Severe Thunderstorm Warning 207, NWS Kansas City, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
155 PM CDT WED JUL 26 2000

FCST CHALLENGES: LOCATION AND TIMING OF CONVECTIVE INITIATION

FNTL BNDRY RMNS NORTH OF FCWA THIS AFTN.  ALL SIGNS POINT FOR ANOTHER
ROUND OF CONVECTION TONIGHT AS TAIL OF UPR MIDWEST S/W ACTIVATES
BOOSTS WEAK LLVL FORCING.  AVN INDICATES LAPSE RATES THAT WL SUPPORT
SVR CONVECTION OVR AREA TONIGHT THROUGH THU NITE.  META A LTL MORE
CONSERVATIVE...INDICATING RISK OF SVR WL HOLD OFF UNTIL THU.  THETAE
RDG DELINEATING INSTABILITY AXIS...PROGD BY AVN TO PUSH INTO NRN PART
OF CWA THIS EVENING WHILE...NGM AND META SHOW LESS SWD PUSH.  BOTH AVN
AND RUC INIT CONVECTION THEN PUSH ACTVTY INTO NWRN PART OF CWA THIS
EVENING. NGM AND ETA BOTH SHOWING LESS DEVELOPMENT ACRS CWA THIS
EVENING...BUT BOTH INDICATE CONVECTION BRUSHING NE PART OF CWA BY
12Z THU.  BTR CHC OF STMS WL OCCUR ON THU INTO FRI AS FNTL BNDRY
WL BE STRETCHED ACRS FCWA.  0-6KM SHEAR VECTORS AND H7-H5 LAPSE
RATES BOTH SUPPORT SVR CONVECTION ESPECIALLY ON THU AND THU NITE.
WND PROFILES NOT SHOWING A LOT OF DIRECTIONAL SHEAR TO SUPPORT
TORNADIC ACTIVITY THO...LO LVL BACKING ALNG FNT CULD PROVIDE ENUF
TORQUE TO PRODUCE ISO TORNADOES. FLOW WEAKENS ON FRI THUS...SVR THREAT
LIKELY WL DIMINISH.

TEMPS WL BE TRICKY AS...CONVECTIVE DEBRIS AND EVAP COOLING MAY KEEP
TEMPS A LTL COOLER TMRW BUT...COMPRESSIONAL WARMING ALNG THE FNT MAY
OFFSET.  MORE CLDS AND PRECIP ARND ON FRI THUS...COOLER TEMPS PROGD
BY GUID VALUES LOOK OKAY.  BNDRY SAGS SWD TWD THE RED RIVER VALLEY
BY SUNDAY...ALLOWING SFC HI PRES TO DOMINATE OVR LATTER PART OF
WKEND.  CANT RULE OUT CHC OF STMS ACRS SRN ZONES ON SAT AS...WITH
CYC FLOW ALOFT AND WEAK BNDRY STRETCHED ACRS SRN MO.

MEDIUM RNG MODELS KEEP UPR LVL TROF OVR AREA THRU EXTENDED PD
BUT...THEY ALL KEEP MOST OF CWA ON ANTICYC SHEAR SIDE.  WITH THAT IN
MIND...WL CTN DRY FCST IN THE SUN TO TUES TIME FRAME.  TEMPS MAY
MODERATE A LTL BUT...ENUF MOISTURE AND CU ARND TO KEEP TEMPS FRM
SKYROCKING MUCH ABV NORMAL.
PKG

.EAX...NONE

KSZ025-057-060-102>105-MOZ001>008-011>017-020>025-028>033-037>040-
043>046-053-054-271100-

HAZARDOUS WEATHER OUTLOOK...UPDATED TYPE AND TIMING OF THUNDERSTORM
THREAT
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
342 PM CDT WED JUL 26 2000

...SEVERE THUNDERSTORMS POSSIBLE TONIGHT ACROSS NORTHERN PORTIONS OF
THE OUTLOOK AREA...

FORECAST...SEVERE THUNDERSTORMS ARE POSSIBLE TONIGHT MAINLY ALONG
AND NORTH OF INTERSTATE 70. AN ISOLATED TORNADO IS ALSO POSSIBLE
ACROSS EXTREME NORTHERN MISSOURI THIS EVENING...MAINLY NORTH OF
ROUTE 36. HOWEVER THE PRIMARY THREATS ARE LARGE HAIL AND DAMAGING
WINDS. SPOTTER ACTIVATION MAY BE NEEDED TONIGHT.

THE THREAT OF STRONG THUNDERSTORMS IS EXPECTED PERIODICALLY THROUGH
EARLY SATURDAY WITH THE GREATEST THREAT THURSDAY AND FRIDAY NIGHTS.
A PERIOD OF VERY HEAVY RAINFALL IS ALSO POSSIBLE DURING THIS TIME
PERIOD.

DISCUSSION...A COLD FRONT IN IOWA AND NEBRASKA WILL CONTINUE TO
TRIGGER THUNDERSTORMS IN EASTERN NEBRASKA AND CENTRAL IOWA LATE THIS
AFTERNOON AND TONIGHT. THE STORMS ARE EXPECTED TO ENTER MISSOURI AND
EXTREME NORTHEAST KANSAS THIS EVENING. AS THE STORMS MOVE SOUTHEAST
ACROSS THE AREA...THEY WILL ENCOUNTER AN INCREASINGLY MORE STABLE
AIR MASS. AS A RESULT THE GREATEST THREAT OF SEVERE WEATHER IS ACROSS THE
COUNTIES ALONG THE IOWA BORDER. DUE TO A FAVORABLE WIND PROFILE...AN
ISOLATED TORNADO IS POSSIBLE THIS EVENING ACROSS EXTREME NORTHERN
MISSOURI...ALONG AND NORTH OF ROUTE 36. HOWEVER...DUE TO
UNSEASONABLY COLD AIR IN THE UPPER LEVELS OF THE ATMOSPHERE...LARGE
HAIL IS THE PRIMARY THREAT. DAMAGING WINDS ARE ALSO POSSIBLE. BY
MIDNIGHT...THE SEVERE WEATHER THREAT IS EXPECTED TO BE LIMITED TO
LARGE HAIL AND DAMAGING WINDS.

THE FRONT WILL REMAIN IN THE VICINITY OF THE OUTLOOK AREA THROUGH
FRIDAY...THUS PROVIDING ADDITIONAL THREATS OF SEVERE WEATHER THROUGH
EARLY SATURDAY.

DB