Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 300914
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
414 AM CDT MON MAY 30 2016

.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 414 AM CDT MON MAY 30 2016

Currently watching showers and thunderstorms on the nose of the low
level jet from Sully county southeast through Hand and Buffalo
counties. Models show the low level jet shifting to the east this
morning but weakening. CAM solutions all over the place in regards
to areal coverage of any showers or storms that develop over the
next several hours further east over northeast SD. With the
weakening low level jet, will keep pops on the low end through the
remainder of the morning for the eastern CWA.

Main focus will be on this afternoon and evening as the severe storm
threat will increase with the approach of a cold front and good
upper level dynamics/forcing. Plume of moderate instability develops
this afternoon as low level moisture increases and lapse rates aloft
steepen. 0-6km bulk shear eventually reaches 40 to 50 knots over the
western CWA by late afternoon. Expecting strong to severe storms to
develop over the western CWA by mid to late afternoon ahead of the
advancing cold front. Will also be seeing a subtle warm front
lifting northward through the afternoon, with a slight backing of
the winds possible over north central SD. Sig Tor parameters of 1 to
2 showing up over this area during the late afternoon. Cannot rule
out an isolated tornado over north central SD with 0-1km shear in
the 10 to 20 knot range. As we get into the evening hours, expecting
convection to organize into more of a linear fashion ahead of the
cold front as activity marches east through the rest of the CWA.
Threat for large hail and gusty winds within supercellular
structures early on over the western CWA will eventually transition
to more of a strong wind threat into the evening hours further east
from the James Valley and points east. Storms will exit the CWA
during the nighttime hours, likely fairly early as CAM solutions are
showing a pretty quick movement eastward once the MCS/linear mode
gets going.

Tuesday and Wednesday will feature a large upper low moving across
ND and into MN. Rather chilly air aloft is associated with this low
with highs dipping down into the 60s and 70s both days. Tuesday
appears to be dry slotted for the most part which will cut off
precip chances for eastern areas. Further west, a bit more moisture
to work with so with the cool air aloft and steep lapse rates, could
see widely scattered afternoon showers and thunderstorms. Shower
threat will continue for the far northeast CWA on Wednesday as the
upper low departs.

.LONG TERM...(Wednesday Evening through Sunday)
Issued at 414 AM CDT MON MAY 30 2016

The models remain consistent in forecasting a shift to a positive
PNA pattern over the CONUS during the period. Through out the long
term mid level heights will continue to increase...with a consequent
decrease in pcpn chances. About the only chance for meaningful pcpn
is on Friday as a frontal boundary marches across the forecast area.
But even then pcpn coverage looks to be sct at best.  Temperatures
should average out about normal for most of the period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1218 AM CDT MON MAY 30 2016

Except for IFR vsbys/cigs in heavy thunderstorms tonight and
Monday, VFR will be the prevailing weather conditions across all
four terminals during the TAF valid period. Isolated to scattered
/elevated/ showers and thunderstorms are beginning to develop
across central South Dakota where the best low level jet forcing
and low level moisture advection are overlapping. Convection
should continue to expand north and east through mid-morning on
Monday /appx 15z/. While most of tonight`s convective activity
will be sub-severe, a few storms could produce hail. There is a
greater probability for scattered to numerous strong to severe
thunderstorms later in the afternoon and on into the evening hours
on Monday.

&&

.ABR Watches/Warnings/Advisories...
SD...NONE.
MN...NONE.
&&

$$

SHORT TERM...TMT
LONG TERM...TDK
AVIATION...TDK



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