Hi there.

Got a question which I would really appreciate if some light could be shed on. With talk of La Nina event being present throughout the N Hemisphere summer many people are talking about the possibility of increased Atlantic hurricane activity.

But what about the Wpac? What effect does La Nina usually have on the number of storms or where they form?

Thanks in advance!

James.

Look at what happened the latter half of last year with the Phillippines. That type of a pattern is suppose to happen with a La Nina. Less storms further east and less recurvatures, more storms in the western part of the basin, and more impacts to the Phillippines.

A Post Nino year in WPAC generally is one of lower than normal activity. However, since we failed to see a typical Nino season last year, it's hard to say if we will see that this year. However, in terms of activity, last season was somewhat like the 1976 Nino season which makes sense since this past Winter in the West was much like the 1976-77 Nino especially in SoCA. With that in mind, the 1977 season was the lowest in activity in WPAC at the time.

Steve

Was 1977 the least active typhoon season? I know it was inactive in the EPAC and ATL. Same goes with the Southern Hemisphere. I know 1977 was not an El Nino year, even though some months had them. I read that in 1977 the Pacific Decadal Oscillation changed into "warm" phase. I wonder if that had anything to do with the inactive period.

http://www.prh.noaa.gov/cphc/summaries/

1977
Top
There were no tropical cyclones reported in the Central North Pacific during 1977. The Western North Pacific experienced the smallest number of typhoons (11) since JTWC's formation in 1959. Eastern North Pacific activity was also at a minimum; only 8 tropical storms or hurricanes were reported during the year in that area--the lowest number since 1966 when excellent satellite full coverage began.

Wow. Also, the Atlantic was very quiet, one of the least active on record. Normally a somewhat quieter Pacific season mean a more active Atlantic generally speaking. I know the Southern Hemisphere saw 25 total storms, which is somewhat below average of 28. The North Indian Ocean saw 6 storms, which is slightly above average. I always wondered about why 1977 was so quiet in almost all the Basins. It was a neutral year in terms of ENSO, other than an El Nino in some months. I looked looked Daily Mean Composites and the SST anomaly was below average in general. As for pressure anamoly, it was above average.

Thanks for the replies everyone!

I see the 1951 - 2005 average for number of TCs in the Wpac is 27 per year. The last 2 years have been below average with only 23 storms (however 2006 had record breaking number of intense typhoons.) Will be interesting to see what 2007 holds - could be quite a busy intercept season if there are more storms in the west!

I believe that eiyther the 1983 or 1998 season had fewer typhoons than 1977.

Steve

Both 1983 (10) and 1998 (8) had fewer typhoons than 1977 (11).

Typhoon
1977
19 Storms
11 Typhoons

1983
18 Storms
8 Typhoons

1998
18 Storms
9 Typhoons


Atlantic
1977
6 Storms
5 Hurricanes

1983
4 Storms
3 Hurricanes

1998
14 Storms
10 Hurricanes


East Pacific
1977
8 Storms
4 Hurricanes

1983
23 Storms
12 Hurricanes

1998
13 Storms
9 Hurricanes

Feel free to correct me. Got it off of Unisys and Wikipedia.

Digital Typhoon is the best place to find these things. http://www.digital-typhoon.org

As a rule La-Nina years will cause the westpacific tropical cyclones to form at higher latitudes, majority above 20N where in especially EL-nino years they tend to form at very low latiitudes like 5 to 8N and closer to the International Dateline. As a rule warm ENSO years favor activity reaching the Mariana Islands from the east also at peak strength. Recent years like 1990, 1991, 1992, 1997 and 2002 are good examples. Cool ENSO not only have the cyclones developing at a higher latitude they are mostly found west of longitude 140E.

Only problem is, we didn't see that type of activity during this Niño season and I think it was due to the fact that the highest SST anomalies were well east of the Niño 3.4 region during the peak of the season.

Steve