234
FXUS62 KFFC 050207 AAB
AFDFFC

Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
1007 PM EDT Thu Jul 4 2024



...Evening Update...

.UPDATE...
Issued at 955 PM EDT Thu Jul 4 2024

The main change to the forecast this evening has been to
introduce a slight chance for showers and thunderstorms across
west-central and northwest Georgia overnight (generally west of
the metro Atlanta area) given decent MLCAPE, CAM output, and a
cold front approaching the Tennessee Valley from the north. While
a few storms could produce frequent lightning and heavy rainfall,
severe storms are not expected.

Martin


&&

.SHORT TERM...
(This afternoon through Friday)
Issued at 215 PM EDT Thu Jul 4 2024

Key Messages:

 - Isolated thunderstorms will remain a concern for Independence
   Day celebrations this evening.

 - A Heat Advisory has been issued for Friday due to expected heat
   index values over 105 degrees.

 - A frontal boundary should lead to more widespread
   thunderstorms in northern and central Georgia Friday afternoon
   and evening.

This Evening and Tonight:

Satellite imagery indicated a broad cumulus field over northern
and central Georgia with the most vigorous cumulus over the
western half of the state. Isolated showers and thunderstorms were
ongoing within the cumulus field (mainly along and west of
Interstate 75). Narrow CAPE profiles and mid level lapse rates
below 5.5 C/km should significantly limit the potential for
stronger convection this evening. Thus severe weather is not
anticipated. Frequent lighting and occasional wind gusts in the 25
to 35 mph range could still be hazardous for anyone celebrating
the Independence day the holiday outdoors.

Heat will remain a concern through this evening and a Heat
Advisory remains in place through 7 PM this evening. Where
thunderstorms and rain showers don`t occur, heat index values
should remain at or above 100 degrees through around 7 PM.
Conditions should improve after 7 PM, but conditions will remain
warm and humid and impacts from the heat could linger, especially
for anyone who has spent the entire day out in the heat.

Concerns for Friday:

A weak cold front will push into the region on Friday. Ahead of
the front hot and humid conditions will be in place across
Georgia. Temperatures in the mid and upper 90s should combine with
dewpoints in the mid 70s to produce afternoon heat indices in the
100 to 108 degree range. A Heat Advisory has been issued for a
large part of northern and central Georgia for Friday afternoon.
Confidence in advisory criteria (heat index of 105 or higher)
being met is highest in east central Georgia. The Heat Advisory
for northwest Georgia is lower confidence due to the potential for
clouds and storms that may disrupt the afternoon heating.

The aforementioned front will serve as a focal point for
thunderstorm development Friday afternoon/evening. Any storms that
from along the front may be efficient rain producers due to
unusually high PW values (at or above 2 inches and above the 90th
percentile for early July). Rainfall rates of 1 to 3 inches per
hour will be possible with the most vigorous storms. Dry ambient
conditions and the limited scope of the more vigorous convection
should keep any flooding threat localized. Severe weather is not
anticipated due to modest mid level lapse rates (5.5 C/km or less)
and a lack of effective shear (15 kt or less).

Albright


&&

.LONG TERM...
(Saturday morning through next Wednesday)
Issued at 215 PM EDT Thu Jul 4 2024

Over the Weekend:

The aforementioned cold front should stall over the region this
weekend. This will allow thunderstorms chances to linger in the
region. The rainfall potential will be highest during the
afternoon and evening hours when diurnal heating will be
maximized. There may however be sufficient low level support for
some isolated rainfall during the overnight and early morning
hours each day. As with Friday, a lack of appreciable shear and
poor mid level lapse rates should limit the potential for stronger
storms.

Heat will remain a potential concern over the weekend for
locations south of the frontal boundary and free of widespread
cloud cover. This largely means that we are monitoring portions of
east central Georgia for potential Heat Advisory conditions.
Though our forecast heat indices have declined by 1 to 3 degrees
with the latest forecast update, there remains a chance that Heat
Advisories will be need on Saturday (60% chance) or Sunday (20%
chance) in east central Georgia.

Next Week:

The large scale weather patter next week should feature troughing
over the north central U.S. and upper level ridge over the
Western Atlantic. This pattern should favor weak subsidence aloft
and keep surface moisture (surface dewpoints between 68 and 75
degree) in place across the Georgia, resulting in continued 20-50
percent chances for thunderstorms each afternoon. In short it is
summer and we will be in a very summer like pattern. Temperatures
will cool some early in the week when a few places may see
afternoon highs fail to reach 90 degrees. Then a warming trend is
favored by the GEFS and EPS as the week progresses, with afternoon
highs returning to the low and mid 90s by Wednesday.

Albright


&&

.AVIATION...
(00Z TAFS)
Issued at 727 PM EDT Thu Jul 4 2024

At the time of this writing, SHRA and TSRA are impacting parts of
Atlanta (ATL, FTY, PDK). Have TEMPOs at ATL and PDK until 02z for
TSRA, VRB wind directions, and low-end gusts (up to 20 kts).
Similar to late last night into this morning, cannot rule out
transient low clouds tomorrow (Friday) morning (especially after
this current rainfall adds moisture to the lower levels of the
atmosphere) but long-lived low cigs/vis are currently not
expected. Winds will be light/calm overnight, becoming WSW to SSW
at 4-8 kts tomorrow. Scattered TSRA are expected tomorrow afternoon.

//ATL Confidence...00Z Update...
Medium overall confidence in the ATL TAF.
Low confidence in cigs/vis potential at ATL tomorrow morning.
Medium confidence on TSRA tomorrow afternoon.

Martin


&&

.PRELIMINARY POINT TEMPS/POPS...
Athens          76  95  74  94 /  10  60  50  70
Atlanta         77  95  75  92 /  20  60  50  60
Blairsville     70  87  69  87 /  20  70  40  50
Cartersville    75  94  73  91 /  20  70  40  50
Columbus        77  96  76  95 /  20  50  50  80
Gainesville     77  93  75  92 /  20  70  50  60
Macon           76  96  75  94 /  20  40  40  80
Rome            77  95  74  93 /  20  70  40  40
Peachtree City  75  95  73  93 /  20  60  50  70
Vidalia         76  97  76  95 /  10  30  20  80

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM to 8 PM EDT Friday for GAZ001>005-
011>013-019>025-027-030>039-041>062-066>076-078>086-089>098-
102>113.

&&

$$

SHORT TERM...Albright
LONG TERM....Albright
AVIATION...Martin