Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 212355
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
455 PM MST WED JAN 21 2015

.SHORT TERM...(LATE THIS AFTERNOON THROUGH FRIDAY NIGHT)
ISSUED AT 255 PM MST WED JAN 21 2015

AFTERNOON GOES WATER VAPOR ANIMATION SHOWED A POSITIVELY-TILTED
UPPER TROUGH FROM THE UPPER MIDWEST TO THE FOUR CORNERS REGION.
POTENT SHORTWAVE WAS TRACKING EAST FROM AZ TOWARD NM WITH A WEAKER
WAVE MOVING SOUTH ACROSS WESTERN CO. REGIONAL RADARS INDICATED
LIGHT SNOW SHOWERS OVER SOUTHERN LARAMIE...SNOWY AND SIERRA MADRE
RANGES. THIS ACTIVITY WILL WILL CONTINUE THROUGH LATE AFTERNOON
BEFORE ENDING AS DRIER ALOFT SPREADS SOUTH BEHIND THE EXITING
SHORTWAVE. SKIES WERE PARTLY TO MOSTLY CLOUDY WITH TEMPERATURES
FROM THE LOW 20S TO MID 30S. NORTHERLY WINDS AVERAGED 10-15 KT
WITH GUSTS TO 25 KT.

UPPER RIDGE AXIS ALONG THE WEST COAST WILL BROADEN AND GRADUALLY
EXPAND EAST INTO THE INTERMOUNTAIN WEST DURING THE NEXT 24 TO 48
HOURS. THE ONLY POTENTIAL FLY IN THE OINTMENT WILL BE A WEAK
SHORTWAVE RIDING SOUTHEAST IN THE NORTHWEST FLOW ALOFT ACROSS THE
NORTHERN HIGH PLAINS LATE FRIDAY. BESIDES AN INCREASE IN MID/HIGH
CLOUDINESS...LIGHT PRECIPITATION WILL BE CONFINED TO THE NORTH AND
NORTHEAST OF THE CWFA. WEST TO NORTHWEST SURFACE WINDS WILL BE
BREEZY...MAINLY DURING THE DAYLIGHT HOURS THURSDAY. MODELS
INDICATE A UPTICK IN THE WINDS...ESPECIALLY ACROSS THE PLAINS
FRIDAY WITH 750-850MB WINDS APPROACHING 40 KT. IF MODELS MAINTAIN
THIS TREND...A WIND ADVISORY HIGHLIGHT MAY BE REQUIRED FOR THE
WESTERN NE PANHANDLE.

TONIGHT WILL EXPERIENCE THE COLDEST TEMPERATURES OF THE PERIOD AS
700MB TEMPERATURES HOVER AROUND -14C. EXPECT LOWS FROM -5 TO 15
DEGREES. TEMPERATURES BEGIN TO MODERATE THURSDAY WITH WESTERLY
DOWNSLOPE FLOW AND 700MB TEMPERATURES RISE TO -5C. EXPECT HIGHS IN
THE 30S PLAINS WITH 20S ALONG AND WEST OF THE LARAMIE RANGE.
MILDER THURSDAY NIGHT WITH LOWS IN THE TEENS AND 20S. ADD ANOTHER
5 TO 10 DEGREES FOR HIGH TEMPERATURES FRIDAY WITH 700MB TEMPERATURES
BETWEEN 0 AND -5C. LOWS FRIDAY NIGHT WILL BE SIMILAR TO THURSDAY
NIGHT.

.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 255 PM MST WED JAN 21 2015

QUITE MILD PATTERN WILL BE SETTING UP IN THE EXTENDED PERIOD...
ESPECIALLY BY EARLY NEXT WEEK. NORTHWESTERLY FLOW ALOFT WILL BE
IN PLACE ON SAT AND SUN WITH A STRONG UPPER LEVEL JET STRETCHING
FROM EASTERN MONTANA INTO THE NORTHERN PLAINS. THE CAG-CPR GRADIENT
WILL BE 40-55 METERS OVER THE WEEKEND (STRONGEST ON SUNDAY) SO IT
WILL DEFINITELY BE WINDY ACROSS SOUTHEAST WY. NOT SURE WE WILL SEE
WIDESPREAD HIGH WINDS IN THE WIND PRONE AREAS...ALTHOUGH PLACES
LIKE BORDEAUX AND THE SOUTHERN LARAMIE RANGE FOOTHILLS COULD GET
CLOSE. TEMPS WILL BE ABOVE NORMAL ON SUNDAY AS THE 700MB TEMPS
RISE TO 0-2C. UPPER LEVEL RIDGE MOVES OVERHEAD BY MON FOR CONTINUED
WARMING AND A WEAKER WINDS. THE 700MB TEMPS INCREASE FURTHER TO
AROUND 4C AND THE MEX GUIDANCE AT CHEYENNE IS 61 DEGREES. CURRENTLY
HAVE UPPER 50S FOR AREAS TO THE EAST OF THE LARAMIE RANGE BUT SOME
LOCATIONS COULD REACH 60 WITH WIDESPREAD SUNSHINE. NOT MUCH CHANGE
IN THE OVERALL PATTERN FOR TUE...ALTHOUGH THE GFS WOULD SUGGEST
SLIGHTLY COOLER TEMPS AS THE RIDGE BEGINS TO BREAK DOWN OVER THE
INTERMOUNTAIN WEST.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 453 PM MST WED JAN 21 2015

VFR. PERIODS OF MVFR CEILINGS AT CHADRON THROUGH 06Z.

&&

.FIRE WEATHER...
ISSUED AT 211 PM MST WED JAN 21 2015

MINIMAL FIRE WEATHER CONCERNS ARE ANTICIPATED THROUGH THE END OF
THE WEEK FOR THE DISTRICT. FEW SNOW SHOWERS OVER SOUTHEAST WYOMING
NEAR THE COLORADO BORDER WILL END BY THIS EVENING. OTHERWISE...DRY
CONDITIONS WILL PREVAIL THROUGH FRIDAY WITH MINIMUM RELATIVE
HUMIDITIES BETWEEN 20 AND 30 PERCENT OVER MUCH OF SOUTHEAST
WYOMING. IT WILL BE BREEZY WITH WESTERLY WINDS BETWEEN 15 AND 25
MPH.

&&

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

$$

SHORT TERM...MJ
LONG TERM...ZF
AVIATION...RUBIN
FIRE WEATHER...MJ


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