Severe Thunderstorm Warning 20, NWS Hastings, NE

SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
214 AM CDT TUE APR 29 2003

...MAIN CONCERN IS SEVERE WEATHER POTENTIAL SETTING UP FOR TONIGHT...

SATL PIX AND LATEST UAA SHOWING AN UPPER LEVEL LOW SPINNING OVER THE
COAST NEAR THE PACIFIC NW. A FEW IMPULSES IDENTIFIED BEING EJECTED
FROM THE MAIN CIRCULATION...MOVING ACROSS THE GREAT BASIN AND
HEADING TOWARD THE ROCKIES. IMPRESSIVE JET CORE ANALYZED AT THE
BOTTOM OF THE CIRCULATION TOO. 850MB ANALYSIS SHOWING AXIS OF
MOISTURE STRETCHING FROM THE GULF COAST OF TEXAS INTO NRN KANSAS.
LATEST 850 MB PROFILERS INDICATING WINDS INCREASING UP TO AROUND 40KT
ACROSS TEXAS AND OKLA...HELPING FEED THE MOISTURE INTO THE PLAINS.

AS MENTIONED...MAIN CONCERN IS FOR POTENTIAL SEVERE OUTBREAK THIS
EVENING AND OVERNIGHT. THE LATEST ETA IS INDICATING STOUT INSTABILITY
ACCOMPANIED BY IMPRESSIVE ATMOSPHERIC SHEAR. IT APPEARS THAT SFC LOW
PRESSURE SHOULD BE DEEPENING NEAR WRN KS BY 00Z TONIGHT AS THE MAIN
UPPER LEVEL CIRCULATION HEADS FOR THE GREAT BASIN. ETA INSTABILITY
PARAMETERS BASICALLY BULLSEYE KS WITH 4000J/KG SBCAPE...LIS
OF -9...AND TTS ABOVE 60 BY EARLY EVENING...ACCOMPANIED BY AN
INCREASING LOW LEVEL JET. AS THE SFC LOW DEVELOPS SW OF THE AREA...
SHEAR INDICES CATAPULT ACROSS THE CWA SUGGESTING SUPERCELLS AS THE
MAIN THREAT. PLENTY OF MOISTURE PROGGED FOR THE AREA AS PRECIPITABLE
WATER VALUES ARE ABOUT 1.50. WITH THIS HIGH CONCENTRATION OF
LOW LEVEL MOISTURE UNDERNEATH STEEP MID LEVEL LAPSE RATES...LARGE
HAIL A DEFINITE POSSIBILITY WITH SOME STORMS. BOTTOM LINE IS THAT
TORNADIC SUPERCELLS APPEAR QUITE PROBABLE DURING THE EVENING HOURS
OVER THE CWA.

AS FOR THE REST OF THE FORECAST...THUNDER CHANCES SEEM REASONABLE
THRU AT LEAST THURSDAY MORNING AS THE UPPER LEVEL LOW CROSSES THE
ROCKIES AND TREKS THRU THE PLAINS. SEVERE WX STILL POSSIBLE MAINLY
IN EASTERN SECTIONS OF OUR NEB CWA WEDNESDAY NIGHT AS SUFFICIENT
LARGE SCALE FORCING ACCOMPANIES INCREASING INSTABILITY PARAMETERS.

ONLY MINOR ADJUSTMENTS MADE TO THE EXTENDED PORTION OF FCST.

.GID...NONE.

DEE

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-301200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HASTINGS NE
500 AM CDT TUE APR 29 2003

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A RISK OF SEVERE THUNDERSTORMS LATER THIS AFTERNOON AND
TONIGHT. THE MAIN SEVERE WEATHER HAZARDS ARE LARGE HAIL...AND
POSSIBLY A FEW TORNADOES. THUNDERSTORMS ARE EXPECTED TO DEVELOP LATER
THIS AFTERNOON ALONG A FRONTAL BOUNDARY STRETCHING ACROSS SOUTHERN
NEBRASKA AND NORTHERN KANSAS. AS THE ATMOSPHERE BECOME MORE MOIST AND
UNSTABLE....THUNDERSTORMS WILL BECOME MORE WIDESPREAD AND ORGANIZED.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

ON WEDNESDAY...DEEP SURFACE LOW PRESSURE IS EXPECTED TO BE OVER
WESTERN KANSAS BY LATE AFTERNOON...WITH A FRONTAL BOUNDARY
EXTENDING EASTWARD INTO SOUTHEAST NEBRASKA. DAYTIME HEATING AND
INCREASING LARGE SCALE LIFT AHEAD OF AN APPROACHING UPPER LEVEL
TROUGH WILL LIKELY LEAD TO SCATTERED THUNDERSTORM DEVELOPING NEAR
THE FRONTAL BOUNDARY. THIS ENVIRONMENT SHOULD BE VERY FAVORABLE
FOR STRONG THUNDERSTORMS CAPABLE OF PRODUCING VERY LARGE HAIL AND
DAMAGING WINDS...MAINLY FOR AREAS EAST OF HIGHWAY 281 AND NORTH OF
INTERSTATE 80.

THUNDERSTORM CHANCES WILL EXIST UNTIL THURSDAY MORNING...THEN AGAIN
THIS WEEKEND.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER ACTIVATION WILL BE REQUIRED LATER THIS AFTERNOON AND
TONIGHT.

DEE