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498
FXUS63 KABR 241954
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
254 PM CDT Sat Jun 24 2017

.SHORT TERM...(This Evening through Sunday)
Issued at 254 PM CDT Sat Jun 24 2017

Forecast challenges include low temperatures tonight and
precipitation chances Sunday afternoon.

Currently, under a partly to mostly sunny sky, temperatures are
warming through the 60s and in some places into the 70s. Breezy to
windy northwest winds also continue throughout the region at this
time.

The unseasonably cold airmass in place throughout the region will
remain through Sunday, as steering winds aloft continue to direct
cool/dry high pressure southeastward out of Canada. Sunday morning
low temperatures could be flirting with record territory once again
in some spots (see PNSABR). Much will depend on how long cloudiness
sticks around over northeast South Dakota and wc MN and where winds
go light and variable/calm for the longest overnight. Surface high
pressure Sunday morning should be centered over the Missouri River
valley region.

Water Vapor imagery reveals a couple shortwaves embedded within the
northwest flow pattern aloft over Alberta and southern Saskatchewan
that will likely be over this cwa by Sunday afternoon, bringing some
low end chances for rain showers/isolated thunder. Augmented the
previous shift`s enhancements with latest available hourly CAM
output for afternoon pops coverage/timing. Also, per deterministic
and ensemble thermal progs, much below normal (2 standard
deviations) temperatures persist for Sunday high temperatures again,
too.


.LONG TERM...(Sunday Night through Saturday)
Issued at 254 PM CDT Sat Jun 24 2017

A 1026mb high pressure will move into the Dakotas early Monday
morning allowing for favorable radiational conditions yet again.
This high pressure slowly drifts southeast with return flow
developing by Tuesday. The gradient across the area increases with
about a 16-20mb gradient across the state, so again will increase
winds above blended guidance. GFS BUFKIT mixed winds are again
topping out in the 30-40kt range so close to advisory level.

While not a great fetch for gulf moisture, the GFS depicts a narrow
plume of higher 850mb dewpoints extending into the region, in part
thanks to those strong conveyor winds. Warming 700mb temperatures,
between +10 and +13C should result in capped conditions however. The
strong winds will decouple Tuesday night into a 50-60kt low level
jet. This is ahead of a shortwave, which has sped up slightly in the
12Z suite of model runs. The combination of these two features,
combined with cooling 700mb temperatures, will result in convective
instability, with strong low level shear, and the potential for
severe storms - although jet stream winds are only around 40kts.

The front clears our area early Wednesday so the potential for storms
drops off quickly. The upper flow is more zonal with the low
circulation just to our north, with several weak waves moving in
from the Pacific Northwest - and while not terribly unstable with
temperatures at/below average and low low level humidity - mid level
clouds and precipitation will provide additional chances for
moisture across the region late in the work week and for the
weekend.


&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1223 PM CDT Sat Jun 24 2017

KPIR and KMBG should remain in good VFR conditions throughout the
TAF valid period. Prevailing broken/overcast VFR conditions
should also continue at KABR and KATY through at least 03Z this
evening before any chance of clearing can set up. There remains the
potential for an isolated afternoon/evening rain shower, mainly
at or near the KATY terminal. Breezy northwest winds in the 15 to
30 knot range have developed and will likely persist through the
early evening hours before diminishing below 15 knots by 06z
Sunday.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

SHORT TERM...Dorn
LONG TERM...Connelly
AVIATION...Dorn