Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 221518 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1018 AM CDT Tue Aug 22 2017

Issued at 1017 AM CDT Tue Aug 22 2017

No major updates needed in this rather tranquil wx pattern.


.SHORT TERM...(Today through Thursday Afternoon)
Issued at 329 AM CDT Tue Aug 22 2017

The surface high currently stretching across the western Dakotas
will slide over central SD/NE by 15-18Z today, and continue across
NE through tonight as the ridge slowly exits eastern SD. Otherwise,
at 500mb, northwestern flow will remain through the period, as a
larger trough over much of eastern Canada and the northeastern
quarter of the U.S. Southerly winds will be on the increase Wednesday
behind the surface low, and ahead of a lee trough over MT and
eastern WY. Expect temperatures to rise into the upper 70s to upper
80s, with the warmest readings west of the MO River. The pressure
gradient will increase for Thursday as strong high pressure
dominates the weather map from northern Manitoba through MT/WI/IL,
and the trough remains to our west.

.LONG TERM...(Thursday Evening through Monday)
Issued at 329 AM CDT Tue Aug 22 2017

Will initially start with an upper ridge overhead and high pressure
to the east. A weak wave will be undercutting the ridge, resulting
in a lee low to our south, with low level easterly flow across South
Dakota. The upper ridge breaks down with an upper trough across
western Canada and 500mb westerlies, while in the low levels flow
becomes more southerly with a weak low moving northeast. We remain
cut off from gulf moisture, however some recycled southwest monsoon
moisture, after drifting across the west for a few days, will get
pulled into the region. Mid level temperatures are not terribly
warm, +6 to +8C - so we will see elevated moist adiabatic lapse
rates and the potential for surface based convection Friday. Winds
within the profile are rather weak however. A weak low level jet may
keep the convection ongoing into Saturday morning. A weak northwest
flow shortwave will follow for additional chances Sunday - though
confidence by this point is very low. After that, the upper ridge
begins to influence the areas weather for the start of next week.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 615 AM CDT Tue Aug 22 2017

VFR conditions for all terminals.




SHORT TERM...Connelly
AVIATION...Connelly is the U.S. government's official web portal to all federal, state and local government web resources and services.