Well.......Weak Equals West?

[Scott_inVA]

Well,

Interesting update on the map. With the exception of the now nearly hapless hurricane models (mid-lat is not where one wants to rely this suite), the trend continues west.

What was Dover, then Norfolk, now Richmond could be Charlottesville or Harrisonburg, VA at the rate the models are going.

I am hard pressed to fight consensus trending, but I'm not sold on this...yet.

Up in Maine of all places, I learned the TC expression "weak means west". Certainly not an absolute, but the thinking behind it is often valid. I have found this to very often be true in the Carib and have posted a couple threads here opining the theory.

With Izzy, neg tilt certainly would help the scenario verify.

Check the map...then discuss

Scott
WREL Radio
Lexington, VA
http://www.wrel.com/hurricane.htm

[wxman57]

Scott, weak is a relative term. While weaker tropical systems generally move with the lower-level flow (generally east to west), I don't think I'd call a 949 mb hurricane weak by ANY means. This is one powerful major hurricane, not a tropical depression.

As for the model map, first you throw out the LBAR because it's a worthless model. Next you throw out the UKMET, because it seems clueless as to Isabel's current movement NW. Discout the BAMM because it won't do well with this type of a pattern.

What do you have? You have the most tightly-clustered models I've ever seen. All models are focused on eastern NC, near Hatteras. Isabel could go a bit east or west of the current track - it all may depend on how far north the first trof drags the storm.

Also, with a storm nearly paralleling a coast, like Isabel is, just a tiny left or right track shift can make a significant difference in landfall point.

[HurricaneQueen]

Scott:

I don't know enough to "discuss" negative tilt and weak equals west but your web site is getting more and more sophisticated. Wonderful info and a great job as always. Thanks and be safe, Lynn

[wxman57]

Scott:

I don't know enough to "discuss" negative tilt and weak equals west but your web site is getting more and more sophisticated. Wonderful info and a great job as always. Thanks and be safe, Lynn

Here's an example of a "negatively-tilted" trof:
http://home.houston.rr.com/wx/isabel51.gif

Note that the axis (red dashes) goes from northwest to southeast). That's opposite of a "normal" "positively-tilted" trof. The implications with a netative tilt would be that flow around the base of the trof would be heading to the northwest rather than to the northeast like with a positively-tilted trof. So a netatively-tilted trof may tend to drag Isabel northwest vs. northeast as it moves toward the coast. This COULD mean Isabel may head NW-NNW then turn NW near landfall, striking the coast at a sharper angle either north or south of the current track.

Again, negative-tilt or now, it'll all come down to how far north Isabel gets dragged north by the first trof. If it gets too far north, it may turn into the coast right into the Delmarva Peninsula. Or it could turn sooner and hit near Wilmington. That's why there is a cone of uncertainty on the forecasts.

[Scott_inVA]

Scott, weak is a relative term. While weaker tropical systems generally move with the lower-level flow (generally east to west), I don't think I'd call a 949 mb hurricane weak by ANY means. This is one powerful major hurricane, not a tropical depression.

As for the model map, first you throw out the LBAR because it's a worthless model. Next you throw out the UKMET, because it seems clueless as to Isabel's current movement NW. Discout the BAMM because it won't do well with this type of a pattern.

What do you have? You have the most tightly-clustered models I've ever seen. All models are focused on eastern NC, near Hatteras. Isabel could go a bit east or west of the current track - it all may depend on how far north the first trof drags the storm.

Also, with a storm nearly paralleling a coast, like Isabel is, just a tiny left or right track shift can make a significant difference in landfall point.

Near complete agreement from me. I use "weakening" as a general term when MSLP begins to rise. Certainly not intended to mean a weak hurricane; perhaps that deserves clarification.
A98 has been to Fl, NYC, LI, Bermuda and now is NE fishing before cutting into the Delmarva. Amusing.

LBAR...typically sucks the gas pipe.

BAMD, BAMM...again way past outliers.

Overall, tropicals are entertaining yet non illustrative of sensible climo.

UKMET on the map ATTM is 12Z (ingest problem so no 18Z) and is dead on TPC or within 50 miles, so that run is in the game...we'll see 0Z. So, yes, we see tightly clustered agreement. Agreement really developed today...don't know if everyone realizes how important and unique this is.

However, while remaining INVOF Cape Hatteras (which I've been on board with for a while), the downstream trend seems to be slightly to the west. Stewart's recent excellent discussion eluded to this possibility and it will be interesting to see if TPC nudges along.

Hope not, the PWG our wx station anemometer has recorded was a microburst 66MPH. Don't know how long it lasts in sustatined strong winds. :o

Scott