FXUS62 KMFL 210102

Area Forecast Discussion
National Weather Service Miami FL
902 PM EDT Tue Mar 20 2018

Most of the active weather has been concentrated over coastal
Collier, Lake Okeechobee and north Palm Beach County late in
the afternoon close to sunset. Currently, most of the activity
east has moved over the Atlantic waters while convection west
remains along coastal Collier County. Expect this activity to
continue through tonight and gradually diminish before midnight.
Southwest to west winds will continue to be breezy through the
night and gradually shift northwest as the front moves through
the region into the early morning hours. Behind the front, much
cooler and drier air will infiltrate the region. The threat for
severe weather is becoming less likely at this time but can not
ruled out strong gusty winds with some of the convection towards
the west. This update reflects an adjustment in pops and current
observation trend. Most of the interior, Broward and Miami Dade
metro areas will likely not see any measurable rainfall.


.PREV DISCUSSION... /issued 742 PM EDT Tue Mar 20 2018/

An approaching line of TS, ahead of a cold front, will move
across the northern half of S Florida this evening. Models
indicate the cells should fall apart before affecting areas from
FLL, S. KAPF, KPBI, and KFXE have the best chances at seeing TSRA
this evening, but they should be done by about 05z. Storms may
bring brief IFR conditions through 03z to the Gulf coast and 05z
to the Atlantic coast. VFR behind the cold front passage late
tonight. Gusty wind is forecast for tomorrow.

PREV DISCUSSION... /issued 356 PM EDT Tue Mar 20 2018/

Isolated strong thunderstorms are ongoing across north and central
Florida at this time extending from the Gulf northeast across the
peninsula. This activity will move southeast late this afternoon
into the early evening hours, mainly affecting Glades and the Lake
Okeechobee region. Currently, southwest winds will continue to
gusts 20 to 25 mph with sunny conditions across South Florida
ahead of front. As the front moves further south, better chance
for storms will be possible especially in the late afternoon
closer to sunset. Storm Prediction Centers keeps Glades and the
Lake region under a Slight Risk of Severe thunderstorms late this
afternoon and Marginal Risk north of Marco Island to West Palm
Beach after sunset.

As the upper level low lifts northeast this afternoon and loss of
daytime heating continues, the window for potential strong storms
will gradually close for most areas except portion of the north over
Glades County and the Lake region late this afternoon and early
evening. The primary severe weather threat is expected to be strong
to severe straight line wind gusts. However, hail and rotating
storms can't be ruled out especially if the boundary arrives
slightly earlier and can better utilize daytime heating. Although
there is a relative unstable atmosphere in place with dewpoints in
the low to mid 70s across the region, this low lifts northeast with
subsidence behind it lowering the threat for strong storms late
tonight. Can not rule out still some showers and isolated
thunderstorms possible for the east coast metro as the front moves
through tonight.

WEDNESDAY AND BEYOND: Abundant dry air-mass behind the front will
move into the area keeping dry conditions across S Florida through
the end of the week into the weekend. Daytime highs Wednesday
through Friday will be in the low to mid 70s, climbing back to a
more seasonable upper 70s and low 80s for the weekend as flow veers
easterly. A return of chilly overnight lows is expected with low
ranging from the mid 40s to mid 50s wednesday night and Thursday
night, with a gradual warmup into the weekend.

MARINE...Winds are expected to pick up to 15-25kts out of the south-
southwest becoming northwest behind the front. Expect showers and
storms ahead of and along the front from late afternoon through
early tonight, with the best coverage generally over the Gulf waters
and Lake Okeechobee. The increase in winds will drive an increase in
seas, coming up to 6-7ft over the local Gulf waters Wednesday into
Thursday with Small Craft Advisory in effect. Conditions steadily
improve Friday into the weekend as high pressure moves over the

FIRE WEATHER...Gusty south-southwesterly flow ahead of a frontal
boundary will lead to excellent dispersions across much of South
Florida this afternoon. Showers and storms are expected across the
area this afternoon and overnight with the front, with wetting
rains expected for most of the region.

Another very dry air mass will move into the region behind the cold
front Wednesday. Minimum RH Wednesday afternoon will be in the 30-35
range over parts of the interior, and in the 20-30 percent range
over most of the region Thursday and Friday afternoons, before
increasing to 35 percent or higher this weekend. At this time, winds
above 15 mph are not expected to coincide with the low RH periods,
so headlines are not required.

West Palm Beach 61 77 52 70 / 30 0 0 0
Fort Lauderdale 66 78 55 71 / 20 0 0 0
Miami 66 79 55 72 / 20 0 0 0
Naples 63 74 53 71 / 30 0 0 0


AM...Small Craft Advisory until 8 AM EDT Thursday for AMZ650-651-670-

GM...Small Craft Advisory until 11 PM EDT Wednesday for GMZ656-657-


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