Alert archive / Florida / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 109, NWS Melbourne, FL

October 20, 2004Osceola County, Florida

NWS Melbourne, FL issued this severe thunderstorm warning at Oct 20, 2004, 4:19 PM EDT for Osceola County, Florida. It was in force for 41 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
Oct 20, 2004, 4:19 PM EDT (20:19 UTC)
Expired
Oct 20, 2004, 5:00 PM EDT
In force
41 min
Issued by
NWS Melbourne, FL
Area
Counties, with a storm outline in the text

County Osceola County, FL

The radar

The Melbourne radar (KMLB), 41 km from the middle of the area, began a volume at 20:21 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Tampa Bay, FL (KTBW), launched 12:00Z, 8.3 hours before the alert went out and 144 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, Tampa Bay, FL at 12:00Z on 2004-10-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2984 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, Tampa Bay, FL at 12:00Z on 2004-10-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 81 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
2984 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
503 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
81 m²/s²
0-3 km storm-relative helicity
95 m²/s²
Significant tornado parameter
1.7
Supercell composite
6.8

Open this sounding in Storm Lab

The text

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

000 
WUUS52 KMLB 202019
SVRMLB
FLC097-202100-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MELBOURNE FL
418 PM EDT WED OCT 20 2004

THE NATIONAL WEATHER SERVICE IN MELBOURNE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN OSCEOLA COUNTY
  IN EAST CENTRAL FLORIDA

* UNTIL 500 PM EDT

* AT 411 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM OVER KENANSVILLE...OR ABOUT 3 MILES NORTHEAST
  OF KENANSVILLE...MOVING SOUTH AT 15 MPH.

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS IN EXCESS OF 58 MILES AN
HOUR...LARGE HAIL...DEADLY LIGHTNING AND VERY HEAVY RAIN. IF
THE STORM APPROACHES YOU...MOVE TO AN INTERIOR ROOM ON THE LOWEST
FLOOR.

LAT...LON 2801 8089 2795 8109 2764 8100 2763 8085

$$

SPRATT

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Oct 20, 2:50 PM EDT, 1 hour 29 minutes earlier.

Area forecast discussion, Oct 20, 2:50 PM EDT, 1 hour 29 minutes before
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
250 PM EDT WED OCT 20 2004

.DISCUSSION...

CONVECTIVE ACTIVITY GOT A LATE START THIS AFTN DUE TO MID/UPPER
DEBRIS CLOUDS...HOWEVER THERE IS LESS CONVECTIVE INHIBITION (MID
LEVEL DRY AIR) THAN WHAT WAS IN PLACE TUE AFTN AND MID LEVEL TEMPS
ARE UNIFORMLY COOLER THAN THIS TIME TUE AS WELL (IT WAS MID LEVEL
COOLING DURING THE EVENING BEHIND A STRONGER THAN ANTICIPATED H50
VORTLOBE WHICH LED YOURS TRULY TO HORRIBLY UNDERFORCAST COEVERAGE
AND ESPECIALLY INTENISTY OF LAST NIGHTS PRECIP/STORMS). STEERING
FLOW IS A SOLID 20-25KT WHICH SHOULD PUSH ACTIVITY SE AT A MUCH
FASTER CLIP THAN TUE...AND SHOULD LEAD TO LESS COVERAGE BY ONSET OF
THE EVENING PERIOD (00Z/8PM). HAVE PAINTED HIGHEST COVERAGE FOR THE
FIRST 1-2HR FROM SRN BREVARD SWD (40) WITH 30 ACROSS THE SOUTH INTR
AND 20 TO THE NORTH. SLOW CLEARING WITH LOW LEVELS REMAINING MOIST
AND A LIGHT NRLY DRAINAGE FLOW DEVELOPING...WHICH SHOULD ALLOW FOR
A LITTLE COOLER MINS. HAVE ADDED SOME PATCHY LATE NIGHT FOG TO THE
ZONES.

THU-FRI...AMPLIFYING UPR PATTERN OVER THE REGION WITH STRONG
GRADIENT FLOW ON THE N AND WEST SIDES OF DEVELOPING GALE EAST OF THE
CAROLINAS. A MARINE SURGE WILL WRAP SOUTHWARD AROUND SYSTEM ALONG
THE SE COAST. VEERING WINDS LOCALLY WL BECOME ONSHORE FAIRLY EARLY
IN THE DAY WITH AN INCREASE IN SPEED DURING THE AFTERNOON. THE WIND
SURGE OVER THE MARINE AREA WILL BRING AN INCREASE IN BOTH LL
MOISTURE AND CLOUDINESS. WILL KEEP A SLIGHT CHANCE OF SHOWERS
MENTIONED ALONG THE COAST THROUGH THU NIGHT DUE TO FRICTIONAL
CONVERGENCE. FRI DRYING INDICATED AS RIDGING BECOMES ESTABLISHED
FROM THE GULF NORTH INTO THE TN VALLEY. NE FLOW WITH MILD TEMPS DUE
TO MARINE INFLUENCE AND ONLY CLOUDS OF NOTE WL BE SCT STRATOCU
WORKING IN FROM THE MARINE AREA. SHOWERS WL LIKELY BE CONFINED TO
THE MARINE AREA WITH SOME SPRINKLES MAKING IT THE THE COAST...
HOWEVER WL LEAVE MENTION OUT OF FORECAST AT THIS TIME.

WEEKEND...PLEASANT CONDITIONS OVERALL AS UPR RIDGE WL MAINTAIN OVER
THE GULF WHILE FLATTENING W/TIME. ELSEWHERE UPR PATTERN BECOMES
INCREASINGLY ZONAL ADROSS THE CONUS INTO EARLY NEXT WEEK. LOCAL
WINDS WILL CONTINUE WITH ONSHORE TENDENCY WITH AIRMASS AND DAILY
HIGHS AND LOWS INFLUENCED BY MARINE AREA. A WEAK FRONT IS ADVERTISED
MAKING PROGRESS INTO N FL ON MON AND THIS MAY PRODUCE A FEW BRIEF
SHOWERS NEAR THE FRONTAL ZONE. OTHERWISE...NOT MUCH MORE THAN A WIND
SHIFT WL BE ASCD WITH FRONTAL PASSAGE.

EXTENDED...MOSTLY FAIR CONDITIONS ARE EXPECTED THROUGH THE MIDDLE OF
NEXT WEEK AS HIGH PRESSURE CONTINUES TO DOMINATE THE SOUTHEAST
STATES.

&&

.MARINE...SEAS WL BUILD LATE THU IN RESPONSE TO MARINE SURGE WORKING
SOUTH FROM DEVELOPING GALE OFF THE CAROLINAS. HEADLINES WILL BE
LIKELY BY THU EVENING FOR A BUILDING NE SWELL. LATEST WAVE WATCH SEA
HEIGHTS HAVE DECREASED SLIGHTLY BUT 8-9 FT IS INDICATED @41009
THROUGH THE WEEKEND.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  68  84  67  79 /  20  20  20  20
MCO  70  86  67  83 /  20  10   0   0
MLB  70  84  69  83 /  40  20  20  20
VRB  70  86  69  83 /  40  20  20  20

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
 FLOOD WARNING MIDDLE ST JOHNS RIVER BASIN.

&&

SHORT TERM...CRISTALDI
LONG TERM...PENDERGRAST
Hazardous weather outlook, Oct 20, 4:33 AM EDT, 11 hours 46 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MELBOURNE FL
433 AM EDT WED OCT 20 2004

AMZ550-555-570-575-FLZ041-044>047-053-054-058-059-064-141-144-147-
202000-
COASTAL VOLUSIA-COCOA BEACH TO JUPITER INLET 20 NM TO 60 NM OFFSHORE-
COCOA BEACH TO JUPITER INLET OUT TO 20 NM-
FLAGLER BEACH TO COCOA BEACH 20 NM TO 60 NM OFFSHORE-
FLAGLER BEACH TO COCOA BEACH OUT TO 20 NM-INDIAN RIVER-
INLAND VOLUSIA-MARTIN-NORTHERN BREVARD-NORTHERN LAKE-OKEECHOBEE-
ORANGE-OSCEOLA-SEMINOLE-SOUTHERN BREVARD-SOUTHERN LAKE-ST. LUCIE-
433 AM EDT WED OCT 20 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA.

.DAY ONE...TODAY.

...THUNDERSTORM IMPACT...
ABUNDANT MOISTURE AND AN UPPER LEVEL DISTURBANCE MOVING ACROSS THE
REGION WILL ALLOW SCATTERED LIGHTNING STORMS TO DEVELOP FROM MID
MORNING THROUGH THE AFTERNOON. STORMS MAY FIRST DEVELOP ALONG
BOUNDARIES SET OUT BY LAST NIGHTS STORMS AS THEY PROPAGATE SOUTHWARD
ACROSS THE AREA.

THE MAIN CONCERN WITH ANY STORMS THAT DEVELOP WILL BE THE OCCURRENCE
OF DEADLY CLOUD TO GROUND LIGHTNING. STORMS MAY ALSO PRODUCE BRIEF
WIND GUSTS TO 40 MPH. STORM MOTION TODAY WILL BE FROM WEST TO
EAST...HOWEVER NEW STORMS WILL DEVELOP SOUTHWARD INTO MORE UNSTABLE
AIR. BE SURE TO GET INDOORS AND AWAY FROM WINDOWS AT THE FIRST SIGN
OF DETERIORATING CONDITIONS.

...MARINE THUNDERSTORM GUST IMPACT...
MARINERS SHOULD BE ALERT FOR STORMS APPROACHING FROM THE WEST. STORMS
WILL MOVE EAST AT 25 MPH CROSSING THE INTRACOASTAL WATERS BEFORE
WEAKENING. STORMS WILL ALSO CONTINUE TO DEVELOP ALONG THE WARMER
WATERS OF THE GULF STREAM.

...RIVER FLOOD IMPACT...
THE MIDDLE SAINT JOHNS RIVER BASIN CONTINUES ABOVE FLOOD STAGE AND IS
FORECAST TO REMAIN NEARLY STEADY INTO NEXT WEEK WITH ONLY A VERY
SLIGHT FALL IN THE RIVER LEVEL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH WEDNESDAY.
A DEVELOPING LOW OFF THE MID ATLANTIC COAST WILL INCREASE WINDS AND
SEAS OVER THE COASTAL WATERS ON FRIDAY. ADDITIONALLY...LONG PERIOD
OCEAN SWELLS WILL DEVELOP BY WEEKS END AND CONTINUE THROUGH THE
WEEKEND. THOSE PLANNING TO GO TO THE BEACH SHOULD BE AWARE THAN THESE
SWELLS WILL PRODUCE DANGEROUS RIP CURRENTS THIS WEEKEND.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.

BLOTTMAN

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 19, 8:33 PM EDTSevere Thunderstorm WarningMLBBrevard, Volusia57 min
Oct 20, 6:03 PM EDTTornado WarningMLBBrevard27 min
Oct 20, 6:11 PM EDTSpecial Marine WarningMLB64 min

Nearby

Severe Thunderstorm Warnings in Florida, 2004Every severe thunderstorm warning in 2004

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.