Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Melbourne Florida
930 am EDT Friday may 22 2015
..poor boating/hazardous beach conditions for Holiday weekend...
..Rain coverage still looks low...
Current...precipitable water values from the 8am/12z Tampa/Cape
Canaveral soundings were 1.54 and 1.74 inches respectively. Both
soundings were indicating wind shifts to the northwest and north in
the lowest level but still westerly from around 850mb/5000 feet and
above. Water vapor satellite imagery shows drier air over the
central and eastern Gulf of Mexico. This drier air mass will be
advected over central Florida during the per the latest run of the
suite of short term hourly models. Would like to jump on lower pop
from Orlando Titusville south based on this thought but the same
models are showing enough afternoon precipitation to keep scattered/chance
of showers with a storm or two from middle afternoon through the early
Sat-Mon...a transition to an easterly flow regime will start Sat as
high pressure bridges dissipating frontal boundary vicinity east
central Florida. Middle level anticyclone is forecast to build over
North Florida and deepen the onshore flow. Some higher moisture
will linger from the front on Sat...then deep layer ridging will
decrease moisture while temperatures aloft steadily warm.
This will cause highest probability of precipitation and main storm chances to shift inland
and to the west side of the peninsula through the period. 00z GFS
MOS values were 20 percent inland and 10-20 percent along the
coast...so will follow decreasing consensus pop trend with maximum of
30 percent inland and 20 percent coast. Main coastal chances
should be night/morning...but with quite low probability of precipitation...will not carry
overnight probability of precipitation over land.
The onshore flow will gradually temper maximum temperatures at the coast to
the middle 80s...and even inland with highs around 90 to the lower
90s. Overnight low will be very mild in the Lower/Middle 70s.
Tue-Fri...little change with the onshore wind flow regime...though
middle level ridge and surface high pressure are forecast to weaken by
late week. Deep layer moisture will remain limited and the GFS shows
a few ribbons of very dry air advecting westward across the
Atlantic and into the local area. This will keep probability of precipitation low...so no
real/true onset of the wet season is evident for east central
Aviation...VFR tempo MVFR until 18z as lowest layers warm up and mix
out overnight moisture in the boundary layer.
Previous aviation discussion
Weak boundary will slide southward across ecfl this
morning/afternoon. Winds will veer northwest/north behind this feature and
eventually north-northeast into the afternoon. Onset of ecsb should be earlier
than the previous day and it will penetrate further inland. Deeper
moisture/heating southward from kmco where greatest afternoon/evening
storm potential will be. Tempo MVFR ceilings/visibilities in vicinity of shra/tsra.
Marine... current buoys reports...009 320 at10 knots and 1 to 2
foot seas. Buoy 010 still southwest 240 at 8 to 10 knots and 3 foot
seas. Both nearshore scripps buoys recording 1 foot seas. The cman
sites at Trident pier and Sebastian Inlet were recording northwest
winds at 5 to 10 knots. Front looks to have push south of Sebastian
Inlet per observations.
Current marine forecast calls for northwest winds early shifting to
the northeast north of the cape and east south of the cape with a
sea breeze component helping to push the onshore wind inland much
further than previous days.
Previous marine discussion
Today-tonight...weak frontal boundary will slip down the coastal
waters this morning/afternoon. SW winds will veer northwest/north behind this
feature...eventually north-northeast through the afternoon...NE this
evening/overnight. Wind speeds may approach 10-15 kts north of
Sebastian Inlet...lighter southward. Seas 2-3 feet today building up
to around 4 feet tonight away from the coast/cape northward. Late
afternoon/evening storms could push off of the Treasure Coast. Winds/seas
locally higher in vicinity of storms.
Holiday weekend-Tue...quite strong high pressure will build to
the middle Atlantic coast Sat then seaward through early next week
with an axis extending into the southeast states. Forecast models
show about a 4 mb gradient along the Florida East Coast which
translates to about a 15 knot onshore flow. The GFS shows a few
periods of 20 knots offshore. Conditions for small craft operation
will be poor and expect that exercise caution statements will be
necessary Sat night into Memorial Day.
Preliminary point temps/pops...
dab 87 72 85 73 / 10 10 20 10
mco 92 73 91 72 / 20 20 30 10
mlb 88 74 86 76 / 30 30 20 10
vrb 89 72 87 74 / 30 30 20 10
Lee 91 72 89 73 / 10 10 20 10
sfb 92 73 88 72 / 20 20 20 10
orl 91 74 88 73 / 20 20 30 10
fpr 89 71 87 74 / 30 30 20 10
Long term/impact weather...bragaw