NWS Jacksonville, FL wrote its last area forecast discussion before the first event at Jan 9, 12:34 PM EST, 21 minutes earlier.
Area forecast discussion, Jan 9, 12:34 PM EST, 21 minutes before
Area Forecast Discussion
National Weather Service Jacksonville FL
1234 PM EST Tue Jan 9 2024
...New AVIATION...
.UPDATE...
Issued at 830 AM EST Tue Jan 9 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
Significant Damaging Wind Event along with Significant Tornado
Risk still on track for this afternoon across all of SE GA and NE
FL. Initial Tornado Watch has already been posted for inland
portions of SE GA/NE FL through 2pm, which will likely be extended
to the Atlantic Coast this afternoon. Timing of event still on
track to entering the inland areas around Noon and exiting the
Atlantic Coastal Counties by sunset. Wind Advisory is already in
effect and getting peak wind gusts in the 40-45 mph range already
with peak gradient wind gusts in the 45-55 mph range still
expected through the day. Max temps will surge into the 70s for
all locations which will provide enough instability for damaging
winds of 60-70mph+ in T'storm activity as it pushes through.
Solid Gale Warning for Coastal Waters, including Storm Warning for
the offshore SE GA waters into the evening hours. Minor Coastal
Flooding does not appear likely along the SE GA coast, but trapped
water along the St. Johns River near downtown JAX is likely to
push water levels into Minor Flood there during the afternoon
hours and through the evening high tide cycle.
&&
.NEAR TERM...
(Today through Tonight)
Issued at 345 AM EST Tue Jan 9 2024
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
A vigorous mid to upper level trough near the Ozarks region will
continue to develop and become negatively tilted today and support
a deepening low pressure center currently over the lower to mid MS
valley that will track NE towards Michigan and the Great Lakes
by this evening. A strong cold front will sweep eastward along
the Gulf coast towards our area by this afternoon with a squall
line of strong to severe thunderstorms that will move quickly
and swiftly eastward through our area between the early to mid
afternoon hours for most, exiting off the SE GA coast into the
Atlantic waters by the late afternoon and off the St Johns and
Flagler county coasts by sunset. Strong dynamics with this system
will keep a very strong low level jet of 45-55 knots and deeper
0-6 km shear of 50-70 knots, which along with good lapse rates
aloft around 6.5 C/km and and rising dewpoints into the upper
60s will create 500-800 J/KG of CAPE ahead of the line. This
will promote a threat damaging wind gusts 50-70 mph or greater,
hail, and isolated tornadoes within more intense storms embedded
within the Squall line. Heavy downpours will yield a quick 1-2
inches of rainfall, with locally higher amounts possible, as the
line of storms will move swiftly through our area, but may still
cause some minor flooding in urban and low lying areas.
A very strong pressure gradient will also create wind advisory
conditions today due to the tight pressure gradient and increased
low level winds fields as the cold front approaches with sustained
winds elevating to around 30 mph late this morning and gusting
45-55 mph this afternoon which may impact high profile vehicles,
break loose tree branches, and cause isolated power outages over
the area ahead of the storms.
Highs will be well above normal today into the low to mid 70s
across inland SE GA and NE FL, mid 70s east of highway 301 with
upper 70s to near 80 degrees along the St Johns river basin.
Tonight, low pressure system will move across the Great Lakes
and drag the front east of the waters with winds then turning
westerly and winds slowly decreasing to below wind advisory
criteria 15-25 mph with gusts to 30-40 after midnight and 10-15
mph by sunrise. Skies will clear as high pressure begins to influence
our area from the west, allowing lows to fall into the upper 30s
over inland SE GA into the Suwannee Valley of NE FL with lower
40s elsewhere.
&&
.SHORT TERM...
(Wednesday through Thursday night)
Issued at 345 AM EST Tue Jan 9 2024
Much quieter and nicer weather Wednesday with dry conditions and
clear except for cirrus clouds, but chillier air with highs only
in the 50s to near 60. Westerly flow will initially be breezy but
high pressure building in from the west will allow winds to drop
off by later in the afternoon. By Wednesday night, the weak high
pressure system around 1019 mb will build in over north central FL
with a broken cirrus canopy, fairly thin, anticipated as flow
aloft backs in response to another mid/upper level trough
developing over the western CONUS. With the light to calm winds,
some frost potential overnight with lows in the mid to upper 30s
from about I-10 northward, and lower 40s south.
On Thursday, a warm front will begin easing northward over eastern
Gulf of Mexico and the FL straits, with the high center having
moved east of the area. Thus, return flow expected gradually
through the afternoon over northeast FL with sky cover increasing
ahead of the approaching warm front. Highs closer to normal but
generally looking at lower 60s area-wide. Looks like rain chances
won't start in association with the warm front until Thursday
evening. The warm front is forecast to move into northeast FL
after midnight and toward sunrise, with high rain chances expected
to materialize over northeast FL as stronger isentropic ascent
occurs, with at least chance POPs also for southeast GA. Low chance
of thunderstorms Thursday evening mainly northeast FL, then all
of the area after midnight with higher probabilities, but MUCAPE
currently projected to be low at about 100-300 K/kg. We can't rule
out a strong storm overnight given the veering wind profile. Not
as cold Thursday night due to clouds and warm advection pattern.
&&
.LONG TERM...
(Friday through Monday)
Issued at 345 AM EST Tue Jan 9 2024
On Friday, an organized low pressure system will be over the Mid
MS valley with a cold front southward in the Gulf of Mexico, aided
by a strong mid/up-per level trough moving through the central
U.S. The warm front over the local area will move quickly northward
Friday morning, while the cold front will be moving rapidly
eastward about 40 mph over the central Gulf coast as the low
pressure system over the MS valley pushes northeast to the Ohio
Valley Friday evening. Widespread showers and scattered thunderstorms
are expected Friday-early Friday evening, with a slight chance of
severe storms as shown by SPC outlooks. Instability of about
400-700 J/kg and bulk shear about 50-65 kt will be more than
adequate for scattered strong to severe storm potential. This
potential will move into Friday evening as well, before the front
and associated showers and storms likely move offshore shortly
after midnight. Following a cold frontal passage Friday night,
weekend high temperatures will drop back down into the 50s to
lower 60s with low temperatures falling into the 30s and 40s,
allowing for frost potential to return for inland southeast
Georgia and the Suwannee Valley. Coldest daytime highs expected
Saturday, and freeze is possible Sunday morning over southeast GA.
In step with the progressive pattern, we may see the sfc high
pressure, that builds over the region on Sunday, to move northeast
by Monday as another storm system moves toward the area. Similar
to Friday morning, we have have another warm front lift over the
area on Monday. As such, we have chance of showers and slight
chance for thunderstorms in the forecast for Monday.
&&
.AVIATION...
(18Z TAFS)
Issued at 1226 PM EST Tue Jan 9 2024
A squall line ahead of a cold front is approaching area terminals,
with VCTS expected within the next 1 to 2 hours at area terminals.
Non TS winds will remain breezy prior to this line of TSRA
arriving, with gusts of 35 to 45 knots expected. Continued to
include TEMPO wind gusts up to 50 knots and IFR ceilings and low
vsbys as the squall line moves across the area. Isolated gusts
greater than 50 knots this are possible in some severe
thunderstorms expected along the squall line. Conditions will
gradually improve this evening as winds shift towards the
southwest, with all areas expected to return to VFR by about 01 to
03Z. Winds will ease overnight, though remain above 10 knots with
higher gusts area wide through the end of the forecast period.
&&
.MARINE...
Issued at 345 AM EST Tue Jan 9 2024
Gale Warnings in effect for the entire waters as winds increase
quickly ahead of a intense low pressure system that will drive a
strong cold front through the area waters this afternoon into
early evening. An associated squall line will sweep eastward
ahead of the cold front this afternoon. Have upgraded the Storm
Watch to a Storm Warning this afternoon over the offshore Georgia
waters as wind gusts will peak around 50 knots as the squall line
approaches and moves east through the waters. Winds will shift
to the west behind the cold front and diminish through the day
Wednesday as weak high pressure builds toward Florida. This high
will shift offshore Thursday as the next frontal system approaches
the area through Friday with increasing showers and a potential
for strong to severe thunderstorms.
Rip Currents: High risk of rip currents in effect for all area
beaches today along with a high surf advisory for surf/breakers
up to 5 to 7 feet. A moderate risk will be expected Wednesday
for all area beaches and winds turn more offshore.
&&
.HYDROLOGY...
Issued at 345 AM EST Tue Jan 9 2024
Still looking at rainfall amounts of 1-2 inches today, though somewhat
less for the southeast most zones. Some brief minor flooding will
be possible but the quick movement of the line of storms will limit
this potential. Latest forecast for area rivers shows parts of
the Santa Fe rising to minor flood stage Thursday night. Other
river rises are expected on the Satilla, Altamaha, and St Marys,
but lower confidence on whether river flooding warnings will be
needed at this time. Stay tuned.
Coastal Flood Potential: Some minor coastal flooding is possible
today given the strong southerly winds and the prior onshore flow
and trapped tides in the St Johns River basin for Duval county,
with rough waves on the river impacting downtown JAX around San
Marco and Riverside areas due to the south wind fetch. Also, some
potential for minor coastal flooding along the coast from Duval
county northward, with support from PETSS guidance of about 1.4
to 1.8 ft MHHW. The advisory will go through this evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 38 54 37 62 / 0 0 0 10
SSI 41 57 41 61 / 20 0 0 10
JAX 41 58 39 61 / 20 0 0 10
SGJ 44 60 42 62 / 40 0 0 10
GNV 42 60 40 63 / 10 0 0 10
OCF 45 61 42 64 / 30 0 0 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Wind Advisory until 10 PM EST this evening for FLZ020-021-023-
024-030-031-033-035-038-122-124-125-132-133-136>138-140-222-
225-232-236-237-240-325-340-425.
Coastal Flood Advisory until 10 PM EST this evening for FLZ124-
125-225-325.
High Rip Current Risk through late tonight for FLZ124-125-133-
138.
High Surf Advisory until 7 PM EST this evening for FLZ124-125-
133-138.
GA...Wind Advisory until 10 PM EST this evening for GAZ132>136-149-
151>154-162-163-165-166-250-264-350-364.
Coastal Flood Advisory until 10 PM EST this evening for GAZ154-
166.
High Rip Current Risk through late tonight for GAZ154-166.
High Surf Advisory until 7 PM EST this evening for GAZ154-166.
AM...Gale Warning until 4 AM EST Wednesday for AMZ450-452-454-472-474.
Gale Warning until 1 PM EST this afternoon for AMZ470.
Storm Warning until 4 AM EST Wednesday for AMZ470.
&&