Mobridge, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

884
FXUS63 KABR 141841
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
141 PM CDT Wed May 14 2025

.KEY MESSAGES...

- Showers and thunderstorms are expected this afternoon through Thursday
  morning (60-95% chance). A few storms could become severe with
  large hail, 1"+ in diameter, and wind gusts of 60-70 mph being
  the main threats.

- A 60-90% chance for showers and thunderstorms persist Thursday
  night through Friday night with a 50% chance or greater of
  seeing at least an additional half inch or more of rainfall.

- Cannot rule out severe storms over eastern South Dakota and
  western Minnesota on Thursday, mainly between noon and 4 pm.
  All hazards will be possible.

- The probability of low temperatures falling to 36F degrees or colder
  Saturday night is 45 to 70 percent in areas along and north of
  the US Highway 212 corridor.

&&

.SHORT TERM /THIS EVENING THROUGH THURSDAY MORNING/...
Issued at 138 PM CDT Wed May 14 2025

The main concern through tonight will be the potential for severe
thunderstorms over portions of central and northeastern SD into west
central MN. Synoptic setup consist of south to southwesterly flow
continuing over the Northern Plains on the PVA side of a longwave
trough off to our west, with several shortwave pulses moving from
southwest to northeast over the CWA this evening and tonight. A 60-
70kt jet streak at the base of the trough will help deepen the
trough and make it become more negatively tilted overnight into
Thursday morning, with a mid level low forming over southern SD by
12Z. With this setup aloft, a large area of low pressure exists over
the Central and Northern Plains with the main low to our south
sitting over KS/NE by 00Z. North of this low, an ongoing inverted
trough sits over the CWA with very slow moving to stationary front
positioned through central SD by 00Z. Through the overnight, this
front will slowly track east and the low to our south will swing
northeast, with the center over ~southeastern SD by 12Z Thursday.

Dewpoints will continue to range in the 50s, with mid to upper 50s
to lower 60s over central SD this afternoon and evening along and
ahead of the front per southerly flow bringing in the moisture.
These higher value will spread eastward over the CWA tonight and
mainly over the eastern CWA early Thursday morning with dewpoints
dropping into the 40s behind the front over central SD. HREF/RAP
indicates there will be some instability to work with with MU/ML
CAPE up to 1000-1500 J/KG over central SD this afternoon, mainly
along an ahead of the front, with values decreasing to under 1000
J/KG by 00Z and decreasing even more around and after sunset. Shear
does not really coincide with the instability as it increases to
around 30-40kts behind the front over central SD and shifting
eastward overnight.

This leads to storm initiation as HRRR/HREF indicates isolated to
multicellular clusters firing up along and west of the MO River
between ~18-22z. HREF`s 1hr max UH>75m2s2 indicates a chance (30%)
of a few of these cells having more organized convection and prob of
UH>150m2s2 is 10%, meaning right moving supercells along and behind
the front. There could be a couple of hours of possible overlap
between the higher values of CAPE and shear during this time. The
threat during this period would be large hail (quarter to inch an a
half, especially supercells) and 60 mph wind gusts. HREF prob of
hail/wind is about 2% over south central SD this evening with the
northern edge of the 5-15% over Jones/Buffalo Counties as the bulk
of these higher chances are over southern through southeastern SD
into NE. Comparing this to SPC, probabilities are a bit higher and
extend further north and east over the CWA. These UH cells will
weaken with the evening over the northern portion of the state when
convection turns to more of a linear setup, from south central SD an
southward) pushing eastward, with a possible bowing segment
indicated by HRRR, as shear is parallel the the front. The strongest
of this line looks to stay south/southeast of our CWA where there is
better instability, however, there is still the potential for severe
wind gusts on the leading edge of the system with gusts of 60-70
over south central SD to start and over portions of the eastern to
southeastern CWA through the overnight as the line shifts more
northeast into MN.

&&

.LONG TERM /THURSDAY MORNING THROUGH WEDNESDAY/...
Issued at 138 PM CDT Wed May 14 2025

A powerful low pressure system early in the forecast period will be
the main forecast challenge.

The period begins with about a 990 mb surface low pressure over the
eastern Dakotas, with cold air advection over the western Dakotas.
The surface low does strengthen to around 984 mb over eastern ND,
and perhaps northeastern SD. A 984 mb pressure is near record
territory for May, and reason why it`s outside the climate normal on
the NAEFS return interval. The record May low pressure occurred in
1950 and produced highs in the 30s and low 40s, along with
accumulating snowfall. Thankfully, forecast low level temperatures
will be warm enough to support all liquid event. 925 mb temps in the
single digits on Thursday are below the 25th percentile for this
time of year. High temperatures along and east of the James Valley
may begin the day in the mid 60s, with perhaps cooling temperature
during the mid and late afternoon hours. West of the James should
see highs in the 50s. With the deep low pressure system, strong
northwesterly winds can be expected across the western half of the
CWA on Thursday. The probability of seeing wind gusts exceed 50 mph
is 15 to 40 percent, with a higher chance over the far western parts
of the CWA. Overall, winds on Thursday favor advisory levels, with
low end (<35%) potential for high wind warning criteria being met.
Will issue a high wind watch for the favored windy area in south
central SD, and a wind advisory for other locations.

Attention turns toward the potential for low topped supercells over
the eastern CWA on Thursday. Various hi-res models suggest one band
of showers and storms moving northward across the eastern CWA during
the morning hours, with a break sometime around 14-17Z. Another line
of storms may move northward across eastern SD after 17Z, with ample
low level moisture possible behind a warm front. The surface low
associated with the warm front does appear to retrograde back to the
northwest some with a cold front surging eastward across the CWA. A
potential triple point area over northeastern SD may lead to the
development of low topped supercells with tornadoes possible. The
Day 2 outlook from SPC does highlight the potential for supercells,
with all threats possible.

The storm system meanders across the northern plains Thursday night
through at least Friday, with deformation zone showers and storms
remaining over the forecast area. The rainfall associated with this
storm system is much needed, and should provides some relief for
farmers. After a mostly dry period Saturday into Sunday, another
storm system will bring widespread rainfall across the forecast
area. The 24 hour probability of a half inch of rainfall by 12Z
Tuesday is 60-75% over the entire CWA. Temperatures throughout the
period will favor below average. Low temperatures are forecast to
drop into the 30s on Saturday and Sunday morning, and later first
shifts may need to add frost into the forecast.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1215 PM CDT Wed May 14 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail through the afternoon and tonight. A
slow moving cold front shifting west to east will produce a line
of SHRA/TSRA across central SD this afternoon and evening, likely
affecting KPIR/KMBG at some point. Vsby and cigs may drop into
MVFR/IFR in heavier showers. Strong to severe storms are possible,
with hail and gusty surface winds around 50 knots or higher. At
this point, this activity doesn`t look to reach the KABR/KATY
terminals until after sunset or closer to midnight.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 10 AM CDT /9 AM MDT/ Thursday to 1 AM CDT
     /midnight MDT/ Friday for SDZ003-004-009-015>017-034>037-
     051.

     High Wind Watch from Thursday morning through Thursday evening
     for SDZ033-045-048.

MN...None.
&&

$$

SHORT TERM...MMM
LONG TERM...SD
AVIATION...MMM