Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 011643
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1043 AM MDT MON JUN 1 2015

.UPDATE...
ISSUED AT 1041 AM MDT MON JUN 1 2015

FOG IN THE NORTH PLATTE RIVER VALLEY DISSIPATED IN SHORT ORDER
THIS MORNING WITH A LITTLE HELP FROM THE HIGH JUNE SUN ANGLE. LOW
LEVEL MOISTURE AND THAT SAME JUNE SUN WILL AID IN THE DEVELOPMENT
OF THUNDERSTORMS THIS AFTERNOON. WILL APPROACH CONVECTIVE
TEMPERATURE OVER THE MOUNTAINS MOMENTARILY. ALREADY SEEING
CONVECTION FORMING OVER THE COLORADO MOUNTAINS. ALSO AN AREA OF
SHOWERS IS CURRENTLY MOVING ACROSS CARBON COUNTY.

MODELS CONTINUE TO SHOW MU CAPES FROM AROUND 500 J/KG THIS
AFTERNOON OVER MOST OF WYOMING AND THEN 1000-2000 J/KG INTO THE
NEBRASKA PANHANDLE. 0-6 KM BULK SHEAR VALUES NOT THE MOST
IMPRESSIVE AROUND 30 KTS BUT THAT IS ENOUGH FOR AT LEAST MARGINAL
SEVERE STORMS. HIGHER THREAT FOR SEVERE STORMS IS INTO THE
NEBRAKSA PANHANDLE WHERE THERE IS A GREATER POTENTIAL FOR
VIGOROUS THUNDERSTORM UPDRAFTS. LARGER HAIL IS THE MAIN SEVERE
WEATHER CONCERN BUT GUSTY WINDS ARE POSSIBLE. ALSO THE TORNADO
THREAT IS LOW BUT NOT ZERO. MAIN CHANCES FOR TORNADIC ACTIVITY
WILL BE IN THE PANHANDLE..PARTICULARLY NEAR THE EASTERN CWA
EDGES.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 352 AM MDT MON JUN 1 2015

RATHER TYPICAL LATE SPRING WEATHER EXPECTED ACROSS THE CWA TODAY
THROUGH WEDS WITH WARM TEMPS AND AT LEAST WDLY SCTD MAINLY
AFTERNOON AND EVENING CONVECTION. TEMPS WILL BE WARM TODAY AND
TUESDAY AS 700MB TEMPS RISE TO AROUND 12-13C WITH MANY AREAS OVER
THE PLAINS SURPASSING 80F TODAY AND AGAIN TUESDAY. CONVECTION
SHOULD INITIATE AROUND THE MTNS EARLY THIS AFTERNOON THEN PROGRESS
EAST THROUGH THIS EVENING. DECENT CAPES PROGGED TODAY PARTICULARLY
OVER THE PANHANDLE WITH VALUES OVER 2000 J/KG. BETTER SHEAR WITH
STRONGER WESTERLIES WILL BE TO THE NORTH BUT A FEW STRONGER STORMS
POSSIBLE THIS AFTERNOON. CLEARING LATER THIS EVENING WITH UPPER
RIDGE AXIS PASSING ACROSS THE REGION. TUESDAY LOOKING A LITTLE
DRIER AS CONVECTION SHOULD BE SUPPRESSED BY SOME MID LEVEL
SUBSIDENCE BEHIND A DEPARTING SHORTWAVE BUT A SFC TROF PROGRESSING
OVER THE PANHANDLE SHOULD SERVE TO FOCUS SOME CONVECTION IN THAT
AREA.

A COOL FRONT WILL THEN SETTLE SOUTH ACROSS THE CWA TUESDAY NIGHT
AND BRING ABOUT 5-10 DEGREES OF COOLING FOR MAXS WEDS. SFC UPSLOPE
FLOW BEHIND THIS FRONT WILL SET UP A BETTER SHEAR PATTERN WITH
CAPES IN EXCESS OF 2500 J/KG FROM FAR SE WY INTO THE SOUTHERN
PANHANDLE SO STRONGER/SEVERE STORMS A BETTER BET WEDS AFTERNOON.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 352 AM MDT MON JUN 1 2015

THE ACTIVE PATTERN LOOKS TO CONTINUE THROUGH THE WEEKEND AS AN
UPPER LOW DIGS SOUTH ALONG THE CALIFORNIA COAST AND AMPLIFIES
THE DOWNSTREAM RIDGE OVER THE ROCKIES. A NUMBER OF SHORTWAVE
FEATURES WILL MOVE OVER THE FORECAST AREA IN THIS PATTERN...AND
COMBINED WITH ESE SFC UPSLOPE FLOW AND LLVL MOISTURE EAST OF A
PERSISTENT INVERTED SFC TROUGH ALONG THE LARAMIE RANGE...WILL KEEP
GOOD CHANCES FOR SHOWERS AND SCATTERED THUNDERSTORMS THROUGH THIS
TIME. ON THURSDAY...1000-2000 J/KG OF SBCAPES ARE FORECAST ACROSS
THE PLAINS AND ALONG WITH BULK SHEAR OF 35 KTS OR GREATER
OVERHEAD...SHOULD SEE A FEW STORMS BECOME STRONGER/SEVERE MAINLY
ACROSS THE EASTERN PLAINS. SHOWERS SHOULD CONTINUE OVERNIGHT AS
THE UPPER JET SHIFTS OVER THE FORECAST AREA. FRIDAY WILL SEE
STRONGER MIDLEVEL ENERGY MOVE UP FROM THE SOUTHWEST ALONG WITH
PERSISTENT SSE UPSLOPE WINDS. MORE OVERALL CLOUD COVER WITH THE
MIDLEVEL ENERGY MAY KEEP TEMPS DOWN A FEW DEGREES THUS INSTABILITY
MAY NOT BE AS HIGH. THERE STILL COULD BE A FEW STRONG/SEVERE
STORMS ACROSS THE PLAINS THOUGH WITH STRONGEST WINDS ALOFT
INCREASING OVERALL SHEAR...SO WILL KEEP A CLOSE EYE AS THE
FORECAST EVOLVES THE NEXT FEW DAYS. THE SFC TROUGH LOOKS TO SHIFT
EAST ON SATURDAY WITH THE FOCUS FOR STRONGEST CONVECTION SOUTH AND
EAST OF THE FORECAST AREA. A COLD FRONT WILL START TO MOVE SOUTH
ACROSS THE FORECAST AREA AROUND SUNSET SATURDAY...WITH SHOWERS AND
AT LEAST ISOLATED TSTORMS EXPECTED TO CONTINUE OVERNIGHT AS THE
FRONT MOVES THROUGH. ESE UPSLOPE FLOW RETURNS FOR SUNDAY...SO
EXPECT A DECENT CHANCE FOR SHOWERS AND T-STORMS ESPECIALLY IN THE
EVENING VCTY THE LARAMIE RANGE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 542 AM MDT MON JUN 1 2015

FOG/LOW STRATUS HAS SETTLED INTO PORTIONS OF THE NEBRASKA
PANHANDLE BELOW 4000 FEET EARLY THIS MORNING...AND SHOULD LINGER
THROUGH ROUGHLY 14Z BEFORE DISSIPATING. OTHERWISE...LOOKING AT
SOME MID AND HIGH CLOUDS MOVING ACROSS THE AREA THROUGH EARLY
AFTERNOON WITH ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
DEVELOPING THROUGH THE AFTERNOON AND EVENING. MVFR CONDITIONS ARE
POSSIBLE IN THE HEAVIER STORMS MAINLY ALONG AND EAST OF THE
LARAMIE RANGE. THIS ACTIVITY WILL DIMINISH WITH SUNSET...AND
CONDITIONS LOOK FAVORABLE FOR A RETURN OF FOG/LOW STRATUS TO THE
EASTERN NEB SITES ONCE AGAIN EARLY TUESDAY MORNING.


&&

.FIRE WEATHER...
ISSUED AT 352 AM MDT MON JUN 1 2015

WARM TEMPERATURES WILL BE OVER THE DISTRICTS TODAY AND TUESDAY
BEFORE A LITTLE COOLER AIR ARRIVES ON WEDNESDAY. NEARLY DAILY
CHANCES FOR SCTD SHOWERS AND TSTRMS MUCH OF THIS WEEK. CONCERNS
WILL REMAIN QUITE LOW WITH NO CRITICAL CONDITIONS SEEN.

&&

.HYDROLOGY...
ISSUED AT 352 AM MDT MON JUN 1 2015

RUNOFF FROM MTN SNOWMELT EXPECTED TO RAISE THE UPPER NORTH PLATTE
RIVER TO THROUGH THE WEEK BUT REMAIN BELOW FLOOD STAGE. THE
LARAMIE RIVER IS EXPECTED TO SURPASS FLOOD STAGE AT LARAMIE WEDS
MORNING WHILE FALLING BELOW FLOOD STAGE AT FT LARAMIE LATE THIS
WEEK. THE N PLATTE IN THE WESTERN NEB PANHANDLE IS PRETTY MUCH
CRESTING AND WILL FALL THIS WEEK AND BE ENTIRELY BELOW FLOOD
STAGE BY WEDS MORNING. THERE WILL BE SCTD SHOWERS AND TSTMS MUCH
OF THIS WEEK BUT RUNOFF DOES NOT APPEAR IT WILL HAVE A SIG EFFECT
ON RIVERS AT THIS TIME.

&&

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

&&

$$

UPDATE...SML
SHORT TERM...RE
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...RE
HYDROLOGY...RE



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