Special Marine Warning 125, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
317 PM EDT Tue Jul 27 2021

.DISCUSSION...

...Peak Heat Indices 101-106F Next Few Afternoons...
...Locally Heavy Rainfall Remains Possible Next Few Days...

Current-Tonight...An early initiation of showers and storms this
afternoon across east central FL with many boundary collisions
occurring. Storm steering flow into this evening will be weak and
generally of a southerly component (5 kts), though with such a light
component larger/stronger boundary collisions will allow for storm
movement to be erratic at times. PWAT values will average well in
excess of 2 inches areawide. Temperatures at 500 mb remain fairly
warm at -5.5C to -6.5C. While lapse rates are not that impressive,
parameters continue in place for SCT-NMRS (50-60pct) convection. A
few storms could be strong with primary threats of frequent cloud to
ground lightning strikes, gusty winds of 40 to 45 mph and torrential
downpours leading to isolated rainfall totals of 1 to 3 inches. This
may cause localized flooding of roads and other poorly drained urban
and low-lying areas.

The Atlantic high pressure ridge axis remains suppressed across
south Florida. Light morning winds have become ESE/SE near the coast
with sea breeze formation and slow penetration inland. The 915 MHZ
USAF Cape wind profilers continue to show a dominant SWRLY direction
above the surface thru 10.0 ft, though speeds remain fairly light,
generally 5-10 kts.

Lingering early evening convection will weaken and/or move offshore
by midnight. Mins in the M70s for most areas. Cloud debris will
gradually diminish thru the night. Offshore surface wind component
light.

Wed-Tue...Previous Modified...The subtropical ridge remains centered
well east for much of the week, then builds into the central
Atlantic Ocean this weekend into early next week. A far western
extent of the ridge axis will remain across South Florida through
the period. Aloft, weak ridging is forecast with no significant
features. A stalled weak front across northern FL is expected to
linger through late week before dissipating this weekend. This could
cause an enhancement to our rain chances late this week, as deep
moisture continues to be drawn up into east central Florida.

Light winds are forecast to prevail across Central FL for much of
this week into next weekend, and with the ridge axis well to our
south expect light SW to W flow across Central FL. The sea breeze
combined with deep moisture and daytime heating will be the driver
of showers and lightning storms each afternoon, as rain chances
range from 50-60 percent each day.

Frequent lightning strikes, torrential downpours, and gusty winds
will continue to be the primary threat from storms. There will be a
higher threat for localized flooding due to slow storm motion, with
some storms likely able to produce 1-3 inches of rain in a 1-2 hour
time period. Afternoon highs should reach the low 90s along the
coast and low to mid 90s inland, with peak heat indices between 101
and 106 each day. Remaining muggy overnight as lows settle in the
mid to upper 70s.

&&

.AVIATION...Earlier start to SHRA/TSRA this aftn along with higher
coverage. Numerous boundary collisions will continue to generate
convection through 00Z so TEMPO IFR/MVFR for all terminals. Then
mainly VFR aft 00Z with light SW flow around 5 knots. On Wed,
westerly flow 5-10 knots should bring scattered SHRA eastward by 15Z-
16Z developing into TSRA thereafter, esp when they collide with the
east coast sea breeze in the aftn.

&&

.MARINE...Afternoon-Tonight...S/SSE (ESE at coast) winds around 10
kts. The wind component will switch back to SSW/SW this evening and
overnight. Afternoon and evening showers and storms along the coast
could last into the evening and pose a threat across the
Intracoastal Waterway and very near shore Atlc waters. Storm
steering flow will generally be out of the south or SSW and could be
erratic at times due to the weak nature (5 kts). Seas generally 2-3
ft but could build to 4 ft well offshore (north of Cape) and, of
course, will be locally higher invof stronger storms.

Wed-Sun...Previous Modified...Favorable boating conditions are
forecast to persist across the local waters through the week and
likely into next weekend outside of any shower/storm activity. Winds
will generally be light, becoming southeast to south at 10-15 knots
behind the sea breeze each afternoon. Seas around 1-2 feet, with 3
feet possible well offshore. The highest coverage of afternoon
storms will focus along and west of I-95, though there will still be
some activity across the Intracoastal Waterway and very near shore
Atlc waters. Weak west winds and some dominant boundary collisions
will also nudge a few storms toward the coast late each afternoon
and evening. Cloud-to-ground lightning strikes, torrential
downpours, and a few wind gusts to 35 knots will be the main threats
to mariners.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  75  91  75  90 /  30  60  30  60
MCO  76  92  76  93 /  30  60  30  60
MLB  76  92  76  91 /  30  60  30  60
VRB  74  92  74  92 /  20  60  30  60
LEE  77  92  77  92 /  30  60  20  60
SFB  76  92  76  92 /  30  60  30  60
ORL  78  92  78  93 /  30  60  30  60
FPR  74  92  74  92 /  30  60  30  60

&&

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

ALL FORECAST GRIDS...Sedlock
RADAR/IMPACT WEATHER....Negron
AVIATION...Kelly