Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 211801 AAB

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
101 PM CDT Mon May 21 2018

Issued at 100 PM CDT Mon May 21 2018

See the updated aviation discussion below for the 18Z TAFS.

UPDATE Issued at 1121 AM CDT Mon May 21 2018

Increased pops across the southeast cwa into the afternoon based
on the latest radar trends. Still should remain mostly cloudy
across much of the cwa today. May have to adjust the highs down
for today based on the cloud cover. Updated forecast.


.SHORT TERM...(Today and Tonight)
Issued at 303 AM CDT Mon May 21 2018

First, dropped any mention of fog as we are under an airmass that is
seeing cloud cover across most of the CWA, while underneath moisture
advection has been slowed by a NBL with winds only around 3-5mph.
Dewpoint depressions here are also between 10 and 20F.

For today the dissipating upper low is responsible for a degree of
cloud cover across the area, along with some light showers around
the Watertown area. BUFKIT profiles show some degree of cloudiness
lingering across the area but with late-May sunshine there should be
some breakup, with best forcing for showers moving north and east
while weakening. The main impact will be on temperatures and
followed previous shifts differentiation between the warmer west and
more cloud covered east with the James valley as the delineator.

.LONG TERM...(Tuesday through Sunday)
Issued at 303 AM CDT Mon May 21 2018

The period opens with the Dakotas sandwiched between a departing
high and a lee side low. As southerly return flow increases,
moisture will increase across the region. Coupled with warm temps in
the 80s under a building upper ridge, there will be sufficient
instability to generate some showers and thunderstorms by Tuesday
evening. Persistent weak sfc low pressure and shortwave activity
under the ridge will keep showers and thunderstorms in the forecast
through the end of the work week. Additional energy will be added on
Thursday night as a sfc front moves through with an upper trough.

Conditions are expected to dry out but remain warm next weekend as
another upper ridge builds in on Saturday and high pressure
dominates at the sfc. The dry conditions will be short-lived.
Another lee side low develops on Monday that will help set off more
showers and thunderstorms across central SD late in the day.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 100 PM CDT Mon May 21 2018

KABR/KATY will continue to carry a BKN to OVC MVFR cig into this
afternoon, persisting longer at KATY into the evening. Some light
shras will continue to be possible at KATY early this afternoon.
Improved cigs expected at both terminals this evening. However,
this will be temporary at KATY as an MVFR cig/IFR vsby is
anticipated overnight through sunrise Tuesday morning.

KPIR/KMBG will see VFR conditions prevailing through this entire
TAF forecast period.




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