River Flood Warning 56, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
552 AM CST Wed Feb 19 2020

.UPDATE...
For 12Z Aviation.

&&

.SHORT TERM...
/Updated at 0319 AM CST Wed Feb 19 2020/

Through Thursday.

The main cold front is now just south of the area. We will
continue to see post-frontal rainfall through the morning. Much of
the afternoon will be dry across the area, although we will begin
to see a surge of moisture from the sw by late afternoon. This
will allow the rain chances to increase in the southwest just
before sunset. By the evening hours, southerly flow will continue
to lift moisture up and over the front, thus increasing rain
chances across the south and eventually into the north overnight.
At this time there appears to be a short 3 to 6 hour rain-free
time frame for the southwest and 6 to 9 hours for the central
sections and 9 to 12 hours for the far north. So not really much
of a time frame for dry conditions.

Rainfall will be widespread by Thursday morning as the trough begins
to work into the region. Look for the front to slowly sag southward
with the post frontal rain clearing 4 to 6 hours afterwards. By
sunset Thursday the best rain chances will be south of the I-20
corridor. Temperatures will also be quite tricky on Thursday as the
highs may occur outside of their regularly scheduled times. As we
work into the evening, rain chances drop off after Midnight across
the area and temperatures will drop into the mid 20s north to mid
30s south.

16

.LONG TERM...
/Updated at 0319 AM CST Wed Feb 19 2020/

Friday through Wednesday.

Colder and drier air is expected Friday and Saturday as ridging
builds in across the region. Morning lows will be in the upper 20s
to low 30s and highs will be in the 40s to 50s. An upper level low
moves eastward through the Rockies early Sunday morning and an
associated surface low deepens across the Great Plains through the
day on Sunday. As this deepening occurs, we start seeing more
southerly flow and could see increased rain chances with the new
warm front lifting northward as early and Sunday afternoon. Guidance
has come into agreement with the timing of best rain chances for
Sunday evening through Monday as the low lifts northeastward and
stretches a cold front through the area. At this point, it doesn't
look like the atmosphere will be able to destabilize ahead of the
cold front, so I have not included thunderstorms in the forecast.
However, some guidance does hint at some instability working in, so
while I can't rule out thunderstorms completely, confidence remains
too low to include in the forecast 6 days out.

Model guidance diverges substantially Tuesday into Wednesday giving
little confidence in the forecast. Since we haven't seen much run to
run consistency with how the Sunday/Monday low pressure system
evolves, it's hard to gauge how the system following that could
evolve towards mid-week. For now, I'll split the difference with 30-
40% chance of rain.

25/Owen

&&

.AVIATION...
12Z TAF Discussion.

Rain shield now south of the I-20 corridor, with IFR/MVFR
ceilings. Look for the rain to continue to slide south and east
this morning, before dissipating this afternoon. This begin to
pivot tonight and rain will increase once again from the SW
overnight, with widespread rain expected by Thursday morning.
Could be a brief window this afternoon with VFR conditions,
especially in the north.

Note: AMD NOT SKED continues for KASN due to observations not
making it into our system. While we are able to see observations,
TAFs will still be generated, but a timely amendment may not
occur.

16

&&

.FIRE WEATHER...

Winds remain out of the north for most of today with the cold
front to our south. A second round of rain moves in Thursday
behind the front. Rain chances finally end Friday through Saturday
as high pressure builds in.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     55  40  45  27  48 /  30  80  90   0   0
Anniston    56  41  47  28  49 /  50  80 100   0   0
Birmingham  55  43  47  30  49 /  40  90 100   0   0
Tuscaloosa  55  44  48  30  50 /  40  90 100   0   0
Calera      56  44  47  30  49 /  50  90 100  10   0
Auburn      60  44  47  33  48 /  60  80 100  40   0
Montgomery  62  49  51  34  52 /  60  90 100  20   0
Troy        65  50  53  36  51 /  60  90 100  40   0

&&

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

&&

Hazardous Weather Outlook
National Weather Service Birmingham AL
323 AM CST Wed Feb 19 2020

ALZ011>015-017>050-201230-
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-
323 AM CST Wed Feb 19 2020

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

.DAY ONE...Outlook through Tonight.

Many river basins across Central Alabama are in flood stage. Please
see the latest river statements for specific details.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

River basins will continue to experience flooding over the next
several days. Please see the latest river statements for specific
details.

.SPOTTER INFORMATION STATEMENT...

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