Hail in Nebraska, May 13, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
210 AM CDT TUE MAY 12 2003

PRECIP CHANCES TODAY AND TEMPS NEXT SEVERAL DAYS MAIN CHALLENGE.

WATER VAPOR IMAGERY FROM THIS EARLY MORNING SHOWS STRONG UPPER WAVE
MOVING ACROSS THE NORTHERN ROCKIES.  AT THE SURFACE LEE
TROUGH/DRYLINE EXTENDS SOUTH ACROSS THE NORTHERN AND CENTRAL HIGH
PLAINS WITH DEEPER BOUNDARY LAYER MOISTURE SLOWLY ADVECTING NORTH
OUT OF THE SOUTHERN PLAINS.  MODELS ARE FAIRLY CLOSE WITH SYSTEM
EVOLUTION THROUGH NEXT 60 HOURS BUT ETA IS SLIGHTLY QUICKER WITH
PROGRESSION OF WAVE THROUGH NORTHERN PLAINS TODAY.  WILL AIM
SOMEWHERE BETWEEN THE ETA AND GFS FOR THIS FORECAST PACKAGE.

AFORE MENTIONED UPPER WAVE SLIDES OUT OF THE MOUNTAINS AND FORMS A
CUT OFF LOW OVER THE NORTHERN PLAINS TODAY.  THIS WILL PUSH DRYLINE
QUICKLY THROUGH AREA FROM WEST TO EAST THIS AFTERNOON WITH TRAILING
COLD FRONT SURGING INTO NORTHWEST CORNER AS WELL.  LARGE SCALE
ASCENT FROM WAVE WILL HELP TO KICK OFF CONVECTION ALONG DRYLINE BUT
MAIN QUESTION BECOMES HOW FAR WILL DRYLINE PUSH EAST BEFORE
CONVECTION FORMS.  APPEARS AS THOUGH ATMOSPHERE WILL REMAIN CAPPED
AHEAD OF DRYLINE UNTIL EARLY TO MID AFTERNOON.  BY THIS POINT
DRYLINE IS SHOWN TO HAVE CLEARED ALL BUT EASTERN MOST 6 TO 7
COUNTIES AND WILL GO WITH 30-40 POPS ACROSS THIS AREA.  DRYLINE AND
ASSOCIATED CONVECTION THEN QUICKLY CLEARS FORECAST AREA BY EARLY
EVENING.  SEVERE POTENTIAL LOOKS DECENT GIVEN 0-6KM SHEAR OF
40-50KTS AND CAPE VALUES AROUND 1500-2000 WITH MAIN THREAT BEING
LARGE HAIL. ONLY OTHER PRECIP POTENTIAL IS IMMEDIATELY BEHIND COLD
FRONT WHERE SOME RESIDUAL MOISTURE MAY BRING SOME ISOLATED SHOWERS
THROUGH EARLY EVENING AS WELL.  TEMPS LOOK WARM TODAY AS DRY
DOWNSLOPE WINDS BEHIND DRYLINE PUSH TEMPS INTO THE MID 70S TO LOWER
80S FOR HIGHS.

SUBSIDENCE THEN KICKS IN BEHIND FRONT TONIGHT AS UPPER WAVE MOVES
INTO THE UPPER MIDWEST REGION.  THIS WILL ALLOW REINFORCING SHOT OF
COOLER AIR TO SLIDE INTO FAR NORTHERN COUNTIES BY SUNRISE ON
WEDNESDAY.  THIS SHOULD BRING IN SOME STRATUS AS WELL BUT MOST OF
THE NIGHT LOOKS MOSTLY CLEAR OVER AREA.  PATTERN REMAINS QUIET INTO
THE LATTER HALF OF WEDNESDAY AS UPPER RIDGE BEGINS TO REBUILD OVER
REGION IN ADVANCE OF NEXT WAVE.  ONLY PROBLEM FOR THE DAY WILL BE
STRATUS MENTIONED ABOVE BUT FEEL IT WILL SCATTERED OUT BY EARLY
AFTERNOON.  CONDITIONS WILL BE A TAD COOLER BEHIND FRONT WITH TEMPS
IN THE MID 60S TO LOWER 70S FOR HIGHS.

NEXT WAVE THEN PLOWS INTO REGION THURSDAY INTO EARLY FRIDAY.  LATEST
GFS AND ECMWF NOW DIG MOST OF ENERGY INTO SOUTHERN PLAINS INSTEAD OF
CENTRAL PLAINS AS PREVIOUS RUN OF GFS INDICATED.  WAVE IS ALSO
AROUND 12-18 HOURS QUICKER THAN PREVIOUS GFS RUN.  FOR THIS REASON
LOOKS AS THOUGH NEXT PRECIP CHANCE WILL COME AS EARLY AS LATE
MORNING/EARLY AFTERNOON ON THURSDAY BUT SHOULD BE OUT OF AREA BY
EARLY MORNING ON FRIDAY.  SATURDAY ALSO LOOKS MUCH DRIER THAN
PREVIOUS FORECAST AS IT BECOMES A TRANSITIONAL DAY BETWEEN OUTGOING
WAVE AND LARGER SYSTEM DIGGING INTO SOUTHWEST CONUS BY THE LATE
WEEKEND.  REMOVED PRECIP MENTION ON SATURDAY AND EARLY SUNDAY BUT
PRECIP STILL LOOKS POSSIBLE LATE SUNDAY INTO MONDAY AS LEE TROUGH
REESTABLISHES ITSELF AND SERIES OF WAVES KICK OFF MORE CONVECTION.

.LBF...NONE.

AWJ

NEZ004>010-022>029-035>038-056>059-069>071-094-132045-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1008 AM CDT TUE MAY 13 2003

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

.DAY ONE...TODAY AND TONIGHT

A LOW PRESSURE SYSTEM WILL MOVE EAST ALONG THE NEBRASKA SOUTH DAKOTA
BORDER THIS AFTERNOON AND TONIGHT. AS THE SYSTEM MOVES EAST THROUGH
THE AFTERNOON ABUNDANT SUNSHINE WILL CONTINUE TO DESTABLIZE AN
ALREADY UNSTABLE ATMOSPHERE. WITH LIMITED LOW LEVEL MOISTURE THE
MAIN CONCERN WILL BE FOR STRONG OUTFLOW WINDS AND LARGE HAIL WITH
THE THUNDERSTORMS THAT DO DEVELOP. THE AREA OF CONCERN FOR SEVERE
WEATHER DEVELOPMENT IS EAST OF A LINE FROM SPRINGVIEW...IN KEYA PAHA
COUNTY TO CURTIS IN FRONTIER COUNTY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A RETURN OF MOIST SOUTHERLY FLOW AHEAD OF AN AREA OF LOW PRESSURE
ACROSS THE HIGH PLAINS OF COLORADO AND WYOMING WILL SET THE STAGE
FOR THUNDERSTORM DEVELOPMENT AGAIN SUNDAY AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED BY MID AFTERNOON...MAINLY EAST OF
SPRINGVIEW TO CURTIS LINE.  STAY TUNED TO THE LATEST WEATHER
FORECASTS FOR UP TO DATE INFORMATION.

POWER