Tornado and Hail in Nebraska, July 21, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
321 AM CDT MON JUL 21 2003

...EXTENT OF CLOUDS/CONVECTION AND THE SUBSEQUENT AFFECT ON
TEMPERATURES TODAY AND TONIGHT ARE THE BIGGEST CHALLENGES...

SATELLITE IMAGERY SHOWS PLENTY OF CLOUD COVER ASSOCIATED WITH
SHORTWAVE MOVING INTO WESTERN SD.  THIS CLOUD COVER AND LIGHT
SHOWERS WILL CONTINUE TO SPREAD INTO THE NORTHWEST SECTION OF THE
CWA THIS MORNING.  THERE ARE ALREADY WEAK REFLECTIVITIES IN
SHERIDAN AND WESTERN CHERRY COUNTIES SO HAVE INCLUDED 20 POPS FOR
THIS MORNING IN MUCH OF THE NORTH.

THERE IS A SIGNIFICANT DIFFERENCE IN THE GFS AND ETA SOLUTIONS FOR
TODAY.  THE GFS IS MUCH SLOWER AND FURTHER WEST WITH THE SHORTWAVE
THAN THE ETA.  AT 06Z...THE ETA LOOKS MORE REASONABLE AS THE CURRENT
TRACK OF THE SHORTWAVE SHOULD TAKE IT INTO NORTH CENTRAL NEBRASKA
THIS MORNING.

SOUTHEAST WINDS THIS MORNING WILL USHER LOW LEVEL MOISTURE RIGHT
BACK INTO THE AREA...AND PLENTY OF SUNSHINE...ESPECIALLY ACROSS THE
SOUTHWEST SECTIONS OF THE CWA...WILL SET THE STAGE FOR THUNDERSTORM
DEVELOPMENT THIS AFTERNOON. A SFC LOW WILL SLIDE SOUTHWARD ACROSS
THE PANHANDLE THIS AFTERNOON WITH CAPE VALUES OF 2000-3000 J/KG JUST
TO THE EAST OF THE LOW.  WINDS WILL BACK JUST AHEAD OF THE LOW
PRESSURE...ESPECIALLY ALONG THE PLATTE RIVER VALLEY WHICH WILL HELP
OVERALL SHEAR PROFILES. THEREFORE...HAVE INCLUDED 50-60 POPS ACROSS
THE FAR SOUTHEAST ALONG WITH SEVERE WORDING...AND THEN TAPERING BACK
TO 30 POPS NORTH AND WEST. THE LOW PRESSURE AND ASSOCIATED FRONT MOVE
QUICKLY SOUTHWARD THIS EVENING WITH PRECIP ENDING ACROSS THE CWA BY
MIDNIGHT.

TEMPERATURES WILL CONTRAST SIGNIFICANTLY ACROSS THE CWA TODAY WITH
THE NORTHEAST ONLY REACHING THE LOWER 80S WITH QUITE A BIT OF CLOUD
COVER AND SOME EARLY SHOWERS/THUNDERSTORMS. THE SOUTHWEST WILL SEE
MOSTLY SUNNY SKIES MUCH OF THE DAY SO WILL BE ABLE TO WARM UP
NICELY WITH TEMPERATURES REACHING THE UPPER 90S.  TEMPERATURES ON
TUE WILL BE 10 TO 15 DEGREES COOLER AS H8 TEMPS ONLY IN THE TEENS.
SOME OF THE COOLING...MAINLY IN THE WEST...WILL BE OFFSET BY THE
STRONG JULY SUN.

A RIDGE SLOWLY BUILDS BACK INTO THE AREA BUT SFC LOW PRESSURE
DEVELOPING ON THE LEE SIDE OF THE ROCKIES BY LATE IN THE WEEK WILL
BRING A CHANCE OF SHOWERS/THUNDERSTORMS BACK INTO THE CWA.

.LBF...NONE.

DDB

NEZ004>010-022>029-035>038-056>059-069>071-094-221100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1144 AM CDT MON JUL 21 2003

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

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE WEATHER OVER THE ENTIRE OUTLOOK
AREA. THE AREA AT GREATEST RISK FOR LARGE HAIL WILL BE AN AREA
BOUNDED SOUTH OF A LINE FROM BROKEN BOW TO MULLEN TO OGALLALA TO
IMPERIAL.

WINDS IN THE MID LEVELS OF THE ATMOSPHERE WILL BE STRONGER THAN
NORMAL TODAY AS SURFACE LOW PRESSURE DEEPENS INTO SOUTHWEST NEBRASKA
BY LATE AFTERNOON. THIS WILL CREATE FAVORABLE WIND PROFILES AS MOIST
AND UNSTABLE AIR IS DRAWN INTO THE OUTLOOK AREA. ANY THUNDERSTORMS
WHICH DEVELOP WILL BE CAPABLE OF QUICKLY BECOMING SEVERE PRODUCING
LARGE HAIL GREATER THAN 1 INCH IN DIAMETER AND DAMAGING WINDS.

BY THIS EVENING...THUNDERSTORMS MAY CONTINUE TO BE SEVERE
EARLY...MAINLY SOUTH OF A LINE FROM HAYES CENTER...TO NORTH
PLATTE...TO OCONTO. BY LATE EVENING THUNDERSTORM ACTIVITY IS
EXPECTED TO END ACROSS THE OUTLOOK AREA.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

DRIER AIR WILL MOVE INTO THE OUTLOOK AREA ON TUESDAY AND WEDNESDAY
THUS DIMINISHING THE CHANCES FOR THUNDERSTORMS. BY
THURSDAY...MOISTURE WILL RETURN TO THE OUTLOOK AREA AS A SURFACE
FRONT AND DISTURBANCE ALOFT PROVIDE THE FOCUS FOR THE CHANCE OF
THUNDERSTORMS DURING THE LATE AFTERNOON AND EVENING HOURS. A
CONTINUED CHANCE FOR THUNDERSTORMS WILL EXIST FOR FRIDAY AND
SATURDAY AS A SURFACE FRONT STALLS OUT TO OUR SOUTH AND REMAINS
NEARLY STATIONARY WITH MOIST AND UNSTABLE AIR RESIDING OVER THE
OUTLOOK AREA. DRY AND STABLE CONDITIONS ARE AGAIN EXPECTED SUNDAY AS
HIGH PRESSURE BUILDS INTO THE OUTLOOK AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY EVENING.

POWER