Special Weather Statement, NWS Birmingham, AL

Area Forecast Discussion...UPDATED
National Weather Service Birmingham AL
120 PM CDT THU JUL 14 2016

.UPDATE...
For 18Z Aviation.

&&

.MESOSCALE DISCUSSION...

1213 PM:
Convective complex has become outflow dominant over the past two
hours with isolated thunderstorms developing along the outflow
which currently extends just east of Corinth, MS southwest to near
Grenada in north-central Mississippi. The outflow boundary has
increased in forward motion, moving southeast near 30 mph.

Additional convective development is expected as the atmosphere
continues to become more unstable across our northwest counties as
temperatures rise into upper 80's with dew points in the mid 70's.

Modified soundings along with mesoanalysis data suggests CAPE
values in excess of 2500 J/kg with surface-based LI's between -8
and -10.

Primary concerns remain for wet microbursts and localized flooding
due to heavy downpours. Thunderstorms will also contain frequent
lightning activity.

Expect our northwest counties to experience an increase in
convective activity over the next two to three hours.

Isolated shower and thunderstorm activity is increasing across
our southwest counties of Sumter, Greene, Hale, Marengo, Perry and
Bibb Counties. This activity is moving slowly southeast and may
pose a localized flooding threat due to slow storm movement.

05

&&

.AVIATION...
18Z TAF Discussion.

Two areas of concern this afternoon. The first is from a line of
TSTM approaching from the northwest, with outflow boundaries,
downburst winds, some large hail, and heavy rain at times with the
stronger cells possible especially across the northwest sections of
the state. Will be monitoring these storms as they progress
southeast today. Our second area of concern will just be for
activity developing during the afternoon and moving up from the
south. Have tried to time these threats appropriately in the TAFs.
We should have a lull in the late evening and possible some
development or another complex late bringing more activity. There
is some uncertainty for this late night complex and have not
mentioned VCTS again until Friday morning when better chances are
expected.

08

&&

.FIRE WEATHER...

Periods of scattered showers and thunderstorms will continue
through the end of the week and into Saturday, with the highest
chances mainly in the afternoon. No critical fire weather concerns
with humid conditions persisting.

&&

.PREV DISCUSSION...
/Issued 402 AM CDT THU JUL 14 2016/

A small shift to the flow pattern over Central Alabama will occur
today as the weak mid-level shortwave trough which has been
located over Mississippi and West Alabama gradually sinks
southward. This will place most of Central Alabama into more of a
northwesterly to northerly mid-level flow pattern, which as is
typical adds a few more wrinkles to the summertime convection
forecast. For the first 24 hours, models seem to agree on the
general trend but show variability in timing, as is typical due to
the uncertainties of upstream convection. Currently keeping an
eye on two different MCSs located upstream, one over southern
Missouri and one over southeast Oklahoma, moving southeastward
along the periphery of a flat upper-level ridge extending from
the Southern Plains westward to the Desert Southwest. A few other
scattered showers and isolated thunderstorms have been present
ahead of this activity.

High-res guidance suggests that some remnants of this activity,
or new activity generated by associated outflow boundaries, will
move into West Alabama either late this morning or early this
afternoon. Therefore, rain chances have been adjusted to show the
highest chances in the western counties, especially the northwest.
An area of steep mid-level lapse rates is noted to the northwest
of the forecast area. While the best mid-level lapse rates are
forecast to remain west of Alabama, they will be greater than on
previous days across the state. Last evening's 00Z BMX sounding
also had a bit more dry air aloft than previous days as well.
Therefore, the potential for strong storms capable of producing
gusty winds may be a bit higher than the past two days.

Another MCS may approach the western counties tonight, with high-
res guidance suggesting as early as this evening and other
guidance indicating not until after midnight. Therefore, will not
follow the typical diurnal trend in rain chances. A convectively-
enhanced shortwave trough will move across the area Friday and
Saturday, allowing for a continued enhancement of rain chances.

By Sunday 500 mb heights will be rising as a large upper-level
ridge begins to establish itself across the central US,
strengthening to close to 600 decameters over the Central Plains.
This should result in convection returning to being more diurnal
and decreasing in coverage. Highest rain chances will be in East
Alabama closer to the eastern periphery of the ridge and
shortwaves rotating around the edge of the ridge. Heat indices
will be on the rise and begin to approach or exceed 105 starting
on Monday.

32/Davis

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     73  90  71  89  71 /  40  70  60  40  30
Anniston    72  91  71  88  72 /  40  60  60  50  30
Birmingham  75  90  73  89  74 /  40  70  60  50  30
Tuscaloosa  74  90  73  90  74 /  50  70  60  40  20
Calera      73  90  73  89  73 /  40  60  60  50  30
Auburn      74  89  73  90  73 /  40  60  60  50  30
Montgomery  75  93  74  92  74 /  40  60  60  50  30
Troy        73  91  73  91  72 /  40  60  50  50  30

&&

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

&&

05/08/32

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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
129 PM CDT THU JUL 14 2016

ALZ011-141930-
MARION AL-
129 PM CDT THU JUL 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR MARION COUNTY UNTIL 230 PM CDT...

AT 129 PM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM NEAR BELGREEN TO NEAR EVERGREEN. MOVEMENT WAS
SOUTHEAST AT 25 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
HAMILTON...HACKLEBURG...BRINN...WESTON...BEAR CREEK...PIGEYE...
BEXAR...UPPER BEAR CREEK RESERVOIR...PEARCES MILL...TESSNER...
RANKIN FITE AIRPORT...BYRD AND SHOTTSVILLE.

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 3430 8763 3418 8764 3405 8799 3406 8821
      3429 8818 3432 8811
TIME...MOT...LOC 1829Z 301DEG 20KT 3439 8786 3410 8852

56

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
148 PM CDT THU JUL 14 2016

ALZ012-141945-
LAMAR AL-
148 PM CDT THU JUL 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN LAMAR COUNTY UNTIL 245
PM CDT...

AT 147 PM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM 6 MILES SOUTHWEST OF HAMILTON TO NEAR AMORY.
MOVEMENT WAS SOUTH AT 15 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
VERNON...SULLIGENT...DETROIT...BEAVERTON...LAMAR COUNTY AIRPORT...
BLOOMING GROVE...CREWS...BEDFORD...HENSON SPRINGS...
LAMAR COUNTY PUBLIC LAKE AND PINE SPRINGS.

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 3406 8821 3405 8799 3402 8799 3402 8795
      3379 8795 3370 8825
TIME...MOT...LOC 1847Z 342DEG 15KT 3406 8804 3394 8847

56

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BIRMINGHAM AL
159 PM CDT THU JUL 14 2016

ALZ014-142000-
WINSTON AL-
159 PM CDT THU JUL 14 2016

...SIGNIFICANT WEATHER ADVISORY FOR WINSTON COUNTY UNTIL 300 PM
CDT...

AT 158 PM CDT...DOPPLER RADAR WAS TRACKING STRONG THUNDERSTORMS ALONG
A LINE EXTENDING FROM 8 MILES NORTHWEST OF BRUSHY LAKE TO NEAR BRINN.
MOVEMENT WAS SOUTHEAST AT 25 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THESE STORMS.

LOCATIONS IMPACTED INCLUDE...
HALEYVILLE...LYNN...ARLEY...DOUBLE SPRINGS...ADDISON...NAUVOO...
SARDIS...ASHRIDGE...CORINTH REC AREA...BRUSHY LAKE...ASHBANK...
MORELAND...INMANFIELD...HOUSTON RECREATIONAL AREA...NEEDMORE...
WINSTON FREE STATE BARN...NESMITH...POPLAR SPRINGS...
SMITH LAKE AND HOUSTON.

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 3430 8711 3415 8711 3399 8745 3400 8764
      3430 8763
TIME...MOT...LOC 1858Z 305DEG 22KT 3438 8737 3421 8774

56

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