Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 101722
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1122 AM MDT THU JUL 10 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT (ISSUED AT 326 AM)

A SWATH OF CLOUD COVER CONTINUES TO MOVE INTO WESTERN WYOMING THIS
MORNING...WITH A FEW SHOWERS AND THUNDERSTORMS LINGERING WEST OF THE
CONTINENTAL DIVIDE. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
WEAKEN OVERNIGHT...THOUGH COVERAGE WILL NOT COMPLETELY DISSIPATE. A
COLD FRONT WILL PUSH THROUGH NORTHERN WYOMING THIS MORNING AND
AFTERNOON...HELPING TO INITIATE SOME ADDITIONAL SHOWERS AND
THUNDERSTORMS. STORMS MAY CONTAIN GUSTY WIND WITH MODELS
DEMONSTRATING THE BEST AREA OF INSTABILITY BEING GENERALLY EAST OF
THE FORECAST AREA.

SHOWER ACTIVITY WILL AGAIN WEAKEN DURING THE OVERNIGHT HOURS
TONIGHT. A RETURN OF SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED ON
FRIDAY. MODELS HAVE DECREASED THE ANTICIPATED COVERAGE OF STRONGER
STORMS ON FRIDAY...WITH SOME STRONGER STORMS STILL POSSIBLE DURING
THE LATE EVENING HOURS. THESE STORMS MAY PRODUCE GUSTY WIND AND
SMALL HAIL.

A WEAK RIDGE OF HIGH PRESSURE WILL ATTEMPT TO DEVELOP WEST OF THE
FORECAST AREA LATE FRIDAY NIGHT...AND WILL CONTINUE TO AMPLIFY
DURING THE OVERNIGHT HOURS. AS THIS RIDGE STRENGTHEN...EXPECT
SHOWERS AND THUNDERSTORMS TO WEAKEN ACROSS THE AREA...WITH LESSENED
COVERAGE EXPECTED ON SATURDAY...THOUGH SOME ISOLATED ACTIVITY WILL
REMAIN POSSIBLE.

OVERALL...TEMPERATURES WILL DECREASE THROUGH THE WORK WEEK...WITH
SOME WARMING ANTICIPATED SATURDAY OVER WESTERN WYOMING. GENERALLY
LIGHT WIND ANTICIPATED OUTSIDE OF THUNDERSTORM ACTIVITY.

LONG TERM...SUNDAY THROUGH THURSDAY

AT THE BEGINNING OF THE PERIOD...A SUBTROPICAL RIDGE WILL BE ACROSS
THE GREAT BASIN/SOUTHERN ROCKIES...AND A VERY STRONG UPPER LOW...FOR
JULY...LOCATED OVER NORTHEAST MANITOBA. THERE WILL ALSO BE A WEAK
SHORTWAVE OFF THE OREGON COAST. GLOBAL MODELS ARE IN GOOD
AGREEMENT WITH THE UPPER LOW OVER MANITOBA PUSHING SOUTH INTO THE
UPPER MIDWEST SUNDAY NIGHT/MONDAY. THIS WILL LIKELY SEND A STRONG
COLD FRONT FOR JULY THROUGH THE ENTIRE FORECAST AREA SUNDAY
NIGHT/MONDAY MORNING WHICH IS ABOUT 12-18 HOURS FASTER THAN
YESTERDAYS 00Z RUNS. THUS HAVE TRENDED COOLER FOR MONDAY. HAVE KEPT
POPS ACROSS THE ENTIRE AREA...BUT A FASTER ARRIVAL OF THE FRONT
COULD RESULT IN A GENERALLY COOL AND STABLE AIR MASS ACROSS THE
NORTH AND NORTHEAST...WITH THE BEST SHOT AT CONVECTION OVER
CENTRAL...WEST AND SOUTHWEST SECTIONS OF THE FORECAST AREA.

ON TUESDAY...A WEAK SHORTWAVE THAT WAS OFF THE OREGON COAST SUNDAY
IS PROGGED BY THE 00Z GFS AND ECMWF TO SLIDE SOUTHEAST ACROSS
EASTERN IDAHO/WESTERN WYOMING. IF TIMING AND LOCATION ARE CORRECT
THIS COULD RESULT IN A DECENT CHANCE OF CONVECTION ACROSS THE WEST
AND SOUTHWEST...WHILE A MORE STABLE AND COOL AIR MASS LINGERS EAST
OF THE DIVIDE.

BY WEDNESDAY AND THURSDAY...THE SYNOPTIC SETUP SHOULD HAVE RIDGING
OVER THE WEST COAST WITH A BROAD TROUGH OVER THE WESTERN 2/3 OF THE
CONUS...WITH A RELATIVELY DRY AND LIGHT NORTHERLY FLOW. HAVING SAID
THAT WILL KEEP SOME POPS...ESPECIALLY OVER THE SOUTHWEST AND/OR
MOUNTAINS.

TEMPERATURES WILL GENERALLY BELOW AVERAGE EAST OF THE DIVIDE THROUGH
MUCH OF THE EXTENDED...ESPECIALLY MONDAY AND TUESDAY WHEN HIGH TEMPS
ARE EXPECTED TO BE 8 TO 15 DEGREES BELOW NORMAL.

WEST OF THE DIVIDE WILL SEE ABOVE AVERAGE TEMPS SUNDAY...BUT MORE
SEASONAL TEMPERATURES FOR THE REMAINDER OF THE EXTENDED.

AVIATION.../18Z ISSUANCE/

CLOUDS HAVE COVERED MUCH OF WYOMING THIS MORNING. ISOLATED SHOWERS
HAVE BEEN CONFINED TO NORTHERN PORTIONS NEAR KCOD AND KWRL SINCE
12Z. HOWEVER...ADDITIONAL SHOWERS ARE BEGINNING TO FORM ACROSS THE
OTHER TAF SITES EXCEPT KRKS. EXPECT ISOLATED SHOWER ACTIVITY
THROUGH 05Z TONIGHT ACROSS THE AREA. ANY THUNDERSTORM ACTIVITY
WILL BE VERY ISOLATED. CLOUDS ARE EXPECTED TO REMAIN ACROSS THE
ARE OVERNIGHT...WITH A FEW BREAKS POSSIBLE DURING THE DAY FRIDAY.
WIDESPREAD THUNDERSTORM ACTIVITY IS STILL EXPECTED FRIDAY
AFTERNOON BETWEEN 20Z-06Z SATURDAY.

FIRE WEATHER...

PERIODS OF SHOWERS AND THUNDERSTORMS WILL BE FOUND BOTH THURSDAY AND
FRIDAY AFTERNOONS. SOME STORMS MAY PRODUCE GUSTY AND ERRATIC WIND
AND SMALL HAIL. STORMS WILL BE POSSIBLE ACROSS THE MAJORITY OF THE
FORECAST AREA DURING THESE AFTERNOONS. A BUILDING RIDGE OF HIGH
PRESSURE WILL IMPACT THE STATE OVER THE WEEKEND...BRINGING SOME
DRIER CONDITIONS. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL STILL REMAIN POSSIBLE...ESPECIALLY OVER THE NORTHERN HALF OF
THE FORECAST AREA. TEMPERATURES WILL GENERALLY COOL THROUGH THE
PERIOD...THOUGH SOME WARMING TEMPERATURES ARE NOTED ON SATURDAY OVER
SOUTHWESTERN WYOMING.

&&

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

$$

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






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