A Widespread Heavy Rain Event Is Expected Tonight Through Tuesday Morning With Localized Flooding Likely: The big concern in terms of weather is going to be the likelihood of a widespread heavy rain event that occurs during tonight and all of Tuesday morning across all of Western and Central Mass. I do have some concerns that we could see areas of localized flooding, including street, highway and poor drainage flooding, especially between about midnight tonight and mid-morning on Tuesday.
The environmental conditions are expected to be extremely favorable tonight for widespread heavy rain and localized areas of flooding. We have a very moist easterly wind flow in the low-levels of the atmosphere, which is importing a lot of Atlantic moisture into our area. At the same time this is occurring, there is forcing occurring from a low pressure system and its associated warm front that’ll move through the area during tonight. This combination can sometimes lead to localized areas of very high rainfall totals & this is something that’ll need to be watched extremely closely.
The various weather forecast guidance are of little help in determining exactly where the highest rain totals will occur. Some guidance show the highest rain totals in excess of 4 to 6 inches to occur in the Springfield Metro & also across southeastern parts of Worcester County. Other guidance are pointing towards the highest rain totals to occur across northern parts of Worcester County. This huge difference between reliable guidance is making this a very difficult forecast & I think that we are looking at a “nowcast” situation tonight and Tuesday morning where I’ll be looking at which areas are seeing the heaviest rains in real-time & warning as such.
Here Are My Thoughts Based On The Latest Data: Steady rain is expected to continue throughout the rest of this afternoon near and south of the Mass Pike. North of the Mass Pike, a period or two of rain is possible & actually it will likely be dry for a majority of the afternoon.
For Tonight – Steady rain is expected to expand northward and overspread all of Western and Central Mass by early this evening. During the after midnight hours of tonight, the rain is expected to continue across the entire area & periods of heavy to very heavy rain can be expected. What we’re going to have to watch out for is the potential for repeating bands of heavy rain occurring over the same areas. Should this occur, then the flood threat would increase dramatically.
Turning to Tuesday Morning – Rain, which will be heavy to very heavy at times, will certainly impact the morning commute across the entire area. This rain is expected to last through mid-morning before it begins to lighten up and end towards midday. Again, what is going to have to be watched is the possibility of repeating bands of heavy rain occurring over the same areas. These very localized very high rain totals are, unfortunately, something that cannot be forecast until “game time”. That being said, it is something that I will be monitoring extremely closely.
Total Rainfall Amounts: Based on the totality of the latest data, I think that we are looking at widespread rain totals of 2 to 3 inches across all of Western and Central Mass. While these rain totals shouldn’t be enough to produce widespread flooding, they may be enough to produce areas of flooding, especially in low-lying areas & areas of poor drainage.
As I already mentioned, I do have great concerns that we could see localized rain totals of upwards of 4 to 6 inches across some part of our area. Where exactly this occurs remains to be determined. That being said, there are a couple of areas of concern in terms of localized very high rain totals.
One area is from the eastern Hilltowns of Western Mass eastward into the western and northern Worcester Hills where the very moist easterly wind flow will be lifted over the hills leading to the potential for very high rain totals.
The second area of concern is across an area from the lower Pioneer Valley, including the Springfield Metro eastward to across far southern parts of Worcester County (areas that are located south of the Mass Pike). These areas will be closest to the forcing and moisture combination from the warm front and low pressure system & thus localized areas of very high rain totals are a possibility.
It goes without saying that I will be monitoring the weather data extremely closely this afternoon through Tuesday morning in trying to determine which areas, if any, will be hit the hardest. Additionally, I will also be closely watching the radar data in seeing where the bands of heavy to very heavy rain sets up & then update you accordingly.
Many more weather updates will be posted as needed between later this afternoon and Tuesday morning. So, keep checking back.
