644
FXUS63 KABR 241725
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1225 PM CDT Wed Apr 24 2024

.KEY MESSAGES...

- Wind gusts out of the south to southeast between 35-45 mph will
  be possible Thursday into Thursday night, strongest across
  South Dakota, east of the Missouri River.

- A more active and wet pattern develops by the end of the week
  into early next week as a couple of low pressure systems move
  through the region delivering rainfall to most of the forecast
  area.

- Probability of 48hr QPF>0.50" ending Saturday evening ranges
  from 50 to 90%, highest around and east of the James River
  Valley.

&&

.UPDATE...
Issued at 1224 PM CDT Wed Apr 24 2024

No significant changes have been needed to the ongoing forecast.
The main adjustments have been related to the clouds and
potentially sprinkles/but mainly virga over south central SD.
Another adjustment today is the lower dewpoints over portions of
far northeastern SD into west central MN. Winds in that area
remain light today, limiting fire weather concerns.

&&

.SHORT TERM /TODAY THROUGH THURSDAY AFTERNOON/...
Issued at 334 AM CDT Wed Apr 24 2024

At 3 AM CDT, skies are clear/mostly clear, with just some cirrus
working over western South Dakota. Surface high pressure centered on
the eastern Dakotas and Minnesota is creating a light and variable
wind environment, which under this clear sky is helping to promote
ideal radiational cooling conditions. Temperatures have fallen, so
far, into the 30s to low 40s across the CWA, and should continue to
slip a few more degrees prior to sunrise (~6:30 AM CDT).

Not much has changed for the short term period, compared to
yesterday. Still looks like a decent return flow pressure gradient
should set up across the central/western Dakotas by the end of the
day today, encouraging a southerly wind of 15 to 30 mph with some
higher gusts to develop across said area by 00Z Thursday. Overnight,
these southerly LLJ winds spread over to the border of the Dakotas
and Minnesota. At the same time, energy aloft and some modest mid-
level WAA/moisture advection could set off a few elevated showers
overnight, particularly along the leading edge of the
developing/shifting LLJ. Guidance continues to point at Thursday as
being a potential wind advisory-type of day with sustained winds
around 30 mph, and gusts occasionally getting up into the 40 to 45
mph range. BUFKIT does show mixing heights getting up to somewhere
between 4k and 5k feet where top end gusts are up into the 35 to 40
knot range, particularly east of the Missouri River valley region of
the CWA.

Went (warmer) closer to NBM50th for high temperatures today and
Thursday, given plain NBM`s recent lackluster performance on
temperatures (too cold). Plenty of sunshine today, for at least the
first half of the day, to help boost temperatures up into the 70s
for much of the CWA, despite the ongoing green-up. Thursday is
expected to have a bit more cloud cover to deal with although
probably not overcast the entire day, as well as perhaps the first
isolated/widely scattered afternoon rain showers developing of the
upcoming wet period. So, widespread 70s on Thursday may be a bit
tougher to come by, despite the ongoing low level southerly WAA
pattern.

&&

.LONG TERM /THURSDAY EVENING THROUGH TUESDAY/...
Issued at 334 AM CDT Wed Apr 24 2024

Confidence remains high on a parade of lows affecting our area for
the long term bringing rain/storms. Starting off Thursday evening,
Clusters are in agreement with the intensity of the negative tilted
trough and position as it will be over the Southwestern U.S, leaving
the Northern Plains on the PVA side of it and surface low forming
over Colorado. Both the trough and low will continue its path
northeast, with the trough and low forecasted to be over the Central
Plains by 12Z Friday. Ensembles indicate an increase in moisture
through Friday morning with NBM showing this well, with pops 70-80%
over the CWA 00-12Z Friday.

Through the day Friday into Friday night this trough, and developing
mid level low, will continue to push northeast and center itself
over parts of the Central and Northern Plains with the surface low
occluding over the same area, as the system becomes more stacked.
This is when we will see our highest pops as the CWA will be
positioned north of the warm front and then in the wrap around
portion/trowel of the low. Pops range from 95-99% 12Z Friday-00Z
Saturday and 75-95% 00Z-12Z Saturday as we really see that surge in
moisture. Better lift/energy will be over the central Plains but we
will have some lift (more shear than lift) to get some thunderstorms
Thursday afternoon/evening and Friday. CSU seems to be the most
aggressive between CIPS/SPC as it shows a 15% probability for our
eastern and southeastern CWA Friday.

Pops decrease to around 30-50% Saturday afternoon/night as the low
continues its northeastern track over MN/WI area and we are left in
more of a surface trough behind the low, which is why we have
continuing pops. As this low departs we look ahead to the next
system as it looks to follow a similar track. The trough settles
over the Southwestern US Saturday evening with a Colorado low
forming. 12Z Sunday and onward we start seeing differences in exact
placement and intensity of the system between the Clusters. NBM
indicates a general increase in pops of 50-75% (highest east of the
Mo River) pops Sunday and decreasing west to east Monday as the
system departs.

Confidence is increasing for this moisture as NAEFS still shows
PWAT values from 00Z Friday-00Z Saturday 90-97.5% above climo with
values 0.75-1" over the CWA as WV transport really show the
return flow surging northward ahead of the first low as mentioned.
Even GEFS Plumes indicate a mean for PW around an inch Friday for
ABR/ATY which matches up to NAEFS. QPF wise, EC EFI indicates
0.5-0.7 for QPF Thursday night through Friday night, with a shift
of tails of zero east of the Missouri River. WPC Plumes indicates
mean QPF through Saturday evening at 1.10" for KABR with KATY/K8D3
around an inch. GEFS plumes for QPF is similar. Latest NBM
indicates Prob of 48hr QPF> 0.50" ranges from 50-90%, ending
Saturday evening, highest over James River Valley and eastward.
Additional accumulations expected Sunday.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1224 PM CDT Wed Apr 24 2024

Terminals KABR,KATY,KPIR,KMBG

VFR ceilings and visibility will continue over the next 24 hours.
The main concern will be winds increasing out of the south to
southeast. Low level wind shear is possible at both PIR and ABR
during the overnight hours as winds above the surface are around
35-40kts.

&&

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

$$

UPDATE...KF
SHORT TERM...Dorn
LONG TERM...MMM
AVIATION...KF