Special Weather Statement, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
331 PM EDT Sat Jul 11 2020

.DISCUSSION...

...Numerous Lightning Storms and Hot Conditions Through This
Evening...

Rest of Today-Tonight...Deeper moisture has contributed to higher
coverage of lightning storms this afternoon. The east coast sea
breeze did briefly develop along much of the coast, which will
help enhance storms as outflow boundaries and the sea breeze
collide. Main threats from storms today are frequent lightning
strikes, gusty winds of 40 to 50 mph, and torrential downpours.
Rain accumulations of 2-3 inches in an hour or two are possible,
resulting in localized flooding such as ponding of water on
roadways and poor drainage areas.

Hot and muggy this afternoon. Even as rain drops temps back into
the upper 80s it'll stay uncomfortably muggy due to high
humidity. Most have seen peak heat indices around 105-107, with
Melbourne/Ft. Pierce reaching heat index of 108-110 for a short
period early afternoon. These heat index values are typical for
July in central FL, and a Heat Advisory was not warranted today
for such a short duration of heat indices above 108.

High rain chances persist through sunset, especially along the
coast where showers and lightning storms likely to linger to or
just past sunset. Storms to push offshore by late evening with dry
conditions across the region after midnight. Mild overnight
temperatures in the mid to upper 70s.

Sunday-Monday...(Modified Previous Discussion) Florida is centered
between two 500mb ridges, over the Atlantic and western TX, with
the southernmost reach of a deep upper trough extending into the
eastern Gulf of Mexico. This trough and associated surface front
will back westerly winds to the southwest, offering a gradual
increase in high temperatures both Sunday and Monday, approaching
the mid 90s near the coast. Combined with high humidity levels
will create feels like temperatures in the low to mid 100s. Heat
relief will reside overnight, with lows dropping to the low to mid
70s each night.

The surface front will also bring in drier low/mid-level air,
especially along and north of I-4 on Sunday, and farther south
towards Melbourne area on Monday. The westerly wind component
continues to favor shower and storm development along the coast,
though the deeper moisture to be confined south of the Orlando
Metro area. This leads to a north/south rain chance gradient
ranging from 30-40 percent along and north of I-4 to 50-60 percent
from Lake Okeechobee to Treasure Coast on Sunday.

Monday's setup mimics Sunday, however slightly lower coverage is
anticipated as drier air drags southward. Only around a 20-30
percent rain chance from Orlando to Titusville north. The higher
threat for afternoon lightning storms confined from Yeehaw
Junction to Vero Beach south, around 50 percent chance of rain.

Tuesday-Friday...(Previous Discussion) A pattern shift will
arrive mid- week as the Atlantic ridge axis builds closer to the
peninsula, due to the eroding of the upper trough and development
of upper ridge across the Midwest and Deep South. Locally, this
will transition the period of westerly flow to easterly, with rain
chances favoring interior locations from Wednesday onward.

Guidance still running a bit high with rain chances, so have
capped near 60-70 percent through the remainder of the week.
Anticipate continued sea breeze and boundary driven convection,
with typical coverage seen in mid July. The shift in the wind
pattern will aid in temperature regulation, with highs in the mid
90s on Wednesday creeping lower each day through the end of the
week, with seasonal low 90s returning. Nighttime lows hold steady
in the low to mid 70s.

&&

.AVIATION...

Numerous ongoing lightning storms necessitate a long window for
VCSH/VCTS in the TAFs once again. Included a TEMPO with MVFR
CIGS/VIS through 20/21Z for inland sites, and through 22Z along
the coast. Additional showers and storms will be possible through
midnight. VFR conditions expected outside of convection through
the TAF period. Tomorrow, winds will be SSW/WSW around 10KT.
Included VCSH starting at 14/15Z for the interior sites.

&&

.MARINE...

Rest of Today-Tonight...Numerous offshore moving lightning storms
are ongoing and are expected to persist into this evening. These
storms will impact most of the east central Florida Intracoastal
Waterway and nearshore Atlantic waters. Storms will be capable of
producing wind gusts up to 40 knots and frequent lightning
strikes. After storms dissipate this evening, southwest winds
10-15 knots overnight with seas 2 feet nearshore and up to 3 feet
offshore.

Sunday-Thursday...Generally favorable marine conditions persist
through midweek as surface ridge axis remains south of our area.
This maintains westerly flow regime across the Atlantic waters.
Wind shifts expected each day with the development of the sea
breeze circulation, but generally remaining at 10-15 kts. Seas of
2-3 feet may build slightly up to 4 feet in the far offshore
waters on Sunday into Monday, but diminish through midweek.
Scattered to numerous showers and storms expected to develop in
the early to mid afternoon, lasting through the evening hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  75  94  73  95 /  20  20  10  20
MCO  76  94  75  95 /  20  40  10  30
MLB  76  91  75  92 /  30  50  20  40
VRB  76  92  74  93 /  30  50  20  50
LEE  76  94  75  95 /  20  20   0  20
SFB  76  94  76  96 /  20  30  10  20
ORL  77  94  76  96 /  20  40  10  30
FPR  75  92  74  93 /  30  50  20  50

&&

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

Rodriguez/Cristaldi/Watson