Sunday, June 27, 2010

Area Forecast Discussion - South Central/Southwest Missouri

FXUS63 KSGF 272002
NATIONAL WEATHER SERVICE SPRINGFIELD MO
302 PM CDT SUN JUN 27 2010

DISCUSSION...
/ISSUED 301 PM CDT SUN JUN 27 2010/

FORECAST HIGHLIGHTS INCLUDE RAIN CHANCES TONIGHT AND MONDAY...
DRIER AND COOLER CONDITIONS MUCH OF THE UPCOMING WEEK.

NEAR TERM...COLD FRONT...DENOTED BY A SFC WIND SHIFT...IS JUST NW
OF THE CWA AT THIS HOUR. THIS FEATURE WILL MAKE LITTLE PROGRESS
EAST HEADING INTO THIS EVENING. AIRMASS AHEAD OF THE FRONT IS
DEFINITELY WARM AND MOIST. MLCAPE IS GREATER THAN 3000 J/KG WITH
NO CAP. WAT VAP IMAGERY AND 500MB VORTICITY PLOT FROM RECENT RUC
INITIALIZATIONS INDICATES THAT A WEAK WAVE IS MAKING PROGRESS
EASTWARD INTO E KS. AS THIS FEATURE OVERTAKES THE SFC FRONT IN THE
NEXT 3 TO 6 HOURS...EXPECT AN INCREASE IN COVERAGE OF SHRA/TSRA.
WIND SHEAR REMAINS QUITE WEAK...THUS STORM ORGANIZATION WILL SIDE
WITH MULTICELLULAR. SBCAPE AND MLCAPE ARE CERTAINLY SUPPORTIVE OF
STRONG UPDRAFTS...THOUGH GIVEN ONLY BROAD LOW LEVEL CONVERGENCE
ANY RISK FOR SEVERE WILL BE LOCALIZED AND ON THE ORDER OF FEW/FAR
BETWEEN. OVERALL EXPECT STORMS CAPABLE OF 45 MPH WIND GUSTS...
SMALL HAIL...FREQ LIGHTNING AND LOCALLY HEAVY RAINFALL.

SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...

PRIMARY FORECAST CHALLENGE IS TIMING THE EXIT OF WHAT WILL BE A
RATHER SLOW MOVING FRONT AND GRADUAL AIRMASS CHANGE. WEAK
FORCING AND LOW LEVEL CONVERGENCE WILL LINGER ACROSS SOUTHERN MO
INTO MONDAY MORNING...THOUGH THIS SHOULD SHIFT INTO N ARK BY THE
AFTERNOON. LINGERING CLOUDS AND SCT SHRA/TSRA WILL LEND TO COOLER
CONDITIONS WITH HIGHS IN THE MID/UPPER 80S. GRADUAL AIRMASS CHANGE
WILL LEVEL OUT TUESDAY WITH QUIET...DRIER AND COOLER CONDITIONS. A
MOST WELCOME CHANGE TO WHAT HAS BEEN A RATHER WARM JUNE.

LONG TERM (WEDNESDAY THROUGH SUNDAY)...

RIDGE OF HIGH PRESSURE ALOFT WILL DOMINATE OUR WEATHER REGIME. DRY
WITH SEASONABLY WARM TEMPERATURES ARE ON TAP FOR MUCH OF THE
PERIOD. AS THE RIDGE AXIS SHIFTS TO THE EAST TOWARDS THE HOLIDAY
WEEKEND...THERE WILL BE A GRADUAL INCREASE IN TEMPS AND HUMIDITY...
THOUGH NOTHING UNUSUAL FOR THE TIME OF YEAR. THERE ARE DIFFERENCES
IN THE MED RANGE MODEL OUTPUT HEADING INTO NEXT WEEKEND. WILL NEED
TO KEEP AN EYE ON THE BEHAVIOR OF TD ALEX...CURRENTLY OVER THE
YUCATAN. OFFICIAL NHC GUIDANCE HAS THIS STORM SLOWLY MOVING WNW
DURING THE WEEK...TURNING TO THE WEST INTO OLD MEXICO BY FRIDAY.
HOWEVER...THERE IS CONSIDERABLE SPREAD WITH THE EVENTUAL TRACK OF
THIS FEATURE AND THE SPEED WITH WHICH IT WILL MOVE. THERE ARE
MODEL SOLUTIONS OUT THERE THAT TAKE THIS FEATURE DUE NORTH INTO
THE MIDWEST BY FRIDAY (GFS AND GEM)...WHILE OTHER MODELS KEEP THIS
FEATURE CONFINED TO OLD MEXICO. MUCH WILL DEPEND ON HOW THE UPPER
RIDGE ALOFT BEHAVES...IN PARTICULAR ITS POSITION AND STRENGTH. AM
NOT RULING OUT ANY SOLUTIONS AT THIS POINT. KEEP A WARY EYE ON
ALEX AS WE HEAD INTO THIS WEEK.

GAGAN

&&

AVIATION...

A COLD FRONT ACROSS THE PLAINS WILL GRADUALLY TRACK SOUTHEAST
INTO THE OZARKS LATE THIS AFTERNOON INTO TONIGHT. WITH THE
APPROACH OF THE FRONT...SURFACE WINDS WILL GRADUALLY WEAKEN AND
SHIFT TO THE NORTH BEHIND THE FRONT. THE AIRMASS REMAINS UNSTABLE
AHEAD OF THE FRONT WITH ISOLATED THUNDERSTORMS POSSIBLE THROUGH
THIS AFTERNOON WITH SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP
CLOSER TO THE FRONT. NEAR THE STRONGER THUNDERSTORMS...VISIBILITIES
WILL LIKELY BE REDUCED TO IFR DUE TO THE MOISTURE CONTENT OF THE
AIRMASS IN PLACE.

ANGLE

&&

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

$$

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