Thursday Forecast

2:14AM

DAYS 1-5 (MARCH 1-5)
A cold front passed through the region overnight with a few light rain showers. This was not a sharp boundary with lots of cold air behind it so today will still be a mild day as clouds increase ahead of the developing major storm system set to impact the region from later tonight through Friday, with lingering effects into the weekend. There has been uncertainty in the details of the storm track, as in how close it will be to the New England South Coast as it does a loop then heads off to the southeast in response to a rapidly developing blocking high pressure area over Greenland to eastern Canada. The large scale has been a fairly easy forecast but its the minute details that result in forecast difficulties. What I do know is that the just-beyond-full-moon high tide cycles midday Friday, late Friday night, and midday Saturday are going to result in moderate to major flooding on east-facing and north-facing coasts, and minor to moderate flooding elsewhere. Property damage is likely as a result of the moderate to major flooding. Strong east to northeast winds are also a certainty, of course strongest in coastal areas and higher elevations as is typical. This may result in damage as well. A large percentage of the storm’s precipitation will likely be in the form of rain due to a marginal atmosphere I expect to be just warm enough to keep it mainly rain. Some flooding will result as a few bands of heavy rain may move over the same areas for several hours. The wildcard is snowfall. With the atmosphere marginal, the combination of colder air aloft and heavy precipitation can change rain to wet snow, and this can occur in a patchy fashion and not a more uniform rain/snow line. This is a very difficult aspect of the storm to forecast as just differences of a couple degrees can mean the difference between no snow, a few inches of snow, and a much larger snowfall accumulation. Going to play the lower side on the snow for now, keeping in mind that this can change very rapidly and updates will come if necessary. The forecast will reflect a mix/change from late Friday afternoon into Friday night before the storm pulls its heaviest precipitation southward and out of the region. The odds favor accumulation in higher elevations of central MA and southwestern NH, and also possibly over higher elevations of northern RI and nearby MA. Will keep the forecast numbers conservative for these areas at this point and allow for a minor accumulation at the end of the storm elsewhere. By the weekend and Monday, this storm will have evolved into a very large circulation as it heads southeastward toward Bermuda, and southeastern New England will remain under the influence of it with some lingering coastal flooding, gusty wind, and a few rain/snow showers, especially Saturday, diminishing thereafter. Forecast details…
TODAY: Increasing clouds. Highs 52-60. Wind NW up to 10 MPH.
TONIGHT: Cloudy. Rain arriving overnight. Lows 38-45. Wind N to NE increasing to 10-20 MPH with higher gusts.
FRIDAY: Overcast. Rain, heavy at times, may mix with or turn to snow higher elevations central MA and southwestern NH late in the day. Temperatures steady 38-45 much of day then falling slowly late. Wind E 15-35 MPH with gusts 45-55 MPH interior, 25-40 MPH with gusts 50-70 MPH coast, strongest Cape Cod. Coastal flooding especially near high tide times. Road flooding possible due to heavy rain. Probable wind damage and scattered power outages.
FRIDAY NIGHT: Overcast. Mix/snow higher elevations central MA and southwestern NH, rain may end as mix/snow elsewhere. Early-call accumulation 1-4 inches higher elevations central MA and southwestern NH and possibly northern RI and nearby MA, less than 1 inch elsewhere. Precipitation tapering off north to south. Lows 32-39. Wind NE 15-35 MPH with higher gusts. Moderate to major coastal flooding around high tide times.
SATURDAY: Mostly cloudy. Passing rain/snow showers. Highs 38-45. Wind NE to N 15-30 MPH with higher gusts. Coastal flooding around high tide times, especially north-facing shores.
SUNDAY: Partly sunny. Windy. Lows from the lower to middle 30s. Highs from the upper 30s to middle 40s.
MONDAY: Partly cloudy. Breezy. Lows from the lower to middle 30s. Highs from the upper 30s to middle 40s.

DAYS 6-10 (MARCH 6-10)
Blocking pattern continues. Next storm threat favoring late March 6 to early March 9 and may include some snow/mix.

DAYS 11-15 (MARCH 11-15)
Blocking pattern continues. One more storm threat possible favoring the middle of this period.