Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
916 FXUS66 KEKA 202157 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 257 PM PDT Sat Jul 20 2024 .SYNOPSIS...Temperatures will be slightly cooler Sunday as a weak trough moves by the area. There is a slight chance for thunderstorms this evening, mainly in northern Trinity and northeastern Del Norte counties. A drying and warming trend develops early next week with temperatures peaking Tuesday and starting to cool off later in the week. && .DISCUSSION...The high pressure is just off to the east of the area and shortwave is moving up off the coast of CA. This is bringing a little bit of moisture aloft up into the area this afternoon. A few clouds are forming over the higher terrain of southern Trinity county. This is expected to continue to move north this afternoon and evening. There is still the potential for a thunderstorm or two late this evening in northern Trinity county and northeastern Del Norte county. Sunday the threat for thunderstorms is expected to remain off to the east of the area. Temperatures will be 3 to 5 degrees cooler than today and this is expected to be the coolest day. Models are showing clouds lingering through the day at the coast, however confidence is low on this. Cooler temperatures aloft should weaken the inversion and northwest winds are also expected to increase along the coast, these may help increase clearing more than expected on Sunday. Monday and Tuesday warming aloft is expected to bring hot temperatures to the inland areas. This is expected to shrink the marine layer which may bring fog to the coastal areas. Highs inland are expected to be over 100 in most of the warmer inland valleys. The valleys are expected to see lows drop to around 60 providing some relief overnight, however the ridges are expected to remain over 70 on the higher terrain. The highest Heat Risk is expected to be in southern Lake county on the higher terrain so have issued a heat advisory for southern Lake county. This may need to be expected into northern Lake or Mendocino counties as confidence grows. Mid to late in the week the ridge is expected to start breaking down as the trough starts to move into the Pacific Northwest on Wednesday. Initially there is some uncertainty on how quickly this trough moves in from the west. The coastal counties will likely see some cooling Wednesday, but areas farther inland will likely see another warm day. One of the clusters shows some instability making Wednesday a possible day to see some convection, but it may be too dry for convection. This may also deepen the marine layer as the trough moves onshore. Thursday cooler temperatures are expected across the area. This trough brings mainly southwest flow aloft and the ensemble clusters are in good agreement on the airmass being too dry for thunderstorms. Continued cooling is expected on Friday as the trough moves onshore. MKK && .AVIATION...MVFR/IFR ceilings have been reported early this afternoon at the coastal terminals. Satellite is showing very little clearing early this afternoon. Some clearing is possible late afternoon, but would be shortlived as clouds rebuild this evening. Gusty northerly winds are forecast this afternoon in CEC and UKI and will die down after sunset. VFR conditions are expected to prevail at UKI today. JB && .MARINE...Northerly winds will continue to gradually increase as a pressure gradient tightens in the coming days. The largest winds will continue to be seen in the lee of Cape Mendocino, with localized gusts of 35-40 kts forecast this afternoon, with winds of 25-30 kts elsewhere in the southern waters. The northern waters have slightly lower winds with peak gusts this afternoon around 20-25 kts. Sunday, winds increase with gale force gusts in much of the southern waters and localized gales around Pt St. George. By Monday, widespread gales force gusts of 40-45 kts are forecast in the outer waters. Steep seas this weekend of 7-8 ft will increase to 10-14 ft Monday and Tuesday. Some improvement is expected midweek. JB && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory from 3 PM Sunday to 9 AM PDT Monday for PZZ450. Small Craft Advisory until 9 PM PDT Sunday for PZZ455-470- 475. Gale Watch from Sunday evening through Tuesday afternoon for PZZ470-475. && $$ 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