Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 260547
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1147 PM MDT SAT JUL 25 2015

.UPDATE...
ISSUED AT 848 PM MDT SAT JUL 25 2015

A FEW SHOWERS AND T-STORMS POPPED UP LATE IN THE AFTERNOON AND
EARLY EVENING...BUT HAVE SINCE BEEN ON THE STEADY DOWNTURN WITH
SUNSET. A NUMBER OF OUTFLOW BOUNDARIES ARE SCATTERED ACROSS THE
CWA AT THIS HOUR...WITH A COUPLE LAID UP AGAINST THE LARAMIE
RANGE. ALTHOUGH CONFIDENCE IS HIGHER THAT CONDITIONS WILL REMAIN
DRY THE REST OF THE NIGHT...CANNOT COMPLETELY RULE OUT A SHOWER
DEVELOPING OFF ONE OF THE BOUNDARIES OVER THE NEXT HOUR OR TWO.
OTHERWISE...THINK QUIET CONDITIONS WILL PREVAIL THE REST OF
TONIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM MDT SAT JUL 25 2015

FORECAST CHALLENGES CONTINUE TO DEAL WITH TEMPERATURES AND FIRE
WEATHER CONDITIONS THROUGH THE SHORT TERM.

CURRENTLY...SURFACE COLD FRONT BEGINNING TO MOVE INTO EASTERN
WASHINGTON STATE THIS AFTERNOON. SURFACE HIGH PRESSURE RESIDES
OVER THE ROCKIES THIS AFTERNOON. LATEST CRAIG TO CASPER SURFACE
GRADIENT STANDS AT 3.3MBS THIS AFTERNOON AT 1 PM. WINDS ARE FAIRLY
LIGHT ACROSS THE AREA...THOUGH WE ARE SEEING SOME GUSTS TO 25 MPH
UP BY DOUGLAS. TEMPERATURES HAVE CLIMBED INTO THE MID AND UPPER
80S FOR MANY LOCATIONS SO FAR TODAY. LOOKS LIKE WE ARE NOW MIXING
UP TO AROUND 500MBS BASED ON THOSE WINDS AT DOUGLAS. SO...NEAR
CRITICAL FIRE WEATHER CONDITIONS TO CONTINUE THIS AFTERNOON.

LATEST NAM AND GFS FORECAST SOUNDINGS SHOWING SLIGHTLY STRONGER
WINDS FOR SUNDAY. BOTH ARE SHOWING WINDS AT THE MIXED LAYER AROUND
30KTS SUNDAY AFTERNOON...UP ABOUT 5-10KTS FROM WHAT WE ARE SEEING
TODAY. DECIDED TO ISSUE A FIRE WEATHER WATCH FOR FWZ 301...302
AND 304 WHERE FUELS ARE RECEPTIVE TO LARGE FIRE GROWTH.
TEMPERATURES ARE FORECAST TO BE WARMER SUNDAY OVER TODAY...SO WE
COULD MIX SLIGHTLY HIGHER THAN WE HAVE TODAY.

BEST FIRE WEATHER DAY LOOKS TO BE SUNDAY NIGHT INTO MONDAY NIGHT
AS THE DRY COLD FRONT APPROACHES FROM THE NORTHWEST. 700MB WINDS
INCREASE TO 30-35KTS. FORECAST SOUNDINGS FOR RAWLINS SHOWING 40-45KTS
AT THE MIXED LAYER OF 519MBS. ANOTHER HOT DAY WITH HIGHS IN THE
UPPER 80S TO LOW 90S...SO WE SHOULD DEFINITELY BE ABLE TO MIX UP
THAT HIGH. WENT AHEAD WITH A FIRE WEATHER WATCH FOR MONDAY AS
WELL.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM MDT SAT JUL 25 2015

THE GFS/ECMWF ARE IN GOOD AGREEMENT WITH A FAIRLY STRONG MID LEVEL
SHORTWAVE TRACKING ACROSS EASTERN MT INTO WESTERN ND EARLY IN THE
PERIOD. THIS SHOULD PUSH A SURFACE COLD FRONT SOUTH ACROSS THE CWA
ON TUE...WITH H7 TEMPS FALLING INTO THE UPPER SINGLE DIGITS DEG C
ACROSS THE NORTHERN ZONES BY 18Z. THERE DOES NOT APPEAR TO BE MUCH
OF A CHANCE OF PCPN WITH THIS FROPA GIVEN A FAIRLY DRY H7-H3 LAYER
AND THE BULK OF MID LEVEL ENERGY PASSING WELL TO THE NORTH. MODELS
SHOW COLDER AIR FILTERING INTO THE SOUTHERN LARAMIE RANGE/ADJACENT
FOOTHILLS ON TUE NIGHT/WED...SO EXPECT WEDNESDAY TO BE THE COOLEST
DAY OF THE PERIOD WITH GFS H7 TEMPS AROUND 6-8 DEG C AT CYS. BROAD
UPPER-LEVEL RIDGING SHOULD TAKE OVER THROUGH THE REMAINDER OF THE
EXTENDED FORECAST PERIOD...WITH LARGE SCALE SUBSIDENCE AND A VERY
DRY COLUMN KEEPING PCPN CHANCES ON HOLD. A WARMING TREND WILL TAKE
PLACE THROUGH THE END OF THE WEEK...WITH BOTH MEX/ECM MOS GUIDANCE
SUGGESTING AT LEAST LOWER TO MID 90S OVER THE PANHANDLE BY FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1142 PM MDT SAT JUL 25 2015

SOME JET ENERGY WILL CONTINUE TO LIFT NORTHEAST ACROSS THE AREA
TONIGHT AND TOMORROW. THIS MAY BE ENOUGH TO TRIGGER A FEW
THUNDERSTORMS AGAIN ALONG AND EAST OF THE LARAMIE RANGE SUNDAY AFTERNOON.
OTHERWISE...VFR CONDITIONS WILL PREVAIL. THE WIND WILL GENERALLY
BE FROM THE SOUTH-SOUTHEAST ALONG AND EAST OF THE LARAMIE RANGE
WITH MAINLY SOUTHWEST FLOW AT THE RWL TAF SITE.

&&

.FIRE WEATHER...
ISSUED AT 300 PM MDT SAT JUL 25 2015

HOT...DRY AND BREEZY CONDITIONS CONTINUE THROUGH AT LEAST TUESDAY
WITH DAILY CHANCES FOR CRITICAL TO NEAR CRITICAL FIRE WEATHER
CONDITIONS. BY SUNDAY AFTERNOON...THE HOTTEST TEMPERATURES OF THE
YEAR ARE EXPECTED ACROSS THE AREA. THESE HOT TEMPERATURES WILL
ALLOW WINDS TO MIX DOWN TO THE GROUND FROM VERY HIGH LEVELS OF THE
ATMOSPHERE. OUR ZONES THAT HAVE FUELS DESIGNATED RECEPTIVE TO
RAPID FIRE GROWTH WILL LIKELY SEE CRITICAL FIRE WEATHER CONDITIONS
FOR A TIME SUNDAY AFTERNOON THROUGH THE EARLY EVENING. A FIRE
WEATHER WATCH HAS BEEN POSTED FOR THESE ZONES. A MORE WIDESPREAD
WIND EVENT FOR MONDAY AS LOW PRESSURE TRACKS THROUGH
MONTANA...DRAGGING A DRY COLD FRONT INTO THE AREA MONDAY EVENING.
AHEAD OF THIS FRONT...WIND GUSTS CLOSE TO 50 MPH ARE LIKELY FOR
AREAS WEST OF THE LARAMIE RANGE...WITH WIND GUSTS TO 35 MPH ALONG
THE EAST SLOPES. CRITICAL FIRE WEATHER CONDITIONS COULD CONTINUE
INTO TUESDAY WITH GUSTY NORTHWEST WINDS BEHIND THE FRONT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...FIRE WEATHER WATCH FROM 9 AM MDT SUNDAY THROUGH SUNDAY EVENING
     FOR WYZ301-302-304.

     FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING
     FOR WYZ301-302-304-310.

NE...NONE.
&&

$$

UPDATE...RJM
SHORT TERM...GCC
LONG TERM...CLH
AVIATION...REC
FIRE WEATHER...GCC


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