000
FXUS65 KCYS 260452
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1052 PM MDT Thu Apr 25 2024

.KEY MESSAGES...

- Scattered to numerous showers and thunderstorms are expected
  across southeast Wyoming and the western Nebraska Panhandle
  today and tonight. A few storms may be strong to locally
  severe, especially east of I-25. The primary hazards will be
  large hail and damaging wind gusts, although an isolated
  tornado or two will be possible. The potential will exist for
  cold-core funnel clouds as well.

- An extremely active weather pattern persists through the
  weekend with widespread stratiform rain w/ embedded thunder
  likely for most areas from Friday through Sunday.

- Accumulating snow is expected at elevations above 8000 feet,
  with the potential for 12+ inches in the Snowy and Sierra
  Madre Ranges from Friday through Sunday. The I-80 Summit
  between Laramie and Cheyenne will be very close to the main
  transition zone between rain and snow. Travel impacts remain
  possible, mainly from Friday night through Saturday.

&&

.MESOSCALE...
Issued at 245 PM MDT Thu Apr 25 2024

Latest GOES visible imagery shows numerous showers and
thunderstorms that have developed west of the Laramie Range
early this afternoon along with initiation along the dryline
positioned west of Cheyenne northeast through Chugwater. This
dryline has not propagated eastward as quickly as initially
forecast with the early clearing of morning cloud cover.
Additionally, early morning storms that tracked from western
Carbon Co up through Douglas has left an outflow boundary now
extending south through Goshen Co. This will lead to a potential
area of enhanced convergence in the North Platte River valley
near the WY/NE border for new storm development later this
afternoon right on the gradient of convective inhibition to the
east. Latest observations show dew points in the 50s near
Sidney up through Banner Co and points towards the northeast.

Based on latest CAM guidance, areas of concern will be from
Torrington through Scottsbluff and potential towards Alliance
areas late this afternoon into this evening. Forecast soundings
would support marginally severe hail likely around 1-1.5 inches
with the strongest cells with 500-700 J/kg of CAPE in the hail
growth region. Additionally, surface winds in the river valley
are modeled to by more east-southeasterly enhancing low-level
shear and short-lived tornado potential with any discrete
storms. However, stronger 0-6 km shear is present along the I-80
corridor in the NE panhandle as the core of 500mb flow aloft
has weakened over the last 24 hours per latest RAP analysis,
limiting stronger shear farther north in our CWA.

As better lift continues to arrive overhead, more widespread
storm coverage will continue with embedded stronger cells. Main
weather hazards overnight will transition towards heavy rainfall
and localized flooding, especially over the southern NE
panhandle that may see repeated rounds of precipitation with the
initial storm development in our area in addition to storms
closer to the surface low traversing north of the CO/WY border.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1048 PM MDT Thu Apr 25 2024

Low pressure system over northwestern Kansas will continue to
bring some light rain to the southern Nebraska Panhandle
airports through the early morning hours. Looking at various
short term guidance...looks like flight conditions will stay VFR
to maybe MVFR in heavier showers. Dry across southeast Wyoming
overnight into Friday morning before next round of showers and
storms develop Friday afternoon. Need to be on the lookout for
lowering ceilings in the Panhandle Friday evening as winds turn
northeasterly.

&&

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

&&

$$

MESOSCALE...MB
AVIATION...GCC