Severe Thunderstorm Warning 142, NWS St. Louis, MO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
441 PM CDT TUE JUN 8 1999

MAIN FCST PROBLEM: PCPN CHCS AGAIN.

RATHER HURRIED THIS AFTN WITH ANALYSIS OF UPPER AIR AND MODELS WHILE
DOING DOUBLE DUTY ON SHORT TERM AND AVIATION EVENTS. QUICK GLANCE OF
MODEL INITIALIZATION WITH RESPECT TO WV IMAGERY THIS AM SHOWED ALL
MODELS WITH SOME DEGREE OF ERROR WITH VORT CNTR THAT WAS OVER XTRM
NERN KS...AS WELL AS WEAK SHRT WVS RIDING ON WSTRN SIDE OF UPPER
RIDGE. MODELS LOOKED REASONABLY WELL WITH STRONGER UPPER LVL
FEATURES.

THE 12Z MON NGM RUN HAD THE BEST RATE OF MOVEMENT OF NERN KS/WRN MO
VORT MAX. ADJUSTMENT OF THE 12Z MON NGM RUN...BY PLACING THE VORT
CNTR EWD FROM ITS ORIG POSTN...RESULTED IN A VORT TRACK THAT NAILED
THE POSTN WELL. THE 12Z RUN OF THE RUC THIS MORNING HAD GOOD HANDLE
ON VORT CNTR AS WELL.

AFT LOOKING AT ALL THREE MODELS FROM TODAYS 12Z RUN...THE ETA AND AVN
HAD THE BEST HANDLE WITH VORT CNTR OVER NERN KS/NRN MO AS COMPARED TO
THE NGM...HOWEVER WERE A BIT TO FAR NORTH.

MANUAL ANALYSIS OF 500MB INDICATED SVRL COLD TROFS AND WK SHRT WVS
XTNDG FROM WRN OK TO WRN TX. MAIN UPPER JET WAS WELL TO THE NW OF THE
PLNS...SO MOVMNT OF UPPR FEATURES OVER THE OZARKS WILL BE SLOW AT
BEST. A CLOSED 500MB LOW WAS JUST WEST OF FL WITH 12HR HT FALLS
INDICATG A SLOW NWD PROGRESSION.

I AM CONFIDENT WITH THE ETA AND AVN SOLN WITH VORT CNTR...ALTHOUGH
WITH A SWD ADJUSTMENT...THIS SYSTEM WILL CONT TO PULL NEWD TO ERN IA
TONIGHT...UVV ASSOC WITH THIS FEATURE HAS ALREADY DECRSD OVER THE NRN
MOST COUNTIES SINCE TCU AND TSTMS HAVE DIMINISHED DURG THE LAST THREE
HRS. MOST ACTION WAS OVR NRN...NERN...AND ERN MO. DIURNAL HTG OF
UNSTABLE AIRMASS WAS CAUSING CU AND SOME TCU...WITH SOME BRIEF ISOLD
TSTMS...BUT RE-DVLPMNT WAS ALMOST NON-EXISTENT AS COMPARED TO
YESTERDAY. BELIEVE THAT CU AND TCU ENTRAINED RELATIVELY DRIER AIR AT
850MBS...AS COMPARED TO YESTERDAY...AND RESULTED IN THE SHORT LIVED
CLOUD FEATURES.

WILL KEEP HIGHEST POPS GOING OVER THEN NRN COUNTIES...WHERE INSTAB IS
GREATEST AND LOWER POPS ELSEWHERE. ALL THESE AREAS WILL HAVE POPS
UNTIL SUNSET THIS EVENING.

MODELS DEPICT A WK SHRT WV IN SW FLOW FRM OK TO TX THRU THE PERIOD.
I CAN SEE THIS SHRT WV IN THE 500MB ANALYSIS AND WV IMAGERY...BUT
THERE WAS NO MID LVL CLDINESS ASSOC WITH THIS SHRT WV ON EITHER IR OR
VIS SAT IMAGERY. BELIEVE THIS SHRT WV WILL NOT CAUSE PCPN TONIGHT BUT
COULD AID IN ISOLD TO WIDLY SCT TSTMS OVER THE CWFA ON WED.

BEYOND WED HOWEVER...I AM NOT CONFIDENT WITH MODELS HANDLING OF WK
UPPER FEATURES. EVEN THOUGH HUMID AND UNSTABLE AIR MASS WILL REMAIN
IN PLACE...WILL LEAVE OUT MENTION OF PCPN FOR WED NGT AND THURS.

MRF BRINGS TWO FEATURES TOGETHER FOR THIS WEEKEND. FIRST IN THE FORM
OF A WK COLD FNT THAT WILL DRAPE ACROSS THE CNTRL PLNS BY SUN.
SECONDLY...A 500MB LOW THAT WAS OVER THE GULF OF MEXICO WILL PARTLY
MOVE NWD INTO THE SRN PLNS. THIS LOW WILL DEEPEN A LAYER OF TROPICAL
MSTR INTO THE REGION...THIS MSTR WILL CONVERGE INTO THE COLD FNT.
THIS WILL RESULT IN TSTMS OVER THE OZARK REGION SAT AND SUN.

WENT WITH FWC GUID TEMPS FOR LOWS TNGT AND WED NGT AND HIGHS ON WED.
RAISED FWC HIGHS ON THURS. HAD TO UP POPS FOR THIS EVE.

CCF
SGF BB 067/088 067/088 067 122211
JLN BB 069/089 069/089 068 122211
UNO BB 067/087 067/087 068 122211
VIH BB 067/088 067/088 067 123211

D.STEINMETZ

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MISSOURI
558 PM CDT TUE JUN 08 1999

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1251 PM    WASHINGTON                MO   1 INCH HAIL
06/08/99   FRANKLIN                       1 INCH HAIL REPORTED BY
                                          SEVERE WEATHER SPOTTER

0140 PM    2 W LIVELY GROVE          IL   .75 INCH HAIL
06/08/99   WASHINGTON

0250 PM    MAPLEWOOD                 MO   WIND DAMAGE
06/08/99   ST LOUIS                       FEW LARGE TREES DOWNED BY
                                          HIGH WINDS AND BLOCKING
                                          ROAD

0300 PM    ST LOUIS                  MO   WIND DAMAGE
06/08/99   ST LOUIS CITY                  WALL OF A BUILDING
                                          COLLAPSED DUE TO HIGH
                                          WINDS.  POWER LINES ALSO
                                          DOWNED

0303 PM    CAHOKIA                   IL   WIND DAMAGE
06/08/99   ST CLAIR                       HIGH WINDS DAMAGED THE
                                          ROOF ON A BUILDING AND
                                          DOWNED LARGE TREES

0340 PM    DITTMER                   MO   WIND DAMAGE
06/08/99   JEFFERSON                      POWER LINES DOWNED BY HIGH
                                          WINDS

0340 PM    WIND DAMAGE
06/08/99   MARION                         HIGH WINDS UPROOTED 4
                                          LARGE TREES AND DOWNED 2
                                          POWER POLES

...IN ADDITION...WIND DAMAGE WAS REPORTED IN SOUTHERN SECTIONS OF ST
LOUIS CITY...BUT TIME AND LOCATION ARE UNKNOWN...

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