Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Miami Florida
241 am EDT Tuesday Aug 4 2015
upper trough over the eastern Continental U.S. Will lift northeast
today...and the subtropical ridge over the western Atlantic will
push into the Florida Peninsula. Surface low pressure over coastal
Georgia/South Carolina will move quickly northeastward today...and
the surface ridge axis will slide northward into central Florida.
This will allow deep east to southeast flow to return to the
Hires and global models show that showers and possibly a few
storms may develop this morning along the East Coast and move
inland. The East Coast sea breeze will develop by middle/late
morning...with convection then developing across the interior and
mainly inland of the metropolitan areas in the early/middle afternoon. Lapse
rates will steepen slightly this afternoon as drier air in the
700-500mb layer moves into the region...with the freezing level
forecast to rise above 15.5kft. So cannot rule a few strong wind
gusts...mainly across The Everglades.
A large area of Saharan dust currently across Puerto Rico and
Hispaniola and northward into the western Atlantic will push into
the central Bahamas by Wednesday morning. A weak area of vorticity
from an old upper low will push northeast...bringing cooler
temperatures aloft (around -7.5c at 500mb). The flow aloft will
veer to the south as well...and a brief moisture surge is forecast
ahead of the Saharan dust with precipitable waters increasing to 2-2.25 inches.
This will lead to good rain chances across the region. The
steering flow will also relax throughout the day...and locally
heavy downpours are possible.
Dry air and Saharan dust push into the region quickly on
Thursday...with precipitable waters falling from 2 inches in the morning to
less than 1.5 inches by the afternoon along the southeast coast.
So mainly dry conditions will prevail for the southeast coastal
areas...with the best rain chances across the lake region Thursday
afternoon. Strong storms with gusty winds are possible.
Friday and Saturday...the upper ridge will weaken once again with
a shortwave trough riding southeast into the Middle Atlantic
States...and then pushing off the eastern Seaboard. This will
provide northerly flow aloft across South Florida. The surface
ridge axis near Lake Okeechobee on Friday will remain almost
stationary. Another low level trough will push into North Florida
over the weekend before stalling. The 850mb ridge will bisect the
region through the period. Dry air and Saharan dust will engulf
South Florida...and only meager rain chances are expected.
Sunday and Monday...slight moistening is forecast to take place
each day...but significant dry air will remain in the middle
levels. A shear axis may push into the lake region in Sunday
afternoon and then remain across South Florida through early next
week. Deep easterly flow will resume...with the best chances of
rain across the interior west and towards the Gulf Coast.
Highs are forecast to be in the low 90s everyday...with lows in
the 70s to around 80 degrees. Heat indices are forecast to be
100-105f each afternoon.
with surface low pressure departing north FL, southeast to east flow will be
more uniform across South Florida than yesterday. This should
keep the most numerous thunderstorms over the interior. Thunderstorms in the vicinity was
used at tmb in case any outflows stir up any convection there, but
went with vcsh elsewhere morning through early afternoon. Apf Gulf
Breeze expected around 18z.
southeasterly to easterly surface winds averaging around 10 knots
should prevail across the Atlantic waters today with seas around
2 feet or less. Lighter and mainly variable winds are expected
across the Gulf waters. Chances for showers and thunderstorms are
possible each day and night along the Atlantic waters through
the middle of the week. Much drier air may keep activity isolated
over the Atlantic waters Thursday and Friday.
Preliminary point temps/pops...
West Palm Beach 91 77 91 77 / 30 10 50 20
Fort Lauderdale 91 79 91 80 / 30 10 50 20
Miami 92 78 92 80 / 30 10 50 20
Naples 91 76 91 78 / 30 10 30 10