629 FXUS65 KTFX 261600 AFDTFX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1000 AM MDT FRI OCT 26 2012 .UPDATE...GOING FORECAST APPEARS TO BE IN GOOD SHAPE WITH THE EXPECTATIONS OF AN INCREASING CHANCE OF SHOWERS IN A MOIST NORTHWEST FLOW ALOFT. HAVE MADE VERY MINOR CHANGES TO WINDS FOR TODAY AS SOUTH TO SOUTHWEST WINDS ARE A BIT STRONGER THAN EXPECTED AT GREAT FALLS AND A FEW OTHER LOCATIONS OVER THE PLAINS. WILL BE KEEPING A CLOSE EYE ON WHETHER OR NOT THESE WINDS TRANSLATE INTO HIGHER THAN EXPECTED TEMPERATURES THIS AFTERNOON. AT THIS TIME IT APPEARS THAT LOW TO MID 30S STILL LOOKS GOOD FOR MOST LOCATIONS. MPJ && .AVIATION... UPDATED 1147Z. VFR CONDITION WILL PREVAIL FOR THE FIRST HALF OF THE TAF PERIOD AS AN UNSTABLE NORTHWESTERLY FLOW ALOFT CONTINUES TO MOVE ACROSS THE REGION. THERE IS A SLIGHT CHANCE OF PATCHY FOG THIS MORNING IN THE VALLEY LOCATIONS LIKE KHLN AND KBZN...HOWEVER HIGHER LEVEL CLOUDS MOVING ACROSS THE AREA SHOULD LIMIT FOG POTENTIAL. SCATTERED LIGHT SNOW SHOWERS WILL MOVE ACROSS THE ROCKY MOUNTAIN FRONT AND SOUTHWEST MONTANA GENERALLY AFTER 00Z. SUK && .PREV DISCUSSION... /ISSUED 547 AM MDT FRI OCT 26 2012/ TODAY THROUGH SUNDAY...MOIST AND UNSTABLE NORTHWEST FLOW ALOFT WILL CONTINUE OVER THE AREA TODAY AND WILL RESULT IN SCATTERED MOUNTAIN SNOW AND ISOLATED SNOW SHOWERS OVER THE PLAINS. SNOW ACCUMULATIONS OVER THE PLAINS WILL BE LIGHT. A RATHER VIGOROUS SHORT WAVE WILL BEGIN TO MOVE OVER THE AREA TONIGHT AND CONTINUE TO PUSH EASTWARD ON SATURDAY. PLENTY OF PACIFIC MOISTURE ASSOCIATED WITH THIS FEATURE SPELLS WIDESPREAD SNOW SHOWERS. ACCUMULATIONS DO NOT APPEAR SIGNIFICANT WITH ONE TO TWO INCHES POSSIBLE OVER THE PLAINS AND HIGHER AMOUNTS IN THE MOUNTAINS. SNOW SHOWERS WILL GRADUALLY TAPER OFF SATURDAY AFTERNOON AS THE SHORT WAVE PUSHES FURTHER EAST. WEAK UPPER RIDGING DEVELOPS OVER THE AREA SUNDAY. PACIFIC MOISTURE WILL CONTINUE TO MOVE THROUGH THE RIDGE POSITION AND...ALONG WITH TRANSIENT SHORT WAVE ENERGY AND WARMING TEMPERATURES DUE TO SUBSIDENCE...WILL AID IN THE CONTINUED DEVELOPMENT OF SCATTERED RAIN OR RAIN AND SNOW SHOWERS. TEMPERATURES WILL RISE INTO THE 30S TODAY AND SATURDAY BUT WILL REMAIN SOME 20 DEGREES BELOW SEASONAL AVERAGES. THE AUTUMN COLD OF RECENT DAYS WILL SLOWLY ERODE ON SUNDAY AS AFTERNOON READINGS WILL REACH THE LOWER 50S SOME AREAS. EMANUEL SUNDAY NIGHT THROUGH FRIDAY...A WEAK UPPER LEVEL RIDGE WILL DOMINATE THE WEATHER PATTERN FOR MUCH OF THE LONG TERM PERIOD. IT SHOULD BE NOTED THAT ALTHOUGH THE RIDGE IS THE LARGE SCALE SYNOPTIC FEATURE MULTIPLE SHORTWAVE TROUGHS WILL MOVE THROUGH DURING THE TIME PERIOD AND WILL BRING SOME MOISTURE AND INSTABILITY TO THE REGION. THE FIRST EXAMPLE OF THESE SHORTWAVES OCCURS SUNDAY NIGHT AND MONDAY MORNING. THESE MOIST CONDITIONS WILL ALLOW FOR MOSTLY MOUNTAIN BASED PRECIPITATION BUT HAVE INCREASED CHANCES OVER THE LOWER ELEVATIONS AS WELL DUE TO DECENT MOISTURE AND INSTABILITY BY MONDAY MORNING. TEMPERATURES WILL BEGIN TO WARM BACK TO SEASONAL AVERAGES BY MONDAY AFTERNOON AND SOME LOCATIONS COULD SEE NEARLY 10 DEGREES ABOVE SEASONAL NORMALS TUESDAY WEDNESDAY AND THURSDAY. THERE IS SOME LATE FORECAST PERIOD MODEL DISAGREEMENT ON HOW AND WHEN THE UPPER LEVEL RIDGE BREAKS DOWN. BOTH MAJOR MODELS HAVE A WEAK LOW PRESSURE SYSTEM MOVE THROUGH BY FRIDAY AND DROPPING THE TEMPERATURES DOWN TOWARD SEASONAL VALUES WITH SOME ADDITIONAL PRECIPITATION. EVENTUALLY A LARGE SCALE LOW PRESSURE SYSTEM DOES MOVE OVER THE PACIFIC NORTHWEST...AND CHANGE THE WEATHER PATTERN TOWARDS COLDER AND WETTER CONDITIONS. HOWEVER THIS IS BEYOND THE FORECAST PERIOD AND CONFIDENCE OVER TIMING AND STRENGTH OF THIS PATTERN CHANGING SYSTEM IS VERY LOW. SUK && .PRELIMINARY POINT TEMPS/POPS... GTF 36 22 38 29 / 20 60 50 30 CTB 33 15 31 22 / 20 60 40 30 HLN 38 24 40 29 / 20 60 40 30 BZN 38 24 40 28 / 20 60 40 30 WEY 31 14 36 19 / 30 60 50 50 DLN 36 22 43 28 / 20 60 30 20 HVR 31 15 33 21 / 20 30 30 20 LWT 33 20 34 25 / 30 50 50 20 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ WEATHER.GOV/GREATFALLS