textproduct: Reno

KEY MESSAGES

* Widespread minor HeatRisk with areas of Moderate HeatRisk in the Nevada Basin and Range is expected today as temperatures become milder going into the weekend.

* Thunderstorm activity continues today, bringing impacts to fire, recreation, travel and aviation.

* A warming trend resumes for next week, with a return of typical afternoon breezes.

DISCUSSION

According to the latest RAP analysis of the upper air pattern, the CWA sits between a weakening upper ridge and a Pacific trough moving closer to the West Coast this morning. Model guidance projects the aforementioned trough moving over the region later today while pushing the ridge out to the east. With this setup aloft and the associated weather system moving through the region, high temperatures expect to decrease today by about 5-10 degrees compared to Thursday in some locations. NE CA and W NV valleys should see highs in the middle 80s to lower 90s range and Sierra communities will have high temperatures in the middle 70s to lower 80s range. While widespread Minor HeatRisk concerns are expected for the region, portions of the NV Basin and Range such as Hawthorne and Lovelock may see Moderate HeatRisk continue with daytime highs still warming up to the middle 90s. Generally west to northwest gusty winds are forecast today with gusts up to around 25-35 mph.

This trough not only will bring some relief to the recent heat, but cause also increased shower and thunderstorm chances today compared to those from Thursday. The latest radar returns show some lingering showers mostly in NE CA this morning. Recent runs of CAMs support around a 15-30% for isolated showers in Modoc, Lassen, and Plumas Counties the early morning hours with portions of NV north of I-80 having ~15% or less as well. By mid-morning, showers in NE CA and adjacent Northern Washoe become a bit more scattered before precipitation chances increase to around 40-60% in these areas. Forecast guidance is also showing around a 40-80% chance for showers beginning around noon for the Quad County area that spreads north- northeastward into the NV Basin and Range portions of the CWA going into the afternoon. Other areas not mentioned with those above in the region will see around a 15-25% chance for precipitation this afternoon as well. CAMs then have the precipitation coverage mostly in Pershing and Northern Washoe Counties by the time the evening hits with chances diminishing almost completely around midnight as showers exit to the north.

Chances that thunderstorms develop within these showers today look to be around 15-40% with the higher end chances in NE CA and the Sierra Front. While QPF values for today range between a trace to around 0.25 inches, some models are showing PWAT values up to around 0.8-1.0 inches in NE CA and W NV. If a storm develops, they are capable of producing bouts of heavy rainfall. Not anticipating major flooding concerns at this time with the quicker storm motion and how dry its been recently, but please be prepared for this. When looking at model convective parameters, storms could potentially be severe and contain both strong and erratic wind gusts up to around 60 mph and possibly hail up to 1 inch in size today. Increased outflow wind gusts may also cause blowing dust if they pass by desert sinks and playas in W NV this afternoon. There is an increased fire weather concern today due to these storms as well as the expected quick storm motion may allow for a mix of wet and dry thunderstorms today. Refer to the Fire Weather section and the current Red Flag Warning for more information on this. Please have a way to receive the latest weather information on this active weather day. It would also be a good idea to have an alternate plan ready especially if you plan to travel or be outdoors.

On Saturday, the trough begins its departure eastward leaving slight precipitation chances (15-20%) along the OR border in the afternoon. Behind Friday's showers and storms, temperatures become closer to mid-June normals on Saturday. Saturday's forecast highs for the NE CA and W NV valleys will be in the middle to upper 80s while the Sierra communities will be in the middle to upper 70s range. Forecast guidance then projects a ridge feature moving over the W CONUS on Sunday followed by high pressure building over the SW CONUS going into the middle of next week. This signals dry conditions for next week with temperatures warming again to where Moderate HeatRisk is seen within W NV beginning on Monday and localized Major HeatRisk in the NV Basin and Range by Tuesday. -078

AVIATION

The main concern today will come from the showers and thunderstorms expected in the region. NE CA and adjacent NV may see around a 15- 25% chance of isolated showers this morning. But by around 19/20Z, NE CA and the Sierra Front will have chances increase to around a 30- 80%. These chances then spread into the NV Basin and Range by the late afternoon. Sierra TAF sites look to see lesser chances (<25%), but may see vicinity storms this afternoon as well. Storms may contain increased gusty outflow winds up to 55 kts, brief periods of heavy rain and frequent lightning. Terrain obscuration, LLWS and turbulence may also be present near storm cores. Sub-VFR conditions are possible at most TAF sites should a storm develop or pass nearby. Outside of these potential storms, TAF sites expect to see west to northwest (south at KTVL) winds gusting up to around 20-25 kts (up to 30 kts at KMMH) during the afternoon and evening hours. While most precipitation chances end by 20/06Z, there may be some lingering showers going overnight going into Saturday along the OR border. HRICH/078

FIRE WEATHER

Critical fire weather concerns continue today with thunderstorm chances and coverage increasing across the region. Antecedent hot and dry conditions with poor overnight recoveries have helped in drying fuels further which also increases fire danger.

Storms will again move quickly today toward the north-northeast once developed, with a mix of wet and dry storm modes. This increases potential for dry lightning strikes outside of wet storm cores as well as dry storms that produce more lightning than moisture. Gusty, erratic outflows of 50-60 mph are possible, increasing the threat of rapid wind direction shifts. NE CA and portions of adjacent NV sees the thunderstorm potential begin in the morning before coverage spreads into W NV during the late morning/afternoon. Outside of storms, afternoon winds gusting up to around 25-35 mph are forecast within the region.

A Red Flag Warning is in effect today for W NV and portions of NE CA. See details in the Red Flag Warning product. HRICH/078

REV Watches/Warnings/Advisories

NV...Red Flag Warning from 8 AM this morning to 11 PM PDT this evening NVZ458.

Red Flag Warning from noon today to 9 PM PDT this evening NVZ420- 421.

Red Flag Warning from noon today to 11 PM PDT this evening NVZ423-429.

Heat Advisory until 5 AM PDT early this morning NVZ004.

CA...Red Flag Warning from 8 AM this morning to 11 PM PDT this evening CAZ270-278.