Multiscale Analyses of Tropical Cyclone-Midlatitude Jet Interactions: Camille (1969) and Danny (1997) Matthew S. Potter, Lance F. Bosart, and Daniel Keyser Department of Atmospheric and Environmental Sciences University at Albany, SUNY, Albany, NY Support Provided By UCAR/NCEP Grant S th Annual Northeastern Storm Conference Saturday 3 March 2012

Presentation Outline Motivation and Objectives Data and Methodology TC Camille (1969) Multiscale Analysis TC Danny (1997) Multiscale Analysis Concluding Remarks

Motivation Interactions between over land tropical cyclones and midlatitude jets are not fully understood Severe inland flooding associated with TC Camille has not been given as much attention as other events: – Agnes (1972) – Fran (1996) – Floyd (1999) Documentation of an inland reintensifying TC, such as TC Danny, is scarce

Objectives Document the synoptic background and underlying mesoscale processes that led to: – the inland flooding associated with TC Camille – the inland reintensification of TC Danny Compare and contrast the two events

Data and Methodology Maps and cross sections were constructed using reanalysis datasets: – 1.125° ERA-40 (TC Camille) – 0.5° Climate Forecast System Reanalysis (CFSR) (TC Danny)

Data and Methodology Radar data – Hourly radar summary charts are used in the Camille case study to track the evolution of the precipitation over west-central Virginia – WSR-88D radar datasets are used to identify structural changes in the convective and stratiform precipitation as Danny reintensified A potential vorticity (PV) perspective is used to interpret the multiscale analyses

TC Camille (1969) Overview 0000 UTC Locations 0000 UTC 18 August 909 hPa 165 kt 0000 UTC 20 August 1005 hPa 25 kt Severe Inland Flooding (153 fatalities) 690 mm (27 in) of rain fell over West Central Nelson County The Roanoke Times

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Camille (1969) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Camille (1969) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Camille (1969) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Camille (1969) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Camille (1969) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Camille (1969) Overview

Precipitable water (mm), 700-hPa Omega (light blue contour every -2 × hPa s -1 ), 925-hPa heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt) Moisture Transport Southerly winds

Precipitable water (mm), 700-hPa Omega (light blue contour every -2 × hPa s -1 ), 925-hPa heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt) Moisture Transport Baroclinic zone

Precipitable water (mm), 700-hPa Omega (light blue contour every -2 × hPa s -1 ), 925-hPa heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt) Moisture Transport Nearly 60 mm of PW

Moisture Transport Precipitable water (mm), 700-hPa Omega (light blue contour every -2 × hPa s -1 ), 925-hPa heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt) Upward vertical motion

Moisture Transport Precipitable water (mm), 700-hPa Omega (light blue contour every -2 × hPa s -1 ), 925-hPa heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt) Upward vertical motion Nearly 60 mm of PW Baroclinic zone Southerly winds

Moisture Transport Precipitable water (mm), 700-hPa Omega (light blue contour every -2 × hPa s -1 ), 925-hPa heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt) Favorable conditions for inland flooding

Radar Summary Charts 2345 UTC 19 August 0445 UTC 20 August Scattered thunderstorms associated with the frontal boundary started to affect northern Virginia around 0000 UTC 20 August Thunderstorms became more numerous around 0600 UTC 20 August as TC Camille entered the region Adapted from NCDC (National Climatic Data Center) radar summary charts 75° 80° 35° 40° TRW RW UTC 19 August 75° 80° 35° 40° TRW TRW+ TRW 40,000 ft echo tops

Thunderstorms moved east of west-central Virginia around 1000 UTC 20 August Radar Summary Charts 0945 UTC 20 August 2345 UTC 19 August 75° 80° 35° 40° RW TRW+ RW- Adapted from NCDC (National Climatic Data Center) radar summary charts

Frontogenesis (shaded in K (100 km) -1 (3 h) -1 ), θ (solid black every 5 K), ω (dotted red every -2 × hPa s -1, negative values only), winds normal to the cross section (m s -1 ) and the ageostrophic wind component tangential to the cross section (m s -1 ) Ageostrophic Circulation and Frontogenesis Upper-level jet Approximate location of hardest hit area Divergent ageostrophic winds 5 cm/s

Frontogenesis (shaded in K (100 km) -1 (3 h) -1 ), θ (solid black every 5 K), ω (dotted red every -2 × hPa s -1, negative values only), winds normal to the cross section (m s -1 ) and the ageostrophic wind component tangential to the cross section (m s -1 ) Ageostrophic Circulation and Frontogenesis Lower-tropospheric frontogenesis 5 cm/s

Ageostrophic Circulation and Frontogenesis 5 cm/s Frontogenesis (shaded in K (100 km) -1 (3 h) -1 ), θ (solid black every 5 K), ω (dotted red every -2 × hPa s -1, negative values only), winds normal to the cross section (m s -1 ) and the ageostrophic wind component tangential to the cross section (m s -1 ) Tropospheric-deep ascent

Camille Remarks The severe inland flooding associated with TC Camille can be attributed to: (1)Tropospheric-deep ascent beneath the equatorward entrance region of a downstream 45 m s −1 upper- level jet (2) Moist, lower-level southerly flow that ascended over the lower-tropospheric baroclinic zone (3) Frontogenesis and mesoscale ascent associated with the surface and lower-tropospheric baroclinic zone (4) Heavy upslope precipitation in the mountains

TC Danny (1997) Overview 0000 UTC Locations 1800 UTC 24 July 1000 hPa 40 kt 0000 UTC 19 July 984 hPa 70 kt 0000 UTC 24 July 1012 hPa 20 kt 960 mm of rain fell over Dauphin Island Track where TC Danny reintensified inland

TC Danny (1997) Overview 250-hPa wind speed (shaded, m s -1 ), 1000 – 500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)

TC Danny (1997) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Danny (1997) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Danny (1997) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Danny (1997) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)

TC Danny (1997) Overview

250-hPa wind speed (shaded, m s -1 ), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa) TC Danny (1997) Overview

Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s -1 ) Potential temperature (shaded every 5 K), 850 – 200-hPa shear (barbs in kt), and 925 – 850-hPa layer- averaged relative vorticity (solid black every 1.0 × s -1 ) Relatively Low Shear Environment

Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s -1 ) Potential temperature (shaded every 5 K), 850 – 200-hPa shear (barbs in kt), and 925 – 850-hPa layer- averaged relative vorticity (solid black every 1.0 × s -1 ) Strengthening PV Tower

Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s -1 ) Potential temperature (shaded every 5 K), 850 – 200-hPa shear (barbs in kt), and 925 – 850-hPa layer- averaged relative vorticity (solid black every 1.0 × s -1 ) Strengthening PV Tower Amplifying PV Trough

Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s -1 ) Potential temperature (shaded every 5 K), 850 – 200-hPa shear (barbs in kt), and 925 – 850-hPa layer- averaged relative vorticity (solid black every 1.0 × s -1 ) Strengthening PV Tower Increase in lower-tropospheric vorticity Amplifying PV Trough

Cross Section and Dynamic Tropopause Map PV (shaded every 1 PVU), θ (solid black, every 5 K), and the wind component normal to the cross section (dotted green every 5 m s -1 ) Potential temperature (shaded every 5 K), 850 – 200-hPa shear (barbs in kt), and 925 – 850-hPa layer- averaged relative vorticity (solid black every 1.0 × s -1 ) Strengthening PV Tower Amplifying PV Trough Increase in lower-tropospheric vorticity

KBMX Base Reflectivity 0013 UTC 23 July GOES-8 Visible Image 2315 UTC 22 July Radar and Satellite Imagery

KFFC Base Reflectivity 1218 UTC 23 July GOES-8 Visible Image 1215 UTC 23 July Radar and Satellite Imagery

KGSP Base Reflectivity 0015 UTC 24 July GOES-8 Visible Image 2315 UTC 23 July Radar and Satellite Imagery

KAKQ Base Reflectivity 1318 UTC 24 July Radar and Satellite Imagery GOES-8 Visible Image 1313 UTC 24 July

GOES-8 Visible Image 1815 UTC 24 July KAKQ Base Reflectivity 1814 UTC 24 July Radar and Satellite Imagery

Role of Diabatic Heating Convection concentrated around TC Danny led to an increase of diabatic heating at mid-levels PV production at low-levels, suggested by the plot, contributed to TC Danny’s inland reintensification Valid at:

Role of Diabatic Heating (0600 UTC 24 July) 250-hPa wind speed (color shading in kt), 250-hPa potential vorticity (solid gray every 1 PVU), 250-hPa relative humidity (gray shading in %), 600 – 400-hPa layer-averaged ω (red every 5 × hPa s -1, negative values only), 300–200-hPa layer-averaged irrotational wind (arrows, m s -1 ) Diabatic outflow from convection around TC Danny strengthens jet

Role of Diabatic Heating (1200 UTC 24 July) 250-hPa wind speed (color shading in kt), 250-hPa potential vorticity (solid gray every 1 PVU), 250-hPa relative humidity (gray shading in %), 600 – 400-hPa layer-averaged ω (red every 5 × hPa s -1, negative values only), 300–200-hPa layer-averaged irrotational wind (arrows, m s -1 ) Diabatic outflow from convection around TC Danny strengthens jet

Role of Diabatic Heating (1800 UTC 24 July) 250-hPa wind speed (color shading in kt), 250-hPa potential vorticity (solid gray every 1 PVU), 250-hPa relative humidity (gray shading in %), 600 – 400-hPa layer-averaged ω (red every 5 × hPa s -1, negative values only), 300–200-hPa layer-averaged irrotational wind (arrows, m s -1 ) Diabatic outflow from convection around TC Danny strengthens jet

Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km) -1 (3 h) -1 ), θ (solid black every 5 K), ω (dotted red every - -4 × hPa s -1 ), wind component normal to the cross section (solid brown, m s -1 ), and the ageostrophic wind component tangential to the cross section (arrows, m s -1 ) 5 cm/s Upper-level jet Approximate Location of TC Danny Divergent ageostrophic winds

Lower-tropospheric Frontogenesis Ageostrophic Circulation and Frontogenesis Frontogenesis (shaded in K (100 km) -1 (3 h) -1 ), θ (solid black every 5 K), ω (dotted red every - -4 × hPa s -1 ), wind component normal to the cross section (solid brown, m s -1 ), and the ageostrophic wind component tangential to the cross section (arrows, m s -1 ) 5 cm/s

Ageostrophic Circulation and Frontogenesis 5 cm/s Frontogenesis (shaded in K (100 km) -1 (3 h) -1 ), θ (solid black every 5 K), ω (dotted red every - -4 × hPa s -1 ), wind component normal to the cross section (solid brown, m s -1 ), and the ageostrophic wind component tangential to the cross section (arrows, m s -1 ) Tropospheric-deep ascent

Danny Remarks The inland reintensification of TC Danny can be attributed to (1)Frontogenesis along a lower-tropospheric baroclinic zone and associated tropospheric-deep ascent beneath the equatorward entrance region of a 35 m s −1 upper-level jet (2)Deep convection that provided a source of diabatic heating that reinforced the ascent near the storm center and increased lower-tropospheric PV (3)Negative PV advection by the diabatically driven upper- level outflow that acted to strengthen the downstream meridional PV gradient and associated jet

Concluding Remarks A downstream midlatitude jet, which provided tropospheric deep ascent, was evident in the TC Camille and TC Danny cases Lower-tropospheric frontogenesis, which also provided additional ascent, was evident in both cases Midlatitude jet and lower-tropospheric baroclinic zone associated with TC Camille were stronger Synoptic features associated with TC Danny were weaker; however, the TC was able to reintensify over land

Concluding Remarks So why did TC Danny reintensify, while TC Camille did not? – Internal dynamics (i.e., focused diabatic heating), which allowed for TC Danny to strengthen as a result of PV production at low levels – Weaker shear around TC Danny prior to reintensification, which created a favorable environment for organized convection Further analysis, via numerical modeling, is needed to answer this question

Thank You! Questions?