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It’s Tuesday Morning: What the hell happened?

I think we’re best to start off by saying this: Today is a really, really tough day for meteorologists. As everybody wakes up and steps to their window, they’re going to be disappointed in the amount of snow that has fallen. The exception will be over interior Connecticut, Long Island and New England — where the Blizzard of 2015 did bring the anticipated snowfall accumulation. Elsewhere, disappointment will be widespread as snow totals only added up to those of a moderate to significant snowstorm. The prolific snowfall amounts, seeded somewhat by hype but then backed up by our best computer models just mere hours before the storm, did not and will not come to fruition. Which leaves us only with one question: What the hell happened?

Back on Sunday evening, in our post breaking down the potential event, we included this very important piece of information: ” Very heavy snow will spread northwestward from the Western Atlantic to the NJ Coasts and Long Island by late Monday Night into the wee hours of Tuesday Morning. The westward extent of this precipitation shield is currently extremely uncertain — and will determine whether the storm is significant to major, or historic. In this heavy banding, snowfall rates of 2-4” per hour at times are likely.”

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Potentially historic blizzard expected Tuesday

Click here to check out our live blog with the latest information on the blizzard beginning at 8pm tonight.

Forecast models have trended dramatically in favor of a significant Nor’Easter, developing off the East Coast of the United States on Monday Night into Tuesday. The pattern features a very complex evolution of events, but favors a higher than normal likelihood of a significant low pressure system and precipitation developing along the East Coast, with higher than normal confidence in significant snowfall especially along the coastal plain.

Aloft, a significant upper level trough will eject southeastward toward the Ohio Valley and eventually to a position in the Southeast States. With a closed 540dm isopleth, this mid level trough is quite amplified. Mid and upper level heights will respond to this amplification along the US East Coast, with a pulse of the Western Atlantic Ridge. This will allow for mid level winds to become oriented south to north along the Eastern Seaboard.

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Live Blog: Nor’Easter, blizzard likely Tuesday

Final Snowfall Totals: A full list of (mostly accurate) snowfall reports can be found with these two links:

Upton National Weather Service Reports

Mt. Holly National Weather Service Reports

These may be subject to further updates since a lot of the reports are old (we are awaiting the final numbers from NYC and LaGuardia Airport). But generally speaking, NYC through Brooklyn and Queens had 10-13″, Nassau County had 12-18″, Suffolk County had 18-30″, but areas west of NYC generally received much less snowfall. The gradient was quite sharp, as most people from Nassau County and east got close to or as much snow as was expected, but the heavy snowfall banding did not make it that far west. We explain the forecast bust here.

Overnight 1/27: We actually lost internet, so updates were tough to come by. The heavy banding from the ocean produced consistent whiteout conditions in Suffolk County, occasional whiteout conditions in Queens and Nassau, but not very much west of that as the air remained very dry just to the west of the band. In an area of heavy banding, there is very strong lift, but the atmosphere has a balancing act, so that often just to the west of areas with strong lift — especially with a storm that passes well to the east — there is an enhanced area of subsidence, that prevents the band from crossing further west.

Here is a video of the near-whiteout conditions in Rockville Centre, NY:

9:00pm 1/26: West of NYC was always supposed to be an area where snowfall totals could theoretically rapidly drop, and the latest NAM model hints at this. Heavy snow on the new run literally hits a wall in NYC, and doesn’t make it much further west than that. Whether it’s right or not we don’t know, and the latest observations still do show a westward push to the radar. But the idea of a strong cut-off west of NYC could be a realistic idea.

Areas east of NYC still look to do very well in the snowfall department.

7:10pm 1/26: Technical Update: For those who are worried about the HRRR not showing much snow for the region, we have a couple of things to say:

1) The latest HRRR is a bit west of its previous run.

2) More importantly, meteorologist Phillippe Papin made the astute observation that the HRRR can suffer problems with retrograding coastal systems. When precipitation is over the ocean, the HRRR can only see what the radar sees, since currently radar reflectivity is implemented into it. The radar in itself has a limited understanding of latent heat release with deepening ocean cyclones that does not occur with cyclones over land (the ocean has a lot more moisture than the land for latent heat release!) This could cause the HRRR to see the storm as being weaker, and thus make it more prone to jump the cyclone towards convection and push the storm further east.

6:45pm 1/26: The push westward has begun! The ocean banding has already pushed into most of Long Island, and should be in NYC by 8:00pm, and continue to push westward from there. Snowfall will gradually get heavier as it approaches, but the heaviest snow will be after midnight.

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5:00pm 1/26: Governor Cuomo has announced that the entire NYC Subway system will be shut down at 11:00pm tonight.

4:15pm: A very heavy snow band has set up near NYC, in Queens and Long Island. LaGuardia airport has reported 2″ in the last hour! New Jersey remains to the west of this band so their snowfall totals are much lighter.

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There are hints that the precipitation in the ocean is merging with the band and trying to back NW towards the coast, though that hasn’t happened decisively yet. What we need to watch is the progression of this precip — the models that give us heavier snow have a clear westward leaning towards that precip by 7:00pm. We would like to see that occur if the snowier models are going to verify. As of now, areas east of NYC look great for 15″+ of snow, but there are still uncertainties from NYC and west.

3:05pm: Latest NAM model confirms the observations of the trough being more negatively tilted than forecast. It takes the storm and tucks it in west off the NJ coastline and stalls! Amounts would be exceed 2 feet in many locations if this run were to verify. Note: This is NOT our forecast, but it could indicate that the heavier snow amounts may extend further west, like previous European Model guidance.

2:40pm: Snow has already greatly picked up in intensity, and is coming down moderately to heavily at times. Many locations have already reported 2-3″ of snow in our area, with nearly 1″ per hour snowfall rates. We think this is because the negatively tilted trough has allowed for some isentropic lift to be oriented from SE to NW, and then some convergence once that fetch hits the land adds to the lift, allowing snow to form. It also allows snow to reform at the shores instead of moving away, because the convergence keeps feeding more snow bands. These snowfall rates are expected to continue for at least the next hour or two, creating a very messy evening commute. Roads are already quite treacherous.

9:30am: Well, the European Model is king. The NAM model just came in and showed a 100% textbook scenario of how to get historic snowfall in the NYC area. It closes the 500mb low to our south and stalls the surface low, while the 700mb low and lifting is absolutely ideal for heavy banding.

Today's NAM model valid for early tomorrow morning is textbook for snow, as the 500mb low and 850mb low are closed off in perfect spots for heavy snow, and heavy banding just sits and spins over our area.

Today’s NAM model valid for early tomorrow morning is textbook for snow, as the 500mb low and 850mb low are closed off in perfect spots for heavy snow, and heavy banding just sits and spins over our area.

As far as current weather conditions, the initial burst of snow has overperformed somewhat. And while there may be a brief lull in the action this morning, bands of moderate snow are forming in S NJ and heading our way.

8:35am: We’re back in action this morning! Not much has changed overnight. Light snow continues to fall throughout much of the region. This is occurring due to a weak disturbance aloft, riding out ahead of the main show later this afternoon. There is enough moisture in the atmosphere to produce light snow. This is modeled to continue throughout the day today, with banding slowly working northwest from the Western Atlantic Ocean through New Jersey and eventually toward NYC tonight. Roads will become progressively worse after around noon today. So if you have to travel tonight, we recommend making plans to do so earlier. Our forecast has not changed and our Storm Total Snowfall map remains the same as it was yesterday. Our forecasters are working on any potential tweaks and attempting to refine the map as best as possible.

The NWS Watches and Warnings included below also remain unchanged. Hang tight for updates today!

1:15am 1/26: What a rollercoaster of model runs. Other guidance had backed off a bit as well, but was still very close to the bigger amounts. This led to the big question: would the Euro model hold? And that it did. It still gives the NYC area 2 feet of snow and locally higher in some spots. That is not our forecast, but it does seem to question the models that backed off. The key was that the European model did not shove the surface low towards the area of convection, and instead it got captured and turned NW, like old runs. It actually deepened even more than the previous run, though it did tick slightly east — which really only reduces snowfall for W NJ and E PA.

This will be quite the interesting forecast.

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Tremendous Nor’Easter, significant snow possible Tuesday

All of those cold and snowy winter forecasts may finally be validated. All of the latest numerical weather guidance has taken a rapid turn towards showing a significant winter storm — with blizzard conditions — affecting the entire area on Monday night into Tuesday. Although plenty of uncertainty still exists in regards to the details, it is becoming safe to say that a snowstorm or large proportions will be affecting the Northeast.

Currently, the  piece of energy that is forecast to develop into our storm is still in Montana, and it is diving southeastward as we speak. Previous forecasts had this piece of energy moving more progressively, not turning the corner in time to crawl up the East Coast, and thus passing seaward. One potential reason for this was because at the time, the piece of energy was still in the NE Pacific, where our data is quite limited. Once that piece of energy reached British Columbia last night, models were able to get a better idea of just how strong this system is, and have rapidly adjusted their forecast evolution of the feature — now indicating that will become much more amplified.

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The meteorology behind this weekend’s Nor’Easter

This winter has not had a fair share of wintry events. The snowfall we have received has generally come from clipper systems, and the larger storm systems have been rain. But the weather pattern is changing towards one that favors major east coast storm development and potentially large snowfall events. It is not a slam-dunk by any means, since there are a lot of moving parts, but the pattern over the next few weeks certainly piques the interest of any meteorologist looking for potential winter weather events.

One of the main problems for getting major snowstorms this winter has been the very fast flow across the Pacific and Atlantic basins. This means that any large storm that tried to amplify would get flattened out, as any ridging in the Pacific would get flattened like a pancake. This is going to change as we head towards this weekend.

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