Area Forecast Discussion
Issued by NWS Birmingham, AL
FXUS64 KBMX 292049
Area Forecast Discussion
National Weather Service Birmingham AL
349 PM CDT THU SEP 29 2016
Very pleasant fall conditions are upon most of Central Alabama, with
dry air and cooler temperatures. PWATS on the 12z KBMX sounding this
morning measured 0.75 inches, which is the lowest we`ve seen in
quite a long time. Cold air advection will continue through the
afternoon with strong northerly flow in place. Winds have been
gusting around 20 knots at times this afternoon, but will diminish
after sunset tonight. Due to the strong upper low just to our north,
mid-level clouds have developed on the west side of the low, moving
southward. We`ll see some of those clouds affect our northern
counties through the afternoon and into the evening. Scattered to
broken clouds can be expected for our northern counties, while
mostly clear skies are expected across the southern half of the CWA.
Temperatures will quickly drop after sunset with the dry air and
mostly clear skies in place.
Thursday night through Wednesday.
Tonight cold air advection will continue to dominate the forecast
area, keeping cooler temps and mostly clear skies around
throughout the night. Friday the 850mb low will retrograde, thus
changing the advection pattern from cold air to neutral. This
correlated with the 1000mb to 850mb thickness gradient and
continued dry air in the mid-levels, will allow afternoon temps
to rebound to at least mid 80s or higher. This weekend, the upper
low, currently over the Ohio river valley will begin to be pulled
north by the polar jet. This will keep a westerly winds aloft, as
well as the dry air around, which in turn will keep minimal cloud
cover through Wednesday. As the upper low moves north, so will
the 850mb low. This will increase warm air advection over the
Central AL. These combined variables mean increased temperatures
over the weekend and next week, but also lower chances of rain.
Currently projecting highs in the upper 80s. Lows will remain the
high 50s and low 60s until the warm air is able to win out over
the radiative cooling by Wednesday. The next frontal passage looks
to be the end of next week. However models diverge on the exact
timing and moisture availability with this system.
18Z TAF Discussion.
VFR conditions are expected through the forecast period. Only
impacts will be gusty northwest winds prevailing around 10-12
knots with gusts between 17-20 knots. Winds will diminish
overnight tonight, with perhaps some FEW to SCT mid-level clouds
moving in from the north.
Dry and cooler weather is expected through the next 7 days. No
fire weather concerns are anticipated.
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 51 79 53 81 53 / 0 0 0 0 0
Anniston 51 79 54 82 54 / 0 0 0 0 0
Birmingham 53 81 56 82 58 / 0 0 0 0 0
Tuscaloosa 53 82 54 84 57 / 0 0 0 0 0
Calera 53 82 55 83 58 / 0 0 0 0 0
Auburn 53 81 53 83 58 / 0 0 0 0 0
Montgomery 54 82 56 86 59 / 0 0 0 0 0
Troy 53 83 53 85 56 / 0 0 0 0 0