1. A look at hurricane force extratropical cyclones
Joseph M. Sienkiewicz
NOAA/NWS/NCEP Ocean Prediction Center
Michael J. Brennan
NOAA/NWS/NCEP Hydrometeorological Prediction Center
Cadet 1/c Shea G. Winterberger
U.S. Coast Guard Academy
Outline
7 yr. QuikSCAT climatology
forecast performance
12 km WRF results
food for thought
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

2. Hurricane Force Extratropical Cyclone
kts
Intense, non-tropical cyclones
with hurricane force winds
Feb 09, 2007, North Atlantic
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

3. Preliminary Aircraft Comparison – GPS dropsondes
kts
Wind Speed (Knots)
Before QuikSCAT, hurricane force intensity extratropical cyclones were rarely observed, certainly with little consistency as forecasters relied only on conventional observations from ships of opportunity and buoys. With QuikSCAT, the OPC and NWS started issuing hurricane force wind warnings. NOAA P-3 based observations from SFMR and GPS dropsondes are shown in the form of wind barbs overlaid upon the concurrent QuikSCAT pass of ocean surface vector winds. Although these results are very preliminary there indeed is agreement between the three sources of wind.
February, 9th 2007
Coincident QuikSCAT and aircraft wind measurement reveals HF winds in an extratropical storm in the North Atlantic
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

4. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
Extratropical Cyclones with Hurricane Force Winds Detected using QuikSCAT
Hurricane Force Warning Initiated Dec 2000
Detection increased with:
Forecaster familiarity
Data availability
Improved resolution
Improved algorithm
Improved wind
algorithm and
rain flag Oct 06
WARNING
CATEGORIES
Pre- QSCAT
1. GALE kt
2. STORM >48
QSCAT ERA
2. STORM kt
3. HURCN FORCE
> 64 kt
12.5 km QuikSCAT
available May 04
25 km QuikSCAT
Available in N-AWIPS
Oct 01
Hurricane Force
Wind Warning
Initiated Dec 00
A paper by Von Ahn et al, 2006 demonstrated that QuikSCAT’s impact on OPC operations was most significant for higher wind warning categories of STORM (48 to 63 knots) and HURRICANE FORCE (64 knots and greater). With the loss of QuikSCAT capability, in all likelihood the number of routine GALE events will increase and then number of STORM and HURRICANE FORCE will decrease.
Draft Report by Haute Kite-Powell, Feb 2008: “Benefits to Maritime Commerce from Ocean Surface Vector Wind Observations and Forecasts” – Ocean Surface Vector Winds and Maritime Commerce.
244
235
QuikSCAT
Launch
Jun 99
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008 4

5. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
Climatology
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

6. Geographic distribution of cyclones with winds of HF intensity
Major Shipping Routes
North Atlantic
The geographic distribution of all cyclone centers that contained hurricane force conditions for the north Atlantic basin. Peak activity was found to occur northeast of Newfoundland centered on 53N and 46W with a maxima of activity stretching toward Iceland. A second maximum was observed south of Nova Scotia. The domain extended from the coast of North America to the Prime Meridian.
Geographic distribution of cyclones with winds of HF intensity
Sep-May
7 yr average number of extratropical cyclones observed (contoured)
with hurricane force winds for the years
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

7. Geographic distribution of cyclones with winds of HF intensity
Major Shipping Routes
North Pacific
As in the previous figure except for the Pacific basin. Peak activity was observed over the western portion of the basin with a smaller maximum at 172 degrees west and an even smaller peak east of 160 degrees west longitude.
Geographic distribution of cyclones with winds of HF intensity
Sep-May
7 yr average number of extratropical cyclones observed (contoured)
with hurricane force winds for the years
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

8. Cyclone Forecast skill
Pacific
Atlantic
48.0
96.0 N
MSLPE
MPE
All Cyclones
700.0
0.7
124.4
222.7
528.0
0.1
126.4
-0.5
207.8
Hurcn Force
41.0
-1.1
102.3
-5.5
225.2
-0.7
82.4
-3.3
184.2
734.0
1.7
152.9
0.8
248.0
601.0
0.0
119.5
214.3
33.0
-3.9
126.5
-11.8
197.2
52.0
-1.8
115.2
-5.4
216.9
MSLPE – Mean Sea-Level Pressure Error (hPa)
MPE – Mean Position Error (nmi)
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

9. Hurricane Force Warning - Forecast skill
Pacific
Atlantic
POD
FAR
48hr
0.51
0.40
0.68
0.03
96hr
0.24
0.52
0.37
0.29
0.36
0.45
0.15
0.55
0.31
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

10. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
Workstation WRF
7 Hurricane Force cases
-ARW core version 2.1.2
-operational GFS forecasts for initial and lateral boundary conditions
-1/12th degree RTG SST analysis (NCEP/MMB)
-Kain-Fritsch convective parameterization scheme
-Lin et. al microphysics
-YSU PBL scheme
-MM5 surface layer physics
-RRTM long wave and Dudhia short wave radiation ARW Core
Max 10 m Winds (knots)
Atlantic
GFS
WRF12
WRF Gust
7-Dec-05 62 59 76
9-Feb-07 78 77 93
10-Feb-07 70 72 85
9-Mar-08 67
Pacific
22-Dec-07 64
11-Feb-08 69 83
14-Feb-08 66 81
1 Atlantic non-Hurricane Force case
Dec 25, 2007
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

11. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
Onset of Hurricane Force winds preceded by development of intense bent back front
WRF 1800 UTC Feb 11, 2008
F008 VT 0200 UTC Feb 12,2008
925 hPa theta gradient
10 m isotachs
65, 50, 35 kt
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

12. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
WRF 1200 UTC Mar 09, 2008
F008 VT 0000 UTC Mar 10,2008 A B
kts
PMSL
10 m wind speeds
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

13. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
WRF 1200 UTC Mar 09, 2008
F008 VT 0000 UTC Mar 10,2008 A B A
925 hPa theta-e gradient
PMSL
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

14. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
WRF 1200 UTC Mar 09, 2008
F008 VT 0000 UTC Mar 10,2008
A B
Theta-e
Theta-e gradient
Isotachs
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

15. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
WRF 1200 UTC Mar 09, 2008
F008 VT 0000 UTC Mar 10,2008
A B
Omega
Ageostrophic Circulation
Isotachs
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008

16. Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008
Food for thought
Potential Mechanism for momentum transfer?
Coupling of synoptic-scale and thermally direct frontal circulation?
Predictability
Atlantic vs. Pacific?
Forecast improvement
Sensitivity to resolution
Ensemble approach or higher res deterministic?
Future probabilistic approach
Cyclone Workshop, Sainte-Adele, Quebec, Canada Sep 21-26, 2008