Snow from alberta this Evening , what about the weekend?

Good afternoon everyone , hey what do you know!! , snow will fly for all of us this evening and tonight with a general coating-1″ with isolated 2″ possible. A very quick moving but robust disturbance has dropped in from NW canada , and is currently sweeping through western PA at this hour. This disturbance has a pretty good amount of PVA associated with it and will end up as a monster storm over the gulf of maine.

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There is growing support that some locations COULD receive some convective thundersnow as soundings suggest a moisture saturated atmosphere from 925mb to 600mb and a cold/dry air mass from about 550mb on up. here is an example of a sounding from NYC this evening.

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NE-US

This clipper not only will effect our weather tonight but will have a profound influence on the potential for the advertised weekend storm. As seen above this clipper will explode into a monster coastal storm and turn into a strong ULL that will act as a strong blocking mechanism in the North atlantic. By 0z tomorrow night , we get our ULL getting established over the canadian maritimes and we have a disturbance entering the west coast via the STJ.

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Say hello to the weekend storm!! , the orientation of this disturbance is absolute key as it enters in as a positive tilted TROF , and does not go into a negative tilt until it reaches about the mississippi river valley.

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The intensity of the clipper , hence the intensity of the ULL in the canadian maritimes as a result is keeping the polar & STJ disturbances from phasing to early into a – tilted short wave TROF east of the mississippi river valley which would be all rain for the region. What we have is a – tilted short wave TROF focused to the coast as well as PVA diving to the coastal waters at 12z saturday.

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This type of storm solution would be a wintry mix to snow for the interior like NE PA ,NW NJ, HUDSON RIVER VALLEY , into N CT , and a rain to mix to snow for the coast. The stronger ULL is in the canadian maritimes , the weaker the ULL near manitoba is and therefore the quicker the 925mb & 850mb low transfer to the coast and hence faster cold air transport. Way to early to be discussing storm totals and so on just realize the change in the models and more change likely coming , just to what degree is uncertain.

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