Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
8 PM EDT Wednesday may 27 2015
..rough surf and elevated rip current threat continues into late
..a better chance for afternoon showers and storms this weekend
with rain chances possibly increasing further early next week...
Current-overnight... update to remove the rough surf and elevated
rip current threat headline from the coastal zones. The hrrr and
local WRF models all suggesting isolated light rain showers moving
east to west across the coastal waters...coming shore as sprinkles
that may reach well past Interstate 95 from Brevard County to Martin
County before dissipating. This is still in line with the current
forecast. After midnight winds around 15 miles per hour diminish to less than 5
miles per hour away from the coast and around 5 miles per hour in the coastal counties.
Aviation...after 28/04z few030 interior sites...sct-bkn040 with vcsh
ktix south at the coast.
Marine...buoys recording east winds around 15 knots and seas 3 to 4
feet just off the beach per the scripps buoys and 3 to 5 feet from
buoy 009 out to buoy 010. Both the hrrr and local wrf's suggesting
easterly winds averaging out to 10 to 15 knots overnight. The east
winds over a long east fetch in the Atlantic will continue to
produce 3 to 5 foot long period (swell) seas overnight.
Climate...warm low records for today, may 27th...
Dab 75 (1998)
mco 76 (1953)
mlb 76 (1986)
vrb 79 (1991)
This afternoon-tonight...weak vorticity maximum/low level trough has brought
a local moisture enhancement into the waters this
afternoon...setting off a few showers over the local Atlantic.
Otherwise cumulus development is fairly meager across the peninsula as
expected given the dry air and low level inversion.
Will continue to see a few Atlantic showers the remainder of the
afternoon into the overnight hours with some reaching the coast at
times. Have added the mention of sprinkles for this afternoon and
tonight along the space and Treasure coasts...but the probability of
any accumulating or significant precipitation remains low. Interior areas
will remain dry.
Overnight lows remain mild at the coast in the middle-upper 70s with
upper 60s/low 70s over the interior with drier air.
Thursday... upper level ridge overhead starts to break down though
its initial effects on our sensible weather will be minimal. Models
still show significant dry air advection from the east with precipitable waters
remaining around 1" or less and a very suppressed airmass. This will
preclude any significant precipitation across the region. A few vorticity
maxes/convergence bands moving into the easterly flow may bring a
few light showers/sprinkles to the waters at times which may reach
the coast...but impacts remain too low at this point for precipitation
mention. Afternoon highs continue in the middle 80s coast and upper
80s/around 90 inland.
Rough surf and elevated threat for life threatening rip currents
will remain a concern along area beaches.
Thursday night-Friday night...strong middle level ridge will remain quasistationary
along southeast Atlantic Seaboard...while slowly weakening through late Friday.
Leading edge of enhanced moisture embedded in deep easterlies will
push westward along the central/southeastern coast by late Thursday night and
then spread westward across the area throughout Friday. This will lead to
higher rain chances...mainly rain showers with just a slight chance for ts as ecsb
will be diffuse and fast moving in blyr flow of 15kt or so.
Activity should move west of the area by before sunset with small
chance for overnight coastal rain showers returning. Highs middle 80s coast to
around 90 interior. Mins in the u60s-l70s Thursday night and l-m70s Friday
night in slightly stronger onshore flow behind Erly moisture surge.
This weekend...aforementioned middle level ridge to the NE of Florida will
flatten/collapse...leaving light southwesterly Middle Flow over Florida between its
carcass and a middle level trough developing over the lower MS valley.
Weakening Atlantic surface ridge will still provide a lighter onshore flow
and sufficient moisture/mean precipitable water for scattered diurnal convection...with
slightly higher chances over the interior. Temperatures remain reasonably
close to climatology...M-u80s near the coast and near 90f inland.
Mins\generally in the l70s...a few m70s mainly beachside areas.
Mon-Wed...local weather pattern will become unsettled early next week as
falls extend east and southeast-wd from a slowly evolving cutoff low which is
prognosticated to drop very slowly southward through the lower MS valley during this
period. There is remarkable agreement through days 5-8 between the
ecm and GFS at the surface and h50...until Wednesday (and beyond) as the ecm
fails to show the surface pressure falls over the Bahamas like the GFS.
Also of note is the similarity in the synoptic evolution prior to
the formation of T.S. Ana just off our southeast coast early this month as
well as the fact that the GFS outperformed the ecm in having initial
baroclinic low development closer to shore. In any event...scenario
points toward increasing rain chances through the middle of next week...
especially along the coast...with some potential for locally heavy
downpours if the models hold serve. Of course...any potential low
development is a good 6 days away...and the Standard caveats apply
west/r/T model uncertainty out at that time range.
Aviation...prevailing VFR. Occasional MVFR ceilings with Atlantic cloud
bands/sprinkles moving into the coast this afternoon and evening and
again across the region between 12z-15z with daytime cumulus development.
Overall dry forecast continues into Thursday.
Tonight-Thu...little change in the overall pattern and conditions
over the local Atlantic over the next day as ridge axis remains to
our north keeping region in moderate easterly flow. Overall speeds
10-15kts with higher gusts up to 20kts at times...especially late
tonight/Thursday morning with nocturnal wind maximum. The long easterly
fetch will continue to slowly build seas with 3-4 feet this afternoon
building up to 5 feet offshore tonight in a fresh swell. Will see
dominant wave periods lengthening to around 8 second.
Fri-Mon...slight reinforcement of onshore winds early Friday morning
with speeds remaining in the 10-15kt range Fri-Sat...with surface winds
weakening slightly as they veer to southeast early next week. Potential
for deep layer cutoff low to send some swell our way through this
weekend as it slowly drifts northward along 60w from near 30n. Seas
generally in the 3-4ft range near shore and around 5 to occasionally 5-6ft
Preliminary point temps/pops...
dab 71 85 70 85 / 10 10 10 30
mco 71 88 69 88 / 0 10 10 30
mlb 74 85 72 85 / 10 10 20 30
vrb 74 86 70 85 / 10 10 20 30
Lee 72 90 69 90 / 0 10 10 30
sfb 71 87 67 88 / 0 10 10 30
orl 71 87 70 87 / 0 10 10 30
fpr 75 86 69 85 / 10 10 20 30