Tuesday 9:45 a.m.
Speculation swirls concerning how Sandy from the tropics, chilly air from central Canada and a blocking high pressure area developing in the North Atlantic will interact. So far the ECMWF model has been most threatening, although its track shifted by more than 200 miles yesterday. This video has more.
In the meantime...
Today is national mole day from 6:02 a.m. until 6:02 p.m. Why is it on this date and only at those strange times? And what's a mole anyway? Every substance has 6.02 X 10 to the 23rd power molecules in a mole of that substance. The number 6.02 times 10 to the 23rd is called Avogadro's number, named for Amadeus Avogadro, who must have had his name changed to cause trouble for all chemistry students who followed. This fact has allowed chemists to measure substances exactly in the laboratory. Since 6.02 is part of the number, it explains why the celebration of mole day runs from 6:02 a.m. until 6:02 p.m. And, since multiplier is 10 to the 23rd, Oct. 23, or 10/23 is the appropriate date.
The only other question is what any of this has to do with the weather, and quite simply, I cannot answer that. However, the chemistry of weather systems across the country during the next week or so will become quite volatile, partly because of thermodynamics. That volatility could mean thunderstorms where chilly air in the north mixes it up with warm, humid air in the south.
Today, we see that interaction between warm and chilly air masses along a boundary stretching from Illinois to New Jersey. In the I95 corridor, the day started with a mixture of clouds and sun, but elements of rain showers could compound your problems in planning your afternoon. Let me remind you that if a thunderstorm charges into your neighborhood, get the lead out and seek shelter. You may need to buffer yourself with a raincoat.
For a while, thick clouds will make it bleaker than a dirty beaker, and anybody who wants light to come into their houses should leave the curtains and valences open.
In areas outside the showery areas, it'll be fine for viewing the autumn scenery.
And, much of tomorrow and Thursday should be fine for being oxide with temperatures in the 60s in the north and 70s in the south.
Toward the end of the week, a southerly flow of warmer should affect the Ohio Valley then the Northeast. At the same time, colder flow coming into the western Great Lakes will make it go lower on the temperature scale. The northwest wind will be the main reducing agent.
Of course, cold weather isn't so radical. It does mean we will be getting out the windchill chart, one of those periodic tables we use during the cold season.
For now, that's our solution for the short term. Keep accuweather.com in mind whatever your plans. Maybe you're doing some bonding. It's whatever gives you a positive charge. For dinner, whether we go out or eat in, some of us will experiment. For that, of course, sliced ingredients and mixtures including lettuce, tomatoes, cucumbers, radishes, onions olives and avogadros number in the millions.
As we go toward the weekend, we'll be trying to iron out the details about the storm threat next week. It is more complicated than a simple either ore situation. It is potentially explosive, but we will work to explain everything until elements of uncertainty argon.
Avogadro go now!
There's a west to northwesterly flow of basically dry air from south-central Canada to the northern part of the Middle Atlantic states. The flow changes orientation farther south. A light northerly flow is helping slightly less humid air to seep southward.
In parts of the Northeast, a sky looking as blue and clear as the one in the picture will be quite a departure from the look of the rainy skies that were much more common earlier in the summer.
The steering winds aloft are changing, and the next phase looks like it will feature a northwesterly flow of cooler air this weekend and much of next week.
It's going to be hot hazy and humid in the much of the Northeast today through Thursday. The recalescent, sudorific, canicular, pyrogenic frying heat gains our attention.
A line of persistent showers and thunderstorms stretched from Long Island Sound to Cape Cod. Some areas in this zone had more than 3 inches of rain this morning, and there can be highway flooding in localized heavy showers this afternoon and evening. This radar shows the rain zone just after 10 a.m. ET.
This map shows the predicted upper-air flow for tomorrow night. Our timing estimates suggest showers and some thunderstorms could affect the I-95 corridor from Portland and Boston to New York City (and perhaps Philadelphia) on Sunday.