High Surf Advisory 2, NWS Miami, FL

Area Forecast Discussion
National Weather Service Miami FL
252 PM EST Sat Jan 15 2022

.SHORT TERM (This Afternoon through Sunday)...

A temporary warming trend is well underway this afternoon as surface
high pressure moves east and our wind flow is turning out of the SE
and S ahead of the strong cold front currently over the western Gulf
of Mexico. After highs in the mid 70s this afternoon, low
temperatures tonight will likely occur at or before midnight,
followed by near steady temperatures or even a slow rise the rest of
the night as pre-frontal southerly winds bring strong warm air
advection into South Florida. Timing of the precipitation ahead of
the front still looks to be just beyond tonight, so will keep precip
out of the forecast until Sunday.

Speaking of Sunday, this will be the most impactful period of the
forecast. A strong low pressure system surface and aloft over the
lower Mississippi Valley tonight will make good progress east
tonight, and sweep through the SE U.S. on Sunday. The cold front
timing over South Florida hasn't changed much over the past few
forecast cycles, and by sunrise Sunday the front is forecast to be
near the Tampa Bay area and SW into the Gulf about 100 miles west of
Naples.

Conditions are still expected to support a band of locally strong to
possibly severe thunderstorms just ahead of the front during the day
on Sunday. SPC has a marginal risk of severe thunderstorms for all
of South Florida, with the primary convective mode expected to be a
line/band of strong to damaging wind gusts, along with embedded QLCS
which could result in a low threat of a brief tornado or two. This
is appropriate given the factors working for and against severe
storm development. Working in favor of severe storms tomorrow is a
strong wind profile characterized by 30-40 knot winds and 850 mb and
50-65 knots at 500 mb, yielding bulk shear values of 35-45 knots
ahead of the front, as well as focused convergence just ahead of the
front and upper level divergence SE of a jet max across the northern
Gulf and North Florida. On the other hand, there are several key
factors working against severe storms, primarily rather weak
instability due to modest low level moisture return (i.e., surface
dewpoints in the lower to mid 60s) and poor mid level lapse rates.
Even the most aggressive of the convective allowing models (CAMs)
has most unstable CAPE values struggling to exceed 500 j/kg, so any
severe storm development will have to take advantage of locally
higher instability to maximize the effects of the strong wind
profile and bulk shear. Also, the window for this to occur will be
rather small, probably 2-3 hours ahead of the front at most. The
cold front should move over Naples and areas west of Lake
Okeechobee around 15z-16z, northern Palm Beach County to Cape
Sable around 18z, then off the SE Florida coast by 21z. There
should be lingering areas of showers behind the front, but the
threat of strong/severe storms and locally heavy rainfall should
be over by early afternoon western areas, and late afternoon east.

Winds outside of the storms will also be a factor as the pressure
gradient tightens. Wind gusts at or over 30 mph are expected over
most of the area for a few hours ahead of the front, potentially
approaching wind advisory criteria. For now it appears as if the
duration of the highest wind gusts will not be enough to warrant an
advisory, but nevertheless it will be quite windy.

Temperatures on Sunday will peak in the 70s just ahead of the front,
then likely fall slowly following the frontal passage into the 60s
by late afternoon.

.LONG TERM (Sunday Night through Saturday)...

In the wake of the cold front, blustery NW/N winds will advect a
cooler and drier air mass across South FL through Tuesday as high
pressure builds to our north. Given the dry airmass and influence
of the high, fairly benign conditions (outside of hazardous
marine conditions) will prevail through this period with
precipitation chances near 0, and cloud cover largely limited to
some CAA aloft-induced cumulus on Monday (mostly over the water).
Of note is that the coolest temperatures of the season (thus far)
look likely Mon/Tuesday with 925mb temps dipping to around or
<10C behind a reinforcing shot of cooler air late Monday. These
will support daytime highs in the 60s areawide on Tuesday, with
Tuesday AM's lows largely in the 40s areawide apart from near the
immediate coast (with some shot at upper 30s in the lake region).
Wednesday AM's lows will likely only be slightly warmer as
although the airmass does warm, winds will likely be quite light
and the airmass quite dry with the high just to our north.

The northern high will shift east on Wednesday with the flow
veering more SE-S. This will commence a warming & moistening
trend with high temps on Thursday getting back up to a few
degrees above normal (largely upper 70s, low 80s) and overnight
lows returning to 50s interior and 60s near the east coast.

The next frontal system will approach the area late this week,
although with the mid-lvl wave passing well to our north and the
resultant near zonal flow aloft this front will likely take its
time to reach our area. In addition to the timing uncertainty
there is also uncertainty on whether a frontal wave will develop
over the GOM and impact the area. Consequently went with
mentionable but fairly low-end PoPs for this period. Temperatures
will likely be a few degrees above normal ahead of the front on
Friday with temperatures next weekend depending on whether the
front is able to make a clean pass through South Florida.

&&

.AVIATION(18Z TAFS)...

VFR will prevail through about 09z-12z, then gradually
deteriorating conditions after 12z with the approach of a cold
front and associated band of SHRA/TSRA. MVFR and PROB30 for TSRA
at all sites, starting KAPF around 14z and progressing to after
16z at east coast sites. Further timing adjustments likely as the
front approaches. SE-S wind 8-10 knots, then increasing after 06z
to 12-15 knots with gusts to 20 knots, then S-SW 20 knots/gusts
30+ knots after 14z, with even higher gusts in possible TSRA.

&&

.MARINE...

South winds increasing tonight ahead of the cold front, likely
reaching SCA criteria by midnight, then increasing to 25-30 knots
Sunday morning right ahead of the front. A period of Gale
conditions with gusts to 35kts will be possible on both the
northern Gulf and particularly the northern Atlantic waters on
Sunday both in the prefrontal southerly regime and briefly along
and behind the front. Additionally we could see strong convective
gusts from Showers and thunderstorms ahead of the front on Sunday.

Winds will stay strong and gusty through Monday, then slowly
subside thereafter through most of next week as high pressure
settles into the area. Seas will also build rapidly late tonight
and especially on Sunday, with seas potentially over 10 feet over
the Gulf waters and near 10 feet Atlantic through Sunday night.
Slow subsiding of seas thereafter, but likely staying near 7 feet
in the Atlantic through mid-week in lingering northerly swell.

&&

.BEACHES...

Surf will increase Sunday and Sunday night along the Collier County
coast, and this could raise water levels enough to produce minor
flooding right along the coast in the most vulnerable areas
particularly into the Monday morning high tide cycle (given the
full moon on Monday). Otherwise, the rip current risk will be high
all beaches well into early next week, then remaining elevated
along the Atlantic beaches into mid- week due to lingering
northerly swell.

High surf conditions look possible behind the cold front tomorrow
afternoon for the Collier county beaches, and additionally will be
possible Sunday morning ahead of the front over the Palm Beach
county beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            65  78  59  73 /   0  90  20   0
West Kendall     63  79  56  73 /   0  90  20   0
Opa-Locka        64  78  57  73 /   0  90  20   0
Homestead        63  77  57  73 /   0  90  20   0
Fort Lauderdale  65  78  58  73 /   0  90  20   0
N Ft Lauderdale  65  78  57  71 /   0  90  20   0
Pembroke Pines   63  78  56  73 /   0  90  20   0
West Palm Beach  62  77  54  69 /   0  90  10   0
Boca Raton       64  79  56  71 /   0  90  20   0
Naples           64  76  59  70 /  10  90   0   0

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&

Tonight/Sunday and Aviation/Marine...Molleda
Sunday Night through Saturday...Carr

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Hazardous Weather Outlook for South Florida...UPDATED
National Weather Service Miami FL
1048 AM EST Sat Jan 15 2022

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
160030-
Lake Okeechobee-Biscayne Bay-
Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20 NM-
Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM-
Waters from Jupiter Inlet to Deerfield Beach FL from 20 to 60 NM-
Waters from Deerfield Beach to Ocean Reef FL from 20 to 60 NM
excluding the territorial waters of Bahamas-Glades-Hendry-
Inland Palm Beach-Metro Palm Beach-Coastal Collier-Inland Collier-
Inland Broward-Metro Broward-Inland Miami-Dade-Metro Miami-Dade-
Mainland Monroe-Coastal Palm Beach-Coastal Broward-Coastal Miami-
Dade-Far South Miami-Dade-
Coastal waters from Chokoloskee to Bonita Beach FL out 20 NM-
Coastal waters from East Cape Sable to Chokoloskee FL out 20 NM-
Waters from Chokoloskee to Bonita Beach FL from 20 to 60 NM-
1048 AM EST Sat Jan 15 2022

...Moderate Risk of Rip Currents Palm Beaches...
...A Few Strong to Severe Storms Possible on Sunday...

This hazardous weather outlook is for South Florida.

.DAY ONE...TODAY AND TONIGHT

Rip Currents: There is a moderate risk of rip currents along the Palm
beaches.

Fire Weather: There will be enhanced fire weather conditions today
due to low relative humidity across inland portions of South FL.
However, wind critical thresholds are not expected to be met.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

A cold front will bring the potential for rainfall and strong
thunderstorms on Sunday. Primary potential impacts from the strong
storms will be damaging wind gusts, lightning strikes, and heavy
rainfall. An brief tornado or two cannot be ruled out.

An elevated risk of rip currents will linger through the upcoming
weekend and into early next week. Additionally, high surf and minor
coastal flooding is possible along coastal Collier County on Sunday.

Hazardous marine conditions are expected Sunday through Tuesday in
the wake of a strong cold front across all South Florida local
waters.

Temperatures will be colder early next week in the wake of the cold
front, with possible wind chill values on Tuesday morning in the
upper 30s around Lake Okeechobee.

.SPOTTER INFORMATION STATEMENT...

Widespread spotter activation is will not be needed today.

For more information...visit the National Weather Service in
Miami website at www.weather.gov/miami.

Molleda