822 
FXUS62 KJAX 072258
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
558 PM EST Thu Nov 7 2019

...STRONG COLD FRONT MOVES THROUGH OUR REGION LATE TONIGHT AND 
FRIDAY MORNING... 
...RAINY AND CHILLY CONDITIONS THROUGHOUT NORTHEAST AND NORTH 
CENTRAL FLORIDA ON FRIDAY...

.CURRENTLY...

Early evening surface analysis depicts weakening high pressure 
(1023 millibars) moving off the southeast U.S. coast ahead of an 
arctic cold front that extends from New England southwestward 
through the Appalachians and into the lower Mississippi Valley. 
Strong high pressure (1038 millibars) was building over the Plains
and Great Lakes in the wake of this front. Aloft...ridging 
continues to flatten over the southern Gulf of Mexico as a broad 
trough digs southward from the Plains and Great Lakes states. A 
stubborn stratus deck along and north of the U.S. Highway 84 
corridor in southeast Georgia is finally eroding from south to 
north as warm air advection strengthens in advance of the 
approaching cold front. A few brief showers developed along the 
inland moving Atlantic sea breeze boundary earlier this afternoon 
over the St. Johns River basin, but dry conditions otherwise 
prevail across most of our region. Highs reached the low to mid 
80s throughout northeast and north central Florida this afternoon,
with lower 70s prevailing for locations north of U.S. Highway 84 
that have been beneath the persistent stratus deck today. 
Dewpoints at 22Z range from the mid to upper 60s across southeast 
Georgia to the upper 60s and lower 70s elsewhere. 

.NEAR TERM [Through Friday]...

Latest short-term, high resolution guidance indicates that the
arctic cold front will approach the Altamaha and Ocmulgee River
basins around midnight, with showers and a few embedded
thunderstorms overspreading southeast Georgia through the predawn
hours. The front will move across the Interstate 10 corridor just
before sunrise, with showers and a few embedded thunderstorms
overspreading northeast Florida during the early morning hours,
while post-frontal light rainfall continues over southeast
Georgia. Temperatures will remain in the 60s and 70s overnight
ahead of the front area-wide, followed by falling temperatures
during the predawn hours in southeast Georgia, where lower 60s are
expected around sunrise as winds shift to north-northwesterly and
become breezy. Lows will only fall to the upper 60s or lower 70s
for most of northeast and north central Florida. 

Strong high pressure will shift southeastward over the the Ohio 
and Tennessee Valleys on Friday as it expands southward into our 
region, resulting in a tightening local pressure gradient and 
windy conditions developing along the I-95 corridor by the 
afternoon hours as winds gradually shift to north-northeasterly. 
Post- frontal light rainfall will exit southeast Georgia from 
north to south from the late morning through the mid-afternoon 
hours, with widespread rainfall persisting east of U.S. Highway
301 into the afternoon hours, with coverage eventually shifting
south of I-10 towards sunset. Strong cold air advection will
result in slowly falling temperatures area-wide throughout the
day, with readings in the 50s by late afternoon throughout
southeast Georgia and the lower 60s elsewhere. Sustained north-
northeasterly winds will increase to 20-30 mph along the northeast
Florida coast by late afternoon, and a Wind Advisory may be
required along the I-95 corridor in northeast Florida through the
early to mid evening hours as our local pressure gradient
continues to tighten. Steadier rainfall should shift south of St.
Augustine by sunset.

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

High pressure will gradually weaken as it expands across the
southeastern states by late Friday night and Saturday. Steadier
post-frontal rain should shift south of Flagler County by 
midnight Friday night, with light rain or drizzle gradually 
concluding overnight along the I-95 corridor in northeast Florida.
Cold and dry air will filter into southeast Georgia overnight as 
skies clear out from north to south during the early evening 
hours. Clearing skies will be slower to reach I-10, with cloudy 
skies prevailing overnight for locations south of I-10. A light 
northeasterly breeze will likely continue overnight for inland 
locations, and lows will fall to the upper 30s from Waycross 
northward, creating near freezing wind chills for these locations 
towards sunrise. Lows will fall to the 40s elsewhere along the 
I-10 corridor and for coastal southeast Georgia, with breezy 
onshore winds keeping coastal lows in the 50s to around 60 in 
northeast Florida.

Skies will clear our for locations south of I-10 on Saturday
morning as cool high pressure settles over Georgia. Our local
pressure gradient will gradually loosen but will remain tight
enough to keep breezy northeasterly winds in place throughout
northeast and north central Florida. Despite plenty of sunshine, 
highs will range from near 60 along the Altamaha/Ocmulgee Rivers
to near 70 in north central Florida. Winds will decouple at inland
locations on Saturday evening, setting the stage for another cold
night, especially over southeast Georgia, where lows will bottom
out in the upper 30s north of Waycross. Lows will fall to the 40s
elsewhere inland, with a light northerly breeze keeping lows in
the 50s over north central and coastal northeast Florida. 

Broad troughing will push eastward off the Atlantic coast by
Sunday morning, with zonal flow aloft developing over our region
as weakening high pressure shifts eastward off the Carolina coast.
A dry air mass and mostly sunny skies will allow highs to rebound
to near 70 across southeast Georgia and the 70s throughout
northeast and north central Florida. Surface winds will likely
decouple early on Sunday evening, but veering low level flow and
some thin cirrus advecting into our region will keep lows in the
40s for inland locations north of I-10, with 50s elsewhere and
lower 60s along the northeast Florida coast.

.LONG TERM [Monday Through Thursday]...

A more powerful trough will dive southeastward from the northern
Rockies and Upper Midwest on Monday morning, reaching the U.S.
eastern seaboard by late Tuesday night. Latest long-term guidance
indicates that the arctic cold front associated with this digging
trough will push across southeast Georgia on Tuesday morning and
the rest of our region on Tuesday afternoon. Models remain in
disagreement on whether deep moisture will advect northeastward
from the Gulf of Mexico over our region ahead of this front, with
the latest operational GFS maintaining a drier solution, while the
latest ECWMF develops another widespread post-frontal event
similar to what will occur tomorrow. Despite increasing mid and
high cloudiness on Monday, temperatures will rebound well into the
70s area-wide, with a few 80 degree readings possible over north
central Florida. Lows should remain in the 50s inland and the 60s
along the coast ahead of the front on Monday night, with most of
the potential shower activity arriving early on Tuesday along the
frontal boundary. Temperatures should reach the 70s in northeast
and north central Florida on Tuesday morning before the front
moves through, with falling temperatures on Tuesday afternoon over
southeast Georgia. Lows will plunge into the 30s across inland
southeast Georgia on Tuesday night, and highs will only reach the
50s across most of our region in the wake of the next frontal
passage on Wednesday. A light freeze appears possible by Wednesday
night/early Thursday morning for inland southeast Georgia as an
arctic dome of high pressure expands over the southeastern states,
with highs remain in the 50s on Thursday in southeast Georgia and
the 60s in northeast and north central Florida.  

&&


.MARINE...

A strong cold front will approach the Georgia waters towards
midnight. Numerous showers and a few embedded thunderstorms will
overspread the Georgia waters after midnight as the cold front
pushes southward into the Florida waters towards sunrise.
Northwesterly winds will strengthen towards sunrise over the
Georgia waters as numerous showers and a few embedded
thunderstorms overspread the northeast Florida waters during the
early morning hours. Arctic high pressure will build into the
Tennessee and Ohio Valleys on Friday afternoon as the front moves
south of the northeast Florida waters. Strong northerly winds will
overspread our waters during the morning hours on Friday, with
Gale Force wind gusts possible during the afternoon and evening
hours. Seas near shore should peak in the 6-9 foot range on 
Friday night and early Saturday morning for the northeast Florida 
waters, with 9-12 foot seas offshore. Northeasterly winds will 
begin to diminish on Saturday afternoon as high pressure gradually
weakens over the southeastern states. Winds and seas should fall 
below Small Craft Advisory levels by early Sunday. Seas should
fall below Caution levels on Sunday afternoon. The next strong 
cold front is slated to pass through our waters on Tuesday 
evening.

&&

.FIRE WEATHER...

Showers and embedded thunderstorms will overspread southeast
Georgia after midnight, followed by strengthening north
northwesterly surface and transport winds during the predawn 
hours. Showers and embedded thunderstorms will reach the
Interstate 10 corridor during the predawn hours, with
strengthening northerly surface and transport winds expected
during the morning hours across northeast and north central
Florida. Rainfall will continue through Friday evening across
coastal northeast Florida, with strong northeasterly surface and
transport winds expecting Friday afternoon and night. A cooler 
and drier air mass will filter over southeast Georgia on Friday
night and Saturday, with minimum relative humidity values falling
to the 30-35 percent range on Saturday afternoon across inland
portions of southeast Georgia on Saturday afternoon. 

&&

.PRELIMINARY POINT TEMPS/POPS...

AMG  61  64  38  60  39 /  70  40  10   0   0 
SSI  64  65  48  62  49 /  70  60  10   0   0 
JAX  68  69  49  66  48 /  60  70  30  10   0 
SGJ  70  71  58  69  57 /  60  70  50  10   0 
GNV  69  71  50  70  49 /  30  40  40  10   0 
OCF  68  74  57  71  52 /  30  40  40  10   0 

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...Small Craft Advisory from 1 PM Friday to 1 PM EST Saturday for 
     Coastal waters from Fernandina Beach to St. Augustine FL 
     out 20 NM-Coastal waters from St. Augustine to Flagler 
     Beach FL out 20 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.

     Small Craft Advisory from 7 AM Friday to 1 PM EST Saturday for 
     Coastal waters from Altamaha Sound to Fernandina Beach FL 
     out 20 NM-Waters from Altamaha Sound GA to Fernandina Beach 
     FL from 20 to 60 NM.

&&