FXUS64 KBMX 202011
Area Forecast Discussion
National Weather Service Birmingham AL
311 PM CDT Fri Oct 20 2017
This afternoon and Tonight.
An upper ridge over the central Gulf Coast region has held at bay
deeper moisture west of the Mississippi River. Cirrus will be the
only cloud type to impact the area overnight. A strong inversion
aloft and increasing southeast flow overnight will result in
warmer temperatures tonight, with lows mainly in the lower to
middle 50s. Some of the colder valley locations across east and
northeast Alabama will likely fall into the middle and upper 40s.
Saturday through Thursday.
A ridge aloft and at the surface will continue to move eastward
on Saturday ahead of an approaching Plains trough. A warm and dry
day is expected since the western edge of the ridge should extend
far enough west to divert enhanced moisture and associated rain
chances to our west.
This will begin to change on Sunday as height falls overspread the
region. The GFS has trended toward the slower timing of the ECMWF,
and this scenario would lead to rain holding off for much of the
area (especially east of I-65) on Sunday afternoon. A widespread
soaking rainfall is likely Sunday night into Monday with both
models indicating a somewhat slow-moving closed upper trough
affecting the region. A moderate to strong low-level jet may be
present which could result in a non-zero threat for embedded QLCS
tornadoes. However, the setup does not appear to be favorable at
this time to due to very weak CAPE values in association with poor
lapse rates. An upstream disturbance will cause the trough to
become an open wave and accelerate eastward Monday night, putting
an end to the rainfall. Much cooler conditions are expected for
Tuesday through Thursday as the coolest airmass of the season
becomes established across the eastern CONUS.
18Z TAF Discussion.
VFR conds thru the period with only sct-bkn cirrus. Light east to
northeast winds becoming calm by 00z.
Mild and dry weather will continue through Saturday and early
Sunday. Widespread soaking rainfall is expected Sunday night into
Monday. Relative humidity values should remain above critical
thresholds. There are no fire weather concerns.
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 49 78 57 79 64 / 0 0 0 10 70
Anniston 52 78 59 79 66 / 0 0 0 10 60
Birmingham 55 80 63 80 67 / 0 0 10 20 80
Tuscaloosa 56 82 64 81 66 / 0 0 10 50 80
Calera 54 80 63 80 66 / 0 0 10 20 80
Auburn 56 79 62 79 68 / 0 0 10 10 60
Montgomery 57 83 64 84 69 / 0 0 10 20 80
Troy 57 82 63 82 68 / 0 0 10 20 70
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