

http://www.wrh.noaa.gov/fgz
AREA FORECAST DISCUSSION
FXUS65 KFGZ 132200 AFDFGZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 245 PM MST WED DEC 13 2006 .SYNOPSIS...A HIGH PRESSURE RIDGE ALOFT WILL BRING ABOVE NORMAL AFTERNOON TEMPERATURES AND DRY CONDITIONS FOR THE REST OF THE WEEK. A STRONG PACIFIC STORM WILL MOVE INTO THE NORTHLAND OVER THE WEEKEND. EXPECT INCREASING SOUTHWEST WINDS AND CLOUDINESS...WITH A CHANCE FOR RAIN AND SNOW BEGINNING SATURDAY NIGHT AND LASTING INTO EARLY NEXT WEEK. && .DISCUSSION...A FLAT RIDGE WILL BE OVER THE FORECAST AREA THROUGH THURSDAY WITH ABOVE NORMAL DAYTIME TEMPERATURES AND LIGHT WINDS. EXPECT SOME HIGH CLOUDS AT TIMES FROM SYSTEMS PASSING BY TO OUR NORTH. BY FRIDAY...A DEVELOPING LONGWAVE TROUGH OVER THE WESTERN U.S. WILL PUSH A COLD FRONT INTO SOUTHERN UTAH. IT WILL REMAIN DRY AND WARMER THAN NORMAL OVER ARIZONA FRIDAY...BUT PRESSURE GRADIENTS WILL STRENGTHEN AHEAD OF THE FRONT...AND BREEZY SOUTHWEST WINDS WILL DEVELOP. FOR SATURDAY...MODELS ARE IN GOOD AGREEMENT THAT SHORTWAVE ENERGY WILL DIVE THROUGH THE SOUTHERN END OF THE WESTERN U.S. TROUGH...APPROACHING SOUTHERN CALIFORNIA BY AFTN/EVENING. THIS TROUGH IS EXPECTED TO CONTINUE TO APPROACH THE STATE SUNDAY...THEN CUT OFF OVER SRN CALIFORNIA OR ARIZONA BY EARLY NEXT WEEK. THE DETAILS OF THE STORMS TRACK WILL DETERMINE WHERE THE HEAVIEST PRECIPITATION FALLS...AND THESE DETAILS ARE STILL UNCERTAIN...BUT SOME LOCATIONS COULD SEE SIGNIFICANT SNOWFALL WITH SNOW LEVELS POSSIBLY FALLING AS LOW AS 3500 FEET. THE LATEST GFS MODEL TARGETS SUNDAY NIGHT THROUGH MONDAY NIGHT AS THE MOST LIKELY TIME PERIOD FOR SIGNIFICANT PRECIPITATION WITH DEEP SATURATION...AND OUR POP GRIDS REFLECT THIS. THERE WILL LIKELY BE SOME ADJUSTMENTS MADE TO THIS FORECAST AS THE EVENT DRAWS CLOSER...SO STAY TUNED.