Scientific Forecaster Discussion
fxus64 kbmx 221155
Area forecast discussion
National Weather Service Birmingham Alabama
655 am CDT Thu Jun 22 2017
for 12z aviation.
today and tonight.
Currently watching several waves of rainfall moving through the
area the morning. Heaviest rains are along and north of I-22/I-20
and along I-65. Also watching the next band of rainfall developing
just south of Greenville and moving northward. There will be a
brief lull in the SW with only isolated to scattered showers as a
dry slot works into the area but that will go ahead by 7 am and
the area will fill back in. Thus will keep the Flash Flood Watch
for this area. Storm Prediction Center has also put the southern tier of counties in a
Tornado Watch as this band moves into the region. We have been
monitoring the over trends and see no reason to not agree with
this assessment. The main tornado threat for the day will be for
counties along and west of the I-65 corridor as the bands develop
and slide north through the area.
As we work into the evening hours we will see the bands begin to
diminish in size and intensity as most of the activity will shift
further west closer the center of Cindy. This may provide another
little lull in activity across much of Alabama through the night.
With that said though any banding that does develop could produce
locally heavy rains.
As we work into Friday, we will see the second stage of this
tropical system begin to impact the area. The low pressure system
itself will move into western Tennessee and then slide east
northeast and begin to merge with a cold front. As the low gets
closer to the area we will see an increase in showers and storms
once again, this time along and north of the I-20 corridor. We may
need to issue a new Flash Flood Watch as this system draws closer.
Despite that there will also be a threat for tornadoes with any
line that develops and moves through the area particularly in the
afternoon and into the evening hours.
By Saturday, Cindy will have merged with a cold front coming down
from the north and be well removed from the area. However, the
front, the continued moist air mass, and a lingering weakness in
the subtropical ridge will result in a continued wet pattern
through the weekend, with the potential for continued flooding
concerns. As is typical, the GFS is quicker with the progression
of the front than the European model (ecmwf) and will stick closer to the slower
solution. But by Monday/Monday night the cold front is expected to
pass through the area as a trough amplifies over the East Coast. A
second cold front will move through and provide a cool airmass for
this time of the year for the upcoming week.
12z taf discussion.
Going to be a wild next 24 hours for the taf sites. Sites will
likely bounce up and down between IFR and MVFR through the day as
bands of showers and low clouds move in and out of the areas. Will
be aggressive on tafs as far as IFR conditions go and only Chase
clearing lines once they become apparent and will remain that way.
Kept in the low level wind shear this morning at the northern sites and upper air
sounding confirmed the differences from the surface to the ground.
Went ahead and included ts at toi as a storm developed to the east
and will slide nearby. Otherwise went with rain showers and will amend to
add ts as it becomes more apparent as well.
Scattered to widespread showers and storms are expected through
the next several days with a moist airmass in place. The best
chance of rain will occur Thursday and Friday. A cold front will
then swing into the area for the weekend adding in more rain
chances through Sunday. Drier are will work into the area on
Monday and Tuesday. There are no fire weather concerns.
Preliminary point temps/pops...
Gadsden 78 72 85 72 84 / 100 70 70 80 60
Anniston 78 72 87 72 84 / 90 70 50 80 70
Birmingham 79 74 86 73 84 / 100 80 70 80 60
Tuscaloosa 81 74 86 73 84 / 100 80 80 80 60
Calera 79 73 86 73 84 / 100 80 60 80 70
Auburn 81 72 87 73 84 / 80 30 20 50 70
Montgomery 82 75 90 75 87 / 100 60 30 50 70
Troy 83 73 88 74 87 / 90 40 20 40 70
Flash Flood Watch through this evening for the following