000 FXUS65 KTFX 012349 AAA AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 450 PM MST SUN FEB 1 2009 UPDATE AVIATION SECTION... .DISCUSSION... TONIGHT THROUGH TUESDAY...EXPECT NORTHWEST FLOW ALOFT OVER THE FORECAST AREA THROUGH TUESDAY. MODELS ARE ON THE SAME PAGE IN SPREADING INCREASING MOISTURE OVER THE FORECAST AREA TONIGHT INTO EARLY MONDAY. OROGRAPHIC EFFECTS WILL LEAD TO SNOW OVER THE MOUNTAINS. A LITTLE MORE TRICKY AS TO WHETHER THERE WILL BE PRECIPITATION FOR THE PLAINS AND VALLEYS. DO SEE AT LEAST SOME WEAK LIFT FOR THE LOWER ELEVATIONS SO WILL GO WITH SLIGHT CHANCE TO CHANCE POPS THERE. MODELS ARE ALSO ON THE SAME PAGE IN DECREASING MOISTURE MONDAY NIGHT SO WILL CONTINUE THE IDEA OF A DECREASING TREND WITH THE CHANCES OF PRECIPITATION. TUESDAY A STRONG UPPER RIDGE WILL BE APPROACHING THE FORECAST AREA FROM THE WEST AND WILL CONTINUE WITH THE DRY FORECAST. AS FOR THE HIGH WIND WATCH HAVE DECIDED TO CONTINUE IT. THERE ARE SOME INDICATIONS THAT THE FLOW ALOFT WILL BE WEAKER THAN ORIGINALLY EXPECTED. HOWEVER THE FLOW ALOFT IS STILL STRONG ENOUGH THAT WINDS WOULD NOT HAVE TO INCREASE MUCH FOR A HIGH WIND EVENT TO OCCUR. WILL LET EVENING SHIFT LOOK AT LATER MODEL DATA AND OBSERVATIONS AND MAKE A FINAL DECISION ON WHETHER TO UPGRADE THE WATCH TO A WARNING OR TO DROP THE WATCH. BLANK TUESDAY NIGHT THROUGH FRIDAY NIGHT...A LARGE UPPER LEVEL HIGH PRESSURE RIDGE SITS OVER THE ROCKIES AND THE AIRMASS WILL BE WARM AND DRY. AN UPPER LEVEL SHORTWAVE WILL BE MOVING THROUGH THE RIDGE IN ALBERTA AND THIS WILL DEVELOP A SURFACE TROF ALONG THE LEE OF THE ROCKIES IN ALBERTA. THIS LEE TROF WILL DEVELOP SOUTHWARD AND KEEP BREEZY CONDITIONS THROUGH WEDNESDAY ALONG THE ROCKIES AND ADJACENT PLAINS. ANOTHER SHORTWAVE WILL FLATTEN THE RIDGE ON WEDNESDAY. MOISTURE WILL MOVE OVER THE NORTHERN ROCKIES AND A CHANCE OF PRECIP WILL RESULT. ELSEWHERE CONDITIONS WILL REMAIN TOO DRY FOR PRECIP. BY LATE WEDNESDAY...A SPLIT UPPER LEVEL LOW PRESSURE TROF OVER THE EASTERN PACIFIC WILL APPROACH THE WEST COAST. THE SOUTHERN PORTION WILL MOVE OVER THE COAST OF NORTHERN CALIFORNIA ON THURSDAY. UPPER LEVEL FLOW OVER THE ZONES WILL SWITCH TO THE SOUTHWEST DURING THE DAY AND MOISTURE AHEAD OF THE LOW PRESSURE CENTER WILL BEGIN TO MOVE INTO SOUTHWEST MONTANA AND WORK ITS WAY NORTH. FALLING HEIGHTS WILL BEGINS TO LOWER MAX TEMPS. POPS WILL BE INCREASED THURSDAY NIGHT OVER SOUTHWEST MONTANA...AND HIGHER POPS WILL BE REQUIRED ACROSS THE CENTRAL CWA AND PERHAPS EVEN INTO THE NORTHEAST ZONES. THIS SYSTEM WILL REMAIN QUITE WEAK AND SIGNIFICANT PRECIPITATION AMOUNTS ARE NOT EXPECTED. TEMPS WILL CONTINUE TO TREND DOWNWARDS AS A COLD FRONT PASSAGE ASSOCIATED WITH THE NORTHERN PORTION OF THE LOW PRESSURE TROF MOVES ACROSS THE NORTHERN ROCKIES EARLY FRIDAY. THIS WILL ALSO INCREASE THE CHANCE OF PRECIP OVER THE NORTHERN ZONES HOWEVER TEMPS WILL REMAIN ABOVE NORMALS THROUGH FRIDAY NIGHT. ZELZER SATURDAY AND SUNDAY...MODELS CONTINUE TO BRING A BROAD PACIFIC LOW PRESSURE TROUGH INTO MONTANA OVER THE WEEKEND. MAINTAINED CLIMATOLOGY FOR PRECIPITATION CHANCES. A TIGHT PRESSURE GRADIENT WILL WILL CREATE GUSTY WINDS ALONG THE FRONT RANGE AND THE NORTH CENTRAL PLAINS THROUGH THE PERIOD. TEMPERATURES ARE EXPECTED TO BE SLIGHTLY ABOVE SEASONAL AVERAGES. SAUCIER && .AVIATION... MODERATE TO STRONG NW FLOW ALOFT WILL CONTINUE THROUGH THE NEXT 24HRS AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST. INCREASING MOISTURE IN THE FLOW WILL BRING INCREASING CLOUDS WITH BASES LOWERING TO 6000-12000 FT AGL BY LATE TONIGHT...AND EVEN TO MVFR LEVELS DURING THE DAY ON MONDAY. COULD SEE SOME LIGHT PRECIPITATION AFTER 10Z TONIGHT AS A WEAK DISTURBANCE MOVES THROUGH THE FLOW. PRECIP WILL INITIALLY BE CONFINED TO THE HIGHER TERRAIN...THEN SPREAD EAST AFTER 15Z. VFR CONDITIONS WILL PREVAIL...WITH LOCAL MVFR CONDITIONS IN AREAS OF PRECIPITATION ON MONDAY. SURFACE WINDS WILL INCREASE LATE TONIGHT THROUGH MONDAY MORNING OVER WESTERN PORTIONS OF NORTH CENTRAL MT AS THE DISTURBANCE APPROACHES WITH GUSTS IN EXCESS OF 50KTS POSSIBLE ALONG THE IMMEDIATE EAST SLOPES OF THE ROCKIES. DB && .PRELIMINARY POINT TEMPS/POPS... GTF 27 47 33 54 / 20 20 10 0 CTB 23 42 31 51 / 20 20 10 0 HLN 24 46 31 48 / 10 20 10 0 BZN 18 43 23 47 / 10 30 10 0 WEY 7 29 8 32 / 20 50 20 0 DLN 20 40 23 45 / 10 20 10 0 HVR 14 37 16 39 / 10 20 10 0 LWT 18 41 27 49 / 10 20 10 0 && .TFX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH FROM MIDNIGHT MST TONIGHT THROUGH MONDAY AFTERNOON FOR MTZ009-048. && $$ SHORT TERM...BLANK LONG TERM...HOENISCH AVIATION...DB WEATHER.GOV/GREATFALLS