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Area Forecast Discussion (AFD)

Issued by Las Vegas, NV (VEF)

FXUS65 KVEF 211601 AAA

Area Forecast Discussion
National Weather Service Las Vegas NV
900 AM PDT Thu Jun 21 2018

.SYNOPSIS...Hot and dry conditions are expected through the next 
seven days with excessive heat expected today through Saturday. 
Slight cooling is likely Sunday before temperatures ramp back 
upwards next week. 

.UPDATE...Excessive Heat Warning goes into effect this morning as 
hot and dry conditions develop over the region. Calculations off the 
morning sounding show Las Vegas reaching 113 degrees today which is 
in line with current thinking. Still looking at some slight cooling 
over the next couple of days, but high heat impacts will still 
exist. No changes to the forecast. 

Previous Discussion
200 AM PDT Thu Jun 21 2018

.SHORT TERM...through Saturday night.

Strong 500mg ridge with 596dm heights centered over southern Arizona 
will be the catalyst for very hot temperatures the next few days. 
Today will likely be the hottest day as heights peak in the 592-594 
range and southwest breezes aid surface mixing. Heights drop ever so 
slightly on Friday in response to a shortwave traversing through the 
Great Basin and decrease a tad more on Saturday as stronger 
troughing digs into northern Utah.   The end result will the first 
true summer heat spell (right on time given the summer solstice 
arrives today at 3:07 am PDT), with highs across most of the Mojave 
Desert in the 105-115 degree range.  Lower elevations along the 
Colorado River will exceed 115 degrees while Death Valley soars into 
the 120s. 

The Excessive Heat Warning for most of the area, and Heat advisories 
for the upper elevations look good.  Be prepared for the hot 
conditions by staying hydrated and limiting time spent outdoors. 

.LONG TERM...Sunday through Thursday.

Not much change in the long term forecast. Still expecting a closed 
low to move into the central Rockies which will nudge the broad high 
pressure to our west. This will result in a slight drop in 
temperatures for Sunday and into early next week, but temperatures 
are still expected to be 5 to 10 degrees above seasonal normals 
through the work week. Models are in decent agreement on digging a 
Pacific NW trough into California and the Great Basin region during 
the Wednesday-Thursday time frame. Though, strength and location of 
this feature is not well resolved yet, some possible impacts look 
like gusty winds and a slight drop in temps by THU. Besides heat 
impacts, expect dry conditions with light to occasionally breezy 
afternoons under clear or mostly clear skies.


.AVIATION...For McCarran...Light and diurnal winds are expected 
through mid day Thursday with winds increasing out of the southwest 
in the afternoon with speeds around 10-15 kts and gusts over 20 
knots. Very hot temperatures are expected with highs around 110-112 
in Las Vegas. 

For the rest of southern Nevada, northwest Arizona and southeast 
California...Winds will be generally light through mid day Thursday 
then increasing out of the south around 10-20 kts most areas. Higher 
gusts likely in the western Mojave Desert.


.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating


LONG TERM...Kryston

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