Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 172030
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
230 PM MDT THU APR 17 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 230 PM MDT THU APR 17 2014

MID/UPPER LEVEL TROUGH CONTINUES TO MOVE EAST INTO THE CENTRAL
PLAINS WITH UPPER RIDGE ALONG THE WEST COAST MAINTAINING A
NORTHWESTERLY FLOW ACROSS OUR REGION THIS AFTERNOON.  CLOSER TO THE
SURFACE A BROAD HIGH PRESSURE RIDGE TO OUR EAST IS PRODUCING A
MODERATE SOUTHEAST TO SOUTHWESTERLY FLOW ACROSS MUCH OF SE WYOMING
AND WESTERN NEBRASKA THIS AFTERNOON WITH THE USUALLY WINDIER SPOTS
SUCH AS ARLINGTON AND RAWLINS GETTING PERIODIC GUSTS 30 TO 40 MPH.
MODELS CONTINUE TO HINT AT A NOCTURNAL LOW LEVEL JET SETTING UP
ACROSS OUR EASTERN ZONES WITH 15 TO 25 MPH WINDS PROJECTED LATE
TONIGHT INTO TOMORROW MORNING.

THERE MIGHT BE JUST ENOUGH MOISTURE AROUND ON FRIDAY TO GET A FEW
SHOWERS/ISOLATED THUNDERSTORMS OVER THE WESTERN AREAS IN THE
MOUNTAINS DURING THE AFTERNOON...SO WE CONTINUED TO CARRY SOME SMALL
POPS TOMORROW AFTERNOON FOR THAT.  OTHERWISE WE CONTINUE TO WATCH
THE NEXT SYSTEM COMING IN FROM THE WEST ON SATURDAY WHEN THE ECMWF
AND GFS BOTH ADVERTISE A WEAKENING UPPER LOW (CURRENTLY APPROACHING
SOUTHERN CALIFORNIA) TO MOVE ACROSS NORTHERN COLORADO.  AT THE SAME
TIME...A WEAKENING FRONTAL BOUNDARY WILL STALL ACROSS OUR EASTERN
ZONES.  WE CONTINUED THE TRENDS OF THE PREVIOUS FORECAST PACKAGE
BRINGING POPS UP ACROSS THE SOUTHWESTERN HALF OF THE FORECAST AREA
SATURDAY WITH LOWER POPS OVER MUCH OF THE PANHANDLE WHERE MODEL
SOUNDINGS INDICATE A MORE STABLE EASTERLY BOUNDARY LAYER FLOW
CONTINUING WELL INTO SATURDAY AFTERNOON.  THERE MAY BE SOME ISOLATED
THUNDERSTORMS SATURDAY AND WE MAINTAINED SLIGHT CHANCE THUNDER
WORDING ALONG WITH CHANCE FOR MOSTLY SHOWERS ON SATURDAY.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 230 PM MDT THU APR 17 2014

A FEW SHOWERS STILL POSSIBLE NEAR THE COLORADO BORDER SAT EVENING
ON THE NORTHERN PERIPHERY OF AN UPPER SYSTEM PASSING INTO THE
SOUTHERN PLAINS. A SECONDARY IMPULSE ON SUNDAY MAY INTERACT WITH A
BIT OF INSTABILITY TO SET OFF WIDELY SCATTERED SHOWERS AND A FEW
WEAK STORMS AGAIN NEAR THE COLORADO BORDER INTO SUNDAY EVENING.
SIMILAR PATTERN FOR MONDAY WITH SOME INSTABILITY MOVING UP THE
HIGH PLAINS AIDING IN A BIT OF CONVECTION SUNDAY AFTERNOON. MILD
AND MAINLY DRY WEATHER FOR TUESDAY AHEAD OF THE NEXT SIGNIFICANT
UPPER TROF THAT WILL MOVE ONSHORE ALONG THE WEST COAST BY THE END
OF THE DAY. THIS SYSTEM SHOULD ACQUIRE A NEGATIVE TILT WEDS AS IT
MOVES INTO THE NORTHERN ROCKIES AND NORTHERN PLAINS. DRY SLOTTING
AHEAD OF THIS SYSTEM SHOULD INHIBIT PCPN OVER MOST OF THE CWA WEDS
BUT RATHER BREEZY CONDITIONS LIKELY. COOLER THURSDAY AS AN
ASSOCIATED PACIFIC FRONT PASSES ACROSS LATE WEDS WITH WIDELY
SCATTERED SHOWERS OVER MAINLY THE MTNS AND NORTHERN PARTS OF THE
CWA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 230 PM MDT THU APR 17 2014

LAST PATCH OF LOW CLOUDS GRADUALLY ERODING SHORTLY BEFORE 3 PM OVER
THE CHADRON...ALLIANCE AND SIDNEY AREAS.  OVERNIGHT...VFR FLIGHT
CATEGORIES EXPECTED AT ALL AIRPORTS IN SE WYOMING AND ALONG THE
WESTERN NEBRASKA PANHANDLE INTO THE NEXT 24 HOURS.  MAIN ISSUE WILL
BE GUSTY WINDS TONIGHT IN THE PANHANDLE WHERE THE MODELS ARE
SUGGESTING A 30 KT LOW LEVEL JET WILL SET UP WHICH SUGGESTS WE
ADVERTISE WINDS 15G30KT POSSIBLE AT A FEW OF THE AIRPORTS IN THE
EAST NOT SHELTERED BY TERRAIN.

&&

.FIRE WEATHER...
ISSUED AT 230 PM MDT THU APR 17 2014

MAIN FIRE WEATHER CONCERNS WILL BE ON FRIDAY AS TEMPERATURES WILL
BE AT THEIR WARMEST FOR THE PERIOD INTO EARLY NEXT WEEK. WINDS
WILL BE STRONGEST OVER WESTERN DISTRICTS BUT RHS WILL BE THE LOWEST
OVER THE PLAINS. DO NOT EXPECT RED FLAG CONDITIONS AS FUELS NOT
READY OUT WEST AND OVER EASTERN AREAS WINDS WILL BE SOMEWHAT
LIGHTER. STILL ELEVATED FIRE CONDITIONS FOR A TIME FRIDAY AFTERNOON.
COOL FRONT WILL PASS ACROSS LATE FRIDAY WITH MILDER CONDITIONS AND
WIDELY SCTD SHOWERS AND A FEW TSTRMS OVER THE WEEKEND.

&&

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

$$

SHORT TERM...GARMON/TJT
LONG TERM...RE
AVIATION...GARMON/TJT
FIRE WEATHER...RE




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