TS Nate

[Srain]

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AL, 15, 2011090718, , BEST, 0, 201N, 929W, 40, 1004, TS,

[janetjanet998]

this cant be good for the texas fires..

This may increase the dry NNE wind speeds if it moves north and stalls

not as bad as with Lee but even 5-8MPH (now) versus 12-15mpH gusts to 20-25 will make a difference

[wxsmwhrms]

12Z GFS EnKF doesn't really look like any of the solutions we have discussed. It is much stronger than the GFS and ends up kind of in between the GFS and the EC. It never gets it N of 22N, and has it going due W into Mexico at that latitude in 5 days (weakening at LF after getting down to 973 mb). FIMY is similar, but its ensembles are very diverse and range from being well inland over the SE US to well inland over Mexico in 5 days. Out of 10 members, 3 go for the northern Gulf coast, 3 go for Mexico, and 3 are kind of stuck out in the Gulf in between (1 just doesn't develop it).

[wxmx]

12Z GFS EnKF doesn't really look like any of the solutions we have discussed. It is much stronger than the GFS and ends up kind of in between the GFS and the EC. It never gets it N of 22N, and has it going due W into Mexico at that latitude in 5 days (weakening at LF after getting down to 973 mb). FIMY is similar, but its ensembles are very diverse and range from being well inland over the SE US to well inland over Mexico in 5 days. Out of 10 members, 3 go for the northern Gulf coast, 3 go for Mexico, and 3 are kind of stuck out in the Gulf in between (1 just doesn't develop it).

Going with a GFS, GFS EnKF, Euro and Ukie consensus, it looks like a LF between Tuxpan and just north of La Pesca...probably as a hurricane in about 5 days (discrete coordinate ~ 23N 97.9W, 70kts... intensity forecasts could get higher depending on the evolution of the storm)

[wxsmwhrms]

Going with a GFS, GFS EnKF, Euro and Ukie consensus, it looks like a LF between Tuxpan and just north of La Pesca...probably as a hurricane in about 5 days (discrete coordinate ~ 23N 97.9W, 70kts... intensity forecasts could get higher depending on the evolution of the storm)

I would not include the GFS in a consensus. I think it is the one model that can pretty much be declared clueless in this forecast cycle. My guess is NHC will not show anything near a landfall at this point in the 5 day period to allow themselves plenty of flexibility.

[wxmx]

I would not include the GFS in a consensus. I think it is the one model that can pretty much be declared clueless in this forecast cycle. My guess is NHC will not show anything near a landfall at this point in the 5 day period to allow themselves plenty of flexibility.

The GFS is actually just S of the range I gave. I agree about the 5 day period...but it will be rather close to land at that timeframe, IMO.

[thewxmann]

Not a met here but I'd give a 60/40 shot of MX/US landfall. GFS is out to lunch; a Euro initial movement coupled with a GFS synoptic evolution would bring this to the Gulf Coast. I don't think the latter has a good handle on initial conditions right now. I'm liking a track like Bret, except a sharper turn further south.

The dry air is a bit daunting but if anything right now the frontal system over the GOM is helping Nate with some baroclinicity to boost convection. The upper level system is also helping with outflow.

[donsutherland1]

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AL, 15, 2011090718, , BEST, 0, 201N, 929W, 40, 1004, TS,

Given ASCAT and an 18z Dvorak score of T1.0, I'm wondering whether the model has initialized 96L too aggressively e.g., pehaps it might have reached TD status, but not TS status. We'll know soon enough when the NHC issues its 5 pm advisories.

[PSUBlizzicane2007]

Given ASCAT and an 18z Dvorak score of T1.0, I'm wondering whether the model has initialized 96L too aggressively e.g., pehaps it might have reached TD status, but not TS status. We'll know soon enough when the NHC issues its 5 pm advisories.

Recon is better than ASCAT and Dvoark.

[HurricaneJosh]

Given ASCAT and an 18z Dvorak score of T1.0, I'm wondering whether the model has initialized 96L too aggressively e.g., pehaps it might have reached TD status, but not TS status. We'll know soon enough when the NHC issues its 5 pm advisories.

If the circulation is closed and they're finding uncontaminated winds of at least 34 kt, wouldn't that make it a TS?

[donsutherland1]

Recon is better than ASCAT and Dvoark.

Was the latest recon posted? I know as of 2 pm, a recon plane was headed there. I refreshed and didn't see a vortex message. Obviously, if recon. found the winds, then the upgrade would be justified.

[dan88]

Was the latest recon posted? I know as of 2 pm, a recon plane was headed there. I refreshed and didn't see a vortex message. Obviously, if recon. found the winds, then the upgrade would be justified.

53kt W winds at flight level, pressure around 1004mb, SFMR up to 44kt

[Zachary Lassiter]

53kt W winds at flight level, pressure around 1004mb, SFMR up to 44kt

how do you read the recon text?

[battlebrick]

how do you read the recon text?

use this awesome site for decoded recon:

http://tropicalatlantic.com/recon/

[dan88]

Speaking of recon, it's doing the second leg center pass now, center (or at least wind shift they found on this pass since it may be elongated) looks to be roughly 20.3N 92.6W

[donsutherland1]

53kt W winds at flight level, pressure around 1004mb, SFMR up to 44kt

Never mind. I was getting an old image. I've restarted the computer and have the up to date data.

[Marion_NC_WX]

EricLawWLBTEric Law by wxbrad@wxbrad I'm told by sources they may not issue advisory for Nate just yet...this was as of about 20 min ago.

[Weathergun]

TROPICAL STORM NATE FORECAST/ADVISORY NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152011 2100 UTC WED SEP 07 2011 CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY... THE GOVERNMENT OF MEXICO HAS ISSUED A TROPICAL STORM WARNING FOR THE COAST OF MEXICO FROM CHILITEPEC TO CELESTUN. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MEXICO FROM CHILITEPEC TO CELESTUN A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN 12 HOURS. TROPICAL STORM CENTER LOCATED NEAR 20.2N 92.4W AT 07/2100Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE EAST-SOUTHEAST OR 110 DEGREES AT 2 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT. 34 KT....... 0NE 90SE 75SW 60NW. 12 FT SEAS.. 0NE 0SE 90SW 0NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 20.2N 92.4W AT 07/2100Z AT 07/1800Z CENTER WAS LOCATED NEAR 20.2N 92.5W FORECAST VALID 08/0600Z 20.0N 92.1W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 30NE 90SE 75SW 60NW. FORECAST VALID 08/1800Z 20.1N 91.9W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 30NE 30SE 30SW 30NW. 34 KT... 60NE 60SE 70SW 70NW. FORECAST VALID 09/0600Z 20.4N 92.1W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 30SE 40SW 40NW. 34 KT... 70NE 70SE 80SW 80NW. FORECAST VALID 09/1800Z 21.0N 92.5W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT...100NE 90SE 90SW 100NW. FORECAST VALID 10/1800Z 22.5N 93.5W MAX WIND 70 KT...GUSTS 85 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT...100NE 90SE 90SW 100NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY OUTLOOK VALID 11/1800Z 23.0N 95.0W MAX WIND 75 KT...GUSTS 90 KT. OUTLOOK VALID 12/1800Z 23.0N 96.5W MAX WIND 75 KT...GUSTS 90 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.2N 92.4W NEXT ADVISORY AT 08/0300Z $ FORECASTER BLAKE/ZELINSKY NNNN

[wxmx]

Just east-southeast of La Pesca.... 75kts, my guess wasnt that bad

[HurricaneJosh]

Interestingly, they have it moving due W toward the coast at Day 5.

[wxsmwhrms]

Just east-southeast of La Pesca.... 75kts, my guess wasnt that bad

Nope, pretty darn close! :-) It is still far enough off shore that they can show a track more to the right if that becomes necessary, but yet also turn it harder left if a solution more like the GFS EnKF comes to pass.

BTW, I was just looking at the EC ensemble means, and it is somewhat deeper with the 500 mb trough coming down and clearly has a number of members right of the operational run. Was wondering if anyone who has access to the actual members could share some insight as to what they show WRT track.

[ColdFront77]

TROPICAL STORM NATE FORECAST/ADVISORY NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152011 2100 UTC WED SEP 07 2011 CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY... THE GOVERNMENT OF MEXICO HAS ISSUED A TROPICAL STORM WARNING FOR THE COAST OF MEXICO FROM CHILITEPEC TO CELESTUN. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * MEXICO FROM CHILITEPEC TO CELESTUN A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN 12 HOURS. TROPICAL STORM CENTER LOCATED NEAR 20.2N 92.4W AT 07/2100Z POSITION ACCURATE WITHIN 30 NM PRESENT MOVEMENT TOWARD THE EAST-SOUTHEAST OR 110 DEGREES AT 2 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT. 34 KT....... 0NE 90SE 75SW 60NW. 12 FT SEAS.. 0NE 0SE 90SW 0NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 20.2N 92.4W AT 07/2100Z AT 07/1800Z CENTER WAS LOCATED NEAR 20.2N 92.5W FORECAST VALID 08/0600Z 20.0N 92.1W MAX WIND 45 KT...GUSTS 55 KT. 34 KT... 30NE 90SE 75SW 60NW. FORECAST VALID 08/1800Z 20.1N 91.9W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 30NE 30SE 30SW 30NW. 34 KT... 60NE 60SE 70SW 70NW. FORECAST VALID 09/0600Z 20.4N 92.1W MAX WIND 60 KT...GUSTS 75 KT. 50 KT... 30NE 30SE 40SW 40NW. 34 KT... 70NE 70SE 80SW 80NW. FORECAST VALID 09/1800Z 21.0N 92.5W MAX WIND 65 KT...GUSTS 80 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT...100NE 90SE 90SW 100NW. FORECAST VALID 10/1800Z 22.5N 93.5W MAX WIND 70 KT...GUSTS 85 KT. 50 KT... 50NE 40SE 40SW 50NW. 34 KT...100NE 90SE 90SW 100NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY OUTLOOK VALID 11/1800Z 23.0N 95.0W MAX WIND 75 KT...GUSTS 90 KT. OUTLOOK VALID 12/1800Z 23.0N 96.5W MAX WIND 75 KT...GUSTS 90 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.2N 92.4W NEXT ADVISORY AT 08/0300Z $ FORECASTER BLAKE/ZELINSKY NNNN

TROPICAL STORM NATE FORECAST/ADVISORY NUMBER 1

NWS NATIONAL HURRICANE CENTER MIAMI FL AL152011

2100 UTC WED SEP 07 2011

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

THE GOVERNMENT OF MEXICO HAS ISSUED A TROPICAL STORM WARNING FOR THE

COAST OF MEXICO FROM CHILITEPEC TO CELESTUN.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...

* MEXICO FROM CHILITEPEC TO CELESTUN

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE

EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN 12

HOURS.

TROPICAL STORM CENTER LOCATED NEAR 20.2N 92.4W AT 07/2100Z

POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE EAST-SOUTHEAST OR 110 DEGREES AT 2 KT

ESTIMATED MINIMUM CENTRAL

PRESSURE 1004 MB

MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.

34 KT....... 0NE 90SE 75SW 60NW.

12 FT SEAS.. 0NE 0SE 90SW 0NW.

WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL

MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.2N 92.4W AT 07/2100Z

AT 07/1800Z CENTER WAS LOCATED NEAR 20.2N 92.5W

FORECAST VALID 08/0600Z 20.0N 92.1W

MAX WIND 45 KT...GUSTS 55 KT.

34 KT... 30NE 90SE 75SW 60NW.

FORECAST VALID 08/1800Z 20.1N 91.9W

MAX WIND 50 KT...GUSTS 60 KT.

50 KT... 30NE 30SE 30SW 30NW.

34 KT... 60NE 60SE 70SW 70NW.

FORECAST VALID 09/0600Z 20.4N 92.1W

MAX WIND 60 KT...GUSTS 75 KT.

50 KT... 30NE 30SE 40SW 40NW.

34 KT... 70NE 70SE 80SW 80NW.

FORECAST VALID 09/1800Z 21.0N 92.5W

MAX WIND 65 KT...GUSTS 80 KT.

50 KT... 50NE 40SE 40SW 50NW.

34 KT...100NE 90SE 90SW 100NW.

FORECAST VALID 10/1800Z 22.5N 93.5W

MAX WIND 70 KT...GUSTS 85 KT.

50 KT... 50NE 40SE 40SW 50NW.

34 KT...100NE 90SE 90SW 100NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 175 NM

ON DAY 4 AND 225 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 11/1800Z 23.0N 95.0W

MAX WIND 75 KT...GUSTS 90 KT.

OUTLOOK VALID 12/1800Z 23.0N 96.5W

MAX WIND 75 KT...GUSTS 90 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.2N 92.4W

NEXT ADVISORY AT 08/0300Z

$$

FORECASTER BLAKE/ZELINSKY

[CoastalWx]

Looking at infrared, would never have thought TS. Right to TS again with Nate.

[wxmx]

18z GFS is a hair further south... ok, ok we got it, now stop it.

[donsutherland1]

Now that Nate has formed, I have looked at the set of storms that developed in the general region (18.2N-22.2N/89.9W-94.4W) on September 7 +/- 20 days since 1950. The result has overwhelmingly favored landfall in Mexico. The statistics are as follows:

Landfall:

Mexico: 78%

U.S.: 22%: Earl (1998) on the Florida Panhandle and Bret (1999) in Texas.

If one takes a look at the upper air patterns, one finds that in the cases of Earl and Bret, there was a deepening and expanding trof in the eastern U.S. In this case, according to the GFS ensembles, there will be a de-amplifying and shrinking trough in the eastern U.S. Therefore, with this data and a look at the upper air patterns, I believe odds strongly favor landfall in Mexico. Initially, I had thought odds had somewhat favored Gulf Coast landfall, but that was before Nate formed and before I had a chance to review the historic upper air patterns.

In terms of intensity, Nate will probably grow into a Category 1 hurricane. There is some prospect that Nate could reach Category 2 strength. However, that is probably a low probability, as the storms that made landfall in Mexico were all tropical storms or Category 1 hurricanes. Earl (Category 2) and Bret (Category 4) were the only storms that grew stronger than Category 1. In the overall sample, one-third of the storms were tropical storms and two-thirds peaked at hurricane strength. Also, two-thirds of the hurricanes peaked at Category 1 strength.

[Amped]

There is a lot of shear near the northern gulf coast if this were to go there. I still can't believe how much dry air there is too the west, but I guess it was the dry moist boundry that spun up the thing in the first place.

[wxsmwhrms]

Now that Nate has formed, I have looked at the set of storms that developed in the general region (18.2N-22.2N/89.9W-94.4W) on September 7 +/- 20 days since 1950. The result has overwhelmingly favored landfall in Mexico. The statistics are as follows:

Landfall:

Mexico: 78%

U.S.: 22%: Earl (1998) on the Florida Panhandle and Bret (1999) in Texas.

If one takes a look at the upper air patterns, one finds that in the cases of Earl and Bret, there was a deepening and expanding trof in the eastern U.S. In this case, according to the GFS ensembles, there will be a de-amplifying and shrinking trough in the eastern U.S. Therefore, with this data and a look at the upper air patterns, I believe odds strongly favor landfall in Mexico. Initially, I had thought odds had somewhat favored Gulf Coast landfall, but that was before Nate formed and before I had a chance to review the historic upper air patterns.

In terms of intensity, Nate will probably grow into a Category 1 hurricane. There is some prospect that Nate could reach Category 2 strength. However, that is probably a low probability, as the storms that made landfall in Mexico were all tropical storms or Category 1 hurricanes. Earl (Category 2) and Bret (Category 4) were the only storms that grew stronger than Category 1. In the overall sample, one-third of the storms were tropical storms and two-thirds peaked at hurricane strength. Also, two-thirds of the hurricanes peaked at Category 1 strength.

Don, thanks for posting this, this is really helpful. I think the deamplifying nature of the trough is a big key, and why the system has the potential to turn back to the west rather than continuing to move NE. Having said that, I think the shorter term evolution is important obviously, If the system does not gain much latitude, it can stay farther S and do that move to the west more like the GFS and its variants show. However, I am still quite concerned that if the system gains as much latitude as the ECMWF and UK show in the shorter term, that a strong system would still get caught up into the trough, even with it deamplifying.

[phil882]

Don, thanks for posting this, this is really helpful. I think the deamplifying nature of the trough is a big key, and why the system has the potential to turn back to the west rather than continuing to move NE. Having said that, I think the shorter term evolution is important obviously, If the system does not gain much latitude, it can stay farther S and do that move to the west more like the GFS and its variants show. However, I am still quite concerned that if the system gains as much latitude as the ECMWF and UK show in the shorter term, that a strong system would still get caught up into the trough, even with it deamplifying.

However, the GFS does pose a reasonable solution that if Nate does not gain much latitude in the next 24-48 hours, it will likely not have a chance to escape further northward before being forced west or west-southwest into Mexico due to the building mid-level ridge. Ultimately, I think that its far more likely that the models still possess a northward bias as they self correct for the continued +SOI that tends to favor more ridging.

[wxsmwhrms]

However, the GFS does pose a reasonable solution that if Nate does not gain much latitude in the next 24-48 hours, it will likely not have a chance to escape further northward before being forced west or west-southwest into Mexico due to the building mid-level ridge. Ultimately, I think that its far more likely that the models still possess a northward bias as they self correct for the continued +SOI that tends to favor more ridging.

Completely agree. If it stays as far S as the GFS and its ilk show in the first 2-3 days, then I would definitely be fully on board on it staying S. Where I have more of an issue is the UK and ECMWF showing it getting as far N as 25-26N, and still managing to miss the trough. When I look at the ECMWF and particularly it ensemble at 72-96 hour with the 500 mb pattern and the location of the system, it really strikes me as a NE movement rather than a movement to Mexico. The climatology also suggests that a track into Mexico would most likely occur on a due W track rather than getting up to like 25N and turning SW.

[wxmx]

HWRF and GFDL are hinting at a major near Tampico or just north