Thursday, February 5, 2015

Weather It Is (Historic Storm?)

Good Evening:

Is this going to be an historic storm?  Some would say that yes it will be.

Others will say we still don't know (or even no).

I would also like to add that there is a 25% chance that the word historic might just apply to the entire storm, which could intensify the following Shabbat and Sunday and turn even colder than next week's storm.

Winds will blow strongly on Monday and will likely even blow at storm force values on Tuesday with sustained strong gale winds (> 70 km/h).

Total precipitation amounts will exceed more than 100 millilitres in many locations, with some proportion of this snow (at higher elevations).

Snow becomes more likely on Wednesday, and could continue periodically in the higher elevations of the center for several days.

If the worse case scenario verifies, snow may fall even at heights of two to four hundred meters.

Combined wind, rain, and snow will make for dangerous and hazardorous conditions, from flooding, possible snow accumulation, strong winds, and possibly white out conditions in snow and strong winds. Dangerous conditions will prevail across the country. There will also be dust blown in ahead of the storm.

Yet, for all that might be -- the worse case scenario, we're still not sure.  We know it will be cold, very windy, and very wet -- but snow forecasts must be tempered until the upper air wave pattern becomes better resolved by the ensemble models, and we enter the period of our high resolution forecasts (within three days of the start of the storm).

We'll use these high resolution forecasts to better "see" just how the various factors that determine snow accumulation amounts come into play.  These can be, for example, temperatures in the layer of the atmosphere just above that at which condensation and collisions produce fast growing rain drops that can freeze into snowflakes, as well as rate of precipitation, and surface temperatures (faster precipitation rate and colder surface temperatures will bring more snow accumulation..

For now, we're in a wait and see, but preparations should begin, and take into account that we're highly confident about the heavy precipitation amounts, thunder and lightning, as well as extremely high winds.

Barry Lynn

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