Scientific Forecaster Discussion
fxus64 kbmx 170457
Area forecast discussion
National Weather Service Birmingham Alabama
1057 PM CST Sat Nov 16 2019
for 06z aviation.
/updated at 0314 PM CST Sat Nov 16 2019/
The upper level low that brought rain and cloud cover to the area
Thursday and yesterday has rotated off the Georgia coast,
allowing for ridging to build across the lower Mississippi River
valley today. Winds have remained from the north today, with high
pressure over the Ohio River valley and low pressure to our
southeast. Despite the cool breezes, with sunny skies,
temperatures have warmed into the 60s this afternoon. Tonight,
with clear skies and light winds, lows will fall into the mid 30s
north to mid 40s southeast.
Looking toward the end of the forecast period, made changes to
rain chances in the Thursday/Friday timeframe to show a slower
approach of the system. However, there remains a large of amount
of disagreement in model solutions on how quickly the front moves
through the area. Expect adjustments in this timeframe over the
/updated at 0219 am CST Sat Nov 16 2019/
Sunday through Friday.
A potent narrow-wavelength/high-amplitude trough and associated
weak cold front will move into the area from the central Continental U.S. On
Sunday, causing the slow-moving mid-latitude cyclone off the
Carolina coast to take a northward turn. The low and mid-level air
mass over central Alabama will remain very dry, however, and only
increased cirrus is expected. A developing westerly component to
the flow should bump up temperatures into the 60s. The high clouds
and a somewhat enhanced pressure gradient should keep
temperatures on Sunday night a bit milder. A shot of cooler air
moves in behind the upper trough/cold front for Monday, while
another shortwave rotating around the base of the trough will
bring some additional mid/high-level clouds. A clipper system
moves through late Monday night/Tuesday morning. Decent moisture
will be present at 700mb but lift appears to be weak, with better
low-level moisture lagging behind the mid-level moisture.
Therefore will keep pops at around 10 percent during this period,
but would not be surprised at all to see some sprinkles during
this time frame.
Ridging aloft develops for Wednesday and Thursday as the eastern
Continental U.S. Trough lifts off to the northeast, and a digging trough
along the West Coast causes a cutoff low off the Baja Coast to
eject northeastward and begin to shear out, while a new cutoff
low forms over Southern California. This will allow temperatures
to rise into the upper 60s to lower 70s. Another cold front will
move in by the end of the week, and this time there will be enough
moisture for rain to develop. There remains some timing
differences amongst the guidance regarding the interaction of wave
associated with the baja cutoff low and a northern stream trough
digging into the upper Midwest. Instability continues to look
negligible at this time and will continue to leave out a mention
of thunder, though some weak instability could develop if the
slower solutions pan out.
06z taf discussion.
The strong upper low off the East Coast was pushing moisture back
to the west. This was a bit more than originally anticipated.
Added mention of some sct030-sct045 for all locations except tcl.
There may be a few patches where bkn occurs, but the majority of
cloud cover should remain VFR. Central Alabama will have a short
wave ridge move nearby on Sunday morning, allowing high level
cloudiness to increase. Winds will be calm to light northeast
overnight and eventually become west to southwest around 5kts by
Dry conditions continue through much of the upcoming week with
relative humidity values above 40 percent each afternoon. Winds will
be rather light through the period. The next chance of rain comes
in the Thursday/Friday timeframe.
Preliminary point temps/pops...
Gadsden 30 60 35 56 36 / 0 0 0 0 10
Anniston 33 62 37 58 37 / 0 0 0 0 10
Birmingham 33 61 38 57 39 / 0 0 0 0 10
Tuscaloosa 32 63 38 59 39 / 0 0 0 0 10
Calera 34 62 37 58 39 / 0 0 0 0 10
Auburn 37 61 40 60 39 / 0 0 0 0 10
Montgomery 37 66 39 62 40 / 0 0 0 0 10
Troy 37 64 39 61 39 / 0 0 0 0 10