Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 021942
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
142 PM MDT TUE SEP 2 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

DRY WEST FLOW WILL DOMINATE THE WEATHER ACROSS WESTERN AND CENTRAL
WYOMING THROUGH WEDNESDAY. LIMITED MOISTURE OVER MONTANA WILL
BRUSH THE NORTHERN MOUNTAINS WEDNESDAY AFTERNOON ALONG A COLD
FRONT AND MAY PRODUCE SOME LIGHT SHOWERS. OTHERWISE STRONGER DRY
WINDS ALOFT WILL MIX DOWN TO THE SURFACE ACROSS PORTIONS OF
SOUTHERN AND CENTRAL WYOMING WITH STRONG WIND GUSTS EARLY THIS
EVENING AND AGAIN WEDNESDAY AFTERNOON.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

AS FCST PERIOD BEGINS...UPPER LEVELS HAVE A FAST UPR SWRLY FLOW OVR
WY W/ WRN CONUS TROF ANGLED FROM SRN SASKATUAN TO NRN CALIFORNIA. SW
DISTURBANCE TRAVELLING AROUND THE BASE OF THE MAIN TROF WILL BE VERY
CLOSE TOT HE NWRN/NRN BORDER AT THIS TIME. THE SFC WILL HAVE A
QUICKLY DEEPENING LEE SIDE TROF ACROSS ERN WY WITH ASSOCIATED FRONT
JUST PUSHING INTO THE NRN/NWRN CWA.

WED NIGHT AND THURSDAY...TIGHT PRESSURE GRAD ASSOCIATED WITH THE LEE
CYCLONE WILL GET PUSHED SOUTH BY THE FRONT...ELIMINATING RED FLAG
CONDITIONS THRU THE REST OF THE FCST...PROBABLY. WITH DRY AIR IN
PLACE OVR MOST OF THE CWA AHEAD OF...AND FOR THE MOST PART BEHIND...
THE FRONT AND THE ASSOCIATED UPR LVL TROF...AND WITH NO TIME TO
RELOAD MOISTURE...LITTLE IN THE WAY OF PRECIP WILL FALL. WHAT LITTLE
MOISTURE DOES FALL WILL HAVE TO TAKE ADVANTAGE OF ELEVATION GAINS IN
THE MOUNTAINS...AND TO A LITTLE LESSER EXTENT...ALONG/NEAR SFC
FRONT/BOUNDARY AS IT MOVES INTO THE SRN FCST ZONES THROUGH THE
EVENING. THURSDAY...INASMUCH AS WED WILL BE THE WARMEST DAY OF THE
EXTENDED FCST PERIOD...THURSDAY WILL BE POST FRONTAL AND THE
COOLEST...WITH HIGHS STRUGGLING TO GET OUT OF THE 60S EVEN ACROSS
THE SRN ZONES. THE HIGHER MOUNTAINS ONLY GET TO AROUND 40 IN MANY
CASES. AGAIN...ALTHOUGH SW MID TO UPR FLOW WILL BE QUITE BRISK WITH
OCCASIONAL BLIPS OF ADDITIONAL ENERGY MOVING THRU...MOISTURE WILL BE
HELD OFF TO SRN/CNTRL UPR LEVELS FOR THE MOST PART WITH ONLY THE
HIGHER MOUNTAIN PEAKS ABLE TO REDIRECT SOME OF THIS VERTICALLY
ENOUGH TO PRODUCE A BRIEF SHOWER OR SPRINKLES. AGAIN...A SECONDARY
AREA OF VERY LIGHT PRECIP WILL BE BRIEFLY POSSIBLE OVER/NEAR SFC
FRONT NEAR THE SRN WY/CO BORDER.

FRIDAY AND BEYOND...SEASONALLY COOL AND RELATIVELY DRY. LR MDLS
TRENDING SIMILAR THRU THE REST OF THE EXTENDED PERIOD WITH ONLY A
FEW RATHER SMALL DIFFERENCES THAT DO NOT REALLY IMPACT THE FCST
SIGNIFICANTLY. AGAIN...LARGE WRN CONUS TROF SPLITS INTO STALLED SRN
BRANCH OVR THE FAR SW CONUS...WHILE THE NORTHERN PORTION TRANSLATES
QUICKLY EWD...DIVIDING THE COUNTRY INTO A LARGE RIDGE/TROF PATTERN
FROM W TO E. ADDITIONALLY...A BROAD AREA OF HIGH PRESSURE WILL FILL
IN BEHIND THE WED/THU FRONT...TAKING OVR MUCH OF THE NRN HALF OF THE
CNTRL AND WRN CONUS...SUPPRESSING MUCH AVAILABLE MOISTURE TO THE
SOUTH OF THE FA...MAKING IT TOUGH TO GET MUCH MEASURABLE PRECIP ON
THE GROUND THROUGH MOST OF THE FCST. OVERALL...EVEN WITH OCCASIONAL
BOUTS OF UPR LVL ENERGY MOVING THROUGH OVERHEAD...AND A CLIPPER TYPE
FRONTAL PASSAGE NEXT MON/TUE...AREAS FAVORED FOR A LITTLE BETTER
PRECIP POTENTIAL WILL FOLLOW SUIT AND FAVOR THE SRN ZONES
FIRST...CNTRL MOUNTAINS SECOND...THEN NRN MOUNTAINS LAST.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS WILL PREVAIL THROUGH 00Z THURSDAY. A FEW HIGH CLOUDS
WILL MOVE OVER THE NORTH IN WEST FLOW ALOFT. THE REST OF WESTERN
AND CENTRAL WYOMING WILL BE SKC. AREAS OF SOUTHWEST SURFACE WINDS
15 TO 25 KTS WITH GUSTS TO 35 KTS WILL PERSIST ACROSS THE SOUTH
AND CENTRAL AREAS THROUGH 02Z AND REDEVELOP ON WEDNESDAY AROUND
16Z.

NOTE...OBSERVATION FROM KCOD REMAINS UNAVAILABLE DUE TO EQUIPMENT
FAILURE...WAITING ON FAA TECH TO REPAIR.  TAF CONTINUED AS VFR
CONDITIONS ARE ANTICIPATED AT KCOD THROUGH THE FORECAST PERIOD.

&&

.FIRE WEATHER...

...RED FLAG CONDITIONS EXPECTED ACROSS PORTIONS OF RAWLINS...CODY
AND CASPER DISPATCH THIS EVENING AND AGAIN ON WEDNESDAY...

MUCH WARMER AND DRIER TONIGHT AND TOMORROW...IN ADDITION TO
WINDIER. VERY LOW RELATIVE HUMIDITY AND STRONG GUSTY WINDS WILL
INCREASE ACROSS THE SOUTHWEST AND CENTRAL PORTIONS OF WYOMING
CONTINUING UNTIL AROUND 8 PM MDT.  THE VERY LOW RELATIVE HUMIDITY
AND STRONG GUSTY WINDS WILL REDEVELOP AFTER NOON ON WEDNESDAY
CONTINUING UNTIL AROUND 8 PM MDT WEDNESDAY EVENING...AT WHICH TIME
A DRY COLD FRONT WILL BE DROPPING INTO NORTHERN WYOMING...SHIFTING
THE WINDS TO THE NORTH WITH WINDS REMAINING IN THE 20 TO 30 MPH
RANGE WITH GUSTS OVER 45 MPH IN AREAS PRONE TO NORTHERLY WIND. RED
FLAG WARNING IS IN EFFECT UNTIL 8 PM MDT TODAY FOR WIND AND LOW
RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 279...280... 283 AND 289.
RED FLAG WARNING AGAIN IN EFFECT FROM NOON TO 8 PM MDT WEDNESDAY
FOR WIND AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES
279...280...283 AND 289.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING WYZ279-280-283-289.

RED FLAG WARNING FROM NOON TO 8 PM MDT WEDNESDAY
WYZ279-280-283-289.

&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRAUN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER







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