Severe Thunderstorm Warning 249, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
310 PM CDT SUN AUG 3 2003

UPPER WAVE LIFTING OUT OF ERN NEVADA INTO IDAHO WILL ACT TO FLATTEN
OUT UPPER RIDGE AND ESTABLISH A MORE WESTERLY FLOW ALOFT TONIGHT
THROUGH MONDAY. UPPER WAVE LIFTING OUT OF WRN CO WILL BE THE FIRST
TO BRING TSRA CHANCES TO OUR WEST BY LATE THIS EVENING. IN
ADDITION...POSSIBILITY FOR SOME ELEVATED CONVECTION TO DEVELOP
ACROSS NERN HALF OF CWFA AFTER MIDNIGHT IN AREA OF UPPER
DIVERGENCE...H85 WAA AND 2D FRONTOGENESIS.

A LOOK AT SFC DWPTS IN THE REGION...MID 60S COMMON ACROSS SRN
NEBRASKA AND UPPER 60S TO NEAR 70 WRN KS. ALSO THE PWS ARE AOA
NORMAL ACROSS THE CENTRAL PLAINS INTO THE INTERMOUNTAIN WEST RANGING
FROM 125 TO 175 PERCENT ABOVE NORMAL. THIS EVIDENT ON WV IMAGERY AS
WELL WITH MONSOONAL MOISTURE SOURCE DRAWN UP FROM BAJA. GOOD
MOISTURE CONVERGENCE ALONG AND EAST OF H85 TROUGH ADVANCING EAST
LATER TONIGHT AND MONDAY. POTENTIAL FOR LOCALLY HEAVY RAIN PSBL WITH
RATHER SLOW STORM MOTION. WILL EXAMINE THE SFC PRESSURE FALLS
FORECAST BY THE GFS AND ETA AS WELL TO FAVOR AREAS OF HIGHER POPS.

VORT MAX FCST BY 00Z ETA RUN ACROSS WRN CO INTO CENTRAL WY MATCHES
WELL WITH ITS POSN ON WV IMAGERY AS CONVECTION BEGINNING TO DEVELOP
AT 1830Z. SOME OF THE ACTIVITY SHOULD BEGIN TO MOVE INTO FAR WRN
CWFA AFTER 02Z.

ON MONDAY...UPPER RIDGE FLATTENS AND BECOMES SLIGHTLY SOUTHEAST IN
FLOW BY 00Z TUE. WHILE STRONGEST VORT MAX MOVES ACROSS SOUTH
DAKOTA...TRAILING WEAKER WAVE WILL EXTEND BACK THROUGH NEBR PNHDL
AND CO. AVBL MOISTURE AND INSTABILITY WILL BE MORE THAN ADEQUATE TO
FUEL STORMS. BEST AREAL COVERAGE OF STORMS WILL OCCUR WITH LATE
AFTERNOON PEAK HEATING. DECENT INSTABILITY WITH BEST SHEAR ACROSS
THE NORTH.

EXTENDED DISCUSSION...UPPER RIDGE ESTABLISHED ACROSS THE CENTRAL AND
NORTHERN PLAINS. TEMPS RESPOND BY BECOMING INCREASINGLY WARM EACH
DAY AND DRY THROUGH THE PERIOD.

.LBF...NONE.

ROBERG

NEZ004>010-022>029-035>038-056>059-069>071-094-041030-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
435 PM CDT SUN AUG 3 2003

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

.DAY ONE...TODAY

AN AREA OF LOW PRESSURE STRETCHES ACROSS THE FRONT RANGE OF THE
ROCKIES AND WILL BE THE FOCUS OF THUNDERSTORMS WELL WEST OF
THE AREA.  THESE THUNDERSTORMS WILL TRAVEL NORTHEAST BEFORE
DROPPING BACK TOWARD WESTERN NEBRASKA LATER TONIGHT.

TO THE EAST...INCREASING WINDS ABOVE THE SURFACE OVERNIGHT WILL
BRING A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS NORTH
CENTRAL NEBRASKA OVERNIGHT.  THESE THUNDERSTORMS WILL DIMINISH
DURING THE EARLY MORNING HOURS ON MONDAY.

ANY STORMS THAT DO FORM TONIGHT WILL HAVE THE POTENTIAL TO PRODUCE
SEVERE WEATHER TONIGHT AND OVERNIGHT...WITH HAIL BEING THE PRIMARY
THREAT AND MAINLY NORTH OF HIGHWAY 2.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

A BETTER CHANCE FOR SEVERE WEATHER EXISTS ON MONDAY WITH A SLIGHT
RISK FOR SEVERE THUNDERSTORM DEVELOPMENT.  THE AREA OF LOW PRESSURE
NEAR THE FRONT RANGE IS EXPECTED TO MOVE EAST ACROSS THE PLAINS.
LOW LEVEL WIND FIELDS WILL FAVOR THE POSSIBILITY OF DAMAGING
THUNDERSTORM WIND GUSTS AND EVEN ISOLATED TORNADOES AND LARGE HAIL.

MONDAY/S SEVERE WEATHER POTENTIAL COULD BEGIN EARLY IN THE DAY
ACROSS THE WEST AND THEN REMAIN A THREAT AREAWIDE THROUGH LATE
MONDAY AFTERNOON.  RAINFALL FROM STORMS EARLY MONDAY COULD BE HEAVY
BUT LATER IN THE DAY...INCREASING INSTABILITY AND SOME DRIER AIR
COULD BRING MORE INTENSE THUNDERSTORM WINDS.

MAINLY DRY AND WARMER CONDITIONS ARE EXPECTED BEYOND TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS POSSIBLE BUT NOT LIKELY THIS EVENING AND
OVERNIGHT...HOWEVER SPOTTERS MAY BE NEEDED ON MONDAY.

HIRSCH