2017 EPAC Season

[weathaguyry]

I think there is a valid argument towards a dead EPAC season, the PDO last year was near +2.5, but in 2017 there is a fairly neutral PDO with a stream of cold anomalies down the West Coast, despite the warm water south of Hawaii. The Instability is currently very low, and this needs to change in order to get bunches of hurricanes like we have seen in previous years. If the instability stays low, we may just see mainly sloppy storms that never really get their act together.

[ig]http://www.ssd.noaa.gov/PS/TROP/TCFP/data/current/ts_ep_nep_THDV.gif[/img]

The PDO is a decadal variable that means if it's at pro longed positive values, then we're in a warm phase. If there are pro longed negative values, then we're in a cold phase. There's no neutral phase, nor can there be considerations of short term oscillations in its monthly readings. So because it's in a positive state, we'll see its positive effects toward the EPAC hurricane season. Because if we're going to consider a +1.00 PDO a "fairly neutral PDO" and consider it as a not so favorable variable anymore, look at the PDO numbers for 1992:

Code: Select all

1992     0.05   0.31   0.67   0.75   1.54   1.26   1.90   1.44   0.83   0.93   0.93   0.53

IMO, the PDO appears to be closer to neutral at the current moment, in 1992 the PDO came in at 1.54 which is probably higher than it will come in for May once the JISAO updates their numbers. The EPAC as a whole doesn't look too great, but I think that a storm like Iniki of 1992 is very possible, because it took advantage of the warm waters south of Hawaii, I think Hawaii should really watch out this year. Because moisture that translates over into the CPAC may develop into Hurricanes, but since they are farther out the Pacific they will cause less shear for the Atlantic. Also, do you know when the JISAO will release the PDO numbers for May?

[Kingarabian]

I think there is a valid argument towards a dead EPAC season, the PDO last year was near +2.5, but in 2017 there is a fairly neutral PDO with a stream of cold anomalies down the West Coast, despite the warm water south of Hawaii. The Instability is currently very low, and this needs to change in order to get bunches of hurricanes like we have seen in previous years. If the instability stays low, we may just see mainly sloppy storms that never really get their act together.

[ig]http://www.ssd.noaa.gov/PS/TROP/TCFP/data/current/ts_ep_nep_THDV.gif[/img]

The PDO is a decadal variable that means if it's at pro longed positive values, then we're in a warm phase. If there are pro longed negative values, then we're in a cold phase. There's no neutral phase, nor can there be considerations of short term oscillations in its monthly readings. So because it's in a positive state, we'll see its positive effects toward the EPAC hurricane season. Because if we're going to consider a +1.00 PDO a "fairly neutral PDO" and consider it as a not so favorable variable anymore, look at the PDO numbers for 1992:

Code: Select all

1992     0.05   0.31   0.67   0.75   1.54   1.26   1.90   1.44   0.83   0.93   0.93   0.53

IMO, the PDO appears to be closer to neutral at the current moment, in 1992 the PDO came in at 1.54 which is probably higher than it will come in for May once the JISAO updates their numbers. The EPAC as a whole doesn't look too great, but I think that a storm like Iniki of 1992 is very possible, because it took advantage of the warm waters south of Hawaii, I think Hawaii should really watch out this year. Because moisture that translates over into the CPAC may develop into Hurricanes, but since they are farther out the Pacific they will cause less shear for the Atlantic. Also, do you know when the JISAO will release the PDO numbers for May?

The PDO being @ +2.00, +1.50, +1.25, +0.75, +0.50, all mean the same thing. It means that that the PDO is positive, and a warm phase is present.

I think they release it on the 15th, so look for it next week. It'll come in at +.80/+.90, which means the warm phase will continue.

[Yellow Evan]

IMO, the PDO appears to be closer to neutral at the current moment.

It's not that simple. The mutli-decade phase of PDO has been positive, and that serves as a major benefit to the basin.

[Yellow Evan]

Yes, we've seen 2 short-lived tropical storms that, when combined, amount to the lowest ACE output on record in the East Pacific for the first two named storms.

2013 AHS saw 3 named storms by the first week of July, including a MDR storm that was supposed to signal a very busy year. Much good that did.

Well when you compare it to last season where we nearly had the latest start on record for the EPAC while last season having better conditions, any storm forming now means the talk about poor conditions in the EPAC are for naught.

I don't know about comparing the Atlantic hurricane season with the Pacific hurricane season, but the key variables are there for the EPAC to be active this season.

Warm PDO continues its reign.
Near average shear.
Above average SST's.

That's pretty much what we look for in the EPAC.

The only thing that's really bad is the vertical instability, which tends to favor a spam of tropical storms rather than a spam of major hurricanes. Worth noting, however, that quality vs. quantity in the EPAC tends to be cyclical and seems somewhat correlated with QBO - http://www.geo.fu-berlin.de/met/ag/stra ... gapore.dat. Given the current QBO phase, we may see stronger late season storms as QBO turns back negative, but in general, that's an EPAC trend noted throughout the database as well.

[Ntxw]

Yeah there is no such thing as a neutral PDO, just like there is no neutral AMO. They are long term conglomerate signals and it's either positive or negative. They can wax and wane with strength of ENSO (tends to rise with Ninos and lower with Ninas, in between the swings are not dramatic) but then the influence is in ENSO by that fact.

[Alyono]

Yes, we've seen 2 short-lived tropical storms that, when combined, amount to the lowest ACE output on record in the East Pacific for the first two named storms.

2013 AHS saw 3 named storms by the first week of July, including a MDR storm that was supposed to signal a very busy year. Much good that did.

Well when you compare it to last season where we nearly had the latest start on record for the EPAC while last season having better conditions, any storm forming now means the talk about poor conditions in the EPAC are for naught.

I don't know about comparing the Atlantic hurricane season with the Pacific hurricane season, but the key variables are there for the EPAC to be active this season.

Warm PDO continues its reign.
Near average shear.
Above average SST's.

That's pretty much what we look for in the EPAC.

The only thing that's really bad is the vertical instability, which tends to favor a spam of tropical storms rather than a spam of major hurricanes. Worth noting, however, that quality vs. quantity in the EPAC tends to be cyclical and seems somewhat correlated with QBO - http://www.geo.fu-berlin.de/met/ag/stra ... gapore.dat. Given the current QBO phase, we may see stronger late season storms as QBO turns back negative, but in general, that's an EPAC trend noted throughout the database as well.

was shown more than a decade ago that QBO has no affect on TC activity

[dexterlabio]

It's interesting how people can make a pronouncement that this year will see less activity than last year, more so a dead season. For one, last year's EPAC didn't get its first named storm until July, and AFAIK had the record of longest period without a named tropical storm. EPAC had 2 short-lived TS so far, and if we are being conservative, this year is on par with 2016 at this point. If there are any evidences that suggest the PDO switching to negative or the ENSO going to cold neutral at the very least, then we have a more valid argument.

[Yellow Evan]

Latest runs of ECMWF, GFS-P, and ECMWF-P all show Calvin in about 5-6 days, but will likely be short-lived.

[Kingarabian]

Latest runs of ECMWF, GFS-P, and ECMWF-P all show Calvin in about 5-6 days, but will likely be short-lived.

After Calvin, the 00z Euro parallel abandons GOM development, and instead has Hurricane Dora in the EPAC.

[Yellow Evan]

As a result of this, CFS is showing some uptick in activity in the long range.

[Yellow Evan]

000
ABPZ20 KNHC 100502
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Fri Jun 9 2017

For the eastern North Pacific...east of 140 degrees west longitude:

A broad area of low pressure located a couple hundred miles south-
southeast of the Gulf of Tehuantepec is currently producing only
limited shower and thunderstorm activity. However, some gradual
development of this system is possible during the next several days
while it moves slowly west-northwestward to northwestward along or
near the coast of Mexico.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...30 percent.

$$
Forecaster Brennan

[cycloneye]

Up to 20%-40%.

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sat Jun 10 2017

For the eastern North Pacific...east of 140 degrees west longitude:

1. Showers and thunderstorms have increased a little today in
association with a broad area of low pressure located a couple of
hundred miles south of the Gulf of Tehuantepec. Some gradual
development of this system is possible during the next few days
while it moves slowly west-northwestward to northwestward along or
near the coast of Mexico. Regardless of development, locally heavy
rains should spread over the coasts of El Salvador, Guatemala, and
southeastern Mexico during the next few days.
* Formation chance through 48 hours...low...20 percent.
* Formation chance through 5 days...medium...40 percent.

Forecaster Cangialosi

[cycloneye]

INVEST 92E is up.

[Kingarabian]

INVEST 92E is up.

92W?

[cycloneye]

INVEST 92E is up.

92W?

Fixed.

[Yellow Evan]

Raw SST profile not too good right now and likely preventing anything remotely west.

[Kingarabian]

Looks pretty favorable per CIMSS.

[Yellow Evan]

CFS shows more favorable conditions next month as we get a more robust MJO hopefully.

[Kingarabian]

EPS consistently showing Dora past the 10 day mark.

[Kingarabian]

Expect the EPAC MDR to warm up if this pattern of consistent low pressure close to the sub-tropics from the Euro and GFS materializes.

GFS:


Euro: