Posts

Heavy rainfall possible in the East next week

A significant storm system is expected to evolve throughout a large majority of the United States over the next several days — with heavy rainfall impacts possible throughout the Eastern US by the middle part of next week. Much of this would come as good news to the drought-ridden areas of the Eastern US, but the uncertainties in regards to the storm systems exact evolution make forecasting the system extremely difficult. Intricate processes at work will determine exactly where and when the heavy rainfall occurs.

The storm system forms initially over the next 48 hours as a strong disturbance evolves into the Plains states. A strong low pressure system at the surface develops rapidly northward into the Dakotas. Precipitation will spread eastwards towards the Corn Belt by early Monday morning as a front boundary surges eastward. But this initial disturbance is not the only feature of interest. While significant aloft, a second disturbance will move through the Rocky Mountain range during the early part of the week, eventually interacting with the initial storm.

Read more

Premium: Active pattern to begin December, but uncertainties remain

The hemispheric pattern will continue to undergo changes as the month of December approaches, and this comes as no surprise to those who have been following our long range forecasts for the past few weeks. The main changes in the pattern are unfolding throughout the Pacific Ocean, where a large vortex in the Gulf of Alaska is being gradually replaced by a propensity for ridging. This causes a domino effect downstream towards the United States.

However, questions still remain in regards to the results of this change in terms of sensible weather. The source of cold air, speed of the pattern, and strength of individual storm systems are the main concerns; most stemming from the uncertainties in regards to the pattern in the higher latitudes from Canada towards the North Pole.

Read more

Pattern in transition as December quickly approaches

Over the past few weeks, much has been made in regards to a changing hemispheric pattern. Global circulations are in flux, and a much warmer than normal pattern has in fact changed across the Continental United States. However, the changes have been slightly less stout and slightly delayed when compared with initial ideas, and the atmospheric pattern has been left in an overall flux as we head towards December.

The Thanksgiving holiday is often an important time-frame in meteorology as one looks ahead to the upcoming winter. Gone are the days of wild speculation and assumption when it comes to the winter ahead. December is just a week away — and the ideas formulated regarding the pattern as we move into winters first month are beginning to obtain more weight. Some ideas are clearly losing steam, while others garner more attention.

Read more

The stratosphere, Pacific Jet, and a changing hemispheric pattern

A hemispheric pattern change is underway, and the effects will be felt throughout the United States quite quickly over the next few weeks. A dramatic change in wind speed and temperature in the stratosphere — near the very top of the Earth’s atmosphere — over the past few days, has re-shuffled the pattern throughout the troposphere — where most of our weather is observed. This is especially true in the higher elevations, nearer to the poles, where the stratospheric vortex typically resides. The disruption to the stratospheric vortex will have implications on the pattern throughout the Northern Hemisphere.

Here’s the thing: The stratospheric vortex is fickle. It extends from the troposphere to the stratosphere, so simply disrupting it or moving it won’t have dramatic implications. But what’s happened over the past few days, and what will occur through next week, is more than that — forecast models continue to indicate that the stratospheric vortex will be completely split throughout multiple levels. When the stratospheric vortex splits into two, dramatic implications can occur throughout the higher latitudes. Even if they don’t occur immediately, the splitting stratospheric vortex can lead to a domino effect which changes the pattern down the road.

Read more