316
FXUS63 KUNR 191048
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
448 AM MDT Thu Sep 19 2024

.KEY MESSAGES...

- Very windy conditions will continue over northwestern South
  Dakota into the afternoon, with winds diminishing late
- Elevated fire weather conditions continue through Saturday
- Generally dry conditions the next several days

&&

.DISCUSSION...(Today Through Wednesday)
Issued at 111 AM MDT Thu Sep 19 2024

Water vapor shows upper low over southeastern SASK, and next upper
trof digging into BC. A cutoff low is noted along the CA coast. At
the surface, low center is over southeast SASK with trof/front
extending southward through the Plains. Tight pressure gradient
creating some gusty westerly winds, especially over northwest SD.

Stacked low currently over southeast SASK will slowly move east,
with dry westerly flow extending through SD. Advisory level winds
expected to continue across northwestern SD into the afternoon
before relaxing. Current wind advisory looks good. Highs in the
70s to lower 80s.

Temperatures will warm 5-10 degrees for Friday with dry westerly
flow aloft continuing as aforementioned upper trof along the BC
coast shifts into the Northern Rockies. Associated cold front will
then move through late Friday and drop highs into the 60s/70s for
Saturday. A few -shra not out of question late Saturday across our
far southern zones in closer proximity to the cold front.

General large scale trof will dominate our wx through early next
week, with temps close to average and mostly dry conditions
continuing. Trof will shift east with upper ridge amplifying
through the Rockies by the middle of next week with warmer temps
likely returning.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Friday Morning)
Issued At 446 AM MDT Thu Sep 19 2024

VFR conditions are expected through the forecast period except
for local MVFR CIGS near the SD/MT/ND border before 15z. Gusty
west-northwest winds will continue/redevelop today with the
strongest gusts (40-45kts) over northwest SD.

&&

.FIRE WEATHER...
Issued At 111 AM MDT Thu Sep 19 2024

Elevated fire weather conditions will continue today through
Saturday across the region. Min RHs today will be in the 20s to
lower 30s. Gusty westerly winds today, especially across northwest
SD, will lead to near critical conditions there. On Friday, drier
air returns with Min RHs in the teens to mid 20s. Near critical
conditions will likely develop over parts of northeast WY and far
southwest SD where winds may gust over 20 mph. On Saturday, gusty
northwest winds will develop behind a cold front, but RH`s will
rise back into the 20 and 30s.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 3 PM MDT this afternoon for SDZ001-002-
     012>014-025-072-073-078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Johnson
AVIATION...Helgeson
FIRE WEATHER...Johnson