Severe Thunderstorm Warning 116, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
255 PM CDT MON JUL 2 2001

...FORECAST CHALLENGES WILL REMAIN THUNDERSTORM POTENTIAL AND
TEMPS INTO MID-WEEK...

18Z SFC ANALYSIS WAS SHOWING WARM FRONT OVER THE CENTRAL PART OF THE
STATE...PARTILLY DUE TO WETTER GROUNDS FROM RECENT RAINS. ALSO...
WEAK TROF FROM CENTRAL SD INTO SRN PANHANDLE. LAPS INDICATING DECENT
CONVERGENCE ALONG BOTH FEATURES...AND TCU DEVELOPING ON THE LATTER.
SHORT WAVE TROF MOVING ACROSS NRN WY AS PER WATER VAPOR IMAGERY...
WITH ANOTH MOVING SEWD ACROSS ERN MT. WEAK CONVECTION ACROSS C SD
DEVELOPING LTGCG ONCE AGAIN.

MODELS IN FAIR AGREEMENT WITH LARGE SCALE FEATURES...ALTHO HAVE
DIFFERING OPINIONS ON PLACEMENT OF CONVECTION THROUGH THE NEXT FEW
DAYS. ETA HAS TYPICALLY BEEN THE MODEL OF CHOICE AND WILL BE AGAIN
FOR THIS FORECAST...ALTHO THE AVN HAD MORNING CONVECTION IN MT A
LITTLE BETTER DEVELOPED.

N/S ORIENTED TROF WILL WORK ACROSS THE STATE...WITH SRN END GETTING
HUNG UP NEAR THE KS/NEB BORDER. BEST LOW LEVEL CIRCULATION WILL
LIKELY TAKE PLACE ACROSS THE PANHANDLE FOR THE REMAINDER OF THE
AFTERNOON WHERE THERMALL GRADIENT IS THE BEST...HOWEVER BEST 0-6 KM
SHEAR WILL EXIST FURTHER N...NEAR THE SD/NEBR BORDER. WOULD EXPECT
CONVECTION IS BOTH LOCATIONS WITHIN THE NEXT 6 HRS...WITH CORFIDI
VECTORS INDICATING AN ESEWD PROPAGATION TO CONVECTION IN NRN CWA.
IF STORMS DEVELOP FURTHER S AND FORM MCS INTO THE SWRN PORTION OF THE
STATE...IT SHOULD MOVE MORE SWD. HOWEVER...BEST POTENTIAL FOR MCS
EVELEMENT SHOULD BE ACROSS THE NRN HALF OF THE CWA. WOULD ALSO
EXPECT THAT SUPERCELL POTENTIAL WOULD BE BETTER IN THE NRN HALF OF
THE CWA. AS LOW LEVEL JET DEVELOPS OVERNIGHT...A LINEAR MCS WOULD
TEND TO PROAGATE SWWD SOME. ALL THIS POINTS TO INCLUDING POPS IN
ALL OF CWA...HIGHEST IN THE N AND W. HEAVY RAINS WILL ALSO BE
MENTIONED IN THE N...AS ETA FCST PRECIP H20 VALUES ARE BETTER THAN
AN INCH AND A HALF...AND 3-HR FFG VALUES ARE CLOSE TO THE SAME.

IF LINEAR MCS DOES DEVELOP AS EXPECTED...FRONTALL BOUNDARY WILL BE
PUSHED TO NEAR THE KS/NEBR BORDER INTO SERN WY. SHORT WAVE TROF AT
650 MB LEVEL INDICATED TO SWING OVER THE TOP OF THE UPPER RIDGE
POSITIONED OVER THE CENTRAL ROCKIES WOULD ALLOW FOR MID LEVEL
THERMAL GRADIENT TO TIGHTEN ONCE AGAIN...WITH A SETUP SIMILAR TO
SUNDAY NIGHT. ETA DOES DEVELOP LARGE CONMPLEX OVER THE PANHANDLE
WHICH LOOKS REASONABLE. A TAD BIT BETTER MID LEVEL COOLING SHOULD
KEEP LAPSE RATES HIGH...AND WITH LOW LEVEL FLOW UPSLOPE IN NATURE...
A MORE ORGANIZED SYSTEM LOOKS POSSIBLE. CORFIDI VECTORS FOR TUESDAY
NIGHT LOOK MORE SERLY...GIVING THE SW A BETTER CHANCE FOR PRECIP.

GUIDANCE VALUES  LOOK CLOSE BUT MAY MAKE ADJUSTMENTS TO AREAS THAT
HAVE RECEIVED THE MOST RAIN RECENTLY.

IN THE OUTER PERIODS...MED RANGE AND EXTENDED MODELS ALSO LOOK IN
DECENT AGREEMENT WITH THE LARGE SCALE FLOW. PATTERN REALY DOESN'T
CHANGE MUCH AS THE NRN STREAM STAYS BUSY. MRF MAY BE A BIT TOO
AGRESSIVE IN TIMING WITH NWRN STATES UPPER LOW DEVELOPMENT TO PASS
ALONG THE CANADIAN BORDER TWD THE WEEKEND...BUT AS WITH A TYPICAL
SUMMER TIME PATTERN...IT IS THE SMALL SCALE FEATURES THAT WILL HARD
TO PIN DOWN FOR TSRA DEVELOPMENT. WITH THE PLACEMENT OF THE UPPER
HIGH FROM THE SRN ROCKIES INTO THE SRN PLAINS...WEAK UPPER FEATURES
WILL WORK WITH LOW LEVEL CIRCULATIONS TO PRODUCE TSRA...WITH EACH
UPPER FEATURES PRODUCING A LEE TROF THAT WILL MOVE EWD BEFORE WASHING
OUT. WILL KEEP EXTENDED PRECIP WORDING THE SAME FOR THE MOST PART.

.LBF...NONE.

JWS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE, NE
634 PM CDT MON JUL 2 2001

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

0555 PM    30 N LEWELLEN             NE   1.50 INCH HAIL
07/02/01   GARDEN                         REPORTED BY SPOTTERS

0610 PM    19 S ASHBY                NE   1.75 INCH HAIL
07/02/01   GRANT                          REPORTED BY SPOTTERS

JZ