Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 150539
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1139 PM MDT TUE APR 14 2015

.UPDATE...
ISSUED AT 1136 PM MDT TUE APR 14 2015

EXTENDED THE WIND HIGHLIGHTS ACROSS NORTHERN SIOUX AND DAWES
COUNTIES THROUGH 4 AM AND CANCELLED THEM EVERYWHERE ELSE ACROSS
THE PANHANDLE. CHADRON IS CURRENTLY GUSTING TO 49 KTS...AND
SOUNDINGS SHOW THE LLVL JET OF 50-55 KTS CONTINUING THROUGH LATE
TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 330 PM MDT TUE APR 14 2015

FAIRLY QUIET OVER THE CWA THIS AFTERNOON. SOME MODEST CUMULUS OVER
PARTS OF SE WY BUT DRY AIR HINDERING DEVELOPMENT. MEANWHILE UPPER
TROF CURRENTLY OVER THE PACIFIC NW WILL DIG SOUTH OVERNIGHT AND
CLOSE OFF A LOW OVER NORTHERN UTAH BY MORNING. GOOD SFC PRESSURE
GRADIENT OVER THE NEB PANHANDLE WILL KEEP WINDS UP THIS EVENING SO
WILL MAINTAIN WIND HIGHLIGHTS THERE. MOISTURE ASSOCIATED WITH THE
UPPER SYSTEM WILL SPREAD SLOWLY EAST AND SHOULD BRING A FEW
RAIN/SNOW SHOWERS TO FAR WESTERN PARTS OF THE CWA LATER TONIGHT.
OTHERWISE...A PACIFIC COLD FRONT WILL MOVE ACROSS THE CWA LATE
TONIGHT INTO WEDS MORNING WITH MUCH COOLER AIR MOVING IN BEHIND
IT. RAIN AND HIGHER ELEV SNOW STILL LOOKS TO SPREAD SLOWLY EAST
ACROSS THE CWA WEDS AS THE UPPER LOW DRIFTS SE ACROSS UTAH WITH
FAIRLY WIDESPREAD PCPN FOR WEDS NIGHT. ACCUMULATING SNOWS STILL
LOOK TO BE MAINLY OVER THE MTNS BUT SOME LIGHT ACCUMULATIONS
SHOULD OCCUR OVER ADJACENT AREAS OF THE PLAINS LATER WEDS NIGHT.
COOL THURSDAY AND THURSDAY NIGHT WITH PCPN MAINLY OVER THE SRN
PART OF THE CWA AS THE UPPER LOW MEANDERS AROUND THE 4 CORNERS
AREA. RAIN/SNOW LINE TRICKY AS NOT A LOT OF COLD AIR WITH THIS
SYSTEM. HOPEFULLY SOME DECENT PCPN AMOUNTS WILL FALL OVER MANY
AREAS TO ALLEVIATE THE DRY CONDITIONS SO FAR THIS SPRING.

.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 330 PM MDT TUE APR 14 2015

THE FORECAST CHALLENGES WILL FOCUS THE FIRST HALF OF THE LONG TERM
WITH MODEL TIMING AND POSITION DIFFERENCES HANDLING THE SOUTHERN
STREAM UPPER LOW AND TROUGH. THE ECMWF...NAM AND CANADIAN MODELS
ARE SIMILAR WITH THE LOCATION OF THE CLOSED LOW OVER THE FOUR CORNERS
AT 12Z FRIDAY. THE GFS SHOWS A MORE ELONGATED LOW WITH ITS CENTER
OVER EAST CENTRAL COLORADO. THE GFS IS THE OUTLIER AS IT MOVES THE
LOW INTO THE CENTRAL/SOUTHERN PLAINS BY SATURDAY. THE OTHER MODELS
SLOWLY DRIFT THE SYSTEM EAST AND WEAKEN IT TO A OPEN WAVE. MEANWHILE...
THE NORTHERN STREAM WILL BE PROGRESSIVE DEPICTING ONE TROUGH PASSAGE
BYPASSING TO THE NORTH FRIDAY...TRANSITORY RIDGE OVERHEAD SATURDAY...
FOLLOWED BY A STRONGER TROUGH IMPACTING THE NORTHERN PLAINS AND UPPER
MIDWEST LATE SUNDAY AND MONDAY. WILL PUT MORE EMPHASIS ON THE
ECMWF/CANADIAN AND ENSEMBLES.

WITH REGARDS TO SENSIBLE WEATHER...WILL HOLD ONTO CHANCES FOR LOWER
ELEVATION RAIN/MOUNTAIN SNOW MOST OF THE CWA THIS WEEKEND. GENERALLY
LOOKING AT LIGHT QPF AMOUNTS...WITH BETWEEN 0.10 AND 0.50 INCHES.
TEMPERATURES WILL AVERAGE BELOW SEASONAL NORMALS FRIDAY...WITH
NEAR NORMAL VALUES SATURDAY. A COLD FRONT WILL PUSH THROUGH THE
CWA EARLY SUNDAY...RESULTING IN BELOW AVERAGE TEMPERATURES ONCE
AGAIN. EARLY NEXT WEEK...THE CWA WILL BE POSITIONED BETWEEN A
TROUGH TO THE NORTHEAST AND RIDGE OVER THE GREAT BASIN. THE RESULT
WILL BE DRY WEST TO NORTHWEST FLOW ALOFT AND MILDER TEMPERATURES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1044 PM MDT TUE APR 14 2015

NEBRASKA TAFS...GUSTY SOUTH TO SOUTHEAST WINDS OVERNIGHT.

VFR PREVAILS...EXCEPT FOR MVFR CEILINGS AT SIDNEY BETWEEN 10Z AND
15Z. PACIFIC COLD FRONT PASSES NEBRASKA TAF SITES LATE WEDNESDAY
AFTERNOON WITH WINDS BECOMING NORTHWEST AND THEN NORTH IN THE
EVENING. CEILINGS LOWERING IN THE AFTERNOON WITH ISOLATED TO
SCATTERED SHOWERS DEVELOPING WEDNESDAY AFTERNOON...WITH ISOLATED
THUNDERSTORMS AT SIDNEY AFTER 21Z.

WYOMING TAFS...SOUTHWEST WINDS GUSTING NEAR 30 TO 40 KNOTS AT
RAWLINS THROUGH 15Z WITH VFR PREVAILING AND CEILINGS JUST ABOVE
MVFR FROM 06Z TO 15Z. PACIFIC COLD FRONTAL PASSAGE AFTER 15Z AT
RAWLINS WITH WINDS VEERING TO NORTHWEST AND GUSTING NEAR 30 KNOTS
AND ISOLATED TO SCATTERED SHOWERS DEVELOPING WITH CEILINGS
LOWERING TO NEAR 4500 FEET AGL ALONG WITH MOUNTAIN OBSCUREMENT
AFTER 20Z.

AT LARAMIE AND CHEYENNE...VFR WITH WINDS SOUTH UNTIL 15Z...THEN
WEST AND NORTHWEST WITH PACIFIC COLD FRONTAL PASSAGE WITH GUSTS TO
33 KNOTS. WINDS BECOMING NORTH WEDNESDAY AFTERNOON...GUSTING TO
30 KNOTS...WITH CEILINGS LOWERING TO 3500 TO 4500 FEET...MOUNTAIN
OBSCUREMENT AND ISOLATED TO SCATTERED SHOWERS DEVELOPING ALONG
WITH VISIBILITIES IN SHOWERS FROM 3 TO 5 MILES. MVFR DEVELOPING
WEDNESDAY EVENING.


&&

.FIRE WEATHER...
ISSUED AT 754 PM MDT TUE APR 14 2015

RED FLAG WARNING EXPIRED AT 800 PM MDT AS HUMIDITIES CONTINUE
TO SLOWLY RECOVER AND WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS
WILL CONTINUE TO ALLEVIATE THROUGH THE EVENING HOURS.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...HIGH WIND WARNING UNTIL 4 AM MDT WEDNESDAY FOR NEZ002.

     WIND ADVISORY UNTIL 4 AM MDT WEDNESDAY FOR NEZ095.

&&

$$

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



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