966
FXUS63 KABR 010158 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
858 PM CDT Tue Apr 30 2024

.KEY MESSAGES...

- At least 3 or 4 notable wave will move through the region,
  providing rainfall chances. Thunderstorm chances (including
  potential for severe storms) overall, look rather low through the
  period.

- Near to below normal temperatures early in the period potentially
  warming to near or above normal beginning Sunday into early next
  week.

&&

.UPDATE...
Issued at 847 PM CDT Tue Apr 30 2024

Convection has shifted northeast out of the CWA, along with the
surface low and attendant cold front. So, while the surface high
out west starts to build in, the pressure gradient in place will
help to keep some west-northwest 10 to 25 mph winds, with
occasional higher gusts, going well into the overnight.
Eventually, winds will settle down to around 10 mph or less, all
the while the clearing sky should remain clear/mostly clear
through sunrise Wednesday. Seems like the lower low temps (~31 to
39F) out west/northwest in the CWA and the higher low temps (~36
to 43F) in and east of the James River valley should suffice.

UPDATE Issued at 614 PM CDT Tue Apr 30 2024

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.SHORT TERM /THIS EVENING THROUGH WEDNESDAY NIGHT/...
Issued at 331 PM CDT Tue Apr 30 2024

At mid-afternoon, sfc low pressure and an associated cold front are
tracking their way eastward across eastern South Dakota. Showers and
thunderstorms have developed and advanced in a northeast fashion in
conjunction with this system. A robust, negatively tilted s/w trough
is currently shifting northeast across our region with strong
southwesterly flow aloft of about 45-55 kts helping to kick off the
convection observed across eastern SD this afternoon. Ingredients
for severe weather is just lacking for the most part in our CWA
compared to locales farther south of our forecast area. BUFKIT
profiles at Watertown continue to indicate steepening mid level
lapse rates prior to the fropa with some skinny CAPE developing late
this afternoon. Our southeast zones remain on the northern fringe of
the plume of instability. MUCAPE values off the HREF top our around
500j/kg late this afternoon across our far southeast zones before
shifting east out of our area by 00Z. SPC continues to highlight
portions of Deuel and Hamlin Counties for a marginal risk for severe
weather the remainder of today. Mid/upper lvl clouds are quickly
shifting off toward the northeast exposing the lower agitated CU
across our eastern zones, so we are expecting some heating to take
place still with the help of a little sunshine. CAMS do continue to
initiate surface based convection in our eastern forecast zones this
afternoon before it moves into western Minnesota. So, still can`t
rule out a strong or two in our far southeast that may produce some
hail and a localized strong wind gust or two.

For the most part, the convection is all over and done with by early
this evening. Increasing west to northwest winds on the backside of
this disturbance will continue to gust on the order of about 25-
40mph into tonight before beginning to relax by late evening. Wind
prone areas of the Sisseton Hills will hold onto the stronger winds
until after midnight. High pressure briefly moves through the area
during the first half of Wednesday. By the afternoon, it`s already
east of the CWA and we begin to pick up southerly low-lvl flow once
again. A persistent mid-level low poised northwest of our region
will maintain southwest flow aloft over our area. Mid level warm
advection kicks in once again by Wednesday afternoon helping to kick
off more shower development across NE and lifting north into central
and northeast SD Wednesday afternoon and Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 331 PM CDT Tue Apr 30 2024

The long term portion of the forecast begins on Thursday with an
area of low pressure and upper level trough crossing the region,
bringing yet another around of showers. According to the grand
ensemble, the probability of seeing a quarter of an inch of QPF is
35 to 55 percent. As of now, some of the deterministic models are
indicating a possible dry period on Friday, before more showers
cross the central and southern northern plains Friday night. The
latest NBM is also trending drier on Friday.

Ridging aloft begins to build across the area for the weekend,
bringing a period of dry and warmer conditions. High temperatures in
the 70s may finally return to the forecast area by Sunday.
Unfortunately, increasing southerly winds are also expected with the
NBM showing a 40 to 90 percent chance of gusts exceeding 30 mph
Sunday afternoon. Beyond Sunday, there are some differences among
models with the timing and evolution of the next upper level trough
and associated surface low pressure system. Some models suggest
showers will move back into the area as soon as Sunday night, while
others suggest Monday through Monday night. The NBM has high pops,
30 to 40 percent Monday into Tuesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 614 PM CDT Tue Apr 30 2024

Terminals KABR,KATY,KPIR,KMBG

Showers and thunderstorms have redeveloped late this afternoon
over northeast South Dakota, moving northeast. Lower (sub-VFR)
cigs will continue to be possible for the first couple of hours at
KABR. Otherwise, look for VFR conditions to prevail over the next
24 hours. Northwest winds between 20-30 kts with some higher gusts
will be possible through 06Z, mainly at KPIR and KMBG before winds
relax.

&&

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

$$

UPDATE...Dorn
SHORT TERM...Vipond
LONG TERM...SD
AVIATION...Dorn