Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 220746
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
146 AM MDT MON AUG 22 2016

.SHORT TERM...(Today Through Tuesday Night)
Issued at 125 AM MDT Mon Aug 22 2016

Broad upper ridge covers the central CONUS, with the next trough
pushing into the Pacific Northwest. Skies are clear over the
northern plains. Surface trough is moving into the region, and
winds are generally southerly ahead of it. Some breezy
southwesterly downsloping winds over the northern foothills are keeping
temperatures in the 70s there, while the rest of the area is in
the 50s and 60s.

Upper and thermal ridge axes will cross the area today, resulting
in very warm temperatures in the 90s and around 100 over central
SD. As surface low slowly passes through, westerly winds will
increase across northeastern WY and southwestern SD, with breezier
southwest winds over south central SD. Gusty winds over south
central SD are expected to continue overnight, keeping that area
in the upper 60s for lows. Areas farther north and west will be in
the 50s.

Upper trough will begin moving through the northern plains on
Tuesday, bringing a cold front through the region. Northwest winds
will become breezy across the western SD plains. Conditions will be
generally dry and stable on Tuesday, although some instability and
moisture over far south central SD may allow for a few showers and
thunderstorms to develop there and eastward in the afternoon and
evening. Highs will range from the 70s across northeastern WY and
the Black Hills to the lower 90s across south central SD.

.LONG TERM...(Wednesday Through Sunday)
Issued at 125 AM MDT Mon Aug 22 2016

Progressive but amplified flow expected in the period. A strong
cold front will bring fall like temps to the area once again wed-
thur. Otherwise, a slow warming trend is anticipated into the
weekend. Unsettled westerly flow will bring chances for showers to
the region wed night into Friday. Limited moisture per westerly
flow with poor to nonexistent gomex return flow will only support
a couple tenths of an inch of precip at most with each round of
shra. Hence, overall dry conds will persist.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 125 AM MDT Mon Aug 22 2016

VFR conds through the period. LL wind shear will be
possible on the SD this morning.

&&

.FIRE WEATHER...
Issued At 125 AM MDT Mon Aug 22 2016

An upper level and thermal ridge will peak Monday,
bringing a deeply mixed boundary layer and very dry minimum relative
humidity values. Readings from 8-15% are expected across the
southwest third of the area Monday afternoon and evening with 15-25%
across the rest of the region. Expect gusty winds to mix down across
the very dry areas of northeastern WY and southwestern SD today, so
will upgrade to a Red Flag Warning. Additionally, stronger southwest
winds with gusts near 35 mph are forecast for south central SD. With
min RH values near 15% on the western side of this zone, will
include south central SD in Red Flag Warning as well.

A cold front will slide through the area Tuesday with gusty
northwest winds on the SD plains most of the day. Still appears that
minimum RH values near 20% will preclude headlines at this point.

&&

.UNR Watches/Warnings/Advisories...
SD...Red Flag Warning from noon today to 7 PM MDT this evening for
     SDZ263-265.

WY...Red Flag Warning from noon today to 7 PM MDT this evening for
     WYZ259-298.

&&

$$

SHORT TERM...Pojorlie
LONG TERM...JC
AVIATION...JC
FIRE WEATHER...Pojorlie



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