typhoon nalgae - Formosahut forum

Next one in the production line is rolling our way and we could be getting up to the last few chances so we better see if we can steer this one home. Looks a bit on the piddling size at this stage though it should ramp up in the next 24 hours or so. JTWC and CTB have it down as a so called 'straight runner' which would have it going south of Taiwan but i don't think the steering forces are as clear-cut as they were for nesat so there is still hope. If it rides the edge of the STR it will dip down to the south over night before heading back up towards us courtesy of the developing weakness in the ridge - or so the theory goes. [image]

My thoughts exactly with regards of the potential of the steering ridge to whip this thing back poleward. The weather chart checked just now is below, and it looks like Nalgae will not be such an easy one to call. It certainly doesn't look like a straight runner.

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As typhoon forecasters, 'wishful thinking' is probably not supposed to enter into it, and that might be clouding our judgement slightly. As it stands, we are the outliest 'outliers' out there. However, on the other hand, the experts are predicting it to follow an almost identical path to nesat, and i haven't seen too many follow exactly the same path within the space of a few days and there is still a chance that a weakness could form in the ridge above taiwan, though that does seem to have receded somewhat.
One problem that i have encountered with trying to use the pressure charts to make predictions is that there appears to be large discrepancies between different charts (the weakness that was on the CWB one was not evident on the JMA one), and even the same agency will have major differences from one chart to the next. How do they draw these things up anyway, do you know?

With regards to 'How do they draw these things up anyway, do you know?'

No, I have no idea. But as I was cooking dinner tonight I had an epiphany. Due to the rain of which we've already discussed in the hornet thread, we had to move our fire to the protected 'porch area'. (A few square feet with a roof.) As I was cooking, I couldn't help but notice how the smoke followed me. It was spot on. I move, smoke moves. I move back, smoke moves back. My movements were creating 'steering ridges', lows or highs or whatever. It was a micro environment that clearly demonstrated how air follows minor fluctuations in local pressure.

I just noticed that the CWB updated the forecast for Taitung, giving us a 100% chance of rain through tomorrow night. They don't put their asses on the line like that often. Wait, I stand corrected, they would often have a 0% chance of rain for Pingtung as we were getting horrendous downpours. But they don't often issue a 100% chance of rain for a 36 hour period.

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This morning i think they only had us at 80% chance. When it is actually pouring in real time, and there's this big area of red stuff on the radar coming this way, then you think you could go crazy and call that 100%. However, good to see that they have finally introduced a 'heavy rain advisory' button (and you are right, they kept issuing heavy rain alerts for pingdong and meanwhile it's still down as 0%. Don't know how that works.)

A general warning level alert would be good too. Is there one? I mean does the govt issue them? They don't seem to do any of that pansy evacuation stuff either.

If we did have a warning system, how many levels, and what level do you think we would be on now?

There was quite a lot of water on the road. The worst bits were caused by the run off from those little offshoot mountain roads that funnel rivers of water onto the main road. At the very least, I seriously hope they have locked the gates on the the mountain passes and told the tourist bus companies to take a break coz there will be landslides for sure.

Anyway, this could be a wild night. The rain does seem to crank up here at night for some reason.

A warning level would be good, but only if it's dependable. To the extent that it raises false alarm, it is counter productive. This is the problem these weather services have. It seems that the science of predicting weather is, well, more intuitive than quantitative. But it's also administrative. In Pingtung County, for example, there are many micro climates. Where we used to live, there was nearly a 90% chance of daily afternoon showers between July and October, by my observations. And yet the CWB would list Pingtung as having 0% chance of rain because, I believe, they lumped Pingtung into the Kaohsiung weather report. These were isolated yet daily events, and so in that sense the error was administrative.

Nalgae is different, obviously, being an isolated event in all respects, but the pattern developing is one that should raise alarm, or at least a warning of some sort. The two images below are from 6:30am Taiwan time today and from just now, 9:00pm. You can see how Nalgae was breaking up in the earlier one, and how the system that has been feeding us since has been stationary. Should the CWB have been able to predict this? I have no idea. But it looks like we're going to get at least another 100mm before it's over.

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