The Coming 7-10 Days: Two Storm Threats, Spring Arriving

As expected, the winter season appears to be winding down, and my forecast last week of the snow events being over from here on out looks accurate on long range models.  There’s a chance some snow/sleet could mix in at the onset of a storm moving in Thursday night, but with temperatures above freezing for the entire region no significant impacts are expected.  This post I’m going to run through the two main storm threats I am watching, one Thursday night into Saturday morning and another Monday night into Tuesday of next week; each one will bring some minor impacts but I am not expecting anything major.  I am watching the latter of the two for potential impacts slightly larger than the one later this week, but neither one should be cause for much concern.  Overall, the weather is relatively tranquil now as we transition from our winter-weather pattern into a more spring-like pattern of severe potential.  There’s always the chance of large, strong Nor’ Easters this time of year, but I don’t see too many of those on the horizon.  Monday night into Tuesday could try and come close to that, but I’ll discuss that more in a little.

Tomorrow should be a relatively nice day, with temperatures approaching 60 and clouds increasing throughout the day.  However, temperatures drop quickly overnight into the low 40s and upper 30s overnight as overrunning precipitation approaches the area.  Some weather models are more defined with heavier precipitation, but both agree that enough cold air will be pooled in front of the overrunning precipitation that some sleet/snow could begin inland at the onset for an hour or so before we go to all rain.  Most weather models have the heaviest rain between 4 AM and 8 AM, though again there is some variance.  Then during the day on Friday light precipitation and drizzle will continue as a very strong inversion sets up; temperatures at the surface will generally be in the 30s but aloft at 850mb (around 5,000 feet) temperatures will approach 10 degrees Celsius.  Though this warm air occlusion can be common, it occurring to this magnitude at this time of year is rare.  In fact, surface temperatures may not even reach the seasonal LOW temperature for this time of year in areas.  Either way, temperatures should remain just on the higher side of freezing, so I don’t expect we deal with any freezing issues on Friday into Friday night as light precipitation continues.  I’ll keep an eye on future surface temperatures runs, but right now I just expected stagnant air and potential air quality issues with light rain/drizzle throughout the day Friday into Friday night.  Any precipitation then winds down into the day on Saturday with total rainfall amounts anywhere from .2-.5 inches varying across the region.  A large variance, but this is a small-scale event so exactly where heavier precipitation sets up tomorrow night will determine what part of that range we reach.  Regardless, even high-end estimates are low enough that there are no flood risks or real impacts from this storm other than cold weather and nuisance rain on Friday.

Clearing comes into the weekend with high temperatures in the mid 50s and low temperatures in the mid 30s or so.  Then we start tracking the next storm system that will move through Monday into Tuesday.  Like during winter, weather models generally agree on the overall pattern but can diverge on the specifics, but the agreement here seems fairly strong, hence why I’m going to go a little more in depth with this storm system.  During Sunday night into Monday a storm system will move out of the Gulf of Mexico and progress over Ohio and then into Canada.  This has been a fairly significant trend to the west, which is good as it may help spare Southwestern Connecticut the worst of the winds with the storm system.  Generally, when strengthening low pressure centers move just west of the area, we deal with strong southerly flow that results in stronger surface winds due to relatively less friction over the Long Island Sound (especially in convection, where strong downward motion can mix down very strong winds aloft).  Some models even indicate a very weak secondary low pressure center trying to form near the area as the storm moves through, again limiting winds.  In terms of real conditions, the end result of this should be a period of heavy rain Monday night and maybe some briefly gusty winds as the precipitation shield on the southeastern flank of this low pressure center moves through.  Again, no serious impacts, but any strengthening low pressure center moving there just bears a little watching to make sure there are no more serious impacts than a period of rain, so stay tuned in case anything changes there.

The bad news for Spring and Summer lovers is that after that low pressure center moves through it will be strong enough to usher in a brief period of (relatively) very cold air.  We’re not talking teens or anything here, but areas are likely to get below freezing as temperatures aloft at the 5,000 foot level could get below 10 degrees celsius.  A very strong April sun angle will help warm things up during the day, but Wednesday night could be quite chilly as radiative cooling takes over.  Wednesday and Wednesday night maybe into Thursday will thus be unseasonable chilly, but warm air looks to flood back into the region a little more Thursday night into Friday, so we should return closer to average temperatures very late next week.

That’s a brief summary of the weather over the next 10 days or so.  Nothing too impactful expected, but two periods of unsettled weather could potentially disrupt some outdoor plans, along with a cold shot late that could throw us back to thinking it is February or March.  I’ll continue watching all future weather disruptions across the region, so make sure to keep it here for the latest!  As always, the 5-day forecast will be updated daily, and we will soon be revising the “Winter Storm Update” to make it more relevant for the spring weather we are about to see.  SWCTweather will be here throughout the Spring and Summer when bad weather threatens the region, so make sure to stay tuned!

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