ATL: KATIA - Post Tropical - Discussion

[meriland23]

http://raleighwx.americanwx.com/models/ ... SLoop.html

[hurricanefloyd5]

looks like it might miss florida and that makes me happy

[weathermom]

Could this be another Dennis/Floyd situation, except for the NE? Irene dumped tons of rain on the NE, now Lee is going to move through later in the week...then if Katia hits ontop of all of that, could you imagine what the flooding would be like?

Unfortunately I can imagine that all too well. It could make the 3 feet I got in the house with Irene look like a little puddle

[LeeNess87]

Good morning everyone! Don't know how much I've missed. Can someone tell me why the current ensemble model only has one path on it, I believe the GFS?

[Gustywind]

03/1145 UTC 19.6N 55.0W T3.5/4.0 KATIA

[Cranica]

What's up with the enormous arc down to her south? I don't think I've ever seen a tail like that, isolated and with no storm activity.

[gatorcane]

This thread has sure become quiet now that a recurve away the United States is looking likely.

I think I hear some crickets

BTW, you have to give the long-range GFS some credit as it was consistently calling for a recurve earlier this week with the track the other models are converging on now.

In my opinion, the ECMWF was rather inconsistent in the long-range (one run showed it heading due west towards the Bahamas, others showed a sharp recurve around 65W), so a win for the GFS it looks like.

[gatorcane]

If I were working on the code for the UKMET model, I would certainly look at figuring out why it overdoes ridges like it is doing. Looking at the GFS and ECMWF, it shows nothing like this at 120 hours.

Maybe its also because it is too conservative on intensity since a strong Katia would punch through the western periphery of the ridge like the GFS and ECMWF show?

00Z UKMET, 120 hours:


00Z GFS, 120 hours:


00Z ECMWF, 120 hours:

[cycloneye]

HURRICANE KATIA DISCUSSION NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122011
1100 AM AST SAT SEP 03 2011

SEVERAL MICROWAVE OVERPASSES FROM EARLIER THIS MORNING INDICATED
THAT KATIA IS TILTED...WITH A MID-LEVEL MICROWAVE EYE DISPLACED
ABOUT 20 N MI NORTH OF THE LOW-LEVEL CENTER. FINAL T-NUMBERS ARE
DOWN TO T3.5 FROM BOTH SAB AND TAFB...ALTHOUGH CI NUMBERS ARE STILL
HOLDING AT 4.0. UW-CIMSS ADT ESTIMATES HAVE BEEN DECREASING AND ARE
NOW T4.1. KATIA WILL BE KEPT AS A HURRICANE FOR NOW...BUT IF TRENDS
CONTINUE IT COULD ONCE AGAIN WEAKEN TO A TROPICAL STORM LATER
TODAY.

KATIA IS BEGINNING TO MOVE AROUND THE SOUTHWESTERN PERIPHERY OF A
MID-LEVEL HIGH LOCATED OVER THE CENTRAL ATLANTIC...AND TOWARDS A
DEEP-LAYER TROUGH OVER THE WESTERN ATLANTIC. WITH THE EXCEPTION OF
THE UKMET...WHICH IS DISREGARDED IN THIS FORECAST...THE MODELS ARE
IN GOOD AGREEMENT ON MAINTAINING A MOTION OF ABOUT 305 DEGREES AT 9
TO 10 KT FOR THE NEXT 48 HOURS. BEYOND 72 HOURS...THE TRACK
FORECAST BECOMES A LITTLE MORE COMPLEX AND PARTLY DEPENDS ON HOW
TROPICAL STORM LEE AND U.S. EAST COAST TROUGHING EVOLVE OVER THAT
TIME. AS AN EXAMPLE...THE ECMWF DEVELOPS A DEEP-LAYER CLOSED LOW
OVER THE OHIO VALLEY BY DAY 5 WHILE THE GFS HAS A SHARP TROUGH
ALMOST READY TO CLOSE OFF OVER NEW YORK AND PENNSYLVANIA. DESPITE
THESE DIFFERENCES...BOTH MODELS HAVE SHIFTED TO THE EAST...WITH THE
GFS BEING THE FASTEST DUE TO THE MORE PROGRESSIVE FLOW. THE NHC
TRACK FORECAST IS ALSO SHIFTED TO THE EAST YET STILL LIES TO THE
WEST OF THOSE USUALLY RELIABLE MODELS.

STRONG SOUTHERLY SHEAR IS AFFECTING KATIA AND IS LIKELY ALLOWING DRY
AIR TO ERODE THE DEEP CONVECTION ON THE SOUTHERN SIDE. THIS SHEAR
IS EXPECTED TO PERSIST FOR THE NEXT 24 HOURS OR SO...DURING WHICH
TIME NO STRENGTHENING IS INDICATED IN THE FORECAST. THEREAFTER...
THE SHIPS MODEL SHOWS THAT UPPER-LEVEL WINDS COULD BECOME MORE
CONDUCIVE FOR STRENGTHENING...BUT THIS WILL ALL DEPEND ON THE
LOCATION OF KATIA RELATIVE TO THE DEEP-LAYER TROUGH OR CLOSED LOW
OVER THE EASTERN UNITED STATES. THE NHC INTENSITY FORECAST WILL
CONTINUE TO INDICATE INTENSIFICATION BETWEEN DAYS 2 AND 4...AND IS
STILL ABOVE THE INTENSITY CONSENSUS AND STATISTICAL MODELS.

IT IS ADVISABLE NOT TO FOCUS ON SLIGHT FORECAST INTENSITY CHANGES
NEAR THE MAJOR HURRICANE THRESHOLD OF 100 KT SINCE THERE IS VERY
LITTLE DIFFERENCE BETWEEN A 95- AND 100-KT HURRICANE. BASED ON THE
CURRENT FORECAST AND RECENT NHC INTENSITY ERRORS...AT THIS TIME
THERE IS ROUGHLY A 50/50 CHANCE OF KATIA STILL BECOMING A MAJOR
HURRICANE DURING THE NEXT 5 DAYS.

FORECAST POSITIONS AND MAX WINDS

INIT 03/1500Z 19.6N 55.8W 65 KT 75 MPH
12H 04/0000Z 20.3N 57.0W 65 KT 75 MPH
24H 04/1200Z 21.3N 58.7W 65 KT 75 MPH
36H 05/0000Z 22.5N 60.4W 70 KT 80 MPH
48H 05/1200Z 23.7N 62.1W 75 KT 85 MPH
72H 06/1200Z 26.5N 65.0W 85 KT 100 MPH
96H 07/1200Z 29.5N 67.5W 95 KT 110 MPH
120H 08/1200Z 32.0N 69.5W 90 KT 105 MPH

$$
FORECASTER BERG

[Maritimer71]

I'm still keeping my eye on this one...

[cycloneye]

11 AM EDT track.



Saved image.

[cpdaman]

Ya for whatever reasons euro past 4.5 days is not good. Inside that it is king. Crickets it is greeaaatttt

[northjaxpro]

I'm still keeping my eye on this one...

As you should Maritimer. I still think Katia will get too close for comfort up where you are come next week. Keep watching for sure. As Irene showed us last week, the models can change.

[magnusson_r]

No matter what the track prediction (and right now it is not in line for Nova Scotia) we are very fortunate that hurricanes --in the vast majority of cases-- lose steam very very quickly upon entering our northern waters.

Juan in 2003 was a rare event indeed.

[Aric Dunn]

just got back... why is everyone so quiet.. ?

[StormGuy]

just got back... why is everyone so quiet.. ?

Recurve syndrome!

[Aric Dunn]

just got back... why is everyone so quiet.. ?

Recurve syndrome!

oh... well thats no fun... any recon going out ?

[jinftl]

History can sometimes be the best indicator of the future...there are some noteable exceptions, but the bulk of September storms of similar intensity in the vicinity of where Katia is now passed offshore the u.s.

[Jevo]

My kind of storm.. long tracker.. lots of discussion and no harm to come of it. I've rather enjoyed Katia.. I think 20+ fatalities is enough for a month.. Here's to fish watching for the rest of the season

Cheers!

[BigJ]

Will there be a significant storm surge or rip tide on the southern side of St Maarten or the east side (Oyster Bay)?

I guess I'll find out when I get there tomorrow but?