Currently: The surface warm front that brought showers to the state today is now well north of the state, extending from the thumb of Michigan, then eastward along the US-Canada border. However, this warm front has now gone stationary, meaning that its northward movement has stopped. Two low pressure systems are along a cold front- one low is near Chicago and another low near the TX/OK border. These complex systems will begin to affect our weather, starting tomorrow afternoon.
Tonight: With lots of clouds around and the state being in the warm sector, do not expect temperatures to drop much, or have much difference from one place to the other tonight. In general, temperatures will be within a few degrees of 40 for lows, with a couple upper 30s possible over the NW hills and sheltered valleys in the north.
Tomorrow: With today’s warm front returning as a backdoor cold front, expect rain to move in from the north from the morning to the afternoon. Up north, the front will clear the area, so expect rain to only last a few hours and then end. In the south, generally anywhere south of I-84, expect light rain and drizzle to continue all night once it gets started. As far as temperatures tomorrow, this will also be tricky both due to timing the frontal passage and onset of rain, but also dealing with any potential sea breeze boundaries. I will tenuously go with fairly uniform highs in the lower 50s, and try not to worry about the tiny little boundaries that could set up tomorrow, but this is a low-confidence forecast.
Tomorrow Night/Sunday: Across the north, it is very probable that no precipitation will fall until Sunday afternoon, with the approach of the Midwest low. Across the rest of the state, periods of mainly light rain and drizzle are likely, transitioning to a more steady rain as the day Sunday goes on. Sunday will be quite chilly, as the entire state will be north of the backdoor frontal boundary. Expect high temperatures to be in the 40 to 45 degree range. It should be noted that the north will have warmer high temperatures, due to the fact that it will likely not be raining there.
Long Term: Nothing lasts forever, even cold April rain? Well, we’ll see! Most days through the long term period should feature rain. The best days of the long term period will likely be Wednesday and Thursday.
Monday could very well feature a period of heavy rain during the day, morning SW and afternoon NE, as the backdoor front, with the aid of the Midwestern low, will spread a slug of heavy rain into the area. For now, I am going with a model blend for temperatures on Monday, with highs expected to be around 50 degrees. It will not surprise me, however, if this forecast ends up being too warm, since models tend to drive warm fronts through too fast.
On Tuesday, the warm front will probably be through the area, if we believe the models, and we’ll wait for the cold front to go through. Showers will be possible at any time on Tuesday, but especially during the afternoon, and perhaps another round of sprinkles late at night along the actual cold front. It is not totally out of the realm of possibility for a bolt of lightning or rumble of thunder Tuesday afternoon, but due to very low probability, I am leaving it out of the forecast for now.
Wednesday and Thursday should feature fair weather, albeit with a gusty wind at times, as the cold front will finally clear the rain out of the area, as cold fronts do. Wednesday should see highs in the upper 50s, with maybe a 60 degree reading in the CT valley, and Thursday should see highs of 50-55.
The next storm system, a coastal low, will threaten the state Friday. There is more uncertainty with this system, as some of the models show the storm heading a bit too far to the south to really affect the state and only give us a glancing blow, while other models give the state a full-on nor’easter. There is also a very low probability of this turning into a winter storm if it can deepen and take a favorable track, since there is a good high pressure system to the north. However, that probability is very low given the time of year, and would be more probable for the northern areas. Just something to watch. At any rate, Friday looks to see another possible bout of unsettled weather.
The long range does not look much different. A parade of storm systems affecting the state every 2 or 3 days with not many breaks in between, looks to be the theme until further notice. At least we’re drought busting.
Hydrology: Despite the fact that most of the state, especially up north, still has snow and ice on the ground, hydrologic concerns should be fairly low, considering the fact that we are in a drought, and the rain falls over a long period of time. But small stream and poor drainage nuisance flooding will be possible, especially Monday.
Now, let's take a look at some of the systems slated to affect our area in graphical format. First, here is the rain from the back door cold front. This map is from Saturday afternoon. you can see the entire state is in light rain. North of the Massachusetts Turnpike, the rain is ending, and that is pushing south.