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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 93 °
• Low: 63 °
• Clear

• Thursday
• 
• High: 93 °
• Low: 64 °
• Clear

• Friday
• 
• High: 90 °
• Low: 59 °
• Clear

• Saturday
• 
• High: 86 °
• Low: 57 °
• Clear

• Sunday
• 
• High: 91 °
• Low: 61 °
• Clear

Area forecast discussion 
National Weather Service Las Vegas Nevada 
254 am PDT Wednesday may 16 2012 


Synopsis...a weak ridge of high pressure will be over the area 
today...ahead of a low pressure system moving into the area late 
Thursday which then shifts east on Friday. This will result 
in breezy to windy conditions over much of the region Thursday and 
Friday. However dry conditions are looked for along with well above 
normal temperatures through Thursday. 
&& 


Short term...today through Friday night...the upper low which is 
currently centered over central Nevada early this morning will 
continue to shift east out of the district today as a weak short 
wave ridge builds across the region. However another low pressure 
system will begin to move into the southern Great Basin late 
Thursday and cross over the County Warning Area on Friday. Once again this system is 
expected to bring very limited moisture to the forecast area with 
only a slight chance of thunderstorms over northern mountains on 
Friday. 


The main impact will once again be winds during the short term. 
Under the short wave ridge today...winds should generally be at most 
breezy this afternoon...however winds are expected to increase on 
Thursday as the next system begins to move over the area. Wind 
advisories may need to be issued in later packages. However there is 
the potential for strong downslope winds to form on the east side of 
the area mountains with the main concern at this time being the 
southern Sierra/Owens Valley and a high wind watch will be issued 
with this morning package. 


Above normal temperatures are expected to continue today and 
Thursday with the first 100 degree reading of the year possible at 
Las Vegas McCarran International Airport. Cooling will be seen on 
Friday as the trough crosses the area with temperatures dropping 
5-10 degrees for Friday afternoon...which will place temperatures 
near normal for the first time in almost a week. 


Long term...after a Little Break from the well above normal 
temperatures on Friday...readings will rise on Saturday as the middle 
and upper level flow flattens out. Temperatures should rise back to around 
4 degrees above normal for highs on Saturday. Further warming should 
take place on Sunday as ridging aloft becomes centered over the 
west. By Monday a middle/upper level trough is forecast to approach the 
coast of British Columbia which will increase southwest flow across 
our area as we move on the back side of the ridge. This would push 
temperatures up even further...with highs a good 8 to 10 degrees above 
normal unless a substantial amount of high level cloud cover moves 
on in ahead of the trough. From Saturday through Monday I generally 
weighted the forecast towards the warmer GFS bias corrected and 
European model (ecmwf) MOS numbers which look more in-line with forecast soundings 
and prognosticated 700 mb temperatures. Models are all over the place with the 
passage of the trough axis both in timing and depth. The GFS is 
shallower and slower while the European model (ecmwf) and Gem are deeper. For now I 
generally blended the models and bumped up winds from the southwest 
on Tuesday and also showed a drop in temperatures with highs only 5-7 
degrees above normal. The trough per the European model (ecmwf) moves through on 
Tuesday...while the Gem moves it through then before dropping in a 
big closed upper low for Wednesday. Depending on how quick the 
trough moves in and how deep it turns out...some adjusting may need 
to be done with forecasted temperatures but for now the overall forecast is 
a middle of the Road blend. 
&& 


Aviation...for McCarran...mainly east-southeast to southeast winds 
at 5-10 kts are expected late this morning into early this afternoon 
with winds transitioning more to the south between 23z today and 
03z Thursday. As winds transition more to the south gusts as high as 
20 kts may occur. Stronger southwest winds possibly gusting over 25 
kts may occur on Thursday. 


For the rest of southern Nevada...northwest Arizona...and southeast 
California...winds will mainly follow diurnal trends across the area 
through tonight with the highest gusts being 15-20 kts under a clear 
sky. Stronger southwest to west winds are expected on Thursday 
especially in the afternoon and evening. Many areas could see gusts 
of 25-35 kts...with the strongest gusts - potentially over 50 kts - 
in the eastern slopes of the southern Sierra Nevada and Owens 
Valley. Mechanical turbulence aloft will be possible in this area. 
&& 


Fire weather...low pressure will shift east of the area today and 
although winds will be less...continued very dry conditions will 
prevail over the area. Another low pressure system will begin to 
move into the region on Thursday and cross over the area on Friday. 
This will result in another round of gusty winds. Limited moisture 
associated with this second system...thus continued dry. The 
combination of winds/dry airmass/dry fuels may create the potential 
for erratic fire behavior. For now will issue a Fire Weather Watch 
for the most likely areas...which are Arizona zone 102 and Nevada zone 461 
for Thursday afternoon and evening. However additional products may 
be need in later packages. 
&& 


Vef watches/warnings/advisories... 
Nevada...Fire Weather Watch from Thursday afternoon through Thursday 
evening for nvz461. 
Arizona...Fire Weather Watch from Thursday afternoon through Thursday 
evening for azz102. 
California...high wind watch from Thursday afternoon through Thursday 
evening for caz519-520. 
&& 


$$ 


Jensen/stachelski 


Http://weather.Gov/lasvegas