Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/31/12
AREA FORECAST DISCUSSION
NWS PUEBLO CO
355 PM MDT SUN JUL 29 2012
.SHORT TERM...
(TONIGHT AND MONDAY)
WATER VAPOR LOOPS TODAY CONTINUE TO SHOW DRY AIR PUNCHING IN UNDER
THE RIDGE ACROSS NM/SRN CO. LATEST AMSU SSM/I PRECIP WATER SAT PICS
ALSO SHOWING VALUES DROPPING OFF TO THE SOUTH...BUT STILL AN AXIS OF
HIGH PRECIP WATERS EXTENDING ACROSS NW CO. A COUPLE SHORTWAVES
EVIDENT IN WV PICS ACROSS UT/NW CO. MAIN FORCING FROM THESE MAY END
UP STAYING JUST TO THE NORTH OF THE FORECAST...BUT STILL ENOUGH
MOISTURE PRESENT WITHIN MONSOON PLUME ALOFT FOR SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS. GREATEST
COVERAGE WILL BE ACROSS CHAFFEE AND LAKE COUNTIES...AND POSSIBLY
TELLER...THOUGH EACH SUCCESSIVE HRRR RUN SEEMS TO SHIFT
AXIS OF HIGHER QPF TO THE NORTH ACROSS PARK COUNTY. WITH PRECIP
WATERS STILL AVERAGING AROUND OR SLIGHTLY BETTER THAN 100 PERCENT OF
NORMAL ACROSS THE SOUTHEAST MTS/ADJACENT PLAINS...LOCALLY HEAVY RAIN
WILL STILL BE A THREAT...PARTICULARLY FOR THE WALDO CANYON BURN SCAR
WHERE SOILS ARE SUSCEPTIBLE TO FLASH FLOODING WITH EVEN MINOR
AMOUNTS OF RAINFALL...ESPECIALLY WITH THE LIGHT RAIN THAT FELL
ACROSS THE REGION YESTERDAY. THE LOOSE SOILS OF THE CHALK CLIFFS IN
CHAFFEE COUNTY WOULD BE PRONE TO FLASH FLOODING TODAY AS WELL.
CONVECTION WHICH FIRES OFF TO THE NORTH AND MOVES ACROSS THE NE
PLAINS WILL SEND AN INITIAL CONVECTIVE OUTFLOW BOUNDARY THROUGH THE
NRN I-25 CORRIDOR...WITH A WIND SHIFT FROM THE WEST TO NORTHWEST
DURING THE EVENING PRIOR TO THE MAIN FRONT DROPPING SOUTHWARD
THROUGH THE PLAINS AFTER 03Z. LATEST NAM12 ADVECTS SOME LOWER 50S
DEW POINTS BEHIND THE FRONT INTO SE CO BY MON MORNING...THEN SHIFTS
WINDS WEAKLY FROM THE EAST AND MIXES OUT LOW LEVEL MOISTURE AGAIN BY
AFTERNOON...WITH DEW POINTS FALLING OFF INTO THE LOWER TO MID 40S BY
21Z. DRY AIR ALOFT WILL STILL BE LINGERING OVER SOUTHERN
AREAS...WITH MONSOON PLUME WITH ITS WEAK EMBEDDED IMPULSES EXTENDING
ACROSS UT THROUGH NRN AND CENTRAL CO. THUS GREATEST THREAT FOR
WIDESPREAD THUNDERSTORMS/HEAVY RAIN WILL BE ACROSS NORTHERN PORTIONS
OF THE FORECAST AREA. QUITE A BIT OF DISCREPANCIES IN THE MODEL
QPFS BETWEEN THE DRIER NAM AND THE WET GFS. GFS KEEPS DEW POINTS
ACROSS THE SE PLAINS IN THE 50S THROUGH THE AFTERNOON WITH STRONGER
EASTERLY UPSLOPE FLOW...RESULTING IN GREATER QPF FOR THE SE MTS.
ECMWF SIDES WITH THE DRIER NAM12...AND SREF IS SOMEWHERE IN
BETWEEN...THOUGH ITS QPF IS GENERALLY UNDER .25 ON AN AREAL AVERAGE
BASIS. LCLS STILL LOOK A LITTLE TOO HIGH TO JUSTIFY A FLASH FLOOD
WATCH AT THIS POINT...SO PLAN TO HOLD OFF. LATER SHIFTS CAN GET A
LOOK AT THE HIGH RES MODEL RUNS TONIGHT AND DECIDE IF ONE IS
JUSTIFIED. A LOT WILL DEPEND ON HOW FAR NORTH THE DRY AIR ALOFT
PROGRESSES OVERNIGHT. HOWEVER...THERE COULD BE A HEIGHTENED CONCERN
FOR FLASH FLOODING ON THE WALDO BURN SCAR TOMORROW VS THE PAST FEW
DAYS...AS SFC DEW POINTS SHOULD REMAIN A LITTLE HIGHER.
OTHERWISE...TEMPERATURES SHOULD BE SLIGHTLY COOLER ACROSS THE PLAINS
BEHIND THE FRONT...THOUGH STILL APPROACHING 100 NEAR THE CO/KS
BORDER. MTN AREAS WILL SEE HIGHS SIMILAR TO A COUPLE DEGREES
WARMER. -KT
.LONG TERM...
(MONDAY NIGHT THROUGH SUNDAY)
LONGER TERM METEOROLOGICAL ISSUES CONTINUE TO BE TEMPERATURES AND
POPS. 12Z/28TH GFS40 INDICATES THAT UPPER HIGH CENTERED OVER
NORTHEASTERN NEW MEXICO AT 00Z TUESDAY HOVERS OVER NEW MEXICO INTO
NEXT WEEKEND WHILE THE 12Z/28TH ECMWF SUGGESTS THAT HEALTHY UPPER
HIGH LOCATED OVER NORTHEASTERN NEW MEXICO AT 00Z TUESDAY SHIFTS
INTO NORTH TEXAS BY 06Z SATURDAY. IN ADDITION...THE 06Z/28TH DGEX
SUGGESTS THAT THE UPPER HIGH WILL BE OVER MISSOURI BY NEXT SUNDAY.
AT THE SURFACE...NORTHERLY SURGES IMPACTING PRIMARILY EASTERN
PORTIONS OF THE FORECAST DISTRICT ARE ANTICIPATED THURSDAY
MORNING...WITH A STRONGER NORTHERLY SURGE EXPECTED SATURDAY
MORNING.
THE COMBINATION OF RELATIVELY PERSISTENT DEEPER ATMOSPHERIC
MOISTURE/HIGHER PRECIPITABLE WATER VALUES IN COMBINATION WITH
THE DAILY HEATING CYCLE...THE AFORE-MENTIONED NORTHERLY SURGES
AND INCREASING UPPER ENERGY(ESPECIALLY AFTER TUESDAY) WILL ALLOW
ISOLATED TO SCATTERED PRIMARILY AFTERNOON AND EVENING
THUNDERSTORMS(SOME CONTAINING LOCALLY HEAVY RAIN AND HAIL) TO BE
NOTED OVER THE MAJORITY OF THE FORECAST DISTRICT INTO NEXT
WEEKEND.
BLEND OF LATEST COMPUTER SIMULATIONS SUGGEST THAT INCREASING
PROBABILITIES OF THUNDERSTORMS WILL BE POSSIBLE OVER PORTIONS OF
THE I-25 CORRIDOR/EASTERN COLORADO PLAINS AS THE WEEK PROGRESSES
AND INTO NEXT WEEKEND.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND FLASH
FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS THE
WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
MAXIMUM AND MINIMUM TEMPERATURES FROM TUESDAY NIGHT INTO NEXT
SUNDAY ARE STILL EXPECTED TO RUN A CATEGORY OR TWO ABOVE LATE
JULY/EARLY AUGUST CLIMATOLOGICAL AVERAGES.
&&
.AVIATION...
VCTS WILL BE POSSIBLE AT TAF SITES THROUGH 02-03Z. GUSTY ERRATIC
WINDS UP TO 35 KTS WILL BE POSSIBLE NEAR -TSRA POSSIBLY AFFECTING
THE KCOS AND KPUB SITES. VFR CIGS/VIS IN LIGHT RAIN WILL ALSO BE
POSSIBLE SHOULD STORMS BE LUCKY ENOUGH TO HIT THE TERMINAL. AT THIS
POINT THREAT LOOKS FAIRLY LOW...AND WILL MAINTAIN VCTS. CONVECTION
OVER THE MOUNTAINS SHOULD SHIFT WINDS FROM THE NORTH TO NORTHWEST AT
BOTH KCOS AND KPUB AROUND 00Z WITH GUSTS IN THE 15-25 KT RANGE.
FRONT WILL DROP THROUGH THE PLAINS AFTER 03Z...WHICH SHOULD KEEP
WINDS FROM THE NORTH AT AROUND 10-15 KTS FOR BOTH KCOS AND KPUB
THROUGH 09Z. MEANWHILE...THUNDERSTORM COVERAGE SHOULD DECREASE
AFTER SUNSET...THOUGH ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE
OVER AND NEAR THE MOUNTAINS THROUGH AT LEAST 06Z. ON MONDAY...WINDS
WILL SWING AROUND FROM THE EAST TO SOUTHEAST ACROSS THE PLAINS
DURING THE AFTERNOON WITH A SLIGHTLY BETTER CHANCE FOR -TSRA AT THE
KCOS TAF SITE DURING THE AFTERNOON. WINDS WILL REMAIN LIGHT AT KALS.
-KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER CO
1059 AM MDT SUN JUL 29 2012
.UPDATE...PRECIPIATBLE WATER VAPOR TRENDS FROM GPS SHOW A 24 HOUR
INCREASE OF 0.05 TO 0.10 INCH OVER EASTERN COLORADO WITH AN
INCREASE OF 0.10 TO 0.20 OVER WESTERN COLORADO WHERE DEEPEST
MONSOONAL MOISTURE PLUME IS LOCATED. IN ADDITION...THERE SHOULD BE
SOME WEAK Q-G VERTICAL MOTION MOVING ACROSS THE FORECAST AREA THIS
AFTERNOON AND EVENING AS RIGHT ENTRANCE REGION OF UPPER JET MOVES
ACROSS WYOMING/NORTHERN UTAH. LATEST HRRR AND RAP SHOW CONVECTION
QUICKLY DEVELOPING IN THE MOUNTAINS AND FOOTHILLS BY NOON AND THEN
SPREADING ONTO THE PLAINS AFTER 2 PM WITH DECENT COVERAGE...SO
HAVE INCREASED POPS A BIT MORE FOR THE AFTERNOON HOURS IN/NEAR THE
FRONT RANGE. THREAT OF LOCALLY HEAVY RAIN IS STILL THERE WITH
HIGHER PW VALUES...ENOUGH TO KEEP SOME FLOODING POTENTIAL IN THE
BURN SCARS ESPECIALLY IF CELLS BEGIN TO TRAIN. OTHERWISE STORM
MOTION SHOULD BE FAST ENOUGH AROUND 15 MPH TO MINIMIZE RISK OF
FLOODING IN OTHER LOCATIONS. RAIN RATES OF AT LEAST 1 INCH IN 30
MINUTES POSSIBLE.
&&
.AVIATION...CURRENT AVIATION FORECAST ON TRACK WITH HIGHER STORM
COVERAGE EXPECTED TODAY WHICH WARRANTS A TEMPO TS GROUP IN THE
TAFS THIS AFTERNOON. HIGHEST PROBABILITY FOR THUNDER WILL BE 21Z-
01Z FOR THE FRONT RANGE AIRPORTS. STORM COVERAGE HIGH ENOUGH TO
POSSIBLY SHUT OFF APPROACH GATES...WESTERN GATES 18Z-02Z AND
EASTERN GATES 22Z-03Z.
&&
.PREV DISCUSSION... /ISSUED 351 AM MDT SUN JUL 29 2012/
SHORT TERM...THERE HAS BEEN SOME SLIGHT WESTWARD PROGRESSION OF THE
UPPER HIGH WHICH HAS RESULTED IN A WESTWARD SHIFT OF THE MOISTURE
PLUME AS WELL. RESULT LOOKS TO BE AN A WEAK EASTERLY WAVE PUSHING
INTO EASTERN ARIZONA WHICH WILL SHIFT INTO NORTHERN COLORADO THIS
AFTERNOON AND EVENING. ALREADY THERE IS QUITE A BIT OF SHOWER
ACTIVITY OVER WESTERN PORTIONS OF COLORADO AHEAD OF THIS FEATURE.
INTEGRATED PW VALUES FROM GPS SHOW A SLIGHT INCREASE IN PW OVER THE
FRONT RANGE OVER THE PAST 24 HOURS WITH EVEN A GREATER INCREASE AT
GJT...AROUND 1.38" AS OF 09Z. PROFILER DATA CONTINUES TO SHOW A
SOUTHWEST FLOW ALOFT OF 20-30KT. OVERALL...LOOKS TO BE AN UPSWING IN
STORMS TODAY ESPECIALLY OVER THE NORTHEAST PLAINS GIVEN THE HIGHER
MOISTURE LEVELS AND MORE INSTABILITY THEN WE SAW YESTERDAY. CURRENT
FORECASTS LOOK IN GOOD SHAPE SHOWING LIKELY POPS IN THE MOUNTAINS
AND CHANCE POPS OVER THE PLAINS. MODEL GUIDANCE CONCURS AND SHOWING
GENERALLY 30-40 POPS OVER MANY LOCATIONS. PW VALUES EXPECTED TO
CLIMB WELL OVER AN INCH BY THIS AFTERNOON. TEMPERATURES WILL BE
SIMILAR TO FRIDAY OR A FEW DEGREES COOLER DUE TO MORE CLOUD COVER AN
EARLIER DEVELOPMENT OF STORMS THIS AFTERNOON.
LONG TERM...MOISTURE LADEN SUBTROPICAL AIR WILL CONTINUE TO
STREAM NORTHWARD OUT OF NORTHWEST MEXICO AND THE U.S. DESERT
SOUTHWEST AROUND THE OUTER EDGE OF A STRONG SUBTROPICAL HIGH
PRESSURE RIDGE MEANDERING OVER TEXAS...OKLAHOMA AND NEW MEXICO
THROUGH THE MIDDLE OF THE WEEK. 850-500MB MEAN SPECIFIC HUMIDITY
VALUES OVER THE FORECAST AREA PEAK LATE ON MONDAY AROUND 8.5
G/KG...WHICH COINCIDES WITH MEAN LAYER PRECIPITABLE WATER VALUES
AROUND 0.8 INCH OVER THE FRONT RANGE AND NEAR 1.5 INCHES IN FAR
NORTHEASTERN COLORADO. HOWEVER THESE VALUES ARE DOWN FROM READINGS
PROGGED THE DAY BEFORE AS THIS PLUME OF MONSOONAL MOISTURE SHOWS
SIGNS OF CUTTING OFF FROM ITS SOURCE REGION IN NWRN MEXICO WITH
THE UPPER RIDGE NOSING WESTWARD ACROSS NEW MEXICO. STEEP 700-500MB
LAPSE RATES AND POCKETS OF SFC BASED CAPE IN THE 500-1000 J/KG
RANGE MONDAY AFTERNOON OVER AND ALONG THE FRONT RANGE SHOULD
ALLOW SCATTERED T-STORMS TO DEVELOP IN THESE AREAS. FARTHER OUT
ACROSS THE PLAINS...MODELS DIFFER ON THE AMOUNT OF CAPE/
INSTABILITY OUT THAT WAY. THE NAM BARELY INDICATES 500 J/KG OF
CAPE BY 00Z/TUE...WHILE THE GFS INDICATES A WIDE NORTH-SOUTH BAND
OF 1600-2200 J/KG OF CAPE...NO DOUBT IN RESPONSE TO THE MODEL/S
HIGHER PW AND DEWPT VALUES OUT THERE. THE EUROPEAN MODEL FITS
NICELY BETWEEN THE TWO MODELS. WILL GO WITH A BLEND OF THE MODELS
BUT LEAN A BIT MORE ON THE DRIER NAM. HIGHER POPS OVER AND NEAR
THE HIGH TERRAIN WILL TAPER DOWN ACROSS THE PLAINS EVEN WITH ALL
OF THE SFC BASED CAPE OUT THERE AS PER THE GFS. TRANSPORT WINDS
ON MONDAY BECOME MORE WESTERLY AND SLIGHTLY GREATER IN SPEED...SO
THE THREAT OF FLASH FLOODING APPEARS LOW. OF COURSE IT DOESN/T TAKE
MUCH RAIN TO CAUSE FLASH FLOOD...DEBRIS FLOWS...ROCK SLIDES AND
THE LIKE ON THE SLOPED TERRAIN RECENTLY SCORCHED BY WILDFIRE.
AFTER MONDAY...STORM CHANCES GRADUALLY DECREASE WITH AVAILABLE
PRECIPITABLE WATER ON THE DECREASE. FEWER CLOUDS SHOULD RESULT IN
SLIGHTLY WARMER TEMPERATURES EACH DAY. BY THURSDAY THE UPPER RIDGE
CENTERED OVER NEW MEXICO FLATTENS OUT RESULTING IN WESTERLY FLOW
ALOFT OVER NORTH CENTRAL AND NORTHEAST COLORADO. WEST-NORTHWEST
BNDRY LAYER FLOW AIDS IN THE DRYING ALREADY UNDERWAY EAST OF THE
MTNS. THIS DOWNSLOPE FLOW COULD PUSH AFTERNOON TEMPERATURES NEAR
THE CENTURY MARK ON THE PLAINS..MAKING THURSDAY THE WARMEST DAY OF
THE WEEK. WARMING AND DRYING ALOFT SHOULD PRETTY PREVENT ANY STORM
FORMATION EAST OF THE FRONT RANGE. WHAT STORMS THAT MANAGE TO FORM
IN THE HIGH COUNTRY WILL BE FEW AND FAR BETWEEN. BY FRIDAY INTO
SATURDAY...MEDIUM RANGE MODELS HINT AT A MODEST INFLUX OF
SUBTROPICAL MOISTURE MAINLY;Y OVER SOUTHERN SECTIONS OF THE
FORECAST AREA. AS A RESULT COULD SEE A MODEST INCREASE IN T-STORM
COVERAGE AND SLIGHTLY COOLER TEMPERATURES.
AVIATION...LITTLE CHANGE PLANNED TO 12Z TAF ISSUANCE FOR LOCAL
TERMINALS. INCREASE CHANCES OF STORMS TODAY AND ALREADY COVERED WITH
TEMPO GROUPS STARTING AROUND MID AFTERNOON THRU EARLY EVENING. WIND
FIELDS FAIRLY LIGHT TODAY UNTIL STORMS FIRE WITH EXPECTED OUTFLOW
GUSTY AND VARIABLE WINDS.
HYDROLOGY...FLASH FLOOD THREAT A BIT HIGHER TODAY WITH HIGHER
MOISTURE VALUES AS PW VALUES WILL BE WELL ABOVE AN INCH IN THE
FOOTHILLS. RAINFALL RATES AS HIGH AS ONE INCH IN 30 MINUTES
POSSIBLE WITH THE STRONGER STORMS. BURN SCARS NEED TO BE ON ALERT
WITH LOCALIZED FLOODING POSSIBLE. STORMS STILL SHOULD BE MOVING FAIRLY
DECENT AT 10-15 KT UNLESS STORM TRAINING OCCURS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....BAKER
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
138 PM EDT SUN JUL 29 2012
.PREV DISCUSSION...
UPDATE...
/ISSUED 1052 AM EDT SUN JUL 29 2012/
MSAS DEW POINT AND PRESSURE ANALYSIS INDICATES THE FRONT IS
SITUATED ACROSS CENTRAL GEORGIA...BETWEEN ATL AND THE CSG TO MCN
AREA. FORECAST THINKING IS STILL ON TRACK WITH BEST PRECIP CHANCES
ALONG AND SOUTH OF THE FRONT SO NO CHANGES TO THE AFTERNOON POPS.
FORECAST IS OVERALL IN LINE WITH THE 11Z HRRR RUN SHOWING ISOLATED
DEVELOPMENT ACROSS NORTH GEORGIA WITH HIGHER COVERAGE ACROSS THE
SOUTHERN THIRD OF THE FORECAST AREA.
ONLY TWEAKS TO THE FORECAST ARE BASED ON CURRENT TEMP...DEW POINT
AND RADAR TRENDS. CUT DOWN ON POPS ACROSS CENTRAL GEORGIA FOR THE
REST OF THE MORNING AS THE AREA OF SHOWERS THAT PERSISTED THROUGH
MUCH OF THE MORNING HAS DISSIPATED.
11
SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
LATEST SURFACE ANALYSIS SHOWS SURFACE FRONT HAS MADE ITS WAY INTO
THE ATLANTA METRO AREA WITH LOW END SCATTERED COVERAGE OF SHOWERS
AND VERY ISOLATED THUNDERSTORMS MARKING ITS LEADING EDGE. HAVE
MADE SOME MINOR INITIAL GRID MODIFICATIONS TO TAKE POPS THROUGH
12Z. OTHERWISE...AREA IS UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES
WITH INITIALIZED UPPER LEVELS SHOWING CONTINUED TROUGH DEVELOPMENT
IN THE TENNESSEE VALLEY AND INTO THE LOCAL AREA.
FOR THE REMAINDER OF TODAY...ANTICIPATE MAIN DEVELOPMENT TO BE
ALONG THE MAIN FRONT AND ENHANCED POPS EXPECTED WITH AFTERNOON
HEATING. THIS WILL GENERALLY OCCUR OVER SOUTHERN SECTIONS OF THE
FORECAST AREA AND WILL FOCUS HIGHEST GRIDDED POPS THERE. CONTINUE
TO WATCH AREA ALONG THE FRONT OF ENHANCED DOWNDRAFT CAPE WITH
CLOSE TO 1000 J/KG ACCOUNTING FOR NUMEROUS OUTFLOWS SEEN ON RADAR
DESPITE SHALLOW CORES. ANTICIPATING THIS AREA TO SHIFT SOUTH WITH
SOME THREAT OF AN ISOLATED SEVERE WIND GUST IN STRONGEST ACTIVITY
THIS AFTERNOON.
EXPECTING SOME DRY AIR TO MIX DOWN THIS AFTERNOON BUT WITH TEMPS
LIKELY SLIGHTLY ABOVE GUIDANCE AGAIN...WILL SEE SOME ISOLATED HEAT
INDICES ABOVE 105. LIKE YESTERDAY...NOT EXPECTING WIDESPREAD
ENOUGH CONDITIONS TO WARRANT ADVISORY.
FOR MONDAY...STILL A GOOD DEAL OF DRY AIR IN PLACE AT THE MID
LEVELS TO INHIBIT CONVECTION INITIALLY. HOWEVER...A LATE ARRIVING
SHORTWAVE LOOKS TO PROVIDE TO FOCUS FOR ENHANCED ACTIVITY AND WILL
GO ABOVE GUIDANCE FOR POPS WITH LOW END CHANCE.
DEESE
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
DISSIPATING STATIONARY FRONT OR SURFACE TROUGH ACROSS THE AREA TO
START THE LONG TERM WITH AN UPPER TROUGH ALONG THE EASTERN SEABOARD.
MODELS INDICATING THE POTENTIAL FOR SHORT WAVES IN THE NW FLOW ALOFT
TO AFFECT THE AREA MONDAY NIGHT AND TUESDAY ALLOWING FOR THE CHANCE
OF SHOWERS AND THUNDERSTORMS. THIS POTENTIAL FOR SHORT WAVES TO
AFFECT THE FORECAST AREA LOOKS TO CONTINUE WEDNESDAY AND THURSDAY.
ON FRIDAY THE UPPER RIDGE BEGINS TO BUILD AND LOOKS TO CONTINUE OVER
THE AREA THE REST OF THE LONG TERM. THIS SHOULD DIMINISH SOME THE
OVERALL POTENTIAL FOR SHOWERS AND THUNDERSTORMS WITH A HIGHLY
DIURNAL NATURE TO ANY CONVECTION.
HIGH TEMPERATURES SHOULD MODERATE SOME FOR THE FIRST PART OF THE
LONG TERM WITH HIGHS IN THE LOWER HALF OF THE 90S ON THE HIGH SIDE
AND THEN WARM TO THE UPPER HALF OF THE 90S TO NEAR 100 AT WEEKS END.
BDL
&&
.AVIATION...
18Z UPDATE...
FRONT REMAINS JUST SOUTH OF THE ATL TO AHN AREA AND BEST CHANCE OF
CONVECTION WILL REMAIN ALONG AND SOUTH OF THIS FRONT. THIS MEANS
THE BEST CHANCE OF TSRA WILL BE AT MCN AND CSG THIS AFTERNOON.
THERE IS A SLIGHT CHANCE AT THE REMAINDER OF THE SITES...BUT NOT
HIGH ENOUGH TO MENTION IN THE TAF. HAVE STARTED TO SEE SOME GUSTS
ACROSS ATL SITES AND THESE WILL LAST INTO AT LEAST THE FIRST HALF
OF THE AFTERNOON.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON WIND...CIGS AND VSBY. MEDIUM CONFIDENCE ON
TSRA NOT OCCURRING AT ATL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 97 70 96 72 / 20 20 30 20
ATLANTA 96 73 94 75 / 20 20 30 20
BLAIRSVILLE 89 63 89 66 / 20 20 20 40
CARTERSVILLE 93 64 95 70 / 20 20 30 40
COLUMBUS 97 74 97 75 / 40 30 30 20
GAINESVILLE 93 71 92 72 / 20 20 30 30
MACON 97 72 96 73 / 40 30 30 20
ROME 94 64 95 70 / 20 20 30 40
PEACHTREE CITY 94 67 95 70 / 20 20 30 20
VIDALIA 93 75 96 75 / 40 40 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1052 AM EDT SUN JUL 29 2012
.UPDATE...
MSAS DEW POINT AND PRESSURE ANALYSIS INDICATES THE FRONT IS
SITUATED ACROSS CENTRAL GEORGIA...BETWEEN ATL AND THE CSG TO MCN
AREA. FORECAST THINKING IS STILL ON TRACK WITH BEST PRECIP CHANCES
ALONG AND SOUTH OF THE FRONT SO NO CHANGES TO THE AFTERNOON POPS.
FORECAST IS OVERALL IN LINE WITH THE 11Z HRRR RUN SHOWING ISOLATED
DEVELOPMENT ACROSS NORTH GEORGIA WITH HIGHER COVERAGE ACROSS THE
SOUTHERN THIRD OF THE FORECAST AREA.
ONLY TWEAKS TO THE FORECAST ARE BASED ON CURRENT TEMP...DEW POINT
AND RADAR TRENDS. CUT DOWN ON POPS ACROSS CENTRAL GEORGIA FOR THE
REST OF THE MORNING AS THE AREA OF SHOWERS THAT PERSISTED THROUGH
MUCH OF THE MORNING HAS DISSIPATED.
11
&&
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH MONDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
LATEST SURFACE ANALYSIS SHOWS SURFACE FRONT HAS MADE ITS WAY INTO
THE ATLANTA METRO AREA WITH LOW END SCATTERED COVERAGE OF SHOWERS
AND VERY ISOLATED THUNDERSTORMS MARKING ITS LEADING EDGE. HAVE
MADE SOME MINOR INITIAL GRID MODIFICATIONS TO TAKE POPS THROUGH
12Z. OTHERWISE...AREA IS UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES
WITH INITIALIZED UPPER LEVELS SHOWING CONTINUED TROUGH DEVELOPMENT
IN THE TENNESSEE VALLEY AND INTO THE LOCAL AREA.
FOR THE REMAINDER OF TODAY...ANTICIPATE MAIN DEVELOPMENT TO BE
ALONG THE MAIN FRONT AND ENHANCED POPS EXPECTED WITH AFTERNOON
HEATING. THIS WILL GENERALLY OCCUR OVER SOUTHERN SECTIONS OF THE
FORECAST AREA AND WILL FOCUS HIGHEST GRIDDED POPS THERE. CONTINUE
TO WATCH AREA ALONG THE FRONT OF ENHANCED DOWNDRAFT CAPE WITH
CLOSE TO 1000 J/KG ACCOUNTING FOR NUMEROUS OUTFLOWS SEEN ON RADAR
DESPITE SHALLOW CORES. ANTICIPATING THIS AREA TO SHIFT SOUTH WITH
SOME THREAT OF AN ISOLATED SEVERE WIND GUST IN STRONGEST ACTIVITY
THIS AFTERNOON.
EXPECTING SOME DRY AIR TO MIX DOWN THIS AFTERNOON BUT WITH TEMPS
LIKELY SLIGHTLY ABOVE GUIDANCE AGAIN...WILL SEE SOME ISOLATED HEAT
INDICES ABOVE 105. LIKE YESTERDAY...NOT EXPECTING WIDESPREAD
ENOUGH CONDITIONS TO WARRANT ADVISORY.
FOR MONDAY...STILL A GOOD DEAL OF DRY AIR IN PLACE AT THE MID
LEVELS TO INHIBIT CONVECTION INITIALLY. HOWEVER...A LATE ARRIVING
SHORTWAVE LOOKS TO PROVIDE TO FOCUS FOR ENHANCED ACTIVITY AND WILL
GO ABOVE GUIDANCE FOR POPS WITH LOW END CHANCE.
DEESE
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
/ISSUED 350 AM EDT SUN JUL 29 2012/
DISSIPATING STATIONARY FRONT OR SURFACE TROUGH ACROSS THE AREA TO
START THE LONG TERM WITH AN UPPER TROUGH ALONG THE EASTERN SEABOARD.
MODELS INDICATING THE POTENTIAL FOR SHORT WAVES IN THE NW FLOW ALOFT
TO AFFECT THE AREA MONDAY NIGHT AND TUESDAY ALLOWING FOR THE CHANCE
OF SHOWERS AND THUNDERSTORMS. THIS POTENTIAL FOR SHORT WAVES TO
AFFECT THE FORECAST AREA LOOKS TO CONTINUE WEDNESDAY AND THURSDAY.
ON FRIDAY THE UPPER RIDGE BEGINS TO BUILD AND LOOKS TO CONTINUE OVER
THE AREA THE REST OF THE LONG TERM. THIS SHOULD DIMINISH SOME THE
OVERALL POTENTIAL FOR SHOWERS AND THUNDERSTORMS WITH A HIGHLY
DIURNAL NATURE TO ANY CONVECTION.
HIGH TEMPERATURES SHOULD MODERATE SOME FOR THE FIRST PART OF THE
LONG TERM WITH HIGHS IN THE LOWER HALF OF THE 90S ON THE HIGH SIDE
AND THEN WARM TO THE UPPER HALF OF THE 90S TO NEAR 100 AT WEEKS END.
BDL
AVIATION...
12Z UPDATE...
/ISSUED 741 AM EDT SUN JUL 29 2012/
FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE ATL AREA TERMINALS AND
ANTICIPATE VFR CONDITIONS FOR THE REMINDER OF THIS CYCLE. WILL KEEP
PROB30 FOR NOW FOR CSG AND MCN AS FRONT PUSHES THROUGH AT TIME OF
MAX HEATING.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON ALL ELEMENTS
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 97 70 96 72 / 20 20 30 20
ATLANTA 96 73 94 75 / 20 20 30 20
BLAIRSVILLE 89 63 89 66 / 20 20 20 40
CARTERSVILLE 93 64 95 70 / 20 20 30 40
COLUMBUS 97 74 97 75 / 40 30 30 20
GAINESVILLE 93 71 92 72 / 20 20 30 30
MACON 97 72 96 73 / 40 30 30 20
ROME 94 64 95 70 / 20 20 30 40
PEACHTREE CITY 94 67 95 70 / 20 20 30 20
VIDALIA 93 75 96 75 / 40 40 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...DEESE
LONG TERM....BDL
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1015 PM CDT MON JUL 30 2012
.DISCUSSION...
310 PM CDT
SHORT TERM...THIS EVENING THROUGH THURSDAY...
PRIMARY CONCERN IS CONVECTIVE CHANCES THIS EVENING ACROSS NORTHERN
ILLINOIS. WATER VAPOR IMAGERY TODAY SHOWS STRONG MIDLEVEL RIDGING
CENTERED OVER THE SOUTHERN PLAINS AND A FAIRLY STRONG SHORTWAVE
TROUGH OVER ONTARIO...WITH ANOTHER TROUGH OFF THE PACIFIC NORTHWEST
COAST. THE TROUGH OVER ONTARIO WILL DIG SOUTHEAST...WITH ASSOCIATED
SURFACE LOW DRAGGING COOL FRONT ACROSS LAKE MICHIGAN AND ACROSS CWA
THIS EVENING THROUGH TONIGHT.
THIS EVENING...THOUGH THE BEST FORCING IN TERMS OF POSITIVE
VORTICITY ADVECTION WILL BE FOCUSED NORTHEAST OF THE CWA CLOSER TO
THE TROUGH AXIS...IT APPEARS THERE WILL BE DECENT CONVERGENCE ALONG
AND AHEAD OF THE COOL FRONT...ALONG WITH 0-6 KM BULK SHEAR VALUES
INCREASING TO 30 TO 35 KT AND NORTHERN ILLINOIS BEING IN THE EXIT
REGION OF AN ~80 KT UPPER LEVEL JET STREAK. SO THERE IS SOME SUPPORT
FOR ORGANIZED UPDRAFTS. SUSPECT THAT THE MLCAPE BEING PROGGED THIS
BY THE NAM AND RAP ACROSS FAR NORTHERN IL...IN EXCESS OF 2500 J/KG
IS A BIT OVERDONE BECAUSE FCST SURFACE TEMPS AND DEWPOINTS ARE
LIKELY A BIT TOO HIGH...BUT THERE SHOULD STILL BE AT LEAST 1500 J/KG
TO TAP INTO...WITH MINIMAL CIN. WITH TEMPERATURES ONLY SLOWLY
COOLING AHEAD OF THE FRONT...LOW LEVEL LAPSE RATES ARE EXPECTED TO
REMAIN FAIRLY STEEP AND DRY AIR IN THE LOWER LEVELS MAY SUPPORT
DCAPE VALUES IN EXCESS OF 1000 J/KG. THUS PRIMARY THREAT WITH ANY
TSRA IS EXPECTED TO BE DAMAGING WIND GUSTS...THOUGH THE GOOD DEEP
LAYER SHEAR COULD ALSO ALLOW FOR AT LEAST MARGINALLY SEVERE HAIL.
HAVE INCREASED POPS JUST A BIT ALONG AND NORTH OF I-80...THOUGH
STILL EXPECTING SCATTERED COVERAGE AT MOST...WITH EARLY EVENING
POPS CONFINED TO CLOSER TO THE WISCONSIN BORDER...SPREADING INTO
THE CHICAGO AREA LATER IN THE EVENING. DIURNAL DECREASE IN
INSTABILITY LATER THIS EVENING AND OVERNIGHT WILL LIKELY LEND TO
DECREASE IN INTENSITY AND COVERAGE OF CONVECTION. WILL MAINTAIN
LOW POPS FOR ISOLATED SHRA/TSRA AFTER MIDNIGHT AS THE FRONT PUSHES
THROUGH. KEPT THE INHERITED SLIGHT POPS TUESDAY MORNING PORTIONS
OF NORTHWEST INDIANA MAINLY EAST OF I-65...WITH THE FRONT EXPECTED
TO ON THE DOORSTEP BY THAT TIME. THE THING TO WATCH FOR WOULD BE A
SLOWER FRONTAL TIMING...WHICH MAY ALLOW SOME INSTABILITY TO
REBUILD AND PRESENT SOME OPPORTUNITY FOR THE FAR SOUTHEAST CWA TO
SEE TSRA LATE MORNING/EARLY AFTERNOON. FOR NOW...DO NOT THINK THIS
IS A LIKELY SCENARIO AND HAVE THE WHOLE CWA DRY AFTER 15Z TUESDAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON TUESDAY...WITH
NORTHERLY WINDS...THOUGH THE AIR MASS REALLY WONT BE MUCH COOLER.
AREAS AWAY FROM THE LAKE SHOULD ACTUALLY REACH NEAR OR A BIT ABOVE
90 UNDER FULL SUN...WITH ONSHORE WINDS KEEPING THE LAKEFRONT IN THE
MID 80S. THE MOST NOTICEABLE DIFFERENCE BEHIND THE FRONT IS EXPECTED
TO BE A DRIER AIR MASS. THUS DESPITE ABOVE NORMAL TEMPERATURES...THE
NORTHERLY BREEZE AND MANAGEABLE HUMIDITY LEVELS WILL MAKE IT A
FAIRLY COMFORTABLE DAY...ESPECIALLY CONSIDERING ALL THE EXTREME HEAT
WEVE SEEN THIS SUMMER. WEDNESDAY WILL BE SIMILARLY WARM AND
SUNNY...EXCEPT WITH MUCH LIGHTER WINDS WITH HIGH PRESSURE OVERHEAD. IF
WINDS ARENT ONSHORE TO START TO THE DAY ALONG THE LAKEFRONT...A LAKE
BREEZE SHOULD BE ABLE TO GET GOING QUICKLY WITH SUCH LIGHT FLOW OVER
THE AREA. THIS WILL AGAIN LIMIT HIGH TEMPERATURES A BIT ALONG THE
LAKESHORE.
THURSDAY PRESENTS A MORE INTERESTING SCENARIO IN TERMS OF THE HIGH
TEMPERATURE FORECAST. THE CWA WILL NOT BE IN A FAVORED AREA WITH
REGARD TO THE POSITION OF THE CENTER OF THE MIDLEVEL RIDGE...WHICH
WILL STILL BE OVER THE SOUTHERN PLAINS. HOWEVER...AN 850 MB THERMAL
RIDGE WILL PUSH INTO THE AREA WITH WARM ADVECTION BRINGING 850 MB
TEMPS TO HIGHER THAN 20C BY THE AFTERNOON...SUCH AS ON THE WELL
PERFORMING ECMWF MODEL. WITH FULL SUN AND DEEP MIXING...THIS WOULD
SUPPORT HOT TEMPERATURES IN THE MID AND UPPER 90S. HOWEVER...BOTH
THE NAM AND ECMWF...WHICH HAVE THE HOTTEST MAX TEMPS FCST...ALSO
SUGGEST FAIRLY HIGH RH AT THE MID AND UPPER LEVELS...WHICH COULD BE
IN THE FORM OF CONVECTIVE MID AND HIGH CLOUD DEBRIS. THINK CLOUDS
WILL BE THE LIMITING FACTOR FOR TEMPS ON THURSDAY...BUT WITH THE
VERY WARM THERMAL PROFILES...RAISED TEMPS A FEW DEGREES FROM
INHERITED TO MAINLY LOW 90S. IF THERE IS LESS CLOUD
COVER...CERTAINLY COULD SEE THE HOTTER TEMPS REALIZED. ALSO...WINDS
ALOFT ARE EXPECTED TO BE WEAK ENOUGH TO ALLOW FOR A LATE DAY LAKE
BREEZE TO PUSH INLAND...WHICH MAY BRING SOME MINOR COOLING.
FORCING FOR CONVECTION LOOKS RATHER WEAK AND MAINLY THURSDAY
AFTERNOON...WITH SHORT WAVE MOVING TO NORTH AND WEAK COOL FRONT
STARTING TO DROP INTO AREA...BUT WILL MAINTAIN INHERITED SLIGHT POPS
FOR NOW FOR SHRA/TSRA. MOST OF THE AREA WILL LIKELY REMAIN DRY.
RC
LONG TERM...THURSDAY EVENING THROUGH MONDAY..
SHORT WAVE MOVING THROUGH THE NORTHERN GREAT LAKES THU EVENING WITH
ASSOCIATED WEAK SURFACE TROF/FRONT DROPPING INTO NORTHERN
IL/NORTHWEST IN. WITH BEST FORCING FURTHER NORTH AND ONLY WEAK
SURFACE CONVERGENCE...AND CONSIDERING STRENGTH OF ONGOING
DROUGHT...WILL ONLY CARRY 20-30 PCT POPS. REMNANTS OF FRONT THEN
HANG UP OVER THE AREA FRIDAY BUT AGAIN WITH ONLY WEAK LOW LEVEL
CONVERGENCE AND NO UPPER LEVEL SUPPORT...WILL JUST MAINTAIN SLIGHT
CHANCE POPS FOR FRIDAY. GFS PUSHES FRONT THROUGH AND DEVELOPS EAST
WINDS OVER THE AREA FRIDAY WHILE ECMWF HAS A WEAK WISHY WASHY
SURFACE PATTERN. EITHER WAY LAKE BREEZE LIKELY TO KEEP TEMPS IN LOW
TO MID 80S LAKEFORNT BUT NEAR 90 SOUTH TOWARDS PONTIAC.
MEANWHILE MUCH MORE POTENT TROF/UPPER LOW BARRELS INTO WESTERN
CANADA COAST WED AND PLOWS THROUGH NORTHERN ROCKIES AND INTO THE
NORTHERN PLAINS THU AND FRI. THIS WILL ACT TO SHOVE UPPER RIDGE AND
ASSOCIATED HEAT DOME EASTWARD INTO THE MIDWEST AND GREAT LAKES BY
SATURDAY. SOUTHWEST FLOW AHEAD OF APPROACHING TROF PUSHES 850 TEMPS
TO AROUND 22C SATURDAY. WITH UNCERTAINTY ON CLOUD COVER HESITANT TO
RAISE TEMPS TOO MUCH. WILL GO WITH TEMPS IN LOWER 90S BUT MID TO
UPPER 90S NOT OUT OF THE QUESTION IF WE GET ENOUGH SUN. BEST CHANCE
OF WIDESPREAD RAIN IN A LONG TIME SAT AFTN AND EVENING AS STRONG
UPPER TROF/UPPER LOW MOVES THROUGH THE GREAT LAKES AND STRONG COLD
FRONT PUSHES THROUGH THE AREA. 12Z ECMWF A BITY SLOWER ON ARRIVAL OF
FRONT AND THUNDERSTORMS...MORE LIKELY SAT NIGHT INTO SUN MORNING.
TURNING COOLER AND DRIER SUN AND MON.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* PSBL SHRA ARRIVING ARND 5Z THRU 09Z.
* SOUTH WINDS WILL SLOWLY BECOME SOUTHWEST...THEN BEHIND THE
FRONTAL BOUNDARY TURN NORTHWEST/NORTH.
* WINDS ARE EXPECTED TO TURN NE/E LATE TUE MORNING.
BEACHLER
//DISCUSSION...UPDATED 00Z...
VISIBLE IMAGERY EARLY THIS EVENING SHOWS THUNDERSTOMS BLOSSOMING
ALONG THE FRONTAL BOUNDARY THAT HAS PUSHED INTO NORTHEAST
WISC/UPPER PENINSULA OF MI...WITH A TRAILING FRONTAL BOUNDARY
STRETCHING SOUTHWEST THROUGH FAR NORTHEAST IA. WINDS HAVE
REMAINED SLIGHTLY SOUTHWEST...AND GUIDANCE IS INDICATING WINDS
BACK BACK TO THE SOUTHEAST BEFORE THE BOUNDARY ARRIVES LATER
TONIGHT. GUIDANCE HAS ALSO BACKED OFF ON THE TIMING/PLACEMENT OF
THE SHRA/TSRA...AND A FEW GUIDANCE MEMBERS EVEN SUGGEST VERY
MINIMAL PRECIP WILL OCCUR WITH FRONTAL PASSAGE. WHICH COMPLICATES
THE TAF FORECAST. NONETHELESS HAVE OPTED TO MAINTAIN A DRY
FORECAST...AND WILL CONTINUE TO MONITOR. ONCE THE BOUNDARY PUSHES
THROUGH THE AIRFIELDS...WINDS WILL VEER WEST/NORTHWEST. MID-LVL
CLOUDS WILL CONTINUE TO LINGER BEHIND THE FRONTAL BOUNDARY. THEN
WINDS VEER NORTHEAST LATE TUE MORNING.
WINDS MAY CONTINUE TO VEER NORTHEAST/EAST WITH A POSSIBLE LAKE
BREEZE TUE AFTN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* LOW CONFIDENCE IN POTENTIAL FOR SHRA/TSRA.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
* MEDIUM CONFIDENCE IN AIRFIELDS REMAINING DRY.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY THROUGH SATURDAY...VFR. CHC SHRA/TSRA W/PATCHY MVFR CIGS.
SUNDAY...VFR.
BEACHLER
&&
.MARINE...
226 PM CDT
LOW PRESSURE MOVING ACROSS SOUTHERN ONTARIO...WILL DRAG A COLD FRONT
DOWN THE LAKE TONIGHT. SOME STRONG TO SEVERE THUNDERSTORMS COULD
OCCUR ACROSS THE LAKE THIS EVENING AHEAD OF THE FRONT. ONCE THE
FRONT PASSES THE WINDS WILL SWITCH OUT OF THE NORTH UP TO 25 KT.
THESE STRONGER WINDS WILL CONTINUE ACROSS THE SOUTH HALF OF THE LAKE
DURING THE DAY ON TUESDAY. WAVES OVER 4 FEET ARE POSSIBLE ALONG THE
INDIANA NEAR SHORE WATERS. THIS COULD RESULT IN HAZARDS TO SMALL
CRAFT FOR TUESDAY EVENING THROUGH WEDNESDAY MORNING. HIGH PRESSURE
WILL BUILD IN ACROSS THE LAKE TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL RESULT IN ABATING WINDS FOR A PERIOD TUESDAY NIGHT INTO
WEDNESDAY.
THE WINDS LOOK TO TURN SOUTHERLY AT 10 TO 20 KT AGAIN BY THURSDAY AS
THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO VALLEY. ANOTHER
AREA OF LOW PRESSURE MAY PUSH ANOTHER COLD FRONT ACROSS THE LAKE
LATE THURSDAY AND THURSDAY NIGHT...BRINGING ANOTHER PUSH OF NORTHERLY
FLOW DOWN THE LAKE. IN THE EXTENDED PERIOD IT APPEARS THAT A
STRONGER STORM SYSTEM MAY MOVE ACROSS THE UPPER MIDWEST AND GREAT
LAKES REGION OVER THE WEEKEND. THIS COULD PRODUCE A PERIOD OF
STRONGER WINDS ACROSS THE LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ014...10 AM TUESDAY TO 10 AM
WEDNESDAY.
IN...HIGH RIP CURRENT RISK...INZ001-INZ002...10 AM TUESDAY TO 10 AM
WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...4 PM
TUESDAY TO 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
702 PM CDT MON JUL 30 2012
.DISCUSSION...
310 PM CDT
SHORT TERM...THIS EVENING THROUGH THURSDAY...
PRIMARY CONCERN IS CONVECTIVE CHANCES THIS EVENING ACROSS NORTHERN
ILLINOIS. WATER VAPOR IMAGERY TODAY SHOWS STRONG MIDLEVEL RIDGING
CENTERED OVER THE SOUTHERN PLAINS AND A FAIRLY STRONG SHORTWAVE
TROUGH OVER ONTARIO...WITH ANOTHER TROUGH OFF THE PACIFIC NORTHWEST
COAST. THE TROUGH OVER ONTARIO WILL DIG SOUTHEAST...WITH ASSOCIATED
SURFACE LOW DRAGGING COOL FRONT ACROSS LAKE MICHIGAN AND ACROSS CWA
THIS EVENING THROUGH TONIGHT.
THIS EVENING...THOUGH THE BEST FORCING IN TERMS OF POSITIVE
VORTICITY ADVECTION WILL BE FOCUSED NORTHEAST OF THE CWA CLOSER TO
THE TROUGH AXIS...IT APPEARS THERE WILL BE DECENT CONVERGENCE ALONG
AND AHEAD OF THE COOL FRONT...ALONG WITH 0-6 KM BULK SHEAR VALUES
INCREASING TO 30 TO 35 KT AND NORTHERN ILLINOIS BEING IN THE EXIT
REGION OF AN ~80 KT UPPER LEVEL JET STREAK. SO THERE IS SOME SUPPORT
FOR ORGANIZED UPDRAFTS. SUSPECT THAT THE MLCAPE BEING PROGGED THIS
BY THE NAM AND RAP ACROSS FAR NORTHERN IL...IN EXCESS OF 2500 J/KG
IS A BIT OVERDONE BECAUSE FCST SURFACE TEMPS AND DEWPOINTS ARE
LIKELY A BIT TOO HIGH...BUT THERE SHOULD STILL BE AT LEAST 1500 J/KG
TO TAP INTO...WITH MINIMAL CIN. WITH TEMPERATURES ONLY SLOWLY
COOLING AHEAD OF THE FRONT...LOW LEVEL LAPSE RATES ARE EXPECTED TO
REMAIN FAIRLY STEEP AND DRY AIR IN THE LOWER LEVELS MAY SUPPORT
DCAPE VALUES IN EXCESS OF 1000 J/KG. THUS PRIMARY THREAT WITH ANY
TSRA IS EXPECTED TO BE DAMAGING WIND GUSTS...THOUGH THE GOOD DEEP
LAYER SHEAR COULD ALSO ALLOW FOR AT LEAST MARGINALLY SEVERE HAIL.
HAVE INCREASED POPS JUST A BIT ALONG AND NORTH OF I-80...THOUGH
STILL EXPECTING SCATTERED COVERAGE AT MOST...WITH EARLY EVENING
POPS CONFINED TO CLOSER TO THE WISCONSIN BORDER...SPREADING INTO
THE CHICAGO AREA LATER IN THE EVENING. DIURNAL DECREASE IN
INSTABILITY LATER THIS EVENING AND OVERNIGHT WILL LIKELY LEND TO
DECREASE IN INTENSITY AND COVERAGE OF CONVECTION. WILL MAINTAIN
LOW POPS FOR ISOLATED SHRA/TSRA AFTER MIDNIGHT AS THE FRONT PUSHES
THROUGH. KEPT THE INHERITED SLIGHT POPS TUESDAY MORNING PORTIONS
OF NORTHWEST INDIANA MAINLY EAST OF I-65...WITH THE FRONT EXPECTED
TO ON THE DOORSTEP BY THAT TIME. THE THING TO WATCH FOR WOULD BE A
SLOWER FRONTAL TIMING...WHICH MAY ALLOW SOME INSTABILITY TO
REBUILD AND PRESENT SOME OPPORTUNITY FOR THE FAR SOUTHEAST CWA TO
SEE TSRA LATE MORNING/EARLY AFTERNOON. FOR NOW...DO NOT THINK THIS
IS A LIKELY SCENARIO AND HAVE THE WHOLE CWA DRY AFTER 15Z TUESDAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON TUESDAY...WITH
NORTHERLY WINDS...THOUGH THE AIR MASS REALLY WONT BE MUCH COOLER.
AREAS AWAY FROM THE LAKE SHOULD ACTUALLY REACH NEAR OR A BIT ABOVE
90 UNDER FULL SUN...WITH ONSHORE WINDS KEEPING THE LAKEFRONT IN THE
MID 80S. THE MOST NOTICEABLE DIFFERENCE BEHIND THE FRONT IS EXPECTED
TO BE A DRIER AIR MASS. THUS DESPITE ABOVE NORMAL TEMPERATURES...THE
NORTHERLY BREEZE AND MANAGEABLE HUMIDITY LEVELS WILL MAKE IT A
FAIRLY COMFORTABLE DAY...ESPECIALLY CONSIDERING ALL THE EXTREME HEAT
WEVE SEEN THIS SUMMER. WEDNESDAY WILL BE SIMILARLY WARM AND
SUNNY...EXCEPT WITH MUCH LIGHTER WINDS WITH HIGH PRESSURE OVERHEAD. IF
WINDS ARENT ONSHORE TO START TO THE DAY ALONG THE LAKEFRONT...A LAKE
BREEZE SHOULD BE ABLE TO GET GOING QUICKLY WITH SUCH LIGHT FLOW OVER
THE AREA. THIS WILL AGAIN LIMIT HIGH TEMPERATURES A BIT ALONG THE
LAKESHORE.
THURSDAY PRESENTS A MORE INTERESTING SCENARIO IN TERMS OF THE HIGH
TEMPERATURE FORECAST. THE CWA WILL NOT BE IN A FAVORED AREA WITH
REGARD TO THE POSITION OF THE CENTER OF THE MIDLEVEL RIDGE...WHICH
WILL STILL BE OVER THE SOUTHERN PLAINS. HOWEVER...AN 850 MB THERMAL
RIDGE WILL PUSH INTO THE AREA WITH WARM ADVECTION BRINGING 850 MB
TEMPS TO HIGHER THAN 20C BY THE AFTERNOON...SUCH AS ON THE WELL
PERFORMING ECMWF MODEL. WITH FULL SUN AND DEEP MIXING...THIS WOULD
SUPPORT HOT TEMPERATURES IN THE MID AND UPPER 90S. HOWEVER...BOTH
THE NAM AND ECMWF...WHICH HAVE THE HOTTEST MAX TEMPS FCST...ALSO
SUGGEST FAIRLY HIGH RH AT THE MID AND UPPER LEVELS...WHICH COULD BE
IN THE FORM OF CONVECTIVE MID AND HIGH CLOUD DEBRIS. THINK CLOUDS
WILL BE THE LIMITING FACTOR FOR TEMPS ON THURSDAY...BUT WITH THE
VERY WARM THERMAL PROFILES...RAISED TEMPS A FEW DEGREES FROM
INHERITED TO MAINLY LOW 90S. IF THERE IS LESS CLOUD
COVER...CERTAINLY COULD SEE THE HOTTER TEMPS REALIZED. ALSO...WINDS
ALOFT ARE EXPECTED TO BE WEAK ENOUGH TO ALLOW FOR A LATE DAY LAKE
BREEZE TO PUSH INLAND...WHICH MAY BRING SOME MINOR COOLING.
FORCING FOR CONVECTION LOOKS RATHER WEAK AND MAINLY THURSDAY
AFTERNOON...WITH SHORT WAVE MOVING TO NORTH AND WEAK COOL FRONT
STARTING TO DROP INTO AREA...BUT WILL MAINTAIN INHERITED SLIGHT POPS
FOR NOW FOR SHRA/TSRA. MOST OF THE AREA WILL LIKELY REMAIN DRY.
RC
LONG TERM...THURSDAY EVENING THROUGH MONDAY..
SHORT WAVE MOVING THROUGH THE NORTHERN GREAT LAKES THU EVENING WITH
ASSOCIATED WEAK SURFACE TROF/FRONT DROPPING INTO NORTHERN
IL/NORTHWEST IN. WITH BEST FORCING FURTHER NORTH AND ONLY WEAK
SURFACE CONVERGENCE...AND CONSIDERING STRENGTH OF ONGOING
DROUGHT...WILL ONLY CARRY 20-30 PCT POPS. REMNANTS OF FRONT THEN
HANG UP OVER THE AREA FRIDAY BUT AGAIN WITH ONLY WEAK LOW LEVEL
CONVERGENCE AND NO UPPER LEVEL SUPPORT...WILL JUST MAINTAIN SLIGHT
CHANCE POPS FOR FRIDAY. GFS PUSHES FRONT THROUGH AND DEVELOPS EAST
WINDS OVER THE AREA FRIDAY WHILE ECMWF HAS A WEAK WISHY WASHY
SURFACE PATTERN. EITHER WAY LAKE BREEZE LIKELY TO KEEP TEMPS IN LOW
TO MID 80S LAKEFORNT BUT NEAR 90 SOUTH TOWARDS PONTIAC.
MEANWHILE MUCH MORE POTENT TROF/UPPER LOW BARRELS INTO WESTERN
CANADA COAST WED AND PLOWS THROUGH NORTHERN ROCKIES AND INTO THE
NORTHERN PLAINS THU AND FRI. THIS WILL ACT TO SHOVE UPPER RIDGE AND
ASSOCIATED HEAT DOME EASTWARD INTO THE MIDWEST AND GREAT LAKES BY
SATURDAY. SOUTHWEST FLOW AHEAD OF APPROACHING TROF PUSHES 850 TEMPS
TO AROUND 22C SATURDAY. WITH UNCERTAINTY ON CLOUD COVER HESITANT TO
RAISE TEMPS TOO MUCH. WILL GO WITH TEMPS IN LOWER 90S BUT MID TO
UPPER 90S NOT OUT OF THE QUESTION IF WE GET ENOUGH SUN. BEST CHANCE
OF WIDESPREAD RAIN IN A LONG TIME SAT AFTN AND EVENING AS STRONG
UPPER TROF/UPPER LOW MOVES THROUGH THE GREAT LAKES AND STRONG COLD
FRONT PUSHES THROUGH THE AREA. 12Z ECMWF A BITY SLOWER ON ARRIVAL OF
FRONT AND THUNDERSTORMS...MORE LIKELY SAT NIGHT INTO SUN MORNING.
TURNING COOLER AND DRIER SUN AND MON.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* PSBL SHRA/ISO TSRA AFT 03Z...THRU 09Z.
* SOUTH/SOUTHWEST WINDS...PSBL BACK SOUTHEAST THEN VEER
WEST/NORTHWEST ARND DAYBREAK TUE.
BEACHLER
//DISCUSSION...UPDATED 00Z...
VISIBLE IMAGERY EARLY THIS EVENING SHOWS THUNDERSTOMS BLOSSOMING
ALONG THE FRONTAL BOUNDARY THAT HAS PUSHED INTO NORTHEAST
WISC/UPPER PENINSULA OF MI...WITH A TRAILING FRONTAL BOUNDARY
STRETCHING SOUTHWEST THROUGH FAR NORTHEAST IA. WINDS HAVE
REMAINED SLIGHTLY SOUTHWEST...AND GUIDANCE IS INDICATING WINDS
BACK BACK TO THE SOUTHEAST BEFORE THE BOUNDARY ARRIVES LATER
TONIGHT. GUIDANCE HAS ALSO BACKED OFF ON THE TIMING/PLACEMENT OF
THE SHRA/TSRA...AND A FEW GUIDANCE MEMBERS EVEN SUGGEST VERY
MINIMAL PRECIP WILL OCCUR WITH FRONTAL PASSAGE. WHICH COMPLICATES
THE TAF FORECAST. NONETHELESS HAVE OPTED TO MAINTAIN A DRY
FORECAST...AND WILL CONTINUE TO MONITOR. ONCE THE BOUNDARY PUSHES
THROUGH THE AIRFIELDS...WINDS WILL VEER WEST/NORTHWEST. MID-LVL
CLOUDS WILL CONTINUE TO LINGER BEHIND THE FRONTAL BOUNDARY. THEN
WINDS VEER NORTHEAST LATE TUE MORNING.
WINDS MAY CONTINUE TO VEER NORTHEAST/EAST WITH A POSSIBLE LAKE
BREEZE TUE AFTN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN LAKE BREEZE REMAINING EAST OF MDW/ORD.
* MEDIUM CONFIDENCE IN POTENTIAL FOR SHRA/TSRA.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY THROUGH SATURDAY...VFR. CHC SHRA/TSRA W/PATCHY MVFR CIGS.
SUNDAY...VFR.
BEACHLER
&&
.MARINE...
226 PM CDT
LOW PRESSURE MOVING ACROSS SOUTHERN ONTARIO...WILL DRAG A COLD FRONT
DOWN THE LAKE TONIGHT. SOME STRONG TO SEVERE THUNDERSTORMS COULD
OCCUR ACROSS THE LAKE THIS EVENING AHEAD OF THE FRONT. ONCE THE
FRONT PASSES THE WINDS WILL SWITCH OUT OF THE NORTH UP TO 25 KT.
THESE STRONGER WINDS WILL CONTINUE ACROSS THE SOUTH HALF OF THE LAKE
DURING THE DAY ON TUESDAY. WAVES OVER 4 FEET ARE POSSIBLE ALONG THE
INDIANA NEAR SHORE WATERS. THIS COULD RESULT IN HAZARDS TO SMALL
CRAFT FOR TUESDAY EVENING THROUGH WEDNESDAY MORNING. HIGH PRESSURE
WILL BUILD IN ACROSS THE LAKE TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL RESULT IN ABATING WINDS FOR A PERIOD TUESDAY NIGHT INTO
WEDNESDAY.
THE WINDS LOOK TO TURN SOUTHERLY AT 10 TO 20 KT AGAIN BY THURSDAY AS
THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO VALLEY. ANOTHER
AREA OF LOW PRESSURE MAY PUSH ANOTHER COLD FRONT ACROSS THE LAKE
LATE THURSDAY AND THURSDAY NIGHT...BRINGING ANOTHER PUSH OF NORTHERLY
FLOW DOWN THE LAKE. IN THE EXTENDED PERIOD IT APPEARS THAT A
STRONGER STORM SYSTEM MAY MOVE ACROSS THE UPPER MIDWEST AND GREAT
LAKES REGION OVER THE WEEKEND. THIS COULD PRODUCE A PERIOD OF
STRONGER WINDS ACROSS THE LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ014...10 AM TUESDAY TO 10 AM
WEDNESDAY.
IN...HIGH RIP CURRENT RISK...INZ001-INZ002...10 AM TUESDAY TO 10 AM
WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...4 PM
TUESDAY TO 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1258 PM CDT SUN JUL 29 2012
.DISCUSSION...
ISSUED 1045 AM CDT SUN JUL 29 2012
FORECAST LOOKS FAIRLY GOOD TODAY AND JUST A FEW ADJUSTMENTS NEEDED
LIKE INCREASING CLOUD COVER A BIT MORE SIMILAR TO YESTERDAY WITH
PARTLY TO MOSTLY CLOUDY SKIES OVERALL. HIGHS IN THE MID TO UPPER 80S
WITH LOWER 90S OVER SW AREAS. CONTINUED 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON WHILE KEEPING AREAS EAST OF I-57
DRY. NAM AND HRRR MODELS IN BETTER AGREEMENT WITH SOME QPF OVER
WESTERN AREAS THIS AFTERNOON AND THIS IS SUPPORTED BY CURRENT FORECAST.
MOST SHOWERS AND ISOLATED THUNDERSTORMS STAYED SW OF CENTRAL IL
THIS MORNING OVER SW IL INTO EASTERN MO AND DRIFTING SE INTO THE
MID MS VALLEY. WEAK LOW PRESSURE 1013 MB NEAR THE IA/NE BORDER TO
TRACK SE TOWARD ST LOUIS BY 12Z/MON AND TO REDEVELOP ISOLATED TO
SCATTERED CONVECTION THIS AFTERNOON AND INTO TONIGHT OVER WESTERN
AREAS. SPC HAS 5% RISK OF SEVERE STORMS OVER WESTERN AREAS LATER
THIS AFTERNOON AND EVENING.
KH
&&
.AVIATION...
ISSUED 1255 PM CDT SUN JUL 29 2012
TRICKY FORECAST WITH CONVECTION CHANCES NEXT 24 HOURS BUT BEST
CHANCES APPEAR IN MORE UNSTABLE AIR MASS IN SW/WEST CENTRAL IL AT
SPI FROM MID AFTERNOON UNTIL SUNSET AND MAINTAINED VCTS THERE.
ALSO HAVE BULK SHEAR OF 40 KTS IN THIS AREA WHERE SPC NOW HAS A
SLIGHT RISK OF SEVERE STORMS FROM MID AFTEROON UNTIL SUNSET WEST
OF A GALESBURG TO CANTON TO SPRINGFIELD LINE. ALSO KEPT VCSH AT
DEC FROM 22Z-02Z. GENERALLY KEPT VFR CONDITIONS GOING ACROSS THE
CENTRAL IL TAF SITES WITH CEILINGS 4-6K FT POSSIBLE AT TIMES. IF A
THUNDERSTORM DOES OCCUR...VSBY COULD BRIEFLY GET MVFR OR LOWER. WEAK
LOW PRESSURE 1012 MB NEAR THE IA/NE BORDER AND NE KS HAS WARM
FRONT EXTENDING THROUGH CENTRAL IA/IL SOUTH OF I-74 AS SE WINDS
TURN SOUTH IN WARM SECTOR. MODELS TAKE WEAK LOW PRESSURE SE INTO
SE MO/SW IL BY 18Z/MON. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP DURING THIS AFTERNOON AND INTO THIS
EVENING OVER MAINLY WESTERN/SW AREAS CLOSER TO LOW PRESSURE
SYSTEM. ALSO HAVE AREA OF SHOWERS OVER SW WI...NW IL AND FAR NE
IOWA THAT IS MOVING ESE AND COULD GET CLOSE TO CMI DURING TONIGHT.
SSE WINDS 8-13 KTS THIS AFTERNOON TO BE SE 6-8 KTS TONIGHT AND SE
AROUND 10 KTS MON MORNING.
KH
&&
.PREV DISCUSSION...
ISSUED 254 AM CDT SUN JUL 29 2012
AT 06Z HIGH PRESSURE STILL OCCUPIED THE GREAT LAKES AND THIS
PROVIDED A CALM AND SEASONABLE NIGHT ACROSS CENTRAL IL. FARTHER
WEST POORLY ORGANIZED BROAD LOW PRESSURE STRETCHED ACROSS THE
CENTRAL PLAINS. ALOFT...NORTHWEST FLOW DOMINATED MUCH OF THE
MIDWEST. CONVECTION AS CLOSE AS SE IA/NE MO WAS OCCURRING AHEAD OF
A SHORTWAVE DROPPING INTO SW MN...AND ALONG A MID LEVEL THETA-E
GRADIENT AND AREA OF 850MB MOISTURE CONVERGENCE. AS THIS AREA OF
LIFT AND CONVERGENCE SHIFTS SOUTHEAST TODAY THUNDERSTORM CHANCES
WILL RETURN TO THE FORECAST.
SHORT TERM...TODAY THROUGH MONDAY
EXPECT SCATTERED CONVECTION TO PUSH INTO THE WESTERN CWA AFTER SUNRISE
AND GRADUALLY DIMINISH THROUGH THE MORNING AS MID LEVEL CONVERGENCE
WANES. THEREFORE HAVE HIGHEST POPS IN THE FAR WEST QUICKLY
TAPERING TO SLIGHT CHANCE FOR THE CENTRAL AND EASTERN CWA. LIFT
AHEAD OF THE SHORTWAVE DROPPING IN FROM THE NORTHWEST COULD KEEP
ISOLATED TO SCATTERED CONVECTION GOING INTO THE AFTERNOON BUT DO
NOT ANTICIPATE HIGH COVERAGE. WHILE INSTABILITY IS LIMITED /MUCAPES
700-900 J/KG/...SHEAR IS MORE IMPRESSIVE DUE TO SOUTHERLY SURFACE
WINDS AND WESTERLY FLOW ALOFT WHICH CONTRIBUTES TO 40 KTS OF BULK
SHEAR. SO SOME THUNDERSTORM ORGANIZATION IS POSSIBLE WITH STRONGER
CELLS CAPABLE OF SMALL HAIL OR BRIEF GUSTY WINDS...MOST FAVORED IN
THE SOUTHWEST CWA. WITH THE LIKELIHOOD OF INCREASED CLOUD COVER
WILL TAKE A FEW DEGREES OFF MET GUIDANCE...FOR HIGHS IN THE UPPER
80S TO LOWER 90S.
AS HAS BEEN THE CASE THE PAST COUPLE DAYS TO OUR NORTHWEST...THE
AREA OF LIFT VERY SLOWLY DRIFTS SOUTHEAST SO WILL MAINTAIN LOW
CHANCE POPS FOR AREAS EAST OF THE IL RIVER SUNDAY NIGHT...AND THE
SOUTHEAST THIRD INTO MONDAY MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY
BEHIND THE DEPARTING SYSTEM...HIGH PRESSURE BUILDING INTO THE
GREAT LAKES PROVIDES LIGHT NORTHERLY FLOW INTO MID-WEEK. 850 MB
TEMPS REMAIN QUITE WARM...ABOVE 20C SO WILL KEEP TEMPS A FEW
DEGREES ABOVE NORMAL. INTERESTING THAT MET GUIDANCE ALREADY PUSHES
HIGHS ABOVE 100 BY TUESDAY FOR SOUTHERN HALF OF THE AREA...BUT
GIVEN LIGHT FLOW/LIMITED MIXING WILL KNOCK A FEW DEGREES OFF
THESE NUMBERS.
NORTHWEST FLOW ALOFT CONTINUES TO DOMINATE THE WEATHER PATTERN
THROUGH THE REMAINDER OF THE EXTENDED FORECAST. DUE TO MODEL
DIFFERENCES IN TIMING AND LOCATION OF ANY SHORTWAVES...AND RECENT
TRENDS/DROUGHT WILL KEEP THE FORECAST DRY UNTIL A MORE SUBSTANTIAL
TROUGH SHIFTS INTO THE GREAT LAKES TOWARDS SATURDAY. TEMPERATURES
LOOK TO STAY SEVERAL DEGREES ABOVE NORMAL INTO NEXT WEEKEND.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT SUN JUL 29 2012
.DISCUSSION...
ISSUED 1045 AM CDT SUN JUL 29 2012
FORECAST LOOKS FAIRLY GOOD TODAY AND JUST A FEW ADJUSTMENTS NEEDED
LIKE INCREASING CLOUD COVER A BIT MORE SIMILAR TO YESTERDAY WITH
PARTLY TO MOSTLY CLOUDY SKIES OVERALL. HIGHS IN THE MID TO UPPER 80S
WITH LOWER 90S OVER SW AREAS. CONTINUED 20-40% CHANCE OF SHOWERS
AND THUNDERSTORMS THIS AFTERNOON WHILE KEEPING AREAS EAST OF I-57
DRY. NAM AND HRRR MODELS IN BETTER AGREEMENT WITH SOME QPF OVER
WESTERN AREAS THIS AFTERNOON AND THIS IS SUPPORTED BY CURRENT FORECAST.
MOST SHOWERS AND ISOLATED THUNDERSTORMS STAYED SW OF CENTRAL IL
THIS MORNING OVER SW IL INTO EASTERN MO AND DRIFTING SE INTO THE
MID MS VALLEY. WEAK LOW PRESSURE 1013 MB NEAR THE IA/NE BORDER TO
TRACK SE TOWARD ST LOUIS BY 12Z/MON AND TO REDEVELOP ISOLATED TO
SCATTERED CONVECTION THIS AFTERNOON AND INTO TONIGHT OVER WESTERN
AREAS. SPC HAS 5% RISK OF SEVERE STORMS OVER WESTERN AREAS LATER
THIS AFTERNOON AND EVENING.
KH
&&
.AVIATION...
ISSUED 605 AM CDT SUN JUL 29 2012
DESPITE AN AREA OF SHOWERS APPROACHING FROM THE WEST THIS
MORNING...WE ARE STILL EXPECTING VFR CONDITIONS THROUGH THIS
FORECAST PERIOD (THRU 12Z MONDAY). JUST HOW FAR EAST THE RAIN
WILL GET THIS MORNING IS THE MAIN FORECAST CHALLENGE EARLY ON IN
THIS FORECAST...AND THEN WHETHER OR NOT WE WILL SEE ANY REDEVELOPMENT
LATER THIS AFTN AND EVENING AS A WEATHER SYSTEM SLOWLY PUSHES ACRS
THE AREA. AREAS OUT TO OUR WEST WHERE IT HAS BEEN RAINING FOR A
WHILE STILL ARE REPORTING VFR CIGS WITH BASES AVERAGING FROM
7000-10000 FEET. BASED ON THE LATEST SHORT TERM MODEL RUNS...WILL
CONTINUE TO INCLUDE THE SHOWER CHANCES IN THE TAFS FOR SPI AND PIA
ONLY AND WAIT AND SEE IF THE RAIN CAN ADVANCE ANY FURTHER EAST.
AFTER THIS BATCH OF PRECIP WINDS DOWN...WILL HOLD OFF INCLUDING
ANYTHING OTHER THAN A VCTS AND CB GROUP AT SPI AND DEC LATE THIS
AFTN AND EVENING AS THOSE TWO SITES WILL BE CLOSER TO THE MORE
UNSTABLE AIR MASS WHICH WILL BE ACRS NE MO INTO EXTREME SW IL.
SURFACE WINDS WILL VEER INTO A SOUTHERLY DIRECTION TODAY AT 10 TO
15 KTS...WITH POSSIBLY A FEW GUSTS TO NEAR 20 KTS...ESP AT PIA AND
SPI WHICH WILL BE CLOSER TO THE RAIN THIS MORNING. WINDS ARE THEN
EXPECTED TO BACK INTO MORE OF A SOUTHEAST DIRECTION TONIGHT AT 5
TO 10 KTS.
SMITH
&&
.PREV DISCUSSION...
ISSUED 254 AM CDT SUN JUL 29 2012
AT 06Z HIGH PRESSURE STILL OCCUPIED THE GREAT LAKES AND THIS
PROVIDED A CALM AND SEASONABLE NIGHT ACROSS CENTRAL IL. FARTHER
WEST POORLY ORGANIZED BROAD LOW PRESSURE STRETCHED ACROSS THE
CENTRAL PLAINS. ALOFT...NORTHWEST FLOW DOMINATED MUCH OF THE
MIDWEST. CONVECTION AS CLOSE AS SE IA/NE MO WAS OCCURRING AHEAD OF A
SHORTWAVE DROPPING INTO SW MN...AND ALONG A MID LEVEL THETA-E
GRADIENT AND AREA OF 850MB MOISTURE CONVERGENCE. AS THIS AREA OF
LIFT AND CONVERGENCE SHIFTS SOUTHEAST TODAY THUNDERSTORM CHANCES
WILL RETURN TO THE FORECAST.
SHORT TERM...TODAY THROUGH MONDAY
EXPECT SCATTERED CONVECTION TO PUSH INTO THE WESTERN CWA AFTER SUNRISE
AND GRADUALLY DIMINISH THROUGH THE MORNING AS MID LEVEL CONVERGENCE
WANES. THEREFORE HAVE HIGHEST POPS IN THE FAR WEST QUICKLY
TAPERING TO SLIGHT CHANCE FOR THE CENTRAL AND EASTERN CWA. LIFT
AHEAD OF THE SHORTWAVE DROPPING IN FROM THE NORTHWEST COULD KEEP
ISOLATED TO SCATTERED CONVECTION GOING INTO THE AFTERNOON BUT DO
NOT ANTICIPATE HIGH COVERAGE. WHILE INSTABILITY IS LIMITED /MUCAPES
700-900 J/KG/...SHEAR IS MORE IMPRESSIVE DUE TO SOUTHERLY SURFACE
WINDS AND WESTERLY FLOW ALOFT WHICH CONTRIBUTES TO 40 KTS OF BULK
SHEAR. SO SOME THUNDERSTORM ORGANIZATION IS POSSIBLE WITH STRONGER
CELLS CAPABLE OF SMALL HAIL OR BRIEF GUSTY WINDS...MOST FAVORED IN
THE SOUTHWEST CWA. WITH THE LIKELIHOOD OF INCREASED CLOUD COVER
WILL TAKE A FEW DEGREES OFF MET GUIDANCE...FOR HIGHS IN THE UPPER
80S TO LOWER 90S.
AS HAS BEEN THE CASE THE PAST COUPLE DAYS TO OUR NORTHWEST...THE
AREA OF LIFT VERY SLOWLY DRIFTS SOUTHEAST SO WILL MAINTAIN LOW
CHANCE POPS FOR AREAS EAST OF THE IL RIVER SUNDAY NIGHT...AND THE
SOUTHEAST THIRD INTO MONDAY MORNING.
LONG TERM...TUESDAY THROUGH SATURDAY
BEHIND THE DEPARTING SYSTEM...HIGH PRESSURE BUILDING INTO THE
GREAT LAKES PROVIDES LIGHT NORTHERLY FLOW INTO MID-WEEK. 850 MB
TEMPS REMAIN QUITE WARM...ABOVE 20C SO WILL KEEP TEMPS A FEW
DEGREES ABOVE NORMAL. INTERESTING THAT MET GUIDANCE ALREADY PUSHES
HIGHS ABOVE 100 BY TUESDAY FOR SOUTHERN HALF OF THE AREA...BUT
GIVEN LIGHT FLOW/LIMITED MIXING WILL KNOCK A FEW DEGREES OFF
THESE NUMBERS.
NORTHWEST FLOW ALOFT CONTINUES TO DOMINATE THE WEATHER PATTERN
THROUGH THE REMAINDER OF THE EXTENDED FORECAST. DUE TO MODEL
DIFFERENCES IN TIMING AND LOCATION OF ANY SHORTWAVES...AND RECENT
TRENDS/DROUGHT WILL KEEP THE FORECAST DRY UNTIL A MORE SUBSTANTIAL
TROUGH SHIFTS INTO THE GREAT LAKES TOWARDS SATURDAY. TEMPERATURES
LOOK TO STAY SEVERAL DEGREES ABOVE NORMAL INTO NEXT WEEKEND.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1243 PM CDT SUN JUL 29 2012
.UPDATE...
BAND OF SHOWERS CONTINUES TO DISSIPATE THIS AFTERNOON AS IT
OUTRUNS THE SHORTWAVE THAT GENERATED IT...AND THE LOW LEVEL JET
WEAKENS AND BACKS ONCE AGAIN TO THE WEST. HOWEVER...ACROSS THE
SOUTHWEST HALF OF THE FORECAST AREA WE HAVE FULL SUNSHINE AND
PLENTY OF AVAILABLE MOISTURE TO BUILD INSTABILITY WITH. AM
CONCERNED ABOUT A CAP THAT MAY SUPPRESS ANY CONVECTIVE INITIATION.
MODELS WERE TOO WARM AT MID LEVELS AS COMPARED TO THIS MORNINGS
SOUNDING...SO ANTICIPATE THAT IT MAY BE EASIER TO GET CONVECTION
GOING THAN MOST OF THE MODELS HAVE IMPLIED. THE HRRR DOES SHOW
CONVECTION DEVELOPING THIS AFTERNOON IN A LINE EXTENDING FROM KMLI
BACK TO KMIW...AND THEN DROPPING SOUTHEAST DURING THE AFTERNOON.
MODEL SOUNDINGS IMPLY THAT OUR CONVECTIVE TEMPERATURE SHOULD BE IN
THE LOW TO MID 80S...SO WILL NEED TO KEEP AN EYE OUT FOR THIS IN
THE NEXT FEW HOURS. HAVE MADE SOME OTHER UPDATES TO FRESHEN UP
TEMPERATURES...DEWPOINTS...WINDS AND SKY COVER AS WELL AS THE
ABOVE DISCUSSED ADJUSTMENT FOR POPS.
&&
.AVIATION...
VFR CONDITIONS CONTINUE AT ALL TAF SITES. LIGHT RAIN SHOWERS TO
CLEAR KDBQ IN THE NEXT HOUR. NEW CONVECTION ANTICIPATED WHICH MAY
AFFECT KCID...KMLI AND POSSIBLY KBRL THIS AFTERNOON. THESE MAY
BRING MVFR CIGS AND VSBYS WITH GUSTY WINDS...BUT HAVE KEPT THINGS
TO VCTS IN TERMINALS DUE TO UNCERTAINTIES WITH TIMING AND SPECIFIC
LOCATION. ALL CONVECTION SHOULD CLEAR THE TERMINALS BY 00Z THIS
EVENING AND THEN WE WILL RETURN TO VFR CONDITIONS EVERYWHERE FOR
THE REMAINDER OF THE TAF PERIOD. LIGHT SOUTHEAST WINDS THIS
AFTERNOON TO GRADUALLY NORTHEAST LATE THIS AFTERNOON AND
EVENING...TO THEN CONTINUE INTO MONDAY MORNING.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
LE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
611 PM CDT MON JUL 30 2012
...UPDATED FOR AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1158 AM CDT MON JUL 30 2012
AN UPPER LEVEL HIGH CONTINUED TO GRIP THE CENTRAL AND SOUTHERN GREAT
PLAINS. THE CENTER OF THE HIGH AT 500MB WAS LOCATED ACROSS THE
SOUTHERN TEXAS PANHANDLE PER RAOB AND RAP ANALYSIS AS OF 30.12Z. AN
ARC OF MID LEVEL MOISTURE COULD BE SEEN ON WATER VAPOR LOOP AND RAOB
ANALYSIS FROM WESTERN/CENTRAL ARIZONA THROUGH UTAH AND NORTHEAST TO
SOUTHEASTERN WYOMING AND WESTERN NEBRASKA. ALL ALONG THIS MOISTURE
ARC...THERE WERE MINOR MID LEVEL PERTURBATIONS IN THE FLOW PATTERN
DUE TO LATENT HEAT RELEASE FROM VARIOUS THUNDERSTORM CLUSTERS. A
MESOSCALE CONVECTIVE SYSTEM MOVED ACROSS SOUTHERN NEBRASKA/NORTHERN
KANSAS DURING THE OVERNIGHT HOURS WITH THE MID LEVEL POTENTIAL
VORTICITY ANOMALY TIED TO THIS MCS MOVING INTO EASTERN KS/WESTERN
MO. ADDITIONAL MID LEVEL VORTICITY COULD BE SEEN IN THE RAP ANALYSIS
MOVING INTO NORTHERN COLORADO WITH A 30-40 KNOT 400MB SPEED MAX
ROTATING NORTH-NORTHEASTWARD INTO THE COLORADO ROCKIES. IN THE LOWER
TROPOSPHERE...A STATIONARY FRONT EXTENDED FROM ROUGHLY BEAVER, OK TO
BUCKLIN, KS TO NEAR PRATT, KS AT 16Z. OKLAHOMA MESONET OBSERVATIONS
AT 1650Z REVEALED AN AXIS OF 102 TO 104F TEMPERATURES ACROSS
WEST-CENTRAL OKLAHOMA ON WEST-SOUTHWEST SURFACE WINDS SOUTH OF THIS
BOUNDARY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 244 PM CDT MON JUL 30 2012
WITH THE AFTERNOON FORECAST UPDATE...WILL LOWER THE POPS DOWN TO
10-14 PERCENT FOR AREAS ALONG THE STATIONARY FRONT AS CONVERGENCE
ALONG THE FRONT IS QUITE WEAK AND THERE HAS BEEN A LACK OF CUMULUS
DEVELOPMENT THROUGH 1930Z. IF ANYTHING DOES DEVELOP...THE COVERAGE
WILL BE VERY ISOLATED AND ANY INDIVIDUAL STORM WILL BE SMALL. WILL
BE TURNING THE ATTENTION TO THE WEST LATER ON THIS EVENING AND
DURING THE OVERNIGHT HOURS AS AN MCS MAY DEVELOP IN THE POST-FRONTAL
LIGHT UPSLOPE WINDS WITH DEWPOINTS IN THE MID TO UPPER 50S ACROSS
EAST-CENTRAL COLORADO AND WEST-CENTRAL/SOUTHWEST KANSAS ALONG AND
NORTH OF THE FRONT. VARIOUS HIGH-RESOLUTION CONVECTION-ALLOWING
MODELS SUGGEST HIGHER TERRAIN STORMS WILL MANAGE TO HOLD TOGETHER TO
THE KANSAS STATE BORDER...SO WILL HAVE 30 POPS GOING ACROSS THE
WESTERN COUNTIES AND 20 POPS AS FAR EAST AS ROUGHLY HIGHWAY 83.
LATE TONIGHT INTO TOMORROW...THE CONVECTIVE OUTFLOW FROM WHATEVER
REMAINS OF THE MCS TONIGHT WILL PUSH THE STATIONARY FRONT FARTHER
SOUTH THAN WHERE IT IS NOW WITH A WEAK WAVE DEVELOPING ALONG THE
FRONT ACROSS SOUTH-CENTRAL KS BY DAYBREAK TUESDAY. WEST OF THE
WAVE...WINDS AT THE SURFACE WILL LIKELY BE MORE NORTHERLY ACROSS
MUCH OF THE DDC FORECAST AREA. TOMORROW`S FORECAST HIGH TEMPERATURE
HAS BEEN LOWERED TO MID-UPPER 90S FROM HAYS TO CIMARRON TO HUGOTON
AND POINTS WEST TO THE COLORADO BORDER. EVEN THE AREAS ACROSS SOUTH
CENTRAL KANSAS WILL BE SLIGHTLY NORTH OF THE FRONT MORE THAN LIKELY
AND HAVE LOWERED THE HIGHS IN MEDICINE LODGE AREA DOWN TO ABOUT
103-104F (WHICH MAY STILL BE A BIT TOO WARM IF THE FRONT ENDS UP
BEING JUST SOUTH OF THERE). AS FAR AS THUNDERSTORM POTENTIAL GOES
TOMORROW...IT WILL BE VERY SIMILAR TO TODAY...WITH THE GENERAL
THINKING BEING THAT ANYTHING THAT WOULD DEVELOP ALONG THE FRONT
WOULD BE VERY ISOLATED IN NATURE WITH THE MOST COHERENT CONVECTION
FORMING ONCE AGAIN OVER EASTERN COLORADO. WILL BE KEEPING POPS BELOW
15 EXCEPT NEAR THE COLORADO BORDER FOR LATE IN THE AFTERNOON TUESDAY
AS A RESULT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 336 PM CDT MON JUL 30 2012
AN UPPER LEVEL RIDGE WILL REMAIN ACROSS THE SOUTHERN PLAINS
WEDNESDAY AND THURSDAY, WITH WESTERN KANSAS LOCATED ALONG THE
SOUTHERN EDGE OF THE WESTERLIES NEAR A QUASI-STATIONARY SURFACE
FRONT. ORDINARILY THIS KIND OF PATTERN COULD RESULT IN ISOLATED
THUNDERSTORMS. BUT THIS YEAR THE LOW-LEVEL MOISTURE IS JUST VERY
LIMITED. NEVERTHELESS, ISOLATED THUNDERSTORMS CANNOT BE RULED OUT
EITHER DAY. TEMPERATURES WILL CONTINUE TO BE HOT, ESPECIALLY
SOUTH OF THE FRONT OVER SOUTH CENTRAL AND PARTS OF SOUTHWEST
KANSAS TO THE SOUTH OF THE FRONT.
ALTHOUGH THERE ARE SLIGHT DIFFERENCES IN MODEL TIMING, A STRONG
SHORTWAVE TROUGH IS ADVERTISED TO DIG INTO THE NORTHERN ROCKIES
FRIDAY AND THEN PASS ACROSS THE NORTHERN PLAINS BY SATURDAY.
AN OLD FRONT WILL STILL BE STALLED OUT ACROSS SOUTHWEST KANSAS, AND
A REINFORCING COLD FRONT WILL APPROACH KANSAS WITH THE NORTHERN
STREAM SYSTEM BY SATURDAY OR SATURDAY NIGHT. THERE WILL BE ADDITIONAL
SMALL CHANCES FOR THUNDERSTORMS EACH DAY, WITH THE EXACT LOCATION
DEPENDING ON WHERE THE FRONTAL BOUNDARIES ARE. IT WILL STILL BE HOT,
ESPECIALLY SOUTH OF THE FRONTS OVER SOUTH CENTRAL KANSAS, WITH HIGHS
ABOVE 105F FOR BOTH FRIDAY AND SATURDAY. SLIGHTLY COOLER TEMPERATURES
CAN BE EXPECTED IN WEST CENTRAL KANSAS. SLIGHTLY COOLER
TEMPERATURES ARE EXPECTED BY SUNDAY AND MONDAY ACROSS MOST OF
SOUTHWEST KANSAS AFTER THE AFOREMENTIONED SHORTWAVE TROUGH PUSHES
A COLD FRONT THROUGH KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 611 PM CDT MON JUL 30 2012
THE WEAK STATIONARY FRONT ACROSS SOUTHERN KANSAS WILL PERSIST
THROUGH TOMORROW, WITH THE BEST MOISTURE AND CHANCES OF
THUNDERSTORM DEVELOPMENT OFF TO OUR SOUTHEAST. SOME THUNDERSTORM
ACTIVITY HAS DEVELOPED IN NORTHEAST COLORADO, BUT ACROSS
SOUTHEASTERN COLORADO DEVELOPMENT HAS BEEN MUCH LESS THAN THE
SHORT TERM HIGH RESOLUTION MODELS HAVE INDICATED, SO HAVE ELECTED
TO DROP THE MENTION OF ANY THUNDERSTORMS AT GCK.
&
.PRELIMINARY POINT TEMPS/POPS...
DDC 72 100 75 104 / 10 10 20 10
GCK 71 96 73 103 / 20 10 20 20
EHA 70 98 73 103 / 30 20 20 20
LBL 71 99 74 104 / 20 10 20 10
HYS 71 98 75 103 / 10 10 20 10
P28 75 104 78 108 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...WOLFE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
213 PM MDT SUN JUL 29 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 120 PM MDT SUN JUL 29 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE CONTINUING TO
DOMINATE US PATTERN WITH CENTER OVER NORTHERN TEXAS. ALONG THE
WEST/NORTHWEST EXTENT OF THE RIDGE MONSOONAL MOISTURE CONTINUES TO
STREAM NORTH ACROSS THE INTER-MOUNTAIN WEST TOWARDS THE CWA. AT THE
SURFACE A LINGERING BAROCLINIC ZONE/DECAYED STATIONARY FRONT REMAINS
IN PLACE OVER THE CWA.
EARLY MORNING SHOWERS HAVE MOVED OFF TO THE EAST...WITH CLEARING
OCCURRING TO THE SOUTH AND WEST. MIXED LAYER CAPE VALUES ACROSS THE
AREA ARE CURRENTLY IN THE 500-1500 J/KG RANGE AND SHOULD INCREASE
WITH CLEARING AS LOW LEVEL LAPSE RATES STEEPEN. A WEAK SHORTWAVE
TROUGH IS PROGGED TO MOVE ACROSS SW NEBRASKA...AND MAY BE THE
FEATURE THAT HELPS GET THINGS GOING AGAIN TONIGHT. THE LATEST HRRR
WOULD INDICATE THAT THUNDERSTORM REDEVELOPMENT LIKELY WILL HOLD OFF
UNTIL AFTER 00Z...HOWEVER IT IS DEVELOPING WIDESPREAD CONVECTION
FURTHER SOUTH THAN WHAT THE LATEST NAM/GFS WOULD INDICATE...SO HAVE
KEPT POPS IN CHANCE CATEGORY THIS EVENING/OVERNIGHT. OVERALL SHEAR
IS WEAK AND THERE IS VERY LITTLE TO GET STORMS MOVING IN PROXIMITY
TO BAROCLINIC ZONE. WITH VERY HIGH PWAT VALUES IN EXCESS OF 1.5
HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE WITH THESE SLOW
MOVING THUNDERSTORMS. AS WITH YESTERDAY COVERAGE IS STILL A
QUESTION...WITH BEST COVERAGE RIGHT NOW EXPECTED TO BE ACROSS THE
NORTHERN HALF OTHER CWA OVERNIGHT IN PROXIMITY TO SHORTWAVE TROUGH.
WITH BAROCLINIC ZONE IN PLACE THROUGH MONDAY SHOWERS/THUNDERSTORMS
COULDNT BE RULED OUT THROUGH MONDAY AFTERNOON AS WEAK PULSES
CONTINUE TO MOVE WITHIN PROXIMITY OF THE CWA.
TEMPERATURES SHOULD BE COOLER ON MONDAY AFTERNOON HIGHS IN THE MID
TO UPPER 90S ACROSS THE CWA. EASTERLY FLOW WILL DEVELOP ACROSS THE
REGION...AND H85 TEMPS WILL MODERATE SOME WITH VALUES ABOUT 3C COOLER.
DEPENDING ON CLOUD COVER SOME LOCATIONS COULD SEE HIGHS ON MONDAY
CLOSER TO NORMAL VALUES IN THE LOW 90S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 205 PM MDT SUN JUL 29 2012
RIDGE OVER THE SOUTHERN PLAINS WILL DRIFT WESTWARD. TEMPERATURES
WILL CONTINUE TO BE ABOVE NORMAL. THE RIDGE IS FAR ENOUGH SOUTH
THAT SHORTWAVE TROUGHS COMING OVER THE TOP WILL BRING OCCASIONAL
CHANCES FOR THUNDERSTORMS. MODELS HINTING AT FAIRLY STRONG ONE
TUESDAY NIGHT WITH POSSIBLE MCS DEVELOPING IN EASTERN COLORADO AND
MOVING ACROSS THE FORECAST AREA. BUMPED POPS UP TO
CHANCE...ESPECIALLY IN THE WEST. THE PATTERN BASICALLY REPEATS
THROUGH THE END OF THE WEEK...SO COULD END UP WITH A RATHER WET
PATTERN. STRONG SYSTEM WILL MOVE ACROSS THE NORTHERN PLAINS ON
FRIDAY AND DRIVE A COLD FRONT THROUGH THE AREA. COOLER
TEMPERATURES FOLLOW ON SATURDAY...AT LEAST CLOSER TO NORMAL.
DESPITE THE POST FRONTAL UPSLOPE AT THE SURFACE...SHORTWAVE
RIDGING IS FORECAST OVER THE WEEKEND...SO THINK PRECIPITATION
CHANCES WILL COME TO AN END.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1129 AM MDT SUN JUL 29 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. LIGHT SHOWERS ARE IN THE PROCESS OF WEAKENING
AND MOVING EAST OF BOTH TERMINALS...AND SHOULD BE GONE BY VALID
TAF TIME. AS SKIES CLEAR INSTABILITY WILL BEGIN TO INCREASE. WITH
FRONTAL ZONE STILL LINGERING BETWEEN BOTH TERMINALS THUNDERSTORMS
SHOULD BEGIN TO RE-DEVELOP BY MID AFTERNOON AND SHIFT NORTH AND
EAST ACROSS THE AREA. CONFIDENCE IS STILL TOO LOW TO ZERO IN ON AN
EXACT TIME OF OCCURRENCE AT EITHER TERMINAL...SO LEFT VCTS IN
PLACE. THUNDERSTORM ACTIVITY MAY LINGER LONGER AT KMCK THROUGH THE
NIGHT AS A WEAK SHORTWAVE MOVES ACROSS NEBRASKA. WINDS GENERALLY
BE OUT OF THE EAST/SOUTHEAST BELOW 12KT THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
121 PM MDT SUN JUL 29 2012
.SHORT TERM...(THIS EVENING THROUGH MONDAY AFTERNOON)
ISSUED AT 120 PM MDT SUN JUL 29 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE CONTINUING TO
DOMINATE US PATTERN WITH CENTER OVER NORTHERN TEXAS. ALONG THE
WEST/NORTHWEST EXTENT OF THE RIDGE MONSOONAL MOISTURE CONTINUES TO
STREAM NORTH ACROSS THE INTER-MOUNTAIN WEST TOWARDS THE CWA. AT THE
SURFACE A LINGERING BAROCLINIC ZONE/DECAYED STATIONARY FRONT REMAINS
IN PLACE OVER THE CWA.
EARLY MORNING SHOWERS HAVE MOVED OFF TO THE EAST...WITH CLEARING
OCCURRING TO THE SOUTH AND WEST. MIXED LAYER CAPE VALUES ACROSS THE
AREA ARE CURRENTLY IN THE 500-1500 J/KG RANGE AND SHOULD INCREASE
WITH CLEARING AS LOW LEVEL LAPSE RATES STEEPEN. A WEAK SHORTWAVE
TROUGH IS PROGGED TO MOVE ACROSS SW NEBRASKA...AND MAY BE THE
FEATURE THAT HELPS GET THINGS GOING AGAIN TONIGHT. THE LATEST HRRR
WOULD INDICATE THAT THUNDERSTORM REDEVELOPMENT LIKELY WILL HOLD OFF
UNTIL AFTER 00Z...HOWEVER IT IS DEVELOPING WIDESPREAD CONVECTION
FURTHER SOUTH THAN WHAT THE LATEST NAM/GFS WOULD INDICATE...SO HAVE
KEPT POPS IN CHANCE CATEGORY THIS EVENING/OVERNIGHT. OVERALL SHEAR
IS WEAK AND THERE IS VERY LITTLE TO GET STORMS MOVING IN PROXIMITY
TO BAROCLINIC ZONE. WITH VERY HIGH PWAT VALUES IN EXCESS OF 1.5
HEAVY RAIN AND LOCALIZED FLOODING WILL BE POSSIBLE WITH THESE SLOW
MOVING THUNDERSTORMS. AS WITH YESTERDAY COVERAGE IS STILL A
QUESTION...WITH BEST COVERAGE RIGHT NOW EXPECTED TO BE ACROSS THE
NORTHERN HALF OTHER CWA OVERNIGHT IN PROXIMITY TO SHORTWAVE TROUGH.
WITH BAROCLINIC ZONE IN PLACE THROUGH MONDAY SHOWERS/THUNDERSTORMS
COULDNT BE RULED OUT THROUGH MONDAY AFTERNOON AS WEAK PULSES
CONTINUE TO MOVE WITHIN PROXIMITY OF THE CWA.
TEMPERATURES SHOULD BE COOLER ON MONDAY AFTERNOON HIGHS IN THE MID
TO UPPER 90S ACROSS THE CWA. EASTERLY FLOW WILL DEVELOP ACROSS THE
REGION...AND H85 TEMPS WILL MODERATE SOME WITH VALUES ABOUT 3C COOLER.
DEPENDING ON CLOUD COVER SOME LOCATIONS COULD SEE HIGHS ON MONDAY
CLOSER TO NORMAL VALUES IN THE LOW 90S.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1129 AM MDT SUN JUL 29 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. LIGHT SHOWERS ARE IN THE PROCESS OF WEAKENING
AND MOVING EAST OF BOTH TERMINALS...AND SHOULD BE GONE BY VALID
TAF TIME. AS SKIES CLEAR INSTABILITY WILL BEGIN TO INCREASE. WITH
FRONTAL ZONE STILL LINGERING BETWEEN BOTH TERMINALS THUNDERSTORMS
SHOULD BEGIN TO RE-DEVELOP BY MID AFTERNOON AND SHIFT NORTH AND
EAST ACROSS THE AREA. CONFIDENCE IS STILL TOO LOW TO ZERO IN ON AN
EXACT TIME OF OCCURRENCE AT EITHER TERMINAL...SO LEFT VCTS IN
PLACE. THUNDERSTORM ACTIVITY MAY LINGER LONGER AT KMCK THROUGH THE
NIGHT AS A WEAK SHORTWAVE MOVES ACROSS NEBRASKA. WINDS GENERALLY
BE OUT OF THE EAST/SOUTHEAST BELOW 12KT THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER/PMM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1129 AM MDT SUN JUL 29 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MAIN FORECAST PROBLEM WILL BE PRECIPITATION CHANCES THROUGH THE
SHORT TERM. SATELLITE SHOWING THE FLOW HAS DEAMPLIFIED OVER THE LAST
24 HOURS ACROSS MOST OF THE PACIFIC. THIS FLOW THEN TRANSITIONS TO
THE UPPER TROUGH NEAR THE WEST COAST WITH PERSISTENT/BROAD UPPER
RIDGE REMAINING ANCHORED OVER THE CENTER OF THE COUNTRY. CENTER OF
THIS RIDGE HAS MOVED SOUTHEAST FROM YESTERDAY...HOWEVER THE RIDGE HAS
ELONGATED TO THE NORTHWEST.
SATELLITE/UPPER AIR ANALYSIS SHOWS STRONG SUBTROPICAL MOISTURE FEED
AROUND THE WEST AND NORTHERN PORTION OF THE HIGH. BESIDES A SMALL
INCREASE IN MID LEVEL MOISTURE...THE AIR MASS REMAINS NEARLY THE
SAME FROM YESTERDAY. AT MID LEVELS...THE GFS/UKMET WERE DOING A
LITTLE BETTER THAN THE CANADIAN/SREF WITH THE NAM INITIALIZING THE
WORST OF THE BUNCH...ESPECIALLY ON THE CENTER POSITION OF THE RIDGE.
ONGOING CONVECTION AND OUTFLOW BOUNDARIES MAKING A LITTLE HARDER TO
GET A GOOD HANDLE ON THE SURFACE. THE SREF/RUC/HRRR WERE CATCHING
BETTER THAN THE NAM AND ECMWF. MODELS WERE PRETTY CLOSE ON THE LOW
LEVEL THERMAL FIELD. THE NAM/CANADIAN/SREF WERE DOING SLIGHTLY
BETTER.
NAM THROUGH 06Z HAS PRECIPITATION COVERAGE UNDERDONE THAT WAS
OVER/NEAR THE EAST/SOUTHEAST PORTION OF THE AREA. IT PUT MORE
EMPHASIS/PRECIPITATION ON THE WESTERN END OF THE SURFACE THAN IN THE
EAST. TO SOME EXTENT ALL THE MODELS SHOW THAT BIAS. THE SREF AND TO
A LESSER EXTENT THE CANADIAN GOT THAT PRECIPITATION RIGHT. FROM
YESTERDAY...THE RUC AND HRRR STARTED THE PRECIPITATION FURTHER NORTH
AND EAST AND WAS THE MOST CORRECT. THE HRRR TONIGHT IS CATCHING THE
CURRENT PRECIPITATION AREA IN THE EAST WELL.
TODAY/TONIGHT...OVERNIGHT CONVECTION WILL PROBABLY LEAVE AROUND
LEFTOVER BOUNDARIES. MOST MODELS ARE INSISTENT OF STARTING CONVECTION
BY 18Z. SURFACE BOUNDARY NEAR THE SOUTHERN PORTION OF THE AREA WITH
A WEAK SHORTWAVE TROUGH NEAR THE WESTERN PORTION OF THE AREA AT THE
BEGINNING OF THE DAY AS WELL. MODELS HAVE BEEN SIMILAR IN HAVING
THE BEST CHANCE OF PRECIPITATION IN THE WEST AND NORTHERN PORTION OF
THE AREA. SREF AND GEFS PROBABILITIES MATCH UP WHERE THE DEEPEST
LIFT IS. SO ADJUSTED THE CHANCE POPS FURTHER EAST.
MODELS STILL SHOWING IT WARM TODAY. KEPT IT CLOSE TO WHAT THE
WARMEST GUIDANCE WHICH WAS CLOSE TO THE PREVIOUS FORECAST.
MONDAY...THERE LOOKS TO BE SOME LINGERING STORMS IN THE MORNING
IN THE EAST. AFTER THAT MODELS STILL HAVING TROUBLE WITH THIS DAY ON
THE PRECIPITATION. LIFT REMAINS AROUND ALL DAY AT MID LEVELS WITH
SURFACE SYNOPTIC TROUGH HANGING AROUND SOMEWHERE IN THE AREA WITH
POSSIBLE MESOSCALE BOUNDARIES AND WITH LITTLE TO NO CINH MAKE IT
POSSIBLE FOR THUNDERSTORMS TO BREAK ABOUT ANYWHERE IN THE
AFTERNOON. SO AGAIN BROADBRUSHED SLIGHT CHANCES. EASTERLY WINDS...
AND LINGERING CLOUD COVER AND WITH SLIGHTLY COOLER 850 MB
TEMPERATURES MAKE FOR A LITTLE COOLER DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1129 AM MDT SUN JUL 29 2012
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT BOTH KGLD AND KMCK
THROUGH THE PERIOD. LIGHT SHOWERS ARE IN THE PROCESS OF WEAKENING
AND MOVING EAST OF BOTH TERMINALS...AND SHOULD BE GONE BY VALID
TAF TIME. AS SKIES CLEAR INSTABILITY WILL BEGIN TO INCREASE. WITH
FRONTAL ZONE STILL LINGERING BETWEEN BOTH TERMINALS THUNDERSTORMS
SHOULD BEGIN TO RE-DEVELOP BY MID AFTERNOON AND SHIFT NORTH AND
EAST ACROSS THE AREA. CONFIDENCE IS STILL TOO LOW TO ZERO IN ON AN
EXACT TIME OF OCCURRENCE AT EITHER TERMINAL...SO LEFT VCTS IN
PLACE. THUNDERSTORM ACTIVITY MAY LINGER LONGER AT KMCK THROUGH THE
NIGHT AS A WEAK SHORTWAVE MOVES ACROSS NEBRASKA. WINDS GENERALLY
BE OUT OF THE EAST/SOUTHEAST BELOW 12KT THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BULLER/PMM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
544 AM MDT SUN JUL 29 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MAIN FORECAST PROBLEM WILL BE PRECIPITATION CHANCES THROUGH THE
SHORT TERM. SATELLITE SHOWING THE FLOW HAS DEAMPLIFIED OVER THE LAST
24 HOURS ACROSS MOST OF THE PACIFIC. THIS FLOW THEN TRANSITIONS TO
THE UPPER TROUGH NEAR THE WEST COAST WITH PERSISTENT/BROAD UPPER
RIDGE REMAINING ANCHORED OVER THE CENTER OF THE COUNTRY. CENTER OF
THIS RIDGE HAS MOVED SOUTHEAST FROM YESTERDAY...HOWEVER THE RIDGE HAS
ELONGATED TO THE NORTHWEST.
SATELLITE/UPPER AIR ANALYSIS SHOWS STRONG SUBTROPICAL MOISTURE FEED
AROUND THE WEST AND NORTHERN PORTION OF THE HIGH. BESIDES A SMALL
INCREASE IN MID LEVEL MOISTURE...THE AIR MASS REMAINS NEARLY THE
SAME FROM YESTERDAY. AT MID LEVELS...THE GFS/UKMET WERE DOING A
LITTLE BETTER THAN THE CANADIAN/SREF WITH THE NAM INITIALIZING THE
WORST OF THE BUNCH...ESPECIALLY ON THE CENTER POSITION OF THE RIDGE.
ONGOING CONVECTION AND OUTFLOW BOUNDARIES MAKING A LITTLE HARDER TO
GET A GOOD HANDLE ON THE SURFACE. THE SREF/RUC/HRRR WERE CATCHING
BETTER THAN THE NAM AND ECMWF. MODELS WERE PRETTY CLOSE ON THE LOW
LEVEL THERMAL FIELD. THE NAM/CANADIAN/SREF WERE DOING SLIGHTLY
BETTER.
NAM THROUGH 06Z HAS PRECIPITATION COVERAGE UNDERDONE THAT WAS
OVER/NEAR THE EAST/SOUTHEAST PORTION OF THE AREA. IT PUT MORE
EMPHASIS/PRECIPITATION ON THE WESTERN END OF THE SURFACE THAN IN THE
EAST. TO SOME EXTENT ALL THE MODELS SHOW THAT BIAS. THE SREF AND TO
A LESSER EXTENT THE CANADIAN GOT THAT PRECIPITATION RIGHT. FROM
YESTERDAY...THE RUC AND HRRR STARTED THE PRECIPITATION FURTHER NORTH
AND EAST AND WAS THE MOST CORRECT. THE HRRR TONIGHT IS CATCHING THE
CURRENT PRECIPITATION AREA IN THE EAST WELL.
TODAY/TONIGHT...OVERNIGHT CONVECTION WILL PROBABLY LEAVE AROUND
LEFTOVER BOUNDARIES. MOST MODELS ARE INSISTENT OF STARTING CONVECTION
BY 18Z. SURFACE BOUNDARY NEAR THE SOUTHERN PORTION OF THE AREA WITH
A WEAK SHORTWAVE TROUGH NEAR THE WESTERN PORTION OF THE AREA AT THE
BEGINNING OF THE DAY AS WELL. MODELS HAVE BEEN SIMILAR IN HAVING
THE BEST CHANCE OF PRECIPITATION IN THE WEST AND NORTHERN PORTION OF
THE AREA. SREF AND GEFS PROBABILITIES MATCH UP WHERE THE DEEPEST
LIFT IS. SO ADJUSTED THE CHANCE POPS FURTHER EAST.
MODELS STILL SHOWING IT WARM TODAY. KEPT IT CLOSE TO WHAT THE
WARMEST GUIDANCE WHICH WAS CLOSE TO THE PREVIOUS FORECAST.
MONDAY...THERE LOOKS TO BE SOME LINGERING STORMS IN THE MORNING
IN THE EAST. AFTER THAT MODELS STILL HAVING TROUBLE WITH THIS DAY ON
THE PRECIPITATION. LIFT REMAINS AROUND ALL DAY AT MID LEVELS WITH
SURFACE SYNOPTIC TROUGH HANGING AROUND SOMEWHERE IN THE AREA WITH
POSSIBLE MESOSCALE BOUNDARIES AND WITH LITTLE TO NO CINH MAKE IT
POSSIBLE FOR THUNDERSTORMS TO BREAK ABOUT ANYWHERE IN THE
AFTERNOON. SO AGAIN BROADBRUSHED SLIGHT CHANCES. EASTERLY WINDS...
AND LINGERING CLOUD COVER AND WITH SLIGHTLY COOLER 850 MB
TEMPERATURES MAKE FOR A LITTLE COOLER DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 541 AM MDT SUN JUL 29 2012
AT THIS TIME VFR CONDITIONS ARE EXPECTED AT BOTH TAF SITES. SUBTLE
AND COMPLEX DETAILS AT BOTH SURFACE AND ALOFT MAKE THIS A HARD
FORECAST TO GET A HANDLE ON ANYTHING. COULD BE SOME LIGHT SHOWERS
NEAR KGLD THIS MORNING. BECAUSE OF UNCERTAINTY CHOSE TO HANDLE
THUNDERSTORM FORECAST WITH VCTS. THE BEST CHANCE FOR THUNDERSTORMS
TO AFFECT A TAF SITE AND CAUSE SUB VFR CONDITIONS WILL BE AT KMCK.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BULLER/PMM
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
405 AM MDT SUN JUL 29 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MAIN FORECAST PROBLEM WILL BE PRECIPITATION CHANCES THROUGH THE
SHORT TERM. SATELLITE SHOWING THE FLOW HAS DEAMPLIFIED OVER THE LAST
24 HOURS ACROSS MOST OF THE PACIFIC. THIS FLOW THEN TRANSITIONS TO
THE UPPER TROUGH NEAR THE WEST COAST WITH PERSISTENT/BROAD UPPER
RIDGE REMAINING ANCHORED OVER THE CENTER OF THE COUNTRY. CENTER OF
THIS RIDGE HAS MOVED SOUTHEAST FROM YESTERDAY...HOWEVER THE RIDGE HAS
ELONGATED TO THE NORTHWEST.
SATELLITE/UPPER AIR ANALYSIS SHOWS STRONG SUBTROPICAL MOISTURE FEED
AROUND THE WEST AND NORTHERN PORTION OF THE HIGH. BESIDES A SMALL
INCREASE IN MID LEVEL MOISTURE...THE AIR MASS REMAINS NEARLY THE
SAME FROM YESTERDAY. AT MID LEVELS...THE GFS/UKMET WERE DOING A
LITTLE BETTER THAN THE CANADIAN/SREF WITH THE NAM INITIALIZING THE
WORST OF THE BUNCH...ESPECIALLY ON THE CENTER POSITION OF THE RIDGE.
ONGOING CONVECTION AND OUTFLOW BOUNDARIES MAKING A LITTLE HARDER TO
GET A GOOD HANDLE ON THE SURFACE. THE SREF/RUC/HRRR WERE CATCHING
BETTER THAN THE NAM AND ECMWF. MODELS WERE PRETTY CLOSE ON THE LOW
LEVEL THERMAL FIELD. THE NAM/CANADIAN/SREF WERE DOING SLIGHTLY
BETTER.
NAM THROUGH 06Z HAS PRECIPITATION COVERAGE UNDERDONE THAT WAS
OVER/NEAR THE EAST/SOUTHEAST PORTION OF THE AREA. IT PUT MORE
EMPHASIS/PRECIPITATION ON THE WESTERN END OF THE SURFACE THAN IN THE
EAST. TO SOME EXTENT ALL THE MODELS SHOW THAT BIAS. THE SREF AND TO
A LESSER EXTENT THE CANADIAN GOT THAT PRECIPITATION RIGHT. FROM
YESTERDAY...THE RUC AND HRRR STARTED THE PRECIPITATION FURTHER NORTH
AND EAST AND WAS THE MOST CORRECT. THE HRRR TONIGHT IS CATCHING THE
CURRENT PRECIPITATION AREA IN THE EAST WELL.
TODAY/TONIGHT...OVERNIGHT CONVECTION WILL PROBABLY LEAVE AROUND
LEFTOVER BOUNDARIES. MOST MODELS ARE INSISTENT OF STARTING CONVECTION
BY 18Z. SURFACE BOUNDARY NEAR THE SOUTHERN PORTION OF THE AREA WITH
A WEAK SHORTWAVE TROUGH NEAR THE WESTERN PORTION OF THE AREA AT THE
BEGINNING OF THE DAY AS WELL. MODELS HAVE BEEN SIMILAR IN HAVING
THE BEST CHANCE OF PRECIPITATION IN THE WEST AND NORTHERN PORTION OF
THE AREA. SREF AND GEFS PROBABILITIES MATCH UP WHERE THE DEEPEST
LIFT IS. SO ADJUSTED THE CHANCE POPS FURTHER EAST.
MODELS STILL SHOWING IT WARM TODAY. KEPT IT CLOSE TO WHAT THE
WARMEST GUIDANCE WHICH WAS CLOSE TO THE PREVIOUS FORECAST.
MONDAY...THERE LOOKS TO BE SOME LINGERING STORMS IN THE MORNING
IN THE EAST. AFTER THAT MODELS STILL HAVING TROUBLE WITH THIS DAY ON
THE PRECIPITATION. LIFT REMAINS AROUND ALL DAY AT MID LEVELS WITH
SURFACE SYNOPTIC TROUGH HANGING AROUND SOMEWHERE IN THE AREA WITH
POSSIBLE MESOSCALE BOUNDARIES AND WITH LITTLE TO NO CINH MAKE IT
POSSIBLE FOR THUNDERSTORMS TO BREAK ABOUT ANYWHERE IN THE
AFTERNOON. SO AGAIN BROADBRUSHED SLIGHT CHANCES. EASTERLY WINDS...
AND LINGERING CLOUD COVER AND WITH SLIGHTLY COOLER 850 MB
TEMPERATURES MAKE FOR A LITTLE COOLER DAY.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 405 AM MDT SUN JUL 29 2012
MONDAY NIGHT...AGAIN CANNOT RULE THUNDERSTORMS ANYWHERE DURING THE
DAY AND AGAIN BROADBRUSHED SLIGHT CHANCES EVERYWHERE.
TUESDAY/TUESDAY NIGHT...RIDGE BUILDS IN A LITTLE MORE WITH A WEAK
SHORTWAVE TROUGH COMING IN FROM THE WEST. DO NOT THINK
THUNDERSTORMS WILL GET TOO FAR EAST AND KEPT THEM IN THE WESTERN
HALF OF THE AREA. EAST TO NORTHEAST WINDS WILL ALSO BE IN PLACE.
PRETTY BIG DIFFERENCE MODEL TEMPERATURE OUTPUT FOR THE MAXES. THE
NAM IS MUCH WARMER WITH THE REMAINING MODEL OUTPUT COOLER AND
SIMILAR. NAM HAS BEEN DOING WELL WITH THIS RECENT HEAT. BUT AM
WONDERING IF MAY BE OVERDOING IT A LITTLE. IN GENERAL COMPROMISED
BETWEEN THE WARMER AND COOLER 2 METER TEMPERATURES.
WEDNESDAY THROUGH SATURDAY...A SHORTWAVE TROUGH WILL MOVE ALONG THE
PERIPHERY OF THE RIDGE AND WITH SURFACE TROUGH TO BE POSITIONED
ACROSS THE HIGH PLAINS...WILL LIKELY SEE SOME SCATTERED CONVECTION
DEVELOP AND MOVE ACROSS KANSAS OVERNIGHT. THE REMAINDER OF THE WEEK
WILL SEE PRECIPITATION CHANCES REMAINING TIED TO ANYTHING DEVELOPING
OFF THE HIGHER TERRAIN AND MOVING ACROSS EASTERN COLORADO DURING THE
AFTERNOON HOURS. THE UPPER LEVEL RIDGE WILL GRADUALLY FLATTEN THROUGH
THE WEEK WITH NORTHERN STREAM FLOW BECOMING MORE ZONAL AS A RESULT.
THE CENTER OF THE RIDGE WILL SHIFT EAST BY LATE IN THE WEEK AND INTO
THE WEEKEND AS A SHORTWAVE TROUGH MOVES ACROSS THE SOUTHERN CANADIAN
PLAINS PUSHING A COLD FRONT THROUGH THE CENTRAL PLAINS.
&&
.AVIATION...FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1147 PM MDT SAT JUL 28 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT KMCK AND KGLD.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO MOVE INTO THE AREA
FROM THE WEST DURING THE AFTERNOON AND EVENING. HAVE INTRODUCED A
PROB30 GROUP INTO THE KGLD TAF BETWEEN 22Z-04Z SUNDAY
EVENING...BUT HAVE LEFT KMCK WITHOUT A MENTION OF THUNDERSTORMS
SINCE PROBABILITIES OF THUNDERSTORM DEVELOPMENT ARE LESS FURTHER
EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...BULLER/PMM
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1150 PM MDT SAT JUL 28 2012
.UPDATE...
ISSUED AT 510 PM MDT SAT JUL 28 2012
ISOLATED TO SCATTERED CONVECTIVE ACTIVITY IN THE VICINITY OF A
SURFACE TROUGH SHOULD CONTINUE MOVING TO THE EAST AND DISSIPATE
THROUGH THE EVENING AS THE TROUGH ALSO MOVES FURTHER SOUTH ACROSS
THE FORECAST AREA OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 224 PM MDT SAT JUL 28 2012
WV IMAGERY AND RUC H5 ANALYSIS SHOW STRONG RIDGE EXTENDING FROM THE
WESTERN US TO THE CENTRAL MISSISSIPPI RIVER VALLEY WITH A 597 HEIGHT
CENTER OVER NE OKLAHOMA. A PLUME OF MONSOONAL MOISTURE CONTINUES TO
ADVECT NORTH AND EAST ALONG THE WESTERN EXTENT OF THE RIDGE WITH
SEVERAL WEAK SHORTWAVE TROUGHS MOVING INTO THE TRI-STATE AREA FROM
THE WEST. AT THE SURFACE A COLD FRONT HAS STALLED OVER THE CWA AND
WILL ACT AS THE MAIN FOCUS FOR THUNDERSTORM DEVELOPMENT THROUGH THE
NEXT FEW DAYS.
EARLY THIS AFTERNOON ISOLATED THUNDERSTORMS HAVE ALREADY DEVELOPED
ACROSS THE NE CWA NEAR MCCOOK ALONG THE FRONT WITH CUMULUS FURTHER
SOUTH AND EAST. RUC SOUNDINGS CONTINUE TO SHOW INVERTED-V TYPE
SOUNDINGS ALONG WITH DCAPE VALUES AROUND 1400 J/KG OR GREATER ACROSS
THE EASTERN PART OF THE CWA...WHICH SUPPORTS A THREAT FOR STRONG
DAMAGING WINDS WITH ANY THUNDERSTORMS THAT DEVELOP. PWAT VALUES ARE
ACTUALLY PRETTY GOOD WITH VALUES AROUND 1.4-1.5 AS A RESULT OF
MONSOONAL MOISTURE ADVECTING INTO THE MID LEVELS...SO THUNDERSTORM
COULD BE GOOD RAIN PRODUCERS THOUGH STORM MOTIONS AROUND 20KT SHOULD
KEEP FLASH FLOOD THREAT LIMITED. STORM THUNDERSTORM ACTIVITY THIS
EVENING SHOULD BE TIED TO DIURNAL PROCESSES WITH ACTIVITY ENDING
SHORTLY AFTER SUNRISE.
SUNDAY...THERE WILL BE VERY LITTLE CHANGE IN THE PATTERN AS THE
STATIONARY FRONT LINGERS OVER THE CWA...AND THE RIDGE REMAINS IN
PLACE. THUNDERSTORMS SHOULD REDEVELOP BY THE AFTERNOON WITH THE
FRONT AGAIN ACTING AS THE MAIN FOCUS FOR INITIATION. NAM SOUNDINGS
SHOW EVEN BETTER MID LEVEL MOISTURE SUNDAY AFTERNOON WITH PWAT
VALUES IN EXCESS OF 1.6...WHICH IS ANOMALOUSLY HIGH FOR THIS TIME
OF YEAR. CONSIDERING THAT AND VERY LIGHT STORM MOTIONS ON SUNDAY
IN THE ABSENCE OF ANY FLOW ALONG THE STATIONARY FRONT...THERE WILL
BE AN INCREASED THREAT OF FLASH FLOODING WITH ANY THUNDERSTORMS
THAT DO DEVELOP. COVERAGE WILL BE A QUESTION...SO I AM NOT
CONFIDENT ENOUGH TO ISSUE A FLASH FLOOD WATCH FOR SUNDAY
AFTERNOON/EVENING DURING THIS FORECAST CYCLE...HOWEVER THIS SHOULD
BE WATCHED GOING FORWARD.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 112 PM MDT SAT JUL 28 2012
UPPER RIDGE OVER THE SOUTHERN PLAINS WILL DRIFT WEST SOUTHWESTWARD
DURING THIS PERIOD. FAST MOVING SHORTWAVE TROUGHS RIDING THE RIDGE
MIGHT BE CLOSE ENOUGH TO PROVIDE WEAK LIFT FOR ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS...BUT CONFIDENCE IS LOW AND DO NOT
WARRANT MORE THAN A SLIGHT TO LOW CHANCE MENTION. TEMPERATURES
WILL CONTINUE TO BE ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1147 PM MDT SAT JUL 28 2012
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD AT KMCK AND KGLD.
ISOLATED TO SCATTERED THUNDERSTORMS EXPECTED TO MOVE INTO THE AREA
FROM THE WEST DURING THE AFTERNOON AND EVENING. HAVE INTRODUCED A
PROB30 GROUP INTO THE KGLD TAF BETWEEN 22Z-04Z SUNDAY
EVENING...BUT HAVE LEFT KMCK WITHOUT A MENTION OF THUNDERSTORMS
SINCE PROBABILITIES OF THUNDERSTORM DEVELOPMENT ARE LESS FURTHER EAST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...024
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS JACKSON KY
1015 PM EDT MON JUL 30 2012
.UPDATE...
ISSUED AT 1015 PM EDT MON JUL 30 2012
CONVECTION ASSOCIATED WITH OUTFLOW BOUNDARIES OVER OUR EASTERN MOST
COUNTIES HAS DIED OUT WITH SUNSET. BUT STORMS CONTINUE TO DEVELOP
FURTHER TO THE EAST. SO COULD NOT RULE OUT A RENEGADE SHOWER OR
THUNDERSTORM SHOULD ANOTHER OUTFLOW SHOOT WESTWARD. FOR NOW WENT
OPTIMISTIC AND LEFT ANY MENTION OF POPS OUT OF THE FAR EAST AS
CONVECTION HAS A VERY SLOW BUT DEFINITE NORTHEAST TREND IN ITS
MOVEMENT.
SHORT WAVE ENERGY IS CURRENTLY DROPPING INTO THE LOWER AND MID OHIO
VALLEY REGION. THE RUC APPEARS TO HAVE A VERY GOOD HANDLE ON THE
SITUATION WITH CONVECTION FIRING IN SOUTHERN IL/IN ATTM. EXPECT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OVER OUR
SOUTHWESTERN ZONES AFTER MIDNIGHT AND GENERALLY SOUTH OF A MOUNT
VERNON TO WHITESBURG LINE.
UPDATED THE FORECAST PACKAGE FOR SOME MINOR TWEAKS...MAINLY TO TEMPS
AND DEW POINTS AS TEMPERATURES HAVE DROPPED A LITTLE FASTER THAN
ANTICIPATED IN SEVERAL OF OUR VALLEY AREAS. ALSO FRESHENED UP WORDING
IN THE ZONE PACKAGE.
UPDATE ISSUED AT 721 PM EDT MON JUL 30 2012
OUTFLOW BOUNDARIES GENERATED FROM THUNDERSTORMS OVER WV HAVE BECOME
THE FOCUS FOR SOME ISOLD SHOWER ACTIVITY ACROSS PIKE AND LETCHER
COUNTIES. UPDATED THE FORECAST PACKAGE FOR THIS ACTIVITY THOUGH EXPECT
THINGS TO DIE DOWN QUICKLY AFTER SUNSET. REST OF THE FORECAST IS ON
TRACK. ONLY MINOR TWEAKS TO SKY AND POPS. OTHERWISE BROUGHT HOURLY
GRIDS IN LINE WITH MOST RECENT OBS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 330 PM EDT MON JUL 30 2012
AN UPPER LEVEL RIDGE REMAINS CENTERED NEAR THE TX PANHANDLE REGION
WITH A TROUGH BETWEEN THIS RIDGE AND ANOTHER OVER THE ATLANTIC. AS A
RESULT THE REGION CONTINUES IN NW FLOW ALOFT. AT THE SFC...HIGH
PRESSURE HAVE MOVED ON OFF TO OUR N AND E WITH A SFC LOW CENTERED
OVER SE MS AND A WARM FRONT EXTENDING SE FROM THE LOW INTO THE TN
VALLEY REGION. CONVECTION HAS BEEN PRESENT NEAR THIS BOUNDARY TODAY
AS WELL AS OVER SOME OF THE HIGHER TERRAIN OF THE CENTRAL AND
SOUTHERN APPALACHIANS. THERE MAY HAVE BEEN A FEW SPRINKLES IN FAR
SOUTHERN PIKE COUNTY NEAR THE VA LINE OVER THE PAST HOUR. OTHER THAN
A BIT DEEPER CU IN THAT VICINITY...JUST FAIR WEATHER CU HAS BEEN THE
DOMINANT FEATURE WITH TEMPS THUS FAR NEAR WHAT WOULD BE EXPECTED IN
LATE JULY.
A COUPLE OF UPPER LEVEL DISTURBANCES IN THE NW FLOW ALOFT MAY IMPACT
THE REGION DURING THE PERIOD. THE FIRST MOVING FROM THE MO VALLEY
TOWARD THE MID MS VALLEY REGION IS GENERALLY PROGGED TO TRACK TO THE
SW OF THE REGION AND INTERACT WITH THE BOUNDARY SW OF THE REGION. AT
THE SFC...THE RELATIVELY WEAK SFC LOW MAY TRACK TOWARD THE MIDDLE TN
REGION BY DAWN ON TUE...AND GENERALLY BECOMING DIFFUSE...WHILE A COLD
FRONT ASSOCIATED WITH A SHORTWAVE TO MOVE TROUGH THE GREAT LAKES
REGION LATE TONIGHT INTO TUE NIGHT APPROACHING THE REGION ON TUE.
THIS BOUNDARY SHOULD CROSS THE REGION ON TUE EVENING. SINCE THE FIRST
SHORTWAVE IS EXPECTED TO TRACK TO OUR SW AND THE SECOND TO OUR
NORTH...THE BEST DYNAMICS AND FORCING WILL NOT BE DIRECTLY OVER THE
REGION WITH EITHER ONE. WITH THIS IN MIND...POPS OF NO MORE THAN
CHANCE WERE USED. THE NE TWO THIRDS OF THE REGION SHOULD BE FAR
ENOUGH NORTHEAST TO REMAIN DRY TONIGHT WITH CONVECTION CHANCES BETTER
OVER THE CUMBERLAND VALLEY REGION. CONVECTION ON TUE SHOULD BE
DIURNALLY INFLUENCED...WITH THE THREAT LINGERING INTO THE EVENING AS
THE BOUNDARY SHOULD NOT CROSS THE AREA UNTIL THE OVERNIGHT. OVER THE
NE CWA TONIGHT...PATCHY VALLEY FOG IS AGAIN EXPECTED.
AS FOR TEMPS...THERE SHOULD BE A WINDOW ON TUE DURING THE MORNING
THROUGH EARLY AFTERNOON WHERE CLOUDS SHOULD THIN. MODEL GUIDANCE
POINTED TOWARD A BIT HIGHER MAX T ON TUE THAN THE PREVIOUS FORECAST...
NEAR 90 CWAWIDE. MIN T THROUGH THE PERIOD WILL BE NEAR TO SLIGHTLY
ABOVE NORMAL...ESPECIALLY ON TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 PM EDT MON JUL 30 2012
MODELS CONTINUE TO AGREE WITH OVERALL PATTERN EVOLUTION THROUGH THE
UPCOMING WEEK. TROF IN THE EASTERN UNITED STATES AND MEAN RIDGE IN
THE PLAINS WILL FLATTEN WITH FLOW BECOMING MORE ZONAL ACROSS THE
NORTHERN U.S. A SIGNIFICANT SHORT WAVE TROF IS PROGGED TO MOVE EAST
IN THE FAST FLOW ACROSS THE FAR NORTHERN PART OF THE COUNTRY DURING
THE LATTER PART OF THE WEEK AND DURING THE UPCOMING WEEKEND.
MODELS HAVE BEEN TRENDING DRIER FOR THE BEGINNING PART OF THE LONG
TERM FORECAST. WILL CARRY ONLY HAVE A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EXTREME EAST ON WEDNESDAY...BASICALLY PIKE
COUNTY ONLY...WITH A DRY FORECAST ELSEWHERE. WILL THEN GO WITH A DRY
FORECAST FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. AS DEEPER
MOISTURE RETURNS IN LOW LEVEL SOUTHWESTERLY FLOW AND WAA PATTERN
SETS UP IN ADVANCE OF LOW PRESSURE IN PLAINS WILL SEE A CHANCE OF
THUNDERSTORMS RETURN IN THE WEST PART OF FORECAST AREA ON FRIDAY
WITH A SLIGHT CHANCE IN THE EAST. AS LOW PRESSURE MOVES EAST ACROSS
SOUTHERN CANADA THIS WEEKEND A COLD FRONT WILL APPROACH THE AREA. IT
APPEARS THE FRONT WILL NOT MOVE SOUTH OF KY UNTIL MONDAY...THUS
KEEPING SHOWER AND THUNDERSTORM CHANCES IN THE FORECAST THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK. THE EXTENDED INITIALIZATION
PROCEDURE HANDLED THIS WELL WITH RAIN CHANCES CONTINUING INTO
MONDAY.
MAXIMUM TEMPERATURES SHOULD CONTINUE TO AVERAGE NEAR TO SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD...WITH WARMER THAN NORMAL MINIMUM
TEMPERATURES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 721 PM EDT MON JUL 30 2012
A SHORTWAVE WILL INTERACT WITH A WARM FRONT TO OUR SW AND COULD
PRODUCE SOME SHOWER AND THUNDERSTORM ACTIVITY ACROSS SOUTHERN
KY...GENERALLY S AND SW OF LOZ AND SME. VFR CIGS ARE DEFINITE
POSSIBILITY ACROSS OUR SOUTH...SOUTHWEST AS WE PROGRESS THROUGH THE
NIGHT. CLOUD COVER TO THE NE AND IN PARTICULAR JKL...AND PORTIONS OF
THE KY...LICKING RIVER BASINS SHOULD BE THINNER AND LEAD TO RIVER
VALLEY FOG BETWEEN 6Z AND ROUGHLY 14Z POSSIBLY AFFECTING K22...PBX...
CPF...AND I35.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RAY
SHORT TERM...JP
LONG TERM....SBH
AVIATION...PELTON/RAY
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1133 AM CDT SUN JUL 29 2012
.DISCUSSION...
THIN CIRRUS OVERHEAD WITH TEMPERATURES RIGHT ON TRACK. NO CHANGES
TO HIGHS...BUT SLIGHT TWEAKS TO DEW POINTS DURING THE MID TO LATE
AFTERNOON. WE WILL CONTINUE THE HEAT ADVISORY AS WE WILL BUCK
WARNING CRITERIA WHERE RAIN DID FALL YESTERDAY. HARD TO SAY WHERE
A CU FIELD MAY CROP UP BUT OUR SOUNDING AND UPSTREAM LITTLE ROCKS
IS PRETTY DRY IN THE LOW LEVELS WHILE LAKE CHARLES AND JACKSON ARE
180 OUT. SO THINKING FROM MONROE TO LUFKIN AND SOUTH FOR LOW LEVEL
CONVERGENCE OF ANY SORT. HAVE INCREASED POPS...BUT STILL ONLY A
SILENT CHANCE FOR ISOLATED ACTIVITY WHICH A NOWCAST WILL MORE THAN
HANDLE. ALTHOUGH RAP DOES SHOW QPF OVER DEEP EAST TEXAS THIS
MORNING...JUST LEFT OVER POOLED MOISTURE FROM YESTERDAY AND THEN
NOTHING IN THE HEAT OF MIDAFTERNOON...BUT MORE QPF THERE LATE IN
THE DAY. REALITY CHECK SHOWS ECHOES OFF SHORE FOR THE MOST PART
AT THIS TIME. AN OUTFLOW BOUNDARY HAS JUST CROPPED UP ON KLCH 88D
AND IS MOVING NE AND COULD TURN AROUND SOME LOW LEVEL STUFF...BUT
ANYTHING THUNDERING WOULD SLIDE RIGHT BACK WESTWARD BASED ON THEIR
SOUNDING. HPC LATEST SHOWS NO QPF AND SPC/S GENERAL LINE IS RIDING
OUR SOUTHERN TIER. SO WILL MONITOR FOR ANYTHING SPECIAL...BUT THE
UPPER RIDGE IS STRONGEST OVER OUR NW QUAD OF COUNTIES WITH LITTLE
IF ANY CHANCE FOR I-30 CORRIDOR AND MAY EVEN BE LEANING OVER I-20
A GOOD BIT. /24/
&&
.AVIATION...
VFR FLIGHT CONDITIONS WILL BE COMMON ACROSS THE ARKLATEX THIS
PERIOD...AS HIGH PRESSURE ALOFT CONTINUES TO INFLUENCE A DRY WEATHER
PATTERN. WX WILL CONTINUE TO BE ABSENT FROM THE 18Z TAF
PACKAGE...BUT ISOLATED TSRA ACTIVITY CAN NOT BE TOTALLY RULED OUT
THIS AFTERNOON. ANY TSRA ACTIVITY NEAR TERMINALS WILL BE HANDLED
WITH AN AMD. LIGHT AND VARIABLE WINDS WILL CONTINUE...WITH NO VSBY
CONCERNS EXPECTED IN THE 18Z PACKAGE. /11/
&&
.PREV DISCUSSION... /ISSUED 256 AM CDT SUN JUL 29 2012/
DISCUSSION...
UPPER LEVEL RIDGE CENTERED OVER NORTH TEXAS AND SOUTHERN OKLAHOMA WILL
REMAIN IN PLACE THROUGH MONDAY. THIS WILL BRING BASICALLY NO RAIN
AND AND VERY HOT TEMPERATURES TO THE FOUR STATE REGION. COMBINED
WITH THE HIGH DEWPOINTS...THE HEAT INDEX VALUES WILL TOP 105 OVER
MOST OF THE AREA TODAY AND MONDAY. CANNOT RULE DEVELOPMENT OF
CONVECTION DURING THE HOTTEST PART OF DAY...BUT IF ANY...IT WILL
BE VERY LOCALIZED. THE CENTER OF THE RIDGE WILL SHIFT WEST
TUESDAY INTO WEST TEXAS AND WEAKEN SLIGHTLY. THIS MAY ALLOW
TEMPERATURES TO EASE A BIT. BY THURSDAY...AN INCREASE IN MOISTURE
ON THE EAST SIDE OF THE RIDGE...COMBINED WITH WEAK UPPER LEVEL
DISTURBANCES...MAY RESULT IN FEW SHOWERS AND THUNDERSTORMS...MAINLY
EASTERN AREAS. THIS PATTERN...WITH ISOLATED AFTERNOON CONVECTION WILL
CONTINUE INTO NEXT WEEKEND.
A HEAT ADVISORY HAS BEEN ISSUED FOR TODAY AND MONDAY TO COVER THE
EXCESSIVE HEAT.
AVIATION...
STRONG UPPER LEVEL RIDGE OVER THE REGION AND DRY CONDITIONS WILL
ALLOW VFR CONDITIONS TO PREVAIL THROUGH THE TAF PERIOD. SOME CONCERN
THAT A WEAK UPPER LEVEL DISTURBANCE MOVING SOUTH THROUGH MISSOURI
MAY PROVIDE JUST ENOUGH SUPPORT FOR ISOLATED CONVECTION THIS
AFTERNOON...MAINLY ACROSS N LA/SRN AR. HOWEVER...CONFIDENCE IS
LOW SO WILL LIKELY NOT INCLUDE ANY TSTM REMARKS WITH THE 12Z TAF
ISSUANCE. OTHERWISE...WLY SFC WINDS ARE EXPECTED ACROSS E TX VEERING
TO NELY OVER NW LA/SRN AR. SPEEDS WILL BE BETWEEN 5-10 KTS DURING
THE DAYTIME BEFORE BECOMING LIGHT AND VARIABLE AFTER SUNSET SUNDAY.
/09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 103 77 101 77 102 / 10 10 10 10 0
MLU 101 75 100 75 99 / 10 10 10 10 10
DEQ 102 72 104 74 102 / 10 10 10 10 0
TXK 101 76 104 76 101 / 10 10 10 10 0
ELD 101 74 103 74 102 / 10 10 10 10 10
TYR 102 76 103 77 100 / 10 10 0 0 0
GGG 102 74 102 76 100 / 10 10 10 10 0
LFK 99 76 99 76 98 / 10 10 10 10 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
ARZ050-051-059>061-070>073.
LA...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
LAZ001>006-010>014-017>022.
OK...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
OKZ077.
TX...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR THE FOLLOWING ZONES:
TXZ096-097-108>112-124>126-136>138-149>153-165>167.
&&
$$
24/11
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
953 PM EDT MON JUL 30 2012
.SYNOPSIS...
ISSUED AT 345 PM EDT MON JUL 30 2012
A COLD FRONT WILL SWEEP SOUTHEAST THROUGH MICHIGAN TONIGHT...
BRINGING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. SOME OF
THE STORMS MAY BE STRONG TO SEVERE WEST OF HIGHWAY 131.
RAIN WILL END TUESDAY MORNING AS THE FRONT DEPARTS... WITH
DECREASING CLOUDS FOLLOWING. STRONG NORTH WINDS BEHIND THE FRONT
WILL CREATE HAZARDOUS SWIMMING AND BOATING CONDITIONS ON LAKE
MICHIGAN FOR TUESDAY AFTERNOON AND EVENING.
HIGH PRESSURE WILL PROVIDE DRY AND PLEASANT WEATHER ON WEDNESDAY...
THEN ANOTHER COLD FRONT WILL BRING A THREAT OF SHOWERS AND
THUNDERSTORMS ON THURSDAY.
&&
.UPDATE...
ISSUED AT 953 PM EDT MON JUL 30 2012
RADAR IS CURRENTLY LIT UP FROM THE BRIDGE SOUTHWEST TO NEAR
MANITOWOC. NEW ECHOS WERE FORMING SW OF MANITOWOC ACROSS CENTRAL
WISCONSIN AHEAD OF A COLD FRONT. LATEST HRRR BRINGS A BROKEN LINE
OF STORMS ACROSS THE CWA LATE TONIGHT. SHEAR VALUES ARE
CONSIDERABLY LESS ACROSS LOWER MI THAN ACROSS WISCONSIN. THINKING
THAT CHCS OF SVR STORMS ARE DIMINISHING BASED ON TIME OF DAY AND
MODEL PROGS OF SHEAR BUT A STRONG STORM OR TWO IS CERTAINLY
POSSIBLE. TWEAKED POPS TO REFLECT A BIT SLOWER TIMING THROUGH THE
CWA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON JUL 30 2012
THE MID LEVEL SHORTWAVE TROUGH NOW OVER THE LAKE SUPERIOR REGION
WILL DIG SEWD TONIGHT. HEIGHT FALLS ASSOCIATED WITH THIS AMPLIFYING
WAVE AND LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SFC COLD FRONT
WILL SET OFF A SCT-BKN LINE OF CONVECTION TO OUR NW OVER WI LATE
THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO EASILY SURVIVE THE TREK
ACROSS LAKE MI THIS EVENING AS AXIS OF INSTABILITY WITH MUCAPES
AROUND 2000 J/KG LEANS INTO WRN LWR MI AHEAD OF THE FRONT. LAKE MI
ACTUALLY MAY ALSO PROVIDE SOME BOOST GIVEN THE VERY WARM WATER TEMPS
AND ADDED SOURCE OF MOISTURE. HAVE RAISED POPS TO LIKELY OVER MUCH
OF THE CWFA TONIGHT.
SOME WIND DAMAGE MAY OCCUR WITH ANY ORGANIZED/BOWING LINES OF
CONVECTION TONIGHT. ALL THE JUICY DETAILS RELATED TO SEVERE WX
POTENTIAL CAN BE FOUND IN THE SPC DAY1 OTLK AS WELL AS ANY MESOSCALE
DISCUSSIONS FOR OUR AREA.
BELIEVE MOST OF THE CONVECTION WILL EXIT TO THE SOUTHEAST ON TUESDAY
MORNING. HOWEVER IT IS POSSIBLE SOME ENHANCEMENT AND/OR NEW
DEVELOPMENT WILL TAKE PLACE NEAR JXN IN THE LATE MORNING PRIOR TO
THE FRONT FULLY EXITING TO THE SE.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON JUL 30 2012
THE FOCUS OF THE LONG TERM WILL BE ON TWO SYSTEMS THAT WILL BE
MOVING THROUGH THE AREA. NO MAJOR CHANGES ARE NEEDED TO THE FCST AS
THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH DECENT RUN TO RUN
CONTINUITY.
UPPER NW FLOW EXPECTED TO BE ALOFT MOST OF THIS WEEK WILL HOLD ON
FOR ONE MORE DAY ON THU/THU NIGHT AS A SOMEWHAT DISORGANIZED SHORT
WAVE MOVES THROUGH JUST NORTH OF THE AREA. THIS WAVE WILL HELP TO
PUSH A COLD FRONT SOUTH THROUGH THE AREA. MOST OF THE DYNAMICS WILL
REMAIN JUST NORTH OF THE AREA WITH THIS WAVE. THE FRONT WILL BE
WEAKENING AS IT PUSHES SOUTH THROUGH THE AREA. H850 TEMPS AROUND 20C
WILL HELP TEMPS WARM TO AROUND 90 THU AFTERNOON.
THE NW UPPER FLOW IS EXPECTED TO BEGIN FLATTENING OUT SOME THEN ON
FRI. THIS OCCURS AS THE STRONG WAVE THAT COMES FROM ITS CURRENT
POSITION ACROSS THE NRN PACIFIC TRANSLATES INTO THE AREA FOR NEXT
WEEKEND. MODELS ARE STARTING TO INDICATE THAT A WAVE MAY RIDE ALONG
THE STALLING OUT FRONT TO OUR SOUTH ON FRI. IF IT STALLS OUT A
LITTLE FURTHER NORTH...FRI MAY END UP A BIT MORE WET THAN CURRENTLY
INDICATED.
MODELS HAVE BEEN INDICATING THAT SAT AND SAT NIGHT COULD BE A
SOMEWHAT WET PERIOD AND POTENTIALLY ACTIVE AS THE STRONG WAVE/LOW
WILL BEGIN MOVING INTO THE AREA. STRONG FORCING AHEAD OF IT...ALONG
WITH A MOISTURE FEED FROM THE GULF WILL HELP TO BRING A GOOD CHC OF
PCPN TO THE AREA. THE NEW 12Z EURO JUST COMING IN IS NOW SLOWING THE
SYSTEM UP A BIT...SO WE WILL NEED TO WATCH THAT TREND.
WE SHOULD CLEAR OUT RATHER WELL AND COOL OFF A BIT BEHIND THE
SAT/SAT NIGHT SYSTEM AS A NICE CANADIAN AIR MASS ADVECTS IN. THIS
WILL DOMINATE THE WEATHER FOR THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 804 PM EDT MON JUL 30 2012
LINE OF STRONG TO SEVERE STORMS EXTENDS FROM THE EASTERN UPPER
PENINSULA SOUTHEAST TO NEAR GREEN BAY. THE MAIN POINT OF CONTENTION
WITH THIS SET OF TAFS IS WHAT THIS LINE DOES AT IT WORKS ITS WAY
SOUTH AND EAST OVER THE COURSE OF THE NEXT 12 HOURS.
HAVE BROUGHT PREVAILING THUNDERSTORMS INTO THE WESTERN TAF SITES
OF KMKG...KGRR AND KAZO BETWEEN 03Z AND 08Z. INLAND TAF SITES ARE
A BIT TRICKIER AND DECIDED TO JUST USE VCTS WORDING AT THIS POINT.
HAVE KEPT CEILINGS VFR THROUGH THE PERIOD...WITH MVFR VSBY/S IN
THE WESTERN SITES AS STORMS MOVE THROUGH.
SHOWERS AND STORMS SHOULD MOVE SOUTH AND EAST OF THE TAF SITES
THROUGH THE COURSE OF TUESDAY MORNING BETWEEN 12Z AND 16Z.
&&
.MARINE...
ISSUED AT 345 PM EDT MON JUL 30 2012
WILL ISSUE A SMALL CRAFT ADVISORY FOR TUESDAY AFTERNOON AND EVENING.
INCREASING NORTH FLOW AND COLD ADVECTION OVER VERY WARM LAKE WATERS
IS BOUND TO KICK UP THE LAKE TO ADVISORY LEVELS.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT MON JUL 30 2012
RAIN AMOUNTS WITH THE FRONT TONIGHT SHOULD BE GENERALLY ONE QUARTER
TO ONE HALF INCH. HOWEVER SOME LOCALLY HIGHER AMOUNTS NEAR ONE INCH
ARE CERTAINLY POSSIBLE. WHILE LOCALIZED NUISANCE FLOODING IS
POSSIBLE IN URBAN AREAS IF/WHERE HEAVY DOWNPOURS OCCUR... WE REALLY
NEED THIS RAIN FOR DROUGHT RELIEF.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM TUESDAY AFTERNOON THROUGH LATE
TUESDAY NIGHT FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY FROM NOON TUESDAY TO 5 AM EDT WEDNESDAY FOR
LMZ844>849.
&&
$$
UPDATE...93
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...DUKE
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 PM EDT SUN JUL 29 2012
.UPDATE...
ISSUED AT 1248 PM EDT SUN JUL 29 2012
WILL NEED TO KEEP AN EYE ON THE NEAR TERM...WITH THE LINE OF WARNED
TSRA THAT DEVELOPED DURING THE MORNING HOURS NORTH OF MN IN ONTARIO.
WHILE MUCH OF THE STRONGER ACTIVITY WILL LIKELY REMAIN IN CANADIAN
WATERS...THE NEARLY 35KT SE TRACK ACROSS ISLE ROYALE BY 20Z...AND
THE KEWEENAW PENINSULA BY 22Z IF TSRA REMAIN AT THE CURRENT SPEED.
WILL CONTINUE TO MONITOR AND INCREASE CLOUD COVER AS IT BLOWS OFF
OUT AHEAD OF THE STORMS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 125 PM EDT SUN JUL 29 2012
HIGH PRESSURE IS EXITING TO OUR SE...WITH A RIDGE REMAINING OVERHEAD
THROUGH THE EVENING HOURS. AN UPPER LEVEL DISTURBANCE IN CHARGE OF
HELPING TO CREATE TSRA ACTIVITY OVER W ONTARIO/N MN THIS AFTERNOON
HAS THE BEST CHANE OF INFLUENCING CMX BY LATE AFTERNOON WITH MOSTLY
MORE CLOUDS. POP UP CONVECTION COULD ALSO GET TO SAW BEFORE SUNSET
AS WELL...BUT WITH THE LOW PROBABILITY AND LIMITED IMPACT...IT HAS
BEEN KEPT OUT OF THE FCST FOR NOW.
NEARING LOW PRESSURE STRETCHING FROM W ND THROUGH
MANITOBA WILL BECOME BETTER ORGANIZED AS IT BECOMES DRAPED FROM THE
ARROWHEAD OF MN TO JAMES BAY BY 12Z MONDAY. THE MAIN RESULT AT THE
TAF SITES WILL BE INCREASED CLOUD COVER...AND A SMALL CHANCE OF RAIN
SHOWERS /VCSH ADDED DUE TO UNCERTAINTY/ AS THE LOW SLIDES ACROSS W
LAKE SUPERIOR BY EARLY AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KF
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1248 PM EDT SUN JUL 29 2012
.UPDATE...
ISSUED AT 1248 PM EDT SUN JUL 29 2012
WILL NEED TO KEEP AN EYE ON THE NEAR TERM...WITH THE LINE OF WARNED
TSRA THAT DEVELOPED DURING THE MORNING HOURS NORTH OF MN IN ONTARIO.
WHILE MUCH OF THE STRONGER ACTIVITY WILL LIKELY REMAIN IN CANADIAN
WATERS...THE NEARLY 35KT SE TRACK ACROSS ISLE ROYALE BY 20Z...AND
THE KEWEENAW PENINSULA BY 22Z IF TSRA REMAIN AT THE CURRENT SPEED.
WILL CONTINUE TO MONITOR AND INCREASE CLOUD COVER AS IT BLOWS OFF
OUT AHEAD OF THE STORMS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 724 AM EDT SUN JUL 29 2012
EXPECT VFR CONDITIONS/LGT WINDS TODAY WITH HI PRES DOMINATING. THE
APRCH OF A DISTURBANCE LATER TNGT MAY BRING SOME SOME SHRA/TS TO
MAINLY CMX...BUT CONCERNS ABOUT SUFFICIENT MSTR RETURN/TIMING AND
COVERAGE DO NOT ALLOW FOR A FCST OF MORE THAN VCSH ATTM. VFR
CONDITIONS SHOULD BE THE RULE TNGT AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KF
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
724 AM EDT SUN JUL 29 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 724 AM EDT SUN JUL 29 2012
EXPECT VFR CONDITIONS/LGT WINDS TODAY WITH HI PRES DOMINATING. THE
APRCH OF A DISTURBANCE LATER TNGT MAY BRING SOME SOME SHRA/TS TO
MAINLY CMX...BUT CONCERNS ABOUT SUFFICIENT MSTR RETURN/TIMING AND
COVERAGE DO NOT ALLOW FOR A FCST OF MORE THAN VCSH ATTM. VFR
CONDITIONS SHOULD BE THE RULE TNGT AS WELL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
419 AM EDT SUN JUL 29 2012
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 417 AM EDT SUN JUL 29 2012
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER THE PLAINS AND TROFFING OVER ERN
NAMERICA. SFC HI PRES CENTERED OVER LOWER MI/DRY AIRMASS DEPICTED ON
THE 00Z GRB RAOB IS BRINGING A TRANQUIL EARLY MRNG TO THE CWA. A
SHRTWV OVER SW MN PER RUC ANALYSIS TOPPING THE PLAINS RDG AND MOVING
ESEWD IS BRINGING AN AREA OF MAINLY MID/HI CLD INTO NRN MN. THICKER
CLDS/SOME SHRA AND A FEW TS ARE APPARENT S OF A LINEEXTENDING W OF
DLH CLOSER TO THE SHRTWV AND MORE MOIST AIRMASS SHOWN ON THE 00Z
ABERDEEN SDAKOTA RAOB. THESE SHRA ARE MOVING ESEWD AND APPEAR TO BE
ON A TRACK TO MISS UPR MI. ANOTHER STRONGER SHRTWV TOPPING THE
PLAINS RDG IS MOVING W-E INTO SRN SASKATCHEWAN.
TODAY...SHRTWV MOVING THRU SW MN AND ACCOMPANYING DPVA/DEEP LYR
QVECTOR CVNGC ARE PROGGED TO SHIFT ESEWD AND FOR THE MOST PART MISS
UPR MI. HOWEVER...SEVERAL MODELS...INCLUDING THE QUITE PERSISTENT
GFS AS WELL AS THE 00Z NAM/REGIONAL CNDN MODELS GENERATE SOME PCPN
OVER PORTIONS OF THE CWA AS THE SW FLOW ADVECTS MORE HUMID LLVL AIR
OVER UPR MI IN THE PRESENCE OF DAYTIME HEATING. THE NAM GENERATES
THE SHRA OVER THE NRN TIER COUNTIES THIS AFTN WHERE SOME LK BREEZE
CONVERGENCE MIGHT BE PSBL AS THE LK BREEZE BNDRY TRIES TO PUSH
INLAND INTO THE FAIRLY LGT SW SYNOPTIC SCALE FLOW. THE CNDN MODEL
ALSO INDICATES THIS AS WELL...BUT ALSO BRUSHES THE WI BORDER
COUNTIES WITH SOME -SHRA THIS MRNG ON THE NRN FRINGE OF SHRA APPEAR
IMPACTING MAINLY WI. ON THE OTHER HAND...THE LOCAL WRF-ARW AND A HI
RES MODEL WITH EXPLICIT CONVECTION BOTH GENERATE NO PCPN.
CONSIDERING THE TRENDS FOR THE SHRA IN MN TO BE SLIDING ESEWD AS
WELL AS THE LARGER SCALE ACYC FLOW AND WARMTH OF THE MID LVLS SHOWN
ON THE 00Z INL RAOB THAT SUPPORTS THE MORE STABLE FCST SDNGS SHOWN
BY THE LOCAL WRF-ARW...OPTED TO RETAIN GOING DRY FCST. SO INCRSG
LLVL DEWPTS WL BE MANIFEST AS SCT-BKN CU THIS AFTN. MIXING TO H75-8
ON THESE SDNGS YIELDS HI TEMPS TOPPING OUT IN THE 80-85 RANGE AWAY
FM LK MODERATION...WHICH SHOULD BE MOST PRONOUNCED DOWNWIND OF LK MI.
TNGT...THIS EVENING SHOULD REMAIN DRY OVER UPR MI WITH HI PRES/
LINGERING DRY/STABLE AIR DOMINATING. LATER AT NGT...DISTURBANCE NOW
IN SASKATCHEWAN IS FCST TO SLIDE ESEWD TO JUST N OF INL BY 12Z MON.
VIGOROUS DPVA/DEEP LYR QVECTOR CNVGC IN ADVANCE OF THIS FEATURE IS
PROGGED TO IMPACT THE WRN ZNS AFT 06Z AND INTERACT WITH FAIRLY STEEP
MID LVL LAPSE RATES. DESPITE THE FAIRLY STRONG DYNAMICS...QUESTIONS
ABOUT MSTR RETURN THAT WOULD BE NECESSARY TO DRIVE NOCTURNAL SHRA/
TS...THE NAM ACTUALLY SHOWS NEGATIVE H85 THETA E ADVCN IN THE
06Z-12Z TIME FRAME...LIMITS FCST POPS TO NO HIER THAN HI CHC FOR
NOW. ALSO...SLOWED PREVIOUS FCST POPS BY ABOUT 3 HRS TO ACCOUNT FOR
SOMEWHAT SLOWER ARRIVAL OF SHARPER DPVA/QVECTOR CNVGC. AS FOR
TEMPS...MINS WL BE WARMEST OVER THE W WITH SOMEWHAT STRONGER LLVL
WINDS ARRIVING LATE IN ADVANCE OF APRCHG SHRTWV.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 417 AM EDT SUN JUL 29 2012
MUCH OF THE LONG TERM PERIOD WILL BE MARKED BY THE PERSISTENT UPPER
RIDGE SITTING JUST EAST OF THE ROCKIES AND AN UPPER TROUGH OVER ERN
CANADA AND THE ERN GREAT LKS. THIS WILL PUT THE UPPER GREAT LAKES
REGION UNDER NW FLOW ALOFT AND LEAD TO A SERIES OF SHORTWAVES
SLIDING ACROSS THE AREA...PROVIDING THE POTENTIAL FOR SHOWERS AND
THUNDERSTORMS.
THE FIRST WAVE WIL BE APPROACHING THE AREA FROM LK WINNIPEG AND BE
LOCATED OVER THE ARROWHEAD OF MN AT THE START OF THE PERIOD. THIS
SHORTWAVE AND ASSOCIATED COLD FRONT WILL WORK ACROSS UPPER MI DURING
THE DAYTIME HOURS ON MON AND THEN MOVE INTO NRN LOWER MI ON MON
NIGHT. DO THINK THERE WILL BE SOME ONGOING SHOWERS OVER THE NW HALF
OF THE CWA MON MORNING...NEAR THE SHORTWAVE TRACKING THROUGH SW
ONTARIO AND INTO NW LK SUPERIOR AND ON THE NOSE OF THE H850 WAA.
THUNDER IS ALSO POSSIBLE AS THIS AREA WILL ALSO BE ALONG BETTER
H700-500 LAPSE RATES AND MUCAPE VALUES OF 500-1000 J/KG. WITH THE
MAIN UPPER FORCING SHIFTING TO THE ENE...EXPECT THE REMAINING
-SHRA/TSRA TO FOLLOW SUIT THROUGH THE REST OF THE MORNING. THEN...AS
THE COLD FRONT SLIDES SE ACROSS THE AREA MON AFTN DURING PEAK
HEATING...THINK THE BEST PCPN CHANCES WILL OCCUR OVER CNTRL/ERN
UPPER MI. HAVE CONTINUED THE LOW END LIKELY POPS ...BUT DID TREND
THEM A LITTLE FARTHER SW INTO THE BETTER INSTABILITY. MAIN CONCERN
WITH THE HIGHER POPS IS THAT THE BETTER FORCING WILL BE STAYING OUT
OVER LK SUPERIOR...BUT THE INSTABILITY AND COLD FRONT SHOULD ALLOW
CONVECTION TO DEVELOP.
ML CAPE VALUES ARE EXPECTED TO BE IN THE 500-1250 J/KG RANGE OVER
THE INTERIOR PORTIONS OF THE CWA...ALONG WITH 0-6KM BULK SHEAR
VALUES IN THE 30-35KT RANGE ALONG AND JUST AHEAD OF THE
SHORTWAVE...WILL LEAD TO THE POTENTIAL FOR SOME STRONG TO SEVERE
WEATHER WITH THESE THUNDERSTORMS. NCAPE VALUES IN THE
.1-.15 RANGE INDICATE THE POTENTIAL FOR SOME HAIL...ALONG WITH HAIL
CAPE VALUES EXCEEDING 500 J/KG. BUT DIFFERING MOISTURE PROFILES AND
TIMING OF MID LEVEL DRY AIR TO AID DOWNDRAFTS LEADS TO UNCERTAINTY
ON STRONG WIND POTENTIAL. IF DRY AIR ARRIVES EARLY ENOUGH...AREA
WOULD SEE DCAPE VALUES PEAK TOWARDS 1000 J/KG AND INCREASE WIND
POTENTIAL. AS THE FRONT SHIFTS TO THE ESE THROUGH THE AFTN AND
EVENING...EXPECT A DIMINISHING TREND OVER THE CENTRL DURING THE
EARLY EVENING AND ENDING OVERNIGHT OVER THE EAST.
BEHIND THIS FIRST WAVE...WEAK UPPER RIDGING IN THE
PREDOMINATELY NW FLOW WILL ALLOW HIGH PRESSURE TO BUILD IN
AFTER OVERNIGHT MON NIGHT AND REMAIN INTO TUES EVENING. ECMWF DROPS
A LOT OF LLVL MOISTURE IN BEHIND THE FRONT/SHORTWAVE SO HAVE
LINGERED PARTLY CLOUDY SKIES THROUGH MONDAY NIGHT TO ACCOUNT FOR
THIS. IF IT DOESN/T OCCUR OVER THE W...COULD SEE RADIATIONAL FOG
DEVELOP...ESPECIALLY IN LOCATIONS THAT RECEIVE RAIN. EXPECT DIURNAL
CU TO DEVELOP ON TUES WITH LINGERING H850 MOISTURE OVER INTERIOR
LOCATIONS...BUT DRY AIR ALOFT AND SUBSIDENCE SHOULD KEEP CLOUDS FROM
BECOMING TOO WIDESPREAD.
AS THE HIGH BEGINS TO SHIFT SE ON WED...NEXT WAVE WILL QUICKLY DIVE
SE OUT OF ALBERTA AND INTO THE UPPER GREAT LKS WED NIGHT.
MEANWHILE...ASSOCIATED SFC LOW WILL DEVELOP NEAR LK WINNIPEG AND
TRACK ESE ACROSS LK SUPERIOR. H850-700 WAA AHEAD OF THIS WAVE COULD
KICK OFF A FEW SHOWERS OVER THE W LATE WED AFTN INTO WED
EVENING...BUT BEST CHANCES WILL BE WITH THE SHORTWAVE OVERNIGHT. AT
THIS POINT...THERE IS SOME POTENTIAL FOR STRONGER STORMS WITH
HAIL...AS 1-6KM BULK SHEAR VALUES ARE AROUND 30KTS AND MUCAPE AROUND
1-2K J/KG. THIS WILL BE AIDED BY STEEPER MID LVL LAPSE RATES
FATTENING UP THE CAPE SOME...BUT MAY NOT BE STRONG ENOUGH TO PUSH
STORMS INTO GOOD HAIL GROWTH AREA. BEST FORCING/MOISTURE WITH THIS
WAVE WILL ONCE AGAIN BE OVER LK SUPERIOR AND HAVE TRENDED POPS LOWER
TO THE S. DEPENDING ON HOW QUICKLY THE FRONT CAN SLIDE THROUGH...MAY
SEE SOME LINGERING SHOWERS/THUNDERSTORMS OVER THE SE HALF OF THE CWA
THURS AND WILL CONTINUE TO MENTION CHANCE POPS.
ANOTHER HIGH PRESSURE RIDGE WILL MOVE IN BEHIND THIS SECOND
WAVE...WHICH SHOULD LEAD TO GENERALLY DRY CONDITIONS THURS NIGHT
INTO FRI MORNING. THEN THE THIRD...AND LIKELY MOST
POTENT...SHORTWAVE AND ASSOCIATED SFC LOW WILL SLIDE ESE OUT OF NRN
ALBERTA AND INTO ONTARIO FRI NIGHT AND OVER JAMES BAY BY SAT AFTN.
SRN EDGE OF THIS SHORTWAVE TROUGH WILL AFFECT THE UPPER GREAT
LKS...ALONG WITH THE RELATED COLD FRONT. THE DYNAMICS AND MOISTURE
ASSOCIATED WITH THIS WAVE LEADS TO BUMPING POPS UP TO AT LEAST
CHANCES ON FRIDAY NIGHT. INSTABILITY AT THIS POINT LOOKS TO BE
LIMITED DUE TO THE SHORT PERIOD OF RETURN FLOW BEHIND THE EXITING
SFC RIDGE...BUT WITH THE AREA ON THE NRN EDGE OF THE INSTABILITY
AND SYSTEM DYNAMICS POINTS TO THUNDER POTENTIAL.
OVERALL...TEMPERATURES FOR THE PERIOD LOOK TO BE FAIRLY
NORMAL...WITH HIGHS IN THE 70S AND LOWER 80S MOST DAYS. THE THIRD
WAVE SHOULD LEAD TO SLIGHTLY COOLER VALUES FOR THE SECOND HALF OF
NEXT WEEKEND AND THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 132 AM EDT SUN JUL 29 2012
VFR CONDITIONS TO CONTINUE THROUGH THE FORECAST PERIOD. LIGHT AND
VARIABLE WINDS OVERNIGHT WILL BECOME SOUTH AT LESS THAN 10 KNOTS
AFTER SUNRISE AS SFC PRESSURE GRADIENT BEGINS TO SLOWLY TIGHTEN UP
AHEAD OF A WEAK LOW PRESSURE SYSTEM THAT WILL MOVE INTO THE REGION
ON MONDAY. THIS FEATURE IS EXPECTED TO PRODUCE WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS OVER KIWD AND KCMX AFTER 02Z MONDAY BUT
THE PROBABILITIES ARE LOW ENOUGH AT THIS TIME TO WARRANT NOT
INCLUDING A MENTION IN THE FORECASTS FOR THOSE SITES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 AM EDT SUN JUL 29 2012
EXPECT WINDS AOB 20 KTS THRU THIS FORECAST PERIOD WITH RELATIVELY
WEAK PRES GRADIENT TYPICAL OF MID SUMMER DOMINATING. LO PRES TROF
PASSAGES ON MON AND WED/THU WILL BRING THE THREAT OF TS DURING THOSE
TIMES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...SRF
AVIATION...RJT
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED FOR 18Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1240 PM CDT SUN JUL 29 2012
.DISCUSSION...ISSUED 415 AM CDT
SHORT WAVE NEAR WILLMAR THIS MORNING HAS DRIVEN SHOWERS ACROSS THE
AREA THIS PAST NIGHT. ELEVATED SHOWERS ACROSS WRN WI OVER TO THE
NRN TWIN CITIES ARE WITHIN A ZONE OF WEAK FGEN/ISENTROPIC LIFT
AROUND H6...ACTIVITY WEST OF THE CITIES IS ASSOCIATED WITH THE
SHORTWAVE...WHILE MOST ROBUST AREA OF CONVECTION ACROSS SOUTH
CENTRAL MINNESOTA IS ON THE NOSE OF THE LLJ. THE RAP SHOWS THIS
UPPER WAVE REACHING LA CROSSE BY 15Z...WITH ASSOCIATED FORCING
MOVING TO THE SOUTHEAST THROUGH THE REST OF THE MORNING. SRN MN
CONVECTION WILL CERTAINLY CONTINUE TO FOCUS BRUNT OF PRECIP TO THE
SOUTH...BUT SHOULD CONTINUE TO SEE LIGHT SHOWERS FOLLOW THE H7/H5
LOW SE ACROSS THE AREA THIS MORNING...WITH A MAJORITY OF RAIN
FALLING ALONG AND SOUTH OF I-94. BASED ON RAP TIMING OF THE
SHORTWAVE AND REFLECTIVITY FORECASTS FROM MOST CAMS...EXPECT MOST
OF THIS PRECIP TO BE OUT OF THE MPX CWFA BY 15Z. IN THE RAINS
WAKE...SKIES WILL BE CLEARING OUT FROM WEST TO EAST. H85 TEMPS
WILL RANGE FROM AROUND +22C WEST TO +16 EAST...WHICH SHOULD ALLOW
FOR LOWER 90S TO LOWER 80S FOR HIGHS RESPECTIVELY.
FOR TONIGHT...STRONG WAVE CURRENTLY SPINNING ACROSS SRN SASK WILL
RUN ALONG THE MN/ONTARIO BORDER...DRIVING A COLD FRONT INTO NRN
MN. CAMS AND SREF PROBS ALL SIMILAR WITH DEVELOPING SCT STORMS
ALONG THE FRONT THIS AFTERNOON FROM ERN NODAK INTO NW MN. THIS
FRONT WILL BE MOVING INTO CENTRAL MN BY 12Z MONDAY...SO INTRODUCED
SOME SMALL POPS ACROSS CENTRAL MN LATE TONIGHT TO ACCOUNT FOR
THAT. DURING THE DAY MONDAY...THIS FRONT WILL DROP ACROSS THE
AREA...EXITING THE S/SE MPX CWFA BETWEEN 21Z AND 00Z. BEST FLOW AT
H85 AND CONVERGENCE ALONG THE BOUNDARY STILL PEGGED TO BE ACROSS
THE U.P. OF MICH INTO NRN WI...WHERE GREATEST POTENTIAL FOR STORMS
WILL EXIST. CONTINUED A NARROW RIBBON OF SLIGHTS ALONG THE FRONT
MONDAY AFTERNOON WITH THE NAM ADVERTISING 2-3000 J/KG OF MUCAPE
ALONG THE FRONT. GIVEN THE FRONTS EXPECTED MOVEMENT...DID TRIM
BACK HOW FAR NORTH POPS ARE MENTIONED MONDAY AFTERNOON. ALSO LOOKS
WARM AGAIN MONDAY...WITH H85 TEMPS WARMING INTO THE 20S C FOR MOST
OF THE AREA...CONTINUED TO ADVERTISE UPPER 80S TO LOWER 90S HIGHS
MONDAY AFTERNOON...WITH 90S CREEPING UP TO ABOUT I-94.
FOR THE REST OF THE FORECAST...WILL BE REMAINING NORTH OF THE MAIN
UPPER RIDGE...WELL WITHIN THE JET STREAMS TERRITORY. STILL LOOKING
AT TWO POTENTIAL ACTIVE PERIODS IN THE TUESDAY THROUGH SUNDAY
TIMEFRAME. THE FIRST WILL BE ANOTHER WEAK NW FLOW WAVE THE MODELS
SHOW CRESTING THE RIDGE WEDNESDAY INTO WEDNESDAY NIGHT...SENDING A
VERY WEAK BOUNDARY ACROSS THE REGION. LIKE MONDAYS FRONT...H85
FLOW WILL BE LACKING WITH THE WEDNESDAY WAVE...AND PRECIP CHANCES
ARE LOOKING SCANT AT BEST WITH THIS WAVE...SO CONTINUED TO CAP
POPS AT 40 PERCENT...WITH BEST CHANCES RUNNING ACROSS CENTRAL MN
INTO WRN WI...WHICH IS WHERE THE ECMWF SHOWS THE SRN END OF A LLJ
WORKING THROUGH.
SHOULD SEE ANOTHER BREAK FROM THE PRECIP ACROSS THE AREA
THURSDAY...BEFORE A MORE SIGNIFICANT UPPER WAVE MOVES ACROSS THE
UPPER MS VALLEY SOMETIME ON FRIDAY /ECMWF AND GEM/ OR SATURDAY
/GFS/. ECMWF IS MOST AGGRESSIVE WITH THE WAVE...BRING A NEUTRAL TO
NEG TILTED TROUGH THROUGH...WITH THE GFS SHOWING A WEAKER
POSITIVELY TILTED TROUGH WORKING THROUGH SATURDAY. GIVEN TIMING
DIFFERENCES...BLENDING PROCEDURE ENDED UP SMEARING CHANCE POPS
ACROSS BOTH DAYS. HOWEVER...DESPITE THE TIMING DIFFERENCES...BOTH
THE GFS AND ECMWF SHOW THIS FRONT PACKING QUITE A PUNCH IN TERMS
OF COOLER/DRIER AIR BEHIND IT...WITH BOTH ADVERTISING A 1020 MB
HIGHS SETTLING IN BEHIND THIS SYSTEM. TILL THEN THOUGH...HIGHS IN
THE MID 80S TO LOWER 90S WILL BE THE NORM.
.CLIMATE...
QUICK CHECK THROUGH THE CLIMATE DATA FOR THE TWIN CITIES FOR
NUMBER OF DAYS IN A MONTH WHERE HIGHS WERE BELOW 80 SHOWS THAT
THERE HAS NEVER BEEN A MONTH IN THE TWIN CITIES WHERE THERE WAS
NOT AT LEAST ONE DAY WITH A HIGH LESS THAN 80 /JULY OF 1936 AND
1916 BOTH HAD ONE SUB 80 DEGREE DAY/. TO THIS POINT...THE
"COLDEST" HIGH THIS MONTH WAS AN 80 ON THE 27TH. BASED ON CURRENT
FORECAST...THIS JULY LOOKS LIKE IT WILL BE THE FIRST MONTH IN
RECORDED HISTORY FOR THE TWIN CITIES WHERE WE FAILED TO SEE AT
LEAST ONE DAY LESS THAN 80. THE LAST SUB 80 HIGH WAS BACK ON JUNE
25TH.
&&
.AVIATION.../18Z TAF ISSUANCE/
VORT WHICH BROUGHT RATHER WDSPRD RAINS THIS MRNG NOW SE OF MSP NEAR
RGK TAKING PCPN WITH IT. SOME SUBSIDENCE IMMEDIATELY BEHIND THIS
FEATURE HAS SUPPRESSED CU DVLPMT...BUT CU HAS BEEN DEVELPING ACROSS
RWF/STC AND WILL BE DEVELOPING ACROSS REMAINING TAFS NEXT 2-3 HOURS.
SOME THREAT OF STATUS/FOG DEVELOPMENT OVERNIGHT...BUT INCREASING
MID/HI CLDS AND INCREASING SWLY GRADIENT AHD OF INCOMING CDFNT MAY
LIMIT DEVELOPMENT SOMEWHAT. BEST POTENTIAL FOR IFR/MVFR SHUD BE IN
EAU. SCT SHWRS/PSBL TSTM 08Z-12Z AXN/STC AHD OF CDFNT. LOOK FOR
WIND GUSTS TO 20 KTS BHND CDFNT.
KMSP...MID CLDS ARE THINNING AS VORT DROPS SE OF AREA. SHUD SEE VFR
CU DEVELOPING NEXT 1-2 HOURS. SOME THREAT OF MVFR CIGS/VSBYS ARND
08Z. HOWEVER...INCREASING UPSTREAM MID/HI CLDS AND INCREASING SW
GRADIENT AHD OF APRCHG CDFNT COULD PREVENT THIS DEVELOPMENT.
//OUTLOOK
MONDAY... VFR.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR EXPECTED.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/BAP
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
610 AM CDT SUN JUL 29 2012
.UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...
SHORT WAVE NEAR WILLMAR THIS MORNING HAS DRIVEN SHOWERS ACROSS THE
AREA THIS PAST NIGHT. ELEVATED SHOWERS ACROSS WRN WI OVER TO THE
NRN TWIN CITIES ARE WITHIN A ZONE OF WEAK FGEN/ISENTROPIC LIFT
AROUND H6...ACTIVITY WEST OF THE CITIES IS ASSOCIATED WITH THE
SHORTWAVE...WHILE MOST ROBUST AREA OF CONVECTION ACROSS SOUTH
CENTRAL MINNESOTA IS ON THE NOSE OF THE LLJ. THE RAP SHOWS THIS
UPPER WAVE REACHING LA CROSSE BY 15Z...WITH ASSOCIATED FORCING
MOVING TO THE SOUTHEAST THROUGH THE REST OF THE MORNING. SRN MN
CONVECTION WILL CERTAINLY CONTINUE TO FOCUS BRUNT OF PRECIP TO THE
SOUTH...BUT SHOULD CONTINUE TO SEE LIGHT SHOWERS FOLLOW THE H7/H5
LOW SE ACROSS THE AREA THIS MORNING...WITH A MAJORITY OF RAIN
FALLING ALONG AND SOUTH OF I-94. BASED ON RAP TIMING OF THE
SHORTWAVE AND REFLECTIVITY FORECASTS FROM MOST CAMS...EXPECT MOST
OF THIS PRECIP TO BE OUT OF THE MPX CWFA BY 15Z. IN THE RAINS
WAKE...SKIES WILL BE CLEARING OUT FROM WEST TO EAST. H85 TEMPS
WILL RANGE FROM AROUND +22C WEST TO +16 EAST...WHICH SHOULD ALLOW
FOR LOWER 90S TO LOWER 80S FOR HIGHS RESPECTIVELY.
FOR TONIGHT...STRONG WAVE CURRENTLY SPINNING ACROSS SRN SASK WILL
RUN ALONG THE MN/ONTARIO BORDER...DRIVING A COLD FRONT INTO NRN
MN. CAMS AND SREF PROBS ALL SIMILAR WITH DEVELOPING SCT STORMS
ALONG THE FRONT THIS AFTERNOON FROM ERN NODAK INTO NW MN. THIS
FRONT WILL BE MOVING INTO CENTRAL MN BY 12Z MONDAY...SO INTRODUCED
SOME SMALL POPS ACROSS CENTRAL MN LATE TONIGHT TO ACCOUNT FOR
THAT. DURING THE DAY MONDAY...THIS FRONT WILL DROP ACROSS THE
AREA...EXITING THE S/SE MPX CWFA BETWEEN 21Z AND 00Z. BEST FLOW AT
H85 AND CONVERGENCE ALONG THE BOUNDARY STILL PEGGED TO BE ACROSS
THE U.P. OF MICH INTO NRN WI...WHERE GREATEST POTENTIAL FOR STORMS
WILL EXIST. CONTINUED A NARROW RIBBON OF SLIGHTS ALONG THE FRONT
MONDAY AFTERNOON WITH THE NAM ADVERTISING 2-3000 J/KG OF MUCAPE
ALONG THE FRONT. GIVEN THE FRONTS EXPECTED MOVEMENT...DID TRIM
BACK HOW FAR NORTH POPS ARE MENTIONED MONDAY AFTERNOON. ALSO LOOKS
WARM AGAIN MONDAY...WITH H85 TEMPS WARMING INTO THE 20S C FOR MOST
OF THE AREA...CONTINUED TO ADVERTISE UPPER 80S TO LOWER 90S HIGHS
MONDAY AFTERNOON...WITH 90S CREEPING UP TO ABOUT I-94.
FOR THE REST OF THE FORECAST...WILL BE REMAINING NORTH OF THE MAIN
UPPER RIDGE...WELL WITHIN THE JET STREAMS TERRITORY. STILL LOOKING
AT TWO POTENTIAL ACTIVE PERIODS IN THE TUESDAY THROUGH SUNDAY
TIMEFRAME. THE FIRST WILL BE ANOTHER WEAK NW FLOW WAVE THE MODELS
SHOW CRESTING THE RIDGE WEDNESDAY INTO WEDNESDAY NIGHT...SENDING A
VERY WEAK BOUNDARY ACROSS THE REGION. LIKE MONDAYS FRONT...H85
FLOW WILL BE LACKING WITH THE WEDNESDAY WAVE...AND PRECIP CHANCES
ARE LOOKING SCANT AT BEST WITH THIS WAVE...SO CONTINUED TO CAP
POPS AT 40 PERCENT...WITH BEST CHANCES RUNNING ACROSS CENTRAL MN
INTO WRN WI...WHICH IS WHERE THE ECMWF SHOWS THE SRN END OF A LLJ
WORKING THROUGH.
SHOULD SEE ANOTHER BREAK FROM THE PRECIP ACROSS THE AREA
THURSDAY...BEFORE A MORE SIGNIFICANT UPPER WAVE MOVES ACROSS THE
UPPER MS VALLEY SOMETIME ON FRIDAY /ECMWF AND GEM/ OR SATURDAY
/GFS/. ECMWF IS MOST AGGRESSIVE WITH THE WAVE...BRING A NEUTRAL TO
NEG TILTED TROUGH THROUGH...WITH THE GFS SHOWING A WEAKER
POSITIVELY TILTED TROUGH WORKING THROUGH SATURDAY. GIVEN TIMING
DIFFERENCES...BLENDING PROCEDURE ENDED UP SMEARING CHANCE POPS
ACROSS BOTH DAYS. HOWEVER...DESPITE THE TIMING DIFFERENCES...BOTH
THE GFS AND ECMWF SHOW THIS FRONT PACKING QUITE A PUNCH IN TERMS
OF COOLER/DRIER AIR BEHIND IT...WITH BOTH ADVERTISING A 1020 MB
HIGHS SETTLING IN BEHIND THIS SYSTEM. TILL THEN THOUGH...HIGHS IN
THE MID 80S TO LOWER 90S WILL BE THE NORM.
.CLIMATE...
QUICK CHECK THROUGH THE CLIMATE DATA FOR THE TWIN CITIES FOR
NUMBER OF DAYS IN A MONTH WHERE HIGHS WERE BELOW 80 SHOWS THAT
THERE HAS NEVER BEEN A MONTH IN THE TWIN CITIES WHERE THERE WAS
NOT AT LEAST ONE DAY WITH A HIGH LESS THAN 80 /JULY OF 1936 AND
1916 BOTH HAD ONE SUB 80 DEGREE DAY/. TO THIS POINT...THE
"COLDEST" HIGH THIS MONTH WAS AN 80 ON THE 27TH. BASED ON CURRENT
FORECAST...THIS JULY LOOKS LIKE IT WILL BE THE FIRST MONTH IN
RECORDED HISTORY FOR THE TWIN CITIES WHERE WE FAILED TO SEE AT
LEAST ONE DAY LESS THAN 80. THE LAST SUB 80 HIGH WAS BACK ON JUNE
25TH.
&&
.AVIATION.../12Z TAF ISSUANCE/
MAIN CONCERN EARLY IS THREAT OF MVFR CIGS/VSBYS AS SHRA MOVES
THROUGH. CONTINUED THE TREND OF DRIVING SYSTEM INTO WISCONSIN AFTER
14Z...ENDING BY 17Z AT KEAU. WILL LIKELY SEE PERIOD OF MVFR CIGS
OVER EASTERN AREAS THROUGH 18Z. THEN SHOULD SEE CUMULUS LIFT INTO
THE AFTERNOON AND DISSIPATE BY EVENING. SOUTHWEST WINDS AHEAD OF
RAIN AREA...THEN BECOMING LIGHT SOUTHEAST OVER MUCH OF THE AREA THE
REST OF THE DAY. OVERNIGHT...WITH LIGHT WINDS AND MAINLY HIGH
CLOUDS...COULD SEE FOG DEVELOP...ESPECIALLY OVER EASTERN AREAS/WI.
MENTIONED FOR MVFR VSBYS IN BR AT KSTC/KRNH AND KEAU...MAINLY
09Z-12Z. COLD FRONT SWEEPS SOUTHEAST AND MOVES THROUGH KMSP BY 18Z
MONDAY. RIGHT NOW...LOOKS LIKE A DRY FROPA WITH WIND SHIFTING TO
THE WEST/NORTHWEST.
KMSP...WAVE MOVING THROUGH THE AREA THROUGH 13Z-14Z...WITH POSSIBLE
TEMPO MVFR CONDITIONS. THEN CLOUDS SHOULD THIN WITH SOME CUMULUS
EXPECTED INTO THE AFTERNOON. CLEARING BY LATE AFTERNOON WITH MORE
MID/HIGH CLOUDS INTO THE AREA LATER TONIGHT. FROPA BY 18Z MONDAY
WITH WINDS SHIFTING TO THE NORTHWEST AND POSSIBLY GUSTY INTO THE
AFTERNOON.
//OUTLOOK
MONDAY... BRIEF MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA IN WI.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR EXPECTED.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/DE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
415 AM CDT SUN JUL 29 2012
.DISCUSSION...
SHORT WAVE NEAR WILLMAR THIS MORNING HAS DRIVEN SHOWERS ACROSS THE
AREA THIS PAST NIGHT. ELEVATED SHOWERS ACROSS WRN WI OVER TO THE
NRN TWIN CITIES ARE WITHIN A ZONE OF WEAK FGEN/ISENTROPIC LIFT
AROUND H6...ACTIVITY WEST OF THE CITIES IS ASSOCIATED WITH THE
SHORTWAVE...WHILE MOST ROBUST AREA OF CONVECTION ACROSS SOUTH
CENTRAL MINNESOTA IS ON THE NOSE OF THE LLJ. THE RAP SHOWS THIS
UPPER WAVE REACHING LA CROSSE BY 15Z...WITH ASSOCIATED FORCING
MOVING TO THE SOUTHEAST THROUGH THE REST OF THE MORNING. SRN MN
CONVECTION WILL CERTAINLY CONTINUE TO FOCUS BRUNT OF PRECIP TO THE
SOUTH...BUT SHOULD CONTINUE TO SEE LIGHT SHOWERS FOLLOW THE H7/H5
LOW SE ACROSS THE AREA THIS MORNING...WITH A MAJORITY OF RAIN
FALLING ALONG AND SOUTH OF I-94. BASED ON RAP TIMING OF THE
SHORTWAVE AND REFLECTIVITY FORECASTS FROM MOST CAMS...EXPECT MOST
OF THIS PRECIP TO BE OUT OF THE MPX CWFA BY 15Z. IN THE RAINS
WAKE...SKIES WILL BE CLEARING OUT FROM WEST TO EAST. H85 TEMPS
WILL RANGE FROM AROUND +22C WEST TO +16 EAST...WHICH SHOULD ALLOW
FOR LOWER 90S TO LOWER 80S FOR HIGHS RESPECTIVELY.
FOR TONIGHT...STRONG WAVE CURRENTLY SPINNING ACROSS SRN SASK WILL
RUN ALONG THE MN/ONTARIO BORDER...DRIVING A COLD FRONT INTO NRN
MN. CAMS AND SREF PROBS ALL SIMILAR WITH DEVELOPING SCT STORMS
ALONG THE FRONT THIS AFTERNOON FROM ERN NODAK INTO NW MN. THIS
FRONT WILL BE MOVING INTO CENTRAL MN BY 12Z MONDAY...SO INTRODUCED
SOME SMALL POPS ACROSS CENTRAL MN LATE TONIGHT TO ACCOUNT FOR
THAT. DURING THE DAY MONDAY...THIS FRONT WILL DROP ACROSS THE
AREA...EXITING THE S/SE MPX CWFA BETWEEN 21Z AND 00Z. BEST FLOW AT
H85 AND CONVERGENCE ALONG THE BOUNDARY STILL PEGGED TO BE ACROSS
THE U.P. OF MICH INTO NRN WI...WHERE GREATEST POTENTIAL FOR STORMS
WILL EXIST. CONTINUED A NARROW RIBBON OF SLIGHTS ALONG THE FRONT
MONDAY AFTERNOON WITH THE NAM ADVERTISING 2-3000 J/KG OF MUCAPE
ALONG THE FRONT. GIVEN THE FRONTS EXPECTED MOVEMENT...DID TRIM
BACK HOW FAR NORTH POPS ARE MENTIONED MONDAY AFTERNOON. ALSO LOOKS
WARM AGAIN MONDAY...WITH H85 TEMPS WARMING INTO THE 20S C FOR MOST
OF THE AREA...CONTINUED TO ADVERTISE UPPER 80S TO LOWER 90S HIGHS
MONDAY AFTERNOON...WITH 90S CREEPING UP TO ABOUT I-94.
FOR THE REST OF THE FORECAST...WILL BE REMAINING NORTH OF THE MAIN
UPPER RIDGE...WELL WITHIN THE JET STREAMS TERRITORY. STILL LOOKING
AT TWO POTENTIAL ACTIVE PERIODS IN THE TUESDAY THROUGH SUNDAY
TIMEFRAME. THE FIRST WILL BE ANOTHER WEAK NW FLOW WAVE THE MODELS
SHOW CRESTING THE RIDGE WEDNESDAY INTO WEDNESDAY NIGHT...SENDING A
VERY WEAK BOUNDARY ACROSS THE REGION. LIKE MONDAYS FRONT...H85
FLOW WILL BE LACKING WITH THE WEDNESDAY WAVE...AND PRECIP CHANCES
ARE LOOKING SCANT AT BEST WITH THIS WAVE...SO CONTINUED TO CAP
POPS AT 40 PERCENT...WITH BEST CHANCES RUNNING ACROSS CENTRAL MN
INTO WRN WI...WHICH IS WHERE THE ECMWF SHOWS THE SRN END OF A LLJ
WORKING THROUGH.
SHOULD SEE ANOTHER BREAK FROM THE PRECIP ACROSS THE AREA
THURSDAY...BEFORE A MORE SIGNIFICANT UPPER WAVE MOVES ACROSS THE
UPPER MS VALLEY SOMETIME ON FRIDAY /ECMWF AND GEM/ OR SATURDAY
/GFS/. ECMWF IS MOST AGGRESSIVE WITH THE WAVE...BRING A NEUTRAL TO
NEG TILTED TROUGH THROUGH...WITH THE GFS SHOWING A WEAKER
POSITIVELY TILTED TROUGH WORKING THROUGH SATURDAY. GIVEN TIMING
DIFFERENCES...BLENDING PROCEDURE ENDED UP SMEARING CHANCE POPS
ACROSS BOTH DAYS. HOWEVER...DESPITE THE TIMING DIFFERENCES...BOTH
THE GFS AND ECMWF SHOW THIS FRONT PACKING QUITE A PUNCH IN TERMS
OF COOLER/DRIER AIR BEHIND IT...WITH BOTH ADVERTISING A 1020 MB
HIGHS SETTLING IN BEHIND THIS SYSTEM. TILL THEN THOUGH...HIGHS IN
THE MID 80S TO LOWER 90S WILL BE THE NORM.
.CLIMATE...
QUICK CHECK THROUGH THE CLIMATE DATA FOR THE TWIN CITIES FOR
NUMBER OF DAYS IN A MONTH WHERE HIGHS WERE BELOW 80 SHOWS THAT
THERE HAS NEVER BEEN A MONTH IN THE TWIN CITIES WHERE THERE WAS
NOT AT LEAST ONE DAY WITH A HIGH LESS THAN 80 /JULY OF 1936 AND
1916 BOTH HAD ONE SUB 80 DEGREE DAY/. TO THIS POINT...THE
"COLDEST" HIGH THIS MONTH WAS AN 80 ON THE 27TH. BASED ON CURRENT
FORECAST...THIS JULY LOOKS LIKE IT WILL BE THE FIRST MONTH IN
RECORDED HISTORY FOR THE TWIN CITIES WHERE WE FAILED TO SEE AT
LEAST ONE DAY LESS THAN 80. THE LAST SUB 80 HIGH WAS BACK ON JUNE
25TH.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN CONCERN WILL BE STORMS LATE TONIGHT. ELEVATED INSTABILITY
ARCING FROM WEST CENTRAL MN INTO WESTERN WISCONSIN SO HAVE
MENTIONED THUNDER FROM AXN/STC TO RNH/EAU. WILL KEEP THUNDER GOING
FOR JUST TWO OR THREE HOURS AT THESE SITES BUT THE CONCERN WILL BE
FOR MORE DEVELOPMENT. NOT MUCH OF A LOW LEVEL JET IN THIS AREA SO
HAVE TRIED TO KEEP THE THUNDER THREAT AT THOSE LOCALES LIMITED TO
JUST THOSE FEW HOURS. CONFIDENCE A LITTLE LESS THAN AVERAGE ON
THIS THOUGH.
OTHER AREA OF STORMS IN SERN SD INTO SRN MN. INFLUENCE OF LOW
LEVEL JET MORE SIGNIFICANT IN THIS AREA. RWF COULD SEE THUNDER
MUCH OF THE NIGHT ONCE IT ARRIVES AFTER 07Z.
FOG WILL ALSO BE A CONCERN WITH HUMID BOUNDARY LAYER AND LIGHT
WINDS. ONCE PRECIP ENDS SUNDAY AROUND 15Z...SHOULD SEE JUST
SCATTERED CLOUDS WITH PLENTY OF SUBSIDENCE BEHIND SHORT WAVE.
KMSP... SOME THUNDER THREAT LATE TONIGHT BUT WILL NOT BE SHOCKED
IF NORTHERN ARC OF STORMS STAYS NORTH WHILE SWRN STORMS STAY IN
SOUTHERN MN. I.E. SOME POTENTIAL FOR KMSP TO BE BETWEEN AREAS BUT
STILL NEED TO MENTION THUNDER FOR A COUPLE HOURS SINCE LOW LEVEL
JET DOES HAVE A BRIEF TIME WHEN IT REACHES FARTHER NORTH TOWARD KMSP.
CONFIDENCE LOW ON WHETHER THERE WILL BE THUNDER. ONCE SHORT WAVE
GOES BY... SKY SHOULD BE MOSTLY CLEAR THE REST OF SUNDAY AND
SUNDAY NIGHT.
//OUTLOOK
MONDAY... BRIEF MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
MONDAY NIGHT THROUGH TUESDAY NIGHT...VFR EXPECTED.
WEDNESDAY...MVFR CONDITIONS POSSIBLE WITH SHRA/TSRA.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/TDK
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1043 PM CDT MON JUL 30 2012
.SHORT TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TONIGHT)
EXTENSIVE AREA OF MID AND HIGH CLOUDS HAVE HELPED HOLD TEMPERATURES
BACK OVER MOST OF THE REGION TODAY. SURFACE REPORTS FROM THE LARGE
AREA OF RETURNS ON RADAR ARE MAINLY SPRINKLES. THIS IS BEING
GENERATED BY A VORT MAX THAT WILL MOVE SOUTH INTO THE SOUTHERN CWA
BY 00Z. THERE IS LITTLE LOW LEVEL FORCING ASSOCIATED WITH IT
ACCORDING TO THE RAP UNTIL AFTER 00Z...AND EVEN THEN IT IS QUITE
WEAK. THINK GOING SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS STILL
LOOKS OKAY GIVEN SLIGHTLY BETTER LOW LEVEL FORCING AND MORE
INSTABILITY. OTHERWISE CHANCES SHOULD DECREASE WITH TIME AS THE
LOW MOVES FARTHER SOUTH.
BRITT
&&
.LONG TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TUESDAY THROUGH NEXT MONDAY)
MAIN CONCERN ONCE AGAIN IS HEAT. HAVE ISSUED A HEAT ADVISORY JUST
FOR THE ST. LOUIS METRO AREA ON TUESDAY AFTERNOON AS IT CURRENTLY
LOOKS LIKE HEAT INDEX READINGS WILL CLIMB TO AROUND 105 DURING THE
AFTERNOON.
GFS/NAM ARE IN RELATIVELY GOOD AGREEMENT THAT A WEAK COLD FRONT WILL
BE MOVING SOUTH OUT OF THE UPPER MIDWEST INTO NORTHERN MISSOURI AND
CENTRAL ILLINOIS AROUND MIDDAY TOMORROW. DO NOT EXPECT MUCH CLOUDS
AND ANY RAIN CHANCES WITH THIS FRONT AS WE WILL LIE UNDER SUBSIDENCE
BETWEEN A SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES AND A
VORT MAX MOVING ACROSS SOUTHWEST MISSOURI. NAM FORECAST SOUNDINGS
SHOWING DEEP MIXING TO 700MB AHEAD OF THE FRONT WHICH SUPPORTS
GOING HIGHS WHICH ARE CLOSE TO THE NAM MOS TEMPERATURES WHICH HAVE
VERIFIED BETTER THIS SUMMER. DEWPOINTS SHOULD FALL INTO THE UPPER
50S TO LOWER 60S WITH THE MIXING...WHICH COMBINED WITH HIGHS
RISING TO AROUND 104 RESULT IN HEAT INDEX HIGHS BRIEFLY REACHING
105 TOMORROW AFTERNOON. TEMPERATURES ON WEDNESDAY LOOK TO BE NOT
AS WARM BEHIND THE FRONT...SO HEAT INDEX READINGS ARE EXPECTED TO
STAY BELOW 100 DEGREES. ANOTHER FRONT MOVES INTO NORTHERN MISSOURI
LATE THURSDAY/THURSDAY NIGHT...WITH THE GFS BRINGING IT THROUGH
THE AREA AND THE ECMWF KEEPING IT STALLED TO THE NORTH AS THE
UPPER FLOW BECOMES ZONAL. HAVE GONE WITH JUST A SLIGHT CHANCE FOR
SHOWERS/STORMS ON THURSDAY AND TEMPERATURES IN THE UPPER 90S WHICH
SHOULD RESULT IN HEAT INDEX READINGS BETWEEN 98-103.
GENERALLY STAYED WITH THE ECMWF OVER THE WEEKEND. SHOULD BE SOME
INCREASE IN LOW LEVEL FORCING AHEAD OF A COLD FRONT THAT WILL MOVE
ACROSS THE AREA ON SUNDAY...SO HAVE KEPT A CHANCE OF SHOWERS AND
THUNDERSTORMS GOING AHEAD OF IT. WITH 850MB TEMPS STAYING ABOVE
20C...HIGH TEMPERATURES SHOULD REMAIN ABOVE 90 THROUGH THE PERIOD.
BRITT
&&
.AVIATION...
ISSUED AT 1021 PM CDT MON JUL 30 2012
MID LEVEL CLOUDINESS OVER SRN AND W CNTRL MO WILL CONTINUE TO DROP
SWD LATE TGT...LIKELY ONLY IMPACTING COU TIL 06-07Z TUE...AND
REMAINING S-SW OF THE OTHER TAF SITES. SFC WINDS WILL BE LIGHT
TGT AS WEAK SFC RIDGE CENTERED OVER NERN MO SHIFTS SEWD. DUE TO
THE CLEARING SKY THIS EVNG ALONG WITH HIGH SFC DEWPOINTS AND LIGHT
WINDS THERE SHOULD BE SOME LIGHT PATCHY FOG LATE TGT AND EARLY
TUE MRNG WITH VSBYS DROPPING DOWN TO AROUND 3-5 MILES. A WEAK
COLD FRONT NOW OVER THE GREAT LAKES AND NRN PLAINS REGIONS WILL
DROP SEWD THROUGH OUR AREA ON TUE. ONLY ISOLATED SHOWERS/STORMS
EXPECTED ALONG THIS FRONT IN OUR AREA SO WILL LEAVE THE TAFS DRY
FOR NOW...PLUS LITTLE CLOUD COVER EXPECTED ON TUE. NWLY SFC WINDS
WILL INCREASE TUE AFTN AFTER FROPA...THEN BECOME N-NELY TUE EVNG
AS A SFC RIDGE BUILDS SEWD INTO THE GREAT LAKES REGION BEHIND THE
COLD FRONT.
SPECIFICS FOR KSTL...THE MID LEVEL CLOUD DECK HAS RECENTLY SHIFTED
S OF STL THIS EVNG AND SHOULD REMAIN S-SW THE REMAINDER OF THE
NIGHT WITH LITTLE CLOUD COVER EXPECTED FOR THE REST OF THE TAF
PERIOD. LIGHT SFC WINDS LATE TGT AND TUE MRNG COULD LEAD TO LIGHT
FOG OR HAZE LATE TGT AND EARLY TUE MRNG OF AROUND 5SM. THE SFC
WIND WILL INCREASE TO AROUND 10 KTS TUE AFTN FROM A NWLY DIRECTION
AFTER PASSAGE OF A WEAK COLD FRONT. COULD BE ISOLATED SHOWERS/STORMS
ALONG THIS FRONT IN THE ST LOUIS METRO AREA...BUT WILL LEAVE STL
TAF DRY FOR NOW AS CONVERGENCE ALONG FRONT SHOULD BE WEAK AND ANY
SIGNIFICANT MOISTURE SHOULD BE THIN OR SHALLOW. THE SFC WIND
SHOULD WEAKEN TUE NGT AND BECOME MORE NELY.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR JEFFERSON MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR MADISON IL-
MONROE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1031 PM CDT MON JUL 30 2012
.UPDATE...
ISSUED AT 1025 PM CDT MON JUL 30 2012
SHOWERS HAVE CONTINUED ACROSS SOUTHERN PORTIONS OF THE CWA IN
ASSOCIATION WITH A VORTMAX THAT DRIFTED SOUTH ACROSS THE REGION
THIS EVENING. HAVE TAPERED BACK ON POPS A BIT THIS EVENING AND
TWEAKED THE CLOUDCOVER...BUT OTHERWISE...NO MAJOR CHANGES ARE
NEEDED AS THE GOING FORECAST REMAINS ON TRACK.
JP
&&
.SHORT TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TONIGHT)
EXTENSIVE AREA OF MID AND HIGH CLOUDS HAVE HELPED HOLD TEMPERATURES
BACK OVER MOST OF THE REGION TODAY. SURFACE REPORTS FROM THE LARGE
AREA OF RETURNS ON RADAR ARE MAINLY SPRINKLES. THIS IS BEING
GENERATED BY A VORT MAX THAT WILL MOVE SOUTH INTO THE SOUTHERN CWA
BY 00Z. THERE IS LITTLE LOW LEVEL FORCING ASSOCIATED WITH IT
ACCORDING TO THE RAP UNTIL AFTER 00Z...AND EVEN THEN IT IS QUITE
WEAK. THINK GOING SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS STILL
LOOKS OKAY GIVEN SLIGHTLY BETTER LOW LEVEL FORCING AND MORE
INSTABILITY. OTHERWISE CHANCES SHOULD DECREASE WITH TIME AS THE
LOW MOVES FARTHER SOUTH.
BRIIT
&&
.LONG TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TUESDAY THROUGH NEXT MONDAY)
MAIN CONCERN ONCE AGAIN IS HEAT. HAVE ISSUED A HEAT ADVISORY JUST
FOR THE ST. LOUIS METRO AREA ON TUESDAY AFTERNOON AS IT CURRENTLY
LOOKS LIKE HEAT INDEX READINGS WILL CLIMB TO AROUND 105 DURING THE
AFTERNOON.
GFS/NAM ARE IN RELATIVELY GOOD AGREEMENT THAT A WEAK COLD FRONT WILL
BE MOVING SOUTH OUT OF THE UPPER MIDWEST INTO NORTHERN MISSOURI AND
CENTRAL ILLINOIS AROUND MIDDAY TOMORROW. DO NOT EXPECT MUCH CLOUDS
AND ANY RAIN CHANCES WITH THIS FRONT AS WE WILL LIE UNDER SUBSIDENCE
BETWEEN A SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES AND A
VORT MAX MOVING ACROSS SOUTHWEST MISSOURI. NAM FORECAST SOUNDINGS
SHOWING DEEP MIXING TO 700MB AHEAD OF THE FRONT WHICH SUPPORTS
GOING HIGHS WHICH ARE CLOSE TO THE NAM MOS TEMPERATURES WHICH HAVE
VERIFIED BETTER THIS SUMMER. DEWPOINTS SHOULD FALL INTO THE UPPER
50S TO LOWER 60S WITH THE MIXING...WHICH COMBINED WITH HIGHS
RISING TO AROUND 104 RESULT IN HEAT INDEX HIGHS BRIEFLY REACHING
105 TOMORROW AFTERNOON. TEMPERATURES ON WEDNESDAY LOOK TO BE NOT
AS WARM BEHIND THE FRONT...SO HEAT INDEX READINGS ARE EXPECTED TO
STAY BELOW 100 DEGREES. ANOTHER FRONT MOVES INTO NORTHERN MISSOURI
LATE THURSDAY/THURSDAY NIGHT...WITH THE GFS BRINGING IT THROUGH
THE AREA AND THE ECMWF KEEPING IT STALLED TO THE NORTH AS THE
UPPER FLOW BECOMES ZONAL. HAVE GONE WITH JUST A SLIGHT CHANCE FOR
SHOWERS/STORMS ON THURSDAY AND TEMPERATURES IN THE UPPER 90S WHICH
SHOULD RESULT IN HEAT INDEX READINGS BETWEEN 98-103.
GENERALLY STAYED WITH THE ECMWF OVER THE WEEKEND. SHOULD BE SOME
INCREASE IN LOW LEVEL FORCING AHEAD OF A COLD FRONT THAT WILL MOVE
ACROSS THE AREA ON SUNDAY...SO HAVE KEPT A CHANCE OF SHOWERS AND
THUNDERSTORMS GOING AHEAD OF IT. WITH 850MB TEMPS STAYING ABOVE
20C...HIGH TEMPERATURES SHOULD REMAIN ABOVE 90 THROUGH THE PERIOD.
BRITT
&&
.AVIATION...
ISSUED AT 543 PM CDT MON JUL 30 2012
MID LEVEL CLOUDINESS ALONG WITH PATCHY LIGHT RAIN OR JUST
SPRINKLES WAS MOVING THROUGH THE TAF SITES EARLY THIS EVNG AHEAD
OF A NW FLOW SHORTWAVE OVER N CNTRL NERN MO. THIS CLOUD COVER
ALONG WITH THE SPRINKLES WILL ADVECT S-SE OF THE TAF SITES LATER
THIS EVNG. WILL INCLUDE A TEMPO GROUP FOR -RA IN ALL THE TAF SITES
EXCEPT UIN TIL 01Z TUE. SFC WINDS WILL BE LIGHT TGT AS WEAK SFC
RIDGE CENTERED OVER NERN MO SHIFTS SEWD. WEAK COLD FRONT NOW OVER
THE GREAT LAKES AND NRN PLAINS REGIONS WILL DROP SEWD THROUGH OUR
AREA ON TUE. ONLY ISOLATED SHOWERS/STORMS EXPECTED ALONG THIS
FRONT IN OUR AREA SO WILL LEAVE THE TAFS DRY FOR NOW...PLUS LITTLE
CLOUD COVER EXPECTED ON TUE. DISCOUNTED THE GFS MOS CLOUD/VSBY
GUIDANCE WHICH HAS LOW LEVEL CLOUDS AND SOME FOG LATE TGT/EARLY
TUE MRNG...PREFER THE NAM MOS GUIDANCE. N-NWLY SFC WINDS WILL
INCREASE TUE AFTN AFTER FROPA.
SPECIFICS FOR KSTL...JUST SPRINKLES FROM MID LEVEL COUD DECK
EARLY THIS EVNG. THE MID LEVEL CLOUD DECK WILL SHIFT S-SE OF STL
BY LATE TGT WITH LITTLE CLOUD COVER EXPECTED FOR THE REST OF THE
TAF PERIOD. LIGHT SFC WINDS TGT AND TUE MRNG...THEN INCREASING
FROM A NWLY DIRECTION TUE AFTN TO AROUND 10 KTS AFTER PASSAGE OF A
WEAK COLD FRONT. COULD BE ISOLATED SHOWERS/STORMS ALONG THIS FRONT
IN THE ST LOUIS METRO AREA...BUT WILL LEAVE STL TAF DRY FOR NOW
AS CONVERGENCE ALONG FRONT SHOULD BE WEAK AND ANY SIGNIFICANT
MOISTURE SHOULD BE THIN OR SHALLOW. GFS MODEL APPEARS TO HAVE TOO
MUCH SFC/BOUNDARY LAYER MOISTURE LATE TGT AND EARLY TUE MRNG
LEADING TO ITS PERIOD OF LOW LEVEL CLOUDS AND FOG IN THE GFS MOS
GUIDANCE LATE TGT AND EARLY TUE MRNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR JEFFERSON MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR MADISON IL-
MONROE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
700 PM CDT MON JUL 30 2012
.SHORT TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TONIGHT)
EXTENSIVE AREA OF MID AND HIGH CLOUDS HAVE HELPED HOLD TEMPERATURES
BACK OVER MOST OF THE REGION TODAY. SURFACE REPORTS FROM THE LARGE
AREA OF RETURNS ON RADAR ARE MAINLY SPRINKLES. THIS IS BEING
GENERATED BY A VORT MAX THAT WILL MOVE SOUTH INTO THE SOUTHERN CWA
BY 00Z. THERE IS LITTLE LOW LEVEL FORCING ASSOCIATED WITH IT
ACCORDING TO THE RAP UNTIL AFTER 00Z...AND EVEN THEN IT IS QUITE
WEAK. THINK GOING SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS STILL
LOOKS OKAY GIVEN SLIGHTLY BETTER LOW LEVEL FORCING AND MORE
INSTABILITY. OTHERWISE CHANCES SHOULD DECREASE WITH TIME AS THE
LOW MOVES FARTHER SOUTH.
BRIIT
&&
.LONG TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TUESDAY THROUGH NEXT MONDAY)
MAIN CONCERN ONCE AGAIN IS HEAT. HAVE ISSUED A HEAT ADVISORY JUST
FOR THE ST. LOUIS METRO AREA ON TUESDAY AFTERNOON AS IT CURRENTLY
LOOKS LIKE HEAT INDEX READINGS WILL CLIMB TO AROUND 105 DURING THE
AFTERNOON.
GFS/NAM ARE IN RELATIVELY GOOD AGREEMENT THAT A WEAK COLD FRONT WILL
BE MOVING SOUTH OUT OF THE UPPER MIDWEST INTO NORTHERN MISSOURI AND
CENTRAL ILLINOIS AROUND MIDDAY TOMORROW. DO NOT EXPECT MUCH CLOUDS
AND ANY RAIN CHANCES WITH THIS FRONT AS WE WILL LIE UNDER SUBSIDENCE
BETWEEN A SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES AND A
VORT MAX MOVING ACROSS SOUTHWEST MISSOURI. NAM FORECAST SOUNDINGS
SHOWING DEEP MIXING TO 700MB AHEAD OF THE FRONT WHICH SUPPORTS
GOING HIGHS WHICH ARE CLOSE TO THE NAM MOS TEMPERATURES WHICH HAVE
VERIFIED BETTER THIS SUMMER. DEWPOINTS SHOULD FALL INTO THE UPPER
50S TO LOWER 60S WITH THE MIXING...WHICH COMBINED WITH HIGHS
RISING TO AROUND 104 RESULT IN HEAT INDEX HIGHS BRIEFLY REACHING
105 TOMORROW AFTERNOON. TEMPERATURES ON WEDNESDAY LOOK TO BE NOT
AS WARM BEHIND THE FRONT...SO HEAT INDEX READINGS ARE EXPECTED TO
STAY BELOW 100 DEGREES. ANOTHER FRONT MOVES INTO NORTHERN MISSOURI
LATE THURSDAY/THURSDAY NIGHT...WITH THE GFS BRINGING IT THROUGH
THE AREA AND THE ECMWF KEEPING IT STALLED TO THE NORTH AS THE
UPPER FLOW BECOMES ZONAL. HAVE GONE WITH JUST A SLIGHT CHANCE FOR
SHOWERS/STORMS ON THURSDAY AND TEMPERATURES IN THE UPPER 90S WHICH
SHOULD RESULT IN HEAT INDEX READINGS BETWEEN 98-103.
GENERALLY STAYED WITH THE ECMWF OVER THE WEEKEND. SHOULD BE SOME
INCREASE IN LOW LEVEL FORCING AHEAD OF A COLD FRONT THAT WILL MOVE
ACROSS THE AREA ON SUNDAY...SO HAVE KEPT A CHANCE OF SHOWERS AND
THUNDERSTORMS GOING AHEAD OF IT. WITH 850MB TEMPS STAYING ABOVE
20C...HIGH TEMPERATURES SHOULD REMAIN ABOVE 90 THROUGH THE PERIOD.
BRITT
&&
.AVIATION...
ISSUED AT 543 PM CDT MON JUL 30 2012
MID LEVEL CLOUDINESS ALONG WITH PATCHY LIGHT RAIN OR JUST
SPRINKLES WAS MOVING THROUGH THE TAF SITES EARLY THIS EVNG AHEAD
OF A NW FLOW SHORTWAVE OVER N CNTRL NERN MO. THIS CLOUD COVER
ALONG WITH THE SPRINKLES WILL ADVECT S-SE OF THE TAF SITES LATER
THIS EVNG. WILL INCLUDE A TEMPO GROUP FOR -RA IN ALL THE TAF SITES
EXCEPT UIN TIL 01Z TUE. SFC WINDS WILL BE LIGHT TGT AS WEAK SFC
RIDGE CENTERED OVER NERN MO SHIFTS SEWD. WEAK COLD FRONT NOW OVER
THE GREAT LAKES AND NRN PLAINS REGIONS WILL DROP SEWD THROUGH OUR
AREA ON TUE. ONLY ISOLATED SHOWERS/STORMS EXPECTED ALONG THIS
FRONT IN OUR AREA SO WILL LEAVE THE TAFS DRY FOR NOW...PLUS LITTLE
CLOUD COVER EXPECTED ON TUE. DISCOUNTED THE GFS MOS CLOUD/VSBY
GUIDANCE WHICH HAS LOW LEVEL CLOUDS AND SOME FOG LATE TGT/EARLY
TUE MRNG...PREFER THE NAM MOS GUIDANCE. N-NWLY SFC WINDS WILL
INCREASE TUE AFTN AFTER FROPA.
SPECIFICS FOR KSTL...JUST SPRINKLES FROM MID LEVEL COUD DECK
EARLY THIS EVNG. THE MID LEVEL CLOUD DECK WILL SHIFT S-SE OF STL
BY LATE TGT WITH LITTLE CLOUD COVER EXPECTED FOR THE REST OF THE
TAF PERIOD. LIGHT SFC WINDS TGT AND TUE MRNG...THEN INCREASING
FROM A NWLY DIRECTION TUE AFTN TO AROUND 10 KTS AFTER PASSAGE OF A
WEAK COLD FRONT. COULD BE ISOLATED SHOWERS/STORMS ALONG THIS FRONT
IN THE ST LOUIS METRO AREA...BUT WILL LEAVE STL TAF DRY FOR NOW
AS CONVERGENCE ALONG FRONT SHOULD BE WEAK AND ANY SIGNIFICANT
MOISTURE SHOULD BE THIN OR SHALLOW. GFS MODEL APPEARS TO HAVE TOO
MUCH SFC/BOUNDARY LAYER MOISTURE LATE TGT AND EARLY TUE MRNG
LEADING TO ITS PERIOD OF LOW LEVEL CLOUDS AND FOG IN THE GFS MOS
GUIDANCE LATE TGT AND EARLY TUE MRNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR JEFFERSON MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY FROM NOON TO 8 PM CDT TUESDAY FOR MADISON IL-
MONROE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
643 PM CDT MON JUL 30 2012
.AVIATION...
A FEW THUNDERSTORMS CAN BE EXPECTED THIS EVENING OVER THE
NEBRASKA PANHANDLE AND NORTHWEST NEBRASKA...NORTH AND WEST OF AN
ONL-IML LINE WITH THE HIGHEST PROBABILITY NORTH AND WEST OF AN
ANW-OGA LINE. THE THUNDERSTORM PROBABILITY IS LESS THAN 30 PERCENT
OVER EITHER AREA AND...FOR THE TIME BEING...WILL NOT BE INCLUDED IN
THE TERMINAL FORECASTS FOR VTN AND LBF. OTHERWISE...SOME HIGH-BASED
CUMULUS CLOUDS ARE EXPECTED ALONG WITH CIRROSTRATUS AND NO OTHER
FLIGHT RESTRICTIONS ARE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 333 PM CDT MON JUL 30 2012/
DISCUSSION...
MOISTURE AS INDICATED ON SFC OBS SHOWING DEW PTS IN THE 60S AND
SATELLITE TPW PRECIPITABLE WATER ESTIMATES NEAR 1.3 INCHES OR HIGHER
ACROSS SWRN NEB WOULD SUGGEST A REASONABLE CHANCE OF TSTMS GIVEN
THE WEAK DISTURBANCE MOVING THROUGH NRN COLO THIS AFTN. HOWEVER
THE HRRR AND THE RAP MODELS ARE VERY QUIET GENERATING LIMITED CONVECTIVE
ACTIVITY ACROSS THE HIGH PLAINS. THIS COULD BE THE RESULT OF WEAK
UPSLOPE ADVECTION...A MID LEVEL SUBSIDENCE/CAP AND WEAK STEERING
CURRENTS. MEANWHILE THE KLNX VWP INDICATES A VERY DEEP BUT WEAK
EAST WINDS EXTENDING ALL THE WAY TO 12 KFT ASL.
THE FCST THIS EVENING CALLS FOR ISOLATED STORMS GENERALLY ALONG
AND WEST OF HIGHWAY 61. WE WILL CONTINUE TO CLOSELY MONITOR THE
CONVECTION DEVELOPING IN COLO AND OBVIOUS DEEP MOISTURE PLUME
ACROSS SWRN NEB. UPSLOPE FLOW MAY INCREASE LATE THIS AFTN AND
EARLY THIS EVENING ENHANCING CONVERGENCE. THE MODERATE CU FORMING
SOUTH OF THE WEATHER OFFICE AND CIGS NEAR 5 KFT AT HOLYOKE SUGGEST
ATLEAST SOME POTENTIAL FOR ORGANIZED STORM DEVELOPMENT IF THE
DISTURBANCE ACROSS COLO CAN REACH SWRN NEB BY EARLY EVENING.
ON TUESDAY...LOW PRESSURE WILL BEGIN TRACKING THROUGH THE NRN
PLAINS WHILE HIGH PRESSURE CONTINUES ACROSS ERN NEB. THIS SHOULD
PRODUCE COOLER TEMPS SOUTH AND EAST IN THE SOUTH-SOUTHEAST WIND
AREA AND VERY WARM TEMPS ACROSS THE NW ZONES WHERE DOWN SLOPING
SOUTHWEST WINDS MAY DEVELOP. THE MOISTURE PLUME BECOMES DIFFUSE
AND LESS FOCUSED AS IT IS DRAWN NORTH IN ALL MODELS EXCEPT THE GFS
WHICH EXPLODES WEDNESDAY EVENING OVER SRN SD/NCNTL NEB AS A COLD
FRONT APPROACHES THE FCST AREA. THE FATE OF THIS MOISTURE PLUME
THE POTENTIAL FOR DESPERATELY NEEDED RAINFALL MIGHT BEST BE
HANDLED INSIDE 12 HRS. THE OTHER MODELS ARE NOT GENERATING MUCH
QPF...POSSIBLY THE RESULT OF WARM MIDLEVEL LAPSE RATES.
A WEAK AREA OF COOLER HIGH PRESSURE WILL BUILD BEHIND THE FRONT
THURSDAY AND TEMPS SHOULD SETTLE BACK IN TO THE 90S AFTER HIGHS
AROUND 100 WEDNESDAY. ALL MODELS ARE IN GOOD AGREEMENT THAT A DEEP
DISTURBANCE WILL MOVE THROUGH NRN HIGH PLAINS FRIDAY. THIS SYSTEM
SHOULD PRODUCE STRONG SOUTHWEST WINDS WITH TEMPERATURES RISING TO
OR ABOVE 100F IN MANY AREAS. A POWERFUL COLD FRONT WILL SWEEP
THROUGH FRIDAY NIGHT AND COOL TEMPS BACK INTO THE 80S FOR SATURDAY.
THE ECM HOLDS COOL HIGH PRESSURE INPLACE SUNDAY WHILE THE GFS IS
OFF TO THE RACES DEEPENING LOW PRESSURE ACROSS THE NRN HIGH PLAINS.
THE ECM IS PREFERRED FOR HIGHS IN THE LOWER 90S. BOTH MODELS ARE
SHOWING A STRONG THERMAL RIDGE ACROSS THE HIGH PLAINS MONDAY. THIS
SHOULD EASILY PRODUCE HIGHS IN THE UPPER 90S.
THE UPPER LEVEL RIDGE AND ASSOCIATED SFC HEAT LOW SHOULD REMAIN
ACROSS THE SRN HIGH PLAINS AND MID SOUTH DURING THE NEXT 7 DAYS.
THE ECM IS TRYING TO AMPLIFY THE RIDGE INTO THE CENTRAL PLAINS BY
NEXT MONDAY. RAIN CHANCES ARE GENERALLY CONFINED TO THE NORTH AND
EAST LATE FRIDAY WITH THE APPROACHING COLD FRONT. A WEAK
DISTURBANCE CROSSING ERN WY AND THE BLACK HILLS THURSDAY MAY BE
THE CATALYST FOR ISOLATED STORMS LATE IN THE DAY OR AT NIGHT
ACROSS MUCH OF THE FCST AREA. THE REST OF THE FCST...SATURDAY THROUGH
MONDAY...IS DRY.
BE AWARE THAT THE ONLY REAL HOPE FOR RAINFALL DURING THE NEXT 4
DAYS LIES IN THE FATE OF THE MOISTURE PLUME ACROSS SRN NEB THIS
AFTERNOON. THERE REMAINS A VAST AREA OF VERY DRY AIR AT THE
SURFACE AND LOWER LEVELS OF THE ATM. IN FACT THE WATER VAPOR
PAIRED WITH THE TPW PRODUCT SHOW A TREMENDOUS SURGE OF DRY AIR
FEEDING IN OFF THE PACIFIC THROUGH NEVADA...ID AND MT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1225 PM CDT SUN JUL 29 2012
.UPDATE...MADE VERY LITTLE IN THE WAY OF NOTABLE CHANGES TO THE
AFTERNOON FORECAST. LEFT AFTERNOON SHOWER/STORM CHANCES PRETTY
MUCH WHERE PREVIOUS FORECAST HAD THEM...BUT DID EXPAND THEM VERY
SLIGHTLY NORTHEASTWARD...NOW COVERING AREAS MAINLY SOUTHWEST OF AN
ELWOOD-BELOIT LINE. ALSO INCREASED POPS TO 30 PERCENT FOR THE LATE
AFTERNOON TIME FRAME ACROSS A FEW FAR SOUTHWEST COUNTIES...AS A
FEW OF THE LIGHT SHOWERS CURRENTLY POSITIONED JUST WEST OF THE
SOUTHWESTERN CWA COULD EVENTUALLY INTENSIFY/EXPAND IN COVERAGE A
BIT. THE ONGOING ACTIVITY IN SOUTHWEST NEB/NORTHWEST KS APPEARS TO
BE TIED TO A SUBTLE ZONE OF MID LEVEL CONVERGENCE EVIDENT AT
700MB...WITH A CONTINUED SLOW BUT STEADY EASTWARD PROGRESSION OF
POSSIBLE PRECIPITATION AND THE ASSOCIATED MID-HIGH LEVEL CLOUD
SHIELD EXPECTED. STILL NOT THINKING MUCH OF A SEVERE THREAT LATER THIS
AFTERNOON...BUT A FEW STRONG STORMS IN THE SOUTHWEST CERTAINLY NOT
OUT OF THE QUESTION. TEMP-WISE...THINGS ARE VERY MUCH ON TRACK
FROM PREVIOUS FORECAST...BUT DID NUDGE SOME AREAS DOWN 1-2
DEGREES BASED ON GENERAL EXPECTATION OF SLOWLY INCREASING CLOUD
COVER AS THE AFTERNOON WEARS ON. EVEN SO...MID-UPPER 90S WILL
PREVAIL IN NEB ZONES...WITH 100-104 MORE COMMON IN KS. DID
INCREASE AFTERNOON DEWPOINTS A BIT ESPECIALLY ACROSS THE SOUTHEAST
2/3 OF THE CWA...WHICH RESULTS IN HEAT INDEX VALUES STILL AT OR
NEAR ADVISORY CRITERIA OF 105 OVER KS ZONES...SO LET HEADLINE RIDE
AS-IS. NOT SURE IF NORTHWEST COUNTIES WILL SEE SOME OF THE 40S
DEWPOINTS THAT THE 12Z NAM CONTINUES TO ADVERTISE...BUT THERE IS
IN FACT A DRY POCKET OF AIR NOTED ON 17Z OBS AT BROKEN BOW AND
THEDFORD...SOME OF WHICH COULD WORK INTO PARTS OF THE NORTHWEST
CWA EVENTUALLY.
&&
.AVIATION...18Z KGRI TAF. VFR VISIBILITY/CEILING ARE FORECAST
THROUGH THE NEXT 24 HOURS...ALTHOUGH MID LEVEL CLOUDS MAINLY AT OR
ABOVE 10,000 FEET WILL GRADUALLY BE ON THE INCREASE. ITS CERTAINLY
NOT OUT OF THE QUESTION THAT A FEW THUNDERSTORMS COULD AFFECT THE
TERMINAL TONIGHT...BUT WITH BETTER CHANCES FOCUSING AT LEAST 50
MILES TO THE SOUTHWEST...WILL OMIT ALL MENTION OF PRECIPITATION IN
THE TAF FOR NOW AND LET LATER SHIFTS INTRODUCE IF CONFIDENCE
INCREASES. AS FOR VISIBILITY...LIGHT EASTERLY BREEZES COULD RESULT
IN SOME LIGHT HAZE OVERNIGHT...BUT NOT ANTICIPATING ANYTHING BELOW
7SM AT THIS TIME. SPEAKING OF BREEZES...RELATIVELY LITTLE CHANGE IS
EXPECTED OVER THE NEXT 24 HOURS...WITH SUSTAINED SPEEDS AVERAGING
AT OR BELOW 10KT...AND DIRECTION LARGELY STAYING WITHIN 30
DEGREES EITHER SIDE OF DUE EASTERLY.
&&
.PREV DISCUSSION... /ISSUED 430 AM CDT SUN JUL 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERNS LIE WITH PRECIPITATION CHANCES...AND TEMPERATURES.
BEEN LITTLE OVERALL CHANGE IN THE UPPER LEVEL PATTERN ACROSS THE
REGION...WITH SATELLITE AND PROFILER DATA SHOWING IT REMAINING
DOMINATED BY UPPER LEVEL HIGH PRESSURE/RIDGING CENTERED JUST WEST
OF THE CWA. THIS LEAVES NORTHWESTERLY FLOW IN PLACE...WITH A
DISTURBANCE SHIFTING SOUTHEAST THIS MORNING...RIDING AROUND THE
EDGE OF THE RIDGE. CONTINUING TO SEE A FEW SHOWERS/THUNDERSTORMS
LINGER IN FAR SWRN PORTIONS OF THE CWA EARLY THIS MORNING
RESULTING FROM THIS DISTURBANCE...BUT EXPECT THEM TO EXIT THE CWA
OVER THE NEXT COUPLE HOURS. SEEING A WEAK SURFACE PATTERN IN PLACE
OVER THE CWA...BRINGING LIGHT AND VARIABLE WINDS EARLY THIS
MORNING...THOUGH A WEAK BOUNDARY IS IN PLACE JUST SOUTH OF THE
CWA.
FOR TODAY AND TONIGHT...NO SIGNIFICANT CHANGES WERE MADE TO THE
INHERITED FORECAST. KEPT THE FIRST HALF THE DRY QUIET...WITH
THUNDERSTORM CHANCES RETURNING DURING THE LATE AFTERNOON AND INTO
THE OVERNIGHT HOURS. MODELS NOT IN TOO BAD OF AGREEMENT SHOWING
THE SURFACE BOUNDARY REMAINING NEAR/JUST SOUTH OF THE CWA
THROUGH THE DAYTIME HOURS...AND AS ANOTHER WEAK UPPER LEVEL
DISTURBANCE LOOKS TO ROUND THE EDGE OF THE RIDGE AND MOVE INTO THE
REGION...THUNDERSTORM CHANCES WILL INCREASE. TIMING/OVERALL
COVERAGE REMAINS UNCERTAIN...LITTLE MORE DIFFERENCE BETWEEN
MODELS...NAM CONTINUES TO SHOW AN EARLIER ONSET OF ACTIVITY...VS
OTHERS LIKE THE 06Z HRRR WHICH IS QUIET THRU 21Z...AND THE 00Z 4KM
WRF WHICH SHOWS VERY LITTLE GOING ON AT ALL. BECAUSE OF THESE
DIFFERENCES KEPT POPS THOUGH TONIGHT LOW. COULD SEE A FEW
THUNDERSTORMS ON THE STRONG SIDE...BUT WITH DEEPER LAYER SHEAR
AGAIN ON THE WEAKER SIDE...CHANCES FOR SEVERE WEATHER IS LOW.
AS FAR AS TEMPERATURES GO...WITH THE MORE EASTERLY COMPONENT TO
THE WINDS /ESP ACROSS SC NEB/ STILL EXPECTED...AGAIN MADE FEW
CHANGES. MID/UPPER 90S ARE IN PLACE ACROSS THE NORTH...WITH LOWER
100S POSSIBLE ACROSS NC KS. ENDED UP ISSUING A HEAT ADV FOR NC KS
THIS AFTERNOON...WHERE POTENTIAL FOR HEAT INDEX VALUES NEAR 105
LIES...WITH TEMPS NEAR/JUST ABOVE 100 POSSIBLE AND HIGHER
DEWPOINTS EXPECTED AS THAT AREA SITS NEAR/JUST NORTH OF THE SFC
FRONT. CERTAINLY NOT A SLAM DUNK ADVISORY...A COUPLE OF THINGS
COULD POTENTIALLY MESS UP THE FORECAST HIGHS IN NC KS...SUCH AS
EVEN HIGHER DEWPOINTS THAN CURRENTLY FORECAST /SOME DATA SHOWS
DPTS CLOSER TO THE MID TO UPPER 60S VS THE NEAR 60
FORECAST/...AND/OR HIGHER CLOUD COVER THAN WHAT IS CURRENTLY
FORECAST DURING THE PEAK OF THE AFTERNOON. DECIDED TO GO WITH THE
AREA THAT HAD THE BEST POTENTIAL TO MEET CRITERIA...ALSO THINKING
THE AFFECTS OF ANY THUNDERSTORM DEVELOPMENT WOULD HOLD OFF UNTIL
LATER IN THE AFTERNOON.
GETTING INTO MONDAY AND TUESDAY...AGAIN SEE LITTLE CHANGE IN THE
OVERALL UPPER LEVEL PATTERN...AND CONFIDENCE IN PRECIPITATION
CHANCES REMAINS ON THE LOW SIDE. THE CWA REMAINS UNDER THE
INFLUENCE OF THAT UPPER LEVEL RIDGE...BUT IT DOESNT EXTEND FAR
ENOUGH NORTH TO KEEP US OUT OF THE WAY OF ANY WEAK DISTURBANCE
MAKING THEIR WAY AROUND THE EDGE OF THE RIDGE. ALONG WITH THE
POTENTIAL FOR DISTURBANCES MOVING THROUGH...MODELS NOT IN TOO BAD
OF AGREEMENT SHOWING THIS LINGERING SURFACE BOUNDARY GENERALLY
NEAR/SOUTH OF THE NEB/KS STATE LINE. THOUGH THERE ARE POPS IN
PLACE THROUGH TUESDAY NIGHT...CERTAINLY DONT WANT TO GIVE OFF THE
IMPRESSION THAT THERE ARE GOOD/WIDESPREAD POSSIBILITIES THE ENTIRE
TIME. THE ISSUE IS THAT AT EVEN THIS POINT...JUST A DAY OR TWO
OUT...THERE IS STILL ENOUGH UNCERTAINTY WITH THE TIMING/PLACEMENT
OF THESE DISTURBANCES AND ASSOCIATED PRECIP CHANCES THAT NAILING
DOWN MORE SPECIFIC DETAILS...INCREASING OR REMOVING POPS FOR
PARTICULAR LOCATIONS...IS DIFFICULT...BUT AT LEAST THE CHANCES ARE
THERE. FORECAST HIGHS FOR MONDAY REMAIN GENERALLY IN THE LOWER/MID
90S...WITH TUESDAY IN THE MID/UPPER 90S.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
CONCERNS FOR THE TERM PERIOD AGAIN FOCUS ON THUNDERSTORM CHANCES
AND NUMEROUS SHORT WAVE PERTURBATIONS AROUND THE UPPER LEVEL
RIDGE. OTHERWISE NO CHANGES WERE MADE TO THE PREVIOUS FORECAST.
BEGINNING THE LONG TERM PERIOD...THE UPPER LEVEL RIDGE REMAINS
STATIONARY ACROSS PORTIONS OF TEXAS AND OKLAHOMA...FLANKED BY TWO
UPPER LEVEL TROUGHS ON EITHER COAST. THROUGHOUT THE PERIOD...THE
RIDGE SLOWLY BEGINS TO BREAK DOWN AS THE WESTERNMOST TROUGH
CONTINUES TO SHIFT EASTWARD ACROSS CANADA. AS SUCH...THE PEAK OF
THE RIDGE FLATTENS OUT ENOUGH THAT THE PLAINS REMAIN IN PERFECT
POSITION FOR ANY UPPER LEVEL SHORT WAVE THAT PASSES BY. ALTHOUGH
THERE REMAINS MANY DISCREPANCIES ON BOTH UPPER LEVEL FEATURES AND
SURFACE FEATURES AMONG THE LONG TERM MODELS...IT IS BECOMING MORE
AND MORE APPARENT AND SUGGESTED BY THE ALL BLEND MODELS THAT THERE
IS A POSSIBILITY OF AT LEAST SOME PRECIPITATION IN THE LONG TERM.
WHILE IT REMAINS QUITE TOUGH TO PINPOINT EXACTLY WHEN AND WHERE
THESE SHOWERS WILL OCCUR...WAS NOT CONFIDENT ENOUGH TO PULL ALL
POPS COMPLETELY OR LEAVE SLIGHT CHANCES IN EVERY PERIOD AS
SUGGESTED BY ALL BLENDS. PER NEIGHBOR COLLABORATION AND MODELS
INDICATIONS OF THE PRESENCE OF SHORT WAVES AND SURFACE BOUNDARIES
ACROSS THE REGION...CONTINUED WITH SLIGHT CHANCES BOTH WEDNESDAY
AFTERNOON...THURSDAY AND FRIDAY.
REGARDING TEMPERATURES IN THE LONG TERM...EXPECTING WARM
TEMPERATURES TO LAST THROUGH THE PERIOD...ALTHOUGH NOT QUITE HAS
HOT AS PREVIOUS WEEKS...CONTINUED WITH 90S TO NEAR 100 ACROSS
THE AREA. CLOUD COVER AND PRECIPITATION CHANCES COULD CERTAINLY
COME INTO QUESTION AND REDUCE HIGHS JUST SLIGHTLY. ALSO CONFIDENCE
REMAINS LOW FOR TEMPERATURES ON SATURDAY. THE GFS SOLUTION AND THE
ECWMF SOLUTION REMAIN COMPLETELY OPPOSITE EACH OTHER....WITH THE
GFS DRAGGING A COLD FRONT THROUGH THE REGION AND THE ECMWF
SUGGESTS A HIGH OVER THE AREA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ005>007-017>019.
&&
$$
AVIATION/UPDATE...PFANNKUCH
SHORT TERM...ADO
LONG TERM...SALTZMAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 AM CDT SUN JUL 29 2012
.AVIATION...12Z KGRI TAF. A SURFACE BOUNDARY WILL LINGER ACROSS
THE FORECAST AREA THROUGHOUT THE TAF PERIOD. WHILE VFR CONDITIONS
ARE EXPECTED THROUGHOUT PERIOD...A FEW WEATHER CONCERNS SHOULD BE
MONITORED. LIGHT AND VARIABLE WINDS THIS MORNING WILL TRANSITION
TO THE NORTHEAST BEFORE TURNING TO THE EAST THIS AFTERNOON AND
EVENING. THERE REMAINS A CHANCE FOR ISOLATED SHOWERS AND
THUNDERSTORMS NEAR THE SURFACE BOUNDARY THIS AFTERNOON AND DURING
THE OVERNIGHT HOURS. WHILE THESE SHOWERS REMAIN ISOLATED IN NATURE
AND TOWARDS THE END OF THE PERIOD...WILL LET OTHER SHIFTS CONTINUE
TO MONITOR AND ADD AS NEEDED. ALONG THE BOUNDARY INCREASED CLOUDS
WILL ALSO CONTINUE THIS AFTERNOON WITH A OVERCAST MID LEVEL DECK
EXPECTED OVERNIGHT SHOULD THUNDERSTORMS BE AROUND.
&&
.PREV DISCUSSION... /ISSUED 430 AM CDT SUN JUL 29 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERNS LIE WITH PRECIPITATION CHANCES...AND TEMPERATURES.
BEEN LITTLE OVERALL CHANGE IN THE UPPER LEVEL PATTERN ACROSS THE
REGION...WITH SATELLITE AND PROFILER DATA SHOWING IT REMAINING
DOMINATED BY UPPER LEVEL HIGH PRESSURE/RIDGING CENTERED JUST WEST
OF THE CWA. THIS LEAVES NORTHWESTERLY FLOW IN PLACE...WITH A
DISTURBANCE SHIFTING SOUTHEAST THIS MORNING...RIDING AROUND THE
EDGE OF THE RIDGE. CONTINUING TO SEE A FEW SHOWERS/THUNDERSTORMS
LINGER IN FAR SWRN PORTIONS OF THE CWA EARLY THIS MORNING
RESULTING FROM THIS DISTURBANCE...BUT EXPECT THEM TO EXIT THE CWA
OVER THE NEXT COUPLE HOURS. SEEING A WEAK SURFACE PATTERN IN PLACE
OVER THE CWA...BRINGING LIGHT AND VARIABLE WINDS EARLY THIS
MORNING...THOUGH A WEAK BOUNDARY IS IN PLACE JUST SOUTH OF THE
CWA.
FOR TODAY AND TONIGHT...NO SIGNIFICANT CHANGES WERE MADE TO THE
INHERITED FORECAST. KEPT THE FIRST HALF THE DRY QUIET...WITH
THUNDERSTORM CHANCES RETURNING DURING THE LATE AFTERNOON AND INTO
THE OVERNIGHT HOURS. MODELS NOT IN TOO BAD OF AGREEMENT SHOWING
THE SURFACE BOUNDARY REMAINING NEAR/JUST SOUTH OF THE CWA
THROUGH THE DAYTIME HOURS...AND AS ANOTHER WEAK UPPER LEVEL
DISTURBANCE LOOKS TO ROUND THE EDGE OF THE RIDGE AND MOVE INTO THE
REGION...THUNDERSTORM CHANCES WILL INCREASE. TIMING/OVERALL
COVERAGE REMAINS UNCERTAIN...LITTLE MORE DIFFERENCE BETWEEN
MODELS...NAM CONTINUES TO SHOW AN EARLIER ONSET OF ACTIVITY...VS
OTHERS LIKE THE 06Z HRRR WHICH IS QUIET THRU 21Z...AND THE 00Z 4KM
WRF WHICH SHOWS VERY LITTLE GOING ON AT ALL. BECAUSE OF THESE
DIFFERENCES KEPT POPS THOUGH TONIGHT LOW. COULD SEE A FEW
THUNDERSTORMS ON THE STRONG SIDE...BUT WITH DEEPER LAYER SHEAR
AGAIN ON THE WEAKER SIDE...CHANCES FOR SEVERE WEATHER IS LOW.
AS FAR AS TEMPERATURES GO...WITH THE MORE EASTERLY COMPONENT TO
THE WINDS /ESP ACROSS SC NEB/ STILL EXPECTED...AGAIN MADE FEW
CHANGES. MID/UPPER 90S ARE IN PLACE ACROSS THE NORTH...WITH LOWER
100S POSSIBLE ACROSS NC KS. ENDED UP ISSUING A HEAT ADV FOR NC KS
THIS AFTERNOON...WHERE POTENTIAL FOR HEAT INDEX VALUES NEAR 105
LIES...WITH TEMPS NEAR/JUST ABOVE 100 POSSIBLE AND HIGHER
DEWPOINTS EXPECTED AS THAT AREA SITS NEAR/JUST NORTH OF THE SFC
FRONT. CERTAINLY NOT A SLAM DUNK ADVISORY...A COUPLE OF THINGS
COULD POTENTIALLY MESS UP THE FORECAST HIGHS IN NC KS...SUCH AS
EVEN HIGHER DEWPOINTS THAN CURRENTLY FORECAST /SOME DATA SHOWS
DPTS CLOSER TO THE MID TO UPPER 60S VS THE NEAR 60
FORECAST/...AND/OR HIGHER CLOUD COVER THAN WHAT IS CURRENTLY
FORECAST DURING THE PEAK OF THE AFTERNOON. DECIDED TO GO WITH THE
AREA THAT HAD THE BEST POTENTIAL TO MEET CRITERIA...ALSO THINKING
THE AFFECTS OF ANY THUNDERSTORM DEVELOPMENT WOULD HOLD OFF UNTIL
LATER IN THE AFTERNOON.
GETTING INTO MONDAY AND TUESDAY...AGAIN SEE LITTLE CHANGE IN THE
OVERALL UPPER LEVEL PATTERN...AND CONFIDENCE IN PRECIPITATION
CHANCES REMAINS ON THE LOW SIDE. THE CWA REMAINS UNDER THE
INFLUENCE OF THAT UPPER LEVEL RIDGE...BUT IT DOESNT EXTEND FAR
ENOUGH NORTH TO KEEP US OUT OF THE WAY OF ANY WEAK DISTURBANCE
MAKING THEIR WAY AROUND THE EDGE OF THE RIDGE. ALONG WITH THE
POTENTIAL FOR DISTURBANCES MOVING THROUGH...MODELS NOT IN TOO BAD
OF AGREEMENT SHOWING THIS LINGERING SURFACE BOUNDARY GENERALLY
NEAR/SOUTH OF THE NEB/KS STATE LINE. THOUGH THERE ARE POPS IN
PLACE THROUGH TUESDAY NIGHT...CERTAINLY DONT WANT TO GIVE OFF THE
IMPRESSION THAT THERE ARE GOOD/WIDESPREAD POSSIBILITIES THE ENTIRE
TIME. THE ISSUE IS THAT AT EVEN THIS POINT...JUST A DAY OR TWO
OUT...THERE IS STILL ENOUGH UNCERTAINTY WITH THE TIMING/PLACEMENT
OF THESE DISTURBANCES AND ASSOCIATED PRECIP CHANCES THAT NAILING
DOWN MORE SPECIFIC DETAILS...INCREASING OR REMOVING POPS FOR
PARTICULAR LOCATIONS...IS DIFFICULT...BUT AT LEAST THE CHANCES ARE
THERE. FORECAST HIGHS FOR MONDAY REMAIN GENERALLY IN THE LOWER/MID
90S...WITH TUESDAY IN THE MID/UPPER 90S.
LONG TERM...WEDNESDAY THROUGH SATURDAY.
CONCERNS FOR THE TERM PERIOD AGAIN FOCUS ON THUNDERSTORM CHANCES
AND NUMEROUS SHORT WAVE PERTURBATIONS AROUND THE UPPER LEVEL
RIDGE. OTHERWISE NO CHANGES WERE MADE TO THE PREVIOUS FORECAST.
BEGINNING THE LONG TERM PERIOD...THE UPPER LEVEL RIDGE REMAINS
STATIONARY ACROSS PORTIONS OF TEXAS AND OKLAHOMA...FLANKED BY TWO
UPPER LEVEL TROUGHS ON EITHER COAST. THROUGHOUT THE PERIOD...THE
RIDGE SLOWLY BEGINS TO BREAK DOWN AS THE WESTERNMOST TROUGH
CONTINUES TO SHIFT EASTWARD ACROSS CANADA. AS SUCH...THE PEAK OF
THE RIDGE FLATTENS OUT ENOUGH THAT THE PLAINS REMAIN IN PERFECT
POSITION FOR ANY UPPER LEVEL SHORT WAVE THAT PASSES BY. ALTHOUGH
THERE REMAINS MANY DISCREPANCIES ON BOTH UPPER LEVEL FEATURES AND
SURFACE FEATURES AMONG THE LONG TERM MODELS...IT IS BECOMING MORE
AND MORE APPARENT AND SUGGESTED BY THE ALL BLEND MODELS THAT THERE
IS A POSSIBILITY OF AT LEAST SOME PRECIPITATION IN THE LONG TERM.
WHILE IT REMAINS QUITE TOUGH TO PINPOINT EXACTLY WHEN AND WHERE
THESE SHOWERS WILL OCCUR...WAS NOT CONFIDENT ENOUGH TO PULL ALL
POPS COMPLETELY OR LEAVE SLIGHT CHANCES IN EVERY PERIOD AS
SUGGESTED BY ALL BLENDS. PER NEIGHBOR COLLABORATION AND MODELS
INDICATIONS OF THE PRESENCE OF SHORT WAVES AND SURFACE BOUNDARIES
ACROSS THE REGION...CONTINUED WITH SLIGHT CHANCES BOTH WEDNESDAY
AFTERNOON...THURSDAY AND FRIDAY.
REGARDING TEMPERATURES IN THE LONG TERM...EXPECTING WARM
TEMPERATURES TO LAST THROUGH THE PERIOD...ALTHOUGH NOT QUITE HAS
HOT AS PREVIOUS WEEKS...CONTINUED WITH 90S TO NEAR 100 ACROSS
THE AREA. CLOUD COVER AND PRECIPITATION CHANCES COULD CERTAINLY
COME INTO QUESTION AND REDUCE HIGHS JUST SLIGHTLY. ALSO CONFIDENCE
REMAINS LOW FOR TEMPERATURES ON SATURDAY. THE GFS SOLUTION AND THE
ECWMF SOLUTION REMAIN COMPLETELY OPPOSITE EACH OTHER....WITH THE
GFS DRAGGING A COLD FRONT THROUGH THE REGION AND THE ECMWF
SUGGESTS A HIGH OVER THE AREA.
AVIATION...06Z KGRI TAF. AS SURFACE LOW PRESSURE CONTINUES TO
SPIN ACROSS WESTERN KANSAS...SURFACE HIGH PRESSURE WILL GRAZE
NORTHERN PORTIONS OF NEBRASKA TODAY. AS A RESULT...LIGHT AND
VARIABLE WINDS WILL GRADUALLY SHIFT TO THE NORTHEAST THIS MORNING
BEFORE TURNING EASTWARD BY THE END OF THE PERIOD. WHILE A FEW
SCATTERED TO EVEN BROKEN CLOUD DECK WILL APPEAR AT TIMES
THROUGHOUT THE PERIOD...EXPECTING VFR CONDITIONS TO CONTINUE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
FOR KSZ005>007-017>019.
&&
$$
SHORT...ADO
LONG/AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
430 AM CDT SUN JUL 29 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT. PRIMARY FORECAST
CONCERNS LIE WITH PRECIPITATION CHANCES...AND TEMPERATURES.
BEEN LITTLE OVERALL CHANGE IN THE UPPER LEVEL PATTERN ACROSS THE
REGION...WITH SATELLITE AND PROFILER DATA SHOWING IT REMAINING
DOMINATED BY UPPER LEVEL HIGH PRESSURE/RIDGING CENTERED JUST WEST
OF THE CWA. THIS LEAVES NORTHWESTERLY FLOW IN PLACE...WITH A
DISTURBANCE SHIFTING SOUTHEAST THIS MORNING...RIDING AROUND THE
EDGE OF THE RIDGE. CONTINUING TO SEE A FEW SHOWERS/THUNDERSTORMS
LINGER IN FAR SWRN PORTIONS OF THE CWA EARLY THIS MORNING
RESULTING FROM THIS DISTURBANCE...BUT EXPECT THEM TO EXIT THE CWA
OVER THE NEXT COUPLE HOURS. SEEING A WEAK SURFACE PATTERN IN PLACE
OVER THE CWA...BRINGING LIGHT AND VARIABLE WINDS EARLY THIS
MORNING...THOUGH A WEAK BOUNDARY IS IN PLACE JUST SOUTH OF THE
CWA.
FOR TODAY AND TONIGHT...NO SIGNIFICANT CHANGES WERE MADE TO THE
INHERITED FORECAST. KEPT THE FIRST HALF THE DRY QUIET...WITH
THUNDERSTORM CHANCES RETURNING DURING THE LATE AFTERNOON AND INTO
THE OVERNIGHT HOURS. MODELS NOT IN TOO BAD OF AGREEMENT SHOWING
THE SURFACE BOUNDARY REMAINING NEAR/JUST SOUTH OF THE CWA
THROUGH THE DAYTIME HOURS...AND AS ANOTHER WEAK UPPER LEVEL
DISTURBANCE LOOKS TO ROUND THE EDGE OF THE RIDGE AND MOVE INTO THE
REGION...THUNDERSTORM CHANCES WILL INCREASE. TIMING/OVERALL
COVERAGE REMAINS UNCERTAIN...LITTLE MORE DIFFERENCE BETWEEN
MODELS...NAM CONTINUES TO SHOW AN EARLIER ONSET OF ACTIVITY...VS
OTHERS LIKE THE 06Z HRRR WHICH IS QUIET THRU 21Z...AND THE 00Z 4KM
WRF WHICH SHOWS VERY LITTLE GOING ON AT ALL. BECAUSE OF THESE
DIFFERENCES KEPT POPS THOUGH TONIGHT LOW. COULD SEE A FEW
THUNDERSTORMS ON THE STRONG SIDE...BUT WITH DEEPER LAYER SHEAR
AGAIN ON THE WEAKER SIDE...CHANCES FOR SEVERE WEATHER IS LOW.
AS FAR AS TEMPERATURES GO...WITH THE MORE EASTERLY COMPONENT TO
THE WINDS /ESP ACROSS SC NEB/ STILL EXPECTED...AGAIN MADE FEW
CHANGES. MID/UPPER 90S ARE IN PLACE ACROSS THE NORTH...WITH LOWER
100S POSSIBLE ACROSS NC KS. ENDED UP ISSUING A HEAT ADV FOR NC KS
THIS AFTERNOON...WHERE POTENTIAL FOR HEAT INDEX VALUES NEAR 105
LIES...WITH TEMPS NEAR/JUST ABOVE 100 POSSIBLE AND HIGHER
DEWPOINTS EXPECTED AS THAT AREA SITS NEAR/JUST NORTH OF THE SFC
FRONT. CERTAINLY NOT A SLAM DUNK ADVISORY...A COUPLE OF THINGS
COULD POTENTIALLY MESS UP THE FORECAST HIGHS IN NC KS...SUCH AS
EVEN HIGHER DEWPOINTS THAN CURRENTLY FORECAST /SOME DATA SHOWS
DPTS CLOSER TO THE MID TO UPPER 60S VS THE NEAR 60
FORECAST/...AND/OR HIGHER CLOUD COVER THAN WHAT IS CURRENTLY
FORECAST DURING THE PEAK OF THE AFTERNOON. DECIDED TO GO WITH THE
AREA THAT HAD THE BEST POTENTIAL TO MEET CRITERIA...ALSO THINKING
THE AFFECTS OF ANY THUNDERSTORM DEVELOPMENT WOULD HOLD OFF UNTIL
LATER IN THE AFTERNOON.
GETTING INTO MONDAY AND TUESDAY...AGAIN SEE LITTLE CHANGE IN THE
OVERALL UPPER LEVEL PATTERN...AND CONFIDENCE IN PRECIPITATION
CHANCES REMAINS ON THE LOW SIDE. THE CWA REMAINS UNDER THE
INFLUENCE OF THAT UPPER LEVEL RIDGE...BUT IT DOESNT EXTEND FAR
ENOUGH NORTH TO KEEP US OUT OF THE WAY OF ANY WEAK DISTURBANCE
MAKING THEIR WAY AROUND THE EDGE OF THE RIDGE. ALONG WITH THE
POTENTIAL FOR DISTURBANCES MOVING THROUGH...MODELS NOT IN TOO BAD
OF AGREEMENT SHOWING THIS LINGERING SURFACE BOUNDARY GENERALLY
NEAR/SOUTH OF THE NEB/KS STATE LINE. THOUGH THERE ARE POPS IN
PLACE THROUGH TUESDAY NIGHT...CERTAINLY DONT WANT TO GIVE OFF THE
IMPRESSION THAT THERE ARE GOOD/WIDESPREAD POSSIBILITIES THE ENTIRE
TIME. THE ISSUE IS THAT AT EVEN THIS POINT...JUST A DAY OR TWO
OUT...THERE IS STILL ENOUGH UNCERTAINTY WITH THE TIMING/PLACEMENT
OF THESE DISTURBANCES AND ASSOCIATED PRECIP CHANCES THAT NAILING
DOWN MORE SPECIFIC DETAILS...INCREASING OR REMOVING POPS FOR
PARTICULAR LOCATIONS...IS DIFFICULT...BUT AT LEAST THE CHANCES ARE
THERE. FORECAST HIGHS FOR MONDAY REMAIN GENERALLY IN THE LOWER/MID
90S...WITH TUESDAY IN THE MID/UPPER 90S.
.LONG TERM...WEDNESDAY THROUGH SATURDAY.
CONCERNS FOR THE TERM PERIOD AGAIN FOCUS ON THUNDERSTORM CHANCES
AND NUMEROUS SHORT WAVE PERTURBATIONS AROUND THE UPPER LEVEL
RIDGE. OTHERWISE NO CHANGES WERE MADE TO THE PREVIOUS FORECAST.
BEGINNING THE LONG TERM PERIOD...THE UPPER LEVEL RIDGE REMAINS
STATIONARY ACROSS PORTIONS OF TEXAS AND OKLAHOMA...FLANKED BY TWO
UPPER LEVEL TROUGHS ON EITHER COAST. THROUGHOUT THE PERIOD...THE
RIDGE SLOWLY BEGINS TO BREAK DOWN AS THE WESTERNMOST TROUGH
CONTINUES TO SHIFT EASTWARD ACROSS CANADA. AS SUCH...THE PEAK OF
THE RIDGE FLATTENS OUT ENOUGH THAT THE PLAINS REMAIN IN PERFECT
POSITION FOR ANY UPPER LEVEL SHORT WAVE THAT PASSES BY. ALTHOUGH
THERE REMAINS MANY DISCREPANCIES ON BOTH UPPER LEVEL FEATURES AND
SURFACE FEATURES AMONG THE LONG TERM MODELS...IT IS BECOMING MORE
AND MORE APPARENT AND SUGGESTED BY THE ALL BLEND MODELS THAT THERE
IS A POSSIBILITY OF AT LEAST SOME PRECIPITATION IN THE LONG TERM.
WHILE IT REMAINS QUITE TOUGH TO PINPOINT EXACTLY WHEN AND WHERE
THESE SHOWERS WILL OCCUR...WAS NOT CONFIDENT ENOUGH TO PULL ALL
POPS COMPLETELY OR LEAVE SLIGHT CHANCES IN EVERY PERIOD AS
SUGGESTED BY ALL BLENDS. PER NEIGHBOR COLLABORATION AND MODELS
INDICATIONS OF THE PRESENCE OF SHORT WAVES AND SURFACE BOUNDARIES
ACROSS THE REGION...CONTINUED WITH SLIGHT CHANCES BOTH WEDNESDAY
AFTERNOON...THURSDAY AND FRIDAY.
REGARDING TEMPERATURES IN THE LONG TERM...EXPECTING WARM
TEMPERATURES TO LAST THROUGH THE PERIOD...ALTHOUGH NOT QUITE HAS
HOT AS PREVIOUS WEEKS...CONTINUED WITH 90S TO NEAR 100 ACROSS
THE AREA. CLOUD COVER AND PRECIPITATION CHANCES COULD CERTAINLY
COME INTO QUESTION AND REDUCE HIGHS JUST SLIGHTLY. ALSO CONFIDENCE
REMAINS LOW FOR TEMPERATURES ON SATURDAY. THE GFS SOLUTION AND THE
ECWMF SOLUTION REMAIN COMPLETELY OPPOSITE EACH OTHER....WITH THE
GFS DRAGGING A COLD FRONT THROUGH THE REGION AND THE ECMWF
SUGGESTS A HIGH OVER THE AREA.
&&
.AVIATION...06Z KGRI TAF. AS SURFACE LOW PRESSURE CONTINUES TO
SPIN ACROSS WESTERN KANSAS...SURFACE HIGH PRESSURE WILL GRAZE
NORTHERN PORTIONS OF NEBRASKA TODAY. AS A RESULT...LIGHT AND
VARIABLE WINDS WILL GRADUALLY SHIFT TO THE NORTHEAST THIS MORNING
BEFORE TURNING EASTWARD BY THE END OF THE PERIOD. WHILE A FEW
SCATTERED TO EVEN BROKEN CLOUD DECK WILL APPEAR AT TIMES
THROUGHOUT THE PERIOD...EXPECTING VFR CONDITIONS TO CONTINUE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 8 PM CDT THIS EVENING
FOR KSZ005>007-017>019.
&&
$$
SHORT...ADO
LONG/AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1218 AM CDT SUN JUL 29 2012
.AVIATION...06Z KGRI TAF. AS SURFACE LOW PRESSURE CONTINUES TO
SPIN ACROSS WESTERN KANSAS...SURFACE HIGH PRESSURE WILL GRAZE
NORTHERN PORTIONS OF NEBRASKA TODAY. AS A RESULT...LIGHT AND
VARIABLE WINDS WILL GRADUALLY SHIFT TO THE NORTHEAST THIS MORNING
BEFORE TURNING EASTWARD BY THE END OF THE PERIOD. WHILE A FEW
SCATTERED TO EVEN BROKEN CLOUD DECK WILL APPEAR AT TIMES
THROUGHOUT THE PERIOD...EXPECTING VFR CONDITIONS TO CONTINUE.
&&
.PREV DISCUSSION... /ISSUED 656 PM CDT SAT JUL 28 2012/
UPDATE...IT WAS A DIFFICULT CALL ON WHETHER TO GO WITH A SEVERE
THUNDERSTORM WATCH THIS EVENING AND IT WAS DISCUSSED AT LENGTH
WITH SEVERAL SURROUNDING OFFICES. CONVECTION THUS FAR HAS BEEN
RATHER MARGINAL ALTHOUGH A FEW STORMS HAVE SHOWN RECENT SIGNS OF
STRENGTHENING AND THE ENVIRONMENT IS MORE SUPPORTIVE THAN WE HAVE
SEEN FOR SOME TIME WITH DEEP LAYER SHEAR VALUES OF OVER 50 KTS
ACROSS OUR NORTH. THESE ARE VERY GOOD SHEAR VALUES FOR THIS TIME
OF YEAR. ACROSS OUR SOUTH THE SHEAR IS MUCH WEAKER AT AROUND 20
KTS...BUT THE STEEP LAPSE RATES AND INVERTED V SOUNDINGS ARE
INDICATIVE OF AN ENHANCED WIND THREAT ACROSS KANSAS ZONES AND
PORTIONS OF SOUTHERN NEBRASKA. THERE IS ALSO PLENTY OF CAPE WITH
MLCAPE VALUES RANGING FROM 1500 J/KG ACROSS KANSAS TO 2500 J/KG
OVER NEBRASKA. ULTIMATELY IT WAS DECIDED TO GO WITH A SEVERE
THUNDERSTORM WATCH THROUGH 1 AM.
AVIATION...00Z KGRI TAF. THUNDERSTORMS HAVE DEVELOPED ACROSS
SOUTH CENTRAL NEBRASKA AND COULD MOVE INTO THE KGRI VICINITY.
STILL TOO EARLY TO TELL IF ONE WILL DIRECTLY HIT KGRI OR NOT. SO
FAR THE ACTIVITY IS FAIRLY ISOLATED AN THUS HAVE ONLY INCLUDED
VICINITY WORDING IN THE TAF. THE WIND WILL BE LIGHT OUTSIDE OF
THUNDERSTORMS...BUT COULD BE VERY GUSTY SHOULD A THUNDERSTORM NEAR
THE AREA. THUNDERSTORM ACTIVITY WILL DIMINISH BY LATE EVENING.
PREV DISCUSSION... /ISSUED 412 PM CDT SAT JUL 28 2012/
SHORT TERM...THROUGH LATE SUNDAY AFTERNOON. THE MOST IMPORTANT
ISSUE OVER THE NEXT 24 HOURS IS MONITORING FOR STRONG TO SEVERE
CONVECTION MAINLY THROUGH MIDNIGHT TONIGHT...WITH SECONDARY
CONCERNS CONSISTING OF NEAR HEAT ADVISORY CONDITIONS MAINLY IN
NORTH CENTRAL KS ZONES SUNDAY AFTERNOON...AND ALSO VERY-NEAR
CRITICAL FIRE WEATHER CONDITIONS THROUGH EARLY THIS EVENING IN
SOUTHWEST ZONES.
19Z OBJECTIVE SURFACE ANALYSIS INDICATES WHAT ESSENTIALLY AMOUNTS
TO A TRIPLE POINT ACROSS SOUTHWEST PORTIONS OF THE CWA...AS A
WELL-DEFINED NORTHWEST-SOUTHEAST ORIENTED WARM FRONT CONTINUES
SURGING NORTHEAST INTO THE CWA...WHILE A WEAK SURFACE TROUGH
EXTENDS FROM THE FURNAS COUNTY AREA NORTHWARD INTO NORTH CENTRAL
NEB. AS EXPECTED...TEMPERATURES HAVE SOARED IN THE SOUTHWESTERLY
FLOW IN THE WAKE OF THE WARM FRONT...WITH A SEASONABLY IMPRESSIVE
MID AFTERNOON TEMPERATURE GRADIENT RANGING FROM THE UPPER 80S-LOW
90S IN NORTH/NORTHEAST ZONES...TO 102-108 IN SEVERAL SOUTHWEST
COUNTIES. WIND DIRECTION IS ALSO SHOWING A RATHER SHARP VARIANCE
ACROSS THE WARM FRONT...TRANSITIONING FROM SOUTHEASTERLY TO
SOUTHWESTERLY AS THE WARM FRONT PASSES...ALONG WITH A NOTICEABLE
DECREASE IN DEWPOINTS. VISIBLE SATELLITE IMAGERY IS SHOWING QUITE
A BIT OF MID LEVEL CLOUD COVER INCREASING OVER THE CWA FROM THE
NORTHWEST...WHILE ALONG THE ADVANCING WARM FRONT AND TRIPLE POINT
AREA...THUS FAR WEAK ISOLATED/SCATTERED SHOWERS/STORMS ARE
DEVELOPING ON THE LEADING EDGE OF A SCATTERED CUMULUS
FIELD...WITH THE BOUNDARY LAYER CUMULUS AREA CLOSELY TIED TO THE
EDGE OF A NORTHEASTWARD ADVANCING PLUME OF STEEP LOW LEVEL LAPSE
RATES. WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA REVEALS THE
CENTER OF THE PRIMARY MID-UPPER RIDGE OVER THE SOUTHERN
PLAINS...WITH THE CWA AND CENTRAL/NORTHERN PLAINS REGION
UNDERNEATH THE SEASONABLY RESPECTABLE WEST-NORTHWEST FLOW ALOFT
ALONG THE PERIPHERY OF THE RIDGE...WITH THE ONLY DISCERNIBLE
SHORTWAVE ON WATER VAPOR IMAGERY ACROSS SD.
STARTING OFF WITH FIRE WEATHER THE NEXT FEW HOURS...IN HINDSIGHT
PROBABLY COULD HAVE/SHOULD HAVE ISSUED A FIRE WEATHER HEADLINE FOR A
HANDFUL OF SOUTHWESTERN COUNTIES AS RELATIVE HUMIDITY VALUES HAVE
CRASHED TO NEAR OR JUST BELOW 20 PERCENT BEHIND THE SURGING WARM
FRONT AND WIND GUSTS HAVE FAIRLY CONSISTENTLY REACHED/TOPPED 25
MPH. HOWEVER...BEING PAST MID AFTERNOON ALREADY...WILL FOREGO
WARNING ISSUANCE AND KEEP ELEVATED FIRE DANGER MENTION IN THE HWO
AND EXTREME FIRE DANGER CATEGORY IN THE GRASSLAND FIRE DANGER
PRODUCT.
TURNING TO THUNDERSTORM CHANCES/SEVERITY...PLENTY OF QUESTIONS
STILL REMAIN REGARDING COVERAGE AND SEVERITY. FOR ONE THING...THE
FAIRLY EXPANSIVE BAND OF MID CLOUDS OVERTAKING MUCH OF THE CWA IS
LIKELY NOT DOING ANY FAVORS FOR HELPING THE CURRENTLY WEAK
CONVECTION MAINLY IN SOUTHWEST ZONES OVERCOME AT LEAST A WEAK
CAPPING INVERSION...WHILE AT THE SAME TIME...HOURLY MESOSCALE
ANALYSIS INDICATES A FAVORABLE ENVIRONMENT FOR SEVERE WITH
1000-2000 J/KG MLCAPE...AND AT LEAST 30KT OF 0-6KM DEEP LAYER
SHEAR...WHICH IS ENOUGH TO GET AT LEAST BRIEF SUPERCELL STRUCTURES
GOING. LEANING ON HIGHER RES MODELS SUCH AS THE HRRR AND 00Z 4K
WRF-NMM...ANTICIPATE STORMS TO GRADUALLY INCREASE IN COVERAGE AND
INTENSITY AS THE LATE AFTERNOON/EVENING WEARS ON...ESPECIALLY
ACROSS THE SOUTHERN 2/3 OF THE CWA. HOWEVER...GIVEN CONTINUED
UNCERTAINTY IN ULTIMATE COVERAGE AND DESIRE TO NOT GET RAIN HOPES UP
TOO MUCH IN THIS DROUGHT PATTERN...HAVE OPTED TO LIMIT POPS TO NO
MORE THAN 30 PERCENT/SCATTERED COVERAGE FOR NOW THROUGH 06Z. ANY
STRONG/SEVERE STORMS THAT GET GOING SHOULD PRIMARILY POSE A WIND
THREAT...GIVEN STEEP LOW LEVEL LAPSE RATES AND CONSIDERABLE
SURFACE TEMP-DEWPOINT DEPRESSIONS AND RESULTANT HIGH CLOUD BASES.
HOWEVER...HAIL TO AROUND QUARTER SIZE CANNOT BE RULED OUT
COMPLETELY. ALTHOUGH SPC HAS OFFICIALLY LEFT THE SOUTHWEST 1/3 OR
SO OF THE CWA OUT OF A SLIGHT RISK...FOR LOCAL PRODUCT PURPOSES
FEEL THAT INCLUDING ALL 30 COUNTIES IN A SLIGHT RISK SCENARIO FOR
WIND/HAIL IS THE WAY TO GO. WOULD EXPECT INDIVIDUAL/MULTICELL
UPDRAFTS TO POSSIBLY CONGEAL INTO A BROKEN SOUTH-SOUTHEAST MOVING
LINE AT SOME POINT THIS EVENING ACROSS THE SOUTHERN CWA...POSSIBLY
ENHANCING A LOCALIZED WIND THREAT. AFTER 06Z...INTRODUCED A 20 POP
ACROSS A FEW FAR SOUTHEASTERN COUNTIES TO ACCOUNT FOR THE
POSSIBILITY OF LINGERING OVERNIGHT STORMS ALONG A VEERING LOW
LEVEL JET AXIS...BUT BY THIS TIME ANTICIPATE ANY SEVERE THREAT TO
BE ON THE WANE. TEMP WISE TONIGHT...NUDGED DOWN LOWS A FEW DEGREES
MOST AREAS PER GUIDANCE CONSENSUS...RANGING FROM LOW 60S FAR
NORTHWEST TO AROUND 70 FAR SOUTHEAST.
GETTING INTO THE DAYTIME HOURS TOMORROW...AND STARTING WITH
TEMPERATURES...AM WONDERING JUST HOW WARM IT IS GOING TO GET WITH
NORTHEAST/EASTERLY BREEZES FLOWING INTO THE CWA IN THE FORM A WEAK
BACK DOOR COLD FRONT FLOWING OUT OF A SURFACE HIGH TO THE
NORTHEAST. HOWEVER...WITH 850MB TEMPERATURES STAYING QUITE
TOASTY...IT WON/T TAKE MUCH MIXING TO GET THINGS CLIMBING FAST. AS
A RESULT...ONLY NUDGED DOWN HIGHS AN AVERAGE OF 1-2 DEGREES MOST
AREAS...STILL CALLING FOR MID-UPPER 90S IN MOST NEB ZONES...AND
100-105 IN KS ZONES AND FURNAS COUNTY AREA. ALTHOUGH CONFIDENCE IS
LOW REGARDING DEWPOINT TRENDS...WITH THE NAM SOMEWHAT INEXPLICABLY
CRASHING DEWPOINTS ALL THE WAY INTO THE UPPER 30S IN NORTHERN
AREAS ALTHOUGH THIS SOLUTION WAS NOT FOLLOWED...CURRENT GRIDS
YIELD HEAT INDEX VALUES IN THE 103-105 RANGE ACROSS PARTS OF KS
ZONES...WHICH COULD NECESSITATE HEAT ADVISORY ISSUANCE.
HOWEVER...WITH SOME UNCERTAINTY REMAINING REGARDING THE STRENGTH
OF THE BACK DOOR COLD FRONT ALONG WITH DEWPOINTS...WILL DEFER TO
OVERNIGHT SHIFT FOR POSSIBLE ADVISORY ISSUANCE...AND CONTINUE TO
MENTION HEAT IN THE HAZARDOUS WEATHER OUTLOOK. AS FOR STORM
CHANCES...LEFT THE MORNING HOURS FREE OF RAIN MENTION...ALTHOUGH
SOME ACTIVITY COULD BE FESTERING RATHER CLOSE TO THE FAR SOUTHERN
EDGE OF THE CWA. FOR THE AFTERNOON HOURS...TRIMMED BACK THE AREA
OF SLIGHT POPS TO ONLY AREAS MAINLY SOUTH OF A CAMBRIDGE-SMITH
CENTER LINE...WHERE THE PRIMARY SURFACE FRONT WILL STALL OUT AND
FOCUS A POSSIBLE INSTABILITY AXIS. AT THIS TIME...NOT ANTICIPATING
A SEVERE THREAT DURING THE DAYTIME PERIOD...BUT IN THIS TRICKY
PATTERN WITH ONE SUBTLE SHORTWAVE AFTER ANOTHER MOVING ACROSS THE
TOP OF THE UPPER RIDGE AXIS...THINGS ARE SUBJECT TO CHANGE ON
SOMEWHAT SHORT NOTICE.
LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. BIGGEST CHALLENGE WILL
BE DETERMINING CHANCES AND TIMING OF ANY PRECIPITATION. ENSEMBLE
MEANS FROM THE ECMWF SEEM THE BEST BET FOR CONSISTENCY. WE BEGIN
THE LONG TERM WITH THE SOUTH CENTRAL PLAINS ANTICYCLONE HEAVILY
INFLUENCING OUR WEATHER...BUT WITH NUMEROUS SHALLOW PERTURBATIONS
ALONG THE PERIPHERY TO THROW UNCERTAINTY INTO THE FORECAST.
UNCERTAINTY ALSO EXISTS FOR WHAT KIND OF SURFACE FEATURES WE MIGHT
HAVE...BUT WE COULD HAVE A FRONT DRAPED ACROSS THE CWA SUNDAY
NIGHT...AS SUGGESTED BY SOME MODELS...THAT COULD BE A FOCUS FOR
ELEVATED CONVECTION...MAINLY ALONG AND JUST NORTH OF THE BOUNDARY.
AN EAST-WEST ORIENTED THETA-E RIDGE IS ADVERTISED TO DRAPE ACROSS
SOUTH CENTRAL NEBRASKA FOR SUNDAY NIGHT...WHICH SUGGESTS THAT
CHANCES OF PRECIPITATION IN THE FORECAST ARE WARRANTED. THERE
COULD BE BOUNDARIES DRAPED ACROSS PARTS OF THE CWA FOR THE BULK OF
THE LONG TERM AS WELL...AS THE FORECAST GETS A LITTLE MUDDLED WITH
POTENTIALLY COMPLICATED SURFACES FEATURES.
THE ANTICYCLONE/RIDGE WILL RETROGRADE SOMEWHAT BY MONDAY...WITH
PERTURBATIONS CONTINUING TO PLAY HAVOC ON ANY CERTAINTY IN THE
FORECAST. THE UPPER LEVEL HIGH WILL CONTINUE TO BE A PROMINENT
FEATURE FOR THE REMAINDER OF THE LONG TERM...HOWEVER. MODELS ARE
KEEPING POTENTIALLY SIGNIFICANT AMOUNTS OF MID-HIGH LEVEL CLOUDINESS
AROUND ON TUESDAY...AND I WILL KNOCK DOWN TEMPERATURES A BIT FROM
THE PREVIOUS FORECAST FOR THIS REASON. WITH THE UPPER LEVEL HIGH IN
PLACE FOR THE REST OF THE WEEK...THIS MEANS MORE ABOVE NORMAL
TEMPERATURES...EVEN WITH ADDITIONAL MID TO UPPER LEVEL CLOUDINESS.
SINCE THE HIGH RETROGRADES A BIT...THIS SHOULD ALLOW A BIT MORE
CHANCES OF PRECIPITATION MORE OFTEN WITH FREQUENT PERTURBATIONS
POSSIBLE. THE ECMWF INDICATES A BIT MORE SIZABLE OF A SHORTWAVE
TROUGH CUTTING THROUGH THE NORTHERN/CENTRAL PLAINS FOR
SATURDAY...WHICH WILL HELP FLATTEN THE RIDGE SOMEWHAT...AND PERHAPS
GIVE A BETTER SHOT AT PRECIPITATION THAN THE LOW CONFIDENCE/LOW
CHANCE PRECIPITATION PATTERN FOR MUCH OF THE LONG TERM. JUDGING BY
THE POTENTIAL STRENGTH OF THE WAVE...THIS COULD BE THE MOST
POTENTIAL FOR SEVERE WEATHER IN THE LONG TERM AS WELL...NOT TO SAY
THERE COULD NOT BE A STRONG STORM WITH ANY CONVECTION THAT MAY FIRE
ALONG THE WAY DURING THE EXTENDED. ALTHOUGH...THE 12Z ECMWF HAS JUST
BACKED OFF OF THE AMPLITUDE OF THE WAVE ON SATURDAY...THIS WAVE
STILL BEARS WATCHING FOR POTENTIAL PRECIPITATION AND PERHAPS STRONG
TO SEVERE WEATHER.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
318 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT ACROSS THE EASTERN CAROLINAS AND VIRGINIA WILL LINGER
AND GRADUALLY DISSIPATE THROUGH TUESDAY. A SERIES OF UPPER LEVEL
DISTURBANCES WILL MOVE SOUTHEASTWARD ACROSS THE REGION ON MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 235 PM SUNDAY...
DIFFUSE COLD FRONT HAS DRIFTED SOUTH SLIGHTLY DURING THE PAST FEW
HOURS WITH NORTHERLY WINDS AT KFAY AND KGSB. DEW POINTS BEHIND THE
FRONT CONTINUE TO FALL TO AROUND 60 IN THE TRIAD WITH MUCH MORE
MOIST DEW POINTS IN THE LOWER 70S ACROSS THE COASTAL PLAIN. MORNING
RAOBS DEPICTED A MUCH DRIER AIR MASS TO THE WEST WITH A PRECIPITABLE
WATER VALUES OF AROUND 0.8/1.1 AT KRNK/KGSO RESPECTIVELY WHILE A PW
OF 1.8 INCHES WAS NOTED AT KMHX. RECENT VISIBLE SATELLITE IMAGERY
DEPICTS A FAIR AMOUNT OF CUMULUS BUT LIMITED VERTICAL GROWTH GIVEN
THE WEAK SUBSIDENCE IN THE WAKE OF A DEPARTING MID LEVEL WAVE AND
DRYING ALOFT.
THE LIMITED THREAT OF CONVECTION THIS AFTERNOON AND EVENING WILL
REMAIN FOCUSED ACROSS THE COASTAL PLAIN...THE SOUTHERN PIEDMONT AND
THE SANDHILLS IN THE VICINITY OF THE SURFACE FRONT...IN A REGION OF
THE DEEPER MOISTURE AND NEAR THE UPPER LEVEL TROUGH AXIS. MOST
CONVECTION ALLOWING MODELS SUGGEST THAT SOME CONVECTION IS POSSIBLE
IN THE EAST TODAY BUT RECENT RUNS OF THE HRRR DOWNPLAY THE COVERAGE
SIGNIFICANTLY. INSTABILITY WILL BE LIMITED TODAY ACROSS THE WEST AND
NORTH WITH MLCAPE VALUES AROUND 500 J/KG...FURTHER EAST IN THE
COASTAL PLAIN MLCAPE VALUES MAY REACH AS HIGH AS 1500 J/KG. MID
LEVEL LAPSE RATES REMAIN RATHER ANEMIC WITH WEAK LOW AND MID LEVEL
FLOW RESULTING IN BULK SHEAR VALUES OF AROUND 15 KTS OR LESS. GIVEN
THE DRY AIR ALOFT...DCAPE VALUES CURRENTLY RANGE AROUND 1300 J/KG
SUGGESTING AT LEAST SOME POTENTIAL FOR STRONG DOWNBURST WINDS WITH A
WELL DEVELOPED CELL. GIVEN THIS ENVIRONMENT...OVERALL STORM STRENGTH
AND ORGANIZATION SHOULD BE LIMITED. PRECIPITATION CHANCES DIMINISH
DURING THE EVENING WITH JUST A LIMITED THREAT OF SHOWERS OR A
THUNDERSTORM OVERNIGHT ACROSS THE EAST AND SOUTH. LOWS TONIGHT
SHOULD DROP INTO THE 67-75 RANGE IN AGREEMENT WITH GUIDANCE. -BLAES
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 310 PM SUNDAY...
A SHORT WAVE TROUGH ACROSS WI/MN/IA ON SUNDAY AFTERNOON ASSOCIATED
WITH A 40 KT MID LEVEL JET WILL DROP SOUTHEAST INTO AND SHARPEN THE
EASTERN U.S. ON MONDAY AN MONDAY NIGHT. THIS FEATURE SHOULD MOVE
ACROSS THE SOUTHERN APPALACHIANS DURING MONDAY AFTERNOON WHICH WILL
SUPPORT THE DEVELOPMENT OF SCATTERED CONVECTION ACROSS THE
CAROLINAS. THE MAIN PUSH OF THE SHORTWAVE WILL MOVE ACROSS GA/SC AND
RESULT IN A SLIGHT COOLING OF TEMPERATURES ALOFT IN CENTRAL NC BUT A
GENERALLY WEAK FLOW ALOFT. THE COLD FRONT DRAPED ACROSS THE
SOUTHEASTERN PORTION OF NC SUNDAY AFTERNOON SHOULD MIGRATE NORTHWEST
EARLY MONDAY AND PROVIDE A FOCUS FOR CONVECTION ACROSS THE EASTERN
PIEDMONT AND COASTAL PAIN. MID LEVEL LAPSE RATES STEEPEN ON MONDAY
AFTERNOON AND MLCAPE VALUES SHOULD RANGE BETWEEN 1000-2000 J/KG
WHILE BULK SHEAR VALUES RANGE AROUND 15 KTS IN CENTRAL NC. PW VALUES
INCREASE SOMEWHAT ON MONDAY AND RANGE FROM 1.4 IN THE TRIAD TO NEAR
2 INCHES IN THE COASTAL PLAIN. THESE PARAMETERS SUGGEST THE
PRIMARY SEVERE WEATHER THREAT ON MONDAY AFTERNOON AND EVENING WILL
BE DAMAGING WINDS FROM WET DOWNBURSTS AND AN ISOLATED MINOR FLOODING
POTENTIAL. LOW LEVEL THICKNESSES WILL CLIMB TO BETWEEN 1410-1420M
MONDAY AFTERNOON...SUGGESTING HIGHS IN THE 88-92 RANGE. SCATTERED
CONVECTION SHOULD PERSIST INTO MONDAY EVENING BUT GENERALLY DIMINISH
OVERNIGHT. LOW TEMPERATURES SHOULD RANGE BETWEEN 68-72 DEGREES.
-BLAES
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 315 PM SUNDAY...
TUESDAY/TUESDAY NIGHT:
THE SYNOPTIC PATTERN OVER THE MID-ATLANTIC/CAROLINAS ON TUE/TUE
NIGHT WILL BE CHARACTERIZED BY TROUGHING ALOFT...ON THE EASTERN
PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL CONUS...
WITH SMALL AMPLITUDE DISTURBANCES PROGRESSING TOWARD THE AREA IN NW
FLOW ALOFT. GIVEN TROUGHING ALOFT IN THE PRESENCE OF A SEASONABLY
MOIST/UNSTABLE AIRMASS...EXPECT ABOVE-NORMAL CHANCES FOR SHOWERS AND
STORMS...PRIMARILY DURING THE AFTERNOON/EVENING HOURS. HOWEVER...THE
TIMING/LOCATION/COVERAGE OF CONVECTION IS STILL UNCERTAIN AND WILL
HIGHLY DEPEND ON THE EVOLUTION OF SMALL AMPLITUDE DISTURBANCES
EXPECTED TO PROGRESS TOWARD THE REGION IN NW FLOW ALOFT. WITH THE
ABOVE IN MIND...WILL INDICATE A 50% CHANCE OF SHOWERS/STORMS
EVERYWHERE ON TUE...WITH CHANCES DECREASING TO 20% AFTER MIDNIGHT.
HIGHS ON TUE SHOULD BE NEAR NORMAL (UPPER 80S/LOWER 90S) BASED ON
1000-850 MB THICKNESSES IN VICINITY OF 1415 METERS. LOWS WED MORNING
SHOULD ALSO SHOULD BE NEAR NORMAL (UPPER 60S/LOWER 70S). THE PRIMARY
UNCERTAINTY WITH TEMPERATURES WILL BE THE TIMING/LOCATION OF
CONVECTION AND CLOUD COVER ASSOCIATED WITH THE REMNANTS OF
CONVECTION OVER OR UPSTREAM OF THE AREA. AS MENTIONED IN THE SPC DAY
3 CONVECTIVE OUTLOOK...THERE MAY BE AN INCREASED THREAT FOR SEVERE
THUNDERSTORMS TUE AFTERNOON AND EVENING...THOUGH UNCERTAINTY
PERSISTS. MODEL GUIDANCE IS INDICATING RICH BOUNDARY LAYER MOISTURE
TUE AFT/EVE...FOCUSED SHORTWAVE ENERGY DIGGING TOWARD THE AREA IN
VICINITY OF PEAK HEATING...STRENGTHENING MID-UPPER LEVEL FLOW/DEEP
LAYER SHEAR...AND A POTENTIAL FOR MODESTLY STEEP (6-7 C/KM)
MID-LEVEL LAPSE RATES ADVECTING SOUTHEAST TO THE SOUTHERN
APPALACHIANS AND PORTIONS OF THE MID-ATLANTIC/CAROLINAS VIA NW FLOW
ALOFT.
WEDNESDAY THROUGH SUNDAY:
THE SYNOPTIC PATTERN OVER THE CAROLINAS AND MID-ATLANTIC WED-SUN
WILL BE CHARACTERIZED INITIALLY (WED/THU) BY NW FLOW ALOFT...
TRANSITIONING (FRI/SAT/SUN) TO WESTERLY FLOW ALOFT AS THE UPPER
LEVEL RIDGE OVER THE CENTRAL CONUS FLATTENS AND EXTENDS EAST TOWARD
THE CAROLINAS/SOUTHEAST. PRECIPITATION CHANCES...I.E. THE TIMING/
LOCATION/COVERAGE OF CONVECTION...WILL BE HIGHLY DEPENDENT ON THE
EVOLUTION OF SMALL AMPLITUDE DISTURBANCES PROGRESSING SOUTHEAST FROM
THE UPPER MIDWEST/CENTRAL MS RIVER VALLEY INTO THE MID-ATLANTIC AND
CAROLINAS ON WED/THU...WITH A POTENTIAL FOR ENHANCED COVERAGE AND
SEVERE WEATHER. THOUGH UNCERTAINTY INCREASES BY NEXT WEEKEND...
CONVECTION MAY BECOME MORE ISOLATED IN NATURE FRI/SAT/SUN AS THE
MAIN BELT OF WESTERLIES SHIFTS FURTHER NORTH INTO THE MID-ATLANTIC
AND FORCING BECOMES INCREASINGLY CONFINED TO THE PIEDMONT TROUGH/
SEABREEZE...MORE TYPICAL FOR THIS TIME OF YEAR. WILL INDICATE
CHANCES FOR SHOWERS/STORMS SLIGHTLY ABOVE CLIMATOLOGY IN THE 30-40%
RANGE WED/THU...WITH A SLIGHT CHANCE (20%) PERSISTING DURING THE
OVERNIGHT HOURS. ON FRI/SAT/SUN WILL TREND CLOSER TOWARD CLIMATOLOGY
W/REGARD TO CHANCES FOR CONVECTION. TEMPERATURES WILL PRIMARILY
DEPEND ON THE EVOLUTION OF CONVECTION AND ASSOCIATED CLOUD COVER
WED/THU...WITH 1000-850 MB THICKNESSES SUGGESTING HIGHS AND LOWS
NEAR NORMAL...IN THE UPPER 80S TO LOWER 90S AND UPPER 60S TO LOWER
70S. SLIGHTLY ABOVE NORMAL TEMPS (LOWER/MID 90S) WILL BE POSSIBLE
FRI/SAT/SUN GIVEN A RELATIVELY DECREASED POTENTIAL FOR CONVECTION
AND RISING HEIGHTS ALOFT. -VINCENT
&&
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
AS OF 135 PM SUNDAY...
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS CENTRAL NC
THROUGH THE AFTERNOON AND EVENING HOURS WITH LIGHT...MAINLY
NORTHEAST/EASTERLY WINDS. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE ACROSS THE COASTAL PLAIN AND SANDHILLS WHICH COULD IMPACT
KFAY/KRWI. COVERAGE AND CONFIDENCE IS TOO LOW TO INCLUDE A TSRA IN
THE TAF BUT HAVE INCLUDED SHRA AT KFAY WHICH HAS THE GREATEST CHANCE
OF CONVECTION. A STALLED FRONT ACROSS THE COASTAL PLAIN WILL DRIFT
NORTH TONIGHT AND RESULT IN A WIND SHIFT TO SOUTHEAST/SOUTHERLY
WINDS IN THE COASTAL PLAIN AND SANDHILLS WHICH SHOULD RESULT IN
INCREASED LOW LEVEL MOISTURE AND THE DEVELOPMENT OF FOG AND STRATUS.
HAVE HIGHLIGHTED THE POTENTIAL FOR THIS AT KFAY/KRWI WITH IFR/MAYBE
LIFR CONDITIONS POSSIBLE LATE TONIGHT BETWEEN 08-12Z. AFTER MORNING
STRATUS AND FOG...GENERALLY FAIR WEATHER AND VFR CONDITIONS ARE
EXPECTED THROUGH EARLY MONDAY AFTERNOON.
LOOKING BEYOND 18Z MONDAY... SCATTERED THUNDERSTORMS ARE POSSIBLE AT
RDU/RWI/FAY ON MONDAY AFTERNOON/EVENING WITH A PERIOD OF MVFR/IFR
FOG/STRATUS POSSIBLE EARLY TUESDAY MORNING. MORE NUMEROUS
THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON/EVENING. A MORE TYPICAL
THREAT OF SUMMERTIME AFTERNOON/EVENING THUNDERSTORMS AND EARLY
MORNING FOG/STRATUS CONTINUES ON WEDNESDAY AND THURSDAY. -BLAES
&&
.EQUIPMENT...
KRAX...THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...VINCENT
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT ACROSS THE EASTERN CAROLINAS AND VIRGINIA WILL LINGER
AND GRADUALLY DISSIPATE THROUGH TUESDAY. A SERIES OF UPPER LEVEL
DISTURBANCES WILL MOVE SOUTHEASTWARD ACROSS THE REGION ON MONDAY AND
TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 235 PM SUNDAY...
DIFFUSE COLD FRONT HAS DRIFTED SOUTH SLIGHTLY DURING THE PAST FEW
HOURS WITH NORTHERLY WINDS AT KFAY AND KGSB. DEW POINTS BEHIND THE
FRONT CONTINUE TO FALL TO AROUND 60 IN THE TRIAD WITH MUCH MORE
MOIST DEW POINTS IN THE LOWER 70S ACROSS THE COASTAL PLAIN. MORNING
RAOBS DEPICTED A MUCH DRIER AIR MASS TO THE WEST WITH A PRECIPITABLE
WATER VALUES OF AROUND 0.8/1.1 AT KRNK/KGSO RESPECTIVELY WHILE A PW
OF 1.8 INCHES WAS NOTED AT KMHX. RECENT VISIBLE SATELLITE IMAGERY
DEPICTS A FAIR AMOUNT OF CUMULUS BUT LIMITED VERTICAL GROWTH GIVEN
THE WEAK SUBSIDENCE IN THE WAKE OF A DEPARTING MID LEVEL WAVE AND
DRYING ALOFT.
THE LIMITED THREAT OF CONVECTION THIS AFTERNOON AND EVENING WILL
REMAIN FOCUSED ACROSS THE COASTAL PLAIN...THE SOUTHERN PIEDMONT AND
THE SANDHILLS IN THE VICINITY OF THE SURFACE FRONT...IN A REGION OF
THE DEEPER MOISTURE AND NEAR THE UPPER LEVEL TROUGH AXIS. MOST
CONVECTION ALLOWING MODELS SUGGEST THAT SOME CONVECTION IS POSSIBLE
IN THE EAST TODAY BUT RECENT RUNS OF THE HRRR DOWNPLAY THE COVERAGE
SIGNIFICANTLY. INSTABILITY WILL BE LIMITED TODAY ACROSS THE WEST AND
NORTH WITH MLCAPE VALUES AROUND 500 J/KG...FURTHER EAST IN THE
COASTAL PLAIN MLCAPE VALUES MAY REACH AS HIGH AS 1500 J/KG. MID
LEVEL LAPSE RATES REMAIN RATHER ANEMIC WITH WEAK LOW AND MID LEVEL
FLOW RESULTING IN BULK SHEAR VALUES OF AROUND 15 KTS OR LESS. GIVEN
THE DRY AIR ALOFT...DCAPE VALUES CURRENTLY RANGE AROUND 1300 J/KG
SUGGESTING AT LEAST SOME POTENTIAL FOR STRONG DOWNBURST WINDS WITH A
WELL DEVELOPED CELL. GIVEN THIS ENVIRONMENT...OVERALL STORM STRENGTH
AND ORGANIZATION SHOULD BE LIMITED. PRECIPITATION CHANCES DIMINISH
DURING THE EVENING WITH JUST A LIMITED THREAT OF SHOWERS OR A
THUNDERSTORM OVERNIGHT ACROSS THE EAST AND SOUTH. LOWS TONIGHT
SHOULD DROP INTO THE 67-75 RANGE IN AGREEMENT WITH GUIDANCE. -BLAES
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
AS OF 310 PM SUNDAY...
A SHORT WAVE TROUGH ACROSS WI/MN/IA ON SUNDAY AFTERNOON ASSOCIATED
WITH A 40 KT MID LEVEL JET WILL DROP SOUTHEAST INTO AND SHARPEN THE
EASTERN U.S. ON MONDAY AN MONDAY NIGHT. THIS FEATURE SHOULD MOVE
ACROSS THE SOUTHERN APPALACHIANS DURING MONDAY AFTERNOON WHICH WILL
SUPPORT THE DEVELOPMENT OF SCATTERED CONVECTION ACROSS THE
CAROLINAS. THE MAIN PUSH OF THE SHORTWAVE WILL MOVE ACROSS GA/SC AND
RESULT IN A SLIGHT COOLING OF TEMPERATURES ALOFT IN CENTRAL NC BUT A
GENERALLY WEAK FLOW ALOFT. THE COLD FRONT DRAPED ACROSS THE
SOUTHEASTERN PORTION OF NC SUNDAY AFTERNOON SHOULD MIGRATE NORTHWEST
EARLY MONDAY AND PROVIDE A FOCUS FOR CONVECTION ACROSS THE EASTERN
PIEDMONT AND COASTAL PAIN. MID LEVEL LAPSE RATES STEEPEN ON MONDAY
AFTERNOON AND MLCAPE VALUES SHOULD RANGE BETWEEN 1000-2000 J/KG
WHILE BULK SHEAR VALUES RANGE AROUND 15 KTS IN CENTRAL NC. PW VALUES
INCREASE SOMEWHAT ON MONDAY AND RANGE FROM 1.4 IN THE TRIAD TO NEAR
2 INCHES IN THE COASTAL PLAIN. THESE PARAMETERS SUGGEST THE
PRIMARY SEVERE WEATHER THREAT ON MONDAY AFTERNOON AND EVENING WILL
BE DAMAGING WINDS FROM WET DOWNBURSTS AND AN ISOLATED MINOR FLOODING
POTENTIAL. LOW LEVEL THICKNESSES WILL CLIMB TO BETWEEN 1410-1420M
MONDAY AFTERNOON...SUGGESTING HIGHS IN THE 88-92 RANGE. SCATTERED
CONVECTION SHOULD PERSIST INTO MONDAY EVENING BUT GENERALLY DIMINISH
OVERNIGHT. LOW TEMPERATURES SHOULD RANGE BETWEEN 68-72 DEGREES.
-BLAES
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN RELATIVELY UNCHANGED
THROUGH THE REMAINDER OF THE WEEK...WITH GENERALLY RIDGING OVER THE
CENTRAL TO WESTERN US AND TROUGHING OVER THE EAST. WHILE NORTHWEST
FLOW WILL CONTINUE ALOFT AND WILL SUPPORT DIURNAL CONVECTION ALONG
THE HIGHER TERRAIN/LEE TROUGH/SEA-BREEZE...IT APPEARS CONVECTION
WILL BE MORE WIDELY SCATTERED. MEDIUM RANGE GUIDANCE
PROJECTS LOW LEVEL THICKNESSES HOLDING NEAR 1425M EACH DAY...WHICH
SHOULD LEAD TO HIGHS IN THE LOWER 90S WITH LOWS CONSISTENTLY IN THE
LOWER 70S.
&&
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
AS OF 135 PM SUNDAY...
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS CENTRAL NC
THROUGH THE AFTERNOON AND EVENING HOURS WITH LIGHT...MAINLY
NORTHEAST/EASTERLY WINDS. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE ACROSS THE COASTAL PLAIN AND SANDHILLS WHICH COULD IMPACT
KFAY/KRWI. COVERAGE AND CONFIDENCE IS TOO LOW TO INCLUDE A TSRA IN
THE TAF BUT HAVE INCLUDED SHRA AT KFAY WHICH HAS THE GREATEST CHANCE
OF CONVECTION. A STALLED FRONT ACROSS THE COASTAL PLAIN WILL DRIFT
NORTH TONIGHT AND RESULT IN A WIND SHIFT TO SOUTHEAST/SOUTHERLY
WINDS IN THE COASTAL PLAIN AND SANDHILLS WHICH SHOULD RESULT IN
INCREASED LOW LEVEL MOISTURE AND THE DEVELOPMENT OF FOG AND STRATUS.
HAVE HIGHLIGHTED THE POTENTIAL FOR THIS AT KFAY/KRWI WITH IFR/MAYBE
LIFR CONDITIONS POSSIBLE LATE TONIGHT BETWEEN 08-12Z. AFTER MORNING
STRATUS AND FOG...GENERALLY FAIR WEATHER AND VFR CONDITIONS ARE
EXPECTED THROUGH EARLY MONDAY AFTERNOON.
LOOKING BEYOND 18Z MONDAY... SCATTERED THUNDERSTORMS ARE POSSIBLE AT
RDU/RWI/FAY ON MONDAY AFTERNOON/EVENING WITH A PERIOD OF MVFR/IFR
FOG/STRATUS POSSIBLE EARLY TUESDAY MORNING. MORE NUMEROUS
THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON/EVENING. A MORE TYPICAL
THREAT OF SUMMERTIME AFTERNOON/EVENING THUNDERSTORMS AND EARLY
MORNING FOG/STRATUS CONTINUES ON WEDNESDAY AND THURSDAY. -BLAES
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...SMITH
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 PM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL STALL OUT OVER EASTERN VIRGINIA AND CENTRAL
NORTH CAROLINA TODAY... AND REMAIN THERE THROUGH MONDAY AS IT SLOWLY
WEAKENS AND DISSIPATES. A SERIES OF UPPER LEVEL DISTURBANCES WILL
MOVE SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 235 PM SUNDAY...
DIFFUSE COLD FRONT HAS DRIFTED SOUTH SLIGHTLY DURING THE PAST FEW
HOURS WITH NORTHERLY WINDS AT KFAY AND KGSB. DEW POINTS BEHIND THE
FRONT CONTINUE TO FALL TO AROUND 60 IN THE TRIAD WITH MUCH MORE
MOIST DEW POINTS IN THE LOWER 70S ACROSS THE COASTAL PLAIN. MORNING
RAOBS DEPICTED A MUCH DRIER AIR MASS TO THE WEST WITH A PRECIPITABLE
WATER VALUES OF AROUND 0.8/1.1 AT KRNK/KGSO RESPECTIVELY WHILE A PW
OF 1.8 INCHES WAS NOTED AT KMHX. RECENT VISIBLE SATELLITE IMAGERY
DEPICTS A FAIR AMOUNT OF CUMULUS BUT LIMITED VERTICAL GROWTH GIVEN
THE WEAK SUBSIDENCE IN THE WAKE OF A DEPARTING MID LEVEL WAVE AND
DRYING ALOFT.
THE LIMITED THREAT OF CONVECTION THIS AFTERNOON AND EVENING WILL
REMAIN FOCUSED ACROSS THE COASTAL PLAIN...THE SOUTHERN PIEDMONT AND
THE SANDHILLS IN THE VICINITY OF THE SURFACE FRONT...IN A REGION OF
THE DEEPER MOISTURE AND NEAR THE UPPER LEVEL TROUGH AXIS. MOST
CONVECTION ALLOWING MODELS SUGGEST THAT SOME CONVECTION IS POSSIBLE
IN THE EAST TODAY BUT RECENT RUNS OF THE HRRR DOWNPLAY THE COVERAGE
SIGNIFICANTLY. INSTABILITY WILL BE LIMITED TODAY ACROSS THE WEST AND
NORTH WITH MLCAPE VALUES AROUND 500 J/KG...FURTHER EAST IN THE
COASTAL PLAIN MLCAPE VALUES MAY REACH AS HIGH AS 1500 J/KG. MID
LEVEL LAPSE RATES REMAIN RATHER ANEMIC WITH WEAK LOW AND MID LEVEL
FLOW RESULTING IN BULK SHEAR VALUES OF AROUND 15 KTS OR LESS. GIVEN
THE DRY AIR ALOFT...DCAPE VALUES CURRENTLY RANGE AROUND 1300 J/KG
SUGGESTING AT LEAST SOME POTENTIAL FOR STRONG DOWNBURST WINDS WITH A
WELL DEVELOPED CELL. GIVEN THIS ENVIRONMENT...OVERALL STORM STRENGTH
AND ORGANIZATION SHOULD BE LIMITED. PRECIPITATION CHANCES DIMINISH
DURING THE EVENING WITH JUST A LIMITED THREAT OF SHOWERS OR A
THUNDERSTORM OVERNIGHT ACROSS THE EAST AND SOUTH. LOWS TONIGHT
SHOULD DROP INTO THE 67-75 RANGE IN AGREEMENT WITH GUIDANCE. -BLAES
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...
MONDAY....
WITH THE UPPER RIDGE PARKED OVER THE CENTRAL US...THE UPPER TROUGH
WILL PERSIST OVER THE EASTERN US THIS WEEK...WITH MODELS SHOWING A
PAIR OF DISTURBANCES ON THE NORTHWEST FLOW ALOFT THAT SHOULD AUGMENT
CONVECTIVE POTENTIAL MONDAY AND TUESDAY. THE STALLED OUT FRONTAL
ZONE IN THE VICINITY OF THE EASTERN PIEDMONT AND COASTAL PLAIN
SHOULD BE THE PRIMARY FOCUS FOR CONVECTION ON MONDAY...THOUGH THE
NAM/ECMWF SUGGEST THE BOUNDARY MAY SHIFT BACK WESTWARD AS
SOUTHEASTERLY LOW LEVEL FLOW DEVELOPS IN RESPONSE TO A WEAK 850MB
WAVE DRIFTING NORTHEAST OUT OF SC. DESPITE BACKED SURFACE
WINDS/SHORT CURVED HODOGRAPHS AND MLCAPE VALUES PROJECTED TO REACH
1500 J/KG...THE OVERALL WEAK TROPOSPHERIC FLOW FLOW SHOULD LIMIT THE
SEVERITY OF STORMS MONDAY AFTERNOON. PW VALUES SURGING TO AROUND 2
INCHES SUGGEST THE MAIN THREAT FORM STORMS WOULD BE DAMAGING WINDS
VA PRECIP LOADED AND SOME ISOLATED MINOR FLOODING POTENTIAL.
LOW LEVEL THICKNESSES OF AROUND 1415M ARE FORECAST MONDAY
AFTERNOON... WHICH IS ONLY ABOUT 5M ABOVE NORMAL FOR EARLY AUGUST.
HIGHS 89-92.
MONDAY NIGHT...
A FEW SHOWERS/STORMS COULD PERSIST INTO THE OVERNIGHT HOURS AS
OUTFLOW BOUNDARY LINGER IN THE MOIST AIRMASS...BUT THE COVERAGE OF
CONVECTION SHOULD DECREASE SIGNIFICANTLY AFTER SUNSET. LOWS IN THE
LOWER 70S.
TUESDAY/TUESDAY NIGHT...
CONDITIONS ARE EXPECTED TO AGAIN BE RIPE FOR SCATTERED TO NUMEROUS
STORMS TUESDAY AS MODELS AGREE ON ANOTHER...MORE PRONOUNCED
DISTURBANCE ALOFT DIVING INTO THE BASE OF THE UPPER TROUGH DURING
PEAK HEATING. WITH THE LEE TROUGH EXPECTED TO AGAIN BE THE MAIN LOW
LEVEL FOCUS FOR DEVELOPMENT...STRONG HEATING (HIGHS IN THE LOWER
90S) AND DESTABILIZATION...ALONG WITH SLIGHTLY BETTER DEEP LAYER
SHEAR SUPPORT A BETTER SEVERE THREAT. THERE IS THE POTENTIAL FOR
SHOWERS AND STORMS TO CONTINUE INTO THE OVERNIGHT PERIOD TUESDAY
NIGHT WITH MODELS SHOWING AN 850MB TROUGH PUSHING EAST THROUGH THE
AREA AFTER 00Z AS THE UPPER TROUGH AXIS SHIFTS EAST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN RELATIVELY UNCHANGED
THROUGH THE REMAINDER OF THE WEEK...WITH GENERALLY RIDGING OVER THE
CENTRAL TO WESTERN US AND TROUGHING OVER THE EAST. WHILE NORTHWEST
FLOW WILL CONTINUE ALOFT AND WILL SUPPORT DIURNAL CONVECTION ALONG
THE HIGHER TERRAIN/LEE TROUGH/SEA-BREEZE...IT APPEARS CONVECTION
WILL BE MORE WIDELY SCATTERED. MEDIUM RANGE GUIDANCE
PROJECTS LOW LEVEL THICKNESSES HOLDING NEAR 1425M EACH DAY...WHICH
SHOULD LEAD TO HIGHS IN THE LOWER 90S WITH LOWS CONSISTENTLY IN THE
LOWER 70S.
&&
.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
AS OF 135 PM SUNDAY...
VFR CONDITIONS ARE GENERALLY EXPECTED TO CONTINUE ACROSS CENTRAL NC
THROUGH THE AFTERNOON AND EVENING HOURS WITH LIGHT...MAINLY
NORTHEAST/EASTERLY WINDS. AN ISOLATED SHOWER OR THUNDERSTORM IS
POSSIBLE ACROSS THE COASTAL PLAIN AND SANDHILLS WHICH COULD IMPACT
KFAY/KRWI. COVERAGE AND CONFIDENCE IS TOO LOW TO INCLUDE A TSRA IN
THE TAF BUT HAVE INCLUDED SHRA AT KFAY WHICH HAS THE GREATEST CHANCE
OF CONVECTION. A STALLED FRONT ACROSS THE COASTAL PLAIN WILL DRIFT
NORTH TONIGHT AND RESULT IN A WIND SHIFT TO SOUTHEAST/SOUTHERLY
WINDS IN THE COASTAL PLAIN AND SANDHILLS WHICH SHOULD RESULT IN
INCREASED LOW LEVEL MOISTURE AND THE DEVELOPMENT OF FOG AND STRATUS.
HAVE HIGHLIGHTED THE POTENTIAL FOR THIS AT KFAY/KRWI WITH IFR/MAYBE
LIFR CONDITIONS POSSIBLE LATE TONIGHT BETWEEN 08-12Z. AFTER MORNING
STRATUS AND FOG...GENERALLY FAIR WEATHER AND VFR CONDITIONS ARE
EXPECTED THROUGH EARLY MONDAY AFTERNOON.
LOOKING BEYOND 18Z MONDAY... SCATTERED THUNDERSTORMS ARE POSSIBLE AT
RDU/RWI/FAY ON MONDAY AFTERNOON/EVENING WITH A PERIOD OF MVFR/IFR
FOG/STRATUS POSSIBLE EARLY TUESDAY MORNING. MORE NUMEROUS
THUNDERSTORMS ARE EXPECTED TUESDAY AFTERNOON/EVENING. A MORE TYPICAL
THREAT OF SUMMERTIME AFTERNOON/EVENING THUNDERSTORMS AND EARLY
MORNING FOG/STRATUS CONTINUES ON WEDNESDAY AND THURSDAY. -BLAES
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BLAES
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY TOWARD THE SOUTHEAST THROUGH THE AREA
TODAY... BEFORE STALLING OUT OVER EASTERN VIRGINIA AND CENTRAL NORTH
CAROLINA THROUGH MONDAY. THE FRONT WILL WEAKEN AND DISSIPATE BY
MONDAY NIGHT. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE
SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY... RESULTING IN
UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 AM SUNDAY...
OVERALL PICTURE: THE LATEST SURFACE ANALYSIS SHOWS THE SURFACE FRONT
HAVING DRIFTED SOUTHEASTWARD IN THE LAST SEVERAL HOURS... TO A
POSITION ACROSS CENTRAL NC TO THE NC FOOTHILLS TO EXTREME NRN GA/AL.
IN THE MID LEVELS... WE REMAIN IN A PATTERN FEATURING A STRONG
ANTICYCLONE CENTERED OVER OK AND THE TX PANHANDLE AND TROUGHING IN
THE EAST. A WEAK PERTURBATION IS NOW PASSING THROUGH THE BASE OF THE
TROUGH THROUGH VA AND NRN NC... WITH A SECOND WEAKENING WAVE
DROPPING THROUGH KY AND A THIRD STRONGER WAVE OVER MN... ALSO
DROPPING TOWARD THE SE. WATER VAPOR IMAGERY AND BLENDED TOTAL PRECIP
WATER IMAGERY BOTH INDICATE DRY AIR HAVING MOVED INTO THE NRN/WRN
PORTIONS OF CENTRAL NC AND PW VALUES VERY CLOSE TO SEASONAL NORMALS
ACROSS THE REGION.
FOR TODAY/TONIGHT: PATCHY SHOWERS PERSIST OVER THE FAR SOUTHEAST
FRINGES OF THE FORECAST AREA... BUT OTHERWISE THE STRONG TO SEVERE
STORMS FROM LAST EVENING HAVE DIMINISHED... LEAVING JUST A COUPLE
HUNDRED J/KG OF SURFACE CAPE OVER THE EXTREME SOUTHERN SECTIONS AND
WEAK LAPSE RATES AREAWIDE. WITH WANING MOISTURE AND SUPPORT FOR
LIFT... WE SHOULD SEE A CONTINUE DISSOLUTION OF WHAT LITTLE PRECIP
IS OUT THERE BY DAWN. THE DEPARTING WEAK WAVE... THE INCOMING DRIER
AIR THROUGH THE COLUMN AS EXHIBITED ON GFS FORECAST SOUNDINGS AS
WELL AS UPSTREAM OBSERVED SOUNDINGS... AND THE EXITING UPPER
DIVERGENCE AS THE RIGHT ENTRANCE REGION OF THE JET ORIENTED ALONG
THE NORTHEAST COAST MOVES OFFSHORE SHOULD ALL WORK IN CONCERT TO
INHIBIT CONVECTION THROUGH THIS MORNING. WE SHOULD SEE ANOTHER
INLAND-TRACKING SEA BREEZE DEVELOP BY MIDDAY... PROVIDED THAT THE
CURRENT EXPANSE OF MID AND HIGH CLOUDS OVER THE COASTAL PLAIN AND
COASTAL AREA THINS OUT SUFFICIENTLY. IF IT DOES... WE SHOULD SEE
LIFT FORCED ALONG THE SEA BREEZE IN CONJUNCTION WITH DAYTIME HEATING
AND MOIST NEAR-SURFACE AIR TO GENERATE SHOWERS AND STORMS OVER THE
SOUTHEASTERN FORECAST AREA BY EARLY AFTERNOON. THE NEAR TO SLIGHTLY
BELOW NORMAL PW VALUES OVER THE NRN/WRN FORECAST AREA SHOULD LIMIT
INLAND PENETRATION OF ANY SUCH SEA BREEZE CONVECTION... AND
LINGERING SUBSIDENCE IN THE WAKE OF THE WEAK WAVE MAY FURTHER HINDER
STORM DEVELOPMENT. AS SUCH... HAVE CONFINED SCATTERED STORMS TO JUST
THE SOUTHEASTERN FORECAST AREA WITH NO BETTER THAN ISOLATED
SPREADING INTO THE ERN PIEDMONT AND WRN SANDHILLS LATER IN THE
AFTERNOON AS SHOWN BY THE SPC CONVECTION-ALLOWING 4-KM WRF MODEL...
BEFORE LOSS OF HEATING LEADS TO GRADUAL DISSIPATION OF CONVECTION
THROUGH THE MID TO LATE EVENING. INSTABILITY SHOULD BE MARGINAL AT
BEST WITH MLCAPE UNDER 500 J/KG OVER ALL BUT THE FAR SRN/ERN
COUNTIES... AND POOR DEEP-LAYER SHEAR WILL CUT BACK ON STORM
DEVELOPMENT... STRENGTH... AND ORGANIZATION AS WELL. THICKNESSES
THIS MORNING ARE EXPECTED TO BE SIMILAR TO YESTERDAY`S BUT NOT
RISING QUITE AS MUCH DURING THE DAY DUE TO SLIGHT COOLING AT 850 MB.
FACTORING THIS IN... EXPECT HIGHS OF 91-96... JUST A SHADE UNDER
SATURDAY`S HIGHS. WILL FOLLOW PERSISTENCE WITH LOWS... 68-74.
FORECAST SOUNDINGS AND STATISTICAL GUIDANCE ALONG WITH THE OVERALL
PATTERN ALL FAVOR FOG DEVELOPMENT LATE TONIGHT. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...
MONDAY....
WITH THE UPPER RIDGE PARKED OVER THE CENTRAL US...THE UPPER TROUGH
WILL PERSIST OVER THE EASTERN US THIS WEEK...WITH MODELS SHOWING A
PAIR OF DISTURBANCES ON THE NORTHWEST FLOW ALOFT THAT SHOULD AUGMENT
CONVECTIVE POTENTIAL MONDAY AND TUESDAY. THE STALLED OUT FRONTAL
ZONE IN THE VICINITY OF THE EASTERN PIEDMONT AND COASTAL PLAIN
SHOULD BE THE PRIMARY FOCUS FOR CONVECTION ON MONDAY...THOUGH THE
NAM/ECMWF SUGGEST THE BOUNDARY MAY SHIFT BACK WESTWARD AS
SOUTHEASTERLY LOW LEVEL FLOW DEVELOPS IN RESPONSE TO A WEAK 850MB
WAVE DRIFTING NORTHEAST OUT OF SC. DESPITE BACKED SURFACE
WINDS/SHORT CURVED HODOGRAPHS AND MLCAPE VALUES PROJECTED TO REACH
1500 J/KG...THE OVERALL WEAK TROPOSPHERIC FLOW FLOW SHOULD LIMIT THE
SEVERITY OF STORMS MONDAY AFTERNOON. PW VALUES SURGING TO AROUND 2
INCHES SUGGEST THE MAIN THREAT FORM STORMS WOULD BE DAMAGING WINDS
VA PRECIP LOADED AND SOME ISOLATED MINOR FLOODING POTENTIAL.
LOW LEVEL THICKNESSES OF AROUND 1415M ARE FORECAST MONDAY
AFTERNOON... WHICH IS ONLY ABOUT 5M ABOVE NORMAL FOR EARLY AUGUST.
HIGHS 89-92.
MONDAY NIGHT...
A FEW SHOWERS/STORMS COULD PERSIST INTO THE OVERNIGHT HOURS AS
OUTFLOW BOUNDARY LINGER IN THE MOIST AIRMASS...BUT THE COVERAGE OF
CONVECTION SHOULD DECREASE SIGNIFICANTLY AFTER SUNSET. LOWS IN THE
LOWER 70S.
TUESDAY/TUESDAY NIGHT...
CONDITIONS ARE EXPECTED TO AGAIN BE RIPE FOR SCATTERED TO NUMEROUS
STORMS TUESDAY AS MODELS AGREE ON ANOTHER...MORE PRONOUNCED
DISTURBANCE ALOFT DIVING INTO THE BASE OF THE UPPER TROUGH DURING
PEAK HEATING. WITH THE LEE TROUGH EXPECTED TO AGAIN BE THE MAIN LOW
LEVEL FOCUS FOR DEVELOPMENT...STRONG HEATING (HIGHS IN THE LOWER
90S) AND DESTABILIZATION...ALONG WITH SLIGHTLY BETTER DEEP LAYER
SHEAR SUPPORT A BETTER SEVERE THREAT. THERE IS THE POTENTIAL FOR
SHOWERS AND STORMS TO CONTINUE INTO THE OVERNIGHT PERIOD TUESDAY
NIGHT WITH MODELS SHOWING AN 850MB TROUGH PUSHING EAST THROUGH THE
AREA AFTER 00Z AS THE UPPER TROUGH AXIS SHIFTS EAST OF THE AREA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...
THE LONGWAVE PATTERN IS EXPECTED TO REMAIN RELATIVELY UNCHANGED
THROUGH THE REMAINDER OF THE WEEK...WITH GENERALLY RIDGING OVER THE
CENTRAL TO WESTERN US AND TROUGHING OVER THE EAST. WHILE NORTHWEST
FLOW WILL CONTINUE ALOFT AND WILL SUPPORT DIURNAL CONVECTION ALONG
THE HIGHER TERRAIN/LEE TROUGH/SEA-BREEZE...IT APPEARS CONVECTION
WILL BE MORE WIDELY SCATTERED. MEDIUM RANGE GUIDANCE
PROJECTS LOW LEVEL THICKNESSES HOLDING NEAR 1425M EACH DAY...WHICH
SHOULD LEAD TO HIGHS IN THE LOWER 90S WITH LOWS CONSISTENTLY IN THE
LOWER 70S.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO LAST FOR A FEW MORE HOURS OVERNIGHT
BEFORE THEY GIVE WAY TO MVFR VSBYS AS PATCHY LIGHT FOG DEVELOPS NEAR
RDU/RWI/FAY... LOCATIONS THAT RECEIVED A SOAKING RAIN FROM
THUNDERSTORMS LAST EVENING. BUT THE CONSIDERABLE MID AND HIGH CLOUDS
AT THESE SITES SHOULD INHIBIT RADIATIONAL COOLING AND BOTH DELAY
DEVELOPMENT AND LIMIT DENSITY OF FOG. RDU SHOULD SEE THE BEST CHANCE
OF SEVERAL HOURS OF MVFR FOG -- POSSIBLY DROPPING TO IFR -- GIVEN
THE COMBINATION OF PLENTY OF RAIN... LIGHT WINDS... AND AN EARLY
CLEARING OF CONVECTIVE DEBRIS MID AND HIGH CLOUDS. SURE ENOUGH...
THE LATEST HRRR EXPERIMENTAL AVIATION MODEL OUTPUT PLACES A PATCH OF
LOW VSBY NEAR RDU TOWARD MORNING. AT GSO/INT... ANY FOG IS EXPECTED
TO BE MORE THIN AND SHORT-LIVED AS THESE TWO SITES RECEIVED ONLY
BRIEF LIGHT RAIN NEAR THE TERMINALS... AND DRIER AIR IS SLOWLY
WORKING INTO THE TRIAD AREA FROM THE NORTHWEST. ANY FOG WILL LIFT
AND MIX OUT WITH HEATING BY 13Z-14Z. VFR CIGS ARE EXPECTED TO FORM
AT ALL SITES AFTER 16Z... WITH MORE EXPANSIVE CLOUD COVER AT
RDU/RWI/FAY. A FEW STORMS ARE EXPECTED NEAR FAY AFTER 17Z... EAST OF
A WEAKENING FRONT STALLED ACROSS THE AREA... WITH A LESSER CHANCE AT
RDU/RWI AND A VERY LOW CHANCE AT GSO/INT. ANY SHOWERS/STORMS IN THE
SOUTHEAST PORTION OF CENTRAL NC WILL DISSIPATE BY 03Z.
LOOKING BEYOND 06Z MONDAY (LATE TONIGHT)... IFR FOG IS POSSIBLE VERY
LATE TONIGHT INTO MONDAY MORNING AT ALL SITES AS HIGH HUMIDITY AND
LIGHT WINDS NEAR THE WEAKENING STALLED FRONT FACILITATE FOG
DEVELOPMENT. SCATTERED STORMS ARE ANTICIPATED MAINLY AT RDU/RWI/FAY
MONDAY AFTERNOON INTO EVENING. MORE MVFR/IFR FOG COULD OCCUR EARLY
TUESDAY MORNING. GREATER COVERAGE OF STORMS IS EXPECTED TUESDAY
AFTERNOON INTO THE NIGHT WITH LOCALLY GUSTY WINDS AND LOW CIGS/VSBY
IN/NEAR STORMS. THE OVERALL PATTERN WEAKENS AND BECOMES MORE
ILL-DEFINED MID-LATE WEEK. WHILE TYPICAL SCATTERED LATE DAY STORMS
ARE POSSIBLE AT ALL SITES WEDNESDAY/THURSDAY... DETAILS CANNOT BE
DETERMINED AT THIS TIME... BUT THE RISK OF MORNING FOG SHOULD BE
LOWER IN THIS TIME FRAME. -GIH
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 AM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY TOWARD THE SOUTHEAST THROUGH THE AREA
TODAY... BEFORE STALLING OUT OVER EASTERN VIRGINIA AND CENTRAL NORTH
CAROLINA THROUGH MONDAY. THE FRONT WILL WEAKEN AND DISSIPATE BY
MONDAY NIGHT. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE
SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY... RESULTING IN
UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 245 AM SUNDAY...
OVERALL PICTURE: THE LATEST SURFACE ANALYSIS SHOWS THE SURFACE FRONT
HAVING DRIFTED SOUTHEASTWARD IN THE LAST SEVERAL HOURS... TO A
POSITION ACROSS CENTRAL NC TO THE NC FOOTHILLS TO EXTREME NRN GA/AL.
IN THE MID LEVELS... WE REMAIN IN A PATTERN FEATURING A STRONG
ANTICYCLONE CENTERED OVER OK AND THE TX PANHANDLE AND TROUGHING IN
THE EAST. A WEAK PERTERBATION IS NOW PASSING THROUGH THE BASE OF THE
TROUGH THROUGH VA AND NRN NC... WITH A SECOND WEAKENING WAVE
DROPPING THROUGH KY AND A THIRD STRONGER WAVE OVER MN... ALSO
DROPPING TOWARD THE SE. WATER VAPOR IMAGERY AND BLENDED TOTAL PRECIP
WATER IMAGERY BOTH INDICATE DRY AIR HAVING MOVED INTO THE NRN/WRN
PORTIONS OF CENTRAL NC AND PW VALUES VERY CLOSE TO SEASONAL NORMALS
ACROSS THE REGION.
FOR TODAY/TONIGHT: PATCHY SHOWERS PERSIST OVER THE FAR SOUTHEAST
FRINGES OF THE FORECAST AREA... BUT OTHERWISE THE STRONG TO SEVERE
STORMS FROM LAST EVENING HAVE DIMINISHED... LEAVING JUST A COUPLE
HUNDRED J/KG OF SURFACE CAPE OVER THE EXTREME SOUTHERN SECTIONS AND
WEAK LAPSE RATES AREAWIDE. WITH WANING MOISTURE AND SUPPORT FOR
LIFT... WE SHOULD SEE A CONTINUE DISSOLUTION OF WHAT LITTLE PRECIP
IS OUT THERE BY DAWN. THE DEPARTING WEAK WAVE... THE INCOMING DRIER
AIR THROUGH THE COLUMN AS EXHIBITED ON GFS FORECAST SOUNDINGS AS
WELL AS UPSTREAM OBSERVED SOUNDINGS... AND THE EXITING UPPER
DIVERGENCE AS THE RIGHT ENTRANCE REGION OF THE JET ORIENTED ALONG
THE NORTHEAST COAST MOVES OFFSHORE SHOULD ALL WORK IN CONCERT TO
INHIBIT CONVECTION THROUGH THIS MORNING. WE SHOULD SEE ANOTHER
INLAND-TRACKING SEA BREEZE DEVELOP BY MIDDAY... PROVIDED THAT THE
CURRENT EXPANSE OF MID AND HIGH CLOUDS OVER THE COASTAL PLAIN AND
COASTAL AREA THINS OUT SUFFICIENTLY. IF IT DOES... WE SHOULD SEE
LIFT FORCED ALONG THE SEA BREEZE IN CONJUNCTION WITH DAYTIME HEATING
AND MOIST NEAR-SURFACE AIR TO GENERATE SHOWERS AND STORMS OVER THE
SOUTHEASTERN FORECAST AREA BY EARLY AFTERNOON. THE NEAR TO SLIGHTLY
BELOW NORMAL PW VALUES OVER THE NRN/WRN FORECAST AREA SHOULD LIMIT
INLAND PENETRATION OF ANY SUCH SEA BREEZE CONVECTION... AND
LINGERING SUBSIDENCE IN THE WAKE OF THE WEAK WAVE MAY FURTHER HINDER
STORM DEVELOPMENT. AS SUCH... HAVE CONFINED SCATTERED STORMS TO JUST
THE SOUTHEASTERN FORECAST AREA WITH NO BETTER THAN ISOLATED
SPREADING INTO THE ERN PIEDMONT AND WRN SANDHILLS LATER IN THE
AFTERNOON AS SHOWN BY THE SPC CONVECTION-ALLOWING 4-KM WRF MODEL...
BEFORE LOSS OF HEATING LEADS TO GRADUAL DISSIPATION OF CONVECTION
THROUGH THE MID TO LATE EVENING. INSTABILITY SHOULD BE MARGINAL AT
BEST WITH MLCAPE UNDER 500 J/KG OVER ALL BUT THE FAR SRN/ERN
COUNTIES... AND POOR DEEP-LAYER SHEAR WILL CUT BACK ON STORM
DEVELOPMENT... STRENGTH... AND ORGANIZATION AS WELL. THICKNESSES
THIS MORNING ARE EXPECTED TO BE SIMILAR TO YESTERDAY`S BUT NOT
RISING QUITE AS MUCH DURING THE DAY DUE TO SLIGHT COOLING AT 850 MB.
FACTORING THIS IN... EXPECT HIGHS OF 91-96... JUST A SHADE UNDER
SATURDAY`S HIGHS. WILL FOLLOW PERSISTENCE WITH LOWS... 68-74.
FORECAST SOUNDINGS AND STATISTICAL GUIDANCE ALONG WITH THE OVERALL
PATTERN ALL FAVOR FOG DEVELOPMENT LATE TONIGHT. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN IN THIS PERIOD WILL BE CHARACTERIZED BY
TROUGHING ALOFT OVER THE MID-ATLANTIC/CAROLINAS...ON THE EASTERN
PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL CONUS.
GIVEN TROUGHING ALOFT IN THE PRESENCE OF A SEASONABLY MOIST/UNSTABLE
AIRMASS...EXPECT ABOVE-NORMAL CHANCES FOR SHOWERS AND STORMS...
PRIMARILY DURING THE AFTERNOON/EVENING HOURS. SMALL AMPLITUDE
DISTURBANCES EMBEDDED WITHIN CYCLONIC FLOW ALOFT MON/TUE AND
INCREASINGLY NW FLOW ALOFT TUE NIGHT WILL ALLOW ISOLD/SCT CONVECTION
TO REMAIN POSSIBLE DURING THE OVERNIGHT HOURS...THOUGH THIS WILL
HIGHLY DEPEND ON THE EVOLUTION OF THE AFOREMENTIONED DISTURBANCES
AND THE EXTENT TO WHICH CONVECTIVE OVERTURNING OCCURS DURING THE
LATE AFTERNOON AND EVENING HOURS. WILL INDICATE 40-60% CHANCES FOR
SHOWERS/STORMS ON MONDAY WHEN MORE PRONOUNCED CYCLONIC FLOW ALOFT
WILL BE PRESENT...40-50% ON TUE...WITH CHANCES DECREASING TO 20%
AFTER MIDNIGHT. HIGHS ON BOTH MON/TUE SHOULD BE NEAR NORMAL IN THE
UPPER 80S/LOWER 90S) BASED ON 1000-850 MB THICKNESSES IN VICINITY OF
1415 METERS. LOWS ALSO SHOULD BE NEAR NORMAL...69-72F. THE PRIMARY
UNCERTAINTY WITH TEMPERATURES WILL BE THE TIMING/LOCATION OF
CONVECTION...AND CLOUD COVER ASSOCIATED WITH CONVECTION OR THE
REMNANTS THEREOF. A THREAT FOR ISOLD SEVERE THUNDERSTORMS CAPABLE OF
PRODUCING DAMAGING WINDS WILL REMAIN PRESENT DURING THE MID/LATE
AFTERNOON AND EVENING HOURS ON BOTH MONDAY AND TUESDAY. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN OVER THE CAROLINAS AND MID-ATLANTIC WED-SAT
WILL BE CHARACTERIZED INITIALLY (WED/THU) BY NW FLOW ALOFT...
TRANSITIONING (FRI/SAT) TO BROAD CYCLONIC FLOW ALOFT ON THE EASTERN
PERIPHERY OF A WEAKENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS.
PRECIPITATION CHANCES...I.E. THE TIMING/LOCATION/COVERAGE OF
CONVECTION...WILL BE HIGHLY DEPENDENT ON THE EVOLUTION OF SMALL
AMPLITUDE DISTURBANCES PROGRESSING SOUTHEAST FROM THE UPPER
MIDWEST/CENTRAL MS RIVER VALLEY INTO THE MID-ATLANTIC AND CAROLINAS.
DUE TO NW/CYCLONIC FLOW ALOFT IN THE PRESENCE OF A SEASONABLY
MOIST/UNSTABLE AIRMASS...WILL INDICATE CHANCES FOR SHOWERS/STORMS
SLIGHTLY ABOVE CLIMATOLOGY IN THE 30-40% RANGE...WITH A SLIGHT
CHANCE (20%) PERSISTING DURING THE OVERNIGHT HOURS. TEMPERATURES
WILL PRIMARILY DEPEND ON THE EVOLUTION OF CONVECTION AND ASSOCIATED
CLOUD COVER...WITH 1000-850 MB THICKNESSES SUGGESTING HIGHS AND LOWS
NEAR NORMAL...IN THE UPPER 80S TO LOWER 90S AND UPPER 60S TO LOWER
70S EACH DAY. -VINCENT
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO LAST FOR A FEW MORE HOURS OVERNIGHT
BEFORE THEY GIVE WAY TO MVFR VSBYS AS PATCHY LIGHT FOG DEVELOPS NEAR
RDU/RWI/FAY... LOCATIONS THAT RECEIVED A SOAKING RAIN FROM
THUNDERSTORMS LAST EVENING. BUT THE CONSIDERABLE MID AND HIGH CLOUDS
AT THESE SITES SHOULD INHIBIT RADIATIONAL COOLING AND BOTH DELAY
DEVELOPMENT AND LIMIT DENSITY OF FOG. RDU SHOULD SEE THE BEST CHANCE
OF SEVERAL HOURS OF MVFR FOG -- POSSIBLY DROPPING TO IFR -- GIVEN
THE COMBINATION OF PLENTY OF RAIN... LIGHT WINDS... AND AN EARLY
CLEARING OF CONVECTIVE DEBRIS MID AND HIGH CLOUDS. SURE ENOUGH...
THE LATEST HRRR EXPERIMENTAL AVIATION MODEL OUTPUT PLACES A PATCH OF
LOW VSBY NEAR RDU TOWARD MORNING. AT GSO/INT... ANY FOG IS EXPECTED
TO BE MORE THIN AND SHORT-LIVED AS THESE TWO SITES RECEIVED ONLY
BRIEF LIGHT RAIN NEAR THE TERMINALS... AND DRIER AIR IS SLOWLY
WORKING INTO THE TRIAD AREA FROM THE NORTHWEST. ANY FOG WILL LIFT
AND MIX OUT WITH HEATING BY 13Z-14Z. VFR CIGS ARE EXPECTED TO FORM
AT ALL SITES AFTER 16Z... WITH MORE EXPANSIVE CLOUD COVER AT
RDU/RWI/FAY. A FEW STORMS ARE EXPECTED NEAR FAY AFTER 17Z... EAST OF
A WEAKENING FRONT STALLED ACROSS THE AREA... WITH A LESSER CHANCE AT
RDU/RWI AND A VERY LOW CHANCE AT GSO/INT. ANY SHOWERS/STORMS IN THE
SOUTHEAST PORTION OF CENTRAL NC WILL DISSIPATE BY 03Z.
LOOKING BEYOND 06Z MONDAY (LATE TONIGHT)... IFR FOG IS POSSIBLE VERY
LATE TONIGHT INTO MONDAY MORNING AT ALL SITES AS HIGH HUMIDITY AND
LIGHT WINDS NEAR THE WEAKENING STALLED FRONT FACILITATE FOG
DEVELOPMENT. SCATTERED STORMS ARE ANTICIPATED MAINLY AT RDU/RWI/FAY
MONDAY AFTERNOON INTO EVENING. MORE MVFR/IFR FOG COULD OCCUR EARLY
TUESDAY MORNING. GREATER COVERAGE OF STORMS IS EXPECTED TUESDAY
AFTERNOON INTO THE NIGHT WITH LOCALLY GUSTY WINDS AND LOW CIGS/VSBY
IN/NEAR STORMS. THE OVERALL PATTERN WEAKENS AND BECOMES MORE
ILL-DEFINED MID-LATE WEEK. WHILE TYPICAL SCATTERED LATE DAY STORMS
ARE POSSIBLE AT ALL SITES WEDNESDAY/THURSDAY... DETAILS CANNOT BE
DETERMINED AT THIS TIME... BUT THE RISK OF MORNING FOG SHOULD BE
LOWER IN THIS TIME FRAME. -GIH
&&
.EQUIPMENT...
KRAX... THE WSR-88D RADAR LOCATED NEAR CLAYTON NC AND COVERING MUCH
OF CENTRAL NC... HAS EXPERIENCED A MECHANICAL FAILURE AND WILL
LIKELY BE DOWN THROUGH AT LEAST MIDDAY TODAY. TECHNICIANS WILL WORK
ON REPAIRS EARLY THIS MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 AM EDT SAT JUL 28 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE SLOWLY TOWARD THE SOUTHEAST THROUGH THE AREA
TODAY... BEFORE STALLING OUT OVER EASTERN VIRGINIA AND CENTRAL NORTH
CAROLINA THROUGH MONDAY. THE FRONT WILL WEAKEN AND DISSIPATE BY
MONDAY NIGHT. A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE
SOUTHEASTWARD THROUGH THE REGION THROUGH TUESDAY... RESULTING IN
UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
AS OF 958 PM SATURDAY...
SEVERE THUNDERSTORMS ARE WINDING DOWN AS THEY MOVE EAST THROUGH THE
SOUTHERN PINES... RALEIGH... ROCKY MOUNT AND ROANOKE RAPIDS AREA. WE
WILL LET THE WATCH EXPIRE AS THIS ACTIVITY WILL NOT REACH THE
ORIGINAL WATCH AREA DUE TO A STABLE BOUNDARY LAYER IN THE SE.
HOWEVER... ISOLATED SEVERE REPORTS MAY STILL OCCUR FROM SMITHFIELD
TO TARBORO IN THE NEXT HOUR OR TWO BEFORE THE LINE DIES OFF.
OTHERWISE... WILL REDUCE POP TO 20 AFTER MIDNIGHT.
UPDATES OUT SHORTLY. -BADGETT
ON SUNDAY THE BASE OF THE UPPER LEVEL TROUGH WILL PARK SOMEWHERE
IN THE VICINITY OF CENTRAL NORTH CAROLINA. DEPENDING ON POSITIONING
COULD DETERMINE HOW FAR TO THE NORTH AND WEST CONVECTION WILL
PROPAGATE SUNDAY AFTERNOON. REGARDLESS...THE THREAT FOR
CONVECTION...PROBABLY EAST OF HIGHWAY 1...IS CERTAINLY THERE AS
HIGHER DEWPOINTS AND MOIST SOUTHWESTERLY FLOW WILL AID THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS AFTER 18Z. AS OPPOSED TO
SATURDAY...DYNAMIC TROPOPAUSE MAPS SHOW A LACK OF UPSTREAM IMPULSES
TO AID THE DEVELOPMENT AND SUSTAINABILITY OF CONVECTION. THE SEA
BREEZE BOUNDARY WILL LIKELY BE A BIGGER PLAYER SUNDAY AFTERNOON IN
NOT ONLY INITIALIZING CONVECTION BUT HELPING IT TO SPREAD NORTH AND
WEST ACROSS THE EASTERN HALF OF THE CWA. LOW LEVEL LAPSE RATES WILL
BE VERY GOOD BUT THE MID-LEVEL LAPSE RATES WILL BE MORE MARGINAL.
SHEAR WILL BE REDUCED...THEREFORE FACTORS COMING TOGETHER TO SUPPORT
A MORE PULSE LIKE ENVIRONMENT AS OPPOSED TO THE BIT MORE LINEAR
STRUCTURES WE HAVE BEEN SEEING OVER THE PAST WEEK. HIGH TEMPERATURES
WILL TOP OUT IN THE LOW TO MID 90S WITH LOWS IN THE UPPER 60S TO LOW
70S. ANY FOG OR STRATUS THAT WOULD OCCUR SUNDAY NIGHT INTO MONDAY
SHOULD BE CONFINED TO EASTERN SITES...AHEAD OF THE TROUGH AXIS.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN IN THIS PERIOD WILL BE CHARACTERIZED BY
TROUGHING ALOFT OVER THE MID-ATLANTIC/CAROLINAS...ON THE EASTERN
PERIPHERY OF AN UPPER LEVEL RIDGE CENTERED OVER THE CENTRAL CONUS.
GIVEN TROUGHING ALOFT IN THE PRESENCE OF A SEASONABLY MOIST/UNSTABLE
AIRMASS...EXPECT ABOVE-NORMAL CHANCES FOR SHOWERS AND STORMS...
PRIMARILY DURING THE AFTERNOON/EVENING HOURS. SMALL AMPLITUDE
DISTURBANCES EMBEDDED WITHIN CYCLONIC FLOW ALOFT MON/TUE AND
INCREASINGLY NW FLOW ALOFT TUE NIGHT WILL ALLOW ISOLD/SCT CONVECTION
TO REMAIN POSSIBLE DURING THE OVERNIGHT HOURS...THOUGH THIS WILL
HIGHLY DEPEND ON THE EVOLUTION OF THE AFOREMENTIONED DISTURBANCES
AND THE EXTENT TO WHICH CONVECTIVE OVERTURNING OCCURS DURING THE
LATE AFTERNOON AND EVENING HOURS. WILL INDICATE 40-60% CHANCES FOR
SHOWERS/STORMS ON MONDAY WHEN MORE PRONOUNCED CYCLONIC FLOW ALOFT
WILL BE PRESENT...40-50% ON TUE...WITH CHANCES DECREASING TO 20%
AFTER MIDNIGHT. HIGHS ON BOTH MON/TUE SHOULD BE NEAR NORMAL IN THE
UPPER 80S/LOWER 90S) BASED ON 1000-850 MB THICKNESSES IN VICINITY OF
1415 METERS. LOWS ALSO SHOULD BE NEAR NORMAL...69-72F. THE PRIMARY
UNCERTAINTY WITH TEMPERATURES WILL BE THE TIMING/LOCATION OF
CONVECTION...AND CLOUD COVER ASSOCIATED WITH CONVECTION OR THE
REMNANTS THEREOF. A THREAT FOR ISOLD SEVERE THUNDERSTORMS CAPABLE OF
PRODUCING DAMAGING WINDS WILL REMAIN PRESENT DURING THE MID/LATE
AFTERNOON AND EVENING HOURS ON BOTH MONDAY AND TUESDAY. -VINCENT
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 230 PM SATURDAY...
THE SYNOPTIC PATTERN OVER THE CAROLINAS AND MID-ATLANTIC WED-SAT
WILL BE CHARACTERIZED INITIALLY (WED/THU) BY NW FLOW ALOFT...
TRANSITIONING (FRI/SAT) TO BROAD CYCLONIC FLOW ALOFT ON THE EASTERN
PERIPHERY OF A WEAKENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS.
PRECIPITATION CHANCES...I.E. THE TIMING/LOCATION/COVERAGE OF
CONVECTION...WILL BE HIGHLY DEPENDENT ON THE EVOLUTION OF SMALL
AMPLITUDE DISTURBANCES PROGRESSING SOUTHEAST FROM THE UPPER
MIDWEST/CENTRAL MS RIVER VALLEY INTO THE MID-ATLANTIC AND CAROLINAS.
DUE TO NW/CYCLONIC FLOW ALOFT IN THE PRESENCE OF A SEASONABLY
MOIST/UNSTABLE AIRMASS...WILL INDICATE CHANCES FOR SHOWERS/STORMS
SLIGHTLY ABOVE CLIMATOLOGY IN THE 30-40% RANGE...WITH A SLIGHT
CHANCE (20%) PERSISTING DURING THE OVERNIGHT HOURS. TEMPERATURES
WILL PRIMARILY DEPEND ON THE EVOLUTION OF CONVECTION AND ASSOCIATED
CLOUD COVER...WITH 1000-850 MB THICKNESSES SUGGESTING HIGHS AND LOWS
NEAR NORMAL...IN THE UPPER 80S TO LOWER 90S AND UPPER 60S TO LOWER
70S EACH DAY. -VINCENT
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 120 AM SUNDAY...
VFR CONDITIONS ARE EXPECTED TO LAST FOR A FEW MORE HOURS OVERNIGHT
BEFORE THEY GIVE WAY TO MVFR VSBYS AS PATCHY LIGHT FOG DEVELOPS NEAR
RDU/RWI/FAY... LOCATIONS THAT RECEIVED A SOAKING RAIN FROM
THUNDERSTORMS LAST EVENING. BUT THE CONSIDERABLE MID AND HIGH CLOUDS
AT THESE SITES SHOULD INHIBIT RADIATIONAL COOLING AND BOTH DELAY
DEVELOPMENT AND LIMIT DENSITY OF FOG. RDU SHOULD SEE THE BEST CHANCE
OF SEVERAL HOURS OF MVFR FOG -- POSSIBLY DROPPING TO IFR -- GIVEN
THE COMBINATION OF PLENTY OF RAIN... LIGHT WINDS... AND AN EARLY
CLEARING OF CONVECTIVE DEBRIS MID AND HIGH CLOUDS. SURE ENOUGH...
THE LATEST HRRR EXPERIMENTAL AVIATION MODEL OUTPUT PLACES A PATCH OF
LOW VSBY NEAR RDU TOWARD MORNING. AT GSO/INT... ANY FOG IS EXPECTED
TO BE MORE THIN AND SHORT-LIVED AS THESE TWO SITES RECEIVED ONLY
BRIEF LIGHT RAIN NEAR THE TERMINALS... AND DRIER AIR IS SLOWLY
WORKING INTO THE TRIAD AREA FROM THE NORTHWEST. ANY FOG WILL LIFT
AND MIX OUT WITH HEATING BY 13Z-14Z. VFR CIGS ARE EXPECTED TO FORM
AT ALL SITES AFTER 16Z... WITH MORE EXPANSIVE CLOUD COVER AT
RDU/RWI/FAY. A FEW STORMS ARE EXPECTED NEAR FAY AFTER 17Z... EAST OF
A WEAKENING FRONT STALLED ACROSS THE AREA... WITH A LESSER CHANCE AT
RDU/RWI AND A VERY LOW CHANCE AT GSO/INT. ANY SHOWERS/STORMS IN THE
SOUTHEAST PORTION OF CENTRAL NC WILL DISSIPATE BY 03Z.
LOOKING BEYOND 06Z MONDAY (LATE TONIGHT)... IFR FOG IS POSSIBLE VERY
LATE TONIGHT INTO MONDAY MORNING AT ALL SITES AS HIGH HUMIDITY AND
LIGHT WINDS NEAR THE WEAKENING STALLED FRONT FACILITATE FOG
DEVELOPMENT. SCATTERED STORMS ARE ANTICIPATED MAINLY AT RDU/RWI/FAY
MONDAY AFTERNOON INTO EVENING. MORE MVFR/IFR FOG COULD OCCUR EARLY
TUESDAY MORNING. GREATER COVERAGE OF STORMS IS EXPECTED TUESDAY
AFTERNOON INTO THE NIGHT WITH LOCALLY GUSTY WINDS AND LOW CIGS/VSBY
IN/NEAR STORMS. THE OVERALL PATTERN WEAKENS AND BECOMES MORE
ILL-DEFINED MID-LATE WEEK. WHILE TYPICAL SCATTERED LATE DAY STORMS
ARE POSSIBLE AT ALL SITES WEDNESDAY/THURSDAY... DETAILS CANNOT BE
DETERMINED AT THIS TIME... BUT THE RISK OF MORNING FOG SHOULD BE
LOWER IN THIS TIME FRAME. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...BADGETT/ELLIS
SHORT TERM...VINCENT
LONG TERM...VINCENT
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
851 PM CDT MON JUL 30 2012
.DISCUSSION...
EVENING UPDATE WILL FOCUS ON SKY AND TEMP TRENDS. LATEST VIS SHOT
PRIOR TO SUNSET SHOWING MOST CU HAS DISSIPATED WITH SOME REMAINING
EAST OF THE VALLEY. WILL DROP SKY TO NEAR ZERO. TEMP CURVE
GENERALLY LOOKS ON TRACK BUT MADE SOME ADJUSTMENTS TO HOURLY TEMP
GRIDS WITH LATEST RUC GUIDANCE. HIGH PRESSURE WILL MOVE OVER THE
EASTERN ZONES TONIGHT AND SHOULD SEE CLEAR SKIES WITH TEMPS
NEARING DEW POINTS BUT WITH GENERALLY NORTHERLY FLOW FOR THE NEXT
SEVERAL HOURS...NOT TOO CONFIDENT IN ANY MENTION OF FOG. WILL
MONITOR OVER NEXT COUPLE HOURS AND SEND SECOND UPDATE IF NEEDED.
&&
.AVIATION...
VFR AS HIGH PRESSURE MOVES OVER THE AREA. CALMEST WINDS WILL BE
OVER BJI AND TVF. WILL NEED TO MONITOR FOR FOG POTENTIAL BUT AT
THE CURRENT TIME DO NOT THINK DEW POINT DEPRESSION WILL BE LOW
ENOUGH FOR FOG DEVELOPMENT AT ANY GIVEN SITE.
&&
.PREV DISCUSSION... /ISSUED 307 PM CDT MON JUL 30 2012/
SHORT TERM (TONIGHT THROUGH THURS)...
MODELS IN OVERALL FAIR AGREEMENT. HAVE STUCK CLOSE TO THE GFS TIMING
OVERALL... AND WITH NAM/ECMWF BLEND ON TEMPS/PRECIP AMOUNTS.
FAIR SKIES AND LIGHT WINDS EXPECTED OVERNIGHT AS SFC HIGH PRESSURE
RIDGE TRANSITS THE AREA... AND WITH SUBSIDENT HIGH PRESSURE BUILDING
IN ALOFT THE AREA SHOULD BE FREE OF MID TO UPPER LEVEL CLOUDS...
ALLOWING FOR A PLENTY OF WAXING MOONLIGHT.
TUES/WED... SOUTHERLY WINDS WILL DEVELOP THROUGH THE DAY AS LOW
PRESSURE PUSHES INTO THE WESTERN DKTAS. WIDELY SCATTERED SHOWERS ARE
POSSIBLE LATE TUES INTO WED AM AS THAT LOW PRESSURE SYSTEM QUICKLY
PUSHES THROUGH. WINDS SHOULD SWAP NORTHWESTERLY THROUGH WED AM AS
THAT SYSTEM PASSES.
WED PM INTO THURS... NEXT WEAK SYSTEM DUE THROUGH DURING THE LATE
EVENING AND OVERNIGHT HOURS BRINGING A BRIEF WIND SHIFT AND SPOTTY
SHOWER ACTIVITY. OVERALL TEMPS REMAIN ABOVE SEASONAL NORMALS WHILE
PRECIP AMOUNTS REMAINS BELOW SEASONAL NORMALS DURING THIS MIDWEEK
PERIOD.
LONG TERM (THURS NITE THROUGH SUN)...
DESPITE SOME MINOR DIFFERENCES...AN INSPECTION OF OUR MAJOR LONG
TERM GUIDANCE PRODUCTS (GFS/ECMWF/GEM) REVEALS A CLOSED LOW
BARRELING TOWARD THE NORTHERN PLAINS FROM THE CANADIAN ROCKIES AS
THE EXTENDED PERIOD GETS UNDERWAY.
POPS ARE IN THE CHANCE TO LIKELY CATEGORY FOR THE MAJORITY OF FRIDAY
AND SATURDAY AS THIS SYSTEM ROLLS THROUGH WITH ITS SHOWERS AND
THUNDERSTORMS. H850 TEMPS DROP TO TYPICAL H700 NUMBERS THIS TIME OF
YEAR BY LATE SATURDAY INTO SUNDAY WHERE WE HAVE LIMITED HIGH
TEMPERATURES TO THE 70S. NOT TOO KEEN ON POPS FOR MONDAY ABSENT ANY
TANGIBLE WEATHER MAKERS...BUT LEFT IN SLIGHT CHANCES AT THIS TIME.
AVIATION...
CELLULAR CUMULUS HUMILIS TO DISSIPATE TOWARD SUNSET...LEAVING HIGH
PRESSURE AND VARIABLE WINDS FOR THE OVERNIGHT. VFR CONDITIONS TO
PREVAIL THROUGH TUESDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SPEICHER
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION SECTION
NWS BISMARCK ND
325 PM CDT SUN JUL 29 2012
.SHORT TERM...NOW THROUGH MONDAY NIGHT...
THE FIRST OF WHAT COULD TURN OUT TO BE SEVERAL THUNDERSTORMS
FORMED NEAR BOWMAN THIS AFTERNOON...WHICH IS CONSISTENT WITH THE
16 UTC HRRR AND 12 UTC GFS/NAM...THOUGH A LITTLE WEST OF EXPECTED
INITIATION. THE 12 UTC ECMWF HAS MOVED LIGHT PRECIPITATION
WESTWARD COMPARED TO ITS 00 UTC RUN. FOR THIS REASON...GRIDDED
FORECASTS CONTINUE TO REFLECT HIGHER PRECIPITATION CHANCES AS
FORECAST BY THE 09 UTC SREF. WITH RESPECT TO SEVERITY...SPC HAS
OUTLINED A SLIGHT RISK MAINLY OVER THE DEVILS LAKE BASIN AND
EAST. CONVECTIVE TRENDS SEEM TO JUSTIFY THIS AS THE STORM NEAR
BOWMAN HAS REMAINED NON-SEVERE FOR ALMOST AN HOUR.
THEREAFTER...LOOK FOR PERSISTENCE AS SEVERAL MIDDLE LEVEL
SHORTWAVES MOVE TOWARD THE DAKOTAS. AT PRESENT...MONDAY LOOKS TO
BE DRY...WITH THE NEXT MAIN SYSTEM MOVING INTO THE AREA MONDAY
NIGHT. MODELS ARE A BIT MIXED WITH THE 12 UTC ECMWF DRY AND THE 12
UTC NAM SPOTTY. THE 12 UTC GFS AND 15 UTC SREF MEAN ARE AMONG THE
WET SOLUTIONS...SO MAINTAINED ONLY ISOLATED/SCATTERED ACROSS THE
WEST FOR NOW.
TEMPERATURES WILL REMAIN ABOVE AVERAGE AS THE SUBTROPICAL RIDGE
OVER THE CENTRAL U.S. SHOWS NO SIGN OF WEAKENING.
.LONG TERM...TUESDAY THROUGH SUNDAY...
STRONG RIDGING REMAINS OVER THE PLAINS AND ROCKIES AND EXTENDS WELL
INTO THE CANADIAN PRAIRIE PROVINCES. WEAK SHORTWAVES TOPPING RIDGE
AND DRAGGING WEAK FRONTS ACROSS THE NORTHERN PLAINS WILL TRIGGER
OUTBREAKS OF CONVECTION OVER WESTERN AND CENTRAL NORTH DAKOTA.
THE FIRST SYSTEM ARRIVES IN WESTERN DAKOTAS LATE MONDAY
NIGHT/TUESDAY MORNING AND MOVES ACROSS THE STATE DURING TUESDAY
AFTERNOON AND EVENING.
THE MODELS DIFFER QUITE A BIT ON TIMING WEDNESDAY/THURSDAY BUT WILL
KEEP A MENTION OF PRECIPITATION AT THIS TIME.
BY THURSDAY NIGHT/FRIDAY STRONGER SYSTEM IN NORTHERN FLOW WILL PUSH
STRONG FRONTAL SYSTEM ACROSS THE REGION. THE RIDGE REMAINS OVER THE
SOUTHERN PLAINS BUT IS FLATTENED CONSIDERABLE ALONG THE CANADIAN
BORDER WITH FASTER FLOW. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL
EARLY IN THE EXTENDED THEN DROP TO SLIGHTLY BELOW NORMAL BY NEXT
WEEKEND.
&&
.AVIATION...
THE VCTY OF THE FRONTAL BOUNDARY POSITION WILL BE THE LIKELY AREA
OF TSTM INITIATION THIS AFTN. AT 3 PM CDT...THE POSITION OF THE SFC
FRONT HAD MOVED ONLY SLIGHTLY EASTWARD IN THE PAST COUPLE
OF HOURS...EXTENDING FROM NEAR BOTTINEAU TO BETWEEN KMOT AND
KN60...TO NEAR KBIS AND KHEI. THE BOUNDARY SHOULD MOVE EASTWARD
SLOWLY THIS AFTN AND EVENING. TSTMS HAD DEVELOPED NEAR KHEI ALONG
THE BOUNDARY. KMOT AND KBIS HAVE VCTS BEGINNING AROUND 21Z WITH
THREAT ENDING BY AROUND 00Z...BUT MAY AMEND TO SKC IN THE NEXT HOUR
OR SO IF THREAT OF TSTMS TREND REMAINS TO THE SOUTH AND EAST. KJMS
TAF SITE HAS A CHANCE FOR THUNDER FROM 21Z-03Z. IT APPEARS THAT KISN
AND KDIK MAY BE TOO FAR WEST OF THE BOUNDARY FOR FORECASTING TSTM
DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION....JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
300 PM CDT SUN JUL 29 2012
.SHORT TERM...NOW THROUGH MONDAY NIGHT...
THE FIRST OF WHAT COULD TURN OUT TO BE SEVERAL THUNDERSTORMS
FORMED NEAR BOWMAN THIS AFTERNOON...WHICH IS CONSISTENT WITH THE
16 UTC HRRR AND 12 UTC GFS/NAM...THOUGH A LITTLE WEST OF EXPECTED
INITIATION. THE 12 UTC ECMWF HAS MOVED LIGHT PRECIPITATION
WESTWARD COMPARED TO ITS 00 UTC RUN. FOR THIS REASON...GRIDDED
FORECASTS CONTINUE TO REFLECT HIGHER PRECIPITATION CHANCES AS
FORECAST BY THE 09 UTC SREF. WITH RESPECT TO SEVERITY...SPC HAS
OUTLINED A SLIGHT RISK MAINLY OVER THE DEVILS LAKE BASIN AND
EAST. CONVECTIVE TRENDS SEEM TO JUSTIFY THIS AS THE STORM NEAR
BOWMAN HAS REMAINED NON-SEVERE FOR ALMOST AN HOUR.
THEREAFTER...LOOK FOR PERSISTENCE AS SEVERAL MIDDLE LEVEL
SHORTWAVES MOVE TOWARD THE DAKOTAS. AT PRESENT...MONDAY LOOKS TO
BE DRY...WITH THE NEXT MAIN SYSTEM MOVING INTO THE AREA MONDAY
NIGHT. MODELS ARE A BIT MIXED WITH THE 12 UTC ECMWF DRY AND THE 12
UTC NAM SPOTTY. THE 12 UTC GFS AND 15 UTC SREF MEAN ARE AMONG THE
WET SOLUTIONS...SO MAINTAINED ONLY ISOLATED/SCATTERED ACROSS THE
WEST FOR NOW.
TEMPERATURES WILL REMAIN ABOVE AVERAGE AS THE SUBTROPICAL RIDGE
OVER THE CENTRAL U.S. SHOWS NO SIGN OF WEAKENING.
.LONG TERM...TUESDAY THROUGH SUNDAY...
STRONG RIDGING REMAINS OVER THE PLAINS AND ROCKIES AND EXTENDS WELL
INTO THE CANADIAN PRAIRIE PROVINCES. WEAK SHORTWAVES TOPPING RIDGE
AND DRAGGING WEAK FRONTS ACROSS THE NORTHERN PLAINS WILL TRIGGER
OUTBREAKS OF CONVECTION OVER WESTERN AND CENTRAL NORTH DAKOTA.
THE FIRST SYSTEM ARRIVES IN WESTERN DAKOTAS LATE MONDAY
NIGHT/TUESDAY MORNING AND MOVES ACROSS THE STATE DURING TUESDAY
AFTERNOON AND EVENING.
THE MODELS DIFFER QUITE A BIT ON TIMING WEDNESDAY/THURSDAY BUT WILL
KEEP A MENTION OF PRECIPITATION AT THIS TIME.
BY THURSDAY NIGHT/FRIDAY STRONGER SYSTEM IN NORTHERN FLOW WILL PUSH
STRONG FRONTAL SYSTEM ACROSS THE REGION. THE RIDGE REMAINS OVER THE
SOUTHERN PLAINS BUT IS FLATTENED CONSIDERABLE ALONG THE CANADIAN
BORDER WITH FASTER FLOW. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL
EARLY IN THE EXTENDED THEN DROP TO SLIGHTLY BELOW NORMAL BY NEXT
WEEKEND.
&&
.AVIATION...
THE VCTY OF THE FRONTAL BOUNDARY POSITION WILL BE THE LIKELY AREA
OF TSTM INITIATION THIS AFTN. AT 3 PM CDT...THE POSITION OF THE SFC
FRONT HAD REMAINED NEARLY STATIONARY IN THE PAST COUPLE OF
HOURS...EXTENDING FROM NEAR BOTTINEAU TO BETWEEN KMOT AND KN60...TO
NEAR KHEI. THE BOUNDARY SHOULD MOVE EASTWARD SLOWLY THIS AFTN AND
EVENING. TSTMS HAD DEVELOPED NEAR KHEI ALONG THE BOUNDARY. KMOT AND
KBIS HAVE VCTS BEGINNING AROUND 21Z WITH THREAT ENDING BY AROUND
00Z. KJMS TAF SITE HAS A CHANCE FOR THUNDER FROM 21Z-03Z. IT APPEARS
THAT KISN AND KDIK MAY BE TOO FAR WEST OF THE BOUNDARY FOR
FORECASTING TSTM DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SCHECK
LONG TERM/AVIATION....JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CDT SUN JUL 29 2012
.DISCUSSION...
THE LAST 3 RUNS OF THE HRRR INSIST ON RAPID DEVELOPMENT OF A
BOWING LINE STRUCTURE ALONG AND SOUTH OF THE I94 CORRIDOR THIS
MORNING...BUT CURRENT CONVECTIVE TRENDS DO NOT SUPPORT SUCH A
SCENARIO. SO...ONLY AESTHETIC CHANGES HAVE BEEN MADE TO THE
FORECAST THIS MORNING.
THE MAIN FORECAST PROBLEM TODAY WILL BE TIMING THE BARRAGE OF
MIDDLE LEVEL SHORTWAVES AIMED AT THE NORTHERN PLAINS...AND TRYING
TO DECIDE WHICH WILL PROVIDE SUFFICIENT BROAD SCALE LIFT TO RESULT
IN ORGANIZED SEVERE THUNDERSTORMS.
&&
.AVIATION...
SCT TO BKN MID LEVEL CLOUDS OVER TAF SITES. AREA OF LIGHT SHOWERS
AND VIRGA FROM NEAR KBIS MOVING EASTWARD MAY REACH KJMS BY AROUND 21-22Z.
SURFACE FRONTAL BOUNDARY TO BE ORIENTED FROM NEAR KDVL TO NEAR
KBIS/KDIK TO KHEI AROUND 18Z AND MAY BE THE FOCUS OF AFTERNOON TSTM
DEVELOPMENT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...SCHECK
AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1116 PM CDT SAT JUL 28 2012
.DISCUSSION...LATEST WATER VAPOR IMAGERY CONTINUES TO SHOW A
REPEATING PATTERN OF SHORTWAVES ROTATING FROM THE INTER-MOUNTAIN
WEST INTO NORTH DAKOTA. A SHORTWAVE TROUGH IN SOUTHERN ALBERTA WAS
SUPPRESSING HEIGHTS AS IT CONTINUES TO CIRCULATE/MOVE NORTHEAST
AND ALSO AIDING IN THUNDERSTORM DEVELOPMENT IN SOUTHERN CANADA.
MOISTURE/SHORTWAVE ENERGY ROTATING AROUND A STATIONARY UPPER
LEVEL HIGH CENTERED OVER NORTH TEXAS IN CONJUNCTION WITH THE
AFOREMENTIONED SHORTWAVES HAS BEEN PRODUCING A LINE OF
SHOWERS/THUNDERSTORMS OVER EASTERN MONTANA EARLY TONIGHT WITH
WIND GUSTS REPORTS AS HIGH AS 60 MPH EARLIER. WILL CONTINUE TO
MONITOR AS THIS LINE APPROACHES WESTERN NORTH DAKOTA...BUT THE
OVERALL TREND IS FOR WEAKENING. LOCAL RADAR WAS SHOWING ISOLATED
SHOWERS/THUNDERSTORMS DEVELOPING FROM NEAR MANDAREE TO VELVA AND
MOVING SOUTHEAST. HAVE EXPANDED THE ISOLATED POPS FURTHER SOUTH TO
ACCOUNT FOR THIS ACTIVITY FOR THE REST OF THE NIGHT.
OUR NEXT SHORTWAVE OF INTEREST IS SEEN IN THE SALMON/CHALLIS
MOUNTAINOUS REGION IN CENTRAL IDAHO. THIS IS FORECAST TO MOVE EAST
TONIGHT AND REACH CLOSE TO OUR WESTERN BORDER BY 12Z SUNDAY. THE
LATEST HRRR AND SREF...AND TO SOME EXTENT THE 00Z NAM DO SHOW
ANOTHER AREA OF PRECIPITATION ARRIVING IN OUR WESTERN ZONES BY
AROUND 09Z-10Z. THE HRRR COMPOSITE REFLECTIVITY SUGGESTS THIS
WOULD BE NON-SEVERE AND MAY CONTINUE FROM 10Z TO 14Z SUNDAY.
&&
.AVIATION...LOW PRESSURE IN EASTERN MONTANA WILL MOVE SLOWLY EAST
OVERNIGHT. THIS WILL BE THE FOCUS FOR MORE THUNDERSTORMS OVER WESTERN
AND NORTHERN NORTH DAKOTA...HOWEVER VFR CONDITIONS ARE EXPECTED AT
ALL TAF SITES. THE MAIN HAZARD THROUGH 12Z SUNDAY WILL BE WIDELY
SCATTERED THUNDERSTORMS AT KDIK/KISN/KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KS
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1025 AM EDT SUN JUL 29 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL CROSS THE AREA TODAY AND
MOVE TO THE EAST COAST MONDAY WHERE IT WILL BECOME NEARLY
STATIONARY. A WEAK COLD FRONT WILL SLOWLY CROSS THE AREA MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE OVER THE AREA TODAY. THE BIG QUESTION IS HOW MUCH
CUMULUS WILL DEVELOP. SOME PATCHY CLOUDS ACROSS THE REGION WILL
LIKELY EXPAND. THE DENSE FOG BURNED OFF QUICKLY OVER INLAND NW PA.
THE DAY WILL BE DRY EVEN THOUGH THE RUC MODEL AND THE HRRR IS
HINTING AT A FEW SHOWERS DEVELOPING. NO MAJOR CHANGES TO
TEMPERATURE FORECAST.
PREVIOUS DISCUSSION...
A FEW MID CLOUDS CONTINUE TO DEVELOP ACROSS EXTREME NE OH/NW PA
ON THE BACK EDGE OF THE UPPER TROUGH AND WILL PROBABLY DO SO
THROUGH MID MORNING. JUST COOL ENOUGH ALOFT FOR A FEW LAKE CLOUDS.
SCATTERED TO BROKEN CLOUDS HAVE BEEN MOST COMMON OFF THE WESTERN
BASIN THIS MORNING. THERE COULD ALSO BE SOME CLOUDS DEVELOP EARLY
THIS MORNING ALONG THE LAKESHORE DUE TO CONVERGENCE. A FEW OF
THESE LAKE CLOUDS WILL SPREAD INLAND THIS MORNING AND GRADUALLY
MIX AWAY AND TRANSITION TO A FEW FAIR WEATHER CUMULUS THIS
AFTERNOON. ALL THAT BEING SAID...WE SHOULD END UP WITH A NICE DAY
WITH PLENTY OF SUNSHINE AND RELATIVELY LOW HUMIDITY. HIGHS IN THE
LOWER/MID 80S EXCEPT A COUPLE OF DEGREES COOLER NEAR THE LAKE ERIE
LAKESHORE. ALSO MADE A FEW MINOR ADJUSTMENTS TO THE MORNING HOURLY
TEMPERATURES FOR THE EARLY MORNING UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
ANOTHER TROUGH ALOFT BEGINS TO DEVELOP OVER THE CENTRAL GREAT LAKES
AND OHIO VALLEY ON MONDAY. THE MODELS SEEM WAY TO AGGRESSIVE ON THE
CHANCE OF RAIN ON MONDAY. WHILE WE WILL GET CLOSER TO THE "RING OF
FIRE" JUST TO OUR WEST... IT SEEMS UNLIKELY GIVEN THE RELATIVELY
STABLE AND DRY AIR MASS AND THE NEARBY SURFACE HIGH PRESSURE THAT WE
WOULD SEE MUCH MORE THAN DEBRIS CLOUDS IN THE NORTHWEST FLOW ALOFT
AND A SHOWER OR SPRINKLE. A LOCAL SHOWER OR THUNDERSHOWER MIGHT POP
UP LATE IN THE DAY BUT AGAIN...THE COVERAGE SHOULD BE LIMITED. WILL
CONTINUE WITH A LOW PROBABILITY OF PRECIPITATION (20-30 PERCENT).
WILL TRIM BACK THE FORECAST TEMPERATURES A FEW DEGREES GIVEN THE
EXTRA CLOUDS AND THE WEAK WARM ADVECTION IN THE LIGHT FLOW.
THE NEXT COLD FRONT WILL APPROACH ON TUESDAY. THE LIGHT SOUTH FLOW
AHEAD OF THE FRONT WILL ENABLE THINGS TO BECOME MORE UNSTABLE. IT IS
NOT LIKE THE GULF WILL BE OPEN BUT DEWPOINTS WILL BEGIN TO RISE
THROUGH THE 60S AND IF WE SEE ENOUGH SUNSHINE THERE SHOULD BE A
SCATTERING OF THUNDERSTORMS. HIGHS WILL BE A FEW DEGREES WARMER
THAN MONDAY...IN THE MID/UPPER 80S.
I SUSPECT THE FRONT MAY BE LINGERING SOMEWHERE IN THE AREA ON
WEDNESDAY... ESPECIALLY NE OH/NW PA... GIVEN THE RISING HEIGHTS AND
LIGHT FLOW. KEPT A SMALL CHANCE OF SHOWERS AND THUNDERSTORMS...
MAINLY ACROSS NE OH/NW PA. HIGHS WILL DEPEND ON WHERE THE FRONT ENDS
UP AND HOW MUCH CLOUDS/SHOWERS OCCUR. STAYED CLOSE TO THE PREVIOUS
FORECAST WITH HIGHS GENERALLY IN THE LOWER/MID 80S.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
MODELS IN REASONABLE AGREEMENT ON THURSDAY WITH HIGH PRESSURE OVER
THE GREAT LAKES. MODELS BEGIN TO DIVERGE FRIDAY WITH GFS MOVING LOW
PRESSURE SYSTEM INTO THE UPPER LAKES FRIDAY OPENING CHANCE POPS OVER
THE AREA FRIDAY INTO SUNDAY. ECMWF ON THE OTHER HAD MUCH SLOWER
MOVING HIGH PRESSURE OUT AND HOLDING LOW WELL WEST OF THE AREA INTO
SATURDAY. FOR THIS FORECAST LEANED TOWARD THE SLOWER ECMWF AND
HOLDING CHANCE OF PRECIP BACK UNTIL FRIDAY NIGHT AND INTO SATURDAY.
CONFIDENCE IS LOW THIS FAR OUT SO WILL GO WITH LOW CHANCE POPS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
CURRENTLY MVFR BR WITH PATCHY IFR VIS MAINLY SOUTH OF YNG-FDY
LINE. CONDITIONS SHOULD IMPROVE TO VFR BY MID MORNING...AND
CONTINUE THROUGH REMAINDER OF FORECAST PERIOD.
THE 850 MB TEMPS ARE DOWN TO 14C. DO EXPECT SOME LAKE EFFECT
CLOUDS TO DEVELOP THIS AFTERNOON...CONFIDENCE LOW AS TO HOW
WIDESPREAD IT WILL BE.
.OUTLOOK...NON VFR CONDITIONS ARE POSSIBLE TUESDAY IN SHOWERS AND
THUNDERSTORMS.
&&
.MARINE...
HIGH PRESSURE CENTERED OVER MICHIGAN WILL SLIDE OVER THE LAKES TODAY
SO NORTH FLOW WILL BECOME MORE VARIABLE THIS AFTERNOON. HIGH SHIFTS
EAST OF THE LAKE ON MONDAY SETTING UP SOUTHERLY FLOW OVER THE LAKE.
A WEAK COLD FRONT WILL MOVE ACROSS THE LAKE TUESDAY NIGHT INTO
WEDNESDAY MORNING. THIS WILL SET UP A WEST TO NORTHWEST FLOW OVER
THE LAKE. EXPECT CHOPPY CONDITIONS TO DEVELOP BUT FOR NOW LOOKS
LIKE WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KIELTYKA/KOSARIK
SHORT TERM...KOSARIK
LONG TERM...DJB
AVIATION...DJB
MARINE...DJB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
358 PM EDT SUN JUL 29 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SHIFT EAST-NORTHEAST INTO NEW ENGLAND
TODAY...ALLOWING HIGH PRESSURE OVER THE LOWER GREAT LAKES TO
MOVE INTO CENTRAL PENNSYLVANIA THROUGH TONIGHT. ANOTHER UPPER
LEVEL TROUGH WILL MOVE EAST FROM THE OHIO VALLEY ON MONDAY AND
BECOME NEARLY STATIONARY OVER THE MID-ATLANTIC REGION. THIS
FEATURE WILL MAINTAIN AN UNSETTLED WEATHER PATTERN WITH SEVERAL
OPPORTUNITIES FOR RAIN THROUGH MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
18Z UPDATE...VIS SATL SHOWS CU FIELD HAS GENERALLY DECREASED IN
CVRG WITH MORE SUN THAN CLOUDS AT MOST LOCATIONS. RDR SHOWS
DEVELOPING SHOWERS OVR NRN SCHUYLKILL COUNTY EWD TO ABE VCNTY. THE
LATEST NEAR TERM MODEL GUID CONTINUES TO SHOW A MARGINAL/SLIGHT
INCREASE IN DIURNAL SHOWERS INTO THE MID AFTN WITH AN ISOLD TSTM
PSBL ACRS THE FAR ERN ZONES. RUC DATA ALONG WITH 16Z SATL DERIVED
TPW SHOW A LINGERING MSTR AXIS WITH PWATS BTWN 1-1.5 INCHES OVR
ERN PA. THEREFORE WILL MAINTAIN CHC POPS THRU THE LATE AFTN...WITH
ACTIVITY EXPECTED TO DISSIPATE WITH THE LOSS OF DAYTIME HEATING.
THE SHOWERS/ISOLD TSTMS MAY CONTAIN BRIEF HEAVY DOWNPOURS WITH A
GENERAL 360/15 STM MOTION.
THERE IS ALSO A LINE OF ENHANCED CU DOWNWIND OF LAKE ERIE ASSOC
WITH LAKE BREEZE FNT. INLAND DEWPTS QUICKLY DROP OFF INTO THE 50S
THEREFORE DO NOT EXPECT ISOLD SHOWERS TO REACH THE NW MTNS.
THE MID-UPPER TROUGH AND ASSOCD S/W ENERGY ALONG THE NRN MID-ATLC
- SRN NEW ENG COAST WILL CONTINUE TO LIFT NEWD INTO DOWNEAST MAINE
TONIGHT..ALLOWING SFC HIGH PRES TO OVERSPREAD CENTRAL PA FROM THE
LOWER GREAT LAKES. CLEAR/CALM CONDS AND NEAR TO SLIGHTLY BLW
NORMAL PWS WILL SUPPORT RELATIVELY COOL MINS RANGING FROM THE
LOW-MID 50S NORTH TO LOW-MID 60S SOUTH. SOME OF THE TYPICALLY
COLDER SPOTS IN THE NORTH MAY DIP INTO THE UPPER 40S. THE COOL
AIR...COMBINED WITH LIGHT WINDS AND RELATIVELY WARMER RIVER/STREAM
WATER WILL LIKELY RESULT IN PATCHY LATE NIGHT FOG IN THE DEEP
VALLEYS ACRS THE N-CENTRAL MTNS.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
HIGH PRES WILL SHIFT OFF THE NORTHEAST COAST ON MONDAY...ALLOWING
RETURN SOUTHERLY FLOW TO ADVECT HIGHER DEWPTS BACK INTO THE
REGION. LG SCALE FORCING AHEAD OF LOW AMPLITUDE H5 SHORTWAVE TROF
SWEEPING EWD THRU THE OHIO VALLEY...COMBINED WITH WEAK SSELY LLVL
UPSLOPE FLOW AND DIURNAL HEATING WILL LIKELY RESULT IN SCT SHOWERS
AND TSTMS BY AFTN ACROSS THE LAUREL HIGHLANDS/S-CENTRAL MTNS. 00Z
MDL QPFS ARE GENERALLY FAVORING THIS AREA INDICATING A RELATIVE
MAXIMUM FROM THE CUMBERLAND PLATEAU/WV-MD PNHDLS NWD INTO
S-CENTRAL PA.
THE 29/00Z ECMWF IS SHOWING A MOD-HVY QPF AXIS SHIFTING NEWD ACRS
THE AREA TOMORROW NIGHT. THE NCEP GUID ALONG WITH THE 12Z CANADIAN
GENERALLY DO NOT SHOW THIS FEATURE. THERE SHOULD BE A RATHER
ELONGATED/DIFFUSE FNTL BNDRY AROUND WHICH MAY ACT AS A FOCUS FOR
ORGANIZED PCPN...HOWEVER GIVEN THE UNCERTAINTY USED A MEAN BLEND
OF THE OPERATIONAL MODEL AND MOS DATA WHICH RESULTED IN MEDIUM TO
HIGH CHC POPS. ALSO WENT WARMER THAN GUID GIVEN PROSPECTS OF
CLOUDS AND THREAT OF PCPN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
ALL MED RANGE MDL DATA CONTINUES TO INDICATE THE SAME GENERAL
PATTERN OF A DIGGING UPPER LVL TROUGH OVR THE E GRT LKS AND OHIO
VALLEY TUE-WED. THIS SCENARIO WILL PLACE CENTRAL PA IN A
FAVORABLE POSITION FOR DIURNALLY-ENHANCED CONVECTION IN THE MOIST
SOUTHERLY FLOW AHEAD OF TROF. MOST SIGNIFICANT RAINFALL APPEARS
LIKELY ON TUESDAY WITH PASSAGE OF SHORTWAVE ACCOMPANIED BY
ANOMALOUS PWATS IN THE GEFS DATA. HOWEVER...ADDITIONAL SCT
SHRA/TSRA STILL APPEAR LIKELY WED...WHEN ALL MDL INDICATE ANOTHER
SHORTWAVE ROTATES THRU BASE OF EASTERN CONUS TROUGH.
BEST CHANCE FOR A COMPLETELY DRY DAY NEXT WEEK APPEARS TO BE
THURSDAY...AS HIGH PRES RIDGE AND SOMEWHAT DRIER AIR MASS BUILDS
OVR THE AREA. GEFS AND ECMWF ENSEMBLE 8H TEMPS INDICATE TEMPS WILL
BE NEAR SEASONAL NORMS NEXT WEEK. A RETURN TO WARMER...MORE HUMID
CONDS APPEAR LIKELY BY FRI/SAT...AS EASTERN TROUGH LIFTS OUT.
ANOTHER LOW SHOULD MOVE THROUGH PA LATE SUNDAY...EARLY MONDAY.
THIS CURRENTLY LOOKS TO HAVE STRONG UPPER LEVEL SUPPORT.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
29/18Z...SCT-BKN VFR CUMULUS WILL COVER MUCH OF THE CENTRAL AND
ERN AIRSPACE THIS AFTN. AN ISOLD SHRA/TSRA IS POSSIBLE ACRS THE
FAR ERN SXNS NEAR AXIS OF HIGH DEEP LYR MSTR ON BACKSIDE OF
EXITING MID-UPPER TROUGH. EXPECT CVRG TO REMAIN LIMITED AND
THEREFORE WILL NOT MENTION EXPLICITLY IN ERN TERMINALS. KLNS HAS
THE HIGHEST PROBABILITY. THE CU FIELD SHOULD DISSIPATE INTO TNT WITH
THE LOSS OF DAYTIME HEATING...GIVING WAY TO VFR AND M/CLEAR-CALM CONDS
FOR THE OVRNGT PD. SOME AREAS OF FOG ARE POSSIBLE DURING THE PRE-
DAWN HOURS MONDAY BUT SHOULD DISSIPATE BY 13-14Z.
OUTLOOK...
MON...MAINLY VFR. ISOLD-SCT PM TSTM IMPACTS POSSIBLE.
TUE-WED...VFR-MVFR WITH OCNL SHRA AND SCTD TSRA.
THU...FOG POSSIBLE EARLY...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...FITZGERALD/CERU
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
200 PM EDT SUN JUL 29 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL SHIFT EAST-NORTHEAST INTO NEW ENGLAND
TODAY...ALLOWING HIGH PRESSURE OVER THE LOWER GREAT LAKES TO
MOVE INTO CENTRAL PENNSYLVANIA THROUGH TONIGHT. ANOTHER UPPER
LEVEL TROUGH WILL MOVE EAST FROM THE OHIO VALLEY ON MONDAY AND
BECOME NEARLY STATIONARY OVER THE MID-ATLANTIC REGION. THIS
FEATURE WILL MAINTAIN AN UNSETTLED WEATHER PATTERN WITH SEVERAL
OPPORTUNITIES FOR RAIN THROUGH MUCH OF THE UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
18Z UPDATE...VIS SATL SHOWS CU FIELD HAS GENERALLY DECREASED IN
CVRG WITH MORE SUN THAN CLOUDS AT MOST LOCATIONS. RDR SHOWS
DEVELOPING SHOWERS OVR NRN SCHUYLKILL COUNTY EWD TO ABE VCNTY. THE
LATEST NEAR TERM MODEL GUID CONTINUES TO SHOW A MARGINAL/SLIGHT
INCREASE IN DIURNAL SHOWERS INTO THE MID AFTN WITH AN ISOLD TSTM
PSBL ACRS THE FAR ERN ZONES. RUC DATA ALONG WITH 16Z SATL DERIVED
TPW SHOW A LINGERING MSTR AXIS WITH PWATS BTWN 1-1.5 INCHES OVR
ERN PA. THEREFORE WILL MAINTAIN CHC POPS THRU THE LATE AFTN...WITH
ACTIVITY EXPECTED TO DISSIPATE WITH THE LOSS OF DAYTIME HEATING.
THE SHOWERS/ISOLD TSTMS MAY CONTAIN BRIEF HEAVY DOWNPOURS WITH A
GENERAL 360/15 STM MOTION.
THERE IS ALSO A LINE OF ENHANCED CU DOWNWIND OF LAKE ERIE ASSOC
WITH LAKE BREEZE FNT. INLAND DEWPTS QUICKLY DROP OFF INTO THE 50S
THEREFORE DO NOT EXPECT ISOLD SHOWERS TO REACH THE NW MTNS.
THE MID-UPPER TROUGH AND ASSOCD S/W ENERGY ALONG THE NRN MID-ATLC
- SRN NEW ENG COAST WILL CONTINUE TO LIFT NEWD INTO DOWNEAST MAINE
TONIGHT..ALLOWING SFC HIGH PRES TO OVERSPREAD CENTRAL PA FROM THE
LOWER GREAT LAKES. CLEAR/CALM CONDS AND NEAR TO SLIGHTLY BLW
NORMAL PWS WILL SUPPORT RELATIVELY COOL MINS RANGING FROM THE
LOW-MID 50S NORTH TO LOW-MID 60S SOUTH. SOME OF THE TYPICALLY
COLDER SPOTS IN THE NORTH MAY DIP INTO THE UPPER 40S. THE COOL
AIR...COMBINED WITH LIGHT WINDS AND RELATIVELY WARMER RIVER/STREAM
WATER WILL LIKELY RESULT IN PATCHY LATE NIGHT FOG IN THE DEEP
VALLEYS ACRS THE N-CENTRAL MTNS.
&&
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
HIGH PRES WILL SHIFT OFF THE NORTHEAST COAST ON MONDAY...ALLOWING
RETURN SOUTHERLY FLOW TO ADVECT HIGHER DEWPTS BACK INTO THE
REGION. LG SCALE FORCING AHEAD OF LOW AMPLITUDE H5 SHORTWAVE TROF
SWEEPING EWD THRU THE OHIO VALLEY...COMBINED WITH WEAK SSELY LLVL
UPSLOPE FLOW AND DIURNAL HEATING WILL LIKELY RESULT IN SCT SHOWERS
AND TSTMS BY AFTN ACROSS THE LAUREL HIGHLANDS/S-CENTRAL MTNS. 00Z
MDL QPFS ARE GENERALLY FAVORING THIS AREA INDICATING A RELATIVE
MAXIMUM FROM THE CUMBERLAND PLATEAU/WV-MD PNHDLS NWD INTO
S-CENTRAL PA.
THE 29/00Z ECMWF IS SHOWING A MOD-HVY QPF AXIS SHIFTING NEWD ACRS
THE AREA TOMORROW NIGHT. THE NCEP GUID ALONG WITH THE 12Z CANADIAN
GENERALLY DO NOT SHOW THIS FEATURE. THERE SHOULD BE A RATHER
ELONGATED/DIFFUSE FNTL BNDRY AROUND WHICH MAY ACT AS A FOCUS FOR
ORGANIZED PCPN...HOWEVER GIVEN THE UNCERTAINTY USED A MEAN BLEND
OF THE OPERATIONAL MODEL AND MOS DATA WHICH RESULTED IN MEDIUM TO
HIGH CHC POPS. ALSO WENT WARMER THAN GUID GIVEN PROSPECTS OF
CLOUDS AND THREAT OF PCPN.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
ALL MED RANGE MDL DATA CONTINUES TO INDICATE THE SAME GENERAL
PATTERN OF A DIGGING UPPER LVL TROUGH OVR THE E GRT LKS AND OHIO
VALLEY TUE-WED. THIS SCENARIO WILL PLACE CENTRAL PA IN A
FAVORABLE POSITION FOR DIURNALLY-ENHANCED CONVECTION IN THE MOIST
SOUTHERLY FLOW AHEAD OF TROF. MOST SIGNIFICANT RAINFALL APPEARS
LIKELY ON TUESDAY WITH PASSAGE OF SHORTWAVE ACCOMPANIED BY
ANOMALOUS PWATS IN THE GEFS DATA. HOWEVER...ADDITIONAL SCT
SHRA/TSRA STILL APPEAR LIKELY WED...WHEN ALL MDL INDICATE ANOTHER
SHORTWAVE ROTATES THRU BASE OF EASTERN CONUS TROUGH.
BEST CHANCE FOR A COMPLETELY DRY DAY NEXT WEEK APPEARS TO BE
THURSDAY...AS HIGH PRES RIDGE AND SOMEWHAT DRIER AIR MASS BUILDS
OVR THE AREA. GEFS AND ECMWF ENSEMBLE 8H TEMPS INDICATE TEMPS WILL
BE NEAR SEASONAL NORMS NEXT WEEK. A RETURN TO WARMER...MORE HUMID
CONDS APPEAR LIKELY BY FRI/SAT...AS EASTERN TROUGH LIFTS OUT.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
29/18Z...SCT-BKN VFR CUMULUS WILL COVER MUCH OF THE CENTRAL AND
ERN AIRSPACE THIS AFTN. AN ISOLD SHRA/TSRA IS POSSIBLE ACRS THE
FAR ERN SXNS NEAR AXIS OF HIGH DEEP LYR MSTR ON BACKSIDE OF
EXITING MID-UPPER TROUGH. EXPECT CVRG TO REMAIN LIMITED AND
THEREFORE WILL NOT MENTION EXPLICITLY IN ERN TERMINALS. KLNS HAS
THE HIGHEST PROBABILITY. THE CU FIELD SHOULD DISSIPATE INTO TNT WITH
THE LOSS OF DAYTIME HEATING...GIVING WAY TO VFR AND M/CLEAR-CALM CONDS
FOR THE OVRNGT PD. SOME AREAS OF FOG ARE POSSIBLE DURING THE PRE-
DAWN HOURS MONDAY BUT SHOULD DISSIPATE BY 13-14Z.
OUTLOOK...
MON...MAINLY VFR. ISOLD-SCT PM TSTM IMPACTS POSSIBLE.
TUE-WED...VFR-MVFR WITH OCNL SHRA AND SCTD TSRA.
THU...FOG POSSIBLE EARLY...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...FITZGERALD
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
951 PM CDT MON JUL 30 2012
.DISCUSSION.../ISSUED AT 951 PM CDT/
FORECAST IN PRETTY GOOD SHAPE THIS EVENING...ALTHOUGH SEEING TEMPS
DROP OFF MORE QUICKLY THAN EXPECTED IN A FEW PLACES. HAVE TWEAKED
HOURLY GRIDS ACCORDINGLY...WITH MINOR UPDATES TO LOW TEMPERATURES.
WITH THE COOLING...LIGHT WINDS...AND RECENT RAINS ACROSS THE EAST...
HAVE ADDED SOME PATCHY FOG INTO SOME OF OUR MN/IA COUNTIES AGAIN FOR
LATE TONIGHT..AND UPDATED GRIDS/ZFP/PFM HAVE BEEN SENT FOR THAT.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
ISOLATED MID LEVEL SPRINKLES MAY DEVELOP ALONG A WEAK COLD FRONT
ACROSS NORTHWEST IOWA THROUGH 02Z. OTHERWISE...EXPECT VFR
CONDITIONS TO PERSIST ACROSS THE AREA THROUGH 00Z TUESDAY.
&&
.PREV DISCUSSION.../ISSUED AT 315 PM CDT/
SURFACE FRONT MOVING THROUGH NORTHWEST IOWA AS OF 19Z WITH MAIN PUSH
OF COOLER AIR APPROACHING I90. THE COOLER AIR SHOULD SPREAD SOUTH
ACROSS THE CWA OVERNIGHT WITH LOWS EXPECTED TO BE IN THE LOWER TO
MID 60S. WILL KEEP A VERY SMALL CHANCE OF STORMS ACROSS FAR
SOUTHEAST CWA THROUGH EARLY EVENING AS LATEST SATELLITE SHOWING SOME
ACCAS TRYING TO FORM FROM SOUTH OF SPW TO NEAR SUX AND WITH
TEMPERATURES GETTING CLOSE TO BREAKING CAP THERE CAN NOT RULE A FEW
STORMS YET LATE THIS AFTERNOON AND EARLY EVENING AS WEAK WAVE DROPS
SOUTHEAST INTO SOUTHWEST MINNESOTA WHICH ALSO SHOWS UP WELL ON
SATELLITE. LATEST HRRR MODELS CONTINUES TO CONFIRM THIS POSSIBILITY.
OTHERWISE...EXPECT MOSTLY CLEAR SKIES OVERNIGHT.
SOMEWHAT ACTIVE WEATHER PATTERN EXPECTED INTO THE END OF THE WEEK AS
THE PATTERN TRANSITIONS FROM A SHARP HIGH PLAINS RIDGE INTO A MORE
ZONAL PATTERN BY LATE WEEK. IN THE SHORT RANGE...EXPECT A FEW FAIRLY
WEAK WAVES TO DROP SOUTHEAST FROM SOUTHERN CANADA INTO THE NORTHERN
PLAINS. AS IS TYPICAL FOR THESE WEAK WAVE SCENARIOS...MODELS NOT
SHOWING MUCH CONSISTENCY IN THE TIMING AND TRACK OF THESE WAVES
DURING THE MID WEEK. GIVEN THE MEAGER MOISTURE...CONDITIONAL
INSTABILITY AND MODEL UNCERTAINTY...IT IS HARD TO PINPOINT ANY ONE
TIME FRAME AS THE "BETTER" POTENTIAL FOR SHOWER OR THUNDERSTORM
ACTIVITY. WITH THIS IN MIND...WILL KEEP ISOLATED POPS IN THE
FORECAST JUST ABOUT EVERY PERIOD FROM TUESDAY NIGHT THROUGH
THURSDAY. ANY ACTIVITY THAT MANAGES TO DEVELOP SHOULD BE HIGH BASED
AND NOT A HEAVY RAIN PRODUCER. HIGHS WILL BE QUITE WARM ON WEDNESDAY
WITH THE 90S TO NEAR 100 EXPECTED...AND WILL BE AROUND 5 DEGREES
COOLER ON THURSDAY.
LATE IN THE WEEK MARKS THE APPROACH OF A CUT OFF UPPER LOW WHICH
DIGS ALONG THE CANADIAN BORDER WITH MONTANA ON FRIDAY THEN HEADS
INTO THE NORTHERN GREAT LAKES BY SATURDAY NIGHT. THERE ARE SOME
FAIRLY SIGNIFICANT MODEL DIFFERENCES WITH THIS SYSTEM. THE LATEST
ECMWF...ONCE THE FASTEST SOLUTION...IS NOW 6 TO 12 HOURS SLOWER AND
IS THE WEAKEST SOLUTION. THE GEM TAKES THE LOW FARTHER SOUTH INTO
THE NORTHERN PLAINS WHILE THE GFS IS SLIGHTLY STRONGER AND THE MOST
NORTHERN TRACK. ALL OF THESE SOLUTIONS DO SEND A FAIRLY STRONG FRONT
THROUGH THE FORECAST AREA FRIDAY NIGHT OR SATURDAY WHICH APPEARS TO
BE THE BEST POTENTIAL FOR SOME WET WEATHER IN THE NEXT SEVEN DAYS.
WILL CONTINUE CARRYING LIKELY POPS FRIDAY NIGHT IN OUR NORTHERN HALF
WITH CHANCES ELSEWHERE. WITH THE INCREASED CLOUD COVERAGE AND
RAINFALL CHANCES FRIDAY AND SATURDAY...AS WELL AS COOLER NORTHWEST
FLOW WORKING INTO THE AREA SATURDAY AND SUNDAY...TEMPERATURES WILL
BE MUCH CLOSER TO NORMALS INTO THE WEEKEND.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
529 PM CDT SUN JUL 29 2012
.UPDATE...
SENDING OUT A QUICK UPDATE TO EXTEND SLIGHT CHANCE POPS FURTHER
EASTWARD BASED ON LATEST RADAR TRENDS. AREA OF LIGHT RAIN MOVING
SOUTHEASTWARD CONTINUES TO WEAKEN AND SHRINK IN SIZE...BUT PRECIP
IS NEVERTHELESS MAKING IT FURTHER EASTWARD THAN CURRENT
GRIDS/ZONES INDICATE. REST OF FORECAST IS UNCHANGED.
&&
.PREV DISCUSSION... /ISSUED 305 PM CDT SUN JUL 29 2012/
DISCUSSION...TEMPS WERE A LITTLE LOWER THIS AFTN COMPARED TO
SATURDAY IN THE WAKE OF YESTERDAY/S WEAK FRONT PLUS THE CLOUD
COVER THAT HAS BEEN INCREASING FROM THE NORTHWEST TODAY. AN AREA
OF SHOWERS HAS BEEN APPROACHING MID TN FROM THE NORTHWEST ALL DAY
AND HAS REFUSED TO WEAKEN. SOME LIGHT RETURNS ON 88D WERE NOTED IN
NW COUNTIES AT 19Z. HRRR SEEMS TO BE HANDLING THIS PRECIP BETTER
THE PAST COUPLE HOURS...AND IT SHOWS THE AREA GRADUALLY WEAKENING
AS IT MOVES THROUGH WEST MIDDLE TN DURING NEXT SEVERAL HOURS BEFORE
DISSIPATING BEFORE 00Z.
FOR THE WEEK AHEAD...MODELS AGREE THAT NORTHWEST FLOW WILL
CONTINUE ALOFT THROUGH MOST OF THE WEEK AS H5 RIDGE...CENTERED
OVER WESTERN OKLAHOMA AT 12Z TODAY...STAYS IN THE VCNTY OF THE TX
PANHANDLE THROUGH AT LEAST THURSDAY. THIS PATTERN LEAVES TN
VULNERABLE TO WEAK SHORT WAVES APPROACHING FROM THE NW...
ESPECIALLY OVER THE NEXT COUPLE DAYS.
THE NEXT S/W TO APPROACH US WAS OVER SOUTHERN MN AT 12Z. MODELS
ARE INCONSISTENT IN HANDLING PRECIP FROM THIS S/W AS WELL AS THE
NEXT ONE. THE NAM HITS THE FIRST ONE HARDER LATE TONIGHT AND
MONDAY...WHILE THE GFS HITS THE SECOND ONE HARDER ON MONDAY NIGHT
AND TUESDAY. CANNOT HAVE CONFIDENCE IN MODEL TIMING EITHER OF
THESE WAVES BUT 20 TO 30 POPS ARE CERTAINLY WARRANTED AREA WIDE FOR
MOST OF THE WEEK. CONVECTION MAY BE MINIMIZED ON WEDNESDAY AS
MODELS SHOW LOWER MEAN HUMIDITY BEHIND THE SECOND S/W.
BY FRIDAY AND NEXT WEEKEND...THE H5 RIDGE ELONGATES ACROSS THE
WHOLE SOUTHERN U.S. AND ENDS OUR NW FLOW PATTERN. THUS...NORMAL
SUMMER DIURNAL CONVECTION EXPECTED WITH 20 TO 30 PERCENT CHANCE OF
AFTN/EVENING STORMS. TEMPS WILL CONTINUE ABOVE SEASONAL NORMS
WITH HIGHS IN 90S AND LOWS IN 70S EXCEPT A FEW DEGREES LOWER ON
THE PLATEAU.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
305 PM CDT SUN JUL 29 2012
.DISCUSSION...TEMPS WERE A LITTLE LOWER THIS AFTN COMPARED TO
SATURDAY IN THE WAKE OF YESTERDAY/S WEAK FRONT PLUS THE CLOUD
COVER THAT HAS BEEN INCREASING FROM THE NORTHWEST TODAY. AN AREA
OF SHOWERS HAS BEEN APPROACHING MID TN FROM THE NORTHWEST ALL DAY
AND HAS REFUSED TO WEAKEN. SOME LIGHT RETURNS ON 88D WERE NOTED IN
NW COUNTIES AT 19Z. HRRR SEEMS TO BE HANDLING THIS PRECIP BETTER
THE PAST COUPLE HOURS...AND IT SHOWS THE AREA GRADUALLY WEAKENING
AS IT MOVES THROUGH WEST MIDDLE TN DURING NEXT SEVERAL HOURS BEFORE
DISSIPATING BEFORE 00Z.
FOR THE WEEK AHEAD...MODELS AGREE THAT NORTHWEST FLOW WILL
CONTINUE ALOFT THROUGH MOST OF THE WEEK AS H5 RIDGE...CENTERED
OVER WESTERN OKLAHOMA AT 12Z TODAY...STAYS IN THE VCNTY OF THE TX
PANHANDLE THROUGH AT LEAST THURSDAY. THIS PATTERN LEAVES TN
VULNERABLE TO WEAK SHORT WAVES APPROACHING FROM THE NW...
ESPECIALLY OVER THE NEXT COUPLE DAYS.
THE NEXT S/W TO APPROACH US WAS OVER SOUTHERN MN AT 12Z. MODELS
ARE INCONSISTENT IN HANDLING PRECIP FROM THIS S/W AS WELL AS THE
NEXT ONE. THE NAM HITS THE FIRST ONE HARDER LATE TONIGHT AND
MONDAY...WHILE THE GFS HITS THE SECOND ONE HARDER ON MONDAY NIGHT
AND TUESDAY. CANNOT HAVE CONFIDENCE IN MODEL TIMING EITHER OF
THESE WAVES BUT 20 TO 30 POPS ARE CERTAINLY WARRANTED AREA WIDE FOR
MOST OF THE WEEK. CONVECTION MAY BE MINIMIZED ON WEDNESDAY AS
MODELS SHOW LOWER MEAN HUMIDITY BEHIND THE SECOND S/W.
BY FRIDAY AND NEXT WEEKEND...THE H5 RIDGE ELONGATES ACROSS THE
WHOLE SOUTHERN U.S. AND ENDS OUR NW FLOW PATTERN. THUS...NORMAL
SUMMER DIURNAL CONVECTION EXPECTED WITH 20 TO 30 PERCENT CHANCE OF
AFTN/EVENING STORMS. TEMPS WILL CONTINUE ABOVE SEASONAL NORMS
WITH HIGHS IN 90S AND LOWS IN 70S EXCEPT A FEW DEGREES LOWER ON
THE PLATEAU.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 68 95 74 95 / 20 20 30 30
CLARKSVILLE 66 93 72 94 / 30 20 30 30
CROSSVILLE 61 87 68 86 / 10 20 30 50
COLUMBIA 68 96 74 96 / 20 20 30 40
LAWRENCEBURG 67 95 73 96 / 20 20 30 30
WAVERLY 68 94 73 95 / 30 20 30 30
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
49
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
632 PM CDT MON JUL 30 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY
247 PM CDT MON JUL 30 2012
MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES THIS
EVENING. FOCUS THEN TURNS TO VALLEY FOG POTENTIAL TONIGHT AND AGAIN
WEDNESDAY NIGHT AND SHOWER/THUNDERSTORM CHANCES WEDNESDAY NIGHT
INTO THURSDAY.
LATEST SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
IRONWOOD MICHIGAN...TO NEAR RICE LAKE WISCONSIN...TO NEAR ST.
JAMES MINNESOTA...DRIFTING SOUTHEAST. MESOSCALE FORECAST MODELS
CONTINUE TO SUGGEST THAT SHOWERS AND THUNDERSTORMS WILL FIRE ALONG
THIS FRONT IN THE 4 TO 6 PM TIME FRAME. THIS WOULD PUT THE FRONT
OVER CENTRAL WISCONSIN...EXTENDING SOUTHWEST INTO NORTHEAST IOWA.
LATEST VISIBLE SATELLITE IMAGERY SHOWED A WELL DEFINED CUMULUS
FIELD AHEAD OF THE FRONT. NO PRECIPITATION RETURNS ON RADAR YET
ALONG THIS FIELD. THINKING THE FRONT WILL FINALLY GENERATE
CONVECTION AS IT MOVES INTO CENTRAL AND FAR SOUTHWEST
WISCONSIN...EXTENDING INTO NORTHEAST IOWA. DRY LOW LEVELS WILL LEAD
TO THE POTENTIAL FOR DAMAGING WINDS WITH ANY STORMS THAT DEVELOP.
LATEST RAP ANALYSIS INDICATES NEARLY 1400-1600 DOWNDRAFT CAPE
AHEAD OF THE COLD FRONT. 0-6 KM SHEAR IS RATHER WEAK...GENERALLY
LESS THAN 30 KTS...SO STORMS MAY STRUGGLE TO BECOME ORGANIZED ONCE
THEY DEVELOP. SURFACE BASED CAPE VALUES OF NEARLY 4000 J/KG WILL
LEAD TO STRONG UPDRAFTS...WITH MARGINALLY SEVERE HAIL POSSIBLE.
THE COLD FRONT WILL PUSH EAST OF THE FORECAST AREA LATE THIS EVENING
WITH HIGH PRESSURE BUILDING INTO THE REGION. FORECAST SOUNDINGS ARE
SHOWING THE POTENTIAL FOR SOME VALLEY FOG DEVELOPMENT ALONG THE
MISSISSIPPI RIVER. THE AIR MASS LOOKS A BIT ON THE DRY SIDE FOR THIS
TO OCCUR. TEMPERATURE AND DEW POINT SPREADS AT KLSE APPROACH TWO
DEGREES BUT THIS OCCURS LATE IN THE NIGHT/EARLY MORNING...AROUND
11Z. WINDS ARE MORE FAVORABLE...WITH LIGHT WIND FROM THE SURFACE
THROUGH 2 KFT. THINKING A BRIEF PERIOD OF PATCHY VALLEY FOG IS
POSSIBLE TONIGHT...ESPECIALLY IF ANY PRECIPITATION FALLS THIS
EVENING. ANOTHER FACTOR POSSIBLY WORKING AGAINST VALLEY FOG IS A LOW
CLOUD DECK APPROACHING THE FORECAST AREA BEHIND THE COLD FRONT.
THESE CLOUDS LOOK TO PASS JUST EAST OF THE MISSISSIPPI SO WILL HAVE
TO KEEP A CLOSE WATCH ON THESE. OTHERWISE...PLAN ON SKIES RANGING
FROM MOSTLY CLEAR TO PARTLY CLOUD DURING THE OVERNIGHT HORUS. LOOK
FOR LOW TEMPERATURES WILL RANG FROM LOWER 60S ACROSS NORTHERN
WISCONSIN TO THE UPPER 60 OVER NORTHEAST IOWA.
SLIGHTLY COOLER AIR WILL MOVE INTO THE REGION BEHIND THE FRONT LATE
TONIGHT INTO TUESDAY. 850 MB TEMPERATURES WILL FALL FROM 22C MONDAY
AFTERNOON INTO THE 14 TO 16 C RANGE BY EARLY TUESDAY MORNING. HIGH
PRESSURE WILL BE IN CONTROL THROUGH THE DAY ON TUESDAY PROVIDING
MOSTLY SUNNY SKIES. PLAN ON HIGHS RANGING FROM THE LOWER 80S ACROSS
NORTHERN WISCONSIN TO THE UPPER 80S OVER NORTHEAST IOWA.
HIGH PRESSURE IS EXPECTED TO SLIDE EAST OF THE FORECAST AREA TUESDAY
NIGHT INTO WEDNESDAY MORNING AS ANOTHER COLD FRONT APPROACHES FROM
WESTERN MINNESOTA AND EAST SOUTH DAKOTA. FORECAST SOUNDINGS AGAIN
SHOW THE POTENTIAL FOR SOME VALLEY FOG. HIGH PRESSURE WILL BE
SETTLED OVER THE AREA DURING THE OVERNIGHT HOURS PROVIDING LIGHT AND
VARIABLE WINDS. TEMPERATURE/DEW POINT SPREADS APPROACH TWO DEGREES
BY 09Z. WILL HAVE TO KEEP A CLOSE WATCH ON SOME HIGH CLOUDS TRYING
TO STREAM IN FROM THE WEST. CURRENT THINKING IS THAT AREAS OF FOG
WILL DEVELOP ALONG THE MISSISSIPPI AND WISCONSIN RIVER VALLEY.
FORECAST MODELS ARE SHOWING VERY DRY AIR ADVECTING INTO THE AREA
AHEAD OF THE APPROACHING FRONT. WINDS WILL SHIFT TO THE SOUTHWEST
BY WEDNESDAY AFTERNOON AS THE FRONT APPROACHES. DEW POINTS PLUMMET
AS THIS OCCURS...ESPECIALLY ACROSS NORTHEAST IOWA...PORTIONS OF
SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN. COULD SEE DEW POINTS
FALL INTO THE MID 40S BY THE MID AFTERNOON HOURS. THE COLD FRONT
IS EXPECTED TO MOVE INTO THE AREA LATE WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT AS A SHORTWAVE TROUGH MOVES OVER THE UPPER
MISSISSIPPI RIVER VALLEY. THE FRONT AND SHORTWAVE WILL NOT HAVE
MUCH MOISTURE TO WORK WITH AS THE DRY AIR ADVECTS IN FROM THE
SOUTHWEST...WITH A FAIRLY DEEP ELEVATED MIXED LAYER IN PLACE.
EXPECT TO SEE SOME SHOWERS AND ISOLATED THUNDERSTORMS AS THIS
FEATURE MOVES THROUGH. RATHER HIGH BASED ACTIVITY WITH CLOUD BASES
IN THE 8 TO 10KFT RANGE. GUSTY WINDS WOULD BE A CONCERN WITH ANY
SHOWER/STORM ACTIVITY THAT DEVELOPS. ANOTHER SHORTWAVE IS
EXPECTED TO MOVE OVER THE REGION DURING THE DAY ON THURSDAY.
AGAIN THE ELEVATED MIXED LAYER AND CAPPING WILL BE A FACTOR. 0-3KM
MUCAPE WILL CLIMB TO AROUND 2000 J/KG THURSDAY AFTERNOON BUT
QUICKLY WANES DURING THE AFTERNOON AS WEAK SURFACE HIGH PRESSURE
ATTEMPTS TO BUILD IN FROM THE EAST. WILL MAINTAIN A CHANCE OF
SHOWERS AND THUNDERSTORMS ON THURSDAY GIVEN THE SHORTWAVE MOVING
THROUGH.
.LONG TERM...FRIDAY THROUGH MONDAY
247 PM CDT MON JUL 30 2012
30.12 MEDIUM RANGE MODELS IN AGREEMENT FRIDAY INTO
SATURDAY...SHOWING A POTENT UPPER LEVEL TROUGH MOVING ACROSS THE
DAKOTAS AND PUSHING INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE
TROUGH IS EXPECTED TO CLOSE INTO AN UPPER LOW OVER EASTERN NORTH
DAKOTA/NORTHERN MINNESOTA DURING THE DAY ON SATURDAY...PUSHING A
COLD FRONT ACROSS THE AREA. GIVEN THE STRONG DYNAMICS OF THIS SYSTEM
AND STRONG MOISTURE RETURN AHEAD OF IT...FOCUSED INTO THE FORECAST
AREA...A SEVERE WEATHER EVENT LOOKS POSSIBLE. TIMING OF THE FRONT
AND ANY MCS ACTIVITY AHEAD OF IT WILL HAVE AN IMPACT ON CONVECTION
OVER THE FORECAST AREA. EXACT DETAILS ARE UNCLEAR AT THIS TIME BUT
WILL HAVE TO KEEP A VERY CLOSE WATCH ON THE NEXT FEW FORECAST MODEL
RUNS. CURRENT THINKING IS THAT THE AREA COULD SEE AN MCS MOVE
THROUGH SATURDAY MORNING...WITH STORMS REDEVELOPING ALONG THE COLD
FRONT SATURDAY AFTERNOON. PLAN ON HIGHS ON FRIDAY RANGING FORM THE
LOWER 80S OVER NORTHERN WISCONSIN TO THE MID 80S ACROSS NORTHEAST
IOWA. LOOK FOR OVERNIGHT LOWS IN THE 60S. SLIGHTLY COOLER AIR WILL
MOVE IN BEHIND THE FRONT ON SUNDAY WITH HIGHS FALLING INTO THE 70S
TO LOWER 80S.
&&
.AVIATION...TONIGHT AND TUESDAY
632 PM CDT MON JUL 30 2012
MAIN COLD FRONT HAS PUSHED SOUTH OF THE TAF SITES LATE THIS
AFTERNOON. OUTSIDE OF A FEW CUMULUS EARLY...ONLY SOME HIGH CLOUDS
ARE EXPECTED OVERNIGHT WITH CONVECTION REMAINING SOUTH OF THE
AREA. HIGH PRESSURE SETTLES IN...BUT RAP AND NAM SOUNDINGS SHOWING
WINDS REMAINING AT OR ABOVE 10 KNOTS ALOFT AND THUS NOT EXPECTING
ANY FOG POTENTIAL. IF WINDS SHOULD DECOUPLE...COULD SEE SOME BCFG
IN THE MISSISSIPPI RIVER VALLEY TOWARDS MORNING. OTHERWISE...HIGH
PRESSURE WILL KEEP VFR CONDITIONS THROUGH 00Z WEDNESDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
247 PM CDT MON JUL 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
643 AM CDT SUN JUL 29 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
306 AM CDT SUN JUL 29 2012
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE RAIN CHANCES
TODAY AND MONDAY.
A FEW DIFFERENT BANDS OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
ACROSS THE REGION AHEAD OF A 850-500MB TROUGH MOVING THROUGH
MINNESOTA. THIS LOW TO MID LEVEL FORCING WILL PROVIDE THE LIFT TO
KEEP CONVECTION GOING THROUGH THE MORNING HOURS TODAY BEFORE THE
TROUGH MAKES IT INTO EASTERN WISCONSIN THIS AFTERNOON. INSTABILITY
REMAINS RATHER WEAK NEAR THE NORTHERN BAND OF SHOWERS AT LESS
THAN 500 J/KG OF 0-3KM MUCAPE WHILE AN AXIS OF 500-1000 J/KG OF
MUCAPE IS NOSING UP INTO THE CONVECTION IN SOUTHWEST MINNESOTA AND
HAS LED TO SOME MORE LIGHTNING STRIKES THERE. THE BEST CHANCES
FOR ANY PRECIPITATION APPEAR TO BE ALONG AND WEST OF THE
MISSISSIPPI RIVER WITH THE CONVECTION DEVELOPING IN SOUTHWEST
MINNESOTA AHEAD OF THE TROUGH. THIS CONVECTION SHOULD BECOME MORE
WIDESPREAD THROUGH THE MORNING AND TRACK THROUGH SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. MEANWHILE...THE DEFORMATION BAND
ALONG A 800-600MB ZONE HAS SET UP FROM WEST CENTRAL MINNESOTA INTO
CENTRAL WISCONSIN. THE 29.02Z THROUGH 29.04Z HRRR HAS DONE A
FAIRLY GOOD JOB OF PICKING UP ON CURRENT TRENDS AND SHOWS THIS
BAND STICKING TOGETHER THOUGH DIMINISHING IN COVERAGE THROUGH THE
MORNING. BASED ON THIS...HAVE PULLED SOME OF THE HIGHER CHANCES TO
THE NORTHEAST INTO CENTRAL WISCONSIN THOUGH ANY RAINFALL AMOUNTS
SHOULD BE ON THE LOW SIDE. THIS PRECIPITATION LOOKS TO BE ON A
DIMINISHING TREND INTO THE AFTERNOON WITH MUCH OF THE REGION
CLEARING OUT BY THE EVENING AS A SURFACE RIDGE OF HIGH PRESSURE
EXTENDS WEST FROM THE GREAT LAKES INTO THE REGION.
WITH THIS RIDGE SITTING OVER THE REGION IN THE EVENING AND
OVERNIGHT HOURS...WINDS WILL GO CALM WITH SKIES CLEARING OUT.
WITH A FRESH RAINFALL POSSIBLE ACROSS MUCH OF THE REGION THIS
MORNING...EXPECT THAT THERE MAY BE SOME FOG THAT DEVELOPS
TONIGHT/TOMORROW MORNING. 29.00Z NAM/GFS FORECAST SOUNDINGS
SUPPORT THIS IDEA AS WELL WITH LIGHT WINDS LESS THAN 10KTS UP TO
AROUND 5KFT AND SURFACE DEW POINT DEPRESSIONS DOWN TO AROUND 1C BY
3Z TONIGHT. CONFIDENCE WAS NOT HIGH ENOUGH AT THIS POINT TO PUT A
WIDESPREAD MENTION IN THE FORECAST THOUGH HAVE PUT SOME IN ACROSS
THE VALLEY REGIONS.
THE FOCUS THEN GOES TO THE NEXT TROUGH THAT DIGS TO THE SOUTHEAST
ACROSS SOUTH CENTRAL CANADA INTO THE NORTHERN GREAT LAKES ON
MONDAY. THIS FEATURE PULLS A COLD FRONT DOWN ALONG WITH IT WITH
THE QUESTION BEING HOW FAR SOUTHWEST ALONG THE FRONT WILL
CONVECTION DEVELOP. THE LOW LEVEL MOISTURE TRANSPORT SOURCE FOR
THIS SYSTEM IS THE NORTHERN PLAINS WITH THE GULF CUT OFF BY THE
RIDGE TO THE SOUTH...WHICH MEANS THAT THERE IS NOT MUCH MOISTURE
AVAILABLE TO WORK WITH. THE TIMING ISSUES BETWEEN THE MODELS
APPEAR TO BECOMING LESS WITH THE TREND GOING TOWARD THE FASTER
NAM. ACCORDING TO THE 29.00Z NAM...THE MAIN LIFT IS IN THE LOW
LEVELS AHEAD OF THE COLD FRONT AHEAD OF WHEN THE MID LEVEL TROUGH
MOVES IN...SO THERE SHOULD NOT BE MUCH UPPER LEVEL INFLUENCE HERE.
INSTABILITY IS DECENT IN THE 1000-2000 J/KG RANGE WITH THE NAM/GFS
LIKELY OVER-FORECASTING THE SBCAPE DUE THEIR SURFACE DEW POINTS
BEING IN THE UPPER 60S TO LOW 70S WHEN WE WILL MORE LIKELY BE IN
THE MID 60S. 29.00Z NAM FORECAST SOUNDINGS WOULD ALSO SUGGEST THAT
THE ATMOSPHERE IS CAPPED FROM AN INVERSION AROUND 750MB THAT WOULD
STRENGTHEN WITH LOWER SFC DEW POINTS. BASED ON THIS...HAVE FOCUSED
THE BETTER CHANCES TO CENTRAL WISCONSIN WHERE THE COMBINATION OF
FORCING AND LESS OF A CAP MAY LEAD TO SOME CONVECTION BUT HAVE
LEFT SOME SLIGHT CHANCES IN TO THE SOUTHWEST ALONG THE FRONT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
306 AM CDT SUN JUL 29 2012
NOT MUCH CONFIDENCE IN THE LATER PART OF THE WEEK WITH THE UPPER
LEVEL FLOW EXPECTED TO BECOME MORE ZONAL TOWARD NEXT WEEKEND.
SURFACE HIGH PRESSURE WILL BE IN PLACE WEDNESDAY BEFORE A COLD
FRONT DROPS DOWN INTO THE REGION WEDNESDAY NIGHT AND THURSDAY.
THIS FRONT THEN APPEARS TO STALL OUT ACROSS THE REGION WHICH KEEPS
PRECIPITATION CHANCES AROUND THROUGH THE REST OF THE WEEK. SOME
TIMING DIFFERENCES WITH THE FRONT VIA THE 29.00Z GFS/ECMWF LEADS
TO HAVING THE CHANCES THROUGH THE WEEK THOUGH THERE WILL LIKELY BE
SOME BREAKS AT TIMES. TEMPERATURE-WISE IT STILL LOOKS FAIRLY
SEASONAL WITH NOT MUCH IN THE WAY OF CHANGES DUE TO WEAK LOW LEVEL
WARM AIR ADVECTION.
&&
.AVIATION...TODAY AND TONIGHT
642 AM CDT SUN JUL 29 2012
A SHORT WAVE TROUGH WILL MOVE SOUTHEAST THROUGH THE AREA THIS
MORNING. THIS SYSTEM WILL BRING WITH IT SHOWERS AND ISOLATED
THUNDERSTORMS TO THE AREA. WITH THE BEST INSTABILITY SOUTH OF THE
TAF SITES... DID NOT INCLUDE ANY THUNDERSTORMS IN THE TAFS.
CEILINGS WILL BE MAINLY VFR. HOWEVER THERE ARE A FEW PATCHES OF
BROKEN IFR AT THE SHOWERS ONSET. THE VISIBILITIES WILL BE MAINLY
VFR. HOWEVER IT MAY BRIEFLY BECOME MVFR IN THE HEAVIER SHOWERS.
STRONG SUBSIDENCE WILL MOVE INTO THE AREA IN THE WAKE OF THIS
SYSTEM. THIS SHOULD RESULT IN CLEARING SKIES FOR THIS AFTERNOON.
THE LAMP GUIDANCE DEVELOPS DENSE FOG AT BOTH TAF SITES FOR MONDAY
MORNING. WITH DRY SOILS AND SOME CLEARING THIS AFTERNOON...NOT
CONVINCED THAT THIS WILL HAPPEN...SO DID NOT INCLUDE IT IN THE TAFS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CDT SUN JUL 29 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
306 AM CDT SUN JUL 29 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
306 AM CDT SUN JUL 29 2012
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE RAIN CHANCES
TODAY AND MONDAY.
A FEW DIFFERENT BANDS OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED
ACROSS THE REGION AHEAD OF A 850-500MB TROUGH MOVING THROUGH
MINNESOTA. THIS LOW TO MID LEVEL FORCING WILL PROVIDE THE LIFT TO
KEEP CONVECTION GOING THROUGH THE MORNING HOURS TODAY BEFORE THE
TROUGH MAKES IT INTO EASTERN WISCONSIN THIS AFTERNOON. INSTABILITY
REMAINS RATHER WEAK NEAR THE NORTHERN BAND OF SHOWERS AT LESS
THAN 500 J/KG OF 0-3KM MUCAPE WHILE AN AXIS OF 500-1000 J/KG OF
MUCAPE IS NOSING UP INTO THE CONVECTION IN SOUTHWEST MINNESOTA AND
HAS LED TO SOME MORE LIGHTNING STRIKES THERE. THE BEST CHANCES
FOR ANY PRECIPITATION APPEAR TO BE ALONG AND WEST OF THE
MISSISSIPPI RIVER WITH THE CONVECTION DEVELOPING IN SOUTHWEST
MINNESOTA AHEAD OF THE TROUGH. THIS CONVECTION SHOULD BECOME MORE
WIDESPREAD THROUGH THE MORNING AND TRACK THROUGH SOUTHEAST
MINNESOTA AND NORTHEAST IOWA. MEANWHILE...THE DEFORMATION BAND
ALONG A 800-600MB ZONE HAS SET UP FROM WEST CENTRAL MINNESOTA INTO
CENTRAL WISCONSIN. THE 29.02Z THROUGH 29.04Z HRRR HAS DONE A
FAIRLY GOOD JOB OF PICKING UP ON CURRENT TRENDS AND SHOWS THIS
BAND STICKING TOGETHER THOUGH DIMINISHING IN COVERAGE THROUGH THE
MORNING. BASED ON THIS...HAVE PULLED SOME OF THE HIGHER CHANCES TO
THE NORTHEAST INTO CENTRAL WISCONSIN THOUGH ANY RAINFALL AMOUNTS
SHOULD BE ON THE LOW SIDE. THIS PRECIPITATION LOOKS TO BE ON A
DIMINISHING TREND INTO THE AFTERNOON WITH MUCH OF THE REGION
CLEARING OUT BY THE EVENING AS A SURFACE RIDGE OF HIGH PRESSURE
EXTENDS WEST FROM THE GREAT LAKES INTO THE REGION.
WITH THIS RIDGE SITTING OVER THE REGION IN THE EVENING AND
OVERNIGHT HOURS...WINDS WILL GO CALM WITH SKIES CLEARING OUT.
WITH A FRESH RAINFALL POSSIBLE ACROSS MUCH OF THE REGION THIS
MORNING...EXPECT THAT THERE MAY BE SOME FOG THAT DEVELOPS
TONIGHT/TOMORROW MORNING. 29.00Z NAM/GFS FORECAST SOUNDINGS
SUPPORT THIS IDEA AS WELL WITH LIGHT WINDS LESS THAN 10KTS UP TO
AROUND 5KFT AND SURFACE DEW POINT DEPRESSIONS DOWN TO AROUND 1C BY
3Z TONIGHT. CONFIDENCE WAS NOT HIGH ENOUGH AT THIS POINT TO PUT A
WIDESPREAD MENTION IN THE FORECAST THOUGH HAVE PUT SOME IN ACROSS
THE VALLEY REGIONS.
THE FOCUS THEN GOES TO THE NEXT TROUGH THAT DIGS TO THE SOUTHEAST
ACROSS SOUTH CENTRAL CANADA INTO THE NORTHERN GREAT LAKES ON
MONDAY. THIS FEATURE PULLS A COLD FRONT DOWN ALONG WITH IT WITH
THE QUESTION BEING HOW FAR SOUTHWEST ALONG THE FRONT WILL
CONVECTION DEVELOP. THE LOW LEVEL MOISTURE TRANSPORT SOURCE FOR
THIS SYSTEM IS THE NORTHERN PLAINS WITH THE GULF CUT OFF BY THE
RIDGE TO THE SOUTH...WHICH MEANS THAT THERE IS NOT MUCH MOISTURE
AVAILABLE TO WORK WITH. THE TIMING ISSUES BETWEEN THE MODELS
APPEAR TO BECOMING LESS WITH THE TREND GOING TOWARD THE FASTER
NAM. ACCORDING TO THE 29.00Z NAM...THE MAIN LIFT IS IN THE LOW
LEVELS AHEAD OF THE COLD FRONT AHEAD OF WHEN THE MID LEVEL TROUGH
MOVES IN...SO THERE SHOULD NOT BE MUCH UPPER LEVEL INFLUENCE HERE.
INSTABILITY IS DECENT IN THE 1000-2000 J/KG RANGE WITH THE NAM/GFS
LIKELY OVER-FORECASTING THE SBCAPE DUE THEIR SURFACE DEW POINTS
BEING IN THE UPPER 60S TO LOW 70S WHEN WE WILL MORE LIKELY BE IN
THE MID 60S. 29.00Z NAM FORECAST SOUNDINGS WOULD ALSO SUGGEST THAT
THE ATMOSPHERE IS CAPPED FROM AN INVERSION AROUND 750MB THAT WOULD
STRENGTHEN WITH LOWER SFC DEW POINTS. BASED ON THIS...HAVE FOCUSED
THE BETTER CHANCES TO CENTRAL WISCONSIN WHERE THE COMBINATION OF
FORCING AND LESS OF A CAP MAY LEAD TO SOME CONVECTION BUT HAVE
LEFT SOME SLIGHT CHANCES IN TO THE SOUTHWEST ALONG THE FRONT.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
306 AM CDT SUN JUL 29 2012
NOT MUCH CONFIDENCE IN THE LATER PART OF THE WEEK WITH THE UPPER
LEVEL FLOW EXPECTED TO BECOME MORE ZONAL TOWARD NEXT WEEKEND.
SURFACE HIGH PRESSURE WILL BE IN PLACE WEDNESDAY BEFORE A COLD
FRONT DROPS DOWN INTO THE REGION WEDNESDAY NIGHT AND THURSDAY.
THIS FRONT THEN APPEARS TO STALL OUT ACROSS THE REGION WHICH KEEPS
PRECIPITATION CHANCES AROUND THROUGH THE REST OF THE WEEK. SOME
TIMING DIFFERENCES WITH THE FRONT VIA THE 29.00Z GFS/ECMWF LEADS
TO HAVING THE CHANCES THROUGH THE WEEK THOUGH THERE WILL LIKELY BE
SOME BREAKS AT TIMES. TEMPERATURE-WISE IT STILL LOOKS FAIRLY
SEASONAL WITH NOT MUCH IN THE WAY OF CHANGES DUE TO WEAK LOW LEVEL
WARM AIR ADVECTION.
&&
.AVIATION...THROUGH 06Z MONDAY
1149 PM CDT SAT JUL 28 2012
CONTINUED THE PESSIMISTIC TREND OF MVFR CIGS/VSBYS AT KRST AND
TEMPO MVFR CIGS AT KLSE. CONFIDENCE IS HIGHER THAT A WEATHER
SYSTEM MOVING FROM ERN SD WILL MOVE IN AND DEVELOP SHRA OVERNIGHT
HOWEVER JUST HOW LOW THE CIG/VSBY WILL GET AT THE SITES IS OF
LOWER CONFIDENCE. THERE MAY ALSO BE THUNDER NEAR/AT THE TAF
HOWEVER THE CONFIDENCE IS LOW ON THIS OCCURRENCE AS THE INSTABILITY
IS ONLY IN THE 100-300 J/KG RANGE AND THE HIGH RESOLUTION MODEL
GUIDANCE DOESNT KEEP TSRA ACTIVITY FAR ENOUGH EAST TO AFFECT TAF
SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 AM CDT SUN JUL 29 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1151 PM MDT MON JUL 30 2012
.UPDATE...
ADDED SHOWERS AND THUNDERSTORMS FOR THE FORECAST THROUGH 5 AM FOR
MOST OF SOUTHERN COLORADO WITH THE HEAVIEST ACTIVITY OVER THE
CENTRAL MOUNTAINS...TO THE PALMER DIVIDE...AND THE FAR EASTERN
PLAINS. ANOTHER HALF AN INCH OF PRECIP IS POSSIBLE WITH LOCALLY
HIGHER AMOUNTS POSSIBLE. MOZLEY
&&
.PREV DISCUSSION... /ISSUED 1121 PM MDT MON JUL 30 2012/
AVIATION...
THUNDERSTORM ACTIVITY CONTINUES TO MOVE ACROSS KCOS AND WILL DO SO
THROUGH 08Z. GUSTY OUTFLOW WINDS TO NEAR 35 KTS...AND REDUCED VIS
AND CIGS TO IFR ARE LIKELY AS THE THUNDERSTORMS PASS.
ANOTHER ROUND OF THUNDERSTORMS ARE FORECAST TO DEVELOP OVER THE
MOUNTAINS BY TUESDAY AFTERNOON AND IMPACT KCOS AND KPUB. GUSTY
OUTFLOW WINDS WILL BE THE MAIN THREAT WITH THESE THUNDERSTORMS.
ANY STORMS THAT PASS OVER THE TERMINALS WILL LIKELY PRODUCE
REDUCED VIS AND CIGS. 88
PREV DISCUSSION... /ISSUED 323 PM MDT MON JUL 30 2012/
SHORT TERM...
(TONIGHT AND TUESDAY)
.MORE INTENSE THUNDERSTORMS TODAY BRINGING THREAT OF HEAVY RAIN TO
PORTIONS OF SOUTH CENTRAL AND SOUTHEAST COLORADO...
UPPER HIGH TO THE SOUTH CONTINUES TO NUDGE THE MAIN TAP OF THE
MONSOON PLUME FARTHER WEST AND NORTH...HOWEVER...YESTERDAY`S FRONT
HAS COMPENSATED SOME WITH AN INCREASE IN LOW LEVEL MOISTURE. THIS
HAS RESULTED IN HIGHER CAPES TODAY ACROSS THE SOUTHEAST
MTS/PLAINS...AND STORMS ON RADAR HAVE DEFINITELY BEEN STRONGER.
CAPE VALUES OFF SPC MESONET SHOWING VALUES SHOWING AROUND 1000-2000
J/KG...THOUGH WITH A LITTLE MIXING...THEY MAY DROP BACK TO AROUND
1000-1500 J/KG. DEEP LAYER SHEARS ARE RUNNING AROUND 20-30KTS...SO
SHOULD NOT LOOKING AT A WIDESPREAD SEVERE RISK...BUT CERTAINLY SOME
STORMS COULD PULSE UP AND PRODUCE HAIL TO AROUND 1 INCH IN
DIAMETER...ESPECIALLY OVER/NEAR THE HIGHER TERRAIN. HRRR BRINGS SEVERAL WAVES
OF THUNDERSTORMS OFF THE SOUTHEAST MTS...PARTICULARLY ACROSS THE
PIKES PEAK REGION WITH THUNDERSTORMS SPREADING OFF INTO THE
SOUTHEAST PLAINS DURING THE EVENING. STORM MOTIONS OFF RADAR HAVE
BEEN TO THE EAST NORTHEAST AROUND 10-15 MPH...HOWEVER WITH CONTINUAL
REGENERATION...IF STORMS TRACK OVER THE SAME LOCATION...LOCALLY
HEAVY RAINFALL WITH THE POTENTIAL FOR FLASH FLOODING WILL BE A
CONCERN...ESPECIALLY FOR THE WALDO CANYON BURN SCAR. ONE STORM HAS ALREADY
COME FAIRLY CLOSE...THOUGH JUST MISSED TO THE SOUTH. HRRR SHOWS
ANOTHER LINE OF THUNDERSTORMS MOVING OFF THE PIKES PEAK REGION AND
POTENTIAL AFFECTING THE BURN SCAR AROUND 22-23Z. GIVEN THAT STORMS
ARE STRONGER TODAY...AND CAPABLE OF HIGHER RAINFALL RATES (UP TO 1.5
INCH PER HOUR)...FLOODING ON THE WALDO CANYON BURN SCAR IS A GREATER
CONCERN. HOWEVER...STORMS WILL STILL BE HIT OR MISS...SO CLOSE
MONITORING OF THE BURN SCAR WILL CONTINUE.
FOR TONIGHT...MODELS IN GENERAL AGREEMENT SPREADING THUNDERSTORMS
EASTWARD ACROSS THE PLAINS THROUGH THE EVENING BEFORE DIMINISHING
TOWARDS MORNING. TUESDAY LOOKS LIKE A SIMILAR EVENT TO TODAY...WITH
LOW LEVEL MOISTURE STILL IN PLACE...BUT MAIN MONSOON PLUME SHIFTED
FARTHER WEST AND NORTH. MAIN TRACK OF ANY SHORTWAVES AROUND THE
PERIPHERY OF THE UPPER RIDGE MAY BE FARTHER NORTH AS WELL...BUT WITH
CONVECTIVE HEATING...MODELS BREAK OUT ANOTHER ROUND OF SCATTERED
THUNDERSTORMS ACROSS THE MOUNTAINS AREAS...WITH GREATEST COVERAGE
ACROSS THE SOUTHEAST MTS. CAPES WILL PROBABLY END UP BEING SIMILAR
TODAY...SO SMALL HAIL AND HEAVY RAINFALL WILL BE THE PRIMARY
THREATS. FLASH FLOODING ON THE WALDO CANYON BURN SCAR WILL BE A
CONCERN ONCE AGAIN.
LONG TERM...
(TUESDAY NIGHT THROUGH NEXT MONDAY)
TEMPERATURES AND POPS ARE THE PRIMARY METEOROLOGICAL ISSUES DURING
THE LONGER TERM. RECENT COMPUTER MODELS SUGGEST THAT UPPER HIGH
CENTERED OVER THE TEXAS PANHANDLE AT 00Z WEDNESDAY ATTEMPTS TO SLOWLY
SHIFT INTO CENTRAL OKLAHOMA BY 12Z SATURDAY BEFORE PUSHING BACK
INTO THE TEXAS PANHANDLE REGION BY NEXT MONDAY.
FAVORABLE ATMOSPHERIC MOISTURE/HIGH PRECIPITABLE WATER VALUES/MONSOONAL
PLUME ROTATING AROUND THE UPPER HIGH WILL CONTINUE TO IMPACT THE
FORECAST DISTRICT AT TIMES THROUGH THE LONGER TERM. IN
ADDITION...INCREASING SHORT-WAVE ACTIVITY AS WELL AS SEVERAL
NORTHERLY SURGES ARE PROJECTED TO IMPACT THE FORECAST DISTRICT AT
TIMES FROM TUESDAY NIGHT INTO AT LEAST THE UPCOMING WEEKEND.
AS DISCUSSED DURING PREVIOUS DISCUSSIONS...ISOLATED TO SCATTERED
PRIMARILY AFTERNOON AND EVENING THUNDERSTORMS(SOME CONTAINING
LOCALLY HEAVY RAIN AND HAIL) ARE ANTICIPATED OVER MANY SECTIONS OF
THE FORECAST DISTRICT AT TIMES DURING THE LONGER TERM.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND
FLASH FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS
THE WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
FINALLY...MAXIMUM AND MINIMUM TEMPERATURES DURING THE LONGER TERM
SHOULD CONTINUE TO RUN AT TO ABOVE EARLY AUGUST CLIMATOLOGICAL
AVERAGES IN COMBINATION WITH GENERALLY LOW-GRADE GRADIENT WINDS.
AVIATION...
TSRA WILL BE MOST LIKELY TO IMPACT THE COS TAF SITE THIS
EVENING...WITH HEAVY RAIN...AND ERRATIC GUSTY WINDS UP TO 45 KTS THE
PRIMARY THREAT. SOME SMALL HAIL WILL ALSO BE POSSIBLE. LESS OF A
CHANCE FOR -TSRA TO AFFECT THE KPUB AND KALS TAF SITE...SO WILL
MAINTAIN VCTS IN TAFS THERE. WINDS SHOULD SHIFT OUT OF THE NORTH TO
NORTHWEST WITH CONVECTIVE OUTFLOWS SPREADING OFF THE MOUNTAINS
DURING THE 23-00Z TIME FRAME FOR KCOS AND KPUB. WINDS AND
THUNDERSTORMS SHOULD DIMINISH THROUGH THE EVENING. ANOTHER ROUND OF
THUNDERSTORMS WILL BE POSSIBLE AGAIN ON TUESDAY...WITH KCOS UNDER
THE GREATEST RISK FOR -TSRA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
88/40
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1121 PM MDT MON JUL 30 2012
.AVIATION...
THUNDERSTORM ACTIVITY CONTINUES TO MOVE ACROSS KCOS AND WILL DO SO
THROUGH 08Z. GUSTY OUTFLOW WINDS TO NEAR 35 KTS...AND REDUCED VIS
AND CIGS TO IFR ARE LIKELY AS THE THUNDERSTORMS PASS.
ANOTHER ROUND OF THUNDERSTORMS ARE FORECAST TO DEVELOP OVER THE
MOUNTAINS BY TUESDAY AFTERNOON AND IMPACT KCOS AND KPUB. GUSTY
OUTFLOW WINDS WILL BE THE MAIN THREAT WITH THESE THUNDERSTORMS.
ANY STORMS THAT PASS OVER THE TERMINALS WILL LIKELY PRODUCE
REDUCED VIS AND CIGS. MOZLEY
&&
.PREV DISCUSSION... /ISSUED 323 PM MDT MON JUL 30 2012/
SHORT TERM...
(TONIGHT AND TUESDAY)
..MORE INTENSE THUNDERSTORMS TODAY BRINGING THREAT OF HEAVY RAIN TO
PORTIONS OF SOUTH CENTRAL AND SOUTHEAST COLORADO...
UPPER HIGH TO THE SOUTH CONTINUES TO NUDGE THE MAIN TAP OF THE
MONSOON PLUME FARTHER WEST AND NORTH...HOWEVER...YESTERDAY`S FRONT
HAS COMPENSATED SOME WITH AN INCREASE IN LOW LEVEL MOISTURE. THIS
HAS RESULTED IN HIGHER CAPES TODAY ACROSS THE SOUTHEAST
MTS/PLAINS...AND STORMS ON RADAR HAVE DEFINITELY BEEN STRONGER.
CAPE VALUES OFF SPC MESONET SHOWING VALUES SHOWING AROUND 1000-2000
J/KG...THOUGH WITH A LITTLE MIXING...THEY MAY DROP BACK TO AROUND
1000-1500 J/KG. DEEP LAYER SHEARS ARE RUNNING AROUND 20-30KTS...SO
SHOULD NOT LOOKING AT A WIDESPREAD SEVERE RISK...BUT CERTAINLY SOME
STORMS COULD PULSE UP AND PRODUCE HAIL TO AROUND 1 INCH IN
DIAMETER...ESPECIALLY OVER/NEAR THE HIGHER TERRAIN. HRRR BRINGS SEVERAL WAVES
OF THUNDERSTORMS OFF THE SOUTHEAST MTS...PARTICULARLY ACROSS THE
PIKES PEAK REGION WITH THUNDERSTORMS SPREADING OFF INTO THE
SOUTHEAST PLAINS DURING THE EVENING. STORM MOTIONS OFF RADAR HAVE
BEEN TO THE EAST NORTHEAST AROUND 10-15 MPH...HOWEVER WITH CONTINUAL
REGENERATION...IF STORMS TRACK OVER THE SAME LOCATION...LOCALLY
HEAVY RAINFALL WITH THE POTENTIAL FOR FLASH FLOODING WILL BE A
CONCERN...ESPECIALLY FOR THE WALDO CANYON BURN SCAR. ONE STORM HAS ALREADY
COME FAIRLY CLOSE...THOUGH JUST MISSED TO THE SOUTH. HRRR SHOWS
ANOTHER LINE OF THUNDERSTORMS MOVING OFF THE PIKES PEAK REGION AND
POTENTIAL AFFECTING THE BURN SCAR AROUND 22-23Z. GIVEN THAT STORMS
ARE STRONGER TODAY...AND CAPABLE OF HIGHER RAINFALL RATES (UP TO 1.5
INCH PER HOUR)...FLOODING ON THE WALDO CANYON BURN SCAR IS A GREATER
CONCERN. HOWEVER...STORMS WILL STILL BE HIT OR MISS...SO CLOSE
MONITORING OF THE BURN SCAR WILL CONTINUE.
FOR TONIGHT...MODELS IN GENERAL AGREEMENT SPREADING THUNDERSTORMS
EASTWARD ACROSS THE PLAINS THROUGH THE EVENING BEFORE DIMINISHING
TOWARDS MORNING. TUESDAY LOOKS LIKE A SIMILAR EVENT TO TODAY...WITH
LOW LEVEL MOISTURE STILL IN PLACE...BUT MAIN MONSOON PLUME SHIFTED
FARTHER WEST AND NORTH. MAIN TRACK OF ANY SHORTWAVES AROUND THE
PERIPHERY OF THE UPPER RIDGE MAY BE FARTHER NORTH AS WELL...BUT WITH
CONVECTIVE HEATING...MODELS BREAK OUT ANOTHER ROUND OF SCATTERED
THUNDERSTORMS ACROSS THE MOUNTAINS AREAS...WITH GREATEST COVERAGE
ACROSS THE SOUTHEAST MTS. CAPES WILL PROBABLY END UP BEING SIMILAR
TODAY...SO SMALL HAIL AND HEAVY RAINFALL WILL BE THE PRIMARY
THREATS. FLASH FLOODING ON THE WALDO CANYON BURN SCAR WILL BE A
CONCERN ONCE AGAIN.
LONG TERM...
(TUESDAY NIGHT THROUGH NEXT MONDAY)
TEMPERATURES AND POPS ARE THE PRIMARY METEOROLOGICAL ISSUES DURING
THE LONGER TERM. RECENT COMPUTER MODELS SUGGEST THAT UPPER HIGH
CENTERED OVER THE TEXAS PANHANDLE AT 00Z WEDNESDAY ATTEMPTS TO SLOWLY
SHIFT INTO CENTRAL OKLAHOMA BY 12Z SATURDAY BEFORE PUSHING BACK
INTO THE TEXAS PANHANDLE REGION BY NEXT MONDAY.
FAVORABLE ATMOSPHERIC MOISTURE/HIGH PRECIPITABLE WATER VALUES/MONSOONAL
PLUME ROTATING AROUND THE UPPER HIGH WILL CONTINUE TO IMPACT THE
FORECAST DISTRICT AT TIMES THROUGH THE LONGER TERM. IN
ADDITION...INCREASING SHORT-WAVE ACTIVITY AS WELL AS SEVERAL
NORTHERLY SURGES ARE PROJECTED TO IMPACT THE FORECAST DISTRICT AT
TIMES FROM TUESDAY NIGHT INTO AT LEAST THE UPCOMING WEEKEND.
AS DISCUSSED DURING PREVIOUS DISCUSSIONS...ISOLATED TO SCATTERED
PRIMARILY AFTERNOON AND EVENING THUNDERSTORMS(SOME CONTAINING
LOCALLY HEAVY RAIN AND HAIL) ARE ANTICIPATED OVER MANY SECTIONS OF
THE FORECAST DISTRICT AT TIMES DURING THE LONGER TERM.
AS ALWAYS...PLEASE REMEMBER THAT THE STRONGER STORMS DURING THE
LONGER TERM WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAIN AND
FLASH FLOODING POTENTIAL(ESPECIALLY OVER BURN SCAR REGIONS SUCH AS
THE WALDO CANYON BURN SCAR). WFO PUEBLO WILL CONTINUE TO MONITOR
CLOSELY.
FINALLY...MAXIMUM AND MINIMUM TEMPERATURES DURING THE LONGER TERM
SHOULD CONTINUE TO RUN AT TO ABOVE EARLY AUGUST CLIMATOLOGICAL
AVERAGES IN COMBINATION WITH GENERALLY LOW-GRADE GRADIENT WINDS.
AVIATION...
TSRA WILL BE MOST LIKELY TO IMPACT THE COS TAF SITE THIS
EVENING...WITH HEAVY RAIN...AND ERRATIC GUSTY WINDS UP TO 45 KTS THE
PRIMARY THREAT. SOME SMALL HAIL WILL ALSO BE POSSIBLE. LESS OF A
CHANCE FOR -TSRA TO AFFECT THE KPUB AND KALS TAF SITE...SO WILL
MAINTAIN VCTS IN TAFS THERE. WINDS SHOULD SHIFT OUT OF THE NORTH TO
NORTHWEST WITH CONVECTIVE OUTFLOWS SPREADING OFF THE MOUNTAINS
DURING THE 23-00Z TIME FRAME FOR KCOS AND KPUB. WINDS AND
THUNDERSTORMS SHOULD DIMINISH THROUGH THE EVENING. ANOTHER ROUND OF
THUNDERSTORMS WILL BE POSSIBLE AGAIN ON TUESDAY...WITH KCOS UNDER
THE GREATEST RISK FOR -TSRA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
88/40
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
114 AM CDT TUE JUL 31 2012
.DISCUSSION...
310 PM CDT
SHORT TERM...THIS EVENING THROUGH THURSDAY...
PRIMARY CONCERN IS CONVECTIVE CHANCES THIS EVENING ACROSS NORTHERN
ILLINOIS. WATER VAPOR IMAGERY TODAY SHOWS STRONG MIDLEVEL RIDGING
CENTERED OVER THE SOUTHERN PLAINS AND A FAIRLY STRONG SHORTWAVE
TROUGH OVER ONTARIO...WITH ANOTHER TROUGH OFF THE PACIFIC NORTHWEST
COAST. THE TROUGH OVER ONTARIO WILL DIG SOUTHEAST...WITH ASSOCIATED
SURFACE LOW DRAGGING COOL FRONT ACROSS LAKE MICHIGAN AND ACROSS CWA
THIS EVENING THROUGH TONIGHT.
THIS EVENING...THOUGH THE BEST FORCING IN TERMS OF POSITIVE
VORTICITY ADVECTION WILL BE FOCUSED NORTHEAST OF THE CWA CLOSER TO
THE TROUGH AXIS...IT APPEARS THERE WILL BE DECENT CONVERGENCE ALONG
AND AHEAD OF THE COOL FRONT...ALONG WITH 0-6 KM BULK SHEAR VALUES
INCREASING TO 30 TO 35 KT AND NORTHERN ILLINOIS BEING IN THE EXIT
REGION OF AN ~80 KT UPPER LEVEL JET STREAK. SO THERE IS SOME SUPPORT
FOR ORGANIZED UPDRAFTS. SUSPECT THAT THE MLCAPE BEING PROGGED THIS
BY THE NAM AND RAP ACROSS FAR NORTHERN IL...IN EXCESS OF 2500 J/KG
IS A BIT OVERDONE BECAUSE FCST SURFACE TEMPS AND DEWPOINTS ARE
LIKELY A BIT TOO HIGH...BUT THERE SHOULD STILL BE AT LEAST 1500 J/KG
TO TAP INTO...WITH MINIMAL CIN. WITH TEMPERATURES ONLY SLOWLY
COOLING AHEAD OF THE FRONT...LOW LEVEL LAPSE RATES ARE EXPECTED TO
REMAIN FAIRLY STEEP AND DRY AIR IN THE LOWER LEVELS MAY SUPPORT
DCAPE VALUES IN EXCESS OF 1000 J/KG. THUS PRIMARY THREAT WITH ANY
TSRA IS EXPECTED TO BE DAMAGING WIND GUSTS...THOUGH THE GOOD DEEP
LAYER SHEAR COULD ALSO ALLOW FOR AT LEAST MARGINALLY SEVERE HAIL.
HAVE INCREASED POPS JUST A BIT ALONG AND NORTH OF I-80...THOUGH
STILL EXPECTING SCATTERED COVERAGE AT MOST...WITH EARLY EVENING
POPS CONFINED TO CLOSER TO THE WISCONSIN BORDER...SPREADING INTO
THE CHICAGO AREA LATER IN THE EVENING. DIURNAL DECREASE IN
INSTABILITY LATER THIS EVENING AND OVERNIGHT WILL LIKELY LEND TO
DECREASE IN INTENSITY AND COVERAGE OF CONVECTION. WILL MAINTAIN
LOW POPS FOR ISOLATED SHRA/TSRA AFTER MIDNIGHT AS THE FRONT PUSHES
THROUGH. KEPT THE INHERITED SLIGHT POPS TUESDAY MORNING PORTIONS
OF NORTHWEST INDIANA MAINLY EAST OF I-65...WITH THE FRONT EXPECTED
TO ON THE DOORSTEP BY THAT TIME. THE THING TO WATCH FOR WOULD BE A
SLOWER FRONTAL TIMING...WHICH MAY ALLOW SOME INSTABILITY TO
REBUILD AND PRESENT SOME OPPORTUNITY FOR THE FAR SOUTHEAST CWA TO
SEE TSRA LATE MORNING/EARLY AFTERNOON. FOR NOW...DO NOT THINK THIS
IS A LIKELY SCENARIO AND HAVE THE WHOLE CWA DRY AFTER 15Z TUESDAY.
HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON TUESDAY...WITH
NORTHERLY WINDS...THOUGH THE AIR MASS REALLY WONT BE MUCH COOLER.
AREAS AWAY FROM THE LAKE SHOULD ACTUALLY REACH NEAR OR A BIT ABOVE
90 UNDER FULL SUN...WITH ONSHORE WINDS KEEPING THE LAKEFRONT IN THE
MID 80S. THE MOST NOTICEABLE DIFFERENCE BEHIND THE FRONT IS EXPECTED
TO BE A DRIER AIR MASS. THUS DESPITE ABOVE NORMAL TEMPERATURES...THE
NORTHERLY BREEZE AND MANAGEABLE HUMIDITY LEVELS WILL MAKE IT A
FAIRLY COMFORTABLE DAY...ESPECIALLY CONSIDERING ALL THE EXTREME HEAT
WEVE SEEN THIS SUMMER. WEDNESDAY WILL BE SIMILARLY WARM AND
SUNNY...EXCEPT WITH MUCH LIGHTER WINDS WITH HIGH PRESSURE OVERHEAD. IF
WINDS ARENT ONSHORE TO START TO THE DAY ALONG THE LAKEFRONT...A LAKE
BREEZE SHOULD BE ABLE TO GET GOING QUICKLY WITH SUCH LIGHT FLOW OVER
THE AREA. THIS WILL AGAIN LIMIT HIGH TEMPERATURES A BIT ALONG THE
LAKESHORE.
THURSDAY PRESENTS A MORE INTERESTING SCENARIO IN TERMS OF THE HIGH
TEMPERATURE FORECAST. THE CWA WILL NOT BE IN A FAVORED AREA WITH
REGARD TO THE POSITION OF THE CENTER OF THE MIDLEVEL RIDGE...WHICH
WILL STILL BE OVER THE SOUTHERN PLAINS. HOWEVER...AN 850 MB THERMAL
RIDGE WILL PUSH INTO THE AREA WITH WARM ADVECTION BRINGING 850 MB
TEMPS TO HIGHER THAN 20C BY THE AFTERNOON...SUCH AS ON THE WELL
PERFORMING ECMWF MODEL. WITH FULL SUN AND DEEP MIXING...THIS WOULD
SUPPORT HOT TEMPERATURES IN THE MID AND UPPER 90S. HOWEVER...BOTH
THE NAM AND ECMWF...WHICH HAVE THE HOTTEST MAX TEMPS FCST...ALSO
SUGGEST FAIRLY HIGH RH AT THE MID AND UPPER LEVELS...WHICH COULD BE
IN THE FORM OF CONVECTIVE MID AND HIGH CLOUD DEBRIS. THINK CLOUDS
WILL BE THE LIMITING FACTOR FOR TEMPS ON THURSDAY...BUT WITH THE
VERY WARM THERMAL PROFILES...RAISED TEMPS A FEW DEGREES FROM
INHERITED TO MAINLY LOW 90S. IF THERE IS LESS CLOUD
COVER...CERTAINLY COULD SEE THE HOTTER TEMPS REALIZED. ALSO...WINDS
ALOFT ARE EXPECTED TO BE WEAK ENOUGH TO ALLOW FOR A LATE DAY LAKE
BREEZE TO PUSH INLAND...WHICH MAY BRING SOME MINOR COOLING.
FORCING FOR CONVECTION LOOKS RATHER WEAK AND MAINLY THURSDAY
AFTERNOON...WITH SHORT WAVE MOVING TO NORTH AND WEAK COOL FRONT
STARTING TO DROP INTO AREA...BUT WILL MAINTAIN INHERITED SLIGHT POPS
FOR NOW FOR SHRA/TSRA. MOST OF THE AREA WILL LIKELY REMAIN DRY.
RC
LONG TERM...THURSDAY EVENING THROUGH MONDAY..
SHORT WAVE MOVING THROUGH THE NORTHERN GREAT LAKES THU EVENING WITH
ASSOCIATED WEAK SURFACE TROF/FRONT DROPPING INTO NORTHERN
IL/NORTHWEST IN. WITH BEST FORCING FURTHER NORTH AND ONLY WEAK
SURFACE CONVERGENCE...AND CONSIDERING STRENGTH OF ONGOING
DROUGHT...WILL ONLY CARRY 20-30 PCT POPS. REMNANTS OF FRONT THEN
HANG UP OVER THE AREA FRIDAY BUT AGAIN WITH ONLY WEAK LOW LEVEL
CONVERGENCE AND NO UPPER LEVEL SUPPORT...WILL JUST MAINTAIN SLIGHT
CHANCE POPS FOR FRIDAY. GFS PUSHES FRONT THROUGH AND DEVELOPS EAST
WINDS OVER THE AREA FRIDAY WHILE ECMWF HAS A WEAK WISHY WASHY
SURFACE PATTERN. EITHER WAY LAKE BREEZE LIKELY TO KEEP TEMPS IN LOW
TO MID 80S LAKEFORNT BUT NEAR 90 SOUTH TOWARDS PONTIAC.
MEANWHILE MUCH MORE POTENT TROF/UPPER LOW BARRELS INTO WESTERN
CANADA COAST WED AND PLOWS THROUGH NORTHERN ROCKIES AND INTO THE
NORTHERN PLAINS THU AND FRI. THIS WILL ACT TO SHOVE UPPER RIDGE AND
ASSOCIATED HEAT DOME EASTWARD INTO THE MIDWEST AND GREAT LAKES BY
SATURDAY. SOUTHWEST FLOW AHEAD OF APPROACHING TROF PUSHES 850 TEMPS
TO AROUND 22C SATURDAY. WITH UNCERTAINTY ON CLOUD COVER HESITANT TO
RAISE TEMPS TOO MUCH. WILL GO WITH TEMPS IN LOWER 90S BUT MID TO
UPPER 90S NOT OUT OF THE QUESTION IF WE GET ENOUGH SUN. BEST CHANCE
OF WIDESPREAD RAIN IN A LONG TIME SAT AFTN AND EVENING AS STRONG
UPPER TROF/UPPER LOW MOVES THROUGH THE GREAT LAKES AND STRONG COLD
FRONT PUSHES THROUGH THE AREA. 12Z ECMWF A BITY SLOWER ON ARRIVAL OF
FRONT AND THUNDERSTORMS...MORE LIKELY SAT NIGHT INTO SUN MORNING.
TURNING COOLER AND DRIER SUN AND MON.
ALLSOPP
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* TSRA PSBL BTWN 08 AND 10Z.
* SW WINDS BECOME NW IN THE PRE DAWN HOURS...AND THEN BECOME N BY
NOON.
* LAKE BREEZE LIKELY IN THE MID AFTERNOON SHIFTING WINDS TO ENE OR E.
JEE
//DISCUSSION...UPDATED 06Z...
A LINE OF THUNDERSTORMS EXTENDS FROM GRAND HAVEN MI THROUGH SOUTH
CENTRAL WI. IN GENERAL THE LINE IS MOVING SE AROUND 35 KT...WITH
RFD...ORD...AND DPA HAVING THE BEST CHANCE OF TSRA MOVING OVERHEAD.
AS SUCH PUT TWO HOUR TEMPOS IN FOR TSRA. MAIN THREATS FROM THE
TSRA WILL BE FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY
DOWNPOURS...AND 30 TO 40 KT WIND GUSTS. EXPECTING TS TO WEAKEN AS
THEY ENTER NORTHERN ILLINOIS THEREFORE NOT AS CONFIDENT THAT A
TSRA WILL IMPACT MDW OR GYY...BUT KEPT A VCTS IN PLACE FOR BOTH
LOCATIONS SINCE TSRA WILL PROBABLY BE IN THE AREA.
THE COLD FRONT THAT IS SUPPORTING THESE THUNDERSTORMS WILL PASS
THROUGH THE REGION CLOSELY BEHIND THE TSRA. WINDS WILL SHIFT TO NW
BEHIND THE FRONT AND MID LEVEL CLOUDS WILL THIN TO SCT. WINDS WILL
CONTINUE TO TURN TO THE N BY NOON WITH A LAKE BREEZE LIKELY IN THE
MID AFTERNOON. CURRENTLY HAVE THE LAKE BREEZE TURNING ORD AND MDW
WINDS ENE TO E AT 21Z...BUT NOT ENTIRELY CONFIDENT WITH THAT
TIMING. SKIES CLEAR AND WINDS DIMINISH AS HIGH PRESSURE MOVES IN
FROM THE NORTH.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN TIMING OF TSRA AT ORD...MEDIUM CONFIDENCE
WITH VCTS AT MDW.
* HIGH CONFIDENCE IN CIG VALUES AND TRENDS.
* HIGH CONFIDENCE IN WIND TRENDS...MEDIUM CONFIDENCE WITH TIMING
OF LAKE BREEZE.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY THROUGH SATURDAY...VFR. CHC SHRA/TSRA W/PATCHY MVFR CIGS.
SUNDAY...VFR.
BEACHLER
&&
.MARINE...
226 PM CDT
LOW PRESSURE MOVING ACROSS SOUTHERN ONTARIO...WILL DRAG A COLD FRONT
DOWN THE LAKE TONIGHT. SOME STRONG TO SEVERE THUNDERSTORMS COULD
OCCUR ACROSS THE LAKE THIS EVENING AHEAD OF THE FRONT. ONCE THE
FRONT PASSES THE WINDS WILL SWITCH OUT OF THE NORTH UP TO 25 KT.
THESE STRONGER WINDS WILL CONTINUE ACROSS THE SOUTH HALF OF THE LAKE
DURING THE DAY ON TUESDAY. WAVES OVER 4 FEET ARE POSSIBLE ALONG THE
INDIANA NEAR SHORE WATERS. THIS COULD RESULT IN HAZARDS TO SMALL
CRAFT FOR TUESDAY EVENING THROUGH WEDNESDAY MORNING. HIGH PRESSURE
WILL BUILD IN ACROSS THE LAKE TUESDAY NIGHT INTO WEDNESDAY. THIS
WILL RESULT IN ABATING WINDS FOR A PERIOD TUESDAY NIGHT INTO
WEDNESDAY.
THE WINDS LOOK TO TURN SOUTHERLY AT 10 TO 20 KT AGAIN BY THURSDAY AS
THE SURFACE HIGH SHIFTS EASTWARD ACROSS THE OHIO VALLEY. ANOTHER
AREA OF LOW PRESSURE MAY PUSH ANOTHER COLD FRONT ACROSS THE LAKE
LATE THURSDAY AND THURSDAY NIGHT...BRINGING ANOTHER PUSH OF NORTHERLY
FLOW DOWN THE LAKE. IN THE EXTENDED PERIOD IT APPEARS THAT A
STRONGER STORM SYSTEM MAY MOVE ACROSS THE UPPER MIDWEST AND GREAT
LAKES REGION OVER THE WEEKEND. THIS COULD PRODUCE A PERIOD OF
STRONGER WINDS ACROSS THE LAKE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HIGH RIP CURRENT RISK...ILZ014...10 AM TUESDAY TO 10 AM
WEDNESDAY.
IN...HIGH RIP CURRENT RISK...INZ001-INZ002...10 AM TUESDAY TO 10 AM
WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...4 PM
TUESDAY TO 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1247 AM CDT TUE JUL 31 2012
...UPDATED FOR AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 1158 AM CDT MON JUL 30 2012
AN UPPER LEVEL HIGH CONTINUED TO GRIP THE CENTRAL AND SOUTHERN GREAT
PLAINS. THE CENTER OF THE HIGH AT 500MB WAS LOCATED ACROSS THE
SOUTHERN TEXAS PANHANDLE PER RAOB AND RAP ANALYSIS AS OF 30.12Z. AN
ARC OF MID LEVEL MOISTURE COULD BE SEEN ON WATER VAPOR LOOP AND RAOB
ANALYSIS FROM WESTERN/CENTRAL ARIZONA THROUGH UTAH AND NORTHEAST TO
SOUTHEASTERN WYOMING AND WESTERN NEBRASKA. ALL ALONG THIS MOISTURE
ARC...THERE WERE MINOR MID LEVEL PERTURBATIONS IN THE FLOW PATTERN
DUE TO LATENT HEAT RELEASE FROM VARIOUS THUNDERSTORM CLUSTERS. A
MESOSCALE CONVECTIVE SYSTEM MOVED ACROSS SOUTHERN NEBRASKA/NORTHERN
KANSAS DURING THE OVERNIGHT HOURS WITH THE MID LEVEL POTENTIAL
VORTICITY ANOMALY TIED TO THIS MCS MOVING INTO EASTERN KS/WESTERN
MO. ADDITIONAL MID LEVEL VORTICITY COULD BE SEEN IN THE RAP ANALYSIS
MOVING INTO NORTHERN COLORADO WITH A 30-40 KNOT 400MB SPEED MAX
ROTATING NORTH-NORTHEASTWARD INTO THE COLORADO ROCKIES. IN THE LOWER
TROPOSPHERE...A STATIONARY FRONT EXTENDED FROM ROUGHLY BEAVER, OK TO
BUCKLIN, KS TO NEAR PRATT, KS AT 16Z. OKLAHOMA MESONET OBSERVATIONS
AT 1650Z REVEALED AN AXIS OF 102 TO 104F TEMPERATURES ACROSS
WEST-CENTRAL OKLAHOMA ON WEST-SOUTHWEST SURFACE WINDS SOUTH OF THIS
BOUNDARY.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 244 PM CDT MON JUL 30 2012
WITH THE AFTERNOON FORECAST UPDATE...WILL LOWER THE POPS DOWN TO
10-14 PERCENT FOR AREAS ALONG THE STATIONARY FRONT AS CONVERGENCE
ALONG THE FRONT IS QUITE WEAK AND THERE HAS BEEN A LACK OF CUMULUS
DEVELOPMENT THROUGH 1930Z. IF ANYTHING DOES DEVELOP...THE COVERAGE
WILL BE VERY ISOLATED AND ANY INDIVIDUAL STORM WILL BE SMALL. WILL
BE TURNING THE ATTENTION TO THE WEST LATER ON THIS EVENING AND
DURING THE OVERNIGHT HOURS AS AN MCS MAY DEVELOP IN THE POST-FRONTAL
LIGHT UPSLOPE WINDS WITH DEWPOINTS IN THE MID TO UPPER 50S ACROSS
EAST-CENTRAL COLORADO AND WEST-CENTRAL/SOUTHWEST KANSAS ALONG AND
NORTH OF THE FRONT. VARIOUS HIGH-RESOLUTION CONVECTION-ALLOWING
MODELS SUGGEST HIGHER TERRAIN STORMS WILL MANAGE TO HOLD TOGETHER TO
THE KANSAS STATE BORDER...SO WILL HAVE 30 POPS GOING ACROSS THE
WESTERN COUNTIES AND 20 POPS AS FAR EAST AS ROUGHLY HIGHWAY 83.
LATE TONIGHT INTO TOMORROW...THE CONVECTIVE OUTFLOW FROM WHATEVER
REMAINS OF THE MCS TONIGHT WILL PUSH THE STATIONARY FRONT FARTHER
SOUTH THAN WHERE IT IS NOW WITH A WEAK WAVE DEVELOPING ALONG THE
FRONT ACROSS SOUTH-CENTRAL KS BY DAYBREAK TUESDAY. WEST OF THE
WAVE...WINDS AT THE SURFACE WILL LIKELY BE MORE NORTHERLY ACROSS
MUCH OF THE DDC FORECAST AREA. TOMORROW`S FORECAST HIGH TEMPERATURE
HAS BEEN LOWERED TO MID-UPPER 90S FROM HAYS TO CIMARRON TO HUGOTON
AND POINTS WEST TO THE COLORADO BORDER. EVEN THE AREAS ACROSS SOUTH
CENTRAL KANSAS WILL BE SLIGHTLY NORTH OF THE FRONT MORE THAN LIKELY
AND HAVE LOWERED THE HIGHS IN MEDICINE LODGE AREA DOWN TO ABOUT
103-104F (WHICH MAY STILL BE A BIT TOO WARM IF THE FRONT ENDS UP
BEING JUST SOUTH OF THERE). AS FAR AS THUNDERSTORM POTENTIAL GOES
TOMORROW...IT WILL BE VERY SIMILAR TO TODAY...WITH THE GENERAL
THINKING BEING THAT ANYTHING THAT WOULD DEVELOP ALONG THE FRONT
WOULD BE VERY ISOLATED IN NATURE WITH THE MOST COHERENT CONVECTION
FORMING ONCE AGAIN OVER EASTERN COLORADO. WILL BE KEEPING POPS BELOW
15 EXCEPT NEAR THE COLORADO BORDER FOR LATE IN THE AFTERNOON TUESDAY
AS A RESULT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 336 PM CDT MON JUL 30 2012
AN UPPER LEVEL RIDGE WILL REMAIN ACROSS THE SOUTHERN PLAINS
WEDNESDAY AND THURSDAY, WITH WESTERN KANSAS LOCATED ALONG THE
SOUTHERN EDGE OF THE WESTERLIES NEAR A QUASI-STATIONARY SURFACE
FRONT. ORDINARILY THIS KIND OF PATTERN COULD RESULT IN ISOLATED
THUNDERSTORMS. BUT THIS YEAR THE LOW-LEVEL MOISTURE IS JUST VERY
LIMITED. NEVERTHELESS, ISOLATED THUNDERSTORMS CANNOT BE RULED OUT
EITHER DAY. TEMPERATURES WILL CONTINUE TO BE HOT, ESPECIALLY
SOUTH OF THE FRONT OVER SOUTH CENTRAL AND PARTS OF SOUTHWEST
KANSAS TO THE SOUTH OF THE FRONT.
ALTHOUGH THERE ARE SLIGHT DIFFERENCES IN MODEL TIMING, A STRONG
SHORTWAVE TROUGH IS ADVERTISED TO DIG INTO THE NORTHERN ROCKIES
FRIDAY AND THEN PASS ACROSS THE NORTHERN PLAINS BY SATURDAY.
AN OLD FRONT WILL STILL BE STALLED OUT ACROSS SOUTHWEST KANSAS, AND
A REINFORCING COLD FRONT WILL APPROACH KANSAS WITH THE NORTHERN
STREAM SYSTEM BY SATURDAY OR SATURDAY NIGHT. THERE WILL BE ADDITIONAL
SMALL CHANCES FOR THUNDERSTORMS EACH DAY, WITH THE EXACT LOCATION
DEPENDING ON WHERE THE FRONTAL BOUNDARIES ARE. IT WILL STILL BE HOT,
ESPECIALLY SOUTH OF THE FRONTS OVER SOUTH CENTRAL KANSAS, WITH HIGHS
ABOVE 105F FOR BOTH FRIDAY AND SATURDAY. SLIGHTLY COOLER TEMPERATURES
CAN BE EXPECTED IN WEST CENTRAL KANSAS. SLIGHTLY COOLER
TEMPERATURES ARE EXPECTED BY SUNDAY AND MONDAY ACROSS MOST OF
SOUTHWEST KANSAS AFTER THE AFOREMENTIONED SHORTWAVE TROUGH PUSHES
A COLD FRONT THROUGH KANSAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1239 AM CDT TUE JUL 31 2012
A DYING CONVECTIVE SYSTEM MOVING OUT OF NORTHWEST KANSAS WAS
MOVING EAST AND SHOULD STAY NORTH OF THE FORECAST AREA FOR THE
EARLY MORNING HOURS. HOWEVER THERE WERE ADDITIONAL SHOWERS AND
DEVELOPING THUNDERSTORMS IN SOUTHEAST COLORADO. THERE IS SOME HINT
THAT THIS ACTIVITY COULD SNEAK INTO OUR WESTERN COUNTIES. BUT IT
DOES NOT APPEAR LIKELY THAT CONVECTION WOULD REACH THE AVIATION
TERMINAL LOCATIONS. THE WIND SHIFT ASSOCIATED WITH THE NORTHWEST KANSAS
ACTIVITY WILL MOVE ACROSS THE AREA BUT ONLY WILL PRODUCE A FEW
WIND GUSTS TO 22 KT AT THE GREATEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 104 76 106 / 20 10 20 10
GCK 73 103 73 104 / 20 20 20 10
EHA 73 103 74 104 / 20 20 20 10
LBL 74 104 74 105 / 20 10 20 10
HYS 75 103 76 102 / 20 10 20 20
P28 78 108 78 109 / 10 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...HUTTON
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
240 AM EDT TUE JUL 31 2012
.UPDATE...
ISSUED AT 215 AM EDT TUE JUL 31 2012
UPDATED THE GRIDS TO REFLECT THE CONVECTION ONGOING OVER THE WESTERN
PARTS OF THE CUMBERLAND VALLEY. ALSO MATCHED THE OBS AND TRENDS TO
THE SKY...T AND TD GRIDS. UPDATES HAVE BEEN SENT.
UPDATE ISSUED AT 1015 PM EDT MON JUL 30 2012
CONVECTION ASSOCIATED WITH OUTFLOW BOUNDARIES OVER OUR EASTERN MOST
COUNTIES HAS DIED OUT WITH SUNSET. BUT STORMS CONTINUE TO DEVELOP
FURTHER TO THE EAST. SO COULD NOT RULE OUT A RENEGADE SHOWER OR
THUNDERSTORM SHOULD ANOTHER OUTFLOW SHOOT WESTWARD. FOR NOW WENT
OPTIMISTIC AND LEFT ANY MENTION OF POPS OUT OF THE FAR EAST AS
CONVECTION HAS A VERY SLOW BUT DEFINITE NORTHEAST TREND IN ITS
MOVEMENT.
SHORT WAVE ENERGY IS CURRENTLY DROPPING INTO THE LOWER AND MID OHIO
VALLEY REGION. THE RUC APPEARS TO HAVE A VERY GOOD HANDLE ON THE
SITUATION WITH CONVECTION FIRING IN SOUTHERN IL/IN ATTM. EXPECT
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OVER OUR
SOUTHWESTERN ZONES AFTER MIDNIGHT AND GENERALLY SOUTH OF A MOUNT
VERNON TO WHITESBURG LINE.
UPDATED THE FORECAST PACKAGE FOR SOME MINOR TWEAKS...MAINLY TO TEMPS
AND DEW POINTS AS TEMPERATURES HAVE DROPPED A LITTLE FASTER THAN
ANTICIPATED IN SEVERAL OF OUR VALLEY AREAS. ALSO FRESHENED UP WORDING
IN THE ZONE PACKAGE.
UPDATE ISSUED AT 721 PM EDT MON JUL 30 2012
OUTFLOW BOUNDARIES GENERATED FROM THUNDERSTORMS OVER WV HAVE BECOME
THE FOCUS FOR SOME ISOLD SHOWER ACTIVITY ACROSS PIKE AND LETCHER
COUNTIES. UPDATED THE FORECAST PACKAGE FOR THIS ACTIVITY THOUGH EXPECT
THINGS TO DIE DOWN QUICKLY AFTER SUNSET. REST OF THE FORECAST IS ON
TRACK. ONLY MINOR TWEAKS TO SKY AND POPS. OTHERWISE BROUGHT HOURLY
GRIDS IN LINE WITH MOST RECENT OBS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 330 PM EDT MON JUL 30 2012
AN UPPER LEVEL RIDGE REMAINS CENTERED NEAR THE TX PANHANDLE REGION
WITH A TROUGH BETWEEN THIS RIDGE AND ANOTHER OVER THE ATLANTIC. AS A
RESULT THE REGION CONTINUES IN NW FLOW ALOFT. AT THE SFC...HIGH
PRESSURE HAVE MOVED ON OFF TO OUR N AND E WITH A SFC LOW CENTERED
OVER SE MS AND A WARM FRONT EXTENDING SE FROM THE LOW INTO THE TN
VALLEY REGION. CONVECTION HAS BEEN PRESENT NEAR THIS BOUNDARY TODAY
AS WELL AS OVER SOME OF THE HIGHER TERRAIN OF THE CENTRAL AND
SOUTHERN APPALACHIANS. THERE MAY HAVE BEEN A FEW SPRINKLES IN FAR
SOUTHERN PIKE COUNTY NEAR THE VA LINE OVER THE PAST HOUR. OTHER THAN
A BIT DEEPER CU IN THAT VICINITY...JUST FAIR WEATHER CU HAS BEEN THE
DOMINANT FEATURE WITH TEMPS THUS FAR NEAR WHAT WOULD BE EXPECTED IN
LATE JULY.
A COUPLE OF UPPER LEVEL DISTURBANCES IN THE NW FLOW ALOFT MAY IMPACT
THE REGION DURING THE PERIOD. THE FIRST MOVING FROM THE MO VALLEY
TOWARD THE MID MS VALLEY REGION IS GENERALLY PROGGED TO TRACK TO THE
SW OF THE REGION AND INTERACT WITH THE BOUNDARY SW OF THE REGION. AT
THE SFC...THE RELATIVELY WEAK SFC LOW MAY TRACK TOWARD THE MIDDLE TN
REGION BY DAWN ON TUE...AND GENERALLY BECOMING DIFFUSE...WHILE A COLD
FRONT ASSOCIATED WITH A SHORTWAVE TO MOVE TROUGH THE GREAT LAKES
REGION LATE TONIGHT INTO TUE NIGHT APPROACHING THE REGION ON TUE.
THIS BOUNDARY SHOULD CROSS THE REGION ON TUE EVENING. SINCE THE FIRST
SHORTWAVE IS EXPECTED TO TRACK TO OUR SW AND THE SECOND TO OUR
NORTH...THE BEST DYNAMICS AND FORCING WILL NOT BE DIRECTLY OVER THE
REGION WITH EITHER ONE. WITH THIS IN MIND...POPS OF NO MORE THAN
CHANCE WERE USED. THE NE TWO THIRDS OF THE REGION SHOULD BE FAR
ENOUGH NORTHEAST TO REMAIN DRY TONIGHT WITH CONVECTION CHANCES BETTER
OVER THE CUMBERLAND VALLEY REGION. CONVECTION ON TUE SHOULD BE
DIURNALLY INFLUENCED...WITH THE THREAT LINGERING INTO THE EVENING AS
THE BOUNDARY SHOULD NOT CROSS THE AREA UNTIL THE OVERNIGHT. OVER THE
NE CWA TONIGHT...PATCHY VALLEY FOG IS AGAIN EXPECTED.
AS FOR TEMPS...THERE SHOULD BE A WINDOW ON TUE DURING THE MORNING
THROUGH EARLY AFTERNOON WHERE CLOUDS SHOULD THIN. MODEL GUIDANCE
POINTED TOWARD A BIT HIGHER MAX T ON TUE THAN THE PREVIOUS FORECAST...
NEAR 90 CWA-WIDE. MIN T THROUGH THE PERIOD WILL BE NEAR TO SLIGHTLY
ABOVE NORMAL...ESPECIALLY ON TUE NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 PM EDT MON JUL 30 2012
MODELS CONTINUE TO AGREE WITH OVERALL PATTERN EVOLUTION THROUGH THE
UPCOMING WEEK. TROF IN THE EASTERN UNITED STATES AND MEAN RIDGE IN
THE PLAINS WILL FLATTEN WITH FLOW BECOMING MORE ZONAL ACROSS THE
NORTHERN U.S. A SIGNIFICANT SHORT WAVE TROF IS PROGGED TO MOVE EAST
IN THE FAST FLOW ACROSS THE FAR NORTHERN PART OF THE COUNTRY DURING
THE LATTER PART OF THE WEEK AND DURING THE UPCOMING WEEKEND.
MODELS HAVE BEEN TRENDING DRIER FOR THE BEGINNING PART OF THE LONG
TERM FORECAST. WILL CARRY ONLY HAVE A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EXTREME EAST ON WEDNESDAY...BASICALLY PIKE
COUNTY ONLY...WITH A DRY FORECAST ELSEWHERE. WILL THEN GO WITH A DRY
FORECAST FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. AS DEEPER
MOISTURE RETURNS IN LOW LEVEL SOUTHWESTERLY FLOW AND WAA PATTERN
SETS UP IN ADVANCE OF LOW PRESSURE IN PLAINS WILL SEE A CHANCE OF
THUNDERSTORMS RETURN IN THE WEST PART OF FORECAST AREA ON FRIDAY
WITH A SLIGHT CHANCE IN THE EAST. AS LOW PRESSURE MOVES EAST ACROSS
SOUTHERN CANADA THIS WEEKEND A COLD FRONT WILL APPROACH THE AREA. IT
APPEARS THE FRONT WILL NOT MOVE SOUTH OF KY UNTIL MONDAY...THUS
KEEPING SHOWER AND THUNDERSTORM CHANCES IN THE FORECAST THROUGH THE
WEEKEND AND INTO EARLY NEXT WEEK. THE EXTENDED INITIALIZATION
PROCEDURE HANDLED THIS WELL WITH RAIN CHANCES CONTINUING INTO
MONDAY.
MAXIMUM TEMPERATURES SHOULD CONTINUE TO AVERAGE NEAR TO SLIGHTLY
ABOVE NORMAL THROUGH THE PERIOD...WITH WARMER THAN NORMAL MINIMUM
TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 240 AM EDT TUE JUL 31 2012
A SHORTWAVE INTERACTING WITH A WARM FRONT TO OUR SW IS PRODUCE SOME
SHOWER AND THUNDERSTORM ACTIVITY ACROSS SOUTHERN KY...GENERALLY IN
THE WESTERN PORTION OF THE CUMBERLAND VALLEY. VFR CIGS WILL BE A
POSSIBILITY ACROSS OUR SOUTH AND SOUTHWEST AVN SITES THROUGH THE
REMAINDER OF THE NIGHT AND INTO THE FIRST PART OF TUESDAY.
MEANWHILE...CLOUD COVER TO THE NE AND IN PARTICULAR JKL...AND
PORTIONS OF THE KY...LICKING RIVER BASINS WILL BE THINNER OR
NONEXISTENT LEADING TO RIVER VALLEY FOG THROUGH ROUGHLY 14Z POSSIBLY
AFFECTING THE K22...PBX...CPF...AND I35 SITES. WINDS THROUGH THE
PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JP
LONG TERM....SBH
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
128 AM EDT TUE JUL 31 2012
.SYNOPSIS...
ISSUED AT 345 PM EDT MON JUL 30 2012
A COLD FRONT WILL SWEEP SOUTHEAST THROUGH MICHIGAN TONIGHT...
BRINGING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. SOME OF
THE STORMS MAY BE STRONG TO SEVERE WEST OF HIGHWAY 131.
RAIN WILL END TUESDAY MORNING AS THE FRONT DEPARTS... WITH
DECREASING CLOUDS FOLLOWING. STRONG NORTH WINDS BEHIND THE FRONT
WILL CREATE HAZARDOUS SWIMMING AND BOATING CONDITIONS ON LAKE
MICHIGAN FOR TUESDAY AFTERNOON AND EVENING.
HIGH PRESSURE WILL PROVIDE DRY AND PLEASANT WEATHER ON WEDNESDAY...
THEN ANOTHER COLD FRONT WILL BRING A THREAT OF SHOWERS AND
THUNDERSTORMS ON THURSDAY.
&&
.UPDATE...
ISSUED AT 953 PM EDT MON JUL 30 2012
RADAR IS CURRENTLY LIT UP FROM THE BRIDGE SOUTHWEST TO NEAR
MANITOWOC. NEW ECHOS WERE FORMING SW OF MANITOWOC ACROSS CENTRAL
WISCONSIN AHEAD OF A COLD FRONT. LATEST HRRR BRINGS A BROKEN LINE
OF STORMS ACROSS THE CWA LATE TONIGHT. SHEAR VALUES ARE
CONSIDERABLY LESS ACROSS LOWER MI THAN ACROSS WISCONSIN. THINKING
THAT CHCS OF SVR STORMS ARE DIMINISHING BASED ON TIME OF DAY AND
MODEL PROGS OF SHEAR BUT A STRONG STORM OR TWO IS CERTAINLY
POSSIBLE. TWEAKED POPS TO REFLECT A BIT SLOWER TIMING THROUGH THE
CWA.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON JUL 30 2012
THE MID LEVEL SHORTWAVE TROUGH NOW OVER THE LAKE SUPERIOR REGION
WILL DIG SEWD TONIGHT. HEIGHT FALLS ASSOCIATED WITH THIS AMPLIFYING
WAVE AND LOW LEVEL CONVERGENCE ASSOCIATED WITH THE SFC COLD FRONT
WILL SET OFF A SCT-BKN LINE OF CONVECTION TO OUR NW OVER WI LATE
THIS AFTERNOON. THIS ACTIVITY IS EXPECTED TO EASILY SURVIVE THE TREK
ACROSS LAKE MI THIS EVENING AS AXIS OF INSTABILITY WITH MUCAPES
AROUND 2000 J/KG LEANS INTO WRN LWR MI AHEAD OF THE FRONT. LAKE MI
ACTUALLY MAY ALSO PROVIDE SOME BOOST GIVEN THE VERY WARM WATER TEMPS
AND ADDED SOURCE OF MOISTURE. HAVE RAISED POPS TO LIKELY OVER MUCH
OF THE CWFA TONIGHT.
SOME WIND DAMAGE MAY OCCUR WITH ANY ORGANIZED/BOWING LINES OF
CONVECTION TONIGHT. ALL THE JUICY DETAILS RELATED TO SEVERE WX
POTENTIAL CAN BE FOUND IN THE SPC DAY1 OTLK AS WELL AS ANY MESOSCALE
DISCUSSIONS FOR OUR AREA.
BELIEVE MOST OF THE CONVECTION WILL EXIT TO THE SOUTHEAST ON TUESDAY
MORNING. HOWEVER IT IS POSSIBLE SOME ENHANCEMENT AND/OR NEW
DEVELOPMENT WILL TAKE PLACE NEAR JXN IN THE LATE MORNING PRIOR TO
THE FRONT FULLY EXITING TO THE SE.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON JUL 30 2012
THE FOCUS OF THE LONG TERM WILL BE ON TWO SYSTEMS THAT WILL BE
MOVING THROUGH THE AREA. NO MAJOR CHANGES ARE NEEDED TO THE FCST AS
THE MODELS HAVE BEEN FAIRLY CONSISTENT WITH DECENT RUN TO RUN
CONTINUITY.
UPPER NW FLOW EXPECTED TO BE ALOFT MOST OF THIS WEEK WILL HOLD ON
FOR ONE MORE DAY ON THU/THU NIGHT AS A SOMEWHAT DISORGANIZED SHORT
WAVE MOVES THROUGH JUST NORTH OF THE AREA. THIS WAVE WILL HELP TO
PUSH A COLD FRONT SOUTH THROUGH THE AREA. MOST OF THE DYNAMICS WILL
REMAIN JUST NORTH OF THE AREA WITH THIS WAVE. THE FRONT WILL BE
WEAKENING AS IT PUSHES SOUTH THROUGH THE AREA. H850 TEMPS AROUND 20C
WILL HELP TEMPS WARM TO AROUND 90 THU AFTERNOON.
THE NW UPPER FLOW IS EXPECTED TO BEGIN FLATTENING OUT SOME THEN ON
FRI. THIS OCCURS AS THE STRONG WAVE THAT COMES FROM ITS CURRENT
POSITION ACROSS THE NRN PACIFIC TRANSLATES INTO THE AREA FOR NEXT
WEEKEND. MODELS ARE STARTING TO INDICATE THAT A WAVE MAY RIDE ALONG
THE STALLING OUT FRONT TO OUR SOUTH ON FRI. IF IT STALLS OUT A
LITTLE FURTHER NORTH...FRI MAY END UP A BIT MORE WET THAN CURRENTLY
INDICATED.
MODELS HAVE BEEN INDICATING THAT SAT AND SAT NIGHT COULD BE A
SOMEWHAT WET PERIOD AND POTENTIALLY ACTIVE AS THE STRONG WAVE/LOW
WILL BEGIN MOVING INTO THE AREA. STRONG FORCING AHEAD OF IT...ALONG
WITH A MOISTURE FEED FROM THE GULF WILL HELP TO BRING A GOOD CHC OF
PCPN TO THE AREA. THE NEW 12Z EURO JUST COMING IN IS NOW SLOWING THE
SYSTEM UP A BIT...SO WE WILL NEED TO WATCH THAT TREND.
WE SHOULD CLEAR OUT RATHER WELL AND COOL OFF A BIT BEHIND THE
SAT/SAT NIGHT SYSTEM AS A NICE CANADIAN AIR MASS ADVECTS IN. THIS
WILL DOMINATE THE WEATHER FOR THE FIRST PART OF NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 121 AM EDT TUE JUL 31 2012
A LINE OF THUNDERSTORMS EXTENDING FROM MKG TO GRR AT 06Z WILL
CONTINUE SOUTH AND EAST...AND SHOULD REACH JXN BY 09Z. SOME AREAS
OF MVFR CAN BE EXPECTED ALONG AND BEHIND THIS LINE OF STORMS BUT
VFR SHOULD RETURN BY 12Z AND CONTINUE THROUGH TUESDAY.
&&
.MARINE...
ISSUED AT 345 PM EDT MON JUL 30 2012
WILL ISSUE A SMALL CRAFT ADVISORY FOR TUESDAY AFTERNOON AND EVENING.
INCREASING NORTH FLOW AND COLD ADVECTION OVER VERY WARM LAKE WATERS
IS BOUND TO KICK UP THE LAKE TO ADVISORY LEVELS.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT MON JUL 30 2012
RAIN AMOUNTS WITH THE FRONT TONIGHT SHOULD BE GENERALLY ONE QUARTER
TO ONE HALF INCH. HOWEVER SOME LOCALLY HIGHER AMOUNTS NEAR ONE INCH
ARE CERTAINLY POSSIBLE. WHILE LOCALIZED NUISANCE FLOODING IS
POSSIBLE IN URBAN AREAS IF/WHERE HEAVY DOWNPOURS OCCUR... WE REALLY
NEED THIS RAIN FOR DROUGHT RELIEF.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT FROM NOON EDT TODAY THROUGH LATE TONIGHT
FOR MIZ037-043-050-056-064-071.
LM...SMALL CRAFT ADVISORY FROM NOON TODAY TO 5 AM EDT WEDNESDAY FOR
LMZ844>849.
&&
$$
UPDATE...93
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...NJJ
AVIATION...OSTUNO
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1244 AM CDT TUE JUL 31 2012
.UPDATE...
ISSUED AT 1236 AM CDT TUE JUL 31 2012
CLEARING SKIES...LIGHT WIND...AND DEWPOINTS IN THE LOWER 70S HAS
LED TO SOME PATCHY FOG DEVELOPMENT. MANY STATIONS ACROSS THE AREA
ALREADY REPORTING 4-6SM. HAVE UPDATED THE SHORT TERM FORECAST TO
INCLUDE PATCHY FOG THROUGH DAYBREAK.
CVKING
&&
.SHORT TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TONIGHT)
EXTENSIVE AREA OF MID AND HIGH CLOUDS HAVE HELPED HOLD TEMPERATURES
BACK OVER MOST OF THE REGION TODAY. SURFACE REPORTS FROM THE LARGE
AREA OF RETURNS ON RADAR ARE MAINLY SPRINKLES. THIS IS BEING
GENERATED BY A VORT MAX THAT WILL MOVE SOUTH INTO THE SOUTHERN CWA
BY 00Z. THERE IS LITTLE LOW LEVEL FORCING ASSOCIATED WITH IT
ACCORDING TO THE RAP UNTIL AFTER 00Z...AND EVEN THEN IT IS QUITE
WEAK. THINK GOING SLIGHT CHANCES FOR SHOWERS/THUNDERSTORMS STILL
LOOKS OKAY GIVEN SLIGHTLY BETTER LOW LEVEL FORCING AND MORE
INSTABILITY. OTHERWISE CHANCES SHOULD DECREASE WITH TIME AS THE
LOW MOVES FARTHER SOUTH.
BRITT
&&
.LONG TERM...
ISSUED AT 344 PM CDT MON JUL 30 2012
(TUESDAY THROUGH NEXT MONDAY)
MAIN CONCERN ONCE AGAIN IS HEAT. HAVE ISSUED A HEAT ADVISORY JUST
FOR THE ST. LOUIS METRO AREA ON TUESDAY AFTERNOON AS IT CURRENTLY
LOOKS LIKE HEAT INDEX READINGS WILL CLIMB TO AROUND 105 DURING THE
AFTERNOON.
GFS/NAM ARE IN RELATIVELY GOOD AGREEMENT THAT A WEAK COLD FRONT WILL
BE MOVING SOUTH OUT OF THE UPPER MIDWEST INTO NORTHERN MISSOURI AND
CENTRAL ILLINOIS AROUND MIDDAY TOMORROW. DO NOT EXPECT MUCH CLOUDS
AND ANY RAIN CHANCES WITH THIS FRONT AS WE WILL LIE UNDER SUBSIDENCE
BETWEEN A SHORTWAVE TROUGH MOVING THROUGH THE GREAT LAKES AND A
VORT MAX MOVING ACROSS SOUTHWEST MISSOURI. NAM FORECAST SOUNDINGS
SHOWING DEEP MIXING TO 700MB AHEAD OF THE FRONT WHICH SUPPORTS
GOING HIGHS WHICH ARE CLOSE TO THE NAM MOS TEMPERATURES WHICH HAVE
VERIFIED BETTER THIS SUMMER. DEWPOINTS SHOULD FALL INTO THE UPPER
50S TO LOWER 60S WITH THE MIXING...WHICH COMBINED WITH HIGHS
RISING TO AROUND 104 RESULT IN HEAT INDEX HIGHS BRIEFLY REACHING
105 TOMORROW AFTERNOON. TEMPERATURES ON WEDNESDAY LOOK TO BE NOT
AS WARM BEHIND THE FRONT...SO HEAT INDEX READINGS ARE EXPECTED TO
STAY BELOW 100 DEGREES. ANOTHER FRONT MOVES INTO NORTHERN MISSOURI
LATE THURSDAY/THURSDAY NIGHT...WITH THE GFS BRINGING IT THROUGH
THE AREA AND THE ECMWF KEEPING IT STALLED TO THE NORTH AS THE
UPPER FLOW BECOMES ZONAL. HAVE GONE WITH JUST A SLIGHT CHANCE FOR
SHOWERS/STORMS ON THURSDAY AND TEMPERATURES IN THE UPPER 90S WHICH
SHOULD RESULT IN HEAT INDEX READINGS BETWEEN 98-103.
GENERALLY STAYED WITH THE ECMWF OVER THE WEEKEND. SHOULD BE SOME
INCREASE IN LOW LEVEL FORCING AHEAD OF A COLD FRONT THAT WILL MOVE
ACROSS THE AREA ON SUNDAY...SO HAVE KEPT A CHANCE OF SHOWERS AND
THUNDERSTORMS GOING AHEAD OF IT. WITH 850MB TEMPS STAYING ABOVE
20C...HIGH TEMPERATURES SHOULD REMAIN ABOVE 90 THROUGH THE PERIOD.
BRITT
&&
.AVIATION...
ISSUED AT 1021 PM CDT MON JUL 30 2012
MID LEVEL CLOUDINESS OVER SRN AND W CNTRL MO WILL CONTINUE TO DROP
SWD LATE TGT...LIKELY ONLY IMPACTING COU TIL 06-07Z TUE...AND
REMAINING S-SW OF THE OTHER TAF SITES. SFC WINDS WILL BE LIGHT
TGT AS WEAK SFC RIDGE CENTERED OVER NERN MO SHIFTS SEWD. DUE TO
THE CLEARING SKY THIS EVNG ALONG WITH HIGH SFC DEWPOINTS AND LIGHT
WINDS THERE SHOULD BE SOME LIGHT PATCHY FOG LATE TGT AND EARLY
TUE MRNG WITH VSBYS DROPPING DOWN TO AROUND 3-5 MILES. A WEAK
COLD FRONT NOW OVER THE GREAT LAKES AND NRN PLAINS REGIONS WILL
DROP SEWD THROUGH OUR AREA ON TUE. ONLY ISOLATED SHOWERS/STORMS
EXPECTED ALONG THIS FRONT IN OUR AREA SO WILL LEAVE THE TAFS DRY
FOR NOW...PLUS LITTLE CLOUD COVER EXPECTED ON TUE. NWLY SFC WINDS
WILL INCREASE TUE AFTN AFTER FROPA...THEN BECOME N-NELY TUE EVNG
AS A SFC RIDGE BUILDS SEWD INTO THE GREAT LAKES REGION BEHIND THE
COLD FRONT.
SPECIFICS FOR KSTL...THE MID LEVEL CLOUD DECK HAS RECENTLY SHIFTED
S OF STL THIS EVNG AND SHOULD REMAIN S-SW THE REMAINDER OF THE
NIGHT WITH LITTLE CLOUD COVER EXPECTED FOR THE REST OF THE TAF
PERIOD. LIGHT SFC WINDS LATE TGT AND TUE MRNG COULD LEAD TO LIGHT
FOG OR HAZE LATE TGT AND EARLY TUE MRNG OF AROUND 5SM. THE SFC
WIND WILL INCREASE TO AROUND 10 KTS TUE AFTN FROM A NWLY DIRECTION
AFTER PASSAGE OF A WEAK COLD FRONT. COULD BE ISOLATED SHOWERS/STORMS
ALONG THIS FRONT IN THE ST LOUIS METRO AREA...BUT WILL LEAVE STL
TAF DRY FOR NOW AS CONVERGENCE ALONG FRONT SHOULD BE WEAK AND ANY
SIGNIFICANT MOISTURE SHOULD BE THIN OR SHALLOW. THE SFC WIND
SHOULD WEAKEN TUE NGT AND BECOME MORE NELY.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
JEFFERSON MO-ST. CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO.
IL...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
MADISON IL-MONROE IL-ST. CLAIR IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1234 AM CDT TUE JUL 31 2012
.AVIATION...
THE THUNDERSTORM SYSTEM THAT DEVELOPED IN EASTERN COLORADO
REMAINED OVER EXTREME SOUTHWEST NEBRASKA AND NORTHWEST KANSAS. SHORT
RANGE PROJECTIONS INDICATE THAT SHOWERS AND THUNDERSTORMS MAY
DEVELOP OVER NORTHWEST NEBRASKA NORTH AND WEST OF A VTN-MHN-AIA
LINE. THE PROBABILITY OF ANY AT VTN OR MHN IS VERY LOW. IN THE LAST
PART OF THE FORECAST PERIOD...18-21Z...THUNDERSTORMS MAY DEVELOP
SOUTH AND WEST OF AIA-TIF-LBF. AGAIN...THE PROBABILITY IS TOO LOW TO
WARRANT INCLUSION IN THE TERMINAL FORECASTS FOR VTN AND LBF.
&&
.PREV DISCUSSION... /ISSUED 643 PM CDT MON JUL 30 2012/
AVIATION...
A FEW THUNDERSTORMS CAN BE EXPECTED THIS EVENING OVER THE
NEBRASKA PANHANDLE AND NORTHWEST NEBRASKA...NORTH AND WEST OF AN
ONL-IML LINE WITH THE HIGHEST PROBABILITY NORTH AND WEST OF AN
ANW-OGA LINE. THE THUNDERSTORM PROBABILITY IS LESS THAN 30 PERCENT
OVER EITHER AREA AND...FOR THE TIME BEING...WILL NOT BE INCLUDED IN
THE TERMINAL FORECASTS FOR VTN AND LBF. OTHERWISE...SOME HIGH-BASED
CUMULUS CLOUDS ARE EXPECTED ALONG WITH CIRROSTRATUS AND NO OTHER
FLIGHT RESTRICTIONS ARE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 333 PM CDT MON JUL 30 2012/
DISCUSSION...
MOISTURE AS INDICATED ON SFC OBS SHOWING DEW PTS IN THE 60S AND
SATELLITE TPW PRECIPITABLE WATER ESTIMATES NEAR 1.3 INCHES OR HIGHER
ACROSS SWRN NEB WOULD SUGGEST A REASONABLE CHANCE OF TSTMS GIVEN
THE WEAK DISTURBANCE MOVING THROUGH NRN COLO THIS AFTN. HOWEVER
THE HRRR AND THE RAP MODELS ARE VERY QUIET GENERATING LIMITED CONVECTIVE
ACTIVITY ACROSS THE HIGH PLAINS. THIS COULD BE THE RESULT OF WEAK
UPSLOPE ADVECTION...A MID LEVEL SUBSIDENCE/CAP AND WEAK STEERING
CURRENTS. MEANWHILE THE KLNX VWP INDICATES A VERY DEEP BUT WEAK
EAST WINDS EXTENDING ALL THE WAY TO 12 KFT ASL.
THE FCST THIS EVENING CALLS FOR ISOLATED STORMS GENERALLY ALONG
AND WEST OF HIGHWAY 61. WE WILL CONTINUE TO CLOSELY MONITOR THE
CONVECTION DEVELOPING IN COLO AND OBVIOUS DEEP MOISTURE PLUME
ACROSS SWRN NEB. UPSLOPE FLOW MAY INCREASE LATE THIS AFTN AND
EARLY THIS EVENING ENHANCING CONVERGENCE. THE MODERATE CU FORMING
SOUTH OF THE WEATHER OFFICE AND CIGS NEAR 5 KFT AT HOLYOKE SUGGEST
ATLEAST SOME POTENTIAL FOR ORGANIZED STORM DEVELOPMENT IF THE
DISTURBANCE ACROSS COLO CAN REACH SWRN NEB BY EARLY EVENING.
ON TUESDAY...LOW PRESSURE WILL BEGIN TRACKING THROUGH THE NRN
PLAINS WHILE HIGH PRESSURE CONTINUES ACROSS ERN NEB. THIS SHOULD
PRODUCE COOLER TEMPS SOUTH AND EAST IN THE SOUTH-SOUTHEAST WIND
AREA AND VERY WARM TEMPS ACROSS THE NW ZONES WHERE DOWN SLOPING
SOUTHWEST WINDS MAY DEVELOP. THE MOISTURE PLUME BECOMES DIFFUSE
AND LESS FOCUSED AS IT IS DRAWN NORTH IN ALL MODELS EXCEPT THE GFS
WHICH EXPLODES WEDNESDAY EVENING OVER SRN SD/NCNTL NEB AS A COLD
FRONT APPROACHES THE FCST AREA. THE FATE OF THIS MOISTURE PLUME
THE POTENTIAL FOR DESPERATELY NEEDED RAINFALL MIGHT BEST BE
HANDLED INSIDE 12 HRS. THE OTHER MODELS ARE NOT GENERATING MUCH
QPF...POSSIBLY THE RESULT OF WARM MIDLEVEL LAPSE RATES.
A WEAK AREA OF COOLER HIGH PRESSURE WILL BUILD BEHIND THE FRONT
THURSDAY AND TEMPS SHOULD SETTLE BACK IN TO THE 90S AFTER HIGHS
AROUND 100 WEDNESDAY. ALL MODELS ARE IN GOOD AGREEMENT THAT A DEEP
DISTURBANCE WILL MOVE THROUGH NRN HIGH PLAINS FRIDAY. THIS SYSTEM
SHOULD PRODUCE STRONG SOUTHWEST WINDS WITH TEMPERATURES RISING TO
OR ABOVE 100F IN MANY AREAS. A POWERFUL COLD FRONT WILL SWEEP
THROUGH FRIDAY NIGHT AND COOL TEMPS BACK INTO THE 80S FOR SATURDAY.
THE ECM HOLDS COOL HIGH PRESSURE INPLACE SUNDAY WHILE THE GFS IS
OFF TO THE RACES DEEPENING LOW PRESSURE ACROSS THE NRN HIGH PLAINS.
THE ECM IS PREFERRED FOR HIGHS IN THE LOWER 90S. BOTH MODELS ARE
SHOWING A STRONG THERMAL RIDGE ACROSS THE HIGH PLAINS MONDAY. THIS
SHOULD EASILY PRODUCE HIGHS IN THE UPPER 90S.
THE UPPER LEVEL RIDGE AND ASSOCIATED SFC HEAT LOW SHOULD REMAIN
ACROSS THE SRN HIGH PLAINS AND MID SOUTH DURING THE NEXT 7 DAYS.
THE ECM IS TRYING TO AMPLIFY THE RIDGE INTO THE CENTRAL PLAINS BY
NEXT MONDAY. RAIN CHANCES ARE GENERALLY CONFINED TO THE NORTH AND
EAST LATE FRIDAY WITH THE APPROACHING COLD FRONT. A WEAK
DISTURBANCE CROSSING ERN WY AND THE BLACK HILLS THURSDAY MAY BE
THE CATALYST FOR ISOLATED STORMS LATE IN THE DAY OR AT NIGHT
ACROSS MUCH OF THE FCST AREA. THE REST OF THE FCST...SATURDAY THROUGH
MONDAY...IS DRY.
BE AWARE THAT THE ONLY REAL HOPE FOR RAINFALL DURING THE NEXT 4
DAYS LIES IN THE FATE OF THE MOISTURE PLUME ACROSS SRN NEB THIS
AFTERNOON. THERE REMAINS A VAST AREA OF VERY DRY AIR AT THE
SURFACE AND LOWER LEVELS OF THE ATM. IN FACT THE WATER VAPOR
PAIRED WITH THE TPW PRODUCT SHOW A TREMENDOUS SURGE OF DRY AIR
FEEDING IN OFF THE PACIFIC THROUGH NEVADA...ID AND MT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...SPRINGER
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1220 AM CDT TUE JUL 31 2012
.DISCUSSION.../ISSUED AT 951 PM CDT/
FORECAST IN PRETTY GOOD SHAPE THIS EVENING...ALTHOUGH SEEING TEMPS
DROP OFF MORE QUICKLY THAN EXPECTED IN A FEW PLACES. HAVE TWEAKED
HOURLY GRIDS ACCORDINGLY...WITH MINOR UPDATES TO LOW TEMPERATURES.
WITH THE COOLING...LIGHT WINDS...AND RECENT RAINS ACROSS THE EAST...
HAVE ADDED SOME PATCHY FOG INTO SOME OF OUR MN/IA COUNTIES AGAIN FOR
LATE TONIGHT..AND UPDATED GRIDS/ZFP/PFM HAVE BEEN SENT FOR THAT.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR CONDITIONS WILL PREVAIL THROUGH 06Z WEDNESDAY...WITH LIGHT SOUTH
SOUTHEAST WINDS EXPECTED DURING THE DAY TUESDAY.
&&
.PREV DISCUSSION.../ISSUED AT 315 PM CDT/
SURFACE FRONT MOVING THROUGH NORTHWEST IOWA AS OF 19Z WITH MAIN PUSH
OF COOLER AIR APPROACHING I90. THE COOLER AIR SHOULD SPREAD SOUTH
ACROSS THE CWA OVERNIGHT WITH LOWS EXPECTED TO BE IN THE LOWER TO
MID 60S. WILL KEEP A VERY SMALL CHANCE OF STORMS ACROSS FAR
SOUTHEAST CWA THROUGH EARLY EVENING AS LATEST SATELLITE SHOWING SOME
ACCAS TRYING TO FORM FROM SOUTH OF SPW TO NEAR SUX AND WITH
TEMPERATURES GETTING CLOSE TO BREAKING CAP THERE CAN NOT RULE A FEW
STORMS YET LATE THIS AFTERNOON AND EARLY EVENING AS WEAK WAVE DROPS
SOUTHEAST INTO SOUTHWEST MINNESOTA WHICH ALSO SHOWS UP WELL ON
SATELLITE. LATEST HRRR MODELS CONTINUES TO CONFIRM THIS POSSIBILITY.
OTHERWISE...EXPECT MOSTLY CLEAR SKIES OVERNIGHT.
SOMEWHAT ACTIVE WEATHER PATTERN EXPECTED INTO THE END OF THE WEEK AS
THE PATTERN TRANSITIONS FROM A SHARP HIGH PLAINS RIDGE INTO A MORE
ZONAL PATTERN BY LATE WEEK. IN THE SHORT RANGE...EXPECT A FEW FAIRLY
WEAK WAVES TO DROP SOUTHEAST FROM SOUTHERN CANADA INTO THE NORTHERN
PLAINS. AS IS TYPICAL FOR THESE WEAK WAVE SCENARIOS...MODELS NOT
SHOWING MUCH CONSISTENCY IN THE TIMING AND TRACK OF THESE WAVES
DURING THE MID WEEK. GIVEN THE MEAGER MOISTURE...CONDITIONAL
INSTABILITY AND MODEL UNCERTAINTY...IT IS HARD TO PINPOINT ANY ONE
TIME FRAME AS THE "BETTER" POTENTIAL FOR SHOWER OR THUNDERSTORM
ACTIVITY. WITH THIS IN MIND...WILL KEEP ISOLATED POPS IN THE
FORECAST JUST ABOUT EVERY PERIOD FROM TUESDAY NIGHT THROUGH
THURSDAY. ANY ACTIVITY THAT MANAGES TO DEVELOP SHOULD BE HIGH BASED
AND NOT A HEAVY RAIN PRODUCER. HIGHS WILL BE QUITE WARM ON WEDNESDAY
WITH THE 90S TO NEAR 100 EXPECTED...AND WILL BE AROUND 5 DEGREES
COOLER ON THURSDAY.
LATE IN THE WEEK MARKS THE APPROACH OF A CUT OFF UPPER LOW WHICH
DIGS ALONG THE CANADIAN BORDER WITH MONTANA ON FRIDAY THEN HEADS
INTO THE NORTHERN GREAT LAKES BY SATURDAY NIGHT. THERE ARE SOME
FAIRLY SIGNIFICANT MODEL DIFFERENCES WITH THIS SYSTEM. THE LATEST
ECMWF...ONCE THE FASTEST SOLUTION...IS NOW 6 TO 12 HOURS SLOWER AND
IS THE WEAKEST SOLUTION. THE GEM TAKES THE LOW FARTHER SOUTH INTO
THE NORTHERN PLAINS WHILE THE GFS IS SLIGHTLY STRONGER AND THE MOST
NORTHERN TRACK. ALL OF THESE SOLUTIONS DO SEND A FAIRLY STRONG FRONT
THROUGH THE FORECAST AREA FRIDAY NIGHT OR SATURDAY WHICH APPEARS TO
BE THE BEST POTENTIAL FOR SOME WET WEATHER IN THE NEXT SEVEN DAYS.
WILL CONTINUE CARRYING LIKELY POPS FRIDAY NIGHT IN OUR NORTHERN HALF
WITH CHANCES ELSEWHERE. WITH THE INCREASED CLOUD COVERAGE AND
RAINFALL CHANCES FRIDAY AND SATURDAY...AS WELL AS COOLER NORTHWEST
FLOW WORKING INTO THE AREA SATURDAY AND SUNDAY...TEMPERATURES WILL
BE MUCH CLOSER TO NORMALS INTO THE WEEKEND.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
344 AM CDT TUE JUL 31 2012
.SHORT TERM...TODAY THROUGH THURSDAY
343 AM CDT TUE JUL 31 2012
AT 3 AM...A COLD FRONT EXTENDED FROM ANN ARBOR MICHIGAN TO
FREEPORT ILLINOIS TO SLATER IOWA. AN EXTENSIVE AREA OF SHOWERS AND
THUNDERSTORMS HAVE DEVELOPED FROM NORTHERN ILLINOIS EAST NORTHEAST
INTO SOUTHERN LOWER MICHIGAN. THESE THUNDERSTORMS ARE EXCEEDING
50K FEET AND AS RESULT...WE CAN STILL SEE THE IN-CLOUD LIGHTNING
FROM STORMS WHICH ARE AT LEAST 130 MILES FROM OUR OFFICE.
IN THE WAKE OF THIS FRONT...A CANADIAN HIGH PRESSURE SYSTEM IS
BUILDING INTO THE REGION. THIS HIGH WILL PROVIDE CLEAR SKIES
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY TODAY AND MUCH OF THE
TONIGHT. BUFKIT SOUNDINGS SUGGEST THAT THE AREA WILL MIX UP TO
825 MB THIS AFTERNOON. THIS WILL ALLOW TEMPERATURES TO CLIMB INTO
THE 78 TO 83 DEGREE RANGE IN MOST AREAS. THE DRY SAND IN THE RIVER
VALLEYS WILL ALLOW THESE AREAS TO WARM UP EVEN MORE. TEMPERATURES
IN THE MISSISSIPPI AND WISCONSIN RIVER VALLEYS WILL LIKELY CLIMB
INTO THE UPPER 80S. WITH VERY DRY AIR ALOFT...DEW POINTS WILL
LIKELY INTO THE 50S AND LOWER 60S THIS AFTERNOON. THIS IS SLIGHTLY
LOWER THAN THE MOS GUIDANCE.
FOR TONIGHT...THE MAIN QUESTION IS WHETHER VALLEY FOG WILL DEVELOP.
WITH TEMPERATURES FALLING INTO THE 50S AND LOWER 60S AND RIVER
TEMPERATURES AROUND 80...IT WOULD NORMALLY CONDUCIVE FOR THE
DEVELOPMENT OF VALLEY FOG...BUT IN THIS SITUATION THERE IS CONCERN
THAT THE DEW POINTS WILL NOT RECOVER FAST ENOUGH FOR THIS TO OCCUR.
THE ONE EXCEPTION LOOKS TO BE IN THE WISCONSIN RIVER VALLEY WHERE
THE STEEPER VALLEY MAY ENHANCE THE COLD AIR DRAINAGE LEADING TO
THE GREATER POTENTIAL OF FOG DEVELOPMENT AFTER MIDNIGHT.
ON WEDNESDAY AFTERNOON AND NIGHT...ANOTHER CANADIAN COLD FRONT
WILL MOVE SOUTHEAST INTO THE REGION. SOUNDINGS SHOW THAT THERE IS
STRONG CAP FOR MUCH OF THE DAY AHEAD OF THIS FRONT AND THIS WILL
ALLOW TEMPERATURES TO WARM INTO THE LOWER AND MID 90S. AS THE
FRONT APPROACHES...THE CAP WILL SLOWLY ERODE. THERE IS PLENTY OF
DRY AIR BELOW 10K FEET...SO ANY SHOWERS AND THUNDERSTORMS THAT DO
DEVELOP WILL BE HIGH BASED. THE DRY AIR BELOW THE CLOUD BASE WILL
ENHANCE THE POTENTIAL OF DAMAGING WINDS WITH ANY OF THE STORMS
THAT DO HAPPEN DEVELOP. HOWEVER THE CONVERGENCE IS NOT THAT GREAT
ALONG THIS FRONT...MOISTURE TRANSPORT IS WEAK...AND THE
INSTABILITY IS NOT THAT IMPRESSIVE...SO THERE IS PLENTY OF
QUESTION WHETHER ANY THUNDERSTORMS WILL EVEN DEVELOP.
ON THURSDAY...THE MODELS CONTINUE TO SUGGEST THAT A WEAK FRONT
WILL BE DRAPED ACROSS THE AREA. ML CAPES CLIMB TO AROUND 1000 J/KG.
HOWEVER THE ML CINS ARE STILL AROUND 100 J/KG AND THE SURFACE AND
ELEVATED CONVERGENCE ALONG THIS FRONT IS VERY WEAK. AS A RESULT...
NOT TOO EXCITED ABOUT THE THE SHOWER AND THUNDERSTORM
PROBABILITIES...SO LEFT THEM AROUND 20 PERCENT.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
343 AM CDT TUE JUL 31 2012
ON FRIDAY AND FRIDAY NIGHT...SOUTHERLY WINDS AHEAD OF A STRONG
SHORT WAVE TROUGH WILL BRING VERY WARM AIR INTO THE REGION. THE
ALL BLEND TEMPERATURES LOOK TOO LOW CONSIDERING THE WARM AIR
MOVING IN ALOFT. AS A RESULT...TRENDED THEM UPWARD BY MIXING IT
WITH THE ECMWF WHICH IS MUCH WARMER AND PROBABLY MORE REALISTIC.
ON SATURDAY AND SATURDAY NIGHT...A DYNAMIC SYSTEM WILL BE MOVING
THROUGH THE REGION. BY FAR...THE GEM IS MORE DYNAMIC /NEGATIVELY
TILTED/ THAN EITHER THE ECMWF AND GFS. THIS SYSTEM HAS THE
POTENTIAL OF PRODUCING SEVERE WEATHER...BUT THE TIMING OF THE WAVE
DOES NOT LOOK THAT GOOD FOR OUR AREA.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1149 PM CDT MON JUL 30 2012
HIGH PRESSURE WILL DOMINATE THE PATTERN THROUGH THE TAF PERIOD.
CLEAR SKIES ARE EXPECTED WITH WINDS LESS THAN 10 KNOTS. BOTH THE
31.02Z RAP AND 31.00Z NAM SHOWS WINDS ABOVE 10 KNOTS JUST ABOVE
THE SURFACE OVERNIGHT TONIGHT AND THIS SHOULD PRECLUDE ANY FOG FORMATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
251 AM CDT TUE JUL 31 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CDT MON JUL 30 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY
247 PM CDT MON JUL 30 2012
MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES THIS
EVENING. FOCUS THEN TURNS TO VALLEY FOG POTENTIAL TONIGHT AND AGAIN
WEDNESDAY NIGHT AND SHOWER/THUNDERSTORM CHANCES WEDNESDAY NIGHT
INTO THURSDAY.
LATEST SURFACE OBSERVATIONS SHOWED A COLD FRONT EXTENDING FROM
IRONWOOD MICHIGAN...TO NEAR RICE LAKE WISCONSIN...TO NEAR ST.
JAMES MINNESOTA...DRIFTING SOUTHEAST. MESOSCALE FORECAST MODELS
CONTINUE TO SUGGEST THAT SHOWERS AND THUNDERSTORMS WILL FIRE ALONG
THIS FRONT IN THE 4 TO 6 PM TIME FRAME. THIS WOULD PUT THE FRONT
OVER CENTRAL WISCONSIN...EXTENDING SOUTHWEST INTO NORTHEAST IOWA.
LATEST VISIBLE SATELLITE IMAGERY SHOWED A WELL DEFINED CUMULUS
FIELD AHEAD OF THE FRONT. NO PRECIPITATION RETURNS ON RADAR YET
ALONG THIS FIELD. THINKING THE FRONT WILL FINALLY GENERATE
CONVECTION AS IT MOVES INTO CENTRAL AND FAR SOUTHWEST
WISCONSIN...EXTENDING INTO NORTHEAST IOWA. DRY LOW LEVELS WILL LEAD
TO THE POTENTIAL FOR DAMAGING WINDS WITH ANY STORMS THAT DEVELOP.
LATEST RAP ANALYSIS INDICATES NEARLY 1400-1600 DOWNDRAFT CAPE
AHEAD OF THE COLD FRONT. 0-6 KM SHEAR IS RATHER WEAK...GENERALLY
LESS THAN 30 KTS...SO STORMS MAY STRUGGLE TO BECOME ORGANIZED ONCE
THEY DEVELOP. SURFACE BASED CAPE VALUES OF NEARLY 4000 J/KG WILL
LEAD TO STRONG UPDRAFTS...WITH MARGINALLY SEVERE HAIL POSSIBLE.
THE COLD FRONT WILL PUSH EAST OF THE FORECAST AREA LATE THIS EVENING
WITH HIGH PRESSURE BUILDING INTO THE REGION. FORECAST SOUNDINGS ARE
SHOWING THE POTENTIAL FOR SOME VALLEY FOG DEVELOPMENT ALONG THE
MISSISSIPPI RIVER. THE AIR MASS LOOKS A BIT ON THE DRY SIDE FOR THIS
TO OCCUR. TEMPERATURE AND DEW POINT SPREADS AT KLSE APPROACH TWO
DEGREES BUT THIS OCCURS LATE IN THE NIGHT/EARLY MORNING...AROUND
11Z. WINDS ARE MORE FAVORABLE...WITH LIGHT WIND FROM THE SURFACE
THROUGH 2 KFT. THINKING A BRIEF PERIOD OF PATCHY VALLEY FOG IS
POSSIBLE TONIGHT...ESPECIALLY IF ANY PRECIPITATION FALLS THIS
EVENING. ANOTHER FACTOR POSSIBLY WORKING AGAINST VALLEY FOG IS A LOW
CLOUD DECK APPROACHING THE FORECAST AREA BEHIND THE COLD FRONT.
THESE CLOUDS LOOK TO PASS JUST EAST OF THE MISSISSIPPI SO WILL HAVE
TO KEEP A CLOSE WATCH ON THESE. OTHERWISE...PLAN ON SKIES RANGING
FROM MOSTLY CLEAR TO PARTLY CLOUD DURING THE OVERNIGHT HORUS. LOOK
FOR LOW TEMPERATURES WILL RANG FROM LOWER 60S ACROSS NORTHERN
WISCONSIN TO THE UPPER 60 OVER NORTHEAST IOWA.
SLIGHTLY COOLER AIR WILL MOVE INTO THE REGION BEHIND THE FRONT LATE
TONIGHT INTO TUESDAY. 850 MB TEMPERATURES WILL FALL FROM 22C MONDAY
AFTERNOON INTO THE 14 TO 16 C RANGE BY EARLY TUESDAY MORNING. HIGH
PRESSURE WILL BE IN CONTROL THROUGH THE DAY ON TUESDAY PROVIDING
MOSTLY SUNNY SKIES. PLAN ON HIGHS RANGING FROM THE LOWER 80S ACROSS
NORTHERN WISCONSIN TO THE UPPER 80S OVER NORTHEAST IOWA.
HIGH PRESSURE IS EXPECTED TO SLIDE EAST OF THE FORECAST AREA TUESDAY
NIGHT INTO WEDNESDAY MORNING AS ANOTHER COLD FRONT APPROACHES FROM
WESTERN MINNESOTA AND EAST SOUTH DAKOTA. FORECAST SOUNDINGS AGAIN
SHOW THE POTENTIAL FOR SOME VALLEY FOG. HIGH PRESSURE WILL BE
SETTLED OVER THE AREA DURING THE OVERNIGHT HOURS PROVIDING LIGHT AND
VARIABLE WINDS. TEMPERATURE/DEW POINT SPREADS APPROACH TWO DEGREES
BY 09Z. WILL HAVE TO KEEP A CLOSE WATCH ON SOME HIGH CLOUDS TRYING
TO STREAM IN FROM THE WEST. CURRENT THINKING IS THAT AREAS OF FOG
WILL DEVELOP ALONG THE MISSISSIPPI AND WISCONSIN RIVER VALLEY.
FORECAST MODELS ARE SHOWING VERY DRY AIR ADVECTING INTO THE AREA
AHEAD OF THE APPROACHING FRONT. WINDS WILL SHIFT TO THE SOUTHWEST
BY WEDNESDAY AFTERNOON AS THE FRONT APPROACHES. DEW POINTS PLUMMET
AS THIS OCCURS...ESPECIALLY ACROSS NORTHEAST IOWA...PORTIONS OF
SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN. COULD SEE DEW POINTS
FALL INTO THE MID 40S BY THE MID AFTERNOON HOURS. THE COLD FRONT
IS EXPECTED TO MOVE INTO THE AREA LATE WEDNESDAY AFTERNOON INTO
WEDNESDAY NIGHT AS A SHORTWAVE TROUGH MOVES OVER THE UPPER
MISSISSIPPI RIVER VALLEY. THE FRONT AND SHORTWAVE WILL NOT HAVE
MUCH MOISTURE TO WORK WITH AS THE DRY AIR ADVECTS IN FROM THE
SOUTHWEST...WITH A FAIRLY DEEP ELEVATED MIXED LAYER IN PLACE.
EXPECT TO SEE SOME SHOWERS AND ISOLATED THUNDERSTORMS AS THIS
FEATURE MOVES THROUGH. RATHER HIGH BASED ACTIVITY WITH CLOUD BASES
IN THE 8 TO 10KFT RANGE. GUSTY WINDS WOULD BE A CONCERN WITH ANY
SHOWER/STORM ACTIVITY THAT DEVELOPS. ANOTHER SHORTWAVE IS
EXPECTED TO MOVE OVER THE REGION DURING THE DAY ON THURSDAY.
AGAIN THE ELEVATED MIXED LAYER AND CAPPING WILL BE A FACTOR. 0-3KM
MUCAPE WILL CLIMB TO AROUND 2000 J/KG THURSDAY AFTERNOON BUT
QUICKLY WANES DURING THE AFTERNOON AS WEAK SURFACE HIGH PRESSURE
ATTEMPTS TO BUILD IN FROM THE EAST. WILL MAINTAIN A CHANCE OF
SHOWERS AND THUNDERSTORMS ON THURSDAY GIVEN THE SHORTWAVE MOVING
THROUGH.
.LONG TERM...FRIDAY THROUGH MONDAY
247 PM CDT MON JUL 30 2012
30.12 MEDIUM RANGE MODELS IN AGREEMENT FRIDAY INTO
SATURDAY...SHOWING A POTENT UPPER LEVEL TROUGH MOVING ACROSS THE
DAKOTAS AND PUSHING INTO THE UPPER MISSISSIPPI RIVER VALLEY. THE
TROUGH IS EXPECTED TO CLOSE INTO AN UPPER LOW OVER EASTERN NORTH
DAKOTA/NORTHERN MINNESOTA DURING THE DAY ON SATURDAY...PUSHING A
COLD FRONT ACROSS THE AREA. GIVEN THE STRONG DYNAMICS OF THIS SYSTEM
AND STRONG MOISTURE RETURN AHEAD OF IT...FOCUSED INTO THE FORECAST
AREA...A SEVERE WEATHER EVENT LOOKS POSSIBLE. TIMING OF THE FRONT
AND ANY MCS ACTIVITY AHEAD OF IT WILL HAVE AN IMPACT ON CONVECTION
OVER THE FORECAST AREA. EXACT DETAILS ARE UNCLEAR AT THIS TIME BUT
WILL HAVE TO KEEP A VERY CLOSE WATCH ON THE NEXT FEW FORECAST MODEL
RUNS. CURRENT THINKING IS THAT THE AREA COULD SEE AN MCS MOVE
THROUGH SATURDAY MORNING...WITH STORMS REDEVELOPING ALONG THE COLD
FRONT SATURDAY AFTERNOON. PLAN ON HIGHS ON FRIDAY RANGING FORM THE
LOWER 80S OVER NORTHERN WISCONSIN TO THE MID 80S ACROSS NORTHEAST
IOWA. LOOK FOR OVERNIGHT LOWS IN THE 60S. SLIGHTLY COOLER AIR WILL
MOVE IN BEHIND THE FRONT ON SUNDAY WITH HIGHS FALLING INTO THE 70S
TO LOWER 80S.
&&
.AVIATION...THROUGH 06Z WEDNESDAY
1149 PM CDT MON JUL 30 2012
HIGH PRESSURE WILL DOMINATE THE PATTERN THROUGH THE TAF PERIOD.
CLEAR SKIES ARE EXPECTED WITH WINDS LESS THAN 10 KNOTS. BOTH THE
31.02Z RAP AND 31.00Z NAM SHOWS WINDS ABOVE 10 KNOTS JUST ABOVE
THE SURFACE OVERNIGHT TONIGHT AND THIS SHOULD PRECLUDE ANY FOG FORMATION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
247 PM CDT MON JUL 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1101 AM CDT TUE JUL 31 2012
.DISCUSSION...
MOSTLY SUNNY AND WARM...BUT JUST A TAD COOLER THAN YESTERDAY/S PACE
MAINLY DUE TO A LITTLE MORE WIND. EVEN SOME GUSTS IN A SPOT OR TWO
OVER OUR TEXAS COUNTIES FROM THE SOUTHWEST. NO CHANGE TO EXPECTED
HIGHS FOR THE AFTERNOON AND ONLY MINOR CHANGES TO SKY. RAP MODEL
HAS PRECIP TO OUR EAST LATER TODAY SO WILL STICK WITH NO POP AT
THIS TIME. HOWEVER...WILL KEEP AN EYE FOR ANY SORT OF OUTFLOW TO
EMERGE OUT OF SE AR LATER THIS AFTERNOON. WE WILL UPDATE SOME PRODUCTS
AT NOON TO REDUCE SOME OF THE WORDING ASSOCIATED WITH THE HEAT
PRODUCTS.
&&
.AVIATION...
VERY LITTLE CHANGE TO COME IN THE 18Z PACKAGE...AS VFR CONDITIONS
ARE EXPECTED TO PERSIST. ISOLATED CONVECTION MAY DEVELOP MID TO
LATE AFTERNOON ACROSS SOUTH CENTRAL ARKANSAS INTO NORTH CENTRAL
LOUISIANA...BUT POPS ARE TOO SMALL TO MENTION WX IN KELD OR KMLU
TERMINAL FORECAST. ANY CONVECTION THAT DOES DEVELOPS SHOULD DIMINISH
DURING THE EARLY EVENING. SOUTH TO SOUTHWEST 5 TO 10 KTS WILL BE
COMMON ACROSS THE AREA...WITH NO VSBY CONCERNS EXPECTED. /11/
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE JUL 31 2012/
DISCUSSION...
VERY LITTLE CHANGE TO THE OVERALL FCST THIS PKG...AS THE UPPER
RIDGE CONTINUES TO CHURN OVER N TX. EXPECTING HEAT INDEX READINGS
OF 105+ FOR TODAY AND WEDNESDAY AREAWIDE...WITH SOME AREAS OF
N CENTRAL LA REACHING 110 TODAY. HEAT ADVISORY/EXCESSIVE HEAT
WARNING WILL CONTINUE AS IS FOR TODAY...AND HAVE EXTENDED THE HEAT
ADVISORY THROUGH WED. FOR TEMPS...HAVE STUCK CLOSE TO PERSISTENCE
FOR THE SHORT TERM...WHICH APPEARS TO BE RUNNING JUST ABOVE
GUIDANCE.
THE UPPER RIDGE IS FCST TO INCH WWD ENOUGH TOWARDS THE END OF THE
WORK WEEK TO ALLOW FOR WEAK DISTURBANCES TO RIDE ALONG THE ERN
PERIPHERY...BRINGING RAIN CHANCES TO N LA/SRN AR FOR THU/FRI...
AND TO THE REMAINDER OF THE REGION FOR THE WEEKEND/EARLY PART OF
NEXT WORK WEEK. THIS SHOULD ALSO PROVIDE SOME RELIEF FROM THE
HEAT...ALBEIT BY ONLY A FEW DEGREES OR SO. /12/
AVIATION...
VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE NEXT 24 HOURS.
ISOLATED CONVECTION MAY DEVELOP MID TO LATE AFTERNOON ACROSS SOUTH
CENTRAL ARKANSAS INTO NORTH CENTRAL LOUISIANA...BUT COVERAGE TOO
SMALL TO MENTION IN KELD OR KMLU TERMINAL FORECAST. ANY CONVECTION
THAT DOES DEVELOPS SHOULD DIMINISH DURING THE EARLY EVENING. SURFACE
WIND ACROSS THE REGION MOSTLY SOUTH TO SOUTHWEST 5 TO 10 KTS. /14/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 101 78 101 77 100 / 10 10 10 10 10
MLU 101 77 102 76 99 / 10 10 20 10 30
DEQ 102 73 103 73 103 / 10 10 10 10 10
TXK 102 78 103 76 103 / 10 10 10 10 10
ELD 101 75 102 76 100 / 10 10 20 10 20
TYR 101 79 101 78 101 / 10 10 10 10 10
GGG 101 77 101 78 101 / 10 10 10 10 10
LFK 99 77 99 77 98 / 10 10 10 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR THE FOLLOWING ZONES:
ARZ050-051-059>061-070>073.
LA...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR THE FOLLOWING ZONES:
LAZ001>006-010>012-017.
EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: LAZ013-014-018>022.
HEAT ADVISORY UNTIL NOON CDT TODAY FOR THE FOLLOWING ZONES:
LAZ013-014-018>022.
HEAT ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT WEDNESDAY FOR
THE FOLLOWING ZONES: LAZ013-014-018>022.
OK...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR THE FOLLOWING ZONES:
OKZ077.
TX...HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR THE FOLLOWING ZONES:
TXZ096-097-108>112-124>126-136>138-149>153-165>167.
&&
$$
24/11
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
913 AM EDT TUE JUL 31 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER NORTHERN NEW ENGLAND THROUGH
TODAY. LOW PRESSURE WILL APPROACH FROM THE WEST TODAY THROUGH
WEDNESDAY. AT THE SAME TIME...MID ATLANTIC LOW PRESSURE WILL MOVE
INTO THE CANADIAN MARITIMES. UNSETTLED CONDITIONS IN THE
ATMOSPHERE WILL LINGER INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...MINOR CHANGES WERE MADE BASED ON CURRENT OBSERVATIONAL
TRENDS. ALSO EXTENDED THE AREA OF SHOWERS FARTHER SOUTH INTO THE
FOOTHILLS FOR THIS AFTERNOON BASED ON HRRR GUIDANCE.
&&
PREVIOUS DISCUSSION...EXPECT ANY REMAINING VALLEY FOG TO QUICKLY
LIFT AFTER SUNRISE. OTHERWISE TODAY WILL BE MOSTLY QUIET...WITH A
GENERAL INCREASE IN CLOUDS FROM THE S. THE EXCEPTION MAY BE ON THE
PERIPHERY OF UPPER LEVEL RIDGING...WHERE DIURNAL HEATING MAY BE
ENOUGH TO SPARK A SHOWER OR THUNDERSTORM OVER THE HIGH TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
LOW PRESSURE WILL MEANDER NEWD UP THE COAST TONIGHT...PASSING
THOUGH THE GULF OF MAINE IN THE PROCESS. THERE REMAIN TWO CAMPS
AMONG MODEL GUIDANCE. THE NAM/GFS FAVOR A TRACK CLOSER TO THE
COAST...AND SUBSEQUENTLY MORE RAINFALL FOR COASTAL AREAS
OVERNIGHT. CONVERSELY...THE ECMWF...UKMET...AND GEM ALL MERELY
BRUSH THE COAST WITH SHOWERS. HAVE FAVORED AROUND A 1/3 BLEND OF
THE NORTH AMERICAN MODELS...WHICH PLACES LIKELY POP OFFSHORE
TONIGHT. THIS REPRESENTS A SLIGHT INCREASE IN POP FOR THE
COAST AND INTERIOR...WITH HIGH CHC POP AT TIMES TONIGHT.
LOW PRESSURE WILL DEPART TO OUR NE...WHILE A COLD FRONT APPROACHES
FROM THE W. THIS WILL LEAVE A SMALL BREAK IN THE ACTION...BEFORE
SHOWERS/THUNDERSTORMS ENTER THE WRN ZONES OF THE CWA. WITH LOW
PRESSURE OFF TO THE E...THE COLD FRONT WILL BE SLOW MOVING.
ATTM...EXPECTING THAT MUCH OF WED WILL SEE RAINFALL CONFINED TO
THE WRN HALF OF THE CWA.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE EXTENDED FORECAST WILL BE DOMINATED BY MAINLY DRY
CONDITIONS...WITH DIURNALLY DRIVEN SCATTERED SHOWERS AND
THUNDERSTORMS THROUGHOUT MUCH OF THE PERIOD.
AS COASTAL LOW PASSES TO OUR EAST WEDNESDAY MORNING...EXPECT
DRYING CONDS WITH OFFSHORE NORTHWESTERLY WINDS MUCH OF THE DAY.
THIS SUNSHINE WILL ALLOW FOR SUFFICIENT HEATING TO PRODUCE LATE
DAY SCATTERED SHOWERS/THUNDERSTORMS BUILDING FROM WEST TO EAST AS
A TROUGH APPROACHES FROM UPSTATE NEW YORK.
WEAK TROUGH IN THE UPPER ATMOSPHERE WILL ALLOW FOR MORE MAINLY
DIURNALLY DRIVEN SCATTERED -SHOWERS/THUNDERSTORMS ON THURSDAY AND
ALSO ON FRIDAY AS THE ATMOSPHERE BECOMES UNSTABLE DURING THE
MIDDLE PART OF THE AFTN EACH DAY. THE PASSAGE OF A WEAK SURFACE
BOUNDARY MAY ALLOW FOR SLIGHTLY HIGHER POPS BY FRIDAY AFTERNOON.
A MORE DYNAMICALLY DRIVEN SYSTEM MOVES OVER THE GREAT LAKES AND
THROUGH SOUTHERN CANADA OVER THE WEEKEND...BRINGING MORE SCATTERED
SHOWERS AND STORMS TO THE REGION. ONCE AGAIN...MUCH OF THE
EXTENDED FORECAST WILL BE DRY...WITH ANY GIVEN SHOWERS OR STORMS
LIKELY TO BE BRIEF AND SCATTERED ACROSS THE REGION.
YET MORE UNSETTLED WEATHER WILL BEGIN THE START OF NEXT WEEK AS
WELL.
USED A BLEND OF MEX AND GMOS NUMBERS FOR OVERNIGHT LOWS DURING
MUCH OF THE LONG RANGE.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...GENERALLY VFR CONDS EXPECTED TO PREVAIL. WILL SEE
PATCHY VALLEY FOG TONIGHT...THAT COULD REACH MVFR OR LOWER VSBYS
AND POSSIBLY CIGS. LOW PRESSURE DRIFTING UP THE COAST MAY SPREAD
MVFR CONDS INTO COASTAL TERMINALS LATE TONIGHT INTO WED MORNING.
LONG TERM...
MAINLY VFR EXPECTED THROUGH THE PERIOD WEDNESDAY
THROUGH SATURDAY. HOWEVER...A FEW BRIEF PERIODS OF MVFR TO IFR
POSSIBLE ESPECIALLY LATE AT NIGHT IN FOG/STRATUS...AS WELL AS
AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL APPROACH SCA THRESHOLDS LATE
TONIGHT INTO WED AS LOW PRESSURE CROSSES THE GULF OF MAINE.
LONG TERM...NO FLAGS EXPECTED THROUGH THE WEEKEND.
&&
.EQUIPMENT...
SPECIAL NOTE: COMMUNICATIONS CIRCUIT MAY HAVE BEEN FIXED AT KRKD
AND KLEW. OBSERVATIONS HAVE BEGUN FLOWING AGAIN THROUGH NORMAL
CHANNELS... AND IF THIS CONTINUES THE ISSUE MAY HAVE BEEN MORE
PERMANENTLY FIXED. TAF FOR KRKD WILL NO LONGER INCLUDE "AMD NOT
SKED" AND WILL RETURN TO THE NORMAL REMARKS OF "AMD LTD TO CLD VIS
AND WIND" UNLESS THE COMMUNICATIONS PROBLEM RETURNS.
GRAY MAINE /KGYX/ RADAR DATA WILL NOT BE AVAILABLE FOR SEVERAL
DAYS. THE DUAL POLARIZATION RADAR INSTALLATION AT THE NATIONAL
WEATHER SERVICE SITE IN GRAY MAINE IS IN PROGRESS. DURING
THE INSTALLATION AND FOLLOW UP TESTING OF THIS NEW EQUIPMENT...
RADAR DATA WILL BE UNAVAILABLE FROM THIS SITE. THIS COULD TAKE A
FEW MORE DAYS TO COMPLETE.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS PORTLAND OR
625 AM PDT TUE JUL 31 2012
.SYNOPSIS...THERE WILL BE LITTLE CHANGE IN WEATHER THE NEXT FEW DAYS
WITH MARINE CLOUDS PUSHING INLAND OVERNIGHT AND CLEARING IN THE
AFTERNOONS. HIGH PRESSURE AND WARMER TEMPERATURES ARE EXPECTED AT
THE END OF THE WEEK.
&&
.UPDATE...UPDATED AVIATION DISCUSSION.
.SHORT TERM...CLOUDS HAVE A LITTLE SLOWER TO DEVELOP AND PUSH INLAND
THIS MORNING...ESP IN THE S...BUT STILL A DECENT ONSHORE FLOW
COUPLED WITH THE LEFT OVER MARINE AIR MASS SHOULD FAVOR CLOUDS
MOSTLY FILLING IN THE INLAND VALLEYS THIS MORNING. SHORTWAVE SEEN IN
WATER VAPOR PICTURES NEAR 130 W WILL HAVE JUST SHALLOW MOISTURE TO
WORK WITH...SO A MENTION OF DRIZZLE NEAR THE COAST THIS MORNING
LOOKS ADEQUATE. A NEAR PERSISTENCE FORECAST APPEARS TO APPLY
OTHERWISE TODAY AND WED AS WSW FLOW CONTINUES ALOFT WITH A LOW LEVEL
ONSHORE FLOW. THE SHORTWAVE TODAY POTENTIALLY HELPS TO REINFORCE THE
MARINE LAYER AGAIN TONIGHT.
A TROUGH DIGGING DOWN THROUGH BC INTO SOUTHERN ALBERTA WED NIGHT AND
THU MARKS A LITTLE DIFFERENT TWIST TO THE FORECAST PATTERN. BOTH GFS
AND ECMWF PROMISE A LITTLE DEEPER LOW LEVEL MOISTURE WITH THE TAIL
END OF A COLD FRONT LATE WED NIGHT AND EARLY THU. LITTLE IN THE WAY
OF LIFT AVAILABLE WITH THIS MOISTURE HOWEVER...BUT WILL ADD A
MENTION OF SOME LIGHT RAIN OR DRIZZLE TO THE NW PART OF THE FORECAST
AREA ALONG WITH MORE CLOUDS FOR THE N PART OF THE AREA THU.
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS.
THE UPPER LEVEL TROUGH WILL MOVE INTO NORTHEAST BC LATE THU INTO FRI
WHILE SURFACE HIGH PRESSURE SETS UP OVER EASTERN OREGON. THIS
SCENARIO WILL ALLOW BRIEF OFFSHORE FLOW TO DEVELOP FRI AND FRI
NIGHT. PERSISTENT ONSHORE FLOW RETURNS FOR THE WEEKEND AS AN UPPER
LEVEL RIDGE MOVES OVER THE AREA...MAINTAINING THE NIGHT/MORNING
MARINE CLOUDS PATTERN ALONG THE COAST AND LOCALLY INLAND. EXPECT
TEMPERATURES TO REMAIN SLIGHTLY ABOVE NORMAL THROUGH NEXT WEEKEND
AND EARLY NEXT WEEK WITH INLAND HIGHS IN THE MID TO UPPER 80S AND IN
THE MID 60S ALONG THE COAST. MONSOONAL MOISTURE DRIFTS NORTH SUN
AFTERNOON...BRINGING A THREAT OF WEAK CONVECTION OVER THE CREST OF
THE LANE COUNTY CASCADES. HELD OFF ON PUTTING ANY MEASURABLE PRECIP
IN THE FORECAST RIGHT NOW...BUT WILL NEED TO KEEP AN EYE ON THE
OVERALL PATTERN. 27
&&
.AVIATION...STRATUS OFFSHORE IS WORKING ITS WAY BACK INLAND...WITH
THE INLAND STRATUS STARTING TO EXPAND EARLY THIS MORNING. LOCATIONS
WITH CLOUDS ARE VFR IN THE 3500-4000 FT RANGE...THOUGH SEEING SIGNS
OF LOWERING AT THE COAST AND A POCKET ALONG THE COLUMBIA RIVER
REPORTED AT KELSO (KKLS) AND OCCASIONALLY AROUND KTTD. EXPECT
STRATUS TO CONTINUE TO EXPAND FOR A LITTLE WHILE LONGER. ANOTHER
WEAK UPPER LEVEL DISTURBANCE WILL BE WEAKENING AS IT MOVES THROUGH
THE REGION EARLY TODAY...SO EXPECT LOW VFR/POSSIBLY MVFR CIGS WILL
AGAIN LINGER THROUGH LATE MORNING. VFR CONDITIONS SHOULD THEN RETURN
INLAND DURING THE EARLY AFTERNOON...AND MID TO LATE AFTERNOON AT THE
COAST.
KPDX AND APPROACHES...LATEST GFS/NAM MOS GUIDANCE STILL SUGGESTS THE
POSSIBILITY OF AN MVFR DECK...THOUGH SHORT TERM RAP AND LAMP
GUIDANCE SUPPORT OBSERVATIONS THAT THE TERMINAL SHOULD GENERALLY
REMAIN VFR WITH A DECK AROUND 3500 FT THIS MORNING...AND THAT THE
LOWER CLOUDS SHOULD MOSTLY REMAIN SCATTERED. CURRENT TAF HAS REMOVED
THE BROKEN MVFR CEILING AS CONFIDENCE IS LOWER NOW THAT SUNRISE IS
UPON US...BUT IT STILL POSSIBLE THE DECK WILL LOWER ENOUGH FOR A
SHORT TIME THIS MORNING. KMD
&&
.MARINE...HIGH PRESSURE REMAINS OVER THE THE WATERS WITH WEAK LOW
PRESSURE INLAND. AS THERMAL LOW PRESSURE OVER NORTHERN CALIFORNIA
STRENGTHENS...BRIEF BOUTS OF STRONGER NORTHERLY WINDS MAY DEVELOP IN
THE AFTERNOONS AND EVENINGS OVER THE NEXT FEW DAYS. EXPECT WIND
GUSTS NEARING 25 KT FROM TIME TO TIME LATER TODAY...MAINLY SOUTH OF
KONP...AND WILL CONTINUE THE MARGINAL SMALL CRAFT ADVISORY ALREADY
ISSUED. SEAS REMAIN VERY LOW THROUGH EARLY TOMORROW BUT AS NW
WINDS INCREASE TOMORROW AND WEDNESDAY AFTERNOON/EVENING...EXPECT
WIND WAVES TO ALSO INCREASE A BIT. LONG PERIOD SWELL FROM THE
SOUTHWEST WILL CONTINUE FOR THE NEXT FEW DAYS. KMD/JFP
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 2 PM THIS AFTERNOON TO
11 PM PDT THIS EVENING FOR COASTAL WATERS FROM CASCADE HEAD
TO FLORENCE OR OUT 10 NM-WATERS FROM CASCADE HEAD TO
FLORENCE OR FROM 10 TO 60 NM.
&&
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
950 AM EDT TUE JUL 31 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL KEEP THE AREA IN A FAVORED PATTERN FOR
SCATTERED SHOWERS AND STORMS INTO WEDNESDAY. A FRONT WILL APPROACH
THE AREA WEDNESDAY BEFORE DISSIPATING. FOR LATE WEEK...THE HEAT
RIDGE STARTS TO BE MORE OF INFLUENCE INTO OUR AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EDT TUESDAY...
ALREADY SEEING SHRA/TSRA DEVELOP OVER THE FAR WEST IN THE WEAK
CONVERGENCE ZONE/85H THETA-E RIDGE NORTH OF THE MCS PASSING ACROSS
THE SE STATES. EXPECT WITH CONTINUED HEATING WILL SEE CONVECTION
ORGANIZE MORE OVER THE SW AND GRADUALLY UNZIP TO THE NE ESPCLY
OVER THE MOUNTAINS AS THE NEXT PIECE OF UPPER TROFFINESS SLIDES
EAST. JUST HOW MUCH INTERACTION BETWEEN THE TWO OCCURS WILL
DETERMINE COVERAGE/STRENGTH OF STORMS GIVEN LOWER WET BULBS BUT
SLIGHTLY BETTER FLOW ALOFT THIS AFTERNOON. THINK NEXT SHORTWAVE
AND ASSOCIATED OUTFLOW TO THE NW PER VIS PICS SHOULD KEEP MOST OF
THAT COVERAGE TO THE WEST UNTIL LATE SO MAINLY LOOKING AT
SCATTERED MULTICELLULAR ACTION MAINLY MOUNTAINS WITH RENEWED
COVERAGE DRIVEN BY OUTFLOW. CURRENT FOG/STABILITY OUT EAST WILL
LIKELY LIMIT DEVELOPMENT EAST OF THE BLUE RIDGE AS COVERAGE THERE
LOOKS TO COME FROM CELLS HEATING OFF THE BLUE RIDGE LATER ON.
LATEST HRRR LOOKS TO SUPPORT THIS SCENARIO SO UPPED POPS TO LOW
LIKELYS IN A STRIP OUT EAST AND TRENDED DOWN TO JUST LOW CHANCE SE
PIEDMONT. STRONGER CELLS SHOULD AGAIN BE ABLE TO TAP SOME DRY AIR
ALOFT AND WITH COOLER AIR ALOFT UNDER THE TROF AXIS LIKELY MORE OF
A HAIL THREAT AS WELL SO KEEPING HWO MENTION. KEPT HIGHS CLOSER TO
THE COOLER MET MOS GIVEN CLOUDS/SHRA WEST IN SPOTS AND WIDESPREAD
STRATUS/FOG EAST TO INIT BUT STILL EXPECTING MOST IN THE 80S BY
LATE IN THE DAY.
AS OF 725 AM EDT TUESDAY...
TWO SHORTWAVES THIS MORNING CAUSING SHOWERS/TSRA OUTSIDE OUR
FORECAST AREA. MAIN ONE IS SOUTHWEST OF US IN THE TN VALLEY
CREATING SHRA/TSRA A COUPLE OF COUNTIES SOUTH OF WATAUGA...WITH
ANOTHER WEAK WAVE INDUCING SHOWERS IN WEBSTER COUNTY WV.
THE THREAT OF SHOWERS/STORMS INCREASES AROUND LATE MORNING...WITH
BEST THREAT IN THE MTNS...WITH ISOLATED COVERAGE IN THE PIEDMONT.
PREVIOUS DISCUSSION...
VERY LITTLE ON RADAR THIS MORNING WITH ONE LONE SHOWER UP NORTH OF
CHARLOTTESVILLE VA...WITH GENERALLY PC SKIES ACROSS THE FORECAST
AREA. MAIN AXIS OF PRECIP AND UPPER LEVEL ENERGY RESIDES ACROSS SRN
KY INTO TN THIS MORNING AND THIS SHORTWAVE IS ANTICIPATED TO SLIDE
SOUTHEAST TOWARD GA/SC LATER THIS MORNING. MODELS SHOWING SOME
AGREEMENT IN KEEPING THE BEST THREAT OF PRECIP ACROSS THE MTNS
TODAY...WITH BEST SUPPORT IN THE NC MTNS. HAVE GONE WITH 40/50 POPS
IN THE MTNS WITH 30 OUT EAST...BUT LOOKING AT LATEST LOCAL WRF
TRENDS AND WV LOOP LEADS ME TO THINK THAT COVERAGE ESPECIALLY EAST
OF THE BLUE RIDGE TODAY MAY BE ISOLATED. WENT A LITTLE CLOUDIER
TODAY IN THE MTNS...AND LEANED TOWARD THE COOLER MET/LOCAL MOS
NUMBERS HERE WITH LOWER-MID 80S FOR HIGHS AND EVEN 70S ACROSS THE NC
MTNS PER BETTER CONVECTION THREAT. THE EAST SHOULD REACH THE UPPER
80S.
TONIGHT...THE CONVECTION SHOULD WANE ACROSS THE AREA WITH DEPARTING
SHORTWAVE BUT WILL HAVE TO KEEP AN EYE ON THE CURRENT MCS AND
ASSOCIATED VORT/COLD FRONT MOVING ACROSS MICHIGAN AND SRN WISCONSIN THIS
MORNING. THE ECMWF/NAM TRACK THIS SYSTEM SOUTHEAST INTO THE WV MTNS
AFTER MIDNIGHT TONIGHT BUT THEN DISSIPATE IT. I AM INCLINED TO HAVE
AT LEAST CHANCE POPS IN THE WEST VIRGINIA/VA HIGHLANDS AREA WITH
SLIGHT CHANCE TO THE SOUTHEAST OF THIS AREA OVERNIGHT...THEN
TAPER IT OFF AROUND DAWN WED. KEPT LOWS IN THE 60S AREAWIDE
SIMILAR TO MOS NUMBERS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM EDT TUESDAY...
WEDNESDAY INTO WEDNESDAY NIGHT...A GENERAL PATTERN OF TROUGHINESS IN
THE EAST CONTINUES...WHILE AN UPPER RIDGE REMAINS PARKED OVER MUCH
OF THE TEXAS AND FOUR CORNERS REGION. A COLD FRONT ASSOCIATED WITH
THE EAST COAST TROUGH WILL SWING THROUGH THE AREA ON WEDNESDAY
BRINGING SCATTERED SHOWERS AND STORMS. THE LATEST DAY 2 CONVECTIVE
OUTLOOK FROM THE STORM PREDICTION CENTER SUGGESTS LAPSE RATES MAY
BE STEEP ENOUGH FOR SOME LOCALIZED ENHANCED CONVECTION THAT YIELDS
SEVERE WINDS AND HAIL. TEMPERATURES WILL TREND A BIT WARMER AS
COMPARED TO TUESDAY IN ADVANCE OF THE APPROACHING COLD FRONT.
DAYTIME CONVECTION WILL CONTINUE INTO THE EVENING HOURS WITH
ISOLATED SHOWERS AND STORMS CONTINUING ACROSS SOUTHERN AND EASTERN
PARTS OF THE AREA NEAREST THE EXITING COLD FRONT. ANTICIPATE
PRECIPITATION TO END BY MIDNIGHT WITH DECREASING CLOUD COVER. FOG
DEVELOPMENT WILL BE LIKELY DURING THE EARLY MORNING HOURS OF
THURSDAY...ESPECIALLY ACROSS THE MOUNTAINS VALLEYS AND THE RIVER
VALLEYS OF THE PIEDMONT.
THURSDAY INTO FRIDAY...THE EAST COAST TROUGH WILL FLATTEN A BIT AS
THE UPPER RIDGE SHIFTS EAST INTO THE LOWER MISSISSIPPI VALLEY.
ANTICIPATE A TREND TOWARD HOTTER TEMPERATURES. OTHER THAN SOME
ISOLATED SHOWERS AND STORMS IN THE NORTHERN MOUNTAINS OF NORTH
CAROLINA...DRY CONDITIONS ARE EXPECTED ON THURSDAY. BY FRIDAY...A
RETURN FLOW IS EXPECTED AS THE CENTER OF SURFACE HIGH PRESSURE
SHIFTS EAST A SHORTWAVE TROUGH MOVES EASTWARD WITHIN A ZONAL FLOW
THROUGH THE OHIO VALLEY. LOOK FOR THE DEVELOPMENT OF ISOLATED TO
SCATTERED SHOWERS AND STORMS ONCE AGAIN.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 230 PM EDT MONDAY...
WITH MORE PERSISTENT SOUTHERLY FLOW DEVELOPING INTO THE
WEEKEND...DEWPOINTS WILL BE ON THE RISE AND SO WILL INSTABILITY AS
RH INCREASES AT H7 AND H5. SHOWERS AND STORMS WILL BE MORE NUMEROUS
ON SUNDAY IN COMPARISON TO SATURDAY. ALTHOUGH H85 TEMPS MAY RISE A
FEW MORE DEGREES...MAX T WILL BE STUNTED BY MORE CLOUDS AND
THUNDERSTORMS. A COLD FRONT DROPS OUT OF THE GREAT LAKES EARLY NEXT
WEEK...SUCH THAT SHOWERS AND STORMS WILL BE MOST LIKELY ON MONDAY
AND MONDAY NIGHT. HIGH TEMPS SHOULD BE IN THE MIDDLE 80S TO LOWER
90S THROUGH THE PERIOD.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AS OF 730 AM EDT TUESDAY...
FOG/LOW CLOUDS THIS MORNING SHOULD DISSIPATE IN THE 12-14Z TIME
FRAME. VFR CONDITIONS EXPECTED ONCE THIS OCCURS AT ALL SITES.
THE MAIN THREAT OF STORMS WILL BE IN THE SOUTHWESTERN CWA ALONG
AND SOUTH OF A LINE FROM BLF-BCB. OVERALL...COVERAGE WILL BE
SCATTERED ELSEWHERE BUT CONFIDENCE IS HIGH THAT SHOWERS AND STORMS
WILL BE IN THE VICINITY OF ALL MOST TAF SITES IN THE AFTN SO KEPT
IT IN.
SHOULD SEE WEAKENING TREND TO CONVECTION THIS EVENING AS SHORTWAVE
PASSES. HOWEVER...ANOTHER SHORTWAVE UPSTREAM MAY BRING SHOWERS
INTO THE LWB/BLF AREA AFTER 06Z WED. CIGS MAY DROP AGAIN LATE TUE
NIGHT AS WELL AS VSBYS DEPENDING ON EXTENT OF RAINFALL...AND
CLEARING SKIES.
THE DAILY AFTERNOON AND EVENING THREAT OF SHOWERS AND
THUNDERSTORMS CONTINUES THROUGH THE WEEK BUT SHOULD BECOME MORE
ISOLATED WEDNESDAY AND THURSDAY. WEAK HIGH PRESSURE SETTLES IN
FROM THE WEST BY SATURDAY. OUTSIDE OF THIS MAINLY DIURNALLY DRIVEN
CONVECTION...THE ONLY OTHER FLIGHT WEATHER HAZARDS WOULD BE FROM
OVERNIGHT MVFR VALLEY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...JC
LONG TERM...KM
AVIATION...AMS/JH/WP
AREA FORECAST DISCUSSION
NWS DENVER CO
322 PM MDT TUE JUL 31 2012
.SHORT TERM...AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN
CENTERED OVER THE TEXAS AND OKLAHOMA PANHANDLES TONIGHT THROUGH
MIDDAY WEDNESDAY...THEN IT IS EXPECTED TO SHIFT TO THE SOUTH AS A
WEAK UPPER LEVEL DISTURBANCE BRUSHES ACROSS NORTHERN COLORADO LATE
IN THE DAY. THE FLOW ALOFT WILL BE MORE WEST/SOUTHWESTERLY
TONIGHT...THEN BE MORE WEST/NORTHWESTERLY ON WEDNESDAY. ONE ROUND
OF SHOWERS AND THUNDERSTORMS IS MOVING THROUGH THE DENVER METRO
AREA AT THIS TIME...WITH THE STRONGER STORMS PRODUCING UP TO ONE HALF
INCH OF RAINFALL...PENNY SIZE HAIL AND WIND GUSTS OF 35-40KTS.
THESE TSTMS SHOULD CONTINUE TO INITIATE MORE DEEP CONVECTION AS
THEY MAKE THEIR WAY EAST. THE THREAT OF A SEVERE TSTMS DEVELOPING
STILL EXISTS OVER THE NORTHEAST PLAINS LATE THIS AFTN AND EVNG.
WET MICROBURSTS COULD PRODUCE DAMAGING WINDS AND HAIL TO ONE INCH
IN DIAMETER. THE 15Z HRRR THIS MORNING...REFLECTED THE DEVELOPING
TSTMS FAIRLY WELL SO WL GO WITH ITS TREND. IT INDICATES MORE ISOLD
TSTM COVERAGE FM THE URBAN CORRIDOR WESTWARD UNTIL AROUND
03Z...THEN SWINGS ANOTHER AREA OF SHOWERS AND STORMS IN THE CWFA
OVERNIGHT BUT NOT AS INTENSE...SIMILAR TO WHAT OCCURRED THIS
MORNING. IF IT PANS OUT THEN THE SOUTHERN PORTION OF THE CWFA
SHOULD FAIR THE BEST WITH THE SECOND ROUND.
ON WEDNESDAY...PW VALUES REMAIN FAIRLY HIGH BUT WITH VALUES
SLIGHTLY LOWER IN THE 0.8-0.9 RANGE. STORM MOTIONS MORE NORTHWEST
TO SOUTHEAST. OVERALL CAPES NOT AS IMPRESSIVE AROUND 700 J/KG WITH
SOME CIN AS WELL THROUGH 21Z. A WEAK UPPER LEVEL TROUGH MAY
PROVIDE THE INITIATION FOR DEEP CONVECTION LATE WEDNESDAY AFTN.
WL GO WITH SCT COVERAGE IN THE HIGH COUNTRY WITH ISOLD POPS ACROSS
THE URBAN CORRIDOR AND ADJACENT PLAINS. OVERALL THE THREAT OF
TSTMS PRODUCING VERY HEAVY RAIN SHOULD BE LOWER THAT TODAY.
.LONG TERM...CHANGES LOOK TO BE IN STORE AS WE HEAD INTO THE
WEEKEND. WESTERLY FLOW OVER THE NORTHERN U.S. IS FORECAST TO DROP
A LITTLE FARTHER SOUTH WHICH WILL TEMPORARILY DISRUPT THE
MONSOONAL CIRCULATION OVER THE SOUTHWESTERN PART OF THE COUNTRY.
THE MAIN IMPACT FROM THIS WILL NOT ARRIVE UNTIL FRIDAY OR SATURDAY
SO THURSDAY MAY HAVE ONE MORE AFTERNOON OF SHOWERS OVER THE
MOUNTAINS AND OUT ACROSS THE PLAINS. TEMPERATURES WILL CONTINUE
CLIMBING INTO THE LOWER AND MID 90S ON THE PLAINS THROUGH FRIDAY.
ON SATURDAY...A DECENT SURFACE FRONT IS FORECAST TO DROP INTO THE
STATE AS AN UPPER TROUGH PASSES FROM WYOMING OUT ONTO THE NORTHERN
GREAT PLAINS. MUCH COOLER TEMPERATURES WILL RESULT...WITH A
PROBABLE END TO THE STREAK OF 90+ DAYS AT KDEN. THERE COULD BE
SOME MORNING CLOUDS AGAINST THE FOOTHILLS SATURDAY MORNING...BUT
THE REST OF THE DAY SHOULD BE FAIRLY STABLE ACROSS THE FORECAST
AREA. FOR THE REST OF THE WEEKEND AND EARLY NEXT WEEK...THE UPPER
RIDGE OVER THE SOUTHWESTERN U.S. WILL BEGIN TO RE-ESTABLISH A
MONSOONAL CIRCULATION. THE CHANCE OF SHOWERS AND THUNDERSTORMS
WILL CREEP BACK INTO THE FORECAST WITH HIGH TEMPERATURES ONCE
AGAIN CLIMBING INTO THE 90S ON THE PLAINS.
&&
.AVIATION...ISOLD TSTMS MOVING ACROSS SRN AND ERN PORTIONS OF THE
METRO AREA AT THIS TIME. WL GO WITH PRIMARILY VCTS THE REST OF THE
AFTN AND EVENING. A SECONDARY ROUND OF SHOWERS MAY SPREAD ACROSS
THE AREA LATE THIS EVENING AND OVERNIGHT...SIMILAR TO LAST NIGHT.
MUCH OF THIS MAY REMAIN MORE SOUTH OF THE DENVER AREA. OVERALL
EXPECTED VFR CONDITIONS BUT COULD SEE CIGS ON 050-060 WITH ANY
TSTMS THAT REDEVELOP LATER. SHOULD SEE NORTHWESTERLY WINDS THIS
AFTERNOON TRANSITION MORE EASTERLY BY THIS EVENING...THEN
SWITCHING TO DRAINAGE OVERNIGHT. IF DECENT CONVECTIVE SHOWERS
OCCUR OVERNIGHT OVER THE PALMER DIVIDE...THEN THE SOUTHERLY DRAINAGE
WINDS MAY AGAIN GET ENHANCED LATE TONIGHT AND WEDNESDAY MORNING.
&&
.HYDROLOGY...SLGT CHC OF TSTMS EXPECTED THE REST OF THIS AFTERNOON
AND EVENING. DO NOT ANTICIPATE THE STORMS TO BE AS STRONG AS THOSE
THAT OCCURRED EARLIER THIS AFTERNOON...SO BELIEVE THE THREAT OF
FLOODING RAINS IN THE BURN AREAS WILL BE LOW. COULD SEE SOME
REDEVELOPMENT OF SHOWERS AND STORMS AFTER 04Z THIS EVENING BUT
SUSPECT THIS AREAS OF SHOWERS AND STORMS WILL REMAIN ALONG AND
SOUTH OF THE INTERSTATE 70 CORRIDOR.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....DANKERS
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1222 PM CDT TUE JUL 31 2012
.AVIATION...
VFR WX WILL BE SEEN THROUGH 06Z/01 AS HIGH PRESSURE BUILDS INTO
THE WESTERN GREAT LAKES. AFT 06Z/01 THE POSSIBILITY EXISTS FOR
MVFR CONDITIONS TO DEVELOP DUE TO LIGHT WINDS. THE 18Z TAFS
REFLECT THIS TREND WITH VSBYS DROPPING TO 6SM. AFT 12Z/01 WINDS
WILL EVENTUALLY BECOME SOUTHERLY BY LATE MORNING. ..08..
&&
.PREV DISCUSSION... /ISSUED 1104 AM CDT TUE JUL 31 2012/
UPDATE...
A MINOR UPDATE TO THE FCST TO REFLECT CURRENT TRENDS HAS BEEN
ISSUED.
15Z SFC OBS INDICATE THE FRONTAL BOUNDARY RUNS FROM CHICAGO TO
ROUGHLY KSTJ. DEW POINTS HAVE POOLED INTO THE LOW AND MID 70S
AROUND THE FRONT. RAP TRENDS SLOWLY PUSH THE BOUNDARY SOUTH OF THE
CWFA DURING THE DAY SO DEW POINTS IN THE SOUTHERN PARTS OF THE
CWFA SHOULD SLOWLY DROP DURING THE AFTERNOON.
BASED ON THE 15Z OBS...MAX TEMPERATURES WERE ADJUSTED UPWARD
SLIGHTLY. THERE IS VERY WEAK TO NEUTRAL CAA OCCURRING BEHIND THE
FRONT BUT TEMPERATURES SHOULD STILL CLIMB THIS AFTERNOON.
THE QUESTION THEN BECOMES WHAT IS THE POSSIBILITY OF CONVECTION
THIS AFTERNOON. THERE IS A WEAK VORT MAX CURRENTLY MOVING FROM
WISCONSIN INTO NORTHEAST ILLINOIS BUT NO APPARENT TRIGGER FOR
LATER THIS AFTERNOON. THE CONVECTIVE TEMPERATURE ON THE 12Z
SOUNDING WAS 93. HOWEVER...RAP TRENDS INDICATE CONVECTIVE
TEMPERATURES CLIMBING ABOVE 100 FOR THE AFTERNOON HOURS.
SO...SOME DIURNAL CLOUDS SHOULD BE SEEN ACROSS THE AREA THIS
AFTERNOON BUT OVERALL DRY CONDITIONS SHOULD BE SEEN.
THE ADJUSTMENT OF TEMPERATURES AND DEW POINTS FOR TODAY INDICATES
THAT HEAT INDICES WILL BE IN THE 95 TO 100 DEGREE RANGE OVER
ROUGHLY THE SOUTHERN 40 PERCENT OR SO OF THE CWFA. AN SPS WILL BE
ISSUED TO BRING ATTENTION OF THE VERY WARM CONDITIONS EXPECTED FOR
THE AFTERNOON HOURS. ..08..
PREV DISCUSSION... /ISSUED 620 AM CDT TUE JUL 31 2012/
AVIATION...
A COLD FRONT EXTENDING ROUGHLY FROM CHICAGO TO MOLINE TO KANSAS
CITY THIS MORNING WILL CONTINUE TO PUSH SLOWLY SOUTH ACROSS THE
REGION. SURFACE AND LOW LEVEL WINDS WILL SHIFT TO THE NORTH
BEHIND THE FRONT. AREAS OF MVFR FOG THAT HAVE DEVELOPED WHERE
WINDS ARE CALM...MAINLY SOUTH OF HIGHWAY 34...WILL QUICKLY
DISSIPATE WITHIN AN HOUR OR TWO OF SUNRISE. OTHERWISE...VFR CONDITIONS ARE
EXPECTED TODAY AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION.
MVFR FOG WILL AGAIN BE POSSIBLE TONIGHT AS WINDS GO LIGHT AND
COULD EVEN DROP INTO IFR CATEGORY IN AREAS THAT RECENTLY RECEIVED
RAINFALL. /DMD/
PREV DISCUSSION... /ISSUED 309 AM CDT TUE JUL 31 2012/
SYNOPSIS...
A COLD FRONT IS CROSSING THE CWFA THIS MORNING...STRETCHING FROM
NEAR MILWAUKEE /KMKE/ TO SAVANNA /KSFY/ TO DES MOINES /KDSM/ AT
07Z. WITH THE SUPPORT OF AN UPPER SHORT WAVE...THE EASTERN PORTION
OF THIS BOUNDARY OVER SOUTHERN WI AND NORTHERN IL HAS TRIGGERED
CONVECTION. CONVECTION ALONG WESTERN PORTIONS OF THE FRONT IN OUR
CWFA HAS BEEN LIMITED TO ISOLATED AND WEAK ELEVATED POST FRONTAL
CELLS IN THE VICINITY OF THE 850MB FRONT. HOWEVER...DUE TO LIMITED
MOISTURE SUPPORT OR CONVERGENCE THEY HAVE AMOUNTED TO VERY LITTLE
AND CONTINUE TO WEAKEN AS WHAT MINIMAL UPPER SUPPORT WAS AVAILABLE
QUICKLY SHIFTS EAST OUT OF THE REGION.
SHORT TERM...TODAY AND TONIGHT...
MAIN FORECAST FOCUS IN THE SHORT TERM IS POTENTIAL FOR LINGERING
PRECIP CHANCES THIS MORNING THEN TEMPERATURES.
SURFACE FRONT IS PROGGED TO DROP INTO SOUTHERN PORTIONS OF THE CWFA
BY 15Z. AS MENTIONED ABOVE...WITH UPPER FORCING ALREADY RACING EAST
OUT OF THE REGION...WILL KEEP LOW /ISOLATED/ POPS FOR NORTHEASTERN
COUNTIES THROUGH 12Z THIS MORNING BUT NOTHING FOR TODAY. SURFACE
RIDGE SETTLES INTO THE AREA THIS AFTERNOON AND OVERNIGHT. NAM AND
UKMET ARE OUTLIERS...KEEPING THE SURFACE HIGH FARTHER NORTH THAN ALL
OTHER MODEL SOLUTIONS. THUS HAVE BASED TEMP FORECASTS THROUGH
TONIGHT ON THE FARTHER SOUTH SOLUTIONS...WITH LITTLE CHANGE IN
TODAYS HIGH TEMP FORECAST FROM PREVIOUS UPDATES AND A SLIGHT
LOWERING OF TONIGHTS LOW TEMP FORECAST. /DMD/
LONG TERM...WEDNESDAY THROUGH MONDAY...
LOOKS LIKE AUGUST WILL START OUT JUST LIKE JULY...HOT. FORECAST
FOCUS ON CONTINUED HOT TEMPERATURES REMAINDER OF THIS WEEK. THEN A
VIGOROUS SYSTEM ARRIVES ON SATURDAY FOLLOWED BY A BRIEF COOL DOWN.
WEDNESDAY THROUGH FRIDAY NIGHT...CONTINUED HOT THIS PERIOD WITH A
SMALL CHANCE FOR THUNDERSTORMS THURSDAY INTO THURSDAY NIGHT AS A
WEAK SHORT WAVE ARRIVES. MAX TEMPS WILL BE IN THE LOWER TO MID 90S
WITH MIN TEMPS IN THE UPPER 60S TO MID 70S.
SATURDAY AND SATURDAY NIGHT...ECM/GEM/GFS BRING A VIGOROUS TROUGH
INTO THE MIDWEST THAT IS CURRENTLY LOCATED NEAR THE ALEUTIANS.
STRONG MID LEVEL WINDS ARRIVING IN CONCERT WITH THE STRONG COLD
FRONT MAY MAKE FOR AN ACTIVE SEVERE WEATHER DAY...IF THE TIMING IS
RIGHT. THIS MAY ALSO PRODUCE A BETTER COVERAGE OF THUNDERSTORMS DUE
TO THE STRENGTH OF THE SYSTEM. WILL HAVE MAX TEMPS IN THE UPPER 80S
TO MID 90S BUT THIS WILL BE DETERMINED BY THE TIMING OF THE FRONT
AND CLOUD TRENDS.
SUNDAY AND MONDAY AND BEYOND...PASSAGE OF THE TROUGH AND COLD FRONT
USHERS IN COOLER AND MUCH LESS HUMID AIR MASS...FOR SUNDAY AND
MONDAY. MAX TEMPS IN THE 80S WITH LOWS IN THE 60S. HOWEVER THIS
COOLER AIR IS ONLY BRIEF AS OPERATIONAL MODELS BUILD A RIDGE ALOFT
BACK INTO THE MIDWEST FOR MUCH OF NEXT WEEK. 850 MB TEMPS WARM TO AT
LEAST +25C FOR MUCH OF THE WEEK WHICH WOULD SUPPORT AFTERNOON TEMPS
WELL INTO THE 90S TO LOWER 100`S AGAIN. THE LOCATION OF THE RIDGE
BASED ON CURRENT MODEL DATA SUGGESTS THE MCS ACTIVITY WOULD BE
ACROSS CENTRAL MN...NORTHERN WI AND NORTHERN LOWER MI. THIS
PERSISTENT RIDGE LOOKS SIMILAR TO WHAT WE HAD DURING THE END OF JUNE
AND FIRST WEEK IN JULY.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1104 AM CDT TUE JUL 31 2012
.UPDATE...
A MINOR UPDATE TO THE FCST TO REFLECT CURRENT TRENDS HAS BEEN
ISSUED.
15Z SFC OBS INDICATE THE FRONTAL BOUNDARY RUNS FROM CHICAGO TO
ROUGHLY KSTJ. DEW POINTS HAVE POOLED INTO THE LOW AND MID 70S
AROUND THE FRONT. RAP TRENDS SLOWLY PUSH THE BOUNDARY SOUTH OF THE
CWFA DURING THE DAY SO DEW POINTS IN THE SOUTHERN PARTS OF THE
CWFA SHOULD SLOWLY DROP DURING THE AFTERNOON.
BASED ON THE 15Z OBS...MAX TEMPERATURES WERE ADJUSTED UPWARD
SLIGHTLY. THERE IS VERY WEAK TO NEUTRAL CAA OCCURRING BEHIND THE
FRONT BUT TEMPERATURES SHOULD STILL CLIMB THIS AFTERNOON.
THE QUESTION THEN BECOMES WHAT IS THE POSSIBILITY OF CONVECTION
THIS AFTERNOON. THERE IS A WEAK VORT MAX CURRENTLY MOVING FROM
WISCONSIN INTO NORTHEAST ILLINOIS BUT NO APPARENT TRIGGER FOR
LATER THIS AFTERNOON. THE CONVECTIVE TEMPERATURE ON THE 12Z
SOUNDING WAS 93. HOWEVER...RAP TRENDS INDICATE CONVECTIVE
TEMPERATURES CLIMBING ABOVE 100 FOR THE AFTERNOON HOURS.
SO...SOME DIURNAL CLOUDS SHOULD BE SEEN ACROSS THE AREA THIS
AFTERNOON BUT OVERALL DRY CONDITIONS SHOULD BE SEEN.
THE ADJUSTMENT OF TEMPERATURES AND DEW POINTS FOR TODAY INDICATES
THAT HEAT INDICES WILL BE IN THE 95 TO 100 DEGREE RANGE OVER
ROUGHLY THE SOUTHERN 40 PERCENT OR SO OF THE CWFA. AN SPS WILL BE
ISSUED TO BRING ATTENTION OF THE VERY WARM CONDITIONS EXPECTED FOR
THE AFTERNOON HOURS. ..08..
&&
.PREV DISCUSSION... /ISSUED 620 AM CDT TUE JUL 31 2012/
AVIATION...
A COLD FRONT EXTENDING ROUGHLY FROM CHICAGO TO MOLINE TO KANSAS
CITY THIS MORNING WILL CONTINUE TO PUSH SLOWLY SOUTH ACROSS THE
REGION. SURFACE AND LOW LEVEL WINDS WILL SHIFT TO THE NORTH
BEHIND THE FRONT. AREAS OF MVFR FOG THAT HAVE DEVELOPED WHERE
WINDS ARE CALM...MAINLY SOUTH OF HIGHWAY 34...WILL QUICKLY
DISSIPATE WITHIN AN HOUR OR TWO OF SUNRISE. OTHERWISE...VFR CONDITIONS ARE
EXPECTED TODAY AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION.
MVFR FOG WILL AGAIN BE POSSIBLE TONIGHT AS WINDS GO LIGHT AND
COULD EVEN DROP INTO IFR CATEGORY IN AREAS THAT RECENTLY RECEIVED
RAINFALL. /DMD/
PREV DISCUSSION... /ISSUED 309 AM CDT TUE JUL 31 2012/
SYNOPSIS...
A COLD FRONT IS CROSSING THE CWFA THIS MORNING...STRETCHING FROM
NEAR MILWAUKEE /KMKE/ TO SAVANNA /KSFY/ TO DES MOINES /KDSM/ AT
07Z. WITH THE SUPPORT OF AN UPPER SHORT WAVE...THE EASTERN PORTION
OF THIS BOUNDARY OVER SOUTHERN WI AND NORTHERN IL HAS TRIGGERED
CONVECTION. CONVECTION ALONG WESTERN PORTIONS OF THE FRONT IN OUR
CWFA HAS BEEN LIMITED TO ISOLATED AND WEAK ELEVATED POST FRONTAL
CELLS IN THE VICINITY OF THE 850MB FRONT. HOWEVER...DUE TO LIMITED
MOISTURE SUPPORT OR CONVERGENCE THEY HAVE AMOUNTED TO VERY LITTLE
AND CONTINUE TO WEAKEN AS WHAT MINIMAL UPPER SUPPORT WAS AVAILABLE
QUICKLY SHIFTS EAST OUT OF THE REGION.
SHORT TERM...TODAY AND TONIGHT...
MAIN FORECAST FOCUS IN THE SHORT TERM IS POTENTIAL FOR LINGERING
PRECIP CHANCES THIS MORNING THEN TEMPERATURES.
SURFACE FRONT IS PROGGED TO DROP INTO SOUTHERN PORTIONS OF THE CWFA
BY 15Z. AS MENTIONED ABOVE...WITH UPPER FORCING ALREADY RACING EAST
OUT OF THE REGION...WILL KEEP LOW /ISOLATED/ POPS FOR NORTHEASTERN
COUNTIES THROUGH 12Z THIS MORNING BUT NOTHING FOR TODAY. SURFACE
RIDGE SETTLES INTO THE AREA THIS AFTERNOON AND OVERNIGHT. NAM AND
UKMET ARE OUTLIERS...KEEPING THE SURFACE HIGH FARTHER NORTH THAN ALL
OTHER MODEL SOLUTIONS. THUS HAVE BASED TEMP FORECASTS THROUGH
TONIGHT ON THE FARTHER SOUTH SOLUTIONS...WITH LITTLE CHANGE IN
TODAYS HIGH TEMP FORECAST FROM PREVIOUS UPDATES AND A SLIGHT
LOWERING OF TONIGHTS LOW TEMP FORECAST. /DMD/
LONG TERM...WEDNESDAY THROUGH MONDAY...
LOOKS LIKE AUGUST WILL START OUT JUST LIKE JULY...HOT. FORECAST
FOCUS ON CONTINUED HOT TEMPERATURES REMAINDER OF THIS WEEK. THEN A
VIGOROUS SYSTEM ARRIVES ON SATURDAY FOLLOWED BY A BRIEF COOL DOWN.
WEDNESDAY THROUGH FRIDAY NIGHT...CONTINUED HOT THIS PERIOD WITH A
SMALL CHANCE FOR THUNDERSTORMS THURSDAY INTO THURSDAY NIGHT AS A
WEAK SHORT WAVE ARRIVES. MAX TEMPS WILL BE IN THE LOWER TO MID 90S
WITH MIN TEMPS IN THE UPPER 60S TO MID 70S.
SATURDAY AND SATURDAY NIGHT...ECM/GEM/GFS BRING A VIGOROUS TROUGH
INTO THE MIDWEST THAT IS CURRENTLY LOCATED NEAR THE ALEUTIANS.
STRONG MID LEVEL WINDS ARRIVING IN CONCERT WITH THE STRONG COLD
FRONT MAY MAKE FOR AN ACTIVE SEVERE WEATHER DAY...IF THE TIMING IS
RIGHT. THIS MAY ALSO PRODUCE A BETTER COVERAGE OF THUNDERSTORMS DUE
TO THE STRENGTH OF THE SYSTEM. WILL HAVE MAX TEMPS IN THE UPPER 80S
TO MID 90S BUT THIS WILL BE DETERMINED BY THE TIMING OF THE FRONT
AND CLOUD TRENDS.
SUNDAY AND MONDAY AND BEYOND...PASSAGE OF THE TROUGH AND COLD FRONT
USHERS IN COOLER AND MUCH LESS HUMID AIR MASS...FOR SUNDAY AND
MONDAY. MAX TEMPS IN THE 80S WITH LOWS IN THE 60S. HOWEVER THIS
COOLER AIR IS ONLY BRIEF AS OPERATIONAL MODELS BUILD A RIDGE ALOFT
BACK INTO THE MIDWEST FOR MUCH OF NEXT WEEK. 850 MB TEMPS WARM TO AT
LEAST +25C FOR MUCH OF THE WEEK WHICH WOULD SUPPORT AFTERNOON TEMPS
WELL INTO THE 90S TO LOWER 100`S AGAIN. THE LOCATION OF THE RIDGE
BASED ON CURRENT MODEL DATA SUGGESTS THE MCS ACTIVITY WOULD BE
ACROSS CENTRAL MN...NORTHERN WI AND NORTHERN LOWER MI. THIS
PERSISTENT RIDGE LOOKS SIMILAR TO WHAT WE HAD DURING THE END OF JUNE
AND FIRST WEEK IN JULY.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 PM MDT TUE JUL 31 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 226 PM MDT TUE JUL 31 2012
15Z WATER VAPOR IMAGERY AND RAP ANALYSIS INDICATED LARGE
ANTICYCLONIC CIRCULATION ALOFT IN PLACE ACROSS THE SOUTHERN PLAINS
WITH CWA ON NORTHERN PERIPHERY OF CIRCULATION...WITH ANOTHER SHORT
WAVE TROUGH NOTED UPSTREAM ALONG THE UTAH AND COLORADO BORDER. 12Z
RAOBS INDICATED LITTLE CHANGE OVER THE PAST 24 HOURS ASIDE FROM SOME
LOW LEVEL DRYING AT LBF...WITH STEEP LAPSE RATES STILL OBSERVED
MAINLY BETWEEN H7 AND H6 AT BOTH DDC AND DNR.
MAIN SHORT TERM ISSUE WILL BE PRECIPITATION CHANCES LATE THIS
AFTERNOON AND EVENING.
TONIGHT...OVERALL PATTERN HAS CHANGED LITTLE FROM YESTERDAY WITH
LARGE SCALE RIDGE REMAINING TO THE SOUTH OF THE AREA AND SHORT WAVE
TROUGH MOVING OVER THE TOP OF THE RIDGE TONIGHT. OVERALL INSTABILITY
AND PW PROFILES SIMILAR AS WELL...WITH ONLY LOW LEVEL SHEAR BEING
NOTICEABLY WEAKER THAN YESTERDAY. WITH CU FIELDS DEVELOPING OVER THE
HIGHER TERRAIN AND NEAR MESOLOW NOTED OVER YUMA COUNTY...FAIRLY
LARGE LCLS IN PLACE FAVORING STRONG COLD POOLS AND MCS VECTORS
FAVORING EASTWARD MOTION INTO STRONGER INSTABILITY ACROSS THE CWA
THINK CHANCES FOR ANOTHER ROUND OF PRECIPITATION FAIRLY GOOD
ACROSS MUCH OF THE CWA...BUT UNTIL SOME ECHOES BEGIN TO DEVELOP
DOWNSTREAM AM HESITANT TO GO MUCH ABOVE THE 40-50% RANGE FOR POPS
ATTM. BEST TIMING FOR PRECIP LOOKS TO BE IN THE 00-04Z RANGE...BUT
WITH LINGERING WAA THROUGH THE NIGHT THINK AT LEAST A FEW WEAK
SHOWERS WILL CONTINUE THROUGH THE EARLY MORNING HOURS.
TEMPERATURES SHOULD BE FAIRLY SIMILAR TO WHAT OCCURRED LAST NIGHT
WITH WET BULB TEMPS WITH THUNDERSTORMS LIKELY BRINGING TEMPS DOWN
INTO THE 60S AS STORMS PASS RESULTING IN AT LEAST FEW LOCATIONS
SEEING LOW TEMPS OCCURRING EARLIER THAN NORMAL. WITH HIGH
PRECIPITABLE WATERS AND DEEP WARM CLOUD LAYER/FREEZING LEVEL
AROUND 17 KFT MSL...HEAVY RAIN WILL BE A THREAT BUT THINK OVERALL
MCS MOTION WILL BE FAST ENOUGH TO LIMIT ANY WIDESPREAD FLASH FLOOD
THREAT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 226 PM MDT TUE JUL 31 2012
H5 RIDGE WILL BEGIN TO FLATTEN WITH WESTERLY ZONAL FLOW
DEVELOPING OVER THE NORTHERN PLAINS. THIS WILL ALLOW FOR A SERIES OF
STRONGER SHORTWAVE TROUGHS TO MOVE THROUGH THE NORTHERN PLAINS...AND
ASSOCIATED COLD FRONTS TO DROP SOUTH TOWARDS THE CWA.
THE FIRST OF THESE FRONT WILL ARRIVE LATE WEDNESDAY EVENING.
INSTABILITY AND MOISTURE WILL REMAIN IN PLACE THROUGH THE DAY
WEDNESDAY...WITH INITIATION DURING THE AFTERNOON FOLLOWING SIMILAR
PATTERN AS THE LAST FEW NIGHTS IN THE WEST/NORTHWEST. ISOLATED
ACTIVITY SHOULD INCREASE IN COVERAGE DURING THE EVENING HOURS AS
THUNDERSTORMS BECOME MORE ORGANIZED UNDER WEAK FLOW. DIFFERENCE WILL
BE WITH LARGE SCALE ASSOCIATED WITH COLD FRONT IN THE EVENING
HOURS...WHICH COULD HELP WITH COVERAGE/STRENGTH OF THUNDERSTORMS.
SOUNDINGS APPEAR TO BE DRIER THAN THE LAST FEW DAYS...HOWEVER PWAT
VALUES OVER 1 INCH ARE STILL BEING ADVERTISED. DEPENDING ON THE
TIMING OF THE FRONT POSITION OF THE BEST THUNDERSTORM COVERAGE COULD
BE PUSHED TO THE SOUTH AND EAST QUICKER THAN CURRENTLY
ADVERTISED...SO I WAS NOT CONFIDENT ENOUGH TO GO HIGHER THAN 40 POPS
DURING THE EVENING.
WEAK SHORTWAVE TROUGHS WILL CONTINUE TO MOVE NORTH OF THE CWA ON
THURSDAY...HOWEVER WITH POST FRONTAL AIRMASS IN PLACE I HAVE
QUESTIONS TO HOW MUCH SURFACE BASE AND MIXED LAYER CAPE WILL
BE AROUND TO INITIATE THUNDERSTORMS. FOR NOW I HAVE KEPT POPS
LIMITED TO 20 RANGE THU/THU NIGHT. BETTER CHANCES RETURN FRIDAY
NIGHT WHEN A STRONGER TROUGH MOVES THROUGH THE NORTHERN PLAINS AND
ANOTHER COLD FRONT DROPS SOUTH ACROSS THE CWA. HAVE INCREASED POPS
TO CHANCE CATEGORY. GUIDANCE CONTINUES TO SHOW CHANCES LINGERING
THROUGH SATURDAY NIGHT AS ADDITIONAL WEAKER SHORTWAVES MOVE
THROUGH THE AREA ON NORTHERN EXTENT OF RIDGE. CONFIDENCE IS LOWER
ON THIS ACTIVITY...SO I LIMITED IT TO SLIGHT CHANCE.
TEMPERATURES ON WEDNESDAY AND THURSDAY SHOULD BE AROUND OR ABOVE
100F WITH GOOD WAA AHEAD OF APPROACHING COLD FRONTS. BEHIND THE
FRONT ON THURSDAY AFTERNOON TEMPS WILL BE IN THE MID TO UPPER
90S...WITH NEAR NORMAL TEMPERATURES ON SATURDAY IN THE UPPER 80S/LOW
90S. THE H5 RIDGE WILL BEGIN TO BUILD NORTH AGAIN AND STRENGTHEN
SUNDAY INTO EARLY NEXT WEEK AND BRING US BACK TO 100 DEGREE
TEMPERATURES AND A DRIER PATTERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1144 AM MDT TUE JUL 31 2012
MAIN CONCERN WILL ONCE AGAIN BE THUNDERSTORM CHANCES AS OVERALL
SIMILAR PATTERN REMAINS ACROSS THE TRI STATE AREA AS YESTERDAY.
GIVEN EXPECTED VERTICAL PROFILES...A PERIOD OF REDUCED VISIBILITY
IN HEAVY RAIN AND STRONG WIND GUSTS WILL ACCOMPANY ANY STORM THAT
FORMS. FOR THE TIME BEING...THINK TIMING WILL BE SIMILAR TO LAST
NIGHT WITH GLD BEING THE MOST LIKELY SITE TO BE
IMPACTED...ALTHOUGH CHANCES WILL BE A BIT HIGHER THAN YESTERDAY AT
MCK.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JRM
LONG TERM...DR
AVIATION...JRM
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
152 PM EDT TUE JUL 31 2012
.UPDATE...
ISSUED AT 150 PM EDT TUE JUL 31 2012
A FEW ISOLATED SHOWERS AND EVEN A THUNDERSTORM IN FLOYD COUNTY HAVE
DEVELOPED OVER THE PAST HOUR OR SO. SFC BASED CAPE IS HIGHEST IN THE
BIG SANDY REGION PER SPC MESOANALYSIS WITH LOW LEVEL LAPSE RATES
RATHER STEEP NO REAL INHIBITION. HOWEVER TRIGGERS ARE A BIT SUBTLE.
THIS SAME ANALYSIS DOES INDICATE SOME COOLING OCCURRING NEAR 500 MB
FROM A WEAK SHORTWAVE. MID LEVEL LAPSE RATES ARE GREATER TO THE NW OF
CURRENT CONVECTION CLOSER TO COLD POCKET ALOFT. THE OUTFLOW BOUNDARY
FROM CONVECTION EARLIER THIS AM LIES NW OF THE BLUEGRASS COUNTIES. AS
WE APPROACH PEAK HEATING...EXPECTED ISOLATES SHRA/TSRA TO
DEVELOP...WITH INSTABILITY PARAMETERS FAVORING THE SE COUNTIES OVER
THE NEXT COUPLE OF HOURS. THE OUTFLOW NW OF THE REGION MAY EITHER
REACH THE BLUEGRASS COUNTIES BY LATE IN THE AFTERNOON OR POSSIBLY
LEAD TO CONVECTIVE DEVELOPMENT THERE THAT COULD SENDS OUTFLOWS OUR
WAY. THE MOST RECENT HRRR SEEMS REASONABLE AND GENERALLY POINTS
TOWARD THE AFTERNOON ACTIVITY GENERALLY IN THE SE WITH THIS TENDING
TO DIE OFF IN THE EVENING WITH CONVECTION THEN POSSIBLE IN THE
BLUEGRASS. THIS SCENARIO IS GENERALLY IN LINE WITH THE PREVIOUS
GRIDS...SO ONLY SOME MINOR POP AND HOURLY GRIDS WERE TRENDED BASED ON
RECENT OBS.
UPDATE ISSUED AT 1018 AM EDT TUE JUL 31 2012
THE UPPER LEVEL DISTURBANCE THAT BROUGHT CONVECTION TO MAINLY THE SW
CWA CONTINUES TO DEPART FROM THE REGION WITH PERHAPS A FEW SPRINKLES
OR VERY LIGHT SHOWERS LEFT BEHIND IN THE SOUTHEAST. MEANWHILE...ANOTHER
UPPER LEVEL DISTURBANCE MOVING THROUGH THE GREAT LAKES WILL GENERALLY
PASS NORTH OF THE REGION TODAY...BUT WILL SEND A COLD FRONT TOWARD
THE REGION BY THE EVENING. MEANWHILE A RATHER WELL DEFINED OUTFLOW
BOUNDARY FROM SW INDIANA TO NEAR A CVG TO ILN TO CMH LINE IS EVIDENT
ON VIS SAT AND RADAR IMAGERY. ALTHOUGH CONVECTION HAS NOT RECENTLY
DEVELOPED ALONG THIS...THE 12Z NAM AND 6Z MODEL RUN DID NOT HANDLE
CONVECTION OVER EAST CENTRAL IL AND WEST CENTRAL IN ALL THAT WELL.
THIS LEADS TO UNCERTAINTY IN CONVECTIVE DEVELOPMENT THIS AFTERNOON...BUT
LEFTOVER BOUNDARIES...ARES OF DIFFERENTIAL HEATING BETWEEN CLOUDY AND
LESS CLOUDY AREAS THIS MORNING THROUGH EARLY THIS AFTERNOON AS WELL AS
THE APPROACHING OUTFLOW FROM THE NW MAY BE A FOCUS FOR CONVECTIVE
DEVELOPMENT IN THE AFTERNOON...GENERALLY FROM 18Z ON DURING PEAK
HEATING.
SKY COVER AND POPS WERE ADJUSTED A BIT IN THE NW AND THE SE TO
ACCOUNT FOR THE APPROACHING OUTFLOW BOUNDARY AND RADAR TRENDS IN THE
SE CWA. HOURLY TEMP AND DEWPOINT GRIDS WERE ALSO FRESHENED UP BASED
ON RECENT OBS.
UPDATE ISSUED AT 745 AM EDT TUE JUL 31 2012
DID A QUICK UPDATE FOR CURRENT CONDITIONS AND TRENDS. THE MAIN CHANGE
ENTAILS A FINE TUNING OF THE NEAR TERM POPS...SKY AND WX TO ACCOUNT
FOR THE ONGOING ISOLATED CONVECTION IN THE FAR SOUTH. UPDATES HAVE
BEEN SENT.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 315 AM EDT TUE JUL 31 2012
06Z SFC ANALYSIS SHOWS A DIFFUSE SURFACE PATTERN THROUGH EAST
KENTUCKY WITH SLIGHTLY LOWER PRESSURE FOUND TO THE SOUTHWEST WHERE A
BATCH OF SHOWERS AND OCCASIONAL THUNDERSTORMS ARE DROPPING INTO THE
TENNESSEE VALLEY. THESE ARE ASSOCIATED WITH THE LATEST SHORTWAVE TO
MOVE THROUGH THE REGION IN THE NORTHWEST FLOW ON THE EASTERN EDGE OF
THE SOUTHWEST RIDGE. IN ADDITION...OF NOTE...A BAND OF THUNDERSTORMS
ARE CURRENTLY CROSSING THE GREAT LAKES ALSO IN CONJUNCTION WITH A
SHORTWAVE...THOUGH A STRONGER ONE. THE CONVECTION AND ITS CLOUDS WILL
CONTINUE TO AFFECT THE SOUTHWEST PORTION OF THE AREA THROUGH THE
REMAINDER OF THE MORNING. TO THE NORTHEAST...MORE CLEAR SKIES ARE
FOUND AND THIS HAS BEEN PROMOTING DECENT RADIATIONAL COOLING WITH A
RIDGE TO VALLEY TEMPERATURE SPLIT ON THE ORDER OF 10 DEGREES UNDER
WAY. WITH LOW DEWPOINT DEPRESSIONS IN THE VALLEYS...DO ANTICIPATE
SOME FOG FORMING THERE TOWARDS DAWN.
THE MODELS ARE IN DECENT AGREEMENT ALOFT REPRESENTING THE EVOLUTION
OF THE MID LEVEL PATTERN THROUGH THE SHORT TERM PORTION OF THE
FORECAST. THEY ALL HAVE THE PERSISTENT RIDGE CENTERED OVER NORTHERN
TEXAS AND TROUGHING THROUGH THE NORTHEAST UNITED STATES. THIS WILL
MAINTAIN NORTHWEST FLOW OVER KENTUCKY ALONG WITH A STEADY STREAM
OF...MOSTLY WEAK...SHORTWAVES PASSING THROUGH THE OHIO VALLEY AND
SOUTHERN APPALACHIANS. THE MAIN WAVE...WITHIN THE BROADER TROUGH...
WILL SLOWLY DROP THROUGH THE GREAT LAKES EARLY THIS MORNING...MOVE
THROUGH THE OHIO VALLEY TODAY...AND PASS OVER THE SPINE OF THE
APPALACHIANS LATER TONIGHT WITH HEIGHTS SLIGHTLY RISING IN ITS
WAKE...ON WEDNESDAY. THE NAM IS MOST ROBUST WITH THIS FEATURE WHILE
THE OTHER MODELS ARE IN BETTER AGREEMENT ON A MORE SUBTLE PASSAGE.
EITHER WAY...THIS WAVE/TROUGH AXIS IS THE MOST SIGNIFICANT UPPER
LEVEL FEATURE IMPACTING EAST KENTUCKY THROUGH THE SHORT TERM. HAVE
FOLLOWED A BLEND OF THE MODEL GUIDANCE WITH A LEAN TOWARD A MODIFIED
VERSION...PRIMARILY WEAKER AND MORE BROAD BRUSHED...NAM12 GIVEN THE
NATURE OF THE MESOSCALE TO DOMINATE IN THIS TYPE OF SUMMER PATTERN.
SENSIBLE WEATHER WILL FEATURE THE CURRENT AREA OF CONVECTION
GRADUALLY DEPARTING TO THE SOUTH THIS MORNING...BUT LIKELY LEAVING
BEHIND SOME BOUNDARIES THAT THE DAILY INSTABILITY MAY BE ABLE TO TAKE
ADVANTAGE OF FOR ADDITIONAL CONVECTION LATER IN THE DAY. ATTENTION
WILL THEN TURN TO THE REMNANTS OF THE FRONT CURRENTLY CROSSING THE
GREAT LAKES AND ITS ARRIVAL INTO OUR VICINITY TOWARD EVENING. THIS
WILL HAVE THE POTENTIAL FOR ANOTHER BATCH OF CONVECTION WITH IT AS IT
PASSES TONIGHT...BUT IT WILL NOT BE CROSSING AT THE BEST TIMES FOR
GOOD INSTABILITY SO UNCERTAINTY OVER THE ACTUAL MAGNITUDE AND
PLACEMENT OF ANY RE/DEVELOPMENT TONIGHT REMAINS HIGH. THE TROUGHING
TO THE EAST WILL CONTINUE A BETTER RISK FOR CONVECTION INTO THE DAY
WEDNESDAY IN THE EASTERN PARTS OF THE CWA...WHILE SOMEWHAT DRIER...
BUT NOT COOLER...AIR MOVES INTO OUR WESTERN ZONES. FOR THE MOST PART
THE AREA WILL BE RATHER HUMID AND VERY WARM AGAIN TODAY AND WEDNESDAY
WITH THE COOLING EFFECT OF ANY CONVECTION...MCS OR OTHERWISE...RATHER
LIMITED.
FOR TEMPERATURES...FOLLOWED A BLEND OF PERSISTENCE...THE EXISTING GRIDS
AND THE MET MOS THROUGH THE SHORT TERM WITH ADJUSTMENTS FOR TERRAIN
EFFECTS TONIGHT. AS FOR POPS...ENDED UP MOST SIMILAR TO THE MET
NUMBERS THROUGH THE PERIOD.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 310 AM EDT TUE JUL 31 2012
MODELS CONTINUE TO COME INTO RELATIVELY GOOD ALIGNMENT WITH THE
EVOLUTION OF THE PATTERN THROUGH THE LONG TERM. THE PERIOD LOOKS TO
BEGIN WITH A SLOWLY DEPARTING TROF OVER THE NERN CONUS WHILE SFC
HIGH PRESSURE AND RIDGING ALOFT REMAIN THE DOMINANT FEATURES OVER
THE PLAINS. THIS SETUP WILL LEAVE ERN KY UNDER A NW FLOW THROUGH
MUCH OF THE WORK WEEK HOWEVER...GIVEN THE LIMITED MOISTURE BEING
ADVERTISED IN THE MODELS...WILL CONTINUE TO KEEP THE FCST DRY
THROUGH THURSDAY NIGHT.
BY FRIDAY...RETURN FLOW LOOKS TO COMMENCE AS HIGH PRESSURE
STRENGTHENS OVER THE WRN ATLANTIC AND AN AREA OF LOW PRESSURE BEGINS
WINDING UP OVER THE PLAINS. THE MID AND UPPER LEVELS ARE EXPECTED TO
BE TRANSITIONING INTO MORE OF A ZONAL FLOW OVER THE NRN HALF OF THE
CONUS LEAVING THE OHIO VALLEY STILL REPLETE WITH SHORT WAVE ENERGY
SKIRTING THE AREA ON FRIDAY AND SATURDAY...THUS RETURNING ERN KY TO
OUR REGULARLY SCHEDULED AFTERNOON/EVENING CHANCES FOR SHOWERS AND
THUNDERSTORMS.
ABOUT THIS TIME...ANOTHER ALBERTA CLIPPER LOOKS TO BEGIN RACING
ACROSS THE U.S./CANADIAN BORDER...USHERING A SFC SYSTEM THROUGH THE
GREAT LAKES OVER THE WEEKEND. THE ASSOCIATED COLD FRONT LOOKS TO
BEGIN APPROACHING OUR NECK OF THE WOODS AROUND THE TAIL END OF THE
PERIOD AND WITH A GOOD CONSENSUS EVEN THIS FAR OUT...WILL CONTINUE
WITH GOOD CHANCE POPS TO ROUND OUT THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 150 PM EDT TUE JUL 31 2012
INSTABILITY AS WELL AS A WEAK SHORTWAVE OR SHORTWAVES PASSING BY IN
THE FLOW AND AN APPROACHING COLD FRONT WILL MAKE ISOLATED CONVECTION
POSSIBLE THROUGHOUT SOUTHEAST KENTUCKY THROUGH INTO THE AFTERNOON
BEFORE DIMINISHING AROUND 22Z. LATER TONIGHT...AN APPROACHING COLD
FRONT FROM THE NORTH MAY KICK OFF A FEW STORMS AFTER OZ ACROSS
THE FORECAST AREA...ESPECIALLY NORTHERN AND EASTERN SECTIONS. WINDS
THROUGH THE PERIOD WILL BE LIGHT AND VARIABLE. GIVEN LOW CHANCES OF
CONVECTION...NO CB OR TSRA ARE FORECAST AT THE TAF SITES ATTM.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM....MB
AVIATION...JP
AREA FORECAST DISCUSSION
NWS GRAY ME
323 PM EDT TUE JUL 31 2012
.SYNOPSIS...
MID ATLANTIC LOW PRESSURE WILL MOVE ALONG THE NEW ENGLAND COAST
TONIGHT AND INTO THE CANADIAN MARITIMES WEDNESDAY. A WEAK COLD
FRONT WILL MOVE INTO THE REGION FROM THE WEST ON FRIDAY AND BECOME
STATIONARY THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
CUMULUS FIELD AND ISOLATED SHOWERS HAVE NOW DEVELOPED OVER COOS
COUNTY. THE HRRR MODEL INDICATES A FEW SHOWERS AND ISOLATED
THUNDERSTORMS WILL BE POSSIBLE OVER THE HIGHER TERRAIN FOR THE
REMAINDER OF THE AFTERNOON.
NORTHERN NEW ENGLAND IS CAUGHT IN BETWEEN TWO SYSTEMS...ONE
LOCATED TO OUR WEST AND THE OTHER TO OUR SOUTH. A COASTAL LOW
PRESSURE SYSTEM WAS DEEPENING NEAR LONG ISLAND THIS AFTERNOON AND
WILL MOVE ALONG THE NEW ENGLAND COASTLINE OVERNIGHT. MODELS ARE IN
BETTER AGREEMENT THAT COASTAL AREAS AND AREAS AS FAR INLAND AS THE
FOOTHILLS WILL SEE PRECIPITATION OVERNIGHT. THE MIDCOAST AREA AS
WELL AS THE ISLANDS LOOK TO RECEIVE THE HIGHEST QPF AMOUNTS.
CURRENTLY DO NOT EXPECT THUNDERSTORMS...BUT THERE COULD BE A FEW
STRIKES OFFSHORE CLOSER TO THE CORE OF THE SYSTEM. WIDESPREAD FOG
AND CLOUDY CONDITIONS WILL KEEP TEMPERATURES ON THE WARM SIDE
OVERNIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
THE COASTAL LOW WILL BE JUST OFFSHORE TOMORROW MORNING AND WILL
MOVE INTO THE CANADIAN MARITIMES BY EARLY AFTERNOON. AS SHOWERS
END OVER THE MIDCOAST REGION (ASSOCIATED WITH THE COASTAL LOW)
THEY WILL BEGIN TO CREEP INTO NEW HAMPSHIRE AND WESTERN MAINE
AHEAD OF THE COLD FRONT.
PW VALUES INCREASE TO NEAR 1.75 INCHES INDICATING POOLING MOISTURE
AHEAD OF THE APPROACHING COLD FRONT TO OUR WEST. FORECAST SKEW T
PROFILES SHOW SKINNY CAPE...WARM CLOUD LAYERS...AND VERY LIGHT
WINDS. THIS ALL POINTS TOWARDS POSSIBLE FLASH FLOODING PROBLEMS.
INSTABILITY WILL BE HIGH ENOUGH FOR SCATTERED THUNDERSTORMS.
HIGH TEMPERATURES SHOULD REACH THE UPPER 70S/LOWER 80S TOMORROW
WITH LOW TEMPERATURES IN THE UPPER 50S TO MID 60S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
COLD FRONT STALLS IN THE NORTHWESTERN PART OF THE AREA ON
THURSDAY... A SECOND AREA OF LOW PRESSURE PASSES OFFSHORE OF CAPE
COD DURING THE DAY. MOST OF THE RAIN WITH THIS LOW WILL STAY
OFFSHORE... BUT INSTABILITY AND LIFT ASSOCIATED WITH THE
DISSIPATING COLD FRONT AND A PASSING UPPER LEVEL SHORTWAVE TROUGH
MAY LEAD TO A FEW SHOWERS OR THUNDERSTORMS IN INLAND AREAS.
AS THE UPPER LEVEL TROUGH PUSHES EAST... A COLD FRONT WILL PUSH
SOUTHWARD INTO NORTHERN NEW ENGLAND ON FRIDAY... WITH SHOWERS AND
THUNDERSTORMS POSSIBLE ALONG AND AHEAD OF IT. THE FRONT STALLS AS
IT GETS CLOSER TO THE COAST ON SATURDAY AND WEAKENS.
LARGER TROUGH ALOFT PUSHES EASTWARD OUT OF THE GREAT LAKES SUNDAY
INTO MONDAY... WITH LIFT AHEAD OF THIS SYSTEM PROVIDING INCREASED
CHANCES FOR SHOWERS AND THUNDERSTORMS. THUNDERSTORMS WILL BE MOST
LIKELY ON MONDAY AHEAD OF A MORE PRONOUNCED COLD FRONT.
TEMPERATURES THROUGH THE PERIOD WILL REMAIN ABOVE NORMAL AS THE
JET STREAM STAYS NORTH AND WARM... MOIST AIR CONTINUES TO FLOW
INTO NEW ENGLAND.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SHORT TERM...GUSTY SOUTHERLY WINDS THIS AFTERNOON WITH VFR
CONDITIONS CONTINUING. LOWERING CEILINGS AND VISIBILITIES WILL
ARRIVE AS LOW PRESSURE MOVES ALONG THE NEW ENGLAND COASTLINE
TONIGHT. LIFR/IFR CONDITIONS LIKELY AT ALL TERMINALS JUST PRIOR TO
MIDNIGHT WITH SHOWERS EVERYWHERE EXCEPT KHIE...KLEB...AND KCON.
LONG TERM...GENERALLY VFR EXPECTED... BUT WITH INCREASING MOISTURE
LEVELS INTO THE WEEKEND... NOCTURNAL FOG WILL BECOME MORE AND MORE
LIKELY ESPECIALLY IN TRADITIONALLY FAVORED AREAS LIKE WHITEFIELD
AND LEBANON.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL FALL JUST SHORT OF SMALL CRAFT
THRESHOLDS LATE TONIGHT INTO WEDNESDAY AS LOW PRESSURE CROSSES
THE GULF OF MAINE.
LONG TERM...LOW PRESSURE PASSES EAST OF CAPE COD AND INTO NOVA
SCOTIA AGAIN ON THURSDAY. BUT WINDS SHOULD STAY BELOW 20 KT. HIGH
PRESSURE OVER THE ATLANTIC BRINGS A LIGHT SOUTHERLY FLOW THROUGH
THE WEEKEND.
&&
.EQUIPMENT...
THE DUAL POLARIZATION RADAR INSTALLATION AT THE NATIONAL
WEATHER SERVICE SITE IN GRAY MAINE IS IN PROGRESS. GRAY MAINE
/KGYX/ RADAR DATA WILL NOT BE AVAILABLE FOR ANOTHER DAY OR TWO
DURING THE INSTALLATION AND FOLLOW UP TESTING OF THIS NEW
EQUIPMENT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
HANES/KIMBLE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
353 PM EDT TUE JUL 31 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL REMAIN OVER THE MID ATLANTIC STATES
THROUGH WEDNESDAY...RESULTING IN DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS. THE TROUGH WILL LIFT OFF TO THE NORTHEAST THURSDAY
AND FRIDAY...BRINGING SLIGHTLY HOTTER CONDITIONS AND LOWER CHANCES
FOR PRECIPITATION.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WX ANALYSIS CONTINUES TO FEATURE WEAK AND RATHER DIFFUSE
COASTAL FRONT/SFC TROUGH DRAPED ACROSS NE NC COASTAL PLAIN.
ALOFT, UPPER LEVEL TROUGH REMAINS IN PLACE OVER SE CANADA,
EXTENDING SOUTH ACROSS THE EASTERN SEABOARD, WITH NUMEROUS WEAK
DISTURBANCES EMBEDDED WITHIN NW FLOW ALOFT. S/W RESULTING IN
COMPLEX OF TSTMS ACROSS THE SOUTHEAST POISED TO TRACK E THROUGH THE
CAROLINAS/GA OVER THE COURSE OF THE AFTN. ALREADY SEEING SHRAS
FORMING ALONG AXIS OF BEST OMEGA OVER THE WESTERN CWA. RAP SEEMS
TO HAVE A PRETTY GOOD HANDLE ON THIS ACTIVITY THUS FAR, PUSHING
THIS ACTIVITY TO THE SOUTH-SOUTHWEST THROUGH 00Z. MAIN HAZARD
THROUGH EARLY EVENING WILL BE WITH LCL HEAVY RAINFALL WITH SLOW
MOVING STORMS, AND WILL NOTE THIS IN HWO.
AS WITH THE PAST FEW DAYS, MUCH OF SHRA ACTIVITY SHOULD DIMINISH
AFTER SUNSET, WITH PARTIAL CLEARING THROUGH MIDNIGHT. DEPENDING ON
AMOUNT OF CLEARING, SOME PATCHY FOG IS POSSIBLE LATE, ESPECIALLY
INLAND. OTHERWISE, WARM AND MUGGY TONIGHT WITH EARLY MORNING LOWS
GENERALLY IN THE L70S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WEDNESDAY...
UPPER TROUGH DIGS/SHARPENS OVER THE REGION FOR WED, WITH ANOTHER
SHORTWAVE DROPPING SE FROM THE OHIO VLY AND PUSHING ACROSS THE
REGION WED AFTN. MEANWHILE, LLVL WINDS VEER AROUND TO THE S-SE.
GOOD MODEL AGREEMENT IN SPINNING UP A WEAK AREA LOW PRES ALONG THE
PERSISTENT COASTAL TROUGH OVER E GA/S SC EARLY WED...WITH THIS
FEATURE EXPECTED TO MOVE NE ALONG THE CAROLINA COAST THROUGH WED
AFTN/NIGHT. AT MINIMUM THIS WILL LIKELY RESULT IN A SIGNIFICANTLY
MORE CLOUDY DAY THAN PRESENT FORECAST WOULD SUGGEST, AND HAVE
ACCORDINGLY NUDGED TEMPS DOWNWARD ACROSS SE VA/NE NC COAST.
DOWNSLOPE FLOW ALOFT AND COMPRESSIONAL HEATING/SUBSIDENCE AHEAD OF
APPROACHING COLD FRONT TO THE NORTH WILL MAKE FOR A WARMER DAY
INLAND, WITH HIGHS ~90. WILL CARRY AT LEAST 30% POPS ONCE AGAIN
FOR MAINLY AFTN/EVENING TSTMS INLAND. HIGHS IN LOW-MID 80S EAST TO
UPR 80S TO LWR 90S WELL INLAND.
THURSDAY/FRIDAY...
UPPER TROUGH PIVOTS OFFSHORE FOR THURSDAY. IN ITS WAKE, FLOW
BECOMES QUASI-ZONAL ALOFT W/S-SW FLOW IN LOW LEVELS. GIVEN ANOTHER
WEAK SHORTWAVE TROUGH CROSSING THE AREA THU AFTN ALONG WITH
MODERATELY UNSTABLE MLCAPE VALUES AND INSTABILITY PARAMETERS, WILL
CARRY 20-30% POP FOR THU...WITH HIGHS INTO THE 90S WELL INLAND AND
UPR 80S NEAR THE COAST.
HEAT RIDGE OVER THE PLAINS TRANSLATES A BIT FARTHER EAST ON
FRIDAY AS UPPER FLOW FLATTENS OUT A BIT MORE OVER THE LOCAL AREA.
STRONGER RETURN FLOW WILL BRING ANOTHER VERY WARM DAY TO THE
REGION. ONCE AGAIN EXPECT MAINLY DIURNALLY DRIVEN LATE
AFTN/EVENING TSRA ALONG ANOTHER DEVELOPING NUMERICAL GUIDANCE HAS
BEEN RUNNING A BIT COOL IN THE DAY 3-4 PERIOD AND HV ACCORDINGLY
GONE JUST ABOVE WARMEST GUIDANCE, WHICH IS IN LINE WITH LCL
THICKNESS TOOL OUTPUT. EXPECT HIGHS INTO THE MID 90S INLAND/AROUND
90 COASTAL ZONES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
TYPICAL SUMMER TIME CONDITIONS EXPECTED FOR THE AREA. NEXT FRONT
APPROACHES THE AREA MONDAY AND TUESDAY. THIS FRONT LIKELY TO
DISSIPATE ACROSS THE AREA. MODELS FAIRLY SIMILAR WITH FRONTAL
BOUNDARY ON MONDAY AND TUESDAY AND THIS WILL BE THE BEST CHANCES
FOR THUNDERSTORMS. MAINLY WEAK FLOW FROM THE SOUTH EARLIER AND
THIS WILL GIVE A CHANCE OF MAINLY AFTERNOON THUNDERSTORMS.
TEMPERATURES WILL AGAIN BE MAINLY IN THE 90S FOR HIGHS AND 70S FOR
LOWS THROUGH THE PERIOD.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
SYNOPTIC SCALE TROUGH REMAINS IN PLACE OVER THE EASTERN SEABOARD
THIS AFTERNOON THROUGH THE DAY ON WEDNESDAY. WITH THAT TROUGH WILL
SEE SEVERAL PIECES OF SHORTWAVE ENERGY THAT WILL ROTATE THROUGH
THE TROUGH AND COULD PRODUCE SOME BANDS OF SHOWERS AND
THUNDERSTORMS. FOR THIS AFTERNOON...A WEAK SURFACE LOW IS LIFTING
NE ALONG THE COAST AND IS HELPING TO PRODUCE SOME NE FLOW ALONG
THE DELMARVA AND A LIGHT EASTERLY FLOW MAINLY EAST OF I-95. THIS
HAS LEFT A WEAK SFC BOUNDARY FROM JUST SOUTH OF ORF TO AKQ TO PTB
AND THEN NW TOWARD CHO. ALONG THIS BOUNDARY...SOME LOW LEVEL
CONVERGENCE IS PRODUCING SOME SCATTERED CONVECTION WHICH SHOULD
BUILD THROUGH THE AFTERNOON. THIS COULD PUSH SHOWERS INTO RIC/ORF
LATER THIS AFTERNOON. AT THIS TIME HAVE JUST HINTED AT THE SHOWERS
WITH VCTS. MORE CONVECTION IS DEVELOPING OVER THE DELMARVA AND
CONTINUES TO BUILDS...SO HAVE ADDED A MVFR TEMPO GROUP EXPECTING
THESE SHOWERS TO MOVE EAST.
AFTER 00Z...COULD SEE THE CONVECTION OVER THE MOUNTAINS TO ROLL
EAST...BUT EXPECT THAT IT WILL BE SCATTERED TO ISOLATED AND
WEAKENING SO HAVE NOT SHOWN THIS IN THE FORECAST. MAINLY EXPECT TO
SEE JUST SOME BROKEN MID TO HIGH LEVEL CLOUDS IN RESPONSE TO THE
DYING CONVECTION.
ON WEDNESDAY...SHOULD SEE A LIGHT SOUTHERLY FLOW DEVELOP AS A
DYING COOL FRONT MOVES ACROSS THE AREA AND REINFORCES THE SFC
FRONT JUST TO THE EAST OF THE AREA. THIS WILL HELP TO ENHANCE A
SFC LOW MOVING NE ALONG THE FRONT...WHICH WILL PRODUCE SHOWERS AND
TSTMS ACROSS NE NC AND THE TIDEWATER SO ORF AND ECG COULD SEE
SOME RESTRICTIONS DUE TO THE SHOWERS.
OUTLOOK...THE UPPER TOUGH SLIDES OFF THE COAST WED NIGHT INTO
THURSDAY MORNING AND WITH IT EXPECT VFR CONDITIONS TO PREVAIL INTO SUNDAY.
&&
.MARINE...
NO HEADLINES IN THE SHORT TERM TNGT THRU THU. WEAK LO PRES MOVNG AWAY
OFF THE NJ CST TNGT...WITH ESE WNDS LESS THAN 15 KT TURNING TO THE S
10 KT OR LESS OVRNGT INTO WED MORNG. ANOTHER WEAK LO PRES AREA WILL
MOVE UP OFF THE MID ATLC CST LATE WED NGT THRU THU MORNG...TURNING
WNDS 15 KT OR LESS TO THE NE...N THEN NW. OTHRWISE...EXPECT MAINLY S
OR SW WNDS LESS THAN 15 KT FOR MUCH OF THE FCST PERIOD TNGT THRU
SUN. WAVES 1 TO 3 FT AND SEAS 2 TO 4 FT.
&&
.CLIMATE...
PRELIMINARY DATA FOR JULY SHOWING THAT ALL 3 MAIN CLIMATE SITES
(RIC/ORF/SBY) WILL EASILY RANK IN THE TOP 10 WARMEST ON RECORD.
RICHMOND LIKELY TO BE 2ND WARMEST...NORFOLK LIKELY TO BE 5TH
WARMEST...AND SBY LIKELY TO BE THE WARMEST ON RECORD. WHEN CLIMATE
DATA IS AVAILABLE LATER THIS EVENING A PNS WILL BE ISSUED.
&&
.EQUIPMENT...
KDOX RADAR IS DOWN DUE TO A FAILED AZIMUTH MOTOR. PARTS HAVE BEEN
ORDERED. HOWEVER, REPAIRS MAY TAKE SEVERAL DAYS TO COMPLETE. RETURN
TO SERVICE IS NOT KNOWN AT THIS TIME. FURTHER DETAILS WILL BE
PASSED ALONG AS THEY BECOME AVAILABLE.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...ALB
LONG TERM...JAB
AVIATION...ESS
MARINE...TMG
CLIMATE...AKQ
EQUIPMENT...AKQ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
332 PM EDT TUE JUL 31 2012
.SYNOPSIS...
INCREASING HUMIDITY AND A SLOW SOUTHEASTBOUND LOW PRESSURE SYSTEM
WILL FUEL SCATTERED SHOWERS AND THUNDERSTORMS INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
PER RECENT SURFACE AND RADAR DATA, HAVE MENTION OF THUNDERSTORMS
ACROSS THE APPALACHIAN MOUNTAINS, WITH GUSTY WIND, HAIL, FREQUENT
LIGHTNING, AND HEAVY RAIN.
FARTHER WEST, HAVE MAINTAINED A FORECAST OF INCREASING COVERAGE OF
THUNDERSTORMS THROUGH EARLY EVENING. HAVE ALSO ADDED MENTION OF
GUSTY WIND, HAIL, FREQUENT LIGHTNING, AND HEAVY RAIN.
RECENT SATELLITE DATA SHOWS CUMULONIMBUS DEVELOPING WITHIN THE
BAND OF ALTOCUMULUS, ASSOCIATED WITH LIFT FROM LOW PRESSURE TROUGH
CONTINUING TO MOVE SLOWLY SOUTHEASTWARD ACROSS NORTHWEST
PENNSYLVANIA AND THE STATE OF OHIO. THIS SHOULD BE FOCUS OF
THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON AS SHOWN BY 00Z
WRF-NMM AND RECENT HRRR MODEL OUTPUT.
REGARDING HEAVY RAINFALL POTENTIAL, PRECIPITABLE WATER IS NOW UP
TO 1.4 INCHES. RECENT FLASH FLOOD GUIDANCE SUGGESTS 2 INCHES OF
RAIN IN LESS THAN 3 HOURS NEEDED FOR FLOODING PROBLEMS TO DEVELOP.
EXPECT THUNDERSTORM CHANCES TO DECREASE OVERNIGHT DUE TO THE
EVENTUAL OVERNIGHT PASSAGE OF THE LOW PRESSURE TROUGH AND THE
STABILIZING EFFECTS OF NIGHTTIME SURFACE LAYER COOLING.
WITH EXPECTED ADDED RAINFALL, HAVE ADDED LATE NIGHT PATCHY FOG,
MORE WIDESPREAD ACROSS THE WV-MD MOUNTAINS AND PA LAUREL
HIGHLANDS.
MADE MINIMAL TEMPERATURE ADJUSTMENTS BASED ON RECENT GFS LAMP AND
MOS OUTPUT.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
HAVE MAINTAINED A CHANCE OF THUNDERSTORMS DAYTIME WEDNESDAY, MORE
SO DUE TO LATENT INSTABILITY ASSOCIATED WITH THE LINGERING HUMID
SURFACE LAYER CONDITIONS.
HIGH PRESSURE SUBSIDENCE SHOULD PROVIDE MORE STABILIZATION
THURSDAY AND FRIDAY, AND THUS DRY CONDITIONS, DESPITE SURFACE DEW
POINTS SHOWING SLIGHTLY MORE HUMID THAN NORMAL CONDITIONS.
FORECASTED WARMER AFTERNOON HIGHS THURSDAY AND FRIDAY THAN
WEDNESDAY. IN FACT, GFS AND ECMWF MOS SHOW HIGHS OF 90 CAN OCCUR
ACROSS LOWER ELEVATIONS, PARTICULARLY FRIDAY.
EARLY MORNING LOWS WILL BE SLIGHTLY WARMER THAN NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONTINUED HUMID AND VERY WARM CONDITIONS WILL EVOLVE INTO UNSETTLED
CONDITIONS THIS PERIOD.
CONSENSUS OF MODELS SHOW A STRONG UPPER LEVEL TROUGH AND CLOSED
SURFACE LOW TRACKING, EAST ALONG THE CANADIAN BORDER THIS WEEKEND
THAT WILL PASS EASTWARD THROUGH THE EASTERN GREAT LAKES MONDAY.
INSTABILITY WILL BE INCREASED AS ALREADY HUMID CONDITIONS WILL BE
FURTHER AUGMENTED BY LOW LEVEL SOUTHERLY WINDS PROVIDING AN
ADDITIONAL INFLUX OF GULF MOISTURE. SO EXPECT A DECENT CHANCE OF
THUNDERSTORMS ACROSS THE UPPER OHIO VALLEY THIS WEEKEND INTO
MONDAY.
SURFACE HIGH PRESSURE IS PROGGED TO PROVIDE DRY, STABLE CONDITIONS
TUESDAY.
FORECASTED TEMPERATURES TO CONTINUE AT LEAST SLIGHTLY WARMER THAN
NORMAL BASED ON BLEND OF RECENT GFS AND ECMWF MOS AND NAEFS MEDIAN
VALUES.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/..
EXPECT INCREASE IN COVERAGE OF THUNDERSTORMS AND POTENTIAL OF
MAINLY MVFR RESTRICTIONS ACROSS THE UPPER OHIO VALLEY THROUGH
EARLY EVENING. SCATTERED THUNDERSTORMS NEAR THE MOUNTAINS WILL BE
JOINED BY A DEVELOPING BAND OF THUNDERSTORMS SHOWN BY RECENT HRRR
MODEL OUTPUT. SO TAFS CONTINUED TO HAVE MENTION OF TEMPO MVFR RESTRICTIONS
IN THUNDERSTORMS FOR ALL TAFS THROUGH 02Z.
HAVE LIKEWISE MAINTAINED MENTION OF A SECOND ROUND OF MAINLY MVFR
RESTRICTIONS DUE TO LATE NIGHT FOG. THUNDERSTORMS WITH POTENTIAL
RESTRICTIONS ARE STILL POSSIBLE ON WEDNESDAY, UNTIL AN UPPER LEVEL
TROUGH EXITS EAST OF THE MOUNTAINS.
OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY...
EXPECT VFR AND GENERALLY DRY CONDITIONS FOR THURSDAY AND FRIDAY.
RESTRICTIONS WILL BE POSSIBLE AGAIN WITH THUNDERSTORMS SATURDAY AND
SUNDAY, AS ANOTHER LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
203 PM EDT TUE JUL 31 2012
.SYNOPSIS...
INCREASING HUMIDITY AND A SLOW SOUTHEASTBOUND LOW PRESSURE SYSTEM
WILL FUEL SCATTERED SHOWERS AND THUNDERSTORMS INTO WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
PER RECENT SURFACE AND RADAR DATA, HAVE ACCELERATED INCREASE COVERAGE
OF THUNDERSTORMS ACROSS THE APPALACHIAN MOUNTAINS, AND HAVE ALSO
ADDED MENTION OF GUSTY WIND, HAIL, FREQUENT LIGHTNING, AND HEAVY
RAIN.
ELSEWHERE, HAVE SLOWED INCREASE IN COVERAGE OF THUNDERSTORMS,
ALTHOUGH MAINTAINED MENTION OF LIKELY THUNDERSTORMS THIS EVENING
AREA WIDE. RECENT SATELLITE DATA SHOWS ALTOCUMULUS, ASSOCIATED WITH
LIFT FROM LOW PRESSURE TROUGH CONTINUING TO MOVE SLOWLY
SOUTHEASTWARD ACROSS LAKE ERIE AND THE STATE OF OHIO. THIS SHOULD
BE FOCUS OF THUNDERSTORM DEVELOPMENT LATE THIS AFTERNOON AS SHOWN
BY 00Z WRF-NMM AND RECENT HRRR MODEL OUTPUT.
SPC CONTINUES TO PROJECT RESTRICTED POTENTIAL OF SEVERE
DEVELOPMENT, MORE SO FROM WIND THAN HAIL.
REGARDING HEAVY RAINFALL POTENTIAL, PRECIPITABLE WATER IS NOW UP
TO 1.4 INCHES. RECENT FLASH FLOOD GUIDANCE SUGGESTS 2 INCHES OF
RAIN IN LESS THAN 3 HOURS NEEDED FOR FLOODING PROBLEMS TO DEVELOP.
EXPECT THUNDERSTORM CHANCES TO DECREASE OVERNIGHT DUE TO THE
EVENTUAL OVERNIGHT PASSAGE OF THE LOW PRESSURE TROUGH AND THE
STABILIZING EFFECTS OF NIGHTTIME SURFACE LAYER COOLING.
MADE MINIMAL TEMPERATURE ADJUSTMENTS BASED ON RECENT GFS LAMP AND
MOS OUTPUT.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
HAVE MAINTAINED A CHANCE OF THUNDERSTORMS DAYTIME WEDNESDAY, MORE
SO DUE TO LATENT INSTABILITY ASSOCIATED WITH THE LINGERING HUMID
SURFACE LAYER CONDITIONS.
HIGH PRESSURE SUBSIDENCE SHOULD PROVIDE MORE STABILIZATION
THURSDAY AND FRIDAY, AND THUS DRY CONDITIONS, DESPITE SURFACE DEW
POINTS SHOWING SLIGHTLY MORE HUMID THAN NORMAL CONDITIONS.
FORECASTED WARMER AFTERNOON HIGHS THURSDAY AND FRIDAY THAN
WEDNESDAY. IN FACT, GFS AND ECMWF MOS SHOW HIGHS OF 90 CAN OCCUR
ACROSS LOWER ELEVATIONS, PARTICULARLY FRIDAY.
EARLY MORNING LOWS WILL BE SLIGHTLY WARMER THAN NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
SLIGHTLY UNSETTLED PATTERN FOR THE LONG TERM PORTION OF THE
FORECAST. TRENDED AWAY FROM THE ECMWF...WHICH SEEMED TO HANG A
FRONT OVER THE REGION MUCH LONGER THAN OTHER DETERMINISTIC/ENSEMBLE
MODELS. BEST CHANCE FOR RAIN APPEARS TO BE SUNDAY INTO SUNDAY
NIGHT...WITH SOME TIMING CONSENSUS FOR FRONT FROM GFS/CMC/GEFS.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL BEFORE THE FRONTAL
PASSAGE...RETURNING TO NORMAL BY SUNDAY AND MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
HAVE INCLUDED A TEMPO GROUP FOR MAINLY MVFR RESTRICTIONS IN
THUNDERSTORMS STARTING AROUND 19Z IN THE NORTH AND 23Z IN THE
SOUTH AS RECENT MODEL OUTPUT CONTINUES TO SHOW A BAND OF
THUNDERSTORMS MOVING SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY.
HAVE INCLUDED MENTION OF A SECOND ROUND OF MAINLY MVFR RESTRICTIONS
DUE TO LATE NIGHT FOG.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...
SCATTERED SHOWERS/STORMS WITH POSSIBLE RESTRICTIONS CAN OCCUR
WEDNESDAY. THEN EXPECT VFR AND GENERALLY DRY CONDITIONS FOR
THURSDAY AND FRIDAY. RESTRICTIONS WILL BE POSSIBLE AGAIN IN
SCATTERED SHOWERS/STORMS SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
328 PM CDT TUE JUL 31 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...
CRITICAL FIRE WEATHER CONDITIONS IN SOUTHWESTERN NORTH DAKOTA WITH A
RED FLAG WARNING IN EFFECT THROUGH EARLY EVENING. SEE FIRE WEATHER
SECTION BELOW.
THE NEXT AREA OF CONCERN IS ANTICIPATED THUNDERSTORM DEVELOPMENT
THIS AFTERNOON/EVENING.
CURRENTLY...A SURFACE FRONT/TROUGH EXTENDED FROM A LOW AT THE
SOUTHERN SASKATCHEWAN/MANITOBA BORDER TO BETWEEN WILLISTON/MINOT TO
JUST EAST OF DICKINSON...TO NEAR HETTINGER. SURFACE TEMPERATURES
WERE MAINLY IN THE UPPER 90S SOUTHWEST TO UPPER 80S IN THE JAMESTOWN
AREA. THE MID-LEVEL ATMOSPHERIC CAP WAS STRONG AND INHIBITING ANY
THUNDERSTORM DEVELOPMENT.
THE BEST CHANCE FOR THUNDERSTORM DEVELOPMENT IS ALONG THE SURFACE
FRONT/TROUGH. LATEST MODELS WERE IN DISAGREEMENT ON SURFACE WIND
PATTERN...TROUGH PLACEMENT...AND UPPER LEVEL IMPULSE TRACK/PLACEMENT
- AND ULTIMATELY DISAGREED ON THUNDERSTORM DEVELOPMENT. LATEST
THINKING IS THAT ANY UPPER LEVEL IMPULSE FOR THIS AFTERNOON IS NOW
IN NORTHERN MINNESOTA AND WILL LIKELY NOT AFFECT NORTH DAKOTA.
THINKING THAT THE BEST MODEL TO FOLLOW IS THE LATEST 18Z HRRR WHICH
DEVELOPS THUNDERSTORMS ALONG THE SURFACE TROUGH THIS EVENING
BEFORE/NEAR SUNSET. THIS SCENARIO APPEARS TO BE THE MOST PLAUSIBLE
AS THERE DOES NOT APPEAR TO BE ANY UPPER LEVEL KICKER TO DISTURB THE
MID LEVEL THERMAL CAP.
WITH THIS IN MIND...HAVE KEPT THE BEST CHANCES OF EVENING
THUNDERSTORMS ALONG AND EAST OF A LINE FROM BOTTINEAU TO
BISMARCK/MANDAN TO WESTERN GRANT/SIOUX COUNTIES. AFTER MIDNIGHT
CHANCES ARE MAINLY CONFINED TO THE JAMES RIVER BASIN.
A SLIGHTLY COOLER DAY ON WEDNESDAY WITH MAINLY NORTH/NORTHWEST WINDS
WITH HIGHS FROM THE MID 80S NORTH TO LOWER 90S SOUTH. KEPT A SLIGHT
CHANCE OF THUNDERSTORMS...MAINLY ACROSS THE NORTH...WITH AN UPPER
LEVEL IMPULSE MOVING EAST ALONG THE CANADIAN BORDER.
ANOTHER SLIGHT CHANCE OF THUNDERSTORMS WEDNESDAY NIGHT ACROSS THE
FORECAST AREA...WITH A WESTERLY ZONAL FLOW ALOFT AND WEAK SHORTWAVES
MOVING THROUGH THE REGION.
.LONG TERM...WEDNESDAY THROUGH MONDAY...
THE HIGHLIGHTS OF THE EXTENDED FORECAST ARE A BRIEF REPRIEVE
FROM THE HEAT FRIDAY AND SATURDAY WITH AN INCREASING TEMPERATURE
TREND THEREAFTER.
THE 31/12 UTC GUIDANCE CONSENSUS HAS SLOWED SLIGHTLY WITH THE
PROPAGATION OF THE GULF OF ALASKA ENERGY INTO THE NORTHERN PLAINS
LATE THURSDAY INTO SATURDAY. LEADING IMPULSES AHEAD OF THE MAIN WAVE
ARE EXPECTED TO PROVIDE THE LARGE SCALE SUPPORT FOR SCATTERED
THUNDERSTORMS THURSDAY EVENING ACROSS MUCH OF THE AREA...WITH
INSTABILITY AND SHEAR PROFILES ARE SUPPORTIVE OF THE POTENTIAL FOR A
FEW STRONG TO SEVERE STORMS. HIGH TEMPERATURES ON FRIDAY ARE
EXPECTED EXPECTED TO RANGE FROM THE LOWER 70S NORTHWEST TO THE MID
80S ACROSS THE JAMES RIVER VALLEY...WITH 70S AREA WIDE ON SATURDAY.
IN REGARDS TO PRECIPITATION...THE BEST CHANCES ON FRIDAY ARE
EXPECTED TO BE FOCUSED ACROSS THE SOUTH CENTRAL THROUGH THE JAMES
RIVER VALLEY ALONG THE COLD FRONT...WITH COVERAGE DECREASING
NORTHWEST WHERE PRECIPITATION WILL LIKELY BE MORE CELLULAR AND
DIURNALLY DRIVEN WITH THE COLD CORE ALOFT. A DRY SLOT IS FORECAST TO
OVERTAKE THE CWA FRIDAY NIGHT WITH WRAP AROUND PRECIPITATION
ASSOCIATED WITH THE TROWAL AT THIS TIME EXPECTED TO REMAIN NORTH OF
I-94 ON SATURDAY. THEREAFTER...MODEL UNCERTAINTY DOES INCREASE IN
REGARDS TO THE RE-AMPLIFICATION OF THE SUB TROPICAL
HIGH...HOWEVER...A WARMING TREND BACK TO AT LEAST NORMAL
TEMPERATURES ARE EXPECTED BY EARLY NEXT WEEK.
&&
.AVIATION...
THE MAIN AVIATION HAZARD WILL BE THE POTENTIAL FOR THUNDERSTORM
DEVELOPMENT LATE THIS AFTERNOON AND INTO THE EVENING ALONG A WARM
FRONT ACROSS CENTRAL NORTH DAKOTA. THE BEST TIMEFRAME FOR
THUNDERSTORM DEVELOPMENT WILL BE 22-00 UTC...POSSIBLY IN THE
VICINITY OF KBIS AND KMOT. HOWEVER...UNCERTAINTY DOES EXIST IN THE
OVERALL COVERAGE OF STORMS. STORMS WILL PUSH EAST INTO THE EVENING
TOWARDS THE KJMS TERMINAL. DUE TO UNCERTAINTY IN IMPACTS...WILL CODE
AS VCTS FOR NOW. HOWEVER...A FEW OF THESE STORMS MAY BE STRONG TO
SEVERE WITH LARGE HAIL...DAMAGING WINDS AND IFR CONDITIONS POSSIBLE.
&&
.FIRE WEATHER...
WINDS WERE SOUTHWESTERLY BEHIND THE SURFACE FRONT/TROUGH
MENTIONED ABOVE IN THE SHORT TERM SECTION. WINDS HAD BECOME WEST
AT 10 TO 20 MPH IN THE FAR WESTERN COUNTIES OF NORTH
DAKOTA...INCLUDING BEACH...BOWMAN...AND HETTINGER. TEMPERATURES
WERE IN THE 90S WITH RELATIVE HUMIDITY VALUES AROUND 25
PERCENT...AND TEMPERATURES ARE EXPECTED TO REMAIN IN THE 90S
AND/OR CLIMB TO NEAR 100. DEWPOINTS WERE IN THE LOW TO MID 50S IN
FAR WESTERN NORTH DAKOTA...BUT THINK THEY WILL DROP INTO THE 40S -
AS SITES IN EASTERN MONTANA HAVE ALREADY. THUS EXPECT RELATIVE
HUMIDITY EXPECTED TO DROP INTO THE TEENS LATE THIS AFTERNOON/EARLY
EVENING.
IT IS STILL POSSIBLE FOR THUNDERSTORM DEVELOPMENT...BUT THIS IS MORE
LIKELY ALONG THE FRONT/TROUGH WHICH HAS BEGUN TO MOVE EAST OF THE
RED FLAG AREA. ANY THUNDERSTORM THAT DEVELOPS WILL BE CAPABLE OF
PRODUCING VERY STRONG AND ERRATIC WINDS IN EXCESS OF 60 MPH.
THUS CRITICAL WEATHER BEHAVIOR REMAINS THE CONCERN FOR THE AFTERNOON
AND EARLY EVENING HOURS FOR SOUTHWEST NORTH DAKOTA AND A RED FLAG
WILL REMAIN IN EFFECT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR NDZ031-032-040-
043.
&&
$$
SHORT TERM/FIRE WEATHER...JV
LONG TERM/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
611 PM EDT TUE JUL 31 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCE THIS AFTERNOON INTO TONIGHT. COLD FRONT
MOVES THROUGH WEDNESDAY. HIGH PRESSURE WEDNESDAY NIGHT THROUGH
FRIDAY. COLD FRONT ARRIVES LATER SUNDAY AND SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
600 PM UPDATE...RAMPED UP POPS ACROSS EASTERN HIGH TERRAIN AND
POINTS NORTHWEST OF THERE...ROUGHLY ALONG AND EAST OF INTERSTATE
79. MUCH LIKE LAST EVENING...PROPAGATION OF STORMS BEING DRIVEN BY
OUTFLOW/COLD POOL INTERACTION WHICH HAS BEEN PUSHING NW OUT OF THE
HIGHER TERRAIN TOWARDS THE I-79 CORRIDOR. ALSO LOWERED POPS A BIT
ACROSS SE OHIO ZONES. EXPECT THE STRONGEST STORMS TO BEGIN WINDING
DOWN OVER THE NEXT HOUR OR TWO.
PREVIOUS DISCUSSION...
NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY DEPICTED BY RADAR
OVER NORTHERN WV MOUNTAINS...WITH MORE ISOLATED ACTIVITY SOUTHWARD
OVER THE MOUNTAINS. RAP SHOWS A VORT MAX ASSOCIATED WITH THIS
ACTIVITY...WHICH PUSHES OFF TO THE EAST THROUGH THE
AFTERNOON...WITH A SECOND VORT MAX MOVING IN FROM THE WEST. STILL
WAITING FOR SIGNS OF THE SECOND WAVE TO SHOW...AS AN OUTFLOW
BOUNDARY FROM EARLIER CONVECTION IN NORTHERN INDIANA ALSO MOVES
IN. VISIBLE SAT SHOWED SOME BUILDING CUMULUS CLOUDS IN PERRY
COUNTY...UP TOWARDS PBZ...ALONG THIS BOUNDARY BUT IT HAS BEEN
FAIRLY SLOW TO CONTINUE DEVELOPMENT. EXPECTING MORE DEVELOPMENT AS
THIS BOUNDARY PUSHES INTO CWA...WHERE THERE HAS BEEN A GOOD AMOUNT
OF HEATING SO FAR TODAY. INTERESTINGLY...THE WRFNMM SHOWS AN
OUTFLOW BOUNDARY COMING WEST OUT OF THE ACTIVITY NEAR
EKN...MEETING THE BOUNDARY APPROACHING FROM THE
NORTHEAST...DEVELOPING PRETTY ROBUST CONVECTION ALONG I-79. WILL
HAVE TO WAIT AND SEE JUST HOW THIS GOES...BUT AT ANY RATE...EXPECT
ISOLATED TO SCATTERED SHOWERS AND STORMS THIS AFTERNOON. ISOLATED
SHOWERS AND STORMS MAY LINGER OVERNIGHT...WITH SCATTERED STORMS
AGAIN WEDNESDAY AS ANOTHER UPPER LEVEL SHORTWAVE TROUGH PASSES
THROUGH.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
MODELS SHOW A BRIEF LULL IN THE ACTIVE THUNDERSTORM PATTERN AS AN
UPPER LEVEL DISTURBANCE IN NORTHWEST FLOW ALOFT EXITS TO THE
SOUTHEAST AND ALLOWS WEAK HIGH PRESSURE TO BUILD IN FOR WEDNESDAY
NIGHT AND THURSDAY. THIS WILL ALLOW DRIER AIR TO OVERSPREAD THE
AREA...THOUGH TEMPERATURES THURSDAY WILL BE SIMILAR TO WEDNESDAY.
HOWEVER...WITH THE DRIER AIR...WEDNESDAY NIGHT WILL BE SOMEWHAT
COOLER THAN PREVIOUS NIGHTS. LOOK FOR TEMPERATURES TO REACH AROUND
90 DEGREES MANY LOW LAND LOCATIONS AGAIN THURSDAY...BUT LESS
HUMIDITY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HEIGHTS ONCE AGAIN BUILD IN FROM THE WEST BY FRIDAY WITH THE BERMUDA
HIGH STRENGTHENING...ALLOWING THE HEAT AND HUMIDITY TO MOVE BACK IN
FROM THE SOUTHWEST. CHANCES FOR STORMS INCREASE LATER FRIDAY AND
SATURDAY ON MORE OF A DIURNAL BASIS WITH THE INCREASING INSTABILITY.
THIS WILL ALSO BRING MORE HEAT BACK...WITH HIGH TEMPERATURES FRIDAY
AND SATURDAY REACHING INTO THE 90S AGAIN.
ANOTHER STRONGER NORTHWEST FLOW SYSTEM AND ATTENDING COLD FRONT DROP
SOUTHEASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THIS WILL
INCREASE CHANCES FOR STORMS SUNDAY AND SUNDAY NIGHT AHEAD OF THE
FRONT. MODELS ARE SOMEWHAT DIFFERENT IN TIMING OF THE SYSTEM...BUT
SUING THE SLOWER EURO AND GFS MODELS IN THIS HIGH SUMMER PATTERN LOOKS
REASONABLE. THIS WILL PUSH THE FRONT THROUGH MONDAY MORNING WITH
SHOWERS DECREASING FROM NORTHWEST TO SOUTHEAST ON MONDAY...FOLLOWED
BY SLIGHTLY COOLER TEMPS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
CONVECTION CURRENTLY ONGOING ACROSS THE WV MOUNTAINS...ESPECIALLY
THE NORTHERN MOUNTAINS NEAR KEKN. EXPECT DROPS INTO MVFR AND EVEN
IFR IN THE HEAVIEST SHOWERS THROUGH THIS AFTERNOON...WHICH WILL NEED
TO BE ADDRESSED BY TEMPOS IF STORMS APPROACH TAF SITES. EXPECT MORE
ISOLATED TO SCATTERED CONVECTION ACROSS THE LOWLANDS...SO WILL KEEP
VCTS IN THE TAFS. EXPECT VERY WEAK WINDS TONIGHT...AND WITH CLOUDS
BECOMING SCATTERED...FOG SHOULD DEVELOP. HOWEVER WITH MORE CLOUDS
AROUND...MAY NOT SEE AS DENSE OF FOG AS LAST NIGHT AT MANY
LOCATIONS. INCLUDED MVFR VISIBILITIES AT KCRW...KHTS...KPKB...WITH
DENSE LIFR FOG AT KEKN...AND IN OTHER PRONE VALLEY LOCATIONS. WILL
AGAIN SEE SCATTERED SHOWERS AND THUNDERSTORMS ON
WEDNESDAY...ESPECIALLY FROM CRW-CKB AND WESTWARD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF THUNDERSTORMS COULD VARY THROUGH THE
PERIOD. TIMING AND DENSITY OF FOG DISSIPATION COULD VARY TONIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03
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 L L L
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 00Z THURSDAY...
BRIEF IFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/MZ
NEAR TERM...MZ/50
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
417 PM EDT TUE JUL 31 2012
.SYNOPSIS...
A WEAK COLD FRONT MAY BRING A FEW THUNDERSTORMS THIS EVENING.
HIGH PRESSURE WILL ALLOW FOR DRY CONDITIONS WEDNESDAY AND
THURSDAY. SHORT WAVE ENERGY ABOVE AN UNSTABLE AIRMASS WILL PROVIDE
A CHANCE OF THUNDERSTORMS ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A TROUGH IN THE UPPER ATMOSPHERE IS EVIDENT ON WATER VAPOR IMAGERY
AND ON MODELS. SURFACE MAP HAS A WEAK TROUGH OVER NORTHWEST OHIO
WITH HIGHER DEW POINTS AND GREATER INSTABILITY BEHIND THE TROUGH.
ISOLATED THUNDERSTORMS HAVE DEVELOPED ALONG AND BEHIND THE TROUGH
AXIS...ESPECIALLY OVER WESTERN INDIANA AND EASTERN ILLINOIS WHERE
A SEVERE THUNDERSTORM WATCH IS IN EFFECT.
AS THE SURFACE TROUGH MOVES EAST THIS EVENING...INSTABILITY WILL
INCREASE AND SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP. WITH
WITH DELTA THETA E VALUES OF ~30K...STRONG DOWNDRAFT POTENTIAL
EXISTS SO SOME THUNDERSTORMS MAY BE SEVERE...ESPECIALLY OVER
SOUTHWEST COUNTIES WHERE SHEAR AND INSTABILITY WILL BE SLIGHTLY
MORE FAVORABLE.
THUNDERSTORMS SHOULD WIND DOWN OVERNIGHT WITH LOSS OF DAYTIME
HEATING. UNDER MOSTLY CLEAR SKIES BY DAYBREAK...TEMPERATURES WILL
FALL TO THE MID AND UPPER 60S.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
TROUGH AXIS WILL BE MOVING EAST OF THE AREA AND DRIER AND MORE
STABLE AIR WILL BE MOVING IN WITH HIGH PRESSURE. THE AREA SHOULD
BE FREE FROM PRECIPITATION SINCE CONVECTION ASSOCIATED WITH THE
TROUGH WILL PROBABLY NOT FIRE UP UNTIL THE TROUGH EXITS IN THE
AFTERNOON. CLEAR SKIES ARE EXPECTED WEDNESDAY NIGHT WITH HIGH
PRESSURE CENTERED OVER NORTHERN OHIO.
TEMPERATURES WILL BE CLOSE TO NORMAL AND A BIT COOLER WITH HIGHS
IN THE MID AND UPPER 80S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE ON THURSDAY WILL BE FOUND WITH ZONAL FLOW ALOFT. THERE
WAS SOME EARLIER NOTES OF VORT MAXES AND/OR WEAK SHORTWAVES IN THIS
FLOW WHICH MAY INSTIGATE SOME SHOWER ACTIVITY ON FRIDAY...BUT KEPT
LOWERING CHANCES SIGNIFICANTLY FROM PREVIOUS FORECAST. RETURN FLOW
AT THE SURFACE WILL ALLOW TEMPERATURES TO INCREASE AND MOISTURE TO
STREAM IN FROM THE SOUTH FOR FRIDAY. LOW PRESSURE WELL TO THE
NORTHWEST COULD PUSH ENOUGH MOISTURE AND INSTABILITY INTO THE OHIO
VALLEY IN THE WARM SECTOR THAT SCATTERED POPUP SHOWERS ARE POSSIBLE
ON SATURDAY TRIGGERED BY DAYTIME HEATING.
THE COLD FRONT IS PROGGED TO CROSS THE OHIO VALLEY ON SUNDAY AND
THIS IS THE DAY WHERE SHOWERS AND THUNDERSTORMS WILL BE AT THEIR
PROBABILISTIC PEAK. BEING 5 DAYS OUT I WAS HESITANT TO GO WITH
LIKELY WORDING AS THERE WILL BE TIMING ISSUES TO WORK OUT.
AFTER THE FRONT CROSSES...ANY LINGERING SHOWERS SUNDAY NIGHT SHOULD
END FROM NORTHWEST TO SOUTHEAST AND HIGH PRESSURE WILL HELP PUSH IN
DRIER AND COOLER AIR IN ITS WAKE FOR EARLY NEXT WEEK. TEMPERATURES
WILL MODERATE QUICKLY AS AN APPARENT LACK OF CLOUD COVER WILL
PROBABLY ALLOW ABUNDANT SUNSHINE TO WARM THE REGION BACK UP. EVEN
WITH THE WARMER TEMPERATURES EXPECTED TO RETURN...DRIER AIR SHOULD
LET NIGHTTIME LOWS DROP NICELY.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS TO CONTINUE TODAY. REMNANTS OF EARLY MORNING
MCS HAS LEFT A CAP OVER ILN/S CWA...EVIDENT IN LATEST RAP DATA AND
CU FREE VISIBLE IMAGERY. HAVE MOVED BACK MENTION OF THUNDER TIMING
AND LIMITED THIS MENTION TO VCTS TO BETWEEN 21Z AND 02Z. FORCING
IS RATHER WEAK SO UNCERTAINTY IN LOCATION AND TIMING CONTINUES TO
BE LOW. CLOUD BASES WILL BE HIGH BASED AND VFR IN ANY STORMS THAT
DUE OCCUR AT THE TAF SITES. AS SKIES CLEAR AND WINDS BECOME LIGHT
OVERNIGHT...EXPECT VISIBILITY RESTRICTIONS TO DEVELOP IN MIST/FOG.
.OUTLOOK...MVFR VISIBILITIES POSSIBLE WEDNESDAY NIGHT INTO EARLY
THURSDAY. THUNDERSTORMS POSSIBLE FRIDAY INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...FRANKS
AVIATION...AR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
246 PM EDT TUE JUL 31 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCE THIS AFTERNOON INTO TONIGHT. COLD FRONT
MOVES THROUGH WEDNESDAY. HIGH PRESSURE WEDNESDAY NIGHT THROUGH
FRIDAY. COLD FRONT ARRIVES LATER SUNDAY AND SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY DEPICTED BY RADAR OVER
NORTHERN WV MOUNTAINS...WITH MORE ISOLATED ACTIVITY SOUTHWARD OVER
THE MOUNTAINS. RAP SHOWS A VORT MAX ASSOCIATED WITH THIS
ACTIVITY...WHICH PUSHES OFF TO THE EAST THROUGH THE AFTERNOON...WITH
A SECOND VORT MAX MOVING IN FROM THE WEST. STILL WAITING FOR SIGNS
OF THE SECOND WAVE TO SHOW...AS AN OUTFLOW BOUNDARY FROM EARLIER
CONVECTION IN NORTHERN INDIANA ALSO MOVES IN. VISIBLE SAT SHOWED
SOME BUILDING CUMULUS CLOUDS IN PERRY COUNTY...UP TOWARDS
PBZ...ALONG THIS BOUNDARY BUT IT HAS BEEN FAIRLY SLOW TO CONTINUE
DEVELOPMENT. EXPECTING MORE DEVELOPMENT AS THIS BOUNDARY PUSHES
INTO CWA...WHERE THERE HAS BEEN A GOOD AMOUNT OF HEATING SO FAR
TODAY. INTERESTINGLY...THE WRFNMM SHOWS AN OUTFLOW BOUNDARY COMING
WEST OUT OF THE ACTIVITY NEAR EKN...MEETING THE BOUNDARY APPROACHING
FROM THE NORTHEAST...DEVELOPING PRETTY ROBUST CONVECTION ALONG I-79.
WILL HAVE TO WAIT AND SEE JUST HOW THIS GOES...BUT AT ANY
RATE...EXPECT ISOLATED TO SCATTERED SHOWERS AND STORMS THIS
AFTERNOON. ISOLATED SHOWERS AND STORMS MAY LINGER OVERNIGHT...WITH
SCATTERED STORMS AGAIN WEDNESDAY AS ANOTHER UPPER LEVEL SHORTWAVE
TROUGH PASSES THROUGH.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
MODELS SHOW A BRIEF LULL IN THE ACTIVE THUNDERSTORM PATTERN AS AN
UPPER LEVEL DISTURBANCE IN NORTHWEST FLOW ALOFT EXITS TO THE
SOUTHEAST AND ALLOWS WEAK HIGH PRESSURE TO BUILD IN FOR WEDNESDAY
NIGHT AND THURSDAY. THIS WILL ALLOW DRIER AIR TO OVERSPREAD THE
AREA...THOUGH TEMPERATURES THURSDAY WILL BE SIMILAR TO WEDNESDAY.
HOWEVER...WITH THE DRIER AIR...WEDNESDAY NIGHT WILL BE SOMEWHAT
COOLER THAN PREVIOUS NIGHTS. LOOK FOR TEMPERATURES TO REACH AROUND
90 DEGREES MANY LOW LAND LOCATIONS AGAIN THURSDAY...BUT LESS
HUMIDITY.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
HEIGHTS ONCE AGAIN BUILD IN FROM THE WEST BY FRIDAY WITH THE BERMUDA
HIGH STRENGTHENING...ALLOWING THE HEAT AND HUMIDITY TO MOVE BACK IN
FROM THE SOUTHWEST. CHANCES FOR STORMS INCREASE LATER FRIDAY AND
SATURDAY ON MORE OF A DIURNAL BASIS WITH THE INCREASING INSTABILITY.
THIS WILL ALSO BRING MORE HEAT BACK...WITH HIGH TEMPERATURES FRIDAY
AND SATURDAY REACHING INTO THE 90S AGAIN.
ANOTHER STRONGER NORTHWEST FLOW SYSTEM AND ATTENDING COLD FRONT DROP
SOUTHEASTWARD TOWARD THE AREA SUNDAY AND SUNDAY NIGHT. THIS WILL
INCREASE CHANCES FOR STORMS SUNDAY AND SUNDAY NIGHT AHEAD OF THE
FRONT. MODELS ARE SOMEWHAT DIFFERENT IN TIMING OF THE SYSTEM...BUT
SUING THE SLOWER EURO AND GFS MODELS IN THIS HIGH SUMMER PATTERN LOOKS
REASONABLE. THIS WILL PUSH THE FRONT THROUGH MONDAY MORNING WITH
SHOWERS DECREASING FROM NORTHWEST TO SOUTHEAST ON MONDAY...FOLLOWED
BY SLIGHTLY COOLER TEMPS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
CONVECTION CURRENTLY ONGOING ACROSS THE WV MOUNTAINS...ESPECIALLY
THE NORTHERN MOUNTAINS NEAR KEKN. EXPECT DROPS INTO MVFR AND EVEN
IFR IN THE HEAVIEST SHOWERS THROUGH THIS AFTERNOON...WHICH WILL NEED
TO BE ADDRESSED BY TEMPOS IF STORMS APPROACH TAF SITES. EXPECT MORE
ISOLATED TO SCATTERED CONVECTION ACROSS THE LOWLANDS...SO WILL KEEP
VCTS IN THE TAFS. EXPECT VERY WEAK WINDS TONIGHT...AND WITH CLOUDS
BECOMING SCATTERED...FOG SHOULD DEVELOP. HOWEVER WITH MORE CLOUDS
AROUND...MAY NOT SEE AS DENSE OF FOG AS LAST NIGHT AT MANY
LOCATIONS. INCLUDED MVFR VISIBILITIES AT KCRW...KHTS...KPKB...WITH
DENSE LIFR FOG AT KEKN...AND IN OTHER PRONE VALLEY LOCATIONS. WILL
AGAIN SEE SCATTERED SHOWERS AND THUNDERSTORMS ON
WEDNESDAY...ESPECIALLY FROM CRW-CKB AND WESTWARD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF THUNDERSTORMS COULD VARY THROUGH THE
PERIOD. TIMING AND DENSITY OF FOG DISSIPATION COULD VARY TONIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z WEDNESDAY...
BRIEF IFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/MZ
NEAR TERM...MZ
SHORT TERM...JMV
LONG TERM...JMV
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
230 PM EDT TUE JUL 31 2012
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE AREA TODAY
AS A COLD FRONT APPROACHES AND MOVES THROUGH THE REGION. HIGH
PRESSURE WILL ALLOW FOR DRY CONDITIONS WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY MORNING MCS WHICH DROPPED SE ACRS NRN IN AND INTO NW OHIO
HAS WEAKENED...LEAVING AN OUTFLOW BOUNDARY WHICH IS DROPPING INTO
SRN IN AND SRN OHIO. MID LEVEL S/W TO TRACK THRU THE EASTERN GREAT
LAKES TODAY WITH A TAIL OF VORTICITY DROPPING THRU SRN OHIO EARLY
THIS EVENING. ASSOCIATED SLOW MOVING COLD FRONT TO SLIP INTO OHIO
OVERNIGHT.
WITH SFC HEATING AND SOME ADVECTION OF LOW LEVEL MOISTURE FROM
THE W WILL RESULT IN MODERATE INSTABILITY. THUNDERSTORM DEVELOPMENT
WILL BE LKLY AHD THE OUTFLOW BOUNDARY...AS WELL AS IN ADVANCE OF
THE COLD FRONT BY MID AFTERNOON ALONG THESE BOUNDARIES. A FEW
STORMS COULD PRODUCE DAMAGING WINDS AND MARGINALLY SEVERE HAIL
THIS AFTERNOON INTO EARLY EVENING ACRS SE INDIANA/SW OH AND NRN
KY. WILL HIGHLIGHT THIS POTENTIAL IN THE HWO PRODUCT.
HAVE CONTD PREV FCST THINKING GOING ON THE WARM SIDE OF TEMP GUIDANCE
FOR HIGH TEMPERATURES TODAY. HEAT INDEX VALUES WILL BE IN THE
MIDDLE TO UPPER 90S ACRS THE SW AND WILL CONTINUE TO HIGHLIGHT
THESE VALUES IN THE HWO FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
SHOWER AND THUNDERSTORM ACTIVITY WILL BEGIN TO TAPER OFF ACROSS
THE FA THIS EVENING AND DRY CONDITIONS WILL RETURN TO THE FA BY
AROUND MIDNIGHT TONIGHT. HIGH PRESSURE WILL WORK INTO THE FA FOR
WEDNESDAY AND THURSDAY ALLOWING FOR DRY CONDITIONS ACROSS THE
REGION. THE MODELS CONTINUE TO DISAGREE ON THE AMOUNT OF MOISTURE
WORKING NORTH INTO THE AREA ON FRIDAY INTO FRIDAY NIGHT. DUE TO
RUN TO RUN INCONSISTENCIES AND MODEL DIFFERENCES DECIDED TO GO WITH
A BLEND FOR FRIDAY AND FRIDAY NIGHT. IN ADDITION...DUE TO
UNCERTAINTIES IN THE PLACEMENT AND TIMING OF THE PRECIPITATION
HAVE DECIDED TO LIMIT PRECIPITATION CHANCES TO THE CHANCE CATEGORY
AT THIS TIME. WENT CLOSE TO GUIDANCE FOR TEMPERATURES DURING THE
SHORT TERM TIME FRAME.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HAVE TAKEN A BLEND OF NCEP/HPC AND THE 00Z ECMWF/12Z GFS FOR THE
EXTENDED FORECAST.
UPR LVL FLOW WILL TRANSITION TO A MORE ZONAL PATTERN ON SATURDAY...AND
WITH RETURN SFC FLOW/MOISTURE AND EMBEDDED DISTURBANCES RIPPLING
WEST TO EAST ALOFT...HAVE KEPT CHANCES FOR SHOWERS/STORMS DURING
THIS PERIOD. IT MUST BE NOTED THAT THE ECMWF CONTINUES TO SHOW A
MORE DEEPER MOISTURE TRANSPORT INTO THE REGION ON SATURDAY WHILE
THE GFS AND CMC SHOW A MORE DISJOINTED MOISTURE RETURN FLOW. THE
RESULT IS HIGHER CHANCES FOR PCPN ON THE ECMWF AND MUCH LOWER
CHANCES ON THE GFS AND CMC. THIS HAS YET TO BE RESOLVED AND HAVE
THUS KEPT CHANCE POPS. A STRONGER S/WV AND COLD FRONT IS POISED TO
AFFECT THE REGION SUNDAY AND SUNDAY NIGHT...OFFERING AN ENHANCED
CHANCE OF SHOWERS AND STORMS. THE COLD FRONT IS PROGGED TO SLIDE
SE OF THE AREA ON MONDAY...GRADUALLY BRINGING AN END TO THE PCPN
AND ALLOWING DRIER AIR TO BUILD BACK INTO THE AREA ONCE AGAIN.
TEMPERATURES ON A WHOLE SHOULD AVERAGE ABOVE NORMAL THROUGH THE
PERIOD. HOW FAR ABOVE NORMAL WILL DEPEND ON CLOUD COVER AND
PRECIPITATION COVERAGE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
EXPECT VFR CONDITIONS TO CONTINUE TODAY. REMNANTS OF EARLY MORNING
MCS HAS LEFT A CAP OVER ILN/S CWA...EVIDENT IN LATEST RAP DATA AND
CU FREE VISIBLE IMAGERY. HAVE MOVED BACK MENTION OF THUNDER TIMING
AND LIMITED THIS MENTION TO VCTS TO BETWEEN 21Z AND 02Z. FORCING
IS RATHER WEAK SO UNCERTAINTY IN LOCATION AND TIMING CONTINUES TO
BE LOW. CLOUD BASES WILL BE HIGH BASED AND VFR IN ANY STORMS THAT
DUE OCCUR AT THE TAF SITES. AS SKIES CLEAR AND WINDS BECOME LIGHT
OVERNIGHT...EXPECT VISIBILITY RESTRICTIONS TO DEVELOP IN MIST/FOG.
.OUTLOOK...MVFR VISIBILITIES POSSIBLE WEDNESDAY NIGHT INTO EARLY
THURSDAY. THUNDERSTORMS POSSIBLE FRIDAY INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...AR
SHORT TERM...NOVAK
LONG TERM...HICKMAN
AVIATION...AR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
130 PM EDT TUE JUL 31 2012
.SYNOPSIS...
UPPER LEVEL DISTURBANCE THIS AFTERNOON INTO TONIGHT. COLD FRONT
MOVES THROUGH WEDNESDAY. HIGH PRESSURE WEDNESDAY NIGHT THROUGH
FRIDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
NUMEROUS SHOWERS AND THUNDERSTORMS CURRENTLY DEPICTED BY RADAR OVER
NORTHERN WV MOUNTAINS...WITH MORE ISOLATED ACTIVITY SOUTHWARD OVER
THE MOUNTAINS. RAP SHOWS A VORT MAX ASSOCIATED WITH THIS
ACTIVITY...WHICH PUSHES OFF TO THE EAST THROUGH THE AFTERNOON...WITH
A SECOND VORT MAX MOVING IN FROM THE WEST. STILL WAITING FOR SIGNS
OF THE SECOND WAVE TO SHOW...AS AN OUTFLOW BOUNDARY FROM EARLIER
CONVECTION IN NORTHERN INDIANA ALSO MOVES IN. VISIBLE SAT SHOWED
SOME BUILDING CUMULUS CLOUDS IN PERRY COUNTY...UP TOWARDS
PBZ...ALONG THIS BOUNDARY BUT IT HAS BEEN FAIRLY SLOW TO CONTINUE
DEVELOPMENT. EXPECTING MORE DEVELOPMENT AS THIS BOUNDARY PUSHES
INTO CWA...WHERE THERE HAS BEEN A GOOD AMOUNT OF HEATING SO FAR
TODAY. INTERESTINGLY...THE WRFNMM SHOWS AN OUTFLOW BOUNDARY COMING
WEST OUT OF THE ACTIVITY NEAR EKN...MEETING THE BOUNDARY APPROACHING
FROM THE NORTHEAST...DEVELOPING PRETTY ROBUST CONVECTION ALONG I-79.
WILL HAVE TO WAIT AND SEE JUST HOW THIS GOES...BUT AT ANY
RATE...EXPECT ISOLATED TO SCATTERED SHOWERS AND STORMS THIS
AFTERNOON. ISOLATED SHOWERS AND STORMS MAY LINGER OVERNIGHT...WITH
SCATTERED STORMS AGAIN WEDNESDAY AS ANOTHER UPPER LEVEL SHORTWAVE
TROUGH PASSES THROUGH.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AREA WILL CONT TO BE UNDER THE INFLUENCE OF UPR TROF WITH NW FLOW IN
THE MID AND UPR LEVELS. LAGGING SFC FRONT TAKES ALL OF WED TO
ATTEMPT TO CROSS CWA MORE LKLY WASHING OUT OVER UPR OH VALLEY
LEAVING BEHIND AREA OF WEAK LLVL CONVERGENCE/TROF NEARBY. KEPT POPS
LOW WITH THIS AS OVERALL MOISTURE DEPTH IS LACKING. HAVING SAID THAT
STILL EXPECT A FEW SHRA/TSRA WITH THE BOUNDARY. SFC HIGH BUILDS IN
FOR THU WITH ONLY SLIGHTLY LOWER HUMIDITY BUT REMAINING RATHER WARM.
AN UPR LVL DISTURBANCE MAY DROP DOWN WITHIN UPR TROF FRIDAY WITH
SOME STORMS TO ACCOMPANY IT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
HEIGHTS ONCE AGAIN BUILD IN FROM THE WEST FRIDAY WITH THE BERMUDA
HIGH STRENGTHENING...ALLOWING THE HEAT AND HUMIDITY TO MOVE BACK IN
FROM THE SOUTHWEST. CHANCES FOR STORMS INCREASE BY THE WEEKEND AS
ANOTHER NORTHWEST FLOW SYSTEM AND ATTENDING COLD FRONT DROP
SOUTHEASTWARD TOWARD THE AREA. TEMPS WILL ALSO WARM BACK INTO THE
90S AHEAD OF THE FRONT.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
CONVECTION CURRENTLY ONGOING ACROSS THE WV MOUNTAINS...ESPECIALLY
THE NORTHERN MOUNTAINS NEAR KEKN. EXPECT DROPS INTO MVFR AND EVEN
IFR IN THE HEAVIEST SHOWERS THROUGH THIS AFTERNOON...WHICH WILL NEED
TO BE ADDRESSED BY TEMPOS IF STORMS APPROACH TAF SITES. EXPECT MORE
ISOLATED TO SCATTERED CONVECTION ACROSS THE LOWLANDS...SO WILL KEEP
VCTS IN THE TAFS. EXPECT VERY WEAK WINDS TONIGHT...AND WITH CLOUDS
BECOMING SCATTERED...FOG SHOULD DEVELOP. HOWEVER WITH MORE CLOUDS
AROUND...MAY NOT SEE AS DENSE OF FOG AS LAST NIGHT AT MANY
LOCATIONS. INCLUDED MVFR VISIBILITIES AT KCRW...KHTS...KPKB...WITH
DENSE LIFR FOG AT KEKN...AND IN OTHER PRONE VALLEY LOCATIONS. WILL
AGAIN SEE SCATTERED SHOWERS AND THUNDERSTORMS ON
WEDNESDAY...ESPECIALLY FROM CRW-CKB AND WESTWARD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF THUNDERSTORMS COULD VARY THROUGH THE
PERIOD. TIMING AND DENSITY OF FOG DISSIPATION COULD VARY TONIGHT.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY 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 18Z WEDNESDAY...
BRIEF IFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JMV/MZ
NEAR TERM...MZ
SHORT TERM...30
LONG TERM...JMV
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1257 PM EDT TUE JUL 31 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL KEEP THE AREA IN A FAVORED PATTERN FOR
SCATTERED SHOWERS AND STORMS INTO WEDNESDAY. A FRONT WILL APPROACH
THE AREA WEDNESDAY BEFORE DISSIPATING. FOR LATE WEEK...THE HEAT
RIDGE STARTS TO BE MORE OF INFLUENCE INTO OUR AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 925 AM EDT TUESDAY...
ALREADY SEEING SHRA/TSRA DEVELOP OVER THE FAR WEST IN THE WEAK
CONVERGENCE ZONE/85H THETA-E RIDGE NORTH OF THE MCS PASSING ACROSS
THE SE STATES. EXPECT WITH CONTINUED HEATING WILL SEE CONVECTION
ORGANIZE MORE OVER THE SW AND GRADUALLY UNZIP TO THE NE ESPCLY
OVER THE MOUNTAINS AS THE NEXT PIECE OF UPPER TROFFINESS SLIDES
EAST. JUST HOW MUCH INTERACTION BETWEEN THE TWO OCCURS WILL
DETERMINE COVERAGE/STRENGTH OF STORMS GIVEN LOWER WET BULBS BUT
SLIGHTLY BETTER FLOW ALOFT THIS AFTERNOON. THINK NEXT SHORTWAVE
AND ASSOCIATED OUTFLOW TO THE NW PER VIS PICS SHOULD KEEP MOST OF
THAT COVERAGE TO THE WEST UNTIL LATE SO MAINLY LOOKING AT
SCATTERED MULTICELLULAR ACTION MAINLY MOUNTAINS WITH RENEWED
COVERAGE DRIVEN BY OUTFLOW. CURRENT FOG/STABILITY OUT EAST WILL
LIKELY LIMIT DEVELOPMENT EAST OF THE BLUE RIDGE AS COVERAGE THERE
LOOKS TO COME FROM CELLS HEATING OFF THE BLUE RIDGE LATER ON.
LATEST HRRR LOOKS TO SUPPORT THIS SCENARIO SO UPPED POPS TO LOW
LIKELYS IN A STRIP OUT EAST AND TRENDED DOWN TO JUST LOW CHANCE SE
PIEDMONT. STRONGER CELLS SHOULD AGAIN BE ABLE TO TAP SOME DRY AIR
ALOFT AND WITH COOLER AIR ALOFT UNDER THE TROF AXIS LIKELY MORE OF
A HAIL THREAT AS WELL SO KEEPING HWO MENTION. KEPT HIGHS CLOSER TO
THE COOLER MET MOS GIVEN CLOUDS/SHRA WEST IN SPOTS AND WIDESPREAD
STRATUS/FOG EAST TO INIT BUT STILL EXPECTING MOST IN THE 80S BY
LATE IN THE DAY.
AS OF 725 AM EDT TUESDAY...
TWO SHORTWAVES THIS MORNING CAUSING SHOWERS/TSRA OUTSIDE OUR
FORECAST AREA. MAIN ONE IS SOUTHWEST OF US IN THE TN VALLEY
CREATING SHRA/TSRA A COUPLE OF COUNTIES SOUTH OF WATAUGA...WITH
ANOTHER WEAK WAVE INDUCING SHOWERS IN WEBSTER COUNTY WV.
THE THREAT OF SHOWERS/STORMS INCREASES AROUND LATE MORNING...WITH
BEST THREAT IN THE MTNS...WITH ISOLATED COVERAGE IN THE PIEDMONT.
PREVIOUS DISCUSSION...
VERY LITTLE ON RADAR THIS MORNING WITH ONE LONE SHOWER UP NORTH OF
CHARLOTTESVILLE VA...WITH GENERALLY PC SKIES ACROSS THE FORECAST
AREA. MAIN AXIS OF PRECIP AND UPPER LEVEL ENERGY RESIDES ACROSS SRN
KY INTO TN THIS MORNING AND THIS SHORTWAVE IS ANTICIPATED TO SLIDE
SOUTHEAST TOWARD GA/SC LATER THIS MORNING. MODELS SHOWING SOME
AGREEMENT IN KEEPING THE BEST THREAT OF PRECIP ACROSS THE MTNS
TODAY...WITH BEST SUPPORT IN THE NC MTNS. HAVE GONE WITH 40/50 POPS
IN THE MTNS WITH 30 OUT EAST...BUT LOOKING AT LATEST LOCAL WRF
TRENDS AND WV LOOP LEADS ME TO THINK THAT COVERAGE ESPECIALLY EAST
OF THE BLUE RIDGE TODAY MAY BE ISOLATED. WENT A LITTLE CLOUDIER
TODAY IN THE MTNS...AND LEANED TOWARD THE COOLER MET/LOCAL MOS
NUMBERS HERE WITH LOWER-MID 80S FOR HIGHS AND EVEN 70S ACROSS THE NC
MTNS PER BETTER CONVECTION THREAT. THE EAST SHOULD REACH THE UPPER
80S.
TONIGHT...THE CONVECTION SHOULD WANE ACROSS THE AREA WITH DEPARTING
SHORTWAVE BUT WILL HAVE TO KEEP AN EYE ON THE CURRENT MCS AND
ASSOCIATED VORT/COLD FRONT MOVING ACROSS MICHIGAN AND SRN WISCONSIN THIS
MORNING. THE ECMWF/NAM TRACK THIS SYSTEM SOUTHEAST INTO THE WV MTNS
AFTER MIDNIGHT TONIGHT BUT THEN DISSIPATE IT. I AM INCLINED TO HAVE
AT LEAST CHANCE POPS IN THE WEST VIRGINIA/VA HIGHLANDS AREA WITH
SLIGHT CHANCE TO THE SOUTHEAST OF THIS AREA OVERNIGHT...THEN
TAPER IT OFF AROUND DAWN WED. KEPT LOWS IN THE 60S AREAWIDE
SIMILAR TO MOS NUMBERS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
AS OF 255 AM EDT TUESDAY...
WEDNESDAY INTO WEDNESDAY NIGHT...A GENERAL PATTERN OF TROUGHINESS IN
THE EAST CONTINUES...WHILE AN UPPER RIDGE REMAINS PARKED OVER MUCH
OF THE TEXAS AND FOUR CORNERS REGION. A COLD FRONT ASSOCIATED WITH
THE EAST COAST TROUGH WILL SWING THROUGH THE AREA ON WEDNESDAY
BRINGING SCATTERED SHOWERS AND STORMS. THE LATEST DAY 2 CONVECTIVE
OUTLOOK FROM THE STORM PREDICTION CENTER SUGGESTS LAPSE RATES MAY
BE STEEP ENOUGH FOR SOME LOCALIZED ENHANCED CONVECTION THAT YIELDS
SEVERE WINDS AND HAIL. TEMPERATURES WILL TREND A BIT WARMER AS
COMPARED TO TUESDAY IN ADVANCE OF THE APPROACHING COLD FRONT.
DAYTIME CONVECTION WILL CONTINUE INTO THE EVENING HOURS WITH
ISOLATED SHOWERS AND STORMS CONTINUING ACROSS SOUTHERN AND EASTERN
PARTS OF THE AREA NEAREST THE EXITING COLD FRONT. ANTICIPATE
PRECIPITATION TO END BY MIDNIGHT WITH DECREASING CLOUD COVER. FOG
DEVELOPMENT WILL BE LIKELY DURING THE EARLY MORNING HOURS OF
THURSDAY...ESPECIALLY ACROSS THE MOUNTAINS VALLEYS AND THE RIVER
VALLEYS OF THE PIEDMONT.
THURSDAY INTO FRIDAY...THE EAST COAST TROUGH WILL FLATTEN A BIT AS
THE UPPER RIDGE SHIFTS EAST INTO THE LOWER MISSISSIPPI VALLEY.
ANTICIPATE A TREND TOWARD HOTTER TEMPERATURES. OTHER THAN SOME
ISOLATED SHOWERS AND STORMS IN THE NORTHERN MOUNTAINS OF NORTH
CAROLINA...DRY CONDITIONS ARE EXPECTED ON THURSDAY. BY FRIDAY...A
RETURN FLOW IS EXPECTED AS THE CENTER OF SURFACE HIGH PRESSURE
SHIFTS EAST A SHORTWAVE TROUGH MOVES EASTWARD WITHIN A ZONAL FLOW
THROUGH THE OHIO VALLEY. LOOK FOR THE DEVELOPMENT OF ISOLATED TO
SCATTERED SHOWERS AND STORMS ONCE AGAIN.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 230 PM EDT MONDAY...
WITH MORE PERSISTENT SOUTHERLY FLOW DEVELOPING INTO THE
WEEKEND...DEWPOINTS WILL BE ON THE RISE AND SO WILL INSTABILITY AS
RH INCREASES AT H7 AND H5. SHOWERS AND STORMS WILL BE MORE NUMEROUS
ON SUNDAY IN COMPARISON TO SATURDAY. ALTHOUGH H85 TEMPS MAY RISE A
FEW MORE DEGREES...MAX T WILL BE STUNTED BY MORE CLOUDS AND
THUNDERSTORMS. A COLD FRONT DROPS OUT OF THE GREAT LAKES EARLY NEXT
WEEK...SUCH THAT SHOWERS AND STORMS WILL BE MOST LIKELY ON MONDAY
AND MONDAY NIGHT. HIGH TEMPS SHOULD BE IN THE MIDDLE 80S TO LOWER
90S THROUGH THE PERIOD.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 1235 PM EDT TUESDAY...
LOW CIGS CONTINUE TO SLOWLY IMPROVE TO VFR ESPCLY ALONG AND EAST
OF THE BLUE RIDGE WHERE FOG/STRATUS HAVE BEEN STUCK FOR MUCH OF
THE MORNING. EXPECT THIS TREND TO PREVAIL INTO THE AFTERNOON WITH
MAINLY 4-6K FT CU FIELDS FOR MOST SPOTS UNTIL LOSS OF HEATING.
THE MAIN THREAT OF SLOW MOVING MULTICELLULAR STORMS CONTINUES IN
THE WESTERN LOCATIONS ALONG AND SOUTH OF A LINE FROM KLWB-KBCB
THIS AFTERNOON. OVERALL...COVERAGE WILL BE SCATTERED ELSEWHERE BUT
CONFIDENCE IS HIGH THAT SHOWERS AND STORMS WILL BE IN THE VICINITY
OF ALL MOST TAF SITES IN THE AFTN SO KEPT IT IN.
SHOULD SEE A QUICK WEAKENING TREND TO CONVECTION THIS EVENING AS
THE SHORTWAVE PASSES. HOWEVER...ANOTHER SHORTWAVE UPSTREAM MAY
BRING SHOWERS INTO THE KLWB/KBLF AREA THROUGH LATE THIS EVENING.
CIGS MAY DROP AGAIN LATE TUE NIGHT AS WELL AS VSBYS DEPENDING ON
EXTENT OF RAINFALL...AND CLEARING SKIES SO LOWERED CIGS/VSBYS TO
IFR/MVFR MOST SPOTS EXCLUDING KROA BUT NOT AS LOW AS LAST NIGHT.
THE DAILY AFTERNOON AND EVENING THREAT OF SHOWERS AND
THUNDERSTORMS CONTINUES THROUGH THE WEEK BUT SHOULD BECOME MORE
WIDELY SCATTERED WEDNESDAY...AND ISOLATED THURSDAY INTO FRIDAY AS
WEAK HIGH PRESSURE SETTLES IN FROM THE WEST. MOISTURE WILL BEGIN
TO RETURN OVER THE WEEKEND WITH DIURNAL BOUTS OF SHOWERS AND
STORMS LIKELY WITH MOSTLY AFTERNOON/EVENING MVFR CONDITIONS
POSSIBLE AT TIMES SATURDAY AND SUNDAY. OUTSIDE OF THIS MAINLY
DIURNALLY DRIVEN CONVECTION...THE ONLY OTHER FLIGHT WEATHER
HAZARDS WOULD BE FROM OVERNIGHT VALLEY FOG.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...JC
LONG TERM...KM
AVIATION...AMS/JH/WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
242 PM PDT Tue Jul 31 2012
.SYNOPSIS...
An upper level low currently over the gulf of Alaska will drop
southwest over the next couple days resulting in only a small
chance of thunderstorms near the Canadian border. Drier northwest
flow will spill into the region Thursday evening and continue
through Saturday resulting in dry but locally breezy weather.
Warmer and increasingly unsettled conditions could return to the
region by Sunday and continuing into early next week.
&&
.DISCUSSION...
Tonight...Weak upper level shortwave trough continues to cross
Washington this evening and should move into north Idaho around
sunset. The big question is will this disturbance be able to
trigger a thunderstorm or two. The latest instability numbers from
the RUC and LAPS are not terribly impressive...however small
pockets of CAPEs around 500 j/kg are located near the Canadian
border. The convective caps have been weakening...however up
through now...only small cumulus fields have been forming over the
higher terrain near the US/Canadian border. We will keep a slight
chance of thunder mentioned through early evening near the
international border but the remainder of the forecast area will
be left dry for the night. fx
Wednesday through Friday: Following a quiet, seasonal weather
day on Wednesday, our focus will switch gears toward an upper-
level trough swinging across southern BC...northeastern WA...and
northern ID for Thursday/Thursday night. The midlevel wave will
usher a strong cold front through the region resulting in a
passing shield of clouds, chance for light showers across the
northeastern zones, breezy northerly winds, and a slight chance
for post-frontal convection and perhaps an isolated thunderstorm.
Dry, northerly flow behind Thursday`s shortwave will promote
another day of mostly clear skies and seasonal temperatures.
Overall, models are in general agreement through the period and
confidence is near to above normal.
The center of the upper-low driving the cold front will track
S/SE down the BC/Alberta. The tail, or southwestern flank of the
strongest synoptic forcing will cross NE WA and N ID Thursday
afternoon. There is a modest moisture fetch that becomes entrained
into the system with precipitable waters of an inch or higher
along the coast...decreasing near 0.80" over N Idaho. Forcing
along the cold front in conjunction with large-scale ascent
associated with differential PVA will lead to a layer saturation
and band of thick clouds passing with the initial 700-500mb cold
front. Light showers will be possible within this band but the
threat for thunderstorms will be low. As the 500mb cold pool
slides over the northeastern zones in the post-frontal air mass
Thursday afternoon... there is a chance for convection to fire
with forecast soundings via the GFS even supporting a few
thunderstorms. The NAM on the other hand, is much quicker to bring
a midlevel dry slot into the northeastern zones quickly shutting
down any chance for afternoon convection. Given the better
agreement amongst the GFS/ECMWF we have trend the forecast toward
the later keeping a slight chance for thunderstorms...but
confidence is generally below normal related to the thunder
threat.
The pattern would also favor breezy to gusty winds for the
Okanogan Valley given the north to south pressure gradient and
cold advection. Consequently, we have increased winds above model
guidance to sustained speeds of 10-18 mph with gusts in the 20-30
mph range. While these winds are well below any highlight-able
thresholds...it will present an elevated threat for wildfire
growth in grass, brush, and other fine fuels given the combination
of relative humidities in the 20`s. /sb
Friday night through Tuesday: Trough continues to exit to the east
along the US/Canadian boarder. A ridge builds in. The thermal
trough that has been suppressed to the south for the last several
days will once again set up across the intermountain west.
Daytime temperatures will warm to slightly above average temps by
Saturday. Sunday will be the warmest day with temps 5-9 degrees
above average. Monday and Tuesday we will remain above average as
well. There are still some model discrepancies of what do do with
a low that develops off the northern CA coast. The 12z ECMWF is
not as bullish in bringing the low across the entire Pac NW as a
weaker open wave. It does show a very weak wave and associated
moisture moving up from the desert southwest. It also shows a strong
closed low moving south out of Canada and has it moving across
northern WA and ID starting early Tuesday. The GFS on the other
hand brings some energy and moisture from the desert southwest
into our southeastern WA and central ID areas. The possible low
from Canada stays way to the north and has no real weather impact
on us. Given both models do show the possible monsoonal moisture
streaming up with a disturbance, have decided to keep the mention
of thunderstorms across the Blue Mountains and the Camas Prairie
for Sunday and have increased cloud cover a bit. /Nisbet
&&
.AVIATION...
18Z TAFS...A weak upper level disturbance will track through E WA
and N ID through 03z. This will result in a slight chance of -tsra
near the Canadian border...but little chance at the TAF sites.
Forecast will be clear with VFR conditions. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 56 84 58 83 55 84 / 0 0 0 10 10 10
Coeur d`Alene 55 84 57 80 53 84 / 0 0 0 10 10 10
Pullman 49 82 51 80 49 82 / 0 0 0 10 0 0
Lewiston 60 90 62 90 61 90 / 0 0 0 0 0 0
Colville 52 88 56 85 51 89 / 0 0 10 20 10 10
Sandpoint 49 84 52 80 49 84 / 0 0 10 20 20 10
Kellogg 53 84 53 79 51 81 / 10 0 0 10 10 10
Moses Lake 56 89 60 88 57 89 / 0 0 0 0 0 0
Wenatchee 61 88 63 88 62 91 / 0 0 0 0 0 0
Omak 60 89 59 86 55 90 / 0 0 10 10 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$