Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 221142
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
642 AM EST Sun Jan 22 2017

.AVIATION...
Southerly flow around 10 to 15 knots early this morning will
veer to the southwest today as cold front makes its way into
S Fl this afternoon and evening. Strong Low level jet over the
region will keep gusty winds through the evening with gust up
to 25 knots. The threat for strong to severe thunderstorms is
expected this afternoon and evening. Therefore, VCSH has been
added for the afternoon hours for all of South Florida taf
sites, and will leave out thunder conditions at this time.
Showers will transition into thunderstorms late this afternoon
to tonight.

&&

.PREV DISCUSSION... /issued 439 AM EST Sun Jan 22 2017/

DISCUSSION...

..Windy Conditions Across South Florida Today Ahead of Front...
..Severe Storm Potential With Front This Evening and
Overnight...

Today and Tonight:

- Overview: Upper level low moving through Texas today will drive
a surface low into the Deep South, as it interacts with a stalled
frontal boundary along the northern Gulf coast. Driven by a
robust 120-140kt upper level jet, system will deepen as it moves
across the southeast, driving a strong cold front through the
Florida peninsula late today and tonight.

- Winds: Outside of any convection, robust pressure gradient
ahead of the front will lead to strong and gusty synoptic winds
this afternoon. Daytime heating should effectively mix down
stronger winds, Expect sustained south-southwest winds 20 to 25
mph with gusts 30 to 40 mph through the afternoon. A Wind Advisory
is in effect for all of South Florida starting at noon.

- Temperatures: The gusty south-southwest winds and partly cloudy
skies will allow along temperatures to climb into the mid 80s for
most of South Florida. Areas along the east coast may reach into
the upper 80s, flirting with record highs for today.

- Severe Weather Threats: Low level jet already in place will
strengthen later today with impressive 925mb winds of 40-50kts
and 850mb winds 45-55kts into this evening. The forecasted wind
profile still tilts more unidirectional, suggesting damaging
straight line winds as the main threat. However, there remains
enough low level helicity for rotating storms and embedded
tornadoes, especially within any storms that develop ahead of the
main convective line. Small hail and minor urban flooding will
also be concerns.

- Severe Weather Timing: Models have universally slowed down the
approach of the main bands of precip until after sunset. And while
models show the area remaining dry until that time over land, due
to the fairly dry atmosphere currently in place, with near record
temps forecast and a good dynamic profile, can`t rule out
convective development earlier this afternoon. Slowest models
now don`t clear the front until mid Monday morning. However,
consensus remains for the front and strong/severe storm threat to
clear South Florida around daybreak. The best window for severe
weather across South Florida remains from this evening through the
overnight hours.

Monday Through Friday: Upper level and surface low will move up
the eastern seaboard during the day on Monday, continuing to drive
the cold front away from Florida. With the main upper level
trough not expected to cross the state until later in the day and
lingering low level moisture, a few showers will linger across
South Florida through Monday afternoon. It will be windy and
cooler on Monday, with highs in the mid-upper 70s, or about normal
for this time of year.

High pressure will remain in control for much of the remainder of
the week with dry and seasonable conditions, with a gradual warming
trend. Cooler nights Monday and Tuesday with lows in the upper 40s
over the far interior and 50s across the remainder of the region,
then trending warmer into mid-week.

The next threat for rain looks to be with a weaker front late week
with models showing a more pronounced cooldown behind it.

MARINE...Local marine conditions will rapidly deteriorate through
the day as a deepening area of low pressure moves into the Deep
South and brings a strong cold front into the Florida peninsula.
Expect south-southwest winds around 20 knots by daybreak, increasing
to 25-30 knots by this evening. Frequent gusts to gale force are
expected by this evening over the open Gulf and Atlantic, with
potential for sustained gale force winds in the Atlantic overnight.
Dangerous marine conditions are expected to continue through Monday
evening with winds veering west-northwest with time.

Seas build over the local waters with the winds, peaking at 10-12ft
in the offshore Atlantic and 9-13ft in the Gulf on Monday, with
potentially over 15 feet open Gulf waters.

A Small Craft Advisory through today, and a Gale Warning is in
effect from this evening for the open Gulf and Atlantic waters
through Monday night.

BEACH FORECAST...Windy southwesterly flow will bring a high risk of
rip currents to the Gulf Beaches, which may linger through mid week
as seas remain elevated.

With strong onshore flow continuing through Monday, there will be a
risk of coastal erosion and minor coastal flooding of vulnerable
areas along the Gulf Coast of South Florida. The period of greatest
risk will be with high tide tonight and again Monday morning. The
threat at this time looks to low/isolated for a coastal flood
advisory, but this will continue to be evaluated.

&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  87  66  78  57 /  20  80  30   0
Fort Lauderdale  85  69  80  58 /  20  80  30   0
Miami            87  72  77  59 /  20  80  30   0
Naples           81  71  73  60 /  30  80  40  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Wind Advisory from noon today to 7 PM EST this evening for
     FLZ063-066>075-168-172>174.

     High Rip Current Risk from 1 PM EST this afternoon through
     Tuesday evening for FLZ069.

AM...Small Craft Advisory until 7 PM EST this evening for AMZ650-651-
     670-671.

     Small Craft Advisory from 11 PM Monday to 7 AM EST Tuesday for
     AMZ650-651-670-671.

     Gale Warning from 7 PM this evening to 11 PM EST Monday for
     AMZ650-651-670-671.

     Small Craft Advisory until 7 AM EST Tuesday for AMZ610-630.

GM...Small Craft Advisory until 7 PM EST this evening for GMZ656-657-
     676.

     Small Craft Advisory from 11 PM Monday to 7 AM EST Tuesday for
     GMZ656-657-676.

     Gale Warning from 7 PM this evening to 11 PM EST Monday for
     GMZ656-657-676.

&&

AVIATION...67/MT



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