Area Forecast Discussion
Issued by NWS Birmingham, AL

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FXUS64 KBMX 251141

Area Forecast Discussion
National Weather Service Birmingham AL
641 AM CDT Wed Apr 25 2018

For 12Z Aviation.


Today and Tonight.

Currently this AM, a surface low is situated over NC. Our upper low
is lagging just a little behind that to the W over E TN/W NC. We
only have some lingering stratus in the northern half of AL still
attributed from this system. With the upper system moved off to the
E finally, we should be able to have a short break from any light
rain showers during the day today. Our next frontal system is still
off to the NW. However, we don`t get any good low level onshore
southerly flow ahead of its arrival. We keep dew points in the 50s
which should help keep our instability down some. This surface front
is expected to push toward the Mississippi River Valley today and
across MS toward W AL tonight. So our rain break will be short with
rain chances increasing from W to E with the best chances along and
west of I65/59 after midnight for some rain showers mainly, but a
few thunderstorms in the far W toward daybreak closer to the front
are possible. The best instability should hold off until during the


Thursday through Wednesday.

A highly amplified pattern will persist through the rest of this
week and into the early part of next week. A deep trough is over the
Eastern US Thursday and Friday.  A shortwave moves through the base
of the trough Thursday, sparking a weak surface low development that
will push through Central AL during the day Thursday. Modest
instability could make its way into the area ahead of the cold front
that is associated with the surface low; however, I expect the
forcing to remain relatively weak, limiting any severe potential.
Will maintain mention for slight chance of thunder with the rainfall
on Thursday, but will not introduce any severe wording in the HWO at
this time.

The surface low and associated cold front will slide off to our east
fairly quickly, and by Friday morning, rain chances across Central
AL look limited as dry air moves in behind the departing low.
Surface high pressure builds in over the weekend as an upper level
ridge slides over the eastern half of the CONUS. This will in a
warming trend for our afternoon highs over the weekend with mostly
clear skies.

The first half of the next week looks to follow a similar trend as
the weekend. Synoptic scale ridging persists over the Eastern CONUS
as a trough digs into the Pacific NW and into the Great Basin by
Monday evening. The high pressure over the Southeast US blocks the
trough to our west through at least mid-week, resulting in warm and
dry weather.



12Z TAF Discussion.

IFR cigs invading in from the north this morning, but not a solid
swath of stratus on satellite. Southern extent right now is
between 1A9 (BKN008 at Prattville) and SKC MGM. Current thinking
is that stratus would make it to MGM. I`m not as confident for
TOI. ASN and TCL are in clear holes but should fill in for a
couple of hours. With mixing expecting cigs to go to MVFR between
14-16z and VFR by 18-19z. Low cigs and rain come back from the
west tonight ahead of a front late. Most should hold off though
until after 12z. Mentioning SHRA at TCL first at 6z with VCSH at
BHM/EET later.

Note: ASN winds have been unreliable freezing up saying calm when
there is wind in the area. Airport is aware of issue. Have AMD
NOT SKED in TAF for the winds. Will amend for other elements.




A break in rain chances will occur during the day today. A cold
front moving through late Wednesday night and Thursday will then
bring wetting rains. Afternoon minimum relative humidity values
will remain above 50 percent through Thursday. There are no fire
weather concerns at this time.


Gadsden     70  52  64  48  70 /  10  50  80  20  10
Anniston    70  52  66  49  72 /  10  30  80  20  10
Birmingham  71  55  66  50  72 /   0  50  80  10  10
Tuscaloosa  76  57  68  50  72 /   0  80  80  10  10
Calera      72  55  67  49  71 /   0  50  80  10  10
Auburn      72  54  70  51  71 /   0  10  80  20  10
Montgomery  76  55  71  51  73 /   0  20  80  10  10
Troy        76  56  73  52  73 /   0  10  80  10  10





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