Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 232033
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
233 PM MDT TUE SEP 23 2014

.SHORT TERM...TONIGHT AND WEDNESDAY

UPPER LOW SPINNING ACROSS FAR SWRN SD/NWRN NE BORDER WITH WEAK
DISTURBANCE APPROACHING THE NW SUMS UP THE CURRENT WEATHER
PATTERN. MORNING FOG AND LOW CLOUDS DEVELOPED OUT WEST AS EXPECTED
WITH SOME OF THE FOG QUITE THICK THROUGH MID-MORNING AND LOW
CLOUDS LINGERING THROUGH THE AFTERNOON. WEAK INSTABILITY AND
RESIDUAL MOISTURE IS AIDING IN SOME WEAK CONVECTION IN AND NEAR
THE BIGHORN MOUNTAINS. FURTHER WEST...THE DAYTIME HEATING HAS BEEN
DELAYED WITH ALL THE FOG AND LOW CLOUDS SO ONLY WEAK CU ATTM. WILL
LEAVE IN ISOLD CONVECTION THROUGH EARLY EVENING BUT THAT`S ABOUT
IT. STILL LOOKS LIKE ANOTHER SHOT OF FOG/LOW CLOUDS WEDNESDAY MORNING
BUT NOT AS WIDESPREAD OR LONG LASTING AS TODAY. OTHERWISE...RIDGE
BUILDS IN THROUGH WED WITH A WARM AND DRY DAY IN STORE. TEMPERATURES
WILL WARM 5 TO 10 DEGREES MORE ON WEDNESDAY. HIGHS WILL GENERALLY
BE IN THE MID TO UPPER 80S EAST OF THE DIVIDE WITH UPPER 70S TO
LOWER 80S WEST OF THE DIVIDE AND MAINLY 60S AND 70S IN THE
MOUNTAINS.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

QUICKLY AMPLIFYING RIDGE WILL RETURNS TO THE FORECAST AREA...ALONG
WITH SUNNY/DRY SKIES THROUGH THURSDAY AND MOST OF FRIDAY. THIS WILL
BRING BACK ANOTHER PERIOD OF NEAR RECORD HEAT...ESPECIALLY ON
THURSDAY...CONTINUING OVER PORTIONS OF THE CWA THRU FRIDAY. ALL THIS
IS AHEAD OF ANOTHER LARGE AMPLIFYING TROF CURRENTLY DEVELOPING OVR
THE EPAC...EVENTUALLY RIDING INTO THE WRN CONUS BY WEEKS END.

BEGINNING OF FCST PERIOD THRU FRI...AMPLIFIED RIDGE ALOFT WITH H7
TEMPS RANGING FROM 13 TO 15 DEG C ON THUR...11 TO 13 ON FRI...AND
VIRTUALLY NO MOISTURE WILL KEEP SKIES MOSTLY CLEAR WITH NEAR
RECORD/RECORD WARM TO HOT CONDITIONS AT THE SFC. ADDITIONALLY THERE
WILL BE NO CHC FOR PRECIP UNTIL POSSIBLY LATE FRIDAY WITH THE
APPROACH OF SOME MODEST MID LVL MOISTURE AND PERHAPS A WEAK UPR
WAVE. EVEN THEN...IT WILL ALSO TAKE THE HIGHER TERRAIN OF THE
MOUNTAINS IN COMBINATION WITH THESE MODEST PARAMETERS TO SQUEEZE OUT
A HUNDREDTH OR TWO.

FIRE WX PARAMETERS WILL BE ENHANCED THURSDAY ACROSS THE ERN ZONES
WITH LOW MIN RH...BUT SFC WINDS SHOULD REMAIN BELOW CRITICAL LEVELS.
WILL CONTINUE TO MONITOR.

INTO THE BEYOND...FOR THE MOMENT GOOD CONTINUITY (ASTERISK) EXISTS
BETWEEN GFS AND EURO THRU SUNDAY BEFORE SOME DIVERGENCE ENSUES.
(ASTERISK)...THERE HAVE BEEN A MULTITUDE OF TEMPORAL AND SPATIAL
ISSUES BETWEEN ALL LR MDLS OVR THE PAST FEW DAYS CONCERNING THIS
TIME PERIOD...SO EVEN WITH CONTINUITY...OVERALL CONFIDENCE OF HOW
THE EVENT WILL UNFOLD IS STILL LOW IN MOST RESPECTS.

HOWEVER...THE OVERALL TREND DICTATES SLOWER DEVELOPMENT AS PER THE
EURO...AND A DEEPER NEGATIVELY TILTED CLOSE LOW SOLUTION A LA THE
GFS. WHAT THIS MEANS TO THE FA MAINLY HAS TO DO WITH THE CONTINUED
DELAY IN INCREASING PRECIPITATION CHCS ACROSS THE REGION AS BOTH
SPEED AND ORIENTATION OF THE DEVELOPING TROF LEAN THIS WAY. ATTM
THERE WILL BE ONLY SOME TIMING CHANGES TO THE SAT/SUN PORTION OF THE
POP/WX AND TEMP GRIDS...WITH THE REST OF THE EXTENDED FROM SUN NIGHT
ONWARD VIRTUALLY LEFT ALONE CONSIDERING THE CONTINUED UNCERTAINTY.
AS AN FYI...IT LOOKS LIKE SNOW WILL POSSIBLY RETURN TO THE FCST AT
LOWER ELEVATIONS JUST BEYOND THE END OF THIS FCST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

ISOLATED THUNDERSTORMS ARE EXPECTED IN AND AROUND THE NORTHERN
MOUNTAINS THROUGH 01Z OTHERWISE EXPECT DRY AND VFR CONDITIONS.
PATCHY FOG WILL BE POSSIBLE TONIGHT IN THE FAR WEST VALLEYS POSSIBLY
IMPACTING KJAC...KBPI AND KPNA BETWEEN 09Z-15Z WEDNESDAY.
OTHERWISE...WEDNESDAY WILL BE CLEAR AND DRY.

&&

.FIRE WEATHER...

A WARM AND DRY RIDGE WILL BUILD ACROSS WYOMING INTO THE MIDDLE OF
THE WEEK. A WEAK UPPER LEVEL DISTURBANCE MOVING THROUGH
TODAY WILL BRING ISOLATED AFTERNOON THUNDERSTORMS TO MAINLY THE
NORTHWEST MOUNTAINS UNTIL 01Z BUT MOST AREAS WILL REMAIN DRY.
RELATIVE HUMIDITY WILL FALL INTO THE TEENS ACROSS MUCH OF
FREMONT...NATRONA AND SWEETWATER COUNTIES WEDNESDAY AND EXTEND TO OF
THE LOWER ELEVATIONS THURSDAY AND FRIDAY. HIGH TEMPERATURES WILL BE
IN THE UPPER 70S TO UPPER 80S WEDNESDAY AND 80S TO LOWER 90S
THURSDAY AND FRIDAY ACROSS THE LOWER ELEVATIONS. HOWEVER...WITH WIND
EXPECTED TO REMAIN LIGHT TO MODERATE CRITICAL FIRE CONDITIONS ARE
NOT EXPECTED AT THIS TIME.

&&

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

&&

$$

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














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