ATL: RINA - Post-Tropical - Discussion

[Sanibel]

meaning that it developed its spin at and even lower latitude farther east. stating that the reason for a lack of development is a lack of coriolis is inaccurate.

True, but the overall land-inhibition combined with weak coriolis is probably more accurate. Plus there's all sorts of dry air and deep-plunging troughs nearby.


It's weak but it's there. Sheared from the east. I think it will re-fire.

[cycloneye]

Yucatan Peninsula seems as the bullseye now rather than Nicaragua on 18z run of globals minus the bams.

[NDG]

This season has been a big lesson that until you have an established LLC that the models can latch onto it is difficult to trust any of them entirely. I think the vertical instability issue was a big one this year. What I can't understand is why with such a strong MJO pulse in our region can the vertical instability be so poor. Someone needs to study this season to find out what caused this to happen.

Agree 100%.Many studies have to be made to find out what occured in the 2011 North Atlantic season.

Vertical instability forecasts surely needs to be placed into the equation for future seasons' forecasts.
I am not even sure if there is such a thing as a long term forecast for vertical instability.

[psyclone]

meaning that it developed its spin at and even lower latitude farther east. stating that the reason for a lack of development is a lack of coriolis is inaccurate.

True, but the overall land-inhibition combined with weak coriolis is probably more accurate. Plus there's all sorts of dry air and deep-plunging troughs nearby.


It's weak but it's there. Sheared from the east. I think it will re-fire.

i agree with you there. the problem for the system is it's so close to nicaragua if it wanders west it'll be inland.

[SouthDadeFish]

Slowly coming together....

http://rammb.cira.colostate.edu/ramsdis ... _floater_2

The lower-level cloud deck is starting to fill in near the circulation center.

[gatorcane]

Game over... Hopefully for the rest of this annoying season.

See everybody in 2012. Strong cold front pushed through Florida which means end of rainy season and probably hurricane season for us.

[SouthDadeFish]

Everyone keep calling it game over when the circulation is looking as good as it ever has. I wouldn't give up on it yet.

[Ptarmigan]

I looked at the specific humidity and air temperature anomaly at the 300 millibar level for 2011 from August to September and compared it to 1995, 2005, and 2010 August to October. I noticed that the air is drier at the 300 millibar level in 2011, while it is wetter in 1995, 2005, and 2010. As for air temperature at the 300 millibar level, it is warmer than normal in 1995, 2005, 2010, and 2011.

300 Millibar Specific Humidity Anomaly





300 Millibar Air Temperature Anomaly

[ozonepete]

I looked at the specific humidity and air temperature anomaly at the 300 millibar level for 2011 from August to September and compared it to 1995, 2005, and 2010 August to October. I noticed that the air is drier at the 300 millibar level in 2011, while it is wetter in 1995, 2005, and 2010. As for air temperature at the 300 millibar level, it is warmer than normal in 1995, 2005, 2010, and 2011.

(See above for charts)

Very nice analysis, my friend. You've done half the homework for the NHC.

[ozonepete]

Game over... Hopefully for the rest of this annoying season.

See everybody in 2012. Strong cold front pushed through Florida which means end of rainy season and probably hurricane season for us.

A season like this is not likely to end until early December, regardless of the strength of the TCs produced.

[wxman57]

The threat to Florida continues to diminish. The slower it moves over the next 5 days, the more time for the strong front to reach the SE Gulf ahead of the disturbance. Models have all backed off on development, keeping the system near the northern Yucatan as the front arrives. Increasing wind shear ahead of the front should drive the moisture/remnants off to the northeast, possibly even south of the FL Peninsula next Friday. Too soon to rule out any enhance precip along the front in southern FL, though.

[ozonepete]

Hot towers over the LLC now...

[cycloneye]

Another run (18z) by GFS that has nothing.

[cycloneye]

A little bit more agressive in the language.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SAT OCT 22 2011

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

A LOW PRESSURE AREA IN THE SOUTHWESTERN CARIBBEAN SEA...LOCATED
ABOUT 200 MILES MILES SOUTHEAST OF THE NICARAGUAN/HONDURAN
BORDER...HAS CHANGED LITTLE DURING THE PAST SEVERAL HOURS. WHILE
THE SURFACE CIRCULATION IS BETTER DEFINED THAN IT WAS 24 HOURS
AGO...SHOWER AND THUNDERSTORM ACTIVITY REMAINS LIMITED. THIS
DISTURBANCE COULD STILL BECOME A TROPICAL DEPRESSION AS IT MOVES
SLOWLY NORTHWARD AND THEN NORTHWESTWARD INTO FAVORABLE
ENVIRONMENTAL CONDITIONS DURING THE NEXT COUPLE OF DAYS. THIS
SYSTEM HAS A MEDIUM CHANCE...50 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...
LOCALLY HEAVY RAINS AND GUSTY WINDS SHOULD CONTINUE TO PRIMARILY
AFFECT PORTIONS OF HONDURAS AND NICARAGUA THROUGH MONDAY.

[cycloneye]

00z Best Track

Pressure down to 1005 mbs and still moving slowly northward.

AL, 96, 2011102300, , BEST, 0, 135N, 814W, 25, 1005, LO

ftp://ftp.tpc.ncep.noaa.gov/atcf/tcweb/ ... 011.invest

[ozonepete]

A little bit more agressive in the language.

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT SAT OCT 22 2011

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

A LOW PRESSURE AREA IN THE SOUTHWESTERN CARIBBEAN SEA...LOCATED
ABOUT 200 MILES MILES SOUTHEAST OF THE NICARAGUAN/HONDURAN
BORDER...HAS CHANGED LITTLE DURING THE PAST SEVERAL HOURS. WHILE
THE SURFACE CIRCULATION IS BETTER DEFINED THAN IT WAS 24 HOURS
AGO...SHOWER AND THUNDERSTORM ACTIVITY REMAINS LIMITED. THIS
DISTURBANCE COULD STILL BECOME A TROPICAL DEPRESSION AS IT MOVES
SLOWLY NORTHWARD AND THEN NORTHWESTWARD INTO FAVORABLE
ENVIRONMENTAL CONDITIONS DURING THE NEXT COUPLE OF DAYS. THIS
SYSTEM HAS A MEDIUM CHANCE...50 PERCENT...OF BECOMING A TROPICAL
CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...
LOCALLY HEAVY RAINS AND GUSTY WINDS SHOULD CONTINUE TO PRIMARILY
AFFECT PORTIONS OF HONDURAS AND NICARAGUA THROUGH MONDAY.

I agree, Luis. I think they're going to have to get more aggressive later tonight and tomorrow. Regardless of where it ends up, I think this winds up at least a TS.

[Evil Jeremy]

This has a defined circulation decently offshore covered by waxing convection. IMO, TD:
http://www.ssd.noaa.gov/goes/flt/t1/flash-vis.html

[NDG]

Deep convection has been persistent in the NW quadrant of the low pressure for at least the last 12 hrs, with the possible LLC getting closer to the deep convection.
I place an X where clearly a COC is seen as well as it is placed in the latest 0z best track position.

[GCANE]

Starting to get a nice high rain-rate flare NW of the LLC.

Latest AMSU shows core temp profile somewhat compressed.

Let's see if the flare kicks it up to the 12km level.

[GCANE]

Anti-cyclone is to the NW of the LLC, pretty much right over the deep convection.

This could be the beginning of a ramp up phase.