A Rainy Memorial Day

As we reach the end of May we can take a look back at what we have seen so far this month for weather. It has been a wild month overall with temperatures both well below average to well above average each week.

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To start the month we had a week of well below average temperatures in the low 50s and upper 40s, thanks to an upper air omega block, which then transitioned east over us by the second week bringing us above average temperatures and dry conditions. Even with all of the rain we saw the first week of the month, we still are well below average for precipitation.

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Tomorrow we see some of the remnants from now Tropical Depression Bonnie impact the region. 055124W_NL_sm.gif

Bonnie was downgraded from a Tropical Storm this morning as it impacted the coast of South Carolina and will continue to weaken as it travels into North Carolina over the next few days. The precipitation shield extends well to the north of the storm, so we will be in for a soaker for most of the day tomorrow for Memorial Day. Make sure to pack those umbrellas and raincoats as you will need them for any cookouts or services you may be attending. Here is a look at one model’s output for precipitation by the afternoon.gfs_apcpn_neus_5.png

This gives most areas in Western and Central MA between .5″-1.25″ and most of Eastern MA sees between .25″-.5″. There will be periods of locally heavy downpours and gusty winds as these are remnants of a Tropical Storm, so be on the lookout for that. Other than the rain, it will be a warm and muggy day with Highs in the low to mid 70s.

Thanks for reading and have a great Memorial Day! Be sure to remember all those who have lost their lives to fight for our safety!

It May still be April in New England

The start to Spring this year has been a crazy one thanks to the late shot of winter we saw in March and April. So far we have seen a little bit of everything in May from an end of winter chill the first week to a return to summer the second. Let’s take a quick look at what we have seen so far this month in the image below.

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So far we have been overall well below the average high temperature for the month with 10 of the 15 days having seen temps below the average high for that day. We saw this trend break for awhile last week with above average high temps, but it has quickly returned to below average for the beginning of this week.

As we discussed in our last blog post, the omega block(pictured below) was what brought us the cold weather for the beginning of the month.2016May04-Fig1We were on the cold side of this which caused us to see temperatures well below the average for this time of the year. This degraded by the end of that weekend and we were able to get into a warmer pattern last week which allowed us to see high temps back into the 70s for the week. This type of pattern is what is usually seen during the end of winter in March and April with cold temperatures and large amounts of precipitation. Although looking at the almanac, we see that we are actually still below average for the month in terms of precipitation.

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gfs_z500_vort_us_15.pngLooking ahead for the week, we do not see any big warmups until the weekend. Temperatures should be around average in the upper 60s to low 70s for the week as the flow turns more zonal. Monday is going to be the coolest day with Highs still in the 50s, but the week looks to remain rain free!\

Dreary May Weather in New England This Week

Spring in New England can be beautiful, but often it’s dreary.  When the jet stream pattern resembles the capital Greek letter Omega (Ω), centered over the middle of the U.S., the weather in New England will be cold and damp.  This pattern is called an “Omega Block”.

This is what is happening this week.  The jet stream, shown in the figure below, as of 2 am, Wednesday morning, May 4th, already has this shape.  Once this pattern sets up, it usually lasts for days, and the current forecast is for that to happen this week.

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This pattern causes New England weather to be controlled by the upper level low pressure area sitting southwest of our region.  The resulting weather tends to be cloudy and damp, with periods of rain caused by weak upper level disturbances that rotate around the upper level low pressure area, which shows up very clearly in the forecast for Friday morning, shown in the figure below.  Notice too how the jet stream is split into two parts.

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The figure below shows what the forecast for the jet stream is for Saturday morning, May 7th.  The southern part of the jet stream still looks somewhat like the letter Omega.

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The current forecast (as of Wednesday morning) shows the Omega Block beginning to dissipate on Saturday, although New England remains under the influence of a cold, upper level low pressure area.  We will have to put up with clouds and showers right through the weekend, and hope for better weather later next week.