Severe Thunderstorm Warning 243, NWS Hastings, NE

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
334 AM CDT MON AUG 18 2003

LATEST SURFACE ANALYSIS SHOWS TROUGH/OUTFLOW PUSHING SLOWLY ACROSS
WESTERN HALF OF NEBRASKA AS ASSOCIATED SURFACE LOW SITS ACROSS THE
DAKOTAS.  WATER VAPOR IMAGERY INDICATES HEALTHY SHORT WAVE DIGGING
INTO CENTRAL ROCKIES WITH WEAKER LEAD WAVES BEING KICKED OUT AHEAD
OF MAIN SYSTEM INTO THE PLAINS.  THIS ALONG WITH DEVELOPMENT OF
MARGINAL LLJ INTO WESTERN SECTIONS OF FORECAST AREA HAS RESULTED IN
SOME ISOLATED CONVECTION FORMING AHEAD OF SURFACE TROUGH OVER PARTS
OF CENTRAL NEBRASKA.  MODELS ARE PRETTY CLOSE ON INITIALIZATION BUT
NEITHER ETA OR GFS APPEAR TO BE CATCHING EXACT LOCATION OF
PRECIPITATION.  ETA LOOKS OVERDONE WHILE GFS IS A TAD UNDERDONE SO
WILL HAVE TO WING FOR FIRST PERIOD OF FORECAST.

FIRST CHALLENGE OF THE DAY IS EXTENT AND DURATION OF EXISTING
CONVECTION OVER WESTERN HALF OF FA.  LOOKS AS THOUGH CONVECTION
SHOULD FADE ONCE LLJ WEAKENS BY MID MORNING AND MID LEVEL WAVE SLIPS
NORTH OF CWA.  WILL KEEP ISOLATED PRECIP MENTION ACROSS THIS AREA
FOR START OF PERIOD.  AFTER THIS...UPPER WAVE CONTINUES TO DIG INTO
CENTRAL ROCKIES WITH WELL DEVELOPED CYCLONE ACROSS NORTHERN PLAINS
HELPING TO KEEP SURFACE TROUGH NEAR AREA.  EXPECT THIS WILL KEEP
BEST SHOT OF PRECIP OVER WESTERN HALF OF NEBRASKA COUNTIES DURING
THE AFTERNOON/EARLY EVENING.  TEMPS LOOK WARM ONCE AGAIN TODAY WITH
MET GUIDANCE VALUES LOOKING REASONABLE IN THE MID 90S TO AROUND 100.

UPPER SYSTEM THEN BEGINS TO KICK OUT OF THE ROCKIES TONIGHT WITH
REDEVELOPMENT OF MARGINAL LLJ AFTER DARK.  THIS MAY PROVIDE THE FUEL
TO ALLOW ADDITIONAL CONVECTION TO SPREAD OVER REMAINDER OF
AREA...ALTHOUGH COVERAGE IS STILL SOMEWHAT QUESTIONABLE SINCE
SURFACE TROUGH IS SHOWN TO REMAIN MAINLY OVER/NEAR NORTHWESTERN
THIRD OF AREA.  WILL KEEP MENTION OF ISOLATED PRECIP BUT THIS MAY
NEED TO BE BUMPED UP SLIGHTLY BY DAY CREW.  WAVE THEN MOVES INTO THE
HIGH PLAINS ON TUESDAY INTO TUESDAY NIGHT.  THIS LOOKS TO SET OFF
ANOTHER ROUND OF CONVECTION OVER WESTERN THIRD OF NEBRASKA COUNTIES
BY AFTERNOON.  THIS SHOULD SPREAD OVER REMAINDER OF AREA BY EVENING
AS STRONGER DYNAMICAL FORCING MOVES INTO AREA.

PATTERN BECOMES QUIET AGAIN ON WEDNESDAY AS UPPER WAVE SLIDES EAST
OF AREA. SUBSIDENCE BEHIND WAVE SHOULD CLEAR OUT MOST PRECIP AND
CLOUD COVER BY EARLY AFTERNOON.  WITH FRONT REMAINING NORTH OF AREA
AND DOWNSLOPE WINDS DEVELOPING ACROSS AREA...GUIDANCE TEMPS LOOK A
TAD TOO COOL.  WILL AIM TEMPS INTO THE MID 90S NEAR LEXINGTON/ORD
AREA TO UPPER 90S ACROSS NORTH CENTRAL KANSAS.

FORECAST BEYOND WEDNESDAY STILL LOOKS GENERALLY DRY AND WARM SO WILL
MAKE NO CHANGES TO THIS TIME PERIOD.

.GID...NONE.

AWJ

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-191200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HASTINGS NE
1101 AM CDT MON AUG 18 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL NEBRASKA AND
PARTS OF NORTH CENTRAL KANSAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

A FEW ISOLATED SHOWERS AND THUNDERSTORMS WILL LINGER ACROSS SOUTH
CENTRAL NEBRASKA EARLY THIS AFTERNOON. NONE OF THESE THUNDERSTORMS
WILL REACH SEVERE LIMITS.

AFTER 4 PM...SOME REDEVELOPMENT OF THUNDERSTORMS IS POSSIBLE AS AN
UPPER LEVEL DISTURBANCE SLIPS EAST FROM THE ROCKIES. A WEAK SURFACE
TROUGH WILL BE THE FOCUS FOR THUNDERSTORMS...PRIMARILY ALONG AND
WEST OF A FULLERTON NEBRASKA TO PHILLIPSBURG LINE. WEAK WIND FIELDS
WILL LIMIT STORM INTENSITY...BUT AN ISOLATED STRONG TO SEVERE
THUNDERSTORM IS POSSIBLE INTO THE EARLY EVENING HOURS. HAIL AND
LOCALIZED HEAVY RAINFALL WILL BE THE PRIMARILY THREATS...ALTHOUGH
WIDESPREAD SEVERE WEATHER IS NOT LIKELY. THE THUNDERSTORMS WILL
DIMINISH AROUND SUNSET...BUT MAY FORM AGAIN TOWARD SUNRISE TUESDAY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE TUESDAY
INTO TUESDAY NIGHT AS THE UPPER LEVEL DISTURBANCE MOVES ACROSS THE
AREA.  WINDS ALOFT WILL REMAIN WEAK BUT THE ATMOSPHERE MAY BECOME
MORE STRONGLY UNSTABLE THAN ON MONDAY.  THIS MAY ALLOW AN ISOLATED
STORM OR TWO TO BECOME STRONG OR SEVERE OVER SOUTH CENTRAL
NEBRASKA AND NORTH CENTRAL KANSAS.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER ACTIVATION WILL NOT BE NEEDED THIS AFTERNOON OR
TONIGHT.

MORITZ