Prognostic Discussion for Long-Lead Seasonal Outlooks NWS Climate Prediction Center College Park MD 830 AM EST Thu Feb 17 2022 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS The March-April-May (MAM) 2022 temperature outlook favors above normal seasonal mean temperatures from the Southwest, across the Central and Southern Plains, to most of the eastern half of the contiguous U.S. The largest probabilities, exceeding 60 percent, for above normal temperatures are forecast across the Rio Grande Valley. Probabilities of below normal temperatures are elevated for parts of the Pacific Northwest, northern Rockies, and southeastern Alaska. The MAM 2022 precipitation outlook favors below normal seasonal precipitation amounts from southern California and the Southwest to western areas of the central and southern Great Plains, and along the Gulf Coast into the Atlantic Coast of the Southeast. Below normal precipitation is favored for coastal southern Mainland Alaska and the Alaska Panhandle. Above normal seasonal precipitation amounts are likely for parts of the Midwest, the northern Rockies, the Pacific Northwest, and much of northern and western Mainland Alaska. Equal chances (EC) are forecast for areas where seasonal mean temperatures and seasonal accumulated precipitation amounts are expected to be similar to climatological probabilities. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS Note: For Graphical Displays of the Forecast Tools Discussed Below See: http://www.cpc.ncep.noaa.gov/products/predictions/90day/tools/briefing CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS La Niña conditions persist across the equatorial Pacific Ocean, as indicated by current oceanic and atmospheric observations. In January 2021, below-average sea surface temperatures (SSTs) persisted across the central and eastern equatorial Pacific Ocean, with the latest Niño 3.4 SST temperature anomaly around -0.7 degrees C. Suppressed convection was evident in positive outgoing longwave radiation anomalies near the Date Line. Positive subsurface temperature anomalies have shifted eastward to around 110 degrees W longitude but remain at depth, while negative anomalies have contracted to the eastern Pacific. Low-level easterlies are mostly near average strength, while easterly wind anomalies were observed over parts of the western and eastern equatorial Pacific Ocean. Upper-level westerly wind anomalies were observed over the east-central equatorial Pacific Ocean. The tropical Pacific atmosphere is consistent with La Niña conditions. The North Atlantic Oscillation (NAO) is positive and forecast to remain positive into the beginning of March, increasing the chances of above normal temperatures over the eastern CONUS early in the season. PROGNOSTIC DISCUSSION OF SST FORECASTS The CPC SST consolidation for the Niño 3.4 region indicates that negative SST anomalies are likely to remain below -0.5 degrees C through MAM and then near-average from the late spring through the summer and autumn of 2022. The North American Multi Model Ensemble (NMME) mean forecast for the Niño-3.4 SST anomaly indicates a slightly slower weakening of negative SST anomalies to near -0.5 degrees C during the next six months. The official CPC/IRI ENSO outlook is for La Niña to continue into the Northern Hemisphere spring (77% chance during MAM 2022) and then transition to ENSO-neutral (56% chance during MJJ 2022). PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS Dynamical model guidance such as the North American Multi-Model Ensemble (NMME) and the Calibration, Bridging, and Merging (CBaM) version of the NMME were used through lead 5. La Niña temperature and precipitation composites and regressions based on Niño 3.4 SST anomalies were primarily relied upon for MAM and AMJ 2022. The consolidation tool, which includes both the NMME and various statistical tools as inputs, was also used, especially after the predicted transition to ENSO-neutral conditions by early summer. At longer leads, from 6 to 13 months (ASO 2022 to MAM 2023), decadal trends represented by the optimum climate normals (OCN) were a significant driver of the climate outlooks. PROGNOSTIC DISCUSSION OF OUTLOOKS - MAM 2022 TO MAM 2023 TEMPERATURE Only minor adjustments were made to the previous temperature outlooks, released in January 2021, as La Niña continues to be the major driver of the predicted climate during MAM 2022, and a transition to ENSO-neutral conditions is expected thereafter. Below normal temperatures are favored for the Pacific Northwest across parts of the Northern Rockies, consistent with current dynamical model guidance and La Niña conditions. Probabilities of above normal temperatures were increased across the Rio Grande Valley, with increased confidence of a continuing La Niña into MAM and AMJ 2022. The probabilities for above normal temperatures were increased for parts of the Northern Plains from MAM 2022 through the first several leads into autumn, supported by the NMME dynamical model forecasts, and with snow cover and soil moisture deficits over some areas impacting the MAM 2022 outlook. While the NMME dynamical model guidance favors more extensive below normal temperatures across much of Mainland Alaska, statistical tools and the CBaM tool favors more extensive above normal temperatures over central and northern Alaska. The area of enhanced probabilities of below normal temperatures is confined to southeastern Mainland Alaska and the Alaska Panhandle in the outlooks for MAM and AMJ 2022. As the leads progress through spring into summer and longer leads, above normal temperatures are favored over a greater area of Mainland Alaska related to decadal trends, as well as across much of the CONUS, especially during the summer seasons. PRECIPITATION The precipitation outlook for MAM 2022 is consistent with canonical La Niña impacts and recent model guidance. The probabilities for below normal precipitation were increased across much of the West from AMJ through JAS 2022, consistent with NMME forecasts and the consolidation tool. Areas of enhanced probabilities of above normal precipitation over parts of the Midwest and the Mid-Atlantic regions and for western Mainland Alaska from AMJ 2022 through ASO 2022 are consistent with current model guidance from the NMME and with the consolidation tool. At longer leads, the precipitation outlooks generally rely on the decadal trends and guidance from the consolidation of statistical tools. Below normal precipitation is favored over substantial areas of the western CONUS from autumn through next winter, while above normal precipitation is favored for some regions of the central and eastern CONUS at longer leads, related to decadal timescale trends. Decadal timescale trends favor below normal precipitation for the southern Alaska Panhandle through all leads. FORECASTER: Dan Collins The Climatic normals are based on conditions between 1991 and 2020, following the World Meterological Organization convention of using the most recent 3 complete decades as the climatic reference period. The probability anomalies for temperature and precipitation based on these new normals better represent shorter term climatic anomalies than the forecasts based on older normals. For a description of of the standard forecast tools - their skill- and the forecast format please see our web page at http://www.cpc.ncep.noaa.gov/products/predictions/long_range/tools.html (Use Lower Case Letters) Information on the formation of skill of the CAS forecasts may be found at: http://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/Outlook/outlook.shtm l (use lowercase letters) Notes - These climate outlooks are intended for use prior to the start of their valid period. Within any given valid period observations and short and medium range forecasts should be consulted. This set of outlooks will be superseded by the issuance of the new set next month on Mar 17 2022 1991-2020 base period means were implemented effective with the May 20, 2021 forecast release. $$