Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 172311
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
511 PM MDT TUE MAY 17 2016

.SHORT TERM...(This Evening Through Wednesday Night)
Issued at 212 PM MDT Tue May 17 2016

20z surface analysis had high pressure from the upper Midwest
into eastern CO. Return flow continues to develop from west to
east across the CWA with a decent CU field given strong solar
insolation this afternoon. Water vapour had upper ridge across the
northern Plains into central Canada and upper low spinning across
the southwest US.

Tonight through Wednesday night, upper low over the southwest US
moves east and weakens as another upper low drops into southwest
Canada creating westerly flow aloft over the CWA. Increasing low
level return flow expected as lee trough develops and surface high
moves east. Modest low level jet develops tonight across northeast
WY into far western SD, but predicted minimum temperatures suggests
boundary layer will remain largely decoupled save for the higher
elevations of the Black Hills / Foothills. A bit of SBCAPE expected
over the Black Hills Wednesday afternoon, but increasing MLCIN and
no clear shortwave will preclude putting PoPs into forecast.
Stronger low level jet develops Wednesday night across southern SD
which may result in some ACCAS east of the Black Hills. Temperatures
will be increasingly pleasant and finally near normal.

.LONG TERM...(Thursday Through Tuesday)
Issued at 212 PM MDT Tue May 17 2016

Upper low settles over the Pacific NW and stalls out late in the
week with ridging over the plains. Mostly quiet wx and warm
temperatures are expected for Thursday and Friday, but can`t
totally rule out an afternoon shower or thunderstorm over the
Black Hills and possibly northeast WY Thursday and Friday as
southwest flow aloft edges into the area.

Chances for showers and thunderstorms will increase through the
weekend into early next week as the upper trough moves into the
region. Active SW flow will develop across the region with
possibly a fast moving upper low affecting somewhere across the
nrn plains to start the work week. Much uncertainty remains as
model solutions have been diverging. Temperatures will remain
above average over the weekend, with some highs in the 80s across
the plains. More seasonable temperatures should return early next
week.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)
Issued At 510 PM MDT Tue May 17 2016

VFR conditions are expected through the forecast period.

&&

.UNR Watches/Warnings/Advisories...
SD...None.
WY...None.
&&

$$

SHORT TERM...Helgeson
LONG TERM...13
AVIATION...7



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