225
FXUS63 KUNR 121928
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
128 PM MDT Fri Jul 12 2024

.KEY MESSAGES...

-Hot this weekend with isolated storms at times, some strong to
 severe

-Elevated fire weather conditions through the weekend

-Cooler next week with isolated to scattered storms at times

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 123 PM MDT Fri Jul 12 2024

High pressure ridge over the Rockies will shift east through the
weekend, supporting hot conds. The ridge will eventually flatten
as a strong impulse will cross the the Northern Plains next week,
with cooler and unsettled conds expected then. Biggest concern
this weekend will be the heat, esp toward central SD where deeper
moisture will be in place, supporting higher apparent T`s. Thermal
ridge will move over the region Sat-Sun, supporting the warmest
temps locally with this round of heat. Have issued an adv from SW
through scentral SD as heat index`s will reach 100 or higher both
days with lows in the 60s/70s. Several weak impulses will
traverse the northern edge of the ridge leading to slight chances
for showers and storms and as sufficient moisture will be in
place. However, most storms will produce limited amounts of rain
given high based nature of storms, esp in the western half. Some
stronger storms (as well as a few isolated severe storms) will be
possible through Sat given sufficient bulk layer shear in excess
of 35 knots and enough CAPE in place at times (greater than 1000
J/kg). The better profiles of CAPE will be in place Sat as SE
flow becomes established again, supporting deeper moisture further
west. This could allow for a supercell or two off the Black Hills
or INVOF of any lingering sfc troughs. Sfc trough will push
through early Sunday, supporting drier weather as breezy northerly
flow shunts deeper moisture east of the FA. Stronger impulse will
top the ridge Monday and support a cool front into the region
with temps falling back into the 80s for highs as well as semi-
unsettled flow through much of next week. However, storm coverage
will be isolated to scattered with most places not seeing much in
the way of appreciable moisture, although slightly better LL
moisture profiles look to be in place.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1110 AM MDT Fri Jul 12 2024

Isolated showers and storms will be possible this afternoon and
evening. Locally gusty winds will be possible with any storms.
Otherwise, VFR conditions will continue through the TAF period.

&&

.FIRE WEATHER...
Issued At 123 PM MDT Fri Jul 12 2024

Elevated fire weather conditions are expected through the weekend
as hotter and drier weather continues to shift eastward into the
area. Isolated to scattered high based thunderstorms are expected
at times, but not a lot of precipitation is expected. While RH`s
will be dropping into the teens, especially for northeast WY and
lower elevations of far western SD, winds do not look to be
particularly strong at this time, except for a brief period Sunday
behind a sfc trough late in the afternoon.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from noon MDT /1 PM CDT/ Saturday to 8 PM MDT /9
     PM CDT/ Sunday for SDZ030>032-041>044-046-047-049-075>077.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...10
FIRE WEATHER...JC