Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 280908
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
308 AM MDT THU JUL 28 2016

.SHORT TERM...Today Through Saturday Night

Lingering showers over northern Wyoming this morning will persist
through the morning hours. Models demonstrate a further
destabilization of the atmosphere during the mid morning hours, with
the most impressive CAPE and lifted index values occurring generally
through the mid afternoon. Therefore, it appears that today will be
an earlier show for thunderstorm activity. Gusty wind and small hail
may accompany storms through the early afternoon. Based on
instability parameters, a rogue strong to severe storm may be
possible, as the environment seems a bit more primed than it has the
last couple days. The most active storms look to occur across
eastern Wyoming, especially Natrona and Johnson counties. However,
some higher instability parameters also nudge into the eastern
portion of the Big Horn Basin.

Instability weakens during the late afternoon hours, though some
thunderstorm activity will remain possible through the late evening
hours. Shower coverage will diminish after midnight, with storms
generally only lingering over the northern mountains by Friday
morning. The pattern continues with an increase in storm coverage
during the afternoon hours. Model diagnosed instability is not as
impressive as Thursday, but gusty wind and small hail will remain a
possibility. Storm activity will weaken with loss of daylight Friday
evening, with widespread dry conditions anticipated by early
Saturday morning.

Storm activity on Saturday looks best during the evening hours, and
generally for areas west of the Continental Divide. The atmosphere
is anticipated to stabilize after midnight, with just a few rain
showers possible during the overnight hours.

Temperatures will remain slightly cooler today across the area, with
only portions of southwestern Wyoming expected to reach into the
90s. Warming conditions are expected through Saturday, with 90s
returning to the central and eastern basins on Saturday.

.LONG TERM...Sunday through Thursday

Models have some moisture in the area Sunday which will lead to
scattered showers and storms in the afternoon into the evening.
High temps very warm to hot. Monday looks dry for most places
with isolated showers/storms in the mountains and far south. Still
very warm to hot on Monday. Per the GFS model, a weather system
is forecast to move through the Pacific NW states Tuesday. Then
it moves across the Northern Rockies Tue night and through
Northern Montana Wednesday. The ECMWF model is quicker Tue into
Tue night but then has a second disturbance pushing through
Montana Wed. Will keep the isolated showers and storms on Tuesday
afternoon and early evening. Very warm to hot once more on Tue.
Then isolated showers and storms in the far south Wed. Rest of the
region to be dry Wed behind a cool front that will pass through
late Tue night into Wed morning. Highs Wed a little cooler most
places with best cooling in the north half of WY. Next Thursday
looks dry over the region. High temps seasonably warm.

&&

.AVIATION.../12Z ISSUANCE/

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

Smoke from the Cliff Creek Fire near Bondurant may bring MVFR vsbys
to vcnty KBPI-KPNA 12z-16z Thursday. Otherwise, drier air will
bring VFR conditions and unlimited ceilings to all terminal sites
through 12z friday with some west to northwest breezes in the
afternoon. A dry cold front will result in a wind shift from the
NE along the Interstate 80 corridor, vcnty KRKS, Thursday evening.

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

An upper level disturbance will continue to bring scattered showers
and thunderstorms vcnty and north of a KCOD-KWRL-KCPR line through
12z.  A decrease in this activity will occur 12z-20z, then showers
and thunderstorms will blossom across most areas Thursday afternoon
and early evening.  The strongest storms are expected along and east
of the Interstate 25 corridor where isolated storms may produce
large hail and wind gusts over 40 knots.  Most of this activity will
move out of the area by 03z Friday.

&&

.FIRE WEATHER...

Slightly cooler temperatures anticipated across much of the area
today. Showers and thunderstorms will be possible for much of the
area east of the Continental Divide, especially during the late
morning and early afternoon hours. Gusty wind to 50 mph may occur
with some storms, and some higher gusts are not out of the question.
Additionally, hail and brief periods of heavy rain may round out
storm activity today. Another round of afternoon showers and
thunderstorms possible on Friday under slightly warmer temperatures.
Further warming is anticipated on Saturday, when storm coverage will
mostly move to areas west of the Continental Divide.

&&

.RIW Watches/Warnings/Advisories...None.

&&

$$

SHORT TERM...Branham
LONG TERM...AR
AVIATION...AEM
FIRE WEATHER...Branham



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