Severe Thunderstorm Warning 81, NWS Springfield, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
346 AM CDT THU MAY 20 2004

.DISCUSSION...
EARLY THIS MORNING WATER VAPOR IMAGERY SHOWED AN UPPER LEVEL RIDGE
BUILDING INTO THE OZARKS REGION.  AN UPPER DISTURBANCE ON THE
WESTERN PERIPHERY OF THIS RIDGE TOUCHED OFF SOME SHORT-LIVED
CONVECTION ACROSS THE TEXAS PANHANDLE DURING THE EVENING HOURS.
FORECAST CONCERN IS WHETHER OR NOT THIS FEATURE WILL BRING STORMS TO
CENTRAL MISSOURI TODAY.  THE UPPER DISTURBANCE WILL TRACK UP AND
OVER THE MAIN RIDGE...REACHING WESTERN IOWA BY MIDDAY.  THE ETA
BREAKS OUT SOME PRECIPITATION ACROSS MY FAR NORTHERN COUNTIES
BETWEEN 15Z AND 18Z.  THE ATMOSPHERE LOOKS PLENTY UNSTABLE FOR
CONVECTION TODAY(CAPES 2000 TO 4000 J/KG) BUT WARM TEMPERATURES
ALOFT ARE EXPECTED INHIBIT CONVECTIVE DEVELOPMENT.  MODIFIED MESOETA
SOUNDING ACROSS CENTRAL MISSOURI YIELDS CINS IN EXCESS OF 100 J/KG
WHEN USING THE MEAN TEMPERATURE METHOD OF LIFTING.  IN
ADDITION...700 MB TEMPERATURES ARE PROGGED TO BE 11 DEG C.  IF
STORMS DO DEVELOP...CURRENT THINKING IS THEY WOULD FIRE FURTHER NORTH
ACROSS SOUTHERN IOWA WHERE THE CAP BECOMES WEAKER.

NEXT CONCERN IS WITH TEMPERATURES THE NEXT FEW DAYS.  PREVIOUS
FORECAST HAD A GOOD HANDLE ON THIS SO I MADE ONLY A FEW MINOR TWEAKS
TO THE TEMPERATURE GRIDS.  THE AIRMASS ACROSS THE REGION HAD WARMED
GREATLY FROM YESTERDAY...AS 850MB TEMPERATURES INCREASED FROM 16 DEG
C AT 12Z WED...TO 23 DEG C AT 00Z THU. DAILY RECORD TEMPERATURES ARE
IN THE LOW 90S...AND THESE VALUES MAY BE APPROACHED FOR FAVORED
LOCATIONS WEST AND NORTH OF THE OZARKS PLATEAU.  MOS GUIDANCE PROGS
UPPER 80S TO AROUND 90 ACROSS MUCH OF THE REGION WHICH LOOKS
REASONABLE. WITH DEWPOINT VALUES IN THE UPPER 60S TO AROUND 70
TODAY...HEAT INDICES WILL GET INTERESTING THIS AFTERNOON AS VALUES
MAY APPROACH THE MIDDLE 90S FROM EASTERN KANSAS INTO WEST-CENTRAL
AND CENTRAL MISSOURI. 850 MB TEMPERATURES COOL A BIT INTO THE
WEEKEND...BUT HIGHS ARE STILL EXPECTED TO TOP OUT IN THE MIDDLE AND
UPPER 80S FRIDAY THROUGH SUNDAY.

DRY WEATHER LOOKS TO PERSIST FRIDAY AND SATURDAY...AS THE AREA WILL
BE CAPPED WITH ANY BOUNDARIES WELL TO THE NORTH. THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS WILL ARRIVE ON SUNDAY...AS AN UPPER SYSTEM
TO THE NORTH DRAGS A WEAK FRONT INTO THE OZARKS. 30 POPS ACCOUNT
FOR THIS IN THE GRIDS.  FOR THE REMAINDER OF THE EXTENDED...HARD TO
PINPOINT ANY PERIOD WITH A HIGH LIKELIHOOD OF RAINFALL AS ALL OF THE
SIGNIFICANT UPPER LEVEL FEATURES STAY WELL NORTH OF THE OZARKS.  THE
GFS HINTS AT A WEAK BOUNDARY STALLING ACROSS SOUTHERN MISSOURI
TUESDAY NIGHT INTO WEDNESDAY...FOR NOW IVE GOT 20 POPS IN THE GRIDS
TO ACCOUNT FOR THIS.

SAW

&&

.AVIATION...
LOW LEVEL JET HAS DEVELOPED OVER AREAS WEST OF SPRINGFIELD OVERNIGHT
IN RESPONSE TO LEE TROUGH OVER WESTERN KANSAS AND EASTERN COLORADO.
WILL CONTINUE TO CARRY LOW LEVEL WIND SHEAR IN TAF SITES AND WESTERN
TWEB ROUTES UNTIL 14Z. WOULDT BE SURPRISED TO SEE A LITTLE LIGHT FOG
EAST OF SPRINGFIELD BEFORE SUNRISE WHERE DEWPOINT SPREADS ARE ONE TO
TWO DEGREES AND WINDS ARE 5 KTS OR LESS. SURFACE WINDS HAVE KEPT
BOUNDARY LAYER WELL MIXED OVERNIGHT WEST OF SPRINGFIELD...SO WILL
CONTINUE VFR VISIBILITY. WILL ONLY HAVE SCATTERED HIGH CLOUDS
STREAMING OVER THE REGION AROUND NORTH SIDE OF UPPER RIDGE CENTERED
OVER EASTERN TEXAS. MAY SEE A FEW AFTERNOON CUMULUS OVER NORTHERN
TWEB ROUTES BUT GENERALLY VFR CEILINGS ARE EXPECTED.

TERRY

&&

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

WFO SGF

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SPRINGFIELD MO
600 AM CDT THU MAY 20 2004

KSZ073-097-101-MOZ055>058-066>071-077>083-088>098-101>106-201800-
BARRY-BARTON-BENTON-BOURBON-CAMDEN-CEDAR-CHEROKEE-CHRISTIAN-CRAWFORD-
DADE-DALLAS-DENT-DOUGLAS-GREENE-HICKORY-HOWELL-JASPER-LACLEDE-
LAWRENCE-MARIES-MCDONALD-MILLER-MORGAN-NEWTON-OREGON-OZARK-PHELPS-
POLK-PULASKI-SHANNON-ST. CLAIR-STONE-TANEY-TEXAS-VERNON-WEBSTER-
WRIGHT-
INCLUDING THE CITIES OF...AVA...BOLIVAR...BRANSON...CAMDENTON...
FORT LEONARD WOOD...FORT SCOTT...HOUSTON...JOPLIN...LEBANON...
MONETT...MOUNT VERNON...NEOSHO...NEVADA...OSAGE BEACH...OZARK...
PITTSBURG...ROLLA...SPRINGFIELD...STOCKTON AND WEST PLAINS.
600 AM CDT THU MAY 20 2004

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

.DAY ONE...TODAY AND TONIGHT.

  WEATHER HAZARDS EXPECTED:

  ISOLATED THUNDERSTORMS WITH THE POTENTIAL TO PRODUCE HAIL TO THE
  SIZE OF NICKELS AND WIND GUSTS TO 60 MPH.

  AREAS AFFECTED AND TIMING:

  LOCATIONS GENERALLY ALONG AND NORTH OF A LAMAR TO SALEM LINE
  THROUGH THIS AFTERNOON.

  DISCUSSION:

  WEAK UPPER LEVEL DISTURBANCES WILL INTERACT WITH AN UNSTABLE
  AIRMASS ACROSS THE REGION TODAY...ALLOWING THUNDERSTORMS TO
  DEVELOP OVER LOCATIONS GENERALLY NORTH OF INTERSTATE 44.  A WARM
  LAYER OF AIR ALOFT IS EXPECTED TO KEEP THE ACTIVITY ISOLATED IN
  NATURE. HOWEVER...ANY STORMS WHICH DO FORM HAVE THE POTENTIAL TO
  PRODUCE LARGE HAIL AND GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

  A FRONTAL SYSTEM WILL PUSH INTO THE REGION ON SUNDAY...BRINGING A
  CHANCE OF THUNDERSTORMS TO SOUTHEAST KANSAS AND THE MISSOURI
  OZARKS.

.SPOTTER INFORMATION STATEMENT...

  SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT...AS
  THUNDERSTORMS ARE EXPECTED TO BE ISOLATED.

SAW