The NHEM SPV has been going through a rough start in part due to an Easterly QBO. A short-term acceleration is likely through this week, before warm activity flux begins to propagate into the Stratosphere as we near Thanksgiving. 1-2wks after, CFSV2, ECMWF-Ext, etc, show a decent pattern change.

Now that the month of October is over, we can finally assess what the Eurasian snow pack looks like. After a bold start, we've been steadily falling behind all other years in snow depth extent, on par with 24/25 being the 2nd least areal snow extent ever since records began in 05-06.

Cooler stormier times likely as we head into week 2 of November. ECMWF bullish on high lat blocking, but this is probably when the region see its first flakes fly.

From #Melissa's infancy to its peak intensity yesterday morning. Absolutely insane how we've been tracking this system for 20ish days.

17 days ago today, we started to see signs on AIFS-ENS guidance and FNV3 that we would have to watch a tropical wave that would soon enter the Caribbean to become #Melissa, which went on to become one of the strongest storms in the Atlantic basin and the strongest storm to hit Jamaica ever.

#Melissa recently reemerged off the coast of Cuba this morning and is moving through the Turks and Caicos at this hour. USAF has been in the storm investigating it, and we've seen #Melissa took a heavy hit through Jamaica and Cuba. Significant strengthening is not expected due to westerlies.

Oh no, what has happened to you, #Melissa? You ok?!

After a recent incident on the X account I will be temporarily moving my forecasts to Bsky. Welcome back everyone!

Well, the EPS weeklies grossly underestimated the strength of our SPV. This would make sense due to a persistent WQBO which favors a strong PV, would correct the models in time. A disruption is likely to start the new year before potentially strengthening again later into Mid January.

Latest snowfall map is out for tomorrow's nearby coastal system! Expecting a widespread 1-3" across the state of Massachusetts localized 4"+ just north and west of Boston. Enjoy the mood snow!

Pacific jet is about to rage starting this upcoming weekend with impacts being felt towards the end of Christmas week. Pacific jet is lacking sustained momentum/ unfavorable low frequency background so I'm expecting this to last a week or so before the pattern drastically flips colder and stormier.

Big arctic blast could threaten the nation's midsection and east coast this weekend. This will likely be our 'bang' until Jan 2025 meaning this cold shot will be going out with a bang. After this, Pacific marine air will cover most of the US providing warmth for the rest of 2024.

Cold shot predicted in late November verified accurately in the Ohio Valley, Carolinas, Tennessee. Prominent cool bias over the Plains down to Colorado, New Mexico and most of Texas.

Anyone outdoors just noticed a temp change? You're not alone! A cold front just came by!!

Our rainstorm is just getting started! Worth noting there’s cold temps out ahead of the storm. Some ice is possible. Stay safe out there early this morning. All ice will melt by mid afternoon when temps are expected to soar.

Looks like SPC has pulled the trigger on a very rare Slight Risk for southernmost portion of MA, most of RI and southeastern CT for locally damaging winds upwards of 60mph with a couple flashes of lightning possible. Please secure all loose outdoor items or bring them inside for the storm.

There will be some CAD going on from a current high pressure system in southeast Canada, as the storm rapidly intensifies to our west, it will force the high in SE Canada to lift away along with strong low level jet stream will cause temps to soar and winds will quickly follow after.

The trough will take another ~18hrs or so before it turns negative. This will enhance the storm's ability to rapidly intensify with heavy downpours and damaging winds upwards to 70mph+ on the coastline of MA, decreasing the more inland you go.

Our storm tomorrow is aided by this positive trough aimed at Texas, throughout the evening/night diurnal convection will increase in both frequency and intensity which will help release a lot of latent heat from our system to the downstream ridge. THIS will begin the storm's journey.

According to model analysis, tomorrow morning, Tuesday December 10th, 2024 will be the first day the Western Pacific Oscillation values turns positive since ~22.5 days ago!

Our Stratospheric Polar Vortex has peaked at its healthiest strength ~50 m/s last night! There's a potential for one more peak in strength next week before the SPV takes a beaten from strat warming in Siberia, western Russia and the UK.

People inside 95 have finally flipped over to snow for the first time of the 2024-25 winter season! Stay safe getting out the door tomorrow for school,work, etc. Some school districts have decided to delay start of school day. Listen to your local officials for school related info.

New unexpected snow map issued due to abrupt model trends which are cooler. Right now, I would think areas inside 495 and inside 95 have a chance for 2-3" but I am restricted by the boundaries of Winter Weather Advisory placements by the NWS. Enjoy the system, everyone!

Big time uncertainty on the 00z EPS for both the NAO and EPO teleconnection domain. It'll likely be a rough ride for models in the days ahead as we battle with persistent -EAMT,MJO promoting warmth. Low frequency forcing, warm SSTs south of Alaska supporting continued -EPO/+TNH pattern.

Here's my final snowfall map for tomorrow night into Thursday. While east of 495 likely gets mostly rain, I have included C-1" for the snow squall potential after the system passes on Thursday morning. Take it easy folks west of 495!

Our Stratospheric Polar Vortex is quite literally fulfilling life right now with no warm pulses being injected into the PV, however, this will likely change as it returns to a more normal state by mid December onwards.

For the first time in what feels like years, The ECMWF EPS showing a local station of mine, Lawrence, having 850s temps 0C or below for 15 days!! Of course this likely won't happen as warmups look likely day 10+. Cool to see though!

50mb U wind anoms this Nov so far (left) compared to NDJF 50mb U wind anom difference b/t -EPO & +EPO cool ENSO neutral & La Niña winters in JRA-3Q & ERA-5 since the 1940s (middle & right). This has been discussed for a while now, but when west QBO is coupled w/ cool ENSO, it favors -EPO in winter

A new parameter from ECMWF's upgraded cycle 49r1, is Thermofeel, aka, Thermal Stress. The plot below shows moderate to strong cold is expected for most of the central and eastern US with very strong cold being modeled in the northern Plains/Canada for Thursday December 5th. It's gonna be cold!!

Updated model consensus still looks a bit uncertain for Thursday but models agreement has gone to the ECMWF, after days of refuting it's output, my forecast has shifted towards the ECMWF, but still south, favoring KMA and southern models.

Another stretch of the 10hPa SPV is expected late this weekend into early next week which will likely aid in a arctic cold shot by week 2-3 of December, well before Christmas.

While most models agree on a general consensus for Friday, some of the track spread is wide enough to make a difference. UKMET/AI is south than most physics models meaning it is colder and less amped. Given record performances in AI, have decided to lean to it for now.

Welcome to 00z everyone!!

Significant arctic blast is set to invade the U.S. by Wednesday spreading eastward, arriving to the east coast by Friday. The mean trough will lock itself over the east coast with a mean ridge over the west. It is also looking dry throughout this period too. Bundle up everyone!

Significant weakening trend noted by the ECMWF SubSeasonal prediction system by Mid-late December, if true, it could make for an interesting start to 2025.

A storm threat on Friday that I'm watching. Currently most models remain off shore with this system while euro/EPS is the most amped. I expect euro to come down to other models and AI models over the coming days. Right now, I have best chance for plowable snow. NW of I-95. Will be watching trends.

Cold will open the flood gates as a -NAO, -AO, -EPO and -WPO sets shape. Teleconnection values will be strong in amplitude allowing the magnitude of the cold air to be strong. We maybe talking negatives for highs/lows in the northern plains with high temps 20s-30s for us and lows in the teens!

In my 8 years of doing weather as a hobby, I've never seen the WPO so negative and persistent. This is some insane stuff.

What a difference a year makes, phew...

Seeing the coldest pv lobe over our heads is favorable to propagate downwards to produce more cold over the Hudson Bay, this could enable the cold pattern ahead!

Drought monitor update now shows an EXTREME drought which encompasses 25% of the state..this map was made on Tuesday, well before today's storm.

Things have changed in 24 hrs for next week and beyond, after some big changes to the teleconnections, the US has trended much colder. The Pacific pattern and cold air could be the best we've seen in YEARS. Some snow may come with this pattern. Bundle up for Thanksgiving and beyond!

First time since I’ve seen this kind of agreement 10 days out! I am now watching this storm threat..

Coming Thursday into Friday and the weekend, New England will experience a nice dosing of rain, though not drought busting, it'll be appreciable at the least. Some backend snow is possible for higher elevated areas.

November has been really mild east of the Rockies and I expect that to continue through month's end..still a lot of uncertainty for when/if the pattern gets cooler, so far in typical fashion, it's been delayed from late this week to next weekend after Thanksgiving.

Many ECMWF subseasonal members are pointing to a very strong or record breaking PV beginning on Thanksgiving onward.. If the AO trends positive along with expected MJO propagation through phases 4-6, canonical La Niña style pattern would occur. I am expecting a good part of December to be warm.

My favorite image of the year goes to Starships successful landing in the Indian ocean a little while ago😍😍

ENSO update came today which shows a cool neutral equatorial Pacific. That along with other factors discussed in my winter outlook last night, leads me to conclude we will have a better winter than the last 2 winters.

Currently sits a rapidly intensifying powerful extratropical low in the northeast Pacific. Luckily we got a buoy on site that has been observing real-time conditions over there. Buoy #46005 currently is reading a 958mb mean sea level pressure with wind gust nearing 60kts.

Welcome to the first winter outlook here on BlueSky! First up, we have a cool neutral ENSO over the equatorial Pacific which typically supports ridge out west and a trough with colder air in the east..sadly, its not as straightforward as it may seem!