319
FXUS63 KABR 021949
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
249 PM CDT Thu May 2 2024

.KEY MESSAGES...

- Initial round of rain ending, with more pop up summertime like
showers developing over central SD through 00Z and transitioning to
northeastern SD before ending early this evening. Hazards from these
pop up showers would be lightning and small hail.

- Dry weather expected Friday through the weekend for north central
SD. However, there is a 40-60% chance of rain over south central to
northeastern SD and western MN mainly Friday afternoon through
Friday night.

- A much larger system looks to affect the region on Monday, with
widespread moderate rainfall. The threat for severe weather still
appears low at this time (higher across NE/KS/OK), but we will
continue to monitor trends.

&&

.SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/...
Issued at 249 PM CDT Thu May 2 2024

The 19Z surface map shows the exiting southern low over IA and a
couple of merging lows over northwestern ND and north of Aberdeen to
near Jamestown. The exiting lows will allow showers and weak
thunderstorms to quickly end this evening. Before the drier air
completely moves in, pop up showers in the daytime heating will
continue. Mid level lapse rates of 7-8C/km are moving into central
SD. Winds gusting 25-35mph have been common to our west, in this
area of clearing. High mixing will allow for these winds to continue
east. Fortunately, the better mixing diminishes when the stronger
winds of around 60mph move across north central SD after 00Z. Still,
stronger showers or a couple of thunderstorms will remain possible
through the early evening hours, and could be capable of producing
small hail.

The dry weather will be short lived, as next area of low pressure
shifting across the Central Plains will push a 40 to 60% chance of
light rain across much of the area on Friday. Dry weather will
remain over north central South Dakota. Chances for a wetting rain,
rain of 0.10 inches or more, during the day Friday are less than 10
percent for all but south central South Dakota. The strongest winds
Friday will be closer to the exiting surface low, with gusts north
of Highway 12 of 25 to 30 mph through much of the day. Friday night
will feature exiting rain showers over our eastern to southeastern
counties, with a clearing sky. Temperatures west of the James River
will fall into the lower 30s by daybreak Saturday. The 25-75th
percentiles for temperatures are between 31 and 35F for western
Corson County (where temperatures are expected to be the lowest).

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 249 PM CDT Thu May 2 2024

The long term portion of the forecast begins on Saturday with a
surface high pressure and broad upper level trough over the region.
High temperatures may warm to within a few degrees of average. The
surface high pressure shift eastward on Sunday with increasing
southerly winds across the plain states. The southerly winds will
also bring warmer temps in the area with highs reaching the 60s and
70s for most locations. The NBM is showing wind gusts exceeding 30
knots Sunday afternoon, mainly along and west of Highway 83. Higher
gusts exceeding 45 knots will be possible in Corson and Dewey
Counties. The NBM has a 70-85% chance of winds exceeding 45 knots in
north central SD. However, half km winds off the GFS is lower, and
so is the grand ensemble. Thus, will blend in lower wind gusts
Sunday afternoon.

An upper level trough and associated surface low pressure system
will cross the region on Monday, bringing a 55-80 percent chance of
showers. Low level moisture and increasing instability does move
into the CWA ahead of the frontal boundary with the NBM showing a 20
to 50 percent chance surface CAPE exceeding 500 J/kg. The
probability of seeing 1K J/kg is non-existence over the CWA, and
even for much of SD. Even with the limited instability, excellent
deep layer and low level wind shear may produce some storms to
monitor on Monday.

Beyond Monday, the upper level trough remains near the northern
plains with periods of showers in each forecast period next week.
Temperatures next week will favor near average.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1239 PM CDT Thu May 2 2024

Terminals KABR,KATY,KPIR,KMBG

Varied weather conditions are in place to start the forecast as
the surface trough remains from north central to southeastern SD
and slowly exits est. PIR has moved out of the steady clouds
impacting the rest of the TAF locations to the east. Conditions
range from VFR at PIR/MBG to MVFR to borderline IFR conditions at
ABR/ATY. Look for improving conditions west to east through the
daytime hours, with the potential for VCTS at MBG and to a lesser
extent at ABR.


&&

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

$$

SHORT TERM...KF
LONG TERM...SD
AVIATION...KF