Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
562 FXUS65 KREV 240912 AFDREV Area Forecast Discussion National Weather Service Reno NV 212 AM PDT Tue Sep 24 2024 .SYNOPSIS... * A dry and mild pattern with weak RH recoveries on mid-slopes and ridgetops across western NV is expected this week. * Increased southwest winds are in the forecast on Wednesday and Saturday ahead of a couple of dry frontal passages during this week. * Cool nights with afternoon highs generally ranging 4-8 degrees above seasonal averages are expected going into the start of the weekend. && .DISCUSSION... The latest upper air RAP analysis for this morning shows an upper air ridge over the western CONUS with an upper air low residing off the coast of southern CA. Current satellite imagery and surface observations report dry conditions and light winds across the region underneath mostly clear skies this morning. Going through the remainder of today, forecast guidance shows the upper air ridge progressing eastward which will allow the aforementioned low to open up into a trough as it merges back into the jet stream by the evening hours. As a result of this upper air setup, dry conditions look to persist across the region with generally light winds in the forecast underneath mostly sunny skies. Daytime high temperatures for today look to range between the lower and upper 80s in the valley areas while Sierra Mountain communities in higher elevations have highs ranging between the lower 60s and the upper 70s. Tonight`s low temperatures look to range between the upper 40s and the upper 50s in the valley areas while the Sierra Mountain communities expect to be in the upper 30s to middle 40s range. For tomorrow, models are showing the CWA`s upper air flow taking a southwesterly direction in the Wednesday afternoon and evening hours due to the position of the upper air trough. This will lead to a dry frontal passage across the CWA at the surface during the evening hours with some increased winds out of the southwest ahead of the front in the afternoon. The quickest winds look to be seen in wind prone areas as well as in northern areas along the OR border. The latest NBM probabilities show around a 70-80% of wind gusts of 30 mph or higher on Wednesday afternoon within Eastern Modoc, Northeastern Lassen, and Northern Washoe Counties. As minimum relative humidity values in these areas continue to be forecast in the middle to upper teens, elevated to localized critical fire weather conditions look to be possible during the afternoon hours in these areas. Will continue to monitor this in case the critical fire weather conditions look to be become more widespread in upcoming forecast packages. On Thursday, slightly cooler temperatures are expected within the region behind the cold front with lighter winds. These winds look to persist into Friday as well with daytime temperatures rebounding a bit by warming back up. On Saturday, forecast guidance shows another potential upper air trough moving towards the CWA which will cause yet another dry frontal passage at the surface during the day. While winds are expected to increase during the afternoon, the latest NBM guidance shows only around a 10% chance for afternoon wind gusts to reach 25 mph or greater in areas closer to the OR border which is lower than previous runs. Will continue to monitor this in case the probabilities creep back up and cause fire weather concerns to increase again. Going into the beginning of next week, dry conditions expect to continue across the CWA behind the front with lighter winds on both Sunday and Monday. Ensemble guidance does look to show some signal for enhanced winds once again in the area on next Tuesday with the arrival of another potential trough. While forecast confidence at this time is low this far out, will watch to see if this signal is in future forecast runs going forward. -078 && .AVIATION... VFR conditions are expected at all REV TAF sites throughout today underneath mostly clear skies. On Wednesday, southwesterly winds are forecast to pick up a bit with afternoon gusts up to around 20-25 kts that may yield areas of turbulence along and east of the Sierra as a dry frontal passage tracks through the region. Very low chances for precipitation are also currently in the forecast for the region through the remainder of this week. -078 && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$