982
FXUS65 KCYS 161145
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
545 AM MDT Tue Jul 16 2024

.KEY MESSAGES...

- Widely scattered storms possible Tuesday afternoon. Increasing
  moisture Wednesday will support strong to possibly severe
  thunderstorms Wednesday afternoon. Daily chances for
  precipitation continue through the rest of the week.

- Warm mid-week before cooling trend begins for the weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 335 AM MDT Tue Jul 16 2024

Latest GOES WV imagery shows a convective complex across central
KS/NE ongoing early this morning from earlier convection
originating in eastern CO/WY associated with a shortwave passing
overtop the southwest CONUS upper level high. Remnant outflow
boundaries with these systems will likely keep the focus of
higher low-level moisture and best storm coverage east of the
CWA late this afternoon. However, widely scattered storms may
still develop along the higher terrain early this afternoon and
spreading across adjacent plains through early this evening.
Overall, instability profiles will be quite limited across much
of the CWA, but do improve late this afternoon across the
northern NE panhandle that could support sustaining a stronger
cell moving southeast out of the Black Hills as some CAMs
suggest. Temperatures will be a few degrees cooler than Monday
with 700mb temps slightly dropping to ~12-14C behind Monday
evneing`s frontal passage, but still looking at afternoon
temperatures in the mid-80s to low-90s.

Storm chances and coverage increase headed into Wednesday as
southeasterly flow will return higher dew points along and east
of the Laramie Range. The surface high near the Canadian border
will begin to slide south into the north-central CONUS with an
upslope setup across our area as another shortwave rounds the
top of the upper level ridge across the western CONUS. Steeper
mid-level lapse rates with improving low-level moisture will
support MLCAPE values between 700-1400 J/kg based on the latest
HREF IQR. Flow is fairly unidirectional above the low-level
southeasterly flow, but bulk shear values would support a few
strong storms to develop off the Laramie Range and immediate
foothills. SPC has highlighted most of the Front Range with a
Day 2 Marginal Risk for severe thunderstorms.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 335 AM MDT Tue Jul 16 2024

Upper-level ridging will develop once again over the western
CONUS Thursday through most of the long term forecast. This
ridge is progged to bring warmer temperatures to southeast
Wyoming and western Nebraska once again, but should be cooler
than this previous weekend. 700mb temperatures will only
increase to the 15C mark under the ridge on Thursday leading to
surface temperatures in the mid-80s to mid-90s. This ridge will
remain overhead for Friday as well, with a 500mb high centered
over the Four Corners region and advecting in monsoonal
moisture. Precipitable water will surge well over an inch for
portions of the Panhandle with closer to an inch over southeast
Wyoming. With several vorticity maxima traversing through the
ridge, precipitation looks likely both Thursday and Friday
evening, with Friday having the better chance for wider-spread
precipitation. As a result of the additional precipitation and
cloud cover expected for Friday, temperatures will be cooler in
the low-80s to low-90s across the region.

Saturday and Sunday both look cooler as the upper-level ridge
retrogrades slightly back to the west and colder air floods down
from Canada. Northerly to northwesterly flow aloft will remain for
both days, leading to the potential for precipitation chances in the
afternoons. A large fetch of northerly winds will be present from
southern Canada to northern Arizona, further promoting the cooler
temperatures. Temperatures on Saturday are expected to be in the
low- to upper-80s, with upper-70s to mid-80s expected Sunday. Kept
PoPs fairly low for these two days, between 20 and 30%, as afternoon
showers and storms will be difficult to track down at this time. The
cooler temperatures look to remain through the early week as the
strong northerly flow aloft remains.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 539 AM MDT Tue Jul 16 2024

VFR conditions currently across area terminals with mostly clear
skies outside of lingering mid-level cloud cover over the NE
panhandle. Winds will continue to turn northerly through this
morning ahead of widely scattered showers and storms developing
near the higher terrain early this afternoon. Kept VCTS for
southeast WY terminals along with KBFF this afternoon with
gusty, erratic winds possibly in the vicinity. Confidence in
storms in lower for remaining NE panhandle terminals, but still
possible through early this evening so will need to continue to
monitor latest trends. Winds will begin to turn easterly early
this evening and southeasterly early Wednesday morning with
increasing low-level moisture backing up against the Laramie
Range. Could see low ceilings develop at a few sites, including
KSNY, early Wednesday morning, but HREF is only showing low
probabilities at this time.

&&

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

&&

$$

SHORT TERM...MB
LONG TERM...AM
AVIATION...MB