Area Forecast Discussion
Issued by NWS Huntsville, AL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS64 KHUN 081733

Area Forecast Discussion
National Weather Service Huntsville AL
1133 AM CST Thu Dec 8 2016

For 18Z TAFS.


.NEAR TERM...(Rest of Today)
Issued at 915 AM CST Thu Dec 8 2016

Temperatures at 9 am were in the lower 30s across the higher
elevations of NE AL and southern middle TN to the upper 30s across
the western portion of the forecast area. Extensive cloud cover
remains and area radars were indicating very light reflectivity
returns across portions of northern AL. Given the drier surface
conditions, do not expect any of these returns to reach the ground
and have removed the isolated weather from the forecast. Temperatures
will likely only rise a few degrees above their current values, and
have lowered our forecast highs by a degree or two. Otherwise,
expect a brisk day, as winds remain in the 10 to 15 kt range, with
higher gusts possible.

.SHORT TERM...(Friday through Saturday Night)
Issued at 239 AM CST Thu Dec 8 2016

High pressure continues to push southeast into the area on Friday.
The coldest 850mb temps finally make it to the area and even with
sunny skies, highs Friday won`t make it out of the middle to upper
30s. Wind chills will be a few degrees lower than temps.

Again, lows are always tricky this time of year. Friday night should
feature clear skies and near calm winds setting up excellent
radiational cooling conditions. Guidance is fairly consistent with
forecasting lows around 16-19 degrees but with dew points dropping
into the 14-18 degree range, lows could be a deg or two lower than
currently forecast. With lighter winds, wind chills will be near the
temperature value.

The cold doesn`t last too long this time around as heights start to
rise on Saturday and winds start to turn southeasterly. We will
start to see some high clouds return Saturday afternoon streaming
ahead of a developing system aloft over the upper midwest. Highs
will rebound into the middle 40s but that is still below normal for
this of year. Same story goes for lows: with increasing cloud cover,
5 mph winds and southerly flow lows will rebound back into the upper
20s to lower 30s.

.LONG TERM...(Sunday through Thursday)
Issued at 239 AM CST Thu Dec 8 2016

The extended portion of the fcst is looking more complicated and
unsettled. Starting with Sunday a sfc low/inverted trof will move NE
from the srn plains towards the Great Lakes. This will put the TN
valley in good return flow, however models are showing that most of
the pcpn and best dynamics, will be north of the cwa on Sunday.
Models also are showing that the pcpn may hold off until late Sunday
aftn or even into the evening hours. For now will keep Sunday mrng
dry and bring in slight pops for Sunday aftn. The blended models
then bring in likely pops for Sunday night.

On Monday, a cdfnt associated with the previously mentioned sfc low,
will approach the TN valley by the aftn. However by Monday night
ECMWF and GFS disagrees with what happens to the cdfnt. If GFS is
correct the cdfnt will likely stall out NW of the cwa while a warm
front moves across the area Monday night. On the other hand the
ECMWF looks to bring the cdfnt thru the cwa by Monday night along
with a better chc of pcpn.

Tuesday also looks to be a possible can of worms wx wise as a strong
cdfnt is progged to quickly blow thru the TN valley by Tuesday
night. The main fcst problems for Tuesday looks to be if we will get
any tsra ahead of the cdfnt and any freezing/frozen pcpn behind the
cdfnt. The ECMWF is much less bullish with any tsra than the GFS and
also faster moving the pcpn out of the cwa. The GFS hints at
possible tsra on Tuesday aftn with any rain left over (after
midnight) mixing with or turning to snow. With it being so far out,
will keep the forecast as rain/snow for now.

Both the ECMWF and GFS are showing any pcpn should be over beginning
at 12z on Wednesday as much colder temps once again moves across the
TN valley. Otherwise will keep Wednesday and Thursday dry and cold
with aftn highs arnd 40 and mrng lows in the 20s.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1132 AM CST Thu Dec 8 2016

VFR conditions will prevail at the KMSL and KHSV terminals. Winds
will generally be from the north and lessen a bit overnight. Clouds
will continue to erode through the day, with skies becoming clear
after 03Z.





For more information please visit our website
at is the U.S. government's official web portal to all federal, state and local government web resources and services.