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000
FXUS65 KCYS 232145
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
345 PM MDT THU MAY 23 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 300 PM MDT THU MAY 23 2013

FOG TOOK MUCH OF THE DAY TO ERODE ALONG THE SOUTHERN LARAMIE RANGE
BUT MOST OF IT IS FINALLY GONE. AT THIS TIME THE SUMMIT WEBCAM
SHOWING SOME LINGERING FOG BUT IT IS NO LONGER DENSE AND IS
EXPECTED TO MIX OUT COMPLETELY OVER THE NEXT FEW HOURS. THE
QUESTION IS IF...OR MAYBE WHEN WILL THE FOG SET BACK IN. MODELS DO
SHOW MOISTURE HUGGING THE LARAMIE RANGE THROUGH MUCH OF TONIGHT
ALTHOUGH THE UPSLOPE FLOW WILL WEAKEN THROUGH THE NIGHT AS THE LOW
LEVEL JET SLIDE EAST INTO THE NEBRASKA PANHANDLE. WINDS SHOULD
TURN TO THE SOUTHWEST AROUND SUNRISE WITH DRY AIR QUICKLY ERODING
ANY LOW CLOUDS AND FOG. MAINLY LOOKING AT LOW STRATUS EAST OF THE
LARAMIE RANGE BUT SOME PATCHY FOG POSSIBLE TONIGHT.

LARGE TEMPERATURE AND PRESSURE DIFFERENCE CURRENTLY DRIVING WINDS
ACROSS CONVERSE COUNTY AND ALBANY COUNTIES. SUSTAINED WINDS OF 40
MPH WITH GUSTS OVER 50 MPH OCCURRING AT LARAMIE AND DOUGLAS. THESE
WINDS WILL CONTINUE THROUGH THE AFTERNOON INTO POSSIBLY INTO EARLY
EVENING AS THE STRONG GRADIENT RELAXES AND THE MAIN CORE OF THE
LOW LEVEL JET SHIFTS EAST. WILL BE CLOSE TO HIGH WIND WARNING
CRITERIA UNTIL WINDS DO RELAX. THE OTHER WIND CONCERN IS OVER THE
NEBRASKA PANHANDLE TONIGHT. MODELS SHOWING 50 TO 60 KT WINDS BELOW
A STRONG LOW LEVEL INVERSION. STRONGEST WINDS WILL BE OVER
NORTHERN PORTIONS OF THE PANHANDLE WHERE 50 MPH WIND GUSTS SHOULD
REACH THE SURFACE. MAIN CONCERN IS WITH SUCH STRONG WINDS BELOW
THE INVERSION THAT THESE WINDS COULD BE DIRECTED TO THE SURFACE.
SHOULD THIS OCCUR...A HIGH WIND WARNING WOULD BE NEEDED AND MAY
NEED TO ADD AN ADVISORY TO SOUTHERN PORTIONS OF THE PANHANDLE.

TURNING TO FRIDAY...SKIES WILL CLEAR FROM WEST TO EAST THROUGH THE
DAY WITH MUCH WARMER TEMPERATURES ACROSS THE FORECAST AREA. WILL
SEE SOME 80S OVER EASTERN PORTIONS OF THE AREA...ALTHOUGH IT
DEPENDS HOW FAST THE CLEARING OCCURS OVER THE PANHANDLE. THERE IS
A CHANCE FOR THUNDERSTORMS IN THE PANHANDLE FRIDAY AFTERNOON. NOT
THE BEST SET UP BUT COULD SEE THUNDERSTORMS DEVELOP ALONG A
SURFACE MOISTURE DISCONTINUITY. MODELS STILL SHOWING 2000 PLUS
J/KG SURFACE BASED CAPE AND THE NAM AND GFS BOTH MODEL SOUNDING
NOW SHOWING THE CAP BREAKING...WHICH IS DIFFERENT FROM PREVIOUS
RUN. MODEL SOUNDINGS SHOWING 0-6 KM BULK SHEAR VALUES 40-50 KTS...
SUPPORTIVE OF SUPERCELL THUNDERSTORMS CAPABLE OF PRODUCING LARGE
HAIL. WITH A BOUNDARY IN PLACE ISOLATED TORNADOES NOT OUT OF THE
QUESTION. STILL LOOKING LIKE THE MOISTURE BOUNDARY WILL RETREAT TO
THE WEST...SIMILAR TO A RETREATING DRY LINE LIKE OCCUR IN WEST
TEXAS THIS TIME OF YEAR. ALTHOUGH THE CAP WILL STRENGTHEN DURING
THE EVENING HOURS...THUNDERSTORM COULD ACTUALLY DEVELOP WESTWARD
FRIDAY EVENING. NOT LIKELY...BUT SOMETHING TO WATCH. ANOTHER
CHANCE FOR THUNDERSTORMS SATURDAY AFTERNOON IN THE NEBRASKA
PANHANDLE.


.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 300 PM MDT THU MAY 23 2013

UPPER TROF WILL HOLD OVER THE PACIFIC NW SUNDAY THROUGH TUESDAY
KEEPING THE CWA UNDER A GENERALLY SW FLOW ALOFT. WEAK IMPULSES
EMANATING FROM THE BASE OF THIS TROF WILL MOVE ACROSS THE CWA AND
LIKELY HELP TO SET OFF SOME AFTERNOON AND EVENING CONVECTION
MAINLY OVER THE PLAINS. SUNDAY LOOKING MAINLY DRY FOR NOW THEN
SOME UPTICK MONDAY AND TUESDAY. UPPER TROF WILL THEN MOVE EAST AND
ACROSS THE REGION WEDNESDAY. GFS BRINGS IT MORE BODILY ACROSS THE
REGION AND MORE QPF WHILE ECMWF SPLITS THE ENERGY...CUTTING OFF AN
UPPER LOW OVER NORTHERN MEXICO THUS HAVING LESS QPF OVER THE CWA.
EITHER WAY AT LEAST WIDELY SCATTERED SHOWERS AND A FEW STORMS LOOK A
DECENT BET WEDNESDAY BEFORE DRYING ON THURSDAY. TEMPERATURES WARM
THROUGH THE WEEKEND INTO MONDAY THEN TRENDING DOWN A BIT TUESDAY
AND WEDS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1125 AM MDT THU MAY 23 2013

AREA OF MVFR TO IFR CIGS WILL LIKELY PERSIST THROUGH EARLY FRIDAY
JUST EAST OF THE LARAMIE RANGE...BREAKING FOR A TIME THIS AFTERNOON
OVER THE PANHANDLE BEFORE RETURNING TONIGHT.  FOG...DENSE AT
TIMES...WILL ALSO PERSIST IN THE KCYS VCTY DUE TO MOIST SOUTH WINDS
RIDING UP THE CHEYENNE RIDGE.  A FEW SHOWERS POSSIBLE OVER THE MTNS
THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT THU MAY 23 2013

CONDITIONS WILL VARY ACROSS THE FORECAST AREA THE NEXT FEW DAY
WITH MOSTLY DRY AND BREEZY CONDITIONS WEST WITH LESS WIND EAST
AND HIGHER CHANCES FOR THUNDERSTORMS. HUMIDITY VALUES WILL
DROP BELOW 20 PERCENT IN THE AFTERNOON THROUGH THIS WEEKEND FOR
LOWER ELEVATIONS WEST OF THE LARAMIE RANGE AND AS LOW AS 10 PERCENT
IN THE RAWLINS AREA. THERE WILL BE SMALL CHANCES FOR AFTERNOON
THUNDERSTORMS MAINLY OVER THE NEBRASKA PANHANDLE THROUGH THE
WEEKEND.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...WIND ADVISORY FROM 9 PM THIS EVENING TO 6 AM MDT FRIDAY FOR
     NEZ002-003-095-096.

&&

$$

SHORT TERM...LIEBL
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...LIEBL