SYNOPTIC METEOROLOGY LABORATORYSYNOPTIC METEOROLOGY LABORATORY

The Dallas and Fort WorthThe Dallas and Fort Worth Storms of May 5, 1995Storms of May 5, 1995

BY: Brent Crisp, Phil Grigsby, Thomas Jones, Devon Lucie,BY: Brent Crisp, Phil Grigsby, Thomas Jones, Devon Lucie, Tim Love, Andrew Reader, and Matt SattlerTim Love, Andrew Reader, and Matt Sattler

Presentation OutlinePresentation Outline

Synoptic OverviewSynoptic Overview- Satellite imagery- Satellite imagery- Upper air maps- Upper air maps- Soundings- Soundings- Composite Map- Composite Map

Radar SummaryRadar Summary- Reflectivity Products - Reflectivity Products and cross sectionsand cross sections- Velocity Products- Velocity Products and cross sectionsand cross sections- VIL Products- VIL Products- Hail Trends- Hail Trends- Total Precip. Products- Total Precip. Products

Mesoscale SummaryMesoscale Summary- Surface analysis- Surface analysis - 850 mb features- 850 mb features- Shear analysis- Shear analysis- Radar products- Radar products- Storm Wrap-up- Storm Wrap-up

Synoptic Overview of theSynoptic Overview of the

Dallas and Fort WorthDallas and Fort Worth

Storms of May 5, 1995Storms of May 5, 1995

Water Vapor Loop: May 5 1815Z to May 6 0615ZWater Vapor Loop: May 5 1815Z to May 6 0615Z

Dallas/Ft WorthDallas/Ft WorthAreaArea

Visible Satellite Loop: May 5 1815Z to May 5 2302ZVisible Satellite Loop: May 5 1815Z to May 5 2302Z

250 mb Heights and Observations250 mb Heights and Observations

250 mb Heights and Observations250 mb Heights and Observations

• • Diffluent FlowDiffluent Flow Over the Southern Plains Over the Southern Plains

500 mb Heights and Observations500 mb Heights and Observations

500 mb Heights and Observations500 mb Heights and Observations

500 mb Shortwave500 mb Shortwave

500 mb Vorticity Contours500 mb Vorticity Contours

Weak Vort MaxWeak Vort Max12 s^-112 s^-1

850 mb Heights and Observations850 mb Heights and Observations

850 mb Heights and Observations850 mb Heights and Observations

Strong Flow from the Gulf, Bringing in Moistureat 850mb

850 mb Dew point Temperatures850 mb Dew point Temperatures

10°-16°C Dew Points10°-16°C Dew Pointsat 850mbat 850mb

5:00 p.m. Surface Analysis5:00 p.m. Surface Analysis

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Soundings from DFWSoundings from DFW

12Z May 512Z May 5 00Z May 600Z May 6

Lifted Indices at 00Z May 6Lifted Indices at 00Z May 6

Precipitable Water at 00Z May 6Precipitable Water at 00Z May 6

Composite MapComposite Map

• • 250 mb diffluent 250 mb diffluent flowflow

Composite MapComposite Map

• • 250 mb diffluent 250 mb diffluent flowflow

• • 500 mb shortwave500 mb shortwave

Composite MapComposite Map

• • 250 mb diffluent 250 mb diffluent flowflow

• • 500 mb shortwave500 mb shortwave

• • 850 mb dew point850 mb dew point temperatures 10° -temperatures 10° - 16° C16° C

Composite MapComposite Map

• • 250 mb diffluent 250 mb diffluent flowflow

• • 500 mb shortwave500 mb shortwave

• • 850 mb dew point850 mb dew point temperaturestemperatures

• • low-level jet low-level jet

Composite MapComposite Map

• • 250 mb diffluent 250 mb diffluent flowflow

• • 500 mb shortwave500 mb shortwave

• • 850 mb dew point850 mb dew point temperaturestemperatures

• • low-level jetlow-level jet

• • stationary frontstationary front

Composite MapComposite Map

• • 250 mb diffluent 250 mb diffluent flowflow

• • 500 mb shortwave500 mb shortwave

• • 850 mb dew point850 mb dew point temperaturestemperatures

• • low-level jetlow-level jet

• • stationary frontstationary front

• • precipitable waterprecipitable water values from 1.5-2.0values from 1.5-2.0 inchesinches

Radar Summary of theRadar Summary of the

Dallas and Fort WorthDallas and Fort Worth

Storms of May 5, 1995Storms of May 5, 1995

Base Reflectivity Loop from 6:04 p.m. to 8:59 p.m.Base Reflectivity Loop from 6:04 p.m. to 8:59 p.m.

Dallas Co.Dallas Co.Tarrant Co.Tarrant Co.Parker Co.Parker Co.

Base Velocity Loop from 6:04 p.m. to 8:59 p.m.Base Velocity Loop from 6:04 p.m. to 8:59 p.m.

• • 6:00 p.m DFW RADAR6:00 p.m DFW RADAR

• • Supercell located in SW Supercell located in SW Parker CountyParker County

• • Squall line extends fromSquall line extends from Young to Eastern CountyYoung to Eastern County

• • Reflectivity max at Reflectivity max at 60 dBz’s60 dBz’s

Base Reflectivity Cross SectionBase Reflectivity Cross Section

• • 6:00 p.m. DFW6:00 p.m. DFW radarradar

• • South to North South to North cross sectioncross section

• • Bounded Weak Bounded Weak Echo RegionEcho Region

• • Hail CoreHail Core

• • Reflectivity max at Reflectivity max at 60 dBz’s60 dBz’s

6:00 p.m. VIL Product from DFW6:00 p.m. VIL Product from DFW

• • Max VIL Max VIL 70-75 Kg/m^2 70-75 Kg/m^2

Location of Location of SupercellSupercell

• • 6:45 p.m. DFW radar6:45 p.m. DFW radar

• • Supercell located in SE Supercell located in SE Parker County about to Parker County about to enter FTW metroenter FTW metro

• • Squall line beginning toSquall line beginning to bow west of the bow west of the supercellsupercell

• • Max Reflectivity ofMax Reflectivity of 75 dBz’s75 dBz’s

Base Reflectivity Cross SectionBase Reflectivity Cross Section

• • 6:45 p.m. DFW6:45 p.m. DFW radarradar

• • South to NorthSouth to North cross sectioncross section

• • More pronouncedMore pronounced Bounded Weak Bounded Weak Echo RegionEcho Region

• • Hail CoreHail Core

• • Reflectivity max at Reflectivity max at 75 dBz’s75 dBz’s

• • Max VIL Max VIL 60-65 Kg/m^2 60-65 Kg/m^2

6:45 p.m. VIL Product from DFW6:45 p.m. VIL Product from DFW

• • 6:45 p.m. DFW6:45 p.m. DFW radarradar

• • Base Velocity Base Velocity productproduct

• • Strongest mesoStrongest meso WNW of radar siteWNW of radar site

strong mesostrong meso

Base Velocity Cross SectionBase Velocity Cross Section

• • 6:45 p.m. DFW6:45 p.m. DFW radarradar

• • West to EastWest to East cross sectioncross section

• • Meso evidentMeso evident within the Super-within the Super- cellcell

• • Isentropic liftIsentropic lift

• • Hail and severe hailHail and severe hail probabilities at 100 %probabilities at 100 %

• • Max hail size constant atMax hail size constant at 3+ inches 3+ inches • • Slightly decreasing VIL Slightly decreasing VIL valuesvalues

6:00 p.m. - 6:45 p.m. Hail Trends6:00 p.m. - 6:45 p.m. Hail Trends

• • 7:30 p.m. DFW radar7:30 p.m. DFW radar

• • Supercell located inSupercell located in Tarrant CountyTarrant County

• • Time of largest hail Time of largest hail fallingfalling

• • Supercell is caught bySupercell is caught by the squall linethe squall line

• • Max Reflectivity ofMax Reflectivity of 67 dBz’s67 dBz’s

Base Reflectivity Cross SectionBase Reflectivity Cross Section

• • 7:45 p.m. DFW7:45 p.m. DFW radarradar

• • South to NorthSouth to North cross sectioncross section

• • Hail Core lesseningHail Core lessening

• • Lower dBz’s aloftLower dBz’s aloft

• • Reflectivity max at Reflectivity max at 67 dBz’s67 dBz’s

• • Max VIL Max VIL 45-50 Kg/m^2 45-50 Kg/m^2

7:30 p.m. VIL Product from DFW7:30 p.m. VIL Product from DFW

6:30 p.m. - 7:30 p.m. Hail Trends6:30 p.m. - 7:30 p.m. Hail Trends

• • Hail and severe hailHail and severe hail probabilities rapidly probabilities rapidly decrease after 7:20 p.m.decrease after 7:20 p.m.

• • Max hail size from 3+ Max hail size from 3+ inches to less than an inch.inches to less than an inch.

• • Decreasing VIL valuesDecreasing VIL values

• • 8:00 p.m. DFW radar8:00 p.m. DFW radar

• • Heavy precip threatHeavy precip threat beginningbeginning

• • Supercell is consumedSupercell is consumed by the squall lineby the squall line

• • Large area of reflectivity Large area of reflectivity greater than 50 dBzgreater than 50 dBz

• • 8:00 p.m. DFW8:00 p.m. DFW radarradar

• • West to EastWest to East cross sectioncross section

• • Strong upliftingStrong uplifting within the squall-within the squall- line.line.

Base Velocity Cross SectionBase Velocity Cross Section

One Hour Precip from 8:00 to 9:00 p.m.One Hour Precip from 8:00 to 9:00 p.m.

Approx. 3 inchesApprox. 3 inchesof rain in one hourof rain in one hour

One Hour Precip Loop from 8:04 to 8:50 p.m.One Hour Precip Loop from 8:04 to 8:50 p.m.

Base Reflectivity Cross SectionBase Reflectivity Cross Section

• • 9:00 p.m. DFW9:00 p.m. DFW radarradar

• • South to NorthSouth to North cross sectioncross section

• • Very low dBz’s aloftVery low dBz’s aloft

• • Reflectivity max at Reflectivity max at 55 dBz’s55 dBz’s

• • 9:00 p.m. total precip9:00 p.m. total precip imageimage

• • Areas received overAreas received over 3.5 inches of rain3.5 inches of rain

3.5 + inches 3.5 + inches of rainof rain

Mesoscale Analysis of theMesoscale Analysis of the

Dallas and Fort WorthDallas and Fort Worth

Storms of May 5, 1995Storms of May 5, 1995

5:00 p.m. Surface Analysis5:00 p.m. Surface Analysis

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Inverted TroughInverted Trough

00Z May 6, 850 mb Moisture Transport00Z May 6, 850 mb Moisture Transport

• • 850 mb moisture850 mb moisture

• • Low-level jetLow-level jet

• • MesoHigh over LAMesoHigh over LA

850 mb Theta-E Chart850 mb Theta-E Chart

• • Theta-E bulgeTheta-E bulge

• • Inverted TroughInverted Trough

Base Reflectivity Loop from 6:04 p.m. to 8:59 p.m.Base Reflectivity Loop from 6:04 p.m. to 8:59 p.m.

1000 mb (green) - 700 mb (blue) shear1000 mb (green) - 700 mb (blue) shear2100Z May 52100Z May 5

• • 7:30 p.m radar image 7:30 p.m radar image

• • Time of largest hailTime of largest hail fallingfalling

• • Strong bow in squall lineStrong bow in squall line approaching supercellapproaching supercell

Vertical Wind Profiler, 7:00 - 8:00p.m.Vertical Wind Profiler, 7:00 - 8:00p.m.

Inflow NotchInflow Notch Heavy Heavy RainsRains

9:10 p.m. Reflectivity Image9:10 p.m. Reflectivity Image

STORM DAMAGE SUMMARYSTORM DAMAGE SUMMARY(FOUR PLAYERS CAUSE MAYHEM)(FOUR PLAYERS CAUSE MAYHEM)

• HAIL UP TO 4” IN DIAMETERHAIL UP TO 4” IN DIAMETER

• WIND REPORTS TO 75 MPHWIND REPORTS TO 75 MPH

• HEAVY RAINFALL RATES CAUSE HEAVY RAINFALL RATES CAUSE DEADLY FLASH FLOODINGDEADLY FLASH FLOODING

• LIGHTNING STRIKESLIGHTNING STRIKES

OFFICIAL HAIL DAMAGEOFFICIAL HAIL DAMAGE

• 80+ REPORTS OF 1” OR SMALLER 80+ REPORTS OF 1” OR SMALLER HAILHAIL

• 8 REPORTS OF 2” - 3” HAIL8 REPORTS OF 2” - 3” HAIL

• 3 REPORTS OF 3 REPORTS OF 4” HAIL4” HAIL

• 90 INJURIES ASSOCIATED WITH HAIL90 INJURIES ASSOCIATED WITH HAIL

• DAMAGE TO BUILDINGS.DAMAGE TO BUILDINGS.

FLASH FLOODINGFLASH FLOODING

• LARGEST CONTRIBUTOR TO LARGEST CONTRIBUTOR TO FATALITIESFATALITIES

• 15 MINUTE RAINFALL AMOUNTS 15 MINUTE RAINFALL AMOUNTS VARYING FROM 1.58” TO 2.24” IN VARYING FROM 1.58” TO 2.24” IN DALLAS METRO AREADALLAS METRO AREA

• INSUFFICIENT DRAINAGE FOR INSUFFICIENT DRAINAGE FOR RAINFALL RATERAINFALL RATE

WIND DAMAGEWIND DAMAGE

• SEVERAL REPORTS IN EXCESS OF 70 SEVERAL REPORTS IN EXCESS OF 70 MPHMPH

• WALL OF LOCAL WAREHOUSE WALL OF LOCAL WAREHOUSE BLOWN INBLOWN IN

MAY 5 - 6 FATALITIESMAY 5 - 6 FATALITIES

• 20 DEATHS TOTAL20 DEATHS TOTAL

• 4 FATALITIES FROM VICTIMS DRIVING 4 FATALITIES FROM VICTIMS DRIVING INTO HIGH WATERINTO HIGH WATER

• 2 FATALITIES WHEN ROOF COLLAPSES2 FATALITIES WHEN ROOF COLLAPSES

• 1 VICTIM STRUCK BY LIGHTNING1 VICTIM STRUCK BY LIGHTNING

• 3 VICTIMS PULLED INTO DRAINAGE 3 VICTIMS PULLED INTO DRAINAGE SYSTEMSYSTEM

AN OUNCE OF PREVENTIONAN OUNCE OF PREVENTION

• 60 - 70 OF HAIL INJURIES OCCURRED 60 - 70 OF HAIL INJURIES OCCURRED AT MAYFESTAT MAYFEST

• MAYFEST OFFICIALS DID NOT MAYFEST OFFICIALS DID NOT CONTACT NWS FOR WEATHER CONTACT NWS FOR WEATHER REPORT PRIOR TO EVENTREPORT PRIOR TO EVENT

• ““WARNINGS WERE ISSUED NEARLY WARNINGS WERE ISSUED NEARLY 25 TO 30 MINUTES” PRIOR TO STORM 25 TO 30 MINUTES” PRIOR TO STORM HITTING MAYFESTHITTING MAYFEST

Questions?Questions?

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