Area Forecast Discussion
Issued by NWS Riverton, WY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KRIW 180856
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
256 AM MDT THU SEP 18 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

THE RIDGE OF HIGH PRESSURE CONTINUES TO MOVE EAST THROUGH THE
FORECAST AREA TODAY. EXPECT SOME CONTINUED SHOWER AND THUNDERSTORM
ACTIVITY THIS MORNING...ESPECIALLY ACROSS THE WESTERN THIRD OF THE
FORECAST AREA. THE RIDGE WILL ALLOW TEMPERATURES TO CONTINUE THEIR
WARMING TREND TODAY...WITH SEVERAL STATIONS SEEING THE POTENTIAL TO
EXPERIENCE RECORD BREAKING HIGH TEMPERATURES. ADDITIONALLY...THE
PERSISTENT AREA OF HIGH PRESSURE WILL RESULT IN CRITICAL FIRE
WEATHER BEHAVIOR ACROSS PORTIONS OF NATRONA COUNTY THIS AFTERNOON.
DETAILS CAN BE FOUND IN THE FIRE WEATHER PRODUCTS.

THE AXIS OF THE RIDGE WILL BE EAST OF THE FORECAST AREA BY THIS
EVENING...WITH SOUTHWEST FLOW BUILDING OVER THE AREA. DECENT SLUGS
OF MOISTURE WILL CONTINUE TO MOVE THROUGH WESTERN WYOMING...WITH
SHOWERS AND THUNDERSTORMS CONTINUING. GUSTY WIND AND SMALL HAIL WILL
BE POSSIBLE WITH STORMS INTO THE EVENING HOURS.

WEST TO SOUTHWEST FLOW REMAINS OVER THE AREA BY FRIDAY
AFTERNOON...WITH A WEAKER PUSH OF MOISTURE. THE CHANGE IN WEATHER
PATTERN WILL ALLOW SOME COOLER TEMPERATURES TO BE PRESENT ACROSS THE
AREA INTO THE WEEKEND. WIDELY SCATTERED TO SCATTERED SHOWERS AND
THUNDERSTORMS ARE STILL ANTICIPATED...MAINLY ACROSS THE SOUTHEASTERN
HALF OF THE FORECAST AREA. A RETURN OF HIGH PRESSURE IS ANTICIPATED
BY SATURDAY MORNING...WITH SHOWER ACTIVITY TAPERING OFF. DRY
GENERALLY DRY CONDITIONS THEN ANTICIPATED THROUGH SATURDAY EVENING.

.LONG TERM...SUNDAY THROUGH THURSDAY

A CUT OFF UPPER LOW OVER THE GREAT BASIN SUNDAY WILL SEND SOME
CONVECTION INTO THE WEST/SOUTHWEST SUNDAY AFTERNOON. GLOBAL MODELS
SHOW THIS UPPER LOW PUSHING NORTHEAST INTO THE COWBOY STATE LATE
SUNDAY NIGHT/MONDAY MORNING. THIS WILL RESULT IN INCREASING CHANCES
OF CONVECTION SUNDAY NIGHT AND MONDAY WITH AN EMPHASIS ACROSS THE
SOUTHWEST AND SOUTH...BUT THE ENTIRE AREA WILL HAVE A SHOT AT SOME
PRECIPITATION. THIS SYSTEM IS A WARM ONE...SO ANY SNOW WILL BE
CONFINED TO 11+ KFT MSL. THE 00Z ECMWF AND GEM ARE SLOWER IN KICKING
THIS UPPER LOW OUT OF THE AREA THAN THE 00Z GFS...WITH SOME
LINGERING CONVECTION ON TUESDAY. HAVE ADDED POPS...MAINLY
SLIGHT...ACROSS MUCH OF THE AREA TUESDAY FOR THE TREND OF THE
SLOWER SOLUTIONS OF THE ECMWF AND GEM. WEDNESDAY SHOULD BE DRY AND
WARM AHEAD OF A TROUGH THAT COULD IMPACT THE AREA THURSDAY AND/OR
FRIDAY. GLOBAL MODELS AND THEIR RESPECTIVE ENSEMBLE MEMBERS HAVE
CONSIDERABLE VARIABILITY IN TIMING/STRENGTH OF THIS TROUGH LATE
NEXT WEEK INTO NEXT WEEKEND. THE OPERATIONAL GFS IS THE QUICKEST
PUSHING A STRONG COLD FRONT THROUGH THE AREA LATE WEDNESDAY NIGHT
INTO THE DAY THURSDAY...WHILE THE ECMWF IS SLOWER WITH A
SPLITTING TROUGH WITH FRONTAL PASSAGE ON FRIDAY.

TEMPERATURES THROUGH MUCH OF THE EXTENDED WILL BE ABOVE TO WELL
ABOVE AVERAGE.

&&

.AVIATION.../12Z ISSUANCE/

ISOLATED SHOWERS OR STORMS WILL MOVE THROUGH NW WY THROUGH 12Z. A
WEATHER SYSTEM WILL BE MOVING CLOSER TO THE REGION TODAY AND TONIGHT.
SCATTERED SHOWERS AND STORMS WILL DEVELOP AFTER 18Z OVER WESTERN WY
AND CONTINUE THROUGH 12Z FRIDAY. OUTFLOW WIND GUSTS TO 35 KNOTS WILL
BE LIKELY WITH STORMS. EAST OF THE CONTINENTAL DIVIDE SHOWERS AND
STORMS WILL BE ISOLATED TODAY AND TONIGHT. AFTER 06Z FRIDAY SHOWERS
WILL BEGIN TO INCREASE IN COVERAGE IN CENTRAL WY ALONG WITH ISOLATED
THUNDERSTORMS. VFR CONDITIONS WILL OCCUR THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

HIGH PRESSURE WILL BRING ANOTHER WARM DAY ACROSS WESTERN AND CENTRAL
WYOMING. SOME AREAS WILL SEE SOME GUSTY WIND DEVELOPING DURING THE
AFTERNOON HOURS...ESPECIALLY OVER SWEETWATER AND NATRONA COUNTIES.
RELATIVE HUMIDITY WILL DECREASE TODAY...ESPECIALLY OVER NATRONA
COUNTY. THE COMBINATION OF CRITICALLY DRY FUELS...GUSTY WIND...AND
LOW HUMIDITY HAS RESULTED IN THE ISSUANCE OF A RED FLAG WARNING THIS
AFTERNOON FOR THE LOWER ELEVATIONS OF NATRONA COUNTY. THE REMAINDER
OF THE AREA WILL EITHER SEE WIND OR HUMIDITY WHICH IS NOT
CRITICAL...OR FUELS HAVE BEEN DETERMINED TO BE TOO MOIST TO BE
CONCERNED WITH EXPLOSIVE FIRE GROWTH. RED FLAG CONDITIONS COULD
TAPER OFF QUICKLY DURING THE LATE AFTERNOON HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TODAY TO 8 PM MDT THIS EVENING WYZ280.

&&

$$

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.