Forecast model guidance remains in strong agreement in an anomalous evolution and structure of the 500mb pattern moving through the week of April characterized by strong ridging building into the Pacific-Northwest region during the early part of the week and shifting into the Inter-mountain West region along with significant trough amplification within the Northeast as the ridging within the Inter-mountain West continues building northeast into the Arctic domain, it will connect with the ridging within the Arctic domain, characterizing a highly negative Arctic Oscillation and North Atlantic Oscillation. This enhances the amplification of the trough across the Northeast:
12z March 30, 2024 run of the GEFS valid for 12z Tuesday:
12z March 30, 2024 run of the GEFS valid for 0z Thursday:
Highly anomalous weather patterns tend to produce anomalous weather and should this evolution verify, which is becoming increasingly likely, there will surely be some anomalous weather within New England. That anomalous weather would be in the form of accumulating snow and potential for significant accumulations. The period of interest is Wednesday, April 3 - Thursday, April 4, 2024.
Accumulating snow within New England during April can and does happen, however, climatologically speaking it is typically the higher terrain (generally above 1,000 feet in elevation), especially the farther north into New England one goes. In the case of this setup, these areas would stand the greatest potential for significant snowfall accumulations and winter storm impacts. However, given the anomalous nature of this setup, plus plenty of available low-level cold air, The 12z March 30, 2024 run of the GFS shows temperatures across New England at 925mb (~2,500 feet above ground level) just below freezing Wednesday morning:
Now it is important to understand where we are in the calendar. We are moving into the first week of April, average temperatures are much warmer than they are in the previous few months. In fact, during early April the average high temperature across many of the climatological stations is pushing into the 50's. So clearly, there has to be one heck of a cold anomaly in the lowest levels and a strong source of low-level cold advection to obtain temperatures cold enough to support snow for elevations below 1,000 feet and towards the coastal Plain.
There is another factor to consider with this system as well. The premise of this post focused on the 500mb pattern, however, we did not divulge into the surface. Associated with this anomalous 500mb pattern will be a low pressure system at the surface which slowly progresses eastwards across the mid-western states during the first few days of the week. There is potential for secondary low pressure develop and rapid strengthening. If this occurs, and where it occurs, will have great implications on the sensible within the region. Development and strengthening around or south of Long Island would result in colder low-level airmass to the coast and dynamic cooling could result in even colder temperatures down to the surface. This scenario would increase the potential for snow, even down to the coast and increase the potential for accumulating snow for elevations below 1,000 feet.
This is going to be a wild few days of storm tracking and this one has potential to yield some major surprises. As of now, the highest potential for a significant winter storm will be for elevations above 1,000 feet and within northern New England:
