Area Forecast Discussion

KEY MESSAGES

* Hotter than normal temperatures will continue through the forecast period.

* Moisture will increase this weekend leading to a slight chance of showers and thunderstorms over portions of eastern Nevada and western Arizona.

DISCUSSION

Today through Wednesday.

Hotter than normal temperatures will continue through the forecast period. Temperatures this afternoon will top out around 4 to 8 degrees above normal, and will warm a degree or two on top of that from today to tomorrow. This will result in widespread Moderate HeatRisk (Level 2 of 4) on Friday, with pockets of Major HeatRisk (Level 3 of 4) for portions of the Colorado River Valley, Las Vegas Valley, Amargosa Valley, and Death Valley National Park. Temperatures will hold steady over the weekend, fluctuating a degree or two from day to day before taking off early next week. This will allow for widespread Moderate HeatRisk to persist across the region through the weekend with pockets of Major HeatRisk persisting in the previously mentioned areas. As temperatures take off next week, HeatRisk will also increase with Major HeatRisk becoming more widespread and the potential for Extreme HeatRisk (Level 4 of 4) to begin popping up in some areas.

Current water vapor satellite imagery shows the MCV mentioned in the previous discussion continuing to push north along the Gulf of California/Baja Peninsula. This moisture will begin to creep up the Colorado River Valley late tomorrow, spilling over into neighboring counties over the weekend. Precipitable water values will be around 0.75 to 1.0 inches in Mohave, Clark, southeastern San Bernardino, and eastern Lincoln counties, with locally higher PWs in the Colorado River Valley. However, the presence of anomalous moisture alone is not enough for convection to develop. We will be dependent on daytime heating as our main source of lift for the development of showers and thunderstorms, meaning areas of higher terrain will be favored for the development of isolated convection over the weekend pending any decaying MCVs drifting into our forecast area. In addition to the lack of forcing, the lower levels of the atmosphere will remain relatively dry through the weekend as this moisture will predominantly be limited to the mid- levels of the atmosphere. This means that virga showers capable of resulting in strong gusty winds and dry lightning will be possible with convection that does not end up producing moderate- to- heavy rain. Chances for precipitation will decrease as we head into next week and moisture begins to move out of the area.

AVIATION...For Harry Reid...For the 00Z Forecast Package

Winds are expected to remain less than 8 knots into this evening with winds varying from northeast to southeast, before settling to the southwest after sunset. We will continue to see hazy conditions through sunset with visibility generally remaining above 6SM. Improvement is expected overnight. Temperatures will remain 100 deg or above through 03-04Z before dropping. No operationally significant cloud cover, although we will start to see some increasing high clouds from the south late this evening. High temperature Friday is 108F, with best chances of 100F or greater between 19Z and 04Z.

For the rest of southern Nevada, northwest Arizona and southeast California...For the 00Z Forecast Package...Winds will generally fall below 10 knots over most areas after sunset with typical diurnal directions. Winds at KDAG will remain gusty out of the west through much of the overnight period with speeds between 10-20 knots with occasional gusts to 25 knots. Will need to watch for the potential of gusty outflow winds at KBIH Friday afternoon. Thunderstorms are not expected at the terminal, but some wind impacts are possible. Cloud or weather impacts are not expected over the remaining TAF sites.

SPOTTER INFORMATION STATEMENT

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