Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 280705

Area Forecast Discussion
National Weather Service Miami FL
305 AM EDT Wed Jun 28 2017



As of 305 AM EDT...A weak frontal boundary continues to slowly
wash out with time just north of the region, as an upper-level
trough exiting out of the Northeast keeps the Bermuda high
influence limited across South Florida. This synoptic setup will
lead to another day of sea breeze driven circulations with
otherwise light flow.

Through daybreak, isolated to widely scattered showers will be
possible in a moist environment, as PWATs linger around 2 inches
slightly above normal for this time of year. Any activity over
inland areas should be rather brief and light, with the better
chance for more robust showers and a few storms over the local
Atlantic and Gulf waters.

After daybreak, a similar forecast to yesterday will take shape,
with both Atlantic and Gulf sea breezes developing in the late
morning and into the afternoon hours, being the primary focus for
scattered shower and thunderstorm development later today. The best
chances for thunderstorms will be across the interior, although
activity will also be possible along the coasts as well, especially
initially along the leading edge of the sea breezes and later in the
afternoon on the heels of outflow boundaries that refire additional
convection. Midlevel temps near normal for this time of year and an
overall lack of forcing beyond typical mesoscale circulations will
yield general thunderstorms with lightning and heavy rain the
primary threats. With plenty of instability in place and PWATs near
2 inches, cannot rule out some brief gusty winds with a weak wet
microburst with the strongest storms.

Convection will begin to slowly wane towards sunset, gradually
shifting towards marine areas, with a few lingering showers and
rumbles of thunder possible over the mainland. High temperatures
today look to reach into the lower 90s for most, with mid 90s across
portions of the interior. With plenty of tropical moisture in place,
it will feel hot with heat indices likely reaching into the lower
100s across many areas as well, especially south.


The short term period will continue to see the frontal boundary to
the north gradually wash out and retreat northward with time, as
upper-level energy across the Northeast helps keep the Bermuda high
suppressed and a weak flow pattern dominated by sea breezes in place
across South Florida. Other than some minor surges in moisture
through the period, the pattern will generally remain stagnant
across the immediate region, with scattered to locally numerous
showers and thunderstorms primarily focused in interior areas during
the afternoon and evening hours. Midlevel temps remain near normal,
so most thunderstorm activity will be garden variety, although a few
strong storms each afternoon will be possible. By Thursday, the
Bermuda high will begin to restrengthen and mark a transition to a
more moderate easterly flow regime.

Temperatures will be near to slightly above normal with highs in the
upper 80s/lower 90 along the coasts to lower and mid 90s in the
interior. Low temperatures will generally be in the 70s, with a few
readings near 80 in the east coast metro.


The long term period will continue to see the reestablishment of the
Bermuda high, along with a predominately summertime easterly flow
regime. This pattern will feature typical sea breeze development
during the afternoon hours, with scattered showers and thunderstorms
favored over the interior and Gulf Coast, with nighttime activity
favored over the Atlantic waters and east coast. With the Bermuda
high becoming well established, subsidence in the mid-levels will
lead to near of slightly below normal PWATs for this time of year,
helping to keep rain chances towards seasonal norms. Temperatures
will be near to slightly above normal during the long term period.


Generally good boating conditions will prevail across the local
waters for the next several days with light southeasterly flow.
Local sea breezes may briefly enhance winds near the coast to 10-15
knots during the afternoon, from the southeast along the Atlantic
coast and west/southwest along the Gulf coast. Additionally, locally
erratic winds along with lightning will be possible in and around
thunderstorms which are expected to be isolated to widely scattered
in coverage. Waves will be 3 feet or less heading into the weekend.


Although isolated showers cant be ruled out through late morning,
expected coverage and confidence in timing are not high enough to
warrant inclusion in 6z TAF issuance. By midday, Atlantic and Gulf
sea breezes will begin to penetrate inland, and scattered showers
and thunderstorms should develop in association with these
boundaries. Thus, VCTS in place through 0z, and brief restrictions
are quite possible in/near any convection. Activity should
diminish in intensity by late evening, but guidance suggests
gradually moistening atmosphere, so have placed VCSH for eastern
terminals through the end of the period.


West Palm Beach  91  78  91  78 /  50  30  50  40
Fort Lauderdale  90  79  91  80 /  50  30  40  30
Miami            92  79  91  79 /  50  30  40  30
Naples           91  76  91  76 /  40  20  50  40



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