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000
FXUS65 KRIW 200531
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1131 PM MDT SAT APR 19 2014

.SHORT TERM...TONIGHT THROUGH TUESDAY (ISSUED AT 156 PM MDT)

WEAK SHORTWAVE MOVED INTO THE SW THIS MORNING WITH ACCAS AND
SPRINKLES. THIS AREA HAS NOW TURNED INTO LIGHT SHOWERS AND IS
MERGING WITH OUR MOISTURE...LEFTOVER FRONTAL BOUNDARY AND DAYTIME
HEATING TO PRODUCING SOME BUILDING CUMULUS OVER SWEETWATER COUNTY.
IDEA OF MAINLY ISOLATED SHOWERS AND A COUPLE THUNDERSTORMS IS
LOOKING GOOD WITH A FEW MORE OVER THE MOUNTAINS. COUPLE LIGHTNING
STRIKES JUST SOUTH OF THE BORDER SO FAR. NEXT SYSTEM MOVES EWD
AWAY FROM THE UPPER LOW OFF THE B.C. COAST WHICH PUSHES A COLD
FRONT SE ACROSS THE AREA ON EASTER. THE FRONT MAY INTERACT WITH
THE LEFTOVER MOISTURE FROM TODAY`S SYSTEM OVER OUR FAR SERN ZONES
TO PROVIDE ANOTHER DAY OF MAINLY ISOLATED SHOWERS AND PERHAPS A
THUNDERSTORM OR TWO. INSTABILITY LOOKS VERY LIMITED ON
FORECAST/INTERPOLATED SOUNDINGS. OTHERWISE...ANOTHER MILD DAY
WITH TEMPERATURES GENERALLY 60S EAST OF THE DIVIDE AND 50S TO
LOWER 60S WEST. THE MOUNTAINS WILL BE IN THE 40S AND 50S. RIDGE
AXIS MOVES OVERHEAD ON MONDAY WITH SLIGHTLY WARMER TEMPERATURES
YET. COULD BE A FEW SHOWERS TRYING TO DEVELOP OVER THE FAR WEST BY
MONDAY EVENING AS SOME MOISTURE FROM THE ERN FRINGES OF OUR BIG
MIDWEEK SYSTEM WORKS ON A WARM TEMPERATURES MONDAY.
OTHERWISE...MONDAY LOOKS DRY AND MILD TO WARM. TUESDAY WE STILL
OUR BIG NEGATIVELY TILTED UPPER LOW MOVE INTO THE GREAT BASIN WITH
RAPIDLY FALLING PRESSURES AS A SURFACE LOW FORMS OVER MONTANA.
STRONG SLY FLOW WHICH WILL DEVELOP MONDAY NIGHT WILL CONTINUE TO
STRENGTHEN THROUGH THE DAY TUESDAY LEADING TO A WINDY TO VERY
WINDY DAY FOR MOST EVERYONE. COLD FRONT NEAR THE FAR WEST LATE IN
THE DAY WITH A LINE OF SHOWERS AND THUNDERSTORMS QUITE LIKELY OUT
WEST. A FEW OF THESE COULD BE QUITE STRONG EVEN IF IT`S JUST
SHOWERS AND OR THUNDERSTORMS MOVING NWD AND ADDING TO THE AMBIENT
STRONG SLY FLOW PRODUCING VERY STRONG SLY WINDS. EAST OF THE
DIVIDE...DAYTIME HEATING MAY BE ENOUGH FOR ISOLATED SHOWERS AND
THUNDERSTORMS WITH SOME RETURN FLOW MOISTURE AND HIGHER CAPES
POSSIBLE IN JOHNSON COUNTY. OTHERWISE...WARM AND WINDY WITH PCPN
BECOMING FAIRLY WIDESPREAD OUT WEST. SNOW LEVELS WILL BE ABOVE 10K
FEET DURING THE DAY ADDING TO THE RISK OF SOME MODERATE TO LOCALLY
HEAVY RAIN ON DEEP SNOWPACK.

.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY

A VIGOROUS SHORTWAVE TRACKING NORTHEAST AROUND THE BASE OF THE DEEP
TROUGH THAT WILL BE SITUATED ALONG THE CANADIAN/PACIFIC NORTHWEST
COAST TUE NT WILL PRODUCE NUMEROUS RAIN AND SNOW SHOWERS IN THE FAR
WEST TUESDAY NIGHT WITH 2 TO 3 INCHES OF ACCUMULATING SNOW AFTER
MIDNIGHT IN THE FAR WEST. SOME ISOLATED THUNDER ALSO POSSIBLE.
PRECIPITATION WILL SPILL OVER TO AREAS EAST OF THE DIVIDE LATER
TUESDAY NIGHT AND INTO WEDNESDAY. WEDNESDAY WILL FEATURE PRECIP
MAINLY IN THE FORM OF RAIN EXCEPT MOSTLY SNOW IN THE MOUNTAINS. BY
WEDNESDAY...THE AFOREMENTIONED TROUGH WILL CLOSE INTO AN ALMOST
VERTICALLY STACKED LOW OVER MONTANA AS IT TRACKS EAST. HIGH TEMPS
WED SHOULD RUN ABOUT 10 TO 20 DEGREES COOLER COMPARED TO TUE.THERE
WILL BE MORE PRECIP ACROSS THE NORTH HALF OF THE CWA WEDNESDAY NIGHT
CLOSER TO THE TRACK OF THE LOW. DURING THE COURSE OF THE NIGHT
WEDNESDAY NIGHT...H7 TEMPS WILL DROP TO -10C WEST OF THE DIVIDE AND
-8C EAST SO THAT BY 06Z THU...MOST OF WHAT PRECIP OCCURS WILL BE IN
THE FORM OF SNOWFALL. BY WEDNESDAY NIGHT...WITH ENOUGH COLD AIR
ALOFT DESTABILIZING THE ATMOSPHERE...EXPECT CONVECTIVE SNOW BANDS TO
FORM OFF SOUTH PASS...THE OWL CREEK/BRIDGER MTNS AND THE BIG HORN
MTNS IN THE FAVORABLE NORTHWEST FLOW...WITH THESE SNOW BANDS LIKELY
EXTENDING INTO THE LOWER ELEVATIONS OF EASTERN FREMONT...NATRONA AND
JOHNSON COUNTIES AS WELL AS GREATER CASPER. THE ECMWF IS SLOWER THAN
THE GFS WITH THIS TROUGH SO KEPT THE TIMING OF THE PRECIP THE SAME
WHICH IS A BLEND OF THE SPEED OF THE TWO MODELS. SNOWFALL WILL TAPER
OFF THURSDAY MORNING. EXPECT RATHER BENIGN CONDITIONS THU AFT
THROUGH FRIDAY WITH SLIGHTLY ABOVE NORMAL TEMPS. THEN ON SATURDAY
WILL KEEP THE LOW POPS IN THE FAR WEST WITH THE APPROACH OF THE NEXT
UPSTREAM TROUGH WITH THE EURO AGAIN FASTER THAN THE GFS SO WILL KEEP
THE TIMING OF THE ASCT PRECIP THE SAME WITH THE BLEND OF THE TWO
MODELS. TEMPS WILL WARM SOMEWHAT SATURDAY.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR CONDITIONS WILL OCCUR TODAY AND TONIGHT. ISOLATED SHOWERS ARE
POSSIBLE ACROSS SOUTHERN NATRONA COUNTY FROM 21Z SUNDAY UNTIL 02Z
MONDAY. THE SHOWERS ARE NOT FORECAST TO HIT THE KCPR AIRPORT. A COLD
FRONT WILL PUSH THROUGH NORTHERN WY FROM 15Z TO 19Z AND PUSH SOUTH
INTO CENTRAL WY AROUND 00Z MONDAY. A WIND SHIFT TO THE NORTH WILL
BE THE MAIN IMPACT.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

VFR CONDITIONS WILL OCCUR TODAY AND TONIGHT. ISOLATED SHOWERS WILL
BE POSSIBLE OVER THE NW WY MOUNTAINS UNTIL 18Z. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS SOUTHERN WY FROM 19Z SUNDAY UNTIL
02Z MONDAY. THIS ACTIVITY MAY IMPACT THE KRKS AIRPORT DURING THIS
TIMEFRAME.

&&

.FIRE WEATHER...

IT WILL BE MILD TO WARM AND DRY THE REMAINDER OF THE WEEKEND AND
IN MOST AREAS THROUGH MONDAY. THERE WILL BE BREEZY TO WINDY AREAS
AT TIMES AND A COLD FRONT WILL SHIFT WINDS TO THE NORTH ACROSS THE
NORTH AND EAST PART OF THE DISTRICT ON SUNDAY WHILE WEST TO
NORTHWEST WINDS CONTINUE ELSEWHERE. WINDS WILL STRENGTHEN
CONSIDERABLY MONDAY NIGHT AND TUESDAY AHEAD OF A SIGNIFICANT STORM
SYSTEM THAT WILL MOVE EAST ACROSS THE AREA TUESDAY THROUGH
WEDNESDAY. STRONG TO VERY STRONG SOUTHERLY WINDS ARE EXPECTED ON
TUESDAY WITH SHOWERS AND POSSIBLE THUNDERSTORMS DEVELOPING OUT
WEST AND ISOLATED SHOWERS AND THUNDERSTORMS EAST OF THE DIVIDE.

&&

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

&&

$$

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











000
FXUS65 KRIW 191956
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
156 PM MDT SAT APR 19 2014

.SHORT TERM...TONIGHT THROUGH TUESDAY

WEAK SHORTWAVE MOVED INTO THE SW THIS MORNING WITH ACCAS AND
SPRINKLES. THIS AREA HAS NOW TURNED INTO LIGHT SHOWERS AND IS
MERGING WITH OUR MOISTURE...LEFTOVER FRONTAL BOUNDARY AND DAYTIME
HEATING TO PRODUCING SOME BUILDING CUMULUS OVER SWEETWATER COUNTY.
IDEA OF MAINLY ISOLATED SHOWERS AND A COUPLE THUNDERSTORMS IS
LOOKING GOOD WITH A FEW MORE OVER THE MOUNTAINS. COUPLE LIGHTNING
STRIKES JUST SOUTH OF THE BORDER SO FAR. NEXT SYSTEM MOVES EWD
AWAY FROM THE UPPER LOW OFF THE B.C. COAST WHICH PUSHES A COLD
FRONT SE ACROSS THE AREA ON EASTER. THE FRONT MAY INTERACT WITH
THE LEFTOVER MOISTURE FROM TODAY`S SYSTEM OVER OUR FAR SERN ZONES
TO PROVIDE ANOTHER DAY OF MAINLY ISOLATED SHOWERS AND PERHAPS A
THUNDERSTORM OR TWO. INSTABILITY LOOKS VERY LIMITED ON
FORECAST/INTERPOLATED SOUNDINGS. OTHERWISE...ANOTHER MILD DAY
WITH TEMPERATURES GENERALLY 60S EAST OF THE DIVIDE AND 50S TO
LOWER 60S WEST. THE MOUNTAINS WILL BE IN THE 40S AND 50S. RIDGE
AXIS MOVES OVERHEAD ON MONDAY WITH SLIGHTLY WARMER TEMPERATURES
YET. COULD BE A FEW SHOWERS TRYING TO DEVELOP OVER THE FAR WEST BY
MONDAY EVENING AS SOME MOISTURE FROM THE ERN FRINGES OF OUR BIG
MIDWEEK SYSTEM WORKS ON A WARM TEMPERATURES MONDAY.
OTHERWISE...MONDAY LOOKS DRY AND MILD TO WARM. TUESDAY WE STILL
OUR BIG NEGATIVELY TILTED UPPER LOW MOVE INTO THE GREAT BASIN WITH
RAPIDLY FALLING PRESSURES AS A SURFACE LOW FORMS OVER MONTANA.
STRONG SLY FLOW WHICH WILL DEVELOP MONDAY NIGHT WILL CONTINUE TO
STRENGTHEN THROUGH THE DAY TUESDAY LEADING TO A WINDY TO VERY
WINDY DAY FOR MOST EVERYONE. COLD FRONT NEAR THE FAR WEST LATE IN
THE DAY WITH A LINE OF SHOWERS AND THUNDERSTORMS QUITE LIKELY OUT
WEST. A FEW OF THESE COULD BE QUITE STRONG EVEN IF IT`S JUST
SHOWERS AND OR THUNDERSTORMS MOVING NWD AND ADDING TO THE AMBIENT
STRONG SLY FLOW PRODUCING VERY STRONG SLY WINDS. EAST OF THE
DIVIDE...DAYTIME HEATING MAY BE ENOUGH FOR ISOLATED SHOWERS AND
THUNDERSTORMS WITH SOME RETURN FLOW MOISTURE AND HIGHER CAPES
POSSIBLE IN JOHNSON COUNTY. OTHERWISE...WARM AND WINDY WITH PCPN
BECOMING FAIRLY WIDESPREAD OUT WEST. SNOW LEVELS WILL BE ABOVE 10K
FEET DURING THE DAY ADDING TO THE RISK OF SOME MODERATE TO LOCALLY
HEAVY RAIN ON DEEP SNOWPACK.

.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY

A VIGOROUS SHORTWAVE TRACKING NORTHEAST AROUND THE BASE OF THE DEEP
TROUGH THAT WILL BE SITUATED ALONG THE CANADIAN/PACIFIC NORTHWEST
COAST TUE NT WILL PRODUCE NUMEROUS RAIN AND SNOW SHOWERS IN THE FAR
WEST TUESDAY NIGHT WITH 2 TO 3 INCHES OF ACCUMULATING SNOW AFTER
MIDNIGHT IN THE FAR WEST. SOME ISOLATED THUNDER ALSO POSSIBLE.
PRECIPITATION WILL SPILL OVER TO AREAS EAST OF THE DIVIDE LATER
TUESDAY NIGHT AND INTO WEDNESDAY. WEDNESDAY WILL FEATURE PRECIP
MAINLY IN THE FORM OF RAIN EXCEPT MOSTLY SNOW IN THE MOUNTAINS. BY
WEDNESDAY...THE AFOREMENTIONED TROUGH WILL CLOSE INTO AN ALMOST
VERTICALLY STACKED LOW OVER MONTANA AS IT TRACKS EAST. HIGH TEMPS
WED SHOULD RUN ABOUT 10 TO 20 DEGREES COOLER COMPARED TO TUE.THERE
WILL BE MORE PRECIP ACROSS THE NORTH HALF OF THE CWA WEDNESDAY NIGHT
CLOSER TO THE TRACK OF THE LOW. DURING THE COURSE OF THE NIGHT
WEDNESDAY NIGHT...H7 TEMPS WILL DROP TO -10C WEST OF THE DIVIDE AND
-8C EAST SO THAT BY 06Z THU...MOST OF WHAT PRECIP OCCURS WILL BE IN
THE FORM OF SNOWFALL. BY WEDNESDAY NIGHT...WITH ENOUGH COLD AIR
ALOFT DESTABILIZING THE ATMOSPHERE...EXPECT CONVECTIVE SNOW BANDS TO
FORM OFF SOUTH PASS...THE OWL CREEK/BRIDGER MTNS AND THE BIG HORN
MTNS IN THE FAVORABLE NORTHWEST FLOW...WITH THESE SNOW BANDS LIKELY
EXTENDING INTO THE LOWER ELEVATIONS OF EASTERN FREMONT...NATRONA AND
JOHNSON COUNTIES AS WELL AS GREATER CASPER. THE ECMWF IS SLOWER THAN
THE GFS WITH THIS TROUGH SO KEPT THE TIMING OF THE PRECIP THE SAME
WHICH IS A BLEND OF THE SPEED OF THE TWO MODELS. SNOWFALL WILL TAPER
OFF THURSDAY MORNING. EXPECT RATHER BENIGN CONDITIONS THU AFT
THROUGH FRIDAY WITH SLIGHTLY ABOVE NORMAL TEMPS. THEN ON SATURDAY
WILL KEEP THE LOW POPS IN THE FAR WEST WITH THE APPROACH OF THE NEXT
UPSTREAM TROUGH WITH THE EURO AGAIN FASTER THAN THE GFS SO WILL KEEP
THE TIMING OF THE ASCT PRECIP THE SAME WITH THE BLEND OF THE TWO
MODELS. TEMPS WILL WARM SOMEWHAT SATURDAY.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR CONDITIONS WITH ONLY FEW-SCT HIGH CLOUDS AND MAINLY LIGHT WINDS
ARE EXPECTED THROUGH THE FORECAST PERIOD. HOWEVER...SOME ISOLATED
SHOWERS OR EVEN A THUNDERSTORM COULD FORM IN SOUTHEAST SWEETWATER
COUNTY DURING THE REMAINDER OF THIS AFTERNOON. WINDS WILL VEER TO
THE NORTH DURING THE COURSE OF THE AFTERNOON ON SUNDAY AS A WEAK
FRONTAL BOUNDARY PUSHES SOUTH OVER THE AREA.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

THERE IS THE POSSIBILITY OF ISOLATED CONVECTION SOUTH OF INTERSTATE
80. THIS ACTIVITY SHOULD REMAIN SOUTH OF THE KRKS TERMINAL...BUT THE
TERMINAL COULD SEE SOME OUTFLOW WINDS FROM THE ACTIVITY.
OTHERWISE...VFR CONDITIONS AND LIGHT WINDS ARE EXPECTED.

&&

.FIRE WEATHER...

IT WILL BE MILD TO WARM AND DRY THE REMAINDER OF THE WEEKEND AND
IN MOST AREAS THROUGH MONDAY. THERE WILL BE BREEZY TO WINDY AREAS
AT TIMES AND A COLD FRONT WILL SHIFT WINDS TO THE NORTH ACROSS THE
NORTH AND EAST PART OF THE DISTRICT ON SUNDAY WHILE WEST TO
NORTHWEST WINDS CONTINUE ELSEWHERE. WINDS WILL STRENGTHEN
CONSIDERABLY MONDAY NIGHT AND TUESDAY AHEAD OF A SIGNIFICANT STORM
SYSTEM THAT WILL MOVE EAST ACROSS THE AREA TUESDAY THROUGH
WEDNESDAY. STRONG TO VERY STRONG SOUTHERLY WINDS ARE EXPECTED ON
TUESDAY WITH SHOWERS AND POSSIBLE THUNDERSTORMS DEVELOPING OUT
WEST AND ISOLATED SHOWERS AND THUNDERSTORMS EAST OF THE DIVIDE.

&&

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

&&

$$

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








000
FXUS65 KRIW 191727
AFDRIW

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE RIVERTON WY
1127 AM MDT SAT APR 19 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

WV IMAGERY STILL SHOWS PROGRESSIVE/FAST MOVING NRN BRANCH OF POLAR
FLOW ATOP SOMEWHAT SLOWER SRN BRANCH OF SUB-TROPICAL FLOW STRETCHING
ACROSS THE ENTIRE CONUS. THERE ARE NO LESS THAN 5 ACTIVE UPR LOWS
ENCOMPASSING THE CONUS...WITH EACH TRYING TO STEAL SOME THUNDER FROM
THE OTHER...KEEP ALL IN CHECK FOR THE MOST PART. HERE...UPR TROF
THRU WITH A COUPLE OF MOSTLY DRY FRONTS DRAPED ACROSS THE SRN AND
NRN FA. BENIGN HIGH PRESSURE WITH WEAK GRADIENT SLOWLY INFILTRATING
FROM THE NW...REIGNING IN THE WINDS FOR A WHILE ANYWAY.

GENERALLY...TODAY WILL BE SLIGHTLY COOLER THAN FRIDAY...WITH HIGH
TEMPS STILL REACHING INTO THE MIDDLE AND UPPER 60S FOR MOST OF THE
LOWER ELEVATIONS. OTHERWISE...NEARLY STATIONARY FRONT SET UP NEAR/
NORTH OF THE WY/CO BORDER IN OUR SRN MOST ZONES WILL AID IN RENEWED
CONVECTIVE DEVELOPMENT BY MID DAY IN A LARGELY DRY ADIABATIC
ATMOSPHERE. THIS AREA MAY LIFT FAR ENOUGH NORTH THAT SOME ACTIVITY
MAY PRESENT ITSELF OVR SRN NATRONA COUNTY TOO. WON`T HELP MUCH
HOWEVER AS CONVECTIVE MODE WILL HAVE LITTLE MOISTURE TO WORK
WITH...YIELDING MOSTLY DRY SHOWERS/STORMS WITH GUSTY WINDS.

SUNDAY WILL BE NICE OVERALL. THE AFTERNOON WILL OFFER LOW END
CHANCES FOR ISOLATED TO WIDELY SCATTERED SHOWERS WITH SOME THUNDER
AS A WEAK UPR LVL DISTURBANCE AND SFC FRONT RACE THROUGH THE FA.
TIMING AND MARGINALLY AVAILABLE MOISTURE WILL LIMIT THE CONVECTIVE
AREA TO OUR SRN AND SERN ZONES. HOWEVER...THIS WILL BE ANOTHER CASE
OF HIGH BASED SHOWERS/FEW STORMS WITH LITTLE RAIN...AND MORE GUSTY
WINDS. MONDAY THRU MOST OF THE DAY...UPR RIDGE AND STABLE ATMOSPHERE
IN PLACE. BY EVENING HOWEVER...RIDGE AXIS STARTS TO HEAD OUT WHILE
TROF FROM THE WEST BEGINS TO MOVE IN WITH PVA STARTING AS PART OF
POLAR JET...CURRENTLY HOVERING OVR THE EPAC REGION W OF
WA/OR...WORKS ITS WAY INTO THE WRN MOUNTAINS WITH A LITTLE MOISTURE.
THIS WILL HERALD THE BEGINNING OF NEW CYCLOGENESIS IN THE PAC NW
STATES THAT WILL AFFECT OUR CWA IN SOME RESPECT THROUGH THE MIDDLE
OF NEXT WEEK.

.LONG TERM...TUESDAY THROUGH SATURDAY

UPPER LOW ALONG THE EASTERN END OF THE ALEUTIANS EARLY THIS MORNING
WILL DIG INTO THE EASTERN PACIFIC AND MOVE ONTO THE WEST COAST
TUESDAY MORNING...WITH UPPER TROUGH LIFTING ACROSS THE ROCKIES ON
WEDNESDAY.  ASSOCIATED SURFACE COLD FRONT WILL SLOWLY MOVE EAST
ACROSS IDAHO TUESDAY...INTO THE WEST TUESDAY AFTERNOON...AND ACROSS
CENTRAL WYOMING TUESDAY NIGHT.  ECMWF AND GFS SPREAD INCREASES AS
THE UPPER TROUGH CROSSES THE DIVIDE...THE ECMWF REMAINS QUICKER
BUILDING A RIDGE IN BEHIND THE TROUGH ON THURSDAY WHILE THE GFS
KEEPS A COOL UNSETTLED NW FLOW OVER THE AREA...BEFORE BUILDING THE
RIDGE IN THURSDAY NIGHT.  OPERATIONAL ECMWF IS SLIGHTLY FASTER THAN
THE EC ENSEMBLE MEAN WHILE THE GFS OPERATIONAL IS SLIGHTLY SLOWER
AND DEEPER THAN ITS ENSEMBLE MEAN.  SPLITTING THE DIFFERENCE WOULD
PUT THE UPPER TROUGH AXIS ROUGHLY ALONG 100W BY 00Z FRIDAY AND THE
UPSTREAM RIDGE ALONG 115W...WITH THIS RIDGE TRANSLATING THE AREA ON
FRIDAY AS NEXT PACIFIC TROUGH PUSHES ONTO THE WEST COAST.

FOR SENSIBLE WEATHER...

ON TUESDAY...VERY MILD AND WINDY CONDITIONS WILL DEVELOP ACROSS
CENTRAL AREAS AS PACIFIC COLD FRONT PUSHES ACROSS IDAHO WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE
WEST...SHOWERS AND ISOLATED STORMS SPREADING EAST LATE IN THE DAY.
SNOW LEVELS WILL REMAIN QUITE HIGH TUESDAY AHEAD OF THE
FRONT...GENERALLY AROUND 10KFT AND UP. RAPID SNOW MELT AND
SIGNIFICANT RISES IN CREEKS AND STREAMS WILL BE A CONCERN WITH THE
WARM TEMPERATURES...ESPECIALLY WITH THE POTENTIAL FOR RAIN NEAR
AND BELOW 10KFT.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...COLD FRONT WILL PUSH ACROSS THE
AREA SPREADING SHOWERS AND ISOLATED THUNDERSTORMS EAST OF THE DIVIDE
WITH SNOW LEVELS LOWERING TO THE VALLEY FLOORS IN THE WEST.  WNW
MOIST CYCLONIC FLOW ON BACKSIDE OF TROUGH LOOKS TO BRING SIGNIFICANT
SNOW ACCUMULATIONS FROM TETON...TOGWOTEE PASS NORTH TO YNP AND
THE BEARTOOTH PASS AREA WEDNESDAY AND WEDNESDAY NIGHT. GUSTY
DOWNSLOPE WEST WINDS WILL HINDER PRECIPITATION EAST OF THE DIVIDE
BEHIND THE COLD FRONT ON WEDNESDAY WITH THE BEST CHANCES OF RAIN
OR A RAIN AND SNOW MIX ACROSS THE NORTH AND SWEETWATER COUNTY.
HOWEVER...COLDER AND UNSTABLE NW FLOW PREVAIL BEHIND THE SYSTEM
WEDNESDAY NIGHT WITH SIGNIFICANT SNOW POSSIBLE IN THE BIGHORN
RANGE WITH POSSIBLY SOME HEAVIER CONVECTIVE SNOWBANDS FORMING IN
THE CENTRAL BASINS.

THURSDAY...FORECAST MAINTAINS CHANCES OF SNOW SHOWERS IN THE
NORTHERN MOUNTAINS WITH SLIGHT CHANCES OF RAIN/SNOW SHOWERS ACROSS
THE LOWER ELEVATIONS OF THE NORTH.  GUSTY W-NW WINDS AND SEASONABLY
COOL CONDITIONS OTHERWISE.

FRIDAY AND SATURDAY...WARMING TREND WITH BACKING SW FLOW AHEAD OF
NEXT PACIFIC TROUGH WITH INCREASING CHANCES OF SHOWERS IN THE
WEST...SLIGHT CHANCES OF SHOWERS EAST OF THE DIVIDE ON SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR CONDITIONS WITH ONLY FEW-SCT HIGH CLOUDS AND MAINLY LIGHT WINDS
ARE EXPECTED THROUGH THE FORECAST PERIOD. HOWEVER...SOME ISOLATED
SHOWERS OR EVEN A THUNDERSTORM COULD FORM IN SOUTHEAST SWEETWATER
COUNTY THIS AFTERNOON. WINDS WILL VEER TO THE NORTH DURING THE
COURSE OF THE AFTERNOON ON SUNDAY AS A WEAK FRONTAL BOUNDARY PUSHES
SOUTH OVER THE AREA.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

THERE IS THE POSSIBILITY OF ISOLATED CONVECTION SOUTH OF INTERSTATE
80. THIS ACTIVITY SHOULD REMAIN SOUTH OF THE KRKS TERMINAL...BUT THE
TERMINAL COULD SEE SOME OUTFLOW WINDS FROM THE ACTIVITY.
OTHERWISE...VFR CONDITIONS AND LIGHT WINDS ARE EXPECTED.

&&

.FIRE WEATHER...

TODAY...HIGH TEMPERATURES WILL BE WARM AND SEASONAL...WITH
MUCH LIGHTER WINDS THAN ON FRIDAY. ISOLATED CHANCES FOR MOSTLY DRY
SHOWERS OR AN ISOLATED THUNDERSTORM WILL BE POSSIBLE SOUTH OF A ROCK
SPRINGS TO CASPER LINE.  SUNDAY WILL BE SIMILAR IN MANY
RESPECTS...WITH HIGH TEMPERATURES A FEW DEGREES WARMER AND SLIGHT
CHANCES FOR SHOWERS A JUST BIT FURTHER NORTH. WINDS WILL BEGIN TO
SLOWLY INCREASE MONDAY NIGHT AS WILL CHANCES FOR PRECIPITATION IN
THE WESTERN MOUNTAIN ZONES...AS THE NEXT UPPER LEVEL DISTURBANCE
APPROACHES FROM THE WEST...HERALDING THE BEGINNING OF A COUPLE OF
DAYS OF PRECIPITATION OUT WEST. SIGNIFICANT MOUNTAIN SNOWS WILL BE
POSSIBLE STARTING TUESDAY NIGHT. OTHERWISE...WARM AND DRY ACROSS THE
CENTRAL AND SOUTHERN DISPATCH ZONES THROUGH TUESDAY NIGHT...WITH
WINDY CONDITIONS COMMENCING ACROSS ALL ZONES FROM TUESDAY NIGHT AND
LASTING THROUGH THURSDAY. THERE WILL BE SOME ENHANCED FIRE
DANGER...ESPECIALLY ON TUESDAY...AS THE WARMEST TEMPERATURE OF THE
SEASON COMBINE WITH THE STRONG WINDS. COOLER TEMPERATURES BOTH
WEDNESDAY AND THURSDAY WILL THEN MODERATE THE DANGER TO SOME
EXTENT.

&&

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

$$

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













000
FXUS65 KRIW 190941
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
341 AM MDT SAT APR 19 2014

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

WV IMAGERY STILL SHOWS PROGRESSIVE/FAST MOVING NRN BRANCH OF POLAR
FLOW ATOP SOMEWHAT SLOWER SRN BRANCH OF SUB-TROPICAL FLOW STRETCHING
ACROSS THE ENTIRE CONUS. THERE ARE NO LESS THAN 5 ACTIVE UPR LOWS
ENCOMPASSING THE CONUS...WITH EACH TRYING TO STEAL SOME THUNDER FROM
THE OTHER...KEEP ALL IN CHECK FOR THE MOST PART. HERE...UPR TROF
THRU WITH A COUPLE OF MOSTLY DRY FRONTS DRAPED ACROSS THE SRN AND
NRN FA. BENIGN HIGH PRESSURE WITH WEAK GRADIENT SLOWLY INFILTRATING
FROM THE NW...REIGNING IN THE WINDS FOR A WHILE ANYWAY.

GENERALLY...TODAY WILL BE SLIGHTLY COOLER THAN FRIDAY...WITH HIGH
TEMPS STILL REACHING INTO THE MIDDLE AND UPPER 60S FOR MOST OF THE
LOWER ELEVATIONS. OTHERWISE...NEARLY STATIONARY FRONT SET UP NEAR/
NORTH OF THE WY/CO BORDER IN OUR SRN MOST ZONES WILL AID IN RENEWED
CONVECTIVE DEVELOPMENT BY MID DAY IN A LARGELY DRY ADIABATIC
ATMOSPHERE. THIS AREA MAY LIFT FAR ENOUGH NORTH THAT SOME ACTIVITY
MAY PRESENT ITSELF OVR SRN NATRONA COUNTY TOO. WON`T HELP MUCH
HOWEVER AS CONVECTIVE MODE WILL HAVE LITTLE MOISTURE TO WORK
WITH...YIELDING MOSTLY DRY SHOWERS/STORMS WITH GUSTY WINDS.

SUNDAY WILL BE NICE OVERALL. THE AFTERNOON WILL OFFER LOW END
CHANCES FOR ISOLATED TO WIDELY SCATTERED SHOWERS WITH SOME THUNDER
AS A WEAK UPR LVL DISTURBANCE AND SFC FRONT RACE THROUGH THE FA.
TIMING AND MARGINALLY AVAILABLE MOISTURE WILL LIMIT THE CONVECTIVE
AREA TO OUR SRN AND SERN ZONES. HOWEVER...THIS WILL BE ANOTHER CASE
OF HIGH BASED SHOWERS/FEW STORMS WITH LITTLE RAIN...AND MORE GUSTY
WINDS. MONDAY THRU MOST OF THE DAY...UPR RIDGE AND STABLE ATMOSPHERE
IN PLACE. BY EVENING HOWEVER...RIDGE AXIS STARTS TO HEAD OUT WHILE
TROF FROM THE WEST BEGINS TO MOVE IN WITH PVA STARTING AS PART OF
POLAR JET...CURRENTLY HOVERING OVR THE EPAC REGION W OF
WA/OR...WORKS ITS WAY INTO THE WRN MOUNTAINS WITH A LITTLE MOISTURE.
THIS WILL HERALD THE BEGINNING OF NEW CYCLOGENESIS IN THE PAC NW
STATES THAT WILL AFFECT OUR CWA IN SOME RESPECT THROUGH THE MIDDLE
OF NEXT WEEK.

.LONG TERM...TUESDAY THROUGH SATURDAY

UPPER LOW ALONG THE EASTERN END OF THE ALEUTIANS EARLY THIS MORNING
WILL DIG INTO THE EASTERN PACIFIC AND MOVE ONTO THE WEST COAST
TUESDAY MORNING...WITH UPPER TROUGH LIFTING ACROSS THE ROCKIES ON
WEDNESDAY.  ASSOCIATED SURFACE COLD FRONT WILL SLOWLY MOVE EAST
ACROSS IDAHO TUESDAY...INTO THE WEST TUESDAY AFTERNOON...AND ACROSS
CENTRAL WYOMING TUESDAY NIGHT.  ECMWF AND GFS SPREAD INCREASES AS
THE UPPER TROUGH CROSSES THE DIVIDE...THE ECMWF REMAINS QUICKER
BUILDING A RIDGE IN BEHIND THE TROUGH ON THURSDAY WHILE THE GFS
KEEPS A COOL UNSETTLED NW FLOW OVER THE AREA...BEFORE BUILDING THE
RIDGE IN THURSDAY NIGHT.  OPERATIONAL ECMWF IS SLIGHTLY FASTER THAN
THE EC ENSEMBLE MEAN WHILE THE GFS OPERATIONAL IS SLIGHTLY SLOWER
AND DEEPER THAN ITS ENSEMBLE MEAN.  SPLITTING THE DIFFERENCE WOULD
PUT THE UPPER TROUGH AXIS ROUGHLY ALONG 100W BY 00Z FRIDAY AND THE
UPSTREAM RIDGE ALONG 115W...WITH THIS RIDGE TRANSLATING THE AREA ON
FRIDAY AS NEXT PACIFIC TROUGH PUSHES ONTO THE WEST COAST.

FOR SENSIBLE WEATHER...

ON TUESDAY...VERY MILD AND WINDY CONDITIONS WILL DEVELOP ACROSS
CENTRAL AREAS AS PACIFIC COLD FRONT PUSHES ACROSS IDAHO WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE
WEST...SHOWERS AND ISOLATED STORMS SPREADING EAST LATE IN THE DAY.
SNOW LEVELS WILL REMAIN QUITE HIGH TUESDAY AHEAD OF THE
FRONT...GENERALLY AROUND 10KFT AND UP. RAPID SNOW MELT AND
SIGNIFICANT RISES IN CREEKS AND STREAMS WILL BE A CONCERN WITH THE
WARM TEMPERATURES...ESPECIALLY WITH THE POTENTIAL FOR RAIN NEAR
AND BELOW 10KFT.

TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...COLD FRONT WILL PUSH ACROSS THE
AREA SPREADING SHOWERS AND ISOLATED THUNDERSTORMS EAST OF THE DIVIDE
WITH SNOW LEVELS LOWERING TO THE VALLEY FLOORS IN THE WEST.  WNW
MOIST CYCLONIC FLOW ON BACKSIDE OF TROUGH LOOKS TO BRING SIGNIFICANT
SNOW ACCUMULATIONS FROM TETON...TOGWOTEE PASS NORTH TO YNP AND
THE BEARTOOTH PASS AREA WEDNESDAY AND WEDNESDAY NIGHT. GUSTY
DOWNSLOPE WEST WINDS WILL HINDER PRECIPITATION EAST OF THE DIVIDE
BEHIND THE COLD FRONT ON WEDNESDAY WITH THE BEST CHANCES OF RAIN
OR A RAIN AND SNOW MIX ACROSS THE NORTH AND SWEETWATER COUNTY.
HOWEVER...COLDER AND UNSTABLE NW FLOW PREVAIL BEHIND THE SYSTEM
WEDNESDAY NIGHT WITH SIGNIFICANT SNOW POSSIBLE IN THE BIGHORN
RANGE WITH POSSIBLY SOME HEAVIER CONVECTIVE SNOWBANDS FORMING IN
THE CENTRAL BASINS.

THURSDAY...FORECAST MAINTAINS CHANCES OF SNOW SHOWERS IN THE
NORTHERN MOUNTAINS WITH SLIGHT CHANCES OF RAIN/SNOW SHOWERS ACROSS
THE LOWER ELEVATIONS OF THE NORTH.  GUSTY W-NW WINDS AND SEASONABLY
COOL CONDITIONS OTHERWISE.

FRIDAY AND SATURDAY...WARMING TREND WITH BACKING SW FLOW AHEAD OF
NEXT PACIFIC TROUGH WITH INCREASING CHANCES OF SHOWERS IN THE
WEST...SLIGHT CHANCES OF SHOWERS EAST OF THE DIVIDE ON SATURDAY.


&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

THE EXTENT OF STRATUS IN WAKE OF A COLD FRONT OVER NATRONA
COUNTY...POSSIBLY IMPACTING KCPR...REMAINS IN QUESTION EARLY THIS
MORNING. WHETHER OR NOT TO KEEP THE BKN020 FOR KCPR WILL BE DECIDED
CLOSE TO THE 12Z TAF ISSUANCE TIME. HOWEVER...WHAT STRATUS DOES FORM
SHOULD LIFT OR SCATTER OUT BY AROUND 15Z. OTHERWISE...VFR CONDITIONS
WITH ONLY FEW-SCT HIGH CLOUDS AND MAINLY LIGHT WINDS ARE EXPECTED
THROUGH THE FORECAST PERIOD.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG COULD OCCUR IN THE FAR WESTERN VALLEYS THIS MORNING WHERE
RAIN OCCURRED FRIDAY. OTHERWISE...THE MAIN AVIATION CONCERN WILL BE
THE POSSIBILITY OF ISOLATED CONVECTION SOUTH OF INTERSTATE 80. THIS
ACTIVITY SHOULD REMAIN SOUTH OF THE KRKS TERMINAL...BUT THE TERMINAL
COULD SEE SOME OUTFLOW WINDS FROM THE ACTIVITY. OTHERWISE...VFR
CONDITIONS AND LIGHT WINDS ARE EXPECTED.

&&

.FIRE WEATHER...

TODAY...HIGH TEMPERATURES WILL BE WARM AND SEASONAL...WITH
MUCH LIGHTER WINDS THAN ON FRIDAY. ISOLATED CHANCES FOR MOSTLY DRY
SHOWERS OR AN ISOLATED THUNDERSTORM WILL BE POSSIBLE SOUTH OF A ROCK
SPRINGS TO CASPER LINE.  SUNDAY WILL BE SIMILAR IN MANY
RESPECTS...WITH HIGH TEMPERATURES A FEW DEGREES WARMER AND SLIGHT
CHANCES FOR SHOWERS A JUST BIT FURTHER NORTH. WINDS WILL BEGIN TO
SLOWLY INCREASE MONDAY NIGHT AS WILL CHANCES FOR PRECIPITATION IN
THE WESTERN MOUNTAIN ZONES...AS THE NEXT UPPER LEVEL DISTURBANCE
APPROACHES FROM THE WEST...HERALDING THE BEGINNING OF A COUPLE OF
DAYS OF PRECIPITATION OUT WEST. SIGNIFICANT MOUNTAIN SNOWS WILL BE
POSSIBLE STARTING TUESDAY NIGHT. OTHERWISE...WARM AND DRY ACROSS THE
CENTRAL AND SOUTHERN DISPATCH ZONES THROUGH TUESDAY NIGHT...WITH
WINDY CONDITIONS COMMENCING ACROSS ALL ZONES FROM TUESDAY NIGHT AND
LASTING THROUGH THURSDAY. THERE WILL BE SOME ENHANCED FIRE
DANGER...ESPECIALLY ON TUESDAY...AS THE WARMEST TEMPERATURE OF THE
SEASON COMBINE WITH THE STRONG WINDS. COOLER TEMPERATURES BOTH
WEDNESDAY AND THURSDAY WILL THEN MODERATE THE DANGER TO SOME
EXTENT.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...WM
FIRE WEATHER...BRAUN










000
FXUS65 KRIW 190522
AFDRIW

AREA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE RIVERTON WY
1122 PM MDT FRI APR 18 2014

.SHORT TERM...TONIGHT AND SATURDAY

STRONG COLD FRONT MOVING TO NEAR THE CONTINENTAL DIVIDE ATTM WITH
STRONG SW WINDS AHEAD OF IT AND COLDER RAIN AND SNOW SHOWERS BEHIND
IT. COLD ENOUGH IN THE STAR VALLEY FOR A QUICK CHANGEOVER TO SNOW
WITH UP TO A QUICK INCH REPORTED. JACKSON VALLEY STAYED RAIN WITH
RAINFALL AMOUNTS GENERALLY BETWEEN .15 AND .30 INCHES. WINDS ARE
SURFACING EAST OF THE DIVIDE IN MANY AREAS WITH WIND GUSTS OF 40 TO
50 MPH IN QUITE A FEW AREAS AND LOCALIZED GUSTS BETWEEN 55 AND 60
MPH. SOME AREAS WILL FLIRT WITH OR BRIEFLY TOUCH HIGH WIND THROUGH
00Z OR A LITTLE LATER IN THE CENTRAL ZONES. SPS IS COVERING THESE
AREAS. THERE WILL BE A FEW RAIN SHOWERS WITH FROPA EAST OF THE
DIVIDE BUT THEY WILL BE JUST ISOLATED IN MANY AREAS WITH THE DRY
AIRMASS AHEAD OF IT. THE NORTHERN ZONES HOWEVER...HAVE A LITTLE LOW
LEVEL MOISTURE TO WORK WITH SO A BETTER SHOT THERE ALONG WITH AN
ISOLATED THUNDERSTORM STILL POSSIBLE BUT NOT NECESSARILY LIKELY.
SECONDARY FRONT THAT DROPS DOWN BEHIND THE WEAKENING UPPER
LOW/SHORTWAVE TONIGHT WITH BOUNDARY LAYER MOISTENING UP QUITE A BIT
IN NATRONA COUNTY. COULD BE ENOUGH FOR LOW CLOUDS OR PATCHY FOG SO
INDICATED THIS IN THE FORECAST AROUND SUNRISE. AND WITH THE RECENT
RAIN AND SNOW OUT WEST...WILL ADD SOME LOW CLOUDS AND FOG TO THE
JACKSON AND STAR VALLEYS FOR LATER TONIGHT THROUGH 15Z SATURDAY. ON
SATURDAY...SOME CONVECTION IS POSSIBLE ACROSS SWEETWATER COUNTY AS
FRONT BOUNDARY STALLS OUT DOWN THERE AND THEN A LITTLE BIT OF
MOISTURE AND VERY WEAK FORCING IS PROVIDED FROM A SYSTEM WELL TO OUR
SOUTH. SCATTERED HIGHER TERRAIN SHOWERS ARE CERTAINLY A
POSSIBILITY...MORE ISOLATED ON THE RED DESERT FLOOR. TEMPERATURES
WILL NOT BE QUITE AS WARM TOMORROW EAST OF THE DIVIDE WHILE WEST OF
THE DIVIDE...THEY`LL ACTUALLY BE WARMER WITHOUT THE PCPN.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE REST OF THE WEEKEND INTO MONDAY REMAINS RELATIVELY QUIET...WITH
A WEAK COLD FRONT MOVING THROUGH THE AREA SUNDAY MORNING. ISOLATED
SHOWERS AND AN ISOLATED THUNDERSTORM WILL BE POSSIBLE ACROSS
SOUTHERN PORTIONS SUNDAY...WITH DRY CONDITIONS ON MONDAY.

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE NORTHERN ROCKIES INTO
ALBERTA MONDAY...AND SLOWLY PROGRESS EASTWARD INTO THE HIGH PLAINS
TUESDAY...AS THE NEXT STORM SYSTEM FROM THE NORTH PACIFIC DIGS
SOUTHEASTWARD INTO NORTHERN CALIFORNIA AND THE GREAT BASIN. A
DUMBBELL LOW WILL FORM BY 12Z WEDNESDAY AND PROGRESS EASTWARD OVER
MONTANA...BEFORE EJECTING INTO THE NORTHERN PLAINS BY 18Z THURSDAY.
NORTHWEST FLOW ALOFT WILL OCCUR IN THE STORMS WAKE...AS A RIDGE OF
HIGH PRESSURE BUILDS BACK INTO THE AREA ON FRIDAY INTO SATURDAY. THE
12Z GFS AND ECMWF HAVE COME MORE IN LINE WITH EACH OTHER THAN
PREVIOUS RUNS. THIS IS A PROMISING SIGN FIVE DAYS OUT...SO WILL
CONTINUE TO MONITOR ANY CHANGES AS THE STORM APPROACHES SHORE.

ON TUESDAY...ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS WILL ENTER
WESTERN PORTIONS EARLY TUESDAY MORNING...INCREASING THROUGH THE DAY.
ISOLATED THUNDERSTORMS WILL BE POSSIBLE BY THE AFTERNOON ACROSS MOST
OF THE AREA...WITH MOST OF THE PRECIPITATION OCCURRING ACROSS
WESTERN...SOUTHWESTERN AND NORTHERN PORTIONS. SOUTHWEST FLOW ALOFT
WILL CREATE GUSTY WINDS DURING THE DAY AHEAD OF THE COLD FRONT
ACROSS CENTRAL AND SOUTHERN PORTIONS...AND PUSHING AFTERNOON
TEMPERATURES EAST OF THE DIVIDE INTO THE 70S AND POSSIBLY LOWER
80S.

ON WEDNESDAY...SNOW WILL FALL TUESDAY NIGHT INTO WEDNESDAY MORNING
ACROSS THE WESTERN MOUNTAINS AND THE HIGHER ELEVATIONS OF THE
BIGHORN MOUNTAINS. RAIN WILL SLOWLY CHANGE OVER TO SNOW ACROSS THE
WESTERN VALLEYS AND BASINS...BECOMING ALL SNOW SHORTLY BEFORE DAWN.
A RAIN/SNOW MIX WILL RETURN TO THESE AREAS BY LATE MORNING THROUGH
THE REST OF THE DAY. RAIN/SNOW SHOWERS WILL ALSO OCCUR ACROSS
SOUTHERN PORTIONS THROUGH MID MORNING BEFORE CHANGING OVER TO ALL
RAIN. THE REST OF THE AREA CAN EXPECT ISOLATED TO SCATTERED RAIN
SHOWERS THROUGH THE DAY.

ON THURSDAY...SNOW WILL CONTINUE ACROSS THE WEST...WITH A FEW
RAIN/SNOW SHOWERS MIXED IN LATER IN THE DAY. SNOW WILL FALL ACROSS
SOUTHERN PORTIONS...BECOMING MORE ISOLATED AND CHANGING TO RAIN BY
THE AFTERNOON. OVERALL...CHANCES FOR PRECIPITATION BECOME MORE
ISOLATED THROUGHOUT THE DAY.

BY FRIDAY...LINGERING ISOLATED SHOWERS ACROSS THE WEST.
OTHERWISE...COOLER AND DRY CONDITIONS.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

BREEZY WINDS IN A FEW LOCATIONS RIGHT NOW WILL CONTINUE TO WEAKEN
OVERNIGHT. SOME STRATUS IS EXPECTED TO DEVELOP OVER PORTIONS OF
JOHNSON AND NATRONA COUNTY IN WAKE OF A COLD FRONT LATER
TONIGHT...BUT THE EXTENT REMAINS IN QUESTION. HIGH RESOLUTION MODELS
CONTINUE TO SHOW BOUNDARY LAYER MOISTENING UP TO SUPPORT LOW CLOUDS
BETWEEN 09Z AND 12Z. WILL KEEP BKN020 FOR KCPR TERMINAL BETWEEN 12Z
AND 15Z...AND LATER FORECASTS CAN NUDGE AS NEED.
HOWEVER...WHAT STRATUS DOES FORM SHOULD LIFT OR SCATTER OUT BY
AROUND 15Z. OTHERWISE...VFR CONDITIONS WITH ONLY FEW-SCT HIGH CLOUDS
AND MAINLY LIGHT WINDS ARE EXPECTED SATURDAY AND SATURDAY EVENING.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG COULD OCCUR IN THE FAR WESTERN VALLEYS SATURDAY MORNING
WHERE RAIN OCCURRED YESTERDAY. OTHERWISE...THE MAIN AVIATION CONCERN
WILL BE THE POSSIBILITY OF ISOLATED CONVECTION SOUTH OF INTERSTATE
80 SATURDAY AFTERNOON. THIS ACTIVITY SHOULD REMAIN SOUTH OF THE KRKS
TERMINAL...BUT THE TERMINAL COULD SEE SOME OUTFLOW WINDS FROM THE
ACTIVITY. OTHERWISE...VFR CONDITIONS AND LIGHT WINDS ARE EXPECTED.

&&

.FIRE WEATHER...

A STRONG COLD FRONT WILL CONTINUE MOVING ACROSS CENTRAL WYOMING THIS
AFTERNOON WITH STRONG WEST TO SOUTHWEST WINDS OF 40 TO 50 MPH AND
ISOLATED TO WIDELY SCATTERED SHOWERS. THUNDERSTORMS...IF ANY...WILL
BE VERY ISOLATED AND MAINLY CONFINED TO THE NORTHEAST PART OF THE
DISTRICT. MOUNTAIN SNOW SHOWERS OUT WEST WILL DIMINISH AND RETREAT
TO THE HIGHER PEAKS WITH TIME TONIGHT. SATURDAY WILL NOT BE AS WINDY
BUT STILL BREEZY TO LOCALLY WINDY...ESPECIALLY THE MOUNTAIN AND
FOOTHILL AREAS. THERE WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS IN SWEETWATER COUNTY...ESPECIALLY SOUTH OF INTERSTATE
80 SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...SKRBAC
LONG TERM...LAVOIE
AVIATION...WM
FIRE WEATHER...SKRBAC

















000
FXUS65 KRIW 190519
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1118 PM MDT FRI APR 18 2014

.SHORT TERM...TONIGHT AND SATURDAY

STRONG COLD FRONT MOVING TO NEAR THE CONTINENTAL DIVIDE ATTM WITH
STRONG SW WINDS AHEAD OF IT AND COLDER RAIN AND SNOW SHOWERS BEHIND
IT. COLD ENOUGH IN THE STAR VALLEY FOR A QUICK CHANGEOVER TO SNOW
WITH UP TO A QUICK INCH REPORTED. JACKSON VALLEY STAYED RAIN WITH
RAINFALL AMOUNTS GENERALLY BETWEEN .15 AND .30 INCHES. WINDS ARE
SURFACING EAST OF THE DIVIDE IN MANY AREAS WITH WIND GUSTS OF 40 TO
50 MPH IN QUITE A FEW AREAS AND LOCALIZED GUSTS BETWEEN 55 AND 60
MPH. SOME AREAS WILL FLIRT WITH OR BRIEFLY TOUCH HIGH WIND THROUGH
00Z OR A LITTLE LATER IN THE CENTRAL ZONES. SPS IS COVERING THESE
AREAS. THERE WILL BE A FEW RAIN SHOWERS WITH FROPA EAST OF THE
DIVIDE BUT THEY WILL BE JUST ISOLATED IN MANY AREAS WITH THE DRY
AIRMASS AHEAD OF IT. THE NORTHERN ZONES HOWEVER...HAVE A LITTLE LOW
LEVEL MOISTURE TO WORK WITH SO A BETTER SHOT THERE ALONG WITH AN
ISOLATED THUNDERSTORM STILL POSSIBLE BUT NOT NECESSARILY LIKELY.
SECONDARY FRONT THAT DROPS DOWN BEHIND THE WEAKENING UPPER
LOW/SHORTWAVE TONIGHT WITH BOUNDARY LAYER MOISTENING UP QUITE A BIT
IN NATRONA COUNTY. COULD BE ENOUGH FOR LOW CLOUDS OR PATCHY FOG SO
INDICATED THIS IN THE FORECAST AROUND SUNRISE. AND WITH THE RECENT
RAIN AND SNOW OUT WEST...WILL ADD SOME LOW CLOUDS AND FOG TO THE
JACKSON AND STAR VALLEYS FOR LATER TONIGHT THROUGH 15Z SATURDAY. ON
SATURDAY...SOME CONVECTION IS POSSIBLE ACROSS SWEETWATER COUNTY AS
FRONT BOUNDARY STALLS OUT DOWN THERE AND THEN A LITTLE BIT OF
MOISTURE AND VERY WEAK FORCING IS PROVIDED FROM A SYSTEM WELL TO OUR
SOUTH. SCATTERED HIGHER TERRAIN SHOWERS ARE CERTAINLY A
POSSIBILITY...MORE ISOLATED ON THE RED DESERT FLOOR. TEMPERATURES
WILL NOT BE QUITE AS WARM TOMORROW EAST OF THE DIVIDE WHILE WEST OF
THE DIVIDE...THEY`LL ACTUALLY BE WARMER WITHOUT THE PCPN.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE REST OF THE WEEKEND INTO MONDAY REMAINS RELATIVELY QUIET...WITH
A WEAK COLD FRONT MOVING THROUGH THE AREA SUNDAY MORNING. ISOLATED
SHOWERS AND AN ISOLATED THUNDERSTORM WILL BE POSSIBLE ACROSS
SOUTHERN PORTIONS SUNDAY...WITH DRY CONDITIONS ON MONDAY.

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE NORTHERN ROCKIES INTO
ALBERTA MONDAY...AND SLOWLY PROGRESS EASTWARD INTO THE HIGH PLAINS
TUESDAY...AS THE NEXT STORM SYSTEM FROM THE NORTH PACIFIC DIGS
SOUTHEASTWARD INTO NORTHERN CALIFORNIA AND THE GREAT BASIN. A
DUMBBELL LOW WILL FORM BY 12Z WEDNESDAY AND PROGRESS EASTWARD OVER
MONTANA...BEFORE EJECTING INTO THE NORTHERN PLAINS BY 18Z THURSDAY.
NORTHWEST FLOW ALOFT WILL OCCUR IN THE STORMS WAKE...AS A RIDGE OF
HIGH PRESSURE BUILDS BACK INTO THE AREA ON FRIDAY INTO SATURDAY. THE
12Z GFS AND ECMWF HAVE COME MORE IN LINE WITH EACH OTHER THAN
PREVIOUS RUNS. THIS IS A PROMISING SIGN FIVE DAYS OUT...SO WILL
CONTINUE TO MONITOR ANY CHANGES AS THE STORM APPROACHES SHORE.

ON TUESDAY...ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS WILL ENTER
WESTERN PORTIONS EARLY TUESDAY MORNING...INCREASING THROUGH THE DAY.
ISOLATED THUNDERSTORMS WILL BE POSSIBLE BY THE AFTERNOON ACROSS MOST
OF THE AREA...WITH MOST OF THE PRECIPITATION OCCURRING ACROSS
WESTERN...SOUTHWESTERN AND NORTHERN PORTIONS. SOUTHWEST FLOW ALOFT
WILL CREATE GUSTY WINDS DURING THE DAY AHEAD OF THE COLD FRONT
ACROSS CENTRAL AND SOUTHERN PORTIONS...AND PUSHING AFTERNOON
TEMPERATURES EAST OF THE DIVIDE INTO THE 70S AND POSSIBLY LOWER
80S.

ON WEDNESDAY...SNOW WILL FALL TUESDAY NIGHT INTO WEDNESDAY MORNING
ACROSS THE WESTERN MOUNTAINS AND THE HIGHER ELEVATIONS OF THE
BIGHORN MOUNTAINS. RAIN WILL SLOWLY CHANGE OVER TO SNOW ACROSS THE
WESTERN VALLEYS AND BASINS...BECOMING ALL SNOW SHORTLY BEFORE DAWN.
A RAIN/SNOW MIX WILL RETURN TO THESE AREAS BY LATE MORNING THROUGH
THE REST OF THE DAY. RAIN/SNOW SHOWERS WILL ALSO OCCUR ACROSS
SOUTHERN PORTIONS THROUGH MID MORNING BEFORE CHANGING OVER TO ALL
RAIN. THE REST OF THE AREA CAN EXPECT ISOLATED TO SCATTERED RAIN
SHOWERS THROUGH THE DAY.

ON THURSDAY...SNOW WILL CONTINUE ACROSS THE WEST...WITH A FEW
RAIN/SNOW SHOWERS MIXED IN LATER IN THE DAY. SNOW WILL FALL ACROSS
SOUTHERN PORTIONS...BECOMING MORE ISOLATED AND CHANGING TO RAIN BY
THE AFTERNOON. OVERALL...CHANCES FOR PRECIPITATION BECOME MORE
ISOLATED THROUGHOUT THE DAY.

BY FRIDAY...LINGERING ISOLATED SHOWERS ACROSS THE WEST.
OTHERWISE...COOLER AND DRY CONDITIONS.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

BREEZY WINDS IN A FEW LOCATIONS RIGHT NOW WILL CONTINUE TO WEAKEN
OVERNIGHT. SOME STRATUS IS EXPECTED TO DEVELOP OVER PORTIONS OF
JOHNSON AND NATRONA COUNTY IN WAKE OF A COLD FRONT LATER
TONIGHT...BUT THE EXTENT REMAINS IN QUESTION. HIGH RESOLUTION MODELS
CONTINUE TO SHOW BOUNDARY LAYER MOISTENING UP TO SUPPORT LOW CLOUDS
BETWEEN 09Z AND 12Z. WILL KEEP BKN020 FOR KCPR TERMINAL BETWEEN 12Z
AND 15Z...AND LATER FORECASTS CAN NUDGE AS NEED.
HOWEVER...WHAT STRATUS DOES FORM SHOULD LIFT OR SCATTER OUT BY
AROUND 15Z. OTHERWISE...VFR CONDITIONS WITH ONLY FEW-SCT HIGH CLOUDS
AND MAINLY LIGHT WINDS ARE EXPECTED SATURDAY AND SATURDAY EVENING.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG COULD OCCUR IN THE FAR WESTERN VALLEYS SATURDAY MORNING
WHERE RAIN OCCURRED YESTERDAY. OTHERWISE...THE MAIN AVIATION CONCERN
WILL BE THE POSSIBILITY OF ISOLATED CONVECTION SOUTH OF INTERSTATE
80 SATURDAY AFTERNOON. THIS ACTIVITY SHOULD REMAIN SOUTH OF THE KRKS
TERMINAL...BUT THE TERMINAL COULD SEE SOME OUTFLOW WINDS FROM THE
ACTIVITY. OTHERWISE...VFR CONDITIONS AND LIGHT WINDS ARE EXPECTED.

&&

.FIRE WEATHER...

A STRONG COLD FRONT WILL CONTINUE MOVING ACROSS CENTRAL WYOMING THIS
AFTERNOON WITH STRONG WEST TO SOUTHWEST WINDS OF 40 TO 50 MPH AND
ISOLATED TO WIDELY SCATTERED SHOWERS. THUNDERSTORMS...IF ANY...WILL
BE VERY ISOLATED AND MAINLY CONFINED TO THE NORTHEAST PART OF THE
DISTRICT. MOUNTAIN SNOW SHOWERS OUT WEST WILL DIMINISH AND RETREAT
TO THE HIGHER PEAKS WITH TIME TONIGHT. SATURDAY WILL NOT BE AS WINDY
BUT STILL BREEZY TO LOCALLY WINDY...ESPECIALLY THE MOUNTAIN AND
FOOTHILL AREAS. THERE WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS IN SWEETWATER COUNTY...ESPECIALLY SOUTH OF INTERSTATE
80 SATURDAY AFTERNOON.

&&

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

&&

$$

SHORT TERM...SKRBAC
LONG TERM...LAVOIE
AVIATION...WM
FIRE WEATHER...SKRBAC














000
FXUS65 KRIW 182049
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
249 PM MDT FRI APR 18 2014

.SHORT TERM...TONIGHT AND SATURDAY

STRONG COLD FRONT MOVING TO NEAR THE CONTINENTAL DIVIDE ATTM WITH
STRONG SW WINDS AHEAD OF IT AND COLDER RAIN AND SNOW SHOWERS BEHIND
IT. COLD ENOUGH IN THE STAR VALLEY FOR A QUICK CHANGEOVER TO SNOW
WITH UP TO A QUICK INCH REPORTED. JACKSON VALLEY STAYED RAIN WITH
RAINFALL AMOUNTS GENERALLY BETWEEN .15 AND .30 INCHES. WINDS ARE
SURFACING EAST OF THE DIVIDE IN MANY AREAS WITH WIND GUSTS OF 40 TO
50 MPH IN QUITE A FEW AREAS AND LOCALIZED GUSTS BETWEEN 55 AND 60
MPH. SOME AREAS WILL FLIRT WITH OR BRIEFLY TOUCH HIGH WIND THROUGH
00Z OR A LITTLE LATER IN THE CENTRAL ZONES. SPS IS COVERING THESE
AREAS. THERE WILL BE A FEW RAIN SHOWERS WITH FROPA EAST OF THE
DIVIDE BUT THEY WILL BE JUST ISOLATED IN MANY AREAS WITH THE DRY
AIRMASS AHEAD OF IT. THE NORTHERN ZONES HOWEVER...HAVE A LITTLE LOW
LEVEL MOISTURE TO WORK WITH SO A BETTER SHOT THERE ALONG WITH AN
ISOLATED THUNDERSTORM STILL POSSIBLE BUT NOT NECESSARILY LIKELY.
SECONDARY FRONT THAT DROPS DOWN BEHIND THE WEAKENING UPPER
LOW/SHORTWAVE TONIGHT WITH BOUNDARY LAYER MOISTENING UP QUITE A BIT
IN NATRONA COUNTY. COULD BE ENOUGH FOR LOW CLOUDS OR PATCHY FOG SO
INDICATED THIS IN THE FORECAST AROUND SUNRISE. AND WITH THE RECENT
RAIN AND SNOW OUT WEST...WILL ADD SOME LOW CLOUDS AND FOG TO THE
JACKSON AND STAR VALLEYS FOR LATER TONIGHT THROUGH 15Z SATURDAY. ON
SATURDAY...SOME CONVECTION IS POSSIBLE ACROSS SWEETWATER COUNTY AS
FRONT BOUNDARY STALLS OUT DOWN THERE AND THEN A LITTLE BIT OF
MOISTURE AND VERY WEAK FORCING IS PROVIDED FROM A SYSTEM WELL TO OUR
SOUTH. SCATTERED HIGHER TERRAIN SHOWERS ARE CERTAINLY A
POSSIBILITY...MORE ISOLATED ON THE RED DESERT FLOOR. TEMPERATURES
WILL NOT BE QUITE AS WARM TOMORROW EAST OF THE DIVIDE WHILE WEST OF
THE DIVIDE...THEY`LL ACTUALLY BE WARMER WITHOUT THE PCPN.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE REST OF THE WEEKEND INTO MONDAY REMAINS RELATIVELY QUIET...WITH
A WEAK COLD FRONT MOVING THROUGH THE AREA SUNDAY MORNING. ISOLATED
SHOWERS AND AN ISOLATED THUNDERSTORM WILL BE POSSIBLE ACROSS
SOUTHERN PORTIONS SUNDAY...WITH DRY CONDITIONS ON MONDAY.

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE NORTHERN ROCKIES INTO
ALBERTA MONDAY...AND SLOWLY PROGRESS EASTWARD INTO THE HIGH PLAINS
TUESDAY...AS THE NEXT STORM SYSTEM FROM THE NORTH PACIFIC DIGS
SOUTHEASTWARD INTO NORTHERN CALIFORNIA AND THE GREAT BASIN. A
DUMBBELL LOW WILL FORM BY 12Z WEDNESDAY AND PROGRESS EASTWARD OVER
MONTANA...BEFORE EJECTING INTO THE NORTHERN PLAINS BY 18Z THURSDAY.
NORTHWEST FLOW ALOFT WILL OCCUR IN THE STORMS WAKE...AS A RIDGE OF
HIGH PRESSURE BUILDS BACK INTO THE AREA ON FRIDAY INTO SATURDAY. THE
12Z GFS AND ECMWF HAVE COME MORE IN LINE WITH EACH OTHER THAN
PREVIOUS RUNS. THIS IS A PROMISING SIGN FIVE DAYS OUT...SO WILL
CONTINUE TO MONITOR ANY CHANGES AS THE STORM APPROACHES SHORE.

ON TUESDAY...ISOLATED TO SCATTERED RAIN AND SNOW SHOWERS WILL ENTER
WESTERN PORTIONS EARLY TUESDAY MORNING...INCREASING THROUGH THE DAY.
ISOLATED THUNDERSTORMS WILL BE POSSIBLE BY THE AFTERNOON ACROSS MOST
OF THE AREA...WITH MOST OF THE PRECIPITATION OCCURRING ACROSS
WESTERN...SOUTHWESTERN AND NORTHERN PORTIONS. SOUTHWEST FLOW ALOFT
WILL CREATE GUSTY WINDS DURING THE DAY AHEAD OF THE COLD FRONT
ACROSS CENTRAL AND SOUTHERN PORTIONS...AND PUSHING AFTERNOON
TEMPERATURES EAST OF THE DIVIDE INTO THE 70S AND POSSIBLY LOWER
80S.

ON WEDNESDAY...SNOW WILL FALL TUESDAY NIGHT INTO WEDNESDAY MORNING
ACROSS THE WESTERN MOUNTAINS AND THE HIGHER ELEVATIONS OF THE
BIGHORN MOUNTAINS. RAIN WILL SLOWLY CHANGE OVER TO SNOW ACROSS THE
WESTERN VALLEYS AND BASINS...BECOMING ALL SNOW SHORTLY BEFORE DAWN.
A RAIN/SNOW MIX WILL RETURN TO THESE AREAS BY LATE MORNING THROUGH
THE REST OF THE DAY. RAIN/SNOW SHOWERS WILL ALSO OCCUR ACROSS
SOUTHERN PORTIONS THROUGH MID MORNING BEFORE CHANGING OVER TO ALL
RAIN. THE REST OF THE AREA CAN EXPECT ISOLATED TO SCATTERED RAIN
SHOWERS THROUGH THE DAY.

ON THURSDAY...SNOW WILL CONTINUE ACROSS THE WEST...WITH A FEW
RAIN/SNOW SHOWERS MIXED IN LATER IN THE DAY. SNOW WILL FALL ACROSS
SOUTHERN PORTIONS...BECOMING MORE ISOLATED AND CHANGING TO RAIN BY
THE AFTERNOON. OVERALL...CHANCES FOR PRECIPITATION BECOME MORE
ISOLATED THROUGHOUT THE DAY.

BY FRIDAY...LINGERING ISOLATED SHOWERS ACROSS THE WEST.
OTHERWISE...COOLER AND DRY CONDITIONS.

&&

.AVIATION.../00Z ISSUANCE/

COLD FRONT WILL MOVE QUICKLY EAST OF THE DIVIDE THROUGH EVENING
HOURS WITH A LOT OF WIND AND A FEW SHOWERS AND EVEN AN ISOLATED
THUNDERSTORM POSSIBLE. SCATTERED MOUNTAIN OBSCURATION AND SNOW
SHOWERS WILL PERSIST OUT WEST INTO THE EVENING BEFORE RETREATING TO
THE HIGHER PEAKS. LOW CLOUDS AND PATCHY FOG MAY FORM IN THE JACKSON
AND STAR VALLEYS OVERNIGHT AFFECTING THE KJAC TERMINAL WITH MVFR
CONDITIONS. ANOTHER AREA OF LOW CLOUDS AND FOG MAY FORM OVER NATRONA
COUNTY BY LATER TONIGHT AFFECTING THE KCPR TERMINAL BY SUNRISE.
OTHERWISE...EXPECT VFR CONDITIONS IN MOST AREAS WITH WINDS
DECREASING LATER TONIGHT. ON SATURDAY...SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE EXPECTED IN THE FAR SOUTH INCLUDING KRKS.
OTHER AREAS WILL BE DRY WITH VFR CONDITIONS AND LESS WIND. STILL
BREEZY TO LOCALLY WINDY BUT NOT AS STRONG AS TODAY.

&&

.FIRE WEATHER...

A STRONG COLD FRONT WILL CONTINUE MOVING ACROSS CENTRAL WYOMING THIS
AFTERNOON WITH STRONG WEST TO SOUTHWEST WINDS OF 40 TO 50 MPH AND
ISOLATED TO WIDELY SCATTERED SHOWERS. THUNDERSTORMS...IF ANY...WILL
BE VERY ISOLATED AND MAINLY CONFINED TO THE NORTHEAST PART OF THE
DISTRICT. MOUNTAIN SNOW SHOWERS OUT WEST WILL DIMINISH AND RETREAT
TO THE HIGHER PEAKS WITH TIME TONIGHT. SATURDAY WILL NOT BE AS WINDY
BUT STILL BREEZY TO LOCALLY WINDY...ESPECIALLY THE MOUNTAIN AND
FOOTHILL AREAS. THERE WILL BE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS IN SWEETWATER COUNTY...ESPECIALLY SOUTH OF INTERSTATE
80 SATURDAY AFTERNOON.

&&

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

&&

$$

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











000
FXUS65 KRIW 181753
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1153 AM MDT FRI APR 18 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

WV IMAGERY SHOWS COMPLEX BUT MOSTLY TAME UPR LVLS...WITH LOW AMPLITUDE
TROF RIDGE TROF PATTERN ACROSS THE NRN CONUS...LYING OVR TOP OF SUB
TROPICAL BASED TROF RIDGE TROF. WEAK CLOSED LOW ANCHORS THE SRN
PORTION OF THE W COAST TROF. THE NRN BRANCH OF THE UPR LVLS IS
MOVING FASTER THAN THE SRN BRANCH. RIDGE CURRENTLY OVR WY WILL GIVE
WAY TO THE QUICK MOVING TROF TO THE WEST. HOWEVER...MOISTURE
ASSOCIATED WITH THE WRN TROF IS MODEST FOR THE MOST PART DUE IN PART
TO ITS QUICK MOVEMENT WITH THE BEST WV CURRENTLY LOADED TO OUR W AND
NW...ASSOCIATED W/BAROCLINIC LEAF IN THE PAC NW...STARTING TO BE
RAPPED INTO WHAT WILL BE A RAPIDLY DEVELOPING CYCLONE WELL TO OUR N
NEAR THE NRN ID/CA BORDER. ADDITIONALLY...THERE IS JET PHASING GOING
ON NOW AS A PRECURSOR TO RAPID CYCLOGENESIS. THE SFC IS CURRENTLY
REPRESENTED BY A BROAD LOW CENTERED NEAR N CNTRL MT OUT IN FRONT OF
THE WRN TROF...W/ A LEE SIDE TROF NOW EXTENDING DOWN INTO OUR ERN
FA.

TODAY...THE PROBLEM WITH THIS MULTI-PART UPR SYSTEM IS THAT INSTEAD
OF FOCUSING ALL DYNAMICS FOR THE DEVELOPMENT OF ONE LARGE DEEP
BRUTAL SYSTEM...THE LOWER LVLS ARE GOING TO BE BUSY STRETCHING AND
TRYING TO SPIN UP AT LEAST THREE LOW PRESSURE SYSTEMS OVR THE NEXT
COUPLE OF DAYS...FROM N OF THE BORDER...S INTO THE SRN PLAINS. THE
AVAILABLE MOISTURE COMING IN FROM THE WEST WILL ALSO GET DIVVIED UP
WITH THE BEST WV HEADING UP NORTH WITH THE STRONGEST DEVELOPING
CYCLONE AND THE REST MOSTLY MISSING US SOUTH ON SATURDAY AS THE
OTHER LEE CYCLONE DEVELOPS. OUR WRN MOUNTAINS WILL FOR A SHORT
PERIOD BE IN DECENT POSITION THIS MORNING THRU MID AFTERNOON FOR
OROGRAPHICALLY INDUCED PRECIP. BY THIS AFTERNOON...LOW LVLS WILL
WARM ENOUGH...WITH SFC HIGHS E OF THE DIVIDE...APPROACHING OR JUST
CRESTING THE 70 DEG MARK IN THE BASINS AND EAST...TO CREATE SOME
INSTABILITY LATE THIS AFTERNOON AND EARLY EVENING. HOWEVER...EVEN
WITH BEST UPR FORCING FROM JET THIS AFTERNOON/EVENING...MEAGER
MOISTURE WILL SEVERELY LIMIT CONVECTIVE DEVELOPMENT FOR MOST AREAS.
THE BEST CHANCE FOR ISOLATED THUNDER E OF THE DIVIDE WILL ALL BE
ABOUT THE TIMING...AND WILL TAKE A FRONT...SOME BRIEF SHALLOW
MOISTURE POOLING NEAR NEAR THE FRONT...AND PROBABLY SOME NEARBY
TERRAIN TO LEND A HELPING HAND. ATTM...THE BEST LOCATION APPEARS TO
BE IN THE BIG HORN BASIN...WITH THE FAR SOUTHERN PORTION MOST
FAVORABLE...ALONG THE OWL CREEK AND BRIDGER MOUNTAINS...NORTH TO
PERHAPS THERMOPOLIS AND/OR WORLAND. MOSTLY DRY ADIABATIC ATMOSPHERE
SOUTH AND EAST OF THE THE BIG HORN BASIN WILL ONLY BE SLIGHTLY
UNSTABLE EVEN WITH RELATIVELY HIGH LAPSE RATES...AND THE WINDOW
SHORT FOR CONVECTION TO GET THRU. DIFFICULT TO ASCERTAIN WHERE THE
NAM IS/WAS GETTING THE RELATIVELY HIGH BL MOISTURE IN A SW FLOW
REGIME FOR NATRONA COUNTY...GENERATING RATHER LARGE CAPE. IT HAS
TONED DOWN SOME IN TONIGHTS RUN...BUT STILL SHOWS IT TO SOME
DEGREE...ALBEIT UNDER FAIRLY WELL CAPPED SKIES. OVERALL...JUST
DOESN`T LOOK ALL THAT PROMISING. STILL HAVE LOW POPS FOR LATE
AFTERNOON/EVE JUST IN CASE...WITH VIRGA THE MOSTLY LIKELY MAIN EVENT
FOR MUCH OF THE AREA. 2 INCHES OF WET SNOW AT BEST IN ISOLATED
LOCATIONS IN THE WRN MOUNTAINS...WITH MOST LOCATIONS GETTING HALF
THAT WITH SEASONALLY WARM CONDITIONS. OTHERWISE...THE SFC TO MID LVL
P AND T PATTERN WILL FAVOR INCREASED WINDS THRU THE DAY. HOWEVER IT
STILL APPEARS THAT ONLY VERY ISOLATED HIGH WIND CONDITIONS WILL
MANIFEST...IF AT ALL. JUST NOT ENOUGH CONFIDENCE TO WARN FOR THIS.

SATURDAY WILL BE SOMEWHAT COOLER N OF THE FRONT...BUT NOTHING
TOO DRASTIC WITH HIGH TEMPS STILL REACHING INTO THE MIDDLE 60S FOR
MANY LOW ELEVATION LOCALS...AND ALL WITH LESS WIND THAN FRIDAY. AS A
WEAK PRESSURE GRAD FILLS IN. STALLED FRONT NEAR AND JUST NORTH OF
THE WY/CO BORDER WILL ALLOW FOR SOME CONTINUED CONVECTIVE
DEVELOPMENT...ESPECIALLY BY MID DAY...AND MAY PUSH UP TO THE VERY
SRN REACHES OF NATRONA COUNTY. SUNDAY AFTERNOON WILL OFFER THE NEXT
BEST CHANCE FOR ISOLATED TO WIDELY SCATTERED SHOWERS WITH SOME
THUNDER AS LOW LEVELS WARM (NEAR 70S AGAIN) AND A WEAK UPR
DISTURBANCE MOVES THROUGH WHILE A WEAK CLIPPER TYPE FRONT BRUSHES
OUR ERN ZONES. GENERALLY 30 PERCENT OF LESS POPS FOR THIS
PERIOD.

.LONG TERM...MONDAY THROUGH FRIDAY

OUR MAIN WEATHER MAKER DURING THIS PERIOD WILL BE AN UPPER LOW
WOBBLING ITS WAY EASTWARD ALONG THE ALEUTIAN ISLANDS EARLY THIS
MORNING.  THIS SYSTEM WILL TAKE THE FORM OF AN UPRIGHT TROUGH ALONG
130W BY 00Z TUESDAY...PUMPING UP A RIDGE ACROSS THE ROCKIES.  THIS
WILL BRING DRY AND MILD CONDITIONS ON MONDAY.

TROUGH BECOMES MORE NEGATIVELY TILTED AS IT PUSHES INTO THE
INTERMOUNTAIN WEST ON TUESDAY AND THEN THE FUN BEGINS.  18/00Z ECMWF
IS MUCH MORE PROGRESSIVE THAN EARLIER RUNS...SWINGING THE UPPER
TROUGH ACROSS THE ROCKIES ON WEDNESDAY AND INTO THE PLAINS WEDNESDAY
NIGHT...SHORTWAVE RIDGE BUILDING IN THURSDAY MORNING.  THOUGH
GFS/GEFS MEAN HAVE ALSO TRENDED MORE PROGRESSIVE...THE DETERMINISTIC
CONTINUES BRIEFLY STALL OUT A CLOSED UPPER LOW OVER MONTANA ON
WEDNESDAY BEFORE PUSHING THE WHOLE MESSY TROUGH OUT INTO THE PLAINS
THURSDAY NIGHT.  THESE DIFFERENCES ALSO TRANSLATE INTO SUBSTANTIAL
SPREAD UPSTREAM WITH ECMWF BRINGING NEXT PACIFIC SYSTEM ONSHORE ON
FRIDAY WHILE GFS KEEPS THE SYSTEM OFF THE COAST.   ECMWF
DETERMINISTIC IS IN OVERALL AGREEMENT WITH THE EC EM...THE GFS IS ON
THE SLOW END OF ITS ENSEMBLE MEMBERS.

GIVEN THE ONGOING RUN-TO-RUN INCONSISTENCIES...THE FORECAST GIVES
THE MOST WEIGHT TO CONTINUITY.

ON TUESDAY...VERY MILD AND WINDY CONDITIONS WILL DEVELOP ACROSS
CENTRAL AREAS AS PACIFIC COLD FRONT PUSHES ACROSS IDAHO WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE
WEST...ISOLATED STORMS SPREADING EAST LATE IN THE DAY.  SNOW LEVELS
WILL REMAIN QUITE HIGH TUESDAY AHEAD OF THE FRONT...GENERALLY AROUND
10KFT AND UP.   RAPID SNOW MELT AND SIGNIFICANT RISES IN CREEKS AND
STREAMS WILL BE A CONCERN WITH THE WARM TEMPERATURES...ESPECIALLY
WITH THE POTENTIAL FOR RAIN NEAR AND BELOW 10KFT.

ON TUESDAY NIGHT AND WEDNESDAY...COLD FRONT WILL PUSH ACROSS THE
AREA SPREADING SHOWERS AND ISOLATED THUNDERSTORMS EAST OF THE DIVIDE
WITH SNOW LEVELS LOWERING TO THE VALLEY FLOORS IN THE WEST.
PRECIPITATION LOOKS TO BE MAINLY RAIN OR A RAIN/SNOW MIX ACROSS THE
CENTRAL BASINS THROUGH THE DAY.

THURSDAY AND FRIDAY...FORECAST MAINTAINS CHANCES OF MOUNTAIN SNOW
SHOWERS WITH SLIGHT CHANCES OF RAIN/SNOW SHOWERS IN THE VALLEYS AND
BASINS DURING THIS PERIOD WITH UNCERTAINTY ON HOW FAST THIS TROUGH
WILL EXIT AND THE NEXT ONE ARRIVES.

&&

.AVIATION.../18Z ISSUANCE/

A STORM SYSTEM AND ASSOCIATED COLD FRONT PASSING THROUGH THE COWBOY
STATE WILL RESULT IN SCATTERED TO LOCALLY NUMEROUS MOUNTAIN
SNOW/VALLEY RAIN SHOWERS...MAINLY ALONG AND NORTHWEST OF A
KAFO...KPNA...KDUB...KCOD LINE THROUGH THIS AFTERNOON. THE MOST
NUMEROUS RAIN AND SNOW SHOWERS WILL BE IN THE WEST THROUGH EARLY
AFTERNOON WITH MORE ISOLATED COVERAGE EAST OF THE DIVIDE MAINLY
LATER THIS AFTERNOON AND EARLY EVENING WITH ONLY A SMALL CHANCE OF
A THUNDERSTORM EAST OF THE DIVIDE. MOUNTAIN OBSCURATIONS WILL BE
PREVALENT WEST OF THE DIVIDE WITH THESE MOUNTAIN SNOW SHOWERS WITH
SOME VALLEY MVFR AFFECTING KJAC THROUGH ABOUT 20Z. IT WILL BE
WINDY IN MANY AREAS WITH POSSIBLE LLWS AT KLND AND KCOD.
CONDITIONS WILL IMPROVE TONIGHT WITH JUST A FEW LINGERING MOUNTAIN
SNOW SHOWERS. ANOTHER SYSTEM WILL AID IN AFTERNOON SHOWERS AND
ISOLATED THUNDERSTORMS IN THE FAR SOUTH POSSIBLY AFFECTING KRKS
SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

TODAY...THE BASIN ZONES WILL CLIMB NEAR OR INTO THE LOWER 70S...AHEAD OF
THE NEXT SPRING WEATHER SYSTEM DUE TO PUSH THROUGH THE FORECAST AREA
THROUGH THE DAY. MOUNTAIN INDUCED RAIN/SNOW CHANCES WILL INCREASE
THROUGH THE MORNING AND AFTERNOON HOURS... LASTING INTO THE EARLY
EVENING. HOWEVER...NEW SNOWFALL ACCUMULATIONS LOOK TO REMAIN ON THE
LOW SIDE WITH AN INCH OR TWO OF WET SNOW AT BEST. WINDS WILL ALSO
PICK UP TO THE BREEZY CATEGORY ACROSS MOST OF THE FORECAST
ZONES...WITH THE USUAL WIND PRONE AREAS OF THE SOUTHERN DISPATCH
ZONES...MOUNTAIN RIDGE TOPS AND NORTHERN CODY FOOTHILLS POSSIBLY
GETTING SOME ISOLATED HIGH WINDS. IN ADDITION...BY THIS AFTERNOON
THERE WILL BE AN INCREASING CHANCES FOR GUSTY LIGHT SHOWERS AND
PERHAPS AN ISOLATED THUNDERSTORM LASTING INTO THE EVENING PERIOD.
SATURDAY...HIGH TEMPERATURES WILL BE SEASONAL...AND THE WINDS  MORE
TAME...WITH ISOLATED TO WIDELY SCATTERED CHANCES FOR SHOWERS OR AN
ISOLATED THUNDERSTORM SUNDAY AFTERNOON...MAINLY EAST OF THE
DIVIDE.

&&

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

&&

$$

UPDATE...SKRBAC
SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...WM
FIRE WEATHER...BRAUN











000
FXUS65 KRIW 180944
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
344 AM MDT FRI APR 18 2014

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

WV IMAGERY SHOWS COMPLEX BUT MOSTLY TAME UPR LVLS...WITH LOW AMPLITUDE
TROF RIDGE TROF PATTERN ACROSS THE NRN CONUS...LYING OVR TOP OF SUB
TROPICAL BASED TROF RIDGE TROF. WEAK CLOSED LOW ANCHORS THE SRN
PORTION OF THE W COAST TROF. THE NRN BRANCH OF THE UPR LVLS IS
MOVING FASTER THAN THE SRN BRANCH. RIDGE CURRENTLY OVR WY WILL GIVE
WAY TO THE QUICK MOVING TROF TO THE WEST. HOWEVER...MOISTURE
ASSOCIATED WITH THE WRN TROF IS MODEST FOR THE MOST PART DUE IN PART
TO ITS QUICK MOVEMENT WITH THE BEST WV CURRENTLY LOADED TO OUR W AND
NW...ASSOCIATED W/BAROCLINIC LEAF IN THE PAC NW...STARTING TO BE
RAPPED INTO WHAT WILL BE A RAPIDLY DEVELOPING CYCLONE WELL TO OUR N
NEAR THE NRN ID/CA BORDER. ADDITIONALLY...THERE IS JET PHASING GOING
ON NOW AS A PRECURSOR TO RAPID CYCLOGENESIS. THE SFC IS CURRENTLY
REPRESENTED BY A BROAD LOW CENTERED NEAR N CNTRL MT OUT IN FRONT OF
THE WRN TROF...W/ A LEE SIDE TROF NOW EXTENDING DOWN INTO OUR ERN
FA.

TODAY...THE PROBLEM WITH THIS MULTI-PART UPR SYSTEM IS THAT INSTEAD
OF FOCUSING ALL DYNAMICS FOR THE DEVELOPMENT OF ONE LARGE DEEP
BRUTAL SYSTEM...THE LOWER LVLS ARE GOING TO BE BUSY STRETCHING AND
TRYING TO SPIN UP AT LEAST THREE LOW PRESSURE SYSTEMS OVR THE NEXT
COUPLE OF DAYS...FROM N OF THE BORDER...S INTO THE SRN PLAINS. THE
AVAILABLE MOISTURE COMING IN FROM THE WEST WILL ALSO GET DIVVIED UP
WITH THE BEST WV HEADING UP NORTH WITH THE STRONGEST DEVELOPING
CYCLONE AND THE REST MOSTLY MISSING US SOUTH ON SATURDAY AS THE
OTHER LEE CYCLONE DEVELOPS. OUR WRN MOUNTAINS WILL FOR A SHORT
PERIOD BE IN DECENT POSITION THIS MORNING THRU MID AFTERNOON FOR
OROGRAPHICALLY INDUCED PRECIP. BY THIS AFTERNOON...LOW LVLS WILL
WARM ENOUGH...WITH SFC HIGHS E OF THE DIVIDE...APPROACHING OR JUST
CRESTING THE 70 DEG MARK IN THE BASINS AND EAST...TO CREATE SOME
INSTABILITY LATE THIS AFTERNOON AND EARLY EVENING. HOWEVER...EVEN
WITH BEST UPR FORCING FROM JET THIS AFTERNOON/EVENING...MEAGER
MOISTURE WILL SEVERELY LIMIT CONVECTIVE DEVELOPMENT FOR MOST AREAS.
THE BEST CHANCE FOR ISOLATED THUNDER E OF THE DIVIDE WILL ALL BE
ABOUT THE TIMING...AND WILL TAKE A FRONT...SOME BRIEF SHALLOW
MOISTURE POOLING NEAR NEAR THE FRONT...AND PROBABLY SOME NEARBY
TERRAIN TO LEND A HELPING HAND. ATTM...THE BEST LOCATION APPEARS TO
BE IN THE BIG HORN BASIN...WITH THE FAR SOUTHERN PORTION MOST
FAVORABLE...ALONG THE OWL CREEK AND BRIDGER MOUNTAINS...NORTH TO
PERHAPS THERMOPOLIS AND/OR WORLAND. MOSTLY DRY ADIABATIC ATMOSPHERE
SOUTH AND EAST OF THE THE BIG HORN BASIN WILL ONLY BE SLIGHTLY
UNSTABLE EVEN WITH RELATIVELY HIGH LAPSE RATES...AND THE WINDOW
SHORT FOR CONVECTION TO GET THRU. DIFFICULT TO ASCERTAIN WHERE THE
NAM IS/WAS GETTING THE RELATIVELY HIGH BL MOISTURE IN A SW FLOW
REGIME FOR NATRONA COUNTY...GENERATING RATHER LARGE CAPE. IT HAS
TONED DOWN SOME IN TONIGHTS RUN...BUT STILL SHOWS IT TO SOME
DEGREE...ALBEIT UNDER FAIRLY WELL CAPPED SKIES. OVERALL...JUST
DOESN`T LOOK ALL THAT PROMISING. STILL HAVE LOW POPS FOR LATE
AFTERNOON/EVE JUST IN CASE...WITH VIRGA THE MOSTLY LIKELY MAIN EVENT
FOR MUCH OF THE AREA. 2 INCHES OF WET SNOW AT BEST IN ISOLATED
LOCATIONS IN THE WRN MOUNTAINS...WITH MOST LOCATIONS GETTING HALF
THAT WITH SEASONALLY WARM CONDITIONS. OTHERWISE...THE SFC TO MID LVL
P AND T PATTERN WILL FAVOR INCREASED WINDS THRU THE DAY. HOWEVER IT
STILL APPEARS THAT ONLY VERY ISOLATED HIGH WIND CONDITIONS WILL
MANIFEST...IF AT ALL. JUST NOT ENOUGH CONFIDENCE TO WARN FOR THIS.

SATURDAY WILL BE SOMEWHAT COOLER N OF THE FRONT...BUT NOTHING
TOO DRASTIC WITH HIGH TEMPS STILL REACHING INTO THE MIDDLE 60S FOR
MANY LOW ELEVATION LOCALS...AND ALL WITH LESS WIND THAN FRIDAY. AS A
WEAK PRESSURE GRAD FILLS IN. STALLED FRONT NEAR AND JUST NORTH OF
THE WY/CO BORDER WILL ALLOW FOR SOME CONTINUED CONVECTIVE
DEVELOPMENT...ESPECIALLY BY MID DAY...AND MAY PUSH UP TO THE VERY
SRN REACHES OF NATRONA COUNTY. SUNDAY AFTERNOON WILL OFFER THE NEXT
BEST CHANCE FOR ISOLATED TO WIDELY SCATTERED SHOWERS WITH SOME
THUNDER AS LOW LEVELS WARM (NEAR 70S AGAIN) AND A WEAK UPR
DISTURBANCE MOVES THROUGH WHILE A WEAK CLIPPER TYPE FRONT BRUSHES
OUR ERN ZONES. GENERALLY 30 PERCENT OF LESS POPS FOR THIS
PERIOD.

.LONG TERM...MONDAY THROUGH FRIDAY

OUR MAIN WEATHER MAKER DURING THIS PERIOD WILL BE AN UPPER LOW
WOBBLING ITS WAY EASTWARD ALONG THE ALEUTIAN ISLANDS EARLY THIS
MORNING.  THIS SYSTEM WILL TAKE THE FORM OF AN UPRIGHT TROUGH ALONG
130W BY 00Z TUESDAY...PUMPING UP A RIDGE ACROSS THE ROCKIES.  THIS
WILL BRING DRY AND MILD CONDITIONS ON MONDAY.

TROUGH BECOMES MORE NEGATIVELY TILTED AS IT PUSHES INTO THE
INTERMOUNTAIN WEST ON TUESDAY AND THEN THE FUN BEGINS.  18/00Z ECMWF
IS MUCH MORE PROGRESSIVE THAN EARLIER RUNS...SWINGING THE UPPER
TROUGH ACROSS THE ROCKIES ON WEDNESDAY AND INTO THE PLAINS WEDNESDAY
NIGHT...SHORTWAVE RIDGE BUILDING IN THURSDAY MORNING.  THOUGH
GFS/GEFS MEAN HAVE ALSO TRENDED MORE PROGRESSIVE...THE DETERMINISTIC
CONTINUES BRIEFLY STALL OUT A CLOSED UPPER LOW OVER MONTANA ON
WEDNESDAY BEFORE PUSHING THE WHOLE MESSY TROUGH OUT INTO THE PLAINS
THURSDAY NIGHT.  THESE DIFFERENCES ALSO TRANSLATE INTO SUBSTANTIAL
SPREAD UPSTREAM WITH ECMWF BRINGING NEXT PACIFIC SYSTEM ONSHORE ON
FRIDAY WHILE GFS KEEPS THE SYSTEM OFF THE COAST.   ECMWF
DETERMINISTIC IS IN OVERALL AGREEMENT WITH THE EC EM...THE GFS IS ON
THE SLOW END OF ITS ENSEMBLE MEMBERS.

GIVEN THE ONGOING RUN-TO-RUN INCONSISTENCIES...THE FORECAST GIVES
THE MOST WEIGHT TO CONTINUITY.

ON TUESDAY...VERY MILD AND WINDY CONDITIONS WILL DEVELOP ACROSS
CENTRAL AREAS AS PACIFIC COLD FRONT PUSHES ACROSS IDAHO WITH
INCREASING CHANCES OF SHOWERS AND THUNDERSTORMS ACROSS THE
WEST...ISOLATED STORMS SPREADING EAST LATE IN THE DAY.  SNOW LEVELS
WILL REMAIN QUITE HIGH TUESDAY AHEAD OF THE FRONT...GENERALLY AROUND
10KFT AND UP.   RAPID SNOW MELT AND SIGNIFICANT RISES IN CREEKS AND
STREAMS WILL BE A CONCERN WITH THE WARM TEMPERATURES...ESPECIALLY
WITH THE POTENTIAL FOR RAIN NEAR AND BELOW 10KFT.

ON TUESDAY NIGHT AND WEDNESDAY...COLD FRONT WILL PUSH ACROSS THE
AREA SPREADING SHOWERS AND ISOLATED THUNDERSTORMS EAST OF THE DIVIDE
WITH SNOW LEVELS LOWERING TO THE VALLEY FLOORS IN THE WEST.
PRECIPITATION LOOKS TO BE MAINLY RAIN OR A RAIN/SNOW MIX ACROSS THE
CENTRAL BASINS THROUGH THE DAY.

THURSDAY AND FRIDAY...FORECAST MAINTAINS CHANCES OF MOUNTAIN SNOW
SHOWERS WITH SLIGHT CHANCES OF RAIN/SNOW SHOWERS IN THE VALLEYS AND
BASINS DURING THIS PERIOD WITH UNCERTAINTY ON HOW FAST THIS TROUGH
WILL EXIT AND THE NEXT ONE ARRIVES.

&&

.AVIATION.../12Z ISSUANCE/

A STORM SYSTEM PASSING NORTH OF THE COWBOY STATE WILL RESULT IN
SCATTERED TO LOCALLY NUMEROUS MOUNTAIN SNOW/VALLEY RAIN
SHOWERS...MAINLY ALONG AND NORTHWEST OF A KAFO...KPNA...KDUB...KCOD
LINE TODAY. THE BEST CHANCE OF CONVECTION IN THIS AREA WILL BE THIS
MORNING...WITH THE PRECIPITATION SHIFTING EAST AND SOUTH WITH
TIME...BUT BECOMING LESS WIDESPREAD DURING THE AFTERNOON. KJAC WILL
LIKELY SEE MVFR CONDITIONS IN RAIN SHOWERS THIS MORNING...POSSIBLY
LINGERING INTO THE AFTERNOON. EAST OF THE DIVIDE...AS WELL AS
SWEETWATER COUNTY...THE MAIN CONCERN WILL BE THE VERY WINDY WESTERLY
WINDS IN THE KRKS-KCPR WIND CORRIDOR AS WELL AS LEE SIDE OF
MOUNTAINS AND ADJACENT FOOTHILLS. SOME LOW LEVEL WIND SHEAR IS
EXPECTED AT KCOD AND KLND THIS MORNING...BEFORE STRONGER WINDS MIX
TO THE SURFACE BY MIDDAY. DOWNSLOPING AND A VERY DRY ATMOSPHERE EAST
OF THE DIVIDE WILL INHIBIT MOST IF NOT ALL CONVECTION...WITH THE
BEST SHOT AT CONVECTION ACROSS NORTHERN WYOMING. CANNOT RULE OUT
SOME THUNDER...BUT TIMING OF CONVECTION OUT WEST...AND DRY
CONDITIONS EAST SHOULD KEEP LIGHTNING ISOLATED AT BEST. A PACIFIC
COLD FRONT WILL PUSH ACROSS THE AREA LATER THIS AFTERNOON AND
EVENING...WITH A SLIGHT WIND SHIFT IN MOST CASES...WITH BREEZY WINDS
CONTINUING...BUT MORE IMPORTANTLY IMPROVING CONDITIONS WITH
CONVECTION WANING QUICKLY BETWEEN 00Z AND 03Z SATURDAY. ALSO WINDS
WILL BEGIN TO WEAKEN BY LATE EVENING. NORTHWEST/WESTERN MOUNTAINS
WILL BE OBSCURED MUCH OF THE TIME THROUGH EARLY AFTERNOON...WITH
IMPROVING CONDITIONS BY LATE AFTERNOON/EARLY EVENING.

&&

.FIRE WEATHER...

TODAY...THE BASIN ZONES WILL CLIMB NEAR OR INTO THE LOWER 70S...AHEAD OF
THE NEXT SPRING WEATHER SYSTEM DUE TO PUSH THROUGH THE FORECAST AREA
THROUGH THE DAY. MOUNTAIN INDUCED RAIN/SNOW CHANCES WILL INCREASE
THROUGH THE MORNING AND AFTERNOON HOURS... LASTING INTO THE EARLY
EVENING. HOWEVER...NEW SNOWFALL ACCUMULATIONS LOOK TO REMAIN ON THE
LOW SIDE WITH AN INCH OR TWO OF WET SNOW AT BEST. WINDS WILL ALSO
PICK UP TO THE BREEZY CATEGORY ACROSS MOST OF THE FORECAST
ZONES...WITH THE USUAL WIND PRONE AREAS OF THE SOUTHERN DISPATCH
ZONES...MOUNTAIN RIDGE TOPS AND NORTHERN CODY FOOTHILLS POSSIBLY
GETTING SOME ISOLATED HIGH WINDS. IN ADDITION...BY THIS AFTERNOON
THERE WILL BE AN INCREASING CHANCES FOR GUSTY LIGHT SHOWERS AND
PERHAPS AN ISOLATED THUNDERSTORM LASTING INTO THE EVENING PERIOD.
SATURDAY...HIGH TEMPERATURES WILL BE SEASONAL...AND THE WINDS  MORE
TAME...WITH ISOLATED TO WIDELY SCATTERED CHANCES FOR SHOWERS OR AN
ISOLATED THUNDERSTORM SUNDAY AFTERNOON...MAINLY EAST OF THE
DIVIDE.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...WM
FIRE WEATHER...BRAUN










000
FXUS65 KRIW 180547
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1146 PM MDT THU APR 17 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY

QUIET WEATHER FOR WEST CENTRAL WYOMING THROUGH TONIGHT WITH WEAK
RIDGING ALOFT. ONLY EXPECT SOME MID TO HIGH LEVEL CLOUDINESS INTO
EARLY FRIDAY MORNING. WILL THEN WATCH NEXT SHORTWAVE TROUGH TO
APPROACH THE NORTHERN ROCKIES BY FRIDAY AFTERNOON. MOST OF THIS
ENERGY LOOKS TO STAY OVER MONTANA...BUT SYSTEM WILL DRAG A COLD
FRONT ACROSS WYOMING LATER FRIDAY. ADDITIONALLY...SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP MAINLY OVER THE
NORTHWEST MOUNTAINS...FROM THE TETON RANGE TO THE ABSAROKA RANGE.
LIKELY TO BE CONVECTIVE SNOW SHOWERS OVER THE HIGHEST MOUNTAIN
RANGES AND PARTS OF YELLOWSTONE NATIONAL PARK. TEMPERATURES WILL
BE WARM AND ABOVE NORMAL...JUST AHEAD OF THE COLD FRONT...EAST OF
THE CONTINENTAL DIVIDE ON FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY NIGHT

THE SHORTWAVE AND ASSOCIATED COLD FRONT WILL BE EXITING THE COWBOY
STATE RATHER QUICKLY FRIDAY EVENING...WITH CLEARING CONDITIONS BY
SATURDAY MORNING. THE WEEKEND WILL BE CALM AND SEASONAL WITH DRY
CONDITIONS EXPECTED AND LITTLE TO WIND. BY MONDAY...AN AMPLIFIED
RIDGE BUILDS OVER THE NORTHERN AND CENTRAL ROCKIES INTO CENTRAL
ALBERTA. AT THE SAME TIME...THE NORTH PACIFIC LOW THAT HAS BEEN NEAR
THE ALUETIAN CHAIN BEGINS TO DIG AND MOVE SOUTHEASTWARD TOWARD THE
PACIFIC NORTHWEST. THIS SYSTEM QUICKLY MAKES ITS WAY ONSHORE BY
TUESDAY MORNING...TRANSITIONING THE RIDGE EASTWARD AND TURNING THE
UPPER LEVEL FLOW TO THE SOUTHWEST. A WEAK SHORTWAVE AHEAD OF THE
SYSTEM WILL BRING WEAK RAIN AND SNOW SHOWERS ACROSS THE WESTERN
MOUNTAINS EARLY TUESDAY MORNING.

ON TUESDAY...SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS WILL
OCCUR ACROSS THE AREA AS THE COLD FRONT NEARS WESTERN PORTIONS OF
THE FORECAST AREA. AREAS EAST OF THE DIVIDE WILL BE IN THE WARM
SECTOR THROUGH LATE AFTERNOON...THUS GUSTY SOUTHWEST WINDS WILL
OCCUR FROM SWEETWATER TO SOUTHERN JOHNSON COUNTY. THIS WILL ALSO
KEEP SNOW LEVELS AT OR ABOVE 10KFT AHEAD OF THE COLD FRONT. THIS
WILL ALSO ACCELERATE SNOWMELT IN THE CENTRAL MOUNTAINS...WHICH MAY
CAUSE SIGNIFICANT RISES IN CREEKS AND STREAMS. ALTHOUGH THUNDERSTORM
ACTIVITY WILL BE MOSTLY ISOLATED...STRONG GUSTY WINDS WILL BE THE
MAIN HAZARD AS THE COLD FRONT MOVES THROUGH BY TUESDAY EVENING.

THE MAIN AREA OF LOW PRESSURE WILL MOVE INTO EAST-CENTRAL MONTANA BY
WEDNESDAY...TURNING THE UPPER LEVEL FLOW IN A MORE CYCLONIC
WEST-NORTHWEST FLOW. THIS...IN ADDITION TO H7 TEMPS OF -6 TO -9 WILL
BRING MORE WIDESPREAD SNOW ACROSS THE WEST. SNOW WILL ALSO REACH THE
VALLEY FLOOR TUESDAY NIGHT INTO WEDNESDAY MORNING. A DRY SLOT IS
EXPECTED BEHIND THE COLD FRONT DURING THIS TIME...IMPACTING AREAS
EAST OF THE DIVIDE. THIS WILL RESULT IN DOWNSLOPING...DRY
CONDITIONS. THIS WILL BE SHORT-LIVED...AS THE AFOREMENTIONED
CYCLONIC FLOW SPREADS ACROSS THE STATE. THIS WILL ALLOW FOR SHOWERS
AND ISOLATED THUNDERSTORMS TO ONCE AGAIN FORM DURING THE DAY
WEDNESDAY. SNOW WILL BE CONFINED TO THE HIGHER ELEVATIONS...WITH ANY
RAIN SHOWERS IN THE LOWER ELEVATIONS CHANGING OVER TO SNOW WEDNESDAY
NIGHT. SNOW ACCUMULATIONS WILL BE HEAVIEST IN THE MOUNTAINS DUE TO
FAVORED UPSLOPE CONDITIONS.

&&

.AVIATION.../06Z ISSUANCE/

A STORM SYSTEM PASSING NORTH OF THE COWBOY STATE WILL RESULT IN
SCATTERED TO LOCALLY NUMEROUS MOUNTAIN SNOW/VALLEY RAIN
SHOWERS...MAINLY ALONG AND NORTHWEST OF A KAFO...KPNA...KDUB...KCOD
LINE FRIDAY. THE BEST CHANCE OF CONVECTION IN THIS AREA WILL BE FROM
ABOUT 13Z TO 19Z...WITH THE PRECIPITATION SHIFTING EAST AND
SOUTH WITH TIME...BUT BECOMING LESS WIDESPREAD DURING THE AFTERNOON.
KJAC WILL LIKELY SEE MVFR CONDITIONS IN RAIN SHOWERS FRIDAY
MORNING...POSSIBLY LINGERING INTO THE AFTERNOON. EAST OF THE
DIVIDE...AS WELL AS SWEETWATER COUNTY...THE MAIN CONCERN WILL BE THE
VERY WINDY WESTERLY WINDS IN THE KRKS-KCPR WIND CORRIDOR AS WELL AS
LEE SIDE OF MOUNTAINS AND ADJACENT FOOTHILLS. SOME LOW LEVEL WIND
SHEAR IS EXPECTED AT KCOD AND KLND FRIDAY MORNING...BEFORE STRONGER
WINDS MIX TO THE SURFACE BY MIDDAY. DOWNSLOPING AND A VERY DRY
ATMOSPHERE EAST OF THE DIVIDE WILL INHIBIT MOST IF NOT ALL
CONVECTION...WITH THE BEST SHOT AT CONVECTION ACROSS NORTHERN
WYOMING. CANNOT RULE OUT SOME THUNDER...BUT TIMING OF CONVECTION OUT
WEST...AND DRY CONDITIONS EAST SHOULD KEEP LIGHTNING ISOLATED AT
BEST. A PACIFIC COLD FRONT WILL PUSH ACROSS THE AREA LATER
FRIDAY AFTERNOON AND EVENING...WITH A SLIGHT WIND SHIFT IN MOST
CASES...WITH BREEZY WINDS CONTINUING...BUT MORE IMPORTANTLY
IMPROVING CONDITIONS WITH CONVECTION WANING QUICKLY BETWEEN 00Z AND
03Z SATURDAY. ALSO WINDS WILL BEGIN TO WEAKEN BY LATE EVENING.
NORTHWEST/WESTERN MOUNTAINS WILL BE OBSCURED MUCH OF THE TIME
THROUGH EARLY FRIDAY AFTERNOON...WITH IMPROVING CONDITIONS BY LATE
AFTERNOON/EARLY EVENING.

&&

.FIRE WEATHER...

LOW PRESSURE WILL MOVE OVER MONTANA FRIDAY AFTERNOON AND EVENING.
THIS WILL BRING A FRONTAL BOUNDARY ACROSS NORTHERN AND CENTRAL
WYOMING. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
OVER NORTHWEST WYOMING...INCLUDING THE TETONS AND YELLOWSTONE
NATIONAL PARK. GUSTY WINDS WILL BE COMMON MOST AREAS FRIDAY
AFTERNOON AND EVENING. WIND DIRECTION WILL GENERALLY BE FROM THE
WEST...RESULTING IN VERY GOOD SMOKE DISPERSAL. OTHERWISE...THERE
WILL BE A QUIET WEATHER PATTERN SHAPING UP THIS WEEKEND ACROSS WEST
CENTRAL WYOMING WITH VERY LITTLE OR NO PRECIPITATION AND LESS WIND.

&&

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

&&

$$

SHORT TERM...KPL
LONG TERM...LAVOIE
AVIATION...WM
FIRE WEATHER...KPL









000
FXUS65 KRIW 172032
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
232 PM MDT THU APR 17 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY

QUIET WEATHER FOR WEST CENTRAL WYOMING THROUGH TONIGHT WITH WEAK
RIDGING ALOFT. ONLY EXPECT SOME MID TO HIGH LEVEL CLOUDINESS INTO
EARLY FRIDAY MORNING. WILL THEN WATCH NEXT SHORTWAVE TROUGH TO
APPROACH THE NORTHERN ROCKIES BY FRIDAY AFTERNOON. MOST OF THIS
ENERGY LOOKS TO STAY OVER MONTANA...BUT SYSTEM WILL DRAG A COLD
FRONT ACROSS WYOMING LATER FRIDAY. ADDITIONALLY...SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO DEVELOP MAINLY OVER THE
NORTHWEST MOUNTAINS...FROM THE TETON RANGE TO THE ABSAROKA RANGE.
LIKELY TO BE CONVECTIVE SNOW SHOWERS OVER THE HIGHEST MOUNTAIN
RANGES AND PARTS OF YELLOWSTONE NATIONAL PARK. TEMPERATURES WILL
BE WARM AND ABOVE NORMAL...JUST AHEAD OF THE COLD FRONT...EAST OF
THE CONTINENTAL DIVIDE ON FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY NIGHT

THE SHORTWAVE AND ASSOCIATED COLD FRONT WILL BE EXITING THE COWBOY
STATE RATHER QUICKLY FRIDAY EVENING...WITH CLEARING CONDITIONS BY
SATURDAY MORNING. THE WEEKEND WILL BE CALM AND SEASONAL WITH DRY
CONDITIONS EXPECTED AND LITTLE TO WIND. BY MONDAY...AN AMPLIFIED
RIDGE BUILDS OVER THE NORTHERN AND CENTRAL ROCKIES INTO CENTRAL
ALBERTA. AT THE SAME TIME...THE NORTH PACIFIC LOW THAT HAS BEEN NEAR
THE ALUETIAN CHAIN BEGINS TO DIG AND MOVE SOUTHEASTWARD TOWARD THE
PACIFIC NORTHWEST. THIS SYSTEM QUICKLY MAKES ITS WAY ONSHORE BY
TUESDAY MORNING...TRANSITIONING THE RIDGE EASTWARD AND TURNING THE
UPPER LEVEL FLOW TO THE SOUTHWEST. A WEAK SHORTWAVE AHEAD OF THE
SYSTEM WILL BRING WEAK RAIN AND SNOW SHOWERS ACROSS THE WESTERN
MOUNTAINS EARLY TUESDAY MORNING.

ON TUESDAY...SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS WILL
OCCUR ACROSS THE AREA AS THE COLD FRONT NEARS WESTERN PORTIONS OF
THE FORECAST AREA. AREAS EAST OF THE DIVIDE WILL BE IN THE WARM
SECTOR THROUGH LATE AFTERNOON...THUS GUSTY SOUTHWEST WINDS WILL
OCCUR FROM SWEETWATER TO SOUTHERN JOHNSON COUNTY. THIS WILL ALSO
KEEP SNOW LEVELS AT OR ABOVE 10KFT AHEAD OF THE COLD FRONT. THIS
WILL ALSO ACCELERATE SNOWMELT IN THE CENTRAL MOUNTAINS...WHICH MAY
CAUSE SIGNIFICANT RISES IN CREEKS AND STREAMS. ALTOUGH THUNDERSTORM
ACTIVITY WILL BE MOSTLY ISOLATED...STRONG GUSTY WINDS WILL BE THE
MAIN HAZARD AS THE COLD FRONT MOVES THROUGH BY TUESDAY EVENING.

THE MAIN AREA OF LOW PRESSURE WILL MOVE INTO EAST-CENTRAL MONTANA BY
WEDNESDAY...TURNING THE UPPER LEVEL FLOW IN A MORE CYCLONIC
WEST-NORTHWEST FLOW. THIS...IN ADDITION TO H7 TEMPS OF -6 TO -9 WILL
BRING MORE WIDESPREAD SNOW ACROSS THE WEST. SNOW WILL ALSO REACH THE
VALLEY FLOOR TUESDAY NIGHT INTO WEDNESDAY MORNING. A DRY SLOT IS
EXPECTED BEHIND THE COLD FRONT DURING THIS TIME...IMPACTING AREAS
EAST OF THE DIVIDE. THIS WILL RESULT IN DOWNSLOPING...DRY
CONDITIONS. THIS WILL BE SHORT-LIVED...AS THE AFOREMENTIONED
CYCLONIC FLOW SPREADS ACROSS THE STATE. THIS WILL ALLOW FOR SHOWERS
AND ISOLATED THUNDERSTORMS TO ONCE AGAIN FORM DURING THE DAY
WEDNESDAY. SNOW WILL BE CONFINED TO THE HIGHER ELEVATIONS...WITH ANY
RAIN SHOWERS IN THE LOWER ELEVATIONS CHANGING OVER TO SNOW WEDNESDAY
NIGHT. SNOW ACCUMULATIONS WILL BE HEAVIEST IN THE MOUNTAINS DUE TO
FAVORED UPSLOPE CONDITIONS.

&&

.AVIATION.../00Z ISSUANCE/

MID TO UPPER LEVEL MOISTURE MOVES INTO WEST CENTRAL WYOMING TONIGHT
AHEAD OF A SHORTWAVE TROUGH. VFR CONDITIONS PREVAIL TONIGHT AND
MUCH OF FRIDAY. EXCEPTION LOOKS TO BE NORTHWEST WYOMING BY FRIDAY
MORNING. CONVECTIVE CLOUDS WILL DEVELOP...WHICH COULD LEAD TO ONE
OR TWO THUNDERSTORMS. ANY SHOWERS OR THUNDERSTORMS COULD PRODUCE
GUSTY WIND. IN ADDITION...SCATTERED PRECIPITATION WILL AFFECT
KJAC AIRPORT UNTIL EARLY EVENING...OR ABOUT 02Z. AN ISOLATED
THUNDERSTORM COULD ALSO BE IN THE KCOD VICINITY DURING THIS TIME.

OTHERWISE...THIS ACTIVITY WILL BE SHORT LIVED AS DRIER AIR MOVES
INTO THE REGION FRIDAY NIGHT. IT WILL BE DRY...LESS WIND AND A
LITTLE WARMER ON SATURDAY.

&&

.FIRE WEATHER...

LOW PRESSURE WILL MOVE OVER MONTANA FRIDAY AFTERNOON AND EVENING.
THIS WILL BRING A FRONTAL BOUNDARY ACROSS NORTHERN AND CENTRAL
WYOMING. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
OVER NORTHWEST WYOMING...INCLUDING THE TETONS AND YELLOWSTONE
NATIONAL PARK. GUSTY WINDS WILL BE COMMON MOST AREAS FRIDAY
AFTERNOON AND EVENING. WIND DIRECTION WILL GENERALLY BE FROM THE
WEST...RESULTING IN VERY GOOD SMOKE DISPERSAL. OTHERWISE...THERE
WILL BE A QUIET WEATHER PATTERN SHAPING UP THIS WEEKEND ACROSS WEST
CENTRAL WYOMING WITH VERY LITTLE OR NO PRECIPITATION AND LESS WIND.

&&

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

$$

SHORT TERM...KPL
LONG TERM...LAVOIE
AVIATION...KPL
FIRE WEATHER...KPL






000
FXUS65 KRIW 171745
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1145 AM MDT THU APR 17 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

SAT IMAGERY W OF THE MISSISSIPPI SHOWS UPR LVL TROF FROM THE UPR
MISS VALLEY...SOUTH THEN SW INTO THE SRN ROCKIES. RIDGE TO THE WEST
OVR THE COASTAL STATES HAS WY STUCK BETWEEN THE TWO AND UNDER NW
FLOW. N/S ORIENTED JET QUICKLY SWINGING ACROSS WY...PUSHING THE LAST
UPR VORT MAX OUT TO THE EAST WITH IT...AND TAKING THE LAST OF THE
INSTABILITY AND SHOWERS WITH IT. FURTHER UPSTREAM AT 140 W IS THE
NEXT TROF AND JET THAT WILL AFFECT OUR REGION LATER FRIDAY. AT THE
SFC...THE LOW AND FRONT THAT PUSHED THRU THE STATE TUE IS NOW WELL
OFF TO THE E IN IA. WEAK HIGH P IS GENERALLY DRAPED ACROSS THE STATE
WITH A WEAK N/S INVERTED TROF SPLITTING THE STATE IN TWO.

TODAY...PATCHY FOG POSSIBLE ERN ZONES THIS MORNING UNDER MOIST L
LVLS WEAK FLOW AND BUILDING HIGH PRESS...WITH NATRONA COUNTY LOOKING TO
HAVE THE BEST CHC. OTHERWISE...WEAK SFC PATTERN WITH UPR LVLS
TRANSITIONING TO RIDGING AND DRYING. WITH H7 TEMPS WARMING SOME 3 TO
4 DEG...WARMING AT THE SFC ALSO BEGINS  TODAY...REACHING NEAR OR
INTO THE LOWER 60S ACROSS THE LOWER ELEVATIONS. WINDS WILL ALSO
REMAIN TAME FOR THE MOST PART TODAY.

FRIDAY...WARMING CONTINUES WITH 70S WITHIN REACH AS THE RIDGE MOVES
THRU OVERHEAD. LEE TROFING BUILDS ACROSS THE ERN COUNTIES UNDER LL
SW FLOW AND AHEAD OF THE NEXT UPR TROF. AT THE SAME TIME...THE UPR
TROF AND JET WILL SPARK RAPID CYCLOGENESIS OVR THE PAC NW...MOVING
EWD QUICKLY DURING THE DAY WITHIN THE VERY PROGRESSIVE UPR LVL
PATTERN. LEE CYCLOGENESIS WILL ALSO BEGIN BY FRIDAY AFTERNOON OVR
THE ERN PORTION OF THE STATE ALONG THE LEE TROF...WHILE WEAK GREAT
BASIN LOW P WILL MERGE WITH THE DEVELOPING NW LOW. WITH THIS SPLIT
SYSTEM TAKING SHAPE...IT APPEARS THAT WE WILL NOT BE ABLE TO TAP
INTO MUCH IN THE WAY OF DEEP MOISTURE...AS MOST WILL EITHER HEAD OFF
TO THE NORTH WITH THE ONE CYCLONE...OR GET SHUNTED S AND E WITH THE
OTHER. MID LVL MOISTURE WILL WORK ITS WAY INTO THE WRN ZONES...BUT
THE WRN MOUNTAINS WILL WRING MOST OF WHAT IS AVAILABLE OUT...LEAVING
LITTLE FOR THE LOWER ELEVATIONS TO WORK WITH. IN ADDITION TO UPR
LVL FORCING...FRONTOGENESIS WILL ALSO COMMENCE TO OUR NORTH
NORTHWEST...KICKING THRU THE FA FROM THE AFTERNOON THRU EARLY
EVENING PERIOD...GIVING THE AREA EAST OF THE DIVIDE THEIR BEST BUT
MODEST SHOT AT ANY PRECIP...MUCH IN THE FORM OF VIRGA.
OTHERWISE...THE SFC TO MID LVL P AND T PATTERN WILL BEGIN TO FAVOR
INCREASED WINDS THRU THE DAY ON FRIDAY. ATTM...IT APPEARS THAT ONLY
ISOLATED HIGH WIND CONDITIONS WILL MANIFEST...BUT IT IS WORTH
MONITORING ACROSS THE USUAL WIND PRONE ZONES FOR EXPANSION AS THIS
COMPLEX BUT MOSTLY DRY SYSTEM EVOLVES. SATURDAY WILL BE SOMEWHAT
COOLER OVERALL...BUT NOTHING TOO DRASTIC WITH HIGH TEMPS STILL REACH
INTO THE 60S FOR MANY LOCATIONS...AND ALL WITH LESS WIND THAN
FRIDAY.

.LONG TERM...SUNDAY THROUGH THURSDAY

THE MAIN WEATHER MAKER DURING THIS PERIOD WILL BE UPPER LOW
CURRENTLY SLOWLY WOBBLING ITS WAY EASTWARD ALONG THE ALEUTIAN
CHAIN.

BEFOREHAND...A SHORTWAVE WILL RACE EAST ALONG THE MONTANA/CANADIAN
BORDER ON SUNDAY AND DRIVE A WEAK/DRY COLD FRONT INTO NORTHERN
WYOMING.  SOME LINGERING MOISTURE AND SLIGHT INSTABILITY ACROSS THE
SOUTH WILL RESULT IN SLIGHT CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS MAINLY ALONG AND SOUTH OF INTERSTATE 80.

GFS HAS TRENDED TOWARD ECMWF EARLIER SOLUTIONS OF A MORE
DISORGANIZED SYSTEM COMING ONSHORE.  THE ALEUTIAN LOW WOBBLES ITS
WAY TO NEAR THE NW COAST BY 12Z TUESDAY WITH LEAD SHORTWAVE SWINGING
ONTO THE CA COAST...ACROSS NW WYOMING LATE TUESDAY...THEN CLOSING
OFF AND BECOMING QUASI-STATIONARY NEAR HAVRE ON WEDNESDAY.
MEANWHILE...ALEUTIAN LOW SHEARS SE INT THE FOUR CORNERS REGION
BEFORE LIFTING INTO THE PLAINS.  THE ECMWF IS MUCH QUICKER IN DOING
SO THAN THE GFS...BUT THE GFS IS TRENDING FASTER OVER THE LAST FEW
RUNS.

OVERALL...FORECAST REMAINS ON TRACK WITH SURFACE LOW EXPECTED TO
DEEPEN IN THE VICINITY OF BILLINGS ON TUESDAY WITH COLD FRONT
PUSHING INTO THE WEST TUESDAY...CENTRAL AND EASTERN WYOMING IN THE
WARM SECTOR.  THIS TRANSLATES INTO INCREASING SHOWERS AND SOME
THUNDERSTORMS IN THE WEST WITH SNOW LEVELS INITIALLY QUITE HIGH ON
TUESDAY...AT OR ABOVE 10KFT...WHILE WINDY AND VERY WARM CONDITIONS
PREVAIL EAST OF THE DIVIDE.  THIS PATTERN WILL BE FAVORABLE FOR
ACCELERATED SNOWMELT IN THE CENTRAL MOUNTAINS ALONG WITH POSSIBLE
SIGNIFICANT RISES IN CREEKS AND STREAMS...ESPECIALLY IN THE BIGHORN
MOUNTAINS AND DOWNSTREAM RIVER BASINS.

PACIFIC COLD FRONT WILL PUSH ACROSS CENTRAL WYOMING TUESDAY
NIGHT...BUT DOWNSLOPE WESTERLY WINDS ARE EXPECTED TO KEEP SHOWER AND
THUNDERSTORM ACTIVITY MOSTLY ISOLATED WITH THE MAIN HAZARD OF STRONG
WIND GUSTS WITH THE FRONTAL PASSAGE.  IN THE WEST...SNOW LEVELS ARE
EXPECTED TO LOWER TO VALLEY FLOORS TUESDAY NIGHT WITH CYCLONIC
WESTERLY FLOW BRINGING MORE WIDESPREAD SNOW...ESPECIALLY TO YNP AND
THE TETON RANGE...INTO WEDNESDAY.   NORTH AND CENTRAL AREAS WILL
HAVE BETTER CHANCES OF RAIN AND SNOW SHOWERS LATE WEDNESDAY INTO
THURSDAY IN NW FLOW WITH H5 COLD POOL ALOFT.

&&

.AVIATION.../18Z ISSUANCE/

SHORT TERM FOR WEST CENTRAL WYOMING IS FOR VFR CONDITIONS AND
UNLIMITED VISIBILITIES. SOME HIGH CLOUDS WILL MOVE IN ALOFT...SO
WILL CALL FOR PARTY CLOUDY SKY BY TONIGHT. ONLY TERMINAL TO WATCH
NEXT 24-36 HOURS WILL BE KJAC FOR INCREASING PRECIPITATION CHANCES
WITH WEAK SYSTEM MOVING INTO NORTHWEST WYOMING BY FRIDAY AFTERNOON.
AT THIS TIME...LOOKS LIKE PRECIPITATION TYPE WILL BE RAIN AT KJAC.

&&

.FIRE WEATHER...

A WEAK SURFACE PATTERN TODAY WILL KEEP WINDS IN CHECK FOR ANOTHER
DAY AS HIGH TEMPERATURES WARM INTO THE 60S ACROSS MANY LOWER
ELEVATIONS. FRIDAY...THE BASINS WILL CLIMB NEAR OR INTO THE LOWER
70S...AHEAD OF THE NEXT SPRING WEATHER SYSTEM DUE TO PUSH THROUGH
THE FORECAST AREA THROUGH THE DAY. WINDS WILL ALSO PICK UP TO THE
BREEZY CATEGORY ACROSS MOST OF THE FORECAST ZONES...WITH THE USUAL
WIND PRONE AREAS OF THE SOUTHERN DISPATCH ZONES...MOUNTAIN RIDGE
TOPS AND NORTHERN CODY FOOTHILLS POSSIBLY GETTING SOME ISOLATED HIGH
WINDS. IN ADDITION...BY FRIDAY AFTERNOON THERE WILL BE AN INCREASING
CHANCE FOR SHOWER AND ISOLATED THUNDER LASTING INTO THE EVENING
PERIOD. SATURDAY...HIGH TEMPERATURES WILL BE SOMEWHAT COOLER...BUT
WINDS WILL ALSO BE MORE TAME.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...WM
AVIATION...KPL
FIRE WEATHER...BRAUN






000
FXUS65 KRIW 170934
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
334 AM MDT THU APR 17 2014

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT

SAT IMAGERY W OF THE MISSISSIPPI SHOWS UPR LVL TROF FROM THE UPR
MISS VALLEY...SOUTH THEN SW INTO THE SRN ROCKIES. RIDGE TO THE WEST
OVR THE COASTAL STATES HAS WY STUCK BETWEEN THE TWO AND UNDER NW
FLOW. N/S ORIENTED JET QUICKLY SWINGING ACROSS WY...PUSHING THE LAST
UPR VORT MAX OUT TO THE EAST WITH IT...AND TAKING THE LAST OF THE
INSTABILITY AND SHOWERS WITH IT. FURTHER UPSTREAM AT 140 W IS THE
NEXT TROF AND JET THAT WILL AFFECT OUR REGION LATER FRIDAY. AT THE
SFC...THE LOW AND FRONT THAT PUSHED THRU THE STATE TUE IS NOW WELL
OFF TO THE E IN IA. WEAK HIGH P IS GENERALLY DRAPED ACROSS THE STATE
WITH A WEAK N/S INVERTED TROF SPLITTING THE STATE IN TWO.

TODAY...PATCHY FOG POSSIBLE ERN ZONES THIS MORNING UNDER MOIST L
LVLS WEAK FLOW AND BUILDING HIGH PRESS...WITH NATRONA COUNTY LOOKING TO
HAVE THE BEST CHC. OTHERWISE...WEAK SFC PATTERN WITH UPR LVLS
TRANSITIONING TO RIDGING AND DRYING. WITH H7 TEMPS WARMING SOME 3 TO
4 DEG...WARMING AT THE SFC ALSO BEGINS  TODAY...REACHING NEAR OR
INTO THE LOWER 60S ACROSS THE LOWER ELEVATIONS. WINDS WILL ALSO
REMAIN TAME FOR THE MOST PART TODAY.

FRIDAY...WARMING CONTINUES WITH 70S WITHIN REACH AS THE RIDGE MOVES
THRU OVERHEAD. LEE TROFING BUILDS ACROSS THE ERN COUNTIES UNDER LL
SW FLOW AND AHEAD OF THE NEXT UPR TROF. AT THE SAME TIME...THE UPR
TROF AND JET WILL SPARK RAPID CYCLOGENESIS OVR THE PAC NW...MOVING
EWD QUICKLY DURING THE DAY WITHIN THE VERY PROGRESSIVE UPR LVL
PATTERN. LEE CYCLOGENESIS WILL ALSO BEGIN BY FRIDAY AFTERNOON OVR
THE ERN PORTION OF THE STATE ALONG THE LEE TROF...WHILE WEAK GREAT
BASIN LOW P WILL MERGE WITH THE DEVELOPING NW LOW. WITH THIS SPLIT
SYSTEM TAKING SHAPE...IT APPEARS THAT WE WILL NOT BE ABLE TO TAP
INTO MUCH IN THE WAY OF DEEP MOISTURE...AS MOST WILL EITHER HEAD OFF
TO THE NORTH WITH THE ONE CYCLONE...OR GET SHUNTED S AND E WITH THE
OTHER. MID LVL MOISTURE WILL WORK ITS WAY INTO THE WRN ZONES...BUT
THE WRN MOUNTAINS WILL WRING MOST OF WHAT IS AVAILABLE OUT...LEAVING
LITTLE FOR THE LOWER ELEVATIONS TO WORK WITH. IN ADDITION TO UPR
LVL FORCING...FRONTOGENESIS WILL ALSO COMMENCE TO OUR NORTH
NORTHWEST...KICKING THRU THE FA FROM THE AFTERNOON THRU EARLY
EVENING PERIOD...GIVING THE AREA EAST OF THE DIVIDE THEIR BEST BUT
MODEST SHOT AT ANY PRECIP...MUCH IN THE FORM OF VIRGA.
OTHERWISE...THE SFC TO MID LVL P AND T PATTERN WILL BEGIN TO FAVOR
INCREASED WINDS THRU THE DAY ON FRIDAY. ATTM...IT APPEARS THAT ONLY
ISOLATED HIGH WIND CONDITIONS WILL MANIFEST...BUT IT IS WORTH
MONITORING ACROSS THE USUAL WIND PRONE ZONES FOR EXPANSION AS THIS
COMPLEX BUT MOSTLY DRY SYSTEM EVOLVES. SATURDAY WILL BE SOMEWHAT
COOLER OVERALL...BUT NOTHING TOO DRASTIC WITH HIGH TEMPS STILL REACH
INTO THE 60S FOR MANY LOCATIONS...AND ALL WITH LESS WIND THAN
FRIDAY.

.LONG TERM...SUNDAY THROUGH THURSDAY
THE MAIN WEATHER MAKER DURING THIS PERIOD WILL BE UPPER LOW
CURRENTLY SLOWLY WOBBLING ITS WAY EASTWARD ALONG THE ALEUTIAN
CHAIN.

BEFOREHAND...A SHORTWAVE WILL RACE EAST ALONG THE MONTANA/CANADIAN
BORDER ON SUNDAY AND DRIVE A WEAK/DRY COLD FRONT INTO NORTHERN
WYOMING.  SOME LINGERING MOISTURE AND SLIGHT INSTABILITY ACROSS THE
SOUTH WILL RESULT IN SLIGHT CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS MAINLY ALONG AND SOUTH OF INTERSTATE 80.

GFS HAS TRENDED TOWARD ECMWF EARLIER SOLUTIONS OF A MORE
DISORGANIZED SYSTEM COMING ONSHORE.  THE ALEUTIAN LOW WOBBLES ITS
WAY TO NEAR THE NW COAST BY 12Z TUESDAY WITH LEAD SHORTWAVE SWINGING
ONTO THE CA COAST...ACROSS NW WYOMING LATE TUESDAY...THEN CLOSING
OFF AND BECOMING QUASI-STATIONARY NEAR HAVRE ON WEDNESDAY.
MEANWHILE...ALEUTIAN LOW SHEARS SE INT THE FOUR CORNERS REGION
BEFORE LIFTING INTO THE PLAINS.  THE ECMWF IS MUCH QUICKER IN DOING
SO THAN THE GFS...BUT THE GFS IS TRENDING FASTER OVER THE LAST FEW
RUNS.

OVERALL...FORECAST REMAINS ON TRACK WITH SURFACE LOW EXPECTED TO
DEEPEN IN THE VICINITY OF BILLINGS ON TUESDAY WITH COLD FRONT
PUSHING INTO THE WEST TUESDAY...CENTRAL AND EASTERN WYOMING IN THE
WARM SECTOR.  THIS TRANSLATES INTO INCREASING SHOWERS AND SOME
THUNDERSTORMS IN THE WEST WITH SNOW LEVELS INITIALLY QUITE HIGH ON
TUESDAY...AT OR ABOVE 10KFT...WHILE WINDY AND VERY WARM CONDITIONS
PREVAIL EAST OF THE DIVIDE.  THIS PATTERN WILL BE FAVORABLE FOR
ACCELERATED SNOWMELT IN THE CENTRAL MOUNTAINS ALONG WITH POSSIBLE
SIGNIFICANT RISES IN CREEKS AND STREAMS...ESPECIALLY IN THE BIGHORN
MOUNTAINS AND DOWNSTREAM RIVER BASINS.

PACIFIC COLD FRONT WILL PUSH ACROSS CENTRAL WYOMING TUESDAY
NIGHT...BUT DOWNSLOPE WESTERLY WINDS ARE EXPECTED TO KEEP SHOWER AND
THUNDERSTORM ACTIVITY MOSTLY ISOLATED WITH THE MAIN HAZARD OF STRONG
WIND GUSTS WITH THE FRONTAL PASSAGE.  IN THE WEST...SNOW LEVELS ARE
EXPECTED TO LOWER TO VALLEY FLOORS TUESDAY NIGHT WITH CYCLONIC
WESTERLY FLOW BRINGING MORE WIDESPREAD SNOW...ESPECIALLY TO YNP AND
THE TETON RANGE...INTO WEDNESDAY.   NORTH AND CENTRAL AREAS WILL
HAVE BETTER CHANCES OF RAIN AND SNOW SHOWERS LATE WEDNESDAY INTO
THURSDAY IN NW FLOW WITH H5 COLD POOL ALOFT.

&&

.AVIATION.../12Z ISSUANCE/

SOME IFR/MVFR CONDITIONS IN STRATUS AND/OR BR ACROSS JOHNSON AND
NATRONA COUNTIES EARLY THIS MORNING ARE EXPECTED ERODE BETWEEN 09Z
AND 12Z AS THE BOUNDARY LAYER DRIES A BIT AS WINDS SHIFT MORE
WESTERLY. OTHERWISE...VFR AND DRY CONDITIONS WITH RELATIVELY LIGHT
WINDS WILL OCCUR TODAY AS A QUICK MOVING UPPER RIDGE BUILDS ACROSS
THE COWBOY STATE. CONSIDERABLE HIGH LEVEL CLOUDINESS IS EXPECTED
TO DEVELOP ESPECIALLY ALONG AND EAST OF THE DIVIDE THIS AFTERNOON
WITH SOME MID LEVEL CLOUDS OVER THE NORTH. THE NEXT STORM SYSTEM
WILL APPROACH THE AREA LATE TONIGHT RESULTING IN INCREASING
CLOUDINESS OVER THE WEST...AS WELL AS INCREASING MOUNTAIN WINDS
WITH POSSIBILITY OF SOME LOW LEVEL WIND SHEAR DEVELOPING AT KCOD
AND KLND. CONTEMPLATED ADDING AT 10Z OR 11Z GROUP HAVING VCSH TO
THE KJAC TAF...BUT LOOKS LIKE THE TIMING OF SHOWER ACTIVITY WITH
NEXT SYSTEM WILL HOLD OFF UNTIL AFTER 12Z FRIDAY.

&&

.FIRE WEATHER...

A WEAK SURFACE PATTERN TODAY WILL KEEP WINDS IN CHECK FOR ANOTHER
DAY AS HIGH TEMPERATURES WARM INTO THE 60S ACROSS MANY LOWER
ELEVATIONS. FRIDAY...THE BASINS WILL CLIMB NEAR OR INTO THE LOWER
70S...AHEAD OF THE NEXT SPRING WEATHER SYSTEM DUE TO PUSH THROUGH
THE FORECAST AREA THROUGH THE DAY. WINDS WILL ALSO PICK UP TO THE
BREEZY CATEGORY ACROSS MOST OF THE FORECAST ZONES...WITH THE USUAL
WIND PRONE AREAS OF THE SOUTHERN DISPATCH ZONES...MOUNTAIN RIDGE
TOPS AND NORTHERN CODY FOOTHILLS POSSIBLY GETTING SOME ISOLATED HIGH
WINDS. IN ADDITION...BY FRIDAY AFTERNOON THERE WILL BE AN INCREASING
CHANCE FOR SHOWER AND ISOLATED THUNDER LASTING INTO THE EVENING
PERIOD. SATURDAY...HIGH TEMPERATURES WILL BE SOMEWHAT COOLER...BUT
WINDS WILL ALSO BE MORE TAME.

&&

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

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...WM
FIRE WEATHER...BRAUN










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