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FXUS63 KABR 291127 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
627 AM CDT Wed Mar 29 2023

.UPDATE...
Issued at 624 AM CDT Wed Mar 29 2023

See updated aviation discussion below.

&&


.SHORT TERM...(Today through Thursday Afternoon)
Issued at 312 AM CDT Wed Mar 29 2023

The main forecast challenge in the near term revolves around
precipitation chances on Thursday ahead of an approaching storm
system. An upper level shortwave currently over the region will exit
to the east this morning, leaving northwest flow in its wake this
afternoon into this evening. Ridging builds over the region
overnight and Thursday morning before southwest flow ahead
of a western United States trough develops in the afternoon.

At the surface, high pressure will be the dominant feature over the
Northern Plains today, then it tracks to the east tonight, with the
region becoming situated between it and low pressure approaching
from the west. After cooler temperatures today and tonight, the
warmer flow should result in warmer temperatures on Thursday. The
low to the west will reach the western High Plains by late Thursday
afternoon, and the question then becomes whether or not
precipitation associated with its associated warm front extending
from the low to over Iowa will make it to the northeastern CWA
Thursday afternoon. For now, will keep just some small POPs across
that area. Model soundings do indicate a brief window where there
may be some freezing precipitation during the late Thursday
afternoon hours.

High temperatures today will range from the upper teens across west
central Minnesota and northeastern South Dakota, to the mid 30s
across south central South Dakota. Low temperatures tonight will
range from the single digits across west central Minnesota and
northeastern South Dakota, to the mid 20s across south central South
Dakota. Highs on Thursday will range from the lower 30s along the
North Dakota/South Dakota border, to the mid 50s across south
central South Dakota.


.LONG TERM...(Thursday Evening through Tuesday)
Issued at 312 AM CDT Wed Mar 29 2023

Friday looks to be a mess. Initially we have NAM/GFS BUFKIT profiles
indicative of freezing drizzle, with about 4-5kft thick stratus just
a few degrees above freezing at the top and below freezing for the
lowest 1-2kft mainly along and east of the James (shallower or non-
existent west of the James). The warm layer rapidly cools as
profiles saturate so a brief period of actual freezing rain before
the p-type shifts to snow.  We continue to see better and better
alignment between deterministic members on the track and timing, and
precipitation bullseyes that form during the day Friday, though
there is still a bit of confidence issues generated by GEFS plumes
(an inch QPF difference in highest and lowest members with a good
spread in between) while a good number of EC ensemble postage
stamps QPF bullseyes missing or much less intense compared to
deterministic guidance. Seeing better confidence in winds as well
with BUFKIT mixed winds in the NAM into the low 40s (kts) while
the GFS is still a bit excessive in the 50s (kts). Its hard to
judge how efficiently we will mix with a 12-15mb 6 hour pressure
rise on the backside of a low that drops 18mb/24 hours along with
a 20 to 25mb gradient across the state...on top of cold advection.
Blowing snow model suggests impacts will be very temperature/wind
and snowfall rate dependent initially during the day Friday (not
to mention the non-diurnal temperature profile likely, and a
potential coating of drizzle) with a trend for wetter snow...but
as we cool and winds increase, impacts are more probable even if
snowfall rates come down.

We get some milder air Sunday and then a weak cold frontal passage
Monday... so mixing opportunity with milder air means some of us
will finally get to see 40 degrees again.

At the tail end of the forecast we will have yet another Colorado
low system to deal with, similar to the Friday storm system. At this
point not much to tell other than another potentially impactful
system is headed our way...and right now there is some decent
continuity with this one for these timescales.


&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday Morning)
Issued at 624 AM CDT Wed Mar 29 2023

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area today and tonight.
Look for southeasterly winds to increase into the 15 to 25 knot
range late tonight across central South Dakota.

&&


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

$$

SHORT TERM...Parkin
LONG TERM...Connelly
AVIATION...Parkin