A series of low pressure areas, each with a warm front ahead of it and a cold front following, will move from northwestern Canada to the northern or central Plains, then over to the East between now and early next week. Places north of each storm's track will have an episode of accumulating snow with cold winds, whereas places south of each track will have little or no precipitation of any kind. On the north side, there will be some temperature variation, but for the most part it will quite cold. South of each track, there will be wild swings in temperature as mild air sweeps in as the storm approaches, then cold winds erase any hints of mildness once the storm goes by. In this video, the GFS sequence is shown.
This week, a fascinating conference on weather and climate is taking place at Boulder, Colo. Reports from the scene yesterday marveled at a presentation by Dr. Howard Bluestein, where stunning imagery from severe weather events revealed much more detail than is currently seen by most operational forecasters.
Another presentation included a look at a new scheme for depicting and describing the risk of severe weather. The previous scheme included slight, moderate and high. As long as you remembered that slight was to be thought of as comparative term (more slight than moderate, but more serious than a depiction of no risk), you could relate to it. On the radio, however, if you say the risk of something is slight, I think many people take it as meaning there is not much to worry about. However, slight actually was the first level of enhanced risk.
The new idea has five categories of risk. The lowest is called marginal, then the more familiar slight, followed by a new classification of "enhanced." Enhanced is between slight and moderate. When you see all the terms together, there is some logic to the progression. However, when taken by itself, the term "enhanced" could be confusing. On the radio, you might hear, "There is an enhanced risk of severe thunderstorms today." Will people remember there are two additional levels of enhancement called "moderate" and "high"? I cannot confirm that the new scheme is actually in effect, but that was my impression from seeing a tweet from the Boulder conference. These maps show the old and new schemes.
In response to heating at ground level and a weak cold front approaching from the west, showers and locally strong thunderstorms should develop across northern Ohio this afternoon.
... much greater interest is being generated on threats and rumors about tropical storms. It is worthwhile to read Dan Kottlowski's authoritative reports on this. Here is a copy of his map from this morning:
The tropical Atlantic shows signs of life in the storm development department. Dan Kottlowski's expert discussion suggests the third storm (which could be Hermine) of current concern is one that could head to the Bahamas, Florida, the Gulf or ???
A large high pressure area centered just south of Chicago will furnish a northwesterly of pleasantly cool and dry air to the eastern Great Lakes and all of the Northeast today into Tuesday.
As the trough moves through each locality, warm humid weather will be followed by showers and thunderstorms, then cooler an drier air will arrive
D actually makes up the largest part of this map and represents the large area that is sunny for the most part