Hurricane Katia!

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DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
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TROPICAL DEPRESSION TWELVE DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 PM AST MON AUG 29 2011

AT THE TIME OF THE SATELLITE FIXES AT 00Z...A LARGE CURVED
CONVECTIVE BAND WRAPPED ABOUT HALF WAY AROUND THE CIRCULATION...
WHICH RESULTED IN SATELLITE INTENSITY ESTIMATES OF T2.5/35 KT FROM
SAB AND T2.0/30 KT WITH A DATA-T NUMBER OF 2.5/35 KT FROM TAFB.
HOWEVER...SINCE THAT TIME THE CURVED BAND HAS DISSIPATED...AND THE
CONVECTIVE PATTERN HAS DEVOLVED INTO MORE OF A SHEAR PATTERN. A
SMALL BURST OF DEEP CONVECTION HAS DEVELOPED OVER AND JUST WEST OF
THE CENTER...BUT ONE THUNDERSTORM DOES NOT MAKE A TROPICAL STORM.
THEREFORE...THE INTENSITY IS BEING HELD AT 30 KT FOR THIS ADVISORY.

THE INITIAL MOTION IS NOW 290/13 KT BASED ON A BLEND OF VISIBLE AND
MICROWAVE SATELLITE FIXES. THE GLOBAL AND REGIONAL MODELS ARE IN
EXCELLENT AGREEMENT ON A GENERAL WEST-NORTHWESTWARD MOTION OVER THE
NEXT 5 DAYS...BUT THERE ARE SPEED DIFFERENCES IN THE MODELS. THE
GFDL...UKMET...CANADIAN AND ECMWF MOVE THE DEPRESSION THE
FASTEST...WHEREAS THE GFS...HWRF...AND NOGAPS ARE SLOWER.
HOWEVER...THE TREND IN THE MOST RECENT MODEL RUNS HAS BEEN TO
WEAKEN THE MID/UPPER-LEVEL LOW NEAR 30N55W AND LIFT IT OUT TO THE
NORTHEAST SOONER THAN IN PREVIOUS RUNS. THIS RESULTS IN LESS OF A
WEAKNESS IN THE SUBTROPICAL RIDGE...WHICH IS ALSO FORECAST TO
CHANGE ITS CURRENT NORTH-SOUTH CONFIGURATION TO AN EAST-WEST
ORIENTATION BY 72 HOURS.
THIS CHANGE IN THE STEERING FLOW SHOULD
KEEP THE CYCLONE MOVING ON A WEST-NORTHWESTWARD TRACK FOR THE
NEXT 4 DAYS...
AND THEN SLOW DOWN AND POSSIBLY TURN MORE WESTWARD
BY DAY 5
AS A NARROW RIDGE DEVELOPS TO THE NORTH AND WEST OF THE SYSTEM.
SINCE THE DEPRESSION IS BASICALLY ON TRACK
...THE NEW NHC FORECAST
IS JUST AN UPDATE AND EXTENSION OF THE PREVIOUS ADVISORY TRACK.

THE EROSION OF CONVECTIVE BANDING FEATURES HAS LIKELY BEEN DUE A
NARROW INTRUSION OF DRY AIR COMING IN THE FROM THE NORTHEAST.
HOWEVER...ALL AVAILABLE DIAGNOSTIC AND MODEL FORECAST DATA INDICATE
THAT THE CYCLONE IS SURROUNDED BY VERY MOIST MID-LEVEL AIR WITH
HUMIDITY VALUES OF 70 PERCENT OR HIGHER...WHICH SHOULD ALLOW FOR
DEEP CONVECTION TO RECOVER LATER TONIGHT AND FOR THE SYSTEM TO
REACH TROPICAL STORM STATUS WITHIN THE NEXT 6-12 HOURS. MODERATE
NORTHEASTERLY SHEAR IS ALSO FORECAST TO AFFECT THE CYCLONE FOR THE
NEXT 24 HOURS OR SO...WHICH SHOULD INHIBIT ANY RAPID DEVELOPMENT.
AFTER THAT...HOWEVER...THE SHEAR IS EXPECTED TO SHARPLY DECREASE...
AND AN UPPER-LEVEL ANTICYCLONE IS FORECAST TO DEVELOP OVER THE
SURFACE CIRCULATION. THIS IMPROVEMENT IN THE VENTILATION PROCESS
SHOULD ALLOW FOR THE CYCLONE TO AT LEAST STEADILY INTENSIFY AND
BECOME A HURRICANE IN 48-72 HOURS AS SUGGESTED BY THE SHIPS...
LGEM...HWRF...AND GFDL MODELS.
Not a hurricane yet! Not even named yet. I bolded the key things above - It's heading toward the continental US for the next 5 days, and will intensify into hurricane strength. Conditions are very favorable for a hurricane.
 

dmcowen674

No Lifer
Oct 13, 1999
54,889
47
91
www.alienbabeltech.com
Of course the models start showing a more west solution (as opposed to the storm recurving north before getting to the states). Keep in mind the models for Irene first showed her going into the Gulf of Mexico, then Miami, then SC, then NC, then curving north before the states, then back to NC, then to NC to Long Island.

So, basically, take any info you see in weather models with a grain of salt this far out.

Great resource for seeing what the weather models are up to. It's a discussion board where people post the latest models and discuss their thoughts. It can get kinda snippy at times, but there are smart people on there.

The models never deviated from +/- 30 miles from center of track.

I would say that is pretty darned accurate especially given the size of Irene.
 

dmcowen674

No Lifer
Oct 13, 1999
54,889
47
91
www.alienbabeltech.com
Not a hurricane yet! Not even named yet. I bolded the key things above - It's heading toward the continental US for the next 5 days, and will intensify into hurricane strength. Conditions are very favorable for a hurricane.

It's Katia now.

It still has to get by a large high that if I was sailing the trade winds I would be languishing out there now.
 

shocksyde

Diamond Member
Jun 16, 2001
5,539
0
0
The models never deviated from +/- 30 miles from center of track.

I would say that is pretty darned accurate especially given the size of Irene.

The average inaccuracy of hurricane models 5 days out is 250 miles. We're over 10 days out.

Don't open your yap unless you know what you're talking about.
 

bobdole369

Diamond Member
Dec 15, 2004
4,504
2
0
Slow WNW trek as a 2/3 that becomes steady state. She'll stay NE of the leewards, not affect T&C, and recurve sharply south of Bermuda. A true fish.
 

dmcowen674

No Lifer
Oct 13, 1999
54,889
47
91
www.alienbabeltech.com
The average inaccuracy of hurricane models 5 days out is 250 miles. We're over 10 days out.

Don't open your yap unless you know what you're talking about.

They just officially listed the track of Irene as within 10 miles deviation.

You are the one that has no idea what you are talking about.

http://news.yahoo.com/irene-forecasts-track-not-speed-wind-203721735.html

Irene forecasts on track; not up to speed on wind


Hurricane Irene was no mystery to forecasters. They knew where it was going. But what it would do when it got there was another matter.

Irene made landfall Saturday morning at Cape Lookout, N.C. — a bull's-eye in the field of weather forecasts. It hit where forecasters said it would and followed the track they had been warning about for days.

By Monday night, five days before Irene first hit the East Coast, the hurricane center figured the storm would come ashore around the North Carolina-South Carolina border. By Tuesday night, they predicted it would rake the coast. And on Friday morning — 24 hours before landfall — they had the storm's next day location to within 10 miles or so.

Twenty years ago, 24-hour forecasts were lucky if they got it right within 100 miles and the average 36-hour forecast within 146 miles.
 

Balt

Lifer
Mar 12, 2000
12,673
482
126
it's gonna hit nawlins.

my prediction remains unchanged

Well Katia is really just Katrina with a couple of letters missing....

But I still say it takes a sharp turn north at some point and misses everything in the continental US. Given how strong it's predicted to be, that is for the best.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
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She's officially a hurricane now. Not going to make landfall in the US though. At least, none of the reliable models show it.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
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Down to tropical storm - but expected to reintensify to a Cat 3 hurricane. The models are changing more frequently than I change my underwear. One minute, everything's steering north by the time it reaches Bermuda. An hour later, 1/3 of the models show a hit on the CONUS. Then half of them, and then it's back east again. Latest models are mixed; some showing landfall. And with Lee in the Gulf (presuming one of the other lows don't get named first), if it heads northward in through Louisiana and up toward NC, then it's going to create a low to the west of Katia, with a high to the east of Katia, pushing her right into the mid-atlantic states.


Stay tuned! If you live along the gulf coast or Atlantic coast, it's time to start biting your nails.
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
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hurricane, not a hurricane, hurricane, not a hurricane - this is the second time it dropped back to tropical storm strength, but is expected to regain strength at any time, and to strengthen further after a day or so. Still not expected to make landful, although NC will be shitting bricks for a little while, and Cape Cod is likely to see the outer bands (at least.)
 

DrPizza

Administrator Elite Member Goat Whisperer
Mar 5, 2001
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Back to being a hurricane again today. Rapid intensification from tropical storm back to a Cat 2 hurricane. Now, a bit of wind shear, but in about 48 hours, might hit Cat 3 (and major hurricane status.) All the forecasts still say it won't hit the US, but they're all followed by "but, you never know." - Lee is having a bit of a role in increasing the levels of uncertainty beyond 3 days out.
 

Jaskalas

Lifer
Jun 23, 2004
36,504
10,775
136
Back to being a hurricane again today. Rapid intensification from tropical storm back to a Cat 2 hurricane. Now, a bit of wind shear, but in about 48 hours, might hit Cat 3 (and major hurricane status.) All the forecasts still say it won't hit the US, but they're all followed by "but, you never know." - Lee is having a bit of a role in increasing the levels of uncertainty beyond 3 days out.

There are questions if the weather in the US is capable of pulling Katia closer.