SIX INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES 2006 IWTC-VI SAN JOSE, COSTA RICA NOVEMBER 2006
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Transcript of SIX INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES 2006 IWTC-VI SAN JOSE, COSTA RICA NOVEMBER 2006
SIX INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES 2006
IWTC-VI
SAN JOSE, COSTA RICA
NOVEMBER 2006
TOPIC 0.1
QUANTITATIVE FORECASTS OF TROPICAL CYCLONES LANDFALL IN RELATION TO AN EFFECTIVE WARNING SYSTEM: TRACK
FORECASTS
LIXION A. AVILA RSMC MIAMI
SIX INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES 2006
IWTC-VI
SAN JOSE, COSTA RICA
NOVEMBER 2006
TOPIC 0.1
WORKING GROUP:
PHILLIPE CAROFF, JEFF CALLAGHAN, JAMES FRANKLIN and
MARK DeMARIA
0
50
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150
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350
24-h 48-h 72-h 96-h 120-h
landfall
all storms
Average track forecast errors (nm) for the 1 to 5 day period before landfall (2001-2005)
RSMC LA REUNIONTime-evolution of
Cyclone tracks forecasts errors (5-years running means of direct position errors)
(All intensities)
1426 1515 1660 1619 1358 1344 1253 1211 1355 1522 1506
1035 1226 1483 1509 1288 1285 1214 1197 1332 1491 1476
495 532 568 657 664851 929 1132 1277 1435 1424
397435
470 484 411441 432 467 542 742 874
0
50
100
150
200
250
300
350
400
450
500
550
90/91 -94/95
91/92 -95/96
92/93 -96/97
93/94 -97/98
94/95 -98/99
95/96 -99/00
96/97 -00/01
97/98 -01/02
98/99 -02/03
99/00 -03/04
00/01 -04/05
analysis
12 h forecasts
24 h forecasts
48 h forecasts
0
100
200
300
400
500
600
700
19
65
19
70
19
75
19
80
19
85
19
90
19
95
20
00
20
05
Year
Mea
n F
ore
cast
Err
or
(nm
i)NHC64
NHC67
HURRAN
CLIPER
NHC72
NHC73
NHC83
NHC90
NWP-BAR
SANBAR
VICBAR
BAMD
LBAR
MFM
QLM
GFDL
GFS
UKMET
NOGAPS
OFCL
0
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12
18
24
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36
42
1963-1969 1970-1979 1980-1989 1990-1999 2000-2005
Time Interval
Ave
rag
e L
ead
Tim
e (h
r)
Average Lead Time of NHC Hurricane Warnings By Decade
Katrina Track ForecastsKatrina Track Forecasts1200 UTC 24 August1200 UTC 24 August
Katrina Track ForecastsKatrina Track Forecasts0000 UTC 27 August0000 UTC 27 August
Rita Track Forecasts Rita Track Forecasts 1200 UTC 21 September1200 UTC 21 September
Rita Track Forecasts Rita Track Forecasts 1200 UTC 21 September1200 UTC 21 September
Severe left bias in track modelsSevere left bias in track models
Rita Track ForecastsRita Track Forecasts1200 UTC 22 September1200 UTC 22 September
Rita Track ForecastsRita Track Forecasts1200 UTC 22 September1200 UTC 22 September
Remarkable improvement in track guidance: Likely the impact of surveillance data from the NOAA G-IV jet?
Remarkable improvement in track guidance: Likely the impact of surveillance data from the NOAA G-IV jet?
Ophelia Track Forecasts (nightmare)Ophelia Track Forecasts (nightmare) 1200 UTC 9 September 1200 UTC 9 September
Wilma Track Models10/21/05 18z
Navy GFDL 72 h
NCEP GFDL 72 h
U.K. Met. Office 72 h
GFS 72 h
NOGAPS 72 h
Verifying position 10/24/05 18z
Excellent example of GUNA consensus: HURRICANE ISABEL, 1200 UTC 11 SEP 2003Excellent example of GUNA consensus: HURRICANE ISABEL, 1200 UTC 11 SEP 2003
Not-so-excellent example of GUNA consensus:
HURRICANE KATE, 1800 UTC 29 SEP 2003
This is a case where forming a selective consensus can be effective.
Not-so-excellent example of GUNA consensus:
HURRICANE KATE, 1800 UTC 29 SEP 2003
This is a case where forming a selective consensus can be effective.
New Tropical Cyclone Wind Speed Probability Products from NHC
Richard Knabb, Chris Landsea, Edward Rappaport, Michelle Mainelli, Chris Lauer, Alison Krautkramer, James Franklin, and Jamie Rhome
National Hurricane Center
Scott Kiser and Tim Schott - NWS Headquarters
Mark DeMaria – NESDIS and John Knaff - CIRA
June 2006
Existing TPC/NHC Products Used to Convey Uncertainty
Watch/Warning Graphic
Indicates forecast track and long-term mean error
Need for improved means of conveying tropical cyclone forecast uncertainty to various types of users
– New product is about a weather event at any specific location
– Conveys chances of wind speeds of at least particular thresholds
• 34 kt (tropical storm force)• 50 kt• 64 kt (hurricane force)
– Accounts for combined uncertainty in track, intensity, and size
– Extends to 5 days– Includes inland locations– Replaced strike probabilities in 2006
Why a new probability product?
Challenges and Ongoing Work• Significant training and outreach needed
– Lessen the focus on exact track forecast– Do users understand probabilities?– Getting familiar with the probability values– “Small” probabilities of an extreme event
• Enhancements to graphical products– Faster creation of grids, and the graphics created from them
• Objective guidance for watch/warning breakpoints
• Eventual use by NWS forecast offices in their products
• Verification
• Gridded products for NDFD
• Discussion