Rain Timeline Update Mon Afternoon And Tue

Looking at the weather map is is quite simple and complicated at the same time. It is stormy to the south and dry to the north. Guess where is right in between? Our good ol’ Mid Atlantic. Do you just want to know if and when it is going to rain? I get it. I wish is was that easy, but our region will once again be on the edge today as rain moves in from the south.  Then throw in Tropical Storm Kate to the mix and we have one more force pushing on the storm.  In short, rain will over spread tonight and Tuesday will be wet. The simulated radar is below if you want to skip to it, but I feel compelled to explain a little more.

Last night I wrote about a pattern of storms trending south and east while eroding away the northern edge of rain. This can delay the arrival of rain, on clip the storm all together for some.  Yes, there is a storm. Actually two of them! While watching TV reports or pics on your newsfeed it is easy to be lulled into seeing the worst flooding and thinking its all that.  But the rain spreads out farther where it can influence your plans without making headlines. Thus is my job here. What it means for us.

Split Rain

The mid level winds shown here for Tuesday Morning will be the flow of moisture at cloud level.  Notice the storm to our south. There will be increased winds over the ocean in part as the atmospheric traffic jam with TS Kate far away. The pressure can pick up more moisture, but that will be directed inland to another upper level feature. Add in the lift from the mountains and there will be two pockets of moderate to heavy rain, but much of central Maryland and the I-95 corridor will be on the lighter side. Still a half inch possible, but the bulk will fall in the hills and mountains west, and the coastal plane along the primary storm track.

See the rain total forecast below the simulated radar and timeline

Radar Simulation

Battle between dry air and some moisture filling in from Chesapeake and Atlantic.

If you remember the clear cold night or even sunny start this morning, then consider this is a winter type pattern.  The air mass moving out is dry and slow. The rain moving in can trick the radar and models. So the northern edge of this could be virga. This is when it shows up on radar, falling from the clouds, but dries up before reaching the ground.  There will be an invisible block from the dry air roughly around I-70 give or take 20 miles late afternoon and evening.  That seems to be where the dray air may hold while the wind flow from the Bay and ocean help the rain fall.  The wall will break down with the main push of rain overnight.