FXUS62 KJAX 221850
Area Forecast Discussion
National Weather Service Jacksonville FL
250 PM EDT Tue Aug 22 2017
.NEAR TERM /Tonight-Wednesday/...
High pressure will be to the East of NE FL this afternoon, with weak
troughing over SE GA. The subsidence under the ridge will limit
convective potential over NE FL, but will continue to see
development over SE GA. Convective activity will dissipate around
sunset with the loss of diurnal heating. Low level moisture inland
could result in fog over inland areas again Overnight. Region will
be between high pressure ridge to the Southeast and a trough
approaching from the North. Expecting a weather scenario on
Wednesday that is very similar to Today, with subsidence under the
ridge restricting convective potential over NE FL, while convergence
along trough provides focus for convection over SE GA. Temperatures
will trend above normal this period.
.SHORT TERM /Wed Night-Friday/...
Weakening cold front over the SE U.S. on Thursday will track into
SE GA/NE FL region by Friday. Scattered shower and thunderstorm
activity mainly during the afternoon and evening hours will become
more numerous on Friday. Even with the frontal boundary pushing
into the region steering flow will remain weak through the period
and expect locally heavy rainfall to remain the main threat due to
slow moving storms and interaction with Atlc Sea Breeze ability to
push inland both days. Relatively warm mid-level temps will
continue to suppress widespread severe storms but strong storms
with frequent lightning and gusty winds will remain possible
during the afternoon and evening hours. Max Temps will be well
into the lower to middle 90s on Thursday ahead of the front with
heat indices close to 105 degrees, while the slightly earlier
start and higher coverage of convection on Friday will hold Max
temps in the lower 90s inland and upper 80s at the coast with the
earlier onset of the Atlc Coast Sea Breeze. Total rainfall amounts
through Friday expected to range from 0.50-1.00" across NE FL and
1.00-1.50" across SE GA where the weakening frontal boundary will
focus slightly higher precipitation amounts.
.LONG TERM /Saturday-Tuesday/...
Long-range GFS/ECMWF models still in general agreement with
development of surface low development on the old frontal boundary
off the FL East Coast Atlc Waters this weekend and still some
question as to whether this would be tropical or subtropical
development and how strong it would be before approaching trof
would slowly kick it out to the NE over the Wrn Atlc early next
week. So local impacts across the region would likely be across
the Coastal Waters and immediate coastal counties with higher
rainfall chances and increase in onshore/Northeast flow through
the weekend into early next week. Inland areas especially SE GA
could see much less precipitation if drier airmass gets wrapped
around on the back side of any developing low pressure system off
the coast. So overall still much uncertainty with long range
forecast although some higher confidence in more abundant clouds
and cooler Max Temps only in the 85-90 degree range. Rainfall
forecast still uncertain with another inch or two of rainfall
possible through the extended time frame from the weekend into
early next week with some locally higher totals along the coast if
any organized convergent rain bands could form in the NE Flow.
Prevailing VFR conditions are expected this afternoon, except for
KSSI where isolated to scattered showers and storms are expected.
Inland fog is anticipated Overnight, with restrictions for KGNV and
KVQQ. Best chances for convection on Wednesday will be over SE GA.
High pressure will be East of area waters Tonight. This ridge will
sink to the South Wednesday as a trough of low pressure slides
down the Southeast US coast, reaching Southeast Georgia waters
Thursday. This trough will linger over area waters into Friday.
Low pressure could develop over the region this weekend, possibly
resulting in elevated conditions.
Rip Currents: Moderate Risk.
.PRELIMINARY POINT TEMPS/POPS...
AMG 74 93 75 93 / 30 40 40 50
SSI 76 91 78 90 / 20 30 30 50
JAX 74 93 75 93 / 10 20 20 50
SGJ 76 93 76 91 / 10 20 20 40
GNV 73 94 74 94 / 10 20 20 50
OCF 73 94 74 93 / 10 20 20 50
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