Area Forecast Discussion
Issued by NWS Melbourne, FL

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FXUS62 KMLB 220922
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
522 AM EDT Fri Mar 22 2024

.DISCUSSION...

...Periods of Showers and Possibly Lightning Storms Through the Day
and Night...
...Stronger Storms Can`t Be Ruled Out to the South Late Tonight...

Currently...First round of today`s showers has moved into east
central Florida, producing light to moderate showers, but so far no
lightning strikes in the area. Leesburg and surrounding areas have
already received a quarter inch of rainfall.  This activity will
continue to push eastward through the morning to start a fairly
rainy period.

Today-Tonight...The southern stream of the jet starts to amplify,
developing a trough that digs down right over Florida, which will
help deepen a mid-level shortwave swinging across the Deep South and
Gulf of Mexico. The center of the surface low developing in response
to the mid-level shortwave tracks along the northern Gulf coast,
then cuts northeast across southern GA towards the Mid Atlantic
seaboard late tonight. Large scale ascent from the upper level
trough will support a weakly forced broad warm sector where rounds
of scattered to numerous showers, the first of which has already
reached ECFL, will continue to develop as the system tracks east.
Pretty good agreement from CAMs this first round will push
offshore or dissipate by the late morning, followed by a break in
the afternoon, but after that solutions quickly diverge due to the
broad weak forcing. As such, was obliged to go with 50-60 pct
PoPs across the area through the afternoon, evening, and
overnight, given the uncertainty. That said, still a pretty good
signal for slightly higher rain chances south, so generally kept
60 pct PoPs south of a line from Lake Kissimmee to Melbourne, with
50 pct PoPs to the north.

Global models continue to advertise shallow lapse rates (around 5
C/km or less this morning), and even some capping due to shortwave
ridges between 700mb and 500mb, resulting in virtually no CAPE
through around 4 AM. CAMs are a little more optimistic, developing
around 500 J/kg MUCAPE by the afternoon. With 500mb temperatures
around -12 C, the environment is supportive of occasional cloud to
ground lightning, as indicated by one cloud to ground strike in
Citrus county so far this morning, so will keep a slight chance
of thunder in the forecast. As alluded to earlier, one area to
keep an eye on will be the southern half of the area late tonight
towards Saturday morning as the environment starts to become more
favorable for deep convection, and perhaps some stronger storms.
GFS shows the cap weaken and lapse rates steepen (more so in the
mid-upper levels than lower levels) as the mid-level trough swings
down into the eastern Gulf, increasing MUCAPE to around 1,000
J/kg or so. Model soundings show a veered wind profile prior to 10
AM as surface winds switch from southerly to southwesterly, modest
low level shear at 15- 20 kts, and substantial bulk shear
(sfc-6km/8km) upwards of 70 kts. That said, development of
stronger storms in the early morning period looks to remain
dependent on evolution of earlier convection, the cap weakening,
and lower level lapse rates steepening enough to allow deeper
convection. CAMs vary between just isolated showers and storms
during the period, to one solution showing an MCS from the Gulf
pushing through central FL. Will continue to monitor.

As for the rest of the forecast, southerly winds become breezy (15-
20 mph) and gusty (up to 30 mph) in the late morning and early
afternoon across most of the area, then back off a little in the
evening. Along the barrier islands, and inland a bit south of the
Cape, windy conditions (20-25 mph with gusts up to 35 mph) develop
during this period, then remain breezy through the evening and
overnight. Afternoon highs forecast to reach the M70s, but depending
on timing of rain, wouldn`t be surprised if a few locations only
made it to the L70s. Overnight lows in the L-M60s. The freshening
southeasterly to southerly winds are expected to produce a moderate
northward flowing longshore current at the beaches, as well as rough
surf, and a Moderate risk of dangerous rip currents.

Sat/Sat night...Positively-tilted upper trough in the southern
stream will cross the FL peninsula. In the low levels, a pre-
frontal trough will cross the area early in the day and low level
flow will veer quickly W/SW. It will be breezy with wind gusts up
to 25 mph. Higher rain chances should be ongoing across southern
sections at sunrise so start rain chances from Okeechobee to the
Treasure coast at 40-60 percent. The upper trough will bring
colder and drier air aloft which will lower rain chances heading
into the aftn. However, the drier air will allow solar insolation
and warming sfc temps into the lower 80s while mid level temps
cool to -13C to -15C. Resulting steepening lapse rates and
increasing DCAPE will create a conditional threat for isolated
strong storms. The primary limiting factor will be the increasing
dry air aloft. But if any deep convection can develop, gusty winds
up to 60 mph and hail will be possible. The conditional threat
for isolated strong/marginally severe storms will end by early
eve.

A cold front will push south across the area Sat night bringing
gusty north winds to coastal sections and passing coastal showers
to Volusia/Brevard counties. Min temps in the upper 50s/lower 60s.

Sunday...Combination of deepening low pressure off the mid Atlc
coast and high pressure building south into the area will produce
a breezy/windy day with a surge of north winds gusting 30 to 35
mph along the coast. Considerable low clouds will keep coastal
sections mostly cloudy to overcast with fast-moving light
showers/sprinkles possible. Interior sections will also start
cloudy but partial clearing will occur during the day. Max temps
should hold in the upper 60s along the Volusia and Brevard
immediate coasts with low to mid 70s elsewhere.

Monday-Thursday...Elongated low level high pressure ridge axis
will push east of the area Mon and local wind flow will veer E/NE
Mon then SE Tue-Thu. This will produce dry conditions with a
warming trend. Max temps will reach mid 70s coast and near 80 far
interior Mon then warming into the low/mid 80s Tuesday and
Wednesday. The next cold front will approach mid week but will be
weakening/slowing with time. Both GFS and ECMWF show low pressure
developing along the front over coastal SE US which swings the
front through Thu. have drawn 20-30% chances for showers and
isolated storms beginning Wednesday afternoon. Thursday has
trended slightly cooler with the front.

The coolest morning will be Monday with mid to upper 50s inland
and lower 60s coast. Generally low to mid 60s are then expected
Tuesday thru Thursday mornings.

&&

.MARINE...
Issued at 249 AM EDT Fri Mar 22 2024

Today-Tonight...Boating conditions continue to deteriorate as a low
pressure system tracks from the north central Gulf coast today
across the Deep South towards the Mid Atlantic seaboard by Saturday.
Small Craft Advisories for all central Florida Atlantic waters go
into effect at 8 AM as SE-S winds increase to 20-25 kts, and a Gale
Warning has been issued for the offshore waters from 2 PM through 4
AM as wind further increase to 25-30 kts with frequent gusts to Gale
force. Winds ease a little late tonight as they start to veer SSW-
SW, becoming 15-20 kts nearshore and 20-25 kts offshore by early
Saturday morning. The SCA for the nearshore waters expires at 4 AM,
but small craft should continue to exercise caution, and the SCA for
the offshore waters remain in effect into Saturday. Seas very
quickly build from 3-4 ft early this morning to 5-7 ft in the
afternoon, and up to 7-9 ft in the Gulf Stream late tonight. The
slight offshore wind component keeps seas near the coast to 4-5 ft.
Scattered to numerous showers and isolated thunderstorms. Stronger
storms capable of wind gusts over 35 kts will be possible,
especially over the Gulf Stream.

Sat-Tue...Low pressure tracks E/NE offshore the Carolina coast
Sat with a quick veering of winds out of the W/SW. Pressure
gradient will weaken allowing winds to drop below 20 knots
offshore with 10-15 knots nearshore. Seas will temporarily fall
below 7 feet offshore Sat aftn. Then a trailing cold front will
cross the waters early Sun with a surge of North winds 20-25
knots. Seas will build rapidly to 10-11 ft in the Gulf Stream and
6-8 ft nearshore so a Small Craft Advisory will need to be
reintroduced. Elongated high pressure ridge axis will shift east
of the waters Monday with winds veering E then SE on Tue. Pressure
gradient will support wind speeds around 15 knots but seas will
be slow to subside due to a moderate to large NE swell, holding
7-8 ft offshore thru Tue. These incoming swells will produce
hazardous conditions near inlets early next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 249 AM EDT Fri Mar 22 2024

Multiple rounds of SHRA/TSRA impacts expected at all ECFL terminals
through the TAF period as a low pressure system approaches Florida.
TEMPOs for MVFR-IFR VIS and MVFR CIGs with first round carried at
all terminals through around 13Z. Confidence in timing then
decreases, so TAFs continue VCSH/VCTS through the forecast, and
being judicious with adding TEMPOs further out than 6 hours. Winds
SE-SSE increase to 10-15 kts this morning, and further increase to
15-20 kts with frequent gusts to around 25 kts in the late morning,
while veering to SSE-S. Winds then ease overnight to around 10 kts
inland and 10-15 kts along the coast as SHRA/TSRA chances remain.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  74  63  80  58 /  60  50  30  20
MCO  74  65  80  60 /  60  50  30  10
MLB  75  65  81  60 /  70  60  30  10
VRB  76  65  82  58 /  70  60  40  10
LEE  73  63  79  57 /  60  50  30   0
SFB  74  64  81  58 /  60  50  30  10
ORL  74  65  80  60 /  60  50  30  10
FPR  75  65  81  58 /  70  60  50  10

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 8 AM this morning to 5 AM EDT Saturday
     for AMZ550-552-555.

     Small Craft Advisory from 8 AM this morning to 2 PM EDT this
     afternoon for AMZ570-572-575.

     Small Craft Advisory from 5 AM to 4 PM EDT Saturday for AMZ570-
     572-575.

     Gale Warning from 2 PM this afternoon to 5 AM EDT Saturday for
     AMZ570-572-575.

&&

$$

SHORT TERM...Haley
LONG TERM....Kelly
AVIATION...Haley


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