Area Forecast Discussion
Issued by NWS Riverton, WY

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
000
FXUS65 KRIW 160511
AFDRIW

Area Forecast Discussion
National Weather Service Riverton WY
1111 PM MDT Thu Jun 15 2017

.SHORT TERM...(This evening through Sunday)
Issued at 225 PM MDT Thu Jun 15 2017

Zonal west flow aloft will remain over the area through the weekend.
A series of Short wave low pressure troughs with Pacific moisture
will bring increased showers and thunderstorms Friday and Saturday
most numerous over the northern and western mountains. Temperatures will
be below normal with windy areas over and near the mountains. Weak
ridging will begin to buckle the zonal flow with decreasing moisture
and increased stability and warming on Sunday.  Winds will also decrease
on Sunday.

.LONG TERM...(Sunday night through Thursday)
Issued at 225 PM MDT Thu Jun 15 2017

As the ridge continues to build and amplify from the west,
temperatures will continue to warm Monday and Tuesday with h7
temps maxing out around 18c in Southern WY Tuesday. Tuesday will
be the hottest day of the week with highs in the low to mid 90s
over the lower elevations of the central basins east of the divide
with similar temperatures in both the Wind River and Big Horn
Basins in spite of the fact that the Big Horn Basin is lower in
elevation than the Wind River Basin with h7 temps warmer over
southern WY closer to the high over the desert SW where temps are
now topping 120F there. Johnson and natrona Counties will be in
the upper 80s along with low 70s in the valleys/basins out west
Tuesday afternoon. As the ridge approaches, the ridge will flatten
by Tuesday. A weak vort lobe will track east within the westerly
flow within the flattened ridge Tuesday. Then a more defined
northern stream shortwave will brush our CWA Wednesday. The
outlier is the Euro as it is slower with the timing of this
shortwave. Moisture with these two features will be scant so only
have isold afternoon and evening pops for mainly our northern
zones on Tue/Wed. As the ridge continues to flatten, Wednesday and
Thursday will become slightly cooler. Thursday will be dry.
Occasional westerly breezes can be expected for much of next week.
The minimum RH will be in the mid teens in Sweetwater County
early in the week, and then these low RH readings will spread
north to Central Wyoming by mid week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1110 PM MDT Thu Jun 15 2017

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

VFR conditions will prevail across the area through 18z Friday.
Isolated to scattered showers will be found mainly over Yellowstone
National Park.  A cold front will then spread widespread rain
showers and mountain obscurations south to vicinity KJAC by 20z
Friday with westerly flow aloft strengthening and areas of LLWS
developing.  MVFR conditions should prevail KJAC from around 20z
Friday and overnight.  These rain showers are not expected to make
it much further south than KBPI-KPNA Friday night.  Surface winds
will gradually diminish Friday evening with some areas of LLWS
remaining through early Saturday morning.

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR conditions will prevail through Friday afternoon.  Surface west
winds will increase ahead of a cold front that will push into the
north, vicinity KCOD-KBYG by 00z Saturday.  Scattered to numerous
rain showers will develop behind this cold front as it pushes
further south Friday evening.  Areas of lower MVFR ceilings are
expected to develop after 03z Saturday behind the cold front.  The
front will push south to a vicinity KRIW-KCPR line by 06z Saturday
and further south to near Interstate 80 by 12z Saturday.  Lower
MVFR, local IFR ceilings will be most probable along the Interstate
25 corridor, KBYG-KCPR and vicinity KCOD Friday night.

&&

.FIRE WEATHER...
Issued AT 225 PM MDT Thu Jun 15 2017

Zonal west flow aloft will remain over the area through the weekend.
A series of Short wave low pressure troughs with Pacific moisture
will bring increased showers and thunderstorms Friday and Saturday
most numerous over the northern and western mountains. Temperatures will
be below normal with windy areas over and near the mountains. Weak
ridging will begin to buckle the zonal flow with decreasing moisture
and increased stability and warming on Sunday.  Winds will also decrease
on Sunday. Afternoons should be unstable enough with strong enough
wind and mixing for very good to excellent smoke dispersal.

&&

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

$$

SHORT TERM...Baker
LONG TERM...Lipson
AVIATION...Meunier
FIRE WEATHER...Baker



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.