Hail and Damaging Wind in Wyoming, June 18, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
230 PM MDT TUE JUN 18 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 230 PM MDT TUE JUN 18 2013

FORECAST CHALLENGES DEAL WITH SEVERE THUNDERSTORM CHANCES
TODAY...FOLLOWED BY FIRE WEATHER CONCERNS THROUGH FRIDAY. PLEASE
REFER TO FIRE WEATHER SECTION BELOW FOR FIRE WEATHER DETAILS.

CURRENTLY...CONVECTION BEGINNING TO DEVELOP OUT WEST OF THE
LARAMIE RANGE. LATEST WATER VAPOR IMAGERY SHOWING A SUBTLE
SHORTWAVE MOVING INTO SOUTHWESTERN WYOMING THIS AFTERNOON...WHICH
IS MOST LIKELY AIDING IN EARLIER DEVELOPMENT OF TSTMS OUT WEST. A
PRETTY MOIST ATMOSPHERE IN PLACE EAST OF THE LARAMIE RANGE WITH
DEWPOINTS IN THE UPPER 40S JUST EAST OF THE LARAMIE RANGE HERE AT
CHEYENNE. FURTHER EAST IN THE PANHANDLE...LOW TO MID 50 TDS ARE
BEING REPORTED. LATEST SPC MESOANALYSIS SHOWING CAPES OVER EXTREME
SOUTHEASTERN WYOMING AND SOUTHERN PANHANDLE AROUND 600-1000 J/KG
AND CONVECTIVE INHIBITION AT ZERO. STILL CAPPED SOME OVER THE
NORTHERN PANHANDLE AND NIOBRARA COUNTIES WITH ROUGHLY 50-75
J/KG...BUT THIS SHOULD ERODE AWAY AS TEMPERATURES CONTINUE TO
CLIMB THIS AFTERNOON.

THINKING A REPEAT OF YESTERDAY CONVECTION WISE...THOUGH COULD BE MORE
WIDESPREAD WITH THE ASSISTANCE OF THAT LITTLE SHORTWAVE MOVING
THROUGH THE AREA. SEVERE THUNDERSTORMS SHOULD MOVE OFF THE LARAMIE
RANGE INTO THE BETTER ENVIRONMENT TO PRODUCE LARGE HAIL AND
DAMAGING WINDS. SHORTWAVE COMES THROUGH EASTERN WYOMING BY 00Z
THIS AFTERNOON. LATEST HRRR COMPOSITE REFLECTIVITY SHOWING
INDIVIDUAL CELLS DEVELOPING OVER THE LARAMIE RANGE...THEN
CONGEALING INTO A LINE NEAR THE WYOMING/NEBRASKA BORDER AFTER 00Z.

THUNDERSTORMS LOOK TO COME TO AN END MID EVENING AS THE SHORTWAVE
MOVES EAST INTO WESTERN NEBRASKA AFTER 03Z OR SO. UPPER RIDGE AXIS
SHIFTS EAST AS WELL...WITH WEST TO SOUTHWEST WINDS RETURNING TO
CARBON AND ALBANY COUNTIES AFTER MIDNIGHT.

WEDNESDAY LOOKS LIKE A VERY DRY AND WINDY DAY AS 700MB WINDS
INCREASE SIGNIFICANTLY. GFS SHOWING THESE WINDS CLIMBING TO NEAR
40KTS WEST OF THE LARAMIE RANGE. GOOD MID LEVEL WARMING AS WELL
WITH 700MB TEMPERATURES CLIMBING FROM +10C THIS AFTERNOON TO +16C
WEDNESDAY AFTERNOON. LEESIDE TROUGH STILL HANGS OUT OVER THE
PANHANDLE WEDNESDAY AFTERNOON...SO ISOLATED TO WIDELY SCATTERED
THUNDERSTORMS STILL A GOOD BET OUT THAT WAY.

FOR THURSDAY...UPPER LOW CURRENTLY OFF THE WASHINGTON STATE COAST
MOVES INLAND TO THE IDAHO PANHANDLE. THIS WILL KEEP WINDS STRONG
OVER OUR CWFA...BUT 700MB TEMPERATURES COOL SOME...DOWN TO +10 TO
+12C. SO THURSDAY SHOULD BE A LITTLE COOLER OVER WEDNESDAY BY A
FEW DEGREES.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 230 PM MDT TUE JUN 18 2013

REX BLOCKING PATTERN ACROSS WESTERN NOAM WILL BREAK DOWN EARLY IN
THE PERIOD AS THE MEANDERING PACNW CLOSED LOW FILLS AND MOVES OUT
ONTO THE NRN ROCKIES/PLAINS. THE DEPTH AT WHICH IT DOES SO WILL
BE THE MAIN FORECAST CHALLENGE AND WILL CARRY RESIDUAL IMPACTS TO
SENSIBLE WEATHER.

ON FRIDAY...UPPER LOW WILL SWING FROM THE IDAHO PANHANDLE INTO
WESTERN MONTANA. 12Z OPERATIONAL GFS AND ECMWF ARE FAIRLY SIMILAR
IN ITS PLACEMENT NR THE ID/MT STATELINE BY EARLY SATURDAY. WEAK
INSTABILITY ACROSS EAST CENTRAL WYOMING AND THE NORTHERN NEBRASKA
PANHANDLE. SO HAVE CONFINED CONVECTIVE CHANCES THERE. THIS LOW
PRESSURE AREA WILL SWING THROUGH MONTANA DURING THE DAY ON
SATURDAY. THE EASTERN PLAINS SHOULD SEE ANOTHER CONVECTIVE DAY ON
SATURDAY AS LLVL MOISTURE DEEPENS AND BACKS UP INTO THE EASTERN
PLAINS. THIS WILL RESULT IN CAPE VALUES THAT WILL ONCE AGAIN CLIMB
ABOVE 2000 J/KG. SATURDAY LOOKS TO PROVIDE THE BEST SEVERE WEATHER
POTENTIAL THROUGH THE PERIOD.

BY SUNDAY AND MONDAY...THE UPPER LOW EJECTS FROM THE DAKOTAS
NORTHEAST TOWARDS HUDSON BAY. THIS SHOULD BRING AN END TO
CONVECTIVE ACTIVITY AND BEGIN TO HEIGHTEN FIRE WEATHER CONCERNS
FOR LATE IN THE WEEKEND/EARLY NEXT WEEK. FLOW WILL BECOME
INCREASINGLY SOUTHWESTERLY AS WELL...WHICH WILL AID IN THE
SURFACING OF GUSTIER WINDS ALOFT.

H7 TEMPERATURES WILL RANGE BETWEEN 13 AND 15C THROUGH THE UPCOMING
WEEKEND AND INCREASE TO 17C BY TUESDAY. HIGH TEMPERATURES WILL
REACH GENERALLY IN THE 80S AND LOW 90S THROUGH THE PERIOD...WITH
EVEN SOME MID AND POTENTIALLY UPPER 90S OUT ON THE FAR EASTERN
PLAINS BY EARLY NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1029 AM MDT TUE JUN 18 2013

ANOTHER ROUND OF THUNDERSTORMS THIS AFTERNOON EXPECTED FOR
AIRPORTS FROM KLAR EAST THROUGH THE PANHANDLE. USING THE LATEST
HRRR GUIDANCE...TRIED TO NARROW TIMING OF THUNDERSTORM ONSET.
INITIALLY A FEW CELLS AROUND KLAR AND KCYS...BUT THEN FORMING A
LINE ONCE THE STORMS GET INTO THE PANHANDLE. TIMING LOOKS TO BE
EARLY TO MID AFTERNOON AT KLAR AND KCYS...THEN THE LINE DEVELOPING
AND MOVING THROUGH THE PANHANDLE SHORTLY AFTER 00Z. DO NOT THINK
WE WILL HAVE TO DEAL WITH LOW CEILINGS TONIGHT AS WINDS TURN MORE
DOWNSLOPING OFF THE LARAMIE RANGE TONIGHT.

&&

.FIRE WEATHER...
ISSUED AT 230 PM MDT TUE JUN 18 2013

ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS WEDNESDAY
THROUGH FRIDAY AS HIGH PRESSURE MOVES OFF TO THE EAST AND
SOUTHWEST TO WEST WINDS RETURN TO THE AREA. ZONES ALONG AND WEST
OF THE LARAMIE RANGE LOOK TO SEE WIDESPREAD WINDS OF 20 TO 30 MPH
SUSTAINED WITH GUSTS TO 40 MPH BEGINNING MID MORNING WEDNESDAY
THAT WILL PERSIST THROUGH FRIDAY. WINDIEST TIME PERIODS LOOK TO BE
LATE MORNING THROUGH SUNSET. AFTERNOON HUMIDITIES OUT WEST WILL
FALL TO 5 TO 10 PERCENT WITH POOR OVERNIGHT RECOVERIES WITH THESE
STRONG WINDS. EAST OF THE LARAMIE RANGE...WINDS WILL BE LESS WITH
HIGHER AFTERNOON HUMIDITIES. SINCE ALL ZONES ARE STILL REPORTING
FUELS AS NOT READY FOR RAPID FIRE GROWTH...NO FIRE WEATHER
HEADLINES ARE FORECAST FOR TOMORROW OR FRIDAY AT THIS TIME.

&&

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

SHORT TERM...CLAYCOMB
LONG TERM...HAHN
AVIATION...CLAYCOMB
FIRE WEATHER...CLAYCOMB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
1130 AM MDT TUE JUN 18 2013

WYZ104-105-109>116-191100-
FERRIS/SEMINOE/SHIRLEY MOUNTAINS-SHIRLEY BASIN-
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-
1130 AM MDT TUE JUN 18 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED AFTERNOON AND EARLY EVENING THUNDERSTORMS WILL DEVELOP
OVER THE MOUNTAINS. GUSTY WINDS TO 50 MPH AND SMALL HAIL WILL BE
POSSIBLE WITH THE STRONGER STORMS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SOUTHWEST WINDS WILL GUST AS HIGH AS 40 MPH WEDNESDAY THROUGH
FRIDAY. THESE GUSTY WINDS WILL COMBINE WITH VERY LOW RELATIVE
HUMIDITIES AND WARM DAYTIME TEMPERATURES TO INCREASE THE FIRE
DANGER.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE REQUIRED TODAY AND TONIGHT.

&&

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-WYZ101>103-106>108-117>119-
191100-
DAWES-BOX BUTTE-SCOTTS BLUFF-BANNER-MORRILL-KIMBALL-CHEYENNE-
NORTH SIOUX-SOUTH SIOUX-CONVERSE COUNTY LOWER ELEVATIONS-
NIOBRARA COUNTY-NORTH LARAMIE RANGE-
CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE COUNTY-
EAST PLATTE COUNTY-GOSHEN COUNTY-SOUTH LARAMIE RANGE FOOTHILLS-
CENTRAL LARAMIE COUNTY-EAST LARAMIE COUNTY-
1130 AM MDT TUE JUN 18 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE WESTERN NEBRASKA
PANHANDLE...EAST CENTRAL WYOMING AND SOUTHEAST WYOMING.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS WILL DEVELOP EARLY THIS AFTERNOON ALONG THE
LARAMIE RANGE AND MOVE EAST ONTO THE PLAINS DURING THE AFTERNOON.
SOME OF THE STORMS EAST OF A LINE FROM DOUGLAS TO CHEYENNE WILL
BECOME SEVERE PRODUCING LARGE HAIL AND DAMAGING WINDS. THE
THUNDERSTORMS WILL MOVE INTO THE WESTERN NEBRASKA PANHANDLE THIS
EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

ISOLATED LATE DAY THUNDERSTORMS WILL BE POSSIBLE FRIDAY THROUGH
SUNDAY. SEVERE WEATHER IS NOT EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED FROM LATE THIS AFTERNOON
THROUGH EARLY THIS 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
321 PM MDT TUE JUN 18 2013

WYZ101-102-107-182200-
CONVERSE COUNTY LOWER ELEVATIONS WY-EAST PLATTE COUNTY WY-NIOBRARA
COUNTY WY-
321 PM MDT TUE JUN 18 2013

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN PLATTE...EASTERN
CONVERSE AND EXTREME SOUTHWESTERN NIOBRARA COUNTIES UNTIL 400 PM
MDT...

AT 320 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 11 MILES NORTHWEST OF GLENDO...OR 15 MILES
SOUTHEAST OF DOUGLAS...MOVING EAST AT 20 MPH.

WIND GUSTS UP TO 55 MPH ARE EXPECTED WITH THIS STORM.

THIS STORM WILL BE NEAR...
LOST SPRINGS AROUND 400 PM MDT.

THIS INCLUDES INTERSTATE 25 IN WYOMING BETWEEN MILE MARKERS 112 AND
131.

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

&&

LAT...LON 4292 10496 4246 10478 4253 10525 4269 10529
TIME...MOT...LOC 2121Z 253DEG 16KT 4264 10515

RUBIN

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHEYENNE WY
405 PM MDT TUE JUN 18 2013

WYZ101-103>106-109>116-190100-
CONVERSE COUNTY LOWER ELEVATIONS-NORTH LARAMIE RANGE-
FERRIS/SEMINOE/SHIRLEY MOUNTAINS-SHIRLEY BASIN-
CENTRAL LARAMIE RANGE AND SOUTHWEST PLATTE 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-
INCLUDING THE CITIES OF...DOUGLAS...GLENROCK...MUDDY GAP...
MEDICINE BOW...BORDEAUX...RAWLINS...SINCLAIR...HANNA...
ARLINGTON...ELK MOUNTAIN...BAGGS...DIXON...SARATOGA...
ENCAMPMENT...RIVERSIDE...CENTENNIAL...ALBANY...WOODS LANDING...
LARAMIE...VEDAUWOO...BUFORD...PUMPKIN VINE
405 PM MDT TUE JUN 18 2013

THROUGH EARLY THIS EVENING...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL MOVE NORTHEAST AT 20 MPH. SOME OF THE SHOWERS
AND THUNDERSTORMS WILL PRODUCE ISOLATED AND BRIEF WIND GUSTS UP TO
60 MPH.

AT 355 PM MDT...A WIND GUST OF 60 MPH OCCURRED FROM A SHOWER NEAR
SARATOGA IN SOUTH CENTRAL CARBON COUNTY.

RUBIN