By Alex Sosnowski, AccuWeather.com Senior Meteorologist
March 30,2015; 9:24PM,EDT
A significant change in the weather pattern is anticipated for much of the United States during the middle of April.
The pattern change could bring some rain and cooler conditions to California and the Southwest, snow for the high country of the Sierra Nevada and Rockies and colder weather for Alaska, according to AccuWeather long-range meteorologists.
According to AccuWeather Meteorologist Ben Noll, "There is increasing confidence in the arrival of a Pacific storm late next week, which can bring meaningful rains especially to central and northern California with some rain reaching as far south as Southern California."
The rainfall may extend beyond one storm. From mid-April into May, multiple storms loaded with moisture have the potential to track from the Southwest to the Deep South.
The pattern change could erase the persistent chill in the Northeast. The number of days with near- to above-average warmth could outnumber the chillier-than-average days in much of the mid-Atlantic, central Appalachians and the Ohio Valley.
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"If the pattern evolves as we suspect, it will also likely cause outbreaks of severe weather over the Central states as the storms move from the Rockies and onto the Great Plains," Noll said.
Warm, moist air will flow northward from the Gulf of Mexico on a regular basis and will not only fuel potential thunderstorms but also the risk of heavy rainfall over part of the lower Mississippi River Basin.
Rounds of rain and thunderstorms can also bring new flooding concerns to portions of Kentucky and Tennessee, spreading into Mississippi and Alabama.
"There will still be some tendency for chilly air to dip into the upper reaches of the Northeast, from the eastern Great Lakes to northern New England and neighboring Canada, but these areas should get a break as well," Noll stated.
The setup could lead to late-season wet snow events in the upper reaches of the Northeast. While temperatures will trend upward in the region, it could be just cold enough at times for snow during a part of the storms that come calling.
"As we get farther along into April, the chances of a rapid meltdown increase following any big snowstorm, and there seems to be that risk in northern New England and upstate New York," Noll said.
Several indicators are suggesting that the jet stream will shift position from its persistent or re-occurring southward plunge in the East.
"A northward bulge in the jet stream is likely to develop in the East with a southward dip in the west about a week or so into April," Noll said.
The jet stream is a high-speed river of air high above the ground that separates cold air to the north from warm air to the south. This change in the jet stream position will set the pattern change into motion.
According to AccuWeather.com Meteorologist Mark Paquette, "We expect an area of high pressure over the western part of the Atlantic to get stronger and create a south to southwest flow of warm air in the East."
"Lengthening daylight will erode the cold air over central Canada, which has been a stubborn source region for the chill in the Northeast," Paquette said.
The longevity of the overall pattern, once it begins, is a question.
There is the possibility that after a week or two into the new pattern it could flip back-and-forth between chill in the East versus the West.
"At least a harsh, long-lasting flip back to the cold pattern the Great Lakes and Northeast have been mired in since mid-January appears unlikely," Noll said.
Warm waters off the Pacific coast of North America have largely been responsible for the weather pattern across the U.S. and Canada this winter. The jet stream has been forced well to the north in western North America and southward farther east.
"Cold air that built up over Siberia and the Arctic region of Canada has had no where to go except into the Upper Midwest and Northeast," Noll said.
- Matthew Cooper · Top Commenter · Bellevue, NebraskaSo what happens in the Midwest? I should hope we stay warm as 2013 and 2014 were quite cold for us imo. This winter has been okay (minus November and February), but we also deserve a warm spring and a hot summer.
Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityThey said pattern change back in early Mar. It turned out not to be a pattern change but a shift or waxing/waning /deviation in the pattern.
Now once again we hear pattern change or flip. The test will not be over the next few weeks but over the next several months.
This could turn out to be a shift or a deviation/waxing and waning of the present pattern.
Seasonal influences are also present and El Nino strength along with the entire configuration of the Pacific /Atlantic sea surface temperatures will have to monitored to see if a true pattern change or flip really did start to take shape in April.
A pattern change is one that locks in and has very long lasting power, and has to be reflected by changes in the items that govern the pattern to begin with. Example sea surface temperature anomalies.
As I have said the models have predicted the last two winters quite poorly.
Time will tell.
Marlene Evatt Ansley · Top CommenterI really dread warmer weather. I love walking and hiking but when it starts getting warm and humid, it's uncomfortable. I miss those summers in the northeast when the highs were like in the 70s. It was wonderful.- Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityAs of today next winter looks as bad as this past one for much of the U.S.A. The only difference may be a cold AMO. Still to early.
As this decade proceeds the global temperature trend will be down due to prolonged minimum solar conditions which actually started taking place in late 2005.
This will lead to a more meridional atmospheric circulation. To get more details my website is climatebusters.org.
A site dedicated to destroying the AGW hoax.
Chuck Jones · Top Commenter · GCC
Ajdin-Aiden Kljajic · Follow · Top Commenter · Owner-Operator at Southeast Michigan WeatherOverall expect a roller coaster pattern over the next few weeks. Ridge/Trough etc... periods of very warm, and some periods of very chilly air across most of the eastern United States. I think west will cool down a bit, however the dry weather will continue.
Joshua Wade · Follow · Owensboro, KentuckyIf this Ridiculously Resilient Ridge returns once again for the winter of 2015-16, next Easter (March 27, 2016) is going to get ugly.
John John Griffin · Top Commenter · Traveling. Able to Do Me For Now at TravelingI TRULY hope that this is the last of the major snowy winters for the Eastern half of the United States because it seems that the west is missing out during the height of the season. They may get a few inches in October and November, but in the thick of winter it seems all the major snow has targeted the Eastern states for the last two winters for at least several years. We had some surprising big snows here in the South at the end of February and we just want to be done with it. Nothing like Boston but still we want to be done with it. We don't like Cabin Fever.
Félix A. Noël · Follow · Top CommenterI believe that Eastern Canada is reverting to what it was once: very, very cold (so that not suitable for modern civilization, megacities, etc.). Some experts say that the 20th century was one of the warmest in the last 1,000 years. During this time, we built majors cities, hydroelectric dams, waterways and a multi-billion-dollar agriculture industry in a place that used to be as cold as Siberia. Mass migration exit would take place in the next few years as resources are dwindling and people are exhausted by intolerable cold and snowfalls. This will have a major impact on economics and politics, including what is called "collapse".
Sherwood MacLeodup here in Ontario we haven't had any spring supposed to snow here tonight........we are tired of the cold as well.........
Scott Fourhman · Top Commenter · York, PennsylvaniaSnowed here in southern pa yesterday And it was windy barley above freezing I'm ready.
Teresa Burns · Works at Bigwoog Golf CourseWell all you Easterners. I am in Central Idaho and for the last month it has been in the 60's. And we are trying to have a ski season here! But sadly, our ski seasons have been getting more and more bleek. We want your Eastern snows!
Jonatas Torres · Top Commenter · Painter's Assistant at DeAngelis Iron Work, Inc.
John Hummer · Top Commenter · Wakefield HighMr. McGuire: I would give Accuweather a confidence rating on the April forecast in the EAST, about 20%...........because the pattern change does NOT include numerous 'back door' fronts they won't/can't see coming which will effectively blow the pattern change 'out the window'......and disappoint MILLIONS, anticipating the change they forecast!- Scott Fourhman · Top Commenter · York, Pennsylvania
Joseph Robert · Top Commenter · Silberman School of Social Work at Hunter CollegeMy best guess - the sun will rise in the east tomorrow. Days will get progressively warmer until about late August. Then they will get progressively cooler. About 50% chance of rain on any given day. Sun will definitely set in the west each day.
Christopher E. Corrigan · Top Commenter · Floor organizer/Trouble shooter at Self/Boston GlobeYes Joseph your predictions with be correct..Yes the weather will warm even thou the weather men says it will be cold then warm then cold again and it might rain or snow depends on with way the wind does blows..You are a better man than some of those wild drama queens and kings of the weather maps..Me think they protest too much and try to leave us in the dust..But Spring will have sprung and those birds will find their way back and the grass will grow green and long and the cold hard Winter will be so forgotten...
Grant McGuire · Top Commenter · Western Connecticut State UniversityIn other words, no real change is coming. If we see any warming, it will be like it was in March: a brief break before returning to the same cold. This is what we can expect all year.- Joshua Wade · Follow · Owensboro, KentuckyI cannot believe Spring 2015 is EXACTLY like Spring 2014 and Spring 2013, cold late start with trees staying dormant until early-mid April. The exact same thing will happen AGAIN in Spring 2016. March 2013, March 2014, March 2015, and March 2016 will be the definition of the four coldest Marches on record.
- Grant McGuire · Top Commenter · Western Connecticut State University
- Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityThe changes of late that I notice are two , El Nino Strengthening and Eastern Atlantic Cold , along with the seasonal change with everything else the same more or less.
How this will play on the present pattern will be interesting going forward, it could cause the present pattern to wax and wane , shift or flip depending on how extreme the change in the data is and or if other data points change.
For my money I am between wax and wane and a slight shift in the pattern but still think over the long run (one year time) the pattern we have now will dominate.
I know this is not a straight forward outlook but this is what I see for now.
Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTDCory Morrison I tend to agree with your assessment where you live. The thing about where I live is that our summers are mostly affected by the Bermuda High. If we get a strong Bermuda High along with the continued Positive PNA cold fronts your area will see frequent cold fronts passing through your area but they will tend to stall out over the Appalachian Mountains and then wash out if the Bermuda High is strong. That is why I am guessing June and July will be hot and humid and also stormy those months. (I think this will be similar to 1994 in our area). The winter of 1994 was brutally cold and was followed by the third hottest summer in Philly. The period from June 1994-July was the hottest June-July period in Philly since records were kept. And we had a F-3 tornado in the Philly burbs. I am not saying its a certainty but a possibility. It was almost like we went straight from winter to summer. Could happen again.- Neven Prvinic · Follow · Top Commenter · Cleveland State UniversityWayne, i do agree with you that 1994 is probably the closest analgo year on how 2015 may go, and i hope that comes true, as in my area Cleveland OH we do get effected by Bermuda high even though we are not too far south from where Cory Morrison is, i think his are benefits from Bermuda high as well if it is strong. By the way summer 1994 here was warmer than normal and very sunny, especially in June, July and September. August did come close to normal with few cool snaps. By the way we had one of the longer streches of 90+ in my area, nearly 2 weeks consequitive days in June 1994. Also going further 1994 had one if the warmest and sunniest falls as well which led into very mild and snow free winter 1994/1995
Severe Weather Mid AtlanticThis situation is very likely, but we may have to deal with some snow on Tuesday and this weekend, sadly.
Ian M. Sirota · Top CommenterI sure hope that this is accurate (please live up to your name, ACCUweather!), as I am really tired of the persistent cold/chill.
Goldminor Sanchez · Top Commenter · Saint Ignatius High SchoolI am also interested in seeing this forecast hold up. I had forecast an increased likelihood for late winter/spring rains for California and the west coast around 6 months ago. Part of the forecast I made has already happened, although I did not expect to see so much fall rain early on. I had the rest of the story correct with the warmer winter on the west coast and colder winter in the rest of the nation.
Meteorological Weather LabI'm sorry but I am "Snow " and "Cold" Lover here in the Northeast, this winter sucks because my home, "NYC" has not had a real "Blizzard" this winter which I have wanted for a very long time, reason I like snow and cold because heat and humidity gets disgusting after a while, skin is sticky.. lol people and places start to stink and that's what I've experienced, but when it is cold and snowy, the air seems cleaner and better to breath and from what I see, people clean up more often lol just my 2 cents.- Goldminor Sanchez · Top Commenter · Saint Ignatius High School
- Goldminor Sanchez · Top Commenter · Saint Ignatius High School
Philip Wexler · Top Commenter · University of Rhode IslandBeing in SE New England..I was very jealous of people in places like Medford, Ore. and Boise, Idaho having endless days of 65-70 degree weather the last few weeks when nudging 40 degrees was a major goal here.. send us some warm air now please!
Peter Kane · Top CommenterThe last two years showed a real struggle of spring coming, especially last Spring. What probably made the difference this March was the first week of March, where it was dead winter. This March overall, without the cold week, would have been near-average. There were some cold days here and there. Now, we are seeing spring, but it is not to its fullness.
Steve Palmer · Top Commenter
Aaron Ginther · Top Commenter · Lynchburg, VirginiaPeter, I agree. Despite the very cold start to the month (and the current cold snap) the rest of the month was actually seasonable with typical chilly days and mild days in the mix. We hit the 70's twice this month and many days in the 40's, 50's and 60's. It's been more of a problem for areas farther north. Look at Washington, DC and Richmond for example, both of these cities had plenty of mild early spring days. March 2013 and 2014 were much colder than this one, with 2013 being the coldest in my area. Except for early March and the current arctic outbreak, the other cold blasts haven't been far reaching or impressive here.
Last night we had a low of 18, which is impressive for late March but short lived. Tomorrow we're warming back to the low 60's then mid 60's on the final day of March.
- Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTDThe winter of 1994 was brutal in the east. However the summer especially June and July that followed were extremely hot. The west was hot also. The cooler temps were in between the mountains. And that was the year a rare F-3 tornado hit the Philly suburbs killing 3 people. So there is precedent to back up my hypothesis that if you are east of the mountains you will sweat this summer. the summer of 1994 was the third hottest summer in Philly and the month of July 1994 was the hottest month on record in Philly. The previous January and February were brutal.
John Durant · Follow · Top Commenter · 132 followersIf you believe this, I have a bridge I can sell you. There will be no pattern change. There will always be a ridge in the west, trough in the east. Its going to be a year without summer in the northeast.- Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTD
- Ian M. Sirota · Top Commenter
- Grant McGuire · Top Commenter · Western Connecticut State University
- John Hummer · Top Commenter · Wakefield HighThe last two sentences of the article speak VOLUMES about LR forecasting........confide
nce/knowledge beyond a week or two is limited! 
George Greene · Top Commenter · Works at TopShelf Oldies
- Joshua Wade · Follow · Owensboro, KentuckyI doubt this mid-April warm spell will last long, winter is coming back again in late-April and early-May with even more frigid temperatures and possibly some more winter storms into the beginning of May. I might not be surprised if this April actually feels more like a typical January for the entire eastern half of the U.S.
- Salvatore del Prete · Top Commenter · Southern Connecticut State University
Justin Witham · Top Commenter · Ball State UniversityHe doesn't have any reasoning. He keeps leaving comments like that on these AccuWeather articles. The other day he said "this April will be known as 'Arctic April'" and talked about there being below zero temperatures in the Midwest, which obviously is basically impossible in April. I think he's either trolling or is delusional.- Joshua Wade · Follow · Owensboro, KentuckyTrolling or delusional? Neither! I'm just a cold weather pessimist. In fact, since 2015 has become one of the coldest February-March ever, I can guarantee February-March 2016 will be even colder, even if the winter of 2015-2016 turns out to be as warm/mild as 2011-2012. If this April doesn't turn out to be the coldest April on record, then perhaps NEXT April would.
Christian GundermannAnd the other issue is that, whether it cools down or warms up, either way it always tends to bring more moisture. In the winter I can deal because snow can be removed (as long as it IS actually snow), but rain can't. Dreaming about desert climates!! I wish we could have some of that West Coast drought over here....- Christian GundermannEverybody always comment about cold or warm. All the long-term forecasts are concerned with whether it warms up or cools down. What I want to know is the precipitation trend for New England. I don't care so much one way or another whether it's warm or cold. You dress accordingly. The constant slush, rain, drizzle, sleet, rain patterns turn our little farm into inoperable muc and mire. But I suppose long term predictions about moisture are even more unreliable than about temperature trends.
- Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTDI think this was predicted in the spring outlook. I also think that this is a longer term pattern change. The I-95 corridor has seen normal summers the last 2 years. The area has not had 2 normal/below normal summers in a row since the late 70's. 2013 and 2014 were normal in m area (Southern Pa). So I think that while the east will still have its share of cool snaps even with the new pattern I think that in late May-early June summer conditions will return and a hot summer is in store for the I-95 corridor. Accu Weather did predict a warm May for the east coast and NWS seems to be indicating a hot summer east of the mountains in the NE/Mid Atlantic. The much below normal temperatures of Feb-March may be a distant memory by June.
- Salvatore del Prete · Top Commenter · Southern Connecticut State University
- Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTDSalvatore del Prete SE Pa has not gone through more than 2 consecutive normal/below normal summers since the late 70's. The summer that follows 2 consecutive normal/below summers has been hot every time since at least the late 70's. That is why I think the I-95 corridor may sweat this summer.
- Goldminor Sanchez · Top Commenter · Saint Ignatius High School
Carlitos Betancourt · Top Commenter · Monsters UniversityI want the SW to cool down we are looking at high 90s possibly 100 for tomlrrow Saturday! :(
Dorothy Ayer · Top Commenter · Owner/operator at Court Reporter
- Meteorological Weather LabGreat... The Snow haters are loving this...
- Grant McGuire · Top Commenter · Western Connecticut State University
Tom Atvrider · Network Engineer at Westfield State CollegeI am very skeptical. I bet big money on the opposite..Continueing way below normal temps. Not that I won't be happy if it does happen.- Aaron Ginther · Top Commenter · Lynchburg, VirginiaI think we're done with the cold in the lower Mid-Atlantic (MD, DE, VA) after this weekend. There may be some chilly shots but as far as prolonged cold, I'd say those days are over. March has already improved from January and February here. However, the lingering cold air may still hang around in New England after a surge of warmer air mid month.
- Cory Morrison · Follow · Top Commenter · Filing/Inventory Clerk at Independent Distributors Inc.I agree with Sal. Even if the cold pattern does ease in mid April, it may only be temporary unless if the GOA waters cool considerably.
- Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityEl Nino development will have to be monitored which could change the Pacific Sea Surface anomalies , that could alter the situation some but I still think it will not be strong enough to really change the dynamics. The warm water off the U.S.A /Canada West Cost has been the player as far as I am concerned in the persistence of this pattern.
- Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTDA strong Bermuda High will offset the warm Pacific Waters and could mean a hot summer for areas east of the mountains. We will have to see how strong the Bermuda High is and the position it is in. Cold fronts often come to a dead stop in the summer. So even if the Pacific waters remain warm I think that the below normal temps shift into the Upper Midwest and a battle zone sets up in the Mountains. Areas east of the Mountains could see lots of high heat this summer and also lots of strong/severe storms in the afternoon.
- Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityWayne you do make a good point because this year unlike last year shows stronger cooling in the Eastern Atlantic which should give rise to a trough, with a ridge to the West , how far west/strong is the question.
Then again that warm pool of water all along the West Coast of N. America is always going to try to promote ridging especially with the tongue of cold Pacific water to the West of it.
- Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityThe -PNA forecasted by the models into April , is behind this reasoning to some degree or another.
- Wayne Langhuber · Top Commenter · Tax Specialist at Professional Tax and Accounting Sevices LTDMeteorological Weather Lab NWS is showing a warmer than average May-July. That tells me that June/July is going to be hot as the Bermuda High takes control. I expect the PNA to still be positive but the cold fronts when they reach the Mountains will come to a stop and if you live in the I-95 corridor from DC to Boston expect lots of heat, humidity, and strong to severe thunderstorms. I see a period of high heat/humidity in July.
- Salvatore del Prete · Top Commenter · Southern Connecticut State University
- Salvatore del Prete · Top Commenter · Southern Connecticut State UniversityThis new pattern will not hold if it comes about as has been the case for the past two years. It is simply a waxing and waning of the current pattern with seasonal considerations superimposed upon this current pattern giving it a different configuration from time to time as has happened over the past two years.
This present pattern we have been having will be here more often then not unless the sea surface temperature anomalies change especially in the Pacific.
The models have been wrong on this pattern for two years as has been evidenced by the wrong winter forecast they have forecasted for the United States for the past two years.- Salvatore del Prete · Top Commenter · Southern Connecticut State University
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