Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 171138
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
638 AM EST Wed Jan 17 2018

.AVIATION...
VFR with a dry cold front passing through the region later this
evening into tonight. Increasing cloud cover as the day continues
with winds picking up out of the NNW late in the evening into the
overnight hours. A clearing trend and some gusty NNW to NW winds
expected on Thursday.

&&

.PREV DISCUSSION... /issued 429 AM EST Wed Jan 17 2018/

DISCUSSION...
Latest water vapor loop shows a deep trough centered over the
Tennessee Valley with mid and upper level moisture streaming
northeastward, out ahead of the feature. WPC surface analysis
depicts a well defined cold front draped southward from the
apparent low, moving swiftly across the eastern Gulf of Mexico.
This feature will play an important role in the weather across our
CWA over the next 24-hours. Early this morning, north northeast
flow continues to filter in sufficient low level moisture from
over the Atlantic to keep temperatures from plummeting, similar
to early yesterday morning. As we progress through the day,
however, models agree in pushing the aforementioned front
southeastward across the Florida peninsula. GFS forecast PWAT
values are still below an inch, so not expecting much in the way
of thick clouds or precipitation to develop. Maximum temperatures
will be a few degrees cooler than yesterday, mainly in the low
70s. By late this afternoon, after peak heating, winds will back
to the north northwest behind the front. This flow pattern will
advect much cooler and drier air in to our region. Mostly clear
skies should enhance radiational cooling tonight as temperatures
begin to plummet after sun down. Areas west of Lake Okeechobee
will be subject to the lowest minimum temperatures, down into the
low to mid 30s. Issued a Freeze watch tonight for Glades County,
though portions of Hendry County may be close to approaching
criteria too. In addition, wind speeds between 5 to 10 mph could
continue through the night, which would then introduce wind chills
in the mid 20s/lower 30s for the northern interior and Gulf
regions. A Wind Chill Advisory will more than likely be issued
later today to cover these areas. Along the east coast metro,
minimum temperatures should be more moderate with forecast
mins in the upper 40s and wind chill values in the low to mid
40s.

Thursday through this weekend: Thursday into Friday, mid range
models build surface high pressure back over the southeast CONUS.
This will veer low levels winds back to the north northeast
across South Florida. Once again, the atmosphere will be too dry
to produce any precipitation, with partly cloudy skies prevailing.
Maximum temperatures on Thursday in the upper 50s for the
northern interior to low to mid 60s along the east coast metro,
values 10 to 15 degrees below seasonal norms. Maximums will
slowly begin to rebound on Friday as flow shifts more easterly.
Over this weekend, a weak shortwave drifting eastward across the
Gulf should allow for deeper moisture to move northward over South
Florida. This increase in moisture and weak instability may bring
a better chance for showers, though confidence of occurrence is
still low to moderate.

MARINE...
A cold front will pass across the waters later today,
followed by strong northerly winds that will overspread the
region this evening and into tonight. Small Craft advisories are
in effect for both the Gulf and Atlantic waters for breezy
northerly winds and hazardous seas. Conditions will show signs of
improvement by late Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  73  44  61  49 /  10   0  10  10
Fort Lauderdale  72  46  62  52 /  10   0  10  10
Miami            75  48  64  52 /  10   0  10  10
Naples           72  39  59  42 /   0   0   0   0

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Freeze Watch from late tonight through Thursday morning for
     FLZ063.

AM...Small Craft Advisory from 7 PM this evening to 4 PM EST Thursday
     for AMZ650-651-670-671.

GM...Small Craft Advisory from 4 PM this afternoon to 10 AM EST
     Thursday for GMZ656-657.

     Small Craft Advisory from 4 PM this afternoon to 1 PM EST
     Thursday for GMZ676.

&&

DISCUSSION...27/JT
MARINE...27/JT
AVIATION...02/RAG
BEACH FORECAST...27/JT



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