Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 160514 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1214 AM CDT Sun Oct 16 2016

Issued at 853 PM CDT SAT OCT 15 2016

No changes planned. Current tonight period forecast parameters
appear to be working out at this time.

UPDATE Issued at 614 PM CDT SAT OCT 15 2016

See below for an updated aviation forecast discussion for the 00Z


.SHORT TERM...(This Evening through Monday Night)
Issued at 258 PM CDT SAT OCT 15 2016

Weak high pressure overhead will shift east tonight with an
increased pressure gradient developing across the state. Pressure
falls will be around 8mb/6hrs through the day, with about a 12mb
pressure gradient across the state at its peak. NAM mixed winds top
out around 30kts through the course of the day. Add in the very dry
ambient conditions and favorable mixing as winds shift to the
southwest around a low moving across North Dakota, along with a
tongue of higher 850mb temperatures close to +20C and we will see
conditions favorable for erratic fire behavior. Additionally, there
will be a wind shift in the late afternoon through the evening,
though weak CAA, a weak gradient, and pressure rises only topping
out around 6mb/6hrs will mean post frontal winds should drop off
quickly. To the east, a plume of higher dewpoint air will move
across the area. MUCAPE values top 1000 j/kg, however looking at NAM
profiles, moisture is limited to 10 to 12Kft so limited mention to
just showers.

Expect a brief period of stronger Coteau downslope winds with the
shift to south-westerlies as the low moves over eastern North Dakota
Sunday night, but this would last an hour or two before winds
continue to round to the northwest.

The next feature of note is a wave ejecting out of the rockies
Monday. 12Z GFS has increased the Q vector signature over northern
counties compared to previous runs, and now SREF probabilities for
measuring are up around 70 percent. We still have a problem
saturating the profile initially but with cooler mid level
temperatures the expectation is for a few hundreds of QPF. Also of
note is the NAM MUCAPE values increasing to around 500 j/kg, but
this is spread through the moist adiabatic profile. With omega
values around 500mb topping 20 microbars anticipate a few rumbles of
thunder/convective elements with some localized higher QPF.

.LONG TERM...(Tuesday through Saturday)
Issued at 258 PM CDT SAT OCT 15 2016

Mid level southwest flow will be dominant over the area through
early Wednesday morning, then a shortwave trough will move through
and switch the flow to northwesterly for the remainder of the
extended period.

At the surface, the region will be between low pressure to the east
and high pressure to the west when the period begins. The leading
edge of the high will track across the Tuesday afternoon and Tuesday
night, with the main high settling in over the Northern Plains by
Wednesday night. The high gets pushed east/southeast Thursday night
by an approaching trough, which looks to push across the region on
Saturday. Little in the way of low or mid level moisture through the
period, so expecting a completely dry extended period.

Tuesday will be the warmest day of the period, with highs mainly in
the 60s. Will then see highs mainly in the 50s, with just a hint of
a warm up toward the very end of the period. Overnight lows will
generally be in the 30s.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1212 AM CDT SUN OCT 16 2016

VFR conditions are expected through the valid taf period until
perhaps Sunday evening when some MVFR cigs may form near KATY.


SD...Red Flag Warning from 1 PM this afternoon to 7 PM CDT this
     evening for SDZ267.



SHORT TERM...Connelly
LONG TERM...Parkin
AVIATION...TDK is the U.S. government's official web portal to all federal, state and local government web resources and services.