atlantic Major Hurricane Gonzalo

[Somerset Squall]

The disturbance east of the Leeward Islands has become Tropical Storm Gonzalo, with winds of 35kts. Gonzalo is a small tropical storm, with a modest area of convection over the LLCC, but good banding features. Gonzalo is expected to strengthen as shear is low and waters warm at around 29C. Gonzalo is expected to become a hurricane prior to moving over Puerto Rico. Gonzalo is then expected to turn north around the western side of the subtropical ridge and move into open waters. By day 5, NHC have Gonzalo just shy of major hurricane strength. If Gonzalo doesn't suffer too much from dry air, rapidly strengthening is possible due to Gonzalo's small size.

Edited October 12, 2014 by Somerset Squall

[summer blizzard]

Not bad..

 

[summer blizzard]

Developing eye.

 

65mph, 992mb forecast to reach 110mph.

[summer blizzard]

We have him.... Hurricane Gonzalo.  984mb forecast to reach 115mph...  Now looks a direct hit for Bermuda or near enough!

 

000
WTNT43 KNHC 132056
TCDAT3

HURRICANE GONZALO DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082014
500 PM AST MON OCT 13 2014

Another Air Force Reserve reconnaissance aircraft investigating
Gonzalo this afternoon recently found 700-mb maximum flight-level
winds of 77 kt along with believable SFMR surface winds of 62-67 kt
in the northeastern quadrant, plus a central pressure of 984 mb.
Based on these data, the intensity has been increased to 65 kt,
making Gonzalo the sixth hurricane of the 2014 Atlantic hurricane
season. Note that some higher SFMR winds were observed, but these
were believed to be contaminated by shallow-water shoaling.

The initial motion estimate is 305/10 kt. The center of Gonzalo has
been developing northward on the Guadeloupe radar while the entire
circulation has been moving west-northwestward. The result is now
a northwestward motion, which is expected to continue for the next
36 hours or so. After that time, Gonzalo is forecast to gradually
turn northward as a break in the subtropical to its north develops
by 48-72 hours. On days 4 and 5, the hurricane is forecast to
accelerate to the northeast as the southwesterly flow ahead of
fast-moving deep-layer trough and associated cold front that is
currently located over the south-central United States. The models
are in better agreement on this track scenario with only a minor
eastward shift noted through 36 hours. After that, however, the
models have made a significant westward shift and now bring Gonzalo
very close to Bermuda in the 96-120 hour time period. The official
forecast track lies close to a blend of the GFEX and TVCN consensus
models through 48 hours, and is a little to the right of the
consensus models at 72-120 hours.

Both the radar and satellite presentations of Gonzalo continue to
improve, with a 20 n mi diameter eye noted in the radar data since
about 1400-1500 UTC. Gonzalo has been strengthening at a rate of
20-25 kt since this time yesterday. Given that current environmental
and oceanic conditions are expected to remain essentially unchanged
for the next 48 hours, a similar rate of strengthening is forecast
during that time, with Gonzalo forecast to become a major hurricane
by 48 hours. After that, gradually increasing southwesterly vertical
wind shear ahead of the aforementioned deep-layer trough is expected
to induce gradual weakening. The NHC intensity forecast remains
above the intensity consensus models, and closely follows the SHIPS
intensity model.

Although hurricane conditions are not currently expected in the U.S.
Virgin Islands, only a slight deviation to the left of the forecast
track, or a more rapid strengthening of the storm, would result in
the need to extend the hurricane warning into those areas. Interests
in the hurricane watch area are reminded that the watch means that
hurricane conditions are possible, and in this case within the
next 12-18 hours.

FORECAST POSITIONS AND MAX WINDS

INIT 13/2100Z 17.9N 62.9W 65 KT 75 MPH
12H 14/0600Z 18.8N 64.1W 70 KT 80 MPH
24H 14/1800Z 20.5N 65.7W 80 KT 90 MPH
36H 15/0600Z 22.2N 67.1W 90 KT 105 MPH
48H 15/1800Z 23.8N 68.2W 100 KT 115 MPH
72H 16/1800Z 26.3N 68.5W 100 KT 115 MPH
96H 17/1800Z 30.0N 66.4W 95 KT 110 MPH
120H 18/1800Z 35.0N 62.8W 90 KT 105 MPH

[summer blizzard]

Updated reports suggest 981mb, 73KT.

[summer blizzard]

Look at the convection around the eyewall, dark tends to indicate rapid deepening.

 

[Somerset Squall]

7 named storms, now 6 of them Hurricanes, quite an impressive ratio there. Forecast to become the season's second major too. Although a fairly quiet season so far, it is already much better than last year! I'd love to see Gonzalo make cat 4 status, it has been such a long time since we have seen one in the Atlantic! (Ophelia in 2011 was the last one). It's current peak is only expected to be 100kts (cat 3) however.

 

The Leeward Islands have been soaked by very heavy rains and have seen very strong winds over the last 24hrs. Puerto Rico is in the firing line next although Gonzalo's centre should pass to the north. Then, Gonzalo should swing north out of the eastern Caribbean and towards Bermuda. Bermuda must be feeling a bit unlucky at the moment after just being hit by Fay.

 

 

 

 

 

 

 

 

[Vorticity0123]

7 named storms, now 6 of them Hurricanes, quite an impressive ratio there. Forecast to become the season's second major too. Although a fairly quiet season so far, it is already much better than last year! I'd love to see Gonzalo make cat 4 status, it has been such a long time since we have seen one in the Atlantic! (Ophelia in 2011 was the last one). It's current peak is only expected to be 100kts (cat 3) however..

 

Indeed, Gonzalo is the first well-developed hurricane in a long time in the Western Atlantic , and it is getting very close to becoming the first major hurricane as well! A Hurricane Hunter aircraft found surface winds up to about 90 knots, yielding an upgrade to a category 2 hurricane by the NHC. Furthermore, the eyewall of Gonzalo is also becoming increasingly better defined, though it is not completely closed yet. This can be seen below:

 

CIMSS MIMIC loop of Gonzalo.

 

However, latest satellite imagery shows that Gonzalo is becoming impacted by southwesterly shear. This can be seen by the linear Cirrus clouds emanating away from the core to its southwest (as of 07:15 UTC). 

 

Visible satellite image of Gonzalo.

 

Shear analysis of US Navy also supports this finding, as it shows an upper low NNW-SSE orientated from the north of Haiti all the way to Central America (which can be seen by the southward-dipping of the upper level streamlines (arrows)).

 

Shear analysis from NRL NAVY.

 

It will be interesting to see whether this shear will put an halt to the intensification. It seems to be mainly depending on the future of the upper low. 

 

EDIT: The NHC also mentioned this shear in their discussion, but they expect it to decrease in the short term. Therefore, it looks like this may just be a temporary halt in the intensification process.

 

From the NHC discussion:

 

 

 

The SHIPS model

and a UW-CIMSS shear analysis show about 15 to 20 kt of south-

southwesterly shear over Gonzalo, which may be why the eye has not

become apparent in infrared imagery. The shear is forecast to

decrease and remain low during the next few days while the hurricane

moves over warm water. This should allow for additional

strengthening during the next 12 to 24 hours.

 

Sources:

http://tropic.ssec.wisc.edu/real-time/mimic-tc/2014_08L/webManager/basicGifDisplay.html

http://www.ssd.noaa.gov/PS/TROP/floaters/08L/08L_floater.html

http://www.nrlmry.navy.mil/tc-bin/tc_home2.cgi?AGE=Latest&ACTIVES=14-CPAC-02C.ANA,14-ATL-07L.FAY,14-ATL-08L.GONZALO,14-WPAC-19W.VONGFONG,14-ATL-91L.INVEST,14-WPAC-93W.INVEST&PHOT=yes&ATCF_BASIN=al&SIZE=full&NAV=tc&ATCF_YR=2014&ATCF_FILE=/al082014.14101318.gif&CURRENT_ATCF_FILE=/al082014.14101318.gif&CURRENT=20141014.0000.goes-13.shear.wind.cimss.x.jpg&CURRENT_ATCF=al082014.14101318.gif&ATCF_NAME=al082014&MO=OCT&BASIN=ATL&STYLE=tables&YEAR=2014&YR=14&STORM_NAME=08L.GONZALO&ARCHIVE=active&AREA=pacific/southern_hemisphere&AID_DIR=/SATPRODUCTS/TC/tc14/ATL/08L.GONZALO/shear&DIR=/SATPRODUCTS/TC/tc14/ATL/08L.GONZALO/shear&TYPE=ssmi&PROD=shear&SUB_PROD=scat_over_85h_amb

Edited October 14, 2014 by Vorticity0123

[summer blizzard]

First category 2 since Sandy south of 20N (i.e. a properly deep tropics hurricane).

 

974mb, 110mph, forecast to reach 130mph.

[Wivenswold]

135mph according to the latest NHC forecast. Easing a little before it slams into Bermuda.

[Somerset Squall]

I'd be surprised if Gonzalo wasn't declared the season's second major next advisory, the eye appears to be clearing:

Winds currently at 95kts (cat 2) and expected to peak at 115kts (cat 4) over the next couple of days. As I said earlier, this would be the first cat 4 since Ophelia in 2011 if it were to occur.

[gottolovethisweather]

At last! some action in the Atlantic and it may just blow out of the water my previous "gut feeling" of October being a largely quiet, relatively undisturbed picture for most of England. Granted, we are but halfway through and I'm not sure where Gonzalo is expected to track either? Is there like to be any other TS developments in the mix before October is out? As for the UK, during the rest of October I would favour a NW/SE split with any ex-Hurricanes likely to effect Greenland and Iceland and extreme NW parts of the UK if anything, but you never know.

Edited October 14, 2014 by gottolovethisweather

[Vorticity0123]

At last! some action in the Atlantic and it may just blow out of the water my previous "gut feeling" of October being a largely quiet, relatively undisturbed picture for most of England. Granted, we are but halfway through and I'm not sure where Gonzalo is expected to track either? Is there like to be any other TS developments in the mix before October is out? As for the UK, during the rest of October I would favour a NW/SE split with any ex-Hurricanes likely to effect Greenland and Iceland and extreme NW parts of the UK if anything, but you never know.

 

To answer your question about Gonzalo, in short, both the ECMWF and GFS expect it to be taken up into the dominant trough to the west of the UK, in which it is being swung eastward over the UK via the Benelux toward Denmark as a weak open surface trough.

 

5 Day forecast from NHC

 

The long answer implies that, initially, Gonzalo is forecast to recurve in the direction of Bermuda/Newfoundland and possibly even making a direct hit there. This can be seen in  the latest NHC forecast of the system:

 

NHC track forecast of Gonzalo

 

Note that even when Gonzalo reaches Newfoundland (which lies at almost 50N), it is still forecast to produce hurricane force winds. This means that both Bermuda and Newfoundland should really be on their guard for this system.

 

Timing differences

 

Afterward, there are some timing differences between the ECMWF and the GFS, with the latter model bringing Gonzalo much earlier at Newfoundland than the ECMWF. Below are both model forecasts for comparison:

 

500 hPa heights + surface level pressure (contours) from the GFS, 12Z run, T+120.

 

500 hPa heights + surface level pressure (contours) from the ECMWF, 12Z run, T+120.

 

In the GFS forecast (upper one), Gonzalo can be seen to the right of Newfoundland (extreme left part of the map, sub-980 mb low with a very sharp pressure gradient). However, in the ECMWF forecast, Gonzalo can be seen just entering the map west-southwest of Newfoundland, with the center barely visible on the image. This is a huge timing difference for just 5 days out. It seems to be depending on the strength of the trough over Canada, which is much stronger on the GFS than on the ECMWF (indicated by the blue colours on the GFS map as opposed to the green colours on the ECMWF map).

 

Far-future forecast

 

From now on, the GFS scenario will be shown in the forecast. Note that the ECMWF shows quite a similar pattern. 

 

Below is the forecast for 6 days out, 24 hours after the images above:

 

500 hPa heights + surface level pressure (contours) from the GFS, 12Z run, T+144.

 

Gonzalo is the low to the south of Iceland, directly to the west of Schotland. Note that Gonzalo still is a separate system, but it is being steered by the low over and to the east of Iceland. It can be seen that Gonzalo has weakened pretty much, and its central pressure is just low enough to maintain a separate identitiy.

 

24 hours later, the system is already in the North sea, as can be seen in the following model output from the GFS:

 

500 hPa heights + surface level pressure (contours) from the GFS, 12Z run, T+168.

 

All that is left of Gonzalo is the dipping in pressure (isobars) over and to the north of the Benelux. In fact, Gonzalo has almost completely been taken up by the low pressure area extending from Newfoundland all the way to Moscow.

 

It is important to stress that this is just a single forecast for 7 days out, and therefore it is very likely to change in the near future. This is also evident by the timing differences which are already visible at a timeframe of just 5 days out.

 

I hope this answers your question satisfactory. Sorry to be a bit off-topic!

 

Sources:

http://www.nhc.noaa.gov/refresh/graphics_at3+shtml/145507.shtml?5-daynl?large#contents

http://www.wetterzentrale.de/topkarten/fsavneur.html

Edited October 14, 2014 by Vorticity0123

[gottolovethisweather]

To answer your question about Gonzalo, in short, both the ECMWF and GFS expect it to be taken up into the dominant trough to the west of the UK, in which it is being swung eastward over the UK via the Benelux toward Denmark as a weak open surface trough.

 

5 Day forecast from NHC

 

The long answer implies that, initially, Gonzalo is forecast to recurve in the direction of Bermuda/Newfoundland and possibly even making a direct hit there. This can be seen in  the latest NHC forecast of the system:

 

 

NHC track forecast of Gonzalo

 

Note that even when Gonzalo reaches Newfoundland (which lies at almost 50N), it is still forecast to produce hurricane force winds. This means that both Bermuda and Newfoundland should really be on their guard for this system.

 

Timing differences

 

Afterward, there are some timing differences between the ECMWF and the GFS, with the latter model bringing Gonzalo much earlier at Newfoundland than the ECMWF. Below are both model forecasts for comparison:

 

 

500 hPa heights + surface level pressure (contours) from the GFS, 12Z run, T+120.

 

 

500 hPa heights + surface level pressure (contours) from the ECMWF, 12Z run, T+120.

 

In the GFS forecast (upper one), Gonzalo can be seen to the right of Newfoundland (extreme left part of the map, sub-980 mb low with a very sharp pressure gradient). However, in the ECMWF forecast, Gonzalo can be seen just entering the map west-southwest of Newfoundland, with the center barely visible on the image. This is a huge timing difference for just 5 days out. It seems to be depending on the strength of the trough over Canada, which is much stronger on the GFS than on the ECMWF (indicated by the blue colours on the GFS map as opposed to the green colours on the ECMWF map).

 

Far-future forecast

 

From now on, the GFS scenario will be shown in the forecast. Note that the ECMWF shows quite a similar pattern. 

 

Below is the forecast for 6 days out, 24 hours after the images above:

 

 

500 hPa heights + surface level pressure (contours) from the GFS, 12Z run, T+144.

 

Gonzalo is the low to the south of Iceland, directly to the west of Schotland. Note that Gonzalo still is a separate system, but it is being steered by the low over and to the east of Iceland. It can be seen that Gonzalo has weakened pretty much, and its central pressure is just low enough to maintain a separate identitiy.

 

24 hours later, the system is already in the North sea, as can be seen in the following model output from the GFS:

 

 

500 hPa heights + surface level pressure (contours) from the GFS, 12Z run, T+168.

 

All that is left of Gonzalo is the dipping in pressure (isobars) over and to the north of the Benelux. In fact, Gonzalo has almost completely been taken up by the low pressure area extending from Newfoundland all the way to Moscow.

 

It is important to stress that this is just a single forecast for 7 days out, and therefore it is very likely to change in the near future. This is also evident by the timing differences which are already visible at a timeframe of just 5 days out.

 

I hope this answers your question satisfactory. Sorry to be a bit off-topic!

 

Sources:

http://www.nhc.noaa.gov/refresh/graphics_at3+shtml/145507.shtml?5-daynl?large#contents

http://www.wetterzentrale.de/topkarten/fsavneur.html

 

Excellent analysis, very helpful. Seems like my post just now is on the right track too. A tricky forecast for the experts assessing the long-termer outlook for the UK and your patch, especially once these beasts get caught up in the Atlantic flow. Could get quite interesting soon though for us Hurricane followers and perhaps the ramifications of which will also effect us in the UK and further parts of Europe too.

Edited October 14, 2014 by gottolovethisweather

[Somerset Squall]

Gonzalo has become the season's second major hurricane, with winds of 100kts, making it a cat 3 on the SS scale. Further strengthening is anticipated in the low shear and warm sea temperature environment. NHC are expecting a peak of 120kts. Interesting to note that Gonzalo's pressure of 970mb is a little high for a 100kt hurricane. Edouard, which also had 100kt winds, had a lowest pressure of 955mb.

[knocker]

wrong thread.

Edited October 14, 2014 by knocker

[summer blizzard]

Holy intensification Batman ! This was the weak storm that went by SNE on Sat, now at 958mb over the Nrn Atlantic!

 

https://twitter.com/Ants_SNEweather

 

Your thinking of Fay.

 

This one is yet to cripple Bermuda.

[knocker]

Your thinking of Fay.

 

This one is yet to cripple Bermuda.

 

Whoops. Stupid. Cheers sb.

[summer blizzard]

Recon have found 959mb. 125KT flight winds, no idea what that is at the surface.

[summer blizzard]

125mph, 954mb.

 

Possible eyewall replacement cycle means we might be around 130mph for some time but conditions won't peak for another 18-24 hours so all depends whether it holds off, gets done quickly or causes stabalisation.

[Polar Bear]

Latest public advisory at 8.00am AST http://www.nhc.noaa.gov/text/refresh/MIATCPAT3+shtml/151151.shtml?

 

Strong Cat 3  - 125mph max sustained wind - 951mb.........

[summer blizzard]

Now category 4.

[matty40s]

I am pretty sure we will be impacted by Gonzalo, late Monday to Tuesday.

Track variability is obviously difficult to pinpoint at this range, but the latest 5 day from NOAA shows that some if not all of the UK will be affected.

[knocker]

The GFS has it fizzling out just here

 

 

[Somerset Squall]

Winds peaked at 115kts earlier, which is category 4 on the SS scale. The ongoing eyewall replacement cycle has weakened Gonzalo back to cat 3 status, with winds of 110kts. The hurricane looks less organised than earlier, with the convection around the degraded eye being asymmetric. Once the cycle completes however, Gonzalo could recover as shear will remain low for about another 48hrs.