313
FXUS63 KABR 201306 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
806 AM CDT Mon Apr 20 2026

.KEY MESSAGES...

- Red Flag Warning has been issued for east central and far
  northeastern South Dakota as well as west central Minnesota
  due to gusty winds (up to 30-40 mph) and low relative humidity
  values. Fire weather concerns continue Wednesday as well.

- Rain chances return Wednesday night into Thursday, with a 40-75%
  chance along and after a cold front moves through.

- Strong sustained west-northwest winds 25 to 40 mph with gusts up
  to 50 mph are expected on Thursday.

&&

.UPDATE...
Issued at 757 AM CDT Mon Apr 20 2026

No changes planned, at this time, to the today period forecast.
Red Flag Warning remains in effect today across the far eastern
forecast zones. Still expecting that overlap in frequent
sustained winds or gusts of 25 mph and relative humidity less
than 25 percent from early afternoon through early evening
across the far eastern forecast zones. Relative humidity values
likely tank to 15 percent or less across the southwestern zones
(south of a line from Ridgeview to Vayland), but by the time
that is happening, winds are expected to really die off to less
than 15 mph and perhaps even become a bit variable in direction
as a lee-of-the Rockies/pseudo warm front is progged to be
working into the west river zones of the CWA from ~2pm cdt to
~8pm cdt. After 7pm cdt, a cold front up in North Dakota will be
pushing down across the CWA, reaching the I-90 corridor later
tonight after 06Z. Currently south-southwesterly mixing layer
winds are supporting a period of low level WAA today that should
be pushing the mercury up into the 60s and 70s throughout the
CWA. Can`t rule out some areas in central/south central South
Dakota seeing 80s today given all the dry air and sunshine that
will be around.

UPDATE Issued at 624 AM CDT Mon Apr 20 2026

Aviation discussion updated below for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 208 AM CDT Mon Apr 20 2026

A high pressure is moving east out of eastern SD this morning as
another area of surface high pressure starts to develop in Canada.
The south/southwesterly winds between these two highs will pick up
early this morning over central SD and move east during the morning
over north central SD and west central MN. These winds are forecast
to gust up to 30-40mph. The winds taper off over central SD before
noon and decrease during the afternoon over northeastern SD.

The southerly/southwesterly winds will be bringing warm, dry air
into the area, which will lead to increased fire weather concerns
today. Minimum relative humidity values are forecast to get below
25% over most of central and northeastern SD, with south central SD
seeing values below 20%. A Red Flag Warning has been issued for
parts of east central and far northeastern SD and west central MN as
the lower RH values and stronger winds are forecast to overlap. If a
fire were to ignite in these areas, it could become difficult to
control or suppress. While areas to the west will see the lower RH
values, these values will occur after the stronger winds move
through. While these areas west of the James River will not meet Red
Flag Warning criteria, there will still be some fire weather
concerns due to the lower RH values.

Temperatures will warm today and Tuesday to be 10-20 degrees warmer
than normal, into the mid 60s to low 80s, with the warmest
temperatures over south central SD. The continuous warm air moving
into central and northeastern SD will add up though the beginning of
the week and cause temperatures to be 25-30 degrees warmer than
normal Wednesday, getting up into the 90s for some areas. The dry
air and occasional high pressure moving over the state will help to
keep precipitation out of SD and mostly sunny skies around through
the middle of the week. Wednesday continues to show some signs for
fire weather concerns due to the warm and dry conditions and
stronger winds (gusts of 30-40 mph) forecasted during the afternoon.

A surface low pressure starts developing to the northwest Tuesday
night into Wednesday. This low and a cold front attached to it look
to move east Wednesday night into Thursday. Rain is forecast to
develop along the front as it passes through the area Wednesday
night through Thursday (40-75 percent chance), with a chance for
some thunderstorm development as well. The front will push cold air
into central and northeastern SD, dropping temperatures below normal
during the end of the work week into the weekend. This CAA will help
the stronger winds aloft get down to the surface Wednesday afternoon
through Friday, with the strongest winds forecast to occur Thursday.
There is a 30-70% chance for winds to gust over 45 mph (wind
advisory criteria) Thursday afternoon, with the highest chances over
areas west of the Missouri River.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 624 AM CDT Mon Apr 20 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Low-level
wind shear (LLWS) is still expected across central SD through
about 15Z and have included mention of this in the TAFs for
KMBG/KPIR.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning from 11 AM this morning to 8 PM CDT this
     evening for SDZ008-019>023.
MN...Red Flag Warning from 11 AM this morning to 8 PM CDT this
     evening for MNZ039-046.

&&

$$

UPDATE...10
DISCUSSION...12
AVIATION...TMT