954 
FXUS65 KRIW 050020
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
620 PM MDT Sun Aug 4 2019

.SHORT TERM...This evening through Monday
Issued at 109 PM MDT Sun Aug 4 2019

A shortwave over E ID this afternoon will continue its east-
northeast track and trigger thunderstorms across W WY this 
afternoon. Modest instability remains in place today. Strong 
thunderstorms with wind gusts over 40 knots will be possible, but 
the main threat will be locally heavy rain/flash flooding again. 
Based on convective activity from Saturday, isolated severe winds 
gusts cannot be ruled out. Precipitable water values will once again 
be 150 to 200% of normal with this wave. The stronger instability 
will be over Johnson and Natrona counties this, however, storms are 
not forecasted to reach these areas until after 00Z Monday (more 
than likely between 03Z and 06Z). 
  
A ridge axis will build over the PACNW tonight into Monday, putting 
the Cowboy State on the east side of this ridge. This will turn the 
upper level winds to the west-northwest. A weak cold front will make 
its way over areas east of the Divide Monday. Apart from the already 
moist airmass being in place today, dewpoints will be in the lower 
to middle 40s west of the Divide Monday and in the lower to middle 
50s east of the Divide. Expect widespread convection across the 
County Warning Area Monday afternoon, especially east of the Divide. 
Stronger storms will be possible over these areas, with the 
northwest flow overhead, steep lapse rates and abundant moisture as 
contributing factors.

.LONG TERM...Monday night through Sunday
Issued at 109 PM MDT Sun Aug 4 2019

High pressure ridging will continue across the region through the 
work week and into next weekend with a series of shortwaves bringing 
showers and thunderstorms. Isolated to scattered convective activity 
will develop in the afternoons, and then potentially last into the 
late night hours. As usual, the best chances will be in and near the 
mountains. Daytime high temperatures will be in the upper 70s and 
low to mid 80s in the west, with the central basins and southern 
regions in the upper 80s and low 90s at times. 

&&

.AVIATION...For the 00Z TAFS through 00Z Tuesday
Issued at 620 PM MDT Sun Aug 4 2019

Scattered showers and storms will continue through 06Z Monday, 
especially over the far northwest, before decreasing in coverage 
after 06Z Monday. The threat for wind gusts over 40 knots, along 
with brief MVFR to IFR conditions, will continue through 03Z Monday. 
Isolated showers will continue east of the Divide through 09Z, as 
these showers exit eastward. VFR conditions will occur through the 
period. Convective activity will be widespread Monday afternoon, 
with most of the activity occurring east of the Divide. Stronger 
thunderstorms are expected in these areas, with strong wind gusts, 
hail and locally heavy rain. Isolated to scattered thunderstorms 
will occur between 20Z and 23Z Monday west of the Divide. 

&&

.FIRE WEATHER...
Issued AT 109 PM MDT Sun Aug 4 2019

Shower and thunderstorm activity is expected to be a little more 
widespread across the region this afternoon and into the evening. 
Due to adequate monsoonal moisture, any thunderstorms that do 
develop will be efficient rain makers, so dry thunderstorm chance 
remains low. Surface humidity will be low this afternoon but should 
remain above critical thresholds. Winds will be modest through the 
day, generally 10 mph or less. Expect strong erratic winds form any 
thunderstorm. More storms in store mainly east of the Divide for 
Monday afternoon.|

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LaVoie
LONG TERM...Hulme
AVIATION...LaVoie
FIRE WEATHER...Hulme