pcray1231
Well-known member
Ah, yes. However.
http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html
This weekends festivities are northern jet dominated. Clipper type systems with no southern jet interaction. They're fairly strong, but they're clippers. They're gonna be moving pretty quick and are not moisture enhanced from the gulf or ocean. Not a ton of danger of a multiple inch type storm. Predictions are probably pretty accurate.
But....
Check out the 120 hr. That'd be Wednesday. Big old storm to our west. If this formed like this, it wouldn't miss us, and we'd be in for real rain on Thursday or Thursday night. This is the Canadian model.
The accuweather forecast is based on the GFS, which had this system (a very wet Thursday/Thursday night) up till yesterday. It did away with it today.
I haven't dug into it too deeply, but it looks like this is a phasing storm. In the animation, you can see the northern stream moisture starved clipper diving down out of Canada at hrs 45-80. It stalls over the great lakes. And then it gets "eaten" by the wet but weak southern stream storm in the west, strengthening it and drawing it up towards us. That would depict "real" rain.
Phasing systems are fickle. At a 6 or 7 day lead time models will lose, and re-find, that thing multiple times. It's all about timing. If the northern stream is a little quicker, or the southern one a little slower, they don't interact. That northern storm doesn't stall, and dies out as it slides north of us with not much more than some clouds. The southern storm stays south and weak and slow, and passes to our south a few days later, keeping clouds around. As the GFS now shows.
But if timing matches up they combine and bring a stronger, wetter storm right over our heads, and would be ushered out quicker too, bringing clearer skies (and higher streams) for the weekend to follow.
Bottom line: There's a rain threat Thursday into Friday. Threat, not certainty. It may or may not materialize. If it does, we get very wet Thursday and then it clears up. If it doesn't materialize, we don't get wet, and it stays cloudy all weekend.
http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html
This weekends festivities are northern jet dominated. Clipper type systems with no southern jet interaction. They're fairly strong, but they're clippers. They're gonna be moving pretty quick and are not moisture enhanced from the gulf or ocean. Not a ton of danger of a multiple inch type storm. Predictions are probably pretty accurate.
But....
Check out the 120 hr. That'd be Wednesday. Big old storm to our west. If this formed like this, it wouldn't miss us, and we'd be in for real rain on Thursday or Thursday night. This is the Canadian model.
The accuweather forecast is based on the GFS, which had this system (a very wet Thursday/Thursday night) up till yesterday. It did away with it today.
I haven't dug into it too deeply, but it looks like this is a phasing storm. In the animation, you can see the northern stream moisture starved clipper diving down out of Canada at hrs 45-80. It stalls over the great lakes. And then it gets "eaten" by the wet but weak southern stream storm in the west, strengthening it and drawing it up towards us. That would depict "real" rain.
Phasing systems are fickle. At a 6 or 7 day lead time models will lose, and re-find, that thing multiple times. It's all about timing. If the northern stream is a little quicker, or the southern one a little slower, they don't interact. That northern storm doesn't stall, and dies out as it slides north of us with not much more than some clouds. The southern storm stays south and weak and slow, and passes to our south a few days later, keeping clouds around. As the GFS now shows.
But if timing matches up they combine and bring a stronger, wetter storm right over our heads, and would be ushered out quicker too, bringing clearer skies (and higher streams) for the weekend to follow.
Bottom line: There's a rain threat Thursday into Friday. Threat, not certainty. It may or may not materialize. If it does, we get very wet Thursday and then it clears up. If it doesn't materialize, we don't get wet, and it stays cloudy all weekend.
int: 
