Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 221849
Area Forecast Discussion
National Weather Service Melbourne FL
245 PM EDT Sat Oct 22 2016
Tonight-Sunday...Potent mid-upper level trough along the eastern
seaboard will move east as a mid level ridge builds eastward into
the GOMEX and towards Florida. At the surface, the strong high
pressure ridge moving through the lower MS valley will slided ESE
and begin to weaken. this will result in surface-low level winds
veering onshore through the short range. Model wind/RAOB progs show
a stout H85 subsidence cap will develop late tonight through Sunday.
A shallow marine stratocu deck is expected to develop beneath the
cap and expand over the near shore Atlantic tonight, then start to
push onshore during the early-mid morning Sunday. Like the preceding
event, we could easily see this deck becoming closed-cell and
produce extensive cloudiness, especially near the coast. Because of
this, have bumped up sky cover grids considerably over the inherited
forecast. This will result in the Space/Treasure Coasts having
considerable cloudiness throughout the day, with the deck slowly
expanding inland thereafter.
Local N-NW drainage flow expected to prevail overnight, with temps
dropping into the L-M50s away from the immediate coast, where U50s
and a few L60s PSL thru Tequesta) expected. Maxes Sunday, in the U70s
with a few M70 along the Volusia coast, similar to today.
Mon-Sat...The high pressure ridge just north of the area will weaken
Mon as a frontal boundary pushes off the eastern seaboard.
Strong high pressure over the Great Lakes will build south and east
and produce an increase in E/NE flow midweek. This will modify the
dry airmass and produce isolated to scattered Atlantic showers
pushing onshore the coast from time to time from late Tue onward.
The stronger and more persistent onshore flow will produce milder
max temperatures in the lower 80s and noticeably warmer low temps in
the mid to upper 60s, except lower 70s along the coast.
.AVIATION...VFR. SKC through tonight, then around 12Z-14Z expect VFR
CIGs BKN-OVC035-045 to begin impinging on the VRB-FPR-SUA corridor,
then spread north and a bit inland through the afternoon.
.MARINE...Sunday-Thursday...Winds and seas will relax for a couple
periods with northeast flow 10-15 and seas subsiding a bit to 3 to 5
feet. Reinforcing high pressure is forecast to build south over the
waters by Wednesday and produce a northeast to east wind surge of 20
knots which would build seas and produce hazardous boating
conditions from late Tuesday into late week.
The current SCA and near shore SCEC will expire at 4 PM. A
Cautionary Statement will replace this for the offshore waters, as
well as the nearshore south of Sebastian Inlet, to cover the gulf
Stream closer to the coast.
Minimum RH values will drop below 40 percent northwest of I-4 both
Sunday and Monday afternoons. Gradual moistening of the low levels
in onshore flow will keep RH values above 40 percent from Tuesday
onward. Expect rain-free conditions through Tuesday with low rain
chances returning to the area from mid to late next week.
.HYDROLOGY...The St. Johns River at Astor (2.79ft) will likely
remain near to slightly below flood stage (2.80 ft) today due to
north winds limiting discharge.
At Geneva/above Lake Harney, the St. Johns River (6.88ft) will
remain above Action Stage (6.50ft) through next Wednesday.
.PRELIMINARY POINT TEMPS/POPS...
DAB 55 75 59 78 / 0 0 0 0
MCO 54 77 58 80 / 0 0 0 0
MLB 58 78 63 79 / 0 0 0 0
VRB 59 78 64 79 / 0 0 0 0
LEE 51 78 54 80 / 0 0 0 0
SFB 53 77 57 80 / 0 0 0 0
ORL 54 77 58 80 / 0 0 0 0
FPR 59 78 64 79 / 0 0 10 10
LONG TERM/IMPACT WX....Ulrich