825
FXUS62 KMFL 081947
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
247 PM EST Wed Jan 8 2025

...New LONG TERM...

.SHORT TERM...
(Rest of today through Thursday)
Issued at 1246 PM EST Wed Jan 8 2025

The forecast for this afternoon remains dry and cool as a broad area
of surface high pressure builds across the central/southeastern
United States. This will continue to promote northerly to
northwesterly surface flow across South Florida, thus supporting
continued cooling and low dew point temperatures this afternoon. In
fact, temperatures will struggle to rise above 70 along the coast
and beyond the mid 60s over the interior this afternoon.

Tonight, the low-level northerly to northwesterly flow becomes
stronger over the western Atlantic with the building ridge aloft.
This will allow lower dewpoints to spread back across all of south
Florida, even near the coast. Since we`re unlikely to completely
decouple and primarily have our temperatures dominated by cold air
advection and diurnal processes, will lean again towards the raw
global guidance for morning lows on Thursday. This would result in
lows right around 40 degrees in the Moore Haven, Clewiston,
Immokalee region (a few upper 30 degree readings not out of the
question). Along the East Coast, low to mid 40s will be more common
across Palm Beach county, with upper 40s to low 50s more common from
Broward south where the Lake tends to block some of the CAA from the
northwest. Factoring in the wind, locations will probably feel about
3-5 degrees colder than the above advertised temps.

Climatologically speaking, it`s the high temperatures on Thursday
that would be more significant than the morning lows. As the eastern
branch of the northern stream pivots offshore, cooler lower
tropospheric temperatures along its base will scrape south Florida.
This means that the temperatures we`ll pull down from aloft are
nearing the cool tail of both the model and reanalysis climate
datasets. We have high confidence in this temperature forecast due
to the narrow spread between the global ensembles and even the NBM
suite. Expect highs to barely crack 60 across Glades and Hendry
counties, remain in the low 60s across the interior of south
Florida, and hold in the middle to upper 60s along the east coast.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 144 PM EST Wed Jan 8 2025

This part of the forecast periods starts off with the last cold
night of the current episode Thursday night and early Friday as
the surface high pressure over the eastern U.S. noses down into
Florida. As the night progresses, winds just above the surface
should turn out of the NE which will effectively cut off the cold
air advection, so the main uncertainty in the minimum temperatures
lies in how much surface decoupling will counteract the warm air
advection aloft. Spread in the model guidance remains considerable
as we would expect in this scenario, so the best course of action
at this time is to use the NBM mean and adjust down a degree or
two closer to the raw model guidance (similar to the approach used
for the short term temps). This yields low temperatures near 40
west and south of Lake Okeechobee, with 40s for most of the
remainder of the area, then a rather sharp gradient within a few
miles of the Atlantic coast where the warm air advection will be
most pronounced and keep lows in the 50s there. The low
temperatures will likely occur earlier in the night, then level
off or perhaps increase slightly during the last couple of hours
before sunrise Friday.

The warming trend will be well underway on Friday as a mid-level
shortwave ridge moves overhead and surface winds veer ahead of the
next frontal system over the Gulf of Mexico. Highs will rebound
into the 70s area-wide, close to the normal for this time of year.
Friday night will be the warmest night of the stretch, with lows
in the 50s and 60s.

Saturday will be a transition day as the cold front moves down the
Florida peninsula. The mid-level longwave trough will become
increasingly positively-tilted and sheared as it moves east
across the Gulf coast states, which will act to weaken the large-
scale forcing necessary for significant precip/convection. The
more likely scenario at this time is for a broken band of showers
moving S/E across the Lake Okeechobee and Gulf coast areas during
the midday or afternoon hours, then fall apart as it progresses
towards SE Florida. Highest PoPs in the 30-40% are confined to SW
Florida, with PoPs lowering to 20% into Broward and Palm Beach
counties, and less than 20% across Miami-Dade County. Precip
amounts are expected to remain a tenth of an inch or less, with
model-based high-end amounts of around a third of an inch. With
lack of upper level support/forcing, we will continue to not
include thunder. Ahead of the front, temperatures should approach,
if not reach, 80 degrees, especially over metro SE Florida, with
70s elsewhere.

Confidence is decreasing in the forecast for the latter half of
the long-term period. Models generally agree in a frontal passage
late Saturday or Saturday night, but due to the zonal mid/upper
level flow left behind there is some disparity in the guidance in
how far south the front makes it, as well as the strength of the
cold air advection and amount of clouds behind the front. For
now, the front looks to be south of the peninsula on Sunday, but
the 12z ECMWF suggests the front could move back to the north
across our region Sunday night and Monday ahead of a developing
frontal wave over the Gulf of Mexico, then move back south of the
area Monday night and Tuesday. The 12z GFS ensemble mean suggests
a decent number of members also showing this scenario. Therefore,
quite a bit uncertainty exists at the end of the forecast period
with regards to temperatures and precipitation chances. For now we
will continue with a mostly dry period with the model blends
showing lows in the upper 40s and 50s Sunday through Tuesday, and
highs in the upper 60s to mid 70s. Model temperature spreads are
on the order of up to 10 degrees between the first and third
quartiles during the Sunday-Tuesday period, a clear indication of
the low confidence in this forecast. No doubt there will likely
be changes in upcoming forecasts to temperature and precipitation
for early next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1246 PM EST Wed Jan 8 2025

VFR conditions expected across all sites through the period. Northerly
to northwesterly flow at 5-10 kts persists today, becoming light
and potentially variable overnight, and increasing once again out
of the north-northeast tomorrow morning.

&&

.MARINE...
Issued at 1246 PM EST Wed Jan 8 2025

Winds and seas at advisory levels will remain below subside
today, only to approach or reach advisory thresholds again on
Thursday as the eastern edge of a high pressure shifts into the
western Atlantic. A subsequent lull is anticipated as the calmer
center of the ridge settles over the Atlantic. However, winds and
seas could return to advisory levels by Saturday as a Gulf low
moves from the Gulf of Mexico across the Southeast and exits off
the Mid-Atlantic coast.

&&

.BEACHES...
Issued at 1246 PM EST Wed Jan 8 2025

The high rip current risk will continue along the Palm Beaches as
surf is slow to subside today. The high risk will likely then
spread down the east coast on Thursday and could then spread to
the Gulf by the weekend. Beach conditions will slowly improve late
this weekend into early next week.

&&

.FIRE WEATHER...
Issued at 232 AM EST Wed Jan 8 2025

Relative humidity levels are forecast to remain above critical
levels today. On Thursday however, RH`s are forecast to fall
between 25-30% and some locations even into the low 20% range.
While Red Flag conditions are not expected at this time, there is
a low (10-20%) chance that 20 ft winds could reach criteria at the
same time. Conditions will moisten back to above critical levels
Friday through the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            49  67  50  73 /   0   0   0   0
West Kendall     45  67  46  74 /   0   0   0   0
Opa-Locka        48  67  49  74 /   0   0   0   0
Homestead        47  67  49  74 /   0   0   0   0
Fort Lauderdale  48  66  50  72 /   0   0   0   0
N Ft Lauderdale  47  66  50  72 /   0   0   0   0
Pembroke Pines   48  68  49  76 /   0   0   0   0
West Palm Beach  45  64  48  72 /   0   0   0   0
Boca Raton       46  66  49  74 /   0   0   0   0
Naples           44  64  44  73 /   0   0   0   0

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Cold Weather Advisory from 5 AM to 9 AM EST Thursday for FLZ063-
     066.

     High Rip Current Risk through Thursday evening for FLZ168.

AM...None.
GM...None.
&&

$$

SHORT TERM...ATV
LONG TERM....Molleda
AVIATION...ATV