Northeast: The Northeast saw some spotty, light precipitation last week, but not enough to warrant any improvement to the existing pockets of D0 as we head into March.
South Atlantic and Central Gulf Coast Regions: After a couple of active weeks brought several pulses of moisture and improvement to the region in early to mid-February, the past week was much quieter, resulting in few changes to this week’s map. Some continued improvement was noted in southern Alabama and parts of the western Florida Panhandle, which goes from D2 to D1. Persistent rains in west central Florida led to a slight trimming of the D2 and D1 there. Farther north, western North Carolina continues to dry out a bit, leading to a slight expansion of D0 in that region. Status quo is the word across the rest of the Southeast this week.
The Southern Great Plains and Louisiana: The tap turned off across all of the southern Plains and Louisiana as well last week, leading to few changes after several weeks of improvement. The only change of note is a slight expansion of D4 in the Big Bend region of west Texas. Most of the region warmed up as well, posting above-normal readings accompanied by much windier weather of late.
The Northern Plains: The past few storm systems have dumped some wet snow across the region, leading to some minor improvement from D1 to D0 in southeastern North Dakota this week. The rest of the region remains unchanged.
West: The most active weather was mostly confined to the Pacific Northwest this week with cooler temperatures prevailing except for the Southwest, which saw above-normal temperatures. Some of the better precipitation fell across parts of the continental divide in north central Colorado and up into southern Wyoming, leading to minor reduction of D0 and D1 there. Favorable Water Year numbers also lead to readjustments and trimming of D2 on the central border between New Mexico and Colorado.
Bigger changes occurred farther west this week with more introduction and expansion of D2 across the Wasatch Range in Utah, more of northern Nevada and farther south across the Sierra-Nevadas in California. Water Year snow water equivalent values are historically low with not much in the way of time to make up the extreme deficits. Most of the region is still living off the benefits of good snows and water from last winter, which may help to mitigate impacts to some degree, but there are already concerns about water allocation limits during the upcoming growing season.
Hawaii: There are many notable changes across the state this week, starting in the west with Kauai, where favorable rains led to the removal of D0. Oahu also shared in the improvements with a reduction of D1 to D0 there. The rains didn’t come to Molokai this week; reservoir levels continue to drop and water restrictions remain on agricultural activity, leading to an introduction of D4 across the western half of the island. Maui remains dry as well, especially on the leeward side where D3 has encroached upon the Upcountry and Kaupo areas, leading to rangeland/feed issues for livestock there. The Big Island saw a bit of both worlds (wet and dry) last week as the windward side received ample precipitation, which led to a reduction of the D0. On the Kona side, D1 had been degraded to D2 and D3 has expanded northward from the South Kohala region into the lower leeward reaches of the Kohala Mountains.
Looking Ahead: During the next 5 days (March 1 - 5, 2012), the forecast calls for a good chance of heavy rains across parts of the Southeast, particularly northern Alabama, northern Georgia and the Carolinas. Florida and other parts across the coastal Gulf Coast regions can also expect more modest, normal-like totals for this time of year. The Pacific Northwest remains in its active pattern, which may also be shared across the Sierra-Nevadas and the Wasatch Range in Utah as well. Temperatures are expected to be below normal for most of the West over this time period while most everyone else east of the Rockies can expect above-normal readings except for the northern Great Lakes region and into Minnesota, where cooler temperatures should prevail.
The Climate Prediction Center (CPC) 6-10 day (March 6 - 10, 2012) outlook is favoring another wet period across the Pacific Northwest. The Southwest and southern Plains don’t look as good during this period, with below-normal precipitation being most likely. Temperatures across most of the Intermountain West and coastal Pacific states are expected to be below normal. The eastern half of the country from Texas to the Northeast and Southeast is looking at good chances for above-normal temperatures.
Author: Mark Svoboda, National Drought Mitigation Center
D0 ... Abnormally Dry ... used for areas showing dryness but not yet in drought, or for areas recovering from drought.
Drought Intensity Categories
D1 ... Moderate Drought
D2 ... Severe Drought
D3 ... Extreme Drought
D4 ... Exceptional Drought
Drought or Dryness Types
S ... Short-Term, typically <6 months (e.g. agricultural, grasslands)
L ... Long-Term, typically >6 months (e.g. hydrology, ecology)