#Snowpack news: South Platte River Basin still on top in #Colorado = 124% of normal, widespread snowfall on the way for the mountains

Click on a thumbnail graphic to view a gallery of snowpack data from the NRCS.

Here’s the Westwide SNOTEL basin-filled map for December 12, 2019 from the NRCS.

Westwide SNOTEL basin-filled map December 12, 2019 via the NRCS.

From OutThereColorado.com (Spencer McKee):

According to the National Weather Service, the “inland intrusion of an atmospheric river” is making landfall in parts of California and Oregon, expected to impact upcoming weather in Colorado’s mountains and high-altitude areas of the western slope. Starting late Thursday and continuing through Sunday morning, up to two feet of snow could fall in the northern and central mountains. Snowfall is currently forecasted to hit later in the San Juans, likely dropping flakes in the 12 to 18 inch range in this region.

#Drought news: No change in depiction for #Colorado

Click on a thumbnail graphic to view a gallery of drought data from the US Drought Monitor.

Click here to go to the US Drought Monitor website. Here’s an excerpt:

This Week’s Drought Summary

The U.S. Drought Monitor week saw another round of winter storms, bringing snow to the mountainous areas of the West, northern Plains, upper Midwest, and Northeast while lower elevations of the West and parts of the South, Southeast, lower Midwest, and Mid-Atlantic regions saw rain. This week’s precipitation in the Southwest left many areas with accumulations that exceeded 300 percent of normal over the past 14-day period, leading to continued improvements in short-term dryness. Once again, precipitation in the Northwest was below normal. Many locations have received less than 25 percent of normal over the last 14 days, resulting in the expansion of abnormally dry conditions. Meanwhile, another dry week in the Southern Plains and below-normal rainfall in the South and Southeast led to expansions in pockets of abnormal dryness and drought…

High Plains

Last week’s weather brought continued dryness to the abnormally dry and drought areas of south-central Nebraska, Kansas and eastern Colorado. In Kansas, where moisture deficits have been present for more than three months, abnormal dryness (D0), moderate drought (D1), and severe drought (D2) were expanded to reflect the increasing dryness and its impact on winter wheat. The map was unchanged this week for the remainder of the region…

West

Another week of above-normal rainfall and mountain snow led to continued improvements in the Southwest. In California and Nevada, rainfall over the last three weeks has helped to make up for the slow start to the water year, resulting in the removal of the abnormal dryness (D0) depiction across most of the state. Pockets of D0 remain in areas that missed the heaviest precipitation or where station data indicate below-normal snow. In the Four Corners states, the map depiction strives to balance the effect of the recent precipitation with the failure of the monsoon. Changes include a broad 1-category improvement across southern and western Arizona, western Utah, and western New Mexico. The heavy black line separating drought impact designations was expanded to delineate areas that are experiencing both short- (less than 6 months) and long-term (greater than 6 months) deficits. For example, the designation across southern and western Arizona is “L”, indicating that deficits are only present at longer time scales and in indicators such groundwater and root zone soil moisture, whereas the designation in eastern Colorado is “S”, indicating more seasonal deficits and impacts to indicators such as surface soil moisture and streamflow…

South

The South once again saw a mixture of degradations and improvements. Improvements were limited to central Texas, where last week’s rainfall, in excess of 300 percent of normal, resulted in a general one-category improvement. Meanwhile, the eastern and southern parts of the state continued to dry out with expansions to areas of abnormal dryness (D0) and moderate (D1) and severe (D2) drought. The heavy black line separating drought impact designations was shifted eastward in south Texas to reflect that this area is also experiencing dryness at longer (more than 6 months) time scales. Eastern Oklahoma also saw degradations with an expansion of D0 as dryness, extending back to September, continued. This dryness comes at a vital time in winter crop cycles, and a continued lack of moisture may cause impacts later. Other degradations include the expansion of D0 and/or D1 in southwest Arkansas, Louisiana, and southwest Mississippi…

Looking Ahead

The National Weather Service Weather Prediction Center forecast for the remainder of the week calls for moderate to heavy mountain snows extending from the Pacific Northwest to the north-central Great Basin and Rockies. Meanwhile, parts of the northern High Plains, Upper Mississippi Valley, and upper Great Lakes are expected to see snow. As this storm moves eastward over the weekend, the Southeast, Tennessee Valley, and Mid-Atlantic will see rain, while mixed precipitation is expected in the Northeast. Dry conditions are expected in the Southwest, Southern Plains, and lower Mississippi River Basin.

Moving into next week, the Climate Prediction Center 6 to 10 day outlook (valid December 16-20) favors above-normal temperatures for the central and northern coast of California; parts of the Pacific Northwest, Southwest, and Central Plains regions; and the Florida Peninsula. Areas with increased chances for below-normal temperatures include parts of the Ohio and Tennessee Valleys and the Northeast region. Precipitation is likely to be above normal over the Pacific Northwest, parts of northern California, and from the Southern Plains, across the Southeast, and into the Mid-Atlantic region.

The latest #ENSO Diagnostic Discussion is hot off the presses from the #Climate Prediction Center

Click here to read the discussion:

EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society 12 December 2019
ENSO Alert System Status: Not Active

Synopsis: ENSO-neutral is favored during the Northern Hemisphere winter 2019-20 (70% chance), continuing through spring 2020 (~65% chance).

Above-average sea surface temperatures (SSTs) were observed in the central tropical Pacific Ocean during November, with regions of above and below average SSTs observed farther east. In the most recent week, the SST indices were near average in the east-central and eastern Niño regions (+0.1°C to +0.3°C) and were above average in the westernmost Niño-4 region (+0.9°C). The equatorial subsurface temperature anomalies (averaged across 180°-100°W) returned to near zero during the month, reflecting the progression of Kelvin waves to the east. The low-level winds were near average during November, while easterly upper-level wind anomalies were observed over the western Pacific. Finally, tropical convection was suppressed near and east of the Date Line and also over Indonesia, and somewhat enhanced over the western Pacific northeast of Papua New Guinea. The overall oceanic and atmospheric system was consistent with ENSO-neutral.

The majority of models in the IRI/CPC plume continue to favor ENSO-neutral (Niño-3.4 index between -0.5°C and +0.5°C) through the Northern Hemisphere summer. Many dynamical model forecasts suggest Niño-3.4 SST index values may remain near +0.5°C into December before decreasing toward zero. Forecasters agree with this consensus and believe the chances for El Niño to be 25-30% during the winter and spring. In summary, ENSO-neutral is favored during the Northern Hemisphere winter 2019-20 (70% chance), continuing through spring 2020 (~65% chance; click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).