FXUS65 KREV 111012 AFDREV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 312 AM PDT THU APR 11 2013 .SYNOPSIS... LIGHT RAIN SHOWERS WILL END THIS MORNING OVER WESTERN NEVADA AS COLD FRONT PUSHES FARTHER SOUTH. DRY AND WARM CONDITIONS WILL RETURN FOR FRIDAY AND SATURDAY WITH INCREASING WINDS SATURDAY. A STRONGER STORM SYSTEM DROPPING SOUTH INTO THE WESTERN US WILL BRING WINDY CONDITIONS FOR SUNDAY WITH A CHANCE OF SHOWERS AND A SHARP DROP IN TEMPERATURES BY EARLY NEXT WEEK. && .SHORT TERM... RAIN SHOWERS HAVE MOVED ACROSS WESTERN NV OVERNIGHT INCLUDING THE RENO VICINITY. RAINFALL AMOUNTS HAVE GENERALLY BEEN 0.10 INCH OR LESS NORTH OF A RENO-FALLON LINE, EXCEPT FOR ONE RAWS SITE IN NORTHERN PERSHING COUNTY WHICH RECEIVED ALMOST 0.25 INCH. WATER VAPOR SATELLITE LOOP SHOWS A COMPACT JET STREAK MOVING ACROSS NORTHERN CA WHICH HAS PROVIDED ENOUGH FORCING FOR PRODUCING THESE SHOWERS. AS THIS JET STREAK CONTINUES TO MOVE SOUTH, THE PRECIP WILL END FROM NORTH TO SOUTH DURING THE NEXT FEW HOURS. FOR THE REST OF TODAY, DRIER AIR WITH TEMPS 5-10 DEGREES COOLER WILL PUSH IN BEHIND THE COLD FRONT WITH NORTHEAST WINDS AROUND 10-15 MPH ACROSS MUCH OF WESTERN NV. THE ONLY POSSIBLE EXCEPTION TO THE DRY CONDITIONS MAY BE ALONG THE SIERRA CREST IN ALPINE AND MONO COUNTIES AS ANOTHER WEAK SHORTWAVE IN THE EASTERN PACIFIC DIVES INTO CENTRAL CA THIS AFTERNOON. TERRAIN DRIVEN CONVERGENCE AND A SMALL DEFORMATION ZONE SHOULD LEAD TO SOME CUMULUS FORMATION ALONG THE CREST. A FEW BRIEF SHOWERS MAY DEVELOP IN THE LATE AFTERNOON, BUT CLOUD DEPTH WILL BE SHALLOW AS MODEL SOUNDINGS SHOW A CAP AND VERY DRY AIR ABOVE 650 MB. IN ADDITION, WITH PREVAILING NORTHEAST FLOW ALONG THE RIDGES, ANY ACTIVITY THAT MANAGES TO DEVELOP WILL PUSH WEST OF THE CREST BEFORE WEAKENING AROUND SUNSET. ON FRIDAY, FLAT RIDGE REDEVELOPS OVER CA-NV WITH GENERALLY LIGHT WINDS AND SCATTERED CIRRUS BANDS, WHILE TEMPS WARM UP TO THE LOWER 70S AGAIN FOR WESTERN NV. ON SATURDAY, THE RIDGE BECOMES SUPPRESSED FARTHER SOUTH AS COLD LOW PRESSURE MOVES ACROSS THE NWRN US NEAR THE CANADA BORDER, RESULTING IN SEVERAL DEGREES OF COOLING AND MORE WIDESPREAD HIGH CLOUDS ACROSS NERN CA-NWRN NV. IN LOWER ELEVATIONS FROM I-80 SOUTHWARD, HIGH TEMPS ON SATURDAY WILL BE SIMILAR TO FRIDAY AS INCREASED WINDS WITH GUSTS OF 30-35 MPH PRODUCE IMPROVED MIXING, ALTHOUGH HIGH ELEVATIONS WILL BE A FEW DEGREES COOLER. MJD .LONG TERM...SUNDAY THROUGH WEDNESDAY... FEW CHANGES WERE NECESSARY AS TROUGH WILL DOMINATE THIS PERIOD. THE ECMWF CONTINUES TO SHOW VERY GOOD CONSISTENCY OVER THE PAST FEW DAYS AND ITS ENSEMBLE MEAN HAS MOVED INTO ITS DETERMINISTIC DIRECTION. SO CONFIDENCE IS INCREASING THAT CONDITIONS WILL BE BELOW NORMAL WITH A CHANCE OF SHOWERS BEGINNING ACROSS THE FAR NORTH SUNDAY AND SPREADING TO ALL AREAS BY MONDAY. THE GFS/GEM CONTINUE TO SHOW A MORE EASTERN SOLUTION. HOWEVER THE ECMWF IS MAINTAINING A SLOWER MOVEMENT OF TROUGH WITH ITS MORE WESTWARD PLACEMENT AND HOLDS ONTO SHOWERS LONGER. DECIDED TO LEAN TOWARD THE ECMWF BECAUSE IT HAS BEEN DOING SO WELL LATELY AND HAS SHOWN PERSISTENCE. SO HAVE EXTENDED A SLIGHT CHANCE OF SHOWERS INTO TUE AND INTRODUCED SOME GHOST POPS FOR THE GRIDDED DATA SET ON WED TO ACCOUNT FOR A SLOWER DEPARTURE. GUSTY WINDS WILL ACCOMPANY SOUTHWARD PUSHING FRONT ON SUN-SUN NIGHT WITH ONE MORE DAY OF TEMPERATURES NEAR NORMAL. TEMPERATURES WILL BE BELOW NORMAL MON-TUE WITH THE INCREASING CLOUDS AND SHOWERS UNDERNEATH TROUGH. KATT && .AVIATION... SHORTWAVE WILL CONTINUE TO MOVE THROUGH WESTERN NV/EASTERN SIERRA EARLY THIS MORNING WITH WAVE EXITING THE REGION BY MIDDAY. BAND OF SHOWERS ACCOMPANYING THIS FEATURE WILL NOT RESULT IN ANY AIRPORT RESTRICTIONS BUT COULD OBSCURE HIGHER MT TOPS OF THE SIERRA WITH PERIODS OF WET RUNWAYS FOR THE TAF SITES AROUND THE TAHOE BASIN INCLUDING KRNO/KCXP THROUGH 15Z. AMOUNTS WILL BE LIGHT, GENERALLY CONFINED TO A FEW HUNDREDTHS OF AN INCH. AN ISOLATED LIGHTNING STRIKE IS POSSIBLE WITH BAND OF HEAVIER SHOWERS FROM KRNO-KNFL. A SECOND SHORTWAVE WILL MOVE THROUGH CA THIS AFTERNOON AND MAY PRODUCE ISOLATED SHOWERS ALONG THE SIERRA CREST SOUTH OF LAKE TAHOE. THESE SHOWERS SHOULD NOT AFFECT KMMH AS THEY WILL FAVOR THE WEST SLOPES OF THE SIERRA WHERE SURFACE TROUGH WILL BE SET UP. OTHERWISE A GENERAL NORTH OR NORTHEAST FLOW WILL PREVAIL WITH SPEEDS AT TAF SITES MOSTLY 10KT OR LESS TODAY. KATT && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)  FXUS65 KREV 281104 AFDREV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 304 AM PST WED JAN 28 2015 .SYNOPSIS... MOIST FLOW WILL KEEP CLOUD COVER OVER THE REGION THROUGH LATE THURSDAY. A FEW SHOWERS ARE POSSIBLE SOUTH OF HIGHWAY 50 THURSDAY INTO FRIDAY BEFORE DRIER CONDITIONS RETURN FOR THE WEEKEND. && .SHORT TERM... SOME BREAKS IN CLOUD COVER ARE ALLOWING FOR THE EARLY FORMATION OF FREEZING FOG IN THE MARTIS VALLEY. IT IS LIKELY THAT OTHER SIERRA LOCATIONS WILL ALSO SEE SOME FOG AS THESE BREAKS MOVE ACROSS THE SIERRA. IT DOES LOOK LIKE THERE WILL BE INTERMITTENT PERIODS OF INCREASING/DECREASING SKY COVERAGE SO EXPECT SOME FLUCTUATIONS IN FOG THICKNESS THROUGH THE NIGHT. THE POTENTIAL FOR MORE WIDESPREAD FREEZING FOG WILL INCREASE OVER THE NEXT COUPLE OF NIGHTS FOR TYPICAL LOCATIONS LIKE THE MARTIS AND SIERRA VALLEYS AS SKIES CLEAR ACROSS THE NORTHERN SIERRA. A VERY LOW AMPLITUDE RIDGE WILL BE IN PLACE TODAY WITH UPPER LEVEL MOIST FLOW KEEPING AMPLE CLOUD COVER OVER THE REGION. WHILE AN EXTREMELY ISOLATED HIGH ELEVATION SHOWER CANNOT BE RULED OUT, THE OVERALL CONDITIONS WILL BE DRY TODAY. AREA HIGH TEMPERATURES WILL NOT VARY WIDELY FROM SIERRA VALLEYS TO WESTERN NEVADA VALLEYS FOR THE NEXT COUPLE OF DAYS. TEMPERATURES WILL REACH THE LOW/MID 50S. SLIGHTLY COOLER CONDITIONS WILL OCCUR FRIDAY AS FLOW RESPONDS TO A DEEPENING LOW NEAR THE CA/NV/AZ BORDER SHIFTING MORE NORTHERLY. STILL, HIGHS WILL BE ABOVE SEASONAL AVERAGES HANGING AROUND 50 DEGREES IN THE SIERRA AND WESTERN NEVADA. SOME LIGHT PRECIPITATION WILL BE POSSIBLE AS THE LOW MEANDERS A BIT BEFORE DROPPING SOUTH INTO SOUTHERN ARIZONA. THESE LOW CHANCES WILL REMAIN SOUTH OF HIGHWAY 50 IN MONO AND MINERAL COUNTIES. DRIER FLOW RETURNS FOR THE WEEKEND WITH A MODERATELY AMPLIFIED RIDGE OFF THE CALIFORNIA COAST. BOYD .LONG TERM...SATURDAY THROUGH TUESDAY... NO SIGNIFICANT CHANGES WERE MADE TO THE CURRENT FORECAST. RIDGE AXIS IS EXPECTED TO MOVE OVER WESTERN NV SATURDAY, KEEPING THE REGION DRY WITH LIGHT NORTHEAST WINDS IN LOWER ELEVATIONS AND STRONGER RIDGE GUSTS OVER THE SIERRA. THIS NORTHEAST FLOW WITH INVERSION IN PLACE WILL LIMIT DAYTIME HEATING DESPITE LITTLE TO NO CLOUD COVER, KEEPING HIGHS GENERALLY IN THE LOWER TO MID 50S FOR WESTERN NV AND SIERRA VALLEYS. FOR SUNDAY AND MONDAY, THE RIDGE IS EXPECTED TO FLATTEN AS MOISTURE SPREADS INTO THE PACIFIC NORTHWEST. WEAK SHORTWAVE ENERGY MOVING THROUGH THIS MOIST FLOW IS TRACKING A LITTLE FARTHER SOUTH ON THE LATEST GUIDANCE, WHICH WOULD INCREASE MID AND HIGH LEVEL CLOUD COVER ACROSS MOST OF THE REGION SUNDAY THROUGH MONDAY. PRECIPITATION POTENTIAL IS STILL LIMITED DUE TO MARGINAL FORCING, BUT SOME LIGHT SHOWERS ARE POSSIBLE OVER NORTHEAST CA-NORTHWEST NV SUNDAY NIGHT, AND EXTENDING SOUTH TO NEAR INTERSTATE 80 BY MONDAY. THE SOUTHERN EXTENT OF SHOWER POTENTIAL IS QUITE UNCERTAIN AT THIS TIME, SO CURRENT CONFIDENCE LEVEL FOR ANY MEASURABLE PRECIP SPREADING SOUTH OF A SUSANVILLE-GERLACH LINE IS LOW. TEMPERATURES ON SUNDAY ARE LIKELY TO INCREASE BY A FEW DEGREES AS INVERSION WEAKENS AND FLOW BECOMES WEST, ALTHOUGH CLOUD COVER WILL PREVENT FURTHER HEATING ESPECIALLY NORTH OF SUSANVILLE AND GERLACH. MONDAY WILL BE A LITTLE COOLER ALTHOUGH THE AMOUNT OF COOLING WILL DEPEND ON THE EVENTUAL TRACK OF THE SHORTWAVE MOVING ACROSS THE REGION. BY MONDAY NIGHT, OVERALL PRECIP CHANCES SHOULD DIMINISH AS SHORTWAVE DEPARTS THE REGION. THERE IS A SMALL POSSIBILITY FOR THIS WAVE TO DIG A BIT SOUTH WITH A NARROW BAND OF SHOWERS FORMING IN WEST CENTRAL NV, BUT THE MAJORITY OF THE GUIDANCE DATA PUSHES THIS SYSTEM AND PRECIP CHANCES FARTHER TO THE EAST. BY TUESDAY, RIDGE RETURNS TO THE WEST COAST WITH DRY CONDITIONS PREVAILING. THE AMPLITUDE OF THE RIDGE AXIS VARIES WHICH WOULD AFFECT DAYTIME TEMPS. THE LATEST GFS SHOWS A SHARPER AXIS OFF THE COAST WHICH WOULD LEAD TO COOLER HIGHS FOR THE REGION WITH INCREASING NORTHEAST FLOW ESPECIALLY FOR RIDGES. THE ECMWF AND MOST OF THE ENSEMBLE DATA FAVORED A LOWER AMPLITUDE RIDGE, WHICH WAS INDICATED BY THE INHERITED FORECAST. WE WILL KEEP THIS FORECAST INTACT FOR NOW WHICH WOULD KEEP HIGHS IN THE 50S FOR MOST OF THE REGION. MJD && .AVIATION... CLEARING SKIES AND LEFTOVER MOISTURE FROM TUESDAY'S RAIN ALLOWED FZFG TO ROLL INTO KTRK BETWEEN 200 AND 230 AM. WITH NO SIGNIFICANT CLOUDS UPSTREAM WE WILL KEEP FZFG GOING UNTIL LATER THIS MORNING. CONDITIONS APPEAR FAVORABLE FOR REDEVELOPMENT OF FZFG AROUND KTRK EASTERN SIERRA/PLUMAS COUNTIES FOR EARLY THURSDAY MORNING MAINLY FROM 09-17Z. OTHERWISE VFR CONDITIONS WITH LIGHT EAST WINDS ARE EXPECTED TODAY THROUGH THURSDAY. AT KCXP WHERE EAST FLOW IS TYPICALLY ENHANCED, SPEEDS WILL BE A LITTLE HIGHER IN THE 10-15 KT RANGE MAINLY BETWEEN 21-03Z BOTH DAYS. MJD && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)  FXUS65 KREV 281114 AFDREV AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RENO NV 314 AM PST WED JAN 28 2015 .SYNOPSIS... MOIST FLOW WILL KEEP CLOUD COVER OVER THE REGION THROUGH LATE THURSDAY. A FEW SHOWERS ARE POSSIBLE SOUTH OF HIGHWAY 50 THURSDAY INTO FRIDAY BEFORE DRIER CONDITIONS RETURN FOR THE WEEKEND. && .SHORT TERM... SOME BREAKS IN CLOUD COVER ARE ALLOWING FOR THE EARLY FORMATION OF FREEZING FOG IN THE MARTIS VALLEY. IT IS LIKELY THAT OTHER SIERRA LOCATIONS WILL ALSO SEE SOME FOG AS THESE BREAKS MOVE ACROSS THE SIERRA. IT DOES LOOK LIKE THERE WILL BE INTERMITTENT PERIODS OF INCREASING/DECREASING SKY COVERAGE SO EXPECT SOME FLUCTUATIONS IN FOG THICKNESS THROUGH THE MORNING. THE POTENTIAL FOR MORE WIDESPREAD FREEZING FOG WILL INCREASE OVER THE NEXT COUPLE OF NIGHTS FOR TYPICAL LOCATIONS LIKE THE MARTIS AND SIERRA VALLEYS AS SKIES CLEAR ACROSS THE NORTHERN SIERRA. A VERY LOW AMPLITUDE RIDGE WILL BE IN PLACE TODAY WITH UPPER LEVEL MOIST FLOW KEEPING AMPLE CLOUD COVER OVER THE REGION. WHILE AN EXTREMELY ISOLATED HIGH ELEVATION SHOWER CANNOT BE RULED OUT, THE OVERALL CONDITIONS WILL BE DRY TODAY. AREA HIGH TEMPERATURES WILL NOT VARY WIDELY FROM SIERRA VALLEYS TO WESTERN NEVADA VALLEYS FOR THE NEXT COUPLE OF DAYS. TEMPERATURES WILL REACH THE LOW/MID 50S. SLIGHTLY COOLER CONDITIONS WILL OCCUR FRIDAY AS FLOW RESPONDS TO A DEEPENING LOW NEAR THE CA/NV/AZ BORDER, SHIFTING MORE NORTHERLY. STILL, HIGHS WILL BE ABOVE SEASONAL AVERAGES HANGING AROUND 50 DEGREES IN THE SIERRA AND WESTERN NEVADA. SOME LIGHT PRECIPITATION WILL BE POSSIBLE AS THE LOW MEANDERS A BIT BEFORE DROPPING SOUTH INTO SOUTHERN ARIZONA. THESE LOW CHANCES WILL REMAIN SOUTH OF HIGHWAY 50 IN MONO AND MINERAL COUNTIES. DRIER FLOW RETURNS FOR THE WEEKEND WITH A MODERATELY AMPLIFIED RIDGE OFF THE CALIFORNIA COAST. BOYD .LONG TERM...SATURDAY THROUGH TUESDAY... NO SIGNIFICANT CHANGES WERE MADE TO THE CURRENT FORECAST. RIDGE AXIS IS EXPECTED TO MOVE OVER WESTERN NV SATURDAY, KEEPING THE REGION DRY WITH LIGHT NORTHEAST WINDS IN LOWER ELEVATIONS AND STRONGER RIDGE GUSTS OVER THE SIERRA. THIS NORTHEAST FLOW WITH INVERSION IN PLACE WILL LIMIT DAYTIME HEATING DESPITE LITTLE TO NO CLOUD COVER, KEEPING HIGHS GENERALLY IN THE LOWER TO MID 50S FOR WESTERN NV AND SIERRA VALLEYS. FOR SUNDAY AND MONDAY, THE RIDGE IS EXPECTED TO FLATTEN AS MOISTURE SPREADS INTO THE PACIFIC NORTHWEST. WEAK SHORTWAVE ENERGY MOVING THROUGH THIS MOIST FLOW IS TRACKING A LITTLE FARTHER SOUTH ON THE LATEST GUIDANCE, WHICH WOULD INCREASE MID AND HIGH LEVEL CLOUD COVER ACROSS MOST OF THE REGION SUNDAY THROUGH MONDAY. PRECIPITATION POTENTIAL IS STILL LIMITED DUE TO MARGINAL FORCING, BUT SOME LIGHT SHOWERS ARE POSSIBLE OVER NORTHEAST CA-NORTHWEST NV SUNDAY NIGHT, AND EXTENDING SOUTH TO NEAR INTERSTATE 80 BY MONDAY. THE SOUTHERN EXTENT OF SHOWER POTENTIAL IS QUITE UNCERTAIN AT THIS TIME, SO CURRENT CONFIDENCE LEVEL FOR ANY MEASURABLE PRECIP SPREADING SOUTH OF A SUSANVILLE-GERLACH LINE IS LOW. TEMPERATURES ON SUNDAY ARE LIKELY TO INCREASE BY A FEW DEGREES AS INVERSION WEAKENS AND FLOW BECOMES WEST, ALTHOUGH CLOUD COVER WILL PREVENT FURTHER HEATING ESPECIALLY NORTH OF SUSANVILLE AND GERLACH. MONDAY WILL BE A LITTLE COOLER ALTHOUGH THE AMOUNT OF COOLING WILL DEPEND ON THE EVENTUAL TRACK OF THE SHORTWAVE MOVING ACROSS THE REGION. BY MONDAY NIGHT, OVERALL PRECIP CHANCES SHOULD DIMINISH AS SHORTWAVE DEPARTS THE REGION. THERE IS A SMALL POSSIBILITY FOR THIS WAVE TO DIG A BIT SOUTH WITH A NARROW BAND OF SHOWERS FORMING IN WEST CENTRAL NV, BUT THE MAJORITY OF THE GUIDANCE DATA PUSHES THIS SYSTEM AND PRECIP CHANCES FARTHER TO THE EAST. BY TUESDAY, RIDGE RETURNS TO THE WEST COAST WITH DRY CONDITIONS PREVAILING. THE AMPLITUDE OF THE RIDGE AXIS VARIES WHICH WOULD AFFECT DAYTIME TEMPS. THE LATEST GFS SHOWS A SHARPER AXIS OFF THE COAST WHICH WOULD LEAD TO COOLER HIGHS FOR THE REGION WITH INCREASING NORTHEAST FLOW ESPECIALLY FOR RIDGES. THE ECMWF AND MOST OF THE ENSEMBLE DATA FAVORED A LOWER AMPLITUDE RIDGE, WHICH WAS INDICATED BY THE INHERITED FORECAST. WE WILL KEEP THIS FORECAST INTACT FOR NOW WHICH WOULD KEEP HIGHS IN THE 50S FOR MOST OF THE REGION. MJD && .AVIATION... CLEARING SKIES AND LEFTOVER MOISTURE FROM TUESDAY'S RAIN ALLOWED FZFG TO ROLL INTO KTRK BETWEEN 200 AND 230 AM. THIS FOG DISPERSED MOMENTARILY AROUND 3 AM AS A BAND OF CLOUDS MOVED OVERHEAD, BUT WITH FEW SIGNIFICANT CLOUDS UPSTREAM WE WILL KEEP MENTION OF FZFG THROUGH LATER THIS MORNING. CONDITIONS APPEAR FAVORABLE FOR REDEVELOPMENT OF FZFG AROUND KTRK EASTERN SIERRA/PLUMAS COUNTIES FOR EARLY THURSDAY MORNING MAINLY FROM 09-17Z. OTHERWISE VFR CONDITIONS WITH LIGHT EAST WINDS ARE EXPECTED TODAY THROUGH THURSDAY. AT KCXP WHERE EAST FLOW IS TYPICALLY ENHANCED, SPEEDS WILL BE A LITTLE HIGHER IN THE 10-15 KT RANGE MAINLY BETWEEN 21-03Z BOTH DAYS. MJD && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)  FXUS65 KREV 022155 AFDREV Area Forecast Discussion National Weather Service Reno NV 255 PM PDT Sun Oct 2 2016 .SYNOPSIS... A cold trough moves into the West Coast today bringing gusty winds and temperatures well below seasonal averages along with the threat for lower valley freezes through mid-week. Valley rain and mountain snow showers are expected tonight and Monday night, with light snow accumulations possible over the Sierra passes this evening. Temperatures will warm back to near average by Friday. && .SHORT TERM... The main forecast concerns today are winds and humidities through this evening (mainly along/south of I-80), possible slick conditions over northern Sierra passes this evening, and sub-freezing temperatures for the lower valleys of western Nevada in the next few nights. Low pressure is dropping into northern California this afternoon and a wind shift has moved into western Nevada. However, little change in temperature or moisture has accompanied the shift so believe the main surface front to be with a band of precipitation (and solid wind shift/temperature change) nearing the northern Sierra early this afternoon. Some light rain has moved into Lassen and Plumas Counties this afternoon with a wet road indicated by web cams over Fredonyer Summit. Wind-wise, gusts between 25 and 35 mph (locally 40-45 mph) are widespread for eastern California and far western Nevada this afternoon. These winds should continue well into evening. However, humidities should begin to recover (and already have north of Tahoe in CA) as colder air filters into the region. For more, see the fire weather discussion below. Precipitation-wise, the initial frontal band of precipitation should go through quickly. Because precipitation is moving into the northern Sierra in the daytime, roads should remain mostly wet even over the crest (where snow will fall) due to well above freezing road surfaces. The main concern is between about sunset and 11 PM in the northern Sierra (down to about Ebbetts Pass) when widespread snow showers are expected under the upper low. The HRRR model continues to show locally heavy convective showers. However, it is hard to predict where narrow heavier bands will form and threaten slushy accumulations over Tahoe/Alpine County passes. Motorists should be prepared for slow travel over I-80, US 50, and for Mt Rose highway if they must wait until after dark to travel. Showers should taper off rapidly by midnight in the northern Sierra as the upper trough axis passes to the east. Any slushy conditions in the northern Sierra should abate quickly once showers taper off. Outside of the northern Sierra, only a brief shot at some light showers is expected tonight mainly just ahead of the trough axis. Turning to freezing temperature concerns, the latest HRRR is casting doubt that winds will calm down sufficiently or skies will remain clear long enough for a widespread freeze (locally defined as 30 degrees or less) in western Nevada tonight. Still, with the colder air filtering in valley temperatures should fall into the 30s to around 40 even if they remain mixed so it won't take much for a dip to 30 degrees or so for a couple hours. Therefore, the freeze warning for suburban and outlying valleys of far western NV will remain up for late tonight and Monday morning. Monday, a period of warm air advection/isentropic ascent is expected Monday afternoon and evening. This will bring the threat for some light showers, with snow levels rising generally above 7000 feet by late in the day. No road impacts are expected as the showers should be fairly light and the time of day is not ideal for road accumulations. Another brush-by system could bring a few more showers north of I-80 Tuesday. However, the main focus will be late Tuesday night and Wednesday morning temperatures for the lower valleys of northeast California and western Nevada. Tuesday morning looks a bit mixed up with a moist low level atmosphere so widespread freezing temperatures are not expected. Wednesday, and especially Thursday morning is a different story as drier air begins to filter into the area with slackening winds. At this time, it looks like Wednesday and/or Thursday morning will finally bring widespread below freezing temperatures to many areas of western Nevada. Snyder .LONG TERM...Thursday through Sunday... The long-term forecast calls for dry conditions Thursday through Sunday with the storm track north of the Oregon border. Model simulations do show weak impulses crossing the Sierra and western NV from west to east which could create periods of mid-to-high level cloudiness, mainly north of highway 50. There is a chance one of these impulses could bring a period of showers north of Susanville, but overall moisture looks to be quite limited so we maintained the chances for precipitation less than 15%. Some model simulations advertise a Pacific trough approaching the west coast Sunday which could bring an increase in moisture to the Sierra by Sunday night (a week from tonight), but this is a minority opinion. A slow warming trend of afternoon highs is forecast Thursday through Saturday or Sunday, although cloud thickness is a variable that could possibly temper that trend. Highs for Saturday and Sunday could warm into the mid to upper 70s in western NV and upper 60s to low 70s for Sierra communities. JCM && .AVIATION... A cold front passage is creating gusty west winds through this evening with peak gusts 30-40 kts from the lee of the Sierra out into western Nevada and far northeast California. Expect Sierra ridges to see gusts up to 60 kts through this evening along with moderate turbulence near and in the lee of the Sierra. A mix of rain and snow this evening could bring an inch or so of slushy accumulation to KTRK and KTVL. Cigs/vsbys into the MVFR/IFR range in the northern Sierra and northeast California are also expected through this evening. To the east and south rain and snow showers will be more scattered in nature but with IFR conditions possible near the Sierra crest in Mono county. VFR conditions are likely in western Nevada...but with some mountain obscurations. Snow in the Sierra will taper off to showers by midnight. Showers could linger into Monday as well and possibly Monday night north of I-80. Ceilings should improve Monday and winds will be lighter. Light precipitation is possible north of I-80 Tuesday and Wednesday...but conditions should be no worse than MVFR. 11/20 && .FIRE WEATHER... Gusty winds will continue into the early evening hours, as a cold front pushes through the region. Red Flag Warning remains in place for Mono-Alpine-Southern Lyon and Mineral Counties through 6PM. Moisture is increasing to the north of Reno-Tahoe, with precipitation and clouds already moving into the Truckee-Tahoe area. Wind gusts of 35-45 mph have been observed so far this afternoon for all areas, but the strongest winds have been mainly south of Carson City and down to Mammoth Lakes. Drier conditions exist south of Carson City with humidity in the low teens and even down to near 5% as you get near Mammoth Lakes/Benton/Bishop. Areas of critical conditions have also expanded slightly further north to near Minden/Gardnerville where firefighters are responding to a new wildfire near Dresslerville and Highway 395. Low pressure moving into northern CA/NV today will bring moisture and showers into the Northern Sierra and Lake Tahoe Basin through this evening. Snow levels will drop to around 5500-6000 feet this evening, bringing light snow accumulations of up to a few inches to the Northern Sierra above 7000 feet (mainly north of Ebbetts Pass all the way north to Lassen Park and the Warner Mountains. Breezy northwest flow will continue over the next couple days with temperatures slowly warming each day. Lighter winds are expected by Wednesday and Thursday as high pressure builds back over the region. Hoon && .REV Watches/Warnings/Advisories... NV...Freeze Warning from 2 AM to 8 AM PDT Monday NVZ003. Red Flag Warning until 6 PM PDT this evening NVZ459. Lake Wind Advisory until 8 PM PDT this evening for Lake Tahoe in NVZ002. Lake Wind Advisory until 8 PM PDT this evening for Pyramid Lake in NVZ004. CA...Freeze Warning from 2 AM to 8 AM PDT Monday CAZ071. Red Flag Warning until 6 PM PDT this evening CAZ273. Lake Wind Advisory until 8 PM PDT this evening for Lake Tahoe in CAZ072. && $$ For more information from the National Weather Service visit... http://weather.gov/reno  FXUS65 KREV 231130 AFDREV Area Forecast Discussion National Weather Service Reno NV 330 AM PST Thu Nov 23 2017 .SYNOPSIS... Very mild conditions will prevail through Saturday with a few record highs threatened. Most areas will remain dry although very light rain is possible Thursday in northeast California and far northwest Nevada. Saturday is expected to be very windy ahead of a strong cold front which will bring snow to the Sierra and northeast California Sunday and Sunday night. Expect travel delays transiting the Sierra due to slick driving conditions and higher post holiday traffic volume. It will be much colder early next week. && .SHORT TERM... The forecast remains on track with very few model differences from previous runs. Currently, some light rain is falling over northern Lassen County through northern Washoe County as a weak boundary remains draped in that vicinity. This boundary is projected to shift southward through the morning hours bringing a hundredth or two of rain as far south as the Tahoe Basin by late morning. Otherwise, precipitation washes out as the boundary loses support. Additionally, cloud cover associated with the boundary will limit fog formation in Sierra Valley and around Truckee this morning. Still, some pockets of freezing fog will be possible where cloud cover remains minimal in Sierra valleys. After a relatively benign Thanksgiving Day and Black Friday, winds begin to increase Saturday as a potent Pacific storm moves towards the region. Upper level jet wind projections show a larger area of 100+ knots with a maximum around 150 knots superimposed over the Sierra. This will translate to strong gusty surface winds for the region, especially for downslope areas along and west of Highway 395. The current wind forecast continues to have strong gusts to 60 mph along the Sierra Front with ridge winds topping 100 mph. Expect some travel restrictions for high profile vehicles especially through wind prone locations like Highway 395 in Washoe Valley and from Doyle to Susanville. A High Wind Watch remains in effect for much of the region. Winds will drop, especially for Sierra valleys, as precipitation moves into the region Saturday night. However, shadowed locations like the Sierra Front will likely see gusty conditions continuing through the night into Sunday. Boyd .LONG TERM...Sunday through Tuesday... The focus remains on the strong cold front to move through Sunday night and potential late holiday weekend travel impacts as a result. It still looks windy for Sunday as more moisture moves into the region. How strong the winds are Sunday is up for debate. A faster solution like the GFS has more moisture into the Sierra and therefore dampening the mountain wave a bit. This would result in breezy winds, but nothing excessive and lighter than Saturday evening, at least north of highway 50. Slower like the EC keeps high winds into Sunday afternoon. Despite the timing differences, the overall impact for snowfall in the Sierra looks the same. Snow levels will start 8-9000 feet, then gradually fall about 1-2000 feet into Sunday evening before crashing with the cold front. Most of the moisture remains ahead of the front, which will keep the heaviest accumulations above about 7000 feet or so. Still, several inches of snow over the major Sierra passes of Donner and Echo is likely. Lighter amounts down to 5000- 5500 feet. Spillover into Western Nevada is not ideal, but there will likely be some at least for the Sierra Front and 395 corridor. Strong SW winds aloft with good speed shear and strong frontal forcing are favorable. However, the instability and moisture is not that deep, only up to 600 mb or so which is unfavorable. Will keep amounts light beyond the east slopes of the Sierra. Behind the front Monday it will be much colder, but nothing abnormal for late November. Winds will also diminish behind the front and showers look to rapidly diminish as well as much warmer temps aloft stabilize the atmosphere. The cooler temps will continue into midweek with temperatures near seasonal averages overall as a low to moderate amplitude ridge moves overhead. It does appear overnight lows may be a little cooler than average while highs are a little above. && .AVIATION... MVFR visibility restrictions have occurred early this morning at TRK. Expect variable fog thickness through the night as mid/high clouds intermittently pass over the terminal. Overall, the depth of fog and duration is not expected to be as thick/long as yesterday, but periods of IFR remain possible through the morning. Cloud cover should thicken by late morning as a weak boundary drops southward along the Sierra. This boundary could produce a hundredth or two of rain for Sierra terminals. Otherwise, ridge winds continue to gust around 50kts creating some light to moderate mechanical turbulence. These winds will continue today through Friday before increasing substantially as a potent Pacific storm nears the region. Strong mountain waves are expected Saturday and Sunday with severe turbulence likely. Surface gusts are forecast to meet and exceed 50 kts at times. Anticipate LLWS as well. Precipitation will begin as rain through Flight Level 14000ft MSL Saturday night. Expect periods of IFR rain and ultimately snow Sunday and Sunday night; periods of MVFR Cigs will be possible for western Nevada terminals. Snow levels will fall gradually through Sunday reaching ridge level. A strong cold front is projected to bring snow levels down to near western Nevada valley floors by Monday morning. Boyd && .REV Watches/Warnings/Advisories... NV...High Wind Watch from Saturday morning through Sunday afternoon NVZ003-005. High Wind Watch from Saturday morning through Saturday evening NVZ002. CA...High Wind Watch from Saturday morning through Sunday afternoon CAZ070-071-073. High Wind Watch from Saturday morning through Saturday evening CAZ072. && $$ For more information from the National Weather Service visit... http://weather.gov/reno