Area Forecast Discussion
Issued by NWS Eureka, CA
Issued by NWS Eureka, CA
587 FXUS66 KEKA 232149 AFDEKA AREA FORECAST DISCUSSION National Weather Service Eureka CA 249 PM PDT Mon Sep 23 2024 .SYNOPSIS...One more day of hot weather is forecast in the interior on Tuesday. Cooling is expected on Wednesday, followed a warming trend Thursday and Friday. Coastal stratus with patchy fog will likely return around mid week. && .DISCUSSION...Deep column of warm air aloft coupled with offshore wind flow has been resulting in warmer temperature along the coast and in the interior of NW California today. Temperatures have been running 5 to 15F warmer compared to yesterday at this time. Temperatures are projected to peak around 95-104F in the interior valleys. Anomalous warmth has also been occurring over coastal areas and adjacent river valleys. Crescent City airport has reach 72F while Fortuna airport warmed up to 77F. Hot weather with highs 5 to 15F above normal is forecast to continue in the interior on Tuesday. Weakening offshore flow and afternoon sea breezes will probably result cooling for much of the coast on Tue, although temperatures may rapidly warm up into the lower to mid 70s in the morning before a shallow layer of cool-damp marine air returns. Heat risk in the interior is forecast to remain moderate through Tuesday except within the thermal belt where overnight lows in the 70`s are expected. This level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. High pressure aloft will begin shift eastward Tuesday night as an upper level trough approaches the Pacific Northwest. Meanwhile, a dry cutoff low located offshore southern California will drift northward parallel to the coast before being absorbed by the upstream trough by early Wednesday. Marine layer will likely develop during this time frame. Daytime high temperatures will diminish to near or below seasonal averages in the interior. Seasonal averages range from 82-88F in the interior. Chances for precipitation with this incoming trough is quite meager, generally 10% or less. If anything, some light drizzle may occur in coastal areas with no impacts. Ensemble means and deterministic guidance indicates above normal 500mb heights and above normal 850mb temperatures Thu-Sun. This will most likely result in above normal interior high temperatures. How much above normal is not 100% certain. Looking at the National Blend of models (NBM), sure enough chance for 90-95F increases as early as Friday. Dry weather and above normal interior high temps are most probable Fri-Mon. DB && .AVIATION...Benign "flying" weather conditions generally prevailed across the region today. However, there were a few brief early morning pockets of LIFR/IFR stratus and fog...mainly near CEC. Cirrus clouds streamed across the region, otherwise skies were SKC. The pressure gradient along the Del Norte Coast promoted breezy to some gusty diurnal winds. Also, marginal above ground winds over Del Norte were the catalyst for LLWS until noonday. Overnight/Thursday morning: a consensus of a couple of model data indicates that the marine layer will redevelop at the coast and cause low Cig/Vis at ACV and CEC terminals. However, model data is also indicating pronounced offshore flow overnight which would promote a lack of clouds (for the most part); Bufkit agrees with that scenario. On the 18z Tafs though, some low cloud and visibility obstructions. /TA && .MARINE...Northerly winds and steep waves will continue to diminish tonight through Tuesday. A series of mid period NW swell groups will build through mid week and peak around 8 ft on Wed. Potential for gale force northerlies and large steep waves over 10 feet will increase Fri-Sat. DB && .FIRE WEATHER...Elevated conditions with low daytime RH`s and locally gusty winds are forecast to continue through Tuesday. Temperatures will remain hot on Tuesday with daytime RH`s from 10-20%. Offshore flow will continue on Tue, however ridge level winds will become southeasterly by early Tue morning, and then turn westerly to southwesterly in the afternoon. A trough will move across the area on Wed and daytime temperatures will cool down. RH`s should also increase on Wed-Thu, but minimum RH`s will still be low, around 20-30% in the interior. Warmer and drier conditions with stronger N-NE winds expected Fri-Sat. Elevated to locally critical conditions will be possible. DB && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... Small Craft Advisory until 8 AM PDT Tuesday for PZZ470. Small Craft Advisory until 9 PM PDT this evening 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