Winter ’23-’24 Outlook Discussion

Not Forecasts – Just Thoughts, Conjecture and Speculation about possible upcoming storms and trends in the extended range.

Coverage of each potential storm will move to the main forecast blog page when the possibility of a storm moves from speculation to probable/likely.

#Philadelphia #weather #PAwx

No Snow for through at least March 5th

Posted Friday 02/23/24 @ 7:48 PM — A rapidly changing progressive jet stream flow with an increasingly warm bias and recurrent ridging in the Eastern US looks to to be the case through the first week in March. A couple of chill downs with cold fronts, but quick rebounds to above average seasonal temperatures.

We also seem to have broken away from the extreme rainfall storms for now with blocking high pressure in the western Atlantic. This is feeling like a pattern change for us that may extend into Spring.

02-23-24 18z NAEFS forecast for March 3rd captures the general pattern. Recurrent eastern ridge with warm temperatures. High pressure anchored off the coast blocking low pressure systems that will move up through the Great Lakes.

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Posted Wed November 29,2023

Winter Outlook Discussion—I often get asked about the coming winter weather outlook, especially about the potential for large snow storms.

Disclaimer: Climate forecasting and weather forecasting, while related, are very different animals. While I know I’m pretty good with weather forecasting, my climate forecasting remains in the realm of an educated soothsayer.

One thing is clear. The current pattern is very different than last year. I described the difference in jet stream position in the immediately preceding previous post of Nov 12th.

I am seeing some things lately that suggest a stormy winter, specifically the tendency to have frequent coastal secondary low pressure development with a sharply dipping jet stream in a somewhat favorable position. The million dollar question will be the amount of cold air that can be available for a snowstorm here in Philadelphia. Even in colder years, before the current climate changes, Philadelphia was often on the border of the rain-snow line.

With climate change, that rain snow line will most likely be even slightly further north and west of our area.

I do see large swings in temperatures likely as well for the winter. Our January thaw could have a week of 60s and even 70s at some point.

But with all that coastal storm development lately, a few good snowstorms this season look to be a better possibility than last year.

Yet I wouldn’t be surprised if the majority of our storms become mixed precipitation type events with rain changing to snow or snow to sleet/rain in Philadelphia and the immediate suburbs.

I know I’m hedging here. It just takes one big storm to kill a winter climate outlook.

Posted November 12, 2023

Winter Outlook Discussion —Which brings me to the winter forecast. Frankly, I think we’re going to see large swings in temperatures here with primarily mixed precipitation events here. Not necessarily large accumulation snow storms.

The jet pattern these past several months has been somewhat different than last year. With almost no accumulating snow last year, it’s unlikely to be similar, but it doesn’t mean we’re “due” for big snow storms.

Last winter, a persistent dip in the jet had the main axis of the trough directly over us, causing storm formation to occur in the Atlantic. This year, I ‘m seeing more favorable positioning of the axis of the jet dips (more to our west), but favoring warm air preceding any storm. The major storm developments over recent months have all been to our north and east, missing us. Will that continue?

Patterns change; what we have now could be different in January. But the trend towards warmer temperatures may be an increasingly large factor when it comes to getting large snow storms here.

2 thoughts on “Winter ’23-’24 Outlook Discussion”

    1. An interesting thought and comparison. I don’t think we know the answer to that question just yet. And too soon to write off a storm here this season. Patterns can change dramatically in even 4-6 weeks. But I’m amazed at how much warm air is advecting northward and how little cold air is advecting southward.

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