MED: 02M/BLAS (HELIOS) - ex-Subtropical Storm

[Europa non è lontana]

The 06z and 12z GFS model runs, 12z ARPEGE run, 00z and 12z UKMet runs, 12z ICON run, 12z HIRLAM run, all have a currently frontal non-tropical low pressure system located about 300km south-east of Barcelona gain some tropical characteristics over the next 48 hours. It is difficult to predict its track beyond this time, as different models have widely different landfall solutions. It remains to be seen whether or not the low will gain tropical characteristics, as the environment is relatively hostile, but models suggest the possibility nonetheless.

[Vince_and_Grace_fan]

The latest models are tending toward a stronger system, most of them show a 45-50 kt storm now, however they vary in the size and structure (subtropical or tropical).

GFS:


ICON (German):


AROME:


ARPEGE, this also showed the best structure and the highest amount (~200-300 mm) of precipitation on the Balearic Islands as it forecasts the cyclone will meander in that area for 2-3 days:

[wxman57]

Air temps in the region are in the 50s, all the way down to Algeria, Tunisia, and northern Libya. This is clearly a non-tropical low in a cold airmass.

[Vince_and_Grace_fan]

It has a curved convective band on the eastern side, but the center is still attach to the fronts, and the overall develpoment seems slower than expected. The models also took back from the development, they show a much weaker and more disorganized system than yesterday and forecast more eastward movement toward Sardinia and Corsica.

[DanieleItalyRm]

Almost subtropical o tropical now?

https://twitter.com/PrometheiPlanum/status/1458730064011476995

[Europa non è lontana]

I'm inclined to think that the cyclone may be classifiable as subtropical now. It has had consistent convective activity around its centre for several hours, a shallow warm core, appears to be non-frontal, and has good radar presentation - please correct me if I'm wrong.

[DanieleItalyRm]

Yes. Hart shows various unresolved cyclones.He remembers that diagrams are an efficient way to analyze a cyclone but can sometimes not prove reality.This can especially happen in very small cyclones. Sure over the Atlantic, BLAS be classified to as a tropical or subtropical storm;

[Vince_and_Grace_fan]

Yes, it looks like a small subtropical storm now, however, the convection has weakened in the previuos hours. The satellite animation indicate that the low detached from the fronts, while a ASCAT-B pass at 10:29 UTC measured a small area of 35-40 kt winds on the western side of the circulation.

[Europa non è lontana]

ME, 02, 2021111112, 03, UKM, 0, 397N, 22E, 36, 1008, TS, 34, NEQ, 0, 0, 0, 40, , , 37, , , M, , , , , BLAS

[Sciencerocks]

eye forming

[tolakram]

Moved to active storms.

[DanieleItalyRm]

ME, 02, 2021111112, 03, UKM, 0, 397N, 22E, 36, 1008, TS, 34, NEQ, 0, 0, 0, 40, , , 37, , , M, , , , , BLAS

Link please?

[Europa non è lontana]

Link please?

https://www.wis-jma.go.jp/d/o/EGRR/Alphanumeric/Forecast/Miscellaneous/20211111/155800/A_FXXT04EGRR111558_C_RJTD_20211111160017_88.txt

[Vince_and_Grace_fan]

The latest ASCAT passes indicate some weakening.

ASCAT-A, 18:54 UTC:


ASCAT-B, 20:13 UTC:

[Sciencerocks]

Becoming fully tropical.

[DanieleItalyRm]

During the night a new eye characteristic just befor weakening:

[DanieleItalyRm]

BIG Image by Sentinel-3 ESA

[Vince_and_Grace_fan]

Althogh it had a bit more organized convection yesterday evening, I don't think the cyclone really became tropical. It still remained under influence of the large upper level low above, and evening ASCAT passes already suggested some connection with the exratropical low to east-northeast, which is more evident on satellite now and the convection alo became very disorganized (the cyclone is on the southern edge of the aimation below).
According to the models the cyclone could reorganize briefly in the night and early morning hours before conditions will become unfavorable again later tomorrow.

[DanieleItalyRm]

I believe that the small 02M cyclone has been isolated since yesterday, but the new depression is too big and close
so it necessarily affects on the small system 02M.

[Vince_and_Grace_fan]

I believe that the small 02M cyclone has been isolated since yesterday, but the new depression is too big and close
so it necessarily affects on the small system 02M.

Yes, but the isolation don't mean tropical status automatically, most of the subtropical storms also fully detached from the frontal zones, but still influenced by the upper level low/trough.

Late morning (10:09 UTC) ASCAT pass indicated that the cyclone totally merged with the other one and became an opened trough, however, models still forecast reorganization tonight.