Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 131646 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1146 AM CDT Sun Aug 13 2017

.UPDATE...
Issued at 1125 AM CDT Sun Aug 13 2017

Updated the forecast this morning to lower pops along and west of
the James River valley through this afternoon. CAMS suggest
eastern SD and western MN will see the bulk of the pcpn today.
Strong to severe storms are possible, mainly in our southeast part
of the CWA. Large hail will be the main threat.

&&

.SHORT TERM...(Today through Tuesday Afternoon)
Issued at 422 AM CDT Sun Aug 13 2017

Slow moving wave remains over eastern North Dakota this AM, with the
majority of precipitation just over the North Dakota state line, and
across our Northeast SD/Western MN counties. A few stragglers remain
to the south and west, which belies a marginally unstable atmosphere
overhead. There is an area of clearing that covers much of the CWA
as well, though some lower clouds are also pivoting out of North
Dakota. The afternoon will feature some MLCAPE - generally less than
1500 j/kg, and 20-30kts of 0-6kt shear with mainly unidirectional
westerlies.

Added the mention of fog for tonight with the system slowly
departing the area and a weak ridge axis wrapping down out of Canada.
This is probably not going to be widespread as the areas of decent
precipitation from last evening was fairly sporadic in coverage, and
some of that moisture will mix out today.

The next wave begins to move into the area Monday PM. A warm front
will set up across the area and we also see a fetch from the Gulf of
Mexico develop thanks to a 20-30kt low level jet. This jet will
support morning convection. By the afternoon, the higher dewpoint
airmass will result in MLCAPE values into the 2000-3000j/kg range,
though 0-6km shear is only between 15-30kts. Something to watch
though as low level flow is in the 20-30kt range and there is some
turning from southeast to southwest in the profiles.

.LONG TERM...(Tuesday Evening through Saturday)
Issued at 422 AM CDT Sun Aug 13 2017

The period opens with southwest flow aloft and a trough
transitioning into the Plains. At the sfc, an area of weak low
pressure will interact with shortwave energy aloft to generate some
widespread showers and thunderstorms Tuesday night and Wednesday
morning. Another sfc low will bring some additional showers and
thunderstorms, mainly to the southern cwa, Thursday night through
Friday night.

For the weekend, the upper trough with exit and leave more zonal
flow aloft. Any isolated precip will likely remain to the south
though another front may move through late Sunday night into Monday.

Temperatures under the trough will remain slightly below average
with highs in the 70s east to 80s west. Temps will recover slightly
over the weekend after the trough exits.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday Morning)
Issued at 625 AM CDT Sun Aug 13 2017

Showers and thunderstorms will impact KABR and KATY this morning.
VSBY and CIG may fall to IFR in heavier showers. Another round of
showers and thunderstorms will develop this afternoon. Ceilings
and/or vsby will again fall to MVFR/IFR late tonight near KABR and
KATY in stratus and fog. KPIR will be VFR through the period. KMBG
will improve from MVFR this morning to VFR this afternoon.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...SD
SHORT TERM...Connelly
LONG TERM...Wise
AVIATION...Wise



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