John Homenuk

Aleutian ridge, cross polar flow will lead to more wintry pattern

/by

A pattern change discussed for several weeks is already underway, and will kick into high gear over the next several days. A much discussed ridge over Alaska will build northward later this week towards the North Pole. We call this a “poleward reaching” ridge — effectively named — as it develops towards the Arctic and polar regions from the North Pacific and Alaska. This is important for several reasons; but mainly because it helps to dislodge cold air which is typically bottled up in the arctic regions.

The ridge north of Alaska will continue to build this weekend into early next week — a very anomalous feature, even globally — and cold air will surge southward on its east end into the West and Central United States. This very same cold will eventually seep eastwards towards the Ohio Valley and East Coast. It won’t come all at once, in fact it likely will be in multiple rounds, but the cold will be anomalous.

Read more

John Homenuk

Another complex storm system possible next week

/1 Comment/by

On the heels of a large, complex storm system which impacted a large portion of the United States over the past several days, forecast models have continued to hint at the development of another system in 5 to 7 days time. Instead of being just long range model fodder, the hemispheric pattern progression suggests that this storm threat has some legitimacy, with the potential for a moderate to high precipitation event across the Eastern United States once again during the middle part of next week.

Much of the storm threat stems from the development of a cut-off low, or a trough and low pressure system cut-off from the jet stream, in the Southwestern United States later this week and weekend. This cut-off low looks likely to meander in that area for a period of time before ejecting east/northeastwards. The orientation of the upper level jet stream and height pattern suggests that the storm will eject from the Texarkana area towards the Mississippi and Ohio River Valley’s by the early and middle part of next week.

Read more

John Homenuk

More heavy rain expected in the Northeast on Wednesday

/by

A complex storm system will continue its evolution throughout the United States from later Tuesday into Wednesday. The first round shifted northeast of the Mid Atlantic this evening, moving towards Southern New England. A strong low level jet associated with this system aided in the development of widespread heavy rain, with many areas receiving well over 1″ of rainfall by the time the system ended.

Another disturbance, embedded within the same storm system, will approach the Northeast US on Wednesday. Ahead of its arrival, southwest winds will commence and warm, moist air will push northeast late Tuesday Night into Wednesday ahead of a warm front. This will allow some areas of dense fog to develop during the overnight period and into the morning hours of Wednesday.

Read more

Miguel Pierre

The importance of a cross polar flow and Aleutian ridge in December

/by

Multiple ensemble guidance indicate a major pattern change over the Pacific region. A ridge will builds near Aleutians then poleward into the Bering Strait and the Artic Ocean next week. This will cause cross-polar flow to finally setup over the North America.  All the anomalous cold air that is has been over much of Eurasia for the last several weeks with finally see an open gateway into North America. Temperatures departures are forecast to between 10 to 20 below average over parts of the Rockies and Northern and Central Plains over next weeks.

Read more