Severe Thunderstorm Warning 34, NWS Cheyenne, WY

ZCZC CYSWRKAFD ALL
TTAA00 KCYS 181738

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
125 PM MDT SAT MAY 31 2003

SHORT TERM...18Z SFC CHART SHOWS HIGH OVER DAKOTAS PRODUCING S/SE
FLOW EAST OF THE MOUNTAINS.  DEW POINTS ARE IN THE 50S EAST OF THE
RANGE AND MOST LOCATIONS HAVE HAD LOW CLOUD CEILINGS THIS MORNING
BUT ARE NOW BURNING OFF.  REGARDLESS LOTS OF LOW LEVEL MOISTURE
AVAILABLE.  88D STARTING TO SHOW RETURNS TO THE SOUTH IN COLORADO.
8H PATTERN SHOWS STRONG THERMAL PACKING ACROSS THE CWA REFLECTING
QUASI-STATIONARY FRONT. 7H HAS SERIES OF SHORT WAVES MOVING THROUGH
THE FLOW.

LITTLE CHANGE IN FORECAST FOR THE NEXT 36 HOURS AS MODELS INDICATE
TRANSITORY 5H RIDGE MOVING OVERHEAD TONIGHT AND BY 18Z SUNDAY
ANOTHER TROF AND ASSOCIATED PVA WILL AGAIN BE AFFECTING THE AREA.
THIS EVENING GOOD SHEER IN EASTERN CWA ALONG WITH HIGH CAPES AND
LOW LIS SO SHOULD SEE CONVECTIVE ACTIVITY FIRING UP SOON.  LOW
CLOUDS SHOULD DEVELOP AGAIN OVER NIGHT IN EASTERN AREAS AND SO WITH
THE NEXT WAVE MORE THUNDERSTORMS SHOULD DEVELOP AGAIN WITH THE
STRONGEST STORMS PROBABLY FURTHER EAST MAINLY IN THE PANHANDLE.

LONG TERM...PERIOD CONTINUES TO BE DOMINATED BY NORTHWESTERLY
FLOW WITH SHORT WAVE TROUGHS/RIDGES MOVING THROUGH. FLOW BECOMES
MORE WESTERLY. AVN HAS SHARPENING TROUGH DROPPING OUT OF MT
WED NIGHT WITH THICKNESSES OVER CWA DROPPING BELOW 552 BY 12 UTC
THU. WOULD EXPECT SOME MODERATION OF THIS DEGREE OF COOLING
ON MODEL FORECASTS NEXT FEW DAYS BUT STILL DISTINCT CHANGE IF
TROUGH REMAINS AS STRONG. LAR WILL HAVE AT LEAST COUPLE MORNINGS
NEAR FREEZING AT MID WEEK...POSSIBLY RWL.  NEED TO CHANGE SURFACE
PATTERN AND FLUSH LOW LEVEL MOISTURE TO GET OUT OF RECURRING SLIGHT
RISK AND THIS DOESN/T FEASIBLE TIL TUE. BOTH ETA/AVN DRY LATE SUN
NIGHT/EARLY MON. GFS HAS IT DRYING OUT AGAIN NEXT WEEKEND AS UPPER
FLOW RETURNS TO NORTHWESTERLY. OTHERWISE SCATTERED/WIDELY SCATTERED
LATE DAY POPS PREVAIL.

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

GRIFFITH/COX

NEZ001>003-019>021-054-055-WYZ059>070-011200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
952 AM MDT SAT MAY 31 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEASTERN WYOMING AND THE
WESTERN NEBRASKA PANHANDLE.

.DAY ONE...TODAY AND TONIGHT

DAYTIME HEATING WILL COMBINE WITH ABUNDANT LOW LEVEL MOISTURE TO
PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS AGAIN THIS AFTERNOON
WITH THE INITIAL FORMATION OVER AND NEAR THE MOUNTAINS OF SOUTHEAST
WYOMING.  THE STORMS WILL THEN MOVE SLOWLY SOUTHEAST OVER THE PLAINS
AND INTO THE PANHANDLE LATER THIS AFTERNOON AND TONIGHT.  A FEW
ISOLATED STORMS COULD BECOME SEVERE WITH LARGE HAIL AND GUSTY WINDS
THE PRIMARY THREAT. SOME STORMS MAY PRODUCE BRIEF PERIODS OF HEAVY
RAIN AND COULD CAUSE LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

LITTLE CHANGE IS SEEN IN THE OVERALL WEATHER PATTERN FOR SUNDAY WITH
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP IN THE
AFTERNOON.  THE CHANCE FOR A FEW STORMS TO BECOME SEVERE WILL STILL
EXIST...MAINLY ACROSS EXTREME SOUTHEAST WYOMING AND THE NEBRASKA
PANHANDLE.  SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO
WEDNESDAY WITH MOISTURE REMAINING ACROSS THE REGION BUT THE SEVERE
THREAT WILL DIMINISH AS THE AIR BECOMES COOLER AND LESS UNSTABLE.
BY THE END OF THE WEEK DRIER CONDITIONS WILL RETURN TO THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED LATER THIS AFTERNOON AND EVENING.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

GRIFFITH