Special Weather Statement, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
355 PM EDT Thu Jun 1 2017

.DISCUSSION...

Tonight...
Sea breeze/out flow boundaries pushing well inland on both sides of
the peninsula. Merger btwn the the east and west coast boundaries
should occur well before sunset, with the Orlando Metroplex as the
bull's eye. S/SW H85-H50 steering flow 5-10KTS suggest limited
potential for blow back to the coastal counties. Collision will
occur early enough for the resulting convection to burn through most
of the atmosphere's energy...will include pre-1st pd to cover late
aftn/early evng convection. Activity should be done before
midnight...only brief coastal showers expected along the Treasure
Coast overnight. Min temps near the current dewpoints...L/M70s.

Fri-Sat...
Unsettled WX through late week as a deep mid lvl troffing pattern
over the ern CONUS/W Atlc combines with a weak frontal trof over the
Mid/Deep South to keep the axis of the Bermuda Ridge suppressed over
central/south FL. Wrly flow aloft will pull high moisture from the
GOMex acrs the FL Peninsula...where it will combine with moisture
pooling within the frontal trof to keep deep lyr moisture acrs the
region. PWat values expected to hold in the 2.00"-2.25" range for
much of the upcoming weekend.

Anticipate multiple cloud decks as the the airmass becomes nearly
saturated. This will be a limiting factor wrt sfc heating, despite
the fact that the position of the Bermuda Ridge will maintain a
light S/SW sfc/low lvl flow...one that typically produces abv avg
temps for east central FL. The direct result would be a weak sea
breeze circulation, while the deep saturation lyr implies shallow
lapse rates thru the H85-H50 lyr...AOB 6.0C/KM. Even so, with such
anomalously high PWat values, the necessary forcing to trigger
shra/tsra will be easy to achieve.

Upstream...mid lvl vorticity over the GOMex is triggering plentiful
convection, and the srn branch of the H30-H20 jetstream, while not
particularly strong, will provide a modest amount of upr lvl
divergence. This should be sufficient to maintain 60-70pct PoPs as
both GFS/ECMWF MOS guidance is suggesting. As mentioned, mid lvl
temps/lapse rates not indicative of strong/svr WX...H70 btwn 7-8C
and H50 btwn -7/-8C suggest CG lightning/heavy precip rainfall will
be the most sig WX threats from diurnal convection.

Btwn the cooling effects of the precip and the blanketing effects of
the deep cloud deck, max/min temps will not differ by more than 10-
15F...aftn readings in the M/U80s, mins in the L/M70s.

Sun-Thu...(prev disc)
Models remain in agreement that moisture levels will remain above
normal and support scattered to numerous showers and thunderstorms
each day. Mid and upper level troughing over the eastern CONUS will
maintain westerly flow aloft while the subtropical ridge gets
shunted to our south and east by early next week. While interior
locations will be favored for the greatest shower and storm chances
over the weekend, increasing west winds through the column will
allow for higher rain chances along the coast next week. A weak mid
level trough is forecast to traverse the northern Gulf Coast early
next week and could further enhance rainfall chances into the middle
of next week. Increased cloud cover will keep afternoon temps near
to slightly below normal through the period.

&&

.AVIATION...Thru 02/12Z.
Sfc Winds:
Coastal sites...thru 02/00Z E/SE 8-12KTS...btwn 02/00Z-02/03Z...
bcmg S/SE 4-7KTS...btwn 02/04Z-02/06Z bcmg vrbl AOB 3KTS.
Interior sites...thru 01/22Z bcmg E/SE 7-11KTS...btwn 01/22Z-02/02Z
vrbl 5-8KTS...btwn 02/02Z-02/05Z...bcmg vrbl AOB 3KTS.

WX/Vsbys/Cigs:
Coastal sites...thru 01/22Z sct MVFR shras/isold IFR tsras...btwn
02/00Z-02/03Z N of KMLB chc IFR tsras.
Interior sites...thru 01/23Z sct-nmrs MVFR shras/sct IFR tsras slgt
chc +TSRA with sfc +G35KTS...btwn 01/23Z-02/03Z chc MVFR shras/IFR
tsras.

&&

.MARINE...
Tonight...High pressure ridge across the waters will produce a light
to gentle srly breeze. There will be a chance for storms to push off
the coast through this sunset...mainly north of Sebastian Inlet.
There should be more nighttime lightning storms over the Gulf
Stream. Seas 1-2 feet.

Friday-Tuesday...Bermuda Ridge axis will be the primary WX feature
for the lcl Atlc, maintaining a light to gentle breeze meandering
btwn S/SW at night/early mrng...and S/SE in the daytime/evng with
the seabreeze/landbreeze circulation. Seas 2-3FT. Increased moisture
will lead to increased shra/tsra coverage, some of which will have
the potential to move offshore in the afternoon and evening,
especially north of Cape Canaveral. Southwest flow expected to
become more established early next week as high pressure gets
shunted to our south. This will increase the chance of offshore-
moving afternoon storms over the Space/Treasure Coasts.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  73  84  72  84 /  40  60  30  50
MCO  73  86  71  86 /  40  70  40  60
MLB  73  85  73  84 /  40  60  40  50
VRB  74  85  72  84 /  40  60  40  50
LEE  74  86  73  86 /  40  70  30  60
SFB  73  86  72  86 /  40  60  30  60
ORL  74  86  72  86 /  40  70  40  60
FPR  72  86  73  84 /  40  60  40  50

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.

&&

Short Term/Mid Term...Bragaw
Impact WX/Radar Ops...Spratt