Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 270038

Area Forecast Discussion
National Weather Service Miami FL
838 PM EDT Thu Apr 26 2018

Dry with VFR conditions expected to prevail through the night
with SW to W flow across the region. A surge of moisture from
the south will move into the region enhancing SHRA and TSRA
around mid day Friday. Expect winds to shift southeast in the
afternoon ahead of the front especially for terminals along the
east coast. This will concentrate any convection that develops
along the coast Friday. Included PROB for the chance of TS into
tomorrow afternoon. No mention of SHRA over APF at this time as
confidence is low as the chances for any development near the
terminal at this time remains low.


Isolated showers developing over the Florida Straits will continue
to move northeast tonight. Most of this activity will remain over
the Atlantic waters but can not rule out some near the coast and
moving onshore over Miami Dade county during the overnight hours.
Remainder of the forecast is on track at this time.


.PREV DISCUSSION... /issued 336 PM EDT Thu Apr 26 2018/

Weak high pressure over the region, will breakdown overnight, as
a 250 mb jet and a 500mb trough approach the region. The axis of
the trough looks to move across the region this evening. As it
does, a 75kt jet will also cross the area. This, and some
moisture over the eastern Atlantic waters, may allow for some
showers and thunderstorms to develop. PWATs over the southern half
of the CWA will generally be increasing tonight and tomorrow, to
about 1.5 to 1.75 inches. As moisture increases tomorrow, another,
slightly stronger jet will nose in over the region and exit by
late tomorrow afternoon. However, the GFS is indicating most of
the CAPE will remain generally south of SR-41, and off the
Atlantic coast. So, have a slight chance to a chance of showers
for tomorrow for this area, with a slight chance of thunderstorms.
By tomorrow evening, a stronger 500 mb trough will be moving
across the eastern US. Also, a 100 kt jet at 250mb is progged to
move across Central Florida. At the sfc, a low develops through
the day Friday over the Carolinas and Virginia, moving to the NE,
and merging with an approaching low form the Great Lakes region.
This sfc low will bring a cold front through South Florida Friday
night into Saturday.

The front will not bring much on the way of cooler temps, but it
looks to bring a dry air mass into South Florida. Minimum RH
values are forecast to be in the 30s in the western interior, for
the weekend into the beginning of the week. Also, this will bring
quiet weather to the area, with no rain forecast through the
middle of the week. High pressure does build to the north next
week, bringing more of an easterly flow to the region. This will
slowly increase moisture over the region, and possibly bring some
coastal showers for the latter half of next week to the Atlantic

Seas are forecast to run 1 to 2 feet across the Gulf and Atlantic
waters through the beginning of the week. A cold front may bring
some showers and perhaps a few thunderstorms to the area tomorrow
through Saturday morning. Quiet weather is then forecast through
at least the beginning of the week. High pressure is forecast to
build to the north next week, bringing an easterly flow to the
region, which may build seas in the Atlantic waters to around 5
feet by the middle of the week.

For coastal Collier County, there is the possibility of a Red
Tide outbreak through Sunday evening. See the Beach Hazard
Statement for more details.

Dry weather with mostly sunny skies will prevail through this
afternoon. Light southwest winds should turn southeasterly for the
east coast TAF sites over the next hour or two, as the Atlantic
breeze kicks in. West or southwest breezes are should continue at
KAPF and the Gulf coast. Winds will diminish this evening with
clear skies and light winds overnight.

Low RH values continue tomorrow for the western interior, although
not as dry as today. Then, a cold front Friday night will usher
in another dry air mass to the area for the weekend, and persist
into the beginning of the week. Minimum RH values are forecast
into the low 30s for portions of the interior for the weekend.
Then the trend calls for very gradual moistening across the
region. The 20 ft wind is forecast to be 5 to 10 mph, remaining
well below critical values for the weekend.

West Palm Beach  65  83  66  82 /   0  30  30  10
Fort Lauderdale  70  85  70  84 /  10  40  40  20
Miami            70  86  70  85 /   0  50  40  20
Naples           68  84  69  82 /   0  20  10  10


FL...Beach Hazards Statement through Sunday evening for FLZ069.



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