Alert archive / Florida / Areal Flood Advisories in 2021

Areal Flood Advisory 100, NWS Melbourne, FL

December 20, 2021Brevard County, Florida

NWS Melbourne, FL issued this areal flood advisory at Dec 20, 2021, 3:10 PM EST for Brevard County, Florida. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Dec 20, 2021, 3:10 PM EST (20:10 UTC)
Expired
Dec 20, 2021, 6:45 PM EST
In force
4 hr
Issued by
NWS Melbourne, FL
Area
Storm-based polygon

County Brevard County, FL

The radar

The Melbourne radar (KMLB), 21 km from the middle of the area, began a volume at 20:13 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Cape Canaveral, FL (KXMR), launched 12:00Z, 8.2 hours before the alert went out and 27 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Cape Canaveral, FL at 12:00Z on 2021-12-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cape Canaveral, FL at 12:00Z on 2021-12-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1 J/kg
Mixed-layer CIN
-68 J/kg
Mixed-layer LCL
736 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Melbourne, FL wrote its last area forecast discussion before this areal flood advisory went out at Dec 20, 10:05 AM EST, 5 hours 5 minutes earlier.

Area forecast discussion, Dec 20, 10:05 AM EST, 5 hours 5 minutes before
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Hazardous weather outlook, Dec 20, 10:26 AM EST, 4 hours 44 minutes before
Hazardous Weather Outlook...UPDATED
National Weather Service Melbourne FL
1026 AM EST Mon Dec 20 2021

AMZ550-552-555-570-572-575-FLZ041-044>047-053-054-058-059-064-141-
144-147-210000-
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-
1026 AM EST Mon Dec 20 2021

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...TODAY AND TONIGHT.

.THUNDERSTORM IMPACT...
Isolated lightning storms will be possible across the area this
afternoon through the night. Any storm that forms will be capable
of lightning strikes, brief heavy downpours, and wind gusts up to
40mph.

.FLOOD IMPACT...
Locally heavy rainfall will be possible across coastal Volusia,
Brevard, and Indian River this afternoon into the overnight
hours. Training or slow moving showers and storms could lead to
minor to localized moderate flooding, especially in low lying and
poor drainage areas. A Flood Watch is now in effect for these
three counties.

.RIP CURRENT IMPACT...
Breezy onshore winds will generate rough surf conditions at
beaches north of Sebastian Inlet today. In addition, there will be
a moderate risk of rip currents area-wide. Always swim near a
lifeguard and never swim alone.

.MARINE THUNDERSTORM GUST IMPACT...
Isolated lightning storms will be possible over the Atlantic
waters and inland lakes through tonight. Any storm that forms
will be capable of lightning strikes and wind gusts up to around
34 kts.

.WIND AND SEA IMPACT...
Hazardous boating conditions developing today, with Small Craft
Advisories going into effect for much of the area from north to
south into the afternoon. Winds up to 20 to 25 knots and seas up
to 7 to 8 feet will be possible. Seas increasing to up to 6 feet
by tonight across the nearshore Treasure Coast waters.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.
High coverage of showers will continue through Tuesday, with
isolated thunderstorms. A few strong storms may develop on
Tuesday, with locally heavy rainfall, gusty winds, and small hail
possible.

At least a moderate risk of rip currents will continue into mid-
week. Hazardous boating conditions also look to continue through
portions of the Atlantic waters through Wednesday.

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

Negron/Leahy

The office that day

Everything else NWS Melbourne, FL issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 20, 3:53 AM ESTBeach Hazards StatementMLBVolusia15 hr
Dec 20, 9:21 AM ESTFlood WatchMLBVolusia19 hr
Dec 20, 4:32 PM ESTAreal Flood AdvisoryMLBBrevard88 min

Nearby

Areal Flood Advisories in Florida, 2021Every areal flood advisory in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.