ATCF Requirements, Intensity Consensus

Sea Heights Consistent with NHC Forecasts

(Progress Report)

Presenter

Buck Sampson (NRL Monterey)

Investigators

Ann Schrader, Efren Serra (SAIC, Monterey)

Paul Wittmann (FNMOC)

Hendrik Tolman (NCEP)

Mike Frost (NRL, Monterey)

Collaborators

Chris Sisko, Chris Lauer, Jessica Schauer (NHC)

Andrea Schumacher, John Knaff and Mark DeMaria (CIRA)

IHC 2011Miami

Tasks

1. NHC User Requirements for ATCF (80% Complete)

2. Intensity Consensus (Complete)

3. Sea Heights Consistent with NHC Forecasts (80% Complete)

1. User Requirements for ATCFHighlights

-ATCF Requirements Lists (FY 2010 and 2011)

-60 hr forecasts

-Capability to save TWO disturbance probabilities

-Expanded seas radii capability (>995 nm)

-Other NHC/JHT/HFIP Requests

-GPCE version of wind probabilities

-“Display Only” version of Web-ATCF

-Large ensemble ingest, retention and display

-ATCF Documentation

Sixty Hour Forecast Capability

Intensity

Track

Wind Radii

Capability to save TWO disturbance probabilities

Transition disturbance to a storm

TWO disturbance entry

Disabled Menu Items

Web-ATCF “Display Only” Mode

Disabled functions throughout application. Allows no advisories, no communication with web

pages, no storm file updates. Near real-time updates on live tropical cyclones.

Large ensemble ingest, storage, display

1000 MC Wind Probability realizations. ATCF can now handle

up to 1300 aids for a single date. Still needs color for intensity.

Online Documentation

•ATCF Users Manual (300 pages)•ATCF System Administrators Guide (50 pages)•ATCF Installation Guide (10 pages)•ATCF Storm Archive Management (2 pages)•ATCF Objective Best Track Guide (5 pages)•fasDB (GRIB and Bufr Database) Guide (25 pages)•ATCF Storm Database Format (20 pages)•GUI documentation (1000 pages)•22 ATCF related journal articles

Link to documents: http://www.nrlmry.navy.mil/atcf_web/docs/ATCF-FAQ.html

2. Intensity Consensus

• Forecasts are all “early models”• Consensus is average forecast• 2006: INT3 = DSHP + GHMI + GFNI• 2007: INT4 = DSHP + GHMI + GFNI + LGEM• 2008: IVCN = DSHP+ GHMI + GFNI + LGEM + HWFI

ICON = DSHP+ LGEM + GHMI +

HWFI

* As of 2008, NHC names consensus and defines input guidance.

More info: Sampson, C. R., J. L. Franklin, J. L., J. A. Knaff and M. DeMaria, 2007:

Experiments with a simple tropical cyclone intensity consensus. Wea. And Forecasting,

23, 304-312.

Intensity Skill Relative to 2006 NHC Intensity Consensus

Atlantic 2009-2010

-10123456789

10

0 1 2 3

Forecast Day

Skill

(%

)

ICON

IVCN

IVCN+COAMPS

DSHP:+GHMI+GFNI+LGEM+COAMPS

(507) (385) (294) (234)

(DSHP+GHMI+GFNI+LGEM +COAMPS-TC) provided most skill relative to 2006

Intensity Consensus (DSHP+GHMI+GFNI). COAMPS-TC forecasts real-time at NRL

in 2010. 2009 reruns courtesy of Yi Jin (NRL). Evaluation does not contain landfall.

Intensity Skill Relative to 2006 NHC Intensity Consensus

Atlantic 2009-2010

-10123456789

10

0 1 2 3

Forecast Day

Skill

(%

)

ICON

IVCN

IVCN+COAMPS

DSHP:+GHMI+GFNI+LGEM+COAMPS

(507) (385) (294) (234)

(DSHP+GHMI+GFNI+LGEM +COAMPS-TC) provided most skill relative to 2006

Intensity Consensus (DSHP+GHMI+GFNI). COAMPS-TC forecasts real-time at NRL

in 2010. 2009 reruns courtesy of Yi Jin (NRL). Evaluation does not contain landfall.

Significant Improvement of

3-4% Over IVCN!

3. Sea Heights Consistent with Official Forecast

(OFCL/WW3)

1. Obtain GFS sfc winds

2. Cut out model vortex

3. Generate OFCL vortex

4. Insert OFCL in GFS sfc winds

5. Run WW3

6. Similar in concept to NAH WW3

(Modified) Goals for 2010:

Algorithm:

1. Produce grib files for NAWIPS

2. Use 6-h old GFS run to reduce latency

3. Run real-time at NRL

4. ATCF output for 12-ft seas radii

3. Sea Heights Consistent with Official Forecast

(OFCL/WW3)

1. Obtain GFS sfc winds

2. Cut out model vortex

3. Generate OFCL vortex

4. Insert OFCL in GFS sfc winds

5. Run WW3

6. Similar in concept to NAH WW3

(Modified) Goals for 2010:

Algorithm:

1. Produce grib files for NAWIPS

2. Use 6-h old GFS run to reduce latency

3. Run real-time at NRL

4. ATCF output for 12-ft seas radii

Buoy 41048 during Igor

0

1

2

3

4

5

6

7

8

9

1 15 29 43 57 71 85 99 113 127 141 155 169 183 197 211 225 239

Time ->

Sig

Wa

ve

Ht

(M)

Buoy 41048

WW3 Hindcast 10-min

WW3 Hincast 1-min

Buoy 41044 during Igor

0

2

4

6

8

10

12

14

1 14 27 40 53 66 79 92 105 118 131 144 157 170 183 196 209 222 235 248 261 274 287 300

Time ->

Sig

Wav

e H

t (M

)

Buoy 41044

WW3 Hindcast 10-min

WW3 Hindcast 1-min

Buoy 41047 During Earl

0

2

4

6

8

10

12

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211

Time --->

Sig

Wav

e H

t (M

)

OFCL/WW3 10-min

OFCL/WW3 1-min

OFCL/WW3

OFCL/WW3 Hindcasts vs Buoys

TAFB Eval: OFCL/WW3 sea heights 5-6ft low (ouch!)

Buoy 41046 During Earl

0

2

4

6

8

10

12

14

16

18

20

1 12 23 34 45 56 67 78 89 100 111 122 133 144 155 166 177 188 199 210

Time --->

Sig

Wav

e H

t (M

)

Buoy 41046

OFCL/WW3 10-min

OFCL/WW3 1-min

OFCL/WW3 Radii of 12-ft Seas Evaluation Using TAFB Analysis as Ground Truth

Improved biases

Need to revisit wind radii assignment beyond 72 h as some

expansion of wind radii needed (use DRCL?). Also possibly

removing too much of background winds during vortex insertion.

3. Sea Heights Consistent with Official Forecast

(OFCL/WW3)

Remaining Tasks for 2011:

1. Implement in NHC environment (underway)

2. Documentation (underway)

3. Real-time runs in NHC environment in 2011

4. Experiments with modified algorithms (if time permits)

Progress Summary

1. NHC User Requirements for ATCF (80% complete)

2. Intensity Consensus Review and Update (complete)

3. Sea Heights Consistent with NHC Forecasts (80% complete)

EXPERIMENTAL TC-COR GUIDANCE

SITE TC-COR

Agrihan 2 Alamagan 2 Anatahan 2 Pagan 2 Saipan 3 Tinian 4

•Based on Watches/Warnings and cumulative wind probabilities in the Atlantic and Gulf of Mexico (CIRA)•Strategic objective guidance for onset of 50-kt winds at military installations•Does not include local effects or base sensitivities

TC-COR Threshold Probabilities Forecast Lead 4 5% 72 H 3 6% 48 H 2 8% 24 H 1 12% 12 H

(NRL, CIRA, NOAA/NESDIS)

EXPERIMENTAL TC-COR GUIDANCE

SITE TC-COR

Agrihan 2 Alamagan 2 Anatahan 2 Pagan 2 Saipan 3 Tinian 4

•Based Watches/Warnings and cumulative wind probabilities in the Atlantic and Gulf of Mexico (CIRA)•Strategic objective guidance for onset of 50-kt winds at military installations•Does not include local effects or base sensitivities

TC-COR Threshold Probabilities Forecast Lead 4 5% 72 H 3 6% 48 H 2 8% 24 H 1 12% 12 H

(NRL, CIRA, NOAA/NESDIS)

Why so low?

Why are the TC-COR guidance thresholds so low?

•Guidance should step through conditions sequentially•Times should correspond to those in operations, if possible•Shouldn’t miss a wind event

Objective TC-COR Settings for 26W 2004 at Yokosuka

Current Thresholds Double Current Thresholds Quadruple Current Thresholds(Maximum Threat Scores)

4 (-70 hours) 4 Missed 4 Missed

3 (-34 hours) 3 (-34 hours) 3 Missed

2 (-16 hours) 2 Missed 2 Missed

1 (-10 hours) 1 (-10 hours) 1 (-10 hours)

55 kt (Oct 9 1634) 55 kt (Oct 9 1634) 55 kt (Oct 9 1634)

Why are the TC-COR guidance thresholds so low?

•Guidance steps through conditions sequentially•Times are reasonable•This guidance was *not* available to forecasters in real-time

Objective TC-COR Settings for 26W 2004 at Yokosuka

Current Thresholds Double Current Thresholds Quadruple Current Thresholds(Maximum Threat Scores)

4 (-70 hours) 4 Missed 4 Missed

3 (-34 hours) 3 (-34 hours) 3 Missed

2 (-16 hours) 2 Missed 2 Missed

1 (-10 hours) 1 (-10 hours) 1 (-10 hours)

55 kt (Oct 9 1634) 55 kt (Oct 9 1634) 55 kt (Oct 9 1634)

TC-COR 1 EVALUATION

•82 cases •10 Navy and Air Force bases •WestPac, Atlantic•1996-2009

TC-COR 1 Forecast vs Base Setting (73 Cases)

Observed YesObserved No

Forecast Yes 10 15

Forecast No 0 57

Observed YesObserved No

Forecast Yes 20 3

Forecast No 9 41

TC-COR 1 Forecast vs Observed Wind Near Site (82 Cases)

Misses

False Alarms

Threat Score=.625

Threat Score=.4