Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 242353 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
653 PM CDT Mon Jul 24 2017

.UPDATE...
Issued at 653 PM CDT Mon Jul 24 2017

00z aviation discussion updated below.

&&

.SHORT TERM...(This Evening through Tuesday)
Issued at 311 PM CDT Mon Jul 24 2017

MCV continues to track across the forecast area with light showers
and a couple rumbles of thunder. Clouds and rain ahead of this
feature has suppressed temperatures despite warm advection, however
in its wake we can see rapid warming, and a moistening boundary
layer could produce a boundary or two which will provide the focus
for additional convection later today. MLCAPE ranges from 500 to
1500 j/kg and 0-6km shear about 30-40kts, with mostly directional
turning and little speed shear. If any storms develop that are
rooted in the boundary layer, there will be a deep dry subcloud
layer with 1500j/kg DCAPE and freezing levels around 13.5-14kft - so
while there will be some storm structure, the main threat would be
gusty winds.

Convection with the MCV heads east, while anything surface based
will lose support after sunset and dissipate. A 40-50kt low level
jet develop overnight nosing into the Aberdeen/Watertown areas
before migrating east into Minnesota. Meanwhile, a surface front
will move into northwest counties. This is mainly a wind shift and
dewpoint discontinuity.

The front continues south on Tuesday setting up along the southern
periphery of the CWA west of the James valley before curving
northeast into eastern counties. This will be the focus for
additional convection during the afternoon, with best CAPE values
still just over the border in western Minnesota.

Temperatures and humidity will be higher along and south of the
front, with favorable mixing conditions while on the backside,
northeast winds and drier air will keep temperatures closer to
average though we don`t see any real cold advection during the
period.

.LONG TERM...(Tuesday Night through Monday)
Issued at 311 PM CDT Mon Jul 24 2017

Wednesday morning:  With ample moisture, as shown by 65-73 degree 30
mb mean dewpoints, very high instability, and strong shear,
thunderstorms are likely very early Wednesday morning along a
boundary from central South Dakota to the northeast corner of the
state.

Wednesday afternoon through Friday: Increasing high pressure and
a strong ridge build into the region. Dry conditions with highs in
the low to upper 80s will result, with the warmest temperatures
being further west.

Saturday through Monday:  High pressure continues to sit over the
region with temperatures reaching about average highs of the mid 80s
east to low 90s west.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 653 PM CDT Mon Jul 24 2017

VFR conditions are expected at all locations through tonight and
Tuesday. A cool front sliding south across the region late tonight
and Tuesday will bring some thunderstorms on Tuesday. These may
affect the stations at or in the vicinity with the best chances at
ATY and PIR.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 8 PM CDT /7 PM MDT/ this evening for SDZ033-
     045-048.

MN...None.
&&

$$

UPDATE...Mohr
SHORT TERM...Connelly
LONG TERM...Telken
AVIATION...Mohr


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