Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jacksonville Florida
240 am EST sun Nov 23 2014
..widespread rainfall this morning...
..Slight risk of severe storms this afternoon and evening over
the Suwannee Valley and southeast Georgia...
Short term...today and tonight...rain has overspread the area as
isentropic lifting increases. Isolated thunder possible this
morning as weak elevated instability develops. Upper short wave
trough now over Texas will move NE today with warm front lifting
north of southeast Georgia by midday. Expect precipitation to become more scattered
this afternoon as area will be in the warm sector. Models show
upper trough lifting into the southeast and developing a line of
convection into our western zones around 00z. Scattered convection
may develop ahead of this line this afternoon with strong/severe
storms possible as models show adequate instability and shear.
Strong winds and isolated tornadoes will be possible. Storm Prediction Center slight
risk area is over mainly the Suwannee Valley of North Florida and southeast Georgia.
Convection will weaken early tonight as lift and instability
weaken. Temperatures will remain above normal today and tonight
with gusty south winds.
Monday through Tuesday...a cold front will move from the central
Gulf Coast early Monday to southeast Georgia Monday aftn/evening. With upper
support ejecting to the Great Lakes states...the front will slow
down as the middle/upper flow become nearly parallel to the surface
front...with the boundary stalling across central Florida Tuesday
as a wave of low pressure develops along the front. Think the
greatest chance of precipitation early Monday will reside across interior
southeast Georgia along a pre-frontal trough...with not much in the way of
precipitation across the bulk of NE Florida. Will use chance probability of precipitation by Monday afternoon
for most areas as a middle level impulse crosses the area. Precipitation
coverage will increase late Monday night/early Tuesday as the
front enters the region. Scattered/numerous showers and isolated
thunderstorms will be possible Tuesday with the front just to the
south...and a wave of low pressure developing resulting in some
overrunning precipitation. With the greatest middle level dynamics exiting
the region...do not expect strong/severe thunderstorms. Expect additional
areal average rainfall of one half to one inch. Warm air will
surge Monday ahead of the cold front..resulting in highs mainly in
the upper 70s/lower 80s. Significantly cooler conditions will
prevail Tuesday in the wake of the cold front with highs in the
Lower/Middle 60s for most locations.
Long term /Tuesday night through Saturday/...
precipitation will linger across the area Tuesday night into Wednesday
until a kicker shortwave crosses the area which will dry the
region out as it ejects NE by Wednesday night. Will retain
mainly likely probability of precipitation into Wednesday...with a decreasing trend
Wednesday afternoon...with all areas dry Wednesday night. Rather chilly
conditions will prevail with lows Tuesday night in the 40s
with middle/upper 50s for highs Wednesday. Cool and dry conditions
will prevail for Thanksgiving day beneath sunny skies...with highs
generally in the lower 60s. Lows inland will fall into the 30s on
Thursday night...with 40s at the coast. Dry conditions will
continue Friday/Saturday with a slight moderation in temperatures
with surface high pressure over the region.
Aviation...rain should become widespread after 08z with MVFR ceilings
expected and thunderstorms in the vicinity as strong overrunning spreads over the area.
Warm front and rain should lift north of the area by midday with
precipitation becoming more scattered this afternoon/evening. Have
thunderstorms in the vicinity/vcsh after 16z for NE Florida tafs and after 18z for ssi. Southeast winds
will veer to the south and increase with gusts 20-25 knots by
early afternoon. Have low level wind shear in forecast until warm front lifts
north of the area.
Marine...wind speeds have decreased below advisory levels but expect
this lull to increase again to 20-25 knots this morning. Will keep
advisory and add occasional gale force gusts to offshore Georgia waters
today. Southeast winds will veer to the south today as warm front lifts
north. Winds and seas will start to decrease tonight with winds
becoming offshore. Cold front will move across the waters Monday
night and stall just southeast of the waters. Advisory conditions
possible again Tuesday and Wednesday.
Rip currents: high risk today becoming moderate on Monday as winds
become offshore. Breakers today will be 4 to 6 feet.
Preliminary point temps/pops...
amg 73 65 77 50 / 100 70 40 20
ssi 73 66 76 56 / 100 70 40 30
jax 78 66 81 55 / 100 50 50 40
sgj 79 68 79 58 / 90 40 50 40
gnv 79 65 79 55 / 80 50 50 40
ocf 82 66 81 58 / 60 50 50 40
Florida...high rip current risk through this evening for Duval-Flagler-
Georgia...high rip current risk through this evening for coastal Camden-
Am...Small Craft Advisory until 10 am EST Monday for Altamaha Sound
Georgia to Fernandina Beach Florida 20 nm to 60 nm offshore-
Fernandina Beach to St Augustine Florida 20 nm to 60 nm offshore-
St Augustine to Flagler Beach Florida 20 nm to 60 nm offshore.
Small Craft Advisory until 7 PM EST this evening for Altamaha
Sound Georgia to Fernandina Beach Florida out 20 nm-Fernandina Beach
to St Augustine Florida out 20 nm-St Augustine to Flagler Beach
Florida out 20 nm.