Saturday, July 24, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 250033
NATIONAL WEATHER SERVICE SPRINGFIELD MO
733 PM CDT SAT JUL 24 2010

UPDATE...
/ISSUED 725 PM CDT SAT JUL 24 2010/

LINE OF THUNDERSTORMS HAS FILLED IN OVER THE LAST 90 MINUTES
AHEAD OF A COLD FRONT THAT EXTENDS FROM NE MO INTO EAST CNTRL KS.
AWOS/ASOS STATION OVER CNTRL MO HAVE REPORTED GENERALLY 35-40KT
GUSTS ALONG THE LEADING EDGE OF THE STORMS (CLINTON/WARSAW).
INSTABILITY IS STILL STRONG...AND HAVE SEEN SOME ISOLATED SMALL
STRONGER UPDRAFTS CAPABLE OF SOME SMALL HAIL. WILL NEED TO WATCH
TRENDS. HAVE SIG WEATHER ALERTS FOR SOME CENTRAL MO COUNTIES. IN
GENERAL...LOOKS LIKE THE OVERALL SEVERE WEATHER THREAT WILL BE
MARGINAL BUT CERTAINLY NOT NIL. IN GENERAL...WITH THE LOSS OF
DAYTIME HEATING...THE GENERAL TREND LATER THIS EVENING WILL BE FOR
THE CONVECTION TO WEAKEN.

NO DOUBT A NICE SHELF CLOUD ALONG THE LEADING EDGE OF THESE
STORMS. HAVE ALREADY HAS A COUPLE OF REPORTS TO THAT EFFECT.

WILL NEED TO WATCH HYDRO TRENDS GIVEN THE SLOW MOVEMENT OF STORMS.

DSA

&&

DISCUSSION...
/ISSUED 306 PM CDT SAT JUL 24 2010/
THE FOCUS FOR THE FORECAST REMAINS ON THE FRONT...NOW ACROSS
NORTHERN MISSOURI...AND WHERE IT DECIDES TO END UP. THIS WILL HAVE
IMPACTS ON PRECIPITATION TODAY AND INTO SUNDAY. IN ADDITION WILL
NEED TO KEEP AN EYE ON THE RESIDUAL MOISTURE AND CIRCULATION LEFT
FROM TROPICAL DEPRESSION BONNIE.

MODELS CONTINUE TO PUSH THE COLD FRONT INTO THE OZARKS THIS
EVENING WITH THE POTENTIAL OF STRONG TO SEVERE THUNDERSTORMS
DEVELOPING ALONG THE FRONT. THE FRONT WILL PROVIDE THE LIFT NEEDED
FOR THUNDERSTORM DEVELOPMENT AND WILL BE ABLE TO TAKE ADVANTAGE OF
THE 4000 J/KG OF INSTABILITY AVAILABLE ACROSS THE REGION. WHILE
THERE IS PLENTY OF INSTABILITY...LITTLE IN THE WAY OF WIND
SHEAR WILL BE AVAILABLE FOR STORMS TO TAKE ADVANTAGE OF. THE 18Z
SOUNDING FROM SPRINGFIELD DOES INDICATE AT LEAST THE POSSIBILITY
OF A HIGH WIND THREAT WITH ANY STORMS THAT DEVELOP THOUGH THE HAIL
RISK REMAINS LIMITED WITH A FREEZING LEVEL REMAINING OVER 16KFT.
SO STILL THINKING THAT THE GREATEST RISK FROM STRONG TO SEVERE
THUNDERSTORMS REMAINS WIND GUSTS OVER 60MPH AND ISOLATED HAIL TO
THE SIZE OF QUARTERS.

PRECIPITABLE WATER VALUES ACTUALLY WENT UP ABOUT 0.10 INCHES FROM
THE 12Z SOUNDING WITH PWATS AROUND 2 INCHES. WITH THE AVAILABLE
MOISTURE IN PLACE WOULD EXPECT THAT STORMS WOULD BE EFFICIENT
RAINFALL PRODUCERS AS WE HAVE SEEN WITH STORMS THAT HAVE DEVELOPED
IN THIS WARM AND MUGGY AIR MASS OVER THE PAST WEEK. THE POTENTIAL
OF RAINFALL RATES EXCEEDING AN INCH PER HOUR IS POSSIBLE AND THE
POTENTIAL FOR ISOLATED FLASH FLOODING WILL NEED TO BE MONITORED.

THE FRONT WILL LIFT NORTH OF THE REGION TO START THE WEEK MOVING
THE OZARKS ONCE AGAIN INTO THE WARM SECTOR. THE UPPER LEVEL RIDGE
WILL BEGIN TO REASSERT ITSELF ACROSS THE REGION. THIS IS WHERE
SOME UNCERTAINTY IS WITH REGARDS TO THE REMNANTS OF BONNIE. THE
TROPICAL SYSTEM IS EXPECTED TO REMAIN UNDER THE UPPER HIGH AND
WANDER ACROSS THE REGION THROUGH MID WEEK AS THE WESTERLY
STEERING FLOW REMAINS WELL NORTH OF THE REGION. THIS WOULD AT THE
VERY LEAST ALLOW FOR THE CHANCE OF DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS EACH AFTERNOON THROUGH THURSDAY.

THE EXTENDED MODELS ATTEMPT TO BRING ANOTHER WEAK COLD FRONT INTO
THE REGION AGAIN NEXT WEEKEND...BUT THIS IS STILL QUITE A WAYS OUT
IN THE FUTURE. BEFORE THIS NEXT FRONT WOULD MOVE INTO THE REGION
THOUGH...TEMPERATURES AND MOISTURE ARE EXPECTED TO
INCREASE...RETURNING HEAT INDEX VALUES TO AROUND 100 DEGREES TO
THE AREA BY THE START OF NEXT WEEKEND.

HATCH

&&

AVIATION...
/ISSUED 444 PM CDT SAT JUL 24 2010/
A COLD FRONT EXTENDING FROM NORTHEAST MO...THROUGH THE KANSAS
CITY METRO AREA...INTO EAST CENTRAL KS WILL BE THE CONTINUED FOCUS
FOR THUNDERSTORMS OVER THE NEXT FEW HOURS. WILL CONTINUE TO
MONITOR TRENDS...BUT IT WOULD APPEAR BETTER CHANCES FOR
THUNDERSTORMS AT KJLN/JOPLIN AND KSGF/SPRINGFIELD WILL HOLD OFF
UNTIL THE FRONT MOVES FARTHER SOUTHEAST INTO THE AREA OVERNIGHT
AND SUNDAY MORNING. SOME SHORT TERM MODELS (LOCAL WRF AND NAM)
APPEAR TO BE TOO AGGRESSIVE IN DEVELOPING CONVECTION WELL SOUTH OF
THE FRONT THIS AFTERNOON. AN 18Z KSGF SOUNDING DID SHOW SOME WEAK
MIXED LAYER CIN...BUT ADJUSTING FOR CURRENT TEMPS...CAP IS
ESSENTIALLY GONE...BUT THERE SO FAR HASN'T BEEN A FOCUS/TRIGGER
FOR DEEP CONVECTION WELL AHEAD OF THE FRONT. FOR NOW WILL MENTION
VCTS/CB REMARKS IN ALL THE TAFS AND THEN MONITOR TRENDS TO TRY TO
BETTER DEFINE WHEN TSTMS WILL AFFECT THE TAF SITES. OUTSIDE OF
MVFR/LOCALIZED IFR CONDITIONS WITH SOME TSTMS...TAF SITES SHOULD
BE VFR WITH A WIND SHIFT TO THE NORTH BY AROUND 25/12Z. WITH FRONT
HANGING CLOSE TO THE TAF SITES SUNDAY...WILL MENTION AGAIN CARRY
VCTS/CB REMARKS AT ALL TAF SITES. DSA

&&

SGF WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR MOZ055>058-066>071-
077>083-088>098-101>106.

KS...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR KSZ073-097-101.

&&

$$

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