STRENGTHENING STORM INFUSED WITH TROPICAL MOISTURE AND ENERGY HEADS NORTH...SLOW IMPROVEMENT OVER THE WEEKEND
Welcome to the weather blog - a regular Monday through Friday discussion of the weather! While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants. I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible. You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is email@example.com. This blog is for you, so I hope you enjoy it! -Matt Noyes
General Weather Summary:
**SATURDAY UPDATE: A blown forecast Friday night for many areas...just want to take a moment to acknowledge that...I know that must have led to frustration with plans, etc., as the rain shield was sitting just miles offshore for several hours and both the rain and wind were found in that band. I sat eating dinner outside on a patio where I was forecasting torrential rain and wind gusts to 30 mph, watching the black storm clouds roll on by over the Eastern horizon just offshore. This certainly is good news with regard to flooding for some areas, though as radar indicates, heavy pockets of rain persist today and this will result in localized flooding in especially Northern New England. After this stumble, the forecast should now be back on track.
Of more importance is that the first Tropical Depression of the Atlantic Season, located over the Gulf of Mexico, is forecasted to pass close to New England by the middle of this upcoming week as Tropical Storm Alberto. A full analysis will come on Monday here on my website, but feel free to access the National Hurricane Center website for official information here: National Hurricane Center Link. -Matt**
Reminder: We continue to run the Help Your Neighbor Flood Help webpage. If you have a free or discounted service to offer flood victims, email firstname.lastname@example.org with the offer and we will add it to the collection at the Flood Help site: http://necn.wordpress.com.
Breaks of sunshine in some areas Friday will give hope of better weather times ahead, and though a few days of drier and sunnier weather remains in the offing, a vigorous rain and potentially strong wind maker lay between the current and the future.
The setup features a break in the action across New England Friday morning between the storm of the past couple of days - which brought flood problems first to Southeastern and Eastern Massachusetts, and then to Southern Maine - drifting over the Canadian border and weakening as it leaves northeastern Maine, and a new storm developing off the Mid-Atlantic coastline. This new storm will take center-stage from late Friday afternoon into Saturday, and from south to north.
The break in the action for a good chunk of Friday will be welcomed by many - with dry air nosing in high in the sky, this will erode the clouds above a few thousand feet, and will mean even the stubborn low-altitude gray clouds will break from time to time for some sunshine in Central and Southern New England. Where sunshine breaks through, temperatures will respond nicely and the first 2/3 of Friday will actually be a very nice day compared to what we've seen recently! Farther north, Northern New England will find clouds locked in through the day, and resultant cool conditions continuing. Meanwhile, enough moisture will linger in the lower levels of the atmosphere for us all to run the risk of a scattered shower passing through our community and winds will be light through most of the day as they gradually shift from southwest to southeast.
By late afternoon and evening, all eyes will be turning to a shield of rain moving northward into New England off the Atlantic Ocean, associated with a strengthening storm center that was located off Virginia Beach as of this writing. I have been expressing a few concerns with this storm in my discussions and broadcasts the past couple of days, focused around the fact that the storm center is developing in tropical air over the Western Atlantic. As soon as it came off the coastline, the center of the storm was well defined on radar, and has continued to hold its definition while feeding off of moisture bands from both the north and south of the storm center. This deep tropical moisture infusion will mean extremely heavy rain will be carried with the storm, and this rainfall will spread over New England from south to north later Friday afternoon through Friday evening, and lasting through Friday night. Over four inches of rain will fall in less than 12 hours in some parts of Eastern New England (see map at top of discussion for rainfall forecast) and this will reaggravate flooding in recently flooding areas, bringing a return of street flooding, ponding of water in low-lying areas, stream and small river flooding Friday night and then into Saturday as the rain runs off into our small and medium sized rivers of Eastern New England.
Rain won't be the only concern of the storm, however, as the strengthening storm that developed in the tropical air off the Mid-Atlantic coast will develop a core of wind around its center - primarily on the east side of the circulation. That makes the exact track of the storm Friday evening and night critical to the wind and precipitation forecast. As of this writing, it still seems most likely that the storm center will pass over Buzzard's Bay Friday evening or the first part of Friday night, and this would put most of Cape Cod into a brief period of gusty winds that may gust over 45 mph from the southeast. The remainder of extreme eastern New England may see gusts to over 30 mph until the storm backs into the coast of Maine, spreading the higher winds back onto the coastline (see wind forecast maps above). Winds of this nature normally wouldn't be much concern, but with such soft, muddy, water-logged ground, trees can be uprooted with this kind of wind resulting in scattered power outages, and mariners may want to consider throwing on an extra line or an extra fender in preparation for the potential wind.
Expect the heavy rains to shift north by Saturday morning, and that's where rain will linger through the day Saturday - across Northern New England, with localized flooding still a possibility through most of the day. In Southern New England, runoff from the overnight rains will still cause streams and rivers to rise during the day, though the intensity of the rain will decrease early to lingering showers with some breaks of sunshine possible during the afternoon and an active westerly wind.
On Sunday, the entire storm will become large and sluggish, and this means we're still likely to find plenty of showers and even periods of rain in the North Country, though I'm hopeful for a blend of sun and clouds with scattered showers in Central New England, and a mostly dry day with just a few light showers possible during the afternoon.
Monday and Tuesday will bring nicer weather for all of New England.
Matt's Technical Meteorological Discussion: Updated Friday, June 9 at 1:30 PM
Dynamic situation complicated by tropical infusion underway. Most of details discussed yesterday as to potential low level warm core characteristics so let's bring each other up to date. Shortwave induced sfc low development in the overnight hours which had good radar presentation to center of circulation as soon as it emerged off NC coast. Radar presentation remained good until system was outside of range. Since then, visible sat imagery shows center of circulation still present and expect it to re-emerge on radar imagery this afternoon. Key to forecast is storm track and "extratropical transition". Of course, I put the latter in quotes because we're not dealing with a totally tropical system but warm core in the low levels and that means winds will remain compact around the center until sfc core goes cold. Latest 12Z models are allowing this transition to occur as system approaches NewEng's south coastal waters but this is likely too soon and will maintain going wind fcst on east side of system. As for storm track, believe over Buzzard's Bay still looks accurate based on 500 mb flow ahead of tremendously sharp trough and with s/w energy feeding in from SW flank of sfc system, and this lines up well with GFS fcst not to mention sfc frontal boundary draped over Ern NewEng, which is evident in shift from SE to S/SW winds over Boston Metro West, and will be nudged eastward - remember this front for QPF. As for wind, will not be long period of winds and not amazingly intense, but 45-60 mph gusts on a saturated ground would be enuf to down trees by uprooting. Also have urged marine community to be sure vessels are secure with xtra fenders. Again, I realize wind fcst is above guidance but that is because I am expecting consolidated wind field thanks to llvl tropical nature. Have gone much above guidance for QPF but tropical airmass is one factor that will push amount higher and other is the frontal boundry mentioned above as this will only help to maximize precip production so we should easily exceed 4" and some may exceed 6" in Eastern NewEng. These rains shift into Nrn NewEng Fri overnight and linger Sat.
Otherwise, fcst pretty straight-forward tho interesting to note convection continues off Central America coastline and current pattern would favor any tropical system that does develop being carried up Eastern Seaboard in time with tropical connection not only evident to a meteorologist examining guidance but also to any individual examining a satellite image. Would love to remark on this some more and will look at it in future discussion - maybe later today, but more likely not until Monday. We'll see.