Weather TALK [forecasts, etc]

[emms1121]

Lugi na mga car wash dito sa La Union at Isabela.. mataas pa rin ilog.. i work in La Union at bahay ko nasa isabela..
Mahina naman na hangin pero ulan tuloy tuloy pa rin..

[Jun aka Pekto]

It would drive me nuts trying to forecast this storm's track.......AAARGH!

A lot of forecasters are working overtime on this one.

The only good thing about this forecast is the storm weakening because it'll be over land for so long. Some cooler air must be pushing south from China or there's too much shear aloft which will hinder any re-intensification. Looks like JTWC is keeping it a tropical depression at the end of the forecast period.

I'm sure they have far bigger worries up north towards Japan.


This is one of those tropical systems that will be reviewed over and over (horror stories) not because of its strength but because it was such a pain to forecast.

[kinyo]

so they missed the effect of that high pressure in china, which caused pepeng to back out a bit ... and now that high pressure is probably gone, with the pressure at the east maybe higher, they are now again forcasting the usual route, westbound?

from the looks of it, it looks like pepeng have the tendency to be attracted by melong, now in japan, so baka mag-northbound sya ... ah ewan, kaya nga ang tawag sa mga yan bagyo eh, pabago-bago isip!

[Jun aka Pekto]

so they missed the effect of that high pressure in china, which caused pepeng to back out a bit ... and now that high pressure is probably gone, with the pressure at the east maybe higher, they are now again forcasting the usual route, westbound?

from the looks of it, it looks like pepeng have the tendency to be attracted by melong, now in japan, so baka mag-northbound sya ... ah ewan, kaya nga ang tawag sa mga yan bagyo eh, pabago-bago isip!

I have my doubts it's simply a matter of Pepeng being attracted towards Melor.

What keeps a tropical system tracking westward is usually a strong (semi-permanent) High over the Pacific. The center of the High is way out there. But it has "ridges" or arms of high pressure extending hundreds to thousands of miles out. Highs in the Northern Hemisphere have a clockwise motion. So, if a ridge extends westward from a High east of the Philippines, a typhoon has to get around that ridge. Hence it moves westward. Once it rounds the corner (where the ridge ends), it then starts moving northeastward because of the Earth's rotation. The northwest quadrant of a High moves towards the northeast or if we're talking about where the wind is coming from, southwesterly. Same premise for the southwest monsoon.

[Jun aka Pekto]

If you notice, tracing a route around west of the High is very similar to the route taken by many typhoons. It starts moving westward then curving northwestward to northward to northeastward.

Pepeng isn't attracted to Melor in my view. If they came into close proximity, they'd tear each other apart since their flows oppose each other. If the ridge from the Pacific High weakened then Pepeng will follow the same track as Melor (but it's not because of attraction).

JTWC has Pepeng moving westward once more. That could be due to two things: 1. The ridge from the Pacific High re-established or 2. There's a High over eastern China that'll keep Pepeng from moving north.