Monday, August 30, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 301721
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1221 PM CDT MON AUG 30 2010

..UPDATE TO AVIATION...

UPDATE...

FORECAST GENERALLY ON TRACK TODAY...WITH JUST A FEW TWEAKS THIS
MORNING TO ACCOUNT FOR LATEST RADAR TRENDS.

WATER VAPOR IMAGERY NICELY DEPICTS BROAD VORT LOBES ROTATING
AROUND UPPER RIDGE CENTERED OVER THE MID ATLANTIC. CLOSER
EXAMINATION OF WATER VAPOR AS WELL AS SPC/RUC MESOANALYSIS
SUGGESTS ONE WAVE LIFTING NORTH OVER SOUTHERN ILLINOIS...WITH
ANOTHER LIFTING NORTHEAST OVER SOUTHWESTERN MISSOURI. THINK THAT
MAIN FORCING FOR ONGOING SHRA ACTIVITY OVER THE CENTRAL AND
EASTERN OZARKS IS IN ASSOCIATION WITH THE SHORTWAVE/VORT OVER
SOUTHWESTERN MISSOURI...WHICH SHOULD CONTINUE TO SLOWLY LIFT
NORTHEAST TODAY. FOR THE FORECAST...HAVE UPPED POPS TO
LIKELY/NUMEROUS WORDING FOR FAR SOUTHEAST CWA...WHERE PRECIP WILL
LIKELY PERSIST INTO THE AFTERNOON. FOR NOW...FEEL LIKE CHANCES FOR
SHRA/TSRA OVER AREAS ALONG/WEST OF U.S. LOOK PRETTY LOW...WITH
FORCING BECOMING BETTER SITUATED TO THE EAST OF THIS AREA...AS
WELL AS SLIGHTLY LESS MOISTURE IN PLACE.

BOXELL

&&

DISCUSSION...
/ISSUED 330 AM CDT MON AUG 30 2010/

MAIN FOCUS IN THIS FORECAST PACKAGE WILL DEAL WITH TEMPERATURES
AND SCATTERED SHOWER AND THUNDERSTORM POTENTIAL TODAY...THEN
ATTENTION TURNS TO BETTER CHANCES FOR WIDESPREAD RAINFALL AHEAD OF
AND ASSOCIATED WITH A SURFACE COLD FRONT WEDNESDAY INTO THURSDAY
EVENING.

CURRENTLY...UPPER LEVEL RIDGE OF HIGH PRESSURE REMAINS LOCKED IN PLACE
ACROSS THE EAST COAST AS AN UPPER LEVEL TROUGH IS LOCATED ACROSS
THE WEST COAST. TROPICAL MOISTURE CONTINUES TO MOVE OUT OF THE
GULF INTO THE EASTERN CWA EARLY THIS MORNING. DRIER AIR HOWEVER
REMAINS IN PLACE ACROSS THE WESTERN CWA AND IS SLOWING THE
WESTWARD MOVEMENT OF THE MOISTURE. A LOW LEVEL STRATUS CLOUD DECK HAS
SPREAD INTO THE EASTERN PORTIONS OF THE CWA WITHIN THIS MOISTURE
PLUME. THERE IS ALSO A WEAK UPPER LEVEL DISTURBANCE WITHIN THIS
MOISTURE PLUME ACROSS NORTHERN MISSISSIPPI WHICH IS RESULTING IN A
FEW SHOWERS ACROSS NORTHEASTERN ARKANSAS EARLY THIS MORNING.

THE SHOWER ACTIVITY ACROSS NORTHEASTERN ARKANSAS SHOULD CONTINUE
TO LIFT NORTH INTO SOUTH CENTRAL MISSOURI THIS MORNING. THIS
ACTIVITY WILL BE ISOLATED TO SCATTERED IN NATURE AND OVERALL NOT
OVERLY HEAVY. INSTABILITY SHOULD INCREASE ENOUGH FROM MID MORNING
INTO THE AFTERNOON HOURS TO ALLOW FOR SOME ISOLATED TO SCATTERED
THUNDERSTORMS WITHIN THIS ACTIVITY. NO SEVERE WEATHER IS EXPECTED
WITH THIS ACTIVITY. THE BETTER MOISTURE WILL REMAIN ACROSS THE
EASTERN CWA AND OFF TO THE EAST...WHERE THE CONVECTION SHOULD
REMAIN.

TEMPERATURES WILL BE TRICKY TODAY DUE TO THE CLOUD COVER AND
CONVECTION POTENTIAL TODAY. THE STRATUS DECK WHICH HAS PUSHED INTO THE
AREA...HAS STARTED TO SLOW ITS NORTHWARD AND WESTWARD PUSH EARLY
THIS MORNING...BUT MAY STILL PUSH FARTHER TO THE WEST THIS
MORNING. WITH THE DRY MID LEVEL MOISTURE IN PLACE ACROSS THE WESTERN
CWA THIS CLOUD DECK SHOULD ERODE AND RETREAT BACK TO THE EAST THIS
AFTERNOON IF IT DOES SPREAD INTO THESE AREAS. WITH BETTER
MOISTURE ACROSS THE EASTERN CWA DO NOT KNOW HOW MUCH THIS CLOUD
DECK WILL BE ABLE TO ERODE THIS AFTERNOON THERE. THEREFORE...THINK
CLOUDS WILL HOLD ON ACROSS THE EASTERN CWA FOR MUCH OF THE
DAY...WITH PARTLY CLOUDY SKIES EXPECTED ACROSS THE WESTERN CWA.
EXPECTED TEMPERATURES TO WARM INTO THE 90S ACROSS EXTREME
SOUTHEAST KANSAS AND FAR WESTERN AND SOUTHWESTERN MISSOURI DUE TO
THE EXPECTED BREAKS IN THE CLOUDS AND WITH A WARM AIRMASS STILL IN
PLACE ACROSS THE AREA. THE CLOUD COVER TO THE EAST THOUGH SHOULD
REALLY LIMIT HIGHS THIS AFTERNOON...WITH HIGHS IN THE LOW TO MID
80S EXPECTED. THEREFORE...A TEN DEGREE DIFFERENCE IN HIGHS FROM
THE WESTERN TO EASTERN CWA WILL LIKELY OCCUR THIS AFTERNOON.

THIS EVENING INTO TONIGHT...THE TROPICAL MOISTURE PLUME SHOULD LIFT
TO THE NORTH AND EAST WITH THE DRIER AIRMASS TO THE WEST ALLOWED
TO SPREAD BACK TO THE EAST ACROSS THE ENTIRE AREA. THIS SHOULD LIMIT
ANY PRECIPITATION CHANCES THROUGH THIS PERIOD.

MOISTURE WILL THEN START TO SPREAD INTO THE AREA FROM THE WEST
ON TUESDAY AHEAD OF THE NEXT SYSTEM. THERE WILL BE THE POSSIBILITY
FOR A FEW ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE
AREA...GENERALLY DURING THE PEAK HEATING TIME FRAME. THE BETTER
CHANCES WILL BE ACROSS THE WESTERN CWA WHERE THE BETTER MID LEVEL
MOISTURE WILL RESIDE...HOWEVER THIS ACTIVITY WILL STILL NOT BE
WIDESPREAD BY ANY MEANS.

THE UPPER LEVEL TROUGH WILL PUSH EAST ACROSS THE NORTHERN AND
CENTRAL PLAINS ON WEDNESDAY INTO THURSDAY. THIS FEATURE WILL
FLATTEN THE UPPER LEVEL RIDGE AND ALLOW FOR A COLD FRONT TO PUSH
TOWARDS AND THROUGH THE AREA LATE WEDNESDAY NIGHT INTO THURSDAY
EVENING. WIDESPREAD RAINFALL CHANCES WILL BEGIN TO INCREASE ACROSS
THE NORTHERN CWA ON WEDNESDAY AND WEDNESDAY NIGHT AHEAD OF THE
FRONT. THEN ACROSS THE ENTIRE AREA ON THURSDAY AS THE FRONT PASSES
THROUGH THE AREA. THE BETTER SHEAR AND UPPER LEVEL SUPPORT WILL
REMAIN TO THE NORTH OF THE AREA WHERE THE SEVERE WEATHER POTENTIAL
SHOULD REMAIN. SOME CONVECTION MAY LINGER ACROSS THE SOUTHERN CWA
THROUGH THURSDAY NIGHT...BUT BY THE LARGE PART MOST OF THE
CONVECTION SHOULD PUSH SOUTH OF THE AREA THURSDAY EVENING. THE GFS
STILL REMAINS SLIGHTLY SLOWER THAN THE ECMWF FOR THE TIMING OF
THIS SYSTEM AND HAVE CONTINUED TO FOLLOW MORE IN LINE WITH THE
MORE PROGRESSIVE ECMWF SOLUTION WITH REGARDS TO THE TIMING OF THIS
SYSTEM.

NORTHWEST FLOW ALOFT AND COOLER CONDITIONS WILL THEN SPREAD INTO
THE AREA BEHIND THE FRONT FRIDAY INTO THE WEEKEND. MAY HAVE TO
WATCH FOR AN UPPER LEVEL DISTURBANCE TRYING TO OVERRIDE THE
NORTHWEST FLOW INTO THE AREA SATURDAY NIGHT INTO SUNDAY...BUT IT
WILL BE HARD TO PINPOINT THE EXACT TRACK AND TIMING OF THIS
DISTURBANCE AT THIS TIME AS THIS WILL BE MORE OF A MESOSCALE
ISSUE.

WISE

&&

AVIATION...

FOR THE 18Z TAFS...

OCCASIONALLY GUSTY SOUTHWEST FLOW CONTINUES ACROSS THE AREA
TODAY...WITH A SOME SCATTERED SHRA/TSRA ACTIVITY OVER CENTRAL
MO THUS FAR THIS MORNING. COULD SEE SOME ACTIVITY WORK INTO KBBG
THIS AFTERNOON...BUT CURRENTLY BELIEVE THAT KSGF AND KJLN WILL
LIKELY REMAIN DRY. ANTICIPATE SEEING A LOSS OF DIURNAL CU THIS
EVENING...ALONG WITH MUCH OF THE SHRA ACTIVITY. BY EARLY TUESDAY
MORNING...GUIDANCE IS SUGGESTIVE OF VFR TO PERHAPS MVFR STRATUS
DEVELOPING ONCE AGAIN...THOUGH NOT TO THE DEGREE OF THIS MORNING.
ONLY OTHER CONCERN AT THIS TIME IS WITH LLWS AT KJLN...WHICH WILL
LIKELY BE ON THE EASTERN PERIPHERY OF AN OVERNIGHT LOW LEVEL JET.

BOXELL

&&

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

$$


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