Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 110904

Area Forecast Discussion
National Weather Service Cheyenne WY
304 AM MDT Tue Aug 11 2020

.SHORT TERM...(Today and tonight)
Issued at 300 AM MDT Tue Aug 11 2020

Forecast challenges deal with mainly fire weather concerns across
our western fire weather zones...followed by severe thunderstorm
chances in the Panhandle today. See fire weather discussion below.

Currently...Frontal boundary lays roughly along the
Wyoming/Nebraska stateline this morning at 2AM. East of the
front...seeing 60 Tds. Southeast Wyoming plains stations reporting
Tds in the 50s...while west of the Laramie Range...30 Tds reported
at Rawlins. Looks like a low level jet has set up over the
Panhandle with southerly winds gusting in the 30 to 35kt range on
METARS out there. Looks like the stage is set for possible severe
storms in the Panhandle today.

Latest HRRR and NMM Hires guidance showing storms developing along
the Laramie Range after 1PM today and move east through the
afternoon. Looks like strong winds will be the main hazard as
forecast soundings showing high based storms. The exception to
this may be the northern Panhandle (Alliance and Chadron) where
better moisture and great shear develops this afternoon for large
hail to possibly be the main hazard. 21Z NAM MUCAPE up near 2500
J/KG over both DAwes and Box Butte Counties. SPC has a Slight
Risk area identified in this area with a Marginal Risk outlined
across the rest of the Panhandle.

To our west across Carbon...Converse and Albany Counties...dry and
breezy expected again today. Previously issued Red Flag Warnings
look good today. GFS 700mb winds around 20-25kts through the day.
Very high mixing on soundings up to 500mbs...possibly higher as we
have seen gusts in to mid to upper 30 mph range across Carbon and
Albany Counties the past several days with similar winds.

.LONG TERM...(Wednesday through Monday)
Issued at 300 AM MDT Tue Aug 11 2020

Similar fire weather concerns for Wednesday As ridge axis shifts
east and much drier air moves into our eastern fire weather zones
all the way to the Panhandle. Not seeing the strong winds out
there in the Panhandle just right yet though. But zones west look
to see 25-30kts once again Wednesday. Did issue a Fire Weather
Watch for the same zones we have in todays Red Flag Warning. Later
shifts will have to watch out for expansion of fire weather
headlines east...if sounding show stronger mixing.

Another front expected Thursday afternoon to backdoor us across
the Panhandle and northern zones. Looks like Thursday will see
stronger winds over Wednesday out ahead of that front. This may be
the day all of the CWA ends up in fire headlines. 850mb winds in
the Panhandle forecast at 35kts on the GFS. If this looks similar
tonight...will likely issue a Fire Weather Watch Wednesday morning
for the Panhandle.


.AVIATION...(For the 06Z TAFS through late Tuesday evening)
Issued at 522 PM MDT Mon Aug 10 2020

Main forecast concern for tonight will be low stratus clouds and fog
over western Nebraska. Confidence is low for IFR or lower conditions
due to high dewpoint depressions and poor high res model agreement.
Thunderstorm chances for tomorrow look low, so kept out of the TAFs
for now, but a few thunderstorms are possible from KSNY northward to

HAZARDS/WEATHER TRENDS: VFR conditions will prevail across most
locations through the rest of tonight and into early Tuesday. There
is a 10 to 20 percent chance for MVFR or near-IFR CIGS across the
western Nebraska terminals between 09z and 15z Tuesday morning.
Diurnal winds will increase after 15z across the southeast Wyoming
terminals with gusts around 30 knots possible at KRWL.


Issued at 300 AM MDT Tue Aug 11 2020

A frontal boundary lays across the Nebraska Panhandle this morning
with a ridge of high pressure from western Colorado to
northwestern Wyoming. Between these two features...winds are
expected to remain strong across western Converse...all of Carbon
and northern Albany Counties today and tomorrow. Red Flag Warnings
and Fire Weather Watches are in effect for FWZs 301 through 308
today and Wednesday for gusty winds and low humidity. These gusty
winds and low humidity expected to continue occurring each day
through at least the weekend.


WY...Red Flag Warning from 11 AM this morning to 8 PM MDT this
     evening for WYZ301>308.

     Fire Weather Watch from Wednesday morning through Wednesday
     evening for WYZ301>308.



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