Atlantic Tropical Action 2014

[Ed Lizard]

Euro does have lower pressures (1005 mb) in the BoC, but with heavy rains displaced well East of the lower pressure.  Not a closed low, either.

 

But beginning of June, and we have had abundant non-tropical rain IMBY, no worries.

[phil882]

The ECMWF and GFS now both have a dual low solution, which feels very reminiscent to Ingrid and Manual last year!

 

 

Day 6 ECMWF from the 1200 UTC run.

 

[Ground Scouring]

In other news, the NHC has launched its own blog:

 

http://noaanhc.wordpress.com

 

We'll be using "Inside the Eye" to communicate important changes about NHC products, talk about how to interpret our products, and discuss topics related to tropical and marine-related weather.

Come take a look at our first post, "The View from Inside the Eye," and be on the look out for additional posts in the coming weeks. On the bottom of the blog page, you can even sign up to receive an e-mail when a new post is made.

 

[wxmx]

The ECMWF and GFS now both have a dual low solution, which feels very reminiscent to Ingrid and Manual last year!

 

 

 

Day 6 ECMWF from the 1200 UTC run.

 

 

That gyre and the associated TCs brought the wettest days on record for the country as a whole. It might not be that extreme this time, but it looks like MX below the Tropic of Cancer will be under the gun for the next couple of weeks.

[Mike.Ventrice]

This feed backs to the upcoming gyre event and associated tropical cyclogenesis/model differences: 

 

https://twitter.com/WSI_Energy/status/472361657172512768

[wxmx]

The operational models are closer to each others solutions...favoring EPac development first, then moving the more favorable upper level dynamics to the GoM, and trying to develop something there as well. Sounds plausible, but any unforeseen stronger development in the EPac would hinder the probabilities of cyclogenesis on the GOM side...and that's something that happens quite frequently.

[Ed Lizard]

The GFS has a sheared look, although a quick check on upper winds doesn't look all that hostile.

 

There is a PW gradient across what the GFS develops, and I suspect abnormally cold waters in the NW Gulf from the brutally cold Texas Winter and rather cool Spring may inhibit storms from forming on the West side of the system and moistening the atmosphere.  Only chance for anything meaningful would be a track Northeast towards Florida.

 

 

 

[phil882]

This feed backs to the upcoming gyre event and associated tropical cyclogenesis/model differences: 

 

https://twitter.com/WSI_Energy/status/472361657172512768

 

 

The operational models are closer to each others solutions...favoring EPac development first, then moving the more favorable upper level dynamics to the GoM, and trying to develop something there as well. Sounds plausible, but any unforeseen stronger development in the EPac would hinder the probabilities of cyclogenesis on the GOM side...and that's something that happens quite frequently.

 

It seems the GEFS aggress with the operational run.

 

 

[LouWX]

It seems the ECMWF and GFS are going opposite directions RE: So. Gulf development next week. 12Z ECMWF through 156HR keeps the system in the BOC (arguably farther SW than the 0Z run) while the GFS is much farther east.

 

NHC seems to want to back the ECMWF solution at this point, which may be a good call considering the GFS has somewhat weakened its once aggressive solutions.

[Ground Scouring]

It seems the ECMWF and GFS are going opposite directions RE: So. Gulf development next week. 12Z ECMWF through 156HR keeps the system in the BOC (arguably farther SW than the 0Z run) while the GFS is much farther east.

 

NHC seems to want to back the ECMWF solution at this point, which may be a good call considering the GFS has somewhat weakened its once aggressive solutions.

Where has the GFS weakened its solution? Comparison between 00Z and 12Z operational runs (00Z 05 May) shows a stronger low, though at a location much farther SW (well into the BOC) than at 00Z. However, the 12Z GEFS shows more of a spread among the ensemble members than at 00Z previously. Please clarify what you are referring to. Maybe I'm missing something. (The ECMWF stalls the low in the BOC days 6-7 before taking the sheared system toward LA on days 8-9.)

[LouWX]

Where has the GFS weakened its solution? Comparison between 00Z and 12Z operational runs (00Z 05 May) shows a stronger low, though at a location much farther SW (well into the BOC) than at 00Z. However, the 12Z GEFS shows more of a spread among the ensemble members than at 00Z previously. Please clarify what you are referring to. Maybe I'm missing something. (The ECMWF stalls the low in the BOC days 6-7 before taking the sheared system toward LA on days 8-9.)

I was referring to the long term trend. Recall the Honduras wave it spun into a moderate TS for many consecutive runs.

[icebreaker5221]

18Z GFS brings back memories of Andrea on her 1-year anniversary

 

Actually, bump this forecast just a hair north, a touch deeper, and slightly larger precip shield and you've got Andrea II. 

 

[Hurr_Tracker13]

The past two runs of the GFS have been interesting to say the least...

[Ground Scouring]

The 12Z operational GFS develops a low in the BOC in just less than four days (hr. 90) and shows a steadily deepening system (1005 to 999 mb in two days) taking a consistent track NE across the northern Yucatán two days later. The fact that the model now latches onto a low center in the BOC, closer to where the ECMWF had previously developed the low (though still to its eastern flank), makes recent GFS solutions more credible. The key to the track and intensity may lie in how the models handle the cutoff low that is to merge with a shortwave stream off the Eastern Seaboard in four days. The ridge that builds in its wake could keep the system farther south in the BOC, or more of a weakness could allow more poleward movement into a more hostile upper-level environment.

[Ground Scouring]

The 12Z operational GFS develops a low in the BOC in just less than four days (hr. 90) and shows a steadily deepening system (1005 to 999 mb in two days) taking a consistent track NE across the northern Yucatán two days later. The fact that the model now latches onto a low center in the BOC, closer to where the ECMWF had previously developed the low (though still to its eastern flank), makes recent GFS solutions more credible. The key to the track and intensity may lie in how the models handle the cutoff low that is to merge with a shortwave stream off the Eastern Seaboard in four days. The ridge that builds in its wake could keep the system farther south in the BOC, or more of a weakness could allow more poleward movement into a more hostile upper-level environment.

The 18Z GFS has definitely trended toward the bolded (latter) scenario, with the low getting sheared apart in the eastern Gulf. Typical middling early-June system. Next, please!

[icebreaker5221]

The 18Z GFS has definitely trended toward the bolded (latter) scenario, with the low getting sheared apart in the eastern Gulf. Typical middling early-June system. Next, please!

 

  18Z GFS scenario is certainly a possibility, but you've got to see the humor in calling next based on a 7-day GFS forecast for a system that doesn't even have an invest yet!

[Ground Scouring]

18Z GFS scenario is certainly a possibility, but you've got to see the humor in calling next based on a 7-day GFS forecast for a system that doesn't even have an invest yet!

Maybe "next" was overkill / hyperbole (after the last several Atlantic seasons, it's understandable), but even if this hypothetical system were to develop, nothing in the most aggressive of the reliable models (GFS) has indicated anything stronger than a weak to moderate TS. We will need to see big changes in the environment to get conditions reasonably favorable for a strong TS or minimal hurricane. So far nothing indicates anything worth watching from a chasing standpoint. Of course we still need an actual INVEST first, but again, so far, it's nothing big. But I'll retract the "next" as over-the-top hyperbole. Still, something in the first week of June is better than nothing, I suppose.

[phil882]

C'mon guys, you can't get caught up in the run to run discontinuity that is going on trying to identify which spokes of vorticity are going to become dominant when they haven't even developed yet. The key thing here is that it appears a very large scale gyre circulation will be evolving over Central America the next 3-5 days and whether or not it results in the development of a weak, sheared tropical cyclone remains to be seen.

 

Obviously the system in the EPAC has the best chance at becoming a significant TC because its under the most favorable conditions and is mainly embedded in a barotropic environment with an outflow channel attempting to develop in response to the equatorward moving upper-level trough. Anything that gets into the Gulf of Mexico will not be fully tropical in nature due to the strong baroclinicity of the environment in the mid-upper levels producing strong vertical wind shear. That doesn't mean we can't get a hybrid tropical cyclone out of this, but it probably means don't have high expectations for anything considered "chasable."

[hurricaneman]

seems a little more robust in the 0zGFS as it forms a TS around Thursday afternoon and deepens it to 998 MB by 204 hrs near the NE tip of the Yucatan and makes landfall as a moderate TS near Tampa at 240 but as I see it the last 2 parts of this post should be taken with a grain of salt while sometime this week we could be looking at the first named storm of 2014

[hurricaneman]

Seems as though the Epac system may cross over and possibly be more of a threat to areas in the BOC and possibly the ne gulf coast and maybe even the east coast if the GFS is right and IMO it seems as though the Euro is trending to the GFS so we'll have to wait and see

[wxmx]

Models are already spitting out 15"+ of precip for some areas in MX around the BoC and Tehuantepec. This is going to be mostly a rainmaker. All models keep a ridge over Nern MX extending to the NW GoM for the medium range, and are less enthustiastic with the sweeping trough over the Plains and S CONUS. Any disturbance in the BoC will be a slow mover, probably crawling WNW. The Euro and GEM are stronger with the ridge, forecasting the disturbance landfalling in NE MX...very weak. The GFS has been slower with motion, and it keeps it meandering in the BoC for several days. Models are also focusing on a wave coming onto stage in the medium range as well (6+ days), from the NE Caribbean into the GoM.

 

My take on this is leaning towards the Euro, with a weak low (TD/low end TS) trekking very slowly WNW and making landfall near the Tampico area around day 5. There's much more uncertainty about the second wave, since it's still far ahead in time. The Euro moves it into the Tampico area as a very weak disturbance...the GFS has been very adamant on stalling it near the Yucatan Nern tip and then recurving NE towards the SW Florida. I would favor the latter scenario, but my confidence of cyclogenesis and path is very low.

[Srain]

RECON may fly down Bay of Campeche and take a look in a couple of days. One thing that these BoC monsoonal gyres offer is a lot of uncertainty and a challenging forecast. A sheared mess but a big rain maker could be ahead along the Gulf Coast regardless of development.  If the upper ridge does shift W as the next trough drops into the Plains, the potential increases along the NE Mexico /NW and Central Gulf.

[Srain]

The NHC has declared the area of disturbed weather along a trough in the Bay of Campeche as 90L. The purpose is likely to begin running the various models to see is anything may develop over the next several days.

 

...DISCUSSION...

GULF OF MEXICO...                                              
AN ELONGATED MIDDLE LEVEL TROUGH OVER THE BAY OF CAMPECHE
CONTINUES TO SUPPORT A SURFACE TROUGH OF LOW PRESSURE FROM
24N92W TO A 1006 MB LOW NEAR 20N94W TO 18N94W. THIS AREA OF LOW
PRESSURE IS GENERATING CLOUDINESS ACROSS MUCH OF THE GULF AS
WELL AS SCATTERED MODERATE CONVECTION E OF A LINE FROM 28N85W SW
TO 21N97W. CHANCES THIS SYSTEM DEVELOP INTO A TROPICAL CYCLONE
WITHIN THE NEXT 48 HOURS REMAIN LOW...HOWEVER LOCALLY HEAVY
RAINFALL IS POSSIBLE FOR THE SW BASIN AS WELL AS PORTIONS OF SE
MEXICO TO INCLUDE THE YUCATAN PENINSULA. A BROAD UPPER RIDGE
COVERS THE CENTRAL AND SE CONUS AS WELL AS THE FAR W ATLC. THE
RIDGE ALOFT SUPPORTS A SURFACE RIDGE OVER THE SW N ATLC ANCHORED
BY A 1017 MB HIGH NEAR 30N83W WHICH EXTENDS AN AXIS INTO THE NE
GULF AND PROVIDES E-SE FLOW OF 5-15 KT OVER THE EASTERN AS WELL
AS THE NW GULF. THE AREA OF LOW PRESSURE OVER THE SW GULF IS
FORECAST TO PERSIST THROUGH FRIDAY WHILE WEAK SURFACE RIDGING
WILL DOMINATE ELSEWHERE.

 

[Ground Scouring]

The GFS, which has consistently overplayed the short-term development prospects, has significantly tempered its prospects, intensity wise, for the BOC low. This is consistent with the ECMWF's repeated downplaying of development over the past several days. Any development, if at all, looks to occur in more than a week, and since the most reliable models (of which the GFDL is not one) are not aggressive I don't think it will happen. Conditions just look too hostile.

[ohleary]

The NHC has declared the area of disturbed weather along a trough in the Bay of Campeche as 90L. The purpose is likely to begin running the various models to see is anything may develop over the next several days.

 

...DISCUSSION...

GULF OF MEXICO...                                              

AN ELONGATED MIDDLE LEVEL TROUGH OVER THE BAY OF CAMPECHE

CONTINUES TO SUPPORT A SURFACE TROUGH OF LOW PRESSURE FROM

24N92W TO A 1006 MB LOW NEAR 20N94W TO 18N94W. THIS AREA OF LOW

PRESSURE IS GENERATING CLOUDINESS ACROSS MUCH OF THE GULF AS

WELL AS SCATTERED MODERATE CONVECTION E OF A LINE FROM 28N85W SW

TO 21N97W. CHANCES THIS SYSTEM DEVELOP INTO A TROPICAL CYCLONE

WITHIN THE NEXT 48 HOURS REMAIN LOW...HOWEVER LOCALLY HEAVY

RAINFALL IS POSSIBLE FOR THE SW BASIN AS WELL AS PORTIONS OF SE

MEXICO TO INCLUDE THE YUCATAN PENINSULA. A BROAD UPPER RIDGE

COVERS THE CENTRAL AND SE CONUS AS WELL AS THE FAR W ATLC. THE

RIDGE ALOFT SUPPORTS A SURFACE RIDGE OVER THE SW N ATLC ANCHORED

BY A 1017 MB HIGH NEAR 30N83W WHICH EXTENDS AN AXIS INTO THE NE

GULF AND PROVIDES E-SE FLOW OF 5-15 KT OVER THE EASTERN AS WELL

AS THE NW GULF. THE AREA OF LOW PRESSURE OVER THE SW GULF IS

FORECAST TO PERSIST THROUGH FRIDAY WHILE WEAK SURFACE RIDGING

WILL DOMINATE ELSEWHERE.

 

 

 

Just one last run for Boris at 12Z today.  At 10% and the NAM and globals doing nothing with it, I'll be surprised for them to request hur model runs unless something changes...but I've been wrong before (once).

[phil882]

Of course it doesn't matter if the system develops or not, this is causing very heavy rainfall over Central America and likely will continue doing so for at least the next 3-5 days if the GFS and ECMWF are correct. We tend to focus on whether or not a TC develops, but this might be one of those cases a disturbance causes a large loss of life due to massing flooding, mudslides ect even though it is not formally recognized as a tropical cyclone.

[phil882]

Looks like a closed circulation is attempting to develop in the Gulf of Mexico.

 

[wxmx]

Yes, it appears a low/mid level low is evident on vis imagery and it probably is trying to close off a surface low. Like it has been noted before, upper levels winds look hostile and with no sign to abate any time soon.

[phil882]

Yes, it appears a low/mid level low is evident on vis imagery and it probably is trying to close off a surface low. Like it has been noted before, upper levels winds look hostile and with no sign to abate any time soon.

 

But that same upper-level vertical wind shear is also providing upper-level diffluence which is likely enhancing the convection in the first place.

 

Now I'm not arguing for a robust TC out of this, but its entirely something marginal (TD or minimal TS strength) developing briefly in the Bay of Campeche the next 24-36 hours (and I think probabilities should be higher than the 20% the NHC is currently prescribing). Vertical wind shear has its strongest detrimental effect when its also coupled with dry mid-level air, and one thing 90L has going for it is that it is embedded in a very high precipitable water environment. This will limit the negative effects of shear somewhat. The biggest problem 90L might have is proximity to land, with the ECMWF suggesting it moves inland before any consequential development can take place. 

 

The gyre system I have been discussing isn't likely to go away in the near future though, and this is why this system poses a very dire flooding threat for Central America and Mexico. Both the GFS and ECMWF suggest this disturbance remaining over Central America for at least the next 5 days (with the ECMWF suggesting it could emerge in the Gulf of Mexico again as a closed low-level circulation again in the day 8-10 range). These events often don't really get the respect they deserve because they are "boring" only producing torrential rain and substantial loss of life due to freshwater flooding. However, if enough of the circulation remains over water, I think some more TC related can come out of it as well.  

 

I think we all learned last year that it doesn't take very much to spin something up in the Bay of Campeche, and Berry, Fernand, TD#8, Ingrid should have taught us the global models can provide hints, but seldom do a great job in this region. Especially when you smaller system embedded in larger-scale vorticity, you have to watch out for unexpected vortex stretching that sets TCG in motion. 

[Srain]

But that same upper-level vertical wind shear is also providing upper-level diffluence which is likely enhancing the convection in the first place.

 

Now I'm not arguing for a robust TC out of this, but its entirely something marginal (TD or minimal TS strength) developing briefly in the Bay of Campeche the next 24-36 hours (and I think probabilities should be higher than the 20% the NHC is currently prescribing). Vertical wind shear has its strongest detrimental effect when its also coupled with dry mid-level air, and one thing 90L has going for it is that it is embedded in a very high precipitable water environment. This will limit the negative effects of shear somewhat. The biggest problem 90L might have is proximity to land, with the ECMWF suggesting it moves inland before any consequential development can take place. 

 

The gyre system I have been discussing isn't likely to go away in the near future though, and this is why this system poses a very dire flooding threat for Central America and Mexico. Both the GFS and ECMWF suggest this disturbance remaining over Central America for at least the next 5 days (with the ECMWF suggesting it could emerge in the Gulf of Mexico again as a closed low-level circulation again in the day 8-10 range). These events often don't really get the respect they deserve because they are "boring" only producing torrential rain and substantial loss of life due to freshwater flooding. However, if enough of the circulation remains over water, I think some more TC related can come out of it as well.  

13 years ago a weak bad looking TS spun up 80 miles S of Galveston. TS Allison, now retired remains the costliest TS affecting the US to date causing over 5 billion in damage and claiming 22 lives as well as 5 days of meandering around Metro Houston.

 

http://vimeo.com/65510993