Area forecast discussion
National Weather Service Miami Florida
245 PM EDT Tuesday may 21 2013
..Flood Watch in effect until 10 PM EDT this evening for East
Coast metropolitan areas...
Short term...
the east and West Coast sea breezes were developing along both
coasts of South Florida early this afternoon. These sea breezes
will push slowly inland through the rest of the afternoon hours
helping to generate showers and thunderstorms over the area. The
storms will be slow moving this afternoon into this evening...as
the steering flow will be light from the south ahead of a trough
of low pressure located over the eastern Gulf of Mexico.
The GPS-met satellite images where showing the precipitable water values to be
between 1.6 to 1.7 inches early this afternoon over South
Florida. The average precipitable water value for this time of year is around
1.35 inches for South Florida. This will allow for heavy rainfall
over South Florida this afternoon into this evening. So, will
continue to mention heavy rainfall in the forecast for South
Florida for this afternoon into this evening.
The heavy rainfall from the storms this afternoon into this
evening over the East Coast metropolitan areas will allow for some
flooding to occur...as the grounds are very saturated from the
heavy rainfall from the storms yesterday. Therefore...the Flood
Watch will remain in place over the East Coast metropolitan areas through
late this evening.
The middle to upper level trough over the eastern Gulf of Mexico will
move east tonight through the Florida Peninsula as the upper level
low over northern Florida moves east into the western Atlantic
waters. This will allow for the deeper moisture over South Florida
to move east into the western Atlantic waters on Wednesday which
will allow for some drier air to work into the area from the
central Gulf of Mexico. The drier air will stick around on
Thursday over South Florida. However...there will still be enough
moisture over South Florida each day to allow for scattered
showers and thunderstorms to develop over the area on Wednesday
and Thursday along the sea breezes with the best coverage over the
interior areas.
Long term...
a cold front located over the central United States is forecast by
the long range models to move southeast and through South Florida
early this weekend. High pressure should then build into the area
from the north late this weekend into early next week. This will
allow for much drier air to work into the area from the north for
late this weekend into early next week. So will keep a slight
chance of probability of precipitation over South Florida for the early part of this
weekend before going dry for the second half of this weekend into
early next week.
&&
Aviation...
scattered showers and thunderstorms will continue to develop and
push slowly north through the afternoon hours. So kept thunderstorms in the vicinity for all
taf sites through the afternoon. A few showers may move near the
East Coast taf sites overnight. An upper level trough will shift
east tonight into Wednesday...pushing the best dynamics over the
Atlantic waters. So thunderstorm activity is expected to start near
the end of the taf period along the sea breeze boundaries.
&&
Marine...
the winds will be southerly below 10 knots through late this
week...before increasing to breezy conditions from the northeast
direction for this weekend. This will allow for the seas to remain
below 6 feet for both the Atlantic and Gulf waters of South
Florida through late this week into early this weekend...before
increasing to around 6 feet in the Gulf Stream waters of the
Atlantic by late this weekend.
&&
Fire weather...
the relative humidity will remain above the 35 percent critical
value over South Florida through rest of this week. So no problems
are expected with the fire weather over South Florida.
&&
Preliminary point temps/pops...
West Palm Beach 72 86 74 88 / 50 50 40 30
Fort Lauderdale 73 86 77 88 / 50 50 30 30
Miami 73 87 76 89 / 40 50 30 30
Naples 70 87 71 88 / 30 40 20 20
&&
Mfl watches/warnings/advisories...
Florida...Flood Watch until 10 PM EDT this evening for coastal Broward-
coastal Miami Dade-coastal Palm Beach-metropolitan Broward-metropolitan
Miami Dade-metropolitan Palm Beach.
Am...none.
GM...none.
&&
$$
Discussion/marine/fire...54/bnb
aviation/radar...84/AK
