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08/09/2022, 4:52 am EDT

JUL/AUG/SEP 2022 U.S. Wind and Solar Verification/Forecast Report

EXPERIMENTAL Zonal/Meridional Wind Anomaly Forecast EXPERIMENTAL Specific Humidity Anomaly Forecast VERIFICATION/Climate Summary for July 2022 Valid: August through September 2022 Climate discussion: Since 2013, the evolution of a persistent large area of (mostly) anomalous warm surface/subsurface water in the middle latitudes (of both hemispheres) and somewhat independent of ENSO is observed. The first notable warm zone was the Northeast Pacific Marine Heatwave also known as the “warm blob”. The “warm blob” originated in the northeast Pacific surface and to depths of 300 meters in 2013. The unexplained large mass of warm water was discovered primarily due to the alteration of wildlife across the Pacific including bird migration and various fisheries. However, later research revealed this large mass of warm ocean water was influencing climate. The “warm blob” also warmed the atmosphere to create anomalous high-pressure ridging which reached across Alaska to Siberia and helped to create the “polar vortex winter” of 2013-14 with similarities the following winter. During the past nearly 10 years, this feature has been responsible for anomalous high-pressure ridging affecting western North America contributing to the long-term drought in California. The “warm blob” review is provided due to the evolution of another large mass of very warm surface water during the middle third of 2022 directly impacting Clearway Energy. The new area of anomalous warm SSTA (Fig. 1) is on either side of Baja California and extends well offshore and has recently expanded northward along the U.S. West Coast. Presence of this large mass of anomalous warm water has increased low-level atmosphere moisture to help make the 2022 wet monsoon season stronger. Of course, the attendant thunderstorm activity and increased cloud cover affects most of Clearway Energy solar stations across the southwest quadrant of the U.S. Fig. 1: Generation of a new “warm blob” of SSTA has occurred off the California and Baja California Coast during the 2022 warm season. July 2022 verification: The July 2022 U.S. zonal/meridional wind anomaly verification indicates minimal west-to-east (or east-to-west) wind direction anomalies (Fig. 2). The exception is across the Great Lakes region and Ontario where above normal westerlies were observed. However, meridional wind anomalies were stronger (Fig. 3) featuring above normal southerlies across much of California to Utah and across all of the Southeast U.S. The stronger southerlies were related to a stronger than normal southerly moisture feed associated with the Southwest U.S. Monsoon across California and stronger than normal southerlies on the backside of the “Bermuda high-pressure ridge” in the Southeast. Generally, wind was lighter than normal across a key wind generating area from the southwest Great Plains into western Texas. As compared to the July 2022 forecast, zonal wind was close to normal across most of the U.S. whereas the forecast was for below normal zonal wind speeds (Fig. 4). The meridional wind speed forecast was correct for California and had the right idea with below normal wind speed forecasts for the southwest Great Plains into Texas but not strong enough across the southeast quadrant of the U.S. (Fig. 5). Fig. 2-3: Verification of the July 2022 zonal and meridional wind anomalies. Fig. 4-5: The Climate Impact Company initial July 2022 zonal and meridional wind anomaly forecast. Not surprisingly, given this year’s robust wet monsoon, specific humidity (SH) at both 850 MB (5,000 feet) and 300 MB (30,000 feet) was substantially above normal for July. High level SH at 850 MB (Fig. 6) implies above normal presence of convective clouds (thunderstorms) while cirrus canopies from vast thunderstorm development produced widespread above normal SH at 300 MB (Fig. 7). The July 2022 forecast was reasonably accurate at forecasting above normal SH at 850 MB although not to the full aerial extent observed to the north across the Interior Northwest States (Fig. 8). The 300 MB SH forecast was much-underdone compared to verification across the important California/Southwest U.S. sector to Clearway Energy (Fig. 9). Fig. 6-7: Verification of the July 2022 low-level (850 MB) and high-level (300 MB) specific humidity to identify cloud presence.    Fig. 8-9: The Climate Impact Company initial July 2022 850 MB and 300 MB specific humidity anomaly forecast. August/September 2022 wind forecast: August is already underway and consulting operational forecasts valid through 15 days is recommended for Clearway Energy. The Climate Impact Company constructed analog (CIC-CA) forecast projects below normal wind speeds across the Southwest U.S. during August and near normal across California (Fig. 10-11). The below normal wind speed is due the continuation of the wet monsoon which lowers thermal gradient in the lower atmosphere to drive wind speeds. Wind speeds are stronger than normal across Texas, especially near the coast in response to possible tropical cyclone activity later this month. In the south-to-east Great Plains wind speeds are below normal due to presence of dry/hot high-pressure. Note the above normal wind speed forecast across the Southeast U.S. and just-along the East Coast all in response to late August tropical cyclone risk. The September forecast maintains below normal wind speeds across the Interior Southwest U.S. likely related to the wet monsoon (Fig. 12-13). The CIC-CA forecast projects normal wind speeds across California in September. Interestingly, zonal wind speeds are stronger than normal across the East-central U.S. in September while meridional wind speeds are somewhat weaker than normal. Favoring zonal flow implies passing frontal systems are weaker than normal. Above normal wind speeds are forecast across the Southeast U.S. to Mid-Atlantic Coast in September likely due to tropical cyclone activity risk. Coastal Texas is more windy than normal in September while wind generating areas across western Texas to the southwest Great Plains are less windy than normal. Fig. 10-11: Experimental CIC-CA U.S. forecast of zonal and meridional wind anomalies for August 2022. Fig. 12-13: Experimental CIC-CA U.S. forecast of zonal and meridional wind anomalies for September 2022. August and September 2022 solar discussion: In August, the wet monsoon in the Southwest U.S. continues (Fig. 14) although the CIC-CA forecast may not be as strong as current operational models indicate. While the low-level cloudiness is abundant, high-level cloud is likely higher than indicated by the CIC-CA forecast for August (Fig. 15). Cloud cover forecasts for California are below normal both in lower and high levels of the atmosphere in August. One cautionary note…as mentioned earlier in this report, the SSTA pattern off the California and Baja California Coasts is somewhat warmer than normal and able to sustain for longer than normal any tropical system that may travel northward out of the East Pacific tropics. The low-level cloud forecast is above normal for East Texas/Louisiana likely in response to tropical cyclone risk. Southern Florida is also at risk of above normal cloud cover due to tropical activity. In September, there is concern in regard to expanding Central U.S. drought. The cloud cover forecasts imply widespread above normal solar intensity due to below normal low-level and high-level cloudiness (Fig. 16-17). Similarly, much above normal solar energy is forecast across most of the West U.S. except for parts of Arizona and New Mexico where the wet monsoon pattern lingers. Fig. 14-15: Experimental CIC-CA U.S. forecast of 850 and 300 MB specific humidity for August 2022 to estimate cloud cover. Fig. 16-17: Experimental CIC-CA U.S. forecast of 850 and 300 MB specific humidity for September 2022 to estimate cloud cover. Forecast methodology: The climate forecasts presented are based on a constructed analog. The Climate Impact Company constructed analog is based on regional SSTA plus ENSO and also considers soil moisture (during summer) and snow cover (during winter). Clearway Energy recommendation: The forecasts provided are experimental constructed analog projections. To engage in real-time forecasts of daily wind and solar projections to ensure highest accuracy, at least through the next 15 days, is recommended for Clearway Energy by Climate Impact Company.
07/08/2022, 10:05 am EDT

Wind and Solar Forecast for July through September 2022

EXPERIMENTAL Zonal/Meridional Wind Anomaly Forecast EXPERIMENTAL Specific Humidity Anomaly Forecast Valid: July through September 2022 Discussion: This the first full-throttle experimental zonal/meridional wind speed and 850 MB/300 MB specific humidity forecast issued to Clearway Energy. The intent is to estimate national wind speed anomalies for wind-driven power generation and low and high cloud cover for solar power generation. The forecast is based on a constructed analog (CA). The maps/data generated are from the Physical Sciences Division (PSD) at the National Climate Data Center (NCDC) using the best available parameters to attain the identified goal. The CA process is proprietary to Climate Impact Company. The methodology varies depending on the prevailing climate pattern. However, in general the CA process used for this forecast is driven by global regional sea surface temperature anomalies (SSTA), soil moisture observations and trend and adding an optimum climate normal (OCN). The wind speed forecast is based on available data for zonal (west-to-east/east-to-west) and meridional (north-to-south/south-to-north) vectors. The solar forecast is based on specific humidity at 850 MB (5,000 feet) and 300 MB (30,000 feet). Preferred is relative humidity (RH) at each mandatory pressure level. However, RH data is not available for this forecast. The intent is to identify above/below normal risk of cloudiness where cumulus (850 MB) and cirrus (300 MB) clouds form. The forecast includes CA graphics for July through September and an attendant forecast discussion. Operational forecasts are recommended for month-1 (July) since we’re 8 days into the month and the CA forecast is experimental in character. Please inform Climate Impact Company in regard to interest in operational solar and wind forecasts. Wind July 2022 Fig. 1-2: Experimental CIC-CA U.S. forecast of zonal and meridional wind anomalies for July 2022. July 2022 discussion: The CA forecast indicates the prevailing upper air pattern for mid-summer across North America features an area of high-pressure centered over Western Ontario. Operational forecasts indicate this pattern is likely although likely delayed until the second half of July. General high pressure supports below normal zonal and meridional wind speeds during July for the Great Plains to Texas and across most of the East U.S. However, above normal zonal wind speeds (west-to-east) are likely across northern California to the south of an occasional low-pressure area off the Northwest U.S. Coast and also out of the south related to an active Southwest U.S. mid-summer monsoon. However, Southern California can expect below normal wind speeds. Wind August 2022 Fig. 3-4: Experimental CIC-CA U.S. forecast of zonal and meridional wind anomalies for August 2022. August 2022 discussion: During late meteorological summer, the upper ridge pattern over Ontario in July shifts east to Newfoundland (and eastward). An upper ridge pattern develops over the West Coast. In-between a “col” develops suggesting a possible corridor of tropical risk into the Gulf of Mexico from the Caribbean Sea. During August, zonal wind speed anomalies are generally above normal across the Interior West and the Southeast U.S. to the Carolinas. Generally, the wind speeds are east-to-west and related to the Southwest U.S. Wet Monsoon (in the West) and possible tropical threats across the southeast quadrant of the U.S. The meridional wind speed anomalies are also stronger than normal from Texas to the Southeast U.S. (southerlies) plus central coastal California (southerlies). Wind September 2022 Fig. 5-6: Experimental CIC-CA U.S. forecast of zonal and meridional wind anomalies for September 2022. September 2022 discussion: The upper air forecast for September 2022 is sprawling upper-level high-pressure from the Southwest U.S. to Nova Scotia. The occasional “col” (split between high-pressure centers) is in the Gulf States. This location is a tropical cyclone risk area in September. The zonal wind anomaly forecast indicates above normal east-to-west character across southern Louisiana likely related to a tropical risk. Zonal wind anomalies are also above normal in the Missouri Valley plus the Upper Midwest States. Below normal zonal wind anomalies are indicated in southern California and the Northeast Corridor. Not surprisingly, give a tropical risk, the meridional wind anomalies are stronger than normal through the East and also along the West Coast (southerlies) in September. Great Plains meridional wind anomalies are below normal across the entire Great Plains during late warm season. Solar July 2022 Fig. 7-8: Experimental CIC-CA U.S. forecast of specific humidity at 850 MB and 300 MB for July 2022. July 2022 discussion: We’re using specific humidity as the preferred relative humidity parameter is not available. Consequently, this forecast is truly experimental. (Experimental = Requires a period of verification to fully validate). Both the CA and operational forecasts indicate an active Southwest U.S. wet monsoon in July. The core of that risk shifts from New Mexico earlier this summer to Arizona and Southern California for July. Operational models confirm this westward shift. Indicated is above normal risk of convective clouds suppressing sunlight for the southern half of California and all of Arizona in July. The Arizona forecast is most confident. Positive values are also indicated across Louisiana and the Great Lakes region. The Louisiana forecast is confident; less so the Great Lakes where high-pressure is forecast to build. At 300 MB where cirrus is dominant, only the Missouri Valley is forecast to produce sunlight suppressing cloudiness. Solar August 2022 Fig. 9-10: Experimental CIC-CA U.S. forecast of specific humidity at 850 MB and 300 MB for August 2022. August 2022 discussion: The wind speed anomaly forecast suggests above normal risk of tropical risk to the Southeast U.S. in August. However, specific humidity at 850 MB is generally near normal in August while at 300 MB there is an absence of high cloud risk based on the CA forecast. Above normal cloud cover at 850 MB and 300 MB is projected across the Northeast Corridor where above normal rainfall is indicated. The only other anomalous cloud risk area remains over the Southwest U.S. Desert where the wet monsoon pattern stays active. Solar September 2022 Fig. 11-12: Experimental CIC-CA U.S. forecast of specific humidity at 850 MB and 300 MB for September 2022. September 2022 discussion: Except for the south coast of California where convective clouds are above normal during September, most of the Interior West and Southwest has a remarkably sunnier than normal month of September. Just-the-opposite is true of the Mid-south/Southeast to Midwest/Northeast U.S. where cloudiness is above normal in both the lower and upper atmosphere strongly inhibiting potential sunlight.    
07/06/2022, 8:03 pm EDT

May/June 2022 Wind and Solar Report

May and June 2022 U.S. Verification Report Fig. 1: May 2022 observed zonal wind anomalies for the U.S. May 2022 wind discussion: The prevailing upper air pattern during May featured two well-structured pressure systems: 1.) A robust semi-permanent upper-level low-pressure trough over the Northwest U.S. and 2.) a compensating semi-permanent high-pressure upper-ridge ridge positioned over New England. As a result, the Central and East U.S. were very warm while Northwest States were unusually chilly. The Northwest was wet during May due to the upper trough while the Southeast States were wet due to an abundance of subtropical moisture. The upper air pattern forced stronger-than-normal wind speeds across the Interior West and across Montana during May (Fig. 1). The stronger westerlies were present due to a stronger-than-normal Pacific jet stream extending inland in-between the Northwest trough and high-pressure ridge west of California. Zonal wind speeds were also stronger than normal helping to inspire an early fire season across New Mexico. Beneath high-pressure, the Northeast observed lighter than normal zonal wind speeds during May. Meridional wind anomalies were stronger-than-normal across the northwest Gulf States, East-central U.S. and Upper Midwest States due to southerly flow around the semi-permanent high-pressure cell over New England (Fig. 2). Otherwise, regions of anomalous meridional wind speeds were limited. Fig. 2: May 2022 observed meridional wind anomalies for the U.S. Fig. 3: June 2022 observed zonal wind anomalies for the U.S. June 2022 wind discussion: During June 2022 an upper-level semi-permanent high-pressure ridge was centered over the Missouri Valley. The high-pressure ridge inspired anomalous heat and dryness for the Great Plains into the Southeast U.S. and also an emerging East-central U.S. drought concern added to the vast drought already in-place for the West U.S., western Great Plains and Texas. Although smaller in aerial coverage but just as intense an upper trough resided over Western Ontario for the first month of meteorological summer. The pressure systems described were causal to the dominant anomalous zonal wind pattern across the U.S. in June. An area of stronger-than-normal west wind stretched across the northern Great Plains to the Great Lakes region with strongest intensity in northeast Minnesota (Fig. 3). The only other area experiencing stronger-than-normal zonal wind was along the upper Texas Coast where easterlies around the high-pressure to the north were intact. Elsewhere, zonal wind was below normal speeds. The Southwest U.S. into California observed lighter zonal wind compared to normal. Most of the Mid-south States to the Interior Southeast U.S. also observed below normal zonal wind speeds primarily due to the presence of high-pressure. Meridional wind anomalies were mixed in June 2022. Stronger-than-normal wind speeds were observed across the Northwest States but with both south (ahead of cold fronts) and north (after fronts passed) catalysts (Fig. 4). For a similar reason, north and south component wind speeds were stronger than normal due to vigorous cold fronts moving across the Upper Midwest States. Once again, due to presence of high-pressure, Southern U.S. meridional wind speed anomalies were near to lighter than normal. Fig. 4: June 2022 observed meridional wind anomalies for the U.S. Please note: Verification of Climate Impact Company forecasts begin with the August report. Fig. 5: May 2022 observed 850 MB (relative humidity) anomalies for the U.S. May 2022 solar discussion: During the warm season (MAY-SEP) interest is primarily with low clouds (5,000 feet) and high clouds (30,000 feet). The mandatory levels of the atmosphere to evaluate relative humidity at these altitudes is 850 and 300 MB. At 850 MB, all low clouds (except stratus) are accounted for by RH at this level. Stratus is more common during the cold season when actual precipitation is added to the solar analysis. At 300 MB the cirrus cloud type is evaluated. Of course, low clouds at 850 MB parallel where precipitation was most buoyant in May…the Northwest States (Fig. 5). Where high-pressure was more dominant atmospheric subsidence ruled and below normal low clouds were observed across the Southwest U.S. and New England during May. The storm track was energetic along the U.S./Canada border in May. Consequently, above normal high clouds were present lowering sunlight potential (Fig. 6). However, high-pressure dominated the Southern States where high clouds were absent leading to above normal sunlight strength. Overall, sunlight intensity was above normal across the southern 2/3 of California to the southern Continental Divide and across Texas to Louisiana during May 2022. Fig. 6: May 2022 observed 300 MB (relative humidity) anomalies for the U.S. Fig. 7: June 2022 observed 850 MB (relative humidity) anomalies for the U.S. June 2022 solar discussion: During early meteorological summer, high-pressure caused widespread low relative humidity at the 850 MB level for the Central and East U.S. (Fig. 7). Precipitation was well below normal and sunlight intensity much above normal in this region. Cloudiness on occasion caused by the early wet monsoon brought showers/thundershowers to the Southwest U.S. causing June sunlight intensity to register below normal for this sector (important to Clearway Energy). The Southwest U.S. monsoon is convective in character and also leads to above normal high cloudiness mostly centered on New Mexico to Nebraska during June (Fig. 8). Conversely, an upper-level ridge pattern in the East yielded limited cirrus and therefore above normal sunlight intensity. Overall, sunlight intensity during June was above normal for most of the eastern half of the nation but below normal in the Southwest States. Fig. 8: June 2022 observed 300 MB (relative humidity) anomalies for the U.S. Please note: Verification of Climate Impact Company forecasts begin with the August report.