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FXUS64 KBMX 191120

Area Forecast Discussion
National Weather Service Birmingham AL
620 AM CDT Sat Oct 19 2019

For 12Z Aviation.


/Updated at 0351 AM CDT Sat Oct 19 2019/

Today and Tonight.

Tropical Storm Nestor continues to move northeastward and is 
expected to make landfall this morning along the Florida Gulf
Coast near Mexico Beach. The system is asymmetrical with the 
stronger winds and most of the rain on the east side of the storm.
As Nestor moves through the Florida Panhandle and into Southern 
Georgia today, it is expected to transition to a post-tropical 

Overall, the impacts to Central AL from Tropical Storm Nestor look  
to be minimal. Winds today will be noticeably higher, especially 
this morning for areas south of I-85 (sustained 10-15 with gusts 
20mph+), but the strongest winds should remain to our south. By 
the afternoon, winds will decrease area-wide. Nestor has a current
forward speed of around 20mph, which will help keep any flooding 
threat to a minimum across Central AL as well. 

Timing has been fairly consistent the last few forecasts. Light
rain is already moving into the southeastern counties this 
morning. This is expected to spread northward through the morning,
with the best chances of rain being generally east of I-65. Rain 
will decrease west to east in the early afternoon and most of 
Central AL should be rain-free by 7-10pm tonight.

Temperatures today will be moderated by the expansive cloud cover 
and rainfall. Highs will range from the low 60s in the east, where  
there will be more rainfall, to the low 70s in the west. Lows 
tonight will drop into the low 50s. 


/Updated at 0351 AM CDT Sat Oct 19 2019/

Sunday through Saturday. 

Between weather systems, height rises will take place on Sunday as
a significant trough digs toward the Central Plains. A dry and warm
afternoon is expected under the influence of southerly flow. 
Temperatures should reach the upper 70s to the lower 80s. 

Pressure falls will take place Sunday night into Monday across the 
span of the Mississippi River Valley as a powerful jet carves out a 
deep trough centered over the Upper Midwest. A 40-50 kt low-level 
jet should be located along the MS River at 12Z Monday with upper
60s to near 70 degree dewpoints advecting northward across the 
ArkLaMiss. Most of our forecast area will remain dry through the 
early afternoon, but a band of showers and storms will move in 
from the west during the afternoon and evening. The low-level jet 
is expected to weaken into the 35-40 kt range as it moves into our
northwest counties. However, with SBCAPE of 500-1000 J/kg, there 
appears to be a marginal threat for isolated damaging winds and 
perhaps a brief tornado. 

The entrainment of a subtropical shortwave into the larger-scale 
trough may complicate the convective evolution for areas farther 
southeast. This feature may shift the strongest forcing and lift 
toward our southeastern counties, causing a localized minimum in 
the low-level jet and a lull in convection across the middle of 
the area. Additionally, the subtropical shortwave could cause a 
small-scale enhancement of the low level jet across our southeast 
counties Monday night. Therefore, the marginal risk for isolated 
damaging winds and a brief tornado will be expanded to cover all 
of our forecast area. Forecast confidence is low with this system,
but an upgrade to a slight risk may become necessary. 

Cooler and much drier air will move into the region on Tuesday 
behind a cold front with high pressure in control through early 
Thursday. Another large trough is expected to take shape Thursday 
night and Friday to our northwest, leading to the potential for 
widespread rain for Thursday night through Saturday. 



12Z TAF Discussion.

Tropical Storm Nestor will continue to move northeastward and will
lead to some messy weather for portions of Eastern and
Southeastern AL this morning and into the early afternoon. Expect
gradual decrease in CIGs to MVFR as the rain shield moves into 
Central AL. The strongest winds for our TAF sites will likely be 
at TOI and MGM in the the later morning hours. VIS could be 
reduced to MVFR or IFR temporarily during the heaviest rain at 
ANB, ASN, TOI, and MGM. We've already seen some reduction in VIS
at TOI as a band of rain passed over. I've tried to capture this
for TOI and MGM in TEMPO groups. Rain should begin to move out in
the early afternoon, but guidance hangs on to the low CIGs for 
the rest of the period. I'm not confident that CIGS will go to
IFR/LIFR with the departing tropical system, so I've kept lower 
MVFR conditions in the forecast. 




Tropical Storm Nestor will be responsible for bands of light to
moderate rain today especially across the eastern half of the 
area. Dry conditions will return for Sunday, but a cold front 
will bring showers and storms for Monday afternoon into Monday

The Alabama Forestry Commission continues to have a fire alert in
effect that includes all of Central Alabama. For more information
about restrictions, visit their web site at


Gadsden     64  50  78  59  80 /  60  10   0  10  50 
Anniston    63  51  79  61  80 /  70  20   0  10  40 
Birmingham  68  55  80  64  80 /  50  10   0  20  60 
Tuscaloosa  70  54  82  65  81 /  30  10   0  20  70 
Calera      68  53  80  63  80 /  50  10   0  10  50 
Auburn      64  53  79  61  80 /  80  10   0  10  30 
Montgomery  69  54  82  63  82 /  60  10   0  10  50 
Troy        68  53  81  61  83 /  80  10   0  10  40 



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