A pretty nice weekend is on tap for us in the Ohio Valley area. Still a bit cold, but bright sunshine will make the low 40s tolerable once again! It will be on Monday that our next chance for significant weather arrives. And it arrives just as a blocking pattern is kicking into high gear.
Let’s look at our old friends the indices. It’s been awhile since I’ve posted these, so I’ll explain for those of you that aren’t familiar with them.
First, the AO (Arctic Oscillation). Dashed line is neutral. Red lines are the predicted trends, multiple lines because this represents multiple models producing a forecast. Notice that it’s negative right now and it’s going to stay that way – that’s what snow lovers want. It means cold air is available for the Ohio Valley.
Then we have the NAO (North Atlantic Oscillation). Notice that it’s also negative and will stay that way. A negative NAO indicates a blocking pattern in the Atlantic Ocean. This forces storms to stay for an extended period of time in our area. As a fellow meteorologist puts it, a negative NAO means the Atlantic is closed for business.
Finally we have the PNA (Pacific North American Teleconnection). It’s positive and will stay that way. Positive PNA means that cold air is on the move into our area and it will stay there when it gets here…until something changes the PNA to more neutral or negative.
These indices will greatly affect our outcome next week. And it looks like another monster of a storm coming in! Thankfully, I don’t see any icy precipitation for us like the last one. But the Great Plains are going to get hammered with yet another major snowstorm. Some places that already got a foot of snow are looking at yet another foot of snow!
GFS for 1am on Tuesday shows heavy rain bands moving into our area. It’s already been raining here at this point for quite a bit. Notice the heavy snow on the backside of the low. Normally in a setup like this, we’d see this pass by pretty quickly and it’d be out of the area by late Tuesday. Not so this time because of the blocking pattern.
GFS for 1pm on Wednesday. Storm is still around in the area! Notice that the low has weakened considerably. It was 987mb and now down to 993mb. Still a fairly strong system, but weakening. What’s happening is the upper level low is starting to dominate instead.
Here’s a view of the upper levels of the atmosphere at the time – 500mb level or about 18,000 feet up. The upper low is really the dominant feature now and notice the strong winds shown over us. That’s some pretty strong lift to force some snow showers over us!
What we’ll see next week is a snowstorm out of the ordinary for us. Normally the surface low moves on and we see just a small amount of snow on the back side of the system as it moves past. This system just sits in the region and spins over the area for a few days. That means the atmosphere will cool from the top down. Temps at the surface will take awhile to really cool enough for snow to stick, at least during the daytime anyway. But if we see some snow showers during the nighttime, we could easily see some snow accumulation from this.
And the accumulations won’t come all in one fell swoop like normal. It will come over a period of a few days! It won’t be out of question with this type of setup to see an inch or so each day from this. And given the dynamics in the upper levels, some convective snow showers during the daytime might be possible, but accumulations there might be limited due to the temps above freezing. Remember last week when we saw four inches of snow during a couple hours in some areas? It didn’t last long, but it caused temporary problems. That was convective snow and that’s what we might see from this system.
When can we expect these snow showers? Monday looks fine for just rain, but later in the day on Tuesday I think we might see the transition to off and on snow showers. And those snow shower chances will last on Wednesday, Thursday and Friday! And actually, the pattern doesn’t look to break anytime soon. So next week could just be a nasty week for us. The wind will also be a story worth noting. It looks breezy almost every day next week, winds from 10-15mph common.
Just when will this yucky pattern break? Look at the GFS for next Sunday the 3rd. Notice this system is still sticking around and causing snow showers for the area! Talk about annoying! GFS indicates March 5th before this system finally moves off shore.
EURO model moves it off just a bit faster, as does the GEM. If this pattern holds out, we’re in for a nasty week next week!
Here’s the BUFKIT view for the GFS next week. Just to give you a visual idea of precipitation type. Green is rain, blue is snow. Days are at the bottom. You read this from right to left. Snow chances kick in overnight on Tuesday and last all through the end of this model view and then beyond really. As I’ve said several times now, a nasty week in store!
As always, I’ll be monitoring the situation throughout the week and providing you with up to date data. I update Facebook andTwitter often. Be sure to like those pages to keep up to date! And check out our new website for even more great information, including a full 7 day forecast updated every morning!
Enjoy the weekend while it lasts! This beautiful sunshine is gone by Monday.