EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 152 AM EST SAT FEB 10 2018 VALID 12Z TUE FEB 13 2018 - 12Z SAT FEB 17 2018 ...WIDESPREAD PRECIPITATION EXPECTED IN THE SOUTHWEST NEXT WEEK... ...OVERVIEW... A CLOSED LOW WILL WOBBLE OFF THE COAST OF SOUTHERN CALIFORNIA NEXT WEEK BEFORE PUSHING INTO THE DESERT SOUTHWEST LATE IN THE WEEK BRINGING WIDESPREAD RAIN AND HIGH ELEVATION SNOW TO THE REGION. BROAD CYCLONIC FLOW OVER MOST OF THE REST OF THE LOWER 48 WILL BRING IN COLDER AIR TO MONTANA IN TO THE HIGH PLAINS WHILE MOST OF THE COUNTRY SEES ABOVE AVERAGE TEMPERATURES. ...GUIDANCE/UNCERTAINTY ASSESSMENT... LATEST GFS/ECMWF SOLUTIONS WERE IN GENERAL AGREEMENT WITH THEIR ENSEMBLE MEANS THROUGH THE PERIOD WITH THE OVERALL FLOW PATTERN. TIMING DIFFERENCES INCREASED BY LATER IN THE WEEK WITH THE WEAKENING UPPER LOW AND ALSO THE SOUTHWARD SURGE OF COOLER AIR FRI/SAT THROUGH THE PLAINS BUT A BLENDED SOLUTION SUFFICED GIVEN THE UPSTREAM DIFFERENCES OVER THE PACIFIC. ...WEATHER HIGHLIGHTS/THREATS... PRECIPITATION WILL EXPAND THROUGH SOUTHERN CALIFORNIA INTO ARIZONA AND EVENTUALLY NEW MEXICO AFTER THE UPPER LOW NUDGES EASTWARD MIDWEEK. SOUTHWESTERLY FLOW WILL HELP RAISE PW VALUES TO +2 TO +4 STANDARD DEVIATIONS WHICH SUGGESTS SOME LOCALLY HEAVY RAINFALL, DEPENDING ON OTHER FACTORS OF COURSE. TEMPERATURES WILL GENERALLY BE ABOVE AVERAGE OVERNIGHT BUT BELOW AVERAGE DURING THE DAY GIVEN CLOUD COVER AND PRECIPITATION. TO THE NORTH, GENERALLY BELOW AVERAGE TEMPERATURES ARE EXPECTED FROM MONTANA AND THE HIGH PLAINS INTO THE UPPER MIDWEST AS A COUPLE WEAKER SHORTWAVES GET SWEPT ALONG THE ZONAL TO WEST-SOUTHWEST UPPER-LEVEL FLOW FORECAST TO PERSIST OVER THE CENTRAL/EASTERN US. ABOVE AVERAGE TEMPERATURES ARE EXPECTED ACROSS MUCH OF THE EASTERN THIRD OF THE CONUS AS UPPER RIDGING MOVES INTO FLORIDA. 70S MAY REACH AS FAR NORTH AS CENTRAL VIRGINIA ON THURSDAY. COLD FRONT WILL KNOCK DOWN TEMPERATURES LATER IN THE WEEK, ESPECIALLY UP NORTH ALONG THE US/CANADIAN BORDER. FRACASSO