Alert archive / Florida / Flash Flood Warnings in 1998

Flash Flood Warning 9, NWS Tampa Bay, FL

September 20, 1998Hillsborough County, Florida

NWS Tampa Bay, FL issued this flash flood warning at Sep 20, 1998, 3:54 PM EDT for Hillsborough County, Florida. It was in force for 111 min. 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, 3:54 PM EDT (19:54 UTC)
Expired
Sep 20, 1998, 5:45 PM EDT
In force
111 min
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 19:54 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, 7.9 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 201956
FFWTBW
FLC057-202145-

BULLETIN - EAS ACTIVATION REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL
354 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 545 PM EDT

* AT 352 PM...DOPPLER RADAR INDICATED RADAR INDICATES THAT BETWEEN 4
  TO 7 INCHES OF RAIN HAS FALLEN OVER NORTHERN AND NORTHEASTERN
  HILLSBOROUGH COUNTY BETWEEN 9 AM AND 3 PM.  ADDITIONAL MODERATE TO
  HEAVY RAIN IS REDEVELOPING OVER THE AREA AND SOUTHWARD TO THE
  RIVERVIEW AND LITHIA AREAS INCLUDING PORTIONS OF THE BRANDON AND
  MANGO AREAS.  PERSONS LIVING IN LOW LYING AREAS AND ALONG STREAMS
  PARTICULARLY IN NORTHEAST HILLSBOROUGH COUNTY SHOULD TAKE ACTIONS
  TO SAVE THEIR PROPERTY.

* ALTHOUGH MOST OF THE AREA WILL ONLY SEE RAINFALL OF LESS THAN 1/2
  INCH...A FEW AREAS COULD SEE UP TO AN ADDITIONAL 2 INCHES THIS
  AFTERNOON.

  PERSONS ALONG STREAMS OR FASTER FLOWING RIVERS NEED TO MOVE TO
  HIGHER GROUND. DO NOT ATTEMPT TO WALK OR DRIVE THROUGH WATER WHICH
  IS FLOWING.

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, 2:47 PM EDT, 1 hour 7 minutes earlier.

Area forecast discussion, Sep 20, 2:47 PM EDT, 1 hour 7 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY AREA / RUSKIN, FL
247 PM EDT SUN SEP 20 1998

LARGE AREAS OF MODERATE TO HEAVY RAIN CONT TO BE INDICATED BY 88D
ACRS PORTIONS OF THE FA EARLY THIS AFTERNOON. ONE AREA HAS PERSISTED
OVER POLK AND HILLSBOROUGH COUNTIES WITH ANOTHER ONE OVER SARASOTA...
CHARLOTTE AND LEE COUNTIES. RADAR RAINFALL ESTIMATES IN THESE AREAS
SINCE EARLY THIS MORNG HAS BEEN ON THE ORDER OF 2 TO 4 INCHES. THESE
HVY RAINS HAVE PROMPTED URBAN FLOOD ADVISORIES AND FLOOD WARNINGS FOR
HILLSBOROUGH COUNTY. AFTER COORD WITH WSFO MIA HAVE ALREADY UPDATED
ZONES TO PUT A LARGE PORTION OF W-CENTRAL FL UNDER A FLOOD WATCH FOR
THE REMAINDER OF THIS AFTERNOON AND INTO TONIGHT. LOOKING OVER SATL
TRENDS MAY BEGIN TO SEE SOME SUN DVLP NEXT HR OR SO ESPECIALLY ALONG
W COASTAL ZONES. THIS SFC HTG IN COMBINATION WITH PWS ABV 2 WILL
LIKELY LEAD TO ADDITIONAL RAIN OR TSTM DVLPMT INTO THE EVENING HRS...
THUS WOULD SUGGEST AT LEAST A 50% POP FOR MOST ZONES IN THE 5 PM
PACKAGE WITH MENTION OF LOCALLY HVY RAINS AS WELL.

WELL NO REAL OVERALL SYNOPTIC SCALE CHANGES EXPECTED ACRS THE FA
DURING THIS FCST PERIOD. DEEP LYRD MSTR ASSOCIATED WITH REMNANTS OF
TRPCL STORM HERMINE NOW OVER NE LA IS PROGD TO CONT MOVG N-NEWD INTO
THE TN/MS VALLEY AREAS THRU THE PERIOD. UPR LVL RDG OVER THE ATL IS
PROGD TO BUILD W THRU MONDAY WITH SFC RDG AXIS SHIFTING SLIGHTLY N
TO THE S-CENTRAL PENINSULA THRU THE PERIOD. THIS WILL RESULT IN A
CONTD S TO SWLY DEEP LYRD FLOW ACRS THE FA WHICH WILL KEEP PWS AOA
2. THIS DEEP LYRD MSTR ALONG WITH DAYTIME SFC HTG AND ADEQUATE
INSTABILTY WILL CONT TO RESULT IN SCT HEAVY LOCALIZED RAINS AND WDLY
SCT TSTMS THRU MONDAY. ATTM I PREFER A BLEND OF THE AVN/NGM POPS AND
RECOMMEND AT LEAST LIKELY CATEGORY POPS FOR MONDAY. BEYOND THIS DRIER
AIR AND SUBSIDENCE FROM UPR LVL LOW NOW OVER THE SERN BAHAMAS MOVG
WWD MAY LWR POPS SOME OVER THE EXTREME SRN PENINSULA MONDAY NIGHT/
TUES...BUT MUCH OF W-CENTRAL FL SHOULD REMAIN MOIST WITH ABV CLIMO
POPS CONTG. AS FOR TEMPS BLEND OF FAN/FWC NUMBERS LOOKS GOOD WITH
TEMPS IN THE MID TO UPR 80S FROM CONTG N TO S.

MCMICHAEL

In the hours before

Special weather statement, Sep 20, 11:28 AM EDT, 4 hours 26 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, 4 hours 26 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, 1:47 PM EDTFlash Flood WarningTBWHillsborough2 hr

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.