000 FXUS65 KGGW 231625 AFDGGW AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 925 AM MST MON NOV 23 2009 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY... LATEST MOS IS SLIGHTLY COOLER FOR THIS AFTERNOON...OTHER THAN THAT CURRENT FORECAST IS IN GOOD SHAPE. PREVIOUS DISCUSSION... THE UPPER LOW WILL DROP INTO THE CENTRAL PLAINS TODAY WITH DRIER AIR ALOFT MOVING OVER THE FORECAST AREA AS UPPER RIDGING BUILDS IN FROM THE PACIFIC NORTHWEST. THE SKY SHOULD CLEAR FROM WEST TO EAST DURING THE AFTERNOON WITH A CLEAR SKY OVER THE ENTIRE AREA BY TONIGHT. AFTERNOON MAXIMUM TEMPERATURES WILL REMAIN ABOVE SEASONAL AVERAGES. WARM ADVECTION WILL COMMENCE MONDAY NIGHT CREATING RATHER LARGE MINIMUM TEMPERATURE DIFFERENCES BETWEEN THE HIGHER ELEVATIONS AND THE TYPICAL COLD AIR DRAINAGE LOCATIONS WHERE TEMPERATURES SHOULD BE CLOSE TO NORMAL. TUESDAY...A VIGOROUS SHORTWAVE TROUGH WILL DIG SOUTHEAST OVER THE CANADIAN PRAIRIES DRIVING A STRONG DRY COLD FRONT THROUGH NORTHEAST MONTANA. GUSTY NORTHWEST WIND WILL DEVELOP ALONG AND BEHIND THE COLD FRONT. 850MB WIND SPEEDS REACH UPWARDS OF 30-35KT AND COLD AIR ADVECTION AND A STRONG PRESSURE GRADIENT SHOULD KICK UP A RATHER BRISK SURFACE WIND. SUSTAINED WINDS COULD APPROACH AND REACH 15-20 MPH WITH GUSTS TO 40 MPH...SO A LWA MIGHT BE REQUIRED FOR FORT PECK LAKE. THE COLD BOUNDARY MOVES PAST THE CWA BORDERS BY SUNSET WHERE IT FINDS A BIT OF MOISTURE. ANY RESULTING SHOWERS SHOULD REMAIN BEYOND OUR BORDERS THROUGH TUESDAY NIGHT. WEDNESDAY...AN UPPER LEVEL RIDGE AMPLIFIES OVER WESTERN CONUS AS IT SLIDES EAST. THE COLD BOUNDARY RETREATS EAST THROUGH THE CWA BY LATE AFTERNOON. THE STRONG SURFACE HIGH AND APPROACHING UPPER RIDGE WILL BEGIN TO RAMP UP 1000MB-500MB THICKNESS HEIGHTS TO AS HIGH AS 550DM OVER THE SW CORNER TO INTRODUCE WAA FROM THE WEST. SCT .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... UPPER RIDGE WILL BRING A WARM AND DRY THANKSGIVING TO THE FORECAST AREA. THAT RIDGE WILL MOVE TO THE EAST ON FRIDAY WHILE THE WARM AND DRY WEATHER CONTINUES. WHILE 850 MB TEMPERATURES ARE FORECASTED TO BE +5 TO +8C BOTH DAYS...LIGHT WINDS AND LIMITED DAYLIGHT WILL LIMIT MIXING. ALSO...THE NIGHTTIME COLD AIR DRAINAGE BOTH WEDNESDAY NIGHT AND THURSDAY NIGHT WILL PROVIDE A SEASONABLY COLD START TO VALLEY LOCATIONS IN THE MORNING WHICH MAY LIMIT WARMING POTENTIAL EVEN FURTHER. COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY NIGHT FOLLOWED BY AN UPPER TROUGH ON SATURDAY. BOTH THE GFS AND ECMWF WANT TO SPLIT THE MOISTURE WITH THIS SYSTEM AROUND NORTHEAST MONTANA. WILL MAINTAIN A SLIGHT CHANCE OF RAIN AND SNOW AT THIS POINT AS MODELS HAVE BEEN CHANGING THE MOISTURE PLACEMENT FROM RUN TO RUN WITH THIS SYSTEM. GUSTY NORTHWEST WINDS AND COOLER TEMPERATURES ON SATURDAY APPEARS TO BE THE MAIN IMPACT AT THIS POINT. BEYOND SATURDAY...MODELS START TO DIFFER IN TIMING. IT LOOKS LIKE BOTH MODELS KEEP THE COLDER AIR OVER THE AREA ON SUNDAY ALTHOUGH ECMWF IS FASTER THAN THE GFS IN MOVING THE TROUGH TO THE EAST. LIKEWISE...THE ECMWF BRINGS THE NEXT UPPER RIDGE IN FASTER THAN THE GFS EARLY NEXT WEEK. EITHER WAY...A WARMING TREND FOR MONDAY LOOKS REASONABLE AT THIS TIME. FORRESTER && .AVIATION... VFR CONDITIONS WILL CONTINUE TODAY AND TONIGHT. MID LEVEL CLOUDS NEAR 10KFT AGL WILL CLEAR BY AFTERNOON. LIGHT AND VARIABLE WINDS WILL BECOME WEST TO NORTHWEST 10 TO 15 KNOTS BY LATE MORNING. THE WINDS WILL BECOME LIGHT AND VARIABLE AGAIN THIS EVENING. && .CLIMATE... THERE HAS BEEN NO PRECIPITATION AT THE GLASGOW AIRPORT SINCE A TRACE WAS RECEIVED ON OCTOBER 28TH. THAT IS A TOTAL OF 25 DAYS AS OF NOVEMBER 22ND. THAT TIES THE SECOND LONGEST NUMBER OF DAYS WITHOUT ANY PRECIPITATION AT THE GLASGOW AIRPORT. THE RECORD IS 28 DAYS FROM OCTOBER 20TH THROUGH NOVEMBER 16TH 1987. THERE IS CURRENTLY NO RAIN OR SNOW FORECAST UNTIL FRIDAY NIGHT. IF THIS HOLDS TRUE...THIS CURRENT DRY STREAK WILL BECOME THE LONGEST ON RECORD AT THE GLASGOW AIRPORT. THERE ARE LONGER DRY PERIODS PRIOR TO 1948 WHEN OBSERVATIONS WERE TAKEN DOWNTOWN IN GLASGOW. THE LONGEST SPAN NOT CORRUPTED BY MISSING DATA WAS A REMARKABLE 46 DAYS FROM SEPTEMBER 16TH TROUGH OCTOBER 31ST 1906. AJZ && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW