Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 162030
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
330 PM CDT Sat Sep 16 2017

.SHORT TERM...(This Evening through Sunday)
Issued at 328 PM CDT Sat Sep 16 2017

Most precipitation has cleared the area though thick coverage
of closed cell cumulus remains in place. Not a clear case where
stratocumulus has developed in cold air due to daytime heating so am
suspect that a vast majority of guidance rapidly clears the skies
this evening/early overnight. That said, there is fairly
overwhelming evidence in guidance that this will occur. So with
clear skies, high pressure moves across western into central South
Dakota overnight. This gives most of our area a west wind. We also
have quite high dewpoints, with values in the 40s across the CWA. At
the same time, our temperatures have struggled to reach mid 50s.
Thus - have no problem mentioning frost in the forecast, along with
frost headlines.

I will also note that there is an area of mid-cloud in central
Nebraska, headed northeast towards the CWA. Uncertain at this time
if thise area of clouds will be overhead or departing this evening
or if it will interfear with the frost forecast. At this point, is
looks like it will be east of the more likely areas for frost.

Sunday will see good mixing conditions in a cold airmass with a west
breeze, becoming southerly as the high continues southeast.

.LONG TERM...(Sunday Night through Saturday)
Issued at 328 PM CDT Sat Sep 16 2017

The main focus in the long term will be the frontal passage Tuesday
night and the associated chances for showers and thunderstorms.
Before that, not much in the way of weather to talk about. High
pressure will push east of the area Monday allowing a warmer and
more moist airmass to return. As a weak mid level wave passes early
Monday, a few showers will be possible.

On Tuesday, a strong surface gradient develops ahead of an
approaching low pressure system and cold front. Stronger southerly
winds, warmer temps and a more humid airmass will settle into the
region by Tuesday evening. Models are in somewhat better agreement
on timing of the FROPA Tuesday evening into Tuesday night. At this
point, the potential is there for seeing some strong to possibly
severe thunderstorms with this weather system. Still too early to
talk specifics, but the picture should get clearer the next couple
days on this potential.

The remainder of the long term portion of the forecast will continue
to feature an active pattern as an upper trough develops across the
western CONUS. Shortwave energy will kick out of the deep western
trough from time to time and provide our area with periodic chances
for precip late in the work week into next weekend. Temperatures
through the period will remain seasonal with readings at or above
normal.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1212 PM CDT Sat Sep 16 2017

MVFR low stratocumulus covers most terminals through the
afternoon/evening. Guidance does have this dissipating/moving
north so TAFs will trend towards VFR with a west to northwest wind
component through mid-day Sunday.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Frost Advisory from midnight tonight to 8 AM MDT Sunday for
     SDZ003-015.

MN...None.
&&

$$

SHORT TERM...Connelly
LONG TERM...Vipond
AVIATION...Connelly



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