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John Homenuk

5.13 PM Zones: Cool and unsettled now, big warmup looms

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Good evening! It has been a dreary, rainy, damp Saturday as a low pressure system developed off the coast of New Jersey. A storm which has been discussed for several days certainly lived up to its billing. Gradually improving weather is anticipated later this afternoon and into this evening, but improving is a word that will be used lightly, as drizzly and damp weather is expected to persist despite the heavy rain ending.

As Sunday approaches, the overall weather is expected to improve in the Mid Atlantic states. While coastal New England will still be feeling the effects of a low pressure system developing in the Gulf of Maine, areas further southwest will see more sunshine — which could fuel the development of a few storms capable of producing small hail and gusty winds.

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Steven Copertino

FREE Public Analysis: Damp and Dreary Conditions Gives Way to Above-Normal Temps

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Good Afternoon and Happy Friday!

The low pressure that moved just west of our area yesterday has slowly continued on towards the north and east this afternoon, bringing yet another gloomy and day. This low will gradually lift out into eastern Canada by Saturday, but stout northwesterly winds will keep temperatures somewhat below-normal throughout the day. By Sunday, some relief from this cool and gloomy weather should arrive as an area of high pressure builds in from the southwest. As this high locks itself offshore during the beginning of next week, we may see temperatures well-above average for this time of year. The question is, does this warm period last, or is it just a passing tease?

This Afternoon and Evening 

As mentioned, the very energetic area of low pressure that produced heavy rainfall, intense lightning, and even some damaging wind gusts for portions of the New York metro area has lifted into Canada this afternoon, leaving behind much cooler temperatures in its wake. Temperatures have struggled to get out of the mid-upper 40’s this afternoon, which is a good four to six degrees (c) for this time of year. When coupled with wind gusts in the 20-30 mph range, this makes temperatures feel even worse, dropping down into the upper 30’s and low 40’s. These windy conditions are due to the strong area of low pressure exiting to the north east of our area, producing a tight pressure gradient over the region as it presses against a high pressure system currently located over the Mississippi Valley.

Showers have been relatively persistent this afternoon across the area, providing some light rain or drizzle to really put the icing on the miserable conditions of this afternoon. As the last piece of energy associated with Thursday storm swings through, these showers and a weak cold front may bring some more showers towards sunset, with the possibility of a mix of snow and rain in the more inland/elevated locations. These rain or mix showers are expected to be very light in nature and no significant precipitation is expected to fall from these showers as support for their development gradually wanes this afternoon.

Mostly cloudy conditions should persist throughout the rest of the afternoon as the weak front and associated upper level energy wring out the last bit of moisture available in the atmosphere. Once we head into this evening, the remaining showers should die off and skies should gradually clear, leaving temperatures rather cold for this time of year. Most locations should see lows this evening range from the mid 30’s, to low 40’s closer to the coast.

Current surface temperatures, regional radar mosaic, and visible satellite imagery showing relatively cold and damp conditions this afternoon (Courtesy of GREarth)

Current surface temperatures, regional radar mosaic, and visible satellite imagery showing relatively cold and damp conditions this afternoon (Courtesy of GREarth)

Saturday and Sunday

As we work our way into Saturday morning, temperatures should be relatively cool to start off the day with 30’s and low 40’s being commonplace across the area. As high pressure begins to establish itself on Saturday afternoon, winds from the northwest will keep things dry, but also relatively cool. Temperatures should be in the low to upper 50’s across the area under mostly sunny skies, however the pressure gradient that was mentioned earlier will still be lingering over the region, so winds of 15-20 mph may make things feel a bit more chilly than they actually are. Overall, Saturday should be an improvement from the past few days, but will ultimately be a few degrees below normal in the end. Saturday evening should feature clear skies with temperatures in the mid 40’s, with upper 30’s possible to the north and west of New York City.

As the high pressure system begins to move to our south on Sunday morning, winds will begin to shift to the south/southwest with somewhat chilly conditions to start off with. As the morning progresses,  these southwesterly winds will usher in much warmer conditions by Sunday afternoon. Temperatures should have no problem reaching into the 60’s on Sunday afternoon with clear skies and light southerly winds. This will make Sunday the highlight of the weekend, but this is only the beginning of the above-normal temperature regime!

3km NAM showing temperatures reaching at or around 60 degrees areawide on Sunday afternoon (Valid 2pm)

3km NAM showing temperatures reaching at or around 60 degrees areawide on Sunday afternoon (Valid 2pm)

Extended Range (Monday-Friday)

With the area of high pressure centered off of the Mid-Atlantic coast on Monday, warmer temperatures will continue to build throughout the week with increasing, deep southwesterly flow at the surface. This will allow temperatures to reach all the way up into the mid 70’s and possibly even low 80’s for southern locations on Monday and Tuesday. If such temperatures are realized early on in the work week, these would easily be around 12-15 degrees above normal for this time of year, which would be a remarkable contrast to this week’s dreary deluges.

In addition to this period of much warmer weather, conditions should also be much less active for now, as the storm track across the country leads the low pressure track well off to our west.

Temperatures should remain a good 8-15 degrees above normal each day through Thursday afternoon, before a potential disturbance from Canada drops down and brings in a chance at some more unsettled weather and cooler temperatures.

After this period of more calm and dry conditions, the Pacific looks to become much more active once again, so we will have to watch for more stormy conditions on the horizon as multiple systems line up to impact the western US and possibly travel east.

12z GFS upper level winds at 300mb showing a very active potential pattern shaping up over the Pacific, similar to the one that recently provided the severe weather and heavy rains (Valid 8am Thursday)

12z GFS upper level winds at 300mb showing a very active potential pattern shaping up over the Pacific, similar to the one that recently provided the severe weather and heavy rains (Valid 8am Thursday)

With some impressive warmth and a potentially more active pattern returning in the long-range, make sure to stay tuned for updates!

For more information and posts like this one, make sure you sign up for Zone Forecasts — where multiple detailed articles, videos, and interactives are posted each day. Also, come interact with our staff and many other weather enthusiasts at 33andrain.com!

Have a great weekend!

Steve Copertino

Steven Copertino

Public Analysis: Cold Front Passage, Big Warmup This Weekend

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The general theme of the winter of 2016-2017 continues this week.

Due to a lack of blocking that would normally work to slow individual pieces of energy within the jetstream down, we have once again missed out on a sizeable storm for the Northeast. As you can see down below, we have two separate pieces of energy that were quite literally just 12-18 hours away from being able to interact with one another and produce a snowstorm for the Northeast US. The computer models were in excellent agreement over the past five days that instead, these two pieces would not be able to interact in time due to the very quick flow, and would instead come together this evening to produce a low pressure system that will track to the east of the 40N/70W benchmark while rapidly strengthening and deliver sizeable snows to southern New England and portions of Maine.

500mb map highlighting the two disturbances that were able to remain just far enough apart to prevent another snowstorm for our area (Valid 4am this morning)

500mb map highlighting the two disturbances that were able to remain just far enough apart to prevent another snowstorm for our area (Valid 4am this morning)

Even though we miss out on a large storm, the northern piece of energy moving over our area today is quite vigorous and will be accompanied by a strong cold front. This cold front was located in central Pennsylvania as of 1pm this afternoon with numerous showers noted across the region. In conjunction with the strong mid level disturbance, we have strong low-level lapse rates, which are basically the change in temperature within an area from the surface to a few thousand feet above our heads. When there is a healthy difference in temperatures with increasing height, we see upward motion take place in the atmosphere which promotes shower development like we are seeing ahead, as well as behind this cold front. This afternoons short range computer models have been keying in on these showers and the associated cold front impacting the NYC region by 3pm or so.  The entire region should expect showers lasting through the evening commute, but due to the factors mentioned above, it would not be impossible for the northern sections of the area to see some graupel or even snow mixed in with these showers as the front passes and temperatures begin to drop. Those traveling should pay attention for possibly slick road conditions in the heavier rain/snow showers this afternoon and evening. As the precipitation moves out later this evening, expect gusty winds on the order of 25-35 mph from the WNW to take over and last into tomorrow due to yet another tight pressure gradient over the area associated with the strong low exiting to our east.

Current surface map showing the location of the cold front and associated showers set to move over the region this afternoon (Courtesy of Simuawips.com)

Current surface map showing the location of the cold front and associated showers set to move over the region this afternoon (Courtesy of Simuawips.com)

With temperatures this afternoon in the 30’s to middle and upper 40’s across the area, the cold front passage later today should provide a good contrast as temps fall into the low 30’s and into the 20’s for inland sections this evening. Thursday and Friday will feature a more seasonable airmass in place with highs in the middle to upper 30’s across the entire region with mostly dry weather expected for both days. As we move into the weekend, a broad area of mid level ridging will move in from the west and continue east over our area. Winds from the south/southwest will send temperatures well-above normal on both Saturday and Sunday with highs deep into the 50’s across the area. Some southern locations may possibly sneak into the 60’s by Sunday afternoon if stronger southwest winds are realized. Due to the aforementioned ridging, conditions should remain dry with mostly clear skies, so this weekend should be an excellent one to enjoy the warmer weather before things turn a bit cooler and unsettled into the work week next week.

Afternoon European model showing temperatures on Sunday possibly reaching 18-24 degrees above normal (Centered on 1pm Sunday)

Afternoon European model showing temperatures on Sunday possibly reaching 18-24 degrees above normal (Centered on 1pm Sunday)

For more information and posts like this one, make sure you sign up for Zone Forecasts — where multiple detailed articles, videos, and interactives are posted each day.

Have a great day!

 

John Homenuk

Premium: Warmer than normal temperatures by late May

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The news many have awaited for several weeks is finally here: We are forecasting the return of above average temperatures by the end of May. For the past few weeks, the hemispheric pattern has been stuck in a bit of a rut. High latitude blocking has maintained its control over the pattern, on both the Pacific and the Atlantic sides, forcing the development of anomalous cutoff lows and troughs into the Northern 1/3 of the United States. Colder than normal air with unsettled weather has been the dominant sensible weather in our area.

The transition out of this pattern is already underway. While high latitude blocking on the Pacific side (a -EPO) will again flex its muscles late this week, it will be more of a parting shot than anything else. An upper level low will form, as a response to the -EPO ridging, and push into the Great Lakes. But its presence will be mainly progressive, as a front swings through our area and the upper level trough elongates and moves to our northeast.

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