Scientific Forecaster Discussion
fxus62 kmfl 262350 aaa
Area forecast discussion...updated
National Weather Service Miami Florida
750 PM EDT Wed Jul 26 2017
the winds will become light and variable this evening into the
overnight hours tonight at all of the taf sites. The winds will
then increase to around 10 knots from the easterly direction on
Thursday at most of South Florida taf sites, except for kapf taf
site where the winds will become westerly after 18z. The weather
will also remain dry tonight into Thursday for most of the taf
sites. The only exception is for kapf taf site where there could
be some showers after 18z. Therefore, vcsh will be introduce for
kapf taf site for Thursday afternoon. The ceiling and vis will
also remain in the VFR conditions for all of South Florida taf
Update...convective pattern this afternoon went pretty much as
expected with scattered storms over the interior and Gulf Coast,
with a few stronger ones along boundary collisions. Coverage is on
the wane with sunset, though a few boundaries remain that may kick
off isolated activity for the next few hours. Stray Atlantic
shower that may brush the East Coast will be possible overnight,
but otherwise expect dry, warm, and muggy conditions after
evening storms diminish. No significant changes to the ongoing
Previous discussion... /issued 414 PM EDT Wed Jul 26 2017/
This afternoon and tonight: another day of seabreeze driven
convection this afternoon, with coverage so far remaining widely
scattered at best. Southeasterly wind component has pushed the
East Coast seabreeze further inland with convection beginning to
pile up over the interior and towards the Gulf Coast. Expect a
fairly typical evolution for the remainder of the afternoon and
evening with an increase in coverage over the western interior
through the remainder of the daylight hours as boundaries and the
Dewpoints have been a few degrees below forecast today, which in
addition to a little earlier start to convection has held heat
indices generally in the 100-105f range. As we've now just passed
peak heating, don't expect any additional increase in the
temperatures. Therefore, have cancelled the heat advisory for this
afternoon. However, it will remain a warm and muggy afternoon for
those areas that don't see any rain.
Convection diminishes after sunset, with another mostly dry night
outside of the occasional Atlantic shower.
Thursday and friday: upper level troughiness that has been lingering
across S Georgia/North Florida will slide a little further south and east for the
end of the week, eroding the strong ridge that is currently in
place. The low level ridge axis will also migrate south, with
steering flow becoming more south to southwest by Friday.
Current Saharan airmass tracking through the Greater Antilles
doesn't look quite as robust as the previous event, and models
continue to move the bulk of it just to our south. While we will
be on the northern fridge of this airmass, it does look to help
reinforce the dry mid levels already in place.
Expect the seabreezes to overcome any nominal convective inhibition
due to the drier air, bringing scattered showers and storms both
afternoons. Coverage will favor the western interior on Thursday and
towards the western side of the East Coast Metro on Friday as
steering flow shifts.
With lower mid level heights, high temperatures will be down a
degree or two from Wednesday, though still above normal in the low
90s along the immediate coasts, and mid 90s for the Metro areas and
interior South Florida. This difference may be enough to hold heat
indices below heat advisory criteria, but still climbing into the
100-105f range both days.
This weekend into early next week: not much change in the models as
we head into the extended, with models showing a robust upper level
shortwave/low moving across the Great Lakes into the mid Atlantic
and deepening a trough along the East Coast. This general trough is
expected to remain in place into next week, potentially digging as
far south as Florida, but at the very least suppressing the western
Atlantic high to our south and east. This trough is expected to
drive an unseasonably robust surface front into the state by early
next week, potentially reaching as far south as Lake Okeechobee.
Deep moisture will be slower to recover, but will generally be on
the upswing as south-southwesterly flow increases. The result of all
these features will be shower/storm chances becoming likely each
afternoon across the entire region, with potentially a few more
stronger storms as temps aloft cool.
Marine...weakening ridge will keep winds southeasterly around 10
knots through the end of the week, before veering more south-
southwesterly into the weekend as a front sags into North Florida.
Expect both the Gulf and Atlantic seabreezes to develop the next
few afternoons, with the Atlantic breeze struggling to develop by
late week with the stronger southwest breeze.
Afternoon showers and storms will generally remain over the
interior, with more isolated activity over the open waters during
the nights and morning. Coverage of showers and storms expected to
increase as we head into the weekend.
Preliminary point temps/pops...
West Palm Beach 80 93 79 95 / 10 10 10 40
Fort Lauderdale 82 92 81 93 / 10 10 20 50
Miami 81 93 80 93 / 10 20 20 50
Naples 78 93 77 93 / 20 30 30 20