Scientific Forecaster Discussion
fxus62 kmfl 180750
Area forecast discussion
National Weather Service Miami Florida
350 am EDT Fri Oct 18 2019
Today through Saturday...
An unsettled pattern is forecast to close out the work week and kick
off the weekend as a frontal boundary lingers over Florida while the
parent low pressure system over New England and the Canadian
Maritimes eventually moves away. The frontal boundary will begin to
retreat northward as a warm front, allowing South Florida to remain
within the warm sector. As the warm front pushes northward into
central Florida today, potential tropical cyclone sixteen will
traverse the Gulf of Mexico with a forecast path towards Florida's
Panhandle. The impacts from this lopsided system will be felt well
away from its center.
Friday will again be a day where convection is mainly driven by
diurnal heating and the ample moisture available in the warm sector
along and behind the warm front as it pushes northward. The lake
region will see the highest rain and storm chances today. Other
portions of South Florida may also see convection fire along
boundaries which could lead to training cells as the flow could
be perpendicular to the initiating boundaries.
As we enter Friday night, the progress of ptc sixteen will be a
crucial factor in determining what, if any, potential threat for strong
to severe storms will exist for South Florida. The enhanced wind
shear provided by a low level jet on the east side of the system
will create a concern for tornadic activity over portions of the
Gulf Coast and possibly even the Lake Okeechobee region into Metro
Palm Beach/Broward tonight into Saturday.
0-1 srh values exceed 100 m2/s2 overnight in most guidance solutions
which demonstrates the environment capable of supporting strong to
severe storms if convection develops and is able to tap into the
environment. Current Storm Prediction Center day 1 and 2 outlooks
(swody1 & swody2) support the notion that the greatest threat of
severe storms remains to the north, closer to the forecast track of
the center of ptc sixteen. The threat to southern Florida remains
non-zero and heavily reliant on convection being able to access the
high shear environment.
As ptc sixteen eventually moves ashore and the associated cold front
pushes across the peninsula of Florida on Saturday, shower and
thunderstorm chances will continue to rise. The potential for strong
storms continues through Saturday as the wind shear is still present
through a good portion of the day thanks to a 30-40 kt 700 mb jet
that remains over much of the peninsula as the front advances
southward. The additional convection and associated cloud cover
should help keep temperatures a few degrees cooler on Saturday
compared to Friday and some previous days where lower 90s were more
common than upper 80s.
Saturday night through Friday...
As of 2 am EDT, current potential tropical cyclone (ptc) sixteen
is forecast to progress from the central Gulf of Mexico towards
eastern North Carolina over the course of the weekend. A warm
front, initially located in the Lake Okeechobee region, will
gradually lift towards the north by Sunday. As the front departs,
this will allow winds to veer from the southerly direction, and
thus, warming temperatures. Both record high maximum temperatures
and record high minimum temperatures look to be in jeopardy
during this time frame. See climate section for more.
With this front, an increase in low to mid level flow is
anticipated. Furthermore, models are hinting at multiple vorticity
perturbations firing off from ptc sixteen and drifting southward
across portions of South Florida. GFS is a little more potent than
ECMWF, but regardless, thunderstorm development will be higher
this weekend compared to the last several days. This is due to the
multiple rounds of vorticity perturbation traversing the area
along with ample lift from the aforementioned warm front and
additional low-level boundaries (i.E. Outflow boundaries, sea
breeze, etc.). increasing low-level shear will also promote the
risk of isolated funnel clouds, and perhaps a tornado, though
higher probabilities exist in the short term.
With all of the above in mind, there is some concern for strong to
severe thunderstorms to develop Saturday/Saturday evening,
especially for the northern and western portions of the County Warning Area.
Lightning, localized flooding, and damaging winds are all
possible, with a conditional tornado risk as well with any
supercells that may develop. The Storm Prediction Center has
placed a marginal risk for severe thunderstorms just to the north
of the County Warning Area Saturday, however this can certainly change as the
forecast evolves with time. In regards to the Storm Prediction Center risk, this is
just a generalized forecast and severe storms can occur outside of
the targeted areas.
The bottom line for this upcoming weekend is to keep up with the
By Monday of next week, generally seasonal and benign conditions
are expected. This is forecast to continue into Tuesday. Rain
chances should increase by mid to late week as a cold front
approaches the region and stalls to the south of the Florida Keys.
Slightly cooler temperatures should be in store for South Florida once
the front passes, though this just means temperatures fall back to
near normal for this time of year.
potential tropical cyclone sixteen over the Gulf of Mexico is
expected to approach the Florida Panhandle this weekend,
increasing Gulf winds and seas. Cautionary wind conditions are
possible Friday afternoon with a Small Craft Advisory in effect
beginning Friday night for both winds and seas in the Gulf.
Cautionary conditions are possible across the Atlantic waters
tonight. Small craft should exercise caution. A west/SW swell of 1-3
ft should persist from Saturday into Sunday. Showers and
thunderstorms, some strong, will increase in coverage for today
into the weekend across all local waters.
increasing convective activity through the taf period with a focus
this afternoon through Friday night. Overnight fog could be an
issue at fog-prone terminals like apf and tmb. Sub-VFR conditions
are possible with morning fog and any convection that impacts a
terminal. Confidence is too low to introduce any restrictions with
this issuance; short-fused amendments will likely be necessary.
there is an elevated risk for rip currents for the Gulf beaches
this weekend into early next week.
near record high minimum temperatures and high maximum
temperatures are forecast to either break or tie records through
the beginning of next week. Forecast minimum temperatures and
records for the next three days below...
Location date forecast hi-min record
Naples 18 Oct 76 76 in 1968
West Palm Beach 18 Oct 77 79 in 1998
Fort Lauderdale 18 Oct 79 80 in 2018
Miami 18 Oct 78 79 in 1928
Naples 19 Oct 76 78 in 1968
West Palm Beach 19 Oct 77 80 in 2018
Fort Lauderdale 19 Oct 79 79 in 2013
Miami 19 Oct 78 79 in 1970
Naples 20 Oct 76 76 in 2013
West Palm Beach 20 Oct 76 78 in 2017
Fort Lauderdale 20 Oct 78 79 in 1993
Miami 20 Oct 78 80 in 1969
Preliminary point temps/pops...
West Palm Beach 88 77 86 76 / 40 50 60 30
Fort Lauderdale 88 79 87 78 / 30 50 60 30
Miami 89 78 87 78 / 30 50 50 30
Naples 89 76 87 76 / 30 50 70 50