Alert archive / Florida / Flash Flood Warnings in 1998

Flash Flood Warning 8, NWS Tampa Bay, FL

September 20, 1998Hillsborough County, Florida

NWS Tampa Bay, FL issued this flash flood warning at Sep 20, 1998, 1:47 PM EDT for Hillsborough County, Florida. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 20, 1998, 1:47 PM EDT (17:47 UTC)
Expired
Sep 20, 1998, 3:50 PM EDT
In force
2 hr
Issued by
NWS Tampa Bay, FL
Area
Whole counties

County Hillsborough County, FL

The radar

The Tampa radar (KTBW), 23 km from the middle of the area, began a volume at 17:49 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

Tampa Bay, FL (KTBW), launched 12:00Z, 5.8 hours before the alert went out and 23 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 1998-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 64 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 1998-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 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
64 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
700 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
69 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 
TTAA00 KTBW 201748
FFWTBW
FLC057-201950-

BULLETIN - EAS ACTIVATION REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
147 PM EDT SUN SEP 20 1998

THE NATIONAL WEATHER SERVICE IN RUSKIN HAS ISSUED A

* FLOOD WARNING FOR...
  HILLSBOROUGH COUNTY IN WEST CENTRAL FLORIDA

* UNTIL 350 PM EDT

* AT 143 PM...DOPPLER RADAR INDICATED HEAVY RAIN HAS FALLEN OVER
  NORTHERN HILLSBOROUGH COUNTY THIS MORNING AND EARLY THIS AFTERNOON.
  RAIN CONTINUES TO FALL FROM MANGO TO PLANT CITY TO NEAR THE TAMPA
  PALMS AND LUTZ AREA.  ANOTHER 1 TO 2 INCHES OF RAIN ARE POSSIBLE IN
  NORTHERN AND NORTHEASTERN HILLSBOROUGH COUNTY OVER THE NEXT HOUR.



MOST FLOODING DEATHS OCCUR IN AUTOMOBILES. NEVER ATTEMPT TO DRIVE
THROUGH WATER WHICH COVERS THE ROADS. PERSONS LIVING IN FLOOD PRONE
AREAS NEED TO TAKE ACTION TO PROTECT PROPERTY AND MOVE TO HIGHER
GROUND. STAY AWAY FROM STORM DRAINS AND DRAINAGE DITCHES.

What forecasters said that day

The local office's own words before this flash flood 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 flash flood warning went out at Sep 20, 9:51 AM EDT, 3 hours 56 minutes earlier.

Area forecast discussion, Sep 20, 9:51 AM EDT, 3 hours 56 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA / RUSKIN, FL
951 AM EDT SUN SEP 20 1998

AREA OF MOSTLY LIGHT RAIN WITH EMBEDDED HEAVIER SHOWERS STILL COVERING
A GOOD PORTION OF THE FA EARLY THIS MORNG VIA 88D RETURNS. ATTM THE
HEAVIEST PRECIP IS JUST OFFSHR SARASOTA COUNTY ASSOCIATED WITH SOME
DVLPG TSTMS. WITH MORNG RAOBS INDICATING DEEP LYRD TRPCL MSTR AND
ADEQUATE INSTABILITY ACRS THE FA WITH PWS AOA 2 AND LIS IN THE -2
TO -4 RANGE FA WILL CONT TO SEE PERIODS OF HEAVY RAINFALL AND ISOLD
TSTM TODAY.

IN ADDDITON...NEW AREAS OF CONVECTION NOTED ON SATL LOOP DVLPG OVER
THE ADJACENT GLF WATERS. WITH DEEP SWLY FLOW ACRS THE REGION INDICATED
BY VADS AND RAOBS...THIS CONVECTION WILL LIKELY MOVE TOWARD THE W-
CNTRL FL COAST LATER THIS MORNG INTO THE PM HOURS WITH ADDITIONAL
HEAVY RAINFALL AMOUNTS. WITH FA ALREADY QUITE SATURATED FROM HEAVY
RAINFALL AMOUNTS THE LAST FEW DAYS WILL HAVE TO CONT TO MONITOR 88D
AND SATL TRENDS REMAINDER OF THIS MORNG TO SEE IF A FLOOD WATCH MAY
BE NEEDED FOR PORTIONS OF MY FA LATER TODAY. ATTM ONLY CHANGE TO
PREVIOUS PACKAGE WILL BE TO TWEEK MAX TEMPS DOWN SOME TO ACCOUNT FOR
THE CONSIDERABLE CLOUD COVER AND ONGOING AND EXPECTED PRECIP.

MCMICHAEL

In the hours before

Special weather statement, Sep 20, 11:28 AM EDT, 2 hours 19 minutes before
FLZ039-042-043-048>052-055>057-060>062-065-202330-

WEST CENTRAL AND SOUTHWEST FLORIDA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
1128 AM EDT SUN SEP 20 1998

...SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED THIS AFTERNOON SOME
   WITH LOCALLY HEAVY RAINFALL...
...FLOOD WARNINGS IN EFFECT ON THE ALAFIA...MANATEE...LITTLE MANATEE
   AND MYAKKA RIVERS...

PERIODS OF RAIN AND ISOLATED HEAVIER THUNDERSTORMS ARE EXPECTED
OVER WEST CENTRAL AND SOUTHWEST FLORIDA THIS AFTERNOON WITHIN A WARM
AND HUMID AIRMASS WHICH COVERS THE STATE. SOUTH TO SOUTHWEST WINDS
WILL CONTINUE TO PUMP ABUNDANT TROPICAL MOISTURE NORTHWARD FROM THE
CARIBBEAN THROUGH TONIGHT WHICH WILL CONTINUE TO PROVIDE FUEL FOR
WIDESPREAD AND LOCALLY HEAVY PRECIPITATION.

ALTHOUGH RAINFALL AMOUNTS IN MANY AREAS WILL BE UNDER AN INCH...SOME
HEAVIER AMOUNTS OF TWO TO THREE INCHES ARE POSSIBLE. THESE LOCALIZED
HEAVY RAINS WILL CAUSE THE PONDING OF WATER ON ROADWAYS AND THE
TEMPORARY FLOODING OF LOW LYING OR POOR DRAINAGE AREAS.

SEVERAL AREAS HAVE ALREADY RECEIVED FROM THREE TO SIX INCHES OF RAIN
SINCE LAST WEDNESDAY...MOST NOTABLY FROM SARASOTA THROUGH LAKELAND
AND WINTERHAVEN...AND ALSO IN THE BROOKSVILLE AND SOUTH FORT MYERS
AREAS. THESE AREAS WILL BE PARTICULARLY VULNERABLE TO ADDITIONAL
HEAVY RAINFALL AMOUNTS THIS AFTERNOON. IF YOU LIVE IN FLOOD PRONE
AREAS OR ALONG RIVERS OR FASTER FLOWING STREAMS...REMAIN ALERT TO ANY
RAPID RISES IN WATER LEVELS AND BE READY TO MOVE TO HIGHER GROUND IF
FLOODING IS OBSERVED.

IN ADDITION TO THE HEAVY RAINS ISOLATED THUNDERSTORMS WILL ALSO
POSE A THREAT FOR LIGHTNING AND BRIEF GUSTY WINDS TO 30 MPH. AT THE
FIRST SIGN OF A THUNDERSTORM MOVE INDOORS IMMEDIATELY.

MCMICHAEL
Special weather statement, Sep 20, 11:28 AM EDT, 2 hours 19 minutes before
FLZ039-042-043-048>052-055>057-060>062-065-202330-

WEST CENTRAL AND SOUTHWEST FLORIDA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
1128 AM EDT SUN SEP 20 1998

...SHOWERS AND ISOLATED THUNDERSTORMS EXPECTED THIS AFTERNOON SOME
   WITH LOCALLY HEAVY RAINFALL...
...FLOOD WARNINGS IN EFFECT ON THE ALAFIA...MANATEE...LITTLE MANATEE
   AND MYAKKA RIVERS...

PERIODS OF RAIN AND ISOLATED HEAVIER THUNDERSTORMS ARE EXPECTED
OVER WEST CENTRAL AND SOUTHWEST FLORIDA THIS AFTERNOON WITHIN A WARM
AND HUMID AIRMASS WHICH COVERS THE STATE. SOUTH TO SOUTHWEST WINDS
WILL CONTINUE TO PUMP ABUNDANT TROPICAL MOISTURE NORTHWARD FROM THE
CARIBBEAN THROUGH TONIGHT WHICH WILL CONTINUE TO PROVIDE FUEL FOR
WIDESPREAD AND LOCALLY HEAVY PRECIPITATION.

ALTHOUGH RAINFALL AMOUNTS IN MANY AREAS WILL BE UNDER AN INCH...SOME
HEAVIER AMOUNTS OF TWO TO THREE INCHES ARE POSSIBLE. THESE LOCALIZED
HEAVY RAINS WILL CAUSE THE PONDING OF WATER ON ROADWAYS AND THE
TEMPORARY FLOODING OF LOW LYING OR POOR DRAINAGE AREAS.

SEVERAL AREAS HAVE ALREADY RECEIVED FROM THREE TO SIX INCHES OF RAIN
SINCE LAST WEDNESDAY...MOST NOTABLY FROM SARASOTA THROUGH LAKELAND
AND WINTERHAVEN...AND ALSO IN THE BROOKSVILLE AND SOUTH FORT MYERS
AREAS. THESE AREAS WILL BE PARTICULARLY VULNERABLE TO ADDITIONAL
HEAVY RAINFALL AMOUNTS THIS AFTERNOON. IF YOU LIVE IN FLOOD PRONE
AREAS OR ALONG RIVERS OR FASTER FLOWING STREAMS...REMAIN ALERT TO ANY
RAPID RISES IN WATER LEVELS AND BE READY TO MOVE TO HIGHER GROUND IF
FLOODING IS OBSERVED.

IN ADDITION TO THE HEAVY RAINS ISOLATED THUNDERSTORMS WILL ALSO
POSE A THREAT FOR LIGHTNING AND BRIEF GUSTY WINDS TO 30 MPH. AT THE
FIRST SIGN OF A THUNDERSTORM MOVE INDOORS IMMEDIATELY.

MCMICHAEL

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 20, 3:54 PM EDTFlash Flood WarningTBWHillsborough111 min

Nearby

Flash Flood Warnings in Florida, 1998Every flash flood warning in 1998

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.