An unsettled period of weather, beginning with the showers this morning, is going to last for much of the upcoming week. While it’s not going to snow or rain the entire week, precipitation is in the forecast most days through the upcoming 7 to 9 days.

The reason for the inclement weather will be a frontal system stuck to our south. This front divides cold winter air from warm spring air and, as it typical in April, this boundary will have a hard time moving north.

The meteogram below is from the GFS model. While there will be changes in the timing and amounts of rain and snow over the next week, the idea here is for lots of clouds, periods of precipitation and very cool temperatures. Notice how cool it is during the middle of the week. This is for Portland, areas outside the city will be even chillier.

Some of the precipitation will fall as snow. This could bring a coating to several inches cumulatively throughout the week. The best chance of any snow will be before Friday. I don’t expect a big storm and most snow won’t stick to the roads, but some slick travel could be a problem during the week.

Besides the models that forecast specific elements of the weather, I use a couple of long-range models to forecast general trends. One of these is called the CFS-V2 (Coupled Forecast System) and is run at different time intervals. I tend to review the model out to about 4 weeks. After a month, the model starts to weigh climatology more heavily and therefore isn’t as reliable. This model is related to the GFS and therefore can vary a lot with its European counterpart.

The model did a great job as predicting the cold February and March and continues to keep the northeast cool through next week. An example of one of the panels (courtesy of WeatherBell Analytics) is below. This particular forecast is for the 5 day period between April 8th and the 13th. The forecast is an average of several versions of this model. That’s why you see the words “ 4 Ensemble Forecast Runs Averaged..” This gives a more reliable forecast rather than just focusing on one version of the model.

You can clearly see the general position of the front dividing the cold and warm air during this period. Remember, this is a static image, the front will, in actuality, waver north and south a bit during this time.

I’ll be updating the forecast on Twitter @growingwisdom

Follow @growingwisdom

None of the precipitation looks very heavy next week. The best chance to receive wet snow will be later Sunday afternoon or evening through Monday morning, again on Tuesday and early Wednesday. Rain is likely Friday. Thursday appears to be the only day without any chance of rain or snow.

The trend is for milder air later in the week.

Copy the Story Link