914
FXUS64 KBMX 092200
AFDBMX

Area Forecast Discussion
National Weather Service Birmingham AL
500 PM CDT Sun Jun 9 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE FOR SEVERE THUNDERSTORM POTENTIAL...
Issued at 431 PM CDT SUN JUN 9 2024

Severe thunderstorms are possible through 2am tonight for areas
generally north of Interstate 85 and Highway 80. This covers
roughly the northern two thirds of Central Alabama. Thunderstorms
are expected to develop within the next few hours across western
Alabama, Mississippi, and Arkansas. These storms will generally
move east southeast through the evening. The atmosphere over the
area is characterized by SBCAPE values ranging from 2500-4000j/kg,
Effective Bulk Shear values up to 35kts, Downdraft CAPE
1100-1300j/kg, CAPE of 1000j/kg in the hail growth zone, but there
is some drier air aloft and poor mid level lapse rates amongst
others. The main thing we are missing at the present moment is a
trigger. Convective temperatures are not enough alone to provide
the forcing necessary for sustain updrafts at this time. A cold
front was located over Tennessee and will only slowly move
southward this evening. There are a few outflow boundaries out
ahead of the front that will most likely be the focus for
thunderstorm development as a short wave moves in this evening. It
appears that if thunderstorms can become organized, they would
move through later this evening with a threat of damaging wind
gusts and large hail. But there remains some doubt as to which
boundary or area of sustained thunderstorms will develop and where.
A watch has been posted for areas west of us and we are
monitoring the this activity for possible watches or warning
later. It also appears that the upper ridge does recede southward
enough for some development too. Made some minor adjustments to
the ongoing forecast but nothing that alters the main message.

75

&&

.SHORT TERM...
(This evening through Monday)
Issued at 146 PM CDT SUN JUN 9 2024

Key Messages:
- Conditional risk for shower and thunderstorm activity through
  tonight, some storms may be severe with a damaging wind and hail
  risk.

Tonight.

Another shortwave impulse associated with a longwave trough will
drop southeast over the Mid-South Region this evening. This
feature is supporting ongoing shower and thunderstorm activity
across portions of Northeast Arkansas and Southeast Missouri. This
activity will move east-southeast with time and it or its outflow
may result in additional shower and thunderstorm development this
evening and overnight with the nearing trough from the northwest
and the advancing surface cold front that will be positioned
roughly along the Interstate 20 corridor before midnight. Winds
will become northwest behind the front with west winds persisting
ahead of the front with speeds from 4-8 mph. Low temperatures will
range from the mid 60s far northwest to the low 70s generally
near and south of the U.S. Highway 80 corridor.

Monday.

The national flow pattern amplifies on Monday with longwave
troughing over the Tennessee Valley extending northeast toward the
upper low located just northeast of Maine while ridging builds
over much of the Plains. The surface cold front will continue to
advance south toward the Gulf Coast through the day. Decreasing
clouds are forecast across the northwest half of the area while
lingering clouds with chances for shower and thunderstorm activity
will continue across the southern half of the area through the
morning hours, becoming increasingly confined to the far southeast
counties after noontime. Dry conditions will return areawide by
the evening hours. Winds will be from the northwest areawide with
speeds from 5-10 mph. High temperatures will range from the low
80s far north and in the higher elevations east to readings around
90 across the far southeast counties.

05

&&

.LONG TERM...
(Monday night through next Saturday)
Issued at 146 PM CDT SUN JUN 9 2024

The main focus during the week will be on increasing heat and
potential heat-related impacts as we reach the warmest temperatures
so far this year towards the end of the week. Upper-level troughing
over the Southeast and a large region of high pressure over the
Central US will drive northeasterly flow across Central Alabama and
highs in the mid 90s. Otherwise, the forecast remains dry for much
of the earlier half of the week with small opportunities for rain
across the far south related to inverted troughing over the
eastern Gulf of Mexico.

86/Martin

Previous long-term discussion:
(Monday night through Saturday)
Issued at 353 AM CDT SUN JUN 9 2024

A significant upper-level trough east of the Mississippi River and
the associated confluence zone will support relative high pressure
moving southward into the Ohio Valley and southern states. A
cooler and much drier airmass will be advected from the north
Monday night with lows ranging from the upper 50s to the mid 60s
from north to south. Dry conditions and low relative humidity
values should continue Tuesday and Wednesday as high pressure
remains in control under northwesterly flow at 500 mb.

While moisture will gradually increase Thursday through Saturday,
the arrival of increased rain chances could be delayed. Models are
trending toward more ridging across the Deep South, keeping a
disturbance in the Gulf of Mexico south of our area through
Saturday. Our latest forecast significantly undercuts the NBM POPs
Thursday through Saturday, and it is possible that most of the
forecast area remains dry.

87/Grantham

&&

.AVIATION...
(18Z TAFS)
Issued at 1220 PM CDT SUN JUN 9 2024

VFR conditions will continue for a few more hours across the
north and will prevail across the south through this evening. A
surface cold front will move south into the area late this
afternoon with chances for showers and some thunderstorms. This
activity is forecast to affect the northern sites as early as 23z
and persist through the night. Rain and storm chances will
decrease into the morning on Monday from north to south with much
of the activity expected to affect the southern sites as early as
12z Monday and persisting through the end of this cycle.

05

&&

.FIRE WEATHER...

Afternoon minimum RHs are forecast to remain above critical levels
over the next few days. Overnight RH recovery should be in the
upper 70s to low 90s. 20-foot winds should run at or less than 7
mph over the next few days, west-northwesterly today, and
northerly on Monday. Some showers and thunderstorms may occur late
this afternoon into tonight as a front moves across the area.
Additional isolated to scattered showers are possible Monday
afternoon across the southern half of the area as the front
finally clears the area. Dry weather is expected from Tuesday
through at least Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     67  83  57  84 /  40  20   0   0
Anniston    67  83  58  85 /  40  20   0   0
Birmingham  68  84  61  85 /  60  20   0   0
Tuscaloosa  70  86  61  86 /  60  20   0   0
Calera      68  85  62  85 /  60  20   0   0
Auburn      70  86  65  86 /  40  30  10   0
Montgomery  72  87  66  87 /  30  30  10   0
Troy        71  89  66  88 /  20  50  20  10

&&

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

$$

SHORT TERM...05
LONG TERM....86/Martin
AVIATION...05