Forecasting Oceanic Cyclones at the NOAA

Ocean Prediction CenterJoseph M. Sienkiewicz, D. Scott Prosise, and Anthony Crutch

NOAA/NWS/NCEP/Ocean Prediction CenterCamp Springs, MD

TimelineSanders and Gyakum, 1980 – Defined the meteorological oceanic “BOMB”

Anthes et al., 1983 – QE-II Storm – “…major improvements…through…improved initial conditions, improved horizontal and vertical resolution and changes in the physical

parameterization of surface fluxes and latent heating.”

1986-Genesis of Atlantic Lows Experiment (GALE)

Sanders, 1986 – “LFM is able to capture essentials of the baroclinic process, and that the amount of response

to baroclinic forcing remains intractable.”

1988-89 Experiment on Rapidly Intensifying Cyclones over the Atlantic (ERICA)

Sanders (1992) – “the state of the art in prediction of marine cyclones has advanced substantially over the last 15 years”

Uccellini et al., 1999 – “…the occurrence and position of intense, fast moving oceanic storms can be forecast in the day-4 time range.”

OPC Graphical Forecast Verification

48 Hour Surface Forecast VT 1200 UTC 18 Mar 2004

96 Hour Surface Forecast VT 1200 UTC 18 Mar 2004

Verifying Surface Analysis1200 UTC 18 Mar 2004

MethodologyFor all observed cyclones

Compare forecast & analyzed Position

Central pressure Wind warning category

OOCL AmericaPacific - Jan 2000

350 containers lost overboard 217 crushed or bent out of usable condition.

Vessel lost power for a short periodand took several severe rolls.

OPC Extratropical Cyclone Track Error for 48 and 96 hour Forecasts (All Cyclones)

45

81

116

150

225

282

374

143

240157

295

0

50

100

150

200

250

300

350

400

12 24 36 48 72 96 120

Forecast Hour

Err

or

(NM

)

TPC ATLC TC TrackError (1993-2002)

ATLC (2003-2004)

PAC (2003-2004)

OPC Extratropical Cyclone Track Error for 48 and 96 hour Forecasts (cyclones 980 hPa or less)

45

81

116

150

225

282

374

103

208

136

260

0

50

100

150

200

250

300

350

400

12 24 36 48 72 96 120

Forecast Hour

Err

or

(NM

)

TPC ATLC TC TrackError (1993-2002)

ATLC (2003-2004)

PAC (2003-2004)

OPC Extratropical Cyclone Track Error for 48 and 96 hour Forecasts (965 hPa or less)

45

81

116

150

225

282

374

84

185132

209

0

50

100

150

200

250

300

350

400

12 24 36 48 72 96 120

Forecast Hour

Err

or

(NM

)

TPC ATLC TC TrackError (1993-2002)

ATLC (2003-2004)

PAC (2003-2004)

OPC Extratropical Cyclone Track Error for 48 and 96 hour Forecasts (Hurricane Force Cyclones)

45

81

116

150

282

374

64

242

123

279

225

0

50

100

150

200

250

300

350

400

12 24 36 48 72 96 120

Forecast Hour

Err

or

(NM

)

TPC ATLC TC TrackError (1993-2002)

ATLC (2003-2004)

PAC (2003-2004)

October 2003 through March 2004

P-228

A-170

A-350

P-279

- Sanders, 1988-89(A-AtlanticP-Pacific)

Categorical Position Errors

OPC Cyclone Forecast Position Errors (Categorical)

0

50

100

150

200

250

300

350

ALL 980 or less 965 or less Hurcn Force

Cyclone Category

Err

or

(NM

) 48 HR ATLC

48 HR PAC

96 HR ATLC

96 HR PAC

P48-228

A48-170

A96-350

P96-279 P96-284P96-284

P96-248P96-248

P96- Uccellini et alP96- Uccellini et al1993-941993-94

A,P;48,96 – Sanders 88-89A,P;48,96 – Sanders 88-89

Categorical MSLP ErrorsOPC Cyclone MSLP Errors (Bias)

(Categorical)

-1

0

1

2

3

4

5

6

7

8

9

ALL 980 orless

965 orless

HurcnForce

Storm Gale

Cyclone Category

Av

g. E

rro

r (h

Pa

)

48 HR ATLC

48 HR PAC

96 HR ATLC

96 HR PAC

Warning Verification (% Correct)

0

10

20

30

40

50

60

70

80

Percent Correct (%)

48 hrATLC

48 HRPAC

96 HRATLC

96 HRPAC

Forecasts

Warning Forecasts (Categorical) (Percent Correct)

HURCN FORCE

STORM

GALE

Warning Verification

0

10

20

30

40

50

60

70

80

Percent (%)

HURCN FORCE STORM GALE

Warning Category

48 HOUR PACIFIC

Overforecast

Correct

Underforecast

0

10

20

30

40

50

60

70

Percent (%)

HURCN FORCE STORM GALE

Warning Category

96 HOUR PACIFIC

Overforecast

Correct

Underforecast

0

10

20

30

40

50

60

70

80

Percent (%)

HURCN FORCE STORM GALE

Warning Category

48 HOUR ATLANTIC

Overforecast

Correct

Underforecast

0

10

20

30

40

50

60

70

Percent (%)

HURCN FORCE STORM GALE

Warning Category

96 HOUR ATLANTIC

Overforecast

Correct

Underforecast

ConclusionsRemarkable progress in 25 years!!!

48 and 96 hour extratropical cyclone forecasts comparable or exceed 10 year average track errors for Atlantic Tropical Cyclones

Track error less for Atlantic than Pacific for all categories of cyclonesHurricane Force – track error significantly higher than other

categories of strong cyclones for 96 hour forecasts

Mean pressure errors - tendency to underforecast highest for extreme stormserror larger for Atlantic than Pacific (96 hours, 965 hPa or less)

Warnings – Difficulty forecasting intensity of the hurricane force eventtend to underforecast by one warning category

NWP Forecast windsNWP Pressure errorsShort lived events (24 hours or less)

Future WorkImprove day 4 forecasts of Hurricane Force Cyclones

Climatology of extreme eventsReanalysis data, cyclone phase diagrams

Are we missing something?SST, small scale structure

Ensembles - Improve deterministic forecasts

- Develop a suite of ensemble based probabilistic forecastsMust educate the customer

Forecasts for 6 to 10 day period