It's Tuesday. Once again we have rain on our doorstep. Here's what to expect with this upcoming system.
A cold front separating cooler, drier air in the Upper Midwest is sliding east and crashing into warmer and more saturated air hovering over New England. The interaction of these two air masses will create some rain which could be heavy at times. Here's a look at the Precipitable Water as of 8 a.m. Tuesday, June 12.
You're looking at higher amounts of moisture in the atmosphere across the Northeast. The darker greens show a plume of moisture stretching up from the southern United States. If you recall, the Southeast got hit with lots of rain earlier this week and that moisture is now moving northeast, getting pulled into our area with the incoming weather system.
Precipitable Water can be explained this way: If you squeezed out all the moisture in the atmosphere, similar to squeezing out a sponge, it would be that amount. For instance as of 8 a.m. Tuesday our area had a (Pwat) of 1.25 inches. If we squeezed it all out we could get 1.25 inches of rain.
So in other words that axis of 1.8"-2.0" is pretty decent. We don't see it too often in our area. Some heavy downpours will be possible because of that moist air coming on.
I'm thinking a widespread 0.50"-1.00" of rain out of this system, from rain between 2 p.m. Tuesday to 2 p.m. Wednesday. As of right now it's not enough to cause widespread flooding.
This is the flash flood guidance for our area under a three-hour rainfall, courtesy NOAA. The ground can handle about 2-2.5 inches in a 3-hour period as shown here. Thus there is room to give with the rain coming in. Still, if 1.5" were to fall in a 3-hour period I think minor and localized flooding would occur in areas that have poor drainage or 'usual flooded spots.'
Turning to another interesting note: This will be the seventh Tuesday in a row that Burlington has had measurable rain! Here's the last seven weeks of data for the Burlington International Airport in S. Burlington, VT:
Tuesday, May 1st: 0.46"
Tuesday, May 8th: 1.23"
Tuesday, May 15th: 0.49"
Tuesday, May 22nd: 0.15"
Tuesday, May 29th: 0.49"
Tuesday, June 5th: Trace
Tuesday, June 12th: ???"
Trace is the least amount of measurable precipitation, but it still counts! The green highlighted date of Tuesday, May 8th was the single wettest day of May 2012 in Burlington. Also May 29th was the day of that severe weather breakout across the region. Can you see a revolving weather pattern? At least this has translated to beautiful weekends, sunny and dry (with the exception of one June 2/3). So I don't mind this one too much :)
-Meteorologist Steve Glazier