Area Forecast Discussion
Issued by NWS Cheyenne, WY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KCYS 040602
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1202 AM MDT FRI SEP 4 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 246 PM MDT THU SEP 3 2015

CURRENT RADAR IMAGERY SHOWS SHOWERS AND THUNDERSTORMS MOVING INTO
SOUTHERN WYOMING AND NEBRASKA PANHANDLE. THESE SHOWERS WILL
CONTINUE TO MOVE NORTHWARD THROUGH THIS EVENING DUE TO A WEAK
SHORTWAVE MOVING THROUGH THE CWA. THUNDERSTORMS ARE NOT EXPECTED
TO BE SEVERE...WITH THE MAIN CONCERNS BEING LOCALLY HEAVY
RAINFALL FROM A FEW THUNDERSTORMS. TONIGHT CHANCE OF POPS WILL
START TO DECREASE WITH THE SHORTWAVE DISTURBANCE PUSHING OFF TO
THE NORTHEAST. ON FRIDAY THERE IS DIFFLUENCE ALOFT ASSOCIATED WITH
THE UPPER LEVEL JET. EXPECT TO SEE SOME SHOWERS AND THUNDERSTORMS
DEVELOPING INTO THE AFTERNOON AND EVENING HOURS...THE BEST CHANCES
WEST OF THE LARAMIE RANGE. SATURDAY THERE IS AN UPPER LEVEL
TROUGH...CURRENTLY OVER THE PACIFIC NORTHWEST...THAT WILL BEGIN
TO MOVE OVER THE CWA. A FEW SHOWERS AND THUNDERSTORMS WILL ONCE
AGAIN BE POSSIBLE BUT OVERALL POP CHANCES WILL BE ON THE LOW SIDE.
TEMPERATURES WILL BEGIN TO TREND COOLER AS THE TROUGH SHIFTS INTO
THE AREA.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 246 PM MDT THU SEP 3 2015

THE MEDIUM RANGE MODEL GUIDANCE PROGS THE UPPER TROUGH TO TRACK
NORTHEAST ACROSS MT AND NORTHERN WY SATURDAY NIGHT AND SUNDAY
MORNING WITH A PACIFIC FRONTAL PASSAGE. POST-FRONTAL SURFACE WINDS
WILL INCREASE SUNDAY MORNING WITH 700MB WINDS OF 35 TO 50 KT OVER
EAST CENTRAL AND SOUTHEAST WY. THE GRADIENT RELAXES SUNDAY AFTERNOON
WITH DIMINISHING WINDS. THE MUCH DRIER AIR MASS COMBINED WITH THE
GUSTY WINDS WILL RAISE THE FIRE DANGER DESPITE COOLER TEMPERATURES.
THE DRY ZONAL FLOW ALOFT WILL PREVAIL THROUGH EARLY NEXT WEEK WITH
PRECIPITABLE WATER VALUES OF 0.25-0.5 INCH. TEMPERATURES WILL AVERAGE
NEAR SEASONAL NORMALS. THERE ARE MODEL DIFFERENCES BY THE MIDDLE OF
NEXT WEEK AS THE GFS AND ECMWF DIFFER IN THE LOCATION AND STRENGTH
OF A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN ROCKIES AND
PLAINS. NONETHELESS...IT SHOULD BE A DRY PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1142 PM MDT THU SEP 3 2015

ISOLATED SHOWERS AND A BKN LAYER OF CLOUDS WITH BASES AROUND 10000
FT WILL CONTINUE TO AFFECT PORTIONS OF THE NEBRASKA PANHANDLE
FOR THE NEXT FEW HOURS. MOSTLY CLEAR SKIES WILL THEN OCCUR THROUGH
THE REMAINDER OF THE NIGHT. ISOLATED SHOWERS AND THUNDERSTORMS
WILL DEVELOP OVER AREAS TO THE WEST OF THE LARAMIE RANGE BY FRI
AFTN.

&&

.FIRE WEATHER...
ISSUED AT 246 PM MDT THU SEP 3 2015

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL BE COMMON THROUGH
SATURDAY...ESPECIALLY DURING THE AFTERNOON HOURS. WINDS WILL GENERALLY
BE ON THE LIGHTER SIDES ALONG WITH HIGHER DEW POINTS. THEREFORE NO
FIRE WEATHER CONCERNS THROUGH SATURDAY.

A STRONG DISTURBANCE WILL MOVE ACROSS THE NORTHERN ROCKIES SATURDAY
NIGHT. GUSTY WEST WINDS WILL DEVELOP BEHIND THIS DISTURBANCE
ON SUNDAY ALONG WITH MUCH DRIER AIR. WEST WINDS GUSTING 30 TO 40 MPH
WILL BE COMMON SUNDAY. CRITICAL TO NEAR CRITICAL FIRE WEATHER
CONDITIONS CAN BE EXPECTED WITH RELATIVE HUMIDITY VALUES DIPPING INTO
THE 10 TO 20 PERCENT RANGE.

&&

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

$$

SHORT TERM...SML/KC
LONG TERM...MAJ
AVIATION...ZF
FIRE WEATHER...SML


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.