Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 272124
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
324 PM MDT MON OCT 27 2014

.SHORT TERM...TONIGHT THROUGH MONDAY

THE AXIS OF THE WAVE AS MOVED THROUGH THE MAJORITY OF THE FORECAST
AREA...WITH BUILDING NORTHWEST FLOW AND ASSOCIATED RIDGE OF HIGH
PRESSURE. SOME LINGERING SHOWER ACTIVITY MAY REMAIN OVER THE HIGHER
ELEVATIONS INTO THE EVENING HOURS...BUT MOST ACTIVITY WILL END
DURING THE EARLY EVENING HOURS.

A DRY DAY IS EXPECTED ON TUESDAY IN RESPONSE TO THE RIDGE OF HIGH
PRESSURE. SOME AREAS OF PATCHY FOG WILL BE POSSIBLE ACROSS THE WEST
WHERE PRECIPITATION REMAINED PRESENT THIS MORNING. OTHERWISE...COOL
TEMPERATURES WILL AGAIN BE FOUND...THOUGH THEY WILL BE SLIGHTLY
WARMER COMPARED TO WHAT OCCURRED TODAY OVER THE AREA. SOME GUSTY
WIND WILL BE POSSIBLE ACROSS THE WIND CORRIDOR BETWEEN KRKS AND KCPR
DURING THE AFTERNOON HOURS.

.LONG TERM...TUESDAY NIGHT THROUGH MONDAY

THE GLOBAL MODELS ARE STILL IN DECENT AGREEMENT ON THE EVOLUTION OF
THE LONG WAVE PATTERN TO MORE OF AN AMPLIFIED FLOW AS THE CURRENT
TROUGH PASSING OVERHEAD DIGS TO OUR EAST AND A STORM SYSTEM OVER THE
GULF OF ALASKA DIGS INTO AN OPEN WAVE ALONG THE WEST COAST...MOVING
ASHORE AND AFFECTING OUR FORECAST AREA LATE THIS WEEKEND. THE GFS
HAS SPED UP A BIT WITH THE COLD FRONT ASSOCIATED WITH THIS NEXT
STORM...NOW MOVING IT INTO THE REGION EARLY ON SATURDAY INSTEAD OF
LATE ON SUNDAY...QUITE A CHANGE IN 24 HOURS. THE EUROPEAN IS
ACTUALLY DIGGING THE TROUGH A LITTLE MORE AND BRINGING A CLOSED
UPPER LOW RIGHT OVER WYOMING BY SATURDAY NIGHT...ALSO MUCH FASTER
THAN PREVIOUS RUNS. SO...NOT MUCH CHANGE WAS MADE TO THE PREVIOUS
FORECAST BUT SOME POPS WERE INTRODUCED A LITTLE BIT EARLIER...THERE
ALSO MAY BE SOME ROOM TO DROP HIGH TEMPERATURES ON SATURDAY IF THIS
QUICKER PROGRESSION TAKES PLACE.

THE FIRST FEW PERIODS STILL LOOK RATHER WARM FOR THIS TIME OF YEAR
AS THE RIDGE AMPLIFIES IN RESPONSE TO THE STORMS TO OUR EAST AND
WEST. THERE WILL BE SOME WINDY PERIODS...ESPECIALLY ON THURSDAY AND
FRIDAY AS THIS TRANSITION TAKES PLACE.

FOR HALLOWEEN ON FRIDAY...IT STILL LOOKS WARM...IN THE 60S ACROSS
THE LOWER ELEVATIONS...NEAR 70 IN THE BIGHORN BASIN AND ALONG THE
I25 CORRIDOR...BUT BREEZY FOR MUCH OF THE AREA. STRONGEST WINDS WILL
STILL BE BETWEEN ROCK SPRINGS AND CASPER AROUND TRICK OR TREAT TIME
WITH SOUTH/SOUTHWEST WINDS OF 15 TO 25 MPH EXPECTED....THE
OCCASIONAL GUST TO 40 MPH IS POSSIBLE IN FAVORED AREAS. GIVEN THE
FASTER TIMING OF THE RECENT MODEL RUNS...IT LOOKS LIKE THE RIDGE
AXIS WILL BE EAST OF THE AREA INSTEAD OF OVER THE AREA...SO THIS
WILL ENCOURAGE SOUTHWEST FLOW JUST ABOUT EVERYWHERE...IT ALSO LOOKS
LIKE THE LEE TROUGH IS DIGGING A LITTLE MORE WHICH WILL INCREASE THE
SURFACE PRESSURE GRADIENT...AND THEREFORE THE WIND SPEEDS...SO HOLD
ON TO YOUR WITCH HATS!

&&

.AVIATION.../00Z DISCUSSION/

A BUILDING RIDGE OF HIGH PRESSURE WILL LEAVE GENERALLY VFR
CONDITIONS ACROSS THE AREA...THOUGH A FEW SHOWERS WILL BE POSSIBLE
ACROSS THE NORTHERN MOUNTAINS THROUGH 09Z THIS EVENING. HAVE
INCLUDED VCFG AT KJAC AFTER 10Z...THOUGH CONFIDENCE IN ITS
DEVELOPMENT IS STILL A BIT LOW. OTHERWISE...THE ONLY OTHER MAIN
CONCERN IS THE POTENTIAL FOR RETURNING GUSTY WIND AFTER 18Z
TUESDAY...MAINLY IMPACTING THE WIND CORRIDOR BETWEEN KRKS AND
KCPR.

&&

.FIRE WEATHER...

BUILDING HIGH PRESSURE OVER THE AREA WILL BRING DRIER CONDITIONS
ACROSS THE STATE...WITH LOWERING DAYTIME HUMIDITY. SOME GUSTY WIND
WILL BE FOUND BETWEEN ROCK SPRINGS AND CASPER...WHICH MAY SLIGHTLY
ELEVATE FIRE BEHAVIOR...THOUGH TEMPERATURES WILL REMAIN COOL.
TEMPERATURES WILL CONTINUE TO WARM THROUGH THE REMAINDER OF THE WORK
WEEK. A WEAK WAVE WILL BRING THE POTENTIAL FOR SOME SHOWER ACTIVITY
DURING THE MIDDLE PORTION OF THE WEEK...WITH OTHERWISE DRY
CONDITIONS EXPECTED.

&&

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

$$

SHORT TERM...BRANHAM
LONG TERM...ALLEN
AVIATION...BRANHAM
FIRE WEATHER...BRANHAM





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