Special Weather Statement, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
1213 PM CDT Mon Jun 11 2018

.UPDATE...
For 18Z Aviation.

&&

.SHORT TERM...
Today and Tonight.

Leftover mid and upper level clouds remain across east Central
Alabama early this morning, with localized fog reducing visibilities
to below 1 mile at times. Fog will lift with sunrise. Clouds will
delay warming across the east, much like yesterday, but will likely
also provide differential heating boundaries and a focus for
convection by late morning.

Synoptically, a weak trough will be across the area today, while the
surface remains dominated by a ridge centered to our southeast.
Another day of afternoon showers and storms, mainly driven by
daytime heating and boundary collisions. Stronger storms could
produce strong wind gusts, and with PW values of 1.5-1.75 inches,
heavy downpours are expected.

Temperatures will be a degree or two cooler today, generally below
90F for the area. With increased moisture though, heat index values
will be in the low to mid 90s.

Will gradually decrease rain coverage tonight, but could see a
weakening MCV clip the area late tonight in weak northwesterly flow.
Lows will be in the upper 60s to lower 70s.

14

.LONG TERM...
Tuesday through Sunday.

A typical summertime pattern of scattered to at times numerous
showers/storms is expected this week with weak flow aloft and
little air mass change. Given the weak flow, model wind fields
aloft at the start of the period Tuesday morning are littered
with convectively generated perturbations which will impact the
forecast but have low predictability. Overall the Southeast will
be within a broad upper trough/weakness in the subtropical ridge,
with one ridge centered over New Mexico and one over the Atlantic.
Southern stream upper-level trough will remain over the Gulf with
upper lows over the western and eastern Gulf. Low-level flow will
be westerly due to low-level ridging over the northern Gulf,
resulting in good but not overly moist PWATs of 1.7-1.9 inches and
layer mean RH values around 70%. The result will be rain chances
a little bit above climatology. The stronger storms will be
capable of producing gusty winds, frequent lightning, and brief
heavy downpours. For Tuesday, best rain chances may be across
the southern counties where PWATs approach 2 inches, and in the
eastern counties in the vicinity of a weak backdoor cold front
moving into North Georgia. Will have to keep an eye out for any
stronger storms moving in from the NW Tuesday night, but currently
only the 12km and 3km NAMs show this. Will continue with the idea
that Wednesday will see the best rain coverage areawide as a weak
vorticity axis and axis of higher 500mb mixing ratios trailing
from a shortwave in the Mid-Atlantic will be present aloft, and
PWATs will be around 1.9 inches areawide.

500mb heights may rise slightly by Thursday as ridging amplifies
over the central CONUS behind a trough over New England. Best
rain chances may be in the south near the remnant moisture axis.
For Friday through the weekend, models have varied some between
each other and run to run regarding whether the upper-level ridge
or an amplifying trough/possible cutoff low over the western
Atlantic will win out. In general, though, expect continued
scattered showers and storms with northerly flow aloft and
temperatures a couple degrees above normal (low 90s vs. normal
upper 80s). If the trough wins out, a back door cold front may
approach the area, but not very confident in that happening.
Regarding the tropics, the GFS is finally trending towards the
other models with just a broad area of low pressure in the western
Gulf near an upper low, with a plume of deep tropical moisture
moving into Texas and little to no impact locally.

32/Davis

&&

.AVIATION...
18Z TAF Discussion.

Scattered showers and thunderstorms will continue through the
afternoon. Due to cloud cover and boundaries across the
area...only have a moderate confidence for thunderstorms to impact
KTCL...KMGM...and KTOI. Included a TEMPO for these sites...with a
VCTS elsewhere to account for the lower confidence in TS
coverage.

Fog development is again possible early Tuesday morning due to
low level moisture availability...especially in the areas that
receive thunderstorms this afternoon. Included IFR visibilities
at KTCL...KMGM...and KTOI though patchy dense fog is possible
areawide.

Scattered showers and thunderstorms are again possible Wednesday
afternoon.

24

&&

.FIRE WEATHER...

Scattered to numerous showers and storms expected each day
through the week. Cannot rule out at least isolated coverage
during the overnight hours. Light fog and/or low clouds is
possible each morning, and most likely will be near locations that
receive rainfall the previous day/evening. RH values remain well
above critical values. There are no fire weather concerns at this
time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     69  88  68  88  69 /  30  50  40  60  30
Anniston    69  88  68  88  69 /  30  60  40  60  30
Birmingham  71  89  71  89  71 /  20  50  40  60  30
Tuscaloosa  71  90  71  90  71 /  30  50  40  60  30
Calera      70  88  69  87  69 /  20  50  40  60  30
Auburn      70  86  69  86  69 /  30  60  40  60  40
Montgomery  71  88  70  89  71 /  30  60  40  60  40
Troy        70  87  70  88  70 /  30  60  40  60  40

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
821 AM CDT Mon Jun 11 2018

ALZ011>015-017>050-121630-
Marion-Lamar-Fayette-Winston-Walker-Blount-Etowah-Calhoun-Cherokee-
Cleburne-Pickens-Tuscaloosa-Jefferson-Shelby-St. Clair-Talladega-
Clay-Randolph-Sumter-Greene-Hale-Perry-Bibb-Chilton-Coosa-Tallapoosa-
Chambers-Marengo-Dallas-Autauga-Lowndes-Elmore-Montgomery-Macon-
Bullock-Lee-Russell-Pike-Barbour-
821 AM CDT Mon Jun 11 2018

This Hazardous Weather Outlook is for the counties served by the
National Weather Service office in Birmingham.

.DAY ONE...Outlook through Tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management is not
expected at this time.

Special Weather Statement
National Weather Service Birmingham AL
117 PM CDT MON JUN 11 2018

ALZ022-111900-
Pickens AL-
117 PM CDT MON JUN 11 2018

...SIGNIFICANT WEATHER ADVISORY FOR PICKENS COUNTY UNTIL 200 PM
CDT...

At 116 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Reform to Carrollton to near Garden.
Movement was east at 15 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Aliceville, Gordo, Reform, Carrollton, Pickensville, Ethelsville,
McMullen, Garden, Ashcraft Corner, Johnston Lake, Bevill Lock And
Dam, Gainesville Lake Campground, Dillburg, North Pickens Airport,
McShan, George Downer Airport, Owens, Kirk, Pioneer and Cochrane.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3340 8828 3347 8803 3353 8791 3353 8784
      3316 8784 3307 8809 3299 8834
TIME...MOT...LOC 1816Z 243DEG 14KT 3342 8797 3324 8810 3315 8822