Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 222348
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
548 PM CST Sun Jan 22 2017

.UPDATE...
For 00Z TAFS.

&&

.NEAR TERM...(Tonight)
Issued at 203 PM CST Sun Jan 22 2017

Rapidly deepening surface low was located near Clanton, Alabama early
this afternoon with sub 990 millibar pressures now noted in central
Alabama. Pressures have been dropping steadily all day across north
Alabama with a 10 mb drop noted since late last evening.

Regional radars show a well defined MCV/QLCS structure on the
east/northeast flank of this low from near BHM to Troy. Rather
interesting semi-cellular structures were located within this line
and will need to be monitored as they progress further north this
afternoon/evening. Further to the west, a broad expanse of
light/moderate rainfall was located in the comma head region of the
system. This entire complex was pinwheeling slowly to the north
toward the Tennessee Valley.

Main questions for tonight will be precipitation amounts and
convective potential. Have included isolated thunderstorms through
this evening east of I-65 where some modest MLCAPE is noted and
ascent will be maximized. Also enhanced QPF in this area slightly.
Overall, additional rainfall of 3/4 of inch to perhaps locally 2
inches may push the Paint Rock to near flood but not expecting
widespread issues.

Precipitation should begin to wind down after 08-09z as surface low
rotates into northeast Georgia. Gradient will tighten significantly
however, and after coordination with surrounding WFOs, have issued a
wind advisory beginning at 09z.

.SHORT TERM...(Monday through Tuesday)
Issued at 203 PM CST Sun Jan 22 2017

Be sure to double up on the hair spray on Monday as those winds will
be cranking, especially through midday. The high resolution guidance
indicates a 10 millibar surface gradient from west/east across the
state and 925 millibar winds approaching 50 knots. This will likely
equate to gusts of 40 mph, perhaps higher over elevated areas. We may
see some light rain/showers linger in the eastern counties through
midday and included the PoPs from the blended suite of guidance. Also
held the clouds in through early afternoon based on a rather stout
low level inversion in place.

Surface high builds across the region Monday night with temperatures
dropping down into the 30s for the first time in over 10 days. We
should see a rather nice warmup on Tuesday with a quick transition to
return flow by the afternoon.

.LONG TERM...(Wednesday through Sunday)
Issued at 203 PM CST Sun Jan 22 2017

At the start of this period (Wednesday and Wednesday night), a
passing upper level system mainly south of the region, in a zonal
predominate cyclonic flow south of an upper low, will bring rain
chances back to the Tennessee Valley for the mid week. Decent amount
of upglide in the 290-295K region should result in mostly light and
stratiform type rain. This rain will come to an end during Wed night,
as a cold front pushes across the forecast area. High temperatures in
the low/mid 60s on Wednesday will be the last of a warm trend for a
while, as cooler air will filter in for the latter half of the week
and upcoming weekend.

We are currently in the midst of the 3rd longest stretch in January
of above freezing temperatures. This will be coming to an abrupt end,
as temperatures for the latter week and beyond will cool close to,
or below seasonable norms (around 52/32 by the upcoming weekend). As
noted above, highs on Thursday will struggle into the mid/upper 40s.
This cooler trend thanks to a continuing northwest flow and lower
heights/thickness values --- this is despite partly to mostly sunny
skies. Night-time lows Thursday and Friday night will cool to around
freezing both nights, and likely below freezing for the weekend.
Conditions appears will be dry into early next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 548 PM CST Sun Jan 22 2017

Mod/heavy shra are affecting the KHSV terminal attm, with sfc winds
gusting near 15-25MPH at times. With an area of enhanced rainfall
continuing to affect the I-65 corridor, these conds will likely
continue at KHSV for another 1-2 hrs. Light ra/shra are affecting
the KMSL terminal attm, although some of the heavier shra may
approach this airport from the e over the next 1-2 hrs. The threat
for +shra affecting the KMSL airport though is fairly low. Sfc winds
turning toward the wnw and increasing to around 15MPH with higher
gusts will develop at both main airports later this evening, with IFR
cigs just under 1K ft developing. Rainfall should taper off from the
w near 06Z, with gusty winds continuing and cigs perhaps lifting
more into the MVFR cat, or into the 1-2K ft range heading into the
early morning period.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Wind Advisory from 3 AM to 6 PM CST Monday for ALZ001>010-016.

TN...Wind Advisory from 3 AM to 6 PM CST Monday for TNZ076-096-097.

&&

$$

NEAR TERM...15
SHORT TERM...15
LONG TERM...RSB
AVIATION...09


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