Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 272135
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
235 PM MST TUE JAN 27 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 205 PM MST TUE JAN 27 2015

ANOTHER WARM DAY ACROSS THE REGION WITH WIDESPREAD HIGHS IN THE
UPPER 60S TO LOW 70S ACROSS THE PLAINS...WHICH IS A FEW DEGREES
WARMER THAN YESTERDAY. CHEYENNE HAS SET YET ANOTHER JANUARY RECORD
HIGH TEMPERATURES BY GETTING TO 70 DEGREES. HIGH CLOUDS HAVE BEGUN
TO INCREASE ALONG AND WEST OF THE LARAMIE RANGE BUT THEY HAVE NOT
BEEN THICK ENOUGH TO KEEP TEMPS FROM RISING. WATER VAPOR IMAGERY
SHOWS AN UPPER LEVEL SHORTWAVE ACROSS CENTRAL NEVADA. THIS
FEATURE IS PROGGED TO MOVE OVER THE CWA TONIGHT...WITH A COLD
FRONT PUSHING ACROSS. LLVL GRADIENTS ARE ON THE INCREASE THIS
AFTERNOON AND WILL RISE FURTHER THROUGH EARLY TONIGHT. THE 850MB
CAG-CPR GRADIENT (CURRENTLY AROUND 40 METERS) WILL PEAK AT 55
METERS BY 09Z WED. THIS A BIT STRONGER THAN THE MODELS WERE
SHOWING YESTERDAY. STILL BELIEVE THAT THE STRONGEST PREFRONTAL WINDS
WILL DEVELOP BY 03-06Z AT BORDEAUX AND ARLINGTON...THEN THE WINDS
WILL PICK UP ALONG INTERSTATE 80 BETWEEN CHEYENNE AND LARAMIE
BEHIND THE FRONT (AROUND 09Z). MOS GUIDANCE SHOWS WINDS INCREASING
TO 25-30 KTS AT CHEYENNE BEHIND THE FRONT...SO A BIT MORE
CONFIDENT THAT AT LEAST A FEW LOCATIONS IN THE SOUTHERN LARAMIE
RANGE AND ADJACENT FOOTHILLS WILL GET GUSTS CLOSE TO 50 KTS
CONSIDERING THE COLD AIR ADVECTION AND SUBSIDENCE. HIGH WIND
WARNINGS APPEAR TO BE WARRANTED...ALTHOUGH THIS EVENT IS STILL
EXPECTED TO BE RATHER MARGINAL.

IT WILL BE A BREEZY TO WINDY DAY ACROSS THE PLAINS ON WEDNESDAY
AND TEMPERATURES WILL BE 20-25 DEGREES COOLER. WINDS ACROSS THE
NEBRASKA PANHANDLE WILL BE HIGHEST ALONG INTERSTATE 80 STRETCHING
FROM KIMBALL TO SIDNEY. THIS IS WHERE GUSTS TO 35-40 KTS WILL BE
POSSIBLE DURING THE MORNING THROUGH THE EARLY AFTN. THINKING IS
THAT WINDS WILL FALL JUST SHORT OF WIND ADVISORY...HOWEVER IT IS
SOMETHING THAT THE OVERNIGHT SHIFT WILL HAVE TO MONITOR. WITH
REGARD TO PRECIPITATION BEHIND THE FRONT...THE MODELS HAVE BEEN
CONSISTENT AT SHOWING 3-6 INCHES ACROSS THE SIERRA MADRE AND SNOWY
RANGES STARTING LATE TONIGHT AND PERSISTING TROUGH WEDNESDAY
EVENING. THE BEST CHANCE OF PRECIP OVER LOWER ELEVATIONS IS OVER
NORTHERN ZONES ALTHOUGH QPF AMOUNTS ARE STILL LESS THAN A TENTH OF
AN INCH. EXPECT ANOTHER FEW DEGREES OF COOLING ON THURSDAY WITH
PRESSURE GRADIENTS AND WINDS MUCH WEAKER THAN WEDNESDAY.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 205 PM MST TUE JAN 27 2015

THE EXTENDED PERIOD BEGINS WITH A POTENT MID LEVEL SHORTWAVE ACROSS
THE SOUTHWEST CONUS ON FRI. TEMPERATURES ARE EXPECTED TO BE AROUND
SEASONAL NORMS FOR FRIDAY...BUT AN INCREASE IN MID AND HIGH LEVEL
CLOUDS ALONG WITH A SURFACE COLD FROPA WILL TEND TO COMPLICATE
THINGS. CONSENSUS MOS STILL SUGGESTS MID 40S FOR HIGHS...ALTHOUGH H7
TEMPS AROUND -5 DEG C PER THE GFS/ECMWF MAKE THAT A LITTLE DIFFICULT
TO BELIEVE. H7-H3 MOISTURE PROGS RAMP UP ON SAT/SUN ALONG WITH MOIST
OROGRAPHICS OVER THE SNOWIES AND SIERRA MADRES. SHOULD SEE SOME SNOW
ACCUMULATIONS OVER THE WEEKEND...BUT MEDIUM RANGE MODELS ARE IN GOOD
AGREEMENT WITH THE UPPER LOW SITUATED WELL TO THE SOUTH ALONG THE US
AND MEXICO BORDER. OUR MOUNTAINS WOULD BE ON THE NORTHERN FRINGE OF
THE BEST AIR MASS AT BEST...SO AT THIS TIME IT IS LOOKING LIKE A SUB
ADVISORY EVENT. MAIN COLD FRONT LOOKS TO ARRIVE SAT NIGHT OR SUN AS
H7 TEMPS PLUNGE TO AROUND -10 DEG OVER THE WY/NE STATE LINE. A FEW
PIECES OF MID LEVEL ENERGY EMANATING FROM A HUDSON BAY LOW MAY KEEP
AT LEAST ISOLATED PCPN CHANCES GOING THROUGH EARLY NEXT WEEK. WHILE
IT WILL BE VERY DIFFERENT THAN OUR RECENT STRETCH OF RECORD BREAKING
WARMTH...NO MAJOR STORMS APPEAR TO BE IN THE OFFING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1031 AM MST TUE JAN 27 2015

VFR CONDITIONS WILL OCCUR TODAY WITH SCATTERED CIRRUS SPREADING
FROM WEST TO EAST ACROSS THE AREA. WINDY CONDITIONS ARE EXPECTED
TO CONTINUE OVER THE SOUTHEAST WYOMING TERMINALS THROUGH MUCH OF
THE TAF PERIOD. CEILINGS WILL LOWER TO AROUND 5K FEET AGL OVER A
LARGE PART OF THE AREA EARLY ON WED MORNING. MVFR TO IFR CIGS ARE
FORECAST AT KRWL AFTER 09Z WED WITH INCREASING CHANCES FOR RAIN OR
SNOW SHOWERS.

&&

.FIRE WEATHER...
ISSUED AT 205 PM MST TUE JAN 27 2015

WITH A COLD FRONT MOVING ACROSS THE AREA TONIGHT...MUCH COOLER
TEMPERATURES ARE EXPECTED ON WEDNESDAY. THIS WILL CAUSE AFTERNOON
HUMIDITY VALUES TO INCREASE TO AROUND 40 PERCENT. WINDY CONDITIONS
WILL DEVELOP BY LATE TONIGHT AND PERSIST THROUGH WEDNESDAY
AFTERNOON. ALTHOUGH WIDESPREAD SNOW ACCUMULATIONS OF 3-6 INCHES
WILL BE POSSIBLE IN THE SIERRA MADRE AND SNOWY RANGES FROM LATE
TONIGHT THROUGH WEDNESDAY...MUCH OF THE LOWER ELEVATIONS WILL
REMAIN PRECIPITATION FREE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 11 AM MST WEDNESDAY FOR WYZ110-116-117.

     HIGH WIND WARNING UNTIL 8 AM MST WEDNESDAY FOR WYZ106.

NE...NONE.
&&

$$

SHORT TERM...ZF
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...ZF


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