National Drought Monitor for November 11, 2014
Summary
Three low-pressure systems impacted the contiguous 48 states this week. The first system wrapped up over the Great Lakes before moving toward the Canadian Maritime Provinces and pushing a cold front off the east coast. Significant rains (0.5 to 3.9 inches) fell along the southern end of the front over Texas. During the weekend, an Alberta clipper type low-pressure system moved across the Great Lakes but triggered little precipitation. Earlier this week, significant snows fell across the northern tier of the contiguous 48 states as cooler air funneled in across the Great Plains.
Looking Ahead
During November 13-18, wet weather is forecast for the eastern third of the Nation and from Oregon and Northern California to the Central Rockies. Rainfall totals are likely to exceed 4.0 inches across Oregon, with lesser amounts elsewhere. Gulf moisture is likely to support rainfall of up to 2.4 inches from southeast Texas to Alabama. Lake enhanced precipitation is also likely downwind of the Great Lakes as northwesterly flow is expected to persist for a few days during the early portion of next week. Cold and dry conditions are likely across the Great Plains.
For the ensuing 5-day period, November 18-22, odds favor below normal temperatures east of the Continental Divide, with above normal temperatures west of the Continental Divide. Above median precipitation is favored from California to western Montana, and across the southeast from Louisiana to the Carolinas. Below median precipitation is likely from the southern High Plains to the Upper Midwest and across the Mid-Atlantic and New England coast. Most of Alaska is likely to receive below median precipitation, except for the south central coast and the Alaskan Peninsula.
Alaska, Hawaii, and Puerto Rico
A full 1-category improvement was necessary in response to the moderate to heavy rains (1.5 – 9 inches) that covered Puerto Rico. Abnormal dryness was retained where 60-day precipitation totals are less than 50% of normal.
Mid-Atlantic and Southeast
Abnormally dry conditions (D0) continued across the Mid-Atlantic. United State Geological Survey (USGS) streamflows and 60 day Percent of Normal Precipitation (PNP) were both indicative of the recent dry conditions across Virginia. Streamflows in North Carolina have yet to show as steep of a decline, but precipitation deficits are mounting out through 90 days, but were most prevalent at 60 days, according to the precipitation estimates from the Advanced Hydrologic Prediction System (AHPS) Multi-sensor Precipitation Estimates (MPE). The deficits at 60 days across Georgia, South Carolina, North Carolina, and Virginia range from 2 to 5 inches.
Across Mississippi and Alabama, some of the deficits approached 8 inches during the past 90 days, with 6 inch deficits during the past 60 days. Severe drought (D2) was introduces to Baldwin and Mobile counties in southern Alabama, while D1 (moderate drought) was expanded across western and north-central Alabama. Many unmanaged streams across Alabama are indicated D1 conditions and a few in the D2 range. D0 was expanded across northern Louisiana and southern Alabama to reflect the ongoing lack of widespread precipitation. Climate Division 6 in Louisiana has had less than 50% of normal rain over the past 60 days. CPC SPI blends also indicate deepening drought across Louisiana.
Ohio and Tennessee Valleys
Rainfall during the past 7 days helped relieve a small amount of dryness across northern Indian. Just over 0.5 inch fell across the D0 area in northern Indiana and southern Michigan. Some precipitation indicators are showing dry conditions across Ohio, Pennsylvania, and West Virginia, but streamflows have remained mostly above drought thresholds. This area will be monitored for deepening dryness in the coming weeks.
Pacific Northwest
Light to moderate precipitation fell across Washington, northern Idaho, and Montana. The precipitation totals (0.5 to 2.2 inches) across northern Idaho prompted the removal of some D0. In Washington, the heaviest precipitation fell outside of areas designated as dry or in drought, but some precipitation fell across central Washington prompting a small trimming of D0.
Southern and Central Plains
Widespread rains fell across the area from Texas to Tennessee. The heaviest rains fell across the drought stricken regions of Texas, with rainfall totals exceeding 6 inches. The rains prompted anywhere from a full 1-category improvement to minor reductions in drought but not as much improvement as might be implied from the notable rainfall totals. The restrained approach in the improvement was due to the drought being primarily long-term, defined by flows in large rivers and storage in major reservoirs, both of which showed little change with the recent rains. Dry conditions continue across southeast Texas, with D0 expanding slightly.
Slightly farther north in Oklahoma, severe drought (D2) and moderate drought (D1) were trimmed along the Red River. No change was made to the drought depiction across Kansas. The latest drought report from the state of Kansas shows mostly below normal rains for the year (January 1 – October 31), but a more mixed signal during the past 30 and 60 days. Persistence was also the case for Colorado. The seasonal snowfall totals are slightly below normal, so this region will be monitored during the coming weeks.
Upper Mississippi Valley and Northern Great Plains
Temperatures across the region were above average for the past week. Despite that, reports indicate that the landscape is freezing up and very little soil moisture recharge is possible this year. Some moderate precipitation (0.5 – 1.7 inches) fell across east-central Minnesota, prompting a small reduction in D0 there, but for the most part, the long-term deficits continued to mount. Abnormal dryness (D0) was expanded across South Dakota and Minnesota to coincide with 60- and 90-days PNP of 50% or less.
Author(s):
Matthew Rosencrans, NOAA/NWS/NCEP/CPC
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