Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 240933
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
333 AM MDT FRI OCT 24 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

IMAGERY SHOWS FLAT RIDGING WITH BROAD TROFFING TO BOTH THE WEST AND
EAST. VERY STRONG JET OFF TO THE N AND ACROSS THE BORDER REGION OF
THE NW CONUS AND CA. AT THE SFC...WEAK TROF ACROSS NRN ROCKIES AND
ACROSS THE NRN PLAINS W/ A WEAK FRONT SPLITTING MT THEN SWD THRU ERN
ID AND EVENTUALLY INTO NV.

STRONG WINDS AND SOME MOUNTAIN WAVE ACTION PINNED AND BREAKING JUST
EAST OF THE HIGH MOUNTAINS OF THE NRN ABSAROKAS TONIGHT. THESE WILL
BEGIN TO DECREASE LATER THIS MORNING. OTHERWISE...STRONG FLOW
ALOFT...WARM LL TEMPS WITH GOOD LAPSE RATES UP THRU 600 MB WILL
CONTINUE TO ALLOW FOR VARIOUS WIND SCENARIOS OVER THE NEXT COUPLE OF
DAYS. AFTERNOON WINDS WILL COME UP ACROSS THE SRN/SERN WIND
CORRIDOR...WHILE NOCTURNAL WINDS INCREASE OVER/NEAR THE LEE PORTIONS
OF THE MAJOR MOUNTAIN RANGES...WITH PERHAPS SOME OCCASIONAL SPILL
INTO THE LOWER ELEVATIONS...PARTICULARLY SATURDAY NIGHT AS
CONDITIONS BECOME MUCH MORE FAVORABLE FOR MOUNTAIN WAVE PRODUCTION.
THE UPR LVLS TRANSITION INTO A MORE SOUTHWEST UPR FLOW PATTERN BY
SATURDAY WITH THE APPROACHING TROF AXIS...AND MOISTURE WILL START
TO FEED INTO THE WRN FA ALONG WITH INCREASING VORTICITY AND LIFT.
THIS WILL PUSH A COLD FRONT THRU AND ALLOW BOTH RAIN AND SNOW
SHOWERS TO DEVELOP SAT NIGHT AND SPREAD ACROSS MUCH OF THE WRN FA
THRU THE REST OF THE DAY ON SUNDAY. ATTM...DEEP RELATIVELY WARM
TEMPS WILL KEEP THE SNOW ON THE WET AND ON THE LOWER END OF THE
ACCUMULATION SCALE...MAXING OUT AT 6 INCHES OVER THE HIGHEST
PEAKS.

.LONG TERM...MONDAY THROUGH FRIDAY

MONDAY WILL SEE THE WEATHER SYSTEM PASS THROUGH WY PRODUCING
SCATTERED RAIN SHOWERS WITH SNOW FOR MOST MOUNTAINS. BRISK WIND IN
PLACES AND COOL HIGH TEMPS. THE SHOWERS END MONDAY EVENING. TUESDAY
LOOKS DRY FOR MOST AREAS...ISOLATED SHOWERS MAY DEVELOP OVER THE NW
WY MOUNTAINS LATE TUE PM WITH INCREASING SHOWERS IN THE NW WY
MOUNTAINS TUE NIGHT. THE NEXT WEATHER SYSTEM PASSES THROUGH THE
REGION ON WEDNESDAY. A CHANCE OF RAIN SHOWERS IN THE WEST WITH SNOW
IN THE HIGHER MOUNTAINS. EAST OF THE DIVIDE...ISOLATED SHOWERS AT
BEST WITH SOME RAIN AND SNOW SHOWERS IN THE BIGHORN MOUNTAINS. THE
PRECIP ENDS WED NIGHT. AS FOR NEXT THURSDAY AND FRIDAY...THE ECMWF
MODEL IS DRY WITH UPPER RIDGE OVER THE REGION. THE GFS HAS THURSDAY
DRY BUT THEN HAS SOME PRECIP IN THE WEST ON FRIDAY AHEAD OF THE NEXT
WEATHER SYSTEM. THIS MAY BE TOO FAST AND WILL NOT ADD ANY PRECIP TO
THE WEST AT THIS TIME. HIGH TEMPS TO BE ON THE COOL SIDE TUESDAY
WITH ONLY SLIGHT WARMING ON WED. NEXT THURSDAY AND FRIDAY WILL BE
MILDER.

&&

.AVIATION.../12Z ISSUANCE/

CONCERN TODAY AGAIN WILL BE CONSIDERABLE MOUNTAIN TURBULENCE WITH
STRONG MOUNTAIN TOP WINDS...ESPECIALLY THIS MORNING. LLWS ON THE LEE
SIDE OF MOUNTAIN RANGES IS EXPECTED THIS MORNING AT COD AND
LND...BUT IT IS EXPECTED TO IMPROVE THROUGH THE MORNING HOURS.
CONSIDERABLE HIGH AND MID LEVEL CLOUDINESS THIS MORNING ARE EXPECTED
TO WILL BECOME MAINLY SKC BETWEEN 20Z AND 00Z. THERE COULD BE
ISOLATED SHOWER ACTIVITY OVER EXTREME NW WYOMING THIS MORNING...BUT
SHOULD NOT IMPACT COD OR JAC. THUS VFR AND DRY CONDITIONS WILL OCCUR
AT AREA TERMINALS THROUGH TAF VALID PERIOD...WITH BREEZY TO WINDY
CONDITIONS BEING THE MAIN CONCERN TODAY.

PLEASE SEE THE AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON
TURBULENCE FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER WILL BECOME SOMEWHAT ENHANCED TODAY THROUGH
SATURDAY...PRIMARILY ACROSS THE NATRONA COUNTY TODAY...THEN OVER
MOST BASINS AND VALLEYS EAST OF THE DIVIDE ON SATURDAY. MINIMUM RH
VALUES ACROSS THESE AREAS WILL FALL INTO THE MID AND UPPER TEENS
WHILE WINDS INCREASE OUT OF THE SOUTHWEST TO 15 TO 25 MPH WITH
HIGHER GUSTS AT TIMES. SUNDAY...MOISTURE WILL INCREASE ACROSS THE
ENTIRE REGION WITH A BETTER CHANCE FOR SHOWERS ACROSS THE NORTH AND
WEST...LOWERING FIRE DANGER ONCE AGAIN.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...BRAUN
LONG TERM...AR
AVIATION...WM
FIRE WEATHER...BRAUN





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