Area Forecast Discussion
Issued by NWS Huntsville, AL

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054
FXUS64 KHUN 250506
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
1106 PM CST Fri Feb 24 2017

.UPDATE...
For 06Z TAFS.

&&

.NEAR TERM...(Tonight)
Issued at 855 PM CST Fri Feb 24 2017

Currently tracking two lines of showers with some embedded
thunderstorms. The first batch associated with the pre frontal trough
is moving through NW AL while the secondary area, associated with the
front itself, continues to drift through central MS. 00z soundings
from OHX and BMX did show some moderate instability and generally
favorable lapse rates to support a few strong thudnerstorms with an
isolated severe thunderstorm through the rest of tonight. With any
storm, we cannot rule out a damaging wind gust, brief heavy rainfall,
and frequent cloud to ground lightning.

With the line(s) of storms expected to shift out of the area after
midnight, cooler air will begin to usher in with high pressure
 over the area tomorrow. Current forecast is on track and only minor
changes made.

.SHORT TERM...(Saturday through Sunday)
Issued at 305 PM CST Fri Feb 24 2017

A fairly pleasant weekend is in store across the TN Valley,
especially compared to the last week or so. High pressure will build
across the area on Saturday, keeping skies clear. However, the CAA
will continue and high temps will only rise into the mid 50s. As the
center of the surface highs moves through the area Saturday night,
winds will become calm and skies will remain clear. So good
radiational cooling conditions will send our overnight lows into the
upper 20s across the majority of the area. Winds will shift to the
south on Sunday as the high moves east of the area. Southerly flow
will advect warm and moist air back towards the region and daytime
highs on Sunday will be in the mid to upper 50s.

.LONG TERM...(Sunday night through Thursday)
Issued at 305 PM CST Fri Feb 24 2017

The extended starts off in an unsettled weather pattern
leaving some chance of precip in the forecast until Wednesday night.
A sfc high off the Atlantic coast will provide good return flow.
Temps will remain above normal and moisture will advect into the
region on Monday and Tuesday as a broad trough across the western
half of the CONUS provides southwesterly flow aloft. A few
disturbances will slide across the previously mentioned broad trough,
and combine with a LLJ of 30-40kts on Monday morning, resulting in
showers returning to the forecast. This activity will spread eastward
throughout the day and linger into Tuesday with a few thunderstorms
possible as well. Kept in a slight chance of thunder Monday
afternoon/evening as soundings continue to show elevated CAPE but a
persistent low-level cap throughout the day.

As the upper-level trough shifts eastward on Tuesday, a sfc low
develops in the Central Plains. As the low lifts NE into the Great
Lakes on Wednesday, the associated cold front will move into the TN
Valley. Disagreements continue between models with the timing of the
cold front and QPF.  The GFS had a faster arrival and more QPF than
the ECMWF with this cold front. Leaned towards the ECMWF solution
for this forecast package. Both agree that convection will occur
ahead of the front and that stronger storms are possible Wednesday
with low-level shear of 30-40kts, CAPE over 500 J/kg and steep lapse
rates in the mid-layer. However, will have to see how the timing
plays out with the cold front.

After the cold front passes, cooler and drier air filters in. Temps
will cool back to more seasonable values with highs in the upper
50s, overnight lows in the mid/upper 30s.


&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1105 PM CST Fri Feb 24 2017

The prefrontal round of showers and a couple embedded thunderstorms
will continue to shift east of the terminals through the night.
However, the showers along the front itself will begin to affect MSL
and HSV within the next couple of hours. Main impact will be the wind
shift to the NW with some gusts approaching 20kt through the early
morning. May have some brief periods of MVFR cigs, but not confident
enough to include in forecast. VFR conditions will prevail by
sunrise.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&

$$

NEAR TERM...Barron
SHORT TERM...73
LONG TERM...JMS
AVIATION...Barron


For more information please visit our website
at weather.gov/huntsville.



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