Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 300529
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1129 PM MDT TUE JUL 29 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

A DEEP PLUME OF MONSOONAL MOISTURE HAS MOVED OVER THE COUNTY WARNING
AREA. WITH SOME UPLIFT PROVIDED BY A MID LEVEL LOW MOVING ACROSS
UTAH MANY AREAS HAVE BEEN SEEING SHOWERY RAINS THROUGH THE MORNING
AND INTO THE AFTERNOON HOURS. THE GOOD PART ABOUT THIS IS THAT OVER
A MAJORITY OF THE AREA THERE HAS BEEN A MAINLY OVERCAST SKY THAT HAS
LIMITED INSTABILITY. AS A RESULT...MOST OF THE RAIN HAS BEEN OF THE
LIGHT TO MODERATE VARIETY WITH ONLY A FEW LIGHTNING STRIKES. THE
EXCEPTION SO FAR HAS BEEN SOUTHERN NATRONA COUNTY WHERE A STRONG
THUNDERSTORM DEVELOPED OVER CASPER MOUNTAIN. SOME CLEARING HAS BEEN
TRYING TO DEVELOP ACROSS SOUTHWESTERN WYOMING BUT ANY BREAKS SO FAR
HAVE CLOSED AS QUICKLY AS THEY HAVE FORMED. AS A RESULT...WE EXPECT
LITTLE SEVERE WEATHER. THE MAIN THREAT CONTINUES TO BE FLOODING WITH
PRECIPITABLE WATER VALUES RUNNING WELL OVER AN INCH. WITH THE
STRATIFORM NATURE OF THE RAIN...WE HAVE DECIDED AGAINST ISSUING A
FLOOD WATCH AT THIS POINT.

MODELS HAVE DIFFERING OPINIONS ON HOW FAST THE DEEPER MOISTURE GETS
MOVED OUT OF THE AREA. THE NAM HAS TRENDED SLOWER WITH KEEPING DEEP
MOISTURE OVER AREAS SOUTH OF THE OWL CREEK RANGE THROUGH TONIGHT.
MEANWHILE...THE GFS IS MUCH FASTER WITH PUSHING THE DEEP MOISTURE
OUT OF THE AREA BY AROUND 9Z. AT THIS POINT... CONTINUITY LOOKED
LIKE A DECENT SOLUTION. AS A RESULT WE KEPT THE HEAVY RAIN WORDING
THROUGH MIDNIGHT AND TAPERED THINGS OFF AFTER MIDNIGHT.

IT IS THE SAME PROBLEM FOR WEDNESDAY. THE NAM KEEPS MORE MOISTURE
OVER THE AREA...ALTHOUGH A DECENT AMOUNT LESS THAN TODAY. IT HAS
CONVECTION ACROSS MAINLY THE SOUTHWESTERN HALF OF THE COUNTY WARNING
AREA. THE GFS IS ONCE AGAIN THE DRIER MODEL IN BRINGING IN DRIER AIR
FURTHER SOUTH AND CONFINES ANY SHOWERS AND THUNDERSTORMS TO
NORTHWESTERN PORTIONS OF THE COUNTY WARNING AREA. ONCE AGAIN...WITH
THE UNCERTAINTY CONTINUITY LOOKED LIKE A REASONABLE COMPROMISE SO WE
MADE FEW CHANGES. WITH MORE SUNSHINE TOMORROW...TEMPERATURES SHOULD
BE WARMER THAN TODAY BY AROUND 5 TO 10 DEGREES BUT STILL BELOW
NORMAL FOR THE END OF JULY.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

WEAK OR DIRTY RIDGE OVER FORECAST AREA MUCH OF THE EXTENDED PERIOD.
THIS GENERALLY MEANS THERE WILL BE WIDELY SCATTERED AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS EACH DAY WITH JUST ENOUGH MOISTURE
AND LIFT FROM TERRAIN ACROSS WEST CENTRAL WYOMING. FACTORING IN
AMOUNT OF SUNSHINE AND TEMPERATURES ALOFT...DAYTIME HIGHS AND
OVERNIGHT LOWS SHOULD BE SIMILAR...OR NEAR NORMAL...FROM DAY TO DAY.

POSSIBLE INCREASE IN MONSOONAL MOISTURE SUNDAY AFTERNOON INTO EARLY
MONDAY...ESPECIALLY WEST OF THE DIVIDE PER MEDIUM RANGE MODELS.
COULD RESULT IN HIGHER POPS ACROSS THE WEST. SUNDAY NIGHT SHOULD BE
MILD. PATTERN THEN LOOKS UNSETTLED WITH THIS RIDGE FLATTENING AND
SERIES OF SHORTWAVES MOVING OVER WEST CENTRAL WYOMING.
THEREFORE...MONDAY NIGHT AND TUESDAY WILL BE COOLER WITH SCATTERED
SHOWERS AND THUNDERSTORMS FOR ALL AREAS.
&&

.AVIATION.../06Z ISSUANCE/

SCATTERED TO NUMEROUS SHOWERS WILL CONTINUE OVERNIGHT SOUTH OF A
KBPI TO KCPR LINE...WITH MUCH OF THE ACTIVITY OVER SOUTHERN LINCOLN
AND SWEETWATER COUNTIES. ALONG AND NORTH OF THIS AREA...WHERE RAIN
OCCURRED TUESDAY...SOME FOG WILL BE POSSIBLE DESPITE THE LINGERING
MID LEVEL CLOUDINESS...DUE TO VERY LOW TEMP/DEWPT DEPRESSIONS. THE
MAIN AREA OF SHOWERS OVER SWEETWATER COUNTY SHOULD DISSIPATE/EXIT
THE AREA BETWEEN 15Z AND 18Z. AT THE SAME TIME...ANY FOG SHOULD ALSO
LIFT. IN THE AFTERNOON...ISOLATED TO LOCALLY SCATTERED CONVECTION
WILL MAINLY OCCUR OVER THE WEST AND SOUTH. THE BEST INSTABILITY WILL
BE OVER THE FAR WEST AND WILL HAVE VCTS ONLY AT JAC TERMINAL...WITH
VCSH OVER THE REST OF THE TERMINALS WEST OF THE DIVIDE. ALTHOUGH
THERE COULD BE SOME ISOLATED CONVECTION EAST OF THE
DIVIDE...COVERAGE AND CONFIDENCE IS NOT HIGH ENOUGH TO HAVE VCSH.
DURING THE EVENING...CONVECTION SHOULD QUICKLY WANE.

FOR TERMINALS THE WORST CONDITIONS WILL OCCUR AT KRKS WITH
PERSISTENT MVFR/PERIODS OF IFR CONDITIONS EXPECTED THROUGH AROUND
15Z. OTHERWISE THE OTHER TAF SITES COULD SEE PERIODS OF MVFR/IFR
CONDITIONS MAINLY IN FOG THROUGH THE TIME FRAME. AFTER
15Z/16Z...MAINLY VFR CONDITIONS ARE EXPECTED WITH ONLY BRIEF
MVFR/IFR CONDITIONS POSSIBLE IN CONVECTION. WINDS WILL GENERALLY BE
EASTERLY IN MOST AREAS...BUT RELATIVELY LIGHT WITH THE EXCEPTION OF
BREEZY EAST WINDS ACROSS SWEETWATER COUNTY IMPACTING KRKS.

&&

.FIRE WEATHER...

A MORE SIGNIFICANT PUSH OF MOISTURE EXPECTED WILL CONTINUE INTO THIS
EVENING WITH WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY. SHOWERS
ARE ANTICIPATED TO CONTAIN HEAVY RAIN...HELPING TO ALLEVIATE SOME
FIRE WEATHER CONCERNS. WEDNESDAY WILL SEE A CONTINUATION OF SHOWER
ACTIVITY ALTHOUGH NOT AS HEAVY OR AS WIDESPREAD AS TODAY.
TEMPERATURES WILL BE WARMER BUT REMAIN BELOW NORMAL AND RELATIVE
HUMIDITY SHOULD REMAIN BELOW CRITICAL LEVELS FOR MOST AREAS.
&&

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

&&

$$

SHORT TERM...HATTINGS
LONG TERM...KPL
AVIATION...WM
FIRE WEATHER...HATTINGS








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