Small Craft Advisory 39, NWS Melbourne, FL

057 
WHUS72 KMLB 150741
MWWMLB

URGENT - MARINE WEATHER MESSAGE
National Weather Service Melbourne FL
341 AM EDT Sun Oct 15 2023

AMZ570-572-151200-
/O.EXT.KMLB.SC.Y.0039.000000T0000Z-231015T1200Z/
Flagler Beach to Volusia-Brevard County Line 20-60 nm-Volusia-
Brevard County Line to Sebastian Inlet 20-60 nm-
341 AM EDT Sun Oct 15 2023

...SMALL CRAFT ADVISORY NOW IN EFFECT UNTIL 8 AM EDT THIS
MORNING...

* WHAT...Winds near 20 kt with gusts up to 30 kt.

* WHERE...Flagler Beach to Volusia-Brevard County Line 20-60 nm 
  and Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.

* WHEN...Until 8 AM EDT this morning.

* IMPACTS...Conditions will be hazardous to small craft.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Inexperienced mariners, especially those operating smaller
vessels, should avoid navigating in hazardous conditions.

&&

$$

East Central Florida Forecast Discussion
National Weather Service Melbourne FL
945 AM EDT Sat Oct 14 2023

.DISCUSSION...
Currently...Slowly veering winds accompany arrival of a drier
airnmass to the region today. Sct-bkn lower clouds will continue to
progress across the I-4 corridor southward through the morning. With
the locak of radar returns and expectations of the drier airmass
outracing effects from aftn heating, PoPs were further reducedacross
the south along with eliminating a chc of any storm development
across ECFL the remainder of the day. The morning sounding at XMR
showed a significant mid level cap of -1.5C @H5 along with drying
since Friday. The local forecast has been updated earlier.

from prev disc...

Today-Tonight...A weak area of low pressure will move NE up the
southeast U.S. coast today. As this low pulls farther away from the
region, deep W/NW flow will usher in drier air into the area and
finally begin to bring some relief from the humid conditions that
have been in place over the past few days. PW values will be highest
across Okeechobee and the Treasure Coast today (up to 2.0 inches).
This will lead to a little greater cloud cover over this region,
with isolated showers possible well south.

North of Okeechobee County and the Treasure Coast, rain chances
remain out of the forecast, with skies gradually clearing into the
afternoon where any lower cloud cover can build in this morning.
This will lend to better viewing conditions for the solar eclipse
today (partial for east central FL, between 50-60% obscuration),
which will begin late morning, peak during early afternoon, and
end by 3 PM.

It will still be warm today, with highs in the mid to upper 80s,
with some values around 90 degrees possible. Cold front moving
southward through the region will continue to usher in drier air and
cooler conditions tonight, with temperatures falling into the mid to
upper 60s overnight.

Sunday-Tuesday night...A dramatic pattern change will sweep in
significantly cooler temperatures and lower humidity to begin this
week. The 13/12Z grand ensemble and its clusters are in strong
agreement on the upper-air setup across North America, which will
be quite amplified. A trough will deepen on the East Coast, with
enhanced meridional (northerly) flow on its western flank as
positive height anomalies bridge from the Four Corners to Nunavut
Province, Canada. This will force a couple of dry frontal
boundaries quickly southward through the entire Florida Peninsula
early in the period, each of them delivering a batch of modified
cP air to the subtropics. H5 heights will bottom out around 570 to
576 dam by Monday night, which is 3+ standard deviations below
normal for mid-October. H85 temperatures will fall from ~ +15C
Sunday to +7 to +10C Monday and Tuesday. Most impressively, total
atmospheric moisture values are set to drop from above the max
moving climatological average (> 2.1") as of this morning to below
the min moving average (< 0.75") in just about three days!

RH cross sections leave little doubt that we are in for a stretch of
mostly clear skies, interspersed with only a few cumuli. On Sunday,
highs will range from near 80 north of Orlando to the mid/upper 80s
along the Treasure Coast. Monday and Tuesday will be the coolest
days, with afternoon readings in the low 70s north of I-4 to the mid
70s elsewhere. A handful of record cool high temperatures could be
in jeopardy on Monday/Tuesday!  Breezy west to northwest winds 10-15
mph each day, occasionally gusting 20+ mph Sunday and Monday
afternoons.

Early risers may want to grab a sweatshirt. Morning lows in the mid
50s to low 60s Monday morning drop toward the low/mid 50s Tuesday
morning. On Tuesday and Wednesday mornings, places northwest of a
Deltona - Clermont line have a 10-30% chance of falling into the
upper 40s. By Wednesday morning, coastal communities south of the
Cape may only fall into the low/mid 60s as light onshore winds
develop.

Wednesday-Saturday...Eventually, rain chances will return as
temperatures turn a bit warmer. From a longwave perspective,
ensemble clusters have locked onto rising heights through at least
Friday as the early week trough fills and lifts away from
Florida. Another trough is then set to move from the Plains to the
East Coast from Friday into next weekend. Per typical, confidence
falls off as we move later into the forecast. By Friday night,
ensembles are nearly evenly split on the progression of the trough
axis: 40% of members have a cold front crossing the state Friday
night, while the other 60% hold its passage up until later
Saturday or Sunday. There are also disagreements in the depth of
this trough. Roughly half of the members are showing a closed low
by Saturday evening, centered somewhere over the Deep South.

Wind trajectories will quickly turn onshore Wednesday, allowing
modification to begin. Boundary-layer moisture will increase,
allowing for slight (20%) chances of a few showers at the immediate
coast south of Fort Pierce late Wednesday. By Thursday, the chances
for showers / isolated storms pick up a bit more, 20-40%, for places
east and south of Orlando, highest again Treasure Coast. As the
trough swings closer, southwesterly flow increases on Friday,
dragging a slug of deeper tropical moisture across the peninsula (30-
60% chance of PW values exceeding 1.75"). This necessitates 40-60%
coverage of showers and storms to end the work week. Then, as
mentioned before, disagreements abound on the behavior of the trough
next weekend. For now, we will stick close to or just above
statistical guidance for rain chances on Saturday (30-50%),
considering the good odds that a front will be nearby.

Temperatures will turn warmer late in the week, with upper 70s to
low/mid 80s forecast across the area. Lows will be coolest Thursday
(upper 50s Lake Co. to upper 60s Treasure Coast) before climbing
some Friday and Saturday (generally 60s, except low 70s near the
coast).

&&

.MARINE...
Today-Tonight...Westerly flow will continue over the waters today,
around 10-15 knots. Poor boating conditions then developing into
tonight as winds veer slightly to the W/NW and increase up to 15 to
20 knots offshore overnight as a cold front moves through the area.
Small craft should exercise caution if venturing into the offshore
waters tonight. Seas will range from 3-5 feet.

Isolated showers may still be able to push offshore the Treasure
Coast today. Otherwise drier conditions will occur across the
waters.

Sunday-Wednesday...WNW winds 10-15 KT Sunday will freshen to
10-20 KT (locally 20-25 KT beyond 30 nm) while veering NW on
Monday into Monday night. Winds slacken to 10-15 KT Tuesday,
becoming NE by Wednesday. Poor to hazardous offshore boating
conditions for small craft operators, particularly in the Gulf
Stream on Monday and Tuesday with seas building to 5-8 feet due to
winds opposing the current. Within 20 miles of the coast, seas of
generally 2-4 feet through the period. Breezes will create choppy
conditions for inshore and Intracoastal waters, particularly
early in the week. Scattered rain showers are forecast well
offshore on Monday, and there will be a slight chance for showers
along the Treasure Coast by Wednesday.

&&

.AVIATION...
(12Z TAFS) Issued at 945 AM EDT Sat Oct 14 2023

Lower clouds developing and expanding across portions of the area
through late morning, largely producing MVFR cigs. However, any of
this cloud cover that can work into the area will lift and break up
into the morning, as drier air continues to build in and daytime
heating increases. Some lingering MVFR cigs, as well as a few
showers and a storm or two will continue to be possible mainly
through early afternoon from near KVRB southward today. Winds will
be out of the west, increasing to around 10 knots this afternoon,
and remain slightly elevated around 7-9 knots tonight.

&&

.HYDROLOGY...
Issued at 327 AM EDT Sat Oct 14 2023

The Saint Johns River above Lake Harney remains within Action Stage,
and is forecast to remain steady into early next week. As recent
heavy rainfall drains out of the basin, levels will begin to decline
by mid week.

Recent heavy rainfall over the Saint Johns basin has slowed the
decline in levels at Astor, leading to a slight rise over the past
24 hours. The river at Astor will remain near, or just within
Moderate Flood Stage through early next week.

&&

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

&&

JP/BS

Hazardous Weather Outlook
National Weather Service Melbourne FL
947 AM EDT Sat Oct 14 2023

AMZ550-552-555-570-572-575-FLZ041-044>046-053-058-141-144-154-159-
164-247-254-259-264-347-447-547-647-747-142300-
Flagler Beach to Volusia-Brevard County Line 0-20 nm-Volusia-
Brevard County Line to Sebastian Inlet 0-20 nm-
Sebastian Inlet to Jupiter Inlet 0-20 nm-Flagler Beach to Volusia-
Brevard County Line 20-60 nm-Volusia-
Brevard County Line to Sebastian Inlet 20-60 nm-
Sebastian Inlet to Jupiter Inlet 20-60 nm-Inland Volusia-
Northern Lake-Orange-Seminole-Osceola-Okeechobee-Coastal Volusia-
Southern Lake-Coastal Indian River-Coastal Saint Lucie-
Coastal Martin-Inland Northern Brevard-Inland Indian River-
Inland Saint Lucie-Inland Martin-Mainland Northern Brevard-
Northern Brevard Barrier Islands-Inland Southern Brevard-
Mainland Southern Brevard-Southern Brevard Barrier Islands-
947 AM EDT Sat Oct 14 2023

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

.EXCESSIVE HEAT IMPACT...
The combination of above normal temperatures and humidity will
produce peak heat indices of 100 to 105 across Okeechobee County
and the Treasure Coast this afternoon.

.RIP CURRENT IMPACT...
A Moderate Risk of life-threatening rip currents continues at all
central Florida Atlantic beaches. Always swim near a lifeguard,
and never swim alone.

.WIND AND SEA IMPACT...
Small craft should exercise caution if venturing into the offshore
waters tonight due to west to northwest winds increasing up to 15
to 20 knots.

.RIVER FLOOD IMPACT...
The Saint Johns River above Lake Harney remains within Action Stage,
and is forecast to remain steady into next week. As recent heavy
rainfall drains out of the basin, levels will begin to decline by
mid week.

Recent heavy rainfall over the Saint Johns basin has slowed the
decline in levels at Astor, leading to a slight rise over the past
24 hours. The river at Astor will remain near or at Moderate Flood
Stage through early next week.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
Poor boating conditions on Sunday will become poor to hazardous
into early next week, as west to northwest winds increase across
the waters behind a passing cold front.

At least a Moderate risk of rip currents is expected through the
weekend at all central Florida Atlantic beaches.

.SPOTTER INFORMATION STATEMENT...
Spotter activation will not be needed today and tonight.

Pendergrast