480
FXUS63 KABR 051739 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1239 PM CDT Fri Jul 5 2024

.KEY MESSAGES...

- There is a 30% chance of afternoon and evening, daytime heat
driven, showers and thunderstorms today.

- The pattern of mainly afternoon and early evening showers and
thunderstorms will continue through the weekend, mainly focused over
eastern South Dakota into west central Minnesota where there is
around a 60% chance of showers and thunderstorms each afternoon.

- Expect a gradual warming trend across the region through next
week. By the end of the week we should be seeing temperatures above
average (5-10 degrees).

&&

.UPDATE...
Issued at 1233 PM CDT Fri Jul 5 2024

See the updated aviation discussion below.

UPDATE Issued at 1046 AM CDT Fri Jul 5 2024

The only forecast change this morning was to push POPs off until
21Z and after. With no significant synoptic forcing, showers and
thunderstorms will be dependent on daytime heating. Hi-res models
concur and don`t show any convection until later this afternoon.
Other forecast fields look to be on track.

&&

.SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...
Issued at 305 AM CDT Fri Jul 5 2024

The morning surface weather map showed our exiting area of low
pressure over southern WI and a large ridge of high pressure across
MT and WY. At 500mb the main low was over southern MN with a broad
trough set up across the Plains States through the New England
states. While brief ridge to northwesterly flow will slide overhead
in the afternoon and evening, embedded waves will remain with
another trough set up along the MT/ND/WY border by 06Z Saturday.

The result will be diurnally driven showers and thunderstorms
drifting southeast. CAPE values will jump to around 1000 J/kg this
afternoon and evening, lowest over south central SD. While the main
focus will be near and east of a line from Aberdeen to Redfield,
along with western Corson County, any location could experience a
shower or brief thunderstorm this afternoon into the early evening
hours. The low chances of precipitation will continue overnight
across central SD and expands to the rest of the forecast area
during the day Saturday, as the 500mb trough moves overhead. Again,
CAPE values will top out near or slightly above 1000 J/kg, highest
over southern SD and to our south (NE) where higher shear values and
lapse rates exist. There is a SPC Marginal Risk (level 1 of 5) of
severe weather over our far southwestern counties mainly Saturday
afternoon.

&&

.LONG TERM /SATURDAY EVENING THROUGH THURSDAY/...
Issued at 305 AM CDT Fri Jul 5 2024

The general trend in the upper level pattern through the end of next
week features a semi-persistent trough across the region, with weak
embedded waves. We see one of these weak upper level waves overhead
for Saturday evening/overnight across the eastern CWA, a second
coming across Sunday and two more Monday night and Tuesday evening,
maybe even another later Thursday. With generally weak low level
flow, and ample ET/low level humidity, BUFKIT profiles in both the
GFS/NAM support a weakly unstable atmosphere with skinny CAPE and
weak shear, for mainly diabatically driven showers and weak
thunderstorms through at least Monday. We do see evidence for the
warm airmass inundating the west to gradually shift east, with
warmer air aloft gradually migrating east into the northern Rockies
for the latter half of the work week, and potentially reaching the
CWA by Friday. As such, for temperatures, anticipate a slow steady
warming trend, with fairly good signal for the warming trend in the
NBM 25th/75th highs/lows...though by Day 7 the NBM highs/lows are
only just then getting to about 5-10F above average.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1233 PM CDT Fri Jul 5 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail. The only aviation concern will be
daytime heating showers and thunderstorms this afternoon. Any
storm that does develop will be isolated in nature making timing
and location difficult to forecast. TAFs will be amended as
necessary.

&&

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

$$

UPDATE...Serr
SHORT TERM...KF
LONG TERM...Connelly
AVIATION...Serr