Possible development in Central Atlantic (Is invest 98L)

[cycloneye]

As Yogi Berra said,is not over until it's over. Maybe we have the 13th named storm being Tropical or Subtropical?

A LOW PRESSURE AREA IS EXPECTED TO FORM BY EARLY NEXT WEEK OVER THE
ATLANTIC OCEAN BETWEEN BERMUDA AND THE AZORES. CONDITIONS COULD
BECOME CONDUCIVE FOR SOME DEVELOPMENT AS THE LOW MOVES GENERALLY
NORTHWARD...AND THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF
BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT FIVE
DAYS.

[Hammy]

I've been seeing something forming in the model runs now for several days, both the Euro and GFS showing something developing. So it seems what I was seeing may very well be tropical.

[cycloneye]

12z GFS:

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
700 PM EST FRI NOV 15 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

OTHER SYSTEMS WITH FORMATION POTENTIAL BEYOND 48 HOURS...

A NON-TROPICAL AREA OF LOW PRESSURE IS EXPECTED TO FORM OVER THE
CENTRAL ATLANTIC OCEAN THIS WEEKEND. ENVIRONMENTAL CONDITIONS COULD
BECOME CONDUCIVE FOR THIS SYSTEM TO GAIN SUBTROPICAL
CHARACTERISTICS EARLY NEXT WEEK AS THE LOW MOVES GENERALLY
NORTHWARD. THIS SYSTEM HAS A LOW CHANCE...20 PERCENT...OF BECOMING
A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT FIVE DAYS.

&&

FIVE-DAY FORMATION PROBABILITIES ARE EXPERIMENTAL IN 2013. COMMENTS
ON THE EXPERIMENTAL FORECASTS CAN BE PROVIDED AT...

HTTP://WWW.NWS.NOAA.GOV/SURVEY/NWS-SURVEY.PHP?CODE=ETWO

$$
FORECASTER CANGIALOSI

[hurricanes1234]

Great! I love subtropical storms (providing Bermuda isn't affected). They are unique and are open, with areas of popcorn convection. What intensities are the models hinting?

[Hammy]

What intensities are the models hinting?

12z Euro is showing <1000mb and GFS looks about 980mb.

[galaxy401]

I thought we would still be some possible subtropical development in November. Not expecting much though.

[Ntxw]

Think it's unlikely. What the Euro is showing is cold core, 850s are cold and 500mb heights are low. Same with the latest GFS, you're talking sub 564dm heights at 5h which is almost winter storm like.

[Hammy]

Think it's unlikely. What the Euro is showing is cold core, 850s are cold and 500mb heights are low. Same with the latest GFS, you're talking sub 564dm heights at 5h which is almost winter storm like.

The graphics at the top of the page do show this as a shallow warm core system later. If things do indeed get going it appears it will be an extratropical to tropical transition, probably a few days after the low forms.

edit: NHC is up to 40% for five day chances.

[TropicalAnalystwx13]

The prospects of Melissa look quite high to me. Whatever develops will start off subtropical but will have the potential to become fully tropical over warm sea surface temperatures in a low wind shear environment.

[supercane4867]

10/40%

A NON-TROPICAL LOW PRESSURE SYSTEM IS DEVELOPING OVER THE CENTRAL
ATLANTIC OCEAN SEVERAL HUNDRED MILES TO THE SOUTHEAST OF BERMUDA.
ENVIRONMENTAL CONDITIONS COULD BECOME CONDUCIVE FOR THIS SYSTEM TO
GRADUALLY ACQUIRE SUBTROPICAL CHARACTERISTICS OVER THE WEEKEND AND
INTO EARLY NEXT WEEK AS THE LOW MOVES GENERALLY NORTHWESTWARD. THIS
SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A SUBTROPICAL OR
TROPICAL CYCLONE DURING THE 48 HOURS...AND A MEDIUM CHANCE...40
PERCENT...OF BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE
NEXT FIVE DAYS.

[Ntxw]

Think it's unlikely. What the Euro is showing is cold core, 850s are cold and 500mb heights are low. Same with the latest GFS, you're talking sub 564dm heights at 5h which is almost winter storm like.

The graphics at the top of the page do show this as a shallow warm core system later. If things do indeed get going it appears it will be an extratropical to tropical transition, probably a few days after the low forms.

edit: NHC is up to 40% for five day chances.

I don't know how that graph is done, but that is not what I am seeing from the models in fact quite opposite. It's showing it becomes more warm core as it moves further north? Doesn't make sense to me this time of year. Take a look at 0z GFS, this is not warm core. It may start out as something subtropical or maybe tropical but quickly changes cold core as it becomes a trough as it moves NW. You just don't associate that kind of low heights to a tropical system, extratropical.

[cycloneye]

10%/50%

A NON-TROPICAL LOW PRESSURE SYSTEM IS GRADUALLY DEVELOPING OVER THE
CENTRAL ATLANTIC OCEAN SEVERAL HUNDRED MILES TO THE SOUTHEAST OF
BERMUDA. ENVIRONMENTAL CONDITIONS COULD BECOME CONDUCIVE FOR THIS
SYSTEM TO GRADUALLY ACQUIRE SUBTROPICAL OR TROPICAL CHARACTERISTICS
LATER THIS WEEKEND OR EARLY NEXT WEEK AS THE LOW MOVES
NORTHWESTWARD TO NORTHWARD. THIS SYSTEM HAS A LOW CHANCE...10
PERCENT...OF BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE
48 HOURS...AND A MEDIUM CHANCE...50 PERCENT...OF BECOMING A
SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT FIVE DAYS.

[cycloneye]

12z GFS has it Subtropical at 87 hours.

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
100 PM EST SAT NOV 16 2013

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

A NON-TROPICAL LOW PRESSURE SYSTEM CONTINUES TO GRADUALLY DEVELOP
OVER THE CENTRAL ATLANTIC OCEAN SEVERAL HUNDRED MILES TO THE
SOUTHEAST OF BERMUDA. ENVIRONMENTAL CONDITIONS COULD BECOME
CONDUCIVE FOR THIS SYSTEM TO ACQUIRE SUBTROPICAL OR TROPICAL
CHARACTERISTICS EARLY NEXT WEEK WHILE THE LOW MOVES NORTHWESTWARD
TO NORTHWARD. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF
BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE 48
HOURS...AND A MEDIUM CHANCE...50 PERCENT...OF BECOMING A
SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT FIVE DAYS.

[cycloneye]

The environment looks good for this to develop.

[hurricanes1234]

Could we get a subtropical hurricane out of this? By the way, I saw that the strongest winds in a subtropical cyclone were 75 mph, meaning it was at hurricane strength. What cyclone was this?

[Iune]

It was Subtropical Storm One of 1979 (http://en.wikipedia.org/wiki/1979_Atlantic_hurricane_season#Subtropical_Storm_One)

[TropicalAnalystwx13]

Set these links up:

Visible Loop

Water Vapor Loop

Infrared Loop

[hurricanes1234]

Thanks for the answer. Hopefully it can get itself organised and named before some unexpected shear or something else sets in. Also, I find it very peculiar that the shear is so low that far north, well in the westerlies.