predecessor rain events ahead of tc ike and tc lowell on 11–14 september 2008 lance f. bosart,...
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Predecessor Rain Events Ahead of TC Ike and TC Lowell on 11–14 September 2008
Lance F. Bosart, Thomas J. Galarneau, Jr., Jason M. Cordeira, and Benjamin J. Moore
Department of Atmospheric and Environmental SciencesUniversity at Albany, SUNY
Albany, NY 12222
11th Annual Northeast Regional Operational WorkshopAlbany, NY
4–5 November 2009
Motivation• Predecessor Rain Events (PREs) are high-impact
weather events that can result in significant inland flooding
• High-impact PREs occurred with TS Erin (18–19 Aug 2007), TC Ike (12–13 Sep 2008), and TC Rita (24–26 Sep 2005)
• PREs represent a big forecast challenge for models and humans alike
• Dynamics and thermodynamics governing PREs need to be better understood
TS Erin PRE 18–19 Aug 2007Example of High-Impact Nature of PREs
Photo from Minneapolis Star Tribune Photo from NWS La Crosse, WI
Outline• Brief synopsis of PRE/TC relationships• Synoptic overview of Lowell/Ike PREs
– Rainfall and satellite signatures– Upper-air analyses– Precipitable water (PW) and sounding analysis
• Regional perspective– Ike moisture, PRE, and downstream jet– Trajectory analysis– Cross section analysis
• Summary
Predecessor Rain Events (PREs)• Coherent area of rain displaced poleward of TC• Moisture transport from TC toward PRE• Event duration ~ 12 h• Maximum rainfall rates typically ≥ 100 mm (24 h)1
• Time lag between PRE and TC passage ~ 36 h
~100
0 km
Bosart and Carr (1978) conceptualmodel of antecedent rainfallfor TC Agnes (1972)
Detailed study of PREs in Cote (2007) andGalarneau et al. (2009, submitted to MWR)
200 hPa h mean (dam) and anomaly (σ), mean wind (kt), and TC tracks
1110
9 8 7
78
910111213
14
15
TC IkeTS Lowell
= 00Z position
8–14 September 2008
Data: 2.5 NCEP–NCAR Reanalysis
72-h Quantitative Precipitation Estimates (inches)
Ending 1200 UTC 14 Sep 2008 http://nmq.ou.edu/
- 1. Lubbock, TX (LBB), 11 Sept, 198.1 mm- broke all-time 24-h rainfall record of 147.8 mm set on 18–19 Oct 1983
- 2. Wichita, KS (ICT), 12 Sept, 261.9 mm- broke all-time 24-h rainfall record of 165.6 mm set on 8 Jun 1923
- 3. Chicago, IL (ORD), 13 Sept, 168.7 mm- broke all-time daily rainfall record of 164.8 mm set on 14 Aug 1987
1
2
3
00Z/13
06Z/13
12Z/13
18Z/13
ORD rainfall in 6-h periods:00–06 UTC 13 5.1 mm06–12 UTC 13 75.4 mm12–18 UTC 13 72.6 mm18–00 UTC 13 19.8 mm
PREPRE
PRE
Ike
IkeIke
Ike
Ike tropical moisturearrives by 06 UTC
L L
LL
WSR-88D base reflectivity mosaic
Source: NCAR case-selection archive
ORD
06Z/14
12Z/14
15Z/14
18Z/14
ORD rainfall in 6-h periods:00–06 UTC 14 1.3 mm06–12 UTC 14 5.6 mm12–18 UTC 14 25.7 mm18–00 UTC 14 5.3 mm
Ike
Ike
Ike
Ike
ORD
WSR-88D base reflectivity mosaic
Source: NCAR case-selection archive
1200 UTC 9 September 2008 1200 UTC 10 September 2008
Infrared Satellite Imagery
source: http://adds.aviationweather.gov
L LI I
L = TC LowellI = TC IKE
1200 UTC 11 September 2008 1200 UTC 12 September 2008
Infrared Satellite Imagery
source: http://adds.aviationweather.gov
LI I
L = TC LowellI = TC IKE
1200 UTC 13 September 2008 1215 UTC 14 September 2008
Infrared Satellite Imagery
source: http://adds.aviationweather.gov
I
I
I = TC IKE
SLP, 1000–500 hPa Thickness, 250 hPa Wind
1200 UTC 8 September 1200 UTC 9 September
SLP (solid contours every 2 hPa), 1000–500 hPa thickness (red dashed contours every 3 dam)and 250 hPa wind speed (shaded in m s−1)
L LI I
I = TC IkeL = TC Lowell
SLP, 1000–500 hPa Thickness, 250 hPa Wind
1200 UTC 10 September 1200 UTC 11 September
SLP (solid contours every 2 hPa), 1000–500 hPa thickness (red dashed contours every 3 dam)and 250 hPa wind speed (shaded in m s−1)
L LI I
I = TC IkeL = TC Lowell
SLP, 1000–500 hPa Thickness, 250 hPa Wind
1200 UTC 12 September 1200 UTC 13 September
SLP (solid contours every 2 hPa), 1000–500 hPa thickness (red dashed contours every 3 dam)and 250 hPa wind speed (shaded in m s−1)
I I
I = TC IkeL = TC Lowell
SLP, 1000–500 hPa Thickness, 250 hPa Wind
0000 UTC 14 September 1200 UTC 14 September
SLP (solid contours every 2 hPa), 1000–500 hPa thickness (red dashed contours every 3 dam)and 250 hPa wind speed (shaded in m s−1)
II
I = TC IkeL = TC Lowell
DT Analysis and Low-Level FrontogenesisDT pressure (shaded in hPa), DT–850 hPa wind shear (barbs in kt),925–850 hPa ζ (contours every 2.0×10−5 s−1)
1200 UTC 12 September 2008
850 hPa h (solid contours every 2 dam)wind (barbs in kt), θ (dashed contours every 2 K),frontogenesis [shaded in K (100 km)−1 (3 h)−1]
II
I = TC Ike
DT Analysis and Low-Level FrontogenesisDT pressure (shaded in hPa), DT–850 hPa wind shear (barbs in kt),925–850 hPa ζ (contours every 2.0×10−5 s−1)
1200 UTC 13 September 2008
850 hPa h (solid contours every 2 dam)wind (barbs in kt), θ (dashed contours every 2 K),frontogenesis [shaded in K (100 km)−1 (3 h)−1]
II
I = TC Ike
DT Analysis and Low-Level FrontogenesisDT pressure (shaded in hPa), DT–850 hPa wind shear (barbs in kt),925–850 hPa ζ (contours every 2.0×10−5 s−1)
1200 UTC 14 September 2008
850 hPa h (solid contours every 2 dam)wind (barbs in kt), θ (dashed contours every 2 K),frontogenesis [shaded in K (100 km)−1 (3 h)−1]
I I
I = TC Ike
1200 UTC 11 Sep 2008
PW (shaded; mm), 250-hPa HGHT (black; dam), 700-hPa WND (kt), and 925–850-hPa REL VOR (magenta;
every 0.5 x 10-4 s-1)
PW above 700 hPa only Total PW
9−10 Sep 11−12 Sep 13−14 Sep
8 24 40 56 7216 32 48 64 80 mm m s−1
Total Precipitable Water Flux [mm m s−1]
Data: 0.5 NCEP–GFS analyses
50 mm m s−1
Source: http://weather.uwyo.edu/upperair/sounding.html
EPZ Santa Teresa DRT Del Rio
MAF Midland
12Z 10 Sep
00Z 11 Sep 12Z 10 Sep
TOP Topeka DVN Davenport
ILX Lincoln
12Z 13 Sep
12Z 12 Sep 12Z 13 Sep
Source: http://weather.uwyo.edu/upperair/sounding.html
1200 UTC 13 September 2008
925 hPa h (dam)925 hPa e (K)
200 hPa wind speed (m s1)
0000 UTC 13 September 2008
250 hPa h (dam), 700 hPa (105 s1)precipitable water (mm), 850–500 hPa mean wind (m s1)
LL
Ike
Ike
PRE
56 mm
56 mm
Data: 0.5 NCEP–GFS analyses
1200 UTC 13 September 2008
700 hPa h (dam), 700 hPa wind (m s1)700 hPa ascent (103 hPa s1)
900–400 hPa relative humidity (%)
925 hPa h (dam), 925 hPa wind (m s1)925 hPa e (K)
200 hPa wind speed (m s1)
Ike Ike
PRE
H H
Data: 0.5 NCEP–GFS analyses
http://www.atmos.albany.edu/student/cordeira/WEB/GFS_ARCHIVE/
Surface Observations and Base Reflectivity (dBZ)
0002 UTC 13 Sep 2008 0600 UTC 13 Sep 2008
NE
SDMN
WI
IL
IA
KSMO
NE
SDMN
WI
IL
IA
KSMO
72-h Backward Air Parcel Trajectories
LBB: 00Z / 12 Sep ICT: 12Z / 12 Sep
hPa10 3020 40 dBZ
Backward trajectories released from latitude and longitude of station every 100 hPaCircles represent 00Z locations
t − 72h position of IKE
t − 72h position of LOWELL
Data: 0.5 NCEP–GFS analyses
72-h Backward Air Parcel Trajectories
TOP: 18Z / 12 Sep CHI: 12Z / 13 Sep
hPa10 3020 40 dBZ
Backward trajectories released from latitude and longitude of station every 100 hPaCircles represent 00Z locations
t − 72h position of IKE
t − 72h position of LOWELL
Data: 0.5 NCEP–GFS analyses
Potential vorticity (PVU), θ (K), wind (kt) Relative humidity (%), θ (K), andupward vertical motion (10−3 hPa s−1)
A
B
A B A B
69
0600 UTC 12 September
Data: 0.5 NCEP–GFS analysesSource: NCAR case-selection archive
Potential vorticity (PVU), θ (K), wind (kt)
A
B
Frontogenesis [K (100 km)−1 (3 h)−1], θ (K), andupward vertical motion (10−3 hPa s−1)
A B A B
69Source:NCAR case-selection archive
1200 UTC 12 September
Data: 0.5 NCEP–GFS analyses
Cross Section Analysis1200 UTC 13 Sep
Potential vorticity (PVU), tangential circulation vectors, potential temperature (K)
PVUC D
C
D
0.5°x0.5° NCEP GFS analysis
Pres
sure
(hPa
)
10 m s−1
10 cm s−1
Cross Section Analysis1200 UTC 14 Sep
Potential vorticity (PVU), tangential circulation vectors, potential temperature (K)
PVUC D
C
D
0.5°x0.5° NCEP GFS analysis
Pres
sure
(hPa
)
10 m s−1
10 cm s−1
Cross Section Analysis1200 UTC 13 Sep
Mixing ratio (g kg−1), wind speed (kts), tangential circulation vectors, potential temperature (K)
g kg−1C Dkts
C
D
0.5°x0.5° NCEP GFS analysis
Pres
sure
(hPa
)
10 m s−1
10 cm s−1
Cross Section Analysis1200 UTC 14 Sep
Mixing ratio (g kg−1), wind speed (kts), tangential circulation vectors, potential temperature (K)
g kg−1C Dkts
C
D
0.5°x0.5° NCEP GFS analysis
Pres
sure
(hPa
)
10 m s−1
10 cm s−1
Cross Section Analysis1200 UTC 13 Sep
K (100 km)−1 (3 h)−1C D
C
D
0.5°x0.5° NCEP GFS analysis
Pres
sure
(hPa
)Petterssen frontogenesis (K (100 km)−1 (3 h)−1), upward vertical
velocity (μb s−1), potential temperature (K)
Cross Section Analysis1200 UTC 14 Sep
Petterssen frontogenesis (K (100 km)−1 (3 h)−1), upward vertical velocity (μb s−1), potential temperature (K)
K (100 km)−1 (3 h)−1C D
C
D
0.5°x0.5° NCEP GFS analysis
Pres
sure
(hPa
)
Summary of TC Ike/Lowell PREs
• PREs fed off deep moisture from Ike and middle- and upper-level moisture from Lowell
• PREs occurred along low-level baroclinic zones well poleward of Ike and Lowell
• PREs were best defined where intense frontogenetical forcing was concentrated
• PREs were driven by deep ascent in equatorward jet-entrance regions
• Downstream jet strengthened considerably due to PRE- and Ike-driven diabatic heating