653 
FXUS65 KTWC 101028
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
327 AM MST Wed Oct 10 2018

.SYNOPSIS...Dry with below average temperatures into Thursday. 
Increasing moisture from tropical system Sergio and a Pacific 
storm system will bring showers and thunderstorms to much of the 
region Thursday night into early next week.

&&

.DISCUSSION...A noteworthy change in the forecast was made on the 
morning package. The track of tropical system Sergio remained the 
same with the bulk of the moisture moving into northern Mexico and 
extreme southeast Arizona Thursday night and Friday. Remnants of 
Sergio will result in widespread moderate rainfall across the area 
with some locally heavy rainfall possible south and southeast of 
Tucson. The big change in the forecast deals with the low pressure 
system dropping south along the California coast behind remnants of 
Sergio. Latest models appeared to have a better handle on the 
evolution of this upper low as in tracks into southern California/ 
northern Baja by Sunday. This upper low will interact with the 
tropical moisture brought into the region with Sergio. Thus, it 
appears that rain chances will remain good over the weekend into 
early next week.  

&&

.AVIATION...Valid through 11/12Z.
Clear this morning, then mainly FEW-SCT clouds 4-8k ft AGL after 
10/19Z through the end of the forecast period. Surface wind variable 
in direction and mainly less than 12 kts. Aviation discussion not 
updated for TAF amendments.

&&

.FIRE WEATHER...Dry conditions are expected today with 
temperatures several degrees below normal. Increasing moisture 
associated with tropical system Sergio is expected to result in 
areas of showers and thunderstorms as early as Thursday afternoon 
and continuing through Friday night, with an emphasis on locations 
southeast of Tucson through Friday. A secondary weather system will 
keep unsettled weather continuing through the weekend and early next 
week with isolated to scattered showers and thunderstorms each day. 
20-foot winds will be terrain driven and generally less than 15 mph 
through the weekend.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

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