Severe Thunderstorm Warning 28, NWS Riverton, WY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
258 PM MDT THU JUN 24 2004

.TONIGHT THROUGH SUNDAY...
SCATTERED TSTMS HAVE FIRED ACROSS NORTHWEST AND CENTRAL WYOMING...
UNDER NORTHWEST FLOW ALOFT. WILL GO WITH CHC POPS POPS ACROSS
MUCH OF CWFA THIS EVENING. UPPER LEVEL NORTHWEST FLOW FRIDAY AND
SATURDAY WITH LOW LEVEL EASTERLY FLOW MAINLY EAST OF THE DIVIDE.
UPPER LEVEL RIDGE BEGINS BUILDING ACROSS WY ON SUNDAY. LOOKS LIKE
SCATTERED AFTERNOON AND EVENING TSTMS ACROSS MAINLY THE CENTRAL AND
NORTHWEST CWFA FOR FRIDAY AND SATURDAY DUE TO GOOD INSTABILITY AND
SOME 7-3H VERTICAL MOTION. ALSO...THE SHEAR PROFILE FAVORS A
FEW SEVERE STORMS POSSIBLE...ESPECIALLY ON FRIDAY. WILL GO WITH A
DRIER FORECAST ON SUNDAY DUE TO UPPER RIDGE BUILDING...HOWEVER
ENOUGH INSTABILITY AND MOISTURE AROUND THAT SOME AREAS
MIGHT SEE SCATTERED TSTMS...ESPECIALLY ACROSS CENTRAL AND
NORTHWEST CWFA. WILL LET MID SHIFT DECIDE IF THEY WANT TO BUMP UP TO
CHC POPS FOR SUNDAY.

.SUNDAY NIGHT THROUGH WEDNESDAY...
LARGE UPPER LEVEL LOW PRESSURE CENTER SETS UP OVER PACIFIC NORTHWEST
COASTAL AREA WITH WEAK RIDGE OVER WYOMING.  SERIES OF WEAK SHORT
WAVE TROUGHS ALOFT WILL EJECT NORTHEAST FROM GREAT BASIN IN
SOUTHWEST FLOW BETWEEN PACIFIC NORTHWEST LOW AND RIDGE OVER WYOMING.
CANADIAN SURFACE COLD FRONT REMAINS HUNG UP IN WESTERN MOUNTAINS
PROVIDING WEAK UPSLOPE FLOW EAST OF CONTINENTAL DIVIDE KEEPING
HIGHER LOW LEVEL MOISTURE IN PLACE.  COMBINATION OF WEAK SHORT WAVE
TROUGHS WITH COLD FRONT AND AVAILABLE LOW LEVEL MOISTURE WILL KEEP
SCATTERED SHOWERS AND THUNDERSTORMS OVER THE AREA.  EXPECT
CONVECTION TO BE MAINLY THERMALLY DRIVEN WITH LATE AFTERNOON AND
EARLY EVENING MAXIMUM.  NOT MUCH CHANGE IN PATTERN EXPECTED FROM
SUNDAY TO MONDAY AND INTO TUESDAY.  AND HAVE ADDED SLIGHT CHANCE OF
THUNDERSTORMS AFTERNOON AND EVENING ON MONDAY WITH DECREASING
MAINLY MOUNTAIN COVERAGE ON TUESDAY.  COLD FRONT EXPECTED TO LIFT
NORTHEAST ON TUESDAY NIGHT AS SOUTHWEST FLOW INCREASES AND BRINGS
SOME DRIER AIR INTO THE AREA.  LEFT WEDNESDAY DRY BUT MAY SEE
CONVECTION ACROSS NORTH AND EAST DEPENDING ON HOW FAR COLD FRONT
LIFTS NORTHEAST.  GRADUAL WARMING TREND THROUGH THE PERIOD.  WARMED
TEMPERATURES SLIGHTLY MONDAY THROUGH WEDNESDAY.  OVERALL EXTENDED
MODELS IN GOOD AGREEMENT WITH UPPER LEVEL MASS FIELDS THROUGH THE
PERIOD.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

MC/C.BAKER

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
1017 AM MDT THU JUN 24 2004

WYZ001>020-022>030-251200-
ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST-
BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY-
TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN-
WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
YELLOWSTONE NATIONAL PARK-
1017 AM MDT THU JUN 24 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS ARE EXPECTED TO DEVELOP EARLY THIS AFTERNOON OVER
WESTERN WYOMING. THESE STORMS WILL INCREASE IN COVERAGE AS THE
AFTERNOON WEARS ON AND THEN SPREAD ACROSS THE LOWER ELEVATIONS OF
CENTRAL WYOMING. A FEW OF THESE STORMS MAY BECOME SEVERE PRODUCING
HAIL UP TO QUARTER SIZE...WIND GUSTS TO 60 MPH...VERY HEAVY RAIN AND
DANGEROUS LIGHTNING. THE BEST CHANCE FOR SEVERE THUNDERSTORMS LATER
THIS AFTERNOON AND EVENING WILL BE FROM THE WIND RIVER BASIN TO
NATRONA COUNTY AND ALSO IN THE SOUTH BIG HORN BASIN AND CODY
FOOTHILLS. THE THUNDERSTORMS ACROSS CENTRAL WYOMING ARE EXPECTED TO
CONTINUE WELL INTO THE EVENING HOURS BEFORE DIMINISHING AFTER
MIDNIGHT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

ANOTHER ACTIVE THUNDERSTORM DAY IS EXPECTED FRIDAY AFTERNOON AND
EVENING...ESPECIALLY ACROSS CENTRAL AND WESTERN WYOMING. A FEW OF THE
STRONGER STORMS MAY CONTAIN QUARTER SIZE HAIL...WIND GUSTS TO 60
MPH...VERY HEAVY RAIN AND DANGEROUS LIGHTNING. LITTLE CHANGE IS
EXPECTED SATURDAY. THE CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
WILL PERSIST THROUGH TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE ASKED TO REPORT LARGE HAIL AND STRONG WINDS THIS
AFTERNOON AND TONIGHT.

SKRBAC