Area Forecast Discussion
Issued by NWS Cheyenne, WY

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000
FXUS65 KCYS 270351
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
951 PM MDT SUN JUL 26 2015

.UPDATE...
ISSUED AT 934 PM MDT SUN JUL 26 2015

MINOR UPDATE TO INCLUDE MENTION OF PATCHY FOG FOR THE SOUTHERN NE
PANHANDLE AFTER 06Z. DUAL-POL RAINFALL ESTIMATES ARE IN THE AREA
OF 2-4 INCHES ROUGHLY ALONG A KIMBALL TO BROADWATER LINE FROM THE
CONVECTION EARLIER TODAY. BUFKIT SOUNDINGS APPEAR TO BE ON TRACK
WITH GOOD LLVL SATURATION OVERNIGHT...ALONG WITH CLEAR SKIES AND
LIGHT WINDS THAT ARE ALREADY TAKING SHAPE. HRRR SHOWS POCKETS OF
REDUCED VISIBILITY AS FAR WEST AS CYS...BUT BELIEVE WE WILL STAY
MIXED ENOUGH TO KEEP FOG AT BAY. HOWEVER WITH DEW POINTS STILL IN
THE MID 50S AMID SOUTHEASTERLY SFC FLOW...WILL NEED TO MONITOR.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 246 PM MDT SUN JUL 26 2015

QUITE AN ACTIVE AFTERNOON WITH SEVERE THUNDERSTORMS EAST AND NEAR
CRITICAL FIRE WEATHER CONDITIONS WEST.

CURRENTLY...WE HAVE A DRY LINE PUSHING INTO THE NEBRASKA PANHANDLE
THIS AFTERNOON. BEHIND THE DRY LINE...DEWPOINTS IN THE 20S AND 30S
ARE BEING REPORTED IN SOUTHEASTERN WYOMING. AHEAD OF THIS
LINE...DEWPOINTS IN THE MID TO UPPER 50S ARE BEING OBSERVED. OUT
WEST IN CARBON COUNTY...GETTING WIND GUSTS TO 30 MPH AT RAWLINS
AND LOW 20 MPH RANGE DOWN BY DIXON. DECIDED TO KEEP THE CURRENT
RED FLAG WARNING GOING FOR FWZ 304 THROUGH 8 PM THIS EVENING.

STRONG WIND EVENT STILL ON TRACK FOR MONDAY AS A PACIFIC LOW
PRESSURE SYSTEM TRACKS INTO WESTERN MONTANA AND NORTHWESTERN
WYOMING. LATEST NAM FORECAST SOUNDINGS SHOWING US MIXING UP TO
NEAR 500MBS MONDAY WITH FORECAST WINDS AT THIS LEVEL OF 45-50KTS.
WE COULD BE LOOKING AT SOME HIGH WIND CRITERIA...ESPECIALLY FOR
OUR WIND PRONE AREAS OF INTERSTATES 80 AND 25. PROBABLY OF MORE
SIGNIFICANCE IS WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS THAT
ARE ALMOST CERTAIN TO HAPPEN MONDAY. FORECAST MIN HUMIDITIES OF 7
TO 15 PERCENT LOOK TO BE WIDESPREAD MONDAY...ESPECIALLY WITH POOR
OVERNIGHT RECOVERIES. WENT AHEAD AND UPGRADED PREVIOUS FIRE
WEATHER WATCHES TO WARNINGS WHERE FUELS ARE REPORTED RECEPTIVE.

WHILE DEALING WITH RED FLAG CONDITIONS ACROSS SOUTHEAST
WYOMING...WE COULD BE DEALING WITH SEVERE THUNDERSTORMS IN THE
PANHANDLE AHEAD OF THAT FRONT. NAM FORECAST MOST UNSTABLE CAPE
ACROSS THE PANHANDLE MONDAY AFTERNOON FORECAST AROUND 2000J/KG.
FORECAST SHEAR 0-6KM AROUND 33KTS...CAN NOT RULE OUT SEVERE
THUNDERSTORMS OUT THERE FOR MONDAY AFTERNOON. ESPECIALLY WITH THE
TIMING OF THE FRONT MOVING THROUGH LATE AFTERNOON/EARLY EVENING.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 246 PM MDT SUN JUL 26 2015

PRETTY QUIET EXTENDED PERIOD AS THE SUBTROPICAL RIDGE REMAINS
ANCHORED NEAR THE FOUR CORNERS REGION AND KEEPS A DRY WESTERLY
MIDLVL FLOW OVER THE CWA.  TEMPS ON WED WILL BE COOL...HOWEVER WITH
A DRY AIRMASS IN PLACE...MIN RH VALUES WILL STILL DROP TO 10-15
PERCENT OVER CARBON COUNTY.  COULD BE AN ISOLATED STORM OVER THE
SOUTHERN LARAMIE RANGE DURING THE EVENING AS SOUTHEASTERLY WINDS
ACROSS THE PLAINS PRODUCES CONVERGENCE.  WE WILL SEE 5-10 DEGREES OF
WARMING FOR THURS AND THEN LITTLE CHANGE THROUGH NEXT WEEKEND.  700-
500MB FLOW REMAINS WEST NORTHWEST THROUGH SATURDAY WITH THE GFS
SHOWING PW VALUES REMAINING 0.25-0.50 INCHES...WHICH IS WELL BELOW
NORMAL FOR THIS TIME OF YEAR.  CONVECTION WILL BE REALLY STYMIED IN
THIS PATTERN.  ALTHOUGH RH VALUES WILL DROP TO BELOW CRITICAL LEVELS
TO THE WEST OF THE LARAMIE RANGE ON ALL AFTNS...THE WEAK GRADIENTS
AND WINDS WILL LIKELY KEEP FIRE WEATHER HIGHLIGHTS LIMITED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH MONDAY AFTERNOON)

VFR CONDITIONS THROUGH THE TAF PERIOD. ISOLATED THUNDERSTORMS WILL
BE POSSIBLE EARLY THIS EVENING ACROSS THE SOUTHERN NEBRASKA
PANHANDLE. THESE STORMS HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS
AND BRIEF HEAVY RAIN. TSTORMS WILL EITHER PUSH EAST OR RAPIDLY
DISSIPATE JUST AFTER SUNSET. WINDS WILL BECOME LIGHT AND VARIABLE
TONIGHT.


&&

.FIRE WEATHER...
ISSUED AT 246 PM MDT SUN JUL 26 2015

MARGINAL CRITICAL FIRE WEATHER CONDITIONS CONTINUE THIS AFTERNOON FOR
WESTERN CARBON COUNTY WITH WINDS EASING TEMPORARILY AFTER SUNSET.
WINDS BEGIN TO INCREASE AFTER MIDNIGHT TONIGHT AND WILL BECOME QUITE
STRONG MONDAY. EXPECT POOR OVERNIGHT HUMIDITY RECOVERIES...ESPECIALLY
WEST OF THE LARAMIE RANGE AS THESE WINDS INCREASE. A DRY COLD FRONT
IS STILL EXPECTED TO MOVE INTO THE AREA LATE MONDAY AFTERNOON.
AHEAD OF THIS FRONT...WIDESPREAD WIND GUSTS IN EXCESS OF 40 MPH
ARE LIKELY. COULD SEE CRITICAL FIRE WEATHER CONDITIONS CONTINUING
INTO TUESDAY AS NORTHWEST WINDS WILL REMAIN STRONG AND DRY AIR
REMAINS IN PLACE.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING FROM 9 AM TO 8 PM MDT MONDAY FOR WYZ301-302-304-
     310.

NE...NONE.
&&

$$

UPDATE...CLH
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC


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