Special Weather Statement, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
117 PM CDT Sat Jul 7 2018

.UPDATE...
Aviation and Short Term Afternoon Update.

&&

.SHORT TERM...

Showers with a few thunderstorms have developed across portions of
our eastern counties with heavier activity south and southeast of
our county warning area (CWA). Surface analyses show a weal cold
front from central Mississippi that extends northeast into
northern Georgia while a stationary boundary resides just south of
our CWA and is acting as a focus for heavier convection across
that area. A remnant MCV was identified over west-central Alabama
on visible satellite this morning and it is slowly migrating west.
This feature may help enhance convection later this afternoon to
our west.

Expect shower and thunderstorm activity to gradually expand and
move west through the afternoon. Have updated grids with higher
PoPs east then expanding west through early evening. The BMX 12Z
sounding contained a bit more moisture compared to yesterday so
the wet microburst risk today is low but greater wet microburst
potential will exist across our southern counties with model data
indicating slightly more dry air aloft. The modified sounding
contains around 3,000 J/kg of surface-based convective available
potential energy (CAPE) so we can not rule out a few strong
thunderstorms due to robust potential updraft strength. The
combination of precipitable water (PWAT) values near 1.80 inches,
greater than yesterday, along with relatively slow storm motions
will again pose a risk of localized flooding where locations
experience multiple rounds of convection or where convection
backbuilds to the east upwind of the mean flow aloft. This risk
will be especially impactful in urbanized and low-lying poor
drainage areas.

After sunset the instability will begin to wane in the lower
levels and convection is expected to gradually decrease in
coverage and intensity overnight while cloud cover will be slow to
erode over the area through the remainder of the evening.

05

.LONG TERM...
Sunday through Friday.

With still no sign of a suppressive upper-level ridge taking hold
across the Deep South, the convectively-active weather pattern
should continue for several more days.

A weak low-level convergence zone may persist on Sunday across
the forecast area as surface high pressure noses southwestward on
the eastern side of the Southern Appalachians, while a very weak
warm front moves northward from near the Gulf Coast. Showers and
storms could become numerous once again due to the residual
convergence zone and perhaps the northward advancement of
thunderstorms generated along the sea-breeze in the Florida
Panhandle as deep-layer flow turns more southerly.

For Monday the remnant convergence zone should be quite diffuse,
but a zone of high PWAT values from NW to SE across the CWA
should lead to higher than normal rain chances. This axis of
enhanced moisture may pivot to a north-south orientation on
Tuesday, and some slightly drier air could circulate around an
upper-level ridge and affect East Alabama. Forecast POPs currently
range from 40 to 60 percent from East to West on Tuesday.

For Wednesday through Friday, mid to upper-level flow is forecast
to become north to northeasterly around the eastern side of a
ridge. This could allow some drier air to affect at least the
northwestern part of the forecast area, and higher rain chances
(30-50 percent) may be focused along and south of Interstate 20.

87/Grantham

&&

.AVIATION...
18Z TAF Discussion.

Mainly diurnally driven showers and thunderstorms are just
initiating at 18z. There were several boundaries across Central
Alabama acting as foci for development. Due to the lower clouds this
morning, this development was delayed somewhat and have started the
terminals with VCSH. After 20-21z, added VCTS and TEMPO TS for all
sites through 00-01z. There may be some lingering activity after
this point in time, but decided not to mention anything at this time
due to chances lowering.

Boundary layer winds remain east to southeast overnight. There may
be some variability early due to a few fronts and outflows around.
The low level moisture remains high and chances are good that most
locations receive measurable rain today. Therefore, more low clouds
and patchy fog are possible late tonight. Added some IFR ceilings
near daybreak.

With moisture values very high today, some torrential rain is
possible along with gusty winds around 30 mph in the stronger storms.
Winds will be easterly at most spots at 6-8kts, lighter overnight.

75

&&

.FIRE WEATHER...

Enhanced rain chances are expected through Tuesday as a weak
front stalls across the region. Localized fog will be possible
each morning where rainfall occurs during the previous afternoon
and evening. There are no fire weather concerns at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     69  87  70  88  70 /  60  40  30  40  10
Anniston    70  86  70  87  70 /  70  50  30  40  10
Birmingham  71  87  72  89  72 /  60  60  40  40  10
Tuscaloosa  73  89  73  91  74 /  60  60  40  40  10
Calera      70  87  71  88  71 /  60  60  40  40  10
Auburn      70  84  71  86  71 /  70  60  40  40  10
Montgomery  72  89  73  90  73 /  70  60  40  40  10
Troy        71  88  72  89  72 /  70  70  40  40  10

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
503 AM CDT Sat Jul 7 2018

ALZ011>015-017>050-081315-
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-
503 AM CDT Sat Jul 7 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...Sunday through Friday.

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
121 PM CDT SAT JUL 7 2018

ALZ049-050-071845-
Pike AL-Barbour AL-
121 PM CDT SAT JUL 7 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN PIKE AND
SOUTHWESTERN BARBOUR COUNTIES UNTIL 145 PM CDT...

At 120 PM CDT, Doppler radar was tracking a strong thunderstorm over
Doster, or near Clio, moving west at 15 mph.

Pea size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Brundidge, Clio, Doster, Tennille, Hamilton Crossroads and Tarentum.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3174 8585 3167 8554 3162 8557 3162 8590
TIME...MOT...LOC 1820Z 103DEG 12KT 3163 8568

05