Flood in Florida, December 28, 2019

Area Forecast Discussion
National Weather Service Miami FL
158 AM EST Sat Dec 28 2019

.Short Term...

...Marginal Risk for Excessive Rain Continues...

Today and Tonight...

A upper level ridge continues to sit over the region. At the
surface, high pressure has moved south and is over the western
Atlantic, east northeast of the region. There is ample moisture
wrapping around this high and is bringing rain showers to the
eastern half of the CWA. The sounding shows a strong inversion
above 700mb, and even a weaker one above 850mb. This has kept any
thunderstorms from being able to develop. Most of the tops of the
showers are generally not exceeding 10k ft, although some
isolated cells are nearing 20k ft. Looking at the moisture, the
gradient of PWATs has been mainly from Broward County, north. But,
models are indicating the high will build westward through the
morning and into the afternoon, pushing the showers towards the
interior and west coast later today. This should help to reduce
the flood threat for the east coast metro areas later today.

Regardless, through the morning hours, the showers have been
effective rain producers, with radar well underestimating rainfall
amounts. And, given the now saturated nature of the area, urban
flooding with even modest amounts of rain may be possible.

By early Sunday morning, models are indicating most of the
precipitation should either be off or over the Gulf coast,
allowing for quieter weather for the east coast by Sunday morning.

.Long Term...

Sunday through late week...

On Sunday into Monday, the chances of showers will diminsh somewhat
as mid-level ridging amplifies over the region. This will allow for
some drier air to work its way in. Don't get too used to it because
later Monday into Tuesday, an area of low pressure pinpointing the
Great Lakes Region will slide over to the NE CONUS. A cold front
will extend down from this system in to the Gulf of Mexico and
eventually the Florida peninsula. Both the GFS and ECMWF show the
frontal passage through South Florida late on Tuesday and into
early Wednesday. Isolated to scattered showers will precede the
front thanks to a moist pre-frontal airmass in place across the
region. Forecast PW's soar back into the 1.70 to 2.00 inch range
thanks to moist southerly flow and decent WAA. No thunderstorms
are anticipated with this front.

Behind the cold front, a much drier air mass will move into the
region and it will minimize the shower chances by the middle of the
week. Even though the air mass will be drier, it will not bring much
in the way of cooler air to the region. New Years Day is forecast
to have high temperatures in the mid 70s with morning low
temperatures in the upper 50s to lower 60s. Otherwise, high
temperatures will be in the upper 70s to low 80s and low
temperatures will drop into the low to mid 60s.

By the end of the forecast period, rain chances return as flow veers
back to the E-SE direction, bringing in that all too common Atlantic
moisture. Models are hinting at a stronger front sometime next
weekend but will continue to monitor as we advance into the upcoming
week.

&&

.Marine...
high pressure to the east northeast is set to maintain the east
wind through the weekend. Models are varying with the wind speeds,
and although some of the Atlantic waters are forecast to drop
below 20 kts, there is enough uncertainty, and period where they
do pick back up to over 20kts, that the Small Craft Advisory will
remain in effect through Sunday evening at this time. With the
wind being out of the east, the seas a very gradually subsiding in
the Atlantic, and are only up to around 2 ft in the offshore Gulf
waters. Showers continue to be possible through the weekend for
all South Florida waters this weekend. A cold front next week
should bring a weak, northerly wind back to the area by mid week,
which may cause seas to build slightly. However, current forecasts
keep wave heights from being a significant concern at this time.

&&

.Aviation...
Showers and lower CIGs continue to impact conditions for the
eastern half of South Florida tonight, into Saturday. The forecast
calls for the SHRA to shift westward, eventually impacting APF, as
well as other locations in the western interior. Some of the CIGs
may drop to below IFR levels at times, especially in the western
interior, where some CIGs around 800ft AGL are being reported.

&&

.Beach Forecast...
An easterly wind will keep a High Risk for Rip Currents for the
Atlantic beaches through the weekend. by Monday, the wind should
shift to the south, gradually reducing the risk through the middle
of the week.

&&

.Preliminary Point Temps/PoPs...
West Palm Beach  78  70  79  70 /  50  50  40  20
Fort Lauderdale  78  72  79  71 /  50  40  30  20
Miami            79  72  80  71 /  40  50  30  20
Naples           80  68  80  68 /  40  30  20  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Sunday evening for FLZ168-172-173.
AM...Small Craft Advisory until 7 PM EST Sunday for AMZ650-651-670-
     671.
GM...None.
&&

Marine...13
Aviation...13
Beach Forecast...13
Short Term...13
Long Term...03/Fell

Hazardous Weather Outlook for South Florida
National Weather Service Miami FL
245 AM EST Sat Dec 28 2019

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
282200-
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-
245 AM EST Sat Dec 28 2019

...URBAN FLOODING POSSIBLE, MAINLY EAST COAST METRO AREAS...
...HIGH RISK OF RIP CURRENTS FOR THE ATLANTIC BEACHES...

This hazardous weather outlook is for South Florida.

.DAY ONE...TONIGHT

Rip currents: A High Rip Current Risk is in effect for the Atlantic
beaches.

Flooding: Urban and street flooding is possible for the east coast
metro areas.

Winds and waves: Hazardous marine conditions are expected for the
Atlantic waters and Biscayne Bay.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A high risk for rip currents continues for the Atlantic beaches
through at least Saturday evening.

Heavy rainfall and flooding are possible for the east coast metro
areas through this weekend. There is uncertainty in the timing,
location, and impacts however. Residents and visitors of South
Florida are encouraged to monitor the latest information from the
National Weather Service in Miami.

Hazardous marine conditions will continue for the Atlantic waters
through the weekend.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

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