http://www.wrh.noaa.gov/fgz
THURSDAY THROUGH SATURDAY...AN UPPER LEVEL CLOSED LOW WILL DEVELOP OFF THE CALIFORNIA COAST AND LATEST FORECAST MODEL GUIDANCE ATTEMPTS TO MOVE IT OUT MORE RAPIDLY THAN PREVIOUS FORECAST MODEL RUNS. THIS WILL BE PROBLEMATIC FOR TIMING AND DURATION FOR THE EXTENDED FORECAST. HENCE OUR EXTENDED FORECAST GRIDS WILL SPREAD CHANCES FOR PRECIPITATION BROADLY OVER THIS TIME PERIOD UNTIL THE SOLUTION WITH THIS LOW BECOMES MORE CERTAIN. THIS SYSTEM HAS THE POTENTIAL TO PULSE DISTURBANCES OVER ARIZONA THROUGH NEXT WEEKEND WITH PERIODS OF DRY THEN SHOWERY WEATHER CONDITIONS. HOWEVER WITH CHANGING FORECAST GUIDANCE THIS FAR OUT IN THE FORECAST PERIOD CONFIDENCE IS EXTREMELY LOW ON THE EXACT TIMING OF THESE PULSES AND WHERE THIS CLOSED LOW WILL POSITION ITSELF. THERE IS ANOTHER POSSIBILITY THAT TOO MUCH DRY AIR MAY WRAP AROUND THIS SYSTEM CAUSING ONLY LIGHT PRECIP AMOUNTS. THERE IS ALSO EQUAL CHANCES AT THIS POINT THAT SOME AREAS OF NORTHERN ARIZONA MAY RECEIVE SIGNIFICANT AMOUNTS OF RAIN. THE AREA EAST OF A LINE FROM PAGE TO PHOENIX IS MOST FAVORABLE TO RECEIVE WIDESPREAD PRECIPITATION.
