AM thoughts before 12Z guidance comes in- it is possible we never see guidance come into agreement on a uniform solution. Frankly, it is rare that happens anyway. The meteorology says a rapidly deepening mid-upper low off the coast favors areas along & east of I-95 especially...

Rare late day update to the Key Messages as new guidance continues to trickle in. Confidence is increasing in a highly impactful winter storm Sunday into Monday along the Northeast coast with disruptive snowfall as far inland as the western suburbs of I-95.

WPC has initiated Key Messages for this impending Nor'easter. While confidence in a storm system have increased, exact details on amounts & resulting impacts remain highly subjected to storm track. Continue to follow WPC's and your local WFO's forecast for the latest.

Spread in the past 5 EC-AIFS ENS runs has steadily decreased. But where there is lingering spread, it largely comes down to phasing & 500mb trough position & tilt. There is also lingering spread south of Nova Scotia, hinting at ongoing differences in wave separation & confluence.

An exceptional winter storm that has the Carolinas, eastern TN, and northeast GA in its sights will produce a swath of heavy snow, including potential blizzard conditions along the NC coast this weekend.

A major winter storm is set to produce heavy snow, whiteout conditions, and potentially blizzard conditions in parts of the southern Mid-Atlantic this weekend. Impacts stretch as far south as Atlanta & even Savannah. You can read the WPC discussion here: www.wpc.ncep.noaa.gov/discussions/...

The latest Key Messages continue to identify the Carolinas & Southesst VA as facing the worst impacts. Unlike the last winter storm, high winds & blowing snow are a bigger concern, especially along the coasts.

Good morning! Key Messages have begun for the eastern U.S. winter storm.

I left last week to the start of one winter storm, to coming back from my weekend off to another. I try to dive into some of the scenarios & why this weekend forecast is far from a lock: www.wpc.ncep.noaa.gov/discussions/...

Regarding the East Coast winter storm threat-- 06Z EC-AIFS ensembles still show high spread in a few areas: 1. The shortwave trough placement/amplitude/tilt as it track off the East Coast, 2. suppression feature south of Nova Scotia, 3. trailing shortwave in Central Plains.

Latest WPC post: "Here is the latest information regarding a potentially significant coastal storm this weekend. Chances have increased for impactful snow and/or wind along the immediate East Coast, but uncertainty remains rather high with respect to details. Be sure to keep checking for updates!"

12Z Dulles, VA sounding eqrlier this morning. Got family nearby that under 1 hour later were reporting sleet. The warm nose in the 700-750mb layer is the culprit.

"What does a classic freezing rain sounding look like?" Exhibit A--

Probably one of the busiest weeks of my career. A big thank you to everyone who collaborated with us this week. A thank you to all those who will be in their NWS offices working this event over the weekend. Lastly, thanks to our team at WPC for their hard work this week. Be safe everyone!

Here are the latest Key Messages from WPC which now sport total snow and ice accumulations forecasts.

My "Heavy Snow and Ice Discussion" for the impending winter storm just got posted: www.wpc.ncep.noaa.gov/discussions/...

Here's the updated Key Messages from this afternoon, now highlighting the potential for locally catastrophic ice accumulations. The snow and ice is going nowhere any time soon in the east. In fact, some guidance shows much of the Northeast may struggle to get above freezing before the end of January

For those in the NYC market-- I will be interviewed on Fox 5 at 7:15PM about the impending winter storm.

As Euro ensembles gradually come into better agreement on their swath of heaviest snow, the Euro EFI becomes very useful. It tells us how unusual & extreme a specific weather variable can be based on thousands of reforecasts over a 5-week period centered on that day.

Good morning! Here are the newest Key Messages posted this morning.

WSO probabilities for snowfall totals exceeding each forecast office's warning criteria are at least 50% from central New Mexico to Long Island. That is one large >80% area from central KY to The Jersey Shore too. Snow will fall, lots of snow, over a large swath of the country.

Here were the latest WPC Key Messages regarding the impending winter storm and extreme cold. Each time I post these, the probabilities for Moderate Impacts keep going up.

For the Northeast, there remains notable spread in the deepening shortwave in the Midwest & the southwest trough for Sunday. Plus lingering uncertainty in the strength/position of the confluent flow over the Northeast. Placement of the heaviest snow/ice, p-type, & timing are still subject to change.

Here are the latest Key Messages for the impending winter storm and the dangerous cold.

Good morning! Here were the latest Key Messages issued eqrly this morning. Increasing area of at least 50% chances for Moderate Impacts (hazardous travel & to some infrastructure) from the Southern Plains to the Mid-Atlantic & Carolinas.

We initiated Key Messages for the impending winter storm late week and the extreme cold. Here they are--

It is going to be quite the 5 days on shift at WPC.

Decided to do a preview for next week's winter storm potential (not just Northeast, just the setup). Season-to-date, a strong 500mb ridge over the Four Corners & southern High Plains has effectively killed Gulf moisture, illustrated by the northerly 850mb meridional flow anomalies.

The National Weather Service will host an onsite hiring event at the upcoming AMS Student Conference in Houston

There are plenty of weather highlights in the lead up to Christmas & shortly thereafter for the CONUS, but wanted to give a shoutout to Fairbanks, AK which has been absurdly cold even by their lofty standards. Idc who you are, -35F for a high & -43F for a low on Sunday is brutal.

WPC's Winter Storm Outlook highlighting the probability of snowfall totals surpassing warning criteria for tonight/Sunday AM snowfall. Parts of northeast MD, southeast PA, southern NJ, & northern Delaware showing >50% chances. Speckled 30-50% areas in Long Island & southeat MA.

Philly looking like the epicenter for this wintry setup tonight and into Sunday morning. WPC's Probabilistic Winter Storm Severity Index showing high chances (70%) for Moderate Impacts within the immediate Philly metro area. #pawx #njwx

Before winter goes on hiatus for portions of the Mid-Atlantic in the final weeks of 2025, the I-95 corridor finally gets a shot at accumulating snow tonight & into Sunday morning. The WSSI shows Moderate Impact potential from northeast MD & northern DE to Philly & southern NJ.

Looking forward to joining the wonderful folks at WeatherBrains tonight to talk all things WPC!

A strong clipper will make is way through the Upper Midwest on Tues., across the Great Lakes Tues. night, & head for the Northeast on Wed. Large area of >60% chances for at least Minor Impacts on Tuesday & into Wednesday AM due to a combination of heavy snow & blowing snow.

Southern VA braces for their second disruptive winter storm in four days with as much as 2-5" of snowfall today. Moderate Impacts (hazardous travel) stretch from Roanoke on east through the Richmond/Petersburg metro areas & to the I-64 corridor between Richmond & Norfolk. #vawx

Two winter storms will cause dangerous travel conditions across the northern tier of the country into the weekend. Here are the latest Key Messages for these storms.

Following the ongoing winter storm across the Upper Midwest, another storm system is forecast to impact parts of the Midwest and Great Lakes with wintry weather this weekend. Keep an eye on the forecast and check weather.gov for more information. ❄️

My shot of tonight's aurora from Manchester, MD.

Happy Halloween to all the witches, ghosts, ghouls, and K-Pop Demon Hunters slaying demons on their way to getting candy tonight!

This meso loop of #Melissa from CIRA is absolutely stunning at it makes its closes in on landfall in southwestern Jamaica. rammb-data.cira.colostate.edu/tc_realtime/... #hurricanemelissa

896mb. Outrageous. #Melissa

Watching this game: "3 turnovers inside KC territory is maddening and it is same old, same old" What the score says: "7-7 at halftime in KC? Have to take that."

Seeing the eye steadily warm/dry out from where it was 4 hours ago (1430Z) to where it is now (1830Z) is another clear sign of #Melissa strengthening. Each HH pass through the eye is showing a warming/drier mid-level layer. And a lower pressure reading each time, of course.

While the track is coming into much better agreement, there remains a good deal of spread regarding when #Melissa makes its NE turn. @burgwx.bsky.social's page shows some members are lagging SW of Jamaica while some are more progressive.

06Z HAFS-B pressure forecast was closer to what HHs were observing earlier today. It shows another period of RI starting sometime tonight and into Monday morning. Given #Melissa has another 48 hrs over the Caribbean, it unfortunately still has time to strengthen prior to landfall.

Comparison between this morning & evening NOAA tail Doppler radar data shows Hurricane Melissa rapidly intensifying. Will be a major hurricane soon and a generational storm for Jamaica.

Tail Doppler Radar (TDR) data from the current recon mission into Melissa shows that the vortex is vertically stacked up to 15 km w/ the upshear/NW quad being the strongest. This is about as favorable of a vortex structure as you’ll see for rapid intensification Plots from @cyclonicwx.bsky.social

One thing I am watching closely tonight is the short-term motion of #Melissa. Google DeepMind ensemble has been pretty consistent in showing a WSW motion beginning tonight, & this appears supported by the ECMWF deep-layer steering-flow as the hurricane becomes vertically deep. Diagnosed below ⤵️

Latest Vortex message for #Melissa now states the eyewall is closed. Full steam ahead on RI.