056
FXUS62 KMLB 201424
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
1024 AM EDT Sat Jul 20 2024

...New UPDATE...

.UPDATE...
Issued at 1024 AM EDT Sat Jul 20 2024

KEY MESSAGES...

-Scattered to numerous (50-80%) showers and storms expected this
 afternoon and evening, with greatest coverage along and northwest
 of the I-4 corridor. Locally heavy rainfall and minor flooding
 of urban or poor drainage areas will be possible.

-Hot and humid conditions this weekend, with highs in the low to
 mid 90s and peak heat indices around 103-107F, will continue an
 elevated risk of heat stress during the afternoon hours.

-Drier and somewhat dusty airmass associated with the Saharan Air
 Layer moves into the area Sunday, lowering rain chances to end
 the weekend. A wave of deeper tropical moisture then increases
 rain chances into early next week.

It`s another steamy, sunny morning across East Central Florida.
Temperatures and humidity levels continue to run above normal. By
afternoon, widespread heat indices of 103-107F are forecast with
some spots topping out at 108-109F particularly beneath the sea
breeze along the coast.

Although it`s quiet out there, we are quickly destabilizing as it
heats up. PW (total moisture) values are still in the 1.8 to 2.1
inch range, and H5 T`s are a bit on the cool side (-7C). Plentiful
CAPE is forecast, and with the ridge axis nearly atop Central
Florida, light SSW flow just off the deck (across the northern 1/2
of the area) will likely favor a sea breeze collision somewhere
along I-4 late this afternoon into early evening.

From midday into the mid-afternoon, spotty storms are forecast to
develop along the I-95 corridor before the focus shifts inland and
toward I-4 by early evening. Outflows may push some of the
activity back toward the coast north of Cape Canaveral before the
storms diminish mid/late evening.

A reasonable worst-case scenario, or 10% chance of occurrence,
from today`s storms:
-Gusty winds to 40-50 mph
-Rainfall exceeding 3" in 60-90 minutes leading to minor flooding
-Hail to dime size

&&

.PREVIOUS DISCUSSION...
Issued at 420 AM EDT Sat Jul 20 2024

Today-Sunday...Atlantic ridge axis across central FL today lifts
slowly northward into Sunday. Deep moisture, with PW values 2-2.3"
will remain across the area today, which will again keep rain
chances elevated. A few showers or isolated storms may still be
able to brush along the Martin/St. Lucie county coast through
early this morning as this activity lifts slowly northward.
Scattered to numerous showers and storms are then forecast into
the afternoon and evening. Initial storm development is expected
along the east coast sea breeze into early afternoon, with
greatest coverage occurring across to northwest of the I-4
corridor where sea breeze and storm outflow boundary collisions
occur later in the day. Have PoPs ranging from 50 percent along
the immediate coast of southern Brevard County and the Treasure
Coast, increasing up to 70-80 percent near to north of I-4.

Similar to yesterday, a few stronger storms will again be possible.
Some pockets of drier air aloft and relatively cool 500mb temps
around -7C, may allow any stronger convection to produce frequent
lightning strikes, gusty winds of 40-45 mph and small hail. Slow
storm motion toward the N/NE may also lead to locally heavy rainfall
to 2-4", which could lead to minor flooding of urban or poor
drainage areas. Convection will gradually diminish through late
evening, with rain chances generally ending by midnight. However, a
slight chance for onshore moving showers or storms will continue to
be possible along the Treasure Coast tonight.

Some drier and dusty air associated with the Saharan Air Layer
begins to move into south Florida today and then northward across
central Florida into tomorrow. PW values lower to 1.7-1.9" across
much of the area. This drier airmass, as well as southeast flow that
will lead to a faster inland movement of the east coast sea breeze,
should lead to lower shower/storm coverage into tomorrow. Rain
chances lower to 40 percent across much of the area, except 50-60
percent near to north of I-4 where greatest moisture and greatest
potential for late day boundary collisions will reside.

Hot and humid conditions persist through the weekend. Highs will
range from the low to mid 90s each afternoon. Peak heat index values
still look to mostly range from around 103-107F each afternoon.
Can`t rule out some spots, especially along the coast that can see
slightly higher values briefly to 108-109F each day. However,
confidence not high enough to issue a Heat Advisory at this time,
especially with a forecast for higher storm coverage today that
should bring some relief into the afternoon, and drier air into
Sunday that may lower dewpoints a tad. Warm and muggy conditions
continue during the overnight hours, with lows in the mid to upper
70s.

Monday-Tuesday...A wave of deeper tropical moisture, with PW values
2+ inches will move northwest and across the area early this week.
This will increase shower and storm chances Monday and Tuesday, with
PoPs still ranging around 60-70 percent each day. Greatest shower
and storm coverage will continue to be during the afternoon and
evening hours. However, isolated to scattered onshore moving showers
and storms will be possible into the overnight and morning hours,
especially south of the Cape into late Sunday night/early Monday.
Increased convection and cloud cover will limit highs to the low 90s
for much of the area both days, but may still see some mid 90s near
to northwest of I-4 on Monday. With the added moisture and humidity
peak heat index values will still reach around 102-107F each
afternoon before showers and storms increase across the area.

Wednesday-Friday...Deeper moisture shifts northwest of east central
FL into mid to late week, with PW values lowering to around 1.7-
1.8". The Atlantic high pressure ridge axis also lifts farther north
of the area, leading to a predominant and strengthening onshore
flow. This will focus greater rain chances inland and toward the
western side of the FL peninsula. Rain chances lower to 50 percent
along the coast and 60 percent across the interior each day. Highs
will range from the low 90s along the coast and low to mid 90s
inland, with peak heat index values still ranging from 102-107F each
afternoon.

&&

.AVIATION...
(12Z TAFs)
Issued at 718 AM EDT Sat Jul 20 2024

IMPACT:
- Increasing confidence in numerous storms (70-80%) around
  Greater Orlando terminals from 20/21Z-21/01Z. IFR VIS
  restrictions, erratic gusty winds to 30-40 KT, and frequent
  lightning beneath the strongest storms.

High coverage of showers and storms forecast this afternoon,
especially along & northwest of the I-4 corridor. Convection is
expected to begin along the Space and Treasure Coasts around
17-18Z, then spreading inland through 20-21Z. TEMPOs have been
included for all sites for brief CIG/VIS reductions. Southerly
winds this morning will back southeasterly behind the sea breeze
in the afternoon hours. Convection will diminish along the coast
first, then inland by 0-2Z. Winds becoming light overnight. VFR
conditions prevailing outside of convection.

&&

.MARINE...
Issued at 420 AM EDT Sat Jul 20 2024

Today-Sunday...Atlantic ridge axis across the waters will lift
slightly northward into tomorrow, with boating conditions remaining
overall favorable. Lighter south to southeast winds 5-10 knots in
the morning will increase out of the southeast to 10-15 knots each
afternoon as sea breeze moves inland. S/SE winds will then diminish
to 5-10 knots each night. Seas 2-3 feet. Isolated to scattered
showers and storms will continue to be possible over the waters,
especially during the overnight and morning hours.

Monday-Wednesday...Atlantic ridge axis will remain near to just
north of the waters into early to mid week. Winds remain out of the
S/SE, increasing to 10-15 knots each afternoon/evening as the sea
breeze forms and moves inland. Seas will continue to range around 2-
3 feet, but may reach up to 4 feet well offshore, near to north of
the Cape at times.

An increase in showers and storms expected across the waters early
next week as a wave of deeper moisture moves into the region. Storm
coverage will then decrease into mid week as drier air builds in
from the east. Any storms that develop will be capable of producing
cloud-to-water lightning strikes, gusty winds, and heavy downpours.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  93  75  93  76 /  60  50  50  20
MCO  96  76  95  77 /  80  60  40  20
MLB  92  77  91  78 /  50  30  40  20
VRB  92  76  93  77 /  50  20  40  20
LEE  94  77  95  77 /  80  50  60  20
SFB  94  76  95  77 /  80  60  50  20
ORL  95  77  95  77 /  80  60  50  20
FPR  92  76  92  77 /  50  20  40  20

&&

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

$$

UPDATE...Heil
AVIATION...Leahy