Severe Thunderstorm Warning 60, NWS Springfield, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
227 PM CDT TUE APR 23 2002

LATEST SURFACE ANALYSIS SHOWS A RATHER COMPLEX SCENARIO ACROSS THE
PLAINS WITH COLD POOL/CONVECTIVE DEBRIS FROM MORNING MCS LEAVING
SEVERAL WELL DEFINED THERMAL BOUNDARIES TO OUR WEST AND SOUTH.
ACROSS WRN OK...STRONG MOISTURE FLUX HAS RESULTED IN 70F DEWPOINTS
AS FAR NORTH AS LAWTON ADJACENT TO ERLY FLOW WITH DRIZZLE AND TEMPS
AROUND 60. WATER VAPOR IMAGERY INDICATES SUBTROPICAL JET PLUME AND
ASSOCIATED CIRRUS BEGINNING TO ADVANCE NORTHEAST...AND WILL LIKELY
HELP TO INITIATE CONVECTION IN THAT REGION TOWARD SUNSET. AS THIS
ACTIVITY PUSHES EAST...LOW LEVEL JET WILL ONCE AGAIN INTENSIFY...
ALLOWING ELEVATED STORMS TO DEVELOP NORTHWARD INTO THE LEFTOVER COLD
POOL. THE GREATEST THREAT FOR SEVERE WEATHER IN MY CWA WILL BE
ACROSS WRN MO/SE KS AND THEN SRN MO...WITH LARGE HAIL BEING THE
PRIMARY THREAT GIVEN ELEVATED NATURE OF CONVECTION. IF ACTIVITY CAN
DEVELOP INTO A FORWARD PROPAGATING MCS...THEN WIND DAMAGE MAY BECOME
AN INCREASING THREAT GIVEN STRONG DRY AIR ENTRAINMENT AT MID
LEVELS...STRONG DEEP LAYER SHEAR...AND RELATIVELY DRY/ISOTHERMAL
LAYER BELOW CAP. WILL ADD SEVERE WORDING TO FORECAST ACROSS THESE
AREAS.

STRONG SURFACE COLD FRONT WILL SLAM THROUGH THE CWA TOMORROW
(MORNING/EARLY AFTERNOON)...WHICH MAY BE THE FOCUS FOR ANOTHER ROUND
OF SEVERE CONVECTION. SIMILAR TO SUNDAY...CHANCE FOR REDEVELOPMENT
WILL DEPEND HIGHLY ON TIMING OF SURFACE FRONT AND AIRMASS RECOVERY.
GIVEN CONSISTENCY OF ETA/AVN SOLUTIONS...THINK CHANCES FOR SEVERE
STORMS TOMORROW ARE SLIM GIVEN PROGGED PROGRESSION OF SURFACE FRONT
AND CONVECTIVE DEBRIS FROM TONIGHTS ACTIVITY. IF SURFACE FRONT CAN
SLOW DOWN ENOUGH...THEN A DAMAGING WIND THREAT EXISTS ACROSS CENTRAL
AND SOUTH CENTRAL MISSOURI.  OTHERWISE...WILL PLAY TEMPERATURES
CLOSE TO NEW ETA MOS...BETWEEN VERY COLD MAV (60 FOR SGF) AND MUCH
WARMER FWC (77 FOR SGF).  OTHER CONCERN WILL BE GRADIENT WINDS
BEHIND COLD FRONT...WHICH COULD GUST TO 30 MPH FROM LATE MORNING
INTO EARLY AFTERNOON.

NEXT FORECAST PROBLEM WILL BE WITH MUCH COLDER/DRIER AIRMASS THAT
WILL BUILD IN FOR TOMORROW NIGHT AND THURSDAY. AMOUNT OF RAIN
TOMORROW COULD MEAN THE DIFFERENCE BETWEEN A POTENTIAL FROST OR
DENSE FOG. GIVEN LIKELIHOOD OF RAINFALL TONIGHT AND TOMORROW...WILL
ADD MENTION OF PATCHY FOG FOR TOMORROW NIGHT BUT AREAS THAT DO NOT
RECEIVE PRECIP IN THE NEXT 24 HOURS WILL HAVE TO BE MONITORED FOR
FROST CONCERNS TOMORROW NIGHT AS CLEAR SKIES AND MODIFIED CANADIAN
HIGH BUILD IN.

SURFACE HIGH WILL REMAIN IN PLACE FOR THURSDAY AND FRIDAY...WITH
ANOTHER CHILLY NIGHT THURSDAY. GOING TEMPERATURE FORECAST LOOKS
KOSHER FOR THIS PERIOD. RIDGE AXIS WILL MOVE EAST ON FRIDAY AS NEXT
SYSTEM DEVELOPS OVER ERN CO. STRONG SRLY FLOW SHOULD RETURN TO THE
AREA BY FRIDAY AFTERNOON AS INDICATED BY THE AVN SFC-850MB
PRESSURE/HEIGHT FIELDS. FMR/MEX GUIDANCE WITH HIGHS IN THE UPPER 50S
SEEMS VERY UNLIKELY GIVEN UNDERPLAY OF WARM ADVECTION THAT SHOULD
DEVELOP IN RESPONSE TO SURFACE/UPPER FLOW PATTERN. THEREFORE HAVE
GONE CONSIDERABLY ABOVE GUIDANCE (65-70).

LARGE DISAGREEMENTS REMAIN IN THE EXTENDED...BUT CONTINUE TO FOLLOW
MORE CONSISTENT ECMWF WHICH HAS SHOWN EXCELLENT SKILL OF LATE. THIS
SOLUTION DEVELOPS A NEAR REX BLOCK ACROSS THE ERN PACIFIC/WRN US
WITH VERY STRONG AMPLIFIED RIDGE/TROUGH COUPLET. NEXT SYSTEM WILL
BRING ANOTHER ROUND OR TWO OF CONVECTION TO THE AREA LATE FRIDAY
THROUGH SATURDAY...WITH A LARGE UNCERTAINTY THEREAFTER. WILL LEAVE
FORECAST DRY FOR NOW SUN-TUES...BUT WEAKNESS IN SFC PRESSURE FIELD
AND SOUTHWEST FLOW ALOFT AHEAD OF WESTERN TROUGH COULD BRING SPELLS
OF SHOWERS ON MONDAY AND TUESDAY. TEMPERATURES LOOK CLOSE TO CLIMO.

FINALIZED ISC GRIDS OUT SHORTLY.

BOOKBINDER