National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS65 KRIW 100551
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1150 PM MDT WED JUL 9 2014

.SHORT TERM...TONIGHT THROUGH THURSDAY (ISSUED AT 232 PM MDT)

A RIDGE OF HIGH PRESSURE IS FLATTENING THIS AFTERNOON...IN
RESPONSE TO AN UPPER LEVEL TROUGH OVER WESTERN CANADA. A SHORTWAVE
MOVING ACROSS THE NORTHERN ROCKIES IS AIDING WITH THIS...AS WELL
AS MOVING THE RIDGE FURTHER EAST. ISOLATED THUNDERSTORMS MAY
DEVELOP AHEAD OF THIS TROUGH OVER NORTHWEST PORTIONS LATE THIS
AFTERNOON.

ISOLATED SHOWERS AND THUNDERSTORMS WILL WEAKEN AND SUBSIDE
TONIGHT...AS THE SUN SETS. ANY LINGERING CONVECTION WILL BE
CONFINED TO WESTERN PORTIONS OF THE FORECAST AREA TONIGHT. THIS
AREA WILL BE THE FOCUS THURSDAY MORNING...AS THE NEXT SURGE OF
MOISTURE BEGINS TO SPREAD ACROSS THE REST OF THE STATE. SHOWERS
AND THUNDERSTORMS WILL BEGIN TO FORM FROM WEST TO EAST...WITH
AREAS EAST OF THE DIVIDE BEING IMPACTED BY MID- AFTERNOON. FLASH
FLOODING WILL BE THE MAIN THREAT WITH THESE STORMS...AS THE
ATMOSPHERE WILL HAVE HIGH PW VALUES AND WEAK STEERING FLOW ALOFT.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY NIGHT

MUCH OF THE LONG RANGE PERIOD FOR THE MOST PART IS SIMILAR TO THE
INSTRUCTIONS YOU WOULD SEE ON A SHAMPOO BOTTLE. IN OTHER WORDS
WASH...RINSE... REPEAT. A COLD FRONT WILL CONTINUE WORKING ACROSS
THE AREA THROUGH THURSDAY EVENING...SO CONVECTION IS LIKELY TO
CONTINUE INTO THE EVENING HOURS BEFORE SUBSIDING BUT NOT ENDING
BEFORE SUNRISE. FRIDAY LOOKS LIKE A SIMILAR DAY TO THURSDAY WITH
PRECIPITABLE WATERS EXPECTED TO BE ABOVE 1 INCH FOR MANY AREAS
ONCE AGAIN. THERE WILL ALSO BE A DECENT AMOUNT OF SHEAR PRESENT...SO
SOME STORMS COULD BECOME STRONG. THE MAIN THREAT STILL LOOKS TO BE
FLASH FLOODING WITH THE AMPLE MOISTURE AND EXPECTED SLOWER
MOVEMENT OF THE STORMS. BY SATURDAY...LESS COVERAGE OF SHOWERS AND
THUNDERSTORMS IS EXPECTED...AS THE DEEPEST LOW AND MID LEVEL
MOISTURE WILL GET SHOVED TO THE SOUTH AND EAST OF THE COUNTY
WARNING AREA. HOWEVER...WITH ANOTHER SHORTWAVE MOVING ACROSS THE
AREA WE HAVE KEPT SOME CHANCE OF PRECIPITATION IN THE FORECAST.
TEMPERATURES SHOULD AVERAGE NEAR NORMAL EAST OF THE DIVIDE AND A
BIT ABOVE NORMAL WEST OF THE DIVIDE.

AT THIS POINT SUNDAY LOOKS TO BE FAIRLY SIMILAR TO SATURDAY IN
REGARDS TO COVERAGE OF PRECIPITATION AND TEMPERATURES. IT CERTAINLY
WILL NOT RAIN ALL THE TIME...BUT THERE WILL BE A CHANCE OF SOMETHING
FOR JUST ABOUT EVERYONE. BY MONDAY...DEEPER MOISTURE WILL BEGIN
TO RETURN TO THE AREA FROM THE SOUTHEAST AHEAD OF A BACKDOOR
FRONTAL BOUNDARY THAT WILL BE SLIDING TOWARD THE AREA OUT OF THE
DAKOTAS. CONTINUITY TEMPERATURES ARE WELL BELOW THE MOS
NUMBERS...ESPECIALLY FOR TUESDAY AND WEDNESDAY. A LOT DEPENDS ON
HOW FAR SOUTH THE FRONT MAKES IT. FOR NOW...WE STUCK WITH THE
COOLER TEMPERATURES SINCE MOS TENDS TO FACTOR IN CLIMATOLOGY IN
THE LONGER TERM. THE CHANCE OF DAILY...MAINLY DIURNAL CONVECTION...WILL
CONTINUE INTO NEXT WEEK AS WELL.

&&

.AVIATION.../06Z ISSUANCE/

A PLUME OF SUB-TROPICAL MOISTURE WILL CONTINUE TO ROTATE ACROSS THE
AREA THROUGH THURSDAY...AND THEN BE SUPPRESSED FURTHER SOUTH
THURSDAY NIGHT...MAINLY VCNTY AND SOUTH OF A KRKS-KCPR LINE BY 12Z
FRIDAY.  ISOLATED SHOWERS AND THUNDERSTORMS WILL CONTINUE OVERNIGHT
ACROSS NORTHERN AND WESTERN WYOMING.   WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL BLOSSOM OVER MOST OF THE REGION THURSDAY
AFTERNOON THROUGH EARLY EVENING WITH OCNL HIGHER MTN OBSCURATIONS
AND POSSIBLE BRIEF MVFR CONDITIONS AT ALL TERMINALS.  THIS ACTIVITY
WILL SUBSIDE AFTER SUNSET WITH ISOLATED SHOWERS AND THUNDERSTORMS
CONFINED TO VCNTY KRKS-KCPR AND SOUTH AFTER 06Z FRIDAY.



&&

.FIRE WEATHER...

ZONAL FLOW...IN ADDITION TO A WEAK DISTURBANCE OVER THE AREA WILL
PERMIT ADDITIONAL AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY ON
THURSDAY AND FRIDAY. GUSTY AND ERRATIC WIND WITH CLOUD TO GROUND
LIGHTNING...AND LOCALIZED FLASH FLOODING WILL BE THE PRIMARY
THREATS WITH ACTIVITY. THE CHANGING IN SYSTEMS WILL ALLOW
TEMPERATURES TO COOL SLIGHTLY THROUGH THE PERIOD...WITH GENERALLY
LIGHT SURFACE WIND ANTICIPATED.

&&

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

$$

SHORT TERM...LAVOIE
LONG TERM...HATTINGS
AVIATION...AEM
FIRE WEATHER...LAVOIE