Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 221126

Area Forecast Discussion
National Weather Service Miami FL
726 AM EDT Sat Jul 22 2017

.AVIATION...Ongoing SHRA vcnty KAPF expected to continue through
16Z when WSW Gulf breeze develops and pushes inland, then VCTS
though most convection will likely be just inland of site at that
time. For east coast, light/vrb winds become SE with seabreeze
15Z-16Z. VCTS for all ATLC sites with seabreeze push, with
stronger SE flow likely to shift most activity inland of sites by
mid afternoon except for KPBI where SW flow remains a little
stronger. Potential for TS may linger at KPBI through 00Z.


.PREV DISCUSSION... /issued 409 AM EDT Sat Jul 22 2017/

As of 4 AM EDT, stable conditions in the wake of yesterday`s
active weather continue across South Florida during the pre-dawn
hours, as evidenced by last night`s sounding data which clearly
shows a dry low level profile.

Today: the main synoptic features will be the mid-level low along
the northern Gulf coast/trough extending east across northern
Florida, as well as the subtropical ridge nosing in from the Bahamas
across South Florida. The ridge is very slowly expanding north and
this will result in low-mid level flow becoming more southerly.
The leading edge of a narrow Saharan Air Layer (SAL) currently
across the Florida Keys and the far southern Florida peninsula
will also nudge northward with the ridge. Drier air in the 850-500
mb layer should act to limit somewhat the coverage of showers and
thunderstorms, especially metro Miami/Ft. Lauderdale where the
added factor of a stronger Atlantic sea breeze should focus
convection towards the interior. Therefore, highest PoPs will be
over the interior to Lake Okeechobee. Residual cool air aloft
should support a few strong storms with gusty winds the primary
threat, although probably not as active or widespread as
yesterday. After storms dissipate early this evening, expect a
mainly dry night with the exception of scattered showers/isolated
thunderstorms potentially moving onshore along the Atlantic coast
in the low level SE flow.

Sunday and Monday: the subtropical ridge and SAL continue to inch
northward across South Florida, leading to a similar precipitation
pattern as today`s with interior and Gulf coast areas seeing higher
coverage of afternoon storms and east coast areas favored earlier
in the day and again at night. Although the drier air with the
SAL looks to be more predominant on Monday, the northern end of a
tropical wave currently near Hispaniola may brush the area. Also,
the ECMWF model is not as strong with the subtropical high over
South Florida, so kept PoPs a little higher than what the GFS
model is suggesting and closer to persistence/continuity. A few
strong storms still possible on Sunday, then less likely on

Temperatures will be on an increasing trend with the high pressure
aloft and less overall cloud cover, with maxima in the lower to
mid 90s over most areas and lows from the mid 70s interior to
lower 80s urban heat island/coastal metro SE Florida.

Extended period (Tuesday into next weekend): subtropical ridge
looks to remain across South Florida, keeping a SE-S wind flow
with little variation in near-normal moisture levels with
precipitable water values generally between 1.7 and 2.0 inches.
Expect a typical July diurnal pattern of afternoon interior/Gulf
coast storms and night/morning showers/storms east coast. Longer-
range models suggest some drier air could filter into area Friday,
but too early to make significant changes to forecast with near
climatological PoPs the best option for now. Temperatures remain
nearly the same as this weekend.

MARINE...Southeast to south winds generally less than 15 knots
through the middle of next week with seas less than 3 feet.
Coverage of showers and thunderstorms over the local waters will
trend lower than the past few days, except over Lake Okeechobee
where afternoon and evening thunderstorms are expected each day.

BEACH FORECAST...A slight increase in southeast winds means that
the rip current risk at the Atlantic beaches will be slightly
higher than the past few days, although it will still be
categorized as slight. &&

West Palm Beach  91  77  92  79 /  40  20  30  20
Fort Lauderdale  91  79  92  81 /  40  30  30  30
Miami            93  79  92  80 /  40  30  30  30
Naples           91  77  90  77 /  30  10  30  20




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