Wednesday, March 31, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 010420
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1120 PM CDT WED MAR 31 2010

..UPDATE TO AVIATION...

DISCUSSION...

WARM AND BREEZY CONDITIONS PREVAILED OVER EXTREME SOUTHEAST KANSAS
AND THE MISSOURI OZARKS. LOW PRESSURE WAS STRENGTHENING ACROSS
SOUTHWEST KANSAS UNDERNEATH A RIDGE OF HIGH PRESSURE ALOFT. WITH
FULL SUNSHINE UNDERWAY...TEMPERATURES SOARED INTO THE 80S IN
SEVERAL LOCATIONS.

FOR TONIGHT...THE OZARKS WILL REMAIN POSITIONED WITHIN A WARM
SECTOR OF A SLIGHTLY MODIFYING AIR MASS. SOME LOW LEVEL MOISTURE
RETURN CAN NOT BE RULED OUT...HOWEVER...925-850MB MOISTURE
TRANSPORT VECTORS SUGGEST THAT AN ELEVATED MIXED LAYER CONTINUES
TO STREAM IN FROM THE WESTERN DESERTS. AT THE SURFACE...DEW
POINTS HAVE INCREASED INTO THE MID 50S ACROSS EASTERN TEXAS. IT'S
THIS INCREASE IN SURFACE DEW POINTS THAT MAY PROVIDE THE REGION
WITH BETTER CHANCES FOR THUNDERSTORMS AS WE HEAD INTO FRIDAY
EVENING AND NIGHT.

AN INTENSE UPPER LEVEL SHORT WAVE AND ASSOCIATED PACIFIC COLD
FRONT WILL APPROACH THE REGION FRIDAY EVENING. THIS FEATURE WILL
FORCE A BAND OF SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS KANSAS
AND OKLAHOMA FRIDAY AFTERNOON. MODELS CONTINUE TO OVER EXAGGERATE
LOW LEVEL MOISTURE INFLUX FROM THE GULF. THIS IS LIKELY DUE TO A
SEVERELY BEATEN GULF OF MEXICO THAT IS STRUGGLING TO CREATE
QUALITY MOISTURE CONTENT. WHILE MODELS ARE SUGGESTING UP TO 500
J/KG OF M.L CAPE WITH UP TO 1000 J/KG OF MU CAPE...THESE VALUES
MAY NOT MATERIALIZE.

HOWEVER...IF THE EAST TEXAS MID 50 DEW POINT AIR MASS CAN ADVECT
INTO SW MO PRIOR TO FRIDAY EVENING...WHICH I THINK WILL
HAPPEN...SUFFICIENT INSTABILITY WILL BE PRESENT FOR A BAND OF
THUNDERSTORMS TO IMPACT SE KANSAS AND SOUTHERN MISSOURI. GIVEN THE
FORECASTED SHEAR IN ADVANCE OF THIS APPROACHING SHORTWAVE...A FEW
STRONG TO SEVERE THUNDERSTORMS CAN NOT BE RULED OUT. KEEP IN MIND
THOUGH...THIS RISK SEEMS VERY MODEST AT THIS TIME...BUT THE EARLY
EVENING TIMING OF THESE THUNDERSTORMS MAY HELP BOOST INSTABILITY
LEVELS JUST ENOUGH FOR SOME STRONG STORMS. FLOODING MAY BE
DIFFICULT TO COME BY AS THIS SYSTEM SHOULD BE PROGRESSIVE ENOUGH
TO MITIGATE AN EXTENDED PERIOD OF TRAINING CONVECTION.

LINGERING CONVECTION IS NOT COMPLETELY OUT OF THE QUESTION FOR
SATURDAY MORNING...PARTICULARLY OUT OVER THE EASTERN OZARKS. BUT
FOR THE MOST PART...MOST LOCATIONS MAY EXPERIENCE MOSTLY DRY AND
MILD CONDITIONS AS THE WAVE QUICKLY ADVANCES INTO THE UPPER
MIDWEST. LOOK FOR FAIR WEATHER BY SATURDAY AFTERNOON WITH HIGHS
IN THE 60S. EVEN WARMER WEATHER IS FORECASTED FOR EASTER SUNDAY AS
READINGS SHOOT BACK INTO THE 70S.

UPPER RIDGING BUILDS BACK INTO THE NATIONS MID SECTION SUNDAY
NIGHT INTO MONDAY. THERE ARE SOME INDICATIONS THAT A WARM FRONT
TRANSLATING NORTHWARD ACROSS SOUTHERN MISSOURI ON MONDAY COULD
TRIGGER SOME MINOR CONVECTION. THIS SMALLER DETAIL WILL BE BETTER
UNDERSTOOD WITH TIME AND IS MORE OF A SHORT TERM FORECAST
CHALLENGE CLOSER TO WHEN THE WARM FRONT PASSES THROUGH.

ANOTHER DECENT SHORTWAVE IS PROGGED BY BOTH THE GFS AND THE ECMWF
SOMETIME AROUND THE TUESDAY OR TUESDAY NIGHT TIME FRAME. THIS
FEATURE WOULD LIKELY CAUSE ANOTHER EPISODE OF CONVECTION TO SPREAD
INTO SOUTHERN MISSOURI.

CRAMER

&&

AVIATION...

FOR THE 06Z TAFS...MAIN AVIATION HAZARD WILL BE WITH WINDS. LOW
LEVEL WIND SHEAR WILL CONTINUE OVERNIGHT INTO THURSDAY MORNING.
JOPLIN WILL CONTINUE TO GUST OVERNIGHT HOWEVER WINDS AT SGF/BBG
HAVE LOST GUSTINESS. WITH MIXING BY MID MORNING THURSDAY...GUSTS
WILL RETURN AT ALL STATIONS. VFR CONDITIONS EXPECTED THROUGH THE PERIOD.

LINDENBERG

&&

FIRE WEATHER...

THE RED FLAG WARNING WILL CONTINUE THROUGH 7 PM. RH VALUES THROUGH
2-230 PM GOT DOWN INTO THE 25-30 PERCENT RANGE WITH 10M
WINDS/AIRPORT SITES GENERALLY AROUND 20 MPH AND GUSTS NEAR 30 MPH.
STRONGEST OVERALL WIND GUSTS OCCURRED AS INVERSION WEAKENED LATE THIS
MORNING MIXING DOWN STRONG LOW LEVEL WINDS. THERE IS SOME SUBTLE
INDICATION OF SOME MODIFIED GULF AIR IS MAKING ITS WAY INTO THE
FAR WESTERN CWFA...AND EXPECT THIS TREND TO CONTINUE (AS MENTIONED
IN THE GENERAL DISCUSSION)...ALBEIT SLOWLY...FROM WEST TO EAST.
FOR TONIGHT...WITH SOUTH WINDS CONTINUING...DO NOT EXPECT GREAT
HUMIDITY RECOVERY AGAIN TONIGHT WITH A CONTINUED HEIGHTENED FIRE
DANGER. AS WITH PAST SHIFTS...STRAIGHT MODEL GUIDANCE IS FAIRLY
USELESS FOR DEW POINTS...AND GRIDS ARE MODIFIED DOWNWARD.

FOR THU...WITH SOMEWHAT HIGHER RH/DEW POINTS EXPECTED...IN
COORDINATION WITH SOME SURROUNDING OFFICES...WILL NOT GO WITH A
WATCH...BUT NEXT SHIFTS WILL NEED TO MONITOR. GUSTY SOUTH WINDS
WILL BE A LITTLE STRONGER THAN TODAY AND A HEIGHTENED FIRE DANGER
IS EXPECTED TO CONTINUE...BUT RH VALUES ARE EXPECTED TO REMAIN
ABOVE RED FLAG WARNING CRITERIA. DSA

&&

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

$$


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