Warm Weather on the Way

500 mb vorticity  map (mid level of atmosphere) shows cut off low in SW, trough exiting  NE

The unseasonably warm weather will continue into middle to late March.  After approaching 70 on Thursday we cooled down yesterday and today.  I was expecting a quick burst of snow yesterday but I did not expect 3-6 inches north of Boston.  Here you can see the totals from last nights snow event.  That is behind us now as the energy is moving offshore of Cape Cod.  High pressure will build into the region and the warming trend will begin.  We have to get through today first as temperatures will only reach 40 or so.  Temperatures tonight will drop into the upper 20's before climbing into the upper 50's tomorrow.  The south coast will be held to the upper 40's due to  a southerly wind off the water.

The energy in Arizona and New Mexico has cut off from the general flow.  This will slowly move northeastward toward the Great Lakes.  Areas in the path of this low will see some heavy rainfall over the next several days.  This will help pull warm air into the Northeast.  High pressure will move offshore locking in a Southwesterly flow and setting up some of the warmest March weather in the last 100-125 years (that is how long records go back in the Northeast).  The lack of snow cover across the United States is not cooling off these air masses as they move across the country so we have more potential for higher temperatures.  (Hat tip to Eric Fisher of The Weather Channel).

Sunday- Highs Upper 50's inland, upper 40's coast DRY
Monday- Highs middle to upper 60's DRY Some exceed 70
Tuesday- Highs middle 60's, clouds increasing Rain likely (from the cut off)
Wednesday-Highs upper 50's windy

This looks to continue for the foreseeable meteorological future...(~2 weeks).  Enjoy it while we have it.

Wintry Precip Overnight, Heavy Rain Tomorrow

National NWS radar image

A powerful storm system sweeping across the United States will impact New England overnight.  This is the same system responsible for producing 53 tornadoes (and counting) across the Ohio Valley and the Deep South.  The storm will be weaker but there will still be some impacts around the region.  First off, a Winter Weather Advisory has been issued by the National Weather Service in the areas shaded below.  Image courtesy of NOAA

WWA txt here

Areas south of the Mass Pike will see very little snow and mainly a mixture of rain and sleet.  A warm front is surging north which will turn all precip over to rain by 3 am in the lower elevations.  Higher elevations will also turn over by 6 am.  The roads will be slick overnight so be careful on your way home.   Saturday will be warm, with highs near 50.  There will be a chance of a thunderstorm with this system as it moves through.  There will be no severe weather or tornadoes, but it will not be surprising to hear a few rumbles of thunder.  Most of the rain will be gone by 3-5 PM and skies will begin to clear for tomorrow night.

NOAA rainfall forecast for next 24 hrs

Next week is half winter/half spring.  On Sunday, Monday, and Tuesday it will feel more like winter, especially Monday and Tuesday when high temperatures will only be in the 30's.  The sun will be out from time to time.  One will notice a dramatic difference from Tuesday to Wednesday.  A subtropical ridge is looking to build in the Southwest Atlantic and funnel warm spring like weather into the northeast.  Highs right now look to climb in the upper 50's-low 60's.    This is the extended range of the forecast, but things are looking good.  Remember, if the pattern of the last few months remains in place, the nice long stretches of good weather will get progressively warmer and warmer as the sun continues to trek northward. 

Storm Prediction Center daily storm reports (so far)

Finally, thoughts and prayers to all those affected by the tornadoes this week.  Spring time is the beginning of tornado season due to the mixing of warm tropical air with cold arctic air.  This is a tornado outbreak to remember and its going to continue into the night.  Let us hope no more lives will be lost and all warnings are heeded.   Here you can view damage from today's storms.

Snow Update

National Weather Service Snowfall amounts, click to enlarge

The snow began to fall mid morning and started to come down steadily early this afternoon.  So far about 4 inches have fallen in Northbridge.  The first wave of energy is winding down now and there will be a break in precipitation until midnight or so.  Then the second burst of snow will begin and it will make the morning commute tough.  The rain snow line is going to creep into Northern CT/RI and maybe up through Boston overnight.  I think sleet will mix in with snow south of Worcester to the MA/RI border.  This will keep our snow totals down.  Still, this rain snow line is going to create a sharp divide between 6+ inch amounts and 1-4 inch amounts.  Temperatures will be in the upper 20's tonight/low 30's tomorrow.

Radar as of 915 EDT 2/29/12

The second wave will  gradually wind down in the mid morning hours.  However then a final pulse of energy will push through and finish everyone off with light snow tomorrow afternoon.  Areas north of Boston will get  whacked tomorrow.  That area received very little snow with this first event.  The second wave, which will affect us overnight, has bundles of energy so someone is going to get a healthy dumping of snow from it.  Most guidance suggests the Merrimack Valley out towards Leominster/Fitchburg into southern NH.  I am expecting an additional 3-5 in Southern Worcester county by morning.

Water Vapor Image.  System 3 over Great Lakes. 

This is all over by 1 am Friday morning (many will end before then) but tomorrow night's commute will also be affected.  Be safe if travelling and give yourself extra time.   

Just as I finished this up I noticed a nice band moving into Central MA/RI...

Taunton radar image

Winter Weather for a Change

Current National Weather Service Alert Map

National Weather Service Winter Storm watch (blue) Winter Weather Advisory (purple)

A winter storm watch is issued when the potential for greater than 6 inches of snow/ice are possible in 24 hrs

After months of a dormant weather pattern winter finally returns tomorrow.  A series of waves will move across  New England from tomorrow afternoon through Thursday night.  This is a three part system that will likely drop the heaviest snows since the Halloween Weekend storm.  The first phase will begin tomorrow between 2 and 4 pm and this is all snow for most.  4-8 inches of snow are likely by 6 am Thursday.  This will be the majority of the accumulating snow for southern New England.  Sleet will likely mix in from time to time south of the Mass Pike.  

Thursday looks to be sloppy.  Temperatures will be slightly above freezing so rain, sleet, freezing rain and snow will all be falling from the sky at various times.  By mid afternoon on Thursday a third and final wave will pass by as it weakens.  This will draw in more cold air and flip everything back over to snow.  I currently think an additional 1-3 inches of snow will be possible.

Main Storm System in the Rockies; Smaller waves will precede system, nudge high pressure off shore

  

Projected radar image, NAM model WED 8 PM

1000-850 mean sea level pressure/6 hr precip 11 pm WED from NAM (good cold air damning  signature)

Thursday 5 PM 500 mb Vorticity (final leg of the system)

I'll try to stay updated through the facebook group as I will be out of the state for most of tomorrow.

Snow coming tonight, Saturday

North American Model, 1 pm Saturday- courtesy NCEP

A disturbance passing southeast of New England tonight will coat the region with up to 3 inches of snow.  Similar to the previous light snow events of the last week, the snow will commence between 8 and 10 and will be tapering off by 5 am.  The snow will be mainly light, but there could be a period of moderate snow around midnight.  The snow will stick to the roadways immediately so travel with caution tonight, it will be slick.  Tomorrow will be sunny, albeit  cold with a biting west wind.  This will set the stage for Saturday.

A piece of energy is going to break off of the storm system that impacted the Pacific Northwest yesterday and make its way all the way to the Atlantic coast.  This is not a nor'easter or a classic big winter storm, but the storm will become stronger as it reaches the open waters of the Atlantic, south of New England.  Most areas north of the Mass Pike will see a general 4-8 inches of snow.  South of the pike we should expect 3-6 inches with a chance of sleet mixing in as Saturday progresses.  The snow starts to fly around 11 am and will continue off/on into early Sunday morning.  This system is much trickier to forecast than the first system so further updates will be necessary.  We've seen systems like these explode and drop a foot of snow (December 13, 2007).  I'm NOT saying I expect that, as the data currently doesn't favor that type of snow growth over Southern New England.  What I am saying is that New England weather has a mind of its own.

More later

Extended Forecast

First off I hope everyone is enjoying there Thanksgiving weekend.  A very nice Saturday is shaping up across Southern New England.  High pressure is just off of the North Carolina coast and is responsible for the unseasonably warm November weather.  The run of above average weather will continue until the North Atlantic Oscillation reverts to its negative phase.  The University of Columbia has made some nice graphics illustrating the effects of the NAO.

NAO Positive Phase

When the NAO is positive, the pressure gradient between Greenland and the Azores Islands is greater so storms are stronger; the Pressure Gradient Force is on of the most important forces in Atmospheric Science.

NAO Negative Phase

In the Negative Phase Greenland warms up while the East Coast is prone to more snowy outbreaks.  These graphics are slightly outdated and slightly incorrect, but it captures the general idea of the NAO.

Check out Columbia's webpage here.

For virtually all of November the NAO has been positive and it looks like it will continue into early December.  The models are not great at pattern recognition; they often break down patterns too quickly.  They have been hinting at a flip to the negative phase, but this has yet to happen.  The longer the NAO is positive the warmer our weather will be.  Here is the Climate Prediction Center forecast through December 1 and beyond.  Given that the models wanted to change this pattern for several weeks now, I think winter is coming fast.

So with the big picture out of the way, time for the forecast.    Today's temperatures will soar into the lower 60's.  Tonight a backdoor cold front drops in from the Gulf of Maine and will increase the chances for fog in the area overnight.  The front will stall, then lift north as a warm front letting temperatures soar in the mid 60's tomorrow as well.  We may approach record values today and/or tomorrow.

Increasing cloud cover will allow for overnight lows to be in the upper 40's tomorrow evening.  Monday looks to be a decent day, there is a slight chance of a shower late in the day but it will be a mostly cloudy afternoon with highs near 60.  By Tuesday a system is going to lift out of the Southeast and head north.  It will pass to our west so there is no chance for snow but rain will approach by early evening.  The Northbridge-Nipmuc game looks to be ok, but the later playoff games may be impacted by rain.  A shift in the timing by 3 hours throws a wrench in this forecast so stay tuned.  Wednesday will start off as wet before drying and cooling down later in the afternoon.

The end of next week and the start of December looks to be average, with sunny skies and temperatures in the low 40's.  For the longer range here is my look for December...

These are from NOAA's Physical Science Division US Climate Division data maps.  While average temperatures across the analog years were in the 20-30 degree F range, that indicates to me a battle ground for rain and snow in the month.  Precipitation looks likely for December so it is going to be a battle to see if cold or warm wins out, especially in the Blackstone Valley.  Areas north of Worcester should be mainly snow.  

Thanksgiving Week Forecast & Discussion

A nice weekend is shaping up for everyone.  High pressure will keep conditions calm and dry into Tuesday.  Tuesday night is when things get interesting as a storm system will lift out of the Midwest and develop a surface low pressure system off the coast.  There are two different model camps right now.  The American GFS, SREF, and GEFS favor a west to east track and the system would be gone by Wednesday evening, albeit dropping heavy rain for the majority of the overnight and morning hours.  The EURO and the NAM are both slower and they result in a phasing of the north and south Jet Streams, giving the storm a north Southwest-Northeast track.  This would be later and I feel a greater chance of snow on the backside with this scenario. Its too early to make a call but there is a near certainty for heavy rain.  A track closer to the coast is expect because the North Atlantic Oscillation is in its positive phase, meaning low pressure is semi-stationary between Greenland and Iceland.  As a result the storm is blocked from taking the classic big snowstorm track.

Highs today will crawl into the low 50's, while tomorrow will feature partly cloudy skies and a high near 60.  Overnight tonight the temperature will fall to around 40 degrees and it will drop to about 36 degrees tomorrow night.   Monday is a typical November day as highs will only reach the upper 40's.  Monday Night Football will be chilly, with temperatures dropping into the mid 30's.  Fans will be protected by some cloud cover which will prevent radiation cooling.  Tuesday looks to be mostly cloudy with highs in the mid 40's.  More on the Thanksgiving Eve event as more data comes in.

Thanksgiving looks cold, but sunny.  At 10 am the temperatures will be in the upper 30's.  Stay hydrated!