Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 231933
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
330 PM EDT Fri Jun 23 2017

.NEAR TERM.../Tonight-Saturday/...
Tonight...Deep layer ridging across the northeast Gulf of Mexico to
the western ATLC is expected to drift southward as shortwave trough
pushes across the TN valley and lower MS Valley. The shortwave
expected to shear out as it bumps into the fairly strong ridge over
the wern ATLC. Low level flow is therefore expected to veer a bit to
the southwest overnight with increased winds above the sfc...
especially over the local ATLC waters. In the evening...weak
convergence and daytime heating will lead to very isolated showers
and storms over the inland areas from inland SE GA to near Baker
county and south into Marion county. This activity is largely going
to be weak owing to warm temps/subsidence inversion around 750 mb
making convective updrafts weak. Deep convection should be
dissipated by 11pm-midnight. Overnight lows in the lower to mid 70s
similar to last night. Model soundings and SREF indicate stratus and
possible fog over the Suwannee Valley and possible up into the
Statenville and Homerville area early Saturday morning and included
in the latest forecast. This should dissipate quickly Sat morning.

Saturday...low to mid level ridge axis will be across central FL
while shortwave trough progresses slowly eastwards over the Carolinas
and northern GA. Associated sfc cold front will only gradually move
east to a line from central NC to north central GA by 00z Sun.
Prefrontal trough expected to develop over coastal GA plain to
inland NE FL during the aftn. Combination of diurnal heating and sea
breezes and sfc troughing will lead to isolated to scattered showers
and storms Saturday aftn. Two main areas of possibly scattered
deeper convection...one over the srn zones from around Ocala to
Flagler Beach and the other up over SE GA north of a line from
Pearson to Jesup as possible outflow and deeper moisture pooling
into that area. Elsewhere, subsidence will greatly limit convective
potential and advertised rain chances of 20% or less due to
subsidence aloft. Temperatures will be hot with highs in the low/mid
90s inland to near 90 along the Atlantic coast under the prevailing
southwesterly low level flow. Heat index values will near 105
inland.

.SHORT TERM /Saturday Night thru Sunday Night/...

Sat Night...Ridge axis across North FL continues to weaken with the
approach of cold front through the SE U.S. and some pre-frontal
showers and storms will be possible through the evening and
overnight hours across inland SE GA, and with mid-level flow
increasing there could be a few strong storms with gusty winds.
Elsewhere partly cloudy skies with muggy overnight lows in the
lower/middle 70s inland and upper 70s at the coast.

Sunday...Ridge axis gets suppressed further southward into
Central/South FL while moisture from weakening cold front will
interact with both sea breeze fronts pushing inland. Enough sunshine
before storm activity will still push Max Temps into the lower 90s
most areas with Heat indices still reaching 100-105. Numerous storms
are expected to break out along with sea breeze fronts and with SW
steering flow storm motion will be back towards the East Coast and
high rain chances will exist from the U.S. 301 corridor all the way
through the Atlc Coastal Counties and interaction with the Atlc
Coast Sea Breeze in this area along with some mid level cooling will
allow for a few isolated severe storms with damaging winds the main
threat.

Sun Night...Band of frontal moisture lays out across all of NE FL/SE
GA and expect scattered showers and isolated storms to linger
through the evening and fade after midnight but cant rule out precip
throughout the overnight hours. Rain cooled temps generally
lingering in the lower to middle 70s through the night under Mostly
Cloudy skies.

.LONG TERM /Monday-Friday/...

Monday...Despite the abundant cloud cover a Mid level trof digging
over the SE U.S. will give a bit of energy/cooling aloft over the
region to allow for above normal rain chances to continue along the
old frontal/moisture boundary which will sag into NE FL and interact
with afternoon sea breezes and enough diurnal heating from filtered
sunshine to reach the upper 80s (maybe 90F) and expect at least
Numerous shower/storms from the FL/GA border south through NE FL and
while a few isolated strong/severe storms with damaging winds will
remain possible due to increased mid-level lapse rates, expect slow
storm motion will also help to increase the locally heavy rainfall
threat, especially in areas that already received heavy rainfall on
Sunday.

Tuesday...Mid level trof will move off the SE U.S. coast and just
enough push of drier air from the NW will push into SE GA where only
isolated showers and storms are expected while scattered showers and
storms will re-ignite during daytime heating over NE FL as surface
and steering flow become out of the NE and will result in below
normal Max Temps in the middle/upper 80s.

Wednesday...Sfc High pressure will build into the Carolinas and
expect breezy onshore E/NE flow off the Atlantic and below normal
rain chances with SE GA mainly dry and some diurnal scattered
showers/isolated storms across NE FL, but overall story will be the
cooler temps at the coast with highs in the mid 80s there and upper
80s further inland.

Thu/Fri...Sfc High pressure ridge builds offshore into the Wrn Atlc
and this will veer the steering flow towards the SE and allow for
more of the old frontal/moisture south of the region to lift back
northward across all of NE FL/SE GA and will trend back towards
normal to above normal diurnal scattered to numerous showers/storms.
The onshore flow will keep Max Temps in the middle 80s at the
beaches while inland areas will get back closer to normal values in
the upper 80s/near 90 each day.

&&

.AVIATION...
Sct-lcl broken CIGs around 4-6kft rest of today. Have continued to
not mention any shower or tsra in TAFS at this time due to very low
probabilities. Breezy winds from the south-southeast at the coastal
TAFS will continue through the evening before veering back around
to the southwest and decreasing. A chance of stratus after 08z-
13z over the Suwannee Valley area and may just miss the GNV
terminal. Thus no mention of stratus for GNV at this time. Any
isolated convection at terminals on Saturday not likely until after
18z.

&&

.MARINE...Breezy southerly winds this evening will maintain SCEC
for all area waters...with GFS and NAM showing 1000 mb south
winds of 20-25 kt...and seas pushing up to 4-6 ft offshore
waters...about 3-5 ft nearshore. Winds and seas will be on a
decreasing trend 06z-12z Sat. A weak front will push into the
waters late Sunday night into Monday and this will bring light and
variable winds through mid-week.

Rip Currents: Moderate Risk continues with breezy southeast winds
and 2-3 ft breakers.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  73  93  74  91 /  20  30  30  70
SSI  78  90  77  88 /  10  10  20  70
JAX  74  93  74  91 /  10  20  10  70
SGJ  74  90  75  90 /  10  20  20  50
GNV  73  92  73  91 /  10  30  10  60
OCF  72  91  73  92 /  20  30  10  50

&&

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

$$

Shashy/Hess



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