Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 240914

Area Forecast Discussion
National Weather Service Huntsville AL
314 AM CST Mon Feb 24 2020

.NEAR TERM...(Today)
Issued at 313 AM CST Mon Feb 24 2020

A shortwave trough and associated sfc low in the Southern Plains
will lift NE today and pull a cold front into the TN Valley by
tonight. Ahead of this front, SW flow will continue to pull moisture
into the region and isentropic lift increases. This will give way to
widespread showers and with weak elevated instability, some embedded
thunderstorms cannot be ruled out this afternoon into this evening.
Despite the overcast skies, WAA will help daytime highs reach the mid
to upper 50s. Rainfall totals may be 0.5-1.0" with locally heavier

.SHORT TERM...(Tonight through Wednesday night)
Issued at 313 AM CST Mon Feb 24 2020

As the shortwave trough lifts into the Great Lakes tonight, the sfc
low will slide more so into the OH Valley. A ~40kt LLJ will provide
one last push of moisture ahead of the front, getting dewpoints into
the lower 50s. As previously mentioned, a few embedded thunderstorms
are possible into the evening hours. Otherwise, showers are expected
to persist tonight and taper from west to east as the cold front
pushes into the TN Valley. Shower activity should be finished around
the morning commute/bus stop timeframe. Overnight lows tonight will
be mild, only falling into the upper 40s to lower 50s.

The cold air won`t quite hit us just yet as the daytime highs on
Tuesday could still reach the upper 50s to lower 60s with stout SW
flow aloft still in place. The break in the rain will be short lived
as another system is right on the heels of our last one. Showers will
return to the forecast by Tuesday night ahead of an amplifying and
deepening trough in the Southern Plains. Showers will be isolated to
scattered Wednesday morning ahead of a reinforcing front. The front
will push through Wednesday afternoon, and once again taper the
precip from west to east. Northwesterly winds of 10-15kts and gusts
15-20kts will filter in the colder air we were waiting for. Daytime
highs will be 10 degrees cooler than Tuesday, only reaching the upper
40s to lower 50s and the overnight lows will be chilly in the upper

.LONG TERM...(Thursday through Sunday)
Issued at 313 AM CST Mon Feb 24 2020

Northwesterly flow pattern sets up over the Tennessee Valley, with
cold air funneling in from the Northern Plains. This will lead to
cool, breezy conditions on Thursday until the post-frontal pressure
gradient relaxes Thursday afternoon/evening. A weak shortwave will
increase cloud cover on Friday, but with dry air in place and not
much moisture with the shortwave, expect no precipitation from this
weak disturbance.

Saturday, however, is another story. A weak surface low develops
associated with a stronger shortwave riding down the back-side of the
broad upper-level trough in place over the eastern half of the CONUS.
This surface low will help to advect moisture in from the Gulf of
Mexico just ahead of this disturbance, and with cold air in place
from the upper-level trough, this is an interesting scenario for
potential snowfall. Right now the GFS is likely a little bullish on
QPF for the dry air mass in place, and this is supported by GEFS
plumes for the HSV area on Saturday. However, the timing of
precipitation right now looks to move in after midnight Friday night
into Saturday morning, which is perfect timing for potential snowfall
with a cold air mass in place. My only concern would be potential
cloud cover helping to keep temperatures a bit warmer overnight, but
right now most models have lows Friday night dropping into the upper
20s across the Tennessee Valley. It`s too early to dig too far into
the details, but suffice to say there is definitely a chance for at
least a rain/snow mix, but more likely based on current models if
precip falls, it would start as snow, transition to a rain/snow mix,
then to all rain as the precip starts to move out of the area
Saturday evening.

Good news for those who hate cold weather on Sunday. The upper-level
trough finally ejects off the east coast and takes the cold air with
it. High pressure builds over the Southeast on Sunday, with
southwesterly flow developing on the west side of the High, which
will serve to really warm temperatures back up early next week.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1035 PM CST Sun Feb 23 2020

Ceilings at or above 060agl will lower at times by 10-11Z to ~025agl
with 3-5sm -SHRA (MVFR). By 14-15Z, ceilings will lower to
010-015agl with scattered to numerous SHRA. By 18-20Z, IFR and LIFR
conditions are expected with ceilings below 005agl with 2SM SHRA.
LLWS is expected by 20Z at KMSL and by 01Z at KHSV. Ceilings may
slowly climb above 010agl (MVFR) toward the end of the forecast





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