Atlantic Tropical Action 2014

[Ground Scouring]

Not exactly what you asked for, but it may help:

 

http://rammb.cira.colostate.edu/projects/gparm/data/archived/

That doesn't have the data for 2012-2013, so for the purpose of my analysis it wouldn't work.

[wxmx]

That doesn't have the data for 2012-2013, so for the purpose of my analysis it wouldn't work.

It does, it just has the wrong links

 

http://rammb.cira.colostate.edu/projects/gparm/data/archived/2012/index.html

http://rammb.cira.colostate.edu/projects/gparm/data/archived/2013/index.html

[Santa Claus]

There looks like some kind of elongated circulation over Louisiana.  Get a plane in there! 

[Ground Scouring]

It does, it just has the wrong links

 

http://rammb.cira.colostate.edu/projects/gparm/data/archived/2012/index.html

http://rammb.cira.colostate.edu/projects/gparm/data/archived/2013/index.html

Thanks. I see that in July 2011, 2012, and 2013, the shear abruptly stopped decreasing and then increased through August/September. (This pattern did not exist from 2000-2005, but started showing up with increasing frequency starting in 2006.) We are seeing the same thing happening now with the ECMWF showing many more TUTTs over the coming week than in the previous weeks so far this month and in June 2014. As I have mentioned previously, I think the forecasts for lower-than-average shear in the MDR are going to bust, perhaps badly. It is interesting to note that the shear increase coincides exactly with the decreased precipitation that bluewave has posted about. Are the two linked? 

 

 

[Sunny and Warm]

 

Thanks. I see that in July 2011, 2012, and 2013, the shear abruptly stopped decreasing and then increased through August/September. (This pattern did not exist from 2000-2005, but started showing up with increasing frequency starting in 2006.) We are seeing the same thing happening now with the ECMWF showing many more TUTTs over the coming week than in the previous weeks so far this month and in June 2014. As I have mentioned previously, I think the forecasts for lower-than-average shear in the MDR are going to bust, perhaps badly. It is interesting to note that the shear increase coincides exactly with the decreased precipitation that bluewave has posted about. Are the two linked? 

 

 

 

Roughly equates to the change in the long term PDO signal.

[Ground Scouring]

Roughly equates to the change in the long term PDO signal.

Nonsense…the PDO was just as negative during the 1940s-1950s and the precip. signal was the complete opposite over the MDR. (See bluewave's post above.) I can also think of -PDO regimes during the late 19th century that also featured much higher precip. over the MDR. Clearly the atmosphere is much too complex to respond in a linear fashion to one factor.

[Sunny and Warm]

Nonsense…the PDO was just as negative during the 1940s-1950s and the precip. signal was the complete opposite over the MDR. (See bluewave's post above.) I can also think of -PDO regimes during the late 19th century that also featured much higher precip. over the MDR. Clearly the atmosphere is much too complex to respond in a linear fashion to one factor.

My point was not nonsense in that I was correct in saying that the PDO signal changed in that time period, but your point is well taken that some other factor(s) may be in play.   There are better ways to get your point across without castigating other posters.

[Floydbuster]

The back and forth of this season is amazing. One week it looks like a Super El Nino and slower than 2013, the next week it looks like it'll expode in mid-August and it could be a big season.

[phil882]

Even though the remnants of TD#2 don't have a closed earth relative circulation anymore, an argument could be made that a storm-relative circulation still exists based on radar out of the Barbados.

 

http://www.barbadosweather.org/barbados-weather-Radar-SABDriver.php

 

 

[hurricaneman]

We may see the MJO start to go favorable by the beginning of next month which also agrees with the euro which the GFS doesnt do so if I were to go with one in this case it would be the Euro since the GFS has been awful with for many years the propagation of the MJO and this might bring up the vertical instability closer to normal levels but then again who knows

 

http://www.cpc.ncep.noaa.gov/products/people/wd52qz/mjo/chi/ewp.gif

[Sunny and Warm]

We may see the MJO start to go favorable by the beginning of next month which also agrees with the euro which the GFS doesnt do so if I were to go with one in this case it would be the Euro since the GFS has been awful with for many years the propagation of the MJO and this might bring up the vertical instability closer to normal levels but then again who knows

 

http://www.cpc.ncep.noaa.gov/products/people/wd52qz/mjo/chi/ewp.gif

Not disagreeing that the Euro is more correct than the GFS when it comes to the MJO, but if I recall, the Euro was too robust with the most recent MJO propagation forecast.

[Ground Scouring]

My point was not nonsense in that I was correct in saying that the PDO signal changed in that time period, but your point is well taken that some other factor(s) may be in play.   There are better ways to get your point across without castigating other posters.

I actually never said you were wrong about the PDO change…I only said the idea that the PDO change = increased shear (since in fact a -PDO often means less shear and is correlated with cool ENSO, meaning more favorable conditions in the Atlantic) was "nonsense." And I will admit that I came across as being harsh; I should have worded my post differently. But so far I have not seen a convincing explanation as to why we've seen so much shear in the MDR recently. Claims about the PDO can be easily disproven by looking at other -PDO periods in which precip. in the MDR was much higher than it is now. HM hasn't been around recently, but I'm sure that he can address the points I've raised in my posts re: the TUTT pattern in the Atlantic. The +IO signal, if I recall correctly, enhances rather than weakens the Hadley cell, so that the +IO would explain the Atlantic dryness but not the increase in TUTTs, but I could be wrong. This area really needs more study, and I wish that someone could answer my questions about what might be causing the TUTT pattern.

 

As an aside, the Indian Ocean has cooled quite a bit in the past few weeks. Combined with the cooling subsurface in the NINO zones, this trend, if sustained through mid to late August, could help to increase instability in the MDR. The last several seasons featured a +IO signal in time for peak season; this year the signal is still + but is trending cooler with time. That's a difference that could be important for instability, since El Niño seems increasingly unlikely to affect the peak of this season come late August/early September.

[Wannabehippie]

The back and forth of this season is amazing. One week it looks like a Super El Nino and slower than 2013, the next week it looks like it'll expode in mid-August and it could be a big season.

Isn't there an awful lot of SAL to get rid of, even if the shear lessens?

 

http://tropic.ssec.wisc.edu/real-time/salmain.php?prod=splitEW

[thewxmann]

The back and forth of this season is amazing. One week it looks like a Super El Nino and slower than 2013, the next week it looks like it'll expode in mid-August and it could be a big season.

 

says who?

[hurricaneman]

The GFS the last few runs has been trying to do something similar to TD2 and pinch off a piece of vorticity from the ITCZ but the most recent run has the Lesser Antilles in its crosshairs around 180hrs so this may need to be watched as the MJO moves towards the atlantic

[phil882]

The GFS the last few runs has been trying to do something similar to TD2 and pinch off a piece of vorticity from the ITCZ but the most recent run has the Lesser Antilles in its crosshairs around 180hrs so this may need to be watched as the MJO moves towards the atlantic

 

Yep. The NHC has noted this too in their most recent TWO (20% in five days). I think they want to do a better job of not getting caught flat footed by the GFS like they did last week. 

 

 

I definitely wouldn't sleep on this possibility... the ECMWF, while not developing a TC, has had a similar like pattern where a nice monsoon trough stretches out to 30-40 W and attempts to develop a TC in the medium range (day 3-5). The upper-level flow has also become more favorable as the Mid-Ocean Trough (MOT), which had been producing significant westerlies near the lesser antilles has backed off a little further west. We shouldn't see the same scenario as we saw with TD#2, with the ECMWF, despite not developing a TC, does show a widespread area of upper-level easterly flow across the MDR by 180 hours.

 

 

If this period of more favorable upper-level flow also coincides with MJO entering phases 1-3 (as the ECMWF suggests), this could result in more TC activity in the MDR the first couple of weeks of August. Maybe some things to look forward to despite the bleak outlook.

 

[Superstorm93]

 

 

SYNOPSIS 2014072500

P08L

9N, 2W

700 hPa

Initiating P08L based upon forecasts of a pouch emerging from Africa in about four days; however, the fields do not depict a pouch for much of the first few days, so early positions are incredibly uncertain.

ECMWF: A pouch is not depicted until 120 hours, so all previous positions are very uncertain.

GFS: A distinct pouch with a CL-trough intersection is over west Africa for the first 36 hours, but it then weakens considerably on Day 2. By 84 hours, a pouch is spinning up off of Africa.

UKMET: Similar to GFS, with a strong pouch developing after 72 hours.

NAVGEM: Slower phase speed. Weaker pouch in the analysis, but similar to GFS & UKMET with a strengthening pouch after 72 hours.

 

[phil882]

Make that two TCs from the latest GFS (with a third one attempting to develop at the end of the forecast period before truncation). Even if all of these are fantasy systems, its a sign that the global models are forecasting more favorable conditions in the MDR in the medium range.

 

 

 

 

Now if we could only get the ECMWF to come onboard, which has been more pessimistic with TCG, although its depicting similar more favorable upper-level flow. 

[Ground Scouring]

Doesn't the ECMWF show a train of upper lows in the central Atlantic (like the ones we've seen in the past week and a half) in the medium to long range? I'm pretty skeptical about the more favorable upper-air environment. As an aside, unless they have good meteorological basis for doing so, I would politely suggest that some members read more/post less before jumping the gun on an active season.

[phil882]

Doesn't the ECMWF show a train of upper lows in the central Atlantic (like the ones we've seen in the past week and a half) in the medium to long range? I'm pretty skeptical about the more favorable upper-air environment. As an aside, unless they have good meteorological basis for doing so, I would politely suggest that some members read more/post less before jumping the gun on an active season.

 

The map below is from the ECMWF in the medium range. There is one TUTT feature located around 35N 50W, but this is poleward of where most of the TUTTs have been propagating along the MOT thus far. Note the 200-hPa ridge dominating the MDR with easterlies extending into the Caribbean. The ECMWF has also been forecasting the MJO to be in phases 1-3 beyond 5 days, which are typically phases associated with increased Atlantic TC activity. Its been mentioned previously that the intraseasonal state can overcome the longer-range intraannual atmospheric ENSO state. Whether or not this translates to increased activity this go around (or if the MJO does propagate as the models are forecasting) remains to be seen, but there is reason for optimism. 

 

[Ground Scouring]

The map below is from the ECMWF in the medium range. There is one TUTT feature located around 35N 50W, but this is poleward of where most of the TUTTs have been propagating along the MOT thus far. Note the 200-hPa ridge dominating the MDR with easterlies extending into the Caribbean. The ECMWF has also been forecasting the MJO to be in phases 1-3 beyond 5 days, which are typically phases associated with increased Atlantic TC activity. Its been mentioned previously that the intraseasonal state can overcome the longer-range intraannual atmospheric ENSO state. Whether or not this translates to increased activity this go around (or if the MJO does propagate as the models are forecasting) remains to be seen, but there is reason for optimism. 

Thanks for your response. The ECMWF look is the best early-August pattern I've seen after the past three seasons. It's a big change from recent years, perhaps because the Indian Ocean has cooled off quite a bit in the past month, allowing instability to rise and perhaps affecting the placement of the TUTTs. I know that the following area of research is not your specialty, but since HM isn't around, I would appreciate your thoughts on what is causing the following:

 

http://www.americanwx.com/bb/index.php/topic/42483-atlantic-tropical-action-2014/?p=3010630

 

If we can finally get a pattern where the TUTTs lift north in prime time (latter August/earlier September), then the odds of a significant TC hitting the U.S. will be quite good, as virtually all the long-range guidance shows a strong, west-based Bermuda High (with a west-based -NAO and mean trough in the Midwest, as in 2004) during peak season. Over the next week, the SAL should also be decreasing as the flow off Mauritania shifts more to the N.

[GaWx]

 

If this period of more favorable upper-level flow also coincides with MJO entering phases 1-3 (as the ECMWF suggests), this could result in more TC activity in the MDR the first couple of weeks of August. Maybe some things to look forward to despite the bleak outlook.

 

 

 Phil,

 I agree with your general idea of a valid reason to look for increased genesis chances in early August per the Euro's MJO fcast.. More specifically, I agree with regard to phase 2 and especially phase 3 (and even more with that progged strong amplitude that isn't seen often though it could easily be overdone) though phase 1 seems to be fairly neutral per 1995-2012 August stats. Note that there have been merely two MJO phase 3 days on average in August over the last 20 years. IF this Euro prog is correct, there will be a good week or so or more of phase 3 this August, way over the two day average.

 

 

Aug. geneses 1995-2012 by phase:

MJO phase: MJO # days; # TC geneses/# MDR TC geneses/# US direct H hit TC geneses;      TC geneses per day/MDR TC geneses per day/US direct H hit TC geneses per day

1: 63; 9/5/1;  14%/8%/2% (Bret ’99)

2: 88; 17/8/3; 19%/9%/3% (Isaac ’12, Gustav ’08, Bonnie ’98)

3: 32; 12/8/1; 38%/25%/3% (Fran ’96)

4: 15; 0/0/0; 0%/0%/0%

5: 34; 5/4/0; 15%/12%/0%

6: 36; 7/5/1; 19%/14%/3% (Charley ’04)

7: 14; 1/0/0; 7%/0%/0%

8: 22; 4/2/2; 18%/9%/9% (Frances ’04, Earl ’98)

C: 254; 25/13/2; 10%/5%/1% (Irene ’11, Katrina ’05)

 

ALL: 558; 80/45/10; 14%/8%/2%

-Note the high %'s of both TC geneses and MDR TC geneses for phase 3. Regarding MDR, alone, if the Euro's prog of 7 days in phase 3 were to be correct, that would mean a good bit better than a 50% chance for genesis there based on the 1995-2012 August phase 3 raw data, which suggests a whopping 25% chance of genesis on any one day. Even if that % is overdone due to it not being a huge sample, the idea to watch out then would seem valid.

[Superstorm93]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT SUN JUL 27 2014

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

1. A tropical wave located about 400 miles southwest of the Cape
Verde Islands is moving westward at 10 to 15 mph. Although shower
activity is currently disorganized, environmental conditions are
expected to become conducive for the development of an area of low
pressure over the central tropical Atlantic by the middle of this
week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.

 

[Ground Scouring]

If a depression forms on or before 12Z July 27 (when Alex 1998 formed), in the same general region as the GFS and its ensembles indicate, it would potentially be one of the earliest-forming CV systems on record. Only Bertha 2008 (03 July), Bertha 1996 (05 July), Chantal 2013 (07 July), Dorian 2013 (22 July), and Anna 1969 (25 July) formed earlier in the region within 200 n mi of 10-15° N 40° W. Climatology for this area, limited though it is, suggests that systems tended to recurve after reaching the longitude of the Lesser Antilles, but given the tendency for the GFS to over-amplify troughs at this time of year, any potential system might well end up farther west. Given the strong low-level ridge in place, anything that forms has a good chance to at least reach the islands of the E Caribbean. If any system were to form later and farther west, than the chances of a U.S. impact increase somewhat.

[Superstorm93]

27km Nest of the 2014 HWRF develops the CATL wave into a pretty decent storm. GFS not only still has the storm, but has been getting more bullish over the past few runs. The ECMWF just has a strong wave making its way into the Caribbean. 

 

FY2014 HWRF:

 

[Eyewall2005]

Just one problem..whats been the pattern last few seasons with deep trof of eastcoast should recurve anything out there.

[Kory]

If a depression forms on or before 12Z July 27 (when Alex 1998 formed), in the same general region as the GFS and its ensembles indicate, it would potentially be one of the earliest-forming CV systems on record. Only Bertha 2008 (03 July), Bertha 1996 (05 July), Chantal 2013 (07 July), Dorian 2013 (22 July), and Anna 1969 (25 July) formed earlier in the region within 200 n mi of 10-15° N 40° W. Climatology for this area, limited though it is, suggests that systems tended to recurve after reaching the longitude of the Lesser Antilles, but given the tendency for the GFS to over-amplify troughs at this time of year, any potential system might well end up farther west. Given the strong low-level ridge in place, anything that forms has a good chance to at least reach the islands of the E Caribbean. If any system were to form later and farther west, than the chances of a U.S. impact increase somewhat.

With a deep trough along the East Coast next week, the GFS track looks most plausible.  A track north of the Islands is most likely in my opinion.  

[Superstorm93]

I'd rather see some (relatively) robust MDR TC that heads out to sea as opposed to a sheared mess that crawls through the Caribbean and eventually dissipates. 

[Kory]

I'd rather see some (relatively) robust MDR TC that heads out to sea as opposed to a sheared mess that crawls through the Caribbean and eventually dissipates. 

Yeah, the Caribbean is a wood-chipper.  It has been the most of the season so far with shear consistently 30-40 kts.  

[bluewave]

The Euro is showing the same pattern over the next week that we just saw with the depression.

While we could see a spin up on the ITCZ, it won't have much of a future when it begins

gain latitude and ingest dry air.