1. SYNOPTIC METEOROLOGY LABORATORY The Dallas and Fort Worth Storms of May 5, 1995 Storms of May 5, 1995 BY: Brent Crisp, Phil Grigsby, Thomas Jones, Devon Lucie, Tim Love, Andrew Reader, and Matt Sattler Tim Love, Andrew Reader, and Matt Sattler

2. Presentation Outline Synoptic Overview - Satellite imagery - Upper air maps - Soundings - Composite Map Radar Summary - Reflectivity Products and cross sections and cross sections - Velocity Products and cross sections and cross sections - VIL Products - Hail Trends - Total Precip. Products Mesoscale Summary - Surface analysis - 850 mb features - Shear analysis - Radar products - Storm Wrap-up

3. Synoptic Overview of the Dallas and Fort Worth Dallas and Fort Worth Storms of May 5, 1995

4. Water Vapor Loop: May 5 1815Z to May 6 0615Z Dallas/Ft Worth Area

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

6. 250 mb Heights and Observations

7. Diffluent Flow Over the Southern Plains Diffluent Flow Over the Southern Plains

8. 500 mb Heights and Observations

9. 500 mb Shortwave

10. 500 mb Vorticity Contours Weak Vort Max 12 s^-1

11. 850 mb Heights and Observations

12. Strong Flow from the Gulf, Bringing in Moisture at 850mb

13. 850 mb Dew point Temperatures 10°-16°C Dew Points at 850mb

14. 5:00 p.m. Surface Analysis L

15. Soundings from DFW 12Z May 5 00Z May 6

16. Lifted Indices at 00Z May 6

17. Precipitable Water at 00Z May 6

18. Composite Map 250 mb diffluent 250 mb diffluent flow flow

19. Composite Map 250 mb diffluent 250 mb diffluent flow flow 500 mb shortwave 500 mb shortwave

20. Composite Map 250 mb diffluent 250 mb diffluent flow flow 500 mb shortwave 500 mb shortwave 850 mb dew point 850 mb dew point temperatures 10° - temperatures 10° - 16° C 16° C

21. Composite Map 250 mb diffluent 250 mb diffluent flow flow 500 mb shortwave 500 mb shortwave 850 mb dew point 850 mb dew point temperatures temperatures low-level jet low-level jet

22. Composite Map 250 mb diffluent 250 mb diffluent flow flow 500 mb shortwave 500 mb shortwave 850 mb dew point 850 mb dew point temperatures temperatures low-level jet low-level jet stationary front stationary front

23. Composite Map 250 mb diffluent 250 mb diffluent flow flow 500 mb shortwave 500 mb shortwave 850 mb dew point 850 mb dew point temperatures temperatures low-level jet low-level jet stationary front stationary front precipitable water precipitable water values from 1.5-2.0 values from 1.5-2.0 inches inches

24. Radar Summary of the Dallas and Fort Worth Storms of May 5, 1995

25. Base Reflectivity Loop from 6:04 p.m. to 8:59 p.m. Dallas Co. Tarrant Co. Parker Co.

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

27. 6:00 p.m DFW RADAR 6:00 p.m DFW RADAR Supercell located in SW Supercell located in SW Parker County Parker County Squall line extends from Squall line extends from Young to Eastern County Young to Eastern County Reflectivity max at Reflectivity max at 60 dBz’s 60 dBz’s

28. Base Reflectivity Cross Section 6:00 p.m. DFW 6:00 p.m. DFW radar radar South to North South to North cross section cross section Bounded Weak Bounded Weak Echo Region Echo Region Hail Core Hail Core Reflectivity max at Reflectivity max at 60 dBz’s 60 dBz’s

29. 6:00 p.m. VIL Product from DFW Max VIL Max VIL 70-75 Kg/m^2 Location of Supercell

30. 6:45 p.m. DFW radar 6:45 p.m. DFW radar Supercell located in SE Supercell located in SE Parker County about to Parker County about to enter FTW metro enter FTW metro Squall line beginning to Squall line beginning to bow west of the bow west of the supercell supercell Max Reflectivity of Max Reflectivity of 75 dBz’s 75 dBz’s

31. Base Reflectivity Cross Section 6:45 p.m. DFW 6:45 p.m. DFW radar radar South to North South to North cross section cross section More pronounced More pronounced Bounded Weak Bounded Weak Echo Region Echo Region Hail Core Hail Core Reflectivity max at Reflectivity max at 75 dBz’s 75 dBz’s

32. Max VIL Max VIL 60-65 Kg/m^2 6:45 p.m. VIL Product from DFW

33. 6:45 p.m. DFW 6:45 p.m. DFW radar radar Base Velocity Base Velocity product product Strongest meso Strongest meso WNW of radar site WNW of radar site strong meso

34. Base Velocity Cross Section 6:45 p.m. DFW 6:45 p.m. DFW radar radar West to East West to East cross section cross section Meso evident Meso evident within the Super- within the Super- cell cell Isentropic lift Isentropic lift

35. Hail and severe hail Hail and severe hail probabilities at 100 % probabilities at 100 % Max hail size constant at Max hail size constant at 3+ inches 3+ inches Slightly decreasing VIL Slightly decreasing VIL values values 6:00 p.m. - 6:45 p.m. Hail Trends

36. 7:30 p.m. DFW radar 7:30 p.m. DFW radar Supercell located in Supercell located in Tarrant County Tarrant County Time of largest hail Time of largest hail falling falling Supercell is caught by Supercell is caught by the squall line the squall line Max Reflectivity of Max Reflectivity of 67 dBz’s 67 dBz’s

37. Base Reflectivity Cross Section 7:45 p.m. DFW 7:45 p.m. DFW radar radar South to North South to North cross section cross section Hail Core lessening Hail Core lessening Lower dBz’s aloft Lower dBz’s aloft Reflectivity max at Reflectivity max at 67 dBz’s 67 dBz’s

38. Max VIL Max VIL 45-50 Kg/m^2 7:30 p.m. VIL Product from DFW

39. 6:30 p.m. - 7:30 p.m. Hail Trends Hail and severe hail Hail 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 values Decreasing VIL values

40. 8:00 p.m. DFW radar 8:00 p.m. DFW radar Heavy precip threat Heavy precip threat beginning beginning Supercell is consumed Supercell is consumed by the squall line by the squall line Large area of reflectivity Large area of reflectivity greater than 50 dBz greater than 50 dBz

41. 8:00 p.m. DFW 8:00 p.m. DFW radar radar West to East West to East cross section cross section Strong uplifting Strong uplifting within the squall- within the squall- line. line. Base Velocity Cross Section

42. One Hour Precip from 8:00 to 9:00 p.m. Approx. 3 inches of rain in one hour

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

44. Base Reflectivity Cross Section 9:00 p.m. DFW 9:00 p.m. DFW radar radar South to North South to North cross section cross section Very low dBz’s aloft Very low dBz’s aloft Reflectivity max at Reflectivity max at 55 dBz’s 55 dBz’s

45. 9:00 p.m. total precip 9:00 p.m. total precip image image Areas received over Areas received over 3.5 inches of rain 3.5 inches of rain 3.5 + inches of rain

46. Mesoscale Analysis of the Dallas and Fort Worth Storms of May 5, 1995

47. 5:00 p.m. Surface Analysis L Inverted Trough

48. 00Z May 6, 850 mb Moisture Transport 850 mb moisture 850 mb moisture Low-level jet Low-level jet MesoHigh over LA MesoHigh over LA

49. 850 mb Theta-E Chart Theta-E bulge Theta-E bulge Inverted Trough Inverted Trough

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

51. 1000 mb (green) - 700 mb (blue) shear 2100Z May 5

52. 7:30 p.m radar image 7:30 p.m radar image Time of largest hail Time of largest hail falling falling Strong bow in squall line Strong bow in squall line approaching supercell approaching supercell

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

54. Inflow Notch HeavyRains

55. 9:10 p.m. Reflectivity Image

56. STORM DAMAGE SUMMARY (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 DEADLY FLASH FLOODINGHEAVY RAINFALL RATES CAUSE DEADLY FLASH FLOODING LIGHTNING STRIKESLIGHTNING STRIKES

57. OFFICIAL HAIL DAMAGE 80+ REPORTS OF 1” OR SMALLER HAIL80+ REPORTS OF 1” OR SMALLER HAIL 8 REPORTS OF 2” - 3” HAIL8 REPORTS OF 2” - 3” HAIL 3 REPORTS OF 4” HAIL3 REPORTS OF 4” HAIL 90 INJURIES ASSOCIATED WITH HAIL90 INJURIES ASSOCIATED WITH HAIL DAMAGE TO BUILDINGS.DAMAGE TO BUILDINGS.

58. FLASH FLOODING LARGEST CONTRIBUTOR TO FATALITIESLARGEST CONTRIBUTOR TO FATALITIES 15 MINUTE RAINFALL AMOUNTS VARYING FROM 1.58” TO 2.24” IN DALLAS METRO AREA15 MINUTE RAINFALL AMOUNTS VARYING FROM 1.58” TO 2.24” IN DALLAS METRO AREA INSUFFICIENT DRAINAGE FOR RAINFALL RATEINSUFFICIENT DRAINAGE FOR RAINFALL RATE

59. WIND DAMAGE SEVERAL REPORTS IN EXCESS OF 70 MPHSEVERAL REPORTS IN EXCESS OF 70 MPH WALL OF LOCAL WAREHOUSE BLOWN INWALL OF LOCAL WAREHOUSE BLOWN IN

60. MAY 5 - 6 FATALITIES 20 DEATHS TOTAL20 DEATHS TOTAL 4 FATALITIES FROM VICTIMS DRIVING INTO HIGH WATER4 FATALITIES FROM VICTIMS DRIVING INTO 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 SYSTEM3 VICTIMS PULLED INTO DRAINAGE SYSTEM

61. AN OUNCE OF PREVENTION 60 - 70 OF HAIL INJURIES OCCURRED AT MAYFEST60 - 70 OF HAIL INJURIES OCCURRED AT MAYFEST MAYFEST OFFICIALS DID NOT CONTACT NWS FOR WEATHER REPORT PRIOR TO EVENTMAYFEST OFFICIALS DID NOT CONTACT NWS FOR WEATHER REPORT PRIOR TO EVENT “WARNINGS WERE ISSUED NEARLY 25 TO 30 MINUTES” PRIOR TO STORM HITTING MAYFEST“WARNINGS WERE ISSUED NEARLY 25 TO 30 MINUTES” PRIOR TO STORM HITTING MAYFEST

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