Tuesday, September 24, 2013

Euro Hints At Cutoff Low Impacting Us On Sunday

If we were to believe the Euro from several days ago, we would have been dealing with widespread rain around here today from a coastal low.

Instead? Lots of sun and a pretty nice day after a chilly start.

Well, the Euro computer model is at it again, hinting at another coastal storm for Sunday over its past two forecast runs. This coastal storm is spawned by energy that exits off of the Southeast coast Wednesday night and Thursday, develops into an area of low pressure that cuts off in the pattern and spins back towards the coast, impacting us on Sunday with showers and breezy conditions.

It does have agreement from the Canadian guidance as well, showing a similar cutoff coastal storm that spins towards the coast this weekend. The Canadian also was suggesting we'd get soaked today as well...and that failed pretty spectacularly.

The GFS, on the other hand, does have a much weaker coastal feature out there that spins slowly and tracks far to the east of us. This feature doesn't wrap up and intensify on the order of the Euro guidance, which results in a track that's a bit more south and east. This model was much, much more accurate in portraying today's weather several days back (i.e. it didn't have a coastal storm hitting us today!).

We're not totally discounting the slight chance that the Euro and Canadian are right but both models are suggesting the 50/50 low we talked about over Newfoundland a couple days ago is farther east and that a ridge of high pressure can nose in between the coastal energy and this low later this week, cutting off the potential coastal feature.  This farther east positioning of the 50/50 would allow for more space for the coastal to develop in the Atlantic without being subjected to shear and confluence from the 50/50. It's all semantics but it does explain the "why" behind the modeling thinking.

IF it even develops, it's Sunday's problem...which means several days to watch it.