Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 041613 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1013 AM CST Thu Mar 4 2021

.UPDATE...
Issued at 1009 AM CST Thu Mar 4 2021

Leftover fog between KABR/KMBG should gradually burn off this
morning, leaving a mostly sunny day for the region. Given
soundings and e/se boundary layer winds, have to wonder if we are
a bit high concerning Max temps. For now only a slight tweak down.
Rest of the forecast looks good.

&&

.SHORT TERM...(Today through Friday Afternoon)
Issued at 448 AM CST Thu Mar 4 2021

An upper ridge will continue to draw up unseasonably warm air into
the region today and Friday. The biggest forecast challenge in the
short term remains how high the temperatures will climb during the
day.

At the sfc today, the region is sandwiched between high pressure
over the Great Lakes and low pressure over the Rockies. This sets up
moister southeast flow. While this is not a truly favorable
direction for record to near record highs, mid-levels remain very
dry with no cloud cover. Winds will also be a bit stronger by
afternoon than on Wednesday for additional mixing. Therefore, nudged
temps toward 90th to 95th percentile...well into the 50s and 60s.

For Friday, high pressure builds back in across the east. There will
be ample moisture at 925 mb after today`s southeast flow to result
in some more widespread morning fog under the inversion. That said,
believe some models are overdoing the cloud cover, or at least its
ability to linger. Drier air in northwest flow remain aloft and the
inversion should break by noon. So, while temperatures may not rise
as quickly the first half of the day, expect prime daytime heating
hours to be mostly cloud-free given there are not shortwaves of note
in the upper flow. Collaboration with neighbors, though, put temps
at a blend of 90th and 75th percentiles.

.LONG TERM...(Friday Evening through Wednesday)
Issued at 448 AM CST Thu Mar 4 2021

A stout upper-level ridge will continue to make for May-like
temperatures through the weekend and into early next week, before a
few changes arrive.

Beginning Saturday morning, sfc high pressure will be centered
across the Mississippi Valley, retreating further east due to
incoming low pressure from the west. There`s some question about the
presence/extent of low-level cloud cover, but thinking is that it
should dissipate by the afternoon as southerly breezes increase.
Given sunshine, confidence is high for temperatures to climb well
above average, even into record-territory. A couple daily records
have already been set earlier this week in less anomalously warm air
aloft than is forecasted. Have collaborated with neighbors to use
the 90th percentile of inherited guidance, placing highs from 60 to
70+ across the CWA.

A similar story unfolds on Sunday temperature-wise, despite a
shortwave and associated sfc low and cold front that`s forecast to
work through the Northern Plains throughout the day. The resulting
wind shift, from southerly to northwesterly across the CWA, will
lead to even better mixing. Record warmth with highs in the 60s,
locally warmer, is again possible, aided again by the ongoing drought
and associated dry air (D2/Severe across portions of central SD and
D1/Moderate and D0/Abnormally Dry elsewhere). Wind gusts both
Saturday and Sunday could climb into the 20 to 30+ mph range in
response to the tightened pressure gradient. This, combined with the
dry fuels and RH in the 20 to 30% range, means elevated fire danger.

Highs in the 50s and 60s will continue Monday as the upper-level
ridge remains. A western CONUS trough encroaches on the Northern
Plains Tuesday, leading to southwest flow aloft. If the resulting
sfc low pressure tracks to the north placing the CWA in its warm
sector, another particularly mild day lies in store. There is still
a good deal of uncertainty regarding the overall evolution of this
system, so while precipitation is possible, details remain fuzzy.
Cooler air moves in on the backside of this system by mid-week, but
there`s uncertainty about just how cool (not all that much cooler?).

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 448 AM CST Thu Mar 4 2021

Terminals KABR,KATY,KPIR,KMBG

After some patchy morning fog, mainly across the east, expect VFR
conditions through this evening. Fog could redevelop early Friday
morning, as well.


&&

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

$$

UPDATE...TDK
SHORT TERM...Wise
LONG TERM...Lueck
AVIATION...Wise



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