Alert archive / Florida / Severe Thunderstorm Warnings in 2006

Severe Thunderstorm Warning 9, NWS Tampa Bay, FL

April 21, 2006Hernando County, Florida

NWS Tampa Bay, FL issued this severe thunderstorm warning at Apr 21, 2006, 2:52 PM EDT for Hernando County, Florida. It was in force for 23 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 21, 2006, 2:52 PM EDT (18:52 UTC)
Expired
Apr 21, 2006, 3:15 PM EDT
In force
23 min
Issued by
NWS Tampa Bay, FL
Area
Counties, with a storm outline in the text

County Hernando County, FL

The radar

The Tampa radar (KTBW), 94 km from the middle of the area, began a volume at 18:56 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, 6.9 hours before the alert went out and 94 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 2006-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 373 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 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 2006-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 square meters per square second.1939Sfc1 km3 km6 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
373 J/kg
Mixed-layer CIN
-105 J/kg
Mixed-layer LCL
973 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
-20 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.

000 
WUUS52 KTBW 211853
SVRTBW
FLC053-211915-
/O.NEW.KTBW.SV.W.0009.060421T1852Z-060421T1915Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
252 PM EDT FRI APR 21 2006

THE NATIONAL WEATHER SERVICE IN RUSKIN HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL HERNANDO COUNTY IN FLORIDA.

* UNTIL 315 PM EDT

* AT 252 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
  SEVERE THUNDERSTORM WITH LARGE HAIL AND DAMAGING WINDS...MOVING    
  INTO BROOKSVILLE. THE STORM WAS DEVELOPING SLOWLY SOUTHWARD.

* THE SEVERE THUNDERSTORM WILL AFFECT...
  BROOKSVILLE.
  SPRING HILL.

SEVERE THUNDERSTORMS CONTAIN WIND GUSTS OF 60 MPH OR HIGHER...AND
HAIL THE SIZE OF PENNIES OR LARGER. MOVE TO A PLACE OF SAFETY.

NICKEL TO POSSIBLY QUARTER SIZE HAIL IS LIKELY. MOVE INDOORS 
IMMEDIATELY.

&&

LAT...LON 2860 8250 2850 8257 2847 8245 2855 8234

$$

88
1 follow-up statement
000 
WWUS52 KTBW 211906
SVSTBW

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
304 PM EDT FRI APR 21 2006

FLC053-211915-
/O.CON.KTBW.SV.W.0009.000000T0000Z-060421T1915Z/
HERNANDO-
304 PM EDT FRI APR 21 2006

...A SEVERE THUNDERSTORM WARNING CONTINUES FOR CENTRAL HERNANDO
COUNTY UNTIL 315 PM EDT...

AT 250 PM EDT...A SKYWARN SPOTTER REPORTED PEA SIZE HAIL FROM A 
WEAKER THUNDERSTORM IN BEVERLY HILLS...IN NORTHERN CITRUS COUNTY.  
THE STORM LOCATED NEAR STATE ROAD 50 BETWEEN THE SUNCOAST PARKWAY 
AND HIGHWAY 19 IS LIKELY PRODUCING MUCH LARGER HAIL.  THE STORM IS 
DEVELOPING SOUTH AT AROUND 5 MPH.

THE SEVERE THUNDERSTORM WILL AFFECT...
  NORTH BROOKSVILLE.
  BROOKSVILLE.
  SPRING HILL NORTH OF SPRING HILL DRIVE.

THE SEVERE THUNDERSTORM IS ALSO CAPABLE OF PRODUCING...
  QUARTER SIZE HAIL.
  60 MPH WIND GUSTS.
  EXCESSIVE AND DEADLY CLOUD-TO-GROUND LIGHTNING.

MOVE INTO A STURDY BUILDING IMMEDIATELY REPORT SEVERE WEATHER TO THE
NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE
NATIONAL WEATHER SERVICE FORECAST OFFICE IN RUSKIN.

&&

LAT...LON 2860 8250 2850 8257 2847 8245 2855 8234

$$

88

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 Tampa Bay, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 21, 1:46 PM EDT, 1 hour 6 minutes earlier.

Area forecast discussion, Apr 21, 1:46 PM EDT, 1 hour 6 minutes before
WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY RUSKIN FL
146 PM EDT FRI APR 21 2006

.SHORT TERM (TNGT-SUN)...MID/UPPER LEVEL RIDGING WILL BE SHIFTING
EAST OUT INTO THE ATLANTIC TONIGHT AS THE NEXT SHORTWAVE TROUGH
MOVES EAST AND ACROSS THE SOUTHEAST U.S. SATURDAY FOLLOWED BY WEAK
RIDGING ON SUNDAY.  AT THE SURFACE...A COOL FRONT ASSOCIATED WITH
THE TROUGH WILL MOVE ACROSS NORTH FLORIDA SATURDAY AND INTO THE
REGION SATURDAY NIGHT BEFORE WASHING OUT ACROSS SOUTH FLORIDA
SUNDAY MORNING.

FOR TONIGHT...SOUTHWEST TO WEST WINDS WITH THE SEA BREEZE WILL
DIMINISH AND BECOME SOUTH TO SOUTHEAST OVERNIGHT.  SKIES ARE ONCE
AGAIN EXPECTED TO BE MOSTLY CLEAR TO PARTLY CLOUDY WITH SOME LATE
NIGHT LOW CLOUDS AND PATCHY FOG POSSIBLE...MAINLY ACROSS THE NATURE
COAST.  LOW TEMPERATURES WILL BE MAINLY IN THE 60S...EXCEPT AROUND 70
FROM TAMPA BAY SOUTHWARD ALONG THE GULF COAST.

ON SATURDAY THE CURRENT FORECAST STILL LOOKS ON TRACK AS MODELS
PUSH THE BOUNDARY INTO THE FLORIDA PANHANDLE WITH SOME UPPER LEVEL
ENERGY MOVING ACROSS GEORGIA AND NORTH FLORIDA.  THIS WOULD KEEP
THE BEST CHANCES OF RAIN ACROSS THE NATURE COAST CLOSER TO THE UPPER
LEVEL SUPPORT WHILE THE GENERAL SOUTHWEST TO WEST FLOW WOULD FAVOR
THE EASTERN HALF OF THE PENINSULA.  FOR NOW WILL CONTINUE WITH
CURRENT CHANCE POPS ACROSS THE NATURE COAST WITH SLIGHT CHANCE POPS
ELSEWHERE.  ADDITIONAL CLOUDS AND SOUTHWEST TO WEST FLOW WILL KEEP
HIGH TEMPERATURES A LITTLE COOLER THAN TODAY WITH A RANGE FROM THE
UPPER 70S TO AROUND 80 ALONG THE GULF COAST TO UPPER 80S INLAND.

FOR SATURDAY NIGHT THE UPPER LEVEL ENERGY AND DEEP MOISTURE WILL BE
SHIFTING EAST OUT INTO THE ATLANTIC SO JUST EXPECT TO SEE SOME CLOUDS
LEFT BEHIND WITH THE BOUNDARY.  THE BOUNDARY SHOULD REACH THE
INTERSTATE 4 CORRIDOR AROUND SUNRISE WITH WINDS SHIFTING TO THE NORTH
BEHIND IT AND RATHER LIGHT AND VARIABLE AHEAD OF IT.  ABUNDANT LOW
LEVEL MOISTURE ALONG WITH THE BOUNDARY IN THE VICINITY WILL LIKELY
LEAD TO SOME AREAS OF LOW CLOUDS AND FOG SATURDAY NIGHT. TEMPERATURES
WILL ONCE AGAIN MAINLY FALL INTO THE 60S...EXCEPT AROUND 70 FROM
TAMPA BAY SOUTHWARD ALONG THE GULF COAST.

ON SUNDAY WEAK HIGH PRESSURE WILL SETUP OVER THE EASTERN GULF AND
FLORIDA WITH THE REMNANTS OF THE FRONT STRETCHED WEST TO EAST ACROSS
SOUTH FLORIDA.  SOME DRIER AIR WILL OVERSPREAD THE NORTHERN AND
CENTRAL ZONES UNDER MOSTLY SUNNY SKIES WITH SOME LOW LEVEL MOISTURE
LINGERING ACROSS THE SOUTH NEAR THE REMNANTS OF THE FRONT KEEPING
SKIES PARTLY CLOUDY WITH AN OUTSIDE CHANCE OF A SHOWER OVER INLAND
AREAS ONCE THE SEA BREEZE GETS GOING.  FOR NOW WILL LEAVE SILENT
10 POPS IN FOR THE SOUTHERN INLAND SECTIONS.  HIGH TEMPERATURES ARE
EXPECTED TO RANGE FROM THE UPPER 70S TO AROUND 80 ALONG THE GULF
COAST TO NEAR 90 INLAND.

.LONG TERM (SUN NGT-FRI)...DRY HIGH PRESSURE IN PLACE ACROSS THE
AREA FOR SUNDAY NIGHT THROUGH EARLY WEDNESDAY.  MAY HAVE SOME FIRE
WEATHER CONCERNS MONDAY AFTERNOON AS THE DRIER AIR FILTERS DOWN THE
STATE WITH HIGH PRESSURE BUILDING IN.  A WEAKENING COLD FRONT WILL
THEN APPROACH THE AREA WEDNESDAY NIGHT.  MODELS STILL VARIED ON HOW
THEY HANDLE THE FRONT BUT ARE STARTING TO COME INTO BETTER AGREEMENT.
LATEST GFS STALLS IT ACROSS NORTH FLORIDA WEDNESDAY AND THEN KEEPS
WEAK LOW PRESSURE OVER THE AREA AS UPPER SHORTWAVES MOVE OVER THE
STATE THROUGH FRIDAY.  DGEX ALSO STALLS THE FRONT ACROSS NORTH
FLORIDA BUT NOT UNTIL THURSDAY MORNING...WITH WEAK RIDGING BUILDING
IN AS THE UPPER SHORTWAVES MOVE OVER THE AREA.  EITHER WAY...RIGHT
NOW IT LOOKS LIKE WE WILL HAVE LIMITED MOISTURE AND ENERGY WITH THE
STALLING FRONT THURSDAY SO HAVE KEPT POPS AT 10 PERCENT...EXCEPT 20
PERCENT ACROSS THE NORTH WHERE THEY WILL HAVE BEST CHANCES.  UPPER
LEVEL ENERGY MOVING OVER THE AREA FRIDAY WILL ALLOW FOR SOME ISOLATED
STORMS. TEMPERATURES WILL CONTINUE GENERALLY IN THE MID TO UPPER 80S
FOR HIGHS AND IN THE MID 50S NORTH TO THE MID 60S ELSEWHERE FOR LOWS.

&&

.MARINE...SOUTH TO SOUTHWEST FLOW TONIGHT WILL BECOME SOUTHWEST TO
WEST SATURDAY AHEAD OF THE BOUNDARY AND THEN BECOME RATHER
VARIABLE ON SUNDAY WITH STILL A WEST TO NORTHWEST SEA BREEZE EXPECTED
NEAR THE COAST DURING THE AFTERNOON.  HIGH PRESSURE WILL SETTLE OVER
THE AREA EARLY NEXT WEEK WITH RATHER LIGHT AND VARIABLE WINDS WITH A
SEA BREEZE DEVELOPING EACH AFTERNOON.  IN GENERAL WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY CRITERIA THROUGH THE PERIOD.

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE INTO EARLY TONIGHT.  MAY
AGAIN SEE SOME LOCAL 3-5 MILE VISIBILITIES IN FOG WITH SOME SCATERRED
TO BROKEN LOW CLOUDS TOWARD MORNING SATURDAY...BUT WINDS SHOULD STAY
AROUND 5 KNOTS OVERNIGHT AND KEEP THE FOG DEVELOPMENT MORE LOCALIZED
THAN IT WAS THIS MORNING.  THE LOW CLOUDS AND FOG SHOULD LIFT/BURN
OFF SHORTLY AFTER SUNRISE WITH VFR CONDITIONS FOR THE REMAINDER OF
THE DAY.

&&

.FIRE WEATHER...NO FIRE WEATHER HAZARDS EXPECTED NEXT COUPLE OF
DAYS...BUT COULD SEE 1 TO 3 HOURS OF RELATIVE HUMIDITY VALUES AROUND
OR BELOW 35 PERCENT SUNDAY AFTERNOON OVER THE NORTHERN INTERIOR.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  71  85  70  86 /   5  20  10   0
FMY  69  88  69  89 /   5  20  10  10
GIF  69  89  69  89 /  20  20  10   0
SRQ  70  84  68  84 /   5  20  10   0
BKV  64  87  62  88 /   5  30  10   0

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.

&&

SHORT TERM/MARINE...PRC
LONG TERM/AVIATION/FIRE WX....JLC
Hazardous weather outlook, Apr 21, 4:42 AM EDT, 10 hours 10 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
442 AM EDT FRI APR 21 2006

FLZ039-042-043-048>052-055>057-060>062-065-212000-
LEVY-CITRUS-SUMTER-HERNANDO-PASCO-PINELLAS-HILLSBOROUGH-POLK-
MANATEE-HARDEE-HIGHLANDS-SARASOTA-DE SOTO-CHARLOTTE-LEE-
442 AM EDT FRI APR 21 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
FLORIDA AND WEST CENTRAL FLORIDA.

.DAY ONE...TODAY AND TONIGHT

PATCHY DENSE FOG IS POSSIBLE ACROSS PORTIONS OF WEST CENTRAL
FLORIDA THIS MORNING. MOTORISTS THIS MORNING SHOULD SLOW DOWN IN
FOG...USE LOW BEAM HEADLIGHTS...AND ALLOW EXTRA TRAVEL TIME. THE FOG
SHOULD BURN OFF BY MID MORNING.

ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS INTERIOR SECTIONS OF
WEST CENTRAL FLORIDA THIS AFTERNOON. PEOPLE WITH OUTDOOR
ACTIVITIES SHOULD STAY AWARE OF THE SKY...AND MOVE INDOORS IF
LIGHTNING IS SEEN OR THUNDER IS HEARD.

BEFORE THE ARRIVAL OF THE SEA BREEZE TODAY...LOW RELATIVE
HUMIDITY VALUES AND SEA BREEZE THUNDERSTORMS WILL HAVE THE
POTENTIAL TO CREATE DANGEROUS FIRE WEATHER CONDITIONS THIS
AFTERNOON ACROSS INTERIOR PORTIONS OF WEST CENTRAL FLORIDA. THESE
CONDITIONS WILL BE FAVORABLE FOR INCREASED SPREAD OF ANY FIRE THAT
MAY START TODAY. RESIDENTS AND VISITORS OF WEST CENTRAL AND
SOUTHWEST FLORIDA SHOULD BE EXTRA CAREFUL WITH ANY OUTDOOR OPEN
FLAMES OR BARBECUES TODAY.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO SIGNIFICANT HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 3:09 PM EDTSevere Thunderstorm WarningTBWCitrus51 min
Apr 21, 3:16 PM EDTSevere Thunderstorm WarningTBWHernando44 min
Apr 21, 3:53 PM EDTSevere Thunderstorm WarningTBWLevy37 min

Nearby

Severe Thunderstorm Warnings in Florida, 2006Every severe thunderstorm warning in 2006

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.