February - April 2014

Outlook Graphic: PNG   PDF 

Latest Seasonal Assessment - Since the previous outlook issued during mid-December, a large expansion of drought occurred across the Pacific Northwest with drought intensification throughout California. These drought changes are associated with a lack of precipitation along the West Coast during a wet time of year. Drought conditions generally remained steady during the past month across the Midwest and Great Plains, while abnormal dryness (D0 depicted on the USDM) is nearly eliminated from the Southeast.

The drought outlook valid from January 16 – April 30, 2014 is based primarily on short-, medium-, and long-range forecasts, and initial conditions. Drought is expected to worsen during the latter half of January across the Pacific Northwest. The poor start to the wet season with large precipitation deficits and very low snow-water equivalent values is likely to result in a continuation of drought through the end of April. Therefore, drought persistence is forecast for the Pacific Northwest. Forecast confidence is high for drought persistence or intensification across California due to the extremely dry initial conditions (snow-water equivalent values in the Sierra Nevada Mountains in the lowest 5th percentile as of mid-January) and below-median precipitation favored in the CPC monthly and seasonal precipitation outlooks. Meanwhile, across the interior West and Southwest, drought persistence or development is consistent with the CPC monthly and seasonal precipitation outlooks.

Forecast confidence is low across the central and southern Great Plains due to weak signals among the precipitation tools, but persistence is most likely. Persistence is forecast across northwest Iowa, southern Minnesota, and Wisconsin, while prospects for improvement increase across southeast Iowa, northern Missouri, and Illinois. Development forecast across west Texas and the western Gulf Coast is based on short-term precipitation deficits and some dry signals among the monthly or seasonal precipitation tools.

The eastern U.S. is mostly drought-free with long-term drought likely to end during the outlook period across the Northeast. Despite the CPC seasonal outlook calling for enhanced odds of below-median precipitation, development is not forecast across most of the Southeast due to recent heavy rainfall. However, development is forecast across parts of the Florida peninsula where rainfall amounts were lighter.

Removal is forecast for the small drought area across east-central Alaska, but abnormal dryness may linger into the spring. Removal/improvement of drought is expected across Hawaii early during the outlook period.

Tools used in the U.S. Seasonal Drought Outlook (SDO) included the official Climate Prediction Center (CPC) temperature and precipitation outlooks for February 2014, the long lead forecast for February - April 2014, various short- and medium-range forecasts and models such as the 5-day and 7-day precipitation totals from the Weather Prediction Center, 6-10 day and 8-14 day CPC forecasts, the NAEFS precipitation outlooks, the soil moisture tools based on the Constructed Analog on Soil (CAS) moisture, dynamical models (CFSv2, NMME, and IMME), the 384-hour total precipitation forecasts from several runs of the GFS, the four-month Palmer drought termination and amelioration probabilities, climatology, and initial conditions. ENSO conditions continue to be and are forecast to remain neutral.

A persistent, upper-level ridge across the east Pacific resulted in an unusually dry start to the wet season for the West Coast. According to AHPS, 90-day precipitation deficits exceed 16 inches across coastal areas of northern California and the Pacific Northwest along with the Sierras. Winter is a critical time to build an adequate snowpack for water resources across these areas. The Sierra Nevada Mountains have a near historically low snowpack for this time of year. According to the Western Regional Climate Center, river basin snow water content values as of January 13 are running at the lowest 5th percentile across the Sierras and southern Cascades. Model guidance on January 15 indicates that a highly amplified ridge will remain anchored along the West Coast during the next two weeks, which strongly favors little or no precipitation. Due to the extremely dry initial conditions and likely continuation of dry weather during the remainder of January, persistence or intensification of drought is forecast for the Pacific Northwest and California. Even if a pattern change with much-needed precipitation occurs along the West Coast during February, precipitation deficits and an inadequate snowpack are anticipated to persist throughout the remainder of this outlook period. Forecast confidence is lower across the Pacific Northwest than California where the CPC seasonal outlook calls for enhanced odds of below-median precipitation.
Forecast confidence ranges from high across California to moderate across the Pacific Northwest.

Forecast reasoning for the ongoing drought areas of the West and expansion of drought across the Southwest is similar to the West Coast addressed in the previous paragraph. Although 90-day precipitation deficits are not as extreme across the interior West, river basin snow water content values are running below-average across most of Idaho, Nevada, Utah, and the Southwest. The persistent ridge along the West Coast is likely to result in little or no precipitation during the next two weeks across these areas. The CPC seasonal precipitation outlook calls for enhanced odds for below-median precipitation across the Southwest with equal chances to the north across the northern Great Basin. A lack of a wet signal among the tools and initially dry conditions support persistence or development of drought across the interior West and Southwest. In addition, enhanced odds for above normal temperatures forecast during FMA raises the chances for an early season snow melt.
Forecast confidence for the interior West and Southwest is moderate.

The CPC seasonal outlook calls for equal chances of above, near, or below-median precipitation across the central and southern Great Plains during FMA. The upstream ridge along the West Coast is likely to maintain a dry pattern across the central and southern Great Plains at least through the next ten days. Persistence is forecast across the central and southern Great Plains, but forecast confidence is tempered due to weak signals among the seasonal precipitation tools and increasing wet climatology during April.
Forecast confidence for the central and southern Great Plains is low.

Persistence is the most likely category across the ongoing drought areas of Texas but confidence is low due to weak signals among the seasonal precipitation tools. 30-day precipitation deficits support a small expansion of drought across west and southeast Texas. Also, the CPC February outlook calls for enhanced odds for below-median precipitation across southeast Texas. Development is not forecast across south Texas due to 30-day precipitation surpluses for this area. Meanwhile, development across southern Louisiana is based on increasing short-term precipitation deficits along with increased chances of below-median precipitation in CPC’s monthly and seasonal precipitation outlooks.
Forecast confidence for Texas and southern Louisiana is low.

Drought coverage and intensity remained steady during the past month across the Midwest which is typical for winter as soil moisture recharge is limited. Since precipitation begins to increase during the early spring across southeast Iowa, Missouri, and Illinois, drought removal or improvement (where drought levels are D2) are forecast for these areas. Climatology is slightly drier to the north across Minnesota and Wisconsin where persistence is forecast.
Forecast confidence for the Midwest is low.

Long-term moderate drought conditions continue across small parts of the Northeast. Precipitation averaged near to above-normal during the past 60 days across the Northeast with only long-term drought indicators supporting the current drought status. Since the drought level is moderate and the tools offer no dry signal, drought is expected to end before the end of April across the Northeast.
Forecast confidence for the Northeast is high.

A small area of moderate drought continues in east-central Alaska. Since the 6-10 and 8-14 day outlooks favor above-median precipitation for Alaska and equal chances are forecast by the CPC seasonal outlook, drought removal is most likely.
Forecast confidence for Alaska is high.

Since the CPC February precipitation outlook favors above-median precipitation, improvement or removal of drought is forecast across the Hawaiian Islands. It should be noted that precipitation typically decreases later during this outlook period.
Forecast confidence for Hawaii is high.