Atlantic Tropical Action 2013

[gulfcane]

Verbatim is short hand for, yes, I know a somewhat coarse resolution global will not nail the intensity.  OTOH, the GFS was not without skill during the last TC, either in predicting development nor in predicting its weakening and demise.  I'm rather more concerned with the wide swing between the 6Z GFS, well supported by its ensembles, and the 12Z GFS

 

I'm rather curious what data (there aren't that many sites around the world that do 12Z balloon releases) made it into the 12Z, that neither the 6Z GFS nor 16 or 17 of 20 perturbed members didn't have to produce a rather wide swing.  I've seen it debunked many places that the off run GFS models are just run with the 6 hour forecasts of the previous run and no new data is initialized. 

 

Then again, maybe the Trinidad or Almirante sounding this morning really did make a difference.

 

Edit to Add

 

Quick look at NCEP NWATL 4 panels and PSU four panels may provide one clue why the GFS doesn't spin up a Cat 3 from a tropical depression in the less than 48 hours between the Yucatan and the North Central Gulf.  Potential system is inside a narrow corridor of >70% mean 700-500 mb RH, or dry air issues may counter favorable shear and OHC.

I would have to go back and pull up the saved images for the proof, but the GFS for days had a well developed strengthening tropical cyclone passing north of PR and continuing to intensify through the Bahamas. This was about a 7 day forecast, similar to the timefram here. The GFS subsequently dropped this idea once it switched to the supercomputer (although the underlying physics remained the same as the old computer). So yes, if you ignore the days and days that the GFS had Dorian strengthening and focus only on its performance subsequent to that, it did perform well. We'll have to check back in 1 week and see if we score it for the GFS and it never drops below about 1000mb, or if that solution turned out to be unreasonable for mid August in the GOM.

[Ed Lizard]

Canadian should have similar dry air issues based on PSU 4 panel as GFS, despite different track.  Fairly narrow North-ish to South-ish oriented ribbon of >70% mean 700-500 mb RH follows its storm. 

 

I was fooled briefly by using FSU site 700 mb theta-e as a stand in for RH.  I thought Canadian was moistening its own environment, actually its stronger system was just developing more of a warm core.  Or, display resolution on PSU 4 panel tropical models far inferior to FSU site, but having four panels makes it easier to see what is going on for this hobbyist.

[am19psu]

Look, the models aren't perfect. They blew the intensity forecast for Utor in the Philippine Sea. But you're going to do better trusting their depiction of the environment than relying on climo. Now, if you were to argue that they are poorly handling the MJO/CCKW or something, I'd tend to believe an argument for why the model is wrong compared to just "climo" in the Gulf, as if a 45 kt TS has never made landfall in late August

[Ed Lizard]

I would have to go back and pull up the saved images for the proof, but the GFS for days had a well developed strengthening tropical cyclone passing north of PR and continuing to intensify through the Bahamas. This was about a 7 day forecast, similar to the timefram here. The GFS subsequently dropped this idea once it switched to the supercomputer (although the underlying physics remained the same as the old computer). So yes, if you ignore the days and days that the GFS had Dorian strengthening and focus only on its performance subsequent to that, it did perform well. We'll have to check back in 1 week and see if we score it for the GFS and it never drops below about 1000mb, or if that solution turned out to be unreasonable for mid August in the GOM.

 

Unpredictability on the GFS, indeed.  6Z and 12Z.  I remember the sudden shift when computers were changed.  In fact, a degreed (PSU!) met had a theory NCEP slipped something into the code secretly to correct GFS 'physics problem handling the heat' and keep storms from re-curving prematurely.  But based on both Canadian and GFS (Canadian dry air issues don't impede intensification) and less than 2 days over water, at least based on its track and intensity, GFS is probably ballpark if its track is close.  BTW, maybe Larry knows what climo intensification rate per day or hour (knots, mb) for the Central Gulf in mid August.  I don't. 

[andyhb]

The GFS has no skill at forecasting tropical cyclone intensity. In fact, the NHC had no skill at predicting tropical cyclone intensity at days 2, 3, 4, and 5 in 2012. Best to go with climatology in this case which would favor a TS being able to strengthen into a hurricane in the GOM in mid August. 1006mb max intensity per GFS is unreasonable.

 

Based on what? All that is seen here is an absolute statement that really has no business being made right now.

 

The GFS' resolution sometimes causes it to aim too high with pressures, but I don't think this is really the situation in this case. And lol at the NHC call out.

[Superstorm93]

Bendy Mod's renewed presence terrifies me, but at the risk of being scolded here, I'll do a simple analysis of the 12z GFS and throw in a dash of opinion. 

 

So it appears that a tropical wave starts to get its act together just NE of central America by 72 hours. By that time, hopefully the system is an invest because I am particularly interested in the intensity forecast for this potential system. As the wave tracks through the western Caribbean, it will be encountering a truly unholy amount of TCHP and somewhat favorable upper level conditions. If our tropical wave surprises us and develops into a strong low or even a depression before reaching the Yucatan, I wouldn't rule out a tropical storm entering the Gulf by say, 120 hours or so. This would make for an interesting week, but it's extremely unlikely until we have more than just the GFS and a few weenie models picking this up.  

 

At that point, the GFS (verbatim) has a developing system under a large anticyclonic flow, with some very impressive heat potential just north of the Yucatan. After that, the steering currents become rather uncertain so I'm not even going to touch upon that. 

 

All in all, at least we have something to watch, and hopefully the NHC starts to mention the possibility of 5 day development in the TWO soon. 

 

 

Anticyclone in place by 120 hours 

 

[am19psu]

Lol. Don't be terrified of me. That's good analysis. You've highlighted a plausible scenario and backed up your ideas. I don't ask for much than that.

[Sunny and Warm]

Lol. Don't be terrified of me. That's good analysis. You've highlighted a plausible scenario and backed up your ideas. I don't ask for much than that.

that was darn good analysis, I agree.  Very similar to my thinking as I looked at Ed's spaghetti loops (don't say anything).  Something starts to wind up off Belize and continues in the BOC.  Beyond that, I have no idea where it goes, but I suspect more north than west.

[gulfcane]

Based on what? All that is seen here is an absolute statement that really has no business being made right now.

 

The GFS' resolution sometimes causes it to aim too high with pressures, but I don't think this is really the situation in this case. And lol at the NHC call out.

 

Too high with pressures? How about too high, too low, and everything in between. I guess when the model spits out every solution possible, it's supporters can point to the runs showing the correct solution as evidence the model has skill forecasting intensity. Just because it covers all possible intensities by spitting a new solution out every run does not mean the model has skill. Below is your 6 day GFS forecast for Dorian. This run of the GFS would go on to strengthen Dorian to about 975mb off the NC coast. Had the same solution for many runs. Showed category 5 hurricanes Dean and Felix as broad area of low pressures a few years ago. There are many, many, more recent examples besides those. Go read the NHC post season analysis for any year and you will see just what I am talking about. You're probably about to get another case study this week which will save you some time. As far as the "NHC call out" go to page 63.....http://www.nhc.noaa.gov/verification/pdfs/Verification_2012.pdf

There was no skill at forecasting intensity at days 2, 3, 4, and 5. Accoding to the NHC report page 15....the GFS intensity forecast is "typically not considered by forecasters". Hmmm maybe because it has no skill at forecasting intensity? It is quite frankly hard to understand why people can not accept this fact. Thankfully the NHC does, and it's nothing personal. It is simply fact.

[andyhb]

Too high with pressures? How about too high, too low, and everything in between. I guess when the model spits out every solution possible, it's supporters can point to the runs showing the correct solution as evidence the model has skill forecasting intensity. Just because it covers all possible intensities by spitting a new solution out every run does not mean the model has skill. Below is your 6 day GFS forecast for Dorian. This run of the GFS would go on to strengthen Dorian to about 975mb off the NC coast. Had the same solution for many runs. Showed category 5 hurricanes Dean and Felix as broad area of low pressures a few years ago. There are many, many, more recent examples besides those. Go read the NHC post season analysis for any year and you will see just what I am talking about. You're probably about to get another case study this week which will save you some time.

 

Except the fact that most models have problems with TC intensities at 147 hrs out. And using Felix and Dean as examples probably isn't the best bet either since 1) those were 6 years ago and 2) something about me doubts any model really picked up very well on the intensities of those storms, particularly in Felix's case (if you can show me graphics prior to that stage, then all the more power to you).

 

Also you still called out the NHC for poor intensity forecasts and haven't offered any support for that, especially when it is known that TC intensity forecasting is not the most exact science.

 

Edit: I see your edit and I think my point still stands.

[Srain]

Too high with pressures? How about too high, too low, and everything in between. I guess when the model spits out every solution possible, it's supporters can point to the runs showing the correct solution as evidence the model has skill forecasting intensity. Just because it covers all possible intensities by spitting a new solution out every run does not mean the model has skill. Below is your 6 day GFS forecast for Dorian. This run of the GFS would go on to strengthen Dorian to about 975mb off the NC coast. Had the same solution for many runs. Showed category 5 hurricanes Dean and Felix as broad area of low pressures a few years ago. There are many, many, more recent examples besides those. Go read the NHC post season analysis for any year and you will see just what I am talking about. You're probably about to get another case study this week which will save you some time.

 

 

Let`s look at the NCEP Ensemble TC Genesis Probs for Dorian. The ensembles were correct with sniffing genesis and also correct with the demise of Dorian.If you recall the operational Euro and its ensembles were no where close to be correct with TC genesis. The point being is the computer models are called "guidance", not absolutes. Let us also not forget the Debby debacle last year.

 

 

 

[gulfcane]

Except the fact that most models have problems with TC intensities at 147 hrs out. And using Felix and Dean as examples probably isn't the best bet either since 1) those were 6 years ago and 2) something about me doubts any model really picked up very well on the intensities of those storms, particularly in Felix's case (if you can show me graphics prior to that stage, then all the more power to you).

 

Also you still called out the NHC for poor intensity forecasts and haven't offered any support for that, especially when it is known that TC intensity forecasting is not the most exact science.

I edited it while you were responding. Please go re-read my post. The support I provided for the poor NHC intensity forecast was the NHC's very own verification report. Go back and look at the post. The GFS has no skill at forecasting intensity, and it's intensity forecast is not "typically considered" by the NHC forecasters.

[andyhb]

In fact, the NHC had no skill at predicting tropical cyclone intensity at days 2, 3, 4, and 5 in 2012.

 

This reads entirely different, but ok.

 

I don't see anywhere in that report that indicated they had "no" skill in forecasting TC intensity in the Atlantic basin in 2012. The OFCL mean forecasting errors were actually below the 5 yr average.

[gulfcane]

This reads entirely different, but ok.

 

I don't see anywhere in that report that indicated that they had "no" skill in forecasting TC intensity in the Atlantic basin in 2012. The OFCL mean forecasting errors were actually below the 5 yr average.

Look at the chart on page 63 to see the NHC had no skill at days 2, 3, 4, and 5.

And from the report: "The intensity models were not very skillful in 2012. The best performers were the consensus aids ICON/IVCN and FSSE, but even thesemodels only had marginal skill through the forecast period. The LGEM, typically one of the better individual models, lacked skill in 2012 and was one of the poorer performing models. HWFI was the worst model at the longer leads, and had skill near -60% at 120 h. The top-performing global models, GFSI and EMXI, were included in the intensity verification for completeness, although they are typically not considered by forecasters. EMXI was not skillful at any time, but still performed better than HWFI at 96 and 120 h. GFSI had some skill early and was better than much of the standard guidance from 12 to

36 h. Beyond that, however, the skill of GFSI decreased and was similar to GHMI.

...."errors were well below their 5-yr means at all forecast times, however, indicating the season’s storms were significantly easier than normal to forecast. Figure 7 shows that there has been a decrease in the intensity errors over the past few years; however, these recent improvements are likely due to a lack of rapidly intensifying hurricanes, which are typically the source of the large forecast errors. Over the long term there has been virtually no net change in error at the shorter leads"

[andyhb]

Look at the chart on page 63 to see the NHC had no skill at days 2, 3, 4, and 5.

...."errors were well below their 5-yr means at all forecast times, however, indicating the season’s storms were significantly easier than normal to forecast. Figure 7 shows that there has been a decrease in the intensity errors over the past few years; however, these recent improvements are likely due to a lack of rapidly intensifying hurricanes, which are typically the source of the large forecast errors. Over the long term there has been virtually no net change in error at the shorter leads"

 

I'm not even arguing the models at this point, I'm talking about the OFCL forecast errors, nowhere there do I see that the NHC had "no" skill in intensity forecasting. The factors that lead to the improvements are irrelevant in my argument. You made an absolute statement that I and others disagreed with, and I have still yet to see anything to definitively back it up.

 

You will notice in the chart that you referenced, there has been a decrease in intensity forecasting error from the NHC since 2007, nothing there indicates (again) that they have "no" skill in forecasting intensity.

[Superstorm93]

Trades in the Caribbean are finally calming down...

 

SST's have warmed considerably

 

 

[Ed Lizard]

High res 12Z FIM9 is LA/MS, verbatim a high end TS.  Not-verbatim, 'looks' like it could be a 'cane.

 

Euro now the outlier ( I say outlier, I don't know where to go anymore for UK Met graphics beyond 72 hours) in not predicting anything beyond a weak low, very deep in the BoC, using the glass half full thing, unless some of the Euro ensembles show stronger and farther North solutions, can't see irrational exuberance being justified quite yet.  The swing towards LA/MS, single biggest 6 hour swing I can remember for the FIM9, or something did get ingested at 12Z  

 

NASA GEOS-5, 6Z 120 hour onboard, HFIP 6Z GFS Ensemble Ensemble Kalman Filter TS wind probs.  GEOS 5 is advertised as a high res climate model, and the portal page has a warning about using its forecasts.

 

5 day TC probs, be interesting how NHC could lemonize something that isn't even a blob yet...

[andyhb]

( I say outlier, I don't know where to go anymore for UK Met graphics beyond 72 hours)

 

"Classic" option goes to 144.

 

http://meteocentre.com/models/models.php?lang=en&mod=ukmet

[phil882]

Just to add my two cents into the general discussion the last few days, it is quite clear global models have gotten substantially better at forecasting TCG and forecasting general intensity of TCs (The ECMWF is still far away the best model in this regard). Adam is completely correct that the ECMWF normally picks up on every substantial system in the MDR. Both Chantal and Dorian were very marginal small TCs.

 

Its worth noting that GFS does still invoke some sort of vortex relocation of bogusing when its known that a TC exists.

 

This can be good and bad. Its good, because otherwise the model grid resolution would often not be able to detect the vortex of small TCs like Chantal and Dorian. As was noted several times during Chantal and Dorian, the ECMWF oftentimes did a poor job with identifying the initial vortex of these TCs, and this is with a substantially smaller grid spacing (~12km). However, its bad because it can often overestimate the size and even intensity of the overall vortex of sheared or shallow low-level vortexes. As was noted in several posts during Dorian's life, the GFS seemed to be depicting a substantially larger and more vertically developed TC than in reality, which allowed Dorian to be more resilient to the hostile and dry environment it moved into as it approached the Lesser Antilles. 

 

Most of the time when you have a large robust system, there isn't a need for vortex relocation or bogusing because its correctly represented in the DA. However, with these smaller systems, that why you often see the GFS be more aggressive than the ECMWF even in marginal conditions thanks due to the synthetically created stronger vortex representation. 

[Superstorm93]

Here's an example from the NHC 5-day TWO PDF regarding TC GEN cases beyond 48 hours...

 

Experimental TWO from last year. I don't know which system...

 

 

 

ALTHOUGH THE NORTH WESTERN CARIBBEAN SEA IS CURRENTLY QUIET…AN AREA OF LOW PRESSURE IS EXPECTED TO FORM IN THAT AREA IN 3 TO 5 DAYS. ENVIRONMENTAL

CONDITONS APPEAR CONDUCIVE FOR DEVELOPMENT DURING THAT TIME AS THE LOW MOVES SLOWLY NORTHWARD. THERE IS A LOW CHANCE…NEAR 0 PERCENT…OF THIS

SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. HOWEVER…THERE IS A HIGH CHANCE…NEAR 60 PERCENT…OF THIS DISTURBANCE BECOMING A

TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

 

 

 

[gulfcane]

I'm not even arguing the models at this point, I'm talking about the OFCL forecast errors, nowhere there do I see that the NHC had "no" skill in intensity forecasting. The factors that lead to the improvements are irrelevant in my argument. You made an absolute statement that I and others disagreed with, and I have still yet to see anything to definitively back it up.

 

You will notice in the chart that you referenced, there has been a decrease in intensity forecasting error from the NHC since 2007, nothing there indicates (again) that they have "no" skill in forecasting intensity.

 

"0" means no skill. Anything below "0" means negative skill. All I can do is show you the facts, I can't make you believe them. I'm not sure what your seeing "since 2007" that is causing you to have beliefs that are simply not true. I would love to know. As for the comments made by phil882 about ECMWF being "far and away the best model" at forecasting general intensity of TC's, this is simply not true. According to the NHC on page 15, the ECMWF "was not skillful at anytime" at predicting tropical cyclone intensity in 2012.

 

[bluewave]

"0" means no skill. Anything below "0" means negative skill. All I can do is show you the facts, I can't make you believe them. I'm not sure what your seeing "since 2007" that is causing you to have beliefs that are simply not true. I would love to know. As for the comments made by phil882 about ECMWF being "far and away the best model" at forecasting general intensity of TC's, this is simply not true. According to the NHC on page 15, the ECMWF "was not skillful at anytime" at predicting tropical cyclone intensity in 2012.

 

 

The ECMWF report begs to differ with that assessment.

 

http://www.ecmwf.int/publications/newsletters/pdf/133.pdf

 

 

Figure 1 shows all available ECMWF HRES forecasts verifying at landfall time. Evidently a major cyclone was predicted to be close to the US east coast in every forecast onwards from about 00 UTC on the 23rd (7 days before landfall, labelled ‘D­7’ on Figure 1). As the event approached these forecasts generally became more and more accurate, with fore­ cast intensity also verifying well – note that in many the central pressure is below 950 hPa (thick red contour), compared with 946 hPa observed at landfall.

 

The ECMWF also beat the official intensity forecast with Dorian correctly showing the weakening trend

north of Puerto Rico. The Euro also was correct in showing Chantal weakening.

 

http://www.nhc.noaa.gov/archive/2013/graphics/al04/loop_5W.shtml

 

http://www.nhc.noaa.gov/archive/2013/graphics/al03/loop_5W.shtml

[andyhb]

"0" means no skill. Anything below "0" means negative skill. All I can do is show you the facts, I can't make you believe them. I'm not sure what your seeing "since 2007" that is causing you to have beliefs that are simply not true. I would love to know. As for the comments made by phil882 about ECMWF being "far and away the best model" at forecasting general intensity of TC's, this is simply not true. According to the NHC on page 15, the ECMWF "was not skillful at anytime" at predicting tropical cyclone intensity in 2012.

 

I'm looking at the chart above it. I'm not using the word "skill" in the context of that graph.

 

Also, pretty sure skill relative to decay is not the same as what you appear to be implying.

[andyhb]

The ECMWF report begs to differ with that assessment.

 

http://www.ecmwf.int/publications/newsletters/pdf/133.pdf

 

 

Figure 1 shows all available ECMWF HRES forecasts verifying at landfall time. Evidently a major cyclone was predicted to be close to the US east coast in every forecast onwards from about 00 UTC on the 23rd (7 days before landfall, labelled ‘D­7’ on Figure 1). As the event approached these forecasts generally became more and more accurate, with fore­ cast intensity also verifying well – note that in many the central pressure is below 950 hPa (thick red contour), compared with 946 hPa observed at landfall.

 

The ECMWF also beat the official intensity forecast with Dorian correctly showing the weakening trend

north of Puerto Rico. The Euro also was correct in showing Chantal weakening.

 

http://www.nhc.noaa.gov/archive/2013/graphics/al04/loop_5W.shtml

 

http://www.nhc.noaa.gov/archive/2013/graphics/al03/loop_5W.shtml

 

I also believe the Euro was the most persistent with Isaac taking a more westward track into the Gulf.

[gulfcane]

The ECMWF report begs to differ with that assessment.

 

http://www.ecmwf.int/publications/newsletters/pdf/133.pdf

 

 

Figure 1 shows all available ECMWF HRES forecasts verifying at landfall time. Evidently a major cyclone was predicted to be close to the US east coast in every forecast onwards from about 00 UTC on the 23rd (7 days before landfall, labelled ‘D­7’ on Figure 1). As the event approached these forecasts generally became more and more accurate, with fore­ cast intensity also verifying well – note that in many the central pressure is below 950 hPa (thick red contour), compared with 946 hPa observed at landfall.

 

The ECMWF also beat the official intensity forecast with Dorian correctly showing the weakening trend

north of Puerto Rico. The Euro also was correct in showing Chantal weakening.

 

More facts, this is the 2012 intensity forecast skill by model. The EMXI is the ECMWF. It's the light blue color and it was the worst performing model for hours 24, 48, and 72. It did beat HWRF intensity at 96 and 120 hours, although it showed nearly -40% skill at 96 hours and -25% at 120 hours. Note the GFS (GFSI) had negative intensity skill after 36 hours.  

 

[Ed Lizard]

I'd like to know what climo actually is for tropical depression strengthening rate in the Gulf in mid-August.

 

And I supported why I think, if GFS track is correct, based on limited area of favorable low-mid level moisture, on not overly aggressive strengthening rate.

 

Still an interplay between track and strength, judging from UK Met (thanks Andy, bookmarked) and Euro versus US and Canadian model.  Weaker systems farther South, farther South weaker systems because of land interaction.  Until it becomes clear where the system is actually developing, track and intensity forecasts are a rather wide range.  Not quite 'Brownsville to Maine', as I recall someone once saying.  But a range. 

[phil882]

"0" means no skill. Anything below "0" means negative skill. All I can do is show you the facts, I can't make you believe them. I'm not sure what your seeing "since 2007" that is causing you to have beliefs that are simply not true. I would love to know. As for the comments made by phil882 about ECMWF being "far and away the best model" at forecasting general intensity of TC's, this is simply not true. According to the NHC on page 15, the ECMWF "was not skillful at anytime" at predicting tropical cyclone intensity in 2012.

 

I was careful with my words for a reason... I said the ECMWF was far and away the best model for forecasting the general intensity. Not the best verbatim forecast, but the best guide for forecasting the intensity of a TC.

 

The problem is when you compare a model directly with SHIFOR, you are only comparing the maximum sustained winds (MSWs) of a global model vs. a statistical model of previous TCs in that same region. Its a grave mistake to take model forecasted MSWs because in most cases global models don't have the resolution to resolve the maximum sustained winds of a TC. The GFS even with a good initialization of a major hurricane will never have the resolution to resolve 100+ knot winds at 10 meters because the grid spacing won't resolve the small inner core that contains those winds. The ECMWF has the highest spectral resolution of all the global models, so it can occasionally resolve strong inner cores of larger TCs, but it doesn't always do this on a consistent basis. Thus, the ECMWF does have the capability in larger storms to forecast a 10 meter wind speed intensity of a major hurricane. It tried to do this with Leslie last year, which was a colossal failure due to its inability to depict proper SST cooling underneath the nearly stationary TC (global models don't yet have coupled SST physics, so they won't do a good job at predicting upwelling weakening of TCs). The GFS also forecasting Leslie to be a very powerful TC, but its wind intensity forecast was lower because its resolution was not able to show 100+ knot winds.

 

So lets logically think this through. 2012 was a year where there were very many weak TCs, but very few major hurricanes. Thus a model like the GFS should could have higher skill in theory because it can never predict the proper intensity of major hurricanes but does reasonably well with 35-50 knot intensities, while a model like the ECMWF might be unfairly scored just because it has the capability to resolve higher wind intensity forecasts. 

[CoastalWx]

Two great posts from Phil. Thanks for clearing it up. Also for those who don't know the forecast skill as far as I'm aware of, is computed by comparing forecast error to the error from a Climatology persistence model (CLIPER)

[phil882]

Just to reiterate gulfcane I'm not disagreeing with the NHC literature you are citing here... its true that the ECMWF preformed poorly if you look just at MSWs of a model grid vs. SHIFOR. However, I think that's not necessarily an enlightening way to document TC intensity error, when dynamical models don't have the same resolution, you are not getting an apples to apples comparison of how well model guidance intensity is preforming. 

[wxtrackercody]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SUN AUG 11 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

OTHER SYSTEMS WITH FORMATION POTENTIAL BEYOND 48 HOURS...

AN AREA OF LOW PRESSURE IS EXPECTED TO FORM ACROSS THE NORTHWESTERN
CARIBBEAN SEA OR THE SOUTHERN GULF OF MEXICO BY THURSDAY OR
FRIDAY...AND ENVIRONMENTAL CONDITIONS ARE FORECAST TO BECOME
SOMEWHAT CONDUCIVE FOR DEVELOPMENT DURING THAT TIME. THIS SYSTEM
HAS A LOW CHANCE...NEAR 0 PERCENT...OF BECOMING A TROPICAL CYCLONE
DURING THE NEXT 48 HOURS...AND A LOW CHANCE...20 PERCENT...OF
BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS.

&&