Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 031255

Area Forecast Discussion
National Weather Service Jacksonville FL
855 AM EDT Wed Jun 3 2020


High clouds continue to spread over forecast area ahead of weak
shortwave over eastern Gulf of Mexico. Low-level moisture return
will occur across northeast FL Today and southeast GA Tonight and
Thursday. As shortwave moves slowly eastward, model guidance
suggests a few showers/isolated t-storm will develop over our
southernmost counties late this afternoon, with showers increasing
and spreading northward Tonight and Thursday, as currently
forecast. Only minor tweaks to forecast in update. Current high
temperature forecast for Today looks fine.


[Through 12Z Thursday]

High clouds expected over TAF sites Today. Late in the day, may see
a few SHRA/TSRA approach KGNV/KSGJ from the south. Scattered showers
spread northward over TAF sites later Tonight, with potential for
MVFR Cigs after about 08z. Easterly surface winds 10 kts Today.



High pressure will move east of the area waters today into
Thursday with a chance of thunderstorms returning tonight through
the weekend as deep tropical moisture returns to the area.



.NEAR TERM [Through Tonight]...

Weak upper ridging extended from the Bahamas northwestward along
the Florida east coast and into the Southeast. The upper ridge
will shift eastward today as a weak mid level low/upper level
energy over the northeastern Gulf lifts east northeastward into
the Florida peninsula late this afternoon and early evening. Very
dry conditions were observed across the area early this morning
with precipitable water values (PWATS) of 0.8-1.3 inches, lowest
along the coastal counties. Deep tropical moisture will lift
northward in the southerly flow, with PWATS surging to 2+ inches
south of a line from Gainesville to St. Augustine by the early
evening. Cloud cover will increase throughout the day as well,
with mostly cloudy to cloudy skies expected across the area by the
mid afternoon. The deep moisture will continue to surge northward
tonight across the area. Rain chances will increase from south to
north this afternoon, with showers and a couple embedded
thunderstorms likely by the late afternoon across Marion County.
Showers are likely south of the I-10 corridor overnight tonight,
with a chance northward south of Waycross. Highs will be in the
upper 80s to near 90 across the interior and the low to mid 80s at
the beaches. Overnight lows will be in the upper 60s to around 70

.SHORT TERM [Thursday Through Friday]...

Thursday, a weak southern stream trough will move east into the
region Thursday over increasing low level moisture from the
south. The trough will promote synoptic lift over NE FL and SE GA
with likely showers becoming widespread as the day wears on. As
mid level vorticity rotates over the area on Thursday, a chance of
thunderstorms will be possible despite overall weak surface
instability being on the low side of less than 500 J/kg due to
abundant cloud cover and cooler than average temperatures.

On Friday, low level flow will become southwesterly underneath
unstable mid level southwest flow and surface instability will
increase northward into SE GA creating the opportunity for
scattered thunderstorms during the afternoon as temperatures
become warmer despite continued abundant cloud cover. However, at
this time the atmosphere does not appear to support severe
thunderstorm potential given weak shear and warm 500 mb
temperatures near -7 degrees Celsius, but a few of the storms
could produce some strong winds of 40-50 mph with instabilty
increasing to 1,500 to 2,000 J/kg by the afternoon hours. With
slower storm motions and high Precipitable water levels near 2.25
inches, there could also be a potential for locally heavy rainfall
from storms as uniform flow in the lower and mid levels could
allow storms to train over the same areas. Light southeast surface
winds veer to southerly through the day.

High temperatures on Thursday will be cooler than average near 80
degrees along the coast and into the low 80s inland. Lows on
Friday will be near seasonal in the upper 60s to near 70 inland
with low 70s over coastal areas. Highs on Friday will warm into
the mid 80s over SE GA with low 80s over NE FL.

.LONG TERM [Saturday Through Wednesday]...

Tropical Storm Cristobal is forecast by the National Hurricane
Center to move northward from the Yucatan Peninsula into the
central Gulf of Mexico Saturday, but is not expected to approach
our area. Even so, deep tropical moisture over the southeast Gulf
of Mexico will move northward into the eastern Gulf of Mexico Gulf
around the storm`s circulation and will begin to spread into the
the western FL Peninsula. The GFS and ECMWF model trends bring
some of the heaviest rainfall activity over western portions of
our area Sunday into Monday. Heavy Rains over the eastern Gulf of
Mexico and a few isolated storms will encroach over the Florida
Panhandle and Gulf coast by Saturday evening and then into the
Suwannee Valley of NE FL Saturday night.

Sunday, the heavy rainfall will spread northeast into the rest of
NE FL and into inland SE GA areas mainly south of Waycross. Some
veering winds from the low levels into the mid levels on Sunday
will also present a potential for some strong to severe
convection embedded in the waves of heavy rain showers as
southwest mid level flow rides over southerly enhanced winds
around 30 to 40 knots while surface winds remain southeasterly
during the day.

Monday into Tuesday, low level southerly flow will relax and
diurnal storm activity will persist over the region as Tropical
Storm Cristobal moves well northwest of our area. However, deep
tropical moisture and diurnal thunderstorm activity will keep a
potential for more heavy rainfall over the area. Several inches of
heavy rainfall are possible into Tuesday over the region with
WPC`s extended range rainfall guidance still indicating rainfall
totals of up to 5-7 inches over NE FL and inland SE GA with 3-5
inches over coastal SE GA through early next week.

Wednesday, a backdoor cold front will move southward down the east
coast towards the Georgia coast as a mid level ridge moves
southeast from the Great Lakes into the Mid Atlantic region.
Surface high pressure will move southward along the Atlantic
waters off the east coast of the U.S. and bring a chance for
scattered showers moving onshore from the atlantic as the backdoor
cold front approaches from the northeast.

Temperatures during this period will feature near seasonal high
temperatures in the mid 80s this weekend Saturday and Sunday
with with a warming trend Monday through Wednesday of next week.
Overnight lows will remain in the low 70s through Wednesday.



AMG  89  70  83  69  84 /   0  20  60  40  70
SSI  84  72  81  72  83 /   0  30  70  60  70
JAX  87  70  82  71  85 /  10  40  80  60  70
SGJ  84  69  81  70  83 /  20  60  90  70  80
GNV  87  69  80  69  83 /  30  70  90  60  80
OCF  87  69  81  70  84 /  60  80 100  70  90


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