Invest 98L in Western Atlantic

[Thunder44]

Satellite might suggest something, but adding surface obs tells the whole story. As you can see, pressures are lowest near the coast of S. Carolina, not near the disturbance. There's one ship with a 1012.5mb pressure that looks VERY suspect as it doesn't fit any other reports in that area. Ship pressures are notoriously bad, as they don't calibrate their barometers very often, sometimes. In any case, there's no evidence of an LLC in that blob of storms. Any LLC is associated with the remnant frontal boundary to the northwest.

I'm surprised they called this an invest, but it could be another test. Before anyone charges me with committing a federal crime by suggesting that the NHC doesn't REALLY think this is significant enough for an invest but they want to run more tests, just consider that such tests are good. They verify that everything works properly. Tests help protect the public. I'm not "accusing" them of doing anything bad. They're doing their job, working to protect the public. One clue is that the last discussion said absolutely nothing about this bob. Just keep in mind that they did make some major software changes in June with respect to the ingestion of model data (simplified description). The only way to really be sure that the software changes work well with real invest headers is to have an invest and test it. A test invest won't do, they need the real thing. So, it could be a test. No harm done, as these invests aren't broadcast to the public. You guys know about them because you're all hurricane nuts and you seek them out.

So if it's another test, that's good. It shows the NHC is preparing for the heart of the season and they want to make sure all is working properly. Better to find out the software upgrades don't work right now, when any threat is minimal, than later when a significant threat develops. Let's see what they say in the next outlook discussion. I suspect they'll mention the area but say development is unlikely.

I see what you are saying, but it's hard to believe that a "test" is the ONLY reason for issuing a invest. If that is that is the case, why didn't the label the system in GOM, or those waves out in the Atlantic invests for a test? I have to believe that NHC really has a general interest in this area for possible development. Of course, we won't know that for sure, until they make official statements on it in their TWO or TWDs.

[wjs3]

I was unimpressed with this on IR this morning when I took a quick look. Thunderstorms look less concentrated as you loop it, and I thought tops looked to be warming...haven't looked at anything else yet!

[windstorm99]

As i noted with the current trof of low pressure in place this mess is most likely shooting up straight north and out to sea.

[wxman57]

thank you Wxman57 good post

which way might this blob be drifting in the future if it exists more than a day?

I think the storms will be drawn northward into the weak frontal boundary to the west. May form a weak frontal low east of New England in 36-48 hours, as suggested by the Canadian model. But the ECMWF doesn't show anything, and the GFS develops a low center beneath the upper low to 98L's northeast and moves it out to sea. So the GFS really doesn't develop anything out of 98L either. Keep in mind that the intensity models which develop 98L are told that there is an LLC now, which there isn't. And they're being initialized with a pressure of 1012mb, which may not be accurate. That one ship with a 1012.5mb looks suspect. Other pressures in the area are 1015-1016mb. So, assumptions are being made by the model runs that probably aren't true. Take the intensity forecasts with a grain of salt.

[gatorcane]

I knew this system looked a bit suspicious a couple of days ago although it more than likely has fish written all over it.

[wxman57]

I see what you are saying, but it's hard to believe that a "test" is the ONLY reason for issuing a invest. If that is that is the case, why didn't the label the system in GOM, or those waves out in the Atlantic invests for a test? I have to believe that NHC really has a general interest in this area for possible development. Of course, we won't know that for sure, until they make official statements on it in their TWO or TWDs.

I hear what you're saying. Even though the NHC knows that these invests are not supposed to be general public knowledge, they realize that they "get out" to at least a small group of weather enthusiasts and the word may trickle to the media. So they would be careful to not call anything an invest that is any threat to land, just in case. That's why they wouldn't do this in the GoM. From what I understand, the software updates at the NHC could affect the way model data are ingested. To fully test it, a real invest is needed, with a real invest header. True, they could test on any thunderstorm complex (or even in clear air) out in the eastern Atlantic. Perhaps they just picked 96L and 98L because they were at least a slight risk of development but no threat to land. I don't know, I don't work there, I just was involved in the discussions about the software upgrade in June. Risky thing upgrading software during hurricane season, and I'm sure they'll feel better after some real-life tests that pose no threat to the public.

[cpdaman]

on visible it look like somewhere near 26 - 71/72 there is some definite turning

[Thunder44]

Floater 1 on the NHC site is on this area, labeled on 98L by SSD:

http://www.ssd.noaa.gov/goes/flt/t1/loop-vis.html

[windstorm99]

The real season starts in 2 weeks or so....

Pressures are high around the area 1010-1014mb.

[wjs3]

BTW, whether or not the NHC tasks recon on this will tell us a lot about whether it is an internal "test" or the real deal from where they sit.

WJS3

[wxman57]

on visible it look like somewhere near 26 - 71/72 there is some definite turning

I'm not seeing anything in the way of an LLC. I do see the blob moving NNE. There's an upper-level trof approaching 98L from the west, presently. This is likely enhancing the thunderstorms a bit. But soon that enhancement may turn to increasing wind shear. Just in the last hour it appears the storms may be diminishing.

Just remember that many of you saw a low forming in the Gulf a few days ago when there was high pressure at the surface and anticyclonic turning in the wind field. Satellite alone won't tell the whole story. I'll check in occasionally with a surface plot. Next full ship obs come in around 1520-1530Z.

[wxman57]

BTW, whether or not the NHC tasks recon on this will tell us a lot about whether it is an internal "test" or the real deal from where they sit.

WJS3

Good point, let's see what the next recon POD says and what the next outlook says. Really, I'm just looking at the facts and guessing what they're doing at the NHC. Predicting what the NHC is doing or what they'll do is harder than forecasting hurricanes. I told that to Chris Landsea at our AMS meeting in June.

[NONAME]

T-numbers

28/1145 UTC 25.9N 74.0W T1.0/1.0 98L

http://www.ssd.noaa.gov/PS/TROP/positions.html

[cpdaman]

wxman57 that UL trough (that may be enhancing t-storms) how far east is it forecast to progess

[Cyclone1]

98L? WHAT? Wow, I really didn't see that coming! It looks great!

[clfenwi]

ABNT20 KNHC 281459
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT SAT JUL 28 2007

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

AN AREA OF DISTURBED WEATHER HAS FORMED ABOUT 100 MILES EAST OF THE
CENTRAL BAHAMAS IN ASSOCIATION WITH A WEAK LOW PRESSURE SYSTEM.
THERE IS SOME POTENTIAL FOR DEVELOPMENT AS THE SYSTEM MOVES
NORTH-NORTHEASTWARD OVER THE NEXT DAY OR TWO.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER PASCH

[HURAKAN]

It has been a long time since we don't hear those magical words "potential for development." Lets see if we can squeeze Chantal out of this. By the way, they now confirm the weak LLC.

[Berwick Bay]

I think a key question is whether or not we really have a legit surface low down there. Now 57 has told us that lowest pressures are actually well north off South Carolina. Also, we see model guidance which assumes a surface low taking this north and east along the trough boundary. But what if there is not a clearly defined surface low (at least not yet). Would this system then have a chance to fester for a couple of days and perhaps allow the trough to "miss it"?? It started to look good yesterday and then disappeared overnight. Wondering if we might see that pattern again today, with it coming back again tomorrow. Any chance that an area of storms could be left to fester for a couple of days, then developing a surface low, after being missed by the trough? Doubt it, but just wondering.

[CrazyC83]

This came out of nowhere! It has some time to develop as well...

[wxman57]

Here's a 15Z surface plot with satellite. Doesn't look too impressive. Upper-level trof is approaching from the west, increasing wind shear across 98L. No evidence of any LLC or even a surface trof associated with 98L. Just straight SE-SSE winds through the storms.