Wednesday, January 22, 2014

BUST! Story Becomes Bitter Cold

No way to sugarcoat it- this will go down as a bust for everyone outside of 495 and North of the Pike.  Here was my map from Monday Night
Snowfall Map from 1/20/14
Here is what we have so far 
Skywarn Snowfall Totals 507 am (NWS Boston)
I should have trimmed the 6-10 and brought the 3-6 into Southern Worcester County.  I also should not have included Cape Ann.  I can't call the Cape a bust yet, but I think it will be hard for it reach 10" given the current radar presentation 
NWS Northeast Regional Radar
We'll see, but overall I am not happy with the forecast.  I have a feeling I'll have plenty of chances to try again before the winter is over.  Now the big weather headline is bitterly cold temperatures and wind chills for awhile.

Current Conditions/Short Term Forecast
Here are the temperatures as of 4 am
4 am 2 m temps (image Weatherbell)
Bundle up...wind chills across Southern New England are running -10 to -15.  Here is one models wind chill temps as of 7 am
08z HRRR Wind Chill Temps valid 7 am (image Weatherbell)
The storm is well south and east of New England
WPC Northeast Surface Analysis 4 am 
High temperatures today will range from 15-20 for most.  On the Cape temps will be in the 20's
06z NAM hires 2 m temps 2 PM (image Weatherbell)
Even though this map shows a Winter Storm Warning still for Eastern MA/RI this will be dropped soon.  A Wind Chill Advisory has been issued in its place through 10 AM
NWS Boston Advisories 
Tonight a good portion of Southern New England goes below 0
06z NAM hires 2 m temps 6 am Thur (image Weatherbell)
Temperatures stay in the teens tomorrow.  This is nasty stuff.  I'll update later today as there is the potential for light snow on Saturday, but maybe enough to get crews on the roads. 

Bundle Up

-Zack Green

Tuesday, January 21, 2014

Monday, January 20, 2014

Winter Storm to Impact Southern New England

The National Weather Service in Taunton has issued Winter Storm Warnings for all of Southeastern New England and Blizzard Watches for the Cape, Islands, and Southern Plymouth County.
NWS Boston Advisories 
Low pressure will develop along a polar front and intensify south of New England.  This will bring heavy snow and high winds to Southeast New England

The Set-Up
An approaching Polar Front will cause temperatures to plummet tonight.  The front is approaching Worcester now (449 PM).  It shows up nice on radar
NWS Boston Radar 438 PM
Here is the front in the surface analysis as of 1 PM.  
WPC Surface Analysis Northeast US 1 PM 
Here are the temperatures behind the front
2 m temps 4 PM (image Weatherbell)
This cold will be locked in place so there no precipitation type issues.  Now lets take a look at how this system will evolve.  Here is the current Water Vapor Loop
NOAA GOES_East Water Vapor Satellite (415 PM)
Low pressure will develop in the Tennessee Valley this evening/overnight.  Here is the upper level at 1 am Tuesday
18z NAM 500 mb vort/heights 1 am Tues (image NCEP)
A surface low will have developed in Eastern Kentucky and Tennessee
WPC Surface Forecast 1 am Tuesday
By 7 PM tomorrow night the upper level looks like this
18z NAM 500 mb vort/heights Tues 7 PM (image NCEP)
That is an exciting 500 mb set up for weather weenies everywhere.  Here is the projected surface chart at the same time
WPC Surface Forecast 7 PM Tues
Short Term Forecast
After the snow squall this evening temperatures will steadily drop.  The high temperature for Tuesday may occur at Midnight in some locations.  Temps are around 10 around 7 am for many in the interior.  Temps in the coastal plain will be between 15-20 
18z NAM hires 2 m temps 7 am (image weatherbell)
The temps do not rise much tomorrow.  The Cape and Islands stay in the 20s and will rise to near 30 during the storm.  Everyone else is 15-20.  Winds will be out of the north at 5-10 mph.  

The first light flakes start falling around noon time but steady snow arrives to the CT coast around 1-2 PM.  This spreads to SE RI and MA by 3-4 PM.  The precipitation will build into Central and Eastern MA by 6-7 PM.  Snow lasts until 6-7 am for everyone except Eastern MA.  In Eastern MA snowfall will stop by 10 am, with the exception of the Outer Cape.

The strongest winds will occur where the Blizzard Watches are posted.  On the Cape and Islands will will be sustained 25-30 mph with gusts to 50.  Nantucket and the Outer Cape will likely see isolated gusts to 60 mph.  Inland winds will be sustained 15-20 mph with gusts to 40, isolated 45-50.

Now for what you have all been waiting for.  First of all here are my observations on the storm.
  • Very cold, so a powdery snow like the 1/2/14 event
  • Storm will track South and East of "benchmark" so heaviest precipitation remains offshore
  • SE MA, Cape Ann the likely Jackpot areas
  • Tougher call inland due to precipitation rates
I have little doubt this will be a memorable storm for SE MA.  Its not often the Cape and Islands get a storm that is all snow.  I think ocean enhancement north of Boston will set up a jackpot band there as well.  A lesson learned on 1/2/14 was that the cold doesn't always mean high snow ratio's.  In general weathercasters assume for every 1" of liquid precip that is 10" of snow.  When it gets colder snow can fall at ratios of 20 or even 30/1.  We saw this in Eastern MA on 1/2.  However inland the snow growth zone was not as good so even though there was about 0.6 inches of precip, only about 6-8 inches of snow fell.  

Issued 606 PM 01/20/14
I'm going to try and post a video tonight or tomorrow morning.  Take care, feel free to ask questions.

-Zack Green

Saturday, January 11, 2014

Saturday NFL Playoff Weather

This is one of the best weekends of the year, Divisional Playoff Weekend.  Maybe that's because I am a Pats fan and my team is usually playing (12th time since 1996) but even in the rare off years the football is excellent.  Weather will impact both Saturday games. Without further ado...

General Weather
Two storms are affecting the Continental US today.  A powerful storm is affecting the Northwest while another storm impacts the Eastern US.  Here is the surface analysis
WPC Surface Analysis 11 am EST
Temperatures in the east are warm and while it will rain in Seattle, the mountains in the Pacific Northwest will get buried with snow.Notice how tightly the isobars (solid lines) are packed together around Seattle and Boston.  This will increase this afternoon/evening

New Orleans (+9.5) @ Seattle Seahawks  (O/U) 43.5  430 EST

Seattle is a difficult place to play regardless of the weather.  Temperatures at kickoff project to be around 45
16z HRRR 2 m temperatures valid 2 PM EST (image Weatherbell)
Temperatures may jump to 47-48 throughout the game but there will be no significant changes.  Rainfall on the hand will increase as the game goes.  There has been a lull so far this morning but the radar looks healthy 
National Weather Service Pacific Northwest Regional Radar Loop (138 PM EST)
Short range high resolution weather models agree on an increase in rain and intensity in Seattle this afternoon
12z NAM hires Simulated Radar 4 PM (image Weatherbell)
The final factor is the winds which will be sustained at 25-30 mph.  Gusts to 50 will be possible with any of the heavier rain bands
12z NAM hires 10 m winds 5 PM EST (image Weatherbell)
Indianapolis Colts @ New England Patriots (-7.5)  (O/U) 50.5  815 PM EST 
Gillette is also a tough place to play but recent playoff teams have come into Gillette and knocked out the Patriots.  Indy doesn't seem to be the type of team that can come into Gillette and win.  Baltimore and the Jets play tough defense and had swagger across the board.  But Andrew Luck looks legit so you never know.  Here is the current temperatures in New England
RTMA 2 m temperatures 1 PM ESRT (image Weatherbell)
Temperatures are in the upper 50's across Southeastern New England and these aren't going to fall much this afternoon into this evening
12z NAM hires 2 m temps 8 PM EST (image Weatherbell)
At kickoff the temp will be 57 at Gillette and will only fall to 53 or so by midnight.  Considering the Divisional Playoff Game 10 years ago at Gillette was the coldest game in Patriots history we'll take this.  That was the Tennessee game as the Pats won their 13th straight on route to a Super Bowl and a record 21 game winning streak.  

Rain will be a huge factor.  Here is the current radar
National Weather Service Northeast Regional Radar Loop (148 PM)
Short range guidance indicates a steady rain all game with the potential for a soaking rain in the first half. 
17z HRRR Simulated Radar 9 PM EST (image Weatherbell)
With these soaking rains comes high winds.  Sustained winds will be 15-20 mph with gusts up to 50 possible.  A wind advisory is in place from 4-11 PM at Foxboro so winds will also lessen throughout the game.  May want to look at second half lines for this game.  

Enjoy, I will post for Carolina-San Fran and Denver-San Diego tomorrow

-Zack Green

Wednesday, January 1, 2014

Winter Storm Impacts, Timing

Snowstorms are generally not a big deal in Southern New England.  This storm will be slightly different than others we've faced in recent years due to bitterly cold temperatures.  The National Weather Service has issued Winter Storm Warnings
NWS Boston Winter Weather Advisory

Set Up
Here is the current surface chart
WPC Surface Analysis 4 PM EST
Notice the cold front moving out of Canada?  Check out the temps behind it
2 m temps 6 pm (image weatherbell)
A weak low is moving out of Oklahoma while a boundary in the Gulf of Mexico collects moisture.  Here is the water vapor loop
NOAA GOES_Composite Water Vapor Loop 645 EST
The system in OK will transfer its energy to a new low pressure center off the SE coast tomorrow.  That storm will continue to deepen as it moves South and East of New England.

Light snow breaks out overnight tonight.  Warm moist Atlantic air will flow over the top of the cold Arctic air mass in place.  As a result snow forms well ahead of the actual storm.  The morning commute will be slow due to the light snow.  Here is the national simulated radar for 8 am

22z HRRR CONUS Simulated Radar (image weatherbell)
I don't expect it to snow all morning or afternoon, but that does not mean the forecast is a bust.  Check out the precipitation train that is coming.  The evening commute will also be slow but shouldn't be impossible.  The heavy snow will work back in around 8-9 PM.
18z NAM hires CONUS Simulated Radar (image weatherbell)
Winds will generally gust 20-40 mph in Southeastern New England although stronger gusts are likely over the Cape and Islands.  Friday morning the snow will wrap up so expect a miserable AM commute.

Miserable day tomorrow.  South of the Pike, East of 495 will be in the 20's tomorrow.  Everyone else is around 10-15
18z NAM hires 2 m temp 12 PM Thur (image weatherbell)
This is nasty cold.  Tomorrow night we approach 0
18z NAM hires 2 m temps 7 am Fri (image weatherbell)
Wind chills are well below 0.  If you have to be outside just be smart and dress it layers.  Be careful with the kids playing in the snow.  The snow will be fluffy and it will be blowing and drifting.

I'll update as needed.


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