698 
FXUS64 KBMX 080527
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
1227 AM CDT Sat Sep 8 2018

.UPDATE...
For 06Z Aviation.

&&

.SHORT TERM...

A few showers remain on the radar scope early this evening. This
activity was confined to our northeast quadrant where a relative
maximum in mean relative humidity existed along with some light
orographic lift. This activity may go on for a few hours and may
also produce a brief lightning strike, but removed any mention 
after 06z. All else looked at track for the remainder of the 
evening and overnight.

75

Previous short-term discussion:Through Tonight.

Weak ridging and drier air across the area has kept shower and
thunderstorm activity to a minimum today. Cannot rule out a 
localized stronger wind gust, but chances are low. With less rain 
and cloud coverage, temperatures have warmed into the lower 90s at
most locations. Heat index values are around 100F. 

For this evening and overnight, showers across most of the area 
will diminish quickly with sunset. Will leave a 15-20% chance of 
a shower or storm in the far northeast, as weak upsloping could 
maintain a few showers after the loss of daytime heating. 
Temperatures slowly cool into the mid to upper 70s by 10pm, with 
overnight lows falling into the upper 60s to lower 70s. 

14

.LONG TERM...

Saturday and Sunday.

For the weekend, a transition to southerly/southwesterly flow ahead 
of an approaching mid/upper-level trough in the Plains will 
signal an increase in our precip activity. This especially picks 
up on Sunday. The driest air should be in place on Saturday as 
easterly flow behind Gordon helped to clear things out with PWs 
decreasing to ~1.6-1.7". PoPs have been adjusted to account for 
the expected increase in isolated to scattered thunderstorms 
during peak afternoon heating and destabilization. An area of low 
pressure, associated with the remnants of Gordon, should be 
developing near the confluence of the Ohio and Mississippi Rivers 
and move generally northeastward towards the eastern Great Lakes 
and move a trailing surface frontal boundary towards our 
northwestern CWA by Sunday. This will provide additional lift for 
convective development and have increased PoPs to 60/70% as PWs 
look to be on the increase to ~2.0-2.1" along this area. Lingering
pockets of drier air in the lower troposphere could help keep 
parts in the south and southeast drier, though it's hard to 
specific on this currently. High temperatures for the weekend will
range in our typical upper 80s to lower 90s with a decrease on 
Sunday from resultant cloud cover/precip activity, especially in 
our northwest counties.

Monday through Friday.

For the upcoming work week, expecting the forward movement of the 
frontal boundary to stall out across the area in the Monday/Tuesday 
time frame. There's not a lot of confidence on how far east the 
frontal boundary moves into the southeast CONUS before this happens 
as trends in guidance has been back-and-forth the past couple of 
days. Looking at mesoanalysis reveals the upper levels in a split-
flow configuration across the northern tier of the country. This is 
expected to continue before negative height anomalies from a 
significant trough builds across the Pacific northwest by mid/late 
next week. This in turn allows the Polar jet to move farther 
northward in to Canada for the east, removing our rain-making 
frontal boundary from its easterly progression. General thinking is 
for daily chances of scattered to numerous showers and thunderstorms 
for Monday/Tuesday in association with height falls and the 
approaching frontal boundary, with decreased chances later in the 
week as forcing becomes weaker/more diffuse. With abundant 
surface/boundary layer moisture in place & weak flow aloft, 
scattered thunderstorms from diurnal destabilization is expected for 
much of the week as the warm & moist airmass stays in place across 
our forecast area.

40/Sizemore


&&

.AVIATION...
06Z TAF Discussion.

After a brief touch of IFR vis at TOI and MGM this morning, it
will be a typical summer day with just isolated showers/storms 
during the afternoon. Best chances will be in the northeast, so 
included VCTS after 21Z for BHM, EET, ANB, and ASN. Will need to
monitor the seabreeze an the afternoon as it may reach MGM and TOI
after 00Z. Not enough confidence here to throw in anything more
than bkn050 cigs. 

16

&&

.FIRE WEATHER... 

The weather pattern continues to transition today, with low level
flow becoming more southerly to southwesterly. More typical 
isolated to scattered rain coverage is expected this afternoon, 
during peak heating. A front will approach the area from the 
northwest Sunday, increasing the chance of rain for the beginning 
of next week, as the front attempts to push southward through the 
area. Minimum RH values remain high through the period. Only
isolated locals of fog this morning. ow level moisture increases 
early next week, fog and/or low clouds could become a concern each
morning. 

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     90  69  89  69  85 /  30  20  50  50  70 
Anniston    90  70  89  69  87 /  30  20  40  40  70 
Birmingham  92  72  89  71  86 /  30  20  50  40  70 
Tuscaloosa  92  72  90  72  84 /  30  20  50  50  70 
Calera      90  70  87  70  84 /  30  20  40  40  70 
Auburn      88  70  87  70  85 /  30  20  50  30  50 
Montgomery  91  72  89  71  87 /  30  20  40  30  50 
Troy        89  70  89  70  87 /  40  20  40  20  50 

&&

.BMX WATCHES/WARNINGS/ADVISORIES/...
None. 

&&

$$