upper-level mesoscale disturbances on the periphery of closed anticyclones
DESCRIPTION
Upper-level Mesoscale Disturbances on the Periphery of Closed Anticyclones. Thomas J. Galarneau, Jr. and Lance F. Bosart University at Albany, State University of New York Albany, NY 12222 USA. Fourth Symposium on Southwest Hydrometeorology 21 September 2007 – Tucson, AZ. Motivation. - PowerPoint PPT PresentationTRANSCRIPT
Upper-level Mesoscale Upper-level Mesoscale Disturbances on the Periphery of Disturbances on the Periphery of
Closed AnticyclonesClosed Anticyclones
Thomas J. Galarneau, Jr. and Lance F. BosartThomas J. Galarneau, Jr. and Lance F. BosartUniversity at Albany, State University of New YorkUniversity at Albany, State University of New York
Albany, NY 12222 USAAlbany, NY 12222 USA
Fourth Symposium on Southwest Hydrometeorology21 September 2007 – Tucson, AZ
MotivationMotivation Warm season continental closed Warm season continental closed
anticyclones (CAs) link weather and climate anticyclones (CAs) link weather and climate on intraseasonal time scaleson intraseasonal time scales
Can persist for most of 90-day warm seasonCan persist for most of 90-day warm season Surface temperature/rainfall anomalies with Surface temperature/rainfall anomalies with
CAs can determine overall seasonal anomalies CAs can determine overall seasonal anomalies for a given regionfor a given region
High-impact severe weather on CA High-impact severe weather on CA periphery associated with mesoscale periphery associated with mesoscale disturbances disturbances
GoalsGoals
Examine the CA of July 1995 over the Examine the CA of July 1995 over the USUS Impact on rainfall distributionImpact on rainfall distribution Behavior of mesoscale disturbances on Behavior of mesoscale disturbances on
periphery of CA and their role in MCS periphery of CA and their role in MCS developmentdevelopment
Data and MethodsData and Methods
2.52.5 NCEP–NCAR Reanalysis NCEP–NCAR Reanalysis 1.1251.125 ECMWF Reanalysis (ERA-40) ECMWF Reanalysis (ERA-40) 0.250.25 NCEP Unified Precipitation Dataset (UPD) NCEP Unified Precipitation Dataset (UPD) University of Wyoming sounding archiveUniversity of Wyoming sounding archive National Lightning Detection Network (NLDN)National Lightning Detection Network (NLDN) Dynamic tropopause defined at 1.5 PVU surfaceDynamic tropopause defined at 1.5 PVU surface
July 1995 CA over USJuly 1995 CA over US
11-15 Jul 1995 500 hPa HGHT
500 hPa Height (dam) Meanand Anomaly and Wind (m/s)
5–10 July 1995
11–15 July 1995
Height Anomaly
Height Anomaly
Wind
Wind
Fig. A1 from Galarneau et al. 2007
ridge building
eastward progression
2.5 NCEP–NCAR Reanalysis
5
6
78
910
11
12
13 14 15
850 hPa 21C Isotherm Continuity Map0000 UTC 5–15 July 1995
Fig. A5 from Galarneau et al. 20072.5 NCEP–NCAR Reanalysis
00Z/13
DT (K) and wind (knots)
NLDN CG lightning
X
X
X
MCS #1
PV tail
mesoscaledisturbance
1.125 ECMWF Reanalysis
+/-
12Z/13
DT (K) and wind (knots)
X
MCS #1
PV tail
mesoscaledisturbance
X
X
XX
X
X
X
X
1.125 ECMWF Reanalysis
+/-
NLDN CG lightning
00Z/14
DT (K) and wind (knots)
X
MCS #1
PV tail
mesoscaledisturbance
X
X
X
X
X
X
X
X
1.125 ECMWF Reanalysis
+/-
NLDN CG lightning
MCS #2
12Z/14
DT (K) and wind (knots)
X
MCS #2
PV tail
mesoscaledisturbance
X
X
X X
X
XX
X
XX
1.125 ECMWF Reanalysis
+/-
NLDN CG lightning
00Z/15
DT (K) and wind (knots)
X
MCS #3
PV tail
mesoscaledisturbance
X
X
XX
X
X
XX
1.125 ECMWF Reanalysis
+/-
NLDN CG lightning
12Z/15
DT (K) and wind (knots)
X
MCS #3
PV tail
mesoscaledisturbance
X
XX
X
XX
1.125 ECMWF Reanalysis
+/-
NLDN CG lightning
H
L
PV Tail
Strong Jet
mesoscale disturbancesource region
Schematic for 13–15 July 1995
DT flow X
X
X
CG Lightning 12–15 July CG Lightning 12–15 July 19951995
12–13 13–14 14–15+/- +/- +/-
NLDN
Storm Reports 12–15 July Storm Reports 12–15 July 19951995
MCS #1
MCS #2
MCS #3
Reports associatedwith PV tail
tornadowindhail
+Generated using SeverePlot v2.5Source: Storm Prediction Center
tornado/wind reportsnear persistent trough
850 e (K), 925–500 wind shear (knots), 850–500 lapse rate (K km-1)
00Z/13–15 July 19951.125 ECMWF Reanalysis
850 e (K), 925–500 wind shear (knots), 850–500 lapse rate (K km-1)
00Z/13–15 July 1995
2300 J kg-1
00Z/13
1.125 ECMWF Reanalysis
Univ. Wyoming
850 e (K), 925–500 wind shear (knots), 850–500 lapse rate (K km-1)
00Z/13–15 July 1995
7000 J kg-1
00Z/13
1.125 ECMWF Reanalysis
Univ. Wyoming
850 e (K), 925–500 wind shear (knots), 850–500 lapse rate (K km-1)
00Z/13–15 July 19951800 J kg-1
00Z/14
1.125 ECMWF Reanalysis
Univ. Wyoming
% Contribution of JJA to Yearly % Contribution of JJA to Yearly Precipitation 1948–2003Precipitation 1948–2003
%UPD
% Contribution of 12–15 Jul to JJA % Contribution of 12–15 Jul to JJA ClimoClimo
%UPD
~25%
~20–30%
Case Study SummaryCase Study Summary
Downstream development led to ridge Downstream development led to ridge building over the Intermountain Westbuilding over the Intermountain West
As CA moved eastward, convection As CA moved eastward, convection formed on the periphery in association formed on the periphery in association with mesoscale disturbances and a PV tailwith mesoscale disturbances and a PV tail Serial severe MCSs formed on poleward sideSerial severe MCSs formed on poleward side
High CAPE, high shear environmentHigh CAPE, high shear environment Scattered convection formed on equatorward Scattered convection formed on equatorward
sideside Moderate CAPE, low-moderate shear environmentModerate CAPE, low-moderate shear environment
Climate ImplicationsClimate Implications RainfallRainfall
MCSs on periphery contributed ~25% of MCSs on periphery contributed ~25% of climatological JJA precipitationclimatological JJA precipitation
Mesoscale disturbances can produce intense Mesoscale disturbances can produce intense rain events and/or severe weather eventsrain events and/or severe weather events
TemperatureTemperature Subset of CAs that build over Intermountain Subset of CAs that build over Intermountain
West, then move eastward can produce heat West, then move eastward can produce heat waveswaves
Climatologically hot air over Intermountain Climatologically hot air over Intermountain West must be displaced to “anomalous” West must be displaced to “anomalous” regionsregions
Postscript:Postscript:Upper-level Upper-level
disturbances, disturbances, PV tails, and tropical PV tails, and tropical
systemssystems
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
06Z/16
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
12Z/16
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
18Z/16
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
00Z/17
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
06Z/17
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
12Z/17
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
18Z/17
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
00Z/18
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
06Z/18
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
12Z/18
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
18Z/18
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
00Z/19
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
06Z/19
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
12Z/19
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
18Z/19
Low-levelVorticity center
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
00Z/20
PV tail thinningand breaking
Source: NCDC GIBBSGOES-12
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
06Z/20
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
12Z/20
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
18Z/20
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
00Z/21
Source: NCDC GIBBSGOES-12
DT (K), wind (knots), and 925–850 hPa (10-5 s-1)
06Z/21
Jerry?
1345Z/21VIS
1445Z/21VIS
1545Z/21VIS
1645Z/21VIS
Source: http://www.coolwx.com/buoydata
Source: http://www.rap.ucar.edu/weather/surface
17Z/21
~40 knots at landfall
TPC Forecast from 12Z/21
Source: http://cimss.ssec.wisc.edu/tropic2/
Source: http://euler.atmos.colostate.edu/%7Evigh/guidance/index.htm
Extra slidesExtra slides
July 2006 CA over USJuly 2006 CA over US
500 hPa mean (dam; solid contours),anomaly (dam; shaded), and wind (knots; standard barbs)
15–22 July 2006
1.0 NCEP–GFS Analyses
00Z/16DT (K) and wind (knots)
380 J kg-1
1680 J kg-1
Univ. of Wyoming
XX
1.0 NCEP–GFS Analyses
12Z/16DT (K) and wind (knots)
1500 J kg-1
Univ. of Wyoming
X
XXX
10000
16000
15000
14000
13000
12000
11000
Date/Time (UTC)
He
igh
t MS
L (m
)
NOAA Profiler Obs
12Z/14
DT (K) and wind (knots)
X
Lapse Rate Climatology• 1973–2007• Summer (JJA)• 1200 UTC soundings
Conditions:• > 8.5 K km-1
• > 2500 m deep• 850–400 hPa layer
100200200
100
300
500
700
200100
100
February 2004 over February 2004 over AustraliaAustralia
200 hPa Height and Anomaly (dam),and Wind (m/s) for 1–22 Feb 2004
2.5 NCEP–NCAR Reanalysis
12Z/14
DT (K) and wind (knots)
IR
X
PV tail
mesoscaledisturbance
1.0 NCEP–GFS Analyses
T1
T2
12Z/17
DT (K) and wind (knots)
IR
X
PV tail
mesoscaledisturbance
X
X
1.0 NCEP–GFS Analyses
XX
T1
T2
Mean Resultant Gradient-level Wind for January
Figure from Atkinson (1971)
Monsoon trough
Trade winds
Monsoon flow
Is there a significant contribution from DT disturbances on the equatorward side of continental anticyclones to climatological monsoon precipitation over northern Australia?
Australia