Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 310353
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
953 PM MDT THU JUL 30 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST WITH A
GRADUAL WARM UP EXPECTED. RELATIVE HUMIDITY WILL REMAIN VERY DRY.
CURRENTLY...RH READINGS ARE IN THE SINGLE DIGITS IN SOUTHWEST
WYOMING WHERE DEW POINT ARE LOWEST. OVER OUR CWA BORDER...IN
EXTREME SOUTHWEST UTAH...EVW HAS A DEW POINT OF ONLY 6 WHERE THE
RH IS ONLY 6 PERCENT. THESE LOWER DEW POINTS WILL CONTINUE TO
STREAM IN FROM THE WEST AND SOUTHWEST KEEPING THE AIRMASS DRY WITH
UPPER SINGLE DIGITS EXPECTED TO SPREAD NORTH INTO THE BIG HORN
BASIN FRIDAY AFTERNOON. IN SPITE OF THE DRY CONDITIONS...WINDS
WILL REMAIN RATHER LIGHT SO FIRE DANGER WILL HELD BE IN CHECK.
TEMPERATURES WILL BEGIN TO FLIRT WITH THE 90 DEGREE MARK FRIDAY
AFTERNOON OVER SOME OF THE LOWER ELEVATIONS EAST OF THE DIVIDE
FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

DRY AND VERY WARM START TO THE PERIOD WITH RIDGE AXIS CENTERED FROM
UPPER HIGH AROUND NM NWWD INTO THE NRN GREAT BASIN. MORE OF THE
MODELS ARE NOW SHOWING A DEVELOPING ELY WAVE THAT FORMS OR MOVES
NWWD INTO AZ ON SATURDAY AND THEN LIFT NWD AND THEN NE ACROSS US
SUNDAY NIGHT AND MONDAY WITH DECENT MID LEVEL MOISTURE AND LIMITED
LOW LEVEL MOISTURE. ENOUGH FOR SHOWERS AND THUNDERSTORMS THOUGH WITH
GUSTY WIND AND LIGHTNING. A FEW STORMS ARE STILL POSSIBLE IN THE NRN
MOUNTAINS LATE SATURDAY BUT THEY WILL BE VERY ISOLATED IF THEY
OCCUR. ON SUNDAY...SHOULD SEE STORMS FORMING OFF THE UINTAS AND
MOVING NE LATE IN THE DAY/EVENING ACROSS SWEETWATER
COUNTY...ESPECIALLY SRN AND ERN AREAS. STRONG OUTFLOW WINDS AND
LIGHTNING WILL BE THE BIGGEST CONCERN WITH THESE. A FEW ARE STILL
POSSIBLE IN THE NRN MTNS. COULD SEE A FEW OVERNIGHT SHOWERS/TSTMS
DRIFTING N AND NE INTO THE CENTRAL ZONES OVERNIGHT SUNDAY WITH A
BETTER SHOT OF AT LEAST ISOLATED TO WIDELY SCT STORMS ON
MONDAY...SCT IN THE MTNS. MAIN CONCERN WILL STILL BE STRONG AND
GUSTY WIND AND LIGHTNING. SOUTH WILL DRY OUT AND EVENTUALLY MOST OF
THE NRN TUESDAY INTO WEDNESDAY AS RIDGE REBUILDS OVER THE 4-CORNERS
AND UPPER TROUGH FORMS OFF THE WEST COAST...ESPECIALLY PACNW. THIS
PATTERN IS VERY FAVORABLE FOR AN EVEN BETTER SURGE OF MONSOONAL
MOISTURE BEGINNING AS EARLY AS NEXT THURSDAY AND BEYOND THE MEDIUM
RANGE PERIOD. AT LEAST THAT`S HOW THE GFS SEES IT. THE ECMWF HAS A
MORE SUPPRESSED UPPER HIGH NEAR THE MEXICAN BORDER WITH A SW FLOW
OVER THE AREA WITH EMBEDDED DISTURBANCES. LEAN TOWARDS THE GFS AS
THIS IS THE CLIMATOLOGICAL TIME FOR A 4-CORNERS MONSOONAL HIGH. BOTH
STILL HAVE A CHANCE OF TSTMS ON THURSDAY SO THE MAIN CHALLENGE WITH
TIME WILL BE TO SEE THE MODEL TREND AND HIT THE POPS HARDER IF IT
LOOKS LIKE A MOIST MULTI-DAY SURGE WILL HEAD NWD FOR THE SECOND HALF
OF NEXT WEEK.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH 06Z SATURDAY. THE WIND WILL BE
LIGHT AND VARIABLE AND FOCUS ON TERRAIN INFLUENCES. A FEW FAIR
WEATHER CUMULUS MAY DEVELOP OVER A FEW LOCATIONS. ISOLATED SHOWERS
MAY DEVELOP AFTER 21Z ACROSS EASTERN WYOMING BUT WILL STAY AWAY FROM
TAF SITES.

&&

.FIRE WEATHER...

BUILDING HIGH PRESSURE WILL CONTINUE MAINLY CLEAR...WARMING...AND
DRY CONDITIONS THROUGH THE END OF THE WEEK. GENERALLY LIGHT WINDS
ARE EXPECTED THROUGH THE WEEKEND...WITH ONLY A FEW LIGHT BREEZES
POSSIBLE FRIDAY AFTERNOON/EVENING ACROSS CENTRAL WYOMING. MINIMUM
RH VALUES ARE EXPECTED TO REMAIN IN THE SINGLE DIGITS TO LOW TEENS
THROUGH THE WEEKEND ACROSS THE SOUTH AND AREAS EAST OF THE
DIVIDE...WITH UPPER TEENS TO 20S ACROSS THE WEST. RELATIVE
HUMIDITY WILL HAVE A HARD TIME RECOVERING OVERNIGHT...ESPECIALLY
AT MID SLOPE WHERE RHS MAY NOT RISE OUT OF THE MID
20S...ESPECIALLY IN THE CENTRAL WYOMING RANGES. DRY CONDITIONS ARE
EXPECTED THROUGH AT LEAST SATURDAY. ISOLATED THUNDERSTORM CHANCES
WILL RETURN SUNDAY INTO EARLY NEXT WEEK...MAINLY ACROSS NORTHERN
AND WESTERN PORTIONS.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...HATTINGS
FIRE WEATHER...LIPSON



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