Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 240905

Area Forecast Discussion
National Weather Service Riverton WY
305 AM MDT Sat Mar 24 2018

.SHORT TERM...Today through Monday night
Issued at 247 AM MDT Sat Mar 24 2018

A Pacific low is moving into the Northwestern States today which
will propagate a quick moving shortwave across our western areas.
Snow accumulations will be below advisory levels in both the western
mountains and valleys though the Tetons may get close. Sunday
morning the 700mb low arrives over Southwest WY. This will begin to
spread precip further east of the divide, starting as rain for
central WY and to the north and east areas. As the low pushes
northeastward across the state Sunday night snow occurs in the
Wind River and Big Horn Basins through Johnson and Natrona
Counties. Models have indicated that the low will slow a bit
before leaving the state which could bring significant snow
amounts to the Bighorn Mountains and Johnson County so a Winter
Weather Watch has been issued. Snow will continue through the day
Monday before tapering of Monday evening.

.LONG TERM...Tuesday through Saturday
Issued at 247 AM MDT Sat Mar 24 2018

Tuesday looks dry and cool for the region with highs in the 30s and
40s. Isolated afternoon snow showers in the NW WY mountains cannot
be ruled out. The next weather system impacts the north Tue night
with some light snow. The precip develops over the central and south
Wed afternoon into Wed night. Precip will a mix of rain and snow
here. Snow pellet showers cannot be ruled out as well. High temps
Wed in the 30s and 40s with temps falling into the 30s in the
central zones in the afternoon as the cold air pushes southward.
Snow showers Wed night, decreasing after midnight from north to
south. Thursday will see dry weather for most places with lingering
snow showers in the northern mountains and rain or snow showers
across parts of Johnson county. High temps Thursday in the 40s to
around 50. Friday now looks dry and milder over the region with
highs in the upper 40s to upper 50s. Next Saturday could see some
rain and snow return to the NW WY mountains and the northern Bighorn
mountains. The GFS and ECMWF models show this moisture increase
ahead of a weather system that may move into WY next Saturday night.
Dry weather elsewhere next Saturday with breezy to windy areas and
highs in the 50s to lower 60s.


.AVIATION...For the 12Z TAFS through 12Z Sunday
Issued at 247 AM MDT Sat Mar 24 2018

West of the Divide...KBPI/KJAC/KPNA/KRKS Routes

VFR conditions will prevail across the area through 12z with isold-
sct snow showers occasionally obscuring the mountains.  A cold front
will push into KJAC area around 18z Saturday, and progress across
western Wyoming in the early afternoon.  Numerous MVFR/IFR snow
showers will develop ahead of and along the front 12z-18z Saturday
vicinity and north of a KAFO-KDUB line with mountains becoming
mostly obscured.  Gradual improvement will occur across NW Wyoming
21z Saturday-03z Sunday, but scattered snow showers are expected to
develop across SW Wyoming 00z-06z Sunday, with occasional IFR
conditions at KRKS.  Another round of sct-nmrs MVFR/IFR snow showers
is expected to move into the west, vicinity and north of a KEVW-KPNA
line, 08z-12z Sunday.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Routes

Fog and low clouds at the KCPR airport will lift by 15Z.
Otherwise, VFR conditions are expected to prevail through 00z
Sunday. Surface S to SW winds will increase to 15-25 knots across
much of the area by 18z Saturday with higher speeds from vicinity
50NE KRKS-KCPR. A cold front will push south across northern
Wyoming Saturday evening with scattered MVFR, isolated IFR shsnra
developing primarily vicinity and south of a KLND-KRIW line. Areas
of MVFR/IFR ceilings and light snow are expected to develop
behind the cold front along and east of the Bighorn Mtns to 60SM
west of KCPR 06z-12z Sunday.


Issued AT 247 AM MDT Sat Mar 24 2018

An upper level shortwave will bring snow to the western mountains
and valleys today, but will leave east of the divide warm and dry
until later this evening. Precipitation will be prevalent from
tonight through the weekend across the forecast area. Gusty
southwest winds will focus mainly in the mountains this morning
before moving down to lower elevations in the afternoon. Winds
across the area will slow considerably once evening arrives.



Winter Storm Watch from Sunday evening through Monday afternoon
for WYZ008>011.



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