Area Forecast Discussion
Issued by NWS Aberdeen, SD

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507
FXUS63 KABR 211525 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1025 AM CDT THU JUL 21 2016

.UPDATE...
Issued at 1021 AM CDT THU JUL 21 2016

Will continue to monitor convection across northern CWA but expect
it to die slowly through the rest of the morning. Not sure about
convection along the front this afternoon but again will leave as
is given isold storms that fired in the heat of the day yesterday.
temps should be okay.

&&

.SHORT TERM...(Today through Saturday Afternoon)
Issued at 409 AM CDT THU JUL 21 2016

Forecast challenges include improperly modeled dewpoints, excessive
heat potential and thunderstorm chances.

Currently, a cold front is moving through north central South
Dakota while an outflow boundary from North Dakota convection is
trying to move southward through the cwa out ahead of the frontal
boundary. Temperatures are still mainly in the 70s this morning.

The only change to the Excessive Heat headline was to take out
Corson, Campbell and McPherson counties this morning. The rest of
the warned area remains either solidly or marginally within the
headline criteria heat and humidity today and Friday.

Some of the GSM and CAM output this morning is still hinting at the
potential for a storm or two to pop through the mid-level capping
inversion this afternoon along or just north of this frontal
boundary moving south-east through the cwa today. Collaborated a
small pop for that potential, but not all that confident in seeing
updrafts overcoming the mid-level thermal cap in place.

Same story Friday night and Saturday. Models depict a somewhat
stronger frontal boundary entering the scene and try to develop
convection along/ahead of the boundary. There seems to be adequate
shear/instability for strong storm potential, but again the forecast
mid-level temperature field shows no signs of cooling off enough
over central/northeast South Dakota during the short term forecast
period to support organized convective development.

Only changes made to the temperature forecast were to shave a few
degrees off of the forecast high temperatures today and Friday for
areas expected to be in the slightly cooler/drier post frontal
environment at peak heating.

.LONG TERM...(Saturday Evening through Wednesday)
Issued at 409 AM CDT THU JUL 21 2016

Surface trough will be moving into MN Saturday night with cooler and
drier air working into the CWA. Will maintain some low POPs across
the eastern CWA Saturday evening in the vicinity of the surface
trough as it begins departing into MN. On Sunday, models are
painting a mostly dry scenario as high pressure works into the area
with drier air (50s dewpoints) in place. Return flow and moisture
look to return to western and central SD on Monday as the surface
high moves off to the east. Precip chances increase once again as we
head into Tuesday and Wednesday as models show an area of low
pressure moving across the region.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 630 AM CDT THU JUL 21 2016

VFR conditions are expected to prevail during the TAF forecast
period. Currently seeing some -SHRA/-TSRA skirting the ND/SD
border. Current projections keep this activity away from KMBG but
will continue to monitor for possible insertion of VCSH/VCTS.


&&

.ABR Watches/Warnings/Advisories...
SD...Excessive Heat Warning until 7 PM CDT /6 PM MDT/ this evening for
     SDZ006>011-015>017-021.

     Excessive Heat Warning until 7 PM CDT /6 PM MDT/ Friday for
     SDZ018>020-022-023-033>037-045-048-051.

MN...Excessive Heat Warning until 7 PM CDT this evening for MNZ039-046.

&&

$$

UPDATE...TDK
SHORT TERM...Dorn
LONG TERM...TMT
AVIATION...TMT



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