474
FXUS64 KHUN 040755
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
255 AM CDT Thu Jul 4 2024

...New NEAR TERM, SHORT TERM, LONG TERM...

.NEAR TERM...
(Today)
Issued at 254 AM CDT Thu Jul 4 2024

Dangerous heat continues this Independence Day as a strong area of
high pressure just to the southeast of the Tennessee Valley will
continue to support ample sunshine and a warm/humid air mass.
Today may end up being the warmest day of the week so far,
especially in our eastern zones -- with forecast highs in the mid
90s nearly everywhere (and portions of north central and northwest
Alabama reaching the upper 90s). These hot temperatures, combined
with deep moisture (dewpoints in the mid 70s) will produce
dangerous heat index values between 105-109 degrees over a vast
majority of the area. Additionally, urbanized areas (Florence,
Decatur, and Huntsville) may briefly see heat index values exceed
110 degrees due to heat island impacts from localized higher
temperatures. The threat for heat related illnesses, especially
if you have outdoor plans this 4th of July holiday, cannot be
understated. Please exercise extra caution and check on those in
our community who are particularly vulnerable to heat. A Heat
Advisory remains in effect areawide.

Sufficient moisture underneath the ridge may allow for some low
chances for diurnally driven showers/storms (25-40%) during the
afternoon/evening hours. These storms will be disorganized and
short-lived due to the extremely weak shear profile. Latest
guidance is trending down with PoPs (likely due to subsidence
from the ridge), so still think that most locations will remain
dry. However, given the amount of outdoor activities this holiday,
be prepared to move indoors if you hear thunder or see a flash of
lightning.

&&

.SHORT TERM...
(Tonight through Saturday Night)
Issued at 254 AM CDT Thu Jul 4 2024

The Heat Advisory continues overnight due to the very limited
relief from the heat as low temperatures will again range between
75 to 80 degrees in most locations. A mid/upper trough will pivot
from the northern Plains into the Great Lakes late tonight into
Friday. Hi-Res guidance shows an MCS developing along this
boundary well to our north and west this evening over the Ozarks
and drifting toward the Mid South vicinity by early Friday
morning. This activity will likely weaken considerably as its
remnants move into the Tennessee mid/late Friday morning, but it
will still bring some low to medium chances for showers and storms
along with higher cloud cover.

Additional convection will likely redevelop later in the
afternoon/evening along this remnant boundary, where coverage is
forecast to be much higher (80-100%). Depending on how much
destabilization can occur, a few of these storms may become
locally strong with gusty winds and heavy downpours being the
threats. These clouds and high rain chances will be the "wild
card" with respect to heat impacts on Friday. Given highs still
progged to reach the mid 90s and peak heat indices still forecast
to exceed or come close to 105 degrees, will maintain the Heat
Advisory through 7 PM Friday. Should more heating become apparent
and/or rain chances lessen, another solid day of widespread
dangerous heat will likely evolve in this hot/humid air mass.

The frontal boundary will push south and east into central Alabama
Friday night into Saturday. However, with this boundary still in
our vicinity low chances for showers/storms will remain in the
forecast for Saturday. A slightly cooler/drier air mass will help
to keep the dangerous heat at bay, however. Highs in the upper 80s
to lower 90s will be common -- with peak heat index values
remaining below 100 degrees.

&&

.LONG TERM...
(Sunday through Wednesday)
Issued at 254 AM CDT Thu Jul 4 2024

On Sunday, upper level ridging looks to be stretched over the
Atlantic and down through the Deep South. A large upper trough will
dominate the central CONUS but also extend up into the Ohio Valley
and Canada. This leaves the local area in southwesterly flow aloft,
and this will continue through at least Monday night until the trough
finally starts to swing to the east/northeast on Tuesday and
Wednesday. The surface front that is slated to move south of the area
on Saturday is expected to meander over this region through early
next week. Another cold front is then anticipated to progress over
the Ohio Valley by midweek.

For sensible weather, after a dry day on Sunday, daily chances
(generally low to medium, 30-60%) of showers and storms are forecast
through midweek. This is especially true during peak heating
(afternoon hours). Sufficient instability for thunderstorm
development is anticipated, along with shear around 20 knots. While
severe weather is not expected at this time, heavy downpours,
lightning, and some gusty winds will all be possible in any
thunderstorms that do develop. Additionally, the chances of
showers/storms and amount of cloud cover will cause temperatures to
be slightly cooler than we`ve seen this week, with values in the
lower to mid 90s Sunday and Monday and upper 80s to lower 90s Tuesday
and Wednesday. Expecting lows to mainly be in the upper 60s lower
70s each night. Even though the forecast calls for a bit cooler
conditions, it will still be warm (especially early next week).
Please continue to be cautious if you have outdoor plans. Take breaks
in the shade and stay hydrated!

&&

.AVIATION...
(06Z TAFS)
Issued at 1255 AM CDT Thu Jul 4 2024

VFR conditions will be the predominant flight category at each
terminal through the period. Low chances for TSRA/SHRA are
forecast this afternoon, but given low confidence in coverage have
kept a mention of them out of the TAF at this time.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory until 7 PM CDT Friday for ALZ001>010-016.

TN...Heat Advisory until 7 PM CDT Friday for TNZ076-096-097.

&&

$$

NEAR TERM...AMP.24
SHORT TERM....AMP.24
LONG TERM....26
AVIATION...AMP