Multiscale Analyses of Tropical Cyclone-Midlatitude
Jet Interactions: Camille (1969) and Danny (1997)
Matthew S. Potter, Lance F. Bosart, and Daniel KeyserDepartment of Atmospheric and Environmental Sciences
University at Albany, SUNY, Albany, NY
Support Provided By UCAR/NCEP Grant S1071092
37th Annual Northeastern Storm ConferenceSaturday 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 August909 hPa 165 kt
0000 UTC 20 August1005 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 × 10-3 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 × 10-3 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 × 10-3 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 TransportPrecipitable water (mm), 700-hPa Omega (light blue contour every -2 × 10-3 hPa s-1), 925-hPa
heights (contoured in black), θ (dashed red every 2 K), and winds (barbs, kt)
Upward vertical motion
Moisture TransportPrecipitable water (mm), 700-hPa Omega (light blue contour every -2 × 10-3 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 TransportPrecipitable water (mm), 700-hPa Omega (light blue contour every -2 × 10-3 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°
TRWTRW
TRW TRW
RW-
2345 UTC 19 August
2345 UTC 19 August
75°80°
35°
40°
TRW
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 × 10-3 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 × 10-3 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 × 10-3 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 July1000 hPa 40 kt
0000 UTC 19 July984 hPa 70 kt
0000 UTC 24 July1012 hPa 20 kt
960 mm of rain fell over Dauphin Island
Track where TC Danny reintensified inland
TC Danny (1997) Overview250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
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
TC Danny (1997) Overview250-hPa wind speed (shaded, m s-1), 1000–500-hPa thickness (dashed red, dam), and MSLP (solid black, hPa)
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 MapPV (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 × 10-4 s-1)
Relatively Low Shear Environment
Cross Section and Dynamic Tropopause MapPV (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 × 10-4 s-1)
Strengthening PV Tower
Cross Section and Dynamic Tropopause MapPV (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 × 10-4 s-1)
Strengthening PV Tower
Amplifying PV Trough
Cross Section and Dynamic Tropopause MapPV (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 × 10-4 s-1)
Strengthening PV Tower
Increase in lower-tropospheric vorticity
Amplifying PV Trough
Cross Section and Dynamic Tropopause MapPV (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 × 10-4 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 ImageryGOES-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
-25.0 -20.0 -15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 20.0 25.0 30.0
100
200
300
400
500
600
700
800
900
1000
CFSR 6-h Forecasts of Diabatic Heating Calcu-lated from a 3° × 3° Box around TC Danny
23/0023/1224/0024/12
Diabatic Heating (K day-1)
Pres
sure
(hPa
)
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 × 10-3 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 × 10-3 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 × 10-3 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 FrontogenesisFrontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --4 × 10-3 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 FrontogenesisFrontogenesis (shaded in K (100 km)-1 (3 h)-1), θ (solid black every 5 K), ω (dotted red every --4 × 10-3 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 × 10-3 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?