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2019 Atlantic Hurricane Season
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Lorenzo is going to be interesting to watch, except for all the comparisons to Ophelia already!
GFS last two OP runs have it dropping South of us:
If two storms of this nature track over us in as many years, that is no longer anomalous and something is up.
We're in for an interesting couple of weeks, but arguably, an extremely interesting and less predictable climate from this point forward.0 -
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Tropical Storm Lorenzo progressing showing bands rotating within the circulation , NHC saying it has an intensity of 55kts. Not progressing as fast as previously modeled yet still in a favorable environment to intensify into a Hurricane by tomorrow.
NHC
FORECAST POSITIONS AND MAX WINDS
INIT 24/1500Z 12.4N 29.3W 55 KT 65 MPH
12H 25/0000Z 12.9N 31.3W 65 KT 75 MPH
24H 25/1200Z 13.6N 34.0W 75 KT 85 MPH
36H 26/0000Z 14.2N 36.6W 85 KT 100 MPH
48H 26/1200Z 15.0N 38.8W 95 KT 110 MPH
72H 27/1200Z 18.0N 41.9W 100 KT 115 MPH
96H 28/1200Z 21.1N 44.3W 105 KT 120 MPH
120H 29/1200Z 23.9N 45.3W 100 KT 115 MPH
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Windy.com has it tracking west of Ireland. All up in the air, didn’t Ophelia change to an eastern direction after veering west?
Nope. Bear in mind these graphics start and end when NHC advisories did, specifically ending very abruptly as soon as it went extratropical despite having major impacts here.
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The GFS, despite its upgrade, has performed terribly this season. On each storm it has been completely wild of the mark in the early stages of the developing systems. The ECM has been king again, so I would be siding with it more for now, backed up by the fact that most other models are showing similar.
There is still a large area of dry air for Lorenzo to get through as it swings a little more northwestwards now. The SHIPS had been jumping at rapid intensification this time yesterday, but it's backed well back down in today's runs. Despite the vis and IR imagery showing some banding, microwave scans show no real organisation of deep convection nor a central core. We'd be needing to see something better than this develop or it may not reach the Cat 3 promise it has been showing. In 5 days it will be getting out over colder seas around 26 N.
Water vapour
Ocean Heat Content
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A big switch in the GFS Op (AVNO), Ensemble mean (AEMN) and Control run (AC00) between 00Z and 06Z runs. A total swing west now, especially the op, which has the track now west of Ireland instead of over France and Germany. As stated, all still model vomit for now.
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NHC Storm Description:
25 Sep 2019 - 15:00 UTC ...LORENZO CONTINUES TO STRENGTHEN... ...EXPECTED TO BECOME A MAJOR HURRICANE BY THURSDAY... As of 11:00 AM AST Wed Sep 25 the center of Lorenzo was located near 14.1, -35.1 with movement WNW at 17 mph. The minimum central pressure was 983 mb with maximum sustained winds of about 85 mph.
Projected strength increased a bit again.
NHC
FORECAST POSITIONS AND MAX WINDS
INIT 25/1500Z 14.1N 35.1W 75 KT 85 MPH
12H 26/0000Z 14.4N 37.1W 85 KT 100 MPH
24H 26/1200Z 15.3N 39.2W 100 KT 115 MPH
36H 27/0000Z 16.7N 40.8W 110 KT 125 MPH
48H 27/1200Z 18.4N 42.2W 110 KT 125 MPH
72H 28/1200Z 21.9N 44.2W 110 KT 125 MPH
96H 29/1200Z 25.0N 44.5W 105 KT 120 MPH
120H 30/1200Z 29.0N 42.0W 105 KT 120 MPH
$$
Forecaster Beven0 -
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Wind speeds continue to rise, pressure dropping .
https://www.tropicaltidbits.com/storminfo/
Hurricane LORENZO
As of 18:00 UTC Sep 25, 2019:
Location: 14.3°N 36.3°W
Maximum Winds: 80 kt Gusts: 100 kt
Minimum Central Pressure: 978 mb
Environmental Pressure: 1012 mb
Radius of Circulation: 180 NM
Radius of Maximum Wind: 20 NM
64 kt Wind Radii by Quadrant:
https://twitter.com/philklotzbach/status/1176877147580821504?s=20
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Models are struggling.
It veers wildly west in the 18Z GFS as well, but also deepens to 930mb or the equivalent of a Category 4 storm, almost as far north as Iceland while still retaining some tropical features.
That's just not going to happen.
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Models are struggling.
It veers wildly west in the 18Z GFS as well, but also deepens to 930mb or the equivalent of a Category 4 storm, almost as far north as Iceland while still retaining some tropical features.
That's just not going to happen.
It's really only the GFS that's been struggling, varying from Poland to Greenland in the space of 3 runs. The others have been fairly consistent.0 -
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The parallels with 2004 will be interesting to see once this season ends. It got off to a later start thanks to Saharan dust, but the Modoki El Nino phenomenon has had more or less the same result - a back-loaded season in which wind shear plummeted across the basin as the summer progressed.
For comparison:
I'm not entirely sure on the mechanics of how this SST setup in the Pacific enhances the Atlantic hurricane season, but it seems to have two components - one is, fairly straightforwardly, that increased convection West of the date line generates upper-level outflow, which travels Eastward before sinking over the Eastern Pacific and choking tropical disturbances and thunderstorms in that area. Consequently, upper-level outflow from the Eastern Pacific, which would normally suppress the Atlantic to some degree in the same manner, is reduced.
However, the second component is beyond my current level of understanding - the SST setup affects the Walker Circulation in a way which reduces upper-level wind shear over the Atlantic when El Nino conditions are displaced into the Central rather than the Eastern Pacific. This is partly what led to such an extreme hurricane season in 2004 and subsequently the record breaking season in 2005 - this pattern, in combination with the ongoing positive AMO phase, allowed major hurricanes to spin up in July 2005 where normally wind shear and subsidence from Eastern Pacific storms' outflow would choke most tropical waves before they have a chance to build a closed circulation.
If this pattern holds, it wouldn't surprise me to see this season continuing to be extremely active into the Winter, followed by an early burst of activity next summer, similar to 2004 and 2005 respectively. The only factor which is out of sync is the PDO, which is a lot higher now than it was in the 2000s - but as evidenced by 2017, the PDO isn't nearly as influential as ENSO when it comes to Atlantic tropical cyclogenesis.0 -
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Just some observations about the track of what will be left of Lorenzo ( by then probably an Ex Tropical cyclone ) when it moves further N towards us.
ECM has been very consistent in taking the system well off the W coast now for a number of days. The latest run a bit closer but still keeping the strongest winds well off shore. GFS now looking more like the ECM ,GEM resembling the same track also.
The three models mentioned go on to show the remnants of Lorenzo being absorbed into a large area of LP initially taking the system well away from Ireland.
Currently at over 7 days out looks like a powerful storm when it reaches off the SW / W . A lot could change but worth keeping a daily log of what the models are projecting . Would need to keep an eye on rainfall also.
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All >=115kt hurricanes since 1960 on or after 26th September. Unless I've made a howler in analysing the data, #Lorenzo is quite an anomaly.
credit:
https://twitter.com/catinsight0 -
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JanuarySnowstor wrote: »Needs watching as it's only a hares breath from a direct hit. While it remains modelled to our West overall concensus today is to move it closer to our shore than what was previously thought
Do you mean a " hair's breadth"? Maybe your version is more interesting! And sure, what is one more gale here! As she listens to wind and rain battering the dwelling..
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Meanwhile, Typhoon Mitag is spinning up northeast of Manila and looks like brushing by Taiwan, Shanghai and making landfall in South Korea as a Cat 1 next Wednesday. For a while it was looking a little further east and slower, possibly coming closer to Kobe, where Ireland will play Samoa on Thursday.
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The 2019 Atlantic season was extremely quiet up to the last week in August, but then spung to action and generated several named storms, two of which reached Cat 5 status (Dorian and Lorenzo). This timing perfectly matched the climatological peak activity, which is centred around September 10th.
The reasons for the enhanced activity are primarily the ENSO-nuetral conditions, the timing of Madden Julian Oscillation (Phase 1 occuring right at that time) and the warm phase of the Atlantic Multidecadal Oscillation (a natural warming of waters in the North Atlantic, which is known to enhance tropical activity).
Lorenzo had the best possible conditons to rapidly intensify;
-it developed in the an area typical for the time of year (MDA)
-it was passing over a warm anomaly of SST due to the warm AMO (although the depth of this warmth (ocean heat content) was a little lower than typically needed for rapid intensification),
-perfect timing of the spike in MJO, which enhanced convection in that particular area. At the same time the activity decreased in the western Atlantic, with Humerto, Jerry and Karen fizzling out),
-low wind shear in the area due to the MJO and ENSO neutral conditions.
These factors were enough to overcome some dry air and marginal ocean heat content. The approach of the NW Atlantic trough later on helped vent the storm poleward and keep pressure lower than it otherwise have been as it accelerated towards the Azores.
The ECMWF forecasts the MJO to remain in Phase 1 for the next couple of weeks but at a lower amplitude than during September. The SST have reduced and the main development region retreats back west towards the Caribbean.
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