QBO Update

[Guest]

I was looking at some information. Actually showing my son some stuff, and I noticed we are moving into, or already have moved into the westerly QBO phase. This is faster then forecast, and we are alos seeing above average SST's in the Tropical Atlantic.
I'm not going to change my numbers, but they may be under estimated.
here is an exerpt from my 2004 predictions released April 1, 2004:
Quasi-Biennial Oscillation (QBO) Index:

This will be a Westerly, favorable direction this season. With the lack of a strengthening ENSO, and the easterly QBO that we had during the early portions of last season. A westerly phase of the QBO shows an additional favorable parameter to allow conditions for development of Tropical Cyclogenesis in the Tropics.
This is how the QBO affects Tropical Cyclogenesis are as follows:
This allows for greater coupling between the lower stratosphere and the troposphere allowing for a more favorable environment for development.
So a westerly QBO is in favor due to the fact we had a easterly QBO late spring 2003 and the early portion of the 2003 hurricane season. And weaker winds from east to west due to a weaker Atlantic Ridge. This indicates a more active Cape Verde Hurricane Season then we have seen the past few seasons.
We started last season in a easterly QBO, where we were in a neutral phase in September 2003. Based on the anomalies as shown in CPC Tropical Diagnostics Bulletin we are now seeing a negative anomaly (issued March 12, 2004) and this should become a westerly phase as we move into the second quarter of the 2004 hurricane season. Thus being and moving further into a favorable westerly QBO as we head into August, September, and October 2004. From Gray et al. (1992, 1993, 1994) and Shapiro (1989): a) Atlantic TC activity is inhibited during easterly phases of the QBO due to enhanced lower stratospheric wind ventilation and increased upper-troposphere-lower-stratosphere wind shear, and b) for slow moving systems, the west phase of the QBO has a slower relative wind (advective wind relative to the moving system) than does the east phase. This allows for greater coupling between the lower stratosphere and the troposphere.
On top of this, the ITCZ is becoming ever more active with localized tropical waves exiting the African Coast.
I still will hold at 14 named storms, 8 hurricanes, 3 majors. These storms will develop from 18 tropical depressions.
So hold onto your hats folks, it's going to be a bumpy ride!!!

[Stormsfury]

Actuall, BB ... the switch to a westerly phase of the QBO occurred in February 2004 ... from very strong EAST during July-Oct ...

Code: Select all

Year     Jan     Feb     Mar     Apr     May    June    July     Aug     Sept     Oct     Nov     Dec   
2003   -1.39   -1.44   -3.30   -8.57  -13.94  -18.01  -22.99  -24.64  -22.51  -20.34  -17.86  -11.38
2004   -4.84    2.61    5.45   10.46   12.97 -999.00 -999.00 -999.00 -999.00 -999.00 -999.00 -999.00


SF

[Guest]

Where did you get that?

[Stormsfury]

Where did you get that?

QBO data since 1948 from CDC ...

SF

[USAwx1]

http://www.cdc.noaa.gov/correlation/qbo.data

The QBO should be peaking in the positive (west) phase sometime during the height of the season.

BTW, Nice description of the QBO and it's impact on the tropical season!

[Anonymous]

I was looking at some information. Actually showing my son some stuff, and I noticed we are moving into, or already have moved into the westerly QBO phase. This is faster then forecast, and we are alos seeing above average SST's in the Tropical Atlantic.
I'm not going to change my numbers, but they may be under estimated.
here is an exerpt from my 2004 predictions released April 1, 2004:
Quasi-Biennial Oscillation (QBO) Index:

This will be a Westerly, favorable direction this season. With the lack of a strengthening ENSO, and the easterly QBO that we had during the early portions of last season. A westerly phase of the QBO shows an additional favorable parameter to allow conditions for development of Tropical Cyclogenesis in the Tropics.
This is how the QBO affects Tropical Cyclogenesis are as follows:
This allows for greater coupling between the lower stratosphere and the troposphere allowing for a more favorable environment for development.
So a westerly QBO is in favor due to the fact we had a easterly QBO late spring 2003 and the early portion of the 2003 hurricane season. And weaker winds from east to west due to a weaker Atlantic Ridge. This indicates a more active Cape Verde Hurricane Season then we have seen the past few seasons.
We started last season in a easterly QBO, where we were in a neutral phase in September 2003. Based on the anomalies as shown in CPC Tropical Diagnostics Bulletin we are now seeing a negative anomaly (issued March 12, 2004) and this should become a westerly phase as we move into the second quarter of the 2004 hurricane season. Thus being and moving further into a favorable westerly QBO as we head into August, September, and October 2004. From Gray et al. (1992, 1993, 1994) and Shapiro (1989): a) Atlantic TC activity is inhibited during easterly phases of the QBO due to enhanced lower stratospheric wind ventilation and increased upper-troposphere-lower-stratosphere wind shear, and b) for slow moving systems, the west phase of the QBO has a slower relative wind (advective wind relative to the moving system) than does the east phase. This allows for greater coupling between the lower stratosphere and the troposphere.
On top of this, the ITCZ is becoming ever more active with localized tropical waves exiting the African Coast.
I still will hold at 14 named storms, 8 hurricanes, 3 majors. These storms will develop from 18 tropical depressions.
So hold onto your hats folks, it's going to be a bumpy ride!!!

I like the numbers, though I think that 4 MHs are more likely. 14 NS and 8 H still appears to be on track since the QBO has little influence on those #s.

[Stormsfury]

I like the numbers, though I think that 4 MHs are more likely. 14 NS and 8 H still appears to be on track since the QBO has little influence on those #s.

1996, and 2003 are proof positive of that statement ... (BOTH YEARS the QBO was STRONGLY EAST during the heart of the respective seasons)...