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FXUS62 KMFL 300859

Area Forecast Discussion
National Weather Service Miami FL
459 AM EDT Sun Apr 30 2017

Through Wednesday: Water vapor imagery loop shows longwave
troughing from the southern plains to the midwest, with the 
center of low pressure tightly wound over Western Oklahoma.  
Ridging could be observed ahead of this system over the southeast
CONUS. Surface analysis continues to indicate strong surface high
pressure between Bermuda and the Carolinas. This feature has been 
responsible for the gusty east southeast winds experienced 
overnight and into this morning. Winds have remained elevated 
along the Atlantic coast, generally sustained from 15 to 20 mph, 
with much weaker winds reported across the interior. Boundary
layer mixing from these winds should hinder the development of 
any dense fog, thus have not included mention during the morning grid
production. As models keep the aforementioned surface high 
anchored in place through this evening, surface pressure gradients
will remain tight, and breezy east southeast winds should 
persist. As sufficient low level moisture advects westward, the 
HRRR and Hi- Res WRF prog isolated showers to move onshore along 
portions of the east coast metro. Therefore, have upped PoP 
coverage inland through the next 24-hours to reflect this. Not 
expecting much in the way of significant accumulation through, as
the moisture profile is quite shallow. With east southeast flow 
in place, maximum temperatures may once again creep near their 
daily records over western Collier county, with forecast highs in
the region pushing the low 90s. By Monday, the trough and 
associated cold front will begin to approach the central Gulf. In 
response, the surface high pressure that was responsible for the 
breezy conditions should move further east, away from Florida and 
winds will weaken slightly. Atmospheric moisture will begin to 
rise across the CWA with GFS forecast PW values between 1.5" to 
1.6". Diurnal heating, combined with this increase in moisture, 
will lend to the change of afternoon showers and thunderstorms, 
mainly over the interior. Through mid week, the front to the north
will wash out, but residual moisture should continue chances of 
diurnally driven showers and thunderstorms. Maximum temperatures 
through Wednesday are forecast slightly above normal.

Thursday through early next weekend: Both the GFS and ECMWF deepen
a trough over the central CONUS with an associated cold front
stretching southward over the Gulf. Moist air ahead of the system
will bring an increased chance for showers and thunderstorms
late Thursday and Friday. The GFS has been consistent with the
front pushing through the region late Friday. However, the 
frontal passage with the ECMWF with the last couple runs has been 
anywhere from Friday evening to late Saturday. Still nearly a week
out, confidence on exact timing is relatively low. Have added 
slight chance of showers to the Saturday forecast to account for 
the uncertainty. 


The winds will be easterly around 20 knots over most of South
Florida waters though the remainder of this morning, except for 
the the near- shore Gulf waters and Lake Okeechobee waters where 
the speeds will be 15 to 20 knots. This will allow for 4 to 6 foot
seas in the Atlantic waters and up to 5 feet in the outer Gulf. 
Have extended the small craft advisories for the Atlantic through
mid Monday morning, as latest guidance indicates wind speeds of 
at least 20 KT through this period.


VFR conditions will prevail throughout the next 24 hours. 
The exception will be brief on and off periods of mvfr ceiling 
mainly at the east coast sites although it cannot be totally ruled 
out at APF either. Winds will remain out of the east-southeast 
around 15-20 knots this morning and evening and increase a bit 
during the day while remaining gusty. Dry conditions will also 
prevail as high pressure remains over the region outside very brief 
light rain showers possible along east coast sites. But chances are 
so small that do not even warrant mention of vcsh at this time. Will 
amend if needed.


Strong southeast winds will continue the high risk of rip currents
along the Atlantic beaches through at least Monday morning. The rip
current risk will slowly lower by early next week as winds begin
to weaken. 


High pressure to the north of the region will maintain warm weather,
especially across the western interior, and breezy east southeast 
winds. Wind and RH critical thresholds may be reached this afternoon 
across interior and metro regions of Collier county. If mixing occurs
and dewpoints drop below current the forecast values, RH would
drop below 40 percent, and conditions would then be ripe to 
upgrade to a Red Flag Warning. Otherwise, mainly dry weather is 
expected across the region with a few light showers possible along
the east coast metro. By early next week, increasing moisture 
will result in the chance of afternoon showers and thunderstorms, 
mainly over the interior. 


West Palm Beach  85  76  87  74 /  20  20  20  20 
Fort Lauderdale  85  77  85  76 /  20  20  20  20 
Miami            86  77  86  76 /  20  20  20  10 
Naples           93  73  89  72 /  10  10  20  20 


FL...Fire Weather Watch from 2 PM EDT this afternoon through this 
     evening for FLZ069-070.

     High Rip Current Risk through Monday morning for FLZ168-172-173.

AM...Small Craft Advisory until 8 AM EDT Monday for AMZ630-650-651-

GM...Small Craft Advisory until 11 AM EDT this morning for GMZ676.


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