411
FXUS65 KRIW 052013
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
213 PM MDT Fri Jul 5 2024

.KEY MESSAGES...

- Fire Weather Watch in effect Saturday from 2 PM MT to 8 PM MT
  for low relative humidity and strong gusty winds across
  portions of Fremont and Natrona counties.

- Isolated to scattered showers and thunderstorms possible this
  evening. Increased coverage of showers and thunderstorms
  expected tomorrow (Saturday) late afternoon and overnight.

- Long period of well above-normal temperatures and dry
  conditions expected through the upcoming week.

&&

.DISCUSSION...
Issued at 201 PM MDT Fri Jul 5 2024

Satellite imagery shows a disturbance moving south along the lee
side of the northern Rockies this afternoon with a decent cu field
developing across central and eastern Wyoming. While a brief shower
or thunderstorm is possible this afternoon and early evening,
confidence is low in any major impacts except for gusty winds and
lightning in storms. Confidence increases in rain showers and
thunderstorms tomorrow afternoon and overnight, especially across
north-central Wyoming, as another disturbance ejects southward along
the lee side of the northern Rockies. Primary concerns with these
showers and thunderstorms would be gusty winds and lightning. In
addition, ahead of the frontal passage tomorrow, there is a
60-80% chance of critical fire weather conditions where fuels
are cured across portions of Fremont and Natrona counties. Due
to this, a Fire Weather Watch is in effect.

Wyoming remains on the eastern edge of the ridge across the western
CONUS through the weekend, keeping conditions warm, mostly dry,
and breezy. Tuesday into Wednesday the ridge begins to shift
more eastward, increasing temperatures, and continuing the
mostly dry pattern. Wednesday through the weekend, temperatures
are forecast to be well above-normal, potentially record
breaking a few afternoons. NAEFS percentiles has 700 mb
temperatures near 90-99th percentile Wednesday through at least
the weekend. While overnight temperatures will still drop into
the low 50s, this prolonged period of above- normal heat does
create some concern for heat, especially for sensitive and
vulnerable populations. Forecast high temperatures are in the
80s to 90s across much of central and western Wyoming, reaching
potentially 100+ degrees in portions of the Bighorn Basin
starting Thursday.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1041 AM MDT Fri Jul 5 2024

Northwest flow continues through the TAF period, which will bring
some rain showers to northern Wyoming this afternoon/evening as well
as Saturday afternoon/evening. Terminals impacted by these showers
will be KCOD/KWRL/KCPR, mainly this evening. Have included
TEMPO/PROB30 groups to account for these rain showers. Conditions
should remain VFR even as showers pass over these terminals and at
other terminals where skies will remain mostly clear. A breeze will
develop this afternoon, but gusts will only be 15-20 knots on
average through this afternoon/evening. Wind becomes light overnight
before increasing again late Saturday morning as the next wave in
the flow drops down into northern Wyoming.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for
the latest information on icing and turbulence forecasts.

&&

.FIRE WEATHER...
Issued at 224 PM MDT Thu Jul 4 2024

Fire Weather Watch in effect for portions of Natrona and Fremont
counties Saturday afternoon for low relative humidity values and
strong gusty winds ahead of a frontal passage. Additional long
period of elevated to near-critical fire weather conditions
expected through next week with well above-normal temperatures
and dry conditions. Weaker winds will be the main limiting
factor in critical fire weather conditions.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Saturday afternoon through Saturday
evening for WYZ280-283.

&&

$$

DISCUSSION...Gross
AVIATION...Rowe
FIRE WEATHER...Gross