Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 241346
Area Forecast Discussion
National Weather Service Melbourne FL
945 AM EDT SAT SEP 24 2016
...Long period swells will bring an increased risk for strong rip
currents to the local beaches through the weekend...
Current...The weak/broad surface trough that had been over the area
for the past several days has dissipated. The SLP pattern remains
week/baggy across Florida with about a 1 to 1.5MB pressure gradient
from north Florida to the Keys. Visible satellite shows sunny to
mostly sunny skies across the peninsula save for some CI/CS debris
clouds across the southern third to half of the peninsula. Water
vapor imagery and RAP analysis fields show a H30-H20 low centered
over the eastern FL panhandle, extending from SE Alabama/SW Georgia
southward across the eastern GOMEX and the adjacent western FL
peninsula. The low has a W-E elongated reflection at H50.
Morning RAOBs continue to show a decent moisture gradient in place
over the peninsula with 1.55-1.65" PWATs at JAX/TBW and around 2.0"
at XMR/MFL. deep layer flow remains SW, generally light from just
off the deck up to H50, but a little stronger and more backed above
that level, owing to the aforementioned upper low.
Rest of today...Setup looks quite similar to Friday with combination
of deep moisture and weak surface and steering winds. In fact, the
low aloft actually looks like it may be a little more favorably
divergent today. Current POP forecast ranging from 30 north to 50
south looks fine. Am a little inclined to nudge the numbers up by 10
percent across the southern CWA again, but the current forecast is
in decent agreement with surrounding CWAs, so may leave it as is.
Beachgoers are advised that long period swells (3-5 ft/11-12 sec),
emanating from recurving TC Karl, will increase the risk for
dangerous/strong rip currents at the east central Florida beaches
this weekend. Check with your local beach patrol for ocean hazards.
.AVIATION...VFR with some late morning high end MVFR CIGS BKN020-030
developing with diurnal CU field starting ~15Z. MVFR-IFR in SHRA/TS
expected once again by 17Z-18Z, with best chance along the MLB-SUA
corridor through 21Z, shifting toward the inland aerodromes 22Z-02Z.
.MARINE...Another day of minimal wind/chop with a dominant 11-12s
period swell from TS Karl. Local buoys indicate swells of 2-3FT near
the coast and 3-4FT farther offshore, which is right in line with
the current forecast. Both the NWPS and WNAWAVE guidance suggest an
increase in seas of about 1FT late tonight before waning on Sunday,
as Karl accelerates NE across the north Atlantic. No changes to the
.PREV DISCUSSION... /issued 345 AM EDT Sat Sep 24 2016/
Winds will again become L/V this evening/overnight. Highs today will
stay persistent with U80s to near 90 degrees along the east coast
and L90s into the interior. Overnight lows keeping in the L-M70s.
Sunday...Moisture profiles will remain similar to recent days with
deepest moisture lingering from Okeechobee county to the Treasure
coast with PWATs from 1.8-1.9 inches. Aloft a mid/upper level low
will elongate near the FL panhandle with light WSW-SW winds at h5
and light southerly flow aloft. Sfc high well north of the area will
allow low level flow to turn onshore albeit fairly light. Will fcst
40-50 pops far srn areas and 30-40 pct across the nrn CWA. Highs
upper 80s coast to around 90 across the interior. Long period swells
from Karl will keep the rip current risk elevated at east central FL
Monday...Light onshore flow will veer to the east-southeast in the
afternoon with models progging lower PWATs from Orlando northward
around 1.6 inches and deeper moisture across srn sections once
again. Will keep POPs around 40 percent northern sections mainly
with scattered convection developing in the mid to late afternoon.
Rain chances in the 40-50 percent range across srn sections where
some convection may begin by early afternoon with deeper moisture
present. Highs upper 80s coastal to around 90 for the interior.
Tue-Wed...Low level flow will continue to veer to SW Tuesday and WSW-
W on Wed ahead of an approaching frontal boundary which will move
toward N Fl Tue aftn and the nrn peninsula by Wed evening.
Increasing moisture levels ahead of the front will support mainly
diurnal scattered showers and storms that will last into evening
each day. Will keep POPs in the 40-50 percent range for now.
Thu-Sat...00Z models begin to diverge for late week forecast with
00z GFS latching closer to yesterday`s more progressive ECM solution
which portends sfc high pressure quickly bridging the front late
week turning low lvl flow onshore by Thu afternoon into weekend with
increasing moisture and scattered to numerous Atlantic showers (and
isolated lightning storms) moving onshore to start next weekend.
Will follow closer to GFS solution at this point which is supported
by WPC preference with 00Z ECM looking like an outlier from recent
other global model runs. Will keep rain chances in the scattered
range Thu-Fri and advertise slightly higher POPs by Saturday with
GFS indicate deep moisture entrenched and stronger onshore low level
flow as pressure gradient tightens some. This type of pattern can be
supportive for coastal heavy rain events for ECFL...though since
this is out at Day 6-7 still have plenty of time to refine any
potential for locally heavy rain next weekend.
.AVIATION...Mainly VFR outside of afternoon/evening convection.
ISOLD-SCT showers/storms will be the main focus again this
afternoon/evening as the ECSB forms and pushes slowly inland. Higher
deep layer moisture continues across the Space/Treasure coasts.
Tempo MVFR with showers/storms, especially south of KMCO.
.MARINE...Today-Tonight...A general light offshore flow early today
will become light onshore this afternoon surrounding ECSB
development and push inland. A light offshore flow will develop
again later this evening/overnight.
TC Karl will re-curve away from the area, sending a small-moderate
easterly long period swell (11 seconds) into the local waters. Seas
generally building to 3-4FT near shore and 4-5FT offshore north of
Showers and storm coverage will be isolated to scattered with a few
of these cells potentially moving off of the east coast this
afternoon/evening, especially south from Melbourne.
Sunday...NE-E winds 5-10 knots expected with an east swell to 3-4 ft
near shore and 4-5 ft well offshore. Scattered showers and storms
expected mainly across the waters south of Cocoa Beach.
Mon-Wed...East winds Monday will veer to SE tuesday and SW-S Wed.
Swells from Karl will diminish with seas dropping back to 2 ft near
the coast and 2-3 ft offshore.
.PRELIMINARY POINT TEMPS/POPS...
DAB 88 72 88 72 / 30 20 30 20
MCO 91 73 91 73 / 30 20 40 20
MLB 89 73 89 74 / 30 40 30 30
VRB 88 73 87 72 / 40 40 40 40
LEE 92 73 91 73 / 30 20 40 20
SFB 91 73 91 73 / 30 20 30 20
ORL 92 75 91 74 / 30 20 40 20
FPR 88 72 88 72 / 40 40 40 40