Area Forecast Discussion
Issued by NWS Aberdeen, SD

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS63 KABR 201740 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1240 PM CDT SAT AUG 20 2016

.UPDATE...
Issued at 1220 PM CDT SAT AUG 20 2016

See the updated aviation discussion below.

UPDATE Issued at 1018 AM CDT SAT AUG 20 2016

Made a couple of minor adjustments to temperatures today. Overall,
the forecast is on track and no major changes were needed.

&&

.SHORT TERM...(Today through Monday Afternoon)
Issued at 331 AM CDT SAT AUG 20 2016

Upper trough axis is moving eastward across the eastern Dakotas
early this morning. Showers continue to move across the CWA with the
highest concentration over the eastern CWA. The upper trough will
move into MN later this afternoon, with weak instability residing
across eastern SD and west central MN. Mid-level lapse rates begin
to steepen this afternoon with daytime heating and continued cool
temps aloft. Setting the stage for afternoon instability-driven
showers and isolated thundershowers. All CAM solutions agree with
this scenario, just a matter of coverage and how far west to include
POPs for the showers. Did nudge things back west just a tad while
changing wording to coverage and keeping POPs in the 20 to 40 range.

System moves out of the area tonight, with surface high pressure
settling in. This is a cool high pressure system, and if ideal
radiational conditions set up, we`ll be looking at some rather
chilly morning lows come Sunday morning. Lows will drop down into
the 40s, but it`s just a matter of how low in the 40s favored cool
spots will get. Models do hint at some mid-level cloud cover
floating across, so will have to keep an eye on that. If it appears
skies will be mostly clear, we can go ahead and tank the James River
valley for sure where winds will be the lightest. Lower 40s are
probably a good bet in the James Valley under ideal conditions.

Warm air advection pattern returns on Sunday with south to southwest
breezes kicking in. Mid-level temps begin to warm once again and
highs will rebound into the 70s and 80s across the CWA. Much warmer
air moves in on Monday, with highs surging into the 80s and 90s.

.LONG TERM...(Monday Evening through Friday)
Issued at 331 AM CDT SAT AUG 20 2016

An upper ridge will have just passed over the eastern CWA with
southwest flow aloft ahead of the next upper trof. A 50kt low level
jet will set up over much of the forecast area with around 1500 j/kg
MUCAPE, however a very warm elevated mixed layer will already be in
place with 700mb temperatures of +13 to +14C. With the warmest
airmass already overhead, nocturnal elevated convection appears
unlikely. That warm air aloft will also cap that atmosphere as a
surface front slides underneath into the eastern CWA Tuesday PM.
Will maintain SUPERBLEND pops at this point but a downward trend has
been noted and the GFS/ECMWF both have low QPF amounts. It is also
important to note the GFS is also trending towards more of a post
frontal/cold advection showers type scenario. Cold advection will
follow for Wednesday with cooler temperatures through the remainder
of the forecast as a longwave trof remains situated overhead.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1220 PM CDT SAT AUG 20 2016

Scattered to numerous instability showers and the occasional
thunderstorm will continue across northeast SD and west central MN
through this afternoon. CIGS will bounce between MVFR and IFR
until showers clear by 00z. Northwest winds will decrease this
evening, gradually switch to the west late tonight, and then
return from the southwest by Sunday morning.

&&

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

$$

UPDATE...Serr
SHORT TERM...TMT
LONG TERM...Connelly
AVIATION...Serr



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.