Tuesday, February 7, 2017

Winter Storm Watch Issued For Thursday (UPDATE 2/8/17 630 AM)

There are not many changes to the forecast the way I see it this AM.  The NWS has upgraded the Winter Storm Watch to a *Winter Storm Warning*.
NWS Boston AM Headlines
Temperatures this AM are below freezing along and north of the Pike.  Count the Blackstone Valley as one that is "along" the Pike.  I am seeing readings still in the 20's as of 630 AM.  It's 51 in New Bedford, 30 at Worcester Airport, and 26 at Logan Airport,  A surface low developed in the Gulf of Maine.  The counter-clockwise circulation is helping to keep the cold air in place.
WPC Northeast Surface Analysis 4 AM 
That warm front will make it to the Pike and that is it!  I don't foresee the high temps in the mid to upper 50's in Boston and Worcester today.  Those should be confined to SE MA.
NWS Max temp forecast Wednesday (image Weatherbell)
I think these numbers are a tad high but we will see.  Snow still looks to be 8-12".  A think a band of 12-18" will set up across Central and Eastern MA but I don't know where yet.
NWS Max snow accumulation forecast (image Weatherbell)
I'm supposed to attend a show tonight so we will see if I can get a new post up before tomorrow AM.  Timing of the storm below.

(Original Post below)
I'm not sure what teachers, snow removal technicians, and winter weather weenies did after my "State of the Southern New England Winter Address" last week but I think it worked.  Cold air this morning won the battle and held on hours longer than the computer models and the humans who interpret them believed.  I only speak for myself but perhaps I should have been paying more attention to the weather and not re-watching the 4th quater of the Super Bowl 4-5 times.  A large swath of 2-4" of snow has fallen so far north of the MA Pike from Deerfield to Boston.  Logan Airport has recorded 2.5" today to help out the seasonal snow total a bit.  A larger, stronger, and colder storm will pass south and east of Nantucket on Thursday.  This storm will potentially knock out the seasonal snow deficit completely 
SB Nation Screen grab of Boston during Pats parade
The National Weather Service in Taunton has issued a  *Winter Storm Watch* from Wednesday at 10 PM until Friday at 2 AM for all of Southern New England, except Nantucket Island.   A winter storm watch means a significant snow, sleet, or ice storm is possible within 36-48 hours.  Early snow calls are for 8-12".  The storm track will lock Arctic air in place as scoots to the SE.  Temperatures Thursday night into Friday morning will be around 0 with wind chills -10 to -15 below.  Perhaps I should have just kept silent about the mild winter with the hope that mother nature would not notice

General Overview and Short Range Forecast
Here are the national surface analysis and water vapor satellite 2 for 1 deal.  The storm system in the Great Lakes will pass into Ontario.  The warm front will try force its way into Northern New England but it will be hard to get past the Northern MA border tonight.  Features 1 and 2 will help form our storm Thursday.
NOAA/NWS/NCEP Water Vapor Analysis/Surface Fronts
Cold air will hang on north of the Pike so expect slick conditions tonight.   This rain band is forecast to move through Southern New England between the 3-5 AM hours, ahead of the cold front.
20z HRRR Sim Radar Wednesday 5 AM
I expect some wind as this passes.  Before the cold air mass truly arrives tomorrow night temperatures will spike into the 50's south of the MA Pike!  It's not bad north of the Pike either with temperatures in the 40's. 
NWS Max Temps Wednesday (image Weatherbell)
These may be a little high from the National Weather Service.  It was in the 60's in the Mid-Atlantic so there is certainly mild air south of the frontal boundary.  These temperatures will melt some of the snow/sleet that fell today, especially north of the Pike. Temperatures will fall tomorrow evening back down south of 32.  Public works departments will probably have to treat the roads in Northern Worcester County and much of Northeast Massachusetts tomorrow evening.  By Thursday at 7 AM here are the surface temperatures in Southern New England.
12z NAM hires 3 km surface temperatures Thursday 7 AM (image Weatherbell)
By 7 AM Thursday, those two pieces of energy circled in the satellite chart will combine with upper atmosphere support to from a coastal storm off the Mid-Atlantic coast.  For once this winter the low will track offshore with cold air in place.
WPC Surface Fronts/Precipitation Thursday 7 AM
Thursday Forecast
There is the potential for the storm to slide a bit further south and east but I do not believe it will due to the strength of the upper atmosphere support.  Even if it does  I expect 3-5" of powder in a "worst case scenario".  Snow begins between 5-8 AM.  It will snow moderately pretty much as soon as it begins.  By 10 AM  expect 1-3" already on the ground.  Here is the simulated radar for 11 AM.
12z NAM hires 3km sim radar Thursday 11 AM (image Weatherbell)
Temperatures will fall to the upper teens/low 20's away from SE MA by noon time.  We will have moderate to heavy snow with Arctic temperatures.  
12z NAM hires 3km surface temperatures 1 PM Thursday (Image Weatherbell)
Snow will have the potential to pile up 1-3" per hour during the afternoon.  We are looking at 6-10" of snow by 5 PM.  The storm winds down between 5-8 PM Thursday with an additional 1-3" of snow.  That means, in general, I expect 8-12" but it could be as little as 5" or as much as 17-18".  
NWS Snowfall forecast through Friday 1 AM (image Weatherbell)
After the snow ends temperatures plummet into the single digits.  
NWS Minimum Temperatures Friday AM (image Weatherbell)
Winds will be a problem during the storm Thursday.  I don't believe blizzard criteria will be met yet there will be blowing and drifting snow during and after the event.  Wind chills Friday AM are forecast to be near Wind Chill Advisory levels (-10 to -15).   I will fine tune the timing and snow totals tomorrow.  I would expect school closings on Thursday.  

-Zack Green

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