606
FXUS62 KMLB 210133
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
933 PM EDT Thu Jun 20 2024

...New UPDATE...

.UPDATE... (Through Friday)
Issued at 933 PM EDT Thu Jun 20 2024

KEY MESSAGES...

- Low pressure 200 miles east of Cape Canaveral has a 50% chance
  of tropical development over the next 18 hours as it approaches
  North Florida.

- Scattered to numerous showers and isolated lightning storms
  overnight north of Melbourne to Kissimmee. Shower coverage on
  Friday is expected to be highest north of Orlando.

- Hazardous beach and boating conditions continue tonight, with
  large waves and a high risk of deadly rip currents.

- Increasing heat and humidity near and south of Orlando on
  Friday, with max heat index readings as high as 100-105F.


Invest 92L, a weak low pressure system, is approaching Florida`s
Atlantic coast tonight. A surge of deep moisture is moving onshore
now from Melbourne northward, with PW`s sharply increasing to
around 2.50" according to MIMIC-TPW data. This is above the max
moving average, and approaching record daily values for late June.
Bands of showers are increasing just off the coast. Through the
overnight, shower chances increase to around 30% along the
Treasure Coast, 40-50% for Melbourne to Orlando, and 60-80% from
Titusville to Daytona Beach. Mainly north of Melbourne, there is a
20-40% chance of receiving more than an inch of rain through mid-
morning Friday, and a lower (approximately 10%) chance of spotty
2 inch amounts where repeated rains occur.

As the low approaches northeast Florida, we will begin to reside
under a surface trough, allowing the pressure gradient to relax
overnight into Friday morning. Expect winds to become lighter and
more variable. The exception to this will be in the vicinity of
heavier showers and any isolated storms, especially along the
coast, where gusts to 25-35 mph will be attainable.

Breaking 5-7 FT surf and a high risk of rip currents continue at
our area beaches overnight.

Friday`s forecast is somewhat challenging as the steering flow
begins to collapse around 92L. The plume of deep moisture will
slowly move northwestward, and modestly drier air will reside
immediately to its south. Guidance still disagrees on how quickly
this plume exits our area. At this time, showers appear likely
(55-65%) north of Orlando in the morning, becoming more scattered
(30-50%) near Orlando and isolated to dry (<20%) south from there.
Then, we will reintroduce a 30% chance of storms for much of the
area late in the afternoon as some moisture tries to sneak back in
from the south.

While sunshine will break out for our southern communities,
clouds may linger along and north of I-4. Highs on Friday will be
dependent on the clearing trend from south to north. High
confidence in low/mid 90s over South-Central Florida
(Osceola/Okeechobee) and the interior Treasure Coast, and upper
80s/low 90s Space and Treasure Coasts. Along and north of I-4
where clouds may linger, went with a range from 85-92F, "coolest"
near Daytona Beach. With the high humidity, peak heat index
readings from 95-105F are expected, highest south of Orlando.

&&

.PREVIOUS DISCUSSION... (Saturday - Wednesday)
Issued at 300 PM EDT Thu Jun 20 2024

Saturday-Wednesday...Saturday marks the beginning of increasing
rain chances this weekend and into next week. Upper level ridging
stays in place across the southern tier of the U.S., weakly
influencing the overall pattern here in Florida. H500 falls across
the southeast and Mid Atlantic are expected Sunday into Monday as
a low pressure system moves across the Great Lakes region.
Surface flow will remain southerly, backing southeast during the
afternoon as the sea breeze forms. Light flow becomes increasingly
SSW through midweek next week. With PW around 2"+ through much of
this period, expect at least scattered to perhaps numerous
showers and storms each afternoon and evening as sea breeze and
storm- scale boundary collisions occur over the peninsula. PoPs go
from 50-55 percent Saturday up to 60-70 percent later in the
weekend and next week. The NBM remains a bit aggressive so
forecast values still remain under that and some of the other
medium range guidance. Regardless, this stretch of days could
provide some additional, much needed rain for parts of the area.
Temperatures through the extended stay warm, generally in the low
90s, with heat indices approaching 100-107. Nighttime temperatures
will stay in the mid to upper 70s.

&&

.AVIATION...
(00Z TAFs)
Issued at 725 PM EDT Thu Jun 20 2024

IMPACT:
- Increasing shower chances overnight (40-70%) with low (20%)
  chance of storms for DAB/SFB/TIX/MCO/LEE, along with
  occasionally reduced CIGs (MVFR).

A rather complicated forecast over the next 12-24 HR. Low
pressure arriving from the Atlantic overnight will bring periods
of showers to areas near and north of ISM/MCO/MLB. CIGs may go
into prevailing MVFR between 08-12Z over some of these areas
(20-40% probability) with only a 10% chance of reaching IFR. Winds
should actually lessen overnight into Friday morning, becoming
variable as the disturbance moves nearby. Exception to this is the
potential for brief gusts to 25 KT in heavier showers. Showers
will be less frequent for the Treasure Coast terminals overnight.
On Friday, showers gradually diminish over our Greater
Orlando/Daytona terminals by late morning/afternoon as winds try
to turn from SSE to SE 5-15 KT.

&&

.MARINE...
Issued at 300 PM EDT Thu Jun 20 2024

Tonight...Hazardous marine conditions remain with a Small Craft
Advisory in effect. Breezy to gusty northeast winds persist as an
approaching low pressure system brings rain and isolated lightning
storms through Friday morning. Seas build up to 9 feet offshore,
mainly north of Sebastian Inlet. Closer to the coast seas 5-7 ft
are expected. Winds begin to subside from midnight onward as the
Atlantic disturbance (AL92) begins to lift northwestward.

Friday-Monday (modified previous)...By Friday morning, winds are
forecast to be southeasterly. Seas subside through the day,
becoming 4-6 ft by the afternoon. Scattered showers with a few
embedded lightning storms are forecast through at least Friday
morning, especially near and north of Cape Canaveral.

Improving boating conditions this weekend into early next week,
with southeasterly to southerly winds remaining under 15 kts.
Seas 3-4 ft becoming 2-3 ft through the period. However, greater
daily shower and thunderstorm coverage is expected, especially
early next week, with increasing chances for offshore-moving
convection each afternoon and evening.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  75  87  77  90 /  70  70  30  50
MCO  75  91  77  92 /  50  50  20  60
MLB  75  89  78  90 /  40  30  20  50
VRB  74  88  77  90 /  30  30  30  50
LEE  76  90  78  94 /  50  60  20  60
SFB  75  90  77  93 /  50  50  20  60
ORL  75  91  77  93 /  50  50  20  60
FPR  73  89  76  90 /  30  30  30  50

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...High Surf Advisory until 4 AM EDT Friday for FLZ141-154-159-164-
     347-447-647-747.

AM...Small Craft Advisory until 4 AM EDT Friday for AMZ550-552-555-
     575.

     Small Craft Advisory until 11 AM EDT Friday for AMZ570-572.

&&

$$

UPDATE...Heil
AVIATION...Heil