-- Discussion containing changed information from previous version are highlighted. --
903
FXUS62 KTAE 161328
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
928 AM EDT Sun Jun 16 2024

...New UPDATE...

.UPDATE...
-- Changed Discussion --
Issued at 927 AM EDT Sun Jun 16 2024

Forecast is on track for this morning.
-- End Changed Discussion --

&&

.SYNOPSIS...
Issued at 403 AM EDT Sun Jun 16 2024

A surge of moisture from the south today will support a
significant one-day increase in shower and thunderstorm coverage.
Strong high pressure will develop tonight over the U.S. Mid-
Atlantic region, pushing drier air and unseasonably strong
easterly breezes across the region from Monday through at least
Wednesday. Moisture will increase from Thursday through Saturday
as a fast-moving easterly wave moves off the Atlantic and across
the tri- state area.

&&

.NEAR TERM...
(Today and tonight)
Issued at 403 AM EDT Sun Jun 16 2024

Early this morning, a very moist air mass was located just south
of the forecast area, characterized by Precipitable Water (PW)
values well in excess of 2 inches. In fact, the TBW sounding from
Saturday evening observed a PW of 2.22 inches, which is near the
max moving average for mid-June in the SPC sounding climatology
for TBW. This moist air is spreading northwest and will
overspread areas along and southwest of a Eufaula to Valdosta
line later today. This will really prime the air mass for a large
increase in shower and thunderstorm coverage today. Indeed,
convection has increased rapidly since midnight about 70-80 miles
south of Apalachicola over the warm 85-degree Gulf waters. This
serves as another sign of the expected increase in showers and
thunderstorms further north and inland today.

High temperatures will trend down a few degrees today, due to
increased clouds and rain-cooled air.

Late tonight, low-level flow will turn from southeasterly to more
easterly, bringing drier air. Showers and storms will wane late
this evening and overnight.

&&

.SHORT TERM...
(Monday through Wednesday)
Issued at 403 AM EDT Sun Jun 16 2024

A strong 500 mb high over the Carolinas will expand toward the
U.S. Mid-Atlantic region and strengthen impressively during the
first half of the week ahead. In response, the southern periphery
of strong surface high pressure will bridge down the Southeast
Atlantic coast. This will happen concurrent with development of a
tropical low or perhaps a tropical cyclone over the southwest
Gulf (see NHC Tropical Weather Outlook). An unseasonably strong
pressure gradient will develop between these two features, and a
prolonged period of strong easterly flow will get underway and
crank up on Monday and Monday night. A dry air mass emanating from
the strong surface high to our northeast will funnel into the
forecast area from the northeast and east. PW values will be in
the process of dropping below 1.5 inches on Monday, then bottom
out in the 1-1.5 inch range on Tuesday and Wednesday.

Have reluctantly carried slight chance PoPs forward in the
forecast over our FL counties from Monday through Wednesday, but
PW values well below 1.5 inches suggest a greater potential for
convective shutdown on those days. In the unseasonably breezy
environment, mesoscale speed surges and speed convergence could
generate some transient low-topped convection, which is the
justification for holding onto low PoPs for now.

&&

.LONG TERM...
(Wednesday night through Saturday)
Issued at 403 AM EDT Sun Jun 16 2024

The southern base of the upper trough out near Bermuda today will
get detached from the mid-latitude westerlies, then become
orphaned and transition into an easterly wave as strong high
pressure builds in to its north over the U.S. Mid-Atlantic region.
This easterly wave or inverted trough should pass westward past
the Bahamas on Wed night, then across the FL Peninsula and south
Georgia on Thursday, then across the FL Panhandle and Lower
Alabama around Thursday night.

As low-mid level flow quickly flips out of the southeast behind
this trough axis, a moister air mass will stream in and bring a
return of convection from Thursday through Saturday.

A small but growing number of guidance members do form a closed
low around midweek somewhere within the easterly wave axis. Such
development could happen just about anywhere along or east of the
Florida/Georgia coast. The latest NHC Tropical Weather Outlook
from 2 AM EDT on Sunday reflects this possibility with a low
chance (30 percent) of tropical cyclone formation around midweek.
If this occurs, it would be a fast-moving system coming off the
Atlantic, moving westward or west-northwestward.

&&

.AVIATION...
(12Z TAFS)
Issued at 640 AM EDT Sun Jun 16 2024

VFR conditions through the period. The main concern will be
chances for SHRA with embedded TSRA and THE timing today.
Highest confidence remains at ECP and TLH with TEMPO groups,
and have nudged timing earlier. CAMS continue to indicate
activity in close enough proximity to DHN and ECP to justify
VCTS. Easterly winds become more southerly at DHN, ECP, and
TLH today.

&&

.MARINE...
Issued at 403 AM EDT Sun Jun 16 2024

It is going to be an unseasonably rough week on the waters, as
easterlies start to pick up tonight. The roughest conditions will
come from Tuesday through Thursday. This will also make for
dangerous rip currents along our beaches this week.

A prolonged period of fresh to strong easterly breezes will
develop on Monday and then continue through at least Thursday.
This will occur as pressure gradients tighten between strong high
pressure off the U.S. Mid-Atlantic coast and deepening low
pressure over the southwest Gulf. Small craft advisory conditions
are expected for much of the week ahead, marked by nocturnal
surges and afternoon lulls that are common in easterly flow.

&&

.FIRE WEATHER...
Issued at 403 AM EDT Sun Jun 16 2024

The air mass will moisten substantially today, bringing an
increase in shower and thunderstorm coverage through this evening.
Then unseasonably strong easterly flow will develop on Monday and
continue through about next Friday. This will come with a dry air
mass from Monday through Wednesday, then some moistening on
Thursday and Friday. Given the strong transport winds starting
Monday, look for high dispersion values for much of the week
ahead.

&&

.HYDROLOGY...
Issued at 403 AM EDT Sun Jun 16 2024

Shower and thunderstorm coverage will increase today, posing the
concern for intense rainfall rates within the core of heavier
thunderstorms which could lead to short-lived runoff issues.
However, no widespread or significant flooding is expected.

Rainfall, if any, from Monday through Wednesday will be
hydrologically insignificant. Shower and thunderstorm coverage will
increase from Thursday through Saturday, once again posing the
risk of short-lived runoff issues stemming from intense rainfall
rates beneath the core of heavier thunderstorms. Riverine flooding
is not expected.

&&

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   94  74  94  74 /  50  40  30   0
Panama City   89  76  92  76 /  60  20  30  20
Dothan        94  73  93  73 /  50  30  20  20
Albany        96  73  94  72 /  30  30  20  10
Valdosta      96  72  94  71 /  30  10  20   0
Cross City    93  71  94  71 /  80  40  30   0
Apalachicola  87  79  88  78 /  70  40  30  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late Thursday night for FLZ108-112-
     114-115.

GA...None.
AL...None.
GM...None.
&&

$$

NEAR TERM...Haner
SHORT TERM...Haner
LONG TERM....Haner
AVIATION...LF
MARINE...Haner
FIRE WEATHER...Haner
HYDROLOGY...Haner