The West: A storm moved onshore dumping rain and snow from northern California, up the coast and into Canada. To the south of the storm and into the Southwest, conditions generally degraded. Severe (D2) and Moderate (D1) Drought expanded in eastern California through the Las Vegas area and across most of southern Arizona, where Extreme Drought (D3) was also introduced.
Hawaii, Alaska and Puerto Rico: Drought conditions remained unchanged in Alaska and Puerto Rico this week. In Hawaii, Torrential rains slammed the state, according to the National Weather Service. Forty-plus inches of rain fell on parts of Kauai while parts of Oahu received nearly the same amount. Overall, the rain led to improvements in Exceptional (D4), Extreme (D3), Severe (D2), and Moderate (D1) Drought and Abnormal Dryness (D0) on Molokai, Maui, and Oahu.
Looking Ahead: During the March 15-19, 2012 time period, there is an enhanced probability of precipitation in the Pacific Northwest throughout the period and in the central part of the country late in the period. Temperatures are expected to be above normal east of the Rockies.
For the ensuing 5 days (March 20-24, 2012), the odds favor normal to warmer than normal conditions over the entire US, east of the Rockies. West of that, normal to below-normal temperatures are expected. Precipitation is expected to be below-normal along the East Coast and in the Southwest. Above-normal precipitation is expected in the Northwest and from the Southern Plains through the Midwest. In Alaska, both temperatures and precipitation are expected to be normal to below-normal.
Author: Michael Brewer, National Climatic Data Center, NOAA
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)