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Area forecast discussion 
National Weather Service Birmingham Alabama
531 PM CST Friday Dec 26 2014

Update...
for 00z aviation.

&&

Discussion...

Cloud cover will continue to increase tonight...as the airmass
moistens. A few speckles on the radar this afternoon but doubtful
anything is reaching the ground at this point. Clouds and boundary
layer winds will play a role tonight and should be enough to keep
everyone above freezing. Temperatures in the middle 30s northeast to
middle 40s west tonight. As the longwave trough shifts eastward
across the plains...impulses rotating through the trough will
increase rain chances for central Alabama. The first of these will
approach the area Saturday morning. With dry lower levels...expect
rainfall to hold off until after sunrise tomorrow...and mostly
likely closer to late morning...for most of the area. Will keep a
slight chance of rain in the far west prior to sunrise. With
continued moist southwesterly flow and the added lift associated
with the impulses...the weekend continues to look wet with one to
two inches rainfall accumulation possible Saturday through Sunday
night. Highest rainfall totals will be over the west and north
where convergence will be best near a surface front. Because
rainfall is falling over a couple days...areal and flash flooding
is not expected to be a problem. However...a slight bump in the
rivers will be possible with some very minor overflow not out of
the question along the upper Tombigbee. Will continue to mention
isolated thunder but there is no severe threat.

The front will slowly push through the area...clearing central
Alabama on Monday as one shortwave pulls to the east and another
drops southward from the Pacific northwest region to re- enforce
the longwave trough. Behind the exiting cold front...a piece of
Arctic high pressure will slide southward down the plains. A secondary
push of cold air on Wednesday will drop temperatures below normal for
late December...about 5 to 10 degrees in the day and 3 to 6
overnight.

The longwave trough closes off an upper low over Southern
California Wednesday...which slowly tracks eastward and opens over
the Southern Plains late in the week. Widespread rain is expected
to return late in the week...mostly likely Friday. Although a
cold rain is expected before warmer air spreads northward ahead of
the surface low...at this time the airmass will be too warm for
any frozen precipitation. At least part of next weekend looks wet as
well.

88



&&

Aviation...
00z taf discussion.

VFR conditions currently across the terminals with a few light
sprinkles showing up on radar across northwest Alabama. Light
showers will be near ktcl for much of the overnight period but
heavier precipitation does not push into the terminals until after
18z. Ceilings will lower throughout the taf cycle as moisture
increases with MVFR conditions near the end of the taf cycle.
Timing of rain and lower ceilings will be refined in further taf
issuances.

05/Massachusetts

&&

Bmx watches/warnings/advisories...
none.

&&

$$

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