Areal Flood Warning 21, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
957 AM EDT Thu Oct 1 2020

.DISCUSSION...

...Flood Watch Remains in Effect for Coastal Martin and St Lucie
Counties Through Tonight...

Current-Tonight...Some heavy rainfall across the Treasure Coast late
last night and early this morning. This resulted from a likely
combination of a stalled frontal boundary to the south, deep
moisture, coastal convergence, diffluence aloft, and good ol'
fashion shallow, efficient precipitation producing showers and
isolated lightning storms. Many neighborhoods have seen flooding,
especially around Hobe Sound in coastal Martin County. Residents
will need to stay alert as any additional rainfall will immediately
become runoff as these areas remain saturated. Local radar shows
this activity remains fairly persistent with additional convection
over the local waters and near the coast.

Mesoscale models suggest additional convection this afternoon
resulting from the sea breeze boundary, deep moisture, and
additional boundary collisions from previous activity. While some of
this activity may advance into the interior, as far north as Osceola
County, it appears confined closer to the coast from the Cape
southward. With that said, may have to extend current PoP
configuration further north. Northward across ECFL should still
continue to see a pleasant day.

Highs generally in the L-M80s. Lows tonight will range from the L-M
60s for Lake/Volusia southward toward Okeechobee County while the
Space/Treasure coasts realize U60s to L70s.

&&

.AVIATION...Light N/NNE/NE winds today and generally VFR, except the
Treasure Coast which is plagued by higher moisture with SCT
convection periodically around. MVFR conds in/around showers and
ISOLD lightning storms. Will monitor as convective threat, according
to local/short range models, may advance northward toward KMLB and
potentially KTIX. Much of any additional activity today will result
from deep moisture and sea breeze/mesoscale outflow boundaries along
the Space/Treasure coasts from earlier showers/storms.

&&

.MARINE...Today-tonight...The nearly stalled frontal boundary near
the southern waters combined with deep moisture will continue to
initiate scattered showers and isolated storms. Threats include
locally heavy downpours, cloud to water lightning, and gusty winds
to near 30 kts. Activity could spread further northward towards
Melbourne with sea breeze initiation, surface heating, and additional
mesoscale boundary collisions. N/NNE winds generally 10-15 kts,
though convection near the coast and across our southern waters
could promote variable winds at times due to the disruption. Seas
generally 3-4 ft.

&&

.HYDROLOGY...The St Johns river at Astor is forecast to remain near
Moderate Flood Stage for the next couple of days before slowly
declining later this week into Minor Flood Stage. Water levels along
the Middle Saint Johns River Basin are also forecast to remain
elevated the rest of this week at Deland, Sanford and Lake Harney.
Refer to daily Flood Statements from NWS Melbourne for the latest
river levels and forecasts.

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch through late tonight for Martin-St. Lucie.

AM...None.
&&

Sedlock/Leahy

Hazardous Weather Outlook...Updated
National Weather Service Melbourne FL
1119 AM EDT Thu Oct 1 2020

AMZ550-552-555-570-572-575-FLZ041-044>047-053-054-058-059-064-141-
144-147-020000-
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-Southern Brevard-Osceola-
Indian River-Okeechobee-St. Lucie-Martin-Coastal Volusia-
Southern Lake-Northern Brevard-
1119 AM EDT Thu Oct 1 2020

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

.THUNDERSTORM IMPACT...
Isolated lightning storms will be possible today south from
Melbourne through Jupiter Inlet to include the adjacent Atlantic
waters. Cloud to ground lightning strikes, torrential downpours, and
brief gusty winds will be possible. Organized storm motion is
forecast to be slow toward the northeast, however, shallow and heavy
shower activity over the Atlantic and along the Treasure Coast will
propagate toward the west.

.FLOOD IMPACT...
Heavy showers and isolated lightning storms from earlier this
morning have produced rainfall amounts of 4 to 7 inches across
coastal areas of Martin County and 3 to 5 inches in coastal Saint
Lucie County. Additional showers and isolated lightning storms are
expected through tonight and flooding, potentially life-threatening,
will be possible especially in urban, low lying, and already
saturated areas. A Flood Watch remains in effect through tonight for
these areas.

.RIP CURRENT IMPACT...
There will be a Moderate risk for life-threatening rip currents at
area beaches today. While rips will be present all day, the threat
will be highest through 600 PM due to tidal effects. To reduce your
chance of being caught in the seaward pull of a rip current, swim
only within sight of a lifeguard, and never swim alone.

.RIVER FLOOD IMPACT...
The Saint Johns River at Astor has fluctuated in and out of
Moderate Flood Stage in the last 2 days. For today, Astor is
forecast to remain in Minor to Moderate Flood and due to lower
rain chances through the remainder of the week, levels are
forecast to slowly subside. The Saint Johns River near Deland,
Sanford, and above Lake Harney is forecast to remain within Action
Stage through the week.

Refer to daily Flood Statements from NWS Melbourne for the latest
river levels and forecasts.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.
Isolated lightning storms are expected through Friday south of
Vero Beach, with higher rain and lightning storm chances
returning areawide this weekend and into early next week. Locally
heavy rainfall leading to minor flooding issues along area
roadways and poor drainage areas could occur along the Treasure
Coast into the weekend.

.SPOTTER INFORMATION STATEMENT...
Spotters across Saint Lucie and Martin counties should monitor the
weather and self activate if needed. Reports of flooding will be
greatly appreciated.

Sedlock/Negron

PRELIMINARY LOCAL STORM REPORT
National Weather Service Melbourne FL
1148 AM EDT THU OCT 1 2020

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1024 AM     HEAVY RAIN       2 NNW HOBE SOUND        27.10N 80.15W
10/01/2020  E7.00 INCH       Martin             FL   UTILITY COMPANY

            RELAYED REPORT FROM SOUTH MARTIN REGIONAL UTILITY, WHERE
            THEY MEASURES JUST OVER 7 INCHES OF RAINFALL AT THEIR
            PLANT ON SE OSPREY ST. RAINFALL FROM LAST NIGHT AND THIS
            MORNING.

&&

CL