May 20-23 MidAtl/NE Warm Temps

It's relatively short lasting but more summer-like heat and humidity is finally making a comeback, albeit a relatively brief one... widespread 80s are likely in the Mid Atlantic on Tues-Weds and for some on Thurs, likely reaching the 90s for some in the central Mid Atlantic on Tuesday and perhaps approaching 90 in NJ on Wednesday depending on cloud cover/shower coverage.

0z MOD modeled temperatures - generally 5-15 degrees above average, as well as overnight lows with almost everyone other than New England in the 60s for lows on Tues night.

Monday:



Tuesday:



Wednesday:

May 20-24 MidAtl/NE Severe Weather

Nothing from SPC on this yet although with a stalled frontal boundary, somewhat resembling the setup for the April 9-10 time frame, along with a more humid and unstable air mass, widespread thunderstorms should take place in the central-northern Mid Atlantic and the southern Northeast, especially on Tues-Thurs, with a risk of severe weather likely as well. There's plenty of instability, decent lapse rates although shear isn't too impressive. Tuesday appears to be the best day for severe wx in the northern Mid Atlantic and southern Northeast as by Wednesday, the back door cold front should be near or south of NYC.

12z CMC's take on the setup:

InstantWeatherMaps

The website has been having technical difficulties recently but seems to have gone entirely offline sometime in the last few days... hopefully it comes back on at some point, they have excellent maps IMO that are quick to load and with many parameters available for free. I especially like to use it during the winter months for major storms when the NCEP site is slower to load the model runs.

May 15-17 MidAtl/NE Severe Weather

Since I have nothing else to do right now... next chance for severe wx looks to be on Weds through Friday. Warm front on Wednesday moves through NY/PA into NJ, not sure about severe wx chances from that one but warm fronts sometimes overperform from what I've noticed in the past. Then cold front moves through sometime around Thu/Fri, location of severe weather depends on that as well as the placement of the warm front and how far NE it advances.

April 15-19 MidAtl/NE Warm Spell

Applying what went wrong and right with last week's outlook, I took the risk of opening another warm spell thread for next week with similarities and differences compared to this week. The main similarities include a widespread warm up in the eastern US, a cold front expected to move through parts of the region on Tuesday and Wednesday, and a more significant storm and cold front to push out the warmth on Friday. The differences include a lack of blocking over Canada and an upper level low to keep ridging suppressed, and an air mass not as warm as this week.

With last week's outlook, the ULL and surface high pressure in SE Canada were mishandled, with the GFS underestimating both and keeping the frontal boundary trapped north, while the ECM overestimated both, bringing the boundary into the central Mid Atlantic. In this case, assuming the large scale pattern plays out as currently expected, the lack of blocking and SE Canada ULL should allow for more northward expansion of the eastern US ridging, with the cold front on Tues-Weds moving through parts of the Northeast but likely somewhat north of this week's scenario, with the temperature gradient less extreme. The late week storm would also be able to track north of the current storm over the region, with the front possibly lifting back north on Friday. Of course, given the time of the year, something could go wrong and we end up with another widespread BDCF extending south of NYC, although the key highlight is that overall patterns favors at least a further north front and late week storm.

Note: The air mass in this time frame is not nearly as warm as this week, so while widespread 70s are expected in the Mid Atlantic, another case of widespread near record breaking 80s-low 90s weather for the central-northern Mid Atlantic is not very likely at this time.

18z GFS, FWIW: