FGUS75 KABQ 072009 ESFABQ NMC001-003-005>007-009-011-019-021-027-028-031-033-037-039-041- 043-045-047-049-053-055-057-059-061-150600- Probabilistic Hydrologic Outlook National Weather Service Albuquerque NM 208 PM MDT Thu Apr 7 2022 ...BELOW NORMAL FLOOD RISK FOR NEW MEXICO... ...EXISTING CONDITIONS... The 2020-2021 Water Year suffered from a failure of the 2020 Monsoon and persistent drought conditions. Lackluster snowfall accumulation during the 2020-2021 winter drove further degradation of drought throughout the state, leaving over 50% of the state under Exceptional Drought (D4) conditions. This was somewhat alleviated by a successful 2021 drought season. Despite midsummer gains, NM went into a fall and winter season defined by La Nina conditions present for the second year in a row. ...PRECIPITATION... Water Year 2021-2022 has been very dry so far, especially for the southern half of the state. October 2021 began with some promising spots of 2 inches of precipitation in the Sangre de Cristo Mountains and in McKinley county. In much of the southern half of the state however, precipitation amounts were 0.3 inch or less. November saw these conditions worsen with the eastern half of the state receiving 0.1 inch or less of precipitation and no location in the state receiving anywhere near the 30 year normals for precipitation in November. December brought some relief to the northwestern corner of the state in a series of snow and rain events but the eastern half of the state continued to be starved for moisture. By the end of 2021, the overwhelming majority of the state was in the 50% or less of the 30 year normals for precipitation, with only the northwestern corner of the state in good standing due to a wet december. Progressing into January 2020, the overall trend was one of decreasing precipitation totals for most of New Mexico with pockets of above normal precipitation over some of the higher terrain in the State. As the year progressed beyond January we saw a strengthening pattern of precipitation in the higher elevations in the north with the rest of the state largely suffering from well below normal precipitation. ...SNOWPACK... The accumulation of snowpack over the Southern Rockies and southern New Mexico started later than normal with the first significant snow accumulation not occurring until around December 9th. As discussed above, precipitation events generally continued through meteorological winter in higher elevations, although the liquid equivalent in these events began to taper down through the winter. Basins in the northern part of the state climbed up to near normal (slightly above or below in most cases)around January 1st. As the winter progressed a pattern of northern basins being within 10-20% of normal and southern basins being well below normal began to develop and has persisted through the spring. Climatologically, basins in southern New Mexico tend to see their peak SWE values by early-March while basins further north reach their climatological peak later in March or the first half of April. As of April 7 2022, SWE percent of normal values in New Mexico are below: Rio Chama River Basin 87% Upper Rio Grande Basin 76% Canadian River Basins 79% Jemez River Basin 82% San Francisco River Basin 22% Gila River Basin 2% Mimbres River Basin 0% Pecos River Basin 73% Cimarron River Basin 103% Zuni/Bluewater Basin 0% Rio Hondo Basin 3% Chuska Mountains 52% In Colorado: San Juan River Headwaters 88% Animas River Basin 89% ...RESERVOIR SUMMARY... Due to below normal runoff over the past two years, overall reservoir conditions throughout the state are generally below normal seasonal storages, with the relatively small Brantley reservoir being the exception as its capacity is at 107% of the 30 year median. Reservoirs on the Rio Grande are uniformly below normal with Elephant Butte at 10.6% of capacity and El Vado and Caballo both at 4.8% of capacity. The storage at both reservoirs is below the Article VII requirements of the Rio Grande Compact and therefore storage upstream of Elephant Butte is unlikely to be permitted. On other river systems, storage varies. Navajo Dam on the San Juan River is currently at 52.5% of normal storage. The Ute reservoir on the Canadian River is at 35.2% and reservoirs on the Pecos River vary from 15.7% to 107% at the Brantley reservoir. All reservoirs in New Mexico have adequate flood storage space. ...STREAMFLOW CONDITIONS AND RUNOFF FORECASTS... Streamflow conditions over northern and central New Mexico vary widely, reflecting a relatively healthy 2021 monsoon season but an exceptionally dry fall and winter with spatial disparities in winter precipitation. Many of the natural flowing basins in the north central part of the state are seeing normal seasonal streamflow values as of April 7. The Pecos, Canadian and Cimarron rivers are showing lower flows, generally in the 25th percentile or less of historical records. The Gila/San Francisco rivers as well as the San Juan/Animas rivers are in the 25th percentile or less. NWS River Forecast Centers, in conjunction with our partners in the NRCS, USACE, and the USBR, produce seasonal streamflow forecasts for selected river locations and basins in New Mexico. These forecasts are based on hydrologic conditions as of the first of the month and may not reflect current trends and forecasts. Seasonal runoff forecasts in New Mexico are all below normal. This is primarily due to below normal SWE values in combination with dry soil moisture values that must be replenished first by the snowmelt. With snowpack levels running slightly below normal in the best cases we can expect mediocre replenishment of streamflows from the spring melt. These outlooks are based on the available SWE within the river basins and climatologically expected conditions at runoff. Departures from climatological conditions at runoff (such as heavy rainfall or a loss of SWE before the normal melt out time) may change seasonal runoff volumes. Another factor that may impact seasonal runoff volumes will be depleted soil moisture values in the deeper layers of the top soil due to the prolonged drought. ...DROUGHT... Going into the fall and winter Drought conditions reflected a relatively healthy 2021 Monsoon season with the October 5 map showing 16% of the state under D3 (extreme drought) and no areas of D4 (exceptional drought). The worst drought conditions were confined to the northwest and southwest portions of the state. Due to an exceptionally dry and warm fall and winter drought conditions throughout the state have degraded severely. Currently 47% of the state is under D3-D4 with 6% under D4. Extreme drought persists in the northwest and southwest but the eastern half of the state has seen negligible precipitation for months and most of it is currently under D3 or D4. The drought status for New Mexico is re-evaluated weekly and can be found at the National Drought Mitigation Center website at http://droughtmonitor.unl.edu. ...CLIMATE OUTLOOK... The NWS/Climate Prediction Center anticipates that La Nina conditions will persist through Spring of 2019. Currently the chances for returning to an ENSO neutral condition are about even with remaining in a weak La Nina pattern through the summer. Since January, monthly issuances of climate outlooks have shown a strengthening trend in the La Nina signal and a weakening trend in both the ENSO neutral and El Nino conditions, raising the possibility of a third year in a row of La Nina conditions. These conditions are generally associated with a warmer drier climate and could aggravate ongoing drought and water supply concerns. The temperature outlook for March through May for New Mexico as well as the Southern Rockies indicates strong probabilities of above normal temperatures and below normal precipitation. These outlooks are issued monthly with the next outlook to be issued on March 19th. Outlooks can be found at the NWS/CPC website at http://www.cpc.ncep.noaa.gov. ...SPRING FLOOD OUTLOOK... Given the current hydrometeorological and antecedent soil and streamflow conditions, most basins in New Mexico have a below normal risk of spring flooding. Spring flooding related to snowmelt is uncommon on larger rivers in New Mexico, especially after the construction of the larger dams on the mainstem rivers. The primary factors in this assessment are the normal below normal SWE values, below normal deep-layer soil moisture values, and current hydrometeorological trends. While the Rio Grande can see high flows from snowmelt, flooding is rare. The combination of low soil moisture and below normal SWE give a below normal risk of flooding on the Rio Grande. The Pecos River typically does not experience snowmelt flooding as well, and with below normal SWE values in the headwaters the risk of flooding is very low. The Canadian, San Francisco, Rio Hondo, and Gila Basins typically do not see flooding due to spring runoff and normally experience flooding related to heavy rainfall or mid-winter rain-on-snow Events. While it is too early to forecast the monsoon season with any reasonable accuracy, the lack of any appreciable snowpack in these basins reduces the risk of flooding. The NWS Albuquerque Hydrologic Service Area (HSA) is serviced by three River Forecast Centers: West Gulf RFC (Fort Worth, TX), Arkansas-Red Basin RFC (Tulsa, OK), and the Colorado River Basin RFC (Salt Lake City, UT). These RFCs issue a variety of hydrologic forecast products during the year. Further products and current information can be found at the following locations: https://www.weather.gov/wgrfc https://www.weather.gov/abrfc https://www.cbrfc.noaa.gov You can also find additional weather and water products and forecasts at the NWS Albuquerque website at: https://www.weather.gov/abq For questions or comments about this outlook, you can contact Andrew Mangham, Senior Service Hydrologist, at 505-244-9150 x 228 or via e- mail at andrew.mangham@noaa.gov. $$ ANM