My take on things:

[USAwx1]

First, some reasoning (the method behind MY madness)

ENSO ----> NEUTRAL to somewhat cooler than average through at least September, especially the E-PAC NINO regions 1+2, and 3.0; consistent with the persistent slow decrease in SSTA over the entire equatorial PAC since DEC:

2003 12 22.99 0.15 25.56 0.47 29.02 0.75 26.89 0.42
2004 1 24.60 0.09 25.92 0.30 28.83 0.68 26.74 0.23
2004 2 25.81 -0.22 26.46 0.10 28.59 0.58 26.86 0.17
2004 3 25.94 -0.54 27.16 0.08 28.43 0.34 27.10 -0.05

ftp://ftpprd.ncep.noaa.gov/pub/cpc/wd52 ... oi.indices

In FEB, anomalous upper level easterly zonal winds were observed off the northeast coast of South America, which would suggest that the upward portion of the walker circulation is located in the western PAC, implying the onset of La Nina conditions, however, other critical factors such as OLR (Outgoing Longwave Radiation) indices, 200 MB zonal winds, SOI, and MJO have shown too much variability to suggest the onset of La Nina conditions. That being said, there have been some indications aside from those which were previously discussed that DO support the development of weak La Nina conditions.

- Suppressed convection and correspondingly drier than average conditions over the central EQPAC.

- Enhanced easterly zonal winds between 160E and 150W.

Both of which have correlated nicely with the downturn in SSTA observed over the region since this past December after a long period of borderline El Nino conditions thru much of 2003 Atlantic hurricane season.

PDO -----> LONG TERM COLD CYCLE

The current long-term PDO cold phase (which began in 1998) would suggest a downswing in tropical cyclone activity over the eastern pacific and an upswing in Atlantic basin activity, as well as more frequent and stronger ENSO cold episodes.

http://jisao.washington.edu/pdo/PDO.latest

From a short-term standpoint, The PDO has been positive consistently since AUG of 2002, in concert with the pervious moderate El Nino that dominated the 2002-03 winter. Once it declined in the spring of 2003, the PDO remained positive throughout the remainder of the year, and has not budged since (through MAR 04, though has not been overwhelmingly positive). Values have remained below 1.00 since APR 03, telling me that in conjunction with the mixed signals from other factors, the continuation of ENSO neutral conditions are a good bet at least for the next few months. Thus the ENSO should have little effect on the 2004 Atlantic basin season. Thereafter, it will be interesting to see what happens.

QBO -----> WEST

A west (positive) QBO has a marked enhancing effect on Atlantic basin tropical cyclone activity. The QBO turned positive this FEB, and will continue to increase positive over the next few months. The QBO WILL be positive for the entire 2004 Atlantic tropical season.

ATC----> STRONG CYCLE

Warmer than average SSTA across the Atlantic basin suggest that the Atlantic thermohaline circulation (ATC) has shifted into the strong cycle, and implies a bias toward the negative phase of the NAO, consistent with the observed above average 500 MB height anomalies over the far North Atlantic this past winter.

During the ATC strong phase, heat and energy is more evenly distributed, and there must be a mechanism which the atmosphere uses to transport the additional heat and energy northward from the tropics through the mid-latitudes and the Polar Regions, this mechanism is tropical cyclones. So because there is more heat and energy to transport out, more tropical cyclone activity results over a period of several years. Similarly, during these periods the NAO and AO tend to be biased negative.

The negative (cold) phase of the PDO (Pacific Decadal oscillation) is observed, and the corresponding Pacific SSTA configuration supports more frequent ENSO cold (La Nina) episodes.

Heres a break down of other factors which are forced by the ATC and what the resultant effect is:

-Atlantic SSTA (North Atlantic and Tropical Atlantic):
Warmer than average

-AO (Arctic oscillation) favored phase on a decadal and multi-decadal sale:
Mostly Negative

-Global Surface temperature (mean and anomaly):
Below Average

-Indian Monsoon:
Above Average

-Atlantic basin TC activity:
Above Average

-Eastern Pacific basin TC activity:
Below Average

-Sahel Rainfall:
Above Average

-The Southern hemispheric PV (Polar vortex):
Weaker than average

-The ENSO (El Nino – Southern Oscillation):
More frequent and stronger cold episodes

-The PDO (Pacific Decadal oscillation):
Cold phase

-The PNA (Pacific – North America teleconnection):
Mostly negative (RNA pattern)

-The NAO (North Atlantic Oscillation):
Mostly negative

A –NAO supports toughing along the east coast of north America, over the north Atlantic, which at times can become especially persistent and intense. The correlation/teleconnection between the NAO and various atmospheric patterns across North America is maximized during the MAR-APR period. Also, low SLP associated with this is observed across the Caribbean, which similarly favors enhanced activity the following season.

The current ATC strong cycle began in 1995, and is consistent with the recent upswing in Atlantic basin tropical cyclone activity since 1996. Warm SSTA is currently located across much of the Atlantic basin would support a negative NAO, and enhanced tropical cyclone activity in the Atlantic basin this season. The reduced tropospheric vertical wind shear associated with this is also favorable for increased TC formation.

Numbers (based on selected analogs):

13 Named Storms
8 Hurricanes (CAT 1-5)
4 Major (CAT 3-5)

Landfall probability (CAT 1 Hurricane or stronger):

Much above average. ESPECIALLY along the east coast of North America, south of the Delmarva to the Florida Panhandle. SOMEWHAT LESS of a threat along the Gulf coast, and MUCH less of a threat north of the Delmarva.

Best chance for impact from a major (CAT 3-5) hurricane along the US coastline:

Florida, along the Atlantic Side

Periods to watch for the BEST likelihood of a major landfall along the US coastline:

Early AUG – Mid SEPT.

[rainstorm]

good write-up

[cycloneye]

Good anaylisis that you did there about all the factors and by the way welcome to storm2k.

[Stephanie]

Welcome to S2K! Excellent write-up of your opinion on what maybe in store for us during the Tropical season.

[Rainband]

Welcome to S2K. Nice Forecast. I hope your right about the GOM.

[Lindaloo]

WOW!! Excellent analysis! Welcome to S2K...

[Typhoon_Willie]

Great analysis and welcome to Storm2k!

[Guest]

Yep, I agree with everyone else... Great analysis & welcome aboard.

[Stormsfury]

Great write-up, and welcome USAwx1 ...

13/7/3 are also my prelim numbers (from last month) after re-evaluation of many factors and the progged ENSO for early 2004 failed to materialize ... furthermore, there were many periods where the winter season exhibited La Niña like patterns with stronger blocking episodes, and hence, drier than normal conditions re-appearing in the Southeast ...

Originally, my mid-December release originally was going for a normal season with uncertainties in the degree of the ENSO state ... with various models in a wide state of disagreement ...

CLICK HERE for my Mid-December Tropical Atlantic Prognostic Discussion where I cited the analog years (heavily on) 1887, 1933, 1936, and 1969 and 1995 and 2001-2002 ... To break each year, and the following years TC activity ... (breakdown of the seasons within the prog. disc. above...

Again, welcome to Storm2k, USAwx1 ...

SF

[Matthew5]

Great discussion USAwx1

In Stormsfury the years 1933 and 1995 where the most active season in history

[Stormsfury]

Great discussion USAwx1

In Stormsfury the years 1933 and 1995 where the most active season in history

In the AOML re-analysis project from 1851-1910, 1887 was also found to have 19 storms as well (along with the only other time that TWO December storms formed).

[USAwx1]

Great write-up, and welcome USAwx1 ...

13/7/3 are also my prelim numbers (from last month) after re-evaluation of many factors and the progged ENSO for early 2004 failed to materialize ... furthermore, there were many periods where the winter season exhibited La Niña like patterns with stronger blocking episodes, and hence, drier than normal conditions re-appearing in the Southeast ...

Originally, my mid-December release originally was going for a normal season with uncertainties in the degree of the ENSO state ... with various models in a wide state of disagreement ...

CLICK HERE for my Mid-December Tropical Atlantic Prognostic Discussion where I cited the analog years (heavily on) 1887, 1933, 1936, and 1969 and 1995 and 2001-2002 ... To break each year, and the following years TC activity ... (breakdown of the seasons within the prog. disc. above...

Again, welcome to Storm2k, USAwx1 ...

SF

thanks. and EXCELLENT discussion also. I cited many of the same years, although Im somewhat hesitant to go ahead and predict another EXTREMELY active year when we just came off of one last season.

Also, to clear something up. I have heard some try to suggest that southeastern CANADA my be under the gun again this season. I dont agree, and the reason is pretty simple.

this is why --->

https://www.fnmoc.navy.mil/products/OTI ... nomaly.gif

Notice the wedge of cold SSTA running along from the southeast coast of Nova Scotia to newfoundland, with warmer SSTA over the far north Atlantic. GREAT set up for a -NAO but NOT good when looking for trouble in SE canada. those waters are simp;y to cold to sustain a tropical system. Of course its very early in the game, and that can change. but, on the flip side of the coin, IF SSTA remain anomalously cool in the aforementioned area through much of the tropical season, its doubtful that southeast canada would be threatened as it was last year.

in some seasons such as last when southeast canada was targeted, SSTA were running well ABOVE average in the same area.

https://www.fnmoc.navy.mil/products/OTI ... nomaly.gif

[Stormsfury]

I've also noticed that, although the overall conditions are neutral, the SST anomalies in the equatorial regions EAST of 120ºW are running well below normal ... and the last update that I had continued to show cold pools developing (about a month ago, was the last available update to me) 50-100m deep swinging eastward ...

I also believe this cold anomaly is PARTLY responsible for the drier conditions across the Southeast up to this point ...

SF

[USAwx1]

I've also noticed that, although the overall conditions are neutral, the SST anomalies in the equatorial regions EAST of 120ºW are running well below normal ... and the last update that I had continued to show cold pools developing (about a month ago, was the last available update to me) 50-100m deep swinging eastward ...

I also believe this cold anomaly is PARTLY responsible for the drier conditions across the Southeast up to this point ...

SF

and much of the latest data suggests the continuation of ENSO neutral through at least JUL, w/ the exception of the outlier NSIPP.

http://www.cdc.noaa.gov/seasonalfcsts/sst/lag1.html

some further warming takes place in the AUG-OCT Period...and if one disregards the NSIPP, the rest of the data looks good.

http://www.cdc.noaa.gov/seasonalfcsts/sst/lag4.html

bringing EQPAC SSTA back to slightly warm neutral (if one considers the AVG of all the 6 models).

but the bottom line still that ENSO neutral conditions will dominate the 2004 atlantic tropical season.

and....your probably right about the connection between the cold pool in the eastern NINO regions and the dry conditions over the southeast as of late. what should be intetesting to see (and i know this isnt related to tropical wx, but i feel i should mention it anyway) is if that la Nina-like signal has an enhancing effect on severe weather the remainder of this spring and into the early summer.

[USAwx1]

same deal with the NCEP model. Its been showing Warm ENSO connditions for months now, which to date, have not materialized.