Dr. Jeff Masters' WunderBlog

Last update for the night.. looking forward to watching the Zoo in the morning :)


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Daily Chuckles in Comments section

Quoting Orcasystems:


Nice place, I have been there many times :)

yea bloody cold right now though 42degrees here

Looking forward to Tim's forecast this morning.

Quoting homelesswanderer:


Would seem to gel with the graphic I posted.

Hi Homeless...

Quoting 7544:


this might help u

Link

thank you! it did help. have a good night all!

Quoting btwntx08:

holy wow

plus 1

later all iam out catch around 7 am

Where do you live Keep?

so ships sees a bright future for 91L taking it to H strength in 120hrs, TS in 24hrs
so TD soon?
it looks like a bit exaggerated, no? =P

It does seem a bit overdone JL..this one has to have you a little bit worried.

Been watching this blog for a while... lurking...

But Melor has been a beast...

NRl site has some good documentation of it; strangley holding on to Cat5/4 status well through its eye wall replacements.

Quoting GeoffreyWPB:
It does seem a bit overdone JL..this one has to have you a little bit worried.

yep a bit, but im relax until something actually actually forms :)

Keeper, lives in Toronto Canada.

Rain storm on the way across Sydney
Link

Goodnight all

JLPR---does look a little exaggerated--it has alot of work to do

Quoting Bordonaro:


I am not a meteorologist, but I understand what you're explaining. Cool.

But the $64,000 question is this, "If an ULL mimics the set-up or dynamics of a hurricane, but develops in 70F water, shouldn't it be considered a Hybrid/Sub-Tropical System"?

This is the way I interpreted the paper combined after hours of browsing the internet for other sources:

(1) Mature Extratropical Stage: At this stage, the surface extratropical cyclone features an occluded front, and has migrated beneath the center of an upper low (cold core).

(2) Subtropical cyclone stage: At this stage, the surface cyclone has separated from the occluded front and may feature a low-level warm core. If the upper-level low (cold core) allows for an unstable lapse rate, convection begins to develop, in some cases even over waters below 26 deg C. The convection triggers a more moist adiabatic lapse rate, which is even less stable. In the increasingly unstable atmosphere, air parcels increasingly rise, and low surface pressures are maintained or can fall.

(3) Tropical cyclone stage: At this stage, the convection has allowed for the development of a fully vertical warm core. The cyclone can continue to strengthen as long as it maintains deep convection, which allows for continued instability through super-moist adiabatic lapse rates.

The difference between stages (2) and (3) is how vertical deep the warm core is. The warm core is not involved in the strengthening process, just gives a signal of what stage its at. In both stages, the moist adiabatic lapse rate is dependent on the cyclone having a low central surface pressure such that it survives/strengthens.

Quoting NCHurricane2009:


This is the way I interpreted the paper combined after hours of browsing the internet for other sources:

(1) Mature Extratropical Stage: At this stage, the surface extratropical cyclone features an occluded front, and has migrated beneath the center of an upper low (cold core).

(2) Subtropical cyclone stage: At this stage, the surface cyclone has separated from the occluded front and may feature a low-level warm core. If the upper-level low (cold core) allows for an unstable lapse rate, convection begins to develop, in some cases even over waters below 26 deg C. The convection triggers a more moist adiabatic lapse rate, which is even less stable. In the increasingly unstable atmosphere, air parcels increasingly rise, and low surface pressures are maintained or can fall.

(3) Tropical cyclone stage: At this stage, the convection has allowed for the development of a fully vertical warm core. The cyclone can continue to strengthen as long as it maintains deep convection, which allows for continued instability through super-moist adiabatic lapse rates.

The difference between stages (2) and (3) is how vertical deep the warm core is. The warm core is not involved in the strengthening process, just gives a signal of what stage its at. In both stages, the moist adiabatic lapse rate is dependent on the cyclone having a low central surface pressure such that it survives/strengthens.

Thanks, believe or not, I understand that. If they allow systems like this to be considered TS, then the NHC/scientific textbook printing companies needs to consider changing SST threshold temperature. It's commonly taught that hurricanes need 80F SST to develop.

Quoting Bordonaro:


Thanks, believe or not, I understand that. If they allow systems like this to be considered TS, then the NHC/scientific textbook printing companies needs to consider changing SST threshold temperature. It's commonly taught that hurricanes need 80F SST to develop.

Yep, that paper on Hurricane Vince indeed suggests not using a SST threshold, but a lapse rate threshold.

im off to bed
night :0)

1022 Weather Student

2AM Yellow Circle

Quoting WeatherStudent:
The 2am TWO from the NHC will have 91L inside of which colored circle:

A: Yellow Circle
B: Orange Circle
C: Red Circle

Please, vote now

Polls close in 15 minutes.

I think B, Orange Circle

b

Quoting btwntx08:

B.

orange

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT MON OCT 5 2009

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON NEWLY-FORMED
TROPICAL STORM GRACE...LOCATED ABOUT 420 MILES NORTHEAST OF THE
AZORES.

1. A TROPICAL WAVE LOCATED ABOUT 1200 MILES EAST OF THE WINDWARD
ISLANDS IS PRODUCING A LARGE AREA OF DISORGANIZED SHOWERS AND
THUNDERSTORMS. SOME GRADUAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE
OVER THE NEXT COUPLE OF DAYS AS IT MOVES WESTWARD AT 15 TO 20 MPH.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS.

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

Yellow circle--waiting for a DMAX response--stabilization

Quoting AussieStorm:
Rain storm on the way across Sydney
Link

Glad to see it's Raining somewhere in AU,
I have heard it's a Terrible Drought down there, AussieStorm. Hope you get some more rain soon. Those huge dust storms I hear about look to be awful. I have a good friend up in Darwin NT, and some long lost relatives in Melbourne. At least the Cyclones have been clear of AU this year, right? Good Luck to our Australian pals from us "Yanks". W in Florida.

Yellow through tomorrow Pm

Good night folks from Mid-State TN. An interesting Tropical Weather week coming up!

TS Grace, the surprise TS will not live but 24-36 hrs.

TS Parma is gonna hang out in the S China Sea for 5 days, where's she gonna go?

Interesting to see if 91L develops and where she will go.

On Th 10-8-09, it will be very interesting to see how close TY Melor will get to Japan.

JTWC forecasts the center of TY Melor to pass within 25NMI of Japan's coast, as an 75KT TY near or just N of the Tokyo Metro area, which has an approx. population of 30,000,000 people on 10-8-09 shortly after 0800 UTC.

From 2006-

moderate shear, with trouble ahead

WS--- think so?

As much as I respect the NHC, 91L lools like at least an orange. Ive seen them use orange and red on worst looking systems!! Oh well!

91 L looks good for now, but NHC is notorious for waiting...that thing has alot of things to overcome--even massive blocking from North America, which keeps us all safe for now

Quoting CatFiveLove:
91 L looks good for now, but NHC is notorious for waiting...that thing has alot of things to overcome--even massive blocking from North America, which keeps us all safe for now

What about the Antillies and Carribean?

Quoting archer312:


Glad to see it's Raining somewhere in AU,
I have heard it's a Terrible Drought down there, AussieStorm. Hope you get some more rain soon. Those huge dust storms I hear about look to be awful. I have a good friend up in Darwin NT, and some long lost relatives in Melbourne. At least the Cyclones have been clear of AU this year, right? Good Luck to our Australian pals from us "Yanks". W in Florida.

Our Cyclone season starts November 1 till March 30.
Took a fair few pics of the storm as it was approaching they will be up in my blog soon.

Quoting tornadodude:
From 2006-

Isn't that Cyclone Hamish???

shear over antilles--with winds out of east--looks like head chopping material

correction east=west

what am I doing up, no idea XD
but 91L is looking good although convection still hasnt consolidated, several blobs of convection there



now im off to hit my head with a bat, then maybe I will finally be able to sleep lol

Some decent shear in 91Ls path. Probably why none of the models are too crazy about this system. ECMWF has it turning into an open wave. It is the 2009 hurricane season after all. The year of disturbances going POOF just when they look like they might start cranking up.

Quoting markymark1973:
Some decent shear in 91Ls path. Probably why none of the models are too crazy about this system. ECMWF has it turning into an open wave. It is the 2009 hurricane season after all. The year of disturbances going POOF just when they look like they might start cranking up.

"year of the disturbances going poop" agreed