Weather Discussion: More Stormy Weather | News
It is now the second wettest water year on record so far in Reno and more rain is in the forecast this coming week. It won’t be raining all day, but showers and thunderstorms are likely each afternoon and evening over the next several days. This is a similar pattern to what happened this past week.
Flash flooding, frequent lightning, gusty winds, and small hail are all possible with any storms that do develop. This is not the week to go boating or go for a long hike that takes all day. The key is having a way to seek shelter quickly if thunder roars, and trees don’t count as protection.
Temperatures, however, will near average with highs around 80 degrees. Storm chances start on Sunday and goes through at least Thursday. The models are split on next weekend. The GFS dries us out but the Euro keeps us active.
High pressure was in place on Saturday, allowing temperatures to warm. You can get thunderstorms under high pressure too, and a few storms popped up around Tahoe Saturday evening, but the Truckee Meadows stayed dry. The mountains can provide enough lift to get a few storms going when there is enough heat and instability.
Along with a ridge, there was a warm layer of air sitting above cooler air at the surface in the valley. This is called an inversion, and acts like a cap for thunderstorms. This kept storms from forming in the valley, and limited their potential in the Sierra, so they weren’t as strong.
One way to look at this is with lapse rates. They were much stronger at the surface compared to the mid levels of the atmosphere, which means it was cooling off quicker at the surface compared to the mid levels. This points to an inversion being in place.
The ridge will break down and the cap will be weakened as an area of low pressure moves in from the west late Sunday into Monday morning. The low will move in south of Tahoe and the flow around it will be out of the southeast. While the flow was out of the southwest on Saturday, providing us with dry air, southeasterly flow will do the opposite and bring in more moisture. Relative humidity, dewpoint, and precipitable water values will rise this week, and could even feel a little muggy out.
The low will get cut off from the jet stream and as a result will have a hard time leaving. A Rex Block could also set up, locking our stormy weather pattern in place this week. A Rex Block keeps a low over the southwestern part of the country, and a ridge will be to the north. This looks like a backwards S on a weather map.
Rain totals will vary greatly with some places getting hardly anything and others could see over a half inch. Where the data counts is at the airport for Reno. This past month wound up being the third wettest May on record in the Reno area with 2.44” of liquid precipitation falling at the airport.
Flash flooding occurs when a lot of rain falls within a short time frame. Burn scars and poor drainage areas are the most susceptible to flash flooding. Not only is it wise to go indoors when thunder roars, but to also turn around when you see standing water instead of driving through it. Oftentimes the water is much deeper than it appears.
