Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
601 FXUS66 KEKA 021240 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 540 AM PDT Sun Jun 2 2024 .SYNOPSIS...A very late season atmospheric river will bring light rain to the North Coast this afternoon, with a period of moderate to heavy rainfall late tonight into Monday. Heat will quickly build back in by mid next week with interior highs over 100 degrees. && .DISCUSSION...A warm front approaches northern California from the northwest this morning, followed by a cold front coupled with a west- southwest moisture flux tonight into Monday morning. Latest TPW- Sat layer blended total precipitation water shows 1 inch along the coast. The precipitable water content is expected to increase up to 1.5 inch by mid-late morning. Light rain will begin to push into Del Norte County and northern Humboldt this afternoon, and then spread southward all along the coast. The potential for heavier rain rates will arrive late tonight into Monday morning as the west-southwesterly IVT plume intersects the coastal terrain, mainly in Del Norte County and northern Humboldt where 1.5 to 2 inches of rain is expected in 24 hour, with locally higher amounts. HREF probabilities indicates around 70-100% for 1 inch or more in 6 hours from midnight to 6AM PDT. Max rain rates for both areas looks around 0.3 in/hr to 0.4 in/hr, with some localized up to 0.5 in/hr over the higher terrain in Del Norte County. The Weather Prediction Center (WPC)included Del Norte County in the Marginal Risk (at least 5%) of excessive rainfall for Sunday and Monday. Even around Humboldt Bay, 0.2 to 0.5 inches is most likely. More minor wetting rain of 0.1 to 0.2 inches is most likely in Trinity and along the Mendocino coast through early Monday afternoon with only trace amounts for the more southern interior. Impacts will generally be minor with debris on roadways and slipperiness from oil buildup will be the main concerns. The cold front will quickly eject eastward away from the west coast Monday morning, with lingering post-frontal showers gradually tapper off Monday afternoon. Temperatures will be cooler across the interior with highs in the 70`s. High pressure over eastern Pacific will build quickly over the West Coast in the wake of the this front. The mid level heights will rise slightly, and a warmer airmass will gradually develop across the WRN CONUS during the remainder of the week. Interior highs temperatures are forecast to peak on Wednesday and Thursday, with values across the hottest valleys ranging from 95-105 degrees. The heat risk is forecast to be minor to moderate over the area, but a major heat risk is expected to occur over portions of Lake County. Thus, this will affect anyone without effective cooling and/or adequate hydration. Velez && .AVIATION...Satellite imagery in the water vapor spectrum is highlighting Integrated Water Vapor plumes headed towards the PNW coast. Cloud cover is increasing this morning with ceilings lowering as the moisture heads towards our CWA. Oregon coast will be exposed broadside to the focused plume with indirect trailings working their way south to KCEC and the rest of the CWA. KCEC should see rain by noon, keeping flight conditions IFR with lowered visibility and sub 1000ft ceilings. Similar conditions at KACV with IFR conditions through the afternoon. Gusty north winds will return to KUKI by the afternoon, which has been the trend for the past few days. Light precipitation is possible tonight at KUKI. /EYS && .MARINE...Seas will drop range from 3 to 5 feet with the arrival of a small, period NW swell at around 3-4 ft at 10 seconds. Winds will be light, up to 12 kts and split in flow. Southerly winds will increase tonight through Monday morning ahead of a trough. On Monday, a slightly larger, mid period NW swell will move in, building to around 8 ft at 10 seconds early Tuesday morning. Light, split wind flow will transition to light northerly winds Monday. These winds will slowly increase in the southerly zones, initially south of the cape. Tuesday, the NW swell will hold in size, then slowly lowering late in the day. A larger reinforcing swell then move in. Northerly winds in the southern waters will further increase, exceeding 22 kts south of the cape in the afternoon. On Wednesday, a seasonably large, longer period WNW swell (300 degrees) will build in, currently forecast up to around 12 ft at 14 seconds. Northerly winds will be on the increase throughout the day, with gale conditions probable by late Wednesday. /JJW /EYS && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Excessive Heat Watch from Tuesday morning through Thursday evening for CAZ114-115. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png