Mild Weather For February Break

President's Day marks the beginning of February vacation week for most schools across Massachusetts.  Growing up, sometimes this week brought heavy snow and sometimes temperatures crept into the 50's/60's.  Temperatures in the 50's and 60's in February are often just a tease and are followed by some mid-winter cold in early March.

By the end of that week in 2000, we had put down the hockey sticks and picked up our baseball mitts.  In 2003 we had the snowboards out until the beginning of April so you never really know.  The 2003 storm was rated as a "category 4 crippling" snowstorm.  The 27.5" is the all-time record for a single snowstorm at Logan Airport.  This is a very breakable record for Boston and I would expect it to fall in my lifetime (I'm ~28).

Northeast Snowfall Impact Scale (NESIS) Presidents Day 2003

Much of the United States has been warmer than average so far in 2017.  The Pacific Northwest and New England are the only regions of the country near or below average.

Month to date 2 m temperature anomaly (image Weatherbell)

By this time next week, I expect Southern New England to be safely in the red.  Temperatures today and tomorrow are seasonable before a multi-day warm up heading into this weekend.

General Overview/Short Term Forecast
Temperatures maxed near 60 yesterday.  It will be 10-20 degrees cooler today.  Canadian high pressure will temporarily re-take control of our weather pattern.  I expect mostly sunny skies with max temps in the upper 30's/low 40's.  Winds increase out of the north this afternoon.  Wind gusts of 20-30 mph are likely.

NWS Max temps Monday (image Weatherbell)

Low temperatures tonight drop into the upper teens and low 20's.  Clouds will increase Tuesday afternoon as warm front approaches from the Southwest.  Temperatures should remain in the low to mid 40's, although sea breezes at the coast could keep max temps in the upper 30's,

WPC Surface Fronts/Precipitation Tuesday 7 AM 

Some light rain or freezing rain is possible Tuesday night into Wednesday AM.  Temperature trends tomorrow will have to watched just in case local highway departments need to treat some roads.  I don't think this is likely, but there is a chance.

Wednesday-Saturday
A storm system will develop in the 4 corners region of the US and move through the Central Plains towards the Great Lakes.  This storm system will produce a major snowstorm across the Upper Plains and parts of the Great Lakes by the end of the week.  Wednesday is in the low to mid 50's,  Thursday appears to be the warmest of the bunch with temperatures approaching the 60's.

00z EURO 500 mb height anomaly Thursday 7 PM (image Weatherbell)

High pressure offshore the Mid-Atlantic and zonal flow from the Pacific will combine on Thursday to bring temperatures well above average.  The 2-24-00 map is pretty close to this (without the cut off near FL).

WPC Daily Weather Map 2-24-2000 7 AM 500 mb

Here are the current max temps forecast on Thursday.

NWS Max temp forecast Thursday 2-23-2017 (image Weatherbell)

The NWS in NYC and Philly are going for the 70's!!  I am researching northeast US late Feb temp records and I will post on that tomorrow.  Friday may be just as warm but we will have to watch for a back door cold front keeping temps in the 40's.  Here is the projected surface chart Friday 7 AM.

WPC Surface Fronts Friday 7 AM

This system impacts Southern New England with wind and rain later Saturday.  I'll be tracking this all week.

-Zack Green

Some Precipitation Today, Snow Shot Tonight

Recapping Winter Storm Orson

For the second time in four days, a storm system dropped plowable snow in Southern New England.  The first storm produced more snow and was quite frankly more impressive from a physical science perspective at its closest approach to SNE.  I expected more out of the snow yesterday.  I originally forecasted 10-14" for much of MA and 14-20" for the Merrimack Valley and points north.  

Total Observed Snow through 830 AM via NWS Boston

I did not expect the blotchy nature of the radar yesterday afternoon.  I also thought there would be more snow in the predawn hours.  There were signals in the guidance that low snow totals were possible, if not likely.  

Link to 24 hour MA radar loop via WOWeather

I used a similar method to derive snow totals as I have all winter but it wasn't good enough yesterday and I will be better in the future.  Props to NECN and Fox 25 for keeping their snow totals low.  My sincere apologies to those who use my weather information to make decisions, this was not my best work.

NOAA/NWS/NCEP GOES_East Rainbow IR Satellite 645 AM

Here is the surface chart as of 7 AM.  The central pressure of the system is down to 977 mb.  We have an official meteorological bomb with a greater than 24 mb pressure drop in the last 24 hours.

WPC Surface Analysis Monday 7 AM

There is some light snow in Eastern MA but the substantial snow is in Maine.

NWS Northeast Regional Radar Loop through 818 AM

Temperatures are in the upper 20's right now and will max out in the upper 20's/low 30's depending on location.  

NWS Maximum Temps Monday (image Weatherbell)

If you have stepped outside it feels much colder than the upper 20's and that is thanks to the wind.  Wind chills should be in the teens most of the day before dropping to the low teens overnight.  The winds are strong enough to prompt headlines from the National Weather Service.  A *High Wind Warning* is in effect for Eastern MA/RI until 7 PM for frequent gusts near 55 MPH.  Thanks to the heavy wet snow on trees and powerlines these NW winds pose a greater danger than normal for power outages.  A *Wind Advisory* is posted for Central and Western MA and CT for the wind gusts 40-50 mph.  This is also until 7 PM.

NWS AM Headlines

More sun than clouds today as the low sits and spins to our east.  High pressure will build from the west.  By 7 PM here is what the surface chart should look like.  Please note the low in the top center of the image and the mess in the Texas, New Mexico, and Oklahoma region.  

WPC Surface Fronts/Precipitation Monday 7 PM

There was a chance these two features would come together off the east coast on Wednesday and create another major winter storm.  It now appears this will come together too late to impact the east coast with a major storm.    The northern system will bring some wintry precipitation to New England on Wednesday.  Before we get to that temperatures tonight are in the low to mid teens.  

NWS Min temps overnight Monday to Tuesday AM (image Weatherbell)

The weather Tuesday will be seasonable (perhaps a few ticks below average) with temps in the low to mid 30's and light NW winds.  Temps on Wednesday start in the 20's but quickly surge into the low 40's.  Snow may break out for the morning rush but this will quickly lift north.  In fact, most of the snow will be in Northern New England.  So rain/snow mix is likely in the interior and just plain rain at the coast.

-Zack Green

Evaluating the Storm So Far

There is already 2-4" of snow on the ground across portions of Southern New England, including my front walk.  The storm has not really developed yet and this is still the initial surge of precipitation.   On satellite, we do not yet see the classic comma head that most Nor'Easters have.

NOAA/NWS/NCEP GOES_East Rainbow Satellite 1245 PM

Outside of the immediate coast and the Cape and Islands, this storm is mostly snow at the moment.  Light precipitation began between 10-11 AM.  Snow began to stick around noon time so we are on an inch per hour pace at the moment.

NWS Northeast Regional Radar 208 PM

There really isn't much to look at on the surface chart right now.  A weak low-pressure system in Western PA and the DMV is only at about 1005 mb.  This is resulting in the fragmented precipitation shield.

WPC Surface Analysis Sunday 1 PM

A *Winter Storm Warning* remains in effect until 7 PM Monday for most of MA.  A*Blizzard Watch* is posted for coastal MA and the Cape and Islands from 4 AM to 7 PM Monday.  The NWS Headlines Map has a lot of hazards highlighted.

NWS Early PM Headlines

In the next 3-4 hours expect moderate to heavy snow accumulating 1-2" per hour,  Temperatures in Central MA are still in the 20's so the snow is still light and fluffy.

19z HRRR 2 m temps 2 PM (Image Weatherbell)

These temperatures will slowly increase this evening, topping out around 31-32 in Worcester County.  It will likely be a few ticks warmer in Eastern MA.  So the consistency of the snow is cement in CT.RI, and E MA but not so bad in C and W MA at the moment.  Here is the projected radar for 7 PM.

19z HRRR sim radar Sunday 7 PM (image Weatherbell)

The low at 7 PM will be south of New England, near Long Island with a pressure of 997 mb.  A low tracking will send keep the wind out of the east so temperatures will stay in the low 30's until the pre-dawn hours.  The snow in Central MA will go over to cement like during this time period.

WPC Surface Fronts/Precipitation Sunday 7 PM

The snow may let up a bit in Central and Western MA between 9 PM and 2 AM.  Boston will keep cranking as the low undergoes bombogenesis.  We are looking at a weather bomb folks, right off the MA coast!!  The 1 PM pressure is 1005 and it should be down to 973 by 1 PM tomorrow, a greater than 24 mb pressure drop in 24 hours.  Here is the radar at 5 AM.

19z HRRR Sim Radar Monday 5 AM (image Weatherbell)

Snow lets up just after 7-8 AM in Central MA. Snow will last into Monday afternoon in Eastern MA and the Cape and Islands with high winds.  The pressure by 7 AM is down to 978 mb.

WPC Surface Fronts/Precipitation Monday 7 AM

As for my snow totals, I will bring them down slightly.  Instead of 14-20 it is 12-16, 10-14 is 8-12 now etc.

Now let's talk about the winds.  They will really begin to increase after 4 AM.  Winds gusts over 40 MPH are likely until early Monday evening.  Any snow that falls Monday will be wiped through the air.  Temperatures will be in the upper 20's Monday.  The winds will make it feel like the teens.  The outer Cape, Cape Ann, and Nantucket will see winds approaching 60 on Monday.

NWS Max wind forecast Monday 4 PM

 The wind finally lets up after 10 PM tomorrow evening.  The reason for the long duration wind barrage is a 973 mb low to our east and a 1029 mb high to our southwest.  The atmosphere is squeezing a lot of air through the region.  There will be power outages throughout New England.

WPC Surface Fronts/Precipitation Monday 1 PM

At this point Winter Storm Orson will look gorgeous.  The weather geek in me wishes that low was 40 miles southwest but that would be a devastating storm in Southeastern MA.  Portland, ME will really get pounded.  Tomorrow would be a fun day to be at Nubble Light in York, ME.

-Zack Green

Saturday Weather Thoughts

A second major winter storm in four days will impact Southern New England Sunday afternoon into Monday.  Snow will approach double digits but this will be a much different storm when compared to the Thursday storm.  Temperatures will not be as cold during the storm so the snow will not be light and fluffy in nature.  It will be the heavy and wet paste that can cause a lot of problems for trees, power lines, and hearts.  A rain/snow line will exist in SE MA/RI.  Winds will also approach blizzard levels for a time overnight Sunday into Monday.  It does appear the storm will sit far enough away from the SNE coast to limit "blockbuster" potential.  Still, 8-14" of snow will be common across the region.

General Overview

Thursday's storm largely was born out of the Southern branch of the jet stream.  Energy consolidated near the Carolina's and rapidly strengthened as it passed south and east of New England.  Tomorrow's storm will originate out of the Northern Jet Stream.  The storm will lack a storm low center as it gets close to the New Jersey coast Sunday afternoon.  Overnight Sunday into Monday the low will deepen and slow as it is near the Eastern MA coast.    

NWS/NOAA/NCEP Water Vapor Satellit through 915 AM

It's not impressive on satellite at the moment.  One piece of energy is leaving the Rockies and is emerging in the Great Plains.  A second piece is up in Alberta/Saskatchewan.  We can see these features better on the surface analysis.  Here is the 1 PM forecast surface fronts and precipitation.

WPC Surface Fronts/Precipitation Saturday 1 PM 

The Canadian feature will drive the overall development of this low.  It won't even begin to explode until it is east of the region.  Here is the upper air pattern Sunday at 7 PM and Monday at 7 PM

click to enlarge images via Weatherbell

Here is what it will look like at the surface Sunday at 7 AM and Monday 7 AM.  Clicking these images and opening in another browser makes it make easier to see.  

Click to enlarge

Timing/Impacts

Precipitation begins between 10 AM and 1 PM from SW to NE across Southern New England.  That said be careful Saturday night.  Some light freezing drizzle is possible in Eastern MA including Worcester County.  Keep the speeds down.  Max temps will get into the low 30's this afternoon before dropping below freezing again tonight.  Temperatures will be in the low 30s when snow/freezing rain begins.  Here are the 1 PM tomorrow forecast temps.

12z NAM 3km hires 2 m temps Sunday 1 PM (image Weatherbell)

With that temperature profile, precipitation will be as rain, sleet, and freezing rain in Eastern MA.  The heaviest snow for Central MA does appear to be during the first part of the storm on Sunday.  By 7 PM temperatures are near 32-33 across much of Southern New England.

12z NAM 3km hires 2 m temps Sunday 7 PM (image Weatherbell)

That means that most of our snow will be like cement.  It will be hard to move and it will likely stick to everything.  The rain/snow line will also make a run towards Boston, Worcester, Hartford, and Providence.  Usually, the heaviest snow falls just to the left/north of the rain/snow line.  At 7 PM that would put Southern Worcester County, Norfolk County, and Suffolk County in the prime zone.

12z NAM 3km hires precip type Sun 7 PM (image Weatherbell)

I think Boston may go over to rain thanks to an east wind. Worcester will be safely all snow.  After midnight the heaviest snow transfers towards NE MA and NH/ME.  Around 5-7 AM cold air will return so any snow at the end of the event will be of the powder variety.  Winds will pick up overnight Sunday into Monday which will blow the poweder around.  Here are the 7 AM temperatures Monday.

12z NAM 3km hires 2 m temps Monday 7 AM (image Weatherbell)

Snow may hang on into Monday AM which is a trend to watch tonight and tomorrow.  So here is what I am thinking,

The wind will gust 35-45 mph on Monday in the interior and 55-65 MPH at the coast.  Keep the electronics fully charged tomorrow.   North facing beaches on the Cape could see some coastal flooding.  This means all of Cape Cod Bay including Sandwich and Dennis who will be at risk for storm surge Monday afternoon.  Periods of snow showers will continue Monday early afternoon before conditions clear.  Schools should be ready open Tuesday.

I'll post another update tomorrow morning.

-Zack Green

Tracking Winter Weather Threats Over Next Few Days

Winter Storm Niko delivered yesterday and helped wipe out the seasonal snow deficit in all of the four major climate sites.  The storm will be remembered for the heavy snow band that dropped 2-4"/hr yesterday afternoon and for all of the lightning and thunder that it produced.  Thundersnow occurs when ice/snow crystal are carried high into the atmosphere by strong vertical motion (or updrafts).  When the charge separation becomes too great the atmosphere returns to equilibrium by a lightning strike.  Yesterday's storm had a lot going on physically that enabled over 100 strikes.  I didn't see/hear any yesterday but I do remember my first thundersnow experience.

Jim Cantore Thundersnow Worcester, MA  12-7-1996

Here is the radar loop from yesterday.  It took awhile to get going in parts of Eastern MA but once the storm got cranking so did the snow.

Intellicast 24 hour radar loop Thursday 2/9/2017

I rate this one as a major, memorable storm.  It's not in the top 10 for me but I will remember all the lightning I saw on radar and the intense snow band yesterday afternoon.  Several schools had their first snow day yesterday.  I don't believe it will be the last.

NWS Boston 2/9/2017 totals, year to date, average to date via NWS NOWdata daily almanac 

Short Term Forecast
Yesterday's storm is off in Atlantic Canada. Winds will increase this afternoon as cold air is re-enforced across the region.   At the same time, a warm front is steadily advancing NE.   The two air masses will clash and snow will fly again overnight into Saturday AM.   Temperatures this afternoon max out in the low to mid 20's before dropping back down into the teens overnight.   The warm front will be driven by an upper-level ridge that will is moving to the east.

NOAA/NWS/NCEP GOES Composite US water vapor satellite 1215 PM Friday

The low pressure that will responsible for tonight/tomorrow AM snow is currently in Manitoba, Canada.  This clipper (or Manitoba Mauler) will combine with the air mass clash from the warm front/cold air to drop a few inches of snow.  This will be minor but I think it's enough to get the plows/sanders out. Here is the forecast surface chart at 1 AM tonight.

WPC Surface Fronts/Precipitation Saturday 1 AM (image Weatherbell)

Snow begins around 10 PM tonight.  It will not really begin to accumulate until 1 AM.  Maybe 1-2" by 5 AM will be on the ground.  Another 1-2" is likely Saturday AM before temperatures climb into the 30's and we a get a brief break from the snow.  The last snow will move offshore by 11 AM.

16z HRRR Sim Radar Saturday 5 AM (image Weatherbell)

Temperatures climb into the low 40's in CT, RI, and SE MA tomorrow afternoon.  Temps will be in the upper 30's in C MA and NE MA.

NWS Boston Max Temps Saturday (image Weatherbell)

Saturday Night and Beyond
The atmosphere is primed for snow and the weather pattern is set to deliver.

WPC Surface Fronts/Precipitation Sunday 7 AM

The Sunday AM weather map does not look all that spectacular.  The original low will not explode until it gets into the Atlantic Ocean.  Still, precipitation is set to begin before noon time on Sunday.  It may begin as some sleet and rain before going over to a heavy wet snow Sunday afternoon.  Parts of SE MA will be mostly rain on Sunday.  Bristol, Plymouth, Barnstable, Kent, Newport, Washington, Dukes, and Nantucket counties will likely see rain for awhile Sunday afternoon.  Everyone goes to snow overnight Sunday into Monday.

WPC Surface Fronts Monday 2-13-17 7 AM

How much snow falls during the day Monday depends on where the low stalls in the Gulf of Maine.  If it is close like the WPC believes more snow falls for a longer period of time Monday.  If the low is further out to sea snow ends after 7-9 AM Monday.  This is what I will be watching for as I go over the data this weekend.   Another problem will be the winds.  This storm will get strong, quickly, Sunday night.  Blizzard warnings will be needed for parts of the area.

This next storm will be more difficult to forecast because there is a lot going on.  As of now (1 PM Friday) I expect snow to begin before noon in Worcester County and points north/west.  It really cranks between Sunday 1 AM and Monday 1 AM.  I expect areas that stay all snow to have double digit snow totals.  Temperatures will also drop for the second half of the storm as the low moves into the Gulf of Maine.

I will update tomorrow.

-Zack Green