Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/02/12

AREA FORECAST DISCUSSION

NWS ALBANY NY

826 PM EDT SAT SEP 1 2012

.SYNOPSIS...
HIGH PRESSURE WILL MOVE EAST FROM THE UPPER GREAT LAKES
TODAY...TO JUST NORTH OF NEW YORK BY SUNDAY EVENING...BRINGING MAINLY
FAIR WEATHER. THE REMNANTS OF ISAAC WILL APPROACH THE REGION ON
LABOR DAY...BRINGING AN INCREASE IN CLOUDINESS AND A THREAT OF
SHOWERS MONDAY NIGHT AND TUESDAY.

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 8 PM EDT...SKIES REMAIN CLEAR TO PARTLY CLOUDY...WITH THE
MOST CONCENTRATED CLOUD PATCHES ACROSS THE IMMEDIATE CAPITAL
REGION...AS WELL AS ACRSS THE SOUTHERN GREENS INTO THE BERKSHIRES
AND LITCHFIELD HILLS. THERE IS YET ANOTHER BOUNDARY...WHICH SEEMS
TO BE A HYBIRD SEABREEZE/SIDE DOOR FRONT...CURRENTLY ADVANCING WEST
NORTHWEST INTO NW CT AND THE BERKSHIRES. CLOUDS...AND EVEN
ISOLATED SHOWERS HAVE DEVELOPED NEAR OR JUST BEHIND THIS BOUNDARY
ACROSS NORTHERN CT AND SOUTH CENTRAL MA OVER THE PAST 2 HOURS. IT
IS POSSIBLE THAT...AS THIS BOUNDARY MOVES FURTHER N AND
W...ADDITIONAL ISOLATED SHOWERS COULD DEVELOP ACROSS HIGHER
ELEVATIONS OF WESTERN NEW ENGLAND. WILL THEREFORE KEEP SLIGHT CHC
POPS IN THIS REGION...AS WELL AS ACROSS PORTIONS OF THE SE
CATSKILLS WHERE A LIGHT UPSLOPE FLOW MAY ALSO ALLOW A SHOWER OR
TWO TO DEVELOP.

WE WILL HAVE TO WATCH HOW FAR N/W THIS BOUNDARY REACHES. THE
LATEST HRRR SUGGESTS IT REACHES THE WEST SIDE OF THE HUDSON RIVER
VALLEY LATER TONIGHT. THIS MAY ALLOW FOR MORE CLOUDS TO PERSIST
OVERNIGHT...AND MAY ALSO KEEP TEMPS FROM FALLING MUCH BELOW THE
LOWER 60S IN THE HUDSON RIVER VALLEY. WILL MONITOR TRENDS THROUGH
THE EVENING FOR POSSIBLE AMENDMENTS TO ONGOING FORECAST.

FURTHER N AND W...WITH DRY AIR...LIGHT WINDS AND MOSTLY CLEAR
SKIES...TEMPERATURES SHOULD RADIATE DOWN TO COOL COMFORTABLE
TEMPERATURES IN THE 40S AND 50S F BY MORNING.

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
HIGH PRESSURE SHOULD BRING FAIR WEATHER TO MOST OF THE AREA
SUNDAY. AN UPPER LEVEL SHORT WAVE MOVING ACROSS NEW ENGLAND MAY
BRING SOME CLOUDS AND AN ISOLATED SHOWER TO OUR NEW ENGLAND
COUNTIES. MOISTURE IS LIMITED BUT THERE IS A 100KT JET STEAK
FORECAST TO ROUND THE BASE OF THE SHORTWAVE TOMORROW AFTERNOON SO
IMPRESSIVE DYNAMICS. BEST CHANCE FOR SHOWERS LOOKS TO BE NORTHEAST
OF OUR FORECAST AREA.

ON LABOR DAY...THE REMNANTS OF ISAAC START TO GET
CLOSER...REACHING THE OHIO VALLEY. MODELS HAVE SLOWED THE
NORTHEASTWARD PROPAGATION OF THE STORM AND ITS MOISTURE SO MOST OF
LABOR DAY LOOKS DRY. CLOUDS SHOULD INCREASE...ESPECIALLY LATE IN
THE DAY...BUT PRECIPITATION LOOKS LIKE IT WONT MOVE INTO OUR AREA
UNTIL MONDAY NIGHT.

.LONG TERM /TUESDAY THROUGH SATURDAY/...
HAVE GENERALLY UTILIZED A 50/50 BLEND OF 18Z/01 HPCMOS AND 12Z/01
GMOS FOR THIS PORTION OF THE GRIDDED DATABASE.

TUE-WED...CONFIDENCE REMAINS FAIRLY HIGH FOR SHOWERS...OR A PERIOD
OF STEADY RAIN ALONG WITH EMBEDDED DOWNPOURS/ISOLATED THUNDER WILL
OCCUR DURING THIS TIME PERIOD...AS THE REMNANTS FROM TC ISSAC DRIFT
INTO THE REGION...AHEAD OF AN APPROACHING SHORTWAVE FROM THE GREAT
LAKES. PWAT/S INCREASE INTO THE 1.75-2 INCH RANGE...OR EVEN A BIT
HIGHER...WHICH IS AT LEAST +2 TO +3 SD. THIS CERTAINLY SUGGESTS THAT
LOCALLY HEAVY RAIN WILL BE POSSIBLE...ESP TUE INTO TUE NT. THERE IS
SOME UNCERTAINTY AS TO HOW QUICKLY THE DEEPEST MOISTURE MOVES EAST
OF THE REGION...WITH THE 12Z/01 GFS AND GEFS SUGGESTING BY WED
AM...WHILE THE 12Z/01 ECMWF IS A BIT SLOWER...SUGGESTING LATE WED OR
WED NT. HAVE INCLUDED LIKELY POPS FOR TUE-TUE NT...TAPERING INTO THE
40-50 PERCENT RANGE FOR WED...HIGHEST ACROSS NE AREAS. IT IS
POSSIBLE THAT A STEADIER RAIN OCCURS FOR TUE/TUE NT...THEN A MORE
SHOWERY REGIME DEVELOPS FOR WED. IT WILL BE QUITE HUMID DURING THIS
PERIOD...WITH DEWPOINTS INCREASING TO 65-70 IN MOST AREAS. DAYTIME
MAXES MAY BE HELD DOWN A BIT DUE TO ABUNDANT CLOUDS AND
SHOWERS...WITH MAINLY 75-80 INDICATED FOR TUE MAXES...AND PERHAPS A
BIT WARMER...UPPER 70S TO LOWER 80S IN VALLEYS AND MID 70S FOR
HIGHER ELEVATIONS ON WED. EVEN WARMER MAXES ARE POSSIBLE WED SHOULD
MORE BREAKS IN THE CLOUDS DEVELOP. TUE NT/WED AM SHOULD BE QUITE
WARM/HUMID...WITH MINS ONLY FALLING INTO THE 60S IN MOST AREAS.

WED NT-THU NT...LONG TERM MODELS SUGGEST ANOTHER FAIRLY STRONG
SHORTWAVE APPROACHES FROM THE GREAT LAKES...MOST LIKELY LATE THU OR
THU NT...PRECEDED BY A SFC COLD FRONT. WILL THEREFORE KEEP CHC POPS
FOR MUCH OF THIS PERIOD FOR SHOWERS AND ISOLATED TSTMS. TEMPS SHOULD
REMAIN ABOVE SEASONAL LEVELS...WITH MAXES REACHING THE LOWER/MID 8OS
IN VALLEYS...AND 75-80 ACROSS HIGHER TERRAIN...WITH OVERNIGHT MINS
MAINLY IN THE LOWER/MID 60S IN VALLEYS...AND 55-60 ACROSS HIGHER
ELEVATIONS.

FRI-SAT...LONG TERM MODELS INDICATE COOLER...LESS HUMID CONDITIONS
FILTER INTO THE REGION BEHIND AFOREMENTIONED COLD FRONTAL PASSAGE.
THERE IS SOME POSSIBILITY THAT LAKE EFFECT AND/OR UPSLOPE
CLOUDS...AND PERHAPS A FEW SHOWERS OCCUR ACROSS PORTIONS OF THE
SOUTHERN ADIRONDACKS...AND SOUTHERN GREEN MOUNTAINS FRI...WHERE
SLIGHT CHC POPS ARE INDICATED. ELSEWHERE...HAVE INDICATED RAIN FREE
CONDITIONS. EXPECT MORE SEASONABLE TEMPS...WITH MAXES MAINLY
REACHING 75-80 IN VALLEYS...AND 65-70 ACROSS HIGHER ELEVATIONS.
OVERNIGHT MINS SHOULD FALL INTO THE LOWER/MID 50S IN VALLEYS...WITH
40S ACROSS THE SOUTHERN ADIRONDACKS...AND POSSIBLY HIGHER ELEVATIONS
ACROSS WESTERN NEW ENGLAND.

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING. THEN...AS LOW
LEVEL MOISTURE INCREASES IN THE WAKE OF A WEAK BOUNDARY MOVING
WESTWARD FROM NEW ENGLAND...THERE IS A SLIGHT CHC THAT SOME MVFR
OR EVEN IFR VSBYS COULD DEVELOP AFTER 08Z/SUN AT KPSF...AND
POSSIBLY KGFL...IN ADDITION TO MVFR CIGS. AT THIS
TIME...CONFIDENCE TOO LOW TO INCLUDE IFR CONDITIONS...BUT HAVE
INDICATED MVFR VSBYS LATER TONIGHT AT KPSF. ALSO...ISOLATED
SHOWERS COULD AFFECT KPSF THROUGH MIDNIGHT AS THIS BOUNDARY PASSES.

ON SUNDAY...EXPECT MAINLY VFR LEVEL CU/STRATO-CU.

LIGHT/VARIABLE WINDS WILL BECOME SE OVERNIGHT AT LESS THAN 5 KT.
ON SUNDAY...EXPECT LIGHT SOUTH TO SOUTHWEST WINDS AT MOST TAF
SITES AT LESS THAN 8 KT...WITH WINDS BECOMING N TO NE IN THE AFTERNOON.

OUTLOOK...
SUN PM...VFR. SLIGHT CHC -SHRA NEAR KPOU.
MON...VFR. NO SIG WX.
TUE...MVFR/IFR. CHC SHRA.
WED...VFR/MVFR. CHC -SHRA.
THUR..VFR. NO SIG WX.

.FIRE WEATHER...
HIGH PRESSURE WILL BRING MAINLY DRY CONDITIONS THROUGH LABOR DAY.
RELATIVE HUMIDITY BOTH TONIGHT AND TOMORROW NIGHT SHOULD BE 80
PERCENT TO 100 PERCENT. RELATIVE HUMIDITY ON SUNDAY AFTERNOON WILL
LOWER TO 35 TO 60 PERCENT. WINDS WILL BECOME LIGHT AND VARIABLE
TONIGHT AND REMAIN LIGHT AND VARIABLE ON SUNDAY AND SUNDAY NIGHT.
ON LABOR DAY...SOUTHEAST WINDS OF 10 TO 20 MPH ARE EXPECTED.

.HYDROLOGY...
MAINLY DRY WEATHER IS EXPECTED THROUGH LABOR DAY. THE REMNANTS OF
ISAAC WILL INTERACT WITH A FRONT AND BRING RAIN TO OUR AREA BY
TUESDAY. LATEST MODEL GUIDANCE SUGGESTS A WIDESPREAD 1 TO 2 INCHES
OF RAIN WITH LOCALLY HIGHER AMOUNTS. NO RIVER FLOODING IS FORECAST
AT THIS TIME.

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

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

AREA FORECAST DISCUSSION

NWS MELBOURNE FL

337 AM EDT FRI AUG 31 2012

.DISCUSSION...

...RIP CURRENT THREAT INCREASING OVER THE HOLIDAY WEEKEND...

TODAY/TONIGHT...
TWO DISTINCT H100-H70 ANTICYCLONIC GYRES...ONE OVER THE CAROLINAS
AND ONE JUST E OF THE NRN BAHAMAS...WILL MERGE OVER THE SERN
SEABOARD TODAY AND GENERATE A DEEP N/NERLY FLOW ACRS THE FL
PENINSULA. NE FLOW REGIMES TYPICALLY ARE QUITE STABLE FOR CENTRAL FL
AS THEY TEND TO PUSH DRY/STABLE CONTINENTAL AIR INTO THE REGION.

THE 00Z SOUNDINGS CONTINUE TO SHOW PLENTIFUL MOISTURE ACRS THE STATE
WITH PWAT VALUES BTWN 1.8"-2.0". HOWEVER...THE KTBW/KMFL/KEYW
SOUNDINGS ALL SHOW THE MOISTURE IS MORE OR LESS EVENLY DISTRIBUTED
THRU THE COLUMN...NOT CONCENTRATED IN THE LOW/MID LVLS IN A MANNER
THAT WOULD SUPPORT PRECIP. LATEST RAP ANALYSIS ALSO SHOWS UPSTREAM
MEAN RH VALUES THRU THE H100-H70 LYR ARE LARGELY AOB 70PCT.
FURTHERMORE...RAP ANALYSIS SHOWS H70 TEMPS ARND 10C...H50 TEMPS
AROUND -5.5C...RESULTING IN MID LVL LAPSE RATES AOB 5.5C/KM.

ALOFT...A THIN BAND OF WEAK H85-H50 VORTICITY IS NOTED OVER THE NECK
OF THE PENINSULA BUT IS EMBEDDED IN VERY WEAK FLOW...WHILE THE
H30-H20 WIND PATTERN IS WEAKLY CONVERGENT. SAT PICS SHOW UPR LVL
CLOUD DECK IS NOT AS ROBUST AS A FEW HRS AGO...BUT ANY UPR LVL
DEBRIS CLOUDS THAT PUSH INTO CENTRAL FL WOULD ONLY FURTHER "DAMPEN"
PRECIP CHANCES.

THE AIRMASS IS CONDITIONALLY UNSTABLE...BUT JUST BARELY. WITH
H100-H70 DRY AIR ADVECTION TAKING PLACE...MID LVL THERMAL RIDGING...
AND WEAK DYNAMIC SUPPORT...STORM COVERAGE TODAY WILL BE PRIMARILY
DEPENDENT ON MESOSCALE BOUNDARY COLLISIONS TO FORCE VERTICAL MOTION.
HOWEVER...WITH A NE FLOW REGIME IN PLACE...MOST OF THESE WILL OCCUR
OVER THE W PENINSULA. WILL MENTION A SLGT CHC OF TSRAS OVER THE
INTERIOR COUNTIES AS THINNING UPR LVL CLOUDS MAY ALLOW A FEW SPOTS
TO REACH THEIR CONVECTIVE TEMPS...BUT EVEN THIS IS GENEROUS GIVEN
THE TORPID NATURE OF THIS AIRMASS. THE DEEPENING ONSHORE FLOW WILL
KEEP MAX TEMPS NEAR AVG (U80S/L90S)...MIN TEMPS ABV AVG (M70S).

HOLIDAY WEEKEND...
RIDGING ALOFT AND NORTHEAST UPPER LEVEL WINDS ARE INDICATED ALONG WITH
DEEP LAYER DRYING SO HAVE GONE WITH A DRY FORECAST...ESPECIALLY
SINCE MOS POPS ARE 10 PERCENT OR LESS. AT THE SURFACE...HIGH
PRESSURE RIDGE TO OUR NORTH WILL PROVIDE AN ONSHORE FLOW. THIS
WILL KEEP COASTAL HIGH TEMPS IN THE UPPER 80S WITH MAINLY LOWER
90S ACROSS THE INTERIOR.

WILL HAVE TO WATCH FOR A SMALL LONG PERIOD SWELL FROM DISTANT
TROPICAL CYCLONE KIRK AFFECTING THE BEACHES AND LEADING TO
DANGEROUS RIP CURRENTS BY SUNDAY. SWELLS FROM LESLIE MAY ARRIVE AS
EARLY AS MON.

TUE-FRI...MID-UPPER LEVEL LOW IS FORECAST TO PUSH SLOWLY WEST
ACROSS THE NORTHERN BAHAMAS THEN LIFT OUT TO THE NORTH AS NORTHERN
STREAM TROUGH DIGS OVER THE EASTERN HALF OF THE COUNTRY. THIS RUN
HAS THE LOW MOVING CLOSER TO THE AREA AND THE SUBSIDENCE OUT AHEAD
OF IT PERSISTING LONGER. MOS POPS ONLY REACH 20 PERCENT ON
TUE...30 PERCENT WED-THU...40 PERCENT FRI AND WILL LARGELY FOLLOW
THESE NUMBERS. AT THE SURFACE...THE FLOW REGIME WILL GRADUALLY
TRANSITION FROM LIGHT ONSHORE TO LIGHT OFFSHORE BY LATE WEEK. VERY
LITTLE CHANCE IN HIGH TEMPS INDICATE.

LONG PERIOD SWELLS FROM DISTANT TROPICAL CYCLONE LESLIE WILL CONTINUE
THE THREAT FROM DANGEROUS RIP CURRENTS THROUGH AT LEAST MID WEEK.

.AVIATION...
THRU 31/12Z...LCL MVFR CIGS/VSBYS IN BR N OF KGIF-KDAB...OTHERWISE
VFR ALL SITES THRU 01/00Z...CIGS AOA FL120.

.MARINE...
TODAY/TONIGHT...BROAD SFC/LOW LVL RIDGE CENTERED OVER THE SE COAST
WILL GENERATE A LIGHT TO GENTLE ERLY BREEZE ACRS THE LCL ATLC. SEAS
AOB 2FT. NO TSTM ACTIVITY ANTICIPATED AS NERLY FLOW ALOFT WILL FOCUS
WHAT FEW STORMS FORM THAT DO FORM OVER W FL.

WEEKEND...HIGH PRESSURE RIDGE TO OUR NORTH WILL PROVIDE A
NORTHEAST TO EAST WIND FLOW. THE GFS SHOWS A WEAK INVERTED TROUGH
TRANSITING THE COASTAL WATERS SAT NIGHT INTO SUN WITH POSSIBLE
10-15 KNOTS FLOW...BUT OTHERWISE SPEEDS SHOULD BE AROUND 10 KNOTS.
THE INVERTED TROUGH MAY BRING A FEW SHOWERS...BUT HAVE NOT
INCLUDED IN THE FORECAST YET. SWELLS FROM DISTANT TROPICAL CYCLONE
KIRK MAY IMPACT THE WATERS BY SUNDAY.

MON-TUE...THE HIGH PRESSURE RIDGE WILL SLOWLY PUSH OFFSHORE WITH
MAINLY EAST WINDS 10 KNOTS OR LESS. SMALL FORERUNNER SWELLS FROM
DISTANT TROPICAL CYCLONE LESLIE WILL ARRIVE LATE MON AND CONTINUE
THROUGH MID WEEK WITH GRADUALLY INCREASING HEIGHTS. NAVIGATION
THROUGH INLETS DURING THE OUTGOING TIDE WILL BECOME HAZARDOUS.

.PRELIMINARY POINT TEMPS/POPS...
DAB 88 74 89 71 / 10 0 10 10
MCO 92 75 92 72 / 20 0 10 10
MLB 89 77 87 75 / 10 0 10 10
VRB 88 76 88 73 / 10 0 10 10
LEE 92 74 93 72 / 20 0 10 10
SFB 93 75 91 72 / 20 0 10 10
ORL 92 75 92 73 / 20 0 10 10
FPR 88 76 88 73 / 10 10 10 10

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&

SHORT TERM/AVIATION...BRAGAW
LONG TERM....LASCODY

AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

513 PM CDT FRI AUG 31 2012

.DISCUSSION...
349 PM CDT

MAIN FORECAST CONCERNS THIS FORECAST PERIOD REVOLVE AROUND PRECIP
CHANCES AND TRENDS...POSSIBLE HEAVY AT TIMES...THIS WEEKEND INTO
THE START OF NEXT WEEK AS REMNANTS OF TROPICAL STORM ISAAC WORK
ITS WAY NORTH ACROSS THE REGION.

IN THE NEAR TERM...LATEST SATELLITE IMAGERY DEPICTING EXPANSIVE
AREA OF MID AND HIGH LEVEL CLOUD COVER CONTINUING TO SPREAD
NORTHWARD ACROSS MUCH OF THE REGION AS THIS SYSTEM SLOWLY MOVES
NORTH. DESPITE AN INCREASE IN CLOUD COVER TODAY...MOSTLY SUNNY TO
PARTLY CLOUDY SKIES HAVE BEEN OBSERVED WITH TEMPERATURES RISING TO
THE LOWER 90S ACROSS NORTHERN ILLINOIS AND MID TO UPPER 80S ACROSS
AREAS SOUTH OF INTERSTATE 80. DESPITE LATEST RADAR IMAGERY SHOWING
SOME WEAK RETURNS FROM THE OUTER BANDS OF THIS SYSTEM ACROSS AREAS
FROM PONTIAC IN ILLINOIS EAST TO FOWLER IN INDIANA...MOST OF THIS
IS NOT REACHING THE GROUND. SOME DRIER AIR IS HELPING WITH THIS
BUT WITH A VERY MOIST AIRMASS ON ITS WAY...IT SHOULDNT TAKE MUCH
LONGER THIS EVENING BEFORE IT STARTS REACHING THE GROUND. OUTSIDE
OF THIS SYSTEM TO THE SOUTH...A COLD FRONT HAS BEEN DROPPING SOUTH
THROUGH PORTIONS OF WISCONSIN TODAY. ALTHOUGH...EXPECT THIS FRONT
TO LOSE ITS SOUTHWARD MOMENTUM THIS EVENING AND THEN BECOME MORE
DIFFUSE AS THE SYSTEM TO THE SOUTH MOVES INTO THE AREA. DESPITE
THIS FRONT ACROSS THE REGION...ANY VERTICAL DEVELOPMENT HAS BEEN
LIMITED AND IS EXPECTED TO REMAIN THIS WAY AS A MORE SUBSIDENT
LARGE SCALE ENVIRONMENT REMAINS OVER THIS BOUNDARY.

SHIFTING TOWARD MAIN FOCUS OF THIS FORECAST PERIOD...REMNANTS OF
TROPICAL STORM ISAAC CONTINUE TO SLOWLY SHIFT NORTH THROUGH
MISSOURI THIS AFTERNOON. THIS SYSTEM IS MARKED WITH A VERY MOIST
ENVIRONMENT...OR A TROPICAL ENVIRONMENT. COPIOUS AMOUNTS OF
MOISTURE WITH 12Z SOUNDINGS ACROSS MISSOURI INDICATING PWATS
AROUND 2.4 INCHES THIS MORNING...AND LATEST RUC ANALYSIS SHOWING
THIS AXIS OF HIGHER PWATS EXTENDING FROM THE ST. LOUIS AREA BACK
SOUTH THROUGH MISSOURI INTO ARKANSAS. WITH A SLOW MOVEMENT OF THIS
SYSTEM TONIGHT...THIS AXIS OF HIGHEST MOISTURE WILL ALSO SHIFT
SLOWLY. NONETHELESS...THESE OUTWARD BANDS OF THIS SYSTEM AND
HIGHER MOISTURE CONTENT AIR WILL LIFT NORTH OVERNIGHT. THIS SHOULD
HELP BRING SHOWERS ACROSS THE SOUTHERN CWA PRIMARILY FOR AREAS
ALONG AND SOUTH OF A LINE FROM PONTIAC IN ILLINOIS TO RENSSELAER
IN INDIANA. HEAVIER DOWNPOURS ARE NOT EXPECTED TONIGHT AS WELL AS
ANY THUNDER. DESPITE SOME INSTABILITY IN PLACE...THESE INITIAL
SHOWERS WILL BE WEAKLY FORCED. ITS NOT UNTIL SATURDAY THROUGH THE
REMAINDER OF THE WEEKEND THAT THE MAIN AXIS OF HIGHEST MOISTURE
AND RAINFALL WILL REACH THE CWA. WITH BETTER FORCING WITH THIS
SYSTEM SHIFTING NORTH AND SREF GUIDANCE INDICATING THAT THE AXIS
OF HIGHER PWATS/MUCH HIGHER DEWPOINT AIR WILL REACH THE SOUTHERN
CWA...THE POTENTIAL FOR HEAVIER RAIN WILL INCREASE. DESPITE SOME
MODEL VARIABILITY WITH THE OVERALL EVOLUTION OF THIS
SYSTEM...CONFIDENCE IS HIGH FOR AREAS ALONG AND SOUTH OF
INTERSTATE 80 TO RECEIVE THE HIGHEST AMOUNTS OF RAIN THIS WEEKEND.
WHERE CONFIDENCE IS LOWER AT THIS TIME IS IN REGARDS TO HOW FAR
NORTH THIS RAIN WILL WORK ITS WAY NORTH. AS A FAIRLY TIGHT
GRADIENT IS EXPECTED WITH THIS PRECIP SHIELD THIS WEEKEND...HAVE
TRIED TO CONVEY THIS AS BEST AS POSSIBLE IN THE GRIDS. IF THIS
SYSTEM WERE TO SHIFT NORTHWARD THAN PREVIOUSLY THOUGHT...THEN THIS
AXIS OF RAINFALL WOULD OF COURSE SHIFT NORTH ACROSS THE CWA. AT
THIS POINT IT APPEARS THAT A DRASTIC CUTOFF IN PRECIP SHOULD OCCUR
AROUND THE I88 CORRIDOR. IN ALL AREAS ACROSS OUR CWA ARE EXPECTED
TO RECEIVE A LARGE AMOUNT OF RAINFALL THROUGH SUNDAY NIGHT...WITH
THE POTENTIAL FOR AMOUNTS OF 4 TO 5 INCHES OR GREATER ALONG AND
SOUTH OF A LINE FROM THE PONTIAC AREA TO THE RENSSELAER AREA.
MOVING NORTH OF THIS LINE...RAINFALL AMOUNTS ARE EXPECTED TO TAPER
FROM AROUND 3 TO 4 INCHES TO AROUND 1 INCH JUST NORTH OF THE
INTERSTATE 80 CORRIDOR. EXPECTED AMOUNTS ALONG THE INTERSTATE 88
CORRIDOR WILL ROUGHLY RANGE FROM THREE QUARTERS OF AN INCH UP TO
ONE INCH...WITH THE POTENTIAL FOR LITTLE OR NO RAIN IN THE
COUNTIES BORDERING WISCONSIN...GENERALLY UNDER A QUARTER INCH. NO
HEADLINES AT THIS TIME BUT WILL CONTINUE THE ESF TODAY.

RODRIGUEZ

.HYDROLOGY...
427 PM CDT

EXPECTED RAINFALL AND POTENTIAL FOR HEAVY RAINFALL...POTENTIALLY
FOR PERIODS OF TIME...ACROSS PORTIONS OF THE CWA STILL ON TRACK
LATE TONIGHT THROUGH THE END OF THE WEEKEND. LATEST OBSERVATIONAL
DATA STILL INDICATING A GOOD SWATH OF MOISTURE JUST SOUTH OF THE
CWA THIS AFTERNOON...WITH LATEST GUIDANCE INDICATING THIS HIGHER
MOISTURE CONTENT AIR TO CONTINUE SPREADING NORTHWARD TONIGHT INTO
SATURDAY. AS THIS SLUG OF MOISTURE MOVES ACROSS THE CWA EARLY
SATURDAY...IT WILL THEN LINGERING THROUGH THE REMAINDER OF THE
WEEKEND. ALTHOUGH...LATEST GUIDANCE CONTINUES TO INDICATE THAT THE
HIGHEST RAIN RATES/RAINFALL SHOULD STAY ACROSS THE SOUTHERN CWA
WHICH SEEMS TO BE ON TRACK. THE POTENTIAL FOR RAINFALL AMOUNTS OF
4 TO 5 INCHES OR GREATER ALONG AND SOUTH OF A LINE FROM THE
PONTIAC AREA TO THE RENSSELAER AREA SEEM TO BE ON TRACK FOR THIS
WEEKEND. MOVING NORTH OF THIS LINE...RAINFALL AMOUNTS ARE EXPECTED
TO TAPER FROM AROUND 3 TO 4 INCHES TO AROUND 1 INCH JUST NORTH OF
THE INTERSTATE 80 CORRIDOR. EXPECTED AMOUNTS ALONG THE INTERSTATE
88 CORRIDOR WILL ROUGHLY RANGE FROM THREE QUARTERS OF AN INCH UP
TO ONE INCH...WITH THE POTENTIAL FOR LITTLE OR NO RAIN IN THE
COUNTIES BORDERING WISCONSIN...GENERALLY UNDER A QUARTER INCH.
DESPITE THE EXPECTED HIGHER RAINFALL THIS WEEKEND...ONLY MINOR
RISES IN AREAS RIVERS ARE EXPECTED WITH NO MAJOR PROBLEMS EXPECTED
AT THIS TIME. A WORST CASE SCENARIO AT THIS TIME BASED ON CURRENT
FORECASTS WOULD BE FOR RIVERS THAT RECEIVE THESE HIGHER AMOUNTS TO
RISE TO MINOR OR JUST ABOVE MODERATE STAGES. ALTHOUGH WOULD LIKE
TO REITERATE SOME UNCERTAINTY WITH THIS SYSTEMS OVERALL
EVOLUTION...THAT EXTENDS INTO THE POTENTIAL RISES. WITH THIS IN
MIND...THIS SITUATION NEEDS TO CONTINUE TO BE CLOSELY MONITORED
THIS WEEKEND AS IT WOULD NOT BE OUT OF THE QUESTION FOR LOCALIZED
AREAS OF HIGHER AMOUNTS AND THUS POSSIBLE HIGHER RISES. SOMETHING
ELSE TO KEEP IN MIND THIS WEEKEND IS THE OVERALL SOIL CONDITIONS
ACROSS THE AREA. WITH A DRY/HARD SOIL IN PLACE...IT WOULD NOT TAKE
MUCH TIME FOR HIGH RAINFALL RATES TO QUICKLY TURN INTO RUNOFF.
ONCE AGAIN...HAVE NOT ISSUED ANY FLOOD HEADLINES AT THIS TIME.
ALTHOUGH...CONTINUE TO MONITOR LATEST UPDATES THIS WEEKEND AS THIS
COMPLEX SYSTEM UNFOLDS ACROSS THE REGION.

RODRIGUEZ

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* TIMING WIND SHIFT FROM SW TO NE AS FRONTAL BOUNDARY SAGS SOUTH
ACROSS THE TERMINALS.

* TIMING ONSET OF RAINFALL SAT.

BEACHLER

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

MODERATE SW-WSW LOW LEVEL FLOW HAS BEEN MIXING DOWN TO THE
SURFACE WITH THE SKC CONDITIONS ALLOWING MAXIMUM HEATING THROUGH
MIDDAY RESULTING IN SOME GUSTS IN THE 15-20KT RANGE THIS MORNING.
OUTER EDGE OF CLOUD SHIELD OF THE T.D. CENTERED OVER SW MO HAVE
SPREAD TO THE WI BORDER BY EARLY AFTERNOON WITH THICKER CIRRUS
STRATUS TO SPREAD ACROSS THE LOCAL AREA DURING THE MID TO LATE
AFTERNOON.

WITH THICKENING HIGH CLOUDS ADDITIONAL INSOLATION WILL BE
DECREASING THIS AFTERNOON...AND AS THE COLD FRONT ACROSS SOUTHERN
WI CONTINUES TO CREEP SOUTHWARD THE SURFACE PRESSURE GRADIENT
SLACKENS DURING THE AFTERNOON. WITH DECREASE IN BOTH SURFACE
HEATING AND IN SURFACE PRESSURE GRADIENT SW-WSW WINDS WILL LOSE
ANY MARGINAL GUSTS AND SETTLE TO SUSTAINED 10-12KT TIL DUSK. THE
COLD FRONT IS SHOWN BY MODELS TO CROSS INTO FAR NORTHERN IL LATE
THIS AFTERNOON AND EARLY THIS EVENING RESULTING IN A WIND SHIFT
TO OUT OF THE NE-E AT 6-10KT.

MODELS OFFERING SIMILAR SOLUTIONS ON LARGE SCALE BUT DIFFERENCES
IN TIMING AND TRACK OF THE LOW OUT OF CENTRAL MO TO TO W CENTRAL
IL SAT AND SAT NIGHT STILL LEAVES QUESTIONS ABOUT HOW FAR N THE
RAIN WILL SPREAD AND HOW SOON IT WILL ARRIVE IN THE LOCAL AREA.
TREND OF MODELS HAS BEEN SLOWER AND A BIT FURTHER S OF PREVIOUS
FORECAST TRACKS. THIS DELAYS ARRIVAL OF ONSET OF RA AND KEEPS
HEAVIER RAIN S OF ORD AND MDW.

LOWER DEW POINT AIR BEHIND THE SLUGGISH COLD FRONT WILL BE
ADVECTED OVER THE LOCAL TERMINALS ON NE-E LOW LEVEL WINDS
BECOMING MODERATE TONIGHT BETWEEN HIGH PRESSURE BUILDING INTO THE
UPPER GREAT LAKES AND THE LOW RIDGE BETWEEN THE MO LOW. SLIGHTLY
MORE SOUTHWARD TRACK OF THE LOW AS IT MOVES INTO CENTRAL IL SUN
AND INFLUX OF LOWER LOW LEVEL POINTS IS EXPECTED TO DELAY AND
SIGNIFICANT THREAT OF SHRA/RA TIL LATER MORNING-EARLY AFTERNOON
ON SAT...THEN PERSISTING THROUGH THE DAY. WITH HEAVER RAIN
OCCURRING TO THE S OF THE TERMINALS AND THE FEED LOW DRIER LOW
LEVEL AIR EXPECT VFR CONDITIONS TO PREVAIL LOCALLY THOUGH MAY BE
AREAS MVFR BY MID-LATE SAT AFTERNOON.

TRS

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH CONFIDENCE IN WIND SPEED.

* MEDIUM/HIGH CONFIDENCE IN WIND SHIFT FROM SW TO NE.

* MODERATE CONFIDENCE IN TIMING OF THE COLD FRONT PASSAGE THIS
EVENING AND THE ACCOMPANYING WIND SHIFT.

* HIGH CONFIDENCE IN VFR AND DRY CONDITIONS THROUGH THE NIGHT AND
EARLY SAT MORNING.

* MODERATE CONFIDENCE IN PREVAILING VFR CONTINUING FROM MID SAT
MORNING ON WITH ONLY AREAS/OCCASIONAL MVFR.

BEACHLER

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

SATURDAY NIGHT...

SUNDAY...CHC OF RA/SHRA. MVFR/IFR POSSIBLE.

MONDAY...SLGT CHC SHRA/TSRA. MVFR POSSIBLE.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...CHC SHRA/TSRA. OTHERWISE VFR.

RATZER

.MARINE...
351 PM CDT

A COLD FRONT IS SLOWLY SINKING SOUTH ALONG LAKE MICHIGAN AND IS
CURRENTLY LOCATED FROM THE WI/IL STATE LINE THROUGH MUSKEGON. THE
FRONT WILL REACH SOUTHERN LAKE MICHIGAN THIS EVENING WITH WINDS
TURNING NORTH TO NORTHEAST AND GUSTING TO AROUND 20 KT. WINDS WILL
DIMINISH TO 10 TO 15 KT BEHIND THE FRONT AND VEER TO THE EAST BY
SATURDAY MORNING OVER THE SOUTHERN HALF OF THE LAKE. WINDS WILL BE
EAST ALONG THE ENTIRE LAKE BY SATURDAY NIGHT. THE PERSISTENT
EASTERLY FLOW WILL RESULT IN LOCALLY HIGHER WAVES ALONG THE SOUTHERN
WI AND IL COAST LINE OF 5 TO 8 FT BY SUNDAY AFTERNOON. WAVES IN THE
IL NEARSHORE ZONES LOOK LIKE THEY WILL STAY JUST BELOW SMALL CRAFT
ADVISORY CRITERIA...THEREFORE WILL REFRAIN FROM ISSUING A SCY NOW.
HOWEVER...THE HIGHER WAVES AND ONSHORE FLOW ALONG THE IL NEARSHORE
ZONES DO POSE AN INCREASED RIP CURRENT RISK. THE RISK ALSO IS
INCREASED BY THE FACT THERE WILL PROBABLY BE AN ABOVE AVERAGE NUMBER
OF SWIMMERS AT THE BEACH THIS HOLIDAY WEEKEND. ISSUED A RIP CURRENT
STATEMENT FOR THE IL SIDE OF THE LAKE SATURDAY MORNING THROUGH
SUNDAY EVENING.

HIGH PRESSURE SPREADS ACROSS THE WESTERN GREAT LAKES TONIGHT.
MEANWHILE LOW PRESSURE THAT WAS FORMALLY HURRICANE ISAAC IS MOVING
NORTHWARD. THE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS WILL
TIGHTEN OVER SOUTHERN LAKE MICHIGAN. THEREFORE EAST WINDS WILL BE
STRONGER OVER THE SOUTHERN HALF OF THE LAKE. THE LOW WILL ENTER
SOUTH CENTRAL IL LATE SATURDAY AFTERNOON AND THEN TURN EASTWARD
PASSING SOUTH OF LAKE MICHIGAN. HIGH PRESSURE MOVES OVER THE LAKE
MONDAY NIGHT WITH WINDS WEAKENING ACROSS THE LAKE. ANOTHER TROUGH OF
LOW PRESSURE APPROACHES FROM THE WEST MID NEXT WEEK BUT CONFIDENCE
IS LOW ON THE EXACT TIMING OF THIS SYSTEM DUE TO GUIDANCE
INCONSISTENCIES.

JEE

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014...10 AM SATURDAY TO 7 PM
SUNDAY.

IN...NONE.
LM...NONE.
&&

AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

429 PM CDT FRI AUG 31 2012

.DISCUSSION...
349 PM CDT

RODRIGUEZ

.HYDROLOGY...
427 PM CDT

RODRIGUEZ

.AVIATION...

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

* TIMING WIND SHIFT FROM WSW TO NE WITH COLD FRONT SINKING FROM
SE AND FAR SW WI DOWN ACROSS THE LOCAL AREA TOWARD EVENING.

* TIMING ONSET AND NORTHWARD EXTEND OF SHOWERS/RAIN ASSOCIATED
WITH T.D. ISAAC ON SAT.

TRS

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

TRS

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

* HIGH CONFIDENCE IN WIND TRENDS.

* MODERATE CONFIDENCE IN TIMING OF THE COLD FRONT PASSAGE THIS
EVENING AND THE ACCOMPANYING WIND SHIFT.

* HIGH CONFIDENCE IN VFR AND DRY CONDITIONS THROUGH THE NIGHT AND
EARLY SAT MORNING.

* MODERATE CONFIDENCE IN PREVAILING VFR CONTINUING FROM MID SAT
MORNING ON WITH ONLY AREAS/OCCASIONAL MVFR.

TRS

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

SATURDAY NIGHT...

SUNDAY...CHC OF RA/SHRA. MVFR/IFR POSSIBLE.

MONDAY...SLGT CHC SHRA/TSRA. MVFR POSSIBLE.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...CHC SHRA/TSRA. OTHERWISE VFR.

RATZER

.MARINE...
351 PM CDT

JEE

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014...10 AM SATURDAY TO 7 PM
SUNDAY.

IN...NONE.
LM...NONE.
&&

AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

353 PM CDT FRI AUG 31 2012

.DISCUSSION...
349 PM CDT

RODRIGUEZ

.HYDROLOGY...
441 AM CDT

NOT MUCH HAS CHANGED WITH THE TRACK OF THE REMNANTS OF TROPICAL
CYCLONE ISAAC. THE SYSTEM IS EXPECTED TO TRACK FROM ITS CURRENT
POSITION ACROSS WEST CENTRAL ARKANSAS...NORTHWARD TO CENTRAL
MISSOURI BY EARLY SATURDAY...AND THEN TRANSITION TO THE EAST ALONG
THE INTERSTATE 70 CORRIDOR THIS WEEKEND. DUE TO THE TROPICAL
NATURE OF THE STORM SYSTEM...A VERY HIGH AMOUNT OF ATMOSPHERIC
MOISTURE WILL ACCOMPANY THE SYSTEM. BECAUSE OF THIS...IT APPEARS
LIKELY THAT PERIODS OF HEAVY RAINFALL WILL OCCUR ACROSS CENTRAL
ILLINOIS AND PORTIONS OF NORTHWESTERN INDIANA ON SATURDAY THROUGH
SUNDAY. THE LATEST FORECAST TOTAL RAINFALL AMOUNTS CALLS FOR
BETWEEN THREE TO SIX INCHES ACROSS THE FAR SOUTHERN COUNTIES OF THE
CWA...LIVINGSTON/FORD/IROQUOIS/BENTON...WITH AMOUNTS DROPPING OFF
RAPIDLY TO THE NORTH. IT IS POSSIBLE THAT LOCATIONS NEAR THE
WISCONSIN BORDER MAY SEE VERY LITTLE RAINFALL.

THE RIVER BASINS MOSTLY LIKELY TO SEE THE GREATEST IMPACT WILL BE
THE KANKAKEE...IROQUOIS AND VERMILION RIVERS AND SMALLER RIVERS
AND CREEKS DRAINING INTO THEM. GIVEN THE SLOW MOVEMENT TO THE
SYSTEM AND THE COPIOUS AMOUNTS OF DEEP LAYER MOISTURE LIKELY TO BE
PRESENT...WIDESPREAD RAINFALL AMOUNTS OF 2 INCHES PER SIX HOUR
PERIOD IS POSSIBLE...AND LOCALLY HIGHER AMOUNTS ARE CERTAINLY NOT
OUT OF THE QUESTION. THIS AREA WILL NEED TO BE UNDER CONSIDERATION
FOR AN AREAL FLOOD WARNING

FOR LOCATIONS NORTH OF THE HEAVY RAINFALL AXIS...NORTHWARD TO THE
I-88 CORRIDOR...1 TO 2 INCHES OF TOTAL RAINFALL IS POSSIBLE AND
THE MORE FLASHY BASINS OF THE SOUTHERN PORTIONS OF THE CHICAGO
METRO AREA COULD SEE FLOODING PROBLEMS AS WELL.

KREIN/KJB

.AVIATION...

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

* TIMING WIND SHIFT FROM WSW TO NE WITH COLD FRONT SINKING FROM
SE AND FAR SW WI DOWN ACROSS THE LOCAL AREA TOWARD EVENING.

* TIMING ONSET AND NORTHWARD EXTEND OF SHOWERS/RAIN ASSOCIATED
WITH T.D. ISAAC ON SAT.

TRS

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

TRS

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

* HIGH CONFIDENCE IN WIND TRENDS.

* MODERATE CONFIDENCE IN TIMING OF THE COLD FRONT PASSAGE THIS
EVENING AND THE ACCOMPANYING WIND SHIFT.

* HIGH CONFIDENCE IN VFR AND DRY CONDITIONS THROUGH THE NIGHT AND
EARLY SAT MORNING.

* MODERATE CONFIDENCE IN PREVAILING VFR CONTINUING FROM MID SAT
MORNING ON WITH ONLY AREAS/OCCASIONAL MVFR.

TRS

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

SATURDAY NIGHT...

SUNDAY...CHC OF RA/SHRA. MVFR/IFR POSSIBLE.

MONDAY...SLGT CHC SHRA/TSRA. MVFR POSSIBLE.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...CHC SHRA/TSRA. OTHERWISE VFR.

RATZER

.MARINE...
351 PM CDT

JEE

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014...10 AM SATURDAY TO 7 PM
SUNDAY.

IN...NONE.
LM...NONE.
&&

AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

351 PM CDT FRI AUG 31 2012

.DISCUSSION...
349 PM CDT

RODRIGUEZ

.HYDROLOGY...
441 AM CDT

KREIN/KJB

.AVIATION...

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

* TIMING WIND SHIFT FROM WSW TO NE WITH COLD FRONT SINKING FROM
SE AND FAR SW WI DOWN ACROSS THE LOCAL AREA TOWARD EVENING.

* TIMING ONSET AND NORTHWARD EXTEND OF SHOWERS/RAIN ASSOCIATED
WITH T.D. ISAAC ON SAT.

TRS

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

TRS

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

* HIGH CONFIDENCE IN WIND TRENDS.

* MODERATE CONFIDENCE IN TIMING OF THE COLD FRONT PASSAGE THIS
EVENING AND THE ACCOMPANYING WIND SHIFT.

* HIGH CONFIDENCE IN VFR AND DRY CONDITIONS THROUGH THE NIGHT AND
EARLY SAT MORNING.

* MODERATE CONFIDENCE IN PREVAILING VFR CONTINUING FROM MID SAT
MORNING ON WITH ONLY AREAS/OCCASIONAL MVFR.

TRS

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

SATURDAY NIGHT...

SUNDAY...CHC OF RA/SHRA. MVFR/IFR POSSIBLE.

MONDAY...SLGT CHC SHRA/TSRA. MVFR POSSIBLE.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...CHC SHRA/TSRA. OTHERWISE VFR.

RATZER

.MARINE...
246 AM CDT

MARINE FORECAST CONCERNS INCLUDE A PERIOD OF GUSTY SOUTHWEST WINDS
THIS MORNING AHEAD OF A COLD FRONT WHICH WILL SAG SOUTH ACROSS LAKE
MICHIGAN TODAY...AND A PERIOD OF MODEST EAST-NORTHEAST WINDS THIS
THE WEEKEND AS THE SURFACE LOW PRESSURE CIRCULATION ASSOCIATED WITH
TROPICAL DEPRESSION ISAAC MOVES SLOWLY SOUTH OF THE GREAT LAKES.

LOW PRESSURE WAS LOCATED OVER EASTERN QUEBEC EARLY THIS
MORNING...WITH A COLD FRONT TRAILING SOUTHWESTWARD ACROSS THE
NORTHERN LAKES AND INTO CENTRAL WISCONSIN. THIS COLD FRONT WILL
CONTINUE TO SAG SOUTH ACROSS LAKE MICHIGAN TODAY AS THE EASTERN
CANADIAN LOW CONTINUES TO MOVE AWAY. SOUTHWEST WINDS AHEAD OF THE
FRONT HAVE BEEN FAIRLY GUST PARTICULARLY OVER THE NORTHERN END OF
LAKE MICHIGAN...WITH SOME GUSTS AROUND 30 KTS NOTED ALONG THE
EASTERN SHORE NORTH OF MANISTEE AND AROUND CHARLEVOIX. THESE
STRONGER WINDS SHOULD DIMINISH THIS MORNING...AS THE LOW LEVEL JET
ASSOCIATED WITH A PASSING UPPER DISTURBANCE PULLS OF TO THE EAST.
WINDS WILL VEER TO THE NORTH BEHIND THE FRONT TODAY AND TO
NORTH-NORTHEAST TONIGHT...AS THE FRONT CONTINUES TO DRIFT TO THE
SOUTH AND HIGH PRESSURE SPREADS ACROSS THE NORTHERN LAKES. THE HIGH
WILL DRIFT SOUTHEAST ACROSS THE NORTHERN/EASTERN LAKES SATURDAY AND
SUNDAY...WHILE THE AREA OF SURFACE LOW PRESSURE FROM TROPICAL
DEPRESSION ISAAC SLOWLY LIFTS ACROSS THE LOWER MISSOURI VALLEY
THROUGH TONIGHT...THEN TURNS EAST AND DRIFTS ACROSS SOUTH CENTRAL
IL/IND AS IT FILLS DURING THE REMAINDER OF THE WEEKEND. FORECAST
MODEL GUIDANCE CONTINUES TO EXHIBIT DIFFERENCES IN THE EXACT AND
STRENGTH OF ISAAC DURING THIS PERIOD...THOUGH THE PASSAGE OF THIS
LOW SOUTH OF THE LAKES SHOULD RESULT IN A PERIOD OF ENHANCED
EASTERLY FLOW PARTICULARLY ON THE SOUTHERN HALF OF LAKE MICHIGAN
ESPECIALLY LATE TONIGHT INTO SUNDAY. EAST WINDS TOPPING OUT IN THE
20-25 KT RANGE DURING THIS PERIOD MAY NECESSITATE SMALL CRAFT
ADVISORIES ALONG THE WESTERN SHORE OF SOUTHERN LAKE MICHIGAN OVER
THE WEEKEND...BEFORE THE LOW WEAKENS AND LOOSENS THE GRADIENT ACROSS
THE LAKE BY MONDAY.

RATZER

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ006-ILZ014...10 AM SATURDAY TO 7 PM
SUNDAY.

IN...NONE.
LM...NONE.
&&

AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

1112 AM CDT FRI AUG 31 2012

.DISCUSSION...
340 AM CDT

THE MAIN FORECAST CONCERNS CONTINUE TO CENTER ON THE HEAVY RAINFALL
POTENTIAL ACROSS PORTIONS OF THE AREA THIS WEEKEND AS THE REMNANTS
OF HURRICANE ISSAC MOVE ACROSS THE CENTRAL MISSISSIPPI
VALLEY. I HAVE FOLLOWED CLOSER TO THE 00 UTC ECMWF...GFS AND UKMET
FOR THIS FORECAST PERIOD AS THEY HAVE A DECENT HANDLE ON TRACKING
THE REMNANTS UP ACROSS EAST CENTRAL MISSOURI EASTWARD ACROSS
CENTRAL ILLINOIS. THE NAM SOLUTION WAS REJECTED AS IT IS DOING A
POOR JOB WITH THE SYSTEM.

NO BIG CHANGES TO THE PREVIOUS THINKING. THE CENTER OF THE STORM IS
NOW LOCATED ACROSS WEST CENTRAL ARKANSAS. IT WILL SLOWLY LIFT
NORTHWARD ACROSS SOUTHWESTERN MISSOURI LATER THIS AFTERNOON AND THEN
THE SYSTEM IS EXPECTED TO BEGIN TO MOVE MORE EASTERLY LATER TONIGHT
AS IT BECOMES INFLUENCED BY THE WESTERLIES. IT STILL APPEARS THE
CENTER OF THE SYSTEM WILL PASS SOMEWHERE AROUND OR JUST NORTH OF THE
ST LOUIS AREA AND TRANSVERSE THE CENTRAL SECTIONS OF ILLINOIS.
ULTIMATELY THIS WILL RESULT IN THE HEAVIEST RAINFALL ACROSS MY
SOUTHERN COUNTIES...SOUTH OF INTERSTATE 80. IT APPEARS THERE WILL BE
A VERY SHARPE GRADIENT ACROSS NORTHERN ILLINOIS SOMEWHERE AROUND THE
I 88 CORRIDOR. THE NORTHERN SUBURBS OF CHICAGO MAY ONLY GET MINOR
AMOUNTS UP TO A QUARTER INCH...WHILE THE SOUTHERN BURBS GET MORE
THAN AN INCH. BY FAR THE HEAVIEST AMOUNTS LOOK TO BE ACROSS MY
SOUTHERN COUNTIES FROM SOUTHERN LA SALLE EASTWARD THROUGH KANKAKEE
AND POINTS SOUTH. IN THESE AREAS 3 TO 6 INCHES ARE POSSIBLE...WITH
LOCALLY HIGH AMOUNTS POSSIBLE. DUE TO THE EXPECTED RAINFALL...I
LOWER TEMPERATURES INTO THE 70S FOR HIGHS...MANY SOUTH FOR SATURDAY
AND SUNDAY. THE HEAVY RAIN THREAT WILL END FROM WEST TO EAST ON
LATER ON SUNDAY AS THE SYSTEM MOVE EAST AND RAPIDLY WEAKENS.

IN THE EXTENDED PERIOD OVERALL CONFIDENCE IS LOW AS IT APPEARS THE
WESTERLIES WILL BECOME ACTIVE ACROSS NORTH AMERICA. THIS WILL LIKELY
DRIVE A COUPLE OF POTENT MID/UPPER TROUGHS ACROSS SOUTHERN CANADA.
THE GUIDANCE SUGGESTS THAT A TROUGH WILL TRY TO DIG ACROSS THE NORTH
CENTRAL CONUS BY MID TO LATE WEEK. HOWEVER...THERE IS A SIGNIFICANT
AMOUNT OF SPREAD AMONGST THE MODEL ENSEMBLES...INDICATING LARGE
TIMING UNCERTAINTIES. IT DOES APPEAR THERE WILL BE A CHANCE OF
THUNDERSTORMS SOMETIME EITHER WEDNESDAY NIGHT OR THURSDAY AS A COLD
FRONT DROPS ACROSS THE AREA. TEMPERATURES DURING THE PERIOD WILL
LIKELY BE NEAR AVERAGE EARLY ON IN THE WEEK...THEN TRENDING TO BELOW
AVERAGE AS A COOL AIR MASS LOOKS TO SET UP ACROSS THE REGION BEHIND
THIS COLD FRONT.

KJB

.HYDROLOGY...
441 AM CDT

THE RIVER BASINS MOSTLY LIKELY TO SEE THE GREATEST IMPACT WILL BE
THE KANKAKEE...IROQUOIS AND VERMILLION RIVERS AND SMALLER RIVERS
AND CREEKS DRAINING INTO THEM. GIVEN THE SLOW MOVEMENT TO THE
SYSTEM AND THE COPIOUS AMOUNTS OF DEEP LAYER MOISTURE LIKELY TO BE
PRESENT...WIDESPREAD RAINFALL AMOUNTS OF 2 INCHES PER SIX HOUR
PERIOD IS POSSIBLE...AND LOCALLY HIGHER AMOUNTS ARE CERTAINLY NOT
OUT OF THE QUESTION. THIS AREA WILL NEED TO BE UNDER CONSIDERATION
FOR AN AREAL FLOOD WARNING

KREIN/KJB

.AVIATION...

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

* MARGINAL GUSTINESS OF 15-20 KT TIL THICK CIRRUS STRATUS
OVERSPREADS AROUND NOON.

* TIMING WIND SHIFT FROM WSW TO NE WITH COLD FRONT SINKING FROM
SE AND FAR SW WI DOWN ACROSS AREA TOWARD EVENING.

* SMALL POTENTIAL FOR SHRA/ISOLD TS FAR SOUTHERN WI INTO NE AND
FAR N CENTRAL IL BORDER MID-LATE AFTERNOON.

* POTENTIAL FOR SHOWERS ASSOCIATED WITH TD ISAAC MAINLY BEYOND
12Z SATURDAY.

TRS

//DISCUSSION...UPDATED 14Z...

ONLY VERY MINOR TWEAKS MADE TO 14Z TAFOR. SSW-SW LOW LEVEL WINDS
ADVECTING MID-UPPER 60S SURFACE DEW POINTS OVER THE AREA AT MID
MORNING WITH UPPER 60-LOWER 70S ACROSS CENTRAL IL. WITH CONTINUED
HEATING DURING THE LATE MORNING THE LOW LEVEL MOISTURE ADVECTION
WILL BE OFFSET BY DEEPENING OF MIXING IN THE BOUNDARY LAYER.
EXPECT DEW POINTS TO BE IN THE MID-UPPER 60S DURING THE
AFTERNOON. THIS GIVES CONVECTIVE TEMPERATURES IN THE UPPER 80S
WHICH IS FORECAST TO REACH AROUND NOON. THOUGH NOT OPERATIONALLY
SIGNIFICANT DID INCLUDE A FORECAST STARTING AT 17Z INCLUDING
HIGHER BASED CU DEVELOPING.

MODELS SHOW LOW LEVEL CONVERGENCE ALONG THE WI COLD FRONT
DROPPING TOWARD THE IL BORDER THIS AFTERNOON...AS WELL AS IN NE
ALONG A LAKE BREEZE BOUNDARY PUSHING INLAND. FORECAST SOUNDINGS
FROM THE 12Z RUC13 SHOW MINIMAL CIN OVER CHI AREA DURING THE
LATER AFTERNOON ALONG WITH DECENT CAPE VALUES. LOW LEVEL WARMING
AND CONVERGENCE WOULD FAVOR ISOLD TO SCT TS DEVELOPMENT ALONG THE
COLD FRONT AND LAKE BREEZE MID-LATE AFTERNOON...WHILE SUBSIDENCE
INN THE MID AND UPPER LEVELS ON THE PERIPHERY OF ISSAC REMNANTS
SPREAD OVER THE LOCAL AREA. THIS WITH INCREASING CLOUDS CUTTING
SURFACE HEATING DURING THE LATER AFTERNOON WOULD DISCOURAGE AN TS
DEVELOPMENT. THREAT TOO LOW AT THIS TIME TO INCLUDE ANY MENTION
IN TAFOR THOUGH LOW COVERAGE NOT TS LATE AFTERNOON NOT TOTALLY
OUT OF THE QUESTION.

TRS

PREVIOUS DISCUSSION...UPDATED 12Z...

LITTLE CHANGE IN AVIATION FORECAST THINKING FROM 06Z ISSUANCE.
MAIN FOCUS REMAINS ON TIMING OF WEAK COLD FRONT AND WIND SHIFT
FROM WEST-SOUTHWEST TO NORTHEAST TOWARD EVENING...THEN INCREASING
HIGH CLOUDS THIS AFTERNOON AND EVENTUAL PRECIP POTENTIAL SATURDAY
AS THE REMAINS OF TROPICAL DEPRESSION ISAAC MOVE SLOWLY INTO
IL/IND.

THE COLD FRONT...WHICH WAS FROM EAST CENTRAL WI TO NORTH CENTRAL
IA AT 11Z...WILL CONTINUE TO MOVE SLOWLY SOUTH TOWARD THE
TERMINALS TODAY. VAD WIND PROFILES INDICATE THE PRESENCE OF A 35
KT SPEED MAX ABOVE THE BOUNDARY LAYER AT AROUND 1000 FT AGL THIS
MORNING WHICH WILL RESULT IN A PERIOD OF MARGINAL LLWS FOR THE
NEXT HOUR OR TWO UNTIL THE BOUNDARY LAYER BECOMES MORE DEEPLY
MIXED. WITH MIXING...SOUTHWEST WINDS WILL BECOME A BIT BREEZY BY
MID-MORNING WITH GUSTS APPROACHING 20 KTS. THE GRADIENT SHOULD
WEAKEN THIS AFTERNOON AS THE COLD FRONTAL TROUGH APPROACHES
HOWEVER...ALLOWING WINDS TO DECREASE A BIT. TIMING OF THE FRONTAL
PASSAGE AND A WIND SHIFT FROM WEST-SOUTHWEST TO NORTHEAST STILL
APPEARS TO BE ON TRACK FOR THE 23-01Z PERIOD ACROSS THE
TERMINALS...WITH WINDS REMAINING NORTHEAST AROUND 10 KTS
OVERNIGHT.

ATTENTION THEN TURNS TO THE REMAINS OF ISAAC...WHICH LIFT SLOWLY
ACROSS THE MISSOURI VALLEY TODAY...THEN DRIFT EAST ACROSS CENTRAL
IL/IND SAT. THIS SYSTEM SHOULD PRODUCE JUST INCREASING HIGH/MID
CLOUDS ACROSS THE AREA LATER TODAY AND TONIGHT...WITH GUIDANCE
INDICATING RAIN SHOWERS MOVING INTO THE TERMINALS GENERALLY AFTER
12Z SATURDAY MORNING. ALL MODELS INDICATE A SHARP NORTHERN CUTOFF
TO THE PRECIP...WITH THAT CUTOFF LIKELY SOMEWHERE OVER NORTHERN
IL. AT THIS DISTANCE HAVE INDICATED A VICINITY SHOWER MENTION FOR
ORD IN THE FINAL HOURS OF THE 30 HR FORECAST...WITH ROOM FOR
FURTHER DEFINITION IN SUBSEQUENT FORECASTS. WITH THE LOW PRESSURE
CENTER MOVING INTO IL...THE PRESSURE GRADIENT LOOKS TO TIGHTEN
ENOUGH FOR WINDS TO COME UP INTO THE 10-15 KT RANGE SATURDAY
MORNING.

RATZER

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

* HIGH CONFIDENCE IN WIND TRENDS PRIOR TO WIND SHIFT TOWARD
EVENING.

* MEDIUM CONFIDENCE IN WIND SHIFT TIMING WITH COLD FRONT.

* MEDIUM CONFIDENCE IN SHOWERS REMAINING S OF ORD/MDW THROUGH 12Z
SAT.

TRS

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

SATURDAY NIGHT...

SUNDAY...CHC OF RA/SHRA. MVFR/IFR POSSIBLE.

MONDAY...SLGT CHC SHRA/TSRA. MVFR POSSIBLE.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...CHC SHRA/TSRA. OTHERWISE VFR.

RATZER

.MARINE...
246 AM CDT

RATZER

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

1007 AM CDT FRI AUG 31 2012

.DISCUSSION...
340 AM CDT

KJB

.HYDROLOGY...
441 AM CDT

NOT MUCH HAS CHANGED WITH THE TRACK OF THE REMNANTS OF TROPICAL
CYCLONE ISAAC. THE SYSTEM IS EXPECTED TO TRACK FROM ITS CURRENT
POSITION ACROSS WEST CENTRAL ARKANSAS...NORTHWARD TO CENTRAL
MISSOURI BY EARLY SATURDAY...AND THEN TRANSITION TO THE EAST ALONG
THE INTERSTATE 70 CORRIDOR THIS WEEKEND. DUE TO THE TROPICAL
NATURE OF THE STORM SYSTEM...A VERY HIGH AMOUNT OF ATMOSPHERIC
MOISTURE WILL ACCOMPANY THE SYSTEM. BECAUSE OF THIS...IT APPEARS
LIKELY THAT PERIODS OF HEAVY RAINFALL WILL OCCUR ACROSS CENTRAL
ILLINOIS AND PORTIONS OF NORTHWESTERN INDIANA ON SATURDAY THROUGH
SUNDAY. THE LATEST FORECASTED TOTAL RAINFALL AMOUNTS CALLS FOR
BETWEEN THREE TO SIX INCHES ACROSS THE FAR SOUTHERN COUNTIES OF THE
CWA...LIVINGSTON/FORD/IROQUOIS/BENTON...WITH AMOUNTS DROPPING OFF
RAPIDLY TO THE NORTH. IT IS POSSIBLE THAT LOCATIONS NEAR THE
WISCONSIN BORDER MAY SEE VERY LITTLE RAINFALL.

KREIN/KJB

.AVIATION...

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

*MARGINAL GUSTINESS AS BOUNDARY LAYER DEEPENS WITH HEATING...
MIXING DOWN 15-20 KT TO THE SURFACE.

* TIMING WIND SHIFT FROM WSW TO NE WITH COLD FRONT SINKING FROM N
CENTRAL AND SW WI DOWN ACROSS AREA TOWARD EVENING.

* SMALL POTENTIAL FOR SHRA/ISOLD TS FAR SOUTHERN WI INTO NE AND
FAR N CENTRAL IL BORDER MID-LATE AFTERNOON.

* POTENTIAL FOR SHOWERS ASSOCIATED WITH TD ISAAC MAINLY BEYOND
12Z SATURDAY.

RATZER

//DISCUSSION...UPDATED 14Z...

TRS

PREVIOUS DISCUSSION...UPDATED 12Z...

RATZER

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

* HIGH CONFIDENCE IN WIND TRENDS PRIOR TO WIND SHIFT TOWARD
EVENING.

* MEDIUM CONFIDENCE IN WIND SHIFT TIMING WITH COLD FRONT.

* MEDIUM CONFIDENCE IN SHOWERS REMAINING S OF ORD/MDW THROUGH 12Z
SAT.

TRS

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

SATURDAY NIGHT...

SUNDAY...CHC OF RA/SHRA. MVFR/IFR POSSIBLE.

MONDAY...SLGT CHC SHRA/TSRA. MVFR POSSIBLE.

TUESDAY...VFR.

WEDNESDAY...VFR.

THURSDAY...CHC SHRA/TSRA. OTHERWISE VFR.

RATZER

.MARINE...
246 AM CDT

RATZER

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&

AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

1245 PM EDT FRI AUG 31 2012

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

.SYNOPSIS...
ISSUED AT 234 AM EDT FRI AUG 31 2012

THE REMNANTS OF HURRICANE ISAAC WILL BE THE MAIN WEATHER FEATURE
OVER THE NEXT SEVERAL DAYS. HIGH CLOUDS ARE EXPECTED TO ARRIVE
TODAY AS THE REMNANTS MOVE FROM ARKANSAS INTO SOUTHERN MISSOURI.

RAIN SHOWERS...ALONG WITH SOME HEAVY RAIN IS EXPECTED TO ARRIVE ON
SATURDAY AFTERNOON AND SUNDAY AS THE REMNANTS BEGIN TO PUSH
NORTHEAST INTO ILLINOIS.

SCATTERED RAIN SHOWERS ARE EXPECTED TO LINGER ACROSS CENTRAL
INDIANA ON MONDAY AS THE REMNANTS SLOWLY WEAKEN AND SLOWLY
MEANDER EASTWARD INTO THE OHIO VALLEY.

AS THE REMNANTS DEPART AS LOW PRESSURE ON TUESDAY NIGHT...HIGH
PRESSURE WILL BUILD ACROSS INDIANA BRINGING DRY WEATHER FOR THE
MIDDLE OF THE NEXT WORK WEEK. ANOTHER COLD FRONT WILL APPROACH OUR
REGION THURSDAY AS A STRONG UPPER TROUGH DIGS INTO THE UPPER
MIDWEST.

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1020 AM AM EDT FRI AUG 31 2012

VISIBLE SATELLITE SHOWS AN EXTENSIVE AREA OF MID CLOUDS WERE
SPREADING NORTHEAST ACROSS OUR REGION. SOME OF THIS MAY THIN OUT
THIS AFTERNOON...SO WILL GO PARTLY CLOUDY MOST SECTIONS TODAY.
THE BIGGEST QUESTION WILL BE WHAT TO DO WITH TEMPERATURES. BOTH THE
NAM AND 12Z RUC STILL INDICATE TEMPERATURES IN THE LOWER 90S THIS
AFTERNOON. THIS SEEMS A BIT WARM GIVEN THAT THEY WERE SEVERAL
DEGREES TOO WARM YESTERDAY WITH FULL SUNSHINE. WILL RAISE
TEMPERATURES JUST A TAD TODAY GIVEN THAT CLOUDS MAY THIN OUT AND
MODELS ARE RUNNING SO WARM.

IN REGARDS TO PRECIP RADAR SHOWS A BAND OF MOSTLY VIRGA SPREADING
NORTH ACROSS OUR STATE. RAPID REFRESH SHOWS A 2ND BAND OF SHOWERS
AND THUNDERSTORMS WILL BE ALONG OUR WESTERN BORDER BY LATE
AFTERNOON. WILL RAISE POPS A LITTLE ALONG OUR WEST AND ADD SLIGHT
CHANCE POPS OVER MOST OF OUR FAR SOUTH THIS AFTERNOON.

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 234 AM EDT FRI AUG 31 2012

MODELS ARE PRETTY CLOSE WITH THE HANDLING OF THE REMNANTS...BUT AS
WE APPROACH SUNDAY AFTERNOON THE NAM SOLUTION OF KEEPING THE LOW
CENTERED OVER MISSOURI DOESN/T MAKE MUCH SENSE...AS WELL AS THE
LACK OF EASTERN PROPAGATION. THUS WILL USE A BLEND INITIALLY BUT
TREND TOWARD THE GFS BY SUNDAY AND SUNDAY NIGHT.

TWO FEATURES ARE GOING TO COME TOGETHER TO HELP PRODUCE RAIN
ACROSS CENTRAL INDIANA THIS PERIOD. THE APPROACHING REMNANTS OF
ISAAC COMBINING WITH A FRONTAL BOUNDARY OVER THE UPPER MIDWEST
WHICH IS EXPECTED TO SAG SOUTHWARD AND HELP PROVIDE AN EXTRA LIFT
MECHANISM ON SATURDAY AND SUNDAY.

CLOUDS WILL BE EXPECTED TO INCREASE BY TONIGHT AND A FEW SHOWERS
COULD REACH THE AREA AS BANDS OF PRECIP CONTINUE TO SWIRL AROUND
THE LOW WHICH IS EXPECTED TO DRIFT INTO MISSOURI. GIVEN THE
CURRENT STRUCTURE OF THE SYSTEM...AND AS DRY AIR CONTINUES TO
INFILTRATE THE SYSTEM AS IT APPROACHES...A FEW SHOWERS CANNOT BE
RULED OUT REACHING CENTRAL INDIANA OVERNIGHT...PARTICULARLY
ACROSS THE WEST WHERE PROXIMITY IS BEST. WILL KEEP SOME PRECIP
CHANCES FOR TONIGHT IN TO FORECAST PARTICULAR ACROSS THE WEST.
WITH THE ARRIVAL OF A VERY MOIST AIR MASS WILL TREND LOWS HIGHER
THAN MAVMOS.

AS THE FRONTAL BOUNDARY SAGS SOUTHWARD AND BEGINS TO INTERACT WITH
THE REMNANTS OF ISAAC ON SATURDAY AFTERNOON...MORE WIDESPREAD RAIN
SHOWERS ARE EXPECTED TO DEVELOP. LOW LEVEL Q VECTORS DISPLAY
STRONG CONVERGENCE ACROSS THE AREA BY SATURDAY AFTERNOON AND
EVENING AS FORECAST SOUNDINGS REVEAL DEEP MOISTURE PRESENT. WILL
STICK WITH NEAR CATEGORICAL POPS FOR SATURDAY...WITH BEST CHANCES
STARTING THIS AFTERNOON...ALTHOUGH CONFIDENCE REGARDING PRECISE
TIMING ON THE START OF RAINFALL REMAINS LOW DUE TO THE SLOW
ARRIVAL OF THE APPROACHING SYSTEM. WILL ALSO TREND HIGH TEMPS
COOLER THAN MAVMOS.

GFS AND NAM Q VECTORS CONTINUE TO SUGGEST STRONG LOWER LEVEL
CONVERGENCE ON SATURDAY NIGHT AND ON SUNDAY AND THE FRONTAL
BOUNDARY FROM THE NORTH STALLS OVER THE REGION. FORECAST SOUNDINGS
CONTINUE TO SHOW DEEP MOISTURE AVAILABLE WITH THE LINGERING
TROPICAL REMNANTS. WILL CONTINUE TO KEEP HIGH POPS ONGOING ON
SATURDAY AND SUNDAY...WITH LOW TEMPS WARMER THAN GUIDANCE AND HIGH
TEMPS COOLER DUE TO EXPECTED CLOUDS AND RAIN. LOWER LEVEL PRESSURE
GRADIENT APPEARS TO GET WEAKER AS THE SYSTEM ARRIVES...AND
ALTHOUGH SOME GUSTY WINDS CANNOT BE RULED OUT...ANY GUSTS SHOULD
BE LESS THAN PREVIOUSLY EXPECTED.

WITH THE SLOW PROGRESSION OF THE SYSTEM...AS THE GFS DEPICTS THE
LOW PRESSURE CENTER ONLY REACHING WESTERN INDIANA BY SUNDAY NIGHT
WILL NEED TO CONTINUE WITH SOME POPS ON SUNDAY NIGHT. ALTHOUGH
BEST FORCING WILL REMAIN WELL SOUTHEAST OF THE LOW...OVER
SOUTHEAST INDIANA AND KENTUCKY AS THE FRONTAL BOUNDARY IS EXPECTED
TO SAG SOUTHWARD TOWARD THE OHIO RIVER THEN. FORECAST SOUNDINGS
CONTINUE TO INDICATE DEEP MOISTURE AVAILABLE...BUT WITH MORE
LIMITED FORCING. WILL TREND LOWS WARMER THAN GUIDANCE GIVEN THE
CLOUDS AND MOIST...TROPICAL AIR MASS THAT WILL BE PLACE.

SUMMING UP...BEST CHANCES FOR HEAVY RAINS CONTINUE TO APPEAR TO BE
SATURDAY THROUGH SUNDAY...AND THIS PERIOD WILL ALSO BE THE PERIOD
THAT HAS THE BEST CHANCES FOR FLOODING.

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 234 AM EDT FRI AUG 31 2012

ENSEMBLE DATA INDICATE REMNANTS OF TROPICAL CYCLONE ISAAC MAY STILL
BE IN THE PROCESS OF PASSING ACROSS THE AREA ON MONDAY.
OTHERWISE...THE DATA INDICATE THE JET STREAM WILL BE GRADUALLY
SINKING SOUTH WITH TIME AS A SERIES OF DISTURBANCES MOVE EAST
SOUTHEAST ACROSS THE UPPER GREAT LAKES.

LOOKS LIKE A RATHER UNSETTLED EXTENDED PERIOD...WITH THE POTENTIAL
FOR A COUPLE OF FRONTAL PASSAGES IN ADDITION TO WHAT IS LEFT OF
ISAAC. AT THIS POINT...THE ENSEMBLES SUGGEST A PRECIPITATION THREAT
PRETTY MUCH EVERY DAY EXCEPT FOR THE TUESDAY NIGHT AND WEDNESDAY
TIME FRAME. WILL GO WITH POPS ON MONDAY...TUESDAY...AND
THURSDAY...AND KEEP WEDNESDAY DRY.

.AVIATION /DISCUSSION FOR THE 311800Z TAFS/...

ISSUED AT 1245 PM EDT FRI AUG 31 2012

CONDITIONS WILL DETERIORATE TO MVFR TONIGHT AND REMAIN SO FOR MUCH
OF SATURDAY.

CONFIDENCE IS BELOW AVERAGE WITH FORECAST DUE TO CONTINUING
UNCERTAINTY IN TIMING AND PATH OF ISAAC REMNANTS AND UNCERTAINTIES
IN WHERE HEAVIER RAIN WILL DEVELOP.

THROUGH 00Z OR SO ONLY EXPECT SCATTERED LOW CLOUDS AND BROKEN MID
CLOUDS. THERE WILL BE SOME LIGHT SHOWER ACTIVITY...BUT MOST OF THE
SHOWERS WILL BE CONFINED TO AREAS NEAR KHUF AND KLAF. VISIBILITIES
WILL BE MAINLY VFR IN THE SHOWERS...BUT BRIEF MVFR IS NOT OUT OF THE
QUESTION.

OTHERWISE EXPECT MVFR CLOUDS TO MOVE IN OVERNIGHT AS MOISTURE
CONTINUES TO INCREASE AHEAD OF REMNANTS OF ISAAC. RAIN WILL
GRADUALLY BECOME MORE WIDESPREAD...ESPECIALLY ACROSS THE WESTERN
SITES. HEAVIER RAIN SHOULDN/T ARRIVE UNTIL AFTER THE TAF PERIOD.

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS...PUMA
NEAR TERM...JH
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...50

AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

1030 AM EDT FRI AUG 31 2012

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

.SYNOPSIS...
ISSUED AT 234 AM EDT FRI AUG 31 2012

THE REMNANTS OF HURRICANE ISAAC WILL BE THE MAIN WEATHER FEATURE
OVER THE NEXT SEVERAL DAYS. HIGH CLOUDS ARE EXPECTED TO ARRIVE
TODAY AS THE REMNANTS MOVE FROM ARKANSAS INTO SOUTHERN MISSOURI.

RAIN SHOWERS...ALONG WITH SOME HEAVY RAIN IS EXPECTED TO ARRIVE ON
SATURDAY AFTERNOON AND SUNDAY AS THE REMNANTS BEGIN TO PUSH
NORTHEAST INTO ILLINOIS.

SCATTERED RAIN SHOWERS ARE EXPECTED TO LINGER ACROSS CENTRAL
INDIANA ON MONDAY AS THE REMNANTS SLOWLY WEAKEN AND SLOWLY
MEANDER EASTWARD INTO THE OHIO VALLEY.

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1020 AM AM EDT FRI AUG 31 2012

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 234 AM EDT FRI AUG 31 2012

SUMMING UP...BEST CHANCES FOR HEAVY RAINS CONTINUE TO APPEAR TO BE
SATURDAY THROUGH SUNDAY...AND THIS PERIOD WILL ALSO BE THE PERIOD
THAT HAS THE BEST CHANCES FOR FLOODING.

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 234 AM EDT FRI AUG 31 2012

.AVIATION /DISCUSSION FOR THE 311430Z TAF UPDATE/...

ISSUED AT 1030 AM EDT FRI AUG 31 2012

KIND TAF LOOKS GOOD. ONLY MINOR CHANGE TO WIND DIRECTION MADE. THERE
COULD BE SOME SPRINKLES/LIGHT SHOWERS BY AFTERNOON...BUT THESE WILL
NOT LOWER VISIBILITY BELOW VFR.

PREVIOUS DISCUSSION FOLLOWS...
CLOUD COVER WILL BE INCREASING TODAY...BUT CEILINGS SHOULD REMAIN
WELL ABOVE 050 THROUGH 010000Z. SOME DIURNAL CLOUD COVER BASED
AROUND 030 POSSIBLE AFTER 311500Z.

SOME LOW POTENTIAL FOR WIDELY SCATTERED CONVECTION BY THE MID
AFTERNOON HOURS...ESPECIALLY OVER THE MORE SOUTHERN TAF SITES...AS A
VORTICITY LOBE SWINGS INTO THE AREA FROM THE SOUTH AND CONVECTIVE
TEMPERATURES ARE WITHIN REACH. HOWEVER...CHANCES FOR A DIRECT IMPACT
AT A PARTICULAR TAF SITE TOO LOW TO MENTION AT THIS POINT.

NO PROLONGED VISIBILITY RESTRICTIONS...SURFACE WINDS GENERALLY UNDER
12 KTS THROUGH 010000Z.

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS...PUMA
NEAR TERM...JH
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS/50

AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

1020 AM EDT FRI AUG 31 2012

.UPDATE...
NEAR TERM SECTION FOR THE REST OF TODAY HAS BEEN UDPATED BELOW.

.SYNOPSIS...
ISSUED AT 234 AM EDT FRI AUG 31 2012

THE REMNANTS OF HURRICANE ISAAC WILL BE THE MAIN WEATHER FEATURE
OVER THE NEXT SEVERAL DAYS. HIGH CLOUDS ARE EXPECTED TO ARRIVE
TODAY AS THE REMNANTS MOVE FROM ARKANSAS INTO SOUTHERN MISSOURI.

RAIN SHOWERS...ALONG WITH SOME HEAVY RAIN IS EXPECTED TO ARRIVE ON
SATURDAY AFTERNOON AND SUNDAY AS THE REMNANTS BEGIN TO PUSH
NORTHEAST INTO ILLINOIS.

SCATTERED RAIN SHOWERS ARE EXPECTED TO LINGER ACROSS CENTRAL
INDIANA ON MONDAY AS THE REMNANTS SLOWLY WEAKEN AND SLOWLY
MEANDER EASTWARD INTO THE OHIO VALLEY.

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1020 AM AM EDT FRI AUG 31 2012

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 234 AM EDT FRI AUG 31 2012

SUMMING UP...BEST CHANCES FOR HEAVY RAINS CONTINUE TO APPEAR TO BE
SATURDAY THROUGH SUNDAY...AND THIS PERIOD WILL ALSO BE THE PERIOD
THAT HAS THE BEST CHANCES FOR FLOODING.

.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 234 AM EDT FRI AUG 31 2012

.AVIATION /DISCUSSION FOR THE 311200Z TAFS/...

ISSUED AT 632 AM EDT FRI AUG 31 2012

CLOUD COVER WILL BE INCREASING TODAY...BUT CEILINGS SHOULD REMAIN
WELL ABOVE 050 THROUGH 010000Z. SOME DIURNAL CLOUD COVER BASED
AROUND 030 POSSIBLE AFTER 311500Z.

NO PROLONGED VISIBILITY RESTRICTIONS...SURFACE WINDS GENERALLY UNDER
12 KTS THROUGH 010000Z.

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS...PUMA
NEAR TERM...JH
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS

AREA FORECAST DISCUSSION

NWS GRAY ME

743 PM EDT SAT SEP 1 2012

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TONIGHT AND WILL MOVE
OFFSHORE ON SUNDAY. HIGH PRESSURE WILL REMAIN ANCHORED OFF THE NEW
ENGLAND COAST ON MONDAY. A BROAD AREA OF LOW PRESSURE WILL
APPROACH FROM THE WEST ON TUESDAY AND WILL SLOWLY CROSS THE AREA
TUESDAY NIGHT AND WEDNESDAY. ANOTHER TROUGH OF LOW PRESSURE WILL
CROSS THE REGION ON THURSDAY. HIGH PRESSURE WILL BUILD IN FROM THE
WEST ON FRIDAY.

.NEAR TERM /TONIGHT/...
730PM UPDATE...HAVE UPDATED TO REMOVE RAIN CHANCES THIS EVENING AS
SHOWERS HAVE DISSIPATED. DRY AIR OVER INTERIOR MAINE SHOULD
PREVENT FOG FORMATION... HOWEVER... SOME HIGHER DEW POINTS OVER
NEW HAMPSHIRE INDICATE FOG IS LIKELY IN THE CONNECTICUT RIVER
VALLEY AGAIN BY MORNING AND POSSIBLE IN OTHER FAVORED SPOTS.

PREVIOUS DISCUSSION...
EXPECT MORE CLOUD COVER OVER NEW HAMPSHIRE AND EXTREME WESTERN
MAINE AND ISOLATED SHOWERS THROUGH SUNSET. SOME OF THIS MOISTURE
WILL DISSIPATE AFTER SUNSET...HOWEVER LIMITED MOISTURE MAY REMAIN
TRAPPED UNDERNEATH THE INVERSION. EXPECT PATCHY FOG TO DEVELOP
AS WELL OVER SOME OF THE INLAND VALLEYS BY LATE TONIGHT.
FINALLY...SOME CLOUDINESS WILL DEVELOP OUT AHEAD OF A SHORT WAVE
TROUGH DIGGING SOUTHEASTWARD FROM HUDSON BAY CANADA LATE TONIGHT.

WILL KEEP CONDITIONS DRY DURING THE OVERNIGHT HOURS. FEEL THE
LATEST HRRR MODEL IS OVERDOING THE PRECIPITATION OVER NEW HAMPSHIRE.
FOLLOWED A BLEND OF MAV/MET MOS NUMBERS FOR OVERNIGHT LOWS.

.SHORT TERM /SUNDAY AND SUNDAY NIGHT/...
UPPER TROUGH WILL ALREADY BE DIGGING ACROSS OUR FORECAST AREA AT
12Z. THIS WILL TRIGGER MORE CUMULUS DEVELOPMENT AS WELL AS
SCATTERED SHOWERS. CONVECTIVE PARAMETERS ARE MARGINAL FOR ANY
THUNDERSTORMS. HAVE NOT INCLUDED IN THE GRIDS AT THIS TIME...BUT
IT IS A SLIM POSSIBILITY. THE GREATEST INSTABILITY WILL BE IN
THE MOUNTAINS OF MAINE DURING THE EARLY AFTERNOON HOURS.

CLOUD COVER WILL KEEP MOST AREAS IN THE 60S...EXCEPT FOR SOUTHERN
NEW HAMPSHIRE.

SKIES BEGIN TO CLEAR LATER IN THE AFTERNOON AS SHORT WAVE ENERGY
PASSES EAST OF NEW ENGLAND. PATCHY LATE NIGHT FOG EXPECTED ONCE
AGAIN OVER THE INTERIOR VALLEYS. IT WILL BE A CHILLY NIGHT ONCE
AGAIN WITH OVERNIGHT LOWS IN THE LOWER 40S IN THE MOUNTAINS.

.LONG TERM /MONDAY THROUGH SATURDAY/...
IT APPEARS SOME OF THE MODELS WANT TO TAKE THE REMNANTS OF ISAAC
NORTHEASTWARD INTO NORTHERN NEW ENGLAND LATE TUESDAY AND THRU
WEDNESDAY INTO THURSDAY. THE NORTHERN STREAM TROF APPEARS STRONG
ENOUGH TO PICK UP THE REMNANTS THAT WERE DRIFTING NORTHEASTWARD
INTO THE OHIO VALLEY TUESDAY. THIS MAY MEAN A GOOD DEAL OF RAIN IN
THE MIDWEEK PERIOD. A LOT OF UNCERTAINTY BETWEEN THE MODELS WHILE
GFS THE WETTEST AND EURO TAKES A FASTER AND MORE SOUTHERLY TRACK
WITH MUCH LESS QPF. WILL STICK CLOSE TO THE GFS SOLUTION FOR NOW
FOR TIMING POPS AND QPF. WILL GO WITH LIKELY POPS FOR MIDWEEK
SINCE IT IS FAIRLY CERTAIN RAIN WILL BE ON THE WAY MIDWEEK. HIGH
PRESSURE WILL RETURN LATE IN THE WEEK WITH COOLER AND DRIER WEATHER.
STAYED CLOSE TO MAV TEMPS AND GMOS TEMPS FURTHER OUT IN TIME.

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...
VFR OVERNIGHT EXCEPT FOR VALLEY FOG AT WHITEFIELD AND LEBANON. LOW
CHANCE OF FOG AT CONCORD AS WELL. ANY FOG SHOULD LIFT BY 12-14Z
AND RETURN TO VFR CONDITIONS. SOME SHOWERS ARE POSSIBLE SUNDAY
AFTERNOON WITH A LOW CHANCE OF THUNDER. OTHERWISE VFR CONTINUES.

LONG TERM...
CONDITIONS TO BECOME GENERALLY IFR IN RAIN BY TUESDAY NIGHT AND
CONTINUED INTO THURSDAY FOLLOWED BY A RETURN TO VFR CONDITIONS
LATE IN THE WEEK AS A DRIER WESTERLY FLOW DEVELOPS.

.MARINE...
SHORT TERM...
WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA TONIGHT THROUGH
SUNDAY NIGHT.

LONG TERM...
A PROLONGED SOUTH TO SOUTHEASTERLY FLOW WILL DEVELOP WITH WINDS
GENERALLY BELOW SCA CRITERIA...BUT BY MIDWEEK SEAS WILL BUILD TO
WARRANT A SCA DUE TO SEAS AS A PROLONGED SOUTHERLY FLOW CONTINUES
THRU LATE IN THE WEEK.

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

UPDATE...KIMBLE

AREA FORECAST DISCUSSION

NWS GRAY ME

1152 AM EDT FRI AUG 31 2012

.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH FROM CANADA TODAY AND WILL PUSH
OFFSHORE THIS EVENING. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST TONIGHT AND SATURDAY AND WILL SHIFT OFFSHORE ON SUNDAY.
HIGH PRESSURE WILL REMAIN ANCHORED OFF THE COAST MONDAY. A COLD
FRONT WILL APPROACH FROM THE WEST MONDAY NIGHT AND WILL PUSH EAST
THROUGH NEW ENGLAND ON TUESDAY. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD IN FROM THE WEST ON WEDNESDAY AND WILL HOLD OVER THE AREA ON
THURSDAY.

.NEAR TERM /THROUGH TONIGHT/...
---1600Z UPDATE---
CLOUD COVER CONTINUES TO CAUSE ISSUES WITH FORECAST PACKAGE.
SHOWERS AND THUNDERSTORMS MOVING ACROSS NORTHERN VERMONT WILL
LIKELY HOLD TOGETHER LONG ENOUGH TO CROSS NEW HAMPSHIRE AND
SOUTHERN MAINE. WITH LITTLE IN THE WAY OF POSSIBLE SUNSHINE...WILL
CUT MAX TEMPERATURES SIGNIFICANTLY FOR TODAY. THIS IS ESPECIALLY
TRUE OVER THE NORTHERN HALF OF THE CWA WHERE TEMPERATURES HAVE YET
TO MAKE IT OUT OF THE 60S. WITH LACK OF SURFACE HEATING...WILL
ALSO REDUCE THE THREAT OF SEVERE THUNDERSTORMS OVER THE MOUNTAINS.
WILL TAKE OUT ENHANCED WORDING FOR THIS AFTERNOON.

---1400Z UPDATE---
SIGNIFICANT CLOUD COVER OVER THE COASTAL PLAIN THIS MORNING NOT
BEING CAPTURED WELL BY THE FORECAST. MODELS ALSO NOT DOING A VERY
GOOD JOB OF HANDLING THIS. THE RUC13 IS PROBABLY DOING THE BEST
JOB OF HANDLING THE CLOUD COVER. NOT SURE IT WILL HAVE MUCH IMPACT
ON HIGH TEMPERATURES FOR TODAY. UPDATED THE FORECAST TO ACCOUNT
FOR THE ADDITIONAL CLOUD COVER.

---1230Z UPDATE---
INTERESTING DAY SHAPING UP FOR NORTHERN NEW ENGLAND. MOST OF THE
MODELS ARE INDICATING A LATE AFTERNOON SEVERE WEATHER EVENT.
HOWEVER...THE LATEST RUN OF THE HRRR IS TRYING TO BRING SOME
CONVECTION INTO THE MOUNTAINS DURING THE LATE MORNING HOURS. WHEN
COMPARED WITH CURRENT RADAR TRENDS...THIS SCENARIO LOOKS PROBABLE.
THIS WILL THEN RAISE THE QUESTION ABOUT HOW WORKED OVER THE
AIRMASS WILL BE AS THE FRONTAL BOUNDARY APPROACHES LATER TODAY. AS
IT LOOKS NOW...WE MAY SEE SOME WEAK CONVECTION OVER THE MOUNTAINS
TODAY BUT THE CELLS WILL BE TOO FAR AWAY FROM THE UPPER LEVEL
SUPPORT TO REACH SEVERE LIMITS. HOWEVER...THERE SHOULD STILL BE
PLENTY OF TIME THIS AFTERNOON FOR THE AIRMASS TO RECOVER ITS
INSTABILITY AS TEMPERATURES RAPIDLY CLIMB. STILL LOOKS LIKE A
CHANCE FOR SOME ISOLATED SEVERE THUNDERSTORMS THIS
AFTERNOON...ESPECIALLY OVER THE MOUNTAINS. WILL UPDATE THE
FORECAST TO ADJUST POPS THIS MORNING AND TWEAK TEMPERATURES A BIT.

COLD FRONT DROPPING SOUTH FROM CANADA TODAY WILL BRING INCREASING
CLOUDS AND A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE
REGION...MAINLY DURING THE AFTERNOON. FAIR AMOUNT OF SHEAR SETTING
UP ACROSS THE REGION EARLY THIS MORNING AND THIS WILL INCREASE
THROUGH EARLY AFTERNOON. ALTHOUGH CAPES WON`T BE TOO IMPRESSIVE
STRONG DYNAMICS MAY SUPPORT A FEW SUPER CELLS ACROSS NORTHERN
SECTIONS DURING THE MID TO LATE AFTERNOON. MAIN THREAT WITH THESE
STORMS WOULD BE DAMAGING WINDS AND LARGE HAIL. WILL INCLUDED
ENHANCED WORDING IN THE ZONES HIGHLIGHTING THESE CONCERNS.

FARTHER SOUTH WILL SEE INCREASING HIGH CLOUDS AND A CHANCE OF
AFTERNOON AND EVENING SHOWERS OR THUNDERSTORMS. TEMPERATURES
SHOULD TAKE A PRETTY GOOD JUMP THIS MORNING AS MIXING GETS GOING.
STRONG SOUTHWEST FLOW AHEAD OF THE FRONT ALREADY PUSHING TEMPS
INTO THE LOWER TO MID 70S IN MONTREAL AT 2 AM. 850 TEMPS GOOD
ENOUGH FOR LOWER 90S IN SOUTHERN NEW HAMPSHIRE INTO SOUTHWEST
MAINE.

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
COLD FRONT WILL PUSH OFFSHORE BY LATE THIS EVENING AND EXPECT
CLEARING SKIES AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST.
LOOKING FOR LOWS NEAR 50 IN THE NORTH AND MID 50S TO LOWER 60S IN
THE SOUTH.

BEAUTIFUL WEATHER FOR SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE
WEST. LOOKING FOR ABUNDANT SUN AND SEASONABLE TEMPERATURES
THROUGHOUT THE FORECAST AREA.

.LONG TERM /SUNDAY THROUGH THURSDAY/...
SFC HIGH PRES BUILDS IN SATURDAY NGT THEN MOVES E ON SUNDAY
PROVIDING FAIR WX...THOUGH THE MODELS DRIVE A SHORT WAVE TROF SE
THRU THE UPR LVL RIDGE OVER NEW ENGLAND ON SUNDAY. THIS WILL BRING
SOME CLOUDINESS AND MAYBE ISOLD SHRA THOUGH NOT MUCH MOISTURE OR
SFC SYSTEM TO SUPPORT MUCH, IF ANY, PRCP ON SUNDAY. THE UPR LVL
AND SFC RIDGE BECOME RE-ESTABLISHED OVER THE NE SUNDAY NGT AND
MONDAY WITH MORE FAIR WX. AN UPR LVL SHORT WAVE TROF MOVES E
MONDAY NGT AND TUESDAY AS MOISTURE INCREASES...GIVING US A CHC OF
PRCP. ANOTHER WEAK UPR LVL IMPULSE AND A SFC FNT CONT THE CHC OF
PRCP TUESDAY NGT INTO WEDNESDAY. HIGH PRES AND FAIR WX RETURNS
LATE WEDNESDAY INTO THURSDAY THOUGH ANOTHER UPR LVL TROF AND SFC
SYSTEM MOVING IN FROM THE W COULD PRODUCE A CHC OF PRCP LATE
THURSDAY.

GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SATURDAY
NGT AND SUNDAY. FOR REST OF THE LONG TERM FCST USED GMOS...EXCEPT
USED A BLEND OF GFS40, HPC GUIDANCE AND MEX MOS GUIDANCE FOR MAX AND
MIN TEMPS.

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...VFR TODAY THROUGH SATURDAY. SOME ISOLATED MVFR/IFR
CEILINGS/VSBY THIS AFTERNOON IN SCATTERED THUNDERSTORMS.

LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...MOSTLY VFR WX THOUGH
SLGT CHC MVFR WITH -SHRA SUNDAY AND CHC OF MVFR WITH SHRA MONDAY
NGT AND TUESDAY.

.MARINE...
SHORT TERM...INCREASING SOUTHWEST TO WEST FLOW WILL BRING GUSTS OF
25 TO 30 KT ON THE WATERS THIS MORNING THROUGH THIS EVENING WITH
SEAS BUILDING 4 TO 6 FT. HAVE ISSUED SCA FROM MID MORNING THROUGH
THIS EVENING.

LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...WEAK FLOW SATURDAY
NGT THRU SUNDAY NGT. SOUTHERLY ONSHORE FLOW INCREASE MONDAY AND
TUESDAY BUT LIKELY TO STAY BELOW SCA LEVELS. SEAS BELOW SCA LEVELS
SATURDAY NGT THRU SUNDAY NGT THEN THEY BUILD WITH THE INCREASING
ONSHORE FLOW MONDAY THRU TUESDAY...POSSIBLY REACHING SCA LEVELS ON
TUESDAY.

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ150-152-
154.

POHL

AREA FORECAST DISCUSSION

NWS GRAY ME

1009 AM EDT FRI AUG 31 2012

.NEAR TERM /THROUGH TONIGHT/...
---1400Z UPDATE---
SIGNIFICANT CLOUD COVER OVER THE COASTAL PLAIN THIS MORNING NOT
BEING CAPTURED WELL BY THE FORECAST. MODELS ALSO NOT DOING A VERY
GOOD JOB OF HANDLING THIS. THE RUC13 IS PROBABLY DOING THE BEST
JOB OF HANDLING THE CLOUD COVER. NOT SURE IT WILL HAVE MUCH IMPACT
ON HIGH TEMPERATURES FOR TODAY. UPDATED THE FORECAST TO ACCOUNT
FOR THE ADDITIONAL CLOUD COVER.

BEAUTIFUL WEATHER FOR SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE
WEST. LOOKING FOR ABUNDANT SUN AND SEASONABLE TEMPERATURES
THROUGHOUT THE FORECAST AREA.

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...VFR TODAY THROUGH SATURDAY. SOME ISOLATED MVFR/IFR
CEILINGS/VSBY THIS AFTERNOON IN SCATTERED THUNDERSTORMS.

LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...MOSTLY VFR WX THOUGH
SLGT CHC MVFR WITH -SHRA SUNDAY AND CHC OF MVFR WITH SHRA MONDAY
NGT AND TUESDAY.

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ150-152-
154.

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...

AREA FORECAST DISCUSSION

NWS GRAY ME

819 AM EDT FRI AUG 31 2012

.NEAR TERM /THROUGH TONIGHT/...
---1230Z UPDATE---
INTERESTING DAY SHAPING UP FOR NORTHERN NEW ENGLAND. MOST OF THE
MODELS ARE INDICATING A LATE AFTERNOON SEVERE WEATHER EVENT.
HOWEVER...THE LATEST RUN OF THE HRRR IS TRYING TO BRING SOME
CONVECTION INTO THE MOUNTAINS DURING THE LATE MORNING HOURS. WHEN
COMPARED WITH CURRENT RADAR TRENDS...THIS SCENARIO LOOKS PROBABLE.
THIS WILL THEN RAISE THE QUESTION ABOUT HOW WORKED OVER THE
AIRMASS WILL BE AS THE FRONTAL BOUNDARY APPROACHES LATER TODAY. AS
IT LOOKS NOW...WE MAY SEE SOME WEAK CONVECTION OVER THE MOUNTAINS
TODAY BUT THE CELLS WILL BE TOO FAR AWAY FROM THE UPPER LEVEL
SUPPORT TO REACH SEVERE LIMITS. HOWEVER...THERE SHOULD STILL BE
PLENTY OF TIME THIS AFTERNOON FOR THE AIRMASS TO RECOVER ITS
INSTABILITY AS TEMPERATURES RAPIDLY CLIMB. STILL LOOKS LIKE A
CHANCE FOR SOME ISOLATED SEVERE THUNDERSTORMS THIS
AFTERNOON...ESPECIALLY OVER THE MOUNTAINS. WILL UPDATE THE
FORECAST TO ADJUST POPS THIS MORNING AND TWEAK TEMPERATURES A BIT.

BEAUTIFUL WEATHER FOR SATURDAY AS HIGH PRESSURE BUILDS IN FROM THE
WEST. LOOKING FOR ABUNDANT SUN AND SEASONABLE TEMPERATURES
THROUGHOUT THE FORECAST AREA.

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...VFR TODAY THROUGH SATURDAY. SOME ISOLATED MVFR/IFR
CEILINGS/VSBY THIS AFTERNOON IN SCATTERED THUNDERSTORMS.

LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...MOSTLY VFR WX THOUGH
SLGT CHC MVFR WITH -SHRA SUNDAY AND CHC OF MVFR WITH SHRA MONDAY
NGT AND TUESDAY.

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ150-152-
154.

POHL

AREA FORECAST DISCUSSION

NWS CARIBOU ME

101 AM EDT FRI AUG 31 2012

.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTH OF MAINE OVERNIGHT THROUGH
FRIDAY...DRAWING A COLD FRONT ACROSS THE REGION FRIDAY. HIGH
PRESSURE WILL BUILD ACROSS THE REGION THROUGH THE WEEKEND.&&

.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE: UPDATED POPS AND WX GRIDS TO MENTION SCT SHWRS
ACROSS ALL OF NRN AROOSTOOK COUNTY (ZONES 1 AND 2) FOR THE
REMAINDER OF THE NGT. ALTHOUGH HRRR RAPID UPDATE MODEL DATA
DOES NOT INDICATE TSTMS CURRENTLY IN THE ST LAWRENCE VLY AREA
OF QB NEAR ALMA AND BAGOTTSVILLE MAKING IT INTO OUR FA BEFORE
DISSIPATING...WE DO MENTION ISOLD TSTMS CAPABLE OF PRODUCING
GUSTY WINDS TIL ABOUT DAYBREAK. MOST OF THIS ACTIVITY SHOULD
MOVE OUT OF NRN AREAS BY 12Z.

WE ALSO WENT AHEAD AND DERIVED THE POP DISTRIBUTION FOR SHWRS/TSTMS
FOR FRI DAY AND EVE...INCLUDING ENHANCED WORDING FOR HAIL AND
CNVCTV WINDS AND QPF WITH TSTMS FRI AFTN INTO ERLY EVE ASSOCIATED
WITH AN ADVANCING COLD FRONT...BUT MORE DETAILS ON THIS WITH THE
NEXT FCST UPDATE.

PREV UPDATE: LOW PRESSURE WILL BEGIN TO TRACK NORTH OF MAINE
OVERNIGHT...WITH HIGH PRESSURE TO THE SOUTH. THE LOW WILL DRAW A
COLD FRONT TOWARD THE REGION LATE TONIGHT. PARTLY/MOSTLY CLOUDY
SKIES WILL EXIST ACROSS NORTHERN AREAS OVERNIGHT ALONG WITH A
CHANCE OF SHOWERS. MOSTLY CLEAR SKIES ARE EXPECTED DOWNEAST
OVERNIGHT. OVERNIGHT LOW TEMPERATURES WILL GENERALLY RANGE FROM
THE UPPER 50S TO THE LOWER 60S ACROSS THE FORECAST AREA. HAVE
UPDATED THE FORECAST TO ADJUST FOR CURRENT CONDITIONS ALONG WITH
EXPECTED OVERNIGHT CLOUD COVER/SHOWER CHANCES/TEMPERATURES. HAVE
SLIGHTLY INCREASED SHOWER CHANCES ACROSS NORTHERN AREAS OVERNIGHT.

ORGNL DISC: THE LOW MOVING NORTH OF MAINE FRIDAY WILL PULL A COLD FRONT
ACROSS THE AREA. FORECAST CAPES AHEAD OF THE FRONT RANGE FROM
AROUND 1500 J/KG ON THE NAM TO 500 J/KG ON THE GFS. THE SHEARING
ENVIRONMENT IS VERY STRONG WITH WINDS INCREASING FROM AROUND 15KT
ON THE SURFACE TO ALMOST 40 KT AT 5000 FT. THE SHEAR COULD MAKE IT
DIFFICULT FOR CONVECTION TO DEVELOP. HOWEVER...CONVECTION THAT
DOES DEVELOP COULD RESULT IN STRONG GUSTY AND POSSIBLY DAMAGING
WINDS DUE TO THE STRONG WINDS ALOFT THAT COULD CARRY MOMENTUM TO
THE SURFACE IN ANY DOWNDRAFTS. THE FRONT WILL REACH THE DOWNEAST
REGION LATE FRIDAY AS COOLER AIR BEGINS TO FILTER INTO THE NORTH.

.SHORT TERM /TONIGHT THROUGH SUNDAY/...
COOLER, DRIER AIR TO MOVE IN FRIDAY NIGHT AS A COLD FRONT PASSES
THROUGH THE AREA FROM NORTHWEST TO SOUTHEAST. WEAK UPPER LEVEL
RIDGE AND A SURFACE HIGH PRESSURE OVERHEAD ON SATURDAY WILL LEAD
TO A VERY PLEASANT DAY. HIGH PRESSURE OVERHEAD SATURDAY NIGHT WILL
ALLOW FOR TEMPERATURES TO DROP EASILY INTO THE 40S FOR MOST AREAS,
WITH SOME 30S IN PROTECTED VALLEYS OF NORTHERN MAINE. A WEAK UPPER
LEVEL TROUGH WILL PASS THROUGH DURING THE DAY SUNDAY, IGNITING
ISOLATED TO SCATTERED SHOWERS MAINLY DURING THE AFTERNOON.

MODELS ARE IN GOOD AGREEMENT FRIDAY NIGHT THROUGH SUNDAY. PRIMARY
CHANGE TO PREVIOUS FORECAST WAS TO INTRODUCE 20 TO 40 PERCENT POPS
FOR SUNDAY.

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE BUILDS IN FOR MONDAY BUT IS QUICKLY REPLACED BY
UPPER LEVEL SOUTHWEST FLOW AND MOIST LOW LEVEL SOUTHERLY FLOW
TUESDAY AND WEDNESDAY. SOME OF THE MOISTURE MOVING INTO THE AREA
WILL BE FROM THE REMNANTS OF ISAAC. A GOOD CHANCE OF SOME RAIN
DURING THIS PERIOD. MODEL AGREEMENT FALLS APART FROM LATE
WEDNESDAY ONWARD ON WHETHER WE DRY OUT OR REMAIN WET. WENT WITH A
MIDDLE OF THE ROAD APPROACH FOR NOW.

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE REGION
OVERNIGHT...THOUGH OCCASIONAL MVFR CONDITIONS COULD OCCUR ACROSS
NORTHERN AREAS LATE. OCCASIONAL MVFR/IFR CONDITIONS COULD OCCUR
WITH ANY SHOWERS AND THUNDERSTORMS FRIDAY. GUSTY WINDS WILL ALSO
OCCUR ACROSS THE REGION FRIDAY...WITH STRONGER WINDS POSSIBLE WITH
ANY THUNDERSTORMS.

SHORT TERM: GENERALLY VFR CONDITIONS EXPECTED FRIDAY NIGHT
THROUGH MONDAY. MVFR CONDITIONS ARE POSSIBLE TUESDAY.

.MARINE...
NEAR TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS OVERNIGHT. SMALL CRAFT ADVISORY LEVEL WINDS/SEAS
ARE THEN POSSIBLE FRIDAY.

SHORT TERM: WINDS WILL SHIFT FROM SOUTHWEST TO NORTH FRIDAY NIGHT
AS A COLD FRONT PASSES THROUGH. WINDS AND SEAS WILL BE AT OR JUST
BELOW SMALL CRAFT LEVELS FRIDAY NIGHT, BUT CONDITIONS CALM DOWN
FOR SATURDAY AND SUNDAY WITH HIGH PRESSURE OVERHEAD.

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.

$$
NEAR TERM...VJN
SHORT TERM...FOISY
LONG TERM...FOISY
AVIATION...VJN
MARINE...VJN/FOISY

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

737 PM EDT SAT SEP 1 2012

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 407 PM EDT SAT SEP 1 2012

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE PACIFIC NW
WITH DOWNSTREAM RIDGE EXTENDING N INTO SCNTRL CANADA. REMNANT OF
ISAAC IS OVER THE MID MISSISSIPPI VALLEY. DOWNSTREAM OF THE RIDGE
AXIS AND WELL N OF ISAAC REMNANT...TRANQUIL WEATHER DOMINATES UPPER
MI THIS AFTN UNDER ABUNDANT SUNSHINE. THE TRANQUIL WEATHER WILL
PERSIST THRU THE SHORT TERM AS THE UPSTREAM RIDGE SHIFTS E...
REACHING THE GREAT LAKES SUN.

AS SFC HIGH OVER LAKE SUPERIOR DRIFTS E TONIGHT...LIGHT RETURN FLOW
WILL GET UNDERWAY...ESPECIALLY W. SHOULD STILL BE A GOOD RADIATIONAL
COOLING NIGHT UNDER MAINLY CLEAR SKIES...THOUGH NOT AS GOOD AS LAST
NIGHT DUE TO DEVELOPING LIGHT RETURN FLOW AND INCREASING COLUMN
MOISTURE. FAVORED THE LOW SIDE OF AVBL GUIDANCE WHICH HAS
TRADITIONAL COLD SPOTS DROPPING TO THE LWR 40S. THERE IS SOME
CONCERN THAT DEVELOPING LOW-LEVEL E TO SE FLOW ACROSS NRN LAKE MI
COULD LEAD TO STRATUS/FOG DEVELOPMENT OVER THE SCNTRL FCST AREA AS
MARINE MODIFIED HIGHER DWPTS ADVECT INLAND/UPSLOPE INTO THE
RADIATIONALLY COOLED BOUNDARY LAYER INLAND. AT THIS TIME...IT
APPEARS SFC WINDS WILL BE BACKED ENOUGH OVER SCNTRL UPPER MI TO
PREVENT MUCH INLAND ADVECTION OF MOISTURE. WILL BE SOMETHING TO
MONITOR OVERNIGHT.

DRY AIR MASS WILL LINGER THRU SUN AFTN...PROVIDING ONE MORE DRY/WARM
EARLY SEPT DAY. PER FCST SOUNDINGS...STRENGTHENING CAP SUN WILL
LIMIT MIXING DEPTH COMPARED TO RECENT DAYS. MIXING TO 850MB YIELDS
MAX TEMPS MOSTLY IN THE LWR 80S AWAY FROM LAKE MODERATION. ALTHOUGH
VERY DRY AIR LINGERS ALOFT (CENTERED AROUND 800MB)...SFC DWPTS
SHOULDN`T FALL AS MUCH AS IN RECENT AFTNS SINCE MIXING WON`T TAP AS
SIGNIFICANTLY INTO THE DRIER ALOFT. STILL...WITH DWPTS FALLING
TOWARD 50F IN THE AFTN...RH WILL BOTTOM OUT AS LOW AS 30-35PCT.
ALTHOUGH PRES GRADIENT WILL BEGIN TO TIGHTEN BTWN DEPARTING SFC HIGH
AND APPROACHING COLD FRONT OVER THE PLAINS...SFC RIDGING EXTENDING
BACK TO UPPER MI WILL HELP TO SLOW THE INCREASE IN WINDS...AND THIS
WILL HELP TO EASE FIRE WX CONCERNS SUN.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 407 PM EDT SAT SEP 1 2012

MUCH OF OUR WEATHER FOR THIS LONG TERM PERIOD WILL BE HEAVILY
INFLUENCED BY THE 500MB LOW CURRENTLY SPINNING ALONG THE BRITISH
COLUMBIA/ALBERTA BORDER...WHICH WILL SET UP HOUSE OVER
ONTARIO/HUDSON BAY/QUEBEC FROM WEDNESDAY THROUGH AT LEAST NEXT
SATURDAY.

SUNDAY NIGHT...
WILL BEGIN SUNDAY NIGHT WITH THE WRAPPED UP SFC LOW SET UP ACROSS N
SASKATCHEWAN...WITH THE COLD FRONT/OCCLUDED FRONT PUSHING SSE
THROUGH C MANITOBA AND DOWN THROUGH THE RED RIVER VALLEY OF THE N.
LIGHT S WINDS WILL BE COMMON...KEEPING TEMPS FROM FALLING INTO THE
LOW 50S...WITH THE WARMEST TEMPS IN THE 60S NEAR THE GREAT LAKES.

MONDAY...
TIMING OF THE COLD FRONT HAS SLOWED DOWN A BIT...NO LONGER OVER W
LAKE SUPERIOR BY 12Z MONDAY...BUT JUST W. THE LOW ITSELF WILL ONLY
BE ABLE TO PUSH TO W CENTRAL MANITOBA WHERE IT WILL BECOME NEARLY
STATIONARY...SLOWLY EDGING TO NE MANITOBA BY 00Z WEDNESDAY.
MEANWHILE ACROSS UPPER MICHIGAN...UNIDIRECTIONAL WINDS AND AFTERNOON
HEATING COMBINED WITH THE WEAKENING COLD FRONT WILL ALLOW FOR SHOWER
AND THUNDERSTORM DEVELOPMENT. THE MAIN THREAT WILL BE STRONG GUSTY
WINDS DURING THE AFTERNOON...AND EARLY EVENING HOURS FAR E. MUCH OF
THE AREA IS IN A SPC SLIGHT RISK AREA FOR DAY 3/MONDAY. ADDED THE
POTENTIAL TO THE HWO...BUT IT LOOKS MODERATE AT THIS TIME...GIVEN
0-6KM BULK SHEAR VALUES AOB 35KTS...WITH HIGHER VALUES REMAINING W
AND S OF THE CWA. WHILE THE OUTPUT FROM THE 12Z GFS IS NOT AS
EXCITED ABOUT THE POTENTIAL...THE NAM DOES HAVE 0-3KM SHR VALUES OF
150-200M2/S2 OVER FAR W UPPER MI BY 18Z...AND OVER MUCH OF W UPPER
MI BY 21Z. THE BRUNT OF THE STORMS/PRECIP SHOULD BE TRACKING E
15-20KTS.

TUESDAY THROUGH WEDNESDAY...
WARMED UP HIGH TEMPS FOR TUESDAY ROUGHLY 5 DEGREES...WITH THE
HIGHEST VALUES S CENTRAL AND E. THIS AREA SHOULD HAVE THE LEAST
CHANCE OF SEEING PRECIP AND LIGHT SSW WINDS. ANOTHER SURGE OF COOLER
AIR WILL BE TO OUR W...WITH THE SECONDARY COLD FRONT SET UP OVER MN
TUESDAY AFTERNOON. IT SHOULD MOVE ACROSS W UPPER MI TUESDAY EVENING.
SPED UP THE EXIT OF TS IN THE GRIDS FOR WEDNESDAY.

THURSDAY THROUGH SATURDAY...
COOL NW FLOW WITH 850MB TEMPS FALLING TO 6-9C...ASSISTED ADDITIONAL
WEAK SHORTWAVES ALOFT...WILL LIKELY RESULT IN SPRINKLES/DRIZZLE
ACROSS THE FAVORED UPSLOPE LOCATIONS NEAR LAKE SUPERIOR AND E. THESE
LOW POP/LOW QFP SHOWERS WILL CONTINUE OFF AND OFF THROUGH FRIDAY AS
850MB TEMPS COOL A COUPLE MORE DEGREES...AND THE MAIN 500MB TROUGH
SINKS ACROSS THE CWA. MODEL GUIDANCE IS IN FAIRLY GOOD SHAPE...WRT
THE 12Z ISSUANCES...THROUGH FRIDAY MORNING. AFTER THAT TIME THE 12Z
GFS EJECTS THE MAIN 500MB LOW THAT HAD BEEN SITTING NEAR JAMES BAY
AT 12Z FRIDAY QUICKLY NORTHEASTWARD. THE ECMWF ON THE OTHER HAND
JUST HAS THE LOW SLOWLY SINK SE TO QUEBEC. EVEN SO...HIGH PRESSURE
SHOULD STILL BE ABLE TO PUSH ACROSS THE UPPER GREAT LAKES
SATURDAY...THE GFS IS JUST A BIT QUICKER. LAKE BREEZES DOMINATING AT
LEAST LAKE MI BY THE EARLY AFTERNOON HOURS. W FLOW MAY BE MORE
STEADY N ACROSS LAKE SUPERIOR.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 736 PM EDT SAT SEP 1 2012

VFR CONDITIONS ARE EXPECTED INTO SUNDAY AS DRY HIGH PRESSURE REMAINS
OVER/NEAR THE UPPER GREAT LAKES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT SAT SEP 1 2012

UNDER SFC HIGH PRES...WINDS ACROSS LAKE SUPERIOR WILL REMAIN LIGHT
TONIGHT...MOSTLY UNDER 15KT. AS THE HIGH SHIFTS TO THE E SUN...E TO
SE WINDS WILL BEGIN TO INCREASE...REACHING UP TO 20KT OVER FAR WRN
LAKE SUPERIOR AND PORTIONS OF CNTRL LAKE SUPERIOR IN THE AFTN. AS A
COLD FRONT APPROACHES SUN NIGHT...SOUTHERLY WINDS MAY GUST AS HIGH
AS 25KT AT HIGHER OBS PLATFORMS...ESPECIALLY OVER THE E HALF OF THE
LAKE. PRES GRADIENT THEN SLACKENS WITH PASSING COLD FRONT MON...
RESULTING IN WINDS DIMINISHING BACK TO UNDER 15KT MON INTO TUE. NEXT
COLD FRONT PASSING WED WILL BRING AN INCREASE IN W TO NW WINDS TO
AROUND 20KT...MAYBE HIGHER...LATER WED INTO THU.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...ROLFSON

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

406 PM EDT FRI AUG 31 2012

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 401 PM EDT FRI AUG 31 2012

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF OVER THE PACIFIC
NW...RIDGING DOWNSTREAM OVER THE NRN PLAINS/SCNTRL CANADA AND A TROF
OVER SE CANADA/NEW ENGLAND. THE UPSTREAM RIDGE IS CURRENTLY GAINING
AMPLITUDE. WITH THE RIDGE CONTINUING TO BUILD THRU SAT AS IT SHIFTS
E TOWARD THE UPPER LAKES...THE SHORT TERM PORTION OF THE FCST WILL
BE TRANQUIL. THERE IS AN AREA OF MID/HIGH CLOUDS OVER THE DAKOTAS...
AND THE CLOUDS HAVE SOME SUPPORT FROM THE RIGHT ENTRANCE OF UPPER
JET ALONG THE U.S./CANADA BORDER THRU THE UPPER LAKES. SINCE THE
UPPER JET SUPPORT BREAKS DOWN TONIGHT...CLOUDS SHOULD TEND TO
DISSIPATE AND PROBABLY WON`T BE MUCH OF A FACTOR HERE. UNDER MAINLY
CLR SKIES...WINDS WILL DROP OFF TO CALM/NEAR CALM AS SFC HIGH PRES
OVER NW MN SETTLES OVER THE UPPER GREAT LAKES TONIGHT. COMBINED
WITH A DRY COLUMN (PRECIPITABLE WATER 50-60PCT OF NORMAL)...TONIGHT
WILL BE A STRONG RADIATIONAL COOLING NIGHT. OPTED TO GO AT OR BLO
THE LOWEST GUIDANCE OVER THE INTERIOR...ESPECIALLY THE W SINCE
WINDS THERE WILL FALL TO CALM AROUND SUNSET. EXPECT MINS AS LOW AS
THE UPPER 30S IN THE TRADITIONAL COLD SPOTS. DIMINISHING SOIL
MOISTURE DUE TO RECENT DRY SPELL WILL ALSO AID COOLING POTENTIAL
TONIGHT. TYPICAL FOR THIS TIME OF YEAR...LENGTHENING NIGHTS AND WARM
WATER IN SWAMPS/STREAMS/RIVERS/LAKES MAY LEAD TO SOME GROUND FOG.

UNDER MOSTLY SUNNY SKIES...THE FIRST DAY OF METEOROLOGICAL AUTUMN
WILL BE A NICE ONE. ALTHOUGH TEMPS WILL BE ABOVE NORMAL...LOW DWPTS
WILL MAKE FOR A COMFORTABLE DAY. MIXING TOWARD 800MB ON FCST
SOUNDINGS YIELDS MAX TEMPS AROUND 80F INTO THE LWR 80S IN THE
INTERIOR. WITH SFC HIGH SETTING UP OVER LAKE SUPERIOR...LAKESIDE
LOCATIONS WILL HOLD TO THE LOW/MID 70S. WEAKER LAKE BREEZE OFF LAKE
MI WILL PROVIDE LIMITED COOLING. AFTN DWPTS WILL LIKELY FALL TOWARD
THE LWR 40S IN THE INTERIOR BASED ON MIXING DEPTH. ALTHOUGH RH WILL
BOTTOM OUT AS LOW AS THE 25-30PCT RANGE...LIGHT WINDS WILL HELP TO
EASE FIRE WX CONCERNS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 401 PM EDT FRI AUG 31 2012

SATURDAY NIGHT...
THE APEX OF THE SFC TO 500MB RIDGE WILL BE NEAR THE CWA AT 00Z
SUNDAY...WITH THE REMNANTS OF ISAAC ACROSS MO. LOOK FOR THE SFC HIGH
TO SHIFT E TO THE ONTARIO/QUEBEC BORDER AND LOWER GREAT LAKES
OVERNIGHT...WITH A WEAK RETURN OF SSE FLOW WITH SOME MOISTENING OF
THE ATMOSPHERE THANKS TO WINDS PUSHING N AROUND WHAT IS LEFT OF
ISAAC. PW VALUES STARTING OFF AROUND 0.5IN EAST /55 PERCENT OF
NORMAL/ JUMPING TO VALUES RIGHT AROUND NORMAL FOR THIS TIME OF YEAR
BY 12Z SUNDAY...OR 0.75 TO 1IN.

SUNDAY THROUGH SUNDAY NIGHT...
SLIGHT SW FLOW BEGINS ALOFT BEGINS SUNDAY...AND BECOMES MORE ZONAL
MONDAY AS THE 500MB LOW TRANSITIONING ACROSS CENTRAL/S CANADA PUSHES
ACROSS SASKATCHEWAN AND MANITOBA. THERE ARE SIGNIFICANT
DISCREPANCIES WRT THE 31/06Z GFS AND 31/00Z ECMWF...WITH THE 31/00Z
CANADIAN LOOKING TO BE A CLOSE BLEND OF THE 2. THE 12Z RUNS OF THE
GFS AND ECMWF ARE MOVING CLOSER TO A SIMILAR SOLUTION WITH THE
CANADIAN TRACKING LOW. THE RESULT WILL BE AN INCREASE IN
MOISTURE...WITH THE SFC LOW OVER N SASKATCHEWAN AT 18Z SUNDAY...AND
THE COLD FRONT EXTENDING THROUGH THE DAKOTAS AND CENTRAL PLAINS.
EXPECT INCREASED S WINDS SUNDAY NIGHT IN ADVANCE OF THE COLD
FRONT...WITH A CHANCE OF TSRA WEST BY DAYBREAK MONDAY.

MONDAY THROUGH TUESDAY...
THE SFC COLD FRONT SET UP OVER FAR W LAKE SUPERIOR AT 12Z MONDAY /OR
EVEN ACROSS THE KEWEENAW PENINUSLA ACCORDING TO THE 31/00Z
ECMWF/...WILL PUSH JUST E OR RIGHT ACROSS THE FAR E END OF THE CWA
BY 00Z TUESDAY. SO FOR MEMORIAL DAY...A CHANCE OF TSRA WILL CONTINUE
TO TRACK E...WITH IMPROVING CONDITIONS W BY EARLY AFTERNOON. I
ATTEMPTED TO KEEP THE BEST CHANCE OF THUNDER RIGHT ALONG AND JUST
AHEAD OF THE FRONT. MONDAY NIGHT STILL LOOKS TO BE MAINLY DRY AS
HIGH PRESSURE PUSHES IN FROM THE SSW...AS TEMPS FALL INTO THE MID
50S INTERIOR W.

TUESDAY NIGHT THROUGH FRIDAY...
UNSETTLED WEATHER AND A RETURN TO NEAR NORMAL TEMPS WILL LIKELY BE
THE NORM FROM TUESDAY NIGHT THROUGH FRIDAY AS A SERIES OF
DISTURBANCES PUSH OVER OR JUST NORTH OF THE CWA. GIVEN THE FCST
DISCREPANCIES FROM THE VARIOUS MODELS...WILL NOT BE TERRIBLY
SPECIFIC WITH TIMING AS LOW PRESSURE SYSTEMS PUSH NEAR OR JUST N OF
LAKE SUPERIOR.

WINDS WEDNESDAY WILL LIKELY BE HIGHER THAN FORECAST. THE MAIN
DILEMMA HERE STEMS FROM AN AVERAGING OF MODEL GUIDANCE
DIRECTIONS...NW OFF THE GFS AND S OFF THE ECMWF. THE 12Z RUNS GIVE
GETTER CONFIDENCE IN A MORE NW FLOW SOLUTION...SIMILAR TO THE 06Z
RUN OF THE GFS. THIS WILL NEED TO BE LOOKED AT A BIT CLOSER OVER THE
NEXT COUPLE OF RUNS...TO MAKE SURE THIS TREND CONTINUES.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 125 PM EDT FRI AUG 31 2012

VFR CONDITIONS WILL BE THE RULE AT KIWD/KCMX/KSAW AS DRY HIGH
PRESSURE BUILDS OVER THE REGION THRU SAT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 401 PM EDT FRI AUG 31 2012

AS SFC HIGH PRES SETTLES OVER LAKE SUPERIOR TONIGHT AND SAT...WINDS
WILL MOSTLY BE UNDER 15KT. AS THE HIGH SHIFTS TO THE E SAT NIGHT/SUN
AND A COLD FRONT APPROACHES FROM THE W...SOUTHEASTERLY WINDS WILL
GRADUALLY INCREASE...REACHING 10-20KT. SOUTHERLY WINDS MAY GUST UP
TO AROUND 25KT SUN NIGHT/EARLY MON JUST AHEAD OF THE FRONT. THE
STRONGER WINDS WILL BE OBSERVED ON THE HIGHER OBS PLATFORMS. PRES
GRADIENT THEN SLACKENS WITH PASSING COLD FRONT MON...RESULTING IN
WINDS DIMINISHING BACK TO UNDER 15KT MON INTO TUE. THE LIGHTER WINDS
WILL THEN PERSIST INTO WED.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...ROLFSON

AREA FORECAST DISCUSSION

NWS GRAND RAPIDS MI

717 AM EDT FRI AUG 31 2012

.SYNOPSIS...
ISSUED AT 352 AM EDT FRI AUG 31 2012
A WEAK COLD FRONT WILL DROP SOUTH THROUGH THE AREA TODAY.
TEMPERATURES AHEAD OF THE FRONT WILL CLIMB WELL INTO THE 80S AND
APPROACH 90 IN SOME LOCATIONS. TEMPERATURES FOR THE WEEKEND INTO
NEXT WEEK WILL REMAIN ABOVE NORMAL. CHANCES FOR RAIN WILL
GENERALLY BE LIMITED TO THE SOUTHERN PORTION OF THE STATE AS THE
TROPICAL SYSTEM MOVES TO THE OHIO VALLEY.

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 352 AM EDT FRI AUG 31 2012

FORECAST CONCERNS ARE SOMEWHAT LIMITED THIS MORNING AND MAINLY
DEAL WITH THE COLD FRONT PASSING THROUGH TODAY AND CHANCES FOR
RAIN AS THE TROPICAL LOW MOVES NORTH.

THE FORECAST HASN/T CHANGED MUCH AND CONFIDENCE IS REASONABLY HIGH
THAT WE/RE NOT GOING TO SEE MUCH PCPN FOR THE NEXT FEW DAYS.

LATEST IR LOOP SHOWS A BAND OF CLOUDS FROM SOUTH DAKOTA NEWD INTO
SRN ONTARIO. THIS MARKS THE WEAK COLD FRONT THAT WILL MOVE SOUTH
TODAY. TEMPS AHEAD OF THE FRONT WILL CLIMB TO NEAR 90 DEGREES
SOUTH OF I-94 THIS AFTERNOON. MODERATE INSTABILITY WILL BE PRESENT
TOO. HOWEVER...DUE TO THE LACK OF APPRECIABLE MOISTURE CONFIDENCE
IS LOW THAT WE/LL SEE ANY RAIN ALONG THE FRONT. CAN/T RULE IT OUT
COMPLETELY BUT CHANCES ARE LOW ENOUGH THAT WE HAVE DRY GRIDS
TODAY...WHICH IS A CONTINUATION OF THE CURRENT FORECAST. HIGH
PRESSURE WILL BUILD INTO THE REGION AND FUNNEL DRY AIR INTO THE
REGION. THIS HIGH WILL KEEP THE TROPICAL SYSTEM FROM MOVING NORTH
INTO THE GREAT LAKES. AS IT FUNNELS DRY AIR SWWD FROM
ONTARIO...WE/LL LIKELY SEE A SHARP PCPN GRADIENT FROM SRN LWR MI
INTO NRN INDIANA. WE/RE NOT GOING TO SEE MUCH IF ANY RAIN FROM
THIS SYSTEM. WE RAIN FALLS IN THE CWA WILL LIKELY BE SOUTH OF I-94
SATURDAY NIGHT INTO SUNDAY.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 352 AM EDT FRI AUG 31 2012

THE PRIMARY WEATHER ISSUES FOR THIS COMING WEEK ARE RELATED TO THE
POTENTIAL FOR CONVECTION WITH THE COLD FRONT MONDAY AND THEN AGAIN
THURSDAY.

IT WOULD NOW SEEMS A STRONG STORM COMING OFF THE KAMCHATKA PENINSULA
MONDAY BECOMES THE DOMINATE UPPER LEVEL WAVE FEATURE IN THE NORTHERN
HEMISPHERE. IT DEVELOPS A DEEP BUT NONE THE LESS PROGRESSIVE UPPER
TROUGH WITH A 160 KNOT JET CORE WHICH IS STILL DIGGING INTO THE WEST
SIDE OF THAT TROUGH TUESDAY MORNING. THAT SYSTEM PICKS UP REMNANT
LOW FROM A FORMER WEST PACIFIC TYPHOON. THIS COMBINED SYSTEM REACHES
THE DATELINE BY WEDNESDAY. THIS OF COURSE BUILDS A LARGE UPPER RIDGE
IN FRONT OF IT. THAT IS OVER THE WEST COAST OF NORTH AMERICA FROM
CALIFORNIA TO CENTRAL ALASKA IN THE WEDNESDAY TIME FRAME. THIS THEN
SETS THE STAGE FOR SOME SIGNIFICANT DOWN STREAM WEATHER CHANGES THAT
IMPACT SOUTHWEST MICHIGAN (THINK FALL LIKE WEATHER). THIS ACTUALLY
HAS BEEN A RATHER STABLE FEATURE OF THE MODELS OVER THE PAST FEW
DAYS. BY THE WAY THIS ALSO GOES ALONG WITH THE MJO PHASE PROGRESSION
(WHICH SUGGESTS WARM INTO MID WEEK HERE THEN COOLER).

MY DISCUSSION FROM YESTERDAY TALKED ABOUT A SYSTEM OFF BRITISH
COLUMBIA COAST POSSIBLY PHASING WITH A SYSTEM NOW OVER WESTERN
ALASKA. ALL OF THAT IS FORCED BY THE SYSTEM FROM NORTHERN RUSSIA
DIGGING THE DEEP TROUGH WEST OF THE DATELINE.

SO WHAT DOES THIS MEAN FOR SOUTHWEST MICHIGAN WEATHER? IT MEANS WE
GET TWO COLD FRONTS THIS WEEK. BOTH OF WHICH MAY HAVE CONVECTION
WITH THEM. THE LEAD SYSTEM TRIES TO COME THROUGH MONDAY BUT THE
TRAILING SYSTEM IS STRONGER AND DEEPER SO IT BOOTS THE LEAD SYSTEM
OUT OF THE WAY. THAT MEANS THE COLD FRONT WILL WEAKEN AS IT COMES
THROUGH AND IN SO DOING WILL NOT BE PULLING DOWN MUCH COOL AIR
BEHIND IT FOR TUESDAY AND WEDNESDAY. EVEN SO WE COULD GET INTO THE
JET ENTRANCE REGION LIFT AREA MONDAY AFTERNOON OR EVENING. THAT
WOULD HELP THE CAUSE FOR A FEW THUNDERSTORMS BUT MOISTURE IS LIMITED
SO I KEPT THE POP LOW FOR THIS EVENT.

THE BETTER EVENT WILL BE LATER IN THE WEEK AS THE SYSTEM FROM
WESTERN ALASKA COMES INTO THE PICTURE. BY THEN THE WESTERN RIDGE
WILL HAVE HAD A CHANCE TO REALLY BUILD WHICH IN TURN DEEPS THE DOWN
STREAM TROUGH OVER THE GREAT LAKES. IT IS AT THIS TIME OUR CHANCE OF
A SIGNIFICANT CONVECTIVE EVENT WOULD BE. GIVEN THE STRENGTH OF THE
UP STREAM SYSTEM DRIVING THIS... I COULD SEE THIS SLOWING DOWN BY 12
TO 24 HOURS THROUGH. SO I HAVE LOW POPS FOR THURSDAY YET BUT I FEEL
STRONGLY THIS SYSTEM LATE IN THE WEEK OVERALL WILL GIVE SOUTHWEST

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 718 AM EDT FRI AUG 31 2012

BREEZY WITH VFR CONDITIONS INTO THIS AFTERNOON. VFR CONDITIONS
EXPECTED TONIGHT.

THE STRONG WINDS... WEST 40 KNOTS ARE SHOWING UP ON OUR VAD WIND
PROFILE THIS MORNING BETWEEN 2000 AND 3000 FT AGL. WINDS ARE
SOUTHWEST 5 TO 15 KNOTS BELOW 10000 FT AGL. SO THE LOW LEVEL WIND
SHEAR WILL CONTINUE UNTIL THE BOUNDARY LAYER MIXES OUT BETWEEN 13Z
AND 15Z. ONCE IT DOES THROUGH SURFACE WINDS WILL BE GUSTY FROM THE
WEST... LIKE 15 KNOTS GUSTING TO 25 KNOTS. WINDS WILL BE STRONGER
OVER FOR THE MORE EASTERN TAF SITES LIKE LANSING.

SKIES SHOULD BE NEARLY CLEAR THROUGH EARLY AFTERNOON EVEN WITH
THE FRONT DROPPING SOUTH INTO THE AREA BY MID AFTERNOON. THE AIR IS
SO DRY ON THE RAP SOUNDINGS THAT THE LCL IS NEAR 12000 FT INTO
LATE MORNING. I WOULD EXPECT SOME HIGH BASED MID CLOUDS BEHIND THE
FRONT TONIGHT SO I BROUGHT IN A MID CLOUD DECK FOR THAT. WINDS
WILL BECOME LIGHT FROM THE NORTH NORTHEAST AT THE SURFACE BEHIND
THE COLD FRONT.

.MARINE...
ISSUED AT 352 AM EDT FRI AUG 31 2012

SCA CONTINUES INTO THE AFTERNOON. WINDS WILL SLOWLY DIMINISH AND
SCA CONDITIONS WILL SUBSIDE LATE IN THE DAY.

.HYDROLOGY...
ISSUED AT 352AM EDT FRI AUG 31 2012
VERY LITTLE RAINFALL EXPECTED OVER THE WEEKEND. A QUARTER INCH OR
LESS POSSIBLE SOUTH OF I-94 THROUGH SUNDAY.

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT UNTIL 3 PM EDT THIS AFTERNOON FOR MIZ037-
043-050-056-064-071.

LM...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR
LMZ844>849.

SYNOPSIS...93
SHORT TERM...93
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...93
MARINE...93

AREA FORECAST DISCUSSION...UPDATED

NWS ST LOUIS MO

927 PM CDT SAT SEP 1 2012

.UPDATE...
ISSUED AT 853 PM CDT SAT SEP 1 2012

POST TROPICAL REMNANT SFC LOW OF ISAAC HAS MOVED NEWD TO JUST
W OF STL THIS EVNG. MOST OF THE CONVECTION AND THE HEAVIER
SHOWERS/SEVERE STORMS HAVE SHIFTED E OR SE OF OUR FORECAST AREA
WITH MAINLY JUST SCATTERED SHOWERS AND AREAS OF RAIN CONTINUING TO
ROTATE AROUND SFC/UPPER LEVEL LOW OVER OUR AREA. THIS TREND SHOULD
CONTINUE AS THE SFC/UPPER LEVEL LOW CONTINUES TO MOVE SLOWLY EWD
WITH THE BEST COVERAGE OF RAIN OVER THE ERN PORTION OF THE
AREA...EAST OF THE MISSISSIPPI RIVER. MAY STILL GET BRIEF HEAVY
DOWNPOURS WITH PRECIPITABLE WATER VALUES OVER 2 INCHES AND DEEP
WARM CLOUD LAYER DEPTHS WITH HIGH FREEZING LEVELS.

GKS

.SHORT TERM...
ISSUED AT 347 PM CDT SAT SEP 1 2012
(TONIGHT AND SUNDAY)

MAIN CONCERN CONTINUES TO BE SEVERE POTENTIAL AND LOCALLY HEAVY
RAINFALL. THIN LINE OF STORMS EXTENDING FROM CENTRAL ILLINOIS
SOUTHWESTWARD INTO SOUTHEAST MISSOURI WILL CONTINUE TO MOVE NORTH
NORTHEAST THE NEXT FEW HOURS. THE RAP IS SHOWING PERSISTENT LOW
LEVEL MOISTURE CONVERGENCE AS A VORT MAX MOVES AROUND THE SOUTH SIDE
OF THE UPPER LOW NOW MEANDERING OVER MISSOURI. OBJECTIVE ANALYSIS
OVER THIS SAME AREA DEPICTS SBCAPES 1000-1500 J/KG WHICH SHOULD
DIMINISH THROUGH THE EVENING. LIKE YESTERDAY...THERE IS LITTLE DEEP
LAYER SHEAR WITH THIS SYSTEM...SO ANY SEVERE WEATHER WILL BE SHORT
LIVED. MAIN CONCERN IS WHERE THE TORNADO WATCH IS IN EFFECT FOR
SHORT LIVED TORNADOES WHERE 0-1KM SRH VALUES ARE CURRENTLY IN THE
200-250 J/KG RANGE.

SEVERE THREAT WILL WANE THROUGH THE EVENING AS THE INSTABILITY
WEAKENS. WILL CONTINUE TO SEE AREAS OF RAIN THIS EVENING INTO THE
OVERNIGHT. WILL BEGIN TO SLOWLY LOWER POPS FROM WEST TO EAST
TONIGHT AS THE UPPER LOW MOVES EAST. THERE MAY BE SOME LOCALLY
HEAVY RAINFALL WITH THE THUNDERSTORMS INTO EARLY EVENING THAT
COULD CAUSE SOME LOCALIZED FLOODING ALONG AREA CREEKS AND LOW
LYING AREAS. ADDITIONAL RAINFALL TOTALS WILL RANGE FROM A COUPLE
OF TENTHS OVER CENTRAL MISSOURI TO OVER AN INCH OVER SOUTH CENTRAL
ILLINOIS.

BRITT

.LONG TERM...
ISSUED AT 347 PM CDT SAT SEP 1 2012
(SUNDAY NIGHT THROUGH NEXT SATURDAY)

FOLLOWED THE GFS WHICH HAS THE UPPER LOW CONTINUING TO MOVE EAST ON
SUNDAY AND SUNDAY NIGHT. STILL HAVE CHANCE OR LIKELY POPS GOING
SUNDAY WITH CHANCE POPS OVER THE SOUTHEAST HALF THE CWA ON SUNDAY
EVENING. THEREAFTER...STILL LOOKS FAIRLY ACTIVE FOR EARLY
SEPTEMBER. GLOBAL MODELS ARE SHOWING ZONAL FLOW OVER THE NORTHERN
HALF OF THE NATION WHICH WILL BRING A SHORTWAVE ACROSS THE AREA
TUESDAY INTO WEDNESDAY. THERE IS SOME DIFFERENCES BETWEEN THE
GFS/ECMWF LATER IN THE WEEK WITH HOW QUICKLY A TROUGH WILL DIG INTO
THE CENTRAL U.S.. FOR NOW WILL HAVE A CHANCE OF SHOWERS/
THUNDERSTORMS GOING LATE WEEK INTO EARLY NEXT WEEKEND.

BRITT

.AVIATION...
ISSUED AT 719 PM CDT SAT SEP 1 2012

REMAINS OF POST TROPICAL REMANT LOW OF ISSAC IS CENTERED ABOUT 25
MILES SOUTHWEST OF KLSX. SMALL NEW CONVECTIVE CELLS CONTINUE TO
DEVELOP ALONG THE EASTERN FLANK OF THE LOW CENTER MOVING TOWARDS
ST. LOUIS METRO AREA. OTHERWISE THE MAIN CONVECTIVE BAND OF
SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE ACROSS EAST CENTRAL
THROUGH SOUTHERN ILLINOIS AND WESTER KENTUCKY. THE CENTER OF THE
LOW WILL CONTINUE TO MOVE SOUTH THEN EAST OF ST. LOUIS AND SHOULD
BE LOCATED OVER SOUTH CENTRAL ILLINOIS BY 1200 UTC SUNDAY.

SPECIFICS FOR KSTL...WINDS WILL BE LIGHT EASTERLY THROUGH 0200 UTC
THEN BECOME NORTH NORTHEAST 10 TO 12 KTS AFTER 0300-0400 UTC TIME
FRAME. LOWER CIGS WILL MOVE INTO STL AREA AFTER 0400 UTC AND
REMAIN THROUGH SUNDAY MORNING. SOME BREAKS CAN BE EXPECTED AFTER
1500 UTC SCATTERED TO BROKEN AREAS OF SHOWERS AND LOW CIGS CAN BE
EXPECTED DURING THE DAY ON SUNDAY OVER STL AREA AS LOW-LEVEL
MOISTURE CONTINUES TO WRAP AROUND THE LOW CENTER.

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

WFO LSX

AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

747 PM CDT SAT SEP 1 2012

.SHORT TERM...
ISSUED AT 347 PM CDT SAT SEP 1 2012
(TONIGHT AND SUNDAY)

BRITT

.LONG TERM...
ISSUED AT 347 PM CDT SAT SEP 1 2012
(SUNDAY NIGHT THROUGH NEXT SATURDAY)

BRITT

.AVIATION...
ISSUED AT 719 PM CDT SAT SEP 1 2012

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

WFO LSX

AREA FORECAST DISCUSSION

NWS NORTH PLATTE NE

1208 AM CDT FRI AUG 31 2012

.AVIATION...

VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH FRIDAY EVENING.

NO TSTMS ARE FORECAST. SOUTH WINDS DEVELOP FRIDAY IN RESPONSE TO LOW
PRESSURE DEVELOPING ACROSS THE NRN HIGH PLAINS.

.PREV DISCUSSION... /ISSUED 908 PM CDT THU AUG 30 2012/

UPDATE...

DISCUSSION...
WINDS HAVE DECREASED WELL BELOW 25 MPH AND RELATIVE HUMIDITY HAS
RECOVERED TO OVER 20 PERCENT IN MOST AREAS. THE RED FLAG WARNING
HAS BEEN CANCELLED. A FIRE WEATHER WATCH CONTINUES FOR FRIDAY.

PREV DISCUSSION... /ISSUED 350 PM CDT THU AUG 30 2012/

SYNOPSIS...
SURFACE ANALYSIS THIS AFTERNOON...AS A COLD FRONT EXTENDING FROM
AROUND LEWELLEN...TO ARTHUR...TO DUNNING...TO EWING. NORTH OF THIS
FEATURE...TEMPS RANGE FROM 80 AT VALENTINE...TO 94 AT O`NEILL. SOUTH
OF THE FRONT...TEMPS WERE AROUND 100 DEGREES WITH RELATIVE
HUMIDITIES RANGING FROM 5 TO 15 PERCENT. A MAJOR FIRE WAS BURNING
ACROSS NORTHWESTERN SHERIDAN COUNTY THIS AFTERNOON AT THE METCALF
STATE WILDLIFE MANAGEMENT AREA. EVACUATION ORDERS HAVE BEEN GIVEN
FOR THIS AREA OF SHERIDAN COUNTY. ADDITIONAL DETAILS ARE IN
OMAEVILBF.

ALOFT AT H5...RIDGING HAS BEGUN TO TRANSITION EAST THIS MORNING...AS
A TROUGH OF LOW PRESSURE BUILDS ALONG THE PACIFIC NW COAST. AT 12Z
THIS MORNING...ISSAC WAS LOCATED NORTHWEST OF BATON ROUGE LA.

DISCUSSION...

SHORT RANGE...TONIGHT THROUGH SUNDAY...MAIN FORECAST CHALLENGE IS
TEMPERATURES AND FIRE WEATHER CONCERNS OVER THE NEXT 24 TO 36 HRS.
FOR TONIGHT...THE LATEST NAM SOLN STALLS THE COLD FRONT ALONG
HIGHWAYS 92 AND 91 THIS EVENING...WHILE THE HIGH RES RUC PUSHES THIS
FEATURE THROUGH NORTH PLATTE TO JUST SOUTH OF INTERSTATE 80. EVEN
WITH A MORE AGGRESSIVE FRONTAL PUSH DEPICTED BY THE HI RES
RUC...LOCATIONS AHEAD OF THE FRONT HAVE ALREADY TORCHED OUT THIS
AFTERNOON WITH WIDESPREAD HIGHS WELL ABOVE THE CENTURY MARK AND
RELATIVE HUMIDITIES AS LOW AS 5 PERCENT. AS SURFACE HIGH PRESSURE
BUILDS EAST OF THE DAKOTAS OVERNIGHT...SRLY WINDS WILL BEGIN TO LIFT
THE FRONT NORTH ON FRIDAY CONTINUES TO BE PROBLEMATIC AS THE LATEST
NEAR TERM MODEL SOLUTIONS ARE MUCH FARTHER SOUTH WITH THIS FEATURE
COMPARED TO YESTERDAY`S RUNS. THE LATEST MODEL RUNS PUSH THE FRONT
NORTH TO THE BLACK HILLS AND NERN NEBRASKA FRIDAY MORNING...WHICH
WILL LEAD TO ANOTHER TORCH OUT ACROSS A LARGE PORTION OF THE
FORECAST AREA ON FRIDAY. WENT AHEAD AND TRENDED TEMPS UPWARD FOR
FRIDAY...WHICH YIELDED HIGHS RANGING FROM THE MID 90S TO LOWER 100S.
VERY DRY BOUNDARY LAYER AIR WILL REMAIN IN PLACE...WHICH WILL LEAD
TO CRITICAL OR NEAR CRITICAL MINIMUM RH VALS FOR TOMORROW AFTERNOON.
THE ONE QUESTION NOW IS THE WINDS AND HOW HARD THEY WILL BLOW
FRIDAY. ATTM...THE BEST THREAT FOR GUSTS TO 25 MPH...IS ALONG AND
WEST OF HIGHWAY 83 FROM VALENTINE TO NORTH PLATTE. FURTHER
EAST...SLIGHTLY LIGHTER WINDS...WITH AN EASTERLY COMPONENT ARE
EXPECTED WHICH WILL ALSO BEGIN TO LIFT SOME BL MOISTURE FROM THE
REMNANTS OF ISAAC. WITH SOME DOUBT AS TO WHERE THE FRONT WILL STALL
TOMORROW...WILL HOIST A FIRE WEATHER WATCH FOR TOMORROW AFTERNOON
FOR ALL ZONES WITH THE EXCEPTION OF ZONE 209 WHERE WINDS WILL BE
LIGHTER.

FOR SATURDAY AND SUNDAY...FIRE THREAT IS EXPECTED TO DIMINISH
SOMEWHAT FOR SATURDAY IN THE CENTRAL AND THE EAST. IT WILL BE WARM ONCE
AGAIN WITH HIGHS IN THE LOWER TO MIDDLE 90S. HOWEVER...LOW LEVEL
MOISTURE WILL INCREASE FRIDAY NIGHT AS ISAAC LIFTS INTO MISSOURI.
FCSTED DEW POINTS SATURDAY AFTERNOON WILL RANGE FROM THE MID 40S IN
THE WEST TO AROUND 60 IN THE EAST. WITH THE EXCEPTION OF THE
WEST...SRLY WINDS WILL GENERALLY BE UNDER 15 MPH. EXTREME OR NEAR
CRITICAL FIRE DANGER LOOKS POSSIBLE IN THE WEST AND WILL CONTINUE TO
MONITOR. BY SUNDAY...A SURFACE TROUGH OF LOW PRESSURE WILL APPROACH
WESTERN AND NORTH CENTRAL NEBRASKA. EAST OF THIS FEATURE...HOT
TEMPERATURES IN THE 90S ARE LIKELY. ATTM ENOUGH RESIDUAL MOISTURE
WILL BE IN PLACE...WHICH SHOULD KEEP CRITICAL FIRE CONDS IN CHECK.
SOME WESTERN AREAS MAY BE UNDER THE GUN FOR FIRE DANGER
SUNDAY...WITH HIGHS IN THE 90S AND MINIMUM DEW POINTS IN THE LOWER
TO MID 40S.

LONG RANGE...SUNDAY NIGHT THROUGH THURSDAY...SUNDAY NIGHT THROUGH
THURSDAY. UPPER LEVEL RIDGE IS FORECASTED TO TRANSITION BACK TO THE
DESERT SOUTHWEST DURING THE PERIOD...WITH THE UPPER FLOW OVER OUR
AREA BECOMING WEST TO NORTHWEST ALOFT. SOME INCREASE IN MOISTURE IS
EXPECTED BOTH AT THE SFC AND ALOFT...AND AT LEAST A SLIGHT CHANCE
FOR SHOWERS AND THUNDERSTORMS ARE ANTICIPATED MONDAY THROUGH
WEDNESDAY AS A SERIES OF DISTURBANCES EMBEDDED WITHIN THE FLOW CROSS
THE AREA. TEMPERATURE WISE...AN OVERALL COOLING TREND BACK TO NEAR
NORMAL IS EXPECTED. HIGHS WILL RANGE FROM THE UPPER 80S MONDAY AND
TUESDAY...COOLING TO THE UPPER 70S TO MID 80S WEDNESDAY AND
THURSDAY.

FIRE WEATHER...

A LARGE FIRE IS ONGOING ACROSS NORTHWESTERN SHERIDAN COUNTY AND AN
EVACUATION ORDER HAS BEEN GIVEN FOR METCALF STATE WILDLIFE
MANAGEMENT AREA. SEE OMAEVILBF FOR DETAILS. RH WILL BEGIN TO RECOVER
TO 20 TO 30 PERCENT IN SOUTHERN AREAS AROUND 03Z THIS EVENING...SO
THE ONGOING RED FLAG WARNING WILL CONTINUE FOR ALL ZONES EXCEPT
NEZ208. ALL LOCATIONS IN THIS ZONE ARE NOW NORTH OF THE COLD
FRONT...WITH RH`S CURRENTLY RUNNING FROM 30 TO 40 PERCENT.

OVERNIGHT TONIGHT...THE COLD FRONT WILL LIFT NORTH AS A WARM
FRONT...AS HIGH PRESSURE LIFTS INTO MINNESOTA. FOR FRIDAY...A WARM
FRONT WILL BE ANCHORED FROM THE BLACK HILLS INTO NERN
NEBRASKA...WHICH WILL ALLOW THE HEAT TO BUILD NORTH INTO WESTERN AND
NORTH CENTRAL NEBRASKA FRIDAY AFTERNOON. GUSTY SRLY WINDS WILL
DEVELOP ACROSS THE CENTRAL AND WESTERN SAND HILLS...AS WELL AS THE
EASTERN NEBRASKA PANHANDLE AND SOUTHWESTERN NEBRASKA FRIDAY
AFTERNOON AND MAY GUST AS HIGH AS 25 MPH. WITH FCST DEW POINTS IN
THE 30S AND LOWER 40S FRIDAY AFTERNOON...MINIMUM RH`S OF AROUND 15
PERCENT ARE POSSIBLE. WILL BE HOISTING A FIRE WEATHER WATCH FOR
FRIDAY AFTERNOON AND EVENING FOR ALL ZONES EXCEPT 209 FOR THE
POSSIBILITY OF CRITICAL FIRE DANGER FRIDAY AFTERNOON.

.LBF WATCHES/WARNINGS/ADVISORIES...FIRE WEATHER WATCH FROM 10 AM CDT /9 AM MDT/ THIS MORNING
THROUGH THIS EVENING FOR NEZ204-206-208-210-219.

SHORT TERM/EXTENDED...BUTTLER/TAYLOR
AVIATION...ROBERG

AREA FORECAST DISCUSSION

NWS BUFFALO NY

355 PM EDT FRI AUG 31 2012

.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH ACROSS THE AREA OVERNIGHT WITH NO MORE
THAN ISOLATED SHOWERS AND THUNDERSTORMS ACROSS NORTHERN NEW YORK.
HIGH PRESSURE WILL RETURN BEHIND THE FRONT WITH MORE SEASONABLE
TEMPERATURES FOR THE WEEKEND. THE NEXT CHANCE FOR RAIN WILL BE EARLY
NEXT WEEK WHEN THE REMNANTS OF ISSAC WILL POTENTIALLY IMPACT THE
REGION.

.NEAR TERM /THROUGH SATURDAY/...
SURFACE ANALYSIS ALONG WITH RADAR AND SATELLITE IMAGERY REVEAL A
COLD FRONT ORIENTED EAST TO WEST ACROSS SOUTHERN QUEBEC AND ONTARIO
PROVINCES JUST NORTH OF OTTAWA AT 19Z. KTYX NWS DOPPLER AND THE
CANADIAN RADAR NEAR MONTREAL SHOW A BAND OF THUNDERSTORMS ORIENTED
ALONG THE FRONT WITH ANOTHER AREA OF THUNDERSTORMS BETWEEN MONTREAL
QUEBEC AND MASSENA NEW YORK. A TIGHT PRESSURE GRADIENT EXISTS ACROSS
NEW YORK SOUTH OF THE FRONT AS IT SLOWLY SQUEEZES SOUTH TOWARD A
SURFACE HIGH OVER THE MID ATLANTIC. THIS IS CREATING GUSTY SOUTHWEST
WINDS ACROSS THE FORECAST AREA AVERAGING 20 TO 30 MPH.

HIGH RESOLUTION MODEL DATA INCLUDING THE 17Z HRRR AND LATEST NMM/ARW
WRF RUNS INDICATE INCREASING CONVECTION FORMING AHEAD OF AND ALONG
THE FRONT INTO THE EARLY EVENING AS IT PRESSES FURTHER SOUTHWARD
TOWARD NORTHERN NY. THE BIG QUESTION IS WHETHER ENOUGH LOW LEVEL
MOISTURE WILL BE AVAILABLE ACROSS NORTHERN NY AND IF SURFACE
INSTABILITY CAN OVERCOME THE MID LEVEL HEAT RIDGE BUILDING NORTH
ACROSS CENTRAL NEW YORK. WHILE SURFACE MOISTURE IS LIMITED WITH
DEWPOINT DEPRESSIONS OF AROUND 15F...SOME MID LEVEL MOISTURE IS
AVAILABLE...SPC MESOANALYSIS DATA SHOWING 1.5 TO 1.8 INCHES OF
PRECIPITABLE WATER EAST OF LAKE ONTARIO. MESOANALYSIS ALSO REVEALS A
CAP IN PLACE ACROSS THE FORECAST AREA WITH THE ONLY UNCAPPED AREA
WITH SOME CAPE BEING NEAR OTTAWA. WIND SHEAR HOWEVER IS HIGH WITH
MESOANALYSIS INDICATING 0-6 KM SHEAR RUNNING GREATER THAN 50 KTS. IF
SIGNIFICANT STORM UPDRAFTS CAN DEVELOP SOUTH INTO THE EASTERN LAKE
ONTARIO REGION IT APPEARS THAT DAMAGING WINDS WOULD BE THE MAIN
SEVERE WEATHER THREAT WITH THE STRONGEST CELLS. SPC HAS INCLUDED
PARTS OF THE EASTERN LAKE ONTARIO REGION IN A SLIGHT RISK FOR SEVERE
STORMS.

TONIGHT...WIND GUSTS ARE FORECAST TO FALL OFF NEAR SUNSET WITH
SUSTAINED WINDS OF AROUND 10 MPH FINALLY LOWERING WHEN THE SURFACE
FRONT SHIFTS SOUTH OF THE AREA. COOLER TEMPERATURES WILL ADVECT INTO
THE REGION WITH MAINLY CLEAR SKIES. OVERNIGHT LOWS FORECASTED A BIT
WARMER BASED ON 12Z MODEL GUIDANCE AND HIGH TEMPS REACHED TODAY
FALLING INTO THE 60S. NORTHERLY FLOW SETTING UP BEHIND THE FRONT MAY
HOLD THE LAKE PLAIN AREAS A LITTLE WARMER. MOS GUIDANCE AND BUFKIT
PROFILES INDICATE PATCHY FOG ALSO POSSIBLE TONIGHT MOST LIKELY IN
SHELTERED AREAS AFTER THE WINDS FALL OFF. CLEAR SKIES SHOULD PROVIDE
GREAT RADIATIONAL COOLING BUT WINDS WILL BE THE QUESTION.

ON SATURDAY HIGH PRESSURE OVER MINNESOTA THIS EVENING WILL SHIFT
EASTWARD AND BUILD IN BEHIND THE FRONT. EXPECT MAINLY CLEAR SKIES
WITH LIGHT NORTHERLY WINDS AND SEASONABLE TEMPERATURES RUNNING IN
THE UPPER 70S TO LOW 80S...A FINE LATE SUMMER DAY!

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
HIGH PRESSURE ACROSS THE UPPER LAKES SATURDAY EVENING WILL SHIFT
TO NORTHERN NEW ENGLAND THROUGH SUNDAY NIGHT. IT STILL APPEARS THIS
HIGH WILL KEEP MOISTURE ASSOCIATED WITH THE REMNANTS OF ISAAC TO OUR
SOUTH AND WEST.

EXPECT SUNDAY TO BE A QUITE PLEASANT DAY ACROSS WESTERN NEW
YORK...WITH SEASONABLE TEMPERATURES IN THE UPPER 70S AND LOWER 80S.
THERE WILL BE QUITE A BIT OF SUNSHINE ACROSS MOST OF THE
REGION...WITH CLOUDS A BIT MORE PREVALENT IN THE SOUTHERN TIER. THERE
MAY BE SCATTERED SHOWERS TO OUR SOUTH...BUT A PRETTY STRONG MODEL
CONSENSUS KEEPS THIS OUT OF OUR REGION ON THE STRENGTH OF THE HIGH
POSITIONED TO OUR NORTH.

.LONG TERM /MONDAY THROUGH FRIDAY/...
12Z MODEL CONSENSUS HAS SLOWED A BIT WITH THE APPROACH OF MOISTURE
FROM THE TROPICAL REMNANTS OF ISAAC. PART OF THIS IS THAT MODEL
GUIDANCE HAS BEEN TRENDING TOWARD A WEAKER SHORTWAVE EARLY NEXT
WEEK...WHICH ALSO SLOWS AND WEAKENS THE APPROACH OF AN ASSOCIATED
FRONTAL BOUNDARY. WHILE THE MAJORITY OF MODELS (GFS/EUROPEAN) BRING
SHOWERS AND THUNDERSTORMS INTO WESTERN NEW YORK ON MONDAY...THE GGEM
IS A LARGELY DRY FORECAST.

WITH THIS TREND IN MIND...EXPECT THE STEADIEST RAINS TO COME DURING
THE LATTER HALF OF MONDAY NIGHT THROUGH TUESDAY MORNING...WITH THIS
AXIS LIKELY TO SHIFT INTO EASTERN PORTIONS OF THE CWA TUESDAY
AFTERNOON. OUTSIDE OF THE SLIGHTLY SLOWER TIMING...OUR EXPECTATION
OF RAINFALL AVERAGING AROUND AN INCH REMAINS THE SAME. MODEL
GUIDANCE HAS BEEN INCONSISTENT ON QPF...WITH THE 12Z GFS IN
PARTICULAR LIKELY OVERDONE IN A CONVECTIVE BULLSEYE IN WESTERN
PORTIONS OF THE SOUTHERN TIER. THE GGEM/EUROPEAN ARE BOTH MUCH MORE
IN LINE WITH PREVIOUS CONSENSUS...THOUGH IT SHOULD BE NOTED THAT
LOCALLY HIGHER...AND LOWER...AMOUNTS ARE EXPECTED. IT IS SIMPLY TOO
FAR OFF TO PIN SPECIFICS DOWN. WHILE RAINFALL AMOUNTS WILL VARY...AN
INCH OF RAIN WOULD BE BENEFICIAL FOR AREAS IMPACTED BY THE DROUGHT.
THE POTENTIAL FOR FLOODING REMAIN LOW FOR WESTERN NEW YORK...WITH
THE ONLY REAL THREAT COMING FROM LOCALIZED OR SLOW MOVING CONVECTIVE
CELLS.

THE SHORTWAVE AND ASSOCIATED FRONTAL BOUNDARY WILL EXIT TO THE EAST
TUESDAY NIGHT...WITH THE REGION LIKELY TO END UP BETWEEN SYSTEMS
WEDNESDAY. THEN A DEEPER SHORTWAVE WILL APPROACH...WITH A BLEND OF
THE GFS/EUROPEAN BRINGING THIS ACROSS WEDNESDAY NIGHT OR THURSDAY.
THIS FRONT SUPPORTS CHANCE POPS FOR NOW.

BOTH THE 12Z GFS/EUROPEAN EXIT THIS FRONT TO THE EAST...WITH DRY
WEATHER LIKELY FOR FRIDAY. THE GFS IS QUITE A BIT COOLER THAN THE
EUROPEAN...WITH OUR FORECAST A BLEND BETWEEN THE TWO.

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
MAINLY VFR CONDITIONS EXPECTED THROUGH THE 18Z TAF CYCLE EXCEPT FOR
SOME FOG DEVELOPING ACROSS THE SOUTHERN TIER WHICH MAY IMPACT KJHW.
THIS EVENING A COLD FRONT LOCATED JUST NORTH OF THE NY/CANADIAN
BORDER WILL DRIFT SOUTH ACROSS THE STATE. ONLY ISOLATED SHOWERS OR
THUNDERSTORMS COULD DEVELOP ACROSS NORTHERN NEW YORK EARLY THIS
AHEAD OF THE FRONT.

WINDS WILL BE THE MAIN ISSUE EARLY THIS EVENING WITH GUSTS STILL
RUNNING 25 TO 35 KTS AT 19Z. HIGHEST WIND ISSUES WILL BE ACROSS THE
NIAGARA FRONTIER AS THE SOUTHWEST WINDS FUNNEL ALONG LAKE ERIE. WIND
GUSTS WILL FALL OFF NEAR SUNSET WITH THE END OF MIXING. SUSTAINED
WINDS WILL THEN FALL OFF INTO THE LATE EVENING AFTER THE COLD FRONT
DROPS SOUTH.

LATE TONIGHT MOS AND LAMP GUIDANCE INDICATE POTENTIAL FOR FOG AT
KJHW. WHILE GUIDANCE IS GOING AS LOW AS LIFR OPTED TO KEEP VIS DOWN
TO ONLY 2SM FOR NOW. THE ISSUE WHICH MAY PREVENT THIS WOULD BE WINDS
REMAINING TOO HIGH LATE TONIGHT. VFR SATURDAY UNDER HIGH PRESSURE.

OUTLOOK...
SATURDAY THROUGH SUNDAY...VFR.
MONDAY...LIKELY RAIN SHOWERS DETERIORATING TO MVFR.
MONDAY NIGHT AND TUESDAY...MVFR/IFR IN RAIN SHOWERS LIKELY MONDAY
NIGHT...AND POSSIBLY ON TUESDAY.

.MARINE...
A COLD FRONT DROPPING SOUTHWARD FROM CANADA HAS TIGHTEN THE PRESSURE
GRADIENT OVER THE LOWER GREAT LAKES REGION THIS AFTERNOON AND
EVENING AS IT RUNS INTO A HIGH PRESSURE SYSTEM OVER THE
MID-ATLANTIC. SOUTHWEST WINDS AND WAVES HAVE REACHED SMALL CRAFT
ADVISORY CRITERIA TODAY AHEAD OF THE FRONT. SMALL CRAFTS REMAIN IN
EFFECT FOR ALL MARINE ZONES EXCEPT THE LOWER NIAGARA AND ST.
LAWRENCE RIVER. BEHIND THE FRONT...WINDS WILL SHIFT TO LIGHT
NORTHERLY AND WAVE HEIGHTS WILL EVENTUALLY SUBSIDE OVER THE LAKES.
HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION SATURDAY...RESULTING
IN FINE BOATING WEATHER FOR THE WEEKEND.

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ020.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
LOZ042-043.
SMALL CRAFT ADVISORY UNTIL 1 AM EDT SATURDAY FOR LOZ045.
SMALL CRAFT ADVISORY UNTIL 3 AM EDT SATURDAY FOR LOZ044.

SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...APFFEL
LONG TERM...APFFEL
AVIATION...SMITH
MARINE...APFFEL/SMITH

AREA FORECAST DISCUSSION

NWS NEWPORT/MOREHEAD CITY NC

954 PM EDT SAT SEP 1 2012

.SYNOPSIS...
A WEAK COLD FRONT WILL DROP SOUTH INTO THE NORTHERN SECTIONS LATE
THIS AFTERNOON THEN STALL OVER THE REGION THROUGH EARLY NEXT
WEEK. A TROUGH OF LOW PRESSURE WILL DEVELOP TO THE WEST MID WEEK.
A STRONGER COLD FRONT WILL PUSH THROUGH THE AREA LATE IN THE WEEK.

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 950 PM SATURDAY...LATEST RAP NOT SHOWING ANY PRECIPITATION
ACROSS THE AREA OVERNIGHT. THERE HAVE BEEN SOME LIGHT RETURNS ON
RADAR OVER OUR NORTHWESTERN COUNTIES...BUT ARE LIKELY NOT REACHING
THE GROUND. SURFACE OBS DID SHOW SOME LIGHT PRECIPITATION BACK
WEST OF RALEIGH THIS EVENING. WILL TRIM BACK AREA OF SLIGHT CHC
POPS TO JUST THE WESTERN SECTIONS OVERNIGHT AND WILL REMOVE
MENTION OF THUNDER. ANOTHER WARM MUGGY NIGHT AS MINIMUM TEMPERATURES
ARE LIKELY TO REMAIN AT OR ABOVE 75 DEGREES IN MOST AREAS.

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
UPPER RIDGE RE-BUILDS INTO THE AREA SUNDAY FROM OFF THE SE COAST.
THIS SHUD LIMIT PCPN CHANCES EARLY ON BUT WITH INCREASING
INSTABILITY (1500-2000 J/KG) AND WEAK SHORT WAVE ENERGY RIDING
OVER THE UPPER RIDGE...CONVECTION WILL FOCUS ON THE LINGERING SFC
TROF MAINLY OVER INLAND AREAS DURING THE AFTN. MOS GUIDANCE TEMPS
ARE VERY WARM TOMORROW SUGGESTING HIGHS BACK INTO THE LOW TO MID
90S INLAND BUT EXPECT THAT WITH LINGERING (BUT THINNING) CLOUD
COVER DURING THE MORNING AND SCTD AFTN PCPN...MOST HIGHS SHUD TOP
OUT IN THE UPPER 80S TO AROUND 90 WITH MID 80S AT THE BEACHES.
AFTN PCPN WILL HAVE THE POTENTIAL TO BE HEAVY WITH PRECIP WATERS
IN EXCESS OF 2 INCHES.

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
AS OF 330 PM SAT...RAIN CHANCES WILL BEGIN THE LONG TERM
PERIOD...FOLLOWED BY MAINLY DRY CONDITIONS MID WEEK BEFORE ANOTHER
CHANCE FOR SHOWERS/STORMS BY THURSDAY AS A COLD FRONT APPROACHES.
TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD.

MODELS STILL INDICATING INC SOUTHERLY LOW LEVEL MOISTURE FLOW ACROSS
THE AREA THROUGH MONDAY...WHILE UPR FLOW IS NORTHWESTERLY
TRANSPORTING REMNANT MOISTURE FROM ISAACS GHOST. THIS WILL BRING
AN INC IN PRECIP COVERAGE ON MONDAY AFTERNOON...ESP WESTERN AND
NORTHERN PORTIONS...WHERE LIFT IS GREATEST AND LOW LEVEL
CONVERGENCE IS MAXIMIZED. NOT QUITE CONFIDENT ENOUGH TO INCLUDE
LIKELY POPS...AND LEFT IN CHANCE/SCT POPS WITH BEST CHANCES
OCCURRING AFTER NOON. ECMWF MOS IS INDICATING 50 PERCENT
POPS...WHILE MAV MOS IS A BIT DRIER...30-40 PERCENT. MOST SREF
ENSEMBLE MEMBERS FCSTING MEASURABLE RAINFALL FOR THE INLAND
AREAS.

TEMPERATURES FOR MON AND TUE SHOULD GENERALLY TOP OUT AROUND 90
FOR MOST AREAS AS LOW LEVEL THICKNESSES REMAIN IN THE ~1415 RANGE.
DISCOUNTED BIAS CORRECTED GRIDS FOR MAX T`S...AS THEY SEEM TO BE
TOO COOL GIVEN THE THICKNESS VALUES FCST. ECM/MEX GUIDANCE IS MORE
REASONABLE. TEMPS MODERATE THUR THROUGH THE WEEKEND AS A COOL
FRONT ENTERS THE AREA.

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH SATURDAY AFTERNOON/...
AS OF 630 PM SATURDAY...BIG QUESTION REGARDING THE AVIATION
FORECAST TONIGHT CONCERNS THE EXTENT OF DEBRIS CIRRUS THAT WILL
LIMIT FOG FORMATION. ALL OF THE NUMERICAL GUIDANCE INDICATES LOWER
VSBYS IN FOG TOWARD MORNING. GIVEN THE UNCERTAINTY...WILL REMAIN
CONSISTENT FROM PREVIOUS FORECAST AND STAY IN THE MVFR CATEGORY. FEEL
CLOUDS WILL LOWER AND INCREASE THROUGH SUNDAY WITH VICINITY
SHOWERS ACROSS THE AREA. WINDS WILL VEER AROUND TO THE EAST-
SOUTHEAST BY THE AFTERNOON.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 330 PM SAT...EXPECT MAINLY VFR CONDITIONS THROUGH THE
EXTENDED...THOUGH SOME SHOWERS/STORMS MAY PRODUCE TEMPO SUB VFR
CONDITIONS ON MONDAY. LIGHT WINDS EACH NIGHT WITH PARTLY CLOUDY
SKIES MAY LEAD TO FOG/BR LATE NIGHT AND EARLY MORNING THROUGH THE
WEEK.

.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 950 PM SATURDAY...FRONTAL BOUNDARY REMAINS STALLED OVER THE
CENTRAL WATERS WITH NE WINDS AT OREGON INLET...BUT MOSTLY S/SW
WINDS SOUTH OF THERE. SEAS ARE GENERALLY 1 TO 3 FEET WITH SOME
LONG PERIOD (10 TO 11 SECOND) SWELLS. THE WEAK FRONT WILL REMAIN
STALLED ALONG THE CENTRAL OUTER BANKS TONIGHT WITH WINDS SPEEDS
REMAINING LIGHT. THE FRONT BECOMES MORE DIFFUSE ON SUNDAY WITH
WINDS E/SE NORTH OF THE BNDRY...AND S/SW TO THE SOUTH. WINDS
SPEEDS WILL REMAIN GENERALLY 10 KT OR LESS EARLY...PICKING UP TO
10-15 KTS IN SOME AREAS DURING THE AFTN.

SEAS WILL AVERAGE 2-3 FT THROUGHOUT BUT WITH INCREASING WAVE
PERIOD FROM DISTANT TROPICAL STORMS OVER THE MID ATLC OCEAN.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 330 PM SAT...A WEAK BOUNDARY WILL REMAIN STALLED NORTH OF
THE WATERS SUN THROUGH TUES...THEN AN AREA OF LOW PRESSURE WILL PASS
NORTH OF THE REGION WED AND THURS WITH GENERALLY UNSETTLE WEATHER
EXPECTED FOR THE COASTAL WATERS. SCATTERED CONVECTION POSSIBLE
THROUGHOUT THE LONG TERM.

BIGGEST CONCERN FOR THE MARINE FORECAST WILL BE INCREASED SWELL
ENERGY ASSOCIATED WITH TROPICAL STORM LESLIE...CURRENTLY LOCATED
ABOUT 500 MILES EAST OF THE LESSER ANTILLES. TS LESLIE IS EXPECTED
TO BECOME A HURRICANE THIS WEEKEND AS FCST BY NHC THEN MOVE SLOWLY
TOWARDS BERMUDA. LESLIE IS ALSO FORECAST TO BECOME QUITE
LARGE...WHICH WILL AID IN PRODUCING LONG PERIOD SWELLS OF 13-15
SECONDS MON NIGHT THROUGH LATE WEEK. SEAS WILL ALSO BUILD TO 4-6
FT BY TUES AFTERNOON AND INC TO AT LEAST 5 TO 7 FEET MID TO LATE
WEEK WHICH WILL LIKELY PRODUCE DANGEROUS SURF CONDITIONS WITH
BREAKING WAVES AS LARGE AS 6-9 FEET. HIGH THREAT OF RIP CURRENTS
WILL LIKELY GO INTO EFFECT EARLY THIS WEEK AND PERSIST THROUGH
LATE WEEK. BOTH LOCAL SWAN AND WAVEWATCH III STRUGGLED WITH
WAVES/SWELL MON THROUGH LATE WEEK SO GRIDS WERE EDITED TO BETTER
REFLECT WNA SPECTRAL FORECAST DATA.

.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.

SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...BTC/TL
AVIATION...CTC/TL/LEP
MARINE...CTC/BTC/TL

AREA FORECAST DISCUSSION

NWS RALEIGH NC

144 AM EDT FRI AUG 31 2012

.SYNOPSIS...
AN UPPER LEVEL RIDGE WILL STRENGTHEN OVER THE AREA THROUGH
SATURDAY... RESULTING IN ABOVE NORMAL TEMPERATURES. THE REMNANTS OF
TROPICAL CYCLONE ISAAC WILL APPROACH THE AREA FROM THE WEST EARLY
NEXT WEEK.

.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 1010 PM THURSDAY...

TONIGHT: SURFACE HIGH OFF THE NC COAST WILL YIELD A MOIST SSW RETURN
FLOW OVER CENTRAL NC OVERNIGHT. SKIES HAVE CLEARED ACROSS MOST OF NC
AS OF 02Z. LATEST RUC ANALYSIS SHOWS SURFACE RH OF 95 TO 100 PERCENT
BETWEEN 06 AND 12Z AND SURFACE DEWPOINT DEPRESSIONS OF ONE OR LESS
ACROSS MUCH OF THE AREA BY 09Z...INCREASING SIGNIFICANTLY AFTER 12Z.
THE RUC FORECASTED SURFACE WINDS ARE AROUND 5 KTS AS A SURFACE
TROUGH MOVES ACROSS NORTHERN VA...INCREASING THE PRESSURE GRADIENT
ACROSS THE NORTH EARLY FRIDAY MORNING. IT IS LIKELY THAT FOG WILL
DEVELOP ACROSS MUCH OF THE AREA BETWEEN 09Z AND 12Z...HOWEVER THERE
IS STILL A BIT OF UNCERTAINTY...PARTICULARLY ACROSS THE NORTH WHERE
THE WINDS MAY BE STRONG ENOUGH TO INHIBIT FOG DEVELOPING. HAVE KEPT
AREAS OF FOG IN FOR THE PRE-DAWN HOURS GIVEN THE PERSISTENCE FROM
THURSDAY MORNING...AND THE CLEAR SKIES...LIGHT WINDS AND ABUNDANT
LOW LEVEL MOISTURE. THESE CONDITIONS SHOULD ALSO RESULT IN GOOD
RADIATIONAL COOLING...YIELDING OVERNIGHT LOW TEMPS IN THE MID TO
UPPER 60S. -KC

THERE ARE A COUPLE OF POSSIBLE INHIBITING FACTORS FOR THE
DEVELOPMENT OF DENSE FOG...HOWEVER. ONE IS THE TIGHTENING OF THE
SURFACE PRESSURE GRADIENT AND LEE TROUGH DEVELOPMENT ACROSS NORTHERN
NC...WHICH MAY PRODUCE SOME STIRRING OF SOUTHWESTERLY SURFACE WINDS
OVER THE NORTHERN PIEDMONT AND RESULT IN VERY LOW STRATUS LAYER
AND LIGHTER FOG...VERSUS A HIGHER LIKELIHOOD OF CALM AND DENSE
FOG DEVELOPMENT DIRECTLY WITHIN THE RIDGE AXIS ACROSS SOUTHERN NC.
THE OTHER POSSIBLE INHIBITING FACTOR IS THE POTENTIAL FOR A SCT-BKN
STRATOCUMULUS CLOUD FIELD FROM A RIBBON OF H85 MOISTURE TO ADVECT IN
AN ARC CYCLONICALLY FROM WESTERN TO NORTH CENTRAL TO EASTERN
NC...AFFECTING MAINLY LOCALES NEAR THE VA BORDER IN THE RAH CWFA.

FRI-FRI NIGHT: WARMER AND MAINLY DRY. A LOW LEVEL THERMAL RIDGE ON
THE NORTHERN AND NORTHEASTERN PERIPHERY OF THE AFOREMENTIONED MID
LEVEL RIDGE AND CHARACTERIZED BY TEMPERATURES ALREADY IN THE UPPER
90S TO LOWER 100S OVER NE AND IA AT 18Z...WILL ADVECT EASTWARD TO
THE MIDDLE ATLANTIC STATES AND YIELD PROJECTED LOW LEVEL THICKNESSES
NEAR 1430 METERS AT GSO BY 00Z/1ST. SUCH THICKNESSES SHOULD SUPPORT
TEMPERATURES MAINLY IN THE 89 TO 94 DEGREE RANGE UNDER A MOSTLY
SUNNY SKY. CONVECTIVE POTENTIAL WILL REMAIN QUITE LOW...AND HAS BEEN
LEFT OUT OF THE FORECAST GIVEN THE SUBSIDENT AND CAPPING INFLUENCE
OF THE RIDGE ALOFT...DESPITE SHALLOW LOW LEVEL CONVERGENCE AND BL
MOISTURE GRADIENT INVOF THE PIEDMONT SURFACE TROUGH AXIS. CONTINUED
MAINLY CLEAR...BUT MILDER WITH A SOUTHWESTERLY STIRRING WIND AS THE
SURFACE TROUGH FURTHER STRENGTHENS...WITH LOWS WITHIN A COUPLE OF
DEGREES OF 70.

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 235 PM THURSDAY...

FOR SATURDAY/SATURDAY NIGHT: BASED ON THE LATEST MODEL OUTPUT...
THERE IS A RISING RISK FOR LATE AFTERNOON/EVENING STORMS SATURDAY. A
MID LEVEL TROUGH AXIS SWINGING (WITH A SLIGHT POSITIVE TILT) THROUGH
THE NORTHEAST STATES WILL HELP PUSH A BACKDOOR FRONT SOUTHWARD
TOWARD (BUT NOT INTO) NC... WITH LEESIDE TROUGH DEVELOPMENT LIKELY
OVER CENTRAL NC. AS FRIDAY`S MID LEVEL ANTICYCLONE CENTER GETS
SUPPRESSED TO OUR SOUTH... MID LEVEL FLOW WILL STRENGTHEN FROM THE
NORTHWEST. THE RESULTING INCREASE IN DEEP LAYER SHEAR (YET STILL
MODEST AT JUST 15-20 KTS) ACCOMPANIED BY IMPROVING THERMODYNAMICS
(1200-2000 J/KG OF MLCAPE) AND RISING PW TO 1.8-2.0 INCHES WILL
SUPPORT A FEW AFTERNOON SHOWERS AND STORMS... INCLUDING THOSE
EXPECTED TO DEVELOP OVER THE HIGHER TERRAIN AND DROP SOUTHEASTWARD
INTO THE FORECAST AREA LATE IN THE DAY. LOW LEVEL THICKNESSES WILL
BE ABOUT 15-25 METERS ABOVE NORMAL... WHILE 700 MB TEMPS RISE TO
11-12C... COMPARABLE TO UPSTREAM VALUES WHERE SURFACE TEMPS EARLY
THIS AFTERNOON HAD ALREADY EXCEEDED 90. EXPECT HIGHS OF 90-94. WARM
LOWS OF 69-73 WITH MOSTLY CLOUDY SKIES AS CONVECTIVE DEBRIS AND
MID-HIGH CLOUDS STREAMING FROM ISAAC OVERSPREAD THE REGION.

FOR SUNDAY/SUNDAY NIGHT: THIS IS ABOUT THE TIME WE SHOULD BEGIN TO
FEEL THE DIRECT EFFECTS OF THE REMNANTS OF ISAAC. THE CENTER OF THE
REMNANT SURFACE CYCLONE IS EXPECTED TO BE OVER SRN IL SUNDAY
MORNING... DRIFTING INTO INDIANA BEFORE IT BEGINS TO GET ABSORBED
INTO THE SURFACE FRONTAL SYSTEM APPROACHING FROM THE NW. MODELS
SUPPORT HOLDING A WEAK FRONTAL ZONE ORIENTED ROUGHLY FROM KY ACROSS
SW NC AND ALONG THE NC/SC BORDER... AND THIS MAY REMAIN A FOCUS FOR
SCATTERED STORMS DEVELOPING WITH DAYTIME HEATING AND DESTABILIZATION
(MLCAPE OF 1500-2400 J/KG)... AND WITH DEEP LAYER SHEAR INCHING UP A
BIT TO 20-25 KTS. PW VALUES WILL STAY QUITE HIGH... CLOSE TO 2.0
INCHES... SO IT SHOULD NOT TAKE MUCH TO INDUCE CONVECTION. HAVE
BUMPED UP POPS TO A 40-50 PERCENT CHANCE... MAINLY AFTERNOON THROUGH
EVENING. HIGHS 85-89 WITH GENERALLY MOSTLY CLOUDY SKIES. LOWS 68-72
WITH LOWER RAIN CHANCES OVERNIGHT. -GIH

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 115 PM THURSDAY...

FOR MONDAY/MONDAY NIGHT: MODELS AGREE ON ISAAC`S CORRESPONDING MID
LEVEL SHORTWAVE TROUGH SLOWLY PASSING OVER KY/TN AS IT APPROACHES NC
FROM THE WEST... ALTHOUGH MODEL SOLUTIONS VARY WITH RESPECT TO ITS
SPEED AND AMPLITUDE. WITH A STRONG MID LEVEL RIDGE COVERING THE
DESERT SOUTHWEST AND A FAST FLOW OVER THE NORTHERN PORTION OF THE
CONUS... THIS WAVE SHOULD SLOWLY DEAMPLIFY AS POLAR SHORTWAVE ENERGY
DROPS ESE THROUGH ONTARIO... BUT IT SHOULD REMAIN A DISTINCT AND
TRACKABLE WAVE AS IT MOVES INTO THE SRN APPALACHIANS. THE GFS/ECMWF
BOTH DEPICT WEAK NW-SE WARM FRONTOGENESIS OVER THE CAROLINAS AS THE
WAVE APPROACHES... AND BOTH ALSO DEVELOP WIDESPREAD CONVECTION
MONDAY AFTERNOON ACCOMPANYING THE MID LEVEL HEIGHT FALLS WITH
CONFLUENT GULF- AND ATLANTIC-SOURCE SOUTHEAST AND SOUTHERLY LOW
LEVEL FLOW. GIVEN THE IMPROVING DYNAMICS AND INSTABILITY... WILL
HAVE GOOD CHANCES OF SHOWERS AND A FEW STORMS MONDAY AFTERNOON AND
EVENING... DECREASING WITH LOSS OF HEATING OVERNIGHT. THICKNESSES
POINT TO HIGHS IN THE MID 80S. IT`S WORTH NOTING THAT IF THE LOW
LEVEL WARM FRONT SETS UP TO OUR SOUTH WITH NUMEROUS SHOWERS OVER
CENTRAL NC WITHIN THE BIT MORE STABLE AIR... WE COULD SEE COOLER
TEMPS THAN ARE CURRENTLY ANTICIPATED.

FOR TUESDAY THROUGH THURSDAY: A MARKED DIVERGENCE IN MODEL SOLUTIONS
BECOMES PROBLEMATIC FOR OUR DAY-TO-DAY FORECAST STARTING TUESDAY.
ACCORDING TO THE 00Z/06Z GFS... THE WEAKENING MID LEVEL TROUGH IS
EXPECTED TO HAVE SHIFTED SE OF THE CWA BY WEDNESDAY MORNING AS THE
MEAN LONGWAVE TROUGH DIGS FROM JAMES BAY THROUGH THE ERN GREAT LAKES
TO THE MIDATLANTIC COAST... AND AS A SURFACE COLD FRONT PUSHES SE
THROUGH CENTRAL NC. BUT THERE ARE INDICATIONS THAT THE 00Z/06Z GFS
MAY BE TOO AGGRESSIVE WITH ITS NORTHEAST-NOAM HEIGHT FALLS... AS THE
00Z ECMWF FAVORS DIGGING A TROUGH MUCH MORE WESTWARD INTO MT/ID BY
LATE TUESDAY NIGHT. THE ECMWF (WHICH IS THE STRONGEST WITH ISAAC`S
REMNANT MID LEVEL SHORTWAVE TROUGH) ALSO DEVELOPS A CLOSED LOW WELL
OFF THE BAHAMAS ON SUNDAY AND THEN BRINGS THIS LOW WESTWARD AND
NORTHWESTWARD TOWARD THE SOUTHEAST COAST BY LATE TUESDAY. IN TERMS
OF SENSIBLE WEATHER... THIS RESULTS IN STORMY-EARLY-BUT-CLEARING
WEATHER DURING THIS PERIOD ON THE GFS... AND MILD AND QUITE
WET/STORMY (ALMOST TROPICAL-LIKE) ON THE ECMWF. THE ECMWF ENSEMBLE
MEAN PROVIDES A MIDDLE-OF-THE-ROAD SOLUTION... GRADUALLY DEEPENING
THE LONGWAVE TROUGH OVER THE UPPER MIDWEST AND WRN GREAT LAKES... A
LITTLE WEST OF THE 00Z/06Z GFS BUT CLOSER IN LINE WITH THE NEW 12Z
GFS. FAVORING THIS... EXPECT A GOOD CHANCE OF SHOWERS/STORMS THROUGH
TUESDAY... DECREASING WEST BUT REMAINING FAIRLY HIGH IN THE EASTERN
FORECAST AREA ON WEDNESDAY... AND A LOWER CHANCE ON THURSDAY AS THE
SURFACE FRONT SHOULD BE EAST OF THE AREA WITH DRIER AIR FILTERING IN
FROM THE NW. BUT CONFIDENCE IN THE DETAILS HERE IS RATHER LOW... AND
THIS SCENARIO COULD CHANGE IN THE COMING DAYS AS THE FORECAST IS
REFINED. LOW LEVEL THICKNESSES ARE UNLIKELY TO REACH HIGHLY
ANOMALOUS VALUES... AS THEY SHOULD HOLD WITHIN 5-15 METERS ABOVE
NORMAL. EXPECT HIGHS MOSTLY IN THE MID 80S WITH LOWS IN THE MID 60S
TO NEAR 70. -GIH

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 140 AM FRIDAY...

24-HR TAF PERIOD:
A CONTINUED MOIST BOUNDARY LAYER COUPLED WITH LIGHT AND VARIABLE TO
CALM WINDS AND CURRENT CLEAR SKIES WILL LEAD TO ANOTHER MORNING OF
LOW STRATUS AND FOG ACROSS CENTRAL NC. EXPECT THE WORST CONDITIONS
TO BE ACROSS SOUTHERN AND POSSIBLY EASTERN PORTIONS OF THE AREA...
WHERE IFR/LIFR CONDITIONS WILL BE POSSIBLE (KRWI/KFAY). FURTHER
NORTH AND WEST... A DEVELOPING SURFACE TROUGH MAY PREVENT WINDS FROM
GOING CALM. THIS WOULD LOWER THE PROBABILITY OF DENSE FOG... AND
POSSIBLE FAVOR MORE STRATUS (ESPECIALLY AT KGSO/KINT). THUS... WILL
CONTINUE TO GO WITH A COMBINATION OF STRATUS AN FOG AT THESE SITES
(KGSO/KINT/KRDU)... WITH GENERALLY MVFR/IFR CONDITIONS DEVELOPING
THIS MORNING IN THE PRE-DAWN HOURS. EXPECT AND LOW STRATUS AND OR
FOG TO LIFT/DISSIPATE BY 15/16Z AT THE LATEST. VFR CONDITIONS ARE
EXPECTED AFTER THE FOG AND STRATUS LIFT ALONG WITH CONTINUED DRY
WEATHER... AS STRONG HIGH PRESSURE ALOFT BUILDS OVER THE AREA.

LOOKING AHEAD:
VFR CONDITIONS ARE EXPECTED TO RULE THROUGH SAT NIGHT IN ASSOCIATION
WITH THE AFOREMENTIONED UPPER LEVEL RIDGE...THOUGH A SMALL CHANCE
FOR SHOWERS/STORMS CANNOT BE RULED OUT SAT AFTERNOON/EVENING... BEST
CHANCE AT KGSO/KINT. THE NEXT CHANCE FOR ADVERSE AVIATION CONDITIONS
WILL BE LATE SUNDAY INTO MON/TUE AS THE REMNANTS OF TROPICAL CYCLONE
ISAAC PROGRESS EAST TOWARD THE REGION.

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

SYNOPSIS...BSD/JB
NEAR TERM...KC/MWS/SEC
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...BSD/VINCENT

AREA FORECAST DISCUSSION

NWS TULSA OK

621 AM CDT FRI AUG 31 2012

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
FOR THE 12Z TAFS... REMNANTS OF TROPICAL SYSTEM ISAAC WILL
CONTINUE MOVING NORTHWARD THROUGH WESTERN ARKANSAS TODAY. OUR ARKANSAS
TAF SITES WILL LIKELY EXPERIENCE IFR CEILINGS WITH RAINFALL AND
WINDS INTERMITTENTLY THROUGHOUT MUCH OF THE DAY. IT IS UNCERTAIN
HOW FAR WEST THE EFFECTS OD ISAAC WILL BE FELT. OKLAHOMA TAF SITES
MAY EXPERIENCE MVFR CEILINGS ALONG WITH RAIN AND SOME WINDS.

.PREV DISCUSSION... /ISSUED 348 AM CDT FRI AUG 31 2012/

DISCUSSION...
REMAINS OF ISAAC ARE CURRENTLY ALONG THE MONTGOMERY/SCOTT COUNTY LINE
IN SWRN AR...AND HAS SHOWN A NNW MOVEMENT OVER THE PAST SEVERAL
HOURS. THE BULK OF THE RAINFALL HAS REMAINED E AND N OF THE
CIRCULATION CENTER...ALTHOUGH HAVE RECENTLY SEEN A NARROW BAND
FAR NERN OK. 06Z NAM SEEMS TO HAVE A REASONABLE HANDLE ON THE TRACK
OF ISAAC...TAKING IT TO JUST E OF FORT SMITH EARLY THIS
MORNING...THEN EVENTUALLY INTO SWRN MO EARLY THIS AFTERNOON.

PERIODS OF SHOWERS AND ISOLATED THUNDERSTORMS ARE A GIVEN ACROSS NWRN
AR...ALTHOUGH POP FORECAST IS QUITE A BIT TRICKIER FARTHER W INTO
ERN OK. NAM AND HRRR BOTH SUGGEST THAT A FEW BANDS OF HEAVIER
SHOWERS COULD EVENTUALLY WRAP BACK DEEPER INTO NERN OK...AND GIVEN
THE RECENT TRENDS...HAVE OPTED TO MAINTAIN THE HIGH POPS FROM THE
PREVIOUS FORECAST. ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE
POSSIBLE ACROSS NWRN AR...ALTHOUGH RECENT DROUGHT CONDITIONS SHOULD
KEEP THE FLOODING POTENTIAL ON THE LOW END. SEVERE WEATHER THREAT
APPEARS MINIMAL AS WELL...WITH THE BEST CHANCES TODAY JUST E OF OUR
FORECAST AREA.

WIND GUSTS HAVE GENERALLY REMAINED BELOW 30-35 MPH OVERNIGHT. WHILE
AN ISOLATED 40 MPH GUST ISNT OUT OF THE QUESTION THIS MORNING...PLAN
ON DROPPING THE WIND ADVISORY WITH THE 4 AM FORECAST PACKAGE.

CIRCULATION CENTER WILL EVENTUALLY PULL NE OF THE REGION TONIGHT
INTO SATURDAY...WITH POPS GENERALLY TAPERING OFF BY LATE IN THE DAY.
MID-LEVEL RIDGING WILL BUILD BACK ACROSS THE SRN PLAINS THIS WEEKEND
AND INTO EARLY NEXT WEEK. EXPECT AFTERNOON TEMPS TO WARM BACK ABOVE
NORMALS...WITH READINGS PUSHING 100F IN SEVERAL SPOTS SUNDAY AND
MONDAY.

THE UPPER RIDGE FLATTENS A BIT BY MID-TO-LATE WEEK...PUTTING
OUR AREA ALONG THE SRN EDGE OF THE WESTERLIES. WILL KEEP
SHOWER/THUNDERSTORM CHANCES AROUND 20/30 PERCENT FOR NOW...ALTHOUGH
THESE NUMBERS MAY GO UP IF GFS REMAINS CONSISTENT WITH POTENTIAL MCS
SETUP WEDNESDAY NIGHT INTO THURSDAY.

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&

AVIATION...06

AREA FORECAST DISCUSSION

NWS TULSA OK

348 AM CDT FRI AUG 31 2012

.DISCUSSION...
REMAINS OF ISAAC ARE CURRENTLY ALONG THE MONTGOMERY/SCOTT COUNTY LINE
IN SWRN AR...AND HAS SHOWN A NNW MOVEMENT OVER THE PAST SEVERAL
HOURS. THE BULK OF THE RAINFALL HAS REMAINED E AND N OF THE
CIRCULATION CENTER...ALTHOUGH HAVE RECENTLY SEEN A NARROW BAND
FAR NERN OK. 06Z NAM SEEMS TO HAVE A REASONABLE HANDLE ON THE TRACK
OF ISAAC...TAKING IT TO JUST E OF FORT SMITH EARLY THIS
MORNING...THEN EVENTUALLY INTO SWRN MO EARLY THIS AFTERNOON.

WIND GUSTS HAVE GENERALLY REMAINED BELOW 30-35 MPH OVERNIGHT. WHILE
AN ISOLATED 40 MPH GUST ISNT OUT OF THE QUESTION THIS MORNING...PLAN
ON DROPPING THE WIND ADVISORY WITH THE 4 AM FORECAST PACKAGE.

.PRELIMINARY POINT TEMPS/POPS...
TUL 84 73 93 72 / 80 30 20 10
FSM 85 73 94 73 / 90 50 30 10
MLC 90 74 97 73 / 40 20 10 10
BVO 85 70 92 68 / 80 30 20 10
FYV 81 73 90 68 / 100 70 40 20
BYV 80 71 88 69 / 100 70 50 20
MKO 85 71 94 71 / 80 40 20 10
MIO 81 73 89 71 / 90 60 40 20
F10 88 73 95 74 / 40 20 10 10
HHW 93 74 95 74 / 20 20 10 10

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&

SHORT TERM...06
LONG TERM....18

AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

1020 PM EDT SAT SEP 1 2012

.SYNOPSIS...
A WEAKENING COLD FRONT WILL STALL OUT ACROSS THE SOUTHERN TIER
OF THE STATE INTO EARLY NEXT WEEK. THE MOISTURE ASSOCIATED WITH
THE REMNANTS OF HURRICANE ISAAC WILL SLIDE EASTWARD ALONG THIS
FRONTAL BOUNDARY THROUGH THE OHIO VALLEY AND ACROSS PENNSYLVANIA
BY MID WEEK. THE HIGHEST CHANCE OF SHOWERS AND THUNDERSTORMS WILL
BE LATER MONDAY INTO WEDNESDAY.

.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
LATEST RUC AND HRRR RUNS HAVE DONE WELL WITH THE LAST FEW HOURS OF
VERIFIABLE WEATHER. THEREFORE...SE NO REASON TO DEVIATE FROM THEIR
GUIDANCE. THEY BOTH PLAY UP A SIMILAR SITUATION TO THE NAM12 -
GENERATING ONLY SCT SHRA OVER THE WEST-CENTRAL/SOUTHWEST EARLY
TONIGHT...BUT BRING MORE-WIDESPREAD SHOWERS BACK TO THAT AREA
LATE TONIGHT. QPF SHOULD BE GENERALLY LIGHT WITHOUT SUFFICIENT
INSTABILITY TO TAP DEEP MSTR. NEW NAM DOES LEAVE MEAGER 8H
INSTABILITY EVEN INTO THE CENTRAL MTS...SO CANNOT RULE OUT A
SHOWER THERE. BUT LOWER-BASED INSTABILITY SHOULD STAY TO THE S/W
OF KJST. HAVE LEFT OUT MENTIONS OF THUNDER FROM MOST LOCATIONS
THRU THE NIGHT...BUT BRING IT BACK TO THE WX GRIDS AROUND SUNRISE.

.SHORT TERM /7 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
DID ADJUST POPS UP SOME...ESP IN THE SRN TIER. 00Z NAM MAKES
SUNDAY LOOK VERY SIMILAR TO TODAY WITH NIL QPF IN THE HIGHLY-
STABLE AIR OF THE NERN COS...AND VERY HIGH POPS IN THE DEEP PWATS
ACROSS PRETTY MUCH ALL THE SRN TIER. TEMPS MAY BE COOLER THAN FCST
OVER THE SERN HALF OF THE AREA DEPENDING ON HOW MANY BREAKS CAN
DEVELOP IN THE EXPECTED MOSTLY-CLOUDY CONDITIONS. LEFT TEMPS ALONE
FOR THE TIME BEING...AND WAIT FOR NEWEST 00Z MOS GUIDANCE TO
CONTEMPLATE ANY CHANGES.

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
BROAD CONSENSUS AMONG MDL DATA THAT REMNANTS OF ISAAC WILL MERGE
WITH QUASI-STATIONARY FRONT OVER PA LATE MONDAY AND TUESDAY...PRODUCING
A WIDESPREAD MODERATE TO LOCALLY HVY RAINFALL. HAVE INCREASED POPS
TO ARND 70 PCT MON NIGHT AND TUESDAY...WHEN GEFS 8H MFLUX VALUES
SURGE TO NR +2SD WITH PASSAGE OF ISAAC REMNANTS. CURRENT GEFS MEAN
48HR RAINFALL ENDING TUE NIGHT RANGES FROM BTWN 1 TO 1.5 INCHES
ACROSS CENTRAL PA. HOWEVER...INDIVIDUAL ENS MEMBERS AND OPER MDL
RUNS SUGGEST LOCALIZED AMTS BTWN 2-3 INCHES POSSIBLE. USED MOS
GUIDANCE TO NARROW DOWN THE TIMING FOR HIGH QPF. A QUICK LOOK AT
FLASH FLOOD GUIDANCE SHOWS MOST OF CENTRAL PA CAN HANDLE UP TO 4
INCHES OF RAIN WITHIN A 6HR PERIOD BEFORE ANY SIG FLOODING.

AS THE REMNANTS OF ISSAC ARE ABSORBED IN THE UPPER TROUGH...THERE
REMAINS HIGHER PWATS AND BL MOISTURE THROUGH WEDNESDAY INTO
THURSDAY. PA WILL REMAIN IN A WARM...UNSTABLE REGIME ON THE EAST
SIDE OF DIGGING TROUGH OVR THE GRT LKS. GIVEN THE AMPLE MOISTURE
AND THE INSTABILITY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS REMAIN
POSSIBLE THROUGH THIS PERIOD. THIS IS ESPECIALLY TRUE ON THURSDAY
AS MED RANGE GUIDANCE CURRENTLY BRINGS A WEAK COLD FRONT THRU
THURSDAY. THE RETURN OF PARTIAL SUNSHINE SHOULD ALLOW DAYTIME
TEMPS TO GET BACK INTO THE 80S WED BASED ON GEFS MEAN 8H TEMPS NR
16C.

ZONAL FLOW WILL RETURN ALONG WITH THE ADVECTION OF DRIER
AIR...LATE THURSDAY INTO FRIDAY. A FAIR AMT OF AGREEMENT THAT HIGH
PRES ALONG WITH DRIER/COOLER AIR WILL BE ARRIVING LATE WEEK AND
THROUGH THE WEEKEND. THE MODELS DO DISAGREE ON THE TIMING OF THE NEXT
SYSTEM...WHICH COULD BE DUE LATE NEXT WEEKEND TO EARLY NEXT WEEK.

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
SCT SHRA/TSRA KJST AND KAOO SOUTHWARD. OTHERWISE...MAINLY HI
CLDS ACROSS THE AREA...BEFORE SOME FOG AND HZ LATER TONIGHT. WINDS
WILL BE ON THE LIGHT SIDE.

SUNDAY WILL BE SIMILAR TO TODAY...WITH CHC AFTERNOON/EVENING SHRA
AND TSRA CONFINED TO THE SOUTHERN TERMINALS. GFS HAS HIGHEST QPF
SW AND SE OF CENTRAL PA ON SUNDAY... THUS THINK MUCH OF THE DAY
WILL BE DRY AND VFR CONDITIONS... AFTER THE FOG AND HZ BURNS OFF
BY MID TO LATE MORNING.

HIGHER CHC OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO
WED...WITH LOWER CIGS ETC...AS THE REMAINS OF ISAAC TRACK
EASTWARD ALONG THE STALLED FRONTAL BOUNDARY NEAR SOUTHERN PA.

OUTLOOK...
MON...SCT SHOWERS AND ISOLATED AFT TSRA. PERIODS OF LOW CIGS
POSSIBLE...MAINLY LATE.
TUE...SHOWERS LIKELY WITH SCT TSTMS. PERIODS OF LOW CIGS POSS.
WED...SCT SHOWERS AND ISOLATED AFT TSRA. PERIODS OF LOW CIGS POSS.
THU...IMPROVING CONDITIONS...AS WINDS SHIFT TO THE NW.

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

$$
SYNOPSIS...DANGELO/MARTIN
NEAR TERM...DANGELO
SHORT TERM...DANGELO/MARTIN
LONG TERM...FITZGERALD/CERU
AVIATION...DEVOIR/MARTIN

AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

822 PM EDT SAT SEP 1 2012

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SHOWERS AND STORMS CONTINUE ACROSS THE SRN MTS AND INTO THE GREAT
VALLEY AND JUST FAR ENOUGH INTO THE SUSQ VALLEY TO CAUSE PROBLEMS.
WHILE HEAVY RAIN IS THE MODE OF THESE STORMS...AND SOME HAVE BEEN
TRAINING...THERE HAVE BEEN SPORADIC LIMB/TREE DAMAGE AND MULTIPLE
PEA-SIZED HAIL REPORTS ASSOCIATED WITH ONE STORM WHICH PASSED
THROUGH SRN ADAMS CO EARLIER THIS EVENING. THE HEAVIEST OF THE
RAIN HAS NOT BEEN ENOUGH TO CAUSE FLOODING WITH FFG/S 2-3 INCHES
IN ONE HOUR. THE PWATS ARE NOT QUITE HIGH ENOUGH FOR THESE VALUES
TO BE SUSTAINED FOR MORE THAN A FEW MINUTES AT ANY SPOT SINCE THE
CELLS ARE MOVING STEADILY SOUTHEASTWARD.

A VERY HUMID AIR MASS IS IN PLACE JUST TO THE SOUTHWEST OF THE
REGION AND THIS MOISTURE IS FEEDING THE THUNDERSTORMS. MULTIPLE
BOUNDARIES AND THE LARGER-SCALE AIR MASS DIFFERENCE WILL KEEP
AREAS/LINES OF FOCUS AVAILABLE ALL NIGHT. BUT BASED ON LATEST RUC
AND HRRR RUNS AND LOSS OF SOLAR HEATING...EXPECT SOME IF NOT MOST
OF THE STORMS/SHOWERS TO DWINDLE EARLY TONIGHT...ESP THE STUFF
OVER THE SC MTS. BUT THE SHOWERS OVER THE LAURELS WILL MOST LIKELY
RETURN EVEN IF THEY DO DIMINISH EARLY TONIGHT. POPS WILL BE
ADJUSTED ACCORDINGLY FOR TIMING.

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
FOR SUNDAY...DID ADJUST POPS SOME. ALSO BROUGHT TEMPS UP
SOME...GIVEN TYPE OF AIR MASS WE HAVE IN PLACE. GFS HINTS THAT
LOWEST QPF WILL BE ACROSS CENTRAL AND NORTHERN PA...WITH HIGHER
QPF AND POPS ON ORDER ACROSS THE SW AND SE...DID NOT WANT TO GO
TOO HIGH WITH POPS...GIVEN THE SPOTTY COVERAGE THAT IS POSSIBLE.
HOWEVER...IF RADAR OVER OHIO THIS EVENING IS ANY INDICATION OF
WHAT KIND OF SET-UP WE HAVE IN STORE SUNDAY...THEN HIGHER POPS MAY
BE ON ORDER.

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
SCT SHRA/TSRA KJST AND KAOO SOUTHWARD. OTHERWISE...MAINLY HI
CLDS ACROSS THE AREA...BEFORE SOME FOG AND HZ LATER TONIGHT. WINDS
WILL BE ON THE LIGHT SIDE.

HIGHER CHC OF SHOWERS AND THUNDERSTORMS LATE MONDAY INTO
WED...WITH LOWER CIGS ETC...AS THE REMAINS OF ISAAC TRACK
EASTWARD ALONG THE STALLED FRONTAL BOUNDARY NEAR SOUTHERN PA.

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

$$
SYNOPSIS...MARTIN
NEAR TERM...DANGELO
SHORT TERM...DANGELO/MARTIN
LONG TERM...FITZGERALD/CERU
AVIATION...DEVOIR/MARTIN

AREA FORECAST DISCUSSION...UPDATED

NWS ABERDEEN SD

1223 AM CDT FRI AUG 31 2012

.UPDATE...
THE AVIATION DISCUSSION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.

00Z 300/500MB ANALYSIS INDICATED A LARGE UPPER RIDGE OVER THE
CENTRAL CONUS WITH A TROUGH OF LOW PRESSURE OVER THE PAC NW. THE
REMNANTS OF ISAAC WERE LIFTING NEWD THRU THE LOWER/MID MISSISSIPPI
VALLEY. AT THE SFC...HIGH PRESSURE CENTERED OVER ND IS EXPECTED
TO BUILD S/SEWD OVERNIGHT. SFC DEWPOINTS THIS EVENING ARE RANGING
FROM THE LOWER 50S OVER NERN SD...DOWN TO THE MIDDLE 30S OVER
CENTRAL AND WRN SD.

TEMPERATURES EARLY THIS EVENING ARE DROPPING OFF PRETTY QUICKLY
DUE TO THE DRY AIRMASS...AND MOSTLY CLEAR SKIES. HOWEVER...LATEST
IR SATELLITE IMAGERY INDICATES A FAIRLY WIDESPREAD AREA OF MID
LEVEL CLOUDINESS ADVECTING INTO THE AREA FROM THE SW IN THE RIGHT
ENTRANCE REGION OF THE UPPER JET. IN FACT KVTN ACTUALLY REPORTED
LIGHT RAIN/SPRINKLES...WHICH IS PRETTY AMAZING CONSIDERING THE
VERY DRY AMS EVIDENT IN THE KLBF 00Z RAOB. ALSO INTERESTING TO
NOTE THAT THE 22Z HRRR INDICATES A FEW SPRINKLES MOVING INTO THE FAR
SW LATER TONIGHT. WILL LEAVE FORECAST DRY FOR NOW DUE TO VERY DRY
AIR AT LOW LEVELS...BUT A FEW SPRINKLES/LIGHT SHOWERS ARE
POSSIBLE. TOUGH CALL ON HOW LOW TO GO WITH LOW TEMPERATURES AS
WELL. DECIDED TO DROP LOW TEMPERATURES A FEW DEGREES IN THE
EAST...BEFORE THICKER CLOUD COVER MOVES IN AFTER 06Z. UPDATES
OUT...

&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT

SPRINKLES AND DRY LIGHTNING CONTINUE FROM WEST CENTRAL MN
SOUTHWEST INTO SOUTH CENTRAL SD THIS AFTERNOON BEHIND A TRAILING
COLD FRONT. THIS ACTIVITY IS EXPECTED TO EXIT THE REGION OVER THE
NEXT 2 TO 3 HRS. HIGH PRESSURE WILL BUILD IN OVERNIGHT BRINGING
DRY CONDITIONS AND ABOVE AVERAGE TEMPERATURES THROUGH SATURDAY.

A LLJ WILL DEVELOP OVER THE WESTERN CWA EARLY ON SATURDAY MORNING.
DECIDED NOT TO MENTION POSSIBILITY OF PRECIP AT THIS POINT BECAUSE
LOWER LEVELS WILL BE VERY DRY...AND BEST FORCING WILL BE IN ND.
WINDS WILL INCREASE AHEAD OF THE LEE SIDE TROF FRIDAY AND
SATURDAY. MAY NEED TO ISSUE FIRE WEATHER HEADLINES...ESPECIALLY ON
SATURDAY.

AS THE COLD FRONT MOVES OFF THE ROCKIES SAT EVENING...MODELS ARE
BEGINNING TO DIVERGE FROM PREVIOUS SOLUTIONS. CURRENT RUNS TRACK
THE BULK OF PRECIP OVER ND NOW ON SAT NIGHT. LEFT SOME ISOLATED
POPS ACROSS WESTERN CORSON COUNTY SAT NIGHT BUT MAY NEED TO REMOVE
THESE AS WELL IF MODELS CONTINUE THIS TREND.

HIGHS WILL CLIMB BACK INTO THE 90S OVER THE WEEKEND...ABOUT 10
DEGREES ABOVE AVERAGE IN MOST LOCATIONS.

.LONG TERM...SUNDAY THROUGH THURSDAY

SUNDAY INTO SUNDAY EVENING MODELS ARE CONSISTENT IN SHOWING A WEAK
SFC TROUGH PASSING THROUGH THE AREA...ALTHOUGH MOISTURE AVAILABLE
FOR THIS FEATURE IS RATHER LIMITED. WILL CONTINUE WITH LOW POPS
FOR THE EASTERN CWA SUNDAY INTO SUNDAY NIGHT. BY THE MIDDLE OF THE
WEEK A MORE SIGNIFICANT SHORTWAVE MOVES ACROSS THE AREA AND THE
INHERITED GUIDANCE POPS LOOKED OK FOR THIS POTENTIAL EVENT FOR THE
TIME BEING. THERE ARE STILL TIMING AND PLACEMENT ISSUES WITH THE
MIDDLE OF THE WEEK SYSTEM SO DID NOT STRAY TOO FAR FROM GUIDANCE
AT THIS POINT. TEMPS LOOK TO STAY RATHER WARM THROUGH THE PERIOD
WITH A SLIGHT COOL DOWN TOWARDS THE END OF NEXT WEEK PERHAPS.

.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS. SATELLITE IMAGERY
INDICATING INCREASING MID-LEVEL CLOUDS FROM THE SOUTHWEST...AND
THIS BROKEN DECK OF CLOUDINESS IS EXPECTED TO PERSIST THROUGH MUCH
OF FRIDAY. A FEW SPRINKLES ARE POSSIBLE OVERNIGHT BUT IMPACTS WILL BE
MINIMAL. LIGHT NORTHEAST WINDS OVERNIGHT WILL BECOME E/SELY ON
FRIDAY AS HIGH PRESSURE SLIDES EAST OF THE AREA. A TIGHTER SFC
GRADIENT WILL RESULT IN BREEZY CONDITIONS AFTER 17Z AT
KPIR/KMBG...WITH A FEW GUSTS AROUND 25 KTS.

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.

$$
UPDATE...FOWLE
SHORT TERM...WISE
LONG TERM...TMT
AVIATION...TDK

WEATHER.GOV/ABERDEEN

AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

923 PM CDT SAT SEP 1 2012

.UPDATE...

DRY AIR FROM THE NORTHEAST HAS ERODED THE PRECIPITATION ACROSS FAR
SOUTHEAST WISCONSIN AND SOUTHERN LAKE MICHIGAN. THE LATEST NAM AND
THE HRRR KEEP US DRY THROUGH THE NIGHT...WITH SOME LIGHT PRECIPITATION
SUNDAY MORNING BEFORE NOON.. WILL TRIM BACK THE CHANCES OF RAIN
TONIGHT A LITTLE WITH ONLY THE FAR SOUTHEAST TIP IN A SLIGHT
CHANCE OF SHOWERS.

.AVIATION/06Z TAFS/...

MAINLY VFR CONDITIONS EXPECTED. DRY AIR FROM THE NORTHEAST HAS
ERODED THE PRECIPITATION ACROSS FAR SOUTHEAST WISCONSIN AND
SOUTHERN LAKE MICHIGAN. THE LATEST NAM AND THE HRRR KEEP US DRY
THROUGH THE NIGHT.

STILL SOME POTENTIAL FOR MVFR CIGS IN THE FAR SOUTH...BUT DRYING
TREND MAY KEEP THINGS VFR.

LOW WILL TRACK ACROSS SOUTHERN ILLINOIS TONIGHT THEN REACH
FAR SOUTHERN INDIANA SUNDAY EVENING.

.PREV DISCUSSION... /ISSUED 302 PM CDT SAT SEP 1 2012/

TONIGHT - CONFIDENCE...MEDIUM
FAR SOUTHERN AREAS STILL VULNERABLE TO NORTHERN PERIPHERY OF ISAAC.
CONVECTION HAS DEVELOPED NORTH OF THE MAIN RAIN SHIELD IN BETTER
FRONTOGENETICAL FORCING ZONE AND HAS TRENDED NW A BIT TOWARDS SRN
TIER OF COUNTIES. 12Z 850 ANALYSIS SHOWED 3C DEW POINT AT GRB WITH
STEADY NE WIND WITH 16C DEW POINT IN CENTRAL IL WITH A SOUTH WIND AT
30 KNOTS. SO FAIR AMOUNT OF LOWER LEVEL CONVERGENCE WITH LIMITED
ELEVATED INSTABILITY. WILL KEEP HIGHEST POPS IN THE SOUTHERN
COUNTIES THROUGH 00Z. AXIS OF MAIN RAIN AREA FURTHER SOUTH OF THE
CONVECTIVE BAND IS BREAKING UP WITH A SUBTLE SHIFT TO THE NORTH.
UPPER LOW IN CENTRAL MO WILL BE TRACKING DUE EAST WITH LOW LEVEL
EASTERLY FLOW MAINTAINING A PRETTY DECENT DRY FEED. LOW LEVEL RH
PROGS DO SHOW A BUMP NORTH IN THE BETTER 925-850 RH AS THE NIGHT
WEARS ON. CLOUDS AND EAST WINDS WILL LIKELY KEEP TEMPS FROM FALLING
AS MUCH AS IN THE NORTHERN CWA WHERE MORE IN THE WAY OF SCT THIN
CIRRUS EXPECTED.

SUNDAY - CONFIDENCE...MEDIUM
UPPER LOW TRACKS FROM SRN IL TOWARDS KENTUCKY WITH 500 MILLIBAR
RIDGE AXIS TAKING HOLD DURING THE AFTERNOON. APPEARS BEST CHANCE OF
ANY SHRA WILL BE IN THE MORNING AND AGAIN IN THE FAR SOUTH BEFORE
INFLUENCE OF CIRCULATION SHIFTS AWAY. LOW LEVEL RH PROGS SUGGEST
IMPROVEMENT IN THE AFTERNOON AS 90 PCT PLUS LOWERS.

SUNDAY NIGHT...FORECAST CONFIDENCE IS HIGH.

A NARROW HIGH PRESSURE RIDGE SETTLES OVER THE AREA...EXTENDING
ACROSS THE GREAT LAKES FROM ITS PARENT HIGH OVER NEW ENGLAND. THE
LOW PRESSURE SYSTEM THAT WAS ISAAC HAS WEAKENED AND MOVED TO THE
OHIO VALLEY. SO QUIET THIS PERIOD.

MONDAY AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM.

NOW THAT THE UPPER LOW ASSOCIATED WITH ISAAC HAS OPENED UP AND
PUSHED INTO THE SOUTHEAST U.S...THE MID LEVEL FLOW OVER THE UPPER
MIDWEST BECOMES FAST AND ZONAL. QUEUE THE SHORT WAVE TRAIN. THE
FIRST OF THESE PUSHES IN TO OUR NORTH WITH AN ATTENDANT WEAK...AND
WEAKENING...COLD FRONT. THIS COULD SET OFF SOME SHOWERS AND STORMS
IN THE WEST MONDAY AFTERNOON. THE DAY 3 SPC OUTLOOK HAS THE SLIGHT
RISK PUSHING INTO MUCH OF OUR NORTHERN TIER ON MONDAY. THIS LOOKS
TOO AGGRESSIVE GIVEN THE TIMING...THE AVAILABLE FORCING AND MASS
FIELDS. I SUSPECT AN ADJUSTMENT FARTHER NORTH AND WEST IS LIKELY
WHEN IT BECOMES THE DAY 2 OUTLOOK...OR DROPPED ENTIRELY.

ANOTHER SHORT WAVE WITH BETTER DEFINITION AND A SHARPER TROF ARRIVES
LATE MONDAY NIGHT AND TUESDAY. THIS SHOULD BRING A HIGHER CHANCE OF
SHOWERS AND STORMS. SOUNDINGS SHOW PLENTY OF AVAILABLE CAPE WITH
THE MID LEVELS COOLING AND SURFACE TEMPS STILL HITTING THE MID
80S.

WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH.

ALL THE MODELS AGREE ON A MUCH STRONGER SHORT WAVE DIGGING INTO
THE GREAT LAKES ON WEDNESDAY. SHOWERS AND STORMS LIKELY MOST
PLACES. CAPE VALUES SHOULD CLOSE IN ON THE 1500-2000J/KG RANGE.
TIMING IS GOOD WITH A STRONG COLD FRONT PUSHING IN DURING THE LATE
AFTERNOON. DEEP LAYER SHEAR ON THE ORDER OF 30 TO 40KTS.

THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS LOW TO MEDIUM.

THINGS QUIET DOWN...BUT THE UPPER FLOW REMAINS ZONAL AND FAST WITH
HEIGHTS GRADUALLY FALLING AS A LARGE SCALE...EAST-WEST TROF
SLOWLY DROPS OUT OF SOUTHERN CANADA...ROTATING AROUND A HUGE UPPER
LOW OVER HUDSON BAY CANADA. WE/LL BE SUSCEPTIBLE TO MORE WEAK SHORT
WAVE ENERGY PRODUCING A CHANCE FOR SHOWERS FROM TIME TO TIME. BUT
NAILING THAT DOWN THIS FAR OUT IS NEAR IMPOSSIBLE.

AVIATION/00Z TAFS/...DECENT CIRCULATION IN CENTRAL MO PER WATER
VAPOR IMAGERY. 1008MB SURFACE LOW. MID/HIGH CLOUDS WRAPPING INTO SRN
WI ON NORTHERN PERIPHERY OF THIS CIRCULATION. LOW LEVEL EASTERLY
FLOW HELPING TO KEEP LOWER LAYERS DRY FOR NOW. LOW LEVEL RH
PROGS/BUFKIT/MOS ALL SUGGEST POTENTIAL FOR MVFR CONDITIONS SPREADING
NORTH LATER TONIGHT INTO SUNDAY MORNING. WILL MAINTAIN TREND OF
PRIOR TAFS IN LEANING IN THIS DIRECTION. SURFACE UPPER LOW WILL
SLOWLY SHIFT TO SRN IL VICINITY BY MIDDAY SUNDAY. LOW LEVEL EASTERLY
PERSISTS.

MARINE...WILL RETAIN SMALL CRAFT FOR THE SOUTHERN TIER AS WINDS
REMAIN GUSTY WITH THE TIGHTER PRESSURE GRADIENT ASSOCIATED WITH
REMNANTS OF HURRICANE ISAAC. DECENT FETCH WILL ALLOW FOR HIGHER WAVE
HEIGHTS. CORRESPONDING THREAT FOR RIP CURRENTS.

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM CDT SUNDAY FOR LMZ646.

UPDATE...HENTZ
TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR
SUNDAY NIGHT THROUGH SATURDAY...DAVIS

AREA FORECAST DISCUSSION

NWS DENVER CO

310 AM MDT SUN SEP 2 2012

.SHORT TERM...THE UPPER LEVEL RIDGE WILL WEAKEN TODAY WITH
INCREASING SWLY FLOW ALOFT. WATOR VAPOR IMAGERY SHOWS A DISTURBANCE
OVER NWRN CO WHICH WAS TRIGGERING A FEW SHOWERS IN THE NRN MTNS
EARLY THIS MORNING. MEANWHILE A WK FNT WAS MOVING ACROSS NERN CO
THIS MORNING AND WILL BRING SLIGHTLY COOLER TEMPS WITH READINGS ON
AVERAGE 5 DEGREES COOLER THAN SAT OVER THE PLAINS. FOR THIS AFTN
SOUNDINGS HAVE BETTER INSTABILITY ACROSS NERN CO THAN THE LAST FEW
DAYS SO THERE SHOULD BE AT LEAST A SLIGHTLY BETTER CHC FOR TSTMS
ACROSS THE PLAINS INTO THE EVENING HOURS. IN THE MTNS WILL KEEP SCT
TSTMS IN THE FCST FOR THIS AFTN WITH WDLY SCT ACTIVITY OVER THE
HIGHER VALLEYS.

.LONG TERM...A FLAT UPPER RIDGE WILL REMAIN SOUTH OF COLORADO MONDAY
THROUGH TUESDAY NIGHT. THE FLOW ALOFT WILL BE WEST-SOUTHWESTERLY ON
MONDAY...THEN ZONAL MONDAY NIGHT THROUGH TUESDAY NIGHT. THE
SYNOPTIC SCALE ENERGY REMAINS BENIGN THROUGH THE PERIODS. THE LOW
LEVEL PRESSURE GRADIENT IS WEAK THROUGH TUESDAY EVENING SO NORMAL
DIURNAL WIND PATTERNS WILL DOMINATE. A WEAK COLD FRONT AND UPSLOPE
IS PROGGED TO MOVE INTO THE PLAINS LATE TUESDAY NIGHT OR EARLY
WEDNESDAY. FOR MOISTURE...THERE IS SOME IN THE MID AND UPPER LEVELS
MONDAY AND MONDAY EVENING. TUESDAY AND TUESDAY NIGHT LOOK PRETTY
DRY. THE BOUNDARY LAYER DEW POINTS ARE PROGGED IN THE 30 TO MID 40S
F RANGE FOR ALL AREAS BY LATE DAY MONDAY. THEY ARE A BIT LOWER FOR
LATE DAY TUESDAY. PRECIPITABLE WATER VALUES ARE PROGGED IN THE 0.60
TO 0.90 INCH RANGE LATE DAY MONDAY...THEN IN THE 0.55 TO 0.70 INCH
RANGE LATE DAY TUESDAY. THERE IS A TAD OF CAPE OVER THE CWA LATE
DAY MONDAY...THEN ANOTHER SMALL AMOUNT IS PROGGED OVER THE
SOUTHERN CWA LATE DAY TUESDAY. THE QPF FIELDS SHOW A TAD OF
MEASURABLE RAINFALL OVER THE CWA LATE MONDAY...AND A BIT LESS LATE
DAY TUESDAY. THERE IS NOT MUCH A MID LEVEL CAP IN PLACE ON THE
LAPSE RATE FIELDS FOR LATE DAY MONDAY. THERE IS A BIT OF ONE
PROGGED FOR LATE DAY TUESDAY. FOR POPS WILL GO WITH 10-20%S BOTH
LATE DAY MONDAY AND LATE DAY TUESDAY. FOR TEMPERATURES...MONDAY`S
HIGHS ARE 0-1 C COOLER THAN TODAY`S. TUESDAY`S ARE 0-1 C WARMER
THAN MONDAY`S. FOR THE LATER DAYS...WEDNESDAY THROUGH
SATURDAY...THE UPPER RIDGE STAYS SOUTH OF COLORADO WITH ZONAL FLOW
ALOFT THROUGH THURSDAY. MODELS STILL HAVE AN UPPER TROUGH TO PUSH
ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY. THE FLOW IS MORE
NORTHWESTERLY FRIDAY AND SATURDAY. MOISTURE IS POOR ALL FOUR DAYS
FOR ALL THE CWA. A WEAK COLD FRONT IS EXPECTED EARLY ON
WEDNESDAY...THEN A SLIGHTLY STRONGER ONE COMES IN LATE THURSDAY
NIGHT/FRIDAY MORNING.

AVIATION...A WK FNT HAS ALREADY MOVED ACROSS THE AREA AS WINDS HAVE
BEEN LIGHT NNE EARLY THIS MORNING. LATEST RAP AND HRRR SHOW WINDS
BECOMING MORE SELY BY MID MORNING AND KEEP THEM THAT WAY THRU MUCH
OF THE AFTN. INSTABILITY WILL BE BETTER THIS AFTN SO COULD SEE A
TSTM AFFECT THE AIRPORT MAINLY AFTER 21Z. FOR NOW WILL JUST MENTION
VCTS IN THE TAF. FOR THIS EVENING TSTM THREAT SHOULD END BY 01Z OR
SO WITH BEST CHC TO THE N AND E OF THE AIRPORT. WINDS SHOULD BECOME
MORE SSW THIS EVENING.

HYDROLOGY...THERE WILL BE A SLIGHT BETTER CHC OF THUNDERSTORMS THIS
AFTERNOON WITH RAINFALL AMOUNTS AROUND A QUARTER INCH POSSIBLE. AN
ISOLATED STRONGER STORM COULD PRODUCE UP TO ONE HALF INCH IN LESS
THAN 30 MINUTES. THE FLOW ALOFT IS STRONGER TOAY SO STORMS WILL
BE MOVING FAIRLY QUICKLY.

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

SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK

AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

310 AM EDT SUN SEP 2 2012

.SYNOPSIS...
07Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AREA OF UPPER LEVEL
RIDGING REMAINS IN CONTROL FROM THE SOUTHERN PLAINS EASTWARD ALONG
THE NORTHERN GULF COAST TO THE FL PENINSULA. THE EASTERN PORTION OF
THIS RIDGE (INCLUDING OUR REGION) IS WEAKENING WITH TIME AS A STRONG
SHORTWAVE APPROACHES THE SOUTHEAST CONUS FROM THE TN VALLEY...AND A
CUT-OFF LOW RETROGRADES WESTWARD TOWARD THE EASTERN FLORIDA
PENINSULA. 02/00Z KTBW SOUNDING PROFILE SHOWS THAT THE COLUMN DID
DRY OUT SOMEWHAT DURING THE DAY ON SATURDAY...ESPECIALLY ABOVE
500MB...HOWEVER THE LACK OF CONVECTIVE COVERAGE ON SATURDAY WAS
LIKELY MORE TIED TO OUR WARM/CAPPED MID-LEVEL THERMODYNAMIC PROFILE
ASSOCIATED WITH THE UPPER RIDGE. TEMPS AROUND 500MB RANGED FROM -2
TO -5C WHICH ARE FAIRLY WARM...AND WHEN COMBINED WITH THE DRY AIR
ADVECTION WAS ENOUGH TO SUPPRESS CONVECTION.

00Z NWP GUIDANCE SUITE SHOWS THAT THE DEEPEST LAYER DRY AIR WAS "ON
OUR DOORSTEP" AT 00Z AND WAS LIKELY NOT COMPLETELY SAMPLED BY THE
RAOB. WOULD EXPECT TO SEE OUR PW VALUES COME DOWN FURTHER WITH THE
12Z SOUNDING AS THE DEEP LAYER DRY AIR SHOULD BE FIRMLY IN PLACE.

AT THE SURFACE...SUBTROPICAL RIDGE AXIS IS ALIGNED OVER THE NORTHERN
FL PENINSULA AND INTO THE NE GULF OF MEXICO. DEWPOINTS ARE LOW
FOR EARLY SEPTEMBER WITH READINGS THIS PAST EVENING IN THE UPPER 60S
TO LOWER 70S. HAVE SEEN MOST OF THE UPPER 60S REBOUND A FEW
DEGREES...BUT STILL A RATHER COMFORTABLE MORNING COMPARED TO THE
PAST COUPLE MONTHS.

.SHORT TERM (TODAY THROUGH TUESDAY)...
TODAY/TONIGHT...ANOTHER DAY WITH WELL BELOW NORMAL RAIN CHANCES
ACROSS MUCH OF THE FORECAST AREA. SOUTH-NORTH CROSS-SECTIONS THROUGH
THE DAY SHOW A DEEP LAYER OF VERY DRY AIR (RH < 20%) IN PLACE. THIS
LAYER IS DEEP ENOUGH TO BE QUITE HOSTILE TO CONVECTION AND WOULD
THINK EVEN ISOLATED CELLS ARE UNLIKELY FOR MOST LOCATIONS. LATE IN
THE DAY...SOME MOISTURE ADVECTION BEGINS TO IMPINGE ON THIS DRY
LAYER OVER THE FAR NORTHERN ZONES (LEVY/CITRUS/HERNANDO/SUMTER) IN
ADVANCE OF A SHORTWAVE TROUGH DROPPING INTO AL/GA. COLUMN IS STILL
NOT FAVORABLE FOR DEEP CONVECTION...BUT CAN`T RULE OUT A FEW
ISOLATED STORMS FOR THE NORTHERN NATURE COAST...ESPECIALLY WITH THE
SUBTROPICAL RIDGE AXIS POSITION ALLOWING FOR A WELL-DEFINED
SEA-BREEZE FRONT. LOCAL HI-RES WRFARW SEEMS TO HAVE A GOOD HANDLE ON
THIS SITUATION AND DOES SUPPORT A FEW NON-ROBUST SHOWERS NORTH OF
TAMPA BAY AFTER 20Z. OTHERWISE THE LACK OF CONVECTION WILL AGAIN
ALLOW FOR TEMPERATURES AWAY FROM THE BEACHES TO REACH THE 92-95
RANGE. NOT ANTICIPATING ANY HEAT INDEX PROBLEMS AS THE DRIER AIRMASS
HOLDS THESE VALUES GENERALLY BELOW 100. ANY ISOLATED LAND-BASED
SHOWERS UP NORTH SHOULD DISSIPATE WITH SUNSET ALLOWING FOR A DRY AND
QUIET OVERNIGHT PERIOD. MAY SEE A FEW LATE NIGHT SHOWERS OVER THE
NORTHERN COASTAL WATERS IN CLOSER PROXIMITY TO SOME DEEPER MOISTURE
ONCE THE LAND BREEZE BECOMES ESTABLISHED.

MONDAY...UPPER RIDGE CONTINUES TO WEAKEN AS IT IS SQUEEZED BETWEEN
THE SHORTWAVE OVER AL/GA/FL PANHANDLE AND A CUT-OFF LOW APPROACHING
THE SOUTHEAST FL COAST. GUIDANCE SHOWING THAT WE WILL STILL HAVE A
"TONGUE" OF DRIER AIR ABOVE THE SURFACE EXTENDING ACROSS THE CENTRAL
FORECAST PENINSULA IN BETWEEN THESE 2 FEATURES. HOWEVER THE
EXTENT/DEPTH OF THE DRY AIR IS LESS AND WILL RE-INTRODUCE AT LEAST A
SLIGHT CHANCE 20% POP FOR ALL ZONES. BEST CHANCES FOR THE AFTERNOON
SHOWERS ~30% WILL BE DOWN TOWARD FORT MYERS ASSOCIATED WITH THE
SYNOPTIC SUPPORT/COOLER MID-LEVELS AROUND THE UPPER LOW...AND ALSO
UP TOWARD LEVY COUNTY ASSOCIATED WITH THE PROXIMITY TO THE SE CONUS
SHORTWAVE. GFS/ECMWF BOTH SHOW SOME ENHANCED DEEP LAYER (700-300MB)
QG FORCING OVER SOUTH FLORIDA TO THE WEST OF THE UPPER LOW CENTER
MONDAY AFTERNOON...AND COMBINED WITH THE ENHANCED INSTABILITY...
WOULD NOT BE SURPRISED TO SEE A FEW OF THE STORMS OVER THE SOUTHERN
PENINSULA BECOME STRONG. BEST CHANCE FOR THESE ENHANCED UPDRAFTS
WOULD LIKELY BE EAST OF LEE/CHARLOTTE COUNTIES UNDERNEATH THE
COLDEST MID-LEVELS...BUT WORTH WATCHING.

TUESDAY...UPPER LOW BEGIN TO VERY SLOWLY MIGRATE NORTHWARD UP THE
EAST COAST OF THE PENINSULA. OVERALL THE SYNOPTIC PATTERN WILL NOT
HAVE CHANGED MUCH FROM LATE MONDAY. KEEPING RAIN CHANCES SIMILAR
WITH AN EXPANSION OF THE CHANCE 30-40% POPS NORTHWARD INTO
HARDEE/DESOTO/HIGHLANDS/POLK COUNTIES FOLLOWING THE CORE OF THE
UPPER LOW.

.LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)...
UPPER-LEVEL LOW WILL BE TURNING NORTHWARD AND MOVING BY TO OUR EAST
TUESDAY NIGHT AND WEDNESDAY WHICH WILL KEEP THE DEEPER MOISTURE AND
BEST INSTABILITY TO OUR EAST. THE GFS AND ECMWF DIG AN UPPER-LEVEL
TROUGH OVER THE EASTERN STATES ON THURSDAY AND THURSDAY NIGHT WHICH
IN TURN PUSHES AN EARLY SEASON COLD FRONT INTO THE DEEP SOUTH. THE
ECMWF IS THE STRONGEST AND FARTHEST SOUTH WITH THE FRONT...REACHING
OUR NORTHERN ZONES ON FRIDAY. THE GFS HOLDS THE FRONT NORTH OF THE
REGION BUT DOES DISPLACE THE RIDGE AXIS WELL TO OUR SOUTH RESULTING
IN ENHANCED WESTERLY FLOW BETWEEN THE FRONT AND THE RIDGE. THE
DIFFERENCES BETWEEN THE TWO MODELS REALLY SHOWS UP BY SATURDAY WHEN
THE ECMWF SHOWS LOW PRESSURE OFF THE COAST ALONG 30 DEGREES NORTH
LATITUDE WHILE THE GFS SHOWS MAINLY TROUGHING AND SIGNIFICANTLY
FARTHER NORTH. IT IS LIKELY TOO EARLY IN THE SEASON TO GET THE
FRONTAL BOUNDARY AS FAR SOUTH AS SUGGESTED BY THE ECMWF SO WILL USE
THE GFS AS THE BASIS FOR THE EXTENDED FORECAST.

WILL GENERALLY FOLLOW MEX GUIDANCE SHOWING SCATTERED STORMS EACH
DAY. WE MAY HAVE A DAY OR TWO WHERE LOW-LEVEL CONVERGENCE SETS UP IN
PERSISTENT LINES BRINGING SOME LOCALLY HEAVY RAINFALL TO SOME
LOCATIONS...BUT ITS TOO EARLY TO PINPOINT WHERE THIS WILL OCCUR IF
AT ALL.

.AVIATION...
VFR NEXT 24 HOURS. SOME RISK OF BRIEF MVFR VISIBILITIES NEAR SUNRISE
AT PGD AND RSW. NOT EXPECTING ENOUGH AFTERNOON SHRA COVERAGE TO
INCLUDE IN TAFS AT THIS TIME.

.MARINE...
THE SUBTROPICAL RIDGE AXIS ALIGNED OVER THE NORTHEAST GULF OF MEXICO
TODAY WILL SLOWLY SETTLE SOUTHWARD TOWARD THE SOUTHERN PENINSULA AND
SOUTHEAST GULF BY THE MIDDLE PORTION OF THE WEEK. THE CLOSE
PROXIMITY OF THE RIDGE AXIS THROUGH THE FORECAST PERIOD WILL KEEP
WINDS AND SEAS GENERALLY LIGHT ACROSS THE EASTERN GULF WITH EASTERLY
FLOW TODAY TRENDING MORE SOUTH AND SOUTHWEST THROUGH THE UPCOMING
WEEK.

.FIRE WEATHER...
A DRIER LOW LEVEL AIRMASS IN PLACE WILL ALLOW INLAND RELATIVE
HUMIDITY LEVELS TO DROP INTO THE UPPER 30S TO LOWER 40S FOR A BRIEF
TIME THIS AFTERNOON. LDSI VALUES WILL BE UNDER 75 AND WINDS
GENERALLY LIGHT...SO NOT SIGNIFICANT FIRE WEATHER CONCERNS ARE
ANTICIPATED. A SLOW LOW LEVEL MOISTURE RETURN WILL BEGIN DURING THE
EARLY PORTION OF THE WEEK.

.PRELIMINARY POINT TEMPS/POPS...
TPA 92 75 90 76 / 10 10 20 10
FMY 93 73 90 74 / 10 10 30 10
GIF 93 72 92 72 / 10 10 20 10
SRQ 90 73 89 74 / 10 10 20 10
BKV 92 69 92 69 / 20 10 20 10
SPG 93 78 89 78 / 10 10 20 10

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

SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...JILLSON

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

433 AM EDT SUN SEP 2 2012

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM EDT SUN SEP 2 2012

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG AXIS
CENTERED FM FAR NW ONTARIO SWD THRU THE UPR MS RIVER VALLEY BTWN
TROFFING OVER SW CAN/NRN ROCKIES AND ANOTHER UPR TROF IN QUEBEC. SFC
HI PRES CENTERED JUST E OF LK SUP AND DRY AIRMASS SHOWN ON THE 00Z
GRB ARE BRINGING A TRANQUIL EARLY MRNG TO UPR MI. TO THE S...THE
REMNANTS OF HURRICANE ISAAC/DEEP MSTR ARE IN THE OHIO RIVER VALLEY.
TO THE W...THERE ARE CLUSTERS OF SHRA/TS IN THE NRN PLAINS ALONG A
COLD FNT ASSOCIATED WITH UPR TROF/STRONG SHRTWV OVER ALBERTA THAT IS
DRIFTING SLOWLY ENEWD. COVERAGE OF SHRA IN THE NRN PLAINS IS LIMITED
BY VERY DRY AIR SHOWN ON 00Z AREA RAOBS/LIMITED MSTR RETURN INTO THE
PLAINS DISRUPTED BY THE CIRCULATION ARND ISAAC.

TODAY...ALTHOUGH THE SFC HI PRES CENTER IS FCST TO RETREAT INTO FAR
WRN QUEBEC BY 00Z MON...LINGERING SFC-H85 RDG AXIS EXTENDING WWD FM
THE HI CENTER INTO THE UPR LKS TO THE N OF ISAAC WL BRING ANOTHER
DRY DAY TO UPR MI. MIXING TO H85 ON NAM FCST SDNGS YIELDS HI TEMPS
80 TO 85 AWAY FM MODERATION MAINLY DOWNSTREAM OF LK MI IN LLVL SSE
FLOW. WITH THIS MIXING DEPTH...SFC DEWPTS SHOULD DIP AS LO AS THE
UPR 40S OVER THE INTERIOR W AND FAR E AWAY FM LK MI MODERATION...
SETTING UP MIN RH ARND 30 PCT. FORTUNATELY FOR FIRE WX CONCERNS...
THE PRES GRADIENT IS NOT FCST TO TIGHTEN SGNFTLY UNTIL LATER IN THE
DAY AND MAINLY OVER THE W CLOSER TO APRCHG COLD FNT MOVING INTO WRN
MN LATE IN THE DAY. BUT WITH WIND GUSTS UP TO 15 TO 20 MPH AND
EXPECTED CONDITIONS/RECENT DRYNESS... WL CONTINUE TO MENTION
ELEVATED RISK OF WILDFIRES IN HWO.

TNGT...CLOSED/OCCLUDED LO PRES IS PROGGED TO DRIFT TO JUST NW OF LK
WINNIPEG BY 12Z MON. ATTENDANT COLD FNT PRECEDED BY RELATIVELY
NARROW RIBBON OF WARM CONVEYOR BELT MSTR LIMITED BY DRYNESS OF
AIRMASS IN THE PLAINS AS INDICATED ON 00Z RAOBS IS FCST TO APRCH WRN
LK SUP TOWARD 12Z MON. ONE POSITIVE FOR POPS IS RIBBON OF STRONGER
H3 WINDS THAT IS FCST TO DVLP OVER THE PLAINS INTO THE UPR LKS WELL
TO THE S OF MAIN CLOSED LO TO THE N. VARIOUS MODELS...INCLUDING THE
00Z GFS/NAM...SHOW AN 80KT H3 JET MAX WITHIN THIS FLOW/SHRTWV/SOME
H4-2 DVGC APRCHG THE WRN ZNS LATE. BUT GIVEN THE LIMITED MSTR RETURN
THAT MAINTAINS CIN ON FCST SDNGS DESPITE FAIRLY STEEP H7-5 LAPSE
RATES...PASSAGE OF MOST SGNFT DEEP LYR QVECTOR CNVGC TO THE N CLOSER
TO MAIN CLOSED LO...TREND FOR SLOWER EWD MOTION OF COLD FNT TO THE
E...AND ARRIVAL OF SHRA AT MIN HEATING TIME...TENDED TO FOLLOW THE
DRIER 00Z GFS/CNDN MODELS TO RESTRICT POPS TO THE FAR WRN COUNTIES
MAINLY AFT 09Z. THE GFS IS ON THE DRIER SIDE EVEN WITH APRCHG JET
MAX...SO SUSPECT THESE NEGATIVES WL OUTWEIGH IMPACT OF ANY
DISTURBANCE THAT MIGHT APRCH FM THE WSW. EXPECT THE WARMEST MIN
TEMPS OVER THE W NEAR LK SUP UNDER SHARPER PRES GRADIENT AND WHERE
MOISTENING WL BE MOST PRONOUNCED/S WIND WL DOWNSLOPE.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 429 AM EDT SUN SEP 2 2012

THROUGH MUCH OF THE LONG TERM...WEATHER WILL BE IMPACTED BY A CLOSED
500MB LOW CURRENTLY OVER ALBERTA. THE LOW WILL MOVE TO MANITOBA BY
12Z MON...WHERE IT WILL SIT UNTIL TUE NIGHT WHEN ADDITIONAL ENERGY
MERGES WITH THE SYSTEM. THE LOW WILL THEN SPIN ACROSS FAR NRN
ONTARIO FROM LAKE WED INTO FRI...AND MODELS AGREE WELL ON
THIS...WITH MUCH REDUCED MODEL AGREEMENT /AND THEREFOR FORECAST
CONFIDENCE/ THROUGH SAT AS MODELS DIFFER CONSIDERABLE WITH HOW FAST
TO MOVE HAVE THE LOW EXIT THE REGION.

MONDAY...MODELS SHOW A WEAKENING COLD FRONT MOVING THROUGH BETWEEN
ROUGHLY 18Z MON AND 06Z TUE...DURING PEAK HEATING. WITH 850MB TEMPS
AROUND 18C...HIGH TEMPS ARE FORECAST TO BEE IN THE UPPER 70S AND
80S. THESE WARM SFC TEMPS...COMBINED WITH COOLING MID/UPPER LEVELS
AND STEEPENING LAPSE RATES...WILL LEAD TO INCREASED INSTABILITY WITH
LITTLE TO NO CIN. MODEL GUIDANCE AND FORECAST SOUNDINGS INDICATED
POTENTIAL FOR 1500-2000J/KG OF CAPE OVER MAINLY CENTRAL AND WRN
UPPER MI DURING THE AFTERNOON AND EARLY EVENING. UNIDIRECTIONAL
WINDS INCREASE STEADILY WITH HEIGHT...LEADING TO 35-40KTS OF 0-6KM
SHEAR /0-1 KM SHEAR OF 15KTS OR LESS/. MID LEVELS AROUND 500MB LOOK
FAIRLY DRY...WITH AMPLE LOW LEVEL MOSTURE. ALL THIS LOOKS TO ADD UP
TO A MODERATE POTENTIAL FOR STRONG TO SEVERE STORMS WITH WINDS BEING
THE PRIMARY THREAT...AND HAIL BEING A SOMEWHAT LOWER SECONDARY
THREAT. WOULD EXPECT STORM COVERAGE/INTENSITY TO DIMINISH AFTER LOSS
OF SFC HEATING.

TUESDAY...MODELS SHOW ANOTHER COLD FRONT MOVING THROUGH THE CWA.
INSTABILITY LOOKS LOWER THAN MONDAY WITH WEAKER UNIDIRECTIONAL FLOW.
THUS...IF THUNDERSTORMS DEVELOP THEY WILL BE WEAKER...WITH MAYBE
SOME STRONGER STORMS POSSIBLE IN THE AFTERNOON. WILL CONTINUE
SHOWING CHANCE POPS FOR TUE AFTERNOON/EVENING.

WEDNESDAY...A STRONGER PUSH OF 500MB HEIGHT FALLS MOVES OVER THE
AREA WED AS AN ADDITIONAL PIECE OF UPPER ENERGY WRAPS AROUND THE
UPPER LOW. THIS BRINGS ANOTHER...ALBEIT MORE DEFINED...COLD FRONT
THROUGH THE CWA. ALHOUGH SHEAR LOOKS A BIT STRONGER THAN
TUE...INSTABILITY SHOULD AGAIN BE LOWER. SO MAYBE A STRONGER
THUNDERSTORMS OR TWO COULD OCCUR WHERE PRECIP DEVELOPS.

THURSDAY AND FRIDAY...WE WILL TRANSITION TO BEING MORE ON THE BACK
SIDE OF THE UPPER LOW THURSDAY AFTERNOON AFTER THE MAIN UPPER TROUGH
PASSES THROUGH. SFC HIGH PRESSURE WILL BE PUSHING IN FROM THE W
THROUGH FRI...LEADING TO NW FLOW AND MUCH COOLER AIR MOVING INTO THE
REGION. 850MB TEMPS THU AFTERNOON SHOULD BE AROUND 7C...THEN DOWN TO
AROUND 5C BY FRIDAY AFTERNOON. RESULTING HIGH TEMPS LOOK TO BE IN
THE 60S TO LOW 70S.

SATURDAY...AS PREVIOUSLY MENTIONED...MODEL AGREEMENT AND FORECAST
CONFIDENCE DECREASE SHARPLY LATE FRI INTO SAT AS MODELS DIFFER WITH
HOW FAST TO USHER AWAY THE UPPER LOW. JUST WENT WITH A CONSENSUS OF
GUIDANCE FOR NOW.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 123 AM EDT SUN SEP 2 2012

EXPECT VFR CONDITIONS THIS FCST PERIOD AS DRY HIGH PRESSURE
REMAINS OVER/NEAR THE UPPER GREAT LAKES.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 AM EDT SUN SEP 2 2012

EXPECT LIGHT SSE WINDS THIS MORNING UNDER HI PRES RIDGE AXIS TO
INCREASE LATER TODAY INTO MON UNDER SHARPENING PRES GRADIENT AS THE
HI MOVES TO THE E AND A COLD FRONT APPROACHES FROM THE W. ARRIVAL OF
WEAKER PRES GRADIENT LATER ON MON INTO WED WILL BRING A RETURN OF
WINDS UNDER 15 KTS. THE PASSAGE OF A STRONGER COLD FRONT ON WED
SHOULD BRING A RETURN OF STRONGER W-NW WINDS TO 20 OR PERHAPS 25 KTS
FOR LATER WED THRU THU.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...KC
LONG TERM...TITUS
AVIATION...VOSS
MARINE...KC

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

124 AM EDT SUN SEP 2 2012

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 407 PM EDT SAT SEP 1 2012

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 407 PM EDT SAT SEP 1 2012

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 123 AM EDT SUN SEP 2 2012

EXPECT VFR CONDITIONS THIS FCST PERIOD AS DRY HIGH PRESSURE
REMAINS OVER/NEAR THE UPPER GREAT LAKES.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EDT SAT SEP 1 2012

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...ROLFSON

AREA FORECAST DISCUSSION...UPDATED AVIATION

NWS ST LOUIS MO

1207 AM CDT SUN SEP 2 2012

.UPDATE...
ISSUED AT 853 PM CDT SAT SEP 1 2012

GKS

.SHORT TERM...
ISSUED AT 347 PM CDT SAT SEP 1 2012
(TONIGHT AND SUNDAY)

BRITT

.LONG TERM...
ISSUED AT 347 PM CDT SAT SEP 1 2012
(SUNDAY NIGHT THROUGH NEXT SATURDAY)

BRITT

.AVIATION...
ISSUED AT 1145 PM CDT SAT SEP 1 2012

REMAINS OF ISSAC IS CENTERED APPROXIMATELY 30 MILES SOUTHEAST KLSX
AND CONTINUES TO MOVE EASTWARD. LIGHT RAIN CONTINUES TO ROTATION
AROUND THE LOW CENTER WITH THE LARGER BAND ROTATING OVER PARTS OF
EASTERN ILLINOIS THORUGH SOUTHEAST MISSOURI. THE LOW CENTER IS
FORECAST TO MOVE INTO SOUTHEAST ILLINOIS BY 1200 UTC SUNDAY
MORNING. WILL CONTINUE WITH LOW CEILINGS AND OCCASIONAL VSBYS OF 3
TO 5 MILES IN LIGHT RAIN AND LIGHT FOG THROUGH SUNDAY MORNING.

SPECIFICS FOR KSTL...CEILINGS WILL CONTINUE TO LOWER OVER MUCH OF
EASTERN MISSOURI BETWEEN 0600 AND 0800 UTC. EXPECT CEILING TO DROP
BELOW 010 KFT AND VISIBILITIES WILL OCCASIONALLY DROP 3 TO 5 MILES
IN LIGHT RAIN AND LIGHT FOG. WINDS WILL BECOME NORTH NORTHEAST 10
TO 12 KTS AFTER 0600 UTC. LOW CEILINGS WILL BEGIN TO LIFT AFTER
1500-1600 UTC TIME PERIOD WITH VISIBILITIES ABOVE 6 MILES.
ISOLATED TO WIDELY SCATTERED SHOWERS POSSIBLE DURING DAY ON SUNDAY
OVER STL.

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

WFO LSX

AREA FORECAST DISCUSSION...UPDATED

NWS MEMPHIS TN

1140 PM CDT SAT SEP 1 2012

.UPDATE...
UPDATED FOR AVIATION.

.PREV DISCUSSION... /ISSUED 1120 PM CDT SAT SEP 1 2012/

DISCUSSION...

SEVERE WEATHER EVENT WINDING DOWN ACROSS THE FORECAST AREA BUT NOT
COMPLETELY DISAPPEARING. ENERGY FROM ISAAC WILL CONTINUE THE
THREAT OF THUNDERSTORMS THROUGH THE NIGHT WITH AN ISOLATED SEVERE
STORM POSSIBLE.

THE REMNANT LOW FROM ISAAC NEAR THE MO/IL BORDER WILL TRACK INTO
THE OH VALLEY SUNDAY. AN ASSOCIATED UPPER TROUGH WILL DRAG THROUGH
THE AREA SUNDAY CONTINUING THE HIGH CHANCES OF SHOWERS AND
THUNDERSTORMS. EXPECT STRONG STORMS ON SUNDAY.

SWC

PREV DISCUSSION... /ISSUED 331 PM CDT SAT SEP 1 2012/

DISCUSSION...19Z SURFACE ANALYSIS CENTERS THE REMNANTS OF ISAAC
JUST NORTH OF COLUMBIA MISSOURI. THERE HAS BEEN A BREAK IN THE
SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE MID SOUTH FROM LATE
THIS MORNING THROUGH MID AFTERNOON AS A DRY SLOT /INDICATED BY
WATER VAPOR SATELLITE TRENDS/ HAS BUILT IN TO ARKANSAS AND MUCH OF
THE MID SOUTH. THUNDERSTORMS ARE ONLY BEGINNING TO DEVELOP ONCE
AGAIN UP ACROSS EXTREME NORTHWEST ARKANSAS IN ASSOCIATION WITH AN
APPROACHING SHORTWAVE ASSOCIATED WITH THE REMNANTS OF ISAAC.
TEMPERATURES AS OF 3 PM CDT ARE IN THE MIDDLE 80S TO LOWER 90S
ACROSS THE FORECAST AREA. STRONG TO SEVERE THUNDERSTORM POTENTIAL
TONIGHT AND CONVECTIVE CHANCES INTO NEXT WEEK ARE THE MAIN
FORECAST CHALLENGES FOR THIS AFTERNOON/S FORECAST ISSUANCE.

SHORT TERM...(TONIGHT THROUGH TUESDAY)...LATEST SHORT TERM
MODELS...ESPECIALLY THE HRRR AND THE 12Z WRF SUGGEST THE
RELATIVELY RAIN FREE CONDITIONS CURRENTLY OCCURRING ACROSS THE MID
SOUTH WILL COME TO AN END THIS EVENING AS ANOTHER SHORTWAVE
ROTATING AROUND THE REMNANTS OF ISAAC MOVES ACROSS THE LOWER
MISSISSIPPI VALLEY TONIGHT. DAYTIME INSTABILITY /SURFACE BASED
CAPE VALUES AVERAGING BETWEEN 2000-3500 J/KG...LI/S BETWEEN -5 TO
-6/ AND STEEP LOW LEVEL LAPSE RATES HAVE RESULTED IN THE
DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
ARKANSAS...FROM NEAR WALNUT RIDGE BACK THROUGH CENTRAL AND WEST
CENTRAL ARKANSAS. AT THIS TIME BELIEVE THIS ACTIVITY WILL
GRADUALLY INCREASE IN COVERAGE AS IT MOVES ACROSS THE MID SOUTH
TONIGHT...ESPECIALLY ALONG AND NORTH OF I-40. THUS...INCREASED
POPS ACROSS THE ABOVE MENTIONED AREAS. A FEW STRONG TO PERHAPS
ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE TONIGHT AS THIS
SHORTWAVE MOVES THROUGH THE MID SOUTH. DAMAGING WINDS WILL BE THE
MAIN THREAT FOR ANY THUNDERSTORM THAT REACHES SEVERE LIMITS. A
TROPICAL AIR MASS COMBINED WITH PRECIPITABLE WATER VALUES ABOVE 2
INCHES SUGGESTS THE POTENTIAL FOR LOCALIZED FLASH FLOODING FROM
HEAVY RAINFALL WITHIN THUNDERSTORMS.

SHORT TERM MODELS INDICATE THE REMNANTS OF ISAAC WILL GRADUALLY
MOVE EAST SOUTHEAST TO THE OHIO AND TENNESSEE VALLEYS FOR SUNDAY
THROUGH TUESDAY. AS A RESULT...A CONTINUED CHANCE FOR SHOWERS AND
THUNDERSTORMS WILL PERSIST BUT GRADUALLY DECREASE THROUGH THE
REMAINDER OF THE PERIOD. A STRONG THUNDERSTORM OR TWO CONTAINING
HEAVY RAINFALL AND GUSTY WINDS WILL ALSO BE POSSIBLE ON SUNDAY
AFTERNOON.

LONG TERM...(WEDNESDAY THROUGH SATURDAY)...12Z GFS/ECMWF LONG
RANGE MODELS INDICATE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL
PERSIST ACROSS THE AREA THROUGHOUT THE PERIOD AS ANOTHER COLD
FRONT DROPS INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY NIGHT AND
THEN STALLS OUT ACROSS THE AREA INTO NEXT WEEKEND. KEPT
PRECIPITATION CHANCES ON THE LOW END FOR THE TIME BEING AS THERE
ARE SOME TIMING/COVERAGE DIFFERENCES BETWEEN THE LONG TERM MODEL
SOLUTIONS.

CJC

.AVIATION...
06Z TAFS

PRIMARY FORECAST CONCERN IS OVERNIGHT SHRA/TSRA IN THE MOIST AND
MODERATELY UNSTABLE NIGHTTIME TROPICAL AIRMASS. ALL BUT JBR APPEAR
TO BE SUFFICIENTLY UNSTABLE FOR TSRA REDEVELOPMENT. BEST TS CHANCE
APPEARS TO BE AT MKL...IN CLOSER TO PROXIMITY TO ONE OF THE
NUMEROUS BAROCLINIC BANDS ROTATING AROUND THE SOUTHERN PERIPHERY
OF ISAAC/S REMNANT LOW.

BEST TSRA CHANCE FOR SUNDAY APPEARS TO BE MKL AND TUP. MEM AND JBR
SHOULD SEE MORE MARGINAL...NONZERO TS CHANCES.

PWB

.PRELIMINARY POINT TEMPS/POPS...
MEM 74 93 76 94 / 60 40 40 20
MKL 72 89 72 89 / 70 60 50 30
JBR 75 90 72 93 / 70 50 30 20
TUP 74 90 73 92 / 50 40 50 30

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

AREA FORECAST DISCUSSION

NWS MEMPHIS TN

1120 PM CDT SAT SEP 1 2012

.DISCUSSION...

SWC

.PREV DISCUSSION... /ISSUED 331 PM CDT SAT SEP 1 2012/

CJC

.AVIATION...
18Z TAFS
STARTING TO SEE ANOTHER ROUND OF SHOWERS/STORMS BEGIN TO
DEVELOP ACROSS THE MIDSOUTH AS TEMPERATURES CLIMB INTO THE UPPER
80S. SHOWERS WILL BE HIT AND MISS THROUGH MOST OF THE
AFTERNOON...MUCH LIKE YESTERDAY. AROUND 00-04Z A BAND OF POSSIBLY
STRONGER SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP NEAR JBR
TO LITTLE ROCK AND MOVE TO THE EAST. TRIED TO TIME THIS UN-
DEVELOPED LINE BY ADDING VCTS TO JBR...THEN MEM AND MKL. HOWEVER
TIMING OF THIS FEATURE WILL BECOME MUCH MORE CERTAIN AFTER...OR
EVEN IF IT DEVELOPS. WILL AMEND WHEN THERE IS SOMETHING MORE
CONCRETE TO TRACK. STRONG WIND AND BRIEF IFR VISIBILITY DUE TO
HEAVY RAIN CAN BE EXPECTED. OTHERWISE...EXPECT PRECIPITATION
INTENSITY AND COVERAGE TO DIMINISH BY 06Z...WITH MVFR TO IFR LOW
CLOUDS DURING TH EARLY MORNING HOURS.

.PRELIMINARY POINT TEMPS/POPS...
MEM 75 93 76 94 / 60 40 40 20
MKL 72 89 72 89 / 70 60 50 30
JBR 75 90 72 93 / 70 50 30 20
TUP 74 90 73 92 / 50 40 50 30

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&

AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

1130 PM CDT SAT SEP 1 2012

.UPDATE...

DRY AIR FROM THE NORTHEAST HAS ERODED THE PRECIPITATION ACROSS FAR
SOUTHEAST WISCONSIN AND SOUTHERN LAKE MICHIGAN. THE LATEST NAM AND
THE HRRR KEEP US DRY THROUGH THE NIGHT...WITH SOME LIGHT
PRECIPITATION SUNDAY MORNING BEFORE NOON.. WILL TRIM BACK THE
CHANCES OF RAIN TONIGHT A LITTLE WITH ONLY THE FAR SOUTHEAST TIP IN
A SLIGHT CHANCE OF SHOWERS.

.AVIATION/06Z TAFS/...

MVFR CIGS SHOULD EXPAND ESPECIALLY SOUTHEAST. SOME MVFR FOG ALSO
EXPECTED WITH THE HIGHER DEWPOINTS SOUTHEAST AND FAR SOUTH CENTRAL.
THE LATEST NAM AND THE HRRR KEEP US DRY THROUGH THE NIGHT.

LOW WILL TRACK ACROSS SOUTHERN ILLINOIS TONIGHT THEN REACH FAR
SOUTHERN INDIANA SUNDAY EVENING.

.PREV DISCUSSION... /ISSUED 302 PM CDT SAT SEP 1 2012/

SUNDAY NIGHT...FORECAST CONFIDENCE IS HIGH.

MONDAY AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM.

WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM TO HIGH.

THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS LOW TO MEDIUM.

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM CDT SUNDAY FOR LMZ646.

UPDATE...HENTZ
TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR
SUNDAY NIGHT THROUGH SATURDAY...DAVIS

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

722 AM EDT SUN SEP 2 2012

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM EDT SUN SEP 2 2012

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 429 AM EDT SUN SEP 2 2012

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 721 AM EDT SUN SEP 2 2012

ALTHOUGH A FEW -SHRA MAY ARRIVE AT IWD/CMX LATE TNGT AHEAD OF AN
APRCHG COLD FNT...EXPECT VFR CONDITIONS THRU THIS FCST PERIOD WITH A
PERSISTENCE OF PLENTY OF LLVL DRY AIR ASSOCIATED WITH HI PRES RDG
STRETCHING FM QUEBEC INTO THE UPR GRT LKS. SOME LLWS MAY IMPACT IWD
TNGT AS A LLJ DEVELOPS UNDER THE SHARPENING PRES GRADIENT BTWN THE
DEPARTING HI AND THE APRCHG FNT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 AM EDT SUN SEP 2 2012

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC

AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

958 AM CDT SUN SEP 2 2012

.DISCUSSION...
MORNING UPDATE FOCUSED ON PRECIP AND TODAYS HIGHS. CURRENT RADAR
SHOWERS OVER NORTHWEST MINNESOTA ALONG WITH SOME HIGH BASED TSTMS.
TO THE WEST...RADAR ECHOES APPEAR TO BE MID CLOUDS. MOST ACTUAL
RAIN REPORTS HAVE BEEN BETWEEN GRAND FORKS AND ROSEAU. COLD FRONT
WORKING ITS WAY INTO DVL REGION HOWEVER COOLER AIR STILL BACK IN
SASKATCHEWAN.

CLOUD COVER IS INHIBITING MUCH RISE IN TEMPERATURES AND A BLEND OF
PREV BLEND WITH MOST RECENT RUC GUIDANCE DROPPED TEMPS A GOOD 7
DEG IN GFK...AND DID A DECENT JOB REFLECTING CLOUD COVER ELSE
WHERE. THUS SOME SIGNIFICANT CHANGES TO DAYTIME HIGHS WHERE
THICKEST CLOUDS AND/OR RAIN IS OCCURRING. MADE MINOR ADJUSTMENTS TO
POPS (INCREASED TO 40 PER CENT AREAL COVERAGE FOR AFOREMENTIONED
AREAS OF RAIN) THROUGH 09Z. CAN EXPECT SCATTERED SHOWERS AND
ISOLATED STORMS TO CONTINUE THROUGH MORNING...WITH SCATTERED
STORMS IN AFTN. STILL TO EARLY TO TELL IF WE WILL SEE SEVERE
STORMS LATE THIS AFTN...BUT THE CLOUD COVER AND UPPER CAP WILL
CERTAINLY TRY TO PUT THE DAMPER ON ANY SEVERE DEVELOPMENT.
CONFIDENCE IS LOW.

.AVIATION...
COLD FRONT WILL SLOWLY MOVE THROUGH FA TODAY. WILL STILL SEE SOME
GUSTY S WINDS THIS AM AHEAD OF FRONT. SPOTTY SHRA/TSRA WILL SPREAD
FROM NW-SE ACROSS FA WITH FROPA HOWEVER CIGS SHOULD REMAIN VFR.
COULD SEE SOME STRONGER STORMS THIS EVENING MAINLY ACROSS WEST
CENTRAL MN.

.PREV DISCUSSION... /ISSUED 235 AM CDT SUN SEP 2 2012/

DISCUSSION...
FORECAST CHALLENGE CONCERNS PCPN CHANCES AND TEMPERATURES. TOSSED
GFS LOW LEVEL MOISTURE FIELDS WHICH ARE WAY TOO MOIST OTHERWISE
MODELS IN FAIRLY GOOD AGREEMENT AND WILL USE BLEND FOR FORECAST.

COLD FRONT MOVING INTO CENTRAL DAKOTAS AND WILL PROPAGATE SLOWLY
EAST TODAY BEING FAIRLY PARALLEL TO UPPER FLOW. WITH STRONG CAP
UPSTREAM BAND OF SHRA/TSRA LOOKS TO BE ALONG AND BEHIND BOUNDARY.
WITH SLIGHTLY SLOWER FROPA INDICATED BY MODELS AND CURRENT PCPN
TRENDS WILL PUSH POPS BACK TO THE WEST TODAY. MOIST AXIS FAIRLY
NARROW AND UPSTREAM COVERAGE SUPPORTS CURRENT CHANCE POPS. FAIRLY
RESPECTABLE CAP HOLDS IN MOST OF DAY HOWEVER IF ANY CONVECTION CAN
BREAK CAP BASED ON CONVECTIVE PARAMETERS COULD SEE A FEW STRONG
STORMS FROM SOUTHERN VALLEY INTO WEST CENTRAL/NORTH CENTRAL MN.
TEMPERATURES MAY BE TRICKY TODAY DEPENDENT ON CLOUD COVER. COLUMN
REMAINS QUITE WARM AND AHEAD OF PCPN BAND LOOKS TO BE MOSTLY CI SO
WITH WARM START WILL NOT TAKE MUCH TO GET INTO THE 80S.

BEGINNING OF NEXT WEEK WILL FEATURE BROAD MID LEVEL
TROUGHING...ALMOST ZONAL ACROSS NORTHERN TIER OF STATES. SECONDARY
COLD FRONT DROPS THROUGH FA MONDAY. TIME SECTIONS REVEAL THAT COLUMN
LOOKS QUITE DRY AND NOT MUCH UPPER SUPPORT SO VERY LOW CONFIDENCE ON
ANY PCPN OCCURRING WITH FROPA. DID INSERT SOME SLIGHT CHANCE POPS
ACROSS SW FA MAINLY FOR COORDINATION PURPOSES. COLUMN COOLS SOMEWHAT
BUT STILL LIKELY TO SEE ABOVE AVERAGE TEMPERATURES.

TUESDAY LOOKS QUIET WITH ANOTHER COOLING FRONT DROPPING THROUGH
TUESDAY NIGHT. ALTHOUGH MOISTURE STILL MARGINAL THIS BOUNDARY HAS
MORE SUPPORT FROM THE MID LEVELS SO HAVE EXPANDED POPS.

LONG TERM...WEDNESDAY THROUGH SUNDAY
CONSISTENT MODEL TO MODEL RUN LEADS TO A DECENT HANDLE ON THE
EXTENDED FORECAST. AT THE START OF THE PERIOD WE SEE A WELL
ADVERTISED SHORT WAVE MOVING ACROSS SOUTHERN CANADA IN BROAD
NORTHWEST FLOW. SHORTWAVE TROUGH CROSSES THE AREA LATE WEDNESDAY
INTO THURSDAY WITH VERY LOW THREAT OF SHRA. THICKNESS FALL WITH 850
TEMPS FALLING INTO THE 7 TO 10C RANGE OVER THE NORTHEAST CWFA AND 10
TO 15C SOUTHWEST MAY MAKE FOR A DECENT EARLY FALL TEMPERATURE
GRADIENT. MODEL CONTINUITY CONTINUES IN FAIR AGREEMENT AS 00Z ECMWF
COMING MORE IN LINE WITH 00Z GFS/DGEX/GEM AS THEY MOVE THE WAVE
THROUGH LATE THURSDAY INTO FRIDAY. WITH A WEAK SURFACE REFLECTION
SOME SHRA/TSRA LIKELY ALONG AND BEHIND BOUNDARY. ECMWF SLOWER THAN
OTHER OPERATIONAL MODELS FOR END OF THIS EXTENDED PERIOD. AS THE
COLUMN DRIES OUT AND WARMS UP UNDER BUILDING UPPER HEIGHTS
TEMPERATURES BEGIN TO WARM BACK ABOVE EARLY SEPTEMBER MEANS.
ALLBELNDS SEEMS TO CAPTURE THE CONSENSUS OF THE MODELS MOST IN
AGREEMENT AND HAVE FOLLOWED CLOSELY.

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$
SPEICHER/VOELKER

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

617 AM CDT SUN SEP 2 2012

.SHORT TERM...TODAY THROUGH WEDNESDAY
300 AM CDT SUN SEP 2 2012

THE MAIN FOCUS IN THE SHORT TERM IS ON THE PRECIPITATION CHANCES
MONDAY INTO WEDNESDAY.

CURRENTLY...CLEAR SKIES ARE THE RULE THROUGHOUT MUCH OF THE REGION
WITH THE CIRRUS FROM ISAAC DRIFTING EAST ACROSS SOUTHERN
WISCONSIN/NORTHERN ILLINOIS AND THE NEXT SYSTEM STILL WELL OFF TO
THE WEST IN EASTERN MONTANA. DRY LOW LEVEL AIR AND LIGHT WINDS
ARE IN PLACE DUE TO A RIDGE OF HIGH PRESSURE THAT EXTENDS ACROSS
SOUTHEAST CANADA THROUGH THE GREAT LAKES.

ANOTHER PLEASANT DAY IS ON TAP FOR THE UPPER MISSISSIPPI RIVER
VALLEY AS THE WESTERN PERIPHERY OF THE SURFACE RIDGE AXIS REMAINS
ACROSS THE REGION WITH THE NEXT SYSTEM MOVING ACROSS THE DAKOTAS.
WITH THIS FRONT APPROACHING FROM THE WEST AND THE RIDGE AXIS
DRIFTING EAST...THE LOW LEVEL WIND FLOW WILL BECOME MORE SOUTHERLY
AND WILL HELP TO USHER IN SOME SLIGHTLY WARMER AIR INTO THE
REGION. SKIES WILL MAINLY BE SUNNY...THOUGH 02.00Z NAM/GFS BUFKIT
SOUNDINGS ARE SHOWING SOME MOISTURE AROUND 4KFT THAT COULD LEAD TO
SOME FAIR WEATHER CU DEVELOPING IN THE LATE MORNING/AFTERNOON
HOURS.

THE 02.00Z NAM/GFS/GEM/ECMWF ARE ALL IN DECENT AGREEMENT WITH THE
TIMING OF THE FRONT AND CONVECTION ENTERING THE REGION EARLY
MONDAY MORNING TOWARD DAYBREAK ACROSS WESTERN WISCONSIN AND
SOUTHERN MINNESOTA/NORTHERN IOWA. THIS FRONT WILL MOVE THROUGH
FROM MONDAY MORNING INTO THE EVENING AND DECAY AS IT TRACKS EAST.
DESPITE THIS WEAKENING LOW LEVEL FORCING...A MID LEVEL SHORTWAVE
TROUGH WILL BE PROPAGATING THROUGH AND PROVIDE ENOUGH LIFT TO WORK
WITH THE UNCAPPED INSTABILITY AHEAD OF THE FRONT TO PRODUCE SOME
SHOWERS AND THUNDERSTORMS...PARTICULARLY ACROSS WESTERN WISCONSIN
IN THE AFTERNOON. THE 02.00Z NAM IS A LITTLE STRONGER WITH ITS
0-3KM SHEAR COMPARED TO THE 02.00Z GFS WHICH KEEPS THE BETTER
SHEAR BEHIND THE FRONT. A FEW STRONG STORMS STILL CAN NOT BE RULED
OUT GIVEN THE INSTABILITY...FORCING AND IDEAL TIMING OF THE
FRONTAL PASSAGE IN THE MIDDLE OF THE AFTERNOON IN WESTERN
WISCONSIN THOUGH IT SHOULD NOT BE A WIDESPREAD EVENT.

AFTER THIS FEATURE PASSES...THE FORECAST BECOMES A BIT MORE
MUDDLED GOING INTO MID WEEK AS DIFFERENCES ARISE BETWEEN THE
GUIDANCE. MONDAY NIGHT INTO TUESDAY APPEARS TO BE THE BIGGEST
CHALLENGE WITH THE 02.00Z NAM KEEPING THE LOW LEVEL MOISTURE
TRANSPORT FIXED TO THE SOUTH WITH RIDGING OVERHEAD WHILE THE
02.00Z GFS IS STRONGER WITH IT AND SPREADS PRECIPITATION ACROSS
THE REGION THROUGH MUCH OF THE DAY...WHICH IS LIKELY OVERDONE.
STILL THINK THAT A MENTION OF PRECIPITATION IS WARRANTED ON
TUESDAY...BUT CONFIDENCE IS NOT HIGH ENOUGH TO KEEP THE 40-50
PERCENT CHANCES IN THERE. THE NAM/GFS/ECMWF DO APPEAR TO DROP
ANOTHER WEAK COLD FRONT DOWN ACROSS CENTRAL WISCONSIN TUESDAY
NIGHT BEFORE THE MAIN SHOW ARRIVES ON WEDNESDAY AS THE COLD FRONT
COMES THROUGH THAT WILL PUSH TEMPERATURES BACK DOWN TO NORMAL. THE
ASSOCIATED DEEP MID LEVEL TROUGH WILL SPLIT A SHORTWAVE TROUGH OFF
OF IT ON WEDNESDAY AS THE COLD FRONT COMES THROUGH. THIS APPEARS
TO BE THE BEST COMBINATION OF FORCING...MOISTURE AVAILABILITY AND
INSTABILITY OVER THE NEXT FEW DAYS AND THUS WARRANTS THE HIGHEST
CHANCES FOR PRECIPITATION INTO THE AFTERNOON.

.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY
300 AM CDT SUN SEP 2 2012

COOLER AIR WILL MOVE INTO THE REGION BEHIND THE COLD FRONT THAT
COMES THROUGH ON WEDNESDAY WITH NORTHWESTERLY FLOW ALOFT THAT WILL
PERSIST INTO NEXT WEEKEND. TEMPERATURES WILL BE AT OR JUST BELOW
SEASONAL VALUES WITH HIGHS IN THE LOW TO MID 70S. THE NEXT CHANCES
FOR PRECIPITATION WILL COME ON FRIDAY AS A MID LEVEL TROUGH DIVES
TO THE SOUTH ACROSS THE NORTHERN PLAINS/UPPER MISSISSIPPI RIVER
VALLEY. THE 02.00Z ECMWF APPEARS TO BE THE ODD MODEL OUT AT THIS
POINT WITH KEEPING A SECONDARY CLOSED LOW DROPPING DOWN ON
SATURDAY WHILE THE 02.00Z GFS/GEM ARE FASTER WITH BUILDING A RIDGE
IN BY SATURDAY MORNING. THE BETTER FORCING WITH THIS SYSTEM
APPEARS TO GO TO THE SOUTH WHERE A SURFACE LOW SPINS UP ACROSS THE
SOUTHERN PLAINS AND HEADS EAST TOWARD THE OHIO RIVER VALLEY.

.AVIATION...TODAY AND TONIGHT
617 AM CDT SUN SEP 2 2012

HIGH PRESSURE EXTENDING FROM LAKE SUPERIOR INTO SOUTHERN MN KEEPING
SKIES MOSTLY CLEAR ACROSS THE AREA THIS MORNING. EAST FLOW AND
REMNANTS OF ISAAC OVER IL BRINGING A FEW MVFR LEVEL STRATOCUMULUS
INTO FAR SOUTHERN WI/NORTHEAST IA. RAP MODEL INDICATING SOME
INCREASE IN LOWER LEVEL MOISTURE WHICH MAY PRODUCE FEW-SCT020-025 AS
FAR NORTH AS KLSE THROUGH THIS MORNING. AS SUCH...ADDED FEW022 IN
THE KLSE FROM 13-17Z. MODEL SOUNDINGS THEN SHOW MIXING/DRYING
THROUGH THE LOWEST 3-4KFT DISSIPATING THIS CLOUD. FOR THE REST OF
THE DAY...MAY SEE A FEW DAYTIME HEATING CUMULUS FLOATING AROUND
WITH BASES IN THE 4-5KFT RANGE...THEN DISSIPATING BY SUNSET. NEXT
CONCERN WILL BE INCOMING COLD FRONT FROM MN LATE TONIGHT. EXPECTING
AN INCREASE IN ALTOCUMULUS WITH BASES AOA 12KFT IN ADVANCE OF THE
FRONT REACHING THE KRST/KLSE TAF SITES AFTER 06Z. ANY SHRA/TS
ACTIVITY WITH THE FRONT EXPECTED TO REMAIN NORTHWEST OF THE TAF
SITES THROUGH 12Z. SOME MODEL GUIDANCE SUGGESTING VALLEY FOG
POTENTIAL AT KLSE TOWARD MORNING...BUT FEEL THIS IS OVERDONE AND
WILL NOT BE REALIZED DUE TO AN INCREASE IN MID-CLOUD WHICH WILL
INHIBIT NEEDED RADIATIONAL COOLING. ANOTHER NEGATIVE FACTOR IN FOG
FORMATION WILL BE INCREASING PRESSURE GRADIENT/STIRRING WINDS IN
ADVANCE OF THE COLD FRONT. WILL HAVE TO WATCH SHRA/TS POTENTIAL
FOR MONDAY. APPEARS RIGHT NOW THAT THE HIGHEST POTENTIAL FOR
CONVECTION WILL BE NORTH OF TH TAF SITES...BUT NEEDS TO BE WATCHED
CLOSELY. WILL PASS THIS CONCERN ONTO THE DAYSHIFT FOR FURTHER
ASSESSMENT.

.ARX WATCHES/WARNINGS/ADVISORIES...
300 AM CDT SUN SEP 2 2012

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DAS

AREA FORECAST DISCUSSION

NWS DENVER CO

259 PM MDT SUN SEP 2 2012

.SHORT TERM...DURING THE NEXT FEW HOURS SHOULD SEE A STEADY
INCREASE IN SHOWER/T-STORM FORMATION OVER THE MTNS AND HIGH
VALLEYS. THIS INCREASE IN CONVECTION IS IN RESPONSE TO A REGION
OF MID/UPPER LEVEL LIFT/INSTABILITY GENERATED ON THE NOSE OF
40-50KT 300-500MB JET MAXIMA DARTING NORTHEASTWARD ACROSS
SOUTHEAST UTAH AT THE MOMENT. AT ITS PRESENT SPEED SHOULD SEE THIS
WEATHER MAKER REACHING THE FRONT RANGE URBAN CORRIDOR/DENVER
METRO AREA AROUND 00Z THIS EVENING. MODELS INDICATE GENERALLY LIGHT
QPF ON THE NORTHEAST PLAINS DURING THE EVENING HOURS AS THIS JET
MAX AND WEAK QG ASCENT PASS OVERHEAD. WRF SYNTHETIC IR CLOUD MODEL
SHOWS A FAIRLY THICK SOUTHWEST-NORTHEAST SWATH OF CLOUD COVER ACROSS
THE FORECAST AREA PRETTY MUCH ALL EVENING....AND OVER THE FAR
NORTHEAST COUNTIES THROUGH THE EARLY MORNING HOURS. THIS MATCHES UP
WELL WITH 700-500MB RH FIELDS OF THE NAM...GFS...EC AND HI RES
MODELS. CURRENT FORECAST GRIDS INDICATE SCATTERED POPS IN THE HIGH
COUNTRY...WITH THE HIGHER PRECIP CHANCES ROUGHLY SOUTH OF I-70.
ON THE PLAINS 10-20 PERCENT POPS PREVAIL...ALTHOUGH THE HRRR AND
HI RES MODEL REFLECTIVITY FIELDS INDICATE A LINE OF STORMS FORMING
IN MORGAN...EASTERN ADAMS...EASTERN ARAPAHOE AND EASTERN ELBERT
COUNTIES BETWEEN 00-03Z...THEN MOVING EAST INTO WASHINGTON AND
LINCOLN COUNTIES AS THE EVENING GOES ON. STORMS APPEAR TO FORM
ALONG A WIND SHEER AXIS IN THE AREA. SHOULD THIS HAPPEN...NO DOUBT
PRECIP CHANCES WOULD NEED TO BE REVISED UPWARD IN THIS AREA.

BY LATE TONIGHT....THE WAVE MOVES EAST OF THE STATE AS THE
SOUTHWESTERLY FLOW ALOFT TRANSITIONS MORE TO A WESTERLY COMPONENT.
THE SHIFT IN WINDS ALOFT APPEAR TO MIX DOWN MONDAY MORNING CAUSING
DRYING ALONG THE EAST FACE OF THE FRONT RANGE...PARTICULARLY UP
NEAR THE WYOMING BORDER. DURING THE DAY...COULD SEE ISOLATED
STORMS FORMING ALONG THE PALMER RIDGE AND HIGHER AREAS ACROSS
SOUTHERN PORTIONS OF THE CWFA DURING THE AFTERNOON HOURS WITH
WEAK UPSLOPE FLOW WITH NORTHERLY BOUNDARY LAYER FLOW. OTHERWISE A
DRIER DAY WITH TEMPERATURE SIMILAR OR SLIGHTLY COOLER THAN TODAY.

.LONG TERM...ON MONDAY NIGHT NIGHT...UPPER LEVEL HIGH PRESSURE IS
CENTERED OVER WEST TEXAS...WITH AN UPPER LEVEL TROUGH OF LOW
PRESSURE OVER THE NORTHERN ROCKIES. COLORADO LIES BETWEEN TWO
SYSTEMS UNDER THE INFLUENCE OF A WESTERLY FLOW ALOFT. BOTH THE NAM
AND THE GFS SHOW A 60 KT JET OVER NORTHEASTERN COLORADO...HOWEVER
ACCORDING TO THE MODELS...VERY LITTLE QG IS ASSOCIATED WITH THE
JET. AS FOR MOISTURE...MODELS SHOW THAT THE MOUNTAINS ARE VERY DRY
WITH PW`S LESS THAN ONE HALF INCH...WITH PW`S FROM THREE QUARTERS
OF AN INCH TO AN INCH EAST OF THE MOUNTAINS. NAM AND GFS SOUNDINGS
SHOW CAPE VALUES UNDER 300 J/KG...WITH DEWPOINTS IN THE 40S....AND
SOME MID LEVEL MOISTURE BETWEEN 500 AND 600 MILLIBARS. BOTH THE
NAM AND GFS ARE ALSO SHOWING LIGHT PRECIPITATION MOVING ACROSS
NORTHEASTERN COLORADO MAINLY SOUTH OF INTERSTATE 76 DURING THE
LATE EVENING AND OVERNIGHT. LOOKS LIKE THE BEST CHANCE FOR ANY
PRECIPITATION WOULD BE OVER THE PALMER DIVIDE...THEREFORE I HAVE
INCREASED POPS SLIGHTLY THERE. DUE TO THE INVERTED V SOUNDINGS...I
WOULD SUSPECT ANY STORMS WOULD BE PRODUCE MAINLY LIGHT RAIN AND
GUSTY WINDS.

ON TUESDAY INTO WEDNESDAY...DRIER AIR SPREADS ACROSS ALL OF
NORTHEASTERN COLORADO...ENDING ANY CHANCES OF PRECIPITATION ACROSS
THE CWA...WITH THE EXCEPTION OF PORTIONS OF THE CENTRAL MOUNTAINS
MAINLY SOUTH OF INTERSTATE 70.

WEDNESDAY NIGHT AND INTO THURSDAY...AN UPPER LEVEL TROUGH DROPPING
INTO THE NORTHERN ROCKIES WILL INDUCE A WEAK RIDGE OVER COLORADO.
THIS WILL PUSH TEMPERATURES ABOVE NORMAL AGAIN WITH A JUST A SLIGHT
CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON AND
EVENING HOURS.

AS THE UPPER LEVEL TROUGH MOVES EAST OVER THE NORTHERN PLAINS IT
WILL PUSH A COLD FRONT THROUGH COLORADO THURSDAY NIGHT. THIS WILL
USHER IN COOLER AIR FOR FRIDAY AND SATURDAY. NOT MUCH MOISTURE
BEHIND THE FRONT...SO WILL KEEP POPS LOW FOR NOW. IF ANY
PRECIPITATION DEVELOPS...IT IS EXPECTED TO BE LIGHT AND OCCUR
FRIDAY. SURFACE HIGH BEHIND THE FRONT WILL DRIFT SOUTH OVER COLORADO
FRIDAY. THE CLEAR SKIES COMBINED WITH THE COOL AND DRY AIRMASS WILL
LEAD TO COOL OVERNIGHT LOWS FRIDAY NIGHT.

ON SUNDAY...UPPER LEVEL RIDGE WILL BE OVER THE FOUR CORNERS. THIS
WILL SEND WARMER AIR BACK INTO COLORADO WITH HIGHS CLIMBING BACK
INTO THE 80S.
&&

.AVIATION...VFR CONDITIONS IN THE DENVER AREA THROUGH 00Z
TODAY. AFTER 00Z THIS EVENING...ISOLATED SHOWERS AND THUNDERSTORMS
MOVING OFF THE FRONT RANGE AND FORMING IN THE DENVER AREA COULD
LOWER CEILINGS TO AROUND 6000 FT AGL FOR SHORT PERIODS OF TIME.
THERE IS ALSO A SLIGHT CHANCE THAT MODERATE RAINFALL FROM PASSING
STORMS COULD BRIEFLY REDUCE VISIBILITIES TO 5 MILES. IMPROVEMENT
SHOULD OCCUR AFTER 04Z THIS EVENING WITH DRIER AIR MOVING DOWN
OFF THE FOOTHILLS. ON MONDAY...VFR CONDITIONS ARE ANTICIPATED
ALL DAY...HOWEVER THERE IS A SLIGHT CHANCE OF A LIGHT SHOWERS OR
WEAK T-STORM IN THE DENVER AREA AFTER 2 PM MDT.

.HYDROLOGY...THERE IS A CHANCE THAT THE FRONT RANGE BURN SCARS
COULD SEE A FEW SHOWERS AND THUNDERSTORMS THIS EVENING WITH
PASSAGE OF A WEAK UPPER LEVEL WEATHER DISTURBANCE. THE STRONGER
STORMS MAY PRODUCE UP TO 0.30 INCH OF RAIN IN UNDER 35 MINUTES.
WHILE FLASH FLOODING IS NOT ANTICIPATED...THE BRIEF HEAVY RAINFALL
COULD CAUSE MINOR RISES IN CREEKS AND SMALL STREAMS AS WELL AS
SOME MUDDY RUNOFF. THIS SHOWERY PRECIPITATION SHOULD COME TO AN END
BY MIDNIGHT. ON MONDAY THERE ISA A SLIGHT CHANCE OF THUNDERSTORMS
AFTER 3 PM. ANY RAINFALL SHOULD BE LIGHT...GENERALLY UNDER A TENTH
OF AN INCH.

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

SHORT TERM...BAKER
LONG TERM....KALINA/MEIER
AVIATION...BAKER

AREA FORECAST DISCUSSION

NWS DENVER CO

1105 AM MDT SUN SEP 2 2012

.UPDATE AND CORRECTION...FOR MINOR CHANGES TO FIRST AND SECOND
PERIODS AND TO CORRECT TIMES IN AVIATION DISCUSSION -
2ND PARAGRAPH

.SHORT TERM...PLAN TO MAKE FEW CHANGES TO ONGOING FORECAST AT THIS
TIME. PROBABLY THE BIGGEST CHANGE WAS TO ADJUST SKY COVERAGE TO
BETTER REFLECT THE PASSING BAND OF MID/HIGH LEVEL CLOUDS. STILL
EXPECT TO SEE THE BATCH OF CLOUDS AND PRECIP PRESENTLY NEAR THE
4-CORNERS TO RACE NORTHEAST OVER SOUTHERN AND EASTERN PORTIONS OF
THE FORECAST AREA LATER THIS AFTERNOON AND EVENING. LOW POPS STILL
ON TRACK WITH THE BETTER ODDS FOR MEASURABLE PRECIP IN MTN AREAS
ROUGHLY SOUTH OF INTERSTATE 70. CURRENT TEMPERATURE FCST LOOKS
OKAY...BUT MAY NEED TO LOWER A DEG OR TWO SHOULD CLOUDS INCREASE
EARLIER THAN EXPECTED.

.AVIATION...VFR CONDITIONS AT DENVER AREA AIRPORT THROUGH 21Z TODAY.
AFTER 21Z...ISOLATED SHOWERS AND T-STORMS FORMING OVER THE FRONT
RANGE ARE EXPECTED TO DRIFT NORTHEAST OVER PORTIONS OF THE DENVER
METRO AREA. ADDITIONAL STORM FORMATION WILL BE POSSIBLE ALONG
OUTFLOW BOUNDARIES MOVING EAST OF THE DENVER AREA AFTER 22Z. PRECIP
AMOUNTS IN THE DENVER AREA SHOULD BE ON THE LOW SIDE...GENERALLY
UNDER A TENTH OF AN INCH. SHOWERY PRECIP IN MOST INSTANCES NOT
EXPECTED TO LOWER VISIBILITIES BELOW 6 MILES. MOST OF THIS STORM
ACTIVITY IS EXPECTED TO SHIFT EAST OF THE METRO AREA AFTER 02Z WITH
GRADUAL CLEARING OVERNIGHT. LIGHT AND VARIABLE SURFACE WINDS ARE
FORECAST TO BECOME EAST-SOUTHEAST 6-12KT AFTER 19Z TODAY...THEN
GRADUALLY GOING TO A DRAINAGE PATTERN AT SPEEDS OF 5-12 KTS BY 05Z
THIS EVENING.

.HYDROLOGY...ISOLATED SHOWERS AND T-STORMS MOVING NORTHEAST AT
20-25KTS AND MAINLY OVER CENTRAL AND SOUTHERN PORTIONS OF THE FRONT
RANGE AFTER 21Z TODAY WILL THE POTENTIAL TO RAIN AMOUNTS RANGING
FROM 0.10 TO 0.30 INCH IN UNDER 40 MINUTES. DO NOT ANTICIPATE AS
MUCH WIND WITH STORMS IN THE HIGH COUNTRY TODAY. BELIEVE THE CHANCE
FOR FLASH FLOODING AT THE BURN SCARS WILL BE LOW TODAY.

.PREV DISCUSSION... /ISSUED 310 AM MDT SUN SEP 2 2012/

SHORT TERM...THE UPPER LEVEL RIDGE WILL WEAKEN TODAY WITH
INCREASING SWLY FLOW ALOFT. WATER VAPOR IMAGERY SHOWS A
DISTURBANCE OVER NWRN CO WHICH WAS TRIGGERING A FEW SHOWERS IN THE
NRN MTNS EARLY THIS MORNING. MEANWHILE A WK FNT WAS MOVING ACROSS
NERN CO THIS MORNING AND WILL BRING SLIGHTLY COOLER TEMPS WITH
READINGS ON AVERAGE 5 DEGREES COOLER THAN SAT OVER THE PLAINS. FOR
THIS AFTN SOUNDINGS HAVE BETTER INSTABILITY ACROSS NERN CO THAN
THE LAST FEW DAYS SO THERE SHOULD BE AT LEAST A SLIGHTLY BETTER
CHC FOR TSTMS ACROSS THE PLAINS INTO THE EVENING HOURS. IN THE
MTNS WILL KEEP SCT TSTMS IN THE FCST FOR THIS AFTN WITH WDLY SCT
ACTIVITY OVER THE HIGHER VALLEYS.

LONG TERM...A FLAT UPPER RIDGE WILL REMAIN SOUTH OF COLORADO MONDAY
THROUGH TUESDAY NIGHT. THE FLOW ALOFT WILL BE WEST-SOUTHWESTERLY ON
MONDAY...THEN ZONAL MONDAY NIGHT THROUGH TUESDAY NIGHT. THE
SYNOPTIC SCALE ENERGY REMAINS BENIGN THROUGH THE PERIODS. THE LOW
LEVEL PRESSURE GRADIENT IS WEAK THROUGH TUESDAY EVENING SO NORMAL
DIURNAL WIND PATTERNS WILL DOMINATE. A WEAK COLD FRONT AND UPSLOPE
IS PROGGED TO MOVE INTO THE PLAINS LATE TUESDAY NIGHT OR EARLY
WEDNESDAY. FOR MOISTURE...THERE IS SOME IN THE MID AND UPPER LEVELS
MONDAY AND MONDAY EVENING. TUESDAY AND TUESDAY NIGHT LOOK PRETTY
DRY. THE BOUNDARY LAYER DEW POINTS ARE PROGGED IN THE 30 TO MID 40S
F RANGE FOR ALL AREAS BY LATE DAY MONDAY. THEY ARE A BIT LOWER FOR
LATE DAY TUESDAY. PRECIPITABLE WATER VALUES ARE PROGGED IN THE 0.60
TO 0.90 INCH RANGE LATE DAY MONDAY...THEN IN THE 0.55 TO 0.70 INCH
RANGE LATE DAY TUESDAY. THERE IS A TAD OF CAPE OVER THE CWA LATE
DAY MONDAY...THEN ANOTHER SMALL AMOUNT IS PROGGED OVER THE
SOUTHERN CWA LATE DAY TUESDAY. THE QPF FIELDS SHOW A TAD OF
MEASURABLE RAINFALL OVER THE CWA LATE MONDAY...AND A BIT LESS LATE
DAY TUESDAY. THERE IS NOT MUCH A MID LEVEL CAP IN PLACE ON THE
LAPSE RATE FIELDS FOR LATE DAY MONDAY. THERE IS A BIT OF ONE
PROGGED FOR LATE DAY TUESDAY. FOR POPS WILL GO WITH 10-20%S BOTH
LATE DAY MONDAY AND LATE DAY TUESDAY. FOR TEMPERATURES...MONDAY`S
HIGHS ARE 0-1 C COOLER THAN TODAY`S. TUESDAY`S ARE 0-1 C WARMER
THAN MONDAY`S. FOR THE LATER DAYS...WEDNESDAY THROUGH
SATURDAY...THE UPPER RIDGE STAYS SOUTH OF COLORADO WITH ZONAL FLOW
ALOFT THROUGH THURSDAY. MODELS STILL HAVE AN UPPER TROUGH TO PUSH
ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY. THE FLOW IS MORE
NORTHWESTERLY FRIDAY AND SATURDAY. MOISTURE IS POOR ALL FOUR DAYS
FOR ALL THE CWA. A WEAK COLD FRONT IS EXPECTED EARLY ON
WEDNESDAY...THEN A SLIGHTLY STRONGER ONE COMES IN LATE THURSDAY
NIGHT/FRIDAY MORNING.

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

SHORT TERM...BAKER/RPK
LONG TERM....RJK
AVIATION...BAKER/RPK

AREA FORECAST DISCUSSION

NWS LINCOLN IL

250 PM CDT SUN SEP 2 2012

.DISCUSSION...
ISSUED 250 PM CDT SUN SEP 2 2012

THE IMPACT OF THE REMNANTS OF HURRICANE ISAAC WILL CONTINUE TO
WANE OVER THE NEXT 24 HOUR ACROSS CENTRAL AND SOUTHEAST ILLINOIS.
THEN...ATTENTION TURNS TO PERIODIC DISTURBANCES/FRONTAL PASSAGES
THAT WILL AFFECT THE REGION FROM TIME TO TIME THIS WEEK. MAIN
FORECAST PROBLEMS TODAY REVOLVE AROUND PRECIPITATION CHANCES UNTIL
ISAAC/S REMNANTS DEPART AND WITH EACH DISTURBANCE/FROPA.

12Z MODELS IN REASONABLE AGREEMENT OVER THE NEXT FEW DAYS.
HOWEVER...AGREEMENT IN THE DETAILS...ESPECIALLY WITH RESPECT TO
TIMING...WITH THE DISTURBANCES/FROPAS IS INCREASINGLY POOR TOWARD THE
END OF THE WEEK. THIS HAS BEEN A PERSISTENT PROBLEM THE PAST FEW
DAYS AND WILL CONTINUE TO FAVOR AN ENSEMBLE MEAN SOLUTION TO KNOCK
OUT SOME OF THE NOISE. AN UNFORTUNATE RESULT OF THIS METHOD IS AN
EXTENDED PERIOD OF LOW POPS.

SHORT TERM...TONIGHT THROUGH WEDNESDAY...THE UPPER CIRCULATION
CENTER OF ISAAC/S REMNANTS HAS PUSHED EAST INTO INDIANA...WITH THE
SURFACE REFLECTION LINGERING A LITTLE FURTHER TO THE WEST. THIS
HAS RESULTED IN THE BETTER RAIN/THUNDER CHANCES SHIFTING TO OUR
EAST...WITH THE SHOWERS OCCURRING LOCALLY ALMOST ENTIRELY DIURNALLY
DRIVEN. THIS SHOULD CONTINUE TO BE THE CASE THROUGH MONDAY AS THE
PRECIPITATION CHANCES GRADUALLY END FROM WEST TO EAST.

ATTENTION THEN TURNS TO A COUPLE DISTURBANCES THAT WILL PUSH A
FRONT TOWARD AND/OR THROUGH THE FORECAST AREA. THE FIRST
DISTURBANCES IS MOVING EAST ACROSS SASKATCHEWAN AND WILL PUSH A
VERY WEAK FRONT TOWARD THE REGION AND WASHES IT OUT. DO NOT REALLY
EXPECT MUCH...IF ANY...PRECIPITATION WITH THIS FEATURE BUT HAVE
MAINTAINED SLIGHT CHANCE POPS IN MOST AREAS FOR MONDAY NIGHT INTO
TUESDAY. A STRONGER FRONT WILL PUSH THROUGH WEDNESDAY...DRIVEN BY
A WAVE CURRENTLY DIGGING THROUGH BRITISH COLUMBIA. THIS FRONT HAS
A BETTER CHANCE OF PRODUCING SHOWERS/STORMS...AND IT WILL USHER IN
BELOW NORMAL TEMPERATURES FOR THE REST OF THE WEEK.

CONSIDERING HOW MUCH RAIN HAS FALLEN THE PAST COUPLE OF DAYS...FOG
WILL DEFINITELY BE A CONCERN FOR AT LEAST THE NEXT COUPLE OF
NIGHTS WHILE THE AIRMASS REMAINS VERY HUMID. HAVE LIMITED FOG
MENTION TO WESTERN SECTIONS OF THE FORECAST AREA TONIGHT DUE TO
THE LINGERING CLOUD COVER IN PLACE. FOG WILL LIKELY BE A BIGGER
THREAT MONDAY NIGHT AS THE CLOUD COVER SHOULD BE MUCH MORE MINIMAL.

LONG TERM...THURSDAY THROUGH SUNDAY...ANOTHER STRONG WAVE/FRONT
WILL PUSH THROUGH THE AREA FRIDAY OR SATURDAY AS THE MEAN UPPER
TROF FROM CENTRAL NORTH AMERICA DEEPENS AND SHIFTS EAST WITH TIME.
SPECIFIC PRECIPITATION TIMING FOR THE END OF THE WEEK IS PRETTY
UNCERTAIN. IN FACT...THE 12Z ECMWF CAME IN WITH ENOUGH COLD AIR
AND CYCLONIC FLOW BEHIND THE FRONT TO KEEP AT LEAST DIURNAL
SHOWERS A RISK THROUGH THE WEEKEND. FOR NOW...HAVE LIMITED
MENTIONABLE SHOWER/STORM CHANCES TO FRIDAY AND SATURDAY...BUT THIS
WILL CERTAINLY NEED TO BE TWEAKED AT THE ULTIMATE SOLUTION BECOMES
MORE CLEAR.

BAK
&&

.AVIATION...
ISSUED 1245 PM CDT SUN SEP 2 2012

LOW PRESSURE CONTINUES TO SPIN OVER KMTO...WITH IFR CEILINGS
ON THE NORTH/WEST SIDE OF THE SYSTEM. DUE TO ONLY VERY SLOW
EASTWARD MOVEMENT...WILL KEEP IFR CEILINGS IN PLACE THROUGH THE
AFTERNOON AT KCMI...KDEC...AND KBMI. FURTHER WEST...A DRY SLOT HAS
WORKED IN FROM THE NORTH...RESULTING IN MVFR CEILINGS AT THE
REMAINING TERMINALS. SHOWERS WILL CONTINUE TO BLOSSOM ACROSS THE
AREA THIS AFTERNOON...PARTICULARLY ALONG/EAST OF I-55. PRECIP WILL
BE LARGELY DIURNAL...WITH 12Z HRRR INDICATING SHOWERS DIMINISHING
AND COMING TO AN END BY SUNSET. QUESTION AFTER THAT BECOMES
WHETHER OR NOT ANY CLEARING CAN OCCUR AND IF FOG WILL BECOME A
PROBLEM. NAM FORECAST SOUNDINGS KEEP LOW CLOUDS IN PLACE ACROSS
CENTRAL ILLINOIS THROUGH THE NIGHT. DUE TO THE POTENTIAL FOR
PARTIAL CLEARING OVERNIGHT...WILL CONTINUE TO FORECAST PATCHY FOG
WITH VSBYS BETWEEN 2 AND 4SM. ANY FOG THAT DEVELOPS WILL
GRADUALLY LIFT INTO AN MVFR OVERCAST AFTER 14Z. SKIES WILL THEN
CLEAR OUT BY MONDAY AFTERNOON...AS LOW PRESSURE SLOWLY EXITS THE
REGION.

BARNES
&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

AREA FORECAST DISCUSSION

NWS LINCOLN IL

1245 PM CDT SUN SEP 2 2012

.DISCUSSION...
ISSUED 1040 AM CDT SUN SEP 2 2012

15Z/10AM SURFACE ANALYSIS SHOWS CENTER OF HURRICANE ISSAC REMNANTS
OVER MATTOON. DEEPEST TROPICAL MOISTURE AND STRONGEST LIFT WILL BE
LOCATED TO THE EAST/SOUTHEAST OF THE LOW ACROSS THE OHIO RIVER
VALLEY TODAY. FURTHER WEST ACROSS CENTRAL ILLINOIS...THE PRECIP
WILL BE LIGHTER AND MUCH MORE SCATTERED IN NATURE. A FEW BREAKS IN
THE OVERCAST WILL OCCUR FROM TIME TO TIME...WHICH WILL ALLOW
POCKETS OF MODERATE INSTABILITY TO DEVELOP THIS AFTERNOON. AS A
RESULT...MAY SEE ISOLATED THUNDER AS WELL. HAVE UPDATED THE FORECAST
TO LOWER POPS...OPTING TO GO WITH SCATTERED SHOWERS/ISOLATED THUNDER
ACROSS THE BOARD. DUE TO THE CLOUD COVER AND PRECIP...HIGHS WILL
ONLY REACH THE UPPER 70S AND LOWERS 80S.

.AVIATION...
ISSUED 1245 PM CDT SUN SEP 2 2012

LOW PRESSURE CONTINUES TO SPIN OVER KMTO...WITH IFR CEILINGS
ON THE NORTH/WEST SIDE OF THE SYSTEM. DUE TO ONLY VERY SLOW
EASTWARD MOVEMENT...WILL KEEP IFR CEILINGS IN PLACE THROUGH THE
AFTERNOON AT KCMI...KDEC...AND KBMI. FURTHER WEST...A DRY SLOT HAS
WORKED IN FROM THE NORTH...RESULTING IN MVFR CEILINGS AT THE
REMAINING TERMINALS. SHOWERS WILL CONTINUE TO BLOSSOM ACROSS THE
AREA THIS AFTERNOON...PARTICULARLY ALONG/EAST OF I-55. PRECIP WILL
BE LARGELY DIURNAL...WITH 12Z HRRR INDICATING SHOWERS DIMINISHING
AND COMING TO AN END BY SUNSET. QUESTION AFTER THAT BECOMES
WHETHER OR NOT ANY CLEARING CAN OCCUR AND IF FOG WILL BECOME A
PROBLEM. NAM FORECAST SOUNDINGS KEEP LOW CLOUDS IN PLACE ACROSS
CENTRAL ILLINOIS THROUGH THE NIGHT. DUE TO THE POTENTIAL FOR
PARTIAL CLEARING OVERNIGHT...WILL CONTINUE TO FORECAST PATCHY FOG
WITH VISBYS BETWEEN 2 AND 4SM. ANY FOG THAT DEVELOPS WILL
GRADUALLY LIFT INTO AN MVFR OVERCAST AFTER 14Z. SKIES WILL THEN
CLEAR OUT BY MONDAY AFTERNOON...AS LOW PRESSURE SLOWLY EXITS THE
REGION.

BARNES
&&

.PREV DISCUSSION...
ISSUED 330 AM CDT SUN SEP 2 2012

SHORT TERM...TODAY THROUGH TUESDAY NIGHT

1007 MB LOW PRESSURE (REMNANTS OF ISAAC) WAS EAST OF ST LOUIS
EARLY THIS MORNING WITH A FEW SPIRAL BANDS OF SHOWERS OVER EASTERN
AND NORTHERN COUNTIES WHILE HEAVIER SHOWERS AND ISOLATED
THUNDERSTORMS WERE INTO NE IL AND NORTHERN INDIANA. TROPICAL
AIRMASS STILL IN PLACE WITH DEWPOINTS IN THE LOWER 70S (EXCEPT 69F
AT GALESBURG). MODELS HAVE TRENDED A SLOW SE MOVEMENT OF LOW
PRESSURE FROM EAST OF ST LOUIS INTO SE IL BY EARLY EVENING AND
INTO WESTERN KY ON LABOR DAY. HAVE HIGHEST CHANCES OF SHOWERS AND
ISOLATED THUNDERSTORMS OVER EASTERN/SE IL TODAY WITH ADDITIONAL
RAINFALL AMOUNTS OF A HALF TO 1 INCH. THE RISK OF BRIEF/WEAK
TORNADOES AND HEAVIEST RAINS SHOULD SHIFT EAST OF IL OVER IN/KY
WHERE AIRMASS WILL BE MORE UNSTABLE. HIGHS GENERALLY IN THE LOWER
80S TODAY WITH A FEW UPPER 70S IN EAST CENTRAL IL WITH A FAIR AMOUNT
OF LOW CLOUD COVER...THOUGH SOME PEEKS OF SUNSHINE AS HAS BEE THE
CASE THE PAST FEW DAYS. CHANCES OF SHOWERS DIMINISH FROM WEST TO EAST
TONIGHT AND MONDAY AND COULD SEE PATCHY FOG DEVELOP OVERNIGHT
WEST/NW OF I-55 ESPECIALLY IF WE CAN CLEAR OUT DUE TO VERY MOIST
AIRMASS AND LIGHT WINDS. A BIT WARMER MONDAY WITH MORE SUNSHINE AND
HIGHS GENERALLY IN THE MID 80S.

A WEAK SHORT WAVE RACES EASTWARD INTO IL FROM THE CENTRAL PLAINS TUE
AND COULD BRING ISOLATED SHOWERS AND THUNDERSTORMS ESPECIALLY TUE
AFTERNOON WITH HUMID AIR MASS LINGERING. RISK OF SEVERE STORMS IS
WEST OF IL TUE OVER NEBRASKA WITH 5% RISK OVER SCHUYLER COUNTY IN
WEST CENTRAL IL. HIGHS IN THE MID TO UPPER 80S TUE.

LONG TERM...WEDNESDAY THROUGH SATURDAY

ENSEMBLE MODELS CONTINUE TO SHOW UPPER LEVEL TROUGHING INTO THE
MIDWEST AND GREAT LAKES REGION DURING THE 2ND HALF OF THIS WEEK
WITH A PROGRESSIVE STEERING FLOW OVER IL. A FEW DISTURBANCES TRACK
EAST SOUTHEAST INTO THE REGION BRINGING PERIODIC CHANCES OF
CONVECTION. THE BEST THREAT FOR PRECIPITATION DURING THIS PERIOD
WILL BE ON WEDNESDAY AS AN UPPER DISTURBANCE PASSES EAST ACROSS THE
UPPER GREAT LAKES AND AGAIN LATER IN THE WEEK...AS MORE ENSEMBLE
MEMBERS DROP ANOTHER DISTURBANCE INTO THE MIDWEST. COOLER AND LESS
HUMID AIR TO FILTER INTO IL AFTER WED WITH A COLD FRONT SLIDING SE
THROUGH IL WED AFTERNOON/EVENING.

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

656 PM EDT SUN SEP 2 2012

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 347 PM EDT SUN SEP 2 2012

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A STRONG SHORTWAVE/MID
LEVEL LOW MOVING NE THRU CNTRL SASKATCHEWAN. DOWNSTREAM RIDGE
EXTENDS FROM THE SW PLAINS THRU THE UPPER LAKES WHILE REMNANT OF
ISAAC DRIFTS THRU THE LWR OHIO VALLEY. DUE TO ISAAC...MOISTURE
RETURN THRU THE PLAINS HAS BEEN VERY LIMITED AS 12Z RAOBS SHOW 850MB
DWPT DEPRESSIONS BTWN 15-25C. NONETHELESS...SCT HIGH BASED
-SHRA/TSRA HAVE BEEN OCCURRING ACROSS THE DAKOTAS INTO NW MN TODAY
IN THE VCNTY OF COLD FRONT ASSOCIATED WITH THE PARENT SHORTWAVE OVER
SASKATCHEWAN. A COUPLE OF MINOR SHORTWAVES APPEAR TO BE AIDING THE
CONVECTION. IN THE SHORT TERM...MAIN FOCUS WILL BE ON PCPN CHANCES
LATE TONIGHT THRU MON AS WEAKENING COLD FRONT ARRIVES.

WITH ONLY A NARROW RIBBON OF MOISTURE SUPPORTING PCPN TO THE W...THE
EVENING HRS TONIGHT WILL REMAIN DRY WHILE AWAITING COLD
FRONT/MOISTURE RIBBON TO MOVE CLOSER. IN CONJUNCTION WITH THE COLD
FRONT...A SHORTWAVE NOW OVER THE DAKOTAS WILL LIFT NE TONIGHT. ALONG TAIL
OF WAVE AND LEFT EXIT OF SUPPORTING JET STREAK...SHOULD SEE A BAND
OF SCT CONVECTION TONIGHT. THAT CONVECTION MAY SHIFT OUT OVER LAKE
SUPERIOR AND NW UPPER MI LATE TONIGHT. AS FOR TEMPS...THE HIGHEST
MIN TEMPS TONIGHT WILL BE IN THE DOWNSLOPE AREAS NEAR LAKE
SUPERIOR...PARTICULARLY THE W WHERE MOISTENING WILL BE MORE
PRONOUNCED. TEMPS SHOULDN`T FALL LWR THAN THE MID/UPPER 60S IN THOSE
AREAS. 50S WILL BE THE RULE OVER THE SCNTRL/E.

SHORTWAVE/MID LEVEL LOW CURRENTLY OVER SASKATCHEWAN DRIFTS INTO NRN
MANITOBA MON. WITH MAIN SYSTEM WELL TO THE NW OF HERE...SFC COLD
FRONT WILL BE WEAKENING AS IT REACHES UPPER MI. LACK OF DYNAMICS AND
DIMINISHING LOW-LEVEL CONVERGENCE ALONG FRONT WILL WORK TO LIMIT
COVERAGE OF CONVECTION MON...ESPECIALLY SINCE THERE WILL BE SOME DRY
AIR TO OVERCOME. HOWEVER...NARROW RIBBON OF BOUNDARY LAYER MOISTURE
SHOULD BE SUFFICIENT FOR ISOLD/SCT CONVECTION. AS AFORMENTIONED JET
STREAK AIDING PCPN LATE TONIGHT SHIFTS NE...THE RIGHT ENTRANCE OF
THE JET WILL PROBABLY PROVIDE BEST SUPPORT FOR NEW CONVECTION IN THE
AFTN HRS OVER SCNTRL UPPER MI INTO NE WI. PROVIDED MLCAPE INCREASES
TO UPWARDS OF 1500-2000J/KG PER GFS AND ESPECIALLY NAM...DEEP LAYER
SHEAR OF 30-40KT WILL SUPPORT ORGANIZED STORMS AND SVR POTENTIAL IF
ANY STORMS DO DEVELOP. COVERAGE OF SVR STORMS WOULD LIKELY BE ISOLD.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 PM EDT SUN SEP 2 2012

LONG TERM PERIOD STARTS OUT WITH UPPER LOW OVER MANITOBA WHILE
ADDITIONAL SHORTWAVE TROUGH CURRENTLY DIGGING INTO FAR NORTHERN
BRITISH COLUMBIA MERGES WITH THE LOW ON WEDNESDAY. INITIAL FRONT
THAT MOVES THROUGH UPR MICHIGAN ON LABOR DAY LIKELY STALLS OUT
MONDAY NIGHT INTO TUESDAY AS IT PARALLELS UPPER FLOW.

MAJORITY OF SHRA/TSRA...ALBEIT ONLY ISOLD/SCT COVERAGE...SHOULD BE
DIMINISHING BY LATER MONDAY NIGHT. KEPT SMALL POPS IN ONLY FOR THE
SOUTH AND EAST CWA AS THOSE AREAS STAY IN AT LEAST A WEAK AREA OF
RIGHT ENTRANCE JET FORCING. LINGERED SLIGHT CHANCES FOR THE SAME
AREAS THROUGH MOST OF THE NIGHT AS THE SURFACE FRONT REMAINS IN THE
VICINITY AND LOW-LEVEL MOISTURE POOLS ALONG THE BOUNDARY. VERY SMALL
CHANCES BUT CAN NOT COMPLETELY PULL THE POPS JUST YET.

FRONT COULD SERVE AS FOCUS FOR MORE SHRA/TSRA ON TUESDAY AS NAM/00Z
ECMWF INDICATE H85 TROUGH AND THETA-E ADVECTION ARRIVES DURING PEAK
HEATING OF THE AFTERNOON. H85 DWPNTS ON THE LOW SIDE TO START THE
DAY...SO SHOULD SEE BETTER CHANCES OF SHRA/TSRA AFTERNOON AND
EVENING...SPREADING FROM WEST TO EAST AS H85 TROUGH CROSSES AREA.
THOUGH 0-6KM SHEAR 20-25 KTS NOT TOO IMPRESSIVE FOR ORGANIZED SEVERE
STORMS...MLCAPES AOA 1000 J/KG AND HIGH DEWPOINT DEPRESSIONS AT
H7-H5 WITH MOIST LOW-LEVELS POINT TO POSSIBLE GUSTY WINDS WITH ANY
TSRA. ANY SHRA/TSRA WOULD WANE BY LATER EVENING WITH LOSS OF
HEATING/WEAKENING SFC-H85 CONVERGENCE. GFS AND LATEST GEM-NHEM AND
12Z ECMWF FOCUS H85 TROUGH MORE LATER TUESDAY NIGHT AND MORE SO ON
WEDNESDAY WITH ARRIVAL OF PRIMARY COLD FRONT. BASED ON TREND FROM
LATEST ECMWF...DECIDED TO NOT GO TOO HIGH FOR POPS ON TUESDAY.

AS LARGER FORMED UPPER LOW COMPLEX OVER MANITOBA RUMBLES EAST INTO
ONTARIO...EXPECT SHARP COLD FRONT TO SWEEP ACROSS GREAT LAKES REGION
WEDNESDAY AND THURSDAY. WOULD THINK THERE WOULD BE DECENT CHANCE FOR
RAIN WITH THE FROPA. BY TIME FRONT ARRIVES GFS AND GEM-NHEM SHOWS
SHARP H85 WIND SHIFT AND MOISTURE ADVECTION INTO THE AREA. OTHER
MODELS ALREADY SHOVE THE H85 TROUGH THROUGH SHUNTING MORE ABUNDANT
MOISTURE SOUTHEAST OF CWA...BUT AS MENTIONED BEFORE LATEST ECMWF HAS
TRENDED THIS WAY AS WELL. CONSISTENCY ON THESE SOLUTIONS NOT THE
GREATEST. THERE ARE ALSO HINTS THAT YET ANOTHER WEAKER WAVE/H7
MOISTURE MAY BE SLIDING THROUGH AREA WHILE FRONT SLIDES THROUGH.
DETAILS CERTAINLY STILL NEED TO BE SORTED OUT AS TO LOCATION AND
COVERAGE OF BEST RAIN CHANCES ON WEDNESDAY. CHANCE POPS FOR SCT
SHRA/TSRA COVER IT FINE FOR NOW. PRESSURE GRADIENT TIGHTENS
WEDNESDAY NIGHT AND THURSDAY IN WAKE OF THE COLD FRONT BUT OTHER
THAN FOR A BRIEF PERIOD WEDNESDAY EVENING WHERE GFS SHOWS 950-925MB
WINDS 30-35 KTS...H925-H85 WINDS INTO THURSDAY ARE ONLY AROUND 20
KTS. SO EVEN THOUGH STEADY COOLING ALOFT OCCURS INTO THURSDAY...THIS
SYSTEM DOES NOT LOOK TO PRODUCE VERY STRONG WINDS AS EARLY FALL
SYSTEMS SOMETIMES CAN DO. TWO ISSUES THAT WILL NEED TO BE MONITORED
THOUGH IN WAKE OF THE COLD FROPA WILL BE AN INCREASED RISK OF RIP
CURRENTS AND POSSIBLE UPPER LOW TYPE WATERSPOUTS LATER THURSDAY INTO
FRIDAY.

ALTHOUGH HIGH PRESSURE TRIES TO BUILD IN LATE THIS WEEK IT REMAINS
PRETTY WEAK AND DIFFUSE AS UPPER FLOW IS NOT CONFLUENT. BY FAR THE
STRONGER SURFACE FEATURE WILL BE WRAPPED UP SURFACE LOW VICINITY OF
HUDSON BAY AND JAMES BAY. BY LATER THURSDAY INTO FRIDAY CANNOT RULE
OUT AT LEAST LIGHT LK EFFECT SHRA SINCE H85 TEMPS DROP TO 4-6C
/WATER TEMPS STILL RUNNING 18-20C/ AND SINCE THERE COULD BE ANOTHER
WEAKER SHORTWAVE/ADDITIONAL MOISTURE PUSHING INTO WESTERN GREAT
LAKES PER GFS/ECMWF. NOT A BIG CHANCE AS LOW-LEVEL FLOW IS NOT
THAT FAVORABLE GIVEN NEUTRAL TO ANTICYCLONIC LOOK...BUT SOME LIGHT
PRECIP SEEMS POSSIBLE.

MODEL DIFFERENCES EMERGE BY NEXT WEEKEND WITH THE MAIN ISSUE ON HOW
QUICK THE 00Z GFS BRINGS ANOTHER LARGER SCALE TROUGH EAST ACROSS THE
NORTHERN PLAINS. 00Z ECMWF INDICATES RIDGING BUILDS IN ALOFT WITH A
SHARPER SURFACE RIDGE FROM THE PLAINS INTO FAR NORTHERN PORTION OF
UPPER GREAT LAKES. 06Z-12Z RUNS OF GFS HAVE TRENDED ECMWF WAY.
LATEST COUPLE RUNS OF ECMWF POINT TO UPPER LAKES BEING ON THE DRY
FRINGE OF SET OF DISTURBANCES WHICH WOULD BRING RAIN TO PORTIONS OF
GREAT LAKES TO START NEXT WEEKEND. HPC PREFERS TO SIDE WITH ECMWF
IDEA AND THIS FORECAST WILL TILT THAT WAY AS WELL WITH A GENERAL DRY
FCST NEXT WEEKEND. AFTER SLIGHTLY THAN NORMAL HIGH TEMPERATURES
FRIDAY AND SATURDAY...EXPECT SOME MODERATION IN TEMPERATURES BY NEXT
SUNDAY.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 655 PM EDT SUN SEP 2 2012

ALTHOUGH A FEW -SHRA MAY ARRIVE AT KIWD/KCMX LATE TONIGHT AND AT
KSAW LATE MON MORNING AHEAD OF AN APPROACHING COLD FRONT...EXPECT
VFR CONDITIONS THRU THIS FCST PERIOD AS LOW-LEVEL DRY AIR HOLDS.
THERE IS A VERY SMALL POTENTIAL FOR STRATUS TO DEVELOP AT KSAW
TONIGHT AS SE WINDS COULD ADVECT MARINE MODIFIED HIGHER DWPTS OFF
LAKE MI INLAND AND UPSLOPE INTO COOLER BOUNDARY LAYER AIR. WILL BE
SOMETHING TO MONITOR. MODEST LOW-LEVEL JET AHEAD OF COLD FRONT MAY
RESULT IN LLWS AT KIWD/KCMX TONIGHT.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 347 PM EDT SUN SEP 2 2012

TIGHTENING PRES GRADIENT BTWN HIGH PRES TO THE E AND AN APPROACHING
COLD FRONT TO THE W WILL RESULT IN SE TO S WINDS INCREASING TO
AROUND 20KT TONIGHT. SOUTHERLY WINDS MAY GUST TO AROUND 25KT AT
HIGHER OBS PLATFORMS...ESPECIALLY OVER CNTRL AND ERN PORTIONS OF THE
LAKE. PRES GRADIENT THEN SLACKENS WITH PASSING/WEAKENING COLD FRONT
MON...RESULTING IN WINDS DIMINISHING BACK TO UNDER 15KT MON INTO
TUE. NEXT COLD FRONT PASSING TUE NIGHT/WED WILL BRING AN INCREASE IN
W TO NW WINDS TO AROUND 20KT...MAYBE HIGHER...LATER WED INTO THU.
WINDS WILL DIMINISH SLIGHTLY FRI AS NEXT TROF PASSES EARLY IN THE
DAY.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...VOSS
MARINE...ROLFSON

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

356 PM EDT SUN SEP 2 2012

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 347 PM EDT SUN SEP 2 2012

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 347 PM EDT SUN SEP 2 2012

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 132 PM EDT SUN SEP 2 2012

ALTHOUGH A FEW -SHRA MAY ARRIVE AT KIWD/KCMX LATE TONIGHT AHEAD OF
AN APPROACHING COLD FRONT...EXPECT VFR CONDITIONS THRU THIS FCST
PERIOD AS LOW-LEVEL DRY AIR HOLDS. THERE IS A VERY SMALL POTENTIAL
FOR STRATUS TO DEVELOP AT KSAW TONIGHT AS SE WINDS VERY SRLY ACROSS
LAKE MI...RESULTING IN ADVECTION OF MARINE MODIFIED HIGHER DWPTS
INLAND/UPSLOPE INTO COOLER BOUNDARY LAYER AIR. WILL BE SOMETHING TO
MONITOR. MODEST LOW-LEVEL JET AHEAD OF COLD FRONT MAY RESULT IN LLWS
AT KIWD/KCMX TONIGHT. WITH MUCH UNCERTAINTY ON POSSIBLE CONVECTIVE
DEVELOPMENT MON IN VCNTY OF COLD FRONT...NO MENTION OF PCPN WAS
INCLUDED AT KSAW WITH THIS FCST ISSUANCE.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 347 PM EDT SUN SEP 2 2012

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...ROLFSON

AREA FORECAST DISCUSSION

NWS MARQUETTE MI

134 PM EDT SUN SEP 2 2012

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM EDT SUN SEP 2 2012

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 429 AM EDT SUN SEP 2 2012

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 132 PM EDT SUN SEP 2 2012

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 AM EDT SUN SEP 2 2012

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC

AREA FORECAST DISCUSSION

NWS RALEIGH NC

621 PM EDT SUN SEP 2 2012

.SYNOPSIS...

WARM AND UNSETTLED WEATHER WILL CONTINUE THROUGH MID-WEEK AS THE
REMNANTS OF ISAAC APPROACH THE AREA FROM THE WEST.

.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 145 PM SUNDAY...

OVERVIEW: THE FOLLOWING SYNOPTIC FEATURES HAVE BEEN NOTED THIS
AFTERNOON...
-CIRCULATION ASSOC WITH ISAAC REMNANTS SLOWLY DRIFTING EAST ACROSS
THE MIDWEST.
-DIFFUSE SFC BOUNDARY DRAPED ACROSS NORTHCENTRAL AND NORTHEAST NC
EXTENDING TO THE EAST AND WELL OFFSHORE
-MIDLEVEL S/W RIDGE AXIS OVER THE CENTRAL CAROLINAS EXTENDING NORTH
INTO VA...WITH A VORTICITY SHEAR AXIS JUST UPSTREAM AND CROSSING THE
MOUNTAINS.

FOR THE REST OF TODAY...SCATTERED SHOWERS/TSTMS HAVE DEVELOPED
ACROSS OUR CENTRAL ZONES IN AN AREA OF LOW-LEVEL CONVERGENCE AND
MODERATE INSTABILITY. EXPECT THIS ACTIVITY TO CONTINUE THIS
AFTERNOON...AND ADDITIONAL ACTIVITY TO DEVELOP ACROSS THE THE
WESTERN PIEDMONT WITH THE APPROACHING MID-LEVEL SHEAR AXIS. OUTFLOW
BOUNDARIES FROM INITIAL ACTIVITY SHOULD TRIGGER ADDITIONAL CELLS
WHICH WILL SLOWLY MOVE TOWARD THE EAST GIVEN A 240-270 DEG STORM
MOTION <6 KTS AS SEEN IN FORECAST SOUNDINGS. LATEST MESOANALYSIS
SHOWS THE BEST INSTABILITY ACROSS THE SOUTHERN HALF OF OUR FORECAST
AREA. NOTED THAT BULK SHEAR REMAINS <20KT ACROSS OUR ENTIRE CWA. AS
FOR DCAPE...WHILE BEST VALUES FOR WIND GUSTS ARE WELL TO OUR
SOUTH...3 TO 6 HOUR RAP PROGS SUGGEST INCREASING DCAPE EXTENDING UP
ACROSS THE COASTAL PLAIN AND THE SANDHILLS AREAS. FINALLY PWAT
VALUES REMAIN RATHER HIGH (2+ INCHES) ACROSS MOST OF OUR CWA. SO IN
SUMMARY...TSTMS SHOULD BE MORE PULSE IN NATURE...AND GIVEN
ANTICIPATED SLOW MOVEMENT AND HIGH PWAT VALUES...HEAVY DOWNPOURS AND
LOCAL POOR DRAINAGE FLOODING WILL BE THE PRIMARY CONCERN TODAY. A
SECONDARY CONCERN WILL BE THE POTENTIAL FOR ISOLATED AND BRIEF
DAMAGING WIND GUSTS...PARTICULARLY ACROSS THE S/SE HALF OF OUR CWA
WHERE CAPE AND DCAPE ARE ENHANCED.

TONIGHT...SHOWER/TSTM ACTIVITY SHOULD WIND DOWN BY 10 PM LEAVING THE
OVERNIGHT PERIOD PARTLY TO MOSTLY CLOUDY. NO CHANGE IN AIRMASS FROM
RECENT DAYS...SO EXPECT LOWS IN THE LOW-MID 70S.

MONDAY AND MONDAY NIGHT...MID LEVEL CIRCULATION FROM ISAAC REMNANTS
IS FORECAST TO SLOW FORWARD MOVEMENT AND SPLIT OVER THE OH/TN VALLEY
AS IT ENCOUNTERS THE MID-LEVEL RIDGE ALONG THE MID ATLANTIC AND
CAROLINA COAST. ONE PORTION OF THE AFOREMENTIONED CIRCULATION IS
PROGGED TO MOVE TO THE NE AND ANOTHER TO THE S. SIMILAR TO TODAY...
ANOTHER VORTICITY AXIS ROTATING AROUND THE LARGE-SCALE SYSTEM IS
PROGGED TO CROSS THE MOUNTAINS DURING THE DAYTIME...AND SHOULD HELP
SERVE AS A FOCUS FOR SHOWER/TSTM DEVELOPMENT PARTICULARLY ACROSS THE
WESTERN HALF OF OUR CWA. SIMILAR TO TODAY...EXPECT A HIGH PWAT AND
LOW SHEAR ENVIRONMENT TO SUPPORT PULSE TYPE ACTIVITY AND WITH STORM
MOTION PROGGED AOB 7 KTS...ONCE AGAIN LOCALIZED POOR DRAINAGE
FLOODING LIKELY TO BE THE PRIMARY CONCERN. AS FOR POPS...WILL
CONTINUE TO CARRY STRONG-CHANCE POPS TAPERED SLIGHTLY HIGHER ACROSS
OUR WESTERN HALF. LITTLE CHANGE IN AIRMASS SO WILL CONTINUE TO SEE
ABOVE NORMAL TEMPS WITH HIGHS AROUND 90. GIVEN PROXIMITY OF ISAAC
REMNANTS AND SUBSEQUENT MID LEVEL IMPULSES AROUND IT AND ENHANCED
SOUTHERLY LOW-LEVEL FLOW... SHOWER/TSTM ACTIVITY MAY LINGER ON A BIT
LONGER INTO THE EVENING HOURS...ESP ACROSS OUR WESTERN ZONES. LOWS
MONDAY NIGHT ONCE AGAIN IN THE LOW-MID 70S.

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 210 PM SUNDAY...

FOR TUESDAY/TUESDAY NIGHT: THE QUICKLY-DAMPENING MID LEVEL SHORTWAVE
TROUGH -- THE REMAINS OF ISAAC -- WILL APPROACH WRN/CENTRAL NC FROM
THE WEST ON TUESDAY... ALTHOUGH THE BULK OF THE DPVA WILL SLIDE TO
OUR SW ACROSS GA WITH JUST A WEAK SHEAR AXIS SETTLING EASTWARD INTO
THE NC MOUNTAINS BY TUESDAY NIGHT... WHILE ANOTHER WEAK PERTURBATION
AND ATTENDANT SURFACE LOW TRACK JUST NORTH OF HIGHWAY 80 FROM LAKE
ERIE TO NEW ENGLAND. DESPITE THE WEAKENING WAVE`S APPROACH FROM THE
WEST... DYNAMIC FORCING FOR LIFT WILL BE QUITE LOW WITH WEAK MID
LEVEL RIDGING OVER CENTRAL/ERN NC... WEAK MID LEVEL WINDS... AND LOW
DEEP LAYER SHEAR (5-10 KTS AT BEST). MOISTURE WILL REMAIN DECENT IN
THE WESTERN CWA WITH PW VALUES NEAR 2.0 INCHES... BUT WILL SEE
LOWER VALUES (NEAR 1.5 INCHES--CLOSE TO NORMAL) IN THE EAST WHERE
SOME DRIER MID LEVEL AIR WILL BE PULLED ONSHORE FROM THE ESE.
ALSO... MODELS INDICATE SOMEWHAT POOR CONVECTIVE PARAMETERS WITH
1000-1500 J/KG MLCAPE CONFINED TO THE SOUTHWESTERN SECTIONS... AND
THE MODELS ARE GENERATING VERY LITTLE QPF... WITH SREF PROBABILITIES
OF ANY PRECIP HOLDING UNDER 30 PERCENT OVER ALL BUT THE FAR WEST.
WILL HOLD ONTO CHANCE POPS IN THE FAR WEST TUESDAY... BUT WILL DROP
TO JUST SLIGHT CHANCE OVER THE REST OF THE CWA. HIGHS 85-89 WITH
THICKNESSES HOLDING ABOVE NORMAL. LOWS 69-73 WITH AREAS OF FOG
DEVELOPING.

FOR WEDNESDAY/WEDNESDAY NIGHT: THE WEAK MID LEVEL SHEAR AXIS
CONTINUES TO DRIFT EASTWARD... MOVING INTO CENTRAL NC WEDNESDAY.
ACCORDINGLY... THE HIGHER PW VALUES SPREAD EASTWARD AS WELL INTO
THIS AREA... CLIMBING TO 2.0-2.2 INCHES IN A RIBBON THROUGH CENTRAL
NC. INSTABILITY MAY BE A BIT BETTER AS WELL WITH MODELS SHOWING
1200-1800 J/KG OF MLCAPE AREAWIDE... HOWEVER DEEP LAYER SHEAR
REMAINS POOR AT JUST 5-10 KTS. BUT THE HIGHER SREF PROBABILITIES OF
MEASURABLE PRECIP KICK EASTWARD WEDNESDAY WITH 50-70 PERCENT CHANCES
COVERING CENTRAL NC... AND WITH THE MINOR HEIGHT FALLS AND SLIGHT
UPTICK IN DYNAMICALLY-INDUCED LIFT... WILL STAY WITH FORECAST OF
SCATTERED STORMS AREAWIDE DEVELOPING IN THE AFTERNOON... CONTINUING
THROUGH THE EVENING. THESE WILL LIKELY BE SLOW-MOVERS... WITH A
HEIGHTENED THREAT OF STREET FLOODING. HIGHS AGAIN 85-89. LOWS 68-73
WITH ANOTHER ROUND OF FOG POSSIBLE LATE. -GIH

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 1140 AM SUNDAY...

EXPECT WET WEATHER EARLY BUT WITH DRIER CONDITIONS HEADING INTO NEXT
WEEKEND. THIS PERIOD BEGINS WITH FAST MID LEVEL FLOW AND A VERY
BROAD TROUGH COVERING THE NORTHERN THIRD OF THE CONUS INTO CANADA
(AROUND A STRONG VORTEX OVER FAR NRN ONTARIO)... WHILE AN E-W
ELONGATED RIDGE COVERS THE FAR SOUTHWEST INTO NRN MEXICO... AND A
WEAK LIKELY SUBTROPICAL LOW SITS JUST OFF THE NE COAST OF FL. A WEAK
MID LEVEL SHEAR AXIS PERSISTS THROUGH THE CENTRAL CAROLINAS... ALONG
A SURFACE LEE TROUGH... WELL AHEAD OF AN INCOMING SYNOPTIC COLD
FRONT.

FOR THURSDAY/THURSDAY NIGHT: ONE LARGE BUT LOW-AMPLITUDE SHORTWAVE
TROUGH SWINGS THROUGH THE EASTERN GREAT LAKES/ST LAWRENCE VALLEY AND
THE NORTHEAST STATES ON THURSDAY... AND THE ENSUING HEIGHT FALLS
ALOFT COMBINED WITH DEEP MOISTURE IN PLACE AND PREFRONTAL
INSTABILITY SHOULD INSTIGATE GOOD COVERAGE OF SHOWERS AND STORMS
OVER CENTRAL NC... PARTICULARLY THURSDAY AFTERNOON AND EVENING...
WITH GREATER COVERAGE ALONG/EAST OF HIGHWAY 1 GIVEN THE DRIER MID
LEVEL AIR FILTERING INTO THE WEST. LOW LEVEL THICKNESSES REMAIN 5-10
METERS ABOVE NORMAL... ALTHOUGH THIS WARMTH WILL BE SOMEWHAT
TEMPERED BY CONSIDERABLE MID AND HIGH CLOUDS. HIGHS MAINLY IN THE
MID-UPPER 80S. THE LONGWAVE TROUGH BEGINS TO DIG PROMINENTLY OVER
THE MIDWEST/PLAINS LATE THURSDAY THROUGH THURSDAY NIGHT DUE TO
ENERGY DROPPING FROM MT/WY/DAKOTAS INTO THE BROAD TROUGH BASE. IN
RESPONSE... THE DOWNSTREAM BROAD MID LEVEL TROUGHING THROUGH THE
CAROLINAS WILL WEAKEN QUICKLY AS IT HEADS TO OUR NE. (THE WEAK LOW
OFF FL APPEARS LIKELY TO STAY ENOUGH TO OUR SSE TO NOT BE A FACTOR
IN OUR WEATHER.) THE GFS/ECMWF BRING THE SURFACE COLD FRONT TO THE
WESTERN APPALACHIAN SLOPES BY LATE THURSDAY NIGHT... HOWEVER THE
PUSH OF COOL AIR IMMEDIATELY BEHIND IT WILL BE MUTED WITH THE AIR
MASS QUICKLY MODIFYING IN RESPONSE TO THE STRONG FRONTOGENESIS OVER
THE UPPER MIDWEST. SO WHILE THE MID LEVELS WILL CONTINUE TO DRY OUT
WEST TO EAST ACROSS CENTRAL NC THURSDAY NIGHT... THE REDUCTION IN
SURFACE-BASED MOISTURE WILL BE MUCH MORE SUBTLE. AS SUCH... EXPECT A
MINIMAL DIP IN TEMPS. LOWS THURSDAY NIGHT 66-71.

FOR FRIDAY/FRIDAY NIGHT: THE FRONT APPROACHING FROM THE NW EARLY
FRIDAY WILL HAVE LOST MOST OF ITS STEAM AS THE AIR MASS BEHIND IT
MODIFIES. THE LOWEST 1-2 KM WILL REMAIN MOIST ENOUGH FOR BROKEN
DIURNAL CLOUDS MUCH OF THE DAY... BUT THE MID-UPPER LEVEL DRYING AND
SUBSEQUENT LOWERING OF PW SHOULD GREATLY LIMIT COVERAGE AND STRENGTH
OF ANY CONVECTION. WITH THE ABSENCE OF MOISTURE IN THE MIXED PHASE
REGION ALOFT... LIGHTNING PRODUCTION SHOULD BE MINIMAL AND EXPECT NO
MORE THAN A FEW SHOWERS AT BEST FRIDAY WITH A LACK OF BOTH MOISTURE
AND FORCING FOR ASCENT. THICKNESSES CHANGE VERY LITTLE AND STAY
ABOVE NORMAL... SO EXPECT HIGHS OF 86-90. LOWS 65-70 WITH FAIR SKIES.

FOR SATURDAY/SUNDAY: THE CANADIAN VORTEX WOBBLES SLOWLY ACROSS JAMES
BAY WHILE THE TROUGH DIGS THROUGH THE CENTRAL US AND GREAT LAKES.
MODEL SOLUTIONS BEGIN TO DIVERGE WITH THE ECMWF SHOWING THIS
NORTHERN STREAM SEPARATING... WITH THE CANADIAN VORTEX CROSSING NRN
QUEBEC... WHILE THE TROUGH STRONGLY AMPLIFIES AND CLOSES OFF ANOTHER
LOW OVER THE OHIO VALLEY BY THE END OF THE WEEKEND. THE 06Z GFS ON
THE OTHER HAND REMAINS PHASED AND PUSHES A POSITIVELY-TILTED TROUGH
THROUGH THE NORTHEAST/APPALACHIANS/MID SOUTH... WITH A LARGE COOL
FALL HIGH PRESSURE AREA CENTERED OVER THE GREAT LAKES BUILDING
SOUTHEASTWARD INTO THE FORECAST AREA OVER THE WEEKEND. WHILE THE
ECMWF ENSEMBLE MEAN IS MUCH MORE SUBDUED WITH THE GREAT LAKES/OHIO
VALLEY TROUGHING THAN ITS OPERATIONAL COUNTERPART... THE TWO AGREE
WELL ON TIMING AND PLACEMENT... AND THIS SOLUTION HAS SUPPORT FROM
THE GEFS MEAN AND FROM THE NEW 12Z GFS. WILL LEAN TOWARD THE ECMWF
SOLUTION. EXPECT DRY WEATHER WITH TEMPS HOLDING JUST ABOVE SEASONAL
NORMALS WELL EAST OF THE TROUGH. AS THIS TROUGH MOVES EASTWARD INTO
THE MID SOUTH REGION AND APPROACHES NC... WILL BRING IN A SMALL
CHANCE OF STORMS LATE SUNDAY... ALONG WITH WARM TEMPS. -GIH

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 620 PM SUNDAY...

24 HOUR TAF PERIOD: SHOWER AND THUNDERSTORM ACTIVITY HAS MOVED OUT
OF EASTERN STATIONS BUT KINT AND KGSO ARE CURRENTLY BEING AFFECTED
BY SHOWER AND THUNDERSTORM ACTIVITY EXPECTED TO CONTINUE FOR THE
NEXT HOUR OR TWO. OVERNIGHT TONIGHT EXPECT PROBLEMS WITH FOG AND LOW
STRATUS AT ALL SITES. LOW CEILINGS 500-1000 IS THE MAIN CONCERN
OVERNIGHT WITH VISIBILITIES IN THE 3 TO 5 MILE RANGE SECONDARY.
TIMING WOULD BE AFTER 9Z UNTIL SUNRISE WITH EASTERN SITES HAVING THE
POTENTIAL TO REMAIN SUB-VFR LONGER THROUGH MID MORNING. AFTERNOON
SHOWERS AND THUNDERSTORMS WILL BE PREVALENT TOMORROW AFTERNOON WITH
THE BETTER CHANCES IN THE NORTHWEST BUT POSSIBLE AT ALL SITES. WILL
LEAVE OUT OF TAFS FOR NOW SINCE TIMING AND EXACT LOCATION IS VERY
UNCERTAIN AT THIS TIME BUT CONFIDENCE IS FAIRLY HIGH THAT THERE WILL
BE CONVECTION TOMORROW AFTERNOON INTO THE EVENING. WINDS WILL STAY
LIGHT AND VARIABLE THOUGHT THE TAF PERIOD.

LONG TERM: AS THE REMNANTS OF ISAAC APPROACH THE AREA FROM THE
WEST...SCATTERED AFTERNOON/EARLY EVENING SHOWERS AND THUNDERSTORMS
WILL BE POSSIBLE THROUGH TUESDAY. THE BIGGEST THREAT WITH THESE
STORMS WILL BE HEAVY RAIN WITH LOCALIZED POTENTIAL FOR SEVERE WIND
GUSTS. OTHERWISE CONDITIONS ARE EXPECTED TO BE LARGELY VFR THROUGH
THE LONG TERM.

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

SYNOPSIS...ELLIS
NEAR TERM....NP
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...ELLIS

AREA FORECAST DISCUSSION

NWS RALEIGH NC

210 PM EDT SUN SEP 2 2012

.SYNOPSIS...
A WARM AND HUMID AIR MASS COUPLED WITH THE SLOW APPROACH OF AN UPPER
LEVEL TROUGH WILL KEEP THE WEATHER UNSETTLED ACROSS CENTRAL NC
THROUGH MID WEEK.

.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 145 PM SUNDAY...

TONIGHT...SHOWER/TSTM ACTIVITY SHOULD WIND DOWN BY 10 PM LEAVING THE
OVERNIGHT PERIOD PARTLY TO MOSTLY CLOUDY. NO CHANGE IN AIRMASS FROM
RECENT DAYS...SO EXPECT LOWS IN THE LOW-MID 70S.

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 210 PM SUNDAY...

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 1140 AM SUNDAY...

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 145 AM SUNDAY...

24 HOUR TAF PERIOD:
SCATTERED SHOWERS AND TSTMS ACROSS THE CENTRAL PORTION OF THE STATE
ATTM WILL RESULT IN LOCALLY REDUCED CIGS AND VSBY ALONG WITH BRIEF
GUSTY SFC WINDS. THE TAF SITES MOSTLY LIKELY TO BE AFFECTED WITH IFR
CONDITIONS THROUGH 20Z INCLUDE KRDU AND KFAY. KINT/KGSO/KRWI MAY BE
IMPACTED LATER THIS AFTERNOON AS THIS ACTIVITY CONTINUES TO EVOLVE.
OUTSIDE OF THESE STORMS...EXPECT VFR CONDITIONS. LATER TONIGHT...
ENHANCED LOW LEVEL MOISTURE MAY SET THE STAGE FOR A BRIEF PERIOD OF
REDUCED VSBY AND CIGS WITH FOG AND LOW CLOUDS POSSIBLE TOWARD
SUNRISE MONDAY.

OUTLOOK: SCATTERED AFTERNOON AND EARLY EVENING SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE EACH DAY AS ENHANCED MOISTURE AND A
SLOW MOVING FRONT GRADUALLY MOVE ACROSS THE REGION. ALTHOUGH FLT
CONDITIONS ARE EXPECTED TO BE VFR MOST OF THIS TIME...ANY
SHOWER/TSTM ACTIVITY AND/OR EARLY MORNING FOG AND STRATUS WILL BE
CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS AND VSBY.

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

SYNOPSIS...WSS
NEAR TERM....NP
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...NP

AREA FORECAST DISCUSSION

NWS RALEIGH NC

145 PM EDT SUN SEP 2 2012

.SYNOPSIS...
A WARM AND HUMID AIR MASS COUPLED WITH THE SLOW APPROACH OF AN UPPER
LEVEL TROUGH WILL KEEP THE WEATHER UNSETTLED ACROSS CENTRAL NC
THROUGH MID WEEK.

.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 145 PM SUNDAY...

TONIGHT...SHOWER/TSTM ACTIVITY SHOULD WIND DOWN BY 10 PM LEAVING THE
OVERNIGHT PERIOD PARTLY TO MOSTLY CLOUDY. NO CHANGE IN AIRMASS FROM
RECENT DAYS...SO EXPECT LOWS IN THE LOW-MID 70S.

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 3 AM SUNDAY...

AN AREA OF HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST IN
CONJUNCTION WITH AN AREA OF LOW PRESSURE OVER THE LOWER OH VALLEY
WILL MAINTAIN A SLY LOW LEVEL FLOW OVER CENTRAL NC...KEEPING THE AIR
MASS QUITE MOIST. THIS MOISTURE-RICH AIR MASS COUPLED WITH A SLOW
MOVING MID-UPPER TROUGH TO OUR WEST OVER THE TN VALLEY WILL CAUSE
SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THIS PERIOD. CONVECTION
WILL BE MOST PROMINENT DURING THE HEAT OF THE DAY AND LINGER INTO
THE FIRST HALF OF THE EVENING. DUE TO ITS PROXIMITY TO BETTER
DYNAMICS/SUPPORT ALOFT...EXPECT CONVECTIVE COVERAGE TO BE GREATEST
IN THE WESTERN PIEDMONT VERSUS THE COASTAL PLAIN. DUE TO LACK OF A
DISCERNIBLE SURFACE FEATURE/BOUNDARY TO FOCUS CONVECTION...WILL KEEP
POPS IN THE SOLID CHANCE CATEGORY FOR NOW. HOWEVER...RESIDUAL
OUTFLOW BOUNDARIES FROM THE PREVIOUS DAY`S CONVECTION WILL LIKELY BE
LOCATED SOME PLACE ACROSS CENTRAL NC. THUS...ONCE ITS DETERMINED
WHERE THESE FEATURES EXISTS...POPS CAN THEN BE ACCORDINGLY INCREASED.

WHILE THERE WILL BE PLENTY OF FUEL FOR SHOWERS AND STORMS...MOST
STORMS SHOULD REMAIN BELOW SEVERE CRITERIA DUE TO LACK OF SUFFICIENT
WIND FIELD ALOFT. HOWEVER STORMS THAT ARE ABLE TO ATTAIN A DECENT
UPDRAFT FOR 20-30 MINUTES MAY PRODUCE STRONG GUSTY WINDS DUE TO
PRECIP LOADING.

MAX TEMPS TUESDAY AND WEDNESDAY WILL BE DETERMINED BY EXTENT OF
CLOUD COVERAGE IN THE MORNING AND CONVECTION IN THE AFTERNOON.
EXPECT LITTLE IF ANY CHANGES TO TEMPS THIS PERIOD FROM THE PREVIOUS
FORECAST. HIGH TEMPS IN THE MID-UPPER 80S AND MIN TEMPS NEAR
70-LOWER 70S.

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 1140 AM SUNDAY...

FOR SATURDAY/SUNDAY: THE CANADIAN VORTEX WOBBLES SLOWLY ACROSS JAMES
BAY WHILE THE TROUGH DIGS THROUGH THE CENTRAL US AND GREAT LAKES.
MODEL SOLUTIONS BEGIN TO DIVERGE WITH THE ECMWF SHOWING THIS
NORTHERN STREAM SEPARATING... WITH THE CANADIAN VORTEX CROSSING NRN
QUEBEC... WHILE THE TROUGH STRONGLY AMPLIFIES AND CLOSES OFF ANOTHER
LOW OVER THE OHIO VALLEY BY THE END OF THE WEEKEND. THE GFS ON THE
OTHER HAND REMAINS PHASED AND PUSHES A POSITIVELY-TILTED TROUGH
THROUGH THE NORTHEAST/APPALACHIANS/MID SOUTH... WITH A LARGE COOL
FALL HIGH PRESSURE AREA CENTERED OVER THE GREAT LAKES BUILDING
SOUTHEASTWARD INTO THE FORECAST AREA OVER THE WEEKEND. WHILE THE
ECMWF ENSEMBLE MEAN IS MUCH MORE SUBDUED WITH THE GREAT LAKES/OHIO
VALLEY TROUGHING THAN ITS OPERATIONAL COUNTERPART... THE TWO AGREE
WELL ON TIMING AND PLACEMENT... AND THIS SOLUTION HAS SUPPORT FROM
THE GEFS MEAN. WILL LEAN TOWARD THE ECMWF SOLUTION. EXPECT DRY
WEATHER WITH TEMPS HOLDING JUST ABOVE SEASONAL NORMALS WELL EAST OF
THE TROUGH. AS THIS TROUGH MOVES EASTWARD INTO THE MID SOUTH REGION
AND APPROACHES NC... WILL BRING IN A SMALL CHANCE OF STORMS LATE
SUNDAY... ALONG WITH WARM TEMPS. -GIH

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 145 AM SUNDAY...

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

SYNOPSIS...WSS
NEAR TERM....NP
SHORT TERM...WSS
LONG TERM...HARTFIELD
AVIATION...NP

AREA FORECAST DISCUSSION

NWS CLEVELAND OH

653 PM EDT SUN SEP 2 2012

.SYNOPSIS...
THE REMNANTS OF ISAAC WILL MOVE EAST ACROSS THE OHIO VALLEY THROUGH
TUESDAY WITH A HUMID AIRMASS AND PERIODS OF HEAVY RAIN. A WEAK FRONT
WILL HELP TO DRY US OUT ON TUESDAY NIGHT WITH A STRONGER COLD
FRONT WITH AN AIRMASS CHANGE PUSHING SOUTH ACROSS THE AREA ON
THURSDAY.

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
FEW CHANGES FOR 630 UPDATE...LEFT CHANCE POPS GOING EVERYWHERE
EXCEPT SW PORTION OF AREA.

ORIGINAL DISCUSSION...
STILL MAY GET SOME SHOWERS/THUNDERSTORMS TO DEVELOP THIS EVENING.
WHILE INSTABILITY IS NOT AS GOOD AS YESTERDAY IT SEEMS THAT CAPE
OF 2K IS ENOUGH TO GET SOME STORMS TO POP IN NORTHERN INDIANA.
WILL KEEP THE LIKELY POPS FROM FDY TO MNN TO MT VERNON FOR THIS
EVENING...WITH LESS OF A CHANCE ACROSS THE REST OF OH AND STILL
DRY ACROSS NW PA. FLASH FLOOD GUIDANCE IS LOW /AROUND ONE INCH IN
THREE HOURS/ FROM THE RAIN LAST NIGHT ACROSS THE FAR SOUTHWEST.
ANY THUNDERSTORMS THAT DO DEVELOP THIS EVENING WILL HAVE THE
POTENTIAL FOR HEAVY RAIN BUT WE HAVE HAD ALL DAY RAIN FREE THERE
TO ALLOW THE WATER TO RECEDE. WIDESPREAD FLOODING TO PROMPT A
FLASH FLOOD/FLOOD WARNING IS NOT EXPECTED. ISOLATED MINOR
FLOODING COULD OCCUR. THE REMAINDER OF THE NIGHT LOOKS DRIER THAN
NOT AND JUST LINGER LOW PRECIP CHANCES THROUGH THE NIGHT. DID NOT
MENTION THUNDER OVERNIGHT EITHER BASED MORE ON SREF PROB. MORE
HUMID AIR IS STARTING TO CREEP INTO NW PA WITH MID 60S DEWPOINTS
AT GKJ/MEADVILLE. SO WHILE ERI MAY STILL HAVE A RELATIVELY
COMFORTABLE NIGHT...THE REST OF NRN OH WILL BE WARM AND HUMID
TONIGHT. LOWS WILL BE SIMILAR TO LAST NIGHT. WE WILL KEEP THE
OVERCAST SKIES.

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
LOW SPINNING ACROSS ILLINOIS WILL CONTINUE TO FILL AND DRIFT EAST-
SOUTHEAST OVER THE NEXT TWO DAYS. COVERAGE OF SHOWERS/TS COULD BE
ON THE UPTICK FOR MONDAY. HAVE MAINTAINED SOME OF THE LIKELY POPS
ESPECIALLY ACROSS THE SOUTH AND SOUTHEAST. STUCK WITH SIMILAR
HIGHS FOR TOMORROW. UPPER TROUGH BEGINS TO OPEN UP AND WITH SOME
DIURNAL HEATING TS SHOULD POP UP. WILL HAVE TO CONTINUE THE PRECIP
CHANCES INTO MONDAY NIGHT. AT THIS POINT WE WILL BE GETTING SOME
EXTRA UPPER SUPPORT IN THE FORM OF A SHORTWAVE/JET COMING ACROSS
THE GREAT LAKES. THE COLD FRONT WILL MOVE ACROSS TUESDAY. WE WILL
STILL HAVE TO BE ON THE LOOKOUT FOR HEAVIER RAINFALL ESPECIALLY
LATER MONDAY NIGHT AND TUESDAY WITH BETTER FOCUSING MECHANISMS
LOCALLY. LOCALIZED FLOODING WILL STILL BE A CONCERN THROUGH
TUESDAY.

WEDNESDAY LOOKS LIKE THE FIRST GOOD DRY/IN BETWEEN SYSTEMS DAY.
WEAK HIGH PRESSURE OVER THE AREA AND SOME SUN SHOULD BE ABLE TO
BRING TEMPS UP INTO THE MID 80S...OR MAYBE EVEN SOME UPPER 80S. WE
WILL NOT GET A GOOD AIRMASS CHANGE UNTIL AFTER WEDNESDAY NIGHT
WITH THE NEXT SYSTEM IN THE EXTENDED.

.LONG TERM /THURSDAY THROUGH SUNDAY/...
A COLD FRONT WILL MOVE ACROSS THE REGION THURSDAY WITH SOME
SCATTERED SHOWERS AND THUNDERSTORMS ANTICIPATED. THE FRONT SHOULD
CLEAR THE ENTIRE REGION BY THURSDAY EVENING. THIS WILL ALLOW HIGH
PRESSURE TO RETURN FOR FRIDAY. THIS LOOKS TO BE SHORT LIVED AS THE
NEXT TROUGH MOVES INTO THE WESTERN GREAT LAKES ON FRIDAY.

TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE SEASONAL AVERAGES ON
THURSDAY. COOLER IN THE WAKE OF THE FRONT FOR FRIDAY INTO SATURDAY
WITH HIGHS GENERALLY IN THE MIDDLE TO UPPER 70S.

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
SATELLITE LOOP SHOWS THE CENTER OF THE REMNANTS OF ISAAC OVER SERN
IL AT 23Z WITH RADAR SHOWING CONVECTION FROM CENTRAL INDIANA
THROUGH THE KDAY VICINITY INTO SERN OHIO. MORE CONVECTION IS
MOVING NORTH OUT OF KY. ACROSS NWRN OHIO AND NWRN PA CONDITIONS
RANGE FROM MOSTLY VFR FAR EAST TO VFR/MVFR WEST AND SOUTH.
DEWPOINTS 65 TO 70 ACROSS MUCH OF THE AREA WITH LOWER 70S IN KFDY
AND UPPER 50S KERI. FOLLOWING THE HRRR HIGH RESOLUTION MODEL HAVE
KEPT PRECIP OUT OF THE AREA OVERNIGHT. BEST CHANCES HOWEVER WOULD
BE FROM KFDY TO KMFD IF THE BAND DID MANAGE TO REACH THE AREA.
MAIN CONCERN OF THE OVERNIGHT WOULD BE LOWERING CIGS AND
VISIBILITIES IN FOG AND STRATUS WITH DEEP MOISTURE ACROSS THE
AREA. DID BRING TAFS DOWN THROUGH MVFR AFTER MIDNIGHT TO MVFR/IFR
AROUND SUNRISE. AT KERI...WINDS EXPECTED TO TURN SE OVERNIGHT
WHICH WOULD BRING MORE MOISTURE INTO THE AREA SO DID BRING MVFR
CONDITIONS THERE OVERNIGHT AS WELL. ON MONDAY MODELS SHOW
CIRCULATION MOVING SE IN KY. BEST CHANCE FOR CONVECTION GETTING
INTO THE AREA WOULD BE THE SOUTH CENTRAL COUNTIES OF THE CWA. FOR
NOW BROUGHT VCTS TO THE AREA AT KMFD AND KCAK FOR THE AFTERNOON.

.OUTLOOK...NON VFR POSSIBLE MONDAY NIGHT AND TUESDAY WITH
OVERNIGHT AND EARLY MORNING FOG AS WELL AS SCATTERED TO NUMEROUS
SHOWERS/THUNDERSTORMS.

.MARINE...
WINDS HAVE INCREASED TO AROUND 15 KNOTS FOR THE OPEN WATERS AND A
PORTION OF THE NEARSHORE WATERS FROM CONNEAUT TO RIPLEY. THIS HAS
CAUSED SOME LOCALLY HIGHER WAVES FOR THE ERIE AREA WITH 2 TO 4 FOOT
WAVES A DECENT BET INTO THE EVENING. WINDS SHOULD DECREASE THIS
EVENING WITH WAVES DECREASING.

OTHERWISE WE CONTINUE TO WATCH LOW PRESSURE THAT WILL TRACK ALONG
THE OHIO RIVER VALLEY INTO MONDAY NIGHT. THIS WILL KEEP AN EASTERLY
FLOW ON THE LAKE UNTIL A WEAKENING COLD FRONT PASSES ON TUESDAY.
WINDS WILL SHIFT AROUND TO THE NW AND NORTH WITH THE FRONTAL
PASSAGE. WINDS AT THIS POINT DO NOT LOOK STRONG ENOUGH TO NEED A
SMALL CRAFT ADVISORY.

HIGH PRESSURE WILL TAKE CONTROL OF LAKE ERIE TUESDAY NIGHT INTO
WEDNESDAY. A STRONGER COLD FRONT LOOKS TO ARRIVE ON THURSDAY WITH
SOME GUSTY NW WINDS POSSIBLE. THE STRONGER WINDS MAY NOT ARRIVE
UNTIL THURSDAY NIGHT AS HIGH PRESSURE BUILDS ONTO THE WESTERN END OF
THE LAKE.

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.

$$
SYNOPSIS...DJB/OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...MULLEN
AVIATION...TK
MARINE...MULLEN

AREA FORECAST DISCUSSION

NWS MORRISTOWN TN

239 PM EDT SUN SEP 2 2012

.SHORT TERM (TONIGHT AND MONDAY)...
THE SLOW EASTWARD MOVEMENT OF THE REMNANT LOW FROM ISSAC AND A VERY
MOIST AIRMASS IN PLACE WITH PW VALUES ABOVE 2 INCHES WILL MAKE FOR A
WET SHORT TERM PERIOD. AFTER A ROUND OF SHOWERS AND THUNDERSTORMS
PASSES THROUGH THE AREA THIS AFTERNOON...ANOTHER ROUND IS SHOWN BY
THE NAM AND THE RUC ARRIVING TOWARD MIDNIGHT. STRONG TO SEVERE
STORMS ARE EXPECTED TO DEVELOP ACROSS NORTHERN MS/AL IN A LOW LEVEL
CONVERGENCE ZONE AND THETA-E MAX...AND MOVE NORTHEAST INTO OUR AREA.
WHILE THE STORMS SHOULD LOSE SOME INTENSITY DUE TO DIMINISHING
SURFACE-BASED INSTABILITY...SOME ELEVATED INSTABILITY AND A 30-40
KT LLJ WILL HELP KEEP A CHANCE OF STRONG STORMS IN THE SOUTHERN
CUMBERLAND PLATEAU AND SOUTHERN TN VALLEY TONIGHT. GUSTY WINDS AND
HEAVY RAIN WILL BE THE MAIN THREATS. CATEGORICAL POPS WILL CONTINUE
FROM TONIGHT THROUGH THE DAY MONDAY AS THE CLOSED CYCLONIC
CIRCULATION MOVES DIRECTLY OVER THE AREA. WHILE THE BEST DYNAMICS
FOR LIFT WILL BE TO OUR EAST...COOLING MIDLEVEL TEMPS UNDER THE LOW
AND A TROPICAL AIR MASS WILL KEEP PERIODS OF SHOWERS AND
THUNDERSTORMS GOING THROUGH THE DAY.

.LONG TERM (MONDAY NIGHT THROUGH SUNDAY)...
WEAKENING LOW PRESSURE SYSTEM SLIDES SOUTHEAST AND LOSES IDENTITY
OVER THE EAST TN VALLEY EARLY IN THE PERIOD. LAYER MOISTURE REMAINS
HIGH WITH ABOVE NORMAL PRECIPITATION CHANCES AND TEMPERATURES
THROUGH WEDNESDAY. DEEPER MOISTURE SHIFTS EAST FOR THE LATER HALF OF
THE WEAK WITH DIURNAL CONVECTION FAVORING THE HIGHER ELEVATIONS.
MODELS CONTINUE TREND OF DEVELOPING STRONG TROUGH OVER THE EASTERN
U.S. BY LATE IN THE PERIOD. SIGNIFICANT COLD FRONT PROGGED TO MOVE
INTO THE SOUTHERN APPALACHIANS LATE SAT OR EARLY SUN. STRONG
CONVECTION A POSSIBILITY SAT AHEAD OF FRONT. TROUGH AXIS REMAINS
WEST OF AREA SUNDAY WITH LINGERING PRECIPITATION CHANCES. DRY
CONDITIONS AND COOL NIGHTS SETTING UP FOR EARLY NEXT WEEK.

.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 72 85 72 86 71 / 90 90 50 60 30
KNOXVILLE MCGHEE TYSON AIRPORT, TN 72 83 70 85 70 / 90 90 50 60 30
OAK RIDGE, TN 71 82 71 85 69 / 90 90 50 60 30
TRI CITIES AIRPORT, TN 70 83 70 84 68 / 70 90 50 60 40

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.

DGS/SON

AREA FORECAST DISCUSSION

NWS LA CROSSE WI

239 PM CDT SUN SEP 2 2012

.SHORT TERM...TONIGHT THROUGH WEDNESDAY
239 PM CDT SUN SEP 2 2012

MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THROUGHOUT AND
ANY SEVERE WEATHER POTENTIAL FOR MONDAY/LABOR DAY.

CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A DEEP UPPER LOW OVER SASKATCHEWAN....RIDGING OVER THE
WESTERN GREAT LAKES REGION...AND THE REMNANTS OF ISAAC IN SOUTHWEST
INDIANA. WITHIN THE SOUTHWEST FLOW BETWEEN THE UPPER LOW AND THE
RIDGING...A SHORTWAVE WAS PRESENT FROM LAKE WINNIPEG TO CENTRAL
SOUTH DAKOTA. THE COMBINATION OF DPVA AHEAD OF THIS SHORTWAVE AND
LOW TO MID LEVEL MOISTURE TRANSPORT SURGING NORTH HAS KEPT SOME
SHOWERS AND THUNDERSTORMS GOING OVER NORTHWEST MINNESOTA. THIS
MOISTURE TRANSPORT CAN BE SEEN IN SOME OF THE GOES DERIVED
PRECIPITABLE WATER IMAGERY...WHERE VALUES ARE IN THE 1-1.3 INCH
RANGE FROM EASTERN NEBRASKA INTO WESTERN MINNESOTA. ASSOCIATED WITH
THIS SHORTWAVE AT THE SURFACE IS A COLD FRONT THAT STRETCHES FROM
NORTH CENTRAL MINNESOTA BACK INTO SOUTHEAST SOUTH DAKOTA. OVER OUR
AREA...PLENTY OF SUNSHINE CONTINUES...THANKS TO DRY AIR PRESENT AS
SEEN ON THE 12Z MPX SOUNDING. MIXING FROM THE SUN COMBINED WITH
850MB TEMPS AROUND 18C PER 12Z SOUNDINGS ALLOWING TEMPERATURES TO
CLIMB INTO THE LOW TO MID 80S. SOME CUMULUS HAS FORMED OVER THE
SOUTHEAST HALF OF THE AREA...THOUGH...REFLECTIVE OF ISAAC MOISTURE
BEGINNING TO GET PULLED NORTHWEST AHEAD OF THE SHORTWAVE/FRONT. THAT
MOISTURE CAN BE SEEN TOO ON GOES PRECIPITABLE WATER IMAGERY.

TONIGHT AND MONDAY...THE SHORTWAVE SEEN OVER THE DAKOTAS IS PROGGED
TO PUSH EAST-NORTHEAST IN RESPONSE TO THE DEEP UPPER LOW IN CANADA
HEADING EAST. AS THE SHORTWAVE HEADS INTO THE RIDGE OVER THE
FORECAST AREA...IT LOOKS LIKE IT WILL WEAKEN...BUT COME THROUGH
NORTHERN SECTIONS OF THE FORECAST AREA AT A GOOD TIME FOR CONVECTIVE
INITIATION...I.E. MONDAY AFTERNOON. WITH THE SHORTWAVE WEAKENING...
SO DOES THE FRONT ASSOCIATED WITH IT. HOWEVER...ALSO OF INTEREST IS
MOST MODELS SHOWING A SHORTWAVE COMING OUT OF UTAH/COLORADO RIGHT
NOW. THIS SHORTWAVE GETS PICKED UP BY THE SOUTHWEST FLOW AND ENTERS
THE SOUTHERN PORTION OF THE FORECAST AREA DURING THE AFTERNOON. SO
ALTHOUGH THE SURFACE FRONTAL FEATURE IS WEAKENING...THERE ARE A
COUPLE OF AIDES ALOFT FOR CONVECTION. BEFORE DISCUSSING MONDAY
FURTHER...BACK TO TONIGHT. ANTICIPATING CONVECTIVE DEVELOPMENT ALONG
THE FRONT LATE THIS AFTERNOON OR DURING THE EVENING IN WESTERN
MINNESOTA. THIS ACTIVITY SHOULD WEAKEN OVERNIGHT WITH LOSS OF
HEATING...BUT SOME COULD LINGER AND SCRAPE THE NORTHWEST SECTION OF
THE FORECAST AREA VERY LATE IN THE NIGHT. CERTAINLY THE MOISTURE
TRANSPORT THROUGHOUT THE 925-700MB LAYER STAYING FOCUSED UP WELL TO
THE NORTH DOESNT HELP TO MAINTAIN CONVECTION. IT IS ENTIRELY
POSSIBLE MONDAY MORNING THAT NO PRECIPITATION IS AROUND...A BREAK
BETWEEN THE TONIGHT ACTIVITY DIMINISHING AND AFTERNOON ACTIVITY
STARTING UP. FOR THE AFTERNOON...BUILDING INSTABILITY WITH MLCAPES
OF 1000-2000 J/KG COMBINED WITH THE TWO SHORTWAVES SHOULD INITIATE
CONVECTION. IN FACT...THE ONE SHORTWAVE COMING FROM THE SOUTHWEST
MAY END UP HAVING MOST OF THE CONVECTION...AS NOTED BY THE 02.12Z
SPCWRF-NMM...HIRESW-ARW AND NAM. AS SUCH...HAVE INCREASED
PRECIPITATION CHANCES TO 50 PERCENT SOUTH OF I-90. REGARDING SEVERE
RISK...ONLY AREA OF CONCERN IS AHEAD OF THAT SHORTWAVE...WHERE
LOCALIZED 0-6KM SHEAR VALUES JUMP UP TO 25-30KT. OUTSIDE OF
THAT...0-3KM AND 0-6KM SHEAR VALUES ARE GENERALLY BELOW 20 KTS.
THEREFORE...THINKING MOST CONVECTION NORTH OF I-90 SHOULD STAY
SUB-SEVERE WHILE THERE COULD BE A RISK SOUTH OF I-90. FOR
TEMPERATURES...INCREASING SOUTHERLY FLOW AND CLOUDS WILL RESULT IN A
WARMER NIGHT TONIGHT. SOME CLOUDS AROUND ON MONDAY MAKE HIGHS A
LITTLE DIFFICULT...BUT WITH 850MB TEMPS STILL NEAR 18C AND SOME
SUN...HIGHS SHOULD AT LEAST GET BACK UP INTO THE LOW TO EVEN MID 80S.

MONDAY NIGHT AND TUESDAY...A WEST-SOUTHWEST 500MB FLOW CONTINUES...
AHEAD OF WHAT IS FORECAST TO BE A POTENT SHORTWAVE DROPPING DOWN
INTO SOUTH CENTRAL CANADA AND THE NORTHWEST DAKOTAS BY 00Z
WEDNESDAY. THERE ARE NO REAL DISCERNIBLE SHORTWAVES COMING
THROUGH THE FLOW AND IMPACTING THE FORECAST AREA ACCORDING TO THE
MODELS. LOOKING AT MOISTURE TRANSPORT AND ISENTROPIC LIFT
FIELDS...THERE IS NOTHING REALLY TO NOTE EITHER THAT SUGGEST
PRECIPITATION...AT LEAST FROM THE 02.12Z NAM/GFS. THEREFORE...ONCE
WHATEVER CONVECTION OCCURS MONDAY AFTERNOON PUSHES OFF TO THE
EAST...LIKELY EARLY IN THE EVENING...DRY CONDITIONS COULD OCCUR
RIGHT THROUGH TUESDAY. THIS IS A DEFINITE CHANGE FROM PREVIOUS
MODEL RUNS...EVEN THE 02.00Z ECMWF...WHICH HAD SOME BETTER
MOISTURE TRANSPORT AHEAD OF THAT POTENT SHORTWAVE COMING DOWN TO
INITIATE CONVECTION. FOR NOW WILL LOWER PRECIPITATION CHANCES INTO
THE 15-25 PERCENT RANGE...BUT FUTURE FORECASTS MAY BE ABLE TO PULL
THESE CHANCES ENTIRELY IF TRENDS CONTINUE. ANOTHER ITEM TO WATCH
IS FOG TUESDAY MORNING. IF SKIES CAN CLEAR OUT...DECOUPLING OF
WINDS AND ANY RAIN FROM MONDAY WOULD LEAD TO FOG DEVELOPMENT. DUE
TO UNCERTAINTY ON CLOUDS...HAVE LEFT OUT FOG. DESPITE THE
SHORTWAVE PASSAGE MONDAY EVENING...850MB TEMPS STAY WARM IN THE
18-20C RANGE THROUGH TUESDAY. IN ADDITION... DEWPOINTS DO NOT LOOK
TO DROP MUCH IF AT ALL. THEREFORE... ANTICIPATING SIMILAR LOW AND
HIGH TEMPERATURES TO TONIGHT AND MONDAY.

TUESDAY NIGHT AND WEDNESDAY...THAT POTENT SHORTWAVE TROUGH COMING
INTO THE NORTHWEST DAKOTAS LATE TUESDAY IS WELL AGREED UPON BY
MODELS TO MOVE OVER MINNESOTA BY 12Z WEDNESDAY...THEN CONTINUE ITS
FAST MOTION EAST AND REACH WESTERN LOWER MICHIGAN BY 00Z THURSDAY.
PRETTY STRONG FORCING THIS TROUGH...NOTED IN 500-300MB PV
FIELDS...THOUGH MOST OF IT STAYS NORTH OF THE FORECAST AREA. THERE
IS SOME MOISTURE TRANSPORT AND ISENTROPIC LIFT ACCOMPANYING THE
TROUGH...SO WITH THE WEAK HEIGHT FALLS IN OUR AREA WE SHOULD SEE
SOME PRECIPITATION MOVE THROUGH. MOST LIKELY TIME PERIOD APPEARS TO
OCCUR BETWEEN 06Z-18Z WEDNESDAY. PREVIOUS FORECAST PRECIPITATION
CHANCES REFLECT THIS WELL. STRONG ISENTROPIC DESCENT AND SUBSIDENCE
BEHIND THE TROUGH WILL ALLOW FOR DRYING AND CLEARING CONDITIONS
AFTER 18Z WEDNESDAY. THEREFORE...HAVE DRIED OUT THE FORECAST AREA
FOR THE AFTERNOON. NOTE...IT COULD ALSO BE PRETTY BREEZY IN THE
AFTERNOON AS PRESSURE GRADIENT BRIEFLY TIGHTENS...DEEP MIXING AND
COLD ADVECTION OCCUR. REGARDING TEMPERATURES...850MB TEMPS HOLD
BETWEEN 18-20C TUESDAY NIGHT...BUT ONCE THE FRONT MOVES THROUGH WITH
THE SHORTWAVE WEDNESDAY MORNING...THESE TEMPS FALL TO 10-12C BY 00Z
THURSDAY. STILL...HIGHS ON WEDNESDAY SHOULD BE ABLE TO TOP OUT IN
THE MID 70S TO LOW 80S WITH THE SUN IN THE AFTERNOON. WARM NIGHT
LIKELY TUESDAY NIGHT AHEAD OF THE FRONT AND RELATIVELY HIGH
DEWPOINTS.

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
239 PM CDT SUN SEP 2 2012

SURPRISINGLY...THE 02.12Z ECMWF/GFS/CANADIAN AND GFS ENSEMBLES ARE
ALL IN REALLY GOOD AGREEMENT WITH THE UPPER AIR AND SURFACE PATTERNS
THROUGH SATURDAY. SOME DIFFERENCES START TO SHOW UP ON SUNDAY...BUT
GIVEN THE AMPLIFICATION FORECAST TO OCCUR...IT IS SURPRISING TO SEE
THE GOOD AGREEMENT. THE LONG TERM PERIOD STARTS OFF WITH UPPER
TROUGHING OVER MUCH OF CENTRAL CANADA WITH A POTENT SHORTWAVE
DROPPING DOWN THROUGH ALBERTA. THIS SHORTWAVE ENDS UP CARVING OUT A
FAIRLY DEEP TROUGH AS IT DIGS SOUTHEAST...REACHING THE OHIO VALLEY
SATURDAY MORNING. AS THIS SHORTWAVE DIGS...A FRONTOGENESIS ZONE
LOOKS TO FORM ACROSS THE FORECAST AREA. THIS APPEARS TO OCCUR
THURSDAY NIGHT AND LASTS THROUGH FRIDAY NIGHT. OVERALL...THE BEST
MOISTURE AND FRONTOGENESIS FORCING STAYS SOUTH...THEREFORE
PRECIPITATION CHANCES ARE ONLY IN THE 20-30 RANGE. ON SATURDAY...
BOTH THE 02.00Z AND 02.12Z ECMWF END UP DEVELOPING A RELATIVELY
STRONG SURFACE LOW IN INDIANA...PARTIALLY CAUSED BY THE UPPER TROUGH
BEGINNING TO CLOSE OFF. THE 02.00Z ECMWF HAD DEFORMATION SHOWERS
INTO THE SOUTHEASTERN HALF OF THE FORECAST AREA FOR SATURDAY.
HOWEVER...THE NEW 02.12Z ECMWF HAS SHOVED THEM OFF TO THE EAST. FOR
NOW...JUST PLACED A 20 PERCENT CHANCE IN THE AREA AROUND GRANT
COUNTY. THE GFS AND CANADIAN ARE MOSTLY DRY. THE REST OF THE WEEKEND
AND GOING INTO EARLY NEXT WEEK WILL ALL HINGE ON WHAT HAPPENS WITH
THE UPPER TROUGH/LOW. THE NEW 02.12Z ECMWF KEEPS IT OVER
INDIANA...LIKE SOME OF THE 02.12Z GFS ENSEMBLES. THE 02.12Z GFS HAS
IT MORE PROGRESSIVE. EITHER SOLUTION LOOKS DRY FOR THE FORECAST
AREA...BUT CLOUDS AND TEMPERATURES WOULD BE GREATLY AFFECTED...WITH
THE FARTHER WEST SOLUTION HOLDING MORE CLOUDS AND COOLER AIR IN THE
FORECAST AREA. SOME OF THE MOVEMENT OF THE UPPER TROUGH/LOW WILL
DEPEND ON TROPICAL STORM LESLIE WHICH IS FORECAST TO MOVE THROUGH
THE WESTERN ATLANTIC AND STRENGTHEN...LIKELY BLOCKING UP THE FLOW.

REGARDING TEMPERATURES...THEY WILL BE ON THE COOL DOWN AS THE UPPER
TROUGH FORMS. 850MB TEMPS FALL FROM THE 10-12C ON THURSDAY TO 6-8C
ON SATURDAY. AS SUCH...HIGHS ARE ONLY FORECAST TO PERHAPS REACH 70
ON SATURDAY. SATURDAY NIGHT COULD BE QUITE COOL...DEPENDING ON
CLOUDS...WITH HIGH PRESSURE POSSIBLY MOVING IN AT THE SURFACE FROM
THE NORTHWEST. SOME SLIGHT REBOUND IN TEMPERATURES ARE ANTICIPATED
ON SUNDAY.

.AVIATION...THIS AFTERNOON THROUGH MONDAY
1205 PM CDT SUN SEP 2 2012

MODEL SOUNDINGS SHOWING DIURNAL WARMING PRODUCING MIXING TO NEAR
850MB THIS AFTERNOON. WITH AN INCREASE OF LOWER LEVEL MOISTURE ON
SOUTHEAST LOW LEVEL FLOW...A FEW VFR CUMULUS EXPECTED THIS AFTERNOON
NEAR THE TOP OF THE MIXING...DISSIPATING LATE THIS AFTERNOON/EARLY
THIS EVENING. APPROACHING TROUGH/COLD FRONT FROM THE NORTHERN PLAINS
EXPECTED TO TRIGGER SCT SHRA/TSRA LATE THIS AFTERNOON/EVENING.
MID/HIGH LEVEL DEBRIS CLOUDS FROM THIS CONVECTION TO THEN SPREAD
ACROSS THE TAF SITES LATER THIS EVENING/OVERNIGHT INTO MON MORNING.
MODELS INDICATING IFR FOG POTENTIAL AT BOTH KRST/KLSE TONIGHT. WITH
THE BKN-OVC HIGHER LEVEL DEBRIS CLOUDS EXPECTED LATER TONIGHT ALONG
WITH SOUTH TO SOUTHEAST GRADIENT WINDS IN THE 5-10KT RANGE...TONIGHT
IS NOT SHAPING UP TO BE AN OVERLY FAVORABLE RADIATIONAL IFR FOG
NIGHT. DID INCLUDE SOME 5SM BR AT BOTH KRST/KLSE IN THE 09-13Z
TIME-FRAME TO ACCOUNT FOR THE MORE MOIST AIRMASS MOVING INTO THE
AREA AHEAD OF THE TROUGH/FRONT. APPEARS CONVECTION IN THE FCST AREA
WITH THE FRONT WILL MAINLY OCCUR AFTER 18Z MON. LATER TAF CYCLES
WILL HAVE TO CONSIDER SHRA/TSRA CHANCES FOR MON AFTERNOON AND ANY
NEED FOR VCSH/SHRA/TSRA/CB MENTIONS IN KRST/KLSE TAFS. AT THIS TIME
IT APPEARS CONVECTION MON AFTERNOON WOULD BE SCT AND TAFS MAY ONLY
NEED VCSH/VCTS FOR A PORTION OF THE 18-00Z MON TIME-FRAME AS THE
FRONT/LINE OF SCT CONVECTION PASSES.

.ARX WATCHES/WARNINGS/ADVISORIES...
239 PM CDT SUN SEP 2 2012

WI...NONE.
MN...NONE.
IA...NONE.

SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RRS