Sunday, October 24, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 241122
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
622 AM CDT SUN OCT 24 2010

..UPDATE TO AVIATION...

DISCUSSION...
/ISSUED 251 AM CDT SUN OCT 24 2010/

SHORT TERM (TODAY THROUGH TUESDAY)...

REGION REMAINS SITUATED THIS MORNING UNDER SWIFT SOUTHWEST
FLOW...WITH LARGE UPPER LOW CENTERED OVER CENTRAL NEBRASKA THIS
MORNING. WATER VAPOR IMAGERY DEPICTS STRONG SHORTWAVE PASSING
THROUGH CWA AS OF 0630Z...WITH SUBSIDENCE BEHIND IT NOT ONLY
PUTTING THE KIBOSH ON THE SHOWER ACTIVITY...BUT AT LEAST FOR THE
TIME...SCOURING OUT MOST IF NOT ALL OF THE CLOUD COVER IN ITS
WAKE. CAREFUL EXAMINATION OF GOES FOG CHANNEL...HOWEVER...SUGGESTS
THAT ANY CLEARING MAY BE SHORT-LIVED...WITH SLOW STRATUS BEGINNING
TO FORM IN EAST-CENTRAL KANSAS AND PORTIONS OF OKLAHOMA. WOULDN'T
BE TERRIBLY SURPRISED TO SEE SOME OF THAT CLOUD COVER EVENTUALLY
EXPAND NORTH INTO THE CWA THIS MORNING.

LATER THIS MORNING AND PARTICULARLY THIS AFTERNOON...THINK THAT
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY WILL ONCE AGAIN BE
POSSIBLE...THOUGH MAINLY EAST OF U.S. 65. LOW LEVEL MOISTURE
RETURN CONTINUES TO BE A CONCERN...ALONG WITH NOT ONLY DEGREE
OF...BUT ALSO ORGANIZATION OF BOTH SURFACE AND UPPER LEVEL FORCING
FOR STORM INITIATION. EASTERN HALF OF THE FORECAST AREA TO BE
SITUATED UNDER BROAD AREA OF UPPER LEVEL DIFLUENCE/LEFT EXIT
REGION OF UPPER LEVEL JET...AND SHORT TERM GUIDANCE IS SUGGESTIVE
OF SHEARED UPPER VORT ROTATING THROUGH THE AREA EARLY THIS
AFTERNOON...BOTH OF WHICH MAY LEND SOME FORCING FOR CONVECTIVE
INITIATION. SURFACE ORGANIZATION IS GOING TO BE TOUGH TO COME
BY...WITH NO PARTICULARLY STRONG AREA OF CONVERGENCE PROGGED TO BE
IN THE VICINITY DURING THE DAY TODAY. SPC DY1 OUTLOOK DOES PLACE
AREAS FROM ROUGHLY A NEOSHO TO SPRINGFIELD TO VICHY LINE IN A
SLIGHT RISK FOR SEVERE WEATHER THIS AFTERNOON/EVENING. AS NOTED IN
SPC DISCUSSION...BETTER INSTABILITY AND UPPER FORCING TO BE WELL
SOUTH OF THE SGF CWA...BUT IF ENOUGH INSTABILITY IS ABLE TO
FORM...SHEAR MAGNITUDES ARE HIGH ENOUGH FOR CONVECTIVE
ORGANIZATION. ANY STRONG STORMS WOULD BE PRIMARILY CAPABLE OF
LARGE HAIL AND PERHAPS A FEW STRONG WIND GUSTS.

500 MB TROUGH FINALLY CLEARS THE AREA LATE TONIGHT/EARLY MONDAY
MORNING...AND STILL ANTICIPATE MOST OF THE DAYTIME HOURS MONDAY
BEING DRY. NO TRUE SURFACE FRONT EVER CLEARS THE AREA WITH
AFOREMENTIONED TROUGH...SO EXPECT MONDAY TO BE A DRY...BUT VERY
WARM AND RATHER WINDY DAY. CURRENT HIGHS MONDAY EXPECTED TO RANGE
FROM THE UPPER 70S TO LOW 80S. THIS WILL BE FLIRTING WITH RECORD
HIGHS MONDAY...WHICH ARE 83 FOR JLN/VIH/UNO AND 85 FOR SGF.

BY MONDAY NIGHT...VERY STRONG STORM SYSTEM PROGGED TO PLOW INTO
THE CENTRAL PLAINS. EXPECT THIS TO DRAG A STRONG AND SWIFT-MOVING
UPPER TROUGH AND FRONTAL BOUNDARY ACROSS THE REGION LATE MONDAY
NIGHT AND TUESDAY. THIS WILL RESULT IN RAPID INCREASE IN
SHOWER/THUNDERSTORM POTENTIAL MONDAY EVENING THROUGH TUESDAY
MORNING...AS WHAT WILL LIKELY BE A LARGE AREA OF SHOWERS WITH A
FEW EMBEDDED THUNDERSTORMS SWEEP ACROSS THE AREA. REMNANT SHOWERS
AND THUNDERSTORMS SHOULD BE CLEARING THE FAR EASTERN FORECAST AREA
TUESDAY...WITH HIGHS ON TUESDAY LIKELY THE BETTER PART OF 10-15
DEGREES COOLER THAN ON MONDAY.

BOXELL

LONG TERM (TUESDAY NIGHT THROUGH SATURDAY)...

00Z SUITE OF MODEL GUIDANCE OFFERS GOOD CONTINUITY WITH PRIOR
SOLUTIONS AND INTER MODEL AGREEMENT REMAINS ON THE HIGH SIDE. A
LARGE UPPER LOW WILL BE IN THE PROCESS OF FILLING ACROSS THE UPPER
MIDWEST. THIS FEATURE WILL KEEP A BROAD TROUGH OVER THE MIDWEST
UNTIL THURSDAY AS IT WILL THEN MOVE NE INTO EASTERN CANADA. A COLD
FRONT SHOULD CLEAR THE REGION TUESDAY NIGHT...AND A GRADUAL COOLING
TREND IS EXPECTED WED/THUR WITH TEMPS AT OR JUST BELOW AVG
EXPECTED.

A LARGE AREA OF HIGH PRESSURE (OF PACIFIC ORIGINS) WILL SLIDE
EASTWARD INTO THE MIDWEST DURING THE THUR/FRI TIME FRAME. COOLEST
DAY OF THE PERIOD LOOKS TO BE THURSDAY/THURSDAY NIGHT. WILL NEED
TO KEEP AN EYE ON LOW TEMPS THURSDAY NIGHT. RAW MODEL DEWPOINT
PROGS ARE IN THE UPPER 20S/LOWER 30S AND WITH HIGH PRESSURE
OVERHEAD...THERE IS THE POTENTIAL FOR RADIATIONAL COOLING WHICH
COULD RESULT IN PORTIONS OF THE AREA FLIRTING WITH THE FREEZING
MARK. FOR NOW...HAVE TRENDED LOWS CLOSE TO THE COOLER MEX NUMBERS
(MID 30S). A WARMING TREND IS ON TAP FOR FRIDAY INTO SATURDAY.
SFC HIGH PRESSURE WILL SLIDE OFF TO THE EAST AS RIDGING ALOFT
BUILDS INTO THE REGION. THIS WILL GET TEMPS BACK TO NEAR AVG FOR
FRI AND ABOVE AVG FOR SAT. NO RAIN IS EXPECTED IN THE EXTENDED
FORECAST.

GAGAN

&&

AVIATION...

FOR THE 12Z TAFS...

INITIAL CONCERN THIS MORNING IS LOW STRATUS DECK DEVELOPING EAST
FROM KANSAS THAT WILL LIKELY IMPACT KJLN THROUGH ABOUT 14Z. EXPECT
CIGS TO DROP TO LOW END MVFR/OCCASIONAL IFR AT TIMES WITH THIS
AREA OF CLOUDS.

LATER THIS AFTERNOON...SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE MAINLY AFFECTING KSGF AND KJLN. TIMING/COVERAGE STILL
UNCERTAIN...SO HAVE ONLY INCLUDED CB MENTION FOR NOW.
OTHERWISE...WINDS WILL REMAIN GUSTY FROM THE SOUTH TODAY.

SKIES EXPECTED TO CLEAR FROM WEST TO EAST VERY LATE TONIGHT...AS
WINDS FINALLY BEGIN TO SUBSIDE.

BOXELL

&&

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

$$

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