Wednesday, April 11, 2012

More On Dry Weather

It seems that there's been quite a departure around here than we've seen over the last couple years regarding precipitation. What has frequently been too much rain is now decidedly too little. There's been some nice weather the last few months, and the price to pay for it is starting to become apparent.

There are two really good ways of monitoring drought or dry spells. 

Last week's US Drought Monitor
Credit: UNL
The most basic is the one everyone is probably most familiar with: The Drought Monitor. 

The Drought Monitor basically gives you the head's up regarding what sort of drought you're in. Is it a long-term severe drought (see Georgia, Florida, and West Texas)? Is it a standard drought (see Minnesota and much of the West)? Or is it abnormally dry, meaning any sort of precip or lack thereof will tip the scales one way or another? That's what the Delaware Valley sits in as of the April 3rd Drought Monitor (an updated version of this will be released tomorrow morning). While the Drought Monitor is good, it doesn't really tell you how serious the shorter-term or developing drought may be. For instance, much of Texas is in a long range, long-term drought, but abundant rains the last few months have wittled away most of East Texas. However, while the ground is saturated there and a ton of precip has fallen, they still fall into the "long term drought" category.

Short-Term Drought Indicator
Credit: CPC/NOAA
So for a better perspective on a snapshot of now, I like the CPC's "Objective Short Term Drought Indicator." While the region has seen abundant rainfall in the last year to prevent it from going into real drought, you can clearly see from the map at the left, that much of the Northeast and Mid-Atlantic are in pretty significant short-term drought conditions. This explains the significant increase in wildfires of late. This may also have an interesting impact on temperatures Sunday and Monday...with super dry soils, this often enhances heat, so many forecasts may underestimate how warm it can get those days. Of course, there are a number of other issues (such as clouds and timing of precip) that could render that point moot, but it will be worth watching.

All in all, you get the picture. While the Drought Monitor is good for long-term trends, you can clearly see that in the short term, the area is in a fairly significant drought type pattern and will need a good bit of rain to start recovering...something to keep an eye on as we get deeper into spring and, ultimately, summer.