Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 261150

Area Forecast Discussion
National Weather Service Huntsville AL
650 AM CDT Sun Mar 26 2017

For 12Z TAFS.


.NEAR TERM...(Today)
Issued at 528 AM CDT Sun Mar 26 2017

Most of the lingering rainfall/showers have shifted e of the cntrl TN
Valley into n cntrl GA this early Sun morning, although a couple of
spotty showers were moving newd across the I-65 corridor attm. The
cold front to the w looks to have stalled along the MS River, which
is not surprising based on the latest nwp guidance. This does help to
explain the lower cloud cover which has spread ewd into the local area
given the lack of any low level mixing. Sfc winds out of the s near 10
MPH with higher gusts are also well entrenched across the region,
and this trend looks to persists for much of the day. Latest models
are hinting at some convective redevelopment later today given some
weak isentropic support in place. However, the lack of a better
lifting mech may only warrant iso/sct showers/tstms at this point.
Even with skies remaining predom mostly cloudy, afternoon temps look
to trend seasonably warm with highs mainly in the lower/mid 70s.

.SHORT TERM...(Tonight through Tuesday night)
Issued at 528 AM CDT Sun Mar 26 2017

Lingering showers/tstms should then quickly taper off this evening
with the loss of latent heating and the frontal boundary to the w
remaining in place. Cloud cover in fact may actually diminish some
this evening, as a quick shot of drier air around H5-H7 traverses ewd
across the region. Clouds will then return heading into Mon morning,
as a series of upper waves, associated with a trough axis exiting
the mid/srn Plains states, moves ewd across the Midwest/mid TN Valley
areas. Parent sfc low associated with the upper trough pattern looks
to move ne out of the srn Plains and into the OH Valley by late Mon.
There`s quite a bit of spread in the global models Mon afternoon wrt
convective development in response to the passing upper disturbances
and moisture thickness, with the 00Z ECMWF/GFS the more aggressive
solutions. In any case, will advertise scattered showers/tstms in the
forecast Mon as a reasonable compromise for now. Convective activity
is then xpcted to increase Mon night into Tue, as the upper trough
continues to move e across the OH Valley and towards the mid Atlantic
Basin. With the sfc low also lifting newd into the mid Atlantic
states, this should finally allow the stalled front to the w to surge
ewd, with showers/tstms increasing along/ahead of the sfc boundary.
The front then looks to clr NE AL Tue afternoon, with rainfall
quickly tapering off from the w. Other than cloud cover diminishing
some Tue night, not xpcting a real temp drop/cool down with this next
front, given the fact that the wind field turns more wly by Wed,
thereby limiting any real cold air advection into the region.

.LONG TERM...(Wednesday through Saturday)
Issued at 528 AM CDT Sun Mar 26 2017

Showers and thunderstorms will continue to be a rinse and repeat
phrase heading into the extended forecast. On the flip side, look for
near 80 degree temps the latter half of this week! It will not be
the first time that we hit 80 degrees this month, nor this year, but
it will be welcomed.

On Wednesday, a weak ridge will build across the region, however a
stalled out front to our south could push a few showers/thunderstorms
into our area. Wednesday night will be dry across the board.

The fate of our next system coming out of the Rockies will depend on
the interaction between the trough up in New England and with the
short wave in the N Plains. The models diverge quickly heading into
Thursday on what the system will do once it leaves the Rockies. The
ECMWF allows the New England system to progress off the coast faster
and the N Plains flow allows the closed low to open up, deepen and
neg tilt the trough as it approaches the TN Valley by Thurs
Night/Friday. This would bring the associated sfc low up towards the
Great Lakes, and put the TN Valley in a favored warm sector but not
by much. As this set up would favor strong/severe weather, the GFS
offers a different outlook. As the timeframe is not far off, as the
trough is dragged NE, it stays closed off and very positively tilted
as it moves across with the sfc low tracking just off to our NE then
into the OH Valley. Will look for further model consistency with
upcoming runs to determine storm strength and hazards. All in all,
look for showers and thunderstorms to move into the forecast area by
Thursday, spreading west to east, with thunderstorms Thursday night
into Friday. Precip will taper off thereafter as the sfc low lifts NE
and ridge begins to build in. This will bring drier air and a little
bit cooler temps as we head into the weekend.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 650 AM CDT Sun Mar 26 2017

Low clouds, with bases around 1K ft or less, are well entrenched
across the area this early Sun morning, given the lack of any mixing
in the lower levels. Cold front to the w has stalled, with sly winds
near 10KT with higher gusts prevailing at the two main terminals.
Iso/sct shra/tsra are possible later today as well, although the prob
is fairly low attm. Cloud bases are xpcted to lift above VFR levels
going into the afternoon hrs, as daytime heating allows some of the
lower clouds to mix out/sct.





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