Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/24/13

AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 750 PM MST FRI AUG 23 2013

...UPDATED AVIATION...MAIN DISCUSSION...AND WWA AREAS...

.SYNOPSIS...
A LONG DURATION RAIN EVENT IS ANTICIPATED THIS WEEKEND ACROSS THE
REGION WITH BELOW NORMAL TEMPERATURES. HEAVY RAIN AND LOCALIZED
FLOODING MAY OCCUR...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA. PRECIPITATION CHANCES DECREASE BY EARLY NEXT
WEEK...AND INCREASED MOISTURE WILL CONTINUE THROUGH THE REMAINDER OF
THE WEEK...ALONG WITH NEAR NORMAL TEMPERATURES.

&&

.DISCUSSION...
ORGANIZED THUNDERSTORM ACTIVITY HAS BEEN STRUGGLING THROUGH THE
EARLY EVENING HOURS DUE TO MORE CONFLUENT FLOW ALOFT AND SOMEWHAT
UNSUPPORTIVE VERTICAL MOTION. 00Z SOUNDINGS ALSO INDICATE A DISTINCT
SHIFT IN MOISTURE PROFILES...WITH KPSR BOUNDARY LAYER MIXING RATIOS
FALLING CLOSER TO 8 G/KG...WHILE KTWC HAS MAINTAINED WELL MIXED
MOISTURE CLOSER TO 10 G/KG. MODEL FORECAST GUIDANCE HAS BEEN OF
LITTLE HELP WITH WIDELY VARYING SOLUTIONS...AND EVEN THE RECENTLY
MORE RELIABLE HRRR HAS OSCILLATED ON REFLECTIVITY TIMING AND
COVERAGE ACROSS THE REGION FROM EACH HOURLY INITIALIZATION. IF
ANYTHING...THE HRRR TREND HAS BEEN TOWARDS REDUCED COVERAGE AND
IMPACT FOR THE REMAINDER OF THE EVENING AND OVERNIGHT.

THAT SAID...THERE ARE NUMEROUS CLUES SUGGESTING CONVECTION
PERCOLATING OVER SERN ARIZONA/NRN MEXICO WILL HAVE AN EFFECT ON
SENSIBLE WEATHER ACROSS CNTRL ARIZONA TONIGHT. A WEAK WAVE AND
INCREASINGLY DIFLUENT FLOW SHOULD MOVE NORTH FROM SONORA MEXICO
WHILE A SLUG OF +7C H7 DEWPOINTS ARE CONCURRENTLY ADVECTED INTO THE
FORECAST AREA. MID LEVEL LAPSE RATES ARE MARGINALLY STEEP WITH
NON-ZERO MUCAPE POSSIBLE SHOULD NEAR FULL SATURATION OCCUR AROUND
THE 318K-320K SURFACES. ONGOING CONVECTION MAY AID IN
OUTFLOW/GRAVITY WAVE PROPAGATION TO INVIGORATE FRESH SHOWER
DEVELOPMENT THROUGH CNTRL ARIZONA. CONFIDENCE IS NOT PARTICULARLY
HIGH...BUT FORECAST SOUNDINGS AND ISENTROPIC SURFACES SUGGEST SOME
SHOWER ACTIVITY IS POSSIBLE.

OTHERWISE...MODELS CONTINUE TO POINT TOWARDS AN UNUSUALLY HIGH
CHANCE FOR WIDESPREAD RAINFALL (SOME HEAVY) OVER MUCH OF THE
FORECAST AREA...AND ESPECIALLY FOCUSED THROUGH SERN CALIFORNIA AND
FAR WRN ARIZONA COURTESY OF THE REMNANTS OF IVO. THE MAJORITY OF
HURRICANE FORECAST MODELS AND NAEFS ENSEMBLES STREAM THE CIRCULATION
CENTER ACROSS THE BAJA PENINSULA AND DIRECTLY UP THE COLORADO RIVER
VALLEY. SUBSTANTIAL MOISTURE FLUX WILL ENSUE WITH PWATS AOA 2.1
INCHES (REPRESENTING NORMALIZED STANDARD DEVIATIONS 2-3 ABOVE
NORMAL) WITH WIDESPREAD ASCENT. EXPANDED FLASH FLOOD WATCH TO
INCLUDE ALL OF YUMA COUNTY GIVEN ENSEMBLE MEANS AND SPREAD
JUSTIFYING THIS AREA AS A POTENTIAL TARGET FOR EXCESSIVE RAINFALL.

&&

.PREVIOUS DISCUSSION...
/235 PM MST FRI AUG 23 2013/
THANKS IN LARGE PART TO TROPICAL STORM IVO...LOCATED AT 19.5N 111.8W
AND MOVING NORTHWARD...THE INCREASED MOISTURE WILL CONTINUE THROUGH
THE WEEKEND AND LINGER THROUGH MOST OF THE FOLLOWING WEEK AHEAD.
FORECAST PWAT VALUES 2 TO 2.2 INCHES ACROSS SOUTHWEST ARIZONA PAIRED
WITH DIFFLUENCE ALOFT FROM SATURDAY THROUGH SUNDAY EVENING HELP SET
THE STAGE FOR A VERY MOISTURE RICH ENVIRONMENT. MLCAPE 1000-1300
J/KG AND AN INVERTED TROUGH NOTED BY THE GFS AND NAM WILL PROVIDE
THE DISTURBANCE NEEDED TO KEEP THUNDER MENTION. INITIALLY
THINKING...THUNDERSTORM AND CONVECTIVE ACTIVITY WILL BE A STARTING
POINT AND AS THE ATMOSPHERE BECOMES MORE ENTRAINED WITH
MOISTURE...RAIN SHOWERS MAY LINGER AND STRATIFORM PRECIP WILL OCCUR.
WITH SUCH A MOISTURE RICH ENVIRONMENT AND SLOW STEERING FLOW...A
FLASH FLOOD WATCH HAS BEEN ISSUED FOR THE SOUTHEAST CALIFORNIA AND
SOUTHWEST ARIZONA LOCATIONS FOR THE ENTIRE DAY SUNDAY. WILL HAVE TO
DECIDE IF IT NEEDS TO BE EXTENDED TIME OR SPATIALLY AS CONDITIONS
EVOLVE. FORECAST QPF VALUES MAY RANGE FROM 0.5 TO 1.5 INCHES ACROSS
SOUTHWEST ARIZONA AND LOCALIZED AS HIGH AS 2.5 TO 3 INCHES IN SOME
LOCATIONS INCLUDING SOUTHEAST CALIFORNIA.

LOCAL AND HI-RES MODELS HAVE DONE A NICE JOB TO CONVEY TIMING AND
SPACIAL COVERAGE FOR INITIATION...HOWEVER THE TIMING OF THE HEAVY
RAIN IS STILL SOMEWHAT VAGUE. AS TROPICAL STORM IVO EVOLVES AND
CONTINUES MOVING NORTHWARD...MOISTURE WILL CONTINUE TO STREAM
THROUGH ARIZONA AND INTO NEVADA AND SOUTHERN UTAH. MADE MINOR
CHANGES TO THE POP GRIDS THAT WERE PASSED ALONG...KEEPING THE
GREATEST PERIOD FOR HIGHEST POP VALUES SATURDAY EVENING / 25/00Z /
THROUGH OVERNIGHT SUNDAY / 26/06Z /.

EXTENDED PERIOD...UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND
CONSEQUENTLY I THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM
COVERAGE MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT
FRIDAY WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL
TEMPS GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE
GFS AND EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES
NEXT WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY
PER GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN
PLACE...TUESDAY AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF
THESE TROUGHS ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO
NEED TO BE LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...INCLUDING KPHX...KIWA...KSDL...
THUNDERSTORMS HAVE BEEN STRUGGLING WITH OUTFLOWS STALLING SHORT OF
THE TERMINAL SITES. LATEST THINKING IS SFC WINDS MAY BECOME MORE
VARIABLE BEFORE OBTAINING A PREDOMINANT EASTERLY OVERNIGHT DRIFT.
VIRGA AND LIGHT SHOWERS MAY AFFECT CNTRL ARIZONA OVERNIGHT...THOUGH
CONFIDENCE WAS FAR TOO LOW TO INCLUDE IN TAFS. SHOULD THIS
OCCUR...WINDS MAY BECOME NORTHERLY (OR MORE VARIABLE)
BRIEFLY...THOUGH CIGS SHOULD REMAIN AOA 10K FT. THUNDERSTORM AND
OUTFLOW CHANCES DIRECTLY AFFECTING TERMINAL SITES BECOME FAR HIGHER
LATE SATURDAY AFTERNOON/EVENING...BUT CONFIDENCE IS STILL SHORT OF
ADDING A TEMPO/PROB30 GROUP.

SOUTHEAST CALIFORNIA...INCLUDING KIPL...AND KBLH...
TRANQUIL CONDITIONS AND ONLY HIGH CLOUDS WILL AFFECT SERN CALIFORNIA
TERMINALS THROUGH SATURDAY AFTERNOON...WITH WINDS PREDOMINANTLY S/SE
(THOUGH SOME BRIEF PERIOD OF VARIABLE WINDS ARE POSSIBLE).
THUNDERSTORMS AND OUTFLOW MAY MORE DIRECTLY AFFECT AERODROMES LATE
SATURDAY AFTERNOON/EVENING...THOUGH OVERALL CONFIDENCE IN ADDING ANY
MENTION IN THIS TAF PACKAGE IS TOO LOW AT THIS TIME.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING AZZ020-021-025-026.

CA...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING CAZ030>033.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...MO/DEWEY
AVIATION...HIRSCH
FIRE WEATHER...AJ








AREA FORECAST DISCUSSION

NWS TUCSON AZ

 845 AM MST THU AUG 22 2013

.SYNOPSIS...ISOLATED TO SCATTERED MOSTLY AFTERNOON AND EVENING
THUNDERSTORMS WILL PREVAIL THROUGH FRIDAY. THEREAFTER...INCREASING
MOISTURE FROM THE GULF OF CALIFORNIA WILL PROVIDE MORE COVERAGE OF
THUNDERSTORMS THIS WEEKEND. ABOVE NORMAL DAYTIME TEMPERATURES WILL
CONTINUE THROUGH FRIDAY FOLLOWED BY A COOLING TREND THIS WEEKEND.

&&

.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY INDICATED CLOUDY SKIES
ACROSS WESTERN/CENTRAL PIMA COUNTY AND SOUTH CENTRAL PINAL COUNTY AT
THIS TIME. CLEAR SKIES TO MOSTLY CLEAR SKIES PREVAILED FROM TUCSON
EWD/SWD ACROSS GREENLEE/GRAHAM/COCHISE/SANTA CRUZ COUNTIES.
DEWPOINTS VALID 15Z RANGED GENERALLY FROM THE MID 50S-MID 60S...AND
THESE TEMPS WERE NEARLY IDENTICAL TO 24 HOURS AGO. SURFACE TEMPS
VALID 15Z WERE ABOUT 2-5 DEGS F WARMER VERSUS 24 HOURS AGO.

BLENDED TOTAL PRECIP WATER PRODUCT YIELDED VALUES RANGING FROM 1.10
INCHES NEAR THE NEW MEXICO BORDER TO 1.55 INCHES ACROSS WRN PIMA
COUNTY. 22/12Z KTWC SOUNDING PRECIP WATER VALUE OF 1.47 INCHES WAS
VIRTUALLY UNCHANGED VERSUS 24 HOURS AGO. HOWEVER...HAVE NOTED THE
MARKEDLY DRIER REGIME ABOVE 500 MB VERSUS WED MORNING. THE SOUNDING
SUPPORTS A MARGINALLY UNSTABLE ENVIRONMENT WITH MODIFIED CAPE AROUND
500 J/KG. 22/12Z UPPER AIR PLOTS INDICATED A BROAD RIDGE ACROSS MUCH
OF THE CONUS...AND A 576 DM LOW PRESSURE CENTERED NEAR SAN
FRANCISCO. LIGHT GENERALLY SELY FLOW ALOFT PREVAILED ACROSS SE AZ.

THE OFFICIAL FORECAST WAS UPDATED TO INSERT ISOLATED SHOWERS/TSTMS
THIS MORNING ACROSS WRN PIMA COUNTY AND SOUTH CENTRAL PINAL COUNTY.
OTHERWISE...APPEARS THAT THE FAVORED AREAS FOR SHOWERS/TSTMS THIS
AFTERNOON WILL BE MAINLY NEAR THE MOUNTAINS GIVEN THE VERY WEAK MID-
LEVEL STEERING FLOW. THE LATEST RUC HRRR THEN FAVORS LOCALES SOUTH
AND WEST OF TUCSON FROM LATE THIS AFTERNOON THRU THIS EVENING...
THEN ACROSS WRN/CENTRAL PIMA COUNTY LATE TONIGHT. THIS SCENARIO IS
VERY SIMILAR TO THE INHERITED OFFICIAL FORECAST. THUS...NO ADDITIONAL
GRIDDED DATA POP FIELD ADJUSTMENTS ARE ANTICIPATED AT THIS TIME.
HIGH TEMPS THIS AFTERNOON WILL GENERALLY BE A FEW DEGS ABOVE NORMAL.
PLEASE REFER TO THE PREVIOUS DISCUSSION SECTION BELOW FOR ADDITIONAL
DETAIL.

&&

.PREV DISCUSSION /154 AM MST THU AUG 22 2013/...MODELS INDICATE THAT
THE SWATH OF DRIER AIR WILL FILTER INTO THE REGION FROM THE EAST
TODAY...WHICH WILL HELP TO KEEP THUNDERSTORM ACTIVITY MOSTLY
ISOLATED IN NATURE THIS AFTERNOON AS WELL AS FRIDAY AFTERNOON.
HOWEVER...BY FRIDAY NIGHT INTO SATURDAY A SURGE OF MOISTURE UP THE
GULF OF CALIFORNIA WILL SPILL INTO SOUTHERN ARIZONA AS A WELL
ADVERTISED TROPICAL SYSTEM IS EXPECTED TO PARALLEL THE WEST COAST OF
BAJA THIS WEEKEND AND INTO EARLY NEXT WEEK. AS A RESULT OF THIS
INFLUX OF MOISTURE...EXPECT TO SEE AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY THIS WEEKEND. ONLY MADE MINOR ADJUSTMENTS TO
THE POP GRIDS FOR THIS TIME FRAME. FROM MONDAY ONWARD...SCATTERED
TYPE POPS EXPECTED FOR MOST LOCATIONS AS MOISTURE EXPECTED TO LINGER
THROUGH MID WEEK. HIGHS GENERALLY 2 TO 3 DEGS ABOVE NORMAL TODAY AND
FRIDAY...THEN 3 TO 5 DEGS BELOW NORMAL FOR THE WEEKEND.
THEREAFTER...HIGHS NEAR NORMAL. LOWS GENERALLY 2 TO 3 DEGS ABOVE
NORMAL EACH DAY.

&&

.AVIATION...VALID THRU 12Z 8/23...
AN UPPER LVL LOW ACROSS CENTRAL MEXICO WILL CONTINUE TO USHER IN DRY
MID LVL AIR INTO THE AREAS EAST OF KTUS. THIS WILL LIMIT TS
DEVELOPMENT THIS AFTERNOON...THOUGH ENOUGH MOISTURE AND INSTABILITY
IN PLACE FOR ISOLD DEVELOPMENT. THE MID LVL MOISTURE WILL REMAIN IN
PLACE FROM KOLS W-WARD RESULTING IN BETTER INSTABILITY AFTER 18Z.
WILL CONTINUE TO HANDLE THIS WITH VCSH AS TIMING AND COVERAGE
REMAINS UNCERTAIN. OTHERWISE...VFR CONDITIONS AND LIGHT DIURNAL
WINDS OUTSIDE OF TS OUTFLOW DRIVEN WINDS. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.

&&

.FIRE WEATHER...EXPECT ISOLATED TO SCATTERED MAINLY AFTERNOON AND
EVENING THUNDERSTORMS THROUGH FRIDAY. MOISTURE WILL INCREASE THIS
WEEKEND FOR MORE WIDESPREAD COVERAGE OF SHOWERS AND THUNDERSTORMS.
THE DAILY CYCLE OF SCATTERED MAINLY AFTERNOON AND EVENING
THUNDERSTORMS WILL RETURN BY THE MIDDLE OF NEXT WEEK. OTHERWISE...
ABOVE NORMAL DAYTIME TEMPERATURES WILL OCCUR TODAY AND FRIDAY ALONG
WITH NORMAL DIURNAL WIND TRENDS. A COOLING TREND WILL OCCUR THIS
WEEKEND FOLLOWED BY GRADUALLY WARMER DAYTIME TEMPERATURES EARLY NEXT
WEEK.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON

DISCUSSION/FIRE WEATHER...FRANCIS
PREVIOUS DISCUSSION...MOLLERE
AVIATION...MEADOWS






AREA FORECAST DISCUSSION

NWS GRAND JUNCTION CO

 957 PM MDT FRI AUG 23 2013

.UPDATE...
ISSUED AT 948 PM MDT FRI AUG 23 2013

VERY ACTIVE LATE AFTERNOON AND EARLY EVENING PERIOD ACROSS THE
FORECAST AREA. WIND GUSTS TO NEAR 70 MPH REPORTED NEAR RIFLE WITH
FLASH FLOODING ACROSS INTERSTATE 70 WEST OF PARACHUTE. THIS
PATTERN LOOKS TO REPEAT ITSELF OVER THE NEXT FEW DAYS...WITH
LOCATIONS LIKELY CHANGING.

IN THE MEANTIME...SHOWERS AND THUNDERSTORMS CONTINUE TO LIFT
NORTH ACROSS THE REGION THIS EVENING...ALTHOUGH COVERAGE HAS
DIMINISHED SIGNIFICANTLY OVER THE PAST FEW HOURS. ATMOSPHERE
REMAINS SUFFICIENTLY UNSTABLE TO KEEP A MENTION OF SHOWERS IN
THROUGH THE REMAINDER OF THE NIGHT...SO SOME SLIGHT TWEAKING OF
POPS IN STORE. LATEST HRRR AND RAP13 RUNS BOTH PICKING UP ON
ANOTHER WEAK WAVE LIFTING NORTH INTO THE FOUR CORNERS AROUND 3 AM
WITH ADDITIONAL CONVECTION FIRING. WILL BE MAKING THE BIGGEST
ADJUSTMENTS INTO THE SOUTHERN ZONES TO FIT THIS TREND.
OTHERWISE...NO MAJOR CHANGES IN STORE THE REMAINDER OF THE NIGHT.

&&

.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 408 PM MDT FRI AUG 23 2013

REGIONAL PROFILERS AND WATER VAPOR IMAGERY SHOWING THE UPPER RIDGE
MOVING INTO THE HIGH PLAINS THIS AFTERNOON. SATELLITE ALSO SHOWING A
STRONG TROPICAL AND MONSOONAL TAP SWEEPING INTO THE DESERT SOUTHWEST
AND BEING DRAWN NORTHEASTWARD INTO THE GRADIENT FLOW PRODUCED BY THE
UPPER RIDGE AND LOW PRESSURE APPROACHING THE WEST COAST. WATER VAPOR
AND DYNAMIC TROP PRESSURE FIELDS ALSO SHOWED A VERY DISTINCT PV LOBE
ROTATING THROUGH THE 4 CORNERS THIS MORNING. FOLLOWING THIS IS A
SECOND WAVE LIFTING THROUGH THE MOISTURE PLUME INTO SOUTHEAST UTAH
THIS AFTERNOON. PWATS STILL HOVERING WELL ABOVE NORMAL WHICH WHEN
COMBINED WITH THE INSTABILITY ON THE NOSE OF THE PV LOBE...LED TO A
VIGOROUS OUTBREAK IN THE CONVECTION THIS AFTERNOON. STRONG OUTFLOW
WINDS...HEAVY DOWNPOURS AND EVEN SMALL HAIL WILL CONTINUE TO BE A
THREAT THROUGH THE MID EVENING HOURS.

THE UPPER RIDGE WILL CONTINUE TO SLIDE EASTWARD OVER THE NEXT 24 TO
36 HOURS PULLING THE MOISTURE PLUME OVER CENTRAL UTAH INTO OUR CWA
BEGINNING OVERNIGHT. MODEL THETA SURFACES AT 325K SHOW MOISTURE
ADVECTION LEAVING PWATS UP NEAR AN INCH. WEAK ASCENT WILL ALSO BE
SLIDING ACROSS THE COLORADO/UTAH BORDER AND SHOULD LEAVE ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS DRIFTING NORTHWARD THROUGH THE
OVERNIGHT HOURS. MOISTURE REMAINS IN PLACE OVER OUR CWA GOING INTO
TOMORROW AFTERNOON AND MID LEVEL SHEAR REMAINS STRONG DUE THE
GRADIENT FLOW. THEREFORE ANOTHER ROUND OF CONVECTION LOOKS ON TRACK
AS A SERIES OF TRANSIENT WAVES LOOK TO MOVE THROUGH THE FLOW. STORMS
WILL AGAIN BE ON THE MOVE SO FLOODING SHOULD BE LIMITED TO LOCALIZED
AREAS. THE THREAT OF STRONG WIND GUSTS AND SMALL HAIL WILL BE
POSSIBLE AS WELL. HIGHS LOOK TO BE IMPACTED BY THE MORE ACTIVE
WEATHER AND DID LOWER THEM SLIGHTLY TOWARD THE COOLER MET GUIDANCE.
MOISTURE TRANSPORT VECTORS SHOW A STRONG TAP TO THE TROPICS AGAIN
SATURDAY NIGHT...NOSING INTO THE 4 CORNERS BY SUNRISE ON SUNDAY.
THIS SHOULD KEEP A THREAT OF SHOWERS GOING...WITH THE BEST CHANCES
OVER OUR SOUTHWEST CWA.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 PM MDT FRI AUG 23 2013

DEEP LAYERED MOISTURE ADVECTION FROM IVO AND OLD MEXICO SPREADS
NORTH OVER UTAH ON SUNDAY. FOR OUR FORECAST AREA...THE BEST
ISENTROPIC UPGLIDE AND SPEED SHEAR WILL BE POSITIONED OVER
NORTHEAST UTAH.  PARTS OF WESTERN COLORADO WILL BE ON THE ERN EDGE
OF THIS MOISTURE PLUME. WITH PROGGED PWATS REACHING (POSSIBLY
EXCEEDING) THE CLIMATOLOGICAL EXTREME ON THE HIGH END...THERE IS
CONCERN ON FLASH FLOODING POTENTIAL. ANOTHER WAY TO LOOK AT
THIS...700 MB SPECIFIC HUMIDITY EXCEEDS 10 G/KG FOR THE WRN HALF
OF OUR FORECAST AREA (THAT IS A LOT OF REAL ESTATE FOR SUCH
VALUES). FLOODING POTENTIAL MAY BE MITIGATED BY EXTENSIVE CLOUD
COVER THAT LIMITS CONVECTIVE POTENTIAL...BUT WIDESPREAD
SIGNIFICANT RAINS MAY STILL BRING AN ELEVATED RISK OF FLOODING.
THE FLASH FLOOD POTENTIAL MAY BE POSITIONED FARTHER EAST THAN WHAT
MODEL QPF MAY SUGGEST...CONVECTIVE POTENTIAL MAY BE HIGHER OF THE
ERN EDGE OF THE DEEP MOISTURE FEED DUE TO DIFFERENTIAL HEATING.
GIVEN THE DEEP LAYERED SPEED SHEAR...TRAINING ECHOS MAY OCCUR OVER
THE NERN COLORADO PLATEAU THAT IS MORE PRONE TO FLASH FLOODING.
THIS THREAT EXTENDS INTO MONDAY (POSSIBLY INTO TUESDAY MORNING) AS
DEEP MOISTURE STREAMS ACROSS UTAH. THERE IS STILL SOME UNCERTAINTY
ON HOW THIS EVOLVES AS EACH MODEL SHOWS DIFFERENT QPF AMOUNTS...BUT
THEY ALL ARE WET AND THEREFORE FORECASTS SHOULD STRONGLY LEAN
TOWARD A SIGNIFICANT RAIN EPISODE ACROSS THE NERN HALF OF OUR
FORECAST AREA.  GIVEN THE ANOMALY OF THIS EVENT...WITH
COORDINATION WITH SLC AND WPC DAY 3 GUIDANCE...WILL ISSUE A RARE
DAY 2 AND DAY 3 FLASH FLOOD WATCH FOR EASTERN UTAH FROM SUNDAY
AFTERNOON THROUGH MONDAY AFTERNOON.

WEDNESDAY THROUGH FRIDAY...NOT AS WET BUT THE RAIN PROBABILITIES
REMAIN ABOVE CLIMOTOLOGICAL NORM. AIR MASS REMAINS CONDITIONALLY
UNSTABLE WITH SCATTERED STORMS OVER THE HIGHER TERRAIN. SUFFICIENT
MID LEVEL FOR A FEW OF THESE STORMS TO MOVE ACROSS THE LOWER
VALLEYS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 948 PM MDT FRI AUG 23 2013

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE
ACROSS EASTERN UTAH AND WESTERN COLORADO THROUGH 06Z SATURDAY
NIGHT. THE MOST SIGNIFICANT STORMS WILL BE FOUND BETWEEN 18Z
SATURDAY AND 03Z SUNDAY...WITH DIMINISHED COVERAGE ON EITHER SIDE
OF THAT WINDOW. THUNDERSTORMS WILL PRODUCE GUSTY OUTFLOW WINDS TO
NEAR 50 MPH AND VERY HEAVY RAINFALL. EXPECT CIGS AND VSBYS TO DROP
INTO THE IFR CATEGORY FOR BRIEF PERIODS OF TIME AS THE STRONGEST
STORMS MOVE THROUGH.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.

UT...FLOOD WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON FOR
     UTZ022>025-027>029.

&&

$$

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







AREA FORECAST DISCUSSION

NWS PUEBLO CO

 1105 PM MDT WED AUG 21 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 347 PM MDT WED AUG 21 2013

...FLASH FLOODING/LANDSPOUT THREAT INCREASING...ESPECIALLY FOR
TOMORROW...

CURRENTLY...

SHOWERS AND STORMS ARE MORE ABUNDANT THEN THIS TIME YESTERDAY...WITH
HUNDREDS OF CG STRIKES OCCURRING DURING THE LAST HOUR OVER THE STATE.
A SFC BOUNDARY IS SEEN IN THE MOSAIC RADAR DATA EXTENDING ACROSS
EAST CENTRAL CO AND BECOMING DIFFUSE OVER THE WESTERN PALMER DIVIDE
REGION. TEMPS HAVE RISEN WELL INTO THE 90S ACROSS THE PLAINS...WITH
TEMPS APPROACHING 100 OUT NEAR KLAA.

REST OF TODAY AND TONIGHT...

UPPER MOISTURE WILL CONTINUE TO INCREASE AND EXPECT SCTD SHOWERS AND
STORMS OVER THE HIGHER TRRN THROUGHOUT THIS AFTERNOON. HRRR IS A BIT
AGGRESSIVE OVER THE PIKES PEAK REGION THIS AFTERNOON AND WILL HAVE
TO WATCH THIS AREA FOR FLASH FLOOD PROBLEMS. THE HRRR AGRESSIVENESS
MAY BE IN RESPONSE TO THE BOUNDARY MENTIONED ABOVE. DWPTS HAVE BEEN
MIXING OUT A BIT BUT 30S AND 40S WERE STILL NOTED ACROSS THE
MTNS...WITH 40S AND 50S OVER THE PLAINS. WE WILL ALSO SEE A BETTER
CHANCE OF TSRA OVER THE PLAINS LATE THIS
AFTERNOON/EVENING...ESPECIALLY OVER THE PALMER DVD AND RATON MESA
REGION. WITH THE BOUNDARY OVER THE PALMER...MAY HAVE TO WATCH OUT
FOR A LANDSPOUT...ALBEIT THE PROBABILITY OF THIS IS LOW.

LATER TONIGHT I ANTICIPATE IT TO BE MAINLY DRY WITH PARTLY CLOUDY
SKIES.

THURSDAY...

BY TOMORROW AFTERNOON...BOUNDARY SHOULD LIE FROM KTAD TO NEAR KLAA.
NORTH OF THE FRONT...MOIST UPSLOPE FLOW WILL BE IN PLACE AND WE WILL
SEE A BETTER CHANCE OF STORMS OVER THE PLAINS. WITH THE BOUNDARY
OVER FAR SE CO...A BETTER CHANCE OF A LANDSPOUT TORNADO WILL BE
POSSIBLE...ESPECIALLY CONSIDERING THIS BOUNDARY WILL BE "COOKING"
ALL DAY TOMORROW AND CAPES SHOULD BE ABOUT 1000 J/KG AND WINDS
THROUGHOUT THE COLUMN WILL BE LIGHT.

FLASH FLOOD THREAT OVER THE BURN SCARS WILL BE HIGHER TOMORROW AS
MOISTURE WILL BE MORE ABUNDANT THROUGHOUT THE COLUMN...CAPES WILL BE
ABOUT 1500-2000 ACROSS THE PIKES PEAK REGION AND FLOW WILL BE RATHER
WEAK. THE LOCAL WRF HAS OVER AN INCH OF RAIN OVER THE WALDO LATE
TOMORROW AFTERNOON. CONTEMPLATED ON ISSUING A FLASH FLOOD WATCH BUT
THOUGHT IT BEST TO LET THE MID CREW ISSUE AS THEY WILL HAVE A COUPLE
MORE GUIDANCE RUNS TO LOOK AT.

EXPECT MAX TEMPS TO BE COOLER TOMORROW AS WE WILL SEE MORE CLOUDS
AND LOW LVL MOISTURE OVER THE REGION. HIGHS SHOULD ONLY BE IN THE
90-96F RANGE OVER THE PLAINS...WITH U80S OVER THE PALMER/RATON MESA
REGION. /HODANISH

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 347 PM MDT WED AUG 21 2013

LONGER TERM METEOROLOGICAL ISSUES REMAIN POPS AND TEMPERATURES.

SOME ADJUSTMENTS NEEDED FOR LONGER CYCLE AS UPPER RIDGE IS NOW
PROJECTED TO NOT PUSH AS FAR EAST AS EARLIER INDICATED...MEANING
THAT PRIMARY MOISTURE PLUME SHOULD REMAIN OVER WESTERN PORTIONS OF
THE FORECAST DISTRICT AND POINTS WEST DURING THE LONGER TERM.

THE UPPER RIDGE OF HIGH PRESSURE CENTERED OVER SOUTHERN COLORADO
THIS AFTERNOON IS STILL EXPECTED TO BECOME CENTERED OVER KANSAS
AND OKLAHOMA BY LATER FRIDAY NIGHT BEFORE SHIFTING INTO
MISSOUR(INSTEAD OF OVER ILLINOIS AS SOME PREVIOUS MODEL RUNS HAVE
INDICATED) BY WEDNESDAY.

AS THE UPPER RIDGE PUSHES EAST...FORECAST DISTRICT SHOULD STILL
EXPERIENCE INCREASING ATMOSPHERIC MOISTURE VALUES AT TIMES
...ESPECIALLY OVER WESTERN HIGHER TERRAIN LOCATIONS DURING THE
LONGER TERM.

AT THIS TIME...IT APPEARS THAT THE PRIMARY DEEPER MOISTURE FROM
THE DEEP TROPICS OFF THE WEST COAST OF MEXICO SHOULD REMAIN
FOCUSED OVER THE NEW MEXICO...UTAH AND WESTERN COLORADO REGION FROM
THIS WEEKEND INTO EARLY NEXT WEEK...THEREFORE WESTERN BURN SCARS
SUCH AS THE WEST FORK COMPLEX SHOULD NOTE THE HIGHEST POTENTIAL OF
BURN SCAR FLASH FLOODING DURING THIS TIME-FRAME. WFO PUEBLO WILL
CONTINUE TO MONITOR THIS POTENTIAL TREND CLOSELY.

FINALLY...CONTINUED ABOVE SEASONAL LATE AUGUST TEMPERATURES(ESPECIALLY
EASTERN SECTIONS) AS WELL AS GENERALLY LOW-GRADE GRADIENT WINDS

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1105 PM MDT WED AUG 21 2013

MAINLY VFR CONDITIONS EXPECTED AT TAF SITES THROUGH THE NEXT 24
HOURS. COULD SEE -SHRA AT ALS FOR THE NEXT FEW HOURS AS CONVECTIVE
DEBRIS CLOUDS SLOWLY DIMINISH ACROSS THE STATE THOUGH THE OVERNIGHT.

MONSOONAL MOISTURE WILL CONTINUE TO INCREASE ACROSS THE AREA
THROUGH THE DAY TOMORROW WITH MORE SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED ACROSS THE HIGHER TERRAIN IN THE AFTERNOON
AND EVENING HOURS. IN ADDITION...A SECONDARY SURGE OF COOLER AIR
WILL MOVE ACROSS THE EASTERN PLAINS TOMORROW MORNING...WITH LOW LEVEL
MOISTURE INCREASING WITHIN THE DEVELOPING UPSLOPE FLOW. THIS WILL
LEAD TO BETTER CHANCES OF BRIEF MVFR AND IFR CONDITIONS AT COS AFT
20Z WITH LOCALLY HEAVY RAINFALL POSSIBLE.

&&

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

$$

AVIATION...MW







AREA FORECAST DISCUSSION

NWS ALBANY NY

 942 PM EDT FRI AUG 23 2013

.SYNOPSIS...
HIGH PRESSURE WILL BUILD EASTWARD FROM THE GREAT LAKES REGION INTO
THE NORTHEAST THROUGH SATURDAY...WITH A NORTHERLY FLOW BRINGING
COOLER TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS. THE SURFACE
HIGH PRESSURE SYSTEM WILL DRIFT EAST OF NEW JERSEY ON SUNDAY WITH
CONTINUED FAIR WEATHER...BUT WITH A SOUTHWEST FLOW AND SLIGHTLY
WARMER TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 930 PM...SKIES HAVE BECOME CLEAR ACROSS MOST OF THE REGION BUT
STILL PARTLY CLOUDY OVER THE CATSKILLS. WILL ADJUST SKY COVER GRIDS
TO CLEAR IN MOST AREAS OVERNIGHT...AND MOSTLY CLEAR OVER THE
CATSKILLS. HAVE ALSO MADE SOME ADJUSTMENTS TO THE HOURLY TEMP GRIDS
IN ORDER TO ACCOUNT FOR CURENT CONDITIONS.


.PREVIOUS DISCUSSION...
EXPECT MOSTLY CLEAR TO CLEAR SKIES FOR THE OVERNIGHT HOURS. THE
LATEST RUC13 SUGGESTS A SECONDARY SURGE OF LOW LEVEL...DRY AIR
ADVECTING SOUTHWARD EARLY TONIGHT. THIS MAY ACT TO KEEP THE BOUNDARY
LAYER SOMEWHAT MIXED...PARTICULARLY IN THE HUDSON VALLEY
REGION...WITH A N/NE WIND PERSISTING WELL INTO THE OVERNIGHT
HOURS...WHICH MAY PRECLUDE FOG FORMATION AND ALSO VERY COOL TEMPS
FROM OCCURRING. THEREFORE...HAVE KEPT OUT MENTION OF PATCHY
FOG...AND HAVE INDICATED MIN TEMPS IN THE MID 40S TO LOWER 50S IN
MOST AREAS...WITH SOME LOWER 40S POSSIBLE ACROSS PORTIONS OF THE
WESTERN ADIRONDACKS.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
SAT-SUN...HIGH PRESSURE SHOULD PROVIDE GENERALLY CLEAR/SUNNY SKIES
FOR SAT...WITH JUST OCCASIONAL PASSING HIGH CLOUDS POSSIBLE LATE
SAT NT INTO SUNDAY. MIXING DEPTHS MAY BE SOMEWHAT SHALLOW FOR
SAT...COMPARED TO RECENT DAYS...GENERALLY UP TO BETWEEN 900 AND
875 MB. THIS SHOULD ALLOW FOR MAX TEMPS TO REACH 75-80 IN MOST
VALLEY AREAS...AND UPPER 60S TO LOWER/MID 70S ACROSS HIGHER
ELEVATIONS. FOR SAT NT/SUN AM...MIN TEMPS COULD BE A BIT COOLER
THAN TONIGHT...ESP SHOULD ANY HIGH CLOUDS HOLD OFF OR REMAIN VERY
THIN. HOWEVER...WITH LESS MIXING AND WIND COMPARED TO
TONIGHT...THE POTENTIAL FOR AT LEAST PATCHY GROUND FOG WILL BE
GREATER...WHICH COULD KEEP AREAS IMMEDIATELY ADJACENT TO BODIES OF
WATER A BIT WARMER. HAVE GENERALLY SIDED A BIT CLOSER TO THE
COOLER MAV MOS IN MOST AREAS...WITH MIN TEMPS FALLING INTO THE MID
40S TO LOWER 50S IN MOST VALLEY AREAS...AND MAINLY LOWER/MID 40S
ACROSS HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND...AND THE
EASTERN CATSKILLS/WESTERN ADIRONDACKS. ACROSS SOME SHELTERED
PORTIONS OF THE SOUTHERN ADIRONDACKS...AND EASTERN
CATSKILLS...SOME UPPER 30S COULD EVEN OCCUR BY DAYBREAK SUNDAY.
AFTER THE CHILLY START...EXPECT SLIGHTLY DEEPER MIXING WITH A
DEVELOPING SOUTHWEST LOW LEVEL FLOW TO ALLOW FOR WARMER MAX TEMPS
ON SUNDAY...WITH UPPER 70S TO LOWER 80S IN MOST VALLEYS...AND
70-75 FOR HIGHER ELEVATIONS.

SUN NT-MON NT...FORECAST UNCERTAINTY INCREASES DURING THIS PERIOD
AS LOW/MID LEVEL WARM ADVECTION STRENGTHENS LATE SUN NT INTO
MONDAY...IN RESPONSE TO A POTENTIAL MID LEVEL DISTURBANCE
APPROACHING FROM THE GREAT LAKES REGION. THIS PATTERN SHOULD ALLOW
FOR INCREASING CLOUDS LATE SUN NT...WITH THE POSSIBILITY OF
SHOWERS FOR MON-MON NT. SOME THUNDERSTORMS COULD OCCUR AS
WELL...ESP LATE MON INTO MON NT AS ELEVATED INSTABILITY DEVELOPS.
EXPECT OVERNIGHT MIN TEMPS TO BE WARMER...WITH MAINLY LOWER/MID
60S FOR VALLEY AREAS...AND 55-60 ACROSS HIGHER ELEVATIONS. MON MAX
TEMPS SHOULD REACH THE MID 70S TO LOWER 80S...ALTHOUGH SHOULD
WIDESPREAD SHOWERS OR A PERIOD OF STEADIER RAIN OCCUR...EVEN
COOLER MAX TEMPS COULD OCCUR.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A CONTINUOUS PATTERN OF DISTURBANCES THAT ARE POTENTIAL RIDGE
ROLLERS SHOULD FLOW FROM NORTHWEST TO SOUTHEAST ON THE NORTHEAST
SIDE OF A BROAD UPPER LEVEL HIGH PRESSURE...CENTERED OVER THE
CENTRAL PLAINS...WHICH WILL AFFECT OUR WEATHER FOR THE EXTENDED
PERIOD. CURRENT THINKING IS THAT THE 12Z MODELS ARE A BIT
DISORGANIZED DUE TO THE EXTENT OF THE RIDGE ITSELF THAT WILL DICTATE
THE SYNOPTIC TRACK OF THESE LOW PRESSURE IMPULSES AS THEY MOVE ON
THE OUTSKIRTS OF THE HIGH PRESSURE SYSTEM. CHANCE POPS WILL BE
THROUGHOUT THE EXTENDED PERIOD TO INCORPORATE THE DIFFERENT
PROBABILITY BLENDS IN THE FORECAST. OUR BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH AN UPPER LEVEL POSITIVE TILTED TROUGH
WITH A POSSIBLE DEVELOPING SURFACE LOW PRESSURE NEAR THE US/CANADA
BORDER WILL BE ON WEDNESDAY NIGHT INTO THURSDAY MORNING. THE GENERAL
CONSENSUS AS OF NOW SHOWS CLEARING IN THE AREA LATE THURSDAY MORNING
AS THE RIDGE FROM THE CENTRAL PLAINS SHIFTS EAST AND HAS MORE OF AN
INFLUENCE ON OUR WEATHER PATTERN...GIVING TRANQUIL CONDITIONS FOR
THE DAY ON FRIDAY. A WARM UP TO ABOVE AVERAGE TEMPERATURES GOING
FROM FRIDAY INTO NEXT WEEKEND IS POSSIBLE AS THE RIDGE CONTINUES TO
MOVE EAST NORTHEAST INTO OUR REGION.

HIGH TEMPERATURES THROUGHOUT THE EXTENDED PERIOD WILL RANGE FROM
THE MID AND UPPER 70S IN THE HIGH TERRAIN TO LOWER 80S IN VALLEY
LOCATIONS. LOW TEMPERATURES WILL RANGE FROM THE UPPER 50S TO MID 60S
FOR THE ENTIRE REGION.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THE MAJORITY OF THE UPCOMING TAF PERIOD WILL BE VFR WITH MAINLY P6SM
SKC CONDITIONS. SOME MORNING FOG IS POSSIBLE AT KGFL AND KPSF...
WHERE IT COULD BE LOCALLY DENSE RESULTING IN IFR CONDITIONS...AND
HAVE FORECAST TEMPO GROUPS FOR IFR FOG BETWEEN 06Z AND 10Z. AT
KPOU/KALB FOG IS NOT EXPECTED BUT HAVE INCLUDED A TEMPO GROUP FOR
MVFR FOG AT KPOU. NORTH TO NORTHEAST WINDS OF 5 TO 10 KTS THIS
EVENING WILL BECOME LIGHTER LATER TONIGHT...THEN REMAIN NORTH TO
NORTHEAST AT LESS THAN 10 KTS ON SATURDAY.

OUTLOOK...

SATURDAY NIGHT: NO OPERATIONAL IMPACT. PATCHY FG.
SUNDAY: NO OPERATIONAL IMPACT.  NO SIG WX.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. ISOLATED SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE ANTICIPATED THE NEXT FEW DAYS. HIGH
PRESSURE WILL BUILD EASTWARD FROM THE GREAT LAKES REGION AND
SOUTHEASTERN CANADA ACROSS THE NORTHEAST TODAY INTO
SATURDAY...WITH COOLER TEMPERATURES AND COMFORTABLE HUMIDITY
LEVELS. THE SURFACE ANTICYCLONE WILL DRIFT SOUTH AND EAST OF THE
NORTHEAST ON SUNDAY WITH TEMPERATURES MODERATING SLIGHTLY ABOVE
NORMAL WITH CONTINUED FAIR WEATHER.

RELATIVE HUMIDITY VALUES WILL RECOVER TO 90 TO 100 PERCENT
TONIGHT WITH SOME DEW FORMATION POSSIBLE. THE RH VALUES WILL FALL
TO 30 TO 45 PERCENT SATURDAY AFTERNOON...THEN RECOVER TO 90-100
PERCENT FOR SAT NT WITH WIDESPREAD DEW FORMATION LIKELY.

NORTH TO NORTHEAST WINDS AT 10-15 MPH WILL DECREASE TO 5-10 MPH
OVERNIGHT. WINDS WILL BE NORTHEAST TO EAST AT 5-15 MPH
SATURDAY...THEN BECOME LIGHT AND VARIABLE FOR SAT NT.

&&

.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH THE WEEKEND. THE WEATHER BECOMES
MORE UNSETTLED SUNDAY NIGHT INTO TUESDAY WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS AS A LOW PRESSURE SYSTEM AND ITS
ASSOCIATED FRONTAL BOUNDARIES APPROACHES FROM THE GREAT LAKES
REGION. PRECIPITATION AMOUNTS WILL BE HIGHLY VARIABLE DEPENDING ON
ANY CONVECTION.

OVERALL FOR THE NEXT 5 DAYS...NO WIDESPREAD HYDRO PROBLEMS ARE
EXPECTED. RIVER FLOWS...AND RESERVOIR LEVELS CONTINUE AT NORMAL TO
SLIGHTLY BELOW NORMAL LEVELS FOR LATE AUGUST.

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

&&

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

&&

$$
SYNOPSIS...GJM/KL
NEAR TERM...GJM/KL
SHORT TERM...KL
LONG TERM...LFM
AVIATION...GJM
FIRE WEATHER...KL/WASULA
HYDROLOGY...KL/WASULA














AREA FORECAST DISCUSSION

NWS ALBANY NY

 800 PM EDT FRI AUG 23 2013

.SYNOPSIS...
HIGH PRESSURE WILL BUILD EASTWARD FROM THE GREAT LAKES REGION INTO
THE NORTHEAST THROUGH SATURDAY...WITH A NORTHERLY FLOW BRINGING
COOLER TEMPERATURES AND COMFORTABLE HUMIDITY LEVELS. THE SURFACE
HIGH PRESSURE SYSTEM WILL DRIFT EAST OF NEW JERSEY ON SUNDAY WITH
CONTINUED FAIR WEATHER...BUT WITH A SOUTHWEST FLOW AND SLIGHTLY
WARMER TEMPERATURES.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 730 PM...SKIES HAVE BECOME MOSTLY CLEAR ACROSS THE REGION AND
HAVE LOWERED THE AMOUNT OF CLOUD COVER IN THE SKY GRIDS FROM WHAT
HAD PREVIOUSLY BEEN FORECAST. HAVE ALSO MADE SOME ADJUSTMENTS TO THE
HOURLY TEMP GRIDS IN ORDER TO ACCOUNT FOR CURENT CONDITIONS.


.PREVIOUS DISCUSSION...
EXPECT MOSTLY CLEAR TO CLEAR SKIES FOR THE OVERNIGHT HOURS. THE
LATEST RUC13 SUGGESTS A SECONDARY SURGE OF LOW LEVEL...DRY AIR
ADVECTING SOUTHWARD EARLY TONIGHT. THIS MAY ACT TO KEEP THE BOUNDARY
LAYER SOMEWHAT MIXED...PARTICULARLY IN THE HUDSON VALLEY
REGION...WITH A N/NE WIND PERSISTING WELL INTO THE OVERNIGHT
HOURS...WHICH MAY PRECLUDE FOG FORMATION AND ALSO VERY COOL TEMPS
FROM OCCURRING. THEREFORE...HAVE KEPT OUT MENTION OF PATCHY
FOG...AND HAVE INDICATED MIN TEMPS IN THE MID 40S TO LOWER 50S IN
MOST AREAS...WITH SOME LOWER 40S POSSIBLE ACROSS PORTIONS OF THE
WESTERN ADIRONDACKS.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
SAT-SUN...HIGH PRESSURE SHOULD PROVIDE GENERALLY CLEAR/SUNNY SKIES
FOR SAT...WITH JUST OCCASIONAL PASSING HIGH CLOUDS POSSIBLE LATE
SAT NT INTO SUNDAY. MIXING DEPTHS MAY BE SOMEWHAT SHALLOW FOR
SAT...COMPARED TO RECENT DAYS...GENERALLY UP TO BETWEEN 900 AND
875 MB. THIS SHOULD ALLOW FOR MAX TEMPS TO REACH 75-80 IN MOST
VALLEY AREAS...AND UPPER 60S TO LOWER/MID 70S ACROSS HIGHER
ELEVATIONS. FOR SAT NT/SUN AM...MIN TEMPS COULD BE A BIT COOLER
THAN TONIGHT...ESP SHOULD ANY HIGH CLOUDS HOLD OFF OR REMAIN VERY
THIN. HOWEVER...WITH LESS MIXING AND WIND COMPARED TO
TONIGHT...THE POTENTIAL FOR AT LEAST PATCHY GROUND FOG WILL BE
GREATER...WHICH COULD KEEP AREAS IMMEDIATELY ADJACENT TO BODIES OF
WATER A BIT WARMER. HAVE GENERALLY SIDED A BIT CLOSER TO THE
COOLER MAV MOS IN MOST AREAS...WITH MIN TEMPS FALLING INTO THE MID
40S TO LOWER 50S IN MOST VALLEY AREAS...AND MAINLY LOWER/MID 40S
ACROSS HIGHER ELEVATIONS ACROSS WESTERN NEW ENGLAND...AND THE
EASTERN CATSKILLS/WESTERN ADIRONDACKS. ACROSS SOME SHELTERED
PORTIONS OF THE SOUTHERN ADIRONDACKS...AND EASTERN
CATSKILLS...SOME UPPER 30S COULD EVEN OCCUR BY DAYBREAK SUNDAY.
AFTER THE CHILLY START...EXPECT SLIGHTLY DEEPER MIXING WITH A
DEVELOPING SOUTHWEST LOW LEVEL FLOW TO ALLOW FOR WARMER MAX TEMPS
ON SUNDAY...WITH UPPER 70S TO LOWER 80S IN MOST VALLEYS...AND
70-75 FOR HIGHER ELEVATIONS.

SUN NT-MON NT...FORECAST UNCERTAINTY INCREASES DURING THIS PERIOD
AS LOW/MID LEVEL WARM ADVECTION STRENGTHENS LATE SUN NT INTO
MONDAY...IN RESPONSE TO A POTENTIAL MID LEVEL DISTURBANCE
APPROACHING FROM THE GREAT LAKES REGION. THIS PATTERN SHOULD ALLOW
FOR INCREASING CLOUDS LATE SUN NT...WITH THE POSSIBILITY OF
SHOWERS FOR MON-MON NT. SOME THUNDERSTORMS COULD OCCUR AS
WELL...ESP LATE MON INTO MON NT AS ELEVATED INSTABILITY DEVELOPS.
EXPECT OVERNIGHT MIN TEMPS TO BE WARMER...WITH MAINLY LOWER/MID
60S FOR VALLEY AREAS...AND 55-60 ACROSS HIGHER ELEVATIONS. MON MAX
TEMPS SHOULD REACH THE MID 70S TO LOWER 80S...ALTHOUGH SHOULD
WIDESPREAD SHOWERS OR A PERIOD OF STEADIER RAIN OCCUR...EVEN
COOLER MAX TEMPS COULD OCCUR.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A CONTINUOUS PATTERN OF DISTURBANCES THAT ARE POTENTIAL RIDGE
ROLLERS SHOULD FLOW FROM NORTHWEST TO SOUTHEAST ON THE NORTHEAST
SIDE OF A BROAD UPPER LEVEL HIGH PRESSURE...CENTERED OVER THE
CENTRAL PLAINS...WHICH WILL AFFECT OUR WEATHER FOR THE EXTENDED
PERIOD. CURRENT THINKING IS THAT THE 12Z MODELS ARE A BIT
DISORGANIZED DUE TO THE EXTENT OF THE RIDGE ITSELF THAT WILL DICTATE
THE SYNOPTIC TRACK OF THESE LOW PRESSURE IMPULSES AS THEY MOVE ON
THE OUTSKIRTS OF THE HIGH PRESSURE SYSTEM. CHANCE POPS WILL BE
THROUGHOUT THE EXTENDED PERIOD TO INCORPORATE THE DIFFERENT
PROBABILITY BLENDS IN THE FORECAST. OUR BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH AN UPPER LEVEL POSITIVE TILTED TROUGH
WITH A POSSIBLE DEVELOPING SURFACE LOW PRESSURE NEAR THE US/CANADA
BORDER WILL BE ON WEDNESDAY NIGHT INTO THURSDAY MORNING. THE GENERAL
CONSENSUS AS OF NOW SHOWS CLEARING IN THE AREA LATE THURSDAY MORNING
AS THE RIDGE FROM THE CENTRAL PLAINS SHIFTS EAST AND HAS MORE OF AN
INFLUENCE ON OUR WEATHER PATTERN...GIVING TRANQUIL CONDITIONS FOR
THE DAY ON FRIDAY. A WARM UP TO ABOVE AVERAGE TEMPERATURES GOING
FROM FRIDAY INTO NEXT WEEKEND IS POSSIBLE AS THE RIDGE CONTINUES TO
MOVE EAST NORTHEAST INTO OUR REGION.

HIGH TEMPERATURES THROUGHOUT THE EXTENDED PERIOD WILL RANGE FROM
THE MID AND UPPER 70S IN THE HIGH TERRAIN TO LOWER 80S IN VALLEY
LOCATIONS. LOW TEMPERATURES WILL RANGE FROM THE UPPER 50S TO MID 60S
FOR THE ENTIRE REGION.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
THE MAJORITY OF THE UPCOMING TAF PERIOD WILL BE VFR WITH MAINLY P6SM
SKC CONDITIONS. SOME MORNING FOG IS POSSIBLE AT KGFL AND KPSF...
WHERE IT COULD BE LOCALLY DENSE RESULTING IN IFR CONDITIONS...AND
HAVE FORECAST TEMPO GROUPS FOR IFR FOG BETWEEN 06Z AND 10Z. AT
KPOU/KALB FOG IS NOT EXPECTED BUT HAVE INCLUDED A TEMPO GROUP FOR
MVFR FOG AT KPOU. NORTH TO NORTHEAST WINDS OF 5 TO 10 KTS THIS
EVENING WILL BECOME LIGHTER LATER TONIGHT...THEN REMAIN NORTH TO
NORTHEAST AT LESS THAN 10 KTS ON SATURDAY.

OUTLOOK...

SATURDAY NIGHT: NO OPERATIONAL IMPACT. PATCHY FG.
SUNDAY: NO OPERATIONAL IMPACT.  NO SIG WX.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.
TUESDAY NIGHT: LOW OPERATIONAL IMPACT. ISOLATED SHRA...TSRA.
WEDNESDAY: MODERATE OPERATIONAL IMPACT. SCATTERED SHRA...TSRA.

&&

.FIRE WEATHER...
NO FIRE WEATHER PROBLEMS ARE ANTICIPATED THE NEXT FEW DAYS. HIGH
PRESSURE WILL BUILD EASTWARD FROM THE GREAT LAKES REGION AND
SOUTHEASTERN CANADA ACROSS THE NORTHEAST TODAY INTO
SATURDAY...WITH COOLER TEMPERATURES AND COMFORTABLE HUMIDITY
LEVELS. THE SURFACE ANTICYCLONE WILL DRIFT SOUTH AND EAST OF THE
NORTHEAST ON SUNDAY WITH TEMPERATURES MODERATING SLIGHTLY ABOVE
NORMAL WITH CONTINUED FAIR WEATHER.

RELATIVE HUMIDITY VALUES WILL RECOVER TO 90 TO 100 PERCENT
TONIGHT WITH SOME DEW FORMATION POSSIBLE. THE RH VALUES WILL FALL
TO 30 TO 45 PERCENT SATURDAY AFTERNOON...THEN RECOVER TO 90-100
PERCENT FOR SAT NT WITH WIDESPREAD DEW FORMATION LIKELY.

NORTH TO NORTHEAST WINDS AT 10-15 MPH WILL DECREASE TO 5-10 MPH
OVERNIGHT. WINDS WILL BE NORTHEAST TO EAST AT 5-15 MPH
SATURDAY...THEN BECOME LIGHT AND VARIABLE FOR SAT NT.

&&

.HYDROLOGY...
DRY WEATHER IS EXPECTED THROUGH THE WEEKEND. THE WEATHER BECOMES
MORE UNSETTLED SUNDAY NIGHT INTO TUESDAY WITH ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS AS A LOW PRESSURE SYSTEM AND ITS
ASSOCIATED FRONTAL BOUNDARIES APPROACHES FROM THE GREAT LAKES
REGION. PRECIPITATION AMOUNTS WILL BE HIGHLY VARIABLE DEPENDING ON
ANY CONVECTION.

OVERALL FOR THE NEXT 5 DAYS...NO WIDESPREAD HYDRO PROBLEMS ARE
EXPECTED. RIVER FLOWS...AND RESERVOIR LEVELS CONTINUE AT NORMAL TO
SLIGHTLY BELOW NORMAL LEVELS FOR LATE AUGUST.

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

&&

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

&&

$$
SYNOPSIS...GJM/KL
NEAR TERM...GJM/KL
SHORT TERM...KL
LONG TERM...LFM
AVIATION...GJM
FIRE WEATHER...KL/WASULA
HYDROLOGY...KL/WASULA











AREA FORECAST DISCUSSION

NWS NEW YORK NY

 549 PM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT WILL APPROACH THIS EVENING AND MOVE ACROSS OVERNIGHT.
HIGH PRESSURE WILL THEN BUILD IN FROM FRIDAY THROUGH SUNDAY...AND
SETTLE TO THE SOUTH ON MONDAY. A SERIES OF FRONTS WILL MOVE ACROSS
THROUGH THE MID TO LATE PORTION OF NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
MUCH OF THE CWA HAS BEEN WORKED OVER THIS EVE. OUTSIDE OF A FEW
RESIDUAL SPRINKLES OVER THE E END OF LI...RADAR IS QUIET. THE
FRONT IS STILL ONLY ACROSS CNTRL NYSTATE.

THERE IS LIKELY SOME WEAK SUBSIDENCE IN THE WAKE OF THE SUBTLE MID
LVL SHRTWV PASSING OVER THE CWA. FOR THIS REASON...DROPPED PCPN
CHCS TIL ABOUT 00Z WHEN CONDITIONS WILL AGAIN BECOME FAVORABLE FOR
DEVELOPMENT AHEAD OF THE FRONT. EXTREME NWRN ZONES STILL HAVE OVER
2K J/KG OF SBCAPE.

CONVECTION WITH ACTUAL COLD FRONT IS FCST BY 17Z HRRR TO WEAKEN
VIA NIGHTTIME COOLING/STABILIZATION. LEFT IN SLIGHT CHANCE POP IN
SOME AREAS AFTER MIDNIGHT IN CASE ANY OF IT SHOULD SURVIVE THIS
FAR EAST. MOCLDY SKIES SHOULD CLEAR LATE AFTER FROPA...WITH LOWS
MAINLY 65-70.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/...
DRIER AIR WILL MOVE IN ON A N-NW BREEZE...WITH DEWPOINTS DROPPING
INTO THE 50S. HIGHS ON FRIDAY WILL REACH THE MID/UPPER 80S.
MOCLEAR SKIES AND DIMINISHING WINDS AS THE HIGH BUILDS OHD WILL
LEAD TO A COOLER NIGHT...WITH LOWER FRI NIGHT FROM THE MID 50S TO
MID 60S. EXCEPTION TO THIS MAY BE ACROSS LONG ISLAND...WHERE NWP
GUIDANCE HAS ADVERTISED MORE IN THE WAY OF CLOUDS AND POSSIBLE A
FEW LATE NIGHT SHOWERS AS AN UPPER LEVEL VORT MAX MOVES ACROSS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
MAIN CONTROLLING FEATURE ACROSS THE US WILL BE THE LARGE UPPER RIDGE
ACROSS THE CENTRAL US...WHICH WILL BUILD SLIGHTLY EASTWARD TOWARDS
THE EASTERN US BY THE END OF THE WEEKEND. THIS WILL PLACE THE REGION
ON THE NE EDGE OF UPPER RIDGING AND IN THE PATH OF A QUICK UPPER
FLOW FOR MUCH OF NEXT WEEK...WITH A SERIES OF WEAK DISTURBANCE
PASSING THROUGH THE NE.

AT THE SURFACE CANADIAN HIGH PRESSURE WILL BUILD INTO AND THEN SLIDE
ACROSS THE REGION THROUGH THE WEEKEND...PROVIDING FAIR AND
SEASONABLY WARM DAYTIME TEMPS. OVERNIGHT LOWS WILL LIKELY BE A BIT
CHILLY ACROSS FAR OUTLYING AREAS SAT NIGHT WITH GOOD RADIATIONAL
COOLING CONDS...PERHAPS DROPPING INTO THE UPPER 40S.

NEAR TO SLIGHTLY ABOVE SEASONABLE TEMPS AND MORE HUMID CONDITIONS
LIKELY FOR NEXT WEEK AS SURFACE HIGH PRESSURE SETTLES SOUTH OF THE
REGION AND A SERIES OF WEAK FRONTS AFFECT THE AREA. PREDICTABILITY
OF SHORTWAVES AND ASSOCIATED FRONTS IS LOW THIS FAR OUT...BUT
POTENTIAL EXISTS FOR A FEW PERIODS OF SHOWERS AND THUNDERSTORMS FROM
MONDAY AFTERNOON ONWARDS. MOST ACTIVITY WILL LIKELY BE DIURNAL AND
SCATTERED ACROSS THE INTERIOR...BUT PATTERN COULD SUPPORT AN
ORGANIZED CONVECTIVE COMPLEX AT ANY TIME DURING THE MID TO LATE WEEK
PERIOD.

&&

.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
MAINLY VFR CONDITIONS OUTSIDE OF -SHRA ACTIVITY AS A COLD FRONT
APPROACHES THE AREA. MVFR POSSIBLE IN -SHRA.

ACTIVITY OVER THE AREA HAS WEAKENED AND THERE SHOULD BE A BIT OF A
BREAK BEFORE THE NEXT POTENTIAL SET OF SHRA/TSTMS AFFECTS THE
TERMINALS. WATCHING A CLUSTER OF STORMS OVER EASTERN PA AT 20Z
TRACKING ESE. STORM MOVEMENT IS SLOW AND IS CURRENTLY NOT EXPECTED
TO IMPACT THE AIRFIELD UNTIL AROUND 00Z. IT MAY WEAKEN AS IT
APPROACHES DUE TO THE LOSS OF HEATING...BUT WILL WATCH OVER THE
NEXT HOUR AND AMEND IF NEEDED. OTHERWISE...HIGH RES MODELS HAVE
BEEN INDICATING THAT THE LINE OF SHOWERS/TSTMS ASSOCIATED WITH THE
COLD FRONT BACK OVER CENTRAL NY AND PA IS EXPECTED TO WEAKEN
BEFORE REACHING THE TERMINALS. KSWF MAY SEE A SHOWER FROM IT...BUT
EVERYONE ELSE SHOULD REMAIN DRY.

FRONT WILL PUSH ACROSS THE REGION TONIGHT INTO EARLY FRI
MORNING...02Z-05Z AT KSWF TO 06Z-09Z AT KISP/KGON. THIS WILL ALLOW
WINDS TO SHIFT TO 260-280 TRUE 00Z-02Z TONIGHT...THEN TO 320-350
TRUE LATE TONIGHT INTO FRIDAY MORNING. AN ISOLATED WIND GUST UP TO
20 KT IS POSSIBLE DURING THE DAY ON FRIDAY.


   NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH THE EVE PUSH.

KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH THE EVE PUSH.

KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH THE EVE PUSH.

KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH 02Z.

KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH 02Z.

KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH 02Z.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRI-MON...VFR.
.TUE...SUB VFR POSSIBLE IN SHRA/TSRA WITH COLD FRONT.

&&

.MARINE...
TSTM THREAT HAS WANED FOR NOW...BUT WATERS INVOF NYC MAY SEE
ADDITIONAL ACTIVITY AHEAD OF AN APPROACHING COLD FRONT THIS
EVENING. OTHERWISE...POST-FRONTAL FLOW LATE TONIGHT INTO FRI COULD
GUST TO 20 KT AT TIMES ESPECIALLY NEAR SHORE...BUT SCA CONDS NOT
EXPECTED...WITH OCEAN SEAS NO HIGHER THAN 3 FT. QUIET CONDITIONS
SHOULD LAST INTO EARLY NEXT WEEK.

&&

.HYDROLOGY...
SCT SHOWERS AND THUNDERSTORMS MAINLY NORTH/WEST OF NYC THIS
EVENING COULD STILL PRODUCE LOCALIZED HEAVY RAIN AND MINOR
FLOODING.

HEAVY RAIN POTENTIAL MID TO LATE NEXT WEEK WILL BE TIED TO TSTM
ACTIVITY...WHICH HAS LOW PREDICTABILITY IN TIMING AND LOCATION AT
THIS TIME.

&&

.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD...THE NEW
YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 HAS BEEN
TEMPORARILY TAKEN OUT OF SERVICE WHILE A SOLUTION IS
BEING FORMULATED.

DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS RADIO PUBLIC WARNING
SYSTEM DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...GOODMAN/NV
NEAR TERM...JMC/GOODMAN
SHORT TERM...GOODMAN
LONG TERM...NV
AVIATION...JP
MARINE...GOODMAN/NV
HYDROLOGY...GOODMAN/NV
EQUIPMENT...







AREA FORECAST DISCUSSION

NWS NEW YORK NY

 509 PM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT WILL APPROACH THIS EVENING AND MOVE ACROSS OVERNIGHT.
HIGH PRESSURE WILL THEN BUILD IN FROM FRIDAY THROUGH SUNDAY...AND
SETTLE TO THE SOUTH ON MONDAY. A SERIES OF FRONTS WILL MOVE ACROSS
THROUGH THE MID TO LATE PORTION OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID LEVEL TROUGH OVER THE MID ATLC REGION STILL SPARKING SHOWERS
AND ISOLD TSTMS. STRONGEST ACTIVITY HAS ORGANIZED WELL TO THE
SOUTH...SO AREA OF MAINLY LIGHT PRECIP SHOULD CONTINUE E FROM NYC
METRO INTO LONG ISLAND AND COASTAL CT INTO EARLY THIS EVENING.

WATCHING ENHANCED CU FIELD EXTENDING FROM THE CATSKILLS TO THE
POCONOS FOR ADDITIONAL SCT DEVELOPMENT THAT COULD IMPACT AREAS
MAINLY NORTH/WEST OF NYC INTO THIS EVENING. MLCAPE INCREASING TO
1000-1500 J/KG NORTH/WEST OF NYC BUT SHEAR IS WEAK...SO MAIN MODE
WILL BE PULSE CELLS...THE STRONGER IF WHICH ARE CAPABLE OF HEAVY
RAIN AND GUSTY WINDS.

CONVECTION WITH ACTUAL COLD FRONT STILL OVER WRN PA/NY IS FCST BY
17Z HRRR TO WEAKEN VIA NIGHTTIME COOLING/STABILIZATION. LEFT IN
SLIGHT CHANCE POP IN SOME AREAS AFTER MIDNIGHT IN CASE ANY OF IT
SHOULD SURVIVE THIS FAR EAST. MOCLDY SKIES SHOULD CLEAR LATE
AFTER FROPA...WITH LOWS MAINLY 65-70.

A MODERATE RIP CURRENT RISK CONTINUES FROM SMITH POINT BEACH EAST
TO MONTAUK INTO THIS EVENING.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
DRIER AIR WILL MOVE IN ON A N-NW BREEZE...WITH DEWPOINTS DROPPING
INTO THE 50S. HIGHS ON FRIDAY WILL REACH THE MID/UPPER 80S.
MOCLEAR SKIES AND DIMINISHING WINDS AS THE HIGH BUILDS OHD WILL
LEAD TO A COOLER NIGHT...WITH LOWER FRI NIGHT FROM THE MID 50S TO
MID 60S. EXCEPTION TO THIS MAY BE ACROSS LONG ISLAND...WHERE NWP
GUIDANCE HAS ADVERTISED MORE IN THE WAY OF CLOUDS AND POSSIBLE A
FEW LATE NIGHT SHOWERS AS AN UPPER LEVEL VORT MAX MOVES ACROSS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
MAIN CONTROLLING FEATURE ACROSS THE US WILL BE THE LARGE UPPER RIDGE
ACROSS THE CENTRAL US...WHICH WILL BUILD SLIGHTLY EASTWARD TOWARDS
THE EASTERN US BY THE END OF THE WEEKEND. THIS WILL PLACE THE REGION
ON THE NE EDGE OF UPPER RIDGING AND IN THE PATH OF A QUICK UPPER
FLOW FOR MUCH OF NEXT WEEK...WITH A SERIES OF WEAK DISTURBANCE
PASSING THROUGH THE NE.

AT THE SURFACE CANADIAN HIGH PRESSURE WILL BUILD INTO AND THEN SLIDE
ACROSS THE REGION THROUGH THE WEEKEND...PROVIDING FAIR AND
SEASONABLY WARM DAYTIME TEMPS. OVERNIGHT LOWS WILL LIKELY BE A BIT
CHILLY ACROSS FAR OUTLYING AREAS SAT NIGHT WITH GOOD RADIATIONAL
COOLING CONDS...PERHAPS DROPPING INTO THE UPPER 40S.

NEAR TO SLIGHTLY ABOVE SEASONABLE TEMPS AND MORE HUMID CONDITIONS
LIKELY FOR NEXT WEEK AS SURFACE HIGH PRESSURE SETTLES SOUTH OF THE
REGION AND A SERIES OF WEAK FRONTS AFFECT THE AREA. PREDICTABILITY
OF SHORTWAVES AND ASSOCIATED FRONTS IS LOW THIS FAR OUT...BUT
POTENTIAL EXISTS FOR A FEW PERIODS OF SHOWERS AND THUNDERSTORMS FROM
MONDAY AFTERNOON ONWARDS. MOST ACTIVITY WILL LIKELY BE DIURNAL AND
SCATTERED ACROSS THE INTERIOR...BUT PATTERN COULD SUPPORT AN
ORGANIZED CONVECTIVE COMPLEX AT ANY TIME DURING THE MID TO LATE WEEK
PERIOD.

&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
MAINLY VFR CONDITIONS OUTSIDE OF -SHRA ACTIVITY AS A COLD FRONT
APPROACHES THE AREA. MVFR POSSIBLE IN -SHRA.

ACTIVITY OVER THE AREA HAS WEAKENED AND THERE SHOULD BE A BIT OF A
BREAK BEFORE THE NEXT POTENTIAL SET OF SHRA/TSTMS AFFECTS THE
TERMINALS. WATCHING A CLUSTER OF STORMS OVER EASTERN PA AT 20Z
TRACKING ESE. STORM MOVEMENT IS SLOW AND IS CURRENTLY NOT EXPECTED
TO IMPACT THE AIRFIELD UNTIL AROUND 00Z. IT MAY WEAKEN AS IT
APPROACHES DUE TO THE LOSS OF HEATING...BUT WILL WATCH OVER THE
NEXT HOUR AND AMEND IF NEEDED. OTHERWISE...HIGH RES MODELS HAVE
BEEN INDICATING THAT THE LINE OF SHOWERS/TSTMS ASSOCIATED WITH THE
COLD FRONT BACK OVER CENTRAL NY AND PA IS EXPECTED TO WEAKEN
BEFORE REACHING THE TERMINALS. KSWF MAY SEE A SHOWER FROM IT...BUT
EVERYONE ELSE SHOULD REMAIN DRY.

FRONT WILL PUSH ACROSS THE REGION TONIGHT INTO EARLY FRI
MORNING...02Z-05Z AT KSWF TO 06Z-09Z AT KISP/KGON. THIS WILL ALLOW
WINDS TO SHIFT TO 260-280 TRUE 00Z-02Z TONIGHT...THEN TO 320-350
TRUE LATE TONIGHT INTO FRIDAY MORNING. AN ISOLATED WIND GUST UP TO
20 KT IS POSSIBLE DURING THE DAY ON FRIDAY.


   NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH THE EVE PUSH.

KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH THE EVE PUSH.

KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH THE EVE PUSH.

KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH 02Z.

KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH 02Z.

KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHRA/TSRA
THROUGH 02Z.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
.FRI-MON...VFR.
.TUE...SUB VFR POSSIBLE IN SHRA/TSRA WITH COLD FRONT.

&&

.MARINE...
TSTM THREAT HAS WANED FOR NOW...BUT WATERS INVOF NYC MAY SEE
ADDITIONAL ACTIVITY AHEAD OF AN APPROACHING COLD FRONT THIS
EVENING. OTHERWISE...POST-FRONTAL FLOW LATE TONIGHT INTO FRI COULD
GUST TO 20 KT AT TIMES ESPECIALLY NEAR SHORE...BUT SCA CONDS NOT
EXPECTED...WITH OCEAN SEAS NO HIGHER THAN 3 FT. QUIET CONDITIONS
SHOULD LAST INTO EARLY NEXT WEEK.

&&

.HYDROLOGY...
SCT SHOWERS AND THUNDERSTORMS MAINLY NORTH/WEST OF NYC THIS
EVENING COULD STILL PRODUCE LOCALIZED HEAVY RAIN AND MINOR
FLOODING.

HEAVY RAIN POTENTIAL MID TO LATE NEXT WEEK WILL BE TIED TO TSTM
ACTIVITY...WHICH HAS LOW PREDICTABILITY IN TIMING AND LOCATION AT
THIS TIME.

&&

.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD...THE NEW
YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 HAS BEEN
TEMPORARILY TAKEN OUT OF SERVICE WHILE A SOLUTION IS
BEING FORMULATED.

DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS RADIO PUBLIC WARNING
SYSTEM DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...GOODMAN/NV
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...NV
AVIATION...JP
MARINE...GOODMAN/NV
HYDROLOGY...GOODMAN/NV
EQUIPMENT...








AREA FORECAST DISCUSSION

NWS NEW YORK NY

 356 PM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT WILL APPROACH THIS EVENING AND MOVE ACROSS OVERNIGHT.
HIGH PRESSURE WILL THEN BUILD IN FROM FRIDAY THROUGH SUNDAY...AND
SETTLE TO THE SOUTH ON MONDAY. A SERIES OF FRONTS WILL MOVE ACROSS
THROUGH THE MID TO LATE PORTION OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
MID LEVEL TROUGH OVER THE MID ATLC REGION STILL SPARKING SHOWERS
AND ISOLD TSTMS. STRONGEST ACTIVITY HAS ORGANIZED WELL TO THE
SOUTH...SO AREA OF MAINLY LIGHT PRECIP SHOULD CONTINUE E FROM NYC
METRO INTO LONG ISLAND AND COASTAL CT INTO EARLY THIS EVENING.

WATCHING ENHANCED CU FIELD EXTENDING FROM THE CATSKILLS TO THE
POCONOS FOR ADDITIONAL SCT DEVELOPMENT THAT COULD IMPACT AREAS
MAINLY NORTH/WEST OF NYC INTO THIS EVENING. MLCAPE INCREASING TO
1000-1500 J/KG NORTH/WEST OF NYC BUT SHEAR IS WEAK...SO MAIN MODE
WILL BE PULSE CELLS...THE STRONGER IF WHICH ARE CAPABLE OF HEAVY
RAIN AND GUSTY WINDS.

CONVECTION WITH ACTUAL COLD FRONT STILL OVER WRN PA/NY IS FCST BY
17Z HRRR TO WEAKEN VIA NIGHTTIME COOLING/STABILIZATION. LEFT IN
SLIGHT CHANCE POP IN SOME AREAS AFTER MIDNIGHT IN CASE ANY OF IT
SHOULD SURVIVE THIS FAR EAST. MOCLDY SKIES SHOULD CLEAR LATE
AFTER FROPA...WITH LOWS MAINLY 65-70.

A MODERATE RIP CURRENT RISK CONTINUES FROM SMITH POINT BEACH EAST
TO MONTAUK INTO THIS EVENING.

&&

.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
DRIER AIR WILL MOVE IN ON A N-NW BREEZE...WITH DEWPOINTS DROPPING
INTO THE 50S. HIGHS ON FRIDAY WILL REACH THE MID/UPPER 80S.
MOCLEAR SKIES AND DIMINISHING WINDS AS THE HIGH BUILDS OHD WILL
LEAD TO A COOLER NIGHT...WITH LOWER FRI NIGHT FROM THE MID 50S TO
MID 60S. EXCEPTION TO THIS MAY BE ACROSS LONG ISLAND...WHERE NWP
GUIDANCE HAS ADVERTISED MORE IN THE WAY OF CLOUDS AND POSSIBLE A
FEW LATE NIGHT SHOWERS AS AN UPPER LEVEL VORT MAX MOVES ACROSS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
MAIN CONTROLLING FEATURE ACROSS THE US WILL BE THE LARGE UPPER RIDGE
ACROSS THE CENTRAL US...WHICH WILL BUILD SLIGHTLY EASTWARD TOWARDS
THE EASTERN US BY THE END OF THE WEEKEND. THIS WILL PLACE THE REGION
ON THE NE EDGE OF UPPER RIDGING AND IN THE PATH OF A QUICK UPPER
FLOW FOR MUCH OF NEXT WEEK...WITH A SERIES OF WEAK DISTURBANCE
PASSING THROUGH THE NE.

AT THE SURFACE CANADIAN HIGH PRESSURE WILL BUILD INTO AND THEN SLIDE
ACROSS THE REGION THROUGH THE WEEKEND...PROVIDING FAIR AND
SEASONABLY WARM DAYTIME TEMPS. OVERNIGHT LOWS WILL LIKELY BE A BIT
CHILLY ACROSS FAR OUTLYING AREAS SAT NIGHT WITH GOOD RADIATIONAL
COOLING CONDS...PERHAPS DROPPING INTO THE UPPER 40S.

NEAR TO SLIGHTLY ABOVE SEASONABLE TEMPS AND MORE HUMID CONDITIONS
LIKELY FOR NEXT WEEK AS SURFACE HIGH PRESSURE SETTLES SOUTH OF THE
REGION AND A SERIES OF WEAK FRONTS AFFECT THE AREA. PREDICTABILITY
OF SHORTWAVES AND ASSOCIATED FRONTS IS LOW THIS FAR OUT...BUT
POTENTIAL EXISTS FOR A FEW PERIODS OF SHOWERS AND THUNDERSTORMS FROM
MONDAY AFTERNOON ONWARDS. MOST ACTIVITY WILL LIKELY BE DIURNAL AND
SCATTERED ACROSS THE INTERIOR...BUT PATTERN COULD SUPPORT AN
ORGANIZED CONVECTIVE COMPLEX AT ANY TIME DURING THE MID TO LATE WEEK
PERIOD.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AREA OF SHRA/TSRA OVER CENTRAL NJ SHOULD PASS SOUTH OF MOST OF THE
CITY TERMINALS. KJFK COULD GET CLIPPED BY THESE STORMS...SO PUT IN
A TEMPO GROUP FOR -TSRA. OTHERWISE...-SHRA ACTIVITY OUT AHEAD OF
AN APPROACHING COLD FRONT. CONDITIONS FOR THE MOST PART SHOULD BE
VFR...BUT COULD LOWER TO MVFR OR LOWER IN HEAVIER SHRA/TSRA ACTIVITY.

FRONT WILL PUSH ACROSS THE REGION TONIGHT INTO EARLY FRI MORNING
     02Z-05Z AT KSWF TO 06Z-09Z AT KISP/KGON.


   NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.THU NIGHT...PSBL MVFR TO LOCALLY IFR WITH ANY RESIDUAL
SHOWERS/TSTMS. COLD FROPA.
.FRI-MON...VFR.

&&

.MARINE...
TSTM THREAT HAS WANED FOR NOW...BUT WATERS INVOF NYC MAY SEE
ADDITIONAL ACTIVITY AHEAD OF AN APPROACHING COLD FRONT THIS
EVENING. OTHERWISE...POST-FRONTAL FLOW LATE TONIGHT INTO FRI COULD
GUST TO 20 KT AT TIMES ESPECIALLY NEAR SHORE...BUT SCA CONDS NOT
EXPECTED...WITH OCEAN SEAS NO HIGHER THAN 3 FT. QUIET CONDITIONS
SHOULD LAST INTO EARLY NEXT WEEK.


&&

.HYDROLOGY...
SCT SHOWERS AND THUNDERSTORMS MAINLY NORTH/WEST OF NYC THIS
EVENING COULD STILL PRODUCE LOCALIZED HEAVY RAIN AND MINOR
FLOODING.

HEAVY RAIN POTENTIAL MID TO LATE NEXT WEEK WILL BE TIED TO TSTM
ACTIVITY...WHICH HAS LOW PREDICTABILITY IN TIMING AND LOCATION AT
THIS TIME.

&&

.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD...THE NEW
YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 HAS BEEN
TEMPORARILY TAKEN OUT OF SERVICE WHILE A SOLUTION IS
BEING FORMULATED.

DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS RADIO PUBLIC WARNING
SYSTEM DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...GOODMAN/NV
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...NV
AVIATION...JP
MARINE...GOODMAN/NV
HYDROLOGY...GOODMAN/NV
EQUIPMENT...GOODMAN






AREA FORECAST DISCUSSION

NWS NEW YORK NY

 153 PM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT APPROACHES FROM THE NORTHWEST THIS AFTERNOON...THEN MOVES
ACROSS THE REGION TONIGHT. HIGH PRESSURE BUILDS INTO THE TRI-
STATE BEHIND THE FRONT...THEN SETTLES TO THE SOUTH LATE THIS WEEKEND. A
SERIES OF TROUGHS WILL TRACK ACROSS THE REGION THROUGH THE MIDDLE
PORTION OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PASSING 700-500 HPA SHORTWAVE COUPLED WITH PRE-FRONTAL SHRA
RESPONSIBLE FOR ONGOING SHRA/TSTM ACROSS THE TRI-STATE. HAVE
INCREASED POPS TO CATEGORICAL OVER NEXT FEW HOURS OVER MAINLY LONG
ISLAND BASED ON LATEST RADAR TRENDS.

STILL HAVE ANOTHER SHORTWAVE TO COME...SO HAVE CONTINUED WITH SCT
SHRA/TSTMS FOR THIS AFTERNOON. CAPES ON 12Z SOUNDINGS RANGED FROM
1000-2000 J/KG...BUT WITH FREEZING LEVELS OVER 14000 FT AND -20C
LEVEL AROUND 25000 FT IT IS A VERY WARM PROFILE - SO LOCALLY HEAVY
RAIN IS MAIN THREAT. SEE HYDROLOGY SECTION FOR DETAILS. GIVEN CAPE
CANNOT COMPLETELY RULE OUT LOCALLY STRONG TO SEVERE STORM -
ESPECIALLY OVER WESTERN ZONES IF THERE IS SOME SUN THIS AFTERNOON.

LATEST SATELLITE TRENDS MAKE IDEA OF EXTENSIVE BREAKS IN THE SUN
DOUBTFUL...AND BASED ON HOURLY TEMPERATURES CURRENTLY RUNNING
QUITE A BIT COOLER THAN FORECAST HAVE LOWERED HIGHS A FEW DEGREES
- CONSISTENT WITH A BLEND OF HRRR AND NAM 2-METER TEMPERATURES
WITH 12Z MET/6Z MAV AND LAV GUIDANCE.

THERE IS A MODERATE RISK OF RIP CURRENTS FROM SMITHS POINT BEACH
EAST TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
COLD FRONT MOVES ACROSS THE REGION FROM WEST TO EAST THROUGH
MIDNIGHT TONIGHT...AND THEN H5 TROUGH MOVES ACROSS THE REGION ON
FRIDAY. SHOWERS/TSTMS TAPER OFF FROM WEST TO EAST BY FRIDAY
MORNING...AND THEN DRYER AIR FILTERS INTO THE REGION AS HIGH PRES
BEGINS TO BUILD EAST AND SFC DEW POINTS DROP INTO THE MID/UPPER
50S.

LOWS TONIGHT WILL GENERALLY DROP INTO THE LOWER 70S IN/AROUND
NYC...AND INTO THE 60S ELSEWHERE. HIGHS ON FRIDAY WILL REACH THE
MID/UPPER 80S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS TIME FRAME WILL FEATURE EXITING TROUGH OVER THE
NORTHEAST...WITH LARGE RIDGE BUILDING IN ACROSS THE MIDDLE OF THE
COUNTRY. BY EARLY NEXT WEEK...HEIGHTS LOWER ACROSS THE
NORTHEAST...WITH SUBTLE MODEL DIFFERENCES NOTED IN THE MEDIUM TO
LONG RANGE WITH REGARD TO EMBEDDED SHORTWAVES AND ASSOCIATED SFC
TROUGHS.

WILL THUS NOT STRAY TOO FAR FROM FORECAST...AND A DRY WEEKEND WILL
GIVE WAY TO UNSETTLED WEATHER EARLY TO MID WEEK NEXT WEEK. TIMING
OF ANY SCATTERED CONVECTION WILL BE EXTREMELY DIFFICULT TO DO THIS
FAR OUT.

OVERALL...NEAR NORMAL TEMPERATURES ARE ANTICIPATED THROUGH THIS
TIME FRAME FOR OUR LOCAL AREA...WITH THE HEAT REMAINING ACROSS THE
MIDDLE PORTION OF THE COUNTRY UNDERNEATH THE RIDGE.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AREA OF SHRA/TSRA OVER CENTRAL NJ SHOULD PASS SOUTH OF MOST OF THE
CITY TERMINALS. KFJK COULD GET CLIPPED BY THESE STORMS...SO PUT IN
A TEMPO GROUP FOR -TSRA. OTHERWISE...-SHRA ACTIVITY OUT AHEAD OF
AN APPROACHING COLD FRONT. CONDITIONS FOR THE MOST PART SHOULD BE
VFR...BUT COULD LOWER TO MVFR OR LOWER IN HEAVIER SHRA/TSRA ACTIVITY.

FRONT WILL PUSH ACROSS THE REGION TONIGHT INTO EARLY FRI MORNING
...02Z-05Z AT KSWF TO 06Z-09Z AT KISP/KGON.


   NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.THU NIGHT...PSBL MVFR TO LOCALLY IFR WITH ANY RESIDUAL
SHOWERS/TSTMS. COLD FROPA.
.FRI-MON...VFR.

&&

.MARINE...
THUNDERSTORMS LIKELY ACROSS LONG ISLAND SOUND AND POSSIBLE ACROSS
THE REMAINDER OF THE WATERS THROUGH THIS EVENING.

AN APPROACHING COLD FRONT THIS AFTERNOON....THAT CROSSES THE WATERS
TONIGHT COULD BRING SUSTAINED WINDS UP TO 15 KT GUSTS UP TO 20 KT
ON THE COASTAL OCEAN WATERS THROUGH TONIGHT. OTHERWISE...WINDS ARE
EXPECTED TO REMAIN 10 KT OR LESS OVER AREA WATERS THROUGH FRIDAY.
WITH THESE RELATIVELY LIGHT WINDS...SEAS ON THE COASTAL OCEAN
WATERS SHOULD REMAIN AT 3 FT OR LESS AND ON THE REMAINDER OF THE
WATERS 1 FT OR LESS THROUGH FRIDAY NIGHT AS WELL.

SUB SCA CONDITIONS ANTICIPATED FROM FRIDAY NIGHT INTO EARLY NEXT
WEEK.

&&

.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY THROUGH
TONIGHT. WITH PRECIPITABLE WATER VALUES OF 1 1/2 TO 2
INCHES...ANY THUNDERSTORMS THAT DO DEVELOP COULD PRODUCE LOCALLY
HEAVY RAIN...AND POSSIBLY MINOR FLOODING OF URBAN AND/OR POOR
DRAINAGE AREAS AS A RESULT. ISOLATED FLASH FLOODING...WHILE HIGHLY
UNLIKELY CANNOT BE COMPLETELY RULED OUT IF TRAINING OCCURS.

MAINLY DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND. LOCAL HEAVY
RAIN WILL BE POSSIBLE WITH ANY SHOWERS AND THUNDERSTORMS NEXT
WEEK.

&&

.EQUIPMENT...
THE NOAA ALL HAZARDS WEATHER RADIO TRANSMITTER IN NEW YORK CITY
HAS BEEN REMOVED FROM SERVICE. TECHNICIANS CONTINUE TO WORK ON THE
SITUATION AND A TIME OF RETURN TO SERVICE IS UNKNOWN.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MPS/PW
NEAR TERM...MPS/PW
SHORT TERM...MPS
LONG TERM...PW
AVIATION...JP
MARINE...MPS/PW
HYDROLOGY...MPS/PW
EQUIPMENT...







AREA FORECAST DISCUSSION

NWS NEW YORK NY

 1114 AM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT APPROACHES FROM THE NORTHWEST THIS AFTERNOON...THEN MOVES
ACROSS THE REGION TONIGHT. HIGH PRESSURE BUILDS INTO THE TRI-
STATE BEHIND THE FRONT...THEN SETTLES TO THE SOUTH LATE THIS WEEKEND. A
SERIES OF TROUGHS WILL TRACK ACROSS THE REGION THROUGH THE MIDDLE
PORTION OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PASSING 700-500 HPA SHORTWAVE COUPLED WITH PRE-FRONTAL SHRA
RESPONSIBLE FOR ONGOING SHRA/TSTM ACROSS THE TRI-STATE. HAVE
INCREASED POPS TO CATEGORICAL OVER NEXT FEW HOURS OVER MAINLY LONG
ISLAND BASED ON LATEST RADAR TRENDS.

STILL HAVE ANOTHER SHORTWAVE TO COME...SO HAVE CONTINUED WITH SCT
SHRA/TSTMS FOR THIS AFTERNOON. CAPES ON 12Z SOUNDINGS RANGED FROM
1000-2000 J/KG...BUT WITH FREEZING LEVELS OVER 14000 FT AND -20C
LEVEL AROUND 25000 FT IT IS A VERY WARM PROFILE - SO LOCALLY HEAVY
RAIN IS MAIN THREAT. SEE HYDROLOGY SECTION FOR DETAILS. GIVEN CAPE
CANNOT COMPLETELY RULE OUT LOCALLY STRONG TO SEVERE STORM -
ESPECIALLY OVER WESTERN ZONES IF THERE IS SOME SUN THIS AFTERNOON.

LATEST SATELLITE TRENDS MAKE IDEA OF EXTENSIVE BREAKS IN THE SUN
DOUBTFUL...AND BASED ON HOURLY TEMPERATURES CURRENTLY RUNNING
QUITE A BIT COOLER THAN FORECAST HAVE LOWERED HIGHS A FEW DEGREES
- CONSISTENT WITH A BLEND OF HRRR AND NAM 2-METER TEMPERATURES
WITH 12Z MET/6Z MAV AND LAV GUIDANCE.

THERE IS A MODERATE RISK OF RIP CURRENTS FROM SMITHS POINT BEACH
EAST TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
COLD FRONT MOVES ACROSS THE REGION FROM WEST TO EAST THROUGH
MIDNIGHT TONIGHT...AND THEN H5 TROUGH MOVES ACROSS THE REGION ON
FRIDAY. SHOWERS/TSTMS TAPER OFF FROM WEST TO EAST BY FRIDAY
MORNING...AND THEN DRYER AIR FILTERS INTO THE REGION AS HIGH PRES
BEGINS TO BUILD EAST AND SFC DEW POINTS DROP INTO THE MID/UPPER
50S.

LOWS TONIGHT WILL GENERALLY DROP INTO THE LOWER 70S IN/AROUND
NYC...AND INTO THE 60S ELSEWHERE. HIGHS ON FRIDAY WILL REACH THE
MID/UPPER 80S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THIS TIME FRAME WILL FEATURE EXITING TROUGH OVER THE
NORTHEAST...WITH LARGE RIDGE BUILDING IN ACROSS THE MIDDLE OF THE
COUNTRY. BY EARLY NEXT WEEK...HEIGHTS LOWER ACROSS THE
NORTHEAST...WITH SUBTLE MODEL DIFFERENCES NOTED IN THE MEDIUM TO
LONG RANGE WITH REGARD TO EMBEDDED SHORTWAVES AND ASSOCIATED SFC
TROUGHS.

WILL THUS NOT STRAY TOO FAR FROM FORECAST...AND A DRY WEEKEND WILL
GIVE WAY TO UNSETTLED WEATHER EARLY TO MID WEEK NEXT WEEK. TIMING
OF ANY SCATTERED CONVECTION WILL BE EXTREMELY DIFFICULT TO DO THIS
FAR OUT.

OVERALL...NEAR NORMAL TEMPERATURES ARE ANTICIPATED THROUGH THIS
TIME FRAME FOR OUR LOCAL AREA...WITH THE HEAT REMAINING ACROSS THE
MIDDLE PORTION OF THE COUNTRY UNDERNEATH THE RIDGE.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
FIRST ROUND OF SHRA/TSRA HAS MOVED EAST OF THE AREA. WATCHING AN
AREA OF SHRA/TSRA OVER NORTHERN NJ. RIGHT NOW THINKING THAT THIS
WILL MOVE JUST WEST OF KEWR AND KTEB...SO ADDED VCTS FOR THESE
TERMINAL BETWEEN 1530-1630Z. CCFP HAS HIGH CONFIDENCE OF SPARSE
COVERAGE OVER THE CITY TERMINALS AT 19Z...SO ADDED TEMPO GROUP FOR
-TSRA FROM 18-21Z TODAY.

A TROUGH OF LOW PRESSURE WILL REMAIN OVER THE AREA TODAY AS A
COLD FRONT APPROACHES FROM THE WEST. THE FRONT WILL PUSH ACROSS
THE REGION TONIGHT INTO EARLY FRI MORNING...02Z-05Z AT KSWF TO
06Z-09Z AT KISP/KGON.


   NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT:  HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KEWR FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KTEB FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR TIMING OF SHOWERS AND
ANY TSRA DEVELOPMENT TODAY.

OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY...
.THU NIGHT...PSBL MVFR TO LOCALLY IFR WITH ANY RESIDUAL
SHOWERS/TSTMS. COLD FROPA.
.FRI-MON...VFR.

&&

.MARINE...
THUNDERSTORMS LIKELY ACROSS LONG ISLAND SOUND AND POSSIBLE ACROSS
THE REMAINDER OF THE WATERS THROUGH THIS EVENING.

AN APPROACHING COLD FRONT THIS AFTERNOON....THAT CROSSES THE WATERS
TONIGHT COULD BRING SUSTAINED WINDS UP TO 15 KT GUSTS UP TO 20 KT
ON THE COASTAL OCEAN WATERS THROUGH TONIGHT. OTHERWISE...WINDS ARE
EXPECTED TO REMAIN 10 KT OR LESS OVER AREA WATERS THROUGH FRIDAY.
WITH THESE RELATIVELY LIGHT WINDS...SEAS ON THE COASTAL OCEAN
WATERS SHOULD REMAIN AT 3 FT OR LESS AND ON THE REMAINDER OF THE
WATERS 1 FT OR LESS THROUGH FRIDAY NIGHT AS WELL.

SUB SCA CONDITIONS ANTICIPATED FROM FRIDAY NIGHT INTO EARLY NEXT
WEEK.

&&

.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY THROUGH
TONIGHT. WITH PRECIPITABLE WATER VALUES OF 1 1/2 TO 2
INCHES...ANY THUNDERSTORMS THAT DO DEVELOP COULD PRODUCE LOCALLY
HEAVY RAIN...AND POSSIBLY MINOR FLOODING OF URBAN AND/OR POOR
DRAINAGE AREAS AS A RESULT. ISOLATED FLASH FLOODING...WHILE HIGHLY
UNLIKELY CANNOT BE COMPLETELY RULED OUT IF TRAINING OCCURS.

MAINLY DRY CONDITIONS ARE EXPECTED OVER THE WEEKEND. LOCAL HEAVY
RAIN WILL BE POSSIBLE WITH ANY SHOWERS AND THUNDERSTORMS NEXT
WEEK.

&&

.EQUIPMENT...
THE NOAA ALL HAZARDS WEATHER RADIO TRANSMITTER IN NEW YORK CITY
HAS BEEN REMOVED FROM SERVICE. TECHNICIANS CONTINUE TO WORK ON THE
SITUATION AND A TIME OF RETURN TO SERVICE IS UNKNOWN.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MPS/PW
NEAR TERM...MPS/PW
SHORT TERM...MPS
LONG TERM...PW
AVIATION...JP
MARINE...MPS/PW
HYDROLOGY...MPS/PW
EQUIPMENT...









AREA FORECAST DISCUSSION

NWS TAUNTON MA

 1012 AM EDT THU AUG 22 2013

.SYNOPSIS...
CONTINUED WARM AND MUGGY CONDITIONS AHEAD OF A SERIES OF WET
WEATHER DISTURBANCES TODAY INTO FRIDAY. SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED...CLEARING OUT BY AS LATE AS FRIDAY NIGHT.
THEREAFTER DRY AND NEAR SEASONABLE WEATHER WILL RETURN THIS
WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION. MORE HUMID
CONDITIONS AND PERIODS OF UNSETTLED WEATHER MOVES IN NEXT WEEK AS
A WARM FRONT MOVES INTO THE REGION.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

1015 AM UPDATE...
FOG OVER THE REGION CONTINUES TO LINGER AS SOUTHERLY FLOW
CONTINUES TO STREAM IN MOISTURE ALONG THE COASTS. OTHERWISE FOCUS
TURNS TO SCATTERED SHOWERS AND THUNDERSTORMS CURRENTLY OVER THE
NYC AND LONG ISLAND. THESE SHOWERS WILL SLOWLY MOVE ACROSS THE
SOUTHERN HALF OF THE REGION AS A GOOD AMOUNT OF DRY AIR IS IN
PLACE ACROSS THE NORTH. THIS IS INDICATED BY THE K INDEX AND 700MB
MOISTURE FIELDS. TRENDED THE NEAR TERM TOWARDS THE 12Z NAM AND
HRRR PARAMETERS AS THEY HAVE AN EXCELLENT HANDLE ON CURRENT RADAR
IMAGERY. BELIEVE PRECIP SHOULD BEGIN TO ENTER THE SOUTHERN
HARTFORD COUNTY WITHIN THE HOUR AND SLOWLY WILL MOVE TOWARDS THE
REGION BY THE AFTERNOON HOURS. EXPECT MAIN THREATS TO BE LIGHTNING
AND HEAVY RAINFALL AS PWAT VALUES ARE AROUND 1.5.

PREVIOUS DISCUSSION...

FOCUS WILL BE ON THE DEAMPLIFYING MID-LEVEL LOW PRESSURE TRACKING
EAST ACROSS THE DELMARVA OUT TO SEA. SQUEEZING UP AGAINST ATLANTIC
HIGH PRESSURE AND PUSHED BY A STRONGER SHORTWAVE AND TROUGH AXIS
APPROACHING FROM THE EASTERN GREAT LAKES WILL YIELD AMPLIFICATION
OF MID- TO UPPER-LEVEL TROPOSPHERIC WINDS PROMOTING GREATER
DIFFLUENCE ALOFT. IN RESPONSE...SHOULD SEE AN ENHANCEMENT OF
SOUTHERLY FLOW WITHIN THE LOW-LEVELS ADVECTING MORE MUGGY
CONDITIONS INTO SOUTHERN NEW ENGLAND AGAINST DRIER AIR /GUSTS UP
TO 20 MPH ALONG THE SOUTH COAST/. SUBSEQUENT MOISTENING TO THE
WET-BULB OF THE ATMOSPHERIC PROFILE SHOULD ALLOW THE BUILD UP OF
ELEVATED INSTABILITY.

FEEL ANY ACTIVITY TODAY WILL BE LOCALIZED MAINLY SOUTH AND WEST IN
REGIONS OF FAVORABLE LIFT ALOFT COLLOCATED WITH AREAS OF LOW-LEVEL
CONVERGENCE THAT CAPITALIZE ON THE GROWING INSTABILITY...ESPECIALLY
IF THE BOUNDARY LAYER HAS AN OPPORTUNITY TO DESTABILIZE. STILL
DIFFICULT TO PIN-POINT...BUT FEEL AREAS NORTH AND EAST MAY REMAIN
UNDER THE INFLUENCE OF DRIER AND SINKING AIR.

GREATER CONFIDENCE WITH THE LATEST HRRR AND 22.0Z NAM HIGHLIGHTING
SOME EARLY MORNING ACTIVITY COLLOCATED WITH THE NOSE OF A LOW-LEVEL
JET AXIS JUST ABOVE THE DECOUPLED BOUNDARY LAYER. ACTIVITY OCCURRING
ACROSS NORTHEAST PENNSYLVANIA SHOULD FOCUS EASTWARD WITH TIME. BUT
OTHERWISE...A MAJORITY OF THE FORECAST AREA MAY SIMPLY REMAIN PARTLY
CLOUDY AND DRY...ALLOWING HIGHS TO GET INTO THE MID- TO UPPER-80S...
WITH A FEW LOCATIONS AT OR ABOVE THE 90 DEGREE MARK FOR A SECOND DAY
IN A ROW.

CONSIDERING A WEAK SHEAR ENVIRONMENT WITH MODEST INSTABILITY ALONG
WITH NEAR-ZERO CORFIDI VECTORS AND A WEAK MEAN ATMOSPHERIC FLOW
AROUND 15 MPH...MAIN THREATS ASSOCIATED WITH ANY STORMS APPEAR TO
BE HEAVY RAIN AND POSSIBLE NUISANCE FLOODING /PWATS CONTINUE TO
RANGE AROUND 1.5 TO 1.75 INCHES/. COULD SEE SOME GUSTY WINDS
SHOULD THE BOUNDARY LAYER MIX-OUT WITH INVERTED-V PROFILES.

ACTIVITY ALONG THE UPSTREAM COLD FRONT WILL NOT PUSH INTO THE
FORECAST REGION UNTIL EVENING.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...

STRONGER SHORTWAVE AND TROUGH AXIS WITH ATTENDANT SURFACE COLD FRONT
WILL SWEEP THROUGH THE REGION REACHING SOUTHEAST MASSACHUSETTS BY
MORNING. ANTICIPATING SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF
THE COLD FRONT AIDED BY STRONG FRONTOGENETICAL LIFT. INITIALLY
PUSHING INTO WESTERN NEW ENGLAND BY EVENING...ACTIVITY LOOKS TO
DIMINISH EASTWARD TOWARDS BY MIDNIGHT INTO MORNING AS BETTER
DYNAMICS ALOFT LIFT NORTH AND EAST PARENT WITH THE MID-LEVEL LOW.

WITH A STABILIZING BOUNDARY LAYER PROFILE...FEEL ANY STORMS WILL BE
MAINLY ASSOCIATED WITH HEAVY RAIN. LESSER CONFIDENCE FOR NUISANCE
FLOODING AS THE BETTER PWAT ENVIRONMENT WILL BE WELL SOUTH AND EAST
OFFSHORE OF THE REGION. LOWS AROUND THE MID-60S.

FRIDAY...

SURFACE COLD FRONT SLOWS OFFSHORE...STALLING SOUTH OF SOUTHERN NEW
ENGLAND. CLOUDS AND SHOWERS WILL LINGER FOR THE FAR SOUTH-SOUTHEAST
PORTIONS OF THE FORECAST AREA. NORTHWEST FLOW PREVAILS PUSHING
COOLER AND DRIER AIR SOUTH WITHIN THE LOW- TO MID-LEVELS.

EXPECTING DEEP BOUNDARY LAYER MIXING UP TO H8 LENDING TO SCATTERED
TO BROKEN DIURNAL CUMULUS AND THE POSSIBILITY FOR SOME SPOTTY
SHOWERS CAPITALIZING ON THE LIFT OF MINOR ELEVATED INSTABILITY AHEAD
OF A REINFORCING SECONDARY COLD FRONT. WILL INSERT SLIGHT CHANCE
POPS FOR A MAJORITY OF THE FORECAST REGION FOR THE MIDDAY INTO
AFTERNOON PERIOD. WILL ALSO SEE THE MIX-DOWN OF DRIER AIR AND FASTER
MOMENTUM. WIND GUSTS AROUND 15 MPH EXPECTED WITH HIGHS AROUND THE
LOW-80S...COOLER ALONG THE SHORES AND HIGHER ELEVATIONS.

FRIDAY NIGHT...

REINFORCING COLD FRONT PUSHES WELL OFFSHORE PARENT WITH ANOTHER MID-
LEVEL TROUGH AXIS SWEEPING ACROSS NEW ENGLAND. WINDS BACK MORE
NORTHERLY CONTINUALLY ADVECTING MORE COOLER AND DRIER AIR SOUTHWARD
OUT OF CANADA. LOOKING AT A POTENTIALLY CHILLY NIGHT SHOULD
CONDITIONS REMAIN MOSTLY CLEAR. LOWS AROUND THE MID-50S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...

* DRY AND COOLER SAT...THEN WARMER SUNDAY
* BECOMING MORE HUMID NEXT WEEK WITH UNSETTLED WEATHER POSSIBLE FROM
  TIME TO TIME.

OVERVIEW...
GUIDANCE IN GOOD AGREEMENT ON OVERALL PATTERN DURING THE EXTENDED
PERIOD. MID LEVEL TROF WHICH WILL BRING COOLER WEATHER TO START THE
WEEKEND WILL BE EXITING THE REGION BY SUNDAY. MODELS AGREE ON AN
ANOMALOUS AND EXPANSIVE MID LEVEL RIDGE BUILDING ACROSS THE CENTRAL
CONUS DURING MUCH OF THE PERIOD WITH SNE REMAINING ON THE SOUTHERN
EDGE OF THE POLAR JET WITH MAINLY NW FLOW ALOFT.  THIS WILL KEEP THE
SIGNIFICANT HEAT WEST OF SNE AND ALSO MAKE US SUSCEPTIBLE TO
OCCASIONAL IMPULSES IN NW FLOW BEGINNING NEXT WEEK. THE TIMING AND
AMPLITUDE OF INDIVIDUAL SHORTWAVES WILL DETERMINE THE COVERAGE AND
INTENSITY OF SHOWERS AND THUNDERSTORMS...BUT THE THREAT WILL EXIST
SOMETIME FROM LATE MON INTO WED.

SATURDAY AND SUNDAY...
STRONG HIGH PRES BUILDS ACROSS SNE GRADUALLY SHIFTING TO THE S ON
SUNDAY.  FOR SAT...NEARBY MID LEVEL TROF AND COLD POOL ACTING ON LOW
LEVEL MOISTURE WILL LIKELY BRING AT LEAST SCT-BKN CU BUT THE
MOISTURE IS SHALLOW SO DRY WEATHER EXPECTED.  LESS CU ON SUNDAY AS
MID LEVEL TEMPS WARM. TEMPS WILL BE A FEW DEGREES BELOW NORMAL
SAT...MOSTLY IN THE MID/UPPER 70S THEN WARMING INTO UPPER 70S AND
LOWER 80S SUNDAY IN RESPONSE TO INCREASING MID LEVEL TEMPS.

MONDAY...
SOME DIFFERENCES BETWEEN GFS AND ECMWF BEGIN TO SHOW UP REGARDING
THE EASTWARD EXTENT OF THE WARM FRONT. GFS APPEARS TO MOVE THE WARM
FRONT THROUGH TOO QUICKLY. PREFER THE ECMWF KEEPING THE FRONT TO THE
WEST GIVEN THE NW FLOW ALOFT. MOST OF THE REGION SHOULD REMAIN DRY
ALTHOUGH CANT RULE OUT A FEW SHOWERS OR A THUNDERSTORM ACROSS W
ZONES LATE IN THE DAY AS MOISTURE INCREASES FROM THE WEST.

MONDAY NIGHT INTO WEDNESDAY...
IT APPEARS FRONTAL BOUNDARY MAY GET HUNG UP NEAR SNE DURING THIS
PERIOD. THIS WILL BRING THE THREAT OF SHOWERS AND THUNDERSTORMS FROM
TIME TO TIME BUT WE HAVE LOW CONFIDENCE IN TIMING AS THERE ARE
DIFFERENCES IN THE MODELS. HUMIDITY WILL BE INCREASING ALTHOUGH THE
HEAT WILL REMAIN TO THE WEST WITH TEMPS MOSTLY NEAR SEASONABLE
NORMALS.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

OVERVIEW /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.

AREAS OF MVFR/IFR FOG AND STRATUS WILL BURN OFF BY MID
MORNING. SHRA/TSRA WILL BE ON THE INCREASE FROM THE SOUTH AND
WEST BY LATE MORNING INTO THE AFTERNOON HOURS. MENTIONED VCSH FOR
NOW WITH OVERWHELMING UNCERTAINTY ON THE EVOLUTION AND POTENTIAL
IMPACTS OF SHRA/TSRA. SOUTHWEST WINDS PREVAILING WITH GUSTS UP TO
AROUND 20 KTS.

ACTIVITY CLEARS UP INTO FRIDAY MORNING WITH A COLD FRONT SWEEPING
ACROSS THE TERMINALS...WINDS BACKING WEST-NORTHWEST. MAY SEE A
SPOT SHRA/TSRA DURING THE DAY FRIDAY...BUT A REINFORCING COLD
FRONT WITH NORTH-NORTHWEST FLOW TO THE REAR SHOULD PUSH ALL
REMAINING ACTIVITY OFFSHORE.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. NO EXPECTATION FOR A SEA-
BREEZE.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF. SHRA/TSRA POSSIBLE BY THE
LATE MORNING HOURS.

OUTLOOK...SATURDAY THROUGH MONDAY...

HIGH CONFIDENCE. MOSTLY VFR WITH SCT-BKN DIURNAL CU. LATE
NIGHT/EARLY MORNING PATCHY MVFR/IFR FOG POSSIBLE IN THE CT VALLEY.
WIDELY SCT SHOWERS/TSTMS POSSIBLE WESTERN AREAS LATE MON.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

OVERVIEW /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.

WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. WORTHY
OF MENTION THAT SOUTHWEST WINDS WILL INCREASE WITH GUSTS UP TO 20
KTS POSSIBLE TODAY MAINLY ALONG THE SOUTH SHORE. SHOWERS AND
THUNDERSTORMS MAY BE ON THE INCREASE AHEAD OF A SURFACE COLD FRONT
ANTICIPATED TO SWEEP INTO THE WATERS CLOSER TO FRIDAY MORNING AND
CLEARING OUT BY FRIDAY LATE. BEHIND THE FRONT...WINDS WILL BACK
OUT OF THE NORTHWEST.

OUTLOOK...SATURDAY THROUGH MONDAY...

HIGH CONFIDENCE.

EXPECT WINDS AND SEAS TO REMAIN BELOW SCA THRESHOLDS FOR MOST OF THE
PERIOD. HOWEVER...SW WINDS COULD GUST TO 20+ KTS MON/MON NIGHT WITH
SEAS POSSIBLY BUILDING TO 5 FT OVER OUTER SOUTHERN WATERS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...KJC/SIPPRELL
NEAR TERM...DUNTEN/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...KJC
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL




AREA FORECAST DISCUSSION

NWS TAUNTON MA

 720 AM EDT THU AUG 22 2013

.SYNOPSIS...
CONTINUED WARM AND MUGGY CONDITIONS AHEAD OF A SERIES OF WET
WEATHER DISTURBANCES TODAY INTO FRIDAY. SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED...CLEARING OUT BY AS LATE AS FRIDAY NIGHT.
THEREAFTER DRY AND NEAR SEASONABLE WEATHER WILL RETURN THIS
WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION. MORE HUMID
CONDITIONS AND PERIODS OF UNSETTLED WEATHER MOVES IN NEXT WEEK AS
A WARM FRONT MOVES INTO THE REGION.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
715 AM UPDATE...
WV IMAGERY SHOWS MID LEVEL SHORTWAVE MOVING SLOWLY EAST FROM WV.
AHEAD OF THIS IMPULSE...THERE WERE SCATTERED SHOWERS AND ISOLD
TSTMS FROM NE PA AND NJ TO SOUTH OF LI WHICH IS ALONG THE LEADING
EDGE OF THE KI GRADIENT. MODELS BRING THE HIGHER KI VALUES INTO
SNE LATER THIS MORNING INTO THE AFTERNOON AS THE SHORTWAVE
APPROACHES THE MID ATLC COAST. THIS WILL RESULT IN AN INCREASED
THREAT OF SHOWERS/TSTMS. CURRENT FORECAST POPS LOOK REASONABLE.
PATCHY FOG/STRATUS WILL BURN OFF BY MID MORNING.

PREVIOUS DISCUSSION...

FOCUS WILL BE ON THE DEAMPLIFYING MID-LEVEL LOW PRESSURE TRACKING
EAST ACROSS THE DELMARVA OUT TO SEA. SQUEEZING UP AGAINST ATLANTIC
HIGH PRESSURE AND PUSHED BY A STRONGER SHORTWAVE AND TROUGH AXIS
APPROACHING FROM THE EASTERN GREAT LAKES WILL YIELD AMPLIFICATION
OF MID- TO UPPER-LEVEL TROPOSPHERIC WINDS PROMOTING GREATER
DIFFLUENCE ALOFT. IN RESPONSE...SHOULD SEE AN ENHANCEMENT OF
SOUTHERLY FLOW WITHIN THE LOW-LEVELS ADVECTING MORE MUGGY
CONDITIONS INTO SOUTHERN NEW ENGLAND AGAINST DRIER AIR /GUSTS UP
TO 20 MPH ALONG THE SOUTH COAST/. SUBSEQUENT MOISTENING TO THE
WET-BULB OF THE ATMOSPHERIC PROFILE SHOULD ALLOW THE BUILD UP OF
ELEVATED INSTABILITY.

FEEL ANY ACTIVITY TODAY WILL BE LOCALIZED MAINLY SOUTH AND WEST IN
REGIONS OF FAVORABLE LIFT ALOFT COLLOCATED WITH AREAS OF LOW-LEVEL
CONVERGENCE THAT CAPITALIZE ON THE GROWING INSTABILITY...ESPECIALLY
IF THE BOUNDARY LAYER HAS AN OPPORTUNITY TO DESTABILIZE. STILL
DIFFICULT TO PIN-POINT...BUT FEEL AREAS NORTH AND EAST MAY REMAIN
UNDER THE INFLUENCE OF DRIER AND SINKING AIR.

GREATER CONFIDENCE WITH THE LATEST HRRR AND 22.0Z NAM HIGHLIGHTING
SOME EARLY MORNING ACTIVITY COLLOCATED WITH THE NOSE OF A LOW-LEVEL
JET AXIS JUST ABOVE THE DECOUPLED BOUNDARY LAYER. ACTIVITY OCCURRING
ACROSS NORTHEAST PENNSYLVANIA SHOULD FOCUS EASTWARD WITH TIME. BUT
OTHERWISE...A MAJORITY OF THE FORECAST AREA MAY SIMPLY REMAIN PARTLY
CLOUDY AND DRY...ALLOWING HIGHS TO GET INTO THE MID- TO UPPER-80S...
WITH A FEW LOCATIONS AT OR ABOVE THE 90 DEGREE MARK FOR A SECOND DAY
IN A ROW.

CONSIDERING A WEAK SHEAR ENVIRONMENT WITH MODEST INSTABILITY ALONG
WITH NEAR-ZERO CORFIDI VECTORS AND A WEAK MEAN ATMOSPHERIC FLOW
AROUND 15 MPH...MAIN THREATS ASSOCIATED WITH ANY STORMS APPEAR TO
BE HEAVY RAIN AND POSSIBLE NUISANCE FLOODING /PWATS CONTINUE TO
RANGE AROUND 1.5 TO 1.75 INCHES/. COULD SEE SOME GUSTY WINDS
SHOULD THE BOUNDARY LAYER MIX-OUT WITH INVERTED-V PROFILES.

ACTIVITY ALONG THE UPSTREAM COLD FRONT WILL NOT PUSH INTO THE
FORECAST REGION UNTIL EVENING.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...

STRONGER SHORTWAVE AND TROUGH AXIS WITH ATTENDANT SURFACE COLD FRONT
WILL SWEEP THROUGH THE REGION REACHING SOUTHEAST MASSACHUSETTS BY
MORNING. ANTICIPATING SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF
THE COLD FRONT AIDED BY STRONG FRONTOGENETICAL LIFT. INITIALLY
PUSHING INTO WESTERN NEW ENGLAND BY EVENING...ACTIVITY LOOKS TO
DIMINISH EASTWARD TOWARDS BY MIDNIGHT INTO MORNING AS BETTER
DYNAMICS ALOFT LIFT NORTH AND EAST PARENT WITH THE MID-LEVEL LOW.

WITH A STABILIZING BOUNDARY LAYER PROFILE...FEEL ANY STORMS WILL BE
MAINLY ASSOCIATED WITH HEAVY RAIN. LESSER CONFIDENCE FOR NUISANCE
FLOODING AS THE BETTER PWAT ENVIRONMENT WILL BE WELL SOUTH AND EAST
OFFSHORE OF THE REGION. LOWS AROUND THE MID-60S.

FRIDAY...

SURFACE COLD FRONT SLOWS OFFSHORE...STALLING SOUTH OF SOUTHERN NEW
ENGLAND. CLOUDS AND SHOWERS WILL LINGER FOR THE FAR SOUTH-SOUTHEAST
PORTIONS OF THE FORECAST AREA. NORTHWEST FLOW PREVAILS PUSHING
COOLER AND DRIER AIR SOUTH WITHIN THE LOW- TO MID-LEVELS.

EXPECTING DEEP BOUNDARY LAYER MIXING UP TO H8 LENDING TO SCATTERED
TO BROKEN DIURNAL CUMULUS AND THE POSSIBILITY FOR SOME SPOTTY
SHOWERS CAPITALIZING ON THE LIFT OF MINOR ELEVATED INSTABILITY AHEAD
OF A REINFORCING SECONDARY COLD FRONT. WILL INSERT SLIGHT CHANCE
POPS FOR A MAJORITY OF THE FORECAST REGION FOR THE MIDDAY INTO
AFTERNOON PERIOD. WILL ALSO SEE THE MIX-DOWN OF DRIER AIR AND FASTER
MOMENTUM. WIND GUSTS AROUND 15 MPH EXPECTED WITH HIGHS AROUND THE
LOW-80S...COOLER ALONG THE SHORES AND HIGHER ELEVATIONS.

FRIDAY NIGHT...

REINFORCING COLD FRONT PUSHES WELL OFFSHORE PARENT WITH ANOTHER MID-
LEVEL TROUGH AXIS SWEEPING ACROSS NEW ENGLAND. WINDS BACK MORE
NORTHERLY CONTINUALLY ADVECTING MORE COOLER AND DRIER AIR SOUTHWARD
OUT OF CANADA. LOOKING AT A POTENTIALLY CHILLY NIGHT SHOULD
CONDITIONS REMAIN MOSTLY CLEAR. LOWS AROUND THE MID-50S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
HIGHLIGHTS...

* DRY AND COOLER SAT...THEN WARMER SUNDAY
* BECOMING MORE HUMID NEXT WEEK WITH UNSETTLED WEATHER POSSIBLE FROM
  TIME TO TIME.

OVERVIEW...
GUIDANCE IN GOOD AGREEMENT ON OVERALL PATTERN DURING THE EXTENDED
PERIOD. MID LEVEL TROF WHICH WILL BRING COOLER WEATHER TO START THE
WEEKEND WILL BE EXITING THE REGION BY SUNDAY. MODELS AGREE ON AN
ANOMALOUS AND EXPANSIVE MID LEVEL RIDGE BUILDING ACROSS THE CENTRAL
CONUS DURING MUCH OF THE PERIOD WITH SNE REMAINING ON THE SOUTHERN
EDGE OF THE POLAR JET WITH MAINLY NW FLOW ALOFT.  THIS WILL KEEP THE
SIGNIFICANT HEAT WEST OF SNE AND ALSO MAKE US SUSCEPTIBLE TO
OCCASIONAL IMPULSES IN NW FLOW BEGINNING NEXT WEEK. THE TIMING AND
AMPLITUDE OF INDIVIDUAL SHORTWAVES WILL DETERMINE THE COVERAGE AND
INTENSITY OF SHOWERS AND THUNDERSTORMS...BUT THE THREAT WILL EXIST
SOMETIME FROM LATE MON INTO WED.

SATURDAY AND SUNDAY...
STRONG HIGH PRES BUILDS ACROSS SNE GRADUALLY SHIFTING TO THE S ON
SUNDAY.  FOR SAT...NEARBY MID LEVEL TROF AND COLD POOL ACTING ON LOW
LEVEL MOISTURE WILL LIKELY BRING AT LEAST SCT-BKN CU BUT THE
MOISTURE IS SHALLOW SO DRY WEATHER EXPECTED.  LESS CU ON SUNDAY AS
MID LEVEL TEMPS WARM. TEMPS WILL BE A FEW DEGREES BELOW NORMAL
SAT...MOSTLY IN THE MID/UPPER 70S THEN WARMING INTO UPPER 70S AND
LOWER 80S SUNDAY IN RESPONSE TO INCREASING MID LEVEL TEMPS.

MONDAY...
SOME DIFFERENCES BETWEEN GFS AND ECMWF BEGIN TO SHOW UP REGARDING
THE EASTWARD EXTENT OF THE WARM FRONT. GFS APPEARS TO MOVE THE WARM
FRONT THROUGH TOO QUICKLY. PREFER THE ECMWF KEEPING THE FRONT TO THE
WEST GIVEN THE NW FLOW ALOFT. MOST OF THE REGION SHOULD REMAIN DRY
ALTHOUGH CANT RULE OUT A FEW SHOWERS OR A THUNDERSTORM ACROSS W
ZONES LATE IN THE DAY AS MOISTURE INCREASES FROM THE WEST.

MONDAY NIGHT INTO WEDNESDAY...
IT APPEARS FRONTAL BOUNDARY MAY GET HUNG UP NEAR SNE DURING THIS
PERIOD. THIS WILL BRING THE THREAT OF SHOWERS AND THUNDERSTORMS FROM
TIME TO TIME BUT WE HAVE LOW CONFIDENCE IN TIMING AS THERE ARE
DIFFERENCES IN THE MODELS. HUMIDITY WILL BE INCREASING ALTHOUGH THE
HEAT WILL REMAIN TO THE WEST WITH TEMPS MOSTLY NEAR SEASONABLE
NORMALS.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

OVERVIEW /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.

AREAS OF MVFR/IFR FOG AND STRATUS WILL BURN OFF BY MID
MORNING...BUT MAY LINGER A FEW HOURS LATER AT ACK.
SHRA/TSRA WILL BE ON THE INCREASE FROM THE SOUTH AND WEST.
MENTIONED VCSH FOR NOW WITH OVERWHELMING UNCERTAINTY ON THE
EVOLUTION AND POTENTIAL IMPACTS OF SHRA/TSRA. SOUTHWEST WINDS
PREVAILING WITH GUSTS UP TO AROUND 20 KTS.

ACTIVITY CLEARS UP INTO FRIDAY MORNING WITH A COLD FRONT SWEEPING
ACROSS THE TERMINALS...WINDS BACKING WEST-NORTHWEST. MAY SEE A
SPOT SHRA/TSRA DURING THE DAY FRIDAY...BUT A REINFORCING COLD
FRONT WITH NORTH-NORTHWEST FLOW TO THE REAR SHOULD PUSH ALL
REMAINING ACTIVITY OFFSHORE.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. NO EXPECTATION FOR A SEA-
BREEZE.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF. SHRA/TSRA POSSIBLE BY THE
LATE MORNING HOURS.

OUTLOOK...SATURDAY THROUGH MONDAY...

HIGH CONFIDENCE. MOSTLY VFR WITH SCT-BKN DIURNAL CU. LATE
NIGHT/EARLY MORNING PATCHY MVFR/IFR FOG POSSIBLE IN THE CT VALLEY.
WIDELY SCT SHOWERS/TSTMS POSSIBLE WESTERN AREAS LATE MON.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

OVERVIEW /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.

WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. WORTHY
OF MENTION THAT SOUTHWEST WINDS WILL INCREASE WITH GUSTS UP TO 20
KTS POSSIBLE TODAY MAINLY ALONG THE SOUTH SHORE. SHOWERS AND
THUNDERSTORMS MAY BE ON THE INCREASE AHEAD OF A SURFACE COLD FRONT
ANTICIPATED TO SWEEP INTO THE WATERS CLOSER TO FRIDAY MORNING AND
CLEARING OUT BY FRIDAY LATE. BEHIND THE FRONT...WINDS WILL BACK
OUT OF THE NORTHWEST.

OUTLOOK...SATURDAY THROUGH MONDAY...

HIGH CONFIDENCE.

EXPECT WINDS AND SEAS TO REMAIN BELOW SCA THRESHOLDS FOR MOST OF THE
PERIOD. HOWEVER...SW WINDS COULD GUST TO 20+ KTS MON/MON NIGHT WITH
SEAS POSSIBLY BUILDING TO 5 FT OVER OUTER SOUTHERN WATERS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KJC/SIPPRELL
NEAR TERM...KJC/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...KJC
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL




AREA FORECAST DISCUSSION

NWS TAUNTON MA

 330 AM EDT THU AUG 22 2013

.SYNOPSIS...

CONTINUED WARM AND MUGGY CONDITIONS AHEAD OF A SERIES OF WET
WEATHER DISTURBANCES TODAY INTO FRIDAY. SCATTERED SHOWERS AND
THUNDERSTORMS EXPECTED...CLEARING OUT BY AS LATE AS FRIDAY NIGHT.
THEREAFTER DRY AND NEAR SEASONABLE WEATHER WILL RETURN THIS
WEEKEND AS HIGH PRESSURE BUILDS ACROSS THE REGION. MORE HUMID
CONDITIONS AND PERIODS OF UNSETTLED WEATHER MOVES IN NEXT WEEK AS
A WARM FRONT MOVES INTO THE REGION.

&&

.NEAR TERM /THROUGH TODAY/...

4 AM UPDATE...

SCATTERED SHOWER AND THUNDERSTORM ACTIVITY ACROSS NORTHEAST
PENNSYLVANIA COLLOCATED WITHIN A REGION OF FAVORABLE ENHANCED
ASCENT AND PERHAPS SOME LOCALIZED CONVERGENCE OF LOW-LEVEL WINDS
SHOULD GRADUALLY PUSH EASTWARD...BUT PERHAPS BECOMING DELAYED BY
OVERWHELMING DRY AIR ACROSS THE FORECAST REGION.

HRRR IS NOT FORECASTING OUTCOMES VERY WELL WITH LATEST GUIDANCE.
WOULD ASSUME THE BETTER ACTIVITY REMAINS SOUTH AND WEST PRIOR TO
THE MORNING HOURS. DURING SUCH TIME...LOW CLOUDS AND FOG WILL
CONTINUE TO HAMPER THE SOUTH COAST WITH VISIBILITIES DOWN TO A
HALF A MILE OR LESS.

TODAY...

FOCUS WILL BE ON THE DEAMPLIFYING MID-LEVEL LOW PRESSURE TRACKING
EAST ACROSS THE DELMARVA OUT TO SEA. SQUEEZING UP AGAINST ATLANTIC
HIGH PRESSURE AND PUSHED BY A STRONGER SHORTWAVE AND TROUGH AXIS
APPROACHING FROM THE EASTERN GREAT LAKES WILL YIELD AMPLIFICATION OF
MID- TO UPPER-LEVEL TROPOSPHERIC WINDS PROMOTING GREATER DIFFLUENCE
ALOFT. IN RESPONSE...SHOULD SEE AN ENHANCEMENT OF SOUTHERLY FLOW
WITHIN THE LOW-LEVELS ADVECTING MORE MUGGY CONDITIONS INTO SOUTHERN
NEW ENGLAND AGAINST DRIER AIR /GUSTS UP TO 20 MPH ALONG THE SOUTH
COAST/. SUBSEQUENT MOISTENING TO THE WET-BULB OF THE ATMOSPHERIC
PROFILE SHOULD ALLOW THE BUILD UP OF ELEVATED INSTABILITY.

FEEL ANY ACTIVITY TODAY WILL BE LOCALIZED MAINLY SOUTH AND WEST IN
REGIONS OF FAVORABLE LIFT ALOFT COLLOCATED WITH AREAS OF LOW-LEVEL
CONVERGENCE THAT CAPITALIZE ON THE GROWING INSTABILITY...ESPECIALLY
IF THE BOUNDARY LAYER HAS AN OPPORTUNITY TO DESTABILIZE. STILL
DIFFICULT TO PIN-POINT...BUT FEEL AREAS NORTH AND EAST MAY REMAIN
UNDER THE INFLUENCE OF DRIER AND SINKING AIR.

GREATER CONFIDENCE WITH THE LATEST HRRR AND 22.0Z NAM HIGHLIGHTING
SOME EARLY MORNING ACTIVITY COLLOCATED WITH THE NOSE OF A LOW-LEVEL
JET AXIS JUST ABOVE THE DECOUPLED BOUNDARY LAYER. ACTIVITY OCCURRING
ACROSS NORTHEAST PENNSYLVANIA SHOULD FOCUS EASTWARD WITH TIME. BUT
OTHERWISE...A MAJORITY OF THE FORECAST AREA MAY SIMPLY REMAIN PARTLY
CLOUDY AND DRY...ALLOWING HIGHS TO GET INTO THE MID- TO UPPER-80S...
WITH A FEW LOCATIONS AT OR ABOVE THE 90 DEGREE MARK FOR A SECOND DAY
IN A ROW.

CONSIDERING A WEAK SHEAR ENVIRONMENT WITH MODEST INSTABILITY ALONG
WITH NEAR-ZERO CORFIDI VECTORS AND A WEAK MEAN ATMOSPHERIC FLOW
AROUND 15 MPH...MAIN THREATS ASSOCIATED WITH ANY STORMS APPEAR TO
BE HEAVY RAIN AND POSSIBLE NUISANCE FLOODING /PWATS CONTINUE TO
RANGE AROUND 1.5 TO 1.75 INCHES/. COULD SEE SOME GUSTY WINDS
SHOULD THE BOUNDARY LAYER MIX-OUT WITH INVERTED-V PROFILES.

ACTIVITY ALONG THE UPSTREAM COLD FRONT WILL NOT PUSH INTO THE
FORECAST REGION UNTIL EVENING.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...

TONIGHT...

STRONGER SHORTWAVE AND TROUGH AXIS WITH ATTENDANT SURFACE COLD FRONT
WILL SWEEP THROUGH THE REGION REACHING SOUTHEAST MASSACHUSETTS BY
MORNING. ANTICIPATING SHOWERS AND THUNDERSTORMS ALONG AND AHEAD OF
THE COLD FRONT AIDED BY STRONG FRONTOGENETICAL LIFT. INITIALLY
PUSHING INTO WESTERN NEW ENGLAND BY EVENING...ACTIVITY LOOKS TO
DIMINISH EASTWARD TOWARDS BY MIDNIGHT INTO MORNING AS BETTER
DYNAMICS ALOFT LIFT NORTH AND EAST PARENT WITH THE MID-LEVEL LOW.

WITH A STABILIZING BOUNDARY LAYER PROFILE...FEEL ANY STORMS WILL BE
MAINLY ASSOCIATED WITH HEAVY RAIN. LESSER CONFIDENCE FOR NUISANCE
FLOODING AS THE BETTER PWAT ENVIRONMENT WILL BE WELL SOUTH AND EAST
OFFSHORE OF THE REGION. LOWS AROUND THE MID-60S.

FRIDAY...

SURFACE COLD FRONT SLOWS OFFSHORE...STALLING SOUTH OF SOUTHERN NEW
ENGLAND. CLOUDS AND SHOWERS WILL LINGER FOR THE FAR SOUTH-SOUTHEAST
PORTIONS OF THE FORECAST AREA. NORTHWEST FLOW PREVAILS PUSHING
COOLER AND DRIER AIR SOUTH WITHIN THE LOW- TO MID-LEVELS.

EXPECTING DEEP BOUNDARY LAYER MIXING UP TO H8 LENDING TO SCATTERED
TO BROKEN DIURNAL CUMULUS AND THE POSSIBILITY FOR SOME SPOTTY
SHOWERS CAPITALIZING ON THE LIFT OF MINOR ELEVATED INSTABILITY AHEAD
OF A REINFORCING SECONDARY COLD FRONT. WILL INSERT SLIGHT CHANCE
POPS FOR A MAJORITY OF THE FORECAST REGION FOR THE MIDDAY INTO
AFTERNOON PERIOD. WILL ALSO SEE THE MIX-DOWN OF DRIER AIR AND FASTER
MOMENTUM. WIND GUSTS AROUND 15 MPH EXPECTED WITH HIGHS AROUND THE
LOW-80S...COOLER ALONG THE SHORES AND HIGHER ELEVATIONS.

FRIDAY NIGHT...

REINFORCING COLD FRONT PUSHES WELL OFFSHORE PARENT WITH ANOTHER MID-
LEVEL TROUGH AXIS SWEEPING ACROSS NEW ENGLAND. WINDS BACK MORE
NORTHERLY CONTINUALLY ADVECTING MORE COOLER AND DRIER AIR SOUTHWARD
OUT OF CANADA. LOOKING AT A POTENTIALLY CHILLY NIGHT SHOULD
CONDITIONS REMAIN MOSTLY CLEAR. LOWS AROUND THE MID-50S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...

HIGHLIGHTS...

* DRY AND COOLER SAT...THEN WARMER SUNDAY
* BECOMING MORE HUMID NEXT WEEK WITH UNSETTLED WEATHER POSSIBLE FROM
  TIME TO TIME.

OVERVIEW...
GUIDANCE IN GOOD AGREEMENT ON OVERALL PATTERN DURING THE EXTENDED
PERIOD. MID LEVEL TROF WHICH WILL BRING COOLER WEATHER TO START THE
WEEKEND WILL BE EXITING THE REGION BY SUNDAY. MODELS AGREE ON AN
ANOMALOUS AND EXPANSIVE MID LEVEL RIDGE BUILDING ACROSS THE CENTRAL
CONUS DURING MUCH OF THE PERIOD WITH SNE REMAINING ON THE SOUTHERN
EDGE OF THE POLAR JET WITH MAINLY NW FLOW ALOFT.  THIS WILL KEEP THE
SIGNIFICANT HEAT WEST OF SNE AND ALSO MAKE US SUSCEPTIBLE TO
OCCASIONAL IMPULSES IN NW FLOW BEGINNING NEXT WEEK. THE TIMING AND
AMPLITUDE OF INDIVIDUAL SHORTWAVES WILL DETERMINE THE COVERAGE AND
INTENSITY OF SHOWERS AND THUNDERSTORMS...BUT THE THREAT WILL EXIST
SOMETIME FROM LATE MON INTO WED.

SATURDAY AND SUNDAY...
STRONG HIGH PRES BUILDS ACROSS SNE GRADUALLY SHIFTING TO THE S ON
SUNDAY.  FOR SAT...NEARBY MID LEVEL TROF AND COLD POOL ACTING ON LOW
LEVEL MOISTURE WILL LIKELY BRING AT LEAST SCT-BKN CU BUT THE
MOISTURE IS SHALLOW SO DRY WEATHER EXPECTED.  LESS CU ON SUNDAY AS
MID LEVEL TEMPS WARM. TEMPS WILL BE A FEW DEGREES BELOW NORMAL
SAT...MOSTLY IN THE MID/UPPER 70S THEN WARMING INTO UPPER 70S AND
LOWER 80S SUNDAY IN RESPONSE TO INCREASING MID LEVEL TEMPS.

MONDAY...
SOME DIFFERENCES BETWEEN GFS AND ECMWF BEGIN TO SHOW UP REGARDING
THE EASTWARD EXTENT OF THE WARM FRONT. GFS APPEARS TO MOVE THE WARM
FRONT THROUGH TOO QUICKLY. PREFER THE ECMWF KEEPING THE FRONT TO THE
WEST GIVEN THE NW FLOW ALOFT. MOST OF THE REGION SHOULD REMAIN DRY
ALTHOUGH CANT RULE OUT A FEW SHOWERS OR A THUNDERSTORM ACROSS W
ZONES LATE IN THE DAY AS MOISTURE INCREASES FROM THE WEST.

MONDAY NIGHT INTO WEDNESDAY...
IT APPEARS FRONTAL BOUNDARY MAY GET HUNG UP NEAR SNE DURING THIS
PERIOD. THIS WILL BRING THE THREAT OF SHOWERS AND THUNDERSTORMS FROM
TIME TO TIME BUT WE HAVE LOW CONFIDENCE IN TIMING AS THERE ARE
DIFFERENCES IN THE MODELS. HUMIDITY WILL BE INCREASING ALTHOUGH THE
HEAT WILL REMAIN TO THE WEST WITH TEMPS MOSTLY NEAR SEASONABLE
NORMALS.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...

FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

OVERVIEW /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.

PREVAILING VFR WITH IFR CIGS/VSBYS ALONG THE SOUTH-SHORE GRADUALLY
DISSIPATING INTO THE MIDDAY HOURS. SHRA/TSRA WILL BE ON THE
INCREASE FROM THE SOUTH AND WEST. MENTIONED VCSH FOR NOW WITH
OVERWHELMING UNCERTAINTY ON THE EVOLUTION AND POTENTIAL IMPACTS OF
SHRA/TSRA. SOUTHWEST WINDS PREVAILING WITH GUSTS UP TO AROUND 20
KTS.

ACTIVITY CLEARS UP INTO FRIDAY MORNING WITH A COLD FRONT SWEEPING
ACROSS THE TERMINALS...WINDS BACKING WEST-NORTHWEST. MAY SEE A
SPOT SHRA/TSRA DURING THE DAY FRIDAY...BUT A REINFORCING COLD
FRONT WITH NORTH-NORTHWEST FLOW TO THE REAR SHOULD PUSH ALL
REMAINING ACTIVITY OFFSHORE.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. NO EXPECTATION FOR A SEA-
BREEZE.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF. SHRA/TSRA POSSIBLE BY THE
LATE MORNING HOURS CONTINUING THROUGH THE DAY.

OUTLOOK...SATURDAY THROUGH MONDAY...

HIGH CONFIDENCE. MOSTLY VFR WITH SCT-BKN DIURNAL CU. LATE
NIGHT/EARLY MORNING PATCHY MVFR/IFR FOG POSSIBLE IN THE CT VALLEY.
WIDELY SCT SHOWERS/TSTMS POSSIBLE WESTERN AREAS LATE MON.

&&

.MARINE...

FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

OVERVIEW /THROUGH FRIDAY NIGHT/...MODERATE CONFIDENCE.

WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. WORTHY
OF MENTION THAT SOUTHWEST WINDS WILL INCREASE WITH GUSTS UP TO 20
KTS POSSIBLE TODAY MAINLY ALONG THE SOUTH SHORE. SHOWERS AND
THUNDERSTORMS MAY BE ON THE INCREASE AHEAD OF A SURFACE COLD FRONT
ANTICIPATED TO SWEEP INTO THE WATERS CLOSER TO FRIDAY MORNING AND
CLEARING OUT BY FRIDAY LATE. BEHIND THE FRONT...WINDS WILL BACK
OUT OF THE NORTHWEST.

OUTLOOK...SATURDAY THROUGH MONDAY...

HIGH CONFIDENCE.

EXPECT WINDS AND SEAS TO REMAIN BELOW SCA THRESHOLDS FOR MOST OF THE
PERIOD. HOWEVER...SW WINDS COULD GUST TO 20+ KTS MON/MON NIGHT WITH
SEAS POSSIBLY BUILDING TO 5 FT OVER OUTER SOUTHERN WATERS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...

CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...KJC/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...KJC
AVIATION...KJC/SIPPRELL
MARINE...KJC/SIPPRELL




AREA FORECAST DISCUSSION

NWS TALLAHASSEE FL

 1017 AM EDT Thu Aug 22 2013

.NEAR TERM [Through Today]...
The regional large scale pattern is highlighted by trough along NE
Conus from New England to mid-Atlc low, a ridge from Carolina coast
to Bermuda, a TUTT over Cntrl Gulf of Mex and low moving slowly west
off of Wrn Cuba. Local area remains in weakness between TUTT to our
SW and Atlc ridge centered to our NE. Satellite shows a fairly deep
plume of tropical air in between TUTT and Cuba low moving nwwd
across our area. PWATs remain above 2 inches. Looking nwd, we can see
swwd push of drier air beginning to impede from the NW.

At surface, 1022mb high pressure ridging from the Atlc Wwd across
the SE states with the axis just north of the forecast area. This
puts us in an E/SE low level flow regime making today`s sea breeze
climatology a hybrid of type 1 and 2 or more likely a disturbed
pattern (see below). However, main feature of interest is an MCS
that developed in tropical plume between TUTT and Cuba lows and
moved Nwwd generating strong to severe storms over local coastal
waters and adjacent coasts...mainly from Gulf to Franklin counties
after sunrise. However, there is some subsidence and warming temps
on the NW periphery This reflected well in HRRR. As a result,
forecast updated earlier to account for very high POPs over these
areas with sharp drop in pops S-N. Radar also shows some convection
already developing across Ern portions of S/Cntrl GA. HRRR and radar
shows some weakening of the MCS as it moves over land in next few
hours.

During the rest of today, the deep layer Atlc ridging will sink Swd
as shortwave push off mid-Atlc coast and the TUTT will weaken Wwd.
the MCS will continue to weaken and shift WNW. Assocd cloudiness and
warming temps may delay onset of seabreeze generated convection.
Main aftn and eve concern will be seabreeze-mesoscale boundary
clashes and HRRR shows main area of concern will be S/Cntrl GA. With
cooler temps expected aloft by late aftn, some storms may be strong
to isold severe especially where breaks in clouds occur. Strong wind
gusts will be the primary threat. Brief heavy downpours will be
possible in these storms. Will go with 70-80% POPs over wrn waters
and adjacent coast. Otherwise, 60-40% SW-NE Pop gradient. Morning
plus aftn clouds especially SW  third of area will temper aftn highs
to mid 80s Walton county to low 90s ern most GA counties.

&&

.SHORT TERM [Tonight Through Saturday]...

Although much of the eastern part of the country will be under the
influence of mid/upper level short/long wave troughing, the local
area will remain south of the trough, under the influence of deep
layer ridging. The local weather pattern will be driven primarily
by typical seabreeze circulations, with the best chance for rain
across north Florida each afternoon. However, a punch of dry air
from the east may limit overall precip coverage across our SE Big
Bend counties on Thursday. Temperatures will remain near seasonal
levels.

&&

.LONG TERM [Saturday Night through Wednesday]...

The long term pattern through the middle part of next week should
trend towards drier/more typical summer weather for the most part.
We should see max temps in lower 90s for the most part.

&&

.Aviation...
[Through 12Z Friday] Isolated areas of dense fog and low CIGs should
start to burn off within in the next hour. A large cluster of
thunderstorms is currently located offshore, but expected to weaken
as it advances onshore. With the exception of VLD, where there are
ongoing TSRA, expect VCTS/TSRA beginning this afternoon at all
terminals and lasting til a couple hours after sunset. Will probably
see another round of low CIGs and visibilities tomorrow morning
before sunrise, but based purely on persistence, confidence is low
at this time except where it was included at ABY and VLD.

&&

.MARINE...
Winds and Seas will remain higher and gusty rest of today near any
stronger storms assocd with the MCS. Otherwise, a relatively weak
pressure pattern under the influence of surface high pressure will
result in winds and seas below headline levels through early next
week.

&&

.FIRE WEATHER...

No fire weather concerns are expected over the next week.

&&

.HYDROLOGY...

With many area rivers in flood stage, most have either crested or
are near crest as of this morning. The most notable rivers are the
Choctawhatchee, Chipola, and the Ochlockonee where levels have
reached moderate, or even major flood stage in the case of the
Choctawhatchee near Bruce. With a return to a more typical
precipitation pattern over the next couple of days, rivers should
see some relief allowing for declining levels through the weekend.

For more specific information on area rivers visit the following link:
http://water.weather.gov/ahps2/index.php?wfo=tae

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   92  73  92  71  93 / 50  30  40  30  40
Panama City   88  74  88  73  89 / 70  30  40  20  40
Dothan        90  71  91  71  93 / 40  30  30  30  30
Albany        92  72  92  71  93 / 40  20  20  20  30
Valdosta      93  72  93  70  91 / 50  20  20  20  40
Cross City    91  71  91  71  90 / 50  30  30  20  50
Apalachicola  89  74  87  72  89 / 70  30  30  30  30

&&

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

&&


NEAR TERM...Block
SHORT TERM...Harrigan
LONG TERM...Evans/Harrigan
AVIATION...Block/Navarro
MARINE...Block
FIRE WEATHER...Wool
HYDROLOGY...Harrigan







AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

 1005 AM EDT THU AUG 22 2013

.UPDATE...THE ATMOSPHERE REMAINS QUITE MOIST WITH PRECIPITABLE
WATER ON THE TBW SOUNDING AT 2.14 INCHES. THE WARMING SEEN IN THE
MID-LEVELS ON THIS MORNINGS 12Z TBW SOUNDING NEEDS SOME
DISCUSSION. THERE IS SOME SUBSIDENCE ON THE PERIPHERY OF THE MCS
OVER THE NORTHEAST GULF. THIS RESULTED IN SOME FAIRLY SIGNIFICANT
TEMPERATURE RISES ABOVE 600 MBS. AT FIRST GLANCE...THE SOUNDING
WOULD SEEM TO SUPPORT JUST YOUR MORE TYPICAL AFTERNOON STORMS WITH
GUSTY...BUT SUB-SEVERE WIND GUSTS. THE REALITY THOUGH IS THAT THE
MCS WILL WEAKEN AND MOVE AWAY FROM FLORIDA TODAY. MID-LEVEL
TEMPERATURES ARE LIKELY TO RETURN TO ABOUT WHERE THEY WERE
YESTERDAY...WITH THE 500 MB TEMPERATURE EXPECTED TO COOL BACK
TOWARD -8C BY 18Z. THE 500 MB TEMPERATURE AT CAPE CANAVERAL THIS
MORNING WAS -7.9C.

WITH THIS IN MIND...EXPECT ANOTHER ROUND OF STRONG TO SEVERE
THUNDERSTORMS THIS AFTERNOON. THE 11Z HRRR IS SHOWING AN INITIAL
BAND OF STORMS DROPPING SOUTHWESTWARD WITH AN OUTFLOW BOUNDARY
INTO THE NATURE COAST BY EARLY AFTERNOON...THEN THE EAST COAST SEA
BREEZE MOVES ACROSS AND INTERSECTS THE INITIAL CONVECTION. WHILE
ITS TOO EARLY TO PINPOINT WHERE THE STRONGEST STORMS WILL BE...IT
DOES LOOK LIKE MUCH OF OUR AREA WILL BE AFFECTED WITH THE BEST
CHANCES OVER THE INTERIOR DURING THE FIRST HALF OF THE AFTERNOON
THEN THE COASTAL AREAS DURING THE LATE AFTERNOON AND EVENING.

ONE THING TO WATCH FOR THAT IS NOT CURRENTLY REFLECTED IN OUR
FORECAST IS THE POTENTIAL FOR OUTFLOW BOUNDARIES COMING IN FROM
THE GULF AS THE MCS WEAKENS. THIS WOULD GREATLY ENHANCE THE LOW-
LEVEL CONVERGENCE AND UPDRAFT POTENTIAL THIS AFTERNOON.

FOR THE UPDATE...WILL RAISE RAIN CHANCES OVER THE INTERIOR INTO
THE LIKELY CATEGORY BETWEEN 2 AND 5 PM. I WILL ALSO ADD WORDING
FOR GUSTY WINDS IN THUNDERSTORMS THIS AFTERNOON.

THE UPDATES SHOULD BE OUT BY 1030 AM.

&&

.AVIATION...
EAST COAST SEA BREEZE WILL AGAIN PUSH WESTWARD PRODUCING
SCATTERED TO NUMEROUS AFTERNOON AND EARLY EVENING THUNDERSTORMS.
VCTS EXPECTED AT ALL TAF SITES BY 18Z WITH POTENTIAL 16Z
DEVELOPMENT OVER THE INTERIOR NEAR LAL. WILL TEMPO FOR TSRA AS
NECESSARY. VFR CONDITIONS WILL RETURN 0Z-2Z.

&&

.MARINE...
MCS OVER THE NORTHEAST GULF WILL CONTINUE TO WEAKEN AND MOVE AWAY.
WE COULD SEE BRIEF SEA BREEZES NEAR THE COAST...BUT FOR THE MOST
PART WE WILL SEE EAST TO SOUTHEAST FLOW OVER THE WATERS FOR THE
NEXT SEVERAL DAYS. TWEAKED THE WEATHER A BIT TO SHOW MORE
SCATTERED STORMS IN THE OFFSHORE WATERS THIS MORNING...BUT
OTHERWISE FEW CHANGES PLANNED.

&&

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

&&

$$

UPDATE/MARINE...JILLSON
AVIATION...BARRON






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
310 PM CDT THU AUG 22 2013

.DISCUSSION...

934 AM...MORNING UPDATE...INCREASED POPS FOR THE ENTIRE AREA
THROUGH EARLY/MID AFTERNOON. LARGE AREA OF SHOWERS WITH EMBEDDED
TSRA CONTINUES TO SLOWLY SAG SOUTH ACROSS THE SOUTHERN CWA.
CONVECTION OVER/ENTERING LASALLE COUNTY WILL HAVE THE HEAVIEST
RAINFALL RATES THAT MAY REACH 1 TO 2 INCHES PER HOUR IN SOME
LOCATIONS. OFF TO THE NORTHWEST...A LINE OF TSRA CONTINUES TO MOVE
EAST ACROSS SOUTHERN WI AND NORTHERN IL. WINDS GUSTED TO 43 KTS AT
KEFT JUST BEFORE THE TOP OF THE HOUR. WHILE STRONG WIND GUSTS WILL
REMAIN POSSIBLE ACROSS FAR NORTHERN IL...NOT ANTICIPATING ANY
WIDESPREAD SEVERE POTENTIAL. THIS COMPLEX IS ASSOCIATED WITH A
SHORTWAVE WHICH EVENTUALLY SLIDES SOUTHEAST ACROSS THE AREA LATE
THIS MORNING INTO EARLY THIS AFTERNOON...THUS EXPECT SHRA/TSRA TO
CONTINUE THROUGH EARLY/MID AFTERNOON AS IT SLIDES SOUTHEAST. HIGH
TEMPERATURES WILL LIKELY BE LOWER THAN CURRENTLY ADVERTISED AND
WILL NEED TO ADJUST THOSE SOON...THOUGH WITH SOME SUNSHINE BY LATE
AFTERNOON...ESPECIALLY ACROSS NORTHERN IL...COULD SEE SOME
RECOVERY BACK INTO THE LOWER 80S. CMS

//PREV DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* TIMING OF ENDING OF LIGHT RAIN SHOWERS...AND TIMING WIND SHIFT
  LATE THIS AFTERNOON AND EARLY EVENING.

07

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

MCS WITH WIDESPREAD SHOWERS OVER NORTHEAST IL TO CONTINUE TO WEAKEN
AS IT DRIFTS ESE AND DEPARTS NE IL DURING NEXT FEW HOURS THROUGH MID
AFTERNOON. THUNDERSTORMS SHOULD STAY SOUTH OF I-80 AND OVER SOUTHERN
LAKE MICHIGAN...BUT MODERATE RAIN SHOWERS STILL LIKELY UNTIL 20Z AT
ORD AND MDW WITH MVFR VSBYS AND CEILINGS POSSIBLE.

A COLD FRONT WHICH CURRENTLY STRETCHES FROM GRAND RAPIDS MI WSW TO
JUST NORTH OF CHICAGO TO WATERLOO IA WILL SAG SLOWLY SOUTHWARD
ACROSS THE CHICAGO METRO NEXT 1-3 HOURS THROUGH MID AFTERNOON.
TIMING THE WIND SHIFT WILL BE SOMEWHAT CHALLENGING WITH CURRENT
PROJECTIONS HAVING WEST WINDS 10-15 KTS AND GUSTS 13-18 KTS TO
SHIFT NNW BY 20Z AND NE AFTER 22Z AND DIMINISH TO 5-9 KTS LATE THIS
AFTERNOON AND EARLY EVENING. VFR CIGS OF 3-5K FT POSSIBLE BEHIND
THE FRONT DURING THIS AFTERNOON AND THEN SCATTERED OUT LATER THIS
AFTERNOON WITH BROKEN-OVC MID/HIGH CLOUDS LINGERING INTO THIS
EVENING. MVFR VSBYS WITH LIGHT FOG SHOULD STAY MORE INLAND TOWARD
RFD WHERE ENE WINDS BECOMING LIGHTER BETWEEN 08Z-14Z AND KEPT VFR
VSBYS AT ORD AND MDW. SCATTERED CLOUDS OVERNIGHT INTO FRIDAY WITH
ENE WINDS OF 7-10 KTS.

07

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

* MEDIUM CONIDENCE IN TIMING. SCATTERED LIGHT SHOWERS TO GRADUALLY
  DIMINISH FROM THE NW DURING MID AND LATE AFTERNOON AS MCS
  WEAKENS AND TRACKS ESE OUT OF NE IL INTO NORTHERN INDIANA AND SOUTHERN
  LOWER MI. VFR CEILINGS AND VISIBILITIES EXPECTED TO PREVAIL THROUGH
  FRIDAY.

* MEDIUM CONFIDENCE IN WIND...WEST WINDS OF 4 TO 9 KTS HAVING RECENTLY
  SHIFTED SSE ON BACK SIDE OF 1020 MB MESO-HIGH PRESSURE FROM WEAKENING
  MCS JUST SE OF CHICAGO. WINDS TO SHIFT NE IN THE NEXT FEW HOURS AS
  COLD FRONT NEAR THE WI/IL BORDER DROPS SOUTHWARD ACROSS THE CHICAGO
  METRO LATE THIS AFTERNOON. NE WINDS TO VEER ENE DURING TONIGHT AND
  CONTINUE FRIDAY IN THE 7-10 KT RANGE.

07

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 18Z...

FRIDAY NIGHT THROUGH WEDNESDAY...VFR.

07

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

&&

$$

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

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






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 1246 PM CDT THU AUG 22 2013

.DISCUSSION...

934 AM...MORNING UPDATE...INCREASED POPS FOR THE ENTIRE AREA
THROUGH EARLY/MID AFTERNOON. LARGE AREA OF SHOWERS WITH EMBEDDED
TSRA CONTINUES TO SLOWLY SAG SOUTH ACROSS THE SOUTHERN CWA.
CONVECTION OVER/ENTERING LASALLE COUNTY WILL HAVE THE HEAVIEST
RAINFALL RATES THAT MAY REACH 1 TO 2 INCHES PER HOUR IN SOME
LOCATIONS. OFF TO THE NORTHWEST...A LINE OF TSRA CONTINUES TO MOVE
EAST ACROSS SOUTHERN WI AND NORTHERN IL. WINDS GUSTED TO 43 KTS AT
KEFT JUST BEFORE THE TOP OF THE HOUR. WHILE STRONG WIND GUSTS WILL
REMAIN POSSIBLE ACROSS FAR NORTHERN IL...NOT ANTICIPATING ANY
WIDESPREAD SEVERE POTENTIAL. THIS COMPLEX IS ASSOCIATED WITH A
SHORTWAVE WHICH EVENTUALLY SLIDES SOUTHEAST ACROSS THE AREA LATE
THIS MORNING INTO EARLY THIS AFTERNOON...THUS EXPECT SHRA/TSRA TO
CONTINUE THROUGH EARLY/MID AFTERNOON AS IT SLIDES SOUTHEAST. HIGH
TEMPERATURES WILL LIKELY BE LOWER THAN CURRENTLY ADVERTISED AND
WILL NEED TO ADJUST THOSE SOON...THOUGH WITH SOME SUNSHINE BY LATE
AFTERNOON...ESPECIALLY ACROSS NORTHERN IL...COULD SEE SOME
RECOVERY BACK INTO THE LOWER 80S. CMS

//PREV DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* TIMING OF ENDING OF SHOWERS...WITH ASSOCIATED CIG AND VSBY
  REDUCTIONS AND TIMING WIND SHIFT AND SPEED.

07

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

MCS WITH WIDESPREAD SHOWERS OVER NORTHEAST IL TO CONTINUE TO
WEAKEN AS IT DRIFTS ESE AND DEPARTS NE IL DURING NEXT FEW HOURS
THROUGH MID AFTERNOON. THUNDERSTORMS SHOULD STAY SOUTH OF I-80 AND
OVER SOUTHERN LAKE MICHIGAN...BUT MODERATE RAIN SHOWERS STILL LIKELY
UNTIL 20Z AT ORD AND MDW WITH MVFR VSBYS AND CEILINGS POSSIBLE.

A COLD FRONT WHICH CURRENTLY STRETCHES FROM GRAND RAPIDS MI WSW TO
JUST NORTH OF CHICAGO TO WATERLOO IA WILL SAG SLOWLY SOUTHWARD
ACROSS THE CHICAGO METRO NEXT 1-3 HOURS THROUGH MID AFTERNOON.
TIMING THE WIND SHIFT WILL BE SOMEWHAT CHALLENGING WITH CURRENT
PROJECTIONS HAVING WEST WINDS 10-15 KTS AND GUSTS 13-18 KTS TO
SHIFT NNW BY 20Z AND NE AFTER 22Z AND DIMINISH TO 5-9 KTS LATE THIS
AFTERNOON AND EARLY EVENING. VFR CIGS OF 3-5K FT POSSIBLE BEHIND
THE FRONT DURING THIS AFTERNOON AND THEN SCATTERED OUT LATER THIS
AFTERNOON WITH BROKEN-OVC MID/HIGH CLOUDS LINGERING INTO THIS
EVENING. MVFR VSBYS WITH LIGHT FOG SHOULD STAY MORE INLAND TOWARD
RFD WHERE ENE WINDS BECOMING LIGHTER BETWEEN 08Z-14Z AND KEPT VFR
VSBYS AT ORD AND MDW. SCATTERED CLOUDS OVERNIGHT INTO FRIDAY WITH
ENE WINDS OF 7-10 KTS.

07


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

* MEDIUM CONIDENCE IN TIMING. WIDESPREAD SHOWERS TO GRADUALLY
  DIMINISH FROM THE WEST DURING MID AFTERNOON AROUND 20Z AS MCS
  WEAKENS AND TRACKS ESE ACROSS NE IL. POCKETS OF MODERATE RAINS
  POSSIBLE TIL 19Z-20Z WITH MVFR CEILINGS/VSBYS THOUGH
  THUNDERSTORMS SHOULD STAY SOUTH OF I-80 AND OVER SE LAKE
  MICHIGAN.

* MEDIUM CONFIDENCE IN WIND...WEST WINDS AROUND 10 KTS WITH GUSTS
  13-18 KTS TO SHIFT NNW BY 20Z AND NE AROUND 22Z AND GRADUALLY
  DIMINISH TO 5-9 KTS LATE THIS AFTERNOON AND EARLY EVENING AND
  DIMINISH FURTHER AFTER SUNSET AND VEER ENE LATE TONIGHT INTO FRI.

07

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 18Z...

FRIDAY NIGHT THROUGH WEDNESDAY...VFR.

07

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

&&

$$

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

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






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 939 AM CDT THU AUG 22 2013

.DISCUSSION...

934 AM...MORNING UPDATE...INCREASED POPS FOR THE ENTIRE AREA
THROUGH EARLY/MID AFTERNOON. LARGE AREA OF SHOWERS WITH EMBEDDED
TSRA CONTINUES TO SLOWLY SAG SOUTH ACROSS THE SOUTHERN CWA.
CONVECTION OVER/ENTERING LASALLE COUNTY WILL HAVE THE HEAVIEST
RAINFALL RATES THAT MAY REACH 1 TO 2 INCHES PER HOUR IN SOME
LOCATIONS. OFF TO THE NORTHWEST...A LINE OF TSRA CONTINUES TO MOVE
EAST ACROSS SOUTHERN WI AND NORTHERN IL. WINDS GUSTED TO 43 KTS AT
KEFT JUST BEFORE THE TOP OF THE HOUR. WHILE STRONG WIND GUSTS WILL
REMAIN POSSIBLE ACROSS FAR NORTHERN IL...NOT ANTICIPATING ANY
WIDESPREAD SEVERE POTENTIAL. THIS COMPLEX IS ASSOCIATED WITH A
SHORTWAVE WHICH EVENTUALLY SLIDES SOUTHEAST ACROSS THE AREA LATE
THIS MORNING INTO EARLY THIS AFTERNOON...THUS EXPECT SHRA/TSRA TO
CONTINUE THROUGH EARLY/MID AFTERNOON AS IT SLIDES SOUTHEAST. HIGH
TEMPERATURES WILL LIKELY BE LOWER THAN CURRENTLY ADVERTISED AND
WILL NEED TO ADJUST THOSE SOON...THOUGH WITH SOME SUNSHINE BY LATE
AFTERNOON...ESPECIALLY ACROSS NORTHERN IL...COULD SEE SOME
RECOVERY BACK INTO THE LOWER 80S. CMS

//PREV DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* TIMING AND COVERAGE OF TSRA AT OR NEAR THE TERMINALS...WITH
  ASSOCIATED CIG AND VSBY REDUCTIONS AND VARIABLE WINDS.

LENNING

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

A COUPLE AREAS OF CONCERN FOR SHOWERS AND/OR THUNDERSTORMS THROUGH
MID MORNING TODAY. CURRENTLY BOTH AREAS ARE WITHIN AN AREA OF
MODERATE INSTABILITY AHEAD OF A FRONT...ROUGHLY 1500 J/KG MUCAPE
THAT STRETCHES FROM NORTH CENTRAL IOWA ESE INTO NORTHERN ILLINOIS.
FIRST AREA IS IMMEDIATELY WEST OF THE CHICAGO TERMINALS STRETCHING
FROM ROUGHLY EFT THROUGH RFD AND NEAR JOT...ON THE NOSE OF VERY
MODEST MID LEVEL THETA E ADVECTION. MOST OF THIS AREA SHOULD SLIDE
SOUTH OF ORD BUT MAY GET NEAR MDW AS IT TRACKS SOUTHEAST DOWN THE
RIDGE AXIS THIS MORNING. OF CONCERN FOR ORD WILL BE THE NORTHERN
PORTION OF THIS LINE NEAR EFT THAT MAY TRACK NEAR THE TERMINAL
AROUND 13Z. FARTHER WEST...A SECOND AREA OF STRONG THUNDERSTORMS HAS
BEEN UNDERGOING A GRADUAL WEAKENING TREND AS IT MOVES AWAY FROM THE
BETTER MOISTURE TRANSPORT FROM THE LOW LEVEL JET FOCUSED OVER
EASTERN NEBRASKA AND WESTERN IOWA. A COUPLE NOTABLE CIRCULATIONS
EMBEDDED WITHIN THIS AREA ON RADAR IMAGERY...THE FIRST OF WHICH WILL
OVERTAKE THE FIRST LINE OF THUNDERSTORMS...MOVING NEAR OR JUST NORTH
OF RFD AROUND 14Z AND ORD BETWEEN 1530 AND 1600Z. OUT AHEAD OF THIS
FEATURE MAY BE THE MOST FAVORABLE PERIOD FOR THUNDERSTORMS. THAT
SAID THE FAVORABLE THETA E ADVECTION OVER THE AREA WILL HAVE SHIFTED
FARTHER EAST...WHICH SHOULD ALLOW THE GENERAL WEAKENING TREND TO
CONTINUE. THE IDEA FOR NOW IS FOR A SOME FESTERING SHOWERS TO MOVE
INTO THE CHICAGO AREA AROUND 13Z OR SO...THOUGH CANNOT RULE OUT SOME
ISOLATED LIGHTNING LINGERING THAT LATE INTO THE MORNING.

A COLD FRONT WHICH CURRENTLY STRETCHES FROM FAR NORTHERN LAKE
MICHIGAN WSW ACROSS CENTRAL WISCONSIN AND INTO SOUTHERN MINNESOTA
WILL CONTINUE TO SLOWLY SAG SOUTH THROUGH THE DAY. TIMING THE WIND
SHIFT MAY BECOME A BIT DIFFICULT DEPENDING ON THE EVOLUTION OF
THUNDERSTORMS THIS MORNING...BUT EXPECT THE FRONT TO PUSH THROUGH
THE AREA BETWEEN 14Z AND 16Z WITH WINDS SHIFTING TO NORTHERLY...THEN
NORTHEAST BEHIND. SOME MODELS SOUNDINGS INDICATE POTENTIALLY MVFR
CIGS BEHIND THE FRONT BUT MOS GUIDANCE CONTINUES TO HOLD OFF AND
DONT SEE MUCH INDICATION ON UPSTREAM OBS TO INCLUDE IN THE TAF.

BMD

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

* LOW TO MEDIUM CONIDENCE IN TIMING. ACTUALLY MAY NEED TO DELAY
  TRENDS AT ORD BY A COUPLE HOURS...WITH ARRIVAL OF TSRA ACTIVITY
  NOW MAYBE 17Z OR LATER.

* MEDIUM CONFIDENCE IN WIND...VSBY AND CIG IMPACTS.

LENNING

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

FRIDAY NIGHT THROUGH WEDNESDAY...VFR.

BMD

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

$$

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

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






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 934 AM CDT THU AUG 22 2013

.DISCUSSION...

934 AM...MORNING UPDATE...INCREASED POPS FOR THE ENTIRE AREA
THROUGH EARLY/MID AFTERNOON. LARGE AREA OF SHOWERS WITH EMBEDDED
TSRA CONTINUES TO SLOWLY SAG SOUTH ACROSS THE SOUTHERN CWA.
CONVECTION OVER/ENTERING LASALLE COUNTY WILL HAVE THE HEAVIEST
RAINFALL RATES THAT MAY REACH 1 TO 2 INCHES PER HOUR IN SOME
LOCATIONS. OFF TO THE NORTHWEST...A LINE OF TSRA CONTINUES TO MOVE
EAST ACROSS SOUTHERN WI AND NORTHERN IL. WINDS GUSTED TO 43 KTS AT
KEFT JUST BEFORE THE TOP OF THE HOUR. WHILE STRONG WIND GUSTS WILL
REMAIN POSSIBLE ACROSS FAR NORTHERN IL...NOT ANTICIPATING ANY
WIDESPREAD SEVERE POTENTIAL. THIS COMPLEX IS ASSOCIATED WITH A
SHORTWAVE WHICH EVENTUALLY SLIDES SOUTHEAST ACROSS THE AREA LATE
THIS MORNING INTO EARLY THIS AFTERNOON...THUS EXPECT SHRA/TSRA TO
CONTINUE THROUGH EARLY/MID AFTERNOON AS IT SLIDES SOUTHEAST. HIGH
TEMPERATURES WILL LIKELY BE LOWER THAN CURRENTLY ADVERTISED AND
WILL NEED TO ADJUST THOSE SOON...THOUGH WITH SOME SUNSHINE BY LATE
AFTERNOON...ESPECIALLY ACROSS NORTHERN IL...COULD SEE SOME
RECOVERY BACK INTO THE LOWER 80S. CMS

//PREV DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* A COUPLE ROUNDS OF THUNDERSTORMS MOVING ACROSS THE AREA THIS
  MORNING.
* WIND SHIFT TO THE NORTH AND NORTHEAST WITH FROPA MID TO LATE
  MORNING.
* POTENTIAL FOR MVFR CIGS BEHIND FRONT.

BMD

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

A COUPLE AREAS OF CONCERN FOR SHOWERS AND/OR THUNDERSTORMS THROUGH
MID MORNING TODAY. CURRENTLY BOTH AREAS ARE WITHIN AN AREA OF
MODERATE INSTABILITY AHEAD OF A FRONT...ROUGHLY 1500 J/KG MUCAPE
THAT STRETCHES FROM NORTH CENTRAL IOWA ESE INTO NORTHERN ILLINOIS.
FIRST AREA IS IMMEDIATELY WEST OF THE CHICAGO TERMINALS STRETCHING
FROM ROUGHLY EFT THROUGH RFD AND NEAR JOT...ON THE NOSE OF VERY
MODEST MID LEVEL THETA E ADVECTION. MOST OF THIS AREA SHOULD SLIDE
SOUTH OF ORD BUT MAY GET NEAR MDW AS IT TRACKS SOUTHEAST DOWN THE
RIDGE AXIS THIS MORNING. OF CONCERN FOR ORD WILL BE THE NORTHERN
PORTION OF THIS LINE NEAR EFT THAT MAY TRACK NEAR THE TERMINAL
AROUND 13Z. FARTHER WEST...A SECOND AREA OF STRONG THUNDERSTORMS HAS
BEEN UNDERGOING A GRADUAL WEAKENING TREND AS IT MOVES AWAY FROM THE
BETTER MOISTURE TRANSPORT FROM THE LOW LEVEL JET FOCUSED OVER
EASTERN NEBRASKA AND WESTERN IOWA. A COUPLE NOTABLE CIRCULATIONS
EMBEDDED WITHIN THIS AREA ON RADAR IMAGERY...THE FIRST OF WHICH WILL
OVERTAKE THE FIRST LINE OF THUNDERSTORMS...MOVING NEAR OR JUST NORTH
OF RFD AROUND 14Z AND ORD BETWEEN 1530 AND 1600Z. OUT AHEAD OF THIS
FEATURE MAY BE THE MOST FAVORABLE PERIOD FOR THUNDERSTORMS. THAT
SAID THE FAVORABLE THETA E ADVECTION OVER THE AREA WILL HAVE SHIFTED
FARTHER EAST...WHICH SHOULD ALLOW THE GENERAL WEAKENING TREND TO
CONTINUE. THE IDEA FOR NOW IS FOR A SOME FESTERING SHOWERS TO MOVE
INTO THE CHICAGO AREA AROUND 13Z OR SO...THOUGH CANNOT RULE OUT SOME
ISOLATED LIGHTNING LINGERING THAT LATE INTO THE MORNING.

A COLD FRONT WHICH CURRENTLY STRETCHES FROM FAR NORTHERN LAKE
MICHIGAN WSW ACROSS CENTRAL WISCONSIN AND INTO SOUTHERN MINNESOTA
WILL CONTINUE TO SLOWLY SAG SOUTH THROUGH THE DAY. TIMING THE WIND
SHIFT MAY BECOME A BIT DIFFICULT DEPENDING ON THE EVOLUTION OF
THUNDERSTORMS THIS MORNING...BUT EXPECT THE FRONT TO PUSH THROUGH
THE AREA BETWEEN 14Z AND 16Z WITH WINDS SHIFTING TO NORTHERLY...THEN
NORTHEAST BEHIND. SOME MODELS SOUNDINGS INDICATE POTENTIALLY MVFR
CIGS BEHIND THE FRONT BUT MOS GUIDANCE CONTINUES TO HOLD OFF AND
DONT SEE MUCH INDICATION ON UPSTREAM OBS TO INCLUDE IN THE TAF.

BMD

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

* MEDIUM CONFIDENCE IN TSRA IMPACTING THE TERMINALS AND TIMING.
* MEDIUM CONFIDENCE IN WIND TRENDS/TIMING SHIFT.
* LOW CONFIDENCE IN MVFR CIGS.

BMD

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

FRIDAY NIGHT THROUGH WEDNESDAY...VFR.

BMD

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

$$

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

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






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 647 AM CDT THU AUG 22 2013

.DISCUSSION...
630 AM CDT

HAVE INCREASED POPS THROUGH THIS MORNING WITH OBSERVATIONAL AND
ENVIRONMENTAL ANALYSIS TRENDS ALL SUPPORTING CONVECTIVE LONGEVITY
IN THE AREA. THE ARC OF STORMS EARLY THIS MORNING FROM ROCKFORD
SOUTHEASTWARD LOOKS TO BE ROOTED ON AN ELEVATED AREA OF ISENTROPIC
ASCENT AND FOCUS ON SOME FORM OF ELEVATED CONVERGENCE. ONE OF
THESE STORMS PUT DOWN A QUICK TWO PLUS INCHES IN ROCHELLE. THE
HIGH PWAT AIR AND DEEP INSTABILITY ALONG WITH LITTLE IN THE WAY OF
SHEAR WILL CONTINUE TO MAKE THESE A MAINLY LOCALIZED HEAVY RAIN
THREAT. FURTHER WEST AN ORGANIZED AREA OF CONVECTION IS
PROGRESSING EAST ACROSS NORTHEAST IA. WHILE THIS IS SHOWING A
SLIGHT DIMINISHING TREND IN LIGHTING AND SOMEWHAT IN
STRUCTURE...THIS IS BEING DRIVEN BY AN MCV AND LIKELY WILL
OVERCOME THE CURRENT CONVECTION IN NORTH CENTRAL IL. TOGETHER
THESE AREAS WILL PROVIDE WIDESPREAD ENOUGH CONVECTION FROM
ROCKFORD THROUGH THE WESTERN METRO TO WARRANT HIGHER POPS AND QPF.
THE SEVERE WEATHER THREAT STILL REMAINS LIMITED AND REGIONALLY
THERE HAVE NOT BEEN ANY STORMS TO APPROACH SEVERE LIMITS. HOWEVER
THE EARLIER STORM IN ROCHELLE DID HAVE 39 MPH AND ANY CLUSTERS OF
CONVECTION WILL LIKELY HAVE TEMPORARY GUSTS AT OR ABOVE THAT GIVEN
SOME POSSIBLE WATER LOADING AND HIGH DCAPE AIR.

MTF

//PREV DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* A COUPLE ROUNDS OF THUNDERSTORMS MOVING ACROSS THE AREA THIS
  MORNING.
* WIND SHIFT TO THE NORTH AND NORTHEAST WITH FROPA MID TO LATE
  MORNING.
* POTENTIAL FOR MVFR CIGS BEHIND FRONT.


BMD

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

A COUPLE AREAS OF CONCERN FOR SHOWERS AND/OR THUNDERSTORMS THROUGH
MID MORNING TODAY. CURRENTLY BOTH AREAS ARE WITHIN AN AREA OF
MODERATE INSTABILITY AHEAD OF A FRONT...ROUGHLY 1500 J/KG MUCAPE
THAT STRETCHES FROM NORTH CENTRAL IOWA ESE INTO NORTHERN ILLINOIS.
FIRST AREA IS IMMEDIATELY WEST OF THE CHICAGO TERMINALS STRETCHING
FROM ROUGHLY EFT THROUGH RFD AND NEAR JOT...ON THE NOSE OF VERY
MODEST MID LEVEL THETA E ADVECTION. MOST OF THIS AREA SHOULD SLIDE
SOUTH OF ORD BUT MAY GET NEAR MDW AS IT TRACKS SOUTHEAST DOWN THE
RIDGE AXIS THIS MORNING. OF CONCERN FOR ORD WILL BE THE NORTHERN
PORTION OF THIS LINE NEAR EFT THAT MAY TRACK NEAR THE TERMINAL
AROUND 13Z. FARTHER WEST...A SECOND AREA OF STRONG THUNDERSTORMS HAS
BEEN UNDERGOING A GRADUAL WEAKENING TREND AS IT MOVES AWAY FROM THE
BETTER MOISTURE TRANSPORT FROM THE LOW LEVEL JET FOCUSED OVER
EASTERN NEBRASKA AND WESTERN IOWA. A COUPLE NOTABLE CIRCULATIONS
EMBEDDED WITHIN THIS AREA ON RADAR IMAGERY...THE FIRST OF WHICH WILL
OVERTAKE THE FIRST LINE OF THUNDERSTORMS...MOVING NEAR OR JUST NORTH
OF RFD AROUND 14Z AND ORD BETWEEN 1530 AND 1600Z. OUT AHEAD OF THIS
FEATURE MAY BE THE MOST FAVORABLE PERIOD FOR THUNDERSTORMS. THAT
SAID THE FAVORABLE THETA E ADVECTION OVER THE AREA WILL HAVE SHIFTED
FARTHER EAST...WHICH SHOULD ALLOW THE GENERAL WEAKENING TREND TO
CONTINUE. THE IDEA FOR NOW IS FOR A SOME FESTERING SHOWERS TO MOVE
INTO THE CHICAGO AREA AROUND 13Z OR SO...THOUGH CANNOT RULE OUT SOME
ISOLATED LIGHTNING LINGERING THAT LATE INTO THE MORNING.

A COLD FRONT WHICH CURRENTLY STRETCHES FROM FAR NORTHERN LAKE
MICHIGAN WSW ACROSS CENTRAL WISCONSIN AND INTO SOUTHERN MINNESOTA
WILL CONTINUE TO SLOWLY SAG SOUTH THROUGH THE DAY. TIMING THE WIND
SHIFT MAY BECOME A BIT DIFFICULT DEPENDING ON THE EVOLUTION OF
THUNDERSTORMS THIS MORNING...BUT EXPECT THE FRONT TO PUSH THROUGH
THE AREA BETWEEN 14Z AND 16Z WITH WINDS SHIFTING TO NORTHERLY...THEN
NORTHEAST BEHIND. SOME MODELS SOUNDINGS INDICATE POTENTIALLY MVFR
CIGS BEHIND THE FRONT BUT MOS GUIDANCE CONTINUES TO HOLD OFF AND
DONT SEE MUCH INDICATION ON UPSTREAM OBS TO INCLUDE IN THE TAF.

BMD


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

* MEDIUM CONFIDENCE IN TSRA IMPACTING THE TERMINALS AND TIMING.
* MEDIUM CONFIDENCE IN WIND TRENDS/TIMING SHIFT.
* LOW CONFIDENCE IN MVFR CIGS.

BMD

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

FRIDAY NIGHT THROUGH WEDNESDAY...VFR.

BMD

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

$$

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

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






AREA FORECAST DISCUSSION...UPDATED

NWS CHICAGO/ROMEOVILLE IL

 630 AM CDT THU AUG 22 2013

.DISCUSSION...
630 AM CDT

HAVE INCREASED POPS THROUGH THIS MORNING WITH OBSERVATIONAL AND
ENVIRONMENTAL ANALYSIS TRENDS ALL SUPPORTING CONVECTIVE LONGEVITY
IN THE AREA. THE ARC OF STORMS EARLY THIS MORNING FROM ROCKFORD
SOUTHEASTWARD LOOKS TO BE ROOTED ON AN ELEVATED AREA OF ISENTROPIC
ASCENT AND FOCUS ON SOME FORM OF ELEVATED CONVERGENCE. ONE OF
THESE STORMS PUT DOWN A QUICK TWO PLUS INCHES IN ROCHELLE. THE
HIGH PWAT AIR AND DEEP INSTABILITY ALONG WITH LITTLE IN THE WAY OF
SHEAR WILL CONTINUE TO MAKE THESE A MAINLY LOCALIZED HEAVY RAIN
THREAT. FURTHER WEST AN ORGANIZED AREA OF CONVECTION IS
PROGRESSING EAST ACROSS NORTHEAST IA. WHILE THIS IS SHOWING A
SLIGHT DIMINISHING TREND IN LIGHTING AND SOMEWHAT IN
STRUCTURE...THIS IS BEING DRIVEN BY AN MCV AND LIKELY WILL
OVERCOME THE CURRENT CONVECTION IN NORTH CENTRAL IL. TOGETHER
THESE AREAS WILL PROVIDE WIDESPREAD ENOUGH CONVECTION FROM
ROCKFORD THROUGH THE WESTERN METRO TO WARRANT HIGHER POPS AND QPF.
THE SEVERE WEATHER THREAT STILL REMAINS LIMITED AND REGIONALLY
THERE HAVE NOT BEEN ANY STORMS TO APPROACH SEVERE LIMITS. HOWEVER
THE EARLIER STORM IN ROCHELLE DID HAVE 39 MPH AND ANY CLUSTERS OF
CONVECTION WILL LIKELY HAVE TEMPORARY GUSTS AT OR ABOVE THAT GIVEN
SOME POSSIBLE WATER LOADING AND HIGH DCAPE AIR.

MTF

&&

.PREV DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* CONVECTIVE TRENDS OVER THE NEXT SEVERAL HOURS...AND AGAIN LATE
  THIS MORNING AND EARLY AFTERNOON.
* WIND SHIFTING TO NORTH ONCE AGAIN LATE THURSDAY MORNING WITH A
  COLD FRONT.
* POTENTIAL FOR MVFR CIGS BEHIND THE FRONT.

BMD

//DISCUSSION...UPDATED 09Z...
ADDITIONAL THUNDERSTORMS ARE DEVELOPING EARLY THIS MORNING WITHIN
A CORRIDOR OF UPWARDS OF 2000 J/KG MUCAPE THAT STRETCHES FROM
ROUGHLY NORTH CENTRAL IOWA INTO FAR NORTHERN ILLINOIS. COVERAGE IS
SOMEWHAT SCATTERED AT THE MOMENT AND EXPECT THIS TO REMAIN THE
CASE THROUGH THE EARLY MORNING. A CONVECTIVE COMPLEX MOVING EAST
ACROSS NORTH CENTRAL IOWA SHOWING SIGNS OF DEVELOPING AN MCV WHICH
IS EXPECTED TO MOVE INTO NORTH CENTRAL ILLINOIS AROUND 14Z AND
NORTHEAST ILLINOIS AROUND 15Z. IT IS QUITE POSSIBLE THAT THIS
COULD SPAWN ADDITIONAL THUNDERSTORMS OVER THE AREA 1-2 HOURS PRIOR
TO ITS ARRIVAL...THOUGH QUITE A BIT OF UNCERTAINTY STILL IN
EXACTLY WHERE THIS MAY DEVELOP WITH RESPECT TO THE TERMINALS...AND
COVERAGE.

PREVIOUS DISCUSSION...
SEVERAL CONCERNS IN THE SHORT TERM REVOLVING AROUND A COUPLE DIFFERENT
WINDOWS OF OPPORTUNITY FOR SHRA/TSRA...AND WIND DIRECTION WITH AN
OUTFLOW BOUNDARY RACING SOUTH DOWN LAKE MICHIGAN.

RADAR AND SATELLITE TRENDS INDICATE THAT CONVECTIVE ACTIVITY AND
COVERAGE IS GENERALLY ON DOWNWARD TREND. SEEMS REASONABLE FOR THIS
TREND TO CONTINUE AS WE FALL BEHIND A WAVE THAT IS MOVING AWAY FROM
THE AREA ACROSS LAKE MICHIGAN. THE LOW LEVEL JET SETS UP WELL TO OUR
WEST AND WOULD SUPPORT ONGOING CONVECTION OVER NEBRASKA/WESTERN
IOWA...BUT NOT LOCALLY.

ON AVERAGE...IR IMAGERY SHOWS WARMING CLOUD TOPS OVER THE
AREA...WITH THE COOLEST CLOUD TOPS BECOMING MUCH MORE ISOLATED. THE
AREA CURRENTLY OVER THE CHICAGO TERMINALS HAS LOST MOST OF ITS
LIGHTNING...EXCEPT ON THE SOUTHERN MOST STORMS WHICH WILL NOT IMPACT
THE TERMINALS. EXPECT THAT BY THE TIME THE 06Z TAFS GO INTO EFFECT
THIS AREA WILL BE SOUTH OF ORD...AND SHOULD CLEAR MDW BY 0630Z. NEXT
AREA OF CONCERN IS AN AREA OVER NORTHWEST ILLINOIS. IF THIS AREA
HOLDS TOGETHER...EXPECT IT TO BE THROUGH THE CHICAGO TERMINALS BY
AROUND 09Z. GIVEN THE DOWNWARD TRENDS THOUGH DO NOT ANTICIPATE THIS
TO IMPACT BEYOND RFD WHICH SHOULD CLEAR BY 730Z.

TO OUR NORTH...AN OUTFLOW BOUNDARY IS EVIDENT ON RADAR IMAGERY
RACING SOUTH ALONG THE COAST OF LAKE MICHIGAN. THE CONVECTION TO
SUSTAIN THIS PUSH DOWN THE LAKE HAS SHIFTED EAST OF THE
BOUNDARY...WHICH IS STRUGGLING TO PUSH VERY FAR INLAND...BUT THERE
ARE CURRENTLY NORTHEAST GUSTS OF AROUND 20-25 KTS ASSOCIATED WITH
THE BOUNDARY. WINDS ARE EXPECTED TO SHIFT NORTHEAST AND INCREASE
SHARPLY...THEN SHOULD SETTLE DOWN SHORTLY THEREAFTER AND RETURN
CLOCKWISE BACK TO A MORE SOUTHERLY WIND...AND EVENTUALLY
SOUTHWEST. BASED ON THE CURRENT TRAJECTORY...IT WILL BE NEAR
ORD...MDW...AND GYY BY 630Z.

DID NOT MAKE ANY BIG CHANGES BEYOND THE FIRST 6 HOURS OF THE TAF.
FRONTAL TIMING STILL APPEARS TO BE AROUND 14Z WITH WINDS SHIFTING
TO NORTH...THEN NORTHEAST BEHIND THE FRONT. CANT COMPLETELY RULE
OUT ADDITIONAL THUNDERSTORMS DEVELOPING NEARBY TOMORROW AS WE
QUICKLY DEVELOP MODERATE INSTABILITY OVER THE AREA...BUT IT
APPEARS THE BEST FORCING WILL SHIFT SOUTH OF THE TERMINALS. SOME
MODEL SOUNDINGS CONTINUE TO INDICATE THE POTENTIAL FOR MVFR CIGS
TO DEVELOP RIGHT BEHIND THE FRONT FOR A COUPLE HOURS...THOUGH MOS
GUIDANCE INDICATES CONDITIONS WILL REMAIN VFR BEHIND THE FRONT.

BMD

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

* LOW CONFIDENCE IN TSRA TRENDS THROUGH THE MORNING.
* LOW CONFIDENCE IN MVFR CIGS BEHIND FRONT.

BMD

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

FRIDAY...VFR. NORTHEAST WINDS.

SATURDAY...VFR. EASTERLY WINDS.

SUNDAY THROUGH TUESDAY...VFR.

RC

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

$$

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

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






AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 417 AM CDT THU AUG 22 2013

.DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* CONVECTIVE TRENDS OVER THE NEXT SEVERAL HOURS...AND AGAIN LATE
  THIS MORNING AND EARLY AFTERNOON.
* WIND SHIFTING TO NORTH ONCE AGAIN LATE THURSDAY MORNING WITH A
  COLD FRONT.
* POTENTIAL FOR MVFR CIGS BEHIND THE FRONT.

BMD

//DISCUSSION...UPDATED 09Z...
ADDITIONAL THUNDERSTORMS ARE DEVELOPING EARLY THIS MORNING WITHIN
A CORRIDOR OF UPWARDS OF 2000 J/KG MUCAPE THAT STRETCHES FROM
ROUGHLY NORTH CENTRAL IOWA INTO FAR NORTHERN ILLINOIS. COVERAGE IS
SOMEWHAT SCATTERED AT THE MOMENT AND EXPECT THIS TO REMAIN THE
CASE THROUGH THE EARLY MORNING. A CONVECTIVE COMPLEX MOVING EAST
ACROSS NORTH CENTRAL IOWA SHOWING SIGNS OF DEVELOPING AN MCV WHICH
IS EXPECTED TO MOVE INTO NORTH CENTRAL ILLINOIS AROUND 14Z AND
NORTHEAST ILLINOIS AROUND 15Z. IT IS QUITE POSSIBLE THAT THIS
COULD SPAWN ADDITIONAL THUNDERSTORMS OVER THE AREA 1-2 HOURS PRIOR
TO ITS ARRIVAL...THOUGH QUITE A BIT OF UNCERTAINTY STILL IN
EXACTLY WHERE THIS MAY DEVELOP WITH RESPECT TO THE TERMINALS...AND
COVERAGE.

PREVIOUS DISCUSSION...
SEVERAL CONCERNS IN THE SHORT TERM REVOLVING AROUND A COUPLE DIFFERENT
WINDOWS OF OPPORTUNITY FOR SHRA/TSRA...AND WIND DIRECTION WITH AN
OUTFLOW BOUNDARY RACING SOUTH DOWN LAKE MICHIGAN.

RADAR AND SATELLITE TRENDS INDICATE THAT CONVECTIVE ACTIVITY AND
COVERAGE IS GENERALLY ON DOWNWARD TREND. SEEMS REASONABLE FOR THIS
TREND TO CONTINUE AS WE FALL BEHIND A WAVE THAT IS MOVING AWAY FROM
THE AREA ACROSS LAKE MICHIGAN. THE LOW LEVEL JET SETS UP WELL TO OUR
WEST AND WOULD SUPPORT ONGOING CONVECTION OVER NEBRASKA/WESTERN
IOWA...BUT NOT LOCALLY.

ON AVERAGE...IR IMAGERY SHOWS WARMING CLOUD TOPS OVER THE
AREA...WITH THE COOLEST CLOUD TOPS BECOMING MUCH MORE ISOLATED. THE
AREA CURRENTLY OVER THE CHICAGO TERMINALS HAS LOST MOST OF ITS
LIGHTNING...EXCEPT ON THE SOUTHERN MOST STORMS WHICH WILL NOT IMPACT
THE TERMINALS. EXPECT THAT BY THE TIME THE 06Z TAFS GO INTO EFFECT
THIS AREA WILL BE SOUTH OF ORD...AND SHOULD CLEAR MDW BY 0630Z. NEXT
AREA OF CONCERN IS AN AREA OVER NORTHWEST ILLINOIS. IF THIS AREA
HOLDS TOGETHER...EXPECT IT TO BE THROUGH THE CHICAGO TERMINALS BY
AROUND 09Z. GIVEN THE DOWNWARD TRENDS THOUGH DO NOT ANTICIPATE THIS
TO IMPACT BEYOND RFD WHICH SHOULD CLEAR BY 730Z.

TO OUR NORTH...AN OUTFLOW BOUNDARY IS EVIDENT ON RADAR IMAGERY
RACING SOUTH ALONG THE COAST OF LAKE MICHIGAN. THE CONVECTION TO
SUSTAIN THIS PUSH DOWN THE LAKE HAS SHIFTED EAST OF THE
BOUNDARY...WHICH IS STRUGGLING TO PUSH VERY FAR INLAND...BUT THERE
ARE CURRENTLY NORTHEAST GUSTS OF AROUND 20-25 KTS ASSOCIATED WITH
THE BOUNDARY. WINDS ARE EXPECTED TO SHIFT NORTHEAST AND INCREASE
SHARPLY...THEN SHOULD SETTLE DOWN SHORTLY THEREAFTER AND RETURN
CLOCKWISE BACK TO A MORE SOUTHERLY WIND...AND EVENTUALLY
SOUTHWEST. BASED ON THE CURRENT TRAJECTORY...IT WILL BE NEAR
ORD...MDW...AND GYY BY 630Z.

DID NOT MAKE ANY BIG CHANGES BEYOND THE FIRST 6 HOURS OF THE TAF.
FRONTAL TIMING STILL APPEARS TO BE AROUND 14Z WITH WINDS SHIFTING
TO NORTH...THEN NORTHEAST BEHIND THE FRONT. CANT COMPLETELY RULE
OUT ADDITIONAL THUNDERSTORMS DEVELOPING NEARBY TOMORROW AS WE
QUICKLY DEVELOP MODERATE INSTABILITY OVER THE AREA...BUT IT
APPEARS THE BEST FORCING WILL SHIFT SOUTH OF THE TERMINALS. SOME
MODEL SOUNDINGS CONTINUE TO INDICATE THE POTENTIAL FOR MVFR CIGS
TO DEVELOP RIGHT BEHIND THE FRONT FOR A COUPLE HOURS...THOUGH MOS
GUIDANCE INDICATES CONDITIONS WILL REMAIN VFR BEHIND THE FRONT.

BMD

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

* LOW CONFIDENCE IN TSRA TRENDS THROUGH THE MORNING.
* LOW CONFIDENCE IN MVFR CIGS BEHIND FRONT.

BMD

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

FRIDAY...VFR. NORTHEAST WINDS.

SATURDAY...VFR. EASTERLY WINDS.

SUNDAY THROUGH TUESDAY...VFR.

RC

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

$$

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

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION

NWS CHICAGO/ROMEOVILLE IL

 330 AM CDT THU AUG 22 2013

.DISCUSSION...
329 AM CDT

THE PRIMARY FORECAST CHALLENGES ARE CHANCES FOR STORMS TODAY AND
EARLY THIS EVE FOLLOWED BY THE HEAT...POTENTIALLY
PROLONGED...DURING NEXT WEEK.

THIS MORNING...A SOMEWHAT TRUBULENET...DISORGANIZED...AND EVEN
OVERTURNED ATMOSPHERE IS IN PLACE WITH ONE MCS HAVING GONE
THROUGH LATE LAST NIGHT ACROSS LAKE MI...WITH OUTFLOW STILL
PROGRESSING SOUTHEAST ACROSS THE CWA AS OF 315 AM. THIS IS
TRIGGERING A FEW STORMS THOUGH NOTHING ROBUST. FURTHER WEST AN MCS
EVOLVING EASTWARD ACROSS NORTHERN IA ALONG THE FRONTAL
BOUNDARY...WHICH IS VERY DIFFUSE EARLY TODAY...LOOKS TO WORK
EASTWARD WITHIN THE INSTABILITY MAXIMUM THROUGH THE MORNING. IN
ADVANCE OF THIS...NEAR THE BOUNDARY...THERE HAVE BEEN SOME
ISOLATED STORMS WITHIN THE HIGH PWAT AIR AND GENTLE WARM AIR
ADVECTION BUMPING UP AGAINST THE FRONT. SO ALL OF THIS LIKELY WILL
RESULT IN CONTINUED ISOLATED TO SCATTERED STORM GENERATION THIS
MORNING.

THIS AFTERNOON AND EVENING...WHILE THE IA MCS IS LIKELY TO BEGIN
DECAYING SOME LATER THIS MORNING GIVEN LIMITED DEEP LAYER
SHEAR...REMNANTS OF WHAT IS LEFT ALONG WITH A FORECAST
CONVECTIVELY ENHANCED WAVE BY THE RAP WILL MOVE INTO THE WESTERN
CWA LATE THIS MORNING/EARLY THIS AFTERNOON. THE POTENTIAL FOR THIS
TO RE-INSTIGATE STORMS IS CERTAINLY THERE WITH THE UNSTABLE AIR
MASS STILL IN PLACE AND NOT EXPECTED TO VACATE UNTIL THIS EVE DUE
TO THE SLOW COOL FRONTAL APPROACH FROM THE NORTH. MLCAPE VALUES
OF 1500-3000 J/KG ARE FORECAST BY THE NAM TO BUILD ACROSS THE
WESTERN AND SOUTHERN CWA...BASICALLY IN THOSE AREAS AWAY FROM THE
STABILIZING ONSHORE COMPONENT OFF THE LAKE. GIVEN LITTLE
INHIBITION THE TRIGGER OF THIS IMPULSE/MCV COULD BE ENOUGH TO
SPARK STORMS AND THE SUITE OF CONVECTIVE ALLOWING GUIDANCE HAS
MEMBERS THAT DO JUST THAT. SO HAVE INCREASED POPS SOME INCLUDING
HOLDING ONTO THEM LONGER. COULD CONCEIVABLY SEE SOME STORMS LINGER
INTO THE EVE...NAMELY SOUTH OF I-80. WITH LIMITED UPPER FORCING
AND DYNAMICS THE POTENTIAL FOR ORGANIZATION TOWARD ROBUST STORMS
REMAINS PRIMARILY LOW...THOUGH A FEW ISOLATED NEAR TO SEVERE
STORMS MAY DEVELOP. TEMPERATURES TODAY LOOK TO PEAK IN THE MID 80S
IN THOSE AREAS AWAY FROM THE LAKE WHERE AN ONSHORE COMPONENT WILL
INCREASE THIS AFTERNOON. HIGHS LAKESIDE LOOK TO BE IN THE UPPER
70S.

QUIET WEATHER IS EXPECTED FRI AND SAT WITH HIGHS AROUND NORMAL.
DEW POINTS IN THE 40S STILL LOOK PLAUSIBLE FRI AFTERNOON FOR
SEVERAL AREAS. FRI NIGHT LOOKS CLEAR AND CALM WITH HIGH
CONFIDENCE SO CONTINUE TO ADVERTISE LOWER TO MID 50S IN MOST
OUTLYING AREAS.

NEXT WEEK IS THE FINAL WEEK OF METEOROLOGICAL SUMMER AND IT IS
SHAPING UP TO BE EVERY BIT SUMMER...AT LEAST THE FIRST HALF OF
IT BUT POSSIBLY MUCH OF IT. WITH THE CURRENT TROUGH OVER CANADA
ONLY GIVING A GLANCING BLOW...THE RIDGE BUILDS BACK NORTHWARD
ACROSS THE CENTRAL TO EASTERN PARTS OF THE COUNTRY BY LATE IN THE
WEEKEND. DPROG/DTS FROM BOTH THE EC AND GFS HAVE INDICATED A
FURTHER NORTH 500MB RIDGE CENTER IN THE PAST 24 HOURS...AND THIS
HAS RESULTED IN A WARMING GUIDANCE TREND. THE 594DM RIDGE
PLACEMENT JUST TO THE WEST...MODEST AND WARM SW/WSW 850-925MB
FLOW...AND A DRY COLUMN IS A PATTERN CONDUCIVE FOR WIDESPREAD
LOWER-MID 90S MON AND TUE WITH THE 90 THRESHOLD LIKELY REACHED IN
PLACES ON SUN. THE JET IS ADVERTISED TO BE ACTIVE ON THE NORTH SIDE
OF THIS WITH BROAD LOW PRESSURE ACROSS THE HIGH PLAINS LIKELY
RESULTING IN MULTIPLE MCS DEVELOPMENT IF THIS PATTERN IS CORRECT.
AT THIS TIME...THESE ARE EXPECTED TO REMAIN NORTH BUT DEPENDING ON
FREQUENCY OF THEM LIKELY WILL DICTATE HOW FAR AND QUICKLY SOUTH
THE SURFACE BOUNDARY ADVANCES. WITH NO REAL DEW POINT SCOURING TO
OUR SOUTH FROM OUR CURRENT BOUNDARY...THESE SHOULD REBOUND TO AT
LEAST THE UPPER 60S BY MON AND HOLD TO SLIGHTLY INCREASE AS LONG
AS THE HEAT PERSISTS. BY TUE THIS RESULTS IN FORECAST HEAT INDICES
AT 100 TO 105 IN SOME PLACES /NOT CHICAGO AT THIS TIME/. WHILE
THIS PERIOD IS STILL NUMEROUS DAYS OUT...THERE SEEM TO BE A
LIMITED SET OF FACTORS PRIOR TO WED THAT COULD REALLY BOTCH UP THE
HEAT GIVEN THE AMPLITUDE OF THE RIDGE. WILL CONTINUE TO HIGHLIGHT
IN THE HWO.

MTF

&&

.AVIATION...

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

* CONVECTIVE TRENDS OVER THE NEXT SEVERAL HOURS.
* TEMPORARY WIND SHIFT TO THE NORTHEAST WITH WINDS GUSTING TO
  AROUND 20 KT FOR A SHORT PERIOD.
* WIND TRENDS OVERNIGHT BEHIND OUTFLOW BOUNDARY...AND SHIFTING TO
  NORTH ONCE AGAIN THURSDAY MORNING WITH A COLD FRONT.
* POTENTIAL FOR MVFR CIGS BEHIND THE FRONT.

BMD

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

SEVERAL CONCERNS IN THE SHORT TERM REVOLVING AROUND A COUPLE DIFFERENT
WINDOWS OF OPPORTUNITY FOR SHRA/TSRA...AND WIND DIRECTION WITH AN
OUTFLOW BOUNDARY RACING SOUTH DOWN LAKE MICHIGAN.

RADAR AND SATELLITE TRENDS INDICATE THAT CONVECTIVE ACTIVITY AND
COVERAGE IS GENERALLY ON DOWNWARD TREND. SEEMS REASONABLE FOR THIS
TREND TO CONTINUE AS WE FALL BEHIND A WAVE THAT IS MOVING AWAY FROM
THE AREA ACROSS LAKE MICHIGAN. THE LOW LEVEL JET SETS UP WELL TO OUR
WEST AND WOULD SUPPORT ONGOING CONVECTION OVER NEBRASKA/WESTERN
IOWA...BUT NOT LOCALLY.

ON AVERAGE...IR IMAGERY SHOWS WARMING CLOUD TOPS OVER THE
AREA...WITH THE COOLEST CLOUD TOPS BECOMING MUCH MORE ISOLATED. THE
AREA CURRENTLY OVER THE CHICAGO TERMINALS HAS LOST MOST OF ITS
LIGHTNING...EXCEPT ON THE SOUTHERN MOST STORMS WHICH WILL NOT IMPACT
THE TERMINALS. EXPECT THAT BY THE TIME THE 06Z TAFS GO INTO EFFECT
THIS AREA WILL BE SOUTH OF ORD...AND SHOULD CLEAR MDW BY 0630Z. NEXT
AREA OF CONCERN IS AN AREA OVER NORTHWEST ILLINOIS. IF THIS AREA
HOLDS TOGETHER...EXPECT IT TO BE THROUGH THE CHICAGO TERMINALS BY
AROUND 09Z. GIVEN THE DOWNWARD TRENDS THOUGH DO NOT ANTICIPATE THIS
TO IMPACT BEYOND RFD WHICH SHOULD CLEAR BY 730Z.

TO OUR NORTH...AN OUTFLOW BOUNDARY IS EVIDENT ON RADAR IMAGERY
RACING SOUTH ALONG THE COAST OF LAKE MICHIGAN. THE CONVECTION TO
SUSTAIN THIS PUSH DOWN THE LAKE HAS SHIFTED EAST OF THE
BOUNDARY...WHICH IS STRUGGLING TO PUSH VERY FAR INLAND...BUT THERE
ARE CURRENTLY NORTHEAST GUSTS OF AROUND 20-25 KTS ASSOCIATED WITH
THE BOUNDARY. WINDS ARE EXPECTED TO SHIFT NORTHEAST AND INCREASE
SHARPLY...THEN SHOULD SETTLE DOWN SHORTLY THEREAFTER AND RETURN
CLOCKWISE BACK TO A MORE SOUTHERLY WIND...AND EVENTUALLY
SOUTHWEST. BASED ON THE CURRENT TRAJECTORY...IT WILL BE NEAR
ORD...MDW...AND GYY BY 630Z.

DID NOT MAKE ANY BIG CHANGES BEYOND THE FIRST 6 HOURS OF THE TAF.
FRONTAL TIMING STILL APPEARS TO BE AROUND 14Z WITH WINDS SHIFTING
TO NORTH...THEN NORTHEAST BEHIND THE FRONT. CANT COMPLETELY RULE
OUT ADDITIONAL THUNDERSTORMS DEVELOPING NEARBY TOMORROW AS WE
QUICKLY DEVELOP MODERATE INSTABILITY OVER THE AREA...BUT IT
APPEARS THE BEST FORCING WILL SHIFT SOUTH OF THE TERMINALS. SOME
MODEL SOUNDINGS CONTINUE TO INDICATE THE POTENTIAL FOR MVFR CIGS
TO DEVELOP RIGHT BEHIND THE FRONT FOR A COUPLE HOURS...THOUGH MOS
GUIDANCE INDICATES CONDITIONS WILL REMAIN VFR BEHIND THE FRONT.

BMD

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

* MEDIUM CONFIDENCE THAT TSRA WILL NOT IMPACT THE TERMINALS THE
  REMAINDER OF TONIGHT AND TOMORROW.
* MEDIUM CONFIDENCE IN WIND TRENDS WITH A SHIFT TO
  NORTHEAST...VEERING BACK TO SOUTHWEST OVERNIGHT. MEDIUM TO HIGH CONFIDENCE
  IN FROPA TIMING THURSDAY MORNING.
* LOW CONFIDENCE IN MVFR CIGS BEHIND FRONT.

BMD

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

FRIDAY...VFR. NORTHEAST WINDS.

SATURDAY...VFR. EASTERLY WINDS.

SUNDAY THROUGH TUESDAY...VFR.

RC

&&

.MARINE...
250 AM CDT

LOW PRESSURE OF 29.1 INCHES LIES OVER FAR NORTHERN QUEBEC WITH A
COLD FRONT SAGGING TO THE SOUTHWEST ACROSS THE UPPER PENINSULA OF
MICHIGAN AND INTO CENTRAL WISCONSIN. THIS FRONT WILL CONTINUE TO
MOVE SOUTH ACROSS LAKE MICHIGAN THIS MORNING. THE FRONT SHOULD BE
SOUTH OF LAKE MICHIGAN THIS AFTERNOON AS HIGH PRESSURE OF 30.2
INCHES BUILDS ACROSS THE UPPER MIDWEST. THE HIGH WILL SHIFT EAST
OVER LAKE MICHIGAN ON FRIDAY...THEN OVER THE EASTERN LAKES
SATURDAY. A BROAD AREA OF LOW PRESSURE AVERAGING 29.7 INCHES WILL
DEVELOP OVER THE NORTHERN PLAINS AND CANADIAN PRAIRIES SUNDAY AND
MONDAY...AND SLOWLY SHIFT EAST ACROSS THE GREAT LAKES THROUGH
MIDWEEK.

BMD

&&

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

$$

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

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







AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 644 AM EDT THU AUG 22 2013

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

&&

.SYNOPSIS...
ISSUED AT 342 AM EDT THU AUG 22 2013

A COLD FRONT WILL TRACK THROUGH CENTRAL INDIANA TODAY AND TONIGHT
AND BRING SCATTERED THUNDERSTORMS TO CENTRAL INDIANA. HIGH PRESSURE
WILL BUILD ACROSS THE GREAT LAKES IN WAKE OF THE FRONTAL
PASSAGE...WITH DRY SEASONABLE CONDITIONS FRIDAY AND SATURDAY. THE
EXPANSION OF A BROAD UPPER RIDGE WILL SIGNAL THE BEGINNING OF A
WARMING TREND ON SUNDAY...WITH HOT WEATHER EXPECTED TO PERSIST FOR
MUCH OF NEXT WEEK.

&&

.NEAR TERM /TODAY/...
ISSUED AT 342 AM EDT THU AUG 22 2013

SCATTERED CONVECTION CONTINUES TO DEVELOP EARLY THIS MORNING AHEAD
OF WEAKENING STORM COMPLEX OVER LOWER MICHIGAN AND NORTHERN INDIANA.
HIGH CLOUDS ASSOCIATED WITH THE STORMS HAVE QUICKLY ENCOMPASSED A
GOOD PORTION OF THE FORECAST AREA ALREADY. TEMPS WERE PREDOMINANTLY
IN THE 60S AS OF 07Z.

BULK OF THE MODEL GUIDANCE LARGELY STRUGGLING WITH CURRENT
CONDITIONS AND SPECIFICALLY WITH THE AFOREMENTIONED COMPLEX TO THE
NORTH. CONVECTION IS WEAKENING AND DIMINISHING IN COVERAGE AS
EXPECTED WITH IT MOVING INTO A LESS FAVORABLE ENVIRONMENT OVER THE
FORECAST AREA. HRRR BEGINNING TO CATCH ON TO THE FASTER ARRIVAL OF
CONVECTION...AND MOST RECENT DATA SUGGESTIVE OF SCATTERED CONVECTION
IN A PROGRESSIVELY WEAKENED STATE MIGRATING INTO NORTHERN COUNTIES
THROUGH DAYBREAK. BEST COVERAGE TO RAINFALL SHOULD IMPACT NORTHEAST
COUNTIES OVER THE NEXT SEVERAL HOURS WITH PRECIP MORE SCATTERED
FURTHER WEST. HAVE BUMPED UP POPS THROUGH MID MORNING OVER THE
NORTHERN HALF OF THE FORECAST AREA FROM PREVIOUS FORECAST AS A
RESULT.

LOWER CONFIDENCE IN POTENTIAL CONVECTIVE COVERAGE AS THE DAY
PROGRESSES. STRONGER FORCING ALOFT MOVING INTO THE EASTERN GREAT
LAKES AND ANTICIPATE MUCH OF THE CONVECTION WILL EVENTUALLY END UP
TO THE EAST OF THE REGION IN CLOSER PROXIMITY TO THE BETTER FORCING.
CONVECTIVE COVERAGE FOR THE AFTERNOON WILL DEPEND ON HOW QUICKLY
CLOUD DEBRIS DIMINISHES AND THE AMOUNT OF INSTABILITY OVER THE
REGION LATER TODAY. MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT DURING
THE AFTERNOON WILL BE FORCING ASSOCIATED WITH THE FRONT AND
AVAILABLE INSTABILITY. IN ADDITION...SHORTWAVE ALOFT ASSOCIATED WITH
CONVECTIVE COMPLEX CURRENTLY OVER THE MISSOURI VALLEY WILL TRACK
INTO THE REGION BY LATE AFTERNOON AND MAY AID IN ADDITIONAL
CONVECTIVE DEVELOPMENT. WILL CONTINUE WITH 40-50 POPS DURING THE
AFTERNOON.

TEMPS...DESPITE PRESENCE OF ADDITIONAL HIGH CLOUDS THIS MORNING...
RECENT TREND HAS BEEN FOR TEMPS TO MAX OUT NEAR THE HIGH END OF
GUIDANCE AND SEE NO REASON TO DEVIATE FROM PERSISTENCE TODAY EVEN
WITH A GREATER THREAT FOR STORMS. WILL LEAN CLOSE TO MAV GUIDANCE.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 342 AM EDT THU AUG 22 2013

FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TONIGHT AND TEMPS
THROUGHOUT THE SHORT TERM.

BULK OF SCATTERED CONVECTION LIKELY TO BE FOCUSED ALONG AND SOUTH OF
I-70 BY THIS EVENING AS THE INCREASINGLY DIFFUSE FRONTAL BOUNDARY
PROGRESSES SOUTH. WILL MAINTAIN HIGHEST POPS OVER SOUTHERN COUNTIES
AND PREDOMINANTLY DURING THE EVENING...WITH PRECIP CHANCES ENDING
FROM THE NORTH AFTER MIDNIGHT AS THE FRONT CONTINUES MOVING SOUTH
INTO THE TENNESSEE VALLEY. HIGH PRESSURE WILL MOVE ACROSS THE
GREAT LAKES LATE TONIGHT WITH DRIER AIR ADVECTING INTO THE REGION
FROM THE NORTH. DEEPER MOISTURE WILL BE PUSHED TO THE SOUTH WITH
PRECIP LIKELY TO BE COMPLETELY OUT OF SOUTHERN COUNTIES BY 12Z
FRIDAY.

THE HIGH WILL TRACK THROUGH THE GREAT LAKES FRIDAY WITH NORTHEAST
WINDS CONTINUING TO BRING DRIER AIR AND SUBSIDENCE ALOFT INTO THE
REGION FROM THE NORTH. PRESENCE OF COLD ADVECTION IN THE WAKE OF THE
FRONTAL BOUNDARY WILL ENABLE SOME CU DEVELOPMENT THROUGH THE
AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE FORECAST AREA
WHERE LOW LEVEL MOISTURE WILL BE MORE PREVALENT. CU WILL DIMINISH
TOWARDS SUNSET WITH SKIES BECOMING MAINLY CLEAR AS EVEN DRIER AIR
BUILDS IN FROM THE NORTHEAST. DRY AND SEASONABLE CONDITIONS CAN BE
EXPECTED FOR THE REMAINDER OF THE SHORT TERM AS THE HIGH CENTERS
ACROSS NEW ENGLAND AND THE MID ATLANTIC. PREDOMINANT EASTERLY FLOW
WILL CONTINUE TO PUMP DRY AIR INTO CENTRAL INDIANA. MODEL SOUNDINGS
SUGGESTIVE OF MAINLY SUNNY CONDITIONS SATURDAY WITH LITTLE TO NO CU
DEVELOPMENT ANTICIPATED.

TEMPS...LOW LEVEL THERMALS REMAIN SUPPORTIVE OF WARMER MAVMOS
GUIDANCE AND WILL CONTINUE TO TREND HIGH TEMPS TOWARDS THE MAV.
RECENT DRY STRETCH ALSO WOULD SUPPORT WARMER TEMPS WITH HIGHS BOTH
FRIDAY AND SATURDAY EXPECTED TO BE IN THE LOW/MID 80S FOR MUCH OF
THE REGION. POTENTIAL FOR NEAR IDEAL RADIATIONAL COOLING CONDITIONS
BOTH FRIDAY AND SATURDAY NIGHTS WITH MAINLY CLEAR SKIES AND LIGHT
WINDS. SHOULD BE A GOOD SETUP FOR A RURAL-URBAN SPLIT IN TEMPS AS
OUTLYING LOCALES DROP INTO THE 50S.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 244 AM EDT THU AUG 22 2013

MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE USED
FOR MOST FEATURES...UNLESS NOTED BELOW. FOCUS IS MAINLY ON
TEMPERATURES.

A LARGE UPPER HIGH WILL BUILD ACROSS THE CENTRAL USA DURING THE
EXTENDED...AND THIS HIGH WILL BE THE MAIN INFLUENCE ON CENTRAL
INDIANA WEATHER. TEMPERATURES WILL WARM AS THE HIGH BUILDS IN AND
REMAINS IN CONTROL...SO HIGHS WARMING INTO THE 90S LOOK GOOD. BUMPED
UP ALLBLEND A BIT ON SOME DAYS AS IT SEEMED A LITTLE TOO COOL GIVEN
THE EXPECTED CONDITIONS.

REMOVED ALLBLEND/S CHANCES FOR RAIN THROUGH THE PERIOD. AT THE
MOMENT IT LOOKS LIKE ANY RING OF FIRE THUNDERSTORMS SHOULD REMAIN
OFF TO THE NORTH AND EAST...ESPECIALLY GIVEN THAT 700MB TEMPERATURES
WILL EXCEED 10C AND SHOULD CAP THINGS THROUGH THE PERIOD. OF COURSE
CANNOT ABSOLUTELY RULE OUT A POP UP STORM IN THE AFTERNOON...BUT
ODDS ARE TOO LOW TO MENTION AT THIS TIME.

&&

.AVIATION /DISCUSSION FOR THE 22/1200Z TAF ISSUANCE/...

ISSUED AT 644 AM EDT THU AUG 22 2013

OUTSIDE OF ANY PATCHY FOG EARLY AND OUTSIDE OF CONVECTION
ANYTIME...EXPECT VFR CONDITIONS.

CIRRUS SHIELD HAS HELPED KEEP FOG AT BAY THIS MORNING. FOCUS IS THEN
ON SCATTERED CONVECTION MOVING INTO THE AREA. CONVECTION SHOULD
WEAKEN SOME THIS MORNING AS TYPICALLY HAPPENS THIS TIME OF DAY. THUS
FEEL THAT ONLY VCSH SHOULD COVER IT MOST SITES. DID GO VCTS AT KLAF
AS THAT STATION IS CLOSEST TO CURRENT TSRA.

AS A COLD FRONT MOVES INTO CENTRAL INDIANA TODAY ADDITIONAL
SCATTERED CONVECTION SHOULD DEVELOP. THERE IS UNCERTAINTY THOUGH ON
HOW THEY WILL DEVELOP GIVEN LINGERING CLOUD COVER FROM THIS
MORNING/S CONVECTION. THUS CONTINUED WITH VCTS THIS AFTERNOON. LATER
UPDATES WILL BE ABLE TO REFINE FORECASTS.

FRONT WILL SINK SOUTH OF THE  AREA THIS EVENING ENDING THE
CONVECTION. CEILINGS SHOULD REMAIN VFR.


&&

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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS






AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 419 AM EDT THU AUG 22 2013

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

&&

.SYNOPSIS...
ISSUED AT 342 AM EDT THU AUG 22 2013

A COLD FRONT WILL TRACK THROUGH CENTRAL INDIANA TODAY AND TONIGHT
AND BRING SCATTERED THUNDERSTORMS TO CENTRAL INDIANA. HIGH PRESSURE
WILL BUILD ACROSS THE GREAT LAKES IN WAKE OF THE FRONTAL
PASSAGE...WITH DRY SEASONABLE CONDITIONS FRIDAY AND SATURDAY. THE
EXPANSION OF A BROAD UPPER RIDGE WILL SIGNAL THE BEGINNING OF A
WARMING TREND ON SUNDAY...WITH HOT WEATHER EXPECTED TO PERSIST FOR
MUCH OF NEXT WEEK.

&&

.NEAR TERM /TODAY/...
ISSUED AT 342 AM EDT THU AUG 22 2013

SCATTERED CONVECTION CONTINUES TO DEVELOP EARLY THIS MORNING AHEAD
OF WEAKENING STORM COMPLEX OVER LOWER MICHIGAN AND NORTHERN INDIANA.
HIGH CLOUDS ASSOCIATED WITH THE STORMS HAVE QUICKLY ENCOMPASSED A
GOOD PORTION OF THE FORECAST AREA ALREADY. TEMPS WERE PREDOMINANTLY
IN THE 60S AS OF 07Z.

BULK OF THE MODEL GUIDANCE LARGELY STRUGGLING WITH CURRENT
CONDITIONS AND SPECIFICALLY WITH THE AFOREMENTIONED COMPLEX TO THE
NORTH. CONVECTION IS WEAKENING AND DIMINISHING IN COVERAGE AS
EXPECTED WITH IT MOVING INTO A LESS FAVORABLE ENVIRONMENT OVER THE
FORECAST AREA. HRRR BEGINNING TO CATCH ON TO THE FASTER ARRIVAL OF
CONVECTION...AND MOST RECENT DATA SUGGESTIVE OF SCATTERED CONVECTION
IN A PROGRESSIVELY WEAKENED STATE MIGRATING INTO NORTHERN COUNTIES
THROUGH DAYBREAK. BEST COVERAGE TO RAINFALL SHOULD IMPACT NORTHEAST
COUNTIES OVER THE NEXT SEVERAL HOURS WITH PRECIP MORE SCATTERED
FURTHER WEST. HAVE BUMPED UP POPS THROUGH MID MORNING OVER THE
NORTHERN HALF OF THE FORECAST AREA FROM PREVIOUS FORECAST AS A
RESULT.

LOWER CONFIDENCE IN POTENTIAL CONVECTIVE COVERAGE AS THE DAY
PROGRESSES. STRONGER FORCING ALOFT MOVING INTO THE EASTERN GREAT
LAKES AND ANTICIPATE MUCH OF THE CONVECTION WILL EVENTUALLY END UP
TO THE EAST OF THE REGION IN CLOSER PROXIMITY TO THE BETTER FORCING.
CONVECTIVE COVERAGE FOR THE AFTERNOON WILL DEPEND ON HOW QUICKLY
CLOUD DEBRIS DIMINISHES AND THE AMOUNT OF INSTABILITY OVER THE
REGION LATER TODAY. MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT DURING
THE AFTERNOON WILL BE FORCING ASSOCIATED WITH THE FRONT AND
AVAILABLE INSTABILITY. IN ADDITION...SHORTWAVE ALOFT ASSOCIATED WITH
CONVECTIVE COMPLEX CURRENTLY OVER THE MISSOURI VALLEY WILL TRACK
INTO THE REGION BY LATE AFTERNOON AND MAY AID IN ADDITIONAL
CONVECTIVE DEVELOPMENT. WILL CONTINUE WITH 40-50 POPS DURING THE
AFTERNOON.

TEMPS...DESPITE PRESENCE OF ADDITIONAL HIGH CLOUDS THIS MORNING...
RECENT TREND HAS BEEN FOR TEMPS TO MAX OUT NEAR THE HIGH END OF
GUIDANCE AND SEE NO REASON TO DEVIATE FROM PERSISTENCE TODAY EVEN
WITH A GREATER THREAT FOR STORMS. WILL LEAN CLOSE TO MAV GUIDANCE.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 342 AM EDT THU AUG 22 2013

FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TONIGHT AND TEMPS
THROUGHOUT THE SHORT TERM.

BULK OF SCATTERED CONVECTION LIKELY TO BE FOCUSED ALONG AND SOUTH OF
I-70 BY THIS EVENING AS THE INCREASINGLY DIFFUSE FRONTAL BOUNDARY
PROGRESSES SOUTH. WILL MAINTAIN HIGHEST POPS OVER SOUTHERN COUNTIES
AND PREDOMINANTLY DURING THE EVENING...WITH PRECIP CHANCES ENDING
FROM THE NORTH AFTER MIDNIGHT AS THE FRONT CONTINUES MOVING SOUTH
INTO THE TENNESSEE VALLEY. HIGH PRESSURE WILL MOVE ACROSS THE
GREAT LAKES LATE TONIGHT WITH DRIER AIR ADVECTING INTO THE REGION
FROM THE NORTH. DEEPER MOISTURE WILL BE PUSHED TO THE SOUTH WITH
PRECIP LIKELY TO BE COMPLETELY OUT OF SOUTHERN COUNTIES BY 12Z
FRIDAY.

THE HIGH WILL TRACK THROUGH THE GREAT LAKES FRIDAY WITH NORTHEAST
WINDS CONTINUING TO BRING DRIER AIR AND SUBSIDENCE ALOFT INTO THE
REGION FROM THE NORTH. PRESENCE OF COLD ADVECTION IN THE WAKE OF THE
FRONTAL BOUNDARY WILL ENABLE SOME CU DEVELOPMENT THROUGH THE
AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE FORECAST AREA
WHERE LOW LEVEL MOISTURE WILL BE MORE PREVALENT. CU WILL DIMINISH
TOWARDS SUNSET WITH SKIES BECOMING MAINLY CLEAR AS EVEN DRIER AIR
BUILDS IN FROM THE NORTHEAST. DRY AND SEASONABLE CONDITIONS CAN BE
EXPECTED FOR THE REMAINDER OF THE SHORT TERM AS THE HIGH CENTERS
ACROSS NEW ENGLAND AND THE MID ATLANTIC. PREDOMINANT EASTERLY FLOW
WILL CONTINUE TO PUMP DRY AIR INTO CENTRAL INDIANA. MODEL SOUNDINGS
SUGGESTIVE OF MAINLY SUNNY CONDITIONS SATURDAY WITH LITTLE TO NO CU
DEVELOPMENT ANTICIPATED.

TEMPS...LOW LEVEL THERMALS REMAIN SUPPORTIVE OF WARMER MAVMOS
GUIDANCE AND WILL CONTINUE TO TREND HIGH TEMPS TOWARDS THE MAV.
RECENT DRY STRETCH ALSO WOULD SUPPORT WARMER TEMPS WITH HIGHS BOTH
FRIDAY AND SATURDAY EXPECTED TO BE IN THE LOW/MID 80S FOR MUCH OF
THE REGION. POTENTIAL FOR NEAR IDEAL RADIATIONAL COOLING CONDITIONS
BOTH FRIDAY AND SATURDAY NIGHTS WITH MAINLY CLEAR SKIES AND LIGHT
WINDS. SHOULD BE A GOOD SETUP FOR A RURAL-URBAN SPLIT IN TEMPS AS
OUTLYING LOCALES DROP INTO THE 50S.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 244 AM EDT THU AUG 22 2013

MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE USED
FOR MOST FEATURES...UNLESS NOTED BELOW. FOCUS IS MAINLY ON
TEMPERATURES.

A LARGE UPPER HIGH WILL BUILD ACROSS THE CENTRAL USA DURING THE
EXTENDED...AND THIS HIGH WILL BE THE MAIN INFLUENCE ON CENTRAL
INDIANA WEATHER. TEMPERATURES WILL WARM AS THE HIGH BUILDS IN AND
REMAINS IN CONTROL...SO HIGHS WARMING INTO THE 90S LOOK GOOD. BUMPED
UP ALLBLEND A BIT ON SOME DAYS AS IT SEEMED A LITTLE TOO COOL GIVEN
THE EXPECTED CONDITIONS.

REMOVED ALLBLEND/S CHANCES FOR RAIN THROUGH THE PERIOD. AT THE
MOMENT IT LOOKS LIKE ANY RING OF FIRE THUNDERSTORMS SHOULD REMAIN
OFF TO THE NORTH AND EAST...ESPECIALLY GIVEN THAT 700MB TEMPERATURES
WILL EXCEED 10C AND SHOULD CAP THINGS THROUGH THE PERIOD. OF COURSE
CANNOT ABSOLUTELY RULE OUT A POP UP STORM IN THE AFTERNOON...BUT
ODDS ARE TOO LOW TO MENTION AT THIS TIME.

&&

.AVIATION /DISCUSSION FOR THE 22/09Z TAF UPDATE/...
ISSUED AT 419 AM EDT THU AUG 22 2013

CONVECTION IS WORKING ITS WAY SOUTH ACROSS NORTHERN PORTIONS OF
INDIANA AT THE MOMENT. CURRENT TRENDS ARE FOR THE BULK OF THE
RAINFALL TO REMAIN JUST NORTHEAST OF KIND...BUT SCATTERED CONVECTION
WILL STILL BE NEAR KIND BY 10Z. HAVE ADDED VCSH FOR SEVERAL HOURS
THIS MORNING. LIGHTNING IS DECREASING SO LEFT THUNDER OUT FOR NOW.

PREVIOUS DISCUSSION FOLLOWS...
FOG POSSIBLE AGAIN TONIGHT. EXCEPT FOR PERHAPS BMG IFR APPEARS
UNLIKELY...BUT THIS WAS THE CASE LAST NIGHT AND THE OUTLYING SITES
ALL DROPPED BELOW 1SM AT LEAST BRIEFLY. WILL FORECAST MVFR
VISIBILITIES WITH BCFG TO ACCOUNT FOR POSSIBLE BRIEF REDUCTIONS
LOWER THAN PREVAILING MVFR.

VFR WILL RETURN BY MID MORNING.

SCATTERED SHOWERS AND THUNDERSTORMS ARE TRYING TO WORK THEIR WAY
SOUTH THROUGH NORTHERN INDIANA. NOT SURE IF THESE WILL SURVIVE TO
THE TAF SITES...BUT WILL INTRODUCE A VCSH AT KLAF FOR NOW AND
CONTINUE TO MONITOR.

STORMS WILL BE AT LEAST A SMALL POSSIBILITY WITH COLD FRONT
APPROACHING LATER TODAY. PREVIOUS FORECASTS INSERTED PROB30 AND THIS
IS REASONABLE.

WINDS WILL BE 10KT OR BELOW THROUGHOUT THE PERIOD.

&&

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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...NIELD/50

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS






AREA FORECAST DISCUSSION

NWS INDIANAPOLIS IN

 342 AM EDT THU AUG 22 2013

.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.

&&

.SYNOPSIS...
ISSUED AT 342 AM EDT THU AUG 22 2013

A COLD FRONT WILL TRACK THROUGH CENTRAL INDIANA TODAY AND TONIGHT
AND BRING SCATTERED THUNDERSTORMS TO CENTRAL INDIANA. HIGH PRESSURE
WILL BUILD ACROSS THE GREAT LAKES IN WAKE OF THE FRONTAL
PASSAGE...WITH DRY SEASONABLE CONDITIONS FRIDAY AND SATURDAY. THE
EXPANSION OF A BROAD UPPER RIDGE WILL SIGNAL THE BEGINNING OF A
WARMING TREND ON SUNDAY...WITH HOT WEATHER EXPECTED TO PERSIST FOR
MUCH OF NEXT WEEK.

&&

.NEAR TERM /TODAY/...
ISSUED AT 342 AM EDT THU AUG 22 2013

SCATTERED CONVECTION CONTINUES TO DEVELOP EARLY THIS MORNING AHEAD
OF WEAKENING STORM COMPLEX OVER LOWER MICHIGAN AND NORTHERN INDIANA.
HIGH CLOUDS ASSOCIATED WITH THE STORMS HAVE QUICKLY ENCOMPASSED A
GOOD PORTION OF THE FORECAST AREA ALREADY. TEMPS WERE PREDOMINANTLY
IN THE 60S AS OF 07Z.

BULK OF THE MODEL GUIDANCE LARGELY STRUGGLING WITH CURRENT
CONDITIONS AND SPECIFICALLY WITH THE AFOREMENTIONED COMPLEX TO THE
NORTH. CONVECTION IS WEAKENING AND DIMINISHING IN COVERAGE AS
EXPECTED WITH IT MOVING INTO A LESS FAVORABLE ENVIRONMENT OVER THE
FORECAST AREA. HRRR BEGINNING TO CATCH ON TO THE FASTER ARRIVAL OF
CONVECTION...AND MOST RECENT DATA SUGGESTIVE OF SCATTERED CONVECTION
IN A PROGRESSIVELY WEAKENED STATE MIGRATING INTO NORTHERN COUNTIES
THROUGH DAYBREAK. BEST COVERAGE TO RAINFALL SHOULD IMPACT NORTHEAST
COUNTIES OVER THE NEXT SEVERAL HOURS WITH PRECIP MORE SCATTERED
FURTHER WEST. HAVE BUMPED UP POPS THROUGH MID MORNING OVER THE
NORTHERN HALF OF THE FORECAST AREA FROM PREVIOUS FORECAST AS A
RESULT.

LOWER CONFIDENCE IN POTENTIAL CONVECTIVE COVERAGE AS THE DAY
PROGRESSES. STRONGER FORCING ALOFT MOVING INTO THE EASTERN GREAT
LAKES AND ANTICIPATE MUCH OF THE CONVECTION WILL EVENTUALLY END UP
TO THE EAST OF THE REGION IN CLOSER PROXIMITY TO THE BETTER FORCING.
CONVECTIVE COVERAGE FOR THE AFTERNOON WILL DEPEND ON HOW QUICKLY
CLOUD DEBRIS DIMINISHES AND THE AMOUNT OF INSTABILITY OVER THE
REGION LATER TODAY. MAIN CATALYSTS FOR CONVECTIVE DEVELOPMENT DURING
THE AFTERNOON WILL BE FORCING ASSOCIATED WITH THE FRONT AND
AVAILABLE INSTABILITY. IN ADDITION...SHORTWAVE ALOFT ASSOCIATED WITH
CONVECTIVE COMPLEX CURRENTLY OVER THE MISSOURI VALLEY WILL TRACK
INTO THE REGION BY LATE AFTERNOON AND MAY AID IN ADDITIONAL
CONVECTIVE DEVELOPMENT. WILL CONTINUE WITH 40-50 POPS DURING THE
AFTERNOON.

TEMPS...DESPITE PRESENCE OF ADDITIONAL HIGH CLOUDS THIS MORNING...
RECENT TREND HAS BEEN FOR TEMPS TO MAX OUT NEAR THE HIGH END OF
GUIDANCE AND SEE NO REASON TO DEVIATE FROM PERSISTENCE TODAY EVEN
WITH A GREATER THREAT FOR STORMS. WILL LEAN CLOSE TO MAV GUIDANCE.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 342 AM EDT THU AUG 22 2013

FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TONIGHT AND TEMPS
THROUGHOUT THE SHORT TERM.

BULK OF SCATTERED CONVECTION LIKELY TO BE FOCUSED ALONG AND SOUTH OF
I-70 BY THIS EVENING AS THE INCREASINGLY DIFFUSE FRONTAL BOUNDARY
PROGRESSES SOUTH. WILL MAINTAIN HIGHEST POPS OVER SOUTHERN COUNTIES
AND PREDOMINANTLY DURING THE EVENING...WITH PRECIP CHANCES ENDING
FROM THE NORTH AFTER MIDNIGHT AS THE FRONT CONTINUES MOVING SOUTH
INTO THE TENNESSEE VALLEY. HIGH PRESSURE WILL MOVE ACROSS THE
GREAT LAKES LATE TONIGHT WITH DRIER AIR ADVECTING INTO THE REGION
FROM THE NORTH. DEEPER MOISTURE WILL BE PUSHED TO THE SOUTH WITH
PRECIP LIKELY TO BE COMPLETELY OUT OF SOUTHERN COUNTIES BY 12Z
FRIDAY.

THE HIGH WILL TRACK THROUGH THE GREAT LAKES FRIDAY WITH NORTHEAST
WINDS CONTINUING TO BRING DRIER AIR AND SUBSIDENCE ALOFT INTO THE
REGION FROM THE NORTH. PRESENCE OF COLD ADVECTION IN THE WAKE OF THE
FRONTAL BOUNDARY WILL ENABLE SOME CU DEVELOPMENT THROUGH THE
AFTERNOON...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE FORECAST AREA
WHERE LOW LEVEL MOISTURE WILL BE MORE PREVALENT. CU WILL DIMINISH
TOWARDS SUNSET WITH SKIES BECOMING MAINLY CLEAR AS EVEN DRIER AIR
BUILDS IN FROM THE NORTHEAST. DRY AND SEASONABLE CONDITIONS CAN BE
EXPECTED FOR THE REMAINDER OF THE SHORT TERM AS THE HIGH CENTERS
ACROSS NEW ENGLAND AND THE MID ATLANTIC. PREDOMINANT EASTERLY FLOW
WILL CONTINUE TO PUMP DRY AIR INTO CENTRAL INDIANA. MODEL SOUNDINGS
SUGGESTIVE OF MAINLY SUNNY CONDITIONS SATURDAY WITH LITTLE TO NO CU
DEVELOPMENT ANTICIPATED.

TEMPS...LOW LEVEL THERMALS REMAIN SUPPORTIVE OF WARMER MAVMOS
GUIDANCE AND WILL CONTINUE TO TREND HIGH TEMPS TOWARDS THE MAV.
RECENT DRY STRETCH ALSO WOULD SUPPORT WARMER TEMPS WITH HIGHS BOTH
FRIDAY AND SATURDAY EXPECTED TO BE IN THE LOW/MID 80S FOR MUCH OF
THE REGION. POTENTIAL FOR NEAR IDEAL RADIATIONAL COOLING CONDITIONS
BOTH FRIDAY AND SATURDAY NIGHTS WITH MAINLY CLEAR SKIES AND LIGHT
WINDS. SHOULD BE A GOOD SETUP FOR A RURAL-URBAN SPLIT IN TEMPS AS
OUTLYING LOCALES DROP INTO THE 50S.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 244 AM EDT THU AUG 22 2013

MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE USED
FOR MOST FEATURES...UNLESS NOTED BELOW. FOCUS IS MAINLY ON
TEMPERATURES.

A LARGE UPPER HIGH WILL BUILD ACROSS THE CENTRAL USA DURING THE
EXTENDED...AND THIS HIGH WILL BE THE MAIN INFLUENCE ON CENTRAL
INDIANA WEATHER. TEMPERATURES WILL WARM AS THE HIGH BUILDS IN AND
REMAINS IN CONTROL...SO HIGHS WARMING INTO THE 90S LOOK GOOD. BUMPED
UP ALLBLEND A BIT ON SOME DAYS AS IT SEEMED A LITTLE TOO COOL GIVEN
THE EXPECTED CONDITIONS.

REMOVED ALLBLEND/S CHANCES FOR RAIN THROUGH THE PERIOD. AT THE
MOMENT IT LOOKS LIKE ANY RING OF FIRE THUNDERSTORMS SHOULD REMAIN
OFF TO THE NORTH AND EAST...ESPECIALLY GIVEN THAT 700MB TEMPERATURES
WILL EXCEED 10C AND SHOULD CAP THINGS THROUGH THE PERIOD. OF COURSE
CANNOT ABSOLUTELY RULE OUT A POP UP STORM IN THE AFTERNOON...BUT
ODDS ARE TOO LOW TO MENTION AT THIS TIME.

&&

.AVIATION /DISCUSSION FOR THE 22/06Z TAFS/...
ISSUED AT 1256 AM EDT THU AUG 22 2013

FOG POSSIBLE AGAIN TONIGHT. EXCEPT FOR PERHAPS BMG IFR APPEARS
UNLIKELY...BUT THIS WAS THE CASE LAST NIGHT AND THE OUTLYING SITES
ALL DROPPED BELOW 1SM AT LEAST BRIEFLY. WILL FORECAST MVFR
VISIBILITIES WITH BCFG TO ACCOUNT FOR POSSIBLE BRIEF REDUCTIONS
LOWER THAN PREVAILING MVFR.

VFR WILL RETURN BY MID MORNING.

SCATTERED SHOWERS AND THUNDERSTORMS ARE TRYING TO WORK THEIR WAY
SOUTH THROUGH NORTHERN INDIANA. NOT SURE IF THESE WILL SURVIVE TO
THE TAF SITES...BUT WILL INTRODUCE A VCSH AT KLAF FOR NOW AND
CONTINUE TO MONITOR.

STORMS WILL BE AT LEAST A SMALL POSSIBILITY WITH COLD FRONT
APPROACHING LATER TODAY. PREVIOUS FORECASTS INSERTED PROB30 AND THIS
IS REASONABLE.

WINDS WILL BE 10KT OR BELOW THROUGHOUT THE PERIOD.

&&

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

&&

$$

SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...NIELD/50

VISIT US AT HTTP://WWW.WEATHER.GOV/IND

FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS








AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 111 PM CDT THU AUG 22 2013

.UPDATE...
ISSUED AT 104 PM CDT THU AUG 22 2013

DENSE CI/CS FROM THE MCS IS HOLDING TEMPERATURES DOWN ACROSS MUCH
OF THE AREA. AS A RESULT...MAX TEMPERATURES HAVE BEEN LOWERED
AGAIN. ISOLATED TO SCATTERED SHOWERS WILL PERSIST THROUGH THE
AFTERNOON HOURS. THE MCS TOOL SUGGESTS THE POSSIBILITY OF DIURNAL
CONVECTION DEVELOPING IN RETURN WAA ALOFT ACROSS THE NORTHERN
PARTS OF THE CWFA THAT SLOWLY SINKS SOUTH DURING THE EVENING HOURS.

ANY RAINFALL FROM THIS POINT ONWARD WILL BE VERY SPOTTY. MOST
AREAS WILL REMAIN DRY DURING THE AFTERNOON/EVENING.       ..08..

UPDATE ISSUED AT 951 AM CDT THU AUG 22 2013

THE MCS ALONG THE WI/IL BORDER IS STARTING TO DECAY. THE OUTFLOW
BOUNDARY FROM THIS MCS IS DOWN TO I-80 AND WILL DICTATE FUTURE
CONVECTIVE TRENDS.

THE FCST WAS UPDATED TO SHOW MAINLY DRY CONDITIONS ALONG/SOUTH OF
HWY 30. HOWEVER...SINCE THOSE GRIDS WERE DONE NEW CONVECTION HAS
DEVELOPED BETWEEN KALO AND KCID WITH SOME SHRA IN THE
KCID/KDBQ/KMLI TRIANGLE.

NO MODEL IS CURRENTLY HANDLING THE SITUATION VERY WELL. THUS
NOWCASTING TOOLS WILL BE USED HEAVILY. THE MCS TOOL WHEN APPLIED
TO THE CURRENT RAP TRENDS IS SUGGESTING A BULK OF THE AREA WILL
REMAIN DRY TODAY WITH PERHAPS ISOLATED TO SCATTERED CONVECTION
ONCE THE MCS DISSIPATES.                 ..08..

UPDATE ISSUED AT 646 AM CDT THU AUG 22 2013
I HAVE UPDATED POPS ONCE AGAIN...NOW TO SHARPEN THE CUT FROM
CATEGORICAL NORTH...THE SLIGHT CHANCE ALONG I-80. THIS EVENT
BECOME MORE CHAOTIC THIS AFTERNOON...AND LOW CHANCE POPS ARE
RETAINED FOR MOST OF THE CWA.
ERVIN

&&

.SYNOPSIS...
ISSUED AT 308 AM CDT THU AUG 22 2013

A SLOW MOVING COLD FRONT IS CURRENTLY POSITIONED FROM NORTHERN
NEBRASKA...THROUGH SOUTHERN MINNESOTA AS OF 2 AM. EARLIER...SURFACE
BASED STORMS HAD BEEN PRESENT ALONG THE FRONT FROM NORTH CENTRAL
IOWA THROUGH WISCONSIN...BUT THESE HAVE LONG SINCE DISSIPATED.
ELEVATED CONVECTION IS FOUND IN TWO ZONES...ONE JUST TO THE EAST
OVER NORTHERN ILLINOIS AND INDIANA...AND ANOTHER TO THE WEST. THE
CONVECTION TO THE WEST IS SUPPORTED BY A WEAK SHORT WAVE TROF...AND
IS MUCH MORE ORGANIZED. THIS WESTERN CLUSTER...OR AT LEAST THE SHORT
WAVE ASSOCIATED WITH IT...WILL BE ENTERING OUR CWA TOWARD 12Z TODAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT THU AUG 22 2013

WITH THE BOUNDARY OVER THE CWA THROUGH THIS EVENING...IT IS CERTAIN
THAT WHAT EVER CONVECTION MOVES FROM WEST TO EAST ALONG THE FRONT
WILL HIT SOME PORTION OF THE CWA. AS OF NOW...MODELS TAKE A MATURE
MCS EAST THROUGH THE NORTHERN HALF OF THE CWA. THIS SEEMS QUITE
POSSIBLE...BUT GIVEN OUR RECENT STRETCH OF DRY WEATHER...I WILL WAIT
UNTIL IT HOLDS TOGETHER THROUGH CENTRAL IOWA BEFORE GREATLY RAISING
POPS. THE ATMOSPHERE MODESTLY SUPPORTS MAINTENANCE OF THIS
CONVECTIVE CLUSTER TODAY...AND AN UPGRADE FROM LIKELY/CHANCE POPS TO
CATEGORICAL IS QUITE POSSIBLE PRIOR TO 5 AM...BUT AFTER OUR EARLY
MORNING FORECAST ISSUANCE AT 3 AM. AT THIS TIME...IT APPEARS
LOCATIONS GENERALLY ALONG AND NORTH OF HIGHWAY 30...POSSIBLY THROUGH
INTERSTATE 80 STAND TO SEE THE BEST CHANCE OF WIDESPREAD CONVECTION
THIS MORNING. OTHERWISE...WE WILL KEEP CHANCE POPS GOING ALL
AFTERNOON...AND THIS EVENING AS THE FRONTAL BOUNDARY IS OVERHEAD.
SOME ELEVATED CELLS ARE AGAIN POSSIBLE OVERNIGHT TONIGHT...BUT THESE
SHOULD GENERALLY BE UNORGANIZED...AND TIED TO THE SOUTHWESTERN CWA.

TEMPERATURES TODAY WILL HAVE TO DEAL WITH PLENTY OF CLOUDS AND
POSSIBLY WIDESPREAD RAINFALL...THUS LOWER 80S NORTH TO UPPER 80S
SOUTH SEEM THE SAFEST BET FOR HIGHS. TONIGHTS LOWS UNDER SOME CLOUD
COVER...ARE LIKELY TO BE A BIT WARMER THAN EARLIER FORECAST. FOR NOW
AM THINKING UPPER 50S NORTHEAST TO UPPER 60S SOUTHWEST.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 335 AM CDT THU AUG 22 2013

THE EXTENDED FORECAST IN A NUTSHELL...HOT...HUMID...AND DRY. THE
PERIOD WILL BE DOMINATED BY A BUILDING UPPER LEVEL RIDGE OVER THE
NATIONS MIDSECTION WHICH WILL STRENGTHEN INTO NEXT WEEK...RESULTING
IN DRY CONDITIONS...AND A POSSIBLY A PROLONGED HEAT WAVE. OTHER THAN
A VERY SLIGHT CHANCE OF POPS IN THE SW FOR FRI AS AN 850MB MOISTURE
LINGERS OVER THE AREA...THE EXTENDED LOOKS DRY.  HIGHS FRI WILL BE
IN THE LOWER 80S NORTH...TO UPPER 80S SOUTH.  SLIGHTLY WARMER TEMPS
ARE ON TAP FOR SAT...WITH READINGS IN THE MID 80S NE TO NEAR 90 SW.
WE THEN TURN UP THE BURNER FOR SUNDAY THROUGH WEDNESDAY...AS 850
TEMPS WARM INTO THE LOW-MID 20S...TRANSLATING TO HIGHS EACH DAY IN
THE LOWER TO MIDDLE 90S...WHICH MAY APPROACH RECORD LEVELS.
HUMIDITY LEVELS WILL ALSO INCREASE DURING THIS TIME...WITH DEW
POINTS IN THE UPPER 60S TO LOW 70S.  OVERNIGHT LOWS SUN THROUGH WED
WILL BE IN THE LOW-MID 70...ALSO POSSIBLE RECORD WARM LOWS.  DAYTIME
HEAT INDICES WILL BE IN THE MID 90S TO AROUND 100.  THE REAL HEAT
DOME IS STILL WEST OUT OVER THE PLAINS...INDICATING NO REAL SIGNS OF
THE HEAT WAVE BREAKING ANY TIME SOON. STILL TOO SOON TO ISSUE HEAT
HEADLINE PRODUCTS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 104 PM CDT THU AUG 22 2013

GENERALLY VFR WX WITH ISOLATED TO SCATTERED SHRA AND POSSIBLY A
TSRA WILL BE SEEN ACROSS EASTERN IOWA AND NORTHERN ILLINOIS
THROUGH 00Z/23. A BRIEF PERIOD OF MVFR CONDITIONS MAY BE SEEN IF A
SHRA OR TSRA AFFECTS A TAF SITE. AFT 00Z/23 MAINLY VFR WX WILL BE
SEEN AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES BUT POCKETS OF
MVFR CONDITIONS ARE POSSIBLE. KDBQ HAS A STRONG PROBABILITY OF
DVLPG IFR CONDITIONS PRIOR TO SUNRISE DUE TO WET GROUND AND LIGHT
WINDS. THE POTENTIAL DOES EXIST FOR LIFR/VLIFR CONDITIONS AT KDBQ.

&&

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

$$

UPDATE...08
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...14
AVIATION...08






AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 958 AM CDT THU AUG 22 2013

.UPDATE...
ISSUED AT 951 AM CDT THU AUG 22 2013

THE MCS ALONG THE WI/IL BORDER IS STARTING TO DECAY. THE OUTFLOW
BOUNDARY FROM THIS MCS IS DOWN TO I-80 AND WILL DICTATE FUTURE
CONVECTIVE TRENDS.

THE FCST WAS UPDATED TO SHOW MAINLY DRY CONDITIONS ALONG/SOUTH OF
HWY 30. HOWEVER...SINCE THOSE GRIDS WERE DONE NEW CONVECTION HAS
DEVELOPED BETWEEN KALO AND KCID WITH SOME SHRA IN THE
KCID/KDBQ/KMLI TRIANGLE.

NO MODEL IS CURRENTLY HANDLING THE SITUATION VERY WELL. THUS
NOWCASTING TOOLS WILL BE USED HEAVILY. THE MCS TOOL WHEN APPLIED
TO THE CURRENT RAP TRENDS IS SUGGESTING A BULK OF THE AREA WILL
REMAIN DRY TODAY WITH PERHAPS ISOLATED TO SCATTERED CONVECTION
ONCE THE MCS DISSIPATES.                 ..08..

UPDATE ISSUED AT 646 AM CDT THU AUG 22 2013
I HAVE UPDATED POPS ONCE AGAIN...NOW TO SHARPEN THE CUT FROM
CATEGORICAL NORTH...THE SLIGHT CHANCE ALONG I-80. THIS EVENT
BECOME MORE CHAOTIC THIS AFTERNOON...AND LOW CHANCE POPS ARE
RETAINED FOR MOST OF THE CWA.
ERVIN

&&

.SYNOPSIS...
ISSUED AT 308 AM CDT THU AUG 22 2013

A SLOW MOVING COLD FRONT IS CURRENTLY POSITIONED FROM NORTHERN
NEBRASKA...THROUGH SOUTHERN MINNESOTA AS OF 2 AM. EARLIER...SURFACE
BASED STORMS HAD BEEN PRESENT ALONG THE FRONT FROM NORTH CENTRAL
IOWA THROUGH WISCONSIN...BUT THESE HAVE LONG SINCE DISSIPATED.
ELEVATED CONVECTION IS FOUND IN TWO ZONES...ONE JUST TO THE EAST
OVER NORTHERN ILLINOIS AND INDIANA...AND ANOTHER TO THE WEST. THE
CONVECTION TO THE WEST IS SUPPORTED BY A WEAK SHORT WAVE TROF...AND
IS MUCH MORE ORGANIZED. THIS WESTERN CLUSTER...OR AT LEAST THE SHORT
WAVE ASSOCIATED WITH IT...WILL BE ENTERING OUR CWA TOWARD 12Z TODAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 308 AM CDT THU AUG 22 2013

WITH THE BOUNDARY OVER THE CWA THROUGH THIS EVENING...IT IS CERTAIN
THAT WHAT EVER CONVECTION MOVES FROM WEST TO EAST ALONG THE FRONT
WILL HIT SOME PORTION OF THE CWA. AS OF NOW...MODELS TAKE A MATURE
MCS EAST THROUGH THE NORTHERN HALF OF THE CWA. THIS SEEMS QUITE
POSSIBLE...BUT GIVEN OUR RECENT STRETCH OF DRY WEATHER...I WILL WAIT
UNTIL IT HOLDS TOGETHER THROUGH CENTRAL IOWA BEFORE GREATLY RAISING
POPS. THE ATMOSPHERE MODESTLY SUPPORTS MAINTENANCE OF THIS
CONVECTIVE CLUSTER TODAY...AND AN UPGRADE FROM LIKELY/CHANCE POPS TO
CATEGORICAL IS QUITE POSSIBLE PRIOR TO 5 AM...BUT AFTER OUR EARLY
MORNING FORECAST ISSUANCE AT 3 AM. AT THIS TIME...IT APPEARS
LOCATIONS GENERALLY ALONG AND NORTH OF HIGHWAY 30...POSSIBLY THROUGH
INTERSTATE 80 STAND TO SEE THE BEST CHANCE OF WIDESPREAD CONVECTION
THIS MORNING. OTHERWISE...WE WILL KEEP CHANCE POPS GOING ALL
AFTERNOON...AND THIS EVENING AS THE FRONTAL BOUNDARY IS OVERHEAD.
SOME ELEVATED CELLS ARE AGAIN POSSIBLE OVERNIGHT TONIGHT...BUT THESE
SHOULD GENERALLY BE UNORGANIZED...AND TIED TO THE SOUTHWESTERN CWA.

TEMPERATURES TODAY WILL HAVE TO DEAL WITH PLENTY OF CLOUDS AND
POSSIBLY WIDESPREAD RAINFALL...THUS LOWER 80S NORTH TO UPPER 80S
SOUTH SEEM THE SAFEST BET FOR HIGHS. TONIGHTS LOWS UNDER SOME CLOUD
COVER...ARE LIKELY TO BE A BIT WARMER THAN EARLIER FORECAST. FOR NOW
AM THINKING UPPER 50S NORTHEAST TO UPPER 60S SOUTHWEST.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 335 AM CDT THU AUG 22 2013

THE EXTENDED FORECAST IN A NUTSHELL...HOT...HUMID...AND DRY. THE
PERIOD WILL BE DOMINATED BY A BUILDING UPPER LEVEL RIDGE OVER THE
NATIONS MIDSECTION WHICH WILL STRENGTHEN INTO NEXT WEEK...RESULTING
IN DRY CONDITIONS...AND A POSSIBLY A PROLONGED HEAT WAVE. OTHER THAN
A VERY SLIGHT CHANCE OF POPS IN THE SW FOR FRI AS AN 850MB MOISTURE
LINGERS OVER THE AREA...THE EXTENDED LOOKS DRY.  HIGHS FRI WILL BE
IN THE LOWER 80S NORTH...TO UPPER 80S SOUTH.  SLIGHTLY WARMER TEMPS
ARE ON TAP FOR SAT...WITH READINGS IN THE MID 80S NE TO NEAR 90 SW.
WE THEN TURN UP THE BURNER FOR SUNDAY THROUGH WEDNESDAY...AS 850
TEMPS WARM INTO THE LOW-MID 20S...TRANSLATING TO HIGHS EACH DAY IN
THE LOWER TO MIDDLE 90S...WHICH MAY APPROACH RECORD LEVELS.
HUMIDITY LEVELS WILL ALSO INCREASE DURING THIS TIME...WITH DEW
POINTS IN THE UPPER 60S TO LOW 70S.  OVERNIGHT LOWS SUN THROUGH WED
WILL BE IN THE LOW-MID 70...ALSO POSSIBLE RECORD WARM LOWS.  DAYTIME
HEAT INDICES WILL BE IN THE MID 90S TO AROUND 100.  THE REAL HEAT
DOME IS STILL WEST OUT OVER THE PLAINS...INDICATING NO REAL SIGNS OF
THE HEAT WAVE BREAKING ANY TIME SOON. STILL TOO SOON TO ISSUE HEAT
HEADLINE PRODUCTS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM CDT THU AUG 22 2013

A PERIOD OF STRONG THUNDERSTORM ACTIVITY SHOULD AFFECT DBQ FROM
12Z TO 14Z THIS MORNING WITH HEAVY RAIN AND GUSTY WINDS.
OTHERWISE...SCATTERED TO ISOLATED SHOWERS OR STORMS REMAIN
POSSIBLE AT CID MLI AND BRL...BUT FROM HERE ON OUT IT LOOKS TOO
LIMITED TO INCLUDE IN ANY TAF BEYOND VICINITY SHOWERS. WINDS TODAY
WILL BE LIGHT SOUTH TO LIGHT NORTH...UNDER 8 KTS...AS A FRONT
DROPS SOUTH OVER THE AREA. BY TONIGHT...SKIES WILL CLEAR FROM
NORTH TO SOUTH...AND SOME PATCHY MVFR FOG COULD
DEVELOP...ESPECIALLY IN TERMINALS THAT SEE RAIN TODAY...AND AT
THIS POINT...THAT WOULD BE DBQ.
ERVIN


&&

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

$$

UPDATE...08
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...14
AVIATION...ERVIN







AREA FORECAST DISCUSSION

NWS QUAD CITIES IA IL

 1150 PM CDT WED AUG 21 2013

.UPDATE...
ISSUED AT 946 PM CDT WED AUG 21 2013

SURFACE AND 850 MB FRONTS TO PUSH THROUGH MUCH OF THE AREA OVER THE
NEXT 24 HRS. MOISTURE POOLING JUST AHEAD OF THESE BOUNDARIES IN
WEST TO EAST FASHION WITH SFC DEWPTS IN THE 70S AND LAYER PWATS
APPROACHING 2 INCHES. MEANWHILE...DISTURBANCE IN MONSOONAL
MOISTURE EMERGING INTO THE PLAINS FROM ROCKIES AND ON AN EASTERLY
COURSE AROUND PERIPHERY OF SOUTHERN PLAINS HEAT DOME. THESE
INGREDIENTS ARE ENCOURAGING FOR RAIN PROSPECTS NEXT 24 HRS. ALSO
ENCOURAGING TO SEE SOME PCPN ALREADY SNEAKING INTO FAR NORTH AND
EAST PORTIONS OF CWA... AND ANTICIPATE MORE DEVELOPMENT OVERNIGHT
ZIPPERING BACK TOWARD NE CONVECTION SLIDING E-THEN S/E THROUGH
THU AM PER CORFIDI VECTORS. WILL HAVE UPDATED GRIDS/ZFP OUT SOON.

&&

.SYNOPSIS...
ISSUED AT 314 PM CDT WED AUG 21 2013

12Z UA ANALYSIS HAS AN 850MB TROF RUNNING FROM WESTERN LAKE SUPERIOR
INTO WYOMING. AHEAD OF THIS TROF 850MB DEW POINTS WERE IN THE MID
TEENS FROM UPPER MICHIGAN INTO EASTERN NEBRASKA. SATELLITE/RADAR
TRENDS THROUGH MID AFTERNOON SHOW VERY LITTLE IN THE WAY OF DIURNAL
CLOUDS ACROSS THE AREA BUT CONVECTION HAS FIRED ALONG THE COLD FRONT
FROM NEAR KFSD INTO WESTERN WISCONSIN.

18Z SFC ANALYSIS HAS A WEAK LOW NEAR KFSD. THE FRONT RAN NORTHEAST
FROM THE LOW INTO WESTERN UPPER MICHIGAN. AROUND THE FRONTAL
BOUNDARY DEW POINTS WERE IN THE LOW 70S WITH 60S ACROSS THE
REMAINDER OF THE MIDWEST.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 314 PM CDT WED AUG 21 2013

THE CONVECTION THAT HAS DEVELOPED THIS AFTERNOON IS IN AN AREA OF
STEEP 850-700MB LAPSE RATES AND IN THE SLIGHTLY BETTER
FORCING/CONVERGENCE ASSOCIATED WITH THE FRONTAL ZONE. THE RAP TRENDS
KEEP MORE STABLE AIR ACROSS THE IMMEDIATE AREA THROUGH LATE
AFTERNOON SO ANY CONVECTION APPROACHING THE AREA WILL DISSIPATE.

THE MCS AND LIFT TOOLS SUGGEST ISOLATED TO POSSIBLY SCATTERED
CONVECTION ENTERING THE HWY 20 CORRIDOR DURING THE EARLY EVENING. BY
MID TO LATE EVENING NEW CONVECTION SHOULD DEVELOP AND BECOME LOOSELY
ORGANIZED FROM HWY 30 ON NORTH. BOUNDARIES FROM THIS CONVECTION
SHOULD ALLOW ISOLATED SHOWERS AND STORMS TO DEVELOP ALONG AND SOUTH
OF I-80 AFTER MIDNIGHT.

ON THURSDAY...LINGERING NOCTURNAL CONVECTION SHOULD BE OVER THE AREA
AS THE FRONT CONTINUES TO SLOWLY MOVE SOUTH THROUGH THE AREA.
DIFFERENTIAL HEATING WILL THEN ALLOW NEW CONVECTION TO DEVELOP
DURING THE LATE MORNING AND AFTERNOON HOURS. AS THE NEXT CANADIAN
HIGH BUILDS INTO THE GREAT LAKES...THE DRIER AIR WILL SLOWLY FORCE
THE CONVECTION SOUTH THURSDAY AFTERNOON WITH IT ONLY OVER THE
SOUTHWEST THIRD OF THE CWFA BY THURSDAY EVENING.    ..08..

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 314 PM CDT WED AUG 21 2013

AN UPPER RIDGE OVER THE WESTERN STATES IS PROGGED TO BUILD EAST AND
STRENGTHEN THROUGH THE MIDDLE OF NEXT WEEK...PROLONGING THE DRY
CONDITIONS AND BRINGING LATE SUMMER HEAT TO THE REGION.

ABOUT THE ONLY CHANCE OF RAIN WILL BE THE POTENTIAL FOR SOME
LINGERING SHRA/TSRA OVER THE SOUTHWEST THURSDAY NIGHT NEAR A
DECAYING FRONT OVER MISSOURI.  FORCING WILL NOT BE VERY STRONG GIVEN
THE WEAK FLOW NEAR THE FRONTAL ZONE AND WITH THE UPPER RIDGE
BUILDING INTO THE REGION...POPS WERE KEPT IN THE SLIGHT CHANCE
CATEGORY.

THE UPPER RIDGE CONTINUES TO BUILD INTO THE REGION WITH A
594DM-PLUS  H5 HIGH CENTERED OVER MO BY SUNDAY NIGHT AND REMAINING
IN PLACE THROUGH THE MIDDLE OF THE WEEK.  THE STRONGER MID LEVEL
FLOW WILL BE DIVERTED AROUND THE RIDGE WHICH WILL KEEP THE BETTER
FORCING WELL NORTH OF THE AREA. THE GFS AND  12Z ECMWF SHOW SOME QPF
OVER THE AREA BY NEXT WEDNESDAY OR WEDNESDAY NIGHT ASSOCIATED WITH
A SHORT WAVE AND FRONT MOVING THE THROUGH THE WESTERN GREAT LAKES
AND MISSISSIPPI VALLEY.  HOWEVER KEPT POPS OUT OF THE FORECAST FOR
NOW WITH MID LEVEL TEMPS  PROGGED TO BE AROUND 12C SUGGESTING THESE
FEATURES WILL BE FIGHTING A CAP.

SUMMERTIME HEAT WILL BE RETURNING TO THE REGION AS H8 TEMPS WARM
INTO THE LOW 20/S BY SUNDAY AND REMAIN THERE THROUGH MID WEEK.  THE
BLENDED GUIDANCE WAS WARMING HIGH TEMPERATURES TO AROUND 90 BUT
MIXING DOWN H8 TEMPS EARLY NEXT WEEK YIELDED HIGHS IN THE LOW TO MID
90S. FORECAST HIGHS WERE SKEWED TOWARD THE TEMPS DERIVED FROM MIXING
WHICH SEEM MORE REASONABLE. WITH THESE WARMER TEMPERATURES...AND
DEWPOINTS EXPECTED TO BE NEAR 70...WE WILL PROBABLY SEE HEAT INDICES
CLOSE TO 100 DURING THE HEAT OF THE DAY. AT THIS TIME IT DOESN/T
APPEAR THAT WE WILL BE CLOSE TO ANY RECORD HIGHS...AT LEAST THROUGH
THE 28TH. RECORDS DURING THIS TIME ARE NEAR OR ABOVE 100 AT THE
CLIMATE SITES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1123 PM CDT WED AUG 21 2013

FRONTAL ZONE TO SAG THROUGH MUCH OF THE AREA NEXT 24 HRS AND WILL
BE ACCOMPANIED BY CHC OF SHOWERS AND STORMS. BEST CHCS STILL
LOOK TO BE NORTH OF I-80 LATE TONIGHT THROUGH MIDDAY THU. MVFR TO
POSSIBLY IFR VSBYS EXIST WITH ANY STORMS. LIGHT WINDS AND
MOISTURE POOLING AHEAD OF FRONT WILL AID IN SOME FOG DEVELOPING
BETWEEN 09Z-14Z WITH VSBYS MAINLY 3-6SM ALTHOUGH CAN/T RULE OUT
IFR VSBYS AT KDBQ WHERE BETTER MOISTURE RESIDES.

&&

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

$$

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







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1030 AM MDT THU AUG 22 2013

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 248 AM MDT THU AUG 22 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW BROAD RIDGE STILL IN
PLACE ACROSS THE SOUTHERN PLAINS...WITH ACTIVE ZONAL FLOW ACROSS
THE NORTHERN PLAINS. SEVERAL SHORTWAVE TROUGHS ARE IN PLACE WITHIN
THE MEAN FLOW OVER CENTRAL NEBRASKA AND WESTERN WYOMING. AT THE
SURFACE A COLD FRONT HAS PUSHED SOUTH OVER OUR CWA AND IS
CURRENTLY EXTENDING FRONT NORTON TO CHEYENNE WELLS BEFORE TURNING
BACK TO THE NORTH ALONG THE THE FRONT RANGE IN COLORADO.

THUNDERSTORMS DEVELOPED OVERNIGHT AHEAD OF THIS FRONT IN THE FAR
EASTERN PART OF THE CWA...WITH SUPPORT FROM H85 50KT JET AND
STRONG THETA-E CONVERGENCE IN THE H85-H7 LAYER. SHORT RANGE
GUIDANCE SUPPORTS THIS ACTIVITY PULLING OFF THE EAST THROUGH
SUNRISE...HOWEVER LITTLE WILL CHANGE REGARDING INSTABILITY/FORCING
SO WILL NEED TO MONITOR/REEVALUATE IF I NEED TO KEEP POPS MENTION
BEYOND 15Z FOR THESE LOCATIONS. ADDITIONAL THUNDERSTORM IS
EXPECTED TO DEVELOP THIS AFTERNOON GENERALLY ALONG THE THE STALLED
FRONT...WITH ADDITIONAL FORCING IN THE LATE AFTERNOON THROUGH
EVENING ASSOCIATED WITH SHORTWAVE TROUGH PASSAGE IN NEBRASKA. WITH
FRONT OVER OUR CWA WE SHOULD SEE BETTER COVERAGE ALONG
FRONT. BETTER INSTABILITY GENERALLY TO THE NORTH OF THE FRONT
WHERE TD VALUES IN THE 60S WILL BE...SO I KEPT CHANCE POPS
GENERALLY OVER THE NW CWA. NAM/RAP BOTH SHOW SB/ML CAPE IN EXCESS
OF 2000 J/KG NORTH OF THIS FRONT WHICH COULD CERTAINLY SUPPORT
STRONG UPDRAFTS. SHEER ON THE OTHER HAND IS NOT QUITE AS
STRONG (0-6KM 20-25KT). THERE DOES APPEAR TO BE ENOUGH SUPPORT FOR
AN ELEVATED LARGE HAIL/STRONG WIND THREAT WITH THUNDERSTORMS THAT
DEVELOP.

AFTER TOMORROW NIGHT PRECIP CHANCES DECREASE SIGNIFICANTLY WITH
INCREASING CAP AND STRONGER SUBSIDENCE ASSOCIATED WITH BUILDING
RIDGE. THERE IS SOME INDICATION OF THUNDERSTORMS MOVING INTO THE
FAR NW PART OF THE CWA FRIDAY AFTERNOON/EVENING...SO I ADDED
SLIGHT CHANCE POPS. BY SATURDAY THE MEAN STORM TRACK WILL HAVE
SHIFTED FAR ENOUGH NORTH WITH STRONG CINH AND LARGE SCALE
SUBSIDENCE INHIBITING AFTERNOON/EVENING CHANCES.

TEMPS WILL DROP CLOSER TO SEASONAL NORMS TODAY BEHIND FRONT IN
THE UPPER 80S/LOW 90S. TH TREND WILL BE MUCH ABOVE NORMAL FRIDAY
AND SATURDAY WITH STRONG RIDGE (595DM) AND STRONG WAA ASSOCIATED
WITH SOUTHERLY FLOW EAST OF STRENGTHENING LEE TROUGH. HAVE TRENDED
TEMPS TOWARDS UPPER 90S BASED ON MIXING WED...AND MIGHT BE A FEW
DEGREES TOO COOL WITH TEMPS NEAR 100F NOT OUT OF THE QUESTION.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 248 AM MDT THU AUG 22 2013

FORECAST PATTERN FOR THE WEEKEND AND EARLY NEXT WEEK HAS CHANGED
LITTLE OVER THE PAST FEW DAYS. A STRONG UPPER-LEVEL RIDGE WILL BE
CENTERED OVER THE CENTRAL PLAINS FOR MUCH OF THE PERIOD...WITH THE
GEM AND ECMWF PLACING THE UPPER HIGH JUST EAST OF THE CENTRAL
PLAINS. WHILE THE RIDGE IS IN PLACE PRECIP CHANCES WILL BE NEAR-NIL
AS DISTURBANCES ROTATE AROUND THE RIDGE. TEMPS WILL BE WELL ABOVE
NORMAL WITH 850MB TEMPS IN THE LOW 30S C...TRANSLATING TO HIGHS IN
THE MID TO UPPER 90S. WOULD NOT BE SURPRISED TO SEE SOME SPOTS HIT
THE TRIPLE DIGITS MON OR TUES...THE HEAT PEAKING AROUND TUESDAY
BEFORE THE RIDGE SHIFTS A BIT FURTHER EAST INTO THE MIDDLE OF THE
WEEK. WINDS DURING THE PERIOD WILL BE PRETTY BREEZY OUT OF THE
SOUTH AT 15 TO 20 MPH DURING THE AFTERNOONS AS A NORTH-SOUTH
ORIENTED SURFACE TROUGH DEVELOPS IN EASTERN COLORADO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1030 AM MDT THU AUG 22 2013

FOR KGLD AND KMCK VFR EXPECTED THROUGH THE PERIOD. GUSTY POST
FRONTAL NORTHEAST WINDS OF 15-20KTS AT TAF ISSUANCE WILL GRADUALLY
VEER TO THE NORTHEAST AND EAST THROUGH THE REST OF THE DAY WITH
SPEEDS SLOWLY DECREASING. FOR TONIGHT WINDS WILL BE LIGHT. FOR
FRIDAY LIGHT WINDS BECOME SOUTHEAST AT 12-13KTS WITH GUSTS AROUND
20KTS (KGLD) TOWARD THE END OF THE TAF PERIOD. ONLY MID AND HIGH
CLOUDS EXPECTED. MAY SEE A FEW SHOWERS AND THUNDERSTORMS THIS
AFTERNOON INTO EARLY EVENING BUT COVERAGE SHOULD BE RATHER LIMITED
AND CONFIDENCE TOO LOW TO INCLUDE IN TAFS AT PRESENT TIME.

&&

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

$$

SHORT TERM...DR
LONG TERM...JJM
AVIATION...99







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 457 AM MDT THU AUG 22 2013

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 248 AM MDT THU AUG 22 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW BROAD RIDGE STILL IN
PLACE ACROSS THE SOUTHERN PLAINS...WITH ACTIVE ZONAL FLOW ACROSS
THE NORTHERN PLAINS. SEVERAL SHORTWAVE TROUGHS ARE IN PLACE WITHIN
THE MEAN FLOW OVER CENTRAL NEBRASKA AND WESTERN WYOMING. AT THE
SURFACE A COLD FRONT HAS PUSHED SOUTH OVER OUR CWA AND IS
CURRENTLY EXTENDING FRONT NORTON TO CHEYENNE WELLS BEFORE TURNING
BACK TO THE NORTH ALONG THE THE FRONT RANGE IN COLORADO.

THUNDERSTORMS DEVELOPED OVERNIGHT AHEAD OF THIS FRONT IN THE FAR
EASTERN PART OF THE CWA...WITH SUPPORT FROM H85 50KT JET AND
STRONG THETA-E CONVERGENCE IN THE H85-H7 LAYER. SHORT RANGE
GUIDANCE SUPPORTS THIS ACTIVITY PULLING OFF THE EAST THROUGH
SUNRISE...HOWEVER LITTLE WILL CHANGE REGARDING INSTABILITY/FORCING
SO WILL NEED TO MONITOR/REEVALUATE IF I NEED TO KEEP POPS MENTION
BEYOND 15Z FOR THESE LOCATIONS. ADDITIONAL THUNDERSTORM IS
EXPECTED TO DEVELOP THIS AFTERNOON GENERALLY ALONG THE THE STALLED
FRONT...WITH ADDITIONAL FORCING IN THE LATE AFTERNOON THROUGH
EVENING ASSOCIATED WITH SHORTWAVE TROUGH PASSAGE IN NEBRASKA. WITH
FRONT OVER OUR CWA WE SHOULD SEE BETTER COVERAGE ALONG
FRONT. BETTER INSTABILITY GENERALLY TO THE NORTH OF THE FRONT
WHERE TD VALUES IN THE 60S WILL BE...SO I KEPT CHANCE POPS
GENERALLY OVER THE NW CWA. NAM/RAP BOTH SHOW SB/ML CAPE IN EXCESS
OF 2000 J/KG NORTH OF THIS FRONT WHICH COULD CERTAINLY SUPPORT
STRONG UPDRAFTS. SHEER ON THE OTHER HAND IS NOT QUITE AS
STRONG (0-6KM 20-25KT). THERE DOES APPEAR TO BE ENOUGH SUPPORT FOR
AN ELEVATED LARGE HAIL/STRONG WIND THREAT WITH THUNDERSTORMS THAT
DEVELOP.

AFTER TOMORROW NIGHT PRECIP CHANCES DECREASE SIGNIFICANTLY WITH
INCREASING CAP AND STRONGER SUBSIDENCE ASSOCIATED WITH BUILDING
RIDGE. THERE IS SOME INDICATION OF THUNDERSTORMS MOVING INTO THE
FAR NW PART OF THE CWA FRIDAY AFTERNOON/EVENING...SO I ADDED
SLIGHT CHANCE POPS. BY SATURDAY THE MEAN STORM TRACK WILL HAVE
SHIFTED FAR ENOUGH NORTH WITH STRONG CINH AND LARGE SCALE
SUBSIDENCE INHIBITING AFTERNOON/EVENING CHANCES.

TEMPS WILL DROP CLOSER TO SEASONAL NORMS TODAY BEHIND FRONT IN
THE UPPER 80S/LOW 90S. TH TREND WILL BE MUCH ABOVE NORMAL FRIDAY
AND SATURDAY WITH STRONG RIDGE (595DM) AND STRONG WAA ASSOCIATED
WITH SOUTHERLY FLOW EAST OF STRENGTHENING LEE TROUGH. HAVE TRENDED
TEMPS TOWARDS UPPER 90S BASED ON MIXING WED...AND MIGHT BE A FEW
DEGREES TOO COOL WITH TEMPS NEAR 100F NOT OUT OF THE QUESTION.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 248 AM MDT THU AUG 22 2013

FORECAST PATTERN FOR THE WEEKEND AND EARLY NEXT WEEK HAS CHANGED
LITTLE OVER THE PAST FEW DAYS. A STRONG UPPER-LEVEL RIDGE WILL BE
CENTERED OVER THE CENTRAL PLAINS FOR MUCH OF THE PERIOD...WITH THE
GEM AND ECMWF PLACING THE UPPER HIGH JUST EAST OF THE CENTRAL
PLAINS. WHILE THE RIDGE IS IN PLACE PRECIP CHANCES WILL BE NEAR-NIL
AS DISTURBANCES ROTATE AROUND THE RIDGE. TEMPS WILL BE WELL ABOVE
NORMAL WITH 850MB TEMPS IN THE LOW 30S C...TRANSLATING TO HIGHS IN
THE MID TO UPPER 90S. WOULD NOT BE SURPRISED TO SEE SOME SPOTS HIT
THE TRIPLE DIGITS MON OR TUES...THE HEAT PEAKING AROUND TUESDAY
BEFORE THE RIDGE SHIFTS A BIT FURTHER EAST INTO THE MIDDLE OF THE
WEEK. WINDS DURING THE PERIOD WILL BE PRETTY BREEZY OUT OF THE
SOUTH AT 15 TO 20 MPH DURING THE AFTERNOONS AS A NORTH-SOUTH
ORIENTED SURFACE TROUGH DEVELOPS IN EASTERN COLORADO.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 457 AM MDT THU AUG 22 2013

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE TAF PERIOD AT
BOTH KGLD AND KMCK TERMINALS. PRIMARY AVIATION CONCERN IS
THUNDERSTORMS POSSIBLY DEVELOPING WITHIN THE VICINITY OF BOTH
TERMINALS THIS AFTERNOON/EVENING ALONG AND NORTH OF STALLED FRONT.
WHILE CONFIDENCE IS INCREASING IN ISOLATED-SCATTERED THUNDERSTORMS
INITIATING ACROSS NW KS AND SW NE...I AM NOT CONFIDENT IN COVERAGE
IN RELATION TO BOTH TERMINALS. FRONT POSITION SHOULD BE JUST
SOUTH...AND BEST UPPER LEVEL SUPPORT WILL BE WELL TO THE NORTH
LATE TONIGHT. WILL HOLD OFF ON ADDING VCTS GROUP THIS TAF
ISSUANCE. SUSTAINED WINDS SHOULD REMAIN BELOW 12KT AT BOTH
TERMINALS WITH WINDS SHIFTING TO THE SOUTH- SOUTHEAST BY THIS
EVENING AS FRONT BEGINS TO LIFT BACK TO THE NORTH.

&&

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

$$

SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 249 AM MDT THU AUG 22 2013

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 248 AM MDT THU AUG 22 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW BROAD RIDGE STILL IN
PLACE ACROSS THE SOUTHERN PLAINS...WITH ACTIVE ZONAL FLOW ACROSS
THE NORTHERN PLAINS. SEVERAL SHORTWAVE TROUGHS ARE IN PLACE WITHIN
THE MEAN FLOW OVER CENTRAL NEBRASKA AND WESTERN WYOMING. AT THE
SURFACE A COLD FRONT HAS PUSHED SOUTH OVER OUR CWA AND IS
CURRENTLY EXTENDING FRONT NORTON TO CHEYENNE WELLS BEFORE TURNING
BACK TO THE NORTH ALONG THE THE FRONT RANGE IN COLORADO.

THUNDERSTORMS DEVELOPED OVERNIGHT AHEAD OF THIS FRONT IN THE FAR
EASTERN PART OF THE CWA...WITH SUPPORT FROM H85 50KT JET AND
STRONG THETA-E CONVERGENCE IN THE H85-H7 LAYER. SHORT RANGE
GUIDANCE SUPPORTS THIS ACTIVITY PULLING OFF THE EAST THROUGH
SUNRISE...HOWEVER LITTLE WILL CHANGE REGARDING INSTABILITY/FORCING
SO WILL NEED TO MONITOR/REEVALUATE IF I NEED TO KEEP POPS MENTION
BEYOND 15Z FOR THESE LOCATIONS. ADDITIONAL THUNDERSTORM IS
EXPECTED TO DEVELOP THIS AFTERNOON GENERALLY ALONG THE THE STALLED
FRONT...WITH ADDITIONAL FORCING IN THE LATE AFTERNOON THROUGH
EVENING ASSOCIATED WITH SHORTWAVE TROUGH PASSAGE IN NEBRASKA. WITH
FRONT OVER OUR CWA WE SHOULD SEE BETTER COVERAGE ALONG
FRONT. BETTER INSTABILITY GENERALLY TO THE NORTH OF THE FRONT
WHERE TD VALUES IN THE 60S WILL BE...SO I KEPT CHANCE POPS
GENERALLY OVER THE NW CWA. NAM/RAP BOTH SHOW SB/ML CAPE IN EXCESS
OF 2000 J/KG NORTH OF THIS FRONT WHICH COULD CERTAINLY SUPPORT
STRONG UPDRAFTS. SHEER ON THE OTHER HAND IS NOT QUITE AS
STRONG (0-6KM 20-25KT). THERE DOES APPEAR TO BE ENOUGH SUPPORT FOR
AN ELEVATED LARGE HAIL/STRONG WIND THREAT WITH THUNDERSTORMS THAT
DEVELOP.

AFTER TOMORROW NIGHT PRECIP CHANCES DECREASE SIGNIFICANTLY WITH
INCREASING CAP AND STRONGER SUBSIDENCE ASSOCIATED WITH BUILDING
RIDGE. THERE IS SOME INDICATION OF THUNDERSTORMS MOVING INTO THE
FAR NW PART OF THE CWA FRIDAY AFTERNOON/EVENING...SO I ADDED
SLIGHT CHANCE POPS. BY SATURDAY THE MEAN STORM TRACK WILL HAVE
SHIFTED FAR ENOUGH NORTH WITH STRONG CINH AND LARGE SCALE
SUBSIDENCE INHIBITING AFTERNOON/EVENING CHANCES.

TEMPS WILL DROP CLOSER TO SEASONAL NORMS TODAY BEHIND FRONT IN
THE UPPER 80S/LOW 90S. TH TREND WILL BE MUCH ABOVE NORMAL FRIDAY
AND SATURDAY WITH STRONG RIDGE (595DM) AND STRONG WAA ASSOCIATED
WITH SOUTHERLY FLOW EAST OF STRENGTHENING LEE TROUGH. HAVE TRENDED
TEMPS TOWARDS UPPER 90S BASED ON MIXING WED...AND MIGHT BE A FEW
DEGREES TOO COOL WITH TEMPS NEAR 100F NOT OUT OF THE QUESTION.

.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 248 AM MDT THU AUG 22 2013

FORECAST PATTERN FOR THE WEEKEND AND EARLY NEXT WEEK HAS CHANGED
LITTLE OVER THE PAST FEW DAYS. A STRONG UPPER-LEVEL RIDGE WILL BE
CENTERED OVER THE CENTRAL PLAINS FOR MUCH OF THE PERIOD...WITH THE
GEM AND ECMWF PLACING THE UPPER HIGH JUST EAST OF THE CENTRAL
PLAINS. WHILE THE RIDGE IS IN PLACE PRECIP CHANCES WILL BE NEAR-NIL
AS DISTURBANCES ROTATE AROUND THE RIDGE. TEMPS WILL BE WELL ABOVE
NORMAL WITH 850MB TEMPS IN THE LOW 30S C...TRANSLATING TO HIGHS IN
THE MID TO UPPER 90S. WOULD NOT BE SURPRISED TO SEE SOME SPOTS HIT
THE TRIPLE DIGITS MON OR TUES...THE HEAT PEAKING AROUND TUESDAY
BEFORE THE RIDGE SHIFTS A BIT FURTHER EAST INTO THE MIDDLE OF THE
WEEK. WINDS DURING THE PERIOD WILL BE PRETTY BREEZY OUT OF THE
SOUTH AT 15 TO 20 MPH DURING THE AFTERNOONS AS A NORTH-SOUTH
ORIENTED SURFACE TROUGH DEVELOPS IN EASTERN COLORADO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1130 PM MDT WED AUG 21 2013

VFR CONDITIONS ARE FORECAST FOR THE 6Z TAFS. CURRENT RADAR SHOWS
THE COLD FRONT MOVING SOUTH THROUGH THE AREA. IF THE FRONT
CONTINUES SOUTH AT ITS PRESENT SPEED...FRONT SHOULD BE THROUGH
BOTH SITES AROUND 7Z. NORTHEAST WINDS MAY GUST TO 20KTS BRIEFLY
BEHIND THE FRONT. AM ANTICIPATING THE FRONT TO CONTINUE TO MOVE
SOUTH THROUGH THE NIGHT INSTEAD OF SLOWING DOWN AS SOME MODELS
SHOW...ALLOWING THE WINDS TO REMAIN FROM THE NORTHEAST THROUGH
MOST OF THE TAF PERIOD. THERE IS A POSSIBILITY OF THUNDERSTORMS
DEVELOPING OVER EAST CENTRAL COLORADO INTO WESTERN KS THURSDAY
AFTERNOON...BUT DO NOT BELIEVE THE COVERAGE WILL BE ENOUGH TO
WARRANT A MENTION IN THE TAF AT THIS TIME.


&&

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

$$

SHORT TERM...DR
LONG TERM...JJM
AVIATION...JTL







AREA FORECAST DISCUSSION

NWS JACKSON KY

 338 PM EDT THU AUG 22 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 337 PM EDT THU AUG 22 2013

ISOLATED TO SCATTERED CONVECTION ACROSS THE AREA HAS REMAINED
UNORGANIZED AND TAME SO FAR TODAY...WITH LITTLE UPPER LEVEL SUPPORT
AVAILABLE. A SHORT WAVE ON WATER VAPOR IMAGERY OVER THE UPPER MS
VALLEY IS MOVING ESE...WHILE AN OLD OUTFLOW BOUNDARY AT THE SURFACE
IS FOCUSING CONVECTIVE DEVELOPMENT ACROSS CENTRAL OH AND INDIANA.

AS THE SHORT WAVE MOVES INTO THE OH VALLEY TONIGHT...THERE WILL BE
BETTER UPPER LEVEL SUPPORT FOR PRECIPITATION ACROSS THE FORECAST
AREA. THE EXACT EVOLUTION OF CONVECTION DEVELOPING ACROSS OH AND
INDIANA IS UNCERTAIN...AND THE 17Z HRRR HAS MOST PRECIPITATION DYING
OUT BY 02Z. HOWEVER IT DOES SHOW REDEVELOPMENT AROUND 05Z MOST
LIKELY IN ASSOCIATION WITH AN UPPER LEVEL SPEED MAX ASSOCIATED WITH
THE UPPER TROF. THE NAM IS MOST SUPPORTIVE OF PRECIPITATION
OVERNIGHT...BUT THE GFS...ECMWF AND GEM ALL POINT TOWARDS A CHANCE
OF SHOWERS AND THUNDERSTORMS. IT DOES APPEAR THE BEST SUPPORT WILL BE
OVER THE NORTHERN AND EASTERN PORTION OF THE FORECAST AREA AND HAVE
ELECTED TO GO WITH LIKELY PROBABILITY OF RAIN CHANCES IN THESE AREAS
WITH A CHANCE IN THE SOUTHWEST. WEAK COLD FRONT WILL NOT CLEAR THE
AREA UNTIL FRIDAY EVENING...SO WILL CONTINUE WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS FRIDAY...BUT DECREASE CHANCES FROM THE NORTH DURING
THE DAY.

WITH PRECIPITABLE WATER AROUND 1.9 INCHES OR NEAR THE 90TH
PERCENTILE...WILL CONTINUE TO MENTION HEAVY RAIN AND FLASH FLOOD
POSSIBILITY IN THE HAZARDOUS WEATHER OUTLOOK FOR TONIGHT.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 337 PM EDT THU AUG 22 2013

OT A LOT OF CHANGE FROM PREVIOUS FORECAST. MODELS ARE STILL IN
RELATIVELY GOOD AGREEMENT THAT THE UPPER AIR PATTERN WILL CONSIST OF
A LARGE 500MB RIDGE ACROSS THE SOUTH CENTRAL CONUS...EXPECTED TO
REMAIN IN PLACE THROUGH THE DURATION OF THE FORECAST PERIOD. WITH
UPPER LEVEL TROUGHING OFF BOTH THE NW AND NE COAST...EASTERN KY WILL
FIND ITSELF WITHIN THE RIDGING PATTERN...BUT ON THE WINDWARD SIDE OF
THE NE TROUGHING PATTERN. ANY SHORTWAVE THAT TRAVELS ALONG THE
TROUGH AXIS WILL MAKE ITS WAY NEAR EASTERN KY DESPITE THE STRONG
RIDGING IN PLACE. HOWEVER...WITH SOMEWHAT LESS AGREEMENT ON THE
SMALLER SCALE...ANY SHORTWAVES AND RESULTING RAIN CHANCES WILL BE
BEST LEFT TO A MODEL CONSENSUS.

WITH A GOOD VEERING WIND PROFILE...AND TEMPERATURES EXPECTED TO BE
WARMER AND MORE HUMID THAN HAVE BEEN OVER THE PAST FEW WEEKS...ALL
MODELS ARE POINTING AT THE POTENTIAL FOR AFTERNOON INSTABILITY AND
CONVECTION ACROSS THE EASTERN PORTION OF THE STATE THROUGH THE
ENTIRE FORECAST PERIOD. THE ONLY CAVEAT TO THIS IS THE FACT THAT
GFS40 SOUNDINGS /BOTH CURRENT AND PREVIOUS/ ARE SHOWING AN ABUNDANT
AMOUNT OF DRY AIR AT ALL LEVELS...WITH ONLY THE POTENTIAL FOR A SCT
THIN LAYER OF DIURNAL CLOUDS. AND THOUGH THERE IS A GOOD VEERING
PATTERN MENTIONED ABOVE...MOST OF THIS TAKES PLACE IN THE MID LEVELS
RATHER THAN THE LOWER LEVELS...WITH A LOW AMOUNT OF CAPE AND A VERY
LIMITED AMOUNT OF TIME IN THE AFTERNOON WHERE THERE IS NOT A CAPPING
INVERSION. ALL THINGS CONSIDERED...DID PUT IN SOME SLIGHT CHANCE
POPS IN THE AFTERNOON TO GO ALONG WITH MODEL CONSENSUS...BUT EXPECT
THUNDERSTORM DEVELOPMENT TO BE EVEN MORE ISOLATED IN COMPARISON TO
SHOWER POTENTIAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 140 PM EDT THU AUG 22 2013

ISOLATED TO SCATTERED THUNDERSTORMS WILL OCCUR ACROSS THE FORECAST
AREA THIS AFTERNOON...WITH THE MOST WIDESPREAD RAINFALL COVERAGE
EXPECTED TONIGHT AS A COLD FRONT SAGS SOUTH ACROSS OH AND INDIANA
AND INTO KY. OUTSIDE OF SHOWERS AND THUNDERSTORMS VFR CONDITIONS WILL
PREVAIL THIS AFTERNOON...BUT THROUGH MID AFTERNOON THERE WILL BE
SOME AREAS OF MVFR CEILINGS. AFTER MORE WIDESPREAD RAINFALL TONIGHT...
CEILINGS AND VISIBILITIES ARE EXPECTED TO LOWER TO IFR. CEILINGS AND
VISIBILITIES WILL GRADUALLY IMPROVE THROUGH THE MORNING ON FRIDAY.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...SBH
LONG TERM...JMW
AVIATION...SBH







AREA FORECAST DISCUSSION...UPDATED

NWS GRAY ME

 551 PM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT AND WILL BE FOLLOWED BY
HIGH PRESSURE BUILDING IN FROM THE WEST ON FRIDAY. HIGH PRESSURE
WILL CREST OVER THE REGION ON SATURDAY AND WILL SETTLE SOUTH OF THE
REGION ON SUNDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON
MONDAY AND WILL CROSS THE REGION LATE MONDAY NIGHT AND EARLY
TUESDAY. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT TUESDAY AFTERNOON. LOW PRESSURE WILL PASS SOUTHWEST OF THE
FORECAST AREA WEDNESDAY. A WEAK COLD FRONT WILL DROP SOUTH INTO THE
REGION WEDNESDAY NIGHT AND WILL STALL OVER THE AREA ON THURSDAY.

&&

.NEAR TERM /THROUGH FRIDAY/...
UPDATE...HAVE USED THE 19Z HRRR RUN TO TREND POP FOR THE NEXT
SEVERAL HOURS. IT HAS A GOOD HANDLE ON CURRENT CONVECTION...AS
WELL AS EVOLUTION. IT SHOWS A GENERAL WEAKENING TREND OVER THE
NEXT COUPLE OF HOURS...AND BASED ON LIGHTNING OBS AND CLOUD TOP
WARMING THIS APPEARS TO BE THE CASE. THE ALREADY LOW PROB OF
SEVERE WX WILL CONTINUE TO DECLINE AS WE/VE PASSED THE PEAK IN
DIURNAL HEATING.

PREVIOUS DISCUSSION...STRONG SHORT WAVE TROUGH CONTINUES TO PUSH
ACROSS THE NORTHERN GREAT LAKES. ATTENDANT SFC COLD FRONT
CONTINUES TO MOVE EASTWARD IN ADVANCE OF THE SHORT WAVE TROUGH
ACROSS EASTERNMOST ONTARIO AND SOUTHERN QUEBEC. SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED IN ADVANCE OF THE COLD FRONT IN
NORTHERNMOST NY AND NORTHWESTERN VT. A FEW STORMS HAVE ALSO
DEVELOPED NEAR THE SOMERSET/PISCATAQUIS COUNTY BORDER IN MAINE AND
ARE MOVING EAST.

AS THE COLD FRONT CONTINUES TO MARCH EASTWARD OVER THE NEXT
SEVERAL HOURS...THE SHOWERS AND STORMS OVER NORTHERN NY AND VT
WILL MOVE EASTWARD INTO NORTHERN NH AND THE WESTERN ME MOUNTAINS.
WHILE DEEP LAYER SHEAR IS QUITE WEAK...ENOUGH INSTABILITY EXISTS
IN TANDEM WITH 20-30 DEGREE SFC DEWPOINT DEPRESSIONS TO ALLOW FOR
A LOW PROB OF ISOLATED STRONG TO DAMAGING WIND GUSTS WITH THIS
ACTIVITY LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. HIGHEST
POPS HAVE BEEN PLACED IN THIS AREA...MAINLY NORTH OF A LEBANON NH-
SKOWHEGAN ME LINE.

FURTHER SOUTH...ACTIVITY LOOKS TO REMAIN A LOT MORE ISOLATED. THE
ONLY CAVEAT IS IF A LINE OF SHOWERS AND STORMS DEVELOPS ON THE
NOSE OF THE SHORT WAVE TROUGH AND SFC COLD FRONT AND MOVES ACROSS
THE AREA LATE THIS EVENING TO JUST AFTER MIDNIGHT. THE LATEST FEW
RUNS OF THE HRRR HAS SUGGESTED THIS. GIVEN THE STRENGTH OF THE
FORCING...HAVE INCREASED POPS TO ACCOUNT FOR THIS POSSIBILITY
AFTER DARK. JUST WINDS AND HEAVY DOWNPOURS WILL REMAIN POSSIBLE
WITH THIS ACTIVITY. ANY PRECIPITATION SHOULD SWEEP OFFSHORE BEFORE
DAWN.

&&

.SHORT TERM /FRIDAY NIGHT/...
DEEP UPPER TROUGH MOVES ACROSS THE AREA ON FRIDAY. SO EVEN THOUGH
SFC HIGH PRESSURE MOVES INTO THE AREA...THERE SHOULD BE PLENTY OF
STRATOCU AROUND...AS WELL AS THE SLIGHT CHANCE OF SHOWERS AND
PERHAPS A SPRINKLE.

HIGH PRESSURE CONTINUES TO MOVE IN FRIDAY NIGHT. SKIES SHOULD
CLEAR IN THE EVENING AND WINDS SHOULD GO CALM. THIS WILL LEAD TO
STRONG RADIATIONAL COOLING...WITH A FEW AREAS IN NORTHERN NH
POSSIBLY DROPPING INTO THE MID 30S. SCATTERED FROST?

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BUILD OVER NEW ENGLAND SATURDAY AND WILL
GRADUALLY SETTLE SOUTH OF THE REGION ON SUNDAY. BOTH DAYS LOOKING
VERY NICE WITH ABUNDANT SUNSHINE AND LIGHT WINDS. SHOULD SEE HIGHS
SATURDAY RANGING THROUGH THE 70S FROM NORTH TO SOUTH. WILL TACK ON A
DEGREE OR TWO ON SUNDAY. SATURDAY NIGHT LOOKING PRETTY CHILLY WITH
SOME MOUNTAIN VALLEYS DIPPING INTO THE UPPER 30S. SOUTHERN AREAS
WILL RANGE FROM THE MID 40S TO LOWER 50S ALONG THE COAST.

A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON MONDAY BUT MOST OF
THE DAY WILL BE SUNNY WITH INCREASING HUMIDITY. TEMPERATURES WILL
ALSO BE ON THE INCREASE WITH MOST AREAS AWAY FROM THE COAST GETTING
INTO THE LOWER TO MID 80S. WILL SEE INCREASING CLOUDS IN NORTHWEST
ZONES DURING THE LATTER HALF OF THE AFTERNOON WITH A CHANCE OF A
SHOWER OR THUNDERSTORM BY EVENING.

COLD FRONT WILL SWING THROUGH MONDAY NIGHT AND EARLY TUESDAY
BRINGING A ROUND SHOWERS AND THUNDERSTORMS TO THE AREA. AFTER A
CLOUDY START TO THE DAY WILL SEE GRADUAL CLEARING FROM EAST TO WEST
IN THE AFTERNOON. NOT A BIG PUSH OF COLD AIR BEHIND THE FRONT SO
WILL SEE HIGHS FROM THE MID 70S TO LOWER 80S.

WEAK RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST TUESDAY NIGHT AS
LOW PRESSURE APPROACHES FROM THE WEST. LOW PRESSURE FORECAST TO PASS
SOUTHWEST OF THE REGION ON WEDNESDAY. WILL SEE VARIABLE CLOUDINESS
DURING THE DAY BUT AT THIS POINT LOOKS LIKE ANY PRECIP REMAINS SOUTH
OF THE FORECAST AREA ACROSS SOUTHERN NEW ENGLAND.

LOW PRESSURE HEADS OUT TO SEA WEDNESDAY NIGHT AS A WEAK COLD FRONT
DROPS SOUTH INTO NORTHERN ZONES. WILL SEE A CHANCE OF A SHOWER OR
THUNDERSTORM BOTH WEDNESDAY NIGHT AND THURSDAY AS THIS BOUNDARY
STALLS OVER THE REGION.

&&

.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...LOCAL MVFR OR LOWER CONDITIONS IN SHOWERS AND
THUNDERSTORMS POSSIBLY THROUGH MIDNIGHT TONIGHT...THEN VFR
CONDITIONS EXPECTED LATE TONIGHT THROUGH FRIDAY NIGHT. VALLEY FOG
LIKELY LATE FRIDAY NIGHT.

LONG TERM...VFR SATURDAY THROUGH MONDAY. AREAS MVFR/IFR CEILINGS
MONDAY NIGHT. VFR TUESDAY.

&&

.MARINE...
SHORT TERM...MARGINAL SCA POSSIBLE TONIGHT INTO FRIDAY WITH A FEW
5 FOOTERS POSSIBLE ON THE OCEAN. HOWEVER...HAVE HELD OFF ON ANY
SCA FOR NOW SINCE MODELS TEND TO BE OVERDOING THE SEAS A BIT AT
THE MOMENT.

LONG TERM...SCA`S LIKELY NEEDED ON MONDAY AND MONDAY NIGHT.

&&

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

&&

$$

NEAR TERM...LEGRO








AREA FORECAST DISCUSSION

NWS GRAY ME

 244 PM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT AND WILL BE FOLLOWED BY
HIGH PRESSURE BUILDING IN FROM THE WEST ON FRIDAY. HIGH PRESSURE
WILL CREST OVER THE REGION ON SATURDAY AND WILL SETTLE SOUTH OF THE
REGION ON SUNDAY. A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON
MONDAY AND WILL CROSS THE REGION LATE MONDAY NIGHT AND EARLY
TUESDAY. A WEAK RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE
FRONT TUESDAY AFTERNOON. LOW PRESSURE WILL PASS SOUTHWEST OF THE
FORECAST AREA WEDNESDAY. A WEAK COLD FRONT WILL DROP SOUTH INTO THE
REGION WEDNESDAY NIGHT AND WILL STALL OVER THE AREA ON THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
STRONG SHORT WAVE TROUGH CONTINUES TO PUSH ACROSS THE NORTHERN
GREAT LAKES. ATTENDANT SFC COLD FRONT CONTINUES TO MOVE EASTWARD
IN ADVANCE OF THE SHORT WAVE TROUGH ACROSS EASTERNMOST ONTARIO AND
SOUTHERN QUEBEC. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED IN
ADVANCE OF THE COLD FRONT IN NORTHERNMOST NY AND NORTHWESTERN VT.
A FEW STORMS HAVE ALSO DEVELOPED NEAR THE SOMERSET/PISCATAQUIS
COUNTY BORDER IN MAINE AND ARE MOVING EAST.

AS THE COLD FRONT CONTINUES TO MARCH EASTWARD OVER THE NEXT
SEVERAL HOURS...THE SHOWERS AND STORMS OVER NORTHERN NY AND VT
WILL MOVE EASTWARD INTO NORTHERN NH AND THE WESTERN ME MOUNTAINS.
WHILE DEEP LAYER SHEAR IS QUITE WEAK...ENOUGH INSTABILITY EXISTS
IN TANDEM WITH 20-30 DEGREE SFC DEWPOINT DEPRESSIONS TO ALLOW FOR
A LOW PROB OF ISOLATED STRONG TO DAMAGING WIND GUSTS WITH THIS
ACTIVITY LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. HIGHEST
POPS HAVE BEEN PLACED IN THIS AREA...MAINLY NORTH OF A LEBANON NH-
SKOWHEGAN ME LINE.

FURTHER SOUTH...ACTIVITY LOOKS TO REMAIN A LOT MORE ISOLATED. THE
ONLY CAVEAT IS IF A LINE OF SHOWERS AND STORMS DEVELOPS ON THE
NOSE OF THE SHORT WAVE TROUGH AND SFC COLD FRONT AND MOVES ACROSS
THE AREA LATE THIS EVENING TO JUST AFTER MIDNIGHT. THE LATEST FEW
RUNS OF THE HRRR HAS SUGGESTED THIS. GIVEN THE STRENGTH OF THE
FORCING...HAVE INCREASED POPS TO ACCOUNT FOR THIS POSSIBILITY
AFTER DARK. JUST WINDS AND HEAVY DOWNPOURS WILL REMAIN POSSIBLE
WITH THIS ACTIVITY. ANY PRECIPITATION SHOULD SWEEP OFFSHORE BEFORE
DAWN.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
DEEP UPPER TROUGH MOVES ACROSS THE AREA ON FRIDAY. SO EVEN THOUGH
SFC HIGH PRESSURE MOVES INTO THE AREA...THERE SHOULD BE PLENTY OF
STRATOCU AROUND...AS WELL AS THE SLIGHT CHANCE OF SHOWERS AND
PERHAPS A SPRINKLE.

HIGH PRESSURE CONTINUES TO MOVE IN FRIDAY NIGHT. SKIES SHOULD
CLEAR IN THE EVENING AND WINDS SHOULD GO CALM. THIS WILL LEAD TO
STRONG RADIATIONAL COOLING...WITH A FEW AREAS IN NORTHERN NH
POSSIBLY DROPPING INTO THE MID 30S. SCATTERED FROST?

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BUILD OVER NEW ENGLAND SATURDAY AND WILL
GRADUALLY SETTLE SOUTH OF THE REGION ON SUNDAY. BOTH DAYS LOOKING
VERY NICE WITH ABUNDANT SUNSHINE AND LIGHT WINDS. SHOULD SEE HIGHS
SATURDAY RANGING THROUGH THE 70S FROM NORTH TO SOUTH. WILL TACK ON A
DEGREE OR TWO ON SUNDAY. SATURDAY NIGHT LOOKING PRETTY CHILLY WITH
SOME MOUNTAIN VALLEYS DIPPING INTO THE UPPER 30S. SOUTHERN AREAS
WILL RANGE FROM THE MID 40S TO LOWER 50S ALONG THE COAST.

A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON MONDAY BUT MOST OF
THE DAY WILL BE SUNNY WITH INCREASING HUMIDITY. TEMPERATURES WILL
ALSO BE ON THE INCREASE WITH MOST AREAS AWAY FROM THE COAST GETTING
INTO THE LOWER TO MID 80S. WILL SEE INCREASING CLOUDS IN NORTHWEST
ZONES DURING THE LATTER HALF OF THE AFTERNOON WITH A CHANCE OF A
SHOWER OR THUNDERSTORM BY EVENING.

COLD FRONT WILL SWING THROUGH MONDAY NIGHT AND EARLY TUESDAY
BRINGING A ROUND SHOWERS AND THUNDERSTORMS TO THE AREA. AFTER A
CLOUDY START TO THE DAY WILL SEE GRADUAL CLEARING FROM EAST TO WEST
IN THE AFTERNOON. NOT A BIG PUSH OF COLD AIR BEHIND THE FRONT SO
WILL SEE HIGHS FROM THE MID 70S TO LOWER 80S.

WEAK RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST TUESDAY NIGHT AS
LOW PRESSURE APPROACHES FROM THE WEST. LOW PRESSURE FORECAST TO PASS
SOUTHWEST OF THE REGION ON WEDNESDAY. WILL SEE VARIABLE CLOUDINESS
DURING THE DAY BUT AT THIS POINT LOOKS LIKE ANY PRECIP REMAINS SOUTH
OF THE FORECAST AREA ACROSS SOUTHERN NEW ENGLAND.

LOW PRESSURE HEADS OUT TO SEA WEDNESDAY NIGHT AS A WEAK COLD FRONT
DROPS SOUTH INTO NORTHERN ZONES. WILL SEE A CHANCE OF A SHOWER OR
THUNDERSTORM BOTH WEDNESDAY NIGHT AND THURSDAY AS THIS BOUNDARY
STALLS OVER THE REGION.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SHORT TERM...LOCAL MVFR OR LOWER CONDITIONS IN SHOWERS AND
THUNDERSTORMS POSSIBLY THROUGH MIDNIGHT TONIGHT...THEN VFR
CONDITIONS EXPECTED LATE TONIGHT THROUGH FRIDAY NIGHT. VALLEY FOG
LIKELY LATE FRIDAY NIGHT.

LONG TERM...VFR SATURDAY THROUGH MONDAY. AREAS MVFR/IFR CEILINGS
MONDAY NIGHT. VFR TUESDAY.

&&

.MARINE...
SHORT TERM...MARGINAL SCA POSSIBLE TONIGHT INTO FRIDAY WITH A FEW
5 FOOTERS POSSIBLE ON THE OCEAN. HOWEVER...HAVE HELD OFF ON ANY
SCA FOR NOW SINCE MODELS TEND TO BE OVERDOING THE SEAS A BIT AT
THE MOMENT.

LONG TERM...SCA`S LIKELY NEEDED ON MONDAY AND MONDAY NIGHT.

&&

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

&&

$$

NEAR/SHORT TERM...EKSTER







AREA FORECAST DISCUSSION

NWS PITTSBURGH PA

 203 PM EDT THU AUG 22 2013

.SYNOPSIS...
SHOWERS WILL BE LIKELY AS A COLD FRONT CROSSES THE AREA THROUGH
FRIDAY MORNING.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE REALLY TAKEN THEIR TIME GETTING THEIR ACT TOGETHER.
SHOWERS HAVE FINALLY REDEVELOPED TO THE NORTH AND EAST OF
PITTSBURGH...WHILE LINE HAS GENERALLY HELD TOGETHER FROM THE
WESTERN LAKE ERIE SHORELINE AS IT MOVED INTO EASTERN OHIO AND THE
NORTHERN WEST VIRGINIA PANHANDLE. HAVE CHANGED POPS FOR TIMING OF
PRECIPITATION BASED ON RADAR TRENDS. THAT BEING SAID...AREAS SUCH
AS MERCER AND VENANGO COUNTY MAY REMAIN COMPLETELY DRY. THE LAST
FEW RUNS OF THE HRRR ATTEMPT TO HAVE ANOTHER LINE OF SHOWERS
DEVELOP ACROSS THE INTERSTATE 80 CORRIDOR WITH THE ACTUAL FRONTAL
PASSAGE LATE THIS AFTERNOON...BUT THE HRRR ALSO INDICATED THAT THE
CURRENT LINE OF SHOWERS WAS GOING TO HANG TOGETHER ALONG THE I-80
CORRIDOR WHICH DID NOT HAPPEN. HAVE STILL KEPT POPS GOING THROUGH
THE AFTERNOON HOURS IN ALL LOCATIONS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SOUTHWARD IMPETUS FOR THE TRANSLATION OF THE FRONT SEEMS LIKE IT
SLOWLY FADES GOING INTO TONIGHT AND ESPECIALLY FRIDAY MORNING AS
THE MID-LEVEL FORCING ASSOCIATED WITH THE SYSTEM WILL HAVE ALREADY
SCREAMED EASTWARD INTO SOUTHERN QUEBEC AND MARITIME CANADA BY
FRIDAY MORNING. THIS LEAVES THE FRONT`S FORWARD PROGRESS TO SLOW
FAIRLY RAPIDLY AS IT STARTS TO LOSE DEFINITION THROUGH FRIDAY
MORNING. WITH THE FRONT HUNG UP...BOTH THE GFS AND NAM LIKE THE
IDEA OF RUNNING A SECONDARY VORT DOWN THE BOUNDARY LATE TONIGHT
INTO FRIDAY MORNING THAT MANAGES TO CLIP THE SOUTHERN AND
ESPECIALLY SOUTHEASTERN PORTIONS OF THE FORECAST AREA. DEEP LAYER
WESTERLY FLOW COMBINED WITH INSTABILITY AS WELL AS THE INTERACTION
WITH THE RIGHT ENTRANCE REGION OF THE UPPER JET THAT WILL BE
SITUATED OVER NORTHERN PENNSYLVANIA BY THAT TIME SHOULD ALLOW FOR
FAIRLY WIDESPREAD SHOWER DEVELOPMENT OVERNIGHT INTO FRIDAY MORNING
ACROSS THE SOUTHEASTERN ZONES. POPS WERE INCREASED SUBSTANTIALLY
IN THIS AREA TO ACCOUNT FOR BOTH LARGE SCALE AS WELL AS OROGRAPHIC
PRECIPITATION ENHANCEMENT.

BY FRIDAY AFTERNOON...EVEN THE LAGGARD MODEL SOLUTIONS PEEL LIFT
OFF TO THE EAST AND FINALLY ALLOW THE FRONT TO SAG SOUTH OF THE
AREA. DRIER AIR QUICKLY MOVES INTO THE REGION...AS SKIES SEEM TO
RAPIDLY CLEAR. MUCH COOLER CONDITIONS/CALMER CONDITIONS WILL
INFILTRATE THE AREA BY FRIDAY NIGHT WITH ABUNDANT SUNSHINE THROUGH
MOST OF THE WEEKEND.

THE ONLY POSSIBLE CAVEAT TO THE FORECAST LIES IN THE FACE THAT THE
MID AND UPPER RIDGE NEVER MANAGES TO MAKE ITS WAY ALL THE WAY
TOWARD OUR REGION. WITH A RIDGE AXIS GENERALLY WEST OF THE
MISSISSIPPI RIVER...AND OFF SHORE TROUGHING BECOMING SEMI-
RESIDENT...THAT LEAVES OUR REGION IN PERSISTENT NORTHWESTERLY
FLOW. THIS WILL KEEP TEMPERATURES LARGELY IN CHECK THROUGH THE
WEEKEND...BUT ALSO LEAVES THE DOOR OPEN TO CONVECTIVE DEVELOPMENT
THAT MAY MANAGE TO SQUEAK OVER THE RIDGE AXIS. PREVIOUS VERSIONS
OF THE DGEX/ECMWF DID TRY TO EDGE A BIT OF THIS ACTIVITY TOWARD
THE AREA INTO LATE SUNDAY. THE CURRENT RUNS DO NOT FAVOR THIS
SOLUTION...SO THE FORECAST WAS KEPT DRY THROUGHOUT THE
WEEKEND...HOWEVER POPS WERE ALLOWED TO BE NON-ZERO BY SUNDAY TO
ACCOUNT FOR THE EXCEEDINGLY SMALL SHOT AT A SHOWER BY LATE IN THE
DAY. HOWEVER...ALL IN ALL...A DRY AND FAIRLY SUNNY WEEKEND LOOKS
TO BE IN STORE ON ALL CURRENT GUIDANCE WITH TEMPERATURES TRENDING
TOWARD NORMAL. FRIES

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE MODELS AGREE THAT AN UPPER LEVEL RIDGE WILL BUILD OVER THE
CENTRAL PLAINS THROUGH THE LONG TERM. DESPITE THE CONSENSUS IN THE
OVERALL UPPER LEVEL PATTERN...THERE REMAINS INHERENT DIFFERENCES IN
SHORTWAVE TIMING AND PLACEMENT AS THE MODELS SUGGEST SEVERAL WAVES
WILL DROP THROUGH THE NORTHWEST FLOW OVER THE GREAT LAKES/OHIO
VALLEY. WITH THIS IN MIND...CONTINUED TO CARRY AT LEAST CHANCE
POPS THROUGH MUCH OF THE FORECAST PERIOD. DESPITE NORTHWEST
FLOW...BOTH TEMPERATURES AND DEWPOINTS SHOULD INCREASE THROUGH
MIDWEEK BRINGING A RETURN TO HOT AND HUMID CONDITIONS. FOR
NOW...MAINTAINED HIGHS JUST AT OR ABOVE SEASONAL AVERAGES.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
VCTS IN THE TAFS AS THIN LINE OF SHOWERS AND SCATTERED
THUNDERSTORMS ASSOCIATED WITH A COLD FRONT CROSS THE REGION. THE
COLD FRONT COMPLETES PASSAGE ACRS THE UPR OH VLY EARLY TONIGHT BUT
DEWPOINTS WILL BE SLOW TO FALL SO EXPECT SOME MVFR RESTRICTIONS
DUE TO FOG/HAZE IN EARLY MORNING HOURS.

.OUTLOOK.../FRIDAY THROUGH MONDAY/...
GENERAL VFR CONDITIONS THROUGH THE WEEKEND.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$







AREA FORECAST DISCUSSION

NWS PITTSBURGH PA

 122 PM EDT THU AUG 22 2013

.SYNOPSIS...
SHOWERS WILL BE LIKELY AS A COLD FRONT CROSSES THE AREA THROUGH
FRIDAY MORNING.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS HAVE REALLY TAKEN THEIR TIME GETTING THEIR ACT TOGETHER.
SHOWERS HAVE FINALLY REDEVELOPED TO THE NORTH AND EAST OF
PITTSBURGH...WHILE LINE HAS GENERALLY HELD TOGETHER FROM THE
WESTERN LAKE ERIE SHORELINE AS IT MOVED INTO EASTERN OHIO AND THE
NORTHERN WEST VIRGINIA PANHANDLE. HAVE CHANGED POPS FOR TIMING OF
PRECIPITATION BASED ON RADAR TRENDS. THAT BEING SAID...AREAS SUCH
AS MERCER AND VENANGO COUNTY MAY REMAIN COMPLETELY DRY. THE LAST
FEW RUNS OF THE HRRR ATTEMPT TO HAVE ANOTHER LINE OF SHOWERS
DEVELOP ACROSS THE INTERSTATE 80 CORRIDOR WITH THE ACTUAL FRONTAL
PASSAGE LATE THIS AFTERNOON...BUT THE HRRR ALSO INDICATED THAT THE
CURRENT LINE OF SHOWERS WAS GOING TO HANG TOGETHER ALONG THE I-80
CORRIDOR WHICH DID NOT HAPPEN. HAVE STILL KEPT POPS GOING THROUGH
THE AFTERNOON HOURS IN ALL LOCATIONS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
SOUTHWARD IMPETUS FOR THE TRANSLATION OF THE FRONT SEEMS LIKE IT
SLOWLY FADES GOING INTO TONIGHT AND ESPECIALLY FRIDAY MORNING AS
THE MID-LEVEL FORCING ASSOCIATED WITH THE SYSTEM WILL HAVE ALREADY
SCREAMED EASTWARD INTO SOUTHERN QUEBEC AND MARITIME CANADA BY
FRIDAY MORNING. THIS LEAVES THE FRONT`S FORWARD PROGRESS TO SLOW
FAIRLY RAPIDLY AS IT STARTS TO LOSE DEFINITION THROUGH FRIDAY
MORNING. WITH THE FRONT HUNG UP...BOTH THE GFS AND NAM LIKE THE
IDEA OF RUNNING A SECONDARY VORT DOWN THE BOUNDARY LATE TONIGHT
INTO FRIDAY MORNING THAT MANAGES TO CLIP THE SOUTHERN AND
ESPECIALLY SOUTHEASTERN PORTIONS OF THE FORECAST AREA. DEEP LAYER
WESTERLY FLOW COMBINED WITH INSTABILITY AS WELL AS THE INTERACTION
WITH THE RIGHT ENTRANCE REGION OF THE UPPER JET THAT WILL BE
SITUATED OVER NORTHERN PENNSYLVANIA BY THAT TIME SHOULD ALLOW FOR
FAIRLY WIDESPREAD SHOWER DEVELOPMENT OVERNIGHT INTO FRIDAY MORNING
ACROSS THE SOUTHEASTERN ZONES. POPS WERE INCREASED SUBSTANTIALLY
IN THIS AREA TO ACCOUNT FOR BOTH LARGE SCALE AS WELL AS OROGRAPHIC
PRECIPITATION ENHANCEMENT.

BY FRIDAY AFTERNOON...EVEN THE LAGGARD MODEL SOLUTIONS PEEL LIFT
OFF TO THE EAST AND FINALLY ALLOW THE FRONT TO SAG SOUTH OF THE
AREA. DRIER AIR QUICKLY MOVES INTO THE REGION...AS SKIES SEEM TO
RAPIDLY CLEAR. MUCH COOLER CONDITIONS/CALMER CONDITIONS WILL
INFILTRATE THE AREA BY FRIDAY NIGHT WITH ABUNDANT SUNSHINE THROUGH
MOST OF THE WEEKEND.

THE ONLY POSSIBLE CAVEAT TO THE FORECAST LIES IN THE FACE THAT THE
MID AND UPPER RIDGE NEVER MANAGES TO MAKE ITS WAY ALL THE WAY
TOWARD OUR REGION. WITH A RIDGE AXIS GENERALLY WEST OF THE
MISSISSIPPI RIVER...AND OFF SHORE TROUGHING BECOMING SEMI-
RESIDENT...THAT LEAVES OUR REGION IN PERSISTENT NORTHWESTERLY
FLOW. THIS WILL KEEP TEMPERATURES LARGELY IN CHECK THROUGH THE
WEEKEND...BUT ALSO LEAVES THE DOOR OPEN TO CONVECTIVE DEVELOPMENT
THAT MAY MANAGE TO SQUEAK OVER THE RIDGE AXIS. PREVIOUS VERSIONS
OF THE DGEX/ECMWF DID TRY TO EDGE A BIT OF THIS ACTIVITY TOWARD
THE AREA INTO LATE SUNDAY. THE CURRENT RUNS DO NOT FAVOR THIS
SOLUTION...SO THE FORECAST WAS KEPT DRY THROUGHOUT THE
WEEKEND...HOWEVER POPS WERE ALLOWED TO BE NON-ZERO BY SUNDAY TO
ACCOUNT FOR THE EXCEEDINGLY SMALL SHOT AT A SHOWER BY LATE IN THE
DAY. HOWEVER...ALL IN ALL...A DRY AND FAIRLY SUNNY WEEKEND LOOKS
TO BE IN STORE ON ALL CURRENT GUIDANCE WITH TEMPERATURES TRENDING
TOWARD NORMAL. FRIES

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE MODELS AGREE THAT AN UPPER LEVEL RIDGE WILL BUILD OVER THE
CENTRAL PLAINS THROUGH THE LONG TERM. DESPITE THE CONSENSUS IN THE
OVERALL UPPER LEVEL PATTERN...THERE REMAINS INHERENT DIFFERENCES IN
SHORTWAVE TIMING AND PLACEMENT AS THE MODELS SUGGEST SEVERAL WAVES
WILL DROP THROUGH THE NORTHWEST FLOW OVER THE GREAT LAKES/OHIO
VALLEY. WITH THIS IN MIND...CONTINUED TO CARRY AT LEAST CHANCE
POPS THROUGH MUCH OF THE FORECAST PERIOD. DESPITE NORTHWEST
FLOW...BOTH TEMPERATURES AND DEWPOINTS SHOULD INCREASE THROUGH
MIDWEEK BRINGING A RETURN TO HOT AND HUMID CONDITIONS. FOR
NOW...MAINTAINED HIGHS JUST AT OR ABOVE SEASONAL AVERAGES.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
WILL CONTINUE TO CARRY VCTS IN THE TAFS FOR THIS AFTERNOON AS
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A COLD FRONT CROSS THE
OHIO VALLEY. TRIED TO TIME THE THUNDER MENTION BASED OFF OF THE
MOST RECENT HI RES MODEL DATA...STARTING AT ZZV AND FKL AND MOVING
SOUTHEASTWARD. WESTERLY WIND FROM 5 TO 10KTS WITH HIGHER GUSTS
POSSIBLE IN THUNDERSTORMS. RESTRICTION POTENTIAL WL CONTINUE INTO
TONIGHT AS THE CDFNT COMPLETES PASSAGE ACRS THE UPR OH VLY.

.OUTLOOK.../FRIDAY THROUGH MONDAY/...
GENL IMPROVEMENT MAY BE ANTICIPATED FRIDAY AS HIGH PRES BLDS
THROUGH THE WEEKEND.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$







AREA FORECAST DISCUSSION

NWS WAKEFIELD VA

 227 AM EDT THU AUG 22 2013

.SYNOPSIS...
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL SLIDE EAST INTO THE REGION
TONIGHT AND THURSDAY BEFORE EXITING THURSDAY NIGHT. A STRONG COLD
FRONT WILL SLIDE THROUGH THE REGION ON FRIDAY. HIGH PRESSURE WILL
BUILD IN FROM THE NORTH FRIDAY NIGHT THROUGH THE COMING WEEKEND
WITH DRIER AND COOLER WEATHER.

&&

.NEAR TERM /THROUGH TODAY/...
FORECAST UPDATED FOR POPS AND ADDING PATCHY FOG. GENERAL IDEA WAS
TO DECREASE POPS FOR THE OVRNGT HRS (BASED ON RADAR TRENDS AND
LATEST MODEL GUIDANCE).

PREVIOUS DISCUSSION...
WATER VAPOR IMAGERY SHOWS A STRONG UPPER LOW OVER THE OHIO VALLEY
WITH JET ENERGY NOW BEGINNING TO MOVE UNDER AND UP THE EASTERN
SIDE OF THE TROUGH. THE 12Z NAM SHOWS THAT THE JET AT 300 MB IS
AROUND 6O KTS. THIS JET WILL HELP TO PULL THE TROUGH EASTWARD THIS
EVENING WHILE ALSO HELPING TO AID IN THE CONVECTION THAT HAS BEEN
FIRING OVER THE HIGHER TERRAIN WEST OF THE AREA. AS THIS FEATURE
PULLS EAST...EXPECT THAT THE CONVECTION OVER THE NC PIEDMONT AND
BEGINNING TO DEVELOP OVER THE VA PIEDMONT WILL PULL EAST INTO
EASTERN VIRGINIA AND EVENTUALLY LIFT NE INTO THE LOWER MD EASTERN
SHORE. HAVE BEEN A LITTLE AGGRESSIVE WITH POPS THIS AFTERNOON
SHOWING AN AREA OF LIKELY POPS NEAR PTB/RIC. THESE POPS MAY BE A
TOUCH HIGH...BUT WITH RADAR SHOWING LOTS OF CONVECTION NOT FAR
AWAY AND THE UPPER LOW BEGINNING TO MOVE WILL KEEP THE 60 POPS IN
FOR NOW. AFTER 6Z...THE JET ENERGY AND SHORTWAVE ENERGY WILL BE
NORTH AND EAST OF THE AREA...AND SHOULD BEGIN TO FEEL THE
INFLUENCE OF THE DRY AIR...SHOWING UP ON THE WATER VAPOR NOW OVER
TN. THIS SHOULD HELP TO SHUT DOWN THE CONVECTION SO HAVE TAPERED
POPS OVERNIGHT. FOR LOWS OVERNIGHT...WITH THE SFC NOT CHANGING AIR
MASS AND LOT OF CLOUDS WITH GOOD MOISTURE HAVE LEANED TOWARD THE
WARMER NUMBERS...TRYING TO GET NEAR OR JUST ABOVE LAST NIGHT LOWS.

ON THURSDAY...THE UPPER TROUGH WILL BE OVER THE AREA AND SLIDING
EAST. THE 12Z NAM AND GFS BOTH SHOW MORE SHORTWAVE ENERGY DIVING
DOWN THE BACK SIDE OF THE TROUGH WITH A VERY MOIST LOW LEVEL AIR
MASS STILL IN PLACE...SCATTERED CONVECTION IS STILL POSSIBLE SO
HAVE HELD ON TO SOME AFTERNOON POPS AS THE TROUGH EXITS. FOR
HIGHS...THE GFS HAS BEEN MUCH BETTER TODAY AND THE NAM SEEMS TO
COOL THE ATMOSPHERE A LITTLE TO MUCH SO HAVE LEANED TOWARD THE
GFS/MAV NUMBERS GETTING HIGHS INTO THE U80S-NR 90 DEGREES.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE UPPER TROUGH EXITS QUICKLY THURS EVENING...AND THEN A STRONG
COLD FRONT...NOW OVER THE UPPER MIDWEST WILL MOVE THROUGH THE
GREAT LAKES AN INTO THE MID ATLANTIC STATES LATE THURS NIGHT AND
FRIDAY. THE LIFT FIELDS IN THE MODELS ARE NOT ALL THAT IMPRESSIVE
AND THE SFC CONVERGENCE LOOKS A BIT WEAK. BUT WITH THE AMOUNT OF
MOISTURE AROUND...HAVE HELD ON TO SOME LOW CHANCE POPS ALONG THE
FRONT. THE MODELS HAVE SLOWED A TOUCH WITH THE SPEED FOCUSING MORE
OF THE FRONT ON FRIDAY...BUT THEY DO CONTINUE TO PUSH THE FRONT
WELL SOUTH OF THE AREA BY SATURDAY. NORMALLY THE MODELS ARE A BIT
BULLISH THIS TIME OF YR WITH THE FRONTS...BUT THERE IS A VERY
STRONG AREA OF HIGH PRESSURE...ABOUT 1026 MB IN THE NAM...WHICH
SUPPORTS GETTING THE FRONT COMPLETELY SOUTH OF THE AREA. THIS WILL
BRING AN END TO THE SHOWER CHANCES ON FRI NIGHT AND ALLOW FOR A
MUCH COOLER AND DRIER AIR MASS FOR SATURDAY.

FOR TEMPERATURES HAVE LEANED TOWARD THE MAV NUMBERS A LITTLE MORE
ON FRIDAY BASED UPON CURRENT TRENDS AND THE FACT THAT THE AIR MASS
REALLY DOES NOT CHANGE UNTIL THE COLD FRONT PASSES ON FRI EVENING.
BY SATURDAY...WITH DRIER AIR AND COOLER AIR ALOFT SHOULD SEE
COOLER HIGHS IN THE LOW TO MID 80S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
VERY LITTLE CHANGE TO EXTENDED PORTION OF THE FORECAST. A
LARGE-SCALE AREA OF HIGH PRESSURE SETTLES INTO THE MID ATLANTIC
STATES THROUGH THE WEEKEND AND ORIGINATES FROM THE HUDSON BAY AREA
OF CANADA. THIS WILL BRING A MUCH COOLER AND DRIER AIR MASS TO THE
REGION DURING THIS TIME. EXPECT A GRADUAL COOLING TREND THROUGH
SUNDAY NIGHT WITH HIGHS IN THE LOWER 80S (MID TO UPPER 70S IMMEDIATE
COAST) AND LOWS IN THE LOW TO MID 60S (POSSIBLY UPPER 50S IN THE
EASTERN PIEDMONT). CONDITIONS BEGIN TO REBOUND SLIGHTLY ON MONDAY AS
HIGH PRESSURE SHIFTS SOUTHEAST OFF THE CAROLINA COAST. ON
TUESDAY...A LEE TROUGH DEVELOPS AND A BACKDOOR FRONT PASSES OVER NE
COUNTIES (ESPECIALLY THE MD/VA EASTERN SHORE). THE BACKDOOR FRONT
SHOULD ACT AS A CATALYST FOR LONGWAVE TROUGHING TO COMMENCE OVER THE
NE CONUS DURING THE SECOND HALF OF NEXT WEEK. IF THIS TREND
CONTINUES...THEN ANTICIPATE A RETURN TO WARMER TEMPS BUT SHOWERY
CONDITIONS WITH EACH PASSING DAY.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
SCTD SHWRS AND TSTMS CONTINUE OVER EASTERN PORTIONS OF THE AREA IN
ASSOCIATION WITH A WEAK UPR TROF MOVING ACROSS THE AREA. HAVE
ATTEMPTED TO USE CURRENT RADAR TO TIME/PLACE ANY PRECIP IN TAFS.
TROF MOVES ACROSS REGION THROUGH 12Z...WITH CHANCES FOR SHWRS AND
ISOLATED TSTMS PERSISTING. THERE MAY BE SOME ADDITIONAL SHWR/TSTM
ACTIVITY THURSDAY AFTERNOON...BUT HAVE LEFT OUT OF 06Z TAFS
PRIMARILY DUE TO TIMING UNCERTAINTY. HAVE ALSO INSERTED SOME FOG
INTO THE KSBY/KPHF/KRIC TAF...BASED UPON RECENT RAINFALL AND PERSISTENCE.

SCTD SHOWERS/TSTMS WILL REMAIN POSSIBLE THRU EARLY FRI...BEFORE A
COLD FRONT SWEEPS THRU. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT
FOR FRI NGT THRU THE WEEKEND.

&&

.MARINE...
7 PM UPDATE...HAVE MADE SOME UPWARD ADJUSTMENTS TO WINDS/WAVES ON
THE CHESAPEAKE BAY...ESPECIALLY WESTERN SIDE...BASED UPON CURRENT
CONDITIONS AND LATEST HIGH RES MODEL OUTPUT. HRRR SEEMS TO HAVE A
GOOD HANDLE ON VERY SHORT TERM...AND HAVE USED IT AS PRIMARY WIND
GUIDANCE THROUGH 06Z THURSDAY. NO CHGS AFTER 06Z.

AFTERNOON DISCUSSION...LITTLE TO NO CHANGE TO ONGOING MARINE
FORECAST TONIGHT THROUGH MONDAY. WIND DIRECTIONS HAVE RETAINED
MORE OF A SE-S DIRECTION TODAY THAN PREVIOUSLY ANTICIPATED AND
HAVE INCREASED TO AROUND 10 KT. WINDS WILL CONTINUE TO SLOWLY VEER
TO THE S-SW OVERNIGHT AND INCREASE TWD 10-15 KT AS AN APPROACHING
TROUGH FROM THE OHIO VALLEY TIGHTENS THE PRESSURE GRADIENT OVER
THE WATERS. ALSO EXPECT SHOWER AND THUNDERSTORM CHANCES TO
INCREASE OVERNIGHT AS DECENT SHORTWAVE ENERGY/MOISTURE AND A JET
MAX ENHANCE LIFT/RAIN POTENTIAL. SHOWERS LINGER NEAR THE COAST
EARLY THURSDAY MORNING BUT THERE SHOULD BE A BRIEF REPRIEVE DURING
THE MID-LATE MORNING THROUGH EARLY AFTERNOON HOURS BEFORE
THUNDERSTORMS REGENERATE ALONG A COLD FRONT CROSSING THE WATERS
INTO THE EVENING. WINDS WILL BE PRIMARILY FROM THE SW AOB 15 KT ON
THURSDAY...THEN VEER TO THE W BY FRIDAY MORNING. SEAS WILL AVERAGE
2-3 FT AND WAVES ON CHES BAY WILL AVERAGE 1-2 FT.

THE FRONT STALLS ALONG THE CAROLINAS LATE THURSDAY NIGHT INTO AT
LEAST FRIDAY AFTERNOON...PROVIDING ADDITIONAL FOCUS/CHANCES FOR
AFTERNOON SHOWERS/STORMS ON FRIDAY. WINDS WILL START OUT FROM THE W
AND THEN VEER TO THE NW LATE IN THE AFTERNOON AS HIGH PRESSURE FROM
THE GREAT LAKES BEGINS TO SLIDE INTO THE REGION FROM THE NW. SPEEDS
STAY AOB 15 KT. THE FRONT FINALLY GETS PUSHED WELL SOUTH OF THE AREA
FRIDAY NIGHT BY THE LARGE-SCALE HIGH PRESSURE BUILDING INTO THE MID
ATLANTIC STATES THROUGHOUT THE WEEKEND. COOLER AND DRIER AIR WILL
ACCOMPANY THE HIGH AND QUICKLY BRING PRECIPITATION TO AN END FRIDAY
NIGHT. MODEL GUIDANCE WINDS CONTINUE TO KEEP WIND SPEEDS AOB 15 KT
AS THE COOLER AIR MOVES OVER WARMER WATERS FOR FRIDAY NIGHT INTO
SATURDAY. IN FACT...THEY ARE SHOWING AN INCREASE IN WINDS THROUGH
THE DAY ON SATURDAY AS THE COOL AIR FINALLY ARRIVES AND WINDS BECOME
NELY. WILL STILL MONITOR THE POTENTIAL FOR SCA CONDITIONS BUT NONE
ARE ANTICIPATED ATTM. SURFACE HIGH PRESSURE AND NE-E WINDS AOB 15 KT
SETTLE OVER THE WATERS THROUGHOUT THE WEEKEND. HIGH PRESSURE THEN
SLIDES SOUTHEAST OFF THE CAROLINA COAST ON MONDAY...SHIFTING WINDS
FROM E TO SE-S.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...ESS
NEAR TERM...ESS/MAS
SHORT TERM...ESS
LONG TERM...BMD
AVIATION...DAP/WRS
MARINE...BMD/WRS







AREA FORECAST DISCUSSION

NWS MARQUETTE MI

 132 AM EDT THU AUG 22 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 340 PM EDT WED AUG 21 2013

MAIN FOCUS OF THE FORECAST FOR TODAY IS THE DEVELOPING THUNDERSTORMS
ASSOCIATED WITH A COLD FRONT JUST STARTING TO MOVE INTO WESTERN
UPPER MICHIGAN.  THE COLD FRONT HAS BEEN MAKING IT/S WAY
ACROSS WESTERN LAKE SUPERIOR AND NORTHWEST WISCONSIN OVER THE
LAST FEW HOURS AND THERE WAS SOME CONCERN THAT THE STRATUS DECK
THAT DEVELOPED FROM THE FOG NEAR DULUTH WOULD LIMIT COME OF THE
CONVECTION. BUT THE FORCING FROM THE COLD FRONT COMBINED WITH
DIURNAL HEATING HAS BEGAN TO PRODUCE THUNDERSTORMS ALONG THE COLD
FRONT WITH SOME BECOMING FAIRLY STRONG AT THIS WRITTING. WITH A
VERY UNSTABLE ATMOSPHERE (MLCAPE VALUES ANALYZED FROM 2000-3000
J/KG DUE TO SFC DEWPOINTS IN THE UPPER 60S AND LOWER 70S)...THEY
SHOULDN/T HAVE MUCH DIFFICULTY CONTINUING THROUGH THE EARLY EVENING.
AS HAS BEEN MENTIONED OVER THE LAST COUPLE OF DAYS...0-6KM SHEAR
VALUES ARE A LITTLE MARGINAL...BUT LATEST RAP TRENDS SHOW VALUES
APPROACHING 30-35KTS RIGHT ALONG THE COLD FRONT. THIS SHOULD HELP
THE THUNDERSTORMS BECOME A LITTLE MORE TILTED AND BETTER ORGANIZED
OVER THE NEXT FEW HOURS. THINKING THAT THERE IS A DECENT CHANCE OF
THIS CONVECTION BECOMING LINEAR AND MOVING ACROSS MUCH OF UPPER
MICHIGAN LATE THIS AFTERNOON AND INTO THE EVENING. DAMAGING WIND IS
A DECENT THREAT WITH DCAPE VALUES AHEAD OF THE FRONT OF 800-1100
J/KG. WHERE THERE ARE STRONGER STORMS...HAIL IS ALSO A THREAT...BUT
IT WILL LIKELY BE MORE ISOLATED DUE TO THE HIGHER FREEZING LEVELS.
WITH THE BOUNDARIES OVER THE WEST AND LOWER LCL HEIGHTS FROM THE
LEFT OVER STRATUS...THERE COULD BE A ISOLATED TORNADO THREAT...BUT
SHOULD BE CONFINED TO THE LATE AFTERNOON. IN ADDITION...ANOTHER
BOUNDARY (AIDED BY EARLIER CLOUDS/SHOWERS THAT MOVED ACROSS NORTHERN
LAKE SUPERIOR) HAS SETUP FROM WEST TO EAST FROM ONTONAGON THROUGH
MARQUETTE COUNTY. SHOWERS/THUNDERSTORMS HAVE ALSO STARTED TO DEVELOP
ALONG THIS AND ARE SLIDING EAST. SPC HAS JUST ISSUED A SEVERE
THUNDERSTORM WATCH FOR MUCH OF UPPER MICHIGAN THROUGH 4Z. THE COLD
FRONT AND THUNDERSTORMS ARE EXPECTED TO EXIT INTO LAKE MICHIGAN
AROUND 06Z. PREVIOUS FORECAST HAD A GOOD HANDLE ON TIMING...SO ONLY
MADE MINOR ADJUSTMENTS.

THE REST OF THE NIGHT SHOULD BE DRY (DUE TO DRIER AIR SURGING IN
BEHIND THE COLD FRONT)...EVENTHOUGH A FAIRLY POTENT SHORTWAVE WILL
BE SLIDING SOUTHEAST ACROSS THE AREA FROM LAKE WINNIPEG. THIS
SHOULD LEAD TO MOSTLY CLEAR SKIES AND MUCH COOLER TEMPERATURES THAN
LAST NIGHT.

COOLER NORTHERLY FLOW WILL BE IN STORE FOR UPPER MICHIGAN ON
THURSDAY...AS HIGH PRESSURE APPROACHES THE AREA FROM THE UPPER
MISSISSIPPI VALLEY. 850MB TEMPS WILL BE AROUND 10C COOLER THAN
TODAY AND EXPECT A SIMILAR RESPONSE WITH THE HIGHS (IN THE 70S).
COOLEST TEMPERATURES WILL BE NEAR LAKE SUPERIOR...WHERE THE
NORTHERLY WINDS OFF THE LAKE WILL KEEP TEMPS RIGHT AROUND 70. A
SUNNY TO MOSTLY SUNNY SKY IS EXPECTED.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 340 PM EDT WED AUG 21 2013

NAM SHOWS A 500 MB RIDGE ACROSS THE ROCKIES AND CENTRAL PLAINS WITH
A TROUGH OVER THE ERN U.S. 00Z FRI. THE 500 MB RIDGE BUILDS INTO THE
CENTRAL PLAINS THIS FORECAST PERIOD WITH THE EDGE OF THE WESTERLIES
OVER THE AREA THIS FORECAST PERIOD. DID PUT IN SLIGHT CHANCE TO
CHANCE POPS IN THE FORECAST FOR THE WEST HALF FOR SAT AFTERNOON AS A
WARM FRONT HEADS TOWARDS THE AREA AND MOISTURE STARTS TO INCREASE.
OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST FOR
TEMPERATURES. LOOKS TO STAY WARM THROUGH THIS PERIOD.

IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB RIDGE OVER THE CENTRAL
U.S. SAT NIGHT INTO SUN. THE RIDGE REMAINS STATIONARY THROUGH THE
PERIOD WITH THE U.P. IN THE PERIPHERY OF THE RIDGE IN THE RING OF
FIRE SCENARIO WHERE ANY SHORTWAVE CAN SET OFF A ROUND OF
THUNDERSTORMS. WILL BE HARD TO TIME THESE SHORTWAVES AND EASIEST WAY
TO FORECAST THIS WOULD BE TO BROADBRUSH THIS FORECAST PERIOD WITH
CHANCE POPS EVEN THOUGH IT WILL NOT BE A TOTAL WASHOUT. TEMPERATURES
WILL STAY ABOVE NORMAL FOR THIS FORECAST PERIOD ALONG WITH
INCREASING HUMIDITY. ONLY PERIOD THAT LOOKS DRY IS WED WITH A FRONT
MOVING OUT OF THE AREA.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 131 AM EDT THU AUG 22 2013

BEHIND A COLD FRONT THAT HAS MOVED THROUGH THE AREA...
VFR CONDITIONS WILL PREVAIL THROUGH THE REST OF TONIGHT AND THURSDAY
AS HIGH PRESSURE BUILDS OVER THE AREA. THE EXCEPTION IS THAT SOME FOG
WILL BE PRESENT AT IWD AND SAW UNTIL THIS MORNING.

&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 340 PM EDT WED AUG 21 2013

A COLD FRONT CURRENTLY MOVING ACROSS CENTRAL LAKE SUPERIOR WILL
CONTINUE SOUTHEAST THIS EVENING AND LEAD TO NORTHERLY FLOW
(GENERALLY BELOW 15KTS) OVER THE LAKE FOR THE REST OF TONIGHT AND
INTO THURSDAY EVENING. HIGH PRESSURE THAT IS PRODUCING THE LIGHTER
WINDS WILL THEN SHIFT SOUTHEAST INTO THE LOWER GREAT LAKES AND
ALLOW WINDS TO SLOWLY INCREASE FROM THE SOUTH-SOUTHWEST FRIDAY INTO
THE WEEKEND. AT THIS POINT...WOULD EXPECT LAKE STABILITY FACTORS TO
KEEP WINDS AT OR BELOW 20KTS.

ONE FINAL ITEM TO MENTION IS IF THE SHOWERS/THUNDERSTORMS AFFECT
ENOUGH OF EASTERN LAKE SUPERIOR TO DEVELOP FOG. LEFT OUT AT THIS
POINT SINCE VISIBLE SATELLITE INDICATED THE FOG OVER NORTHERN LAKE
SUPERIOR HAS DISSIPATED AND THERE IS SOME UNCERTAINTY ON HOW FAR
THE RAIN WILL GET INTO EASTERN LAKE SUPERIOR.
&&

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

$$

SHORT TERM...SRF
LONG TERM...07
AVIATION...JLB
MARINE...SRF







AREA FORECAST DISCUSSION

NWS DETROIT/PONTIAC MI

 1203 AM EDT THU AUG 22 2013


.AVIATION...

//DISCUSSION...

CLOUDS CONTINUE TO THICKEN AND CIGS LOWER AHEAD OF AN APPROACHING
COLD FRONT OVERNIGHT. AN AREA OF SHOWERS AND THUNDERSTORMS CONTINUES
TO SLOWLY MARCH EAST...HOWEVER AS EVIDENCED BY RADAR THEY ARE HAVING
ISSUES MAINTAINING THEMSELVES AS THEY ENTER SOUTHEAST MICHIGAN. THE
GREATEST THREAT FOR THUNDERSTORMS CONTINUES TO BE THE NORTHERN
AIRPORTS...WITH MODELS CONTINUING TO INDICATE THIS ACTIVITY WILL
DROP OFF AS IT APPROACHES THE METRO AIRPORTS. THEREFORE WILL
CONTINUE THE PREVIOUS FORECAST OF NO THUNDER AT THE METRO AIRPORTS.
CIGS WITH THIS FRONT ARE EXPECTED TO BE AROUND 5KFT...HOWEVER VSBYS
COULD DROP TO MVFR IN RAIN SHOWERS AND THUNDERSTORMS. WINDS SHIFT TO
THE NORTH THURSDAY WITH PLENTY OF DRY AIR RETURNING THINGS TO VFR
AFTER THE RAIN.

FOR DTW...BEST THUNDERSTORM CHARACTERISTICS APPEAR TO BE FURTHER
NORTH...SO WILL CONTINUE TO LEAVE TS OUT OF THE TAFS THIS PERIOD.
WILL UPDATE WITH AMD IF NEEDED...BUT DTW WILL LIKELY DROP TO 4SM
WITH STRONGEST SHOWERS.

//DTW THRESHOLD THREATS...

* MEDIUM CONFIDENCE OF CEILINGS BELOW 5000 FEET AFTER 10Z TONIGHT.

&&

.PREV DISCUSSION...ISSUED 339 PM EDT WED AUG 21 2013

SHORT TERM...TONIGHT

VIS SATELLITE AND RADAR SHOW VERY SMALL AREAS OF SHOWERS ALONG AN
AREA OF MOISTURE CONVERGENCE FROM JYM TO PTK. THIS WAS DEPICTED WELL
WITH THE HRRR AS A DIURNAL CONVECTIVE SHOWER EVENT THAT WILL SWING
EAST AND SOUTH...DYING WITH THE LOSS OF DAYTIME HEATING. 20-30 POP
GRIDS WERE UPDATED EARLIER TO INCLUDE THIS CHANCE...WHICH WILL END
NLT 00Z.

CLOUDS AND PRECIP CHANCES INCREASE FROM NW TO SE TONIGHT AS A COLD
FRONT APPROACHES FROM THE NORTHWEST. THERE WILL  BE SOME ELEVATED
INSTABILITY...ESPECIALLY NORTH OF I-69 OVERNIGHT AS LI/S ARE -2 OR
-3 AND ABOUT 1000 J/KG OF CAPE IS PRESENT ABOVE 800 MB. WINDS WILL
ALSO VEER AND INCREASE WITH HEIGHT IN THE ELEVATED LAYER
OVERNIGHT...LEADING TO HIGHER POPS TO INCLUDE THUNDER IN THE
FORECAST. THESE CONDITIONS WILL SWING SOUTHEASTWARD THROUGH THE
STATE...BUT HIGHER PW/S (2.0 INCHES) AND LESS INSTABILITY BRING THE
FORECAST TO LOWER THUNDER CHANCES SOUTH OF M-59.

LONG TERM...THURSDAY THROUGH TUESDAY

A WELL-DEFINED 110KT JET IS EVIDENT ALONG THE US/CANADA BORDER THIS
AFTERNOON AS THE UPPER GRADIENT TIGHTENS BETWEEN THE EXPANSIVE
WESTERN U.S. RIDGE AND SHORTWAVE ENERGY DIGGING INTO SOUTHEAST
SASKATCHEWAN AND SOUTHWEST MANITOBA. MESOANALYSIS REVEALS AN
ORGANIZING LOW-LEVEL BAROCLINIC ZONE ASSOCIATED WITH THIS JET THAT
IS BEGINNING TO FEEL ITS WAY SOUTHEAST AS THE LARGE SCALE TROUGH
OVER CENTRAL AND EASTERN CANADA BEGINS TO SWEEP ACROSS THE GREAT
LAKES. RELATIVELY LITTLE HAS CHANGED WITH REGARD TO FORECAST
REASONING. INITIALLY, SOME REMNANT SHOWERS WILL BE POSSIBLE IN
ADVANCE OF THE FRONT IN ASSOCIATION WITH ANY UPSTREAM DEVELOPMENT
OVER WISCONSIN THIS EVENING, ALTHOUGH CONFIDENCE IS NOT PARTICULARLY
HIGH IN THE DEGREE OF COVERAGE EARLY IN THE PERIOD GIVEN THE LACK OF
LARGE SCALE SUPPORT. STILL, EITHER WEAKLY ORGANIZED RIGHT ENTRANCE
SUPPORT, A CONVECTIVELY ENHANCED WAVE EMANATING OUT OF UPSTREAM
ACTIVITY, OR A COMBINATION OF BOTH, STILL WARRANT A CONTINUATION OF
LIKELY POPS ACROSS MUCH OF THE AREA DURING THE FIRST HALF OF THE
DAY.

UNCERTAINTY FURTHER INCREASES FOR THURSDAY AFTERNOON AS BOUNDARY
LAYER RECOVERY WILL BE STRONGLY DEPENDENT ON CLOUD COVER AND
DURATION OF MORNING SHOWERS. THE NAM/GFS REPRESENT THE AGGRESSIVE
SIDE OF THE ENVELOPE WITH UP TO 3000 J/KG SBCAPE DEVELOPING BY MID
AFTERNOON WHEREAS THE GENERAL CONSENSUS OF BOTH HIGHER RESOLUTION
GUIDANCE SUCH AS THE NMM/ARW AS WELL AS THE GEM/ECMWF ALLOW HIGH
PRESSURE TO AGGRESSIVELY BUILD IN WITH LITTLE MORE THAN A LOW
COVERAGE OF AFTERNOON SHOWERS TO SHOW FOR THE FROPA. GIVEN THE
DEGREE OF UNCERTAINTY, FELT IT PRUDENT TO TAPER POPS BACK INTO THE
HIGH CHANCE CATEGORY ESSENTIALLY EVERYWHERE ALONG/NORTH OF I-94,
WHICH REFLECTS THE LATEST FORECAST REASONING BUT STILL LEAVES ROOM
FOR ADJUSTMENT IN EITHER DIRECTION AS NEW DATA BECOMES AVAILABLE.
FOR FAR SOUTHERN AREAS, ENOUGH RECOVERY WILL BE POSSIBLE TO SUPPORT
A PULSE SEVERE THREAT IMMEDIATELY AHEAD OF THE FRONT, BUT WITH THE
BETTER SHEAR LAGGING BEHIND, THE THREAT FOR ORGANIZED SEVERE WEATHER
REMAINS LOW. TEMPERATURES WILL FALL BACK TO NEAR 80 FOR THE WEEKEND
AS COOLER AND DRIER AIR FILTERS INTO SOUTHEAST MI IN THE WAKE OF THE
FRONT AND HIGH PRESSURE SETTLES OVER THE NORTHEASTERN UNITED STATES.

THERE WILL BE NUMEROUS CHANCES FOR THUNDERSTORMS NEXT WEEK AS THE
CWA WILL BE POSITIONED ALONG THE NE PERIPHERY OF THE BUILDING 595DM
RIDGE OVER THE CENTRAL U.S. WHILE REMAINING IN CLOSE PROXIMITY TO
PREVAILING WESTERLY FLOW. THIS WILL SET THE STAGE FOR MULTIPLE
CONVECTIVE COMPLEXES TO AFFECT SOME OR ALL OF THE REGION. INITIAL
EXPECTATIONS ARE THEREFORE FOR THUNDERSTORM ACTIVITY IN THE VICINITY
TO HELP KEEP TEMPERATURES IN CHECK, BUT WITH H5 HEIGHTS IN THE
585-588DM RANGE AND H85 TEMPS NEAR 20C, THE POTENTIAL FOR HIGHS TO
REACH INTO THE 90S WILL EXIST ON BASICALLY ANY DAY FROM MONDAY
ONWARD.

MARINE...

A PRESSURE GRADIENT BETWEEN HIGH PRESSURE IN THE MID-ATLANTIC AND
LOW PRESSURE OVER HUDSON BAY WILL PROVIDE INCREASED SW WINDS
TONIGHT. AIR TEMPERATURES WILL STAY PRETTY WARM UNTIL THE COLD FRONT
SWINGS THROUGH EARLY THURSDAY...SO THERE IS NOT MUCH INSTABILITY
OVER THE LAKES UNTIL THEN. OFFSHORE WINDS WILL BECOME MORE ONSHORE
LATE THURSDAY AND WILL HELP INCREASE WAVE HEIGHTS ALONG THE THUMB`S
SHORE TO 3 FEET. WILL WATCH FOR SMALLCRAFT CONDITIONS NEXT FORECAST
PERIOD...BUT IN THE MEANTIME SIG/MAX WAVES SHOULD STAY MANAGEABLE.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....DG
SHORT TERM...MM
LONG TERM....JVC
MARINE.......MM


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).







AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 1056 PM CDT FRI AUG 23 2013

.SYNOPSIS...
ISSUED AT 326 PM CDT FRI AUG 23 2013

RAP H5 ANALYSIS THIS AFTERNOON SHOWS HEIGHT RISES DOMINATING THE
CENTRAL CONUS...AS THE UPPER HIGH THAT WILL BE BRINGING US THE HEAT
WAVE COME SUNDAY IS STARTING TO STRENGTHEN OVER KANSAS...WITH THE
RIDGE AXIS BUILDING NORTH INTO THE RED RIVER VALLEY. WATER VAPOR
SHOWS A COUPLE OF WEAK WAVE ACROSS THE DAKOTAS THAT WILL BE
ROUNDING THE TOP OF THE RIDGE TONIGHT.

AT THE SFC...HIGH PRESSURE HAS NOW MOVED INTO THE GREAT LAKES...WITH
RETURN FLOW BECOMING ESTABLISHED ACROSS THE AREA. FRONT THAT SETTLED
ALONG THE IOWA BORDER THURSDAY HAS COMPLETELY WASHED OUT...WITH THE
HIGH DEWPOINTS THAT HAD POOLED OVER IOWA LAST NIGHT NOW SURGING
NORTH ON THE SOUTH WINDS...WITH CU FIELD MOVING NORTH OUT OF SRN MN
ALSO DENOTING WHERE DEWPOINT GO FROM THE 50S BACK UP TO THE UPPER
60S TO AROUND 70.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 326 PM CDT FRI AUG 23 2013

MAIN CONCERN RIGHT OFF THE BAT WILL BE THE POTENTIAL FOR
THUNDERSTORMS WITHIN THE NEXT COUPLE OF HOURS OVER SW MN. 19Z SPC
MESOANALYSIS SHOWS A BUBBLE OF 3000-4000 J/KG OF MLCAPE HAS
DEVELOPED IN THE MN/SD/NEB/IA BORDERS REGION. IN ADDITION...LLJ AND
ASSOCIATED MOISTURE TRANSPORT IS BEGINNING TO INCREASE ACROSS NE NEB
AND SE SODAK. IN THIS REGION...THE HRRR ALONG WITH ALL MEMBERS OF
THE 15Z HOPWRF SHOW AN AREA OF SCT TSTMS DEVELOPING AROUND SIOUX
FALLS...THEN DRIFTING NNE TOWARD THE UPPER MN RIVER VALLEY. HAVE
SOME ISO THUNDER WORDING OUT THERE BETWEEN 22 AND 02Z AS A RESULT.
INTERESTINGLY...BOTH THE HRRR AND HOPWRF SHOW THIS ACTIVITY BEING
DIURNALLY DRIVEN...WITH IT MOSTLY DISSIPATED BY 03Z.

FOR TONIGHT...STILL LOTS OF UNCERTAINTY AS TO HOW THINGS WILL UNFOLD
FOR PRECIP AS WE GET INTO A WAA REGIME...BUT IT IS STARTING TO LOOK
UNLIKELY THAT MUCH IS SEEN. LOOKING AT TEMP/MOISTURE ADVECTION
AROUND THE H7 LEVEL...THE GFS/NAM SHOW TWO AREAS OF ENHANCED FORCING
IN THE REGION TONIGHT...ONE DOWN ACROSS IOWA AND THE OTHER UP ACROSS
NRN MN. THE 23.12 ECMWF ONLY HAS THE NRN FORCING SOURCE. GIVEN THAT
THE NOSE OF THE LLJ LOOKS TO BE DIRECTED INTO NRN MN...CONFIDENCE IS
HIGHEST IN SOMETHING TRACKING ACROSS NRN MN /PER THE NMM AND SPCWRF
REFLECTIVITY FORECASTS/. HOWEVER...GIVEN THE BROAD ZONE OF
WAA/MOISTURE TRANSPORT MOVING ACROSS THE AREA CAN NOT RULE OUT
GETTING SOME AT LEAST SCT SHRA/TSRA AS THE LLJ WORKS ACROSS THE AREA
OVERNIGHT INTO SATURDAY MORNING. FOR THE POP GRIDS...DID NUDGE THEM
DOWN SOME...AND ALSO SLOWED DOWN THE ERN PROGRESSION OF
THINGS...CLOSER TO A NAM TIMING. DURING THE DAY ON SATURDAY...A
STRONG CAPPING INVERSION WILL BE MOVING IN...WHICH SHOULD SHUT DOWN
THE PRECIP FOR MOST OF MN BY THE AFTERNOON...WITH CHANCES LINGERING
ACROSS WRN WI.

LAST QUESTION MARK FOR THIS FORECAST IS HOW WARM DO WE GET ON
SATURDAY. THIS WILL DEPEND HIGHLY ON HOW QUICKLY SKIES CAN CLEAR OUT
FROM WEST TO EAST FROM THE MORNING INTO THE AFTERNOON. ERN MN/WRN WI
WILL LIKELY ENJOY THE CLOUD COVER FOR A GOOD CHUNK OF THE
DAY...WHICH SHOULD HELP HOLD HIGHS BACK INTO LOW/MID 80S...THOUGH
WITH DEWPS UP AROUND 70...IT WON`T EXACTLY FEEL COMFORTABLE. OUT IN
WRN MN...CLOUDS SHOULD CLEAR OUT EARLY ENOUGH TO ALLOW THE RETURN OF
90S...THOUGH DEPENDING ON HOW QUICKLY THE SUN ARRIVES...THE WEST
COULD SEE HIGHS ANYWHERE FROM THE UPPER 80S /MORE CLOUDS/ TO THE
UPPER 90S /VERY LITTLE CLOUD COVER/.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 326 PM CDT FRI AUG 23 2013

MAIN CONCERN IN THE EXTENDED IS WELL ADVERTISED HEAT WAVE THAT IS
FORECAST TO BRING NEAR RECORD TEMPERATURES BEGINNING SUNDAY...AND
LASTING THROUGH AT LEAST THE MIDDLE OF THIS WEEK. THE LONG DURATION
OF THIS HEAT...WITH THE WARM OVERNIGHT MIN TEMPS IS THE REASON
BEHIND THE EXCESSIVE HEAT WATCH THAT WAS ISSUED EARLIER THIS
MORNING. MASS TEMPERATURE FIELDS FROM THE H925/H850 LAYER...TOGETHER
WITH THE 500MB HEIGHTS SUPPORT THIS HEAT WATCH...BUT IF ANY DEBRIS
CLOUDS FROM AN OVERNIGHT MCS SPREAD ACROSS THE REGION...OR IF THE
MCS ITSELF BUILDS TO THE SOUTH AS INDICATED BY THE GFS AND ECMWF
23.12...THEN FORECAST MAX TEMPERATURES WILL BE OVERDONE BY SEVERAL
DEGREES.

AT THE START OF THE PERIOD LOW LEVEL WARM AIR ADVECTION WITH
SOUTHWEST FLOW WILL BE WELL ESTABLISHED ACROSS THE CWA...SO HAVE
RAISED MIN TEMPERATURES SATURDAY NIGHT/SUNDAY MORNING. ALSO HAVE
INCREASED THE WINDS HIGHER THAN GUIDANCE AS WELL...ESPECIALLY ALONG
THE UPPER MINNESOTA RIVER VALLEY WHERE THE DOWNSLOPE COMPONENT OFF
THE BUFFALO RIDGE WILL ADD A FEW EXTRA KNOTS. THESE WARMER LOW
TEMPERATURES WILL TRANSLATE INTO AFTERNOON HIGHS IN THE MID TO UPPER
90S ON SUNDAY AS THE BOUNDARY LAYER MIXES UP TO 850MB AS SHOWN VIA
THE BUFR SOUNDINGS. ANOTHER RESULT OF THIS DEEP MIXING WILL BE
DEWPOINT DROPPING INTO THE MID 60S DURING THE AFTERNOON. IF THE NAM
23.12 VERIFIES...DEWPOINTS COULD FALL INTO THE UPPER 50S AT A FEW
LOCATIONS. USED THE MIXDOWN TOOL TOGETHER WITH BIAS CORRECTED MODEL
BLEND TO POPULATE BOTH T AND TD ON SUNDAY. LOOKING AHEAD...INCREASED
LOW LEVEL MOISTURE WILL BRING HIGHER TDS ON MONDAY WITH AFTERNOON
MAX TEMPS ONCE AGAIN IN THE MID TO UPPER 90S.

THIS WILL BE THE TREND THROUGH THE EXTENDED...WITH THE ONCE CAVEAT
BEING THE CONVECTIVE POTENTIAL. AS ALLUDED TO EARLIER...OVERNIGHT
CONVECTION WILL DEVELOP AS SHORTWAVES PERIODICALLY ROUND THE BASE
OF THE UPPER LEVEL RIDGE ACROSS THE INTERNATIONAL BORDER. THE 23.12Z
GFS AND ECMWF DEVELOP CONVECTION ACROSS THE ARROWHEAD SATURDAY
NIGHT...AND OVER LAKE SUPERIOR SUNDAY NIGHT...WITH THE SECOND
FEATURE BUILDING SOUTHWEST AS IT IS FED BY THE LOW LEVEL JET. A
SHORTWAVE THAT IS CURRENTLY LOCATED OFF THE BAJA PENINSULA IS
FORECAST TO MOVE ACROSS THE UPPER MIDWEST MONDAY NIGHT...AND PUSH A
FRONTAL BOUNDARY THROUGH CENTRAL MN AND NORTHERN WI. THIS ALSO COULD
GIVE SOME REPRIEVE FROM THE HEAT BY MID WEEK...BUT CONFIDENCE IN THE
SOUTHERN EXTEND OF THIS FRONTAL BOUNDARY IS LOW AT THIS TIME.
THEREFORE FEEL THE POTENTIAL FOR DANGEROUS HEAT WAVE MERITS THE
EXCESSIVE HEAT WATCH IN CENTRAL MN AND FAR WESTERN WI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1046 PM CDT FRI AUG 23 2013

AM EXPECTING PREVAILING VFR BUT THERE MAY BE SOME ISSUES
WITH -SHRA MOVING IN FROM THE WSW LATE OVERNIGHT THRU MUCH OF THE
DAY TMRW. WEAK FORCING CONTINUES TO BE ADVERTISED ON THE SHORT-
TERM MODELS FOR LIGHT SHOWERS IN SW MN TO DEVELOP IN THE 09Z-12Z
RANGE...BUT SOME ALSO ADVERTISE PRECIP AT THE INITIAL 06Z HOUR SO
CONFIDENCE IS NOT HIGH BY ANY MEANS FOR SHOWING PRECIP IN THE
TAFS. HAVE MAINTAINED A WINDOW OF VCSH AT ALL TAF SITES SINCE
PRECIP CHCS ARE ONLY IN THE 30-40 PERCENT RANGE. ANY PRECIP THAT
DOES OCCUR...AM NOT LOOKING FOR ANYTHING OVERLY SIGNIFICANT.
OTHERWISE...THE MOST SIGNIFICANT ELEMENT WILL BE WINDS. SE WINDS
WILL LOCK IN BY DAYBREAK AND INCREASE SIGNIFICANTLY BETWEEN A
DEVELOPING LOW PRES AREA OVER THE DAKOTAS AND EXITING HIGH
PRESSURE OVER THE GREAT LAKES. SUSTAINED WINDS WILL INCRS TO 15-20
KT WITH GUSTS UPWARDS OF 30 KT FOR MUCH OF THE DAY TMRW. WINDS
WILL SETTLE DOWN SLIGHTLY AROUND DUSK...BUT SUSTAINED WINDS ARE
STILL GENERALLY EXPECTED TO BE IN THE 10-15 KT RANGE.

KMSP...VFR EXPECTED THROUGHOUT. SMALL CHANCE OF SEEING DAYBREAK
-SHRA BUT NOTHING SIGNIFICANT EXPECTED. CIGS IN THE 5-8 KFT RANGE
MAY DEVELOP...BUT NOTHING LOWER THAN THAT EXPECTED...AND THEN
MID- AND HIGH-LEVEL CLOUDS LATE IN THE DAY. MAIN ISSUE WILL BE
STRONG SE TO S WIND SPEEDS...STARTING AROUND OR SHORTLY AFTER
DAYBREAK AND LASTING THROUGH MUCH OF THE DAY.

/OUTLOOK FOR KMSP/
SUN...VFR. SW WIND 10-15 G25 KT.
MON...VFR. SW WIND 10 KT.
TUE...VFR. SW WIND 5 KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
     EVENING FOR MNZ047>051-054>070-073>078-082>085-091>093.

WI...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
     EVENING FOR WIZ023-024.

&&

$$

SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...JRB
AVIATION...JPC







AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 734 PM CDT FRI AUG 23 2013

.SYNOPSIS...
ISSUED AT 326 PM CDT FRI AUG 23 2013

RAP H5 ANALYSIS THIS AFTERNOON SHOWS HEIGHT RISES DOMINATING THE
CENTRAL CONUS...AS THE UPPER HIGH THAT WILL BE BRINGING US THE HEAT
WAVE COME SUNDAY IS STARTING TO STRENGTHEN OVER KANSAS...WITH THE
RIDGE AXIS BUILDING NORTH INTO THE RED RIVER VALLEY. WATER VAPOR
SHOWS A COUPLE OF WEAK WAVE ACROSS THE DAKOTAS THAT WILL BE
ROUNDING THE TOP OF THE RIDGE TONIGHT.

AT THE SFC...HIGH PRESSURE HAS NOW MOVED INTO THE GREAT LAKES...WITH
RETURN FLOW BECOMING ESTABLISHED ACROSS THE AREA. FRONT THAT SETTLED
ALONG THE IOWA BORDER THURSDAY HAS COMPLETELY WASHED OUT...WITH THE
HIGH DEWPOINTS THAT HAD POOLED OVER IOWA LAST NIGHT NOW SURGING
NORTH ON THE SOUTH WINDS...WITH CU FIELD MOVING NORTH OUT OF SRN MN
ALSO DENOTING WHERE DEWPOINT GO FROM THE 50S BACK UP TO THE UPPER
60S TO AROUND 70.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 326 PM CDT FRI AUG 23 2013

MAIN CONCERN RIGHT OFF THE BAT WILL BE THE POTENTIAL FOR
THUNDERSTORMS WITHIN THE NEXT COUPLE OF HOURS OVER SW MN. 19Z SPC
MESOANALYSIS SHOWS A BUBBLE OF 3000-4000 J/KG OF MLCAPE HAS
DEVELOPED IN THE MN/SD/NEB/IA BORDERS REGION. IN ADDITION...LLJ AND
ASSOCIATED MOISTURE TRANSPORT IS BEGINNING TO INCREASE ACROSS NE NEB
AND SE SODAK. IN THIS REGION...THE HRRR ALONG WITH ALL MEMBERS OF
THE 15Z HOPWRF SHOW AN AREA OF SCT TSTMS DEVELOPING AROUND SIOUX
FALLS...THEN DRIFTING NNE TOWARD THE UPPER MN RIVER VALLEY. HAVE
SOME ISO THUNDER WORDING OUT THERE BETWEEN 22 AND 02Z AS A RESULT.
INTERESTINGLY...BOTH THE HRRR AND HOPWRF SHOW THIS ACTIVITY BEING
DIURNALLY DRIVEN...WITH IT MOSTLY DISSIPATED BY 03Z.

FOR TONIGHT...STILL LOTS OF UNCERTAINTY AS TO HOW THINGS WILL UNFOLD
FOR PRECIP AS WE GET INTO A WAA REGIME...BUT IT IS STARTING TO LOOK
UNLIKELY THAT MUCH IS SEEN. LOOKING AT TEMP/MOISTURE ADVECTION
AROUND THE H7 LEVEL...THE GFS/NAM SHOW TWO AREAS OF ENHANCED FORCING
IN THE REGION TONIGHT...ONE DOWN ACROSS IOWA AND THE OTHER UP ACROSS
NRN MN. THE 23.12 ECMWF ONLY HAS THE NRN FORCING SOURCE. GIVEN THAT
THE NOSE OF THE LLJ LOOKS TO BE DIRECTED INTO NRN MN...CONFIDENCE IS
HIGHEST IN SOMETHING TRACKING ACROSS NRN MN /PER THE NMM AND SPCWRF
REFLECTIVITY FORECASTS/. HOWEVER...GIVEN THE BROAD ZONE OF
WAA/MOISTURE TRANSPORT MOVING ACROSS THE AREA CAN NOT RULE OUT
GETTING SOME AT LEAST SCT SHRA/TSRA AS THE LLJ WORKS ACROSS THE AREA
OVERNIGHT INTO SATURDAY MORNING. FOR THE POP GRIDS...DID NUDGE THEM
DOWN SOME...AND ALSO SLOWED DOWN THE ERN PROGRESSION OF
THINGS...CLOSER TO A NAM TIMING. DURING THE DAY ON SATURDAY...A
STRONG CAPPING INVERSION WILL BE MOVING IN...WHICH SHOULD SHUT DOWN
THE PRECIP FOR MOST OF MN BY THE AFTERNOON...WITH CHANCES LINGERING
ACROSS WRN WI.

LAST QUESTION MARK FOR THIS FORECAST IS HOW WARM DO WE GET ON
SATURDAY. THIS WILL DEPEND HIGHLY ON HOW QUICKLY SKIES CAN CLEAR OUT
FROM WEST TO EAST FROM THE MORNING INTO THE AFTERNOON. ERN MN/WRN WI
WILL LIKELY ENJOY THE CLOUD COVER FOR A GOOD CHUNK OF THE
DAY...WHICH SHOULD HELP HOLD HIGHS BACK INTO LOW/MID 80S...THOUGH
WITH DEWPS UP AROUND 70...IT WON`T EXACTLY FEEL COMFORTABLE. OUT IN
WRN MN...CLOUDS SHOULD CLEAR OUT EARLY ENOUGH TO ALLOW THE RETURN OF
90S...THOUGH DEPENDING ON HOW QUICKLY THE SUN ARRIVES...THE WEST
COULD SEE HIGHS ANYWHERE FROM THE UPPER 80S /MORE CLOUDS/ TO THE
UPPER 90S /VERY LITTLE CLOUD COVER/.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 326 PM CDT FRI AUG 23 2013

MAIN CONCERN IN THE EXTENDED IS WELL ADVERTISED HEAT WAVE THAT IS
FORECAST TO BRING NEAR RECORD TEMPERATURES BEGINNING SUNDAY...AND
LASTING THROUGH AT LEAST THE MIDDLE OF THIS WEEK. THE LONG DURATION
OF THIS HEAT...WITH THE WARM OVERNIGHT MIN TEMPS IS THE REASON
BEHIND THE EXCESSIVE HEAT WATCH THAT WAS ISSUED EARLIER THIS
MORNING. MASS TEMPERATURE FIELDS FROM THE H925/H850 LAYER...TOGETHER
WITH THE 500MB HEIGHTS SUPPORT THIS HEAT WATCH...BUT IF ANY DEBRIS
CLOUDS FROM AN OVERNIGHT MCS SPREAD ACROSS THE REGION...OR IF THE
MCS ITSELF BUILDS TO THE SOUTH AS INDICATED BY THE GFS AND ECMWF
23.12...THEN FORECAST MAX TEMPERATURES WILL BE OVERDONE BY SEVERAL
DEGREES.

AT THE START OF THE PERIOD LOW LEVEL WARM AIR ADVECTION WITH
SOUTHWEST FLOW WILL BE WELL ESTABLISHED ACROSS THE CWA...SO HAVE
RAISED MIN TEMPERATURES SATURDAY NIGHT/SUNDAY MORNING. ALSO HAVE
INCREASED THE WINDS HIGHER THAN GUIDANCE AS WELL...ESPECIALLY ALONG
THE UPPER MINNESOTA RIVER VALLEY WHERE THE DOWNSLOPE COMPONENT OFF
THE BUFFALO RIDGE WILL ADD A FEW EXTRA KNOTS. THESE WARMER LOW
TEMPERATURES WILL TRANSLATE INTO AFTERNOON HIGHS IN THE MID TO UPPER
90S ON SUNDAY AS THE BOUNDARY LAYER MIXES UP TO 850MB AS SHOWN VIA
THE BUFR SOUNDINGS. ANOTHER RESULT OF THIS DEEP MIXING WILL BE
DEWPOINT DROPPING INTO THE MID 60S DURING THE AFTERNOON. IF THE NAM
23.12 VERIFIES...DEWPOINTS COULD FALL INTO THE UPPER 50S AT A FEW
LOCATIONS. USED THE MIXDOWN TOOL TOGETHER WITH BIAS CORRECTED MODEL
BLEND TO POPULATE BOTH T AND TD ON SUNDAY. LOOKING AHEAD...INCREASED
LOW LEVEL MOISTURE WILL BRING HIGHER TDS ON MONDAY WITH AFTERNOON
MAX TEMPS ONCE AGAIN IN THE MID TO UPPER 90S.

THIS WILL BE THE TREND THROUGH THE EXTENDED...WITH THE ONCE CAVEAT
BEING THE CONVECTIVE POTENTIAL. AS ALLUDED TO EARLIER...OVERNIGHT
CONVECTION WILL DEVELOP AS SHORTWAVES PERIODICALLY ROUND THE BASE
OF THE UPPER LEVEL RIDGE ACROSS THE INTERNATIONAL BORDER. THE 23.12Z
GFS AND ECMWF DEVELOP CONVECTION ACROSS THE ARROWHEAD SATURDAY
NIGHT...AND OVER LAKE SUPERIOR SUNDAY NIGHT...WITH THE SECOND
FEATURE BUILDING SOUTHWEST AS IT IS FED BY THE LOW LEVEL JET. A
SHORTWAVE THAT IS CURRENTLY LOCATED OFF THE BAJA PENINSULA IS
FORECAST TO MOVE ACROSS THE UPPER MIDWEST MONDAY NIGHT...AND PUSH A
FRONTAL BOUNDARY THROUGH CENTRAL MN AND NORTHERN WI. THIS ALSO COULD
GIVE SOME REPRIEVE FROM THE HEAT BY MID WEEK...BUT CONFIDENCE IN THE
SOUTHERN EXTEND OF THIS FRONTAL BOUNDARY IS LOW AT THIS TIME.
THEREFORE FEEL THE POTENTIAL FOR DANGEROUS HEAT WAVE MERITS THE
EXCESSIVE HEAT WATCH IN CENTRAL MN AND FAR WESTERN WI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 713 PM CDT FRI AUG 23 2013

OVERALL..AM EXPECTING PREVAILING VFR BUT THERE MAY BE SOME ISSUES
WITH -SHRA MOVING IN FROM THE WSW LATE OVERNIGHT THRU MUCH OF THE
DAY TMRW. WEAK FORCING CONTINUES TO BE ADVERTISED ON THE SHORT-
TERM MODELS FOR SHOWERS IN SW MN TO DEVELOP IN THE 09Z-12Z
RANGE...BUT THEY ALSO ALL ADVERTISE PRECIP AT THE CURRENT 00Z HOUR
SO CONFIDENCE IS NOT HIGH BY ANY MEANS FOR SHOWING PRECIP IN THE
TAFS. HAVE INHERITED A WINDOW OF VCSH AT MOST TAF SITES AND SINCE
PRECIP CHCS ARE ONLY IN THE 30-40 PERCENT RANGE...HAVE CARRIED
THIS OVER TO ALL TAF SITES. ANY PRECIP THAT DOES OCCUR...AM NOT
LOOKING FOR ANYTHING OVERLY SIGNIFICANT...SO LATER TAF ISSUANCES
CAN ADJUST TRENDS AS NEEDED. OTHERWISE...THE MOST SIGNIFICANT
ELEMENT WILL BE WINDS. SE WINDS WILL LOCK IN BY DAYBREAK AND
INCREASE SIGNIFICANTLY BETWEEN A DEVELOPING LOW PRES AREA OVER THE
DAKOTAS AND EXITING HIGH PRESSURE OVER THE GREAT LAKES. SUSTAINED
WINDS WILL INCRS TO 15-20 KT WITH GUSTS UPWARDS OF 30 KT FOR MUCH
OF THE DAY TMRW.

KMSP...VFR EXPECTED THROUGHOUT. MAY SEE SOME DAYBREAK -SHRA BUT
NOTHING SIGNIFICANT EXPECTED. CIGS IN THE 5-8 KFT RANGE MAY
DEVELOP...BUT NOTHING LOWER THAN THAT EXPECTED...AND THEN SEVERAL
SCT LAYERS LATE IN THE DAY. MAIN ISSUE WILL BE STRONG SE WIND
SPEEDS...STARTING AROUND OR SHORTLY AFTER DAYBREAK AND LASTING
THROUGH MUCH OF THE DAY.

/OUTLOOK FOR KMSP/
SUN...VFR. SW WIND 10-15 G25 KT.
MON...VFR. SW WIND 10 KT.
TUE...VFR. SW WIND 5 KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
     EVENING FOR MNZ047>051-054>070-073>078-082>085-091>093.

WI...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH WEDNESDAY
     EVENING FOR WIZ023-024.

&&

$$

SYNOPSIS...MPG
SHORT TERM...MPG
LONG TERM...JRB
AVIATION...JPC







AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 1222 PM CDT THU AUG 22 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT THU AUG 22 2013

SHORT TERM TRENDS POINT TO SOME ISOLATED THUNDER LIFTING AS FAR
NORTH AS DECAYING FRONTAL BOUNDARY...WITHIN INSTABILITY AXIS AND
NORTHERN PERIPHERY OF COMPLEX OVER IOWA. WILL HAVE TO INCLUDE THIS
FOR MUCH OF THE MORNING HOURS ANYWAY.

THIS CONVECTION IS BEING FORCED BY SOME WEAK LAYERED FRONTOGENESIS.
THIS IS PROGGED BE THE HRRR AND MEMBER 1 AND 2 OF THE HOPWRF TO
GRADUALLY WEAKEN AND DROP FARTHER SOUTH AS DRIER AIR TRIES TO DROP
SOUTHWEST ERODING THE BOUNDARY.  SHOULD SEE GRADUAL DRYING THEN INTO
THE AFTERNOON...AS SURFACE HIGH DROPS SOUTHEAST INTO TONIGHT.
CLOUDS SHOULD GIVE WAY TO CLEARING DURING THE DAY...AND CONTINUE
THIS TREND THROUGH THE NIGHT.  TEMPERATURES COOL A BIT TO THE LOWER
AND MIDDLE 80S OVER MOST OF THE AREA TODAY.  LOWS SHOULD COOL TO
AROUND 50 EAST AND AROUND 60 TO THE SOUTHWEST TONIGHT...AS DRIER AIR
MOVES ACROSS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 410 AM CDT THU AUG 22 2013

THE MAIN WEATHER HEADLINE IN THE LONG TERM PORTION OF THE FORECAST
WILL BE BUILDING HEAT...AS MID LEVEL HEIGHTS GRADUALLY RISE IN
CONJUNCTION WITH THE EXTENSIVE RIDGE OVER THE CENTRAL CONUS. THE RETURN
OF THE HOT WEATHER WILL BE MET WITH THE ARRIVAL OF A WARM FRONT.
HAVE RETAINED 20-40 POPS FOR FRIDAY NIGHT INTO SATURDAY MORNING AS
THE AFOREMENTIONED FRONT BEGINS TO LIFT ACROSS THE AREA. ALTHOUGH
THE ORIENTATION OF THE 35-40KT PROGGED LLJ IS NOT IDEAL FOR
WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...INDICATIONS ARE THAT
IT SHOULD BE ADEQUATE FROM CENTRAL MN INTO WEST CENTRAL WI TO
WARRANT LOW CHANCE POPS CENTERED BETWEEN 06Z AND 18Z SATURDAY.
AFTER THAT...OTHER THAN A FEW STRAY SHOWERS/TS NORTH OF INTERSTATE
94 CLOSER TO THE BOUNDARY...MOSTLY DRY CONDITIONS ARE EXPECTED
THROUGH MONDAY AS THE WARM FRONT LIFTS INTO NORTHERN MN. AS THIS
OCCURS...TEMPERATURES WILL MODERATE INTO THE LOW/MID 90S FOR
SUNDAY THROUGH TUESDAY AS DEWPOINTS CREEP TO AROUND 70 DEGREES.
THIS COULD MEAN A PROLONGED PERIOD WITH A HEAT ADVISORY...WITH MAX
HEAT INDICES NEARING 100 DEGREES AND OVERNIGHT LOW TEMPS REMAINING
ELEVATED IN THE LOW/MID 70S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1209 PM CDT THU AUG 22 2013

FEW CONCERNS DURING THE PERIOD AS HIGH PRESSURE OVER ND WORKS
SLOWLY SOUTHEASTWARD ACROSS MN/WI. BIGGEST PROBLEM IS THE WIND
DIRECTION THIS AFTERNOON. THE WIND WILL BE MAINLY FROM THE NE
(040-070) AT NEAR 10 KNOTS... BUT SOME EXCURIONS TO NORTH AND EAST
ARE POSSIBLE. GUSTS UP TO 20 KNOTS AS WELL THIS AFTERNOON.

KMSP...VFR THROUGH THE PD. MAIN CONCERN IS THE WIND DIRECTION AND
SPEED AS DESCRIBED ABOVE. RECENT AIRCRAFT DATA AT MSP INDICATED
NEAR 20 KNOT WINDS ABOUT 1200 FEET AGL. MIXING IS ALLOWING SOME OF
THIS TO REACH THE GROUND IN THE FORM OF GUSTS. LIGHT NE WIND THIS
EVENING BECOMING SE BY DAYBREAK AND THEN INCREASING TO AROUND 10
KNOTS BY LATE FRIDAY MORNING.

/OUTLOOK FOR KMSP/

FRI NGT...VFR. CHC SHRA/TSRA. WINDS SE 10 KTS.
SAT...VFR CHC SHRA/TSRA EARLY. WINDS SOUTH 18 KTS G 24 KTS.
SUN...VFR. SW WIND 15 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...RAH








AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 631 AM CDT THU AUG 22 2013

.UPDATE...
FOR 12Z AVIATION DISCUSSION BELOW

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT THU AUG 22 2013

SHORT TERM TRENDS POINT TO SOME ISOLATED THUNDER LIFTING AS FAR
NORTH AS DECAYING FRONTAL BOUNDARY...WITHIN INSTABILITY AXIS AND
NORTHERN PERIPHERY OF COMPLEX OVER IOWA. WILL HAVE TO INCLUDE THIS
FOR MUCH OF THE MORNING HOURS ANYWAY.

THIS CONVECTION IS BEING FORCED BY SOME WEAK LAYERED FRONTOGENESIS.
THIS IS PROGGED BE THE HRRR AND MEMBER 1 AND 2 OF THE HOPWRF TO
GRADUALLY WEAKEN AND DROP FARTHER SOUTH AS DRIER AIR TRIES TO DROP
SOUTHWEST ERODING THE BOUNDARY.  SHOULD SEE GRADUAL DRYING THEN INTO
THE AFTERNOON...AS SURFACE HIGH DROPS SOUTHEAST INTO TONIGHT.
CLOUDS SHOULD GIVE WAY TO CLEARING DURING THE DAY...AND CONTINUE
THIS TREND THROUGH THE NIGHT.  TEMPERATURES COOL A BIT TO THE LOWER
AND MIDDLE 80S OVER MOST OF THE AREA TODAY.  LOWS SHOULD COOL TO
AROUND 50 EAST AND AROUND 60 TO THE SOUTHWEST TONIGHT...AS DRIER AIR
MOVES ACROSS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 410 AM CDT THU AUG 22 2013

THE MAIN WEATHER HEADLINE IN THE LONG TERM PORTION OF THE FORECAST
WILL BE BUILDING HEAT...AS MID LEVEL HEIGHTS GRADUALLY RISE IN
CONJUNCTION WITH THE EXTENSIVE RIDGE OVER THE CENTRAL CONUS. THE RETURN
OF THE HOT WEATHER WILL BE MET WITH THE ARRIVAL OF A WARM FRONT.
HAVE RETAINED 20-40 POPS FOR FRIDAY NIGHT INTO SATURDAY MORNING AS
THE AFOREMENTIONED FRONT BEGINS TO LIFT ACROSS THE AREA. ALTHOUGH
THE ORIENTATION OF THE 35-40KT PROGGED LLJ IS NOT IDEAL FOR
WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...INDICATIONS ARE THAT
IT SHOULD BE ADEQUATE FROM CENTRAL MN INTO WEST CENTRAL WI TO
WARRANT LOW CHANCE POPS CENTERED BETWEEN 06Z AND 18Z SATURDAY.
AFTER THAT...OTHER THAN A FEW STRAY SHOWERS/TS NORTH OF INTERSTATE
94 CLOSER TO THE BOUNDARY...MOSTLY DRY CONDITIONS ARE EXPECTED
THROUGH MONDAY AS THE WARM FRONT LIFTS INTO NORTHERN MN. AS THIS
OCCURS...TEMPERATURES WILL MODERATE INTO THE LOW/MID 90S FOR
SUNDAY THROUGH TUESDAY AS DEWPOINTS CREEP TO AROUND 70 DEGREES.
THIS COULD MEAN A PROLONGED PERIOD WITH A HEAT ADVISORY...WITH MAX
HEAT INDICES NEARING 100 DEGREES AND OVERNIGHT LOW TEMPS REMAINING
ELEVATED IN THE LOW/MID 70S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 635 AM CDT THU AUG 22 2013

EXPECT THE SHRA/TS ACTIVITY TO STAY SOUTH OF THE TAF SITES
TODAY....WITH DRIER AIR WORKING IN FROM THE NORTH AS ILLUSTRATED
BY DEWPOINTS IN THE 40S ACROSS THE NORTHERN PORTION OF THE AREA
/CENTRAL MN/. FAIRLY EXTENSIVE CLOUD COVERAGE AT THE START OF THE
PERIOD SHOULD GIVE WAY TO CLEARING THIS AFTERNOON...WITH LIGHT
WINDS AS SURFACE HIGH PRESSURE SETTLES IN. NORTHEAST WINDS NEARING
10 MPH AT THE START OF THE PERIOD...DECREASING AND BECOMING LIGHT
AND VARIABLE BY 00Z.

KMSP...
CU AND CIRRUS BECOME LESS EXTENSIVE THROUGHOUT THE DAY...WITH
A MOSTLY CLEAR SKY EXPECTED BY 00Z. NORTHEAST WINDS 020-050 AROUND
9 KTS BECOME LIGHT AND VARIABLE BY 00Z.

/OUTLOOK FOR KMSP/
FRI...VFR. SCHC OF SHRA/TSRA LATE. SE WIND 5 TO 10 KTS.
SAT...OCNL MVFR-MAINLY VFR CIGS. CHANCE TSRA/SHRA. S WIND 12-18
KTS G 24 KTS.
SUN...VFR. SW WIND 12-18 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...LS







AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 410 AM CDT THU AUG 22 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT THU AUG 22 2013

SHORT TERM TRENDS POINT TO SOME ISOLATED THUNDER LIFTING AS FAR
NORTH AS DECAYING FRONTAL BOUNDARY...WITHIN INSTABILITY AXIS AND
NORTHERN PERIPHERY OF COMPLEX OVER IOWA. WILL HAVE TO INCLUDE THIS
FOR MUCH OF THE MORNING HOURS ANYWAY.

THIS CONVECTION IS BEING FORCED BY SOME WEAK LAYERED FRONTOGENESIS.
THIS IS PROGGED BE THE HRRR AND MEMBER 1 AND 2 OF THE HOPWRF TO
GRADUALLY WEAKEN AND DROP FARTHER SOUTH AS DRIER AIR TRIES TO DROP
SOUTHWEST ERODING THE BOUNDARY.  SHOULD SEE GRADUAL DRYING THEN INTO
THE AFTERNOON...AS SURFACE HIGH DROPS SOUTHEAST INTO TONIGHT.
CLOUDS SHOULD GIVE WAY TO CLEARING DURING THE DAY...AND CONTINUE
THIS TREND THROUGH THE NIGHT.  TEMPERATURES COOL A BIT TO THE LOWER
AND MIDDLE 80S OVER MOST OF THE AREA TODAY.  LOWS SHOULD COOL TO
AROUND 50 EAST AND AROUND 60 TO THE SOUTHWEST TONIGHT...AS DRIER AIR
MOVES ACROSS.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 410 AM CDT THU AUG 22 2013

THE MAIN WEATHER HEADLINE IN THE LONG TERM PORTION OF THE FORECAST
WILL BE BUILDING HEAT...AS MID LEVEL HEIGHTS GRADUALLY RISE IN
CONJUNCTION WITH THE EXTENSIVE RIDGE OVER THE CENTRAL CONUS. THE RETURN
OF THE HOT WEATHER WILL BE MET WITH THE ARRIVAL OF A WARM FRONT.
HAVE RETAINED 20-40 POPS FOR FRIDAY NIGHT INTO SATURDAY MORNING AS
THE AFOREMENTIONED FRONT BEGINS TO LIFT ACROSS THE AREA. ALTHOUGH
THE ORIENTATION OF THE 35-40KT PROGGED LLJ IS NOT IDEAL FOR
WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY...INDICATIONS ARE THAT
IT SHOULD BE ADEQUATE FROM CENTRAL MN INTO WEST CENTRAL WI TO
WARRANT LOW CHANCE POPS CENTERED BETWEEN 06Z AND 18Z SATURDAY.
AFTER THAT...OTHER THAN A FEW STRAY SHOWERS/TS NORTH OF INTERSTATE
94 CLOSER TO THE BOUNDARY...MOSTLY DRY CONDITIONS ARE EXPECTED
THROUGH MONDAY AS THE WARM FRONT LIFTS INTO NORTHERN MN. AS THIS
OCCURS...TEMPERATURES WILL MODERATE INTO THE LOW/MID 90S FOR
SUNDAY THROUGH TUESDAY AS DEWPOINTS CREEP TO AROUND 70 DEGREES.
THIS COULD MEAN A PROLONGED PERIOD WITH A HEAT ADVISORY...WITH MAX
HEAT INDICES NEARING 100 DEGREES AND OVERNIGHT LOW TEMPS REMAINING
ELEVATED IN THE LOW/MID 70S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1056 PM CDT WED AUG 21 2013

CDFNT GRADUALLY PROGRESSING SEWD THRU THE AREA...IDENTIFIABLE BY
WINDS SHIFTING TO PREDOMINANTLY NW ALTHOUGH SPEEDS ARE DROPPING TO
5 KT OR LESS. MOST SITES NOW LOOK TO REMAIN VFR THRU THIS PERIOD.
MAINLY HIGH CLOUDS EXPECTED AT KAXN-KSTC...WITH SOME ADDITIONAL
MIDLVL CLOUDS TMRW AFTN AT KMSP-KRNH. THE MAIN CONCERNS THIS
PERIOD ARE AT KEAU AND KRWF THRU DAYBREAK. FOR KEAU...FLIGHT CONDS
HAVE ALREADY DROPPED TO LIFR DUE TO LOW CIGS...BUT THE THREAT OF
IFR/LIFR CIGS CONDS REMAIN THRU DAYBREAK AS THAT AREA RECEIVED
PLENTY OF RAIN THIS EVE...RESULTING IN PLENTY OF LOW LEVEL
MOISTURE AVAILABLE FOR LOW CIGS /IF WINDS DO NOT GO CALM/ OR FOG
/IF WINDS GO CALM/. EITHER WAY...AM ANTICIPATING AT LEAST TEMPO
PERIODS OF IFR/LIFR THRU DAYBREAK THEN VFR AFTERWARDS. FOR
KRWF...THERE ARE COMPETING SHORT-RANGE MODEL IDEAS THAT
SHWRS/TSTMS OVER NE NEBRASKA MAY SLIDE ENE ALONG THE FNT AND MOVE
INTO SW MN. CHCS ON THIS IDEA ARE LOW...AND HOURLY MODEL
INITIALIZATIONS DO NOT LINE UP FAVORABLY...SO HAVE KEPT KRWF DRY
BUT DID ADD IN A MIDLVL CIG OVERNIGHT. ALL SITES THEN GO VFR TMRW
AFTN ONWARD WITH NE WINDS IN THE 5-10 KT RANGE BEFORE DROPPING OFF
TMRW EVE.

KMSP...VFR THROUGHOUT WITH NO PRECIP EXPECTED. MAINLY HIGH CLOUDS
WITH OCNL CIGS AT TIMES...AND SOME PASSING MIDLVL CU CLOUDS. NO
CIGS EXPECTED TMRW AFTN ON THRU THE REST OF THE PERIOD. NE WINDS
THROUGHOUT...APPROACHING 10 KT TMRW AFTN...THEN DROPPING TO
LGT/VRBL TMRW EVE.

/OUTLOOK FOR KMSP/
FRI...VFR. SCHC OF SHRA/TSRA. SE WIND 5 TO 10 KTS.
SAT...OCNL MVFR-MAINLY VFR CIGS. CHANCE TSRA/SHRA. S WIND 10-18 KTS.
SUN...VFR. SW WIND 10-18 KTS.


&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...DWE
LONG TERM...LS
AVIATION...JPC







AREA FORECAST DISCUSSION

NWS BUFFALO NY

 742 AM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT WILL SWEEP ACROSS THE REGION LATE TODAY...BRINGING A
ROUND OF SHOWERS AND THUNDERSTORMS. AFTER THIS...HIGH PRESSURE WILL
BUILD DOWN FROM THE UPPER LAKES AND BRING COOLER TEMPERATURES AND
FAIR WEATHER WHICH WILL LAST THROUGH THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AT 700 AM...THERE WAS AN UPPER LEVEL TROF ACROSS THE MID ATLANTIC
STATES AND BROKEN SHOWER AND THUNDERSTORM ACTIVITY AHEAD OF A COLD
FRONTAL BOUNDARY. MEANWHILE WESTERN NEW YORK SHOULD REMAIN BETWEEN
THESE TWO AREAS THIS MORNING WITH FAIR WEATHER AND HIGH CLOUD
FILTERED SUNSHINE. SOME PATCHY FOG DEVELOPED DURING THE EARLY
MORNING HOURS...BUT THIS SHOULD BURN OFF QUICKLY THROUGH MID-
MORNING. EARLY AFTERNOON HIGHS SHOULD BE FAIRLY SIMILAR TO
YESTERDAY...WITH HIGHS AGAIN IN THE LOWER TO MID 80S.

AFTER THIS...A UPPER LEVEL SHORTWAVE WILL TRACK ACROSS ONTARIO AND
THEN INTO QUEBEC THIS EVENING. THIS WILL PUSH A COLD FRONT ACROSS
OUR REGION LATE AFTERNOON. IN GENERAL...THE FRONTAL BOUNDARY
SHOULD PROVIDE ENOUGH OF A FOCUS TO BRING MEASURABLE PRECIPITATION
TO THE MAJORITY OF THE REGION. A MODEST SW FLOW OF 25 KTS AT 925
MB WILL INITIALLY PROVIDE SOME LAKE SHADOWING NE OF THE
LAKES...AND IT IS ALSO LIKELY TO DELAY THE FRONTAL PASSAGE A BIT.
HOWEVER...GIVEN FAIRLY WARM LAKE TEMPERATURES AND THE MODEST MID-
LEVEL FLOW...THE FRONTAL BOUNDARY WILL EVENTUALLY WIN OUT AND
BRING A ROUND OF SHOWERS AND THUNDERSTORMS TO MOST. THIS IS IDEA
IS GENERALLY SHOWN BY CONSENSUS OF THE 00Z RUNS OF THE NAM/RGEM/GFS
AND 03Z SREF ENSEMBLE GUIDANCE.

RECENT RUNS OF THE HRRR SUPPORT A SLIGHTLY SLOWER TIMING WITH THE
FRONT...AS IT INITIALLY STRUGGLES TO PUSH THROUGH THE SW FLOW UP
THE LAKES. NAM/GFS CAPES OF 1000 J/KG SHOULD BE ENOUGH INSTABILITY
FOR THE FRONT TO TAP INTO...WITH SHOWERS LIKELY TO DROP FROM NW TO
SE. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE IN THE
200 PM TO 800 PM TIMEFRAME.

SEVERE WEATHER POTENTIAL REMAINS LIMITED WITH 850 MB WINDS OF 25
KNOTS RESULTING IN WEAK TO MODEST SHEAR. HOWEVER...THE NORTH
COUNTRY IS CLOSEST TO THE SHORTWAVE AND WITH SEVERAL RUNS OF THE
HRRR DEVELOPING A LINE ACROSS QUEBEC WILL ADD A MENTION OF GUSTY
WINDS. OTHERWISE...LOCALIZED PULSE STORMS CANNOT BE RULED
OUT...BUT HAVE A LOW PROBABILITY OF OCCURRENCE AND ANY GIVEN
LOCATION. NAM/GFS FORECAST PWATS TO RISE TO 1.50 TO 1.75 INCHES
WHICH COULD POSE A THREAT FOR LOCALIZED HEAVY RAINS IF STORMS
STALL ALONG LAKE BREEZE BOUNDARIES. AT THIS TIME...HRRR RUNS AND
MOST MODEL GUIDANCE SUGGEST A BOUNDARY PROGRESSIVE ENOUGH TO KEEP
HEAVY RAINS FROM FOCUSING ON ANY ONE LOCATION.

THE FRONTAL BOUNDARY WILL PUSH SOUTH OF OUR REGION THIS
EVENING...WITH ANY LINGERING SHOWERS LIKELY TO DROP SOUTH AND EAST
OF THE REGION BY LATE EVENING. OTHERWISE...EXPECT CLEARING SKIES AND
NOTABLY COOLER TEMPERATURES. LOWS SHOULD DROP INTO THE UPPER 50S TO
AROUND 60.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
CANADIAN SOURCED HIGH PRESSURE WILL BUILD FROM THE GREAT LAKES ACROSS
NEW YORK FOR FRIDAY AND SATURDAY. THIS WILL BRING A RETURN TO MORE
COMFORTABLE TEMPERATURES WITH SUNNY AND DRY WEATHER. DESPITE THE
SUNSHINE...A LIGHT NORTHERLY FLOW AND 850MB TEMPERATURES RUNNING
AROUND +10C WILL KEEP DAYTIME HIGHS IN THE LOW TO MID 70S. THE DRY
AIR WITH CLEAR SKIES AND LIGHT WINDS AT NIGHT WILL BE IDEAL FOR
RADIATIONAL COOLING BRINGING COOLER OVERNIGHT TEMPERATURES THAN THE
WARMTH AND HUMIDITY WE HAVE SEEN OF RECENT NIGHTS. LOWS WILL FALL
INTO THE MID TO LOW 50S WITH SOME UPPER 40S WELL INLAND FROM THE
LAKES. LIMITED SURFACE MOISTURE MAY GET TRAPPED BELOW NOCTURNAL
INVERSIONS EACH NIGHT WITH PATCHY GROUND AND VALLEY FOG POSSIBLE
AWAY FROM URBAN LOCATIONS ACROSS LOW LYING AREAS AND NEAR SMALLER
LAKES AND STREAMS.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
BY SUNDAY SURFACE HIGH PRESSURE WILL BE DRIFTING OFF THE EASTERN
SEABOARD...ALLOWING A SOUTHWEST RETURN FLOW TO BEGIN MODERATING
TEMPERATURES. AFTER A COOL MORNING...EXPECT HIGHS TO GET TO WITHIN A
FEW DEGREES OF AVERAGE FOR LATE AUGUST. THERE WILL STILL BE A GOOD
AMOUNT OF SUNSHINE WITH NOTHING MORE THAN SOME HIGH CIRRUS DRIFTING
IN FROM AN UPSTREAM WARM FRONTAL BOUNDARY.

SUNDAY NIGHT THROUGH THE FIRST HALF OF NEXT WEEK THE PATTERN WILL
BECOME MORE ACTIVE. A STRONG RIDGE WILL REMAIN IN PLACE OVER THE
CENTRAL PLAINS AND EXPAND SLOWLY NORTH AND EAST TOWARDS THE REGION.
THE NORTHERN RING OF THE RIDGE WILL BECOME MORE ACTIVE WITH A PARADE
OF PACIFIC SHORTWAVES AND SOUTHWEST MONSOONAL CONVECTION DRIVEN
SHORTWAVES PROPAGATING ALONG THE US/CANADIAN BORDER. A WARM FRONT
WILL LIFT NORTHEAST ACROSS THE REGION LATE SUNDAY NIGHT AND
MONDAY...THEN THE BOUNDARY WILL STALL NEARBY FROM THE UPPER LAKES TO
NORTHERN NY. THE SHORTWAVES AND STALLED FRONTAL BOUNDARY WILL
PROVIDE A CORRIDOR TO FOCUS SEVERAL ROUNDS OF SHOWERS AND
CONVECTION...BUT TIMING AT THIS TIME RANGE WILL BE DIFFICULT. FOR
NOW HAVE FOLLOWED ECMWF TIMING CLOSELY WHICH ALLOWS A FORECAST CLOSE
TO PREVIOUS CONTINUITY...WITH CHANCE POPS SUNDAY NIGHT THROUGH
MONDAY NIGHT THEN AGAIN ON WEDNESDAY. THIS MAY NEED TO BE ADJUSTED
IN COMING DAYS WITH FURTHER MODEL TIMING ADJUSTMENTS EXPECTED.

AS LONG AS CONVECTION DOES NOT BECOME TOO WIDESPREAD OR LONG IN
DURATION...TEMPERATURES WILL CREEP ABOVE AVERAGE AGAIN NEXT WEEK AND
HUMIDITY WILL BE ON THE RISE.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
THROUGH THIS MORNING. EXPECT VFR CONDITIONS OUTSIDE OF SOME LIGHT
FOG WHICH SHOULD BURN OFF RATHER QUICKLY THROUGH MID-MORNING. A
FRONTAL BOUNDARY WILL DROP ACROSS THE REGION LATE THIS AFTERNOON.
THIS WILL LIKELY BRING SHOWERS TO MOST TAF LOCATIONS...WITH A
CHANCE OF THUNDERSTORMS. BRIEF PERIODS OF IFR OR LOWER CONDITIONS
ARE POSSIBLE IN THUNDERSTORMS DUE TO HEAVY RAIN. THE FRONT WILL
PUSH SOUTH OF THE REGION THIS EVENING...WITH A RETURN TO VFR
CONDITIONS. FOG MAY DEVELOP BEHIND THE FRONT...ESPECIALLY AT JHW.

OUTLOOK...
FRIDAY THROUGH SUNDAY...VFR.
MONDAY...MAINLY VFR WITH A CHANCE OF SHOWERS/THUNDERSTORMS.

&&

.MARINE...
WINDS WILL INCREASE TODAY...BUT SHOULD BE STRONGER ONSHORE THAN
THE WATERS DUE TO LAKE BREEZE ENHANCEMENT. EVEN STILL...EXPECT SW
WINDS TO BUILD WAVES UP TO 4 FEET ON LAKE ERIE...WHICH IS JUST SHY
OF SMALL CRAFT CRITERIA. THEN WINDS WILL SHIFT TO THE NW BEHIND
THE FRONT...AND GENERALLY RUN IN THE 10 TO 20 KNOT RANGE TONIGHT.
THIS WILL CAUSE WAVES TO INCREASE ON THE SOUTH SHORES OF LAKE
ONTARIO...WITH CONDITIONS AGAIN LIKELY TO APPROACH BUT NOT MEET
SMALL CRAFT ADVISORY CRITERIA.

AFTER THIS...HIGH PRESSURE WILL BUILD IN...WITH GENERALLY LIGHT
WINDS AND GOOD BOATING CONDITIONS EXPECTED FRIDAY THROUGH SUNDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

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





AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 311 PM EDT THU AUG 22 2013

.SYNOPSIS...
RIDGE OF HIGH PRESSURE OFFSHORE WILL SLOWLY GIVE WAY TO A COLD FRONT
APPROACHING FROM THE NORTHWEST ON FRIDAY. THIS FRONT WILL CROSS THE AREA
BY EARLY SATURDAY. THE COLD FRONT WILL USHER IN COOLER AND DRIER
CONDITIONS FOR THE WEEKEND INTO EARLY NEXT WEEK. A WARMING TREND WILL
TAKE PLACE MID WEEK NEXT WEEK AS HIGH PRESSURE SHIFTS OFFSHORE.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 3 PM THURSDAY...WATER VAPOR IMAGERY IS SHOWING THE SHORTWAVE
CONTINUING TO MOVE ACROSS THE MID-ATLANTIC AND EASTERN CAROLINAS.
LINES OF CONVECTION HAVE FORMED AND ARE MOVING TOWARD THE
EAST-SOUTHEAST. AT THIS TIME THE CONVECTION IS STAYING BELOW SEVERE
LIMITS AND IS MOVING AROUND 10 KNOTS. WITH THE LINEAR CONFIGURATION
THAT HAS DEVELOPED IT APPEARS THAT ANY THREAT FOR FLOODING IS SMALL.
THE
LATEST HRRR IS SHOWING THE CONVECTION CONTINUING TO THE COAST AND
DYING AS IT MOVES OUT OVER THE WATERS. EXPECT THE CONVECTION TO
CONTINUE THROUGH THE EARLY EVENING HOURS.

OVERNIGHT MINIMUM TEMPERATURES ARE EXPECTED TO FALL BACK INTO THE
LOWER 70S INLAND AND MID 70S AT THE BEACHES.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...CONCERN THROUGH THE SHORT TERM REVOLVES
AROUND A COLD FRONT WHICH WILL DROP THROUGH THE AREA LATE FRIDAY
NIGHT INTO SATURDAY...AND ITS RELATED CONVECTION POTENTIAL.

FRIDAY WILL BEGIN RATHER NICE...AND WILL BE A WARM DAY. SUBSIDENCE
BEHIND A DEPARTING SHORTWAVE WITH SUBTLE HEIGHT INCREASES ALOFT WILL
CREATE SUBSTANTIAL EARLY SUNSHINE. THIS WILL DRIVE TEMPS UP TO
AROUND 90 AWAY FROM THE BEACHES. THESE WARM TEMPS COMBINED LOW-LEVEL
SW FLOW AROUND RETREATING HIGH PRESSURE OFFSHORE WILL CREATE
SIGNIFICANT INSTABILITY...WITH SBCAPE AND MLCAPE APPROACHING 2000
J/KG FRIDAY AFTN. IN ADDITION...LOW-LEVEL LAPSE RATES FROM SURFACE
TO 850MB WILL BE QUITE STEEP...AND DCAPE REACHES 600-1000 J/KG
FRIDAY EVE. THESE ALL SUGGEST TSTM POTENTIAL. HOWEVER...BULK SHEAR
IS QUITE LOW...AND PWATS ARE ONLY ABOUT 1.8 INCHES...LIMITING SEVERE
POTENTIAL. SPC HAS PLACED THE AREA IN A "SEE TEXT" FOR THE SWODY2 AS
THE FRONT APPROACHES INTO THIS UNSTABLE ENVIRONMENT. HOWEVER...FEEL
SEVERE POTENTIAL IS QUITE LOW HERE SINCE THE FRONT WILL NOT CROSS
UNTIL VERY LATE FRIDAY NIGHT...AND SOUNDINGS ARE NOT SO SATURATED
THAT WET-MICROBURSTS ARE FAVORABLE. STILL...WITH THE STEEP LOW-LEVEL
LAPSE RATES AND HIGH INSTABILITY...AN ISOLATED STRONG WIND GUST
CANNOT BE RULED OUT IN ANY AFTN PULSE STORM OR NIGHTTIME CONVECTION
BEFORE THE SURFACE LAYER STABILIZES. THIS MEANS THE MOST LIKELY
PLACE FOR A STRONGER WIND GUST WOULD BE ALONG THE SEA BREEZE
CONVECTION...IF ANY...FRIDAY AFTN...OR ALONG THE FAR NORTHERN TIER
AS THE FRONT APPROACHES FRIDAY NIGHT. WILL NOT MENTION SEVERE IN
GRIDS OR ZONE FORECAST PRODUCT.

FROPA WILL OCCUR OVERNIGHT FRIDAY...AND BY SATURDAY MORNING WILL
HAVE CLEARED THE CWA. COOL HIGH PRESSURE BUILDS IN BEHIND THIS
FRONT...BUT AS NE WINDS DEVELOP...MOISTURE ADVECTION WILL COMMENCE
OFF THE OCEAN...AND IT WILL TAKE MUCH OF SATURDAY BEFORE DRYING OF
THE COLUMN BELOW 700MB OCCURS. THIS CREATES SHOWERS AND CLOUDS MOST
OF THE DAY...WITH CLEARING OCCURRING ONLY BY SATURDAY NIGHT FROM
NORTH TO SOUTH.

TEMPS FRIDAY NIGHT WILL BE TRICKY DUE TO TIMING OF THE FRONT...BUT
IT APPEARS NEGATIVE 850MB THERMAL ADVECTION HOLDS OFF UNTIL
SATURDAY...SO FRIDAY NIGHT TEMPS WILL BE ABOVE 70 CWA-WIDE. HIGHS
SATURDAY WILL REACH INTO THE LOW 80S...AND HAVE UNDERCUT MOS NUMBERS
A BIT. LOWS SATURDAY NIGHT WILL FALL WELL INTO THE 60S AS A MUCH
DRIER AIRMASS MOVES INTO THE REGION.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...MID LEVEL PATTERN WILL BE DOMINATED BY
MASSIVE RIDGING CENTER ACROSS KANSAS WITH AN EASTWARD
EXTENSION/AXIS ACROSS THE CAROLINAS. AT THE SURFACE...HIGH
PRESSURE AXIS WILL INITIALLY BE OVER THE MID ATLANTIC AND IN TIME
WILL BECOME ELONGATED EAST/WEST ACROSS THE SOUTHEAST. THE EASTERN
EDGE OF THE RIDGE WILL WEAKEN AS SEVERAL SHORTWAVES RIDE THE
PERIPHERY AND DIP SOUTHWARD. THERE WILL ALMOST CERTAINLY BE
SEVERAL MESOSCALE CONVECTIVE SYSTEMS WITH THIS PATTERN AND ONE IF
NOT MORE MAY BE A FACTOR LATE IN THE PERIOD BUT ALL BUT IMPOSSIBLE
TO PINPOINT THIS FAR OUT IN TIME. THUS...THE FORECAST REMAINS DRY
THROUGHOUT.

THE ONLY INTERESTING NOTE REGARDING TEMPERATURES IS THE MEX GUIDANCE
HAS DECREASED SOMEWHAT WITH 61 IN WILMINGTON FOR MONDAY MORNING.
THIS SEEMS LIKE A REASONABLE TREND...COOLER AS CLIMATOLOGY BECOMES
LESS OF A FACTOR WITH TIME AND GEFS 850MB TEMPERATURES ARE 2-3
STANDARD DEVIATIONS BELOW NORMAL.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...TERMINALS ARE CURRENTLY VFR AND VFR IS EXPECTED TO
CONTINUE THROUGH THE AFTERNOON AND EVENING OUTSIDE OF ANY
PRECIPITATION. AN UPPER IMPULSE IS PROGGED BY MODELS TO MOVE
ACROSS THE TERMINALS. SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED WITH HIGHEST CONFIDENCE OF VCTS/TEMPO MVFR CONDITIONS
ALONG THE SEA BREEZE AT KMYR/KCRE/KILM AND LOWEST CONFIDENCE AT
KFLO/KLBT. SHOWERS AND THUNDERSTORMS SHOULD END THIS EVENING WITH
LOSS OF HEATING. IN THE PRE-DAWN HOURS PATCHY FOG WILL DEVELOP
WITH THE HIGHEST CONFIDENCE OF SUB- VFR CONDITIONS AT KFLO/KLBT.
VFR SHOULD DEVELOP AN HOUR OR SO AFTER SUNRISE WITH VFR EXPECTED
THROUGH THE MORNING HOURS AT ALL TERMINALS.

EXTENDED OUTLOOK...SCATTERED SHOWERS AND T-STORMS FRIDAY AFTERNOON
THROUGH SATURDAY MORNING ASSOCIATED WITH A COLD FRONT. VFR SUNDAY
THROUGH TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM THURSDAY...HIGH PRESSURE CONTINUES TO RIDGE BACK
ACROSS THE COASTAL WATERS. THE WINDS WILL CONTINUE TO BE AT OR
LESS THAN 10 KNOTS FROM THE SOUTHWEST AND THIS WILL CONTINUE THE
BENIGN CONDITIONS WITH SEAS OF 2 TO 3 FEET. WITH A WEST-NORTHWEST
FLOW...WE MAY SEE A FEW THUNDERSTORMS TRYING TO WORK THEIR WAY
BACK OVER THE WATERS BUT THEY SHOULD ONLY BE AT OR NEAR THE
COASTLINE.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...PRE-FRONTAL AIRMASS FRIDAY WILL TRANSITION
TO POST-FRONTAL SATURDAY THANKS TO A COLD FRONT WHICH WILL DROP
SOUTHWARD ACROSS THE WATERS OVERNIGHT FRIDAY. SW WINDS WILL BE 10-15
KTS MOST OF FRIDAY...BEFORE RAPIDLY SHIFTING TO THE NORTH BY
SATURDAY MORNING AT LESS THAN 10 KTS...WITH A NE SURGE DEVELOPING AT
THE END OF THE PERIOD...INCREASING WINDS TO 15 KTS OR MORE. WAVES
WILL BE NEARLY ENTIRELY FORMED BY THE WIND-WAVE GROUP...WITH 2-3 FT
SEAS FRIDAY CREATED BY SW WIND CHOP...THEN BECOMING 2-4 FT LATE
SATURDAY THANKS TO THE DEVELOPING NE WIND WAVE.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...A FAIRLY BRISK NORTHEASTERLY FLOW WILL
PREVAIL FOR MOST OF THE DAY SUNDAY WITH SPEEDS 10-15 KNOTS AND
PROBABLY HOVERING MORE TOWARD THE HIGHER END OF THE RANGE. AS HIGH
PRESSURE WEAKENS AND MOVES TO THE SOUTH...WINDS WILL DIMINISH TO
TEN KNOTS OR LESS BY MONDAY AFTERNOON. A FURTHER SHIFTING OF THE
HIGH TO BASICALLY OVERHEAD WILL LEAD TO WINDS BASICALLY LIGHT AND
VARIABLE TUESDAY. OVERALL SEAS ARE NEVER REALLY IMPRESSIVE WITH
3-4 FEET SUNDAY TRENDING DOWN TO AROUND TWO FEET TUESDAY.

&&

.TIDES/COASTAL FLOODING...
AS OF 125 PM THURSDAY...THE LATEST TIDE FORECAST FOR THE CAPE FEAR
RIVER IN WILMINGTON IS SHOWING THE RIVER REACHING LEVELS OF MINOR
COASTAL FLOODING. THE PEAK OF THE TIDE IS FORECASTED TO REACH 5.5
FEET BETWEEN 11 PM AND MIDNIGHT. THUS A COASTAL FLOOD ADVISORY FOR THE
CAPE FEAR RIVER AROUND DOWNTOWN WILMINGTON HAS BEEN ISSUED BETWEEN
10 PM AND 1 AM.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 1 AM EDT
     FRIDAY FOR NCZ107.

MARINE...NONE.

&&

$$
SYNOPSIS...JDW
NEAR TERM...DRH
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...MRR/DRH
MARINE...JDW/SHK/DRH
TIDES/COASTAL FLOODING...DRH









AREA FORECAST DISCUSSION

NWS WILMINGTON NC

 147 PM EDT THU AUG 22 2013

.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL PERSIST OVER THE WESTERN ATLANTIC
OCEAN TODAY. A COLD FRONT WILL APPROACH FRIDAY AND WILL THEN
CROSS THE AREA EARLY SATURDAY USHERING IN COOLER AND DRIER
CONDITIONS FOR THE WEEKEND INTO EARLY NEXT WEEK. A WARMING TREND
WILL TAKE PLACE MID WEEK NEXT WEEK AS HIGH PRESSURE SHIFTS OFF
SHORE.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 145 PM THURSDAY...WATER VAPOR IMAGERY IS SHOWING THE
SHORTWAVE MOVING INTO THE EASTERN CAROLINAS. THE RADAR HAS BEGUN
DETECTING THE CONVECTION DEVELOPING OVER THE PEE DEE AREA AND
INLAND PORTIONS OF SOUTHEAST NORTH CAROLINA. WITH DENSE CLOUDS
ALONG THE COAST MOVING OFF THE COAST THE AFTERNOON HEATING WILL
COMMENCE IN THE AREA AND SCATTERED CONVECTION IS EXPECTED TO
DEVELOP AS DEPICTED IN THE 16 UTC RUN OF THE HRRR MESOSCALE MODEL.

AS THE SHORTWAVE IS FORECASTED TO MOVE OF THE COAST BETWEEN 21 AND
00 UTC EXPECT THE COVERAGE OF CONVECTION TO TREND BACK A BIT BY
THIS EVENING THEN FINALLY CEASE AFTER SUNSET.

OVERNIGHT MINIMUM TEMPERATURES ARE EXPECTED TO FALL BACK INTO THE
LOWER 70S INLAND AND MID 70S AT THE BEACHES.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...EXITING SHORTWAVE WILL PRODUCE SOME
SUBSIDENCE AND DRYING THROUGH THE MID LEVELS ON FRI. THE LOW TO
MID LEVEL FLOW BEHIND SHORTWAVE WILL HAVE A STRONG WESTERLY
COMPONENT. THEREFORE BEST CONVERGENCE WILL REMAIN CLOSER TO THE
COAST AS ON SHORE FLOW DEVELOPS IN SEA BREEZE. THIS WILL PRODUCE
BEST CHC OF SHWRS/TSTMS CLOSER TO THE COAST...ESPECIALLY FURTHER
SOUTH. THE DOWNSLOPE WESTERLY FLOW WILL ALSO HELP TO LIMIT OVERALL
ACTIVITY ON FRI. LOOKS LIKE A BREAK IN THE SOMEWHAT LIMITED
ACTIVITY WILL TAKE PLACE THROUGH THE EVENING BEFORE A COLD FRONT
ACTUALLY PUSHES SOUTHEAST INTO THE AREA. THE DEEPEST LAYER
MOISTURE LOOKS LIKE IT WILL BE OVERNIGHT FRI BUT THE POTENTIAL FOR
TSTMS DOES NOT LOOK TOO IMPRESSIVE AS THE FRONT COMES THROUGH AT
A NON-DIURNALLY FAVORED TIME OF DAY. THE H5 TROUGH WILL PUSH
FRONT SOUTH SAT MORNING...BUT LATEST GFS SHOWS INCREASED POTENTIAL
FOR SHWRS ON SAT WITH BEST CONVERGENCE FROM THE TIP OF CAPE FEAR
SOUTH...WHERE BEST CONVERGENCE AND RESIDUAL MOISTURE WILL BE.

DEEP N-NW FLOW DEVELOPING BEHIND FRONT AS MID TO UPPER TROUGH
AXIS SHIFTS FARTHER OFF THE COAST AND HIGH PRESSURE BUILDS IN
THROUGH SATURDAY. PCP WATER VALUES WILL DROP FROM CLOSE TO 2
INCHES AHEAD OF FRONT TO LESS THAN AN INCH BY END OF PERIOD OR
EARLY SUNDAY. THEREFORE EXPECT CLEARING THROUGH SAT NIGHT.
RESIDUAL LOW LEVEL MOISTURE FROM PCP MAY PRODUCE FOG ACROSS THE
AREA SAT NIGHT.

TEMPS WILL RUN SLIGHTLY ABOVE NORMAL IN A WARMER AIR MASS ON FRI
AIDED BY WESTERLY FLOW. CLOUDS AND SHOWERS ASSOCIATED WITH FRONT
WILL KEEP TEMPS ON THE HIGH SIDE FRI NIGHT BUT TEMPS WILL RUN
CLOSER TO NORMAL BY SAT INTO SAT NIGHT AS DRIER AIR MAKES ITS WAY
IN.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...DRIER AIR WILL CONTINUE TO MAKE ITS WAY
IN DEEPER NORTHERLY FLOW AS HIGH PRESSURE NOSES IN FROM THE NORTH
AS IT GRADUALLY SHIFTS EAST THROUGH MID WEEK. OVERALL EXPECT
PLENTY OF SUNSHINE WITH TEMPS MODERATING FROM BELOW NORMAL SUNDAY
INTO MONDAY TO ABOVE NORMAL BY WED AS MID TO UPPER RIDGE BUILDS
EAST INTO THE CAROLINAS PRODUCING H5 HEIGHT RISES. GRADIENT WINDS
WILL WEAKEN AS HIGH SHIFTS SOUTH AND EAST WITH MAINLY DIURNAL
SHIFTS DUE TO SEA BREEZE/LAND BREEZE. 850 TEMPS WILL BOTTOM OUT
AROUND 13C IN COOLER AIR ADVECTING IN BEHIND FRONT THROUGH SUNDAY
AND WILL RISE UP TO 18C BY TUES INTO WED. THE DIURNAL SWINGS IN
TEMPS WILL BE FAIRLY LARGE WITH DRY AIR IN PLACE AND DEWPOINT
TEMPS IN THE LOWER END OF 60S AND POSSIBLY BELOW OVER NORTHERN
TIER ZONES LATE SUNDAY INTO EARLY TUES.

&&

.AVIATION /18Z THURSDAY THROUGH MONDAY/...
AS OF 18Z...TERMINALS ARE CURRENTLY VFR AND VFR IS EXPECTED TO
CONTINUE THROUGH THE AFTERNOON AND EVENING OUTSIDE OF ANY
PRECIPITATION. AN UPPER IMPULSE IS PROGGED BY MODELS TO MOVE
ACROSS THE TERMINALS. SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED WITH HIGHEST CONFIDENCE OF VCTS/TEMPO MVFR CONDITIONS
ALONG THE SEA BREEZE AT KMYR/KCRE/KILM AND LOWEST CONFIDENCE AT
KFLO/KLBT. SHOWERS AND THUNDERSTORMS SHOULD END THIS EVENING WITH
LOSS OF HEATING. IN THE PRE-DAWN HOURS PATCHY FOG WILL DEVELOP
WITH THE HIGHEST CONFIDENCE OF SUB- VFR CONDITIONS AT KFLO/KLBT.
VFR SHOULD DEVELOP AN HOUR OR SO AFTER SUNRISE WITH VFR EXPECTED
THROUGH THE MORNING HOURS AT ALL TERMINALS.

EXTENDED OUTLOOK...SCATTERED SHOWERS AND T-STORMS FRIDAY AFTERNOON
THROUGH SATURDAY MORNING ASSOCIATED WITH A COLD FRONT. VFR SUNDAY
THROUGH TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 145 PM THURSDAY...HIGH PRESSURE CONTINUES TO RIDGE BACK
ACROSS THE COASTAL WATERS. THE WINDS WILL CONTINUE TO BE AT OR
LESS THAN 10 KNOTS FROM THE SOUTHWEST AND THIS WILL CONTINUE THE
BENIGN CONDITIONS WITH SEAS OF 2 TO 3 FEET. WITH A WEST-NORTHWEST
FLOW...WE MAY SEE A FEW THUNDERSTORMS TRYING TO WORK THEIR WAY
BACK OVER THE WATERS BUT THEY SHOULD ONLY BE AT OR NEAR THE
COASTLINE.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...WEST TO SOUTHWEST FLOW WILL VEER AROUND TO
THE NORTH TO NORTHEAST AND INCREASE SLIGHTLY AHEAD OF COLD FRONT
SLATED TO MOVE INTO AND THROUGH THE WATERS SATURDAY MORNING.
EXPECT WINDS 10-15 KTS THROUGH MUCH OF FRIDAY AHEAD OF FRONT. THE
WINDS WILL SHIFT AROUND TO THE NORTH TO NORTHEAST THROUGH SATURDAY
AND WILL CONTINUE TO VEER AROUND SLIGHTLY MORE AND WILL INCREASE
AS COOL AIR ADVECTS OVER WARMER WATERS PRODUCING A WELL MIXED
MARINE LAYER AND GUSTY NORTHEAST WINDS. WINDS MAY INCREASE UP TO A
SOLID 15 KTS OVERNIGHT SATURDAY AS CAA INCREASES. SEAS WILL INCREASE
SLIGHTLY UP AROUND 3 FT AHEAD OF COLD FRONT BUT BIGGER INCREASE UP
TO AROUND 4 FT WILL COME IN NORTHEAST SURGE BEHIND FRONT THROUGH
SATURDAY NIGHT INTO THE LATTER HALF OF THE WEEKEND.

LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...NORTHEAST WINDS UP TO 15 KTS MAY INCREASE
CLOSER TO 20 KTS IN OUTER WATERS AS COLD AIR ADVECTS OVER WATERS
AS HIGH PRESSURE BUILDS IN BEHIND COLD FRONT. THIS SURGE WILL
PRODUCE A RISE IN SEAS UP TO 4 FT AND MAYBE A LITTLE HIGHER IN THE
OUTER WATERS SUNDAY THROUGH SUNDAY NIGHT. THE WINDS WILL LIGHTEN
AS HIGH PRESSURE SHIFTS SOUTH AND AIR MASS BEGINS TO MODIFY
THROUGH LATE MONDAY. OVERALL SEAS WILL BE 2 TO 4 FT MOST WATERS.

&&

.TIDES/COASTAL FLOODING...
AS OF 125 PM THURSDAY...THE LATEST TIDE FORECAST FOR THE CAPE FEAR
RIVER IN WILMINGTON IS SHOWING THE RIVER REACHING LEVELS OF MINOR
COASTAL FLOODING. THE PEAK OF THE TIDE IS FORECASTED TO REACH 5.5
FEET BETWEEN 11 PM AND MIDNIGHT. THUS A COASTAL FLOOD ADVISORY FOR THE
CAPE FEAR RIVER AROUND DOWNTOWN WILMINGTON HAS BEEN ISSUED BETWEEN
10 PM AND 1 AM.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 1 AM EDT
     FRIDAY FOR NCZ107.

MARINE...NONE.

&&

$$
SYNOPSIS...
NEAR TERM...DRH
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...MRR
MARINE...
TIDES/COASTAL FLOODING...











AREA FORECAST DISCUSSION

NWS RALEIGH NC

 229 AM EDT THU AUG 22 2013

.SYNOPSIS...
A PRE-FRONTAL TROUGH WILL BE OVER THE REGION TODAY INTO EARLY
FRIDAY. A COLD FRONT WILL PUSH SOUTH THROUGH NORTH CAROLINA FRIDAY
NIGHT AND EARLY SATURDAY BRINGING COOLER AND DRIER AIR.

&&

.NEAR TERM /TONIGHT/...
AS OF 930 PM WEDNESDAY...

AFTER QUITE A WET LATE AFTERNOON THROUGH EARLY EVENING ESPECIALLY IN
THE SOUTHEAST CWA... THE REMAINDER OF THE NIGHT SHOULD TREND MUCH
DRIER FOR MOST OF CENTRAL NC. AN AREA OF STRATIFORM RAIN COVERS MUCH
OF THE COASTAL PLAIN... IN THE WAKE OF THE DISORGANIZED BAND OF
STORMS NOW MOVING INTO COASTAL NC. MOST CONVECTION-ALLOWING MODELS
AGREE ON NO SIGNIFICANT ADDITIONAL DEVELOPMENT OVERNIGHT... BUT ONE
EXCEPTION IS THE HRRR WHICH SUGGESTS THAT THE BAND OF CONVECTION NOW
EXTENDING FROM CENTRAL WV INTO SW VA/FAR NW NC (ASSOCIATED WITH DPVA
WITHIN THE MID LEVEL TROUGH) WILL PROGRESS EASTWARD OVER THE NEXT
SEVERAL HOURS... BRUSHING ACROSS THE NRN COUNTIES OF CENTRAL NC.
DEEP LAYER BULK SHEAR WILL REMAIN MARGINAL AT AROUND 25 KTS... BUT
THE RAP INDICATES ELEVATED INSTABILITY (MLCAPE OVER 1000 J/KG)
HOLDING THROUGH THE NIGHT. WITH ABOUT 30 METERS OF HEIGHT FALLS
ANTICIPATED OVERNIGHT IN NRN NC WITH THE TROUGH SHIFTING SLOWLY
EASTWARD JUST TO OUR NW... THIS MAY PROVIDE ENOUGH IMPETUS FOR THESE
STORMS TO HOLD TOGETHER AS THEY PUSH EASTWARD. ONCE THE
POST-CONVECTION RAIN CLEARS OUT OF THE EAST IN THE NEXT HOUR OR
SO... WILL RETAIN AN ISOLATED STORM MENTION OVERNIGHT EVERYWHERE
EXCEPT FOR SCATTERED COVERAGE ACROSS THE NORTH. TEMPS ARE ALREADY
VERY CLOSE TO THEIR ANTICIPATED OVERNIGHT LOWS... SO EXPECT READINGS
TO DIP JUST ANOTHER CATEGORY OR SO OVERNIGHT... RESULTING IN LOWS
69-73. -GIH

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 310 PM WEDNESDAY...

THURSDAY AND THURSDAY NIGHT:
MEAN FLOW WILL BECOME WESTERLY IN THE WAKE OF THE MID/UPPER TROUGH
EXITING THE AREA BETWEEN 12 TO 18Z...FINALLY DRYING OUT THE
THE ABNORMALLY MOIST(PWATS 1.75-2.00 INCHES)AIRMASS THAT HAS BEEN IN
PLACE OVER THE PAST SEVERAL DAYS. THIS DRYING ALONG WITH STRONG
SYNOPTIC SCALE SUBSIDENCE IN THE WAKE OF THE EXITING TROUGH WILL
LIKELY GO A LONG WAYS IN COUNTERACTING AFTERNOON HEATING AND
RESULTANT DESTABILIZATION TO KEEP CONVECTION AT A MINIMUM THURSDAY
AFTERNOON...ESPECIALLY WEST OF US 1. CONVECTIVE ALLOWING MODELS
STRONGLY SUPPORT THE ABOVE RATIONALE...AND AS SUCH HAVE OPTED TO
CUT POPS A BIT WITH SLIGHT/ISOLATED CHANCE IN THE WEST TO SMALL
CHANCE IN THE EAST. DRY THURSDAY NIGHT UNTIL THE ARRIVAL OF THE
COLD FRONT ON FRIDAY.

FULL SUN THICKNESSES WILL FINALLY BE REALIZED ALLOWING NEAR NORMAL
HIGHS IN THE UPPER 80S TO AROUND 90. LOWS THURSDAY NIGHT IN THE
UPPER 60S TO LOWER 70S.

FRIDAY:
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ON FRIDAY AS
A COLD FRONT MOVES THROUGH THE AREA AND MOISTURE REMAINS
SUFFICIENTLY HIGH (PWAT VALUES 1.75-2 INCHES). MODELS INDICATE
MODERATE INSTABILITY DEVELOPING DURING THE DAY ON FRIDAY...HOWEVER
GIVEN THAT THE STRONGER SHORT WAVE TROUGH WILL HAVE MOVED EAST OF
THE REGION BY FRIDAY MORNING...WEAK SHEAR (GENERALLY LESS THAN 20
KNOTS) IS PROGGED TO BE OVER THE REGION AND SHOULD THEREFORE LIMIT
ANY STORM ORGANIZATION. HIGHS WILL LIKELY BE IN THE MID/UPPER 80S TO
NEAR 90 DEGREES.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS OF 225 AM THURSDAY...

FRIDAY NIGHT AND SATURDAY:
THE SURFACE COLD FRONT MENTIONED ABOVE IN THE SHORT TERM IS EXPECTED
TO MOVE INTO THE AREA LATE FRIDAY EVENING INTO EARLY SATURDAY
MORNING AND BE NEAR THE NC/SC BORDER ACROSS THE CENTRAL PART OF THE
STATE... EXTENDING BACK EAST-NORTHEASTWARD INTO THE COASTAL PLAIN AT
AROUND 12Z SATURDAY. THE FRONTAL IS EXPECTED TO STALL BRIEFLY
THERE... UNTIL THE FINAL MID LEVEL S/W MOVES THROUGH THE AREA
SATURDAY AFTERNOON. THUS... WILL CONTINUE SOLID CHANCES FOR SHOWERS
AND STORMS ALONG AND AHEAD OF THE FRONT FRIDAY EVENING INTO EARLY
SATURDAY MORNING... ENDING FROM NORTH/NORTHWEST TO SOUTH/SOUTHEAST.
WILL CONTINUE TO ADVERTISE A SLIGHT CHANCE OF SHOWERS AND STORMS FOR
SATURDAY MORNING INTO THE AFTERNOON... UNTIL THE FINAL S/W TROUGH
MOVES THROUGH THE AREA THEN (HELPING TO PUSH THE FRONT FURTHER SOUTH
AND USHER IN DRIER AIR). LOWS SATURDAY MORNING WILL GREATLY DEPEND
ON THE TIMING OF THE FRONT AND RESULTANT ADVECTION OF DRIER AIR INTO
THE REGION. THUS... FOR NOW WILL GO WITH MID 60S NORTH TO LOWER 70S
SOUTH. HIGHS SATURDAY 83-86... WITH THE POSSIBILITY FOR HIGH TEMPS
EVEN A BIT LOWER THAN ADVERTISED.

SATURDAY NIGHT THROUGH WEDNESDAY:
SURFACE HIGH PRESSURE WILL BUILD INTO THE AREA AND SETTLE ACROSS THE
REGION FROM SATURDAY NIGHT THROUGH AT LEAST MONDAY. MEANWHILE A MID
LEVEL RIDGE CENTERED OVER THE CENTRAL PART OF THE COUNTRY WILL
EXTEND INTO OUR REGION FROM THE WEST. THIS WILL LEAD TO DRY
CONDITIONS WITH TEMPS SATURDAY NIGHT THROUGH MONDAY SLIGHTLY BELOW
NORMAL. MEDIUM RANGE MODELS ARE SHOWING THE NEXT POSSIBLE
DISTURBANCE AND CHANCE OF SHOWERS AND STORMS ROUNDING THE MID LEVEL
RIDGE AND MOVING ACROSS OUR AREA SOMETIME IN THE TUESDAY TO
WEDNESDAY NIGHT TIME FRAME. FOR NOW WILL BRING A SLIGHT CHANCE POP
INTO NORTHERN PORTIONS OF THE AREA FOR TUESDAY... WITH SLIGHT CHANCE
EVERYWHERE FOR WEDNESDAY. GIVEN THE TIME RANGE (DAY 6-7)... TIMING
OF SUCH DISTURBANCES REMAIN DIFFICULT IF THIS PART OF THE FORECAST.
AS SURFACE HIGH PRESSURE SLIPS TO THE SOUTH OF THE REGION... EXPECT
WE WILL SEE A WARM UP ON TUESDAY AND WEDNESDAY BACK TO SEASONAL
NORMS.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 200 AM THURSDAY...

IFR TO LIFR CIGS AND MVFR VSBYS EXPECTED ESPECIALLY AT
KINT/KGSO/KRWI THROUGH AROUND 12Z... THEN MVFR TO VFR CIGS AND VFR
VSBYS THIS AFTERNOON AND TONIGHT. THERE IS A CHANCE OF BRIEF MVFR TO
IFR CIGS/VSBYS WITH A THUNDERSTORM AT ALL SITES THIS AFTERNOON AND
EVENING.

LOOKING AHEAD:
A COLD FRONT WILL CROSS CENTRAL NC AND RESULT IN ANOTHER ROUND OF
SHOWERS AND STORMS...PARTICULARLY AT SOUTHERN AND EASTERN TERMINALS
WHERE THE TIMING OF THE FRONTAL PASSAGE WILL COINCIDE MORE CLOSELY
WITH PEAK DIURNAL HEATING/DESTABILIZATION. CALM TO LIGHT
NORTHEASTERLY LOW LEVEL FLOW IN MODIFIED CANADIAN SURFACE HIGH
PRESSURE MAY THEN RESULT IN VERY SHALLOW PRE-DAWN RADIATION FOG THIS
WEEKEND...MAINLY AT KRWI.

&&

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

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...HARTFIELD
SHORT TERM...CBL/KRR
LONG TERM...BSD
AVIATION...BADGETT














AREA FORECAST DISCUSSION

NWS RALEIGH NC

 200 AM EDT THU AUG 22 2013

.SYNOPSIS...
A PRE-FRONTAL TROUGH WILL BE OVER THE REGION TODAY INTO EARLY
FRIDAY. A COLD FRONT WILL PUSH SOUTH THROUGH NORTH CAROLINA FRIDAY
NIGHT AND EARLY SATURDAY BRINGING COOLER AND DRIER AIR.

&&

.NEAR TERM /TONIGHT/...
AS OF 930 PM WEDNESDAY...

AFTER QUITE A WET LATE AFTERNOON THROUGH EARLY EVENING ESPECIALLY IN
THE SOUTHEAST CWA... THE REMAINDER OF THE NIGHT SHOULD TREND MUCH
DRIER FOR MOST OF CENTRAL NC. AN AREA OF STRATIFORM RAIN COVERS MUCH
OF THE COASTAL PLAIN... IN THE WAKE OF THE DISORGANIZED BAND OF
STORMS NOW MOVING INTO COASTAL NC. MOST CONVECTION-ALLOWING MODELS
AGREE ON NO SIGNIFICANT ADDITIONAL DEVELOPMENT OVERNIGHT... BUT ONE
EXCEPTION IS THE HRRR WHICH SUGGESTS THAT THE BAND OF CONVECTION NOW
EXTENDING FROM CENTRAL WV INTO SW VA/FAR NW NC (ASSOCIATED WITH DPVA
WITHIN THE MID LEVEL TROUGH) WILL PROGRESS EASTWARD OVER THE NEXT
SEVERAL HOURS... BRUSHING ACROSS THE NRN COUNTIES OF CENTRAL NC.
DEEP LAYER BULK SHEAR WILL REMAIN MARGINAL AT AROUND 25 KTS... BUT
THE RAP INDICATES ELEVATED INSTABILITY (MLCAPE OVER 1000 J/KG)
HOLDING THROUGH THE NIGHT. WITH ABOUT 30 METERS OF HEIGHT FALLS
ANTICIPATED OVERNIGHT IN NRN NC WITH THE TROUGH SHIFTING SLOWLY
EASTWARD JUST TO OUR NW... THIS MAY PROVIDE ENOUGH IMPETUS FOR THESE
STORMS TO HOLD TOGETHER AS THEY PUSH EASTWARD. ONCE THE
POST-CONVECTION RAIN CLEARS OUT OF THE EAST IN THE NEXT HOUR OR
SO... WILL RETAIN AN ISOLATED STORM MENTION OVERNIGHT EVERYWHERE
EXCEPT FOR SCATTERED COVERAGE ACROSS THE NORTH. TEMPS ARE ALREADY
VERY CLOSE TO THEIR ANTICIPATED OVERNIGHT LOWS... SO EXPECT READINGS
TO DIP JUST ANOTHER CATEGORY OR SO OVERNIGHT... RESULTING IN LOWS
69-73. -GIH

&&

.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 310 PM WEDNESDAY...

MEAN FLOW WILL BECOME WESTERLY IN THE WAKE OF THE MID/UPPER TROUGH
EXITING THE AREA BETWEEN 12 TO 18Z...FINALLY DRYING OUT THE
THE ABNORMALLY MOIST(PWATS 1.75-2.00 INCHES)AIRMASS THAT HAS BEEN IN
PLACE OVER THE PAST SEVERAL DAYS. THIS DRYING ALONG WITH STRONG
SYNOPTIC SCALE SUBSIDENCE IN THE WAKE OF THE EXITING TROUGH WILL
LIKELY GO A LONG WAYS IN COUNTERACTING AFTERNOON HEATING AND
RESULTANT DESTABILIZATION TO KEEP CONVECTION AT A MINIMUM THURSDAY
AFTERNOON...ESPECIALLY WEST OF US 1. CONVECTIVE ALLOWING MODELS
STRONGLY SUPPORT THE ABOVE RATIONALE...AND AS SUCH HAVE OPTED TO
CUT POPS A BIT WITH SLIGHT/ISOLATED CHANCE IN THE WEST TO SMALL
CHANCE IN THE EAST. DRY THURSDAY NIGHT UNTIL THE ARRIVAL OF THE
COLD FRONT ON FRIDAY.

FULL SUN THICKNESSES WILL FINALLY BE REALIZED ALLOWING NEAR NORMAL
HIGHS IN THE UPPER 80S TO AROUND 90. LOWS THURSDAY NIGHT IN THE
UPPER 60S TO LOWER 70S.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 250 PM WEDNESDAY...

FRIDAY...SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE ON FRIDAY
AS A COLD FRONT MOVES THROUGH THE AREA AND MOISTURE REMAINS
SUFFICIENTLY HIGH (PWAT VALUES 1.75-2 INCHES). MODELS INDICATE
MODERATE INSTABILITY DEVELOPING DURING THE DAY ON FRIDAY...HOWEVER
GIVEN THAT THE STRONGER SHORT WAVE TROUGH WILL HAVE MOVED EAST OF
THE REGION BY FRIDAY MORNING...WEAK SHEAR (GENERALLY LESS THAN 20
KNOTS) IS PROGGED TO BE OVER THE REGION AND SHOULD THEREFORE LIMIT
ANY STORM ORGANIZATION. RAIN CHANCES SHOULD DIMINISH FROM NORTH TO
SOUTH FRIDAY NIGHT AS THE FRONT MOVES TOWARDS THE SC BORDER. HIGHS
WILL LIKELY BE IN THE MID/UPPER 80S TO NEAR 90 DEGREES WITH
OVERNIGHT LOWS GENERALLY IN THE MID/UPPER 60S TO NEAR 70 DEGREES
ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA.

SATURDAY THROUGH TUESDAY...LOWER DEEP LAYER MOISTURE WILL FILTER IN
BEHIND THE DEPARTING FRONT AS STRONG HIGH PRESSURE (ESPECIALLY FOR
AUGUST) BUILDS INTO THE AREA. THIS WILL RESULT IN A MOSTLY DRY
FORECAST...ALTHOUGH THERE COULD BE A COUPLE OF SHOWERS EARLY
SATURDAY MAINLY ACROSS THE SOUTH IN THE VICINITY OF THE SOUTHWARD
SINKING FRONT. DIURNAL TYPE RAIN CHANCES MAY BEGIN TO INCREASE BY
THE MIDDLE OF NEXT AS THE HIGH STARTS TO WEAKEN OVER THE AREA. TEMPS
WILL GENERALLY BE IN THE LOW/MID 80S...WITH A GRADUAL REBOUND BY
EARLY/MID NEXT WEEK.



&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 200 AM THURSDAY...

IFR TO LIFR CIGS AND MVFR VSBYS EXPECTED ESPECIALLY AT
KINT/KGSO/KRWI THROUGH AROUND 12Z... THEN MVFR TO VFR CIGS AND VFR
VSBYS THIS AFTERNOON AND TONIGHT. THERE IS A CHANCE OF BRIEF MVFR TO
IFR CIGS/VSBYS WITH A THUNDERSTORM AT ALL SITES THIS AFTERNOON AND
EVENING.

LOOKING AHEAD:
A COLD FRONT WILL CROSS CENTRAL NC AND RESULT IN ANOTHER ROUND OF
SHOWERS AND STORMS...PARTICULARLY AT SOUTHERN AND EASTERN TERMINALS
WHERE THE TIMING OF THE FRONTAL PASSAGE WILL COINCIDE MORE CLOSELY
WITH PEAK DIURNAL HEATING/DESTABILIZATION. CALM TO LIGHT
NORTHEASTERLY LOW LEVEL FLOW IN MODIFIED CANADIAN SURFACE HIGH
PRESSURE MAY THEN RESULT IN VERY SHALLOW PRE-DAWN RADIATION FOG THIS
WEEKEND...MAINLY AT KRWI.

&&

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

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...HARTFIELD
SHORT TERM...CBL
LONG TERM...KRR
AVIATION...BADGETT











AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 152 PM EDT THU AUG 22 2013

.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCE CROSSES TODAY. COLD FRONT
TONIGHT AND FRIDAY. HIGH PRESSURE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE. CONCERNS FOR MORE ORGANIZED CONVECTION THIS AFTERNOON
AND TONIGHT WITH PW.S AROUND 2 INCHES...HAS PROMPTED A FLASH FLOOD
WATCH FOR MUCH OF WEST VIRGINIA FROM 2 PM THIS AFTERNOON THRU 11 AM
FRIDAY. THE AREAS OF CONCERN ARE GENERALLY THOSE AREAS THAT RECEIVED
POCKETS OF HEAVY RAIN AND WATER ISSUES LAST EVENING. SEE BELOW FOR
AREA SPECIFICS.

PREVIOUS DISCUSSION BELOW...
UPR LOW SHOULD BE E OF AREA BY MORNING. WILL KEEP LOW POPS THRU
MORNING TO ACCOUNT FOR ANY POP UP SHRA WITH LIFT WITH UPR LVL SYS.
ATTENTION THEN TURNS UPSTREAM FOR POTENTIALLY ACTIVE AFTN ACROSS THE
AREA. MDLS HAVE BEEN FAIRLY CONSISTENT IN PAST 24 HRS ON BRINGING
DOWN A DISTURBANCE AND PREFRONTAL LINE OF CONVECTION LATER TDY. THIS
SHOWS UP NICELY IN THE H7-H5 LYR OMEGA FIELDS ALONG WITH MID LVL
PVA. THE QUESTION IS HOW MUCH INSTABILITY CAN BE REALIZED WITH
POTENTIAL FOR DEBRIS CLDS TO WORK IN HERE THIS MORNING. WILL HEDGE
THAT BULK OF DEBRIS CLDS WILL STAY W OF AREA...MORE INTO KY...AND
DISSIPATE AS RUC SUGGESTS. WILL LEAN ON FASTER NAM/WRF MDLS FOR
TIMING THIS AFTN...ALTHOUGH EVEN SLOWER GFS NOT TOO FAR BEHIND. WILL
BRING IN LKLY POPS INTO SE OH 17 TO 19Z AND LOWLANDS/NE KY 19 TO
21Z...INTO MTNS/SW VA 22 TO 00Z. THERE IS SOME CONCERN THIS TRIES TO
SLOW DOWN A BIT ACROSS S ZONES...IE SW VA...THIS EVE.
OVERALL...THOUGH...THIS SHOULD MOVE RIGHT ALONG WITH STORM MOTIONS
15 TO 20 KTS.

AS FOR WATER CONCERNS...THERE WERE SOME PLACES THAT
GOT A GOOD HIT YESTERDAY...MAINLY ALONG I64 CORRIDOR FROM HTS TO
CRW. PWATS SURGE RIGHT BACK UP NEAR 2 INCHES WITH THIS FEATURE
WHICH MEANS DOWNPOURS A GOOD BET. ELECTED TO CODE UP A HVY RA
MENTION IN WX GRIDS WITH CONVECTION. WITH DECENT STORM MOTIONS AND
MOVEMENT LESS CONDUCIVE TO TRAINING...WILL FORGO A WATCH ATTM BUT
PUT A MENTION IN HWO FOR POSSIBLE STREET FLOODING AND LOW LYING
AREA CONCERNS.

ASSUMING MDLS ARE CORRECT...SHOULD SEE A LULL THIS EVE BEFORE SFC
FRONT APPROACHES. MDLS SEEM TO PLACE FRONT ALONG OH RVR BY END OF
NEAR TERM. UNCLEAR ON HOW ACTIVE ACTUAL BOUNDARY WILL BE GIVEN
NIGHT TIME HRS. HOWEVER...WITH DECENT LIFT SHOWN...WILL CODE UP
SOME HIGH CHC POPS OVERNIGHT AND KEEP A SMALL THUNDER THREAT IN.

CANT RULE OUT A FEW SVR CELLS THIS AFTN...MAINLY WIND. BUT
AGAIN...DOWNPOURS BIGGEST ISSUE.

FOR TEMPS...HEDGED TOWARD LAMP GUIDANCE ONCE AGAIN GIVEN ITS
RECENT PERFORMANCE. THIS RESULTED IN MINOR TWEAKS HERE AND THERE
FROM PREV FCST. GENERALLY LOW TO MID 80S ONCE AGAIN. LEANED ON
WARM SIDE TONIGHT GIVEN ABUNDANCE OF MOISTURE ABOUT THE AREA AND
SHRA THREAT.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS STILL HAVE SOME TIMING DIFFERENCES ON FRIDAY WITH THE COLD
FRONT AND ASSOCIATED MOISTURE. NAM CONTINUES TO BE THE SLOWEST WHILE
THE CANADIAN IS THE FASTEST. GFS AND ECMWF LIE IN THE MIDDLE. WITH
NO OBVIOUS REASON WHY ONE MODEL WOULD BE BETTER THAN THE
OTHER...WILL CONTINUE TO RUN A MIDDLE OF THE ROAD SOLUTION.

HIGH PRESSURE THEN TAKES OVER FOR THE WEEKEND...PROVIDING DRY
WEATHER AND LOW HUMIDITY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS THROUGH THE LONG TERM
FORECAST. THE CENTER OF THE 500MB HIGH GENERALLY DRIFTS AROUND OVER
KS/OK/MO...WHICH KEEPS OUR REGION IN NW FLOW ALOFT...WITH SEVERAL
RIPPLES DROPPING THROUGH. TIMING/LOCATION OF EACH INDIVIDUAL WAVE
VARY BETWEEN GFS/ECMWF. SOME LOW LEVEL MOISTURE SHOULD BE AVAILABLE
WITH SE SURFACE FLOW...BUT JUST HOW MUCH WILL DEPEND ON WHERE
SURFACE HIGH IS. IF IT STAYS OVER THE SE STATES...WE WOULD GET AT
LEAST SOME MOISTURE ADVECTION FROM THE GULF...WHILE IF IT THE
SURFACE HIGH DRIFTS FARTHER WEST AS THE ECMWF HINTS...THAT RICHER
MOISTURE FLOW COULD GET CUT OF. DUE TO THIS UNCERTAINTY...STAYED
PRETTY CLOSE TO WPC GUIDANCE. WITH 500 HEIGHTS OVER 590DAM...LOOKS
LIKE A WARM STRETCH...WITH LOWLAND HIGHS IN THE UPPER 80S AND EVEN
SOME 90S NEXT WEEK. COULD ACTUALLY BE WARMER IF WE DO NOT HAVE THE
GOOD MOISTURE FLOW...AS THE DRIER AIR WOULD BE EASIER TO WARM.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z THURSDAY THRU 18Z FRIDAY...
CONVECTIVE COMPLEXES EXPECTED TO DROP SOUTHEAST ACROSS THE AREA THRU
06Z...WELL AHEAD OF THE COLD FRONT WHICH IS EXPECTED TO ENTER OUR
SOUTHEAST OHIO ZONES AROUND 09Z...THEN PROGRESS ACROSS THE AREA
DURING FRIDAY. MOST OF THE ACTION WILL BE AHEAD OF THE FRONT THIS
AFTERNOON AND EARLY TONIGHT...WITH ADDITIONAL LIGHTER CONVECTION
WITH THE FRONT ITSELF.

GENERALLY VFR SCT-BKN 3500-4000 FT AGL THRU 02Z OUTSIDE OF
CONVECTION. MVFR TO LOCALLY IFR IN STRONGER CONVECTION...ESPECIALLY
IN THE 22Z TO 03Z TIME PERIOD. THEREAFTER...EXPECT CONVECTION TO
DIMINISH IN COVERAGE AND INTENSITY...BUT REPLACED BY GENERAL MVFR
CEILINGS EXCEPT IFR IN THE HIGHER MOUNTAINS. DEPENDING ON CLOUD
COVER OVERNIGHT...FOG MAY BE AN ISSUE. EXPECT ENOUGH OF A BREAK FOR
IFR FOG CONDITIONS 06Z TO 12Z.

AFTER 12Z...LINGERING LIGHT SHOWERS ENDING AND CEILINGS IMPROVING TO
VFR FROM THE NORTHWEST BY END OF PERIOD.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...

FORECAST CONFIDENCE: LOW TO MEDIUM.

ALTERNATE SCENARIOS: TIMING OF CONVECTION THRU THE PERIOD DEPENDS
HIGHLY ON MESOSCALE COMPLEXES COMPLEXES. FOG WILL VARY DEPENDING ON
CLOUD COVER.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       18   19   20   21   22   23   00   01   02   03   04   05
EDT 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    L
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    M    H    H    H    H    H    H    H    H    H    M
EKN CONSISTENCY  M    H    H    H    H    H    H    H    H    L    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    M    M
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    M    M    M

AFTER 18Z FRIDAY...
AREAS OF IFR IN DENSE FOG/LOW STRATUS MOST MORNINGS THIS
WEEK...ESPECIALLY ALONG THE RIVERS. IFR IN SHOWERS AND THUNDERSTORMS
FRIDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR WVZ006>011-
     013>020-026>032-038>040-047.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/JMV/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...JMV











AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 1104 AM EDT THU AUG 22 2013

.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCE CROSSES TODAY. COLD FRONT
TONIGHT AND FRIDAY. HIGH PRESSURE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
11 AM UPDATE. CONCERNS FOR MORE ORGANIZED CONVECTION THIS AFTERNOON
AND TONIGHT WITH PW.S AROUND 2 INCHES...HAS PROMPTED A FLASH FLOOD
WATCH FOR MUCH OF WEST VIRGINIA FROM 2 PM THIS AFTERNOON THRU 11 AM
FRIDAY. THE AREAS OF CONCERN ARE GENERALLY THOSE AREAS THAT RECEIVED
POCKETS OF HEAVY RAIN AND WATER ISSUES LAST EVENING. SEE BELOW FOR
AREA SPECIFICS.

PREVIOUS DISCUSSION BELOW...
UPR LOW SHOULD BE E OF AREA BY MORNING. WILL KEEP LOW POPS THRU
MORNING TO ACCOUNT FOR ANY POP UP SHRA WITH LIFT WITH UPR LVL SYS.
ATTENTION THEN TURNS UPSTREAM FOR POTENTIALLY ACTIVE AFTN ACROSS THE
AREA. MDLS HAVE BEEN FAIRLY CONSISTENT IN PAST 24 HRS ON BRINGING
DOWN A DISTURBANCE AND PREFRONTAL LINE OF CONVECTION LATER TDY. THIS
SHOWS UP NICELY IN THE H7-H5 LYR OMEGA FIELDS ALONG WITH MID LVL
PVA. THE QUESTION IS HOW MUCH INSTABILITY CAN BE REALIZED WITH
POTENTIAL FOR DEBRIS CLDS TO WORK IN HERE THIS MORNING. WILL HEDGE
THAT BULK OF DEBRIS CLDS WILL STAY W OF AREA...MORE INTO KY...AND
DISSIPATE AS RUC SUGGESTS. WILL LEAN ON FASTER NAM/WRF MDLS FOR
TIMING THIS AFTN...ALTHOUGH EVEN SLOWER GFS NOT TOO FAR BEHIND. WILL
BRING IN LKLY POPS INTO SE OH 17 TO 19Z AND LOWLANDS/NE KY 19 TO
21Z...INTO MTNS/SW VA 22 TO 00Z. THERE IS SOME CONCERN THIS TRIES TO
SLOW DOWN A BIT ACROSS S ZONES...IE SW VA...THIS EVE.
OVERALL...THOUGH...THIS SHOULD MOVE RIGHT ALONG WITH STORM MOTIONS
15 TO 20 KTS.

AS FOR WATER CONCERNS...THERE WERE SOME PLACES THAT
GOT A GOOD HIT YESTERDAY...MAINLY ALONG I64 CORRIDOR FROM HTS TO
CRW. PWATS SURGE RIGHT BACK UP NEAR 2 INCHES WITH THIS FEATURE
WHICH MEANS DOWNPOURS A GOOD BET. ELECTED TO CODE UP A HVY RA
MENTION IN WX GRIDS WITH CONVECTION. WITH DECENT STORM MOTIONS AND
MOVEMENT LESS CONDUCIVE TO TRAINING...WILL FORGO A WATCH ATTM BUT
PUT A MENTION IN HWO FOR POSSIBLE STREET FLOODING AND LOW LYING
AREA CONCERNS.

ASSUMING MDLS ARE CORRECT...SHOULD SEE A LULL THIS EVE BEFORE SFC
FRONT APPROACHES. MDLS SEEM TO PLACE FRONT ALONG OH RVR BY END OF
NEAR TERM. UNCLEAR ON HOW ACTIVE ACTUAL BOUNDARY WILL BE GIVEN
NIGHT TIME HRS. HOWEVER...WITH DECENT LIFT SHOWN...WILL CODE UP
SOME HIGH CHC POPS OVERNIGHT AND KEEP A SMALL THUNDER THREAT IN.

CANT RULE OUT A FEW SVR CELLS THIS AFTN...MAINLY WIND. BUT
AGAIN...DOWNPOURS BIGGEST ISSUE.

FOR TEMPS...HEDGED TOWARD LAMP GUIDANCE ONCE AGAIN GIVEN ITS
RECENT PERFORMANCE. THIS RESULTED IN MINOR TWEAKS HERE AND THERE
FROM PREV FCST. GENERALLY LOW TO MID 80S ONCE AGAIN. LEANED ON
WARM SIDE TONIGHT GIVEN ABUNDANCE OF MOISTURE ABOUT THE AREA AND
SHRA THREAT.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS STILL HAVE SOME TIMING DIFFERENCES ON FRIDAY WITH THE COLD
FRONT AND ASSOCIATED MOISTURE. NAM CONTINUES TO BE THE SLOWEST WHILE
THE CANADIAN IS THE FASTEST. GFS AND ECMWF LIE IN THE MIDDLE. WITH
NO OBVIOUS REASON WHY ONE MODEL WOULD BE BETTER THAN THE
OTHER...WILL CONTINUE TO RUN A MIDDLE OF THE ROAD SOLUTION.

HIGH PRESSURE THEN TAKES OVER FOR THE WEEKEND...PROVIDING DRY
WEATHER AND LOW HUMIDITY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS THROUGH THE LONG TERM
FORECAST. THE CENTER OF THE 500MB HIGH GENERALLY DRIFTS AROUND OVER
KS/OK/MO...WHICH KEEPS OUR REGION IN NW FLOW ALOFT...WITH SEVERAL
RIPPLES DROPPING THROUGH. TIMING/LOCATION OF EACH INDIVIDUAL WAVE
VARY BETWEEN GFS/ECMWF. SOME LOW LEVEL MOISTURE SHOULD BE AVAILABLE
WITH SE SURFACE FLOW...BUT JUST HOW MUCH WILL DEPEND ON WHERE
SURFACE HIGH IS. IF IT STAYS OVER THE SE STATES...WE WOULD GET AT
LEAST SOME MOISTURE ADVECTION FROM THE GULF...WHILE IF IT THE
SURFACE HIGH DRIFTS FARTHER WEST AS THE ECMWF HINTS...THAT RICHER
MOISTURE FLOW COULD GET CUT OF. DUE TO THIS UNCERTAINTY...STAYED
PRETTY CLOSE TO WPC GUIDANCE. WITH 500 HEIGHTS OVER 590DAM...LOOKS
LIKE A WARM STRETCH...WITH LOWLAND HIGHS IN THE UPPER 80S AND EVEN
SOME 90S NEXT WEEK. COULD ACTUALLY BE WARMER IF WE DO NOT HAVE THE
GOOD MOISTURE FLOW...AS THE DRIER AIR WOULD BE EASIER TO WARM.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
15Z THURSDAY THRU 15Z FRIDAY...
MORNING IFR/MVFR STRATUS LIFTS TO VFR CEILINGS BY 17Z. EXPECT UPR
DISTURBANCE TO MAKE A RUN THRU AREA AFTER 18Z FROM NW...WELL AHEAD
OF SFC FRONT. AS SUCH...HAVE A PREDOMINATE SHRA/VCTS IN TAFS FOR
EXPECTED CONVECTIVE LINE IN AFTN WHICH WILL DROP SOUTHEAST. KEPT
PREDOMINATE VFR...BUT LOCALLY LOWER IN HEAVIER SHOWERS AND STORMS.

THINGS MAY QUIET DOWN AFTER 03Z TONIGHT UNTIL SFC FRONT APPROACHES
WITH PERHAPS ANOTHER ROUND OF SHRA LATER TONIGHT INTO FRIDAY
MORNING. NOT EXPECTING MUCH IN WAY OF DENSE FG TONIGHT WITH
ABUNDANCE OF CLDS ACROSS THE AREA.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF CONVECTION THIS AFTN MAY VARY A
FEW HRS.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       14   15   16   17   18   19   20   21   22   23   00   01
EDT 1HRLY       10   11   12   13   14   15   16   17   18   19   20   21
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 12Z FRIDAY...
AREAS OF IFR IN DENSE FOG/LOW STRATUS MOST MORNINGS THIS
WEEK...ESPECIALLY ALONG THE RIVERS. IFR IN SHOWERS AND THUNDERSTORMS
FRIDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR WVZ006>011-
     013>020-026>032-038>040-047.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/JMV/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...JMV/30











AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 721 AM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT OVER MICHIGAN WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING. HIGH PRESSURE THEN BUILDS BACK INTO THE
REGION FOR FRIDAY INTO THE WEEKEND. ANOTHER WEATHER SYSTEM WILL
AFFECT THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED TO TWEAKS THE POPS A LITTLE WITH AN AREA OF SHOWERS AND
POSSIBLE THUNDER DEVELOPING NORTH OF THE ISLANDS IN ONTARIO.
OTHERWISE THE FORECAST LOOKS GOOD...STILL SOME QUESTION HOW MUCH
ACTIVITY WILL OCCUR ALONG THE LAKE SHORE.

PREVIOUS DISCUSSION...
AN UPPER TROF IS MOVING OUT OF EXTREME EASTERN OHIO EARLY THIS
MORNING...IT IS TAKING THE CLOUDS WITH IT. A COLD FRONT WILL BE
MOVING THROUGH THE FORECAST AREA THIS AFTERNOON AND EVENING...THE
ISSUE/DILEMMA IS THE TIMING OF THUNDERSTORMS AND WILL THEY BE
SEVERE. AT 330 AM EDT THE AREA OF SHOWERS AND THUNDERSTORMS OVER
MICHIGAN WAS WEAKENING. MY PLAN BASED ON THE HRRR AND SOME OF THE
MODELS IS TO HAVE A CHANCE OF SHOWERS THIS AM OVER NORTHWEST OHIO
AND THEN A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY
INLAND THIS AFTERNOON AS THE FRONT MOVES IN AND WE GET SOME
HEATING. IT IS STILL NOT CLEAR IF ALL THE THUNDERSTORMS WILL
DEVELOP OVER NORTHERN OHIO AND NW PA OR WILL SOME THUNDERSTORMS
MOVE IN FROM MICHIGAN. AT THIS TIME GOING WITH NOT MUCH MOVING IN
FROM MICHIGAN SO KEEPING MOST OF THE ACTIVITY OVER THE INLAND
AREAS AND SCATTERED ALONG THE LAKE SHORE.

THE HIGHS ARE TOUGH TODAY IT ALL DEPENDS ON THE CLOUD COVER. I THINK
WE SHOULD HAVE SOME SUNSHINE. WENT CLOSE TO THE WARMER GUIDANCE.
ALSO THE CLOUD COVER WILL DETERMINE WHETHER SOME OF THE
THUNDERSTORMS COULD BE SEVERE. SINCE THE CLOUDS WITH THE COMPLEX
OVER MICHIGAN ARE DECREASING WE SHOULD GET SOME CAPE SO ISOLATED
SEVERE THUNDERSTORMS ARE POSSIBLE. THIS WILL BE MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
HIGH PRESSURE IS BUILDING TONIGHT AS THE COLD FRONT WILL BE ACROSS
THE INLAND AREAS BY 6 PM EDT. SOME SHOWERS AND THUNDERSTORMS WILL
LINGER EARLY IN THE EVENING BEFORE IT DRIES OUT. SOME OF THE MODELS
LIKE THE NAM AND THE CANADIAN MODEL TRY TO HANG THE COLD FRONT UP
OVER LAKE ERIE THIS EVENING. AT THIS TIME LEANING TOWARD THE GFS AND
ECMWF WHICH PUSHES THE FRONT THROUGH. THIS SEEMS REASONABLE BASED
ON WHAT IS GOING ON UPSTREAM AND THE STRENGTH OF THE HIGH.

A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY AND BE IN
CONTROL SATURDAY AND THEN SLIDE SOUTHEAST ON SUNDAY. AT THIS TIME A
DRY FORECAST WITH BELOW NORMAL TEMPERATURES FOR FRIDAY AND SATURDAY
AND THEN RECOVERING ON SUNDAY BACK TO NORMAL AS THE RIDGE WEAKENS
AND A SOUTHWEST FLOW DEVELOPS AGAIN. USED A BLEND OF GUIDANCE FOR
THE TEMPERATURES.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
BIG BUBBLE FINALLY PUSHES EAST IN THE UPPER LEVEL PATTERN. THE
PERSISTENT UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES WILL
COVER THE ENTIRE UNITED STATES AND BE CENTERED OVER THE MISSISSIPPI
RIVER VALLEY THROUGH MUCH OF THE EXTENDED FORECAST PERIOD.
ACTUALLY...THE LARGE UPPER LEVEL HIGH PRESSURE CENTER BUILDS OVER
THIS REGION DURING THE PERIOD HELPING TO STRENGTHEN THE CAUSE FOR
WARMER RETURN BACK TO SUMMER WEATHER.

THE ONLY FLY IN THE OINTMENT IS THE FACT THAT THE LOCAL AREA REMAINS
ON THE UPPER NORTHEAST PORTION OF THE RIDGE ALLOWING A FEW
SHORTWAVES TO DIVE DOWN ACROSS THE REGION AND BRING WITH IT A SUPPLY
OF MOISTURE AND THE THREAT FOR SHOWERS AND THUNDERSTORMS. MOISTURE
MAY BE LIMITED WITH THESE FEATURES AS THEY WILL NEED TO TRAVERSE
OVER A LARGE LAND MASS BEFORE ARRIVING HERE. SO WILL KEEP THE
MENTION OF SHOWERS AND THUNDERSTORMS JUST ABOUT EACH PERIOD.

AS MENTIONED ABOVE...FAIRLY STRONG WARM AIR ADVECTION WILL RETURN TO
THE FORECAST AREA DURING THE EXTENDED PERIODS. POTENTIAL EXISTS TO
SEE 90 DEGREES...ESPECIALLY IN THE WESTERN HALF OF THE FORECAST AREA
WHERE IT IS CLOSER TO THE UPPER LEVEL RIDGE. SOME SHOWER ACTIVITY IN
THE EAST MAY HELP KEEP TEMPERATURES OUT OF THE 90S.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
THE BIG QUESTION IS WHERE WILL THE SHOWERS AND THUNDERSTORMS
DEVELOP THIS MORNING. NEARLY ALL OF THE ACTIVITY THAT WAS OVER
MICHIGAN VIRTUALLY DIED OUT. NEW STUFF DEVELOPED AND IS NOW
WORKING ITS WAY SOUTHEAST ACROSS WESTERN LAKE ERIE. WILL THE
STABILITY OF THE LAKE REDUCE THE SHOWERS OR WILL THEY SURVIVE AS
THEY MOVE SOUTHEAST. LATEST ANALYSIS AND GUIDANCE SUGGESTS THE
POSSIBILITY OF MORE SHOWERS AND WEAK THUNDERSTORMS WILL DEVELOP
ALONG A NARROW BAND FROM WESTERN LAKE ERIE ACROSS NORTHWEST OHIO
THIS MORNING. THIS ACTIVITY WILL MOVE SOUTHEAST TODAY. SINCE THERE
IS SO MUCH UNCERTAINTY ON WHERE THE LINE WILL BE AND HOW NUMEROUS
THE SHOWERS WILL BE...WILL JUST MENTION VCSH OR VCTS. AFTER THINGS
SETTLE DOWN LATER TODAY...RETURN BACK TO VFR WITH EXCEPTION OF
SOME FOG IN THE WEST. WINDS SHIFT AROUND TO WEST NORTHWEST FOR THE
AFTERNOON AND OVERNIGHT HOURS.

OUTLOOK...NON-VFR IN FOG/MIST FRIDAY NIGHT. MVFR POSSIBLE MONDAY.

&&

.MARINE...
WINDS WILL BE ON THE INCREASE ACROSS THE LAKE TODAY AHEAD OF THE
COLD FRONT. FRONT LOOKS LIKE IT SHOULD SLIP SOUTH OF THE AREA BUT A
REINFORCING COLD FRONT STALLS JUST NORTH OF THE LAKE TODAY AND THEN
GRADUALLY SHIFTS SOUTH OF THE LAKE TONIGHT. MAY NEED A SMALL CRAFT
ADVISORY FOR A PERIOD LATE TONIGHT INTO FRIDAY...ESPECIALLY FROM
ABOUT CONNEAUT WEST. WINDS DIMINISH FAIRLY QUICKLY ON FRIDAY
ALLOWING WAVES TO SUBSIDE TO A FOOT OR LESS BY EVENING. A SLIGHT
INCREASE IN WAVES EXPECTED FRIDAY NIGHT WITH A LIGHT CHOP INTO EARLY
SATURDAY MORNING. THEN...LAKE SETTLES NICELY BY SUNDAY INTO SUNDAY
NIGHT WITH A SLIGHT INCREASE MONDAY WITH 1 TO 3 FOOTERS MAINLY NORTH
2/3RD`S OF THE LAKE.

&&

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

&&

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







AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 647 AM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT OVER MICHIGAN WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING. HIGH PRESSURE THEN BUILDS BACK INTO THE
REGION FOR FRIDAY INTO THE WEEKEND. ANOTHER WEATHER SYSTEM WILL
AFFECT THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED TO TWEAKS THE POPS A LITTLE WITH AN AREA OF SHOWERS AND
POSSIBLE THUNDER DEVELOPING NORTH OF THE ISLANDS IN ONTARIO.
OTHERWISE THE FORECAST LOOKS GOOD...STILL SOME QUESTION HOW MUCH
ACTIVITY WILL OCCUR ALONG THE LAKESHORE.

PREVIOUS DISCUSSION...
AN UPPER TROF IS MOVING OUT OF EXTREME EASTERN OHIO EARLY THIS
MORNING...IT IS TAKING THE CLOUDS WITH IT. A COLD FRONT WILL BE
MOVING THROUGH THE FORECAST AREA THIS AFTERNOON AND EVENING...THE
ISSUE/DILEMMA IS THE TIMING OF THUNDERSTORMS AND WILL THEY BE
SEVERE. AT 330 AM EDT THE AREA OF SHOWERS AND THUNDERSTORMS OVER
MICHIGAN WAS WEAKENING. MY PLAN BASED ON THE HRRR AND SOME OF THE
MODELS IS TO HAVE A CHANCE OF SHOWERS THIS AM OVER NORTHWEST OHIO
AND THEN A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY
INLAND THIS AFTERNOON AS THE FRONT MOVES IN AND WE GET SOME
HEATING. IT IS STILL NOT CLEAR IF ALL THE THUNDERSTORMS WILL
DEVELOP OVER NORTHERN OHIO AND NW PA OR WILL SOME THUNDERSTORMS
MOVE IN FROM MICHIGAN. AT THIS TIME GOING WITH NOT MUCH MOVING IN
FROM MICHIGAN SO KEEPING MOST OF THE ACTIVITY OVER THE INLAND
AREAS AND SCATTERED ALONG THE LAKESHORE.

THE HIGHS ARE TOUGH TODAY IT ALL DEPENDS ON THE CLOUD COVER. I THINK
WE SHOULD HAVE SOME SUNSHINE. WENT CLOSE TO THE WARMER GUIDANCE.
ALSO THE CLOUD COVER WILL DETERMINE WHETHER SOME OF THE
THUNDERSTORMS COULD BE SEVERE. SINCE THE CLOUDS WITH THE COMPLEX
OVER MICHIGAN ARE DECREASING WE SHOULD GET SOME CAPE SO ISOLATED
SEVERE THUNDERSTORMS ARE POSSIBLE. THIS WILL BE MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
HIGH PRESSURE IS BUILDING TONIGHT AS THE COLD FRONT WILL BE ACROSS
THE INLAND AREAS BY 6 PM EDT. SOME SHOWERS AND THUNDERSTORMS WILL
LINGER EARLY IN THE EVENING BEFORE IT DRIES OUT. SOME OF THE MODELS
LIKE THE NAM AND THE CANADIAN MODEL TRY TO HANG THE COLD FRONT UP
OVER LAKE ERIE THIS EVENING. AT THIS TIME LEANING TOWARD THE GFS AND
ECMWF WHICH PUSHES THE FRONT THROUGH. THIS SEEMS REASONABLE BASED
ON WHAT IS GOING ON UPSTREAM AND THE STRENGTH OF THE HIGH.

A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY AND BE IN
CONTROL SATURDAY AND THEN SLIDE SOUTHEAST ON SUNDAY. AT THIS TIME A
DRY FORECAST WITH BELOW NORMAL TEMPERATURES FOR FRIDAY AND SATURDAY
AND THEN RECOVERING ON SUNDAY BACK TO NORMAL AS THE RIDGE WEAKENS
AND A SOUTHWEST FLOW DEVELOPS AGAIN. USED A BLEND OF GUIDANCE FOR
THE TEMPERATURES.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
BIG BUBBLE FINALLY PUSHES EAST IN THE UPPER LEVEL PATTERN. THE
PERSISTENT UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES WILL
COVER THE ENTIRE UNITED STATES AND BE CENTERED OVER THE MISSISSIPPI
RIVER VALLEY THROUGH MUCH OF THE EXTENDED FORECAST PERIOD.
ACTUALLY...THE LARGE UPPER LEVEL HIGH PRESSURE CENTER BUILDS OVER
THIS REGION DURING THE PERIOD HELPING TO STRENGTHEN THE CAUSE FOR
WARMER RETURN BACK TO SUMMER WEATHER.

THE ONLY FLY IN THE OINTMENT IS THE FACT THAT THE LOCAL AREA REMAINS
ON THE UPPER NORTHEAST PORTION OF THE RIDGE ALLOWING A FEW
SHORTWAVES TO DIVE DOWN ACROSS THE REGION AND BRING WITH IT A SUPPLY
OF MOISTURE AND THE THREAT FOR SHOWERS AND THUNDERSTORMS. MOISTURE
MAY BE LIMITED WITH THESE FEATURES AS THEY WILL NEED TO TRAVERSE
OVER A LARGE LAND MASS BEFORE ARRIVING HERE. SO WILL KEEP THE
MENTION OF SHOWERS AND THUNDERSTORMS JUST ABOUT EACH PERIOD.

AS MENTIONED ABOVE...FAIRLY STRONG WARM AIR ADVECTION WILL RETURN TO
THE FORECAST AREA DURING THE EXTENDED PERIODS. POTENTIAL EXISTS TO
SEE 90 DEGREES...ESPECIALLY IN THE WESTERN HALF OF THE FORECAST AREA
WHERE IT IS CLOSER TO THE UPPER LEVEL RIDGE. SOME SHOWER ACTIVITY IN
THE EAST MAY HELP KEEP TEMPERATURES OUT OF THE 90S.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A LINE OF CONVECTION CONTINUES TO MOVE SOUTHEAST OUT OF SOUTHERN
LOWER MICHIGAN. THIS ACTIVITY IS JUST AHEAD OF THE COLD FRONT AT
THIS TIME. THE ACTIVITY SHOULD MOVE SOUTHEAST TOWARD TOLEDO AND
FINDLAY BY 12Z THIS MORNING AND THEN SPREAD EAST ACROSS THE REST
OF THE AREA THROUGHOUT THE MORNING. THE OTHER PROBLEM WILL BE FOG
DEVELOPMENT ACROSS THE AREA. WINDS SHOULD HELP KEEP DENSE FOG FROM
DEVELOPING ALL LOCATIONS BUT THERE IS A POSSIBILITY FOR
VISIBILITIES TO DROP TO AROUND 2 MILES AT AKRON CANTON AND
YOUNGSTOWN. CONVECTION MOVES SOUTH AND EAST OF THE AREA THIS
AFTERNOON. THE HOPE IS THAT FRONT DOES NOT STALL OVER THE AREA AND
KEEP A THREAT GOING FOR SHOWERS AND THUNDERSTORMS INTO THE EVENING.

OUTLOOK...NON-VFR IN FOG/MIST LATE TONIGHT AND FRIDAY NIGHT. MVFR
POSSIBLE MONDAY.

&&

.MARINE...
WINDS WILL BE ON THE INCREASE ACROSS THE LAKE TODAY AHEAD OF THE
COLD FRONT. FRONT LOOKS LIKE IT SHOULD SLIP SOUTH OF THE AREA BUT A
REINFORCING COLD FRONT STALLS JUST NORTH OF THE LAKE TODAY AND THEN
GRADUALLY SHIFTS SOUTH OF THE LAKE TONIGHT. MAY NEED A SMALL CRAFT
ADVISORY FOR A PERIOD LATE TONIGHT INTO FRIDAY...ESPECIALLY FROM
ABOUT CONNEAUT WEST. WINDS DIMINISH FAIRLY QUICKLY ON FRIDAY
ALLOWING WAVES TO SUBSIDE TO A FOOT OR LESS BY EVENING. A SLIGHT
INCREASE IN WAVES EXPECTED FRIDAY NIGHT WITH A LIGHT CHOP INTO EARLY
SATURDAY MORNING. THEN...LAKE SETTLES NICELY BY SUNDAY INTO SUNDAY
NIGHT WITH A SLIGHT INCREASE MONDAY WITH 1 TO 3 FOOTERS MAINLY NORTH
2/3RD`S OF THE LAKE.

&&

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

&&

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







AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 633 AM EDT THU AUG 22 2013

.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCE CROSSES TODAY. COLD FRONT
TONIGHT AND FRIDAY. HIGH PRESSURE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...

NO SIGNIFICANT CHANGES THIS MORNING.

PREVIOUS DISCUSSION BELOW...

UPR LOW SHOULD BE E OF AREA BY MORNING. WILL KEEP LOW POPS THRU
MORNING TO ACCOUNT FOR ANY POP UP SHRA WITH LIFT WITH UPR LVL SYS.
ATTENTION THEN TURNS UPSTREAM FOR POTENTIALLY ACTIVE AFTN ACROSS
THE AREA. MDLS HAVE BEEN FAIRLY CONSISTENT IN PAST 24 HRS ON
BRINGING DOWN A DISTURBANCE AND PREFRONTAL LINE OF CONVECTION
LATER TDY. THIS SHOWS UP NICELY IN THE H7-H5 LYR OMEGA FIELDS
ALONG WITH MID LVL PVA. THE QUESTION IS HOW MUCH INSTABILITY CAN
BE REALIZED WITH POTENTIAL FOR DEBRIS CLDS TO WORK IN HERE THIS
MORNING. WILL HEDGE THAT BULK OF DEBRIS CLDS WILL STAY W OF
AREA...MORE INTO KY...AND DISSIPATE AS RUC SUGGESTS. WILL LEAN ON
FASTER NAM/WRF MDLS FOR TIMING THIS AFTN...ALTHOUGH EVEN SLOWER
GFS NOT TOO FAR BEHIND. WILL BRING IN LKLY POPS INTO SE OH 17 TO
19Z AND LOWLANDS/NE KY 19 TO 21Z...INTO MTNS/SW VA 22 TO 00Z.
THERE IS SOME CONCERN THIS TRIES TO SLOW DOWN A BIT ACROSS S
ZONES...IE SW VA...THIS EVE. OVERALL...THOUGH...THIS SHOULD MOVE
RIGHT ALONG WITH STORM MOTIONS 15 TO 20 KTS.

AS FOR WATER CONCERNS...THERE WERE SOME PLACES THAT
GOT A GOOD HIT YESTERDAY...MAINLY ALONG I64 CORRIDOR FROM HTS TO
CRW. PWATS SURGE RIGHT BACK UP NEAR 2 INCHES WITH THIS FEATURE
WHICH MEANS DOWNPOURS A GOOD BET. ELECTED TO CODE UP A HVY RA
MENTION IN WX GRIDS WITH CONVECTION. WITH DECENT STORM MOTIONS AND
MOVEMENT LESS CONDUCIVE TO TRAINING...WILL FORGO A WATCH ATTM BUT
PUT A MENTION IN HWO FOR POSSIBLE STREET FLOODING AND LOW LYING
AREA CONCERNS.

ASSUMING MDLS ARE CORRECT...SHOULD SEE A LULL THIS EVE BEFORE SFC
FRONT APPROACHES. MDLS SEEM TO PLACE FRONT ALONG OH RVR BY END OF
NEAR TERM. UNCLEAR ON HOW ACTIVE ACTUAL BOUNDARY WILL BE GIVEN
NIGHT TIME HRS. HOWEVER...WITH DECENT LIFT SHOWN...WILL CODE UP
SOME HIGH CHC POPS OVERNIGHT AND KEEP A SMALL THUNDER THREAT IN.

CANT RULE OUT A FEW SVR CELLS THIS AFTN...MAINLY WIND. BUT
AGAIN...DOWNPOURS BIGGEST ISSUE.

FOR TEMPS...HEDGED TOWARD LAMP GUIDANCE ONCE AGAIN GIVEN ITS
RECENT PERFORMANCE. THIS RESULTED IN MINOR TWEAKS HERE AND THERE
FROM PREV FCST. GENERALLY LOW TO MID 80S ONCE AGAIN. LEANED ON
WARM SIDE TONIGHT GIVEN ABUNDANCE OF MOISTURE ABOUT THE AREA AND
SHRA THREAT.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS STILL HAVE SOME TIMING DIFFERENCES ON FRIDAY WITH THE COLD
FRONT AND ASSOCIATED MOISTURE. NAM CONTINUES TO BE THE SLOWEST WHILE
THE CANADIAN IS THE FASTEST. GFS AND ECMWF LIE IN THE MIDDLE. WITH
NO OBVIOUS REASON WHY ONE MODEL WOULD BE BETTER THAN THE
OTHER...WILL CONTINUE TO RUN A MIDDLE OF THE ROAD SOLUTION.

HIGH PRESSURE THEN TAKES OVER FOR THE WEEKEND...PROVIDING DRY
WEATHER AND LOW HUMIDITY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS THROUGH THE LONG TERM
FORECAST. THE CENTER OF THE 500MB HIGH GENERALLY DRIFTS AROUND OVER
KS/OK/MO...WHICH KEEPS OUR REGION IN NW FLOW ALOFT...WITH SEVERAL
RIPPLES DROPPING THROUGH. TIMING/LOCATION OF EACH INDIVIDUAL WAVE
VARY BETWEEN GFS/ECMWF. SOME LOW LEVEL MOISTURE SHOULD BE AVAILABLE
WITH SE SURFACE FLOW...BUT JUST HOW MUCH WILL DEPEND ON WHERE
SURFACE HIGH IS. IF IT STAYS OVER THE SE STATES...WE WOULD GET AT
LEAST SOME MOISTURE ADVECTION FROM THE GULF...WHILE IF IT THE
SURFACE HIGH DRIFTS FARTHER WEST AS THE ECMWF HINTS...THAT RICHER
MOISTURE FLOW COULD GET CUT OF. DUE TO THIS UNCERTAINTY...STAYED
PRETTY CLOSE TO WPC GUIDANCE. WITH 500 HEIGHTS OVER 590DAM...LOOKS
LIKE A WARM STRETCH...WITH LOWLAND HIGHS IN THE UPPER 80S AND EVEN
SOME 90S NEXT WEEK. COULD ACTUALLY BE WARMER IF WE DO NOT HAVE THE
GOOD MOISTURE FLOW...AS THE DRIER AIR WOULD BE EASIER TO WARM.

&&

.AVIATION /10Z THURSDAY THROUGH MONDAY/...
12Z THURSDAY THRU 12Z FRIDAY...

UPR S/W TROF PUSHES E OF AREA AFTER 13Z. ISOLD SHRA THREAT THRU
MORNING...BUT CHC NOT GREAT ENOUGH TO INCLUDE IN TAFS.

FG LIFTS AFTER 12Z FOR A RETURN TO VFR CONDITIONS. ANY MORNING
STRATUS SHOULD SCT OUT BY 14Z. HAVE SOME CU FORMING BY LATE
MORNING WITH AREA IN BETWEEN WX SYS. EXPECT UPR DISTURBANCE TO
MAKE A RUN THRU AREA AFTER 18Z FROM NW...WELL AHEAD OF SFC FRONT.
AS SUCH...HAVE A PREDOMINATE SHRA/VCTS IN TAFS FOR EXPECTED
CONVECTIVE LINE IN AFTN. KEPT PREDOMINATE VFR THOUGH GIVEN AT THIS
RANGE.

THINGS MAY QUIET DOWN AFTER 03Z TONIGHT UNTIL SFC FRONT APPROACHES
WITH PERHAPS ANOTHER ROUND OF SHRA. NOT EXPECTING MUCH IN WAY OF
DENSE FG TONIGHT WITH ABUNDANCE OF CLDS ACROSS THE AREA.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: TIMING OF CONVECTION THIS AFTN MAY VARY A
FEW HRS.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

UTC 1HRLY       11   12   13   14   15   16   17   18   19   20   21   22
EDT 1HRLY       07   08   09   10   11   12   13   14   15   16   17   18
CRW CONSISTENCY  L    M    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  L    L    L    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  L    M    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  L    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  M    H    H    H    H    H    H    H    H    H    H    H

AFTER 12Z FRIDAY...
AREAS OF IFR IN DENSE FOG/LOW STRATUS MOST MORNINGS THIS
WEEK...ESPECIALLY ALONG THE RIVERS. IFR IN SHOWERS AND THUNDERSTORMS
FRIDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...30









AREA FORECAST DISCUSSION

NWS CLEVELAND OH

 359 AM EDT THU AUG 22 2013

.SYNOPSIS...
A COLD FRONT OVER MICHIGAN WILL MOVE ACROSS THE AREA THIS
AFTERNOON AND EVENING. HIGH PRESSURE THEN BUILDS BACK INTO THE
REGION FOR FRIDAY INTO THE WEEKEND. ANOTHER WEATHER SYSTEM WILL
AFFECT THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPPER TROF IS MOVING OUT OF EXTREME EASTERN OHIO EARLY THIS
MORNING...IT IS TAKING THE CLOUDS WITH IT. A COLD FRONT WILL BE
MOVING THROUGH THE FORECAST AREA THIS AFTERNOON AND EVENING...THE
ISSUE/DILEMMA IS THE TIMING OF THUNDERSTORMS AND WILL THEY BE
SEVERE. AT 330 AM EDT THE AREA OF SHOWERS AND THUNDERSTORMS OVER
MICHIGAN WAS WEAKENING. MY PLAN BASED ON THE HRRR AND SOME OF THE
MODELS IS TO HAVE A CHANCE OF SHOWERS THIS AM OVER NORTHWEST OHIO
AND THEN A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY
INLAND THIS AFTERNOON AS THE FRONT MOVES IN AND WE GET SOME
HEATING. IT IS STILL NOT CLEAR IF ALL THE THUNDERSTORMS WILL
DEVELOP OVER NORTHERN OHIO AND NW PA OR WILL SOME THUNDERSTORMS
MOVE IN FROM MICHIGAN. AT THIS TIME GOING WITH NOT MUCH MOVING IN
FROM MICHIGAN SO KEEPING MOST OF THE ACTIVITY OVER THE INLAND
AREAS AND SCATTERED ALONG THE LAKESHORE.

THE HIGHS ARE TOUGH TODAY IT ALL DEPENDS ON THE CLOUD COVER. I THINK
WE SHOULD HAVE SOME SUNSHINE. WENT CLOSE TO THE WARMER GUIDANCE.
ALSO THE CLOUD COVER WILL DETERMINE WHETHER SOME OF THE
THUNDERSTORMS COULD BE SEVERE. SINCE THE CLOUDS WITH THE COMPLEX
OVER MICHIGAN ARE DECREASING WE SHOULD GET SOME CAPE SO ISOLATED
SEVERE THUNDERSTORMS ARE POSSIBLE. THIS WILL BE MENTIONED IN THE
HAZARDOUS WEATHER OUTLOOK.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
HIGH PRESSURE IS BUILDING TONIGHT AS THE COLD FRONT WILL BE ACROSS
THE INLAND AREAS BY 6 PM EDT. SOME SHOWERS AND THUNDERSTORMS WILL
LINGER EARLY IN THE EVENING BEFORE IT DRIES OUT. SOME OF THE MODELS
LIKE THE NAM AND THE CANADIAN MODEL TRY TO HANG THE COLD FRONT UP
OVER LAKE ERIE THIS EVENING. AT THIS TIME LEANING TOWARD THE GFS AND
ECMWF WHICH PUSHES THE FRONT THROUGH. THIS SEEMS REASONABLE BASED
ON WHAT IS GOING ON UPSTREAM AND THE STRENGTH OF THE HIGH.

A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY AND BE IN
CONTROL SATURDAY AND THEN SLIDE SOUTHEAST ON SUNDAY. AT THIS TIME A
DRY FORECAST WITH BELOW NORMAL TEMPERATURES FOR FRIDAY AND SATURDAY
AND THEN RECOVERING ON SUNDAY BACK TO NORMAL AS THE RIDGE WEAKENS
AND A SOUTHWEST FLOW DEVELOPS AGAIN. USED A BLEND OF GUIDANCE FOR
THE TEMPERATURES.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
BIG BUBBLE FINALLY PUSHES EAST IN THE UPPER LEVEL PATTERN. THE
PERSISTENT UPPER LEVEL RIDGE OVER THE WESTERN UNITED STATES WILL
COVER THE ENTIRE UNITED STATES AND BE CENTERED OVER THE MISSISSIPPI
RIVER VALLEY THROUGH MUCH OF THE EXTENDED FORECAST PERIOD.
ACTUALLY...THE LARGE UPPER LEVEL HIGH PRESSURE CENTER BUILDS OVER
THIS REGION DURING THE PERIOD HELPING TO STRENGTHEN THE CAUSE FOR
WARMER RETURN BACK TO SUMMER WEATHER.

THE ONLY FLY IN THE OINTMENT IS THE FACT THAT THE LOCAL AREA REMAINS
ON THE UPPER NORTHEAST PORTION OF THE RIDGE ALLOWING A FEW
SHORTWAVES TO DIVE DOWN ACROSS THE REGION AND BRING WITH IT A SUPPLY
OF MOISTURE AND THE THREAT FOR SHOWERS AND THUNDERSTORMS. MOISTURE
MAY BE LIMITED WITH THESE FEATURES AS THEY WILL NEED TO TRAVERSE
OVER A LARGE LAND MASS BEFORE ARRIVING HERE. SO WILL KEEP THE
MENTION OF SHOWERS AND THUNDERSTORMS JUST ABOUT EACH PERIOD.

AS MENTIONED ABOVE...FAIRLY STRONG WARM AIR ADVECTION WILL RETURN TO
THE FORECAST AREA DURING THE EXTENDED PERIODS. POTENTIAL EXISTS TO
SEE 90 DEGREES...ESPECIALLY IN THE WESTERN HALF OF THE FORECAST AREA
WHERE IT IS CLOSER TO THE UPPER LEVEL RIDGE. SOME SHOWER ACTIVITY IN
THE EAST MAY HELP KEEP TEMPERATURES OUT OF THE 90S.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A LINE OF CONVECTION CONTINUES TO MOVE SOUTHEAST OUT OF SOUTHERN
LOWER MICHIGAN. THIS ACTIVITY IS JUST AHEAD OF THE COLD FRONT AT
THIS TIME. THE ACTIVITY SHOULD MOVE SOUTHEAST TOWARD TOLEDO AND
FINDLAY BY 12Z THIS MORNING AND THEN SPREAD EAST ACROSS THE REST
OF THE AREA THROUGHOUT THE MORNING. THE OTHER PROBLEM WILL BE FOG
DEVELOPMENT ACROSS THE AREA. WINDS SHOULD HELP KEEP DENSE FOG FROM
DEVELOPING ALL LOCATIONS BUT THERE IS A POSSIBILITY FOR
VISIBILITIES TO DROP TO AROUND 2 MILES AT AKRON CANTON AND
YOUNGSTOWN. CONVECTION MOVES SOUTH AND EAST OF THE AREA THIS
AFTERNOON. THE HOPE IS THAT FRONT DOES NOT STALL OVER THE AREA AND
KEEP A THREAT GOING FOR SHOWERS AND THUNDERSTORMS INTO THE EVENING.

OUTLOOK...NON-VFR IN FOG/MIST LATE TONIGHT AND FRIDAY NIGHT. MVFR
POSSIBLE MONDAY.

&&

.MARINE...
WINDS WILL BE ON THE INCREASE ACROSS THE LAKE TODAY AHEAD OF THE
COLD FRONT. FRONT LOOKS LIKE IT SHOULD SLIP SOUTH OF THE AREA BUT A
REINFORCING COLD FRONT STALLS JUST NORTH OF THE LAKE TODAY AND THEN
GRADUALLY SHIFTS SOUTH OF THE LAKE TONIGHT. MAY NEED A SMALL CRAFT
ADVISORY FOR A PERIOD LATE TONIGHT INTO FRIDAY...ESPECIALLY FROM
ABOUT CONNEAUT WEST. WINDS DIMINISH FAIRLY QUICKLY ON FRIDAY
ALLOWING WAVES TO SUBSIDE TO A FOOT OR LESS BY EVENING. A SLIGHT
INCREASE IN WAVES EXPECTED FRIDAY NIGHT WITH A LIGHT CHOP INTO EARLY
SATURDAY MORNING. THEN...LAKE SETTLES NICELY BY SUNDAY INTO SUNDAY
NIGHT WITH A SLIGHT INCREASE MONDAY WITH 1 TO 3 FOOTERS MAINLY NORTH
2/3RD`S OF THE LAKE.

&&

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

&&

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







AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 250 AM EDT THU AUG 22 2013

.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCE CROSSES TODAY. COLD FRONT
TONIGHT AND FRIDAY. HIGH PRESSURE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPR LOW SHOULD BE E OF AREA BY MORNING. WILL KEEP LOW POPS THRU
MORNING TO ACCOUNT FOR ANY POP UP SHRA WITH LIFT WITH UPR LVL SYS.
ATTENTION THEN TURNS UPSTREAM FOR POTENTIALLY ACTIVE AFTN ACROSS
THE AREA. MDLS HAVE BEEN FAIRLY CONSISTENT IN PAST 24 HRS ON
BRINGING DOWN A DISTURBANCE AND PREFRONTAL LINE OF CONVECTION
LATER TDY. THIS SHOWS UP NICELY IN THE H7-H5 LYR OMEGA FIELDS
ALONG WITH MID LVL PVA. THE QUESTION IS HOW MUCH INSTABILITY CAN
BE REALIZED WITH POTENTIAL FOR DEBRIS CLDS TO WORK IN HERE THIS
MORNING. WILL HEDGE THAT BULK OF DEBRIS CLDS WILL STAY W OF
AREA...MORE INTO KY...AND DISSIPATE AS RUC SUGGESTS. WILL LEAN ON
FASTER NAM/WRF MDLS FOR TIMING THIS AFTN...ALTHOUGH EVEN SLOWER
GFS NOT TOO FAR BEHIND. WILL BRING IN LKLY POPS INTO SE OH 17 TO
19Z AND LOWLANDS/NE KY 19 TO 21Z...INTO MTNS/SW VA 22 TO 00Z.
THERE IS SOME CONCERN THIS TRIES TO SLOW DOWN A BIT ACROSS S
ZONES...IE SW VA...THIS EVE. OVERALL...THOUGH...THIS SHOULD MOVE
RIGHT ALONG WITH STORM MOTIONS 15 TO 20 KTS.

AS FOR WATER CONCERNS...THERE WERE SOME PLACES THAT
GOT A GOOD HIT YESTERDAY...MAINLY ALONG I64 CORRIDOR FROM HTS TO
CRW. PWATS SURGE RIGHT BACK UP NEAR 2 INCHES WITH THIS FEATURE
WHICH MEANS DOWNPOURS A GOOD BET. ELECTED TO CODE UP A HVY RA
MENTION IN WX GRIDS WITH CONVECTION. WITH DECENT STORM MOTIONS AND
MOVEMENT LESS CONDUCIVE TO TRAINING...WILL FORGO A WATCH ATTM BUT
PUT A MENTION IN HWO FOR POSSIBLE STREET FLOODING AND LOW LYING
AREA CONCERNS.

ASSUMING MDLS ARE CORRECT...SHOULD SEE A LULL THIS EVE BEFORE SFC
FRONT APPROACHES. MDLS SEEM TO PLACE FRONT ALONG OH RVR BY END OF
NEAR TERM. UNCLEAR ON HOW ACTIVE ACTUAL BOUNDARY WILL BE GIVEN
NIGHT TIME HRS. HOWEVER...WITH DECENT LIFT SHOWN...WILL CODE UP
SOME HIGH CHC POPS OVERNIGHT AND KEEP A SMALL THUNDER THREAT IN.

CANT RULE OUT A FEW SVR CELLS THIS AFTN...MAINLY WIND. BUT
AGAIN...DOWNPOURS BIGGEST ISSUE.

FOR TEMPS...HEDGED TOWARD LAMP GUIDANCE ONCE AGAIN GIVEN ITS
RECENT PERFORMANCE. THIS RESULTED IN MINOR TWEAKS HERE AND THERE
FROM PREV FCST. GENERALLY LOW TO MID 80S ONCE AGAIN. LEANED ON
WARM SIDE TONIGHT GIVEN ABUNDANCE OF MOISTURE ABOUT THE AREA AND
SHRA THREAT.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
MODELS STILL HAVE SOME TIMING DIFFERENCES ON FRIDAY WITH THE COLD
FRONT AND ASSOCIATED MOISTURE. NAM CONTINUES TO BE THE SLOWEST WHILE
THE CANADIAN IS THE FASTEST. GFS AND ECMWF LIE IN THE MIDDLE. WITH
NO OBVIOUS REASON WHY ONE MODEL WOULD BE BETTER THAN THE
OTHER...WILL CONTINUE TO RUN A MIDDLE OF THE ROAD SOLUTION.

HIGH PRESSURE THEN TAKES OVER FOR THE WEEKEND...PROVIDING DRY
WEATHER AND LOW HUMIDITY.


&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS THROUGH THE LONG TERM
FORECAST. THE CENTER OF THE 500MB HIGH GENERALLY DRIFTS AROUND OVER
KS/OK/MO...WHICH KEEPS OUR REGION IN NW FLOW ALOFT...WITH SEVERAL
RIPPLES DROPPING THROUGH. TIMING/LOCATION OF EACH INDIVIDUAL WAVE
VARY BETWEEN GFS/ECMWF. SOME LOW LEVEL MOISTURE SHOULD BE AVAILABLE
WITH SE SURFACE FLOW...BUT JUST HOW MUCH WILL DEPEND ON WHERE
SURFACE HIGH IS. IF IT STAYS OVER THE SE STATES...WE WOULD GET AT
LEAST SOME MOISTURE ADVECTION FROM THE GULF...WHILE IF IT THE
SURFACE HIGH DRIFTS FARTHER WEST AS THE ECMWF HINTS...THAT RICHER
MOISTURE FLOW COULD GET CUT OF. DUE TO THIS UNCERTAINTY...STAYED
PRETTY CLOSE TO WPC GUIDANCE. WITH 500 HEIGHTS OVER 590DAM...LOOKS
LIKE A WARM STRETCH...WITH LOWLAND HIGHS IN THE UPPER 80S AND EVEN
SOME 90S NEXT WEEK. COULD ACTUALLY BE WARMER IF WE DO NOT HAVE THE
GOOD MOISTURE FLOW...AS THE DRIER AIR WOULD BE EASIER TO WARM.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY...

UPR S/W TROF PUSHES E OF AREA AFTER 12Z. ISOLD SHRA THREAT THRU
MORNING...BUT CHC NOT GREAT ENOUGH TO INCLUDE IN TAFS. DIFFICULT FG
FCST THRU MORNING WITH VARIOUS AREAS OF HI CLDS...MAINLY ACROSS
THE N. ALSO A SLIGHT PUFF AT SFC TO COMPLICATE FG FORMATION
DESPITE RAINS YESTERDAY. PLAYED UP FG INITIALLY KCRW/KBKW BEFORE
TRYING TO LIFT OUT BY 09Z WITH EXPECTATION THAT HI CLDS MOVE IN
AND A SLIGHT SFC WIND BECOMES REALIZED. ELSEWHERE...ONLY HAVE MVFR
FG IN. THERE IS A CONCERN FOR SOME LOW STRATUS ACROSS KCKB AND
KEKN THRU MORNING BUT ELECTED TO LEAVE OUT OF TAFS ATTM AND FOLLOW
TRENDS FOR ANY AMENDMENTS.

FG LIFTS AFTER 12Z FOR A RETURN TO VFR CONDITIONS. HAVE SOME CU
FORMING BY MID MORNING WITH AREA IN BETWEEN WX SYS. EXPECT UPR
DISTURBANCE TO MAKE A RUN THRU AREA AFTER 18Z FROM NW...WELL AHEAD
OF SFC FRONT. AS SUCH...HAVE A PREDOMINATE SHRA/VCTS IN TAFS FOR
EXPECTED CONVECTIVE LINE IN AFTN. KEPT PREDOMINATE VFR THOUGH
GIVEN AT THIS RANGE.

THINGS MAY QUIET DOWN AFTER 00Z TONIGHT UNTIL SFC FRONT APPROACHES
WITH PERHAPS ANOTHER ROUND OF SHRA. NOT EXPECTING MUCH IN WAY OF
DENSE FG TONIGHT WITH ABUNDANCE OF CLDS ACROSS THE AREA.

SHOWERS AND THUNDERSTORMS WILL FIRE BACK UP AGAIN AFTER 16-18Z
THURSDAY AS A COLD FRONT APPROACHES FROM THE NORTH. EXPECT BRIEF
MVFR/IFR CONDITIONS IN VICINITY OF STORMS.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: FOG MAY HOLD FOR CRW/BKW LONGER THAN
EXPECTED. MVFR STRATUS MAY DEVELOP FOR KCKB/KEKN THRU 12Z. TIMING
OF CONVECTION THIS AFTN MAY VARY A FEW HRS.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE                              THU 08/22/13
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  M    M    L    L    L    L    H    M    H    H    H    H
HTS CONSISTENCY  M    M    L    L    L    H    H    M    H    H    H    H
BKW CONSISTENCY  L    H    H    H    H    L    L    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    L    L    L    H    H    H    H    H
PKB CONSISTENCY  H    H    L    L    L    L    H    H    H    H    H    H
CKB CONSISTENCY  L    L    L    L    L    H    H    H    H    H    H    H

AFTER 06Z FRIDAY...
AREAS OF IFR IN DENSE FOG/LOW STRATUS MOST MORNINGS THIS
WEEK...ESPECIALLY ALONG THE RIVERS. IFR IN SHOWERS AND THUNDERSTORMS
FRIDAY.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...MZ
AVIATION...30











AREA FORECAST DISCUSSION

NWS CHARLESTON WV

 248 AM EDT THU AUG 22 2013

.SYNOPSIS...
MID/UPPER LEVEL DISTURBANCE CROSSES TODAY. COLD FRONT
TONIGHT AND FRIDAY. HIGH PRESSURE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPR LOW SHOULD BE E OF AREA BY MORNING. WILL KEEP LOW POPS THRU
MORNING TO ACCOUNT FOR ANY POP UP SHRA WITH LIFT WITH UPR LVL SYS.
ATTENTION THEN TURNS UPSTREAM FOR POTENTIALLY ACTIVE AFTN ACROSS
THE AREA. MDLS HAVE BEEN FAIRLY CONSISTENT IN PAST 24 HRS ON
BRINGING DOWN A DISTURBANCE AND PREFRONTAL LINE OF CONVECTION
LATER TDY. THIS SHOWS UP NICELY IN THE H7-H5 LYR OMEGA FIELDS
ALONG WITH MID LVL PVA. THE QUESTION IS HOW MUCH INSTABILITY CAN
BE REALIZED WITH POTENTIAL FOR DEBRIS CLDS TO WORK IN HERE THIS
MORNING. WILL HEDGE THAT BULK OF DEBRIS CLDS WILL STAY W OF
AREA...MORE INTO KY...AND DISSIPATE AS RUC SUGGESTS. WILL LEAN ON
FASTER NAM/WRF MDLS FOR TIMING THIS AFTN...ALTHOUGH EVEN SLOWER
GFS NOT TOO FAR BEHIND. WILL BRING IN LKLY POPS INTO SE OH 17 TO
19Z AND LOWLANDS/NE KY 19 TO 21Z...INTO MTNS/SW VA 22 TO 00Z.
THERE IS SOME CONCERN THIS TRIES TO SLOW DOWN A BIT ACROSS S
ZONES...IE SW VA...THIS EVE. OVERALL...THOUGH...THIS SHOULD MOVE
RIGHT ALONG WITH STORM MOTIONS 15 TO 20 KTS.

AS FOR WATER CONCERNS...THERE WERE SOME PLACES THAT
GOT A GOOD HIT YESTERDAY...MAINLY ALONG I64 CORRIDOR FROM HTS TO
CRW. PWATS SURGE RIGHT BACK UP NEAR 2 INCHES WITH THIS FEATURE
WHICH MEANS DOWNPOURS A GOOD BET. ELECTED TO CODE UP A HVY RA
MENTION IN WX GRIDS WITH CONVECTION. WITH DECENT STORM MOTIONS AND
MOVEMENT LESS CONDUCIVE TO TRAINING...WILL FORGO A WATCH ATTM BUT
PUT A MENTION IN HWO FOR POSSIBLE STREET FLOODING AND LOW LYING
AREA CONCERNS.

ASSUMING MDLS ARE CORRECT...SHOULD SEE A LULL THIS EVE BEFORE SFC
FRONT APPROACHES. MDLS SEEM TO PLACE FRONT ALONG OH RVR BY END OF
NEAR TERM. UNCLEAR ON HOW ACTIVE ACTUAL BOUNDARY WILL BE GIVEN
NIGHT TIME HRS. HOWEVER...WITH DECENT LIFT SHOWN...WILL CODE UP
SOME HIGH CHC POPS OVERNIGHT AND KEEP A SMALL THUNDER THREAT IN.

CANT RULE OUT A FEW SVR CELLS THIS AFTN...MAINLY WIND. BUT
AGAIN...DOWNPOURS BIGGEST ISSUE.

FOR TEMPS...HEDGED TOWARD LAMP GUIDANCE ONCE AGAIN GIVEN ITS
RECENT PERFORMANCE. THIS RESULTED IN MINOR TWEAKS HERE AND THERE
FROM PREV FCST. GENERALLY LOW TO MID 80S ONCE AGAIN. LEANED ON
WARM SIDE TONIGHT GIVEN ABUNDANCE OF MOISTURE ABOUT THE AREA AND
SHRA THREAT.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
EXITING UPPER LEVEL LOW PROVIDING MARGINAL INSTABILITY OUT AHEAD OF
AN APPROACHING COLD FRONT LATE THURSDAY AND FRIDAY WITH HIGH
PRESSURE GRADUALLY BUILDING IN THROUGH THE DAY ON SATURDAY...MODELS
ARE IN SOME DISAGREEMENT WITH REGARD TO COVERAGE AND LOCATION OF
PREFRONTAL PRECIP OUT AHEAD OF THE COLD FRONT EARLY FRIDAY BUT
PRIMARILY WENT WITH THE NAM SOLUTION...LATER FRIDAY THE FRONT SLOWLY
MOVES SOUTH WITH AN UPPER LEVEL TROUGH AXIS HINTING TOWARD THE
POSSIBILITY OF SHOWERS IN THE TRI-STATE AREA...WENT WITH SLIGHT
CHANCE POPS...WITH THE UPPER RIDGE BUILDING BY SATURDAY AND THE
SURFACE HIGH DEVELOPING IN RESPONSE WE`LL WARM NICELY BUT DID KEEP
SLIGHT CHANCE POPS IN THE EASTERN MTNS WITH DIURNAL/OROGRAPHIC
FORCING.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS THROUGH THE LONG TERM
FORECAST. THE CENTER OF THE 500MB HIGH GENERALLY DRIFTS AROUND OVER
KS/OK/MO...WHICH KEEPS OUR REGION IN NW FLOW ALOFT...WITH SEVERAL
RIPPLES DROPPING THROUGH. TIMING/LOCATION OF EACH INDIVIDUAL WAVE
VARY BETWEEN GFS/ECMWF. SOME LOW LEVEL MOISTURE SHOULD BE AVAILABLE
WITH SE SURFACE FLOW...BUT JUST HOW MUCH WILL DEPEND ON WHERE
SURFACE HIGH IS. IF IT STAYS OVER THE SE STATES...WE WOULD GET AT
LEAST SOME MOISTURE ADVECTION FROM THE GULF...WHILE IF IT THE
SURFACE HIGH DRIFTS FARTHER WEST AS THE ECMWF HINTS...THAT RICHER
MOISTURE FLOW COULD GET CUT OF. DUE TO THIS UNCERTAINTY...STAYED
PRETTY CLOSE TO WPC GUIDANCE. WITH 500 HEIGHTS OVER 590DAM...LOOKS
LIKE A WARM STRETCH...WITH LOWLAND HIGHS IN THE UPPER 80S AND EVEN
SOME 90S NEXT WEEK. COULD ACTUALLY BE WARMER IF WE DO NOT HAVE THE
GOOD MOISTURE FLOW...AS THE DRIER AIR WOULD BE EASIER TO WARM.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z THURSDAY THRU 06Z FRIDAY...

UPR S/W TROF PUSHES E OF AREA AFTER 12Z. ISOLD SHRA THREAT THRU
MORNING...BUT CHC NOT GREAT ENOUGH TO INCLUDE IN TAFS. DIFFICULT FG
FCST THRU MORNING WITH VARIOUS AREAS OF HI CLDS...MAINLY ACROSS
THE N. ALSO A SLIGHT PUFF AT SFC TO COMPLICATE FG FORMATION
DESPITE RAINS YESTERDAY. PLAYED UP FG INITIALLY KCRW/KBKW BEFORE
TRYING TO LIFT OUT BY 09Z WITH EXPECTATION THAT HI CLDS MOVE IN
AND A SLIGHT SFC WIND BECOMES REALIZED. ELSEWHERE...ONLY HAVE MVFR
FG IN. THERE IS A CONCERN FOR SOME LOW STRATUS ACROSS KCKB AND
KEKN THRU MORNING BUT ELECTED TO LEAVE OUT OF TAFS ATTM AND FOLLOW
TRENDS FOR ANY AMENDMENTS.

FG LIFTS AFTER 12Z FOR A RETURN TO VFR CONDITIONS. HAVE SOME CU
FORMING BY MID MORNING WITH AREA IN BETWEEN WX SYS. EXPECT UPR
DISTURBANCE TO MAKE A RUN THRU AREA AFTER 18Z FROM NW...WELL AHEAD
OF SFC FRONT. AS SUCH...HAVE A PREDOMINATE SHRA/VCTS IN TAFS FOR
EXPECTED CONVECTIVE LINE IN AFTN. KEPT PREDOMINATE VFR THOUGH
GIVEN AT THIS RANGE.

THINGS MAY QUIET DOWN AFTER 00Z TONIGHT UNTIL SFC FRONT APPROACHES
WITH PERHAPS ANOTHER ROUND OF SHRA. NOT EXPECTING MUCH IN WAY OF
DENSE FG TONIGHT WITH ABUNDANCE OF CLDS ACROSS THE AREA.

SHOWERS AND THUNDERSTORMS WILL FIRE BACK UP AGAIN AFTER 16-18Z
THURSDAY AS A COLD FRONT APPROACHES FROM THE NORTH. EXPECT BRIEF
MVFR/IFR CONDITIONS IN VICINITY OF STORMS.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z FRIDAY...

FORECAST CONFIDENCE: MEDIUM.

ALTERNATE SCENARIOS: FOG MAY HOLD FOR CRW/BKW LONGER THAN
EXPECTED. MVFR STRATUS MAY DEVELOP FOR KCKB/KEKN THRU 12Z. TIMING
OF CONVECTION THIS AFTN MAY VARY A FEW HRS.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE                              THU 08/22/13
UTC 1HRLY       06   07   08   09   10   11   12   13   14   15   16   17
EDT 1HRLY       02   03   04   05   06   07   08   09   10   11   12   13
CRW CONSISTENCY  M    M    L    L    L    L    H    M    H    H    H    H
HTS CONSISTENCY  M    M    L    L    L    H    H    M    H    H    H    H
BKW CONSISTENCY  L    H    H    H    H    L    L    H    H    H    H    H
EKN CONSISTENCY  L    L    L    L    L    L    L    H    H    H    H    H
PKB CONSISTENCY  H    H    L    L    L    L    H    H    H    H    H    H
CKB CONSISTENCY  L    L    L    L    L    H    H    H    H    H    H    H

AFTER 06Z FRIDAY...
AREAS OF IFR IN DENSE FOG/LOW STRATUS MOST MORNINGS THIS
WEEK...ESPECIALLY ALONG THE RIVERS.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...JM
LONG TERM...MZ
AVIATION...30









AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 759 AM EDT THU AUG 22 2013

.SYNOPSIS...
AN UPPER LOW...CENTERED OVER THE LAUREL HIGHLANDS...WILL DRIFT
ACROSS THE SOUTHERN TIER OF PENNSYLVANIA THIS MORNING. WEAK RIDGING
IN THE WAKE OF THIS LOW WILL BE OVER THE REGION DURING THE MIDDAY
AND AFTERNOON HOURS...ACCOMPANIED BY GENERALLY FAIR WEATHER. A COLD
FRONT WILL PUSH SOUTHEAST ACROSS THE REGION LATE THURSDAY INTO EARLY
FRIDAY...FOLLOWED BY CANADIAN HIGH PRESSURE.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL IR SATELLITE AND RADAR LOOP AT 0815Z SHOWS EXPANDING
COVERAGE OF SHOWERS AND A FEW TSRA FROM THE LAUREL HIGHLANDS...EAST
TO THE LOWER SUSQ VALLEY. THIS CONVECTION WAS OCCURRING WITHIN A
REGION OF MDTLY STRONG UPPER DIFFLUENCE AND DIFFERENTIAL PVA JUST
AHEAD OF A SLOW-MOVING UPPER LOW. ALSO AIDING THIS CONVECTION WAS
THE VERY JUICY AIRMASS WITH LAYER PWATS IN THE 1.5-2 INCH
RANGE...ALONG WITH STRENGTHENING 850-700 MB FRONTOGENESIS.

LATEST HRRR AND RUC CONTINUES TO PAINT LIGHT TO MODERATE RAINFALL
AMOUNTS OVER THE NEXT SEVERAL HOURS ACROSS APPROXIMATELY THE
SOUTHERN 1/3 TO 1/2 OF THE CWA AS THE UPPER LOW TRACKS SLOWLY EAST
AND PROVIDES LIFT OF THE VERY MOIST AND UNSTABLE AIR. MOST OF THE
SHOWERS AND EMBEDDED TSRA WILL BE NEAR AND JUST TO THE SOUTH OF A
LINE FROM KAOO TO KSEG AND KAVP...BEFORE FOCUSING OVER THE ECENT
MTNS /SCHUYLKILL CTY AND VCNTY/ BETWEEN 10-13Z.

SFC DWPTS RANGE FROM THE U60S AND L70S IN THE SOUTH....TO THE UPPER
50S AND LOWER 60S IN THE NORTH...WHERE THE BLYR WILL LIKELY REMAIN
TOO DRY TO SUPPORT ANY CONVECTION.

EXTENSIVE CLOUD COVER AND LOW LVL MOISTURE WILL RESULT IN THE
WARMEST EARLY MORNING IN SOME TIME WITH LOWS RANGING FROM THE UPPER
50S OVR THE N MTNS...TO ARND 70F ACROSS THE LOWER SUSQ VALLEY.

THE REMNANTS OF UPPER LOW SHOULD TAKE UNTIL ARND MIDDAY TO CLEAR THE
ERN...SO WILL CARRY A CHC POPS FOR SHRA/TSRA THERE UNTIL THAT
TIME. RIDGING IN WAKE OF DEPARTING UPPER LOW SHOULD BRING A PERIOD
OF DRY CONDITIONS TO MOST OF CENTRAL PENN ON THURS BEFORE COLD FRONT
FROM THE GLAKES BRINGS ANOTHER THREAT OF CONVECTION LATE IN THE DAY
NW /AND MORE LIKELY BEGINNING THIS EVENING ACROSS THE CENTRAL MTNS/.

A RIBBON OF HIGHER PWATS BETWEEN 1.5 AND 1.75 INCHES AND SLIGHTLY
STEEPER MID-LEVEL LAPSE RATES SHOULD SUPPORT SCT SHRA/TSRA
DEVELOPING ACROSS THE NW MTNS /AHEAD OF A COLD FRONT/ DURING THE MID
TO LATE AFTN...WITH THE CONVECTION SLIDING SE THRU THE REST OF THE
REGION BETWEEN 02-06Z FRIDAY.

HIGH TEMPS THIS AFTERNOON WILL REACH THE MID AND UPPER 80S ACROSS
THE CENTRAL AND SE VALLEYS...AND AROUND 80F OVER THE HIGHER TERRAIN
OF NRN AND WRN PENN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
AS NOTED ABOVE...THE TIMING OF THE SFC COLD FRONT AND ASSOCIATED
SHRA/TSRA WILL BE DURING THE FIRST HALF OF THE OVERNIGHT HOURS.
POPS WILL DIMINISH STEADILY AFTER MIDNIGHT AND BECOME CONFINED TO
THE SOUTHERN TIER OF THE STATE BEFORE DAYBREAK.

THE MEAN LOW-MID LEVEL FLOW VEERS AROUND TO THE NNW FRIDAY...
ALLOWING DEEP DRYING TO ADVECT INTO THE REGION DURING THE DAY. MAX
TEMPS FRIDAY WILL COOL BY A FEW TO SVRL DEG F COMPARED TO THURSDAY/S.

SFC DEWPOINTS WILL RETREAT BACK TO VERY COMFORTABLE LEVELS IN THE
UPPER 40S /NW/...AND MID 50S /SE/ FRIDAY AFTERNOON...SETTING THE
STAGE FOR A COOL LATE AUGUST NIGHT FRIDAY NIGHT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW...THE LATEST MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY
GOOD AGREEMENT IN THE LARGE SCALE MEAN FLOW PATTERN CONSISTING OF
A BUILDING/STRONG UPPER RIDGE OVER THE PLAINS/MS VLY WITH TROUGHS
JUST OFF THE WEST AND EAST COASTS. HOWEVER...THE PCPN PATTERN OVER
THE LOCAL AREA WILL BE MODULATED BY SHORTWV IMPULSES DIVING ESEWD
DOWN THE NERN/FRONT SIDE OF THE RIDGE WITHIN A NWLY FLOW ALOFT.
THEREFORE DESPITE ABOVE AVG CONFIDENCE IN THE MEAN PATTERN...THE
SMALLER SCALE EMBEDDED SYSTEM TIMING AND LOCAL QPF/SENSIBLE WX
IMPACT IS MORE UNCERTAIN. AS SUCH...THE FINAL DAY 3-7 GRIDS WERE
DERIVED USING A CONSENSUS BLEND IN AN EFFORT TO MITIGATE THE LOWER
CONFIDENCE IN THE SFC DETAILS AND TO BEHOLD REASONABLE CONTINUITY
THE FCST.

A MODIFIED CANADIAN HIGH PRESSURE SYSTEM WILL DOMINATE THE PATTERN
THROUGH THE WEEKEND...BRINGING RELATIVELY COOL NIGHTS WITH VALLEY
FOG AND COMFORTABLE HUMIDITY DURING THE DAY. EXPECT A MORE UNSETTLED
AND INCREASINGLY HUMID PATTERN TO EVOLVE THRU THE FIRST PART OF NEXT
WEEK..AS THE FOCUS SHIFTS TO UPPER-LEVEL DISTURBANCES CRESTING THE
PLAINS RIDGE AND DIVING ESEWD THRU THE GREAT LAKES TAKING AIM ON THE
NE STATES. MODELS SUGGEST THIS ENERGY MAY TRIGGER ONE OR MORE
ORGANIZED TSTM COMPLEXES AS THEY ROLL DOWN THE FRONT-SIDE OF THE
RIDGE.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...

IFR CIGS AND VSBYS AT BFD...AND MVFR CIGS AND VSBYS AT JST AND IPT
DUE TO PATCHY FOG/MIST WILL CONTINUE THROUGH 14Z BEFORE
LIFTING/DISSIPATING BY 14Z. AFTER THAT LIFTS VFR CONDITIONS WILL
DOMINATE MOST THE DAY.

AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL MOVE THROUGH
THE REGION LATE THIS AFTERNOON THROUGH TONIGHT. THIS WILL BRING A
BETTER CHC FOR SHRA/TSRA. THIS FRONT SHOULD PASS SOUTH OF THE
REGION OVERNIGHT TONIGHT. PATCHY FOG DUE TO CLEARING SKIES AND
CALM WINDS BEHIND THE FRONT IS POSSIBLE INTO FRIDAY MORNING.
OTHERWISE IMPROVING FLYING CONDS FOR FRIDAY INTO THIS WEEKEND. WITH
VARYING TIMING...HAVE ONLY INCLUDED VCSH IN TAFS...BUT REDUCTION
IN CIG AND VSBYS WILL BE POSSIBLE.

OUTLOOK...

THU-THU NIGHT...MVFR POSSIBLE WITH SCT SHRA/TSRA.
FRI-MON...GENERALLY VFR.

&&

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

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...LAMBERT/STEINBUGL
AVIATION...CERU







AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 631 AM EDT THU AUG 22 2013

.SYNOPSIS...
AN UPPER LOW...CENTERED OVER THE LAUREL HIGHLANDS...WILL DRIFT
ACROSS THE SOUTHERN TIER OF PENNSYLVANIA THIS MORNING. WEAK RIDGING
IN THE WAKE OF THIS LOW WILL BE OVER THE REGION DURING THE MIDDAY
AND AFTERNOON HOURS...ACCOMPANIED BY GENERALLY FAIR WEATHER. A COLD
FRONT WILL PUSH SOUTHEAST ACROSS THE REGION LATE THURSDAY INTO EARLY
FRIDAY...FOLLOWED BY CANADIAN HIGH PRESSURE.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL IR SATELLITE AND RADAR LOOP AT 0815Z SHOWS EXPANDING
COVERAGE OF SHOWERS AND A FEW TSRA FROM THE LAUREL HIGHLANDS...EAST
TO THE LOWER SUSQ VALLEY. THIS CONVECTION WAS OCCURRING WITHIN A
REGION OF MDTLY STRONG UPPER DIFFLUENCE AND DIFFERENTIAL PVA JUST
AHEAD OF A SLOW-MOVING UPPER LOW. ALSO AIDING THIS CONVECTION WAS
THE VERY JUICY AIRMASS WITH LAYER PWATS IN THE 1.5-2 INCH
RANGE...ALONG WITH STRENGTHENING 850-700 MB FRONTOGENESIS.

LATEST HRRR AND RUC CONTINUES TO PAINT LIGHT TO MODERATE RAINFALL
AMOUNTS OVER THE NEXT SEVERAL HOURS ACROSS APPROXIMATELY THE
SOUTHERN 1/3 TO 1/2 OF THE CWA AS THE UPPER LOW TRACKS SLOWLY EAST
AND PROVIDES LIFT OF THE VERY MOIST AND UNSTABLE AIR. MOST OF THE
SHOWERS AND EMBEDDED TSRA WILL BE NEAR AND JUST TO THE SOUTH OF A
LINE FROM KAOO TO KSEG AND KAVP...BEFORE FOCUSING OVER THE ECENT
MTNS /SCHUYLKILL CTY AND VCNTY/ BETWEEN 10-13Z.

SFC DWPTS RANGE FROM THE U60S AND L70S IN THE SOUTH....TO THE UPPER
50S AND LOWER 60S IN THE NORTH...WHERE THE BLYR WILL LIKELY REMAIN
TOO DRY TO SUPPORT ANY CONVECTION.

EXTENSIVE CLOUD COVER AND LOW LVL MOISTURE WILL RESULT IN THE
WARMEST EARLY MORNING IN SOME TIME WITH LOWS RANGING FROM THE UPPER
50S OVR THE N MTNS...TO ARND 70F ACROSS THE LOWER SUSQ VALLEY.

THE REMNANTS OF UPPER LOW SHOULD TAKE UNTIL ARND MIDDAY TO CLEAR THE
ERN...SO WILL CARRY A CHC POPS FOR SHRA/TSRA THERE UNTIL THAT
TIME. RIDGING IN WAKE OF DEPARTING UPPER LOW SHOULD BRING A PERIOD
OF DRY CONDITIONS TO MOST OF CENTRAL PENN ON THURS BEFORE COLD FRONT
FROM THE GLAKES BRINGS ANOTHER THREAT OF CONVECTION LATE IN THE DAY
NW /AND MORE LIKELY BEGINNING THIS EVENING ACROSS THE CENTRAL MTNS/.

A RIBBON OF HIGHER PWATS BETWEEN 1.5 AND 1.75 INCHES AND SLIGHTLY
STEEPER MID-LEVEL LAPSE RATES SHOULD SUPPORT SCT SHRA/TSRA
DEVELOPING ACROSS THE NW MTNS /AHEAD OF A COLD FRONT/ DURING THE MID
TO LATE AFTN...WITH THE CONVECTION SLIDING SE THRU THE REST OF THE
REGION BETWEEN 02-06Z FRIDAY.

HIGH TEMPS THIS AFTERNOON WILL REACH THE MID AND UPPER 80S ACROSS
THE CENTRAL AND SE VALLEYS...AND AROUND 80F OVER THE HIGHER TERRAIN
OF NRN AND WRN PENN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
AS NOTED ABOVE...THE TIMING OF THE SFC COLD FRONT AND ASSOCIATED
SHRA/TSRA WILL BE DURING THE FIRST HALF OF THE OVERNIGHT HOURS.
POPS WILL DIMINISH STEADILY AFTER MIDNIGHT AND BECOME CONFINED TO
THE SOUTHERN TIER OF THE STATE BEFORE DAYBREAK.

THE MEAN LOW-MID LEVEL FLOW VEERS AROUND TO THE NNW FRIDAY...
ALLOWING DEEP DRYING TO ADVECT INTO THE REGION DURING THE DAY. MAX
TEMPS FRIDAY WILL COOL BY A FEW TO SVRL DEG F COMPARED TO THURSDAY/S.

SFC DEWPOINTS WILL RETREAT BACK TO VERY COMFORTABLE LEVELS IN THE
UPPER 40S /NW/...AND MID 50S /SE/ FRIDAY AFTERNOON...SETTING THE
STAGE FOR A COOL LATE AUGUST NIGHT FRIDAY NIGHT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW...THE LATEST MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY
GOOD AGREEMENT IN THE LARGE SCALE MEAN FLOW PATTERN CONSISTING OF
A BUILDING/STRONG UPPER RIDGE OVER THE PLAINS/MS VLY WITH TROUGHS
JUST OFF THE WEST AND EAST COASTS. HOWEVER...THE PCPN PATTERN OVER
THE LOCAL AREA WILL BE MODULATED BY SHORTWV IMPULSES DIVING ESEWD
DOWN THE NERN/FRONT SIDE OF THE RIDGE WITHIN A NWLY FLOW ALOFT.
THEREFORE DESPITE ABOVE AVG CONFIDENCE IN THE MEAN PATTERN...THE
SMALLER SCALE EMBEDDED SYSTEM TIMING AND LOCAL QPF/SENSIBLE WX
IMPACT IS MORE UNCERTAIN. AS SUCH...THE FINAL DAY 3-7 GRIDS WERE
DERIVED USING A CONSENSUS BLEND IN AN EFFORT TO MITIGATE THE LOWER
CONFIDENCE IN THE SFC DETAILS AND TO BEHOLD REASONABLE CONTINUITY
THE FCST.

A MODIFIED CANADIAN HIGH PRESSURE SYSTEM WILL DOMINATE THE PATTERN
THROUGH THE WEEKEND...BRINGING RELATIVELY COOL NIGHTS WITH VALLEY
FOG AND COMFORTABLE HUMIDITY DURING THE DAY. EXPECT A MORE UNSETTLED
AND INCREASINGLY HUMID PATTERN TO EVOLVE THRU THE FIRST PART OF NEXT
WEEK..AS THE FOCUS SHIFTS TO UPPER-LEVEL DISTURBANCES CRESTING THE
PLAINS RIDGE AND DIVING ESEWD THRU THE GREAT LAKES TAKING AIM ON THE
NE STATES. MODELS SUGGEST THIS ENERGY MAY TRIGGER ONE OR MORE
ORGANIZED TSTM COMPLEXES AS THEY ROLL DOWN THE FRONT-SIDE OF THE
RIDGE.

&&

.AVIATION /10Z THURSDAY THROUGH MONDAY/...
SHOWERS HAVE MOVED TO THE NORTHEAST...WITH ONLY MVFR VSBYS FROM
PATCHY MIST/FOG AT BFD. ANY PATCHY FOG WILL LIFT/DISSIPATE BY 14Z.
MAINLY VFR THROUGHOUT THE DAY.

AN APPROACHING COLD FRONT FROM THE GREAT LAKES WILL MOVE THROUGH
THE REGION LATE THIS AFTERNOON THROUGH TONIGHT. THIS WILL BRING A
BETTER CHC FOR SHRA/TSRA. THIS FRONT SHOULD PASS SOUTH OF THE
REGION OVERNIGHT TONIGHT. PATCHY FOG DUE TO CLEARING SKIES AND
CALM WINDS BEHIND THE FRONT IS POSSIBLE INTO FRIDAY MORNING.
OTHERWISE IMPROVING FLYING CONDS FOR FRIDAY INTO THIS WEEKEND. WITH
VARYING TIMING...HAVE ONLY INCLUDED VCSH IN TAFS...BUT REDUCTION
IN CIG AND VSBYS WILL BE POSSIBLE.

OUTLOOK...

THU-THU NIGHT...MVFR POSSIBLE WITH SCT SHRA/TSRA.
FRI-MON...GENERALLY VFR.

&&

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

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...LAMBERT/STEINBUGL
AVIATION...CERU







AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 425 AM EDT THU AUG 22 2013

.SYNOPSIS...
AN UPPER LOW...CENTERED OVER THE LAUREL HIGHLANDS...WILL DRIFT
ACROSS THE SOUTHERN TIER OF PENNSYLVANIA THIS MORNING. WEAK RIDGING
IN THE WAKE OF THIS LOW WILL BE OVER THE REGION DURING THE MIDDAY
AND AFTERNOON HOURS...ACCOMPANIED BY GENERALLY FAIR WEATHER. A COLD
FRONT WILL PUSH SOUTHEAST ACROSS THE REGION LATE THURSDAY INTO EARLY
FRIDAY...FOLLOWED BY CANADIAN HIGH PRESSURE.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL IR SATELLITE AND RADAR LOOP AT 0815Z SHOWS EXPANDING
COVERAGE OF SHOWERS AND A FEW TSRA FROM THE LAUREL HIGHLANDS...EAST
TO THE LOWER SUSQ VALLEY. THIS CONVECTION WAS OCCURRING WITHIN A
REGION OF MDTLY STRONG UPPER DIFFLUENCE AND DIFFERENTIAL PVA JUST
AHEAD OF A SLOW-MOVING UPPER LOW. ALSO AIDING THIS CONVECTION WAS
THE VERY JUICY AIRMASS WITH LAYER PWATS IN THE 1.5-2 INCH
RANGE...ALONG WITH STRENGTHENING 850-700 MB FRONTOGENESIS.

LATEST HRRR AND RUC CONTINUES TO PAINT LIGHT TO MODERATE RAINFALL
AMOUNTS OVER THE NEXT SEVERAL HOURS ACROSS APPROXIMATELY THE
SOUTHERN 1/3 TO 1/2 OF THE CWA AS THE UPPER LOW TRACKS SLOWLY EAST
AND PROVIDES LIFT OF THE VERY MOIST AND UNSTABLE AIR. MOST OF THE
SHOWERS AND EMBEDDED TSRA WILL BE NEAR AND JUST TO THE SOUTH OF A
LINE FROM KAOO TO KSEG AND KAVP...BEFORE FOCUSING OVER THE ECENT
MTNS /SCHUYLKILL CTY AND VCNTY/ BETWEEN 10-13Z.

SFC DWPTS RANGE FROM THE U60S AND L70S IN THE SOUTH....TO THE UPPER
50S AND LOWER 60S IN THE NORTH...WHERE THE BLYR WILL LIKELY REMAIN
TOO DRY TO SUPPORT ANY CONVECTION.

EXTENSIVE CLOUD COVER AND LOW LVL MOISTURE WILL RESULT IN THE
WARMEST EARLY MORNING IN SOME TIME WITH LOWS RANGING FROM THE UPPER
50S OVR THE N MTNS...TO ARND 70F ACROSS THE LOWER SUSQ VALLEY.

THE REMNANTS OF UPPER LOW SHOULD TAKE UNTIL ARND MIDDAY TO CLEAR THE
ERN...SO WILL CARRY A CHC POPS FOR SHRA/TSRA THERE UNTIL THAT
TIME. RIDGING IN WAKE OF DEPARTING UPPER LOW SHOULD BRING A PERIOD
OF DRY CONDITIONS TO MOST OF CENTRAL PENN ON THURS BEFORE COLD FRONT
FROM THE GLAKES BRINGS ANOTHER THREAT OF CONVECTION LATE IN THE DAY
NW /AND MORE LIKELY BEGINNING THIS EVENING ACROSS THE CENTRAL MTNS/.

A RIBBON OF HIGHER PWATS BETWEEN 1.5 AND 1.75 INCHES AND SLIGHTLY
STEEPER MID-LEVEL LAPSE RATES SHOULD SUPPORT SCT SHRA/TSRA
DEVELOPING ACROSS THE NW MTNS /AHEAD OF A COLD FRONT/ DURING THE MID
TO LATE AFTN...WITH THE CONVECTION SLIDING SE THRU THE REST OF THE
REGION BETWEEN 02-06Z FRIDAY.

HIGH TEMPS THIS AFTERNOON WILL REACH THE MID AND UPPER 80S ACROSS
THE CENTRAL AND SE VALLEYS...AND AROUND 80F OVER THE HIGHER TERRAIN
OF NRN AND WRN PENN.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
AS NOTED ABOVE...THE TIMING OF THE SFC COLD FRONT AND ASSOCIATED
SHRA/TSRA WILL BE DURING THE FIRST HALF OF THE OVERNIGHT HOURS.
POPS WILL DIMINISH STEADILY AFTER MIDNIGHT AND BECOME CONFINED TO
THE SOUTHERN TIER OF THE STATE BEFORE DAYBREAK.

THE MEAN LOW-MID LEVEL FLOW VEERS AROUND TO THE NNW FRIDAY...
ALLOWING DEEP DRYING TO ADVECT INTO THE REGION DURING THE DAY. MAX
TEMPS FRIDAY WILL COOL BY A FEW TO SVRL DEG F COMPARED TO THURSDAY/S.

SFC DEWPOINTS WILL RETREAT BACK TO VERY COMFORTABLE LEVELS IN THE
UPPER 40S /NW/...AND MID 50S /SE/ FRIDAY AFTERNOON...SETTING THE
STAGE FOR A COOL LATE AUGUST NIGHT FRIDAY NIGHT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW...THE LATEST MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY
GOOD AGREEMENT IN THE LARGE SCALE MEAN FLOW PATTERN CONSISTING OF
A BUILDING/STRONG UPPER RIDGE OVER THE PLAINS/MS VLY WITH TROUGHS
JUST OFF THE WEST AND EAST COASTS. HOWEVER...THE PCPN PATTERN OVER
THE LOCAL AREA WILL BE MODULATED BY SHORTWV IMPULSES DIVING ESEWD
DOWN THE NERN/FRONT SIDE OF THE RIDGE WITHIN A NWLY FLOW ALOFT.
THEREFORE DESPITE ABOVE AVG CONFIDENCE IN THE MEAN PATTERN...THE
SMALLER SCALE EMBEDDED SYSTEM TIMING AND LOCAL QPF/SENSIBLE WX
IMPACT IS MORE UNCERTAIN. AS SUCH...THE FINAL DAY 3-7 GRIDS WERE
DERIVED USING A CONSENSUS BLEND IN AN EFFORT TO MITIGATE THE LOWER
CONFIDENCE IN THE SFC DETAILS AND TO BEHOLD REASONABLE CONTINUITY
THE FCST.

A MODIFIED CANADIAN HIGH PRESSURE SYSTEM WILL DOMINATE THE PATTERN
THROUGH THE WEEKEND...BRINGING RELATIVELY COOL NIGHTS WITH VALLEY
FOG AND COMFORTABLE HUMIDITY DURING THE DAY. EXPECT A MORE UNSETTLED
AND INCREASINGLY HUMID PATTERN TO EVOLVE THRU THE FIRST PART OF NEXT
WEEK..AS THE FOCUS SHIFTS TO UPPER-LEVEL DISTURBANCES CRESTING THE
PLAINS RIDGE AND DIVING ESEWD THRU THE GREAT LAKES TAKING AIM ON THE
NE STATES. MODELS SUGGEST THIS ENERGY MAY TRIGGER ONE OR MORE
ORGANIZED TSTM COMPLEXES AS THEY ROLL DOWN THE FRONT-SIDE OF THE
RIDGE.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
SOUTHERLY FLOW CONTINUES TO SPARK SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS THE SOUTHERN HALF OF PA OVERNIGHT.
EXPECT VCTS IN MDT AND LNS...WITH SHOWERS AT JST. THE SHOWERS AND
JST SHOULD REDUCE CIGS AND VSBYS TO MVFR FOR A FEW HOURS...BEFORE
LIFTING NORTHWARD BY 09Z. ANY PRECIPITATION WILL REINFORCE LOW
LEVEL MOISTURE WHICH GIVEN THE CALMING WINDS...COULD ALLOW FOR
PATCHY FOG FROM 10Z THROUGH 14Z. AN APPROACHING COLD FRONT FROM
THE GREAT LAKES TODAY WILL ALLOW FOR A BETTER CHC FOR SHRA/TSRA.
THIS FRONT SHOULD PASS SOUTH OF THE REGION THURSDAY NIGHT...WITH
IMPROVING FLYING CONDS FOR FRI INTO THIS WEEKEND.
WITH VARYING TIMING...HAVE ONLY INCLUDED VCSH IN TAFS...BUT
REDUCTION IN CIG AND VSBYS WILL BE POSSIBLE.

OUTLOOK...

THU-THU NIGHT...MVFR POSSIBLE WITH SCT SHRA/TSRA.
FRI-MON...GENERALLY VFR.

&&

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

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/STEINBUGL
AVIATION...CERU/GARTNER










AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 316 AM EDT THU AUG 22 2013

.SYNOPSIS...
AN UPPER LOW...NEAR MORGANTOWN WEST VIRGINIA...WILL DRIFT ACROSS THE
SOUTHERN TIER OF PENNSYLVANIA EARLY TODAY. WEAK RIDGING IN THE WAKE
OF THIS LOW WILL BE OVER THE REGION LATER THIS MORNING THROUGH THE
AFTERNOON HOURS...ACCOMPANIED BY GENERALLY FAIR WEATHER. A COLD
FRONT WILL PUSH SOUTHEAST ACROSS THE REGION LATE THURSDAY INTO EARLY
FRIDAY...FOLLOWED BY CANADIAN HIGH PRESSURE.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REGIONAL IR SATELLITE AND RADAR LOOP SHOWS A CLUSTER OF SHOWERS AND
LOW-TOPPED TSRA DEVELOPING INVOF THE LAUREL HIGHLANDS...SOUTH INTO
THE MTNS OF WVA AT 05Z...WITHIN A REGION OF MDTLY STRONG UPPER
DIFFLUENCE AND DIFFERENTIAL PVA JUST AHEAD OF A SLOW-MOVING UPPER
LOW.

LATEST HRRR SHOWS THIS AREA OF CONVECTION BLOSSOMING TO THE
NORTHEAST ACROSS THE SCENT MTNS THROUGH DAYBREAK...REACHING THE I-80
CORRIDOR THROUGH THE MIDDLE SUSQ VALLEY AROUND AND SHORTLY AFTER
SUNRISE. 04Z RUC ALSO SHOWING SIGNS OF THIS POTENTIAL DVLPMT AND
TRACK OF CONVECTION EARLY TODAY...BASED ON IT/S WELL-DEFINED CHANNEL
OF 925-850 MB THETA-E CONVERGENCE SETTING UP NEAR AND JUST TO THE SE
OF A KJST TO KUNV AND KIPT LINE. MID LEVEL LAPSE RATES ARE ALSO
STEEPENING IN THIS AREA THROUGH THE MORNING HOURS...AND CAN BE SEEN
IN THE MOST UNSTABLE AIR WITH CURRENT...MU CAPE OF 1200-1500 J/KG IN
THE REGION BETWEEN KJST...KAOO...KUNV...AND KFIG.

CONSIDERING ALL OF THESE NEAR TERM WEATHER FACTORS...WILL BE
BOOSTING POPS TO REFLECT A BLEND OF ALL HIGH RES/NEAR TERM MODEL
GUIDANCE...THOUGH QPF WILL BE SIGNIFICANTLY UNDER THE LOCALLY
EXCESSIVE CONVECTIVE AMOUNTS /OF 1-3 INCHES/ GENERATED BY THESE
MODELS.

A SECOND AREA OF HEAVIER CONVECTION SHOULD SLIDE OFF WELL TO THE
SOUTH OF YORK AND LANCASTER COUNTIES THROUGH THE MID MORNING...WITH
THE LOWER SUSQ VALLEY SEEING ISOLATED TO SCTD SHOWERS BETWEEN
07-12Z.

SFC DWPTS RANGE FROM THE U60S AND L70S IN THE SOUTH....TO THE UPPER
50S AND LOWER 60S IN THE NORTH...WHERE THE BLYR WILL LIKELY REMAIN
TOO DRY TO SUPPORT ANY CONVECTION.

EXTENSIVE CLOUD COVER AND LOW LVL MOISTURE WILL RESULT IN THE
WARMEST NIGHT/EARLY MORNING IN SOME TIME WITH LOWS RANGING FROM ARND
60F OVR THE N MTNS...TO ARND 70F ACROSS THE LOWER SUSQ VALLEY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
REMNANTS OF UPPER LOW SHOULD TAKE UNTIL ARND MIDDAY TO CLEAR THE
SE COUNTIES...SO WILL CARRY A SLIGHT CHC OF A SHRA/TSRA DOWN THERE
UNTIL THAT TIME. RIDGING IN WAKE OF DEPARTING UPPER LOW SHOULD
BRING A PERIOD OF DRY CONDITIONS TO MOST OF CENTRAL PENN ON THURS
BEFORE COLD FRONT FROM THE GLAKES BRINGS ANOTHER THREAT OF
CONVECTION LATE IN THE DAY.

A RIBBON OF HIGHER PWATS BETWEEN 1.5 AND 1.75 INCHES AND SLIGHTLY
STEEPER MID-LEVEL LAPSE RATES SHOULD SUPPORT SCT SHRA/TSRA
DEVELOPING ACROSS THE NW MTNS THURSDAY AFTN AND SLIDING SE THRU
THE EVENING AND EARLY OVERNIGHT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW...THE LATEST MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY
GOOD AGREEMENT IN THE LARGE SCALE MEAN FLOW PATTERN CONSISTING OF
A BUILDING/STRONG UPPER RIDGE OVER THE PLAINS/MS VLY WITH TROUGHS
JUST OFF THE WEST AND EAST COASTS. HOWEVER...THE PCPN PATTERN OVER
THE LOCAL AREA WILL BE MODULATED BY SHORTWV IMPULSES DIVING ESEWD
DOWN THE NERN/FRONT SIDE OF THE RIDGE WITHIN A NWLY FLOW ALOFT.
THEREFORE DESPITE ABOVE AVG CONFIDENCE IN THE MEAN PATTERN...THE
SMALLER SCALE EMBEDDED SYSTEM TIMING AND LOCAL QPF/SENSIBLE WX
IMPACT IS MORE UNCERTAIN. AS SUCH...THE FINAL DAY 3-7 GRIDS WERE
DERIVED USING A CONSENSUS BLEND IN AN EFFORT TO MITIGATE THE LOWER
CONFIDENCE IN THE SFC DETAILS AND TO BEHOLD REASONABLE CONTINUITY
THE FCST.

HIGHLIGHTS...PUSH OF ABNORMALLY DRY AIR WITH BELOW NORMAL PWS
BEHIND THE THUR NGT FROPA APPEARS DELAYED BY ABOUT 6 HRS ON THE
12Z CYCLE...SUGGESTING A LOW CHC FOR SHOWERS ALONG THE SRN TIER
ZONES EARLY FRI. OTHERWISE...A MODIFIED CANADIAN HIGH PRESSURE
SYSTEM WILL DOMINATE THE PATTERN THROUGH THE WEEKEND..BRINGING
RELATIVELY COOL NIGHTS WITH VALLEY FOG AND COMFORTABLE HUMIDITY
DURING THE DAY. EXPECT A MORE UNSETTLED AND INCREASINGLY HUMID
PATTERN TO EVOLVE THRU THE FIRST PART OF NEXT WEEK..AS THE FOCUS
SHIFTS TO UPPER-LEVEL DISTURBANCES CRESTING THE PLAINS RIDGE AND
DIVING ESEWD THRU THE GREAT LAKES TAKING AIM ON THE NE STATES.
MODELS SUGGEST THIS ENERGY MAY TRIGGER ONE OR MORE ORGANIZED TSTM
COMPLEXES AS THEY ROLL DOWN THE FRONT-SIDE OF THE RIDGE.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
SOUTHERLY FLOW CONTINUES TO SPARK SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ACROSS THE SOUTHERN HALF OF PA OVERNIGHT.
EXPECT VCTS IN MDT AND LNS...WITH SHOWERS AT JST. THE SHOWERS AND
JST SHOULD REDUCE CIGS AND VSBYS TO MVFR FOR A FEW HOURS...BEFORE
LIFTING NORTHWARD BY 09Z. ANY PRECIPITATION WILL REINFORCE LOW
LEVEL MOISTURE WHICH GIVEN THE CALMING WINDS...COULD ALLOW FOR
PATCHY FOG FROM 10Z THROUGH 14Z. AN APPROACHING COLD FRONT FROM
THE GREAT LAKES TODAY WILL ALLOW FOR A BETTER CHC FOR SHRA/TSRA.
THIS FRONT SHOULD PASS SOUTH OF THE REGION THURSDAY NIGHT...WITH
IMPROVING FLYING CONDS FOR FRI INTO THIS WEEKEND.
WITH VARYING TIMING...HAVE ONLY INCLUDED VCSH IN TAFS...BUT
REDUCTION IN CIG AND VSBYS WILL BE POSSIBLE.

OUTLOOK...

THU-THU NIGHT...MVFR POSSIBLE WITH SCT SHRA/TSRA.
FRI-MON...GENERALLY VFR.

&&

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

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...LAMBERT/STEINBUGL
AVIATION...CERU/GARTNER







AREA FORECAST DISCUSSION

NWS STATE COLLEGE PA

 105 AM EDT THU AUG 22 2013

.SYNOPSIS...
AN UPPER LOW...NEAR MORGANTOWN WEST VIRGINIA...WILL DRIFT ACROSS THE
SOUTHERN TIER OF PENNSYLVANIA EARLY TODAY. WEAK RIDGING IN THE WAKE
OF THIS LOW WILL BE OVER THE REGION LATER THIS MORNING THROUGH THE
AFTERNOON HOURS...ACCOMPANIED BY GENERALLY FAIR WEATHER. A COLD
FRONT WILL PUSH SOUTHEAST ACROSS THE REGION LATE THURSDAY INTO EARLY
FRIDAY...FOLLOWED BY CANADIAN HIGH PRESSURE.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
REGIONAL IR SATELLITE AND RADAR LOOP SHOWS A CLUSTER OF SHOWERS AND
LOW-TOPPED TSRA DEVELOPING INVOF THE LAUREL HIGHLANDS...SOUTH INTO
THE MTNS OF WVA AT 05Z...WITHIN A REGION OF MDTLY STRONG UPPER
DIFFLUENCE AND DIFFERENTIAL PVA JUST AHEAD OF A SLOW-MOVING UPPER
LOW.

LATEST HRRR SHOWS THIS AREA OF CONVECTION BLOSSOMING TO THE
NORTHEAST ACROSS THE SCENT MTNS THROUGH DAYBREAK...REACHING THE I-80
CORRIDOR THROUGH THE MIDDLE SUSQ VALLEY AROUND AND SHORTLY AFTER
SUNRISE. 04Z RUC ALSO SHOWING SIGNS OF THIS POTENTIAL DVLPMT AND
TRACK OF CONVECTION EARLY TODAY...BASED ON IT/S WELL-DEFINED CHANNEL
OF 925-850 MB THETA-E CONVERGENCE SETTING UP NEAR AND JUST TO THE SE
OF A KJST TO KUNV AND KIPT LINE. MID LEVEL LAPSE RATES ARE ALSO
STEEPENING IN THIS AREA THROUGH THE MORNING HOURS...AND CAN BE SEEN
IN THE MOST UNSTABLE AIR WITH CURRENT...MU CAPE OF 1200-1500 J/KG IN
THE REGION BETWEEN KJST...KAOO...KUNV...AND KFIG.

CONSIDERING ALL OF THESE NEAR TERM WEATHER FACTORS...WILL BE
BOOSTING POPS TO REFLECT A BLEND OF ALL HIGH RES/NEAR TERM MODEL
GUIDANCE...THOUGH QPF WILL BE SIGNIFICANTLY UNDER THE LOCALLY
EXCESSIVE CONVECTIVE AMOUNTS /OF 1-3 INCHES/ GENERATED BY THESE
MODELS.

A SECOND AREA OF HEAVIER CONVECTION SHOULD SLIDE OFF WELL TO THE
SOUTH OF YORK AND LANCASTER COUNTIES THROUGH THE MID MORNING...WITH
THE LOWER SUSQ VALLEY SEEING ISOLATED TO SCTD SHOWERS BETWEEN
07-12Z.

SFC DWPTS RANGE FROM THE U60S AND L70S IN THE SOUTH....TO THE UPPER
50S AND LOWER 60S IN THE NORTH...WHERE THE BLYR WILL LIKELY REMAIN
TOO DRY TO SUPPORT ANY CONVECTION.

EXTENSIVE CLOUD COVER AND LOW LVL MOISTURE WILL RESULT IN THE
WARMEST NIGHT/EARLY MORNING IN SOME TIME WITH LOWS RANGING FROM ARND
60F OVR THE N MTNS...TO ARND 70F ACROSS THE LOWER SUSQ VALLEY.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
REMNANTS OF UPPER LOW SHOULD TAKE UNTIL ARND MIDDAY TO CLEAR THE
SE COUNTIES...SO WILL CARRY A SLIGHT CHC OF A SHRA/TSRA DOWN THERE
UNTIL THAT TIME. RIDGING IN WAKE OF DEPARTING UPPER LOW SHOULD
BRING A PERIOD OF DRY CONDITIONS TO MOST OF CENTRAL PENN ON THURS
BEFORE COLD FRONT FROM THE GLAKES BRINGS ANOTHER THREAT OF
CONVECTION LATE IN THE DAY.

A RIBBON OF HIGHER PWATS BETWEEN 1.5 AND 1.75 INCHES AND SLIGHTLY
STEEPER MID-LEVEL LAPSE RATES SHOULD SUPPORT SCT SHRA/TSRA
DEVELOPING ACROSS THE NW MTNS THURSDAY AFTN AND SLIDING SE THRU
THE EVENING AND EARLY OVERNIGHT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
OVERVIEW...THE LATEST MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY
GOOD AGREEMENT IN THE LARGE SCALE MEAN FLOW PATTERN CONSISTING OF
A BUILDING/STRONG UPPER RIDGE OVER THE PLAINS/MS VLY WITH TROUGHS
JUST OFF THE WEST AND EAST COASTS. HOWEVER...THE PCPN PATTERN OVER
THE LOCAL AREA WILL BE MODULATED BY SHORTWV IMPULSES DIVING ESEWD
DOWN THE NERN/FRONT SIDE OF THE RIDGE WITHIN A NWLY FLOW ALOFT.
THEREFORE DESPITE ABOVE AVG CONFIDENCE IN THE MEAN PATTERN...THE
SMALLER SCALE EMBEDDED SYSTEM TIMING AND LOCAL QPF/SENSIBLE WX
IMPACT IS MORE UNCERTAIN. AS SUCH...THE FINAL DAY 3-7 GRIDS WERE
DERIVED USING A CONSENSUS BLEND IN AN EFFORT TO MITIGATE THE LOWER
CONFIDENCE IN THE SFC DETAILS AND TO BEHOLD REASONABLE CONTINUITY
THE FCST.

HIGHLIGHTS...PUSH OF ABNORMALLY DRY AIR WITH BELOW NORMAL PWS
BEHIND THE THUR NGT FROPA APPEARS DELAYED BY ABOUT 6 HRS ON THE
12Z CYCLE...SUGGESTING A LOW CHC FOR SHOWERS ALONG THE SRN TIER
ZONES EARLY FRI. OTHERWISE...A MODIFIED CANADIAN HIGH PRESSURE
SYSTEM WILL DOMINATE THE PATTERN THROUGH THE WEEKEND..BRINGING
RELATIVELY COOL NIGHTS WITH VALLEY FOG AND COMFORTABLE HUMIDITY
DURING THE DAY. EXPECT A MORE UNSETTLED AND INCREASINGLY HUMID
PATTERN TO EVOLVE THRU THE FIRST PART OF NEXT WEEK..AS THE FOCUS
SHIFTS TO UPPER-LEVEL DISTURBANCES CRESTING THE PLAINS RIDGE AND
DIVING ESEWD THRU THE GREAT LAKES TAKING AIM ON THE NE STATES.
MODELS SUGGEST THIS ENERGY MAY TRIGGER ONE OR MORE ORGANIZED TSTM
COMPLEXES AS THEY ROLL DOWN THE FRONT-SIDE OF THE RIDGE.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SHOWERS HAVE DIMINISHED GREATLY IN COVERAGE OVER THE LAST FEW
HOURS AND SHOULD GENERALLY BE DONE FOR THE NIGHT. IF ANY DO POP UP
THEY WILL BE OVER SRN PA...AT JST OR LNS TAF SITES. EXPECT AREAS OF
FOG/HAZE TO DEVELOP AS WELL...ALTHOUGH NOT AS THICK AS RECENT
NIGHTS WITH GREATER HGHT CLOUDS COVER KEEPING TEMPS FROM FALLING
OFF AS MUCH.

SLIGHTLY BETTER CHC FOR SHRA/TSRA STATEWIDE ON THURS AS A COLD
FRONT APPROACHES FROM THE GREAT LAKES. THIS FRONT SHOULD PASS
SOUTH OF THE REGION THURS NIGHT...WITH IMPROVING FLYING CONDS FOR
FRI INTO THIS WEEKEND.

OUTLOOK...

THU-THU NIGHT...MVFR POSSIBLE WITH SCT SHRA/TSRA.
FRI-MON...GENERALLY VFR.

&&

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

&&

$$
SYNOPSIS...FITZGERALD/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...FITZGERALD/EVANEGO
LONG TERM...STEINBUGL
AVIATION...GARTNER/EVANEGO










AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 1032 PM EDT FRI AUG 23 2013

.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION TONIGHT...TRIGGERING SHOWERS
AND THUNDERSTORMS BEFORE USHERING IN DRIER WEATHER FOR THE WEEKEND.
HIGH PRESSURE WILL BUILD BACK IN FOR THE FIRST PART OF THE
WEEK...BEGINNING A GRADUAL WARMING TREND. RETURNING SOUTHERLY FLOW
WILL GRADUALLY INCREASE MOISTURE ACROSS THE REGION...INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A SERIES OF
COLD FRONTS WILL MOVE THROUGH THE REGION LATE IN THE WEEK ELEVATING
RAIN CHANCES FURTHER.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 PM...STRONG CONVECTION OVER NE GA ATTM SHUD MOVE
SOUTHWEST OF THE CWFA BEFORE MIDNIGHT. LINGERING LIGHT SHRA OVER THE
UPSTATE...NE GA AND THE NW PIEDMONT SHOULD DISSIPATE MOVE OUT OF THE
AREA SHORTLY AFTER MIDNIGHT. FOG STILL EXPECTED TO FORM OVERNIGHT...
ESPECIALLY OVER WRN SECTIONS WHERE TSRA MOVED OVER. HOWEVER...THE
DEVELOPING NELY WINDS COULD HELP MIXING AND SCOUR FOG AS THEY MOVE
SW ACROSS THE CWFA. WITH WINDS NOT REACHING THE MTN VALLEYS...STILL
EXPECT PATCHY DENSE FOG THERE. STILL EXPECT LOW CLOUDS TO MOVE IN
WITH THE WINDS OVERNIGHT. THIS SHUD HELP LIMIT COOLING...BUT CURRENT
LOWS STILL LOOK GOOD.

AS OF 750 PM...CONVECTION CONTINUES TO SINK S AND WEST ACROSS THE
WRN UPSTATE. IT SHOULD MOVE INTO NE GA DURING THE EVENING...THEN
DIMINISH ALL AREAS BEFORE MIDNIGHT. THAT SAID...THERE IS SOME
CONVECTION DROPPING TOWARD THE NW PIEDMONT AND COULD AFFECT THE I-77
CORRIDOR LIKE THU NITE. HAVE UPDATED POP AND SKY WITH THESE TRENDS.
OTHERWISE...STILL EXPECT NELY WIND TO INCREASE OVERNIGHT WITH LOW
CLOUDS MOVING IN FROM THE NE. MTN VALLEYS THE EXCEPTION WHERE PATCHY
DENSE FOG EXPECTED ONCE AGAIN. LEFT SAT TRENDS THE SAME WITH SLOWLY
DIMINISHING CLOUDS FROM THE NE WITH GUSTY NELY MORNING WINDS. COULD
SEE SOME CONVECTION OVER THE MTNS...WRN UPSTATE AND NE GA WHERE
MOISTURE AND INSTABILITY WILL BE HIGHER AND DEEPER MOISTURE LINGERS.

AS OF 430 PM...AREA OF CONVECTION IS SHIFTING TO THE WRN CWFA AND
DYING OFF EAST OF I-77. HAVE UPDATED AFTERNOON AND EVENING POP TO
REFLECT THESE TRENDS. NOW HAVE HIGHEST POP FOLLOWING THE TRACK OF
THE CURRENT OUTFLOW BOUNDARY AND SPREADING ACROSS THE UPSTATE INTO
NE GA. ALSO HAVE HIGH POP SPREADING SW ACROSS THE NC MTNS AS WELL.
POP SIGNIFICANTLY REDUCED OVER THE I-77 CORRIDOR. SVR STORMS REMAIN
POSSIBLE AS THE STORMS MOVE INTO AN AREA WITH SIGNIFICANTLY HIGHER
DCAPE VALUES. TEMPS FELL SIGNIFICANTLY WITH THE LINE OF TSRA AND
HAVE FOLLOWED THESE TRENDS AS WELL...ALTHOUGH NOT AS DRAMATICALLY.

AS OF 230 PM EDT FRIDAY...A LINE OF SHOWERS AND THUNDERSTORMS HAS
DEVELOPED OVER THE WRN NC FOOTHILLS AND PIEDMONT. THE LINE IS BEING
FORCED BY LLVL SFC CONVERGENCE AND DIFFERENTIAL HEATING RESULTING
FROM THE APPROACH OF AN H5 SHORT WAVE WHICH THE RAP CURRENTLY HAS
LOCATED OVER NE TN AND SW VA. THE DEEP LAYER SHEAR ISN/T
STRONG...BUT THE AIRMASS AHEAD OF THE LINE IS QUITE UNSTABLE AND IT
ALREADY HAS A WELL ESTABLISHED REAR INFLOW JET PER THE TERMINAL
DOPPLER RADAR AT CHARLOTTE. THE NAM AND GFS BOTH STRENGTHEN SFC
CONVERGENCE AHEAD OF THE LINE. THEREFORE IT SHOULD CONTINUE TO MOVE
TO THE SOUTHEAST AND AT LEAST MAINTAIN ITSELF IF NOT GET STRONGER.
BUT IT SHOULD ALSO BUILD TO THE SOUTHWEST...OR NEW STORMS MAY
ORIGINATE OVER THE SC MTNS...AS THE LLVL WINDS BACK ACROSS MOST OF
THE UPSTATE AND EVEN INTO NE GA OVER THE NEXT COUPLE HOURS. AT THIS
RATE MOST LOCATIONS OVER THE FOOTHILLS AND PIEDMONT SHOULD GET INTO
THE ACT OVER THE NEXT 4 TO 6 HOURS AND POPS HAVE BEEN RAISED TO
LIKELY TO CATEGORICAL FOR THE REST OF THE DAY. DCAPE VALUES ARE HIGH
OVER THE UPSTATE...BUT DROP OFF RAPIDLY INTO NORTH CAROLINA. SO AS
THE LINE MOVE SOUTHWARD...IT/S TENDENCY TO PRODUCE STRONG OUTFLOW
SHOULD INCREASE.

STORMS SHOULD DIMINISH FROM NORTH TO SOUTH THIS EVENING. I THINK
THERE WILL ENOUGH CONVECTIVE DEBRIS AND MIXING EAST OF THE MTNS TO
PREVENT FOG FROM FORMING AGAIN. OVER THE MOUNTAINS WINDS ARE
EXPECTED TO DECOUPLE OVERNIGHT AS THE LLVL GRADIENT WINDS WILL BE
ORIENTED OUT OF THE NE...ORTHOGONAL TO THE HIGHER NC MTN CHAINS.
THEREFORE...THE MTN VALLEYS SHOULD SEE FOG AND STRATUS ONCE AGAIN.

COLD AIR DAMMING DEVELOPS FOR SATURDAY. THE MODELS STILL HAVE
1000-2000 SBCAPE VALUES OVER THE SOUTHERN ZONES. I/VE KEPT LOW END
CHANCE POPS ALONG THE UPPER SAVANNAH RIVER VALLEY AND OVER THE
SOUTHWEST AND CENTRAL NC MTNS. TYPICALLY IN THESE SITUATIONS MOST OF
THE DEVELOPMENT IS OVER THE SW MTNS AND ALONG THE EASTERN ESCARPMENT
OF THE BLUE RIDGE. CLOUDS MAY DISSIPATE IN THE DRIER AIR OVER THE
PIEDMONT AND ALONG THE TN LINE...WITH GENERALLY MOSTLY CLOUDY SKIES
EXPECTED ELSEWHERE.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 230 PM EDT FRIDAY...A STRONG UPPER HIGH WILL BE CENTERED OVER MO
ON SATURDAY NIGHT....WHILE A POSITIVELY TILTED UPPER TROUGH WILL BE
JUST OFF THE EAST COAST. THIS TROUGH MOVES FARTHER OFF THE EAST
COAST ON SUNDAY...WHILE THE UPPER RIDGE REMAINS CENTERED OVER MO. ON
MONDAY THE UPPER RIDGE RETROGRESSES INTO KS.

A COLD FRONT TO OUR SOUTH WILL DRIFT FARTHER SOUTH ACROSS FL
SATURDAY NIGHT AND SUNDAY...WHILE DRIER AIR AND HIGH PRESSURE SPREAD
ACROSS THE CAROLINAS AND GA FROM THE NE. MODEL TIME HEIGHTS SHOW A
THINNING...LINGERING LAYER OF MOISTURE AT AROUND 850 MB BEHIND THE
FRONT. WITH JUST A WEAK EASTERLY UPSLOPE FLOW DEVELOPING AS WINDS
VEER IN THE LOW LEVELS...ONLY VERY SMALL POPS WILL BE CARRIED SUNDAY
EVENING AND LATE MONDAY. TEMPERATURES WILL RUN BELOW NORMAL THROUGH
THE PERIOD...WITH A SLIGHT WARMING TREND ON MONDAY AS HEIGHTS RISE
ALOFT WITH THE PROGRESSION OF THE ATLANTIC TROUGH.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...OVERALL A MUCH DRIER PATTERN FOR THE
EXTENDED THAN WHAT WE HAVE SEEN IN THE PAST FEW WEEKS. AN UPPER
RIDGE WILL BE FIRMLY ENTRENCHED OVER THE CENTRAL PLAINS BY MONDAY
NIGHT WHILE A SURFACE RIDGE WILL SHIFT SOUTHEASTWARD TOWARDS THE
ATLANTIC TO TAKE ON BERMUDA HIGH CHARACTERISTICS. THIS WILL SET UP A
WEAK SOUTHEASTERLY FLOW REGIME AT THE SURFACE...AND BY WEDNESDAY A
HIGH IN THE NORTHEAST WILL ALLOW A WEAK WEDGE TO BUILD IN OVER THE
APPALACHIANS AND ADVECT IN MODERATELY DRIER AIR. ANY CONVECTION WILL
FOLLOW A DIURNAL PATTERN...AND THEN WILL BE LIMITED MAINLY TO AREAS
OF UPSLOPE FLOW. AN EXPANDING SURFACE HIGH OVER THE GREAT LAKES WILL
PUSH MULTIPLE FRONTAL BOUNDARIES SOUTHWARD THROUGH THE CWA BY THE
END OF THE WEEK...INCREASING RAIN CHANCES ONCE AGAIN. RISING HEIGHTS
DUE TO THE UPPER LEVEL RIDGE WILL ALLOW HIGH TEMPERATURES TO
MODERATE BACK TO NORMAL LEVELS...IN THE MID TO HIGH 80S...FOR MOST
OF NEXT WEEK.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...DO NOT EXPECT ANY ADDITIONAL CONVECTION THIS EVENING.
HOWEVER...COULD BE A REPEAT OF THU NITE WITH CONVECTION DROPPING
SOUTH EAST OF THE AIRFIELD. EITHER WAY...SHOULD BE MAINLY LIGHT NLY
WIND WITH MID AND HIGH CLOUD CIGS THRU THE EVENING. STRONGER NNE WIND
PICKS UP OVERNIGHT AS MVFR CLOUDS MOVE IN FROM THE NE. MVFR CIGS
CONTINUE THRU THE MORNING AS CLOUDS SLOWLY LIFT. COULD SEE SOME LOW
END GUSTS WITH MIXING AFTER DAYBREAK. NE WIND CONTINUES THRU THE
AFTERNOON AS CLOUDS LIFT AND SCATTER OUT.

ELSEWHERE...CONVECTION SHUD ONLY AFFECT KAND THIS EVENING WITH TSRA
GUSTY WINDS AND RESTRICTIONS ENDING BY 02Z. OTHERWISE...GENERALLY
NORTH WIND WITH MID AND HIGH CLOUDS THIS EVENING. STRONGER NELY
WINDS DEVELOP OVERNIGHT AS MVFR CLOUDS MOVE IN FROM THE NE. KAVL THE
EXCEPTION WITH LIGHT WINDS AND AT LEAST IFR FOG AND VSBY BY
DAYBREAK. CLOUDS SLOWLY LIFT THRU MVFR DURING THE MORNING WITH LOW
END GUSTS DEVELOPING WITH MIXING. KAVL WILL SEE MVFR BY MID MORNING
WITH LIGHT N WIND. CLOUDS LIFT AND SCATTER OUT THRU THE AFTERNOON
WITH NE WIND CONTINUING...EXCEPT SLY WIND AT KAVL. KAND HAS BEST CHC
TO SEE ANY CONVECTION DURING THE AFTERNOON...SO PROB30 THERE.

OUTLOOK...A DRIER PATTERN IS EXPECTED AS HIGH PRESSURE GRADUALLY
BUILDS IN FROM THE NORTH THRU THE WEEKEND.

CONFIDENCE TABLE...

            02-08Z        08-14Z        14-20Z        20-02Z
KCLT       HIGH  98%     HIGH  83%     HIGH  87%     HIGH 100%
KGSP       HIGH  87%     MED   71%     MED   77%     HIGH 100%
KAVL       HIGH 100%     HIGH  82%     HIGH  91%     HIGH 100%
KHKY       HIGH 100%     MED   77%     HIGH  94%     HIGH 100%
KGMU       HIGH 100%     HIGH  81%     MED   79%     HIGH 100%
KAND       HIGH  91%     HIGH  85%     MED   72%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...VISIN
NEAR TERM...MCAVOY/RWH
SHORT TERM...JAT
LONG TERM...VISIN
AVIATION...MCAVOY/RWH







AREA FORECAST DISCUSSION

NWS GREENVILLE-SPARTANBURG SC

 752 PM EDT FRI AUG 23 2013

.SYNOPSIS...
A COLD FRONT WILL MOVE INTO THE REGION TONIGHT...TRIGGERING SHOWERS
AND THUNDERSTORMS BEFORE USHERING IN DRIER WEATHER FOR THE WEEKEND.
HIGH PRESSURE WILL BUILD BACK IN FOR THE FIRST PART OF THE
WEEK...BEGINNING A GRADUAL WARMING TREND. RETURNING SOUTHERLY FLOW
WILL GRADUALLY INCREASE MOISTURE ACROSS THE REGION...INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS EACH AFTERNOON. A SERIES OF
COLD FRONTS WILL MOVE THROUGH THE REGION LATE IN THE WEEK ELEVATING
RAIN CHANCES FURTHER.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 750 PM...CONVECTION CONTINUES TO SINK S AND WEST ACROSS THE
WRN UPSTATE. IT SHOULD MOVE INTO NE GA DURING THE EVENING...THEN
DIMINISH ALL AREAS BEFORE MIDNIGHT. THAT SAID...THERE IS SOME
CONVECTION DROPPING TOWARD THE NW PIEDMONT AND COULD AFFECT THE I-77
CORRIDOR LIKE THU NITE. HAVE UPDATED POP AND SKY WITH THESE TRENDS.
OTHERWISE...STILL EXPECT NELY WIND TO INCREASE OVERNIGHT WITH LOW
CLOUDS MOVING IN FROM THE NE. MTN VALLEYS THE EXCEPTION WHERE PATCHY
DENSE FOG EXPECTED ONCE AGAIN. LEFT SAT TRENDS THE SAME WITH SLOWLY
DIMINISHING CLOUDS FROM THE NE WITH GUSTY NELY MORNING WINDS. COULD
SEE SOME CONVECTION OVER THE MTNS...WRN UPSTATE AND NE GA WHERE
MOISTURE AND INSTABILITY WILL BE HIGHER AND DEEPER MOISTURE LINGERS.

AS OF 430 PM...AREA OF CONVECTION IS SHIFTING TO THE WRN CWFA AND
DYING OFF EAST OF I-77. HAVE UPDATED AFTERNOON AND EVENING POP TO
REFLECT THESE TRENDS. NOW HAVE HIGHEST POP FOLLOWING THE TRACK OF
THE CURRENT OUTFLOW BOUNDARY AND SPREADING ACROSS THE UPSTATE INTO
NE GA. ALSO HAVE HIGH POP SPREADING SW ACROSS THE NC MTNS AS WELL.
POP SIGNIFICANTLY REDUCED OVER THE I-77 CORRIDOR. SVR STORMS REMAIN
POSSIBLE AS THE STORMS MOVE INTO AN AREA WITH SIGNIFICANTLY HIGHER
DCAPE VALUES. TEMPS FELL SIGNIFICANTLY WITH THE LINE OF TSRA AND
HAVE FOLLOWED THESE TRENDS AS WELL...ALTHOUGH NOT AS DRAMATICALLY.

AS OF 230 PM EDT FRIDAY...A LINE OF SHOWERS AND THUNDERSTORMS HAS
DEVELOPED OVER THE WRN NC FOOTHILLS AND PIEDMONT. THE LINE IS BEING
FORCED BY LLVL SFC CONVERGENCE AND DIFFERENTIAL HEATING RESULTING
FROM THE APPROACH OF AN H5 SHORT WAVE WHICH THE RAP CURRENTLY HAS
LOCATED OVER NE TN AND SW VA. THE DEEP LAYER SHEAR ISN/T
STRONG...BUT THE AIRMASS AHEAD OF THE LINE IS QUITE UNSTABLE AND IT
ALREADY HAS A WELL ESTABLISHED REAR INFLOW JET PER THE TERMINAL
DOPPLER RADAR AT CHARLOTTE. THE NAM AND GFS BOTH STRENGTHEN SFC
CONVERGENCE AHEAD OF THE LINE. THEREFORE IT SHOULD CONTINUE TO MOVE
TO THE SOUTHEAST AND AT LEAST MAINTAIN ITSELF IF NOT GET STRONGER.
BUT IT SHOULD ALSO BUILD TO THE SOUTHWEST...OR NEW STORMS MAY
ORIGINATE OVER THE SC MTNS...AS THE LLVL WINDS BACK ACROSS MOST OF
THE UPSTATE AND EVEN INTO NE GA OVER THE NEXT COUPLE HOURS. AT THIS
RATE MOST LOCATIONS OVER THE FOOTHILLS AND PIEDMONT SHOULD GET INTO
THE ACT OVER THE NEXT 4 TO 6 HOURS AND POPS HAVE BEEN RAISED TO
LIKELY TO CATEGORICAL FOR THE REST OF THE DAY. DCAPE VALUES ARE HIGH
OVER THE UPSTATE...BUT DROP OFF RAPIDLY INTO NORTH CAROLINA. SO AS
THE LINE MOVE SOUTHWARD...IT/S TENDENCY TO PRODUCE STRONG OUTFLOW
SHOULD INCREASE.

STORMS SHOULD DIMINISH FROM NORTH TO SOUTH THIS EVENING. I THINK
THERE WILL ENOUGH CONVECTIVE DEBRIS AND MIXING EAST OF THE MTNS TO
PREVENT FOG FROM FORMING AGAIN. OVER THE MOUNTAINS WINDS ARE
EXPECTED TO DECOUPLE OVERNIGHT AS THE LLVL GRADIENT WINDS WILL BE
ORIENTED OUT OF THE NE...ORTHOGONAL TO THE HIGHER NC MTN CHAINS.
THEREFORE...THE MTN VALLEYS SHOULD SEE FOG AND STRATUS ONCE AGAIN.

COLD AIR DAMMING DEVELOPS FOR SATURDAY. THE MODELS STILL HAVE
1000-2000 SBCAPE VALUES OVER THE SOUTHERN ZONES. I/VE KEPT LOW END
CHANCE POPS ALONG THE UPPER SAVANNAH RIVER VALLEY AND OVER THE
SOUTHWEST AND CENTRAL NC MTNS. TYPICALLY IN THESE SITUATIONS MOST OF
THE DEVELOPMENT IS OVER THE SW MTNS AND ALONG THE EASTERN ESCARPMENT
OF THE BLUE RIDGE. CLOUDS MAY DISSIPATE IN THE DRIER AIR OVER THE
PIEDMONT AND ALONG THE TN LINE...WITH GENERALLY MOSTLY CLOUDY SKIES
EXPECTED ELSEWHERE.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 230 PM EDT FRIDAY...A STRONG UPPER HIGH WILL BE CENTERED OVER MO
ON SATURDAY NIGHT....WHILE A POSITIVELY TILTED UPPER TROUGH WILL BE
JUST OFF THE EAST COAST. THIS TROUGH MOVES FARTHER OFF THE EAST
COAST ON SUNDAY...WHILE THE UPPER RIDGE REMAINS CENTERED OVER MO. ON
MONDAY THE UPPER RIDGE RETROGRESSES INTO KS.

A COLD FRONT TO OUR SOUTH WILL DRIFT FARTHER SOUTH ACROSS FL
SATURDAY NIGHT AND SUNDAY...WHILE DRIER AIR AND HIGH PRESSURE SPREAD
ACROSS THE CAROLINAS AND GA FROM THE NE. MODEL TIME HEIGHTS SHOW A
THINNING...LINGERING LAYER OF MOISTURE AT AROUND 850 MB BEHIND THE
FRONT. WITH JUST A WEAK EASTERLY UPSLOPE FLOW DEVELOPING AS WINDS
VEER IN THE LOW LEVELS...ONLY VERY SMALL POPS WILL BE CARRIED SUNDAY
EVENING AND LATE MONDAY. TEMPERATURES WILL RUN BELOW NORMAL THROUGH
THE PERIOD...WITH A SLIGHT WARMING TREND ON MONDAY AS HEIGHTS RISE
ALOFT WITH THE PROGRESSION OF THE ATLANTIC TROUGH.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...OVERALL A MUCH DRIER PATTERN FOR THE
EXTENDED THAN WHAT WE HAVE SEEN IN THE PAST FEW WEEKS. AN UPPER
RIDGE WILL BE FIRMLY ENTRENCHED OVER THE CENTRAL PLAINS BY MONDAY
NIGHT WHILE A SURFACE RIDGE WILL SHIFT SOUTHEASTWARD TOWARDS THE
ATLANTIC TO TAKE ON BERMUDA HIGH CHARACTERISTICS. THIS WILL SET UP A
WEAK SOUTHEASTERLY FLOW REGIME AT THE SURFACE...AND BY WEDNESDAY A
HIGH IN THE NORTHEAST WILL ALLOW A WEAK WEDGE TO BUILD IN OVER THE
APPALACHIANS AND ADVECT IN MODERATELY DRIER AIR. ANY CONVECTION WILL
FOLLOW A DIURNAL PATTERN...AND THEN WILL BE LIMITED MAINLY TO AREAS
OF UPSLOPE FLOW. AN EXPANDING SURFACE HIGH OVER THE GREAT LAKES WILL
PUSH MULTIPLE FRONTAL BOUNDARIES SOUTHWARD THROUGH THE CWA BY THE
END OF THE WEEK...INCREASING RAIN CHANCES ONCE AGAIN. RISING HEIGHTS
DUE TO THE UPPER LEVEL RIDGE WILL ALLOW HIGH TEMPERATURES TO
MODERATE BACK TO NORMAL LEVELS...IN THE MID TO HIGH 80S...FOR MOST
OF NEXT WEEK.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...DO NOT EXPECT ANY ADDITIONAL CONVECTION THIS EVENING.
HOWEVER...COULD BE A REPEAT OF THU NITE WITH CONVECTION DROPPING
SOUTH EAST OF THE AIRFIELD. EITHER WAY...SHOULD BE MAINLY LIGHT NLY
WIND WITH MID AND HIGH CLOUD CIGS THRU THE EVENING. STRONGER NNE WIND
PICKS UP OVERNIGHT AS MVFR CLOUDS MOVE IN FROM THE NE. MVFR CIGS
CONTINUE THRU THE MORNING AS CLOUDS SLOWLY LIFT. COULD SEE SOME LOW
END GUSTS WITH MIXING AFTER DAYBREAK. NE WIND CONTINUES THRU THE
AFTERNOON AS CLOUDS LIFT AND SCATTER OUT.

ELSEWHERE...CONVECTION SHUD ONLY AFFECT KAND THIS EVENING WITH TSRA
GUSTY WINDS AND RESTRICTIONS ENDING BY 02Z. OTHERWISE...GENERALLY
NORTH WIND WITH MID AND HIGH CLOUDS THIS EVENING. STRONGER NELY
WINDS DEVELOP OVERNIGHT AS MVFR CLOUDS MOVE IN FROM THE NE. KAVL THE
EXCEPTION WITH LIGHT WINDS AND AT LEAST IFR FOG AND VSBY BY
DAYBREAK. CLOUDS SLOWLY LIFT THRU MVFR DURING THE MORNING WITH LOW
END GUSTS DEVELOPING WITH MIXING. KAVL WILL SEE MVFR BY MID MORNING
WITH LIGHT N WIND. CLOUDS LIFT AND SCATTER OUT THRU THE AFTERNOON
WITH NE WIND CONTINUING...EXCEPT SLY WIND AT KAVL. KAND HAS BEST CHC
TO SEE ANY CONVECTION DURING THE AFTERNOON...SO PROB30 THERE.

OUTLOOK...A DRIER PATTERN IS EXPECTED AS HIGH PRESSURE GRADUALLY
BUILDS IN FROM THE NORTH THRU THE WEEKEND.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH 100%     HIGH  87%     MED   75%     HIGH 100%
KGSP       HIGH  97%     MED   74%     MED   73%     HIGH  98%
KAVL       HIGH 100%     HIGH  89%     HIGH  81%     HIGH 100%
KHKY       HIGH 100%     HIGH  87%     HIGH  85%     HIGH 100%
KGMU       HIGH 100%     HIGH  93%     MED   69%     HIGH 100%
KAND       HIGH 100%     HIGH  88%     MED   61%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...VISIN
NEAR TERM...MCAVOY/RWH
SHORT TERM...JAT
LONG TERM...VISIN
AVIATION...MCAVOY/RWH







AREA FORECAST DISCUSSION

NWS SPOKANE WA

 1033 AM PDT Thu Aug 22 2013

.SYNOPSIS...
Warm and dry weather will continue through Thursday. Chances for
showers and thunderstorms will increase Thursday night into Friday
as a moist upper level disturbance tracks across eastern
Washington and the Idaho Panhandle. Warm weather with the threat
for thunderstorms will persist through the weekend into early next
week as a moist southwest flow pattern remains over the region.


&&

.DISCUSSION...
Upgraded fire weather products to red flag warnings with an update
earlier this morning and added sprinkles near the Lewiston
vicinity and some points northeast based on Radar and HRRR model
runs this morning. No other significant changes made as as the
most impressive portion of the forecast remains overnight and into
Friday as an upper level low pushes thunderstorms from south to
north through the forecast area in varying intensity. /Pelatti

&&

.AVIATION...
18Z TAFS: The only possible MVFR condition will be from wildfire
smoke around KEAT, but the threat is not significant enough at
this time to include in the TAF forecast. Mid to high level clouds
will continue to stream through the next 12 hrs or so. After 6Z
thunderstorms will start to make progress in the far south and
continue to move north and impact the aviation area into Friday.
/Pelatti

&&

.PRELIMINARY POINT TEMPS/POPS...
Spokane        90  63  81  58  83  60 /   0  30  50  10  20  20
Coeur d`Alene  89  57  79  54  83  57 /   0  30  50  10  20  20
Pullman        90  57  80  51  83  52 /  10  40  50  10  20  20
Lewiston       95  66  87  61  90  62 /  10  30  50  10  10  20
Colville       92  55  85  52  86  54 /   0  20  50  20  20  10
Sandpoint      87  53  77  48  83  51 /   0  20  50  30  20  20
Kellogg        88  56  77  54  84  56 /  10  30  50  20  20  20
Moses Lake     93  65  87  58  84  59 /   0  30  40  10  20  10
Wenatchee      91  65  86  62  83  63 /   0  20  30   0  20  10
Omak           92  61  87  58  85  60 /   0  20  40  10  20  10

&&

.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Red Flag Warning from 11 PM this evening to 2 PM PDT Friday for
     Northern and Central Idaho Panhandle (Zone 101).

WA...Red Flag Warning from 11 PM this evening to 2 PM PDT Friday for
     East Washington Northeast (Zone 686)-East Washington
     Northern Columbia Basin (Zone 673)-East Washington Okanogan
     Highlands (Zone 687)-East Washington Palouse and Spokane
     Area (Zone 674).

&&

$$








FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE



 .SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 243 PM CDT THU AUG 22 2013

LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SLOWLY
WEAKENING MCS MOVING OVER SOUTHERN LAKE MICHIGAN EARLY THIS
AFTERNOON.  BACK EDGE OF THE CLOUD SHIELD ASSOCIATED WITH THIS MCS
IS MOVING SE OVER CENTRAL AND NORTHEAST WISCONSIN.  DEWPOINTS ACROSS
NORTHERN WISCONSIN HAVE MIXED OUT INTO THE MIDDLE 40S...WHILE THE
DRIER AIR IS SLOWLY MOVING INTO EAST-CENTRAL WISCONSIN WHERE
READINGS ARE STILL IN THE UPPER 50S.  PLENTY OF CLEAR SKIES UPSTREAM
OVER THE NORTHERN PLAINS AND SOUTH-CENTRAL CANADA WHERE SURFACE HIGH
PRESSURE IS SHIFTING TO THE SOUTHEAST.  AS HIGH PRESSURE MOVES
TOWARDS THE REGION...FOG POTENTIAL TONIGHT AND TEMPS ARE THE MAIN
FORECAST CONCERNS.

TONIGHT...SURFACE HIGH PRESSURE WILL MOVE SOUTHEAST ACROSS THE
NORTHERN GREAT LAKES.  AS THIS OCCURS...SKIES WILL BECOME CLEAR AND
WINDS WILL TURN LIGHT AND VARIABLE...SETTING UP GOOD RADIATIONAL
COOLING CONDITIONS.  DEWPOINTS HAVE FALLEN INTO THE MIDDLE 40S
ACROSS NORTHERN WISCONSIN THIS AFTERNOON...WHILE THEY REMAIN IN THE
MIDDLE 50S TO LOWER 60S OVER CENTRAL AND EAST-CENTRAL WISCONSIN.
SOME MIXING OUT IS STILL EXPECTED...LOW TEMPS ARE EXPECTED TO
FALL NEAR OR BELOW THESE READINGS ACROSS MOST LOCATIONS.  WITH THE
RECENT RAINFALL...WILL ADD PATCHY FOG TO THE FORECAST.  LOWS NEAR 40
DEGREES AT THE COLD SPOTS OF N-C WISCONSIN AND THE MID 50S SOUTH.

FRIDAY...HIGH PRESSURE WILL REMAIN ACROSS THE AREA.  OUTSIDE OF SCT
DIURNAL CU...SHOULD SEE PLENTY OF SUN AND LOW RELATIVE HUMIDITY.
HIGHS MOSTLY IN THE UPPER 70S TO LOWER 80S...LOCALLY COOLER NEAR
LAKE MICHIGAN.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 243 PM CDT THU AUG 22 2013

CONCERNS THIS PERIOD WILL BE HEAT...WITH TEMPS EXPECTED TO RUN
WELL ABOVE NORMAL AND HUMIDITY LEVELS INCREASING THROUGH THE
PERIOD. MEDIUM RANGE MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT
THROUGH THE EXTENDED WITH THE LARGE SCALE. STRONG RIDGE ANCHORED
BY 596 CENTER EXPECTED TO BE FOUND OVER THE CENTRAL PORTION OF THE
U.S. DIFFERENCES OCCUR WITH SMALL SCALE FEATURES...S/W`S MOVING
THROUGH SW FLOW OVER RIDGE AND WITH EXPECTED LOCATION OF SURFACE
BOUNDARY. OVERALL 850 TEMPS TO RUN WELL ABOVE NORMAL BY AT LEAST
TWO STANDARD DEVIATIONS FOR THIS TIME OF YEAR. LOCAL TEMPERATURE
TOOLS WOULD SUGGEST TEMPS INTO THE 90`S MONDAY ONWARD.

FOR MUCH OF THIS FORECAST USED A BLEND OF GFS/ECMWF...THOUGH WENT
MORE WITH EC TUE ONWARD AS GFS APPEARS TO BE TOO STRONG WITH
SURFACE FEATURES. WARM MID LEVEL TEMPS WOULD ALSO SUGGEST
ATMOSPHERE WOULD BE CAPPED FOR CONVECTION THOUGH SFC FRONT
EXPECTED TO MOVE NORTH THROUGH REGION SAT NIGHT/SUN. BOTH GFS AND
ECMWF DROP FRONT BACK SOUTH INTO NORTHERN WI WED/THU BEFORE
LIFTING IT BACK NORTH BEYOND THIS FORECAST PERIOD. WILL ONLY GO
WITH SLIGHT CHANCE/CHANCE POPS THROUGH PERIOD. OVERALL BEST CHANCE
FOR STRONG TO SEVERE STORMS...IF ANY..WOULD BE WED/THU TIME FRAME
AS SHEER INCREASES AS JET DROPS SOUTH.
&&

.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1218 PM CDT THU AUG 22 2013

SHOWERS AND THUNDERSTORMS EXPECTED TO REMAIN SOUTH OF
THE TAF SITES THIS AFTERNOON. AS STORMS OVER SOUTHERN WISCONSIN EXIT
ACROSS SOUTHERN LAKE MICHIGAN...WILL SEE DECREASING CLOUDS DURING
THE AFTERNOON.  HIGH PRESSURE WILL SETTLE ACROSS THE REGION
TONIGHT.  WITH CLEAR SKIES AND LIGHT WINDS...PATCHY GROUND FOG WILL
DEVELOP LATE TONIGHT AND EARLY FRIDAY MORNING.  THE FOG WILL BE MORE
DENSE/WIDESPREAD OVER NORTH-CENTRAL WISCONSIN COMPARED TO ELSEWHERE.
ONCE THE FOG BURNS OFF...VFR CONDITIONS TO RETURN.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC







AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 1100 PM CDT WED AUG 21 2013

.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 323 PM CDT WED AUG 21 2013

MAIN FOCUS WILL BE ON THE FRONTAL PASSAGE TONIGHT AND THE
ASSOCIATED RAIN CHANCES.

COLD FRONT EXTENDS FROM NORTHERN WISCONSIN INTO NORTHEAST NEBRASKA
AT MID AFTERNOON. REGIONAL RADARS SHOW CONVECTIVE ACTIVITY ALONG
THE FRONT FROM NORTHERN WISCONSIN ACROSS MINNESOTA.

WATER VAPOR SATELLITE SHOWS THE MAIN SHORT WAVE TROUGH IS ALONG
THE CANADIAN BORDER MOVING INTO ONTARIO WITH A SECONDARY WAVE OVER
CENTRAL MINNESOTA. THE BEST PV ADVECTION IN THE 500-300 MB LAYER
WILL STAY TO THE NORTH OF THE AREA TONIGHT BUT THE EXPECTATION IS
THAT THE WAVE OVER MINNESOTA WILL PROVIDE JUST ENOUGH FORCING TO
HELP MAINTAIN THE CONVECTION ALONG THE FRONT AS IT COMES THROUGH.
ML CAPES AHEAD OF THE FRONT CURRENTLY ARE AROUND 3000 J/KG AND
WHILE THESE WILL DECREASE THROUGH THE EVENING WITH THE LOSS OF
HEATING...THE 21.18Z NAM INDICATES THESE WILL STAY AT OR ABOVE
1500 J/KG THROUGH THE EVENING AHEAD OF THE FRONT. THE BEST 0-6KM
SHEAR WILL REMAIN NORTH OF THE AREA CLOSER TO THE MAIN SHORT WAVE
TROUGH. HOWEVER...THE 0-3KM SHEAR WILL BE AROUND 30 KNOTS AND WILL
BE MORE THAN SUFFICIENT TO SUPPORT SOME SEVERE STORMS THROUGH THE
EVENING. LARGE HAIL AND DAMAGING WINDS STILL LOOK TO BE THE MAIN
THREATS. WILL BE INTERESTING TO SEE HOW THE CURRENT ACTIVITY
SOUTH OF THE TWIN CITIES EVOLVES THROUGH THE REMAINDER OF THE
AFTERNOON. THE 21.18Z RAP BUFKIT SOUNDINGS SUGGEST THE CAP IN
PLACE BETWEEN 750 AND 800 MB AT KRST WILL HOLD TIGHT UNTIL THE
FRONT MOVES THROUGH. IF THIS HAPPENS...THE ACTIVITY TO THE WEST
SHOULD DIMINISH AS IT MOVES IN AND THIS IS WHAT SEVERAL OF THE
SHORT RANGE MESO MODELS SUGGESTS. BASED ON THIS...HAVE TRIMMED
BACK THE RAIN CHANCES HEADING THROUGH THE EVENING ACROSS THE
WESTERN SECTIONS OF THE FORECAST AREA. FARTHER EAST...THE CAP IS
WEAKER AND IS EXPECTED TO ERODE AS THE FRONT MOVES IN...SO HAVE
MAINTAINED THE 60 TO 80 PERCENT CHANCES EAST OF THE MISSISSIPPI
RIVER.

ALL THE MODELS ALSO SUGGEST THE FRONT AND CONVECTION WILL MOVE
THROUGH PRETTY QUICK THIS EVENING TO THE POINT THAT MOST IF NOT
ALL OF THE FORECAST AREA SHOULD BE DRY BY 06Z. THUS SPED UP THE
FORECAST TO REFLECT THIS FASTER TIMING WITH JUST SOME 20 TO 40
PERCENT RAIN CHANCES ACROSS THE SOUTH FOR AFTER MIDNIGHT. HAVE
HELD ON TO SOME SMALL RAIN CHANCES ACROSS THE SOUTH FOR THURSDAY
MORNING. ALL THE MODELS INDICATE A CONVECTIVE COMPLEX WILL DEVELOP
ACROSS NEBRASKA THIS EVENING AND THEN MOVE EAST ALONG THE FRONT
TOWARD THE AREA OVERNIGHT WITH SOME SUGGESTIONS THAT THE NORTHERN
PART OF THE COMPLEX COULD SLIDE ACROSS THE SOUTHERN PARTS OF THE
AREA. OTHERWISE FOR THURSDAY...HIGH PRESSURE WILL MOVE IN FROM THE
NORTH WITH MUCH DRIER AIR SPREADING IN. NAM BUFKIT SOUNDING ACROSS
THE NORTHERN SECTIONS SHOW GOOD SUBSIDENCE OCCURRING AND WITH LOTS
OF DRY ALOFT TO MIX DOWN...DEW POINTS ARE EXPECTED TO DROP INTO
THE 40S FOR THE AFTERNOON. THIS HIGH WILL REMAIN THE DOMINANT
FEATURE FOR THE REMAINDER OF THE SHORT TERM HELPING TO KEEP
TEMPERATURES CLOSER TO NORMAL THROUGH FRIDAY WITH HIGHS IN THE
UPPER 70S TO LOWER 80S.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 323 PM CDT WED AUG 21 2013

CONSIDERABLE UNCERTAINTY IN THE EXTENDED IN REGARDS TO THE RAIN
CHANCES. THE UPPER LEVEL RIDGE WILL BE ANCHORED OVER THE CENTRAL
PART OF THE COUNTRY WITH ALL THE MODELS SHOWING SHORT WAVE TROUGHS
EXPECTED TO RIDE UP THE BACK SIDE AND OVER THE TOP OF THE RIDGE.
AT THE SURFACE...THE EXPECTATION IS THAT A WEAK SURFACE BOUNDARY
WILL APPROACH FROM THE WEST SATURDAY BUT STALL OUT AND BECOME
NEARLY STATIONARY BEFORE IT REACHES THE AREA. IT SHOULD THEN
WAFFLE NORTH/SOUTH AS SHORT WAVE TROUGHS MOVE AROUND THE RIDGE AND
CAUSE ROUNDS OF CONVECTION TO FORM. THE UNCERTAINTY COMES IN WHERE
THESE COMPLEXES WILL BE AND WHETHER THEY WILL IMPACT THE NORTHERN
PARTS OF THE FORECAST AREA OR NOT. AFTER THE INITIAL SHORT WAVE
TROUGH GOES BY SATURDAY WILL GENERALLY LIMIT THE RAIN CHANCES TO
THE I94 CORRIDOR FOR THE REMAINDER OF THE EXTENDED PERIOD AS THIS
AREA WILL BE CLOSEST TO THE FRONT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1100 PM CDT WED AUG 21 2013

A COLD FRONT WILL CONTINUE TO SLIDE SLOWLY SOUTHWARD
TONIGHT...GRADUALLY LAYING UP WEST TO EAST ACROSS CENTRAL IA.
MODELS POINTED TO A STORM COMPLEX DEVELOPING OVER NEB...AND RADAR
INDICATES IT HAS...AND IS MOVING EAST. LATEST HRRR/NAM12 ARE A LOT
MORE NORTH THAN MODEL RUNS OF THE PAST COUPLE DAYS. WHILE THE BULK
OF THE COMPLEX SHOULD STAY SOUTH...THERE COULD BE SOME SCATTERED
-SHRA THAT PASS ACROSS KRST/KLSE BETWEEN 12-15Z. WILL ADD A VCSH TO
ACCOUNT FOR THIS POTENTIAL. BELIEVE CIGS WILL STAY VFR.

MEANWHILE...MOIST SFC AIR LAGS BEHIND THE FRONT A BIT...WITH LATEST
RAP13 SUGGESTING DRIER AIR NOT WORKING INTO KRST/KLSE UNTIL AFTER
12Z. LIGHT SFC AND NEAR SFC WINDS FAVOR FOG FORMATION...ESPECIALLY
IN THE RIVER VALLEYS. RAIN OVER THE PAST FEW HOURS HELPS TOO. THINK
THIS WOULD BE A 1/4SM TYPE EVENT FOR KLSE...EXCEPT FOR THE
INCREASING CLOUDS/RAIN POTENTIAL FROM THE WEST. AS LONG AS THESE
ROLL IN AND STAY OVER KLSE...4-P6SM WOULD BE MORE LIKELY. SAME FOR
KRST. ALSO...THIS COULD PLAY OUT WITH FOG DEVELOPING EARLY...THEN
QUICKLY LIFTING INTO A SCT-BKN LOW STRATUS LAYER AS THE HIGH CLOUDS
MOVE IN. TRENDS WILL HAVE TO BE MONITORED CLOSELY OVERNIGHT.

HIGH PRESSURE BUILDS IN FROM SOUTHERN CANADA THU...AND PRESSURE
GRADIENT SLACKENS. COULD SEE SOME GUSTS IN THE MORNING...BUT LOW
LEVEL WINDS WEAKEN IN THE AFTERNOON. EXPECT VFR CONDITIONS WITH SOME
SCT-BKN HIGH CLOUDS. WITH HIGH PRESSURE WORKING OVER WI THU
NIGHT...FOG HAS TO BE CONSIDERED. AGAIN...CONDITIONS WOULD SEEM TO
LEAN TOWARD VALLEY FOG - IF IT DEVELOPS. AT THIS TIME...NAM BUFKIT
SOUNDINGS SUGGEST IT WOULD BE TOO BREEZY OFF THE SFC FOR A FG IMPACT
AT KLSE. THIS IS SUBJECT TO CHANGE OF COURSE. BR/FG POTENTIAL WILL
CONTINUE TO EVALUATED.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

SHORT TERM...04
LONG TERM....04
AVIATION.....RIECK














AREA FORECAST DISCUSSION

NWS MIAMI FL

 418 AM EDT SAT AUG 24 2013

.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL IMPACT SOUTH FLORIDA MAINLY FROM
TONIGHT THROUGH EARLY IN THE WEEK...LEADING TO A GRADUAL INCREASE IN
RAIN CHANCES THROUGH THE PERIOD. HIGH PRESSURE BUILDS BACK INTO THE
REGION EARLY TO MIDDLE PART OF THE NEXT WEEK.

&&

.SHORT TERM /TODAY THROUGH SUNDAY NIGHT/...
SYNOPTIC PATTERN THIS WEEKEND WILL BE DOMINATED BY H5 TROUGH OVER EASTERN
UNITED STATES WITH ITS AXIS AND ASSOCIATED SHORT WAVE...THOUGH DIFFUSE
BUT SHOWN IN VARYING DEGREES BY BOTH GLOBAL AND MESOSCALE MODELS...REACHING
VICINITY OF SOUTH FLORIDA PARTICULARLY BY SUNDAY WITH ITS INFLUENCE
ACROSS THE AREA INCREASING BEGINNING TODAY. ALONG WITH THIS FEATURE...A
LOW-LEVEL BOUNDARY/DECAYING COLD FRONT WILL SPREAD INTO CENTRAL FLORIDA
TODAY AND COULD REACH SOUTH FLORIDA SUNDAY ALTHOUGH IT IS MOST LIKELY
TO WASH OUT BEFORE THEN BUT ITS LINGERING LEFT OVER WILL HELP ENHANCE
CHANCES OF RAIN. WINDS COULD TURN NORTHEASTERLY SUNDAY WITH THIS SOLUTION...AS
NAM AS WELL AS GFS SUGGEST THE BOUNDARY WILL EITHER PASS THROUGH MOST
OF THE CWA SOMETIME BETWEEN LATE SUNDAY AND MONDAY OR SIMPLY THE WIND
WILL SHIFT FROM THE NORTHEAST AS HIGH BUILDS NORTH OF THE AREA BEHIND
DIFFUSING BOUNDARY.

FOR TODAY...HIGH RESOLUTION LOCAL MODELS ALONG WITH HRRR INDICATE PATTERN
OF LATE MORNING AND EARLY AFTERNOON EAST COAST SHOWERS AND STORMS TRANSITIONING
TO INTERIOR AND WEST COAST AGAIN DURING THE AFTERNOON AND EVENING. STORM
MOTION VECTOR FAVORS INTERIOR AND WEST COAST BUT IS WEAK ENOUGH THAT
SOME ACTIVITY MIGHT LINGER ACROSS EAST COAST ALSO INTO THE AFTERNOON
AND EVENING. FOR SUNDAY CONVERGENCE IN THE VICINITY OF THE AFOREMENTIONED
SURFACE BOUNDARY COULD ENHANCE SHOWERS AND THUNDERSTORMS...BUT EVEN
IF BOUNDARY REMAINS NORTH OF CWA...SCATTERED TO NUMEROUS SHOWERS AND
STORMS CAN BE EXPECTED WITH STORM MOTION VECTORS SUGGESTING ABOUT EQUAL
CHANCES EVERYWHERE. WE ARE BASICALLY TALKING ABOUT AN ENHANCED DIURNAL
CYCLE WITH LINGERING ACTIVITY POSSIBLY EXTENDING INTO SUNDAY NIGHT IN
THE PRESENCE OF UPPER LEVEL S/W.

TEMPERATURES WILL CONTINUE TO BE SLIGHTLY ABOVE NORMAL...PARTICULARLY
DURING THE OVERNIGHTS.

ONSHORE FLOW WILL CONTINUE THROUGH THE WEEKEND ALBEIT WEAKER...PROLONGING
A SLIGHT RISK OF RIP CURRENTS ON ATLANTIC BEACHES. HOWEVER...THIS
THREAT SHOULD BE GRADUALLY DIMINISHING INTO THE WEEKEND.

.LONG TERM /MONDAY THROUGH FRIDAY/...
THE PREVIOUS DISCUSSED SURFACE BOUNDARY AND UPPER S/W WILL FURTHER
WEAKEN THROUGH THE FIRST HALF OF THE UPCOMING WEEK BUT NOT WITHOUT
RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND STORMS AGAIN ON MONDAY.
HOWEVER BY THE MIDDLE TO LATTER PART OF THE WEEK AN UPPER LEVEL
TROUGH OFF THE EAST COAST OF THE US WILL RETROGRADE IN
ASSOCIATION WITH HIGH AMPLITUDE WAVE PATTERN. GFS IS MORE
AGGRESSIVE WITH THIS THAN ECMWF BUT THE BOTTOM LINE IS THE AREA
WILL BE BETWEEN A STRONG HIGH PRESSURE RIDGE ACROSS THE MIDDLE OF
THE COUNTRY AND THE TROUGH OF LOW PRESSURE OFF THE EAST COAST OF THE
US. THIS IS ALSO CONSISTENT WITH THE ENSEMBLE FORECASTS. AT LOW
LEVELS AREA WILL BE UNDER THE INFLUENCE OF WEAK RIDGE OF HIGH
PRESSURE JUST TO THE NORTH POSSIBLY PUSHING SOUTH ACROSS THE AREA
BY LATE IN THE WEEK. ALONG WITH THIS MOISTURE LEVELS WILL BE
RUNNING ABOVE NORMAL EARLY IN THE WEEK, AROUND NORMAL MIDDLE TO
LATTER PART OF THE WEEK AND PERHAPS SLIGHTLY ABOVE NORMAL BY LATE IN
THE WEEK.

BOTTOM LINE...AFTER THE START OF THE WEEK ON MONDAY AREA WILL BE
UNDER A WEAK STEERING FLOW ENVIRONMENT WITH ABOUT EQUAL CHANCES
OF SCATTERED SHOWERS AND THUNDERSTORMS EVERYWHERE THROUGH THE PERIOD
ALONG WITH TYPICAL DIURNAL CYCLE AND TEMPERATURES NEAR NORMAL.


&&

.MARINE...
OUTSIDE A BRIEF PERIOD OF WINDS OF AROUND 15 KNOTS OFFSHORE THE
SOUTHWEST FLORIDA COAST SUNDAY...WINDS AND WAVES WILL REMAIN BELOW
10 TO 15 KNOTS AND 2 TO 4 FEET RESPECTIVELY THROUGH THE FORECAST
PERIOD SO NO HIGHLIGHTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  90  78  87  76 / 50 30 50 30
FORT LAUDERDALE  89  80  87  77 / 40 20 50 30
MIAMI            90  78  88  77 / 40 20 50 30
NAPLES           91  75  88  74 / 60 40 60 30

&&

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

$$

DISCUSSION/MARINE/FIRE...52/PS
AVIATION/RADAR...84/AK






AREA FORECAST DISCUSSION

NWS CHARLESTON SC

 406 AM EDT SAT AUG 24 2013

.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH SOUTH THROUGH THE AREA TODAY AND
BE  FOLLOWED BY COOLER AND DRIER CONDITIONS THROUGH EARLY NEXT
WEEK. ANOTHER WEAK COLD FRONT COULD APPROACH FROM THE NORTH LATE
NEXT WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
THROUGH SUNRISE...24/06Z SURFACE ANALYSIS PLACED THE COLD ACROSS
THE CENTRAL MIDLANDS INTO THE PEE DEE REGION OF NORTHEAST SOUTH
CAROLINA. THE FRONT IS MOVING SLOWLY SOUTH IN RESPONSE TO PHASED
SHORTWAVE ENERGY PASSING OFF THE MID-ATLANTIC COAST. SCATTERED
SHOWERS/TSTMS ARE SLOWLY DEVELOPING FROM NEAR COLUMBIA EAST TO
NORTH MYRTLE BEACH. THIS ACTIVITY IS DEVELOPING WITHIN A TONGUE OF
ENHANCED INSTABILITY AND LOW-LEVEL CONVERGENCE EXTENDING FROM THE
EASTERN MIDLANDS INTO THE CHARLESTON TRI-COUNTY AREA. THE LATEST
RUNS OF THE H3R AND RAP WITH SUPPORT FROM THE LATEST 4KM NSSL WRF
SHOW CONVECTION MEANDERING SOUTHEAST OVER THE NEXT SEVERAL
HOURS...PASSING NEAR OR JUST TO THE EAST OF THE CHARLESTON METRO
AREA. WILL SHOW THE HIGHEST POPS--UP TO 40 PERCENT--IN THIS AREA
THROUGH SUNRISE WITH SLIGHT CHANCE POPS EXTENDING AS FAR SOUTH AS
THE SAVANNAH RIVER. LOWS IN THE LOWER 70S INLAND TO UPPER 70S AT
THE BEACHES LOOK ON TRACK.

TODAY...THE BACKDOOR COLD FRONT WILL MEANDER SLOWLY SOUTH ACROSS
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA AS SHORTWAVE ENERGY
PROPAGATES FARTHER OFFSHORE. HIGH PRESSURE IS FORECAST TO
GRADUALLY WEDGE INTO THE REGION FROM THE NORTHEAST BEHIND THE
FRONT...BUT THIS WILL BE A VERY SLOW PROCESS. IN FACT...THE FRONT
DOES NOT LOOK TO CLEAR THE SAVANNAH METRO AREA UNTIL LATE THIS
AFTERNOON AND THE ALTAMAHA RIVER THIS EVENING AS IT BECOME
INTERMINGLED WITHIN THE SEA BREEZE CIRCULATION. ALOFT...HEIGHTS
WILL SLOWLY INCREASE IN RESPONSE TO A VERY LARGE...VERTICALLY
STACKED ANTICYCLONE CENTERED OVER THE CENTRAL PLAINS BUILDING EAST.
AS THE FRONT DRAGS SOUTH AND SUBSIDENCE/DRY AIR BEGINS TO ADVECT
IN ALOFT...THE PROSPECT FOR WIDESPREAD CONVECTIVE RAINS LOOKS
SLIM. EXPECT ONLY ISOLATED TO SCATTERED SHOWERS/TSTMS AT BEST WITH
THE GREATEST COVERAGE OCCURRING ALONG AND SOUTH OF THE COLD FRONT.
FARTHER NORTH...RAIN CHANCES LOOK TO END BY LATE MORNING AS
DEWPOINTS FALL SLIGHTLY. WILL UTILIZE A 20/40 POP REGIME FOR TODAY
WITH THE HIGHEST GRIDDED POPS CLUSTERED DOWN ALONG THE ALTAMAHA
RIVER WHERE THE ALIGNMENT OF MOISTURE...LIFT AND INSTABILITY WILL
BE THE MOST IDEAL. HIGH WILL RANGE FROM THE MID 80S ACROSS THE
CHARLESTON TRI-COUNTY AREA TO THE UPPER 80S/NEAR 90 ELSEWHERE.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
TONIGHT...THE COLD FRONT WILL GRADUALLY CLEAR THE ALTAMAHA RIVER
AS A WEDGE OF HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. RAIN
CHANCES WILL DIMINISH WITH TIME...HOWEVER THERE WILL BE ENOUGH OF
A MOIST...ONSHORE FLOW TO SUPPORT AT LEAST ISOLATED SHOWERS/TSTMS
ACROSS THE GEORGIA COASTAL COUNTIES THROUGH SUNRISE SUNDAY.
CLEARING WILL ALSO ENSUE FROM NORTH TO SOUTH...ALTHOUGH MOSTLY
CLOUDY SKIES WILL LIKELY LINGER ALONG NORTH COASTAL GEORGIA FOR A
GOOD PORTION OF THE NIGHT. LOWS WILL RANGE FROM THE MID 60S ACROSS
NORTHERN PORTIONS OF BERKELEY/DORCHESTER COUNTIES TO THE MID 70S
ALONG COASTAL GEORGIA. WINDS WILL BECOME BREEZY AT TIMES ALONG THE
BEACHES AS THE GRADIENT PINCHES IN RESPONSE TO HIGH PRESSURE
WEDGING INTO THE REGION. THIS WILL BE ESPECIALLY TRUE ALONG THE
BEACHES OF CHARLESTON COUNTY WHERE WINDS COULD BE 15-25 MPH WITH
GUSTS TO 30 MPH FOR MUCH OF THE OVERNIGHT HOURS.

SUNDAY...SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD FROM THE
NORTH. SOLID NORTHEAST FLOW WILL ADVECT A COOLER AND DRIER AIR
MASS INTO THE REGION...WITH TEMPERATURES ONLY REACHING THE MID
80S...AND AFTERNOON DEWPOINTS FALLING INTO THE LOW 60S NORTH TO
AROUND 70 SOUTH. HAVE CONFINED ANY SLIGHT TO LOW THUNDERSTORM
CHANCES MAINLY SOUTH OF THE SAVANNAH RIVER...CLOSEST TO LINGERING
MOISTURE AND CONVERGENCE WITHIN THE VICINITY OF THE FRONTAL ZONE.
EXPECT ALL LAND ZONES TO BE RAIN FREE BY THE EVENING HOURS...AS
FRONTAL FORCING CONTINUES TO SHIFT FARTHER AWAY FROM THE FORECAST
AREA. LOW TEMPERATURES WILL FALL NEARLY 10 DEGREES BELOW
AVERAGE...REACHING THE LOW TO MID 60S INLAND.

MONDAY...A FAIRLY UNSEASONAL PATTERN WILL PERSIST...SUPPORTING
RELATIVELY COOL AND DRY CONDITIONS FOR LATE AUGUST. THE CENTER OF
SURFACE HIGH PRESSURE WILL SLIP DIRECTLY OVER THE FORECAST AREA BY
MONDAY...WHILE STRONG UPPER RIDGING ENCOMPASSES MUCH OF THE
CENTRAL UNITED STATES. AFTERNOON DEWPOINTS IN THE LOW TO MID 60S
ARE EVIDENCE OF THE DRY AIR LINGERING OVER THE REGION...AND
LACKING ANY NOTABLE FORCING MECHANISMS...EXPECT ANOTHER RAIN FREE
DAY WITH POPS BELOW 15 PERCENT. TEMPERATURES WILL BE SUPPRESSED
WELL BELOW SEASONAL NORMALS...PEAKING ONLY IN THE MID 80S DESPITE
MOSTLY CLEAR TO PARTLY SKIES. RADIATIONAL COOLING WILL BE
EFFICIENT MONDAY NIGHT CONSIDERING LIGHT WINDS AND MOSTLY CLEAR
SKIES...ALLOWING LOW TEMPERATURES TO ONCE AGAIN FALL INTO THE 60S
ACROSS THE FORECAST AREA.

TUESDAY...THE PATTERN WILL BEGIN TO TRANSITION...AS SURFACE HIGH
PRESSURE CONTINUES TO SHIFT SOUTHWARD AND WEAKEN...WHILE A TROUGH
DEVELOPS OVER THE MID ATLANTIC AND CAROLINAS. HIGH TEMPERATURES
WILL MODERATE A FEW DEGREES INTO THE UPPER 80S AWAY FROM THE
COAST...YET ENOUGH DRY AIR WILL REMAIN TO SUPPRESS CONVECTIVE
DEVELOPMENT ONCE AGAIN. HAVE THUS CAPPED POPS BELOW 15 PERCENT ON
TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A TROUGH AT THE SURFACE AND ALOFT WILL STEADILY STRENGTHEN ALONG
THE EAST COAST MID TO LATE WEEK...ASSISTING IN THE DESCENT OF A
BACKDOOR FRONT INTO THE AREA BY THURSDAY OR FRIDAY. FAIRLY
SIGNIFICANT TIMING DIFFERENCES IN THE PROGRESSION OF THE FRONT ARE
EVIDENT IN MEDIUM RANGE MODEL SOLUTIONS...LENDING MORE UNCERTAINTY
TO FORECAST DETAILS FOR THE LATE WEEK PERIOD. WILL CONTINUE TO CAP
RAIN CHANCES BELOW 15 PERCENT THROUGH WEDNESDAY NIGHT...BEFORE
MOISTURE AND CONVERGENCE BECOMES ENHANCED AHEAD AND ALONG THE
APPROACHING FRONT THURSDAY AND FRIDAY. WILL REMAIN RATHER
GENERIC WITH POPS FOR THE LATE WEEK PERIOD CONSIDERING MODEL
DISCREPANCIES...INDICATING A SLIGHT CHANCE OF THUNDERSTORMS BY
THURSDAY AFTERNOON AND A SOLID CHANCE BY FRIDAY AFTERNOON. MODELS
ARE IN AGREEMENT THAT THE FRONT WILL LIKELY BE SOUTH OF THE AREA
BY SATURDAY. TEMPERATURES WILL HAVE MODERATED BACK TO NEAR
SEASONAL NORMALS DURING THE EXTENDED PERIOD...WITH HIGHS GENERALLY
IN THE UPPER 80S TO AROUND 90 DEGREES.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED AT THE TERMINALS. WILL BE WATCHING FOR
CONVECTION CROPPING UP LATER TONIGHT ALONG AND AHEAD OF A COLD
FRONT WHICH WILL BE SAGGING SOUTH THROUGH THE CAROLINAS. THE
BETTER CHANCES FROM LATER TONIGHT TO EARLY SAT AFTERNOON APPEAR TO
BE AT KCHS THROUGH MID-MORNING AND FROM LATE MORNING TO LATER IN
THE AFTERNOON AT KSAV. TSTMS POSSIBLE BUT CONFIDENCE IS LOW. FOR
NOW...WE HAVE JUST TIMED VCSH AT KCHS WHERE CONFIDENCE FOR
POSSIBLE IMPACTS IS THE HIGHEST. EXPECT VFR CONDITIONS TO PERSIST
OUTSIDE OF ANY CONVECTIVE RAINS ON SATURDAY.

EXTENDED AVIATION OUTLOOK...THERE IS A GOOD CHANCE OF BRIEF SUB-VFR
CONDITIONS WITH SHOWERS AND THUNDERSTORMS SATURDAY.

&&

.MARINE...
TODAY...LIGHT WINDS WILL GRADUALLY TURN NORTHEAST ACROSS THE SOUTH
CAROLINA WATERS AS A COLD FRONT DROPS SOUTH. THE FRONT LOOKS TO
GET HUNG UP NEAR THE SAVANNAH RIVER ENTRANCE BY EARLY AFTERNOON AS
A WEAK SEA BREEZE CIRCULATION MOVES INLAND. WINDS WILL LIKELY
REMAIN QUITE LIGHT OVER THE GEORGIA WATERS FOR MUCH OF THE DAY
OUTSIDE OF TSTMS. BOTH WINDS AND SEAS WILL REMAIN WELL BELOW SMALL
CRAFT ADVISORY THRESHOLDS...ALTHOUGH WINDS TO 35 KT AND FREQUENT
CLOUD TO WATER LIGHTNING COULD OCCUR WITH ANY TSTMS THAT FORM
AHEAD OF THE FRONT.

TONIGHT...CONDITIONS WILL DETERIORATE OVER THE WATERS TONIGHT AS
THE COLD FRONT FINALLY CLEARS THE SOUTHERN WATERS AND HIGH
PRESSURE WEDGES INTO THE REGION. THE PRESSURE GRADIENT LOOKS TO
TIGHTEN PRETTY SUBSTANTIALLY BY LATE EVENING AND MOST AVAILABLE
GUIDANCE SUPPORTS A MODEST NORTHEAST SURGE WORKING DOWN THE COAST
THROUGH THE OVERNIGHT HOURS. MODELS TYPICALLY UNDERPLAY THIS TYPE
OF PINCHED GRADIENT REGIME AND WITH BOTH MMG AND MME GUIDANCE
PACKAGES ALREADY SUPPORTING WINDS NEAR 20 KT...IT WILL NOT TAKE
MUCH MORE TO GET WINDS INTO FLAG THRESHOLDS. IN ADDITION...SEAS
WILL BUILD QUICKLY IN THE NORTHEAST FLOW WITH LOCAL SWAN OUTPUT
SHOWING 6 FT SEAS REACHING TO WITHIN 15 NM OF THE COAST AFTER
MIDNIGHT. GIVEN THESE FACTORS...WILL HOIST A SMALL CRAFT ADVISORY
FOR BOTH SOUTH CAROLINA NEARSHORE ZONES...EXCLUDING THE CHARLESTON
HARBOR FOR TONIGHT. CONDITIONS LOOK TO REMAIN BELOW THRESHOLDS FOR
THE GEORGIA WATERS AT LEAST THROUGH TONIGHT...ALTHOUGH IT MAY BE
CLOSE.

SUNDAY THROUGH WEDNESDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
CONTINUE INTO SUNDAY...AS THE PRESSURE GRADIENT REMAINS TIGHT
ALONG THE PERIPHERY OF HIGH PRESSURE BUILDING FROM THE NORTH. AT
LEAST MODERATE NORTHEAST FLOW WILL PERSIST INTO MONDAY...BEFORE
THE GRADIENT RELAXES ONCE HIGH PRESSURE BECOMES CENTERED OVER THE
FORECAST AREA. SEAS WILL BUILD TO 3 TO 5 FT NEARSHORE AND 5 TO 6
FT BEYOND 20 NM EARLY SUNDAY...THEN STEADILY SUBSIDE FOR THE
REMAINDER OF THE PERIOD.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 8 PM EDT SUNDAY FOR AMZ352.
     SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 8 PM EDT
     SUNDAY FOR AMZ350.

&&

$$

ST/WMS





AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 120 AM EDT SAT AUG 24 2013

.SYNOPSIS...
A COLD WILL MOVE THROUGH THE AREA TONIGHT AND INTO EARLY SATURDAY.
HIGH PRESSURE WILL BUILD INTO THE REGION OVER THE WEEKEND AND BRING
DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THROUGH 3 AM...CONVECTIVE ACTIVITY STARTING TO PICK UP IN ADVANCE
OF COLD FRONT MOVING THROUGH THE REGION. RUC MODEL SHOWING SHORT
WAVE STRENGTHENING AS IT MOVES S-SE ACROSS THE REGION. CAE RADAR
SHOWING COVERAGE PICKING UP TO THE NORTH OF CAE. DECIDED TO GO
LIKELY IN THE LINE OF ACTIVITY AS IT MOVES SOUTH. OTHERWISE...
BOTH RUC AND NAM MODEL SOUNDINGS GAVE CAPES AROUND 3500 J/KG NEAR
06Z.

REST OF OVERNIGHT PERIOD...WITH FRONT MOVING ON TO THE SOUTH...
THE 20-30 PERCENT POPS STILL LOOKED OK. EXPECT LOWS NEAR 70.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS THE MAIN BACKDOOR COLD FRONT CONTINUES PUSHING SOUTHWARD
THROUGH THE AREA...THE BEST CHANCE FOR PRECIPITATION WILL SHIFT TO
THE SOUTHERN HALF OF THE FORECAST AREA AS DRIER AIR TRIES TO
FILTER IN ACROSS THE NORTH. PRECIPITATION WILL COME TO AN END
ACROSS THE AREA BY SATURDAY EVENING AS THE FRONT PUSHES FARTHER TO
THE SOUTH. MAXIMUM TEMPERATURES SLIGHTLY BELOW NORMAL IN THE MID
TO UPPER 80S. OVERNIGHT LOWS SATURDAY NIGHT WILL RANGE FROM THE
MID 60S NORTH TO AROUND 70 SOUTH.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
THE WEATHER PATTERN REMAINS DRY AS HIGH PRESSURE BEGINS TO BUILD
INTO THE AREA INTO THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE WILL
BUILD ACROSS THE CENTRAL CONUS AND NUDGE EASTWARD AS THE UPPER
TROUGH REMAINS WELL OFF THE EAST COAST. BY LATE WEEK THE UPPER
RIDGE BEGINS TO RETROGRADE TO THE WEST ALLOWING AN UPPER TROUGH TO
REBUILD OVER THE EAST COAST. THIS WILL RESULT IN AN INCREASED
CHANCE FOR PRECIPITATION THURSDAY INTO FRIDAY. HIGH TEMPERATURES
MONDAY THROUGH WEDNESDAY MAINLY IN THE MID TO UPPER 80S...AND
AROUND 90 THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE
MIDDLE TO UPPER 60S EARLY TUESDAY AND WEDNESDAY MORNINGS...AND IN
THE LOWER 70S BY LATE WEEK.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...

FRONTAL BOUNDARY ACROSS THE NORTHERN FA WILL PUSH SLOWLY SOUTH
OVERNIGHT...WITH SCT TSRA POSSIBLE OVER THE NEXT FEW HOURS. LATEST
HIGH RESOLUTION MODELS SUGGEST LOWER CLOUDS DEVELOPING TO OUR NE AND
SHIFTING SW INTO OUR FA TOWARDS DAYBREAK. CURRENT OBS CONFIRM SOME
CLOUDS ACROSS NC WITH MAINLY MVFR CIGS. FOR NOW...WILL INDICATE A
PERIOD OF MVFR CIGS FOR OUR TERMINALS LATE TONIGHT AND TOWARDS
DAYBREAK...GRADUALLY LIFTING DURING THE MORNING. IFR CIGS PSBL BUT
WILL WAIT TO INCLUDE IN TAFS IF/WHEN CONFIDENCE WARRANTS. WINDS WILL
SHIFT TO N AND NE BEHIND THE FRONT...BUT LIGHT WINDS ALONG AND AHEAD
OF THE FRONT AT OGB/AGS COULD SPELL A SLIGHT FOG THREAT...BUT THINK
HIGH LEVEL CLOUDINESS WILL PRECLUDE THREAT.

FRONT TO CONTINUE SLOWLY SHIFTING SOUTH TODAY...WITH BETTER
INSTABILITIES AND MOST TSRA LATER TODAY AND THIS AFTERNOON TO BE
MAINLY TO OUR S AND SW. CHANCES TOO LOW TO INCLUDE MENTION IN THE
TAFS AT THIS TIME.

EXTENDED AVIATION OUTLOOK...SATURDAY NIGHT THROUGH THURSDAY...NO
SIGNIFICANT IMPACTS EXPECTED AT THIS TIME.

&&

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

$$







AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 109 AM EDT SAT AUG 24 2013

.SYNOPSIS...
A COLD WILL MOVE THROUGH THE AREA TONIGHT AND INTO EARLY SATURDAY.
HIGH PRESSURE WILL BUILD INTO THE REGION OVER THE WEEKEND AND BRING
DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THROUGH 3 AM...CONVECTIVE ACTIVITY STARTING TO PICK UP IN ADVANCE
OF COLD FRONT MOVING THROUGH THE REGION. RUC MODEL SHOWING SHORT
WAVE STRENGTHENING AS IT MOVES S-SE ACROSS THE REGION. CAE RADAR
SHOWING COVERAGE PICKING UP TO THE NORTH OF CAE. DECIDED TO GO
LIKELY IN THE LINE OF ACTIVITY AS IT MOVES SOUTH. OTHERWISE...
BOTH RUC AND NAM MODEL SOUNDINGS GAVE CAPES AROUND 3500 J/KG NEAR
06Z.

REST OF OVERNIGHT PERIOD...WITH FRONT MOVING ON TO THE SOUTH...
THE 20-30 PERCENT POPS STILL LOOKED OK. EXPECT LOWS NEAR 70.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS THE MAIN BACKDOOR COLD FRONT CONTINUES PUSHING SOUTHWARD
THROUGH THE AREA...THE BEST CHANCE FOR PRECIPITATION WILL SHIFT TO
THE SOUTHERN HALF OF THE FORECAST AREA AS DRIER AIR TRIES TO
FILTER IN ACROSS THE NORTH. PRECIPITATION WILL COME TO AN END
ACROSS THE AREA BY SATURDAY EVENING AS THE FRONT PUSHES FARTHER TO
THE SOUTH. MAXIMUM TEMPERATURES SLIGHTLY BELOW NORMAL IN THE MID
TO UPPER 80S. OVERNIGHT LOWS SATURDAY NIGHT WILL RANGE FROM THE
MID 60S NORTH TO AROUND 70 SOUTH.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
THE WEATHER PATTERN REMAINS DRY AS HIGH PRESSURE BEGINS TO BUILD
INTO THE AREA INTO THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE WILL
BUILD ACROSS THE CENTRAL CONUS AND NUDGE EASTWARD AS THE UPPER
TROUGH REMAINS WELL OFF THE EAST COAST. BY LATE WEEK THE UPPER
RIDGE BEGINS TO RETROGRADE TO THE WEST ALLOWING AN UPPER TROUGH TO
REBUILD OVER THE EAST COAST. THIS WILL RESULT IN AN INCREASED
CHANCE FOR PRECIPITATION THURSDAY INTO FRIDAY. HIGH TEMPERATURES
MONDAY THROUGH WEDNESDAY MAINLY IN THE MID TO UPPER 80S...AND
AROUND 90 THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE
MIDDLE TO UPPER 60S EARLY TUESDAY AND WEDNESDAY MORNINGS...AND IN
THE LOWER 70S BY LATE WEEK.

&&

.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
MAINLY VFR CONDITIONS CONTINUE ACROSS THE AREA THIS EVENING. AT THE
SURFACE...A WEAK SURFACE TROUGH IS LOCATED ACROSS THE MIDLANDS WITH
THE MAIN COLD FRONT ALONG THE CAROLINA BORDER. AHEAD OF THE FRONT
THE AIR MASS IS UNSTABLE AND SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED. DECIDED TO INCLUDE MENTION THUNDERSTORMS IN THE
VICINITY OF CAE AND CUB THROUGH 06Z. WINDS WILL BE VARIABLE...
BUT A GRADUAL WIND SHIFT TO THE NORTH/NORTHEAST WILL OCCUR BEHIND
THE FRONT. WILL MENTION A PERIOD OF MVFR CONDITIONS AT OGB/AGS
SATURDAY MORNING...BUT SOME MIXED SIGNALS WITH POTENTIAL CLOUD
COVER WITH BOUNDARY AND 20 KT LOW LEVEL JET TOWARD MORNING. ON
SATURDAY...EXPECT SCT/BKN CLOUDS BECOMING SCATTERED BY THE
AFTERNOON AS SOME DRIER AIR BEGINS TO MOVE INTO THE REGION FROM
THE NORTH. SURFACE WINDS WILL SHIFT TO THE NE AT 5 TO 10 KNOTS.

EXTENDED AVIATION OUTLOOK...NO RESTRICTIONS TO AVIATION EXPECTED AT
THIS TIME.

&&

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

$$







AREA FORECAST DISCUSSION

NWS COLUMBIA SC

 1205 AM EDT SAT AUG 24 2013

.SYNOPSIS...
A COLD WILL MOVE THROUGH THE AREA TONIGHT AND INTO EARLY SATURDAY.
HIGH PRESSURE WILL BUILD INTO THE REGION OVER THE WEEKEND AND BRING
DRY WEATHER THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THROUGH 3 AM...CONVECTIVE ACTIVITY STARTING TO PICK UP IN ADVANCE
OF COLD FRONT MOVING THROUGH THE REGION. ACTIVITY TO THE NORTH OF
CAE AND ON TOWARD CAMDEN. LIGHTNING DETECTION SHOWS SOME
LIGHTNING. BOTH RUC AND NAM MODEL SOUNDINGS GAVE CAPES AROUND 3500
J/KG NEAR 06Z. DECIDED TO INCREASE POPS TO 50 PERCENT BASICALLY
IN A LINE FROM FROM MCCORMICK COUNTY IN THE WEST TO LEXINGTON AND
RICHLAND COUNTIES AND ON EAST TO KERSHAW AND LEE COUNTIES.

REST OF OVERNIGHT PERIOD...WITH FRONT MOVING ON TO THE SOUTH...
THE 20-30 PERCENT POPS STILL LOOKED OK. EXPECT LOWS NEAR 70.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS THE MAIN BACKDOOR COLD FRONT CONTINUES PUSHING SOUTHWARD
THROUGH THE AREA...THE BEST CHANCE FOR PRECIPITATION WILL SHIFT TO
THE SOUTHERN HALF OF THE FORECAST AREA AS DRIER AIR TRIES TO
FILTER IN ACROSS THE NORTH. PRECIPITATION WILL COME TO AN END
ACROSS THE AREA BY SATURDAY EVENING AS THE FRONT PUSHES FARTHER TO
THE SOUTH. MAXIMUM TEMPERATURES SLIGHTLY BELOW NORMAL IN THE MID
TO UPPER 80S. OVERNIGHT LOWS SATURDAY NIGHT WILL RANGE FROM THE
MID 60S NORTH TO AROUND 70 SOUTH.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
THE WEATHER PATTERN REMAINS DRY AS HIGH PRESSURE BEGINS TO BUILD
INTO THE AREA INTO THE MIDDLE OF NEXT WEEK. AN UPPER RIDGE WILL
BUILD ACROSS THE CENTRAL CONUS AND NUDGE EASTWARD AS THE UPPER
TROUGH REMAINS WELL OFF THE EAST COAST. BY LATE WEEK THE UPPER
RIDGE BEGINS TO RETROGRADE TO THE WEST ALLOWING AN UPPER TROUGH TO
REBUILD OVER THE EAST COAST. THIS WILL RESULT IN AN INCREASED
CHANCE FOR PRECIPITATION THURSDAY INTO FRIDAY. HIGH TEMPERATURES
MONDAY THROUGH WEDNESDAY MAINLY IN THE MID TO UPPER 80S...AND
AROUND 90 THURSDAY AND FRIDAY. OVERNIGHT LOWS WILL BE IN THE
MIDDLE TO UPPER 60S EARLY TUESDAY AND WEDNESDAY MORNINGS...AND IN
THE LOWER 70S BY LATE WEEK.

&&

.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
MAINLY VFR CONDITIONS CONTINUE ACROSS THE AREA THIS EVENING. AT THE
SURFACE...A WEAK SURFACE TROUGH IS LOCATED ACROSS THE MIDLANDS WITH
THE MAIN COLD FRONT ALONG THE CAROLINA BORDER. AHEAD OF THE FRONT
THE AIR MASS IS UNSTABLE AND SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED. DECIDED TO INCLUDE MENTION THUNDERSTORMS IN THE
VICINITY OF CAE AND CUB THROUGH 06Z. WINDS WILL BE VARIABLE...
BUT A GRADUAL WIND SHIFT TO THE NORTH/NORTHEAST WILL OCCUR BEHIND
THE FRONT. WILL MENTION A PERIOD OF MVFR CONDITIONS AT OGB/AGS
SATURDAY MORNING...BUT SOME MIXED SIGNALS WITH POTENTIAL CLOUD
COVER WITH BOUNDARY AND 20 KT LOW LEVEL JET TOWARD MORNING. ON
SATURDAY...EXPECT SCT/BKN CLOUDS BECOMING SCATTERED BY THE
AFTERNOON AS SOME DRIER AIR BEGINS TO MOVE INTO THE REGION FROM
THE NORTH. SURFACE WINDS WILL SHIFT TO THE NE AT 5 TO 10 KNOTS.

EXTENDED AVIATION OUTLOOK...NO RESTRICTIONS TO AVIATION EXPECTED AT
THIS TIME.

&&

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

$$







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 218 AM MDT SAT AUG 24 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 593DM RIDGE CENTERED
OVER THE CENTRAL CONUS...WITH THE MEAN STORM THRACE WELL NORTH AND
WEST OF THE TRI-STATE REGION.

H5 RIDGE WILL STRENGTHEN TO 595-596DM BY SUN/MON AND REMAIN OVER
KS...KEEPING LARGE SCALE SUBSIDENCE IN PLACE...AND GENERALLY STABLE
CONDITIONS ACROSS THE CWA. STRENGTHENING LEE TROUGH WILL KEEP
BREEZY-WINDY CONDITIONS IN PLACE THROUGH EARLY NEXT WEEK AND STRONG
WAA ACROSS OUR CWA. PRIMARY FORECAST CHALLENGE IS HIGH/LOW TEMPS AND
MARGINAL FIRE WEATHER CONDITIONS.

BASED ON H85 TEMPS NEARING 30-31C EACH AFTERNOON WE SHOULD SEE HIGHS
WELL ABOVE NORMAL IN THE UPPER 90S/NEAR 100F EACH DAY. ONCE THIS
PATTERN IS ESTABLISHED WE SHOULD GET A BETTER HANDLE ON MIXING/H85
BIAS WHICH SHOULD MAKE THINGS A LITTLE EASIER...HOWEVER FOR NOW I
KEPT FORECAST CLOSE TO GUIDANCE. REGARDING LOW TEMPS...WITH
OVERNIGHT WINDS LIKELY REMAINING BREEZING (ESPECIALLY EAST) WE
SHOULDNT SEE AS MUCH COOLING AS MOS GUIDANCE WOULD INDICATE...SO I
TRENDED FORECAST TOWARDS ECMWF 2M GUIDANCE WHICH SEEMS TO BETTER
REFLECT THIS WARMER TREND.

REGARDING FIRE WEATHER...USING A CONSERVATIVE MIXING HEIGHT I HAVE
RH VALUES IN THE UPPER TEENS IN THE WEST THROUGH EARLY NEXT WEEK.
WITH LOWE TD/RH VALUES ALONG AND BEHIND TROUGH AXIS AND STRONGER
WINDS TO THE EAST...I AM NOT CURRENTLY ANTICIPATING MEETING THE 3HR
REQUIREMENT FOR RFW.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

A BROAD UPPER LEVEL RIDGE WILL BE WELL ESTABLISHED BY THE EXTENDED
PERIOD BEGINNING EARLY NEXT WEEK PROVIDING ABOVE NORMAL TEMPS AND
DRY CONDITIONS. IN GENERAL MODEL CONSENSUS HAS BEEN SOLID OVER THE
PAST FEW DAYS FOR THIS PERIOD...WITH THE ONLY REAL UNCERTAINTIES
BEING /1/ MAX TEMPS AND /2/ HOW THE RIDGE WILL EVOLVE LATE IN THE
WEEK.

IT LOOKS LIKE MAX TEMPS WILL PEAK EARLY IN THE WEEK...WITH
850MB TEMPS IN THE LOW 30S C AS THEY HAVE BEEN PROGGED FOR DAYS.
FULL SUNSHINE AND MIXING WILL LEAD TO HIGHS IN THE MID TO UPPER
90S...AND LOWS IN THE MID 60S IN EASTERN COLORADO TO LOW 70S FARTHER
EAST INTO KANSAS.

ADDRESSING THE SECOND POINT...WHILE THE OVERALL
PATTERN HAS BEEN CONSISTENT SOME OF THE FINE DETAILS TOWARDS THE END
OF THE WEEK ARE LOOKING A BIT LESS CERTAIN NOW. WHILE THE ECMWF AND
GEFS WERE MOVING THE RIDGE EAST AT THE END OF THE WEEK IN PAST
RUNS...THE 00Z GUIDANCE FROM GFS/GEFS/ECMWF ARE FAVORING MORE OF A
RETROGRADING RIDGE TO GO FROM CENTERED OVER KANSAS TOWARDS WESTERN
KANSAS. THIS WOULD LEAD TO A LESS FAVORABLE ENVIRONMENT FOR A
SURFACE TROUGH IN EASTERN CO AND ACCOMPANYING DEVELOPMENT OF BREEZY
SURFACE WINDS DURING THE DAY AND A MUCH WEAKER NOCTURNAL LLJ. IF
THIS PATTERN INDEED DEVELOPS THE DRY WEATHER WOULD PROBABLY EXTEND
THROUGH THE END OF THE MONTH.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1148 PM MDT FRI AUG 23 2013

VFR CONDITIONS ARE EXPECTED AT BOTH MCK AND GLD THROUGH THE TAF
PERIOD. SOUTH WINDS WILL INCREASE AFTER 14Z AND WILL REMAIN GUSTY
THROUGH ABOUT 02Z. AFTER ABOUT 02Z...WINDS WILL BECOME LIGHT OUT
OF THE SOUTH AGAIN.


&&

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

$$

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








AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1220 AM CDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1220 AM CDT SAT AUG 24 2013

LATEST SUITE OF SATELLITE IMAGERY AND LOCAL RADAR SUGGESTS THAT AN
AREA OF SHOWERS/THUNDERSTORMS IN SOUTHEAST MONTANA WILL CONTINUE
TO LIFT NORTHEAST OVERNIGHT...INTO SOUTHWEST AND WESTERN NORTH
DAKOTA. THIS IS IN LINE WITH THE LATEST HRRR MODEL. MODEL DATA
SUGGESTS THAT H85 WINDS ARE INCREASING NOW AND WILL MAINTAIN A
25KT TO 30KT PRESENCE THROUGH 09Z THEN TAPER OFF. THUS WILL KEEP
A CHC OF PRECIPITATION IN THE NORTH AHEAD OF THE WARM FRONT FOR
THE REST OF THE NIGHT. LITTLE CHANGES MADE FROM THE PREVIOUS
FORECAST.

LATER TODAY...WILL BE FOCUSING IN ON POSSIBLE HEAT ADVISORY FOR
SOUTH CENTRAL NORTH DAKOTA...WHICH IS FORECAST IN THE WARM SECTOR
WITH H85 TEMPS OF +27C TO +29C AND HIGHS AROUND 100 DEGREES.

UPDATE ISSUED AT 925 PM CDT FRI AUG 23 2013

LATE EVENING UPDATE FOR MINOR ADJUSTMENTS TO TEMPS AND POPS
OVERNIGHT. ONE ISOLATED CELL DEVELOPED NORTH OF GRASSY BUTTE THIS
EVENING BUT QUICKLY FELL APART DUE TO THE WARM AIR IN THE MID
LEVELS. HAVE MAINTAINED LOW POPS OVERNIGHT...ESPECIALLY
NORTH...BUT NOT OPTIMISTIC ABOUT ANYTHING MORE THAN ISOLATED
STORMS OVERNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 235 PM CDT FRI AUG 23 2013

FRIDAY AFTERNOON...A WARM FRONT ACROSS EASTERN MONTANA WAS POISED
TO MOVE EAST INTO WESTERN NORTH DAKOTA TONIGHT. THE FRONT WILL BE
THE FOCUS FOR SHOWERS AND THUNDERSTORMS. SO FAR TODAY...THE
ATMOSPHERE HAS BEEN TRANSITIONING FROM A COOLER AND DRYER AIR MASS
TO A WARMER AND MORE MOIST ONE. SOUNDING FORECASTS SHOW A STURDY
CAP IN PLACE ACROSS CENTRAL AND EAST. THIS WILL ERODE LATE THIS
AFTERNOON WEST. THE ADDITION OF MOISTURE HAS RESULTING IN GROWING
CU ACROSS THE EAST CENTRAL DESPITE THE CAP. DO NOT EXPECT THIS TO
AMOUNT TO MUCH THIS EVENING EAST. TONIGHT...THE WRF MODEL
GENERATES QUITE BIT OF CONVECTION ALONG AND AHEAD OF THE WARM
FRONT. THIS TOO WITH THE GFS. NAM A BIT DRIER. SATELLITE TRENDS SO
FAR SHOW CLOUDS AND THUNDERSTORMS IN CANADA SO BELIEVE THIS AREA
ALREADY NORTH OF THE CAP. KEPT THE HIGHEST POPS...40-50 NORTH AND
LOWEST SOUTH...GENERALLY FOLLOWING THE WARM FRONT AS IT PROGRESSES
EAST. THIS WILL BE FOLLOWED BY A COLD FRONT WEST LATE IN THE
AFTERNOON...WHICH WILL AGAIN BE THE FOCUS FOR SCATTERED
THUNDERSTORMS WEST SATURDAY AFTERNOON. MEANWHILE...THE WARM SECTOR
WILL BE OVER CENTRAL NORTH DAKOTA SATURDAY. HIGH WILL APPROACH 100
AND WITH HEAT INDEX VALUES NEAR 100 CONSIDERED A HEAT ADVISORY
FOR THE SOUTH CENTRAL COUNTIES ALONG THE SD BORDER.
HOWEVER...DEW POINTS ALREADY TRENDING DOWN SATURDAY SO THIS MAY
LIMIT THE HEAT INDEX BELOW 100. WILL HOLD OFF ON THE ADVISORY FOR
NOW.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 235 PM CDT FRI AUG 23 2013

MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.

THERE IS A CONTINUED AGREEMENT IN THE MEAN UPPER LEVEL FLOW WHICH
FEATURES A STRONG RIDGE OVER THE CENTRAL U.S. THIS WILL RESULT IN
TEMPERATURES WELL ABOVE NORMAL THROUGH THE EXTENDED PERIOD ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. DAYTIME HIGHS FROM THE UPPER 80S
TO LOWER 90S NORTH AND LOWER TO MID 90S SOUTH ARE EXPECTED. WITH
DEWPOINTS GENERALLY IN THE MID 50S TO 60S EACH DAY...AFTERNOON HEAT
INDICES WILL LIKELY APPROACH 100 DEGREES SUNDAY AND MONDAY IN THE
SOUTH CENTRAL AND IN THE JAMES RIVER BASIN.

MODELS CONTINUE TO HAVE DIFFICULTY RESOLVING SHORTWAVES TRANSLATING
THROUGH THE BROAD SOUTHWEST FLOW FROM THE WESTERN UPPER LOW INTO THE
NORTHERN PLAINS AND SOUTHERN CANADA. THEREFORE A MODEL BLEND WAS
UTILIZED FOR POPS THROUGH THE PERIOD. MODELS ARE TRYING TO DEVELOP
CONVECTION ON SATURDAY NIGHT AS THERE WILL BE A SURFACE TROUGH
TRACKING SLOWLY EAST ACROSS THE AREA THAT IS PROGGED TO BE OVER
CENTRAL NORTH DAKOTA BY 00 UTC SUNDAY...WITH SHORTWAVE ENERGY MOVING
INTO WESTERN NORTH DAKOTA. WE WILL HAVE ABUNDANT CAPE OVER THE AREA
SATURDAY AFTERNOON BUT WILL LIKELY REMAIN CAPPED UNTIL SHORTWAVE
ENERGY ARRIVES LATE IN THE DAY. THUS THE BEST THUNDERSTORM CHANCES
ON SATURDAY ARE EXPECTED TO BE IN THE EVENING AND OVERNIGHT. SOME OF
THESE COULD BE STRONG TO SEVERE.

TODAY`S MODELS GIVE A BIT OF A REPRIEVE FOR CONVECTION CHANCES ON
SUNDAY...WITH NO MAIN UPPER LEVEL SHORTWAVES IN THE FLOW AND WEAK
SURFACE HIGH PRESSURE OVER THE REGION.

THEREAFTER...THUNDERSTORM CHANCES CANNOT BE RULED OUT EACH DAY AS
THE LOWER ATMOSPHERE REMAINS MOIST AND UNSTABLE WITH SHORTWAVE
ENERGY CONTINUING TO TRAVERSE THE AREA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1220 AM CDT SAT AUG 24 2013

VFR CIGS EXPECTED...ALTHOUGH KJMS WILL LIKELY SEE PATCHY FOG
TOWARD 12Z AND POSSIBLE MVFR CIGS/VSBYS FOR A FEW HOURS. OTHERWISE
A VCTS IS FORECAST AT ALL AERODROMES WITH THE EXCEPTION OF KISN
AND KJMS. A COLD FRONT IS STILL ON TRACK TO SHIFT ACROSS THE
WESTERN AERODROMES BY AROUND 20Z-21Z SATURDAY...AND THE CENTRAL
TAF SITES BY AROUND 00Z SUNDAY.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...KS
SHORT TERM...WAA
LONG TERM...JV
AVIATION...KS







AREA FORECAST DISCUSSION

NWS GRAND FORKS ND

 1140 PM CDT FRI AUG 23 2013

.UPDATE...
ISSUED AT 1140 PM CDT FRI AUG 23 2013

NOT MUCH HAPPENING NOW PCPN WISE AND NOT LOOKING REALLY PROMISING
FOR MUCH FOR THE REMAINDER OF THE NIGHT. MODELS ARE REALLY
STRUGGLING TO MATCH UP WITH REALITY BUT THE GEM SEEMS TO BE DOING
BEST. RAP ALSO NOT DOING TOO BAD AND IT HAS LITTLE ELSE THRU THE
REST OF THE NIGHT. THEREFORE WILL CUT BACK TO ISOLATED
SHOWERS/TSTMS AND LET NEXT SHIFT WATCH.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 305 PM CDT FRI AUG 23 2013

FORECAST CHALLENGE FOR THE SHORT TERM WILL BE TEMPERATURES AND
POTENTIAL/PLACEMENT OF CONVECTION. A STATIONARY UPPER HIGH OVER
THE CENTRAL PLAINS IS YIELDING A SERIES OF MINOR SHORT WAVES
MOVING OUT OF THE SOUTHWEST CONUS AND INTO NORTHER TIER OF US.
MODELS ARE HAVING A DIFFICULT TIME WITH TIMING OF INDIVIDUAL WAVES
AS WELL AS PLACEMENT OF ASSOCIATED CONVECTION...THUS CONFIDENCE
FOR ANY SIGNIFICANT CONVECTION FOR ANY GIVEN AREA CONTINUES TO BE
LOW.

FOR TONIGHT...A WEAK VORT MAX OVER CNTRL MT WILL RIDE ALONG UPPER
RIDGE INTO NORTH CENTRAL ND/SOUTHERN MANITOBA TONIGHT. A WEAKER
VORT WILL MOVE ACROSS THE SOUTHERN VALLEY...BUT FEEL BEST CHANCE
FOR OVERNIGHT CONVECTION WILL BE ACROSS THE FAR NORTH WITH THE
COOLER H700 TEMPS. MODELS DO SHOW A SMALL AREA OF PRECIP
ASSOCIATED WITH SRN VORT/WARM ADVECTION DEVELOPING IN FAR SOUTHERN
VALLEY...WHERE BEST H850 MOISTURE TRANSPORT WILL HELP INCREASE
PWATS...HOWEVER STRONGEST LLJ FLOW WILL BE ACROSS SRN MN.

TOMORROW...WITH EXCEPTION OF 12Z NAM...MODELS MOVE FIRST WAVE OF
PRECIP OUT OF EASTERN ZONES BY MID MORNING WHILE THE NAM BRINGS A
SECOND WAVE INTO EASTERN ND BY MID DAY. CONSIDER THIS SOLUTION AN
OUTLIER AND WILL MAINTAIN A DRY FORECAST FOR THE VALLEY WEST DRG
THE DAY SATURDAY. WILL KEEP LOW CHANCE POPS IN THE EAST TO BETTER
BLEND WITH NEIGHBORS. CONTINUED WARM ADVECTION WILL BRING DAYTIME
HIGHS INTO THE UPPER 80S TO NEAR 90 IN THE SOUTH...WITH DEW POINTS
RISING INTO THE 60S...FOR A HOT AND HUMID DAY.

TOMORROW NIGHT...SFC TROUGH WILL MOVE INTO WRN ZONES WITH BEST
UPPER LEVEL ENERGY ACROSS NORTHERN ZONES AND SRN MB. WILL KEEP
SOUTHERN ZONES DRY AS STRONGER CAP SHOULD BE IN PLACE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 305 PM CDT FRI AUG 23 2013

SUNDAY AND MONDAY...WITH NO SIGNIFICANT CHANGE TO UPPER LEVEL
PATTERN...WILL CONTINUE TO SEE LOW CHANCES OF PRECIP ACROSS MAINLY
THE NORTHERN ZONES. TEMPS WILL RISE INTO 90S AND WITH JUICY
AIRMASS IN PLACE...HEAT ADVISORY CRITERIA IS POSSIBLE IN THE FAR
SOUTHERN VALLEY. BEYOND MONDAY...MODELS OVERALL IN REASONABLE AGREEMENT
THROUGH THE LONG RANGE. CENTER OF UPPER RIDGE TO REMAIN ACROSS
CENTRAL PLAINS THROUGH THE PERIOD. A COUPLE OF MORE SIGNIFICANT
WAVES WILL RIDE OVER THE RIDGE BRINGING MODEST RAIN CHANCES TO THE
REGION. FIRST WAVE LOOKS TO BE MONDAY NIGHT WITH ANOTHER ON
THURSDAY. TEMPERATURES TO REMAIN ABOVE TO WELL ABOVE AVERAGE
THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1140 PM CDT FRI AUG 23 2013

KEPT ANY MENTION OF PCPN OUT OF THE TAFS WITH LITTLE CONFIDENCE IN
ANYTHING HAPPENING. SOUTH WINDS SHOULD PICK UP AGAIN SAT MORNING
AND STAY UP THROUGH THE DAY.

&&

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

$$

UPDATE...GODON
SHORT TERM...SPEICHER
LONG TERM...SPEICHER/VOELKER
AVIATION...GODON







AREA FORECAST DISCUSSION

NWS MILWAUKEE/SULLIVAN WI

 355 AM CDT SAT AUG 24 2013

.TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

UPPER RIDGE BUILDING INTO THE REGION WITH WEAK SHORT WAVE PASSING
WELL NORTH OF FORECAST AREA. HRRR CURRENTLY HAS A BETTER HANDLE
THAN OPERATIONAL MODELS WITH PRECIPITATION OVER ERN
NEBRASKA...THAT WILL TRACK WITH BEST FRONTOGENETIC
FORCING/Q VECTOR CONVERGENCE/ISENTROPIC LIFT SHOWN ON ALL MODELS
TO THE W AND N OF CWA. THUS HAVE REMOVED SLIGHT POPS FROM THE WEST
FOR THIS AFTERNOON AND CHC POPS FOR TONIGHT ACROSS THE FAR NORTH.

925 MB TEMPERATURES WARM ABOUT 2C FROM YESTERDAY SO DECENT MIXING
WILL YIELD HIGHS IN THE MID TO UPPER 80S IN THE WEST...WITH AROUND
80 IN THE EAST AS WINDS OFF OF THE LAKE WILL HOLD READINGS DOWN.

EXPECT ENOUGH GRADIENT WIND AND SUFFICIENT DEW POINT DEPRESSION IN
THE WEST TO NOT HAVE FOG IN FORECAST...EVEN IN THE WISCONSIN RIVER
VALLEY. LIGHTER WINDS EAST MAY ALLOW SOME PATCHY FOG AROUND
SUNRISE.

.SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.

SHORT TERM MODELS SHOWING 500MB HIGH RETREATING FROM MISSOURI ON
SUNDAY TO KANSAS BY MONDAY NIGHT. THIS ALLOWS FOR WEST NORTHWEST
TO NORTHWEST FLOW AT THIS LEVEL OVER THE WESTERN GREAT LAKES
REGION. AT THE SURFACE...SOUTHWEST LOW LEVEL WINDS BRINGS VERY
WARM AIRMASS INTO THE REGION SUNDAY. AIRMASS IS EXPECTED TO BE
CAPPED.

925MB TEMPERATURES SUGGESTING HIGHS MAINLY AROUND 90 OR IN THE
LOWER 90S. DEW POINTS WILL ALSO BE IN THE LOWER TO MID 60S...WHICH
WILL GIVE HEAT INDEX VALUES IN THE 90 TO 95 RANGE ACROSS THE AREA.

NAM/GFS SHOW 500MB VORTICITY MAXIMUM SLIDING SOUTHEAST ACROSS
NORTHEAST PORTIONS OF THE FORECAST AREA LATER SUNDAY NIGHT.
NAM/GFS HAVE LIGHT QPF WITH THIS FEATURE DURING THIS TIME. ADDED
LOWER END POPS IN THE NORTHERN AND NORTHEASTERN COUNTIES FOR
MAINLY LATER SUNDAY NIGHT. LOWS WILL REMAIN WARM...IN THE LOWER 70S.

GFS/ECMWF/CANADIAN MODELS SHOW WARM FRONT STALLING OUT FROM
CENTRAL MINNESOTA INTO SOUTHEAST WISCONSIN MONDAY INTO MONDAY
NIGHT. THE NAM IS FURTHER SOUTHWEST THAN THE OTHER MODELS WITH THE
FRONTAL POSITION...PERHAPS TOO FAR SOUTHWEST. BEST FORCING FOR
UPWARD VERTICAL MOTION REMAINS WELL NORTHWEST AND NORTH OF THE
AREA DURING THIS TIME.

AREA FORECAST SOUNDINGS ARE SHOWING AMPLE MEAN LAYER CAPE/MODEST
DEEP LAYER SHEAR WITH A WEAK CAP MONDAY...BECOMING MORE ELEVATED
IN NATURE WITH THE CAPE MONDAY NIGHT. KEPT POPS GOING FOR THIS
PERIOD IN THE NORTHEAST HALF OF THE AREA...CLOSEST TO THE LOW
LEVEL FRONTOGENESIS RESPONSE FIELDS.

AREA REMAINS IN WARM SECTOR AIRMASS MONDAY INTO MONDAY NIGHT PER
GFS/ECMWF/CANADIAN MODELS. 925MB TEMPERATURES SUGGEST HIGHS IN THE
LOWER TO PERHAPS MID 90S MONDAY...WITH HEAT INDEX VALUES IN THE
95 TO 101 DEGREE RANGE.

.TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS MEDIUM.

GFS/ECMWF SHOW SOME DIFFERENCES WITH TRENDS DURING THIS PERIOD.
THE 500MB HIGH REMAINS OVER THE KANSAS AREA DURING THIS PERIOD.
THE GFS CONTINUES TO BE FURTHER SOUTH WITH THE PASSING LOW
PRESSURE SYSTEM AND FRONTAL BOUNDARY TUESDAY INTO TUESDAY NIGHT.
DECENT MEAN LAYER CAPES OF 1000 TO 1300 J/KG WITH DECENT DEEP
LAYER SHEAR AROUND 30 TO 35 KNOTS ARE SHOWN ON GFS FORECAST
SOUNDINGS. ECMWF IS DRY WITH THE FRONTAL PASSAGE.

BOTH MODELS DO SHOW COLD FRONT DROPPING SOUTHWARD THROUGH THE AREA
TUESDAY NIGHT. CONTINUED POPS FOR TUESDAY AND TUESDAY
NIGHT IN THE NORTHEASTERN HALF OF COUNTIES...CLOSEST TO THE LOW.

AREA REMAINS IN WARM SECTOR AIRMASS ON ECMWF AND GFS...WITH 925MB
TEMPERATURES SUPPORTING ANOTHER DAY OF LOWER TO PERHAPS MID 90S
FOR HIGHS. HEAT INDEX VALUES SHOULD REACH THE 95 TO 101 RANGE
AGAIN. COUNTING WEDNESDAY...THERE WOULD BE THREE DAYS IN A ROW OF
HEAT INDEX VALUES IN THE 95 TO 100 DEGREE RANGE IN SOUTH CENTRAL
WISCONSIN. NEED FOUR IN A ROW FOR A HEAT ADVISORY. IT STILL MAY BE
NEEDED FOR MONDAY AND TUESDAY ACROSS THE AREA...IF DAILY HEAT
INDEX VALUES CONTINUE TO REMAIN AROUND OR ABOVE 100. FOR
NOW...WILL CONTINUE MENTION POTENTIAL IN HAZARDOUS WEATHER
OUTLOOK AND SPECIAL WEATHER STATEMENT.

MODEST COLD AIR ADVECTION AHEAD OF HIGH PRESSURE PUSHES INTO THE
AREA WEDNESDAY ON NORTH TO NORTHEAST WINDS...BRINGING SLIGHTLY
COOLER BUT STILL ABOVE NORMAL TEMPERATURES. HIGH PRESSURE THEN
MOVES SLOWLY SOUTHEAST THROUGH THE REGION THROUGH
THURSDAY...BRINGING QUIET WEATHER AND WARM TEMPERATURES.

WARM AIR ADVECTION AND MOISTURE ADVECTION THEN TRY TO PUSH BACK
INTO PORTIONS OF THE REGION THURSDAY NIGHT INTO FRIDAY...MORE SO
ON ECMWF THAN GFS. USED CONSENSUS POPS FOR NOW IN THIS PERIOD.

&&

.AVIATION/12Z TAFS/...ONCE PATCHY MVFR FOG AT KENW AND KUES CLEARS
THIS MORNING...LOOKING AT VFR CONDITIONS THROUGH THE DAY. LIGHT
WINDS OVER THE EAST BRINGS POTENTIAL FOR PATCHY MVFR FOG
REDEVELOPMENT AT KENW TONIGHT...BUT DEW POINT DEPRESSIONS OF 4 TO
6 DEGREES WILL LIKELY PREVENT FORMATION SO WILL LEAVE OUT FOR NOW.

&&

.MARINE...STILL LOOKS LIKE BREEZY SOUTHWEST WINDS WILL APPROACH
SMALL CRAFT ADVISORY LEVELS ON SUNDAY...ESPECIALLY CLOSE TO SHORE.
WILL MENTION POTENTIAL IN FORECAST BUT NOT ISSUE A HEADLINE AT
THIS TIME.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

TODAY/TONIGHT AND AVIATION/MARINE...REM
SUNDAY THROUGH FRIDAY...WOOD







AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 320 AM CDT SAT AUG 24 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SAT AUG 24 2013

MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES.

CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING JUST
OFF THE PACIFIC NORTHWEST COAST AND OVER NEW ENGLAND...WHILE STRONG
SUBTROPICAL RIDGING DOMINATED THE CENTRAL AND SOUTHERN PLAINS.
NUMEROUS MONSOONAL SHORTWAVES WERE PRESENT ON THE WEST SIDE OF THE
RIDGE...FROM ARIZONA INTO WYOMING AND SOUTH DAKOTA. SOUTHERLY 850MB
WINDS OF 30-45 KT FROM KANSAS INTO WESTERN MN AHEAD OF THESE
SHORTWAVES ARE TRANSPORTING WARMER AND MORE MOIST AIR INTO THE UPPER
MIDWEST. PRECIPITABLE WATER VALUES HAVE CLIMBED TO 1.5-1.8 INCHES
FROM THE WESTERN PORTION OF THE FORECAST AREA INTO EASTERN PORTIONS
OF SOUTH DAKOTA AND NEBRASKA...PER SATELLITE DERIVED ESTIMATES.
MEANWHILE...850MB TEMPS HAVE CLIMBED TO 16-18C ACROSS THE FORECAST
AREA AND 22-28C ACROSS THE CENTRAL AND NORTHERN PLAINS PER RAP
ANALYSIS. THE GENERAL WARM ADVECTION PATTERN COMBINED WITH DPVA FROM
THE MONSOONAL SHORTWAVES HAS LED TO SOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WYOMING...NEBRASKA AND SOUTH DAKOTA.

SYNOPTIC OVERVIEW...
THE SUBTROPICAL RIDGE OVER THE CENTRAL PLAINS IS PROGGED OVER THE
NEXT 24 HOURS TO BUILD INTO MISSOURI AND STRENGTHEN...CAUSING 500MB
HEIGHTS TO RISE ABOUT 30 METERS OVER THE FORECAST AREA. FOR THE MOST
PART IT APPEARS THE MONSOONAL SHORTWAVES COMING FROM THE ROCKIES
LOOK TO TRACK ACROSS THE DAKOTAS INTO NORTHWEST ONTARIO. THE ONE
SHORTWAVE OVER SOUTH DAKOTA MODELS SHOWED YESTERDAY TO COME ACROSS
THE FORECAST AREA TODAY IS PRETTY MUCH NON-EXISTENT IN MODELS TODAY.
NEVERTHELESS...WITH THE BUILDING RIDGING...THE WARM ADVECTION
PATTERN ACROSS THE UPPER MIDWEST WILL CONTINUE.

DETAILS...
THE QUESTION TODAY IS THE CHANCES OF PRECIPITATION NOW THAT THE
SHORTWAVE FROM SOUTH DAKOTA IS NO LONGER PRESENT. THE SIGNAL FOR
POSSIBLE SHOWER/THUNDERSTORM INITIATION ON THE EASTERN EDGE OF THE
850MB MOISTURE TRANSPORT IS STILL THERE...SUGGESTED BETWEEN 09-15Z
IN THE 24.00Z NAM/REGIONAL CANADIAN AND GFS. AFTER THAT...MODELS
HAVE DEFINITELY TRENDED DRIER FOR THE REST OF THE DAY. THIS MAKES
SENSE WITH THE BUILDING HEIGHTS. NOW THE 24.00Z NAM DOES TRY TO
GENERATE SOME ISOLATED CONVECTION OVER THE NORTHWEST HALF OF THE
AREA LATE IN THE AFTERNOON. HOWEVER...LOOKING AT SOUNDINGS THIS
SEEMS TO BE COMPLETELY TIED TO THE CONVECTIVE SCHEME AND ODD...WITH
MLCIN DROPPING FROM 70-80 J/KG TO 0 J/KG IN 1 HOUR WHILE A SUBSIDENT
PROFILE IS PRESENT. GIVEN THE CONSENSUS FOR A DRY AFTERNOON...WENT
IN THIS DIRECTION. BULK OF THE CONVECTION ALSO LOOKS TO STAY NORTH
OF THE FORECAST AREA TONIGHT WITH THE 850MB MOISTURE TRANSPORT
STREAM MOVING OVERHEAD...WHILE ITS NOSE IS FOCUSED FROM NORTHERN MN
ACROSS LAKE SUPERIOR AND UPPER MI. HAVE SHIFTED CHANCES NORTH TO
ONLY INCLUDE TAYLOR/CLARK NOW...TO ACCOUNT FOR THE DRYING
TREND...AND THESE MIGHT BE ABLE TO BE SHIFTED COMPLETELY OUT OF THE
AREA.

PARTIAL SUNSHINE TODAY COMBINED WITH 925/850MB TEMPS ABOUT 2C WARMER
SHOULD ALLOW HIGHS TO TOP OUT SIMILAR TO OR JUST SLIGHTLY WARMER
COMPARED TO YESTERDAY. CONDITIONS WILL BE A BIT MORE
MUGGY...THOUGH...AS HIGHER DEWPOINTS IN THE UPPER 60S TO LOW 70S
ADVECT IN ON INCREASING SOUTHERLY WINDS. THE SOUTHERLY BREEZE IS
EXPECTED TO PERSIST INTO TONIGHT...ALLOWING THE AFOREMENTIONED
DEWPOINTS TO SPREAD ACROSS THE FORECAST AREA. THE HIGHER DEWPOINTS
AND BREEZE SHOULD HELP KEEP TEMPERATURES UP IN THE MID 60S TO LOW
70S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT AUG 24 2013

HAZARDS...
1. HEAT. CONFIDENCE REMAINS HIGH THAT HEAT INDICES WILL EXCEED
ADVISORY CRITERIA BOTH MONDAY AND TUESDAY. A FEW LOCALIZED SPOTS
COULD EVEN TOUCH EXCESSIVE HEAT WARNING CRITERIA OF 105.
ADDITIONALLY...SUNDAY NOW LOOKS A LITTLE HIGHER FOR HEAT INDICES...
MORE CLOSER TO 100. GIVEN THESE CONDITIONS AS WELL AS WARM OVERNIGHT
LOWS...HAVE ISSUED A HEAT ADVISORY FOR SUNDAY THROUGH TUESDAY.

2. STORMS. THERE ARE PERIODIC STORM CHANCES THROUGHOUT THE LONG TERM
PORTION OF THE FORECAST...PARTICULARLY NORTH/EAST OF I-94.
HOWEVER...0-6KM AND 0-3 KM SHEAR VALUES ARE NEVER THAT IMPRESSIVE...
GENERALLY 25 KT OR LESS. THIS WILL KEEP HEAVY RAIN AS THE MOST
LIKELY HAZARD FROM THE STORMS.

SYNOPTIC OVERVIEW...
THE STRONG SUBTROPICAL RIDGE OVER MISSOURI TO START AT 12Z SUNDAY IS
WELL AGREED UPON BY 24.00Z GUIDANCE TO RETROGRADE WESTWARD THROUGH
THE MIDDLE OF THE WEEK. THIS RETROGRESSION IS CAUSED BY A SERIES OF
SHORTWAVE TROUGHS DROPPING DOWN THE EAST SIDE OF THE RIDGE INTO NEW
ENGLAND...THE MOST IMPRESSIVE OF WHICH CROSSES NEAR THE GREAT LAKES
REGION TUESDAY NIGHT. THE RETROGRESSION DOESNT LAST LONG...
THOUGH...AS A MORE POTENT UPPER TROUGH COMES INTO THE PACIFIC
NORTHWEST LATE IN THE WEEK...HELPING TO PUSH THE RIDGING AND ITS
WARMTH BACK EASTWARD.

PRECIPITATION DETAILS...
SUNDAY CONTINUES TO LOOK DRY WITH ALL SHORTWAVE AND 850MB MOISTURE
TRANSPORT FORCING TRACKING ACROSS LAKE SUPERIOR OR FARTHER NORTH.
THE 24.00Z NAM...HIRES ARW/NMM INITIATES SURFACE BASED CONVECTION
OVER CENTRAL MN LATE SUNDAY AFTERNOON...ALONG A SURFACE TROUGH. THE
CONVECTION THEN DROPS SOUTH TOWARDS I-90 IN THE EVENING. THESE
APPEAR TO BE STRONGLY DRIVEN BY TEMPERATURES REACHING 100F OR SO
ALONG THE TROUGH...WHICH IS THE CONVECTIVE TEMPERATURE. WHETHER OR
NOT THIS HAPPENS IS UNKNOWN...BUT JUST IN CASE DID INCLUDE 20-40
PERCENT CHANCES ALONG/NORTH OF I-90 IN THE EVENING. THESE CHANCES
CONTINUE INTO THE OVERNIGHT HOURS FOR A SECOND SCENARIO...WHERE
CONVECTION FIRES UP IN NORTHWEST WISCONSIN IN THE EVENING AND DROPS
SOUTH FOLLOWING CORFIDI VECTORS. THIS IS PRESENTED BY THE 24.00Z
GFS/ECMWF. IT SHOULD BE NOTED...THOUGH...THE 24.00Z CANADIAN/UKMET
ARE DRY...KEEPING ALL CONVECTION TO THE NORTH OF THE AREA. ALSO
INTERESTING TO NOTE IS THAT THE NAM...GFS AND ECMWF ARE ALL DRY
MONDAY MORNING...SUGGESTING CONVECTION WEAKENS AS IT RUNS INTO THE
CAPPING OVER THE AREA.

ALL MODELS INDICATE THAT AN OUTFLOW BOUNDARY/WARM FRONT SHOULD BE
LOCATED SOUTH OF THE OVERNIGHT CONVECTION...SETTING UP NEAR I-94 FOR
MONDAY AFTERNOON. 24.00Z GFS/ECMWF BOTH FIRE SOME CONVECTION ALONG
THIS BOUNDARY WHICH WOULD APPEAR POSSIBLE GIVEN THE HOT AND HUMID
AIRMASS IMPINGING ON IT FROM THE SOUTHWEST. THEREFORE...CARRIED 20
PERCENT CHANCES ALONG/NORTH OF I-94 FOR THE AFTERNOON. THESE CHANCES
PERSIST THROUGH MONDAY NIGHT AND TUESDAY...AIDED BY INCREASING 850MB
MOISTURE TRANSPORT AHEAD OF A MORE SIGNIFICANT SHORTWAVE TRACKING
ACROSS THE DAKOTAS...INTO NW MINNESOTA AND LAKE SUPERIOR. GREATER
CHANCES FOR CONVECTION MONDAY NIGHT AND TUESDAY SHOULD STAY OFF TO
THE NORTH AND NORTHEAST CLOSER TO THAT SHORTWAVE TRACK.

A COLD FRONT IS PROGGED TO DROP THROUGH TUESDAY NIGHT. PLENTY OF
CAPPING AHEAD OF THE FRONT SHOULD RESTRICT SURFACE BASED CONVECTION
ON IT...WITH DRY CONDITIONS LIKELY IN ITS WAKE FOR WEDNESDAY INTO
THURSDAY. CHANCES OF SHOWERS AND STORMS RETURN THURSDAY NIGHT
THROUGH FRIDAY NIGHT AS THE FRONT GRADUALLY RETURNS BACK
NORTHEASTWARD AS A WARM FRONT.

TEMPERATURE DETAILS...
SUNDAY...WITH PLENTY OF SUN...BREEZY SOUTHWEST WINDS AND 925 MB
TEMPS CLIMBING TO 26-28C...HIGH TEMPS SHOULD EASILY TOP OUT IN THE
UPPER 80S TO LOW 90S. A FEW VALLEY LOCATIONS COULD EVEN HIT THE MID
90S. WITH DEWPOINTS LIKELY IN THE UPPER 60S TO LOW 70S...PEAK HEAT
INDICES OF 95 TO 100 SHOULD BE COMMON...HIGHEST OVER THE NORTHWEST
HALF OF THE FORECAST AREA.

MONDAY...INDICATIONS ARE THAT THERE SHOULD STILL BE PLENTY OF
SUN...EVEN IF THERE IS ANY DISSIPATING MORNING CONVECTION OR
AFTERNOON DEVELOPMENT. WITH 925MB TEMPS CLIMBING FURTHER TO AROUND
28C TO POSSIBLY EVEN 30C PER GFS...HIGHS IN THE LOW TO MID 90S ARE
LIKELY. COMBINED WITH DEWPOINTS STAYING ABOUT THE SAME RESULTS IN
PEAK HEAT INDICES OF 100 TO 105.

TUESDAY...WILL HAVE TO WATCH THIS DAY CLOSELY AS IT COULD BE THE
HOTTEST OF THE WEEK. AHEAD OF THE APPROACHING COLD FRONT...A
SOUTHWEST TO WEST WIND PUSH OF THE HOT PLAINS AIR ADVECTS OVER THE
AREA. 925MB TEMPS OF 29-31C PER ECMWF/GFS ARE PROGGED WHICH COULD
PUSH TEMPS TOWARDS 100F. ONLY CONCERN IS THE LOWER SUN ANGLE
COMPARED TO SAY JULY. RAISED HIGHS A COUPLE DEGREES BUT MORE
INCREASES MAY BE NEEDED. NEW FORECAST HIGHS ARE AT RECORDS. HEAT
INDICES AGAIN LOOK TO PEAK OUT AT 100-105.

A COOL DOWN BUT STILL STAYING WELL ABOVE NORMAL IS PROGGED FOR
WEDNESDAY AND THURSDAY. FRIDAY IS A BIT MORE UNCERTAIN WITH THE
24.00Z ECMWF SHOWING ANOTHER SHORTWAVE DROPPING THROUGH THE GREAT
LAKES...SLOWING DOWN THE EASTWARD MOVEMENT OF THE UPPER RIDGE.
FRIDAY PREVIOUSLY LOOKED LIKE WHEN THE HEAT WOULD RETURN. HEAT STILL
ON TARGET TO RETURN DURING LABOR DAY WEEKEND...HOWEVER.

LEANED TOWARDS THE WARM SIDE OF RAW MODEL GUIDANCE FOR LOWS SUNDAY
NIGHT AND MONDAY NIGHT. CONSENSUS OF MODEL GUIDANCE USED THEREAFTER.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 1115 PM CDT FRI AUG 23 2013

A WARM FRONT WILL GRADUALLY LIFT NORTHEAST ACROSS THE REGION
OVERNIGHT/EARLY SAT. NOT A BIG SHIFT IN THE WINDS...AND NOT
MUCH CONVERGENCE AROUND IT. HOWEVER...MESO MODELS POINT TO SOME LOW
LEVEL WARM AIR/ISENTROPIC CONVERGENCE WITH IT...ALTHOUGH NOT A WHOLE
LOT OF SATURATION THROUGH THE COLUMN PER BUFKIT SOUNDINGS. SEE SOME
SCT-BKN CLOUDS...BUT NOT MUCH IN THE WAY OF PCPN AT THIS TIME. THAT
SAID...THE HRRR CONTINUES TO SUGGEST A THIN LINE OF SCT-BKN -SHRA
COULD TRACK ACROSS KLSE NEAR 12Z. CHANCES LOOK A LITTLE BIT BETTER
BY LATE MORNING/AFTERNOON WITH AN INCREASE IN THE LOW LEVEL
CONVERGENCE/WARM AIR ADVECTION. SATURATION STILL NOT
IMPRESSIVE...BUT MIGHT BE ENOUGH FOR SCT SHRA/TS. OVERALL...BEST
SHRA/TS WILL LIKELY HOLD NORTH OF KRST/KLSE THROUGH SAT NIGHT.

HIGH PRESSURE EXITS EAST TONIGHT...WITH A TIGHTENING PRESSURE
GRADIENT WORKING IN OVERNIGHT. SFC WINDS SHOULD NOT LIGHTEN UP TOO
MUCH AS A RESULT...WITH BUFKIT SOUNDINGS INDICATING GOOD STIRRING BY
200 FT. THUS...WINDS WILL BE THE MAIN LIMITING FACTOR TO ANY FOG
POTENTIAL. EXPECT HIGHER GUSTS SAT AFTERNOON AS WINDS BEGIN TO MIX.

&&

.CLIMATE...
ISSUED AT 307 PM CDT FRI AUG 23 2013

HERE ARE SOME RECORD HIGHS FOR LA CROSSE AND ROCHESTER THROUGH LABOR
DAY WEEKEND GIVEN THE UPCOMING INCREASE IN HEAT. FOR MORE CLIMATE
INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON THE HEAT.

          LA CROSSE      ROCHESTER
          ---------      ---------

SUN 8/25   97/1948        97/1948
MON 8/26   96/1991        95/1955
TUE 8/27   95/1973        93/1984
WED 8/28   97/1955        96/1955
THU 8/29   95/1966        92/2012
FRI 8/30   97/2012        96/1941
SAT 8/31   95/1953        93/1960
SUN 9/1    98/1913        94/1937
MON 9/2    98/1937        94/1929

NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.

&&


.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     WIZ017-029-032>034-041>044-053>055-061.

MN...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     MNZ079-086>088-094>096.

IA...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     IAZ008>011-018-019-029-030.

&&

$$

SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
CLIMATE...DAS/AJ






AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 1115 PM CDT FRI AUG 23 2013

.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 307 PM CDT FRI AUG 23 2013

MAIN SHORT TERM CONCERN IS SHOWER/THUNDERSTORM CHANCES.

WATER VAPOR/RAP 500MB ANALYSIS THIS AFTERNOON SHOWING A PERSISTENT
DEEP TROUGHS OF LOW PRESSURE ALONG THE WEST AND EAST COASTS WHILE
AMPLIFYING RIDGE WAS BUDGING SLOWLY FROM THE INTERMOUNTAIN WEST INTO
THE CENTRAL CONUS. AT THE SURFACE...HIGH PRESSURE WAS CENTERED OVER
THE GREAT LAKES REGION. INCREASING SOUTH/SOUTHEAST FLOW WAS NOTED
ACROSS OUR AREA ON THE BACKSIDE OF THE HIGH WITH TEMPERATURES IN THE
UPPER 70S TO LOWER 80S.

CURRENTLY WATCHING WATER VAPOR CLOSELY GIVEN MONSOONAL FLOW TAP INTO
THE INTERMOUNTAIN WEST WITH EMBEDDED SHORTWAVE TROUGH/MCV ACTIVITY.
ONE SUCH WAVE WAS NOTED MOVING OUT OF WY INTO SD AT THIS TIME. THIS
WAVE IS EXPECTED TO PROPAGATE EASTWARD TO THE AREA LATE TONIGHT INTO
SATURDAY AND INTERACT WITH AN APPROACHING WARM FRONT. ALSO OF NOTE
WILL BE EASTERN PERIPHERY OF INCREASING ISENTROPIC LIFT AND MOISTURE
TRANSPORT IMPINGING ON THE AREA. BOTTOM LINE WILL BE INCREASING
MID-LEVEL CLOUD COVER ALONG WITH ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS MAINLY WEST OF THE MISSISSIPPI RIVER AFTER MIDNIGHT...
AND THEN ACROSS THE REST OF THE AREA SATURDAY. NAM HAS MLCAPE VALUES
IN THE 1000-1500J/KG RANGE ACROSS WESTERN WI INTO SOUTHEAST
MN/NORTHEAST IA WITH 1-6KM BULK SHEAR VALUES IN THE 20-25KT RANGE.
GIVEN THIS FACT...WILL HAVE TO WATCH FOR AN ISOLATED VIGOROUS STORM
WITH HEAVIER DOWNPOUR/SMALL HAIL THREAT. OTHERWISE...LOWS
TONIGHT ARE EXPECTED TO BOTTOM OUT IN THE UPPER 50S TO THE MIDDLE
60S WITH HIGHS SATURDAY IN THE 80-85 DEGREE RANGE.

APPEARS BULK OF SHOWER/THUNDERSTORM ACTIVITY SHOULD PUSH NORTHEAST
OF THE AREA WIT THE PASSAGE OF THE WARM FRONT. HOWEVER...MOISTURE
TRANSPORT VECTORS STILL FOCUS ACROSS PORTION OF THE AREA MAINLY
NORTH OF I-94 THROUGH THE NIGHT. AS SUCH...KEPT A 20-30 PERCENT
PROBABILITY OF SHOWERS/THUNDERSTORMS ACROSS THAT AREA. WITH
INCREASING HUMIDITY AND GETTING INTO THE WARM SECTOR...LOWS SATURDAY
NIGHT EXPECTED TO BOTTOM OUT IN THE UPPER 60S TO LOWER 70S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 PM CDT FRI AUG 23 2013

MAIN TOPIC OF CONCERN THROUGH THE LONG TERM PERIOD WILL BE
INCREASING HEAT WITH BUILDING MID/UPPER LEVEL RIDGE OVER THE CENTRAL
CONUS AND UPPER MISSISSIPPI RIVER VALLEY REGION. HOWEVER...MAY SEE A
COUPLE WEAK TROUGH PASSAGES WITH SHOWER/THUNDERSTORM CHANCES. AS A
RESULT...NOT OVERLY CONFIDENT ON HEAT HAZARD HEADLINE AREA PLACEMENT
AT THIS TIME. IT APPEARS AT THIS TIME...THE HIGHEST LIKELIHOOD FOR
HEAT HAZARD HEADLINES WOULD BE FROM I-94 AND SOUTH...WHICH IS
ENTRENCHED MORE INTO THE RIDGE. AREAS NORTH AND EAST OF THIS WILL BE
SUSCEPTIBLE TO THESE WEAK TROUGH PASSAGES AND POTENTIAL FOR
THUNDERSTORM COMPLEXES ROLLING THROUGH. IT APPEARS HEAT INDEX
CRITERIA FOR HEADLINES //100 DEGREES +// WILL BE MET MONDAY AND
TUESDAY AFTERNOONS AND EARLY EVENINGS. AS A RESULT...WILL PROBABLY
HOLD OFF ON ANY HEAT HEADLINE ISSUANCE FOR NOW.

TEMPERATURE/HEAT DETAILS...

ECMWF AND GFS BEGIN TO HEAT THINGS UP ON SUNDAY. GOOD
MIXING/SOUTHWEST BREEZE WILL COMBINE WITH 925 TEMPERATURES IN THE
27-29C RANGE FOR HIGHS IN THE 90-95F DEGREE RANGE. GOOD MIXING
SHOULD DECREASE HUMIDITY SOMEWHAT WITH HEAT INDICES TOPPING OFF IN
THE 95-100 DEGREE RANGE.

HIGHER HUMIDITY WITH TEMPERATURES TOPPING OFF IN THE LOWER/MIDDLE
90S MONDAY AND TUESDAY WILL PUSH HEAT INDICES INTO THE 100-105
DEGREE RANGE...ESPECIALLY SOUTHWEST OF I-94. THESE DAYS WILL NEED AT
LEAST A HEAT ADVISORY.

WEDNESDAY/THURSDAY/FRIDAY LOOKING A BIT MORE UNCERTAIN WITH THE
23.12Z ECMWF/GFS SHOWING COOLING 925MB TEMPERATURES WITH TROUGH
PASSAGE THROUGH PARTS OF THE AREA/GREAT LAKES REGION. THIS WOULD
KEEP THE AREA BELOW HEAT ADVISORY CRITERIA WITH THE POSSIBLE
EXCEPTION OF NORTHEAST IA INTO FAR SOUTHWEST WI WEDNESDAY AFTERNOON.

MORE HEAT APPEARS TO BE ON THE WAY FOR LABOR DAY WEEKEND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 1115 PM CDT FRI AUG 23 2013

A WARM FRONT WILL GRADUALLY LIFT NORTHEAST ACROSS THE REGION
OVERNIGHT/EARLY SAT. NOT A BIG SHIFT IN THE WINDS...AND NOT
MUCH CONVERGENCE AROUND IT. HOWEVER...MESO MODELS POINT TO SOME LOW
LEVEL WARM AIR/ISENTROPIC CONVERGENCE WITH IT...ALTHOUGH NOT A WHOLE
LOT OF SATURATION THROUGH THE COLUMN PER BUFKIT SOUNDINGS. SEE SOME
SCT-BKN CLOUDS...BUT NOT MUCH IN THE WAY OF PCPN AT THIS TIME. THAT
SAID...THE HRRR CONTINUES TO SUGGEST A THIN LINE OF SCT-BKN -SHRA
COULD TRACK ACROSS KLSE NEAR 12Z. CHANCES LOOK A LITTLE BIT BETTER
BY LATE MORNING/AFTERNOON WITH AN INCREASE IN THE LOW LEVEL
CONVERGENCE/WARM AIR ADVECTION. SATURATION STILL NOT
IMPRESSIVE...BUT MIGHT BE ENOUGH FOR SCT SHRA/TS. OVERALL...BEST
SHRA/TS WILL LIKELY HOLD NORTH OF KRST/KLSE THROUGH SAT NIGHT.

HIGH PRESSURE EXITS EAST TONIGHT...WITH A TIGHTENING PRESSURE
GRADIENT WORKING IN OVERNIGHT. SFC WINDS SHOULD NOT LIGHTEN UP TOO
MUCH AS A RESULT...WITH BUFKIT SOUNDINGS INDICATING GOOD STIRRING BY
200 FT. THUS...WINDS WILL BE THE MAIN LIMITING FACTOR TO ANY FOG
POTENTIAL. EXPECT HIGHER GUSTS SAT AFTERNOON AS WINDS BEGIN TO MIX.

&&

.CLIMATE...
ISSUED AT 307 PM CDT FRI AUG 23 2013

HERE ARE SOME RECORD HIGHS FOR LA CROSSE AND ROCHESTER THROUGH LABOR
DAY WEEKEND GIVEN THE UPCOMING INCREASE IN HEAT. FOR MORE CLIMATE
INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON THE HEAT.

          LA CROSSE      ROCHESTER
          ---------      ---------

SUN 8/25   97/1948        97/1948
MON 8/26   96/1991        95/1955
TUE 8/27   95/1973        93/1984
WED 8/28   97/1955        96/1955
THU 8/29   95/1966        92/2012
FRI 8/30   97/2012        96/1941
SAT 8/31   95/1953        93/1960
SUN 9/1    98/1913        94/1937
MON 9/2    98/1937        94/1929

NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...

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

&&

$$

SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
CLIMATE......DAS/AJ

















AREA FORECAST DISCUSSION...UPDATED

NWS PHOENIX AZ

 510 AM MST SAT AUG 24 2013

.UPDATE...UPDATED AVIATION DISCUSSION...

&&

.SYNOPSIS...
A STORMY PERIOD IS ANTICIPATED THIS WEEKEND ACROSS THE REGION WITH
BELOW NORMAL TEMPERATURES. HEAVY RAIN AND LOCALIZED FLOODING MAY
OCCUR...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA. PRECIPITATION CHANCES DECREASE BY EARLY NEXT WEEK...AND
INCREASED MOISTURE WILL CONTINUE THROUGH THE REMAINDER OF THE
WEEK...ALONG WITH NEAR NORMAL TEMPERATURES.

&&

.DISCUSSION...
TODAY AND SUNDAY...A BATCH OF SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER THE METRO AREA EARLY THIS MORNING. LATEST RUC
IDENTIFIES A PERTURBATION MOVING THROUGH THE SOUTH-CENTRAL ARIZONA
DESERTS WHICH MIGHT ACCOUNT FOR THIS. THERE WAS A GRAVITY WAVE THAT
MOVED THROUGH BUT THAT WAS AT LEAST A FEW HOURS AGO. THE RUC SHOWS
THE PERTURBATION SHIFTING NORTH AFTER 12Z AND THUS STORM ACTIVITY
OVER MARICOPA COUNTY SHOULD WIND DOWN SHORTLY AFTER
SUNRISE...ALREADY QUIET ELSEWHERE IN THE FORECAST AREA. LARGER SCALE
FLOW FEATURES OF NOTE INCLUDE THE EVER-PRESENT TROUGH CENTERED NEAR
THE WEST COAST...A LARGE ANTICYCLONE/RIDGE CENTERED OVER THE
PLAINS...AN INVERTED TROUGH CENTERED NEAR THE CHIHUAHUA/TEXAS
BORDER...AND TROPICAL STORM IVO CENTERED WEST OF CABO SAN LUCAS. THE
MODELS HAVE DIFFERING SOLUTIONS ON HOW THE FLOW FEATURES MENTIONED
ABOVE WILL UNFOLD...PARTICULARLY THE INVERTED TROUGH AND THE BROADER
CYCLONIC CIRCULATION ASSOCIATED WITH IVO. FOR INSTANCE...THE GFS
CONTINUES TO TRACK THE IVO ASSOCIATED CIRCULATION TO THE NORTH
FASTER THAN ECWMF AND ESPECIALLY NAM. BY THAT SAME TOKEN...THE WAVE
ALSO DISSIPATES FASTER. THIS HAS IMPLICATIONS FOR TIMING OF
POPS/PRECIP. THERE ARE ALSO DIFFERENCES ON THE UPPER LEVEL
DIVERGENCE GENERATED BY THE APPROACHING WAVE WHICH ALSO IMPACTS
MODEL PRECIP FORECASTS. THOUGH THE NAM IS SLOWER WITH THE IVO
CIRCULATION...IT BRINGS IN A SMALLER WAVE LATER TODAY WHICH MIGHT BE
REMNANTS OF THE INVERTED TROUGH AND/OR A CONVECTIVELY GENERATED
FEATURE FROM SOUTHERN SONORA. THE NAM THUS PRODUCES A BATCH OF
DYNAMICAL FORCING SOONER THAN THE GFS AND ECWMF. THEY ALL SHOW A
MAJOR INFLUX OF MOISTURE. INTERESTINGLY...THERE ARE SOME
SIMILARITIES IN THE SPATIAL DISTRIBUTION OF THE QPF...INCLUDING
LOCAL WRF AND NMM6KM. MAINLY...FROM TONIGHT THROUGH SUNDAY NIGHT
THERE IS A HIGH QPF SWATH OVER WESTERN MARICOPA COUNTY AND SOUTHWEST
ARIZONA. AND A LESSER SWATH OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. IN BETWEEN IS A LOWER QPF SWATH...INCLUDING THE PHOENIX
METRO AREA. HOWEVER...THERE IS A GREAT DEAL OF VARIABILITY FOR
SOUTHEAST CALIFORNIA. THE GFS HAS ITS HEAVIEST SWATH...FOR OUR
FORECAST AREA...OVER EASTERN RIVERSIDE AND IMPERIAL COUNTIES. MADE
NUMEROUS ADJUSTMENTS TO THE QPF AND POP GRIDS. MODIFIED THE FLASH
FLOOD WATCH TO START IT 6 HOURS EARLIER AND TO EXTEND IT EASTWARD
OVER WESTERN MARICOPA COUNTY. IT SHOULD BE NOTED THAT WE WILL NOT
HAVE A TROPICAL STORM THAT BODILY MOVES INTO THE DESERT SOUTHWEST.
RATHER...TROPICAL MOISTURE WILL BE PUSHED NORTHWARD INTO THE REGION
AND THERE WILL BE FLOW FEATURES AIDING THE PRECIPITATION PRODUCTION.
ALSO...WHILE THE WATCH DOES NOT START UNTIL 06Z...THERE WILL LIKELY
BE SOME POTENT THUNDERSTORMS DEVELOPING WITHIN OUR AREA PRIOR TO
THAT. THE GFS...NAM...AND SREF ALL HAVE CAPE VALUES WELL IN EXCESS
OF 1000 J/KG...MAINLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. PRIOR TO THE ARRIVAL OF BROADER SCALE LIFT...ANTICIPATE
STORMS BEING MORE SCATTERED IN NATURE AS OPPOSED TO WIDESPREAD RAIN.
WITH HIGH CAPE VALUES...THERE WILL BE SEVERE POTENTIAL LATE THIS
AFTERNOON AND EVENING. THEREAFTER...ANTICIPATE DECREASING CAPE BUT
MORE WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS. WITH THE CLOUDS
AND RAIN COOLED AIR AROUND...SUNDAY TEMPS WILL BE WELL BELOW NORMAL.

EXTENDED PERIOD...UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND
CONSEQUENTLY I THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM
COVERAGE MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT
FRIDAY WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL
TEMPS GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE
GFS AND EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES
NEXT WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY
PER GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN
PLACE...TUESDAY AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF
THESE TROUGHS ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO
NEED TO BE LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...INCLUDING KPHX...KIWA...KSDL...
CONDITIONS SHOULD REMAIN QUIET FOR THE REST OF THE MORNING HOURS AT
ALL PHOENIX SITES...BUT WILL DETERIORATE QUICKLY THIS AFTERNOON.
SHOWERS AND THUNDERSTORMS APPEAR POSSIBLE AS EARLY AS 21Z AND SHOULD
SWEEP THROUGH THE METRO FROM SOUTHEAST TO NORTHWEST AROUND 00Z.
TIMING DIFFICULT TO PIN DOWN AT THIS POINT...BUT EXPECT GUSTY WINDS
TO 30KTS AND PERIODS OF HEAVY RAIN WITH THE STRONGEST STORMS.
SHOWERS LIKELY TO CONTINUE THROUGH THE EVENING AND OVERNIGHT HOURS.

SOUTHEAST CALIFORNIA...INCLUDING KIPL...AND KBLH...
QUIET WEATHER EXPECTED FOR MOST OF THE DAY...WITH STORMS MOVING IN
FROM THE EAST AROUND 06Z. STRONGEST STORMS WILL BE CAPABLE OF 30+KT
WINDS AND HEAVY RAIN...BUT PINNING DOWN EXACT TIMING DIFFICULT AT
THIS POINT. SHOWERS LIKELY TO CONTINUE THROUGH THE END OF THE TAF
PERIOD.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING AZZ020-021-022-025-026-027.

CA...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING CAZ030>033.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...AJ/DEWEY
AVIATION...LEINS
FIRE WEATHER...AJ






AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 445 AM MST SAT AUG 24 2013

.SYNOPSIS...
A STORMY PERIOD IS ANTICIPATED THIS WEEKEND ACROSS THE REGION WITH
BELOW NORMAL TEMPERATURES. HEAVY RAIN AND LOCALIZED FLOODING MAY
OCCUR...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA. PRECIPITATION CHANCES DECREASE BY EARLY NEXT WEEK...AND
INCREASED MOISTURE WILL CONTINUE THROUGH THE REMAINDER OF THE
WEEK...ALONG WITH NEAR NORMAL TEMPERATURES.

&&

.DISCUSSION...
TODAY AND SUNDAY...A BATCH OF SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER THE METRO AREA EARLY THIS MORNING. LATEST RUC
IDENTIFIES A PERTURBATION MOVING THROUGH THE SOUTH-CENTRAL ARIZONA
DESERTS WHICH MIGHT ACCOUNT FOR THIS. THERE WAS A GRAVITY WAVE THAT
MOVED THROUGH BUT THAT WAS AT LEAST A FEW HOURS AGO. THE RUC SHOWS
THE PERTURBATION SHIFTING NORTH AFTER 12Z AND THUS STORM ACTIVITY
OVER MARICOPA COUNTY SHOULD WIND DOWN SHORTLY AFTER
SUNRISE...ALREADY QUIET ELSEWHERE IN THE FORECAST AREA. LARGER SCALE
FLOW FEATURES OF NOTE INCLUDE THE EVER-PRESENT TROUGH CENTERED NEAR
THE WEST COAST...A LARGE ANTICYCLONE/RIDGE CENTERED OVER THE
PLAINS...AN INVERTED TROUGH CENTERED NEAR THE CHIHUAHUA/TEXAS
BORDER...AND TROPICAL STORM IVO CENTERED WEST OF CABO SAN LUCAS. THE
MODELS HAVE DIFFERING SOLUTIONS ON HOW THE FLOW FEATURES MENTIONED
ABOVE WILL UNFOLD...PARTICULARLY THE INVERTED TROUGH AND THE BROADER
CYCLONIC CIRCULATION ASSOCIATED WITH IVO. FOR INSTANCE...THE GFS
CONTINUES TO TRACK THE IVO ASSOCIATED CIRCULATION TO THE NORTH
FASTER THAN ECWMF AND ESPECIALLY NAM. BY THAT SAME TOKEN...THE WAVE
ALSO DISSIPATES FASTER. THIS HAS IMPLICATIONS FOR TIMING OF
POPS/PRECIP. THERE ARE ALSO DIFFERENCES ON THE UPPER LEVEL
DIVERGENCE GENERATED BY THE APPROACHING WAVE WHICH ALSO IMPACTS
MODEL PRECIP FORECASTS. THOUGH THE NAM IS SLOWER WITH THE IVO
CIRCULATION...IT BRINGS IN A SMALLER WAVE LATER TODAY WHICH MIGHT BE
REMNANTS OF THE INVERTED TROUGH AND/OR A CONVECTIVELY GENERATED
FEATURE FROM SOUTHERN SONORA. THE NAM THUS PRODUCES A BATCH OF
DYNAMICAL FORCING SOONER THAN THE GFS AND ECWMF. THEY ALL SHOW A
MAJOR INFLUX OF MOISTURE. INTERESTINGLY...THERE ARE SOME
SIMILARITIES IN THE SPATIAL DISTRIBUTION OF THE QPF...INCLUDING
LOCAL WRF AND NMM6KM. MAINLY...FROM TONIGHT THROUGH SUNDAY NIGHT
THERE IS A HIGH QPF SWATH OVER WESTERN MARICOPA COUNTY AND SOUTHWEST
ARIZONA. AND A LESSER SWATH OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. IN BETWEEN IS A LOWER QPF SWATH...INCLUDING THE PHOENIX
METRO AREA. HOWEVER...THERE IS A GREAT DEAL OF VARIABILITY FOR
SOUTHEAST CALIFORNIA. THE GFS HAS ITS HEAVIEST SWATH...FOR OUR
FORECAST AREA...OVER EASTERN RIVERSIDE AND IMPERIAL COUNTIES. MADE
NUMEROUS ADJUSTMENTS TO THE QPF AND POP GRIDS. MODIFIED THE FLASH
FLOOD WATCH TO START IT 6 HOURS EARLIER AND TO EXTEND IT EASTWARD
OVER WESTERN MARICOPA COUNTY. IT SHOULD BE NOTED THAT WE WILL NOT
HAVE A TROPICAL STORM THAT BODILY MOVES INTO THE DESERT SOUTHWEST.
RATHER...TROPICAL MOISTURE WILL BE PUSHED NORTHWARD INTO THE REGION
AND THERE WILL BE FLOW FEATURES AIDING THE PRECIPITATION PRODUCTION.
ALSO...WHILE THE WATCH DOES NOT START UNTIL 06Z...THERE WILL LIKELY
BE SOME POTENT THUNDERSTORMS DEVELOPING WITHIN OUR AREA PRIOR TO
THAT. THE GFS...NAM...AND SREF ALL HAVE CAPE VALUES WELL IN EXCESS
OF 1000 J/KG...MAINLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. PRIOR TO THE ARRIVAL OF BROADER SCALE LIFT...ANTICIPATE
STORMS BEING MORE SCATTERED IN NATURE AS OPPOSED TO WIDESPREAD RAIN.
WITH HIGH CAPE VALUES...THERE WILL BE SEVERE POTENTIAL LATE THIS
AFTERNOON AND EVENING. THEREAFTER...ANTICIPATE DECREASING CAPE BUT
MORE WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS. WITH THE CLOUDS
AND RAIN COOLED AIR AROUND...SUNDAY TEMPS WILL BE WELL BELOW NORMAL.

EXTENDED PERIOD...UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND
CONSEQUENTLY I THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM
COVERAGE MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT
FRIDAY WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL
TEMPS GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE
GFS AND EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES
NEXT WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY
PER GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN
PLACE...TUESDAY AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF
THESE TROUGHS ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO
NEED TO BE LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...INCLUDING KPHX...KIWA...KSDL...
THUNDERSTORMS HAVE BEEN STRUGGLING WITH OUTFLOWS STALLING SHORT OF
THE TERMINAL SITES. LATEST THINKING IS SFC WINDS MAY BECOME MORE
VARIABLE BEFORE OBTAINING A PREDOMINANT EASTERLY OVERNIGHT DRIFT.
VIRGA AND LIGHT SHOWERS MAY AFFECT CNTRL ARIZONA OVERNIGHT...THOUGH
CONFIDENCE WAS FAR TOO LOW TO INCLUDE IN TAFS. SHOULD THIS
OCCUR...WINDS MAY BECOME NORTHERLY (OR MORE VARIABLE)
BRIEFLY...THOUGH CIGS SHOULD REMAIN AOA 10K FT. THUNDERSTORM AND
OUTFLOW CHANCES DIRECTLY AFFECTING TERMINAL SITES BECOME FAR HIGHER
LATE SATURDAY AFTERNOON/EVENING...BUT CONFIDENCE IS STILL SHORT OF
ADDING A TEMPO/PROB30 GROUP.

SOUTHEAST CALIFORNIA...INCLUDING KIPL...AND KBLH...
TRANQUIL CONDITIONS AND ONLY HIGH CLOUDS WILL AFFECT SERN CALIFORNIA
TERMINALS THROUGH SATURDAY AFTERNOON...WITH WINDS PREDOMINANTLY S/SE
(THOUGH SOME BRIEF PERIOD OF VARIABLE WINDS ARE POSSIBLE).
THUNDERSTORMS AND OUTFLOW MAY MORE DIRECTLY AFFECT AERODROMES LATE
SATURDAY AFTERNOON/EVENING...THOUGH OVERALL CONFIDENCE IN ADDING ANY
MENTION IN THIS TAF PACKAGE IS TOO LOW AT THIS TIME.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING AZZ020-021-022-025-026-027.

CA...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING CAZ030>033.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...AJ/DEWEY
AVIATION...HIRSCH
FIRE WEATHER...AJ







AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

 1055 AM EDT SAT AUG 24 2013

.LATE MORNING UPDATE...
MORNING CONVECTION ALLOWING GUIDANCE MEMBERS CONTINUES TO SHOW AN
AFTERNOON EARLY EVENING PATTERN DOMINATED BY STORMS ALONG AND SOUTH
OF THE I-4 CORRIDOR...WITH MORE SCATTERED IN NATURE ACTIVITY FURTHER
NORTH ACROSS MUCH OF THE NATURE COAST. BASED ON THIS CONTINUING
TREND...HAVE REDUCED POPS BETWEEN 18-00Z FROM THE LIKELY 60%+ RANGE
DOWN TO CHANCE 40-50% TO THE NORTH OF PINELLAS/HILLSBOROUGH. THE I-4
CORRIDOR AND SOUTHWARD WILL RETAIN THE LIKELY RAIN CHANCE FORECAST
AFTER 18Z.

&&

.MID MORNING UPDATE (REST OF THE WEEKEND)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN UPPER LEVEL PATTERN
ACROSS THE CONUS DOMINATED BY A LARGE AND AMPLIFIED LONG WAVE RIDGE
COVERING THE MAJORITY OF THE NATION...AND A DOWNSTREAM TROUGH
EJECTING EASTWARD FROM THE ATLANTIC COAST. OUR FORECAST AREA RESIDES
UNDER A LOCAL WEAKNESS IN THE PATTERN BETWEEN THESE TWO FEATURES. WV
IMAGERY SHOWS PLENTY OF SYNOPTIC SCALE SUBSIDENCE / DRYING ALOFT
EXPANDING SOUTHWARD INTO THE CAROLINAS/GA IN THE WAKE OF THE
DEPARTING TROUGH...HOWEVER THIS INFLUENCE WILL STAY TO THE NORTH OF
FLORIDA TODAY. BY SUNDAY...THERE ARE INDICATIONS THAT SOME
SUPPRESSION...AND CERTAINLY DRIER AIR ALOFT WILL BE TRYING TO
OVERSPREAD OUR NORTHERN NATURE COAST ZONES.

24/12Z KTBW SOUNDING SHOWS A FAIRLY TYPICAL...ALTHOUGH SOMEWHAT
MOIST PROFILE THROUGH THE MAJORITY OF THE TROP. PW VALUES ARE A BIT
ABOVE 2"...AND THE WIND PROFILE CONFIRMS THE WEAK PATTERN ALOFT.
PROFILE SHOWS WINDS GENERALLY LESS THAN 10 KNOTS BELOW 300MB...SO
NOT A LOT OF MOTION UP THERE THIS MORNING UNTIL YOU GET TOWARD THE
VERY TOP OF THE TROP. LAPSE RATES ABOVE 500MB ARE CERTAINLY NOT ALL
THAT IMPRESSIVE...AND ALTHOUGH DON`T REALLY EXPECT THIS TO HOLD BACK
ANY CONVECTIVE COVERAGE LATER TODAY...IT MAY CERTAINLY HOLD BACK THE
POTENTIAL INTENSITY OF THE UPDRAFTS. LOCAL HI-RES CONVECTION
ALLOWING MODELS ALONG WITH THE MOST RECENT RUNS OF THE HRRR SEEM TO
BE PICKING UP ON THIS TREND AND SHOWING MAXIMUM UPDRAFTS BELOW 20
M/S...WHICH HAS BEEN FOUND TO BE GENERALLY A GOOD THRESHOLD FOR
SIGNIFICANT SEVERE POTENTIAL. THE OTHER TREND IN THE MOST RECENT
RUNS OF THESE MODELS IS THAT THEY ALL SEEM TO BE PINGING THE HIGHEST
CONVECTIVE COVERAGE THIS AFTERNOON/EARLY EVENING FROM I-4 SOUTHWARD.
IN FACT...IN MORE AND MORE OF THESE ENSEMBLE MEMBERS...IT IS
ACTUALLY A DRAMATIC INCREASE IN COVERAGE SOUTH OF I-4 COMPARED TO
ACROSS THE NATURE COAST. WILL CONTINUE TO MONITOR THE NEXT 1-2 HRRR
RUNS...AND POTENTIALLY DECREASE POPS OUT OF THE LIKELY RANGE FROM
PASCO/HERNANDO NORTHWARD. THE MOISTURE REALLY IS NOT LACKING OVER
THE NATURE COAST...SO THE EXACT REASONING FOR THIS TREND IS NOT
COMPLETELY CLEAR...AND SO RELUCTANT TO SIGNIFICANTLY REDUCE POPS FOR
THE NORTHERN ZONES JUST YET. HOWEVER...THE IMPRESSIVE AGREEMENT WITH
THE MORNING GUIDANCE RUNS IS HARD TO IGNORE.

THE ONE OTHER TREND SEEN ACROSS THE BOARD IS THE INLAND PROPAGATION
OF THE CONVECTIVE ACTIVITY TO I-75 AND EASTWARD BY EARLY EVENING
FOR THE TAMPA BAY AREA. BASED ON THIS TREND...HAVE LIKELY POPS
THROUGH 21Z...AND THEN DROP RAIN CHANCES BACK TO CHANCE INSIDE OF
I-75 FOR HILLSBOROUGH/PINELLAS/MANATEE. FURTHER SOUTH...NO
DEFINITIVE INLAND MOTION TREND IS EVIDENT AND HAVE KEPT A MORE BROAD
LIKELY RAIN CHANCE THROUGH 00Z.

SUNDAY...FEELING EVEN MORE CONFIDENT THAT POPS WILL NEED TO BE
LOWERED OUT OF THE LIKELY RANGE WITH THE NEXT FORECAST PACKAGE TO
THE NORTH OF PINELLAS/HILLSBOROUGH AS LARGE SCALE SUBSIDENCE AND
DRYING CONTINUE TO MARCH SOUTH INTO NORTHERN FLORIDA. QUITE OFTEN WE
WILL SEE CONVECTIVE DEVELOPMENT ALONG THIS PW/MOISTURE
GRADIENT...AND SO CHANCE POPS ARE PROB STILL REPRESENTATIVE...
HOWEVER LIKELY COVERAGE WOULD SEEM OVERDONE GIVEN THE INCREASING
NEGATIVE INFLUENCES TOWARD RISING MOTION. SOUTHERN HALF OF THE
FORECAST AREA CONTINUES TO RESIDE UNDER A FAVORABLE COLUMN TO
SUPPORT NUMEROUS AFTERNOON/EVENING STORMS.

&&

.AVIATION...
VFR THIS MORNING GIVES WAY TO INCREASING CLOUDS AND SCT TSRA DURING
THE AFTERNOON AND EARLY EVENING. TSRA INITIALLY FORM INLAND THEN
DRIFT BACK ACROSS THE COAST TO THE GULF...WITH MVFR/LCL IFR POSSIBLE.

&&

.MARINE...
NO HEADLINES ARE ANTICIPATED FOR THE NEXT SEVERAL DAYS. EAST TO
SOUTHEAST WINDS WILL REMAIN IN PLACE OVER THE WATERS WITH A SEA
BREEZE DEVELOPING CLOSE TO THE COAST EACH AFTERNOON.

&&

.FIRE WEATHER...
NO CONCERNS OTHER THAN POSSIBLE PATCHY GROUND FOG IN THE NORMAL
FOG-PRONE AREAS AND IN THOSE SPOTS THAT RECEIVE RAINFALL.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  89  75  88  75 /  60  30  60  30
FMY  90  75  88  73 /  60  30  70  30
GIF  91  72  91  72 /  60  50  60  20
SRQ  88  74  89  74 /  60  30  60  30
BKV  88  71  89  70 /  60  40  60  30
SPG  88  77  87  76 /  60  30  60  30

&&

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

&&

$$

UPDATES...MROCZKA
AVIATION...RUDE







AREA FORECAST DISCUSSION

NWS MIAMI FL

 1010 AM EDT SAT AUG 24 2013

.UPDATE...

THE LATEST SATELLITE IMAGERY AND RECENT RADAR RETURNS INDICATE
WIDELY DISPERSED SHOWERS ACROSS THE REGIONAL WATERS AND ACROSS
PORTIONS OF THE SOUTH FLORIDA PENINSULA. THE 12Z SOUNDING
INDICATED A PWAT JUST UNDER TWO INCHES WITH LIGHT EAST TO SOUTHEAST
FLOW IN THE LOW TO MID LEVELS. THIS WIND PROFILE IS SOMEWHAT
FAVORABLE FOR WATERSPOUTS AND RECENT SATELLITE IMAGERY INDICATES
CLOUD CONVERGENCE BANDS ACROSS THE LOCAL ATLANTIC WATERS AND
BISCAYNE BAY AND ALSO ACROSS THE LOCAL GULF WATERS...WITH A CHANCE
OF WATERSPOUTS TODAY. OTHERWISE THE FORECAST IS ON TRACK WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE
PENINSULA BY LATE MORNING WITH MORE NUMEROUS ACTIVITY ACROSS THE
INTERIOR AND WEST AS THE AFTERNOON PROGRESSES. GIVEN THE
AFOREMENTIONED WIND PROFILE THE STORM MOTION WILL BE SLOW TODAY
AND WITH LOCALLY HEAVY RAINFALL POSSIBLE THERE COULD BE ISOLATED
AREAS OF MINOR URBAN TYPE FLOODING MAINLY EXPECTED ACROSS THE
INTERIOR AND WEST THIS AFTERNOON.

60

&&

.PREV DISCUSSION... /ISSUED 827 AM EDT SAT AUG 24 2013/

AVIATION...
THE TAIL END OF AN UPPER LEVEL TROUGH AXIS WILL SLIDE SOUTH INTO
NORTHERN FLORIDA TODAY...AND TOWARDS LAKE OKEECHOBEE BY THE END OF
THE PERIOD. UPPER LEVEL CLOUDS WILL INCREASE TOWARDS 12Z ON SUNDAY
AS THE SOUTHERN END OF THE TROUGH AXIS APPROACHES. THE PRESSURE
GRADIENT IS SLIGHTLY WEAKER...WITH EASTERLY WINDS EXPECTED TO
INCREASE TO AROUND 10 KNOTS FOR THE EAST COAST TAF SITES. KEPT VCSH
FOR THE EAST COAST TAF SITES TODAY. THE THUNDERSTORM THREAT IS
FORECAST TO BE MAINLY OVER THE INTERIOR AND GULF COAST. AT KAPF...A
SEA BREEZE IS FORECAST TO PUSH INLAND BETWEEN 17-18Z. NUMEROUS
SHOWERS AND STORMS ARE FORECAST TO DEVELOP IN THE AFTERNOON...SO
ADDED A TEMPO GROUP FROM 19-23Z. MVFR/IFR CONDITIONS ARE POSSIBLE IN
STORMS. LIGHT WINDS ARE EXPECTED AGAIN OVERNIGHT TONIGHT.

PREV DISCUSSION... /ISSUED 418 AM EDT SAT AUG 24 2013/

SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL IMPACT SOUTH FLORIDA MAINLY FROM
TONIGHT THROUGH EARLY IN THE WEEK...LEADING TO A GRADUAL INCREASE IN
RAIN CHANCES THROUGH THE PERIOD. HIGH PRESSURE BUILDS BACK INTO THE
REGION EARLY TO MIDDLE PART OF THE NEXT WEEK.

SHORT TERM /TODAY THROUGH SUNDAY NIGHT/...
SYNOPTIC PATTERN THIS WEEKEND WILL BE DOMINATED BY H5 TROUGH OVER EASTERN
UNITED STATES WITH ITS AXIS AND ASSOCIATED SHORT WAVE...THOUGH DIFFUSE
BUT SHOWN IN VARYING DEGREES BY BOTH GLOBAL AND MESOSCALE MODELS...REACHING
VICINITY OF SOUTH FLORIDA PARTICULARLY BY SUNDAY WITH ITS INFLUENCE
ACROSS THE AREA INCREASING BEGINNING TODAY. ALONG WITH THIS FEATURE...A
LOW-LEVEL BOUNDARY/DECAYING COLD FRONT WILL SPREAD INTO CENTRAL FLORIDA
TODAY AND COULD REACH SOUTH FLORIDA SUNDAY ALTHOUGH IT IS MOST LIKELY
TO WASH OUT BEFORE THEN BUT ITS LINGERING LEFT OVER WILL HELP ENHANCE
CHANCES OF RAIN. WINDS COULD TURN NORTHEASTERLY SUNDAY WITH THIS SOLUTION...AS
NAM AS WELL AS GFS SUGGEST THE BOUNDARY WILL EITHER PASS THROUGH MOST
OF THE CWA SOMETIME BETWEEN LATE SUNDAY AND MONDAY OR SIMPLY THE WIND
WILL SHIFT FROM THE NORTHEAST AS HIGH BUILDS NORTH OF THE AREA BEHIND
DIFFUSING BOUNDARY.

FOR TODAY...HIGH RESOLUTION LOCAL MODELS ALONG WITH HRRR INDICATE PATTERN
OF LATE MORNING AND EARLY AFTERNOON EAST COAST SHOWERS AND STORMS TRANSITIONING
TO INTERIOR AND WEST COAST AGAIN DURING THE AFTERNOON AND EVENING. STORM
MOTION VECTOR FAVORS INTERIOR AND WEST COAST BUT IS WEAK ENOUGH THAT
SOME ACTIVITY MIGHT LINGER ACROSS EAST COAST ALSO INTO THE AFTERNOON
AND EVENING. FOR SUNDAY CONVERGENCE IN THE VICINITY OF THE AFOREMENTIONED
SURFACE BOUNDARY COULD ENHANCE SHOWERS AND THUNDERSTORMS...BUT EVEN
IF BOUNDARY REMAINS NORTH OF CWA...SCATTERED TO NUMEROUS SHOWERS AND
STORMS CAN BE EXPECTED WITH STORM MOTION VECTORS SUGGESTING ABOUT EQUAL
CHANCES EVERYWHERE. WE ARE BASICALLY TALKING ABOUT AN ENHANCED DIURNAL
CYCLE WITH LINGERING ACTIVITY POSSIBLY EXTENDING INTO SUNDAY NIGHT IN
THE PRESENCE OF UPPER LEVEL S/W.

TEMPERATURES WILL CONTINUE TO BE SLIGHTLY ABOVE NORMAL...PARTICULARLY
DURING THE OVERNIGHTS.

ONSHORE FLOW WILL CONTINUE THROUGH THE WEEKEND ALBEIT WEAKER...PROLONGING
A SLIGHT RISK OF RIP CURRENTS ON ATLANTIC BEACHES. HOWEVER...THIS
THREAT SHOULD BE GRADUALLY DIMINISHING INTO THE WEEKEND.

LONG TERM /MONDAY THROUGH FRIDAY/...
THE PREVIOUS DISCUSSED SURFACE BOUNDARY AND UPPER S/W WILL FURTHER
WEAKEN THROUGH THE FIRST HALF OF THE UPCOMING WEEK BUT NOT WITHOUT
RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND STORMS AGAIN ON MONDAY.
HOWEVER BY THE MIDDLE TO LATTER PART OF THE WEEK AN UPPER LEVEL
TROUGH OFF THE EAST COAST OF THE US WILL RETROGRADE IN
ASSOCIATION WITH HIGH AMPLITUDE WAVE PATTERN. GFS IS MORE
AGGRESSIVE WITH THIS THAN ECMWF BUT THE BOTTOM LINE IS THE AREA
WILL BE BETWEEN A STRONG HIGH PRESSURE RIDGE ACROSS THE MIDDLE OF
THE COUNTRY AND THE TROUGH OF LOW PRESSURE OFF THE EAST COAST OF THE
US. THIS IS ALSO CONSISTENT WITH THE ENSEMBLE FORECASTS. AT LOW
LEVELS AREA WILL BE UNDER THE INFLUENCE OF WEAK RIDGE OF HIGH
PRESSURE JUST TO THE NORTH POSSIBLY PUSHING SOUTH ACROSS THE AREA
BY LATE IN THE WEEK. ALONG WITH THIS MOISTURE LEVELS WILL BE
RUNNING ABOVE NORMAL EARLY IN THE WEEK, AROUND NORMAL MIDDLE TO
LATTER PART OF THE WEEK AND PERHAPS SLIGHTLY ABOVE NORMAL BY LATE IN
THE WEEK.

BOTTOM LINE...AFTER THE START OF THE WEEK ON MONDAY AREA WILL BE
UNDER A WEAK STEERING FLOW ENVIRONMENT WITH ABOUT EQUAL CHANCES
OF SCATTERED SHOWERS AND THUNDERSTORMS EVERYWHERE THROUGH THE PERIOD
ALONG WITH TYPICAL DIURNAL CYCLE AND TEMPERATURES NEAR NORMAL.

MARINE...
OUTSIDE A BRIEF PERIOD OF WINDS OF AROUND 15 KNOTS OFFSHORE THE
SOUTHWEST FLORIDA COAST SUNDAY...WINDS AND WAVES WILL REMAIN BELOW
10 TO 15 KNOTS AND 2 TO 4 FEET RESPECTIVELY THROUGH THE FORECAST
PERIOD SO NO HIGHLIGHTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  90  78  87  76 / 50 30 50 30
FORT LAUDERDALE  89  80  87  77 / 40 20 50 30
MIAMI            90  78  88  77 / 40 20 50 30
NAPLES           91  75  88  74 / 60 40 60 30

&&

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

$$

DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...23/SK






AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

 905 AM EDT SAT AUG 24 2013

.UPDATE (REST OF THE WEEKEND)...
13Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN UPPER LEVEL PATTERN
ACROSS THE CONUS DOMINATED BY A LARGE AND AMPLIFIED LONG WAVE RIDGE
COVERING THE MAJORITY OF THE NATION...AND A DOWNSTREAM TROUGH
EJECTING EASTWARD FROM THE ATLANTIC COAST. OUR FORECAST AREA RESIDES
UNDER A LOCAL WEAKNESS IN THE PATTERN BETWEEN THESE TWO FEATURES. WV
IMAGERY SHOWS PLENTY OF SYNOPTIC SCALE SUBSIDENCE / DRYING ALOFT
EXPANDING SOUTHWARD INTO THE CAROLINAS/GA IN THE WAKE OF THE
DEPARTING TROUGH...HOWEVER THIS INFLUENCE WILL STAY TO THE NORTH OF
FLORIDA TODAY. BY SUNDAY...THERE ARE INDICATIONS THAT SOME
SUPPRESSION...AND CERTAINLY DRIER AIR ALOFT WILL BE TRYING TO
OVERSPREAD OUR NORTHERN NATURE COAST ZONES.

24/12Z KTBW SOUNDING SHOWS A FAIRLY TYPICAL...ALTHOUGH SOMEWHAT
MOIST PROFILE THROUGH THE MAJORITY OF THE TROP. PW VALUES ARE A BIT
ABOVE 2"...AND THE WIND PROFILE CONFIRMS THE WEAK PATTERN ALOFT.
PROFILE SHOWS WINDS GENERALLY LESS THAN 10 KNOTS BELOW 300MB...SO
NOT A LOT OF MOTION UP THERE THIS MORNING UNTIL YOU GET TOWARD THE
VERY TOP OF THE TROP. LAPSE RATES ABOVE 500MB ARE CERTAINLY NOT ALL
THAT IMPRESSIVE...AND ALTHOUGH DON`T REALLY EXPECT THIS TO HOLD BACK
ANY CONVECTIVE COVERAGE LATER TODAY...IT MAY CERTAINLY HOLD BACK THE
POTENTIAL INTENSITY OF THE UPDRAFTS. LOCAL HI-RES CONVECTION
ALLOWING MODELS ALONG WITH THE MOST RECENT RUNS OF THE HRRR SEEM TO
BE PICKING UP ON THIS TREND AND SHOWING MAXIMUM UPDRAFTS BELOW 20
M/S...WHICH HAS BEEN FOUND TO BE GENERALLY A GOOD THRESHOLD FOR
SIGNIFICANT SEVERE POTENTIAL. THE OTHER TREND IN THE MOST RECENT
RUNS OF THESE MODELS IS THAT THEY ALL SEEM TO BE PINGING THE HIGHEST
CONVECTIVE COVERAGE THIS AFTERNOON/EARLY EVENING FROM I-4 SOUTHWARD.
IN FACT...IN MORE AND MORE OF THESE ENSEMBLE MEMBERS...IT IS
ACTUALLY A DRAMATIC INCREASE IN COVERAGE SOUTH OF I-4 COMPARED TO
ACROSS THE NATURE COAST. WILL CONTINUE TO MONITOR THE NEXT 1-2 HRRR
RUNS...AND POTENTIALLY DECREASE POPS OUT OF THE LIKELY RANGE FROM
PASCO/HERNANDO NORTHWARD. THE MOISTURE REALLY IS NOT LACKING OVER
THE NATURE COAST...SO THE EXACT REASONING FOR THIS TREND IS NOT
COMPLETELY CLEAR...AND SO RELUCTANT TO SIGNIFICANTLY REDUCE POPS FOR
THE NORTHERN ZONES JUST YET. HOWEVER...THE IMPRESSIVE AGREEMENT WITH
THE MORNING GUIDANCE RUNS IS HARD TO IGNORE.

THE ONE OTHER TREND SEEN ACROSS THE BOARD IS THE INLAND PROPAGATION
OF THE CONVECTIVE ACTIVITY TO I-75 AND EASTWARD BY EARLY EVENING
FOR THE TAMPA BAY AREA. BASED ON THIS TREND...HAVE LIKELY POPS
THROUGH 21Z...AND THEN DROP RAIN CHANCES BACK TO CHANCE INSIDE OF
I-75 FOR HILLSBOROUGH/PINELLAS/MANATEE. FURTHER SOUTH...NO
DEFINITIVE INLAND MOTION TREND IS EVIDENT AND HAVE KEPT A MORE BROAD
LIKELY RAIN CHANCE THROUGH 00Z.

SUNDAY...FEELING EVEN MORE CONFIDENT THAT POPS WILL NEED TO BE
LOWERED OUT OF THE LIKELY RANGE WITH THE NEXT FORECAST PACKAGE TO
THE NORTH OF PINELLAS/HILLSBOROUGH AS LARGE SCALE SUBSIDENCE AND
DRYING CONTINUE TO MARCH SOUTH INTO NORTHERN FLORIDA. QUITE OFTEN WE
WILL SEE CONVECTIVE DEVELOPMENT ALONG THIS PW/MOISTURE
GRADIENT...AND SO CHANCE POPS ARE PROB STILL REPRESENTATIVE...
HOWEVER LIKELY COVERAGE WOULD SEEM OVERDONE GIVEN THE INCREASING
NEGATIVE INFLUENCES TOWARD RISING MOTION. SOUTHERN HALF OF THE
FORECAST AREA CONTINUES TO RESIDE UNDER A FAVORABLE COLUMN TO
SUPPORT NUMEROUS AFTERNOON/EVENING STORMS.

&&

.AVIATION...
VFR THIS MORNING GIVES WAY TO INCREASING CLOUDS AND SCT TSRA DURING
THE AFTERNOON AND EARLY EVENING. TSRA INITIALLY FORM INLAND THEN
DRIFT BACK ACROSS THE COAST TO THE GULF...WITH MVFR/LCL IFR POSSIBLE.

&&

.MARINE...
NO HEADLINES ARE ANTICIPATED FOR THE NEXT SEVERAL DAYS. EAST TO
SOUTHEAST WINDS WILL REMAIN IN PLACE OVER THE WATERS WITH A SEA
BREEZE DEVELOPING CLOSE TO THE COAST EACH AFTERNOON.

&&

.FIRE WEATHER...
NO CONCERNS OTHER THAN POSSIBLE PATCHY GROUND FOG IN THE NORMAL
FOG-PRONE AREAS AND IN THOSE SPOTS THAT RECEIVE RAINFALL.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  89  75  88  75 /  60  30  60  30
FMY  90  75  88  73 /  60  30  70  30
GIF  91  72  91  72 /  60  50  60  20
SRQ  88  74  89  74 /  60  30  60  30
BKV  88  71  89  70 /  60  40  60  30
SPG  88  77  87  76 /  60  30  60  30

&&

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

&&

$$

UPDATE...MROCZKA
AVIATION...RUDE






AREA FORECAST DISCUSSION

NWS MIAMI FL

 827 AM EDT SAT AUG 24 2013

.AVIATION...
THE TAIL END OF AN UPPER LEVEL TROUGH AXIS WILL SLIDE SOUTH INTO
NORTHERN FLORIDA TODAY...AND TOWARDS LAKE OKEECHOBEE BY THE END OF
THE PERIOD. UPPER LEVEL CLOUDS WILL INCREASE TOWARDS 12Z ON SUNDAY
AS THE SOUTHERN END OF THE TROUGH AXIS APPROACHES. THE PRESSURE
GRADIENT IS SLIGHTLY WEAKER...WITH EASTERLY WINDS EXPECTED TO
INCREASE TO AROUND 10 KNOTS FOR THE EAST COAST TAF SITES. KEPT VCSH
FOR THE EAST COAST TAF SITES TODAY. THE THUNDERSTORM THREAT IS
FORECAST TO BE MAINLY OVER THE INTERIOR AND GULF COAST. AT KAPF...A
SEA BREEZE IS FORECAST TO PUSH INLAND BETWEEN 17-18Z. NUMEROUS
SHOWERS AND STORMS ARE FORECAST TO DEVELOP IN THE AFTERNOON...SO
ADDED A TEMPO GROUP FROM 19-23Z. MVFR/IFR CONDITIONS ARE POSSIBLE IN
STORMS. LIGHT WINDS ARE EXPECTED AGAIN OVERNIGHT TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 418 AM EDT SAT AUG 24 2013/

SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL IMPACT SOUTH FLORIDA MAINLY FROM
TONIGHT THROUGH EARLY IN THE WEEK...LEADING TO A GRADUAL INCREASE IN
RAIN CHANCES THROUGH THE PERIOD. HIGH PRESSURE BUILDS BACK INTO THE
REGION EARLY TO MIDDLE PART OF THE NEXT WEEK.

SHORT TERM /TODAY THROUGH SUNDAY NIGHT/...
SYNOPTIC PATTERN THIS WEEKEND WILL BE DOMINATED BY H5 TROUGH OVER EASTERN
UNITED STATES WITH ITS AXIS AND ASSOCIATED SHORT WAVE...THOUGH DIFFUSE
BUT SHOWN IN VARYING DEGREES BY BOTH GLOBAL AND MESOSCALE MODELS...REACHING
VICINITY OF SOUTH FLORIDA PARTICULARLY BY SUNDAY WITH ITS INFLUENCE
ACROSS THE AREA INCREASING BEGINNING TODAY. ALONG WITH THIS FEATURE...A
LOW-LEVEL BOUNDARY/DECAYING COLD FRONT WILL SPREAD INTO CENTRAL FLORIDA
TODAY AND COULD REACH SOUTH FLORIDA SUNDAY ALTHOUGH IT IS MOST LIKELY
TO WASH OUT BEFORE THEN BUT ITS LINGERING LEFT OVER WILL HELP ENHANCE
CHANCES OF RAIN. WINDS COULD TURN NORTHEASTERLY SUNDAY WITH THIS SOLUTION...AS
NAM AS WELL AS GFS SUGGEST THE BOUNDARY WILL EITHER PASS THROUGH MOST
OF THE CWA SOMETIME BETWEEN LATE SUNDAY AND MONDAY OR SIMPLY THE WIND
WILL SHIFT FROM THE NORTHEAST AS HIGH BUILDS NORTH OF THE AREA BEHIND
DIFFUSING BOUNDARY.

FOR TODAY...HIGH RESOLUTION LOCAL MODELS ALONG WITH HRRR INDICATE PATTERN
OF LATE MORNING AND EARLY AFTERNOON EAST COAST SHOWERS AND STORMS TRANSITIONING
TO INTERIOR AND WEST COAST AGAIN DURING THE AFTERNOON AND EVENING. STORM
MOTION VECTOR FAVORS INTERIOR AND WEST COAST BUT IS WEAK ENOUGH THAT
SOME ACTIVITY MIGHT LINGER ACROSS EAST COAST ALSO INTO THE AFTERNOON
AND EVENING. FOR SUNDAY CONVERGENCE IN THE VICINITY OF THE AFOREMENTIONED
SURFACE BOUNDARY COULD ENHANCE SHOWERS AND THUNDERSTORMS...BUT EVEN
IF BOUNDARY REMAINS NORTH OF CWA...SCATTERED TO NUMEROUS SHOWERS AND
STORMS CAN BE EXPECTED WITH STORM MOTION VECTORS SUGGESTING ABOUT EQUAL
CHANCES EVERYWHERE. WE ARE BASICALLY TALKING ABOUT AN ENHANCED DIURNAL
CYCLE WITH LINGERING ACTIVITY POSSIBLY EXTENDING INTO SUNDAY NIGHT IN
THE PRESENCE OF UPPER LEVEL S/W.

TEMPERATURES WILL CONTINUE TO BE SLIGHTLY ABOVE NORMAL...PARTICULARLY
DURING THE OVERNIGHTS.

ONSHORE FLOW WILL CONTINUE THROUGH THE WEEKEND ALBEIT WEAKER...PROLONGING
A SLIGHT RISK OF RIP CURRENTS ON ATLANTIC BEACHES. HOWEVER...THIS
THREAT SHOULD BE GRADUALLY DIMINISHING INTO THE WEEKEND.

LONG TERM /MONDAY THROUGH FRIDAY/...
THE PREVIOUS DISCUSSED SURFACE BOUNDARY AND UPPER S/W WILL FURTHER
WEAKEN THROUGH THE FIRST HALF OF THE UPCOMING WEEK BUT NOT WITHOUT
RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND STORMS AGAIN ON MONDAY.
HOWEVER BY THE MIDDLE TO LATTER PART OF THE WEEK AN UPPER LEVEL
TROUGH OFF THE EAST COAST OF THE US WILL RETROGRADE IN
ASSOCIATION WITH HIGH AMPLITUDE WAVE PATTERN. GFS IS MORE
AGGRESSIVE WITH THIS THAN ECMWF BUT THE BOTTOM LINE IS THE AREA
WILL BE BETWEEN A STRONG HIGH PRESSURE RIDGE ACROSS THE MIDDLE OF
THE COUNTRY AND THE TROUGH OF LOW PRESSURE OFF THE EAST COAST OF THE
US. THIS IS ALSO CONSISTENT WITH THE ENSEMBLE FORECASTS. AT LOW
LEVELS AREA WILL BE UNDER THE INFLUENCE OF WEAK RIDGE OF HIGH
PRESSURE JUST TO THE NORTH POSSIBLY PUSHING SOUTH ACROSS THE AREA
BY LATE IN THE WEEK. ALONG WITH THIS MOISTURE LEVELS WILL BE
RUNNING ABOVE NORMAL EARLY IN THE WEEK, AROUND NORMAL MIDDLE TO
LATTER PART OF THE WEEK AND PERHAPS SLIGHTLY ABOVE NORMAL BY LATE IN
THE WEEK.

BOTTOM LINE...AFTER THE START OF THE WEEK ON MONDAY AREA WILL BE
UNDER A WEAK STEERING FLOW ENVIRONMENT WITH ABOUT EQUAL CHANCES
OF SCATTERED SHOWERS AND THUNDERSTORMS EVERYWHERE THROUGH THE PERIOD
ALONG WITH TYPICAL DIURNAL CYCLE AND TEMPERATURES NEAR NORMAL.

MARINE...
OUTSIDE A BRIEF PERIOD OF WINDS OF AROUND 15 KNOTS OFFSHORE THE
SOUTHWEST FLORIDA COAST SUNDAY...WINDS AND WAVES WILL REMAIN BELOW
10 TO 15 KNOTS AND 2 TO 4 FEET RESPECTIVELY THROUGH THE FORECAST
PERIOD SO NO HIGHLIGHTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  90  78  87  76 / 50 30 50 30
FORT LAUDERDALE  89  80  87  77 / 40 20 50 30
MIAMI            90  78  88  77 / 40 20 50 30
NAPLES           91  75  88  74 / 60 40 60 30

&&

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

$$

DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...23/SK






AREA FORECAST DISCUSSION

NWS GOODLAND KS

 525 AM MDT SAT AUG 24 2013

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 593DM RIDGE CENTERED
OVER THE CENTRAL CONUS...WITH THE MEAN STORM THRACE WELL NORTH AND
WEST OF THE TRI-STATE REGION.

H5 RIDGE WILL STRENGTHEN TO 595-596DM BY SUN/MON AND REMAIN OVER
KS...KEEPING LARGE SCALE SUBSIDENCE IN PLACE...AND GENERALLY STABLE
CONDITIONS ACROSS THE CWA. STRENGTHENING LEE TROUGH WILL KEEP
BREEZY-WINDY CONDITIONS IN PLACE THROUGH EARLY NEXT WEEK AND STRONG
WAA ACROSS OUR CWA. PRIMARY FORECAST CHALLENGE IS HIGH/LOW TEMPS AND
MARGINAL FIRE WEATHER CONDITIONS.

BASED ON H85 TEMPS NEARING 30-31C EACH AFTERNOON WE SHOULD SEE HIGHS
WELL ABOVE NORMAL IN THE UPPER 90S/NEAR 100F EACH DAY. ONCE THIS
PATTERN IS ESTABLISHED WE SHOULD GET A BETTER HANDLE ON MIXING/H85
BIAS WHICH SHOULD MAKE THINGS A LITTLE EASIER...HOWEVER FOR NOW I
KEPT FORECAST CLOSE TO GUIDANCE. REGARDING LOW TEMPS...WITH
OVERNIGHT WINDS LIKELY REMAINING BREEZING (ESPECIALLY EAST) WE
SHOULDNT SEE AS MUCH COOLING AS MOS GUIDANCE WOULD INDICATE...SO I
TRENDED FORECAST TOWARDS ECMWF 2M GUIDANCE WHICH SEEMS TO BETTER
REFLECT THIS WARMER TREND.

REGARDING FIRE WEATHER...USING A CONSERVATIVE MIXING HEIGHT I HAVE
RH VALUES IN THE UPPER TEENS IN THE WEST THROUGH EARLY NEXT WEEK.
WITH LOWE TD/RH VALUES ALONG AND BEHIND TROUGH AXIS AND STRONGER
WINDS TO THE EAST...I AM NOT CURRENTLY ANTICIPATING MEETING THE 3HR
REQUIREMENT FOR RFW.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

A BROAD UPPER LEVEL RIDGE WILL BE WELL ESTABLISHED BY THE EXTENDED
PERIOD BEGINNING EARLY NEXT WEEK PROVIDING ABOVE NORMAL TEMPS AND
DRY CONDITIONS. IN GENERAL MODEL CONSENSUS HAS BEEN SOLID OVER THE
PAST FEW DAYS FOR THIS PERIOD...WITH THE ONLY REAL UNCERTAINTIES
BEING /1/ MAX TEMPS AND /2/ HOW THE RIDGE WILL EVOLVE LATE IN THE
WEEK.

IT LOOKS LIKE MAX TEMPS WILL PEAK EARLY IN THE WEEK...WITH
850MB TEMPS IN THE LOW 30S C AS THEY HAVE BEEN PROGGED FOR DAYS.
FULL SUNSHINE AND MIXING WILL LEAD TO HIGHS IN THE MID TO UPPER
90S...AND LOWS IN THE MID 60S IN EASTERN COLORADO TO LOW 70S FARTHER
EAST INTO KANSAS.

ADDRESSING THE SECOND POINT...WHILE THE OVERALL
PATTERN HAS BEEN CONSISTENT SOME OF THE FINE DETAILS TOWARDS THE END
OF THE WEEK ARE LOOKING A BIT LESS CERTAIN NOW. WHILE THE ECMWF AND
GEFS WERE MOVING THE RIDGE EAST AT THE END OF THE WEEK IN PAST
RUNS...THE 00Z GUIDANCE FROM GFS/GEFS/ECMWF ARE FAVORING MORE OF A
RETROGRADING RIDGE TO GO FROM CENTERED OVER KANSAS TOWARDS WESTERN
KANSAS. THIS WOULD LEAD TO A LESS FAVORABLE ENVIRONMENT FOR A
SURFACE TROUGH IN EASTERN CO AND ACCOMPANYING DEVELOPMENT OF BREEZY
SURFACE WINDS DURING THE DAY AND A MUCH WEAKER NOCTURNAL LLJ. IF
THIS PATTERN INDEED DEVELOPS THE DRY WEATHER WOULD PROBABLY EXTEND
THROUGH THE END OF THE MONTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 522 AM MDT SAT AUG 24 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK. WITH LEE TROUGH IN EASTERN COLORADO STRENGTHENING
EXPECT WINDS TO INCREASE THROUGH THE TAF PERIOD...WITH SOUTHERLY
WINDS GUSTING TO 30KT AT BOTH TERMINALS THIS AFTERNOON. WHILE
GUSTY WINDS WILL DIMINISH AROUND SUNSET...SUSTAINED WINDS OVER
12KT WILL CONTINUE THROUGH TONIGHT.

&&

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

$$

SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 959 AM CDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 948 AM CDT SAT AUG 24 2013

SEVERAL AREAS OF ELEVATED THUNDERSTORMS FORMING ALONG THE WARM
FRONTAL BOUNDARY ACROSS WESTERN NORTH DAKOTA...AS WELL AS NORTHWEST
NORTH DAKOTA IN THE WARM ADVECTION REGION OF THE LOW. MODEL
FORECAST SOUNDINGS SHOW A WARM MID LEVEL SHOULD INHIBIT STRONG
CONVECTION...SURFACE BASED...THROUGH EARLY AFTERNOON. AREAS OF
THUNDERSTORMS SO FAR HAVE NOT BEEN WELL ORGANIZED...AND BELIEVE
WILL HAVE TO WAIT FOR COLD FRONT`S ARRIVAL LATER THIS AFTERNOON AND
EVENING FOR THE SEVERE POTENTIAL TO KICK IN. CURRENT THINKING IS
THE THUNDERSTORMS ACROSS THE WEST WILL TREND DOWN IN THE SHORT TERM
AS THE DIURNAL LOW LEVEL JET MIXES OUT. THEN WILL WAIT FOR LATE
AFTERNOON POTENTIAL. POOL OF MOIST AIR AND VERY WARM CONDITIONS
WILL PUSH THE HEAT INDEX INTO THE ADVISORY CATEGORY THIS AFTERNOON
SOUTH CENTRAL. CONTINUE THE HEAT ADVISORY. RAISED POPS WEST
CENTRAL AND NORTHWEST WHERE ONGOING CONVECTION IS
CURRENTLY...THEN TRENDED THE POPS BACK DOWN BY NOON.

UPDATE ISSUED AT 640 AM CDT SAT AUG 24 2013

SCATTERED THUNDERSTORMS FROM JUST WEST OF WILLISTON SOUTHEAST TO
NEAR KILLDEER CONTINUE TO TRACK NORTHEAST EARLY THIS MORNING.
UTILIZED THE 10 UTC HRRR FOR GUIDANCE TO EXTRAPOLATE CURRENT
CONVECTION INTO THE NORTH CENTRAL THROUGH THE MORNING HOURS. ALSO
ADJUSTED CLOUD COVER HIGHER IN THIS SAME AREA THROUGH THE MORNING.
OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. STILL
LOOKS TO BE HOT AND HUMID THIS AFTERNOON OVER THE SOUTH CENTRAL
WITH HIGH TEMPERATURES NEAR 100 DEGREES. NO CHANGES TO HEAT
ADVISORY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 242 AM CDT SAT AUG 24 2013

HIGHLIGHTS AND CONCERNS THIS PERIOD DEAL WITH THE DECISION TO
ISSUE A HEAT ADVISORY FOR SOUTH CENTRAL NORTH DAKOTA SATURDAY
AFTERNOON INTO EARLY EVENING...AND POTENTIAL FOR SEVERE WEATHER
LATE THIS AFTERNOON THROUGH THE EVENING HOURS.

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE AND AN ASSOCIATED WARM
FRONT OVER SOUTHEAST MONTANA. LATEST RADAR INDICATES AN AREA OF
SHOWERS AND THUNDERSTORMS IN SOUTHEAST MONTANA ARE MOVING
INTO SOUTHWEST NORTH DAKOTA THIS MORNING. THE 00Z MODEL DATA
SHIFTS THE WARM FRONT THROUGH SOUTH CENTRAL NORTH DAKOTA THIS
AFTERNOON AS LOW PRESSURE MOVES INTO SOUTHERN NORTH DAKOTA. A
COLD FRONT WILL THEN ENTER THE WEST BY MID AFTERNOON. WITH THE
WARM SECTOR OVERHEAD AND H85 TEMPS IN THE +27C TO +29C RANGE...A
WELL MIXED LAYER PER NAM/GFS SOUNDINGS WILL ALLOW FOR HIGH
TEMPERATURES TO REACH AROUND 100 DEGREES ACROSS MOST OF SOUTH
CENTRAL NORTH DAKOTA. THE RELATIVE HUMIDITY CROSS SECTIONS AND WATER
VAPOR LOOP SUGGESTS THAT SCT MID AND HIGH CLOUDS WILL BE THE MAIN
THEME TODAY WITHIN THE WARM SECTOR...AND THUS WENT ABOVE MODEL
GUIDANCE ON HIGH TEMPERATURES. A FEW DAYS AGO H85 TEMPS WERE
+26C WHEN BISMARCK REACHED 102 DEGREES. THINKING THAT TODAY WILL
BE SIMILAR. DEWPOINTS DO BEGIN TO FALL INTO THE LOWER 60S LATER
THIS AFTERNOON FROM BISMARCK TO LINTON...BUT ARE MAINTAINED IN THE
LOWER 70S IN THE JAMES RIVER VALLEY. HEAT INDICES ARE FORECAST TO
RANGE BETWEEN 100 AND 110 DEGREES WHICH COVERS ALL OF SOUTH
CENTRAL NORTH DAKOTA.

IT APPEARS THAT THE GREATEST THREAT FOR SEVERE WEATHER THIS
AFTERNOON AND EVENING WILL RESIDE IN THE WEST AND NORTH AS A
SHORTWAVE NOW LIFTING THROUGH NORTHERN UTAH MOVES INTO THE AREA
LATER TODAY. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREAT. THE MID LEVEL CAP WILL BEGIN TO ERODE BETWEEN 21Z AND 00Z
SUNDAY ACROSS CENTRAL NORTH DAKOTA. THE HIGH RESOLUTION MODELS
CONTINUE TO OFFER DIFFERENT SOLUTIONS ON HOW THINGS WILL EVOLVE
LATER THIS AFTERNOON...SO SOME UNCERTAINTY REMAINS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 242 AM CDT SAT AUG 24 2013

MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.

THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. ENSEMBLE SPREAD IS NEGLIGIBLE
THROUGH ALL BUT THE VERY END OF THE EXTENDED PERIOD AND
DETERMINISTIC LARGE SCALE DIFFERENCES ARE MINIMAL. WITH THAT
SAID...THERE ARE STILL ISSUES AMONG THE DETERMINISTIC MODELS IN
RESOLVING INDIVIDUAL IMPULSES TRANSLATING  THROUGH THE BROAD UPPER
LEVEL FLOW FROM THE WESTERN U.S. INTO THE NORTHERN PLAINS.

THEREFORE THE FORECAST WILL FEATURE HOT DAYTIME HIGHS RANGING FROM
THE MID 80S NORTH TO THE MID 90S SOUTH AND MILD OVERNIGHT LOWS
MAINLY IN THE 60S...WITH A CONTINUED ALMOST DAILY CHANCE OF
THUNDERSTORMS. THERE IS REASONABLE AGREEMENT BETWEEN THE
DETERMINISTIC MODELS THAT MORE POTENT IMPULSES WILL TRAVERSE THE
AREA ON MONDAY AFTERNOON/EVENING AND AGAIN ON WEDNESDAY
AFTERNOON/EVENING. A MODEL BLEND WITH PERSISTENCE PRODUCES HIGHEST
POPS DURING THESE PERIODS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 948 AM CDT SAT AUG 24 2013

AT 9 AM CDT...A WARM FRONT EXTENDED FROM LOW PRESSURE ACROSS
SOUTHERN SASKATCHEWAN INTO WESTERN NORTH DAKOTA. A COLD FRONT
EXTENDED FROM THE LOW ACROSS EASTERN MONTANA. THE WARM AND COLD
FRONTS WILL PROVIDE SEVERAL OPPORTUNITIES AND FOCUSING MECHANISMS
FOR THUNDERSTORMS. THE WARM AND COLD FRONTS WILL MOVE EAST TODAY.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE IMPACTING KMOT-KDIK-
KBIS THROUGH 00Z. TIMING WILL BE CHALLENGING...RADAR EXTRAPOLATION
SUGGEST TSRA TO IMPACT KMOT BETWEEN 16-19Z...THEN KDIK- KBIS-KMOT
AGAIN AFTER 20Z WITH COLD FRONT PASSAGE. MAJORITY OF THUNDERSTORMS
SHOULD MOVE EAST OF THE REGION AFTER 06Z. VFR EXPECTED AT ALL TAF
SITES EXCEPT KJMS...WHERE MVFR COGS IN LOW LEVEL MOISTURE WILL
PREVAIL UNTIL 18Z..THE SHOULD BREAK OUT TO VFR.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 8 PM
CDT /7 PM MDT/ THIS EVENING FOR NDZ019>023-025-034>037-042-
045>048-050-051.

&&

$$

UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 640 AM CDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 640 AM CDT SAT AUG 24 2013

SCATTERED THUNDERSTORMS FROM JUST WEST OF WILLISTON SOUTHEAST TO
NEAR KILLDEER CONTINUE TO TRACK NORTHEAST EARLY THIS MORNING.
UTILIZED THE 10 UTC HRRR FOR GUIDANCE TO EXTRAPOLATE CURRENT
CONVECTION INTO THE NORTH CENTRAL THROUGH THE MORNING HOURS. ALSO
ADJUSTED CLOUD COVER HIGHER IN THIS SAME AREA THROUGH THE MORNING.
OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. STILL
LOOKS TO BE HOT AND HUMID THIS AFTERNOON OVER THE SOUTH CENTRAL
WITH HIGH TEMPERATURES NEAR 100 DEGREES. NO CHANGES TO HEAT
ADVISORY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 242 AM CDT SAT AUG 24 2013

HIGHLIGHTS AND CONCERNS THIS PERIOD DEAL WITH THE DECISION TO
ISSUE A HEAT ADVISORY FOR SOUTH CENTRAL NORTH DAKOTA SATURDAY
AFTERNOON INTO EARLY EVENING...AND POTENTIAL FOR SEVERE WEATHER
LATE THIS AFTERNOON THROUGH THE EVENING HOURS.

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE AND AN ASSOCIATED WARM
FRONT OVER SOUTHEAST MONTANA. LATEST RADAR INDICATES AN AREA OF
SHOWERS AND THUNDERSTORMS IN SOUTHEAST MONTANA ARE MOVING
INTO SOUTHWEST NORTH DAKOTA THIS MORNING. THE 00Z MODEL DATA
SHIFTS THE WARM FRONT THROUGH SOUTH CENTRAL NORTH DAKOTA THIS
AFTERNOON AS LOW PRESSURE MOVES INTO SOUTHERN NORTH DAKOTA. A
COLD FRONT WILL THEN ENTER THE WEST BY MID AFTERNOON. WITH THE
WARM SECTOR OVERHEAD AND H85 TEMPS IN THE +27C TO +29C RANGE...A
WELL MIXED LAYER PER NAM/GFS SOUNDINGS WILL ALLOW FOR HIGH
TEMPERATURES TO REACH AROUND 100 DEGREES ACROSS MOST OF SOUTH
CENTRAL NORTH DAKOTA. THE RELATIVE HUMIDITY CROSS SECTIONS AND WATER
VAPOR LOOP SUGGESTS THAT SCT MID AND HIGH CLOUDS WILL BE THE MAIN
THEME TODAY WITHIN THE WARM SECTOR...AND THUS WENT ABOVE MODEL
GUIDANCE ON HIGH TEMPERATURES. A FEW DAYS AGO H85 TEMPS WERE
+26C WHEN BISMARCK REACHED 102 DEGREES. THINKING THAT TODAY WILL
BE SIMILAR. DEWPOINTS DO BEGIN TO FALL INTO THE LOWER 60S LATER
THIS AFTERNOON FROM BISMARCK TO LINTON...BUT ARE MAINTAINED IN THE
LOWER 70S IN THE JAMES RIVER VALLEY. HEAT INDICES ARE FORECAST TO
RANGE BETWEEN 100 AND 110 DEGREES WHICH COVERS ALL OF SOUTH
CENTRAL NORTH DAKOTA.

IT APPEARS THAT THE GREATEST THREAT FOR SEVERE WEATHER THIS
AFTERNOON AND EVENING WILL RESIDE IN THE WEST AND NORTH AS A
SHORTWAVE NOW LIFTING THROUGH NORTHERN UTAH MOVES INTO THE AREA
LATER TODAY. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREAT. THE MID LEVEL CAP WILL BEGIN TO ERODE BETWEEN 21Z AND 00Z
SUNDAY ACROSS CENTRAL NORTH DAKOTA. THE HIGH RESOLUTION MODELS
CONTINUE TO OFFER DIFFERENT SOLUTIONS ON HOW THINGS WILL EVOLVE
LATER THIS AFTERNOON...SO SOME UNCERTAINTY REMAINS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 242 AM CDT SAT AUG 24 2013

MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.

THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. ENSEMBLE SPREAD IS NEGLIGIBLE
THROUGH ALL BUT THE VERY END OF THE EXTENDED PERIOD AND
DETERMINISTIC LARGE SCALE DIFFERENCES ARE MINIMAL. WITH THAT
SAID...THERE ARE STILL ISSUES AMONG THE DETERMINISTIC MODELS IN
RESOLVING INDIVIDUAL IMPULSES TRANSLATING  THROUGH THE BROAD UPPER
LEVEL FLOW FROM THE WESTERN U.S. INTO THE NORTHERN PLAINS.

THEREFORE THE FORECAST WILL FEATURE HOT DAYTIME HIGHS RANGING FROM
THE MID 80S NORTH TO THE MID 90S SOUTH AND MILD OVERNIGHT LOWS
MAINLY IN THE 60S...WITH A CONTINUED ALMOST DAILY CHANCE OF
THUNDERSTORMS. THERE IS REASONABLE AGREEMENT BETWEEN THE
DETERMINISTIC MODELS THAT MORE POTENT IMPULSES WILL TRAVERSE THE
AREA ON MONDAY AFTERNOON/EVENING AND AGAIN ON WEDNESDAY
AFTERNOON/EVENING. A MODEL BLEND WITH PERSISTENCE PRODUCES HIGHEST
POPS DURING THESE PERIODS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 640 AM CDT SAT AUG 24 2013

THE LATEST RADAR IMAGERY SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS
JUST WEST OF KDIK AND MOVING TOWARD KISN. WILL BEGIN THE FORECAST
WITH LIGHT THUNDERSTORMS AT KISN AND A VCTS AT KDIK. EXPECT THIS
AREA OF PRECIPITATION TO REACH KMOT BY 15Z. KBIS AND KJMS WILL REMAIN
VFR WITH A THREAT OF ISOLATED THUNDERSTORMS AT KBIS BY 00Z SUNDAY.
THERE IS A POTENTIAL FOR SOME SEVERE THUNDERSTORMS TODAY INTO EARLY
TONIGHT WITH LARGE HAIL AND DAMAGING WINDS. PATCHY FOG AND A BRIEF
REDUCTION TO MVFR CIGS/VSBYS IS POSSIBLE AT KJMS THROUGH 15Z
SATURDAY...OTHERWISE EXPECT VFR CIGS/VSBYS.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY FROM 1 PM CDT /NOON MDT/ THIS AFTERNOON TO 8 PM
CDT /7 PM MDT/ THIS EVENING FOR NDZ019>023-025-034>037-042-
045>048-050-051.

&&

$$

UPDATE...TWH
SHORT TERM...KS
LONG TERM...TWH
AVIATION...KS







AREA FORECAST DISCUSSION...UPDATED

NWS MILWAUKEE/SULLIVAN WI

 1057 AM CDT SAT AUG 24 2013

.UPDATE...

LAST FEW RUNS OF HRRR AND WRF4L NOW BRING SOME PRECIPITATION INTO
THE WESTERN CWA...TIED TO THE LINE OF PRECIP CURRENTLY MOVING ACROSS
WESTERN WI. RADAR SHOWS SOME PRECIP FORMING OVER SOUTHWEST WI.
CURRENT ANALYSIS INDICATES SHARP DEW POINT GRADIENT AND LOW LEVEL
MOISTURE ADVECTION ACROSS THE WEST AND SOUNDINGS INDICATE WEAK
INSTABILITY IN THIS AREA THIS AFTERNOON. MAY INTRODUCE LOW POPS FROM
MADISON WESTWARD FOR THIS AFTERNOON IF THIS TREND CONTINUES.

THESE MODELS SHOW A SLIGHT CHANCE OF PRECIP IN WESTERN CWA AFTER
00Z...ASSOCIATED WITH SHORTWAVE AND PRECIP CURRENTLY OVER NW IOWA.

&&

.AVIATION/18Z TAFS/...

VFR CONDITIONS WILL CONTINUE THROUGH THE SUNDAY. THERE IS AN
OUTSIDE CHANCE FOR A SHOWER OR STORM THIS AFTERNOON FOR AREAS WEST
OF MADISON...BUT EXPECTING MOST PLACES TO REMAIN DRY. A VERY WEAK
WAVE MAY KICK OFF A COUPLE SHOWERS OR STORMS THIS EVENING OR
TONIGHT...BUT AGAIN IT LOOKS LIKE MAINLY DRY WEATHER THROUGH THE
DAY SUNDAY. MORE CLOUDS AND LOW LEVEL WIND ARE EXPECTED
TONIGHT THAN THE LAST COUPLE DAYS...SO SHOULD NOT SEE MUCH IN THE
WAY OF FOG.

&&

.PREV DISCUSSION... /ISSUED 355 AM CDT SAT AUG 24 2013/

TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.

UPPER RIDGE BUILDING INTO THE REGION WITH WEAK SHORT WAVE PASSING
WELL NORTH OF FORECAST AREA. HRRR CURRENTLY HAS A BETTER HANDLE
THAN OPERATIONAL MODELS WITH PRECIPITATION OVER ERN
NEBRASKA...THAT WILL TRACK WITH BEST FRONTOGENETIC
FORCING/Q VECTOR CONVERGENCE/ISENTROPIC LIFT SHOWN ON ALL MODELS
TO THE W AND N OF CWA. THUS HAVE REMOVED SLIGHT POPS FROM THE WEST
FOR THIS AFTERNOON AND CHC POPS FOR TONIGHT ACROSS THE FAR NORTH.

925 MB TEMPERATURES WARM ABOUT 2C FROM YESTERDAY SO DECENT MIXING
WILL YIELD HIGHS IN THE MID TO UPPER 80S IN THE WEST...WITH AROUND
80 IN THE EAST AS WINDS OFF OF THE LAKE WILL HOLD READINGS DOWN.

EXPECT ENOUGH GRADIENT WIND AND SUFFICIENT DEW POINT DEPRESSION IN
THE WEST TO NOT HAVE FOG IN FORECAST...EVEN IN THE WISCONSIN RIVER
VALLEY. LIGHTER WINDS EAST MAY ALLOW SOME PATCHY FOG AROUND
SUNRISE.

SUNDAY THROUGH MONDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM.

SHORT TERM MODELS SHOWING 500MB HIGH RETREATING FROM MISSOURI ON
SUNDAY TO KANSAS BY MONDAY NIGHT. THIS ALLOWS FOR WEST NORTHWEST
TO NORTHWEST FLOW AT THIS LEVEL OVER THE WESTERN GREAT LAKES
REGION. AT THE SURFACE...SOUTHWEST LOW LEVEL WINDS BRINGS VERY
WARM AIRMASS INTO THE REGION SUNDAY. AIRMASS IS EXPECTED TO BE
CAPPED.

925MB TEMPERATURES SUGGESTING HIGHS MAINLY AROUND 90 OR IN THE
LOWER 90S. DEW POINTS WILL ALSO BE IN THE LOWER TO MID 60S...WHICH
WILL GIVE HEAT INDEX VALUES IN THE 90 TO 95 RANGE ACROSS THE AREA.

NAM/GFS SHOW 500MB VORTICITY MAXIMUM SLIDING SOUTHEAST ACROSS
NORTHEAST PORTIONS OF THE FORECAST AREA LATER SUNDAY NIGHT.
NAM/GFS HAVE LIGHT QPF WITH THIS FEATURE DURING THIS TIME. ADDED
LOWER END POPS IN THE NORTHERN AND NORTHEASTERN COUNTIES FOR
MAINLY LATER SUNDAY NIGHT. LOWS WILL REMAIN WARM...IN THE LOWER 70S.

GFS/ECMWF/CANADIAN MODELS SHOW WARM FRONT STALLING OUT FROM
CENTRAL MINNESOTA INTO SOUTHEAST WISCONSIN MONDAY INTO MONDAY
NIGHT. THE NAM IS FURTHER SOUTHWEST THAN THE OTHER MODELS WITH THE
FRONTAL POSITION...PERHAPS TOO FAR SOUTHWEST. BEST FORCING FOR
UPWARD VERTICAL MOTION REMAINS WELL NORTHWEST AND NORTH OF THE
AREA DURING THIS TIME.

AREA FORECAST SOUNDINGS ARE SHOWING AMPLE MEAN LAYER CAPE/MODEST
DEEP LAYER SHEAR WITH A WEAK CAP MONDAY...BECOMING MORE ELEVATED
IN NATURE WITH THE CAPE MONDAY NIGHT. KEPT POPS GOING FOR THIS
PERIOD IN THE NORTHEAST HALF OF THE AREA...CLOSEST TO THE LOW
LEVEL FRONTOGENESIS RESPONSE FIELDS.

AREA REMAINS IN WARM SECTOR AIRMASS MONDAY INTO MONDAY NIGHT PER
GFS/ECMWF/CANADIAN MODELS. 925MB TEMPERATURES SUGGEST HIGHS IN THE
LOWER TO PERHAPS MID 90S MONDAY...WITH HEAT INDEX VALUES IN THE
95 TO 101 DEGREE RANGE.

TUESDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS MEDIUM.

GFS/ECMWF SHOW SOME DIFFERENCES WITH TRENDS DURING THIS PERIOD.
THE 500MB HIGH REMAINS OVER THE KANSAS AREA DURING THIS PERIOD.
THE GFS CONTINUES TO BE FURTHER SOUTH WITH THE PASSING LOW
PRESSURE SYSTEM AND FRONTAL BOUNDARY TUESDAY INTO TUESDAY NIGHT.
DECENT MEAN LAYER CAPES OF 1000 TO 1300 J/KG WITH DECENT DEEP
LAYER SHEAR AROUND 30 TO 35 KNOTS ARE SHOWN ON GFS FORECAST
SOUNDINGS. ECMWF IS DRY WITH THE FRONTAL PASSAGE.

BOTH MODELS DO SHOW COLD FRONT DROPPING SOUTHWARD THROUGH THE AREA
TUESDAY NIGHT. CONTINUED POPS FOR TUESDAY AND TUESDAY
NIGHT IN THE NORTHEASTERN HALF OF COUNTIES...CLOSEST TO THE LOW.

AREA REMAINS IN WARM SECTOR AIRMASS ON ECMWF AND GFS...WITH 925MB
TEMPERATURES SUPPORTING ANOTHER DAY OF LOWER TO PERHAPS MID 90S
FOR HIGHS. HEAT INDEX VALUES SHOULD REACH THE 95 TO 101 RANGE
AGAIN. COUNTING WEDNESDAY...THERE WOULD BE THREE DAYS IN A ROW OF
HEAT INDEX VALUES IN THE 95 TO 100 DEGREE RANGE IN SOUTH CENTRAL
WISCONSIN. NEED FOUR IN A ROW FOR A HEAT ADVISORY. IT STILL MAY BE
NEEDED FOR MONDAY AND TUESDAY ACROSS THE AREA...IF DAILY HEAT
INDEX VALUES CONTINUE TO REMAIN AROUND OR ABOVE 100. FOR
NOW...WILL CONTINUE MENTION POTENTIAL IN HAZARDOUS WEATHER
OUTLOOK AND SPECIAL WEATHER STATEMENT.

MODEST COLD AIR ADVECTION AHEAD OF HIGH PRESSURE PUSHES INTO THE
AREA WEDNESDAY ON NORTH TO NORTHEAST WINDS...BRINGING SLIGHTLY
COOLER BUT STILL ABOVE NORMAL TEMPERATURES. HIGH PRESSURE THEN
MOVES SLOWLY SOUTHEAST THROUGH THE REGION THROUGH
THURSDAY...BRINGING QUIET WEATHER AND WARM TEMPERATURES.

WARM AIR ADVECTION AND MOISTURE ADVECTION THEN TRY TO PUSH BACK
INTO PORTIONS OF THE REGION THURSDAY NIGHT INTO FRIDAY...MORE SO
ON ECMWF THAN GFS. USED CONSENSUS POPS FOR NOW IN THIS PERIOD.

AVIATION/12Z TAFS/...ONCE PATCHY MVFR FOG AT KENW AND KUES CLEARS
THIS MORNING...LOOKING AT VFR CONDITIONS THROUGH THE DAY. LIGHT
WINDS OVER THE EAST BRINGS POTENTIAL FOR PATCHY MVFR FOG
REDEVELOPMENT AT KENW TONIGHT...BUT DEW POINT DEPRESSIONS OF 4 TO
6 DEGREES WILL LIKELY PREVENT FORMATION SO WILL LEAVE OUT FOR NOW.

MARINE...STILL LOOKS LIKE BREEZY SOUTHWEST WINDS WILL APPROACH
SMALL CRAFT ADVISORY LEVELS ON SUNDAY...ESPECIALLY CLOSE TO SHORE.
WILL MENTION POTENTIAL IN FORECAST BUT NOT ISSUE A HEADLINE AT
THIS TIME.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&

$$

UPDATE...SM/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
SUNDAY THROUGH FRIDAY...WOOD








AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 645 AM CDT SAT AUG 24 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SAT AUG 24 2013

MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES.

CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING JUST
OFF THE PACIFIC NORTHWEST COAST AND OVER NEW ENGLAND...WHILE STRONG
SUBTROPICAL RIDGING DOMINATED THE CENTRAL AND SOUTHERN PLAINS.
NUMEROUS MONSOONAL SHORTWAVES WERE PRESENT ON THE WEST SIDE OF THE
RIDGE...FROM ARIZONA INTO WYOMING AND SOUTH DAKOTA. SOUTHERLY 850MB
WINDS OF 30-45 KT FROM KANSAS INTO WESTERN MN AHEAD OF THESE
SHORTWAVES ARE TRANSPORTING WARMER AND MORE MOIST AIR INTO THE UPPER
MIDWEST. PRECIPITABLE WATER VALUES HAVE CLIMBED TO 1.5-1.8 INCHES
FROM THE WESTERN PORTION OF THE FORECAST AREA INTO EASTERN PORTIONS
OF SOUTH DAKOTA AND NEBRASKA...PER SATELLITE DERIVED ESTIMATES.
MEANWHILE...850MB TEMPS HAVE CLIMBED TO 16-18C ACROSS THE FORECAST
AREA AND 22-28C ACROSS THE CENTRAL AND NORTHERN PLAINS PER RAP
ANALYSIS. THE GENERAL WARM ADVECTION PATTERN COMBINED WITH DPVA FROM
THE MONSOONAL SHORTWAVES HAS LED TO SOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WYOMING...NEBRASKA AND SOUTH DAKOTA.

SYNOPTIC OVERVIEW...
THE SUBTROPICAL RIDGE OVER THE CENTRAL PLAINS IS PROGGED OVER THE
NEXT 24 HOURS TO BUILD INTO MISSOURI AND STRENGTHEN...CAUSING 500MB
HEIGHTS TO RISE ABOUT 30 METERS OVER THE FORECAST AREA. FOR THE MOST
PART IT APPEARS THE MONSOONAL SHORTWAVES COMING FROM THE ROCKIES
LOOK TO TRACK ACROSS THE DAKOTAS INTO NORTHWEST ONTARIO. THE ONE
SHORTWAVE OVER SOUTH DAKOTA MODELS SHOWED YESTERDAY TO COME ACROSS
THE FORECAST AREA TODAY IS PRETTY MUCH NON-EXISTENT IN MODELS TODAY.
NEVERTHELESS...WITH THE BUILDING RIDGING...THE WARM ADVECTION
PATTERN ACROSS THE UPPER MIDWEST WILL CONTINUE.

DETAILS...
THE QUESTION TODAY IS THE CHANCES OF PRECIPITATION NOW THAT THE
SHORTWAVE FROM SOUTH DAKOTA IS NO LONGER PRESENT. THE SIGNAL FOR
POSSIBLE SHOWER/THUNDERSTORM INITIATION ON THE EASTERN EDGE OF THE
850MB MOISTURE TRANSPORT IS STILL THERE...SUGGESTED BETWEEN 09-15Z
IN THE 24.00Z NAM/REGIONAL CANADIAN AND GFS. AFTER THAT...MODELS
HAVE DEFINITELY TRENDED DRIER FOR THE REST OF THE DAY. THIS MAKES
SENSE WITH THE BUILDING HEIGHTS. NOW THE 24.00Z NAM DOES TRY TO
GENERATE SOME ISOLATED CONVECTION OVER THE NORTHWEST HALF OF THE
AREA LATE IN THE AFTERNOON. HOWEVER...LOOKING AT SOUNDINGS THIS
SEEMS TO BE COMPLETELY TIED TO THE CONVECTIVE SCHEME AND ODD...WITH
MLCIN DROPPING FROM 70-80 J/KG TO 0 J/KG IN 1 HOUR WHILE A SUBSIDENT
PROFILE IS PRESENT. GIVEN THE CONSENSUS FOR A DRY AFTERNOON...WENT
IN THIS DIRECTION. BULK OF THE CONVECTION ALSO LOOKS TO STAY NORTH
OF THE FORECAST AREA TONIGHT WITH THE 850MB MOISTURE TRANSPORT
STREAM MOVING OVERHEAD...WHILE ITS NOSE IS FOCUSED FROM NORTHERN MN
ACROSS LAKE SUPERIOR AND UPPER MI. HAVE SHIFTED CHANCES NORTH TO
ONLY INCLUDE TAYLOR/CLARK NOW...TO ACCOUNT FOR THE DRYING
TREND...AND THESE MIGHT BE ABLE TO BE SHIFTED COMPLETELY OUT OF THE
AREA.

PARTIAL SUNSHINE TODAY COMBINED WITH 925/850MB TEMPS ABOUT 2C WARMER
SHOULD ALLOW HIGHS TO TOP OUT SIMILAR TO OR JUST SLIGHTLY WARMER
COMPARED TO YESTERDAY. CONDITIONS WILL BE A BIT MORE
MUGGY...THOUGH...AS HIGHER DEWPOINTS IN THE UPPER 60S TO LOW 70S
ADVECT IN ON INCREASING SOUTHERLY WINDS. THE SOUTHERLY BREEZE IS
EXPECTED TO PERSIST INTO TONIGHT...ALLOWING THE AFOREMENTIONED
DEWPOINTS TO SPREAD ACROSS THE FORECAST AREA. THE HIGHER DEWPOINTS
AND BREEZE SHOULD HELP KEEP TEMPERATURES UP IN THE MID 60S TO LOW
70S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT AUG 24 2013

HAZARDS...
1. HEAT. CONFIDENCE REMAINS HIGH THAT HEAT INDICES WILL EXCEED
ADVISORY CRITERIA BOTH MONDAY AND TUESDAY. A FEW LOCALIZED SPOTS
COULD EVEN TOUCH EXCESSIVE HEAT WARNING CRITERIA OF 105.
ADDITIONALLY...SUNDAY NOW LOOKS A LITTLE HIGHER FOR HEAT INDICES...
MORE CLOSER TO 100. GIVEN THESE CONDITIONS AS WELL AS WARM OVERNIGHT
LOWS...HAVE ISSUED A HEAT ADVISORY FOR SUNDAY THROUGH TUESDAY.

2. STORMS. THERE ARE PERIODIC STORM CHANCES THROUGHOUT THE LONG TERM
PORTION OF THE FORECAST...PARTICULARLY NORTH/EAST OF I-94.
HOWEVER...0-6KM AND 0-3 KM SHEAR VALUES ARE NEVER THAT IMPRESSIVE...
GENERALLY 25 KT OR LESS. THIS WILL KEEP HEAVY RAIN AS THE MOST
LIKELY HAZARD FROM THE STORMS.

SYNOPTIC OVERVIEW...
THE STRONG SUBTROPICAL RIDGE OVER MISSOURI TO START AT 12Z SUNDAY IS
WELL AGREED UPON BY 24.00Z GUIDANCE TO RETROGRADE WESTWARD THROUGH
THE MIDDLE OF THE WEEK. THIS RETROGRESSION IS CAUSED BY A SERIES OF
SHORTWAVE TROUGHS DROPPING DOWN THE EAST SIDE OF THE RIDGE INTO NEW
ENGLAND...THE MOST IMPRESSIVE OF WHICH CROSSES NEAR THE GREAT LAKES
REGION TUESDAY NIGHT. THE RETROGRESSION DOESNT LAST LONG...
THOUGH...AS A MORE POTENT UPPER TROUGH COMES INTO THE PACIFIC
NORTHWEST LATE IN THE WEEK...HELPING TO PUSH THE RIDGING AND ITS
WARMTH BACK EASTWARD.

PRECIPITATION DETAILS...
SUNDAY CONTINUES TO LOOK DRY WITH ALL SHORTWAVE AND 850MB MOISTURE
TRANSPORT FORCING TRACKING ACROSS LAKE SUPERIOR OR FARTHER NORTH.
THE 24.00Z NAM...HIRES ARW/NMM INITIATES SURFACE BASED CONVECTION
OVER CENTRAL MN LATE SUNDAY AFTERNOON...ALONG A SURFACE TROUGH. THE
CONVECTION THEN DROPS SOUTH TOWARDS I-90 IN THE EVENING. THESE
APPEAR TO BE STRONGLY DRIVEN BY TEMPERATURES REACHING 100F OR SO
ALONG THE TROUGH...WHICH IS THE CONVECTIVE TEMPERATURE. WHETHER OR
NOT THIS HAPPENS IS UNKNOWN...BUT JUST IN CASE DID INCLUDE 20-40
PERCENT CHANCES ALONG/NORTH OF I-90 IN THE EVENING. THESE CHANCES
CONTINUE INTO THE OVERNIGHT HOURS FOR A SECOND SCENARIO...WHERE
CONVECTION FIRES UP IN NORTHWEST WISCONSIN IN THE EVENING AND DROPS
SOUTH FOLLOWING CORFIDI VECTORS. THIS IS PRESENTED BY THE 24.00Z
GFS/ECMWF. IT SHOULD BE NOTED...THOUGH...THE 24.00Z CANADIAN/UKMET
ARE DRY...KEEPING ALL CONVECTION TO THE NORTH OF THE AREA. ALSO
INTERESTING TO NOTE IS THAT THE NAM...GFS AND ECMWF ARE ALL DRY
MONDAY MORNING...SUGGESTING CONVECTION WEAKENS AS IT RUNS INTO THE
CAPPING OVER THE AREA.

ALL MODELS INDICATE THAT AN OUTFLOW BOUNDARY/WARM FRONT SHOULD BE
LOCATED SOUTH OF THE OVERNIGHT CONVECTION...SETTING UP NEAR I-94 FOR
MONDAY AFTERNOON. 24.00Z GFS/ECMWF BOTH FIRE SOME CONVECTION ALONG
THIS BOUNDARY WHICH WOULD APPEAR POSSIBLE GIVEN THE HOT AND HUMID
AIRMASS IMPINGING ON IT FROM THE SOUTHWEST. THEREFORE...CARRIED 20
PERCENT CHANCES ALONG/NORTH OF I-94 FOR THE AFTERNOON. THESE CHANCES
PERSIST THROUGH MONDAY NIGHT AND TUESDAY...AIDED BY INCREASING 850MB
MOISTURE TRANSPORT AHEAD OF A MORE SIGNIFICANT SHORTWAVE TRACKING
ACROSS THE DAKOTAS...INTO NW MINNESOTA AND LAKE SUPERIOR. GREATER
CHANCES FOR CONVECTION MONDAY NIGHT AND TUESDAY SHOULD STAY OFF TO
THE NORTH AND NORTHEAST CLOSER TO THAT SHORTWAVE TRACK.

A COLD FRONT IS PROGGED TO DROP THROUGH TUESDAY NIGHT. PLENTY OF
CAPPING AHEAD OF THE FRONT SHOULD RESTRICT SURFACE BASED CONVECTION
ON IT...WITH DRY CONDITIONS LIKELY IN ITS WAKE FOR WEDNESDAY INTO
THURSDAY. CHANCES OF SHOWERS AND STORMS RETURN THURSDAY NIGHT
THROUGH FRIDAY NIGHT AS THE FRONT GRADUALLY RETURNS BACK
NORTHEASTWARD AS A WARM FRONT.

TEMPERATURE DETAILS...
SUNDAY...WITH PLENTY OF SUN...BREEZY SOUTHWEST WINDS AND 925 MB
TEMPS CLIMBING TO 26-28C...HIGH TEMPS SHOULD EASILY TOP OUT IN THE
UPPER 80S TO LOW 90S. A FEW VALLEY LOCATIONS COULD EVEN HIT THE MID
90S. WITH DEWPOINTS LIKELY IN THE UPPER 60S TO LOW 70S...PEAK HEAT
INDICES OF 95 TO 100 SHOULD BE COMMON...HIGHEST OVER THE NORTHWEST
HALF OF THE FORECAST AREA.

MONDAY...INDICATIONS ARE THAT THERE SHOULD STILL BE PLENTY OF
SUN...EVEN IF THERE IS ANY DISSIPATING MORNING CONVECTION OR
AFTERNOON DEVELOPMENT. WITH 925MB TEMPS CLIMBING FURTHER TO AROUND
28C TO POSSIBLY EVEN 30C PER GFS...HIGHS IN THE LOW TO MID 90S ARE
LIKELY. COMBINED WITH DEWPOINTS STAYING ABOUT THE SAME RESULTS IN
PEAK HEAT INDICES OF 100 TO 105.

TUESDAY...WILL HAVE TO WATCH THIS DAY CLOSELY AS IT COULD BE THE
HOTTEST OF THE WEEK. AHEAD OF THE APPROACHING COLD FRONT...A
SOUTHWEST TO WEST WIND PUSH OF THE HOT PLAINS AIR ADVECTS OVER THE
AREA. 925MB TEMPS OF 29-31C PER ECMWF/GFS ARE PROGGED WHICH COULD
PUSH TEMPS TOWARDS 100F. ONLY CONCERN IS THE LOWER SUN ANGLE
COMPARED TO SAY JULY. RAISED HIGHS A COUPLE DEGREES BUT MORE
INCREASES MAY BE NEEDED. NEW FORECAST HIGHS ARE AT RECORDS. HEAT
INDICES AGAIN LOOK TO PEAK OUT AT 100-105.

A COOL DOWN BUT STILL STAYING WELL ABOVE NORMAL IS PROGGED FOR
WEDNESDAY AND THURSDAY. FRIDAY IS A BIT MORE UNCERTAIN WITH THE
24.00Z ECMWF SHOWING ANOTHER SHORTWAVE DROPPING THROUGH THE GREAT
LAKES...SLOWING DOWN THE EASTWARD MOVEMENT OF THE UPPER RIDGE.
FRIDAY PREVIOUSLY LOOKED LIKE WHEN THE HEAT WOULD RETURN. HEAT STILL
ON TARGET TO RETURN DURING LABOR DAY WEEKEND...HOWEVER.

LEANED TOWARDS THE WARM SIDE OF RAW MODEL GUIDANCE FOR LOWS SUNDAY
NIGHT AND MONDAY NIGHT. CONSENSUS OF MODEL GUIDANCE USED THEREAFTER.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 644 AM CDT SAT AUG 24 2013

AN AREA OF SHOWERS HAS DEVELOPED AT THE NOSE OF SOME 850 TO 700 MB
MOISTURE TRANSPORT. THE MODELS ARE IN GENERAL AGREEMENT THAT THIS
TRANSPORT WILL DISSIPATE AND MOVE NORTH OF THE AREA BY 24.14Z. DUE
TO THIS...ONLY MENTIONED THE SHOWERS AT THE KRST TAF SITE THROUGH
THIS TIME...AND KEPT KLSE DRY. HOWEVER WE WILL HAVE TO WATCH A
THUNDERSTORM COMPLEX OVER SOUTHWEST MINNESOTA AND WESTERN IOWA.
THE RAP SEEMS TO HAVE A DECENT HANDLE ON THIS SYSTEM. IT TRACKS
THIS WEAKENING COMPLEX EAST INTO NORTHEAST IOWA LATE THIS MORNING.
AT THIS TIME...IT LOOKS LIKE THE PRECIPITATION WILL BE SOUTH OF
KRST AND KLSE...SO DID NOT MENTION IT IN THE TAF AT THIS TIME.

A TIGHT PRESSURE GRADIENT BETWEEN THE RETREATING HIGH OVER THE
EAST GREAT LAKES AND AN APPROACHING WARM FRONT WILL KEEP SUSTAINED
WINDS IN THE 10 TO 15 KNOT RANGE WITH WIND GUSTS OF 20 TO 30 KNOTS.
THESE GUSTS WILL RAPIDLY DIMINISH BETWEEN 25.00Z AND 25.03Z WITH
THE LOSS OF DIURNAL HEATING.

FOR TONIGHT...A SCATTERED TO BROKEN 10 TO 15K DECK WILL REMAIN
ACROSS THE AREA.

&&

.CLIMATE...
ISSUED AT 307 PM CDT FRI AUG 23 2013

HERE ARE SOME RECORD HIGHS FOR LA CROSSE AND ROCHESTER THROUGH LABOR
DAY WEEKEND GIVEN THE UPCOMING INCREASE IN HEAT. FOR MORE CLIMATE
INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON THE HEAT.

          LA CROSSE      ROCHESTER
          ---------      ---------

SUN 8/25   97/1948        97/1948
MON 8/26   96/1991        95/1955
TUE 8/27   95/1973        93/1984
WED 8/28   97/1955        96/1955
THU 8/29   95/1966        92/2012
FRI 8/30   97/2012        96/1941
SAT 8/31   95/1953        93/1960
SUN 9/1    98/1913        94/1937
MON 9/2    98/1937        94/1929

NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     WIZ017-029-032>034-041>044-053>055-061.

MN...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     MNZ079-086>088-094>096.

IA...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     IAZ008>011-018-019-029-030.

&&

$$

SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
CLIMATE...DAS/AJ








AREA FORECAST DISCUSSION

NWS PHOENIX AZ

 310 PM MST SAT AUG 24 2013

.SYNOPSIS...
A STORMY PERIOD IS ANTICIPATED THIS WEEKEND ACROSS THE REGION WITH
BELOW NORMAL TEMPERATURES. HEAVY RAIN AND LOCALIZED FLOODING MAY
OCCUR...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA. PRECIPITATION CHANCES DECREASE BY EARLY NEXT WEEK...AND
INCREASED MOISTURE WILL CONTINUE THROUGH THE REMAINDER OF THE
WEEK...ALONG WITH NEAR NORMAL TEMPERATURES.

&&

.DISCUSSION...
WET AND UNSETTLED WEATHER SCENARIO DEVELOPING THIS AFTERNOON PRETTY
MUCH AS EXPECTED...AS MOISTURE FROM TROPICAL SYSTEM IVO CONTINUES TO
SHED TO THE NORTH AND INTO ARIZONA AND SE CALIFORNIA. BEST
MLCAPE/SURFACE BASED CAPE VALUES ARE LOCATED ACROSS SERN CA AND SWRN
AZ. PWAT VALUES ARE UP...WITH PHOENIX REPORTING 1.6 INCHES ON THE
MORNING RAOB. SURFACE DEWPOINTS AT 2 PM RANGED FROM THE MID 5OS TO
MID 60S OVER THE CENTRAL AZ DESERTS...TO THE MID 60S TO LOW 70S OVER
PORTIONS OF IMPERIAL COUNTY. STRONG THUNDERSTORMS HAVE BEEN
DEVELOPING THIS AFTERNOON WEST OF THE LOWER CO RIVER VALLEY WHERE
INSTABILITY IS GREATEST...AND THEY HAVE PRODUCED VERY HEAVY
RAINFALL. RADAR INDICATED OVER 4 INCHES OF RAIN FELL WEST OF THE
SALTON SEA DURING THE EARLY AFTERNOON. STRONG CONVECTION CAN BE
EXPECTED FOR THE REST OF THE AFTERNOON AND INTO THE EVENING HOURS
OVER OUR WESTERN DESERTS.

MLCAPE VALUES ARE MUCH LOWER OVER SOUTH CENTRAL AZ...MOSTLY LESS
THAN 600 J/KG...SO LESS CONVECTION IS EXPECTED. HOWEVER THERE HAS
BEEN QUITE A BIT OF SUNSHINE SOUTH AND EAST OF PHOENIX THIS MORNING
AND EARLY AFTERNOON AND STORMS WILL LIKELY START TO GENERATE AND
MOVE NORTH INTO OUR AREA LATER THIS AFTERNOON AND INTO THE EVENING
HOURS. THUS...WE WILL STILL CALL FOR NEARLY 50 PERCENT CHANCE OF
THUNDERSTORMS TONIGHT OVER OUR EASTERN ZONES. OTHERWISE...FORECASTS
APPEAR ON TRACK AS MOISTURE FROM DECAYING IVO WILL SPREAD INTO THE
CWA LATER TONIGHT...WITH PWAT VALUES MAXING SUNDAY INTO SUNDAY
NIGHT...IN AREAS WEST OF MARICOPA COUNTY. POPS WILL REMAIN ELEVATED
THRU SUNDAY NIGHT...MOSTLY IN THE 60 TO 80 PERCENT BALLPARK. LESS
INSTABILITY EXPECTED SUNDAY/SUNDAY NIGHT SO STORMS WILL BE LESS
SEVERE BUT THE THREAT FOR HEAVY RAIN WILL BE INCREASED DUE TO PWAT
VALUES THAT WILL CLIMB WELL ABOVE 2 INCHES. FLASH FLOOD WATCH WILL
CONTINUE FOR ALL ZONES WEST OF ZONE 23 STARTING AT 11 PM TONIGHT AND
CONTINUING THRU 11 PM SUNDAY NIGHT. LITTLE CHANGE MADE BEYOND SUNDAY
NIGHT...AS MOST OF THE EFFORTS TODAY HAVE BEEN CHASING ONGOING
FLOODING AND SEVERE WEATHER EPISODES. FOLLOWING DISCUSSION IS A MORE
DETAILED ANALYSIS FROM THE MID SHIFT.

PREVIOUS DISCUSSION...A BATCH OF SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER THE METRO AREA EARLY THIS MORNING. LATEST RUC
IDENTIFIES A PERTURBATION MOVING THROUGH THE SOUTH-CENTRAL ARIZONA
DESERTS WHICH MIGHT ACCOUNT FOR THIS. THERE WAS A GRAVITY WAVE THAT
MOVED THROUGH BUT THAT WAS AT LEAST A FEW HOURS AGO. THE RUC SHOWS
THE PERTURBATION SHIFTING NORTH AFTER 12Z AND THUS STORM ACTIVITY
OVER MARICOPA COUNTY SHOULD WIND DOWN SHORTLY AFTER
SUNRISE...ALREADY QUIET ELSEWHERE IN THE FORECAST AREA. LARGER SCALE
FLOW FEATURES OF NOTE INCLUDE THE EVER-PRESENT TROUGH CENTERED NEAR
THE WEST COAST...A LARGE ANTICYCLONE/RIDGE CENTERED OVER THE
PLAINS...AN INVERTED TROUGH CENTERED NEAR THE CHIHUAHUA/TEXAS
BORDER...AND TROPICAL STORM IVO CENTERED WEST OF CABO SAN LUCAS. THE
MODELS HAVE DIFFERING SOLUTIONS ON HOW THE FLOW FEATURES MENTIONED
ABOVE WILL UNFOLD...PARTICULARLY THE INVERTED TROUGH AND THE BROADER
CYCLONIC CIRCULATION ASSOCIATED WITH IVO. FOR INSTANCE...THE GFS
CONTINUES TO TRACK THE IVO ASSOCIATED CIRCULATION TO THE NORTH
FASTER THAN ECWMF AND ESPECIALLY NAM. BY THAT SAME TOKEN...THE WAVE
ALSO DISSIPATES FASTER. THIS HAS IMPLICATIONS FOR TIMING OF
POPS/PRECIP. THERE ARE ALSO DIFFERENCES ON THE UPPER LEVEL
DIVERGENCE GENERATED BY THE APPROACHING WAVE WHICH ALSO IMPACTS
MODEL PRECIP FORECASTS. THOUGH THE NAM IS SLOWER WITH THE IVO
CIRCULATION...IT BRINGS IN A SMALLER WAVE LATER TODAY WHICH MIGHT BE
REMNANTS OF THE INVERTED TROUGH AND/OR A CONVECTIVELY GENERATED
FEATURE FROM SOUTHERN SONORA. THE NAM THUS PRODUCES A BATCH OF
DYNAMICAL FORCING SOONER THAN THE GFS AND ECWMF. THEY ALL SHOW A
MAJOR INFLUX OF MOISTURE. INTERESTINGLY...THERE ARE SOME
SIMILARITIES IN THE SPATIAL DISTRIBUTION OF THE QPF...INCLUDING
LOCAL WRF AND NMM6KM. MAINLY...FROM TONIGHT THROUGH SUNDAY NIGHT
THERE IS A HIGH QPF SWATH OVER WESTERN MARICOPA COUNTY AND SOUTHWEST
ARIZONA. AND A LESSER SWATH OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. IN BETWEEN IS A LOWER QPF SWATH...INCLUDING THE PHOENIX
METRO AREA. HOWEVER...THERE IS A GREAT DEAL OF VARIABILITY FOR
SOUTHEAST CALIFORNIA. THE GFS HAS ITS HEAVIEST SWATH...FOR OUR
FORECAST AREA...OVER EASTERN RIVERSIDE AND IMPERIAL COUNTIES. MADE
NUMEROUS ADJUSTMENTS TO THE QPF AND POP GRIDS. MODIFIED THE FLASH
FLOOD WATCH TO START IT 6 HOURS EARLIER AND TO EXTEND IT EASTWARD
OVER WESTERN MARICOPA COUNTY. IT SHOULD BE NOTED THAT WE WILL NOT
HAVE A TROPICAL STORM THAT BODILY MOVES INTO THE DESERT SOUTHWEST.
RATHER...TROPICAL MOISTURE WILL BE PUSHED NORTHWARD INTO THE REGION
AND THERE WILL BE FLOW FEATURES AIDING THE PRECIPITATION PRODUCTION.
ALSO...WHILE THE WATCH DOES NOT START UNTIL 06Z...THERE WILL LIKELY
BE SOME POTENT THUNDERSTORMS DEVELOPING WITHIN OUR AREA PRIOR TO
THAT. THE GFS...NAM...AND SREF ALL HAVE CAPE VALUES WELL IN EXCESS
OF 1000 J/KG...MAINLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. PRIOR TO THE ARRIVAL OF BROADER SCALE LIFT...ANTICIPATE
STORMS BEING MORE SCATTERED IN NATURE AS OPPOSED TO WIDESPREAD RAIN.
WITH HIGH CAPE VALUES...THERE WILL BE SEVERE POTENTIAL LATE THIS
AFTERNOON AND EVENING. THEREAFTER...ANTICIPATE DECREASING CAPE BUT
MORE WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS. WITH THE CLOUDS
AND RAIN COOLED AIR AROUND...SUNDAY TEMPS WILL BE WELL BELOW NORMAL.

EXTENDED PERIOD...UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND
CONSEQUENTLY I THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM
COVERAGE MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT
FRIDAY WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL
TEMPS GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE
GFS AND EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES
NEXT WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY
PER GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN
PLACE...TUESDAY AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF
THESE TROUGHS ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO
NEED TO BE LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.

&&

.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...WINDS ARE
NOW EXPECTED TO REMAIN PRIMARY OUT OF THE EAST THROUGH THE
EVENING...AND NIGHTTIME HOURS AS OUTFLOWS FROM THUNDERSTORMS MOVE
INTO THE PHOENIX AREA. THESE THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING STRONG GUSTY WINDS AND PERIODS OF HEAVY RAIN AS THEY PASS
THROUGH. LIGHTER SHOWERS AND BKN TO OVC MID-LEVEL CIGS ARE THEN
EXPECTED TO PERSIST THROUGH THE REMAINDER OF THE NIGHT AND INTO
SUNDAY MORNING AS DEEPER MOISTURE MOVES INTO THE REGION.

SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
SHOWERS AND THUNDERSTORM ARE EXPECTED TO IMPACT KIPL THIS
AFTERNOON...AND KBLH EARLY THIS EVENING ARE CONVECTIVE ACTIVITY
BREAKS OUT AS A VERY MOIST AIRMASS BECOMES ENTRENCHED ACROSS THE
REGION. THESE STORMS WILL BE CAPABLE OF PRODUCING STRONG GUSTY WINDS
AND PERIODS OF HEAVY RAIN AS THEY PASS OVER THE TERMINALS. LIKELY
SHOWERS...AND PERHAPS A PERIOD OF STEADY RAIN IS LIKELY LATER
TONIGHT AND ON SUNDAY AS THE AIRMASS STABILIZES OUT...BUT STILL
REMAINS VERY MOIST...WITH BKN TO OVC MID-LEVEL CIGS WIDESPREAD OVER
THE REGION.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
TUESDAY THROUGH SATURDAY...
DEEP SOUTHERLY FLOW IS EXPECTED TO BRING IN ABOVE-AVERAGE AMOUNTS OF
MOISTURE INTO THE REGION THROUGH THE FORECAST PERIOD...WITH ISOLATED
TO SCATTERED THUNDERSTORMS LIKELY EACH AFTERNOON AND EVENING.
MINIMUM HUMIDITY VALUES ARE EXPECTED TO FALL INTO THE 25 TO 35
PERCENT RANGE ACROSS THE LOWER DESERTS...AND INTO THE 35 TO 45
PERCENT RANGE ACROSS THE HIGHER ELEVATIONS EACH DAY...WITH VERY GOOD
TO EXCELLENT OVERNIGHT RECOVERIES. WINDS ARE EXPECTED TO REMAIN ON
THE LIGHT SIDE...EXCEPT NEAR THUNDERSTORMS.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY
     EVENING AZZ020-021-022-025-026-027.

CA...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH SUNDAY
     EVENING CAZ030>033.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...CB
PREVIOUS DISCUSSION...AJ/DEWEY
AVIATION...PERCHA/LEINS
FIRE WEATHER...AJ








AREA FORECAST DISCUSSION...UPDATED

NWS PHOENIX AZ

 910 AM MST SAT AUG 24 2013

.UPDATE...UPDATED AVIATION DISCUSSION...

&&

.SYNOPSIS...
A STORMY PERIOD IS ANTICIPATED THIS WEEKEND ACROSS THE REGION WITH
BELOW NORMAL TEMPERATURES. HEAVY RAIN AND LOCALIZED FLOODING MAY
OCCUR...ESPECIALLY ACROSS SOUTHEAST CALIFORNIA AND SOUTHWEST
ARIZONA. PRECIPITATION CHANCES DECREASE BY EARLY NEXT WEEK...AND
INCREASED MOISTURE WILL CONTINUE THROUGH THE REMAINDER OF THE
WEEK...ALONG WITH NEAR NORMAL TEMPERATURES.

&&

.DISCUSSION...
TODAY AND SUNDAY...A BATCH OF SHOWERS AND THUNDERSTORMS HAVE
DEVELOPED OVER THE METRO AREA EARLY THIS MORNING. LATEST RUC
IDENTIFIES A PERTURBATION MOVING THROUGH THE SOUTH-CENTRAL ARIZONA
DESERTS WHICH MIGHT ACCOUNT FOR THIS. THERE WAS A GRAVITY WAVE THAT
MOVED THROUGH BUT THAT WAS AT LEAST A FEW HOURS AGO. THE RUC SHOWS
THE PERTURBATION SHIFTING NORTH AFTER 12Z AND THUS STORM ACTIVITY
OVER MARICOPA COUNTY SHOULD WIND DOWN SHORTLY AFTER
SUNRISE...ALREADY QUIET ELSEWHERE IN THE FORECAST AREA. LARGER SCALE
FLOW FEATURES OF NOTE INCLUDE THE EVER-PRESENT TROUGH CENTERED NEAR
THE WEST COAST...A LARGE ANTICYCLONE/RIDGE CENTERED OVER THE
PLAINS...AN INVERTED TROUGH CENTERED NEAR THE CHIHUAHUA/TEXAS
BORDER...AND TROPICAL STORM IVO CENTERED WEST OF CABO SAN LUCAS. THE
MODELS HAVE DIFFERING SOLUTIONS ON HOW THE FLOW FEATURES MENTIONED
ABOVE WILL UNFOLD...PARTICULARLY THE INVERTED TROUGH AND THE BROADER
CYCLONIC CIRCULATION ASSOCIATED WITH IVO. FOR INSTANCE...THE GFS
CONTINUES TO TRACK THE IVO ASSOCIATED CIRCULATION TO THE NORTH
FASTER THAN ECWMF AND ESPECIALLY NAM. BY THAT SAME TOKEN...THE WAVE
ALSO DISSIPATES FASTER. THIS HAS IMPLICATIONS FOR TIMING OF
POPS/PRECIP. THERE ARE ALSO DIFFERENCES ON THE UPPER LEVEL
DIVERGENCE GENERATED BY THE APPROACHING WAVE WHICH ALSO IMPACTS
MODEL PRECIP FORECASTS. THOUGH THE NAM IS SLOWER WITH THE IVO
CIRCULATION...IT BRINGS IN A SMALLER WAVE LATER TODAY WHICH MIGHT BE
REMNANTS OF THE INVERTED TROUGH AND/OR A CONVECTIVELY GENERATED
FEATURE FROM SOUTHERN SONORA. THE NAM THUS PRODUCES A BATCH OF
DYNAMICAL FORCING SOONER THAN THE GFS AND ECWMF. THEY ALL SHOW A
MAJOR INFLUX OF MOISTURE. INTERESTINGLY...THERE ARE SOME
SIMILARITIES IN THE SPATIAL DISTRIBUTION OF THE QPF...INCLUDING
LOCAL WRF AND NMM6KM. MAINLY...FROM TONIGHT THROUGH SUNDAY NIGHT
THERE IS A HIGH QPF SWATH OVER WESTERN MARICOPA COUNTY AND SOUTHWEST
ARIZONA. AND A LESSER SWATH OVER THE HIGHER TERRAIN OF SOUTH-CENTRAL
ARIZONA. IN BETWEEN IS A LOWER QPF SWATH...INCLUDING THE PHOENIX
METRO AREA. HOWEVER...THERE IS A GREAT DEAL OF VARIABILITY FOR
SOUTHEAST CALIFORNIA. THE GFS HAS ITS HEAVIEST SWATH...FOR OUR
FORECAST AREA...OVER EASTERN RIVERSIDE AND IMPERIAL COUNTIES. MADE
NUMEROUS ADJUSTMENTS TO THE QPF AND POP GRIDS. MODIFIED THE FLASH
FLOOD WATCH TO START IT 6 HOURS EARLIER AND TO EXTEND IT EASTWARD
OVER WESTERN MARICOPA COUNTY. IT SHOULD BE NOTED THAT WE WILL NOT
HAVE A TROPICAL STORM THAT BODILY MOVES INTO THE DESERT SOUTHWEST.
RATHER...TROPICAL MOISTURE WILL BE PUSHED NORTHWARD INTO THE REGION
AND THERE WILL BE FLOW FEATURES AIDING THE PRECIPITATION PRODUCTION.
ALSO...WHILE THE WATCH DOES NOT START UNTIL 06Z...THERE WILL LIKELY
BE SOME POTENT THUNDERSTORMS DEVELOPING WITHIN OUR AREA PRIOR TO
THAT. THE GFS...NAM...AND SREF ALL HAVE CAPE VALUES WELL IN EXCESS
OF 1000 J/KG...MAINLY OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA. PRIOR TO THE ARRIVAL OF BROADER SCALE LIFT...ANTICIPATE
STORMS BEING MORE SCATTERED IN NATURE AS OPPOSED TO WIDESPREAD RAIN.
WITH HIGH CAPE VALUES...THERE WILL BE SEVERE POTENTIAL LATE THIS
AFTERNOON AND EVENING. THEREAFTER...ANTICIPATE DECREASING CAPE BUT
MORE WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS. WITH THE CLOUDS
AND RAIN COOLED AIR AROUND...SUNDAY TEMPS WILL BE WELL BELOW NORMAL.

EXTENDED PERIOD...UPPER LEVEL SUPPORT WANES SLIGHTLY ON MONDAY AND
CONSEQUENTLY I THINK THERE SHOULD BE AN OVERALL DECREASE IN STORM
COVERAGE MONDAY/MONDAY NIGHT. THE FORECAST FOR TUESDAY THROUGH NEXT
FRIDAY WILL CONSIST OF HIGHER THAN NORMAL POPS AND LOWER THAN NORMAL
TEMPS GIVEN SUBSTANTIALLY HIGHER THAN NORMAL MOISTURE VALUES. THE
GFS AND EUROPEAN MODELS BOTH ADVERTISE A COUPLE OF EASTERLY WAVES
NEXT WEEK...ALTHOUGH EACH MODEL SUGGESTS A DIFFERENT DAY /WEDNESDAY
PER GFS...TUESDAY FOR ECMWF/. WITH SUCH HIGH PWATS IN
PLACE...TUESDAY AND/OR WEDNESDAY COULD BE VERY ACTIVE IF ONE OF
THESE TROUGHS ACTUALLY COME TO PASS AS ADVERTISED. THIS WILL ALSO
NEED TO BE LOOKED INTO FURTHER AS THE EVENT GETS CLOSER.

&&

.AVIATION...
SOUTH-CENTRAL AND SOUTHWEST ARIZONA...INCLUDING KPHX...KIWA...KSDL...
OUTFLOW FROM THUNDERSTORMS OVER NORTHWEST MARICOPA COUNTY COMBINED
WITH THE USUAL DIURNAL TRENDS IS NOW EXPECTED TO KEEP WINDS OUT OF A
WESTERLY DIRECTION AT BOTH KPHX AND KSDL INTO THE AFTERNOON
HOURS...WITH WINDS AT KIWA ALSO BECOMING WESTERLY BY MIDDAY OR EARLY
AFTERNOON. THUNDERSTORMS ARE STILL POSSIBLE BY LATE AFTERNOON OR
EARLY EVENING...WITH GUSTY WINDS AND PERIODS OF HEAVY RAIN WITH THE
STRONGEST STORMS. SHOWERS ARE THEN LIKELY TO CONTINUE THROUGH THE
EVENING AND OVERNIGHT HOURS.

SOUTHEAST CALIFORNIA...INCLUDING KIPL...AND KBLH...
QUIET WEATHER EXPECTED FOR MOST OF THE DAY...WITH STORMS MOVING IN
FROM THE EAST AROUND 06Z. STRONGEST STORMS WILL BE CAPABLE OF 30+KT
WINDS AND HEAVY RAIN...BUT PINNING DOWN EXACT TIMING DIFFICULT AT
THIS POINT. SHOWERS LIKELY TO CONTINUE THROUGH THE END OF THE TAF
PERIOD.

AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.

&&

.FIRE WEATHER...
MONDAY THROUGH FRIDAY...
RATHER HUMID CONDITIONS AND WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED SUNDAY AS TROPICAL MOISTURE OVERSPREADS ARIZONA AND
SOUTHEAST CALIFORNIA. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
AFFECT THE WHOLE FORECAST AREA AT ONE TIME OR ANOTHER SUNDAY INTO
MONDAY. HOWEVER...RAINFALL AMOUNTS WILL BE HIGHLY VARIABLE WITH SOME
LOCATIONS RECEIVING QUITE A BIT LESS THAN OTHERS. ATMOSPHERIC
MOISTURE WILL TREND DOWN MONDAY AND TUESDAY...LEVELING OFF WEDNESDAY
AND THURSDAY. STORM CHANCES WILL ALSO TREND DOWNWARD WHILE
TEMPERATURES TREND UPWARD.


&&

.PSR WATCHES/WARNINGS/ADVISORIES...

AZ...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING AZZ020-021-022-025-026-027.

CA...FLASH FLOOD WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY
     EVENING CAZ030>033.

&&

$$

VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX

DISCUSSION...AJ/DEWEY
AVIATION...PERCHA/LEINS
FIRE WEATHER...AJ






AREA FORECAST DISCUSSION

NWS TAMPA BAY RUSKIN FL

 355 PM EDT SAT AUG 24 2013

.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN UPPER LEVEL PATTERN
ACROSS THE CONUS DOMINATED BY A LARGE AND AMPLIFIED LONG WAVE RIDGE
COVERING THE MAJORITY OF THE NATION...AND A DOWNSTREAM TROUGH
EJECTING EASTWARD FROM THE ATLANTIC COAST. OUR FORECAST AREA RESIDES
UNDER A LOCAL WEAKNESS IN THE PATTERN BETWEEN THESE TWO FEATURES. WV
IMAGERY SHOWS PLENTY OF SYNOPTIC SCALE SUBSIDENCE / DRYING ALOFT
EXPANDING SOUTHWARD INTO THE CAROLINAS/GA IN THE WAKE OF THE
DEPARTING TROUGH...HOWEVER THIS INFLUENCE WILL STAY TO THE NORTH OF
FLORIDA THE REST OF TODAY AND TONIGHT. BY SUNDAY...THERE ARE
INDICATIONS THAT SOME SUPPRESSION...AND CERTAINLY DRIER AIR ALOFT
WILL BE TRYING TO OVERSPREAD OUR NORTHERN NATURE COAST ZONES.

RADAR IS BECOMING ACTIVE THIS MID-AFTERNOON WITH THE MAJORITY OF THE
SCATTERED ACTIVITY TO THE NORTH OF TAMPA BAY. HOWEVER...THE SETUP
APPEARS VERY FAVORABLE FOR SIGNIFICANT THUNDERSTORM DEVELOPMENT
SOUTH OF I-4 ALONG THE SUNCOAST LATE AFTERNOON AND ESPECIALLY EARLY
THIS EVENING. A WELL DEFINED WEST COAST SEA-BREEZE APPEARS TO HAVE
BECOME ESTABLISHED...AND THE EAST COAST SEA-BREEZE IS RAPIDLY
CROSSING THE STATE WITHIN THE WEAK SYNOPTIC FLOW. LATEST HRRR RUNS
HAVE INITIALIZED THIS WELL AND SHOW PLENTY OF CONVECTIVE COVERAGE
ALONG THE I-75 CORRIDOR SOUTH OF TAMPA BAY BEFORE THE DAY IS OUT. A
BIT SURPRISED AT JUST HOW SLOW ACTIVITY HAS BEEN TO GET GOING SOUTH
OF TAMPA BAY...WHERE THE MOST FAVORABLE CONDITIONS APPEAR...BUT
STILL FEEL IT IS JUST A MATTER OF TIME.

&&

.SHORT TERM (THIS EVENING THROUGH MONDAY NIGHT)...
TONIGHT...SCATTERED TO NUMEROUS STORMS WILL BE AROUND WELL INTO THE
EVENING HOURS IF THE LATEST HRRR AND LOCAL WRFARW RUNS ARE "IN THE
BALLPARK" WITH THEIR FORECASTS. LATEST GRIDS SHOW THE HIGH RAIN
CHANCES FOR THE NEXT SEVERAL HOURS...AND THEN SLOWLY DIMINISH THE
THREAT LATE EVENING AND INTO THE EARLY MORNING HOURS. WITH A SURFACE
BOUNDARY SINKING SOUTH AND ABUNDANT COLUMN MOISTURE...IT SHOULD
REMAIN ACTIVE AND EVEN GET MORE ACTIVE IN TERMS OF THUNDERSTORMS
OVER THE COASTAL WATERS TONIGHT INTO SUNDAY MORNING.

SUNDAY...SOME LARGE SCALE SUBSIDENCE AND DRYING WILL CONTINUE TO
MARCH SOUTH INTO NORTHERN FLORIDA. QUITE OFTEN WE WILL SEE
CONVECTIVE DEVELOPMENT ALONG THIS PW/MOISTURE GRADIENT...AND SO
CHANCE POPS ARE PROB STILL REPRESENTATIVE...EVEN AS FAR NORTH AS
LEVY COUNTY. HOWEVER...LIKELY COVERAGE WOULD SEEM OVERDONE GIVEN THE
INCREASING NEGATIVE INFLUENCES TOWARD RISING MOTION. SOUTHERN HALF
OF THE FORECAST AREA CONTINUES TO RESIDE UNDER A FAVORABLE COLUMN TO
SUPPORT NUMEROUS AFTERNOON/EVENING STORMS.

MONDAY...A COUPLE OF FEATURES SUGGEST EVEN LOWER RAIN CHANCES
REGION-WIDE FOR MONDAY AFTERNOON/EVENING...HOWEVER GLOBAL GUIDANCE
IS NOT IN COMPLETE AGREEMENT ON THE DETAILS OF THESE FEATURES GIVING
THE FORECAST A SLIGHTLY LOWER THEN AVERAGE CONFIDENCE. SOMEWHAT
DRIER AIR WILL CONTINUE TO TRY AND WORK SOUTH INTO NORTH FLORIDA
HOLDING BACK THE OVERALL COVERAGE FOR THE NATURE COAST. FURTHER
SOUTH...THE GFS IS NOW QUITE AGGRESSIVE WITH THE FORMATION OF AN
UPPER LOW / CONVECTIVE VORT OFF THE SOUTHWEST FLORIDA COAST THAT
THEN MIGRATES WESTWARD WITH TIME. THIS VORTICITY WOULD LIKELY BE
ACCOMPANIED BY A LARGE CONVECTIVE "BLOB" OVER THE EASTERN GULF OF
MEXICO WHICH CAN HAVE THE INFLUENCE OF AIDING SUPPRESSION /
MID-LEVEL WARMING ON ITS FRIDGES. THE ECMWF DOES HINT AT THIS
FEATURE BUT IS MUCH WEAKER. WILL NOT LEAN MUCH IN EITHER DIRECTION
QUITE YET. KEEPING CHANCE POPS IN THE FORECAST...WITH HIGHEST RAIN
CHANCES STILL SOUTH OF TAMPA BAY...BUT WILL KEEP LIKELY / NUMEROUS
WORDING OUT OF THE FORECAST.

&&

.LONG TERM (TUESDAY-SATURDAY)...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT SHOWING HIGH PRESSURE
REMAINING NORTH OF THE STATE THROUGH MIDWEEK...THEN SLIPPING
SOUTHWARD THROUGH THE PENINSULA FOR THE END OF THE WEEK INTO THE
UPCOMING WEEKEND. STILL NOT SEEING ANY SIGNIFICANT WEATHER FEATURES
TO SPEAK OF THROUGH THE LONG TERM PERIODS...WITH TYPICAL SUMMERTIME
WEATHER CHARACTERIZED BY MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS EXPECTED EACH DAY. TEMPERATURES WILL REMAIN CLOSE TO
CLIMO THROUGH THE LONG TERM PERIODS.

&&

.AVIATION...
VCNTY TSRA UNDER VFR BKN CIGS INTO THIS EVENING...WITH TEMPO MVFR
TSRA IN A 20Z-23Z WINDOW. CAN/T RULE OUT LCL IFR BUT WILL LEAVE OUT
OF TAFS FOR NOW. LIGHT VARIABLE WINDS BUT SOME SEA BREEZE INFLUENCE
TPA/PIE AND PSBL SRQ. VFR OVERNIGHT INTO SUN MORNING WITH VCNTY SHRA
TPA/PIE/LAL STARTING 15Z.

&&

.MARINE...
A STRONG RIDGE OF HIGH PRESSURE WELL TO OUR NORTH ALONG THE
MID-ATLANTIC STATES WILL PROVIDE A GENERALLY EAST TO WEST FLOW
THROUGH THE EARLY PORTION OF THE WEEK. THE GRADIENT IS EXPECTED TO
RELAX ENOUGH SUNDAY AFTERNOON TO PROVIDE FOR AN ONSHORE SEA-BREEZE
TO DEVELOP DURING THE AFTERNOON. THE RIDGE TO OUR NORTH WILL TAKE A
POSITION BY SUNDAY AND MONDAY NIGHTS TO PROVIDE SOME ENHANCED
EASTERLY FLOW EACH NIGHT INTO THE EARLY MORNING HOURS. WINDS MAY AT
TIMES APPROACH CAUTIONARY LEVELS...ESPECIALLY TO THE NORTH OF TARPON
SPRINGS.

&&

.FIRE WEATHER...
A RIDGE OF HIGH PRESSURE WILL KEEP A GENERAL EASTERLY FLOW IN PLACE
INTO THE EARLY PORTION OF THE WEEK. LOCALLY ONSHORE FLOW IS EXPECTED
FOR A TIME SUNDAY AFTERNOON NEAR THE COAST WITH SEA-BREEZE
DEVELOPMENT. A WEAK FRONT WILL DIP INTO NORTH FLORIDA AND WASH OUT
WITH TIME...BUT IS NOT EXPECTED TO PROVIDE ANY SIGNIFICANT DRYING OF
THE PATTERN TO THE LOCAL REGION. NUMEROUS AFTERNOON AND EVENING
THUNDERSTORMS LATE SATURDAY AND AGAIN ON SUNDAY WILL BECOME MORE
SCATTERED IN NATURE BY MONDAY AND TUESDAY. RELATIVE HUMIDITY VALUES
ARE FORECAST TO REMAIN WELL ABOVE CRITICAL LEVELS THROUGH
TUESDAY...AND NO SIGNIFICANT FIRE WEATHER CONCERNS ARE ANTICIPATED.

FOG POTENTIAL...PATCHY GROUND FOG IS POSSIBLE JUST BEFORE AND AROUND
SUNRISE EACH DAY...ESPECIALLY IN AREAS THAT RECEIVE LATE DAY OR
EVENING RAINS.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  75  88  74  89 /  50  60  40  40
FMY  74  90  73  88 /  50  70  40  50
GIF  73  89  72  91 /  50  60  30  40
SRQ  75  88  74  89 /  50  60  40  40
BKV  72  89  71  90 /  50  60  40  30
SPG  77  89  77  88 /  50  60  40  40

&&

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

&&

$$

SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION...RUDE
LONG TERM...JELSEMA






AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1255 PM MDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1051 AM MDT SAT AUG 24 2013

SOUTH WINDS HAVE INCREASED THROUGH THE MORNING. LATEST HRRR/NAM RUN
SHOWS 850 MB WINDS PEAK UNTIL NOON THEN DECLINE UNTIL LATE
AFTERNOON. AM NOT COMPLETELY CONVINCED THE RELATIVE HUMIDITIES
WILL FALL ENOUGH/WINDS BE GUSTY ENOUGH TO REACH CRITICAL FIRE WEATHER
CONDITIONS...BUT WILL CONTINUE TO MONITOR.

ADDED A MENTION OF ISOLATED STORMS TO WESTERN YUMA AND FAR NORTHWEST
KIT CARSON COUNTY FOR LATE THIS AFTERNOON/EARLY THIS EVENING.
LATEST OBS SHOW A SURFACE TROUGH OVER THAT AREA.  POINT SOUNDINGS
INDICATE SOME CAPE TO WORK WITH DURING THE LATE AFTERNOON WHICH MAY
BE ENOUGH FOR AN ISOLATED STORM TO DEVELOP.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 593DM RIDGE CENTERED
OVER THE CENTRAL CONUS...WITH THE MEAN STORM THRACE WELL NORTH AND
WEST OF THE TRI-STATE REGION.

H5 RIDGE WILL STRENGTHEN TO 595-596DM BY SUN/MON AND REMAIN OVER
KS...KEEPING LARGE SCALE SUBSIDENCE IN PLACE...AND GENERALLY STABLE
CONDITIONS ACROSS THE CWA. STRENGTHENING LEE TROUGH WILL KEEP
BREEZY-WINDY CONDITIONS IN PLACE THROUGH EARLY NEXT WEEK AND STRONG
WAA ACROSS OUR CWA. PRIMARY FORECAST CHALLENGE IS HIGH/LOW TEMPS AND
MARGINAL FIRE WEATHER CONDITIONS.

BASED ON H85 TEMPS NEARING 30-31C EACH AFTERNOON WE SHOULD SEE HIGHS
WELL ABOVE NORMAL IN THE UPPER 90S/NEAR 100F EACH DAY. ONCE THIS
PATTERN IS ESTABLISHED WE SHOULD GET A BETTER HANDLE ON MIXING/H85
BIAS WHICH SHOULD MAKE THINGS A LITTLE EASIER...HOWEVER FOR NOW I
KEPT FORECAST CLOSE TO GUIDANCE. REGARDING LOW TEMPS...WITH
OVERNIGHT WINDS LIKELY REMAINING BREEZING (ESPECIALLY EAST) WE
SHOULDNT SEE AS MUCH COOLING AS MOS GUIDANCE WOULD INDICATE...SO I
TRENDED FORECAST TOWARDS ECMWF 2M GUIDANCE WHICH SEEMS TO BETTER
REFLECT THIS WARMER TREND.

REGARDING FIRE WEATHER...USING A CONSERVATIVE MIXING HEIGHT I HAVE
RH VALUES IN THE UPPER TEENS IN THE WEST THROUGH EARLY NEXT WEEK.
WITH LOWE TD/RH VALUES ALONG AND BEHIND TROUGH AXIS AND STRONGER
WINDS TO THE EAST...I AM NOT CURRENTLY ANTICIPATING MEETING THE 3HR
REQUIREMENT FOR RFW.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 1255 PM MDT SAT AUG 24 2013

SUNDAY NIGHT-TUESDAY...UPPER HIGH CENTERED OVER EASTERN
KANSAS/WESTERN MISSOURI WITH A TROUGH ACROSS THE PACIFIC NORTHWEST
INTO CALIFORNIA AT THE BEGINNING OF THE PERIOD. THE UPPER HIGH IS
FORECAST TO RETROGRADE SLOWLY WEST INTO CENTRAL KANSAS WHICH WILL
SHUNT THE BETTER MID LEVEL MOISTURE NEEDED FOR PRECIPITATION WELL
WEST AND NORTHWEST OF THE AREA LEAVING US DRY.

850 TEMPERATURES SLOWLY WARM A FEW DEGREES EACH DAY WITH HIGHS ON
MONDAY IN THE 90S WITH AROUND 101-102 IN THE TRENTON AND MCCOOK
AREAS. ON TUESDAY VERY SIMILAR CONDITIONS ALTHOUGH MAYBE A DEGREE
HIGHER. NO HIGH TEMPERATURE RECORDS EXPECTED AT PRESENT TIME. LOWS
WILL CONTINUE ABOVE NORMAL IN THE 60S...AROUND 70 IN THE HILL CITY
AND NORTON AREAS.

SOUTHERLY BREEZES TO 30 MPH EACH DAY ALSO EXPECTED.

TUESDAY NIGHT-SATURDAY...UPPER HIGH REMAINS CENTERED OVER SOUTH
CENTRAL KANSAS WEDNESDAY SLOWLY MOVING WEST THURSDAY AND BY FRIDAY
EXPECTED TO BE AS FAR WEST AS SOUTH CENTRAL COLORADO/NORTHEAST NEW
MEXICO. FOR SATURDAY LITTLE CHANGE. LITTLE TO NO CHANCE OF PRECIP
EXPECTED AS BULK OF MOISTURE NEEDED FOR PRECIPITATION WILL BE WELL
WEST OF THE AREA.

HIGH TEMPERATURES GENERALLY IN THE 90S WITH A FEW 100S POSSIBLE EACH
DAY. LOWS MILD IN THE 60S...A FEW 70S ACROSS THE FAR NORTHEAST AND
EAST. MAY SEE RECORD HIGHS IN A FEW SPOTS TOWARD THE LATTER END OF
THE EXTENDED PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1125 AM MDT SAT AUG 24 2013

VFR CONDITIONS FORECAST FOR THE 18Z TAFS. SOUTH WINDS CONTINUE TO
BE GUSTY. THE GUSTS SHOULD DECLINE SOME THIS AFTERNOON...BUT NOT
MUCH. SOUNDINGS SHOW THE GUSTS PERSISTING A FEW HOURS AFTER 0Z.
SUNDAY THE WIND SPEEDS WILL BE LOWER DUE TO SLOWER WINDS AT 850MB.


&&

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

$$

UPDATE...JTL
SHORT TERM...DR
LONG TERM...99
AVIATION...JTL







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1129 AM MDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1051 AM MDT SAT AUG 24 2013

SOUTH WINDS HAVE INCREASED THROUGH THE MORNING. LATEST HRRR/NAM RUN
SHOWS 850 MB WINDS PEAK UNTIL NOON THEN DECLINE UNTIL LATE
AFTERNOON. AM NOT COMPLETELY CONVINCED THE RELATIVE HUMIDITIES
WILL FALL ENOUGH/WINDS BE GUSTY ENOUGH TO REACH CRITICAL FIRE WEATHER
CONDITIONS...BUT WILL CONTINUE TO MONITOR.

ADDED A MENTION OF ISOLATED STORMS TO WESTERN YUMA AND FAR NORTHWEST
KIT CARSON COUNTY FOR LATE THIS AFTERNOON/EARLY THIS EVENING.
LATEST OBS SHOW A SURFACE TROUGH OVER THAT AREA.  POINT SOUNDINGS
INDICATE SOME CAPE TO WORK WITH DURING THE LATE AFTERNOON WHICH MAY
BE ENOUGH FOR AN ISOLATED STORM TO DEVELOP.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 593DM RIDGE CENTERED
OVER THE CENTRAL CONUS...WITH THE MEAN STORM THRACE WELL NORTH AND
WEST OF THE TRI-STATE REGION.

H5 RIDGE WILL STRENGTHEN TO 595-596DM BY SUN/MON AND REMAIN OVER
KS...KEEPING LARGE SCALE SUBSIDENCE IN PLACE...AND GENERALLY STABLE
CONDITIONS ACROSS THE CWA. STRENGTHENING LEE TROUGH WILL KEEP
BREEZY-WINDY CONDITIONS IN PLACE THROUGH EARLY NEXT WEEK AND STRONG
WAA ACROSS OUR CWA. PRIMARY FORECAST CHALLENGE IS HIGH/LOW TEMPS AND
MARGINAL FIRE WEATHER CONDITIONS.

BASED ON H85 TEMPS NEARING 30-31C EACH AFTERNOON WE SHOULD SEE HIGHS
WELL ABOVE NORMAL IN THE UPPER 90S/NEAR 100F EACH DAY. ONCE THIS
PATTERN IS ESTABLISHED WE SHOULD GET A BETTER HANDLE ON MIXING/H85
BIAS WHICH SHOULD MAKE THINGS A LITTLE EASIER...HOWEVER FOR NOW I
KEPT FORECAST CLOSE TO GUIDANCE. REGARDING LOW TEMPS...WITH
OVERNIGHT WINDS LIKELY REMAINING BREEZING (ESPECIALLY EAST) WE
SHOULDNT SEE AS MUCH COOLING AS MOS GUIDANCE WOULD INDICATE...SO I
TRENDED FORECAST TOWARDS ECMWF 2M GUIDANCE WHICH SEEMS TO BETTER
REFLECT THIS WARMER TREND.

REGARDING FIRE WEATHER...USING A CONSERVATIVE MIXING HEIGHT I HAVE
RH VALUES IN THE UPPER TEENS IN THE WEST THROUGH EARLY NEXT WEEK.
WITH LOWE TD/RH VALUES ALONG AND BEHIND TROUGH AXIS AND STRONGER
WINDS TO THE EAST...I AM NOT CURRENTLY ANTICIPATING MEETING THE 3HR
REQUIREMENT FOR RFW.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

A BROAD UPPER LEVEL RIDGE WILL BE WELL ESTABLISHED BY THE EXTENDED
PERIOD BEGINNING EARLY NEXT WEEK PROVIDING ABOVE NORMAL TEMPS AND
DRY CONDITIONS. IN GENERAL MODEL CONSENSUS HAS BEEN SOLID OVER THE
PAST FEW DAYS FOR THIS PERIOD...WITH THE ONLY REAL UNCERTAINTIES
BEING /1/ MAX TEMPS AND /2/ HOW THE RIDGE WILL EVOLVE LATE IN THE
WEEK.

IT LOOKS LIKE MAX TEMPS WILL PEAK EARLY IN THE WEEK...WITH
850MB TEMPS IN THE LOW 30S C AS THEY HAVE BEEN PROGGED FOR DAYS.
FULL SUNSHINE AND MIXING WILL LEAD TO HIGHS IN THE MID TO UPPER
90S...AND LOWS IN THE MID 60S IN EASTERN COLORADO TO LOW 70S FARTHER
EAST INTO KANSAS.

ADDRESSING THE SECOND POINT...WHILE THE OVERALL
PATTERN HAS BEEN CONSISTENT SOME OF THE FINE DETAILS TOWARDS THE END
OF THE WEEK ARE LOOKING A BIT LESS CERTAIN NOW. WHILE THE ECMWF AND
GEFS WERE MOVING THE RIDGE EAST AT THE END OF THE WEEK IN PAST
RUNS...THE 00Z GUIDANCE FROM GFS/GEFS/ECMWF ARE FAVORING MORE OF A
RETROGRADING RIDGE TO GO FROM CENTERED OVER KANSAS TOWARDS WESTERN
KANSAS. THIS WOULD LEAD TO A LESS FAVORABLE ENVIRONMENT FOR A
SURFACE TROUGH IN EASTERN CO AND ACCOMPANYING DEVELOPMENT OF BREEZY
SURFACE WINDS DURING THE DAY AND A MUCH WEAKER NOCTURNAL LLJ. IF
THIS PATTERN INDEED DEVELOPS THE DRY WEATHER WOULD PROBABLY EXTEND
THROUGH THE END OF THE MONTH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1125 AM MDT SAT AUG 24 2013

VFR CONDITIONS FORECAST FOR THE 18Z TAFS. SOUTH WINDS CONTINUE TO
BE GUSTY. THE GUSTS SHOULD DECLINE SOME THIS AFTERNOON...BUT NOT
MUCH. SOUNDINGS SHOW THE GUSTS PERSISTING A FEW HOURS AFTER 0Z.
SUNDAY THE WIND SPEEDS WILL BE LOWER DUE TO SLOWER WINDS AT 850MB.

&&

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

$$

UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...JTL







AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1052 AM MDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1051 AM MDT SAT AUG 24 2013

SOUTH WINDS HAVE INCREASED THROUGH THE MORNING. LATEST HRRR/NAM RUN
SHOWS 850 MB WINDS PEAK UNTIL NOON THEN DECLINE UNTIL LATE
AFTERNOON. AM NOT COMPLETELY CONVINCED THE RELATIVE HUMIDITIES
WILL FALL ENOUGH/WINDS BE GUSTY ENOUGH TO REACH CRITICAL FIRE WEATHER
CONDITIONS...BUT WILL CONTINUE TO MONITOR.

ADDED A MENTION OF ISOLATED STORMS TO WESTERN YUMA AND FAR NORTHWEST
KIT CARSON COUNTY FOR LATE THIS AFTERNOON/EARLY THIS EVENING.
LATEST OBS SHOW A SURFACE TROUGH OVER THAT AREA.  POINT SOUNDINGS
INDICATE SOME CAPE TO WORK WITH DURING THE LATE AFTERNOON WHICH MAY
BE ENOUGH FOR AN ISOLATED STORM TO DEVELOP.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 593DM RIDGE CENTERED
OVER THE CENTRAL CONUS...WITH THE MEAN STORM THRACE WELL NORTH AND
WEST OF THE TRI-STATE REGION.

H5 RIDGE WILL STRENGTHEN TO 595-596DM BY SUN/MON AND REMAIN OVER
KS...KEEPING LARGE SCALE SUBSIDENCE IN PLACE...AND GENERALLY STABLE
CONDITIONS ACROSS THE CWA. STRENGTHENING LEE TROUGH WILL KEEP
BREEZY-WINDY CONDITIONS IN PLACE THROUGH EARLY NEXT WEEK AND STRONG
WAA ACROSS OUR CWA. PRIMARY FORECAST CHALLENGE IS HIGH/LOW TEMPS AND
MARGINAL FIRE WEATHER CONDITIONS.

BASED ON H85 TEMPS NEARING 30-31C EACH AFTERNOON WE SHOULD SEE HIGHS
WELL ABOVE NORMAL IN THE UPPER 90S/NEAR 100F EACH DAY. ONCE THIS
PATTERN IS ESTABLISHED WE SHOULD GET A BETTER HANDLE ON MIXING/H85
BIAS WHICH SHOULD MAKE THINGS A LITTLE EASIER...HOWEVER FOR NOW I
KEPT FORECAST CLOSE TO GUIDANCE. REGARDING LOW TEMPS...WITH
OVERNIGHT WINDS LIKELY REMAINING BREEZING (ESPECIALLY EAST) WE
SHOULDNT SEE AS MUCH COOLING AS MOS GUIDANCE WOULD INDICATE...SO I
TRENDED FORECAST TOWARDS ECMWF 2M GUIDANCE WHICH SEEMS TO BETTER
REFLECT THIS WARMER TREND.

REGARDING FIRE WEATHER...USING A CONSERVATIVE MIXING HEIGHT I HAVE
RH VALUES IN THE UPPER TEENS IN THE WEST THROUGH EARLY NEXT WEEK.
WITH LOWE TD/RH VALUES ALONG AND BEHIND TROUGH AXIS AND STRONGER
WINDS TO THE EAST...I AM NOT CURRENTLY ANTICIPATING MEETING THE 3HR
REQUIREMENT FOR RFW.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

A BROAD UPPER LEVEL RIDGE WILL BE WELL ESTABLISHED BY THE EXTENDED
PERIOD BEGINNING EARLY NEXT WEEK PROVIDING ABOVE NORMAL TEMPS AND
DRY CONDITIONS. IN GENERAL MODEL CONSENSUS HAS BEEN SOLID OVER THE
PAST FEW DAYS FOR THIS PERIOD...WITH THE ONLY REAL UNCERTAINTIES
BEING /1/ MAX TEMPS AND /2/ HOW THE RIDGE WILL EVOLVE LATE IN THE
WEEK.

IT LOOKS LIKE MAX TEMPS WILL PEAK EARLY IN THE WEEK...WITH
850MB TEMPS IN THE LOW 30S C AS THEY HAVE BEEN PROGGED FOR DAYS.
FULL SUNSHINE AND MIXING WILL LEAD TO HIGHS IN THE MID TO UPPER
90S...AND LOWS IN THE MID 60S IN EASTERN COLORADO TO LOW 70S FARTHER
EAST INTO KANSAS.

ADDRESSING THE SECOND POINT...WHILE THE OVERALL
PATTERN HAS BEEN CONSISTENT SOME OF THE FINE DETAILS TOWARDS THE END
OF THE WEEK ARE LOOKING A BIT LESS CERTAIN NOW. WHILE THE ECMWF AND
GEFS WERE MOVING THE RIDGE EAST AT THE END OF THE WEEK IN PAST
RUNS...THE 00Z GUIDANCE FROM GFS/GEFS/ECMWF ARE FAVORING MORE OF A
RETROGRADING RIDGE TO GO FROM CENTERED OVER KANSAS TOWARDS WESTERN
KANSAS. THIS WOULD LEAD TO A LESS FAVORABLE ENVIRONMENT FOR A
SURFACE TROUGH IN EASTERN CO AND ACCOMPANYING DEVELOPMENT OF BREEZY
SURFACE WINDS DURING THE DAY AND A MUCH WEAKER NOCTURNAL LLJ. IF
THIS PATTERN INDEED DEVELOPS THE DRY WEATHER WOULD PROBABLY EXTEND
THROUGH THE END OF THE MONTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 522 AM MDT SAT AUG 24 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK. WITH LEE TROUGH IN EASTERN COLORADO STRENGTHENING
EXPECT WINDS TO INCREASE THROUGH THE TAF PERIOD...WITH SOUTHERLY
WINDS GUSTING TO 30KT AT BOTH TERMINALS THIS AFTERNOON. WHILE
GUSTY WINDS WILL DIMINISH AROUND SUNSET...SUSTAINED WINDS OVER
12KT WILL CONTINUE THROUGH TONIGHT.


&&

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

$$

UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR










AREA FORECAST DISCUSSION

NWS GOODLAND KS

 1038 AM MDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1031 AM MDT SAT AUG 24 2013

SOUTH WINDS HAVE INCREASED THROUGH THE MORNING. LATEST HRRR/NAM RUN
SHOWS 850 MB WINDS PEAK UNTIL NOON THEN DECLINE UNTIL LATE
AFTERNOON. AM NOT COMPLETELY CONVINCED THE RELATIVE HUMIDITIES
WILL FALL ENOUGH/WINDS BE GUSTY ENOUGH TO REACH CRITICAL FIRE WEATHER
CONDITIONS...BUT WILL CONTINUE TO MONITOR.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS 593DM RIDGE CENTERED
OVER THE CENTRAL CONUS...WITH THE MEAN STORM THRACE WELL NORTH AND
WEST OF THE TRI-STATE REGION.

H5 RIDGE WILL STRENGTHEN TO 595-596DM BY SUN/MON AND REMAIN OVER
KS...KEEPING LARGE SCALE SUBSIDENCE IN PLACE...AND GENERALLY STABLE
CONDITIONS ACROSS THE CWA. STRENGTHENING LEE TROUGH WILL KEEP
BREEZY-WINDY CONDITIONS IN PLACE THROUGH EARLY NEXT WEEK AND STRONG
WAA ACROSS OUR CWA. PRIMARY FORECAST CHALLENGE IS HIGH/LOW TEMPS AND
MARGINAL FIRE WEATHER CONDITIONS.

BASED ON H85 TEMPS NEARING 30-31C EACH AFTERNOON WE SHOULD SEE HIGHS
WELL ABOVE NORMAL IN THE UPPER 90S/NEAR 100F EACH DAY. ONCE THIS
PATTERN IS ESTABLISHED WE SHOULD GET A BETTER HANDLE ON MIXING/H85
BIAS WHICH SHOULD MAKE THINGS A LITTLE EASIER...HOWEVER FOR NOW I
KEPT FORECAST CLOSE TO GUIDANCE. REGARDING LOW TEMPS...WITH
OVERNIGHT WINDS LIKELY REMAINING BREEZING (ESPECIALLY EAST) WE
SHOULDNT SEE AS MUCH COOLING AS MOS GUIDANCE WOULD INDICATE...SO I
TRENDED FORECAST TOWARDS ECMWF 2M GUIDANCE WHICH SEEMS TO BETTER
REFLECT THIS WARMER TREND.

REGARDING FIRE WEATHER...USING A CONSERVATIVE MIXING HEIGHT I HAVE
RH VALUES IN THE UPPER TEENS IN THE WEST THROUGH EARLY NEXT WEEK.
WITH LOWE TD/RH VALUES ALONG AND BEHIND TROUGH AXIS AND STRONGER
WINDS TO THE EAST...I AM NOT CURRENTLY ANTICIPATING MEETING THE 3HR
REQUIREMENT FOR RFW.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 217 AM MDT SAT AUG 24 2013

A BROAD UPPER LEVEL RIDGE WILL BE WELL ESTABLISHED BY THE EXTENDED
PERIOD BEGINNING EARLY NEXT WEEK PROVIDING ABOVE NORMAL TEMPS AND
DRY CONDITIONS. IN GENERAL MODEL CONSENSUS HAS BEEN SOLID OVER THE
PAST FEW DAYS FOR THIS PERIOD...WITH THE ONLY REAL UNCERTAINTIES
BEING /1/ MAX TEMPS AND /2/ HOW THE RIDGE WILL EVOLVE LATE IN THE
WEEK.

IT LOOKS LIKE MAX TEMPS WILL PEAK EARLY IN THE WEEK...WITH
850MB TEMPS IN THE LOW 30S C AS THEY HAVE BEEN PROGGED FOR DAYS.
FULL SUNSHINE AND MIXING WILL LEAD TO HIGHS IN THE MID TO UPPER
90S...AND LOWS IN THE MID 60S IN EASTERN COLORADO TO LOW 70S FARTHER
EAST INTO KANSAS.

ADDRESSING THE SECOND POINT...WHILE THE OVERALL
PATTERN HAS BEEN CONSISTENT SOME OF THE FINE DETAILS TOWARDS THE END
OF THE WEEK ARE LOOKING A BIT LESS CERTAIN NOW. WHILE THE ECMWF AND
GEFS WERE MOVING THE RIDGE EAST AT THE END OF THE WEEK IN PAST
RUNS...THE 00Z GUIDANCE FROM GFS/GEFS/ECMWF ARE FAVORING MORE OF A
RETROGRADING RIDGE TO GO FROM CENTERED OVER KANSAS TOWARDS WESTERN
KANSAS. THIS WOULD LEAD TO A LESS FAVORABLE ENVIRONMENT FOR A
SURFACE TROUGH IN EASTERN CO AND ACCOMPANYING DEVELOPMENT OF BREEZY
SURFACE WINDS DURING THE DAY AND A MUCH WEAKER NOCTURNAL LLJ. IF
THIS PATTERN INDEED DEVELOPS THE DRY WEATHER WOULD PROBABLY EXTEND
THROUGH THE END OF THE MONTH.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 522 AM MDT SAT AUG 24 2013

VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD AT BOTH KGLD
AND KMCK. WITH LEE TROUGH IN EASTERN COLORADO STRENGTHENING
EXPECT WINDS TO INCREASE THROUGH THE TAF PERIOD...WITH SOUTHERLY
WINDS GUSTING TO 30KT AT BOTH TERMINALS THIS AFTERNOON. WHILE
GUSTY WINDS WILL DIMINISH AROUND SUNSET...SUSTAINED WINDS OVER
12KT WILL CONTINUE THROUGH TONIGHT.


&&

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

$$

UPDATE...JTL
SHORT TERM...DR
LONG TERM...JJM
AVIATION...DR







AREA FORECAST DISCUSSION

NWS PITTSBURGH PA

 613 PM EDT SAT AUG 24 2013

.SYNOPSIS...
HIGH PRESSURE AND PLEASANT WEATHER WILL CONTINUE THROUGH THE
WEEKEND. AN UPPER-LEVEL DISTURBANCE WILL APPROACH EARLY NEXT WEEK
AND WILL GIVE US THE CHANCE OF SHOWERS AND STORMS. TEMPERATURES
WILL CLIMB ABOVE NORMAL BY THE END OF THE WORK WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
600 PM UPDATE...
DEW POINTS CONTINUE TO SLOWLY DROP. NUDGED MIN TEMPS DOWN ACROSS
NORTH WITH LOWER TD/S. BROUGHT IN A LITTLE MORE CLOUDS (CIRRUS)
TOWARD MORNING. HRRR SUGGESTING SOME BLOW OFF DEBRIS FROM SYSTEM
JUST NORTH OF GREAT LAKES. KEPT A FEW MORE CLOUDS RIDGES
APPALACHIAN PLATEAU COUNTIES. WITH EAST TO NORTHEAST FLOW COULD
CONTINUE A FEW UP-SLOPE CLOUDS.
PREVIOUS DISCUSSION FOLLOWS...
DRY ADIABATIC CONDITIONS FROM CCL TO SFC HAVE DEVELOPED A SCT CU
FIELD ACROSS THE HIGHER TERRAIN AND POINTS S OF I-70. THIS FIELD
WILL CONTINUE TO GROW THIS AFTN AS TEMPS CLIMB INTO THE M-U 70S.
DAYTIME DRIVEN CU WILL WANE WITH SUNSET...LEAVING A CLR- MCLR SKY.
CROSSOVER TEMPS OF M-U 50S WOULD NOT YIELD FOG FORMATION OVERNIGHT
EVEN IN THE DEEPER HOLLOWS OF THE NRN WV MTNS.

H5 HEIGHTS BUILD SUN AS ANTICYCLONE OVER THE MIDWEST SHIFTS A
LITTLE E. BUFR SOUNDINGS ILLUSTRATE AN INC IN MID AND HIGH CLOUDS
DURING THE AFTN HRS FROM THE NW AS MSTR SPILLS OVER TOP THE NRN
PERIPHERY OF THE RIDGE. ANOTHER FACTOR FOR INC HIGH CLOUDS IS UPR
LVL DIV DEPICTED BY NCEP MDLS THE SECOND HALF OF SUN. CU TRIGGER
TEMPS WILL BE IN THE UPR 70S AGAIN TMRW AND WE WILL SURPASS THOSE
NUMBERS BY LUNCH TIME...SO ANOTHER CU FIELD CAN BE ANTICIPATED.
TWEAKED INHERITED SKY GRIDS HOWEVER FOR A LARGE PART MID AND HIGH
CLOUDS WILL BE NON - OPAQUED SO ROLLING WITH ANOTHER MSNNY FCST.
NAM12BC GRIDS USED FOR MAXT SUN...WHILE MOSGUIDE BC USED FOR MINT

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
BENIGN WEATHER PERSISTS THROUGH MONDAY WITH MID-LVL HIGH PRESSURE
STILL IN CONTROL OF OUR WEATHER DESPITE ITS WESTWARD PROGRESSION.
BELT OF STRONGER H7-H5 WINDS MAKES STEERING FLOW NW...ALLOWING A
BAROCLINIC ZONE TO DROP THROUGH THE EMPIRE STATE INTO NRN PA BY
MON EVE. STILL THINK AMOUNT OF DRY AIR INDICATED BUT -1 STD PWATS
WILL ALLOW FOR ANOTHER PCPN FREE MONDAY...HWVR AMOUNT OF INCOMING
SOLAR RADIATION WILL BE DIMINISHED THROUGH THE DAY ESPECIALLY
ACROSS I-80 CORRIDOR. H8 TEMPS UNDER LIGHT SW WINDS IN THE BL
CLIMB TO 16C...WHICH WILL PUSH TEMPS INTO THE L-M 80S. THIS COULD
BE THE WARMEST DAY TO DATE OF THE ENTIRE MONTH IF WE HIT 85F AT
PIT...WHICH SOME STATISTICAL GUIDANCE SUGGESTS.

H5 ANTICYCLONE WILL STRENGTHEN THRU WED...LEAVING FCST AREA IN
NWLY FLOW ALOFT. SVRL SHRTWV TROFS WILL PROGRESS THRU THIS FLOW
DURG THE MON NGT-WED TIMEFRAME AS DP MSTR RETURNS TO THE RGN.

PRIMARY FACTOR INFLUENCING THE CVRG AND INTENSITY OF CNVCTN DURG
THIS TIME WILL BE MID-LVL LAPSE RATES. DYNAMICALLY...PATTERN WILL
BCM MORE FAVORABLE FOR SVR WX AS WIND FIELD STRENGTHENS. BOTH
ECMWF AND GFS DEPICT CNVCTN ASSOCIATED WITH WAVES PASSING THRU MON
EVE AND TUE AFTN-EVE. POPS WERE ADJUSTED APPROPRIATELY TO REFLECT
THIS PSBLTY.

ECMWF AND GFS DIFFER ON TIMING OF SHRTWV TROF ON WED. OWING TO
UNCERTAINTIES IN TIMING...HAVE NOT INCRD POPS CONSIDERABLY ON WED
OR MENTIONED SVR WX IN HWO. BUT THIS PSBLTY WILL NEED TO BE
MONITORED CLOSELY.

CONTD MAXIMA IN THE LOW-MID 80S XPCD THRU WED. MINIMA WILL INCR
MARKEDLY MON NGT AND TUE OWING TO LOW-LVL MSTR ADVCTN...WITH LOWS
IN THE MID-UPR 60S LKLY MANY AREAS TUE NGT.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
BY LATE IN THE LONG TERM...UPPER-LEVEL RIDGE WILL SHIFT BACK TO
THE EAST AND SURFACE HIGH WILL TAKE OVER.

&&

.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
HIGH CONFIDENCE VFR FCST. WINDS BELOW 7KTS THROUGH THE PERIOD.

.OUTLOOK.../16Z SUNDAY THROUGH WEDNESDAY/...
BRIEF IFR WEATHER IS POSSIBLE MON NGT - TUE WITH THE NEXT WEATHER
SYSTEM.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$







AREA FORECAST DISCUSSION

NWS TWIN CITIES/CHANHASSEN MN

 1256 PM CDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1230 PM CDT SAT AUG 24 2013

COUPLE OF CHANGES MADE TO THE FORECAST THIS MORNING. ONE...CLOUD
COVER IS MUCH LOWER THAN WHAT WAS EXPECTED EARLIER...WHICH HAS
ALLOWED TEMPS TO WARM A BIT MORE THAN ORIGINALLY FORECAST...
ESPECIALLY IN FAR WRN MN...WHERE PLACES LIKE MADISON AND APPLETON
ARE NOW EXPECTED TO WARM INTO THE MID 90S. AS A RESULT...STARTED
THE HEAT ADVISORY TODAY OUT IN A CHUNK OF COUNTIES OUT IN WRN MN
WHERE HEAT INDICES ARE EXPECTED TO CLIMB TO AROUND 100 THIS
AFTERNOON.

OTHER CHANGE HAS BEEN MADE WITH POPS. HAVE ALL BUT REMOVED ANY
POPS THROUGH THE REST OF TODAY AND TONIGHT. DESPITE THE PRESENCE
OF A 30-40 KT LLJ...VERY POOR MID LEVEL LAPSE RATES HAS MADE IT
VERY DIFFICULT FOR THIS LLJ TO GENERATE ANY PRECIP AND CERTAINLY
THE HRRR AND HOPWRF REFLECTIVITY FORECASTS SUPPORT A DRY FORECAST
THE REST OF THE DAY. THE ONLY OUTSIDE CHANCE THE MPX AREA WILL SEE
ADDITIONAL PRECIP WILL COME OVERNIGHT OVER CENTRAL MN DEPENDING
ON HOW FAR SOUTH ROBUST CONVECTION THAT WILL FIRE OVER NE NODAK
CAN BUILD OVERNIGHT. AT THIS POINT...ALL SIGNS POINT TO IT GOING
NORTH.

18Z AVIATION DISCUSSION ADDED BELOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 227 AM CDT SAT AUG 24 2013

TSRA FINALLY DEVELOPED ALONG THE LEADING EDGE OF THE MUCH
WARMER/HUMID AIR MASS ACROSS NE NEBRASKA/FAR SE SD SINCE 1 AM.
HOWEVER...THIS HAS NOT BEEN AS WIDESPREAD AS ANTICIPATED EARLIER
WHICH I HAVE SOME RESERVATION ON COVERAGE THIS MORNING IN
SOUTHERN/CENTRAL MN. BASED ON THE CURRENT MOVEMENT OF THE TSRA IN
SE SD...SCATTERED TSRA WILL BEGIN TO AFFECT SW MN BY 11Z.

TWO FACTORS WILL INFLUENCE THE TRAJECTORY OF THE CURRENT TSRA
ACTIVITY DURING THE MORNING. FIRST...THE VEERING OF THE LLJ
ASSOCIATED WITH DEVELOPMENT EARLIER TONIGHT...AND HOW IT WILL
TRANSLATE ACROSS SOUTHERN MN. SECOND...EASTERN MN IS NOT AS
UNSTABLE WITH THE EXCEPTION AT MID LEVELS WHICH INDICATES ELEVATED
ACTIVITY...AND NOT SFC BASED. A FEW WEAK REFLECTIVITY RETURNS
ACROSS SC MN ARE LIKELY THE LEADING EDGE OF THE MID LEVEL
INSTABILITY WHICH MAY ENHANCE CONVECTION ACROSS EASTERN MN DURING
THE MORNING HRS BEFORE THE CAP STRENGTHENS. THE BEST FORECAST THRU
NOON IS TO CONTINUE THE LOW POPS ACROSS MOST OF THE FA...WITH AN
ABRUPT DECREASE IN COVERAGE BY THE AFTN DUE TO THE INCREASING
CAP. ONLY THE FAR NE FA WILL HAVE ANY CHC OF TSRA/SHRA BY THE LATE
AFTN/EVENING HRS BASED ON 70H TEMPS. THE ONLY PROBLEM WITH THIS
MORNING FORECAST IS WHETHER THE LLJ STRENGTHENS TO THE POINT THAT
CONVECTION BECOMES MORE WIDESPREAD IN THE SW...WHICH MEANS LIKELY
POPS IN SW/SC MN.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 415 AM CDT SAT AUG 24 2013

CONTINUE TO FOCUS ON THE HEAT AND RELATED IMPACTS DURING THE LONG
TERM PORTION OF THE FORECAST. BY SUNDAY AFTERNOON...925-850MB
TEMPERATURES SOAR TO AROUND +28C AS THE THERMAL RIDGE NOSES INTO
THE AREA. THE 24.00Z NAM WANTED TO DEVELOP A LARGE AREA OF
SURFACE-BASED CONVECTION FROM CENTRAL MN INTO WEST CENTRAL WI ON
SUNDAY AFTERNOON AS DIURNAL WARMING IS MAXIMIZED...BUT THINK IT MAY BE
UNDERESTIMATING THE CAPPING. HAVE THEREFORE ONLY INCLUDED 20 POPS
FOR A GOOD PORTION OF THE AREA ON SUNDAY AFTERNOON...BUT EXPECT
SLIGHTLY BETTER CHANCES TO ARRIVE SUNDAY NIGHT INTO MONDAY AS A
35-45KT LOW LEVEL JET DEVELOPS AND ADVECTION PROCESSES ENSUE. THE
HIRES NMMEAST AND ARWEAST INDICATED SHOWERS AND THUNDERSTORMS
WILL BLOSSOM AROUND/AFTER 00Z MONDAY FROM EAST CENTRAL MN AND WEST
CENTRAL WI.

HIGH TEMPERATURES FROM SUNDAY THROUGH TUESDAY WILL MOSTLY RANGE
FROM 92 TO 97 DEGREES...WITH DEWPOINTS IN THE UPPER 60S TO LOWER
70S. THIS TRANSLATES TO HEAT INDICES FROM 95 TO 105 AND LOW TEMPS
NOT DECLINING LOWER THAN THE 70S. A WEAK FRONT IS STILL ON TRACK
TO PASS ACROSS ON TUESDAY...AND REDUCE TEMPERATURES FOR
WEDNESDAY...WHEN HIGHS WILL BE SLIGHTLY COOLER AND RANGE FROM 85
TO 90 DEGREES. A FEW SHOWERS AND THUNDERSTORMS MAY ACCOMPANY THE
FRONT ON TUESDAY AND TUESDAY EVENING...GENERALLY NORTH OF
INTERSTATE 94 WHERE THE CAP IS LESS STOUT.

TEMPERATURES BEGIN TO SNEAK BACK UP INTO THE UPPER 80S AND LOWER
90S FOR THURSDAY...WITH ABOVE NORMAL TEMPERATURES FROM 85 TO 95
DEGREES CONTINUING INTO NEXT WEEKEND AS THE MID LEVEL RIDGE HANGS
ON.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1230 PM CDT SAT AUG 24 2013

NO PRECIP IS ANTICIPATED THE REST OF THE PERIOD...WITH NOTHING
MORE THAN A FEW CU AND CIRRUS EXPECTED AS THE CAP CONTINUES TO
STRENGTHEN. WINDS HAVE COME UP AS ADVERTISED BY GUIDANCE AND GOING
TAFS HANDLED THE WINDS WELL SO MADE LITTLE CHANGES. OVERNIGHT...
GUSTS WILL FALL BACK...BUT NOT MUCH OF A DROP IN SUSTAINED WINDS
IS EXPECTED AS THE PRESSURE GRADIENT WILL REMAIN TIGHT. THESE
STRONG WINDS WILL ALSO KEEP THE BOUNDARY LAYER MIXED...
SIGNIFICANTLY REDUCING THE BR/HZ POTENTIAL SUNDAY MORNING.

KMSP...HIGH CONFIDENCE FORECAST ALL AROUND.

/OUTLOOK FOR KMSP/

MON...VFR...ISOLD TSRA POSSIBLE LATE. WIND S 5-10 KTS.
TUE...VFR. WIND SW 5-10 KT...BECOMING W/NW LATE.
WED...VFR. WIND NE 5 KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     MNZ041>045-048>053-057>059-065>067-074>078-082>085-091>093.

     HEAT ADVISORY UNTIL MIDNIGHT CDT TUESDAY NIGHT FOR MNZ047-
     054>056-064-073.

     EXCESSIVE HEAT WARNING FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY
     NIGHT FOR MNZ060>063-068>070.

WI...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     WIZ014>016-023>028.

&&

$$

UPDATE...MPG
SHORT TERM...JLT
LONG TERM...LS
AVIATION...MPG







AREA FORECAST DISCUSSION

NWS BISMARCK ND

 1238 PM CDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1230 PM CDT SAT AUG 24 2013

THIS UPDATE WILL FOCUS ON THE THUNDERSTORM AREA...WHICH IS NOW
ALONG AND NORTH OF LAKE SAKAKAWEA ASSOCIATED WITH THE WARM
FRONT/COLD FRONTAL SYSTEMS. UPPED THE POPS NORTH CENTRAL...WITH
LOWER POPS SOUTH AND WEST. TEMPERATURES AND WINDS LOOK GOOD SO
FAR.

UPDATE ISSUED AT 948 AM CDT SAT AUG 24 2013

SEVERAL AREAS OF ELEVATED THUNDERSTORMS FORMING ALONG THE WARM
FRONTAL BOUNDARY ACROSS WESTERN NORTH DAKOTA...AS WELL AS NORTHWEST
NORTH DAKOTA IN THE WARM ADVECTION REGION OF THE LOW. MODEL
FORECAST SOUNDINGS SHOW A WARM MID LEVEL SHOULD INHIBIT STRONG
CONVECTION...SURFACE BASED...THROUGH EARLY AFTERNOON. AREAS OF
THUNDERSTORMS SO FAR HAVE NOT BEEN WELL ORGANIZED...AND BELIEVE
WILL HAVE TO WAIT FOR COLD FRONT`S ARRIVAL LATER THIS AFTERNOON AND
EVENING FOR THE SEVERE POTENTIAL TO KICK IN. CURRENT THINKING IS
THE THUNDERSTORMS ACROSS THE WEST WILL TREND DOWN IN THE SHORT TERM
AS THE DIURNAL LOW LEVEL JET MIXES OUT. THEN WILL WAIT FOR LATE
AFTERNOON POTENTIAL. POOL OF MOIST AIR AND VERY WARM CONDITIONS
WILL PUSH THE HEAT INDEX INTO THE ADVISORY CATEGORY THIS AFTERNOON
SOUTH CENTRAL. CONTINUE THE HEAT ADVISORY. RAISED POPS WEST
CENTRAL AND NORTHWEST WHERE ONGOING CONVECTION IS
CURRENTLY...THEN TRENDED THE POPS BACK DOWN BY NOON.

UPDATE ISSUED AT 640 AM CDT SAT AUG 24 2013

SCATTERED THUNDERSTORMS FROM JUST WEST OF WILLISTON SOUTHEAST TO
NEAR KILLDEER CONTINUE TO TRACK NORTHEAST EARLY THIS MORNING.
UTILIZED THE 10 UTC HRRR FOR GUIDANCE TO EXTRAPOLATE CURRENT
CONVECTION INTO THE NORTH CENTRAL THROUGH THE MORNING HOURS. ALSO
ADJUSTED CLOUD COVER HIGHER IN THIS SAME AREA THROUGH THE MORNING.
OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. STILL
LOOKS TO BE HOT AND HUMID THIS AFTERNOON OVER THE SOUTH CENTRAL
WITH HIGH TEMPERATURES NEAR 100 DEGREES. NO CHANGES TO HEAT
ADVISORY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 242 AM CDT SAT AUG 24 2013

HIGHLIGHTS AND CONCERNS THIS PERIOD DEAL WITH THE DECISION TO
ISSUE A HEAT ADVISORY FOR SOUTH CENTRAL NORTH DAKOTA SATURDAY
AFTERNOON INTO EARLY EVENING...AND POTENTIAL FOR SEVERE WEATHER
LATE THIS AFTERNOON THROUGH THE EVENING HOURS.

CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE AND AN ASSOCIATED WARM
FRONT OVER SOUTHEAST MONTANA. LATEST RADAR INDICATES AN AREA OF
SHOWERS AND THUNDERSTORMS IN SOUTHEAST MONTANA ARE MOVING
INTO SOUTHWEST NORTH DAKOTA THIS MORNING. THE 00Z MODEL DATA
SHIFTS THE WARM FRONT THROUGH SOUTH CENTRAL NORTH DAKOTA THIS
AFTERNOON AS LOW PRESSURE MOVES INTO SOUTHERN NORTH DAKOTA. A
COLD FRONT WILL THEN ENTER THE WEST BY MID AFTERNOON. WITH THE
WARM SECTOR OVERHEAD AND H85 TEMPS IN THE +27C TO +29C RANGE...A
WELL MIXED LAYER PER NAM/GFS SOUNDINGS WILL ALLOW FOR HIGH
TEMPERATURES TO REACH AROUND 100 DEGREES ACROSS MOST OF SOUTH
CENTRAL NORTH DAKOTA. THE RELATIVE HUMIDITY CROSS SECTIONS AND WATER
VAPOR LOOP SUGGESTS THAT SCT MID AND HIGH CLOUDS WILL BE THE MAIN
THEME TODAY WITHIN THE WARM SECTOR...AND THUS WENT ABOVE MODEL
GUIDANCE ON HIGH TEMPERATURES. A FEW DAYS AGO H85 TEMPS WERE
+26C WHEN BISMARCK REACHED 102 DEGREES. THINKING THAT TODAY WILL
BE SIMILAR. DEWPOINTS DO BEGIN TO FALL INTO THE LOWER 60S LATER
THIS AFTERNOON FROM BISMARCK TO LINTON...BUT ARE MAINTAINED IN THE
LOWER 70S IN THE JAMES RIVER VALLEY. HEAT INDICES ARE FORECAST TO
RANGE BETWEEN 100 AND 110 DEGREES WHICH COVERS ALL OF SOUTH
CENTRAL NORTH DAKOTA.

IT APPEARS THAT THE GREATEST THREAT FOR SEVERE WEATHER THIS
AFTERNOON AND EVENING WILL RESIDE IN THE WEST AND NORTH AS A
SHORTWAVE NOW LIFTING THROUGH NORTHERN UTAH MOVES INTO THE AREA
LATER TODAY. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREAT. THE MID LEVEL CAP WILL BEGIN TO ERODE BETWEEN 21Z AND 00Z
SUNDAY ACROSS CENTRAL NORTH DAKOTA. THE HIGH RESOLUTION MODELS
CONTINUE TO OFFER DIFFERENT SOLUTIONS ON HOW THINGS WILL EVOLVE
LATER THIS AFTERNOON...SO SOME UNCERTAINTY REMAINS.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 242 AM CDT SAT AUG 24 2013

MAIN FORECAST ISSUES IN THE LONG TERM WILL BE DAYTIME HIGH
TEMPERATURES AND PERIODIC THUNDERSTORM CHANCES.

THERE IS A CONTINUED GOOD AGREEMENT AMONG BOTH THE ENSEMBLE AND
DETERMINISTIC MODELS IN THE MEAN UPPER LEVEL FLOW WHICH FEATURES A
STRONG RIDGE OVER THE CENTRAL U.S. ENSEMBLE SPREAD IS NEGLIGIBLE
THROUGH ALL BUT THE VERY END OF THE EXTENDED PERIOD AND
DETERMINISTIC LARGE SCALE DIFFERENCES ARE MINIMAL. WITH THAT
SAID...THERE ARE STILL ISSUES AMONG THE DETERMINISTIC MODELS IN
RESOLVING INDIVIDUAL IMPULSES TRANSLATING  THROUGH THE BROAD UPPER
LEVEL FLOW FROM THE WESTERN U.S. INTO THE NORTHERN PLAINS.

THEREFORE THE FORECAST WILL FEATURE HOT DAYTIME HIGHS RANGING FROM
THE MID 80S NORTH TO THE MID 90S SOUTH AND MILD OVERNIGHT LOWS
MAINLY IN THE 60S...WITH A CONTINUED ALMOST DAILY CHANCE OF
THUNDERSTORMS. THERE IS REASONABLE AGREEMENT BETWEEN THE
DETERMINISTIC MODELS THAT MORE POTENT IMPULSES WILL TRAVERSE THE
AREA ON MONDAY AFTERNOON/EVENING AND AGAIN ON WEDNESDAY
AFTERNOON/EVENING. A MODEL BLEND WITH PERSISTENCE PRODUCES HIGHEST
POPS DURING THESE PERIODS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1230 PM CDT SAT AUG 24 2013

AT NOON CDT...A WARM FRONT EXTENDED INTO CENTRAL NORTH DAKOTA
WHILE A COLD FRONT WAS FOLLOWING INTO NORTHWEST NORTH DAKOTA. THE
FRONTAL SYSTEMS WILL BE THE FOCUS FOR SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EARLY EVENING. MAIN IMPACT WILL BE FELT A
KMOT...WITH A SMALLER CHANCE AT KDIK-KBIS-KISN. AFTER 06Z
MAJORITY OF THUNDERSTORMS THREAT LIKELY EAST OF THE REGION. VFR
EXPECTED.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT /7 PM MDT/ THIS EVENING FOR
NDZ019>023-025-034>037-042-045>048-050-051.

&&

$$

UPDATE...WAA
SHORT TERM...KS
LONG TERM...TWH
AVIATION...WAA







AREA FORECAST DISCUSSION

NWS HOUSTON/GALVESTON TX

 300 PM CDT SAT AUG 24 2013

.DISCUSSION...
SEEING SOME SHOWER AND THUNDERSTORM DEVELOPMENT SO FAR THIS
AFTERNOON ACROSS MAINLY THE WESTERN PORTIONS OF THE FORECAST
AREA. A WEAK SEA BREEZE BOUNDARY IS WORKING ITS WAY INLAND...
AND THINK WE COULD SEE SOME ISOLATED STORMS DEVELOP ALONG THE
BOUNDARY WITH THE PEAK OF AFTERNOON HEATING. IN RESPONSE TO
RISING PRECIPITABLE WATER VALUES AND GREATER LIFT WITH THE
APPROACH OF THE NORTH CENTRAL GULF OF MEXICO DISTURBANCE...
THE AREA IS SILL ON TRACK FOR INCREASING RAIN CHANCES BEGINNING
LATER TONIGHT NEAR THE COAST AND ACROSS OFFSHORE WATERS...THEN
A LITTLE FURTHER INLAND AS THE DAY PROGRESSES. EXPECT TO SEE LESS
COVERAGE ACROSS OUR NORTHERN COUNTIES THAT WILL BE MORE UNDER THE
INFLUENCE OF UPPER LEVEL HIGH PRESSURE. RAIN CHANCES REMAIN IN
THE FORECAST (ESPECIALLY NEAR THE COAST AND OFFSHORE) SUNDAY
NIGHT THROUGH MONDAY AS THE GULF SYSTEM SLOWLY WORKS ITS WAY
WESTWARD ACROSS THE AREA. SOME LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE BEFORE THIS EVENT COMES TO AN END...WITH SOME SPOTS
(AGAIN...ESPECIALLY NEAR THE COAST AND OFFSHORE) PROBABLY
RECEIVING SEVERAL INCHES. WILL CARRY LOWER RAIN CHANCES ON
TUESDAY...THEN HAVE NO RAIN IN THE FORECAST WEDNESDAY THROUGH
FRIDAY AS CENTRAL U.S. CENTERED UPPER LEVEL RIDGING BUILDS BACK
INTO THE AREA.

FYI - GALVESTON`S TEMPERATURE SENSOR HAS BEEN RUNNING SOME 5 TO 10
DEGREES TOO COOL. THE EQUIPMENT WILL BE CHECKED AS SOON AS POSSIBLE.

42
&&

.MARINE...
STILL SOME SHOWERS OUT IN THE SOUTHWEST COASTAL WATERS THIS
AFTERNOON. MORE SHOWERS ARE ON THEIR WAY THOUGH FROM THE EAST AS THE
TROPICAL WAVE APPROACHES SOUTHEAST TEXAS. COVERAGE WILL START TO
PICKUP TONIGHT INTO TOMORROW AND SHOULD CONTINUE THROUGH MONDAY.
LIGHT TO MODERATE EASTERLY WINDS WILL BECOME MORE SOUTHEASTERLY
SUNDAY AFTERNOON AS WAVE AXIS MOVES OFF TO THE WEST. HIGHER WINDS
AND SEAS WILL BE POSSIBLE IN THE STRONGER STORMS. 23

&&

.PREV DISCUSSION... /ISSUED 1232 PM CDT SAT AUG 24 2013/

DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.

AVIATION...
CURRENTLY SEEING SCATTERED SHOWERS FROM KCXO TO KUTS. THIS IS
FROM SOME SPEED CONVERGENCE OCCURRING AT 850MB. HRRR IS THE ONLY
MESOSCALE MODEL THAT IS CURRENTLY SHOWING THE ONGOING
PRECIPITATION AND APPEARS TO DOING A DESCENT JOB. GFS QPF FIELD
ALSO IS HINTING AT THIS. MORNING SOUNDINGS AT KLCH SHOWS DRIER AIR
IN PLACE AROUND 600MB. THIS DRY AIR APPEARS TO BE LIMITING SHOWER
DEVELOPMENT AS UPDRAFTS ARE HAVING TROUBLE PENETRATING THE
15000-16000 FT LEVEL. THIS SHOULD KEEP THUNDER ISOLATED.

MODELS ARE FORECASTING THE 850MB SPEED CONVERGENCE TO WASH OUT
LATER TODAY AND STAY MAINLY OFF TOWARDS THE NORTH OF KIAH. THERE
IS A SLIGHT CHANCE OF SOME AFTERNOON SHOWERS SOUTH THOUGH AS
CONVECTIVE TEMPERATURES ARE AROUND 90-92 DEGREES F. GIVEN LESS
SPEED CONVERGENCE TOWARDS OUR SOUTHERN TAF SITES HAVE LEFT MENTION
OF VICINITY SHOWERS OUT. KCXO AND KLBX AGAIN APPEAR TO HAVE A
CHANCE OF MVFR CONDITIONS THIS MORNING AS SOME VERY LIGHT FOG
COULD DEVELOP.

SUNDAY THE CHANCES OF RAIN INCREASE AS MOISTURE MOVES IN FROM THE
GULF. GFS IS MORE AGGRESSIVE BRINGING THE DEEPER TROPICAL MOISTURE
IN QUICKER THAT THE NAM. WILL LOOK FOR MORE MODEL CONSISTENCY ON
THIS TO HELP WITH THE TIMING AND LOCATION OF THE POSSIBLE RAIN ON
SUNDAY. 23

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      75  94  75  94  74 /  20  40  20  40  20
HOUSTON (IAH)              77  92  75  91  75 /  30  50  40  50  20
GALVESTON (GLS)            79  87  79  87  80 /  60  60  60  60  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

DISCUSSION...42
AVIATION/MARINE...23




AREA FORECAST DISCUSSION

NWS HOUSTON/GALVESTON TX

 1232 PM CDT SAT AUG 24 2013

.DISCUSSION...
SEE AVIATION FOR 18Z TAF ISSUANCE.

&&

.AVIATION...
CURRENTLY SEEING SCATTERED SHOWERS FROM KCXO TO KUTS. THIS IS
FROM SOME SPEED CONVERGENCE OCCURRING AT 850MB. HRRR IS THE ONLY
MESOSCALE MODEL THAT IS CURRENTLY SHOWING THE ONGOING
PRECIPITATION AND APPEARS TO DOING A DESCENT JOB. GFS QPF FIELD
ALSO IS HINTING AT THIS. MORNING SOUNDINGS AT KLCH SHOWS DRIER AIR
IN PLACE AROUND 600MB. THIS DRY AIR APPEARS TO BE LIMITING SHOWER
DEVELOPMENT AS UPDRAFTS ARE HAVING TROUBLE PENETRATING THE
15000-16000 FT LEVEL. THIS SHOULD KEEP THUNDER ISOLATED.

MODELS ARE FORECASTING THE 850MB SPEED CONVERGENCE TO WASH OUT
LATER TODAY AND STAY MAINLY OFF TOWARDS THE NORTH OF KIAH. THERE
IS A SLIGHT CHANCE OF SOME AFTERNOON SHOWERS SOUTH THOUGH AS
CONVECTIVE TEMPERATURES ARE AROUND 90-92 DEGREES F. GIVEN LESS
SPEED CONVERGENCE TOWARDS OUR SOUTHERN TAF SITES HAVE LEFT MENTION
OF VICINITY SHOWERS OUT. KCXO AND KLBX AGAIN APPEAR TO HAVE A
CHANCE OF MVFR CONDITIONS THIS MORNING AS SOME VERY LIGHT FOG
COULD DEVELOP.

SUNDAY THE CHANCES OF RAIN INCREASE AS MOISTURE MOVES IN FROM THE
GULF. GFS IS MORE AGGRESSIVE BRINGING THE DEEPER TROPICAL MOISTURE
IN QUICKER THAT THE NAM. WILL LOOK FOR MORE MODEL CONSISTENCY ON
THIS TO HELP WITH THE TIMING AND LOCATION OF THE POSSIBLE RAIN ON
SUNDAY. 23

&&

.PREV DISCUSSION... /ISSUED 1023 AM CDT SAT AUG 24 2013/

DISCUSSION...
SCATTERED SHOWERS AND THUNDERSTORMS ARE CONFINED TO THE COASTAL WATERS
SO FAR THIS MORNING. WITH DAYTIME HEATING...EXPECT TO SEE SOME ISOLATED
TO WIDELY SCATTERED STORM DEVELOPMENT INLAND THIS AFTERNOON THROUGH
EARLY THIS EVENING. ALL SIGNS STILL POINT TOWARD BETTER RAIN CHANCES
BEGINNING EARLY TOMORROW MORNING NEAR THE COAST AND INLAND TOMORROW
AFTERNOON AS DEEPER TROPICAL MOISTURE EDGES INTO OUR AREA FROM THE
EAST. THIS TREND IS EXPECTED TO REPEAT AGAIN ON MONDAY. BASED ON THE
MOST RECENT MODEL DATA...STILL NOT REAL CONFIDENT ON HOW FAR INLAND
THE FUTURE ACTIVITY WILL GET. FOR NOW...SEE NO REASON FOR ANY SIGNIFICANT
CHANGES TO THE FORECAST WHICH HAS HIGHER POPS NEAR THE COAST AND OFFSHORE
FOR THE NEXT THREE DAYS.  42

PREV DISCUSSION... /ISSUED 423 AM CDT SAT AUG 24 2013/

DISCUSSION...
WEAK IMPULSE CURRENTLY MOVING ACROSS INLAND PARTS OF THE AREA IS
RESPONSIBLE FOR GENERATING SOME ISO/SCT PRECIP ACROSS NW PARTS OF
CWA. BOTH SYNOPTIC & MESOSCALE MODELS SHOW LIMITED COVERAGE OF
DAYTIME ACTIVITY ACROSS MOST OF THE AREA TODAY - PROBABLY DUE TO
SOME SUBSIDENCE IN ITS WAKE IN ADDITION TO SLIGHTLY LOWER PW`S
COMPARED TO YDAY. STILL ANTICIPATE SCT ACTIVITY NEAR THE COAST
THIS MORNING.

TROF SITUATED IN THE CNTL GULF WILL BEGIN ENTERING UPPER TX COASTAL
WATERS LATE TONIGHT & SUNDAY. EXPECT INCREASING SHRA/TSRA COVERAGE
OVERNIGHT IN THE GULF AS THIS OCCURS...THEN EVENTUALLY SPREADING
INLAND DURING THE DAY SUNDAY. PW`S CLIMB FROM AROUND 1.8" TODAY TO
2.1-2.4" SUN & MON ACROSS THE SRN HALF OF THE REGION. BEST OVERALL
COVERAGE WILL PROBABLY BE LATE SUN NIGHT THRU MON AFTN WITH HIGHER
QPFS CLOSER TO THE COAST. MODELS SUGGEST MORE PRECIP COVERAGE FURTHER
INLAND THAN I WOULD`VE SUSPECTED ESP CONSIDERING THE FCST STRENGTHENING
OF THE MID LEVEL RIDGE EXTENDING DOWN INTO THE REGION FROM THE PLAINS.
WILL HESITANTLY CONTINUE ADVERTISE CHANCE POPS ACROSS NRN AREAS FOR
NOW...BUT HAVE BEEN BURNED IN THESE SIMILAR PATTERNS IN PAST WITH
PRECIP HANGING CLOSER TO THE COAST.

RAIN CHANCES WILL BEGIN TO DIMINISH ON TUE AS THE TROF AXIS & ASSOCIATED
HIGHER MOISTURE LEVELS PUSH AWAY FROM SE TX. WED-FRI SHOULD BE MOSTLY
DRY & HOT AS MID LEVEL RIDGE REGAINS CONTROL. ECMWF STILL HINTING
AT THE POSSIBILITY OF ANOTHER WWD MOVING INVERTED TROF MOVING
ACROSS THE NRN GULF TOWARD TX NEXT WEEKEND. 47

MARINE...
PER LATEST RADAR LOOPS...QUITE A BIT OF MOISTURE/SCT SHRA OUT OVER
THE COASTAL WATERS THIS MORNING. SOME OF THE ACTIVITY IS MAKING IT
INTO THE COASTAL PARTS OF SE TX. WILL LIKELY SEE A REPEAT OF YEST-
ERDAY WITH THE SEABREEZE MOVEMENT/WIND DIRECTION FOR TODAY. MOTION
OF THE TROPICAL WAVE OVER THE NRN GULF CONTINUES TO THE WEST AS IT
SHOULD MOVE INTO THE AREA DURING THE LATTER PART OF THE DAY TOMOR-
ROW (SUN). THIS SHOULD INCREASE PCPN COVERAGE AND LIKELIHOOD OF AN
INCREASE OF WINDS/SEAS BRIEFLY IN/AROUND THESE STORMS. 41

AVIATION...
WHILE MODELS ARE INDICATING THAT THE BEST POPS WILL BE TOMORROW/SUN
WITH THE APPROACH/PASSAGE OF THE TROPICAL WAVE...WE COULD STILL SEE
SOME ISO/WIDELY SCT ACTIVITY TODAY. MOVEMENT OF THE SEABREEZE ALONG
WITH DAYTIME HEATING BEING THE MAIN FACTORS. WILL LIKELY DEBATE THE
RE-INCLUSION OF VCTS/VCSH FOR THE AFTN HOURS UNTIL THE LAST MINUTE.
OTHERWISE A MOSTLY VFR FCST SAVE FOR THE VERY BRIEF MVFR CIGS EARLY
THIS MORNING. 41

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      75  94  74  94  74 /  10  40  20  40  20
HOUSTON (IAH)              76  92  75  91  75 /  30  50  40  50  20
GALVESTON (GLS)            80  89  81  89  81 /  50  50  60  60  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

AVIATION/MARINE...23




AREA FORECAST DISCUSSION...UPDATED

NWS FORT WORTH TX

 1215 PM CDT SAT AUG 24 2013

.AVIATION...
ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE THIS
AFTERNOON...WITH THE BEST TIMING FOR AFFECTING ANY AIRPORT BEING FROM
19 TO 22 UTC PER LATEST HRRR MODEL. THUS...WILL NOT INCLUDE VCSH
OR VCTS IN THE 18 UTC TAFS...BUT WILL MONITOR RADAR TRENDS THIS
AFTERNOON AND UPDATE WHEN NECESSARY.

SKIES TO REMAIN VFR THROUGH THIS FORECAST AS EAST-SOUTHEAST LIGHT
WINDS PREVAIL.   75

&&

.UPDATE...
THE UPPER HIGH CENTER HAS MOVED FROM CENTRAL KANSAS ESE TOWARD THE
OZARKS THE PAST 24 HOURS. THE RAP/HRRR AND ARW MODELS HIGH-RES
MODELS HAVE REALLY OUTPERFORMED ALL THE OTHER MODELS REGARDING
DIURNAL CONVECTION THE PAST FEW DAYS WITH LITTLE TO NO SURFACE
FOCUS AND ONLY BENIGN FORCING ALOFT. A SLIGHTLY HIGHER MOISTURE
AXIS PER PWAT ANALYSIS WILL BE FOCUSED ACROSS THE FAR W/NW
COUNTIES THIS AFTERNOON ALONG WITH HIGHER RESULTANT SURFACE-
BASED INSTABILITY. A WEAK SURFACE LOW NEAR THESE AREAS ALONG WITH
BENIGN OLD OUTFLOW BOUNDARIES WILL LEND TO SOME SURFACE FOCUS AND
LEADS ME TO BELIEVE THAT COVERAGE WILL BE SLIGHTLY HIGHER THAN
THE REST OF THE CWA. THE HRRR/ARW MODELS CONCUR ON THIS SCENARIO.

A MINOR UPDATE WILL BE ISSUED TO SLIGHTLY RAISE POPS...ESPECIALLY
ACROSS THE FAR WEST-NORTHWEST COUNTIES THIS AFTERNOON/EARLY EVENING
WHERE POPS WERE RAISED TO 30 PERCENT FOR THIS AFTERNOON. ONLY SLIGHT
CHANCES ELSEWHERE. MOST OF THE ACTIVITY SHOULD WANE QUICKLY BY
SUNSET/AFTER. INSTABILITY WILL BE SUFFICIENT FOR A STRONG STORM OR
TWO WITH GUSTY WINDS...MORE FREQUENT LIGHTNING...AND BRIEF HEAVY
DOWNPOURS.

05/

&&

.PREV DISCUSSION... /ISSUED 322 AM CDT SAT AUG 24 2013/
A STAGNANT WEATHER PATTERN WILL PERSIST ACROSS THE REGION FOR THE
COMING WEEK AS AN AMPLIFIED RIDGE OF HIGH PRESSURE REMAINS
ANCHORED OVER THE CENTRAL PLAINS. THIS PATTERN WILL KEEP NORTH
TEXAS IN DEEP EASTERLY FLOW WHICH IN TURN WILL RESULT IN HOT AND
HUMID CONDITIONS THROUGH THE LAST WEEK OF AUGUST. EXPECT
TEMPERATURES TO REMAIN SLIGHTLY ABOVE SEASONAL NORMALS WITH HIGHS
GENERALLY IN THE UPPER 90S TO AROUND 100 AND LOWS IN THE 70S.

SOME VERY WEAK ENERGY WILL CONTINUE TO ROTATE AROUND THE SOUTHERN
PERIPHERY OF THE UPPER HIGH THROUGH EARLY NEXT WEEK. THE
COMBINATION OF WEAK LARGE SCALE LIFT WITH A MOIST AND UNSTABLE
ATMOSPHERE WILL RESULT IN ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS.
THUNDERSTORM CHANCES WILL DECREASE FROM NORTH TO SOUTH BEGINNING
EARLY NEXT WEEK AS THE UPPER HIGH BUILDS FURTHER SOUTH AND SHUNTS
THE DEEPER MOISTURE SOUTH OF THE REGION. ANY SHOWERS OR STORMS
THAT DO DEVELOP OVER THE NEXT COUPLE OF DAYS WILL BE EFFICIENT RAIN
PRODUCERS DUE TO THE DEEP MOISTURE IN PLACE. STORMS WILL ALSO
HAVE THE POTENTIAL TO PRODUCE MICROBURSTS DUE TO LARGE AFTERNOON
TEMPERATURE/DEW POINT SPREADS IN THE LOW LEVELS OF THE ATMOSPHERE.

ALTHOUGH A FEW AREAS MAY SEE BENEFICIAL RAINFALL OVER THE NEXT
COUPLE OF DAYS...MOST AREAS WILL NOT SEE ANY MEASURABLE RAINFALL
THROUGH THE COMING WEEK. UNFORTUNATELY...THERE ARE NO STRONG
INDICATIONS THAT THE UPPER RIDGE WILL BREAK DOWN OR MOVE AS WE
HEAD INTO EARLY SEPTEMBER. THE ONLY GLIMMER OF HOPE FOR INCREASING
RAIN CHANCES CAN BE SEEN IN THE 00Z ECMWF SOLUTION WHICH DOES
SHIFT THE UPPER RIDGE AXIS EAST OF THE MISSISSIPPI BY LABOR DAY.

79



&&


.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 100  78  99  78  98 /  20  10  10  10  10
WACO, TX              99  74  98  74  98 /  20  10  20  10  20
PARIS, TX             96  73  98  73  96 /  20  10  10  10  10
DENTON, TX            99  74  98  76  98 /  20  10  10  10  10
MCKINNEY, TX          99  73  97  74  96 /  20  10  10  10  10
DALLAS, TX           100  79  98  78  98 /  20  10  10  10  10
TERRELL, TX           99  75  98  75  97 /  20  10  10  10  10
CORSICANA, TX         99  75  98  74  97 /  20  10  20  10  20
TEMPLE, TX            98  72  98  73  97 /  20  10  30  20  20
MINERAL WELLS, TX     99  72  98  72  96 /  30  20  10  10  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

75/






AREA FORECAST DISCUSSION

NWS LA CROSSE WI

 1244 PM CDT SAT AUG 24 2013

.UPDATE...
ISSUED AT 1244 PM CDT SAT AUG 24 2013

GOING THROUGH THIS AFTERNOON...WILL BE WATCHING THE EFFECTS OF
CONTINUED ISENTROPIC LIFT AND FRINGES OF 850-700MB MOISTURE TRANSPORT
AHEAD OF AN APPROACHING WARM FRONT FROM THE PLAINS. RAP/NAM
INDICATING MODERATE AMOUNT OF LIFT THROUGH THE AFTERNOON TO
WARRANT AT LEAST A SLIGHT CHANCE MENTION OF SHOWERS AND ISOLATED
THUNDERSTORMS AS 1-3KM MLCAPE HOVERS IN THE 500-1000J/KG RANGE.
TEMPERATURES LOOK ON TRACK WITH HIGHS TOPPING OFF IN THE 80-85
DEGREE RANGE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SAT AUG 24 2013

MAIN SHORT TERM FORECAST CONCERN IS ON PRECIPITATION CHANCES.

CURRENTLY AS OF 08Z...
WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED TROUGHING JUST
OFF THE PACIFIC NORTHWEST COAST AND OVER NEW ENGLAND...WHILE STRONG
SUBTROPICAL RIDGING DOMINATED THE CENTRAL AND SOUTHERN PLAINS.
NUMEROUS MONSOONAL SHORTWAVES WERE PRESENT ON THE WEST SIDE OF THE
RIDGE...FROM ARIZONA INTO WYOMING AND SOUTH DAKOTA. SOUTHERLY 850MB
WINDS OF 30-45 KT FROM KANSAS INTO WESTERN MN AHEAD OF THESE
SHORTWAVES ARE TRANSPORTING WARMER AND MORE MOIST AIR INTO THE UPPER
MIDWEST. PRECIPITABLE WATER VALUES HAVE CLIMBED TO 1.5-1.8 INCHES
FROM THE WESTERN PORTION OF THE FORECAST AREA INTO EASTERN PORTIONS
OF SOUTH DAKOTA AND NEBRASKA...PER SATELLITE DERIVED ESTIMATES.
MEANWHILE...850MB TEMPS HAVE CLIMBED TO 16-18C ACROSS THE FORECAST
AREA AND 22-28C ACROSS THE CENTRAL AND NORTHERN PLAINS PER RAP
ANALYSIS. THE GENERAL WARM ADVECTION PATTERN COMBINED WITH DPVA FROM
THE MONSOONAL SHORTWAVES HAS LED TO SOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS WYOMING...NEBRASKA AND SOUTH DAKOTA.

SYNOPTIC OVERVIEW...
THE SUBTROPICAL RIDGE OVER THE CENTRAL PLAINS IS PROGGED OVER THE
NEXT 24 HOURS TO BUILD INTO MISSOURI AND STRENGTHEN...CAUSING 500MB
HEIGHTS TO RISE ABOUT 30 METERS OVER THE FORECAST AREA. FOR THE MOST
PART IT APPEARS THE MONSOONAL SHORTWAVES COMING FROM THE ROCKIES
LOOK TO TRACK ACROSS THE DAKOTAS INTO NORTHWEST ONTARIO. THE ONE
SHORTWAVE OVER SOUTH DAKOTA MODELS SHOWED YESTERDAY TO COME ACROSS
THE FORECAST AREA TODAY IS PRETTY MUCH NON-EXISTENT IN MODELS TODAY.
NEVERTHELESS...WITH THE BUILDING RIDGING...THE WARM ADVECTION
PATTERN ACROSS THE UPPER MIDWEST WILL CONTINUE.

DETAILS...
THE QUESTION TODAY IS THE CHANCES OF PRECIPITATION NOW THAT THE
SHORTWAVE FROM SOUTH DAKOTA IS NO LONGER PRESENT. THE SIGNAL FOR
POSSIBLE SHOWER/THUNDERSTORM INITIATION ON THE EASTERN EDGE OF THE
850MB MOISTURE TRANSPORT IS STILL THERE...SUGGESTED BETWEEN 09-15Z
IN THE 24.00Z NAM/REGIONAL CANADIAN AND GFS. AFTER THAT...MODELS
HAVE DEFINITELY TRENDED DRIER FOR THE REST OF THE DAY. THIS MAKES
SENSE WITH THE BUILDING HEIGHTS. NOW THE 24.00Z NAM DOES TRY TO
GENERATE SOME ISOLATED CONVECTION OVER THE NORTHWEST HALF OF THE
AREA LATE IN THE AFTERNOON. HOWEVER...LOOKING AT SOUNDINGS THIS
SEEMS TO BE COMPLETELY TIED TO THE CONVECTIVE SCHEME AND ODD...WITH
MLCIN DROPPING FROM 70-80 J/KG TO 0 J/KG IN 1 HOUR WHILE A SUBSIDENT
PROFILE IS PRESENT. GIVEN THE CONSENSUS FOR A DRY AFTERNOON...WENT
IN THIS DIRECTION. BULK OF THE CONVECTION ALSO LOOKS TO STAY NORTH
OF THE FORECAST AREA TONIGHT WITH THE 850MB MOISTURE TRANSPORT
STREAM MOVING OVERHEAD...WHILE ITS NOSE IS FOCUSED FROM NORTHERN MN
ACROSS LAKE SUPERIOR AND UPPER MI. HAVE SHIFTED CHANCES NORTH TO
ONLY INCLUDE TAYLOR/CLARK NOW...TO ACCOUNT FOR THE DRYING
TREND...AND THESE MIGHT BE ABLE TO BE SHIFTED COMPLETELY OUT OF THE
AREA.

PARTIAL SUNSHINE TODAY COMBINED WITH 925/850MB TEMPS ABOUT 2C WARMER
SHOULD ALLOW HIGHS TO TOP OUT SIMILAR TO OR JUST SLIGHTLY WARMER
COMPARED TO YESTERDAY. CONDITIONS WILL BE A BIT MORE
MUGGY...THOUGH...AS HIGHER DEWPOINTS IN THE UPPER 60S TO LOW 70S
ADVECT IN ON INCREASING SOUTHERLY WINDS. THE SOUTHERLY BREEZE IS
EXPECTED TO PERSIST INTO TONIGHT...ALLOWING THE AFOREMENTIONED
DEWPOINTS TO SPREAD ACROSS THE FORECAST AREA. THE HIGHER DEWPOINTS
AND BREEZE SHOULD HELP KEEP TEMPERATURES UP IN THE MID 60S TO LOW
70S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 320 AM CDT SAT AUG 24 2013

HAZARDS...
1. HEAT. CONFIDENCE REMAINS HIGH THAT HEAT INDICES WILL EXCEED
ADVISORY CRITERIA BOTH MONDAY AND TUESDAY. A FEW LOCALIZED SPOTS
COULD EVEN TOUCH EXCESSIVE HEAT WARNING CRITERIA OF 105.
ADDITIONALLY...SUNDAY NOW LOOKS A LITTLE HIGHER FOR HEAT INDICES...
MORE CLOSER TO 100. GIVEN THESE CONDITIONS AS WELL AS WARM OVERNIGHT
LOWS...HAVE ISSUED A HEAT ADVISORY FOR SUNDAY THROUGH TUESDAY.

2. STORMS. THERE ARE PERIODIC STORM CHANCES THROUGHOUT THE LONG TERM
PORTION OF THE FORECAST...PARTICULARLY NORTH/EAST OF I-94.
HOWEVER...0-6KM AND 0-3 KM SHEAR VALUES ARE NEVER THAT IMPRESSIVE...
GENERALLY 25 KT OR LESS. THIS WILL KEEP HEAVY RAIN AS THE MOST
LIKELY HAZARD FROM THE STORMS.

SYNOPTIC OVERVIEW...
THE STRONG SUBTROPICAL RIDGE OVER MISSOURI TO START AT 12Z SUNDAY IS
WELL AGREED UPON BY 24.00Z GUIDANCE TO RETROGRADE WESTWARD THROUGH
THE MIDDLE OF THE WEEK. THIS RETROGRESSION IS CAUSED BY A SERIES OF
SHORTWAVE TROUGHS DROPPING DOWN THE EAST SIDE OF THE RIDGE INTO NEW
ENGLAND...THE MOST IMPRESSIVE OF WHICH CROSSES NEAR THE GREAT LAKES
REGION TUESDAY NIGHT. THE RETROGRESSION DOESNT LAST LONG...
THOUGH...AS A MORE POTENT UPPER TROUGH COMES INTO THE PACIFIC
NORTHWEST LATE IN THE WEEK...HELPING TO PUSH THE RIDGING AND ITS
WARMTH BACK EASTWARD.

PRECIPITATION DETAILS...
SUNDAY CONTINUES TO LOOK DRY WITH ALL SHORTWAVE AND 850MB MOISTURE
TRANSPORT FORCING TRACKING ACROSS LAKE SUPERIOR OR FARTHER NORTH.
THE 24.00Z NAM...HIRES ARW/NMM INITIATES SURFACE BASED CONVECTION
OVER CENTRAL MN LATE SUNDAY AFTERNOON...ALONG A SURFACE TROUGH. THE
CONVECTION THEN DROPS SOUTH TOWARDS I-90 IN THE EVENING. THESE
APPEAR TO BE STRONGLY DRIVEN BY TEMPERATURES REACHING 100F OR SO
ALONG THE TROUGH...WHICH IS THE CONVECTIVE TEMPERATURE. WHETHER OR
NOT THIS HAPPENS IS UNKNOWN...BUT JUST IN CASE DID INCLUDE 20-40
PERCENT CHANCES ALONG/NORTH OF I-90 IN THE EVENING. THESE CHANCES
CONTINUE INTO THE OVERNIGHT HOURS FOR A SECOND SCENARIO...WHERE
CONVECTION FIRES UP IN NORTHWEST WISCONSIN IN THE EVENING AND DROPS
SOUTH FOLLOWING CORFIDI VECTORS. THIS IS PRESENTED BY THE 24.00Z
GFS/ECMWF. IT SHOULD BE NOTED...THOUGH...THE 24.00Z CANADIAN/UKMET
ARE DRY...KEEPING ALL CONVECTION TO THE NORTH OF THE AREA. ALSO
INTERESTING TO NOTE IS THAT THE NAM...GFS AND ECMWF ARE ALL DRY
MONDAY MORNING...SUGGESTING CONVECTION WEAKENS AS IT RUNS INTO THE
CAPPING OVER THE AREA.

ALL MODELS INDICATE THAT AN OUTFLOW BOUNDARY/WARM FRONT SHOULD BE
LOCATED SOUTH OF THE OVERNIGHT CONVECTION...SETTING UP NEAR I-94 FOR
MONDAY AFTERNOON. 24.00Z GFS/ECMWF BOTH FIRE SOME CONVECTION ALONG
THIS BOUNDARY WHICH WOULD APPEAR POSSIBLE GIVEN THE HOT AND HUMID
AIRMASS IMPINGING ON IT FROM THE SOUTHWEST. THEREFORE...CARRIED 20
PERCENT CHANCES ALONG/NORTH OF I-94 FOR THE AFTERNOON. THESE CHANCES
PERSIST THROUGH MONDAY NIGHT AND TUESDAY...AIDED BY INCREASING 850MB
MOISTURE TRANSPORT AHEAD OF A MORE SIGNIFICANT SHORTWAVE TRACKING
ACROSS THE DAKOTAS...INTO NW MINNESOTA AND LAKE SUPERIOR. GREATER
CHANCES FOR CONVECTION MONDAY NIGHT AND TUESDAY SHOULD STAY OFF TO
THE NORTH AND NORTHEAST CLOSER TO THAT SHORTWAVE TRACK.

A COLD FRONT IS PROGGED TO DROP THROUGH TUESDAY NIGHT. PLENTY OF
CAPPING AHEAD OF THE FRONT SHOULD RESTRICT SURFACE BASED CONVECTION
ON IT...WITH DRY CONDITIONS LIKELY IN ITS WAKE FOR WEDNESDAY INTO
THURSDAY. CHANCES OF SHOWERS AND STORMS RETURN THURSDAY NIGHT
THROUGH FRIDAY NIGHT AS THE FRONT GRADUALLY RETURNS BACK
NORTHEASTWARD AS A WARM FRONT.

TEMPERATURE DETAILS...
SUNDAY...WITH PLENTY OF SUN...BREEZY SOUTHWEST WINDS AND 925 MB
TEMPS CLIMBING TO 26-28C...HIGH TEMPS SHOULD EASILY TOP OUT IN THE
UPPER 80S TO LOW 90S. A FEW VALLEY LOCATIONS COULD EVEN HIT THE MID
90S. WITH DEWPOINTS LIKELY IN THE UPPER 60S TO LOW 70S...PEAK HEAT
INDICES OF 95 TO 100 SHOULD BE COMMON...HIGHEST OVER THE NORTHWEST
HALF OF THE FORECAST AREA.

MONDAY...INDICATIONS ARE THAT THERE SHOULD STILL BE PLENTY OF
SUN...EVEN IF THERE IS ANY DISSIPATING MORNING CONVECTION OR
AFTERNOON DEVELOPMENT. WITH 925MB TEMPS CLIMBING FURTHER TO AROUND
28C TO POSSIBLY EVEN 30C PER GFS...HIGHS IN THE LOW TO MID 90S ARE
LIKELY. COMBINED WITH DEWPOINTS STAYING ABOUT THE SAME RESULTS IN
PEAK HEAT INDICES OF 100 TO 105.

TUESDAY...WILL HAVE TO WATCH THIS DAY CLOSELY AS IT COULD BE THE
HOTTEST OF THE WEEK. AHEAD OF THE APPROACHING COLD FRONT...A
SOUTHWEST TO WEST WIND PUSH OF THE HOT PLAINS AIR ADVECTS OVER THE
AREA. 925MB TEMPS OF 29-31C PER ECMWF/GFS ARE PROGGED WHICH COULD
PUSH TEMPS TOWARDS 100F. ONLY CONCERN IS THE LOWER SUN ANGLE
COMPARED TO SAY JULY. RAISED HIGHS A COUPLE DEGREES BUT MORE
INCREASES MAY BE NEEDED. NEW FORECAST HIGHS ARE AT RECORDS. HEAT
INDICES AGAIN LOOK TO PEAK OUT AT 100-105.

A COOL DOWN BUT STILL STAYING WELL ABOVE NORMAL IS PROGGED FOR
WEDNESDAY AND THURSDAY. FRIDAY IS A BIT MORE UNCERTAIN WITH THE
24.00Z ECMWF SHOWING ANOTHER SHORTWAVE DROPPING THROUGH THE GREAT
LAKES...SLOWING DOWN THE EASTWARD MOVEMENT OF THE UPPER RIDGE.
FRIDAY PREVIOUSLY LOOKED LIKE WHEN THE HEAT WOULD RETURN. HEAT STILL
ON TARGET TO RETURN DURING LABOR DAY WEEKEND...HOWEVER.

LEANED TOWARDS THE WARM SIDE OF RAW MODEL GUIDANCE FOR LOWS SUNDAY
NIGHT AND MONDAY NIGHT. CONSENSUS OF MODEL GUIDANCE USED THEREAFTER.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1244 PM CDT SAT AUG 24 2013

CONTINUED LIFT THROUGH THE MID-LEVELS OF THE ATMOSPHERE AHEAD OF
AN APPROACHING WARM FRONT OUT OF THE PLAINS WILL CONTINUE A SLIGHT
CHANCE OF SHRA/ISOLD THUNDER ACROSS THE AREA THROUGH THIS
AFTERNOON. SINCE THIS LIFT IS OCCURRING AOA 5KFT...ANY CLOUDS
SHOULD BE VFR IN NATURE. HAVE INCLUDED VCSH IN THE KRST/KLSE TAF
IN THE 20-01Z TIME FRAME. APPEARS ANY SHRA/THUNDER CHANCES SHIFTS
NORTHEAST OF THE AREA AFTER SUNSET. ATTENTION THEN TURNS TO LLWS
OVERNIGHT WITH MODEL WIND PROFILES SHOWING 45-50KT OUT OF THE
SOUTHWEST MATERIALIZING AOA 1500 FT AGL AFTER 04Z. FOR THIS REASON...HAVE
INCLUDED LLWS FOR BOTH KRST/KLSE TAF SITES FROM 04Z THROUGH 13Z.
LOOK FOR GUSTY SOUTH-SOUTHWEST WINDS SUNDAY AS THE PRESSURE
GRADIENT INCREASES ACROSS THE REGION. OTHERWISE...EXPECTING VFR
CONDITIONS THROUGH SUNDAY MORNING.

&&

.CLIMATE...
ISSUED AT 307 PM CDT FRI AUG 23 2013

HERE ARE SOME RECORD HIGHS FOR LA CROSSE AND ROCHESTER THROUGH LABOR
DAY WEEKEND GIVEN THE UPCOMING INCREASE IN HEAT. FOR MORE CLIMATE
INFORMATION...SEE OUR WEBSITE AND THE TOP NEWS STORY ON THE HEAT.

          LA CROSSE      ROCHESTER
          ---------      ---------

SUN 8/25   97/1948        97/1948
MON 8/26   96/1991        95/1955
TUE 8/27   95/1973        93/1984
WED 8/28   97/1955        96/1955
THU 8/29   95/1966        92/2012
FRI 8/30   97/2012        96/1941
SAT 8/31   95/1953        93/1960
SUN 9/1    98/1913        94/1937
MON 9/2    98/1937        94/1929

NORMAL HIGH TEMPERATURES THROUGH THIS PERIOD ARE 78-80 AT LA CROSSE
AND 76-78 AT ROCHESTER.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     WIZ017-029-032>034-041>044-053>055-061.

MN...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     MNZ079-086>088-094>096.

IA...HEAT ADVISORY FROM NOON SUNDAY TO MIDNIGHT CDT TUESDAY NIGHT FOR
     IAZ008>011-018-019-029-030.

&&

$$

UPDATE...DAS
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
CLIMATE...DAS/AJ