Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 190254 AAB

Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
854 PM CST Thu Jan 18 2018

.NEAR TERM...(Tonight)
Issued at 853 PM CST Thu Jan 18 2018

Very quiet weather throughout the Tennessee Valley tonight as high
pressure has established itself at the surface and aloft. A clear sky
and a cold, dry air mass continue to prevail with another chilly
night anticipated across the region. However, a subtle (but
noticeable) moisture creep has taken place in the boundary layer
with dewpoints now in the mid to upper Teens. This added moisture
will help keep lows anywhere from 5-10 degrees warmer than last
night, despite the good radiational cooling that has taken place this
evening. Generally, lows will bottom out in the mid to upper Teens,
through a few sheltered "cool" spots in the Bankhead National Forest
and along the Plateau region of far NE AL and S. Mid TN could drop to
around 10 degrees by daybreak.

Given the higher RH values around daybreak, we`ll need to watch for
the possibility of some patchy freezing fog, mainly around area
lakes and river in the usual fog prone areas. Have added a mention of
this to the forecast from 06-14z. Folks traveling near these areas
should remain vigilant for the possiblity of this.

.SHORT TERM...(Friday through Sunday)
Issued at 316 PM CST Thu Jan 18 2018

Warmer--but still dry--conditions will prevail for the weekend as
the surface high departs the region to the east, leaving return flow
in its wake, and a deep trough comes ashore along the Pacific coast.
Temperatures will easily rebound back into the 40s Friday, 50s
Saturday, and 60s Sunday. MOS/blended guidance consensus is in solid
agreement with not a ton of spread during that timeframe. However,
as with most rapid warm air advection patterns in the winter, this
comes with a cost, as clouds will redevelop across the area
Saturday. Although there will be plenty of cloud cover, model
consensus does not indicate enough deep-layer moisture for rain
chances through Sunday.

.LONG TERM...(Sunday night through Wednesday)
Issued at 316 PM CST Thu Jan 18 2018

Rain returns to the forecast Sunday night through Monday but warmer
temperatures stick through the extended forecast! A strong trough
will deepen as it moves into the Great Lakes region on Monday. As
the sfc low lifts across the Midwest and into the Great Lakes on
Monday, showers and thunderstorms will develop along the cold front.
Expect breezy southerly winds ahead of the front Sunday night
allowing warmer than normal overnight lows in the mid/upper 40s. The
front will move quickly across the forecast area Monday bringing
showers, isolated thunderstorms and breezy conditions, then exit by
late Monday night. Soundings continue to show PWATs just over 1 inch,
a fair amount of shear and a lack of CAPE. The models are in better
agreement on the timing of the system, however the ECMWF continues to
be the slower solution. Temperatures will warm up into the upper 50s
on Monday and since this was a Pacific and finally not an Arctic
front, temperatures will not drop significantly behind the front. You
will feel the biggest change in the overnight lows on Monday as
temps will be back in the mid 30s. However, sfc high pressure will
keep conditions dry and temps near normal Tues and Wed with highs in
the lower 50s and overnight lows in the lower 30s.


.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 511 PM CST Thu Jan 18 2018

VFR conditions will be the predominant flight category at each
terminal through the period, with light winds and a mostly clear sky.





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