Dr. Jeff Masters' WunderBlog

Quoting KoritheMan:


Upper-level outflow does have shearing within it, so you are somewhat correct. But outflow in itself does not shear the TC that is producing the outflow.

Outflow will, however, shear other developing disturbances, as was the case with Hurricane Fran's outflow destroying Tropical Storm Gustav in 1996. Had it not been for that, Gustav would've probably been a major hurricane.

To add to this in order to help serial out some more, along with any others, outflow aloft flows anticyclonically, so remember that if you are ever making a forecast of which direction the shear will come from when upper-level outflow shears another system.

Quoting Hurricane009:
It is not a Tropical Wave, it is a tropical depression. :)

oh yeah whoops sorry xD
my brain died for a minute there lol xD

Looks like the cooler/fall like weather comes into the SE USA after that low makes landfall and heads NE according to the 18Z GFS....

Quoting justmehouston:
Hey Ike, got a question for you. I just looked at the shear map that you posted for the GOM. Here's the question ...everytime that I push the +1 what does that equal in time?

6 hours.

Quoting SykKid:
boring

Lives are not being ruined, though with that comment, perhaps... Nevermind.

Thanks Ike and thanks to Patrap for answering my earlier questions

something interesting

Finally, around midday on September 1, the NHC initiated advisories on Tropical Storm Erika, skipping depression status; the second storm of the year to do so.

Quoting KoritheMan:


Upper-level outflow does have shearing within it, so you are somewhat correct. But outflow in itself does not shear the TC that is producing the outflow.

Outflow will, however, shear other developing disturbances, as was the case with Hurricane Fran's outflow destroying Tropical Storm Gustav in 1996. Had it not been for that, Gustav would've probably been a major hurricane.

Thanks 456 and kori for answering... Those were pretty active seasons! I was looking back to the 1995 days ago where Luis, Jeane, Humberto, Iris were simultaneous.

Quoting KoritheMan:


To add to this in order to help serial out some more, along with any others, outflow aloft flows anticyclonically, so remember that if you are ever making a forecast of which direction the shear will come from when upper-level outflow shears another system.

I'm trying to get my head around that!

Quoting justmehouston:
Thanks Ike and thanks to Patrap for answering my earlier questions

You're welcome.

Quoting SykKid:


I want a Hurricane to track....Dont recall saying anything about lives being ruined?

You have TD7. It will probably become a hurricane due to that anticyclone. Isn't that enough?

Holy macrel it's wet here in eastern NC. Some guy flipped a boat in the middle of US70 this afternoon. Maybe he was just preparing for these conditions....

Quoting Hurricane009:
What is TD 7 's T#

SAB = 2.0
TAFB = 2.5

07L would be more interesting if he drifted his way into the Central Atlantic. I know there are alternatives, but I prefer the satellite on the NHC page.

Quoting SykKid:


It's not forcasted to become a Hurricane....Once it dies....there is nothing.

And we know all forecast are set in stone, right ST?

Quoting BurnedAfterPosting:
I disagree about all that shear, I think we will see close to home activity at the end of September and into October

It is definitely possible

also not possible

I am going slightly above the NHC intensity guidance, I think TD 7 could come close to be Hurricane Fred briefly.

Quoting SykKid:


It's not forcasted to become a Hurricane....Once it dies....there is nothing.

It's okay to go above the pros sometimes. In this case, that's what 456 and I are doing. The anticyclone should persist for at least three and a half days.

Quoting StormW:


Outflow from a system will also stifle a system that is close enough, as the outflow, being anticyclonic, begins to sink away from the storm. This sort of puts a "cap" on a system near enough, as the sinknig motion doesn't allow for an outflow to establish with a second system that is too close to a developed system.

Learn something new everyday. Thanks!

No one is right 100% of the time. The models are definetly not right 100% of the time either.

One thing the NHC always seem to sy is that we do not know that much about intensity. Once there is an established system, they are decent at track - but not whether it will fall apart or strengthen, or rapidly intensify.

Just my .02. Saying that I wouldn't be suprised if "fred" fell apart or became a Cat 3 Hurricane - just the same.

so according to this its been moving at about 260 degrees since moving off the coast right?

Quoting StormW:


It's the same principal as just sinking air, like from the MJO downward motion. As air sinks, it warms at the DAR of 5.5F/1,000ft. As the sinking air warms, it has the tendency to dry out the atmosphere.

Dry Adiabatic Lapse Rate right?

Quoting VAbeachhurricanes:


so according to this its been moving at about 260 degrees since moving off the coast right?

yea, due the Azores side the subtropical ridge

Almost the peak of the season and we have one depression and two tropical waves to watch!

Fred BUST

Just ignore SyKid, just a wishcaster who is upset that a Hurricane isn't coming to his house so he'll downcast the season. I'm sure if a hurricane threatens the US he'll be all 'Category 5 shortly'.

One thing I've learn is that Tropical Forecasting is very difficult becuz you are trying to forecast the state of an atmosphere that is uniform in structure or composition throughout. As compared to mid-latitude weather where the atmosphere is contrasting.

Quoting Weather456:
One thing I've learn is that Tropical Forecasting is very difficult becuz you are trying to forecast the state of an atmosphere that is uniform in structure or composition throughout. As compared to mid-latitude weather where the atmosphere is contrasting.

Very true.

Seems to me that TD7 continues to organize as far south as it possibly can.

Just for today, winds have shifted from the west to SSE with buoy 13001 located south of the cape Verde islands.

Since buoy 13001 is located at roughly 11.8 N 23.0W, I'm thinking the center of TD7 and soon to be Fred will organize between 11 and 11.5 degrees North.

Link

Hey 456, is there any chance for subtropical development for the NC low or if anything were to develop, would it be tropical.

hi StormW
can you please tell me what is gonna happen in GOM?? Thanks!!

TD 7 just dipped south

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT MON SEP 7 2009

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


A NON-TROPICAL AREA OF LOW PRESSURE ASSOCIATED WITH A MID- TO
UPPER-LEVEL TROUGH IS LOCATED JUST EAST OF WILMINGTON NORTH
CAROLINA. WHILE THIS LOW IS PRODUCING SHOWER AND THUNDERSTORM
ACTIVITY...UPPER-LEVEL WINDS ARE EXPECTED TO REMAIN UNFAVORABLE FOR
TROPICAL CYCLONE FORMATION. THERE IS A LOW CHANCE...LESS THAN 30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS. THIS SYSTEM WILL PRODUCE LOCALLY HEAVY RAINFALL AND
GUSTY WINDS ALONG THE COAST OF SOUTHERN AND CENTRAL NORTH CAROLINA
TONIGHT AS IT MOVES SLOWLY NORTH-NORTHEASTWARD. ADDITIONAL
INFORMATION ON THIS SYSTEM CAN BE FOUND IN PRODUCTS ISSUED BY
LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICES.

Gulf of Mexico

Quoting btwntx08:

u just made urself into an empty space goodbye # 40

What took you so long :)

good evening everyone

Im still new at this but is there still a chance of Erika reforming?

Hello StormW-

Did you notice 24N94W ?

Quoting cyclonekid:
Hey 456, is there any chance for subtropical development for the NC low or if anything were to develop, would it be tropical.

it dont think so. Its actually a shallow warm-core system but it does not appear to be a true hybrid system and most of the models take it to a cold core system as slides N.