Southeast Ridge Builds, But Not For Long…

Good evening! 

 

Today was another relatively mild day with some decent mid-upper level cloud cover that faded throughout the day as a weak disturbance to our south quickly moved eastward. High pressure over central and eastern Canada remains in control of the weather over much of the northern tier of the United States and has prevented the northward progression of the weak disturbance over the southeast US. This same high pressure system has also ushered in a colder airmass into the mid levels of the atmosphere, with the surface temperatures lagging behind. This lag-time between the surface and mid levels has allowed highs today to reach into the lower to middle 40’s across much of the New York metro area, with some locations in southern NJ reaching into the upper 40’s. As the evening goes on, we should see clouds continue to decrease in earnest, with only a few high cirrus clouds sticking around through the night as dry air continues to sink into the Northeast. With the relatively clear conditions expected, a renewed source for cold air, and light winds, conditions this evening will become quite favorable for radiational cooling to occur over the entire Northeast. We should see lows drop a good 15-20 degrees, with readings getting into the middle to upper 20’s across most of the metro area. Low 20’s and possibly teens will also be acheiveable to the north and west of the city due to excellent radiational cooling conditions in the valleys of NY state.

Snapshot of todays weather across the Northeast with regional radar mosiac, surface observations, and 500-meter high-resolution visible satellite data from GOES 16. Note the sharp cutoff of cirrus clouds just to the south of NYC

Snapshot of todays weather across the Northeast with regional radar mosiac, surface observations, and 500-meter high-resolution visible satellite data from GOES 16. Note the sharp cutoff of cirrus clouds just to the south of NYC

Thursday Into the Holiday Weekend 

Thursday looks to start off rather cold and clear as high pressure to our north remains in control of the weather. Temperatures during the morning commute will likely start off in the middle to upper 20’s, but as the day goes on tomorrow we should see clear skies and light northerly winds result in highs heading into the lower to middle 30’s, with upper 30’s to lower 40’s possible across southern New Jersey. Downsloping winds will cause of good amount of subsidence over the region tomorrow, so expect generally dry and clear conditions for the vast majority of the day. As we head into the evening hours tomorrow, ridging ahead of a growing system out in the plains will cause heights to rise over the East, which should bring an increase in mid level moisture. Clouds should gradually increase as darkness falls tomorrow, likely becoming mostly cloudy as the night progresses. With the increase mid level heights will come a more stout southwesterly flow over the region, which will work to increase mid level temperatures. Despite a marked increase of about 5-10 degrees in the mid levels, the high pressure to our north will continue to pump colder surface air into the Northeast. This more-dense cold air should win out against any potential warm air intrusions Thursday night, so look for lows to range in the middle to upper 20’s once again, with warmer lows in the 30’s expected to the south and west.

By Friday morning, we should see a significant amount of energy in the desert southwest that should help to pump the much-talked-about “southeast ridge” over the southeast. Moisture will begin to stream in over the ridge on Friday and pool ahead of a slow-moving cold front over the Tennessee valley. Southwest flow will increase throughout the day on Friday, leading to increasing temperatures and a threat for showers during the day. It is important to note that some of the precipitation at the onset of this system may actually be in the form of sleet/freezing rain/snow across locations to the north and west of the city due to stubborn low level cold air trying to hold on. Depending on how much this cold holds on, we could see a period of a light wintry mix into the early afternoon which may cause for slippery travel conditions. Regardless, expect much of the day to be unsettled with cloudy conditions and a chance at showers. Highs will be slightly warmer over the area on Friday, with temperatures in the 40’s expected for much of the Northeast.

This afternoons NAM model showing the building mid level ridge over the central part of the country, followed by a large supply of Polar air developing over southern Canada.

This afternoons NAM model showing the building mid level ridge over the central part of the country, followed by a large supply of Polar air developing over southern Canada.

 

Holiday Weekend Outlook and Beyond! 

More rain steady rain is likely for Saturday and into Sunday before things clear out on Sunday morning. A large piece of Pacific energy will be carving out a trough in the central United States that will work to pick apart the southeast ridge. A polar airmass will then flow into the back end of this trough, which should create a tight gradient between the warmer SE ridge and the cold over the Plains. The models begin to differ late on Christmas eve when a low pressure may develop over the Tennessee valley. This afternoons European model has trended colder and more to the south and east with this low, and would bring a rather significant snowfall on Christmas day as the low rides the temperature gradient, then quickly strengthens. Some of the other model guidance places this initial temperature boundary a little farther south, which causes the bulk of the system to ride out to sea with little fanfare for the Northeast. While the details still need to be worked out quite a bit, condition’s on Christmas are looking to be colder than originally forecast with the potential of a wintry day across the Northeast. This will be looked at much closer on Friday when most of the model guidance will be in their more-reliable range.

By Tuesday, we should see the polar cold begin to bleed into the Northeast as a large high pressure system takes over much of the eastern US. This cold will be setting the stage for a potentially wintry end to 2017 as the medium range models are beginning to sniff out a potential system arriving on the west coast  by next Wednesday. There will be the potential for another Polar airmass to invade the country, with a massive high pressure system over much of southern Canada. This high pressure system over Canada would then lead to any potential system developing in the Plains states to ride generally east. This kind of track would allow precipitation to break out over a large portion of the country as moisture streams northward from the Gulf of Mexico. With Continental Polar air filtering into the Northeast, there would be a heightened threat for snow as we draw closer to the 12/27-12/31 time frame. We will also be keeping a very close eye on this period over the next couple of day and provide updates when they’re available.

 

This afternoons European Ensembles showing a potentially cold and active period coming in the next 10-15 days as mid level ridging increased over the Arctic regions.

This afternoons European Ensembles showing a potentially cold and active period coming in the next 10-15 days as mid level ridging increased over the Arctic regions.

Stay tuned for further public updates! . Also join us at 33andrain forums for free discussion on everything weather-related.

Have a great night!

 

Zonal Pattern Gives Way to More Extremes Across the Country

Good Evening! 

A weak area of mid level energy moved quickly through the Northeast last evening and into the early morning hours today, which had just enough kick left to it to bring  some isolated and relatively light areas of precipitation. Depending on your location, this precipitation varied from plain rain, freezing rain, or even some light snow. Any frozen precipitation accumulations were extremely light, but still made for a slick morning commute today. The quick-moving west to east flow that has become established over the majority of the country will be responsible for bringing some more weak mid-level energy over the region through the rest of the day, which has led to a rather dreary and  warmer day than the past couple of days. West/southwesterly flow has allowed mid level temperatures to rise over much of the Mid-Atlantic and Northeast, which has allowed surface temperatures to respond accordingly throughout the day. We have seen highs across much of the Northeast rise into the lower to middle 40’s across the majority of the area, with higher readings around the 50’s observed in portions of southern New Jersey. These mostly cloudy and slightly-above normal temperatures should continue into the evening hours, with a chance of some patchy fog across the area as some moisture may become trapped within a low level inversion.

Expect temperatures this evening to fall back into the upper 30’s and lower 40’s across the immediate NYC metro area, with cooler temperatures likely well to the north and west.

This evenings latest regional radar mosaic, GOES 13 visible satellite imagery, and surface observations showing a more mile and dreary end to the day across much of the Northeast

This evenings latest regional radar mosaic, GOES 13 visible satellite imagery, and surface observations showing a more mile and dreary end to the day across much of the Northeast

Tuesday Into Thursday 

A deep cyclone moving through portions of central and eastern Canada will continue to drag a rather stout southwesterly flow over the Northeast tomorrow afternoon, which should also bring in more dry air to clear out the low-mid levels of the atmosphere. This should allow for a vast majority of the clouds to dissipate as the day goes on tomorrow. This deep southwesterly flow and relatively clear skies across the area should allow temperatures to rise into the “well-above normal” territory as highs will likely get into the middle-upper 40’s-with some 50-degree readings possible. Thankfully, moisture will be quite limited across the east, so we expect a generally calm and mild day tomorrow for much of the Northeast. Later in the day, a cold front associated with the same cyclone in Canada will begin to creep into the Northeast. This front will work east through the area throughout the overnight hours, but will likely bring lows down into the upper 20’s to low 30’s just in time for the morning commute on Wednesday.

Wednesday  should be a much cooler day by contrast as northwesterly flow behind the cold front ushers in fresh, Canadian air. A vigorous little area of mid level energy will be opening up from its time as a closed upper level low and will begin to quickly head east across the southern half of the country. This strong west to east flow across the nation will ensure that this area of energy becomes sheared out, with all of its rain staying well to the south of the Northeast. In fact, conditions will remain very dry across the Northeast, and there may be a couple of strong post-frontal wind gusts in the early part of the day. The renewed northwesterly flow, clear skies, and dry air should allow temperatures to stay relatively cool across the majority of the region, with highs in the middle to upper 30’s likely. Locations to the north and west may in fact see highs stuck in the lower to middle 30’s as some deeper Canadian air becomes trapped. These calm and cooler conditions will last into the evening hours on Wednesday before another weak cold front begins to move into the east. This front will be severely moisture starved, but will be capable of reinforcing the cold air already in place. With dry low/mid levels, cold air aloft, and light northerly winds, conditions should be supportive of some radiational cooling to take place. This should bump lows down into the middle to upper 20’s , with upper teens to middle 20’s likely off to the north and west.

Thursday morning will see the reinforcement of colder air over the Northeast, with the morning commute likely starting off quite crisp in the 20’s. A mid-level ridge will begin to build over the Ohio Valley in response to an area of Pacific energy digging into the west coast, but conditions over much of the Northeast will likely remain quite cool and clear as high pressure begins to build and expand over southeastern Canada. This should lead to another pleasant day with highs mainly in the upper 30’s to lower 40’s. Mid level flow will begin to shift to the southwest during the evenings hours on Thursday, which will begin to set the stage for another above-normal period of temperatures.

Loop of this evenings NAM model showing a brief period of cooler temperatures over the Northeast, followed by another warm surge by the end of the week.

Loop of this evenings NAM model showing a brief period of cooler temperatures over the Northeast, followed by another warm surge by the end of the week.

Uncertainties Arise for Christmas Weekend 

If you’re on social media and follow some of the various weather pages out there, you’ve likely seen the numerous maps and forecasts that show a massive area of Arctic air dropping into the west, while a large area of warmth rises over the east. While the exact details of how this weekend will play out are still a couple days from being hashed out, what we know about this setup is that there will be a substantial amount of Pacific energy dumping into the west by Friday. All this energy injected into the flow will begin to carve out a large trough over the western/central US, while the downstream response will likely result in a ridge forming over or just off the southeast coast. This pattern will be supportive of increased heavy precipitation over the Southeastern to Northeast US as the gradient between the cooler airmass over the central US clashes with the relatively warmer airamss over the east on Friday and Saturday. Shortly after, the models begin to diverge on just how much the trough and accompanying cold is able to move east by Sunday/Monday. The other major question here will be where exactly does the ridge over the southeast set up? A ridge over the southeast will almost certainly guarantee an above-normal Christmas day, while a ridge off the eastern seaboard may allow cold to creep into the picture just in time for Christmas. These details will take a couple more days to flesh out, and we will certainly be monitoring them over the course of the week.

This afternoons European Ensembles showing a rather significant amount of spread in the overall 500mb pattern for Christmas day, showing nothing is set in stone yet.

This afternoons European Ensembles showing a rather significant amount of spread in the overall 500mb pattern for Christmas day, showing nothing is set in stone yet.

Stay tuned for further public updates! . Also join us at 33andrain forums for free discussion on everything weather-related.

Have a great night!

The importance of the EPO and upcoming cold risks

For some time now, we have discussed the likelihood that colder than normal air would be a common theme in the Northern and Eastern United States during the month of December. Like most things, it was not expected to be constant, but it was expected to be prevalent, and especially when compared to the past few December’s which featured nearly coast-to-coast anomalous warmth in the United States.

After a warm start, colder than normal air invaded the Great Lakes, Ohio Valley and Northeast during December’s second week. Winter weather threats have followed, with many areas recording multiple snowfalls. While this airmass hasn’t broken records, it has been just as anomalous as advertised, and has had an obvious impact on markets and businesses. After a brief period of moderation, forecast models are beginning to signal the return of arctic air into the USA – and this time it may be more anomalous than before.

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Wintry Mix for Interior Northeast Tuesday Before Arctic Blast Arrives, Late Week Storm Threat?

Good evening! Chilly and dry weather will continue for rest of the evening hours. But clouds will thicken and increase overnight, as the next storm system approaches. Mid-level warm advection ahead of warm front will start to cause Some light precipitation to break out well after midnight. Temperatures in the lower and mid-levels will be warmer, especially over New York City and coastal areas. So mainly rain is expected, although some snowflakes and ice pellets at the onset, can still occur. Otherwise, mainly some rain showers are expected through tomorrow morning, as temperatures rise into mid-upper 40s.

Over the Interior, especially higher elevations of Northwest New Jersey, the Hudson Valley and Northern CT more light snow, sleet and freezing rain is possible. This could leave coating to an 1″ or 2”, before perhaps change to rain during the midday hours. Temperatures will like rise only into the upper 30s to lower 40s in these areas during the afternoon. But should lead some snow and ice melting on on roadways and other paved surfaces. All precipitation will taper off during the early afternoon hours, as best dynamics begin to move northward into Northern New England.

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