Heat in Missouri, June 23, 2024

Area Forecast Discussion
National Weather Service Memphis TN
1013 AM CDT Sun Jun 23 2024

...New UPDATE...

.UPDATE...
Issued at 1005 AM CDT Sun Jun 23 2024

A weak cold front currently stretches from the Great Lakes
southwestward to Southeast Missouri/North Central Arkansas. A
broken line of showers is occurring ahead of the front from
Northwest Tennessee are East-Central Arkansas. Will update to
bump up POPS based on current coverage on radar. Expect coverage
to expand as additional thunderstorms develop as peak daytime
heating occurs. Will also bump up winds as winds are gusting a
little higher ahead of the front. Update will be out shortly.

KRM

&&

.SYNOPSIS...
Issued at 505 AM CDT Sun Jun 23 2024

An approaching weak cold front combined with a warm, moist, and
unstable airmass may result in the potential for isolated to
scattered showers and thunderstorms across portions of the Mid-
South, especially during peak daytime heating. A strong to perhaps
isolated severe thunderstorm is possible with damaging winds and
localized heavy rainfall as the main threats. This humid airmass
combined with very hot temperatures will produce heat index values
at or above 105 degrees at times through Tuesday. A cold front
will bring a better chance for showers and thunderstorms on
Wednesday with slightly cooler temperatures. A return of hot
temperatures is possible towards next weekend.

&&

.DISCUSSION...
(Today through Saturday)
Issued at 505 AM CDT Sun Jun 23 2024

GOES-16 Water Vapor satellite trends show a shortwave trough
located from the Great Lakes Region back through the Central
Plains. Latest surface analysis places a cold front from northern
Illinois to northwest Missouri and southern Kansas. Regional
WSR-88D radar trends show the trailing edge of showers and
thunderstorms just upstream of the Mid-South over portions of
southeast Missouri. Very warm and humid conditions persist ahead
of this front with temperatures ranging from the lower 70s along
the Tennessee River and middle 70s to around 80 degrees elsewhere.

Short-term models including the latest CAMs show the upstream
convection dropping into the northern third of the area this
morning and weakening as better forcing moves east into the Ohio
Valley. Model soundings indicate the potential for re-development
as convective temperatures are reached during peak heating.
Surface-based CAPE values rising to or above 2000 J/kg and around
20 kts of shear suggest a pulse-type character to any convection
that develops. Isolated to low end scattered pops seem reasonable
given the very conditional environment that will be in place
across the area. Additionally, mid-level lapse rates are expected
to be weak which may temper the overall severe weather threat to a
degree. Damaging winds will be the primary severe weather threat
if any thunderstorms can become severe. Localized heavy rainfall
will also be possible as precipitable water values rise up to
around 2 inches.

Surface dewpoints are expected to pool ahead of this front today
as temperatures rise into the 90s this afternoon. These hot
temperatures combined with high dewpoints will result in heat
index values rising at or above 105 degrees. Consequently, the
existing Heat Advisory was expanded to cover the remainder of the
Mid-South until early this evening. Additional Heat Advisories
look likely especially along and west of the Mississippi River on
Monday and across most of the Mid-South on Tuesday. Some
uncertainty exists for heat headlines on Monday east of the
Mississippi River as this front will result in slightly lower
dewpoints.

Long term operational and ensemble model trends continue to
indicate a better potential for showers and thunderstorms across
most of the Mid-South on Wednesday as a mid-level trough and
associated cold front move through the Lower Mississippi and
Tennessee Valleys. A few of these thunderstorms may have the
potential to become strong to severe as the parameter space will
be slightly better than today. Slightly cooler temperatures are
expected for late this week followed by a return of very hot
temperatures as the upper-level ridge builds back into the region
by next weekend.

CJC

&&

.AVIATION...
(12Z TAFS)
Issued at 605 AM CDT Sun Jun 23 2024

No major changes from previous TAF. Winds will be a bit gusty as a
cold front approaches MEM. Coverage of showers is very isolated
resulting in VCSH to remain at MEM and JBR. MKL has the best
chance of thunder. Guidance is a bit all over the place for winds
post-frontal, but look to remain light in speed. If skies rapidly
clear after FROPA, BR conds may develop.

DNM

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory until 9 PM CDT this evening for ARZ009-018-026>028-
     035-036-048-049-058.

MO...Heat Advisory until 9 PM CDT this evening for MOZ113-115.

MS...Heat Advisory until 9 PM CDT this evening for MSZ001>017-020>024.

TN...Heat Advisory until 9 PM CDT this evening for TNZ001>004-019>022-
     048>055-088>092.

&&

PUBLIC FORECAST...KRM
AVIATION...DNM