Severe Thunderstorm Warning 258, NWS Springfield, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
250 AM CDT WED MAY 14 2003

SCATTERED CONVECTION CONTINUED EARLY WEDNESDAY MORNING ACROSS SOUTH
CENTRAL MISSOURI. RUC MODEL ANALYSIS AND PROFILER DATA SUGGEST A
SUBTLE MID LEVEL SHORTWAVE WAS SUPPORTING THIS ACTIVITY.  OTHERWISE
CONVECTION WAS FOCUSED ACROSS CENTRAL OKLAHOMA WHERE THE LOW LEVEL
JET WAS INTERSECTING THE SURFACE WARM FRONT.

A PROGRESSIVE BUT RATHER COMPLEX PATTERN WILL CONTINUE INTO THE
WEEKEND.  A SERIES OF SHORTWAVE TROUGHS AND MEANDERING SURFACE
BOUNDARIES WILL LEAD TO SOME UNCERTAINTY TO TIMING AND COVERAGE OF
CONVECTION.

A SURFACE FRONT WILL SAG SOUTH TODAY IN THE WAKE OF THE MINOR
SHORTWAVE TROUGH PUSHING ACROSS IOWA THIS MORNING...AND IN ADVANCE
OF THE UPPER LOW DROPPING SOUTH OF THE NORTHERN PLAINS. THIS FRONT
WILL MAY MAKE IT INTO SOUTHERN MISSOURI BY MID AFTERNOON...ALTHOUGH
THERE IS SOME QUESTION IF IT WILL MAKE IT THIS FAR SOUTH. IT MAY
TAKE THE PASSAGE OF THE UPPER LOW TO GET THE FRONT ALL THE WAY
THROUGH. INSTABILITY WILL BE DETERMINED TO A GREAT DEGREE BY
RESIDUAL CONVECTIVE DEBRIS...BUT IT APPEARS AMPLE SUNSHINE WILL
DEVELOP TO RESULT IN MODERATE INSTABILITY ALONG THE FRONT THIS
AFTERNOON.  WIND FIELDS WILL BE RELATIVELY WEAK BUT WEAK CONVERGENCE
ALONG THE FRONT...DESCENT DIRECTIONAL SHEAR...AND MODERATELY STEEP
LAPSE RATES SHOULD BE ENOUGH TO IGNITE SCATTERED CONVECTION. GIVEN
THE WEAK WIND FIELD THE PRIMARY SEVERE WEATHER THREAT WILL BE LARGE
HAIL ALONG WITH SOME LOCALIZED DAMAGING WINDS. GIVEN THE RAINFALL
THAT OCCURRED TUESDAY AND NEAR SATURATED SOIL CONDITIONS...SOME
LOCALIZED FLOODING COULD DEVELOP. EXPECT MAJORITY OF CONVECTION TO
DIMINISH THIS EVENING WITH LOSS OF DAY TIME HEATING.

AS THE UPPER LOW TO THE NORTH DROPS INTO THE OHIO RIVER VALLEY THE
SURFACE FRONT WILL SAG ACROSS FAR SOUTHERN MISSOURI THURSDAY.  THE
ETA DOES NOT PUSH THE FRONT SOUTH OF THE MISSOURI/ARKANSAS BORDER
UNTIL LATE AFTERNOON THURSDAY. THIS SCENARIO LOOKS REASONABLE GIVEN
THE PASSAGE OF THE UPPER LOW TO THE EAST. WITH THAT SAID I WILL
INTRODUCE RAIN CHANCES TO FAR SOUTHERN MISSOURI THURSDAY AFTERNOON
WHERE INSTABILITY AXIS DEVELOPS ALONG THE SURFACE BOUNDARY.
CONVECTION WILL REFIRE ACROSS SOUTHERN PLAINS THURSDAY NIGHT A LOW
LEVEL JET STRENGTHENS AHEAD OF THE NEXT SYSTEM NOW OFF OF THE
CALIFORNIA COAST.

MODELS DIFFER ON THE NORTHWARD EXTENT OF CONVECTION FRIDAY WITH THE
GFS THE FURTHEREST NORTH. SOUTHERN MISSOURI AND SOUTHEAST KANSAS MAY
GET BRUSHED BY A MORNING CONVECTIVE COMPLEX THAT WILL SLIDE EAST OUT
OF THE SOUTHERN PLAINS.  ADDITIONAL DEVELOPMENT WILL THEN TAKE PLACE
FRIDAY AFTERNOON AND EVENING AS THE TROUGH PUSHES INTO THE PLAINS.

IN THE EXTENDED (DAYS 4 THROUGH 7)...VARYING SOLUTIONS ON PLACEMENT
OF THE UPPER LEVEL SHORTWAVE BY THE AVN AND ETA MODELS CAUSES
CONCERN. THE ETA DROPS THE UPPER LOW FURTHER SOUTH THAN THE AVN
RESULTING IN PLACEMENT OF AN MCS OVERNIGHT FRIDAY INTO SATURDAY OVER
CENTRAL OKLAHOMA AND ARKANSAS... RATHER THAN ALONG THE
MISSOURI/ARKANSAS BORDER AS SHOWN BY THE AVN. THE SOUTHERN FEW TIERS
OF COUNTIES COULD SEE ANYWHERE FROM A QUARTER OF AN INCH TO A
FEW INCHES OF PRECIPITATION DEPENDING ON THE TRACK OF THE UPPER
LEVEL LOW. PRECIPITATION SHOULD END SATURDAY EVENING AS THE UPPER
LOW SWINGS BY. PRECIPITATION IS NOT OUT OF THE QUESTION SUNDAY AND
MONDAY DEPENDING UPON THE LOCATION OF A SURFACE FRONT BY THAT TIME.
HOWEVER HAVE LEFT SUNDAY AND MONDAY DRY FOR NOW UNTIL BETTER FRONTAL
PLACEMENT CAN BE DETERMINED. HAVE BUMPED TEMPERATURES UP SLIGHTLY
ABOVE NORMAL SUNDAY THROUGH TUESDAY AS HIGH PRESSURE BUILDS
OVERHEAD. THE NEXT SURFACE FRONT APPROACHES THE AREA ON TUESDAY AND
WAS ALREADY REFLECTED IN THE FORECAST SO FEW CHANGES WERE MADE.

FORECAST GRIDS ARE OUT.

.SGF...
MO...NONE.
KS...NONE.

FOSTER/STOFLET

KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-141100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SPRINGFIELD MO
716 PM CDT TUE MAY 13 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MISSOURI OZARKS AND EXTREME
SOUTHEAST KANSAS.

.DAY ONE...TONIGHT.

WEATHER HAZARDS EXPECTED:

THUNDERSTORMS CONTAINING HEAVY RAIN AND HAIL UP TO THE SIZE OF
NICKELS.

AREAS AFFECTED AND TIMING:

A COMPLEX OF SHOWERS AND THUNDERSTORMS WILL SPREAD OVER EXTREME
SOUTHEAST KANSAS AND MISSOURI OZARKS AFTER 1000 PM.

DISCUSSION:

A DEVELOPING LOW LEVEL JET WILL COMBINE WITH AN APPROACHING COLD
FRONT TO INITIATE A COMPLEX OF SHOWERS AND THUNDERSTORMS.  THIS
ACTIVITY IS EXPECTED TO AFFECT MUCH OF THE REGION LATE TONIGHT...AND
CONTINUE INTO THE EARLY MORNING HOURS ACROSS SOUTHERN MISSOURI.  DUE
TO THE LACK OF SURFACE BASED INSTABILITY...WIDESPREAD SEVERE
THUNDERSTORMS ARE NOT LIKELY.  HOWEVER...BECAUSE WET BULB ZERO
TEMPERATURE LEVELS ACROSS THE OZARKS ARE RELATIVELY LOW...SOME OF
THESE STORMS MAY CONTAIN HAIL UP TO THE SIZE OF NICKELS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

ISOLATED SEVERE STORMS WILL BE POSSIBLE WEDNESDAY AS A COLD FRONT
BECOMES NEARLY STATIONARY ACROSS SOUTHERN MISSOURI.  LARGE HAIL WILL
AGAIN BE THE PRIMARY THREAT.

THUNDERSTORMS WILL RETURN TO THE AREA AGAIN LATE IN THE WEEK
AHEAD OF THE NEXT SYSTEM.  ISOLATED SEVERE STORMS AND LOCALLY
HEAVY RAIN WILL BE POSSIBLE FRIDAY INTO EARLY SATURDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

  SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

&&

THIS PRODUCT IS NOW AVAILABLE IN GRAPHICAL FORMAT...ALONG WITH OTHER
WEATHER...HYDROLOGICAL AND CLIMATE INFORMATION...AT
HTTP://WWW.CRH.NOAA.GOV/SGF

CRAMER