Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
034 FXUS66 KEKA 071222 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 522 AM PDT Sun Jul 7 2024 .SYNOPSIS...Extreme heat risk is expected for much of the interior today through Monday. Hot weather will continue in the interior all next week. A shallow marine layer will slowly rebuild today through Monday and likely bring periods of fog to coastal areas. && .DISCUSSION...Extreme heat is expected to continue today through Monday in the interior. Record high temperatures were exceeded yesterday (Saturday) with the all-time record high temperature of 117F tied at Ukiah. See climate section below. A few other stations had temperatures over 110F such as Eel River Camp RAWS 116F, Big Bar RAWS 118F and Gasquet 113F. Also, multiple automated weather stations in southern Lake peaked over 110F. Though records are not forecast for today, it will remain very hot and execessive heat warnings and heat advisories remain in effect for the interior. Overnight, many upper elevations stations in Mendocino and Lake counties, generally from 2500-3500 feet, have been in the upper 80s to mid 90s with relative humidity around 10-17%. The heat risk is forecast to remain extreme to major on Monday, before easing some mid to late in the week. Temperatures will remain well above normal all next week with pockets of extreme to major heat risk in Trinty, Lake and portions of interior Mendocino Counties. Temperatures along the coastal peaked in the mid 70s on Saturday, though only a few miles inland it warmed well into the lower to mid 80s. A shallow marine layer has been forming south of the Cape Mendocino with slivers of stratus and fog off the Mendocino coast. Coastal areas will start cool down today and Monday, though it will probably remain above early July normals (lower to mid 60s). High pressure will build toward the coast early to mid next week resulting in a return of northerlies offshore and an increase in stratus and fog for coastal areas. National Blend of Models (NBM) indicates temperatures remaining well above normal all next week. The heat risk is forecast to wane and become moderate next weekend with interior high temperatures mostly in the upper 90s to 102F except for 80s to lower 90s for coastal valleys of Humbodlt and Del Norte. A trough or cut-off low may create flow pattern favorable for thunderstorms late in the week or next weekend. Right now the probabilities are quite low (no more than 3%) for thunderstorms and if they do occur would likely be dry. DB && .AVIATION...A sparsely concentrated area of marine stratus is forming off of the coast of our northern most coastal zones, from Del Norte to Cape Mendocino. A denser swath of marine stratus carries on from Cape Mendocino down towards the SF bay area. The probability of this becoming an effective obscuration in regards to flight categories is mediocre considering the 24 hour trend and HREF around 60% for less than a mile of visibility. VFR for the immediate TAF period at all area terminals with soundings showing a deeper low level moisture development, Monday and Tuesday evening at KCEC. KACV soundings show shallow moisture tonight and deepening moisture on Monday and Tuesday evening as well. This could develop IFR conditions with advected marine stratus and a low level inversion capping the layer. Late afternoon winds at KUKI and prevailing VFR conditions are expected today. /EYS && .MARINE...Sustained northerly winds will reach up to 20 kts with gusts up to 25 kts in the outer waters this morning. Conditions for small crafts could be hazardous as locally generated wind waves with square properties traverse the northern and southern outer zones, starting this afternoon. Gusts south of Cape Mendocino will reach up to 33 kts within the inner waters, near shore. Northerlies and their associated wind waves begin to ease in the northern outer waters by Monday afternoon, yet continue in the southern outer waters through Tuesday. /EYS && .PREVIOUS FIRE WEATHER...Prolonged and extreme heat and dryness have continued to enhance fire weather conditions all across the area. Low pressure setting up along the coast has locally enhanced terrain winds, mostly in Lake County and along the Trinity River Valley. Though gentle in absolute term (gusts below 20 mph) combined with extremely dry RH, at least brief critical fire weather conditions should be expected int he afternoon and evening. Such critical conditions have so far been observed this evening and should be expected again in Trinity County Sunday evening. Fire danger will ease slightly this week as temperature decreases and RH eeks back closer to 20% with increased marine influence. Still, RH temperature will remain solidly above average with dry conditions through the week. As mentioned in the main discussion above, model ensembles are consistently showing a pattern mid to late week that could generate isolated thunderstorms. A very dry profile generally has thunder chances below 10 percent, but any storms that do form will be dry. Uncertainty remains high, but given the recent fuel dryness, any lightning could be impactful. /JHW no more than 3%) for thunderstorms and if they do occur would likely be dry. DB && .CLIMATE... * A RECORD HIGH TEMPERATURE OF 76 DEGREES WAS SET AT EUREKA CA, SATURDAY, JULY 6. THE OLD RECORD WAS 73 DEGREES SET IN 1954. * A RECORD HIGH TEMPERATURE OF 117 DEGREES WAS SET AT UKIAH CA MUNICIPAL AIRPORT, SATURDAY, JULY 6. THE OLD RECORD OF 108 DEGREES WAS SET IN 1905. THIS TIED THE ALL-TIME RECORD HIGH AT UKIAH MUNICIPAL AIRPORT, SET ON SEPTEMBER 9, 2022. && && .EKA WATCHES/WARNINGS/ADVISORIES... CA... Heat Advisory until 8 PM PDT Monday for CAZ102-112. Heat Advisory until 11 PM PDT this evening for CAZ104-106. Excessive Heat Warning until 8 PM PDT Monday for CAZ105-107- 108-110-111-113>115. Red Flag Warning from 2 PM this afternoon to 11 PM PDT this evening for CAZ283. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 3 PM PDT Monday for PZZ470. Small Craft Advisory until noon PDT Tuesday for PZZ475. && $$ 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