Wednesday, July 28, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 290238
NATIONAL WEATHER SERVICE SPRINGFIELD MO
938 PM CDT WED JUL 28 2010

..MESOSCALE CONVECTIVE DISCUSSION...

UPDATE...

THE LAST OF THE DIURNALLY DRIVEN PULSERS ARE NOW WANING ON RADAR.
MEANWHILE...STORMS ARE STRUGGLING TO DEVELOP ALONG THE COLD FRONT
SITUATED ACROSS NORTHERN MISSOURI. ALTHOUGH THE FRONT CONTINUES TO
MOVE SOUTH...IT IS LOSING MOMENTUM AS THE ONLY REAL PRESSURE RISES
OF NOTE ARE CONVECTIVELY INDUCED ACROSS SOUTHERN IOWA AND WEST
CENTRAL ILLINOIS. ALTHOUGH THE FRONT MAY APPROACH OUR FAR NORTHERN
COUNTIES LATE TONIGHT...IT IS EXPECTED TO BE TOO SHALLOW TO INDUCE
ELEVATED CONVECTION. WITH OTHER TRIGGERING MECHANISMS
LACKING...THE ONLY SHOT AT LATE NIGHT CONVECTION WILL BE A MATURE
COLD POOL. UNLESS SOMETHING GETS GOING UP ACROSS NORTHERN MISSOURI
SOON...THE CHANCES OF THIS LOOK PRETTY SLIM. WILL BE TRIMMING THE
SOUTHERN EXTENT OF SLIGHT CHANCE POPS FOR THE REST OF TONIGHT.
FURTHER TRIMMING MAY BE NEEDED IF THE LINE FAILS TO MATERIALIZE UP
NORTH.

SCHAUMANN

&&

DISCUSSION...

WE ARE SEEING CONVECTION BEGINNING TO DEVELOP ONCE AGAIN EARLY THIS
AFTERNOON ACROSS THE SOUTHEASTERN CWA. WHILE INITIAL CONVECTIVE
DEVELOPMENT HAS BEEN ACROSS THE SOUTHEAST...MODIFICATION OF THE 12Z
SGF RAOB INDICATES THAT THE ENTIRE CWA WILL LIKELY BECOME UNCAPPED
THIS AFTERNOON...AND CURRENTLY ANTICIPATE SEEING AN EXPANSION OF
SCATTERED CONVECTION ACROSS THE AREA. WIND SHEAR REMAINS VERY
WEAK...AND WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED THIS
AFTERNOON. PWATS REMAIN NEAR OR ABOVE 2 INCHES...AND VERY SLOW
STORM MOTIONS WILL RESULT IN A LOCALIZED FLASH FLOODING THREAT. AS
HAS BEEN THE CASE THE LAST FEW DAYS...CONVECTION IS LARGELY EXPECTED
TO DISSIPATE AROUND SUNSET.

ONLY EXCEPTION TO THIS MAY BE ACROSS THE U.S. 54 CORRIDOR...WHERE
APPROACHING FRONTAL BOUNDARY CURRENTLY ANALYZED FROM NEAR OMAHA
EAST ACROSS CENTRAL IOWA AND SOUTHERN WISCONSIN MAY SERVE AS A FOCUS
LATE TONIGHT FOR ADDITIONAL CONVECTION. FRONTAL BOUNDARY IS
EXPECTED TO TURN INCREASINGLY PARALLEL TO THE UPPER LEVEL FLOW
TONIGHT AND INTO THE DAY ON THURSDAY...RESULTING IN A SLOWING AND
EVENTUAL STALLING ACROSS THE EAST-CENTRAL CWA. CONVERGENCE ALONG
THIS FRONT IS QUITE WEAK...AND WHILE THE NORTHERN CWA WILL BE ON THE
SOUTHERN PERIPHERY OF RELATIVELY STRONGER NORTHWEST FLOW...STILL
BELIEVE THAT CONVECTION WILL LARGELY BE DIURNALLY DRIVEN THURSDAY
AND THURSDAY NIGHT. RIGHT NOW...DON'T ANTICIPATE ANY SIGNIFICANT
SEVERE WEATHER IN THE VICINITY OF THE FRONT...BUT AS MENTIONED
ABOVE...SOMEWHAT STRONGER FLOW WILL BE IN PLACE...SO COULDN'T RULE
OUT SLIGHTLY BETTER ORGANIZATION TO CONVECTION AT TIMES
THURSDAY/THURSDAY EVENING.

FRONTAL BOUNDARY THEN EXPECTED TO MIX NORTH FRIDAY/FRIDAY NIGHT AS A
WARM FRONT. MODEL GUIDANCE IS HINTING AT MCS DEVELOPMENT ACROSS
NEBRASKA/WESTERN IOWA FRIDAY NIGHT...WHICH COULD RESULT IN A
SMATTERING OF SHOWERS/THUNDERSTORMS ACROSS THE EXTREME NORTHERN CWA
THROUGH SATURDAY MORNING. OBVIOUSLY...EVENTUAL OVERNIGHT CONVECTIVE
CHANCES WILL BE HIGHLY DEPENDENT ON TIMING AND PLACEMENT OF MCS
DEVELOPMENT (ASSUMING THAT ONE EVEN DOES FORM)...SO JUST MAINTAINED
SLIGHT CHANCE TO CHANCE POPS ACROSS THE NORTHERN AND NORTHEASTERN
HALF OR SO OF THE CWA FRIDAY NIGHT AND SATURDAY.

DEEP AND LIKELY CAPPED WARM SECTOR ESTABLISHES ITSELF BACK OVER THE
CWA SUNDAY AND MONDAY...WITH STRONG SURFACE THETA-E ADVECTION REALLY
CRANKING UP MONDAY. TEMPERATURES WILL LIKELY SURGE INTO MID TO
UPPER 90S ACROSS THE AREA...WITH THE HIGH SOIL/VEGETATIVE MOISTURE
CONTENT SERVING AS PERHAPS THE ONLY SAVING GRACE IN PREVENTING TEMPS
FROM BREAKING THE CENTURY MARK.

NEXT TUESDAY AND WEDNESDAY...MODEL GUIDANCE IS HINTING AT DEVELOPING
A COLD FRONT ACROSS THE EASTERN PLAINS/MISSOURI VALLEY AND DROPPING
IT SOUTH ACROSS THE REGION. BROAD BRUSHED SLIGHT CHANCE POPS ACROSS
THE AREA FOR THE END OF THE FORECAST PERIOD...WITH LINGERING DOUBTS
ABOUT JUST HOW FAR SOUTH ANY FRONT WILL MAKE IT.

BOXELL

&&

AVIATION...

ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS PORTIONS OF
SOUTHWESTERN MISSOURI INTO EARLY THIS EVENING. DO NOT EXPECT ANY
OF THIS ACTIVITY TO DIRECTLY AFFECT THE AERODROMES...SO HAVE ONLY
INCLUDED PREVAILING CB AT KSGF AND KBBG. MAY SEE A SLIGHT
REDUCTION TO VISIBILITY LATE TONIGHT DUE TO A SLIGHT INCREASE IN
LOW LEVEL MOISTURE. WENT WITH A 6 MILE PREVAILING GROUP FOR NOW
LATE TONIGHT AND WILL CONTINUE TO ASSESS THROUGHOUT THE EVENING.
ANY REDUCTION TO VISIBILITY WILL DIMINISH BY MID MORNING ON
THURSDAY.

SCHAUMANN

&&

SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

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