Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 192013
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
405 PM EDT Thu Oct 19 2017

.DISCUSSION...

...First Significant Cold Front of the Fall Season Will Push Through
Central Florida by the middle of next week...

Through Tonight...Scattered small showers continue to move quickly
westward in fairly stout onshore flow this afternoon. Expect inland
activity to wane with the loss of diurnal enhancement, but continue
mainly over the coastal counties through the overnight, with a small
chance for a few of them to occasionally make the eastern reaches of
the interior. A pre-first period will address the ongoing activity
through sunset. Otherwise, partly cloudy with mins ranging from the
U60s-L70s over the interior to the M70s along the coast, with U70s
along the immediate barrier islands.

Friday-Friday night...Pattern looks very similar to start Friday,
with scattered showers moving onshore and inland. However, with the
model guidance showing drier air advecting WSW into the peninsula,
expect coverage of lessen as the afternoon progresses. POPs range
from 20 percent north/inland to 40 percent along the Treasure Coast.
A very small threat for a shower or sprinkle may linger into the
overnight hours along the coast. Temps similar to today - maxes in
the L-M80s along the coast and U80s inland. Mins in the U60s-L70s
inland, M70s over the coastal counties, U70s on the barrier islands.

Saturday-Sunday...A considerably drier air mass will be in place
over East Central Florida on Saturday.  Forecast soundings show a
very large subsidence inversion above 850 mb with any available
moisture being confined to the lower levels.  This will greatly
reduce rain chances for much of the area.  The GFS has shown very
good run to run continuity with these lower rain chances and the
latest ECMWF seems to have come on board with this scenario. Have
kept a slight chance PoP for coastal areas from Brevard northward
due to deep layer onshore flow with interior sections remaining dry.
Some enhanced moisture begins to filter into southern areas during
Saturday afternoon resulting in slightly high rain chances from Vero
Beach through southern Osceola county southward (30-40%).  Breezy
conditions can be expected during the afternoon as higher winds
aloft mix down to the surface.

On Sunday, the atmosphere will moisten back up as low-level high
pressure over the Mid-Atlantic states is forecast to be nudged
eastward by an approaching frontal boundary. In response, the local
winds will turn more southeasterly in the lower levels. The increase
in moisture over the area along with cooling temperatures aloft will
lead to showers and perhaps a few thunderstorms during the afternoon
and early evening.  Highest PoPs favor northern areas at 50% (Vero
Beach northward) with 40% farther south.

Monday-Thursday...A potent short wave trough along the central Gulf
coast will eject rapidly NE across the SE CONUS through Monday night,
dragging the first significant cold front of the fall season through
ECFL by Tuesday evening. Increasing moisture ahead of the front will
bring higher rain chances Monday and especially Tuesday, along with
the chance for thunderstorms with the FROPA. Interestingly, the ECM,
which was 1bout 12-18 hours slower than the GFS at 00Z, trended much
faster with both the mid level trough and surface front, and is now
actually a bit faster than the GFS, which actually slowed some. This
faster solution will bring the coolest air felt in east central
Florida since late this past spring starting early Wednesday morning
and continuing into Thursday. After a warm Tuesday afternoon (L-M80s)
mins will fall back to the 60s Tuesday night, with Maxes U70s north
to L80s south wednesday with mins in the M50s to L60s for most of
the area. Slightly cooler on Thursday with maxes in the 70s and mins
in the 50s for all but the immediate coast.

&&

.AVIATION...
Mainly VFR conditions expected. Diurnal heating has allowed SHRA to
develop/push well inland in breezy E/NE flow but should diminish
with sunset. Isold-Sct SHRA will continue to push onshore from the
Atlc into tonight, mainly affecting coastal terminals with brief
MVFR CIGs/VSBYs possible. On Fri, little change expected. E/NE
gradient wind looks a tad stronger esp across the Treasure coast so
breezy conditions expected all areas. Sufficient moisture in the low
levels will support Isold-Sct SHRA pushing onshore and well inland.

&&

.MARINE...Friday through Sunday...Poor/hazardous boating conditions
continue this weekend with seas generally 5-7 ft nearshore and 7-8
ft for the offshore waters. Winds will be around 15 kts for the
nearshore waters and closer to 20 kts offshore.

Monday-Tuesday...Winds will veer to SE-S on Monday ahead of an
approaching strong cold front, which will reach the northern waters
on Tuesday afternoon, and push south of Jupiter Inlet sometime on
Tuesday evening, preceded by a band of showers and storms. Speeds
will run generally 13-18KT with seas 3-4 feet along the coast
and 5-6ft well offshore.

&&

.HYDROLOGY...The middle and upper Saint Johns River basin remains in
flood. River levels are expected to remain nearly steady or only
slightly decrease late this week and into the weekend, even with
some additional light rainfall in the forecast.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  72  83  71  84 /  30  20  20  20
MCO  71  86  69  88 /  20  20  10  10
MLB  77  86  77  85 /  30  30  20  20
VRB  75  85  76  85 /  30  30  20  30
LEE  68  87  69  88 /  10  20  10  10
SFB  70  86  69  87 /  20  20  10  10
ORL  71  86  71  88 /  20  20  10  10
FPR  75  84  76  85 /  30  40  30  30

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory until 4 AM EDT Saturday for Flagler Beach
     to Volusia-Brevard County Line 0-20 nm.

     Small Craft Advisory until 4 PM EDT Saturday for Volusia-Brevard
     County Line to Sebastian Inlet 0-20 nm.

     Small Craft Advisory until 4 AM EDT Sunday for Flagler Beach to
     Volusia-Brevard County Line 20-60 nm-Sebastian Inlet to
     Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-
     60 nm-Volusia-Brevard County Line to Sebastian Inlet 20-60
     nm.

&&

$$

SHORT/LONG TERM...Cristaldi
MID TERM....Combs
AVIATION/RADAR...Kelly



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