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?