726
FXUS63 KUNR 262319
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
519 PM MDT Fri Jul 26 2024

.KEY MESSAGES...

- Better chances for thunderstorms this afternoon/evening and into
this weekend, with a few strong to severe storms possible.

- Hot again on Saturday, but cooling a bit for Sunday.

- Very hot and dry weather expected to develop again as next week
  progresses.

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 138 PM MDT Fri Jul 26 2024

Water vapor shows upper ridge extending through the Four Corners,
Central Plains, and Upper Midwest. Upper low is near the ALTA/SASK
border with trof extending through the Northern Rockies, with an
ejecting short wave near the Central Rockies. At the surface, cold
front is through about 2/3rds of our zones. There is some monsoonal
moisture streaming overhead, but the lower layers remain very dry.
Hot temperatures remain, especially across south-central SD ahead of
the cold front.

The cold front will stall out this afternoon south/east of the Black
Hills, and will be the focal point for thunderstorms this
afternoon/evening as short wave ejects out of the Central Rockies
and through the region. Broad bulk shear is rather weak, but higher
right along the cold front, and most CAMs are showing a few stronger
storms along the front. Severe wind gusts look to be the main threat
given high storm bases. Most guidance is rather wet later this
afternoon/evening, primarily across the western 1/3rd of SD, but
not sure how quickly the lower levels may be able to moisten.

Upper low will move slowly across the central Canadian provinces
this weekend, with disturbed southwest flow across the Northern
Plains. Another ejecting short wave and cold front will move through
during peak heating on Saturday, with more storms possible. Shear is
a little better Saturday so some hail may be possible, but severe
wind gusts would again be the main threat. Hot temperatures expected
again Saturday, but should cool for Sunday behind the cold front.

The unsettled pattern looks to continue into the early part of next
next week, but upper ridge looks to get reestablished to our west as
the week progresses, leading to more hot weather with less
chances for precipitation.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 516 PM MDT Fri Jul 26 2024

VFR conditions should continue for much of the period.
Scattered thunderstorms have developed across a line from KIEN to
KPHP, these storms will continue to develop and increase in
coverage across western SD into northeastern WY as the evening
progresses. Strong and erratic wind gusts may be encountered near
any storms.

Increasing haze/smoke from wildfires may also cause some reductions
in vsbys at times late in the period, especially from northwestern
SD to northeastern WY.


&&

.FIRE WEATHER...
Issued At 138 PM MDT Fri Jul 26 2024

Elevated fire weather conditions continue today, although RH is a
little higher behind the cold front pushing through the region. A
better chance of storms arrive later this afternoon and evening,
especially across the western 1/3rd of SD. The lower levels of
the atmosphere are still quite dry, but not as dry as yesterday,
so widespread dry lightning is not expected.

Hot weather returns on Saturday, with RH dropping into the teens for
northeast WY and far western SD, but winds do not look
particularly strong. Another round of thunderstorms is possible
in the afternoon/evening.

Unsettled weather continues into early next week with mainly above
average temperatures. Very hot and dry conditions are likely to
return as next week progresses with an upper ridge rebuilding to our
west.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 7 PM MDT /8 PM CDT/ this evening for SDZ032-
     043-046-047-049-077.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Dye
AVIATION...Wong
FIRE WEATHER...Dye