Thursday, February 19, 2004

"Climb every mountain, ford every stream, follow every rainbow, 'till you find your dream."

- The Sound of Music

First, a review of how the weekend is shaping up.

1. The I-95 corridor is now under a CROACUS WATCH. That means in the next several days, especially tomorrow and Sunday, you may notice little flowers poking out of the ground. Some readers has written in to say their lilacs are trying to bud. Those of you who have been around longer than me know that when the flowers and trees try to bloom early, it can only mean one thing:

2. This weekend. Friday will be a another reasonably nice day, with some sunshine, and temps will hang in the 50's ini most areas. Saturday.... Rain. First in Pittsburgh, then Altoona, then Philly and Baltimore. Temps in the upper 50's again. Sunday clearing but still warm.

3. Early next week. Monday.. clear and still mild. Tuesday... markedly colder as upper level systems in Canada are arranging to bring an arctic high southeast.

4. Wednesday. Lots of things will be happening in lots of places for an extended period of time... the Plains, the Ohio Valley, the East Coast, the West Coast.


In earlier posts I talked about zonal flow. Well what I may not have mentioned is that a straight flow across the country actually helps breed east coast storms when there is lots of moisture involved. Why? Because even if the jet streams move straight across the country (from the west coast directly across to the east coast) over time, say a period of a week, it become a channel or funnel. All the cold air to the north (eastern Canada) and moisture to the south (Gulf Coast), have to been squeezed through this conduit the atmosphere has set up for itself. The big picture with all this is we are looking at another round of cold, stormy weather at least through the first 10 days of March. Storms also have the potential to be more potent this time of year, due to several factors:

- Pacific, Gulf and Atlantic are now warming up... providing more juice to a late February storm than a late January storm.
- Snowcover in Canada is approaching maximum... enhancing cold air.
- A huge upper level low pressure system (called a block) is moving west to a position over northern Ontario, helping to enhance the jet stream flow underneath it. In simpler terms, the counter-clockwise flow around this low shoves the cold air under it, and directly to the east coast.
- Because of the warming Atlantic, it begins to create... you guessed it, the classic Bermuda high. Not the kind that gives us heat waves, just it's early season little brother. But the high acts to funnel storms a little farther north as they approach the east coast. Proof of this is seen in all the recent storms. Although the last one went out to sea, it didn't move out east of Georgia or the Carolinas. It just grazed the Mid-Atlantic. If fact, almost none of the storms this winter ever just marched right out to sea by Georgia. They all had some sort of northern component.


This time, unlike the NO storm, the Atlantic high will be a little stronger, pushing any system moving east a little farther north. And this time, the Canadian high is going to be locked in place, unlike the NO storm, where it kept on moving out to sea. You throw into all this a huge load of moisture coming east from the Pacific due to our zonal flow, and look out. The only sticky issue is how far north all this is pushed by the Atlantic high. If not far enough then it's anothe Carolinas and Virginia blast... if far enough, then:

You may be climbing every mountain (of snow) fording every stream (of snowmelt), following every rainbow (of Skittles) and finding your dream of a ... FABULOUS FEBRUARY.

Twenty-five years ago today was one of the biggest surprise snowstorms of all time in the "corridor." Feb 19, 1979 : Baltimore.. 20" Philly.. 12"

So enjoy the next few days of rest, rain and rays. Cause after that, it's gonna get wild again.

Perhaps there'll be an early or mid morning update on Friday, but we will be traveling Fri night, so no post again until Saturday afternoon. Sunday morning I will come out with my preliminary call on the Wednesday storm situation. After that, I'll post 3 times daily until the storm passes... early AM, mid morning, late afternoon or early evening.

For our readers in the public schools... tomorrow will be the first normal Friday you've had since January 30.

No comments: