-- Discussion containing changed information from previous version are highlighted. --
940
FXUS62 KTAE 171050
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
650 AM EDT Mon Jun 17 2024

...New AVIATION...

.SYNOPSIS...
Issued at 255 AM EDT Mon Jun 17 2024

Strong high pressure to the northeast and falling pressure over
the southwest Gulf will drive unseasonably strong easterly breezes
across the region from today through at least Thursday morning.
Dry air flowing out of the high pressure will limit afternoon
thunderstorm potential through at least Wednesday. An easterly
wave will approach the region on Thursday and pass by on Friday,
increasing moisture enough to start a day-to-day increase in PM
thunderstorm coverage which will continue into next weekend.

&&

.NEAR TERM...
(Today and tonight)
Issued at 255 AM EDT Mon Jun 17 2024

A strong 500 mb high will strengthen today over the Carolinas and
expand toward the Northeast U.S.. In response, surface high
pressure will strengthen just off the U.S. Mid-Atlantic coast. At
the same time, a broad area of tropical low pressure over the
southwest Gulf will gradually deepen. Between these two systems
over our area, pressure gradients will tighten today, and a
prolonged period of unseasonably strong easterly breezes will get
underway. This will be a rough week on the waters for mariners,
and for rip current hazards at the beaches.

Satellite-derived Precipitable Water (PW) imagery shows a large
nose of drier air off the Southeast U.S. coast. Drier PW values
of 1.2-1.4 inches have already worked into northeast Florida.
Increasing deep-layer easterly flow today will bring the drier air
across the forecast area, while pushing out yesterdays moist air
mass. Enough lingering moisture could persist over our FL
Panhandle counties for long enough today to support a few
afternoon showers and thunderstorms, but areas east and northeast
of there will see a near-shutdown of convection this afternoon.

&&

.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 255 AM EDT Mon Jun 17 2024

High pressure nosing in from the northeast will keep the air mass
dry, with PW values in the 1-1.4 inch range. These values in the
summertime would typically spell complete convective shutdown.
However, the continuation of unseasonably strong easterly breezes
could support speed convergence at the leading edge of any
mesoscale speed surges, which could be enough to eek out a couple
of weak, low-topped, and fast-moving showers. Have therefore
reluctantly kept 15-30 percent rain chances along and southeast
of a Panama City-Valdosta line, with a dry forecast north of
there.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 255 AM EDT Mon Jun 17 2024

The strong 500 mb high over the U.S. Mid-Atlantic region will
become more east-west oriented on Thursday. It will then weaken
from Friday through next weekend while settling south off the
Southeast U.S. coast.

To its south on Thursday, an easterly wave will work its way
westward from near 70W toward the Southeast U.S. coast, with the
trough axis passing across the forecast area around Friday. NHC
continues to outlook a low chance (30 percent) of tropical cyclone
development within this trough axis before arrival along the
Southeast Atlantic coast. Regardless of development, the main
impact for us will be a disruption of the strong easterly flow as
soon as Thursday afternoon, and then a steady moistening of the
air mass from Thursday night through next Sunday. The forecast
reflects this with a slow and steady increase in rain chances each
day from Thursday through Sunday. I have doubts if moistening can
take place soon enough on Thursday to increase rain chances that
soon, but there is good agreement on sufficient moistening by
Friday for increasing the chance of PM thunderstorms.

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 643 AM EDT Mon Jun 17 2024

Today, expect VFR, with chances of SHRA/TSRA limited by dry air
aloft. Highest confidence is for VCTS at ECP, and it cannot be
ruled out at DHN, but potential was too low to include in the
TAF. Brisk easterly flow gets underway today as the pressure
gradient tightens. Winds may gust around 20 kts from the late
morning into the evening hours, with highest confidence at ABY,
before lowering to closer to 10 kts after sunset.
-- End Changed Discussion --

&&

.MARINE...
Issued at 255 AM EDT Mon Jun 17 2024

A rough week on the waters is coming up, thanks to multiple
upcoming days of unseasonably strong easterly breezes.

From CWF synopsis...A prolonged period of strong easterly breezes
will get underway today, lasting through at least Thursday and
possibly Friday. The strong breezes will be driven by the tight
pressure gradient between strong high pressure off the Northeast
U.S. coast, and a deepening area of tropical low pressure over the
southwest and western Gulf this week. Easterly flow will
demonstrate a familiar rhythm nighttime and morning surges, and
afternoon lulls.

&&

.FIRE WEATHER...
Issued at 255 AM EDT Mon Jun 17 2024

A pattern featuring unseasonably strong easterly breezes will get
underway today and last until about Friday. When combined with
seasonably deep mixing, the result will be a high afternoon
dispersion values that will repeat each day through at least
Thursday, and possibly longer. Otherwise, arrival of the easterly
flow today will push out Sundays moist air mass, so look for
drying today. The drier air will eliminate, or at least limit, the
coverage of afternoon showers and thunderstorms through Wednesday
and possibly Thursday.

&&

.HYDROLOGY...
Issued at 255 AM EDT Mon Jun 17 2024

Widespread or significant flooding is not expected for the next 7
days. Riverine flooding is not expected.

Little, if any, rain is expected through Thursday. Rainfall on
Friday and Saturday should not be hydrologically significant.

Late next weekend, the air mass will start a more substantial
moistening trend. Shower and thunderstorm coverage will increase,
and storm motion may slow down. So starting around next Sunday,
we could see the start of a pattern in which we need to look for
for short-lived runoff issues in intense downpours beneath heavier
thunderstorms.

&&

.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  72  93  74 /  20   0  20   0
Panama City   92  75  92  76 /  40  10  10  10
Dothan        93  71  90  73 /  10  10  10   0
Albany        94  71  91  72 /  20   0  10   0
Valdosta      94  71  92  72 /  10  10  20  10
Cross City    94  70  94  72 /  20   0  30   0
Apalachicola  88  79  89  78 /  40  10  20  20

&&

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

GA...None.
AL...None.
GM...Small Craft Advisory from 8 PM EDT /7 PM CDT/ this evening to 1
     PM EDT /noon CDT/ Thursday for GMZ730-750-752-755-765-770-
     772-775.

&&

$$

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