textproduct: Reno

KEY MESSAGES

* Very warm days prevail through Tuesday with temperatures near record highs.

* Dry conditions are expected through early this week with typical afternoon west breezes. A few stronger gusts may occur Tuesday afternoon in west central NV.

* Some cooling returns by mid-late week with isolated shower chances and periods of breezy winds.

DISCUSSION

Mother's Day will be on the warm side as building high pressure over the southwest US brings temperatures to their peak levels so far this year, with several valley areas in western NV surpassing 90 degrees. Sierra communities can expect highs near 80 degrees. Record highs are within reach at our primary climate sites (Reno NV and South Lake Tahoe CA)--see the Climate section below for each date's current record highs. Similar temperatures are expected each afternoon through Tuesday, with a few warmer valleys in west central NV approaching 95 degrees. Typical zephyr-type west-southwest breezes (gusts up to around 25 mph) are expected each afternoon through Tuesday.

The latest NWS HeatRisk forecast continues to show warmer valleys of western NV in the Moderate category, with the remainder of the region in the Minor category today through Tuesday. Remember to stay hydrated and limit exposure to the sun during the warmest parts of the day, especially if you have outdoor plans and are sensitive to heat. Also, use extra caution near rivers which remain cold and could be flowing fast, presenting a risk of hypothermia or loss of body control from the shock of sudden cold water exposure.

Dry weather is likely to prevail through the early part of this week. Increased heating will lead to cumulus formation each afternoon through Monday mainly from eastern Mono County to west central NV, but strong subsidence under the ridge should limit vertical growth.

Tuesday afternoon could present a more complex scenario as some higher resolution guidance sources are producing isolated showers over portions of far western-west central NV. Meanwhile, a deep layer of dry air remains in place below the high-based cloud layer, which would lead to potentially strong wind gusts (50+ mph) from seemingly weak-looking showers. Currently the guidance is having some difficulty in resolving specific surface and mid-level weather elements across western and west central NV, so while the risk of these enhanced gusts is present, the confidence in all the ingredients coming together remains on the low side.

For Wednesday-Thursday, confidence is high for temperatures cooling from their near-record levels as the upper ridge gives way to an area of low pressure arriving from the eastern Pacific. However, in terms of precipitation chances and wind, confidence is lower as timing differences continue with the track of this low, with a near-equal split among the ensemble guidance members between a faster passage on Wednesday vs. a slower passage on Thursday. First runs of higher-resolution guidance covering Wednesday afternoon seem to favor the faster scenario. In summary, a period of showers with isolated thunder remains in play as soon as Wednesday afternoon-night with higher chances (25-40%) favoring the Tahoe basin northward into northeast CA/northwest NV, while increased winds (gusts 30-40 mph) spread across much of western NV. We'll maintain the shower chances for Thursday as well to account for the potentially slower storm track, although this scenario would reduce the chances of enhanced wind gusts for either day.

From Friday through next weekend, confidence is higher for dry conditions returning as more of a zonal flow sets up across northern CA-NV. Temperatures won't be as warm compared to this weekend but should remain a few degrees above average (mid-upper 70s for lower elevations/upper 60s-near 70 for Sierra communities), with typical zepyhr-type breezes each afternoon. MJD

AVIATION

VFR conditions are expected at the main terminals through at least Tuesday, with potential density altitude concerns for western NV terminals due to very warm temperatures each afternoon. Southwest to west wind gusts of 20-25 kt are expected each afternoon through Tuesday mainly between 20Z-03Z. MJD

CLIMATE

Current record high temperatures for Reno, NV that have potential to be broken or tied (Today-Tuesday):

May 10: 88 F, set in 1934. May 11: 90 F, set in 2001 and 2013. May 12: 89 F, set in 1959 and 2013.

Current record high temperatures for South Lake Tahoe, CA that have potential to be broken or tied (Today-Tuesday):

May 10: 75 F, set in 2025. May 11: 78 F, set in 2013. May 12: 79 F, set in 1988 and 1996.

REV Watches/Warnings/Advisories

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