Scientific Forecaster Discussion
fxus62 kjax 171457
Area forecast discussion
National Weather Service Jacksonville Florida
957 am EST sun Nov 17 2019
the coastal low is vertically stacked and moving very slowly
north-northeast away from the area. The back edge of the
925/850/700 mb troughs are situated over the a region with dense
stratus entrenched south and east of a line from Sapelo Island,GA
to Keaton Beach, Florida with the back edge very, very, very slowly
eroding. With thick stratus and decent cold air advection
well established am not really expecting diurnal heating to make
much headway on breaking up the low cloud deck other than over
interior southeast Georgia and the Suwannee Valley. So maybe we'll see some
breaks over the Jacksonville Metro area late this afternoon but
expect it will be closer to sunset before the status breaks up
over most of Florida.
In places like Douglas and Hazlehurst its going to be a mostly sunny
but chilly day with brisk northwest winds.
[through 12z monday]
With the lower level troughs over the region and cold air
advection wrapping around the coastal low going to be hard to
break up the low/dense stratus deck. Therefore will keep all of
the fields down in the 1.2 to 1.8 kft range rest of this morning
and bump up to 1.5 to 2.0 kft this afternoon.
Winds and seas continue in the Small Craft Advisory criteria over
the coastal waters today and will gradually diminish as the low
pulls away through Monday.
So far the most significant (minor) coastal flooding has been
observed on the St Johns River and suspect we will be close to,
but will fail a tad short of moderate coastal flooding along the
oceanfront with this coming high tide cycle. The wind has enough
of a northwesterly component to counteract the ekman pumping and
thus we are unlikely achieve those higher values.
Previous discussion [302 am est]...
Near term...today through tonight...intense surface low
pressure(999 mb) located well off the Georgia coast will slowly
move NE today with winds and cloudiness gradually decreasing
across our area. Cloudy skies this morning expected to decrease
from the west this afternoon as weak high pressure builds in.
Temperatures will still be below normal with highs today only in
the upper 50s and lower 60s. North northwest winds will be 10-15
mph with gusts around 20 mph near the East Coast. A mid level
shortwave trough will approach the area tonight. This will only
bring an increase in mid- high level cloud cover and possibly a
few sprinkles to se GA due to limited moisture and lift.
Short term...Monday through Wednesday...mostly dry conditions and below
normal temperatures this period as a couple re-enforcing but
generally dry cold frontal passages occur under a mean layer
eastern US trough through Tue. Cloud cover increases Mon as a
short wave trough and weak surface cold front pass east-southeast across the
local area, bringing only a low chance of a brief shower or
sprinkles across southeast Georgia through Mon afternoon as deep layer
moisture, forcing and instability will be lacking. Mon night into
Tue a long wave trough axis deepens across the eastern Gomex with
the surface front sliding offshore of the southeast Atlantic bight, north
of the local area as a surface ridge builds eastward across the
Gulf Coast states. This ridge will continue to edge eastward into
Wed and dominate over the local area Wed with dry conditions and
light winds as an upper ridge dampens aloft.
A cool deep layer north-northwest to west-northwest flow will continue below normal
temperatures. Low temperatures will range from near 40 inland to
around 50 along the coast. High temperatures will range about 5-10
deg below climo values from the low 60s across southeast Georgia to the
mid/upper 60s across NE Florida Mon & Tue then moderate into the
mid/upper 60s Wed as the ridge builds overhead.
Long term...Thursday through sun...
Dry conditions and a warming trend back near climo values as stacked
high pressure builds over the southeast region Thu. The surface ridge
builds offshore of the southeast Atlantic coast Fri as upper level flow
backs SW in advance of the next approaching frontal system. This
will warm temperatures above climo values into the mid/upper 70s.
There remains forecast model discrepancy regarding the timing and
structure of the next frontal system Fri-sun, but overall trend is
for increasing rain chances as long wave tough begins to carve
southward once again across the eastern Continental U.S. And sends more
moisture & forcing across the local area under west-southwest flow.
Preliminary point temps/pops...
Amg 58 43 65 42 63 / 0 10 0 0 0
ssi 58 47 65 47 64 / 10 10 10 0 0
jax 61 45 67 45 65 / 0 10 0 0 0
sgj 61 49 67 49 66 / 10 10 0 0 0
gnv 62 45 67 45 65 / 10 10 0 0 0
ocf 64 47 70 47 67 / 0 0 0 0 0
Florida...coastal Flood Warning until 4 PM EST this afternoon for coastal
Duval-coastal Flagler-coastal Nassau-coastal St. Johns.
High rip current risk until 7 PM EST this evening for coastal
Duval-coastal Flagler-coastal Nassau-coastal St. Johns.
High surf advisory until 4 PM EST this afternoon for coastal
Flagler-coastal St. Johns.
Coastal flood advisory until 5 am EST Monday for Clay-inland
Duval-inland Flagler-inland Nassau-inland St. Johns-Putnam.
Georgia...coastal flood advisory until 4 PM EST this afternoon for coastal
Camden-coastal Glynn-inland Camden.
Am...Small Craft Advisory until 9 PM EST Monday for waters from
Fernandina Beach to St. Augustine Florida from 20 to 60 nm-
waters from St. Augustine to Flagler Beach Florida from 20 to 60
Small Craft Advisory until 10 am EST Monday for coastal waters
from Fernandina Beach to St. Augustine Florida out 20 nm-coastal
waters from St. Augustine to Flagler Beach Florida out 20 nm-
waters from Altamaha Sound Georgia to Fernandina Beach Florida from
20 to 60 nm.