There’s a lot going on today — and I could spend another hour typing up descriptions for the maps — so I’m going focus on headlines and publish ASAP

Top Story: Nor’easter — Blockbuster Blizzard — WATCH

A major storm is likely to develop out of the Southeast U.S. and emerge off the Mid-Atlantic and either head (1) East out to Sea or (2) snuggle up nicely off New England and pound the I-95 corridor into submission (with snow)

Current trends with AIFS and GFS —> major impacts, while the ECMWF IFS has been flip-flopping back and forth with 06z closer to the coast. This system is in the 5 to 6 day time frame, so predictability of the track should be pretty good into tomorrow — meaning we can either lock-in a blizzard or send it off to sea. I’m favoring the AIFS since it incorporates the model bias intrinsically when it generates new forecast simulations.

AIFS has 18” to 24” for every big city from D.C. to Philly to NYC and Boston. Clean sweep — grand slam “blockbuster blizzard”

And, GFS 12z just arrived as I’m updating this blog — 967 mb low pressure setting up shop just south of tip of southeast New England.

Impressive blizzard with hurricane force wind gusts …

California Storm System on Tuesday

Another major storm system crashing into California today with heavy coastal rain and mountain snows. The upper-level pattern has shifted colder out of the Gulf of Alaska, and, in the coming days = more unsettled, more snowfall … extending inland across the Great Basin and Rockies. Everyone seems happy here to resume winter in earnest — make up for lost ground from the past several weeks of extraordinary warmth.

Gusty Winds in the 40 mph with the rain bands — and much higher in the Sierra at hurricane force

CONUS Radar Simulation through early morning Thursday (7 AM ET)

• Western U.S. is hammered with rain and snow — another storm system on Wednesday into Thursday

• That warmer Pacific moisture heads east and northward into the Midwest and Great Lakes — setting up along a frontal boundary and developing a Clipper system or low pressure that keeps winter going for the Northern Tier

Temperature Anomaly Next 6-days

Another 4-5 days of mild weather and warmth east of the Rockies — until the cold pool up in Western Canada finally cuts loose and floods eastward behind the developing Nor’easter within a rather strong trough connected to the Polar Vortex.

Monster White Fuzzball (tropopause anomaly) over Arctic Canada on way to Greenland on Monday. More on this in coming days. A lobe extends southward into the Mid-Atlantic with a LOT of potential for rapid cyclogenesis (bomb cyclone development)

RTMA | Temperature Analysis | 11:00 AM ET

Avg Lower 48 temperature was 45.2°F

Temperature Anomaly | 11:00 AM ET

Lower 48 Temperature Anomaly above normal by 8.7°F

High Temperatures on Tuesday

High Temperature Anomaly on Tuesday

Temperatures in the 70s in Nebraska are > 36°F above normal. California well below normal with rain and snowfall

Low Temperatures on Wednesday

NWS NDFD Snowfall next 3-days

Clipper system extension of moisture into New England —> 2” for Boston

Arrowhead of Minnesota upwards of 2-feet of snowfall

Still another 7-feet of snowfall expected in the Sierra during next 3-days, and it’s not stopping anytime soon.

NWS NDFD Precipitation (QPF) next 3-days through Friday Morning

High Temperatures Next 8-days —> Colder air returns into next week

ECMWF 06z Precipitation Type + Intensity | Next 6-days

Moisture from the Pacific storm systems surge northward with the jet stream into Southern Canada — and fuels a “northern tier” boundary with Clipper Systems —> accumulating snow from the Dakotas into Great Lakes and Northeast from Tues-Thursday.

Eastern U.S. Next 6-days storm systems | ECMWF 06z

Nor’easter Watch Sunday-Monday!

Western U.S. Pattern Change —> Multiple Storms Pinwheeling Moisture

Sequence of storms until a break on Friday and Saturday before another HUGE circulation drops out of the Gulf of Alaska and spins more moisture onshore

Blend of Models | 10 Days Precipitation Total

Holy moly — huge precipitation totals for California — rain at coast + mountain snow

Blend of Models | Total Snowfall Next 10-Days

The Blend of Models is an ensemble mean of multiple different models and ensembles, so this New England snow signal seems exceptional — but with multiple Clipper systems and plenty of moisture, may be a good average estimate!

Snowfall in the Sierra, Cascades, and Rockies will be measured in feet / yards.

Flagship ECMWF 00z EPS | Temperature Anomaly | Next 15-days

A major surge of Arctic air returns for the Eastern U.S early next week — followed by another significant warm up — in the ensemble mean.

ECMWF IFS 06z | Precipitable Water Next 6-days

15-day Snowfall (Long Range) ECMWF AIFS 06z Cycle

ECMWF AIFS 06z developed the storm system with major coastal impacts (change from yesterday)

7-day snowfall totals would be astounding — can’t “lead pipe” cinch lock this quite yet, another 36-hours to get into the 4-day window

ECMWF AIFS-Single 06z | Temperature (500 hPa) Next 10-days

The temperature at 500 mb is the easiest way to highlight the “polar vortex” across North America with the coldest pool at -50°C (pink) with the -25°C contour usually associated with below freezing temperatures at 2-meters (surface).

Heading into the final week of February —> the main Polar Vortex cold pool reservoir remains largely locked up over Canada north of the Arctic Circle, but seeing multiple lobes descending in the Northwest and Northeast with surface low pressure systems.

Total Precipitation Median from Ensembles Next 15-days

Very little precipitation for Florida during the next 2-weeks — also Texas is mostly dry, and northward into the central plains

Ensemble Median next 15-days Total Snowfall (ECMWF EPS 00z)

Interquartile spread (75th % minus 25th %) shows variability in ensemble members

Snowfall is skewed toward heavier amounts — more extremes, so also need to look at probabilities, or individual point locations.

Probability of 1-inch of snowfall from the Ensembles (00z)

Probability of 6-inches of snowfall from the Ensembles (00z)

Temperature Anomaly | Next 15-days | ECMWF EPS 00z

5-Day Chunk #1 | Temperature Anomaly | Feb 17 - Feb 21

Well above normal for entire eastern U.S. but the Rockies and western Canada are cold

5-Day Chunk #2 | Temperature Anomaly | Feb 22 - Feb 26

Colder than normal just came into the Day 6-10 chunk with -7°F centered on Tallahassee.

5-Day Chunk #3 | Temperature Anomaly | Feb 27 - March 3

But, warmth returns for the beginning of March.

Maps sourced from weathermodels.com designed and innovated by yours truly! Please subscribe there for real-time access to the newest maps, charts from all of the weather models including ECMWF and AIFS, and NOAA GFS/GEFS.