Thursday, July 29, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 291714
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1214 PM CDT THU JUL 29 2010

UPDATE...

JUST A FEW MINOR ADJUSTMENTS TO NEAR TERM FORECAST THIS
MORNING...WITH MAIN FOCUS REMAINING ON CONVECTIVE CHANCES LATE
THIS MORNING AND THIS AFTERNOON.

15Z SURFACE ANALYSIS SHOWS WEAK FRONTAL BOUNDARY FROM ROUGHLY
KANSAS CITY TO COLUMBIA TO ST. LOUIS. SO FAR THIS MORNING...ONLY
REFLECTION OF THIS FRONT HAS BEEN IN AN ACCAS FIELD IN ITS
VICINITY. RUC/SPC MESOANALYSIS INDICATES THAT ATMOSPHERE IS
BECOMING A BIT MORE UNSTABLE ACROSS THE AREA...WITH MODIFICATION
OF THE 12Z SGF SOUNDING CONFIRMING THAT MLCIN SHOULD QUICKLY
DISSIPATE AS SFC TEMPS WARM INTO THE UPPER 80S TO NEAR 90. AS
SUCH...AM STILL ANTICIPATING ISOLATED TO SCATTERED CONVECTION TO
FORM EARLY THIS AFTERNOON. 0-6 KM SHEAR VECTORS ARE CURRENTLY
BELOW 10 KTS PER 12Z RAOB...BUT SHORT TERM RUC ANALYSIS INDICATES
THAT WE COULD SEE A MODEST INCREASE IN SHEAR...INTO THE 15-20 KT
RAGE...THIS AFTERNOON AS SLIGHTLY FASTER MID AND UPPER FLOW FLOW
IMPINGES ON THE BOUNDARY. SEVERE WEATHER EXPECTATIONS ARE STILL
QUITE LOW...WITH 2 INCH PWATS STILL SUGGESTING THAT HEAVY RAIN AND
A LOCALIZED FLASH FLOODING THREAT WILL BE THE BIGGEST PLAYER THIS
AFTERNOON.

OTHER MINOR CHANGE THIS MORNING WAS TO INSERT SLIGHT
CHANCE/ISOLATED POPS ACROSS EASTERN KANSAS AND FAR WESTERN
MISSOURI WHERE A FEW VERY SMALL CONVECTIVE CELLS HAVE MANAGED TO
GET GOING. WHILE WELL AWAY FROM THE SURFACE FRONT...WATER VAPOR
IMAGERY WOULD SUGGEST VERY WEAK UPPER LEVEL ENERGY DROPPING SOUTH
ACROSS NORTHERN KANSAS...AND THE APPROACH OF THIS FEATURE LOOKS TO
BE PROVIDING JUST ENOUGH LIFT TO SET OFF A FEW SCATTERED
SHOWERS/THUNDERSTORMS.

BOXELL

&&

DISCUSSION...

MAIN FOCUS WITH THIS FORECAST PACKAGE WILL BE WITH CONVECTIVE
PRECIPITATION CHANCES IN THE SHORT TERM AND THE RETURNING HEAT
DURING THE EXTENDED PERIOD.

CURRENTLY...SURFACE FRONT WAS LOCATED NEAR THE I70 CORRIDOR EARLY
THIS MORNING WITH SOME WANING CONVECTION STRETCHING FROM NEAR
COLUMBIA TO NEAR LEXINGTON. NOT MUCH UPPER SUPPORT AND FRONTAL
CONVERGENCE IS FAIRLY WEAK. UPPER LEVEL RIDGE AXIS WAS FROM THE
LOWER MISSISSIPPI VALLEY INTO THE CENTRAL HIGH PLAINS.

FORECAST...WEAK FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY
OVER THE NORTHEAST CWA TODAY...SETTING UP NEARLY PARALLEL TO THE
UPPER LEVEL FLOW. ATMOSPHERE WILL AGAIN BECOME UNSTABLE BY LATE
MORNING THROUGH THE EVENING AND COULD SEE SOME PULSE THUNDERSTORMS
DEVELOP OVER THE CWA ALONG WITH SOME THUNDERSTORMS DEVELOPING
ALONG THE SURFACE FRONT. CERTAINLY NOT EXPECTING WIDESPREAD
THUNDERSTORM DEVELOPMENT WITH LITTLE TO NO UPPER SUPPORT. SEVERE
STORMS NOT EXPECTED EITHER WITH WEAK SHEAR CONTINUING OVER THE
CWA. WOULD EXPECT STORMS TO BEGIN DIMINISHING AGAIN DURING THE MID
TO LATE EVENING. HIGHS WILL LIKELY BE SIMILAR TO PAST COUPLE OF
DAYS WITH READINGS AROUND 90 TO 93 ACROSS THE CWA. OVERNIGHT LOWS
THROUGH THE PERIOD WILL REMAIN WARM AND MUGGY.

FRONT WILL GRADUALLY LIFT BACK TO THE NORTHEAST AS A WARM FRONT ON
FRIDAY. THUNDERSTORM COVERAGE WILL BEGIN TO DIMINISH BY FRIDAY AND
SATURDAY AS UPPER RIDGE BECOMES MORE DOMINANT AND THERMAL CAP
INCREASES. TEMPERATURES WILL ALSO BEGIN TO INCREASE WITH HIGHS
GENERALLY IN THE MID 90S EVERYWHERE BY SATURDAY AND PUSHING INTO
THE UPPER 90S BY LATE IN THE WEEKEND AND EARLY NEXT WEEK. LOOKING
AT FORECASTED HEAT INDEX VALUES FROM 100 TO 107 HEADING INTO THE
WEEKEND AND MAY BE NEEDING SOME HEAT HEADLINES ONCE AGAIN.

LINDENBERG

&&

AVIATION...

FOR THE 18Z TAFS...SCT RA/TSRA CONTINUES TO DEVELOP EARLY THIS
AFTERNOON. CURRENTLY HAVE JUST INDICATED VCTS AT ALL THREE
TERMINALS AS CONVECTIVE DEVELOPMENT IS EXPECTED TO BE RATHER
UNFOCUSED IN NATURE. SHOULD TSRA MOVE OVER AN AIRFIELD
HOWEVER...BRIEF PERIODS OF MVFR TO IFR CIGS AND VIS CAN BE
EXPECTED. OTHERWISE...CIGS SHOULD REMAIN LOW END VFR THROUGH THE
AFTERNOON OUTSIDE OF TSRA.

CONVECTION SHOULD DISSIPATE AROUND SUNSET TONIGHT. SOME INDICATION
RIGHT NOW THAT A THUNDERSTORM COMPLEX COULD FORM OVER
NEBRASKA/IOWA AND DROP SOUTH OVERNIGHT...THOUGH CONFIDENCE IS
EXTREMELY LOW AND THUS HAVE LEFT OUT ANY MENTION OF TSRA
OVERNIGHT ATTM. OTHER POSSIBLE ISSUE OVERNIGHT COULD BE MVFR
HZ/BR...ESPECIALLY AT ANY TERMINAL THAT SEES PRECIPITATION TODAY.
HOWEVER...WILL LEAVE IT TO LATER SHIFTS TO FINE TUNE THIS
POSSIBILITY.

BOXELL

&&

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

$$

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