Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 241734 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1234 PM CDT SAT SEP 24 2016

.UPDATE...
Issued at 1106 AM CDT SAT SEP 24 2016

Low pressure center is moving into southwest ND with frontal
boundary pushing into central SD. Have seen a few scattered light
showers this morning ahead of the front, moving northward. Hi-res
model guidance continues to suggest an uptick in shower and storm
activity later this afternoon across the eastern CWA so will
continue to monitor. Threat remains for a few stronger storms
capable of gusty winds, and cannot rule out an isolated weak
tornado somewhere across eastern SD into west central MN given the
high shear environment. Made a few adjustments to POPs based on
current radar trends and anticipated activity this afternoon.
Otherwise, minor tweaks elsewhere in the forecast, which is in
generally good shape with highs rising into the 70s to around 80
degrees.

&&

.SHORT TERM...(Today through Monday)
Issued at 407 AM CDT SAT SEP 24 2016

The large 500MB low rotating over WY early this morning will eject
northeastward to far southwestern ND by 00Z this evening. The sfc
low currently over our far western counties will slide directly
northward, to around Minot by the end of the day. This will allow
showers and thunderstorms to develop this afternoon along a cold
front moving over our eastern counties. Fcst models continue to look
less and less impressive with the convective shower potential until
after 18Z and closer to 21Z. Did a first cut to limit the potential
until later in the morning/afternoon. Would not be surprised if
additional cuts will be needed. Will be under a high low level shear
environment with moderate CAPE values, with MLCAPES of 750-1000J/kg.
The focus still looks to be from Brown and Spink Counties and
eastward.

The focus for late tonight through early Sunday afternoon will shift
from thunderstorm potential to potential Wind Advisory criteria.
Three hour height falls of 3-5MB. Included the potential for strong
northwesterly winds of 20-30mph with gusts of 30 to near 45 mph
mainly west of the James River Valley. Expect highs back in the 60s
for highs Sunday afternoon. While some showers will be rotating
around the back side of the exiting low, mainly dry conditions are
expected. Any lingering showers should shift into MN late Sunday
evening, with dry weather and a slight warm up for Monday. Still
anticipating RH values over much of the area to fall in the 25 to 35
percent range, despite temps still only in the 60s.

.LONG TERM...(Tuesday through Friday)
Issued at 407 AM CDT SAT SEP 24 2016

The 00Z GSM deterministic solutions for Monday night through the end
of the period maintain uncanny similarity in their respective mass
fields. The GFS/Canadian and ECMWF models are similarly timed now in
handling the cut-off upper low energy late in the week, and
superblend slt chance pops showing up mainly late Thursday night
through Friday night appear appropriate right now to handle precip
potential. Otherwise, the forecast period is dry and near
climatological normal for temperatures while northwest flow aloft
transitions to an upper level ridge during the period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1230 PM CDT SAT SEP 24 2016

A mix of vfr/mvfr cigs will continue through the evening.
Thunderstorms may develop or move in from the south closer to 21z
and affect KATY. As the cold front moves east tonight and Sunday,
winds will shift to the northwest and become gusty at 20 to 35
kts.

&&

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

$$

UPDATE...TMT
SHORT TERM...KF
LONG TERM...Dorn
AVIATION...Wise



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