Tropical Development off of Florida

As should all of the high school games Friday night, but especially Yom Kippur services for the Yids out there (and that includes me).

 

I must live in a more tolerant part of the country. Due to Yom Kippur, all the Friday night/Saturday afternoon high school football games have been moved to Thursday afternoon. However I'm thankful I won't have to deal with that kind of weather going to and from synagogue.

 

The GOMex has pretty good hurricane-making conditions still, and no big storms recently to churn up colder waters from deep, so if there's a circulation when this thing crosses Florida, it could be a player.

Of the models shown on that page, the two (GFS/GFDL) aiming for New Orleans also have the center of circulation initialized farther south than it is, so that skews their projected paths. Which will hop all over the place in the coming days anyway.

 

Blame soccer for communism, but blaming it for the weather ... that's just bullshit.

 

I don't think being tolerant has anything to do with this. Other than Newman, most high schools around here are Catholic. I'm pretty sure from my Hebrew schooling days of yore that Catholics don't observe Yom Kippur. But man, that'd be awesome if they did. Make my weekend a little more manageable.

 

I blame The Andrew Meyer.

 

Newman!

 

Weather junkies:

September 19, 2007
this Wednesday morning
404 AM CDT

* * * Tropical Storm development looking likely to me in the Eastern Gulf of Mexico on Thursday; threatens the Northern Gulf coast states this Friday night through Sunday; WINDS will increase areawide later this week * * *

* * * Impacts on Southeast Louisiana & New Orleans a bit questionable at the moment, due to exact strength and eventual location, (as of early Wed. morning) * * *

Believe it or not, I've been keeping one eye open to this since this past weekend.

All of the forecasting dynamical models are unanimous that a surface low pressure area will remain well-defined as it crosses the Florida peninsula today and reaches into the the extreme Eastern Gulf of Mexico tonight, and then continues northwest thereafter into open Gulf waters. I'm a bit disappointed that projected intensities are not that bullish from 06Z output overnight. So, I'm a bit above that.

--- The summary on forecast tracks ---

Forecasting tracks overnight have now ranged from taking a tropical storm over a possible span area from as far west as the middle Texas coast to as far east as the Florida panhandle. This then places all of Louisiana in between those span of probabilities. There's been a tendancy to shift tracks further north from previous runs that used to take the area of weather into the Central Gulf from 2 days ago. The idea is now to trek it across the North-Central Gulf or even Northern Gulf of Mexico which now places a greater part of the threat area emphasis on Louisiana. The forecast runs overnight simulate that of a 1947 September 18 - September 20th track. Go look at the 1947 hurricane between September 18 - September 20. Remarkable, huh? And look at what today's date is. Pretty close, yes? But only this one remains to be seen if it can spin up to a hurricane. A lot of guidance projections keep it at only a tropical storm.

Should the tracks converge on Southeast Louisiana, the estimate on TIMING is between late Friday night into Saturday morning. At that same time, projected forecast intensities go from a range of a medium-grade tropical storm up to a Category 1 hurricane.

I wanted to interject that your Hwrf, showed a very large circulation on its nested grid from Tuesday night's simulation when it reaches the coastline. (What's Hwrf?) It is going to be the new-age takeover of the current Gfdl in a few years.

--- Some impacts on Southeast Louisiana ---

For our friends who still are south near the outer banks, marshes, and coastline, I expect you'll be receiving swells in the nearshore waters, and at the coastline will have a gradual water-rise into channels, bays, bayous, and other waterways at the end of this week. In the event that the circulation does become large as Hwrf insists then beach erosion or coastal erosion will take place, regardless of the track. These are the minor impacts. We'll hold off on word about any major impacts, until it becomes more certain where this should-be tropical storm's track becomes. But right now is a prime time to go over your small kit of supplies that you should have already gathered for this year's hurricane season. It doesn't appear as though there will be enough time for this entity to become anything like a major monster, as it'll have just 2 1/2 days over water, assuming a SE LA hit; 3 - 4 days for points westward, as in the northwest Gulf. I think these vortex models are too fast in scooting it across the Gulf, but plan for the quickest landfall, NOT the slowest.

--- Steering influences ---

An elongated upper ridge extending from the midwest U.S. southwestward to South Texas, will lay out ahead (Northwest) of what should develop into Tropical Storm "Jerry". An inverted upper trough will extend northeast from the Eastern Gulf (Jerry) up to the mid-Atlantic states on Thursday morning. A bit of north shear early in its journey, say on Thursday, looks like it should wane or subside on Friday. The upper low circulation extends clear up high into the highest altitudes of the troposphere, with absence of an opposing anti-cyclone at 250 to 200 mb up.

Okay, now what looks to be happening to me in the steering is that since there is this upper trough extension to the northeast of what should be Trop Storm Jerry, this upper trough extension exteding into the Carolinas puts a split in the ridge to the northwest over the Midwest States and the other Western Atlantic ridge. So, what I think is an opportunity here is for "Jerry" to take a bit of a northward movement on either Thursday or Thursday night, since it's being blocked to the west and blocked to the east. There is some blockage to the northwest of it at first, but the ridge to the northwest of it "lifts" northward with time, allowing for some northwest movement later.

What I'm trying to look for is a "closing-up" of the the trough over the Carolina's on Friday. The ridge from Oklahoma to Tennessee is trying to build eastward to "Join-up" with the Atlantic ridge and cause the trough extending northeast from "Jerry" into the Carolinas to recede. But to me, it doesn't seem to quite get the job done, and there's like a 'col', or just "gray matter", if you will between Thursday and Friday. The steering current can collapse anytime, it seems on Thursday night or Friday. If it just sits stationary, that would be a good thing for Southeast Louisiana, provided it doesn't happen north of 27 degrees north. An early northward movement, as what could happen on Thursday, into the Northeast Gulf by Friday makes it harder to avoid Jerry.

After seeing these developments on Friday, I can't lend much support for westward movement on Friday. I see more of a north or north-northwest movement instead. It's not going to surprise me if I see the threat increase over the northeast Gulf of Mexico instead. That's why I wanted to place the words of Florida panhandle in it along with Louisiana. This pattern, to me, favors more of the northeast quarter of the Gulf of Mexico. But finally on Saturday, if it's still around, it HAS to push westbound.

Contrast that kind of steering with the ECMWF which puts more emphasis on ridging over in the Eastern part of the U.S. as in Kentucky over to the Western Carolinas where GFS insisted a trough would be at. The result from the ECMWF?? Well, it's a Western motion since a high pressure ridge is directly north of it; then it propels it much more westward, and actually not allowing much northward movement.

So what happens when you take a blend of these 2 models?? Then you get Louisiana, right? Actually, GFS I think is a bit too hog wild on the westward motion in its surface reflection, as its upper steering doesn't support as much westward motion.

But, ECMWF has had its share of bobbing around with one run into South-Central Louisiana 2 days ago, then followed by a run into South Texas, and then followed by one of the last runs taking it into Beaumont, Port Arthur.

I've seen some hints of what's called "stair-stepping'. This means the disturbed weather goes west across Florida, then north over the Eastern Gulf, then west again over the weekend, and north. Well, you get the idea.

These situations are such a terrible pain and a thorn in my side. How far north before shifting west? Appreciably far north as in 28.5 to 29 degrees north with a large circulation will give squalls to Southeast Louisiana.

T. Scott Barry
Meteorologist
pvamagic@earthlink.net

 

When Nash Roberts tell me to worry, I'll start to worry.

 

Ah, Nash. I've heard much about this guy. Nothing but good things. He apparently eschewed the Super Duper Doppler 1 Billion for a dry erase board and common sense.

 

Which brings up an interesting philosophical question: If the guy's bucking all the "gimmicks," doesn't his simplistic approach become a gimmick in and of itself?

**Puffs, passes to the left**

 

Weather junkies know the only time you need to worry is if you see Jim Cantori in your town