Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 190441

Area Forecast Discussion
National Weather Service Cheyenne WY
1041 PM MDT Sun Jun 18 2017

.SHORT TERM...(This evening through Tuesday)
Issued at 227 PM MDT Sun Jun 18 2017

Upper ridging over the desert SW will continue to build northward
through Tuesday. Temps will warm each day through Tuesday and by
Tuesday afternoon 700 mb temps of 16-18C will be in place over our
western counties. Temperatures will rise well into the upper 80s
to lower 90s outside of the mountains on Tuesday under generally
sunny skies and only slightly breezy conditions west of the
Laramie Range. Not much of a risk of convection through Tuesday
night as significant warming and drying aloft will occur
underneath the upper ridge. Moisture will start to slowly return
over the high plains by Tuesday night as a more SE`ly wind
direction begins to prevail at the surface. GFS tries to develop
some isolated convection over the mountains Tuesday night as a
minor shortwave passes over the top of the ridge but think the
unfavorable diurnal timing and dry atmosphere should limit POP
below 20 percent.

.LONG TERM...(Tuesday night through Sunday)
Issued at 227 PM MDT Sun Jun 18 2017

Seasonal pattern in place for Wed-Thu with a cold frontal passage
and resultant cool down in store Fri-Sun. Zonal flow on Wednesday
turns northwesterly as two shortwaves dive southeast into the
plains. High temps on Wed-Thu will warm into the 80s with WAA at
the llvls. Medium range models suggest perhaps two surges of
cooler air late in the week. The first of which is expected to
occur Thursday night with the second on Friday night. Highs on
Fri-Sun will be 10-15 cooler compared to earlier this week. In
fact, highs on Saturday will likely not get out of the 60s above
5000 feet or so. Aside from the typical summertime convection
chances over the mountains on Wednesday, the best chance for
precipitation will occur with the second frontal push on Friday
night/early Saturday.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1039 PM MDT Sun Jun 18 2017

Wyoming TAFS...VFR. Wind gusts to 22 knots at Laramie from 16Z to

Nebraska TAFS...VFR. Wind gusts to 24 knots from 15Z to 01Z.


Issued at 227 PM MDT Sun Jun 18 2017

A warming trend will occur through the middle of the week. RH
values will drop to 15 percent or below each afternoon west of the
Laramie Range but fuels remain green and winds should be
relatively light which should preclude a significant fire weather
threat. A strong front will move into the area from the north and
west late in the week which may bring increased precipitation
chances and cooler temperatures.




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