090 
FXUS62 KJAX 100841
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
441 AM EDT Tue Mar 10 2020

.NEAR TERM [Today Through Tonight]...

Atlantic sfc ridge continues to be positioned just north of the 
area and will shift south and southeast through tonight. As 
result, low level winds currently southeast will weaken and become
more southerly during the day. Upstream, model guidance shows a 
shortwave trough over AL/central and nrn GA pushing eastward 
which should reach our area later this morning and aftn. Radar
shows a swath of rain and showers associated with this trough. This
feature along with weak low level convergence will support a low 
chance of showers (about 15-25 percent) for southeast GA today. 
Further south, model blends, including GFS/ARW/NMM and the HRRR 
suggest a few showers over inland northeast FL this aftn. A few 
showers also expected offshore waters near a sfc trough. Though 
mid and high clouds will be prevalent today until the early to mid
aftn hours, southerly flow will support highs in the mid to upper
70s, with coastal areas being limited to lower to mid 70s due to 
onshore flow. 

Tonight, shortwave trough is expected to push offshore of our 
coast while multilayered clouds continue into the evening hours. 
With lack of meaningful forcing for showers, will go back to POPs 
of around 5-10 percent tonight. Also, anticipate an improvement in
cloud cover overnight. Lows again will drop toward the mid and 
upper 50s. Some patchy fog will be possible inland northeast FL 
zones.

.SHORT TERM [Wednesday Through Thursday]...

Zonal flow will prevail locally through Thursday, with the base 
of a weak shortwave trough currently over the northern Rockies 
moving east-southeastward and reaching the southeastern states by 
Wednesday evening. This shortwave could ignite isolated to widely 
scattered convection over southeast GA during the late afternoon 
and early evening hours, with a majority of the activity remaining
north of our region closer to a stalled frontal boundary that 
will be in place over the Tennessee Valley. An active Atlantic 
coast sea breeze may have just enough moisture to develop isolated
late afternoon convection over the southern St. Johns River basin
and the Ocala National Forest as it moves inland. Otherwise, the 
axis of Atlantic ridging will slip south of our region, resulting 
in gradually deepening west-southwesterly low level flow that will
boost highs into the lower 80s at most inland locations, with an 
afternoon sea breeze keeping coastal highs in the 70s. Lows 
Wednesday night will only fall to the mid and upper 50s.

A similar weather pattern will prevail on Thursday as the frontal
boundary remains stalled across the Tennessee Valley and weak 
shortwave energy continues to traverse Georgia within the zonal 
flow pattern. We currently only expect isolated afternoon 
convection near the Altamaha River, with plenty of sunshine and 
lighter southwesterly low level flow allowing highs to reach the 
low to mid 80s inland, while the inland-moving Atlantic sea breeze
keeps coastal highs in the mid to upper 70s. Strong subsidence 
will keep dewpoints mostly in the 50s and will allow lows to fall 
back to the upper 50s inland and lower 60s at the coast on 
Thursday night. 

.LONG TERM [Friday Through Tuesday]...

Heights aloft will rise on Friday and Saturday as a previously 
closed upper low over the Desert Southwest ejects northeastward 
across the southern Rockies and the Plains States and deep-layered
ridging builds over the central and eastern Gulf of Mexico. 
Another frontal boundary will initially stall well to the north of
our area but will then begin to backdoor its way into southeast 
Georgia by late in the weekend as a strong surface ridge builds 
over New England. Long-term model blends continue to indicate 
isolated to widely scattered showers across southeast Georgia from
Sunday afternoon through Monday. Highs will soar to the mid 80s 
at most inland locations on Friday afternoon, with mid to upper 
80s this weekend for inland locations along and south of I-10 this
weekend. 

High pressure may begin to wedge into the southeastern states as 
soon as Saturday afternoon, which would produce enough of an 
easterly low level flow to keep highs in the mid to upper 70s this
weekend for locations north of Waycross, with onshore winds 
keeping coastal highs in the 70s as well. This wedge of strong 
high pressure may increase onshore winds enough early next week to
keep highs in the 70s throughout southeast GA, with low to mid 
70s for most coastal locations. Lows throughout the weekend will 
remain in the upper 50s to near 60 inland and the lower 60s at 
coastal locations. 

&&

.AVIATION...
[Through 06Z Wednesday]

VFR cigs (around 8000-12000 ft at times) will persist through 
this TAF period with very limited chance for any MVFR vsby or 
cigs. There may be a brief light shower/sprinkle today and 
tonight, but duration and intensity does not justify including in 
the TAF at this time. Light and variable winds early today will 
become south-southeast at 5-10 kt today.

&&

.MARINE...

Sfc ridge is just north of the area with sfc winds south-southeast
near 10-15 kt or less. Seas remain elevated about 4-7 ft per 
observations with most of the sea spectrum in the form of swells 
with periods around 14-15 seconds. Latest wave forecasts show some
seas of 6-7 ft over the offshore FL waters so extended the SCA 
until this afternoon. Winds will continue southerly into Wed then 
increase from the south-southwest as a weak low briefly forms 
north of the area. Light to moderate southerly winds to continue 
into Thu and Fri as the ridge axis remains to our south. A weak 
front may move into the GA waters during the weekend.

&&

.FIRE WEATHER...

Light south-southeasterly transport winds early this morning will 
shift to south-southwesterly with increasing speeds for inland 
southeast Georgia this afternoon, while lighter southerly transport
winds prevail elsewhere. The Atlantic sea breeze will shift southerly
winds sustained around 10 mph to southeasterly at 10-15 mph at 
coastal locations this afternoon. Transport winds will shift to 
southwesterly on Wednesday morning, with speeds increasing throughout 
inland southeast Georgia that will create high dispersion values. 
Lighter south-southwesterly surface and transport winds will prevail 
for inland northeast and north central Florida on Wednesday, with an 
afternoon sea breeze moving through coastal locations. Minimum 
relative humidity values will fall to the around 35 percent at inland 
locations by Thursday afternoon as highs climb into the mid 80s.  

&&

.HYDROLOGY...

Moderate flooding continues along the Altamaha River in southeast
Georgia. Moderate flooding has also developed along portions of 
the Satilla River near Waycross. These rivers will remain in flood
through this week. Everett City will approach it's record high 
through mid week.

&&

.PRELIMINARY POINT TEMPS/POPS...

AMG  75  56  80  57  81 /  20  10  20  30  10 
SSI  71  58  73  59  73 /  10  10  20  10  10 
JAX  77  57  82  58  82 /  10  10  10  10  10 
SGJ  74  58  78  59  78 /  10  10  10  10  10 
GNV  78  57  82  55  83 /  20  10  10  10  10 
OCF  79  57  82  55  84 /  10  10  20  10  10 

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late tonight for Coastal Flagler-
     Coastal St. Johns.

GA...None.
AM...Small Craft Advisory until 3 PM EDT this afternoon for 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.

&&