000 FXUS65 KTFX 121124 AAA AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 507 AM MDT SUN JUN 12 2005 .DISCUSSION... TODAY THROUGH TUESDAY...A NEGATIVELY TILTED LOW PRESSURE TROF LIES WEST OF THE ROCKIES AND IS SLOWLY MOVING EAST. AT THE SURFACE...LOW PRESSURE REMAINS OVER SOUTHERN ALBERTA AND SASKATCHEWAN WITH HIGH PRESSURE WEST OF THE DIVIDE AND IS MAINTAINING LIGHT SOUTHWEST FLOW AT THE SURFACE. PRECIPITATION WILL DEVELOP ACROSS THE ZONES BUT AT THE MOMENT SEEMS TO BE LAGGING WEST OF THE LATEST PROGS. DURING THE MORNING THE UPPER LEVEL TROF MOVES OVER THE WESTERN MOUNTAINS AND GOOD MOISTURE CONVERGENCE DEVELOPS...AND MOVES OVER THE EASTERN ZONES BY AFTERNOON. THE AIRMASS SHOULD BECOME SATURATED THROUGH ALL LEVELS BY MID-DAY. THE AIRMASS IS SLIGHTLY UNSTABLE AND MOST INSTABILITY WILL BE OVER EASTERN MONTANA...AND GOOD HELICITY DEVELOPS OVER THE NORTHEAST ZONES BY AFTERNOON AS WELL. TEMPS TAKE A BIG DROP TODAY AS THE FRONT COMES THRU BUT WILL BEGIN TO RECOVER QUICKLY ON MONDAY. WEAK RIDGING BEHIND THE LOW PRESSURE SYSTEM WILL ALLOW THE AIRMASS TO DRY...AND WITH AFTERNOON HEATING...THE NORTHEAST ZONES SHOULD BECOME UNSTABLE DURING THE AFTERNOON. THE AIRMASS CONTINUES TO WARM AND STAY DRY THROUGH TUESDAY. ZELZER TUESDAY NIGHT THROUGH SUNDAY...A BROAD UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST AND AN UPPER LEVEL RIDGE OVER THE CENTRAL U.S. WILL RESULT IN SOUTHWEST FLOW ALOFT THROUGH THE EXTENDED PERIOD. THE UPPER LEVEL LOW WILL SLOWLY MOVE EAST LATE IN THE WEEK AND INTO THE WEEKEND. WEAK WAVES WILL ROTATE AROUND THE LOW AND MOVE OVER THE REGION BRINGING PERIODS OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. TEMPERATURES WILL FINALLY WARM TO AROUND NORMAL ALONG THE DIVIDE AND CLIMB ABOVE NORMAL OVER CENTRAL MONTANA. MEIER && .AVIATION... UPDATED AT 1107Z... UPPER LOW OVER THE PACIFIC NORTHWEST WILL BRING NUMEROUS SHOWERS WITH AFTERNOON AND EVENING THUNDERSTORMS EAST OF THE KBZN AND KGTF LINE. WEAK SURFACE PRESSURE GRADIENTS FOR LIGHT WINDS. THERE WILL BE WIDESPREAD MVFR WITH SOME IFR AFT 17Z...ESPECIALLY ACROSS NORTH CENTRAL MONTANA. WILLIAMSON DC && .PRELIMINARY POINT TEMPS/POPS... GTF 58 45 68 45 / 100 90 30 10 CTB 58 45 66 43 / 100 80 30 10 HLN 56 46 71 46 / 100 80 30 10 BZN 54 40 65 40 / 100 80 30 10 WEY 53 32 60 30 / 90 70 20 0 DLN 56 36 67 40 / 80 50 10 10 HVR 68 50 72 48 / 80 100 50 20 LWT 55 43 64 44 / 100 90 60 20 && .TFX WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH UNTIL 6 PM MONDAY FOR MTZ009-MTZ011-MTZ012-MTZ013- MTZ014-MTZ047-MTZ048-MTZ050-MTZ051-MTZ054. && $$ WEATHER.GOV/GREATFALLS