DAYS 1-5 (MAY 25-29)
The meteorological process today takes me a little deeper into deciphering the mystery that is predicting the future, and now 2 of the 3 days that comprise Memorial Day Weekend will be in this DAYS 1-5 forecast period. Recalling recent tremendous disagreement among major medium range guidance, the process started with acknowledging that both solutions were likely overdone, and that reality likely lies somewhere between solutions. Since then, there’s been a little more agreement developing between the various models, although they are not quite “there” yet. But this leads me to further investigation based on what I know of model bias as it relates to the current and upcoming weather pattern.What I am confident of is that today will be a fairly nice day as high pressure, albeit weak, governs our weather. Coolest air will again be felt along the coast – typical for this spring set-up. High pressure shifts offshore tonight and Thursday and a warm front quietly goes by, with Thursday daytime featuring a varying amount of clouds but also some sunshine, mild to warm air, but still dry in terms of humidity. It is on Friday and Saturday when we will see the humidity spike up, but with the approach of a trough of low pressure and a surface low pressure area and frontal system, our chance of wet weather will go up too. The current idea is that the shower threat during the daytime hours of Friday will be mostly to the west of the WHW forecast area, but expand into the region at night, and then Saturday is the day that is likely to at least start with occasional showery weather. If we manage to get a wave of low pressure that sits to our south, as some guidance has suggested, we could end up with an onshore flow and a general overcast with drizzle and showers that persists more of the day. Some guidance pushes the system offshore a little more steadily and allows for drying to take place later on in the day, and I am cautiously optimistically leaning toward this scenario, but not completely losing the shower threat. In fact, I think there will still be enough influence from low pressure that we can see a pop up shower on Sunday too, but that the day overall will feature improvement over Saturday with a little more sunshine and lower humidity. With the importance of the forecast for this unofficial start of the summer season upcoming, I’ll continues to monitor and make any forecast adjustments needed, but for now this is how it looks.
TODAY: More sun than clouds. Highs 65-72, coolest coast. Wind variable teo SE up to 10 MPH.
TONIGHT: Variably cloudy. Lows 50-57. Wind SE under 10 MPH.
THURSDAY: Partly sunny. Highs 67-74. Wind SE-S 5-15 MPH.
THURSDAY NIGHT: Mostly cloudy. Lows 58-65. Wind S 5-15 MPH.
FRIDAY: Mostly cloudy. Chance of showers, favoring western areas late in the day. More humid – dewpoint cracking 60. Highs 66-73 coast, 73-80 inland. Wind S 10-20 MPH.
FRIDAY NIGHT: Mostly cloudy. Chance of showers, possibly a thunderstorm. Patchy fog. Humid. Lows 58-65. Wind S to variable up to 10 MPH.
SATURDAY: Mostly cloudy. Chance of showers. Areas of fog and drizzle. Humid – dew point 60+. Highs 65-72, cooler coast. Wind variable up to 10 MPH, may become E.
SATURDAY NIGHT: Clouds break, but fog patches remain. Humidity lowers. Lows 55-62. Wind variable to S up to 10 MPH.
SUNDAY: Cloud/sun mix. A pop up shower possible. Highs 68-75, coolest near the coast. Wind SE up to 10 MPH.
DAYS 6-10 (MAY 30 – JUNE 3)
If things follow the scenario I expect, then Memorial Day Monday would be a fair weather day with warmer inland temperatures but a cooler coastal sea breeze. After that building high pressure offshore could provide a taste of summer heat again for the final day of May. After that there are signs that high pressure drops down from eastern Canada with fair and somewhat cooler weather to start June, but a warm-up by late in the period as the high settles to the south. Obviously days 6-10 leave a fair amount of uncertainty on the table. As we wrap up meteorological spring, barring a heavier rainfall than forecast for the end of this week, we are going to end the March through May period in the top 10 as far as dry weather goes. Meteorological spring’s driest occurred in 1915 with only 3.50 inches of rain for Boston, with 1910, 1981, and 1927 coming in at #’s 2, 3, and 4, with 4.49 inches, 4.93 inches, and 4.95 inches, respectively. (Info from NWS via WBZ Meteorologist Eric Fisher.) At 5.84 inches of rain for March, April, and May-to-date, Boston sits at 8th driest with just a handful of days left to go.
DAYS 11-15 (JUNE 4-8)
A weak blocking pattern may try to establish itself but the overall weather pattern remains on the dry side with no extremes of temperature.