textproduct: Reno

KEY MESSAGES

* Warm with breezy afternoons through Thursday, elevated fire weather concerns.

* Critical fire weather concerns for W.Nevada due to gusty winds with a strong cold front on Friday & Saturday.

* Temperatures cooling 10-20 degrees below average over the weekend with light showers possible.

DISCUSSION

* TEMPERATURES: Today we will embark upon the beginning of a cooling trend, with today's highs a couple degrees cooler than yesterday's. Cooling will be even more pronounced into the weekend as a cold front approaches, which is more reminiscent of April weather patterns than late June. You may be wondering what the strong late-June cooldown might be attributed to? An upper low that currently spins over the Gulf of Alaska promises to head south toward the Pacific Northwest, and along with it will arrive the cooler weather. For today, the influence is far enough away that we will only see the aforementioned slight cooling. For Friday, cooler temperatures than Thursday, which will actually be cooler than seasonal averages before the system fully arrives. By Saturday, widespread 70s across western Nevada and 60s across the Sierra valleys and Tahoe Basin. Even overnight lows across the Sierra valleys will dip to near or below freezing for 2-5 hours Saturday night into Sunday morning. Sensitive vegetation will likely need to be covered to prevent frost from forming. Sunday will be the coolest day of the weekend, nearly wiping all 80+ degree readings from the region, with the exception of the Chalfant Valley. Warming resumes for Monday, with 80 degree readings returning to western Nevada and northeastern California, and 70s for the Sierra communities.

* WINDS: Winds will largely be out of the west, with west- northwest winds turning northerly by late afternoon Saturday into Sunday. For today, expect typical afternoon gusts of 20-25 mph. Thursday, an uptick in the typical afternoon breezes will bring gusts 25-30 mph, mostly over the Basin and Range. As such, a Lake Wind Advisory has been issued for Lahontan and Rye Patch Reservoirs and Pyramid Lake. Friday, things start to get more interesting as the low drops into Washington state, thus drawing nearer. Gusts to 40 mph with sustained 20-25 mph winds will create choppy lakes, turbulent air travel, and blowing dust for road travelers across the Basin and Range. Gusts along the Sierra ridges will reach 60 mph for Friday. Going into Saturday, the center of circulation associated with the upper low drops into Oregon, dragging higher gusts with it. Ridges will see gusts to 80 mph, with sustained winds in the Sierra Front of 20-25 mph and gusts of 45 mph. For Friday and Saturday, a Red Flag Warning has been issued for the Sierra Front and Basin and Range, see details in the Fire Weather section of the discussion below, and the Red Flag Warning product. Sunday, we see light winds returning, with a northerly direction to reinforce the cooler air mentioned above.

* PRECIPITATION: With the source region, timing, and placement of this low, moisture with this system will be limited. Chances will start increasing along the Oregon border overnight Thursday into Friday. Modoc County into northern Washoe will see chances 30-50%, with some chances around 10-20% as far south as I-80. Saturday, chances are found across the same areas, but the range expands 20-60%, with the best chances still along the Oregon border. QPF remains low (0.01-0.02 inches), with best chances for wetting rains along the Oregon border for Saturday (10-15%). The overnight hours of Saturday into Sunday may also bring light snow showers with the cooler temperatures dropping snow levels to around 7500-8000 feet for the northern Sierra. Showers will be on the way out by Sunday afternoon, heading to the east.

The return to warming arrives with the new week, along with the return to typical afternoon breezes.

HRICH

AVIATION

* VFR conditions with typical westerly afternoon breezes today and Thursday. Gusts today will range 20-25 kts, and increasing to 30-35 kts for Friday.

* A strong, spring-like cold front will bring gusty winds to area terminals Friday and Saturday, where gusts will range 35-45 kts. Additional hazards include LLWS, mountain waves, and visibility reductions for KLOL, KNFL, KHTH due to blowing dust. HRICH

FIRE WEATHER

* Unusually strong cold front for late June projected to bring areas of critical fire weather conditions Friday and Saturday. Red Flag Warnings now in effect for the Sierra Front eastward into the Hwy 95 corridor.

* High confidence in seeing sustained winds 20-30 mph with gusts above 40 mph both days, with a W/SW direction on Friday and W/NW on Saturday. While Friday appears to be a widespread gust- driven day, Saturday potentialseems nudged toward isolated higher gusts with higher widespread sustained winds. Looking more like an April- like pattern than late June.

* For areas in the warning along and north of a Carson City to Lovelock line, including Reno, the humidity may be just above RFW criteria, around 15-25% for afternoon minimums. But with plenty of dry fuels/grasses and recent significant lightning event last Friday with holdover potential, winds of this magnitude may lessen the impact of slightly higher RH.

* E.Sierra fire weather zones are also expected to see these same strong winds with ridgetops seeing wind gusts exceeding 80 mph. However, fuels have not been reported to be critical and minimum RH is expected to be around 30-40%. The exception could be along Hwy 6 and 395 below 7000' in Mono County where RH could dip into the teens.

* Humidity recoveries Friday night into Saturday morning look good (45-75%), but winds will remain breezy for mid-slopes and ridges.

-Chris/Fuentes/HRICH

REV Watches/Warnings/Advisories

NV...Red Flag Warning from 11 AM Friday to 11 PM PDT Saturday NVZ420.

Lake Wind Advisory from 11 AM Friday to 2 AM PDT Saturday NVZ001>004.

Lake Wind Advisory from 2 PM to 11 PM PDT Thursday NVZ004.

Red Flag Warning from 11 AM Friday to 11 PM PDT Saturday NVZ423- 429.

CA... Lake Wind Advisory from 11 AM Friday to 2 AM PDT Saturday CAZ071- 072.