USCAPEWEATHERAF

We could seriously be trending towards a full phase potential between the southern stream and the arctic polar vortex by the time Jan 29th is here. We could also be dealing with four days strait or longer for snow.

I honestly still think the 29th system comes northwest last second. Short range are not as robust with the PV lobe in Ontario as the global models are and they show more amplification in the flow then the ICON, GFS and GEM models. The NAM 3km, 12km, RGEM, all like a more amplified slower southern stream system that emerges off the NC coast, while ICON is all the way in SC! There are three camps still, little to no interaction with the PV lobe, little interaction, and major interaction. We will have to see what happens if anything once the energy off the West Coast settles in the Desert Southwest. Once that is situated we will have a better idea as it will get the first shortwave out of the picture. Severe threat looks to have two pulses in the next seven days across the Deep South.

GFS and Ensemble mean are still trending correctly. Rest of the suite needs to start making adjustments at a quicker pace!

Remember with a powerful storm like the models are showing today, the region does not need a benchmark to ACK track for heavy amounts, the storm can be as far south as 75 miles of the benchmark.

Subtle Adjustments can bring us from the dog pound to the Great White Hurricane! **2:00 p.m. Eastern Standard Time Southern New England Weather Update** Simply put, the snow lovers across the region are at the mercy of the giant ridge over the Davis Straits and northern Canada territories. The -NAO regime with a large 50/50 eastern Labrador vortex is currently running the weather pattern across the Eastern US. It is dominating the weather scene. Dry and cold arctic conditions we feel today are from a dominant northern stream where north westerlies at H5 are driving our weather. The next few days will keep a cold and dry perhaps sunny regime over the region as clouds begin to infiltrate the South Coast of RI, CT and SE MA on Tuesday. Light snows should begin to break out across western CT and should be shunted to the south thereafter with little if any impacts to the rest of the region. This I can say with 60 percent confidence. The next stop is the 28/29th window in which a monster surface center will develop either off the Outer Banks of North Carolina, or the Delmarva peninsula. We lack any confidence at this time to make a definitive forecast of any kind, whether it would be snow, rain, sunny skies or cold cloudy days. We just have no confidence. Seven-to-ten-day forecast is simple at this moment, highs in the mid 30-s along the Cape and Islands, and everywhere else below freezing for the next week until next weekend when a cutter could present itself if the block breaks down. Again a lot of ifs and what’s until we get a better model consensus later down the road!

I compared both the H5 and surface MSLP maps from both Friday 12z and Today's 12z runs, what a huge change. Also I wanted to mention that the HI RES EURO model showed the surface low developing east of the Delmarva and then jutting southward. Could be a feedback with such an intense system.

Also, go back to the Friday 12z run instead and see the massive adjustment it made in 24 hours.

yes the entire mean has trended north over the last three cycles (23/-00z, 23/06z, and 23/12z cycles) The mean precipitation has increased too!

A bunch are north of the mean

Basically you have a consensus when confidence increases that an event will happen. This begins to occur as you get within four days of a single event time period. However, since the models are still at great disagreements at day 5 still with the handling of the Labrador (50/50 -NAO vortex) vortex and the Ontario (-AO) vortex and how they will interact with the 29th energetic shortwave trough, uncertainty for the 29th is still at great lengths. Right now, I am declaring the next 48 hours as a toss up to whether or not this system impacts SNE. The 26th system is dead for anyone east of the Connecticut River Valley, anyone east and south of the Pike is in the game for 2-4" still. Right now, we can just sit and wait for whatever the models trend towards the next two days! Oh and the energy for the 29th storm is still off the British Columbia west coast!

12z ICON is the most dramatic with the strong presence of the vortex over Maritimes. I am guessing since it is way off the reservation compared to the GFS, GEM and others, the ICON is the least likely solution and therefore a southern outlier with the UKMET, except that model came more northwest compared to the 00z run which was off Bermuda.

Our miracle comes with the models hopefully over estimating the short term strength of the confluence over the Maritimes and ahead of the shortwave trough as it reaches 75W longitude. Right now, the best bet for changes are the placement of the PV lobe over Ontario, potential phase and timing, as well as the confluence/vortex circulation over Labrador.

The biggest difference is not with the central southern Canada (Ontario Vortex) but the vortex east of Labrador. The vortex north of New Foundland crashes the growing ridging ahead of the main shortwave trough as it exits off the Mid Atlantic coast. The GFS and ensemble mean compared to the GEM show that the GFS suite is more amplified with the ridging over the Maritimes and NW Atlantic Ocean, while the GEM and the models that are less friendly crash the ridging and deamplify the shortwave trough therefore it enters the western Atlantic Ocean off of NC instead of the Delmarva.

Will, I noticed with the GFS runs that showed an impact from the 29th system showed a much stronger ridging presence between the PV lobe over central southern Canada, and the large vortex over the 50/50 location near Labrador. If the PV lobe stays west and does entrain some energy the surface low will track further west as it gets captured and intensifies with a sub 528dm upper level closed low. 850mb temps are extremely cold as modeled! With a hurricane force wind field as large as it is being depicted, there is a strong chance for at least a few bands of accumulating snows. The 12z UKMET did move more northwest this afternoon compared to the run last night!

I am guessing there is a large spread as well with the EURO ensemble individual members. I would like to see the next few days how the interaction with the PV lobe behaves in the guidance. Today's 12z runs have intensified the surface low into a sub 960mb low. Honestly, with a circulation as large as the models have it, there is a high chance someone east of the CT River Valley gets a few inches, maybe low end warning criteria snows.

How about a stronger Jan 15 system. The upside is huge for the 28/29th system, the problem is, how do we get to that solution? Right now, there are three options: 1.) PV lobe phases west and earlier like Ray said, 2.) a partial phase happens too late and a non event happens, 3.) no phase happens and we get a 12z GFS solution where the E Massachusetts coast gets a long NE fetch of cold arctic air producing OES!

Especially since the deformation bands seem to be further northwest then modeled in these large nor'easters. The 06z EURO seemed to push the vortex over Central Southern Canada towards Central Hudson Bay instead of towards eastern Ontario. That is a good sign and if the trend continues into the 12z runs, this is what we want to see.

06z GFS and its ensemble mean got better overnight, while the EURO was garbage and the UKMET was garbage. The biggest difference in the models is the lobe of PV vorticity/vortex that hangs around the GRT Lakes on the UKMET AND EURO guidance while the GFS and ensemble mean pushes the vortex to the north and has no impact. My best guess is lean the GFS and ensembles with this situation. I am guessing that the PV low does not phase with the storm.

This is the one with the best potential.

Just an interesting scenario.

Oh I am, I mean blizzard conditions but with a few inches of snow is on the table too

It is a new run, you need to watch the other guidance unfold and none of them are out far enough! Take it easy!

The 00z GFS and CMC already disagree with that random vortex north of the Great Lakes, the GFS does not have it that far south and the CMC is trying to get the vortex involved and shunt the storm out to sea!

The 29th system is the one we all want, not the crap system on the 26th. I would greatly sacrifice that 1-3" potential over a 976mb low at the benchmark potentially. Remember, we do not need a massive sub 970mb low at the benchmark for a widespread historic event, the Jan 05 blizzard and Jan 15 blizzards were both between 980 and 976mb as they approached the benchmark. Also the large circulation reminds me of the FEB 08, 2016 snow event, coastal blizzard!

Yeah Ray, maybe I meant the confluence streak north of Maine!