Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 251137 AAA

Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
637 AM CDT THU AUG 25 2016

For 12Z TAFs.


(Issued 345 AM CDT THU AUG 25 2016)
Quiet and mild wx conditions prevail across the cntrl TN Valley this
early Thu morning, as high pressure at the sfc and aloft remains
entrenched from the srn Atlantic Basin swwd into the wrn Gulf Coast.
Any convective activity is pretty much working its way around the
periphery of the stacked ridge pattern over the Lower MS Valley and
in parts of the OH Valley states according to the latest IR/WV sat
imagery. Closer to home, convection may have a tough time breaking
through the ridge axis unless one of these weak embedded upper waves
are able to rotate closer to the center of the high placing them in
better proximity to the mid TN Valley. In any case, rain chances
later today will be fairly low, with any precip coverage mainly
limited to iso at best given the lack of a better lifting mech. This
should also translate into another seasonably hot and humid day
across much of the area, with highs climbing well into the mid 90s
over the cntrl/wrn zones and heat indices in the 100-105F range. Heat
indices may in fact linger near the 105F mark for a couple of hrs
this afternoon across portions of nw AL, but the areal coverage is
not xpcted to be enough to warrant an advisory at this point.

Unfortunately the forecast in the short term is going to play out
like a broken record going into the weekend period. Both the sfc and
upper ridge patterns look to remain fairly stagnant over much of the
region heading into Sat. However, the latest short term guidance is
still hinting at a weak frontal boundary settling into the nrn half
of the mid TN Valley during the day Fri, but stalling well n of the
local area. This may at least result in a slightly higher chance for
showers/tstms Fri afternoon as low level convergence increases a bit
into the region. Otherwise, iso mainly afternoon showers/tstms look
to be about it for the cntrl TN Valley through the weekend period,
again influenced mainly by weak upper disturbances working their way
ewd along the nrn fringe of the upper ridge axis. Unseasonably warm
and humid wx conditions will also continue into Sat courtesy of the
sfc/upper ridge in place, with afternoon highs again climbing into
the mid 90s for the cntrl/wrn areas and associated heat indices in
the 100-105F range during max heating.

The latter half of the forecast will be somewhat influenced by the
tropical wave/system moving into the extreme sern Gulf out of the
Caribbean waters. The global model spreads/biases have shifted a bit
ewd with their latest track, now taking the system across the FL
panhandle and into the srn Atlantic by the middle of next week. The
latest forecast track looks to reflect this trend as well, although
this remains a highly uncertain/variable system given the model
intensity/spread. Nevertheless, if this system does trend more ewd
along the srn Atlantic Coast, this could translate into slightly
drier air filtering into much of the region for the second half of
next week.



For 12Z TAFs: At KMSL, patchy MVFR fog/haze is possible at daybreak.
VFR weather otherwise should prevail across the central Tennessee
Valley the next 24 hours, as surface high pressure centered just east
of the region controls the weather. Despite this high, strong daytime
heating and available moisture could result in isolated showers and
thunderstorms this afternoon. No mention of precip was included in
the TAF`s, given very slim chances. Light SE winds this morning
should become southerly around 5kt this afternoon, then become light
and variable after sunset this evening.



.HUN Watches/Warnings/Advisories...


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