Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 270748
Area Forecast Discussion
National Weather Service Melbourne FL
347 AM EDT TUE SEP 27 2016
Today...Upper level trough near the FL west coast is forecast to move
eastward over east central FL and move into the Atlc waters this
evening and tonight. The mid level trough looks to be lingering
slightly west of the upper level trough and should provide increased
mid level lift into the late afternoon as it moves toward the area.
Surface low pressure is forecast to move NE off the Carolina coast with
a trailing trough across north FL. Deepest moisture with PWATs to 1.8
to 2.0 inches will remain across the Okeechobee county and the Treasure
coast where higher POPs up to 50 percent range will be advertised
across the far south. Further north GFS has lower pwats in the 1.5 to
1.7 inch range across nrn areas but with cooling mid level temps to -8
to -9 at H5 over portions of the area should see at least isolated to
low scattered coverage of late afternoon convection developing. An
afternoon sea breeze moving slowly inland across the coastal counties
will also provide a focus for some late day storms with activity moving
toward the east coast with mid level WSW flow at 10-15 knots. HRRR and
GFS hint that most robust convection should be across far srn sections
in the late afternoon into the evening, but some drier air at the mid
levels could allow for some isolated strong storms across nrn sections
late as well. Small hail, frequent lightning and gusty winds may occur
with the strongest storms. Highs in the upper 80s to around 90. An east
swell will contribute to a moderate risk of rip currents at the beaches.
Tonight...Isolated to scattered evening convection should focus across
eastern portions of ECFL before pushing off into the Atlantic through
late evening. Mid level trough at H5 will move across the central FL
peninsula overnight which will allow convection to focus ahead of it
across the Atlantic waters for the overnight hours. Lows will be mainly
in the lower 70s.
WED-THU...A weaker frontal boundary will exist across the southeast
U.S. into mid week. Farther north, a deep low pressure system over the
great lakes region digs southward into the Ohio Valley, pushing a
stronger reinforcing cold front into north Florida late Thursday.
A deeper W/SW flow ahead of this boundary and sufficient moisture will
exist over the region for scattered showers and storms to develop and
track E/NE across the central Florida peninsula and offshore into the
afternoon. Low level offshore flow looks like it will remain weak
enough on Wednesday for the sea breeze to form and stall near the east
coast, but sea breeze formation looks less likely for Thursday as
offshore winds strengthen. The presence of the sea breeze on Wednesday
(and Thursday if it can develop) will help enhance any storms near the
coast from any late day boundary collisions, with a few stronger storms
possible. Highs forecast to reach the upper 80s both days with morning
lows in the low-mid 70s.
FRI-MON...Models still not in the best agreement with how far south
front and drier air behind the boundary will make it into central
Florida late Thursday night into Friday. The latest GFS, while not as
far south with the front as 24 hours ago, is still farther southward
with it`s placement than the ECMWF, reaching near Orlando-Cape by
Friday morning. This would lead to lower than normal rain chances
across north central Florida Friday, and currently have rain chances
around 20 percent over this region, up to 30-40 percent farther south.
However due to model inconsistencies rain chance forecast remains more
uncertain for late week.
Still, any decrease in shower/storm coverage will be short lived as
front weakens and west Atlantic ridge axis lifts northward, allowing
for greater moisture increase in developing low level onshore flow into
the weekend. This will increase rain chances to near/slightly above
normal levels through the period.
Highs are expected to continue to reach the upper 80s over much of the
area each day with lows generally in the low to mid 70s.
However, could see min temps as low as the mid to upper 60s early
Friday/Saturday mornings northwest of I-4 if front can make it far
enough south across the region into late week.
Scattered TSRA will dvlp from KMLB-KSUA into late afternoon-early
evening and then move into the Atlc by late evening. A slightly drier
airmass north of KISM-KTIX line should portend lower convective
coverage for areas around nrn terminals this afternoon with Chcs from
20-30 pct. Overall VFR conditions are expected outside of convective
Today and Tonight...Light offshore flow this morning will become
S/SE by late afternoon up to 10 knots. Seas 2 ft near shore to 3 ft
offshore. South winds this evening to 10 knots will veer to the SW-W
overnight. Slight increase in seas heights expected from 2-3 ft
nearshore to 3-4 offshore for the overnight hours. Highest convective
coverage is expected in the late afternoon and evening mainly south of
WED-SAT...Frontal boundary across the Southeast U.S. is forecast to
move into north Florida and potentially as far south as the Cape into
late week. W/SW winds up to 10-15 knots expected over the waters
Wednesday/Thursday and then flow weakens into Friday before becoming
onshore into the weekend as front lifts back northward and fades. Seas
will range from 2-4 feet through the period.
.PRELIMINARY POINT TEMPS/POPS...
DAB 88 72 88 73 / 30 20 50 20
MCO 90 73 88 73 / 30 20 50 20
MLB 88 72 88 73 / 40 30 50 20
VRB 89 71 88 72 / 50 30 50 20
LEE 89 73 87 73 / 20 10 40 20
SFB 90 73 89 73 / 30 20 50 20
ORL 91 74 89 73 / 30 20 50 20
FPR 89 71 88 72 / 50 30 50 20