TO UNFOLD TONIGHT...THOUGH RESTRICTIONS WILL MAINLY
COME FROM FOG. SITES AFFECTED BY TSRA/SHRA TODAY ARE MOST LIKELY TO
GO DOWN TONIGHT...BUT IN GENERAL MOST SITES HAVE A GOOD SHOT AT
SEEING AT LEAST MVFR VSBY BEFORE DAYBREAK.

OUTLOOK...DIURNALLY DRIVEN ISOLD TO SCT CONVECTION EXPECTED AGAIN
MONDAY. DAYBREAK FOG WILL BE MOST LIKELY IN MOUNTAIN VALLEYS AND
WHERE RAIN FELL THE DAY BEFORE. A COLD FRONT WILL CROSS THE AREA ON
TUESDAY...BUT CONVECTIVE CHANCES ARE UNCERTAIN AT THIS TIME. DRIER
AIR WILL FOLLOW THE FRONT.

CONFIDENCE TABLE...

            16-22Z        22-04Z        04-10Z        10-16Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  93%     HIGH 100%     HIGH  82%     MED   75%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...RWH
NEAR TERM...NED/WIMBERLEY
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...NED/WIMBERLEY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 743 AM EDT SUN SEP 1 2013

.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE AREA AS WEAK HIGH
PRESSURE SLOWLY SLIDES OFFSHORE TODAY. THIS MOIST FLOW WILL HELP TO
KICK OFF SHOWERS AND THUNDERSTORMS THROUGH LABOR DAY. A COLD FRONT
CROSSES THE AREA TUESDAY WITH DRY HIGH PRESSURE RETURNING ON
WEDNESDAY. MOISTURE AND SCATTERED THUNDERSTORMS RETURN BY NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
5 AM UPDATE...SHRA/TSRA MOVING INTO THE SW MTNS ARE HAVING TROUBLE
PUSHING FURTHER EAST...BUT WEAK UPSLOPE FLOW AND CONTINUING ELEVATED
INSTBY MAY ALLOW SOME MORE DEVELOPMENT THERE. HRRR AND RAP BRING
SOME ACTIVITY FROM DECAYING TENN VALLEY MCS ACRS THE NC BORDER JUST
AFTER DAYBREAK. IT IS LOOKING LESS AND LESS ORGANIZED...SO DON/T
HAVE A LOT OF CONFIDENCE THAT WILL HAPPEN...BUT FELT IT WAS A GOOD
IDEA TO RAISE POPS SLIGHTLY NEAR THE BORDER EARLY THIS MRNG.

AS OF EARLY SUNDAY MORNING...WESTERLY FLOW INTO THE MTNS IS MAKING
THE MOST OF THE FEW HUNDRED JOULES OF MUCAPE STILL PRESENT OVER EAST
TN...ALLOWING A FEW CELLS TO FIRE UP THERE AS OF 315 AM. THOUGH THE
INSTABILITY WILL LIKELY WANE SOMEWHAT THRU DAYBREAK...GIVEN THE
CONTINUED WLY LLVL WINDS HAVE KEPT ISOLD PRECIP MENTION NEAR THE
TENN BORDER INTO THE MORNING. THE REMAINING PRECIP SHIELD FROM AN
MCS WHICH MOVED THRU THE CUMBERLAND PLATEAU EARLIER IS MOVING TOWARD
THE NC BORDER...BUT THIS MAY DISSOLVE BEFORE IT GETS TO OUR CWFA.
ALSO NOTING A SECOND MCS OVER KY ON RADAR. STORM MOTION /FWD-PROP
CORFIDI VECTOR/ FROM 00Z NASHVILLE SOUNDING SUGGESTS THIS WILL MOVE
WEST OF OUR AREA...AND THIS IS BACKED UP BY 00Z SPC WRF. ON
ANOTHER NOTE...LOW CLOUDS AND FOG NOW WIDESPREAD IN THE MTNS AND
SPOTTY IN THE FOOTHILLS MAY WORSEN A BIT TOWARD DAYBREAK THOUGH WITH
TEMPS NEARLY STEADY I THINK VSBY NOT GET TOO MUCH WORSE. IF DENSE
FOG SETTLES INTO A LARGE CONTIGUOUS AREA A DENSE FOG ADVY MAY BE
NEEDED.

STILL EXPECTING A RELATIVELY SIMILAR SITUATION TODAY COMPARED TO
YESTERDAY. THE CWFA REMAINS UNDER CYCLONIC UPPER FLOW WITH A FEW
EMBEDDED EDDIES POTENTIALLY HELPING TO DRIVE CONVECTION. REGARDING
THAT CONVECTION...NAM/GFS REMARKABLY DIFFERENT IN CAPE PROGS FOR
TODAY...WITH THE GFS FEATURING SUSPICIOUSLY HIGH VALUES IN THE
MTNS...ABOVE 4000 J/KG AT MIDDAY. NAM SEEMS TO REFLECT THE DELAYED
WARMING DUE TO THE LOW CLOUDS IN THE MTNS...RAMPING UP INSTABILITY
FIRST IN THE PIEDMONT AND KEEPING THE HIGHEST VALUES THERE OVERALL.
THIS ALSO INDICATED BY SREF PROBS. THIS IS PLAUSIBLE SO I BROUGHT
POPS UP THERE FIRST...BUT THE MTNS WILL LIKELY EVENTUALLY
DESTABILIZE AND WITH SWLY UPSLOPE FLOW THEY WILL STILL SEE THE
HIGHEST CHANCES BY MID AFTN.

TONIGHT SOME ISENTROPIC LIFT IS NOTED ON 305K SURFACE FROM
NAM/GFS...PERHAPS DUE TO WEAK WAA AS THE UPPER TROUGH SHIFTS SLOWLY
EASTWARD. OTHERWISE THE PATTERN REMAINS ABOUT THE SAME...STILL
SUPPORTIVE OF SOME NOCTURNAL CONVECTION...SO I HAVE KEPT SCT SHOWERS
OVERNIGHT IN THE MTNS/FOOTHILLS AND ISOLD IN THE PIEDMONT. LOWS
TONIGHT MAY BE A TAD WARMER WITH SLIGHTLY HIGHER THICKNESSES.

SHEAR WILL BE WEAK ENOUGH TO PRECLUDE MOST SEVERE WEATHER...BUT
GIVEN THE INSTABILITY WOULD NOT BE SURPRISED TO SEE A COUPLE STORMS
PRODUCE STRONG TO SEVERE WINDS. VERY SLOW CORFIDI VECTORS INDICATE
HEAVY RAIN AND FLASH FLOODING STILL A THREAT.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 220 AM SUN...A WEAK UPPER TROF REMAINS OVER THE AREA MONDAY
WITH THE TROF AXIS SHIFTING OFF SHORE TUE WITH NWLY FLOW DEVELOPING
WED. AT THE SFC...A LEE TROF REMAINS OVER THE AREA MONDAY KEEPING A
MOIST S TO SWLY LOW LEVEL FLOW IN PLACE. A WEAK COLD FRONT JUMPS
INTO THE TROF TUE AND SLIDES OFF SHORE TUE NITE AND WED. WITH DEEP
MOISTURE IN PLACE MON...MODERATE INSTABILITY DEVELOPS LEADING TO
ANOTHER DAY OF CONVECTION FAVORING THE MTNS WITH ONLY SLIGHTLY LOWER
CHC ELSEWHERE. LOW LEVEL FLOW BECOMES WLY TUE AS THE FRONT JUMPS
INTO THE LEE TROF. HOWEVER...ENUF LOW LEVEL MOISTURE REMAINS TO
PRODUCE SCT CONVECTION WITH THE DEVELOPING MODERATE INSTABILITY.
CONVECTION SHUD QUICKLY DIMINISH TUE NITE WITH LOSS OF HEATING.
WITH DRIER HIGH PRESSURE MOVING IN WED...EXPECT ONLY CLOUDS WITH THE
LINGERING LOW LEVEL MOISTURE. HIGHS WILL BE STEADY NEAR OR A LITTLE
ABOVE NORMAL MON AND TUE...THEN DROP TO SLIGHTLY BELOW NORMAL WED.
LOWS ABOUT 5 DEGREES ABOVE NORMAL MON NITE DROP TO NEAR NORMAL TUE
NITE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 315 AM SUN...THE MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT
THRU THE PERIOD. A SERIES OF SHORT WAVES DROP THRU THE NWLY FLOW
OVER THE AREA. THIS CAUSES A KINK IN THE FLOW CREATING A WEAK TROF
OVER THE SERN US BY FRI WHICH STRENGTHENS ON SAT. DRY HIGH PRESSURE
STARTS OVER THE AREA THU. THERE IS SOME LINGERING LOW LEVEL MOISTURE
AND WEAK ELY LOW LEVEL FLOW. HOWEVER...EXPECT ONLY CLOUDS TO DEVELOP
DURING THE DAY. A WEAK BACK DOOR COLD FRONT DROPS INTO THE AREA FRI
WHICH COULD HELP PRODUCE ISOLATED DIURNAL CONVECTION. SCT DIURNAL
CONVECTION EXPECTED SAT AS LOW LEVEL FLOW BECOMES SLY BRINGING
BETTER MOISTURE AND INSTABILITY BACK INTO THE AREA. HIGHS START NEAR
NORMAL AND FALL A LITTLE BELOW BY SAT. LOWS START OUT A LITTLE BELOW
NORMAL AND RISE TO NEAR NORMAL.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AT KCLT...SMALL POSSIBILITY OF A LOW CIG SETTLING IN AROUND DAYBREAK
AND KEEPING A RESTRICTION AFTER 12Z...BUT PRETTY CONFIDENT IN VFR TO
START THE TAF. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY AND
HAVE THEM IN A TEMPO IN THE EARLY TO MID AFTN...AND A VCSH
SURROUNDING TO REFLECT A LOWER PROBABILITY SURROUNDING THIS PERIOD.
FOLLOWING THE END OF THE DIURNAL CONVECTION VFR WILL PREVAIL...BUT
GUIDANCE SUGGESTS SOME FOG POSSIBLE LATE TONIGHT ONCE AGAIN. THIS IS
ESPECIALLY LIKELY IF THE FIELD IS HIT BY A SHOWER OR TSTM TODAY.

ELSEWHERE...EARLY MORNING DENSE FOG AND LIFR TO VLIFR CLOUD BASES
EXPECTED ACROSS THE MTNS TO THE WESTERN PIEDMONT EARLY THIS MORNING.
CLIMO INDICATES THAT CONDITIONS MAY NOT IMPROVE TO VFR UNTIL 14Z.
SOME CONVECTION MAY MOVE INTO THE MTNS FROM THE WEST EARLY TODAY
THOUGH CURRENT TRENDS SUGGEST LITTLE DIRECT THREAT TO KAVL OR ANY
OTHER TAF SITE. HOWEVER DIURNAL INSTABILITY WILL GROW QUICKLY ONCE
THE LOW CIGS BURN OFF. KAVL AND THE MTNS WILL LIKELY SEE SHRA/TSRA
THIS AFTN. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY AND WILL
KEEP TEMPOS DURING THE AFTERNOON AS WELL AS A VCSH/VCTS AS NECESSARY
TO INDICATE LESSER PROBABILITY IN THE SURROUNDING TIMEFRAME. FLOW
REMAINS GENERALLY SOUTHWESTERLY /EXCEPT NW IN UP-VALLEY FLOW AT
KAVL/ INTO TONIGHT. WITH LITTLE CHANGE IN THE PATTERN...A SIMILAR
NIGHT IS LIKELY TO UNFOLD TONIGHT...THOUGH RESTRICTIONS WILL MAINLY
COME FROM FOG. SITES AFFECTED BY TSRA/SHRA TODAY ARE MOST LIKELY TO
GO DOWN TONIGHT...BUT IN GENERAL MOST SITES HAVE A GOOD SHOT AT
SEEING AT LEAST MVFR VSBY BEFORE DAYBREAK.

OUTLOOK...DIURNALLY DRIVEN ISOLD TO SCT CONVECTION EXPECTED AGAIN
MONDAY. DAYBREAK FOG WILL BE MOST LIKELY IN MOUNTAIN VALLEYS AND
WHERE RAIN FELL THE DAY BEFORE. A COLD FRONT WILL CROSS THE AREA ON
TUESDAY...BUT CONVECTIVE CHANCES ARE UNCERTAIN AT THIS TIME. DRIER
AIR WILL FOLLOW THE FRONT.

CONFIDENCE TABLE...

            11-17Z        17-23Z        23-05Z        05-11Z
KCLT       HIGH  94%     HIGH 100%     HIGH 100%     HIGH  94%
KGSP       HIGH  83%     HIGH 100%     HIGH 100%     HIGH  94%
KAVL       LOW   59%     HIGH 100%     HIGH  97%     MED   77%
KHKY       MED   78%     HIGH 100%     HIGH  88%     HIGH  94%
KGMU       MED   79%     HIGH 100%     HIGH 100%     HIGH  91%
KAND       MED   75%     HIGH 100%     HIGH 100%     HIGH  86%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...RWH
NEAR TERM...WIMBERLEY
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...NED/WIMBERLEY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 741 AM EDT SUN SEP 1 2013

.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE AREA AS WEAK HIGH
PRESSURE SLOWLY SLIDES OFFSHORE TODAY. THIS MOIST FLOW WILL HELP TO
KICK OFF SHOWERS AND THUNDERSTORMS THROUGH LABOR DAY. A COLD FRONT
CROSSES THE AREA TUESDAY WITH DRY HIGH PRESSURE RETURNING ON
WEDNESDAY. MOISTURE AND SCATTERED THUNDERSTORMS RETURN BY NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
5 AM UPDATE...SHRA/TSRA MOVING INTO THE SW MTNS ARE HAVING TROUBLE
PUSHING FURTHER EAST...BUT WEAK UPSLOPE FLOW AND CONTINUING ELEVATED
INSTBY MAY ALLOW SOME MORE DEVELOPMENT THERE. HRRR AND RAP BRING
SOME ACTIVITY FROM DECAYING TENN VALLEY MCS ACRS THE NC BORDER JUST
AFTER DAYBREAK. IT IS LOOKING LESS AND LESS ORGANIZED...SO DON/T
HAVE A LOT OF CONFIDENCE THAT WILL HAPPEN...BUT FELT IT WAS A GOOD
IDEA TO RAISE POPS SLIGHTLY NEAR THE BORDER EARLY THIS MRNG.

AS OF EARLY SUNDAY MORNING...WESTERLY FLOW INTO THE MTNS IS MAKING
THE MOST OF THE FEW HUNDRED JOULES OF MUCAPE STILL PRESENT OVER EAST
TN...ALLOWING A FEW CELLS TO FIRE UP THERE AS OF 315 AM. THOUGH THE
INSTABILITY WILL LIKELY WANE SOMEWHAT THRU DAYBREAK...GIVEN THE
CONTINUED WLY LLVL WINDS HAVE KEPT ISOLD PRECIP MENTION NEAR THE
TENN BORDER INTO THE MORNING. THE REMAINING PRECIP SHIELD FROM AN
MCS WHICH MOVED THRU THE CUMBERLAND PLATEAU EARLIER IS MOVING TOWARD
THE NC BORDER...BUT THIS MAY DISSOLVE BEFORE IT GETS TO OUR CWFA.
ALSO NOTING A SECOND MCS OVER KY ON RADAR. STORM MOTION /FWD-PROP
CORFIDI VECTOR/ FROM 00Z NASHVILLE SOUNDING SUGGESTS THIS WILL MOVE
WEST OF OUR AREA...AND THIS IS BACKED UP BY 00Z SPC WRF. ON
ANOTHER NOTE...LOW CLOUDS AND FOG NOW WIDESPREAD IN THE MTNS AND
SPOTTY IN THE FOOTHILLS MAY WORSEN A BIT TOWARD DAYBREAK THOUGH WITH
TEMPS NEARLY STEADY I THINK VSBY NOT GET TOO MUCH WORSE. IF DENSE
FOG SETTLES INTO A LARGE CONTIGUOUS AREA A DENSE FOG ADVY MAY BE
NEEDED.

STILL EXPECTING A RELATIVELY SIMILAR SITUATION TODAY COMPARED TO
YESTERDAY. THE CWFA REMAINS UNDER CYCLONIC UPPER FLOW WITH A FEW
EMBEDDED EDDIES POTENTIALLY HELPING TO DRIVE CONVECTION. REGARDING
THAT CONVECTION...NAM/GFS REMARKABLY DIFFERENT IN CAPE PROGS FOR
TODAY...WITH THE GFS FEATURING SUSPICIOUSLY HIGH VALUES IN THE
MTNS...ABOVE 4000 J/KG AT MIDDAY. NAM SEEMS TO REFLECT THE DELAYED
WARMING DUE TO THE LOW CLOUDS IN THE MTNS...RAMPING UP INSTABILITY
FIRST IN THE PIEDMONT AND KEEPING THE HIGHEST VALUES THERE OVERALL.
THIS ALSO INDICATED BY SREF PROBS. THIS IS PLAUSIBLE SO I BROUGHT
POPS UP THERE FIRST...BUT THE MTNS WILL LIKELY EVENTUALLY
DESTABILIZE AND WITH SWLY UPSLOPE FLOW THEY WILL STILL SEE THE
HIGHEST CHANCES BY MID AFTN.

TONIGHT SOME ISENTROPIC LIFT IS NOTED ON 305K SURFACE FROM
NAM/GFS...PERHAPS DUE TO WEAK WAA AS THE UPPER TROUGH SHIFTS SLOWLY
EASTWARD. OTHERWISE THE PATTERN REMAINS ABOUT THE SAME...STILL
SUPPORTIVE OF SOME NOCTURNAL CONVECTION...SO I HAVE KEPT SCT SHOWERS
OVERNIGHT IN THE MTNS/FOOTHILLS AND ISOLD IN THE PIEDMONT. LOWS
TONIGHT MAY BE A TAD WARMER WITH SLIGHTLY HIGHER THICKNESSES.

SHEAR WILL BE WEAK ENOUGH TO PRECLUDE MOST SEVERE WEATHER...BUT
GIVEN THE INSTABILITY WOULD NOT BE SURPRISED TO SEE A COUPLE STORMS
PRODUCE STRONG TO SEVERE WINDS. VERY SLOW CORFIDI VECTORS INDICATE
HEAVY RAIN AND FLASH FLOODING STILL A THREAT.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 220 AM SUN...A WEAK UPPER TROF REMAINS OVER THE AREA MONDAY
WITH THE TROF AXIS SHIFTING OFF SHORE TUE WITH NWLY FLOW DEVELOPING
WED. AT THE SFC...A LEE TROF REMAINS OVER THE AREA MONDAY KEEPING A
MOIST S TO SWLY LOW LEVEL FLOW IN PLACE. A WEAK COLD FRONT JUMPS
INTO THE TROF TUE AND SLIDES OFF SHORE TUE NITE AND WED. WITH DEEP
MOISTURE IN PLACE MON...MODERATE INSTABILITY DEVELOPS LEADING TO
ANOTHER DAY OF CONVECTION FAVORING THE MTNS WITH ONLY SLIGHTLY LOWER
CHC ELSEWHERE. LOW LEVEL FLOW BECOMES WLY TUE AS THE FRONT JUMPS
INTO THE LEE TROF. HOWEVER...ENUF LOW LEVEL MOISTURE REMAINS TO
PRODUCE SCT CONVECTION WITH THE DEVELOPING MODERATE INSTABILITY.
CONVECTION SHUD QUICKLY DIMINISH TUE NITE WITH LOSS OF HEATING.
WITH DRIER HIGH PRESSURE MOVING IN WED...EXPECT ONLY CLOUDS WITH THE
LINGERING LOW LEVEL MOISTURE. HIGHS WILL BE STEADY NEAR OR A LITTLE
ABOVE NORMAL MON AND TUE...THEN DROP TO SLIGHTLY BELOW NORMAL WED.
LOWS ABOUT 5 DEGREES ABOVE NORMAL MON NITE DROP TO NEAR NORMAL TUE
NITE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 315 AM SUN...THE MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT
THRU THE PERIOD. A SERIES OF SHORT WAVES DROP THRU THE NWLY FLOW
OVER THE AREA. THIS CAUSES A KINK IN THE FLOW CREATING A WEAK TROF
OVER THE SERN US BY FRI WHICH STRENGTHENS ON SAT. DRY HIGH PRESSURE
STARTS OVER THE AREA THU. THERE IS SOME LINGERING LOW LEVEL MOISTURE
AND WEAK ELY LOW LEVEL FLOW. HOWEVER...EXPECT ONLY CLOUDS TO DEVELOP
DURING THE DAY. A WEAK BACK DOOR COLD FRONT DROPS INTO THE AREA FRI
WHICH COULD HELP PRODUCE ISOLATED DIURNAL CONVECTION. SCT DIURNAL
CONVECTION EXPECTED SAT AS LOW LEVEL FLOW BECOMES SLY BRINGING
BETTER MOISTURE AND INSTABILITY BACK INTO THE AREA. HIGHS START NEAR
NORMAL AND FALL A LITTLE BELOW BY SAT. LOWS START OUT A LITTLE BELOW
NORMAL AND RISE TO NEAR NORMAL.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AT KCLT...SMALL POSSIBILITY OF A LOW CIG SETTLING IN AROUND DAYBREAK
AND KEEPING A RESTRICTION AFTER 12Z...BUT PRETTY CONFIDENT IN VFR TO
START THE TAF. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY AND
HAVE THEM IN A TEMPO IN THE EARLY TO MID AFTN...AND A VCSH
SURROUNDING TO REFLECT A LOWER PROBABILITY SURROUNDING THIS PERIOD.
FOLLOWING THE END OF THE DIURNAL CONVECTION VFR WILL PREVAIL...BUT
GUIDANCE SUGGESTS SOME FOG POSSIBLE LATE TONIGHT ONCE AGAIN. THIS IS
ESPECIALLY LIKELY IF THE FIELD IS HIT BY A SHOWER OR TSTM TODAY.

ELSEWHERE...SOME CONVECTION MAY MOVE INTO THE MTNS FROM THE WEST
EARLY TODAY THOUGH CURRENT TRENDS SUGGEST LITTLE DIRECT THREAT TO
KAVL OR ANY OTHER TAF SITE. HOWEVER DIURNAL INSTABILITY WILL GROW
QUICKLY ONCE THE LOW CIGS BURN OFF. KAVL AND THE MTNS WILL LIKELY
SEE SHRA/TSRA THIS AFTN. THUNDER CHANCES A BIT HIGHER TODAY VS
YESTERDAY AND WILL KEEP TEMPOS DURING THE AFTERNOON AS WELL AS A
VCSH/VCTS AS NECESSARY TO INDICATE LESSER PROBABILITY IN THE
SURROUNDING TIMEFRAME. FLOW REMAINS GENERALLY SOUTHWESTERLY /EXCEPT
NW IN UP-VALLEY FLOW AT KAVL/ INTO TONIGHT. WITH LITTLE CHANGE IN
THE PATTERN...A SIMILAR NIGHT IS LIKELY TO UNFOLD TONIGHT...THOUGH
RESTRICTIONS WILL MAINLY COME FROM FOG. SITES AFFECTED BY TSRA/SHRA
TODAY ARE MOST LIKELY TO GO DOWN TONIGHT...BUT IN GENERAL MOST SITES
HAVE A GOOD SHOT AT SEEING AT LEAST MVFR VSBY BEFORE DAYBREAK.

OUTLOOK...DIURNALLY DRIVEN ISOLD TO SCT CONVECTION EXPECTED AGAIN
MONDAY. DAYBREAK FOG WILL BE MOST LIKELY IN MOUNTAIN VALLEYS AND
WHERE RAIN FELL THE DAY BEFORE. A COLD FRONT WILL CROSS THE AREA ON
TUESDAY...BUT CONVECTIVE CHANCES ARE UNCERTAIN AT THIS TIME. DRIER
AIR WILL FOLLOW THE FRONT.

CONFIDENCE TABLE...

            11-17Z        17-23Z        23-05Z        05-11Z
KCLT       HIGH  94%     HIGH 100%     HIGH 100%     HIGH  94%
KGSP       HIGH  83%     HIGH 100%     HIGH 100%     HIGH  94%
KAVL       LOW   59%     HIGH 100%     HIGH  97%     MED   77%
KHKY       MED   78%     HIGH 100%     HIGH  88%     HIGH  94%
KGMU       MED   79%     HIGH 100%     HIGH 100%     HIGH  91%
KAND       MED   75%     HIGH 100%     HIGH 100%     HIGH  86%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...RWH
NEAR TERM...WIMBERLEY
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...NED/WIMBERLEY







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 518 AM EDT SUN SEP 1 2013

.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE AREA AS WEAK HIGH
PRESSURE SLOWLY SLIDES OFFSHORE TODAY. THIS MOIST FLOW WILL HELP TO
KICK OFF SHOWERS AND THUNDERSTORMS THROUGH LABOR DAY. A COLD FRONT
CROSSES THE AREA TUESDAY WITH DRY HIGH PRESSURE RETURNING ON
WEDNESDAY. MOISTURE AND SCATTERED THUNDERSTORMS RETURN BY NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
5 AM UPDATE...SHRA/TSRA MOVING INTO THE SW MTNS ARE HAVING TROUBLE
PUSHING FURTHER EAST...BUT WEAK UPSLOPE FLOW AND CONTINUING ELEVATED
INSTBY MAY ALLOW SOME MORE DEVELOPMENT THERE. HRRR AND RAP BRING
SOME ACTIVITY FROM DECAYING TENN VALLEY MCS ACRS THE NC BORDER JUST
AFTER DAYBREAK. IT IS LOOKING LESS AND LESS ORGANIZED...SO DON/T
HAVE A LOT OF CONFIDENCE THAT WILL HAPPEN...BUT FELT IT WAS A GOOD
IDEA TO RAISE POPS SLIGHTLY NEAR THE BORDER EARLY THIS MRNG.

AS OF EARLY SUNDAY MORNING...WESTERLY FLOW INTO THE MTNS IS MAKING
THE MOST OF THE FEW HUNDRED JOULES OF MUCAPE STILL PRESENT OVER EAST
TN...ALLOWING A FEW CELLS TO FIRE UP THERE AS OF 315 AM. THOUGH THE
INSTABILITY WILL LIKELY WANE SOMEWHAT THRU DAYBREAK...GIVEN THE
CONTINUED WLY LLVL WINDS HAVE KEPT ISOLD PRECIP MENTION NEAR THE
TENN BORDER INTO THE MORNING. THE REMAINING PRECIP SHIELD FROM AN
MCS WHICH MOVED THRU THE CUMBERLAND PLATEAU EARLIER IS MOVING TOWARD
THE NC BORDER...BUT THIS MAY DISSOLVE BEFORE IT GETS TO OUR CWFA.
ALSO NOTING A SECOND MCS OVER KY ON RADAR. STORM MOTION /FWD-PROP
CORFIDI VECTOR/ FROM 00Z NASHVILLE SOUNDING SUGGESTS THIS WILL MOVE
WEST OF OUR AREA...AND THIS IS BACKED UP BY 00Z SPC WRF. ON
ANOTHER NOTE...LOW CLOUDS AND FOG NOW WIDESPREAD IN THE MTNS AND
SPOTTY IN THE FOOTHILLS MAY WORSEN A BIT TOWARD DAYBREAK THOUGH WITH
TEMPS NEARLY STEADY I THINK VSBY NOT GET TOO MUCH WORSE. IF DENSE
FOG SETTLES INTO A LARGE CONTIGUOUS AREA A DENSE FOG ADVY MAY BE
NEEDED.

STILL EXPECTING A RELATIVELY SIMILAR SITUATION TODAY COMPARED TO
YESTERDAY. THE CWFA REMAINS UNDER CYCLONIC UPPER FLOW WITH A FEW
EMBEDDED EDDIES POTENTIALLY HELPING TO DRIVE CONVECTION. REGARDING
THAT CONVECTION...NAM/GFS REMARKABLY DIFFERENT IN CAPE PROGS FOR
TODAY...WITH THE GFS FEATURING SUSPICIOUSLY HIGH VALUES IN THE
MTNS...ABOVE 4000 J/KG AT MIDDAY. NAM SEEMS TO REFLECT THE DELAYED
WARMING DUE TO THE LOW CLOUDS IN THE MTNS...RAMPING UP INSTABILITY
FIRST IN THE PIEDMONT AND KEEPING THE HIGHEST VALUES THERE OVERALL.
THIS ALSO INDICATED BY SREF PROBS. THIS IS PLAUSIBLE SO I BROUGHT
POPS UP THERE FIRST...BUT THE MTNS WILL LIKELY EVENTUALLY
DESTABILIZE AND WITH SWLY UPSLOPE FLOW THEY WILL STILL SEE THE
HIGHEST CHANCES BY MID AFTN.

TONIGHT SOME ISENTROPIC LIFT IS NOTED ON 305K SURFACE FROM
NAM/GFS...PERHAPS DUE TO WEAK WAA AS THE UPPER TROUGH SHIFTS SLOWLY
EASTWARD. OTHERWISE THE PATTERN REMAINS ABOUT THE SAME...STILL
SUPPORTIVE OF SOME NOCTURNAL CONVECTION...SO I HAVE KEPT SCT SHOWERS
OVERNIGHT IN THE MTNS/FOOTHILLS AND ISOLD IN THE PIEDMONT. LOWS
TONIGHT MAY BE A TAD WARMER WITH SLIGHTLY HIGHER THICKNESSES.

SHEAR WILL BE WEAK ENOUGH TO PRECLUDE MOST SEVERE WEATHER...BUT
GIVEN THE INSTABILITY WOULD NOT BE SURPRISED TO SEE A COUPLE STORMS
PRODUCE STRONG TO SEVERE WINDS. VERY SLOW CORFIDI VECTORS INDICATE
HEAVY RAIN AND FLASH FLOODING STILL A THREAT.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 220 AM SUN...A WEAK UPPER TROF REMAINS OVER THE AREA MONDAY
WITH THE TROF AXIS SHIFTING OFF SHORE TUE WITH NWLY FLOW DEVELOPING
WED. AT THE SFC...A LEE TROF REMAINS OVER THE AREA MONDAY KEEPING A
MOIST S TO SWLY LOW LEVEL FLOW IN PLACE. A WEAK COLD FRONT JUMPS
INTO THE TROF TUE AND SLIDES OFF SHORE TUE NITE AND WED. WITH DEEP
MOISTURE IN PLACE MON...MODERATE INSTABILITY DEVELOPS LEADING TO
ANOTHER DAY OF CONVECTION FAVORING THE MTNS WITH ONLY SLIGHTLY LOWER
CHC ELSEWHERE. LOW LEVEL FLOW BECOMES WLY TUE AS THE FRONT JUMPS
INTO THE LEE TROF. HOWEVER...ENUF LOW LEVEL MOISTURE REMAINS TO
PRODUCE SCT CONVECTION WITH THE DEVELOPING MODERATE INSTABILITY.
CONVECTION SHUD QUICKLY DIMINISH TUE NITE WITH LOSS OF HEATING.
WITH DRIER HIGH PRESSURE MOVING IN WED...EXPECT ONLY CLOUDS WITH THE
LINGERING LOW LEVEL MOISTURE. HIGHS WILL BE STEADY NEAR OR A LITTLE
ABOVE NORMAL MON AND TUE...THEN DROP TO SLIGHTLY BELOW NORMAL WED.
LOWS ABOUT 5 DEGREES ABOVE NORMAL MON NITE DROP TO NEAR NORMAL TUE
NITE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
AS OF 315 AM SUN...THE MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT
THRU THE PERIOD. A SERIES OF SHORT WAVES DROP THRU THE NWLY FLOW
OVER THE AREA. THIS CAUSES A KINK IN THE FLOW CREATING A WEAK TROF
OVER THE SERN US BY FRI WHICH STRENGTHENS ON SAT. DRY HIGH PRESSURE
STARTS OVER THE AREA THU. THERE IS SOME LINGERING LOW LEVEL MOISTURE
AND WEAK ELY LOW LEVEL FLOW. HOWEVER...EXPECT ONLY CLOUDS TO DEVELOP
DURING THE DAY. A WEAK BACK DOOR COLD FRONT DROPS INTO THE AREA FRI
WHICH COULD HELP PRODUCE ISOLATED DIURNAL CONVECTION. SCT DIURNAL
CONVECTION EXPECTED SAT AS LOW LEVEL FLOW BECOMES SLY BRINGING
BETTER MOISTURE AND INSTABILITY BACK INTO THE AREA. HIGHS START NEAR
NORMAL AND FALL A LITTLE BELOW BY SAT. LOWS START OUT A LITTLE BELOW
NORMAL AND RISE TO NEAR NORMAL.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
AT KCLT /09Z UPDATE/...SPOTTY MVFR TO IFR FOG ACCOMPANIED BY LOW
CIGS OBSERVED NEARBY...BUT SO FAR THE FIELD HAS AVOIDED ANY
RESTRICTIONS. MOST RELIABLE NEAR TERM GUIDANCE /08Z LAMP/ TAKES KCLT
DOWN TO MVFR NEAR DAYBREAK. I THINK ALL IT WILL TAKE TO GET MVFR FOG
IS A TINY DROP IN TEMPS...BUT THAT MAY NOT OCCUR SO JUST PUT MVFR IN
TEMPO. A GREATER RISK IS FOR SOME LOW CIGS TO DRIFT IN...SO WILL
KEEP MONITORING. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY AND
WILL KEEP A PROB30 DURING THE AFTERNOON...AND A VCSH SURROUNDING TO
REFLECT A LOWER PROBABILITY SURROUNDING THIS PERIOD. FOLLOWING THE
END OF THE DIURNAL CONVECTION GUIDANCE SUPPORTS VFR FCST THRU 06Z
WITH MAINLY MID CLOUDS. WINDS WILL REMAIN LIGHT SW THRU THE PERIOD.

ELSEWHERE...SOME CONVECTION MAY MOVE INTO THE MTNS FROM THE WEST
EARLY TODAY THOUGH CURRENT TRENDS SUGGEST LITTLE THREAT TO KAVL OR
ANY OTHER TAF SITE. MOIST CONDITIONS AND IN SOME CASES WET SOILS
FROM SAT AFTN RAIN HAS ALREADY ALLOWED MVFR TO IFR FOG ACRS MUCH OF
THE AREA. SOME LOWERING STILL POSSIBLE THOUGH CIRRUS DEBRIS MOVING
OVERHEAD WILL BE A MITIGATING FACTOR IN FOG/CIGS...AND INDEED A FEW
SITES HAVE IMPROVED SLIGHTLY UNDER THE CIRRUS. LIFR AT KAVL AND IN
OTHER MTN VALLEYS. THUNDER CHANCES A BIT HIGHER TODAY VS YESTERDAY
AND WILL KEEP A PROB30 DURING THE AFTERNOON AS WELL AS A VCSH/VCTS
AS NECESSARY TO INDICATE LESSER PROBABILITY INTO THE EVENING. FLOW
REMAINS GENERALLY SOUTHWESTERLY /EXCEPT NW IN UP-VALLEY FLOW AT
KAVL/ INTO TONIGHT. WITH LITTLE CHANGE IN THE PATTERN...A SIMILAR
NIGHT IS LIKELY TO UNFOLD TONIGHT...THOUGH VFR IS EXPECTED THRU 06Z
EXCEPT FOR MVFR FOG DEVELOPING PRIOR TO THEN AT KAVL.

OUTLOOK...DIURNALLY DRIVEN ISOLD TO SCT CONVECTION EXPECTED AGAIN
MONDAY. DAYBREAK FOG WILL BE MOST LIKELY IN MOUNTAIN VALLEYS AND
WHERE RAIN FELL THE DAY BEFORE. A COLD FRONT WILL CROSS THE AREA ON
TUESDAY...BUT CONVECTIVE CHANCES ARE UNCERTAIN AT THIS TIME. DRIER
AIR WILL FOLLOW THE FRONT.

CONFIDENCE TABLE...

            09-15Z        15-21Z        21-03Z        03-09Z
KCLT       MED   77%     HIGH  85%     HIGH 100%     HIGH 100%
KGSP       HIGH  80%     MED   78%     HIGH 100%     HIGH 100%
KAVL       MED   65%     HIGH  85%     HIGH 100%     HIGH 100%
KHKY       HIGH  86%     MED   64%     HIGH 100%     HIGH 100%
KGMU       MED   76%     MED   78%     HIGH 100%     HIGH 100%
KAND       MED   72%     HIGH  85%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...RWH
NEAR TERM...WIMBERLEY
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...WIMBERLEY







AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 1025 PM CDT MON SEP 2 2013

.UPDATE...
ISSUED AT 928 PM CDT MON SEP 2 2013

UPDATED FORECAST THIS EVENING TO REMOVE MENTION OF FOG FROM THE
FORECAST. AFTER TWO DAYS OF MIXING OUT RECENT RAINFALL... FORECAST
SOUNDINGS SUGGEST IT MAY BE DIFFICULT TO GET ENOUGH MOISTURE
POOLING NEAR THE SURFACE TO RESULT IN RADIATIONAL FOG DEVELOPMENT.
FORECASTED VISIBILITY IN BOTH HRRR AND RAP MODELS AS WELL AS LAV
GUIDANCE DO NOT SUGGEST FOG WITHIN THE FORECAST AREA WITH THE MAIN
AXIS FURTHER TO THE EAST...SO WENT AHEAD AND REMOVED MENTION.
OTHERWISE FORECAST ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 257 PM CDT MON SEP 2 2013

AFTERNOON SURFACE ANALYSIS SHOWS HIGH PRESSURE IN PLACE ACROSS THE
TRI-STATE AREA WITH LIGHT WINDS. A VERY DRY AIRMASS REMAINS IN PLACE
ACROSS THE CENTRAL CONUS AS SEEN ON THE WATER VAPOR IMAGERY AND
EVIDENT ALSO BY DROPPING SURFACE DEWPOINTS. THIS DRY AIRMASS
COMBINED WITH LIGHT WINDS SETS UP ANOTHER GOOD NIGHT FOR RADIATIONAL
COOLING EAST OF I 29 AS HIGH PRESSURE SHIFTS EAST TOWARD THE GREAT
LAKES TONIGHT. LOW LYING RIVER VALLEY AREAS COULD SEE SOME SHALLOW
RADIATIONAL FOG ONCE AGAIN AND HAVE INTRODUCED PATCHY FOG IN THE
FORECAST. WEST OF I 29...COOLING WILL NOT BE QUITE AS GREAT AS
RETURN FLOW BEGINS TO SET IN LATE. WILL PROBABLY SEE EARLY LOWS IN
SOUTH CENTRAL SD THEN STEADY OR RISING IN THE EARLY MORNING. BIG
DIURNAL SWING ON TAP THEN FOR TUESDAY WITH STRONG WARM AIR ADVECTION
AHEAD OF APPROACHING VORT MAX. H85 TEMPS CLIMB TO AROUND 20 C BY 00Z
WEDNESDAY WITH HIGHS EXPECTED TO BE IN THE MID 80S TO LOW 90S. HEAT
INDICES WILL REMAIN IN CHECK HOWEVER AS AFTERNOON DEWPOINTS WILL BE
IN THE MID 50S TO AROUND 60. INCREASE IN MID LEVEL CLOUDS FROM THE
WEST IS ALSO EXPECTED FROM THUNDERSTORM DEVELOPMENT IN WESTERN SOUTH
DAKOTA IN THE AFTERNOON TUESDAY.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 257 PM CDT MON SEP 2 2013

THE MAIN WEATHER FEATURE TUESDAY NIGHT AND WEDNESDAY CONTINUES TO
BE A WEAK SHORT WAVE MOVING OVER THE UPPER RIDGE. THIS SHORT WAVE
INTERACTS WITH A MODEST LOW LEVEL JET AND THETAE ADVECTION.
INSTABILITY IS NOT REAL STRONG WITH THIS SYSTEM...BUT IT ALSO IS
NOT VERY CAPPED WITH 700MB TEMPERATURES NOT VERY WARM CONSIDERING
THE DEGREE OF UPPER RIDGING. CURRENTLY THE WAVE IS IN NORTHERN
UTAH AND WESTERN WY. LATEST 12Z MODELS HAVE BACKED OFF ON AMOUNT
OF PRECIPITATION FOR TUESDAY NIGHT AND WEDNESDAY...BUT THEY STILL
EXHIBIT A HIGH DEGREE OF MID AND HIGH LEVEL CLOUDINESS. SO
CERTAINLY DID NOT WANT TO ELIMINATE POPS...NOR RAISE HIGHS FOR
WEDNESDAY. STILL SEEMS PRUDENT TO GO WITH SOME OF THE COOLER
GUIDANCE VALUES FOR HIGHS...SO KEPT READINGS IN THE 80S AND AWAY
FROM THE 90S. WITH THE CURRENT TRACK OF THE SHORT WAVE...IT
APPEARS IT WILL AFFECT AREAS GENERALLY ALONG AND WEST OF I 29...
EXITING OUR SOUTHERN ZONES WEDNESDAY NIGHT.

AS THE UPPER RIDGING TAKES OVER ONCE AGAIN...HEAT WILL RETURN BY
THE END OF THE WEEK AND INTO SATURDAY. RAISED DEW POINT VALUES A
FEW DEGREES OVER CONSENSUS READINGS IN THE FRIDAY THROUGH SUNDAY
TIME FRAME. WITH A SOUTHERLY FLOW...HAVE LIKELY NOT RAISED DEW
POINT VALUES ENOUGH BUT IT IS ALL THE FURTHER WE CAN GO FOR NOW.
LIKEWISE...KEPT LOWS ABOVE CONSENSUS MINIMUM TEMPERATURES THURSDAY
NIGHT AND FRIDAY NIGHT. DID NOT BUY OFF YET ON THE WARM FRONTAL
INDUCED CONVECTION SPARKED BY THE GFS WEST OF I 29 FRIDAY NIGHT.
SO FAR THIS SCENARIO WAS NOT BACKED UP BY THE ECMWF OR GEM GLOBAL.
ONE THING THE MODELS ARE IN BETTER AGREEMENT ON IS THE UPPER
TROUGH PASSAGE ACROSS THE NORTHERN TIER OF STATES VERY LATE THIS
WEEKEND AND EARLY NEXT WEEK. AHEAD OF THIS UPPER TROUGH...IT LOOKS
AS THOUGH A WEAK WIND SHIFT BOUNDARY MAY MOVE THROUGH OUR AREA
SATURDAY NIGHT BEFORE HANGING UP NEAR SIOUX CITY. SO HIGHS MAY BE
A TAD COOLER SUNDAY AND MONDAY...ESPECIALLY ALONG AND NORTH OF THE
I 90 CORRIDOR. CONVECTION CHANCES MAY ALSO BE ON THE INCREASE AS
THE WEEKEND PROGRESSES...AS THE UPPER TROUGH TO THE NORTHWEST OF
OUR AREA BEGINS TO INTERACT WITH THE LOW LEVEL BOUNDARY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1018 PM CDT MON SEP 2 2013

VFR CONDITIONS THROUGH THE TAF PERIOD. LIGHT AND VARIABLE WINDS
OVERNIGHT WILL PICK UP OUT OF THE SOUTHEAST AFTER 14Z ON TUESDAY.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...
SHORT TERM...
LONG TERM...MJ
AVIATION...JM







AREA FORECAST DISCUSSION

NWS SIOUX FALLS SD

 938 PM CDT MON SEP 2 2013

.UPDATE...
ISSUED AT 928 PM CDT MON SEP 2 2013

UPDATED FORECAST THIS EVENING TO REMOVE MENTION OF FOG FROM THE
FORECAST. AFTER TWO DAYS OF MIXING OUT RECENT RAINFALL... FORECAST
SOUNDINGS SUGGEST IT MAY BE DIFFICULT TO GET ENOUGH MOISTURE
POOLING NEAR THE SURFACE TO RESULT IN RADIATIONAL FOG DEVELOPMENT.
FORECASTED VISIBILITY IN BOTH HRRR AND RAP MODELS AS WELL AS LAV
GUIDANCE DO NOT SUGGEST FOG WITHIN THE FORECAST AREA WITH THE MAIN
AXIS FURTHER TO THE EAST...SO WENT AHEAD AND REMOVED MENTION.
OTHERWISE FORECAST ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 257 PM CDT MON SEP 2 2013

AFTERNOON SURFACE ANALYSIS SHOWS HIGH PRESSURE IN PLACE ACROSS THE
TRI-STATE AREA WITH LIGHT WINDS. A VERY DRY AIRMASS REMAINS IN PLACE
ACROSS THE CENTRAL CONUS AS SEEN ON THE WATER VAPOR IMAGERY AND
EVIDENT ALSO BY DROPPING SURFACE DEWPOINTS. THIS DRY AIRMASS
COMBINED WITH LIGHT WINDS SETS UP ANOTHER GOOD NIGHT FOR RADIATIONAL
COOLING EAST OF I 29 AS HIGH PRESSURE SHIFTS EAST TOWARD THE GREAT
LAKES TONIGHT. LOW LYING RIVER VALLEY AREAS COULD SEE SOME SHALLOW
RADIATIONAL FOG ONCE AGAIN AND HAVE INTRODUCED PATCHY FOG IN THE
FORECAST. WEST OF I 29...COOLING WILL NOT BE QUITE AS GREAT AS
RETURN FLOW BEGINS TO SET IN LATE. WILL PROBABLY SEE EARLY LOWS IN
SOUTH CENTRAL SD THEN STEADY OR RISING IN THE EARLY MORNING. BIG
DIURNAL SWING ON TAP THEN FOR TUESDAY WITH STRONG WARM AIR ADVECTION
AHEAD OF APPROACHING VORT MAX. H85 TEMPS CLIMB TO AROUND 20 C BY 00Z
WEDNESDAY WITH HIGHS EXPECTED TO BE IN THE MID 80S TO LOW 90S. HEAT
INDICES WILL REMAIN IN CHECK HOWEVER AS AFTERNOON DEWPOINTS WILL BE
IN THE MID 50S TO AROUND 60. INCREASE IN MID LEVEL CLOUDS FROM THE
WEST IS ALSO EXPECTED FROM THUNDERSTORM DEVELOPMENT IN WESTERN SOUTH
DAKOTA IN THE AFTERNOON TUESDAY.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 257 PM CDT MON SEP 2 2013

THE MAIN WEATHER FEATURE TUESDAY NIGHT AND WEDNESDAY CONTINUES TO
BE A WEAK SHORT WAVE MOVING OVER THE UPPER RIDGE. THIS SHORT WAVE
INTERACTS WITH A MODEST LOW LEVEL JET AND THETAE ADVECTION.
INSTABILITY IS NOT REAL STRONG WITH THIS SYSTEM...BUT IT ALSO IS
NOT VERY CAPPED WITH 700MB TEMPERATURES NOT VERY WARM CONSIDERING
THE DEGREE OF UPPER RIDGING. CURRENTLY THE WAVE IS IN NORTHERN
UTAH AND WESTERN WY. LATEST 12Z MODELS HAVE BACKED OFF ON AMOUNT
OF PRECIPITATION FOR TUESDAY NIGHT AND WEDNESDAY...BUT THEY STILL
EXHIBIT A HIGH DEGREE OF MID AND HIGH LEVEL CLOUDINESS. SO
CERTAINLY DID NOT WANT TO ELIMINATE POPS...NOR RAISE HIGHS FOR
WEDNESDAY. STILL SEEMS PRUDENT TO GO WITH SOME OF THE COOLER
GUIDANCE VALUES FOR HIGHS...SO KEPT READINGS IN THE 80S AND AWAY
FROM THE 90S. WITH THE CURRENT TRACK OF THE SHORT WAVE...IT
APPEARS IT WILL AFFECT AREAS GENERALLY ALONG AND WEST OF I 29...
EXITING OUR SOUTHERN ZONES WEDNESDAY NIGHT.

AS THE UPPER RIDGING TAKES OVER ONCE AGAIN...HEAT WILL RETURN BY
THE END OF THE WEEK AND INTO SATURDAY. RAISED DEW POINT VALUES A
FEW DEGREES OVER CONSENSUS READINGS IN THE FRIDAY THROUGH SUNDAY
TIME FRAME. WITH A SOUTHERLY FLOW...HAVE LIKELY NOT RAISED DEW
POINT VALUES ENOUGH BUT IT IS ALL THE FURTHER WE CAN GO FOR NOW.
LIKEWISE...KEPT LOWS ABOVE CONSENSUS MINIMUM TEMPERATURES THURSDAY
NIGHT AND FRIDAY NIGHT. DID NOT BUY OFF YET ON THE WARM FRONTAL
INDUCED CONVECTION SPARKED BY THE GFS WEST OF I 29 FRIDAY NIGHT.
SO FAR THIS SCENARIO WAS NOT BACKED UP BY THE ECMWF OR GEM GLOBAL.
ONE THING THE MODELS ARE IN BETTER AGREEMENT ON IS THE UPPER
TROUGH PASSAGE ACROSS THE NORTHERN TIER OF STATES VERY LATE THIS
WEEKEND AND EARLY NEXT WEEK. AHEAD OF THIS UPPER TROUGH...IT LOOKS
AS THOUGH A WEAK WIND SHIFT BOUNDARY MAY MOVE THROUGH OUR AREA
SATURDAY NIGHT BEFORE HANGING UP NEAR SIOUX CITY. SO HIGHS MAY BE
A TAD COOLER SUNDAY AND MONDAY...ESPECIALLY ALONG AND NORTH OF THE
I 90 CORRIDOR. CONVECTION CHANCES MAY ALSO BE ON THE INCREASE AS
THE WEEKEND PROGRESSES...AS THE UPPER TROUGH TO THE NORTHWEST OF
OUR AREA BEGINS TO INTERACT WITH THE LOW LEVEL BOUNDARY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 601 PM CDT MON SEP 2 2013

VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. LIGHT AND VARIABLE
WINDS OVERNIGHT WILL PICK UP A BIT OUT OF THE SOUTH/SOUTHEAST ON
TUESDAY MORNING. WITH THE LIGHT WINDS TONIGHT...CANNOT COMPLETELY
RULE OUT PATCHY FOG DEVELOPMENT...THOUGH CONFIDENCE IS TOO LOW TOO
INCLUDE IN TAFS AT THIS TIME.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

UPDATE...
SHORT TERM...
LONG TERM...MJ
AVIATION...JM







AREA FORECAST DISCUSSION

NWS MEMPHIS TN

 814 PM CDT MON SEP 2 2013

.UPDATE...

A COLD FRONT CURRENTLY STRETCHES FROM NEAR HUNTINGDON TENNESSEE TO
NEAR SEARCY ARKANSAS. SHOWER AND THUNDERSTORM ACTIVITY THAT WAS
OCCURRING ALONG AND AHEAD OF THE FRONT HAS DISSIPATED DUE TO THE
LOSS OF DAYTIME HEATING. HOWEVER...DON/T EXPECT THE RADAR SCOPE TO
STAY CLEAR OVERNIGHT. THE LATEST HRRR SHOWS ISOLATED SHRAS/TSRAS
POPPING UP OVERNIGHT SOUTH OF THE FRONT. THUS WILL CONTINUE WITH
SLIGHT CHANCE TO CHANCE POPS AT THIS TIME. MEANWHILE...DRIER AIR
WILL FILTER INTO NORTHERN LOCATIONS OF THE MIDSOUTH OVERNIGHT.
DEWPOINTS ARE IN THE UPPER 50S TO LOWER 60S JUST NORTHWEST OF THE
CWA. CURRENT FORECAST LOOKS GOOD...MAY SEND UPDATE WITH POPS
SHORTLY BEFORE MIDNIGHT REFLECTING CURRENT POSITION OF FRONT.

KRM

&&

.DISCUSSION... /ISSUED 243 PM CDT MON SEP 2 2013/

SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE MIDSOUTH AND
WILL LIKELY INTERRUPT MANY AFTERNOON LABOR DAY PLANS. HOWEVER...I
WOUND NOT CANCEL PLANS ALL TOGETHER...STORMS SHOULD NOT LAST MORE
THAN 30-45 MIN`S. SECURE ANY LAWN FURNITURE...SEEK SHELTER FROM
THE LIGHTNING AND RESUME THE FESTIVITIES AFTER STORMS PASS.

A COLD FRONT IS MOVING INTO THE MIDSOUTH. AT 2:00 PM IT WAS
LOCATED GENERALLY ALONG A LINE FROM PARIS TENNESSEE TO NEAR
INTERSTATE 40 IN EAST CENTRAL ARKANSAS. TO THE SOUTH OF THIS
BOUNDARY...SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY WITH A
DRIER COOLER AIRMASS WORKING INTO TO THE MIDSOUTH TO ITS NORTH AND
WEST. WINDS WILL SHIFT FROM THE NORTH BEHIND THE FRONT...BUT THE
DRIER AIR WILL TAKE SEVERAL MORE HOURS TO ARRIVE. CURRENTLY...DEW
POINTS ARE STILL IN THE LOW 70S ACROSS MOST OF NORTHEAST
ARKANSAS...BUT LOW 60S...EVEN UPPER 50S ARE NOT FAR AWAY IN
CENTRAL AND SOUTHWESTERN MISSOURI.

ONGOING CONVECTION MAINLY ACROSS WEST TENNESSEE...WILL CONTINUE TO
INCREASE IN COVERAGE...AS THEY MOVE TO THE EAST TO SOUTHEAST THIS
AFTERNOON AND TONIGHT. THEY ARE DEVELOPING IN A HIGH
INSTABILITY...LOW SHEAR ENVIRONMENT FEATURING CAPE`S APPROACHING
3000 AND LI`S IN THE -3 TO -6 RANGE. EFFECTIVE BULK SHEAR IS LESS
THAN 25 KTS. NEGATIVE 10C DEGREE LEVELS ARE CURRENTLY AROUND
20-21K FT WITH -20C AROUND 25K FT. THE LIKELIHOOD OF HAIL IS
FAIRLY LOW...BUT CERTAINLY CANNOT BE RULED OUT. THE MAIN THREAT
FROM ANY STRONG OR SEVERE STORMS WILL BE LOCALIZED DAMAGING WIND.
HOWEVER...EVEN THOUGH LIGHTNING IS NOT A SEVERE WEATHER
PARAMETER FOR WARNING PURPOSES...THAT IS TRULY THE MAIN THREAT
FROM THESE STORMS...ESPECIALLY CONSIDERING THE NUMBER OF OUTDOOR
ACTIVITIES ONGOING TODAY. KEEP AN EYE TO THE SKY. STORMS WILL
CONTINUE TONIGHT...BUT LIKELY BECOME CONFINED TO NORTH MISSISSIPPI
BY MIDNIGHT. FLOODING IS ALSO A CONCERN...RAINFALL RATES IN EXCESS
OF 2.5 INCHES PER HOUR AND TRAINING THUNDERSTORMS COULD RESULT IN
LOCALIZED FLOODING PROBLEMS. SEVERAL FLASH FLOOD WARNINGS HAVE
ALREADY BEEN ISSUED IN WEST TENNESSEE AND NORTH MISSISSIPPI.

TOMORROW...THAT COOLER DRIER AIRMASS WILL BE EVIDENT. NEAR NORMAL
TEMPERATURES...OR HIGHS GENERALLY IN THE MIDDLE TO UPPER 80S ARE
EXPECTED...BUT DEW POINTS WILL BE IN THE LOW TO MIDDLE 60S
INSTEAD OF THE LOW 70S RESULTING IN MUCH MORE PLEASANT CONDITIONS.
NO RAINFALL IS EXPECTED TOMORROW TROUGH THE END OF THE FORECAST
PERIOD. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL AS A
RIDGE ALOFT DOMINATES OUR WEATHER PATTERN.

AVIATION...

00Z TAF CYCLE

EVEN THOUGH A WEAK COLD FRONT IS PUSHING INTO THE AREA SHRAS AND
TSRAS WILL CONTINUE TO DISSIPATE WITH LOSS OF SURFACE HEATING. AS A
RESULT EXPECT A QUIET NIGHT WITH MAINLY VFR CONDS. SOME PATCHY FOG
WILL DEVELOP TOWARD MORNING WITH IFR VSBYS POSSIBLE AT KMKL. VFR
CONDS WILL PREVAIL ON TUESDAY WITH NNE WINDS AT 7-10 KTS.

SJM

&&


&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  71  88  68  89 /  30   0  10  10
MKL  64  85  58  86 /  20   0  10  10
JBR  66  86  62  88 /  10   0  10  10
TUP  70  89  66  90 /  40  10  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$








AREA FORECAST DISCUSSION...UPDATED

NWS FORT WORTH TX

 1227 PM CDT SUN SEP 1 2013

.AVIATION...
PRIMARY AVIATION CONCERNS NEXT 24 HOURS INVOLVE TIMING AND
COVERAGE OF CONVECTIVE ACTIVITY NEAR TERMINALS.

EXPECT GENERALLY VFR CONDITIONS TO CONTINUE INTO MONDAY. THERE WILL
BE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EARLY THIS EVENING
ACROSS MOST OF NORTH TEXAS...BUT COVERAGE IS EXPECTED TO REMAIN
VERY LIMITED AND WILL NOT MENTION IN ANY OF THE TAFS AT THIS
TIME.

BETTER CHANCES FOR CONVECTION WILL ARRIVE TONIGHT IN THE
METROPLEX AS A COLD FRONT IN OKLAHOMA CROSSES THE RED RIVER THIS
EVENING AND APPROACHES DFW JUST AFTER MIDNIGHT. SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS ARE EXPECTED TO ACCOMPANY THE
FRONT...AND WILL CARRY VCTS AFTER 08Z /3 AM CDT/ AT DFW AND OTHER
METROPLEX TAF SITES. THE FRONT IS EXPECTED TO STALL ACROSS THE
METROPLEX OR PERHAPS JUST SOUTH OF THE METROPLEX...SO THE
CONVECTIVE CHANCES WILL REMAIN VERY LOW IN THE KACT AREA THROUGH
18Z /100 PM CDT/ MONDAY.

09

&&

.UPDATE...
FORT WORTH SOUNDING SHOWS SLIGHT COOLING DURING THE LAST 24 HOURS IN
THE LOWEST 50MB...SO TEMPS SHOULD BE A DEGREE OR SO COOLER THAN
YESTERDAY. HOWEVER HIGHS WILL ONCE AGAIN REACH THE CENTURY MARK
ACROSS MOST OF NORTH TEXAS TODAY AND DID RAISE THEM A BIT FROM THE
PREVIOUS FORECAST IN A FEW LOCATIONS. THE MORNING SOUNDING ALSO
INDICATED HIGHER PRECIPITABLE WATER WITH NOTABLE
COOLING/MOISTENING OCCURRING IN THE MID LEVELS...SUGGESTING WEAK
UPPER LEVEL LIFT IS NOW SPREADING ACROSS NORTH TEXAS. AS HEATING
OCCURS TODAY WOULD EXPECT ISOLATED CONVECTION TO DEVELOP. HI-RES
AND SHORT-TERM GUIDANCE DOES NOT FAVOR ANY PARTICULAR AREA FOR
THIS POP-UP ACTIVITY...AND THUS WILL MENTION ISOLATED
SHOWERS/STORMS EVERYWHERE THIS AFTERNOON WITH A 10 POP SINCE
COVERAGE WILL BE LOW WITHOUT A SURFACE FOCUSING MECHANISM. A COLD
FRONT WILL ARRIVE INTO THE NORTHERN ZONES AFTER 00Z...AND NORTHERN
AND WESTERN ZONES WILL BE THE FAVORED AREA FOR MORE SIGNIFICANT
RAINFALL COVERAGE TONIGHT.

TR.92

&&

.PREV DISCUSSION... /ISSUED 319 AM CDT SUN SEP 1 2013/
NORTH TEXAS WILL BE UNDERNEATH NORTH-NORTHWEST FLOW THE NEXT FEW
DAYS...AS THE UPPER HIGH WILL BE ANCHORED TO THE WEST WITH AN
ACTIVE LONGWAVE TROUGH FROM THE MID MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES. THE SHORTWAVE THAT PRODUCED ISOLATED STRONG STORMS
ACROSS THE FAR EASTERN COUNTIES SATURDAY WAS MOVING SOUTHWEST
TOWARD THE UPPER TEXAS COAST.

ONE MORE VERY HOT DAY TODAY WITH HIGHS 100-105 DEGREES ACROSS MUCH
OF NORTH TEXAS. CHECK OF RECORDS AT BOTH WACO AND DFW INDICATE
RECORD WILL REMAIN INTACT. CURRENT RECORDS ARE 106 AT WACO AND 109
AT DFW. THE HEAT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM THIS
EVENING. HOWEVER...SOME CHANGES ARE IN STORE FOR THE AREA. A
SHORTWAVE DISTURBANCE ASSOCIATED WITH WEAKENING CONVECTION OVER
SOUTHWEST KANSAS WILL DROP SOUTH ACROSS OKLAHOMA THIS AFTERNOON.
IN ADDITION...OUTFLOW FROM THE DYING KANSAS COMPLEX WILL HELP
SPEED UP THE SOUTHWARD PUSH OF THE COLD FRONT THROUGH OKLAHOMA AND
TOWARD THE RED RIVER VALLEY LATE THIS AFTERNOON AND INTO THIS
EVENING. THE HRRR IS THE FASTEST WITH THE FRONT/OUTFLOW PER
LATEST INDICATIONS... WITH THE NAM NEXT IN LINE AND THE GFS AND
TECH WRF MODELS SLIGHTLY SLOWER. SINCE THIS BOUNDARY IS MESOSCALE
DRIVEN...WILL LEAN MORE TOWARD A FASTER SOLUTION OF THE HRRR/NAM.

SPEED DISCREPANCIES ASIDE...THE FRONT WILL BE ENTERING THE RED
RIVER VALLEY RIGHT AT PEAK HEATING. ISOLATED THUNDERSTORMS WILL
BE POSSIBLE ACROSS THE NORTHERN TIER COUNTIES JUST BEFORE 00Z
LABOR DAY...THEN MORE SCATTERED ACROSS THE NORTHERN COUNTIES IN
THE VICINITY OF THE FRONT IN THE EVENING HOURS. THE 750-500MB RH
INCREASES WITH STEEP LOW LEVEL LAPSE RATES IN THE LOWER LEVELS.
MID LEVEL INSTABILITY IS NOT EXPECTED TO BE EXTREME DUE TO THE
INFLUENCE OF THE EASTERN PERIPHERY OF THE UPPER HIGH. PWAT VALUES
WILL BE NEAR 2 STANDARD DEVIATIONS FOR THIS TIME OF YEAR.
LOCALIZED MICROBURSTS WITH HEAVY DOWNPOURS WILL BE LIKELY WITH
STRONGER ACTIVITY THROUGH NIGHTFALL WITH A WEAKENING TREND AFTER
DARK DUE TO THE LOSS OF DAYTIME HEATING. WE HAVE INTRODUCED A
SLIGHT CHANCE ACROSS THE NORTHERN COUNTIES FOR LATE AFTERNOON AS
THE FRONT ARRIVES INTO THE RED RIVER VALLEY. WITH LIFT FROM THE
SHORTWAVE AND THE FRONT ENTERING AREAS NORTH OF I-20...WE HAVE
RAISED POPS NORTH OF I-20 THIS EVENING WHILE GENERALLY MAINTAINING
BEST CHANCES ACROSS THE WESTERN COUNTIES OVERNIGHT AS A STORM
CLUSTER SHIFTS SOUTH THROUGH A HIGHER INSTABILITY AXIS.

THE WEAK COLD FRONT SHOULD SHIFT SOUTH OF I-20 BY TUESDAY MORNING
WITH INFLUENCE OF STORM-DRIVEN COLD POOL INDICATED BY THE MODELS.
THIS IS WHERE CONFIDENCE WANES WITH UNCERTAINTY ON SUCH MESOSCALE
DRIVEN FEATURES AND WHERE THEY END UP. FOR NOW HAVE MAINTAIN LOW
CONVECTIVE CHANCES FROM THE PREVIOUS FORECAST CONTINGENT ON THE
SOUTH-SOUTHWEST PROGRESSION OF THE SHORTWAVE TOWARD THE HILL
COUNTRY. A COUPLE OF MODELS INDICATE ANOTHER SUBTLE SHORTWAVE
ROTATING AROUND THE UPPER HIGH AND ACROSS CENTRAL AND SOUTHEAST
TEXAS LATER ON TUESDAY. HAVE INTRODUCED LOW POPS ACROSS THE
CENTRAL TEXAS COUNTIES TO ACCOUNT FOR THIS FEATURE. FOR THE LATTER
HALF OF NEXT WEEK...THE UPPER HIGH LOOKS TO EXPAND EAST ACROSS THE
SOUTHERN PLAINS ONCE AGAIN AND WILL KEEP BETTER FORCING OFF TO
SOUTHEAST. BY NEXT WEEKEND... THERE ARE SIGNS OF THE UPPER HIGH
POSSIBLY RETROGRADING WEST AGAIN WITH A WEAK PIECE OF ENERGY
DROPPING SOUTHWEST ACROSS THE SABINE RIVER VALLEY. THIS COULD LEAD
TO LOW RAIN CHANCES ACROSS THE EASTERN HALF OF NORTH TEXAS ONCE
AGAIN BUT WILL LEAVE THE FORECAST DRY WITH LACK OF CONFIDENCE ON
WHERE THIS FEATURE TRACKS.

05/



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 103  79  98  77  98 /  10  30  20  20  10
WACO, TX             102  77 100  75  98 /  10  20  20  20  20
PARIS, TX            101  74  96  71  96 /  10  30  20  10  10
DENTON, TX           103  77  97  72  97 /  10  40  20  10  10
MCKINNEY, TX         102  76  97  73  98 /  10  30  20  10  10
DALLAS, TX           104  80  98  78  99 /  10  30  20  20  10
TERRELL, TX          102  78  98  75  98 /  10  30  20  20  10
CORSICANA, TX        101  77 100  75  98 /  10  20  20  20  10
TEMPLE, TX           100  74  98  74  97 /  10  10  20  20  20
MINERAL WELLS, TX    103  74  95  73  96 /  10  40  30  20  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR TXZ103-104-118-119.


&&

$$






AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 1028 AM CDT SUN SEP 1 2013

.UPDATE...
FORT WORTH SOUNDING SHOWS SLIGHT COOLING DURING THE LAST 24 HOURS IN
THE LOWEST 50MB...SO TEMPS SHOULD BE A DEGREE OR SO COOLER THAN
YESTERDAY. HOWEVER HIGHS WILL ONCE AGAIN REACH THE CENTURY MARK
ACROSS MOST OF NORTH TEXAS TODAY AND DID RAISE THEM A BIT FROM THE
PREVIOUS FORECAST IN A FEW LOCATIONS. THE MORNING SOUNDING ALSO
INDICATED HIGHER PRECIPITABLE WATER WITH NOTABLE
COOLING/MOISTENING OCCURRING IN THE MID LEVELS...SUGGESTING WEAK
UPPER LEVEL LIFT IS NOW SPREADING ACROSS NORTH TEXAS. AS HEATING
OCCURS TODAY WOULD EXPECT ISOLATED CONVECTION TO DEVELOP. HI-RES
AND SHORT-TERM GUIDANCE DOES NOT FAVOR ANY PARTICULAR AREA FOR
THIS POP-UP ACTIVITY...AND THUS WILL MENTION ISOLATED
SHOWERS/STORMS EVERYWHERE THIS AFTERNOON WITH A 10 POP SINCE
COVERAGE WILL BE LOW WITHOUT A SURFACE FOCUSING MECHANISM. A COLD
FRONT WILL ARRIVE INTO THE NORTHERN ZONES AFTER 00Z...AND NORTHERN
AND WESTERN ZONES WILL BE THE FAVORED AREA FOR MORE SIGNIFICANT
RAINFALL COVERAGE TONIGHT.

TR.92

&&

.AVIATION...
CONCERNS...ISOLATED TO SCATTERED CONVECTION TONIGHT.

FOR THIS FORECAST CYCLE...HAVE DECIDED TO KEEP ALL TAFS VFR.
HOWEVER...A CONVECTIVE OUTFLOW BOUNDARY...CURRENTLY MOVING THROUGH
CENTRAL OKLAHOMA...IS A CONCERN FOR THE METROPLEX TERMINALS AS IT IS
EXPECTED TO MOVE SOUTH OF THE RED RIVER LATER THIS AFTERNOON. THIS
BOUNDARY SHOULD BE ABLE TO FIRE ISOLATED TO WIDELY SCATTERED
CONVECTION BETWEEN THE RED RIVER AND I-20 MID-LATE AFTERNOON AND
OVERNIGHT PER LAST SEVERAL HI- RES RUNS AS WELL AS THE GFS AND NAM
SERIES. ERGO...HAVE DECIDED TO ADD A PROB30 0205/0209 FOR THIS
POTENTIAL. ALSO...A WIND SHIFT IS INDICATED FOR THE KDFW EXTENDED
FORECAST AFTER 02/15Z. 75


&&



.PREV DISCUSSION... /ISSUED 319 AM CDT SUN SEP 1 2013/
NORTH TEXAS WILL BE UNDERNEATH NORTH-NORTHWEST FLOW THE NEXT FEW
DAYS...AS THE UPPER HIGH WILL BE ANCHORED TO THE WEST WITH AN
ACTIVE LONGWAVE TROUGH FROM THE MID MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES. THE SHORTWAVE THAT PRODUCED ISOLATED STRONG STORMS
ACROSS THE FAR EASTERN COUNTIES SATURDAY WAS MOVING SOUTHWEST
TOWARD THE UPPER TEXAS COAST.

ONE MORE VERY HOT DAY TODAY WITH HIGHS 100-105 DEGREES ACROSS MUCH
OF NORTH TEXAS. CHECK OF RECORDS AT BOTH WACO AND DFW INDICATE
RECORD WILL REMAIN INTACT. CURRENT RECORDS ARE 106 AT WACO AND 109
AT DFW. THE HEAT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM THIS
EVENING. HOWEVER...SOME CHANGES ARE IN STORE FOR THE AREA. A
SHORTWAVE DISTURBANCE ASSOCIATED WITH WEAKENING CONVECTION OVER
SOUTHWEST KANSAS WILL DROP SOUTH ACROSS OKLAHOMA THIS AFTERNOON.
IN ADDITION...OUTFLOW FROM THE DYING KANSAS COMPLEX WILL HELP
SPEED UP THE SOUTHWARD PUSH OF THE COLD FRONT THROUGH OKLAHOMA AND
TOWARD THE RED RIVER VALLEY LATE THIS AFTERNOON AND INTO THIS
EVENING. THE HRRR IS THE FASTEST WITH THE FRONT/OUTFLOW PER
LATEST INDICATIONS... WITH THE NAM NEXT IN LINE AND THE GFS AND
TECH WRF MODELS SLIGHTLY SLOWER. SINCE THIS BOUNDARY IS MESOSCALE
DRIVEN...WILL LEAN MORE TOWARD A FASTER SOLUTION OF THE HRRR/NAM.

SPEED DISCREPANCIES ASIDE...THE FRONT WILL BE ENTERING THE RED
RIVER VALLEY RIGHT AT PEAK HEATING. ISOLATED THUNDERSTORMS WILL
BE POSSIBLE ACROSS THE NORTHERN TIER COUNTIES JUST BEFORE 00Z
LABOR DAY...THEN MORE SCATTERED ACROSS THE NORTHERN COUNTIES IN
THE VICINITY OF THE FRONT IN THE EVENING HOURS. THE 750-500MB RH
INCREASES WITH STEEP LOW LEVEL LAPSE RATES IN THE LOWER LEVELS.
MID LEVEL INSTABILITY IS NOT EXPECTED TO BE EXTREME DUE TO THE
INFLUENCE OF THE EASTERN PERIPHERY OF THE UPPER HIGH. PWAT VALUES
WILL BE NEAR 2 STANDARD DEVIATIONS FOR THIS TIME OF YEAR.
LOCALIZED MICROBURSTS WITH HEAVY DOWNPOURS WILL BE LIKELY WITH
STRONGER ACTIVITY THROUGH NIGHTFALL WITH A WEAKENING TREND AFTER
DARK DUE TO THE LOSS OF DAYTIME HEATING. WE HAVE INTRODUCED A
SLIGHT CHANCE ACROSS THE NORTHERN COUNTIES FOR LATE AFTERNOON AS
THE FRONT ARRIVES INTO THE RED RIVER VALLEY. WITH LIFT FROM THE
SHORTWAVE AND THE FRONT ENTERING AREAS NORTH OF I-20...WE HAVE
RAISED POPS NORTH OF I-20 THIS EVENING WHILE GENERALLY MAINTAINING
BEST CHANCES ACROSS THE WESTERN COUNTIES OVERNIGHT AS A STORM
CLUSTER SHIFTS SOUTH THROUGH A HIGHER INSTABILITY AXIS.

THE WEAK COLD FRONT SHOULD SHIFT SOUTH OF I-20 BY TUESDAY MORNING
WITH INFLUENCE OF STORM-DRIVEN COLD POOL INDICATED BY THE MODELS.
THIS IS WHERE CONFIDENCE WANES WITH UNCERTAINTY ON SUCH MESOSCALE
DRIVEN FEATURES AND WHERE THEY END UP. FOR NOW HAVE MAINTAIN LOW
CONVECTIVE CHANCES FROM THE PREVIOUS FORECAST CONTINGENT ON THE
SOUTH-SOUTHWEST PROGRESSION OF THE SHORTWAVE TOWARD THE HILL
COUNTRY. A COUPLE OF MODELS INDICATE ANOTHER SUBTLE SHORTWAVE
ROTATING AROUND THE UPPER HIGH AND ACROSS CENTRAL AND SOUTHEAST
TEXAS LATER ON TUESDAY. HAVE INTRODUCED LOW POPS ACROSS THE
CENTRAL TEXAS COUNTIES TO ACCOUNT FOR THIS FEATURE. FOR THE LATTER
HALF OF NEXT WEEK...THE UPPER HIGH LOOKS TO EXPAND EAST ACROSS THE
SOUTHERN PLAINS ONCE AGAIN AND WILL KEEP BETTER FORCING OFF TO
SOUTHEAST. BY NEXT WEEKEND... THERE ARE SIGNS OF THE UPPER HIGH
POSSIBLY RETROGRADING WEST AGAIN WITH A WEAK PIECE OF ENERGY
DROPPING SOUTHWEST ACROSS THE SABINE RIVER VALLEY. THIS COULD LEAD
TO LOW RAIN CHANCES ACROSS THE EASTERN HALF OF NORTH TEXAS ONCE
AGAIN BUT WILL LEAVE THE FORECAST DRY WITH LACK OF CONFIDENCE ON
WHERE THIS FEATURE TRACKS.

05/



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 103  79  98  77  98 /  10  30  20  20  10
WACO, TX             102  77 100  75  98 /  10  20  20  20  20
PARIS, TX            101  74  96  71  96 /  10  30  20  10  10
DENTON, TX           103  77  97  72  97 /  10  40  20  10  10
MCKINNEY, TX         102  76  97  73  98 /  10  30  20  10  10
DALLAS, TX           104  80  98  78  99 /  10  30  20  20  10
TERRELL, TX          102  78  98  75  98 /  10  30  20  20  10
CORSICANA, TX        101  77 100  75  98 /  10  20  20  20  10
TEMPLE, TX           100  74  98  74  97 /  10  10  20  20  20
MINERAL WELLS, TX    103  74  95  73  96 /  10  40  30  20  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR TXZ103-104-118-119.


&&

$$







AREA FORECAST DISCUSSION...UPDATED

NWS FORT WORTH TX

 616 AM CDT SUN SEP 1 2013

.AVIATION...
CONCERNS...ISOLATED TO SCATTERED CONVECTION TONIGHT.

FOR THIS FORECAST CYCLE...HAVE DECIDED TO KEEP ALL TAFS VFR.
HOWEVER...A CONVECTIVE OUTFLOW BOUNDARY...CURRENTLY MOVING THROUGH
CENTRAL OKLAHOMA...IS A CONCERN FOR THE METROPLEX TERMINALS AS IT IS
EXPECTED TO MOVE SOUTH OF THE RED RIVER LATER THIS AFTERNOON. THIS
BOUNDARY SHOULD BE ABLE TO FIRE ISOLATED TO WIDELY SCATTERED
CONVECTION BETWEEN THE RED RIVER AND I-20 MID-LATE AFTERNOON AND
OVERNIGHT PER LAST SEVERAL HI- RES RUNS AS WELL AS THE GFS AND NAM
SERIES. ERGO...HAVE DECIDED TO ADD A PROB30 0205/0209 FOR THIS
POTENTIAL. ALSO...A WIND SHIFT IS INDICATED FOR THE KDFW EXTENDED
FORECAST AFTER 02/15Z. 75

&&


.PREV DISCUSSION... /ISSUED 319 AM CDT SUN SEP 1 2013/
NORTH TEXAS WILL BE UNDERNEATH NORTH-NORTHWEST FLOW THE NEXT FEW
DAYS...AS THE UPPER HIGH WILL BE ANCHORED TO THE WEST WITH AN
ACTIVE LONGWAVE TROUGH FROM THE MID MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES. THE SHORTWAVE THAT PRODUCED ISOLATED STRONG STORMS
ACROSS THE FAR EASTERN COUNTIES SATURDAY WAS MOVING SOUTHWEST
TOWARD THE UPPER TEXAS COAST.

ONE MORE VERY HOT DAY TODAY WITH HIGHS 100-105 DEGREES ACROSS MUCH
OF NORTH TEXAS. CHECK OF RECORDS AT BOTH WACO AND DFW INDICATE
RECORD WILL REMAIN INTACT. CURRENT RECORDS ARE 106 AT WACO AND 109
AT DFW. THE HEAT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM THIS
EVENING. HOWEVER...SOME CHANGES ARE IN STORE FOR THE AREA. A
SHORTWAVE DISTURBANCE ASSOCIATED WITH WEAKENING CONVECTION OVER
SOUTHWEST KANSAS WILL DROP SOUTH ACROSS OKLAHOMA THIS AFTERNOON.
IN ADDITION...OUTFLOW FROM THE DYING KANSAS COMPLEX WILL HELP
SPEED UP THE SOUTHWARD PUSH OF THE COLD FRONT THROUGH OKLAHOMA AND
TOWARD THE RED RIVER VALLEY LATE THIS AFTERNOON AND INTO THIS
EVENING. THE HRRR IS THE FASTEST WITH THE FRONT/OUTFLOW PER
LATEST INDICATIONS... WITH THE NAM NEXT IN LINE AND THE GFS AND
TECH WRF MODELS SLIGHTLY SLOWER. SINCE THIS BOUNDARY IS MESOSCALE
DRIVEN...WILL LEAN MORE TOWARD A FASTER SOLUTION OF THE HRRR/NAM.

SPEED DISCREPANCIES ASIDE...THE FRONT WILL BE ENTERING THE RED
RIVER VALLEY RIGHT AT PEAK HEATING. ISOLATED THUNDERSTORMS WILL
BE POSSIBLE ACROSS THE NORTHERN TIER COUNTIES JUST BEFORE 00Z
LABOR DAY...THEN MORE SCATTERED ACROSS THE NORTHERN COUNTIES IN
THE VICINITY OF THE FRONT IN THE EVENING HOURS. THE 750-500MB RH
INCREASES WITH STEEP LOW LEVEL LAPSE RATES IN THE LOWER LEVELS.
MID LEVEL INSTABILITY IS NOT EXPECTED TO BE EXTREME DUE TO THE
INFLUENCE OF THE EASTERN PERIPHERY OF THE UPPER HIGH. PWAT VALUES
WILL BE NEAR 2 STANDARD DEVIATIONS FOR THIS TIME OF YEAR.
LOCALIZED MICROBURSTS WITH HEAVY DOWNPOURS WILL BE LIKELY WITH
STRONGER ACTIVITY THROUGH NIGHTFALL WITH A WEAKENING TREND AFTER
DARK DUE TO THE LOSS OF DAYTIME HEATING. WE HAVE INTRODUCED A
SLIGHT CHANCE ACROSS THE NORTHERN COUNTIES FOR LATE AFTERNOON AS
THE FRONT ARRIVES INTO THE RED RIVER VALLEY. WITH LIFT FROM THE
SHORTWAVE AND THE FRONT ENTERING AREAS NORTH OF I-20...WE HAVE
RAISED POPS NORTH OF I-20 THIS EVENING WHILE GENERALLY MAINTAINING
BEST CHANCES ACROSS THE WESTERN COUNTIES OVERNIGHT AS A STORM
CLUSTER SHIFTS SOUTH THROUGH A HIGHER INSTABILITY AXIS.

THE WEAK COLD FRONT SHOULD SHIFT SOUTH OF I-20 BY TUESDAY MORNING
WITH INFLUENCE OF STORM-DRIVEN COLD POOL INDICATED BY THE MODELS.
THIS IS WHERE CONFIDENCE WANES WITH UNCERTAINTY ON SUCH MESOSCALE
DRIVEN FEATURES AND WHERE THEY END UP. FOR NOW HAVE MAINTAIN LOW
CONVECTIVE CHANCES FROM THE PREVIOUS FORECAST CONTINGENT ON THE
SOUTH-SOUTHWEST PROGRESSION OF THE SHORTWAVE TOWARD THE HILL
COUNTRY. A COUPLE OF MODELS INDICATE ANOTHER SUBTLE SHORTWAVE
ROTATING AROUND THE UPPER HIGH AND ACROSS CENTRAL AND SOUTHEAST
TEXAS LATER ON TUESDAY. HAVE INTRODUCED LOW POPS ACROSS THE
CENTRAL TEXAS COUNTIES TO ACCOUNT FOR THIS FEATURE. FOR THE LATTER
HALF OF NEXT WEEK...THE UPPER HIGH LOOKS TO EXPAND EAST ACROSS THE
SOUTHERN PLAINS ONCE AGAIN AND WILL KEEP BETTER FORCING OFF TO
SOUTHEAST. BY NEXT WEEKEND... THERE ARE SIGNS OF THE UPPER HIGH
POSSIBLY RETROGRADING WEST AGAIN WITH A WEAK PIECE OF ENERGY
DROPPING SOUTHWEST ACROSS THE SABINE RIVER VALLEY. THIS COULD LEAD
TO LOW RAIN CHANCES ACROSS THE EASTERN HALF OF NORTH TEXAS ONCE
AGAIN BUT WILL LEAVE THE FORECAST DRY WITH LACK OF CONFIDENCE ON
WHERE THIS FEATURE TRACKS.

05/

&&



.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102  79  98  77  98 /  10  40  20  20  10
WACO, TX             101  77 100  75  98 /   5  20  20  20  20
PARIS, TX            101  74  96  71  96 /  20  30  20  10  10
DENTON, TX           103  77  97  72  97 /  20  40  20  10  10
MCKINNEY, TX         102  76  97  73  98 /  20  40  20  10  10
DALLAS, TX           103  80  98  78  99 /  10  40  20  20  10
TERRELL, TX          102  78  98  75  98 /  10  30  20  20  10
CORSICANA, TX        101  77 100  75  98 /  10  20  20  20  10
TEMPLE, TX            99  74  98  74  97 /   5  10  20  20  20
MINERAL WELLS, TX    102  74  95  73  96 /  10  40  30  20  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR TXZ103-104-118-119.


&&

$$

75/






AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 319 AM CDT SUN SEP 1 2013

.DISCUSSION...
NORTH TEXAS WILL BE UNDERNEATH NORTH-NORTHWEST FLOW THE NEXT FEW
DAYS...AS THE UPPER HIGH WILL BE ANCHORED TO THE WEST WITH AN
ACTIVE LONGWAVE TROUGH FROM THE MID MISSISSIPPI VALLEY TO THE MID
ATLANTIC STATES. THE SHORTWAVE THAT PRODUCED ISOLATED STRONG STORMS
ACROSS THE FAR EASTERN COUNTIES SATURDAY WAS MOVING SOUTHWEST
TOWARD THE UPPER TEXAS COAST.

ONE MORE VERY HOT DAY TODAY WITH HIGHS 100-105 DEGREES ACROSS MUCH
OF NORTH TEXAS. CHECK OF RECORDS AT BOTH WACO AND DFW INDICATE
RECORD WILL REMAIN INTACT. CURRENT RECORDS ARE 106 AT WACO AND 109
AT DFW. THE HEAT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM THIS
EVENING. HOWEVER...SOME CHANGES ARE IN STORE FOR THE AREA. A
SHORTWAVE DISTURBANCE ASSOCIATED WITH WEAKENING CONVECTION OVER
SOUTHWEST KANSAS WILL DROP SOUTH ACROSS OKLAHOMA THIS AFTERNOON.
IN ADDITION...OUTFLOW FROM THE DYING KANSAS COMPLEX WILL HELP
SPEED UP THE SOUTHWARD PUSH OF THE COLD FRONT THROUGH OKLAHOMA AND
TOWARD THE RED RIVER VALLEY LATE THIS AFTERNOON AND INTO THIS
EVENING. THE HRRR IS THE FASTEST WITH THE FRONT/OUTFLOW PER
LATEST INDICATIONS... WITH THE NAM NEXT IN LINE AND THE GFS AND
TECH WRF MODELS SLIGHTLY SLOWER. SINCE THIS BOUNDARY IS MESOSCALE
DRIVEN...WILL LEAN MORE TOWARD A FASTER SOLUTION OF THE HRRR/NAM.

SPEED DISCREPANCIES ASIDE...THE FRONT WILL BE ENTERING THE RED
RIVER VALLEY RIGHT AT PEAK HEATING. ISOLATED THUNDERSTORMS WILL
BE POSSIBLE ACROSS THE NORTHERN TIER COUNTIES JUST BEFORE 00Z
LABOR DAY...THEN MORE SCATTERED ACROSS THE NORTHERN COUNTIES IN
THE VICINITY OF THE FRONT IN THE EVENING HOURS. THE 750-500MB RH
INCREASES WITH STEEP LOW LEVEL LAPSE RATES IN THE LOWER LEVELS.
MID LEVEL INSTABILITY IS NOT EXPECTED TO BE EXTREME DUE TO THE
INFLUENCE OF THE EASTERN PERIPHERY OF THE UPPER HIGH. PWAT VALUES
WILL BE NEAR 2 STANDARD DEVIATIONS FOR THIS TIME OF YEAR.
LOCALIZED MICROBURSTS WITH HEAVY DOWNPOURS WILL BE LIKELY WITH
STRONGER ACTIVITY THROUGH NIGHTFALL WITH A WEAKENING TREND AFTER
DARK DUE TO THE LOSS OF DAYTIME HEATING. WE HAVE INTRODUCED A
SLIGHT CHANCE ACROSS THE NORTHERN COUNTIES FOR LATE AFTERNOON AS
THE FRONT ARRIVES INTO THE RED RIVER VALLEY. WITH LIFT FROM THE
SHORTWAVE AND THE FRONT ENTERING AREAS NORTH OF I-20...WE HAVE
RAISED POPS NORTH OF I-20 THIS EVENING WHILE GENERALLY MAINTAINING
BEST CHANCES ACROSS THE WESTERN COUNTIES OVERNIGHT AS A STORM
CLUSTER SHIFTS SOUTH THROUGH A HIGHER INSTABILITY AXIS.

THE WEAK COLD FRONT SHOULD SHIFT SOUTH OF I-20 BY TUESDAY MORNING
WITH INFLUENCE OF STORM-DRIVEN COLD POOL INDICATED BY THE MODELS.
THIS IS WHERE CONFIDENCE WANES WITH UNCERTAINTY ON SUCH MESOSCALE
DRIVEN FEATURES AND WHERE THEY END UP. FOR NOW HAVE MAINTAIN LOW
CONVECTIVE CHANCES FROM THE PREVIOUS FORECAST CONTINGENT ON THE
SOUTH-SOUTHWEST PROGRESSION OF THE SHORTWAVE TOWARD THE HILL
COUNTRY. A COUPLE OF MODELS INDICATE ANOTHER SUBTLE SHORTWAVE
ROTATING AROUND THE UPPER HIGH AND ACROSS CENTRAL AND SOUTHEAST
TEXAS LATER ON TUESDAY. HAVE INTRODUCED LOW POPS ACROSS THE
CENTRAL TEXAS COUNTIES TO ACCOUNT FOR THIS FEATURE. FOR THE LATTER
HALF OF NEXT WEEK...THE UPPER HIGH LOOKS TO EXPAND EAST ACROSS THE
SOUTHERN PLAINS ONCE AGAIN AND WILL KEEP BETTER FORCING OFF TO
SOUTHEAST. BY NEXT WEEKEND... THERE ARE SIGNS OF THE UPPER HIGH
POSSIBLY RETROGRADING WEST AGAIN WITH A WEAK PIECE OF ENERGY
DROPPING SOUTHWEST ACROSS THE SABINE RIVER VALLEY. THIS COULD LEAD
TO LOW RAIN CHANCES ACROSS THE EASTERN HALF OF NORTH TEXAS ONCE
AGAIN BUT WILL LEAVE THE FORECAST DRY WITH LACK OF CONFIDENCE ON
WHERE THIS FEATURE TRACKS.

05/

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102  79  98  77  98 /  10  40  20  20  10
WACO, TX             101  77 100  75  98 /   5  20  20  20  20
PARIS, TX            101  74  96  71  96 /  20  30  20  10  10
DENTON, TX           103  77  97  72  97 /  20  40  20  10  10
MCKINNEY, TX         102  76  97  73  98 /  20  40  20  10  10
DALLAS, TX           103  80  98  78  99 /  10  40  20  20  10
TERRELL, TX          102  78  98  75  98 /  10  30  20  20  10
CORSICANA, TX        101  77 100  75  98 /  10  20  20  20  10
TEMPLE, TX            99  74  98  74  97 /   5  10  20  20  20
MINERAL WELLS, TX    102  74  95  73  96 /  10  40  30  20  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR TXZ103-104-118-119.


&&

$$

05/








AREA FORECAST DISCUSSION

NWS LUBBOCK TX

 1146 PM CDT SAT AUG 31 2013

.AVIATION...
IN THE SHORT TERM A CLUSTER OF THUNDERSTORMS OVER SOUTHWEST KANSAS
IS SHOWING SOME TENDENCY TO DRIFT TO THE SOUTH-SOUTHEAST AND MAY
YET END UP IN THE SOUTHEAST PANHANDLE LATER TONIGHT NOT FAR FROM
KCDS. MOST SOLUTIONS DIMINISH THIS ACTIVITY BEFORE REACHING KCDS
WHILE THE LATEST HRRR DOES BRING LIGHTER SHOWERS TO THE AREA AFTER
14Z. WE REMAIN UNCONVINCED SO WILL RETAIN THE MID LEVEL CLOUD
INCREASE AT KCDS AFTER 14Z. OTHERWISE...ARRIVAL OF THE COLD FRONT
BY LATE SUNDAY EVENING OR POSSIBLY DELAYED UNTIL EARLY MONDAY
MORNING SHOULD OFFER AT LEAST SOME OPPORTUNITY FOR THUNDER AT BOTH
KLBB AND KCDS. LATEST SOLUTIONS ARE NOT TERRIBLY EAGER TO MOVE
ACTIVITY IN BEFORE 06Z HOWEVER. WE WILL FOLLOW THIS LACKADAISICAL
APPROACH AND AVOID ADDING IMPLICIT THUNDER TO THE END OF THE 06Z
TAFS JUST YET. RMCQUEEN

&&

.PREV DISCUSSION... /ISSUED 617 PM CDT SAT AUG 31 2013/

AVIATION...
QUIET VFR CONDITIONS IN STORE THIS EVENING AND OVERNIGHT ALTHOUGH
DEVELOPING ISOLATED THUNDERSTORMS OVER THE OKLAHOMA PANHANDLE WILL
HAVE A TENDENCY TO DRIFT SOUTHEAST THROUGH THE EASTERN TEXAS
PANHANDLE OVERNIGHT. ALL SOLUTIONS END ACTIVITY BEFORE REACHING
CHILDRESS...ALTHOUGH A MID LEVEL CLOUD LAYER SEEMS LIKELY TO
SURVIVE INTO KCDS EARLY SUNDAY ALONG WITH PERHAPS A SHIFT TO MORE
VARIABLE SURFACE WINDS. WILL TRY TO ADDRESS THIS WITH MORE
CONFIDENCE FOR THE 06Z TAF. OTHERWISE FOCUS WILL BE TOWARDS
INCREASING THUNDER CHANCES FOR BOTH TAF SITES JUST BEYOND THE END
OF THIS TAF PERIOD WITH APPROACHING WEAK COLD FRONT. RMCQUEEN

PREV DISCUSSION... /ISSUED 245 PM CDT SAT AUG 31 2013/

SHORT TERM...
THE PERSISTENT UPPER RIDGE CENTERED OVER NEW MEXICO WAS PROVIDING
ANOTHER HOT DAY FOR THE SOUTH PLAINS REGION. 19Z TEMPERATURES WERE
RUNNING 1-3 DEGREES ABOVE YESTERDAY AT THIS TIME...VARYING FROM THE
MID-90S ON THE CAPROCK TO AT OR JUST ABOVE 100 ACROSS THE FAR
EASTERN ZONES. THE HIGH SO FAR AT KLBB HAS REACHED 97 DEGREES AND
WILL TOP OUT VERY CLOSE TO THE RECORD OF 100 DEGREES...SET BACK IN
1930. THE STRONG HEATING AND RESULTANT DEEP MIXING WAS NOW
SUPPORTING A FEW HIGH-BASED CUMULUS...THOUGH LIMITED
MOISTURE/INSTABILITY AND WARM MID-LEVELS SHOULD KEEP THESE CLOUDS
LIMITED IN VERTICAL EXTENT. INSTEAD...THE CLOSEST CONVECTION WAS
FIRING ACROSS THE HIGHER TERRAIN OF NEW MEXICO AND COLORADO...WITH
ADDITIONAL DEVELOPMENT POSSIBLE INTO THE NORTHERN TEXAS PANHANDLE
THROUGH WESTERN KANSAS. WEAK STEERING FLOW WILL DIRECT THIS ACTIVITY
SLOWLY SOUTHEASTWARD AND THERE IS AN OUTSIDE CHANCE DECAYING
CONVECTION COULD AFFECT THE NORTHEAST ZONES LATE TONIGHT/EARLY
SUNDAY...THOUGH THE MORE LIKELY OUTCOME IS AN INCREASE IN MID/HIGH
CLOUDINESS.

THE WESTERN RIDGE WILL AMPLIFY OVER THE ROCKIES THROUGH SUNDAY IN
ADVANCE OF AN UPPER LOW OFF THE WEST COAST WHILE A POTENT SHORTWAVE
TROUGH TRANSLATES ACROSS THE UPPER MIDWEST AND INTO THE GREAT LAKES.
THIS MODEST PATTERN ADJUSTMENT WILL ALLOW HEIGHTS TO DECREASE
SLIGHTLY LOCALLY WHILE ALSO CAUSING THE MONSOONAL MOISTURE PLUME TO
BEND SOUTHWARD AND OVER THE AREA LATER IN THE DAY. IN ADDITION...THE
PASSING NORTHERN WAVE WILL PROPEL A COLD FRONT SOUTHWARD THROUGH THE
PLAINS...WITH THE LATEST INDICATIONS THAT THE FRONT WILL BE NEAR OR
INTO OUR NORTHERN ZONES BY LATE SUNDAY AFTERNOON. THE COMBINATION OF
THE FRONT...IMPROVED MID-LEVEL MOISTURE AND PERHAPS WEAK UPPER
SUPPORT WITHIN THE MOISTURE PLUME WILL RESULTING IN INCREASING
SHOWER/STORM CHANCES SUNDAY AFTERNOON INTO SUNDAY NIGHT. BEFORE
00Z...EXPECT THE BEST CHANCE OF CONVECTION TO FAVOR THE NORTHERN
HALF OF THE CWA WHERE SLIGHT CHANCE POPS WERE MAINTAINED. RELATIVELY
HOT AND DRY LOW LEVELS WITH AN INVERTED-V PROFILE COUPLED WITH MOIST
MID/UPPER LEVELS COULD SUPPORT A FEW STRONG WIND GUSTS WITH ANY MORE
INTENSE RAIN CORES. ALSO THE BETTER MOISTURE ALOFT AND RESULTING
INCREASING PWATS /FROM 1 TO 1.5 INCHES/ COUPLED WITH RELATIVELY SLOW
STEERING FLOW COULD SUPPORT DECENT RAINFALL IN A FEW SPOTS...THOUGH
COVERAGE OF CONVECTION MAY BE FAIRLY LIMITED. OTHERWISE...WE WILL
SEE ANOTHER MILD NIGHT TONIGHT...SIMILAR TO THIS MORNING. IT WILL
BE HOT AGAIN SUNDAY BUT INCREASED CLOUD COVER AND LOWERING
THICKNESSES AND HEIGHTS SHOULD KNOCK TEMPERATURES DOWN A TOUCH FROM
TODAY FOR MOST SPOTS.

LONG TERM...
COLD FRONT TO SAG SWD THROUGH THE FCST AREA SUNDAY EXPECTED TO
CONTINUE TO FOCUS THUNDER DEVELOPMENT MAINLY ACROSS THE NRN ZONES
THROUGH THE EVENING. FOCUS LIKELY TO SHIFT SLIGHTLY TO THE ROLLING
PLAINS OVERNIGHT AS UPPER SUPPORT ROTATING AROUND THE SRN ROCKIES
RIDGE STAYS JUST TO THE EAST OF THE FCST AREA. PRE-06Z POPS LOOK
GOOD AS THEY ARE BUT WILL ADJUST 06Z-12Z POPS WITH 30S EAST AND
20S ELSEWHERE.

STILL APPEARS TO BE SOME POTENTIAL FOR SHOWERS AND THUNDER MONDAY
AFTN POSSIBLY LINGERING INTO THE EVENING IN UPSLOPE FLOW REGIME TO
THE NORTH OF THE FRONT WHICH BY THAT TIME LIKELY TO BE DRAPED
ACROSS THE PERMIAN BASIN. THIS SHOULD FOCUS POPS TOWARD THE SWRN
THIRD OF THE FCST AREA...ALTHOUGH CONFIDENCE NOT QUITE HIGH ENOUGH
TO BUMP INTO CHANCE CATEGORY.

REMAINDER OF THE PERIOD LOOKS TO BE DRY WITH TEMPS AT OR JUST
ABOVE SEASONAL NORMS. STILL SOME MODEL DIFFERENCES ON HOW THE
RIDGE OVER THE SRN ROCKIES EXPANDS WITH RECENT TRENDS SUGGEST
EXPANSION MORE NWD RATHER THAN EWD ONTO THE PLAINS. LAST SEVERAL
ITERATIONS OF MEDIUM-RANGE MOS GUIDANCE KEEPS KLBB HIGHS IN A
RANGE FROM 89-92 DEGREES. CURRENT FCST FOR MID TO LATE WEEK IN
GREAT SHAPE WITH FEW CHANGES TO BE MADE.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        64  93  63  87  63 /  10  20  30  20  20
TULIA         67  93  65  87  64 /   0  20  30  20  20
PLAINVIEW     66  94  65  87  64 /   0  20  30  20  20
LEVELLAND     64  97  66  88  66 /   0  10  20  20  20
LUBBOCK       71  97  68  89  66 /   0  10  20  20  20
DENVER CITY   63  95  66  87  64 /   0  10  20  20  20
BROWNFIELD    65  98  68  89  66 /   0  10  20  20  20
CHILDRESS     70  99  69  92  67 /  10  20  30  20  10
SPUR          71 101  70  89  68 /   0  10  20  20  20
ASPERMONT     73 101  71  91  70 /   0  10  20  20  20

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

99/99/05






AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 359 PM EDT SUN SEP 1 2013

.SYNOPSIS...
UPPER AIR DISTURBANCES WILL MOVE EAST ACROSS THE AREA THIS EVENING
AND AGAIN MONDAY WITH A COLD FRONT MOVING THROUGH BY TUESDAY.
THIS FRONT WILL BRING A DRIER AIRMASS TO THE REGION THROUGH THE
END OF NEXT WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 250 PM EDT SUNDAY...

BANDS OF SHRA/TSRA CONTINUE TO SPREAD EAST ACROSS THE REGION
LATE THIS AFTERNOON AHEAD OF A WEAK VORT LOBE THAT LOOKS TO SWING
ACROSS THE MOUNTAINS BY THIS EVENING BEFORE EXITING TO THE EAST
OVERNIGHT. BEST INSTABILITY REMAINS ALONG/EAST OF THE BLUE RIDGE
WHERE SUPPORTED BY HIGHER LOW LEVEL THETA-E AND WEAK CONVERGENCE.
LATEST HRRR AND SIMILAR NAM SOLUTIONS EVENTUALLY PUSH BEST
COVERAGE OF STORMS INTO THE NE CWA BY THIS EVENING FOLLOWED BY
DECENT DRYING BEHIND THE WAVE OVERNIGHT. HOWEVER WITH POTENTIAL
FOR SEVERAL BANDS OF SHRA INTO THE EVENING WILL HAVE THE HIGHER
LIKELY POPS BLUE RIDGE WEST EARLY WITH MAINLY HIGH CHANCES TO THE
EAST. CUT PRECIP BACK OVERNIGHT AS THE AREA SLIPS IN BETWEEN
IMPULSES WITH ONLY ISOLATED COVERAGE LIKELY AT THIS POINT. HOWEVER
SHOULD BE PLENTY OF FOG AROUND AS CLOUDS CLEAR SOME LATER ON AND
TEMPS FALL BACK INTO THE 60S MOST SPOTS.

5H TROF WILL SLOWLY SAG INTO THE AREA ON MONDAY WITH THE
ASSOCIATED SURFACE COLD FRONT STILL WEST OF THE MOUNTAINS
THROUGH LATE IN THE DAY. THIS COMBO WITH MORE WESTERLY FLOW TO
INIT SHOULD LIMIT SHRA EARLY ON FOLLOWED BY INCREASING AFTERNOON
COVERAGE FAR WEST...AND ALONG THE BLUE RIDGE AS THE LOW LEVEL FLOW
SLOWLY BACKS. MODELS GIVEN MORE INSOLATION AND LESS EARLY
SHRA...NOW SHOWING MORE INSTABILITY ALTHOUGH WIND FIELDS ALOFT
LOOK RATHER WEAK. THUS HAVE CUT BACK ON POPS DURING THE MORNING TO
LOW CHANCE OR SLIGHTS...WITH A GRADUAL INCREASE TO LIKELYS OVER
THE FAR WEST LATER IN THE AFTERNOON. MAY SEE THE PIEDMONT ACTUALLY
GO DRY FOR THE MOST PART UNTIL LATE BUT LEFT CHANCE COVERAGE THERE
FOR NOW GIVEN HEATING. WILL BE A HOT LABOR DAY WITH 85H TEMPS NEAR
+20C WHICH SHOULD ALLOW MOST OUTSIDE THE HIGHER RIDGES TO TOP 80
WITH PERHAPS LOW 90S EAST PENDING EARLY CLOUDS AND LATER TSRA.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 330 PM EDT SUNDAY...

COLD FRONT MOVES THROUGH MONDAY NIGHT BUT WITH A FEW DISTURBANCES
BEHIND IT AND REMAINING MOISTURE...STILL A GOOD CHANCE OF SHOWERS
FOR THE FIRST HALF OF THE NIGHT...ESPECIALLY IN THE WEST.
IMPRESSIVE PUNCH OF DRIER AIR ARRIVES ON DOWNSLOPING WINDS AS
SKIES BEGIN TO CLEAR INTO TUESDAY MORNING. ALTHOUGH THERE IS SOME
POSITIVE ENERGY IN THE SOUNDING TUESDAY AFTERNOON...APPEARS TO BE
JUST TOO MUCH DRY AIR ABOVE H85 TO GET ANY STORMS GOING. MOISTURE
HANGS A BIT CLOSER TO THE FRONT ACROSS THE SOUTHSIDE SO LEFT SOME
POPS THERE. FOR SOME REASON...THE NAM SOUNDINGS ARE FAR TOO
AGGRESSIVE WITH CAPE ON TUESDAY...MOST LIKELY BECAUSE DEWPOINTS
FROM THE NAM AND THE MET MOS ARE 6-8F WARMER THAN THE
GFS/MAV/ECMWF. WITH LOW TO MID 50S DEWPOINTS ARRIVING LATE
TUESDAY...SOME OF THE COLDEST SPOTS OF SE WEST VA AND EXTREME SW
VA MAY TOUCH THE UPPER 40S TUESDAY NIGHT. AT THIS POINT...COOL
AND DRY HIGH PRESSURE WILL RULE THE REST OF THE SHORT TERM WITH
ONLY PASSING HIGH CLOUDS. WEDNESDAY NIGHT HAS THE POTENTIAL TO BE
JUST AS CHILLY AS TUESDAY NIGHT...ALTHOUGH MORE HIGH CLOUDS MAY
KEEP TEMPS UP A TAD. FOR HIGH TEMPS WEDNESDAY...THE ONLY PLACE 80S
WILL BE FOUND WILL BE THE LOWEST ELEVATIONS.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 330 PM EDT SUNDAY...

THE DRY PATTERN CONTINUES AS TEMPS SLOWLY WARM...ALTHOUGH NOT AS
FAST AS WHAT THE OPERATIONAL GFS HAS. H85 TEMPS FROM THAT MODEL
ARE SEVERAL DEGREES WARMER THAN THE ECMWF. AGREE WITH THE SLOWER
WARMUP BUT NOT AS COOL AS THE ECMWF MOS. NONETHELESS...BOTH
MODELS ARE MOSTLY DRY...UNTIL AN EASTERN TROUGH ONCE AGAIN
DEEPENS. SUBTLE INDICATIONS IN THE MASS FIELDS FROM THE ECMWF THAT
A BACKDOOR FRONT MAY CROSS SATURDAY OR SUNDAY. WITH THAT
SAID...THERE STILL REALLY ISN`T MUCH QPF TO BE FOUND ON EITHER
MODEL THROUGH DAY 7.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AS OF 100 PM EDT SUNDAY...

BAND OF SHRA/TSRA HEADING ACROSS THE WEST WILL CONTINUE TO PUSH
EAST AND LIKELY STRENGTHEN UPON NEARING THE BLUE RIDGE IN THE NEXT
HOUR OR TWO. THUS ADDING MORE PREVAILING LOWERING OF CIGS/VSBYS
TO MVFR FROM KROA WEST THROUGH MID AFTERNOON ALTHOUGH EXPECTING
HEAVIER COVERAGE TO PASS JUST SOUTH OF THESE TAF SITES. ALSO GIVEN
INCREASING INSTABILITY ACROSS THE EAST WILL GO AHEAD AND INCLUDE A
VCTS MENTION ACROSS THE EASTERN SITES AFTER 3 OR 4 PM. THIS COULD
BRIEFLY DROP THESE LOCATIONS INTO IFR PENDING IF THEY SEE A
HEAVIER SHRA/TSRA. THINK COVERAGE WILL BECOME MORE SCATTERED OVER
THE WEST ONCE THE CURRENT BATCH OF SHRA/TSRA MOVES THROUGH BUT
LIKELY NOT UNTIL LATE THIS AFTERNOON AT THIS POINT.

WEAKENING IN THE CONVECTION THIS EVENING WITH FOG AGAIN FORMING
OVERNIGHT AT MOST SITES...WITH FOG BECOMING DENSE AT
KLWB/KBCB...AND MAYBE KLYH IF SHOWERS OCCUR NEARBY.

TRUE FRONT EXPECTED TO NOT MOVE INTO AND THRU THE CWA UNTIL
TUESDAY MORNING...SO MONDAY WILL BE ANOTHER DAY OF SCATTERED
CONVECTION WITH THE LAST IN THE UPPER LEVEL SHORTWAVES MOVING
ACROSS INTERACTING WITH HUMID SFC CONDITIONS AND LOW LVL
CONVERGENCE. HOWEVER SINCE MOST WIDESPREAD COVERAGE NOT EXPECTED
UNTIL NEAR OR AFTER THE END OF THE VALID TAF PERIOD WONT INCLUDE
ANY SHRA/TSRA MENTION AFTER FOG/STRATUS FADES. ANTICIPATE MORE
FOG TUESDAY MORNING WITH DRIER AIR NOSING IN DURING THE DAY
TUESDAY. MOSTLY VFR EXPECTED THROUGH LATE WEEK OUTSIDE OF ANY
OVERNIGHT FOG.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...JH/RCS/WP
NEAR TERM...JH
SHORT TERM...KM
LONG TERM...KM
AVIATION...DS/JH/RCS/WP




AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 327 PM EDT SUN SEP 1 2013

.SYNOPSIS...
UPPER AIR DISTURBANCES WILL MOVE EAST ACROSS THE AREA THIS EVENING
AND AGAIN MONDAY WITH A COLD FRONT MOVING THROUGH BY TUESDAY.
THIS FRONT WILL BRING A DRIER AIRMASS TO THE REGION FOR THE MIDDLE
OF THE WEEK.
&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 250 PM EDT SUNDAY...

BANDS OF SHRA/TSRA CONTINUE TO SPREAD EAST ACROSS THE REGION
LATE THIS AFTERNOON AHEAD OF A WEAK VORT LOBE THAT LOOKS TO SWING
ACROSS THE MOUNTAINS BY THIS EVENING BEFORE EXITING TO THE EAST
OVERNIGHT. BEST INSTABILITY REMAINS ALONG/EAST OF THE BLUE RIDGE
WHERE SUPPORTED BY HIGHER LOW LEVEL THETA-E AND WEAK CONVERGENCE.
LATEST HRRR AND SIMILAR NAM SOLUTIONS EVENTUALLY PUSH BEST
COVERAGE OF STORMS INTO THE NE CWA BY THIS EVENING FOLLOWED BY
DECENT DRYING BEHIND THE WAVE OVERNIGHT. HOWEVER WITH POTENTIAL
FOR SEVERAL BANDS OF SHRA INTO THE EVENING WILL HAVE THE HIGHER
LIKELY POPS BLUE RIDGE WEST EARLY WITH MAINLY HIGH CHANCES TO THE
EAST. CUT PRECIP BACK OVERNIGHT AS THE AREA SLIPS IN BETWEEN
IMPULSES WITH ONLY ISOLATED COVERAGE LIKELY AT THIS POINT. HOWEVER
SHOULD BE PLENTY OF FOG AROUND AS CLOUDS CLEAR SOME LATER ON AND
TEMPS FALL BACK INTO THE 60S MOST SPOTS.

5H TROF WILL SLOWLY SAG INTO THE AREA ON MONDAY WITH THE
ASSOCIATED SURFACE COLD FRONT STILL WEST OF THE MOUNTAINS
THROUGH LATE IN THE DAY. THIS COMBO WITH MORE WESTERLY FLOW TO
INIT SHOULD LIMIT SHRA EARLY ON FOLLOWED BY INCREASING AFTERNOON
COVERAGE FAR WEST...AND ALONG THE BLUE RIDGE AS THE LOW LEVEL FLOW
SLOWLY BACKS. MODELS GIVEN MORE INSOLATION AND LESS EARLY
SHRA...NOW SHOWING MORE INSTABILITY ALTHOUGH WIND FIELDS ALOFT
LOOK RATHER WEAK. THUS HAVE CUT BACK ON POPS DURING THE MORNING TO
LOW CHANCE OR SLIGHTS...WITH A GRADUAL INCREASE TO LIKELYS OVER
THE FAR WEST LATER IN THE AFTERNOON. MAY SEE THE PIEDMONT ACTUALLY
GO DRY FOR THE MOST PART UNTIL LATE BUT LEFT CHANCE COVERAGE THERE
FOR NOW GIVEN HEATING. WILL BE A HOT LABOR DAY WITH 85H TEMPS NEAR
+20C WHICH SHOULD ALLOW MOST OUTSIDE THE HIGHER RIDGES TO TOP 80
WITH PERHAPS LOW 90S EAST PENDING EARLY CLOUDS AND LATER TSRA.
&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SATURDAY...

MODELS ARE IN DECENT AGREEMENT THAT AN ASSOCIATED COLD FRONT WILL
ENTER OUR SOUTHEAST WEST VIRGINIA COUNTIES TUESDAY MORNING...AND
CONTINUE SOUTHEAST...EXITING OUR AREA DURING THE AFTERNOON. THE
TRULY DRIER AIR IN THE LOW LEVELS WILL LAG A FEW HOURS BEHIND THE
FRONT...SO EXPECT WE WILL STILL SEE A COUPLE SHOWERS AND
THUNDERSTORMS SOUTH OF INTERSTATE 81 THROUGH SUNSET...AT WHICH
POINT INSTABILITY WILL DISAPPEAR.

CANADIAN HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BRINGING WITH IT A HINT OF AUTUMN AS
TEMPERATURES FOR MID WEEK ARE EXPECTED TO BE SLIGHTLY BELOW NORMAL
FOR EARLY SEPTEMBER.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 400 PM EDT SATURDAY...

A STRONG RIDGE CONTINUES IN THE WEST...WHILE AMPLIFYING TROUGH
ANTICIPATED IN THE EAST. HIGH PRESSURE WILL CONTROL OUR WEATHER
PATTERN FOR THURSDAY...RESULTING IN DRY CONDITIONS WITH MOSTLY
CLEAR SKIES...OUTSIDE OF EARLY MORNING FOG. ANOTHER COLD FRONT
WILL DROP SOUTHEAST ACROSS THE REGION FRIDAY WITH SOME MOISTURE
AND INSTABILITY...KEPT THE MENTION OF ISOLATED TO SCATTERED
SHOWERS WITH FRONTAL BOUNDARY. ISOLATED AFTERNOON CONVECTION IS
POSSIBLE SATURDAY AFTERNOON WITH BEST CHANCES ACROSS THE HIGHER
TERRAIN. TEMPERATURES INITIALLY START BELOW NORMAL THEN SLOWLY
MODERATE INTO THE WEEKEND.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
AS OF 100 PM EDT SUNDAY...

BAND OF SHRA/TSRA HEADING ACROSS THE WEST WILL CONTINUE TO PUSH
EAST AND LIKELY STRENGTHEN UPON NEARING THE BLUE RIDGE IN THE NEXT
HOUR OR TWO. THUS ADDING MORE PREVAILING LOWERING OF CIGS/VSBYS
TO MVFR FROM KROA WEST THROUGH MID AFTERNOON ALTHOUGH EXPECTING
HEAVIER COVERAGE TO PASS JUST SOUTH OF THESE TAF SITES. ALSO GIVEN
INCREASING INSTABILITY ACROSS THE EAST WILL GO AHEAD AND INCLUDE A
VCTS MENTION ACROSS THE EASTERN SITES AFTER 3 OR 4 PM. THIS COULD
BRIEFLY DROP THESE LOCATIONS INTO IFR PENDING IF THEY SEE A
HEAVIER SHRA/TSRA. THINK COVERAGE WILL BECOME MORE SCATTERED OVER
THE WEST ONCE THE CURRENT BATCH OF SHRA/TSRA MOVES THROUGH BUT
LIKELY NOT UNTIL LATE THIS AFTERNOON AT THIS POINT.

WEAKENING IN THE CONVECTION THIS EVENING WITH FOG AGAIN FORMING
OVERNIGHT AT MOST SITES...WITH FOG BECOMING DENSE AT
KLWB/KBCB...AND MAYBE KLYH IF SHOWERS OCCUR NEARBY.

TRUE FRONT EXPECTED TO NOT MOVE INTO AND THRU THE CWA UNTIL
TUESDAY MORNING...SO MONDAY WILL BE ANOTHER DAY OF SCATTERED
CONVECTION WITH THE LAST IN THE UPPER LEVEL SHORTWAVES MOVING
ACROSS INTERACTING WITH HUMID SFC CONDITIONS AND LOW LVL
CONVERGENCE. HOWEVER SINCE MOST WIDESPREAD COVERAGE NOT EXPECTED
UNTIL NEAR OR AFTER THE END OF THE VALID TAF PERIOD WONT INCLUDE
ANY SHRA/TSRA MENTION AFTER FOG/STRATUS FADES. ANTICIPATE MORE
FOG TUESDAY MORNING WITH DRIER AIR NOSING IN DURING THE DAY
TUESDAY. MOSTLY VFR EXPECTED THROUGH LATE WEEK OUTSIDE OF ANY
OVERNIGHT FOG.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...JH/RCS/WP
NEAR TERM...JH
SHORT TERM...NF
LONG TERM...KK
AVIATION...DS/JH/RCS/WP




AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 112 PM EDT SUN SEP 1 2013

.SYNOPSIS...
UPPER AIR DISTURBANCES WILL MOVE EAST ACROSS THE AREA THROUGH
MONDAY WITH A COLD FRONT MOVING THROUGH BY TUESDAY. THIS FRONT
WILL BRING A DRIER AIRMASS TO THE REGION FOR THE MIDDLE OF NEXT
WEEK.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT SUNDAY...

BAND OF SHRA/TSRA APPROACHING FROM THE SW WILL BE PUSHING NE INTO
THE FAR WESTERN AREAS AROUND 11 AM...AND THEN LIKELY AID NEW
DEVELOPMENT FARTHER EAST AS INSTABILITY INCREASES PER EARLY
HEATING. EARLY ARRIVAL OF CONVECTION MAY TEND TO LIMIT THE WESTERN
SEVERE THREAT TO SOME DEGREE ESPCLY GIVEN WEAKER WINDS ALOFT OFF
MORNING RAOBS AND DEEP MOISTURE TO 6H. HOWEVER LATEST SHORT RANGE
GUIDANCE REMAINS VARIED ON LATER TRENDS WITH SOME TAKING BETTER
LIFT TO THE SW OF THE AREA WITH THE OLD OUTFLOW UNFOLDING INTO THE
TN VALLEY...WHILE THE HRRR BRINGS A SWATH OF SHRA/TSRA EAST ALONG
THE RESIDUAL VORT AXIS. THIS LOOKS BEST IN LINE WITH THE CURRENT
SCENARIO ESPCLY GIVEN DECENT INSTABILITY OFF MODIFIED RAOBS WEST
AND BETTER HEATING EAST WHERE INITIAL LIFT MAY GET WEAKENED SOME
VIA DOWNSLOPE. THUS HAVE UPPED POPS TO LIKELYS A BIT SOONER FAR
WEST AND EXTENDED EAST TO THE BLUE RIDGE FOR NOW. LEFT CHANCE POPS
IN THE EAST FOR LATER DEVELOPMENT ALTHOUGH MAY NEED TO RAISE LATER
PENDING TRENDS. KEPT HIGHS A LITTLE COOLER...75-80 OVER THE SW
GIVEN EARLIER ARRIVAL OF SHRA...WITH THE EAST PUSHING 90 UNDER
WEAK WESTERLY FLOW AND 85H TEMPS OF +18C.

PREVIOUS VALID DISCUSSION...

HAVE ADJUSTED POPS DOWNWARD EARLY THEN BLEND INTO THE HIGHER POPS
BY MIDDAY OVER THE WEST. THINK ANY OUTFLOW AND HIGHER THETA-E
ACROSS THE MTNS WILL BE ENOUGH TO GET SHRA/TSRA GOING BEFORE NOON
ACROSS SE WV/FAR SW VA. THE 06Z NAM/00Z ECMWF CONTINUE TO
ADVERTISE MORE ORGANZIED CONVECTION MOVING FROM NRN KY INTO ERN
WV/SHENANDOAH VALLEY OF VA THIS AFTERNOON WITH 6Z GFS SINGLING OUT
THE MOUNTAINS OF NC/FAR SW VA. OVERALL KEPT THE LIKELY POPS OVER
THE WEST BY EARLY AFTERNOON TAPERING TO SCATTERED EAST OF THE BLUE
RIDGE. ANY FOG EARLY WILL BURN OFF BY 10 AM.

PREVIOUS DISCUSSION AT 330 AM...

EARLY THIS MORNING...SEEING SOME DENSE FOG ACROSS THE AREA
RESULTING FROM LACK OF LOWER OR MID CLOUDS AND WET GROUND FROM
SATURDAYS RAINS. WILL MAINTAIN SPECIAL WX STATEMENTS FOR
THIS...GIVEN THAT WILL SEE UPSTREAM CLOUDINESS ARRIVING THAT MAY
CAUSE VSBYS TO FLUCTUATE ENOUGH TO KEEP THE COVERAGE OF DENSE FOG
TO A LOCALIZED/PATCHY STATE.

HAVE STAYED CLOSER TO THE 00Z GFS SOLUTION THIS PERIOD AS IT WAS
HANDLING THE UPPER SHORTWAVE ACROSS OHIO AND STORMS OVER KY THIS
MORNING BETTER THAN THE OTHER MODELS. THE LOCAL WRF/HRRR NOT ALL
THAT BAD EITHER BUT APPEAR TO BE OVERDOING PRECIP IN THE EAST AS
RADAR IS CLEAR.

SO FOR TODAY...STILL LOOKS LIKELY THAT SHOWERS AND STORMS WILL
IMPACT THE MOUNTAINS BY MIDDAY...THEN SHIFT ENE ACROSS THE REST OF
THE AREA THRU THE AFTERNOON. THE FLOW WILL BE SW TO WEST WHICH MAY
LIMIT COVERAGE AS WE HEAD DOWNSTREAM OF THE BLUE RIDGE SO LEFT POPS
IN THE FOOTHILLS PIEDMONT AREAS TO 30/4O WHILE GOING LIKELY OR HIGH
CHANCE WEST. PWATS REMAINING HIGH WILL FAVOR HEAVY RAINERS AS STORM
MOTION WILL BE IN THE 10-20 MPH RANGE. SEVERE THREAT WILL BE
ISOLATED TO WIND DAMAGE FROM OUTFLOW/DOWNBURSTS. WILL CONTINUE TO
MENTION THE RAIN/SVR THREAT IN THE HWO.

AS THE WAVE PASSES THIS EVENING...THE CENTRAL/ERN CWA SHOULD SEE
DRYING TREND. NEXT UPSTREAM WAVE WILL BE WEAKENING AS IT MOVES FROM
KY INTO WV OVERNIGHT...BUT ENOUGH THETA-E/HIGH MOISTURE AHEAD OF THE
FRONT TO KEEP HIGHER POPS ACROSS THE SE WV/FAR SW VA AFTER MIDNIGHT
BUT ONLY ABOUT 30/40 POPS.

WITH MAINLY A MIX OF CLOUDS/SUN TODAY WILL STILL SEE WARM TEMPS IN
THE MAV/MET BLEND RANGE FROM UPPER 70S/LOWER 80S MOUNTAINS...TO NEAR
90 PIEDMONT.

TONIGHT...MUGGY CONDITIONS REMAIN WITH TEMPS FALLING INTO THE 60S.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SATURDAY...

LOOKING AHEAD TO MONDAY...THE APPALACHIAN CHAIN WILL BE SITUATED AT
THE BASE OF A BROAD UPPER LEVEL TROUGH EXTENDING SOUTHWARD FROM THE
GREAT LAKES...RESULTING IN WESTERLY WINDFLOW ACROSS OUR AREA. ASIDE
FROM A FEW SHOWERS SPILLING OVER OUR FAR WESTERN RIDGELINES...THIS
WEST WIND WILL KEEP A LID ON CONVECTION DURING THE MORNING AND MUCH
OF THE AFTERNOON...BEFORE AN UPPER LEVEL DISTURBANCE APPROACHES
DURING THE EVENING. CLOUD COVER WILL BE SCATTERED EAST OF THE BLUE
RIDGE...MAINLY CONFINED TO MID AND HIGH CLOUDS...AND BELIEVE THE
COMBINATION OF THE DOWNSLOPE WIND AND FILTERED SUNSHINE REACHING THE
SURFACE WILL BE SUFFICIENT TO ALLOW TEMPERATURES TO REACH INTO THE
LOWER 90S IN A FEW AREA OF THE PIEDMONTS.

AS MENTIONED...AN UPPER LEVEL DISTURBANCE IS EXPECTED TO MOVE IN
FROM THE WEST DURING THE EVENING...INCREASING THE COVERAGE OF
SHOWERS AND THUNDERSTORMS ACROSS OUR AREA. INSTABILITY ASSOCIATED
WITH THE DISTURBANCE WILL BE SUFFICIENT TO ALLOW A FEW THUNDERSTORMS
TO BECOME SEVERE...AND EXPECT THE BIGGER THREAT TO COME IN THE FORM
OF DAMAGING WINDS. ATMOSPHERIC MOISTURE WILL REMAIN ABUNDANT...AND
EXPECT WE WILL ALSO SEE A FEW STORMS PRODUCE HEAVY RAIN...AND
POSSIBLY LOCALIZED FLASH FLOODING. THUNDERSTORM ACTIVITY WILL
DECREASE LATE MONDAY NIGHT/EARLY TUESDAY AS THIS DISTURBANCE
MOVES EAST.

MODELS ARE IN DECENT AGREEMENT THAT AN ASSOCIATED COLD FRONT WILL
ENTER OUR SOUTHEAST WEST VIRGINIA COUNTIES TUESDAY MORNING...AND
CONTINUE SOUTHEAST...EXITING OUR AREA DURING THE AFTERNOON. THE TRULY
DRIER AIR IN THE LOW LEVELS WILL LAG A FEW HOURS BEHIND THE
FRONT...SO EXPECT WE WILL STILL SEE A COUPLE SHOWERS AND
THUNDERSTORMS SOUTH OF INTERSTATE 81 THROUGH SUNSET...AT WHICH POINT
INSTABILITY WILL DISAPPEAR.

CANADIAN HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BRINGING WITH IT A HINT OF AUTUMN AS
TEMPERATURES FOR MID WEEK ARE EXPECTED TO BE SLIGHTLY BELOW NORMAL
FOR EARLY SEPTEMBER.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 400 PM EDT SATURDAY...

A STRONG RIDGE CONTINUES IN THE WEST...WHILE AMPLIFYING TROUGH
ANTICIPATED IN THE EAST. HIGH PRESSURE WILL CONTROL OUR WEATHER
PATTERN FOR THURSDAY...RESULTING IN DRY CONDITIONS WITH MOSTLY
CLEAR SKIES...OUTSIDE OF EARLY MORNING FOG. ANOTHER COLD FRONT
WILL DROP SOUTHEAST ACROSS THE REGION FRIDAY WITH SOME MOISTURE
AND INSTABILITY...KEPT THE MENTION OF ISOLATED TO SCATTERED
SHOWERS WITH FRONTAL BOUNDARY. ISOLATED AFTERNOON CONVECTION IS
POSSIBLE SATURDAY AFTERNOON WITH BEST CHANCES ACROSS THE HIGHER
TERRAIN. TEMPERATURES INITIALLY START BELOW NORMAL THEN SLOWLY
MODERATE INTO THE WEEKEND.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
AS OF 100 PM EDT SUNDAY...

BAND OF SHRA/TSRA HEADING ACROSS THE WEST WILL CONTINUE TO PUSH
EAST AND LIKELY STRENGTHEN UPON NEARING THE BLUE RIDGE IN THE NEXT
HOUR OR TWO. THUS ADDING MORE PREVAILING LOWERING OF CIGS/VSBYS
TO MVFR FROM KROA WEST THROUGH MID AFTERNOON ALTHOUGH EXPECTING
HEAVIER COVERAGE TO PASS JUST SOUTH OF THESE TAF SITES. ALSO GIVEN
INCREASING INSTABILITY ACROSS THE EAST WILL GO AHEAD AND INCLUDE A
VCTS MENTION ACROSS THE EASTERN SITES AFTER 3 OR 4 PM. THIS COULD
BRIEFLY DROP THESE LOCATIONS INTO IFR PENDING IF THEY SEE A
HEAVIER SHRA/TSRA. THINK COVERAGE WILL BECOME MORE SCATTERED OVER
THE WEST ONCE THE CURRENT BATCH OF SHRA/TSRA MOVES THROUGH BUT
LIKELY NOT UNTIL LATE THIS AFTERNOON AT THIS POINT.

WEAKENING IN THE CONVECTION THIS EVENING WITH FOG AGAIN FORMING
OVERNIGHT AT MOST SITES...WITH FOG BECOMING DENSE AT
KLWB/KBCB...AND MAYBE KLYH IF SHOWERS OCCUR NEARBY.

TRUE FRONT EXPECTED TO NOT MOVE INTO AND THRU THE CWA UNTIL
TUESDAY MORNING...SO MONDAY WILL BE ANOTHER DAY OF SCATTERED
CONVECTION WITH THE LAST IN THE UPPER LEVEL SHORTWAVES MOVING
ACROSS INTERACTING WITH HUMID SFC CONDITIONS AND LOW LVL
CONVERGENCE. HOWEVER SINCE MOST WIDESPREAD COVERAGE NOT EXPECTED
UNTIL NEAR OR AFTER THE END OF THE VALID TAF PERIOD WONT INCLUDE
ANY SHRA/TSRA MENTION AFTER FOG/STRATUS FADES. ANTICIPATE MORE
FOG TUESDAY MORNING WITH DRIER AIR NOSING IN DURING THE DAY
TUESDAY. MOSTLY VFR EXPECTED THROUGH LATE WEEK OUTSIDE OF ANY
OVERNIGHT FOG.
&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...RCS/WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KK
AVIATION...DS/JH/RCS/WP




AREA FORECAST DISCUSSION

NWS BLACKSBURG VA

 1004 AM EDT SUN SEP 1 2013

.SYNOPSIS...
UPPER AIR DISTURBANCES WILL MOVE EAST ACROSS THE AREA THROUGH
MONDAY WITH A COLD FRONT MOVING THROUGH BY TUESDAY. THIS FRONT
WILL BRING A DRIER AIRMASS TO THE REGION FOR THE MIDDLE OF NEXT
WEEK.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT SUNDAY...

BAND OF SHRA/TSRA APPROACHING FROM THE SW WILL BE PUSHING NE INTO
THE FAR WESTERN AREAS AROUND 11 AM...AND THEN LIKELY AID NEW
DEVELOPMENT FARTHER EAST AS INSTABILITY INCREASES PER EARLY
HEATING. EARLY ARRIVAL OF CONVECTION MAY TEND TO LIMIT THE WESTERN
SEVERE THREAT TO SOME DEGREE ESPCLY GIVEN WEAKER WINDS ALOFT OFF
MORNING RAOBS AND DEEP MOISTURE TO 6H. HOWEVER LATEST SHORT RANGE
GUIDANCE REMAINS VARIED ON LATER TRENDS WITH SOME TAKING BETTER
LIFT TO THE SW OF THE AREA WITH THE OLD OUTFLOW UNFOLDING INTO THE
TN VALLEY...WHILE THE HRRR BRINGS A SWATH OF SHRA/TSRA EAST ALONG
THE RESIDUAL VORT AXIS. THIS LOOKS BEST IN LINE WITH THE CURRENT
SCENARIO ESPCLY GIVEN DECENT INSTABILITY OFF MODIFIED RAOBS WEST
AND BETTER HEATING EAST WHERE INITIAL LIFT MAY GET WEAKENED SOME
VIA DOWNSLOPE. THUS HAVE UPPED POPS TO LIKELYS A BIT SOONER FAR
WEST AND EXTENDED EAST TO THE BLUE RIDGE FOR NOW. LEFT CHANCE POPS
IN THE EAST FOR LATER DEVELOPMENT ALTHOUGH MAY NEED TO RAISE LATER
PENDING TRENDS. KEPT HIGHS A LITTLE COOLER...75-80 OVER THE SW
GIVEN EARLIER ARRIVAL OF SHRA...WITH THE EAST PUSHING 90 UNDER
WEAK WESTERLY FLOW AND 85H TEMPS OF +18C.

PREVIOUS VALID DISCUSSION...

HAVE ADJUSTED POPS DOWNWARD EARLY THEN BLEND INTO THE HIGHER POPS
BY MIDDAY OVER THE WEST. THINK ANY OUTFLOW AND HIGHER THETA-E
ACROSS THE MTNS WILL BE ENOUGH TO GET SHRA/TSRA GOING BEFORE NOON
ACROSS SE WV/FAR SW VA. THE 06Z NAM/00Z ECMWF CONTINUE TO
ADVERTISE MORE ORGANZIED CONVECTION MOVING FROM NRN KY INTO ERN
WV/SHENANDOAH VALLEY OF VA THIS AFTERNOON WITH 6Z GFS SINGLING OUT
THE MOUNTAINS OF NC/FAR SW VA. OVERALL KEPT THE LIKELY POPS OVER
THE WEST BY EARLY AFTERNOON TAPERING TO SCATTERED EAST OF THE BLUE
RIDGE. ANY FOG EARLY WILL BURN OFF BY 10 AM.

PREVIOUS DISCUSSION AT 330 AM...

EARLY THIS MORNING...SEEING SOME DENSE FOG ACROSS THE AREA
RESULTING FROM LACK OF LOWER OR MID CLOUDS AND WET GROUND FROM
SATURDAYS RAINS. WILL MAINTAIN SPECIAL WX STATEMENTS FOR
THIS...GIVEN THAT WILL SEE UPSTREAM CLOUDINESS ARRIVING THAT MAY
CAUSE VSBYS TO FLUCTUATE ENOUGH TO KEEP THE COVERAGE OF DENSE FOG
TO A LOCALIZED/PATCHY STATE.

HAVE STAYED CLOSER TO THE 00Z GFS SOLUTION THIS PERIOD AS IT WAS
HANDLING THE UPPER SHORTWAVE ACROSS OHIO AND STORMS OVER KY THIS
MORNING BETTER THAN THE OTHER MODELS. THE LOCAL WRF/HRRR NOT ALL
THAT BAD EITHER BUT APPEAR TO BE OVERDOING PRECIP IN THE EAST AS
RADAR IS CLEAR.

SO FOR TODAY...STILL LOOKS LIKELY THAT SHOWERS AND STORMS WILL
IMPACT THE MOUNTAINS BY MIDDAY...THEN SHIFT ENE ACROSS THE REST OF
THE AREA THRU THE AFTERNOON. THE FLOW WILL BE SW TO WEST WHICH MAY
LIMIT COVERAGE AS WE HEAD DOWNSTREAM OF THE BLUE RIDGE SO LEFT POPS
IN THE FOOTHILLS PIEDMONT AREAS TO 30/4O WHILE GOING LIKELY OR HIGH
CHANCE WEST. PWATS REMAINING HIGH WILL FAVOR HEAVY RAINERS AS STORM
MOTION WILL BE IN THE 10-20 MPH RANGE. SEVERE THREAT WILL BE
ISOLATED TO WIND DAMAGE FROM OUTFLOW/DOWNBURSTS. WILL CONTINUE TO
MENTION THE RAIN/SVR THREAT IN THE HWO.

AS THE WAVE PASSES THIS EVENING...THE CENTRAL/ERN CWA SHOULD SEE
DRYING TREND. NEXT UPSTREAM WAVE WILL BE WEAKENING AS IT MOVES FROM
KY INTO WV OVERNIGHT...BUT ENOUGH THETA-E/HIGH MOISTURE AHEAD OF THE
FRONT TO KEEP HIGHER POPS ACROSS THE SE WV/FAR SW VA AFTER MIDNIGHT
BUT ONLY ABOUT 30/40 POPS.

WITH MAINLY A MIX OF CLOUDS/SUN TODAY WILL STILL SEE WARM TEMPS IN
THE MAV/MET BLEND RANGE FROM UPPER 70S/LOWER 80S MOUNTAINS...TO NEAR
90 PIEDMONT.

TONIGHT...MUGGY CONDITIONS REMAIN WITH TEMPS FALLING INTO THE 60S.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AS OF 400 AM EDT SATURDAY...

LOOKING AHEAD TO MONDAY...THE APPALACHIAN CHAIN WILL BE SITUATED AT
THE BASE OF A BROAD UPPER LEVEL TROUGH EXTENDING SOUTHWARD FROM THE
GREAT LAKES...RESULTING IN WESTERLY WINDFLOW ACROSS OUR AREA. ASIDE
FROM A FEW SHOWERS SPILLING OVER OUR FAR WESTERN RIDGELINES...THIS
WEST WIND WILL KEEP A LID ON CONVECTION DURING THE MORNING AND MUCH
OF THE AFTERNOON...BEFORE AN UPPER LEVEL DISTURBANCE APPROACHES
DURING THE EVENING. CLOUD COVER WILL BE SCATTERED EAST OF THE BLUE
RIDGE...MAINLY CONFINED TO MID AND HIGH CLOUDS...AND BELIEVE THE
COMBINATION OF THE DOWNSLOPE WIND AND FILTERED SUNSHINE REACHING THE
SURFACE WILL BE SUFFICIENT TO ALLOW TEMPERATURES TO REACH INTO THE
LOWER 90S IN A FEW AREA OF THE PIEDMONTS.

AS MENTIONED...AN UPPER LEVEL DISTURBANCE IS EXPECTED TO MOVE IN
FROM THE WEST DURING THE EVENING...INCREASING THE COVERAGE OF
SHOWERS AND THUNDERSTORMS ACROSS OUR AREA. INSTABILITY ASSOCIATED
WITH THE DISTURBANCE WILL BE SUFFICIENT TO ALLOW A FEW THUNDERSTORMS
TO BECOME SEVERE...AND EXPECT THE BIGGER THREAT TO COME IN THE FORM
OF DAMAGING WINDS. ATMOSPHERIC MOISTURE WILL REMAIN ABUNDANT...AND
EXPECT WE WILL ALSO SEE A FEW STORMS PRODUCE HEAVY RAIN...AND
POSSIBLY LOCALIZED FLASH FLOODING. THUNDERSTORM ACTIVITY WILL
DECREASE LATE MONDAY NIGHT/EARLY TUESDAY AS THIS DISTURBANCE
MOVES EAST.

MODELS ARE IN DECENT AGREEMENT THAT AN ASSOCIATED COLD FRONT WILL
ENTER OUR SOUTHEAST WEST VIRGINIA COUNTIES TUESDAY MORNING...AND
CONTINUE SOUTHEAST...EXITING OUR AREA DURING THE AFTERNOON. THE TRULY
DRIER AIR IN THE LOW LEVELS WILL LAG A FEW HOURS BEHIND THE
FRONT...SO EXPECT WE WILL STILL SEE A COUPLE SHOWERS AND
THUNDERSTORMS SOUTH OF INTERSTATE 81 THROUGH SUNSET...AT WHICH POINT
INSTABILITY WILL DISAPPEAR.

CANADIAN HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BRINGING WITH IT A HINT OF AUTUMN AS
TEMPERATURES FOR MID WEEK ARE EXPECTED TO BE SLIGHTLY BELOW NORMAL
FOR EARLY SEPTEMBER.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 400 PM EDT SATURDAY...

A STRONG RIDGE CONTINUES IN THE WEST...WHILE AMPLIFYING TROUGH
ANTICIPATED IN THE EAST. HIGH PRESSURE WILL CONTROL OUR WEATHER
PATTERN FOR THURSDAY...RESULTING IN DRY CONDITIONS WITH MOSTLY
CLEAR SKIES...OUTSIDE OF EARLY MORNING FOG. ANOTHER COLD FRONT
WILL DROP SOUTHEAST ACROSS THE REGION FRIDAY WITH SOME MOISTURE
AND INSTABILITY...KEPT THE MENTION OF ISOLATED TO SCATTERED
SHOWERS WITH FRONTAL BOUNDARY. ISOLATED AFTERNOON CONVECTION IS
POSSIBLE SATURDAY AFTERNOON WITH BEST CHANCES ACROSS THE HIGHER
TERRAIN. TEMPERATURES INITIALLY START BELOW NORMAL THEN SLOWLY
MODERATE INTO THE WEEKEND.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
AS OF 735 AM EDT SUNDAY...

LIFR/VLIFR AT LWB/BCB/LYH AND DAN AT 12Z WILL LIFT TO VFR BY 15Z.

WILL SEE SHOWERS/TSRA ARRIVING IN THE BLF/LWB CORRIDOR AROUND
MIDDAY THEN NEXT AT BCB AND ROA BY 19Z. KEPT VCTS AT THESE SITES
BUT NO MENTION OF IT AT DAN/LYH. ANTICIPATING AT LEAST SOME TIME
THIS AFTERNOON THAT THE TAF SITES FROM ROA/BCB TO LWB/BLF WILL SEE
A STORM IMPACT THE TERMINAL BUT NOT ENOUGH CONFIDENCE YET TO PIN
DOWN THE TIMING. OVERALL VFR EXPECTED TODAY WHILE STORMS COULD
DROP HEAVY RAIN/GUSTY WINDS SENDING VSBYS/CIGS TO UNDER VFR.

WEAKENING IN THE CONVECTION THIS EVENING WITH FOG AGAIN FORMING
OVERNIGHT AT MOST SITES...WITH FOG BECOMING DENSE AT LWB/BCB...AND
MAYBE LYH IF IT RAINS NEARBY.

TRUE FRONT EXPECTED TO NOT MOVE INTO AND THRU THE CWA UNTIL
TUESDAY MORNING...SO MONDAY WILL BE ANOTHER DAY OF SCATTERED
CONVECTION WITH THE LAST IN THE UPPER LEVEL SHORTWAVES MOVING
ACROSS INTERACTING WITH HUMID SFC CONDITIONS AND LOW LVL
CONVERGENCE. ANTICIPATE MORE FOG TUESDAY MORNING WITH DRIER AIR
NOSING IN DURING THE DAY TUESDAY. MOSTLY VFR WX EXPECTED THROUGH
LATE WEEK OUTSIDE OF ANY OVERNIGHT FOG.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

$$
SYNOPSIS...RCS/WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KK
AVIATION...DS/RCS/WP




AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 612 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 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 612 PM CDT MON SEP 2 2013

THE PERSISTENT BAND OF CLOUDS IS FINALLY DISSIPATING/MOVING SOUTH
OF THE AREA AND BOTH TAF SITES SHOULD HAVE SCATTERED OUT OR BE
CLEAR BY 00Z. HIGH PRESSURE WILL THEN BE OVERHEAD FOR TONIGHT AND
MOVE SLOWLY OFF TO THE EAST FOR TUESDAY. VFR CONDITIONS EXPECTED
THROUGH THE PERIOD FOR KRST. CONDITIONS APPEAR TO BE FAVORABLE FOR
A VALLEY FOG EVENT WITH IFR CONDITIONS LATE TONIGHT AT KLSE. WITH
THE HIGH OVERHEAD...LIGHT WINDS WILL BE IN PLACE THROUGH AT LEAST
5 THOUSAND FEET AND GOOD RADIATIONAL COOLING WILL OCCUR WITH THE
CLEAR SKIES. THE 02.18Z NAM SHOWS SATURATION OCCURRING AT THE
SURFACE STARTING ALREADY AT 06Z AND REMAINING THROUGH ABOUT 14Z.
HOWEVER...THE 02.21Z RAP DOES NOT SHOW SATURATION OCCURRING AND
MAINTAINS A 1 TO 2C TEMP/DEW POINT SPREAD THROUGH THE NIGHT AND
WONDERING IF THIS IS REFLECTION OF THE RECENT STRETCH OF DRY
WEATHER AND DRY SOIL CONDITIONS. THIS IS NOT ENOUGH TO GO AWAY
FROM A VALLEY FOG EVENT OCCURRING BUT RAISES ENOUGH DOUBT THAT
CANNOT CONSIDER THIS A SLAM DUNK EVENT.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04







AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

 1132 AM CDT SUN SEP 1 2013

.AVIATION/18Z TAFS/...LINGERING IFR/MVFR STRATUS FIELD ACROSS SC
WI WITH COLD FRONT APPROACHING FROM SW WI. EXPECTING SCT TSRA
DEVELOPMENT. HRRR HAS A PRETTY GOOD HANDLE ON TRENDS...SHOWING
WINDOW FOR STORMS 18-00Z...NW-SE ACROSS THE CWA. LOW SVR THREAT
PER SWODY1...BUT ISOLD STG/SVR PLAUSIBLE. COLD ADVECTION KICKS IN
TONIGHT WITH LOW LEVEL THERMAL TROUGH ACROSS WI ON MONDAY. EXPECT
DECENT AMOUNT OF STRATOCU IN THIS REGIME. 850 TEMPS 8-10C.

PC

&&

.PREV DISCUSSION... /ISSUED 330 AM CDT SUN SEP 1 2013/

TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM

WEBCAMS AND SURFACE OBS SHOWING EXPANDING AREAS OF DENSE FOG OVER
SOUTHEAST CWA LAST SEVERAL HOURS.  ALSO SEVERAL COUNTY SHERIFFS
REPORTING AREAS OF DENSE FOG CENTERED ON WASHINGTON AND WAUKESHA
COUNTIES.  UPSTREAM MID-HIGH CLOUDS FROM MN CONVECTION CONTINUING TO
THIN SO THINKING AREAS OF DENSE FOG WILL PERSIST THROUGH 13Z OR SO
IN THE EASTERN CWA.  HENCE POSTED DENSE FOG ADVY FOR NOW.  HELD OFF
ON INCLUDING AREAS FURTHER WEST DUE TO MORE CLOUDS AND SOME INCREASE
IN BOUNDARY LAYER MIXING.

STRONG FORCING ASSOCIATED WITH VIGOROUS SHORT WAVE OVER NE MN/WRN LK
SUPERIOR WILL REMAIN MOSTLY NORTH OF CWA TODAY...HOWEVER WEAKER LIFT
ASSOCIATED WITH LOBE OF DIFFERENTIAL VORTICITY WILL PASS THROUGH
DURING THE DAY. AXIS OF Q-VECTOR CONVERGENCE DOES COINCIDE WITH LOW
LEVEL MOISTURE FLUX CONVERGENCE PASSING THRU WESTERN CWA THIS
MORNING...AND LATE MORNING AND EARLY AFTN IN THE EAST.  WITH LOW
LEVEL FRONTOGENETICAL FORCING SPLITTING TO THE NORTH AND SOUTH AS
FRONT PASSES THRU SRN WI...WL CONTINUE WITH HIGH CHANCE POPS TODAY.

BULK SHEAR INCREASES TO AROUND 30 KNOTS WITH CAPES AROUND 2000 J.
CAN NOT RULE OUT MULTI-CELLS WITH A FEW SUPERCELLS VICINITY OF
FRONT...ESPECIALLY IN THE SOUTHEAST CWA THIS AFTN.  EXPC ANY
CONVECTION TO END BY EARLY EVENING EXCEPT A FEW STRAGGLERS MAY HANG
ON IN THE FAR EAST.  OTHER DRIER AND LESS HUMID CONDITIONS WILL
SETTLE IN TONIGHT.  MAY BE SOME LOW CLOUDS ACCOMPANYING COLD AIR
ADVECTION OVERNIGHT.

LABOR DAY AND TUESDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH

HIGH PRESSURE WILL BUILD INTO THE AREA ON LABOR DAY. THE MAIN
ISSUE AT THIS POINT IS FIGURING OUT HOW MUCH SKY COVER THERE WILL
BE. MODELS DO TRY AND HOLD ONTO SOME LOW LEVEL MOISTURE THROUGH
MUCH OF THE DAY...WITH SOUNDINGS SUGGESTING AT LEAST SCATTERED TO
MAYBE EVEN BROKEN CLOUDS INTO THE AFTERNOON. MOISTURE IS PRETTY
THIN THOUGH...SO MAY NOT TAKE MUCH TO SCATTER OUT THE CLOUDS AS
THE HIGH MOVES IN. BUMPED SKY COVER UP A BIT FROM MOSTLY CLEAR
SKIES. OTHERWISE...STILL LOOKS LIKE A PRETTY PLEASANT DAY WITH
TEMPS A FEW DEGREES BELOW NORMAL.

THE HIGH WILL BE ABOUT RIGHT OVERHEAD BY TUESDAY MORNING...SO KEPT
PATCHY TO AREAS OF FOG IN THE FORECAST FOR LATE MONDAY NIGHT AND
EARLY TUESDAY MORNING. SHOULD THEN SEE MOSTLY SUNNY SKIES THROUGH
THE DAY TUESDAY UNDER THE HIGH...WITH TEMPS RECOVERING BACK TO
AROUND NORMAL FOR EARLY SEPTEMBER.

WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE...MEDIUM TO HIGH

HIGH PRESSURE WILL PERSIST THOUGH THURSDAY...WITH MOSTLY CLEAR TO
PARTLY CLOUDY SKIES LIKELY. LOOKS LIKE TEMPS MAY CREEP BACK TO A
COUPLE OR FEW DEGREES ABOVE NORMAL THROUGH MID WEEK.

LATEST MODELS SUGGEST IT MAY BE EVEN MILDER FRIDAY AND SATURDAY AS
UPPER RIDGING BUILDS IN FROM THE WEST. WITH THE SFC HIGH PUSHING ON
TO THE SOUTH...THE DOOR MAY OPEN BACK UP FOR SHOWER/STORM CHANCES.
NOT REALLY SEEING ANYTHING TO GRAB ONTO IN THE MODELS AT THIS POINT
THOUGH...SO KEPT THE FORECAST MAINLY DRY.

AVIATION/12Z TAFS/...A BLEND OF LOW CLOUDS AND FOG WILL AFFECT TAF
SITES EARLY THIS MORNING.  WL BE WATCHING COLD FRONT SLIDE ACROSS
SOUTHERN WI LATER THIS MORNING THROUGH MID-AFTERNOON.  BETTER CHANCE
FOR A 1-2 HOUR DURATION OF THUNDER AFFECTING EASTERN TAF SITES
DURING THE AFTN.  PERIOD OF MVFR CLOUDS MAY ACCOMPANY COOLER AIR
SAGGING SOUTH ACROSS SOUTHERN WI TONIGHT INTO EARLY MONDAY.

MARINE...STEEPENING LOW LEVEL LAPSE RATES ASSOCIATED WITH COLDER
AIR SAGGING SOUTH ACROSS LAKE MI TONIGHT BEHIND COLD FRONT WILL
RESULT IN GUSTY NORTH WINDS REACHING LAKE SURFACE.  THESE GUSTS WILL
LIKELY REACH SMALL CRAFT ADVISORY LEVELS FOR A TIME.  THE GUSTS WILL
DIMINISH ON MONDAY...HOWEVER HIGHER WAVE HEIGHTS WILL LINGER THROUGH
THE DAY.  POSTED SMALL CRAFT ADVISORY BEGINNING IN THE NORTH THIS
EVENING...AND IN THE SOUTH AROUND MIDNIGHT.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 1 AM TO 7 PM CDT MONDAY FOR LMZ645-646.

     SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM CDT MONDAY
     FOR LMZ643-644.

&&

$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
MONDAY THROUGH SATURDAY...DDV









AREA FORECAST DISCUSSION

NWS TALLAHASSEE FL

 321 AM EDT Tue Sep 3 2013

.NEAR TERM [Rest of Today]...
As of 07 UTC, TLH radar showed some showers beginning to develop
over the adjacent coastal waters of the Gulf of Mexico. Similar to
what was portrayed yesterday, the HRRR develops a considerable band
of convection near the coast between 10 UTC and 14 UTC, gradually
spreading it into our Florida zones through the morning hours. The
result in that scenario would be relatively high coverage of rain,
with some localized heavy rain. The raw GFS QPF portrays a similar
scenario, although the MAV PoPs tell a different story. Given the
recent favorable performance of the HRRR and its assessment of
current conditions, we have trended the PoP forecast towards the
past few runs of the HRRR (03-05z runs). This includes "likely"
(60-70%) PoPs for portions of the Florida Panhandle and Big Bend
during the morning hours, with a dry forecast north of a DHN-MGR
line in our Alabama and Georgia zones. By afternoon, there is more
uncertainty, but the current thinking is that morning convection
would stabilize our Florida zones leading to diminishing coverage
there, while additional thunderstorms develop along a weak front in
the northern parts of our area. The afternoon PoP is a general 50%.
Given that we have increased the expected rain and cloud cover in
the Florida Panhandle this morning, high temperatures were cut back
in those area to the upper 80s / around 90.

&&

.SHORT TERM [Tonight Through Thursday]...
Energy in the base of the eastern U.S. trough will slip south of the
area at the start of the period. While the trough will lose some
amplitude as its axis moves east of the area, the ridge over the
plains will only weakly ridge eastward. Overall, the forecast area
will remain in a regime of weak northwesterly flow aloft with low
level onshore flow. A surface ridge will remain south of the area
with a lee-side trough extending from the Carolina Piedmont into
central GA. A cold front over the Tennessee and Lower Mississippi
Valley will approach from the north on Thursday. PoPs and temps will
be close to climatology through the period. Organized severe weather
and flooding is not anticipated. However, as on most summer days, an
isolated strong to severe storm will be possible each afternoon.

&&

.LONG TERM [Thursday Night through Monday]...
Upper troughing will continue down the eastern seaboard through
Sunday before ridging builds in from the west early next week. The
aforementioned cold front will drop down into our CWA Thursday
becoming quasi-stationary Friday into Saturday. Will keep PoPs in
the chance category each day with temps near seasonal levels.

&&

.AVIATION...
[Through 06 UTC Wednesday] Most terminals are expected to have at
least brief MVFR restrictions this morning in fog or low stratus.
Some are likely to get to the IFR or LIFR range, especially around
sunrise. ECP and TLH may see some early thunderstorms, perhaps
developing near the coast as early as 12-13 UTC and then spreading
inland during the morning hours. ABY, DHN, and VLD may be affected
by scattered TSRA during the afternoon.


&&

.MARINE...
Outside of any thunderstorms, and with a weak pressure gradient in
place, light mainly onshore winds and minimal seas are expected over
the coastal waters this week.

&&

.FIRE WEATHER...
Relative humidity is expected to remain well above critical
thresholds for the next several days.

&&

.HYDROLOGY...
Forecast rainfall is not expected to cause any problems on area
rivers this week. Outside of the Suwannee River Basin, all rivers in
the forecast area remain in recession. The Aucilla River will
continue to fall slowly and is currently forecast to be below flood
stage at Lamont on Thursday. On the Suwannee, Wilcox at US19 has the
best chance of reaching flood stage late in the week. However, the
current forecast has it cresting just below this weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   89  74  92  73  92 / 60  20  40  20  30
Panama City   86  76  88  76  88 / 60  20  30  20  20
Dothan        92  71  91  72  91 / 50  20  30  20  30
Albany        93  73  92  73  91 / 50  20  30  20  30
Valdosta      93  73  93  74  93 / 50  20  40  20  30
Cross City    89  73  90  72  91 / 50  20  40  20  40
Apalachicola  86  76  88  75  89 / 70  20  30  20  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.

&&

$$

Near Term/Aviation/Fire Weather...Lamers
Long Term...Barry/Hernandez
Rest of Discussion...Wool





AREA FORECAST DISCUSSION

NWS PEACHTREE CITY GA

 357 AM EDT TUE SEP 3 2013


.SHORT TERM /TODAY THROUGH WEDNESDAY/...
DEEP UPPER TROUGH IN PLACE OVER THE EASTERN HALF OF THE COUNTRY...
WITH THE TROUGH AXIS PARALLEL TO THE SOUTHERN APPALACHIANS AT THE
START OF THE SHORT TERM. ASSOCIATED SURFACE FRONT CURRENTLY LOCATED
FROM NEAR THE UPPER OHIO VALLEY...STRETCHING THROUGH THE MID-SOUTH
AND TO NEAR THE RED RIVER AT AFD TIME. THE FRONT WILL WORK ITS WAY
SOUTHEAST THROUGH THE DAY...WITH DRIER AIR BEGINNING TO FILTER INTO
THE STATE FOR TONIGHT. SHORT-TERM GUIDANCE IS IN PRETTY GOOD
AGREEMENT WITH THE MASS FIELDS. NOT A LOT OF SYNOPTIC LIFT TO SPEAK
OF TODAY AS THE FRONT CONTINUES TO OCCLUDE...BUT THERE SHOULD BE AT
LEAST SOME SYNOPTIC CONTRIBUTION IN THE FORM OF WEAK DIVERGENCE
ALOFT /RIGHT ENTRANCE REGION OF THE BARELY-THERE UPPER JET/ AND OF
COURSE DPVA AHEAD OF THE SHORTWAVE ITSELF...BOTH OF THESE MAXIMIZED
ACROSS CENTRAL GEORGIA FOR THIS AFTERNOON.

OF IMMEDIATE CONCERN IS THE EVOLUTION OF CONVECTION THROUGH THE
EARLY MORNING HOURS. PRE-FRONTAL CONVECTION HAS FIRED ACROSS
NORTHWEST GEORGIA AT AFD TIME...AND IN SIMILAR MANNER TO YESTERDAY
MORNING THE CONVECTION FIRED ALONG AN INSTABILITY GRADIENT IN AN
AREA WHERE CIN IS MINIMIZED. LATEST RUNS OF THE HRRR ARE ACTUALLY
PICKING UP ON THIS AND PUSHING A CONVECTIVE COMPLEX ACROSS NORTH
GEORGIA BETWEEN NOW AND APPROXIMATELY 13Z. BASED ON WHAT HAPPENED
LAST NIGHT...THIS IS NOT AT ALL AN UNREASONABLE SOLUTION...AND OTHER
HIRES GUIDANCE POINTING TO THE SAME THING. ARW MEMBERS NOT QUITE SO
PRONOUNCED AS THE NMM THOUGH. HRRR HAS NOT BEEN DOING WELL THE PAST
FEW DAYS BUT PERHAPS IT HAS FINALLY CAUGHT UP...AND IN ANY CASE THE
OVERALL PATTERN IS SUPPORTIVE OF DEVELOPMENT OF THESE OVERNIGHT
CONVECTIVE COMPLEXES. AS WAS THE CASE YESTERDAY...WHATEVER DOES
DEVELOP ACROSS NORTH GEORGIA EARLY THIS MORNING WILL LIKELY
DISSIPATE BY MID-MORNING /AFTER SUNRISE/ AS MIXING INCREASES.
HOWEVER...IF SUCH A CONVECTIVE COMPLEX DEVELOPS /AS IT DID
YESTERDAY/...IT WILL LIKELY WREAK HAVOC ON HIGH TEMPS TODAY /AS IT
DID YESTERDAY/. AT THIS POINT IT IS NEARLY IMPOSSIBLE TO TRY TO PIN
DOWN THOSE DETAILS BUT SUFFICE IT TO SAY THAT WE COULD SEE SOME BIG
BUSTS AGAIN TODAY /AS WE DID YESTERDAY/.

CAPES INCREASE TO BETWEEN 1500-2000 J/KG THIS AFTERNOON AHEAD OF THE
FRONT...MAINLY FROM APPROXIMATELY THE ATLANTA METRO AREA AND POINT
SOUTH. EXPECT CONVECTION TO FIRE AGAIN THIS AFTERNOON WITH BEST
COVERAGE ACROSS CENTRAL GEORGIA BUT ISOLATED TO SCATTERED CONVECTION
POSSIBLE UP INTO THE METRO AREA. EXPECT THE BULK IF NOT ALL OF THE
ACTIVITY TO DIE DOWN BY 06Z AND THUS HAVE NO POPS ACROSS THE AREA
OVERNIGHT. THE FRONT WILL CONTINUE TO SAG SOUTH AND WE SHOULD SEE A
NOTICEABLE DIFFERENCE IN LOW TEMPS BETWEEN WHAT WE HAVE THIS MORNING
AND TONIGHT...GENERALLY DOWN 3-5 DEGREES.

FRONT SHOULD STALL SOMEWHERE ACROSS THE AREA ON WEDNESDAY...KEEPING
THE CHANCE FOR CONVECTION ACROSS CENTRAL GEORGIA MAINLY DURING THE
AFTERNOON. INFLUENCE OF DRIER AIR WILL BE FELT ACROSS NORTH GEORGIA
BUT NO REAL CAA ALOFT TO SPEAK OF SO DO NOT THINK THAT TEMPS
WEDNESDAY WILL BE MUCH IF AT ALL COOLER THAN THOSE TODAY. /AND
ACTUALLY IF WE HAVE RAIN-COOLED AIR FROM CONVECTION THIS MORNING
MESSING WITH TEMPS TODAY...THEN WEDNESDAY COULD ACTUALLY BE WARMER./
ALL THAT SAID...WENT WITH A GENERAL BIAS-ADJUSTED BLEND.


TDP


.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

MODELS CONSISTENT IN KEEPING DRY AIR ACROSS NORTH GEORGIA THROUGH
THE END OF THE WEEK AS THE FRONTAL BOUNDARY STALLS JUST SOUTH OF
THE CWA. DRYING ALOFT AND LOW PRECIPITABLE WATER SHOULD KEEP
CONVECTION OUT OF MUCH OF THE CWA THROUGH THURSDAY NIGHT...EXCEPT
FOR SLIGHT CHANCE AFTERNOON AND EVENING ALONG THE LAST ROW OR TWO
OF COUNTIES SOUTH OF COLUMBUS TO MACON. MOISTURE BEGINS SPREADING
BACK INTO THE FORECAST AREA ON FRIDAY AS LOW LEVEL WINDS TURN TO
THE EAST AND SOUTHEAST. HOWEVER WITH UPPER RIDGE BUILDING OVER THE
SOUTHEAST STATES THROUGH THE END OF THE PERIOD...EXPECTING ONLY
LOW CHANCE OR SLIGHT CHANCE AFTERNOON AND EVENING THUNDERSTORMS
ACROSS THE AREA.


41


&&


AVIATION...
06Z UPDATE...
VFR AT TAF TIME BUT EXPECT MVFR FOG TO DEVELOP OVERNIGHT. WILL
PROBABLY SEE FEW-SCT IFR TO MVFR CLOUDS WITH BKN MID LEVEL...BUT
CANNOT RULE OUT A BRIEF IFR CIG SO HAVE INCLUDED THAT IN TEMPO
GROUPS. CIGS LIFTING AFTER 13Z OR SO. BEST CHANCE THUNDER AT
CSG/MCN BUT DID INCLUDE VCSH FOR NORTHERN TAFS THIS AFTERNOON. FOR
NOW...VFR EXPECTED THROUGH THE END OF THE PERIOD. W TO NW WINDS
BETWEEN 5-10KT THIS AFTERNOON...NEARLY CALM OVERNIGHT.

//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON MORNING CIGS.
MEDIUM ON AFTERNOON CONVECTION.
HIGH ON WINDS.

TDP

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  68  89  66 /  30  20  10   5
ATLANTA         88  70  89  67 /  30  10   5   5
BLAIRSVILLE     84  61  84  61 /  40  10   5   5
CARTERSVILLE    89  65  88  64 /  40  10   5   5
COLUMBUS        91  72  91  69 /  30  20  20  10
GAINESVILLE     87  68  87  67 /  40  10  10   5
MACON           91  69  92  68 /  30  20  20  10
ROME            88  65  89  63 /  40   5   5   5
PEACHTREE CITY  89  66  88  63 /  30  20   5   5
VIDALIA         90  72  91  71 /  40  20  20  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...TDP
LONG TERM....41
AVIATION...TDP






AREA FORECAST DISCUSSION

NWS DES MOINES IA

 340 AM CDT TUE SEP 3 2013

.SHORT TERM.../TODAY/...
ISSUED AT 336 AM CDT TUE SEP 3 2013

BENIGN FORECAST ON TAP FOR TODAY.  WE WILL HAVE SOME FOG TO DEAL
WITH THIS MORNING.  SOUNDINGS SHOWING A VERY SHALLOW LAYER OF
MOISTURE WHICH IS PRODUCING PATCHY TO AREAS OF FOG REDUCING
VISIBILITIES TO BETWEEN A QUARTER TO A HALF MILE IN A FEW SPOTS.
VISIBILITIES GENERALLY BETWEEN 3 AND 5 MILES ELSEWHERE THAT FOG
EXISTS.  THE FOG SHOULD BE VERY SHALLOW AND AS SUCH SHOULD BURN OFF
QUICKLY WITH SUNRISE.  FOR THE REST OF TODAY...SURFACE HIGH PRESSURE
WILL SLOWLY SHIFT EAST THROUGH TODAY ALLOWING LIGHT SURFACE WINDS TO
SHIFT TO THE SOUTH.  AIRMASS WILL STILL BE DRY WITH DEWPOINTS
STARTING OUT IN THE 40S AND 50S AND ONLY REACHING MID 50S BY LATE
AFTERNOON.  ALOFT HIGH PRESSURE OVER THE ROCKIES/HIGH PLAINS WILL
KEEP THE AREA IN A NW FLOW.  THE MODELS DO HINT AT A SHORTWAVE
APPROACHING THE NW VERY LATE THIS AFTERNOON BUT LIKELY NOT AFFECTING
OUR FORECAST AREA UNTIL THE EVENING.  I DID RAISE HIGHS TODAY GIVEN
AMPLE SUN AND NOT A LOT OF MOISTURE AROUND BUT THIS IS TEMPERED BY
THE NW FLOW ALOFT AND SHALLOW WARMING WITH LITTLE MIXING.  WIND
SPEEDS THROUGH 800 MB ARE BARELY 10 KTS.  JUST A NICE EARLY
SEPTEMBER DAY.


.LONG TERM.../TONIGHT THROUGH MONDAY/...
ISSUED AT 336 AM CDT TUE SEP 3 2013

PATTERN WILL REMAIN ESSENTIALLY UNCHANGED THROUGH THE WEEK WITH
TEMPS THE PRIMARY CONCERN...FOLLOWED BY VERY SUBTLE PRECIP CHANCES.
TEMPS WILL CONTINUE TO WARM INTO WED AS H85/H7 RIDGE DRIFTS EAST AND
CURRENT SURFACE HIGH BECOMES LESS DOMINATE.  A BRIEF RESURGENCE OF
A GREAT LAKES HIGH MAY BACK DOOR SOME SLIGHTLY COOLER TEMPERATURES
INTO IA BY THU...BUT THIS WILL BE SHORT LIVED AS RETURN FLOW
INCREASES ONCE AGAIN TO END THE WORK WEEK. NAM DRAWS IN COOLER AND
DRIER AIRMASS BUT THIS IS SOMEWHAT OF AN OUTLIER SO STAYED CLOSER
TO CONSENSUS. HAVE ALSO INCLUDED A SMALL PATCH OF SLIGHT CHANCES
WEST CENTRAL WED NIGHT IN SOME WEAK THERMODYNAMIC FORCING...BUT
SOUNDINGS SUGGEST ANYTHING THAT DOES FORM WOULD BE QUITE WEAK AND
ELEVATED. 305/310K ISENT ANALYSIS SHOWS VERY WEAK LIFT IN LIGHT WINDS.

MUCH ABOVE NORMAL TEMPERATURES BECOME THE MAIN THEME HEADING INTO
THE WEEKEND AND EARLY NEXT WEEK AS UPPER LEVEL RIDGE CROSSES THE
CENTRAL PLAINS INTO THE MID MS VALLEY.  THIS WILL BOOST TEMPERATURES
EVEN FURTHER ABOVE NORMAL WITH HIGHS CREEPING THROUGH THE 90S.
PRECIP CHANCES GRADUALLY INCREASE LATE IN THE WEEKEND AS WEAK
SHORT WAVES TOP THE RIDGE AND POTENTIALLY INDUCE A WEAK
BAROCLINIC/FRONTOGENETICAL ZONE NW-SE ACROSS NERN IA. STRONGER
WARM ADVECTION SURGE LIFTS INTO THE UPPER MS VALLEY SUN
NIGHT...POSSIBLY GLANCING NRN IA BUT ALSO LIKELY INTRODUCING THE
WARMEST TEMPS OF THE PERIOD. HAVE NUDGED READINGS HIGHER...BUT
THESE MAY NOT EVEN BE WARM ENOUGH CONSIDERING MIXING AND FAVORABLE
SSW WINDS BY MON. NRN PLAINS SHORT WAVE WILL EVENTUALLY INCREASE
KINEMATIC FORCING INTO THE SIOUXLAND AREA BY LATE MON WHICH WOULD
ALSO BE COINCIDENT WITH THE ASSOCIATED FRONTAL BOUNDARY LEADING TO
SOMEWHAT BETTER PRECIP CHANCES. BEST POTENTIAL MAY BE JUST BEYOND
THE VALID PERIOD INTO MON NIGHT HOWEVER WITH FROPA EVENTUALLY DROPPING
TEMPS BACK CLOSER TO NORMAL INTO NEXT WEEK.

&&

.AVIATION...03/06Z
ISSUED AT 1135 PM CDT MON SEP 2 2013

MVFR TO IFR FOG POSSIBLY OVER THE NORTH AND NORTHEAST TAF AREAS
AND HAVE FOD/MCW/ALO DOWN TO IFR BY 09Z AS DEW POINT DEPRESSION IS
UNDER 2 WITH LIGHT WINDS. THE LATEST HRRR AND HOPWRF SHOW
VISIBILITY DROPPING BY 09Z THROUGH 12Z...AND LEANED TOWARD THIS
TIMING. LOW CONFIDENCE WITH ANY FOG AT DSM AND IF FOG DOES DEVELOP
IT WILL BE SHORTLY BEFORE SUNRISE AND NOT PERSIST TOO LONG.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...FAB
LONG TERM...SMALL
AVIATION...PODRAZIK





AREA FORECAST DISCUSSION

NWS DES MOINES IA

 1142 PM CDT MON SEP 2 2013

...UPDATED AVIATION DISCUSSION...

.SHORT TERM.../TONIGHT /...
ISSUED AT 325 PM CDT MON SEP 2 2013

HIGH PRESSURE EXTENDING FROM NRN MN INTO KS WILL SETTLE OVER THE
STATE TONIGHT.  WINDS WILL DIMINISH WITH SUNSET AND BE NEAR CALM
OVERNIGHT  EXPECT TO SEE AREAS OF FOG DEVELOP TONIGHT.  NOT ENOUGH
CONFIDENCE FOR ANY HEADLINES...BUT WILL HAVE FOG MENTIONED IN THE
WORDING OF THE FORECAST. TEMPS TONIGHT WILL BE IN THE 40S FOR MUCH
OF THE CWA...SOME LOW TO MID 50S IN THE SOUTH.

.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 325 PM CDT MON SEP 2 2013

MAJORITY OF EXTENDED STILL LOOKS TRANQUIL WITH A GRADUAL WARMING
TREND. NORTHWEST FLOW PATTERN STILL EXPECTED ALOFT WITH LARGE
AMPLIFIED RIDGING ACROSS THE WESTERN US AND SFC HIGH PRESSURE
DOMINATING THE REGION TUESDAY INTO EARLY WEDNESDAY. WEAK SHORTWAVE
TROUGH STILL ON TAP TO DROP SOUTHEASTWARD THROUGH IOWA WEDNESDAY
INTO WEDNESDAY NIGHT. MOISTURE CONTINUES TO LOOK LIMITED WITH THE
BEST THETA-E ADVECTION TO THE WEST OF THE CWA NOW. THEREFORE HAVE
REMOVED ALL POPS FOR WEDNESDAY AND STUCK WITH MAINLY INCREASED CLOUD
COVER. UPPER RIDGE TO BREAK DOWN TOWARD THE WEEKEND...WITH AN UPPER
TROUGH MOVING ASHORE INTO THE NORTHERN ROCKIES SUNDAY. MOISTURE
RETURN TO INCREASE IN SOUTHERLY FLOW WITH WAA AND THETA-E ADVECTION
KICKING IN WITH PASSAGE OF A WEAK WARM FRONT SUNDAY. MAY SEE SOME
CHANCE FOR THUNDERSTORMS ACROSS THE NORTHERN CWA SUNDAY INTO SUNDAY
NIGHT. UPPER TROUGH TO TRACK EASTWARD ACROSS THE NORTHERN US AND
INTO THE GREAT LAKES REGION MONDAY INTO TUESDAY. ASSOCIATED COLD
FRONT TO DROP THROUGH THE CWA LATE MONDAY INTO MONDAY NIGHT. THIS
WILL PROVIDE ANOTHER CHANCE FOR PRECIPITATION ACROSS THE MAINLY THE
NORTHERN CWA MONDAY NIGHT. H85 TEMPS CLIMB INTO THE LOWER/MID 20S
CELSIUS AHEAD OF THE FRONT FRIDAY INTO SATURDAY/SUNDAY...SO HAVE
TEMPS WARMING BACK INTO THE UPPER 80S TO LOW 90S. ANOTHER
COOLER...DRY PERIOD SETTING UP BEYOND THE CURRENT FORECAST PERIOD
TOWARD THE MIDDLE TO END OF NEXT WEEK.

&&

.AVIATION...03/06Z
ISSUED AT 1135 PM CDT MON SEP 2 2013

MVFR TO IFR FOG POSSIBLY OVER THE NORTH AND NORTHEAST TAF AREAS
AND HAVE FOD/MCW/ALO DOWN TO IFR BY 09Z AS DEW POINT DEPRESSION IS
UNDER 2 WITH LIGHT WINDS. THE LATEST HRRR AND HOPWRF SHOW
VISIBILITY DROPPING BY 09Z THROUGH 12Z...AND LEANED TOWARD THIS
TIMING. LOW CONFIDENCE WITH ANY FOG AT DSM AND IF FOG DOES DEVELOP
IT WILL BE SHORTLY BEFORE SUNRISE AND NOT PERSIST TOO LONG.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...MS SEP13
LONG TERM...BEERENDS
AVIATION...PODRAZIK





AREA FORECAST DISCUSSION

NWS JACKSON KY

 259 AM EDT TUE SEP 3 2013

.UPDATE...
ISSUED AT 1218 AM EDT TUE SEP 3 2013

LINE OF SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ALONG THE FAR
SOUTHERN AND EASTERN RELMS OF THE CWA. WITH A FEW MORE SHOWERS
DEVELOPING BEHIND MAIN LINE...WENT AHEAD AND ADDED IN A FEW MORE
HOURS OF SCT AND ISOLATED POPS BEHIND THE INITIAL LINE OF HIGHER
POPS. STILL EXPECT MUCH OF THE REGION TO BE CLEAR OVER THE NEXT 2 TO
3 HOURS. ALSO LOADED IN LATEST TEMPERATURE AND WIND OBSERVATIONS TO
MAKE SURE ONGOING FORECAST WAS MATCHING UP WELL WITH CURRENT
CONDITIONS.

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 NIGHT THROUGH MONDAY)
ISSUED AT 259 AM EDT TUE SEP 3 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 SUNDAY AND
MONDAY AFTERNOONS.

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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 219 AM EDT TUE SEP 3 2013

CONVECTION ASSOCIATED WITH A PASSING COLD FRONT IS CONTINUING TO MAKE
ITS WAY OUT OF EASTERN KY TONIGHT. IN ITS WAKE...A BAND OF CLOUDS
AND LOW LEVEL MOISTURE REMAIN ACROSS SOUTHEASTRN KY...EXITING THE
REGION AT A MUCH SLOWER RATE. JUST TO OUR NE...LATEST OBSERVATIONS ARE
SHOWING CONSIDERABLE DRYING. THIS BRINGS SOME UNCERTAINTY TO THE
FORECAST FOR THE TAF SITES CONCERNING THE DEVELOPMENT OF FOG OVERNIGHT.
IF THE LOWER DEW POINTS UPSTREAM AND DRY AIR ARE ABLE TO MAKE IT INTO
THE REGION THERE SHOULD BE NO FOG. HOWEVER IF THIS DRY AIR MOVES IN
AND TRAPS THE MOISTURE NEAR THE SURFACE AS MANY OF THE MODELS AND
GUIDANCE ARE PREDICTING...MUCH OF THE REGION COULD SEE SOME DEGREE OF
BR. THAT BEING SAID...FORECASTED TOWARDS FOG BUT DID NOT GO QUITE AS
LOW AS GUIDANCE SINCE DRY AIR WILL PROBABLY PLAY A BIGGER ROLE THAN
WHAT THE MODELS ARE PICKING UP ON. EXPECT KJKL AND KSME TO STAY MVFR
OR GREATER WITH THE N/NE WINDS COMING IN...WHILE LONDON COULD DROP
DOWN LOWER TO IFR /WITH POSSIBLE LIFR. WILL CONTINUE TO MONITOR
ONGOING CONDITIONS AND AMMEND AS NEEDED. ONCE FOG MIXES OUT AND LIFTS
IN THE MORNING...HIGH PRESSURE OVERHEAD SHOULD MAKE FOR VFR
CONDITIONS THROUGH THE REMAINDER OF THE TAF PERIOD.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JMW
SHORT TERM...HAL
LONG TERM...GEOGERIAN/DUSTY
AVIATION...JMW








AREA FORECAST DISCUSSION

NWS JACKSON KY

 220 AM EDT TUE SEP 3 2013

.UPDATE...
ISSUED AT 1218 AM EDT TUE SEP 3 2013

LINE OF SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ALONG THE FAR
SOUTHERN AND EASTERN RELMS OF THE CWA. WITH A FEW MORE SHOWERS
DEVELOPING BEHIND MAIN LINE...WENT AHEAD AND ADDED IN A FEW MORE
HOURS OF SCT AND ISOLATED POPS BEHIND THE INITIAL LINE OF HIGHER
POPS. STILL EXPECT MUCH OF THE REGION TO BE CLEAR OVER THE NEXT 2 TO
3 HOURS. ALSO LOADED IN LATEST TEMPERATURE AND WIND OBSERVATIONS TO
MAKE SURE ONGOING FORECAST WAS MATCHING UP WELL WITH CURRENT
CONDITIONS.

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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 219 AM EDT TUE SEP 3 2013

CONVECTION ASSOCIATED WITH A PASSING COLD FRONT IS CONTINUING TO MAKE
ITS WAY OUT OF EASTERN KY TONIGHT. IN ITS WAKE...A BAND OF CLOUDS
AND LOW LEVEL MOISTURE REMAIN ACROSS SOUTHEASTRN KY...EXITING THE
REGION AT A MUCH SLOWER RATE. JUST TO OUR NE...LATEST OBSERVATIONS ARE
SHOWING CONSIDERABLE DRYING. THIS BRINGS SOME UNCERTAINTY TO THE
FORECAST FOR THE TAF SITES CONCERNING THE DEVELOPMENT OF FOG OVERNIGHT.
IF THE LOWER DEW POINTS UPSTREAM AND DRY AIR ARE ABLE TO MAKE IT INTO
THE REGION THERE SHOULD BE NO FOG. HOWEVER IF THIS DRY AIR MOVES IN
AND TRAPS THE MOISTURE NEAR THE SURFACE AS MANY OF THE MODELS AND
GUIDANCE ARE PREDICTING...MUCH OF THE REGION COULD SEE SOME DEGREE OF
BR. THAT BEING SAID...FORECASTED TOWARDS FOG BUT DID NOT GO QUITE AS
LOW AS GUIDANCE SINCE DRY AIR WILL PROBABLY PLAY A BIGGER ROLE THAN
WHAT THE MODELS ARE PICKING UP ON. EXPECT KJKL AND KSME TO STAY MVFR
OR GREATER WITH THE N/NE WINDS COMING IN...WHILE LONDON COULD DROP
DOWN LOWER TO IFR /WITH POSSIBLE LIFR. WILL CONTINUE TO MONITOR
ONGOING CONDITIONS AND AMMEND AS NEEDED. ONCE FOG MIXES OUT AND LIFTS
IN THE MORNING...HIGH PRESSURE OVERHEAD SHOULD MAKE FOR VFR
CONDITIONS THROUGH THE REMAINDER OF THE TAF PERIOD.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JMW
SHORT TERM...HAL
LONG TERM...GEOGERIAN
AVIATION...JMW







AREA FORECAST DISCUSSION

NWS JACKSON KY

 1219 AM EDT TUE SEP 3 2013

.UPDATE...
ISSUED AT 1218 AM EDT TUE SEP 3 2013

LINE OF SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ALONG THE FAR
SOUTHERN AND EASTERN RELMS OF THE CWA. WITH A FEW MORE SHOWERS
DEVELOPING BEHIND MAIN LINE...WENT AHEAD AND ADDED IN A FEW MORE
HOURS OF SCT AND ISOLATED POPS BEHIND THE INITIAL LINE OF HIGHER
POPS. STILL EXPECT MUCH OF THE REGION TO BE CLEAR OVER THE NEXT 2 TO
3 HOURS. ALSO LOADED IN LATEST TEMPERATURE AND WIND OBSERVATIONS TO
MAKE SURE ONGOING FORECAST WAS MATCHING UP WELL WITH CURRENT
CONDITIONS.

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...JMW
SHORT TERM...HAL
LONG TERM...GEOGERIAN
AVIATION...JJ







AREA FORECAST DISCUSSION

NWS GRAY ME

 307 AM EDT TUE SEP 3 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST TODAY...
PROVIDING THE FOCUS FOR THUNDERSTORMS AGAIN THIS AFTERNOON. THE
FRONT WILL SWEEP OUT ALL THE WET AND HUMID WEATHER BY TONIGHT. A
SECOND COLD FRONT COMES THROUGH WEDNESDAY NIGHT...PROVIDING A
BRIEF SHOT OF MUCH COOLER AIR FOR THE END OF THE WEEK. HIGH
PRESSURE WILL BUILD ACROSS THE REGION LATE THURSDAY THROUGH
SATURDAY. ANOTHER COLD FRONT WILL CROSS NEW ENGLAND SATURDAY NIGHT
AND SUNDAY FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW CLOUDS AND FOG WILL SLOWLY MIX OUT ACROSS THE REGION THIS
MORNING. EASTERN AREAS...ESPECIALLY NEAR THE COASTLINE...WILL BE
SLOW TO IMPROVE. IN THE MEANTIME...THE LATEST HRRR MODEL RUN
CONTINUES TO SHOW SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING OVER
EASTERN NEW HAMPSHIRE AROUND 17Z. THIS PRECIPITATION IS IN
ASSOCIATION WITH AN APPROACHING COLD FRONT. WITH APPROACHING UPPER
LEVEL TROUGH...WIND MAX AND MODEST INSTABILITY...EXPECT A FEW
STORMS TO CONTAIN DAMAGING WINDS OR HAIL.

HAVE THEREFORE ADDED ENHANCED WORDING TO THE FORECAST PACKAGE.
THUNDERSTORMS WILL CONTINUE UNTIL THIS EVENING...HOWEVER SOME OF
THE CONVECTIVE ACTIVITY WILL HAVE A CHALLENGING TIME MAKING IT
THROUGH ANY REMAINING LOW CLOUDS AND FOG ALONG THE MIDCOAST.

LOOK FOR 70S IN MOST AREAS...HOWEVER SOUTHERN NEW HAMPSHIRE MAY
TIP THE 80 DEGREE MARK.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
THE PRECIPITATION EXITS THE REGION THIS EVENING AS THE COLD FRONT
MOVES EAST. DRIER AIR WILL FILTER INTO THE FORECAST AREA FROM THE
WEST. HOWEVER...PLENTY OF LOW LEVEL MOISTURE FROM RECENT HEAVY
RAINS WILL ALLOW FOR MORE PATCHY FOG TO DEVELOP.

BY WEDNESDAY...THE UPPER LEVEL TROUGH WILL PUSH EAST OF THE
REGION...AND WE WILL BE IN BETWEEN SYSTEMS. A STRONG COLD FRONT
WILL APPROACH FROM THE WEST...BUT MUCH OF THE CLOUDINESS AND ANY
PRECIPITATION WILL HOLD OFF UNTIL AFTER DARK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN THROUGH THE
FORECAST PERIOD. THE UPPER TROUGH LINGERS ACROSS THE REGION
THROUGH THE UPCOMING WEEKEND BEFORE THE UPSTREAM RIDGE ACROSS THE
INTERMOUNTAIN WEST FINALLY WEAKENS...AND THE FLOW BECOMES MORE
ZONAL ACROSS THE FORECAST AREA. WE BEGIN THE PERIOD WITH A
RELATIVELY DEEP TROUGH ACROSS THE AREA...AND A SURFACE COLD FRONT
MAKING ITS WAY SOUTHWARD ACROSS THE REGION WEDNESDAY NIGHT AND
EARLY THURSDAY. THIS FRONT WILL USHER BELOW NORMAL TEMPERATURES
INTO THE AREA FOR THURSDAY AND FRIDAY AS HIGH PRESSURE BUILDS
SOUTH AND EAST FROM THE GREAT LAKES. A RETURN FLOW AROUND THE
HIGH WILL INTRODUCE MILDER AIR INTO THE REGION SATURDAY. ANOTHER
SHORTWAVE WILL DRIVE A STRONG COLD FRONT ACROSS THE AREA SATURDAY
NIGHT AND SUNDAY WITH HIGH PRESSURE AND DRY AIR TO FOLLOW FOR
MONDAY.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...AREAS OF LOW CLOUDINESS AND FOG WILL SLOWLY MIX OUT
OVER THE REGION THIS MORNING...WITH THE LAST AREA TO CLEAR BEING EASTERN
AREAS THIS MORNING...ESPECIALLY NEAR THE COASTLINE. HOWEVER...THE
IMPROVEMENT WILL BE BRIEF WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AFT NOONTIME TODAY FROM WEST TO EAST. THE LOCALLY
STRONG SHOWERS AND STORMS WILL END THIS EVENING...FOLLOWED BY MORE
IFR AND ISOLATED LIFR CONDITIONS IN DEVELOPING FOG. VFR CONDITIONS
ON WEDNESDAY.

LONG TERM...

WED NIGHT - THU...SCT MVFR IN SHOWERS AND TSTMS.

&&

.MARINE...
SHORT TERM...A COLD FRONT WILL CROSS THE WATERS ON TODAY WITH
THUNDERSTORMS POSSIBLE AGAIN. WINDS AND SEAS WILL BE FAIRLY QUIET
OUTSIDE OF THUNDERSTORMS.

LONG TERM...

FRI NIGHT - SAT...WINDS AND SEAS MAY APPROACH SMALL CRAFT.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 206 AM EDT TUE SEP 3 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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 205 AM EDT TUE SEP 3 2013

HIGH PRES CURRENTLY OVER THE UPPER MISSISSIPPI VALLEY WILL STEADILY
MOVE SE OVER THE NEXT 24HRS WHILE A COLD FRONT DROPS SE...REACHING
LAKE SUPERIOR THIS EVENING. THE DRY AIR MASS ASSOCIATED WITH THE
HIGH WILL CONTINUE TO DOMINATE...RESULTING IN MAINLY CLEAR SKIES/VFR
CONDITIONS AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD. HOWEVER...
TYPICAL OF THESE QUIET/RADIATIONAL COOLING NIGHTS...PATCHES OF
MAINLY SHALLOW FOG WILL AFFECT KIWD OVERNIGHT...RESULTING IN OCNL
WIDE VIS FLUCTUATIONS. UNDER TIGHTENING PRES GRADIENT JUST AHEAD OF
APPROACHING COLD FRONT...INCREASING WINDS ABOVE DEVELOPING NOCTURNAL
INVERSION MAY RESULT IN LLWS THIS EVENING AT ALL TERMINALS.
&&

.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 UNTIL 6 AM EDT EARLY THIS MORNING FOR
     MIZ005-006.

LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC







AREA FORECAST DISCUSSION

NWS LAS VEGAS NV

 1030 PM PDT MON SEP 2 2013

.SYNOPSIS...A VERY SLOW DRYING TREND IS EXPECTED THROUGH MUCH OF THE
WEEK...WITH CHANCES FOR SHOWERS AND THUNDERSTORMS GRADUALLY
DECREASING. TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL IN MOST
AREAS.
&&

.UPDATE...SHOWERS/THUNDERSTORMS CONTINUING OVER SOUTHERN PORTIONS OF
THE AREA WITH NEW ACTIVITY DEVELOPING OVER CENTRAL AND SOUTHERN
MOHAVE AND SOUTHERN CLARK COUNTIES. THE ACTIVITY IN CLARK SEEMS TO
BE GENERATING ALONG AN OUTFLOW BOUNDARY AND THE STORMS ARE NOT
REALLY LASTING THAT LONG WHEN THEY DO DEVELOP. HOWEVER...THE STORMS
IN MOHAVE COUNTY LOOK TO BE DEVELOPING AHEAD OF A DISTURBANCE THAT
SHOWS UP NICELY IN BOTH THE RUC AND NAM12 MODELS. THESE STORMS ARE
LIKELY TO CONTINUE DEVELOPING NORTHWARD OVER THE NEXT FEW HOURS AND
COVERAGE MAY ALSO CONTINUE TO EXPAND. BEHIND THIS DISTURBANCE SKIES
WERE GENERALLY CLEARING AND THAT CLEARING WILL EVENTUALLY WORK INTO
MOHAVE COUNTY OVERNIGHT.
&&

.PREV DISCUSSION...
139 PM PDT MON SEP 2 2013

.SHORT TERM...SATELLITE AND AREA RADARS SHOWED THUNDERSTORMS MAINLY
CONFINED TO THE HIGHER TERRAIN OF LINCOLN...CLARK AND NORTHERN
MOHAVE COUNTIES THIS AFTERNOON. THESE ARE THE AREAS IN THE FLASH
FLOOD WATCH...SO THE WATCH LOOKS GOOD AT THIS TIME AND PLAN TO LEAVE
IT AS IS. THE MAIN FEATURE OF INTEREST IS THE MID LEVEL CIRCULATION
APPROACHING SOUTHERN CALIFORNIA FROM THE SOUTH. THIS FEATURE APPEARS
TO BE COMPRISED OF A PRE EXISTING UPPER LEVEL LOW WHICH WAS OFF THE
BAJA COAST PLUS PART OF THE CIRCULATION FROM THE REMNANTS OF
TROPICAL STORM KIKO. THIS FEATURE IS EXPECTED TO TRACK NORTH ACROSS
SOUTHEAST CALIFORNIA TONIGHT AND TUESDAY MORNING. WITH DEEP MOISTURE
STILL IN PLACE...BELIEVE THIS FEATURE SHOULD BE ABLE TO PRODUCE AT
LEAST LIGHT RAIN OVER THE WESTERN ZONES...SO RAISED POPS OVERNIGHT.
REMNANT ENERGY COULD LINGER OVER THE NORTHERN AND WESTERN ZONES
TUESDAY AFTERNOON...SO KEPT HIGHER POPS THERE. THE MAIN CONCERN WITH
THUNDERSTORMS CONTINUES TO BE FLASH FLOODING...BUT COVERAGE IS NOT
EXPECTED TO BE HIGH ENOUGH ON TUESDAY TO JUSTIFY EXTENDING THE FLASH
FLOOD WATCH. EXPECT LITTLE CHANGE IN TEMPERATURES FROM TODAY TO
TUESDAY...EXCEPT IN AREAS WHERE THUNDERSTORMS OCCUR.

.LONG TERM...WEDNESDAY THROUGH MONDAY...NO SIGNIFICANT CHANGES TO
THE LONG TERM FORECAST THIS AFTERNOON. THE WEATHER WILL BE DOMINATED
BY A TROUGH OF LOW PRESSURE OVER THE PACIFIC NORTHWEST...AN AREA OF
HIGH PRESSURE OVER THE ROCKIES/CENTRAL U.S...AND WHATEVER LOCAL
MOISTURE IS LEFT OVER AND RECYCLED EACH DAY. THIS LOOKS TO BRING
MAINLY A DIURNAL CYCLE OF SHOWERS/THUNDERSTORMS TO THE REGION. NO
TWO MODELS APPEAR TO AGREE ON A SIGNIFICANT FEATURE THAT WOULD BRING
ADDITIONAL DYNAMICS TO THE AREA. THE BEST CHANCES OF SCATTERED
CONVECTION WILL BE OVER THE HIGHER TERRAIN ACROSS THE EASTERN
CWA...WITH ISOLATED CHANCES IN THE VALLEYS AND BASINS. OVERALL THERE
APPEARS TO BE A GRADUAL DRYING TREND THROUGH THE PERIOD. THIS IS
MOST SIGNIFICANT OVER THE WEEKEND WHEN THE TROUGH PUSHES
ONSHORE...LIKELY BRINGING SOME ADDITIONAL DRYING FROM THE NORTHWEST.
TEMPERATURES WILL LIKELY REMAIN JUST ABOVE NORMAL THROUGH THE
PERIOD.

.AVIATION...FOR MCCARRAN...THUNDERSTORM CHANCES AT THE TERMINAL WILL
BE LOW THROUGH THE WEEK...ESPECIALLY FROM WEDNESDAY ONWARD. THERE
WILL BE THUNDERSTORM CHANCES IN ALL APPROACH CORRIDORS TUESDAY...AND
CHANCES SHOULD BE LIMITED TO THE MORMON MESA AND PEACH SPRINGS
CORRIDORS BEGINNING ON WEDNESDAY. WINDS WILL GENERALLY FOLLOW NORMAL
DIURNAL PATTERNS...EXCEPT OUTFLOW BOUNDARIES FROM THUNDERSTORMS
COULD BRING PERIODS OF GUSTY AND SHIFTING WINDS.

FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...CHANCES FOR THUNDERSTORMS WILL CONTINUE AREAWIDE
THROUGH TUESDAY...THEN DECREASE FROM THE WEST BEGINNING ON
WEDNESDAY. WINDS WILL GENERALLY FOLLOW NORMAL DIURNAL
PATTERNS...EXCEPT OUTFLOW BOUNDARIES FROM THUNDERSTORMS COULD BRING
PERIODS OF GUSTY AND SHIFTING WINDS.
&&

.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&

$$

UPDATE...JENSEN
PREV DISCUSSION...MORGAN/WOLCOTT

FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:

HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER









AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1230 AM CDT TUE SEP 3 2013

.UPDATE...
ISSUED AT 1230 AM CDT TUE SEP 3 2013

SURFACE HIGH PRESSURE OVER IOWA WILL CONTINUE TO MOVE SOUTH AND EAST
TONIGHT. SURFACE LOW PRESSURE OVER MONTANA AND WYOMING IS FORECAST
TO APPROACH THE WESTERN DAKOTAS BY DAYBREAK. CURRENT FORECAST IS ON
TRACK WITH LIGHT SOUTHEAST WINDS...AND TEMPERATURE TREND ON TRACK
WITH MIDNIGHT TEMPERATURES IN THE 50S OVER MOST OF THE JAMES RIVER
BASIN TO THE LOWER 70S FAR WEST. LOW TEMPERATURES TONIGHT SHOULD
REACH THE LOWER 50S EASTERN PORTIONS OF CENTRAL NORTH DAKOTA TO THE
LOWER 60S FAR WEST. NO BIG CHANGES THIS UPDATE.

UPDATE ISSUED AT 946 PM CDT MON SEP 2 2013

SURFACE HIGH PRESSURE OVER MINNESOTA WILL CONTINUE TO MOVE SOUTH
AND EAST TONIGHT AS LOW PRESSURE IN EASTERN MONTANA MOVES INTO THE
WESTERN DAKOTAS BY 12 UTC TUESDAY. INCREASING MID AND HIGH LEVEL
CLOUDINESS CONTINUES TO SPILL OVER THE WESTERN RIDGE INTO THE
DAKOTAS AND WILL INCREASE CLOUD COVER ACROSS THE WEST TONIGHT.
LATEST 01 UTC HRRR AND RAP INDICATE SHOWERS MOVING INTO THE FAR
WEST AROUND 12 UTC TUESDAY. WILL KEEP THE OVERNIGHT PERIOD DRY FOR
NOW BUT WILL INTRODUCE ISOLATED THUNDERSHOWERS INTO THE FAR
SOUTHWEST AT 12 UTC...A COUPLE HOURS EARLIER THAN THE PREVIOUS
FORECAST. OTHERWISE NO CHANGES TO THE GOING FORECAST. CURRENT
FORECAST LOW TEMPERATURES LOOK REASONABLE WITH TUESDAY MORNING
LOWS A GOOD 5-10 DEGREES WARMER THAN THIS MORNING.

UPDATE ISSUED AT 641 PM CDT MON SEP 2 2013

NO UPDATES THIS EVENING OTHER THAN POPULATING WITH THE LATEST
SENSIBLE WEATHER GRIDS AND INTERPOLATING THROUGH MID EVENING. HIGH
PRESSURE OVER THE EASTERN DAKOTAS WILL CONTINUE TO MOVE EAST AS
LOW PRESSURE DEVELOPS IN EASTERN MONTANA.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)

ISSUED AT 303 PM CDT MON SEP 2 2013

A RETURN TO WARM TEMPERATURES WILL HIGHLIGHT THE SHORT TERM
FORECAST.

THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON LEE SURFACE
TROUGHING ACROSS EASTERN MONTANA AND WYOMING DEEPENING THROUGH
TONIGHT...THEN FILLING ON TUESDAY AS STRONG SURFACE HIGH PRESSURE
PROPAGATES FROM CANADA INTO THE NORTHERN PLAINS LATE IN THE DAY
ON TUESDAY WITH A STRONG SURFACE COLD FRONT ON THE LEADING EDGE OF
THE HIGH PRESSURE MAKING IT INTO APPROXIMATELY THE US HIGHWAY 2
CORRIDOR BY LATE AFTERNOON. HIGHS ON TUESDAY ARE FORECAST TO CLIMB
INTO THE UPPER 80S AND LOWER 90S SOUTH OF THE AFOREMENTIONED COLD
FRONT. ISOLATED THUNDERSTORMS ARE POSSIBLE WEST OF HIGHWAY 83
TUESDAY AFTERNOON AS THE SHORTWAVE CURRENTLY ACROSS NORTHEAST UTAH
CRESTS THE RIDGE LATE TUESDAY AFTERNOON INTO WESTERN NORTH DAKOTA.
SHEAR AND INSTABILITY PROFILES ARE NOT SUPPORTIVE OF SEVERE
CONVECTION.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)

ISSUED AT 303 PM CDT MON SEP 2 2013

A BACKDOOR COLD FRONT MOVING THROUGH THE NORTHERN PLAINS TUESDAY
NIGHT WILL BRING COOLER TEMPERATURES TO WEST AND CENTRAL NORTH
DAKOTA ON WEDNESDAY...STILL ABOUT 5 DEGREES ABOVE NORMAL...WITH
HIGHS FROM THE MID 70S NORTH TO MID 80S SOUTH. THE WARMING TREND
THEN RESUMES THURSDAY INTO FRIDAY AS THE UPPER LEVEL RIDGE SHIFTS
EAST INTO THE GREAT PLAINS. STILL EXPECTING MOSTLY DRY CONDITIONS
OVER NORTH DAKOTA THROUGH THURSDAY NIGHT WITH A DRY NORTHWEST FLOW
ALOFT. MAY SEE A FEW SCATTERED SHOWERS/ISOLATED T-STORMS TUESDAY
EVENING AS AN EMBEDDED S/WV IMPULSE SLIDES EAST-SOUTHEAST THROUGH
THE DAKOTAS...AND AS THE COLD FRONT MOVES SOUTH ACROSS THE STATE.
WHILE INSTABILITY AND SHEAR PARAMETERS DO NOT INDICATE SEVERE
WEATHER...CANNOT COMPLETELY RULE OUT A STRONGER STORM OR TWO NEAR
THE COLD FRONT IN THE EVENING WHERE THE 12Z ECMWF INDICATES A
BRIEF PERIOD OF MODEST INSTABILITY NEAR 1500 J/KG.

AS WE HEAD INTO THE COMING WEEKEND...MODELS PROJECT THE RIDGE TO
BREAKDOWN AS A CLOSED UPPER LOW (NOW OFF THE PACIFIC NORTHWEST
U.S. COAST) MOVES INLAND THURSDAY...THEN EAST ACROSS THE
ROCKIES/TOWARDS THE NORTHERN PLAINS FRI NIGHT-SAT...AND EVENTUALLY
INTO THE REGION SUN-MON. AS THIS FEATURE APPROACHES...WILL START
TO SEE INCREASING CHANCES FOR PRECIPITATION WITH SLIGHT CHANCES
FRI/FRI NIGHT...AND BETTER CHANCES SATURDAY THROUGH MONDAY. THIS
FEATURE IS ALSO EXPECTED TO BRING COOLER WEATHER TO THE NORTHERN
PLAINS REGION...WHICH AT THIS TIME STILL LOOKS TO OCCUR POSSIBLY
SUNDAY WITH A BETTER CHANCE OF COOLER WEATHER NEXT SUNDAY NIGHT
INTO THE EARLY PORTIONS OF THE FOLLOWING WORK WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1230 AM CDT TUE SEP 3 2013

HIGH PRESSURE OVER IOWA AND LOW PRESSURE OVER MONTANA WILL RESULT IN
LIGHT EAST TO SOUTHEAST WINDS THROUGH 15Z AT TAF SITES.

AN UPPER LEVEL SHORTWAVE THAT WAS CURRENTLY OVER MONTANA/WYOMING IS
FORECAST TO ENTER WESTERN NORTH DAKOTA AFT 09Z AND MOVE SOUTHEAST
ACROSS NORTH DAKOTA TODAY. AS THIS OCCURS A SURFACE COLD FRONT THAT
WAS OVER MANITOBA AND SASKATCHEWAN IS FORECAST TO ENTER NORTH DAKOTA
AROUND 18Z AND MOVE SOUTHWARD ACROSS THE STATE AND EXIT NORTH DAKOTA
BY 06Z TUESDAY NIGHT/WEDNESDAY MORNING.

THESE FEATURES WILL PROVIDE A SLIGHT CHANCE OF THUNDERSTORMS ON
TUESDAY MAINLY WEST OF THE HIGHWAY 83 CORRIDOR. HOWEVER COVERAGE
WILL BE ISOLATED AND THUS WILL NOT MENTION A VCTS AT TAF SITES AT
THIS TIME. OTHERWISE VFR CONDITIONS AREA FORECAST. SOUTHERLY FLOW
ACROSS THE AREA WILL SHIFT NORTH AT KISN AND KMOT TUESDAY AFTERNOON
BEHIND THE COLD FRONT. SOUTHERN TAF SITES OF KDIK/KBIS/KJMS SHOULD
SEE A WIND SHIFT DURING THE EVENING HOURS AS THE FRONT MAKES ITS WAY
SOUTHWARD SLOWLY.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JV
SHORT TERM...AYD
LONG TERM...NH
AVIATION...JV







AREA FORECAST DISCUSSION

NWS MEMPHIS TN

 1144 PM CDT MON SEP 2 2013

.DISCUSSION...

UPDATED FOR 06Z AVIATION DISCUSSION

&&

.PREV DISCUSSION... /ISSUED 814 PM CDT MON SEP 2 2013/

UPDATE...

A COLD FRONT CURRENTLY STRETCHES FROM NEAR HUNTINGDON TENNESSEE TO
NEAR SEARCY ARKANSAS. SHOWER AND THUNDERSTORM ACTIVITY THAT WAS
OCCURRING ALONG AND AHEAD OF THE FRONT HAS DISSIPATED DUE TO THE
LOSS OF DAYTIME HEATING. HOWEVER...DON/T EXPECT THE RADAR SCOPE TO
STAY CLEAR OVERNIGHT. THE LATEST HRRR SHOWS ISOLATED SHRAS/TSRAS
POPPING UP OVERNIGHT SOUTH OF THE FRONT. THUS WILL CONTINUE WITH
SLIGHT CHANCE TO CHANCE POPS AT THIS TIME. MEANWHILE...DRIER AIR
WILL FILTER INTO NORTHERN LOCATIONS OF THE MIDSOUTH OVERNIGHT.
DEWPOINTS ARE IN THE UPPER 50S TO LOWER 60S JUST NORTHWEST OF THE
CWA. CURRENT FORECAST LOOKS GOOD...MAY SEND UPDATE WITH POPS
SHORTLY BEFORE MIDNIGHT REFLECTING CURRENT POSITION OF FRONT.

KRM

DISCUSSION... /ISSUED 243 PM CDT MON SEP 2 2013/

SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE MIDSOUTH AND
WILL LIKELY INTERRUPT MANY AFTERNOON LABOR DAY PLANS. HOWEVER...I
WOUND NOT CANCEL PLANS ALL TOGETHER...STORMS SHOULD NOT LAST MORE
THAN 30-45 MIN`S. SECURE ANY LAWN FURNITURE...SEEK SHELTER FROM
THE LIGHTNING AND RESUME THE FESTIVITIES AFTER STORMS PASS.

A COLD FRONT IS MOVING INTO THE MIDSOUTH. AT 2:00 PM IT WAS
LOCATED GENERALLY ALONG A LINE FROM PARIS TENNESSEE TO NEAR
INTERSTATE 40 IN EAST CENTRAL ARKANSAS. TO THE SOUTH OF THIS
BOUNDARY...SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY WITH A
DRIER COOLER AIRMASS WORKING INTO TO THE MIDSOUTH TO ITS NORTH AND
WEST. WINDS WILL SHIFT FROM THE NORTH BEHIND THE FRONT...BUT THE
DRIER AIR WILL TAKE SEVERAL MORE HOURS TO ARRIVE. CURRENTLY...DEW
POINTS ARE STILL IN THE LOW 70S ACROSS MOST OF NORTHEAST
ARKANSAS...BUT LOW 60S...EVEN UPPER 50S ARE NOT FAR AWAY IN
CENTRAL AND SOUTHWESTERN MISSOURI.

ONGOING CONVECTION MAINLY ACROSS WEST TENNESSEE...WILL CONTINUE TO
INCREASE IN COVERAGE...AS THEY MOVE TO THE EAST TO SOUTHEAST THIS
AFTERNOON AND TONIGHT. THEY ARE DEVELOPING IN A HIGH
INSTABILITY...LOW SHEAR ENVIRONMENT FEATURING CAPE`S APPROACHING
3000 AND LI`S IN THE -3 TO -6 RANGE. EFFECTIVE BULK SHEAR IS LESS
THAN 25 KTS. NEGATIVE 10C DEGREE LEVELS ARE CURRENTLY AROUND
20-21K FT WITH -20C AROUND 25K FT. THE LIKELIHOOD OF HAIL IS
FAIRLY LOW...BUT CERTAINLY CANNOT BE RULED OUT. THE MAIN THREAT
FROM ANY STRONG OR SEVERE STORMS WILL BE LOCALIZED DAMAGING WIND.
HOWEVER...EVEN THOUGH LIGHTNING IS NOT A SEVERE WEATHER
PARAMETER FOR WARNING PURPOSES...THAT IS TRULY THE MAIN THREAT
FROM THESE STORMS...ESPECIALLY CONSIDERING THE NUMBER OF OUTDOOR
ACTIVITIES ONGOING TODAY. KEEP AN EYE TO THE SKY. STORMS WILL
CONTINUE TONIGHT...BUT LIKELY BECOME CONFINED TO NORTH MISSISSIPPI
BY MIDNIGHT. FLOODING IS ALSO A CONCERN...RAINFALL RATES IN EXCESS
OF 2.5 INCHES PER HOUR AND TRAINING THUNDERSTORMS COULD RESULT IN
LOCALIZED FLOODING PROBLEMS. SEVERAL FLASH FLOOD WARNINGS HAVE
ALREADY BEEN ISSUED IN WEST TENNESSEE AND NORTH MISSISSIPPI.

TOMORROW...THAT COOLER DRIER AIRMASS WILL BE EVIDENT. NEAR NORMAL
TEMPERATURES...OR HIGHS GENERALLY IN THE MIDDLE TO UPPER 80S ARE
EXPECTED...BUT DEW POINTS WILL BE IN THE LOW TO MIDDLE 60S
INSTEAD OF THE LOW 70S RESULTING IN MUCH MORE PLEASANT CONDITIONS.
NO RAINFALL IS EXPECTED TOMORROW TROUGH THE END OF THE FORECAST
PERIOD. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE NORMAL AS A
RIDGE ALOFT DOMINATES OUR WEATHER PATTERN.

&&

.AVIATION...

06Z TAF CYCLE

MAIN CONCERN OVERNIGHT IS THE DEVELOPMENT OF FOG...ESPECIALLY IN
AREAS THAT HAD RAIN EARLIER. CLEARING SKIES...LIGHT WINDS AND
EARLIER RAIN HAVE ALREADY RESULTED IN LIFR VSBYS AT KMKL WHICH
COULD DETERIORATE TO VLIFR AT TIMES OVER THE NEXT FEW HOURS
DEPENDING ON WHETHER DRIER AIR FILTERS IN. DRIER AIR HAS WORKED
INTO KJBR SO VFR CONDS WILL PREVAIL THERE THROUGHOUT THE PERIOD.
EXPECT ENOUGH MIXING INVOF KMEM TO KEEP FOG DEVELOPMENT AT BAY.
KTUP DID NOT HAVE ANY RAIN SO ONLY SOME MVFR VSBYS IN LIGHT FOG
ARE POSSIBLE. VFR CONDS EXPECTED AREA WIDE ON TUESDAY. LIGHT
NORTH/CALM WINDS OVERNIGHT WILL BECOME NNE AT 7-10 KTS BY 03/15Z.

SJM

&&

.PRELIMINARY POINT TEMPS/POPS...
MEM  71  88  68  89 /  30   0  10  10
MKL  64  85  58  86 /  20   0  10  10
JBR  66  86  62  88 /  10   0  10  10
TUP  70  89  66  90 /  40  10  10  10

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

$$








AREA FORECAST DISCUSSION...UPDATED

NWS FORT WORTH TX

 1131 PM CDT MON SEP 2 2013

.AVIATION...
/6Z TAFS/

VFR CONDITIONS PREVAIL ACROSS NORTH TEXAS. AS MENTIONED IN THE
DISCUSSION BELOW...WEAK FRONTAL BOUNDARY REMAINS PLACED ACROSS THE
METROPLEX LATE THIS EVENING AND COULD SERVE AS A FOCUS FOR
ISOLATED CONVECTION DURING THE OVERNIGHT HOURS GIVEN THE FAIRLY
MOIST LOW LEVELS. FOR NOW...WILL LEAVE MENTION OF ANY
PRECIPITATION OUT BUT WILL HAVE TO MONITOR THE NEXT 6 HOURS FOR
POSSIBLE DEVELOPMENT. OTHERWISE...VFR CONDITIONS WILL PREVAIL WITH
LGT/VAR WINDS BECOMING EAST/NORTHEAST IN THE METROPLEX BY
MORNING. FARTHER SOUTH...A MORE EASTERLY DIRECTION CAN BE
EXPECTED.

DUNN

&&

.UPDATE...

RAN A LATE EVENING UPDATE TO INTRODUCE A 20 PERCENT CHANCE OF
STORMS IN THE FORECAST FOR LOCATIONS ALONG AND EAST OF A LINE FROM
DECATUR TO CLEBURNE FOR TONIGHT THROUGH SUNRISE TOMORROW.

THE PRIMARY REASON FOR THIS LATE EVENING UPDATE WAS BECAUSE OF A
FRONTAL BOUNDARY MOVING SOUTH TOWARDS THE INTERSTATE 30 CORRIDOR
AS OF 11 PM CDT. LATE AFTERNOON TO EARLY EVENING THUNDERSTORM
ACTIVITY MASKED THE MOVEMENT OF THIS BOUNDARY...BUT WITH ALL
THUNDERSTORM ACTIVITY DISSIPATED...IT IS EASY TO SEE IT MOVING
SOUTH AT THIS TIME. 04Z/11PM SURFACE OBSERVATIONS HAVE THE FRONT
LOCATED NEAR A LINE FROM DECATUR TO MCKINNEY TO COOPER. SURFACE
DEW POINTS OUT AHEAD OF THIS BOUNDARY WERE OBSERVED IN THE LOWER
TO MID 70S WHILE DEW POINTS TO THE NORTH WERE IN THE LOWER 60S.
WHILE THE TEMPERATURE DIFFERENCE ON EITHER SIDE OF THE BOUNDARY
WAS SMALL AS OF 11 PM...THE DIFFERENCE IN MOISTURE REPRESENTS A
NICE THETA-E GRADIENT TO TRACK IN HIGH RESOLUTION MODEL OUTPUT.

THE 03Z RAP SHOWS THIS THETA-E GRADIENT NICELY...AND INDICATES
THAT THE RIDGE OF THETA-E ALONG AND JUST SOUTH OF THE BOUNDARY
WILL SHIFT SOUTH OVER THE METROPLEX...CONTINUING EAST ALONG THE
I-20 AND I-30 CORRIDORS TO THE EASTERN BOUNDARY OF OUR CWA.
ANYWHERE FROM 08 TO 10Z /3 TO 5 AM/ THE RAP INDICATES THAT THIS
BOUNDARY WILL STALL LEAVING THE THETA-E RIDGE IN PLACE OVER THE
METROPLEX EXTENDING EAST ALONG THE I-20 CORRIDOR. THE HRRR
INDICATES THAT ONCE THIS BOUNDARY STALLS...IT MAY SERVE AS A FOCUS
FOR OVERNIGHT THUNDERSTORM INITIATION. RAW MODEL OUTPUT FROM THE
02Z HRRR SHOWS SCATTERED RAIN SHOWERS AND THUNDERSTORMS DEVELOPING
FROM THE DALLAS/TARRANT COUNTY BORDER EASTWARD DOWN THE INTERSTATE
20 CORRIDOR FROM 08 TO 10Z. GRANTED...NOT ALL MODEL OUTPUT
SUPPORTS THIS SOLUTION...BUT SINCE THE BOUNDARY IS EASY TO TRACK
NOW AND IT IS MOVING SOUTH WITH HIGH THETA-E AIR OUT AHEAD OF
IT...WENT AHEAD AND FOLLOWED THIS GUIDANCE FOR THE FORECAST
UPDATE.

NO SEVERE WEATHER IS EXPECTED IF STORMS DEVELOP LATE TONIGHT/EARLY
TOMORROW MORNING...HOWEVER ANY STORM MAY PRODUCE LOCALLY HEAVY
RAINFALL AND STRONG OUTFLOW WINDS UPON COLLAPSING. THERE IS STILL
VERY LITTLE DEEP LAYER SHEAR...SO SINGLE CELL/PULSE TYPE
THUNDERSTORMS WOULD BE THE DOMINANT STORM MODE IF ANYTHING MANAGES
TO DEVELOP. THE BOUNDARY LOOKS TO WASH OUT AFTER SUNRISE...SO ANY
LINGERING THUNDERSTORM ACTIVITY SHOULD FOLLOW SUIT.

CAVANAUGH

&&

.PREV DISCUSSION... /ISSUED 332 PM CDT MON SEP 2 2013/
A WEAK COLD FRONT WILL EASE THROUGH THE REGION TONIGHT THROUGH
TUESDAY AND BRING ONLY SLIGHTLY COOLER AND DRIER AIR. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AHEAD
OF THE COLD FRONT TONIGHT AND AFFECT MAINLY THE SOUTHERN ZONES.
ANY STORMS THAT DEVELOP TONIGHT WILL BE AIDED BY LARGE SCALE LIFT
FROM DIFFLUENT NORTHERLY FLOW ALOFT. A FEW STRONG TO SEVERE STORMS
ARE POSSIBLE WITH A THREAT OF DAMAGING DOWNBURST WINDS. A FEW
STORMS MAY LINGER IN THE EXTREME SOUTHERN ZONES ON TUESDAY ALONG
AND AHEAD OF THE WEAK COLD FRONT.

UPPER LEVEL HIGH PRESSURE WILL BUILD BACK OVER THE STATE THE
MIDDLE OF THE WEEK THROUGH THE WEEKEND AND RESULT IN A RETURN OF
HOT DAYS...WARM NIGHTS AND LITTLE CHANCE FOR RAIN. EXPECT
AFTERNOON HIGHS FROM THE MIDDLE 90S TO AROUND 100 EACH DAY WITH
OVERNIGHT LOWS GENERALLY IN THE 70S.

LOOKING BEYOND THIS FORECAST CYCLE...BOTH THE GFS AND ECMWF SHOW
THE UPPER RIDGE BREAKING DOWN BY THE MIDDLE OF NEXT WEEK WITH A
SUBSTANTIAL COLD FRONT MOVING THROUGH THE NORTHERN AND CENTRAL
PLAINS. THE SECOND TO THIRD WEEK OF SEPTEMBER IS TYPICALLY WHEN WE
SEE THE FIRST DECENT COLD FRONT...SO THESE SOLUTIONS MAY NOT BE
TOO FAR OFF.

79

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  73  98  74 100  77 /  20   5   5   5   5
WACO, TX              74  97  73  99  75 /  20  10  10  10  10
PARIS, TX             68  96  69  95  70 /  20   5   5   5   5
DENTON, TX            67  97  70  99  72 /  20   5   5   5   5
MCKINNEY, TX          67  96  68  98  70 /  20   5   5   5   5
DALLAS, TX            74  97  76 100  77 /  20   5   5   5   5
TERRELL, TX           71  97  72  97  74 /  20   5   5   5   5
CORSICANA, TX         73  96  73  98  74 /  20  10  10  10  10
TEMPLE, TX            72  98  72  99  74 /  30  20  10  10  10
MINERAL WELLS, TX     67  97  71  98  74 /  10   5   5   5   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$






AREA FORECAST DISCUSSION

NWS FORT WORTH TX

 1120 PM CDT MON SEP 2 2013

.UPDATE...

RAN A LATE EVENING UPDATE TO INTRODUCE A 20 PERCENT CHANCE OF
STORMS IN THE FORECAST FOR LOCATIONS ALONG AND EAST OF A LINE FROM
DECATUR TO CLEBURNE FOR TONIGHT THROUGH SUNRISE TOMORROW.

THE PRIMARY REASON FOR THIS LATE EVENING UPDATE WAS BECAUSE OF A
FRONTAL BOUNDARY MOVING SOUTH TOWARDS THE INTERSTATE 30 CORRIDOR
AS OF 11 PM CDT. LATE AFTERNOON TO EARLY EVENING THUNDERSTORM
ACTIVITY MASKED THE MOVEMENT OF THIS BOUNDARY...BUT WITH ALL
THUNDERSTORM ACTIVITY DISSIPATED...IT IS EASY TO SEE IT MOVING
SOUTH AT THIS TIME. 04Z/11PM SURFACE OBSERVATIONS HAVE THE FRONT
LOCATED NEAR A LINE FROM DECATUR TO MCKINNEY TO COOPER. SURFACE
DEW POINTS OUT AHEAD OF THIS BOUNDARY WERE OBSERVED IN THE LOWER
TO MID 70S WHILE DEW POINTS TO THE NORTH WERE IN THE LOWER 60S.
WHILE THE TEMPERATURE DIFFERENCE ON EITHER SIDE OF THE BOUNDARY
WAS SMALL AS OF 11 PM...THE DIFFERENCE IN MOISTURE REPRESENTS A
NICE THETA-E GRADIENT TO TRACK IN HIGH RESOLUTION MODEL OUTPUT.

THE 03Z RAP SHOWS THIS THETA-E GRADIENT NICELY...AND INDICATES
THAT THE RIDGE OF THETA-E ALONG AND JUST SOUTH OF THE BOUNDARY
WILL SHIFT SOUTH OVER THE METROPLEX...CONTINUING EAST ALONG THE
I-20 AND I-30 CORRIDORS TO THE EASTERN BOUNDARY OF OUR CWA.
ANYWHERE FROM 08 TO 10Z /3 TO 5 AM/ THE RAP INDICATES THAT THIS
BOUNDARY WILL STALL LEAVING THE THETA-E RIDGE IN PLACE OVER THE
METROPLEX EXTENDING EAST ALONG THE I-20 CORRIDOR. THE HRRR
INDICATES THAT ONCE THIS BOUNDARY STALLS...IT MAY SERVE AS A FOCUS
FOR OVERNIGHT THUNDERSTORM INITIATION. RAW MODEL OUTPUT FROM THE
02Z HRRR SHOWS SCATTERED RAIN SHOWERS AND THUNDERSTORMS DEVELOPING
FROM THE DALLAS/TARRANT COUNTY BORDER EASTWARD DOWN THE INTERSTATE
20 CORRIDOR FROM 08 TO 10Z. GRANTED...NOT ALL MODEL OUTPUT
SUPPORTS THIS SOLUTION...BUT SINCE THE BOUNDARY IS EASY TO TRACK
NOW AND IT IS MOVING SOUTH WITH HIGH THETA-E AIR OUT AHEAD OF
IT...WENT AHEAD AND FOLLOWED THIS GUIDANCE FOR THE FORECAST
UPDATE.

NO SEVERE WEATHER IS EXPECTED IF STORMS DEVELOP LATE TONIGHT/EARLY
TOMORROW MORNING...HOWEVER ANY STORM MAY PRODUCE LOCALLY HEAVY
RAINFALL AND STRONG OUTFLOW WINDS UPON COLLAPSING. THERE IS STILL
VERY LITTLE DEEP LAYER SHEAR...SO SINGLE CELL/PULSE TYPE
THUNDERSTORMS WOULD BE THE DOMINANT STORM MODE IF ANYTHING MANAGES
TO DEVELOP. THE BOUNDARY LOOKS TO WASH OUT AFTER SUNRISE...SO ANY
LINGERING THUNDERSTORM ACTIVITY SHOULD FOLLOW SUIT.

CAVANAUGH

&&

.AVIATION...
/00Z TAFS/

VFR CONDITIONS PREVAIL ACROSS MOST OF NORTH TEXAS OUTSIDE OF
SCATTERED THUNDERSTORMS. EARLY EVENING SATELLITE IMAGERY SHOWS AN
AREA OF CU SOUTH OF WACO AND ANOTHER AREA ALONG THE RED RIVER AND
NORTHEAST OF THE METROPLEX. THESE ARE WHERE SCATTERED
THUNDERSTORMS ARE ONGOING AND SHOULD CONTINUE FOR THE NEXT COUPLE
OF HOURS. THE MAJOR AIRPORTS APPEAR TO BE UNDER THE INFLUENCE OF
WEAK SUBSIDENCE AT THE MOMENT AND WITH LOSS OF DAYTIME HEATING
RAPIDLY APPROACHING...THINK WIDESPREAD ADDITIONAL DEVELOPMENT
APPEARS UNLIKELY. WILL MAINTAIN VFR CONDS THROUGH THE PERIOD WITH
WINDS BECOMING NORTHERLY OVER THE NEXT FEW HOURS. VFR CONDS
EXPECTED ON TUESDAY.

DUNN


&&



.PREV DISCUSSION... /ISSUED 332 PM CDT MON SEP 2 2013/
A WEAK COLD FRONT WILL EASE THROUGH THE REGION TONIGHT THROUGH
TUESDAY AND BRING ONLY SLIGHTLY COOLER AND DRIER AIR. ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP AHEAD
OF THE COLD FRONT TONIGHT AND AFFECT MAINLY THE SOUTHERN ZONES.
ANY STORMS THAT DEVELOP TONIGHT WILL BE AIDED BY LARGE SCALE LIFT
FROM DIFFLUENT NORTHERLY FLOW ALOFT. A FEW STRONG TO SEVERE STORMS
ARE POSSIBLE WITH A THREAT OF DAMAGING DOWNBURST WINDS. A FEW
STORMS MAY LINGER IN THE EXTREME SOUTHERN ZONES ON TUESDAY ALONG
AND AHEAD OF THE WEAK COLD FRONT.

UPPER LEVEL HIGH PRESSURE WILL BUILD BACK OVER THE STATE THE
MIDDLE OF THE WEEK THROUGH THE WEEKEND AND RESULT IN A RETURN OF
HOT DAYS...WARM NIGHTS AND LITTLE CHANCE FOR RAIN. EXPECT
AFTERNOON HIGHS FROM THE MIDDLE 90S TO AROUND 100 EACH DAY WITH
OVERNIGHT LOWS GENERALLY IN THE 70S.

LOOKING BEYOND THIS FORECAST CYCLE...BOTH THE GFS AND ECMWF SHOW
THE UPPER RIDGE BREAKING DOWN BY THE MIDDLE OF NEXT WEEK WITH A
SUBSTANTIAL COLD FRONT MOVING THROUGH THE NORTHERN AND CENTRAL
PLAINS. THE SECOND TO THIRD WEEK OF SEPTEMBER IS TYPICALLY WHEN WE
SEE THE FIRST DECENT COLD FRONT...SO THESE SOLUTIONS MAY NOT BE
TOO FAR OFF.

79



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  73  98  74 100  77 /  20   5   5   5   5
WACO, TX              74  97  73  99  75 /  20  10  10  10  10
PARIS, TX             68  96  69  95  70 /  20   5   5   5   5
DENTON, TX            67  97  70  99  72 /  20   5   5   5   5
MCKINNEY, TX          67  96  68  98  70 /  20   5   5   5   5
DALLAS, TX            74  97  76 100  77 /  20   5   5   5   5
TERRELL, TX           71  97  72  97  74 /  20   5   5   5   5
CORSICANA, TX         73  96  73  98  74 /  20  10  10  10  10
TEMPLE, TX            72  98  72  99  74 /  30  20  10  10  10
MINERAL WELLS, TX     67  97  71  98  74 /  10   5   5   5   5

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

 /






AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 325 AM CDT TUE SEP 3 2013

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 325 AM CDT TUE SEP 3 2013

SURFACE HIGH PRESSURE WAS CENTERED OVER THE FORECAST AREA RESULTING
IN CLEAR/CALM/COOL CONDITIONS. TEMPERATURES AT 3 AM RANGED FROM A
VERY CHILLY 38 DEGREES AT BLACK RIVER FALLS AND VOLK FIELD WI...TO
THE 40-50 DEGREE RANGE ELSEWHERE. FOG WAS ALSO NOTED ACROSS THE CRANBERRY
COUNTRY OF CENTRAL WI WITH VISIBILITIES LOCALLY BELOW A MILE.
LOOKING OUT THE OFFICE...FOG/STRATUS WAS ALSO FORMING DOWN IN THE
MISSISSIPPI RIVER CHANNEL. IMMEDIATE CONCERN WILL BE THE EXTENT OF
FOG THIS MORNING UNDER THE RIDGE OF HIGH PRESSURE. WILL MONITOR HERE
OVER THE NEXT HOUR TO SEE IF ANY HEADLINES WILL BE NEEDED. ONCE THE
FOG LIFTS THIS MORNING...LOOKING FOR A SUNNY DAY WITH TEMPERATURES
RIGHT AROUND NORMAL IN THE MIDDLE AND UPPER 70S.

HIGH PRESSURE WILL SLIP SOUTH AND EAST OF THE AREA TONIGHT AS A COLD
FRONT PUSHES SOUTHWARD OUT OF CANADA TO NEAR THE I-90 CORRIDOR BY
SUNRISE. NOT MUCH EXPECTED OUT OF THIS FRONT OTHER THAN SOME
INCREASE IN SOME MID/HIGH CLOUDS. OTHERWISE...LOOK FOR LOWS IN THE
50S...EXCEPT FOR A FEW UPPER 40 READINGS ACROSS THE CRANBERRY BOG
COUNTRY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 325 AM CDT TUE SEP 3 2013

LOOK FOR THE COLD FRONT TO SLIP SOUTH OF THE AREA ON WEDNESDAY. THE
NAM TRIES TO DEVELOP CONVECTION JUST WEST OF THE AREA DURING THE
AFTERNOON IN RESPONSE TO WEAK ISENTROPIC UPGLIDE IN THE 850-700MB
LAYER OVER THIS FRONTAL BOUNDARY. THE NAM IS THE ONLY MODEL DOING
THIS BUT WARRANTS KEEPING AN EYE ON. WILL LEAVE FORECAST DRY FOR NOW
WITH AT LEAST LIKELY SEE SOME INCREASE IN SOME MID-CLOUD MAINLY
SOUTH OF I-94. OTHERWISE...PLAN ON HIGHS IN THE MID/UPPER 70S ACROSS
NORTH CENTRAL WI...AND LOWER TO MIDDLE 80S ELSEWHERE.

FOR WEDNESDAY NIGHT THROUGH FRIDAY...HIGH PRESSURE WILL REMAIN IN
CONTROL ACROSS THE REGION WITH WARMING TEMPERATURES. LOOK FOR HIGHS
IN THE MIDDLE 70S TO LOWER 80S ON THURSDAY...WARMING INTO THE LOWER
AND MIDDLE 80S ON FRIDAY.

GFS AND ECMWF SHOW A COLD FRONT SLIPPING SOUTHEAST INTO THE
REGION SATURDAY WITH BEST MOISTURE CONVERGENCE/SHOWER AND
THUNDERSTORM CHANCES STAYING MAINLY ACROSS EASTERN WI. A FAIRLY
STRONG CAP LOOKS TO REMAIN IN PLACE OVER US...KEEPING US VERY WARM
AND DRY. DID INCLUDE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
OVER THE FAR EASTERN PORTION OF THE FORECAST AREA...ON THE EASTERN
PERIPHERY OF THE STRONGER CAPPING. PLAN ON HIGHS SATURDAY IN THE
MIDDLE AND UPPER 80S.

SHOWER AND THUNDERSTORM CHANCES OVERSPREAD THE AREA SATURDAY NIGHT
THROUGH MONDAY AS THE FRONTAL BOUNDARY STALLS ACROSS THE REGION AND
LOW PRESSURE APPROACHES FROM THE PLAINS. HIGHS ON SUNDAY AND MONDAY
ARE EXPECTED TO BE IN THE MIDDLE 70S TO THE LOWER 80S.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT
1140 PM CDT MON SEP 2 2013

NO REAL CHANGES HAVE BEEN PRESENTED BY THE 03.00Z NAM OR 03.03Z
RAP. THE SURFACE HIGH WILL CONTINUE TO DRIFT EAST AND BE OVER THE
AREA FOR THE REMAINDER OF THE NIGHT. SKIES HAVE CLEARED OUT AND
WINDS HAVE BECOME LIGHT UP THROUGH AT LEAST 5 THOUSAND FEET. THE
TEMP/DEW POINT SPREAD AT KLSE WAS DOWN TO 4 DEGREES AT 03Z AND 3
DEGREES AT 04Z...SO THINGS STILL APPEAR TO BE ON TRACK FOR A
VALLEY FOG EVENT WITH DENSE FOG FOR KLSE. THE RAP STILL DOES NOT
WANT TO SATURATE AT KLSE TONIGHT...WHICH STILL LENDS A LITTLE BIT
OF DOUBT TO WHETHER THE FOG WILL FORM OR NOT. THE NAM IS ALSO NOW
SUGGESTING THAT FOG TO FORM AT KRST AS WELL. BUT BASED ON
PERSISTENCE OF WHAT HAPPENED LAST NIGHT WHERE THE FOG ONLY FORMED
UNDER THE HIGH WHERE IT HAD RECENTLY RAINED...WILL NOT INCLUDE ANY
FOG FOR NOW. ONCE THE FOG BURNS OFF...VFR CONDITIONS FOR THE REST
OF THE PERIOD AS THE HIGH SLIDES OFF TO THE EAST.

&&

.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

 1140 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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1140 PM CDT MON SEP 2 2013

NO REAL CHANGES HAVE BEEN PRESENTED BY THE 03.00Z NAM OR 03.03Z
RAP. THE SURFACE HIGH WILL CONTINUE TO DRIFT EAST AND BE OVER THE
AREA FOR THE REMAINDER OF THE NIGHT. SKIES HAVE CLEARED OUT AND
WINDS HAVE BECOME LIGHT UP THROUGH AT LEAST 5 THOUSAND FEET. THE
TEMP/DEW POINT SPREAD AT KLSE WAS DOWN TO 4 DEGREES AT 03Z AND 3
DEGREES AT 04Z...SO THINGS STILL APPEAR TO BE ON TRACK FOR A
VALLEY FOG EVENT WITH DENSE FOG FOR KLSE. THE RAP STILL DOES NOT
WANT TO SATURATE AT KLSE TONIGHT...WHICH STILL LENDS A LITTLE BIT
OF DOUBT TO WHETHER THE FOG WILL FORM OR NOT. THE NAM IS ALSO NOW
SUGGESTING THAT FOG TO FORM AT KRST AS WELL. BUT BASED ON
PERSISTENCE OF WHAT HAPPENED LAST NIGHT WHERE THE FOG ONLY FORMED
UNDER THE HIGH WHERE IT HAD RECENTLY RAINED...WILL NOT INCLUDE ANY
FOG FOR NOW. ONCE THE FOG BURNS OFF...VFR CONDITIONS FOR THE REST
OF THE PERIOD AS THE HIGH SLIDES OFF TO THE EAST.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04








AREA FORECAST DISCUSSION...UPDATED

NWS PEACHTREE CITY GA

 953 AM EDT TUE SEP 3 2013

.UPDATE...
WEAK COLD FRONT MOVING INTO N GA. BEST CHANCES FOR SHOWERS AND
STORMS APPEAR TO BE S OF FRONT ACROSS CENTRAL AND PORTIONS OF N
GA THIS AFTERNOON WHERE BEST INSTABILITY IS FORECAST. BDL


&&

.PREV DISCUSSION... /ISSUED 729 AM EDT TUE SEP 3 2013/

SHORT TERM /TODAY THROUGH WEDNESDAY/...
DEEP UPPER TROUGH IN PLACE OVER THE EASTERN HALF OF THE COUNTRY...
WITH THE TROUGH AXIS PARALLEL TO THE SOUTHERN APPALACHIANS AT THE
START OF THE SHORT TERM. ASSOCIATED SURFACE FRONT CURRENTLY LOCATED
FROM NEAR THE UPPER OHIO VALLEY...STRETCHING THROUGH THE MID-SOUTH
AND TO NEAR THE RED RIVER AT AFD TIME. THE FRONT WILL WORK ITS WAY
SOUTHEAST THROUGH THE DAY...WITH DRIER AIR BEGINNING TO FILTER INTO
THE STATE FOR TONIGHT. SHORT-TERM GUIDANCE IS IN PRETTY GOOD
AGREEMENT WITH THE MASS FIELDS. NOT A LOT OF SYNOPTIC LIFT TO SPEAK
OF TODAY AS THE FRONT CONTINUES TO OCCLUDE...BUT THERE SHOULD BE AT
LEAST SOME SYNOPTIC CONTRIBUTION IN THE FORM OF WEAK DIVERGENCE
ALOFT /RIGHT ENTRANCE REGION OF THE BARELY-THERE UPPER JET/ AND OF
COURSE DPVA AHEAD OF THE SHORTWAVE ITSELF...BOTH OF THESE MAXIMIZED
ACROSS CENTRAL GEORGIA FOR THIS AFTERNOON.

OF IMMEDIATE CONCERN IS THE EVOLUTION OF CONVECTION THROUGH THE
EARLY MORNING HOURS. PRE-FRONTAL CONVECTION HAS FIRED ACROSS
NORTHWEST GEORGIA AT AFD TIME...AND IN SIMILAR MANNER TO YESTERDAY
MORNING THE CONVECTION FIRED ALONG AN INSTABILITY GRADIENT IN AN
AREA WHERE CIN IS MINIMIZED. LATEST RUNS OF THE HRRR ARE ACTUALLY
PICKING UP ON THIS AND PUSHING A CONVECTIVE COMPLEX ACROSS NORTH
GEORGIA BETWEEN NOW AND APPROXIMATELY 13Z. BASED ON WHAT HAPPENED
LAST NIGHT...THIS IS NOT AT ALL AN UNREASONABLE SOLUTION...AND OTHER
HIRES GUIDANCE POINTING TO THE SAME THING. ARW MEMBERS NOT QUITE SO
PRONOUNCED AS THE NMM THOUGH. HRRR HAS NOT BEEN DOING WELL THE PAST
FEW DAYS BUT PERHAPS IT HAS FINALLY CAUGHT UP...AND IN ANY CASE THE
OVERALL PATTERN IS SUPPORTIVE OF DEVELOPMENT OF THESE OVERNIGHT
CONVECTIVE COMPLEXES. AS WAS THE CASE YESTERDAY...WHATEVER DOES
DEVELOP ACROSS NORTH GEORGIA EARLY THIS MORNING WILL LIKELY
DISSIPATE BY MID-MORNING /AFTER SUNRISE/ AS MIXING INCREASES.
HOWEVER...IF SUCH A CONVECTIVE COMPLEX DEVELOPS /AS IT DID
YESTERDAY/...IT WILL LIKELY WREAK HAVOC ON HIGH TEMPS TODAY /AS IT
DID YESTERDAY/. AT THIS POINT IT IS NEARLY IMPOSSIBLE TO TRY TO PIN
DOWN THOSE DETAILS BUT SUFFICE IT TO SAY THAT WE COULD SEE SOME BIG
BUSTS AGAIN TODAY /AS WE DID YESTERDAY/.

CAPES INCREASE TO BETWEEN 1500-2000 J/KG THIS AFTERNOON AHEAD OF THE
FRONT...MAINLY FROM APPROXIMATELY THE ATLANTA METRO AREA AND POINT
SOUTH. EXPECT CONVECTION TO FIRE AGAIN THIS AFTERNOON WITH BEST
COVERAGE ACROSS CENTRAL GEORGIA BUT ISOLATED TO SCATTERED CONVECTION
POSSIBLE UP INTO THE METRO AREA. EXPECT THE BULK IF NOT ALL OF THE
ACTIVITY TO DIE DOWN BY 06Z AND THUS HAVE NO POPS ACROSS THE AREA
OVERNIGHT. THE FRONT WILL CONTINUE TO SAG SOUTH AND WE SHOULD SEE A
NOTICEABLE DIFFERENCE IN LOW TEMPS BETWEEN WHAT WE HAVE THIS MORNING
AND TONIGHT...GENERALLY DOWN 3-5 DEGREES.

FRONT SHOULD STALL SOMEWHERE ACROSS THE AREA ON WEDNESDAY...KEEPING
THE CHANCE FOR CONVECTION ACROSS CENTRAL GEORGIA MAINLY DURING THE
AFTERNOON. INFLUENCE OF DRIER AIR WILL BE FELT ACROSS NORTH GEORGIA
BUT NO REAL CAA ALOFT TO SPEAK OF SO DO NOT THINK THAT TEMPS
WEDNESDAY WILL BE MUCH IF AT ALL COOLER THAN THOSE TODAY. /AND
ACTUALLY IF WE HAVE RAIN-COOLED AIR FROM CONVECTION THIS MORNING
MESSING WITH TEMPS TODAY...THEN WEDNESDAY COULD ACTUALLY BE WARMER./
ALL THAT SAID...WENT WITH A GENERAL BIAS-ADJUSTED BLEND.

TDP

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

MODELS CONSISTENT IN KEEPING DRY AIR ACROSS NORTH GEORGIA THROUGH
THE END OF THE WEEK AS THE FRONTAL BOUNDARY STALLS JUST SOUTH OF
THE CWA. DRYING ALOFT AND LOW PRECIPITABLE WATER SHOULD KEEP
CONVECTION OUT OF MUCH OF THE CWA THROUGH THURSDAY NIGHT...EXCEPT
FOR SLIGHT CHANCE AFTERNOON AND EVENING ALONG THE LAST ROW OR TWO
OF COUNTIES SOUTH OF COLUMBUS TO MACON. MOISTURE BEGINS SPREADING
BACK INTO THE FORECAST AREA ON FRIDAY AS LOW LEVEL WINDS TURN TO
THE EAST AND SOUTHEAST. HOWEVER WITH UPPER RIDGE BUILDING OVER THE
SOUTHEAST STATES THROUGH THE END OF THE PERIOD...EXPECTING ONLY
LOW CHANCE OR SLIGHT CHANCE AFTERNOON AND EVENING THUNDERSTORMS
ACROSS THE AREA.

41

AVIATION...
12Z UPDATE...
MAINLY VFR THIS MORNING...WITH POCKETS OF MVFR FOG AROUND. TEMPO
IFR CIG CONDITIONS DID NOT MATERIALIZE...BUT METRO TAFS DID SEE
BRIEF THUNDER AROUND 10Z. BEST CHANCE THUNDER TODAY REMAINS AT
CSG/MCN WHERE HAVE INCLUDED TEMPO 18-22Z. OTHER TAFS JUST WENT
VCSH. IMPROVING CONDITIONS AFTER 00Z AND VFR THROUGH THE REST OF
THE PERIOD FOR NOW...THOUGH THERE ARE SOME HINTS AT BRIEF MVFR FOG
WEDNESDAY MORNING.. W TO NW WINDS...5-10KT DURING THE DAY AND LESS
THAN 5KT AT NIGHT.

//ATL CONFIDENCE...12Z UPDATE...
LOW ON POTENTIAL FOR BRIEF MVFR/IFR CIGS THIS MORNING.
MEDIUM ON CONVECTION THIS AFTERNOON.
HIGH ON ALL OTHER ELEMENTS.

TDP

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  68  89  66 /  40  20  10   5
ATLANTA         88  70  89  67 /  30  10   5   5
BLAIRSVILLE     84  61  84  61 /  50  10   5   5
CARTERSVILLE    89  65  88  64 /  20  10   5   5
COLUMBUS        91  72  91  69 /  30  20  20  10
GAINESVILLE     87  68  87  67 /  60  10  10   5
MACON           91  69  92  68 /  30  20  20  10
ROME            88  65  89  63 /  20   5   5   5
PEACHTREE CITY  89  66  88  63 /  30  20   5   5
VIDALIA         90  72  91  71 /  40  20  20  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BDL
LONG TERM....17
AVIATION...BDL






AREA FORECAST DISCUSSION...UPDATED

NWS PEACHTREE CITY GA

 729 AM EDT TUE SEP 3 2013

.PREV DISCUSSION... /ISSUED 357 AM EDT TUE SEP 3 2013/

SHORT TERM /TODAY THROUGH WEDNESDAY/...
DEEP UPPER TROUGH IN PLACE OVER THE EASTERN HALF OF THE COUNTRY...
WITH THE TROUGH AXIS PARALLEL TO THE SOUTHERN APPALACHIANS AT THE
START OF THE SHORT TERM. ASSOCIATED SURFACE FRONT CURRENTLY LOCATED
FROM NEAR THE UPPER OHIO VALLEY...STRETCHING THROUGH THE MID-SOUTH
AND TO NEAR THE RED RIVER AT AFD TIME. THE FRONT WILL WORK ITS WAY
SOUTHEAST THROUGH THE DAY...WITH DRIER AIR BEGINNING TO FILTER INTO
THE STATE FOR TONIGHT. SHORT-TERM GUIDANCE IS IN PRETTY GOOD
AGREEMENT WITH THE MASS FIELDS. NOT A LOT OF SYNOPTIC LIFT TO SPEAK
OF TODAY AS THE FRONT CONTINUES TO OCCLUDE...BUT THERE SHOULD BE AT
LEAST SOME SYNOPTIC CONTRIBUTION IN THE FORM OF WEAK DIVERGENCE
ALOFT /RIGHT ENTRANCE REGION OF THE BARELY-THERE UPPER JET/ AND OF
COURSE DPVA AHEAD OF THE SHORTWAVE ITSELF...BOTH OF THESE MAXIMIZED
ACROSS CENTRAL GEORGIA FOR THIS AFTERNOON.

OF IMMEDIATE CONCERN IS THE EVOLUTION OF CONVECTION THROUGH THE
EARLY MORNING HOURS. PRE-FRONTAL CONVECTION HAS FIRED ACROSS
NORTHWEST GEORGIA AT AFD TIME...AND IN SIMILAR MANNER TO YESTERDAY
MORNING THE CONVECTION FIRED ALONG AN INSTABILITY GRADIENT IN AN
AREA WHERE CIN IS MINIMIZED. LATEST RUNS OF THE HRRR ARE ACTUALLY
PICKING UP ON THIS AND PUSHING A CONVECTIVE COMPLEX ACROSS NORTH
GEORGIA BETWEEN NOW AND APPROXIMATELY 13Z. BASED ON WHAT HAPPENED
LAST NIGHT...THIS IS NOT AT ALL AN UNREASONABLE SOLUTION...AND OTHER
HIRES GUIDANCE POINTING TO THE SAME THING. ARW MEMBERS NOT QUITE SO
PRONOUNCED AS THE NMM THOUGH. HRRR HAS NOT BEEN DOING WELL THE PAST
FEW DAYS BUT PERHAPS IT HAS FINALLY CAUGHT UP...AND IN ANY CASE THE
OVERALL PATTERN IS SUPPORTIVE OF DEVELOPMENT OF THESE OVERNIGHT
CONVECTIVE COMPLEXES. AS WAS THE CASE YESTERDAY...WHATEVER DOES
DEVELOP ACROSS NORTH GEORGIA EARLY THIS MORNING WILL LIKELY
DISSIPATE BY MID-MORNING /AFTER SUNRISE/ AS MIXING INCREASES.
HOWEVER...IF SUCH A CONVECTIVE COMPLEX DEVELOPS /AS IT DID
YESTERDAY/...IT WILL LIKELY WREAK HAVOC ON HIGH TEMPS TODAY /AS IT
DID YESTERDAY/. AT THIS POINT IT IS NEARLY IMPOSSIBLE TO TRY TO PIN
DOWN THOSE DETAILS BUT SUFFICE IT TO SAY THAT WE COULD SEE SOME BIG
BUSTS AGAIN TODAY /AS WE DID YESTERDAY/.

CAPES INCREASE TO BETWEEN 1500-2000 J/KG THIS AFTERNOON AHEAD OF THE
FRONT...MAINLY FROM APPROXIMATELY THE ATLANTA METRO AREA AND POINT
SOUTH. EXPECT CONVECTION TO FIRE AGAIN THIS AFTERNOON WITH BEST
COVERAGE ACROSS CENTRAL GEORGIA BUT ISOLATED TO SCATTERED CONVECTION
POSSIBLE UP INTO THE METRO AREA. EXPECT THE BULK IF NOT ALL OF THE
ACTIVITY TO DIE DOWN BY 06Z AND THUS HAVE NO POPS ACROSS THE AREA
OVERNIGHT. THE FRONT WILL CONTINUE TO SAG SOUTH AND WE SHOULD SEE A
NOTICEABLE DIFFERENCE IN LOW TEMPS BETWEEN WHAT WE HAVE THIS MORNING
AND TONIGHT...GENERALLY DOWN 3-5 DEGREES.

FRONT SHOULD STALL SOMEWHERE ACROSS THE AREA ON WEDNESDAY...KEEPING
THE CHANCE FOR CONVECTION ACROSS CENTRAL GEORGIA MAINLY DURING THE
AFTERNOON. INFLUENCE OF DRIER AIR WILL BE FELT ACROSS NORTH GEORGIA
BUT NO REAL CAA ALOFT TO SPEAK OF SO DO NOT THINK THAT TEMPS
WEDNESDAY WILL BE MUCH IF AT ALL COOLER THAN THOSE TODAY. /AND
ACTUALLY IF WE HAVE RAIN-COOLED AIR FROM CONVECTION THIS MORNING
MESSING WITH TEMPS TODAY...THEN WEDNESDAY COULD ACTUALLY BE WARMER./
ALL THAT SAID...WENT WITH A GENERAL BIAS-ADJUSTED BLEND.

TDP

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

MODELS CONSISTENT IN KEEPING DRY AIR ACROSS NORTH GEORGIA THROUGH
THE END OF THE WEEK AS THE FRONTAL BOUNDARY STALLS JUST SOUTH OF
THE CWA. DRYING ALOFT AND LOW PRECIPITABLE WATER SHOULD KEEP
CONVECTION OUT OF MUCH OF THE CWA THROUGH THURSDAY NIGHT...EXCEPT
FOR SLIGHT CHANCE AFTERNOON AND EVENING ALONG THE LAST ROW OR TWO
OF COUNTIES SOUTH OF COLUMBUS TO MACON. MOISTURE BEGINS SPREADING
BACK INTO THE FORECAST AREA ON FRIDAY AS LOW LEVEL WINDS TURN TO
THE EAST AND SOUTHEAST. HOWEVER WITH UPPER RIDGE BUILDING OVER THE
SOUTHEAST STATES THROUGH THE END OF THE PERIOD...EXPECTING ONLY
LOW CHANCE OR SLIGHT CHANCE AFTERNOON AND EVENING THUNDERSTORMS
ACROSS THE AREA.

41

&&

.AVIATION...
12Z UPDATE...
MAINLY VFR THIS MORNING...WITH POCKETS OF MVFR FOG AROUND. TEMPO
IFR CIG CONDITIONS DID NOT MATERIALIZE...BUT METRO TAFS DID SEE
BRIEF THUNDER AROUND 10Z. BEST CHANCE THUNDER TODAY REMAINS AT
CSG/MCN WHERE HAVE INCLUDED TEMPO 18-22Z. OTHER TAFS JUST WENT
VCSH. IMPROVING CONDITIONS AFTER 00Z AND VFR THROUGH THE REST OF
THE PERIOD FOR NOW...THOUGH THERE ARE SOME HINTS AT BRIEF MVFR FOG
WEDNESDAY MORNING.. W TO NW WINDS...5-10KT DURING THE DAY AND LESS
THAN 5KT AT NIGHT.

//ATL CONFIDENCE...12Z UPDATE...
LOW ON POTENTIAL FOR BRIEF MVFR/IFR CIGS THIS MORNING.
MEDIUM ON CONVECTION THIS AFTERNOON.
HIGH ON ALL OTHER ELEMENTS.

TDP

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  68  89  66 /  40  20  10   5
ATLANTA         88  70  89  67 /  30  10   5   5
BLAIRSVILLE     84  61  84  61 /  50  10   5   5
CARTERSVILLE    89  65  88  64 /  20  10   5   5
COLUMBUS        91  72  91  69 /  30  20  20  10
GAINESVILLE     87  68  87  67 /  60  10  10   5
MACON           91  69  92  68 /  30  20  20  10
ROME            88  65  89  63 /  20   5   5   5
PEACHTREE CITY  89  66  88  63 /  30  20   5   5
VIDALIA         90  72  91  71 /  40  20  20  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$





AREA FORECAST DISCUSSION

NWS GRAY ME

 1005 AM EDT TUE SEP 3 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST TODAY...
PROVIDING THE FOCUS FOR THUNDERSTORMS THIS AFTERNOON. THE FRONT
WILL SWEEP OUT ALL THE WET AND HUMID WEATHER BY TONIGHT. A SECOND
COLD FRONT COMES THROUGH WEDNESDAY NIGHT...PROVIDING A BRIEF SHOT
OF MUCH COOLER AIR FOR THE END OF THE WEEK. HIGH PRESSURE WILL
BUILD ACROSS THE REGION LATE THURSDAY THROUGH SATURDAY. ANOTHER
COLD FRONT WILL CROSS NEW ENGLAND SATURDAY NIGHT AND SUNDAY
FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR MONDAY.

&&

.NEAR TERM /TODAY/...
10AM UPDATE...
HAVE UPDATED THE FORECAST TO ADJUST POP AND SKY FORECAST. LOW
CLOUDS OVER MAINE ARE ERODING AND SHIFTING TO THE EAST... ALLOWING
FOR A CLEAR SLOT TO FORM OVER MUCH OF NEW HAMPSHIRE AND NOW INTO
WESTERN MAINE. EXPECT THIS TREND TO CONTINUE WITH MUCH OF THE AREA
BREAKING OUT OF THE CLOUDS OVER THE NEXT FEW HOURS. COLD FRONT IS
PUSHING INTO WESTERN NEW HAMPSHIRE AT THIS TIME... AND WILL BE
LOCATED NEAR THE MAINE BORDER BY EARLY AFTERNOON. THIS SHOULD
PROVIDE THE FOCUS FOR THUNDERSTORMS TODAY. STILL UNCERTAIN HOW
WIDESPREAD STORMS WILL BE... BUT TIMING SHOULD BE AROUND OR
SHORTLY AFTER NOON... SHIFTING EAST THROUGH THE AFTERNOON.
FORECAST SOUNDINGS SHOW CAPE VALUES OF 1000 TO 1500 ACROSS WESTERN
MAINE AHEAD OF THE FRONT THIS AFTERNOON. THIS WILL COMBINE WITH
30 TO 40 KTS OF SHEAR TO CREATE THE POSSIBILITY OF STRONG OR
SEVERE THUNDERSTORMS INCLUDING SUPERCELLS. THE GREATEST THREAT
WILL BE FROM DAMAGING WINDS BUT LARGE HAIL IS ALSO POSSIBLE.

7AM UPDATE...
HAVE UPDATED THE GRIDS TO ADD AREAS OF DRIZZLE ACROSS THE REGION
PER LATEST SURFACE OBSERVATIONS. THIS DRIZZLE AND AREAS OF FOG
WILL SLOWLY BE LIFTING AND MIXING OUT THIS MORNING. STILL EXPECT
SHOWERS AND THUNDERSTORMS TO ERUPT DURING THE MIDDAY PERIOD. A FEW
SHOWERS ASSOCIATED WITH THE FRONT ALREADY IN EASTERN NEW YORK
STATE EARLY THIS MORNING.

REST OF THE FORECAST PACKAGE WILL REMAIN RELATIVELY UNCHANGED.

ORIGINAL DISCUSSION...
LOW CLOUDS AND FOG WILL SLOWLY MIX OUT ACROSS THE REGION THIS
MORNING. EASTERN AREAS...ESPECIALLY NEAR THE COASTLINE...WILL BE
SLOW TO IMPROVE. IN THE MEANTIME...THE LATEST HRRR MODEL RUN
CONTINUES TO SHOW SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING OVER
EASTERN NEW HAMPSHIRE AROUND 17Z. THIS PRECIPITATION IS IN
ASSOCIATION WITH AN APPROACHING COLD FRONT. WITH APPROACHING UPPER
LEVEL TROUGH...WIND MAX AND MODEST INSTABILITY...EXPECT A FEW
STORMS TO CONTAIN DAMAGING WINDS OR HAIL.

HAVE THEREFORE ADDED ENHANCED WORDING TO THE FORECAST PACKAGE.
THUNDERSTORMS WILL CONTINUE UNTIL THIS EVENING...HOWEVER SOME OF
THE CONVECTIVE ACTIVITY WILL HAVE A CHALLENGING TIME MAKING IT
THROUGH ANY REMAINING LOW CLOUDS AND FOG ALONG THE MIDCOAST.

LOOK FOR 70S IN MOST AREAS...HOWEVER SOUTHERN NEW HAMPSHIRE MAY
TIP THE 80 DEGREE MARK.

&&

.SHORT TERM /TONIGHT AND WEDNESDAY/...
THE PRECIPITATION EXITS THE REGION THIS EVENING AS THE COLD FRONT
MOVES EAST. DRIER AIR WILL FILTER INTO THE FORECAST AREA FROM THE
WEST. HOWEVER...PLENTY OF LOW LEVEL MOISTURE FROM RECENT HEAVY
RAINS WILL ALLOW FOR MORE PATCHY FOG TO DEVELOP.

BY WEDNESDAY...THE UPPER LEVEL TROUGH WILL PUSH EAST OF THE
REGION...AND WE WILL BE IN BETWEEN SYSTEMS. A STRONG COLD FRONT
WILL APPROACH FROM THE WEST...BUT MUCH OF THE CLOUDINESS AND ANY
PRECIPITATION WILL HOLD OFF UNTIL AFTER DARK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN THROUGH THE
FORECAST PERIOD. THE UPPER TROUGH LINGERS ACROSS THE REGION
THROUGH THE UPCOMING WEEKEND BEFORE THE UPSTREAM RIDGE ACROSS THE
INTER-MOUNTAIN WEST FINALLY WEAKENS...AND THE FLOW BECOMES MORE
ZONAL ACROSS THE FORECAST AREA. WE BEGIN THE PERIOD WITH A
RELATIVELY DEEP TROUGH ACROSS THE AREA...AND A SURFACE COLD FRONT
MAKING ITS WAY SOUTHWARD ACROSS THE REGION WEDNESDAY NIGHT AND
EARLY THURSDAY. THIS FRONT WILL USHER BELOW NORMAL TEMPERATURES
INTO THE AREA FOR THURSDAY AND FRIDAY AS HIGH PRESSURE BUILDS
SOUTH AND EAST FROM THE GREAT LAKES. A RETURN FLOW AROUND THE
HIGH WILL INTRODUCE MILDER AIR INTO THE REGION SATURDAY. ANOTHER
SHORTWAVE WILL DRIVE A STRONG COLD FRONT ACROSS THE AREA SATURDAY
NIGHT AND SUNDAY WITH HIGH PRESSURE AND DRY AIR TO FOLLOW FOR
MONDAY.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...AREAS OF LOW CLOUDINESS AND FOG WILL SLOWLY MIX OUT
OVER THE REGION THIS MORNING...WITH THE LAST AREA TO CLEAR BEING EASTERN
AREAS THIS MORNING...ESPECIALLY NEAR THE COASTLINE. HOWEVER...THE
IMPROVEMENT WILL BE BRIEF WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AFTER NOON TODAY FROM WEST TO EAST. THE LOCALLY STRONG
SHOWERS AND STORMS WILL END THIS EVENING...FOLLOWED BY MORE IFR
AND ISOLATED LIFR CONDITIONS IN DEVELOPING FOG. VFR CONDITIONS ON
WEDNESDAY.

LONG TERM...

WEDNESDAY NIGHT - THURSDAY...SCATTERED MVFR IN SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
SHORT TERM...A COLD FRONT WILL CROSS THE WATERS TODAY WITH
THUNDERSTORMS POSSIBLE. WINDS AND SEAS WILL BE FAIRLY QUIET
OUTSIDE OF THUNDERSTORMS.

LONG TERM...

FRIDAY NIGHT - SATURDAY...WINDS AND SEAS MAY APPROACH SMALL CRAFT
ADVISORY CRITERIA.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$

NEAR TERM UPDATE... KIMBLE





AREA FORECAST DISCUSSION

NWS GRAY ME

 657 AM EDT TUE SEP 3 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST TODAY...
PROVIDING THE FOCUS FOR THUNDERSTORMS AGAIN THIS AFTERNOON. THE
FRONT WILL SWEEP OUT ALL THE WET AND HUMID WEATHER BY TONIGHT. A
SECOND COLD FRONT COMES THROUGH WEDNESDAY NIGHT...PROVIDING A
BRIEF SHOT OF MUCH COOLER AIR FOR THE END OF THE WEEK. HIGH
PRESSURE WILL BUILD ACROSS THE REGION LATE THURSDAY THROUGH
SATURDAY. ANOTHER COLD FRONT WILL CROSS NEW ENGLAND SATURDAY NIGHT
AND SUNDAY FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
HAVE UPDATED THE GRIDS TO ADD AREAS OF DRIZZLE ACROSS THE REGION
PER LATEST SURFACE OBSERVATIONS. THIS DRIZZLE AND AREAS OF FOG
WILL SLOWLY BE LIFTING AND MIXING OUT THIS MORNING. STILL EXPECT
SHOWERS AND THUNDERSTORMS TO ERUPT DURING THE MIDDAY PERIOD. A FEW
SHOWERS ASSOCIATED WITH THE FRONT ALREADY IN EASTERN NEW YORK
STATE EARLY THIS MORNING.

REST OF THE FORECAST PACKAGE WILL REMAIN RELATIVELY UNCHANGED.

PREV DISC...
LOW CLOUDS AND FOG WILL SLOWLY MIX OUT ACROSS THE REGION THIS
MORNING. EASTERN AREAS...ESPECIALLY NEAR THE COASTLINE...WILL BE
SLOW TO IMPROVE. IN THE MEANTIME...THE LATEST HRRR MODEL RUN
CONTINUES TO SHOW SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING OVER
EASTERN NEW HAMPSHIRE AROUND 17Z. THIS PRECIPITATION IS IN
ASSOCIATION WITH AN APPROACHING COLD FRONT. WITH APPROACHING UPPER
LEVEL TROUGH...WIND MAX AND MODEST INSTABILITY...EXPECT A FEW
STORMS TO CONTAIN DAMAGING WINDS OR HAIL.

HAVE THEREFORE ADDED ENHANCED WORDING TO THE FORECAST PACKAGE.
THUNDERSTORMS WILL CONTINUE UNTIL THIS EVENING...HOWEVER SOME OF
THE CONVECTIVE ACTIVITY WILL HAVE A CHALLENGING TIME MAKING IT
THROUGH ANY REMAINING LOW CLOUDS AND FOG ALONG THE MIDCOAST.

LOOK FOR 70S IN MOST AREAS...HOWEVER SOUTHERN NEW HAMPSHIRE MAY
TIP THE 80 DEGREE MARK.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
THE PRECIPITATION EXITS THE REGION THIS EVENING AS THE COLD FRONT
MOVES EAST. DRIER AIR WILL FILTER INTO THE FORECAST AREA FROM THE
WEST. HOWEVER...PLENTY OF LOW LEVEL MOISTURE FROM RECENT HEAVY
RAINS WILL ALLOW FOR MORE PATCHY FOG TO DEVELOP.

BY WEDNESDAY...THE UPPER LEVEL TROUGH WILL PUSH EAST OF THE
REGION...AND WE WILL BE IN BETWEEN SYSTEMS. A STRONG COLD FRONT
WILL APPROACH FROM THE WEST...BUT MUCH OF THE CLOUDINESS AND ANY
PRECIPITATION WILL HOLD OFF UNTIL AFTER DARK.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN THROUGH THE
FORECAST PERIOD. THE UPPER TROUGH LINGERS ACROSS THE REGION
THROUGH THE UPCOMING WEEKEND BEFORE THE UPSTREAM RIDGE ACROSS THE
INTERMOUNTAIN WEST FINALLY WEAKENS...AND THE FLOW BECOMES MORE
ZONAL ACROSS THE FORECAST AREA. WE BEGIN THE PERIOD WITH A
RELATIVELY DEEP TROUGH ACROSS THE AREA...AND A SURFACE COLD FRONT
MAKING ITS WAY SOUTHWARD ACROSS THE REGION WEDNESDAY NIGHT AND
EARLY THURSDAY. THIS FRONT WILL USHER BELOW NORMAL TEMPERATURES
INTO THE AREA FOR THURSDAY AND FRIDAY AS HIGH PRESSURE BUILDS
SOUTH AND EAST FROM THE GREAT LAKES. A RETURN FLOW AROUND THE
HIGH WILL INTRODUCE MILDER AIR INTO THE REGION SATURDAY. ANOTHER
SHORTWAVE WILL DRIVE A STRONG COLD FRONT ACROSS THE AREA SATURDAY
NIGHT AND SUNDAY WITH HIGH PRESSURE AND DRY AIR TO FOLLOW FOR
MONDAY.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...AREAS OF LOW CLOUDINESS AND FOG WILL SLOWLY MIX OUT
OVER THE REGION THIS MORNING...WITH THE LAST AREA TO CLEAR BEING EASTERN
AREAS THIS MORNING...ESPECIALLY NEAR THE COASTLINE. HOWEVER...THE
IMPROVEMENT WILL BE BRIEF WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AFT NOONTIME TODAY FROM WEST TO EAST. THE LOCALLY
STRONG SHOWERS AND STORMS WILL END THIS EVENING...FOLLOWED BY MORE
IFR AND ISOLATED LIFR CONDITIONS IN DEVELOPING FOG. VFR CONDITIONS
ON WEDNESDAY.

LONG TERM...

WED NIGHT - THU...SCT MVFR IN SHOWERS AND TSTMS.

&&

.MARINE...
SHORT TERM...A COLD FRONT WILL CROSS THE WATERS ON TODAY WITH
THUNDERSTORMS POSSIBLE AGAIN. WINDS AND SEAS WILL BE FAIRLY QUIET
OUTSIDE OF THUNDERSTORMS.

LONG TERM...

FRI NIGHT - SAT...WINDS AND SEAS MAY APPROACH SMALL CRAFT.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$





AREA FORECAST DISCUSSION

NWS HOUSTON/GALVESTON TX

 615 AM CDT TUE SEP 3 2013

.DISCUSSION...
SEE 12Z AVIATION DISCUSSION.

&&

.AVIATION...
NAM/GFS FCST SOUNDINGS SHOW PW VALUES APPROACHING 2.00 INCHES AND
K INDEX VALUES IN THE LOWER 40S. A WEAK BOUNDARY OVER NORTH TEXAS
WILL GRADUALLY SLIP SOUTH TODAY AND WILL LIKELY PROVIDE A LOW
LEVEL FOCUS FOR SHRA/TSRA. LEANED A BIT TOWARD THE TEXAS TECH WRF
AND THE HRRR WHICH SHOWS SCATTERED SHRA/TSRA DEVELOPING LATER THIS
MORNING THROUGH THIS EVENING. RAP 13 AND TEXAS TECH KEEPS THE
PRECIP GOING THROUGH 03Z WHILE THE NAM/GFS HINT AT POSSIBLE
CONVECTION PERSISTING THROUGH 09Z. 43

&&

.PREV DISCUSSION... /ISSUED 439 AM CDT TUE SEP 3 2013/

DISCUSSION...
MOSTLY CLEAR SKIES ACROSS THE SOUTHERN HALF OF SOUTHEAST TEXAS
THIS MORNING WITH PARTLY CLOUDY SKIES ACROSS THE NORTHERN HALF.
HAD SOME LIGHT SHOWERS IN GRIMES AND WALKER COUNTIES THIS MORNING
THAT HAVE FIZZLED.

TODAY THE BOUNDARY CURRENTLY LOCATED IN NORTHERN TEXAS WILL
CONTINUE TO PUSH SOUTHWARDS. THE DRIER DEWPOINTS IN NORTHERN
OKLAHOMA WILL NOT MAKE IT THIS FAR SOUTHWARDS BUT DRIER UPPER
LEVEL AIR WILL BEGIN TO FILTER DOWN INTO THE AREA LATER TODAY. AS
THE BOUNDARY SAGS SOUTHWARDS SCATTERED SHOWERS AND THUNDERSTORMS
WILL START TO DEVELOP IN THE NORTHERN COUNTIES THEN BEGIN TO FORM
ALONG THE SEA BREEZE LATER IN THE AFTERNOON. THERE IS ALSO A
SHORTWAVE CURRENTLY MAKING ITS WAY AROUND THE BASE OF AN UPPER
LEVEL TROUGH LOCATED IN THE GREAT LAKES REGION WHICH COULD ENHANCE
LIFT. LIFT WILL ALSO COME FROM 200 MB DIFFLUENCE AS SOUTHEAST
TEXAS LIES IN BETWEEN AN UPPER LEVEL TROUGH AND RIDGE. AS THE
DRIER AIR WORKS ITS WAY DOWN IT SHOULD START TO LIMIT
PRECIPITATION. GFS FORECAST SOUNDINGS SHOW PWATS APPROACHING 2.00"
AHEAD OF THE BOUNDARY (~1.60" AFTER DRIER AIR PASSES) WITH K
INDEX VALUES ABOVE 40. NAM FORECAST SOUNDINGS ARE SIMILAR WITH
SLIGHTLY HIGHER CAPE VALUES. DCAPE VALUES ALSO ARE AROUND 1000
J/KG WHICH SPELLS THE POSSIBILITY OF SOME STORMS PRODUCING STRONG
WINDS. GIVEN THE MECHANISMS OF LIFT MENTIONED ABOVE... INSTABILITY
AND MOISTURE IN PLACE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
SEEMS POSSIBLE TODAY.

ON WEDNESDAY DRIER AIR WILL MOST LIKELY LIMIT PRECIPITATION IN THE
NORTHERN HALF OF THE CWA AS THE DAY WANES THOUGH. NOT CONVINCED
THIS DRIER AIR WILL MAKE ITS WAY SOUTH OF I-10 SO WILL CONTINUE
SLIGHT PRECIP CHANCES IN THE SOUTHERN HALF OF THE CWA. BY
THURSDAY AN UPPER LEVEL LOW WILL MOVE INTO THE PACIFIC NORTHWEST
PUSHING THE UPPER LEVEL RIDGE EASTWARDS. CHANCES OF PRECIP LOOK TO
BE LIMITED LATER IN THE WEEK AS THE RIDGE MOVES TOWARDS US. BY
THE WEEKEND THE RIDGE WILL BEGIN TO WEAKEN SPELLING SLIGHTLY
COOLER TEMPERATURES OR MORE AVERAGE TEMPERATURES FOR THIS TIME OF
YEAR. 23

MARINE...
NO FCST ISSUES. LIGHT WINDS & LOW SEAS EXPECTED AS A WEAK BOUNDARY
SLIPS INTO SE TX. 43

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      96  75  98  75  99 /  40  20  10  10  10
HOUSTON (IAH)              97  76  97  76  97 /  40  30  20  10  20
GALVESTON (GLS)            90  81  90  81  90 /  30  20  20  10  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

DISCUSSION...23
AVIATION/MARINE...43




AREA FORECAST DISCUSSION

NWS SPOKANE WA

 614 AM PDT Tue Sep 3 2013

.SYNOPSIS...
Showers and thunderstorms will persist over the Inland Northwest
today and Wednesday. Some storms could be severe. A large area of
low pressure will move over the region for the end of the week,
leading to the potential for widespread heavy rain on Thursday and
continuing through Saturday. A drying and warming trend is
expected by the beginning of next week


&&

.DISCUSSION...
The forecast for today has been updated mainly for this morning
based on current satellite and radar trends. Despite favorable mid
level instability for convective development...lack of large scale
forcing has kept most of the Inland Northwest dry as of 6 am.
Latest HRRR and 06z 4km NAM shows the bulk of the showers this
morning from the Blues into the Central Panhandle Mountains, and
near the Cascades. Latest trends support this so POPs were lowered
for the morning for most areas along with the remove of
thunderstorms during the morning all areas except in and near the
Cascades.  JW

&&

.AVIATION...
12Z TAFS: Moist southerly flow ahead of an upper level low
pressure off the coast will continue to promote mid level and high
level ceilings across the forecast area through the next 24 hours. A
wave rounding the base of the upper low will trigger scattered
showers and isolated thunderstorms today. Thunderstorms will mainly
occur after 18Z after the air mass becomes increasingly unstable
from surface based heating leading. VFR conditions are expected at
all TAF sites outside of thunderstorm cores.  Some drying aloft
moves in between 0-6z Wednesday which combined with loss of daytime
heating should result in showers/thunderstorms quickly diminishing.
However another wave approaches late tonight with main threat for
additional convection holding off til after 12z Wednesday.  JW


&&

.PREV DISCUSSION... /ISSUED 501 AM PDT Tue Sep 3 2013/

..Strong to locally severe thunderstorms possible this afternoon
and again Wednesday afternoon...
..Heavy rainfall expected Thursday...

Today through Wednesday...Large closed low near 130W will remain
in place through Wednesday afternoon. This will result in a moist
and unstable southerly flow with scattered showers and
thunderstorms. Precipitable water values of 150-225 percent of
normal will support wet storms producing locally heavy rain. Storm
motions however of around 15-20 mph should limit the threat for
flash flooding through Wednesday although if any training cells
develop this could heighten the risk.

For today a short wave moving into western Oregon early this
morning will move north into the Washington Cascades by
afternoon...exiting into British Columbia during the afternoon.
Increased lift with this wave will lead to an increase in showers
across Central Washington this morning especially the Cascades.
Meanwhile monsoonal moisture will continue to work its way up into
Eastern Washington and North Idaho this morning which combined
with weak lift from the wave tracking to the west will lead to an
increase in showers as well. Meanwhile mid level instability could
trigger a few thunderstorms over the region this morning with the
best chances in the Cascades given stronger lift. Then for the
afternoon abundant low level moisture and some sun breaks should
allow for the atmosphere to destabilize further with GFS showing
uncapped CAPE values of 300-800 J/KG and the NAM 600-1200 J/KG.
This combined with 0-6km wind shear values of 30-50 knots (highest
near the Cascades) may lead to strong to locally severe storms
especially if the higher NAM CAPE values pan out. A combination of
drier air aloft and loss of day time heating should result in
convection quickly diminishing this evening.

Then late tonight into Wednesday another wave moves up from the
south bringing another round of convection. Confidence is low at
this time regarding areas with best instability with big
differences between the GFS and NAM especially over North Idaho.
However ECMWF and GFS show the best chances for thunderstorms in
the Cascades given closer proximity to low off the coast with good
upper level diffluence in this area. Shear values will again be
supportive for strong to locally severe storms.  JW

Wednesday evening through next Tuesday...Through this portion of
the forecast period model guidance is similar showing a deep
closed low tracking from off the Oregon coast north along the
Cascades and then east across eastern WA on Sunday. While there
are some timing issues the models all indicate a very active and
very wet pattern through the weekend. By Monday and Tuesday the
upper low will eject east of the Rockies with high pressure
building in the eastern Pacific.

A moist and very unstable air mass will be over the Pac NW
Wednesday evening and any convection from Wednesday afternoon will
continue through at least the early evening hours.

Thursday through Friday will be the most active period as the
front tracks trough the region. The front is expected to move
north off the Oregon Cascades early Thursday morning and finally
eject east and out of the area Friday morning. The front will act
as a strong lifting mechanism and combine with upper level support
from the passing jet. Abundant Pacific moisture will be available
as southerly flow will increase PWATs to around 1.50 inches,
which is above 200 percent of normal. In addition the atmosphere
will become increasingly unstable. This convective nature will
result in showers and embedded thunderstorms with the potential of
widespread very heavy rain along the front as it moves through the
region. WPC has indicated the possibility of outing the area in an
excessive rainfall area from 12z Thursday- 12z Friday. As we get
nearer to this event there will most likely be flash flood watches
across the area. High cape values and decent 0-6km shear hints at
the possibility of some storms becoming better organized then what
we normally see in early September for the chance of strong
outflow winds and large hail.

Late Friday behind the front there should be drying from the
southwest. Saturday and Sunday the cold core will track across the
Inland Northwest. This will keep the atmosphere very unstable and
with lingering moisture we can expect showers and embedded
thunderstorms just about anywhere east of the Cascades.

By early Monday the upper level low will have ejected east of the
divide and high pressure will begin to build in the eastern Pacific.
This will result in a drier northwest flow. Afternoon heating and
up-sloping flow will support some chances of showers across the
Idaho Panhandle mountains...otherwise the forecast will be dry.
Temperatures below normal through Saturday will begin to rebound
Sunday with temperatures rising to a few degrees above normal by
Monday and Tuesday. /Tobin

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        80  62  88  64  74  56 /  40  20  50  50  80  80
Coeur d`Alene  79  60  87  61  74  55 /  50  20  60  40  80  90
Pullman        80  59  88  62  75  51 /  50  20  50  50  80  70
Lewiston       86  65  93  68  82  60 /  60  20  50  40  80  60
Colville       84  55  91  59  79  55 /  50  30  60  60  90  90
Sandpoint      76  53  86  59  74  54 /  70  20  50  40  80 100
Kellogg        76  59  85  59  75  53 /  70  40  60  30  80  90
Moses Lake     87  59  89  65  76  56 /  20  10  30  60  90  50
Wenatchee      84  63  85  65  74  59 /  40  20  40  70  90  60
Omak           84  59  87  63  78  58 /  60  20  70  70  90  90

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...&&

$$









AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 250 PM MST TUE SEP 3 2013


.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...
SHOWER AND SOME THUNDERSTORMS ARE NOW DEVELOPING ACROSS FAR EASTERN
ARIZONA AND NEAR TUCSON AS OF JUST AFTER NOON. EXPECTING THIS
ACTIVITY TO BECOME MORE WIDESPREAD THROUGHOUT THE AFTERNOON AS IT
MOVES TO THE WEST AND LIKELY AFFECTING THE METRO PHOENIX AREA
BETWEEN 00-04Z TODAY. EXPECT BLOWING DUST FROM STORM
OUTFLOWS...GUSTY WINDS AND HEAVY RAIN POSSIBLE WITH STORMS THAT DO
DEVELOP THIS EVENING.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EXPECT TODAY TO BE QUIETER IN TERMS OF WEATHER COMPARED TO YESTERDAY
WITH STORM DEVELOPMENT MAINLY FOCUSED ACROSS CENTRAL ARIZONA LATER
THIS AFTERNOON AND EVENING. THIS ACTIVITY COULD DRIFT NEAR THE KBLH
TERMINAL THROUGH THE EVENING.

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...KUHLMAN
FIRE WEATHER...NOLTE/KUHLMAN







AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 1233 PM MST TUE SEP 3 2013

.UPDATE...UPDATED AVIATION DISCUSSION.

&&

.SYNOPSIS...
MONSOON MOISTURE CONTINUES TO BE SPREAD OVER THE REGION...WITH A
CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. THE BEST CHANCE OF THUNDERSTORMS WILL BE OVER SOUTH CENTRAL
ARIZONA...INCLUDING PHOENIX...AS A WEATHER DISTURBANCE MOVING OUT OF
WEST TEXAS HELPS TO INCREASE THE THUNDERSTORMS THREAT TODAY AND
TONIGHT. THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND WITH SEE A
REDUCED THREAT OF THUNDERSTORMS...ALONG WITH WARMER AFTERNOON
TEMPERATURES.

&&

.DISCUSSION...
CLEAR SKIES AS OF MID MORNING OVER THE FORECAST AREA IS ALLOWING
SURFACE HEATING TO PROGRESS. SATELLITE IMAGERY SHOWS A NORTH-SOUTH
ORIENTED BAND OF CLOUDINESS NEAR THE AZ/NM BORDER AND APPEARS TO BE
ASSOCIATED WITH A DIFLUENT AREA AHEAD OF AN APPROACHING SHORT WAVE
CURRENTLY OVER FAR WEST TEXAS. A LARGER INVERTED TROUGH IS CENTERED
WELL SOUTHEAST OF THAT. MOISTURE TRENDS OVERNIGHT AND THIS MORNING
HAVE BEEN A MIXED BAG WHEN LOOKING AT GPS IPW DATA. BOTH THE NAM AND
GFS SHOW 1000-700 MB MEAN MIXING RATIOS DECREASING DURING THE DAY
DESPITE THE ARRIVAL OF THE SHORT WAVE...THOUGH SOME OF THAT MAY BE
ATTRIBUTED TO THE DIURNAL CYCLE. BOTH MODELS HAVE THE AXIS OF THE
SHORT WAVE AT 250 MB CLOSE TO THE AZ/NM BORDER AT 00Z THIS
AFTERNOON. THEY ALSO SHOW A BATCH OF UPPER LEVEL DIVERGENCE OVER
EASTERN PORTIONS OF THE FORECAST AREA...MAINLY ZONE 24 DEVELOPING
THIS AFTERNOON. THE NAM A BIT FASTER...21Z...THAN THE GFS...00Z.
HOWEVER...IT APPEARS TO BE RELATIVELY SHORT LIVED AND DISSIPATES
OVER SOUTHEAST ARIZONA DURING THE EVENING. DIVERGENCE FIELDS NOT
OVERLY IMPRESSIVE BUT SHOULD HELP MAKE STORM DEVELOPMENT EASIER OVER
THE HIGHER TERRAIN. HRRR MODEL SHOWS ISOLATED STORM DEVELOPMENT OVER
OUR AREA THIS AFTERNOON BEFORE BECOMING MORE WIDESPREAD THIS EVENING
OVER SOUTH-CENTRAL ARIZONA. MEANWHILE...BOTH THE 06Z VERSIONS OF THE
NMM6KM AND LOCAL WRF SHOW VERY LITTLE FOR THIS AFTERNOON/EVENING.
SAME IS TRUE FOR RUC/RAP. THIS LOOKS UNDERDONE AND THUS PLAN ON
HOLDING ON TO ELEVATED POPS FOR TONIGHT. WILL CONTINUE TO EVALUATE.

&&

.PREVIOUS DISCUSSION ISSUED AT 300 AM...
TODAY AND TONIGHT...
MONSOON MOISTURE CONTINUED TO BE SPREAD OVER THE REGION THIS
MORNING...WITH ANOTHER THREAT OF AFTERNOON AND EVENING THUNDER-
STORMS. HOWEVER THE BEST CHANCE OF STORMS WILL DEVELOP OVER SOUTH
CENTRAL ARIZONA...INCLUDING PHOENIX AND CASA GRANDE...AS AN INVERTED
TROF FROM WEST TEXAS MOVES INTO SOUTHEAST AZ THIS AFTERNOON AND
EVENING.  THIS FEATURE CAN BE SEEN IN WATER VAPOR IMAGERY THIS
MORNING...WITH THE NORTH/SOUTH BAND OF CLOUDS AND ISOLATED
THUNDERSTORMS IN WESTERN NEW MEXICO HIGHLIGHTING THE DEFORMATION
ZONE ASSOCIATED WITH ITS LEADING EDGE. THEREFORE THE HIGHEST PRECIP
PROBABILITIES TODAY ARE FORECAST IN SOUTH CENTRAL ARIZONA. IT IS
ALSO EXPECTED THAT CONSIDERABLE CONVECTIVE DEBRIS CLOUDS AND
ISOLATED SHOWERS/THUNDERSTORMS WILL CONTINUE TO MOVE WESTWARD...AND
INTO PORTIONS OF SOUTHWEST ARIZONA OVERNIGHT.

WEDNESDAY THROUGH MONDAY...
WE WILL BE SHIFTING INTO A SLIGHTLY DRIER AND MORE STABLE FLOW
REGIME THIS PERIOD. HOWEVER A FEW WEAK UPPER LEVEL PERTURBATIONS ARE
FORECAST TO MOVE INTO AZ FROM NORTHWEST MEXICO SOMETIME THU OR FRI.
THEREFORE WE WILL GO WITH A LOW GRADE MONSOON...MEANING ONLY A
SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS.


&&

.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SHOWER AND SOME THUNDERSTORMS ARE NOW DEVELOPING ACROSS FAR EASTERN
ARIZONA AND NEAR TUCSON AS OF JUST AFTER NOON. EXPECTING THIS
ACTIVITY TO BECOME MORE WIDESPREAD THROUGHOUT THE AFTERNOON AS IT
MOVES TO THE WEST AND LIKELY AFFECTING THE METRO PHOENIX AREA
BETWEEN 00-04Z TODAY. EXPECT BLOWING DUST FROM STORM
OUTFLOWS...GUSTY WINDS AND HEAVY RAIN POSSIBLE WITH STORMS THAT DO
DEVELOP THIS EVENING.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
EXPECT TODAY TO BE QUIETER IN TERMS OF WEATHER COMPARED TO YESTERDAY
WITH STORM DEVELOPMENT MAINLY FOCUSED ACROSS CENTRAL ARIZONA LATER
THIS AFTERNOON AND EVENING. THIS ACTIVITY COULD DRIFT NEAR THE KBLH
TERMINAL THROUGH THE EVENING.

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
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...KUHLMAN
FIRE WEATHER...NOLTE/KUHLMAN










AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 1030 AM MST TUE SEP 3 2013


.SYNOPSIS...
MONSOON MOISTURE CONTINUES TO BE SPREAD OVER THE REGION...WITH A
CHANCE OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. THE BEST CHANCE OF THUNDERSTORMS WILL BE OVER SOUTH CENTRAL
ARIZONA...INCLUDING PHOENIX...AS A WEATHER DISTURBANCE MOVING OUT OF
WEST TEXAS HELPS TO INCREASE THE THUNDERSTORMS THREAT TODAY AND
TONIGHT. THE REMAINDER OF THE WEEK AND UPCOMING WEEKEND WITH SEE A
REDUCED THREAT OF THUNDERSTORMS...ALONG WITH WARMER AFTERNOON
TEMPERATURES.

&&

.DISCUSSION...
CLEAR SKIES AS OF MID MORNING OVER THE FORECAST AREA IS ALLOWING
SURFACE HEATING TO PROGRESS. SATELLITE IMAGERY SHOWS A NORTH-SOUTH
ORIENTED BAND OF CLOUDINESS NEAR THE AZ/NM BORDER AND APPEARS TO BE
ASSOCIATED WITH A DIFLUENT AREA AHEAD OF AN APPROACHING SHORT WAVE
CURRENTLY OVER FAR WEST TEXAS. A LARGER INVERTED TROUGH IS CENTERED
WELL SOUTHEAST OF THAT. MOISTURE TRENDS OVERNIGHT AND THIS MORNING
HAVE BEEN A MIXED BAG WHEN LOOKING AT GPS IPW DATA. BOTH THE NAM AND
GFS SHOW 1000-700 MB MEAN MIXING RATIOS DECREASING DURING THE DAY
DESPITE THE ARRIVAL OF THE SHORT WAVE...THOUGH SOME OF THAT MAY BE
ATTRIBUTED TO THE DIURNAL CYCLE. BOTH MODELS HAVE THE AXIS OF THE
SHORT WAVE AT 250 MB CLOSE TO THE AZ/NM BORDER AT 00Z THIS
AFTERNOON. THEY ALSO SHOW A BATCH OF UPPER LEVEL DIVERGENCE OVER
EASTERN PORTIONS OF THE FORECAST AREA...MAINLY ZONE 24 DEVELOPING
THIS AFTERNOON. THE NAM A BIT FASTER...21Z...THAN THE GFS...00Z.
HOWEVER...IT APPEARS TO BE RELATIVELY SHORT LIVED AND DISSIPATES
OVER SOUTHEAST ARIZONA DURING THE EVENING. DIVERGENCE FIELDS NOT
OVERLY IMPRESSIVE BUT SHOULD HELP MAKE STORM DEVELOPMENT EASIER OVER
THE HIGHER TERRAIN. HRRR MODEL SHOWS ISOLATED STORM DEVELOPMENT OVER
OUR AREA THIS AFTERNOON BEFORE BECOMING MORE WIDESPREAD THIS EVENING
OVER SOUTH-CENTRAL ARIZONA. MEANWHILE...BOTH THE 06Z VERSIONS OF THE
NMM6KM AND LOCAL WRF SHOW VERY LITTLE FOR THIS AFTERNOON/EVENING.
SAME IS TRUE FOR RUC/RAP. THIS LOOKS UNDERDONE AND THUS PLAN ON
HOLDING ON TO ELEVATED POPS FOR TONIGHT. WILL CONTINUE TO EVALUATE.

&&

.PREVIOUS DISCUSSION ISSUED AT 300 AM...
TODAY AND TONIGHT...
MONSOON MOISTURE CONTINUED TO BE SPREAD OVER THE REGION THIS
MORNING...WITH ANOTHER THREAT OF AFTERNOON AND EVENING THUNDER-
STORMS. HOWEVER THE BEST CHANCE OF STORMS WILL DEVELOP OVER SOUTH
CENTRAL ARIZONA...INCLUDING PHOENIX AND CASA GRANDE...AS AN INVERTED
TROF FROM WEST TEXAS MOVES INTO SOUTHEAST AZ THIS AFTERNOON AND
EVENING.  THIS FEATURE CAN BE SEEN IN WATER VAPOR IMAGERY THIS
MORNING...WITH THE NORTH/SOUTH BAND OF CLOUDS AND ISOLATED
THUNDERSTORMS IN WESTERN NEW MEXICO HIGHLIGHTING THE DEFORMATION
ZONE ASSOCIATED WITH ITS LEADING EDGE. THEREFORE THE HIGHEST PRECIP
PROBABILITIES TODAY ARE FORECAST IN SOUTH CENTRAL ARIZONA. IT IS
ALSO EXPECTED THAT CONSIDERABLE CONVECTIVE DEBRIS CLOUDS AND
ISOLATED SHOWERS/THUNDERSTORMS WILL CONTINUE TO MOVE WESTWARD...AND
INTO PORTIONS OF SOUTHWEST ARIZONA OVERNIGHT.

WEDNESDAY THROUGH MONDAY...
WE WILL BE SHIFTING INTO A SLIGHTLY DRIER AND MORE STABLE FLOW
REGIME THIS PERIOD. HOWEVER A FEW WEAK UPPER LEVEL PERTURBATIONS ARE
FORECAST TO MOVE INTO AZ FROM NORTHWEST MEXICO SOMETIME THU OR FRI.
THEREFORE WE WILL GO WITH A LOW GRADE MONSOON...MEANING ONLY A
SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS.


&&

.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
ISOLATED THUNDERSHOWER ACTIVITY WILL CONTINUE TO PERCOLATE NORTHWARD
ACROSS THE PHOENIX METRO THIS MORNING...GENERATING LIGHT SHOWER AND
VERY BRIEF VARIABLE BREEZINESS. THESE SHOWERS SHOULD DISSIPATE
THROUGH THE MID MORNING. EXPECT MOSTLY SCT CLOUD COVER TO LINGER
THROUGH THE DAY BEFORE MORE SUBSTANTIAL CB DEVELOPMENT COVERS THE
EASTERN AND SOUTHEASTERN HORIZONS. EARLY AFTERNOON WINDS MAY FAVOR
MORE SOUTHERLY HEADINGS THAN ANY WEST COMPONENT...ESPECIALLY FOR
KPHX. MEDIUM CONFIDENCE IN STORM ACTIVITY BUILDING AND MOVING INTO
PHOENIX THIS AFTERNOON...AND INTRODUCED VCSH FOR KPHX AND SHORT
WINDOWS OF VCTS FOR KIWA AND KSDL FOLLOWED BY ADDITIONAL VCSH AFTER
04/00Z. EXPECT BLOWING DUST FROM STORM OUTFLOWS...GUSTY WINDS AND
HEAVY RAIN POSSIBLE WITH STORMS THAT DO DEVELOP THIS EVENING.

SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
LIGHT AND VARIABLE MORNING WINDS WILL TURN WESTERLY FOR KIPL AND
EASTERLY FOR KBLH THROUGH THE DAY. EXPECT SCT TO BKN CLOUD COVER TO
PERSIST THROUGH THE DAY WITH CIGS AOA 15KFT OR GREATER. GIVEN STORM
ACTIVITY ACROSS THE REGION MONDAY EVENING...EXPECT TODAY TO BE
QUIETER IN TERMS OF WEATHER...LEAVING MENTION OF WEATHER OUT OF KIPL
AND ONLY VCSH MENTION IN KBLH FOR THE LATE EVENING. STORM
DEVELOPMENT IS EXPECTED ACROSS CENTRAL ARIZONA LATER THIS AFTERNOON
AND EVENING AND MAY DRIFT NEAR THE KBLH TERMINAL THROUGH THE
EVENING.

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. 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
PREVIOUS DISCUSSION...VASQUEZ
AVIATION...NOLTE
FIRE WEATHER...NOLTE/PERCHA







AREA FORECAST DISCUSSION

NWS GRAND JUNCTION CO

 1059 AM MDT TUE SEP 3 2013

.UPDATE...
ISSUED AT 1057 AM MDT TUE SEP 3 2013

CLOUD PLUME EXTENDED ALONG THE AZ/NM BORDER UP INTO SE UT/SW CO
THIS MORNING. LOOKED LIKE A WEAK SHORTWAVE WAS PUSHING INTO SE UT
ON SATELLITE WATER VAPOR...WHICH THE RUC13 CAPTURED REASONABLY
WELL AND TRACKS IT N-NE AS IT WEAKENS. WILL ADD MENTION OF
ISOLATED STORMS TO NW CO TODAY...OTHERWISE CURRENT FORECAST LOOKS
ON TRACK WITH ISOLATED TO SCATTERED STORMS MAINLY OVER THE HIGHER
TERRAIN FROM FROM THE UINTA MTNS TO FLATTOPS AND SOUTH THIS
AFTERNOON. LOCALLY HEAVY RAINFALL POSSIBLE GIVEN DECENT MOISTURE
AND SLOW STORM MOVEMENT.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 429 AM MDT TUE SEP 3 2013

STAGNANT PATTERN WHICH FEATURED HIGH PRESSURE CENTERED OVER THE
COLORADO SPRINGS AREA WILL PERSIST TODAY. AS A RESULT...A WEAK
INFLUX OF MONSOON MOISTURE ALONG WITH SOME RECYCLING OF MOISTURE
OVER THE REGION WILL CONTINUE. EARLY THIS MORNING...A WEAK
DISTURBANCE MOVING OVER SOUTHEAST UTAH WAS RESPONSIBLE FOR A FEW
THUNDERSTORMS STRETCHING FROM MEXICAN HAT TO THE NORTHWEST FLANKS
OF THE ABAJO MOUNTAINS. ANOTHER DISTURBANCE FARTHER SOUTH HAS THE
POTENTIAL OF PROLONGING THIS ACTIVITY WHILE POSSIBLE IMPACTING
PORTIONS OF SOUTHWEST COLORADO AS WELL. MODEL CONSENSUS FAVORED
SOME LIGHT SHOWERS AND A FEW EMBEDDED THUNDERSTORMS LINGERING OVER
THIS AREA PAST SUNRISE AND THEREFORE BOOSTED LOW END POPS THIS
MORNING.

FROM LATE MORNING INTO THE AFTERNOON...DIURNAL PROCESSES WILL TAKE
OVER WITH STORMS DEVELOPING OVER THE HIGH TERRAIN. MAIN THREAT
FROM TODAY/S STORMS WILL BE HEAVY RAIN AS PRECIPITABLE WATER
VALUES RANGE FROM 0.8 TO NEAR 1.0 INCH ACROSS REGION. LIGHT FLOW
WILL RESULT IN SLOW MOVING STORMS WHICH COULD RESULT IN LOCALIZED
RUNOFF ISSUES...ESPECIALLY OVER BURN SCARS AND STEEP TERRAIN.

EXPECT LITTLE CHANGE IN AFTERNOON HIGHS FOR THE REGION...THOUGH
TIMING AND PLACEMENT OF DEVELOPING STORM CELLS WILL RESULT LOCAL
DEVIATIONS.

H5 00Z HAND ANALYSIS HAD THE CENTER OF THE SUBTROPICAL HIGH NOSING
ACROSS THE CENTRAL NM/CO BORDER. THE HIGH WILL BE MAKING ROOTS IN
CENTRAL COLORADO OVER THE NEXT SEVERAL DAYS AS STRONG TROUGHING
ALONG EACH NORTHERN COAST OF THE CONUS STAGNATES THE WX PATTERN.
WATER VAPOR IMAGERY SHOWED DRIER AIR IN THE PLAINS BEHIND A COLD
FRONT PROGRESSING THROUGH THE EASTERN TROUGH. THIS DRIER AIR WILL
BE ADVECTED EASTWARD AROUND THE BASE OF THE HIGH AND EFFECTIVELY
CUTTING OFF THE DIRECT FLOW OF MONSOONAL MOISTURE INTO OUR CWA.
MOISTURE HOWEVER WILL SATURATE THE CENTER OF THE HIGH PRESSURE
CELL OVER COLORADO AND PROVIDE ENOUGH FUEL TO FIRE MAINLY
DIURNALLY DRIVEN CONVECTION THROUGH THE MID WEEK PERIOD. OUR CWA
WILL BE ON THE WESTERN AXIS OF THE HIGH SO STORM MOTION WILL
GENERALLY BE FROM THE SOUTH TO SOUTHWEST AT 15 MPH OR LESS. WITH
THE WARMER TEMPERATURES ALOFT INSTABILITY...THEREFORE CAPE...WILL
BE LIMITED TO A SMALL PORTION OF THE PROFILE AND STORMS SHOULD NOT
BE ORGANIZED. THIS SHOULD FAVOR THE TERRAIN FOR STORM FORMATION
WITH ONLY A FEW ISOLATED STORMS SURVIVING INTO THE VALLEYS FROM
FAVORABLE OUTFLOW INTERACTIONS. BRIEF MODERATE TO HEAVY RAINFALL
WILL BE POSSIBLE BUT DEEP CONVECTION SHOULD BE LIMITED UNDER THE
SUBSIDENCE OF THE HIGH PRESSURE. HIGH TEMPERATURES WILL BE WELL
ABOVE NORMAL AND FOR NOW DO NOT LOOK TO STRAY TO FAR FROM
PERSISTENCE WEDNESDAY INTO THURSDAY. MEANING HIGHS IN THE 90S
LOWER VALLEYS...WITH MID 60S TO MID 70S OVER THE MOUNTAINS.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 429 AM MDT TUE SEP 3 2013

THE LOW PRESSURE SYSTEM ANCHORED OFF THE PACIFIC NORTHWEST OVER
THE PAST SEVERAL DAYS WILL BEGIN TO DRIFT INLAND THURSDAY NIGHT...
MOVING SLOWLY EASTWARD ACROSS THE NORTHWEST INTO MONDAY. THIS
WON/T BRING AN APPRECIABLE CHANGE IN WEATHER ACROSS THE REGION AS
FLOW BETWEEN THE NORTHWEST LOW AND THE SOUTHERN PLAINS CONTINUES
TO CARRY MONSOON MOISTURE ACROSS THE REGION LATE THIS WEEK...
THROUGH THE WEEKEND...AND INTO EARLY NEXT WEEK. AS A RESULT...
EXPECT MAINLY DIURNAL SHOWERS AND THUNDERSTORMS WILL CONTINUE
THROUGH THE PERIOD WITH LOCALLY HEAVY RAIN THE MAIN STORM THREAT.
CONSEQUENTLY...TEMPERATURES WILL CONTINUE TO RUN NEAR AND A LITTLE
ABOVE NORMAL THROUGH THE PERIOD.

HOWEVER...AS THE TROUGH PASSES TO THE NORTH OF THE AREA SUNDAY
NIGHT INTO MONDAY...MODELS HINT AT A COOL FRONT DROPPING OVER THE
NORTHERN HALF OF THE FORECAST AREA. ALONG WITH MILDER TEMPERATURES
BEHIND THE FRONT...DRIER AIR WILL LIMIT AFTERNOON CONVECTION NORTH
OF THE I-70 CORRIDOR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1057 AM MDT TUE SEP 3 2013

ISOLATED TO SCATTERED THUNDERSTORMS CAN BE EXPECTED MAINLY OVER
THE HIGHER TERRAIN BETWEEN 18Z AND 02Z TODAY...THOUGH WITH A SLOW
NORTHEAST STORM MOTION EXPECTED...WILL ALSO CARRY VCTS AT KRIL
AND KEGE. BRIEF MVFR OR POSSIBLY IFR VISIBLITY IS POSSIBLE IN
HEAVY RAIN FROM THE STRONGER STORMS. STORMS WILL DIMINISH DURING
THE LATTER PART OF THE EVENING THOUGH ISOLATED LIGHT SHOWERS WILL
CONTINUE INTO WEDNESDAY MORNING. SHOWER INTENSITY WILL BE LIGHT SO
VFR CONDITIONS WILL PREVAIL FROM 06Z TO 12Z.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.

UT...NONE.

&&

$$

UPDATE...JAD
SHORT TERM...NL/15
LONG TERM...NL
AVIATION...TGJT








AREA FORECAST DISCUSSION...UPDATED

NWS PEACHTREE CITY GA

 120 PM EDT TUE SEP 3 2013

.PREV DISCUSSION... /ISSUED 953 AM EDT TUE SEP 3 2013/

UPDATE...
WEAK COLD FRONT MOVING INTO N GA. BEST CHANCES FOR SHOWERS AND
STORMS APPEAR TO BE S OF FRONT ACROSS CENTRAL AND PORTIONS OF N
GA THIS AFTERNOON WHERE BEST INSTABILITY IS FORECAST. BDL

PREV DISCUSSION... /ISSUED 729 AM EDT TUE SEP 3 2013/

SHORT TERM /TODAY THROUGH WEDNESDAY/...
DEEP UPPER TROUGH IN PLACE OVER THE EASTERN HALF OF THE COUNTRY...
WITH THE TROUGH AXIS PARALLEL TO THE SOUTHERN APPALACHIANS AT THE
START OF THE SHORT TERM. ASSOCIATED SURFACE FRONT CURRENTLY LOCATED
FROM NEAR THE UPPER OHIO VALLEY...STRETCHING THROUGH THE MID-SOUTH
AND TO NEAR THE RED RIVER AT AFD TIME. THE FRONT WILL WORK ITS WAY
SOUTHEAST THROUGH THE DAY...WITH DRIER AIR BEGINNING TO FILTER INTO
THE STATE FOR TONIGHT. SHORT-TERM GUIDANCE IS IN PRETTY GOOD
AGREEMENT WITH THE MASS FIELDS. NOT A LOT OF SYNOPTIC LIFT TO SPEAK
OF TODAY AS THE FRONT CONTINUES TO OCCLUDE...BUT THERE SHOULD BE AT
LEAST SOME SYNOPTIC CONTRIBUTION IN THE FORM OF WEAK DIVERGENCE
ALOFT /RIGHT ENTRANCE REGION OF THE BARELY-THERE UPPER JET/ AND OF
COURSE DPVA AHEAD OF THE SHORTWAVE ITSELF...BOTH OF THESE MAXIMIZED
ACROSS CENTRAL GEORGIA FOR THIS AFTERNOON.

OF IMMEDIATE CONCERN IS THE EVOLUTION OF CONVECTION THROUGH THE
EARLY MORNING HOURS. PRE-FRONTAL CONVECTION HAS FIRED ACROSS
NORTHWEST GEORGIA AT AFD TIME...AND IN SIMILAR MANNER TO YESTERDAY
MORNING THE CONVECTION FIRED ALONG AN INSTABILITY GRADIENT IN AN
AREA WHERE CIN IS MINIMIZED. LATEST RUNS OF THE HRRR ARE ACTUALLY
PICKING UP ON THIS AND PUSHING A CONVECTIVE COMPLEX ACROSS NORTH
GEORGIA BETWEEN NOW AND APPROXIMATELY 13Z. BASED ON WHAT HAPPENED
LAST NIGHT...THIS IS NOT AT ALL AN UNREASONABLE SOLUTION...AND OTHER
HIRES GUIDANCE POINTING TO THE SAME THING. ARW MEMBERS NOT QUITE SO
PRONOUNCED AS THE NMM THOUGH. HRRR HAS NOT BEEN DOING WELL THE PAST
FEW DAYS BUT PERHAPS IT HAS FINALLY CAUGHT UP...AND IN ANY CASE THE
OVERALL PATTERN IS SUPPORTIVE OF DEVELOPMENT OF THESE OVERNIGHT
CONVECTIVE COMPLEXES. AS WAS THE CASE YESTERDAY...WHATEVER DOES
DEVELOP ACROSS NORTH GEORGIA EARLY THIS MORNING WILL LIKELY
DISSIPATE BY MID-MORNING /AFTER SUNRISE/ AS MIXING INCREASES.
HOWEVER...IF SUCH A CONVECTIVE COMPLEX DEVELOPS /AS IT DID
YESTERDAY/...IT WILL LIKELY WREAK HAVOC ON HIGH TEMPS TODAY /AS IT
DID YESTERDAY/. AT THIS POINT IT IS NEARLY IMPOSSIBLE TO TRY TO PIN
DOWN THOSE DETAILS BUT SUFFICE IT TO SAY THAT WE COULD SEE SOME BIG
BUSTS AGAIN TODAY /AS WE DID YESTERDAY/.

CAPES INCREASE TO BETWEEN 1500-2000 J/KG THIS AFTERNOON AHEAD OF THE
FRONT...MAINLY FROM APPROXIMATELY THE ATLANTA METRO AREA AND POINT
SOUTH. EXPECT CONVECTION TO FIRE AGAIN THIS AFTERNOON WITH BEST
COVERAGE ACROSS CENTRAL GEORGIA BUT ISOLATED TO SCATTERED CONVECTION
POSSIBLE UP INTO THE METRO AREA. EXPECT THE BULK IF NOT ALL OF THE
ACTIVITY TO DIE DOWN BY 06Z AND THUS HAVE NO POPS ACROSS THE AREA
OVERNIGHT. THE FRONT WILL CONTINUE TO SAG SOUTH AND WE SHOULD SEE A
NOTICEABLE DIFFERENCE IN LOW TEMPS BETWEEN WHAT WE HAVE THIS MORNING
AND TONIGHT...GENERALLY DOWN 3-5 DEGREES.

FRONT SHOULD STALL SOMEWHERE ACROSS THE AREA ON WEDNESDAY...KEEPING
THE CHANCE FOR CONVECTION ACROSS CENTRAL GEORGIA MAINLY DURING THE
AFTERNOON. INFLUENCE OF DRIER AIR WILL BE FELT ACROSS NORTH GEORGIA
BUT NO REAL CAA ALOFT TO SPEAK OF SO DO NOT THINK THAT TEMPS
WEDNESDAY WILL BE MUCH IF AT ALL COOLER THAN THOSE TODAY. /AND
ACTUALLY IF WE HAVE RAIN-COOLED AIR FROM CONVECTION THIS MORNING
MESSING WITH TEMPS TODAY...THEN WEDNESDAY COULD ACTUALLY BE WARMER./
ALL THAT SAID...WENT WITH A GENERAL BIAS-ADJUSTED BLEND.

TDP

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...

MODELS CONSISTENT IN KEEPING DRY AIR ACROSS NORTH GEORGIA THROUGH
THE END OF THE WEEK AS THE FRONTAL BOUNDARY STALLS JUST SOUTH OF
THE CWA. DRYING ALOFT AND LOW PRECIPITABLE WATER SHOULD KEEP
CONVECTION OUT OF MUCH OF THE CWA THROUGH THURSDAY NIGHT...EXCEPT
FOR SLIGHT CHANCE AFTERNOON AND EVENING ALONG THE LAST ROW OR TWO
OF COUNTIES SOUTH OF COLUMBUS TO MACON. MOISTURE BEGINS SPREADING
BACK INTO THE FORECAST AREA ON FRIDAY AS LOW LEVEL WINDS TURN TO
THE EAST AND SOUTHEAST. HOWEVER WITH UPPER RIDGE BUILDING OVER THE
SOUTHEAST STATES THROUGH THE END OF THE PERIOD...EXPECTING ONLY
LOW CHANCE OR SLIGHT CHANCE AFTERNOON AND EVENING THUNDERSTORMS
ACROSS THE AREA.

41

&&

.AVIATION...
18Z UPDATE...
SOME MVFR/VFR CEILINGS TO START BUT MAINLY VFR CONDITIONS WITH SCT-BKN
3000-5000 FT CU. BEST CHANCES FOR THUNDERSTORMS LOOK TO BE ACROSS
MAINLY CENTRAL GA THIS AFTERNOON/EARLY EVENING. SURFACE WINDS W-NW
10 KTS OR LESS DIMINISHING WITH SUNSET. PATCHY TO AREAS OF FOG LATE
TONIGHT.

//ATL CONFIDENCE...18Z UPDATE...
LOW-MEDIUM CONFIDENCE FOR MVFR CEILINGS 18-20Z.
MEDIUM CONFIDENCE FOR NO CONVECTION.
HIGH CONFIDENCE ALL OTHER ELEMENTS INTO TONIGHT.

BDL

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          90  68  89  66 /  40  20  10   5
ATLANTA         88  70  89  67 /  30  10   5   5
BLAIRSVILLE     84  61  84  61 /  50  10   5   5
CARTERSVILLE    89  65  88  64 /  20  10   5   5
COLUMBUS        91  72  91  69 /  30  20  20  10
GAINESVILLE     87  68  87  67 /  60  10  10   5
MACON           91  69  92  68 /  30  20  20  10
ROME            88  65  89  63 /  20   5   5   5
PEACHTREE CITY  89  66  88  63 /  30  20   5   5
VIDALIA         90  72  91  71 /  40  20  20  20

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BDL
LONG TERM....17
AVIATION...BDL






AREA FORECAST DISCUSSION

NWS GRAY ME

 1235 PM EDT TUE SEP 3 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FROM WEST TO EAST TODAY...
PROVIDING THE FOCUS FOR THUNDERSTORMS THIS AFTERNOON. THE FRONT
WILL SWEEP OUT ALL THE WET AND HUMID WEATHER BY TONIGHT. A SECOND
COLD FRONT COMES THROUGH WEDNESDAY NIGHT...PROVIDING A BRIEF SHOT
OF MUCH COOLER AIR FOR THE END OF THE WEEK. HIGH PRESSURE WILL
BUILD ACROSS THE REGION LATE THURSDAY THROUGH SATURDAY. ANOTHER
COLD FRONT WILL CROSS NEW ENGLAND SATURDAY NIGHT AND SUNDAY
FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR MONDAY.

&&

.NEAR TERM /TODAY/...
1230PM UPDATE...
COLD FRONT HAS MADE ITS WAY TO PORTSMOUTH BUT NOT QUITE TO
PORTLAND YET. CONVECTION IS LOOKING A LITTLE BIT LESS LIKELY AS A
STRONG CUMULUS FIELD HAS YET TO FORM. HOWEVER... SOME VERTICAL
ENHANCEMENT TO CLOUD TOPS IN NORTHWEST MAINE OVER OXFORD COUNTY
INDICATE THAT SHOWERS ARE LIKELY TO FORM THERE SOON. STILL EXPECT
THE POTENTIAL FOR THUNDERSTORMS TO FORM ALL ALONG THE BOUNDARY
WITH STRONG TO OCCASIONALLY SEVERE THUNDERSTORMS POSSIBLE. HAVE
UPDATED POPS TO REFLECT CURRENT THINKING REGARDING TIMING AND
AREAL COVERAGE OF CONVECTION.

10AM UPDATE...
HAVE UPDATED THE FORECAST TO ADJUST POP AND SKY FORECAST. LOW
CLOUDS OVER MAINE ARE ERODING AND SHIFTING TO THE EAST... ALLOWING
FOR A CLEAR SLOT TO FORM OVER MUCH OF NEW HAMPSHIRE AND NOW INTO
WESTERN MAINE. EXPECT THIS TREND TO CONTINUE WITH MUCH OF THE AREA
BREAKING OUT OF THE CLOUDS OVER THE NEXT FEW HOURS. COLD FRONT IS
PUSHING INTO WESTERN NEW HAMPSHIRE AT THIS TIME... AND WILL BE
LOCATED NEAR THE MAINE BORDER BY EARLY AFTERNOON. THIS SHOULD
PROVIDE THE FOCUS FOR THUNDERSTORMS TODAY. STILL UNCERTAIN HOW
WIDESPREAD STORMS WILL BE... BUT TIMING SHOULD BE AROUND OR
SHORTLY AFTER NOON... SHIFTING EAST THROUGH THE AFTERNOON.
FORECAST SOUNDINGS SHOW CAPE VALUES OF 1000 TO 1500 ACROSS WESTERN
MAINE AHEAD OF THE FRONT THIS AFTERNOON. THIS WILL COMBINE WITH
30 TO 40 KTS OF SHEAR TO CREATE THE POSSIBILITY OF STRONG OR
SEVERE THUNDERSTORMS INCLUDING SUPERCELLS. THE GREATEST THREAT
WILL BE FROM DAMAGING WINDS BUT LARGE HAIL IS ALSO POSSIBLE.

7AM UPDATE...
HAVE UPDATED THE GRIDS TO ADD AREAS OF DRIZZLE ACROSS THE REGION
PER LATEST SURFACE OBSERVATIONS. THIS DRIZZLE AND AREAS OF FOG
WILL SLOWLY BE LIFTING AND MIXING OUT THIS MORNING. STILL EXPECT
SHOWERS AND THUNDERSTORMS TO ERUPT DURING THE MIDDAY PERIOD. A FEW
SHOWERS ASSOCIATED WITH THE FRONT ALREADY IN EASTERN NEW YORK
STATE EARLY THIS MORNING.

REST OF THE FORECAST PACKAGE WILL REMAIN RELATIVELY UNCHANGED.

ORIGINAL DISCUSSION...
LOW CLOUDS AND FOG WILL SLOWLY MIX OUT ACROSS THE REGION THIS
MORNING. EASTERN AREAS...ESPECIALLY NEAR THE COASTLINE...WILL BE
SLOW TO IMPROVE. IN THE MEANTIME...THE LATEST HRRR MODEL RUN
CONTINUES TO SHOW SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING OVER
EASTERN NEW HAMPSHIRE AROUND 17Z. THIS PRECIPITATION IS IN
ASSOCIATION WITH AN APPROACHING COLD FRONT. WITH APPROACHING UPPER
LEVEL TROUGH...WIND MAX AND MODEST INSTABILITY...EXPECT A FEW
STORMS TO CONTAIN DAMAGING WINDS OR HAIL.

HAVE THEREFORE ADDED ENHANCED WORDING TO THE FORECAST PACKAGE.
THUNDERSTORMS WILL CONTINUE UNTIL THIS EVENING...HOWEVER SOME OF
THE CONVECTIVE ACTIVITY WILL HAVE A CHALLENGING TIME MAKING IT
THROUGH ANY REMAINING LOW CLOUDS AND FOG ALONG THE MIDCOAST.

LOOK FOR 70S IN MOST AREAS...HOWEVER SOUTHERN NEW HAMPSHIRE MAY
TIP THE 80 DEGREE MARK.

&&

.SHORT TERM /TONIGHT AND WEDNESDAY/...
THE PRECIPITATION EXITS THE REGION THIS EVENING AS THE COLD FRONT
MOVES EAST. DRIER AIR WILL FILTER INTO THE FORECAST AREA FROM THE
WEST. HOWEVER...PLENTY OF LOW LEVEL MOISTURE FROM RECENT HEAVY
RAINS WILL ALLOW FOR MORE PATCHY FOG TO DEVELOP.

BY WEDNESDAY...THE UPPER LEVEL TROUGH WILL PUSH EAST OF THE
REGION...AND WE WILL BE IN BETWEEN SYSTEMS. A STRONG COLD FRONT
WILL APPROACH FROM THE WEST...BUT MUCH OF THE CLOUDINESS AND ANY
PRECIPITATION WILL HOLD OFF UNTIL AFTER DARK.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN THROUGH THE
FORECAST PERIOD. THE UPPER TROUGH LINGERS ACROSS THE REGION
THROUGH THE UPCOMING WEEKEND BEFORE THE UPSTREAM RIDGE ACROSS THE
INTER-MOUNTAIN WEST FINALLY WEAKENS...AND THE FLOW BECOMES MORE
ZONAL ACROSS THE FORECAST AREA. WE BEGIN THE PERIOD WITH A
RELATIVELY DEEP TROUGH ACROSS THE AREA...AND A SURFACE COLD FRONT
MAKING ITS WAY SOUTHWARD ACROSS THE REGION WEDNESDAY NIGHT AND
EARLY THURSDAY. THIS FRONT WILL USHER BELOW NORMAL TEMPERATURES
INTO THE AREA FOR THURSDAY AND FRIDAY AS HIGH PRESSURE BUILDS
SOUTH AND EAST FROM THE GREAT LAKES. A RETURN FLOW AROUND THE
HIGH WILL INTRODUCE MILDER AIR INTO THE REGION SATURDAY. ANOTHER
SHORTWAVE WILL DRIVE A STRONG COLD FRONT ACROSS THE AREA SATURDAY
NIGHT AND SUNDAY WITH HIGH PRESSURE AND DRY AIR TO FOLLOW FOR
MONDAY.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...AREAS OF LOW CLOUDINESS AND FOG WILL SLOWLY MIX OUT
OVER THE REGION THIS MORNING...WITH THE LAST AREA TO CLEAR BEING EASTERN
AREAS THIS MORNING...ESPECIALLY NEAR THE COASTLINE. HOWEVER...THE
IMPROVEMENT WILL BE BRIEF WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING AFTER NOON TODAY FROM WEST TO EAST. THE LOCALLY STRONG
SHOWERS AND STORMS WILL END THIS EVENING...FOLLOWED BY MORE IFR
AND ISOLATED LIFR CONDITIONS IN DEVELOPING FOG. VFR CONDITIONS ON
WEDNESDAY.

LONG TERM...

WEDNESDAY NIGHT - THURSDAY...SCATTERED MVFR IN SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
SHORT TERM...A COLD FRONT WILL CROSS THE WATERS TODAY WITH
THUNDERSTORMS POSSIBLE. WINDS AND SEAS WILL BE FAIRLY QUIET
OUTSIDE OF THUNDERSTORMS.

LONG TERM...

FRIDAY NIGHT - SATURDAY...WINDS AND SEAS MAY APPROACH SMALL CRAFT
ADVISORY CRITERIA.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$

NEAR TERM UPDATE... KIMBLE







AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY

NWS RAPID CITY SD

 234 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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON
ISSUED AT 234 PM MDT TUE SEP 3 2013

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
AND TONIGHT ACROSS THE AREA. OTHERWISE VFR CONDITIONS WILL CONTINUE
THROUGH THE PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...MLS
LONG TERM...BARBER
AVIATION...BARBER







AREA FORECAST DISCUSSION

NWS SPOKANE WA

 1139 AM PDT Tue Sep 3 2013

.SYNOPSIS...
Showers and thunderstorms will persist over the Inland Northwest
today and Wednesday. Some storms could be severe. A large area of
low pressure will move over the region for the end of the week,
leading to the potential for widespread heavy rain on Thursday and
continuing through Saturday. A drying and warming trend is
expected by the beginning of next week



&&

.DISCUSSION...
Updated the forecast for the rest of today to refine the
thunderstorm threat, touch up the sky cover and adjust our high
temperatures a bit. The leading edge of the shortwave trough of
lower pressure is just now beginning to wrap around into extreme
eastern WA. This wave is anticipated to push across the ID
Panhandle through the early afternoon hours. The main focus of
showers with this wave is across northeastern OR and beginning to
push into the Northeast Blue Mtns, L-C Valley and Camas Prairie.
This is the area where models are showing the best mid level
instability and where the best chances for scattered
thunderstorms will be through the early afternoon ahead of the
disturbance.

Satellite imagery is showing ample amounts of sunshine behind the
disturbance as some drier air loft filters in across the region.
Dew point temperatures will remain in the upper 50s through this
afternoon. Although the NAM looks to be overdoing dew point
temperatures a little bit, I do think we will see the potential
for uncapped surface based CAPEs between 500-1000 J/KG over parts
of the region this afternoon. Best chances for achieving our
convective temperature will be where clouds have cleared out
already and where clouds will clear out by the early afternoon
along the western edge of the shortwave disturbance. Convection
will begin over the higher terrain from the Cascades to the
Northeast Mountains and eventually over the Northeast Blue
Mountains. Surface based convection will be less likely over the
basin, but not out of the question. The HRRR has been consistent
with the best potential for stronger cells to develop over the
Northeast Blue Mountains and then drift northeastward into the L-C
Valley and over onto the southern Palouse. This will be the area
where we may see some stronger thunderstorms and I went ahead and
added heavy rain, gusty winds and small hail in the forecast for
the late afternoon hours.

Temperatures were bumped up a few degrees generally across extreme
eastern WA and into the ID Panhandle as clouds look as if they will
clear out a bit quicker than previously forecast. /SVH


&&

.AVIATION...
18Z TAFS: Scattered showers and thunderstorms are expected mainly
over the higher terrain today. A line of thunderstorms moving out
of northeast OR may impact KLWS through 20Z as a shortwave
disturbances moves across the area. This disturbance is
responsible for the cloud cover expanding across extreme eastern
WA and into the ID Panhandle. Surface based convection is expected
to fire up across the higher terrain this afternoon behind this
band as it shifts eastward. All taf sites (aside from KMWH) will
be at risk of seeing one of these thunderstorms this afternoon,
but best chances will be at KPUW and KLWS. Some storms may become
strong with gusty winds and small hail a possibility. /SVH


&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        84  62  88  64  72  55 /  20  20  50  70  90  80
Coeur d`Alene  83  60  87  61  73  55 /  30  20  60  60  90  90
Pullman        84  59  88  62  70  54 /  60  20  50  60  90  60
Lewiston       88  65  93  68  76  60 /  60  20  50  60  90  70
Colville       88  55  91  59  74  57 /  50  30  60  60 100 100
Sandpoint      82  53  86  59  76  55 /  50  20  50  60 100  90
Kellogg        80  59  85  59  73  53 /  60  40  60  50 100  90
Moses Lake     87  59  89  65  72  57 /  10  10  30  80  90  80
Wenatchee      83  63  85  65  70  58 /  30  20  40  80  90  90
Omak           88  59  87  63  71  58 /  30  20  70  70 100 100

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...&&

$$








AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 239 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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1259 PM CDT TUE SEP 3 2013

MAIN FORECAST CONCERNS ARE ON VALLEY FOG POTENTIAL AT KLSE. VFR
CONDITIONS ARE EXPECTED AT KRST THROUGH THE FORECAST PERIOD. HIGH
PRESSURE WILL SLIDE SOUTHEAST OF THE REGION TONIGHT AS A WEAK COLD
FRONT SLIDES SOUTH OUT OF NORTH DAKOTA/NORTHERN MINNESOTA. CIRRUS
STREAMING ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THIS AFTERNOON
AND EVENING SHOULD GRADUALLY THIN AND PUSH SOUTH OF THE AREA
GIVING WAY TO MOSTLY CLEAR SKIES. THIS WILL SET THE STAGE FOR
PATCHY VALLEY FOG ALONG THE MISSISSIPPI RIVER VALLEY IMPACTING
KLSE. WINDS JUST ABOVE THE SURFACE THROUGH 1200 FT INCREASE INTO
THE 10 TO 14 KT RANGE WHICH SHOULD INHIBIT DENSE FOG FORMATION AT
KLSE AS THE FRONTAL BOUNDARY SLIPS SOUTH INTO THE AREA. CONDITIONS
LOOK FAVORABLE FOR VALLEY FOG EARLY TONIGHT BUT THEN BECOME LESS
FAVORABLE LATE TONIGHT INTO EARLY WEDNESDAY MORNING AS THE WINDS
ALOFT INCREASE. THINKING PATCHY FOG AND VALLEY STRATUS WILL BE THE
MOST LIKELY OUTCOME AT KLSE TONIGHT. WILL HAVE TO MONITOR WINDS AT
BLUFF TOP TONIGHT VERY CLOSELY. IF THE GRADIENT DOESN/T INCREASE
AS FORECAST...DENSE FOG WOULD RESULT.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP