876 
fxus65 kpsr 200224 
afdpsr 


Area forecast discussion...correction for time stamp 
National Weather Service Phoenix Arizona 
725 PM MST Tuesday Aug 19 2008 


South-central and southwest Arizona...and southeast California 
forecast discussion 


Synopsis... 
drier air is expected across the area this week as high pressure 
builds over Southern California and south-central Arizona. The only 
threat for afternoon thunderstorms will be over the higher terrain 
of south-central Arizona...well east of Phoenix. Daytime 
temperatures will warm slightly and stay above normal the remainder 
of the week. 


&& 


Discussion... 
skies were clear across the forecast area (southeast California to south 
central az) at 02z...a reflection of a more drier and stable airmass. 


A series of weak Pacific troughs are forecast to move into the western 
states north of Arizona this week. This will veer winds aloft to a more 
westerly direction...importing drier air and warmer stabilizing 
temperatures aloft. Current dry forecasts through the remainder of 
the week look OK. No updates planned. 


Thursday/Friday...conditioned dry conditions with slightly above 
average temperatures for this time of year. 


Previous discussion... 
the upcoming weekend through the first part of next week...the ridge 
shifts with the 500-400mb high centering somewhere over the 
Arizona-New Mexico border. The GFS and European model (ecmwf) suggest that the flow 
becomes more southeasterly and favorable for increasing surface dew 
points and boundary layer moisture over portions of our County Warning Area. The 
moisture could lead to the return of showers and thunderstorms 
across portions of eastern Arizona...so maintaining a low grade 
monsoon forecast or slight chance probability of precipitation over our eastern zones 
Saturday...spreading the slight chances westward into the lower 
deserts by early next week. 


&& 


Aviation... 
southeast California to south central Arizona...including kphx...kiwa...knyl... 
kblh...and kipl airfields. Clear skies and light winds under 10 
knots are forecast through at least 04z Thursday. 


Aviation discussion not updated for amended tafs. 


&& 


Fire weather... 
Thursday through Monday... 
dry air has spread over most of our forecast area. Just a slight 
chance /less than 20 percent/ of precipitation can be expected over 
the mountainous areas of southern Gila County the next few days. 
Temperatures and relative humidity values will show little fluctuation day-to-day. 
Winds will feature typical diurnal patterns though a bit more of a 
westerly component. Moisture levels may begin to slightly increase 
early next week. 


&& 


Psr watches/warnings/advisories... 


Arizona...none. 


California...none. 


&& 


$$ 


National Weather Service Phoenix is on the internet at 


Weather.Gov/Phoenix 


Discussion...vasquez/wanek/Meyers 
aviation...iniguez 
fire weather...iniguez