Doug Simonian

Tracking a Couple of Light Snow Events Next Week

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Winter is finally about to make a return to the Northeast, and given that we are nearing the peak climatology period for snow, this often comes with snow threats. Often times, though, in an initial pattern change, the pattern becomes cold and dry for a period. And while it’s certainly a possibility that we will be cold and dry for a while, there has been increasing evidence that we may be tracking 1, 2, or even 3 light snow events in the next week or so. It all starts with an amplified PNA ridge in the western half of the US that greatly interacts with a lot of disturbances in Canada. This forces these disturbances to interact with this ridge and slide down into the Central US and try to amplify in the Tennessee Valley and gain moisture in the process. This is how you can get a little clipper event to turn into something more substantial.

Initially, the flow is very compressed and elongated in the South and in the Atlantic. This will serve to prevent any phasing with STJ moisture and also try to send any low pressure that forms well out to sea. So the moisture development and getting a low pressure to pop close to the coast may be almost entirely dependent on the amplitude of the PNA ridge and the interaction of the shortwaves as they initially enter the US, which means moisture may be hard to come by.

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Miguel Pierre

1/26 PM Zone Update: Colder weather arrives this weekend

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After some showers this morning, skies cleared for more sunshine with temperatures in the 50s. It will be breezy this evening with drier westerly winds possibly gusting over 35 mph across parts of region this evening. This is due a tighter pressure gradient over the region. Colder air begins arriving later tonight as temperatures fall into the lower to middle 30s.

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John Homenuk

The importance of the Pacific Ocean in the U.S weather pattern

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Thousands of miles away, in the Northern Pacific Ocean, a large ridge is develops in the atmosphere. This, if only by human nature, seems like a relatively inauspicious development at first. But its presence will be disruptive. Disturbances over the Western Arctic will be dislodged southward into Canada, cold air will push into the Northern 1/3 of the USA. The amplitude of the wave pattern will change. And suddenly, a snowstorm will develop along the East Coast of the United States.

Yes, we’re speaking in the past tense here. This already occurred, just a few weeks ago, during the most impactful winter weather event so far this winter in the Eastern United States. The root cause of the storm system, in relation to the atmospheric pattern, can be traced back to the Pacific Ocean, where a large developing ridge near Alaska completely changed what was an otherwise stale weather pattern.

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John Homenuk

AM All Zones: Showers clearing for sunshine later today

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A weak atmospheric disturbance, moving towards the Northeast US from the Ohio Valley this morning, will continue to shift through the region as the morning goes on. Isolated to scattered showers have shifted through Pennsylvania, New Jersey, and New York and have become slightly more widespread this morning. Temperatures remain relatively mild as the system shifts through.

The showers will continue their northeast movement as the morning goes on. Drier air, visible on water vapor satellite imagery and local observations, will shift eastwards from Pennsylvania through the Northeast US later this morning as a frontal boundary moves eastwards. This will clear showers away from the region, with a drier atmosphere leading to more sunshine as the day goes on.

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