Posts

Doug Simonian

Technical: Strong to Severe Thunderstorms Likely Late This Afternoon

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After some record warmth over the past few days, we are about to get our usual strong cold front “snap” back towards seasonable temperatures. But considering how warm and moist the atmosphere is initially, this means there will be quite an impressive temperature gradient, which is often a great fuel for storm development. Although the severe weather event in the Ohio Valley greatly underperformed (as expected), that does not necessarily portend an under-performer further east. While things do not necessarily lead to a major severe weather outbreak, the recent model guidance has actually trended a bit more impressive with a line of thunderstorms for late Saturday afternoon.

The reason this is happening is because there is a lot more backed low-level flow in our area compared to what the Ohio Valley had, meaning the surface winds are bending back to the southeast instead of the southwest. This adds more directional wind shear to the profile, considering winds just above the surface turn southwest — so that southeast to southwest turning with height provides some low-level rotation and thus a bit more organized updrafts. Additionally, there is a well-timed increase in the 850mb jet and lower just ahead of the strongest convection, allowing the line of thunderstorms to maintain its strength.

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John Homenuk

Analysis: Severe weather possible Tuesday

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An unusually organized area of low pressure, and an associated mid level disturbance, is expected to track through the Northeast states on Tuesday into early Wednesday morning. Riding on the periphery of a large mid and upper level ridge, this disturbance will gain extra energy along a thermal and height gradient which exists from the Great Lakes into the Northeast states. The low pressure center, at the surface, is expected to track from the Great Lakes into Central and Northern New England.

The track of the low pressure center will, at the surface, push a warm front northward through the Mid Atlantic states from late Monday Night into Tuesday morning. This warm front is likely to push through New Jersey to a position near Northeast New Jersey, New York City, and Long Island by daybreak on Tuesday.

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John Homenuk

Weekly Outlook: Heat continues, storms Tuesday

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While the ridiculous, oppressive heat of this weekend is in the past, above normal temperatures and heat will continue during the upcoming week. Heat Index values will again approach the middle to upper 90’s throughout the area on Monday and Tuesday afternoon. A low pressure system moving north of the area is likely to create some more unsettled weather on Tuesday, with the potential for strong and severe thunderstorms in parts of the area.

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John Homenuk

Strong and severe thunderstorms possible Saturday

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While lower dew points have been very well received in our area over the past several days, a warming trend will be underway once again by Friday. Increasing temperatures and moisture will become notable as winds, which had been coming inland off the area waters for the past few days, with to a warmer southwesterly direction. A transient ridge building overhead will aid in the warming temperatures moving into the Northeast US on both Friday and Saturday.

To our north, meanwhile, an expansive disturbance over Southeast Canada will begin shifting southeastward through parts of the Northeast US. While forecast models don’t currently show a strong or robust area of vorticity with this disturbance, the very broad disturbance has expansive height falls of its own. These act to supplement lift in the atmosphere along a cold front, which will be dropping southeastward through the Northeast states on Saturday.

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