• This week's San Luis Obispo Tribune's Weather Watch Column Why did the Central Coast’s drought classification change so quickly? https://www.sanluisobispo.com/news/weather-news/article252876608.html • You can catch live weather forecasts weekday mornings from 6-9 a.m. on KVEC 920 AM on First Look with Andy Morris. • For weather updates, charts and photos, along with power outage information and other events you can follow me at: https://twitter.com/pge_john ========== PG&E DCPP Weather Forecast for Friday 07/23/21 ========== SEA/SWELL: A 3- to 5-foot northwesterly (295-degree, deep-water) swell (with an 8- to 11-second period) is forecast along our coastline today through Monday, decreasing to 2 to 4 feet with the same period on Tuesday. This northwesterly swell is expected to further lower to 2- to 3-feet (with a 8- to 11-second period) on Wednesday and remain at this level through next Friday. Arriving from the Southern Hemisphere: A 1- to 2-foot Southern Hemisphere (185-degree, deep-water) swell (with a 15- to 17-second period) will arrive along our coastline on Sunday and remain at this level through Tuesday. ATMOSPHERIC CONDITIONS: A 1,000-foot marine layer with pockets of fog and mist covers the coastal valleys and all the beaches early this morning. The stratus clouds will clear from coastal valleys later this morning, but will be slow to clear from the shoreline this afternoon. In fact, many of the beaches will remain overcast throughout the day. Along the marine low clouds will be a few high-level clouds that will stream over the Central Coast from the southwest. Today's high temperatures will range from the high 50s to mid-60s at the coast. The coastal valleys (San Luis Obispo) will reach the high 70s, while high-90s are expected in the Inland valleys (Paso Robles/ Mid-State Fair). As the northwesterly winds decrease, the marine layer will deepen and temperatures will continue to cool on Saturday. A trough of low pressure will develop along the California coastline on Sunday through Friday for gentle to moderate (8 to 18 mph) southerly to northwesterly (onshore) winds, and marine low clouds with areas of fog and drizzle. Combined with the marine layer, a surge of monsoonal moisture will move through the Central Coast on Monday into Tuesday with increasing high-level clouds and a chance of a few light rain showers. Thunderstorms could develop in the eastern regions of the Central Coast on Monday and Tuesday. This cloud cover will produce cooler daytime temperatures, while keeping it warmer during the overnight. Note: A chance of rain showers and isolated thunderstorms is expected in Southern California and the Sierra Nevada. The long-range models show fair and dry conditions persisting into the following week, with no indications of precipitation along the Central Coast. WILDFIRE INDEX RATINGS: COASTAL: FIA 508 INLAND: FIA 497, 510, 575, 580, 582 and 590 The PG&E Fire Index Ratings will be at medium (R2) levels along the Coastline and high (R3) levels in the Coastal Valleys. The Inland Valleys and the Far Inland areas will be at very high (R4) levels today and Saturday. The PG&E Fire Index Ratings will be at medium (R2) levels along the Coastline and high (R3) levels in the Coastal Valleys. The Inland Valleys will be at very high (R4) levels, while the Far Inland areas will be at exceptionally high (R5) levels on Sunday. DIABLO CANYON METEOROLOGICAL TOWER TEMPERATURE DATA: Yesterday's Today's Tomorrow's Min Max Min Max Min Max 54.5° 57.7° 53.3° 58.0° 54.0° 59.0° PG&E Weather Office in San Francisco predicted temperatures for San Luis Obispo County Inland Temperatures, Paso Robles Actual Predicted Thu Fri Sat Sun Mon Tue Wed Thu Fri 55 95 54 99 54 95 54 88 56 86 59 93 58 96 57 95 56 94 Coastal Valleys Temperatures, San Luis Obispo Thu Fri Sat Sun Mon Tue Wed Thu Fri 54 79 55 79 55 78 55 75 57 75 58 79 58 79 57 80 57 80 WINDS: Fresh to strong (19 to 31 mph) afternoon northwesterly winds are forecast today, decreasing to moderate to fresh (13 to 24 mph) levels on Saturday. Gentle to moderate (8 to 18 mph) southerly to northwesterly (onshore) winds are forecast on Sunday through next Friday. DIABLO CANYON METEOROLOGICAL TOWER WIND DATA: Today's Maximum Winds: Max peak winds: NW 11.0 mph @ 3:30 a.m. Max sustained wind: NW 8.0 mph @ 3:30 a.m. Yesterday's Maximum Winds: Max peak winds: NW 31.0 mph @ 4:15 p.m. Max sustained wind: NW 25.0 mph @ 4:15 p.m. SEAWATER TEMPERATURES: Seawater temperatures will range between 53 and 56 degrees through Saturday, warming to 54 to 57 degrees on Sunday into Monday. Seawater temperatures will further increase on Tuesday through next Friday. OCEAN CURRENTS: A southerly (offshore) flowing current is forecast to flow southward through Saturday. A northerly (onshore) flowing current will develop on Sunday into next Friday. SEAWATER VISIBILITY: Seawater visibility was 32 feet (top to bottom) at the Diablo Canyon Marina. ========================================================================== 24-Hour Ocean Condition Outlook for Friday 07/23 to Saturday 07/24 SWELL: DIR. NW HT. 3-5 PER. 8-11 This morning Remaining at: DIR. NW HT. 3-5 PER. 8-11 This afternoon Remaining at: DIR. NW HT. 3-5 PER. 8-11 Tonight WINDS: DIR. NW SPEED 10-15 This morning Increasing to: DIR. NW SPEED 20-25 + 30 This afternoon Decreasing to: DIR. NW SPEED 5-10 Tonight ========================================================================== 48-Hour Ocean Condition Outlook for Saturday 07/24 to Sunday 07/25 SWELL: DIR. NW HT. 3-5 PER. 8-11 Saturday morning Remaining at: DIR. NW HT. 3-5 PER. 8-11 Saturday afternoon Remaining at: DIR. NW HT. 3-5 PER. 8-11 Saturday night WINDS: DIR. NW SPEED 5-10 Saturday morning Increasing to: DIR. NW SPEED 15-20 + 25 Saturday afternoon Decreasing to: DIR. NW SPEED 5-10 Saturday night ========================================================================== Extended Ocean Condition Outlook: Gentle to moderate (8 to 18 mph) southerly to northwesterly (onshore) winds are forecast on Sunday through next Friday. ========================================================================== The 24 - Hour Ocean Data from the Diablo Canyon Waverider Buoy: MONTH DAY TIME SIG.HEIGHT PERIOD SWELL DIRECTION SST 07 19 0600 4.3 9 282 56.8 07 20 1800 5.4 8 286 59.0 07 21 1600 5.8 8 286 60.6 07 22 0800 5.6 8 284 53.6 07 23 0500 3.7 8 291 60.6 DCPP Ocean Lab Waverider Buoy Energy Spectral Analysis: Mo. daytime sig.ht. sig.per. energy (cm.sq.) (cm) (sec) 22+ 20 17 15 13 11 9 7 -------------------------------------------------------------------------- 07 19 0600 132 9 1 7 16 32 50 218 339 243 07 20 1800 165 7 1 6 14 35 25 35 312 608 07 21 1600 177 7 0 1 12 48 22 32 415 665 07 22 0800 172 7 1 3 11 54 40 51 344 642 07 23 0500 112 7 1 2 6 41 30 40 217 214 Daily Swell Inspection Program for today: NAME DAY TIME HEIGHT PERIOD SST (PDT) (FEET) (SECONDS) (DEG. F) # 66 Ocean Station Papa 23 0500 6 9 50.2 # 06 SE Papa 23 0550 4 7 n/a # 05 West Washington State 23 0550 4 7 60.3 # 59 California No Recent Reports # 36 Grays Harbor 23 0500 2 6 56.8 # 44 Humboldt Bay Waverider 23 0508 6 7 53.6 # 94 Cape Mendocino 23 0510 8 7 49.8 # 29 Point Reyes Waverider 23 0500 10 9 51.4 # 42 San Francisco Sandbar 23 0530 5 9 58.8 # 15 Monterey Waverider Buoy 23 0530 6 8 56.3 # 57 Point Sur 23 0500 6 8 56.7 # 28 Cape San Martin 23 0500 7 9 57.6 # 76 DCPP Waverider 23 0500 4 8 60.6 # 22 Santa Lucia Escarpment 23 0100 8 9 59.7 # 11 Point Arguello 23 0500 5 8 59.5 # 63 Harvest Buoy 23 0500 6 9 55.9 # 19 San Nicolas Island 23 0530 7 9 63.3 # 20 Scripps 23 0500 2 9 72.1 # 10 Waimea Bay, Hawaii 23 0531 5 8 78.8 # 33 Pearl Harbor Entrance 23 0500 3 7 79.5 # 04 SE Hawaii 23 0500 8 9 78.3 Precipitation at the Diablo Canyon Ocean Lab Wednesday 1500 through Thursday 1500 0.00 inches Thursday 1500 through Friday 1500 0.00 inches Precipitation this rain season (July 1 - June 30): 0.00 inches Average season rainfall at DCPP to date: 0.00 inches Ocean Lab Barometer: 30.01 in/Hg or 1016.2 mb 0.0 mb (steady) Today's Sunrise 6:06 AM Sunset 8:13 PM Tomorrow's Sunrise 6:07 AM Sunset 8:12 PM Tides: Low Tide High Tide AM PM AM PM 23 Friday 4:36 -1.4 3:43 2.5 11:20 4.1 9:56 6.9 24 Saturday 5:20 -1.4 4:35 2.4 (12:03 4.2) 10:44 6.7 25 Sunday 6:03 -1.2 5:28 2.4 (12:44 4.3) 11:31 6.3 26 Monday 6:44 -0.8 6:23 2.4 ----- --- 1:26 4.4 27 Tuesday 7:24 -0.3 7:21 2.4 12:18 5.7 2:07 4.5 28 Wednesday 8:02 0.3 8:28 2.3 1:07 5.1 2:49 4.6 29 Thursday 8:40 0.9 9:43 2.2 2:02 4.4 3:31 4.7 ========================================================================= This day in weather history 1788 - A weather diary kept by George Washington recorded that the center of a hurricane passed directly over his Mount Vernon home. The hurricane crossed eastern North Carolina and Virginia before moving into the Central Appalachians. Norfolk, VA, reported houses destroyed, trees uprooted, and crops leveled to the ground. (David Ludlum) 1898 - A two hour thunderstorm deluged Atlanta, GA, with 4.32 inches of rain. More than a foot of water flooded Union Depot. Many street car motors burned out while trying to run through flooded streets. It grew so dark before the afternoon storm that gas lights were needed. 2017 - The Eastern Pacific region remains active with three tropical cyclones: Greg, Irwin and Hilary. Tropical Storm Hilary is forecast to become a major hurricane off the coast of Baja California and move in a northwesterly direction. Southeasterly (260-degree, deep-water) swell from this cyclone will arrive along the Southern California coastline on Friday and peak on Sunday at 7- to 9-feet (with a 14- to 16-second period) with sets of waves reaching well over 14 feet. 2018 - Away from the coastline, temperatures will warm to triple- digit levels in the North County today into Friday. In fact, by Wednesday and Thursday, they may break daily high records, reaching 110 degrees on both days. ======================================================================== This weather forecast is a service provided by Pacific Gas and Electric Company (PG&E) to our energy customers. The forecast is valid only for the Diablo Canyon Power Plant coastline area (approximately a one-half mile radius surrounding the plant). Some of the information in this forecast is provided by Pacific Weather Analysis, with their permission. Replication of this email must be in its entirety. You may view and copy material from this forecast, provided you retain all copyright, trademark, and other proprietary notices displayed on the materials. Use of these materials in publications, radio, television, other media presentations, or other websites is prohibited without PG&E's express written consent. PG&E is a subsidiary of PG&E Corporation, one of the largest natural gas and electric utilities in the United States, delivering some of the nation's cleanest energy to 15 million people in Northern and Central California. If you would like to subscribe or unsubscribe to this daily forecast, please send an email to PGEweather@pge.com. Any questions about this forecast, please E-mail John Lindsey at jcl5@pge.com