123 FXUS65 KREV 211718 CCA AFDREV Area Forecast Discussion...CORRECTED National Weather Service Reno NV 1018 AM PDT Wed Apr 21 2021 .UPDATE... Quick update to hoist a Lake Wind Advisory for Pyramid Lake. Winds are sustained at near 20 mph near Sutcliffe which is where the boat launch sites are. It is a little bit less at the Anaho site, but we expect the winds to remain quite breezy through the afternoon. Also, the winds are oriented along the long axis of the lake which would act to increase the chop with the longer fetch. Updates out. X && .PREVIOUS DISCUSSION... /Issued 253 AM PDT Wed Apr 21 2021/ SYNOPSIS... Shower coverage mainly south of Highway 50 this morning will diminish as breezy north winds spread drier air into the region. After a cooler day, warmer conditions return Thursday and Friday with more typical afternoon breezy conditions. A late season winter storm will bring strong winds and periods of valley rain and mountain snow this weekend into early next week. SHORT TERM... Latest satellite imagery showed the compact upper low finally beginning to track southward at a little faster clip as the next shortwave upstream approached the Pacific Northwest. Showers and associated gusty outflow winds along the I-80 corridor will gradually taper as new shower development occurs farther south from Alpine/Mono Counties eastward to Mineral/southern Churchill counties (as the deformation zone shifts southward). Isolated thunderstorms are still possible close to the core of the low, mainly later this morning into the afternoon near the Sierra crest, although overall shower coverage east of the crest will be diminishing during the afternoon, as steering winds push most of the showers out of the area (either west of the crest or into central/southern NV. It will be cooler today with breezy north winds and decreasing cloud cover from north to south. Areas of blowing dust in the Basin and Range should settle down early this morning as the very tight pressure gradient relaxes a bit. While temperatures will be cooler today and RH generally higher, the Chalfant/Hammil Valleys and the Swall Meadows area could still experience near critical fire weather conditions. Northerly flow will likely channel here with gusts 30-35 mph. A weak shortwave ridge moves across CA-NV Thursday and Friday with warmer daytime temperatures and dry conditions. Modest northwest winds aloft and good mixing will keep breezy winds going each afternoon/evening. So the enhanced chop today on Pyramid Lake will persist into Friday. Hohmann LONG TERM...Saturday through next week... A late season Pacific storm system will move into the region this weekend into early next week, bringing strong gusty winds, colder temperatures, valley rains and mountain snow. Forecaster confidence continues to increase regarding this pattern change. GFS and EC ensembles continue to increase the chances of seeing the storm make landfall in California and push precipitation into the Sierra and even into western Nevada on Sunday. There is a low chance (less than 25%) that the storm could split to the south, with much less impact to our area, but at this time it's most likely that this storm will hit. Winds will increase Saturday into Sunday, with widespread valley gusts up to 40-50 mph. Saturday's winds will be strongest north of US-50, then shift to south of US-50 on Sunday. Impacts to air travel, high-profile vehicles, and lake recreation are highly likely (90% chance), with a low chance (around 20%) of damaging winds. Some light precipitation will move into northeast California late Saturday, but the bulk of the moisture will push into the region on Sunday as the Pacific moisture plume moves inland. Latest model consensus has the most likely precipitation in the Sierra around 0.5- 1.0", with up to around 1.5" along the Sierra Crest. We should see some periods of shadowing and light spillover into western Nevada, with generally less than 0.10" into the valleys of western Nevada and up to 0.25" in northeast California. With snow levels coming down to around 5500ft Sunday night, we could see a few inches of snow down to Lake Tahoe level and higher amounts of 6-12" of snow at Sierra pass level. Several inches of snow are expected in the Eastern Sierra of Mono County as well, but the heaviest snow will likely be north of Tioga pass. Below normal temperatures are in store for Sunday and Monday, with highs in the 50s for western Nevada and 40s in the Sierra. Temperatures will start to warm back up to near average by the middle of next week as a ridge builds back over CA/NV. -Hoon AVIATION... Low pressure moving over the region will continue to bring scattered showers, pushing south through the day with mainly areas south of US-50 by later this morning. This includes a 30% chance for a dusting of snow around KMMH this morning. Periods of LLWS are also possible through this morning for KMMH, mainly before 15z. Brisk north winds are in store for today across the region with gusts up to 20-25kts. There is some blowing dust over west-central Nevada this morning around KNFL with minor reductions to visibility. Scattered showers will continue through the day in Mono-Mineral counties, although focus will shift mainly west of the crest with a slight chance of thunder for areas along and west of the Sierra Crest this afternoon. Quieter weather is expected for Thursday-Friday, with a stronger Pacific storm system moving into the region this weekend. This storm system will bring strong gusty winds, LLWS, mountain snow and valley rain. -Hoon && .REV Watches/Warnings/Advisories... NV...Lake Wind Advisory until 7 PM PDT this evening for Pyramid Lake in NVZ004. CA...None. && $$ For more information from the National Weather Service visit... http://weather.gov/reno