2015 EPAC Season

[Yellow Evan]

GFS seems off and on bout this, but ensemble support from both the GFS and CMC are still there.

[Yellow Evan]

GFS starting to show more consistency as the last 4 runs have now showed Andres. Ensemble support is still there as well.

[Kingarabian]

GFS starting to show more consistency as the last 4 runs have now showed Andres. Ensemble support is still there as well.

Convection seems to be on the increase in the Eastern East Pacific.

[Yellow Evan]

GFS starting to show more consistency as the last 4 runs have now showed Andres. Ensemble support is still there as well.

Convection seems to be on the increase in the Eastern East Pacific.

Likely associated with the MJO, though the GFS does not show Andres until around Day 12.

[Yellow Evan]

GFS has backed off, and in time, the time frame from this has not moved up. I'm starting to think this is phantom.

[Yellow Evan]

GFS seems to have abolished the idea of Andres, likely since it's having trouble forecasting the MJO.

[Ntxw]

Hello Epac, you ready? Good KW coming early May. May want to get settled, can't guarantee a storm but conditions will likely favor one.

[Yellow Evan]

12z and 18z GFs brought back Andres, but haven't really moved the time frame forward. the Pacific High is where has retrograded SE. The reason why that's important is because of the Coriolis effect and the fact the NPAC high is anticyclonic, meaning it flows clockwise. That's why systems tend to form on the SE peripherally of the ridge, since cyclonic activity goes counterclockwise. Winds are created when a high pressure region moves to a low pressure region. But the next step will be getting the ITCZ to lift northward. That is expected to take place within a week or so per the GFS, ECMWF, and CMC.

[Kingarabian]

12z and 18z GFs brought back Andres, but haven't really moved the time frame forward. the Pacific High is where has retrograded SE. The reason why that's important is because of the Coriolis effect and the fact the NPAC high is anticyclonic, meaning it flows clockwise. That's why systems tend to form on the SE peripherally of the ridge, since cyclonic activity goes counterclockwise. Winds are created when a high pressure region moves to a low pressure region. But the next step will be getting the ITCZ to lift northward. That is expected to take place within a week or so per the GFS, ECMWF, and CMC.

I sometimes think the EPAC has a brain of its own and does things differently.

[Yellow Evan]

12z and 18z GFs brought back Andres, but haven't really moved the time frame forward. the Pacific High is where has retrograded SE. The reason why that's important is because of the Coriolis effect and the fact the NPAC high is anticyclonic, meaning it flows clockwise. That's why systems tend to form on the SE peripherally of the ridge, since cyclonic activity goes counterclockwise. Winds are created when a high pressure region moves to a low pressure region. But the next step will be getting the ITCZ to lift northward. That is expected to take place within a week or so per the GFS, ECMWF, and CMC.

I sometimes think the EPAC has a brain of its own and does things differently.

It sorta does. There's less land and less fiction and less shear. And sometimes the SST gradient isn't very sharp, keeping storm's intensity.

But that's what it makes it so amazing. Some of the wildest things can happen with any given storm.

Who would have thought that Daniel in 2012 would have become a major when it formed?

Who would have thought that Amanda in 2014 would become a major hurricane, yet alone a near-Category 5 last year?

[Kingarabian]

12z and 18z GFs brought back Andres, but haven't really moved the time frame forward. the Pacific High is where has retrograded SE. The reason why that's important is because of the Coriolis effect and the fact the NPAC high is anticyclonic, meaning it flows clockwise. That's why systems tend to form on the SE peripherally of the ridge, since cyclonic activity goes counterclockwise. Winds are created when a high pressure region moves to a low pressure region. But the next step will be getting the ITCZ to lift northward. That is expected to take place within a week or so per the GFS, ECMWF, and CMC.

I sometimes think the EPAC has a brain of its own and does things differently.

It sorta does. There's less land and less fiction and less shear. And sometimes the SST gradient isn't very sharp, keeping storm's intensity.

But that's what it makes it so amazing. Some of the wildest things can happen with any given storm.

Who would have thought that Daniel in 2012 would have become a major when it formed?

Who would have thought that Amanda in 2014 would become a major hurricane, yet alone a near-Category 5 last year?

That's the beauty of it. And most of these storms are fishes. Great for science!

[Yellow Evan]

I sometimes think the EPAC has a brain of its own and does things differently.

But that's what it makes it so amazing. Some of the wildest things can happen with any given storm.

Who would have thought that Daniel in 2012 would have become a major when it formed?

Who would have thought that Amanda in 2014 would become a major hurricane, yet alone a near-Category 5 last year?

That's the beauty of it. And most of these storms are fishes. Great for science!

Indeed. Especially this year I think we're in store for a lot of fishes and thus probs a lot of annulars.

Still some ensemble support for Andres around day 10-14.

[Kingarabian]

Indeed. Especially this year I think we're in store for a lot of fishes and thus probs a lot of annulars.

Still some ensemble support for Andres around day 10-14.

I would love to see for the NHC to start including real forecasts for annulars.

Example:

Instead of: This storm has the potential to become annular / This storms forecast is complicated by the chances of it turning annular

To: This storm's windfield is smaller than previously thought and environment conditions permit the transition to annular status towards the end of the forecast. We give this storm a 50% chance of becoming annular. While there is some dry air ahead, this storm may survive because of its annular status and re-intensify once it reaches more favorable conditions.

[Yellow Evan]

Indeed. Especially this year I think we're in store for a lot of fishes and thus probs a lot of annulars.

Still some ensemble support for Andres around day 10-14.

I would love to see for the NHC to start including real forecasts for annulars.

Example:

Instead of: This storm has the potential to become annular / This storms forecast is complicated by the chances of it turning annular

To: This storm's windfield is smaller than previously thought and environment conditions permit the transition to annular status towards the end of the forecast. We give this storm a 50% chance of becoming annular. While there is some dry air ahead, this storm may survive because of its annular status and re-intensify once it reaches more favorable conditions.

Well, whether a storm is annular or not is a bit subjective as it is. And honestly, there's no long-term use (no annular storm has hit land while still annular). Would be kinda cool though.

It's pretty clear cut to tell whether a storm will at least resemble annular characteristics. You need 24-26C SSt's (28+C SST's make storms top vertically deep, so they can support rainbands without losing their balance of heat), not so sharp SST gradient, and most importantly, low shear.

Given that SST's are above near E of Hawaii (so instead of 23-24C they are now 25-26C), this could allow for a system to maintain it's intensity near Hawaii, provided there is no great Hawaiian Shear, which there was very little of for the most part in 2014.

[cycloneye]

Only looking at this mess on April 27 let me to believe the EPAC 2015 season will be very active / Hyperactive.

[Yellow Evan]

Kimberlain tweeted about it twice this morning.

Todd Kimberlain @ToddKimberlain · 9h 9 hours ago

The eastern Pacific hurricane season really wants to start early. #hurricane #Pacific #weather #wx #storms

Todd Kimberlain @ToddKimberlain · 5h 5 hours ago

Could Kelvin wave near 110E initiate epac hurricane season? #hurricane #Pacific #epac #kelvin #tropics

Here's another thingy about why this PHS may start early from Kimberlain

[Yellow Evan]

Kimberlain tweeted about it twice this morning.

Todd Kimberlain @ToddKimberlain · 9h 9 hours ago

The eastern Pacific hurricane season really wants to start early. #hurricane #Pacific #weather #wx #storms

Todd Kimberlain @ToddKimberlain · 5h 5 hours ago

Could Kelvin wave near 110E initiate epac hurricane season? #hurricane #Pacific #epac #kelvin #tropics

Here's another thingy about why this PHS may start early from Kimberlain

[Kingarabian]

FARTHER SOUTH...THE TROPICAL EPAC IS STARTING TO
TRANSITION TO ITS LATE SPRING/SUMMER PATTERN...WITH SIGNIFICANT
MID LATITUDE INFLUENCES. WHAT WAS A COHERENT ITCZ IS BREAKING
DOWN INTO A LARGE AREA OF EAST TO WEST ORIENTED TROUGHING ALONG
ROUGHLY 10N...ALTHOUGH WITH FAIRLY WEAK AND INCONSISTENT
SOUTHERLY FLOW. A MID/UPPER LEVEL SHORT WAVE TROUGH IS EVIDENT
ON WATER VAPOR IMAGERY APPROACHING FROM THE NW...PROVIDING
SUPPORT TO A LARGE AREA OF MODERATE TO STRONG CONVECTION AROUND
A 1007 MB SURFACE LOW CENTERED NEAR 06N116W. GUIDANCE INDICATES
THIS LOW PRES WILL WEAKEN AND DISSIPATE THROUGH 48 TO 72 HOURS
AS IT DRIFTS W...AND AS THE SUPPORTING UPPER DYNAMICS SHIFT
EAST. BY THURSDAY...GUIDANCE IS IN GOOD AGREEMENT SHOWING
ANOTHER 1007 MB LOW PRES SE OF THE GULF OF TEHUANTEPEC...LIKELY
INFLUENCED BY THE SAME MID/UPPER DYNAMICS APPROACHING THE AREA
CURRENTLY.

[Yellow Evan]

FARTHER SOUTH...THE TROPICAL EPAC IS STARTING TO
TRANSITION TO ITS LATE SPRING/SUMMER PATTERN...WITH SIGNIFICANT
MID LATITUDE INFLUENCES. WHAT WAS A COHERENT ITCZ IS BREAKING
DOWN INTO A LARGE AREA OF EAST TO WEST ORIENTED TROUGHING ALONG
ROUGHLY 10N...ALTHOUGH WITH FAIRLY WEAK AND INCONSISTENT
SOUTHERLY FLOW. A MID/UPPER LEVEL SHORT WAVE TROUGH IS EVIDENT
ON WATER VAPOR IMAGERY APPROACHING FROM THE NW...PROVIDING
SUPPORT TO A LARGE AREA OF MODERATE TO STRONG CONVECTION AROUND
A 1007 MB SURFACE LOW CENTERED NEAR 06N116W. GUIDANCE INDICATES
THIS LOW PRES WILL WEAKEN AND DISSIPATE THROUGH 48 TO 72 HOURS
AS IT DRIFTS W...AND AS THE SUPPORTING UPPER DYNAMICS SHIFT
EAST. BY THURSDAY...GUIDANCE IS IN GOOD AGREEMENT SHOWING
ANOTHER 1007 MB LOW PRES SE OF THE GULF OF TEHUANTEPEC...LIKELY
INFLUENCED BY THE SAME MID/UPPER DYNAMICS APPROACHING THE AREA
CURRENTLY.

A few GFS ensembles do deepen this slightly, but not even the CMC shows it. I guess it bears watching though.

[Kingarabian]

FARTHER SOUTH...THE TROPICAL EPAC IS STARTING TO
TRANSITION TO ITS LATE SPRING/SUMMER PATTERN...WITH SIGNIFICANT
MID LATITUDE INFLUENCES. WHAT WAS A COHERENT ITCZ IS BREAKING
DOWN INTO A LARGE AREA OF EAST TO WEST ORIENTED TROUGHING ALONG
ROUGHLY 10N...ALTHOUGH WITH FAIRLY WEAK AND INCONSISTENT
SOUTHERLY FLOW. A MID/UPPER LEVEL SHORT WAVE TROUGH IS EVIDENT
ON WATER VAPOR IMAGERY APPROACHING FROM THE NW...PROVIDING
SUPPORT TO A LARGE AREA OF MODERATE TO STRONG CONVECTION AROUND
A 1007 MB SURFACE LOW CENTERED NEAR 06N116W. GUIDANCE INDICATES
THIS LOW PRES WILL WEAKEN AND DISSIPATE THROUGH 48 TO 72 HOURS
AS IT DRIFTS W...AND AS THE SUPPORTING UPPER DYNAMICS SHIFT
EAST. BY THURSDAY...GUIDANCE IS IN GOOD AGREEMENT SHOWING
ANOTHER 1007 MB LOW PRES SE OF THE GULF OF TEHUANTEPEC...LIKELY
INFLUENCED BY THE SAME MID/UPPER DYNAMICS APPROACHING THE AREA
CURRENTLY.

A few GFS ensembles do deepen this slightly, but not even the CMC shows it. I guess it bears watching though.

Wonder why the models are quiet.

That area Cycloneye showed is where the GFS was showing development if I'm not mistaken.