Observed and Forecast Tracks: Northern Hemisphere 2011

All tropical cyclones in the northern hemisphere season in 2011 are listed below including details of their start and end dates and maximum sustained wind (MSW). Qualitative comments are included on the performance of the Met Office global model in predicting the track of each tropical cyclone.

Click on the name of the tropical cyclone to see a chart of the observed track and forecast tracks from the Met Office global model. Verification statistics on each tropical cyclone are available upon request from tropical_cyclones@metoffice.gov.uk. At the end of the season a verification report on the performance of the Met Office global model will be published.

North-west Pacific
Name & IDStart & end dates1-/10-minute MSWComments on Met Office global model forecasts
01W02-03 April30/- knots01W did not attain tropical storm status and no forecasts were verified.
02W05-06 April30/- knots02W did not attain tropical storm status and no forecasts were verified.
Aere (03W)06-11 May50/45 knotsTrack forecast errors were mixed compared to last season's values, but skill was high at longer lead times. The landfall on Luzon was fairly well predicted.
Songda (04W)20-29 May140/105 knotsTrack forecast errors were mostly below last season's average. There was a left of track and slow bias resulting a slightly late prediction of recurvature and extratropical transition. However, skill scores against CLIPER were high.
Sarika (05W)09-11 June35/40 knotsSarika was only briefly a tropical storm
Haima (06W)16-24 June35/40 knotsThere was a slight right-of-track bias early on, but overall track forecast errors were below last season's average and skill scores were very high.
Meari (07W)21-27 June60/60 knotsTrack forecast errors were very low and skill scores high for this storm. There was a slight slow bias at longer lead times.
Ma-on (08W)   11-24 July  115/95 knotsMa-on was a long-lived typhoon with several changes in direction. On the whole these changes in direction were well predicted by the model. The track errors were near to last season's average. There was a slow and left-of-track bias overall, but skill scores against CLIPER were high.
Tokage (09W)15-16 July30/35 knotsTokage was designated a tropical storm by JMA, but not JTWC. It was short-lived and no forecasts were verified.
Nock-ten (10W)24-30 July65/50 knotsThe track of Nock-ten was very well predicted with low track forecast errors. Skill scores against CLIPER were also high.
Muifa (11W)24 July-08 August

140/95 knots

Forecast track errors were above last season's average, although skill scores were positive. The model turned Muifa too sharply westwards towards Taiwan.
Merbok (12W)03-09 August80/55 knotsThe model erroneously stalled Merbok resulting in some large timing errors in the prediction of recurvature. Hence, track forecast errors were generally large.
13W10-12 August30/30 knots13W did not reach tropical storm strength and no forecasts were verified.
Nanmadol (14W)22-31 August135/105 knotsAlthough the model had a right-of-track bias, its forecasts for Nanmadol were much better than some other models in predicting a track close to the Philippines and towards Taiwan. Hence, track errors were below last season's average.
Talas (15W)25 August-05 September55/65 knotsThe majority of forecast tracks for Talas were good resulting in track forecast errors below last season's average.
Noru (16W)03-06 September45/40 knotsTrack forecast errors were below average for this storm
Kulap (17W)07-10 September45/35 knotsKulap was only briefly a tropical storm and few forecasts were verified.
Roke (18W)11-22 September115/95 knotsRoke's rapid acceleration across Japan was well predicted close to the event, but earlier forecasts kept the typhoon slow-moving south of Japan. Due to the large distance travelled by the typhoon as it raced across Japan, some of the forecast errors from earlier forecasts were very large. Overall, track forecast errors were above last season's average.
Sonca (19W)14-20 September85/70 knotsTrack forecasts for Sonca were mostly good and errors were below last season's average.
Nesat (20W)23-30 September105/80 knotsA couple of early forecasts erroneously predicted a north-westward turn resulting in large longer lead time errors. However, track errors at shorter lead times were low.
Haitang (21W)24-27 September35/35 knotsTrack forecast errors were low for Haitang.
Nalgae (22W)27 September-05 October130/95 knotsForecast track errors were below average for this storm and skill scores against CLIPER were high.
Banyan (23W)10-14 October35/35 knotsDespite persisting for several days as a tropical depression, Banyan was only briefly a tropical storm and just one forecast was verified.
24W
07-08 November30/- knots24W was a tropical depression and no forecasts were verified.
25W04-05 December30/- knots25W was a tropical depression and no forecasts were verified.
26W12-13 December30/30 knots26W was a tropical depression and no forecasts were verified.
Washi (27W)13-19 December55/40knotsTrack forecast errors were below last season's average for this late season storm.

North-West Pacific observed tracks in 2011
North-West Pacific tropical cyclone names

North-east Pacific
Name & IDStart & end dates1-minute MSWComments on Met Office global model forecasts
Adrian (01E)07-12 June120/- knotsTrack forecast errors were low and skill scores high with just a slight slow bias for this hurricane.
Beatriz (02E)19-22 June75/- knotsForecast tracks were too far to the left resulting in a failure to predict the proximity of the track to land.
Calvin (03E)07-10 July70 knotsCalvin was relatively short lived. Track forecast errors were low and skill scores high.
Dora (04E)18-24 July135 knotsThe direction and speed of motion of Dora were very well predicted with only slight deviations at longer lead times. Forecast errors were low and skill scores high.
Eugene (05E)31 July-06 August115 knotsEugene was a straight-running storm which was well predicted in nearly all forecasts. Hence, track forecast errors were very low.
Fernanda (06E)16-20 August55 knotsTrack forecast errors were low and skill scores high for this storm.
Greg (07E)16-21 August75 knotsTrack forecast errors were slightly above last season's average, but were still low.
08E31 August-01 September30 knots08E did not reach tropical storm strength and no forecasts were verified.
Hilary (09E)21-30 September125 knotsTrack forecasts for Hilary were generally good and forecast errors below last season's average.
Irwin (11E)06-17 October80 knotsTrack forecast errors for Irwin were near to last season's average. The turn back eastwards early in its life was well predict
Jova (10E)06-13 October110 knotsTrack forecast errors were near to last season's average. The hurricane's changes in direction were generally well handled, although the final acceleration northwards near landfall was not.
12E12-13 October30 knots12E did not reach tropical storm status and no forecasts were verified.
Kenneth (13E)19-25 November125 knotsKenneth was the latest season major hurricane ever recorded in this region. Track forecasts were very good with low errors and high skill scores. The formation of the hurricane was also well predicted.
Central North Pacific
Name & IDStart & end dates1-minute MSWComments on Met Office global model forecasts

North-East and Central North Pacific observed tracks in 2011

North-East Pacific tropical cyclone names

Central North Pacific tropical cyclone names
North Atlantic
Name & IDStart & end dates1-minute MSWComments on Met Office global model forecasts
Arlene (01L)28 June-01 July55/- knotsThe few forecasts which were verified had track errors below last season's average.
Bret (02L)17-22 July55 knotsThe track of Bret was well predicted. Track errors were low and skill scores high.
Cindy (03L)20-22 July50 knotsCindy was a tropical storm for less than two days, but in this time track forecasts were very good.
Don (04L)27-30 July45 knotsDon was a tropical storm for a couple of days and in this time track forecasts and the location of landfall were very well predicted.
Emily (05L)  02-07 August45 knotsThere was a fast bias in forecasts for Emily resulting in track forecast errors above last season's average.
Franklin (06L)12-14 August40 knotsFranklin was short-lived and only one forecast was verified.
Gert (07L)14-16 August  50 knotsThe few forecasts for this storm that could be verified had a left-of-track bias.
Harvey (08L)19-22 August50 knotsHarvey was short-lived as a tropical storm and only a few forecasts were verified.
Irene (09L)20-29 August105 knotsEarly forecasts had a left-of-track bias and later forecasts a slow bias at longer lead times. Overall, this resulted in short lead time track forecast errors being near last season's average, but longer lead time errors being higher than average. Skill scores against CLIPER were positive, but not high.
10L25-27 August30 knots10L did not reach tropical storm strength and no forecasts were verified.
Jose (11L)28-29 August40 knotsJose was a short-lived storm and no forecasts were verified.
Katia (12L)29 August-10 September115 knotsTrack forecast errors were low and skill scores against CLIPER high for short lead times (up to 72 hours). However, longer lead time forecasts had a left-of-track and slow bias resulting in higher than average track forecast errors. The model handled the extra-tropical transition and subsequent impact on the UK well.
Unnamed01-02 September40 knotsThis short-lived storm was added to the list in post-season reanalysis
Lee (13L)02-05 September50 knotsLee was well predicted by the model - track forecast errors low and skill scores high.
Maria (14L)06-16 September70 knotsTrack forecast errors were near to average at short lead times and above average at longer lead times due to a left-of-track bias. Skill scores against CLIPER were high.
Nate (15L)07-12 September60 knotsTrack forecast errors were near to last season's average. Forecast tracks were a little too far north, but skill scores were high.
Ophelia (16L)21 September-03 October120 knotsAt short lead times track forecast errors were low, but at longer lead times they were high. This was primarily due to the failure to predict the period when Ophelia degenerated and was quasi-stationary midway through its life. The northward acceleration during extratropical transition was generally well handled.
Philippe (17L)24 September-09 October80 knotsEarly forecasts turned Philippe northwards too quickly. Some later forecasts also predicted extratropical transition too soon. However, the main change from a westward to eastward track was fairly well handled. Track forecast errors were mostly above last season's average.
Rina (18L)23-28 October95 knotsThe track of Rina was well forecast and forecast errors were below last season's average.
Sean (19L)08-12 November55 knotsTrack forecast errors were low and skill scores high for this storm

North Atlantic observed tracks in 2011

North Atlantic tropical cyclone names
North Indian
(forecast track charts for Global and South Asia models shown)
Name & IDStart & end dates1-/10-minute MSWComments on Met Office global model forecasts
01A11-12 June35/30 knots01A only briefly reached tropical storm status according to JTWC.
02B19 October35/30 knots02B only briefly reached tropical storm status according to JTWC.
Keila (03A)02-03 November35/35 knotsKeila was a short-lived storm and only one 12-hour forecast was verified.
04A07-09 November35/- knots04A was short-lived as a storm and the few forecast verified had higher than average track forecast errors.
05A26-30 November35/30 knotsTrack forecast errors were low for this storm and skill scores against CLIPER, particularly at longer lead times, were high.
Thane (06B)25-30 December80/65 knotsTrack forecast errors were very low and skill scores very high for this storm. All but the first forecast predicted the landfall location and timing very well.

North Indian observed tracks in 2011

North Indian tropical cyclone names


Note on estimated wind speeds

1-minute MSW: Maximum sustained wind (knots) averaged over 1 minute (JTWC Hawaii, NHC Miami, CPHC Hawaii)

10-minute MSW: Maximum sustained wind (knots) averaged over 10 minutes (JMA Japan, IMD New Delhi)
Note: Although 1-minute average winds should be stronger than 10-minute average, this may not be the case here since estimates are obtained from different warning centres.

Last updated: 17 December 2013