• This week's San Luis Obispo Tribune's Weather Watch Column "‘The oceans are taking a beating’: Seawater temperatures on SLO’s coast keep getting higher" www.sanluisobispo.com/news/weather/weather-watch/article231607708.html • You can catch the live weather forecasts weekday mornings from 6-9 on the 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 Wednesday 06/19/19 =========== SEA/SWELL: Today's 3- to 5-foot northwesterly (300-degree, deep- water) swell (with an 8- to 12-second period) will remain at this level through Thursday morning, increasing to 6 to 8 feet (with an 8- to 11-second period) on Thursday afternoon and will remain at this height through Saturday morning. This northwesterly (300-degree, deep-water) swell will lower to 4- to 6-feet (with an 8- to 11-second period) on Saturday afternoon into Monday morning. Increasing northwesterly winds Monday afternoon through Wednesday will generate a 6- to 8-foot northwesterly (320-degree, deep-water) sea and swell (with a 5- to 11-second period) over the time frame. Arriving from the Southern Hemisphere: This morning's 2- to 4-foot Southern Hemisphere (220-degree, deep-water) swell (with a 15- to 17- second period) will remain at this level through tonight. A 1- to 3-foot Southern Hemisphere (200-degree, deep- water) swell (with a 16- to 18-second period) will arrive on Thursday into Saturday. ATMOSPHERIC CONDITION: Gentle to moderate (8 to 18 mph) southerly to northwesterly (onshore) winds today through Thursday will continue to produce persistent marine low clouds with areas of fog and mist/drizzle in the coastal regions. The marine layer will clear by the afternoon in the coastal valleys, but will remain overcast along the beaches throughout the day. Today's high temperatures will reach the low to mid- 80s in the North County (Paso Robles), while the coastal valleys (San Luis Obispo) will range between the low to mid-70s. The beaches will warm to the low-60s. An upper-level low-pressure system is expected to move through the Central Coast on Thursday into Friday with slightly stronger northwesterly (onshore) winds and night and morning drizzle along the coastline. In fact, the drizzle may be heavy enough to be measurable (one or two hundreds of an inch) in many of our beach communities. This system will also produce cooler weather with Paso Robles only reaching the mid to high-70s and San Luis Obispo the low-70s. High-pressure will build over the Central Coast on Saturday into Sunday for warmer inland and coastal valley temperatures, but the marine layer will continue to persist in the coastal regions. A change in the weather pattern will occur on Monday into next Wednesday as fresh to strong (19 to 31 mph) northwesterly winds develop along the coastline. These winds should be strong enough to mix out the marine layer, leaving behind sunny skies along many of the beaches. Overall, temperatures should remain seasonably cool with no clear signs of any heat waves through the end of June or longer. WILDFIRE INDEX RATINGS: Today's PG&E Fire Index Ratings are at medium levels along the coastline and coastal valleys, while the inland valleys are at high levels. The PG&E Fire Index Ratings will lower to low levels along the coastline and coastal valleys and medium levels in the inland valleys on Thursday. Weather graphics and power outage information are available at: twitter.com/pge_john. Yesterday's Today's Tomorrow's Min Max Min Max Min Max 55.5° 61.1° 55.3° 60.0° 55.0° 60.0° PG&E Weather Office in San Francisco predicted temperatures for San Luis Obispo County Inland Temperatures, Paso Robles Actual Predicted Tue Wed Thu Fri Sat Sun Mon Tue Wed 51 92 54 85 58 76 50 79 51 84 51 84 49 78 48 75 47 77 Coastal Valleys Temperatures, San Luis Obispo Tue Wed Thu Fri Sat Sun Mon Tue Wed 53 72 57 72 58 72 54 70 54 71 52 72 52 66 52 67 53 70 WINDS: Gentle to moderate (8 to 18 mph) southerly to northwesterly (onshore) winds are forecast later today through Thursday. Moderate to fresh (13 to 24 mph) afternoon northwesterly winds are forecast on Friday and Saturday, decreasing on Sunday. Fresh to strong (19 to 31 mph) northwesterly winds are expected on Monday into next Wednesday. DIABLO CANYON METEOROLOGICAL TOWER WIND DATA: Last night's Maximum Winds: Max peak winds: SE 10.0 mph @ 4:45 a.m. Max sustained wind: SE 8.0 mph @ 4:45 a.m. Yesterday's Maximum Winds: Max peak winds: NW 14.0 mph @ 11:45 a.m. Max sustained wind: NW 9.0 mph @ 11:45 a.m. SEAWATER TEMPERATURES: Intake seawater temperatures will range between 54 and 57 degrees though today, increasing to 56 to 59 degrees on Thursday into Sunday. OCEAN CURRENTS: A southerly (offshore) flowing current will develop during the afternoon, shifting to the north (onshore) during the night and morning. This pattern will continue into Sunday. SEAWATER VISIBILITY: Seawater visibility was 8 to 10 feet at the Diablo Canyon Marina. ========================================================================== 24-Hour Ocean Condition Outlook for Wednesday 06/19 to Thursday 06/20 SWELL: DIR. NW HT. 3-5 PER. 8-12 This morning Remaining at: DIR. NW HT. 3-5 PER. 8-12 This afternoon Remaining at: DIR. NW HT. 3-5 PER. 8-12 Tonight (Combined with: DIR. SW HT. 2-4 PER. 15-17 All day) WINDS: DIR. VAR. SPEED 5-10 This morning Increasing to: DIR. NW SPEED 10-15 This afternoon Decreasing to: DIR. VAR. SPEED 5-10 Tonight ========================================================================== 48-Hour Ocean Condition Outlook for Thursday 06/20 to Friday 06/21 SWELL: DIR. NW HT. 3-5 PER. 8-12 Thursday morning Remaining at: DIR. NW HT. 3-5 PER. 8-12 Thursday afternoon Remaining at: DIR. NW HT. 3-5 PER. 8-12 Thursday night (Combined with: DIR. SW HT. 1-3 PER. 16-18 All day Thursday) WINDS: DIR. SE SPEED 5-10 Thursday morning Increasing to: DIR. NW SPEED 10-15 Thursday afternoon Decreasing to: DIR. VAR. SPEED 5-10 Thursday night ========================================================================== Extended Ocean Condition Outlook: Increasing northwesterly winds Monday afternoon through Wednesday will generate a 6- to 8-foot northwesterly (320-degree, deep-water) sea and swell (with a 5- to 11-second period) over this time frame. ========================================================================== The 24 - Hour Ocean Data from the Diablo Canyon Waverider Buoy: MONTH DAY TIME SIG.HEIGHT PERIOD SWELL DIRECTION SST 06 14 0733 2.4 13 226 54.3 06 15 2133 4.5 9 293 54.0 06 16 2203 4.0 20 220 53.6 06 17 2133 6.1 11 286 54.5 06 18 0633 4.4 17 209 58.6 06 19 0203 4.2 17 215 55.8 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 -------------------------------------------------------------------------- 06 14 0733 73 3 2 3 14 37 61 55 23 120 06 15 2033 131 4 5 17 13 12 21 35 272 428 06 16 2203 122 9 2 96 76 56 83 55 202 185 06 17 2133 192 11 2 28 64 64 128 883 768 156 06 18 0633 136 9 3 30 144 76 66 251 277 173 06 19 0203 131 11 2 8 107 111 68 302 248 109 Daily Swell Inspection Program for today: NAME DAY TIME HEIGHT PERIOD SST (PST) (FEET) (SECONDS) (DEG. F) # 66 Ocean Station Papa 19 0203 7 8 50.2 # 05 West Washington State 19 0250 5 8 n/a # 02 West Oregon The buoy went adrift 02/09/19 # 06 SE Papa 19 0250 4 15 63.9 # 59 California 19 0250 11 9 58.6 # 44 Humboldt Bay Waverider 19 0200 12 9 50.2 # 29 Point Reyes Waverider 19 0233 11 11 54.5 # 42 San Francisco Sandbar 19 0200 5 12 56.5 # 15 Monterey Waverider Buoy 19 0203 8 11 56.7 # 28 Cape San Martin The buoy went adrift 04/04/19 # 76 DCPP Waverider 19 0203 4 17 55.8 # 22 Santa Lucia Escarpment 19 0203 5 10 58.3 # 11 Point Arguello 19 0250 6 11 57.7 # 63 Harvest Buoy Not reporting this morning. # 19 San Nicolas Island 19 0233 5 13 60.3 # 20 Scripps 19 0202 2 17 66.6 # 33 Pearl Harbor Entrance 19 0200 3 6 81.0 # 04 SE Hawaii 19 0250 8 9 79.2 Precipitation at the Diablo Canyon Ocean Lab: Monday 1500 through Tuesday 1500 0.00 inches Tuesday 1500 through Wednesday 1500 0.00 inches Precipitation this rain season (July 1 - June 30): 20.08 inches Average season rainfall at DCPP to date: 19.00 inches Ocean Lab Barometer: 29.97 in/Hg or 1014.9 mb -0.4 mb (Falling) Today's Sunrise 5:49 AM Sunset 8:21 PM Tomorrow's Sunrise 5:49 AM Sunset 8:21 PM Tides: Low Tide High Tide AM PM AM PM 19 Wednesday 6:36 -0.8 5:43 2.8 (1:35 3.8) 11:43 5.5 20 Thursday 7:16 -0.6 6:31 2.9 ---- --- 2:23 3.8 21 Friday 7:57 -0.3 7:27 3.0 12:22 5.1 3:12 3.8 22 Saturday 8:39 0.0 8:36 3.0 1:04 4.7 4:01 3.9 23 Sunday 9:22 0.3 9:59 2.9 1:53 4.3 4:45 4.0 24 Monday 10:05 0.7 11:21 2.5 2:54 3.8 5:24 4.3 25 Tuesday 10:48 1.0 ----- --- 4:10 3.5 5:58 4.5 26 Wednesday 11:30 1.4 (12:29 2.1) 5:35 3.2 6:30 4.8 27 Thursday 1:22 1.5 12:12 1.7 6:56 3.2 7:01 5.2 ======================================================================== This day in weather history 2008 - A very unusual weather pattern developed in San Luis Obispo County, as a mesoscale high pressure (1018 mb) system over the California valley produced three days of record breaking heat. The air mass coming off the Cuesta Grade was very dry with humidity levels below 10 percent. By June 20, the temperatures reached 111 degrees at the San Luis Obispo County Airport, 110 degrees in Los Osos and 115 degrees at the Diablo Canyon front gate at Avila Beach. 2015 - Once again, just like the day before, a strong temperature gradient developed between the coastline and North County yesterday. The high temperature hit 101 degrees at the Paso Robles Municipal Airport, while Diablo Canyon Power Plant only reached 54 degrees. The main story this morning is the Santa Lucia (northeasterly) winds. The PG&E Black Butte weather station on the Cuesta Grade reported sustained northeasterly winds of 24 mph with gust to 40 mph at 6 a.m. These winds prevented coastal low clouds from developing along the shoreline and will produce warmer temperatures in the coastal valleys and along the beaches this morning. ======================================================================== 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