Supermoon, Coastal Flooding, Perseid Meteor Shower & a Worsening Drought

LKS_DROUGHTMONITOR (1) LKS_DROUGHTMONITOR (1) LKS_DROUGHTMONITOR (1) LKS_DROUGHTMONITOR (1) LKS_DROUGHTMONITOR (1) LKS_DROUGHTMONITOR (1)The weekly Drought Monitor update rolled in Thursday morning and recent thunderstorms simply haven’t been enough to stop the slide for Eastern MA and Southern RI, now upgraded from Severe Drought to Extreme Drought from the government/university consortium that issues the national assessment.  We did see some improvement in Northern New England, with much of the Upper Valley and Mountains actually sliding out of drought thanks to recent thunderstorms with torrential downpours.  Although very limited rain will fall in parts of New England Thursday, it won’t be impactful on the drought – amounts will be quite light, on the order of a tenth of an inch or less, even in the spots that see steadiest rain.  Lots of clouds during the day drop rain showers from the Boston Metro to Southeast CT points southeast, wrapping up from west to east, early afternoon to early evening, northwest to southeast.  Farther northwest, scattered showers in Northern New England Thursday won’t creep into Central New England, or Central to Western MA and CT, where the day should stay dry.  Thursday night brings the full Sturgeon Moon to New England, rising just after 8 PM, officially reaching full just after 9:30 PM and the final “Supermoon” of the year, just a bit closer and a bit brighter than a typical full moon, and exerting just enough gravitational pull on Earth to deliver high enough tidal levels for some splash over and very minor coastal flooding in typically vulnerable spots at the near-midnight high tides Thursday and Friday nights.  Thinning Thursday evening clouds not only will make way for a view of the Supermoon, but also for glimpses of the Perseid Meteor Shower, set to peak Friday night but already visible with occasional meteors in our night sky.  As the night wears on, partly cloudy skies will eventually combine with pockets of dense fog in Eastern New England that will linger into Friday morning before thinning out.  Friday will feature more clouds than sun as a large area of upper level energy slowly gathers over the Northeast U.S., prompting scattered afternoon rain showers, particularly in Eastern New England, as high temperatures reach to around 80 degrees with a moderate amount of humidity.  New Englanders may want to get used to the feeling of the temperatures and humidity these next few days, seasonable for this time of the year but also where we’ll land for just about the entire First Alert 10-day forecast, with the chance of showers fluctuating as various upper atmospheric disturbances ripple through the jet stream winds aloft, parked over the Northeast next week and therefore raising the chance of showers on several days in the 10-day forecast, but particularly centered around midweek next week.

Cooling Air But Warming Ocean Water, Some Coastal Flooding Expected

LKS_SST_CURRENT LKS_SST_CURRENT LKS_SST_CURRENTThe heat and humidity have left New England, but that doesn’t mean the weather is quiet!  In fact, there will be some subtle but important features impacting New England weather in the days ahead, and much of this revolves around the ocean.  First, a northeast wind is delivering entirely new air to New England Wednesday, with afternoon high temperatures in the 70s to near 80 degrees and dew point temperatures – the measure of the amount of moisture in the air – down from sultry 70s to a much more comfortable level in the lower to middle 60s.  This more comfortable air should stick around, at least for the most part, through the majority of the exclusive First Alert 10-day forecast!  The most obvious result is the shift from deep summer heat to more seasonable temperatures, bringing an end to a record stretch: a record 26 consecutive days of 80° or warmer high temperatures, a record hot 31 day stretch and, so far this season, we’ve tied the record for most days at or above 98° with five (tying 1911 and 1944).  Yet, amid all the heat, Eastern MA and NH Seacoast residents have been asking since July 4th: why has ocean water been so chilly?  We covered that earlier in the season but it’s noteworthy again because…it’s about to change!  The majority of this season has featured a westerly wind, sweeping the milder skin of surface ocean water out to sea, where it’s been sitting over the Gulf of Maine.  Now that the wind has shifted to blow from the northeast, that will allow some of this milder ocean water to return back toward the shoreline and as of Wednesday morning we’ve already seen the buoy in Cape Cod Bay record a 5 degree, 24-hour water temperature jump and this should be felt at our eastern beaches in the coming days, a bit ironic since the air temperature is dropping enough that pools and lakes will cool pretty quickly, instead!  Another noteworthy point for our coasts is the third and final Supermoon of the year is coming at the end of this week, meaning tidal levels are high and minor coastal flooding is expected in typically vulnerable spots along New England’s shorelines at high tide Wednesday night, Thursday night and Friday night.  Meanwhile, the massive change in air, though complete at ground level, is still ongoing in the sky, which is why lots of clouds will continue to blot out the sun in the coming days, though particularly the afternoons will feature splashes of sun.  Wednesday morning showers tapered to only lingering sprinkles, but new showers are expected Thursday morning – especially in Southeast MA – scattered Thursday afternoon and perhaps one or two showers Friday and Saturday between breaks of sun and clouds. In fact, the next 10 days will feature a pattern that often will bring an elevated chance of showers as the jet stream – the fast river or air high in the sky – dips south from Canada into the Northeast U.S., providing frequent energetic disturbances and temperatures close to normal for this time of the year.

Tuesday Afternoon and Evening Thunder Ahead of New, Cooler Air

LKS_FIRSTALERT_MAP_NEWENG_ACTIVE (8)The long-awaited change of air is on New England’s doorstep, as a well-defined cold front separating the long-standing warmth and humidity in the Northeast from cooler and less humid air marching through Eastern Canada is poised to cross New England.  Ahead of the cold front, a few morning showers in Northern and Central New England didn’t amount to much, but as breaks of sun between clouds allow temperatures to rise into the 90s in the southern half of New England, the afternoon arrival of the cold front will mean scattered thunderstorms, increasing from midday through the afternoon and continuing through the evening.  The storms erupt as an indicator of an overturning air and, fueled by the abundant humidity with dew point temperatures in the 70s, will produce torrential rain at times along with frequent lightning, while some of the stronger storms will be capable of producing localized damaging gusts of wind.  As always, “when thunder roars, go indoors” – if you can hear thunder, the storm is close enough for lightning to be a danger.  Although flash flooding isn’t likely for most, it’s not impossible that the combination of heavy rain rates with a dry and hard ground resistant to absorbing water may lead to enough water in a short enough time to overwhelm drainage and result in spots of flooding.  Overnight Tuesday night the cold front will ease toward the South Coast and swing the wind to blow from the north and northeast, opening the flow of new, cooler and less humid air that will take hold of New England for days on end.  At first, the change in air isn’t a clean one through all levels of the sky, with some warmth and moisture still battling against the cool air aloft, resulting in times of clouds and a few showers Wednesday, and some pockets of showers Thursday, with both days reaching near 80 degrees as a high temperature.  A second, reinforcing shot of cooler, drier air arrives Thursday evening with one last round of showers before opening the pathway for delightful, pleasant air with a fair sky to take hold Friday through Sunday, and even into the start of next week!  By the middle of next week, warmth and humidity builds back enough for an increased chance of showers and thunder to re-enter the forecast, but not to the extremes we just experienced!

Heat and Humidity Will End in Storms Tuesday

LKS_NBCU_POP_D0_NEWENG (12) LKS_NBCU_POP_D0_NEWENG (12) LKS_NBCU_POP_D0_NEWENG (12)An end to the heat and humidity is in sight, but New England has a couple more days to go before we get there.  A well-defined frontal boundary separating cooler Canadian air from the heat and humidity in place across the eastern half of the United States is producing a well-defined line of showers and thunderstorms, which sags very slowly into New England Monday and Tuesday, opening the door to that Canadian air that will be firmly in place by midweek.  Some of New England is already seeing the change to cooler air – Northern ME finds rain on Monday and temperatures that will hover in the 60s throughout the day, and while the rest of Northern New England is still warm and humid, the slowly sagging front inching south will result in clusters of rain and thunder in the North Country Monday afternoon into night.  That same cold front will cross the remainder of New England Tuesday, increasing our cloud cover but also raising our chance for thunderstorms as the cooler air cuts into ample heat and humidity, with one more day Tuesday well into the 90s and pushing 100 degrees in a few spots, with thick, humid air producing a heat index over 100 degrees, yet again, for some Southern New England communities.  When scattered to widespread thunderstorms develop in Central and Southern New England, they’ll feed off the heat and humidity to produce torrential downpours, lightning and very likely some pockets of damaging wind during the afternoon to evening hours as the storms migrate from north to south across Central and Southern New England.  A brand new wind direction – from the north and northeast – will follow the passing cold front, supplying the new, cooler, less humid air that will take hold of New England through the end of the week.  Because the change is so dramatic – and doesn’t happen all at once through all levels of the atmosphere, with warmth and humidity holding on a bit longer aloft and continuing to battle back against the cool push – showers are likely to crop up both Wednesday and Thursday in New England, particularly Southern New England.  By Friday the chance of showers isn’t zero, but certainly begins decreasing as drier air takes hold at all levels of the atmosphere and that new air will ensure a delightful weekend, looking great with fair skies and feeling great with high temperatures in the 70s and 80s.  Warmth and humidity will slowly rebuild next week, but isn’t expected to reach the extreme levels of the past several days in our exclusive First Alert 10-day forecast.