Life-Cycle ofTropical Storm Erin (2007)

Thomas J. Galarneau, Jr., and Lance F. Bosart

University at Albany, State University of New York

Albany, NY

*with contributions from Roger Edwards, SPC

9th Annual Northeast Regional Operational Workshop

8 November 2007

Motivation

• Widespread post-landfall rainfall and wind associated with Tropical Storm (TS) Erin during 16–23 August 2007

Goals

• Overview large-scale environment

• Examine aspects of TS Erin life-cycle in more detail:– Incipient development to landfall along TX coast– Widespread TX rains/reintensification over OK– “PRE” over WI– KY rains and VA/NC MCS

Goals

• Overview large-scale environment

• Examine aspects of TS Erin life-cycle in more detail:– Incipient development to landfall along TX coast– Widespread TX rains/reintensification over OK– “PRE” over WI– KY rains and VA/NC MCS

Data Sources

• 2.5 NCEP–NCAR Reanalysis from ESRL

• 1.0 NCEP–GFS final analysis from NCAR

• Soundings from University of Wyoming

• Standard surface data from UAlbany

• OK Mesonet data from OK Climo Survey

• Radar imagery from NCAR and SPC

• Precipitation analyses from NPVU

• Trajectories from NOAA HYSPLIT model

250 hPa (dam) mean and anomaly and vector wind (standard barbs) mean9–23 August 2007

2.5 NCEP–NCAR Reanalysis

13

23

2119

17

15

Erin track

250 hPa (dam) mean and anomaly and vector wind (standard barbs) mean9–23 August 2007

2.5 NCEP–NCAR Reanalysis

13

23

2119

17

15landfall06Z/16

reintensification00–06Z/19

PRE00–12Z/19

MCS21Z/21–06Z/22

intense rains06Z/21–18Z/21

intense rains12Z/16–18Z/18

350

355

360

365

370

00Z/13 00Z/14 00Z/15 00Z/16 00Z/17 00Z/18 00Z/19 00Z/20 00Z/21 00Z/22 00Z/23

Time/Date (UTC)

DT Theta (K)

5

10

15

20

25

850-DT Shear (m/s) and CI (K)

DT THETA 850-DT SHEAR CI

landfall

reintensificationover Oklahoma, and

Wisconsin PRE

North Carolina/VirginiaMCSKentucky rains

1.0 GFS Final Analyses

Azimuth average of DT (K), 850 hPa–DT wind shear (m s1), and CI (K)

DT

(

K)

850–

DT

sh

ear

(m s

1)

and

CI

(K)

Time/Date (UTC)

€

CI =θ(@DT) −θe (@850hPa)

Incipient development–landfall0000 UTC 8–1200 UTC 16 Aug 2007

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 7 August 2007

1.0 NCEP–GFS Analyses

x

L=“Erin”X=DT disturbance

=DT trough

1200 UTC 8 August 2007

1.0 NCEP–GFS Analyses

x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 9 August 2007

1.0 NCEP–GFS Analyses

x x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 10 August 2007

1.0 NCEP–GFS Analyses

xx x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 11 August 2007

1.0 NCEP–GFS Analyses

x x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 12 August 2007

1.0 NCEP–GFS Analyses

x x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 13 August 2007

1.0 NCEP–GFS Analyses

x x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 14 August 2007

1.0 NCEP–GFS Analyses

x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 15 August 2007

1.0 NCEP–GFS Analyses

xx x

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 16 August 2007

1.0 NCEP–GFS Analyses

xxx

L=“Erin”X=DT disturbance

=DT trough

L

DT (K), 850–DT shear (knots), and 925–850 hPa (10-4 s-1)

TX rains andOK reintensification

0000 UTC 17–0000 UTC 20 Aug 2007

DT (K) and vector wind (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 17 August 2007 1.0 NCEP–GFS Analyses

Erin

Source: NPVU

DT (K) and vector wind (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 18 August 2007 1.0 NCEP–GFS Analyses

Erin

Source: NPVU

DT (K) and vector wind (knots), and 925–850 hPa (10-4 s-1)

1200 UTC 19 August 2007 1.0 NCEP–GFS Analyses

Erin

Source: NPVU

Source: NCAR image archive

12Z/16

Source: NCAR image archive

18Z/16

Source: NCAR image archive

00Z/17

Source: NCAR image archive

00Z/17

FWD

DRT

1000 J kg-1

200 J kg-1

Source: NCAR image archive

06Z/17

Source: NCAR image archive

12Z/17

Source: NCAR image archive

18Z/17

Source: NCAR image archive

00Z/18

Source: NCAR image archive

00Z/18

FWD

MAF

1800 J kg-1

130 J kg-1

00Z/18

Source: NCAR image archive

06Z/18

Source: NCAR image archive

12Z/18

Source: NCAR image archive

18Z/18

Source: NCAR image archive

00Z/19

Source: NCAR image archive

00Z/19

FWD

1300 J kg-1

OUN

1800 J kg-1

Source: NCAR image archive

06Z/19

Source: NCAR image archive

12Z/19

€

∇Surface and12Z/19

L

Erin

barocliniczone

X

(105 s1), (K), and vector wind (knots)

Source: Roger Edwards, NOAA/NWS/SPC

0400–1300 UTC 19 August 2007

BREF and OK Mesonet Observations

Source: Roger Edwards,NOAA/NWS/SPC

0500–1300Z/19

LL

Wisconsin “PRE”0000–1200 UTC 19 August

Erin

PRE

06Z/19

Source: NCAR image archive

Erin

PREbarocliniczone

L

€

∇Surface and06Z/19

Source: NPVU

24 h Total Precipitation (in.) ending 12Z/19

Erin

PRE

Source: NPVU

24 h Total Precipitation (in.) ending 12Z/19

Erin

PRE

OAX12Z/19

SGF00Z/19

700 (dam), 1000–500 , 850–500 wind (knots), and Precipitable Water (mm)

1200 UTC 16 August 2007 1.0 NCEP–GFS Analyses

L

700 (dam), 1000–500 , 850–500 wind (knots), and Precipitable Water (mm)

1200 UTC 17 August 2007 1.0 NCEP–GFS Analyses

L

700 (dam), 1000–500 , 850–500 wind (knots), and Precipitable Water (mm)

1200 UTC 18 August 2007 1.0 NCEP–GFS Analyses

L

700 (dam), 1000–500 , 850–500 wind (knots), and Precipitable Water (mm)

1200 UTC 19 August 2007 1.0 NCEP–GFS Analyses

L

Summary

• Pre-landfall key points:– Disturbance possibly originated from convection

over South American continent at 00Z/8– Upper-level disturbance on DT inhibited

intensification of pre-TS Erin prior to 15 August– Erin became minimal TS on 15 August just prior

to landfall (at 06Z/16)

Summary

• Erin moved around periphery of continental anticyclone during 16–23 August

• Post-landfall key points:– Produced 4–8” rains over TX 12Z/16–00Z/19– Reintensified to TS strength over OK 00–12Z/19– Contributed tropical moisture to WI PRE 00–12Z/19– Generated 2–4” rains over KY 12–18Z/21– Triggered severe MCS over VA/NC 18Z/21–00Z/22

Concluding Remarks

• Link between continental MCVs and TS ErinTS Erin at 12Z/19 Mature MCV at 18Z/11 June 2003

(105 s1), (K), vector wind (knots)

Concluding Remarks

• Possible physical mechanism for reintensification

• Intense cyclonic vorticity maxima develop beneath convective towers.• These cyclonic vorticity maxima wrap into “main” cyclonic circulation.(e.g., Montgomery and Enagonio (1998); Hendricks et al. (2004); Conzemius et al. (2007)

= cyclonic vorticity maxima

09Z/19 12Z/19