Rain Marching Closer
Mild March weather will stick around through Wednesday then slightly below average temperatures will be common the second half of the week through the upcoming weekend. The next two days will not match the warmth of a year ago when we enjoyed two consecutive high temperature records. It reached 71 degrees on both March 12 and March 13! I see three potential precipitation events from now to the beginning of spring on the 20th.
With the aid of some spells of filtered sunshine today, it warmed up to 50-55 degrees in many locations away from south-facing coastal areas. A ridge of high pressure has shifted offshore and the resultant southerly breeze is escorting mild air into the region. It will remain mild all night with temperatures failing to fall below 40 in most spots. There is a slight risk of some areas of fog late tonight into tomorrow morning. Now despite the lack of bright sunshine tomorrow, the temperatures will rise up to the lower to middle 50s except 40s at south-facing coastal areas as a southerly wind freshens to 12-28 mph. A frontal boundary currently pressing across the Ohio Valley will arrive tomorrow night. It will be preceded by a ribbon of rain which will arrive in western New England tomorrow morning then advance to the coastal plain by 3-4pm. There could be some spotty precursor showers but the solid rain shield holds off until the homebound commute. There will likely be some patches of moderate to heavy rain in this parcel of precipitation amounting to 0.5 to 1.0″ of rain. WIth the rain and the melting snow, the National Weather Service has posted a FLOOD WATCH for late tomorrow afternoon into early Wednesday morning. The flooding risk is focused mainly on small streams and poor drainage street flooding only. The strip of wet weather will pass offshore after midnight with clearing swooping in behind. It should be partly to mostly clear for the morning commute on Wednesday with a wakeup reading just under 40 degrees. Sunshine will yield to some instability clouds especially during the afternoon when it will be near 50 degrees in the Boston area. As a trough of low pressure and secondary frontal boundary approach from the northwest later in the day, there is slight risk of a sprinkle or light shower mainly over the hills to the northwest. Unstable air will lead to some more puffy clouds and perhaps a snow shower or sprinkle in spots on Thursday as colder air rushes in from Canada. The wind will be brisk and gusty and highs in the lower 40s will do it. Friday will still be breezy with a partly sunny sky and similar temperatures.
Looking ahead, a clipper quickly sailing southeastward from the Great Lakes area will provide sufficient moisture and lift for some rain perhaps mixing with and changing to snow if the intensity is great enough Saturday afternoon and evening. A few inches of snow cannot be ruled out at this time for areas mainly north and west of Boston. Once this feature exits, breezy and drier weather will follow on Sunday with lots of sunshine and highs again in the lower 40s. On Monday, sunshine will yield to increasing high cloudiness streaming out ahead of a developing storm in the Midwest. It is too premature to be confident about the outcome right now but signs suggest a deepening cyclone somewhere in the Northeast. There could be a primary center of low pressure tracking from Ohio into western NY while a secondary storm blossoms on the NJ coast and heads northeastward to southeastern New England. The specifics are fuzzy currently so we’ll have to wait for subsequent forecast cycles at the end of this week or over the weekend to be more certain of the details. Some parts of the region COULD get another slug of snow from the last hours of winter on the 19th into the first hours of spring on the 20th. We shall see.
Joe Joyce will post his latest thoughts on the WBZ AccuWeather Forecast for Melissa Mack in the morning and I shall follow later in the day for Todd Gutner.
Make it a good Tuesday!