Area Forecast Discussion
Issued by NWS Miami, FL
FXUS62 KMFL 091518
Area Forecast Discussion
National Weather Service Miami FL
1018 AM EST Fri Dec 9 2016
Current radar trends show bands of light showers hastily moving
west to east across the region. The 12Z MFL sounding indicated a
nearly saturated layer from the surface to just above 700 mb,
with drier air residing in the mid levels. Also of note, SB CAPE
values were close to zero, so not expecting much in the way of
convection. Through this afternoon, short term models concentrate
shower activity along the east coast metro and over the Atlantic
waters. Thus, have lowered PoPs along the western peninsula to
slight chance category and raised PoPs slightly further east. As a
cold front continues to move south of our region, north/northeast
winds will strengthen. Have updated the winds grids to better
represent this pattern, otherwise forecast appears on track.
.PREV DISCUSSION... /issued 539 AM EST Fri Dec 9 2016/
Scattered showers are expected to develop by mid-morning then
persist through much of the day. For eastern terminals, periods of
showers will likely continue into Saturday, so VCSH has be placed
for duration of TAF period. VFR conditions should prevail, but brief
CIG/VSBY restrictions are possible in/near SHRA. Winds NNW at 10 KT
early this morning will veer NNE and increase to 15 KT with gusts to
near 25 KT through this evening, then perhaps diminish just slightly
PREV DISCUSSION... /issued 325 AM EST Fri Dec 9 2016/
NEAR TERM /THROUGH 6 PM FRIDAY EVENING/...
As of 325 AM EST...A cold frontal boundary continues to slowly
move southward across the region, with the latest surface
observations indicating the front located along central Miami-Dade
and mainland Monroe counties. Ahead of the front, in areas such
as Homestead, a muggy airmass continues to remain in place with
dewpoints around 70. Behind the front, drier air has begun to work
into the region from the north with dewpoints falling into the
60s and even upper 50s in portions of Glades and Hendry counties.
While most mainland areas have seen generally dry weather overnight,
the local Atlantic waters and portions of the east coast metro in
Broward and Miami-Dade counties have remained quite active with
plenty of shower activity, aided by a warm Gulf Stream. This trend
looks to continue through daybreak based on the latest high-res
models, and cannot rule out a waterspout or two with this activity
especially off Miami-Dade county where the low-level flow will
initially remain weak this morning.
For the rest of today, scattered showers look to occur especially
across eastern areas, as the flow shifts to north/northeast in the
wake of the front. The flow will become breezy by the mid morning
hours as well especially along the east coast. While cannot out a
rogue shower across western areas today, expecting generally fair
and dry weather with a surge of dry air from the north.
Temperatures will be about 5-10 degrees below normal today, with
highs only in the lower to mid 70s for most areas, with portions of
Hendry and Glades counties struggling to make it out of the upper
60s. With mostly cloudy skies and breezy conditions expected, it
will definitely feel cooler than recent days.
SHORT TERM /6 PM FRIDAY EVENING THROUGH SUNDAY NIGHT/...
Breezy northeast to east flow will prevail through the short term
period, with gloomy weather for December. Behind the frontal
passage, slightly drier air will build into the region from the
north, although low-level moisture looks to hang tough across
south and eastern areas as the frontal boundary slowly drifts and
washes out north of Cuba.
Much of the period will feature mostly cloudy to occasionally cloudy
skies with scattered showers possible especially across eastern
areas as they stream in off the Atlantic. The best chance for some
sun and dry weather will be across western areas, where the driest
air looks to filter in.
Temperatures will initially be below normal for the first half of
the weekend with highs Saturday ranging from the mid to upper 70s
and lows Saturday night ranging from the upper 50s to upper 60s.
Temperatures will moderate back to normal for the latter half of the
weekend with highs Sunday ranging from the upper 70s to near 80 and
lows Sunday night ranging from the 60s to near 70.
LONG TERM /MONDAY THROUGH THURSDAY/...
Long range guidance continues to be in fairly good agreement with
more tranquil weather returning to the region for much of the work
week as weak high pressure builds across the region from the north.
This high pressure will help decrease winds across the region and
shift the flow to east/southeast. Widely scattered showers will
still remain possible across the region, especially across portions
of the east coast metro. Temperatures will be near to slightly above
normal for mid-December.
Hazardous marine and small craft advisory conditions likely through
the weekend across the local Gulf and Atlantic waters...
A cold front will continue to move south of the region into the
Florida Straits today, with increasing northeasterly flow in its
wake. These winds will lead to hazardous boating conditions today
and continuing through much of the weekend, with wind speeds around
20 knots, increasing to as high as 25-30 knots this weekend
especially over the Atlantic waters. Seas will build to 6-9 feet
in the Atlantic, highest in the Gulf Stream, and 4-7 feet in the
Gulf waters highest offshore. Small Craft Advisories are in effect
through much of the weekend. Winds and seas will begin to
decrease beginning Monday as weak high pressure builds across the
Rip current risk will increase to Moderate today for the Atlantic
beaches with increasing north/northeasterly flow. As the flow shifts
more to the northeast and continues to increase Saturday, rip
current risk will likely be High for the Atlantic beaches, with
dangerous rip currents likely continuing into early next week.
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 75 68 75 70 / 40 50 30 30
Fort Lauderdale 76 67 75 70 / 50 50 30 40
Miami 75 66 76 70 / 50 40 30 40
Naples 71 59 78 63 / 20 10 10 10
AM...Small Craft Advisory until 4 PM EST Saturday for AMZ630-650-651-
GM...Small Craft Advisory until 4 PM EST Saturday for GMZ656-657-676.