Drought in Delaware

Highlights:

• Precipitation has returned to normal to above normal levels over the past 30 days for most of the state.  
• Soil moisture and streamflows have improved some, but still remain seasonally low.
• Groundwater levels are improving, but we still have quite a ways to go to get back to normal levels
• Very little precipitation is likely in the near-term, but medium term (2-4 weeks), most indications point to above normal precipitation as we transition from winter into spring. 

Statewide Drought Discussion

Stream conditions in New Castle County showed slight improvement resulting in a little extra breathing room as we head into the last week of February.  The chlorides in the Christina River near Newport decreased below 100 ppm, which is the lowest chloride concentration since the week of January 13th. The water level in well Db24-18 has remained steady at 15.5 ft below land surface (drought warning). The water level in this well typically ranges between 10.0 to 14.2 ft below land surface during the month of February. Db24-18 will enter drought emergency once the water level in the well drops to 16.0 ft below land surface. The normal range for March is between 9.2 and 13.0 ft below land surface, so we need enough rain during the remaining days in February and the month of March to bring the groundwater in this well up 2.5 ft to get us to the low end of normal.

Precipitation in February has been at or above normal for just about every part of the state.  The map below shows precipitation totals from the DEOS Network for the last 30 days. 

Southeastern Sussex County has seen the most precipitation, with nearly two inches above normal precipitation for that timeframe.  About the only area that hasn’t seen above normal precipitation is southern New Castle County, which is about a half an inch below normal. With precipitation being adequate or better over the last 30 days, soil moisture has correspondingly improved, with most of the state having between 30 and 60 percent of soil relative field capacity in the top one meter of soil.  Ideally, we’d be close to 100% by now, but this is significantly better than a couple of weeks ago when most of the station was between 25 and 40%.  Groundwater levels in Kent and Sussex counties are improving.  Well Mc51-01a, which is located in the southwest corner of Kent County, has seen a nearly 1 foot improvement in depth to water since the end of January (see graph below).  With more precipitation, we should continue to see some recovery in the groundwater levels throughout the state.  

Weather and Climate Outlook:

The forecast for the next week is fairly dry, with the only chance of any meaningful precipitation occurring tomorrow into Friday.  Most models are showing another storm system coming through our region late next week and it’s too early to know if that system will be a significant precipitation maker for Delaware.  Here’s the Weather Prediction Center’s 7-day cumulative precipitation forecast:

It looks like more wet weather for an already flood-weary Ohio Valley region over the next 7 days, while the mid-Atlantic largely stays dry.  Looking beyond the next 7 days, most of the sub-seasonal indicators have us remaining in a fairly active weather pattern over the next month or so as we transition from winter to spring.  If that is the case, we may have some opportunities to see significant precipitation and replenish the water we need in our natural systems for the upcoming growing season.