Posts

Doug Simonian

Premium Weekly Outlook: Unseasonable warmth bookended by tastes of fall

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Another relatively calm and dry week looks to be in-store, as we’ll start off with a taste of fall, moderate to unseasonably warm temperatures, and then again experience a taste of fall. A cold front that moved through on Saturday night has completely cleared the area, giving way to a broad area of high pressure across the region. This has helped dropped humidity substantially, bringing us very comfortable temperatures — we started in the 50s in many locations —  as well as a lovely crisp morning. This high pressure will be in-control for today, with light winds, mostly sunny skies, and temperatures rising into the upper 70s to around 80. The weak wind flow may allow for some seabreezes to develop, but without a big difference in temperature between the land and ocean, these seabreezes should not be too strong, nor penetrate too far inland.

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John Homenuk

Long Range: Autumn cold blasts, southeast ridge

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Meteorological Autumn technically began 9 days ago now. Although Hermine took much of the focus off its start and placed it on tropical weather, the first 9 days of the meteorological season have offered an ironically similar pattern to what had been observed over the last month or so of summer. Warmer temperatures have dominated in the East — especially the Mid Atlantic. Much of this owes to a Southeastern US ridge, which has built back continually over the past 2 months, even when forecast models have suggested otherwise.

Meanwhile, back west, cold fronts and disturbances have continued to drop southward through the Northern Great Plains and into parts of the Great Lakes and Mississippi and Ohio Valleys. By and large, however, the colder than normal temperature anomalies associated with these disturbances have remained west of the Mississippi River. Airmass modification has essentially nullified any below normal temperature anomalies as they move east of there.

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John Homenuk

ENSO state in limbo as La Nina struggles

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Much fuss has been made over the past several months in regards to the development of La Nina this year, coming on the heels of one of the strongest El Nino’s on record. There is a propensity for these things to occur, after all, and a significant cooling of Nino-region pacific temperatures led many to believe that a La Nina was not only on its way — but could be moderate or strong by the time cold season arrived in the Northern Hemisphere. Those ideas will not come to fruition.

The lack of La Nina development has, instead, been notable — with a significant lack of depth to any cooler sea surface temperature anomalies. Trade winds aren’t cooperating (we’ll get into that more later) and tropical forcing seems to favor this pattern continuing through the next few months. It appears likely, now, that La Nina will never truly get off the ground. Forecast models have responded, with monthly and seasonal data now pointing to a Neutral (La Nada) pattern through at least the first half of North America’s calendar Winter.

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John Homenuk

Heat returns to East, but active pattern awaits

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The remnants of Hermine are still hanging around, off the coast of New Jersey and south of Long Island this afternoon. The system, in fact, has drifted farther south today than it has been all week — much to the ire of meteorologists and forecasters up and down the East Coast. Nevertheless, the storm will begin to have a lessening impact on our areas weather as the days of this week go on. The system is vertically stacked, at all levels of the atmosphere, meaning it’s cut off from moisture and lift sources.

Accordingly, the storm will fade out slowly over the next 24 to 48 hours, with only momentum carrying its circulation. As it does so, a large mid level ridge will build across the East Coast and Western Atlantic, as we have seen several times already this summer. This pattern looks to remain in place through the weekend, when temperatures will again approach the 90’s in many areas.

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