Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Jacksonville Florida
439 am EDT Mon Sep 16 2019
..hazardous surf and rip currents continue this week...
as tc Humberto slowly pulls away from the area and prevailing
winds become more northerly, drier conditions expected today but
still a low chance of coastal showers for the coastal counties
through the better portion of the day. Due to more sun, Max temps
will push through the lower 90s inland and upper 80s at the
coast. Winds not as high over the eastern zones as prior days as
gradient weakens but expecting breezy conditions of 15-20 mph with
a few gusts to 30 mph. Winds generally 10-15 mph further inland
today. Becoming mostly clear for most areas tonight with lows a
bit lower due to lower dewpoints. Any shower activity will likely
remain over the coastal waters as deep moisture continues to shift
eastward with tc Humberto. Main local hazard is the surf and rip
current problem today and will likely be a hazardous issue the
rest of the week.
Short term...Tuesday through Wednesday...
Hurricane Humberto will continue to slowly move off to the
northeast, keeping low level winds slightly elevated on Tuesday,
particularly along the coast. A much drier air mass will push into
southeast Georgia & NE Florida on Tuesday, with precipitable water values falling below 1.5"
across the area and minimum surface relative humidity values around 35% in inland
portions of the area. It will be drier, but not cooler. Afternoon
temperatures will peak in the mid 90s on Tuesday and overnight,
temperatures will stay in the low-mid 70s. Low level flow will
become more easterly on Wednesday, bringing a return flow of
moisture at least near the surface. This will also mean a return
of scattered showers and isolated thunderstorms. Temperatures will
be slightly cooler, with highs in the low 90s and overnight lows
in the mid 60s across inland southeast GA, upper 60s to low 70s
Long term...Thursday through Monday...
By Thursday, the area will be situated under the eastern periphery of
the mid and upper levels ridges and on the southeast side of the
low level ridge. This deep layer ridging will slowly build
eastward through the weekend. On Sunday, a +pv anomaly will swing
through the upper level trough to our northwest, amplifying it as
it moves into the Great Lakes region. This will develop a cold
front that will sweep towards the southeastern US on Monday. The
upper level anomaly driving this system is poised to lift off to
the northeast Monday night, however, so this front will likely
stall out and dissipate to the north of our area. Persistent low
to mid level easterly flow from this pattern is more likely to
bring scattered showers and isolated storms to the area than the
front at this time. Still, temperatures will be cooler over the
weekend and early next week with highs mostly in the upper 80s and
lows in the mid-upper 60s.
Sct-broken cumulus will continue to affect the coastal tafs through
the mid morning hours, with periods of MVFR cigs expected. Further
inland for gnv, more scattered cumulus deck expected today. A low
chance of a brief shower that may cause some MVFR vsby into midday
but otherwise rain chances are much lower today than the prior
couple of days. Expecting more prevailing VFR after mid afternoon
as drier air filters into the area. However, sgj may continue to
see sct-broken cumulus mid afternoon into the late evening hours
as northerly flow brings in stratocu off the warm Atlantic waters.
North to northeast winds will increase again to about 15g22kt
after sunrise...decreasing to near 10 kt or less this evening.
Winds and seas remain rough and hazardous and based on latest
data and guidance have extended advisories a bit longer. Winds at
sauf1 were 22 kt and seas at St Augustine buoy were 7-8 ft. Most
of the wave energy is composed of strong swells in the 8 to 11
sec period range. While winds may relax a bit tonight and Tuesday,
seas will remain hazardous for small boaters. Then, as a backdoor
front/trough pushes through on Wed, winds and seas will pick up
again. Swells from Humberto should also continue to affect area
waters through late this week.
Rip currents: high risk of rip currents and high surf expected to
continue across area beaches. Latest readings show seas of 6 to
near 8 feet which suggests surf may be 5-7 ft for for northeast
Florida beaches and a bit lower for southeast Georgia.
Coastal flood statement issued this morning for elevated water
levels at several sites with at least a couple of locations
flirting with minor flooding criteria. These higher levels were
noted at Satsuma and bings Landing. The elevated water levels may
continue to occur for a good portion of this week, due to the
prevailing northerly-northeast winds and recent full moon. For
most part looks like majority of water measuring stations remain
below minor flooding in the near term period.
Hurricane Humberto will slowly move northeastward away from the
area, but its proximity to US will mean the continuation of
breezy conditions. Elevated winds will lead to high dispersions in
NE Florida & southeast Georgia today and Tuesday. Drier air will work its way into
the area on Tuesday, with relative humidity values dropping to around 35% over
inland portions of our area. Red flag conditions are not
anticipated for the next several days.
Preliminary point temps/pops...
amg 92 69 95 71 / 0 0 0 0
ssi 89 75 90 76 / 20 0 0 10
jax 90 73 92 74 / 20 0 0 10
sgj 87 75 88 75 / 30 10 0 10
gnv 91 70 94 70 / 10 0 0 0
ocf 92 72 94 71 / 10 0 0 0
Florida...high rip current risk through late tonight for coastal Duval-
coastal Flagler-coastal Nassau-coastal St. Johns.
High surf advisory until 4 am EDT Tuesday for coastal Duval-
coastal Flagler-coastal Nassau-coastal St. Johns.
Georgia...high rip current risk through late tonight for coastal Camden-
Am...Small Craft Advisory until 4 am EDT Wednesday for waters from
Altamaha Sound Georgia to Fernandina Beach Florida from 20 to 60 nm-
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 nm.
Small Craft Advisory until 4 am EDT Tuesday for coastal waters
from Altamaha Sound to Fernandina Beach Florida out 20 nm-
coastal waters from Fernandina Beach to St. Augustine Florida
out 20 nm-coastal waters from St. Augustine to Flagler
Beach Florida out 20 nm.