151
FXUS62 KJAX 271445
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
1045 AM EDT Thu Jun 27 2024

...New UPDATE...

.UPDATE...
Issued at 1037 AM EDT Thu Jun 27 2024

Adjusted the timing and coverage of PoPs some through the afternoon,
but otherwise the forecast remains on track this morning.

Moist southwest flow has already initiated a few isolated storms
along the Big Bend of FL this morning. With further
destabilization, numerous showers and scattered storms will
develop and spread ENEward across NE FL as the Gulf sea breeze
tracks inland through the rest of the morning and early afternoon.
During the early to mid afternoon hours (2-6 PM) the interaction
between the Gulf sea breeze, pinned Atlantic sea breeze, and
ongoing storm outflows will lead to strong and possibly
marginally severe pulse t`storms. While showers and storms are
possible anywhere today, the favored area for the stronger/severe
convection will be along the I-95 corridor eastward to the beaches
where a few storms could produce downburst winds around 40-60
mph. Additionally, with PWATs increasing toward two inches,
rainfall rates on the order of 3-5" per hour are possible and
could lead to localized flooding threats this afternoon,
especially at locations that have received rain the past couple of
days.

Activity will generally push eastward off the coast and fade early
this evening, though a week frontal zone north of the area and a
weakening mid-level trough may continue showers and isolated
storms into the late evening across portions of SE GA.

Temperatures today will push into the mid/upper 90s once again this
afternoon especially for the coastal zones. Further inland,
convective activity through the early afternoon will mute heating a
bit more with highs only reaching the low 90s. Peak heat index
values will be between 100-106F this afternoon.

For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

&&

.SHORT TERM...
(Friday through Saturday night)
Issued at 312 AM EDT Thu Jun 27 2024

Troughing aloft will begin to de-amplify across the southeastern
states on Friday as "Heat Wave" ridging expands eastward from
Texas and the lower Mississippi Valley. Deep southwesterly flow
will continue across our region as a stalled frontal boundary
over GA lifts northward as a warm front by Friday afternoon.
Convection will again be driven initially by the inland moving
Gulf coast sea breeze, with scattered showers and thunderstorms
likely progressing across the I-75 corridor during the mid to late
morning hours, with increasing coverage during the early to mid
afternoon hours across northeast FL as the Gulf coast sea breeze
progresses towards the I-95 corridor, and categorical POPs were
maintained for locations between I-75 and I-95. Outflow boundaries
propagating northward into southeast GA will also ignite numerous
afternoon and early evening thunderstorms, as southwesterly flow
advects deep moisture northward in the wake of the retreating
warm front, with PWATs spiking above 2 inches area-wide.

Mid-level temperatures will remain mild and east-northeasterly
storm motion should remain brisk on Friday, with convection
likely pulsing as it encounters the pinned Atlantic sea breeze
boundary along the I-95 corridor, with a few strong storms
possible where mesoscale boundaries collide. Highs will
generally reach the low to mid 90s area-wide, with heat index
values expected to remain just below Heat Advisory criteria.

Showers and thunderstorms may diminish more quickly on Friday
evening as ridging aloft builds into our region and the axis of
Atlantic surface ridging begins to lift northward across the FL
peninsula, resulting in weakening southwesterly flow. Lows will
fall to the low and mid 70s inland and the upper 70s at coastal
locations.

Ridging aloft expanding across the southeastern states this
weekend will allow the axis of Atlantic high pressure to lift
northward towards our area on Saturday. Low and mid level flow
will back to a westerly direction, and a loosening local
pressure gradient will allow for the Atlantic sea breeze to
develop earlier on Saturday afternoon, with this boundary
progressing inland and across the I-95 corridor by the
mid-afternoon hours. Deep moisture, featuring PWATs above 2
inches, will persist throughout our area, resulting in
numerous afternoon thunderstorms developing along the Gulf
and Atlantic sea breezes, with mesoscale boundary collisions
expanding coverage into inland southeast GA during the mid
to late afternoon hours. Likely POPs were placed in the
forecast grids area-wide on Saturday, with slower storm motion
possibly resulting in locally heavy rainfall amounts, especially
along the U.S. Highway 301 corridor, where the Gulf and Atlantic
sea breezes will likely collide by late afternoon. Rising heights
aloft will allow highs to tick upwards by a few degrees, with
mid 90s inland and lower 90s at coastal locations. Heat index
values may reach Heat Advisory criteria during the early to mid
afternoon hours before convection and cloud cover increase
during the mid to late afternoon.

Mesoscale boundary collisions may keep scattered convection
going through the mid-evening hours on Saturday at inland
locations. Debris cloudiness will then thin out after midnight,
with lows again falling to the low and mid 70s inland, ranging
to the upper 70s at coastal locations.

&&

.LONG TERM...
(Sunday through Wednesday)
Issued at 312 AM EDT Thu Jun 27 2024

Ridging aloft that expands into the southeastern states this
weekend will briefly retrograde westward early next week as
troughing progresses across the Great Lakes states and New
England. Low and mid level flow will continue to weaken and
will shift to north-northeasterly on Sunday, setting up
a collision of the Atlantic and Gulf coast sea breezes during
the late afternoon hours for locations along and west of U.S.
Highway 301, where numerous to categorical POPs were placed
in the forecast grids. Slow storm motion on Sunday could
present a risk for locally heavy rainfall for these inland
locations by late afternoon. Deep moisture will otherwise
persist area-wide, fostering scattered to numerous mainly
afternoon and evening thunderstorms that will develop along
mesoscale boundaries. Highs on Sunday will again soar to the
mid 90s inland and lower 90s at coastal locations.  Convection
may linger into the early evening hours on Sunday along the
I-75 corridor as well as inland southeast GA. Debris cloudiness
will thin out overnight, with lows generally falling to the
mid 70s inland, ranging to the upper 70s at coastal locations.

Troughing aloft diving southeastward towards the New England and
Mid-Atlantic coasts on Monday will drive another weakening
frontal boundary into the southeastern states. Low and mid level
flow will veer to southwesterly as the axis of Atlantic high
pressure sinks southward, resulting in convection being driven by
the inland moving Gulf coast sea breeze across northeast and north
central FL, while numerous afternoon and evening thunderstorms
develop across southeast GA near the approaching frontal boundary.
Stronger storms will be possible along the I-95 corridor as
convection potentially intersects a pinned Atlantic sea breeze
boundary. Highs may nudge downwards by a few degrees on Monday as
convection potentially develops earlier in the afternoon. The
presence of the stalling frontal boundary could keep scattered
to numerous showers and thunderstorms going through the evening
hours across southeast GA. Lows on Monday night will again fall
to the mid and upper 70s.

Long range guidance indicates that troughing aloft will nudge
offshore of the Mid-Atlantic and New England coasts on Tuesday,
allowing ridging to again expand back into the southeastern states
by midweek. Scattered to numerous mainly afternoon and evening
thunderstorms are expected again on Tuesday as the frontal
boundary lingers across southeast GA and deep moisture persists
across our area. Convective coverage may begin to decrease by
midweek as a more subsident air mass builds overhead, especially
closer to the ridge aloft across southeast GA. Scattered afternoon
and evening thunderstorms will still remain possible for northeast
and north central FL along inland moving sea breezes and other
mesoscale boundary collisions. Highs will nudge upwards as we move
towards Independence Day, with mid to upper 90s expected at inland
locations beginning on Tuesday, with lower 90s for coastal locations.
Heat indices may also reach Heat Advisory criteria (108 degrees)
towards Tuesday and especially Wednesday.

&&

.AVIATION...(12Z TAFS)
Issued at 742 AM EDT Thu Jun 27 2024

Outside of t`storm influences, VFR conditions will prevail along
with southwesterly winds around 6-12 kts with occasional gusts
around 15-18 kts. Increased confidence in t`storm impacts at all
sites for this afternoon, with convection possible as early as 15z
at KGNV. Airfields along the I-95 corridor to the coast
convective window appears to be roughly 18z-22z as activity shifts
eastward into the Atlantic. Main concerns with storms this
afternoon will be erratic outflow winds possible up to 30- 40kts.
VFR conditions and predominant southwest flow at or below 5 kts
will develop after 00z.

&&

.MARINE...
Issued at 312 AM EDT Thu Jun 27 2024

High pressure ridging over the area with fairly consistent
troughing will create winds predominately from the southwest in
the mornings and overnight and then shifting to south-
southeasterly in the afternoons as the sea-breeze makes its way
onshore. Daily afternoon showers and storms are possible over the
local waters into the weekend that could linger into the evening
hours.

Rip Currents: Moderate rip current risk continues at NE FL and SE
GA beaches today.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  93  73  94  73 /  70  50  70  30
SSI  93  76  92  79 /  60  50  60  30
JAX  95  75  95  75 /  70  40  70  20
SGJ  94  77  93  76 /  70  30  70  30
GNV  93  75  94  74 /  70  20  70  10
OCF  91  76  94  74 /  70  20  70  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

$$