FXUS64 KHUN 211704 AAA

Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
Issued by National Weather Service JACKSON MS
1104 AM CST Wed Feb 21 2018

For 18Z TAFS.


.NEAR TERM...(Rest of Today)
Issued at 855 AM CST Wed Feb 21 2018

Latest rap and satellite imagery showed the forecast area under the
influence of a strong midlevel ridge off the Atlantic Coast with
southwest flow aloft. A frontal boundary was observed just to the
northwest. Latest Cam guidance will continue showers for this
morning which will become convective by afternoon and will increase
from the northwest late this morning into the afternoon. Current pop
coverage and high temperatures in the 70s look to be on track./17/

.SHORT TERM...(Thursday through Friday)
Issued at 343 AM CST Wed Feb 21 2018

The NAM/SREF and even the GFS all pivot the cold front back northwest
a bit on Thursday morning, and thus the convergence needed to support
widespread precipitation. Thus, the warm sector will remain in tact
for our area, keeping us unseasonably warm. We could conceivably be
dry in the warm sector due to a slowly building capping inversion.
Will leave a token 20-30 PoP for consistency sake, but this may be
dropped further. This will also be the case Thursday night into
Friday. Temperatures will remain very mild both Thursday night into
Friday. Highs should once again reach the mid 70s to around 80.

.LONG TERM...(Friday night through Tuesday)
Issued at 343 AM CST Wed Feb 21 2018

As the ridge remains anchored in the Western Atlantic it continues
to pull warm/moist air into the region and keeps the frontal boundary
to our NW for just a little bit longer. Friday night, overnight lows
will be mild in the upper 50s/lower 60s under overcast skies with
rain chances return Friday night due to weak isentropic lift.

The ridge will further weaken as a deepening trough swings out of
the Four Corners region on Saturday. Surface cyclogensis will develop
near TX/OK on Saturday and follow the ridge flow into the Great
Lakes by Sunday. This pattern movement will give the push the stalled
front needs and it will move into NW AL around 06Z Sunday.

As previously mentioned, there will be a plentiful amount of
warm/moist air in place ahead of the front. Unseasonably warm
temperatures, dew points in the 60s and PWATS up to 1.5 inches.
There is also a little bit of CAPE and a sufficient amount of shear
with 0-1km ~30kts and 0-3km ~40kts. There will be showers and cloud
cover ahead of the line, however cannot rule out a strong to severe
storm. The line would move out of the forecast area by early
afternoon Sunday, ~18Z. Models seem to be more in agreement with the
arrival timing but the GFS is still a little bit faster with moving
it out of the forecast area.

There is a chance that the front could stall out in Central AL,
leaving a few showers in the forecast for Monday. Will see how the
progression of the weakening ridge goes. Otherwise, Monday night and
Tuesday are looking rain free! Temps will still be warmer than normal
behind the front with highs on Monday and Tuesday in the mid 60s
with lows in the 40s.


.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1104 AM CST Wed Feb 21 2018

Late this morning MVFR TO VFR ceilings was noted across the forecast
area. Area radars were picking up isolated warm advection showers
with a better shower coverage near the frontal boundary to the
northwest. Moist southerly flow will continues with gusts near 20kt
expected, especially from late morning into the afternoon. Ceilings
will lift out to VFR levels across the region except where showers
occur with some embedded thunder. A line of showers will approach
KMSL from the northwest for this afternoon. Showers will remain in
the vicinity of KMSL through this evening ,with a larger area of
showers and possibly thunderstorms arriving between 00-04Z.At KHSV,
the probability of showers or thunderstorms is considerably less, so
have left out of the forecast. However, lower ceilings of 015-018agl
should return by 06Z then lowering to 007-009agl by 10-11z then
rising to 015 agl by 14-15z at both KMSL and KHSV./17/





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