3/06 AM All Zones: Warmer, Unsettled till Wednesday, Then More Cold & Snow Potential
Happy Monday! A moderating trend will begin over the next few days as mid-level ridging builds in from the west. Accordingly, the weather will also turn more unsettled, as a few frontal boundaries move through the region. Sunshine this morning will be followed by increasing clouds as warm-air advection begins to increase. Temperatures should still rise well into the 40s, with a light southerly flow today.
Mostly cloudy skies are expected throughout the Northeast states from tonight through Tuesday, as a warm front slowly moves through from southwest to northeast. Some spotty showers and drizzle could break out especially after midnight, as the low-level moisture increases from southeast winds overnight. Cloud cover will keep temperatures in the 30s overnight.
Despite mostly cloudy skies, a strong southwest flow will allow temperatures to rise well into the 50s on Tuesday. Showers are likely during the middle to latter part of the day as a cold front approaches. The best dynamics associated with the front will remain well to the northwest of the area — over Southeast Canada — so we don’t expect any particularly heavy rain. Behind this front will come much colder air. Downsloping winds will keep temperatures above normal Wednesday afternoon until cold-air advection increases later in the day.
NAM showing the cold front moving through period of rain or showers later Tuesday night
Later this week, a change in the large-scale pattern evolution over the Western Hemisphere, aided mostly by the development of significant high-latitude blocking, will support the return of wintry weather over the Northeast and Mid-Atlantic regions. Latest model and ensemble guidance suggest several waves could bring wintry precipitation into the region this weekend and into next week. There is still some uncertainty with the track and intensity of each of system, especially with the northern stream flow being fast and zonal initially.
The first opportunity will come Thursday night or Friday, The ECMWF, UKMET and GGEM model guidance keep this system suppressed to the south of the region. These models show the mentioned blocking to our north forcing the upper-level low to drop south into Upstate NY and New England. The low creates stronger confluence over Northeast, keeping the system more sheared and more moisture from coming northward from the Mid-Atlantic region.
The GFS model keeps the upper-level further north over Southeast Canada overall. So it allows system to track further north and produce more precipitation over the region. Lower heights ahead of this system, similar to the ECMWF, would likely mean more minimal impacts.
The ECMWF model forcing the first wave to track further south, with the more confluence form upper-level low over further south over Northeast
Of more interest, currently, is a second Pacific shortwave that could impact the region over the weekend. Latest guidance shows rising heights ahead of this wave as the upper-level low begins lifting out. Heights also begin to rise in the Rockies or Western Canada, behind the system as and upper-level low over British Columbia moves southwest into the Northeast Pacific Ocean. This trend, if it continues, will likely give this system more room for amplification and phasing with polar shortwave. High pressure with confluence to north will also support a cold air mass over the region.
As it stands today, models continue to show the system missing our area to the Southeast, while the blocking remains strong over Greenland/Davis Strait with an upper-level low just lifting out to our northeast. This illustrates the potential for the brunt of the system to move over the Mid-Atlantic. Again, the GFS models and it’s ensembles are further north with this system, because they are further north with upper-level low initially.
Other models, including the ECMWF, show late phasing with this system, and keep the track a little further south. The European ensembles, while aning towards a more southerly solution, do have some significantly impacting our area. This wave certainly seems like it is the “one to watch” moving forward.
0z/06 ECMWF showing the late phasing of polar and pacific shortwave energy, as more ridging develops over Northern Rockies and into Western Canada
Finally, later next week, more pacific shortwave energy digging may lead to another storm along the East coast. However, the blocking to our north may weaken by this point to allow for track further northwest or system to phase to late with northern stream off the coast. This may result more mixed or lighter precipitation in the region.
It should be noted that each individual threat discussed here still remains extremely uncertain. As the models begin to catch on to the pattern evolution, we may see more drastic changes with the upper-level features and evolution of individual system.
We believe the chances are pretty high for cold and snow threats with this pattern evolution — but that doesn’t mean anything is guaranteed. Stay tuned for further updates and details as we move closer.