Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 270427
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
927 PM MST MON JAN 26 2015

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 240 PM MST MON JAN 26 2015

THE BIG STORY THROUGH TUES AFTERNOON WILL BE THE ABNORMALLY WARM
TEMPS FOR LATE JANUARY. 700MB TEMPS AROUND 6C AND CLEAR SKIES ARE
RESULTING IN WIDESPREAD HIGHS IN THE MID TO UPPER 60S ACROSS THE
PLAINS. THIS IS A GOOD 25 DEGREES ABOVE NORMAL FOR THIS TIME OF
YEAR AND RECORD HIGHS ARE BEING SET AT A FEW LOCATIONS IN
SOUTHEAST WY. CHEYENNE HAS HIT 67 DEGREES SO FAR WHICH IS THE
WARMEST JANUARY DAY ON RECORD. STRONG RIDGE ALOFT WILL REMAIN IN
PLACE THROUGH TUESDAY. MOS GUIDANCE SHOWS HIGHS A FEW DEGREES
WARMER ON TUESDAY WHICH MEANS WE WILL BE GETTING CLOSE TO 70
DEGREES...ESPECIALLY OVER THE NEBRASKA PANHANDLE. THE RIDGE DOES
FLATTEN ON TUES NIGHT WITH A SHORTWAVE (CURRENTLY OVER SOUTHERN
CALIFORNIA) MOVING ACROSS THE CWA.

CONCERN ON TUESDAY NIGHT INTO WEDNESDAY MORNING WILL TURN TO THE
WINDS ACROSS SOUTHEAST WY AND ESPECIALLY THE WIND PRONE AREAS.  THE
LLVL CAG-CPR GRADIENT IS MARGINAL FOR HIGH WINDS WITH BOTH THE 850MB
AND 700MB GRADIENTS AROUND 45-50 METERS FROM 00Z-12Z WED.  850MB
WINDS ARE AROUND 35 KTS IN SOUTHERN PLATTE COUNTY SO DECIDED TO
UPGRADE THE BORDEAUX AREA TO A HIGH WIND WARNING.  WHILE THERE WILL
NO DOUBT BE AN INCREASE IN WINDS ON TUES NIGHT BEHIND THE
FRONT...WOULD LIKE TO SEE WINDS ALOFT A BIT STRONGER TO GET EXCITED
ABOUT HIGH WINDS IN THE OTHER WIND PRONE ZONES ESPECIALLY SINCE LLVL
MIXING WILL BE NOT AS GOOD AT NIGHT. WILL LEAVE THE HIGH WIND WATCH
IN EFFECT FOR THE SOUTHERN LARAMIE RANGE AND ARLINGTON
AREAS...HOWEVER NOT CONFIDENT AT THIS POINT THAT WIDESPREAD HIGH
WINDS WILL BE REACHED.  TEMPS WILL BE AROUND 15 DEGREES COOLER ON
WED IN THE POST FRONTAL AIRMASS.  SNOW WILL ALSO BECOME LIKELY OVER
THE SIERRA MADRE AND SNOWY RANGES FROM MIDDAY WED INTO WED NIGHT IN
MOIST NORTHWESTERLY FLOW BEHIND THE SHORTWAVE.  ACCUMULATIONS OF 3-5
INCHES WILL BE POSSIBLE WITH THE HIGHEST AMOUNTS ON WEST FACING
SLOPES.

.LONG TERM...(THURSDAY THROUGH NEXT MONDAY)
ISSUED AT 340 PM MST MON JAN 26 2015

LONG RANGE MODELS IN REASONABLE AGREEMENT SHOWING THE BREAK DOWN
OF THE UPPER LEVEL RIDGE THROUGH THURSDAY AS A SERIES OF PACIFIC
DISTURBANCES MOVE ONSHORE. COOLER TEMPERATURES AND THE POTENTIAL
FOR SOME SNOWFALL IS POSSIBLE FOR LATE FRIDAY AND SATURDAY AS
THIS ENERGY PUSHES EASTWARD OVER THE ROCKY MOUNTAINS. HIGH
TEMPERATURES WILL LOWER BACK DOWN TO NEAR NORMAL FOR THURSDAY AND
FRIDAY...WITH HIGHS IN THE 40S ACROSS MOST OF THE AREA.

ATTENTION THEN SHIFTS TOWARDS THE SOUTHWEST UNITED STATES ON
FRIDAY AS MODELS SHOW A BROAD UPPER LEVEL LOW OVER ARIZONA
DRIFTING EAST AND BECOMING AN OPEN WAVE TROUGH. THE NORTHERN
BRANCH OF THE JET STREAM WILL DIG SOUTHWARD INTO THE NORTHERN
PLAINS AS WELL RESULTING IN COLDER TEMPERATURES FOR THIS WEEKEND
WITH HIGHS IN THE 20S TO MID 30S. AS A SURFACE HIGH MOVES OVER THE
NORTHERN PLAINS AND INTO THE GREAT LAKES REGION...SOME UPSLOPE
FLOW WILL DEVELOP ACROSS THE HIGH PLAINS. BUT WITH THE LACK OF ANY
REAL DEFINED LOW TO MIDLEVEL DYNAMIC FORCING...BELIEVE ANY
SNOWFALL WILL BE RATHER LIGHT WITH LIGHT SNOW ACCUMULATIONS AT
BEST. MOST OF THE DYNAMIC FORCING WILL BE WELL TO THE SOUTH OF THE
FORECAST AREA SO IMPACTS SHOULD BE LOW TO MODERATE ACROSS
SOUTHEAST WYOMING...AND MAYBE WESTERN NEBRASKA. THE BEST CHANCE OF
ACCUMULATING SNOW WILL BE FRIDAY NIGHT THROUGH LATE SATURDAY
MORNING. INCREASED POP BETWEEN 20 TO 30 PERCENT FOR NOW ACROSS
MOST OF THE FORECAST AREA.

WEST TO NORTHWEST FLOW WILL RETURN TO THE AREA BY MONDAY WITH
WARM DOWNSLOPE WINDS AND THE POTENTIAL FOR VERY WINDY
CONDITIONS...ESPECIALLY ACROSS SOUTHEAST WYOMING. TEMPERATURES
WILL RESPOND BY SUNDAY AND ESPECIALLY NEXT MONDAY...WITH HIGHS
NEAR 50 ONCE AGAIN ACROSS THE HIGH PLAINS. NO MAJOR STORM SYSTEMS
ARE EXPECTED THROUGH THE MIDDLE OF NEXT WEEK AS THE PACIFIC HIGH
ATTEMPTS TO REBUILD ACROSS THE SOUTHWEST UNITED STATES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 926 PM MST MON JAN 26 2015

VFR CONDITIONS WILL PREVAIL AT AREA TERMINALS WITH INCREASING
FEW-SCT250 CLOUD DECK AFTER NOON. WEST WINDS WILL BECOME BREEZY AT
SE WY SITES AFTER AROUND 18Z TUESDAY...WHICH LIKELY WILL CONTINUE
AND/OR STRENGTHEN AS THE FRONT APPROACHES AND EVENTUALLY PUSHES
THRU AFTER 28/00Z.

&&

.FIRE WEATHER...

THE ABNORMALLY WARM AND DRY CONDITIONS WILL CONTINUE THROUGH
TUESDAY.  TEMPERATURES WILL BE 25-30 DEGREES ABOVE NORMAL WITH
WIDESPREAD HIGHS IN THE 60S TO THE EAST OF THE LARAMIE RANGE.
MINIMUM RELATIVE HUMIDITY VALUES WILL FALL INTO THE 15-25 PERCENT
RANGE ON TUESDAY AFTERNOON ACROSS THE PLAINS.  WEST WINDS WILL ALSO
BE BREEZY ACROSS SOUTHEAST WY DURING THE AFTERNOON...SO AN ELEVATED
FIRE WEATHER RISK IS WARRANTED.  COOLER TEMPERATURES AND HIGHER
HUMIDITY VALUES WILL ARRIVE ON WEDNESDAY BEHIND A COLD FRONT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING
     FOR WYZ110-116-117.

     HIGH WIND WARNING FROM 2 PM TUESDAY TO 8 AM MST WEDNESDAY FOR
     WYZ106.

NE...NONE.
&&

$$

SHORT TERM...ZF
LONG TERM...TJT
AVIATION...CAH
FIRE WEATHER...ZF


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