Potentially Dangerous Storm- 1/23/17-1/25/17- Discussion

Good evening from Southern Connecticut Weather!
​
   You could classify today as the proverbial "calm before the storm". Across the state today, we had a brief period of sun before the clouds moved in. Conditions stayed dry today and will continue to do so through early this evening. Temperatures stayed steady in the mid 40s to lower 50s at the shore. Heading through this evening, temperatures will drop back into the 30s statewide, lower to mid 30s inland, with mid and upper 30s at the shore. I see chances for showers building throughout the evening as our next weather maker begins to make itself felt. Along with precip chances increasing, winds will be on the increase as well. This evening should be fine as you make your last minute storm preparations in coastal Connecticut. Then we move onto early Monday morning...

Synopsis: We have a very potent and complex weather system moving in from the southwest bringing along with it heavy rain, winds, periods of snow and sleet in northern areas, and possible coastal flooding.

Timing: Starting Monday morning through Tuesday evening, height of the storm would be Monday afternoon through early Tuesday morning, with precipitation continuing through late Tuesday night.

​Main impacts: High winds, heavy rains, coastal flooding, extended periods of snow and sleet well away from the shore and north of I84.

Technical discussion: There is a potent shortwave system moving in from the southwest which will greatly strengthen over the next few days. Usually storms that strengthen to this magnitude tend to track far to the west while the entire state is enveloped in a "warm sector" with temperatures rocketing into the 50s and 60s in some cases, with rain. In this case, we have 2 things preventing this storm from tracking in such a way. First, we have a high pressure block in central Canada prevented this storm from riding way up into the Great Lakes region and also a well placed high pressure area just north of main. So the storm will track just off Delmarva Peninsula then most likely over Cape Cod. Now you noticed in the timing how impacts will be felt from Monday morning through Wednesday morning, a rather long duration storm for this area, that's another function of the "block" in central Canada, it is preventing the storm from escaping and scooting out to sea. Which is bad news for most of us, especially on the shoreline. 

​   While the storm moves very slowly, and the storm remains very strong and still strengthens while in the Atlantic. The state, especially the shore, will be pounded with quite strong winds for a long period of time. This will not only extending the likelihood of wind damage, but cause a risk for coastal flooding as these strong east winds pile up water into Long Island Sound. Timing for this flooding to occur would be throughout the storm from Monday afternoon through Tuesday morning, when winds do look to subside a bit. Across the state, there are various wind related warnings and advisories. Along the immediate Connecticut shore, there is a high wind warning in place where sustained winds are expected to be 30-40 mph with gusts to 70 mph, in this area, extreme caution should be exercised. The northern portions of the coastal counties are under wind advisories for sustained winds 25-35 mph with gusts to 55 mph, this advisory is also in effect for Litchfield county as well. Hartford, Tolland and Windham counties do not have any wind related advisories issued, but that does not mean to let your guard down, wind gusts could mix down from the mid-levels of the atmosphere at any time, I'd still expect some wind gusts to exceed 45 mph. Still enough to cause issues with power. Timing for these wind advisories extend from 1 am Monday to 1 am Tuesday, but expect gusty winds to last well into Tuesday as well.

​   So you see that I haven't mentioned that 's' word yet. Impacts from snow look to be quite minimal from this system, and confined to far northern Connecticut. I could see a solid 1-3 inches of snow falling in portions of the Litchfield hills. You are probably saying to yourself, potent system tracking to our south, shouldn't there be more of a snow threat? Well, no. Right now we are in more of a mid-March pattern than a mid to late January pattern in terms of temps. Surface temperatures throughout the system will remain basically mid 30s to around 40, with temps in the 850 and 925 levels (or mid levels) hovering right around freezing to just below. Even with a storm of this magnitude making it's cold air, we would need some very heavy areas of precip to form, promoting dynamic cooling to get even the slightest bit of frozen precipitation to the ground. That said, I do see there being an extended period of heavy sleet or snow from Monday afternoon through Monday evening as the storm really gets going in these parts, I feel all frozen should have changed to rain by daybreak on Tuesday and continue as rain, statewide, through the day on Tuesday. As the storm pulls away and winds begin to blow out of the northwest, I do think some areas away from the shore could change briefly to snow or a mix. The bigger issue with this storm, as far as precipitation goes, will be pouring rain. I'm expecting on the order of 1-2 inches of rain statewide, at times, the rains could be quite heavy so please take caution if you need to travel over the next few days and watch for ponding on the roadways.

   I cannot stress enough how dangerous this storm can be for the state of Connecticut, especially the shoreline. Just because this isn't going to be a nor'easter with extreme snows does not mean you shouldn't be prepared. Make sure you have all of your essentials ready, flashlights, generators, non-perishables, etc in case the lights go out in your home. On the shoreline, this could essentially be 24 hours of tropical storm conditions with gusts approaching hurricane strength. The conditional coastal flooding threat is nothing to be joked about either. On the flip side, don't freak out, stay calm, most of us are seasoned vets when it comes to strong coastal storms, just doesn't hurt to be prepared, is all.

So to recap...
-Storm starts to impact area early Monday morning and goes through late Tuesday

-Winds will gradually pick up through this evening, and will peak on Monday afternoon and evening. Sustained winds of 30-40 mph for the shore, and 20-30 mph for the rest of the state with along Gusts along the coast approaching  70+ mph. The rest of the state could see gusts up to 55 mph.

-Sleet and snow threat for areas north of I84, 1-3 inches snow/sleet NW hills

-Coastal flooding looks to be an issue from Monday through Tuesday

-Heavy rain expected from Monday through Tuesday

​-We clear out for the day on Wednesday

​Have a great evening everyone! We will be with you right through the storm. Keep it locked to Southern Connecticut Weather for all of the latest updates.- TW

Follow @SouthernCTWX