Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 232110
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
310 PM MDT SAT JUL 23 2016

.SHORT TERM...(This evening through Monday night)
Issued at 310 PM MDT Sat Jul 23 2016

Afternoon water vapor loop showed the CWA between a upper trough
moving across the northern Rockies and another lifting northeast
across the northern Great Plains/Upper Midwest. Mesoanalysis/radar
analysis placed a weak front just east of I-25 with north-northeast
winds across the Nebraska Panhandle and far eastern Wyoming plains.
As predicted by the short-range models, isolated convection formed
along and just north of the Colorado border. Much of this activity
is high-based with inverted-v soundings indicating potential for
gusty outflow winds to 50 mph along with occasional lightning.
The convection should remain confined to far southeast Wyoming,
but a few could sneak into far southwest corner of Nebraska late
this afternoon. Convection should dissipate later this evening.

The short term model consensus shows the west-southwest flow aloft
veering to west-northwest and amplifying somewhat Sunday through
Monday as the southern CONUS upper high retrogrades westward across
the Four Corners region. Diurnal convection under this flow regime
will be limited to the higher terrain and nearby plains of southeast
Wyoming. Models prog a upper level disturbance to move southeast
across the Dakotas late Monday which may trigger isolated thunderstorms
over northwest Nebraska. Sunday will be about 10 degrees cooler than
today across the plains with highs in the 80s. Temperatures warm
into the upper 80s-mid 90s Monday with the amplifying ridge.

.LONG TERM...(Sunday night through Saturday)
Issued at 310 PM MDT Sat Jul 23 2016

West-northwest flow will be overhead at the start of the long
term period, veering more northwest by Friday as the upper high
retrogrades westward. A fairly steady stream of Pacific moisture
with embedded shortwave disturbances will remain overhead through
midweek, meaning there will be chances for showers and
thunderstorms each day across the region. Still looks like
Wednesday and Thursday could be the best chance for strong/severe
storms with increased llvl moisture, shear, and upslope flow
behind a cold front dropping south across the region late
Tuesday/early Wednesday. Temperatures will trend cooler, back to
more seasonable readings for this time of year. A reinforcing
front on Friday will maintain chances for t-storms over the
forecast area.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1151 AM MDT Sat Jul 23 2016

A cold front dropping south across the plains today will shift
west-northwest winds to the north-northeast by this evening.
Isolated thunderstorms are possible along and east of the Laramie
Range late this afternoon and into the evening as winds become
more upslope. May see storms continue overnight across the plains,
but confidence is low that this scenario will pan out so will keep
t-storm mention out of the tafs for now.

&&

.FIRE WEATHER...
Issued at 310 PM MDT Sat Jul 23 2016

Warm, breezy and dry conditions will continue for much of east
and south central wyoming through monday with a ridge of high
pressure along the continental divide. Fire weather danger will
remain high in these areas. Across portions of southeast wyoming
and western Nebraska, there wil be slight chances for afternoon
and evening showers and thunderstorms. As the ridge shifts further
west next week, a northwest flow aloft and a couple of upper level
disturbances will increase chances for late day showers and
thunderstorms east of the Laramie Range.

&&

.CYS Watches/Warnings/Advisories...
WY...None.
NE...None.
&&

$$

SHORT TERM...MAJ
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...MAJ


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