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 and a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. My email is contact@mattnoyes.net. This blog is for you, so I hope you enjoy it! -Matt Noyes
For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net
Matt's Quick Weather Synopsis: Spring officially begins Monday afternoon at 1:26 PM - welcome to a new season! Though the calendar now marks the change, nature has yet to catch up, and Monday will bring a blend of sun and clouds, but temperatures holding only in the 30's and winds gusting from the northwest up to 30 mph, adding an extra chill through the day. A few very narrow bands of snow showers are resulting in a few slick spots Monday morning, and a few flurries will crop up Monday afternoon, particularly in the hilly and mountainous terrain. You can always follow the latest radar data from my main homepage, linked above. Overnight Monday Night expect mainly clear and cold conditions except in the Northern Mountains where scattered flurries will fall. By Tuesday, a strong and moisture-laden storm across the nation's midsection will head for the Eastern Seaboard. While snow will fall with this system as far north as the Mid-Atlantic Tuesday night, right now it still appears as though this heavy precipitation producer stays south of New England, as we remain under the influence of a large swirling storm in the upper levels of the atmosphere just north of New England. The net result is for sunshine to fade behind increasing clouds Tuesday afternoon with an active breeze and temperatures nearly 10 degrees warmer than they were on Monday. With the upper level storm to our north shifting over us for the latter half of the week, Wednesday and Thursday should be mostly cloudy and cool with scattered flurries and snow showers, with clouds breaking for some sunshine by later Friday. Have a great start to your workweek! -Matt
General Weather Summary: It seems with regard to the weather that we pick up this week where we left off last week - with an upper level storm swirling just north of New England and slowly migrating southward to a position directly over the six-state region over the course of this week. This will make it very difficult for nature to respond to our man-made calendar call of Spring 2006, which officially begins Monday at 1:26 PM, as our cooler-than-normal pattern remains locked in through the week, and - on average - through the beginning of April.
In the meantime, the influence of the persistent upper level storm to our north is keeping a broad area of surface low pressure spinning to our northeast, as well, and this will maintain an active wind from the northwest across New England, with gusts up to 30 mph. These brisk winds will continue feeding cold air southward out of Canada, battling the effects of strong mid-March sunshine and holding temperatures in the 30's for most communities Monday afternoon. While most of the day will be dry - dry enough for high to very high fire danger across Central and Southern New England Monday Afternoon - morning snow showers were found in scattered locales, and a few mountain flurries are possible this afternoon. The relatively dry and cool flow of air from the northwest will mean a continued high fire danger threat - some red flag warnings have been issued by the National Weather Service for parts of Southern New England and can be found through my main webpage by clicking on the link for "current watches, warnings and advisories" - so caution should be used with any and all fires, and even with things like cigarette butts. This dry and cool air will, however, bring a mainly clear and chilly Monday Overnight with a few flurries found only in the mountains.
By Tuesday, attention turns to a storm that's been cranking up across the Western and Central United States this weekend. This storm has brought flooding rains to Eastern Texas and will continue to spread flooding rains and severe weather across the Southeastern United States, while dropping heavy snows on the northern side of the storm circulation, across the Central Plains and Midwestern United States. This energetic storm will spin east with copious amounts of moisture, but it appears as though the upper level storm centered over New England will continue to keep our steering flow over the Northeast from the northwest, and this means it would be very difficult to bring a storm northward into our region. Instead, as the strong storm center moves east off the Mid-Atlantic and Southeast coastline Tuesday night into Wednesday, New England remains under the influence of the stubborn northern upper level storm. The result will be increasing clouds later Tuesday, then a steady pattern of mostly cloudy skies and scattered flurries with cool conditions Wednesday, Thursday and Friday morning. As the strong storm to our south moves east over the Western Atlantic, a weak disturbance in the atmosphere will join our stubborn northern storm to the departing ocean system. This disturbance is known as an "inverted trough" in the world of meteorology, because it extends from southeast to northwest, and may help to focus heavier snow showers and squalls through the mountains of Maine and Downeast coastline late Wednesday and Wednesday evening, though this interaction is delicate and it's too early to speak with certainty on this enhancement. Regardless, the cold upper level storm will slowly begin to deteriorate on Friday, and this should allow for clouds to break for increasing sunshine Friday afternoon, and temperatures will respond to this sunshine, coming into the middle and perhaps upper 40's.
I'd like to see a bit more in the way of dry and bright parameters in our guidance before I promise improvement for Saturday - at this point, it certainly appears as though the upper level storm continues to break down and depart, and high pressure - a fair weather center - nudges east out of Southern Canada and toward New England. The problem here is that a departing low to our northeast and incoming high from the west can establish a northeast flow of wind at the surface, and it's possible a northeast wind would still carry clouds and cool air into New England on Saturday. This will become more clear over the next couple of days, when I can ascertain just how moist any air brought our way on a northeast wind would be. By Sunday, a more northerly wind would dominate, which is still a cool direction but not as likely to bring clouds in.
In the longer range, I expect an average pattern of below-normal-temperatures to continue through the first half of April! Remember, though, that "normal" temperatures continue to rise as the days wear on, so even below normal temperatures will still bring gradual warming. Nonetheless, even as the pattern shifts from deep cold to more shallow cold air domes by the beginning of April, the weather pattern will bring repeated areas of high pressure to the Canadian Maritimes, which means New England will remain quite vulnerable to strong "backdoor cold fronts" for the first half of April, which are cold fronts that come in from the northeast, rather than the normal direction from the west or northwest. The result of these types of fronts is often low altitude grey clouds and a cool flow off of chilly ocean waters. While this appears as though it may be the way we begin April, the Western United States and Western Canada will build significant warmth during the same time period, and once the pattern breaks - perhaps by the third week of April - that would open the door to a significant and sudden warmup. Remember...temperatures into the 80's aren't unheard of for later in April, so while the immediate future looks cool, there is plenty of hope for a warmup later in the game.
Have a great Monday!
Matt
Matt's Technical Meteorological Discussion: Updated Monday, March 20 at 12:25 PM
It's the upper low that won't let go! This thing is getting ridiculous, but we'll roll with the punches. The storm you and I have been watching together in this discussion for literally weeks is now underway across the Central and Southern Plains, and will continue to pack a wallop as it heads east toward the coastline, carrying heavy snows on the north side of the circulation thru the OH Valley and severe weather/flooding to the Southeastern US. With deep NW flow in place here in NewEng, however, it's unlikely we'll see any measurable precip from the Southern sys making it this far north - this weekend featured one cycle of the NAM that brought accumulating snow to SE NewEng Wed, which certainly made my eyes light up given how long we've been watching this storm, but that was just about the only twinkle of hope to get any precip this far north. More on this below.
In the short range, excellent deep mixing will bring winds from 860-880 mb down to the surface in gusts, but considering winds at that level are only 25-30 kts, I don't expect surface gusts to exceed these numbers. Still, windy enuf and dry enuf for high to very high fire danger across NewEng. No brushfires nearby on Sunday, and usually nearby fires are a precursor to activity here, but with the combo of mixing and dry air, any fires could grow quickly, so extreme caution should be used for most of Central and Southern NewEng. Still, low-level convergence, low to mid-level instability and upslope flow helped to generate isolated bands of snow showers Mon AM and these isolated bands of precip resulted in slippery conditions on a few roadways and major highways in SW CT leading to accidents. Diurnal mixing will keep this phenomenon from persisting thru the day, tho hilly and mountainous terrain and associated upslope flow will result in flurries. Mon Ngt winds will subside but not entirely and it's unlikely that many areas aside from deepest valleys of Northern NewEng will decouple. Still, with dewpoints in the single digits, it won't be tough to fall into the teens.
As the upper low settles south over NewEng on Tue, expect clouds to fill in with increasing instability during the afternoon with stratocumulus deck filling in after sunshine to start. 925 mb temps rebound significantly from Mon to Tue - from -9C to -2C on average - and this will equate to about a 9 F degree increase in sfc high temps when increased late cloud cover is accounted for. This increased moisture and instability marks the beginning of what should be a period of about 60+ hours of broken stratocumulus under the upper low, lasting thru Fri AM before the upper low degrades, fills, and warms aloft, allowing for increased sun.
As mentioned at the beginning of this discussion, it certainly appears as tho the Southern stream system will remain south of NewEng. Wavers are still being exhibited in a few operational model runs - even the 12Z NAM and GFS of today are coming a bit farther north with 700 mb moisture, and this is largely due to uncertainty/inconsistencies in handling the interaction between southern stream moisture and northern stream trough axis which begins W to E oriented and slowly pivots around the vortex center and ejects shortwaves ahead of it, each of which will provide a northerly tug on the moisture field. While this could pull 500 and 700 mb moisture to the South Coast and Ci and Ac clouds, we'd have a long way to go to get the deeper precipitating moisture that far north, and with confluent and WSW flow aloft, it's an even tough trip north to make. The end result is that this is likely to be largely a miss for NewEng, and goes into the log books as a great job keying in on storm potential from weeks out - there's no question this thing is a doozie - but just not a cooperative enough pattern to get this puppy north, owing entirely to the stubborn upper low. Note, however, I say the storm largely is a miss for NewEng, not entirely. The distinction comes in Downeast ME where inverted trough takes on potential Norlun characteristics and should provide focus for enhanced snow showers or periods of snow in Eastern ME on Wed. NAM is doing a good job picking up on this and we should continue to monitor this potential for at least lightly accumulating snow in Eastern ME.
Thereafter, although the trough technically is still bridged from underneath the upper low all the way east to the ocean low southeast of Nova Scotia by Thursday morning, there is little if any interaction between the two systems by that point. Still, the surface trough under the upper low will have decent low level convergence and is accompanied by -30 C air at 500 mb, and this combination should be able to carry snow showers southward thru the ME Coast and into Southern NewEng by Thursday. Temps thru the period should run well below MOS guidance thanks to cloud cover and anomalously cold flow keeping us well below the climatology-weighted computer generated statistical products.
As mentioned already, Fri features a filling of the upper low and this should bring improving conditions, esp Fri afternoon. I'm not convinced the tricky forecasting is done then, however, even though high pressure builds in from the west, because a bubble of this high pressure extends over extreme Eastern Canada and low pressure strengthens to our south. The result, therefore, is for a northeast surface wind to take hold through most of NewEng, and we are not only coming into the time of year for backdoor fronts, but also a very favorable pattern with confluent flow shifting just northeast of NewEng - a good place to lock cool air in. So, I am concerned about a northeast flow locking in low altitude clouds and cold for Saturday, then by Sunday while it's possible winds come more northerly behind the strengthening ocean storm that develops south of NewEng, strong signals are for an inverted trough extending well north-northwest of the storm center toward Southern NewEng, which not only keeps us on guard for precip, but more importantly make reinforce a northeast wind on the cold side of the trough. It's obviously still a long way out - and I've seen situations like this where you're advecting in 10 degree dewpoint air on a northeast wind, so while it's cool it's not moist enough for clouds, but I'm not convinced that's the case here with the modified air that was under the upper low all week, and my concern is there for cloudy and gross weather for the weekend. Will go easy on that potential from this far out and the variables of wind direction and relative humidity so important in this setup, but certainly feel it's well within reason to forecast a cool weekend.
Speaking of cool, Ensemble solutions continue to support what we've been thinking together in these discussions - a cool pattern through the first two weeks of April as troughing persists, and with confluent flow repeatedly showing up just east of NewEng, repeated strong backdoor fronts thru the second week of April that will help to ensure a colder than normal pattern prevails. Meanwhile, warmth and ridging that was over Greenland for so long will slowly retrograde across Canada and then merge with a building ridge over the Western US. It's my gut feeling that the Ensemble forecasts of 8 C above normal at 850 mb over the Western US for the end of the first week of April are underdone - perhaps significantly - and that the first 14 days of April will result in some significant heat building over the Western US. If that happens, then once the pattern of repeated backdoors and NE US troffing subsides...likely after the second week of April...this could mean a quick and rather substantial warmup for the northeast. I have very little guidance - OK, none - to go off of for the last two weeks of April, but the jet stream configuration, once it snaps here in the Northeast, should allow enough warm air to stream northeast that we may be looking at one of those end-of-April runs where we jump into some very summerlike air. I can certainly remember plenty of 80+ days in late April, and it usually comes from a pattern like this. Something to watch, anyway.
In the meantime, we have plenty of other obstacles to get past so we'll keep our eyes open.
Enjoy your Monday.
Matt
