Scientific Forecaster Discussion
fxus62 kmfl 201655
Area forecast discussion
National Weather Service Miami Florida
1255 PM EDT Mon Aug 20 2018
VFR conditions should prevail with ongoing afternoon showers and
thunderstorms generally confined to inland of terminals today.
Expect activity to be closest to pbi, fxe, tmb, and apf, where thunderstorms in the vicinity
in place, otherwise vcsh. Convection looks to be less widespread
Tuesday so have maintained dry forecast after 23z today. Southeast wind (w
at naples) around 10 knots today, calm tonight, then becoming southeast again
by late Tuesday morning.
Previous discussion... /issued 936 am EDT Mon Aug 20 2018/
little in the way of changes to the forecast this morning, as the
expectation remains for showers to develop late this morning along
the East Coast urban corridor then spread northwestward toward the
interior this afternoon, where coverage and intensity will
increase significantly. Environment doesn't appear too favorable
for strong convection and heaviest rainfall should fall over non-
flood prone areas, so main hazard today will be frequent cloud
to ground lightning.
Previous discussion... /issued 338 am EDT Mon Aug 20 2018/
Summer continues as Atlantic surface high pressure remains in
possession of south Florida's synoptic pattern. Warm temperatures
are expected again today (and through the next week) along with
sea breeze development that will allow showers and thunderstorms
to form as well. A slightly drier atmosphere compared to previous
days and less mid level support for convection will point towards
boundary collisions between the sea breezes, convective outflow,
and remnant boundaries as the main focal points for convective
activity today. The hail threat appears to be minimal but one
cannot rule out the threat of strong wind gusts and the ponding of
water on roads from heavy rainfall today.
As we start ascending through the atmosphere, the mid and upper
levels show high pressure stretched across the Gulf of Mexico
while a mid-level trough related to a low pressure system over
the eastern two-thirds of the United States continues its eastward
progression into the Great Lakes and Canada through mid-week. A
moisture boundary associated with the trough amplifying into the
southeastern United States will focus moisture over the peninsula
of Florida which should allow for fairly healthy rain chances late
week into the weekend. As the mid to upper level system moves on,
high pressure will attempt to build back at the mid-levels over
the mid-south United States. The distance between this mid-level
high and South Florida combined with the amount of available
moisture in the region could lead to a more unsettled pattern
capable of producing convection not only with the diurnal heating
cycle but also overnight.
As the extended period draws to a close, another mid-level trough
will push east across the nation with an amplification southward
along the way. It's still way too far out in the forecast period
to discern more than general trends with this trough but it does
remind US that soon the transition of seasons will begin to our
north which could lead to mid-latitude features pushing further
south that allow tropical moisture to focus over the region. At
this point however, the forecast has no such features or any
tropical concerns for the next 7 days for South Florida.
high pressure will remain through the week with showers and
thunderstorms capable of producing strong wind gusts, locally
higher seas, heavy rain, and lightning. Otherwise, no headlines
are anticipated for winds or seas through the week.
Preliminary point temps/pops...
West Palm Beach 77 89 76 90 / 20 20 10 40
Fort Lauderdale 80 89 79 89 / 20 20 20 40
Miami 79 89 78 90 / 20 20 20 40
Naples 77 90 77 90 / 20 30 20 40