National Weather Service Raw Text Product

481 
FXUS62 KJAX 260143
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
943 PM EDT Sun Apr 25 2021

.UPDATE...

Late evening surface analysis depicts high pressure (1025
millibars) settling across the Deep South, pushing a weak cold
front over south FL. Aloft...a negatively tilted trough was
digging from Hudson Bay southeastward into New England, while
ridging was centered over the Bay of Campeche. This weather
pattern was creating a deep and dry northwesterly flow pattern
across our region, with low level flow veering to northerly per
the evening sounding at Jacksonville. A batch of stratocumulus 
cloudiness was diving south-southeastward across most of  
southeast GA, and this cloud cover has been mostly evaporating as
it attempts to cross the FL border into Nassau County. Otherwise,
fair skies prevail elsewhere, with temperatures at 01Z falling
through the 60s and dewpoints mostly in the upper 50s to mid 60s.

High pressure will shift eastward tonight and Monday, becoming
centered along the U.S. eastern seaboard as troughing aloft cuts
off over the Canadian Maritime region, with heights aloft rising
locally as ridging begins to build north-northeastward from the
southwestern Gulf of Mexico. Fair skies will prevail nearly area-
wide after midnight tonight, with decoupling winds inland allowing
lows to fall into the 50s, while a light onshore breeze keeps
coastal lows in the low to mid 60s. Our local pressure gradient 
will tighten as high pressure approaches the coastal Carolina 
region, with breezy east-northeasterly winds developing at coastal
locations by the mid-morning hours, followed by breezy conditions
spreading inland as the day progresses. Convergent onshore low-
level flow could even develop a few showers over the Atlantic
waters adjacent to northeast FL, but only a sprinkle or two may
make it onshore across coastal Flagler and St. Johns Counties
during the afternoon hours. Breezy onshore winds will keep coastal
highs in the mid to upper 70s, while inland highs reach the low to
mid 80s. 

&&

.MARINE...

High pressure over the southeastern states this evening will 
shift eastward on Monday, moving off the Carolina coast by Monday 
evening. Onshore winds will develop overnight and will briefly 
strengthen to Caution levels of 15-20 knots offshore on Monday,
with speeds near shore increasing to near 15 knots. Seas of 3-5
feet will prevail both near shore and offshore from Monday through
Thursday night. High pressure will remain anchored off the 
southeast U.S. coast through Thursday and will then shift eastward
towards Bermuda on Friday as a cold front enters the southeastern
states and low pressure develops over the lower Mississippi 
Valley. Onshore winds through midweek will shift to southerly by 
Thursday and southwesterly on Thursday night and Friday. 

Rip Currents: Strengthening onshore winds will create a high-end
moderate risk at area beaches on Monday and Tuesday. 

&&

.FIRE WEATHER...

Strengthening east-northeasterly surface and transport winds will
create good dispersion values nearly area-wide on Monday
afternoon. Minimum relative humidity values will fall to near 35
percent at inland locations along and west of U.S. Highway 301 on
Monday afternoon. Surface and transport winds will then shift to
east-southeasterly on Tuesday, with slightly lower speeds
expected. Minimum relative humidity values will fall to around 35
percent across inland portions of southeast Georgia.

&&

.COASTAL TIDAL LEVELS...

The perigean full moon ("Supermoon") on Tuesday night will combine
with persistent onshore winds to create increasingly elevated
tidal levels beginning with the Monday evening high tide. We
currently expect tidal levels to remain at action stage along the
Atlantic coast during the evening high tides through at least
midweek. Water levels within the St. Johns River basin may become
elevated around midweek and could reach Action stage around times
of the evening and overnight high tides. 

&&

.PREV DISCUSSION [754 PM EDT]...

.NEAR TERM [Tonight through Monday]...High pressure will build
into the area tonight from the northwest. Skies will be clear with
light winds overnight. Low temperatures will fall into the 50s
inland and into the lower 60s coast. Monday will be mostly sunny 
with breezy northeast winds, especially near the coast. Highs 
will range from the mid 70s coast the lower 80s inland.


.SHORT TERM [Monday night Through Wednesday night]...Upper ridge
over the central Gulf region will shift east over the area as an 
upper low digs over the sw U.S. At the surface, high pressure 
just off the Carolina coast will shift east over the Atlantic 
maintaining an onshore flow for our area. Temperatures will be 
seasonal with dry conditions continuing through the period.


.LONG TERM [Thursday Through Sunday]...Ridging at the surface and
aloft will be located across the area on Thursday before shifting
to the southeast on Friday. A front stalling over the area will 
bring a period of unsettled weather with large 12z model differences
with the handling of the sw low. ECMWF tries to phase the upper low
with a northern stream shortwave while the slower GFS keeps the 
two separate. Will keep a chance of showers and storms through the
weekend with temperatures at or above normal.


.AVIATION...
[Through 00Z Tuesday]

VFR conditions will prevail at the regional terminals. East-
northeasterly surface winds will increase after sunrise on Monday,
with sustained speeds increasing to near 15 knots and gusty at 
SGJ and CRG towards 15Z, with sustained speeds elsewhere
increasing to 10-15 knot range by 16Z.

&&

.PRELIMINARY POINT TEMPS/POPS...

AMG  54  82  54  85  57 /   0   0   0   0   0 
SSI  62  76  63  77  65 /  10  10  10   0   0 
JAX  57  81  56  82  62 /  10  10  10   0   0 
SGJ  63  79  64  79  64 /  10  10  10   0   0 
GNV  56  84  58  85  58 /   0  10  10   0   0 
OCF  57  85  59  86  60 /  10  10  10   0   0 

&&

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