The Return of High Latitude Blocking and Coastal Storms…In May

A big -NAO block in Greenland, a deep 50/50 low, a large +PNA ridge on the West Coast, a deep trough in the East going neutrally tilted in the Mississippi Valley, lots of precipitation streaming up the coast from the Gulf into the area as a deep area of low pressure slowly moves up the coast…

Did we just go back in time to winter? Are we getting another blizzard? Well, not exactly, but the above description certainly sounds like a classic winter storm evolution for the Northeast. And perhaps if this storm were occurring a few months earlier, it would be a major winter storm. But alas, we are moving into May, and the above evolution may lead to a major rain event late next week.

The evolution towards a big blocking pattern is already taking place as the MJO moves towards phase 8. Of course, sometimes oscillations in spring do not have the same correlations as they do during the winter, but the MJO phase 8 in April in an ENSO neutral regime still correlates to a lot of high-latitude blocking. 

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4.27 PM Zones: Warmer air arrives late week

Cold and dreary weather had, for the most part, taken control of the areas weather over the past several days. Much of this can be blamed on the development of an upper level low over the Southeast United States last week. This upper level low drifted northeastwards towards the Mid Atlantic coast earlier this week, aiding in the development of a low pressure system which enhanced precipitation across much of the area.

The slow-moving cutoff low, which refers to systems that are detached from the overall jet stream, meandered in the region through this morning while slowly drifting off to the north and east. Residual moisture allowed for fog and drizzle to remain in the area. The good news is that, at long last, the system is departing and pleasant weather will finally return to the forecast.

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AM Zones Update: More Warmth Fri & Sat, Cooler Sunday, More Active Weather Next Week

Happy Thursday! An somewhat active or unsettled weather pattern through will continue overall over next couple weeks. There will be couple chances for isolated showers and thunderstorms, over next few days. But much warmer temperatures are still expected to end this week. No widespread rainfall is anticipated, until perhaps strong cold front and upper-level trough moves through early next week. We breakdown more forecast details below!

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PM Zones Update: Warmth Returns, but an Active Pattern Soon to Follow

Good afternoon, everyone! Clouds and showers have lingered across the area today as the cutoff low slowly drifts towards our area. Fortunately, the cutoff low is occluding and is thus weakening quickly, which means that the threat of rain will mostly be eradicated from here on in. But this was not before a general 1-2″ of rain fell across the region, including 1.46″ of rain at JFK and 1.25″ of rain in Central Park with some flooding reports in NE NJ.

With the cutoff low in such close proximity, the wind flow in the entire atmosphere has nearly come to a halt, as wind fields surrounding occluding cutoff lows (especially when it’s not winter) tends to be very slow. This slow wind flow combined with the onshore flow that ensues with the storm offshore will lead to low clouds, fog, and mist for the rest of the night as a marine layer remains entrenched. Fog may be somewhat dense in spots, but it may actually meet the dense criteria in E LI and coastal CT (visibilities below 1/4th of a mile). Temperatures will generally fall into the low 50s tonight.

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