Severe Thunderstorm Warning 220, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
305 PM CDT SAT JUL 19 2003

...FORECAST CHALLENGE HIGHLIGHTED BY PRECIP CHANCES FIRST 36
HOURS...THEN TEMPS...

H5 PATTERN TODAY HIGHLIGHTED WITH RIDGING ACROSS THE CENTER AND WRN
CONUS AND TROFING IN THE EAST. STRONG UPPR LOW OVER NRN SASKATCHEWAN
WILL CONTINUE SSEWD TREK OVER THE NEXT 48 HRS. HT FALLS AS WELL AS
WV IMAGERY ARE SUPPORTING THIS NOTION. CLOSER TO HOME...ACTIVE FLOW
AROUND NRN PERIPHERY OF UPPR HIGH CONTINUES WITH DECENT SHORTWAVES
ALREADY SHOWING UP ON WV IMAGERY. AT THE SFC...WEAK ERLY FLOW TODAY
AND ABUNDANT MOISTURE HAS KEPT TEMPS IN CHECK TODAY...HOWEVER WITH
DEW POINTS WELL INTO THE 60S W TO WYOMING...LITTLE RELIEF HAS BEEN
SEEN. MAIN DILEMMA TONIGHT WILL BE IF CONVECTION CAN FIRE WITH WAVE
ARRIVAL AND WHETHER OR NOT IT CAN SUSTAIN ITSELF AS IT MOVES EAST.

.NEAR TERM...CONVECTIVE TEMPS ARE A TAD TOO HIGH TODAY ACROSS
CENTRAL AND ERN PORTION OF THE FA. SO CONVECTION WILL HAVE TO
ORIGINATE ACROSS THE FAR WEST AND PANHANDLE. WEAK MID LVL SHEAR
TONIGHT SHOULD KEEP SEVERE THREAT IN CHECK. WITH THE LACK OF A
DECENT LL JET OVERNIGHT...CONVECTION...ACROSS THE FA SHOULD WEAKEN
CONSIDERABLY AFTER SUNSET. MORE WIDESPREAD CONVECTION LOOKS LIKE A
BETTER BET ON SUNDAY AS A DECENT SURFACE FRONT TRAVERSES FA. CAPE
ACROSS THE FA REMAINS FAIRLY HIGH TOMORROW WITH VALS IN EXCESS OF
1500J/KG. WITH AFTERNOON HEATING AND FAIRLY WEAK CIN...TSRAS SHOULD
DEVELOP ALONG THIS FEATURE FAIRLY QUICKLY BY AFTN. PRECIP WILL COME
TO AN END BY LATE EVENING AS FRONT PUSHES S OF THE AREA. THIS WILL
ALLOW SOMEWHAT DRIER AIR TO FILTER INTO THE FA FOR MONDAY AND
TUESDAY. DRY FCST CONTINUED...HOWEVER WE COULD POP AN ISOLATED TSRA
IN THE AFTERNOON (PARTICULARLY IN THE WEST) WITH THE NWRLY FLOW
ALOFT. AT THIS JUNCTURE...WILL LEAVE FCST AS IS AS TIMING OF WAVES
TRICKY.

.EXTENDED...WEDNESDAY THROUGH SATURDAY...THE ECMWF AND GFS SOLNS IN
DECENT AGREEMENT OUT TO THURSDAY WITH THE UPPER LVL TROF CONTINUING
TO DE-AMPLIFY ACROSS THE ERN CONUS EARLY BY MIDWEEK. TEMPS SHOULD
BEGIN TO RISE AND APPROACH CLIMO BY WED/THURS WITH READING EXCEEDING
THIS LATE IN THE WEEK.  THE CANADIAN SOLN SOMEWHAT WARMER TOWARD
MIDWEEK WITH A STRONGER UPPR LVL HIGH ANCHORED OVER THE SW. WILL
COMPROMISE AND GO WITH TEMPS JUST A TAD HIGHER THAN GUIDANCE. AS FOR
PRECIP...AFTER DRY CONDS ON WEDNESDAY AND THE FIRST HALF OF
THURSDAY...STRONG UPPR LOW OVER CENTRAL CANADA (5550 GPM @ H5) WILL
DRIVE A DECENT FRONTAL BOUNDARY THROUGH THE FA EARLY ON FRIDAY. POPS
WILL BE RETAINED...HOWEVER WITH HIGH PRESSURE DRIFTING INTO THE FA
LATE ON FRIDAY...DRY FCST ON TRACK FRIDAY NIGHT INTO EARLY ON
SATURDAY FOR MOST OF THE FA EXCEPT THE ERN ZONES. WILL SEE SOME
RETURN SRLY FLOW ON SATURDAY AS SFC HIGH DRIFTS EWD AND THETA E
RIDGE BUILDS INTO THE HIGH PLAINS. WITH THIS IN MIND...WILL INITIATE
LOW POPS IN THE WEST
SAT AFTN/EVE.

.LBF...NONE.

CLB

NEZ004>010-022>029-035>038-056>059-069>071-094-201030-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
335 PM CDT SAT JUL 19 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND NORTH CENTRAL
NEBRASKA.

.DAY ONE...TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TONIGHT OVER WESTERN
NEBRASKA...WEST OF A LINE FROM VALENTINE TO HYANNIS TO OGALLALA. AN
UPPER LEVEL DISTURBANCE WILL EXIT EASTERN WYOMING AND MOVE INTO THE
BLACK HILLS OF SOUTH DAKOTA...THE NEBRASKA PANHANDLE AND NORTHEAST
COLORADO TONIGHT TRIGGERING THUNDERSTORM DEVELOPMENT. SCATTERED
THUNDERSTORMS ARE EXPECTED TO MOVE INTO THE OUTLOOK AREA TONIGHT.
DUE TO WARM TEMPERATURES AND WEAK WINDS IN THE MID LEVELS OF THE
ATMOSPHERE...LARGE HAIL WILL NOT BE A CONCERN. WITH ABOVE NORMAL
MOISTURE CONTENT AND SLOW STORM MOVEMENT...LOCALLY HEAVY RAINFALL IS
POSSIBLE WITH STORMS THAT DO MOVE INTO THE AREA. THE MAIN THREAT
WILL BE ISOLATED DAMAGING WIND GUSTS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY
THUNDERSTORMS WILL BE POSSIBLE SUNDAY AND MONDAY AS A SERIES OF WEAK
DISTURBANCES ALOFT MOVE ACROSS THE REGION. WITH THE ATMOSPHERE LESS
UNSTABLE ANY THUNDERSTORMS WHICH DEVELOP ARE UNLIKELY TO BECOME
SEVERE. DRIER AIR WILL MOVE INTO THE OUTLOOK AREA ON TUESDAY AND
WEDNESDAY THUS DIMINISHING THE CHANCES FOR THUNDERSTORMS. BY LATE
THURSDAY AND FRIDAY...MOISTURE WILL RETURN TO THE OUTLOOK AREA AS A
SURFACE FRONT AND DISTURBANCE ALOFT PROVIDE THE FOCUS FOR THE CHANCE
OF THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NECESSARY TONIGHT.

POWER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORTH PLATTE NE
0531 PM CDT SAT JUL 19 2003

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

0525 PM    11 NE THEDFORD            NE   0.88 IN HAIL
07/19/03   CHERRY                         PEA TO NICKEL SIZE HAIL
                                          COVERING GROUND

MB

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
0531 PM CDT SAT JUL 19 2003

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

0525 PM    11 NE THEDFORD            NE   0.88 IN HAIL
07/19/03   THOMAS                         PEA TO NICKEL SIZE HAIL
                                          COVERING GROUND

MB