Severe Thunderstorm Warning 23, NWS Cheyenne, WY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
248 PM MDT SUN MAY 7 2000

IT LOOKS LIKE AN UNSETTLED PERIOD WITH A BROAD CYCLONIC TROF OVER
THE WRN US THRU THE PD. SOME DIFFERENCES WITH THE SHORT WAVES AND
SFC FEATURES BETWEEN THE MODELS AND AM GOING WITH THE AVN. AVN SEEMS
TO HAVE A BETTER HANDLE ON SFC FEATURES AND RH FIELDS. IN THE SHORT
TERM...SHORT WAVE MOVING THRU WRN WY WL CONT E THIS AFT. SFC LOW WL
DVLP OVR SE WY WITH UPSLP FLOW AT THE SFC. DEWPTS IN THE UPPER 40S
TO MID 50S AND AMS IS DESTABILIZING...ESPECIALLY OVR THE SW NEB
PANHANDLE. COOLER AND MORE STABLE AIR MOVES S INTO THE AREA
OVERNIGHT BRINGING AN END TO TSTMS...BUT SOME LOWER CLDS AND LIGHT
SHOWERS ARE STILL POSSIBLE. NEXT SIG SHORT WAVE MOVES INTO THE AREA
LATE MON AND EXITS TUESDAY WITH LEE TROF SETTING UP THRU ERN WY
TUES AFT.  MAINLY EXPECT MORNING SHOWERS WEST THEN DRY...WARMER AND
BREEZY CONDS DURING THE AFT. WL KEEP A LOW SCT POP IN THE ERN ZONES
FOR TUES. WL LEAN TOWARD THE FAN GUID POPS. TEMP WISE...WL USE A
BLEND OF THE FWC/FAN GUID. COOLER MON AND A LITTLE WARMER ON TUES.

EXTENDED DISCUSSION...
ZONAL FLOW FCST TO BUCKLE OVR WRN U.S. WITH TROF MOVG INTO THE
W COAST BY FRI.  AFTER THAT...PIECES OF ENERGY WL EJECT NE OUT
OF LARGER SCALE TROF THRU THE WEEKEND.  THE TROF WAS FRTHR E ON
THE NEW MRF THAN ITS PREV RUN.  WITH EITHER RUNS TIMING...STILL
LOOKS TO BE A THREAT OF SHWRS AND TSTMS STARTING UP AGN THU AFTN
WITH THE CHC INCRSG THRU SUN.  MOR WDSPRD PCPN PER NCEP ENSEMBLE
SHUD BE TO OUR N DRG THAT TIME.  SVR WX LOOKS LIKE A PSBLTY THU
AFTN AND EVE AND MAYBE AGN FRI AFTN AND EVE.

.CYS...
WY...NONE.
NE...NONE.

STARK/WEILAND

NEZ001>003-019>021-054-055-WYZ059>070-072300-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
1028 AM MDT SUN MAY 7 2000

SPOTTER ACTIVATION FOR SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE MAY BE NEEDED THIS AFTERNOON AND EVENING.

DISCUSSION...A FRONT REMAINS NEARLY STATIONARY THROUGH NORTHERN
COLORADO AND WESTERN NEBRASKA.  MOIST AND UNSTABLE AIR ACROSS
THE SOUTHEAST WYOMING PLAINS AND IN WESTERN NEBRASKA WILL BE THE AREA
OF CONCERN FOR THUNDERSTORM DEVELOPMENT THIS AFTERNOON.  AN UPPER
LEVEL DISTURBANCE OVER WESTERN WYOMING WILL MOVE EAST ACROSS THE AREA
THIS AFTERNOON PROVIDING A SOURCE OF LIFT FOR THUNDERSTORM
DEVELOPMENT.  A DECK OF HIGH CLOUDS WILL GRADUALLY MOVE OFF TO THE
EAST...ALLOWING FOR A BIT MORE SUNSHINE AND HEATING AT THE SURFACE.
THUNDERSTORMS SHOULD BEGIN TO DEVELOP OVER THE MOUNTAINS OF SOUTHEAST
WYOMING BY EARLY AFTERNOON AND SPREAD EAST INTO THE PLAINS THROUGH
THIS EVENING.  THE PRIMARY THREAT WITH THUNDERSTORMS THIS AFTERNOON
WILL BE LARGE HAIL...BUT ISOLATED TORNADOES AND WIND GUSTS IN EXCESS
OF 60 MPH ARE ALSO POSSIBLE.  A COOLER AIRMASS WILL GRADUALLY SPREAD
SOUTH INTO THE AREA LATER THIS EVENING ENDING THE THREAT OF SEVERE
WEATHER.

STARK
WCJIN-WYNE-WYSE

WYZ060-068-070-NEZ001>003-019>021-054-055-080200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
221 PM MDT SUN MAY 7 2000

...A TORNADO WATCH HAS BEEN ISSUED FOR PARTS OF EAST CENTRAL AND
SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE THROUGH 8 PM...

THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH UNTIL 8 PM
FOR PARTS OF EAST CENTRAL AND SOUTHEAST WYOMING AND THE NEBRASKA
PANHANDLE.  THE WATCH INCLUDES THE CITIES OF LUSK...TORRINGTON AND
PINE BLUFFS...BUT DOES NOT INCLUDE CHEYENNE.

A WATCH FOR THAT AREA MEANS THAT WEATHER CONDITIONS ARE PRESENT FOR
THE FORMATION OF SEVERE THUNDERSTORMS WHICH MAY PRODUCE TORNADOES.

AT 215 PM...THUNDERSTORMS WERE LOCATED OVER EASTERN CONVERSE
COUNTY...AS WELL AS 10 MILES WEST OF GLENDO AND 20 MILES NORTHEAST
OF CHEYENNE.  THE STORMS SHOULD CONTINUE TO DEVELOP AND MOVE TO
THE NORTHEAST AT 30 MPH.

PEOPLE IN THE WATCH AREA SHOULD BE ALERT TO THE POSSIBILITY OF
SEVERE THUNDERSTORMS AND EVEN TORNADOES THROUGH THE EARLY EVENING.
WHEN A THUNDERSTORM APPROACHES...GO TO YOUR SAFE SHELTER AND AWAY
FROM WINDOWS.

WEILAND