Las Vegas, Nevada

• A few showers and thunderstorms remain possible through early this evening with localized heavy downpours, mainly across southern Nevada.
• Widespread wetting rain moves in late tonight and continues through Sunday afternoon. Locally heavy rainfall and a few instances of flash flooding will be possible.
• Conditions dry out on Monday as gusty north winds pick up across the region. Temperatures remain slightly below normal next week.

through next weekend.

Afternoon satellite imagery depicts a broad cloud shield extending northeastward off our approaching low pressure system off the Pacific Coast into the southern Great Basin. Meanwhile, to the south of this feature, filtered sunshine and modest clearing are allowing for some minor instability to develop across southern Nevada and northwest Arizona. With a little additional heating, surface based CAPE values are forecast to climb into the 250-500 j/kg range, will will be just enough to spark a few isolated showers and storms again this afternoon. Storms today are not expected to be as intense or widespread as observed Friday thanks to a sharp warming aloft and weaker wind shear, but the environment remains quite moist so brief but locally heavy downpours will remain possible.

By tonight, precipitation coverage will shift from predominantly convective to almost entirely stratiform as considerable subtropical moisture overspreads the region. This is in response to an impressive low pressure system off the SoCal coast that will move inland through Sunday. Todays forecast guidance appears to have converged on a common theme in terms of precipitation totals and coverage areas - with increased confidence in locally heavy rainfall totals exceeding 1 inch across Lincoln and northeastern Clark Counties. In fact, this mornings guidance suggests 24 hour precipitation totals in the Mesquite area may rival or exceed 24 hour totals rarely seen in a typical ten year interval. There is also concern that additional rainfall will cause additional flooding in the Colorado River Valley which is still recovering from pockets of locally heavy flooding on Friday. With these considerations in mind, went ahead and expanded the Flash Flood Watch further west. The flood watch remains in place for Northwest Arizona as well where confidence remains high that heavy rainfall will occur.

Closer to the Las Vegas Valley, some degree of rain shadowing remains expected which will work to limit the intensity of the rainfall. Nonetheless, still anticipate several periods of rain starting by late tonight and continuing into at least Sunday morning. Rainfall totals in general are expected to range in the 0.25-0.50 range, though there are hints the far southwest Vegas Valley may be a little lower due to the rainshadow effect. Periods of heavier rainfall are expected in the Spring Mountains, with rainfall totals exceeding 1 inch very likely. Snow levels will remain above 9000 feet through the event so we`re not anticipating any snow related impacts beyond accumulations at the top of Charleston Peak and higher reaches of Lee Canyon ski area. Points further west across Inyo county and western San Bernardino County can generally expect more showery conditions with generally light rainfall totals expected.

Conditions will tend to dry out from west to east Sunday afternoon, though pockets of embedded thunderstorms are expected

• especially across Northwest Arizona where flood risk will remain elevated. By Sunday night, drier conditions will overspread the region with northwesterly breezes filtering in behind the storm system.

The remainder of the week looks quiet through there may be some patchy morning fog in low lying and moist valleys which observed significant rainfall in the past week. Temperatures will hover a few degrees below normal.

For Harry Reid...For the 18Z Forecast Package...Sky conditions gradually deteriorate throughout the day as ceilings lower and precipitation chances increase. Isolated showers (and a 10% chance of thunder) are possible as early as mid-afternoon, but the more widespread precipitation arrives tonight. Latest guidance has a 50% chance of CIGs getting down to 2kft between 09z and 13z Sunday. Some visibility reductions due to rain are possible, but precipitation intensity should mostly be on the light side. Some improvement in sky conditions is anticipated Sunday afternoon, but timing and extent are still uncertain. South-southwest winds will be on the increase as this occurs.

For the rest of southern Nevada, northwest Arizona and southeast California...For the 18Z Forecast Package...Moisture and cloud cover continue to increase, with the best precipitation chances along and north of I-15 through the afternoon. This evening and overnight, rain chances spread to areas south and east. Precipitation intensity will largely be on the lighter side, but periods of increased rain rates and reduced visibility are possible. Expecting CIGs to drop down to 2-4kft across most of the area tonight and Sunday morning, resulting in MVFR conditions and significant terrain obscuration. Gusty south winds expected across our northwestern zones today, with lighter breezes elsewhere.

Spotters are encouraged to report any significant weather or impacts according to standard operating procedures.