Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 170523
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1123 PM MDT THU OCT 16 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY

SAT IMAGERY SHOWS MODEST RIDGE WEST WITH A COUPLE OF FLEETING WEAK
UPR WAVES UPSTREAM MOVING THIS WAY. THE SFC SHOWS INCREASING HIGH
PRESSURE ACROSS THE NRN 2/3RDS OF THE FA BEHIND A SLOWLY EXITING DRY
COLD FRONT. WINDS HAVE DECREASED NEAR SFC AS THE PRESSURE GOES UP
AND THE P GRAD GOES DOWN. THESE WINDS WILL REMAIN ON THE LOW SIDE
THRU THE FCST PERIOD. THE ONLY REAL EFFECT THE UPR WAVES WILL HAVE
ON THE FCST AREA AS THEY MOVE THRU THE UPR FLOW OVER THE NEXT DAY
WILL BE TO BRING SOME INCREASE IN MID/UPR CLOUDINESS PERIODICALLY.
FIRST WAVE IS LOCATED ACROSS CNTRL/ERN ID ORIENTED N/S AS IS ALREADY
PUSHING MID/UPR CLOUDS OUT AHEAD OF IT ACROSS THE WRN FA. THE SECOND
WAVE IS JUST NOW COMING INTO WCNTRL CALIFORNIA...WITH AN ETA NEAR
WRN WY BY MID-DAY FRIDAY. FINALLY...UPR LVLS WILL WARM A FEW DEGREES
OVR THE NEXT 24 TO 36 HRS AS WILL THE SFC...BUT NOTHING DRAMATIC
WITH ONLY WEAK RIDGING OCCURRING BETWEEN THE SHORTWAVES...CLOUDS IN
AND OUT...AND LOWERING SUN ANGLES.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

MILD LATE OCTOBER WEATHER TO CONTINUE THROUGH AT LEAST MONDAY BEFORE
A WEAKENING SPLITTING PIECE OF ENERGY WORKS TOWARD THE AREA TUESDAY
INTO WEDNESDAY. HEIGHTS ARE EXPECTED TO REBUILD OVER THE AREA
THURSDAY AS THIS SYSTEM WEAKENS...MOVES EAST AND SHEARS APART. ECMWF
HAS BEEN SUPERIOR SINCE I WORKED MY STRING OF MIDS LAST WEEK AND
WILL LEAN ON IT AGAIN TODAY BUT DIFFERENCES ARE NOT NEARLY AS LARGE
AS THEY WERE AT TIMES LAST WEEK. FIRST SYSTEM TO AFFECT US THAT GETS
KICKED OUT FROM THE GULF OF ALASKA LOW WILL WEAKEN AS IT HEADS INTO
THE MEAN RIDGE WITH MAINLY JUST HIGH CLOUDS TO DEAL WITH FRIDAY
NIGHT AND SATURDAY. RIDGE AXIS STRENGTHENS AGAIN AS THIS SYSTEM
SHEARS APART FOR A MOSTLY CLEAR AND DRY PERIOD THROUGH MONDAY. NEXT
APPROACHING SHORTWAVE WHICH IS THE REMNANT GULF OF ALASKA LOW THAT
GETS KICKED OUT AS A STRONG TROUGH MOVES OFF OF ERN ASIA AND RACES
ACROSS THE PACIFIC...EVENTUALLY REPLACES THE CURRENT GULF OF ALASKA
LOW BY THE MIDDLE OF NEXT WEEK. AS THE CURRENT UPPER LOW GETS KICKED
OUT...IT WEAKENS AND MOVES ACROSS US TUESDAY INTO WEDNESDAY. NEW GFS
AND ECMWF HAVE TRENDED WEAKER WITH MORE SHEARING ACTION WITH THIS
SYSTEM AS IT BUMPS INTO THE RIDGE OVER THE PLAINS SO NOT LOOKING AS
GOOD AS EARLIER RUNS FOR ANY WIDESPREAD SHOWERS. NOT A LOT OF COLD
AIR EITHER EXPECTED WITH THIS SYSTEM AS IT WEAKENS RAPIDLY WITH H7
TEMPS GENERALLY ABOVE 0C. SNOW LEVELS WILL REMAIN IN THE MOUNTAINS
AND GENERALLY ABOVE 9000 TO 10000 FEET. OTHERWISE...NORMAL TO ABOVE
NORMAL TEMPERATURES CONTINUE THROUGH MONDAY WITH 60S AND SOME LOWER
70S EAST OF THE DIVIDE WITH 50S AND 60S WEST. MONDAY LOOKS TO BE THE
WARMEST DAY ALTHOUGH DEPENDING ON THE TIMING OF OUR APPROACHING
SYSTEM...TUESDAY COULD BE JUST AS WARM EAST OF THE DIVIDE. A LITTLE
COOLER WEDNESDAY WITH CLOUDS AND POSSIBLE SHOWERS IN THE AREA WITH
TEMPS REBOUNDING ON THURSDAY. OVERALL...ABNORMALLY MILD OCTOBER
WEATHER TO CONTINUE FOR THE FORESEEABLE FUTURE WITH ONLY ONE SHOT
FOR SHOWERS WITH THE MIDWEEK SYSTEM.

&&

.AVIATION.../06Z ISSUANCE/

CONDITIONS WILL BE VFR AT ALL TERMINALS THROUGH THE FORECAST PERIOD.
SHORTWAVE THAT BROUGHT MID/HIGH CLOUD COVER THURSDAY EVENING NOW
MOVING EAST OF THE FORECAST AREA. ANOTHER ROUND OF MID/HIGH CLOUDS
WILL ARRIVE LATE FRIDAY AFTERNOON FROM THE WEST-SOUTHWEST. SURFACE
WINDS WILL BE LESS THAN 10KTS AT ALL TERMINALS.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW...AND WILL REMAIN RELATIVELY LOW THROUGH THE
WEEKEND ACROSS THE ENTIRE FORECAST AREA. TODAY AND FRIDAY...COOLER
TEMPERATURES WITH LESS WIND WILL CHARACTERIZE THE WEATHER ACROSS THE
REGION AS A RIDGE OF HIGH PRESSURE BUILDS IN BEHIND A SLOWLY EXITING
COLD FRONT. THEN...A BUILDING RIDGE WILL BRING SOME WARMER
TEMPERATURES FOR THE WEEKEND...WITH BREEZY CONDITIONS ACROSS THE
SOUTHERN DISPATCH ZONES ON SATURDAY. HOWEVER MOISTURE WILL ALSO BE
ON THE INCREASE...KEEPING CLOUDS IN THE SKY AND RELATIVE HUMIDITY
VALUES WELL ABOVE CRITICAL LEVELS.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...SKRBAC
AVIATION...CNJ
FIRE WEATHER...BRAUN












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