[P.K.]

Expect advisories on 40kt TS Alberto to begin in the next hour.

[Martyn Wells]

Beat me to it yes.

Tidy and tight looking system.

[P.K.]

Assuming they sort out 92L which everyone pretty much agreed should have been named either subtropical or tropical post season then we have two named storms by 19th May which is quite something!

[Martyn Wells]

Yes I'd agree this should be the B... However if it does get named retrospectively what would it get called?

I think that will be part of NHCs post season review

[P.K.]

Unnamed Tropical/Subtropical Storm like this http://www.nhc.noaa....011_Unnamed.pdf.

[P.K.]

I'm told according to the HURDAT only 1887 had two named storms by this date.

[P.K.]

45kt peak.

WTNT21 KNHC 192034
TCMAT1

TROPICAL STORM ALBERTO FORECAST/ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL012012
2100 UTC SAT MAY 19 2012

TROPICAL STORM CENTER LOCATED NEAR 32.2N 77.7W AT 19/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE SOUTHWEST OR 220 DEGREES AT 3 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1007 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 40NE 0SE 30SW 40NW.
12 FT SEAS.. 0NE 90SE 0SW 40NW.
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 32.2N 77.7W AT 19/2100Z
AT 19/1800Z CENTER WAS LOCATED NEAR 32.3N 77.6W

FORECAST VALID 20/0600Z 31.9N 78.1W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 40NE 0SE 30SW 40NW.

FORECAST VALID 20/1800Z 31.7N 78.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 40NE 0SE 30SW 40NW.

FORECAST VALID 21/0600Z 31.9N 78.9W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 50NE 20SE 30SW 40NW.

FORECAST VALID 21/1800Z 32.7N 78.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 50NE 30SE 20SW 40NW.

FORECAST VALID 22/1800Z 34.5N 75.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 50NE 40SE 20SW 40NW.

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 23/1800Z 37.5N 72.0W...POST-TROP/EXTRATROP
MAX WIND 40 KT...GUSTS 50 KT.

OUTLOOK VALID 24/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 32.2N 77.7W

NEXT ADVISORY AT 20/0300Z

$$
FORECASTER BRENNAN

[P.K.]

On the record at the bottom, Aletta actually formed at 00Z on the 15th May which isn't pre-season.

WTNT41 KNHC 192042
TCDAT1

TROPICAL STORM ALBERTO DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL012012
500 PM EDT SAT MAY 19 2012

SATELLITE...RADAR...AND SURFACE DATA INDICATE THAT THE SMALL SURFACE
LOW LOCATED OFF THE COAST OF SOUTH CAROLINA HAS ACQUIRED THE
CHARACTERISTICS OF A TROPICAL CYCLONE. ORGANIZED DEEP CONVECTION
HAS BEEN PERSISTENT OVER THE CENTER FOR MORE THAN 18 HOURS...AND
THE CIRCULATION CENTER HAS BEEN MOVING SOUTH AWAY FROM AN AIRMASS
BOUNDARY THAT EXTENDS ROUGHLY ALONG 33N. BASED ON AN ASCAT PASS
FROM AROUND 1530 UTC...THE INITIAL INTENSITY IS SET AT 40 KT.
ALBERTO IS SITUATED IN A MARGINAL THERMODYNAMIC ENVIRONMENT FOR
STRENGTHENING...WITH A MARKEDLY DRY CONTINENTAL AIRMASS TO ITS NORTH
AND WEST OVER THE EASTERN CAROLINAS. GIVEN THIS...ONLY MODEST
INTENSIFICATION IS EXPECTED DESPITE THE CYCLONE BEING OVER
THE RELATIVELY WARM GULF STREAM. ALBERTO IS EXPECTED TO BECOME
EXTRATROPICAL BY 96 HOURS...AND SHOULD DISSIPATE BY DAY 5. THE NHC
INTENSITY FORECAST IS A BLEND OF THE MORE AGGRESSIVE STATISTICAL
GUIDANCE AND THE WEAKER DYNAMICAL MODELS.

THE LOW-LEVEL CIRCULATION IS A BIT TO THE EAST OF THE COLDEST CLOUD
TOPS AND THE CIRCULATION CENTER SEEN ON RADAR...AND THE INITIAL
MOTION ESTIMATE IS 220/03. THE SYNOPTIC ENVIRONMENT IS COMPLEX...AS
ALBERTO IS IN A REGION OF WEAK STEERING FLOW WITHIN A BROAD
MID/UPPER-LEVEL TROUGH. THE NHC FORECAST SHOWS A SLOW SOUTHWESTWARD
MOTION OVER THE NEXT DAY OR SO DUE TO THE STRONG NORTHEASTERLY FLOW
BETWEEN A SURFACE RIDGE EAST OF THE APPALACHIANS AND A LARGER
EXTRATROPICAL LOW CENTERED NEAR 36N/72W. AS THAT LOW MOVES WESTWARD
AND WEAKENS BY SUNDAY NIGHT...ALBERTO IS EXPECTED TO TURN NORTHWARD
AND THEN ACCELERATE NORTHEASTWARD AFTER 48 HOURS AS A SHORTWAVE
TROUGH MOVES INTO THE EASTERN UNITED STATES AND THE STEERING FLOW
BECOMES SOUTHWESTERLY. GIVEN THE SMALL SIZE OF ALBERTO AND THE
COMPLEX STEERING PATTERN...IT IS NOT SURPRISING THAT THE TRACK
MODEL GUIDANCE SHOWS A LARGE AMOUNT OF SPREAD...BOTH IN TERMS OF
HOW FAR SOUTH AND WEST ALBERTO WILL MOVE...AND HOW SHARP THE TURN
TOWARD THE NORTHEAST WILL BE. THE NHC TRACK FORECAST IS GENERALLY
CLOSE TO THE TVCA MULTI-MODEL CONSENSUS...AND IS OF VERY LOW
CONFIDENCE.

A TROPICAL STORM WATCH COULD BE REQUIRED FOR A PORTION OF THE COAST
OF THE CAROLINAS THIS EVENING.

ALBERTO IS EARLIEST-FORMING TROPICAL STORM IN THE ATLANTIC BASIN
SINCE ANA IN 2003. THIS IS ALSO THE FIRST TIME THAT A TROPICAL
STORM HAS FORMED BEFORE THE OFFICIAL START OF THE HURRICANE SEASON
IN BOTH THE ATLANTIC AND EAST PACIFIC BASINS.


FORECAST POSITIONS AND MAX WINDS

INIT 19/2100Z 32.2N 77.7W 40 KT 45 MPH
12H 20/0600Z 31.9N 78.1W 45 KT 50 MPH
24H 20/1800Z 31.7N 78.5W 45 KT 50 MPH
36H 21/0600Z 31.9N 78.9W 45 KT 50 MPH
48H 21/1800Z 32.7N 78.5W 45 KT 50 MPH
72H 22/1800Z 34.5N 75.5W 45 KT 50 MPH
96H 23/1800Z 37.5N 72.0W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 24/1800Z...DISSIPATED

$$
FORECASTER BRENNAN

[Dave W]

Aletta categorised at 00Z but did it form a bit before?

[P.K.]

Well yes but it was named at 00Z which is what is used for record purposes.

[ldavidcooke]

Hey Peter,

I know I should not chat/editorialize here; however, as NOAA has issued a "Final", I wanted to share that I do not necessarily agree with naming any old whirling convection in/and about the end of May.

Based on the 250mb windfield both 92L and Alberto were spawns of N. Jetstream troughs and as such really need to be considered as extra-tropical in origin, IMHO. Similar to what I and others have shared in the past, these types of storms have significantly unique origins and similar to an EF-0/1 whirlwind, should not be classed with the "lethal" Cyclones, (Maybe I misunderstand the function of the SPC and NHC?). Though they had taken on sub-tropical characteristics, they did not originate via the E->W equatorial ITCZ (<@20 deg. N) circulation.

I suspect that originating as cold core and having insufficient surface thermal resources will limit both their potential and strength, putting them more in the US Nor' Easter storm class then TC... However, as always you fellows are the Experts I grant, you know best... I just do not understand why everything has to fall under the same catagorization when there are clear classification/origination differences.

PS: I think I found my own answer. Apparently the Nor' Easters that "crossed the pond" were called "European Windstorms" with a naming structure similar to the Western N. Atlantic. The agreement to merge systems; to bring all naming/tracking systems together and to reduce maritime or aeronautic confusion, forced all N. Atlantic storms to fall under a common set of guidelines. As such, this changes the naming/classification standards.

[Martyn Wells]

This was a warm core storm, with a well defined LLCC and aligned mid level rotation. Convective banding, organised around the centre presented a true Dvorak classification of a tropical storm. Quikscat passes showed a defined and broadly circular wind field, and surface winds greater than tropical storm force.

The origins really do not matter, generally only 66-75% of Atlatic tropical systems are spawned by tropical waves...

[ldavidcooke]

Hey Martyn,

Thanks, I was aware that it had developed over the ocean; yet, I thought it had non-tropical origins. For us in the SE US for the past 40 years I thought I could count the non-tropical TSs and Hurricanes where the convection reached the 300mb range and an anti-cyclonic capped it off, on one hand... (Must be CRS setting in..., or maybe its just low blood flow...)

[P.K.]

ldavidcooke, on 22 May 2012 - 17:19, said:

Hey Peter,

I know I should not chat/editorialize here; however, as NOAA has issued a "Final", I wanted to share that I do not necessarily agree with naming any old whirling convection in/and about the end of May.

PS: I think I found my own answer. Apparently the Nor' Easters that "crossed the pond" were called "European Windstorms" with a naming structure similar to the Western N. Atlantic. The agreement to merge systems; to bring all naming/tracking systems together and to reduce maritime or aeronautic confusion, forced all N. Atlantic storms to fall under a common set of guidelines. As such, this changes the naming/classification standards.

No that is fine. We've just had a very quick start to the year with one TC and another probable one. The NE Pac season has also started at record breaking pace.

I don't know when the Germans first started naming storms, I doubt it was that long ago. TCs in the N Atl have been named since the 1950s when they used the phonetic alphabet before moving onto proper names.

[Martyn Wells]

Hey David

What, exactly, is a non tropical hurricane?

All tropical hurricanes top out at 300mb or higher and have an upper anti-cyclone aloft to aid the huge outflow created.

Am I having a blonde day?

[ldavidcooke]

Hey Martyn,

No, your not blonde, it is the difference in references and poor communication on my part.

A non-tropical Hurricane would be a cold core spawned low center that when moves over warm ocean water above 25 deg. N develops a rotating 300-250mb convective plume and an anti-cyclonic upper air feature which goes into feeding/self peputuating its own environment.

I believe where I get confused is where I see a Nor' Easter (or what would have been called a European Windstorm), I believe you would likely call it a (extra/sub)-tropical TC. (To my knowledge, here on this side we didn't name non-land crossing gales/storms...)

[Martyn Wells]

Aha! So basically mid lattitude bog standard barometric based low pressure systems?

We call them low pressure systems and avoid the terminology hurricane, which caused huge controversy in 1987 when a major storm crossed the uk. Google Michael Fish (who also now forecasts over on Netweather) and 1987 to find out why, if you don't know.

But basically if it's barometric, NHC refer to a system as extra tropical as it has lost all warm cored tropical characteristics (or never had them). If its barotrophic, warm cored, and with banded organised convection around a defined LLCC, it looks and smells tropical.

[ldavidcooke]

Hey Martyn,

It would seem so, only the one I am describing has < 1000-@500mb convection, surrounding a rotating core that out flows via a weak upper level high pressure (between 400-300mb). It still has a weak envelopment; however, it usually has an occluded center and forms north of the N. Jetstream circulation. How is that different from what you are describing? (BTW, I found the term European Windstorm, as a description in wiki, so I do not know that is a proper term... Here: http://en.wikipedia....opean_windstorm )

[Martyn Wells]

Yep that'll be frequent visitor to these shores

[ldavidcooke]

Hey Martyn,

Well that certainly helps with my understanding of the dfferences in why I do not see a name trigger where as the Eastern shores might. Where we have had some damage from a Not' Easter though even if it develops tropical characteristics, it would not seem necessary to name, as most go fish, with most of the energy primarily being down wind. Europe on the other hand, is up wind the energy and as such the Lee shore sees nearly Cat. 1 damage, hence naming becomes important for maritime and preperation tracking purposes. Thanks for takng the time to explain and allowing me to explore the differences in perception here.