So I have been keeping a close eye on the models the past few days. Seems we are in for quite a roller coaster ride, not to mention a tricky period to predict the weather. In terms of Winter weather in our area, i’m thinking we are on the wrong end of this ride. There is a lot of time for this to change, as it just did in the past 24-48 hours, so this writeup is more of what the models are seeing “right now” and my confidence is not too terribly high.
Here’s how the coaster ride shapes up.
Dec 10,11,12 – High pressure moves in and brings in the coldest air of the season. Everyone in Delaware will be in the mid to upper 30’s for highs. Sussex county will push the low 40’s.
Dec 13,14 – Precip event #1 – This event looked really good on the models a few days ago but is now looking to largely be a rain maker for our area. The problem is that the models had the entrenched cold air remaining relatively put which would have made it possible for some snow. Now the models are retreating the cold and even the upper level temps are showing too warm to even consider this anything more than a rain event. My last hope on this system will be when the remains of the massive low pressure that moved through Tue/Wed clears and allows the models to pick up the system in the south more clearly. Temps during this span warm up quite a bit with everyone in the high 40’s to possibly the low 50’s.
Dec 15,16 – Precip event #2 – This event two days ago was a storm of biblical making. Playing on the heels of event #1 and the deep cold, this was going to be a classic coastal low that slammed us with a lot of moisture and a changeover to snow with decent accumulations for all. Of course, since then the models have changed that and now it’s looking to be suppressed to the south. Some runs have the precip shield missing us to the south completely. Even with the miss to the south, the wind should change to blowing from the south which will warm us up even more. Temps during this time, dare I say, will be in the mid to upper 50’s with possible a 60 degree mark beeing ticked somewhere.
Dec 17,18 – High pressure takes a grip across most of the eastern half of the country and will allow the flood gates of cold air to open once again. Temps tentatively looking to be back in the 30’s for highs.
Wow, take the weekend off and come back in and what do I see. The GFS is calling for a cold snap starting Dec 10 and going on for several days. In addition, Dec 13 is starting to look interesting in regards for a chance of snow.
As far as the cold, get ready because the GFS projected temps are looking to be one of the coldest “cold snaps” we have seen in a long time. Currently the GFS has the high temps in the mid 30’s and lows in the 20’s and teens. Bundle up because baby it’s gonna be cold outside.
I want to call out Dec 13th because the GFS has temps below freezing all day with a projected precip total of 3/4″. If it all fell as snow then we are looking at 8-10″. This is definitely something we will need to keep watching to see how the models handle it as we get closer.
Well another 24 hours has gone by, which means we are 24 hours closer to the Dec 5/6 event. Looking at the GFS/NAM model runs over the past several hours is starting to show a very stead agreement that the low pressure system is going to be too far east to really impact our area with precip. Furthermore, the low pressure system that is coming through today and tomorrow is not going to pull down enough cold air deep enough to ensure that the precip that does fall is frozen.
So what does this mean? Well, the chance for accumulating snow with this event it becoming less and less likely to occur. With that said, the temperature just above the surface is still rather cold and will support snow. If the above freezing surface layer is not very thick it is still rather likey that we will have periods of snow on Saturday and Saturday night.
What to expect? Northern DE has the best chance to get temperatures low enough to support snow. Unfortunately, they are also the most likely to get the least amount of precip from this system. Central DE has an equal chance and may spend most the day with rain and snow going back and forth. Southern DE is going to fall victim to the ocean and not get the temps cold enough to support any snow until later in the evening when the system is moving farther off shore and may limit any chances.
Overall, this system should be the one that provides our first snow of the season, even though I have had unconfirmed reports that we had brief snow flurries on the early morning of black Friday. I do not expect much, if any accumulation.
Finally, its also worth noting that we still have two days to go before this even occurs. The accuracy of each model run will improve starting now and we will have a much better idea of what is going to happen.
Below is a 12 hour accumulated precip for the overnight of 12/5 – 12/6.
It’s winter time! Welcome meteorological winter. Yes, the “official” winter season does not start until later this month but for meteorologists, winter officially starts today!
If you noticed it was colder outside, your right, we are in the mist of pattern change. It’s not clear how powerful this new pattern will be just yet but its safe to say that the above average warmth we have been experiencing is going to be coming to an end.
Prime teleconections that are used to help determine mid range forecasts are beginning to do an about face. What this means is that the jet stream and major pressure patterns that influence the path of cold air will begin to change. If predictions for this winter hold true, this pattern change will put Delaware in an above average slot for cold and snow.
Dec 5,6 – First winter storm track of the season! The GFS has been projecting an off-shore low pressure system moving up the coast starting on Dec 5 and going in to Dec 6. It has been rather consistent with this event actually happening.
What it hasn’t been consistent with thus far is it’s track. Although lately the majority of the models are showing it far enough off shore to allow for some cold air to be pulled down over our area while the moisture is in place, some models have it hugging the coast where the temperatures would not allow for enough cold air to enter to achieve a change over to snow until well after the bulk of the moisture has passed.
The next 24-48 hours will tell a lot about what is going to happen. As of right now, I expect the media to start hyping a weekend snow storm.