708
FXUS63 KABR 011135 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
635 AM CDT Wed May 1 2024

.KEY MESSAGES...

- Another round of showers and rain developing through the day
  from west to east, lasting through most of Thursday. Rain
  totals range from a few tenths to over a half inch.

- Active pattern continues in the extended period, with at least
  three systems affecting the region. The first two (Thursday
  night, Friday night) bringing generally light rainfall and very
  low chances for severe weather. The third one on Monday
  potentially wetter, with better thunderstorm chances.

- Near to below normal temperatures Friday and Saturday, warming to
  above normal Sunday and Monday.

&&

.UPDATE...
Issued at 630 AM CDT Wed May 1 2024

Aviation discussion updated below for the 12Z TAFs.

&&

.SHORT TERM /TODAY THROUGH THURSDAY AFTERNOON/...
Issued at 333 AM CDT Wed May 1 2024

A weak shortwave ridge is in place this morning, however embedded
within southwest flow that becomes more dominant, we see mid level
moisture advect into the region through the course of the day. This
very subtle wave helps develop a low in Wyoming that drifts
northeast, while a stronger low develops to the south tonight.
Moisture associated with both features lingers through Thursday
afternoon. With mainly mid level forcing, not expecting much thunder
with these systems. NBM spread (25th/75th percentiles) in total
moisture ranges from just a few tenths to a half inch. GEFS plumes
is about the same. Should at least get enough sunshine today to
score a high around average at least.

&&

.LONG TERM /THURSDAY EVENING THROUGH TUESDAY/...
Issued at 333 AM CDT Wed May 1 2024

Thursday night we`ll see shortwave energy departing the region, with
lingering rainfall chances (20-40%) across the northern CWA. Very
little instability is noted in the models during the Thursday night
time period. GEFS/GEPS/ENS all showing mean QPF values below 0.10in
as well, so expecting just light shower potential as the shortwave
departs.

Next shortwave moves through Friday night, but is rather progressive
and once again lacks instability. In fact, NBM thunder probabilities
are under 10%. As for precipitation, don`t see many signs pointing
towards heavy rainfall. Even 75th percentile 24-hr precip ending at
18Z Saturday is under 0.50in.

After the aforementioned shortwave departs on Saturday, we actually
get some upper level ridging building in across the Northern Plains
into Sunday. GEFS/GEPS/ENS all showing mean 850mb temps generally
ranging from +11C to +14C by 06Z Monday. This means we`ll see highs
warm rather nicely by Sunday once the upper ridge is overhead.
Current highs feature 70s across the region Sunday and even into
Monday.

Will then be watching for perhaps a stronger low pressure system
moving into the region Monday into Monday night. As expected,
cluster analysis shows there are some differences amongst
GEFS/GEPS/ENS in regards to how deep the trough is, but looks to
potentially be a better rain maker than the two waves mentioned
previously. GEFS/GEPS/ENS also show a bit more instability due to an
extended southerly low-level fetch into the Northern Plains bringing
moisture northward. Although, CAPE means are still all below 1000
J/KG. Grand Ensemble 75th percentile 24-hr precipitation ending at
12Z Tuesday is between 0.50-0.75in. It`s also showing mean PWAT
values around 1 inch across the eastern CWA at 00Z Tuesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 630 AM CDT Wed May 1 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail to start the TAF period, but trend
towards MVFR by the end of the period as yet another storm system
moves into the region. -RA/-SHRA also expected to move into the
area later in the TAF period, although any VSBY reductions are
forecast to remain minor.

&&

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

$$

UPDATE...TMT
SHORT TERM...Connelly
LONG TERM...TMT
AVIATION...TMT