Severe Thunderstorm Warning 142, NWS Paducah, KY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
215 PM CDT FRI SEP 7 2001

MAIN FORECAST CHALLENGE THIS PACKAGE IS TIMING OF APPROCHING FRONT
AND ASSOC POPS.

12Z MODEL RUNS STILL INDICATE A SLOWER TREND WITH THE APPROACHING
SYSTEM...BRINGING IT THROUGH SUNDAY AND SUNDAY NIGHT INSTEAD OF ON
SATURDAY. THE PRIMARY REASON FOR THIS DIFFERENCE IS A CHANGE IN THE
UPPER-LEVEL PATTERN. THE UPPER-RIDGE OVER THE EAST COAST HAS PROVED
TO BE TOUGHER THAN EXPECTED AND IS FORCING ENERGY ROTATING THROUGH
THE DEVELOPING CENTRAL U.S. TROUGH TO TAKE MORE OF A NORTHERLY PATH.
THIS PATH WILL GENERALLY TAKE THIS SYSTEM (SFC/UPPER LOWS) TO THE
WEST OF THE FORECAST AREA THROUGH SATURDAY NIGHT. MODELS VERY
DIFFERENT IN THEIR TIMING OF THE FRONTAL PASSAGE. WILL COMPROMISE
BETWEEN AVN/ETA SOLUTIONS FOR TIMING OF FROPA AND POPS. AROUND
MIDDAY SUNDAY THE FRONT BEGINS ITS SLOW TREK ACROSS OUR CWA CAUSING
THE DEVELOPMENT OF WIDESPREAD PRECIPITATION.

IN THE MEANTIME...WITH LACK OF DYNAMICS FEEL THAT ONGOING CONVECTION
WILL BE MAINLY DIURNAL IN NATURE SO WILL ONLY MENTION EVENING RW/TRW
TONIGHT. PRECIPITABLE WATER VALUES STILL PUSHING 2 INCHES SO LOCALLY
HEAVY DOWNPOURS A GOOD BET BUT DECENT MOVEMENT OF STORMS SHOULD
PREVENT ANY SIGNIFICANT FLOODING PROBLEMS.

ON SATURDAY THE AVN ROTATES A SHORT-WAVE TROUGH AND SURFACE LOW
PRESSURE CENTER QUICKLY INTO WISCONSIN...WHILE THE WESTERN END OF
THE SURFACE TROUGH BEGINS TO SLOW DOWN DUE TO A SECONDARY SHORT WAVE
DIGGING SE TOWARD THE BASE OF THE MAIN UPPER TROUGH. AT THE SAME
TIME THE UPPER FLOW BECOMES MORE PARALLEL TO THE SURFACE FRONT WHICH
ALSO SLOWS DOWN ITS FORWARD PROGRESS. NEITHER MODEL CRANKING OUT
MUCH QPF ON SATURDAY DUE TO DISTANCE FROM SFC/UPPER LOWS AND
SCATTERED NATURE OF RW/TRW. BEYOND 48 HOURS THE COMBINATION OF COLD
AIR ALOFT AND JET DYNAMICS DEEPEN THE UPPER LOW AND CLOSE IT OFF BY
60 HOURS. THIS WILL ONLY SERVE TO DEEPEN THE ASSOCIATED SURFACE LOW
AND FURTHER SLOW DOWN THE MOVEMENT OF THE FRONT. GIVEN ALL OF
THIS...THE FRONT SHOULD MAKE IT TO OUR WESTERN BORDER AROUND MIDDAY
SUNDAY AND CLEAR THE EASTERN SECTIONS AROUND MIDDAY MONDAY. AS A
RESULT...WILL KEEP LIKELY POPS ON SUNDAY AND WILL END PRECIP ON
MONDAY FROM WEST TO EAST. IN THE WAKE OF THIS SYSTEM HIGH PRESSURE
AT THE SURFACE AND ALOFT WILL DOMINATE THROUGH THE END OF NEXT
WEEK.

HIGHS HAVE BEEN RUNNING A FEW DEGREES ABOVE THE WARMEST GUIDANCE...
SO WILL GENERALLY STAY AT OR A BIT ABOVE WARMEST GUIDANCE FOR HIGHS
AND LOWS THROUGHOUT THE FORECAST.

.PAH...NONE.

JAP

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-100-
107>112-114-071900-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE PADUCAH KY
1106 AM CDT FRI SEP 7 2001

THIS THUNDERSTORM OUTLOOK IS FOR SOUTHEAST MISSOURI...SOUTHERN
ILLINOIS...SOUTHWEST INDIANA...AND WESTERN KENTUCKY. IT IS VALID
UNTIL 600 AM SATURDAY.

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON IN A VERY WARM AND UNSTABLE AIRMASS WITH THE PROBABILITY
INCREASING FROM EAST TO WEST ACROSS OUR COUNTY WARNING AREA. WIND
SHEAR...LIFT AND INSTABILITY ARE WEAK...SO NO ORGANIZED SEVERE
ACTIVITY IS EXPECTED. AS USUAL...THE POTENTIAL FOR A STORM OR TWO TO
BRIEFLY PULSE TO SEVERE LIMITS IS ALWAYS A POSSIBILITY. THE MAIN
THREAT THIS AFTERNOON AND EVENING WITH THE STRONGER STORMS WILL BE
SMALL HAIL AND WIND GUSTS UP TO 40 MPH. ATMOSPHERIC MOISTURE REMAINS
VERY DEEP...SO LOCALLY HEAVY RAINFALL CONTINUES TO BE A POSSIBILITY.
NO MAJOR FLOODING PROBLEMS ARE EXPECTED HOWEVER...AS STORMS WILL NOT
BE SLOW MOVING OR STATIONARY.

STORM MOVEMENT WILL BE TOWARD THE NORTH NORTHEAST AT 25 MPH.

SPOTTER ACTIVATION IS NOT ANTICIPATED THIS AFTERNOON OR TONIGHT.

JAP

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PADUCAH KY
114 PM CDT FRI SEP 07 2001

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

1215 PM    5S VIENNA                 IL   WIND DAMAGE
09/07/01   JOHNSON                        A FEW TREES AND
                                          POWERLINES DOWN. REPORTED
                                          BY JOHNSON COUNTY
                                          SHERIFFS OFFICE