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000
FXUS63 KUNR 171120
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
520 AM MDT Wed Apr 17 2024

.KEY MESSAGES...

- Breezy with rain showers today into this evening, snow showers over
  the higher elevations of northeast Wyoming and the Black Hills.


- Unsettled, windy, and colder weather expected for the rest of the
  week and into the early part of the weekend.

- More seasonable temperatures Sunday into early next week.

&&

.DISCUSSION...(Today Through Tuesday)
Issued at 250 AM MDT Wed Apr 17 2024

Current surface analysis shows strong low pressure over southern
MN, with another area of low pressure over southeast SK and a cold
front stretching south-southwest across eastern MT and northern
WY. Upper level analysis shows low over southern MN as well, with
a low over southern SK into northwest MT. Strong upper jet
wrapping around the system to the northwest. Skies are clearing
out across the far eastern CWA, with clouds increasing across
western areas. Regional radars show areas of rain showers and
higher elevation snow showers across south central MT into
portions of northern WY. No pcpn noted across northeast WY yet.
Temps are mostly in the upper 30s and 40s with relatively light
west to northwest winds in most areas.

Cold front to the northwest will push through the area later this
morning and afternoon, with breezy northwesterly winds in most areas
behind it. Winds will be a bit stronger across northwest SD, with
some gusts to around 40 mph likely late this morning and afternoon.
Shortwave energy rotating around the low to the north will bring
increasing chances for rain and higher elevation snow showers
through the day from northeast WY to the Black Hills and southern
SD. Pcpn amounts are not expected to be much, mostly a tenth of an
inch or less, but portions of northeast WY to the Black Hills will
likely see a tenth to a quarter inch of liquid pcpn. The higher
elevations of the northern Black Hills will mostly see that in the
form of snowfall, with up to 3 inches expected from O`Neill Pass to
Cheyenne Crossing and Lead late this morning into the early evening.
Any accumulations elsewhere over the Black Hills into northeast WY
will mostly be an inch or less. High temps today will be in the 50s
across the SD plains, upper 30s and 40s elsewhere, with 30s over the
higher Black Hills. Pcpn should exit most area by midnight.

Thursday and Friday will be cool and windy as tight pressure
gradient develops between low to the northeast of the region and
strong high pressure over southwest Canada. Advisory criteria wind
potential looks to be near 50 percent or higher across the northwest
into west central SD plains for Thursday. The high will gradually
settle southeast over the northern Plains Friday night and Saturday.
Drier weather is expected late week into the weekend, but another
disturbance could clip at least southwestern parts of the area later
Friday into Saturday, with a few rain/snow showers possible.

Milder air returns for Sunday and next week as surface high pushes
east of the region. Temps will rise back to near or slightly above
average levels for Sunday and the first half of next week, with
highs in the 50s and 60s. Near zonal flow aloft will likely bring a
couple of shortwave disturbances across the area, mainly Sunday
night/Monday and again midweek, with chances for showers.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Thursday Morning)
Issued At 518 AM MDT Wed Apr 17 2024

Rain and snow showers moving into northeastern Wyoming late
tonight will spread into western South Dakota later this morning.
MVFR/local IFR conditions expected with the precipitation.
Conditions will improve late this afternoon.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...26
AVIATION...10