FXUS65 KREV 190857

AFDREV



Area Forecast Discussion

National Weather Service Reno NV

157 AM PDT Tue Aug 19 2025



.KEY MESSAGES...



* Warm and dry conditions are expected through Thursday. 



* A warming trend leads to hot temperatures by the second half of

  the week posing a risk for widespread heat impacts from Friday

  into Saturday.



* Monsoonal moisture also arrives for the second half of the week,

  bringing back showers and thunderstorms to the forecast through 

  the weekend.



&&



.DISCUSSION...



No significant changes are observed with the new forecast 

package. 



Current, satellite imagery shows clear skies and dry air already

in place in the region. This aligns with the initial state of the

model data this morning. Therefore, we are expecting an upper 

ridge to continue its retrograde trajectory into the Four Corners 

area and expanding into the Great Basin and the PacNW over the 

next several days. Temperatures will continue its warming trend 

as the high pressure settles in. Western NV valleys will rise to 

the upper 90s and near 100F, while Sierra valleys rise to the 

upper 80s and lower 90s by Friday. Friday is expected to be the 

hottest day of the week. These temperatures will be near-record 

highs for late August. Morning lows will also be of concern in 

Western NV as we don't cool of as much due to lingering clouds 

from daytime convection with lows in the mid 60s to lower 70s. If 

this trend continues, heat advisories will be very likely for 

Friday into Saturday morning.



The high pressure becomes more of a dirty ridge late this week 

and into the weekend. A plume of monsoonal moisture is advected to

the north under the ridge around Thursday and Friday. The 

earliest chances are for southern Mono and Mineral County by 

Thursday afternoon, but chances have dropped to less than 5%. By 

Friday, the storm track moves north and likely affecting areas 

from the Tahoe Basin, the Sierra Front and Churchill county with a

10-20%. The better and higher chances persist over Mono and 

Mineral counties. Saturday and Sunday have rain and storm chances

covering the whole area, but areas south of I-80 have the best 

chances for precipitation with at least 40-50% probability. North 

of I-80 the probability is 10-35%. Regardless, the main hazards 

with any storm this weekend will be periods of heavy rain, gusty 

winds, frequent lightning and small hail.



Next week, there is not a lot of change in terms of hazards as we

are expecting thunderstorms to remain in the forecast. However,

the upper ridge will be flattened by the approach of an upper

trough over the PacNW. This will help in the cool down we are

expecting to start late this weekend into early next week.



-HC



&&



.AVIATION...



VFR conditions continue through the 24 hour period. Main concern 

will be wind gusts of 15-25 kts between 20-03Z. Winds slowly subside

after sunset. Temperature rises the next few days bringing density

altitude concerns for western NV terminals.



-HC



&&



.FIRE WEATHER...



High pressure area over the region brings hot temperatures and dry

air. However, some gusty westerly winds (gusts to 25-30 mph 

possible at times) are expected today leading to elevated fire 

weather conditions mainly between 1 to 7 PM. The main areas of

concern will be the NV Basin and Range and extending south into

Mineral and Mono County. The overlap of dry air with min RH

generally below 15% and poor overnight recoveries will support the

elevated conditions. However, winds on Wednesday through Friday

appear to slow down with gusts below 20 mph.



Starting on Friday chances for showers and thunderstorms return to

the forecast. The main concern for fire interests is dry lightning

outside of rain cores, especially on Friday as a monsoonal

moisture plume is moving in from the south. For the restof the 

weekend, the influx of moisture should help decrease the risk of 

dry lightning, especially in areas south of US-50, where we are 

closer to the moisture source. The risk for dry lightning moves 

north through the weekend as the moisture continues to push in. 

Gusty outflow winds may initially fan new fires quickly. However,

the additional daytime moisture plus overnight recoveries 

improving to good or better over the weekend should help reduce 

the risk of fire conditions.



-HC



&&



.REV Watches/Warnings/Advisories...

NV...None.

CA...None.

&&



$$