Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 180810

Area Forecast Discussion
National Weather Service Aberdeen SD
310 AM CDT Wed Oct 18 2017

.SHORT TERM...(Today through Friday Afternoon)
Issued at 309 AM CDT Wed Oct 18 2017

The main story today will be the result of the sfc low moving
east into central and northern Manitoba, and the cold front across
that will quickly push across the Dakotas by late morning. Although
temperatures will still be above normal, they will be over 10F
cooler than yesterday as breezy northwest winds push cooler air into
the region. Expect winds of 15-20kts 15-19Z west, and 17-21Z east.
Gusts of 20 to near 30kts are also expected behind the cold front.
While relative humidity does bottom out around 20 percent near and
west of the Missouri River from around 18-22Z, the peak winds should
be before this period. Will continue to highlight the breezy winds
and relative humidity values less than 25 percent along and west of
the James River Valley in the fire weather products.

High pressure over western SD at 18Z will shift over central NE by
00Z Thursday, with a ridge extending across the entire forecast
area. The sfc high will continue to sink southeast, and across IA
Thursday morning. The pressure gradient will increase in between
this exiting high and low pressure over southwestern Canada. General
zonal flow aloft will be replaced by a ridge Thursday afternoon,
that will stretch southeast through the Gulf of Mexico. Temperatures
will rebound back into the 70s, with breezy afternoon winds from
south central SD through our eastern counties. This will again be
offset from the area of lowest relative humidity values, west of the
Missouri River.

The 500mb ridge will move to the eastern U.S. Thursday night and
Friday, with southwesterly flow setting up late Thursday afternoon
through Friday. Eastern SD and western MN will again be the focus
for breezy southerly winds Friday afternoon, as high pressure
remains at the sfc over the eastern U.S., and low pressure crosses
into south central Canada (with a trough extending south over
eastern MT and the western Dakotas late in the day. Did increase
winds Friday from a general model blend, with some gusts of 30 to
near 35kts not out of the question near the Sisseton Hills.

.LONG TERM...(Friday Evening through Tuesday)
Issued at 309 AM CDT Wed Oct 18 2017

It`s not looking all that great for precipitation chances Friday
night into Saturday, even though the cwa will be under southwesterly
flow aloft. Model consensus remains that shortwave energy will work
through the region during that time. But, currently, precipitation
amounts being forecast are not all that much and not widespread in
coverage. What seems like a higher confidence forecast element, at
this time, is breezy to windy south-southwesterly winds Friday
night. By the start of next week, when the pattern over this cwa has
transitioned to northwest flow influence, there is a little bit of
"cold air instability" precipitation potential mainly across the far
northeastern portion of the cwa and mainly Monday into Monday
evening. As far as temperatures go, the cooler conditions that set
up over the region on Saturday are briefly usurped by a little bit
of low level warm air advection on Sunday before low level cold air
advection sets back up early next week.


.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1230 AM CDT Wed Oct 18 2017

VFR conditions will prevail across the area overnight and through
the day Wednesday. Winds will become northwesterly at 15 to 30 knots
by mid morning, and will continue until early evening before
becoming light and variable.




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