Alert archive / Florida / Special Weather Statements in 2015

Special Weather Statement, NWS Melbourne, FL

April 20, 2015Saint Lucie County, Florida

NWS Melbourne, FL issued this special weather statement at Apr 20, 2015, 12:27 PM EDT for Saint Lucie County, Florida. It was in force for 48 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: Apr 20, 2015, 12:27 PM EDT (16:27 UTC)
Expired: Apr 20, 2015, 1:15 PM EDT
In force: 48 min
Issued by: NWS Melbourne, FL

County Saint Lucie County, FL

The radar

The Melbourne radar (KMLB), 99 km from the middle of the area, began a volume at 16:29 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, 4.5 hours before the alert went out and 140 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 841 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 1041 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.2

Open this sounding in Storm Lab

The text

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

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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 Apr 20, 10:35 AM EDT, 1 hour 52 minutes earlier.

Area forecast discussion, Apr 20, 10:35 AM EDT, 1 hour 52 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
1035 AM EDT MON APR 20 2015

.DISCUSSION...

...STRONG TO ISOLATED SEVERE STORMS POSSIBLE THIS AFTERNOON AND
EVENING...

LATEST RADAR AND LIGHTNING IMAGERY SHOWS SQUALL LINE OVER THE NRN
AND CENTRAL GULF SHIFTING EASTWARD OUT AHEAD OF WEAK FRONT MOVING
INTO THE SOUTHEAST STATES. TRACK ESTIMATES HAS THIS LINE NEARING THE
WEST CENTRAL FL COAST BY EARLY THIS AFT. MID/HIGH LEVEL DEBRIS
CLOUDS FROM THIS CONVECTION ALREADY MOVING ACROSS THE REGION WHICH
WILL LIMIT DAYTIME HEATING TODAY. HOWEVER SHOULD STILL SEE ENOUGH
FILTERED SUNSHINE FOR HIGHS TO REACH THE MID TO UPPER 80S INTO
EARLY/MID AFT. DECENT HEATING...DEEP MOISTURE AND MARGINALLY
FAVORABLE DYNAMIC SUPPORT FROM SUBTROPICAL JET MAY ALLOW THIS LINE
TO MAINTAIN ENOUGH STRENGTH TO HOLD TOGETHER AS IT INITIALLY MOVES
ONSHORE. THE POTENTIAL FOR STRONG TO ISO SEVERE WIND GUSTS WILL
ACCOMPANY THIS CONVECTIVE BAND AS IT MOVES TOWARD LAKE COUNTY AND I-
4 CORRIDOR. STORM PREDICTION CENTER HAS PLACED THIS REGION UNDER A
SLIGHT RISK IN THE LATEST DAY 1 UPDATE. IN ADDITION TO WIND...HAIL
UP TO QUARTER SIZE WILL ALSO BE A CONCERN AS MORNING SOUNDINGS SHOW
COOLER TEMPS ALOFT WITH -10 TO -12C AT 500MB.

IN ADDITION TO THIS LINE...HRRR/WRF MODELS SHOW ADDITIONAL SCT-NMRS
SHOWERS AND STORMS DEVELOPING OUT AHEAD OF THIS SYSTEM AND PUSHING E-
NE ACROSS THE AREA INTO THE AFT HOURS. THESE STORMS COULD ALSO BRING
WITH THEM THREAT FOR STRONG WIND GUSTS AND SMALL HAIL...ESPECIALLY
WITH BOUNDARY INTERACTIONS TOWARD THE COAST IF THE EAST COAST SEA
BREEZE IS ABLE TO FORM. THEREFORE HIGH POPS UP TO 70-80 PERCENT
TODAY STILL LOOK GOOD WITH NO MAJOR CHANGES TO THE FORECAST PLANNED.

&&

.AVIATION...VFR THROUGH THE MORNING. INCREASING COVERAGE OF
SHRA/TSRA INTO THE AFT WITH APPROACHING SQUALL LINE OVER THE GULF
AND ADDITIONAL SCT-NMRS CONVECTION THAT FORMS OUT AHEAD OF THIS LINE
THAT BOTH THE WRF AND HRRR MODELS INDICATE. STRONG TO ISO SEVERE
WIND GUSTS AND HAIL POSSIBLE WITH ANY STORMS TODAY. TEMPO IFR/MVFR
CONDS WILL OCCUR WITH ANY CONVECTION TODAY WITH BEST TIMEFRAME FOR
THIS ACTIVITY BTW 18-00Z.

&&

.MARINE...

TODAY-TONIGHT...(PREVIOUS DISCUSSION) SOUTH TO SOUTHWEST WINDS
AROUND 10 KNOTS NEARSHORE AND 10 TO 15 KNOTS OFFSHORE. SEAS 2 TO 3
FEET NEARSHORE AND 3 TO 4 FEET WELL OFFSHORE. SCATTERED TO NUMEROUS
AFTERNOON WEST TO EAST MOVING SHOWERS AND STORMS. FAST MOVING...20
TO 30 MPH...STORMS AGAIN. BOATERS SHOULD KEEP AN EYE TO THE WEST FOR
FAST APPROACHING STORMS.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  85  67  81  62 /  80  50  20  10
MCO  86  67  86  68 /  80  50  30  20
MLB  87  68  82  70 /  80  50  40  20
VRB  88  69  82  69 /  70  50  40  20
LEE  85  67  84  67 /  80  40  20  20
SFB  86  67  85  65 /  80  50  20  20
ORL  86  68  85  68 /  80  50  30  20
FPR  88  69  83  69 /  70  50  50  30

&&

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

WEITLICH/KELLY

Hazardous weather outlook, Apr 20, 9:25 AM EDT, 3 hours 2 minutes before

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In the hours before

Special weather statement, Apr 20, 12:27 PM EDT, 0 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
1227 PM EDT MON APR 20 2015

FLZ058-059-201715-
OKEECHOBEE FL-ST. LUCIE FL-
1227 PM EDT MON APR 20 2015

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN ST. LUCIE AND
SOUTHEASTERN OKEECHOBEE COUNTIES UNTIL 115 PM EDT...

AT 1226 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR OKEECHOBEE...MOVING NORTHEAST AT 35 MPH.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
TREASURE ISLAND...OKEECHOBEE...TAYLOR CREEK...FOUR SEASONS ESTATES
AND CARLTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 2717 8088 2716 8089 2717 8091 2719 8091
      2720 8094 2722 8095 2722 8097 2723 8099
      2725 8098 2725 8099 2756 8062 2756 8060
      2733 8039 2720 8066 2721 8068 2719 8068
      2717 8073 2721 8079 2720 8083 2714 8087
TIME...MOT...LOC 1626Z 232DEG 32KT 2722 8088

KELLY

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 12:42 PM EDT	Special Weather Statement	MLB	Saint Lucie	63 min
Apr 20, 12:47 PM EDT	Special Marine Warning	MLB		58 min
Apr 20, 1:06 PM EDT	Severe Thunderstorm Warning	MLB	Okeechobee, Saint Lucie	39 min
Apr 20, 1:22 PM EDT	Special Marine Warning	MLB		83 min
Apr 20, 1:47 PM EDT	Special Weather Statement	MLB	Saint Lucie	58 min
Apr 20, 1:58 PM EDT	Special Weather Statement	MLB	Orange	62 min
Apr 20, 2:11 PM EDT	Areal Flood Advisory	MLB	Okeechobee	2 hr
Apr 20, 2:44 PM EDT	Special Marine Warning	MLB		91 min
Apr 20, 2:48 PM EDT	Special Marine Warning	MLB		57 min
Apr 20, 2:50 PM EDT	Special Weather Statement	MLB	Indian River, Martin, Okeechobee, Saint Lucie	55 min
Apr 20, 2:58 PM EDT	Special Weather Statement	MLB	Lake	62 min
Apr 20, 3:00 PM EDT	Special Weather Statement	MLB	Seminole	60 min
Apr 20, 3:06 PM EDT	Severe Thunderstorm Warning	MLB	Brevard	39 min
Apr 20, 3:10 PM EDT	Severe Thunderstorm Warning	MLB	Lake, Orange, Seminole	41 min
Apr 20, 3:14 PM EDT	Special Weather Statement	MLB	Osceola	31 min
Apr 20, 3:32 PM EDT	Special Weather Statement	MLB	Orange	43 min
Apr 20, 3:34 PM EDT	Special Weather Statement	MLB	Lake	56 min
Apr 20, 3:42 PM EDT	Special Weather Statement	MLB	Okeechobee	33 min
Apr 20, 3:59 PM EDT	Special Weather Statement	MLB	Brevard	46 min
Apr 20, 4:17 PM EDT	Special Marine Warning	MLB		58 min
Apr 20, 4:42 PM EDT	Special Weather Statement	MLB	Indian River	48 min

Nearby

Special Weather Statements in Florida, 2015 Every special weather statement in 2015

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.