Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 210956
Area Forecast Discussion
National Weather Service Melbourne FL
456 AM EST Sat Jan 21 2017
...Threat for Severe Storms Sunday Afternoon into Sunday Night...
...Boating Conditions will Begin to Deteriorate Tonight and Become
Very Hazardous Sunday Afternoon through Monday...
Today/Tonight...Increasing moist southerly flow will produce
patchy fog this morning but dissipate by mid morning. Mid level
ridging will temporarily rebuild over the area and produce more
sunshine than clouds. Increasing S/SW flow will produce a warm day
with near record high temperatures possible in the low to mid 80s.
A mid level impulse/shortwave trough will cross the area this
evening but the assocd band of convection should stay just north
of Lake/Volusia counties. So will keep rain chances out of the
forecast through this evening. Higher moisture will begin to move
in across northern sections from the Gulf late tonight. While deep
convection (thunder) is not expected before sunrise, isolated
showers may affect Lake and Volusia counties toward morning.
Increasing winds above the surface will prohibit fog formation.
Lows temps will moderate a few more degrees holding in the mid
Sunday...Main concern will continue to be the significant threat for
severe weather associated with pre-frontal squall line that will
develop over the eastern Gulf and shift rapidly eastward across the
Florida peninsula. Some uncertainty in exact timing continues, with
latest model guidance trending slightly slower with this system,
indicating arrival of squall line may not reach Lake/Volusia
counties and toward I-4 corridor until later in the afternoon. This
band of convection is then forecast to move quickly eastward across
the rest of east central Florida into the evening and offshore of
the Treasure Coast past midnight.
Breezy/windy southwest flow will allow temps to soar into the low
to mid 80s in the afternoon. Surface heating looks more
substantial across the south where record highs may be in jeopardy.
Combined with dewpoints in the mid-upper 60s, more than sufficient
instability will exist across the area ahead of the squall line.
A 50+ knot low level jet will favor damaging straight line winds
as the main threat with the line of storms. Also, 0-3km helicity
values up to 200-300 m2/s2 will lead to the potential for a few
tornadoes. Due to the faster motion of storms, precipitation
totals will generally be around a half an inch, but locally higher
amounts up to 2 inches will be possible.
Monday-Tuesday...Axis of low aloft will shift east of the state by
Monday afternoon and may generate areas of light rain and isolated
showers during the morning hours. Otherwise cooler and drier air
will build into the area ending rain chances and producing
temperatures closer to normal into early next week. Highs will range
from the upper 60s to low 70s over much of the area each afternoon,
with lows falling as low as the mid to upper 40s. Windy conditions
will occur Monday behind the front, with sustained westerly winds
increasing to around 20-25 mph with higher gusts. Wind speeds will
then decrease into Tuesday ahead of an approaching area of high
pressure from the west.
Wednesday-Friday...High pressure shifts east of the area into mid
week, with flow becoming S/SW and temperatures warming into the mid
to upper 70s Wed/Thu afternoons. A cold front is then forecast to
move southward through the region into Thursday night, bringing with
it only a slight chance for showers and ushering in cooler than
normal temperatures into Friday.
Stratus and fog will affect some terminals thru 14-15Z in
gradually moistening airmass. During the day, prevailing wind
flow will be South to southwest 10 knots, except 10-15 knots
across the southern terminals. Some MVFR cigs may develop aft 06Z
tonight but the primary concern will be increasing wind fields
above the surface which will likely produce non convective wind
shear at MCO/SFB/LEE/DAB.
Today/Tonight...The S/SW pressure gradient will tighten as high
pressure pushes east and away from the area. Speeds of 10-15 knots
are expected during the day, increasing to 15-20 knots early this
evening especially in the Gulf Stream. The gradient will continue
to tighten overnight with 20 knots developing over the offshore
waters late tonight and spread over most of the waters early
Sunday. So have raised a Small Craft Advisory for all the waters
starting at 4am Sunday.
Sunday-Monday...Hazardous boating conditions Sunday are expected
to become very hazardous into Sunday night through Monday. S/SW
winds up to 20-25 knots Sunday will exist across the waters ahead
of an approaching cold front and pre-frontal squall line that is
currently forecast to push offshore from late afternoon through
evening timeframe. Winds will veer to the west and continue to
increase into Sunday night with a Gale Watch/Warning likely needed
through Monday evening as a strong offshore flow continues behind
the passing front. This strong westerly flow will keep highest
seas farther offshore, up to 9-11 feet through Monday night.
Tuesday-Wednesday...Winds gradually decrease out of the west-
northwest Tuesday as high pressure approaches from the west, but
seas will be slow to subside, potentially remaining poor to
hazardous through the afternoon. As high pressure builds across the
area Tuesday night and shifts west of the area Wednesday winds will
continue to weaken with seas falling to 5 feet or less.
Daytona Beach has the best chance to reach or exceed its record
high today, followed by Melbourne:
DAB 21-Jan 83 1990
MCO 21-Jan 87 1929
MLB 21-Jan 85 1963
VRB 21-Jan 86 1990
DAB 22-Jan 83 1937
MCO 22-Jan 87 1929
MLB 22-Jan 86 2007
VRB 22-Jan 86 2007
.PRELIMINARY POINT TEMPS/POPS...
DAB 83 66 83 60 / 10 20 80 80
MCO 84 67 83 61 / 10 10 70 80
MLB 84 68 85 63 / 10 10 50 80
VRB 84 66 85 65 / 10 10 40 80
LEE 82 66 80 60 / 10 20 80 70
SFB 84 66 82 61 / 10 10 80 80
ORL 84 67 82 61 / 10 10 70 80
FPR 83 65 85 63 / 0 10 40 80
AM...Small Craft Advisory from 4 AM Sunday to 9 AM EST Tuesday
from Flagler Beach to Jupiter Inlet out to 60 nm.