250
FXUS63 KABR 050437 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1137 PM CDT Thu Jul 4 2024

.KEY MESSAGES...

- There is a 20% chance of afternoon daytime heating showers and
  thunderstorms on Friday.

- The active weather pattern of showers and thunderstorms will persist
  into the weekend, mainly focused over eastern SD into west
  central MN with around a 50% chance of showers and thunderstorms
  Saturday afternoon and Sunday afternoon.

&&

.UPDATE...
Issued at 608 PM CDT Thu Jul 4 2024

The forecast remains on track this evening. May need to adjust
hourly pops in a few hours if showers and thunderstorms do not
diminish across central SD.

&&

.SHORT TERM /THIS EVENING THROUGH FRIDAY NIGHT/...
Issued at 249 PM CDT Thu Jul 4 2024

The large closed low system continues to rotate over the region.
Reports and radar rainfall estimates have generally been an inch or
less through early afternoon, however MRMS QPE does suggest a small
area in the southeast Brown/southwest Day/northwest Clark/northeast
Spink county region which may be pushing over 2+ inches in some
spots. We also received one report of water over secondary roads in
northern Clark County. Crest unit streamflow captures this area well
and an areal flood warning has been issued. Any additional
thunderstorm activity will only exacerbate the overland flooding
threat.

Showers and thunderstorms have gradually decreased in areal coverage
as the whole system continues its slow and steady track eastward.
However, isolated showers and thunderstorms remain possible through
the evening. Especially over areas that have scattered cloud cover
and have/will receive some sunshine/daytime heating. The severe
threat remains low, however meso-analysis progs do show steep low
level lapse rates and up to 1000 J/KG of SBCAPE. Enough to get pulse
storms going, maybe even enough for a strong storm to produce some
brief, small hail.

Conditions should dry out overnight. The region will remain in the
northwest flow aloft pattern through Friday. No strong forcing
Friday afternoon, but a few daytime heating showers or thunderstorms
are possible (20-40%). Mostly sunny skies and seasonal temps are
also anticipated. A brief reprieve is expected before another
shortwave moves in late Friday into Saturday.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 249 PM CDT Thu Jul 4 2024

A +PNA pattern continues through the weekend consisting of a highly
amplified ridge and mid level high over the western CONUS and broad
longwave trough over the central CONUS. Within this pattern, several
shortwaves will be swinging in from the northwest, riding the base
of the trough, and then exiting northeast as it follows the flow on
the downwind side of the trough through Sunday. Highs for the
weekend will range in the 70s to around 80, which is 4 to 10 degrees
below normal!

With the northernmost shortwave, ensembles are coming together
better on the placement of the surface low, forecasted to be over
~central/southern Manitoba at 12Z Saturday. A cold front will extend
from this and westward through MT. A shortwave to our south will
feature its surface trough/leeside low forming during the same
time. Ahead of the cold front and to the east of the leeside low,
moisture will be filtering northward with PWAT around 1 inch and
IVT around 200kgm-1/s-1, which is average for this time of year.
Surface dewpoints will be in the 50s to lower 60s across our CWA.
Ensemble mean indicates broad precipitation (30-50% NBM) during
the day. As the cold front tracks more east/southeast and becomes
more defined, (along with daytime heating/instability) pops
increase to 30-65%, highest east of the Mo River for the afternoon
and evening timeframe. Prob of CAPE>1000j/kg is consistent
between the GEFS/EC for early afternoon, ranging from 10-50%,
highest over our eastern and southeastern CWA. However for 00Z, EC
drops to less than 10% and GEFS increases to 30-80%, highest
again in same area. Prob of 2000 J/kG per GEFS is 10-20%. Steeper
lapse rates of 6-7C are also noted. So with moisture, instability
and lift, thunderstorms are possible. Prob of 1000 j/kg and
shear>30kts remain low though, between 10-20%, over central to
east central SD. With this, SPC does highlight a day 3 marginal
risk of severe storms on the northern fringe of this higher
instability.

By Sunday, the front is forecasted to extend from the eastern
Dakotas through central NE as the northern shortwave digs a bit
further southeast across the northern Conus. This will continue to
bring chances of precip ahead of the front as well as post front,
with pops increasing to 30-50% Sunday afternoon, per daytime
heating, with chances diminishing towards sunset as the front and
low continues to track southeast. Weather looks to be mostly quiet
next week as of now with just a slight chance of storms (15-20%)
Monday afternoon over our eastern CWA post low. CPC 6-10 day outlook
from July 9-13th has a 35-45% chance of above average temps.
Probabilities increase for July 11-17 with the incoming ridge (50-
60%).

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1136 PM CDT Thu Jul 4 2024

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail at all sites except KATY through
Friday evening. MVFR stratus is expected to develop near KATY
Friday morning before clearing by afternoon.

&&

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

$$

UPDATE...Wise
SHORT TERM...Serr
LONG TERM...MMM
AVIATION...Wise