Area Forecast Discussion
Issued by NWS Riverton, WY
FXUS65 KRIW 250830
Area Forecast Discussion
National Weather Service Riverton WY
230 AM MDT MON JUL 25 2016
.SHORT TERM...Today Through Wednesday Night
Generally quiet conditions to continue today, with a few showers
possible over the central and northern mountains as a weak
disturbance works to move through the area. These showers could
increase in coverage during the evening hours as the weak
disturbance moves eastward. Gusty wind looks to be the primary
threat with any storm activity today.
A more zonal flow pattern then begins to establish itself starting
Tuesday morning. This westerly flow aids in the development of a
somewhat unsettled pattern, with afternoon showers and thunderstorms
possible. Models are not in exceptional agreement when it comes to
shower coverage with this flow pattern, which encourages the
isolated coverage currently in the forecast period. Temperatures
will cool somewhat over the next couple of days, with some areas
reaching into the upper 80s by Wednesday afternoon.
High pressure works to begin rebuilding over the area by Tuesday
evening, with a strengthening area of high pressure noted over the
desert southwest. As this ridge strengthens, expect a return of a
more northwesterly wind by Wednesday evening. This flow pattern
may encourage a wind increase across central Wyoming on Wednesday
evening, especially across the Wind River Basin.
As has been with the last several days, the bigger concerns across
the area remains fire weather conditions. Tomorrow may be another
active day for area wildfires, with warm, dry, windy, and unstable
air settling over the the area today. The Fire Weather discussion
will contain additional details.
.LONG TERM...Thursday Through Monday
A quasi-stationary cold front will be set up east of the Divide
Thursday and Friday. This front combined with some low-level
moisture north and east of it, as well as a couple of disturbances
in the northwest flow will result in isolated to scattered
convection along and east of the Divide. The best day for convection
looks to be Thursday with the stronger shortwave. West of the Divide
and over the south should remain dry.
Models are showing the northern fringe of some monsoonal moisture
spreading north and northeastward from the Great Basin into the area
this upcoming weekend into early next week. At the same there could
be some northern stream energy which could come into play. Saturday
looks to be the driest of the 3 days with better shot for isolated
coverage across much of the area Sunday and Monday.
Seasonal temperatures are expected Thursday and Friday east of the
Divide, with above average temperatures west of the Divide. Saturday
through Monday look to be 5 to 10 degrees above average across much
of the area.
VFR conditions will prevail today and tonight. Isolated showers or
storms in southern WY after 19z through 03z. Isolated showers or
storms over far northern WY from 21z through 05z. Outflow wind gusts
to 30 knots will be the main hazard near showers or storms.
Smoke will continue to be an issue near active wildfires. This will
impact visibility at times in the valleys through 18z. Smoke plumes
are expected this afternoon into the evening which will send columns
of smoke across portions of the sky.
Another enhanced fire activity day is setting up for areas east of
the Continental Divide. Warm, dry, and unstable air will set up
generally across the area, with some locations also seeing the
development of gusty afternoon wind. This combination will leave
some areas susceptible to explosive fire growth, and a Red Flag
Warning has been issued for this afternoon and evening. A similar
scenario is favorable on Tuesday, with increased coverage of gusty
wind possible. Overall, it looks to be a potentially active couple
of days for already present fires across the area.
Red Flag Warning from noon today to 9 PM MDT this evening for