textproduct: Reno

KEY MESSAGES

* Light winds, valley inversions, and dry conditions will continue through midday Thursday for all valleys with freezing fog for Sierra Valleys and Mono Lake.

* Ridge winds will increase Thursday into Saturday along with low chances for showers in the Sierra and portions of western Nevada.

* Saturday will be the coldest and windiest day of the week with hazardous wind chills for backcountry areas.

DISCUSSION

The grey, gloomy skies will persist through the end of the week until a dry cold front clears the skies over the weekend. Although, our brief break from the sun doesn't even compare to the persistent freezing fog that has plagued the Mono Lake region for much of the month with little reprieve. Here's what will bring some changes to the weather over the weekend and into early next week.

A cutoff low along the CA coast is the reason we're all clouded over today, but this storm won't bring much meaningful weather to us other than the cloud cover. It's forecast to drop southward through the weekend, leaving us with very low chances for showers tonight into Thursday across the high Sierra in Mono County. While we will see an uptick in breezes along the ridge tonight, the more "productive" winds will arrive Friday into Saturday. A dry, fast- moving trough drops through the Great Basin Friday into Saturday bringing northeast/east winds (gusts 20-30 mph) that should help to scour out the stagnant pockets of inversions in most areas, and hopefully for our friends in Mono county too! There are some low showers chances that accompany this northerly push of cold air through the region, but the majority of the shower potential will remain for areas south of Highway 50. For context, there is a 10-15% chance of 0.01" in Hawthorne and a 20-30% chance of that near Mammoth and June Lakes. There could be localized slick conditions, so just be aware that it won't be as bone dry as of late!

Saturday will feel quite brisk and chilly overall with the breezes and the colder air (about 10 degrees colder!). With wind gusts 50-60 mph for the high terrain, wind chills will dip into the single digits. Prepare accordingly if you have backcountry and/or resort recreation plans. It will be a far cry from the milder temperatures we saw over the holiday weekend. After Saturday we will see a gradual warming and drying trend as we start the next week.

While there are some mixed signals for the extended forecast, it does look there is a hint of hope for a more progressive pattern. The GFS/EC ensembles for IVT do show higher probabilities (50-70%) of IVT landfall along the Pacific Northwest coast for the end of the month and into early February. Signals do appear to drift a bit further south, into the Sierra area by early February, but it may be a bit early to tell. The ensemble clusters also bring some pessimism to the pattern change with only 17% of solutions showing a trough over the Eastern Pacific, while the remainder hold on to the West Coast ridging signal. Fingers crossed the storm track can barrel some more meaningful precipitation into the West soon!

-Edan

AVIATION

VFR conditions and light surface winds continue for area TAF sites through tonight. Freezing fog has a 10-15% chance to form again tomorrow morning at KTRK, but the upper level clouds may win out and disturb its formation like this morning.

Haze and poor mixing will lead to reduced slantwise visibility early Thursday, but there is potential for improved mixing by late afternoon. A quick system moves through Thursday, delivering 20-30% chances for a light rain shower for KMMH.

Increased FL100 winds Friday into Saturday will result in bumpy flying conditions through early Sunday morning.

-Edan

REV Watches/Warnings/Advisories

NV...None. CA...None.