Special Weather Statement, NWS Cheyenne, WY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
206 PM MDT FRI AUG 5 2011

.SHORT TERM...TONIGHT THROUGH SUNDAY...

MAIN CONCERN IN THE SHORT TERM IS THE CHANCE OF SEVERE WEATHER.
HOWEVER AT THIS TIME CONVECTION A LITTLE SLOW IN GETTING STARTED.

18Z SURFACE ANALYSIS SHOWED LOW OVER NORTH CENTRAL WYOMING WITH A
BOUNDARY STRETCHING TO THE SOUTHEAST AND STORMS HAVE BEEN FIRING
IN THIS AREA MOST OF THE MORNING. RIVERTON RADAR STARTING TO SHOW
SOME RETURNS IN RESPONSE TO A SHORT WAVE MOVING OUT OF IDAHO. THIS
FEATURE SHOULD TRIGGER THUNDERSTORMS IN OUR CWA LATER TODAY.

LAPS DATA SHOWING CAPES OVER 2000 IN NORTHERN PANHANDLE AS WELL AS
LI'S OF -6. DEW POINTS IN THIS AREA ARE OVER 60 SO THERE IS PLENTY
OF MOISTURE AND INSTABILITY TO GET THINGS GOING.

SECONDARY CONCERN THIS AFTERNOON IS FIRE WEATHER AS DRY AIR
WORKING ITS WAY INTO THE WESTERN AND NORTHERN PORTIONS OF THE CWA.
ONLY THING HOLDING BACK THE HIGHLIGHTS ARE WINDS NOT REACHING
CRITERIA.

LOOKING AT THE REST OF THE WEEKEND SHOWS TYPICAL SUMMERTIME
WEATHER WHERE AFTERNOON STORMS CANNOT BE RULED OUT. HIGHS EXPECTED
TO BE GENERALLY IN THE 80S AND 90S WITH LOWS NEAR NORMAL.

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
PERSISTENT WEATHER PATTERN EXPECTED OVER THE REGION THROUGH THE
WEEK WITH WESTERLY UPPER FLOW ATOP UPPER HIGH SITUATED ACROSS THE
SOUTH AND SOUTHWESTERN PART OF THE COUNTRY. MONSOONAL FLOW WILL BE
CUT OFF FROM THE CWA FOR THE MOST PART WITH WEAK UPPER RIDGING THUS
AFTERNOON AND EVENING CONVECTION SHOULD BE MORE LIMITED...ENHANCED
PERIODICALLY BY ANY WEAK AND HARD TO TIME IMPULSES THAT CROSS THE
REGION. BEST CHANCE FOR CONVECTION WILL BE OVER THE PANHANDLE
WHERE A WEAK FRONTAL BOUNDARY IS LIKELY TO MEANDER ACROSS FROM
TIME TO TIME. OTHERWISE EXPECT WARM TEMPERATURES TO CONTINUE WITH
LITTLE CHANGES THROUGH THE WEEK.

&&

.AVIATION...USUAL SUMMER TIME PATTERN WILL CONTINUE THROUGH THE
WEEKEND WITH AFTERNOON CONVECTION EXPECTED. SOME PATCHY FOG AND
LOW CEILINGS WILL BE POSSIBLE AROUND SUNRISE AT THE PANHANDLE
LOCATIONS ON SATURDAY MORNING.

&&

.FIRE WEATHER...DRY CONDITIONS WILL BE OBSERVED ACROSS THE WESTERN
AND NORTHERN PORTIONS OF THE DISTRICT AND BEAR CLOSE MONITORING.
RELATIVE HUMIDITY MAY REACH CRITICAL VALUES BUT WINDS SHOULD STAY
JUST BELOW NEEDED VALUES FOR HIGHLIGHTS.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

SHORT TERM/AVIATION/FIRE WEATHER...GRIFFITH
LONG TERM...RE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
1035 AM MDT FRI AUG 5 2011

WYZ101>119-061130-
CONVERSE COUNTY LOWER ELEVATIONS-NIOBRARA COUNTY-
NORTH LARAMIE RANGE-FERRIS/SEMINOE/SHIRLEY MOUNTAINS-
SHIRLEY BASIN-CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
EAST PLATTE COUNTY-GOSHEN COUNTY-CENTRAL CARBON COUNTY-
NORTH SNOWY RANGE FOOTHILLS-SOUTHWEST CARBON COUNTY-
SIERRA MADRE RANGE-UPPER NORTH PLATTE RIVER BASIN-SNOWY RANGE-
LARAMIE VALLEY-SOUTH LARAMIE RANGE-SOUTH LARAMIE RANGE FOOTHILLS-
CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY-
1035 AM MDT FRI AUG 5 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP MAINLY THIS
AFTERNOON AND THIS EVENING. A FEW THUNDERSTORMS ACROSS EAST CENTRAL
WYOMING MAY BECOME SEVERE PRODUCING LARGE HAIL AND DAMAGING WINDS.
THUNDERSTORM ACTIVITY WILL DISSIPATE BY SUNSET.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

ISOLATED THUNDERSTORMS WILL BE POSSIBLE INTO NEXT WEEK AND WILL
BE MAINLY CONFINED TO AREAS EAST OF THE MOUNTAINS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED IN EAST CENTRAL WYOMING THIS
AFTERNOON AND EVENING.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND
CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT...
HTTP://WEATHER.GOV/CHEYENNE

NEZ002-003-019>021-054-055-095-096-061130-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-
1035 AM MDT FRI AUG 5 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA
PANHANDLE.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND CONTINUE
THIS EVENING. A FEW THUNDERSTORMS ACROSS THE NORTHERN AND CENTRAL
NEBRASKA PANHANDLE MAY BECOME SEVERE PRODUCING LARGE HAIL AND
DAMAGING WINDS. THUNDERSTORM ACTIVITY WILL DISSIPATE BY SUNSET.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

ISOLATED AFTERNOON AND EVENING THUNDERSTORMS WILL BE POSSIBLE
INTO NEXT WEEK.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED IN THE NORTHERN AND CENTRAL
NEBRASKA PANHANDLE THIS AFTERNOON AND EVENING.

&&

THIS PRODUCT...ALONG WITH OTHER WEATHER...HYDROLOGIC...AND
CLIMATE INFORMATION IS AVAILABLE ON THE WEB AT...
HTTP://WEATHER.GOV/CHEYENNE

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
215 PM MDT FRI AUG 5 2011

WYZ103-107-108-052115-
EAST PLATTE COUNTY WY-GOSHEN COUNTY WY-NORTH LARAMIE RANGE WY-
215 PM MDT FRI AUG 5 2011

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN PLATTE AND NORTHWESTERN
GOSHEN COUNTIES UNTIL 315 PM MDT...

AT 212 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR SIBLEY PEAK...OR 25 MILES SOUTHEAST OF
DOUGLAS...MOVING EAST AT 25 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE...
  SIBLEY PEAK...
  GLENDO...
  GLENDO RESERVOIR...
  RAWHIDE BUTTES...

THIS INCLUDES INTERSTATE 25 IN WYOMING BETWEEN MILE MARKERS 102 AND
116.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 4260 10444 4233 10444 4238 10520 4256 10520
TIME...MOT...LOC 2015Z 270DEG 20KT 4247 10508

GRIFFITH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
235 PM MDT FRI AUG 05 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0232 PM     HAIL             3 E GLENDO              42.50N 104.97W
08/05/2011  E0.25 INCH       PLATTE             WY   TRAINED SPOTTER

            HEAVY RAIN

&&

GRIFFITH

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHEYENNE WY
236 PM MDT FRI AUG 05 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0235 PM     HAIL             GLENDO                  42.50N 105.03W
08/05/2011  E0.25 INCH       PLATTE             WY   TRAINED SPOTTER

            GLENDO MARINA

&&

GRIFFITH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
348 PM MDT FRI AUG 5 2011

NEZ054-052245-
KIMBALL NE-
348 PM MDT FRI AUG 5 2011

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL KIMBALL COUNTY UNTIL 445
PM MDT...

AT 345 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM NEAR OLIVER RESERVOIR...OR 12 MILES WEST OF
KIMBALL...MOVING EAST AT 15 MPH.

HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

THIS STORM WILL BE NEAR...
OLIVER RESERVOIR AROUND 400 PM MDT.
KIMBALL AROUND 435 PM MDT.
BENNETT RESERVOIR AROUND 445 PM MDT.

THIS INCLUDES INTERSTATE 80 IN NEBRASKA BETWEEN MILE MARKERS 4 AND
31.

IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.

TORRENTIAL RAIN...WHICH MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND
UNDERPASSES...IS ALSO LIKELY. DO NOT DRIVE YOUR VEHICLE ON A FLOODED
ROADWAY.

&&

LAT...LON 4129 10343 4102 10354 4114 10401 4133 10396
TIME...MOT...LOC 2148Z 284DEG 12KT 4122 10387

JAMSKI