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Area Forecast Discussion (AFD)

Issued by Huntsville, AL (HUN)

FXUS64 KHUN 131149

Area Forecast Discussion
National Weather Service Huntsville AL
649 AM CDT Sat Oct 13 2018

For 12Z TAFS.


.NEAR TERM...(Today)
Issued at 357 AM CDT Sat Oct 13 2018

Temperatures across the area this morning currently range from the
mid/upper 50s to around 60 degrees, which is about 5-10 degrees 
warmer than this time yesterday. This is thanks to the cloud cover in
place across the region, associated with a cold front (draped SW to 
NE) meandering S/SEwrd through the CWFA. Regional METARs show this 
feature's passage, with N/NWrly winds picking up in its wake. High 
pressure at the sfc is building into the area from the NW, with weak
CAA ongoing as well. Time sections show these low clouds hanging 
around through most of the day today, and therefore high temps this 
afternoon will be a couple of degrees cooler than yesterday. Values 
should top out in the middle to upper 60s (with a few lower 60s 
possible in the higher terrain locations of Southern Middle TN). A 
dry day is expected, though clouds/moisture will increase through the
column overnight with a disturbance approaching the area in SW flow 
aloft (and the sfc ridge departing to the E helping to turn the winds
more SErly).

.SHORT TERM...(Tonight through Monday)
Issued at 357 AM CDT Sat Oct 13 2018

Much of the rainfall/lift with this approaching disturbance will
remain just N of the CWFA, though due to model guidance
differences/uncertainty in exact coverage, have opted to retain PoPs
beginning at 00Z tonight. PoPs increase through the night, but again,
they will be tapered higher N/lower S.

The disturbance moving through will stall a cold front just NW of the
area, with higher PoPs again N of the TN River and lessening as you 
move S across the CWFA. By this time as well, the subtropical ridge
strengthens over S FL, which places our area on the Nrn periphery of
the ridge. This pattern generally is a wetter one for our area
locally, with disturbances passing in SW flow aloft. The atmosphere
will recharge in-between disturbances, and bringing showers to the 
area through much of the week ahead. 

Daytime temps will fall through the day Monday with the cold front
stalled across the region, with morning lows Tuesday falling into the

.LONG TERM...(Monday night through Friday)
Issued at 357 AM CDT Sat Oct 13 2018

Much of the extended is a rinse-and-repeat forecast from what
occurred Monday. Disturbances in SW flow aloft will affect the area
on the Nrn periphery of the upper ridge to the SE. As such, rain is
in the forecast for Tuesday and Tuesday night, with a dry stretch for
Wednesday and Thursday in the wake of another cold front. High 
pressure builds into the area from the NW during this time and
quickly shifts to the E. This will help return flow to the SE,
increasing moisture ahead of our next weathermaker slated to arrive
late in the extended. 

Model runs continue to indicate heavy rainfall may affect the area
during late Friday night through the wee hours next Sunday. An upper
trof will swing across the Nrn CONUS, but runs into a strengthening
H5 ridge parked over S FL. With stout SW flow aloft and a disturbance
crossing the region, PWats are near/above the daily record max values
for this time frame (per the SPC PWat Climo page). I'm not sounding
the flooding alarms just yet, but this will be something to watch
unfold as the week progresses. Stay tuned!

Temps during the extended will be seasonable, and even a few degrees
below normal during this time. Considering normal highs this time of
year are in the mid/upper 70s, highs in the upper 60s to around 70
are a much-welcomed change from less than week ago when we were in
the 90s!


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 640 AM CDT Sat Oct 13 2018

Low clouds arnd 3-4kft will linger for much of the first half of the
TAF period, with showers in the vicinity of the terminals possible
by sunset this evening. Spotty -RA will overspread the region after
midnight, lingering thru the end of the TAF period. Conds aren't 
expected to drop below MVFR during this time, as rain will generally 
be light over both KMSL/KHSV. Heavier rain should remain N of both 
sites thru 14/12Z, but will increase in intensity after this time. 
Winds will slowly shift around to the SE, remaining AOB 10kts.





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