Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 251717

Area Forecast Discussion
National Weather Service Aberdeen SD
1217 PM CDT Fri May 25 2018

Issued at 1205 PM CDT Fri May 25 2018

Only minor adjustments, mainly to raise temperatures a tad in far
northeast South Dakota and western Minnesota. Will keep the chance
for storms in the northeast/western MN thanks to west/northwest
flow aloft, a deep mixed layer already overhead, and ACCAS moving
into that area.


.SHORT TERM...(Today and Tonight)
Issued at 357 AM CDT Fri May 25 2018

Water vapor imagery early this morning shows mid-level energy across
eastern MT and eastern WY moving into the western Dakotas. In fact,
over the past few hours we`ve seen an ACCAS field develop across
western SD, with a few embedded light showers or sprinkles, along
with a brief thundershower or two. Taking a look at CAM solutions, a
few models are picking up on this subtle piece of energy and drift
it across the region this morning. By afternoon, some of the
shortwave energy back to our west will be over the eastern CWA. At
the surface, we still have a weak instability axis over the eastern
CWA with MLCAPE values from around 800 J/KG to 1300 J/KG. Bulk shear
is rather low though. Not much capping in place either, so there
seems to be some justification in the CAM solutions showing of
scattered thunderstorms across the eastern CWA this afternoon.
Inserted POPs to reflect the latest trends. CAM`s may be overdoing
things a bit, but given the energy upstream combining with the weak
instability axis, and decent agreement in the varying solutions,
felt it was necessary to introduce POPs.

The other story today will be the hot temperatures. Rather toasty
temps at 925/850 mb. Raised temps a couple degrees from previous
forecast. Also have a favorable west wind in a slightly drier air
mass compared to previous days which should also help with warming.

.LONG TERM...(Saturday through Thursday)
Issued at 357 AM CDT Fri May 25 2018

The long term period will be an active time period with several
rounds of thunderstorms affecting the region. Saturday looks to be
on the only dry day across the cwa as an upper level high pressure
ridge slides over the region along with its accompanying surface
ridge. Therefore, expect sunny and hot conditions again. Then the
weather pattern becomes active as a large upper level low pressure
area over the southwest U.S. begins to send off short wave troughs
into our region. This will continue until the upper low pressure
area weakens as it lifts northeast and across our region through
Wednesday. These short waves along with an almost continuous llj
bringing in moisture and instability through this period will bring
several rounds of thunderstorms from Saturday night into Wednesday.
At this time, Wednesday night and Thursday look to be dry with maybe
some return flow already showing up out again out west Thursday
afternoon. Temperatures will be much above normal through the entire
long term with Saturday and Sunday looking to be the warmest in the
90s. Monday through Thursday should be mostly in the 80s and lower


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1205 PM CDT Fri May 25 2018

VFR conditions for all terminals. Cant rule out a storm near
KATY this afternoon.




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