Flash Flood Warning 12, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
106 AM CDT Wed May 30 2018

.UPDATE...
For 06Z Aviation.

&&

.SHORT TERM...

Alberto has now moved out of Alabama and was located in south
central Tennessee. The main rain mass associated with this
feature was also just north of central Alabama. But there were a
few convergent rain bands rotating around Alberto that will still
impact the area tonight. Will go ahead and let the Flash Flood
Watch expire because widespread heavy rains are not .
Precipitable Water values remain over 2 inches area wide and with
some breaks in the clouds, SBCAPES jumped to near 2000.
Therefore, some thunder and localized heavy rainfall is not out of
the question overnight. With the loss of daytime heating, the
intensity of the showers should go down. Made some adjustments on
pops per radar and expectations.

75

.LONG TERM...
Thursday through Monday.

Thursday will be a transition day across Alabama as the remnants of
Alberto and its associated trof lift away from Alabama and the
upper ridge over Texas nudges east of the Mississippi River. Mainly
diurnal afternoon thunderstorms will develop on Thursday, with the
better chances east of I-65 due to higher 500mb heights west of
I-65. A northwest upper flow pattern will develop east of the
Mississippi River Friday through the weekend. This pattern this time
of year favors MCS development and the threat of damaging
straight-line winds. Warm and high low level theta-e air on the
eastern periphery of the upper ridge will advect into Central
Alabama Friday and Saturday. The GFS and ECMWF models are showing
surface based CAPE values Friday and Saturday afternoons between
3000 and 4000 J/kg. Will add a low confidence severe for Friday and
Saturday. A more significant short wave trof will rotate down the
eastern periphery of the upper ridge Saturday night or Sunday.
Given the uncertainty of the timing, will hold off mentioning severe
for Sunday at this time.  The upper ridge will likely expand farther
eastward by early next week and result in less convective activity
across central Alabama.

58/rose

&&

.AVIATION...
06Z TAF Discussion.

Wrap around bands now moving through southern and eastern portions
of Central Alabama. Mainly seeing rain with the activity near ANB
and ASN, while thunderstorms are prevelant near MGM. Look for the
conglomeration to continue slide east and north through the night.
Unsure if the thundertorms will hold together by the time it works
into ANB and ASN. Will re-evaluate closer to 9Z and see if TSRA
needs to be added here. May see a break in the activity this
mnorning then redevelopment this afternoon. A few of the short
term models are then bringing in a third wave across the north and
west and the very tail end of the forecast cycle. More on that in
the next discussion and set of TAFS.

16

&&

.FIRE WEATHER...

A moist pattern is expected through at least midweek, with a drier
and warmer trend for Thursday through the weekend. A northwest
flow for the end of period may result in scattered showers during
the evening and morning hours. Patchy fog and low clouds will be
possible tomorrow morning and again Thursday morning. No fire
weather concerns at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     83  69  88  70  88 /  60  30  50  30  60
Anniston    83  70  88  71  89 /  60  30  50  30  60
Birmingham  85  71  90  73  91 /  60  30  40  30  40
Tuscaloosa  88  72  92  73  93 /  60  20  30  20  40
Calera      85  71  89  72  90 /  60  20  40  20  40
Auburn      82  69  86  71  88 /  70  30  50  20  40
Montgomery  87  71  91  72  92 /  70  30  40  10  30
Troy        86  70  90  71  91 /  70  30  50  10  30

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
759 PM CDT Tue May 29 2018

ALZ011>015-017>050-310400-
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-
759 PM CDT Tue May 29 2018

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

.DAY ONE...Today and Tonight.

A few locations may experience heavy rainfall overnight. This
rainfall is not expected to be widespread, but some places could have
some minor flooding.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Tropical showers are anticipated again on Wednesday. Isolated
locations may experience some flooding, especially where the grounds
are already saturated or are prone to flooding.

A pattern favorable for organized convective systems to impact
Alabama will develop later this week. There is a low confidence for
damaging straight-line winds on Friday and Saturday, mainly along and
east of I-65.

.SPOTTER INFORMATION STATEMENT...

Activation of storm spotters and emergency management may be
necessary Friday and Saturday.