374
FXUS64 KMEG 022007
AFDMEG

Area Forecast Discussion
National Weather Service Memphis TN
307 PM CDT Tue Jul 2 2024

...New SYNOPSIS, DISCUSSION...

.SYNOPSIS...
Issued at 307 PM CDT Tue Jul 2 2024

Hot and humid conditions will plague the Mid-South Wednesday and
Thursday as heat indices climb above 105 degrees areawide, with
some areas exceeding 110 degrees. A few afternoon showers or
thunderstorms may provide some relief from the heat, but coverage
will be limited. Rain chances will increase Friday as a cold front
moves into the region. This will also result in a slight cooldown
as we head into the weekend. Rain chances will linger through the
weekend, increasing again early next week.

&&

.DISCUSSION...
(This evening through next Monday)
Issued at 307 PM CDT Tue Jul 2 2024

A 596 dam subtropical ridge remains anchored over the Lower MS
Valley this afternoon. Large scale subsidence continues to suppress
cloud cover over the CWA and has nudged temperatures into the 90s
pretty much area wide. Dewpoints remain slightly below normal,
keeping heat indices in the 90s. This looks to change for tomorrow
as southerly flow continues to advect moisture into the region,
pushing precipitable water from near 1.00" this afternoon to ~1.9"
by this time tomorrow. A few showers will be possible as early as
late morning tomorrow with additional scattered, diurnal
convection during the afternoon. Coverage looks to be limited
during the day, favoring West TN, northeast AR, and southeast MO.
With temperatures warming into the mid/upper 90s tomorrow, heat
indices will jump into the 105-113F range. This will necessitate
an Excessive Heat Warning across much of the area with a Heat
Advisory for the remainder of West TN and north MS.

The heat and humidity will also bring relatively strong
instability to the table tomorrow. While isolated storms are
possible areawide, most of the convection is expected to fire to
our north in the OH Valley. This activity may pose a marginal
severe weather risk as they approach northeast AR and West TN
during the evening downstream of a subtle shortwave trough. MLCAPE
on the order of 2500 J/kg will combine with effective bulk shear
near 20-25 kts which may be just enough to support a few multicell
clusters capable of damaging wind and locally heavy rainfall.
Again, this is a pretty limited threat, but nonzero nonetheless.

Similar conditions are anticipated on Independence Day, albeit
perhaps a degree or two "cooler". We will again see scattered
afternoon thunderstorms but the spatio-temporal confidence is less
than tomorrow. Given a similar environment, the potential for
damaging wind and locally heavy rainfall will exist, mainly over
the northern half of the area where deep-layer shear will be
greatest. This uncertainty will also preclude the issuance of a
heat headline for Thursday. Will play this situation day-to-day,
likely issuing a headline for Thursday by this time tomorrow.

A stronger wave will move through the Midwest on Friday and Friday
evening, driving a cold front south across the CWA. This looks to
be the most favorable period for widespread rainfall over the next
week. Precipitable water is forecast to increase to 2.3+ inches
ahead of this front which is in the 90-97th percentile of
climatology. Thus, there is a risk for localized heavy rainfall
with this system.

Slightly cooler conditions are anticipated this weekend with
temperatures dropping into the upper 80s and lower 90s. Rain
chances will linger Saturday and Sunday as the upper-level
trough axis remains to our west, favoring areas along/south of
Interstate 40. There is a lot of uncertainty in the forecast
heading into next week. The most likely scenario is the trough
affecting the area this weekend persists over the eastern CONUS
with a ridge developing over CA into the Great Basin. This spells
temperatures near to slightly below normal with rain chances each
day. However, there are some outlying ensemble solutions that
depict the ridge setting up farther east which means drier and
warmer conditions. The other fly in the ointment is Hurricane
Beryl. Guidance begins to diverge on the storms path late in the
period with some models bending the remnants northwest into TX and
eventually toward the Arklatex. Others keep this circulation over
Mexico. Certainly bears watching, but confidence remains low.

MJ

&&

.AVIATION...
(18Z TAFS)
Issued at 1210 PM CDT Tue Jul 2 2024

VFR conditions will prevail through the period. Convection looks
to develop tomorrow afternoon with greatest thunder coverage
affecting JBR and MKL. Scattered coverage appears more likely for
MEM and TUP.

DNM

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Excessive Heat Warning from 10 AM to 8 PM CDT Wednesday for
     ARZ009-018-026>028-035-036-048-049-058.

MO...Excessive Heat Warning from 10 AM to 8 PM CDT Wednesday for
     MOZ113-115.

MS...Excessive Heat Warning from 10 AM to 8 PM CDT Wednesday for
     MSZ001-007-008-010>012-015>017-020>024.

     Heat Advisory from 10 AM to 8 PM CDT Wednesday for MSZ002>006-
     009-013-014.

TN...Excessive Heat Warning from 10 AM to 8 PM CDT Wednesday for
     TNZ048>050-088-089.

     Heat Advisory from 10 AM to 8 PM CDT Wednesday for TNZ001>004-
     019>022-051>055-090>092.

&&

$$

PUBLIC FORECAST...MJ
AVIATION...DNM