Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 231654
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1054 AM MDT WED APR 23 2014

.UPDATE...
ISSUED AT 1052 AM MDT WED APR 23 2014

SEEING WINDS APPROACHING ADVISORY CRITERIA AT VARIOUS LOCATIONS
OUT IN THE PANHANDLE LATE THIS MORNING. WITH THE UPPER CLOUDINESS
MOVING EAST...SHOULD SEE DEEPER MIXING THIS AFTERNOON. WENT AHEAD
WITH A WIND ADVISORY FOR MUCH OF THE PANHANDLE THROUGH 6PM THIS
AFTERNOON. UPDATES HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 310 AM MDT WED APR 23 2014

WINDY AND DRY DAYS WILL DOMINATE THE WEATHER THROUGH THE SHORT
TERM. WATER VAPOR IMAGERY SHOWS THE UPPER LEVEL TROUGH PUSHING
ACROSS WESTERN WY. THERE HAVE BEEN A FEW SHOWERS ACROSS WESTERN
CARBON COUNTY WITH WIND GUSTS OF 45-55 MPH. COLD FRONT IS
CURRENTLY ACROSS CARBON COUNTY TOO. THE MODELS SHOW THIS FRONT
MOVING EASTWARD ACROSS THE REMAINDER OF THE CWA THROUGH THE
MORNING. WEST WINDS BEHIND THE FRONT WILL INCREASE BY LATE MORNING
DUE TO THE COMBINATION OF EXCELLENT MIXING AND QG SUBSIDENCE. THE
850MB CAG-CPR GRADIENT INCREASES TO AROUND 50 METERS BY 18Z AND
WITH 1 KM AGL WIND OF 40-45 KTS...COULD SEE A FEW GUST APPROACHING
50 MPH DURING THE AFTN. FURTHER EAST INTO THE NEBRASKA PANHANDLE
GUSTS WILL LIKELY REMAIN BELOW 40 KTS. WITH GOOD MOMENTUM TRANSFER
FROM ALOFT...WILL SEE DEWPOINTS FALL SUBSTANTIALLY IN THE AFTN.
LOWERED DEWPOINTS IN THE GRIDS AND NOW GETTING MIN RH VALUES OF
20-25 PERCENT. SINCE SPC HAS THE PANHANDLE IN AN ELEVATED FIRE
WEATHER THREAT THIS AFTN...MADE A MENTION OF THIS IN THE FWF.
PRECIP CHANCES WILL BE SLIM TODAY WITH THE STRONG SUBSIDENCE AND
LACK OF SFC INSTABILITY. TEMPS WILL BE AROUND 10 DEGREES COOLER
TODAY BEHIND THE FRONT.

UPPER TROUGH AXIS IS POSITIONED OVER THE NORTHERN PLAINS BY THURS
MORNING WITH NORTHWESTERLY FLOW ALOFT OVER THE CWA. WINDS WILL
DECREASE TONIGHT WITH THE LOSS OF DAYTIME MIXING...ONLY TO RAMP UP
AGAIN BY LATE THURS MORNING. DO NOT BELIEVE THAT WINDS WILL BE
QUITE AS STRONG DURING THE DAY ON THURS...HOWEVER GUSTS TO 35-40
KTS WILL STILL BE COMMON...ESPECIALLY ACROSS SOUTHEAST WY. RH
VALUES DROP TO 15-20 PERCENT OVER THE PANHANDLE SO ANOTHER ELEVATED
FIRE WEATHER THREAT IS EXPECTED. SHORTWAVE RIDGE MOVES OVERHEAD ON
FRI WITH SFC WINDS BECOMING SOUTH-TO-SOUTHEAST AS PRESSURE FALLS
OCCUR TO THE WEST OF THE REGION. LI VALUES AROUND 0C WILL PROMOTE
A BETTER COVERAGE OF AFTN CUMULUS.

.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 310 AM MDT WED APR 23 2014

FRIDAY NIGHT...FLOW ALOFT BACKS TO SOUTHWEST IN ADVANCE OF STRONG
SHORTWAVE TROUGH ALOFT APPROACHING FROM THE DESERT SOUTHWEST. STILL
RELATIVELY MILD IN THE WARM SECTOR AHEAD OF THE NEXT COLD FRONT.
CHANCE OF SHOWERS NORTH AND WEST OF RAWLINS LATE.

SATURDAY...NEGATIVELY TILTED SHORTWAVE TROUGH ALOFT MOVES TO THE
FOUR CORNERS BY LATE AFTERNOON WITH OUR COUNTIES IN THE WARM SECTOR.
LOOKS LIKE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
IN THE AFTERNOON AND EVENING...MOST NUMEROUS ALONG A SURFACE TROUGH
AND CONVERGENCE AXIS FROM CASPER TO LARAMIE.

SUNDAY...MODELS SIMILAR IN DEPICTING THE STRONG CLOSED UPPER TROUGH
MOVING SLOWLY NORTHEAST TO NORTHWEST KANSAS IN THE AFTERNOON WITH
ATTENDANT SURFACE LOW PRESSURE STRENGTHENING ACROSS WESTERN KANSAS.
MODELS SHOW COPIOUS AMOUNTS OF QPF...WHICH SEEMS PLAUSIBLE...WITH
INFLUX OF LOW LEVEL MOISTURE LIKELY FROM THE GULF OF MEXICO AND
MOISTURE LADEN STORM SYSTEM. PROGGED THICKNESSES SUGGEST MOSTLY RAIN
AT LOWER ELEVATIONS WITH SNOW IN THE MOUNTAINS. IN ANY EVENT...IT
WILL BE BLUSTERY AND COOL WITH AT LEAST SCATTERED COVERAGE OF
SHOWERS.

MONDAY...THE UPPER TROUGH MOVES SLOWLY EASTWARD...THOUGH STILL
WRAPAROUND SHOWERS POSSIBLE ESPECIALLY OVER OUR NORTHERN COUNTIES
WHERE UPSLOPE WILL AID LIFT. COOL AND BLUSTERY BASED ON PROGGED
THICKNESSES.

TUESDAY...DRYING OUT PERIOD AS THE UPPER TROUGH MOVES FAR ENOUGH
EAST OF OUR COUNTIES...THOUGH COOL NORTH FLOW ALOFT WILL RETARD AND
LIMIT WARMING TREND. CONTINUED BREEZY TO WINDY PER PROGGED LOW AND
MID LEVEL GRADIENTS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 529 AM MDT WED APR 23 2014

VFR WITH SCATTERED TO BROKEN CLOUDS AT OR ABOVE 9000 FEET AGL.
WEST WIND 20 TO 30 KNOTS GUSTING TO 45 KNOTS THROUGH 00Z...THEN
WINDS SUBSIDING IN THE EVENING TO AROUND 10 KNOTS. LOCALIZED
MOUNTAIN WAVE TURBULENCE AND LEE EDDY EFFECTS THROUGH THIS
AFTERNOON.


&&

.FIRE WEATHER...
ISSUED AT 310 AM MDT WED APR 23 2014

A COLD FRONT WILL PUSH ACROSS THE REGION THIS MORNING WITH WINDY
AND DRY CONDITIONS BEHIND IT. MINIMUM RELATIVE HUMIDITY VALUES
THIS AFTERNOON WILL BE 20 TO 25 PERCENT AND WEST WIND GUSTS WILL
REACH 35 TO 40 MPH. CONDITIONS WILL BE VERY SIMILAR ON
THURSDAY AFTERNOON...WITH RELATIVE HUMIDITY VALUES OF 15 TO 20
PERCENT. AN ELEVATED FIRE WEATHER THREAT IS THUS WARRANTED OVER
THE NEXT TWO AFTERNOONS ACROSS THE WESTERN NEBRASKA PANHANDLE
WHERE FUELS ARE STILL DRY ENOUGH TO SUPPORT FIRE GROWTH.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR NEZ019>021-054-055-
     095-096.

&&

$$

UPDATE...CLAYCOMB
SHORT TERM...FINCH
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...FINCH






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