Final Forecast for the January Blizzard of 2016

22 01 2016

A major blizzard will affect most of the Eastern seaboard starting tonight into Sunday morning. This storm will rival the 1996 blizzard in terms of intensity and snow totals. Blizzard warnings have been posted by the national weather service for many areas, including Washington DC, Baltimore, Philadelphia, and New York City. This blog post will overview the storm in three sections: snow and timing, wind, and recommendations.

Snow:

Currently, our storm is gaining strength in the southeast. Snow is currently falling in Virginia, Tennessee, and Kentucky. The low pressure is moving northeast and will exit off the Atlantic coast sometime Saturday morning. Light snowfall should start at around 10 PM tonight and progressively become heavier by Saturday morning. The image below of the 4K NAM shows steady snow moving into the region late tonight and early Saturday morning. Screen Shot 2016-01-22 at 9.22.24 AM.pngAs the low pressure moves off of the coast, it will strengthen further and the the wind and snow will pick up during the day on Saturday. Snowfall rates of 1-2 inches an hour are very likely from 10 AM to 6 PM on Saturday as the storm moves into open water. The 4k NAM image below shows the snow in the area becoming heavy tomorrow morning:

Screen Shot 2016-01-22 at 9.24.16 AM.png

As we head through the day Saturday, a lull is likely as the storm’s initial precipitation shield moves off the coast. This lull will occur during the afternoon or early evening on Saturday. By nighttime, the snow will pickup again and blizzard conditions will prevail until early Sunday morning.

Screen Shot 2016-01-22 at 9.37.43 AM.pngBy Sunday morning, the snow should slow down and eventually end from west to east.

Totals: 

Forecast models have projected snowfall totals ranging from 1 foot to over 2 feet. My forecasted totals are a blend of multiple models and are shown below:

 

Screen Shot 2016-01-22 at 11.01.48 AM.png

As the snow map shows, we are in for a snowstorm of historic proportions. Areas in Virginia and Maryland will receive the most snow, with some totals approach 3 feet! Our area will likely see totals 1-2 feet with locally higher amounts.

Wind:

Heavy snow is not the only factor of this storm. As the storm moves offshore, it will strengthen and bring in strong winds from the northeast (that’s why they call it a nor’easter). These winds will be strong, cold, and straight out brutal. At the peak of the storm, winds will be 20-25 mph with gusts up to 40. Along with the snow, it will create whiteout conditions on Saturday and Saturday night. Visibilities will be almost 0 and temperatures in the upper 20s. Additionally, there will be blowing and drifting snow, which will make it extremely difficult to clear the roads on Sunday.

nam_rapid---usne-30-C-10mwindarrows_white.pngRecommendations:

Please do not drive during this storm. With visibilities extremely low and heavy snow falling, travel will be nearly impossible on Saturday and even into Sunday. If you go outside during the storm, wear layers and make sure any exposed skin is covered. Travel will likely be limited into Monday as drifting snow and refreeze will cause issues early into next week.

Thanks all and don’t hesitate to comment with questions or concerns!

 

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We’re Back! Analysis of the Upcoming Nor’easter

19 01 2016

Hey everyone! I apologize for the scant number of posts during the past 9 months (zero as a matter of fact!), but Philaburbia is back for the rest of the winter season.

With a strong El Niño present, it’s been a very warm winter so far, with temperatures in Philadelphia running 13.7 degrees above normal in December. So far in January we are running around 2 degrees above normal. However, with El Niño beginning to weaken (see below) and arctic air starting to creep in, we are in for a stormy and colder February and March.

nino34Sea

Ocean Temperatures:

It’s been a very quiet winter so far with no major coastal system running up the coast. This, however, will change Friday and Saturday as a coastal system with abundant moisture will strengthen off of the Atlantic coast. I’ve explained to friends and colleagues, our warm December and January has resulted in extremely warm ocean temperatures off the coast. With warmer ocean temperatures, a low pressure system can strengthen quicker through sources of evaporation (this is why we primarily see hurricanes during the summer months, when the oceans are warm). As you can see from the map below, ocean temperatures have been nearly 3 degrees above normal:

atl_anom

Teleconnections:

Additionally, projected teleconnections have signaled the likelihood of a large disturbance. Both the NAO and AO (atlantic and arctic oscillations) are both headed toward a neutral position, with the AO doing so rapidly, following the storm.

Atmospheric Setup: 

The atmospheric setup is also favorable in the days leading up to the storm. All models are projecting a Canadian high moving in to provide cold air aloft while the low pressure moves into a benchmark position off the coast. Where the uncertainty lies so far is the location of the storm formation in the southeast. This aspect of forecasting is extremely difficult, since we do not possess the instruments necessarily to accurately predict the location of storm initialization. This brings us to our two scenarios:

Two Scenarios:

  1. GFS, Canadian: Storm moves exits coast at Virginia, follows up the benchmark and stays close to the coast. In this scenario, areas in Maryland would receive the most snow with other areas like Philly, NYC, and Boston all receiving over a foot of snow as well. This solution is shown below:

gfs---conus-90-C-mslpthkpcp_white

2. EUROPEAN: Instead of exiting the coast off of Virginia, the storm will slide further south and strengthen more quickly than anticipated before moving Northeast, away from land. While this scenario still projects a strong nor’easter, most of the heavy precipitation will be located off the coast. In the Philadelphia region, we would still receive a plowable snowfall, but nothing close to the 1-2 feet projected in scenario 1. The european is pictured below, courtesy of Accuweather:

ecmwfued---conus-108-C-mslpthkpcp6_white.png

Timing:

For both scenarios, the timing will be from Friday night into early Sunday morning. The major snowfall will occur during the day on Saturday. If scenario 1 plays out, we could see a prolonged period of 1-2 inch/hour snowfall rates Saturday afternoon. By midnight on Sunday, most of the snow should be finished with some scattered snow showers moving out by 3 AM on Sunday.

Regardless of which scenario is correct, this storm will be disruptive. I would advise against traveling at all from Friday night to Sunday morning until roads are cleared.

More updates coming with a final forecast on Thursday. It’s nice to be back.








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