Weekly Discussion 6/12-6/18

Hot, hazy, and humid weather will continue through Tuesday.  Some showers and thunderstorms are probable Tuesday afternoon as a cold front crosses the region.  This front will drop temperatures to seasonable levels on Wednesday and Thursday.  A storm system on Friday will bring breezy Southeast winds, rain, and below average temperatures.   The Bermuda High will return this weekend setting a clash of air masses just to our west.  Interior and Northern New England will likely see showers and thunderstorms but the front will weaken as it reaches the Atlantic.

Monday

High pressure in the SW Atlantic will keep temperatures elevated and will gradually contribute to higher dew points.  Skies will be mainly sunny and max temperatures will rise into the mid 90’s. The MA DEP has issued an *Air Quality Alert* for sensitive groups today due to the presence of ozone today.

NWS Boston AM Headlines

SW winds gusting 25-30 MPH along the South Coast will force a sea breeze inland after 3 PM today.  Before that, temperatures will be in the upper 80’s even across the Cape and Islands (Nantucket a little less).

 

WPC Surface Fronts & Precipitation Monday 2 PM

Dew points this afternoon will be in the low to mid 60’s.  Starting this evening these T (DP) (dew point temperature) will rise into the upper 60’s.  Minimum temperatures tonight will only drop into the low 70’s.

Tuesday

A cold front will approach from the Northwest tomorrow afternoon.  Skies will begin the day mostly sunny before clouds thicken with the arrival of the front.   Temperatures pre-FROPA (frontal passage) will reach the upper 80’s and low 90’s.    T(DP) will be in the upper 60’s and low 70’s tomorrow so another Air Quality Alert will be issued.  Winds will gust 25-35 in the higher elevations of Western New England and 15-25 in NE CT, RI, and Eastern and Central MA.

 

NWS Max Temperatures Tuesday (image Weatherbell)

Most of the computer models meteorologists use for guidance are underwhelmed with the thunderstorm threat.  Some favorable parameters are in place such as a warm, humid air mass and an approaching cold front.   However, you need everything to come together for a big severe weather outbreak in Southern New England.  Wind shear (change of direction with height through a column in the atmosphere) will be relatively weak and so will atmospheric lift.  We need the lift to generate the towering cumulonimbus clouds way up into the atmosphere.  Some regular summer-time thunderstorms will heavy rain, lightning, and gusty winds will be possible between 1-5 PM tomorrow.

 

WPC Surface Fronts/Precipitation Tuesday 8 PM

Minimum temperatures will fall into the low to mid 60’s overnight Tuesday into Wednesday.

Wednesday-Thursday

Mostly sunny skies are expected on Wednesday as Canadian high pressure takes over for the Bermuda high.  Max temperatures will reach the upper 70’s for most.  T(DP) will fall into the upper 40’s and low 50’s.   Northerly winds will be 5-10 MPH with gusts up to 15 MPH.

 

WPC Surface Fronts/Precipitation Wednesday 8 AM

A few high clouds will move overhead Wednesday night.  Minimum temperatures Wednesday night will fall into the upper 40′ s and low 50’s which is 5-10 degrees below normal for mid-June.   Thursday will be similar to Wednesday with a bit more cloud cover.  Expect partly cloudy skies and temperatures in the low to mid 70’s.  Winds will gust out of the S 15-20 MPH Thursday late afternoon.  Winds will die down Thursday evening and temperatures will fall into the low 50’s.

Friday-Sunday

The big weather maker across the US this week is a storm system that is currently in Utah and moving NE into Wyoming, Colorado, Montana, Nebraska, and the Dakota’s.  Severe weather, including tornadoes, will move across the Northern tier over the next several days.  By the time it gets close enough to New England to impact our weather, the Bermuda high will begin to re-establish herself, slowing the storm system down.

WPC Surface Fronts Friday 8 AM

While some thunderstorms will be possible across interior New England on Friday, winds from the ESE off the Atlantic will really make it tough for strong storms to develop.  That won’t stop precipitation as it will arrive in Western and Northern New England late Friday AM.  Rain arrives in C/EMass/RI early Friday afternoon.  Temperatures will be in the mid to upper 60’s.  Rain continues early Friday evening but ends overnight.

 

NWS Max Temperatures Friday (image Weatherbell)

The ridge in the Atlantic will continue to strengthen this weekend.  That makes for a challenging forecast across interior New England.  The storm system to our west wants to continue east, but the building ridge will block it’s desired path.  Showers and thunderstorms will erupt each day in between the two systems.   On Saturday this should be well to our west along the shores of the Great Lakes.  On Sunday this will be closer, in the Hudson River Valley and probably Northern New England as well.

Saturday looks seasonably cool with temperatures in the upper 60’s and low 70’s with lots of low clouds thanks to flow off the Atlantic. Sunday is forecast to be warmer with temperatures in the upper 70’s and low 80’s.     Around 1″ of rain is forecast over the next 7 days, with isolated higher amounts.  Northern MA and Southern VT, NH will have the potential to see a little more than that thanks to the Friday rain.

 

WPC 7 day precipitation forecast (image Weatherbell)

The weekend outlook will be posted Wednesday with much more on this forecast.

 

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