Area Forecast Discussion
Issued by NWS Aberdeen, SD
FXUS63 KABR 201511 AAB
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1011 AM CDT FRI MAY 20 2016
Issued at 1009 AM CDT FRI MAY 20 2016
A few light showers have developed across the northwestern part of
the CWA this morning. Broad area of cloud cover moving out of
Nebraska should enshroud the central and eastern CWA by this
afternoon. No changes to winds or temperatures at this time.
.SHORT TERM...(Today through Sunday Afternoon)
Issued at 356 AM CDT FRI MAY 20 2016
The flow pattern across the CWA changes very little over the
course of the short term, until the afternoon hours Sunday.
This morning, seeing thundershowers on the nose of a 30-40kt low
level jet although MUCAPE values are only on the order of a few
j/kg. Profiles for the rest of the day support mainly stable
conditions aloft with some shallow cumulus formation. Left in
mention of sprinkles from previous shift but cloud depth will only
extend between the 5 and 8kft level and is probably not deep enough
to generate precipitation.
Saturday morning we could see another round of weak storms form as
the low level jet redevelops over mainly the same region. Again
MUCAPE values are only 100-200 j/kg. As the upper trof continues to
move closer to the region Sunday AM, the low level jet increases
with 850mb winds upwards of 50kts. MUCAPE values increase after 06Z
to 500 to 1300 j/kg as the influx of Gulf moisture brings 850mb
dewpoints to +10 to +13C. Surface dewpoints increase into the upper
50s ahead of a surface front, so the focus will shift towards the
potential for severe storms. The best upper forcing will remain to
the west as the upper low drifts into southern Alberta/Saskatchewan,
with best jet dynamics remaining to the west. 700mb temperatures top
out at 2 standard deviations above climo, around 9C. MLCAPE is also
confined to a narrow ribbon along the front, but will top out around
2000 j/kg. Expect the pre-frontal area to remain capped, with
convection developing along the north/south oriented front in the
vicinity of the missouri valley. 0-6kt shear is strongest west river
and drops precipitously to the east, so storms may initially show
organization before moving into a less favorable shear environment.
.LONG TERM...(Sunday Evening through Thursday)
Issued at 356 AM CDT FRI MAY 20 2016
The models show very good agreement in the long term with the upper
level flow pattern across the region. Large upper level troughing
will be situated over the western U.S. through the entire period.
This will put our region in southwest flow aloft with several short
wave troughs coming over our region. The first significant short
wave trough and its surface cold front will move/sweep across the
region Sunday night. There will be decent instability along with
good deep layer shear and lift with the short wave and surface front.
Therefore...have good chances of showers and storms in for Sunday
night. Some of these could be severe. There will likely be a little
break in the action Monday and Monday night with chances of
showers/storms coming back for the rest of the week. Highs through
the week look like they will be mostly in the 70s to around 80
degrees across the area.
.AVIATION...(For the 12Z TAFS through 12Z Saturday Morning)
Issued at 703 AM CDT FRI MAY 20 2016
Mainly vfr conditions are expected at all locations through today
and tonight. Stratus clouds to south of the region this morning will
move north and mix out to a higher level through the day. PIR could
have a temporary mvfr ceiling this morning. Otherwise...expect sct-
bkn low vfr clouds at all locations today. Some lower mvfr ceilings
are expected to move in later on tonight. Southeast winds are also
expected to be breezy/windy today at all locations in the 15 to 30
knot range...falling off this evening.