Department of Meteorology Naval Postgraduate School Monterey, 93943

SUMMARY of the March 2021 WEATHER ON THE MONTEREY PENINSULA General: March 2021 goes into the books with below normal temperatures and rainfall, seasonable winds and minimal fog. During most of March, the local area was on the cold side of a stubborn upper- level ridge that stayed to just to our west. Several storm systems made it over the top of this ridge providing plenty of cool air, but not very productive in the rainfall department. Temperature: March was somewhat remarkable, temperature-wise, with maximum and minimum temperatures quite cool and in a tight range until 24 March (see graphic of daily temperatures and rainfall from Upper Monterey, below). The last week of March saw some warmth with three weak offshore flow events giving highs in the upper 60s°F to low 80s°F separated by cold temperatures. Unusual for the Monterey area was a 40°F temperature range at our Salinas station on 31 March with a low of 46°F and a high of 86°F. Marina recorded a 39°F temperature range on this day with a 44°F low and 83°F high. For the month, Upper Monterey registered an average high of 59.7°F, 2.3°F below normal and an average low of 45.1°F, exactly normal. Highest temperature reading at our Upper Monterey site was 82°F on 31 March and lowest was 41°F on three days during the month. Daily records for Upper Monterey included: 53°F cool maximum on 21 March (previous record was 54°F in 1987), 82°F warm maximum on 31 March (was 80°F on this date in 2000), and 60°F warm minimum on 31 March (was 54°F in 2011). In the local area, highest readings were 86°F at Salinas and 84°F at NPS, and Carmel Valley. The cool spots were Marina and Carmel Valley, both recording 33°F during the month. Marina reported seven days with frost (normal is three), with the last on 30 March – making it the frostiest of March since 1987. Normal last day of frost for Marina is 24 March, and 17 March for Upper Monterey. (See Table of Comparative Weather Data for Stations contributing to this summary, and graphic of daily temperatures and rainfall from Upper Monterey, below). Precipitation: Much like February, below normal precipitation was recorded during March at Upper Monterey, where 1.51” was measured falling on seven days. Normal for March is 3.10” falling on nine days. Rain-year totals now range from 45 to 61% of normal for local stations. Wind: Highest winds recorded in the local area were 35 mph at Fort Ord on 15 March and 32 mph at Monterey on 03 March. Average winds for March were 6.6 mph at the Airport, and 9.6 mph at Fort Ord, both close to seasonal average. Fog: Before April 2018, with 45 years of record, a fog-day was at least one hour of visibility less than six miles. Since then, a fog-day is one or more hours with visibility less than or equal to 1/4 mile. “Mist Days” are when visibility between 1/4 and six miles is reported for at least one hour. Long term statistics for fog describe “mist” days. Mist and fog-days at Monterey Peninsula Airport and Marina fog- days for the last three months: Monterey Peninsula Airport Marina Mist Days (Normal) Fog Days Fog Days (Normal) (vis. <6 mi) (vis. <1/4 mi) (vis. <1/4 mi) January 2021 8 (6) 2 3 (2) February 2021 6 (6) 2 3 (2) March 2021 2 (7) 0 0 (3)

OUTLOOK for average temperature and precipitation for Monterey, April through June 2021: NOAA’s Climate Prediction Center ENSO (El Niño / Southern Oscillation) discussion summary on 05 April 2021 reports “La Niña conditions are present. Equatorial sea surface temperatures (SSTs) are below average from the west-central to eastern Pacific Ocean. The tropical atmospheric circulation is consistent with La Niña. There is a ~60% chance of a transition from La Niña to ENSO-Neutral during the Northern Hemisphere spring 2021 (April-June). Links to some NOAA climate pages: https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf https://www.cpc.ncep.noaa.gov/products/predictions/multi_season/13_seasonal_outlooks/color/churchill.php Seasonal outlooks from NOAA’s Climate Prediction Center for April through June 2021 indicate above normal temperatures for the coast and close to equal chance of normal rainfall. Normal temperatures and rainfall for Monterey for the next three months: Month Rainfall (inches) # of rain days Normal Max/Min. Temps (°F) April 1.51 6 63.3 / 45.9 May 0.49 4 64.5 / 48.1 June 0.20 3 66.3 / 50.6

NOTE: Current and past Monthly Monterey Peninsula Weather Summaries, as well as historic and climate information from the National Weather Service Climate Station, are available electronically at the following website: https://met.nps.edu/~ldm/renard_wx/

Comparative Weather Data for Stations on/near the Monterey Peninsula & Salinas March 2021

Following are comparative figures from eleven local observation sites: 1) Upper Monterey, located in the western hilly section of Monterey (elevation 606 ft); 2) Monterey Peninsula Regional Airport (KMRY) site (elevation 257’), located in the flat area of eastern Monterey; 3) Naval Postgraduate School Campus (NPS), Monterey, (elevation 45’); 4) the Ft. Ord site (Ft. Ord) elevation 167’, located just north of the Marina Municipal Airport. This is the site of the Naval Postgraduate School’s wind profiler managed by the Department of Meteorology); 5) Marina, located about 2½ miles ESE of Monterey Bay (elevation 135’); 6) Carmel Valley village vicinity Ford Rd. and Lilac Ln. (elevation 475’); 7) Salinas, vicinity of W. Blanco Rd. within ½ mile of S. Main St.; 8) Carmel, located on Rio Road near east end; 9) Seaside, vicinity of Paralta and Military Aves.; 10) Pacific Grove, vicinity of Sunset and Congress Sts.; 11) Big Sur Ranger Station, Highway 1, Big Sur.

Temperatures (°F) Precipitation (inches) Wind (mph) Location Rain-year Normal / Avg. Highest Avg. Lowest This month (01 Jul – % of normal Max. Gust / Average Max. Min. March 31 Mar date(s) Upper 17.30* / ( 21 ) Monterey 59.7 82 45.1 41 1.51 b 10.77 61% 23rd 1.7 Monterey % ( 32 ) Airport 61.9 75 45.1 40 1.47 b 7.56 --- 3rd 6.6 NPS 13.88# / ( 30 ) 62.2 84 42.5 36 1.68 d 7.91 57% 3rd 3.2 Ft. Ord ( 35 ) 59.8 84 39.5 35 1.25 b 8.26 --- 15th 9.6 Marina 13.82 & / ( 31 ) 60.9 83 40.3 33 1.37 a 7.98 58% 14th,15th --- Carmel Valley 64.7 84 39.2 33 1.62 10.65 ------Salinas 12.61 ∆ / 63.9 86 43.3 37 0.96 5.71 45% ------Carmel 58.8 77 43.9 39 1.77 8.83 ------Seaside 59.5 81 41.8 36 1.31 6.67 ------Pacific Grove 59.6 81 44.6 40 1.55 9.01 ------Big Sur 62.2 80 40.8 36 3.09 17.50 ------

FOOTNOTES: Observations for precipitation: a = 5 or 6 PM, b = midnight PST, c = 3 or 4 PM, d = 6 to 8 AM * = NWSCS/Upper Monterey 66-year average # = 51-year average, & = 37-year average, ∆= 24-year average % = Monterey Peninsula Regional Airport replaced NWSFO on 01 April 2019; Winds from Monterey Peninsula Airport (based on a 24-h period, ending at local midnight)