Area Forecast Discussion
Issued by NWS Birmingham, AL

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

FXUS64 KBMX 262343

Area Forecast Discussion
National Weather Service Birmingham AL
643 PM CDT Wed Jun 26 2019

Evening Update and 00Z Aviation.



Radar mosaic suggests that the MCV has moved into western
Georgia, but an extensive arcing outflow boundary extends from
Cullman County to Lee County, serving as a source of lift for
continued thunderstorm development. PoPs have been adjusted to
account for this activity. It`s uncertain how much southward
progress this activity will have this evening as the MCV continues
to push eastward and the outflow boundary encounters a slightly
drier low-level air mass with decreased MLCAPE, and also
considering cell motions largely parallel to the outflow boundary
and a recent weakening trend. Large dew point depressions are
allowing for gusty winds as the outflow boundary moves through,
but DCAPE is limited by some mid-level moisture, limiting the
overall microburst potential.

A larger scale MCV is currently located over southeast MO.
Convection associated with this feature has a westerly component
of motion, and is not expected to impact the area overnight. By
tomorrow, however, the MCV continues to drift southward. Increased
PoPs a bit across the west tomorrow for this reason, and also due
to increased low-level convergence as easterly low-level flow
moves in as low-level ridging strengthens over VA/NC. Increased
DCAPE and mid-level lapse rates suggest some strong storms
tomorrow afternoon as well.


Previous short-term discussion:
This morning, the last push from an overnight MCV in Mississippi
brought light showers from Tuscaloosa to Birmingham. This activity
has come to an end with a layer of high stratus remaining over
the area. Highest rain chances this afternoon will be focused in
northeastern Alabama where outflow and remnant boundaries can be
viewed on visible satellite imagery supplemented by orographic
effects. With the high center positioned over southern Mississippi
per surface analysis, thunderstorms will generally progress north
to south this afternoon as winds become more north-northeasterly.
Kept slight pops in through midnight since activity has been
persistent into the early evening, but expect intensity to follow
seasonal trends and decrease shortly after sunset. Otherwise,
heating was slowed this morning by the cloud cover, but a few
breaks in the clouds have allowed temperatures to catch up and
warming is back on track. Therefore, no changes to the afternoon
highs were necessary in this update.


Thursday through Tuesday.

A cliche summer pattern will be in place across Central Alabama
into the long-term with jet stream activity retreating northward
toward the US/Canada border. Primary upper-level synoptic features
will include the persistent trough/upper-low near the Pacific
Northwest and a broad, longwave ridge across the eastern CONUS. A
weak upper- level trough near our area Thursday is expected to
cutoff from easterly flow and generally rotate westward along the
base of the ridge, with many mesoscale eddies/MCVs evident in
vorticity prognostics. It`s placement to our southwest and effects
from the ridge will promote little change in our tropical airmass
the next several days. As such, most days will feature afternoon
diurnally forced showers & thunderstorms as low-level
destabilization occurs, including sea breeze thunderstorms along
the Gulf Coast. Afternoon highs in the 80s/90s will continue, with
overnight lows generally falling to the 60s/70s as dewpoints
remain in that range. Though we`re bound to get a strong storm at
some point during this time, no obvious severe weather threat is
currently forecast.



00Z TAF Discussion.

Outflow boundary will continue to result in potential for TSRA
near BHM/EET for the next 1-3 hours. Will monitor for any
development as the boundary approaches MGM and will amend if
necessary. Overnight, will not mention any fog due to a lack of
significant rainfall at the terminals, and crossover temperatures
are not expected to be reached. Best chance of afternoon TSRA
appears to be near BHM and TCL Thursday afternoon due to an
approaching upper-level disturbance and low-level convergence.




Afternoon high temperatures will be at or slightly above normal
through the week. Minimum relative humidity values should remain
in the 40s-50s most areas but some areas in the southeast may drop
into the upper 30s Thursday afternoon. Rain chances appear on
most days and in most areas as afternoon showers and thunderstorms
are expected, but coverage should stay scattered or less.


Gadsden     67  91  66  90  67 /  20  30  10  20  20
Anniston    68  92  68  91  68 /  20  30  10  20  20
Birmingham  71  93  70  92  71 /  40  30  10  20  20
Tuscaloosa  71  94  70  92  71 /  20  40  10  20  20
Calera      69  92  68  90  68 /  40  30  10  20  20
Auburn      71  91  70  90  71 /  30  10  20  20  20
Montgomery  71  93  70  93  71 /  20  20  10  20  20
Troy        69  92  69  91  70 /  20  20  20  30  20




$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.