Area Forecast Discussion
Issued by NWS Miami, FL

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171
FXUS62 KMFL 121458
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
958 AM EST Tue Dec 12 2017

.UPDATE...
12Z MFL sounding and TPW imagery show that dry air continues
over South Florida today. Temperature forecast for today appears
to be on track, with highs expected to rise into the low 70s for
most locations this afternoon. Cold front over northern Florida
expected to track through South Florida overnight. There should be
some low clouds during the first part of the night with the
frontal passage, but skies should clear out a few hours before
daybreak. I expect low temperatures tonight/Wednesday morning to
be a few degrees warmer than last night/this morning due to a more
moist lower troposphere and stronger low-level winds. However, if
the clouds clear out sooner than expected, and if the winds
become light enough, then it could get 1 or 2 degrees colder late
tonight than currently forecast. For this update, I nudged
tonight`s forecast low temperatures down 1 degree from the
previous forecast for eastern and interior portions of South
Florida. Still do not expect it to be quite as cold as this
morning.

&&

.PREV DISCUSSION... /issued 556 AM EST Tue Dec 12 2017/

AVIATION...
VFR through the period. The wind is forecast to pick up late this
morning out of the west to northwest, at 10 to 15 kts. A cold
front will move through tonight, shifting the wind to the
northwest overnight, but otherwise, no affect on the weather.

PREV DISCUSSION... /issued 406 AM EST Tue Dec 12 2017/

DISCUSSION...
Latest IR satellite imagery shows mostly clear skies
across Southern Florida, with the exception of a few quickly
moving cirrus clouds. A relatively dry atmosphere, combined with
mostly clear conditions, will lead good radiational cooling
through early this morning. Minimum temperatures are forecast to
drop into the upper 30s around the Lake Okeechobee region, with
40s to around 50 elsewhere. Isolated frost may be possible west of
the lake, but not widespread enough to warrant an advisory. For
the remainder of today, a broad trough draped over the southeast
CONUS will maintain westerly flow in the low levels. Mostly sunny
skies and dry weather should prevail with dewpoints struggling to
reach the mid 50s. A dry frontal passage late this afternoon into
tonight should reinforce west and northwest flow.

Wednesday through Friday: Through the mid range forecast, broad
troughing will remain in place over the peninsula. This pattern is
expected to continue the north or northwest flow, along with dry
and cool conditions. Wednesday, behind the aforementioned dry
front, maximum temperatures are only forecast in the mid to upper
60s, around 10 degrees below seasonal norms, before rebounding
slightly on Thursday. Minimum temperatures both Wednesday and
Thursday are may only reach the upper 40s to lower 50s, around 10
to 15 degrees below normal.

Friday night through Saturday: Long range models have slightly
different solutions for the extended. The GFS drops a cold front
down from the northwest Friday night into Saturday, generating
enough lift and instability ahead of the front for a chance of
showers over the whole CWA. Meanwhile, the ECMWF washes the front
out over central Florida and keeps our area dry. For now, have
compromised with low end PoPs during this time frame, to account
for the rather uncertain path and intensity of this front.

MARINE...
A dry frontal passage will bring a surge of west to
northwest winds this afternoon into tonight, with small craft
advisories hoisted for the outer Gulf waters and for the waters
off Palm Beach county. Moderate rip currents are also expected
along the Gulf Coast, due to the breezy west northwest winds.
High pressure quickly rebuilds across the state on Wednesday with
diminishing winds. No significant rain chances are forecast
through most of the upcoming week.
&&

.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach  71  47  67  45 /   0   0   0   0
Fort Lauderdale  72  51  67  50 /   0   0   0   0
Miami            72  52  69  49 /   0   0   0   0
Naples           71  54  65  48 /  10   0   0   0

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 7 PM this evening to 4 AM EST
     Wednesday for AMZ650-670.

GM...Small Craft Advisory from 3 PM this afternoon to 4 AM EST
     Wednesday for GMZ676.

&&

UPDATE...98/ABH
DISCUSSION...27/JT
MARINE...27/JT
AVIATION...13







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