Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 162001
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
400 PM EDT Wed Aug 16 2017

.NEAR TERM...

Rest of this afternoon into Tonight...Widely scattered stratiform
showers in the wake of earlier convection west of Flagler county.
Continued isolated convection this late afternoon across portions of
eastern Flagler county due to NWLY steering flow keeping widely
scattered showers and isold convection. This activity will quickly
wane before sunset, with fair skies expected for most locations
throughout the night. The retrograding ridge aloft overnight will
result in a slight cooling in temperatures aloft during the predawn
hours along the Atlantic coast, and some isolated convection may
begin to develop in the coastal counties towards sunrise on
Thursday. A light westerly low level flow and plenty of low level
moisture will keep lows in the mid/upper 70s inland and near the
precipice of 80 at area beaches.

Thursday...TUTT cell pushes westward across Cuba with no affect
across our region. Ridge aloft retrogrades Westward over the central
Gulf coast near Louisiana which will open the door for troughing to
build in from the SE aloft. Mid levels will be slow cool with 5h
temps will remain at -5 to -6 with less subsidence in place. There
will be afternoon and evening hours as PWATS remain between 2 and
2.2". Afternoon and evening storm coverage increases back into the
60-80% range across NE FL / 35-55% across southeast Georgia as
steering flow veers back to the W with storm motion moving towards
the E. Slightly higher coverage of storms will knock the temps down
a couple of degrees, particularly NE FL but still expect high temps
into the lower to middle 90s inland and near 90-92 along the coast
with heat Indices around 105 degrees.

.SHORT TERM...
Thursday night... Lingering isolated to scattered showers and storms
expected through the evening hours, but guidance shows some
convection is still possible after midnight. Have left in isolated
coverage after midnight...with support from abundant moisture and
weak sfc trough from coastal GA to the FL big bend area. Lows mostly
in the mid to possibly upper 70s.

Friday...sfc ridge will drop a little south and upper levels suggest
more of col region developing. Sfc troughing will extend from the
Appalachians southwest to the wern FL panhandle. PWATs just above 2
inches...slightly steeper lapse rates in the mid levels and sea
breezes will kick off sct to numerous showers and storms. Activity
will start in the morning and early afternoon given virtually no
CIN. Highs should still manage to reach around the lower 90s...and
given elevated dewpoints, heat indices should be able to reach
around 103 to 107 again. On Friday night...isolated to scattered
showers and storms expected that should wind down slowly. However,
persistent low level troughing just north of the area may allow some
convection to continue after midnight. Above normal lows again in
the mid to upper 70s.

Saturday...Mid level ridge will build back into our east/southeast
zones with some drier air advecting in from the southeast from the
western ATLC. Model blend guidance suggest higher POPS over the
southeast GA zones with less coverage in northeast FL. It`s possible
we`ll see only isolated coverage in northeast FL due to dry air
advection. Near to just above normal temps expected at this time.

.LONG TERM...Sunday-Wednesday...
Model continue to illustrate that mid level ridge will build in over
the area with heights rising. From Tuesday to Wednesday, however,
there`s continuity in the guidance of ridging aloft retrograding
through the Gulf of Mexico while mid/upper troughing develops
further over the eastern CONUS. This could help enhance rain chances
again but too soon to begin upping POPS. Model consensus POPs look
reasonable for now and was used showing generally 30-50 percent
chances and temps that are near or just above average. Steering flow
becomes south to southeast and along with development of ATLC sea
breeze making headway inland should allow for better chances inland
at least for Sunday and Monday.

&&

.AVIATION...VFR conditions will prevail through the overnight
hours with convection well south of terminals this afternoon and
evening. Calm to light drainage winds expected overnight. Light
westerly winds expected over the region Thursday. Scattered to
numerous showers and storms from mid morning to late afternoon with
deep moisture across the area. Terminals may experience brief MVFR
cigs and perhaps gusty winds with some stronger storms with TEMPO
TSRA mentioned later in the TAF period.

&&

.MARINE...An eastward extension of Atlantic ridging will expand into
the southeastern Gulf of Mexico and will lift northward through
Friday. This weather pattern will maintain a light offshore wind
flow, with our local pressure gradient loosening enough to allow the
Atlantic sea breeze to develop near the coast during the mid
afternoon hours through Friday. South-southwesterly evening wind
surges will bring wind speeds up to near 15 knots in the offshore
waters each evening through Friday. Atlantic ridging will build
northward this weekend, with prevailing southerly winds expected on
Saturday and then southeasterly winds by Sunday afternoon. The
Atlantic sea breeze will develop earlier in the afternoon at the
coast this weekend. A southerly wind surge on Saturday evening may
bring winds into the caution range of 15-20 knots, but speeds will
otherwise remain below caution through the weekend, with seas
remaining in the 2 to 4 foot range.

Rip Currents: Offshore winds, low wave heights of 1 to 2 feet, and
the outgoing tide late this afternoon should equate to a low risk. A
low risk will likely continue through Saturday with light winds and
seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  77  95  76  94 /  10  40  20  50
SSI  79  91  79  91 /  10  50  20  50
JAX  77  93  76  92 /  10  60  20  60
SGJ  77  91  77  91 /  20  80  30  40
GNV  75  92  75  91 /  10  80  20  50
OCF  76  92  75  91 /  10  80  20  50

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

$$

Cordero/Shashy/Shuler


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