River Flood Warning 13, NWS Jacksonville, FL

Area Forecast Discussion
National Weather Service Jacksonville FL
945 AM EDT Thu Mar 24 2022

.UPDATE...

Several rainbands moving across the region with locally heavy
rainfall. This will continue through the day with a few breaks in
the steady precip. Temperatures will remain in the upper 60s to
lower 70s in general.

&&

.AVIATION...
[Through 12Z Friday]

A band of heavier rainfall now moving across Jacksonville area
fields with ceilings and visibilities bouncing from MVFR to IFR
Conditions and that will continue for a few hours. A second band
will come through between 16-24 UTC with similar impacts. Just
going to be one of those days where we are going to have to
indicate both conditions in the TAFS.

&&

.PREV DISCUSSION [728 AM EDT]...

.NEAR TERM [Through Tonight]...

Showers with a few isolated thunderstorms continue to move
northeast across the area ahead of the slowly approaching frontal
boundary. The front is currently located just west of our forecast
area, and is expected to nudge its way east across the area
through this afternoon. Waves of upper level energy will pulse
ahead of and along the front today, continuing waves of showers
and storms across the area. Short term convective models show a
stronger wave moving in late morning, and bringing a line of
showers with embedded thunderstorms east across the area through
the afternoon. Thunderstorm potential for today will be less than
yesterday due to cooler temperatures limiting surface based
instability; however, isolated strong to severe storms will be
possible.

The highest probability of strong to severe storms will
be over NE FL this afternoon, where the environment will be
slightly more favorable for strong storm development. The Storm
Prediction Center has a Marginal Risk for severe thunderstorms
over NE FL south of a line from Jacksonville to Gainesville.
Potential severe storm hazards include heavy rainfall, damaging
winds, and an isolated tornado. Thunderstorms are expected to push
offshore this evening, with rain showers expected for the rest of
the evening and into tonight. Showers will taper off from
northwest to southeast overnight as an upper level trough swings
towards the area and pushes the frontal boundary southeast. Dry
conditions are expected by sunrise Friday morning, and wet soils
will contribute to patchy fog development early Friday morning
across the area.

Temperatures will be cooler than yesterday due to cloud cover and
precipitation. Highs will be in the 60s and lower 70s, and lows
will be in the upper 40s and lower 50s tonight.

.SHORT TERM [Friday Through Saturday Night]...

The base of a developing longwave trough over the eastern U.S.
will migrate eastward across the Deep South during the predawn
hours on Friday, pushing the cold front offshore of the FL
peninsula. Deep-layered flow will back to west-southwesterly early
on Friday morning as a series of shortwave troughs pivot eastward
from the Tennessee Valley across the southern Appalachians and
the Carolinas. A much drier air mass will advect into our region,
with cold air advection weakening as a more potent shortwave
trough begins its southeastward dive from the Upper Midwest during
the afternoon hours. West-southwesterly surface winds increasing
to 15-25 mph and plenty of sunshine will result in highs climbing
to the mid 70s at most locations. Westerly winds will then
decouple after sunset on Friday night, and the dry air mass will
allow lows to fall to the mid 40s at inland locations, while a
light offshore breeze keeps coastal lows in the upper 40s to
around 50.

A reinforcing shortwave trough plunging southeastward across the
Ohio Valley on Friday night will pivot eastward on Saturday,
moving off the Mid-Atlantic coast by Saturday evening. This
feature will push a dry cold front across our area by Saturday
evening. Ahead of this reinforcing trough and cold front, breezy
west-northwesterly winds and plenty of sunshine will result in
highs reaching the mid to upper 70s. Winds will shift to
northwesterly on Saturday night, ushering in below normal
temperatures as surface ridging builds along the northern Gulf
coast and cold air advection strengthens. Lows on Saturday night
will plunge to the upper 30s to lower 40s inland, with mid 40s
forecast for coastal locations, where breezy northwesterly winds
will prevail overnight.

.LONG TERM [Sunday Through Wednesday Night]...

Deep troughing positioned over the eastern third of the nation on
Sunday will slowly lift northward and away from our region on
Monday, with a dry northwesterly flow aloft on Sunday and Monday
backing to a more zonal flow pattern by Tuesday and Wednesday.
Breezy northwesterly winds on Sunday will keep highs mostly in the
upper 60s to around 70 despite sunny skies. These values will be
about 8-12 degrees below late March climatology. Surface riding
will then become centered over the north central FL by sunrise on
Monday, allowing for radiational cooling and another seasonably
cold night, with lows again falling to the upper 30s to lower 40s
inland and the mid 40s at the coast. Temperatures will then
quickly rebound, with highs climbing back to the mid and upper 70s
on Monday and then into the low to mid 80s by Tuesday and
Wednesday, with a few upper 80s possible across north central FL
by midweek. A dry air mass and decoupling winds each evening will
keep lows mostly in the upper 40s on Monday night and the 50s on
Tuesday night.

The next storm system that will impact our area will be moving
across Texas on Wednesday and the lower Mississippi Valley on
Wednesday night. Our local pressure gradient will tighten ahead of
this approaching storm system on Wednesday night, with southerly
winds keeping lows in the 60s area-wide. 00Z long term guidance
indicates that dry weather will continue across our region through
Wednesday night as a cold front traverses the lower Mississippi
Valley and the northern Gulf coast, with increasing chances for
showers and thunderstorms now expected later next Thursday and
Thursday night.

.MARINE...

Showers and storms expected through tonight as a frontal system
moves slowly southeast across the waters. Winds will increase
along the front, a Small Craft Advisory is in effect for the
offshore waters this afternoon and evening. High pressure will
build to the southwest Friday, then two weaker cold fronts will
move southeast across the waters Friday night and Saturday night.
High pressure will build to the northwest Sunday, move overhead
Monday, then shift to the east Tuesday.

Rip Currents: SE GA low risk today, moderate risk Friday. NE FL
moderate risk today and Friday.

.FIRE WEATHER...

Waves of showers and thunderstorms will traverse our area today,
with strong thunderstorms containing gusty winds and heavy
downpours expected to develop across north central and coastal
northeast FL from the late morning through the mid-afternoon
hours. Lower cloud cover and lighter westerly surface and
transport winds will result in low daytime dispersion values
across most of southeast GA and the Suwannee Valley today. Showers
will move offshore before sunrise on Friday, with breezy west-
southwesterly surface and transport winds ushering in a much drier
air mass throughout our region. High daytime dispersion are
expected region-wide, and minimum relative humidity values will
fall to around 35 percent during the afternoon hours. Surface and
transport winds will then shift to west-northwesterly, with
transport speeds strengthening further on Saturday, creating
another day of high daytime dispersion values throughout our
region. An elevated fire danger may materialize during the
afternoon hours as minimum relative humidity values plunge to near
critical thresholds.

&&

.PRELIMINARY POINT TEMPS/POPS...

AMG  62  47  73  44  74 /  70  30   0   0   0
SSI  66  51  73  49  75 /  90  60   0   0   0
JAX  67  50  75  45  77 /  90  60   0   0   0
SGJ  71  52  75  49  78 /  90  60   0   0   0
GNV  67  49  75  45  77 /  80  60   0   0   0
OCF  70  50  75  45  77 /  80  60   0   0   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory from 2 PM this afternoon to 9 PM EDT this
     evening for Waters from Altamaha Sound GA to Fernandina
     Beach FL from 20 to 60 NM-Waters from Fernandina Beach to
     St. Augustine FL from 20 to 60 NM-Waters from St. Augustine
     to Flagler Beach FL from 20 to 60 NM.

&&