Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 270300 AAA

Area Forecast Discussion...UPDATED
National Weather Service Miami FL
1100 PM EDT Mon Jun 26 2017

As of 1100 PM EDT...Quick late evening update to bump up PoPs
across the Gulf Coast to account for cluster of thunderstorms that
have developed over coastal Collier County, along with another
area of storms over Lake Okeechobee. These storms have likely
formed in response to convergence along outflow boundaries from
earlier afternoon storms. This activity should continue for the
next few hours, with frequent lightning and locally heavy rainfall
the primary threats, and will continue to monitor potential
flooding concerns in vulnerable areas in and around the Naples
metro. Elsewhere across the region, mainly dry conditions persist,
with a few isolated showers over the Atlantic waters.

For the rest of tonight, the Gulf convection should begin to
slowly wane and dissipate over the next few hours, similar to
activity near Lake Okeechobee. A light land breeze is still
expected to develop off the east coast, helping to focus
additional isolated to scattered showers and storms through the
remainder of the night, mainly over the Atlantic waters. Low
temperatures will generally be in the 70s.


.PREV DISCUSSION... /issued 803 PM EDT Mon Jun 26 2017/

AVIATION... Isolated showers with a couple rumbles of thunder
will continue to dwindle over the interior during the next few
hours, leaving behind scattered low clouds with bases around 3000
ft msl. Wind will decrease to light and variable overnight. Aft
around 27/1300Z, south east winds will again increase to near 10
KT. VCSH conds should begin to develop aft 27/1700Z or 18Z.
Convection will occur closer to the east coast TAF sites on
Tuesday afternoon, but still mainly concentrated in the interior.

PREV DISCUSSION... /issued 715 PM EDT Mon Jun 26 2017/

UPDATE...Convection this afternoon has been a little sparser
than expected despite the numerous boundary collisions. Current
forecast updates are mainly to cut back rain chances into this
evening, with ongoing boundaries keeping at least isolated
convection going through late evening. Latest RAP analysis shows
very light NE steering flow (less than 5kts), but this may be
enough that new activity that gets going along collisions will
trend towards the west side of the interior.

Land convection dies by late evening with mesoscale models
showing the overnight landbreeze leading to the development of
showers and storms over the water late tonight. It remains warm
and muggy, otherwise known as South Florida in late June, with
lows in the 70s.

PREV DISCUSSION... /issued 411 PM EDT Mon Jun 26 2017/


THIS AFTERNOON AND TONIGHT: Frontal boundary is draped across the
north Central peninsula this afternoon, pushing the ridge axis
further south into our region. With the axis overhead steering
flow is very light, with a little more southerly component than
the past few days. Scattered showers and storms are ongoing along
both seabreezes as they move inland this afternoon. Boundary
collisions, along with the collision of the seabreezes will
continue to drive development into the evening hours. Given the
light flow, storm movement will be minimal with heavy rain, gusty
winds, and lightning the main concerns. While most activity will
remain over the interior, outflow boundaries may drive a few
storms into either coast.

Convection dies late tonight with mesoscale models hinting at
landbreeze development leading to the development of showers and
storms over the water and adjacent land areas overnight.

TUESDAY AND WEDNESDAY: Upper level trough moving across the eastern
US erodes the northern side of the western Atlantic ridge through
midweek. Low level front currently across North/Central Florida will
slowly drop south through mid week, but as is usually the case this
time of year, washes out before it reaches Lake Okeechobee.

Prevailing flow will become more southwesterly, though fairly light
at 10kts or less, with a modest increase in mid level moisture and
slightly cooler temperatures aloft. All of the above will lead to a
higher coverage of showers and storms as we head into mid week. We
should see both seabreezes developing and moving inland, with the
best coverage during the late afternoons and evenings over the
interior with the seabreeze collision.

THURSDAY THROUGH UPCOMING WEEKEND: Remnant frontal boundary across
the FL peninsula washes out into late week across the state. Upper
level trough will exit the northeastern US as the upper level
extent of the Western Atlantic ridge rebuilds across Florida. The
surface ridge behind the front across the Mid Atlantic will move
offshore and reinforce the western Atlantic ridge, bringing a
return of prevailing deep easterly flow. This drier, more
subsident pattern will allow rain chances to drop closer to
seasonal norms for this time of year with afternoon convection
favoring interior and Gulf coast areas as the east coast
seabreezes moves inland faster.

MARINE...Frontal boundary across North/Central Florida will weaken
the western Atlantic high, leaving light easterly flow in place
through midweek. Both the Gulf and Atlantic seabreezes will develop
and move inland each afternoon, bringing winds up to around 10kts
near the coast. Best coverage of showers and thunderstorms will
generally be inland, however outflow boundaries could enhance some
convection over the waters. High pressure rebuilds to the north late
week with east-southeast winds returning around 10-15kts into the
upcoming weekend.

West Palm Beach  77  91  75  90 /  20  50  30  50
Fort Lauderdale  79  90  78  91 /  20  40  40  50
Miami            78  91  78  92 /  20  50  40  60
Naples           76  89  76  91 /  40  30  20  50



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