Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Birmingham Alabama
556 PM CST Wed Dec 7 2016
for 00z aviation.
through Friday night.
As a result of saturated low levels, stratus has remained across
much of the area today. These clouds have kept afternoon temperatures
in the upper 40s to lower 50s. Temperatures will cool into the mid
30s north to lower 40s south tonight, ahead of an approaching
moisture-starved front. This front will push into central Alabama
early Thursday morning. Not much more than a band of mid level
moisture will accompany the front, and will maintain low rain
After days of cloud cover, the good news is the clouds should
finally move out of the area tomorrow afternoon as much drier air
advects southward behind the front. Surface winds will increase
behind the front with speeds in the 10-15 mph range. As a strong
surface ridge drops into the eastern Continental U.S. From central Canada, the
coldest air mass of the season will invade Alabama. Overnight lows
Thursday night in the 20s and brisk winds will result in wind chills
in the teens Friday morning for most of the area.
Temperatures should warm above freezing by mid to late morning, with
afternoon highs in the upper 30s to upper 40s. Friday will be the
coldest day of the forecast period. Overnight Friday, with the
surface high settling over the Tennessee Valley, lows once again
will be in the 20s Saturday morning, and would not be surprised to
see upper teens across the far north.
Saturday through Tuesday.
Temperatures moderate Saturday afternoon and Sunday as low level
winds veer to the southeast and south ahead of the next front.
Models show broad troughing across much of the Continental U.S. Early next
week, with a shortwave dropping across the Ohio River valley.
There is a large discrepancy in strength and timing of the
shortwave, and location and track of a developing surface low.
Both of which would have a great impact on when rain chances
return to the area. Will maintain rain chances returning Sunday
night and exiting Monday afternoon for now.
00z taf discussion.
A large area of stratus and stratocumulus remain across central
Alabama this evening. These ceilings are MVFR around 025. From
07z-14z, these ceilings will slowly dissipate and be replaced with
higher moisture from 050-070. A few of the locations may actually
experience ceilings lower somewhat between 00-06z before rising.
At any rate, MVFR ceilings expected with all terminals VFR between
Another cold front/trough will swing through coincident with the
clouds changing. This boundary will be the leading edge of much
cooler and drier air and it will infiltrate the area the remainder of
the period. The lower layers of the atmosphere will eventually dry
out and ceilings will rise to only cirrus by around 18z. Winds
start off northwest around 4-6kt. After 16-17z, winds become
northerly and gusty, with some gusts reaching 20-22kts.
A strong cold front will push through central Alabama on
Thursday. The air mass will be too dry for any appreciable
rainfall with the frontal passage. Much colder air will move into
the area Thursday through Saturday. Relative humidity values will drop below 25
percent Saturday afternoon for portions of the area for several
hours. However, winds will be light. Moisture begins to increase
Saturday night with rain chances returning Sunday and Monday.
Preliminary point temps/pops...
Gadsden 36 46 22 41 19 / 20 20 10 0 0
Anniston 38 47 23 42 22 / 10 20 10 0 0
Birmingham 38 46 24 42 23 / 10 20 10 0 0
Tuscaloosa 39 48 24 43 21 / 20 20 10 0 0
Calera 39 48 25 43 22 / 10 20 10 0 0
Auburn 42 52 26 44 25 / 0 20 10 0 0
Montgomery 42 54 27 46 23 / 10 20 10 0 0
Troy 41 54 27 46 21 / 0 10 10 0 0