Area Forecast Discussion
Issued by NWS Birmingham, AL
FXUS64 KBMX 291138
Area Forecast Discussion
National Weather Service Birmingham AL
638 AM CDT FRI JUL 29 2016
For 12Z Aviation.
A weak upper trough remains in place across the region with most of
its influence across the northern half of Alabama. This feature
along with deep moisture and daytime heating should lead to a
continuation of above normal rain chances across the north and
central part of the forecast area. Westerlies aloft will result in
faster than typical storm motions for July, leading to relatively
higher coverage of measurable rainfall for today.
Saturday through Friday, precipitable water values remain around 2
inches the entire period with mean relative humidity values
generally 65 percent or higher. The model suite has been pretty
consistent and agreeable with the synoptic setup. The broad upper
ridge dominating the southern tier of the Conus will oscillate west
and east as a few disturbances in the westerlies move by well
north of the region. A few subtle, rather weak features move
overhead down south, but not any significant upper support. The
general weakness in the ridge will remain near central Alabama
much of the period providing conditions favorable for daily
Most convection will be diurnally driven or have some elements of
mesoscale or lower scales for development. Due to these factors,
will keep pops higher during the daytime hours but not completely
gone at night. Additionally, these pops will be at or above
climatology the entire period, especially in the daytime. Saturday
through Monday appear to have the best coverage due to the upper
weakness nearby. 500mb heights generally range from 588-593mb the
next week with low level thicknesses and temperatures slightly
high the next several days. But due to the cloud cover and rain
chances, expect highs in the low to mid 90s with surface dew
points hanging in the 70s. Heat indices will be in the 100 to 105
12Z TAF Discussion.
Occasional MVFR cigs could occur across the northern sites early
in the TAF period, but mainly VFR cigs are expected. Daytime
heating will aid in scattered showers developing beginning around
15Z. This activity will continue to intensify into thunderstorms
by 18Z with VCTS for the afternoon. Exact timing and placement is
unclear, but brief interruptions/impacts may occur especially
from KMGM northward.
Generally scattered showers and thunderstorms are expected over
the next several days with highs in the upper 80s and low/mid 90s.
Surface winds will be less than 10 mph and generally from the
southwest/west through the weekend. Since surface dew points are
so high, critical fire weather thresholds are not expected to be
met, with no watches or warnings anticipated.