Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 271636
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1036 AM MDT WED JUL 27 2016

.SHORT TERM...Today Through Friday Night

Showers over eastern Wyoming should weaken through this morning,
though a few showers will remain possible over Natrona and Johnson
counties. Models indicate another push of moisture and instability
this afternoon, with another round of isolated to scattered showers
and thunderstorms. Gusty wind and small hail will be the primary
threats with storm activity this afternoon and evening.

Again, showers over eastern Wyoming will linger through the
overnight hours. Thursday looks to be the more active day as far as
thunderstorms as an area of low pressure moves to the northeast of
the state. This system will push a cold front across the eastern
portion of the state, with cooler temperatures anticipated. Showers
are generally anticipated to remain mostly east of the Continental
Divide, with the best activity expected to be over the northern
mountains, and again over Natrona and Johnson counties. This
placement is in fair agreement with the the Storm Prediction Center,
which has indicated a marginal risk for storms on Thursday. Hail and
wind again looks to be the primary threats with storm activity.
Shower coverage will decrease Thursday night, though some threat
will persist over Johnson and Natrona counties.

A drier northwest flow is anticipated across the area on Friday,
with a diminished coverage of shower activity. Areas east of the
divide are again anticipated to see some storm threat, but coverage
remains generally isolated except over the Bighorn Mountains where
scattered storms may be found. Coverage will quickly taper off
Friday evening, with widespread dry conditions anticipated after
midnight.

.LONG TERM...Saturday through Wednesday

Saturday looks dry for most places. Isolated showers or storms in
the far west late in the day into the evening hours. Sunday the
models wish to bring in a little more moisture and a weather
disturbance moving through the flow. This should lead to more
shower and thunderstorm development in the afternoon through the
evening hours. Monday will see isolated showers and storms once
again in the afternoon and evening hours. GFS and ECMWF models
differ slightly next Tue and Wed. The GFS model takes a weather
system over the Pacific NW Tue and moves it into Montana on Wed.
The ECMWF model is weaker with this feature. The GFS is thus
giving the region isolated showers and storms Tue. The ECMWF
model has isolated activity in the far north and far south.
Will blend the solutions which gives gives isolated showers and
storms for Tue afternoon and evening. Next Wed would then be dry
as drier air moves in behind the weather system. Very warm to hot
temperatures Saturday through Tuesday and slightly cooler next
Wed.

&&

.AVIATION.../18Z ISSUANCE/

A couple weather disturbances will impact the area this afternoon
through tonight. The first one will aid in isolated to widely
scattered thunderstorms from around KCOD to KCPR while a second
disturbance will aid in evening and overnight showers and
thunderstorms from about KJAC to KCPR that as it moves east across
the area. A few stronger storms with hail, wind and frequent
lightning are quite possible late this afternoon and evening
northeast of a line from KCOD to KCPR. A new batch of showers and
thunderstorms will move into Northwest Wyoming later this evening
and move east across areas east of the divide during the early
morning hours. Generally along and north of a line from KJAC to
KCPR for these nocturnal showers/storms.

&&

.FIRE WEATHER...

Afternoon showers and thunderstorms with threats of gusty wind will
continue for the next few days. A near continuous threat is
anticipated for Natrona and Johnson counties, with showers
potentially lingering through the overnight hours. A cold front will
sweep through northeastern Wyoming today, helping to cool off
temperatures today and Thursday. Additionally, this front will
increase instability for areas east of the divide on Thursday,
resulting in a threat for some stronger storm activity Thursday
afternoon.

&&

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

&&

$$

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


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