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000
FXUS63 KABR 250120 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
820 PM CDT Wed Apr 24 2024

.KEY MESSAGES...

- Wind gusts out of the south to southeast between 35 to near 45
  mph will be possible Thursday into Thursday night, strongest
  over north central SD and the western slopes of the Prairie
  Coteau.

- Two rounds of wetting rain will move in Thursday afternoon into early
  Saturday, and Sunday as a couple of low pressure systems near
  the area. The Probability of 48hr QPF>0.50" ending Saturday
  evening ranges from 40 to over 75%, lowest over north central
  SD.

&&

.UPDATE...
Issued at 819 PM CDT Wed Apr 24 2024

No major updates are planned this evening.

&&

.SHORT TERM /THIS EVENING THROUGH THURSDAY NIGHT/...
Issued at 336 PM CDT Wed Apr 24 2024

We remain in high pressure to our northeast and an elongated area of
low pressure organizing to our west. Relative humidity values over
southeastern SD and western MN have been able to fall into the teens
to low 20 percent range this afternoon. Winds out of the south to
southeast around 10 mph or less for most locations and ground fuels
starting to green up is helping to limit fire weather concerns.
Several hot spots noted off of satellite imagery across eastern SD
and west central MN are from beneficial fires/prescribed burns. Dry
air will be slowly exiting tonight into Thursday. There is a 20%
chance of light rain tonight over portions of eastern SD/west
central MN associated with the strong low level jet and 500mb trough
moving through the area. A dry forecast may briefly take hold around
daybreak Thursday before the next wave slides in from the southwest.
While the higher chances (30%) of rain will be in the afternoon, we
won`t be able to rule out at least a 20% chance over much of central
SD in the morning. Timing of clouds/rain could limit temperatures
from reaching around 70 degrees Thursday. The main concern Thursday
will be increasing winds out of the south to southeast out ahead the
general area of low pressure stretching from far eastern MT to
eastern CO at 18Z Thursday. Warm air advection wind forecasts are a
bit tricky, with the latest NBM diminishing winds and gusts slightly
from the previous forecast. We continued the trend in our forecast,
which still gave winds gusting near 45 mph over the favorable
locations of north central SD and the western to northwestern slopes
of the Prairie Coteau (mainly from Turton/Crandall through
Groton/Andover/Bristol/ through Claremont/Britton...or northern
Clark, Day, eastern Brown, and much of Marshall County). Will wait
to issue any Wind Advisory headlines, as confidence is lower on
being able to realize the stronger winds and higher gusts. Rainfall
wise, the focus will stay over our southern counties, as the surface
low consolidates across far southwestern NE by 09-12Z Friday.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 336 PM CDT Wed Apr 24 2024

More than half of this period will be marked an unsettled weather
pattern across our forecast area as a series of low pressure systems
move through the region. Beginning 12Z Friday, we should already be
seeing a wave of moisture shifting through the area as lead s/w
activity ahead of the parent upper low begins to organize a bit
better across parts of western NE. Model guidance among the 12Z
suite of deterministic and ensembles remains fairly aligned in
shifting this mid-lvl low and sfc reflection northeast across NE on
Friday and into the Sioux Falls vicinity by late Friday night. This
system is then progged to continue northeast toward the Twin Cities
area in MN on Saturday and into the western Great Lakes by Saturday
night. Models maintain that in this system`s overall evolution from
Friday through Saturday, it will be the most organized closer to our
region as the system occludes and then eventually opens up and
weakens as it shifts away from our area during the first half of the
weekend.

Consensus and confidence remains fairly high that a good portion of
our forecast area will continue to get in on some noteworthy
rainfall Friday and Friday night before the system begins to pull
away and chances dwindle through the first half of Saturday. NBM
probabilities of rainfall reaching or exceeding a half inch in a 48-
hour period ending Saturday evening remain in a 50-90 percent range
across the CWA. The highest probs by far are concentrated across the
James Valley and points east with at least a 75 percent chance or
higher. GEFS mean QPF for select locales across our eastern zones
sit close to or right around 1 inch of rainfall ending Saturday
evening. Mean QPF values for our western zones have had a more
noticeable fall in the latest guidance with numbers between a half
inch and three-quarters of an inch during this same time frame. PoPs
will begin dwindling by Saturday morning, although there may be some
lingering widely scattered showers around through midday and
afternoon. The 2nd in the series of disturbances will already be
taking shape across the 4-Corners region of the CONUS by the
beginning of the weekend. Some subtle differences remain among
guidance on the track and timing of this system as it shifts
northeast toward our region in similar fashion to Friday`s system.

By 12Z Sunday, this open wave or closed mid-lvl low is progged to
pull out into portions of the Northern Plains and then into the
Upper Midwest by Monday morning before heading over the western
Great Lakes and into Ontario by Monday night and early Tuesday. A
wave of moisture is set to shift northward into our area with
increasing PoPs beginning overnight Saturday night and overspreading
the forecast area during the day on Sunday. Latest guidance
continues to point at our eastern forecast zones has having the
better chances for picking up higher rainfall values. NBM prob QPF
values of reaching or exceeding a quarter of an inch in a 24-hour
period ending Monday morning are 35-65 percent range with the
highest values(>50%) again concentrated from the James Valley and
points east. This system is progged to quickly pull away from our
area, so much so that PoPs will be mostly done and gone by early to
mid morning Monday. Temperature trends will experience a gradual
cool down through the first half of this period with reading falling
below normal during the upcoming weekend thanks to extensive cloud
cover and rainfall. By the end of period(Tue-Wed), a drier trend
will take hold. Upper flow turns more quasi-zonal by the middle of
next week as temperatures begin to experience a warming trend.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 602 PM CDT Wed Apr 24 2024

Terminals KABR,KATY,KPIR,KMBG

VFR skies/vsbys are forecast regionwide through tonight.


&&

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

$$

UPDATE...TDK
SHORT TERM...KF
LONG TERM...Vipond
AVIATION...TDK