Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 161800

Area Forecast Discussion
National Weather Service Jacksonville FL
156 PM EDT Fri Apr 16 2021

[Through 18Z Saturday]

Areas of rain and embedded t-storms are moving into the FL big bend
area at 18Z today. Some of the shower activity fades with eastern
extent through northeast FL. However, as the impulse upstream moves
though the region and the airmass continues to moisten, we expect
these showers to begin to impact the TAF sites after 20Z, with
periods of MVFR vsby anticipated at times. The showers will mainly
affect northeast FL TAFs first but will eventually go through SSI
with more stratiform type rain showers since they are well north of
the quasi-stationary front over north central FL. Best chance of t-
storms still appears to GNV later this aftn with lower chances
further east and north into the JAX metro TAFs. MVFR ceilings looks
likely for tonight, mainly over northeast FL. A lull in convective
activity looks on track by late evening, but another round of
convection possible late tonight and Saturday morning, but a bit
tricky forecast given the changing model solutions. Just kept in
PROB30 group for now 08Z through about 15Z Saturday with lower
ceilings to IFR.



.NEAR TERM [Through Tonight]...

Slow/southward moving frontal boundary will stall across North
Central Florida later today and will set the stage for the
upcoming wet pattern this weekend. This morning a few light
showers will be possible as the front settles into North Florida
then first impulse tracks along the boundary from the NE Gomex and
brings increasing shower activity across NE FL this afternoon with
a few embedded thunderstorms that could become strong to isolated
severe with gusty winds and hail, mainly south of a line from
Gainesville to St Augustine. Most of SE GA remains dry with just
a few isolated showers returning there during the afternoon hours.
With abundant cloud cover today not expecting much rebound in
temps from current 60s this morning, only into the lower to middle
70s for most locations this afternoon. A brief lull in shower
activity is expected this evening before the next impulse moving
along the Northern Gulf Coast starts to increase shower activity
after midnight across inland SE GA and inland NE FL with embedded
storms towards morning that may once again contain strong enough
elevated cores to produce hail, gusty winds and locally heavy
rainfall. Mild overnight lows in the 50s/60s.

.SHORT TERM [Saturday Through Sunday Night]...

Ongoing widespread showers and embedded strong to isolated severe
storms Saturday morning area-wide will see a brief lull in
activity late Saturday before picking back up late Saturday Night
into Sunday and shifting more to a mostly NE FL rainfall event
through Sunday Night. By now rainfall totals will begin adding up
into the 1 to 3 inch range with heaviest totals expected across NE
FL and while most of this is beneficial rainfall to make up for
some spring rainfall deficits and defer the start of the local
wildfire season, these totals may start to produce some localized
flooding issues in mainly urban areas of NE FL. Max Temps will be
held in check due to cloud cover/rainfall and mainly in the 70s
and Min temps still in the 50s/60s. Still too early to determine
exact positioning of isolated severe weather threat as elevated
storms with hail threat could be either in SE GA or NE FL, while
the better chance for surface based storms with gusty wind threat
will remain further south across NE FL at this time.

.LONG TERM [Monday Through Thursday]...

Monday/Tuesday...Still details to work out but overall long range
models in decent agreement that front will sag southward on Monday
while next stronger disturbance will develop on the front over the
Eastern Gomex Monday Night then track Northeast into NE FL on
Tuesday with best chance of significant heavy rainfall potential
for the entire event and whether Flood Watch needs to be posted
will depend on how much antecedent rainfall actually occurs this
weekend, but by this time a higher threat of urban flooding in
some portions of NE FL will exist along with potential river
flooding in the Santa Fe/Black Creek basins of NE FL. Lesser
amounts of rainfall expected across SE GA, while storm total
rainfall amounts over the next 5 days could be in the 4 to 6
inch range for section of NE FL south of the I-10 corridor. Max
temps remain below normal in the 70s due to cloud cover/rainfall
and lows still in the 50s/60s.

Wednesday/Thursday...Drier airmass filters into the region behind
the departing system and while temps will reach close to 80 Wed
afternoon, a secondary cold front Wed Night will drop lows back
into the 40s/50s by Thu morning and highs only rebounding back
into the 70s under Sunny skies and cool/breezy Northeast winds as
High pressure builds into the GA/Carolinas.


No headlines are expected through early next week as frontal
boundary remains just south of the waters through the period and
weak pressure gradient keeps winds less than 15 knots and seas
mainly in the 2-4 ft range. Onshore flow today and Saturday will
become more offshore Sunday and Monday. Main impacts will be
offshore moving storms this weekend and into early next week with
periods of heavy rainfall and possible strong storms with gusty
winds and hail.

Rip Currents: In the weaker onshore flow will continue a low-end
Moderate Risk of Rips at local beaches with surf/breakers around 2
feet for most locations.


Light transport winds will lead to low daytime dispersions today
and Saturday.


The wet and unsettled pattern and heavy rainfall potential this
weekend into early next week, mostly across Northeast Florida,
closer to the stalled frontal boundary will lead to river rises
across all areas, but some potential for minor river flooding will
exist along the Santa Fe River Basin in NE FL, along with the
Black Creek System in Clay county if some of the higher end 3 to 6
inch rainfall totals in some ensemble runs pan out.



AMG  54  70  57  72  54 /  40  90  60  50  20
SSI  60  71  61  70  59 /  40  90  60  60  40
JAX  59  73  62  72  59 /  50  80  60  70  60
SGJ  61  76  64  74  61 /  70  70  50  70  70
GNV  60  78  64  76  60 /  60  60  60  80  80
OCF  63  82  66  80  62 /  60  60  50  70  80


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