Area Forecast Discussion
Issued by NWS Reno, NV
Issued by NWS Reno, NV
965 FXUS65 KREV 160949 AFDREV Area Forecast Discussion National Weather Service Reno NV 249 AM PDT Mon Sep 16 2024 .SYNOPSIS... * Well-below average temperatures are expected today, in addition to widespread rain showers and high elevation snow. * Another cold storm brings continued below average temperatures and additional precipitation chances Tuesday into Wednesday. * A warming and drying trend follows for the remainder of the week. && .DISCUSSION... Current radar imagery depicts a band of stratiform precipitation extending in a north-south orientation over Mineral, Churchill, and Pershing counties early this morning. This band is attributed to increased moisture transport around the eastern periphery of an upper-level low moving inland into northern California this morning. This low will slowly track east through the morning hours, with widespread showers gradually wrapping around the low through the remainder of the day. Latest high-resolution guidance shows this band taking residence over the Basin & Range through a majority of this morning, wrapping northwest into areas north of I-80 by the early afternoon, then dropping south along the Sierra and western Nevada through the evening. Given the residence time of the band over the Basin & Range, heaviest precipitation accumulation is expected in this area, with a 20-30% chance to see over an inch of liquid through Tuesday morning for areas east of US-95. Wetting rains (>0.10") are a good bet for western Nevada and northeastern California with a 80-90% chance. Due to the mainly southeasterly flow associated with this system, chances for wetting rains drop off significantly for Sierra valleys, with recent guidance only indicating a 20-30% chance. Some isolated thunderstorms are possible through this evening, with a 15-20% chance mainly north of I-80 and east of US-95. This system has brought a much cooler airmass to the region, with snow levels dropping to around 7500 ft this morning, then increasing to 8000-8500 ft through the remainder of the day. With showers not expected to impact the Sierra until the warmer parts of the day, any snow accumulations will mainly be confined to the Sierra above 8000 ft. Brief lowering of snow levels is possible under heavier showers, so some flakes mixing down to pass level is not out of the question. Regardless, travel will be slick across the entire region given this is the first rain we have seen in quite some time. Leave extra time and space for your commutes today. The upper-low swiftly exits the region on Tuesday, though some showers may linger over the Basin & Range through Tuesday morning. Another storm follows quickly on its heels, though digs a bit farther west and south Tuesday into Wednesday. This system will bring widespread precipitation chances once again, with early high-resolution guidance showing showers spreading into the Sierra early Wednesday morning, then sliding southeast. This system will be a bit warmer, with snow levels around 9000-9500 ft. As such, expect precipitation to fall mainly as rain, with the exception of the high Sierra in Mono County. Temperatures will be quite brisk through Thursday under the influence of these two systems, with high temperatures struggling to break the 70 degree mark even for warmest western NV valleys. The coldest day will be Wednesday as skies clear behind the secondary system, with temperatures 20-25 degrees below average. Ridging developing over the eastern Pacific begins to nudge into the western US through the remainder of the week, allowing for a gradual warming and drying trend to prevail into next weekend. Whitlam && .AVIATION... Showers mainly impact areas east of the US-95 corridor through 18z, before spreading westward through the remainder of the day. Intermittent showers are expected between 21z Mon-12z Tue for KRNO- KMEV-KCXP, 00z Tue-12z Tue for KTVL-KTRK, and 20z Mon-03z Tue for KMMH. Expect mountain obscurement with periods of MVFR conditions under heavier showers. Isolated thunderstorms are possible for western NV this afternoon and evening. More typical westerly afternoon breezes are expected today, with gusts to 15-20 kts. FL100 winds increase overnight tonight through Tuesday ahead of another storm system moving into the region, yielding increased concerns for LLWS and mountain wave turbulence through early Tuesday afternoon. Whitlam && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$