Scientific Forecaster Discussion
fxus64 kbmx 191200
Area forecast discussion
National Weather Service Birmingham Alabama
700 am CDT Mon Aug 19 2019
for 12z aviation.
/updated at 0356 am CDT Mon Aug 19 2019/
today and tonight.
This am we have mid and high cloudiness noted on satellite. Some of
this could stick with US today in conjunction with a weak upper
disturbance. However, we continue to be in a very warm humid low
level flow which will help US heat up. Afternoon convection is
expected today with heating and will be aided some by the shortwave
moving through the weak upper flow around the Texas upper ridge and
across central Alabama. However, with similar 1000-850 mb thickness
values expected today for portions of central Alabama in advance and
outside of convection, we could still heat up sufficiently to hit
heat advisory criteria. With the ongoing heat building over the last
few days, will go on the side of caution. With that said, will not
be issuing for the whole area, just for a band of higher heat values
from the west-northwest counties to around mgm including the bhm
Metro. Activity is expected to taper off by mid evening as we lose
heating and disturbance rotates through. Overnight temperatures
tonight should be similar to this morning.
/updated at 0356 am CDT Mon Aug 19 2019/
Tuesday through Sunday.
Much of the extended forecast remains on track for this update. On
Tuesday, high pressure sits over the eastern plains while a large
anticyclone remains over the western Atlantic. In between these two
circulations, a weak low-level inverted trough and low height center
will situate over portions of the southeast including southern
Georgia and the Florida Panhandle as southeasterly anticyclonic flow
aloft shifts the disturbance slowly westward over the forecast area
through Wednesday. This feature will provide support for afternoon
convection as we begin to see lower temperatures with highs
decreasing into the low to mid 90s, although higher humidity levels
will make it feel a bit warmer. The overall wind and height fields
become rather messy on Thursday with the aforementioned weak
troughing becoming much less defined, but with the Bermuda high
extending to our southeast, a few periods of southerly low-level
winds appear likely enough to continue fueling a moist airmass
such that scattered to numerous afternoon thunderstorms can be
expected during peak heating on Thursday and Friday.
Meanwhile, deep-layer troughing deepens over the eastern Continental U.S. By
the end of the week driving a cold front south through the Ohio and
Tennessee valleys. Uncertainty remains between model guidance on
whether the tail edge of the front will ultimately pass through the
forecast area this weekend, and confidence remains low on any one
given outcome. Therefore, the forecast for Saturday and Sunday, and
associated 50 to 60 percent pops, will be focused on the broad
cyclonic flow aloft over central Alabama as the base of the trough
moves through the southeast in conjunction with a rich axis of
moisture (pwats ~2 inches) ahead of the front. Periods of rain over
the next week will help keep US cooler during the daytime with
highs in the upper 80s to near 90f Saturday and Sunday as ridging
becomes less pronounced over the forecast area.
12z taf discussion.
We continue with mid and high level cloudiness noted on
satellite. This has helped early morning fog from being too big
of an issue. I do have a MVFR fog tempo mention in for toi as
they remain on the edge of the clouds. Afternoon diurnal convection
is anticipated for today and could last a couple of hours past
Rain chances begin increasing today with scattered to numerous
afternoon showers and thunderstorms possible most days this week.
Temperatures will gradually return to normal levels by mid week as
relative humidity values continue to rise.
Preliminary point temps/pops...
Gadsden 98 70 96 71 94 / 30 20 40 20 40
Anniston 96 71 95 72 94 / 40 30 40 30 40
Birmingham 99 73 97 74 96 / 30 20 40 30 40
Tuscaloosa 98 74 96 74 95 / 30 20 40 30 40
Calera 98 71 96 72 94 / 40 30 40 30 40
Auburn 94 72 91 72 91 / 50 40 50 30 50
Montgomery 97 73 95 73 94 / 50 40 50 30 50
Troy 94 71 92 71 92 / 60 40 60 30 50
heat advisory from noon today to 9 PM CDT this evening for the
following counties: Autauga...Bibb...Chilton...Dallas...