Hurricane Alex

[Vorticity0123]

The 2016 Atlantic hurricane season has made a very early start! Over relatively cool, 22 degrees waters south of the Azores, subtropical storm Alex has taken shape. This is the first occurrence of such event since 1978! Alex is forecast to move northwards and get absorbed into a low pressure area north of the Azores later on. In the long term it may have some implications on the weather in Western Europe in the midlatitudes.

Track forecast of hurricane Alex.

See this link for the forecast discussion. Interesting stuff to say the least!

[Nouska]

Thanks Vorticity - was hoping someone had recorded this unusual event.

Previous tropical cyclones in January.

 

 

And also this first combo in January.

Eric Blake ‏@EricBlake12 · 25m25 minutes ago

Eric Blake Retweeted NHC Atlantic Ops
It is flat-out ridiculous that NHC & CPHC are writing advisories at the same time in January- first time on record! 

[Somerset Squall]

This is the fourth incidence if a named storm FORMING in January (others have persisted into January), so this gives you an idea of just how rare Alex's formation is. And yes, quite incredible with the Central Pacific Hurricane Pali still active too. And the Western Pacific is quiet. If there is any northern hemisphere basin out of the 4 you would expect to see a tropical or subtropical cyclone in January, it would be the Western Pacific. Certainly not the Central Pacific or the Atlantic!

 

 

[knocker]

Latest GEFS for track

[Vorticity0123]

So we seriously have a hurricane in the Atlantic ... in January! Just insane, the first time a hurricane has formed in January there since 1938. https://en.wikipedia.org/wiki/1938_Atlantic_hurricane_season

 

Satellite image of hurricane Alex.

This system also has the looks of a hurricane with a very clear eye visible as well. Even though it is over waters much colder than the usual 27*C threshold often seen with tropical storms, it is a healthy-looking hurricane. However, as is often seen with such storms over cold waters, the convection is not as deep as one normally would expect. This is nicely illustrated in a DVORAK image of Alex.

Dvorak satellite image of Alex. Note the relatively shallow convection surrounding the eye.

A good read about this system and its unusual traits can be found here: http://www.wunderground.com/blog/JeffMasters/unprecedented-simultaneous-january-named-storms-in-the-atlantic-and-c?MR=1

[Somerset Squall]

We need to be careful with terminology here. Alex is being classified as a 60kt subtropical storm. Whilst it may look like a hurricane, it is not classified as one. Though it is a damn good looking subtropical storm I have to say!

[Vorticity0123]

18 minutes ago, Somerset Squall said:

We need to be careful with terminology here. Alex is being classified as a 60kt subtropical storm. Whilst it may look like a hurricane, it is not classified as one. Though it is a damn good looking subtropical storm I have to say!

True, it has not yet been designated as being one by the NHC, but according to various sources it has officially already reached 75 knots. For example:

http://www.tropicaltidbits.com/storminfo/

Also, some more official sites are calling this a hurricane with 75 kt winds:

http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?storm_identifier=AL012016

So this would suggest that Alex is officially also a hurricane

 

Officially this information should be retrieveable via an ATCF document, but I am unable to find it so far.

[Nouska]

Official now...

...ALEX BECOMES A HURRICANE... ...HURRICANE WARNING ISSUED FOR THE AZORES...

11:00 AM AST Thu Jan 14
Location: 31.5°N 28.4°W
Moving: NNE at 20 mph
Min pressure: 981 mb
Max sustained: 85 mph


000
WTNT41 KNHC 141434
TCDAT1

HURRICANE ALEX DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL012016
1100 AM AST THU JAN 14 2016

Remarkably, Alex has undergone the transformation into a hurricane.
A distinct eye is present, embedded within a fairly symmetric mass
of deep convection. Water vapor imagery shows that the upper-level
trough is now west of the cyclone, with divergent flow over the
center - indicative of a tropical transition. It is very unusual to
have a hurricane over waters that are near 20 deg C, but the
upper-tropospheric temperatures are estimated to be around -60 deg
C, which is significantly colder than the tropical mean. The
resulting instability is likely the main factor contributing to the
tropical transition and intensification of Alex. With these
changes, the government of the Azores has issued warnings for most
of the Azores islands.

The initial intensity is set to 75 kt in accordance with the
analyzed Dvorak T-number of 4.5. Only slight additional
intensification seems possible since the system will be passing
over even colder waters during the next day or two. In 36 hours,
the global models suggest that the cyclone will become
extratropical as it begins to merge with a large low pressure area
at high latitude. The post-tropical cyclone is then likely to lose
its identity after 48 hours.

The initial motion is north-northeastward or 020/17 kt. Alex is
being steered by a shortwave mid-level trough that is rotating
around a larger trough to the northwest. This should cause the
cyclone to turn northward and north-northwestward and accelerate
over the next couple of days. The official track forecast is very
similar to the previous one and also quite close to the consensus
of the tightly-packed dynamical model forecast tracks.

Alex is the first hurricane to form in the month of January since
1938, and the first hurricane to occur in this month since Alice of
1955.

FORECAST POSITIONS AND MAX WINDS

INIT 14/1500Z 31.5N 28.4W 75 KT 85 MPH
12H 15/0000Z 34.3N 27.7W 80 KT 90 MPH
24H 15/1200Z 38.9N 27.7W 75 KT 85 MPH
36H 16/0000Z 45.3N 28.6W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 16/1200Z 53.0N 31.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 17/1200Z...DISSIPATED

$$
Forecaster Pasch

[reef]

Topic title changed to reflect Alex being a hurricane. A bit early for all this I must say!

[Summer Sun]

Another unusual January hurricane forms

http://blog.metoffice.gov.uk/2016/01/14/another-unusual-january-hurricane-forms/

[Somerset Squall]

Wow, and forecast to peak at 80kts! That's some cold and unstable air aloft to support such a system over cold waters such as Alex is over. Wow!!!

[lorenzo]

Nice article from NASA here http://www.nasa.gov/feature/goddard/2016/alex-atlantic-ocean

Here's a couple of things lifted from it

 

 

Between this and the models ( at all levels) - this week is proper madness, you take a break from looking at stuff for 2 days and come back and everything is insane. Where to begin lol !

 

[Dr. Astro]

Latest...

 

HURRICANE ALEX DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012016 500 PM AST THU JAN 14 2016 Alex has been maintaining a fairly impressive appearance on satellite imagery, with a well-defined 15-20 n mi diameter eye embedded within cold cloud tops. Recent images do suggest some warming/erosion of the tops over the southwest quadrant. Dvorak T-numbers remain near 4.5 so the current intensity is held at 75 kt. Sea surface temperatures are now below 20 deg C and should continue to cool along the path of Alex. This, along with a little increase in southwesterly shear, should result in gradual weakening. However, Alex is expected to maintain hurricane strength while passing near or over the Azores. In 24 hours or so, the global models show a distinct warm front over the northeast portion of the circulation. This suggests extratropical transition, and the official forecast reflects this. Later in the forecast period, the global models show the system merging with another extratropical cyclone over the northern Atlantic. The initial motion is slightly east of due northward or 015/19. There is essentially no change to the track forecast reasoning. Alex continues to be steered by the flow of a shortwave mid-tropospheric trough that has been rotating around a broader trough to its northwest. This evolution should cause the cyclone to turn gradually to the left with increasing forward speed over the next couple of days. The dynamical track guidance models are in excellent agreement for the first 36 hours of the forecast, and the official forecast is near the consensus of these models. This is basically an update of the previous NHC track prediction. Alex's wind field is likely to expand as it nears and makes the extratropical transition. The wind radii forecasts are based primarily on guidance from the NOAA Ocean Prediction Center.

[Eskimo]

I'm actually quite amazed that a hurricane can form at just 1000mb. You tend to assume that hurricanes are <950mb. 

[Methuselah]

Me too, PS - the storm that sunk the Braer was a stonking 916 mb!

[Chris W]

Incredible, a January hurricane over cold waters!  This system will be great to watch.

[Gael_Force]

Now that extratropical  transition nears and presentation degrades, a nice infrared satellite picture  from yesterday - the first January hurricane in the Atlantic basin, in the satellite era!

Extract from the latest NHC discussion ....

The overall convective pattern of Alex has continued to erode since
the previous advisory. However, conventional and microwave satellite
imagery indicate that there is still enough inner-core convection
and a small radius of maximum winds to warrant keeping Alex as a
hurricane for this advisory. Satellite classifications continue to
decrease, and the initial intensity has been lowered to 65 kt based
on a blend of the TAFB current intensity estimate of T4.5/77 kt and
a current T-number of T3.5/55 kt.

Alex has yet to make the turn toward due north, and the initial
motion estimate is 005/20 kt. Other than to nudge the forecast track
slightly to the right based on the more eastward initial position,
there are no significant changes to the previous forecast track or
reasoning.

(...)

http://www.nhc.noaa.gov/text/refresh/MIATCDAT1+shtml/150846.shtml

[Summer Sun]

 

 

 

[Sainsbo]

Looking a bit rough on Satellite imagery now, but nonetheless I wasn't expecting to be posting in an Atlantic Hurricane thread in january this year!

 

Despite the SST's being only in the low 20's - which is usually too low to aid tropical cyclone development, it looks like unusually cold air in the upper troposphere provided some more favourable conditions for this to take place.

 

It didn't look bad for a weak Cat.1 either, to think sometimes we are months into the hurricane season before we see a storm with a eye that's defined enough to see on visible imagery

 

 

[SNOW_JOKE]

Interesting that the NHC has it down as a Hurricane again in the mid-atlantic for the next couple of days...

[Somerset Squall]

Alex is now extratropical. The remnant low is forecast to deepen over the next day or so, and will indeed have sustained winds of hurricane force. However, Alex is no longer actually a hurricane.

Amazing system! Something that caught me completely off guard, and a lot of other people too. I remember model runs indicating this low to form, and reading that people were hypothesising this low would be extratropical. No-one expected a fully fledged hurricane, and a decent looking one at that! One for the history books. And there is bound to be a lot of study going into Alex and it's formation. I absolutely love when quirky things like this happen, it's fascinating, especially when it shocks us all like this hurricane has.