948 
FXUS63 KABR 131804 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
104 PM CDT Mon Sep 13 2021

.UPDATE...
Issued at 1254 PM CDT Mon Sep 13 2021

See the aviation discussion below for the 18Z TAFS.

UPDATE Issued at 1047 AM CDT Mon Sep 13 2021

Tracking showers and scattered thunderstorms this morning as they
progress from west to east across central SD into northeast SD.
This activity will continue pushing eastward through the 
rest of the morning into the afternoon and early evening hours as
low pressure and associated frontal boundaries move across the 
state. Some storms will remain capable of being strong to severe. 
This threat looks to shift out of central SD this morning into 
portions of east-central and southeast SD later this afternoon 
where the better instability and deep layer shear will reside. 
Hail will be the primary threat with the addition of strong winds
associated with the afternoon activity. Made some minor 
adjustments to the forecast to account for radar and pcpn trends, 
otherwise it remains on track through the remainder of today.

UPDATE Issued at 626 AM CDT Mon Sep 13 2021

See updated aviation discussion below.

&&

.SHORT TERM...(Today through Tuesday Afternoon)
Issued at 317 AM CDT Mon Sep 13 2021

Warm air advection has developed this morning ahead of a low 
pressure system, broad upper level trough. Surface dew points are 
slowly increasing west of the Missouri River with readings in the 
low to mid 50s. A low level jet over the western Dakotas should 
help maintain the ongoing convection over Wyoming. Increasing 
instability along and west of the Missouri River, along with good 
deep layer shear could support a few strong to severe elevated 
storms through the mid morning hours. Instability quickly wanes 
before noon, with general showers and thunderstorms expected. 
Also, as the convection moves eastward, it will encounter a more 
stable environment, with mostly showers, with a few embedded 
thunderstorms expected. There is still the potential of additional
convection over south central South Dakota later this afternoon 
as instability tries to return with some clearing. Later shifts 
may need to monitor the clearing line this afternoon for this 
additional severe threat area. An area of high pressure will 
slowly slide southeastward into the CWA later tonight into the 
morning hours on Tuesday. This may help set the stage for low 
clouds, or fog over a good portion of the CWA, especially over the
higher terrain areas of the Sisseton Hills. The HREF does support
a good area of low cloud cover. A short wave will track southeast
across southwestern South Dakota late tonight and into the 
morning hours on Tuesday. This system could bring showers to the 
far southwestern CWA, or Jone County. Will keep the time period 
dry for now.

.LONG TERM...(Tuesday Evening through Sunday)
Issued at 317 AM CDT Mon Sep 13 2021

The region will be under the influence of surface high pressure at 
the beginning of the extended period. The high begins to get pushed 
east late Tuesday night as a low pressure trough approaches from the 
west. The trough appears to stall out over the western Dakotas on 
Wednesday, with a decent pressure gradient developing, which may 
result in Wednesday being a somewhat windy day. The trough finally 
begins to slide east Wednesday night, with the associated frontal 
boundary tracking from west to east across the CWA late Wednesday 
night into Thursday morning. The front looks to move through dry for 
the most part, but may interact with a bit more moisture across the 
far eastern CWA, so could be a few showers or thunderstorms Thursday 
night into the day Friday. Some of the models are hinting at another 
frontal boundary sometime over the weekend, but most of the models 
bring this through dry, so will follow suit with the forecast for 
now. 

The majority of the extended period will feature high temperatures 
in the 70s and 80s. The exception will be Friday, with cooler highs 
in the mid 60s to mid 70s. Overnight lows will generally be in the 
upper 40s to the 50s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1254 PM CDT Mon Sep 13 2021

Terminals KABR,KATY,KPIR,KMBG

VFR cigs initially this afternoon will become MVFR to IFR at 
times underneath showers and scattered thunderstorms. These 
conditions will especially be realized at KABR and KATY through
late this afternoon/early evening. MVFR vsbys will also be 
possible in the heavier pcpn. The showers and storms will come to 
an end from west to east late this afternoon into this evening and
should be clear of all terminals by 03Z tonight. Low clouds and 
some fog development is expected through early Tuesday morning. 
MVFR/IFR cigs along with perhaps some MVFR vsbys will be possible
at all TAF sites overnight. Improving conditions are expected by 
the end of this valid time period.

&&

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

$$

UPDATE...Vipond
SHORT TERM...SD 
LONG TERM...Parkin 
AVIATION...Vipond