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000
FXUS65 KCYS 221806
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1206 PM MDT Mon Jul 22 2019

.UPDATE...
Issued at 1201 PM MDT Mon Jul 22 2019

...Please see latest 18Z aviation discussion...

&&

.SHORT TERM...(Today & Tonight)
Issued at 356 AM MDT Mon Jul 22 2019

Areas of fog & low stratus have become fairly widespread along and
east of the Laramie Range this morning, due to deep boundary layer
moisture & strong low-level upslope flow. High-resolution guidance
shows southeasterly surface winds persisting well into the mid and
late afternoon hours, suggesting stratus could very well take much
of the day to erode especially near the Laramie Range. This likely
will limit high temperatures today, so we opted to go with several
degrees below consensus guidance once again. Shower & thunderstorm
potential is a bit uncertain, but chances may begin to increase by
mid/late afternoon especially just west of the Laramie Range where
a lack of stratus will aid in some destabilization. Appreciable 0-
6 km shear of 30-40 knots will support storm organization if storm
activity is able to develop, but with warm advection aloft through
the day capping could very well be an issue, especially along/east
of the Laramie Range where stratus may linger. The bottom line, we
may have a few strong/severe storms, but overall confidence is low
at this time.

.LONG TERM...(Tuesday - Sunday)
Issued at 356 AM MDT Mon Jul 22 2019

Upper-level ridging builds into the region on Tuesday with 500 hpa
heights rising to 594-596 dam by 00z Wednesday. The ridge flattens
quickly, giving way to very active quasi-zonal flow aloft from Wed
through the remainder of the period. Several waves embedded within
the flow will help contribute to daily chances for convection each
afternoon/evening. The overall coverage & intensity of storms will
depend on the specific timing and track of individual waves, which
is very difficult to discern at this time. Some good news: Overall
severe threats will be low w/ modest shear profiles, but expect to
see a few stronger storms through the week given excellent low-lvl
moisture and resultant moderate instability. Daytime highs will be
near normal through the period, potentially being tempered some by
showers and thunderstorms in the area.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1201 PM MDT Mon Jul 22 2019

After being locked under a thick cloud deck and fog for most of
the morning, ceilings are finally lifting to VFR conditions. Low
clouds will continue to taper off and move out by 2 PM.
Thunderstorms are then possible this afternoon with a few being
strong to severe mainly for sites along and west of I-25.
Conditions will be become much drier towards the end of the
period.

&&

.FIRE WEATHER...
Issued at 356 AM MDT Mon Jul 22 2019

Fire weather concerns will remain low this week. Temperatures will
be near normal, but abundant low-level moisture will help keep RHs
outside of critical thresholds. Showers & thunderstorms are likely
each afternoon/evening over the next few days, especially over the
higher terrain.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

$$

UPDATE...CW
SHORT TERM...CLH
LONG TERM...CLH
AVIATION...CW
FIRE WEATHER...CLH