Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 071741
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1141 AM MDT TUE JUL 7 2015

.UPDATE...
THUNDERSTORMS ALREADY FIRING ACROSS THE WIND RIVERS AND ERN
FREMONT COUNTY AS A MID LEVEL CIRCULATION RIGHT ON TOP OF US IS
AIDING IN THE EARLY CONVECTION. WITH PW`S UP NEAR AN INCH AND
TEMPERATURES WARMING TO AROUND 70 ALREADY...CAPES ARE BUILDING
WITH CIN ABOUT GONE. HAVE DECIDED TO EXPAND THE FLASH FLOOD
NORTHWARD TO INCLUDE MOST OF FREMONT AND NATRONA COUNTIES THROUGH
10 PM DUE TO RISK OF HEAVY RAIN PRODUCING TSTMS WITH MODEST
MOVEMENT AND OR TRAINING OVER HIGHER TERRAIN.

&&

.PREV DISCUSSION... /ISSUED 326 AM MDT TUE JUL 7 2015/

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT

WV IMAGERY SHOWS BROAD TROF ACROSS THE NRN TIER OF STATES...WITH
FLAT NWLY FLOW ACROSS WY...AND A COL SITTING OFF THE CALIFORNIA
COAST. WARM MOIST SUB-TROPICAL AIR BEING FUNNELED INTO THE AREA FROM
THE SOUTHWEST. SFC HAS HIGH P ACROSS THE NRN AND HIGH PLAINS...WITH
WEAK LOW P OVR THE NRN GREAT BASIN AND ASSOCIATED WEAK STATIONARY
FRONT IN BETWEEN.

OVERALL...HEAVY RAIN SHOWERS/THUNDER POSSIBLE AGAIN TODAY AND
WEDNESDAY WITH INCREASED FLASH FLOOD POTENTIAL ACROSS THE SOUTH AND
SOUTHWESTERN ZONES.

DEEP WARM TROPICAL ATMOSPHERE ACROSS THE SRN ZONES WITH PWS HOVERING
AROUND 1 INCH PLUS/MINUS. RELATIVELY LOW SHEAR AND LOW CAPE. SFC
FRONT WAVERS AROUND THE SRN ZONES TODAY BEFORE MOVING S THRU/OUT OF
THE CWA THIS AFTERNOON. ALONG AND POST FRONTAL FORCING...ALTHOUGH
WEAK...WILL HELP IN GETTING SHOWERS AND THUNDER GOING/SUSTAINING
ACROSS THE SRN FA. STORMS WILL ALSO HAVE GENERALLY SLOW MOVING AT
< = 15 KTS FROM NW TO SE/N TO S. HAVE ISSUED A FLASH FLOOD WATCH
GOOD FROM 18Z UNTIL 04Z WED...FOR THESE POTENTIAL HEAVY RAIN
PRODUCERS PUTTING DOWN PRECIP OVR GROUND THAT HAS ALREADY TAKEN UP
TO AN INCH IN PLACES EARLIER TONIGHT. OTHER THAN SOME FF POTENTIAL
WITH HEAVIER RAIN CORES...THERE WILL BE A SMALL THREAT OF WET MICRO-
BURSTS AND SMALL HAIL MOSTLY < 1/2 INCH. SIMILAR SET-UP WEDNESDAY.
WILL HAVE TO REASSESS FOR THE POSSIBILITY OF ANOTHER FF
WATCH...BASED ON TODAY`S RAINFALL TO SOME EXTENT.

THURSDAY...THE FA BEGINS TO WARM AND DRY OUT OUT. CAPE WILL INCREASE
BUT SHEAR WILL REMAIN ON THE LOWER SIDE...WITH LESS CHCS FOR PRECIP
OVERALL...BUT WITH A RETURN TO MORE THUNDER...LESS SHOWERS...GUSTY
WIND AND SMALL HAIL TYPE STORMS AS A EMBEDDED SW TROF LIFTS UP OUT
OF THE SW CONUS AND HELPS TO TRIGGER CONVECTION OVR THE WRN
MOUNTAINS AND POSSIBLE STATIONARY FRONT. FLASH FLOOD POTENTIAL
SHOULD BE LESS OVERALL THIS DAY WITH STORMS BOTH MOVING FASTER AND
HAVING LESS PW TO WORK WITH.

.LONG TERM...FRIDAY THROUGH TUESDAY

THE WEATHER SYSTEM MOVES THROUGH NORTHERN UTAH FRIDAY AND ACROSS
IDAHO AND WESTERN WY FRIDAY NIGHT...THEN INTO MONTANA BY SATURDAY
MORNING. GFS AND ECMWF MODELS CLOSE WITH THE TIMING OF THIS SYSTEM
WITH THE TRACK FAVORING WESTERN WY FOR PRECIP POTENTIAL. SCATTERED
SHOWERS/STORMS FOR THE WEST FRI INTO FRI NIGHT. ISOLATED ACTIVITY
IN THE CENTRAL AND EAST ZONES FRIDAY AFTERNOON AND NIGHT. DRIER
CONDITIONS SATURDAY. HOWEVER...STILL A SLIGHT CHANCE OF STORMS
OVER THE WEST AND NORTH AS MOISTURE LINGERS ALONG WITH A FRONTAL
BOUNDARY THAT RESIDES ACROSS NW/N WY. SUNDAY LOOKS MOSTLY DRY
WITH ONLY ISOLATED AFTERNOON/EVENING STORMS IN THE WESTERN
MOUNTAINS. MONDAY LOOKS DRY FOR MOST PLACES WITH ISOLATED
AFTERNOON AND EVENING STORMS FOR THE WESTERN MOUNTAINS ONCE AGAIN.
THE ECMWF AND GFS MODELS SHOW MONDAY TO BE MOSTLY DRY AND THE
HOTTEST DAY WITH A HINT OF ISOLATED STORMS OVER OR NEAR THE
MOUNTAINS. NEXT TUESDAY MOISTURE RETURNS TO THE REGION WITH WIDELY
SCATTERED THUNDERSTORMS FOR THE AFTERNOON AND EVENING. AS FOR HIGH
TEMPS...FRIDAY WILL BE SEASONABLY WARM...THEN GRADUALLY WARMER
SAT/SUN/MON WITH MONDAY BEING THE HOTTEST DAY. SLIGHTLY COOLER
HIGHS NEXT TUE WITH MORE CLOUD COVER.

.AVIATION.../18Z ISSUANCE/

ACTIVE SHOWER AND THUNDERSTORM PERIOD THROUGH WEDNESDAY. MOST TAF
SITES FROM KJAC TO KCPR WILL BE AT RISK OF THUNDERSTORMS IN THE
VICINITY DURING THE AFTERNOON AND EVENING HOURS ALONG WITH
MOUNTAIN OBSCURATION AT TIMES. MORE ISOLATED COVERAGE ACROSS THE
FAR NORTH TODAY BUT STILL A FEW AROUND...ESPECIALLY IN AND NEAR
THE MOUNTAINS.

.FIRE WEATHER...

FIRE DANGER WILL REMAIN BELOW RELATIVELY LOW TODAY AND WEDNESDAY AS
THE ATMOSPHERE REMAINS CHARGE WITH MOISTURE ACROSS MUCH OF THE
FORECAST AREA AND FUELS REMAIN IN GREEN-UP. HOWEVER...FIRE DANGER
WILL BE SLIGHTLY ENHANCED BOTH DAYS...PARTICULARLY ACROSS THE
WESTERN AND NORTHWESTERN FORECAST AREA...AS A COUPLE OF FIRE STARTS
DUE TO LIGHTNING STRIKES WILL BE POSSIBLE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR WYZ014-015-
017>020-022>024-026>030.

&&

$$

UPDATE...PS
SHORT TERM...BRAUN
LONG TERM...AR
AVIATION...PS
FIRE WEATHER...BRAUN


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