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000
FXUS65 KRIW 220515
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1115 PM MDT THU AUG 21 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 217 PM MDT)

SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE INTO THE EVENING BUT
WITHOUT ANY SIGNIFICANT FORCING...ACTIVITY IS EXPECTED TO BE WEAK
AND WILL DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST THIS
EVENING. THE MODELS HAVE SLOWED DOWN A BIT WITH THE PROGRESSION OF
THE NEXT TROUGH SO INSTEAD OF SHOWERS DEVELOPING BY SUNRISE THEY ARE
EXPECTED TO START A BIT LATER TOWARD NOON ON FRIDAY WHEN WIDESPREAD
SHOWERS WILL DEVELOP OVER WESTERN WY AND WILL SPREAD TOWARD CENTRAL
WY AFTER 21Z FRIDAY ONCE THE NEGATIVELY TILTED TROUGH OVER THE PAC
NW CLOSES OFF OVER WASHINGTON AND OREGON AND THE SOUTHWEST FLOW
AHEAD OF THIS LOW INCREASES. IT ALSO LOOKS LIKE THE
ATTENDANT DYNAMICS WILL HOLD OFF UNTIL THE BEGINNING OF THE LONG
TERM PERIOD AS WELL...BUT A COLD FRONT WILL TRY TO DIP INTO NORTHERN
AND WESTERN WYOMING LATE IN THE PERIOD...WITH SOME ENHANCEMENT
EXPECTED ALONG AND BEHIND THE FRONT...SO OVERALL FRIDAY WILL BE A
SHOWERY DAY WITH A FEW THUNDERSTORMS POSSIBLE ACROSS THE NORTH AND
WEST WITH SOME TEMPERATURE REBOUND EAST OF THE DIVIDE IN THE
SOUTHWEST FLOW WHILE THE WEST AND NORTH REMAIN UNSEASONABLY COOL.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...EXTENDED WILL BE CHARACTERIZED BY BELOW AVG TEMPS AND MUCH
HIGHER THAN NORMAL PRECIPITATION CHANCES.

FRI NIGHT THRU SUNDAY...CYCLO/FRONTO GENESIS ONGOING OVR THE FA FRI
NIGHT WITH THE APPROACH OF THE W/NW CONUS TROF. FRONT/BOUNDARY(S)
CUTTING DIAGONALLY FROM SW TO NCNTRL WY W/ LOW OVR CNTRL WY. TWO
DISTINCT MOISTURE SOURCES...ONE FROM THE MONSOONALISH DESERT SW/SRN
ROCKIES...THE OTHER FROM THE EPAC...WITH BOTH OF THOSE AREAS COMING
TOGETHER INTO THE NRN HIGH AND NRN PLAINS...NE OF THIS FA.
ISOLATED TO WIDELY SCATTERED SHRA/TSRA AHEAD OF LOW/FRONT...
SCATTERED TO NUMEROUS SHRA/ISO TSRA BEHIND OVR THE W/NW CWA.
CHANGEOVER TO SOME LIGHT SNOWFALL OVERNIGHT FOR ELEVATIONS ABOVE
10500 FT TO BEGIN WITH FRI NIGHT...FALLING TO 9000 TO 9500 FT BY
SAT NIGHT. IN THESE AREAS...EXPECT 12 HRS SNOWFALL TOTALS DURING
THE EVENING/OVERNIGHT PERIODS TO EXTEND UP TO A COUPLE OF INCHES
EACH NIGHT AT THE HIGHER ELEVATIONS...WITH LOCALIZED AREAS
SATURDAY NIGHT RECEIVING UP TO 3 INCHES. WITH THE STRONG UPR TROF
TAKING ITS TIME TO MOVE ACROSS THE REGION...COUNTING AT LEAST TWO
BONAFIDE FRONTAL PUSHES BETWEEN FRI NIGHT AND SUN NIGHT.
ATTM...SAT/SAT NIGHT LOOKS TO BE THE BUSIEST OF THE NEAR FCST
PERIOD AS LEE SIDE LOW DEVELOPS OVR ERN/SERN WY DOWN TO THE S INTO
ERN CO...PULLING ANOTHER QUICKLY DEVELOPING SFC LOW AND FRONT THRU
THE FA DURING THE EVENING/OVERNIGHT PERIOD(S). STRONGER STORMS
PERHAPS ACROSS NATRONA COUNTY FOR A COUPLE OF HRS LATE
AFTERNOON/EARLY EVENING. SUNDAY...POST FRONTAL WITH (FINALLY)
EXITING UPR TROF. EMPHASIS WILL BE ON THE COOL TEMPERATURES LEFT
OVER...SKIES TRYING TO CLEAR SOME FROM SOUTH TO NORTH...AND MOST
PRECIP CHCS BEING RELEGATED TO THE NRN/NWRN FA...ESPECIALLY THE
MOUNTAINS WHERE BOTH TERRAIN FORCING AND INSTABILITY WILL BE
MAXIMIZED.

MONDAY AND BEYOND...WHERE PREVIOUS LR MDL RUNS HAD THE GFS AND EURO
DIVERGING QUITE A BIT W/ RESPECT TO HANDLING ANOTHER WRN CONUS
TROF...THE EURO HAS COME AROUND TO THE GFS (AND OTHER MDLS) WAY OF
THINKING ...KEEPING THE TROF MORE PROGRESSIVE AND NOT CUTTING IT OFF
IN THE GREAT BASIN AS BEFORE. ACTUAL SIMILARITIES BETWEEN MDLS NOW
REMAIN GOOD AND CONSISTENT THRU NEXT THU....FROM THE UPR LVLS DOWN
TO THE SFC. NEXT STORM/RAINIEST PERIOD CONTINUES TO LOOK LIKE MON
NIGHT THRU TUE MORNING...W/ LITTLE AS NEXT UPR TROF WAVE AXIS AND
SFC FRONT PUSHES THRU W/ SOME CHC FOR PRECIP EVERYWHERE ONCE AGAIN.
FROM WED THRU THU...PRECIP CHCS DROP CONSIDERABLY AND BECOME MORE
DIURNAL WITH EXITING TROF ALOFT TRANSITIONING TO MODEST
RIDGING.

&&

.AVIATION.../06Z ISSUANCE/

SHOWERS AND ISOLATED STORMS WILL OCCUR OVER WESTERN WY UNTIL 11Z
FROM KBPI TO KCOD. LOCAL MVFR CONDITIONS WILL OCCUR IN NW WY.
LOW CLOUDS ARE POSSIBLE IN NORTHERN WY AND FROM KBYG TO KCPR UNTIL
16Z WITH MVFR CONDITIONS. OTHERWISE VFR CONDITIONS WILL OCCUR
THROUGH 19Z. SHOWERS AND THUNDERSTORMS WILL FORM OVER THE WEST AND
SOUTH AFTER 19Z AND SPREAD NORTHEAST ACROSS THE CENTRAL AND NORTH
DURING THE AFTERNOON AND EVENING HOURS. AREAS OF MVFR CONDITIONS
WILL OCCUR ACROSS THE REGION IN AREAS OF HEAVIER RAIN ASSOCIATED
WITH STRONGER STORMS. SHOWERS AND STORMS WILL DECREASE AFTER 03Z
SATURDAY AND WILL BECOME ISOLATED AROUND 06Z SATURDAY.

&&

.FIRE WEATHER...

THE ACTIVE AND WET PATTERN CONTINUES WITH A HIGH LIKELIHOOD OF
WETTING RAIN THROUGH SATURDAY FOR THE ENTIRE FORECAST AREA...WITH
THE MOST RAIN...AND POSSIBLY HIGH ELEVATION SNOW...POSSIBLE ACROSS
THE WEST AND NORTH. A POTENT PACIFIC STORM SYSTEM WILL APPROACH THE
AREA LATER TONIGHT WITH NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
SPREADING FROM NORTHWEST TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY
AND INTO SATURDAY. COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER
SYSTEM WITH SNOW LEVELS LOWERING TO 8000 FEET IN THE NORTHERN
MOUNTAINS BY LATE SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER
ELEVATIONS BY SATURDAY WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE
GENERALLY LIGHT EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS
WELL AS DURING THE COLD FRONTAL PASSAGE THIS WEEKEND.

&&

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

&&

$$

SHORT TERM...ALLEN
LONG TERM...BRAUN
AVIATION...AR
FIRE WEATHER...ALLEN









000
FXUS65 KRIW 220515
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1115 PM MDT THU AUG 21 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 217 PM MDT)

SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE INTO THE EVENING BUT
WITHOUT ANY SIGNIFICANT FORCING...ACTIVITY IS EXPECTED TO BE WEAK
AND WILL DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST THIS
EVENING. THE MODELS HAVE SLOWED DOWN A BIT WITH THE PROGRESSION OF
THE NEXT TROUGH SO INSTEAD OF SHOWERS DEVELOPING BY SUNRISE THEY ARE
EXPECTED TO START A BIT LATER TOWARD NOON ON FRIDAY WHEN WIDESPREAD
SHOWERS WILL DEVELOP OVER WESTERN WY AND WILL SPREAD TOWARD CENTRAL
WY AFTER 21Z FRIDAY ONCE THE NEGATIVELY TILTED TROUGH OVER THE PAC
NW CLOSES OFF OVER WASHINGTON AND OREGON AND THE SOUTHWEST FLOW
AHEAD OF THIS LOW INCREASES. IT ALSO LOOKS LIKE THE
ATTENDANT DYNAMICS WILL HOLD OFF UNTIL THE BEGINNING OF THE LONG
TERM PERIOD AS WELL...BUT A COLD FRONT WILL TRY TO DIP INTO NORTHERN
AND WESTERN WYOMING LATE IN THE PERIOD...WITH SOME ENHANCEMENT
EXPECTED ALONG AND BEHIND THE FRONT...SO OVERALL FRIDAY WILL BE A
SHOWERY DAY WITH A FEW THUNDERSTORMS POSSIBLE ACROSS THE NORTH AND
WEST WITH SOME TEMPERATURE REBOUND EAST OF THE DIVIDE IN THE
SOUTHWEST FLOW WHILE THE WEST AND NORTH REMAIN UNSEASONABLY COOL.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...EXTENDED WILL BE CHARACTERIZED BY BELOW AVG TEMPS AND MUCH
HIGHER THAN NORMAL PRECIPITATION CHANCES.

FRI NIGHT THRU SUNDAY...CYCLO/FRONTO GENESIS ONGOING OVR THE FA FRI
NIGHT WITH THE APPROACH OF THE W/NW CONUS TROF. FRONT/BOUNDARY(S)
CUTTING DIAGONALLY FROM SW TO NCNTRL WY W/ LOW OVR CNTRL WY. TWO
DISTINCT MOISTURE SOURCES...ONE FROM THE MONSOONALISH DESERT SW/SRN
ROCKIES...THE OTHER FROM THE EPAC...WITH BOTH OF THOSE AREAS COMING
TOGETHER INTO THE NRN HIGH AND NRN PLAINS...NE OF THIS FA.
ISOLATED TO WIDELY SCATTERED SHRA/TSRA AHEAD OF LOW/FRONT...
SCATTERED TO NUMEROUS SHRA/ISO TSRA BEHIND OVR THE W/NW CWA.
CHANGEOVER TO SOME LIGHT SNOWFALL OVERNIGHT FOR ELEVATIONS ABOVE
10500 FT TO BEGIN WITH FRI NIGHT...FALLING TO 9000 TO 9500 FT BY
SAT NIGHT. IN THESE AREAS...EXPECT 12 HRS SNOWFALL TOTALS DURING
THE EVENING/OVERNIGHT PERIODS TO EXTEND UP TO A COUPLE OF INCHES
EACH NIGHT AT THE HIGHER ELEVATIONS...WITH LOCALIZED AREAS
SATURDAY NIGHT RECEIVING UP TO 3 INCHES. WITH THE STRONG UPR TROF
TAKING ITS TIME TO MOVE ACROSS THE REGION...COUNTING AT LEAST TWO
BONAFIDE FRONTAL PUSHES BETWEEN FRI NIGHT AND SUN NIGHT.
ATTM...SAT/SAT NIGHT LOOKS TO BE THE BUSIEST OF THE NEAR FCST
PERIOD AS LEE SIDE LOW DEVELOPS OVR ERN/SERN WY DOWN TO THE S INTO
ERN CO...PULLING ANOTHER QUICKLY DEVELOPING SFC LOW AND FRONT THRU
THE FA DURING THE EVENING/OVERNIGHT PERIOD(S). STRONGER STORMS
PERHAPS ACROSS NATRONA COUNTY FOR A COUPLE OF HRS LATE
AFTERNOON/EARLY EVENING. SUNDAY...POST FRONTAL WITH (FINALLY)
EXITING UPR TROF. EMPHASIS WILL BE ON THE COOL TEMPERATURES LEFT
OVER...SKIES TRYING TO CLEAR SOME FROM SOUTH TO NORTH...AND MOST
PRECIP CHCS BEING RELEGATED TO THE NRN/NWRN FA...ESPECIALLY THE
MOUNTAINS WHERE BOTH TERRAIN FORCING AND INSTABILITY WILL BE
MAXIMIZED.

MONDAY AND BEYOND...WHERE PREVIOUS LR MDL RUNS HAD THE GFS AND EURO
DIVERGING QUITE A BIT W/ RESPECT TO HANDLING ANOTHER WRN CONUS
TROF...THE EURO HAS COME AROUND TO THE GFS (AND OTHER MDLS) WAY OF
THINKING ...KEEPING THE TROF MORE PROGRESSIVE AND NOT CUTTING IT OFF
IN THE GREAT BASIN AS BEFORE. ACTUAL SIMILARITIES BETWEEN MDLS NOW
REMAIN GOOD AND CONSISTENT THRU NEXT THU....FROM THE UPR LVLS DOWN
TO THE SFC. NEXT STORM/RAINIEST PERIOD CONTINUES TO LOOK LIKE MON
NIGHT THRU TUE MORNING...W/ LITTLE AS NEXT UPR TROF WAVE AXIS AND
SFC FRONT PUSHES THRU W/ SOME CHC FOR PRECIP EVERYWHERE ONCE AGAIN.
FROM WED THRU THU...PRECIP CHCS DROP CONSIDERABLY AND BECOME MORE
DIURNAL WITH EXITING TROF ALOFT TRANSITIONING TO MODEST
RIDGING.

&&

.AVIATION.../06Z ISSUANCE/

SHOWERS AND ISOLATED STORMS WILL OCCUR OVER WESTERN WY UNTIL 11Z
FROM KBPI TO KCOD. LOCAL MVFR CONDITIONS WILL OCCUR IN NW WY.
LOW CLOUDS ARE POSSIBLE IN NORTHERN WY AND FROM KBYG TO KCPR UNTIL
16Z WITH MVFR CONDITIONS. OTHERWISE VFR CONDITIONS WILL OCCUR
THROUGH 19Z. SHOWERS AND THUNDERSTORMS WILL FORM OVER THE WEST AND
SOUTH AFTER 19Z AND SPREAD NORTHEAST ACROSS THE CENTRAL AND NORTH
DURING THE AFTERNOON AND EVENING HOURS. AREAS OF MVFR CONDITIONS
WILL OCCUR ACROSS THE REGION IN AREAS OF HEAVIER RAIN ASSOCIATED
WITH STRONGER STORMS. SHOWERS AND STORMS WILL DECREASE AFTER 03Z
SATURDAY AND WILL BECOME ISOLATED AROUND 06Z SATURDAY.

&&

.FIRE WEATHER...

THE ACTIVE AND WET PATTERN CONTINUES WITH A HIGH LIKELIHOOD OF
WETTING RAIN THROUGH SATURDAY FOR THE ENTIRE FORECAST AREA...WITH
THE MOST RAIN...AND POSSIBLY HIGH ELEVATION SNOW...POSSIBLE ACROSS
THE WEST AND NORTH. A POTENT PACIFIC STORM SYSTEM WILL APPROACH THE
AREA LATER TONIGHT WITH NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
SPREADING FROM NORTHWEST TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY
AND INTO SATURDAY. COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER
SYSTEM WITH SNOW LEVELS LOWERING TO 8000 FEET IN THE NORTHERN
MOUNTAINS BY LATE SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER
ELEVATIONS BY SATURDAY WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE
GENERALLY LIGHT EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS
WELL AS DURING THE COLD FRONTAL PASSAGE THIS WEEKEND.

&&

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

&&

$$

SHORT TERM...ALLEN
LONG TERM...BRAUN
AVIATION...AR
FIRE WEATHER...ALLEN










000
FXUS65 KRIW 212017
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
217 PM MDT THU AUG 21 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY

SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE INTO THE EVENING BUT
WITHOUT ANY SIGNIFICANT FORCING...ACTIVITY IS EXPECTED TO BE WEAK
AND WILL DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST THIS
EVENING. THE MODELS HAVE SLOWED DOWN A BIT WITH THE PROGRESSION OF
THE NEXT TROUGH SO INSTEAD OF SHOWERS DEVELOPING BY SUNRISE THEY ARE
EXPECTED TO START A BIT LATER TOWARD NOON ON FRIDAY WHEN WIDESPREAD
SHOWERS WILL DEVELOP OVER WESTERN WY AND WILL SPREAD TOWARD CENTRAL
WY AFTER 21Z FRIDAY ONCE THE NEGATIVELY TILTED TROUGH OVER THE PAC
NW CLOSES OFF OVER WASHINGTON AND OREGON AND THE SOUTHWEST FLOW
AHEAD OF THIS LOW INCREASES. IT ALSO LOOKS LIKE THE
ATTENDANT DYNAMICS WILL HOLD OFF UNTIL THE BEGINNING OF THE LONG
TERM PERIOD AS WELL...BUT A COLD FRONT WILL TRY TO DIP INTO NORTHERN
AND WESTERN WYOMING LATE IN THE PERIOD...WITH SOME ENHANCEMENT
EXPECTED ALONG AND BEHIND THE FRONT...SO OVERALL FRIDAY WILL BE A
SHOWERY DAY WITH A FEW THUNDERSTORMS POSSIBLE ACROSS THE NORTH AND
WEST WITH SOME TEMPERATURE REBOUND EAST OF THE DIVIDE IN THE
SOUTHWEST FLOW WHILE THE WEST AND NORTH REMAIN UNSEASONABLY COOL.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

OVERALL...EXTENDED WILL BE CHARACTERIZED BY BELOW AVG TEMPS AND MUCH
HIGHER THAN NORMAL PRECIPITATION CHANCES.

FRI NIGHT THRU SUNDAY...CYCLO/FRONTO GENESIS ONGOING OVR THE FA FRI
NIGHT WITH THE APPROACH OF THE W/NW CONUS TROF. FRONT/BOUNDARY(S)
CUTTING DIAGONALLY FROM SW TO NCNTRL WY W/ LOW OVR CNTRL WY. TWO
DISTINCT MOISTURE SOURCES...ONE FROM THE MONSOONALISH DESERT SW/SRN
ROCKIES...THE OTHER FROM THE EPAC...WITH BOTH OF THOSE AREAS COMING
TOGETHER INTO THE NRN HIGH AND NRN PLAINS...NE OF THIS FA.
ISOLATED TO WIDELY SCATTERED SHRA/TSRA AHEAD OF LOW/FRONT...
SCATTERED TO NUMEROUS SHRA/ISO TSRA BEHIND OVR THE W/NW CWA.
CHANGEOVER TO SOME LIGHT SNOWFALL OVERNIGHT FOR ELEVATIONS ABOVE
10500 FT TO BEGIN WITH FRI NIGHT...FALLING TO 9000 TO 9500 FT BY
SAT NIGHT. IN THESE AREAS...EXPECT 12 HRS SNOWFALL TOTALS DURING
THE EVENING/OVERNIGHT PERIODS TO EXTEND UP TO A COUPLE OF INCHES
EACH NIGHT AT THE HIGHER ELEVATIONS...WITH LOCALIZED AREAS
SATURDAY NIGHT RECEIVING UP TO 3 INCHES. WITH THE STRONG UPR TROF
TAKING ITS TIME TO MOVE ACROSS THE REGION...COUNTING AT LEAST TWO
BONAFIDE FRONTAL PUSHES BETWEEN FRI NIGHT AND SUN NIGHT.
ATTM...SAT/SAT NIGHT LOOKS TO BE THE BUSIEST OF THE NEAR FCST
PERIOD AS LEE SIDE LOW DEVELOPS OVR ERN/SERN WY DOWN TO THE S INTO
ERN CO...PULLING ANOTHER QUICKLY DEVELOPING SFC LOW AND FRONT THRU
THE FA DURING THE EVENING/OVERNIGHT PERIOD(S). STRONGER STORMS
PERHAPS ACROSS NATRONA COUNTY FOR A COUPLE OF HRS LATE
AFTERNOON/EARLY EVENING. SUNDAY...POST FRONTAL WITH (FINALLY)
EXITING UPR TROF. EMPHASIS WILL BE ON THE COOL TEMPERATURES LEFT
OVER...SKIES TRYING TO CLEAR SOME FROM SOUTH TO NORTH...AND MOST
PRECIP CHCS BEING RELEGATED TO THE NRN/NWRN FA...ESPECIALLY THE
MOUNTAINS WHERE BOTH TERRAIN FORCING AND INSTABILITY WILL BE
MAXIMIZED.

MONDAY AND BEYOND...WHERE PREVIOUS LR MDL RUNS HAD THE GFS AND EURO
DIVERGING QUITE A BIT W/ RESPECT TO HANDLING ANOTHER WRN CONUS
TROF...THE EURO HAS COME AROUND TO THE GFS (AND OTHER MDLS) WAY OF
THINKING ...KEEPING THE TROF MORE PROGRESSIVE AND NOT CUTTING IT OFF
IN THE GREAT BASIN AS BEFORE. ACTUAL SIMILARITIES BETWEEN MDLS NOW
REMAIN GOOD AND CONSISTENT THRU NEXT THU....FROM THE UPR LVLS DOWN
TO THE SFC. NEXT STORM/RAINIEST PERIOD CONTINUES TO LOOK LIKE MON
NIGHT THRU TUE MORNING...W/ LITTLE AS NEXT UPR TROF WAVE AXIS AND
SFC FRONT PUSHES THRU W/ SOME CHC FOR PRECIP EVERYWHERE ONCE AGAIN.
FROM WED THRU THU...PRECIP CHCS DROP CONSIDERABLY AND BECOME MORE
DIURNAL WITH EXITING TROF ALOFT TRANSITIONING TO MODEST
RIDGING.

&&

.AVIATION.../00Z ISSUANCE/

AN ACTIVE PERIOD WILL CONTINUE THROUGH THIS TAF PERIOD AS WELL...AND
BEYOND INTO SATURDAY. THIS SYSTEM WILL CONTINUE TO BRING A SERIES OF
DISTURBANCES AND COLD FRONTS ALONG WITH SCT SHRA/ISOLD TSRA.

DURING THIS TAF PERIOD...MOST ACTIVITY WILL BE VCNTY AND NW OF A
KEMM-KDUB-KBYG LINE MORE ISOLD SOUTH OF THIS LINE. LCL IFR/LIFR FG
AND CIGS MAY DEVELOP IN THE WESTERN VALLEYS AFTER 09Z TONIGHT...
MAINLY VCNTY KJAC-KAFO. THE ATMOSPHERE WILL QUICKLY STABILIZE AFTER
3Z FRIDAY WITH MOST SHOWER AND THUNDERSTORM ACTIVITY MOVING NE INTO
MONTANA AND THE NORTHERN PLAINS. ISOLD-SCT TSRA WILL BLOSSOM IN THE
SAME GENERAL AREA ACROSS THE WEST AND NORTH TOMORROW AFTERNOON.

&&

.FIRE WEATHER...

THE ACTIVE AND WET PATTERN CONTINUES WITH A HIGH LIKELIHOOD OF
WETTING RAIN THROUGH SATURDAY FOR THE ENTIRE FORECAST AREA...WITH
THE MOST RAIN...AND POSSIBLY HIGH ELEVATION SNOW...POSSIBLE ACROSS
THE WEST AND NORTH. A POTENT PACIFIC STORM SYSTEM WILL APPROACH THE
AREA LATER TONIGHT WITH NUMEROUS SHOWERS AND A FEW THUNDERSTORMS
SPREADING FROM NORTHWEST TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY
AND INTO SATURDAY. COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER
SYSTEM WITH SNOW LEVELS LOWERING TO 8000 FEET IN THE NORTHERN
MOUNTAINS BY LATE SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER
ELEVATIONS BY SATURDAY WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE
GENERALLY LIGHT EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS
WELL AS DURING THE COLD FRONTAL PASSAGE THIS WEEKEND.

&&

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

$$

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






000
FXUS65 KRIW 211738 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1138 AM MDT THU AUG 21 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO ERUPT OVER EASTERN
IDAHO AS THE VORT LOBE OF THE NIGHT MOVES ON THROUGH CENTRAL WY
WITH THE NEXT VORT FOLLOWING CLOSE BEHIND OVER THE GREAT SALT
LAKE. AS A RESULT THERE WILL BE PLENTY OF RESIDUAL SHOWERS ACROSS
WESTERN AND NORTHERN WY THIS MORNING. THE LAST AFOREMENTIONED
SHORTWAVE WILL TRACK ACROSS WESTERN AND CENTRAL WYOMING TODAY FOR
AN EARLY SHOW OF CONVECTION BEFORE A TRANSITORY RIDGE BUILDS OVER
THE AREA LATER THIS AFTERNOON. AFTER 00Z FRIDAY... PRECIP WILL
DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST. THEN AFTER
06Z FRIDAY...WIDESPREAD SHOWERS WILL DEVELOP OVER WESTERN WY AND
WILL SPREAD TOWARD CENTRAL WY AFTER 12Z FRIDAY ONCE THE NEGATIVELY
TILTED TROUGH OVER THE PAC NW CLOSES OFF OVER WASHINGTON AND
OREGON AND THE SOUTHWEST FLOW AHEAD OF THIS LOW INCREASES FROM THE
SOUTHWEST. FRIDAYS PRECIP WILL BE VERY DYNAMICALLY INDUCED ON A
SYNOPTIC SCALE...FIRST TIME IN A WHILE. QG FORCING IS PROGGED FOR
NW AND SOUTHERN WY FRIDAY WITH QG FORCING SPREADING TO NATRONA
COUNTY FRI NT. THE ASCT MID LEVEL CIRCULATION WILL TRACK TO IDAHO
FRIDAY NIGHT. SATURDAY LOOKS TO BE A COOL WET DAY AS THE MAIN LOW
APPROACHES THE NORTHERN ROCKIES. EXPECT LEFT FRONT QUAD DYNAMICS
OVER NW WY SATURDAY ONCE THE H5 LOW REACHES THE MT/ID BORDER ACDG
TO THE GFS WITH THE NAM A LITTLE FASTER TAKING IT TO CENTRAL MT.
ON SATURDAY THE MID LEVEL CIRCULATION IS PROGGED TO TRACK FROM YNP
TO AROUND HOT SPRINGS COUNTY AND THEN JOHNSON COUNTY BY SAT EVE.
TO THE NORTH OF THE H7 LOW OVER THE NORTHERN BORDER OF WY...EVEN
SOME WRAP AROUND ISENTROPIC LIFT IS EXPECTED. SFC CYCLOGENESIS IS
EXPECTED OVER SE WY. MOIST COOLER AIR WILL WRAP AROUND BEHIND
THESE CIRCULATIONS SATURDAY NIGHT AS A STRONG COLD FRONT MOVES
SOUTHEAST ACROSS WY. EXPECT NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS TO OVERSPREAD THE AREA FRIDAY NIGHT AND INTO
SATURDAY WITH THE INCREASING GRADIENT OF SHOWER ACTIVITY RUNNING
SOUTH TO NORTH AND THEN OVERSPREADING THE WHOLE STATE BY LATE
SATURDAY. AS THE SYSTEM GRADUALLY PULLS OUT OF THE AREA SATURDAY
NIGHT...H7 TEMPS WILL DROP TO -1C IN NW WY WHICH WILL BRING SNOW
LEVELS THERE FROM 10500 FEET SATURDAY MORNING TO 8000 FEET BY 12Z
SUNDAY. THE HIGHER PEAKS ELSEWHERE WILL ALSO SEE SNOW FROM ANY
LINGERING SHOWERS BY 12Z SUNDAY AS WELL. COULD SEE UP TO AN INCH
AND A HALF OF SNOWFALL IN THE BIG HORN MOUNTAINS BY EARLY SUNDAY
MORNING AND AN INCH IN THE ABSAROKAS. HIGH TEMPS IN MOST LOWER
ELEVATIONS SATURDAY WILL STRUGGLE TO GET ABOVE 70.

.LONG TERM...SUNDAY THROUGH THURSDAY
SATURDAY`S STORM SYSTEM WILL LIKELY BE OFF TO OUR EAST TO START THIS
PERIOD WITH JUST A LITTLE BIT OF MOISTURE AND INSTABILITY LEFT
BEHIND IN THE FAR NRN MOUNTAINS WHERE SOME SUNDAY SHOWERS/ISOLD
THUNDERSTORMS ARE EXPECTED. OTHERWISE...A COOL TO MILD DAY WITH
HIGHS ONLY IN THE 60S TO LOWER 70S WITH 50S AND SOME 60S IN THE HIGH
COUNTRY. THE NEXT MAJOR COOL TROUGH WHICH ORIGINATES FROM THE FAR
WRN ALEUTIAN LOW IS EXPECTED TO STRENGTHEN AS IT DROPS SE INTO THE
MEAN TROUGH. LEANING TOWARDS THE GFS/GEM IDEA AGAIN TONIGHT AND
NOT THE ECMWF WITH ITS DEVELOPING CUTOFF LOW OVER ERN CA AND NV ON
TUESDAY. THERE ARE A FEW GFS ENSEMBLE MEMBERS THAT ARE LEANING THAT WAY
BUT MOST KEEP THE TROUGH IN THE FLOW AND OVER THE ROCKIES REGION.
WORTH WATCHING BUT IT WOULD BE UNUSUAL TO SEE THAT STRONG OF A
CUTOFF LOW IN AUGUST THAT FAR SOUTH. SO GOING WITH THE GFS
IDEA...MAIN IMPACT DURING THE DAY MONDAY WITH CURRENT TIMING IS
THE NW AND POSSIBLY A SWATH IN THE FAR SERN ZONES BUT THEN MONDAY
NIGHT THE ASSOCIATED MID LEVEL CIRCULATION MAY MOVE RIGHT ACROSS
OUR FORECAST AREA BRINGING A GOOD CHANCE OF SHOWERS AND EMBEDDED
THUNDER MONDAY NIGHT AND TUESDAY MORNING IN OUR CENTRAL AND ERN
SECTIONS. A WARMER DAY EAST OF THE DIVIDE ON MONDAY ALONG WITH
INCREASING WIND AHEAD OF THIS SYSTEM. INLAND TRAJECTORY SHOULD
BRING DOWN SOME PRETTY COOL AIR FOR LATE AUGUST WITH SNOW LEVELS
LOWERING TO BETWEEN 8K AND 9K FEET MONDAY NIGHT IN OUR CENTRAL AND
NRN MOUNTAINS. DRY WITH A WARMING TREND WEDNESDAY THROUGH THURSDAY
AS SHORTWAVE RIDGING MOVES IN. STILL BELOW NORMAL TEMPS WEDNESDAY
AND THEN BACK TO AROUND NORMAL BY THURSDAY.

&&

.AVIATION.../18Z ISSUANCE/

AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL CONTINUE TO LIFT
NORTHEAST INTO S CEN MT EARLY THIS AFTERNOON. THIS SYSTEM WILL
CONTINUE TO BRING SCT SHRA/ISOLD TSRA MAINLY VCNTY AND NW OF A
KEMM-KDUB-KBYG LINE. ACTIVITY WILL BE MORE ISOLD SOUTH OF THIS
LINE. LCL IFR/LIFR FG AND CIGS MAY DEVELOP IN THE WESTERN VALLEYS
THROUGH AFTER 09Z TONIGHT...MAINLY VCNTY KJAC- KAFO. ISOLD-SCT
TSRA WILL BLOSSOM IN THE SAME GENERAL AREA ACROSS THE WEST AND
NORTH THIS AFTERNOON. THE ATMOSPHERE WILL QUICKLY STABILIZE AFTER
3Z FRIDAY WITH MOST SHOWER AND THUNDERSTORM ACTIVITY MOVING NE
INTO MONTANA AND THE NORTHERN PLAINS.

&&

.FIRE WEATHER...
SHOWERS WILL BE PREVALENT THIS MORNING WITH THUNDERSTORMS SHORT TO
FOLLOW THROUGH MID AFTERNOON,. THERE WILL BE A BREAK IN THE ACTION
LATER THIS AFTERNOON AND EVENING AS A SHORT LIVED HIGH PRESSURE
RIDGE BUILDS OVER THE AREA EXCEPT FOR NORTHWEST WYOMING WHERE
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. A POTENT
PACIFIC STORM SYSTEM WILL APPROACH THE AREA LATER TONIGHT WITH
NUMEROUS SHOWERS AND A FEW THUNDERSTORMS SPREADING FROM NORTHWEST
TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY AND INTO SATURDAY.
COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER SYSTEM WITH SNOW
LEVELS LOWERING TO 8000 FEET IN THE NORTHERN MOUNTAINS BY LATE
SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER ELEVATIONS BY SATURDAY
WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE GENERALLY LIGHT
EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS WELL AS DURING
THE COLD FRONTAL PASSAGE LATER THIS WEEK.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON














000
FXUS65 KRIW 211738 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1138 AM MDT THU AUG 21 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO ERUPT OVER EASTERN
IDAHO AS THE VORT LOBE OF THE NIGHT MOVES ON THROUGH CENTRAL WY
WITH THE NEXT VORT FOLLOWING CLOSE BEHIND OVER THE GREAT SALT
LAKE. AS A RESULT THERE WILL BE PLENTY OF RESIDUAL SHOWERS ACROSS
WESTERN AND NORTHERN WY THIS MORNING. THE LAST AFOREMENTIONED
SHORTWAVE WILL TRACK ACROSS WESTERN AND CENTRAL WYOMING TODAY FOR
AN EARLY SHOW OF CONVECTION BEFORE A TRANSITORY RIDGE BUILDS OVER
THE AREA LATER THIS AFTERNOON. AFTER 00Z FRIDAY... PRECIP WILL
DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST. THEN AFTER
06Z FRIDAY...WIDESPREAD SHOWERS WILL DEVELOP OVER WESTERN WY AND
WILL SPREAD TOWARD CENTRAL WY AFTER 12Z FRIDAY ONCE THE NEGATIVELY
TILTED TROUGH OVER THE PAC NW CLOSES OFF OVER WASHINGTON AND
OREGON AND THE SOUTHWEST FLOW AHEAD OF THIS LOW INCREASES FROM THE
SOUTHWEST. FRIDAYS PRECIP WILL BE VERY DYNAMICALLY INDUCED ON A
SYNOPTIC SCALE...FIRST TIME IN A WHILE. QG FORCING IS PROGGED FOR
NW AND SOUTHERN WY FRIDAY WITH QG FORCING SPREADING TO NATRONA
COUNTY FRI NT. THE ASCT MID LEVEL CIRCULATION WILL TRACK TO IDAHO
FRIDAY NIGHT. SATURDAY LOOKS TO BE A COOL WET DAY AS THE MAIN LOW
APPROACHES THE NORTHERN ROCKIES. EXPECT LEFT FRONT QUAD DYNAMICS
OVER NW WY SATURDAY ONCE THE H5 LOW REACHES THE MT/ID BORDER ACDG
TO THE GFS WITH THE NAM A LITTLE FASTER TAKING IT TO CENTRAL MT.
ON SATURDAY THE MID LEVEL CIRCULATION IS PROGGED TO TRACK FROM YNP
TO AROUND HOT SPRINGS COUNTY AND THEN JOHNSON COUNTY BY SAT EVE.
TO THE NORTH OF THE H7 LOW OVER THE NORTHERN BORDER OF WY...EVEN
SOME WRAP AROUND ISENTROPIC LIFT IS EXPECTED. SFC CYCLOGENESIS IS
EXPECTED OVER SE WY. MOIST COOLER AIR WILL WRAP AROUND BEHIND
THESE CIRCULATIONS SATURDAY NIGHT AS A STRONG COLD FRONT MOVES
SOUTHEAST ACROSS WY. EXPECT NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS TO OVERSPREAD THE AREA FRIDAY NIGHT AND INTO
SATURDAY WITH THE INCREASING GRADIENT OF SHOWER ACTIVITY RUNNING
SOUTH TO NORTH AND THEN OVERSPREADING THE WHOLE STATE BY LATE
SATURDAY. AS THE SYSTEM GRADUALLY PULLS OUT OF THE AREA SATURDAY
NIGHT...H7 TEMPS WILL DROP TO -1C IN NW WY WHICH WILL BRING SNOW
LEVELS THERE FROM 10500 FEET SATURDAY MORNING TO 8000 FEET BY 12Z
SUNDAY. THE HIGHER PEAKS ELSEWHERE WILL ALSO SEE SNOW FROM ANY
LINGERING SHOWERS BY 12Z SUNDAY AS WELL. COULD SEE UP TO AN INCH
AND A HALF OF SNOWFALL IN THE BIG HORN MOUNTAINS BY EARLY SUNDAY
MORNING AND AN INCH IN THE ABSAROKAS. HIGH TEMPS IN MOST LOWER
ELEVATIONS SATURDAY WILL STRUGGLE TO GET ABOVE 70.

.LONG TERM...SUNDAY THROUGH THURSDAY
SATURDAY`S STORM SYSTEM WILL LIKELY BE OFF TO OUR EAST TO START THIS
PERIOD WITH JUST A LITTLE BIT OF MOISTURE AND INSTABILITY LEFT
BEHIND IN THE FAR NRN MOUNTAINS WHERE SOME SUNDAY SHOWERS/ISOLD
THUNDERSTORMS ARE EXPECTED. OTHERWISE...A COOL TO MILD DAY WITH
HIGHS ONLY IN THE 60S TO LOWER 70S WITH 50S AND SOME 60S IN THE HIGH
COUNTRY. THE NEXT MAJOR COOL TROUGH WHICH ORIGINATES FROM THE FAR
WRN ALEUTIAN LOW IS EXPECTED TO STRENGTHEN AS IT DROPS SE INTO THE
MEAN TROUGH. LEANING TOWARDS THE GFS/GEM IDEA AGAIN TONIGHT AND
NOT THE ECMWF WITH ITS DEVELOPING CUTOFF LOW OVER ERN CA AND NV ON
TUESDAY. THERE ARE A FEW GFS ENSEMBLE MEMBERS THAT ARE LEANING THAT WAY
BUT MOST KEEP THE TROUGH IN THE FLOW AND OVER THE ROCKIES REGION.
WORTH WATCHING BUT IT WOULD BE UNUSUAL TO SEE THAT STRONG OF A
CUTOFF LOW IN AUGUST THAT FAR SOUTH. SO GOING WITH THE GFS
IDEA...MAIN IMPACT DURING THE DAY MONDAY WITH CURRENT TIMING IS
THE NW AND POSSIBLY A SWATH IN THE FAR SERN ZONES BUT THEN MONDAY
NIGHT THE ASSOCIATED MID LEVEL CIRCULATION MAY MOVE RIGHT ACROSS
OUR FORECAST AREA BRINGING A GOOD CHANCE OF SHOWERS AND EMBEDDED
THUNDER MONDAY NIGHT AND TUESDAY MORNING IN OUR CENTRAL AND ERN
SECTIONS. A WARMER DAY EAST OF THE DIVIDE ON MONDAY ALONG WITH
INCREASING WIND AHEAD OF THIS SYSTEM. INLAND TRAJECTORY SHOULD
BRING DOWN SOME PRETTY COOL AIR FOR LATE AUGUST WITH SNOW LEVELS
LOWERING TO BETWEEN 8K AND 9K FEET MONDAY NIGHT IN OUR CENTRAL AND
NRN MOUNTAINS. DRY WITH A WARMING TREND WEDNESDAY THROUGH THURSDAY
AS SHORTWAVE RIDGING MOVES IN. STILL BELOW NORMAL TEMPS WEDNESDAY
AND THEN BACK TO AROUND NORMAL BY THURSDAY.

&&

.AVIATION.../18Z ISSUANCE/

AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL CONTINUE TO LIFT
NORTHEAST INTO S CEN MT EARLY THIS AFTERNOON. THIS SYSTEM WILL
CONTINUE TO BRING SCT SHRA/ISOLD TSRA MAINLY VCNTY AND NW OF A
KEMM-KDUB-KBYG LINE. ACTIVITY WILL BE MORE ISOLD SOUTH OF THIS
LINE. LCL IFR/LIFR FG AND CIGS MAY DEVELOP IN THE WESTERN VALLEYS
THROUGH AFTER 09Z TONIGHT...MAINLY VCNTY KJAC- KAFO. ISOLD-SCT
TSRA WILL BLOSSOM IN THE SAME GENERAL AREA ACROSS THE WEST AND
NORTH THIS AFTERNOON. THE ATMOSPHERE WILL QUICKLY STABILIZE AFTER
3Z FRIDAY WITH MOST SHOWER AND THUNDERSTORM ACTIVITY MOVING NE
INTO MONTANA AND THE NORTHERN PLAINS.

&&

.FIRE WEATHER...
SHOWERS WILL BE PREVALENT THIS MORNING WITH THUNDERSTORMS SHORT TO
FOLLOW THROUGH MID AFTERNOON,. THERE WILL BE A BREAK IN THE ACTION
LATER THIS AFTERNOON AND EVENING AS A SHORT LIVED HIGH PRESSURE
RIDGE BUILDS OVER THE AREA EXCEPT FOR NORTHWEST WYOMING WHERE
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. A POTENT
PACIFIC STORM SYSTEM WILL APPROACH THE AREA LATER TONIGHT WITH
NUMEROUS SHOWERS AND A FEW THUNDERSTORMS SPREADING FROM NORTHWEST
TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY AND INTO SATURDAY.
COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER SYSTEM WITH SNOW
LEVELS LOWERING TO 8000 FEET IN THE NORTHERN MOUNTAINS BY LATE
SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER ELEVATIONS BY SATURDAY
WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE GENERALLY LIGHT
EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS WELL AS DURING
THE COLD FRONTAL PASSAGE LATER THIS WEEK.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...ALLEN
FIRE WEATHER...LIPSON















000
FXUS65 KRIW 210936
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
336 AM MDT THU AUG 21 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO ERUPT OVER EASTERN
IDAHO AS THE VORT LOBE OF THE NIGHT MOVES ON THROUGH CENTRAL WY
WITH THE NEXT VORT FOLLOWING CLOSE BEHIND OVER THE GREAT SALT
LAKE. AS A RESULT THERE WILL BE PLENTY OF RESIDUAL SHOWERS ACROSS
WESTERN AND NORTHERN WY THIS MORNING. THE LAST AFOREMENTIONED
SHORTWAVE WILL TRACK ACROSS WESTERN AND CENTRAL WYOMING TODAY FOR
AN EARLY SHOW OF CONVECTION BEFORE A TRANSITORY RIDGE BUILDS OVER
THE AREA LATER THIS AFTERNOON. AFTER 00Z FRIDAY... PRECIP WILL
DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST. THEN AFTER
06Z FRIDAY...WIDESPREAD SHOWERS WILL DEVELOP OVER WESTERN WY AND
WILL SPREAD TOWARD CENTRAL WY AFTER 12Z FRIDAY ONCE THE NEGATIVELY
TILTED TROUGH OVER THE PAC NW CLOSES OFF OVER WASHINGTON AND
OREGON AND THE SOUTHWEST FLOW AHEAD OF THIS LOW INCREASES FROM THE
SOUTHWEST. FRIDAYS PRECIP WILL BE VERY DYNAMICALLY INDUCED ON A
SYNOPTIC SCALE...FIRST TIME IN A WHILE. QG FORCING IS PROGGED FOR
NW AND SOUTHERN WY FRIDAY WITH QG FORCING SPREADING TO NATRONA
COUNTY FRI NT. THE ASCT MID LEVEL CIRCULATION WILL TRACK TO IDAHO
FRIDAY NIGHT. SATURDAY LOOKS TO BE A COOL WET DAY AS THE MAIN LOW
APPROACHES THE NORTHERN ROCKIES. EXPECT LEFT FRONT QUAD DYNAMICS
OVER NW WY SATURDAY ONCE THE H5 LOW REACHES THE MT/ID BORDER ACDG
TO THE GFS WITH THE NAM A LITTLE FASTER TAKING IT TO CENTRAL MT.
ON SATURDAY THE MID LEVEL CIRCULATION IS PROGGED TO TRACK FROM YNP
TO AROUND HOT SPRINGS COUNTY AND THEN JOHNSON COUNTY BY SAT EVE.
TO THE NORTH OF THE H7 LOW OVER THE NORTHERN BORDER OF WY...EVEN
SOME WRAP AROUND ISENTROPIC LIFT IS EXPECTED. SFC CYCLOGENESIS IS
EXPECTED OVER SE WY. MOIST COOLER AIR WILL WRAP AROUND BEHIND
THESE CIRCULATIONS SATURDAY NIGHT AS A STRONG COLD FRONT MOVES
SOUTHEAST ACROSS WY. EXPECT NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS TO OVERSPREAD THE AREA FRIDAY NIGHT AND INTO
SATURDAY WITH THE INCREASING GRADIENT OF SHOWER ACTIVITY RUNNING
SOUTH TO NORTH AND THEN OVERSPREADING THE WHOLE STATE BY LATE
SATURDAY. AS THE SYSTEM GRADUALLY PULLS OUT OF THE AREA SATURDAY
NIGHT...H7 TEMPS WILL DROP TO -1C IN NW WY WHICH WILL BRING SNOW
LEVELS THERE FROM 10500 FEET SATURDAY MORNING TO 8000 FEET BY 12Z
SUNDAY. THE HIGHER PEAKS ELSEWHERE WILL ALSO SEE SNOW FROM ANY
LINGERING SHOWERS BY 12Z SUNDAY AS WELL. COULD SEE UP TO AN INCH
AND A HALF OF SNOWFALL IN THE BIG HORN MOUNTAINS BY EARLY SUNDAY
MORNING AND AN INCH IN THE ABSAROKAS. HIGH TEMPS IN MOST LOWER
ELEVATIONS SATURDAY WILL STRUGGLE TO GET ABOVE 70.

.LONG TERM...SUNDAY THROUGH THURSDAY
SATURDAY`S STORM SYSTEM WILL LIKELY BE OFF TO OUR EAST TO START THIS
PERIOD WITH JUST A LITTLE BIT OF MOISTURE AND INSTABILITY LEFT
BEHIND IN THE FAR NRN MOUNTAINS WHERE SOME SUNDAY SHOWERS/ISOLD
THUNDERSTORMS ARE EXPECTED. OTHERWISE...A COOL TO MILD DAY WITH
HIGHS ONLY IN THE 60S TO LOWER 70S WITH 50S AND SOME 60S IN THE HIGH
COUNTRY. THE NEXT MAJOR COOL TROUGH WHICH ORIGINATES FROM THE FAR
WRN ALEUTIAN LOW IS EXPECTED TO STRENGTHEN AS IT DROPS SE INTO THE
MEAN TROUGH. LEANING TOWARDS THE GFS/GEM IDEA AGAIN TONIGHT AND
NOT THE ECMWF WITH ITS DEVELOPING CUTOFF LOW OVER ERN CA AND NV ON
TUESDAY. THERE ARE A FEW GFS ENSEMBLE MEMBERS THAT ARE LEANING THAT WAY
BUT MOST KEEP THE TROUGH IN THE FLOW AND OVER THE ROCKIES REGION.
WORTH WATCHING BUT IT WOULD BE UNUSUAL TO SEE THAT STRONG OF A
CUTOFF LOW IN AUGUST THAT FAR SOUTH. SO GOING WITH THE GFS
IDEA...MAIN IMPACT DURING THE DAY MONDAY WITH CURRENT TIMING IS
THE NW AND POSSIBLY A SWATH IN THE FAR SERN ZONES BUT THEN MONDAY
NIGHT THE ASSOCIATED MID LEVEL CIRCULATION MAY MOVE RIGHT ACROSS
OUR FORECAST AREA BRINGING A GOOD CHANCE OF SHOWERS AND EMBEDDED
THUNDER MONDAY NIGHT AND TUESDAY MORNING IN OUR CENTRAL AND ERN
SECTIONS. A WARMER DAY EAST OF THE DIVIDE ON MONDAY ALONG WITH
INCREASING WIND AHEAD OF THIS SYSTEM. INLAND TRAJECTORY SHOULD
BRING DOWN SOME PRETTY COOL AIR FOR LATE AUGUST WITH SNOW LEVELS
LOWERING TO BETWEEN 8K AND 9K FEET MONDAY NIGHT IN OUR CENTRAL AND
NRN MOUNTAINS. DRY WITH A WARMING TREND WEDNESDAY THROUGH THURSDAY
AS SHORTWAVE RIDGING MOVES IN. STILL BELOW NORMAL TEMPS WEDNESDAY
AND THEN BACK TO AROUND NORMAL BY THURSDAY.

&&

.AVIATION.../12Z ISSUANCE/
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL CONTINUE TO LIFT
NORTHEAST ACROSS THE NW HALF OF WYOMING INTO S CEN MT BY MIDDAY
TODAY. THIS SYSTEM WILL CONTINUE TO BRING SCT SHRA/ISOLD TSRA
MAINLY VCNTY AND NW OF A KEMM-KDUB-KBYG LINE. ACTIVITY WILL BE
MORE ISOLD SOUTH OF THIS LINE. LCL IFR/LIFR FG AND CIGS MAY
DEVELOP IN THE WESTERN VALLEYS THROUGH 15Z...MAINLY VCNTY KJAC-
KAFO. ISOLD-SCT TSRA WILL BLOSSOM IN THE SAME GENERAL AREA ACROSS
THE WEST AND NORTH THIS AFTERNOON. THE ATMOSPHERE WILL QUICKLY
STABILIZE FROM 0Z-3Z FRIDAY WITH MOST SHOWER AND THUNDERSTORM
ACTIVITY MOVING NE INTO MONTANA AND THE NORTHERN PLAINS. LCL
IFR/LIFR FOG MAY RE-DEVELOP IN THE FAR WEST VALLEYS AFTER 06Z
FRIDAY.

&&

.FIRE WEATHER...
SHOWERS WILL BE PREVALENT THIS MORNING WITH THUNDERSTORMS SHORT TO
FOLLOW THROUGH MID AFTERNOON,. THERE WILL BE A BREAK IN THE ACTION
LATER THIS AFTERNOON AND EVENING AS A SHORT LIVED HIGH PRESSURE
RIDGE BUILDS OVER THE AREA EXCEPT FOR NORTHWEST WYOMING WHERE
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. A POTENT
PACIFIC STORM SYSTEM WILL APPROACH THE AREA LATER TONIGHT WITH
NUMEROUS SHOWERS AND A FEW THUNDERSTORMS SPREADING FROM NORTHWEST
TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY AND INTO SATURDAY.
COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER SYSTEM WITH SNOW
LEVELS LOWERING TO 8000 FEET IN THE NORTHERN MOUNTAINS BY LATE
SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER ELEVATIONS BY SATURDAY
WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE GENERALLY LIGHT
EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS WELL AS DURING
THE COLD FRONTAL PASSAGE LATER THIS WEEK.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...TEAM RIVERTON
FIRE WEATHER...LIPSON











000
FXUS65 KRIW 210936
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
336 AM MDT THU AUG 21 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
SHOWERS AND A FEW THUNDERSTORMS CONTINUE TO ERUPT OVER EASTERN
IDAHO AS THE VORT LOBE OF THE NIGHT MOVES ON THROUGH CENTRAL WY
WITH THE NEXT VORT FOLLOWING CLOSE BEHIND OVER THE GREAT SALT
LAKE. AS A RESULT THERE WILL BE PLENTY OF RESIDUAL SHOWERS ACROSS
WESTERN AND NORTHERN WY THIS MORNING. THE LAST AFOREMENTIONED
SHORTWAVE WILL TRACK ACROSS WESTERN AND CENTRAL WYOMING TODAY FOR
AN EARLY SHOW OF CONVECTION BEFORE A TRANSITORY RIDGE BUILDS OVER
THE AREA LATER THIS AFTERNOON. AFTER 00Z FRIDAY... PRECIP WILL
DIMINISH AND WILL MAINLY BE LIMITED TO THE NORTHWEST. THEN AFTER
06Z FRIDAY...WIDESPREAD SHOWERS WILL DEVELOP OVER WESTERN WY AND
WILL SPREAD TOWARD CENTRAL WY AFTER 12Z FRIDAY ONCE THE NEGATIVELY
TILTED TROUGH OVER THE PAC NW CLOSES OFF OVER WASHINGTON AND
OREGON AND THE SOUTHWEST FLOW AHEAD OF THIS LOW INCREASES FROM THE
SOUTHWEST. FRIDAYS PRECIP WILL BE VERY DYNAMICALLY INDUCED ON A
SYNOPTIC SCALE...FIRST TIME IN A WHILE. QG FORCING IS PROGGED FOR
NW AND SOUTHERN WY FRIDAY WITH QG FORCING SPREADING TO NATRONA
COUNTY FRI NT. THE ASCT MID LEVEL CIRCULATION WILL TRACK TO IDAHO
FRIDAY NIGHT. SATURDAY LOOKS TO BE A COOL WET DAY AS THE MAIN LOW
APPROACHES THE NORTHERN ROCKIES. EXPECT LEFT FRONT QUAD DYNAMICS
OVER NW WY SATURDAY ONCE THE H5 LOW REACHES THE MT/ID BORDER ACDG
TO THE GFS WITH THE NAM A LITTLE FASTER TAKING IT TO CENTRAL MT.
ON SATURDAY THE MID LEVEL CIRCULATION IS PROGGED TO TRACK FROM YNP
TO AROUND HOT SPRINGS COUNTY AND THEN JOHNSON COUNTY BY SAT EVE.
TO THE NORTH OF THE H7 LOW OVER THE NORTHERN BORDER OF WY...EVEN
SOME WRAP AROUND ISENTROPIC LIFT IS EXPECTED. SFC CYCLOGENESIS IS
EXPECTED OVER SE WY. MOIST COOLER AIR WILL WRAP AROUND BEHIND
THESE CIRCULATIONS SATURDAY NIGHT AS A STRONG COLD FRONT MOVES
SOUTHEAST ACROSS WY. EXPECT NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS TO OVERSPREAD THE AREA FRIDAY NIGHT AND INTO
SATURDAY WITH THE INCREASING GRADIENT OF SHOWER ACTIVITY RUNNING
SOUTH TO NORTH AND THEN OVERSPREADING THE WHOLE STATE BY LATE
SATURDAY. AS THE SYSTEM GRADUALLY PULLS OUT OF THE AREA SATURDAY
NIGHT...H7 TEMPS WILL DROP TO -1C IN NW WY WHICH WILL BRING SNOW
LEVELS THERE FROM 10500 FEET SATURDAY MORNING TO 8000 FEET BY 12Z
SUNDAY. THE HIGHER PEAKS ELSEWHERE WILL ALSO SEE SNOW FROM ANY
LINGERING SHOWERS BY 12Z SUNDAY AS WELL. COULD SEE UP TO AN INCH
AND A HALF OF SNOWFALL IN THE BIG HORN MOUNTAINS BY EARLY SUNDAY
MORNING AND AN INCH IN THE ABSAROKAS. HIGH TEMPS IN MOST LOWER
ELEVATIONS SATURDAY WILL STRUGGLE TO GET ABOVE 70.

.LONG TERM...SUNDAY THROUGH THURSDAY
SATURDAY`S STORM SYSTEM WILL LIKELY BE OFF TO OUR EAST TO START THIS
PERIOD WITH JUST A LITTLE BIT OF MOISTURE AND INSTABILITY LEFT
BEHIND IN THE FAR NRN MOUNTAINS WHERE SOME SUNDAY SHOWERS/ISOLD
THUNDERSTORMS ARE EXPECTED. OTHERWISE...A COOL TO MILD DAY WITH
HIGHS ONLY IN THE 60S TO LOWER 70S WITH 50S AND SOME 60S IN THE HIGH
COUNTRY. THE NEXT MAJOR COOL TROUGH WHICH ORIGINATES FROM THE FAR
WRN ALEUTIAN LOW IS EXPECTED TO STRENGTHEN AS IT DROPS SE INTO THE
MEAN TROUGH. LEANING TOWARDS THE GFS/GEM IDEA AGAIN TONIGHT AND
NOT THE ECMWF WITH ITS DEVELOPING CUTOFF LOW OVER ERN CA AND NV ON
TUESDAY. THERE ARE A FEW GFS ENSEMBLE MEMBERS THAT ARE LEANING THAT WAY
BUT MOST KEEP THE TROUGH IN THE FLOW AND OVER THE ROCKIES REGION.
WORTH WATCHING BUT IT WOULD BE UNUSUAL TO SEE THAT STRONG OF A
CUTOFF LOW IN AUGUST THAT FAR SOUTH. SO GOING WITH THE GFS
IDEA...MAIN IMPACT DURING THE DAY MONDAY WITH CURRENT TIMING IS
THE NW AND POSSIBLY A SWATH IN THE FAR SERN ZONES BUT THEN MONDAY
NIGHT THE ASSOCIATED MID LEVEL CIRCULATION MAY MOVE RIGHT ACROSS
OUR FORECAST AREA BRINGING A GOOD CHANCE OF SHOWERS AND EMBEDDED
THUNDER MONDAY NIGHT AND TUESDAY MORNING IN OUR CENTRAL AND ERN
SECTIONS. A WARMER DAY EAST OF THE DIVIDE ON MONDAY ALONG WITH
INCREASING WIND AHEAD OF THIS SYSTEM. INLAND TRAJECTORY SHOULD
BRING DOWN SOME PRETTY COOL AIR FOR LATE AUGUST WITH SNOW LEVELS
LOWERING TO BETWEEN 8K AND 9K FEET MONDAY NIGHT IN OUR CENTRAL AND
NRN MOUNTAINS. DRY WITH A WARMING TREND WEDNESDAY THROUGH THURSDAY
AS SHORTWAVE RIDGING MOVES IN. STILL BELOW NORMAL TEMPS WEDNESDAY
AND THEN BACK TO AROUND NORMAL BY THURSDAY.

&&

.AVIATION.../12Z ISSUANCE/
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL CONTINUE TO LIFT
NORTHEAST ACROSS THE NW HALF OF WYOMING INTO S CEN MT BY MIDDAY
TODAY. THIS SYSTEM WILL CONTINUE TO BRING SCT SHRA/ISOLD TSRA
MAINLY VCNTY AND NW OF A KEMM-KDUB-KBYG LINE. ACTIVITY WILL BE
MORE ISOLD SOUTH OF THIS LINE. LCL IFR/LIFR FG AND CIGS MAY
DEVELOP IN THE WESTERN VALLEYS THROUGH 15Z...MAINLY VCNTY KJAC-
KAFO. ISOLD-SCT TSRA WILL BLOSSOM IN THE SAME GENERAL AREA ACROSS
THE WEST AND NORTH THIS AFTERNOON. THE ATMOSPHERE WILL QUICKLY
STABILIZE FROM 0Z-3Z FRIDAY WITH MOST SHOWER AND THUNDERSTORM
ACTIVITY MOVING NE INTO MONTANA AND THE NORTHERN PLAINS. LCL
IFR/LIFR FOG MAY RE-DEVELOP IN THE FAR WEST VALLEYS AFTER 06Z
FRIDAY.

&&

.FIRE WEATHER...
SHOWERS WILL BE PREVALENT THIS MORNING WITH THUNDERSTORMS SHORT TO
FOLLOW THROUGH MID AFTERNOON,. THERE WILL BE A BREAK IN THE ACTION
LATER THIS AFTERNOON AND EVENING AS A SHORT LIVED HIGH PRESSURE
RIDGE BUILDS OVER THE AREA EXCEPT FOR NORTHWEST WYOMING WHERE
SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE. A POTENT
PACIFIC STORM SYSTEM WILL APPROACH THE AREA LATER TONIGHT WITH
NUMEROUS SHOWERS AND A FEW THUNDERSTORMS SPREADING FROM NORTHWEST
TO SOUTHEAST LATER TONIGHT THROUGH FRIDAY AND INTO SATURDAY.
COOLER WEATHER WILL FILTER IN BEHIND THIS WEATHER SYSTEM WITH SNOW
LEVELS LOWERING TO 8000 FEET IN THE NORTHERN MOUNTAINS BY LATE
SATURDAY NIGHT. HIGH TEMPERATURES IN MOST LOWER ELEVATIONS BY SATURDAY
WILL STRUGGLE TO GET ABOVE 70. WINDS WILL BE GENERALLY LIGHT
EXCEPT FOR BRIEF GUSTY WINDS NEAR THUNDERSTORMS AS WELL AS DURING
THE COLD FRONTAL PASSAGE LATER THIS WEEK.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...TEAM RIVERTON
FIRE WEATHER...LIPSON












000
FXUS65 KRIW 210514
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1112 PM MDT WED AUG 20 2014

.SHORT TERM...TONIGHT THROUGH THURSDAY (ISSUED AT 208 PM MDT)

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES
EXTENDING SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE
EAST ACROSS MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE
WEST THROUGH THURSDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY
WILL ACCOMPANY THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS
WITH ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS. TEMPERATURES
WILL CONTINUE A GRADUAL COOLING TREND.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

SHOWERS AND STORMS CONTINUE INTO THURSDAY EVENING AS THE TROUGH
CONTINUES TO TREK EAST...SENDING OUT SHORT WAVES AS IT APPROACHES.
BY FRIDAY MORNING...THE MAIN TROUGH WILL CLOSE OFF OVER WASHINGTON
AND TRACK TO IDAHO BY FRIDAY NIGHT. THERE WILL BE PLENTY OF UPPER
LEVEL DYNAMICS WITH THE APPROACHING JET AND BROAD LIFT AHEAD OF
THE TROUGH TO ENHANCE SHOWER AND THUNDERSTORM COVERAGE...SO POPS
WERE BUMPED UP A BIT FOR FRIDAY...KEEPING WITH THE TREND FROM THE
PREVIOUS SHIFT.

ON SATURDAY...THE MAIN TROUGH MOVES INTO THE REGION...SENDING A
SIGNIFICANT COLD FRONT THROUGH THE FORECAST AREA WITH A GOOD CHANCE
OF SHOWERS AND SOME THUNDERSTORMS ALONG WITH SOME SNOW TO THE
HIGHER MOUNTAINS. THE MODELS HAVE YET TO AGREE ON EXACTLY HOW COLD
IT WILL BE BUT THE LATEST THINKING IS THAT SNOW LEVELS COULD DROP
TO 9KFT LATE SATURDAY NIGHT.

THE FLOW FLATTENS ON SUNDAY...TURNING DRIER AND MORE STABLE
HOWEVER ANOTHER TROUGH WILL BE APPROACHING THE REGION...WHICH
COULD BEGIN TO AFFECT THE FAR NORTHWEST BY THE EVENING...OTHERWISE
FLOW WILL SLOWLY TURN BACK TO THE SOUTHWEST. THERE COULD BE
ANOTHER ROUND OF SHOWERS...THUNDERSTORMS AND PERHAPS EVEN SOME
MORE HIGH ELEVATION SNOW MONDAY NIGHT INTO TUESDAY WITH MODELS
TRYING TO BUILD A RIDGE IN THEREAFTER...WHERE THE RIDGE IS
CENTERED REMAINS UNCERTAIN BUT THERE IS AGREEMENT IN A WARM UP BY
MID WEEK.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL CONTINUE TO LIFT
NORTHEAST ACROSS THE NW HALF OF WYOMING INTO S CEN MT BY MIDDAY
THURSDAY.  THIS SYSTEM WILL CONTINUE TO BRING SCT SHRA/ISOLD TSRA
MAINLY VCNTY AND NW OF A KEMM-KDUB-KBYG LINE.  ACTIVITY WILL BE MORE
ISOLD SOUTH OF THIS LINE.  LCL IFR/LIFR FG AND CIGS MAY DEVELOP IN
THE WESTERN VALLEYS THROUGH 15Z...MAINLY VCNTY KJAC-KAFO.  ISOLD-SCT
TSRA WILL BLOSSOM IN THE SAME GENERAL AREA ACROSS THE WEST AND NORTH
THURSDAY AFTERNOON.   THE ATMOSPHERE WILL QUICKLY STABILIZE FROM
0Z-3Z FRIDAY WITH MOST SHOWER AND THUNDERSTORM ACTIVITY MOVING NE
INTO MONTANA AND THE NORTHERN PLAINS.  LCL IFR/LIFR FOG MAY
RE-DEVELOP IN THE FAR WEST VALLEYS AFTER 06Z FRIDAY.

&&

.FIRE WEATHER...

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES
EXTENDING SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE
EAST ACROSS MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE
WEST THROUGH THURSDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY
WILL ACCOMPANY THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS.  TEMPERATURES WILL
CONTINUE A GRADUAL COOLING TREND WITH INCREASING RELATIVE HUMIDITY.
THERE WILL BE SUFFICIENT MOISTURE AVAILABLE TO KEEP MIXING HEIGHTS
SUPPRESSED...ESPECIALLY OVER THE WEST.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AEM
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 202008
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
208 PM MDT WED AUG 20 2014

.SHORT TERM...TONIGHT THROUGH THURSDAY

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES EXTENDING
SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE EAST ACROSS
MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE WEST THROUGH
THURSDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY WILL ACCOMPANY
THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WITH STRONG WIND GUSTS. TEMPERATURES WILL CONTINUE A
GRADUAL COOLING TREND.

.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY

SHOWERS AND STORMS CONTINUE INTO THURSDAY EVENING AS THE TROUGH
CONTINUES TO TREK EAST...SENDING OUT SHORT WAVES AS IT APPROACHES.
BY FRIDAY MORNING...THE MAIN TROUGH WILL CLOSE OFF OVER WASHINGTON
AND TRACK TO IDAHO BY FRIDAY NIGHT. THERE WILL BE PLENTY OF UPPER
LEVEL DYNAMICS WITH THE APPROACHING JET AND BROAD LIFT AHEAD OF
THE TROUGH TO ENHANCE SHOWER AND THUNDERSTORM COVERAGE...SO POPS
WERE BUMPED UP A BIT FOR FRIDAY...KEEPING WITH THE TREND FROM THE
PREVIOUS SHIFT.

ON SATURDAY...THE MAIN TROUGH MOVES INTO THE REGION...SENDING A
SIGNIFICANT COLD FRONT THROUGH THE FORECAST AREA WITH A GOOD CHANCE
OF SHOWERS AND SOME THUNDERSTORMS ALONG WITH SOME SNOW TO THE
HIGHER MOUNTAINS. THE MODELS HAVE YET TO AGREE ON EXACTLY HOW COLD
IT WILL BE BUT THE LATEST THINKING IS THAT SNOW LEVELS COULD DROP
TO 9KFT LATE SATURDAY NIGHT.

THE FLOW FLATTENS ON SUNDAY...TURNING DRIER AND MORE STABLE
HOWEVER ANOTHER TROUGH WILL BE APPROACHING THE REGION...WHICH
COULD BEGIN TO AFFECT THE FAR NORTHWEST BY THE EVENING...OTHERWISE
FLOW WILL SLOWLY TURN BACK TO THE SOUTHWEST. THERE COULD BE
ANOTHER ROUND OF SHOWERS...THUNDERSTORMS AND PERHAPS EVEN SOME
MORE HIGH ELEVATION SNOW MONDAY NIGHT INTO TUESDAY WITH MODELS
TRYING TO BUILD A RIDGE IN THEREAFTER...WHERE THE RIDGE IS
CENTERED REMAINS UNCERTAIN BUT THERE IS AGREEMENT IN A WARM UP BY
MID WEEK.

&&

.AVIATION.../00Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES
EXTENDING SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE EAST
ACROSS MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE WEST
THROUGH 00Z FRIDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY WILL
ACCOMPANY THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS. LOCAL IFR
CONDITIONS MAY PERSIST IN THE FAR WESTERN VALLEYS WHERE STRATUS
REMAINS TRAPPED IN JACKSON HOLE...YELLOWSTONE NATIONAL PARK AND
THE STAR VALLEY. THE SHOWERS AND THUNDERSTORMS WILL BE MOST
NUMEROUS THROUGH 06Z THURSDAY WITH LOCAL MOUNTAIN OBSCURATIONS
EXPECTED.

SOME SHOWERS AND POSSIBLE THUNDERSTORMS WILL LINGER THROUGH THE
NIGHT AND THURSDAY MORNING...ESPECIALLY OVER THE WESTERN
MOUNTAINS. THEN SHOWERS AND ISOLATED THUNDERSTORMS WILL AGAIN BECOME
MORE NUMEROUS BETWEEN 18Z THURSDAY AND 00Z FRIDAY WITH LOCAL MOUNTAIN
OBSCURATIONS.

&&

.FIRE WEATHER...

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES
EXTENDING SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE EAST
ACROSS MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE WEST
THROUGH THURSDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY WILL
ACCOMPANY THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS.  TEMPERATURES WILL
CONTINUE A GRADUAL COOLING TREND WITH INCREASING RELATIVE
HUMIDITY. THERE WILL BE SUFFICIENT MOISTURE AVAILABLE TO KEEP
MIXING HEIGHTS SUPPRESSED...ESPECIALLY OVER THE WEST.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








000
FXUS65 KRIW 201649
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1049 AM MDT WED AUG 20 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT

THE MID LEVEL CIRCULATION ASCT WITH THE SHORTWAVE TROUGH...WHICH
IS TRACKING EAST ACROSS WESTERN WY...APPEARS TO BE OVER THE RED
DESERT ALONG THE BACK EDGE OF THE WIDESPREAD AREA OF PATCHY LIGHT
RAIN EXTENDING FROM CODY TO RIW TO RKS THAT USED TO BE CONVECTIVE
ACTIVITY OVER IDAHO BEFORE THE PRECIP MOVED INTO MORE STABLE AIR
OVER WY. THE DRY SLOT WILL MOVE NORTHEAST INTO CENTRAL WY AND INTO
JOHNSON COUNTY ALONG WITH THE MID LEVEL CIRCULATION BY 12Z THIS
MORNING. ADDITIONAL RAIN SHOWERS WILL LINGER IN THE MOUNTAINS
LATER INTO THE MORNING AS THE BACK EDGE OF THE SHORTWAVE TROUGH
CLEARS THROUGH. THEN BEHIND THIS AREA OF EXITING
CLOUDINESS...CONVECTION WILL FIRE RAPIDLY ACROSS WESTERN WY WITHIN
THE DIFLUENT WEST SOUTHWESTERLY FLOW AHEAD OF THE NEXT APPROACHING
VORT LOBE ROTATING AROUND THE BASE OF THE MAIN TROUGH OVER
SOUTHWEST CANADA WHERE THE BEST CAPES WILL BE. NUMEROUS TO SCT
SHOWERS AND THUNDERSTORMS ARE EXPECTED IN WESTERN WY WITH MAINLY
SCT EAST. TOTAL TOTALS WILL BE FAVORABLE FOR WIDESPREAD
CONVECTION. THEN ON THURSDAY ANOTHER VORT LOBE WILL ROTATE AROUND
THIS TROUGH FOR MORE CONVECTION MAINLY IN THE NORTH AND WEST. THEN
ON FRIDAY MORNING...THE MAIN TROUGH WILL CLOSE OFF OVER WASHINGTON
AND TRACK TO IDAHO BY FRIDAY NIGHT. THE GFS HAS COME MORE INTO
LINE WITH THE FASTER ECMWF WITH THIS SOLN. AS THE
DYNAMICS...INCLUDING LEFT FRONT QUAD JET DYNAMICS...AND INCREASING
SOUTHWEST DIFLUENT FLOW INCREASE WITH THIS APPROACHING LOW...WITH
ITS ASCT WEAK H7 CIRCULATION APPROACHING NW WY...SHOWERS AND
THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AND FRIDAY NIGHT
ALONG WITH COOLER TEMPS AS A RESULT OF THE ADDED CLOUDS AND
PRECIP. A SFC LOW WILL TRACK ACROSS CASPER ASCT WITH THE SOUTHERN
STREAM H5 LOW THAT THE GFS HAS OVER CO ADDING TO THE DYNAMICS AND
PULLING SOME COOLER AIR BEHIND IT FRIDAY EVE. THE ECMWF HAS THE H5
LOW OVER AZ DURING THIS TIME. COOLER AIR WILL FILTER INTO THE
NORTHWEST PORTION OF WY FRI NT AS THE MAIN PAC NW WEATHER SYSTEM
NEARS WITH H7 TEMPS EXPECTING TO DROP TO 2.2C BY 12Z SAT OVER NW
WY WHERE SNOW LEVELS COULD DROP TO 9500 FEET.

.LONG TERM...SATURDAY THROUGH WEDNESDAY

SIGNIFICANT COOL LATE AUGUST TROUGH IS EXPECTED TO SWING ACROSS
THE AREA ON SATURDAY WITH A GOOD CHANCE OF SHOWERS AND SOME
THUNDERSTORMS ALONG WITH SKIFF OF SNOW TO THE HIGHER MOUNTAINS.
SNOW LEVELS WHICH SHOULD BE ABOVE 10-11K FEET DURING THE DAY
SATURDAY WILL LOWER SATURDAY EVENING TO AS LOW AS 8.5-9K FEET
IN THE FAR NRN MOUNTAINS. SUNDAY WILL BE DRIER AND MORE STABLE
EXCEPT IN THE NW WHERE NEXT APPROACHING TROUGH IS ALREADY
SPREADING SOME MOISTURE AND FORCING INTO THE AREA. NEXT COOL
TROUGH WILL BRING IN ANOTHER ROUND OF SHOWERS AND SOME
THUNDERSTORMS MONDAY INTO TUESDAY FOR MANY AREAS...ESPECIALLY
THE MOUNTAINS...NORTH HALF AND THE SERN CORNER. ANOTHER COUPLE
UNSEASONABLY COOL DAYS WITH THIS TROUGH AS H7 TEMPERATURES DROP
WELL DOWN INTO THE SINGLE DIGITS. ANOTHER SKIFF OR MORE OF
MOUNTAIN SNOW IS VERY POSSIBLE AGAIN ABOVE 10-11K MONDAY THROUGH
TUESDAY AT TIMES. ECMWF HAS MORE RIDGING BY WEDNESDAY WHILE THE
GFS IS STILL SHOWING A MORE MOIST NW FLOW. WILL KEEP IT FAIRLY DRY
FOR NOW WITH ONLY A HINT OF HIGHER MOUNTAIN SHOWERS IN THE NRN
MOUNTAINS.

.AVIATION.../18Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES
EXTENDING SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE EAST
ACROSS MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE WEST
THROUGH 18Z THURSDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY
WILL ACCOMPANY THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS. LOCAL IFR
CONDITIONS MAY PERSIST IN THE FAR WESTERN VALLEYS WHERE STRATUS
REMAINS TRAPPED IN JACKSON HOLE...YELLOWSTONE NATIONAL PARK AND THE
STAR VALLEY. THE SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS
THROUGH 06Z THURSDAY WITH LOCAL MOUNTAIN OBSCURATIONS EXPECTED.

SOME SHOWERS AND POSSIBLE THUNDERSTORMS WILL LINGER THROUGH THE
NIGHT AND THURSDAY MORNING...ESPECIALLY OVER THE WESTERN
MOUNTAINS.


.FIRE WEATHER...

WAVES OF ENERGY COMING OFF THE PACIFIC BISECTING MONSOON ENERGY
WILL KEEP A GOOD CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
GOING ALL WEEK. MIN RH WILL GENERALLY RUN IN THE 20S AT THE LOWER
ELEVATIONS
..EXCEPT 30S IN THE WESTERN VALLEYS...THROUGH THURSDAY BEFORE INCREASING.
A COOLER PACIFIC WEATHER SYSTEM WILL BRING MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY WITH COOLER AIR
FILTERING IN. THE SNOW LEVEL SHOULD LOWER TO 9500 FEET OR SO BY
SATURDAY MORNING IN ZONE 140.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...C.BAKER
FIRE WEATHER...LIPSON







000
FXUS65 KRIW 201649
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1049 AM MDT WED AUG 20 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT

THE MID LEVEL CIRCULATION ASCT WITH THE SHORTWAVE TROUGH...WHICH
IS TRACKING EAST ACROSS WESTERN WY...APPEARS TO BE OVER THE RED
DESERT ALONG THE BACK EDGE OF THE WIDESPREAD AREA OF PATCHY LIGHT
RAIN EXTENDING FROM CODY TO RIW TO RKS THAT USED TO BE CONVECTIVE
ACTIVITY OVER IDAHO BEFORE THE PRECIP MOVED INTO MORE STABLE AIR
OVER WY. THE DRY SLOT WILL MOVE NORTHEAST INTO CENTRAL WY AND INTO
JOHNSON COUNTY ALONG WITH THE MID LEVEL CIRCULATION BY 12Z THIS
MORNING. ADDITIONAL RAIN SHOWERS WILL LINGER IN THE MOUNTAINS
LATER INTO THE MORNING AS THE BACK EDGE OF THE SHORTWAVE TROUGH
CLEARS THROUGH. THEN BEHIND THIS AREA OF EXITING
CLOUDINESS...CONVECTION WILL FIRE RAPIDLY ACROSS WESTERN WY WITHIN
THE DIFLUENT WEST SOUTHWESTERLY FLOW AHEAD OF THE NEXT APPROACHING
VORT LOBE ROTATING AROUND THE BASE OF THE MAIN TROUGH OVER
SOUTHWEST CANADA WHERE THE BEST CAPES WILL BE. NUMEROUS TO SCT
SHOWERS AND THUNDERSTORMS ARE EXPECTED IN WESTERN WY WITH MAINLY
SCT EAST. TOTAL TOTALS WILL BE FAVORABLE FOR WIDESPREAD
CONVECTION. THEN ON THURSDAY ANOTHER VORT LOBE WILL ROTATE AROUND
THIS TROUGH FOR MORE CONVECTION MAINLY IN THE NORTH AND WEST. THEN
ON FRIDAY MORNING...THE MAIN TROUGH WILL CLOSE OFF OVER WASHINGTON
AND TRACK TO IDAHO BY FRIDAY NIGHT. THE GFS HAS COME MORE INTO
LINE WITH THE FASTER ECMWF WITH THIS SOLN. AS THE
DYNAMICS...INCLUDING LEFT FRONT QUAD JET DYNAMICS...AND INCREASING
SOUTHWEST DIFLUENT FLOW INCREASE WITH THIS APPROACHING LOW...WITH
ITS ASCT WEAK H7 CIRCULATION APPROACHING NW WY...SHOWERS AND
THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AND FRIDAY NIGHT
ALONG WITH COOLER TEMPS AS A RESULT OF THE ADDED CLOUDS AND
PRECIP. A SFC LOW WILL TRACK ACROSS CASPER ASCT WITH THE SOUTHERN
STREAM H5 LOW THAT THE GFS HAS OVER CO ADDING TO THE DYNAMICS AND
PULLING SOME COOLER AIR BEHIND IT FRIDAY EVE. THE ECMWF HAS THE H5
LOW OVER AZ DURING THIS TIME. COOLER AIR WILL FILTER INTO THE
NORTHWEST PORTION OF WY FRI NT AS THE MAIN PAC NW WEATHER SYSTEM
NEARS WITH H7 TEMPS EXPECTING TO DROP TO 2.2C BY 12Z SAT OVER NW
WY WHERE SNOW LEVELS COULD DROP TO 9500 FEET.

.LONG TERM...SATURDAY THROUGH WEDNESDAY

SIGNIFICANT COOL LATE AUGUST TROUGH IS EXPECTED TO SWING ACROSS
THE AREA ON SATURDAY WITH A GOOD CHANCE OF SHOWERS AND SOME
THUNDERSTORMS ALONG WITH SKIFF OF SNOW TO THE HIGHER MOUNTAINS.
SNOW LEVELS WHICH SHOULD BE ABOVE 10-11K FEET DURING THE DAY
SATURDAY WILL LOWER SATURDAY EVENING TO AS LOW AS 8.5-9K FEET
IN THE FAR NRN MOUNTAINS. SUNDAY WILL BE DRIER AND MORE STABLE
EXCEPT IN THE NW WHERE NEXT APPROACHING TROUGH IS ALREADY
SPREADING SOME MOISTURE AND FORCING INTO THE AREA. NEXT COOL
TROUGH WILL BRING IN ANOTHER ROUND OF SHOWERS AND SOME
THUNDERSTORMS MONDAY INTO TUESDAY FOR MANY AREAS...ESPECIALLY
THE MOUNTAINS...NORTH HALF AND THE SERN CORNER. ANOTHER COUPLE
UNSEASONABLY COOL DAYS WITH THIS TROUGH AS H7 TEMPERATURES DROP
WELL DOWN INTO THE SINGLE DIGITS. ANOTHER SKIFF OR MORE OF
MOUNTAIN SNOW IS VERY POSSIBLE AGAIN ABOVE 10-11K MONDAY THROUGH
TUESDAY AT TIMES. ECMWF HAS MORE RIDGING BY WEDNESDAY WHILE THE
GFS IS STILL SHOWING A MORE MOIST NW FLOW. WILL KEEP IT FAIRLY DRY
FOR NOW WITH ONLY A HINT OF HIGHER MOUNTAIN SHOWERS IN THE NRN
MOUNTAINS.

.AVIATION.../18Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE TROUGH OVER THE NORTHERN ROCKIES
EXTENDING SOUTH INTO THE NORTHERN GREAT BASIN WILL PARTIALLY MOVE EAST
ACROSS MONTANA AND WYOMING WITH REFORMATION OCCURRING TO THE WEST
THROUGH 18Z THURSDAY. SUFFICIENT MOISTURE...SHEAR AND INSTABILITY
WILL ACCOMPANY THE TROUGH AS IT MOVES EAST FOR SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS WITH STRONG WIND GUSTS. LOCAL IFR
CONDITIONS MAY PERSIST IN THE FAR WESTERN VALLEYS WHERE STRATUS
REMAINS TRAPPED IN JACKSON HOLE...YELLOWSTONE NATIONAL PARK AND THE
STAR VALLEY. THE SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS
THROUGH 06Z THURSDAY WITH LOCAL MOUNTAIN OBSCURATIONS EXPECTED.

SOME SHOWERS AND POSSIBLE THUNDERSTORMS WILL LINGER THROUGH THE
NIGHT AND THURSDAY MORNING...ESPECIALLY OVER THE WESTERN
MOUNTAINS.


.FIRE WEATHER...

WAVES OF ENERGY COMING OFF THE PACIFIC BISECTING MONSOON ENERGY
WILL KEEP A GOOD CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
GOING ALL WEEK. MIN RH WILL GENERALLY RUN IN THE 20S AT THE LOWER
ELEVATIONS
..EXCEPT 30S IN THE WESTERN VALLEYS...THROUGH THURSDAY BEFORE INCREASING.
A COOLER PACIFIC WEATHER SYSTEM WILL BRING MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY WITH COOLER AIR
FILTERING IN. THE SNOW LEVEL SHOULD LOWER TO 9500 FEET OR SO BY
SATURDAY MORNING IN ZONE 140.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...C.BAKER
FIRE WEATHER...LIPSON








000
FXUS65 KRIW 200923
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
323 AM MDT WED AUG 20 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
THE MID LEVEL CIRCULATION ASCT WITH THE SHORTWAVE TROUGH...WHICH IS
TRACKING EAST ACROSS WESTERN WY...APPEARS TO BE OVER THE RED DESERT
ALONG THE BACK EDGE OF THE WIDESPREAD AREA OF PATCHY LIGHT RAIN
EXTENDING FROM CODY TO RIW TO RKS THAT USED TO BE CONVECTIVE
ACTIVITY OVER IDAHO BEFORE THE PRECIP MOVED INTO MORE STABLE AIR
OVER WY. THE DRY SLOT WILL MOVE NORTHEAST INTO CENTRAL WY AND INTO
JOHNSON COUNTY ALONG WITH THE MID LEVEL CIRCULATION BY 12Z THIS
MORNING. ADDITIONAL RAIN SHOWERS WILL LINGER IN THE MOUNTAINS LATER
INTO THE MORNING AS THE BACK EDGE OF THE SHORTWAVE TROUGH CLEARS
THROUGH. THEN BEHIND THIS AREA OF EXITING CLOUDINESS...CONVECTION
WILL FIRE RAPIDLY ACROSS WESTERN WY WITHIN THE DIFLUENT WEST
SOUTHWESTERLY FLOW AHEAD OF THE NEXT APPROACHING VORT LOBE ROTATING
AROUND THE BASE OF THE MAIN TROUGH OVER SOUTHWEST CANADA WHERE THE
BEST CAPES WILL BE. NUMEROUS TO SCT SHOWERS AND THUNDERSTORMS ARE
EXPECTED IN WESTERN WY WITH MAINLY SCT EAST. TOTAL TOTALS WILL BE
FAVORABLE FOR WIDESPREAD CONVECTION. THEN ON THURSDAY ANOTHER VORT
LOBE WILL ROTATE AROUND THIS TROUGH FOR MORE CONVECTION MAINLY IN
THE NORTH AND WEST. THEN ON FRIDAY MORNING...THE MAIN TROUGH WILL
CLOSE OFF OVER WASHINGTON AND TRACK TO IDAHO BY FRIDAY NIGHT. THE
GFS HAS COME MORE INTO LINE WITH THE FASTER ECMWF WITH THIS SOLN. AS
THE DYNAMICS...INCLUDING LEFT FRONT QUAD JET DYNAMICS...AND
INCREASING SOUTHWEST DIFLUENT FLOW INCREASE WITH THIS APPROACHING
LOW...WITH ITS ASCT WEAK H7 CIRCULATION APPROACHING NW WY...SHOWERS
AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AND FRIDAY
NIGHT ALONG WITH COOLER TEMPS AS A RESULT OF THE ADDED CLOUDS AND
PRECIP. A SFC LOW WILL TRACK ACROSS CASPER ASCT WITH THE SOUTHERN
STREAM H5 LOW THAT THE GFS HAS OVER CO ADDING TO THE DYNAMICS AND
PULLING SOME COOLER AIR BEHIND IT FRIDAY EVE. THE ECMWF HAS THE H5
LOW OVER AZ DURING THIS TIME. COOLER AIR WILL FILTER INTO THE
NORTHWEST PORTION OF WY FRI NT AS THE MAIN PAC NW WEATHER SYSTEM
NEARS WITH H7 TEMPS EXPECTING TO DROP TO 2.2C BY 12Z SAT OVER NW WY
WHERE SNOW LEVELS COULD DROP TO 9500 FEET.

.LONG TERM...SATURDAY THROUGH WEDNESDAY
SIGNIFICANT COOL LATE AUGUST TROUGH IS EXPECTED TO SWING ACROSS
THE AREA ON SATURDAY WITH A GOOD CHANCE OF SHOWERS AND SOME
THUNDERSTORMS ALONG WITH SKIFF OF SNOW TO THE HIGHER MOUNTAINS.
SNOW LEVELS WHICH SHOULD BE ABOVE 10-11K FEET DURING THE DAY
SATURDAY WILL LOWER SATURDAY EVENING TO AS LOW AS 8.5-9K FEET
IN THE FAR NRN MOUNTAINS. SUNDAY WILL BE DRIER AND MORE STABLE
EXCEPT IN THE NW WHERE NEXT APPROACHING TROUGH IS ALREADY
SPREADING SOME MOISTURE AND FORCING INTO THE AREA. NEXT COOL
TROUGH WILL BRING IN ANOTHER ROUND OF SHOWERS AND SOME
THUNDERSTORMS MONDAY INTO TUESDAY FOR MANY AREAS...ESPECIALLY
THE MOUNTAINS...NORTH HALF AND THE SERN CORNER. ANOTHER COUPLE
UNSEASONABLY COOL DAYS WITH THIS TROUGH AS H7 TEMPERATURES DROP
WELL DOWN INTO THE SINGLE DIGITS. ANOTHER SKIFF OR MORE OF
MOUNTAIN SNOW IS VERY POSSIBLE AGAIN ABOVE 10-11K MONDAY THROUGH
TUESDAY AT TIMES. ECMWF HAS MORE RIDGING BY WEDNESDAY WHILE THE
GFS IS STILL SHOWING A MORE MOIST NW FLOW. WILL KEEP IT FAIRLY DRY
FOR NOW WITH ONLY A HINT OF HIGHER MOUNTAIN SHOWERS IN THE NRN
MOUNTAINS.

&&

.AVIATION.../12Z ISSUANCE/
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL LIFT INTO EASTERN MONTANA
THIS MORNING WITH SHOWER ACTIVITY DECREASING ACROSS NORTHERN WYOMING
12Z-15Z.   AN UPPER TROUGH OVER THE NW U.S. WILL EJECT THE NEXT
DISTURBANCE ACROSS IDAHO THIS AFTERNOON AND ACROSS NORTHERN WYOMING
TONIGHT.  EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO SPREAD INTO
WESTERN WYOMING THROUGH THE AFTERNOON WITH THE BETTER COVERAGE VCNTY
AND NORTH OF A KJAC-KDUB LINE.  THIS ACTIVITY WILL SPREAD INTO NORTH
CENTRAL WYOMING THROUGH THE LATE AFTERNOON AND EVENING.  SHOWER AND
THUNDERSTORM ACTIVITY WILL BE MUCH MORE ISOLATED ACROSS CENTRAL
WYOMING WED AFTN/EVE...VCNTY KLND-KRIW-KCPR.

&&

.FIRE WEATHER...
WAVES OF ENERGY COMING OFF THE PACIFIC BISECTING MONSOON ENERGY WILL
KEEP A GOOD CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS GOING ALL
WEEK. MIN RH WILL GENERALLY RUN IN THE 20S AT THE LOWER ELEVATIONS
...EXCEPT 30S IN THE WESTERN VALLEYS...THROUGH THURSDAY BEFORE INCREASING.
A COOLER PACIFIC WEATHER SYSTEM WILL BRING MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY WITH COOLER AIR
FILTERING IN. THE SNOW LEVEL SHOULD LOWER TO 9500 FEET OR SO BY
SATURDAY MORNING IN ZONE 140.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...AEM
FIRE WEATHER...LIPSON










000
FXUS65 KRIW 200923
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
323 AM MDT WED AUG 20 2014

.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
THE MID LEVEL CIRCULATION ASCT WITH THE SHORTWAVE TROUGH...WHICH IS
TRACKING EAST ACROSS WESTERN WY...APPEARS TO BE OVER THE RED DESERT
ALONG THE BACK EDGE OF THE WIDESPREAD AREA OF PATCHY LIGHT RAIN
EXTENDING FROM CODY TO RIW TO RKS THAT USED TO BE CONVECTIVE
ACTIVITY OVER IDAHO BEFORE THE PRECIP MOVED INTO MORE STABLE AIR
OVER WY. THE DRY SLOT WILL MOVE NORTHEAST INTO CENTRAL WY AND INTO
JOHNSON COUNTY ALONG WITH THE MID LEVEL CIRCULATION BY 12Z THIS
MORNING. ADDITIONAL RAIN SHOWERS WILL LINGER IN THE MOUNTAINS LATER
INTO THE MORNING AS THE BACK EDGE OF THE SHORTWAVE TROUGH CLEARS
THROUGH. THEN BEHIND THIS AREA OF EXITING CLOUDINESS...CONVECTION
WILL FIRE RAPIDLY ACROSS WESTERN WY WITHIN THE DIFLUENT WEST
SOUTHWESTERLY FLOW AHEAD OF THE NEXT APPROACHING VORT LOBE ROTATING
AROUND THE BASE OF THE MAIN TROUGH OVER SOUTHWEST CANADA WHERE THE
BEST CAPES WILL BE. NUMEROUS TO SCT SHOWERS AND THUNDERSTORMS ARE
EXPECTED IN WESTERN WY WITH MAINLY SCT EAST. TOTAL TOTALS WILL BE
FAVORABLE FOR WIDESPREAD CONVECTION. THEN ON THURSDAY ANOTHER VORT
LOBE WILL ROTATE AROUND THIS TROUGH FOR MORE CONVECTION MAINLY IN
THE NORTH AND WEST. THEN ON FRIDAY MORNING...THE MAIN TROUGH WILL
CLOSE OFF OVER WASHINGTON AND TRACK TO IDAHO BY FRIDAY NIGHT. THE
GFS HAS COME MORE INTO LINE WITH THE FASTER ECMWF WITH THIS SOLN. AS
THE DYNAMICS...INCLUDING LEFT FRONT QUAD JET DYNAMICS...AND
INCREASING SOUTHWEST DIFLUENT FLOW INCREASE WITH THIS APPROACHING
LOW...WITH ITS ASCT WEAK H7 CIRCULATION APPROACHING NW WY...SHOWERS
AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD FRIDAY AND FRIDAY
NIGHT ALONG WITH COOLER TEMPS AS A RESULT OF THE ADDED CLOUDS AND
PRECIP. A SFC LOW WILL TRACK ACROSS CASPER ASCT WITH THE SOUTHERN
STREAM H5 LOW THAT THE GFS HAS OVER CO ADDING TO THE DYNAMICS AND
PULLING SOME COOLER AIR BEHIND IT FRIDAY EVE. THE ECMWF HAS THE H5
LOW OVER AZ DURING THIS TIME. COOLER AIR WILL FILTER INTO THE
NORTHWEST PORTION OF WY FRI NT AS THE MAIN PAC NW WEATHER SYSTEM
NEARS WITH H7 TEMPS EXPECTING TO DROP TO 2.2C BY 12Z SAT OVER NW WY
WHERE SNOW LEVELS COULD DROP TO 9500 FEET.

.LONG TERM...SATURDAY THROUGH WEDNESDAY
SIGNIFICANT COOL LATE AUGUST TROUGH IS EXPECTED TO SWING ACROSS
THE AREA ON SATURDAY WITH A GOOD CHANCE OF SHOWERS AND SOME
THUNDERSTORMS ALONG WITH SKIFF OF SNOW TO THE HIGHER MOUNTAINS.
SNOW LEVELS WHICH SHOULD BE ABOVE 10-11K FEET DURING THE DAY
SATURDAY WILL LOWER SATURDAY EVENING TO AS LOW AS 8.5-9K FEET
IN THE FAR NRN MOUNTAINS. SUNDAY WILL BE DRIER AND MORE STABLE
EXCEPT IN THE NW WHERE NEXT APPROACHING TROUGH IS ALREADY
SPREADING SOME MOISTURE AND FORCING INTO THE AREA. NEXT COOL
TROUGH WILL BRING IN ANOTHER ROUND OF SHOWERS AND SOME
THUNDERSTORMS MONDAY INTO TUESDAY FOR MANY AREAS...ESPECIALLY
THE MOUNTAINS...NORTH HALF AND THE SERN CORNER. ANOTHER COUPLE
UNSEASONABLY COOL DAYS WITH THIS TROUGH AS H7 TEMPERATURES DROP
WELL DOWN INTO THE SINGLE DIGITS. ANOTHER SKIFF OR MORE OF
MOUNTAIN SNOW IS VERY POSSIBLE AGAIN ABOVE 10-11K MONDAY THROUGH
TUESDAY AT TIMES. ECMWF HAS MORE RIDGING BY WEDNESDAY WHILE THE
GFS IS STILL SHOWING A MORE MOIST NW FLOW. WILL KEEP IT FAIRLY DRY
FOR NOW WITH ONLY A HINT OF HIGHER MOUNTAIN SHOWERS IN THE NRN
MOUNTAINS.

&&

.AVIATION.../12Z ISSUANCE/
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL LIFT INTO EASTERN MONTANA
THIS MORNING WITH SHOWER ACTIVITY DECREASING ACROSS NORTHERN WYOMING
12Z-15Z.   AN UPPER TROUGH OVER THE NW U.S. WILL EJECT THE NEXT
DISTURBANCE ACROSS IDAHO THIS AFTERNOON AND ACROSS NORTHERN WYOMING
TONIGHT.  EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO SPREAD INTO
WESTERN WYOMING THROUGH THE AFTERNOON WITH THE BETTER COVERAGE VCNTY
AND NORTH OF A KJAC-KDUB LINE.  THIS ACTIVITY WILL SPREAD INTO NORTH
CENTRAL WYOMING THROUGH THE LATE AFTERNOON AND EVENING.  SHOWER AND
THUNDERSTORM ACTIVITY WILL BE MUCH MORE ISOLATED ACROSS CENTRAL
WYOMING WED AFTN/EVE...VCNTY KLND-KRIW-KCPR.

&&

.FIRE WEATHER...
WAVES OF ENERGY COMING OFF THE PACIFIC BISECTING MONSOON ENERGY WILL
KEEP A GOOD CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS GOING ALL
WEEK. MIN RH WILL GENERALLY RUN IN THE 20S AT THE LOWER ELEVATIONS
...EXCEPT 30S IN THE WESTERN VALLEYS...THROUGH THURSDAY BEFORE INCREASING.
A COOLER PACIFIC WEATHER SYSTEM WILL BRING MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY WITH COOLER AIR
FILTERING IN. THE SNOW LEVEL SHOULD LOWER TO 9500 FEET OR SO BY
SATURDAY MORNING IN ZONE 140.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...SKRBAC
AVIATION...AEM
FIRE WEATHER...LIPSON









000
FXUS65 KRIW 200547
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1147 PM MDT TUE AUG 19 2014


.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 221 PM MDT)

TONIGHT WE WILL TRANSITION TO MORE OF A WIDESPREAD SHOWER/ISOLATED
THUNDERSTORM WITH HEAVY RAIN SCENARIO AS THE RICH MOISTURE IS
STIRRED UP BY SOME PVA AND DECENT QG FORCING THROUGH ABOUT 06Z.
THERE WILL BE SOME FLASH FLOOD POTENTIAL...ESPECIALLY EARLY WITH
HEAVIER STORMS AND OVR HIGHER TERRAIN OVERNIGHT WHERE TERRAIN FORCED
RAINFALL WITH CONVECTIVE ELEMENTS COINCIDE...ESPECIALLY ON S TO SW
FACING SLOPES OVERNIGHT AND THRU WED MORNING. LIKED THE OVERNIGHT
SHIFT THINKING WITH AVOIDING A FLASH FLOOD WATCH...SINCE THIS EVENT
WILL BE PARTIALLY CONVECTIVE...THEN STRATIFORM LATER
TONIGHT...CHOOSING TO WAIT AND SEE HOW ALL THIS EVOLVES.
HOWEVER...LATER DURING THIS FCST PERIOD...A FFW MAY BE NECESSARY
ACROSS SOME OF THE WRN MOUNTAIN ZONES AS THE GROUND SATURATES AND
PRECIPITATION KEEPS FALLING THROUGH AT LEAST THURSDAY.

WEDNESDAY AND THURSDAY...ABUNDANT MOISTURE REMAINS IN THE REGION BUT
THE UPPER LEVEL FORCING LEAVES FOR WEDNESDAY...EXPECT MORE OF AN
AIRMASS/DIURNAL THUNDERSTORM SETUP. THERE HAVE BEEN SOME MODEL
UNCERTAINTIES AS TO WHAT WILL ARRIVE ON THURSDAY...BUT THERE MAY BE
SOME MORE BROAD LIFT ARRIVING WITH ANOTHER SHORT WAVE QUICKLY
FOLLOWED BY A LONG WAVE TROUGH ACROSS THE GREAT BASIN TAKING ON A
NEGATIVE TILT AND MOVING OUR DIRECTION...IF THIS SHOULD HAPPEN THEN
SOME MORE ORGANIZED THUNDERSTORM ACTIVITY COULD VISIT THE FORECAST
AREA BUT HAVE KEPT A HEALTHY DOSE OF UNCERTAINTY IN THE GRIDS AT
THIS TIME. IN ANY EVENT...IT IS LIKELY THAT MUCH OF THE FORECAST
AREA WILL CONTINUE TO SEE BOUTS OF HEAVY RAIN THROUGH THURSDAY AND
PERHAPS EVEN FRIDAY...ESPECIALLY ACROSS THE WESTERN
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY

MEDIUM-RANGE MODEL SOLUTIONS ARE IN FAIR AGREEMENT TODAY. BROAD
TROUGH ACROSS THE NORTHWEST U.S. TO BEGIN THE FORECAST PERIOD WITH
HIGH PRESSURE OVER THE SOUTHERN U.S. HELPING TO SLOW THE EASTWARD
PROGRESSION OF THE TROUGH. MODELS HAVE SLOWED SOME FROM MONDAY RUNS
REGARDING THE UPCOMING WEEKEND WEATHER SYSTEM. OVERALL...COOLER
PATTERN TO BE IN PLACE ACROSS THE ROCKIES THROUGH THE PERIOD.

LONG WAVE TROUGH WILL BE POSITIONED OVER THE INTERMOUNTAIN WEST AND
PACIFIC NORTHWEST TO BEGIN THE PERIOD. WEAK SHORTWAVE ENERGY IS
LIKELY TO BE EJECTED EASTWARD ACROSS WYOMING FRIDAY NIGHT AND FAVOR
PRECIPITATION IN THE NORTHWEST AND NORTHERN MOUNTAINS. HAVE NUDGED
PRECIP CHANCES UPWARD IN THESE TWO LOCATIONS. THIS SCENARIO IS
LIKELY TO PLAY OUT THROUGH SATURDAY AS THE TROUGH NEARS WYOMING AND
SOUTHWEST FLOW ALOFT REMAINS OVER THE FORECAST AREA. SOME ADDITIONAL
SUB-TROPICAL MOISTURE WILL BE DRAWN NORTH INTO WYOMING SATURDAY
AFTERNOON AND EVENING. HAVE INCREASED PRECIP CHANCES EAST OF THE
DIVIDE TO ACCOUNT FOR THIS. IF MODELS CONTINUE TO COME MORE IN-LINE
IT IS LIKELY THAT PRECIP CHANCES WOULD NEED TO BE BUMPED UP AND
EXPANDED WEST SATURDAY AFTERNOON AND EVENING. MID-LEVEL CIRCULATION
WILL MOVE ALONG OUR NORTHERN BORDER SATURDAY NIGHT KEEPING SHOWERS
GOING ALL NIGHT ACROSS THE NORTH. THIS CIRCULATION WILL SWING TO OUR
EAST BY MIDDAY SUNDAY SUBSEQUENTLY DRAWING COOLER AIR SOUTH ACROSS
WYOMING IN CYCLONIC FLOW. FAVORABLE WEST-NORTHWEST FLOW SHOULD KEEP
THE BIGHORNS AND PORTIONS OF THE NORTHWEST MOUNTAINS WET SUNDAY
AFTERNOON/NIGHT. ELSEWHERE...THE SOUTHWEST LOOKS TO BE THE DRIEST
AREA SUNDAY AND SUNDAY NIGHT AS THE UPPER FLOW BACKS TO THE WEST AND
DRIER AIR PUSHES IN FROM THE WEST. ZONAL FLOW FOR MONDAY WILL LEAD
TO PRIMARILY DRY CONDITIONS. THE EXCEPTION WILL BE THE FAR NORTH
WHERE ENOUGH MOISTURE WILL LINGER TO AT LEAST GENERATE
OROGRAPHICALLY-DRIVEN CONVECTION. THE NEXT PIECE OF ENERGY WILL DIG
SOUTHEAST ALONG THE FRONT SIDE OF AN EASTERN PACIFIC RIDGE MONDAY.
THIS WILL REINFORCE THE TROUGH FOR TUESDAY AND BRING ANOTHER SHOT OF
COOLER AIR AND INCREASE PRECIP CHANCES ACROSS THE WEST.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT NE ACROSS
WYOMING OVERNIGHT...INTO EASTERN MONTANA TUESDAY MORNING.  A LINE OF
WEAKENING SHOWERS AND ISOLATED THUNDERSTORMS MOVING INTO FAR WEST
WYOMING AT 06Z WILL RESULT IN HIGHER MTN OBSCURATIONS AND RAIN
SHOWERS MOVING INTO VCNTY KJAC-KAFO THROUGH AROUND 09Z.  OTHERWISE
SCATTERED SHOWERS WITH CIGS MAINLY FL100-130 AND OCCASIONAL MTN
OBSCURATIONS WILL CONTINUE MAINLY VCNTY AND NORTH OF A
KJAC-KWRL-KBYG LINE THROUGH 12Z...MOSTLY LIFTING INTO CENTRAL AND
EASTERN MONTANA AFTER 12Z.

AN UPPER TROUGH OVER THE NW U.S. WILL EJECT THE NEXT DISTURBANCE
ACROSS IDAHO ON WEDNESDAY AFTERNOON AND ACROSS NORTHERN WYOMING
WEDNESDAY NIGHT.  EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO
SPREAD INTO WESTERN WYOMING THROUGH THE AFTERNOON WITH THE BETTER
COVERAGE VCNTY AND NORTH OF A KJAC-KDUB LINE.  THIS ACTIVITY WILL
SPREAD INTO NORTH CENTRAL WYOMING THROUGH THE LATE AFTERNOON AND
EVENING.  SHOWER AND THUNDERSTORM ACTIVITY WILL BE MUCH MORE
ISOLATED ACROSS CENTRAL WYOMING WED AFTN/EVE...VCNTY KLND-KRIW-KCPR.



&&

.FIRE WEATHER...

HEIGHTS AND TEMPERATURES ARE SHOWING A LOWERING AND COOLING TREND
OVER THE NEXT WEEK. ANOTHER SURGE OF MONSOONAL MOISTURE WILL ARRIVE
TODAY AND WILL BRING SHOWERS AND WET THUNDERSTORMS THROUGH AT LEAST
THURSDAY. THERE COULD BE A COLD FRONT ARRIVING THIS WEEKEND THAT
WILL DROP TEMPERATURES FURTHER...TO WELL BELOW NORMAL FOR THIS TIME
OF YEAR...ALONG WITH BRING ANOTHER DOSE OF WETTING RAINS TO THE
REGION. RELATIVE HUMIDITY WILL REMAIN ON THE HIGH SIDE AND THERE ARE
NO WIDESPREAD HIGH WIND EVENTS ON THE HORIZON EITHER.

FORECAST CONFIDENCE IS PRETTY LOW ONCE WE GET INTO NEXT WEEK. THERE ARE
SOME INDICATIONS THAT THERE COULD BE ANOTHER RIDGE BUILDING IN WHILE
OTHER MODELS ARE POINTING TO AN EXACTLY OPPOSITE SOLUTION. THAT
SAID...WHILE THERE COULD BE SOME IGNITIONS WITH THE LIGHTNING OVER
THE NEXT SEVERAL DAYS...THERE WILL BE PLENTY OF RAIN TO ACCOMPANY
THE STORMS...ESPECIALLY ONCE WE GET PAST THIS AFTERNOON WITH MORE
MUD SLIDES...FLASH FLOODING...AND DIFFICULT TRAVEL ALONG ANY BACK
COUNTRY OR UNPAVED ROADS.

&&

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

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN










000
FXUS65 KRIW 200547
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1147 PM MDT TUE AUG 19 2014


.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 221 PM MDT)

TONIGHT WE WILL TRANSITION TO MORE OF A WIDESPREAD SHOWER/ISOLATED
THUNDERSTORM WITH HEAVY RAIN SCENARIO AS THE RICH MOISTURE IS
STIRRED UP BY SOME PVA AND DECENT QG FORCING THROUGH ABOUT 06Z.
THERE WILL BE SOME FLASH FLOOD POTENTIAL...ESPECIALLY EARLY WITH
HEAVIER STORMS AND OVR HIGHER TERRAIN OVERNIGHT WHERE TERRAIN FORCED
RAINFALL WITH CONVECTIVE ELEMENTS COINCIDE...ESPECIALLY ON S TO SW
FACING SLOPES OVERNIGHT AND THRU WED MORNING. LIKED THE OVERNIGHT
SHIFT THINKING WITH AVOIDING A FLASH FLOOD WATCH...SINCE THIS EVENT
WILL BE PARTIALLY CONVECTIVE...THEN STRATIFORM LATER
TONIGHT...CHOOSING TO WAIT AND SEE HOW ALL THIS EVOLVES.
HOWEVER...LATER DURING THIS FCST PERIOD...A FFW MAY BE NECESSARY
ACROSS SOME OF THE WRN MOUNTAIN ZONES AS THE GROUND SATURATES AND
PRECIPITATION KEEPS FALLING THROUGH AT LEAST THURSDAY.

WEDNESDAY AND THURSDAY...ABUNDANT MOISTURE REMAINS IN THE REGION BUT
THE UPPER LEVEL FORCING LEAVES FOR WEDNESDAY...EXPECT MORE OF AN
AIRMASS/DIURNAL THUNDERSTORM SETUP. THERE HAVE BEEN SOME MODEL
UNCERTAINTIES AS TO WHAT WILL ARRIVE ON THURSDAY...BUT THERE MAY BE
SOME MORE BROAD LIFT ARRIVING WITH ANOTHER SHORT WAVE QUICKLY
FOLLOWED BY A LONG WAVE TROUGH ACROSS THE GREAT BASIN TAKING ON A
NEGATIVE TILT AND MOVING OUR DIRECTION...IF THIS SHOULD HAPPEN THEN
SOME MORE ORGANIZED THUNDERSTORM ACTIVITY COULD VISIT THE FORECAST
AREA BUT HAVE KEPT A HEALTHY DOSE OF UNCERTAINTY IN THE GRIDS AT
THIS TIME. IN ANY EVENT...IT IS LIKELY THAT MUCH OF THE FORECAST
AREA WILL CONTINUE TO SEE BOUTS OF HEAVY RAIN THROUGH THURSDAY AND
PERHAPS EVEN FRIDAY...ESPECIALLY ACROSS THE WESTERN
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY

MEDIUM-RANGE MODEL SOLUTIONS ARE IN FAIR AGREEMENT TODAY. BROAD
TROUGH ACROSS THE NORTHWEST U.S. TO BEGIN THE FORECAST PERIOD WITH
HIGH PRESSURE OVER THE SOUTHERN U.S. HELPING TO SLOW THE EASTWARD
PROGRESSION OF THE TROUGH. MODELS HAVE SLOWED SOME FROM MONDAY RUNS
REGARDING THE UPCOMING WEEKEND WEATHER SYSTEM. OVERALL...COOLER
PATTERN TO BE IN PLACE ACROSS THE ROCKIES THROUGH THE PERIOD.

LONG WAVE TROUGH WILL BE POSITIONED OVER THE INTERMOUNTAIN WEST AND
PACIFIC NORTHWEST TO BEGIN THE PERIOD. WEAK SHORTWAVE ENERGY IS
LIKELY TO BE EJECTED EASTWARD ACROSS WYOMING FRIDAY NIGHT AND FAVOR
PRECIPITATION IN THE NORTHWEST AND NORTHERN MOUNTAINS. HAVE NUDGED
PRECIP CHANCES UPWARD IN THESE TWO LOCATIONS. THIS SCENARIO IS
LIKELY TO PLAY OUT THROUGH SATURDAY AS THE TROUGH NEARS WYOMING AND
SOUTHWEST FLOW ALOFT REMAINS OVER THE FORECAST AREA. SOME ADDITIONAL
SUB-TROPICAL MOISTURE WILL BE DRAWN NORTH INTO WYOMING SATURDAY
AFTERNOON AND EVENING. HAVE INCREASED PRECIP CHANCES EAST OF THE
DIVIDE TO ACCOUNT FOR THIS. IF MODELS CONTINUE TO COME MORE IN-LINE
IT IS LIKELY THAT PRECIP CHANCES WOULD NEED TO BE BUMPED UP AND
EXPANDED WEST SATURDAY AFTERNOON AND EVENING. MID-LEVEL CIRCULATION
WILL MOVE ALONG OUR NORTHERN BORDER SATURDAY NIGHT KEEPING SHOWERS
GOING ALL NIGHT ACROSS THE NORTH. THIS CIRCULATION WILL SWING TO OUR
EAST BY MIDDAY SUNDAY SUBSEQUENTLY DRAWING COOLER AIR SOUTH ACROSS
WYOMING IN CYCLONIC FLOW. FAVORABLE WEST-NORTHWEST FLOW SHOULD KEEP
THE BIGHORNS AND PORTIONS OF THE NORTHWEST MOUNTAINS WET SUNDAY
AFTERNOON/NIGHT. ELSEWHERE...THE SOUTHWEST LOOKS TO BE THE DRIEST
AREA SUNDAY AND SUNDAY NIGHT AS THE UPPER FLOW BACKS TO THE WEST AND
DRIER AIR PUSHES IN FROM THE WEST. ZONAL FLOW FOR MONDAY WILL LEAD
TO PRIMARILY DRY CONDITIONS. THE EXCEPTION WILL BE THE FAR NORTH
WHERE ENOUGH MOISTURE WILL LINGER TO AT LEAST GENERATE
OROGRAPHICALLY-DRIVEN CONVECTION. THE NEXT PIECE OF ENERGY WILL DIG
SOUTHEAST ALONG THE FRONT SIDE OF AN EASTERN PACIFIC RIDGE MONDAY.
THIS WILL REINFORCE THE TROUGH FOR TUESDAY AND BRING ANOTHER SHOT OF
COOLER AIR AND INCREASE PRECIP CHANCES ACROSS THE WEST.

&&

.AVIATION.../06Z ISSUANCE/

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL CONTINUE TO DRIFT NE ACROSS
WYOMING OVERNIGHT...INTO EASTERN MONTANA TUESDAY MORNING.  A LINE OF
WEAKENING SHOWERS AND ISOLATED THUNDERSTORMS MOVING INTO FAR WEST
WYOMING AT 06Z WILL RESULT IN HIGHER MTN OBSCURATIONS AND RAIN
SHOWERS MOVING INTO VCNTY KJAC-KAFO THROUGH AROUND 09Z.  OTHERWISE
SCATTERED SHOWERS WITH CIGS MAINLY FL100-130 AND OCCASIONAL MTN
OBSCURATIONS WILL CONTINUE MAINLY VCNTY AND NORTH OF A
KJAC-KWRL-KBYG LINE THROUGH 12Z...MOSTLY LIFTING INTO CENTRAL AND
EASTERN MONTANA AFTER 12Z.

AN UPPER TROUGH OVER THE NW U.S. WILL EJECT THE NEXT DISTURBANCE
ACROSS IDAHO ON WEDNESDAY AFTERNOON AND ACROSS NORTHERN WYOMING
WEDNESDAY NIGHT.  EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO
SPREAD INTO WESTERN WYOMING THROUGH THE AFTERNOON WITH THE BETTER
COVERAGE VCNTY AND NORTH OF A KJAC-KDUB LINE.  THIS ACTIVITY WILL
SPREAD INTO NORTH CENTRAL WYOMING THROUGH THE LATE AFTERNOON AND
EVENING.  SHOWER AND THUNDERSTORM ACTIVITY WILL BE MUCH MORE
ISOLATED ACROSS CENTRAL WYOMING WED AFTN/EVE...VCNTY KLND-KRIW-KCPR.



&&

.FIRE WEATHER...

HEIGHTS AND TEMPERATURES ARE SHOWING A LOWERING AND COOLING TREND
OVER THE NEXT WEEK. ANOTHER SURGE OF MONSOONAL MOISTURE WILL ARRIVE
TODAY AND WILL BRING SHOWERS AND WET THUNDERSTORMS THROUGH AT LEAST
THURSDAY. THERE COULD BE A COLD FRONT ARRIVING THIS WEEKEND THAT
WILL DROP TEMPERATURES FURTHER...TO WELL BELOW NORMAL FOR THIS TIME
OF YEAR...ALONG WITH BRING ANOTHER DOSE OF WETTING RAINS TO THE
REGION. RELATIVE HUMIDITY WILL REMAIN ON THE HIGH SIDE AND THERE ARE
NO WIDESPREAD HIGH WIND EVENTS ON THE HORIZON EITHER.

FORECAST CONFIDENCE IS PRETTY LOW ONCE WE GET INTO NEXT WEEK. THERE ARE
SOME INDICATIONS THAT THERE COULD BE ANOTHER RIDGE BUILDING IN WHILE
OTHER MODELS ARE POINTING TO AN EXACTLY OPPOSITE SOLUTION. THAT
SAID...WHILE THERE COULD BE SOME IGNITIONS WITH THE LIGHTNING OVER
THE NEXT SEVERAL DAYS...THERE WILL BE PLENTY OF RAIN TO ACCOMPANY
THE STORMS...ESPECIALLY ONCE WE GET PAST THIS AFTERNOON WITH MORE
MUD SLIDES...FLASH FLOODING...AND DIFFICULT TRAVEL ALONG ANY BACK
COUNTRY OR UNPAVED ROADS.

&&

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

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...AEM
FIRE WEATHER...ALLEN









000
FXUS65 KRIW 192021
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
221 PM MDT TUE AUG 19 2014

NEAR TERM...A MONSOONAL PUSH WAS BEGINNING TO MOVE INTO SOUTHWESTERN
PORTIONS OF THE FORECAST AREA AS OF 2PM...IT IS EXPECTED TO CONTINUE
ITS TREK NORTH AND EAST OVERSPREADING THE ENTIRE FORECAST AREA
THIS EVENING. DEW POINTS IN THE 50S AND EVEN 60 DEGREES WILL
ACCOMPANY THIS PUSH ALONG WITH PRECIPITABLE WATER VALUES WELL
ABOVE NORMAL...APPROACHING ONE INCH BY THIS EVENING WHICH PUTS US
IN THE 99TH PERCENTILE FOR THIS TIME OF YEAR.

AT THE SAME TIME...A SHORT WAVE THAT MOVED THROUGH UTAH OVERNIGHT
INTO THIS MORNING WILL MAKE ITS WAY INTO THE REGION...SUPPLYING
BROAD SCALE LIFT AND ENCOURAGING WIDESPREAD SHOWERS WITH SOME
EMBEDDED THUNDERSTORMS. WE ARE EXPECTING THE BULK OF THIS ENERGY TO
AFFECT THE SOUTHERN COUNTIES EARLY THIS AFTERNOON AND THEN
TRANSITION INTO CENTRAL AND EASTERN WYOMING LATER THIS EVENING. ALSO
AHEAD OF THIS FEATURE...THERE WILL BE SOME AREAS THAT WILL
DESTABILIZE IF SKIES ARE CLEAR ENOUGH...THIS IS PROBABLY WHERE THE
STRONGER STORMS WILL BE EARLY IN THE PERIOD. DEW POINTS ARE STILL
LOW ENOUGH TO ENCOURAGE SOME WIND GUSTS IN EXCESS OF 45 MPH AND
UPDRAFTS COULD BE STRONG ENOUGH TO SUPPORT SOME PENNY SIZED HAIL.
VILS WOULD HAVE TO EXCEED 65 IN ORDER TO GET LARGER HAIL...WHILE
THAT IS POSSIBLE IT IS DOUBTFUL THAT WE WILL BE ABLE TO MUSTER
ENOUGH CAPE...ESPECIALLY SINCE SHEAR WILL NOT BE STRONG ENOUGH TO
MAINTAIN MUCH OF AN UPDRAFT WITH ANY OF THESE STORMS.

.SHORT TERM...TONIGHT THROUGH FRIDAY

TONIGHT WE WILL TRANSITION TO MORE OF A WIDESPREAD SHOWER/ISOLATED
THUNDERSTORM WITH HEAVY RAIN SCENARIO AS THE RICH MOISTURE IS
STIRRED UP BY SOME PVA AND DECENT QG FORCING THROUGH ABOUT 06Z.
THERE WILL BE SOME FLASH FLOOD POTENTIAL...ESPECIALLY EARLY WITH
HEAVIER STORMS AND OVR HIGHER TERRAIN OVERNIGHT WHERE TERRAIN FORCED
RAINFALL WITH CONVECTIVE ELEMENTS COINCIDE...ESPECIALLY ON S TO SW
FACING SLOPES OVERNIGHT AND THRU WED MORNING. LIKED THE OVERNIGHT
SHIFT THINKING WITH AVOIDING A FLASH FLOOD WATCH...SINCE THIS EVENT
WILL BE PARTIALLY CONVECTIVE...THEN STRATIFORM LATER
TONIGHT...CHOOSING TO WAIT AND SEE HOW ALL THIS EVOLVES.
HOWEVER...LATER DURING THIS FCST PERIOD...A FFW MAY BE NECESSARY
ACROSS SOME OF THE WRN MOUNTAIN ZONES AS THE GROUND SATURATES AND
PRECIPITATION KEEPS FALLING THROUGH AT LEAST THURSDAY.

WEDNESDAY AND THURSDAY...ABUNDANT MOISTURE REMAINS IN THE REGION BUT
THE UPPER LEVEL FORCING LEAVES FOR WEDNESDAY...EXPECT MORE OF AN
AIRMASS/DIURNAL THUNDERSTORM SETUP. THERE HAVE BEEN SOME MODEL
UNCERTAINTIES AS TO WHAT WILL ARRIVE ON THURSDAY...BUT THERE MAY BE
SOME MORE BROAD LIFT ARRIVING WITH ANOTHER SHORT WAVE QUICKLY
FOLLOWED BY A LONG WAVE TROUGH ACROSS THE GREAT BASIN TAKING ON A
NEGATIVE TILT AND MOVING OUR DIRECTION...IF THIS SHOULD HAPPEN THEN
SOME MORE ORGANIZED THUNDERSTORM ACTIVITY COULD VISIT THE FORECAST
AREA BUT HAVE KEPT A HEALTHY DOSE OF UNCERTAINTY IN THE GRIDS AT
THIS TIME. IN ANY EVENT...IT IS LIKELY THAT MUCH OF THE FORECAST
AREA WILL CONTINUE TO SEE BOUTS OF HEAVY RAIN THROUGH THURSDAY AND
PERHAPS EVEN FRIDAY...ESPECIALLY ACROSS THE WESTERN
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY

MEDIUM-RANGE MODEL SOLUTIONS ARE IN FAIR AGREEMENT TODAY. BROAD
TROUGH ACROSS THE NORTHWEST U.S. TO BEGIN THE FORECAST PERIOD WITH
HIGH PRESSURE OVER THE SOUTHERN U.S. HELPING TO SLOW THE EASTWARD
PROGRESSION OF THE TROUGH. MODELS HAVE SLOWED SOME FROM MONDAY RUNS
REGARDING THE UPCOMING WEEKEND WEATHER SYSTEM. OVERALL...COOLER
PATTERN TO BE IN PLACE ACROSS THE ROCKIES THROUGH THE PERIOD.

LONG WAVE TROUGH WILL BE POSITIONED OVER THE INTERMOUNTAIN WEST AND
PACIFIC NORTHWEST TO BEGIN THE PERIOD. WEAK SHORTWAVE ENERGY IS
LIKELY TO BE EJECTED EASTWARD ACROSS WYOMING FRIDAY NIGHT AND FAVOR
PRECIPITATION IN THE NORTHWEST AND NORTHERN MOUNTAINS. HAVE NUDGED
PRECIP CHANCES UPWARD IN THESE TWO LOCATIONS. THIS SCENARIO IS
LIKELY TO PLAY OUT THROUGH SATURDAY AS THE TROUGH NEARS WYOMING AND
SOUTHWEST FLOW ALOFT REMAINS OVER THE FORECAST AREA. SOME ADDITIONAL
SUB-TROPICAL MOISTURE WILL BE DRAWN NORTH INTO WYOMING SATURDAY
AFTERNOON AND EVENING. HAVE INCREASED PRECIP CHANCES EAST OF THE
DIVIDE TO ACCOUNT FOR THIS. IF MODELS CONTINUE TO COME MORE IN-LINE
IT IS LIKELY THAT PRECIP CHANCES WOULD NEED TO BE BUMPED UP AND
EXPANDED WEST SATURDAY AFTERNOON AND EVENING. MID-LEVEL CIRCULATION
WILL MOVE ALONG OUR NORTHERN BORDER SATURDAY NIGHT KEEPING SHOWERS
GOING ALL NIGHT ACROSS THE NORTH. THIS CIRCULATION WILL SWING TO OUR
EAST BY MIDDAY SUNDAY SUBSEQUENTLY DRAWING COOLER AIR SOUTH ACROSS
WYOMING IN CYCLONIC FLOW. FAVORABLE WEST-NORTHWEST FLOW SHOULD KEEP
THE BIGHORNS AND PORTIONS OF THE NORTHWEST MOUNTAINS WET SUNDAY
AFTERNOON/NIGHT. ELSEWHERE...THE SOUTHWEST LOOKS TO BE THE DRIEST
AREA SUNDAY AND SUNDAY NIGHT AS THE UPPER FLOW BACKS TO THE WEST AND
DRIER AIR PUSHES IN FROM THE WEST. ZONAL FLOW FOR MONDAY WILL LEAD
TO PRIMARILY DRY CONDITIONS. THE EXCEPTION WILL BE THE FAR NORTH
WHERE ENOUGH MOISTURE WILL LINGER TO AT LEAST GENERATE
OROGRAPHICALLY-DRIVEN CONVECTION. THE NEXT PIECE OF ENERGY WILL DIG
SOUTHEAST ALONG THE FRONT SIDE OF AN EASTERN PACIFIC RIDGE MONDAY.
THIS WILL REINFORCE THE TROUGH FOR TUESDAY AND BRING ANOTHER SHOT OF
COOLER AIR AND INCREASE PRECIP CHANCES ACROSS THE WEST.

&&

.AVIATION.../00Z ISSUANCE/

A SURGE OF MOISTURE MOVING INTO SOUTHERN WY ALREADY VCNTY KRKS WILL
CONTINUE TO MOVE NORTH THROUGH 06Z. AHEAD OF THE MAIN PUSH EXPECT
ANY AREAS WITH PARTLY CLOUDY OR CLEAR SKIES TO SEE -SHRA AND -TSRA
TO DEVELOP 18-21Z OVER THE MOUNTAINS FIRST AND SPREAD INTO THE
FOOTHILLS SHORTLY THEREAFTER...MAINLY FROM A KEVW TO VCNTY KAFO IN
THE EARLY AFTERNOON PUSHING INTO NW WYOMING VCNTY AND NORTH OF KJAC
IN THE LATE AFTERNOON AND EVENING. THUNDERSTORM COVERAGE WILL BE
MORE ISOLATED FURTHER EAST. EXPECT OCCNL MVFR CONDITIONS...MOUNTAIN
OBSCURATIONS AND TURBULENCE VCNTY TSRA.

THE SYSTEM WILL SPREAD SCT-NMRS SHRA S-N ACROSS WEST AND CENTRAL
WYOMING AFTER 00Z WITH A FEW EMBEDDED THUNDERSTORMS LINGERING. CIGS
WILL LOWER MAINLY INTO THE FL050-100 RANGE WITH ALONG WITH HIGHER
MTN OBSCURATIONS AND POSSIBLY LCL MVFR CONDITIONS IN RA AND BR.
GRADUAL IMPROVEMENT IS EXPECTED FROM SW-NE AFTER 10Z AS THE SYSTEM
LIFTS INTO NE WYOMING.

&&

.FIRE WEATHER...

HEIGHTS AND TEMPERATURES ARE SHOWING A LOWERING AND COOLING TREND
OVER THE NEXT WEEK. ANOTHER SURGE OF MONSOONAL MOISTURE WILL ARRIVE
TODAY AND WILL BRING SHOWERS AND WET THUNDERSTORMS THROUGH AT LEAST
THURSDAY. THERE COULD BE A COLD FRONT ARRIVING THIS WEEKEND THAT
WILL DROP TEMPERATURES FURTHER...TO WELL BELOW NORMAL FOR THIS TIME
OF YEAR...ALONG WITH BRING ANOTHER DOSE OF WETTING RAINS TO THE
REGION. RELATIVE HUMIDITY WILL REMAIN ON THE HIGH SIDE AND THERE ARE
NO WIDESPREAD HIGH WIND EVENTS ON THE HORIZON EITHER.

FORECAST CONFIDENCE IS PRETTY LOW ONCE WE GET INTO NEXT WEEK. THERE ARE
SOME INDICATIONS THAT THERE COULD BE ANOTHER RIDGE BUILDING IN WHILE
OTHER MODELS ARE POINTING TO AN EXACTLY OPPOSITE SOLUTION. THAT
SAID...WHILE THERE COULD BE SOME IGNITIONS WITH THE LIGHTNING OVER
THE NEXT SEVERAL DAYS...THERE WILL BE PLENTY OF RAIN TO ACCOMPANY
THE STORMS...ESPECIALLY ONCE WE GET PAST THIS AFTERNOON WITH MORE
MUD SLIDES...FLASH FLOODING...AND DIFFICULT TRAVEL ALONG ANY BACK
COUNTRY OR UNPAVED ROADS.

&&

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

$$

SHORT TERM...ALLEN
LONG TERM...CNJ
AVIATION...ALLEN
FIRE WEATHER...ALLEN






000
FXUS65 KRIW 191729 AAA
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1129 AM MDT TUE AUG 19 2014

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT

WV IMAGERY SHOWING WEAK/FLAT RIDGING WITH A SLIGHT TILT TOWARD NW
FLOW. UPSTREAM...A SMALL BUT VIGOROUS SW IS BEING KICKED OUT AHEAD
OF THE MAIN CLOSED TROF OVR THE W COAST...IS NOW LOCATED FROM ERN NV
THRU CNTRL UT AND WILL IMPACT THE FA THRU THE DAY TODAY. FURTHER
UPSTREAM AND NW OF THE W COAST TROF...SW TROF JUST NOW MOVING INTO W
COAST OF BC WILL EFFECT THE REGION THRU THE MID/END OF WEEK PERIOD.
AT THE SFC...GENERAL LOW P ACROSS THE GREAT BASIN WITH SLIGHTLY
HIGHER P OVR WY. WEAK SFC BOUNDARY STRETCHING ACROSS THE SRN PORTION
OF WY FROM W TO E.

TODAY...FLAT UPR RIDGING TO SLIGHT NW FLOW OVR THE FA WILL BREAK
DOWN THRU THE DAY WITH THE ARRIVAL OF A RELATIVELY STRONG UPR WAVE
SHOOTING OUT AHEAD OF OUT THE WRN CONUS LOW P TROF. THE SFC WILL
RESPOND BY DEVELOPING/EVOLVING SFC LOW ENTERING THE STATE FROM THE S
WITH SFC BOUNDARY/TROF EXTENDING FROM S CNTRL TO NERN WY.
ADDITIONALLY...MONSOONAL MOISTURE IS HEADED BACK INTO THE STATE AND
WILL COMBINE WITH MOISTURE ASSOCIATED WITH THE SHORTWAVE COMING FROM
THE EPAC...GIVING A DEEP TROPICAL MOISTURE PROFILE TO MUCH OF REGION
THRU TONIGHT. PWS IN THE DESERT CONUS SW ARE INCREASING AND RANGING
FROM 1 TO 2 INCHES. INCREASING CHANCES FOR SCATTERED TO NUMEROUS
+SHRA/+TSRA WITH GUSTY WINDS...SMALL HAIL AND PERIODS OF VERY HEAVY
RAIN BY MID TO LATE AFTERNOON ACROSS THE SW/WRN ZONES...ISOLATED
EVERYWHERE ELSE. THRU THE EVENING...TRANSITIONING TO MORE OF A
STRATIFORM RAIN W/ ISOLATED EMBEDDED SHRA/TSRA REGIME. THERE WILL BE
SOME FLASH FLOOD POTENTIAL...ESPECIALLY EARLY WITH HEAVIER STORMS
AND OVR HIGHER TERRAIN OVERNIGHT WHERE TERRAIN FORCED RAINFALL WITH
CONVECTIVE ELEMENTS COINCIDE...ESPECIALLY ON S TO SW FACING SLOPES
OVERNIGHT AND THRU WED MORNING. AN SPS WILL BE SENT WITH THIS
ISSUANCE EXPLAINING THE SITUATION. SINCE THIS EVENT WILL BE
PARTIALLY CONVECTIVE...THEN STRATIFORM LATER TONIGHT...HESITATE IN
ISSUING FFW FOR ALL OF THE WRN MOUNTAINS AT THIS TIME AND ARE
CHOOSING TO WAIT AND SEE HOW ALL THIS EVOLVES. HOWEVER...LATER
DURING THIS FCST PERIOD...A FFW MAY BE NECESSARY ACROSS SOME OF THE
WRN MOUNTAIN ZONES AS THE GROUND SATURATES AND PRECIPITATION KEEPS
FALLING THROUGH AT LEAST THURSDAY.

WEDNESDAY AND THURSDAY...MOISTURE ENTRAINMENT FROM THE EPAC WILL
CONTINUE INTO THE WRN FA ALONG AND AHEAD OF MOBILE NRN BRANCH OF THE
W COAST TROF. MORE MODEST MONSOONAL MOISTURE WILL CONTINUE TO RETURN
INTO THE SRN/SERN ZONES. REGARDLESS OF MOISTURE SOURCE...PERIODS OF
RAINFALL...STRATIFORM AND EMBEDDED CONVECTIVE DURING THE DAYTIME
HRS...WILL CONTINUE THRU THURSDAY BEFORE FINALLY BEGINNING TO WANE
OVERNIGHT THURSDAY. DAYTIME NEARLY MOIST ADIABATIC LAPSE RATES WILL
RANGE FROM 7.5 TO 8.5 C/KM WITH CAPE PEAKING FROM 600 TO 1000 J/KG
DEPENDING ON WARMING WITH LITTLE INHIBITION. PERIODS OF HEAVY
RAINFALL AND SMALL HAIL CAN BE EXPECTED WITH ANY OF THIS EMBEDDED
ACTIVITY. E OF THE DIVIDE...CONVECTION WILL BE SOMEWHAT MORE
ISOLATED IN NATURE WITH LESS MOISTURE TO WORK WITH AND GUSTY WINDS
STILL A POSSIBILITY.

.LONG TERM...FRIDAY THROUGH TUESDAY
MEDIUM RANGE PERIOD LOOKS TO STILL BE DOMINATED BY A RIDGE ALONG
AND JUST OFF THE PACNW COAST NWD TO JUST OFFSHORE THE B.C. COAST
AND A RELOADING TROUGH OVER THE NRN ROCKIES/INTERMOUNTAIN WEST.
FORECAST LEANING MORE ON THE MORE CONSISTENT GFS. THE ECMWF HAS
HAD SOME WILD SWINGS SINCE LAST NIGHT RANGING FROM A TROUGH EARLY
NEXT WEEK JUST TO OUR WEST...THEN A BIG RIDGE AND NOW ANOTHER COLD
TROUGH SWINGING THROUGH AT THE END OF THE MEDIUM RANGE PERIOD. THE
GFS IS CHANGING WITH EACH RUN TOO BUT NOT WITH AS WILD OF SWINGS.
CONFIDENCE STILL LOW ON TIMING AND DETAILS FOR EARLY NEXT WEEK.
TROUGH HANGS JUST TO THE WEST FRIDAY AND THEN STARTS TO SWING EWD
ON SATURDAY. THE GFS KEEPS A FRONTAL BOUNDARY DRAPED ACROSS THE NE
HALF OF THE AREA WITH NE UPSLOPE AND HIGHER DEW POINTS AND THUS
HIGHER CAPES. KEEPING THE HIGHER CHANCE POPS BEHIND THE EXPECTED
FRONT IN THIS AREA ALONG WITH COOLER TEMPERATURES. MILDER WITH
LOWER TO NIL POPS FURTHER SW. BRIEF SHORTWAVE RIDGING POSSIBLE
SUNDAY BEFORE THE NEXT SHORTWAVE RELOADS/REDEVELOPS THE MEAN TROUGH
OVER THE INTERMOUNTAIN WEST. MAINLY ISOLD POPS IN THE NORTH AND
WEST. NEXT TROUGH EARLY NEXT WEEK COULD BE QUITE COOL WITH A GOOD
CHANCE OF SHOWERS AND SOME THUNDERSTORMS ACROSS AT LEAST THE NORTH
HALF. THE GFS IS NOT AS FAR SOUTH WITH THIS SYSTEM AS THE ECMWF
BUT BOTH WOULD INDICATE A GOOD CHANCE OF PCPN FOR AT LEAST THE
NORTH AND EVEN FURTHER SOUTH IF THE EURO IS RIGHT. FOR NOW GOING
WITH CHANCE MTN POPS AND ISOLD ELSEWHERE. ENOUGH COOL AIR WITH THE
FRIDAY/SATURDAY SYSTEM TO PRODUCE SOME HIGHER MOUNTAIN SNOW BUT
MAINLY ABOVE 10-11K. SYSTEM EARLY NEXT WEEK HAS THE POTENTIAL TO
BE COLDER YET WITH SNOW LEVEL DOWN TO 9K OR SO BY TUESDAY/TUESDAY
NIGHT BUT CONFIDENCE STILL LOW ON THE DETAILS THIS FAR OUT.

.AVIATION.../18Z ISSUANCE/

A SURGE OF MOISTURE MOVING INTO SOUTHERN WY ALREADY VCNTY KRKS
WILL CONTINUE TO MOVE NORTH THROUGH 06Z. AHEAD OF THE MAIN PUSH
EXPECT ANY AREAS WITH PARTLY CLOUDY OR CLEAR SKIES TO SEE
-SHRA AND -TSRA TO DEVELOP 18-21Z OVER THE MOUNTAINS FIRST AND
SPREAD INTO THE FOOTHILLS SHORTLY THEREAFTER...MAINLY FROM A KEVW
TO VCNTY KAFO IN THE EARLY AFTERNOON PUSHING INTO NW WYOMING VCNTY
AND NORTH OF KJAC IN THE LATE AFTERNOON AND EVENING. THUNDERSTORM
COVERAGE WILL BE MORE ISOLATED FURTHER EAST. EXPECT OCCNL MVFR
CONDITIONS...MOUNTAIN OBSCURATIONS AND TURBULENCE VCNTY TSRA.

THE SYSTEM WILL SPREAD SCT-NMRS SHRA S-N ACROSS WEST AND CENTRAL
WYOMING AFTER 00Z WITH A FEW EMBEDDED THUNDERSTORMS LINGERING. CIGS
WILL LOWER MAINLY INTO THE FL050-100 RANGE WITH ALONG WITH HIGHER
MTN OBSCURATIONS AND POSSIBLY LCL MVFR CONDITIONS IN RA AND BR.
GRADUAL IMPROVEMENT IS EXPECTED FROM SW-NE AFTER 10Z AS THE SYSTEM
LIFTS INTO NE WYOMING.

.FIRE WEATHER...

FIRE WEATHER CONCERNS WILL CONTINUE TO FALL TODAY...REMAINING LOW
ACROSS MOST OF THE FORECAST AREA THROUGH AT LEAST THURSDAY. THE
BIG HORN BASIN HOWEVER WILL REMAIN RELATIVELY DRY FOR MOST OF THE
DAY...BUT WINDS WILL REMAIN WELL UNDER 15 MPH FOR TH MOST PART.
THE REASON FOR THE LOW CONCERN IS THAT BOTH MONSOONAL AND PACIFIC
MOISTURE WILL INFILTRATE THE STATE WITH INCREASING RAINFALL
CHANCES STATEWIDE BY EVENING AS A VIGOROUS UPPER LEVEL DISTURBANCE
HELPS IN DEVELOPING SHOWERS AND THUNDERSTORMS FROM THIS MOISTURE.
THE OVERNIGHT PERIODS WILL GENERALLY SEE MORE STRATIFORM AND
LIGHTER RAINFALL WHILE DAYTIME PERIODS WILL BE CHARACTERIZED BY
BOTH STRATIFORM RAIN WITH EMBEDDED ISOLATED THUNDER. HEAVY RAIN
WILL BE POSSIBLE AT TIMES...ESPECIALLY DURING THE DAYS.

&&

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

$$

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






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