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 131824
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1124 AM MST SAT FEB 13 2016

.UPDATE...
ISSUED AT 1119 AM MST SAT FEB 13 2016

FOG HAS FINALLY LIFTED ACROSS THE NEBRASKA PANHANDLE. NOW THE MAIN
WEATHER CONCERN SHIFTS TO STRONG WINDS ACROSS THE WIND PRONE
PORTIONS OF SOUTHEAST WYOMING. AT THIS TIME THE WINDS ARE BELOW
HIGH WIND THRESHOLDS BUT AS A FAST MOVING SHORTWAVE MOVES ACROSS
NORTHEAST WYOMING THIS AFTERNOON WINDS SHOULD ACCELERATE. COULD
SEE A BRIEF PERIOD OF HIGH WINDS SPREAD EAST INTO THE INTERSTATE
25 CORRIDOR EARLY THIS EVENING INCLUDING THE CITY OF CHEYENNE.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 345 AM MST SAT FEB 13 2016

CURRENT 11-3.9 FOG PRODUCT IMAGE SHOWS LOW CLOUDS AND FOG ACROSS
MOST OF THE NEBRASKA PANHANDLE AND EXTENDING EAST ACROSS CENTRAL
NEBRASKA AND NE COLORADO. SOME FOG HAS MADE IT AS FAR WEST AS
DOUGLAS AND PINE BLUFFS...AND BRIEFLY OVER CHEYENNE EARLIER THIS
MORNING. VISIBILITIES HAVE NOT BEEN TOO BAD
OVERNIGHT...PERIODICALLY LOWERING TO BETWEEN ONE HALF TO ONE MILE
AT TIMES NEAR THE WYOMING/NEBRASKA BORDER. WILL KEEP THE DENSE FOG
ADVISORY OUT FOR NOW...BUT WILL LIKELY EXPIRE IT ON TIME IN THE
NEXT HOUR. WINDS WILL GRADUALLY SHIFT INTO THE WEST...ALLOWING
BETTER MIXING AND SOME DRIER AIR TO SPREAD ACROSS WESTERN
NEBRASKA. HAVE RECEIVED A FEW REPORTS OF FREEZING DRIZZLE ACROSS
THE PANHANDLE OF NEBRASKA...BUT IMPACTS HAVE BEEN MINIMAL.

CURRENT WATER VAPOR LOOPS SHOWS AN UPPER LEVEL TROUGH RAPIDLY
MOVING SOUTHEAST INTO IDAHO EARLY THIS MORNING. THIS TROUGH WILL
QUICKLY MOVE ACROSS WYOMING TODAY...RESULTING IN INCREASING WINDS
OVER THE AREA. WINDS HAVE ALREADY STARTED TO INCREASE ACROSS THE
ARLINGTON AREA BETWEEN RAWLINS AND LARAMIE AND THE I80 SUMMIT...WITH
GUSTS AROUND 40 MPH OBSERVED. EXPECT THIS TREND TO CONTINUE TODAY
WITH WINDS APPROACHING HIGH WIND CRITERIA (SUSTAINED 40 MPH/GUSTS
OVER 58 MPH) BY THIS AFTERNOON. THIS EVENT APPEARS TO BE A
HYBRID OF A BORA AND GAP WIND SCENARIO...WITH WINDY CONDITIONS
AS FAR EAST AS THE NEBRASKA BORDER BY THIS EVENING. UPGRADED THE
HIGH WIND WATCH TO A WARNING OVER THE ARLINGTON AND BORDEAUX
AREAS. ADDED THE I80 SUMMIT AND FOOTHILLS TO THE WARNING AS WELL
DUE TO IMPRESSIVE LLVL SUBSIDENCE...AN INCREASING SURFACE
PRESSURE GRADIENT BETWEEN 18Z TODAY THROUGH 09Z TONIGHT...AND
700MB WINDS OVER 60 KNOTS. WITH THE EXCEPTION OF SW PLATTE
COUNTY...EXTENDED THE DURATION OF THE WARNING UNTIL 16Z SINCE
700MB WINDS REMAIN OVER 50 KNOTS THROUGH 15Z. WOULD NOT BE
SURPRISED TO SEE WINDS NEAR ARLINGTON CONTINUE TO GUST OVER 55 MPH
THROUGH SUNDAY AFTERNOON GIVEN CURRENT MODEL GRADIENTS ACROSS THE
AREA. IN ADDITION...THE HIGH WIND WARNING MAY NEED TO BE EXTENDED
EASTWARD TO INCLUDE CHEYENNE AND EASTERN PLATTE COUNTY BETWEEN
LATE THIS AFTERNOON UNTIL MIDNIGHT FOR A BRIEF PERIOD OF GUSTS
OVER 58 MPH. MODELS INDICATE THE STRONG LLVL SUBSIDENCE ASSOCIATED
WITH DOWNSLOPE WINDS EXTENDING EASTWARD OVER MOST OF THE I25
CORRIDOR BETWEEN 00Z TO 06Z THIS EVENING. INCREASED WINDS OVER
THESE AREAS A BIT...BUT WITH MODELS NOT IN AGREEMENT WITH THE AREA
OF SUBSIDENCE...KEPT THE EASTERN ZONES OUT OF THE WARNING FOR
NOW. OTHERWISE...HIGH TEMPERATURES WILL BE MILD AND GENERALLY IN
THE 40S TO MID 50S.

EXPECT WINDS TO BE ELEVATED ACROSS SOUTHEAST WYOMING ON SUNDAY
WITH SLIGHTLY COOLER TEMPERATURES. HIGHS ON SUNDAY WILL BE 10
DEGREES COOLER COMPARED TO TODAY...BUT STILL PLEASANT FOR THIS
TIME OF THE YEAR. MODELS INDICATE SOME SNOW SHOWER
ACTIVITY...MIXED WITH RAIN AT TIMES...MOVING OVER SOUTHEAST
WYOMING AS A SECONDARY DISTURBANCE MOVES SOUTHWARD EMBEDDED IN
NORTHWEST FLOW ALOFT. KEPT POP BETWEEN 15 TO 25 PERCENT FOR THE
LOWER ELEVATIONS WITH VALUES AROUND 80 PERCENT FOR THE MOUNTAINS.
MAY NEED A WINTER WEATHER ADVISORY FOR THE MOUNTAINS THROUGH
SUNDAY NIGHT FOR 6 TO 12 INCHES OF SNOW. MODELS SHOW ANOTHER
DISTURBANCE MOVING ACROSS MONTANA AND WYOMING ON MONDAY...BUT
PRODUCING LIGHT RAIN ACROSS THE EAST CENTRAL PLAINS INTO THE
NORTHERN PANHANDLE INSTEAD OF SNOW. HIGH WIND WATCHES WILL LIKELY
BE NEEDED OVER THE NEXT 24 TO 48 HOURS FOR PORTIONS OF SOUTHEAST
WYOMING FOR MONDAY AS WELL AS WINDS INCREASE AHEAD OF THE NEXT
DISTURBANCE.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 215 AM MST SAT FEB 13 2016

MONDAY NIGHT...AS THE FAST MOVING SHORTWAVE TROUGH ALOFT MOVES AWAY
FROM OUR REGION...LIFT AND MOISTURE WILL DECREASE...THUS POPS SHOULD
ALSO DECREASE OVERNIGHT INCLUDING ALONG THE SNOWY AND SIERRA MADRE
RANGES.

TUESDAY...FAST NORTHWEST FLOW ALOFT WILL PROMOTE A WINDY
DAY...ESPECIALLY FOR OUR WIND PRONE LOCATIONS SUCH AS
ARLINGTON...BORDEAUX AND VEDAUWOO OVER THE INTERSTATE 80 SUMMIT.
WITH LIMITED CLOUD COVER...HIGH TEMPERATURES WILL BE IN THE MID 40S
OVER THE LOWER ELEVATIONS OF ALBANY AND CARBON COUNTIES...WITH 50S
OVER THE EASTERN PLAINS TO THE EAST OF INTERSTATE 25.

TUESDAY NIGHT...COMBINATION OF A WARMING AIRMASS AND BREEZY
CONDITIONS WILL PRODUCE A RELATIVELY MILD OVERNIGHT...ESPECIALLY
ALONG AND JUST EAST OF THE LARAMIE RANGE.

WEDNESDAY...WILL BE ONE OF THE MILDEST DATES OF THE LATE WINTER WITH
PROGGED THICKNESSES NEAR 5610 METERS...PLENTY OF SUNSHINE AND A
MINIMUM OF CLOUDS.

THURSDAY...NEXT FAST MOVING SHORTWAVE TROUGH ALOFT MOVES OVER
WYOMING SPREADING INCREASING CLOUD COVER AND A CHANCE FOR SHOWERS.
FOR NOW WILL ONLY INTRODUCE THE SHOWERS OVER OUR WESTERN CARBON
COUNTY...WHICH MESHES WELL WITH OUR SURROUNDING FORECASTS.

.FRIDAY...ANOTHER RELATIVELY MILD DAY...THOUGH NOT AS WARM AS
THURSDAY BASED ON HEIGHT AND THICKNESS TRENDS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1059 AM MST SAT FEB 13 2016

LOW CLOUDS AND IFR CIGS WILL PERSIST AT SNY AND AIA FOR THE NEXT
FEW HOURS BEFORE CLEARING OCCURS. VFR CONDITIONS WILL THEN PREVAIL
THROUGH THE REMAINDER OF THE TAF PERIOD. WEST TO NORTHWEST WINDS
WILL INCREASE THIS AFTERNOON/EVENING. GUSTS TO 30-40 KTS WILL BE
POSSIBLE ACROSS SOUTHEAST WYOMING THROUGH THE EARLY EVENING.


&&

.FIRE WEATHER...
ISSUED AT 215 AM MST SAT FEB 13 2016

NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND WITH COOL TO MILD
TEMPERATURES AND RESIDUAL SNOW COVER. AFTER A BRIEF COOL
DOWN...WARMER TEMPERATURES WILL RETURN TO THE AREA BY THE MIDDLE
OF NEXT WEEK WITH HIGH TEMPERATURES 15 TO 20 DEGREES ABOVE NORMAL.
DAYTIME RELATIVE HUMIDITIES WILL TREND LOWER BY WEDNESDAY AND
THURSDAY WITH VALUES BETWEEN 20 TO 30 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...HIGH WIND WARNING UNTIL 9 AM MST SUNDAY FOR WYZ110-116-117.

     HIGH WIND WARNING UNTIL 9 PM MST THIS EVENING FOR WYZ106.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...RUBIN
AVIATION...ZF
FIRE WEATHER...TJT


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