Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Birmingham Alabama
1250 PM CDT sun may 28 2017
for 18z aviation.
The outflow boundary that was generated by the storms overnight
has made into the southern counties this morning and is now
generally south of the I-85 corridor. Behind it we have a meso
high that has developed and will keep most of the area
precipitation free for the good portion of the afternoon. Can't
rule out an isolated shower/storm anywhere as we will do remain
Will continue to mention the some threat of strong to severe
thunderstorms for the northern two thirds of the central Alabama.
The timing will generally be after 7pm but more likely even later
than that. This threat would last into the overnight hours
especially with any impulse or mesoscale boundary from upstream.
The main threats will be damaging wind gusts and some hail.
Numerous showers and thunderstorms are expected for Memorial Day
in the southwest to northeast oriented moisture axis along and
south of the front which will have stalled. These will be aided by
weak shortwaves in the southwest flow aloft to the south of the
strong upper low over the Great Lakes. Strong storms will continue
to be possible, and an isolated severe storm cannot be ruled out.
0-6 km bulk shear values will be marginal at 25-35 kts, mid-
level lapse rates will be weakening, and profiles will be
fairly saturated. Ongoing precipitation may also hamper
destabilization. Therefore, chances of an organized threat are too
low to mention in the severe weather potential statement at this time.
The forecast area will remain in the moisture axis south of the
old front Tuesday and Wednesday with continued cyclonic upper-
level flow south of the upper low lifting into Ontario. Scattered
showers and storms will continue across the area, with the best
chances around peak heating. For the rest of the week, the upper
low will continue to lift northeastward while ridging develops
over the plains. A few southern stream waves will try to under-cut
the ridge. A warm and humid air mass will remain in place over
central Alabama, with continued summertime afternoon scattered
showers and thunderstorms.
18z taf discussion.
Overall a very low confident forecast after 9 hours. With that
said the first 9 hours should be VFR with only an isolated
shower possible. The boundary just passed through toi with a
thunderstorm developing just southeast of the area and moving
away. With the rains from overnight do not expect anything through
at least 00z and possibly 03z to develop or move into the area. We
are beginning to see some thunderstorms west of the MS river that
will likely make it into the area late evening into the overnight
hours. However models are having a very difficult time handling
these scenarios, thus reducing confidence.
Rainfall coverage may increase again this evening. Scattered
showers and storms will be possible each day. Critical fire
weather conditions are not expected due to abundant low level