Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 312315 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
615 PM CDT WED AUG 31 2016

.UPDATE...
Issued at 614 PM CDT WED AUG 31 2016

See below for an updated aviation forecast discussion.

&&

.SHORT TERM...(This Evening through Friday Night)
Issued at 317 PM CDT WED AUG 31 2016

Isentropic forcing responsible for elevated convection has shifted
somewhat and become less enhanced, however light rainfall still
being observed upstream with a steering flow that will take showers
to about the state line. Farther south and west, ample daytime
heating and NAM profiles showing marginal instability, along with a
surface boundary and modified air support at least a slight chance
for storms. Nothing severe thanks to less than 1000 j/kg skinny cape
and weak steering flow.

Area of isentropic forcing will shift into the eastern Dakotas
overnight. CAM solutions are spotty with the QPF, and MUCAPE values
drop to only 100-200j/kg. Thus, have introduced just a small area of
slight chance showers for northeast counties.

Focus shifts back west river for Thursday. A pocket of low 850mb
dewpoints will wrap around the high into western counties. At only
around 3-5C, mixing will generate surface dewpoints down into the
low/mid 40s, with min RH values around 20 percent. Mixed winds are
also into the low 30KTS range, suggesting we could see a few spots
hit Red Flag criteria Thursday afternoon. Will let the night shift
re-evaluate as the RH values are marginal.

A 40kt low level jet develops overhead Thursday night, which will
draw more humid air into the western forecast area, however the
corridor of dry air shifts into the eastern CWA. This area is still
green so dewpoints will not collapse as readily compared to those
on Thursday. Mixed winds are a bit higher as well, around 35KTS.

.LONG TERM...(Saturday through Wednesday)
Issued at 317 PM CDT WED AUG 31 2016

The region will be between an upper level ridge to the east and a
trough to the west through much of the extended period. A series of
shortwaves will ride up in the southwest flow and across the area,
especially later in the period.

A surface frontal boundary will remain nearly stationary over the
western part of the state on Saturday, then begins to push eastward
and across the CWA Saturday night and Sunday. Low pressure then
strengthens over Colorado, and eventually swings another frontal
boundary across the area early next week. Both of these fronts will
be the focus for shower and thunderstorm activity, so will stick
with fairly high pops Sunday through the day Monday. Models then
begin to differ on additional precipitation chances, with the ECMWF
a bit drier than the GFS. For now, with stick with Superblend`s
slight chance to chance pops Monday through Wednesday.

Saturday will be the warmest day of the period with highs mainly in
the 80s. Cooler air then moves in with highs in the 70s the
remainder of the period. Overnight lows will be in the 60s Saturday
night, then lows in the 50s will be common.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 614 PM CDT WED AUG 31 2016

VFR conditions will prevail across the area through Thursday.

&&

.ABR Watches/Warnings/Advisories...
SD...NONE.
MN...NONE.
&&

$$

UPDATE...Dorn
SHORT TERM...Connelly
LONG TERM...Parkin
AVIATION...Dorn



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