Flash Flood Warning 5, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
1201 AM CDT Wed May 23 2018

.UPDATE...
Aviation Discussion.

&&

.SHORT TERM...

Weak troughing remains entrenched across the area with high
precipitable water (PWAT) values near 2.00 inches from this
morning's sounding contributing to very efficient warm rainfall
processes with convection.

Again today, the higher rain chances are roughly along and east of
the Interstate 65 corridor as relatively drier conditions aloft
with weak subsidence exists across the western portion of the
forecast area.

Potential will exist for localized flooding in areas that
experience multiple storms within a short duration or storm
mergers over the next few days. Gusty showers with a few
thunderstorms will also remain a risk with convection mainly
during the afternoon into the early evening hours with peak
surface based instability.

For the extended period, increased shower/storm coverage further
for this time period as a weakness in the broad ridging becomes
more defined late this week and into the upcoming weekend with the
continued low level southeast flow with high PWAT values persisting
throughout the area. While no hazards are listed in the Hazardous
Weather Outlook product at this time, persistent rainfall with
heavy tropical downpours at times may pose an increasing risk for
localized flooding for the remainder of the week and into the
upcoming weekend. Updated 7-day guidance on rainfall across
portions of our far southern counties have some areas potentially
exceeding 5 inches.

05

.LONG TERM...
Wednesday through Monday.

Enhanced rain chances should continue for Wednesday and Thursday
especially south of Interstate 20 where POPs are in the 50-60
percent range. There is where models indicate a stalled 850mb
trough and the remnants of a disturbance.

Models continue to indicate the development of a large trough
encompassing the Southeast states and the Gulf of Mexico for
Friday through Monday. This system has the potential to gain
subtropical characteristics with perhaps an area of surface low
pressure in the Gulf. There is high confidence in unusually wet
conditions during this period, and widespread 60-70 POPs are
reasonable for this type of pattern.

87/Grantham

&&

.AVIATION...
06Z TAF Discussion.

Isolated showers and storms continue tonight, mainly south of the I-
85 corridor. Cannot rule out isolated showers anywhere overnight,
but chances are low near forecast terminals. Low level moisture
remains high and with calm winds at most locations, expect low cigs
and fog to build from east to west across the area, as low as IFR at
times. Scattered showers redevelop before mid day tomorrow. With a
similar setup as today, activity will be slower to affect TCL. Have
included VCSH at all terminals except TCL for now.

14

&&

.FIRE WEATHER...

A moist pattern is expected over the next seven days and should
result in daily rain chances. Patchy fog/low clouds will be
possible each morning particularly where rainfall occurs during
the prior afternoon and evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     66  85  66  86  67 /  40  40  20  50  30
Anniston    66  85  67  86  67 /  50  50  20  60  40
Birmingham  69  87  69  88  69 /  40  40  20  50  40
Tuscaloosa  69  88  69  88  69 /  30  40  30  50  40
Calera      67  85  68  87  68 /  40  50  30  60  40
Auburn      67  82  68  83  68 /  60  70  40  60  40
Montgomery  69  86  70  87  69 /  60  70  40  60  40
Troy        68  85  69  87  68 /  60  70  40  60  40

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
755 AM CDT Tue May 22 2018

ALZ011>015-017>050-231600-
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-
755 AM CDT Tue May 22 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...Wednesday through Monday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

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