January 12th, 2025

 

The week ahead and longer range 

 

Week ahead:

This weekend has had seasonal temperatures with greatly reduced winds. Tomorrow will be basically dry, with the chance for a few snow showers during the afternoon.

Monday a clipper-like system will drag an arctic front across the region, on the leading edge of this front we will likely see flurries and locally heavier snow squalls, these squalls will lead to a sudden drop in visibility. With the front there is a good chance for a flash freeze. The front will make it into the mid-Atlantic and Coast of New England Monday overnight into Tuesday. Winds will be gusty. A general dusting to an inch or two of snow may fall in these bands. This arctic air dropping in behind the front will kick off heavy lake effect snow for Monday night through Wednesday. Winds will at first be out of the West, allowing accumulating lake snow for those downwind East of the Lakes for Monday night into Tuesday. Then for Tuesday night and Wednesday, the winds will shift into the northwest, pushing the lake effect snow bands southeast to south of Lake Erie and Lake Ontario.

 At times lake-effect snowfall rate will reach up wards of 3 inches per hour, those under the most persistent bands will likely end up with several feet of snow with blizzard-like conditions possible. The lake snows could extend into Thursday. Away from the Big Lakes the rest of the region should be cold but generally dry. Winds will be calming down Thursday and Friday, with temperatures warming up, but the warmer temperatures won't last for very long. 

January analysis:

 

The snowpack across the northern tier of the U.S. and across Canada, will aid the likelihood of the cold air sticking around into February.

La Nina has finally emerged in the equatorial Pacific. It took a little longer than I thought, but it’s now officially here. But it is very weak, a bit weaker than I thought it would be. La Nina’s this weak, tend to have a weaker influence over temperature and precipitation patterns. But that doesn’t mean it won’t have any impact; for the last few months the SST in the Nino 3.4 region have been negatively negative, bordering on La Nina. For that reason, the pattern has been similar to what one would expect for a La Nina, with overall temperature and precipitation patterns acting La Nina like. Also, the Atlantic hurricane season activity performed like it had been La Nina, with lower-than-average wind shear. This winter has seen blast of arctic cold with numerous snowstorms. With the La Nina so weak, it most likely won’t last all that long. So, the La Nina could end April into May with El Nino Southern Osculation (ENSO) conditions becoming neutral (not either La Nina or El Nino). With the Weak La Nina other atmospheric teleconnections, like the Atlantic Osculation (AO), North Atlantic Osculation (NAO) and Madden Julian Osculation (MJO) will exert a lot of influence.

 With the pattern developing, the western ridge will shift west near the Aleutians, allowing for general troughing to move into the eastern two thirds of the CONUS. We’re likely going to see the Polar Vortex become stretched again, allowing arctic air to drive south. By the end of this week, we will be watching a disturbance near or over the Gulf of Mexico, with an area of Gulf Moisture. At the same time, we look to see energy dropping out of western Canada and the Northwest CONUS. There is a chance these will interact and maybe phase, which will allow the developing storm to push east as it rides the boundary. There are hints that this will try to come up the East Coast. If so, parts of our region in the Northeast could see snow out of it.

Behind the storm, we’re going to see a large surge of arctic air drop into the CONUS out of Canada. This is likely to be the coldest air of the season so far over the Plains into the Midwest.  As this air migrates east, it will modify a bit; but the airmass will likely still be at least as cold as we’ve seen earlier this month. Over the last several weeks, we’ve had a series of arctic fronts drop across the CONUS into the Gulf and Caribbean. How far south the arctic front for around Martin Luther King Day will get is unclear, but it will likely make it at least into the Gulf Coast and Florida.  During this time the AO and NAO will be weakly negative to natural, so this will promote weak to at times moderate blocking near Greenland. The MJO is in phase 8 this looks to propagate through phase one then phase 2. As I’ve said before, during January, when the MJO is in phases 7 through 1 it promotes troughing in the East. This very well could counterbalance the AO and NAO, increasing the chances for East Coast snow over the rest of January.

This will mean some storms could be suppressed south, while others try to come up the coast, depending on how strong the blocking is at that time. I do expect to see a few lake cutters depending on the location of the trough axis. The active pattern should continue to produce clipper like storms, that bring shots of reenforcing cold and chances for light to moderate snow.

What about February:

After our current warm up, the rest of January is looking to stay cold. We need the cold in place before the storms, if we want snow storms.  We won’t be super cold all the time, but we should see temperatures stay generally below average. Looking back at the MJO, we can see it goes into phase 3 and then phase 4. If that does occur, we could see general coldness heading into the first part of February before we warm back up.