Tornado and Hail in Nebraska, August 15, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
224 PM CDT SUN AUG 15 2004

...FORECAST CHALLENGE IS POPS...

.DISCUSSION...
AT 18Z SURFACE FRONT WAS SOUTH OF THE BLACK HILLS WITH MODELS
CONTINUING TO SLOW FEATURE DOWN WHILE MOVING SOUTHEAST. LAPS DATA
SHOWS CAPE VALUES TO 2400 J/KG OVER THE CENTRAL NEB PANHANDLE WITH
AXIS OF GREATEST INSTABILITY NORTHEAST ACROSS THE PANHANDLE. VISIBLE
SATELLITE SHOW CU FORMING IN ADVANCE OF THE FRONT AS SURFACE HEATING
HAS HELPED FURTHER DESTABILIZE THE ATMOSPHERE...AND WV IMAGERY SHOWS
WAVE DROPPING SE ACROSS WESTERN SD MORE IN LINE WITH ETA SOLUTION
WITH STORMS IN THE NEAR TERM. RADAR MOSAIC HAS ISOLATED CELLS FROM
SOUTH CENTRAL SOUTH DAKOTA INTO THE NORTHWEST PANHANDLE ATTM.

ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP ACROSS THE
WEST THIS EVENING THEN WITH THE LOSS OF HEATING STORMS WEAKENING AND
DISSIPATING ACROSS THE WEST WHILE SCATTERED SHOWERS/THUNDERSTORMS
MOVE INTO THE NORTH CENTRAL OVERNIGHT. FRONT BECOMES ILL-DEFINED AS
IT MOVES SOUTHEAST OVERNIGHT INTO MONDAY WITH INCREASING ANTICYCLONIC
FLOW ALOFT ACROSS THE WEST. WITH NO SIGNIFICANT WAVE TO MOVING
SOUTHEAST ON MONDAY REMOVED ALL PRECIP EXCEPT EXTREME EAST IN NORTH
CENTRAL DURING THE MORNING HOURS.

MONDAY NIGHT UPSLOPE FLOW WILL BE REDIRECTED SOUTH TO ALONG
THE COLORADO HIGH PLAINS AS SURFACE HIGH RIDGES SOUTHEAST INTO
WESTERN NEBRASKA. UPPER RIDGE AXIS WILL WEAKEN OVERNIGHT AS
DISTURBANCES MOVE INTO THE RIDGE AXIS WITH CHANCE FOR THUNDERSTORMS
TUESDAY. TUESDAY MODELS IN GENERAL AGREEMENT BUT DIFFER IN
PLACEMENT OF CONVECTION AS DISTURBANCE MOVES SOUTHEAST WITH MODEL
BLEND USED.

BEYOND TUESDAY MODELS HAVING A TIME IN HOW TO HANDLE WEST
COAST UPPER RIDGE AND ENERGY TO MOVE SOUTHEAST. TRENDED WITH
PREVIOUS MODEL CONSISTENCY WHERE GFS KEEPS MAIN FORCING TO
THE SOUTHWEST. UNTIL MODEL CONSISTENCY INCREASES FOCUSING LIFTING
ENERGY TO THE NORTHEAST THURSDAY WILL GRIDS AS IS. TEMPERATURES
TO REMAIN AT OR NEAR NORMAL AS COLDEST AIR SKIRTS SOUTHEAST ACROSS
THE NORTHERN MIDWEST AND GREAT LAKES REGION.
&&

.LBF WATCHES/WARNINGS/ADVISORIES...NONE.

&&

TLK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
335 PM CDT SUN AUG 15 2004

NEZ004>010-022>029-035>038-056>059-069>071-094-161030-
ARTHUR NE-BLAINE NE-BOYD NE-BROWN NE-CHASE NE-CUSTER NE-DEUEL NE-
EASTERN CHERRY NE-FRONTIER NE-GARDEN NE-GARFIELD NE-GRANT NE-
HAYES NE-HOLT NE-HOOKER NE-KEITH NE-KEYA PAHA NE-LINCOLN NE-LOGAN NE-
LOUP NE-MCPHERSON NE-PERKINS NE-ROCK NE-SHERIDAN NE-THOMAS NE-
WESTERN CHERRY NE-WHEELER NE-
INCLUDING THE CITIES OF...AINSWORTH...ARNOLD...ARTHUR...BASSETT...
BIG SPRINGS...BREWSTER...BROKEN BOW...BURWELL...CHAPPELL...CURTIS...
GORDON...GRANT...HAY SPRINGS...HAYES CENTER...IMPERIAL...MULLEN...
NORTH PLATTE...ONEILL...OGALLALA...OSHKOSH...RUSHVILLE...SPENCER...
SPRINGVIEW...STAPLETON...TAYLOR...THEDFORD...TRYON AND VALENTINE
335 PM CDT SUN AUG 15 2004

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

.DAY ONE...TONIGHT

THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE ACROSS MOST OF WESTERN AND
NORTH CENTRAL NEBRASKA THIS EVENING AND TONIGHT...MAINLY NORTH OF
INTERSTATE 80S. A FEW OF THESE STORMS MAY REACH SEVERE LIMITS...WITH
LARGE HAIL AND DAMAGING WINDS...ALONG AND NORTH OF LINE FROM OSHKOSH
IN GARDEN COUNTY...TO ONEILL IN HOLT COUNTY. GUSTY SOUTHERLY WINDS
WERE TRANSPORTING MOISTURE NORTHWARD...AND INTERSECTING A SURFACE
BOUNDARY ACROSS NORTHWEST AND NORTH CENTRAL NEBRASKA. STRONG HEATING
AND UPPER LEVEL DISTURBANCE WILL HELP SPREAD THESE STRONG
THUNDERSTORMS SOUTHEAST INTO PORTIONS OF WEST CENTRAL AND NORTH
CENTRAL NEBRASKA THROUGH THE EVENING HOURS. A FEW THUNDERSTORMS MAY
LINGER INTO THE EARLY MORNING HOURS...EAST OF HIGHWAY 83...BUT ARE
NOT EXPECTED TO REACH SEVERE LIMITS AFTER SUNSET.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THE FRONTAL BOUNDARY...MENTIONED ABOVE WILL STALL ACROSS SOUTHERN
PORTIONS OF THE OUTLOOK AREA ON MONDAY AND TUESDAY. THUNDERSTORMS ARE
POSSIBLE ON MONDAY AFTERNOON AND EVENING ACROSS WESTERN PORTIONS OF
THE OUTLOOK AREA. SOME OF THESE MAY APPROACH SEVERE LIMITS WITH LARGE
HAIL THE MAIN THREAT. A BETTER CHANCE FOR SEVERE WEATHER EXISTS ON
TUESDAY ACROSS SOUTHERN PORTIONS OF THE OUTLOOK AREA. THIS AREA IS
MAINLY SOUTH OF A LINE FROM OGALLALA TO BROKEN BOW. LARGE HAIL IS THE
MAIN SEVERE WEATHER THREAT.

THUNDERSTORMS ARE POSSIBLE WEDNESDAY AFTERNOON AND EVENING. AT THIS
TIME...NO SEVERE WEATHER IS EXPECTED.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING ACROSS
NORTHERN AND WESTERN PORTIONS OF THE OUTLOOK AREA.

CLB/13