Alert archive / Florida / Special Weather Statements in 2011

Special Weather Statement, NWS Melbourne, FL

August 20, 2011Saint Lucie County, Florida

NWS Melbourne, FL issued this special weather statement at Aug 20, 2011, 2:33 PM EDT for Saint Lucie County, Florida. It was in force for 42 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 20, 2011, 2:33 PM EDT (18:33 UTC)
Expired
Aug 20, 2011, 3:15 PM EDT
In force
42 min
Issued by
NWS Melbourne, FL

County Saint Lucie County, FL

The radar

The Melbourne radar (KMLB), 83 km from the middle of the area, began a volume at 18:33 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, 6.6 hours before the alert went out and 122 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 2011-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 719 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 2011-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 square meters per square second.1939Sfc1 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
719 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
945 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
28 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

843 
WWUS82 KMLB 201833
SPSMLB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
233 PM EDT SAT AUG 20 2011

FLZ059-201915-
ST. LUCIE-
233 PM EDT SAT AUG 20 2011

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR STRONG WIND GUSTS
BETWEEN 45 AND 55 MPH OVER ST. LUCIE COUNTY...

* UNTIL 315 PM EDT.

AT 228 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STORM CAPABLE OF PRODUCING STRONG WIND GUSTS OVER SAINT LUCIE WEST...
MOVING NORTHWEST AT 15 MPH.

THE PRIMARY THREAT WILL BE FREQUENT CLOUD TO GROUND LIGHTNING 
STRIKES AND GUSTY WINDS OF 45 TO 55 MPH...WHICH CAN CAUSE UNSECURED 
OBJECTS TO BLOW AROUND...SNAP TREE LIMBS OR CAUSE POWER OUTAGES. 
HEAVY RAINFALL WILL TEMPORARILY REDUCE VISIBILITY. SEEK SHELTER 
INDOORS UNTIL THE STORM PASSES. TORRENTIAL RAINS ARE ALSO ASSOCIATED 
WITH THESE STORMS AND CAN RESULT IN LOCAL PONDING OF WATER ON 
ROADWAYS IN A SHORT AMOUNT OF TIME.

LAT...LON 2743 8067 2755 8056 2724 8030 2722 8049
TIME...MOT...LOC 1832Z 149DEG 11KT 2735 8047

$$

SEDLOCK

What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 20, 9:17 AM EDT, 5 hours 16 minutes earlier.

Area forecast discussion, Aug 20, 9:17 AM EDT, 5 hours 16 minutes before
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
917 AM EDT SAT AUG 20 2011

.DISCUSSION...
ANTICIPATING AN EARLY START TO SOME COASTAL SHOWERS ONCE THE EAST
COAST BREEZE BOUNDARY BEGINS TO DEVELOP LATE THIS MORNING. STRONG SB
HEATING COMBINED WITH PWAT JUST OVER 2 INCHES AND SLY ENVIRONMENTAL
FLOW WILL LEAD TO THE DEVELOPMENT OF DEEP CONVECTION WITH THREAT OF
LOCALLY HEAVY RAINS AND FREQUENT LIGHTNING. LIGHT SLY STEERING LEVEL
WINDS WILL NUDGE STORMS SLOWLY NORTHWARD AND ACTIVITY WILL STEADILY
TRANSITION WEST OF I95 INLAND DURING THE COURSE OF THE AFTERNOON
WHERE AN EVENTUAL LARGE SCALE BOUNDARY MERGER OVER THE INTERIOR
COUNTIES ALONG WITH OUTFLOW INTERACTIONS WILL INCREASE LIKELIHOOD OF
NUISANCE FLOODING AND THE POSSIBILITY OF STRONGER STORMS CONTAINING
FREQUENT TO EXCESSIVE LIGHTNING AFTER AROUND 3 PM FROM THE THEME
PARKS TO ORLANDO AND  SANFORD. WITH MORE FAVORABLE PARAMETERS FOR
DEEP CONVECTION IN PLACE WL SLIGHTLY INCREASE POPS OVER THE SOUTH
AND INTERIOR WITH LOCALLY HEAVY RAIN WORDING INLAND AS WELL ON FCST
UPDATE.

&&

.AVIATION...
SEA BREEZE SHOWERS/STORMS SHOULD DEVELOP NEAR THE COAST ALONG ECSB
BOUNDARY AROUND 15-17Z. ACTIVITY WILL PROPAGATE INLAND WITH INTERIOR
TERMINALS HAVING A CHANCE FOR STORMS ABOUT 20-24Z.

&&

.MARINE...
TODAY/TONIGHT...(PREVIOUS) ATLANTIC RIDGE AXIS IS TRANSITIONING
NORTH WHICH WILL CAUSE WINDS TO GRADUALLY BACK FROM THE SOUTH TO THE
SOUTHEAST.  SPEEDS SHOULD BE 10 KNOTS OR LESS EXCEPT FOR A DIURNAL
EVENING INCREASE TO 10-15 KNOTS.  MOISTURE WILL BE HIGH TODAY SO
EXPECT A CHANCE OF SHOWERS/STORMS...ESPECIALLY THIS MORNING.  MODELS
SHOW SLIGHTLY DRIER AIR FILTERING IN FROM THE SOUTHEAST TONIGHT.

&&

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

&&

PUBLIC/MARINE/AVIATION...JP
RADAR/IMPACT WEATHER...TES/JG
Hazardous weather outlook, Aug 20, 11:30 AM EDT, 3 hours 3 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MELBOURNE FL
1130 AM EDT SAT AUG 20 2011

AMZ550-552-555-570-572-575-FLZ041-044>047-053-054-058-059-064-141-
144-147-201600-
COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE
OUT 20 NM-
COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN
INLET OUT 20 NM-
COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO
60 NM OFFSHORE-
WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO
60 NM OFFSHORE-
WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-
INLAND VOLUSIA-NORTHERN LAKE-ORANGE-SEMINOLE-SOUTHERN BREVARD-
OSCEOLA-INDIAN RIVER-OKEECHOBEE-ST. LUCIE-MARTIN-COASTAL VOLUSIA-
SOUTHERN LAKE-NORTHERN BREVARD-
1130 AM EDT SAT AUG 20 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

.THUNDERSTORM IMPACT...
A MOIST AIR MASS WILL REMAIN ACROSS THE AREA. SEA BREEZE STORMS ARE
EXPECTED TO DEVELOP THROUGH EARLY AFTERNOON NEAR THE COAST...THEN
INCREASE IN COVERAGE AND INTENSITY BY LATE AFTERNOON ACROSS THE
INTERIOR AS NUMEROUS BOUNDARY INTERACTIONS OCCUR.

THE PRIMARY HAZARD WILL BE LIGHTNING STRIKES...WHICH WILL BE
FREQUENT IN ISOLATED STRONG STORMS.

.FLOOD IMPACT...
RAINFALL AMOUNTS IN ISOLATED...SLOW MOVING STRONG STORMS THIS
AFTERNOON WILL REACH NEAR 3 INCHES AGAIN. THIS WILL PRODUCE WATER
PONDING ON ROADWAYS AND OTHER POORLY DRAINED AREAS.

.MARINE THUNDERSTORM GUST IMPACT...
SCATTERED SHOWERS AND STORMS WILL CONTINUE TO MOVE NORTH AROUND 10
MPH THIS AFTERNOON OVER THE COASTAL WATERS. OCCASIONAL LIGHTNING
STRIKES AND WIND GUSTS TO 25 KNOTS ARE EXPECTED. STORMS OVER THE
MAINLAND WILL MOVE NORTH AT 5 TO 10 MPH AND FAVOR COASTAL COUNTIES
EARLY THIS AFTERNOON AND INTERIOR COUNTIES LATER IN THE DAY.
ISOLATED STRONG STORMS WITH FREQUENT LIGHTNING STRIKES AND WIND
GUSTS AROUND 30 KNOTS ARE POSSIBLE ACROSS THE INTERIOR.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
A SOUTHEAST TO EAST WIND FLOW INTO THE MIDDLE OF NEXT WEEK WILL
FAVOR INTERIOR AREAS FOR AFTERNOON THUNDERSTORMS. AN INCREASING
EASTERLY SWELL WEDNESDAY INTO THURSDAY NEXT WEEK WILL HEIGHTEN THE
RIP CURRENT RISK.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY.

SEDLOCK/LASCODY

In the hours before

Special weather statement, Aug 20, 2:33 PM EDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
233 PM EDT SAT AUG 20 2011

FLZ059-201915-
ST. LUCIE-
233 PM EDT SAT AUG 20 2011

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR STRONG WIND GUSTS
BETWEEN 45 AND 55 MPH OVER ST. LUCIE COUNTY...

* UNTIL 315 PM EDT.

AT 228 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STORM CAPABLE OF PRODUCING STRONG WIND GUSTS OVER SAINT LUCIE WEST...
MOVING NORTHWEST AT 15 MPH.

THE PRIMARY THREAT WILL BE FREQUENT CLOUD TO GROUND LIGHTNING
STRIKES AND GUSTY WINDS OF 45 TO 55 MPH...WHICH CAN CAUSE UNSECURED
OBJECTS TO BLOW AROUND...SNAP TREE LIMBS OR CAUSE POWER OUTAGES.
HEAVY RAINFALL WILL TEMPORARILY REDUCE VISIBILITY. SEEK SHELTER
INDOORS UNTIL THE STORM PASSES. TORRENTIAL RAINS ARE ALSO ASSOCIATED
WITH THESE STORMS AND CAN RESULT IN LOCAL PONDING OF WATER ON
ROADWAYS IN A SHORT AMOUNT OF TIME.

LAT...LON 2743 8067 2755 8056 2724 8030 2722 8049
TIME...MOT...LOC 1832Z 149DEG 11KT 2735 8047

SEDLOCK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 3:36 PM EDTSpecial Weather StatementMLBLake, Orange, Osceola39 min

Nearby

Special Weather Statements in Florida, 2011Every special weather statement in 2011

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.