Scientific Forecaster Discussion
fxus62 kmfl 171130
Area forecast discussion
National Weather Service Miami Florida
730 am EDT Tue Sep 17 2019
VFR conditions expected through the period. Terminals should
remain fairly dry today with a few showers possible along the
East Coast, but coverage will be widespread enough to handle with
amendments. Prevailing flow will become breezy this afternoon
between 14-18z as the winds become northeasterly, with the
exception of a north/northwest sea breeze developing over kapf.
Previous discussion... /issued 343 am EDT Tue Sep 17 2019/
Today and tonight...
North-northwest flow will prevail aloft as South Florida is located between
upper ridging over the southern Gulf of Mexico and residual
troughing in the wake of Hurricane Humberto over the western
Atlantic. Mid-level subsidence wrapping around the back side of the
tropical system will push south into our area this morning and will
remain in place through the short-term period. This will serve as a
limiting factor for shower and thunderstorm development today,
although can't rule out a low end chance over eastern portions of
our area as northeast low-level winds associated with the Atlantic
sea breeze allow for some localized convergence leading to possible
development around the East Coast Metro areas during the afternoon
and evening. With the easterly wind component, the East Coast
Metro areas will be a bit cooler than on Monday, but all portions
of our area (away from the immediate coasts) should once again
top out in the 90s. The somewhat drier air should allow interior
lows to dip into the lower to mid 70s, with readings closer to 80
along the Atlantic coast.
Wednesday and Thursday...
The pressure gradient will strengthen in response to the departing
Humberto along with high pressure building down the Lee side of the
Appalachians into northern Florida. This will result in a breezy
period for South Florida with gusty conditions likely at times along
the Atlantic coastal interface. Drier air will persist in the mid
levels with shower and thunderstorm coverage remaining limited.
Given the prevailing northeast flow the best afternoon/evening
chances will be along the Gulf Coast region. Temperatures should
remain seasonal, with the warmest readings over interior southwest
Friday through Monday...
Look for an easterly low-level wind pattern to become established as
low-level ridging expands to our north and a low pressure trough
advances into our area from the east. This will bring an increase
in deep layer moisture across South Florida into the weekend with
greater shower and thunderstorm coverage anticipated. Given the
flow regime, interior and West Coast locations will be most favored
for afternoon/evening thunderstorm development. Temperatures should
A northeast swell from Hurricane Humberto will gradually increase
through the week. This combined with increasing northeast to east
winds will result in hazardous winds and seas for small craft,
particularly in the Gulf Stream. A Small Craft Advisory remains in
effect through Friday for the Atlantic waters. High surf is a
potential concern along the Palm Beach County coast as well, and a
high surf advisory may be needed for this area by mid to late
An elevated rip current risk will exist for the Atlantic beaches
through the remainder of this week given increasing onshore winds
and building swell. Swimmers and others in the water should exercise
caution, swim near a lifeguard, and follow the directions of public
Preliminary point temps/pops...
West Palm Beach 90 78 89 76 / 20 20 20 20
Fort Lauderdale 90 80 89 77 / 20 30 30 20
Miami 91 79 90 76 / 20 20 20 20
Naples 90 77 92 73 / 0 0 50 20
Florida...high rip current risk through Friday evening for flz168-172-173.
Am...Small Craft Advisory until 8 PM EDT Saturday for amz650-651-670-